title: Quadratic Basis Pursuit

abstract:
  In many compressive sensing problems today, the relationship between the
measurements and the unknowns could be nonlinear. Traditional treatment of such
nonlinear relationships have been to approximate the nonlinearity via a linear
model and the subsequent un-modeled dynamics as noise. The ability to more
accurately characterize nonlinear models has the potential to improve the
results in both existing compressive sensing applications and those where a
linear approximation does not suffice, e.g., phase retrieval. In this paper, we
extend the classical compressive sensing framework to a second-order Taylor
expansion of the nonlinearity. Using a lifting technique and a method we call
quadratic basis pursuit, we show that the sparse signal can be recovered
exactly when the sampling rate is sufficiently high. We further present
efficient numerical algorithms to recover sparse signals in second-order
nonlinear systems, which are considerably more difficult to solve than their
linear counterparts in sparse optimization.


title: Helicity separation in Heavy-Ion Collisions

abstract:
  We study the P-odd effects related to the vorticity of the medium formed in
noncentral heavy ion collisions. Using the kinetic Quark-Gluon Strings Model we
perform the numerical simulations of the vorticity and hydrodynamical helicity
for the various atomic numbers, energies and centralities. We observed the
vortical structures typically occupying the relatively small fraction of the
fireball volume. In the course of numerical simulations the noticeable
hydrodanamical helicity was observed manifesting the specific mirror behaviour
with respect to the reaction plane. The effect is maximal at the NICA and FAIR
energy range.


title:
The VLA 1.4GHz Survey of the Extended Chandra Deep Field South: Second
  Data Release

abstract:
  Deep radio observations at 1.4GHz for the Extended Chandra Deep Field South
were performed in June through September of 2007 and presented in a first data
release (Miller et al. 2008). The survey was made using six separate pointings
of the Very Large Array (VLA) with over 40 hours of observation per pointing.
In the current paper, we improve on the data reduction to produce a second data
release (DR2) mosaic image. This DR2 image covers an area of about a third of a
square degree and reaches a best rms sensitivity of 6 uJy and has a typical
sensitivity of 7.4 uJy per 2.8" by 1.6" beam. We also present a more
comprehensive catalog, including sources down to peak flux densities of five or
more times the local rms noise along with information on source sizes and
relevant pointing data. We discuss in some detail the consideration of whether
sources are resolved under the complication of a radio image created as a
mosaic of separate pointings each suffering some degree of bandwidth smearing,
and the accurate evaluation of the flux densities of such sources. Finally, the
radio morphologies and optical/near-IR counterpart identifications (Bonzini et
al. 2012) are used to identify 17 likely multiple-component sources and arrive
at a catalog of 883 radio sources, which is roughly double the number of
sources contained in the first data release.


title: The cone of Betti tables over a rational normal curve

abstract:
  We describe the cone of Betti tables of Cohen-Macaulay modules over the
homogeneous coordinate ring of a rational normal curve.


title: A Unified Community Detection, Visualization and Analysis method

abstract:
  Community detection in social graphs has attracted researchers' interest for
a long time. With the widespread of social networks on the Internet it has
recently become an important research domain. Most contributions focus upon the
definition of algorithms for optimizing the so-called modularity function. In
the first place interest was limited to unipartite graph inputs and partitioned
community outputs. Recently bipartite graphs, directed graphs and overlapping
communities have been investigated. Few contributions embrace at the same time
the three types of nodes. In this paper we present a method which unifies
commmunity detection for the three types of nodes and at the same time merges
partitionned and overlapping communities. Moreover results are visualized in
such a way that they can be analyzed and semantically interpreted. For
validation we experiment this method on well known simple benchmarks. It is
then applied to real data in three cases. In two examples of photos sets with
tagged people we reveal social networks. A second type of application is of
particularly interest. After applying our method to Human Brain Tractography
Data provided by a team of neurologists, we produce clusters of white fibers in
accordance with other well known clustering methods. Moreover our approach for
visualizing overlapping clusters allows better understanding of the results by
the neurologist team. These last results open up the possibility of applying
community detection methods in other domains such as data analysis with
original enhanced performances.

categories: cs.SI physics.data-an physics.soc-ph stat.OT


title: Pretending to factor large numbers on a quantum computer

abstract:
  Shor's algorithm for factoring in polynomial time on a quantum
computer\cite{Shor} gives an enormous advantage over all known classical
factoring algorithm. We demonstrate how to factor products of large prime
numbers using a compiled version of Shor's quantum factoring algorithm. Our
technique can factor all products of $p,q$ such that $p,q$ are unequal primes
greater than two, runs in constant time, and requires only two coherent qubits.
This illustrates that the correct measure of difficulty when implementing
Shor's algorithm is not the size of number factored, but the length of the
period found.


title: Double-slit vacuum polarisation effects in ultra-intense laser fields

abstract:
  The influence of the strong laser-driven vacuum on a propagating
electromagnetic probe wave has been studied in detail. We investigate two
scenarios comprising a focused probe laser beam passing through a region of
vacuum polarised by an ultra-intense laser field. By splitting this strong
field into two, separated, monochromatic Gaussian pulses counter-propagating in
a plane perpendicular to the probe field axis, we demonstrate a leading order
light-by-light diffraction effect that generates an interference pattern
reminiscent of the classic double-slit experiment. We calculate the total
number of probe photons diffracted as well as the number diffracted into
regions where the vacuum polarisation signal is higher than the probe
background. In addition, we calculate the induced ellipticity and polarisation
rotation in the probe beam and show how, in the realistic situation in which
the centres of the two strong fields are not exactly aligned, certain ranges of
beam separation and observation distance may actually lead to an increase over
the idealised case of a single strong laser beam.


title: Amending the Vafa-Witten Theorem

abstract:
  The strong version of the Vafa-Witten theorem is shown may not to hold
because the zero condensate from a direct computation of the order parameter is
found to be a result on the symmetric vacuum. The validity of the Vafa-Witten
theorem relies then on its weak version, that the Goldstone boson is absent in
vector-like gauge theories with vanishing \theta-angle. The existence of a
charged \rho-meson condensate, which violates electromagnetic gauge symmetry,
is consistent with this weak version of the Vafa-Witten theorem when applied to
strong magnetic fields in QCD.


title: Metal silicide/poly-Si Schottky diodes for uncooled microbolometers

abstract:
  Nickel silicide Schottky diodes formed on polycrystalline Si<P> films are
proposed as temperature sensors of monolithic uncooled microbolometer IR focal
plane arrays. Structure and composition of nickel silicide/polycrystalline
silicon films synthesized in a low-temperature process are examined by means of
transmission electron microscopy. The Ni silicide is identified as multi-phase
compound composed by 20 to 40% of Ni3Si, 30 to 60% of Ni2Si and 10 to 30% of
NiSi with probable minor content of NiSi2 at the silicide/poly-Si interface.
Rectification ratios of the Schottky diodes vary from ~100 to ~20 for the
temperature increasing from 22 to 70C; they exceed 1000 at 80K. A barrier of
~0.95 eV is found to control the photovoltage spectra at room temperature. A
set of barriers is observed in photo-emf spectra at 80K and attributed to the
Ni-silicide/poly-Si interface. Absolute values of temperature coefficients of
voltage and current are found to vary from 0.3 to 0.6%/K for forward biasing
and around 2.5%/K for reverse biasing of the diodes.


title:
Analysis of Determinations of the Distance between the Sun and the
  Galactic Center

abstract:
  The paper investigates the question of whether or not determinations of the
distance between the Sun and the Galactic center R0 are affected by the
so-called "bandwagon effect", leading to selection effects in published data
that tend to be close to expected values, as was suggested by some authors. It
is difficult to estimate numerically a systematic uncertainty in R0 due to the
bandwagon effect; however, it is highly probable that, even if widely accepted
values differ appreciably from the true value, the published results should
eventually approach the true value despite the bandwagon effect. This should be
manifest as a trend in the published R0 data: if this trend is statistically
significant, the presence of the bandwagon effect can be suspected in the data.
Fifty two determinations of R0 published over the last 20 years were analyzed.
These data reveal no statistically significant trend, suggesting they are
unlikely to involve any systematic uncertainty due to the bandwagon effect. At
the same time, the published data show a gradual and statistically significant
decrease in the uncertainties in the R0 determinations with time.


title: Lagrangian-Only Quantum Theory

abstract:
  Despite the importance of the path integral, there have been relatively few
attempts to look to the Lagrangian for a more realistic framework that might
underlie quantum theory. While such realism is not available for the standard
path integral or quantum field theory, a promising alternative is to only
consider field histories for which the Lagrangian density is always zero. With
this change, it appears possible to replace amplitudes with equally-weighted
probabilities. This paper demonstrates a proof-of-principle for this approach,
using a toy Lagrangian that corresponds to an arbitrary spin state. In this
restricted framework one can derive both the Born rule and its limits of
applicability. The fact that the Lagrangian obeys future boundary constraints
also results in the first continuous, spacetime-based, hidden-variable
description of a Bell-inequality-violating system.


title:
Regularized Transformation-Optics Cloaking for the Helmholtz Equation:
  From Partial Cloak to Full Cloak

abstract:
  We develop a very general theory on the regularized approximate invisibility
cloaking for the wave scattering governed by the Helmholtz equation in any
space dimensions via the approach of transformation optics.


title:
Bethe-Heitler type radiative corrections to deeply virtual
  neutrinoproduction of mesons

abstract:
  We study the electromagnetic Bethe-Heitler type contribution to
neutrino-induced deeply virtual meson production (\nuDVMP). Such
O(\alpha_{em})-corrections decrease with Q^{2} in the Bjorken regime less
steeply than the standard \nuDVMP handbag contribution. Therefore, they are
relatively enhanced at high Q^{2}. The Bethe-Heitler terms give rise to an
angular correlation between the lepton and hadron scattering planes with
harmonics sensitive to the real and imaginary parts of the DVMP amplitude.
These corrections constitute a few percent effect in the kinematics of the
forthcoming Minerva experiment at Fermilab and should be taken into account in
precision tests of GPD parametrizations. For virtualities Q^{2}~100 GeV^{2}
these corrections become on a par with DVMP handbag contributions. A
computational code, which can be used for the evaluation of these corrections
employing various GPD models is provided.


title: Mining Frequent Graph Patterns with Differential Privacy

abstract:
  Discovering frequent graph patterns in a graph database offers valuable
information in a variety of applications. However, if the graph dataset
contains sensitive data of individuals such as mobile phone-call graphs and
web-click graphs, releasing discovered frequent patterns may present a threat
to the privacy of individuals. {\em Differential privacy} has recently emerged
as the {\em de facto} standard for private data analysis due to its provable
privacy guarantee. In this paper we propose the first differentially private
algorithm for mining frequent graph patterns.
  We first show that previous techniques on differentially private discovery of
frequent {\em itemsets} cannot apply in mining frequent graph patterns due to
the inherent complexity of handling structural information in graphs. We then
address this challenge by proposing a Markov Chain Monte Carlo (MCMC) sampling
based algorithm. Unlike previous work on frequent itemset mining, our
techniques do not rely on the output of a non-private mining algorithm.
Instead, we observe that both frequent graph pattern mining and the guarantee
of differential privacy can be unified into an MCMC sampling framework. In
addition, we establish the privacy and utility guarantee of our algorithm and
propose an efficient neighboring pattern counting technique as well.
Experimental results show that the proposed algorithm is able to output
frequent patterns with good precision.


title: Vacuum condensates, flavor mixing and spontaneous supersymmetry breaking

abstract:
  Spontaneous supersymmetry (SUSY) breaking is revealed in all phenomena in
which vacuum condensates are physically relevant. The dynamical breakdown of
SUSY is generated by the condensates themselves, which lift the zero point
energy. Evidence is presented in the case of the Wess-Zuimino model, and the
flavor mixing case is treated in detail.


title: Random matrix minor processes related to percolation theory

abstract:
  This paper studies a number of matrix models of size n and the associated
Markov chains for the eigenvalues of the models for consecutive n's. They are
consecutive principal minors for two of the models, GUE with external source
and the multiple Laguerre matrix model, and merely properly defined consecutive
matrices for the third one, the Jacobi-Pineiro model; nevertheless the
eigenvalues of the consecutive models all interlace. We show: (i) For each of
those finite models, we give the transition probability of the associated
Markov chain and the joint distribution of the entire interlacing set of
eigenvalues; we show this is a determinantal point process whose extended
kernels share many common features. (ii) To each of these models and their set
of eigenvalues, we associate a last-passage percolation model, either finite
percolation or percolation along an infinite strip of finite width, yielding a
precise relationship between the last passage times and the eigenvalues. (iii)
Finally it is shown that for appropriate choices of exponential distribution on
the percolation, with very small means, the rescaled last passage times lead to
the Pearcey process; this should connect the Pearcey statistics with random
directed polymers.


title:
Model of coherent optical spin manipulation through hot trion states in
  p-doped InAs/GaAs quantum dots

abstract:
  A new generalised group-theoretical approach, based on master
Maxwell-pseudospin equations, is proposed to explain recently observed enhanced
circular dichroism in the excited state emission from p-doped quantum dot
ensembles under resonant circularly polarised excitation into hot trion states,
herein referred to as "spin-filtering effect". The theory agrees remarkably
well with polarised time-resolved photoluminescence experiments, yielding
largely unknown inter- and intra-shell spin relaxation time scales. This
approach allows to predict optimum pulse parameters for control of spin
dynamics, which will enable exploitation of the effect in all-optical
spin-based quantum technologies.


title: Ising Model of a Glass Transition

abstract:
  Numerical simulations by Tanaka and coworkers indicate that glass forming
systems of moderately polydisperse hard-core particles, in both two and three
dimensions, exhibit diverging correlation lengths. These correlations are
described by Ising-like critical exponents, and are associated with diverging,
Vogel-Fulcher-Tamann, structural relaxation times. Related simulations of
thermalized hard disks indicate that the curves of pressure versus packing
fraction for different polydispersities exhibit a sequence of transition
points, starting with a liquid-hexatic transition for the monodisperse case,
and crossing over with increasing polydispersity to glassy, Ising-like critical
points. I propose to explain these observations by assuming that glass-forming
fluids contain twofold degenerate, locally ordered clusters of particles,
similar to the two-state systems that have been invoked to explain other glassy
phenomena. This paper starts with a brief statistical derivation of the
thermodynamics of thermalized, hard-core particles. It then discusses how a
two-state, Ising-like model can be described within that framework in terms of
a small number of statistically relevant, internal state variables. The
resulting theory agrees accurately with the simulation data. I also propose a
rationale for the observed relation between the Ising-like correlation lengths
and the Vogel-Fulcher-Tamann formula.


title: The Star Formation Laws of Eddington-Limited Star-Forming Disks

abstract:
  Two important avenues into understanding the formation and evolution of
galaxies are the Kennicutt-Schmidt (KS) and Elmegreen-Silk (ES) laws. These
relations connect the surface densities of gas and star formation (\sigmagas\
and \sigmastar, respectively) in a galaxy. To elucidate the KS and ES laws for
disks where \sigmagas >~ 10^4 Msun pc-2}, we compute 132 Eddington-limited
star-forming disk models with radii spanning tens to hundreds of parsecs. The
theoretically expected slopes (approx. 1 for the KS law and approx. 0.5 for the
ES relation) are relatively robust to spatial averaging over the disks.
However, the star formation laws exhibit a strong dependence on opacity that
separates the models by the dust-to-gas ratio that may lead to the appearance
of a erroneously large slope. The total infrared luminosity (L_TIR) and
multiple carbon monoxide (CO) line intensities were computed for each model.
While L_TIR can yield an estimate of the average \sigmastar\ that is correct to
within a factor of 2, the velocity-integrated CO line intensity is a poor proxy
for the average \sigmagas\ for these warm and dense disks, making the CO
conversion factor (\alpha_CO) all but useless. Thus, observationally derived KS
and ES laws at these values of \sigmagas\ that uses any transition of CO will
provide a poor measurement of the underlying star formation relation. Studies
of the star formation laws of Eddington-limited disks will require a high-J
transition of a high density molecular tracer, as well as a sample of galaxies
with known metallicity estimates.


title:
Extracting quantum work statistics and fluctuation theorems by single
  qubit interferometry

abstract:
  We propose an experimental scheme to verify the quantum non-equilibrium
fluctuation relations using current technology. Specifically, we show that the
characteristic function of the work distribution for a non-equilibrium quench
of a general quantum system can be extracted from Ramsey interferometry of a
single probe qubit. Our scheme paves the way for the full characterisation of
non-equilibrium processes in a variety of complex quantum systems ranging from
single particles to many-body atomic systems and spin chains. We demonstrate
our idea using a time-dependent quench of the motional state of a trapped ion,
where the internal pseudo-spin provides a convenient probe qubit.


title: Anomalous diffusion of proteins in sheared lipid membranes

abstract:
  We use coarse grained molecular dynamics simulations to investigate diffusion
properties of sheared lipid membranes with embedded transmembrane proteins. In
membranes without proteins, we find normal in-plane diffusion of lipids in all
flow conditions. Protein embedded membranes behave quite differently: by
imposing a simple shear flow and sliding the monolayers of the membrane over
each other, the motion of protein clusters becomes strongly superdiffusive in
the shear direction. In such a circumstance, subdiffusion regime is predominant
perpendicular to the flow. We show that superdiffusion is a result of
accelerated chaotic motions of protein--lipid complexes within the membrane
voids, which are generated by hydrophobic mismatch or the transport of lipids
by proteins.


title: The Capacity of Adaptive Group Testing

abstract:
  We define capacity for group testing problems and deduce bounds for the
capacity of a variety of noisy models, based on the capacity of equivalent
noisy communication channels. For noiseless adaptive group testing we prove an
information-theoretic lower bound which tightens a bound of Chan et al. This
can be combined with a performance analysis of a version of Hwang's adaptive
group testing algorithm, in order to deduce the capacity of noiseless and
erasure group testing models.


title: From continued fractions and quadratic functions to modular forms

abstract:
  In this paper we study certain real functions defined in a very simple way by
Zagier as sums of infinite powers of quadratic polynomials with integer
coefficients. These functions give the even parts of the period polynomials of
the modular forms which are the coefficients in Fourier expansion of the kernel
function for Shimura-Shintani correspondence. We prove two conjectures of
Zagier showing that the sums converge exponentially. We also prove unexpected
results on the representation of these functions as sums over simple or reduced
quadratic forms and the positive or negative continued fraction of the
variable. These arise from more general results on polynomials of even degree.
Especially we give the even part of the Eichler integral on a real number x of
any cusp form for PSL(2,Z) in terms of the even part of its period polynomial
and the continued fraction of x.


title: Casimir probe based upon metallized high Q SiN nanomembrane resonator

abstract:
  We present the instrumentation and measurement scheme of a new Casimir force
probe that bridges Casimir force measurements at microscale and macroscale. A
metallized high Q silicon nitride nanomembrane resonator is employed as a
sensitive force probe. The high tensile stress present in the nanomembrane not
only enhances the quality factor but also maintains high flatness over large
area serving as the bottom electrode in a sphere-plane configuration. A fiber
interferometer is used to readout the oscillation of the nanomembrane and a
phase-locked loop scheme is applied to track the change of the resonance
frequency. Because of the high quality factor of the nanomembrane and the high
stability of the setup, a frequency resolution down to $2\times10^{-9}$ and a
corresponding force gradient resolution of 3 $\mu$N/m is achieved. Besides
sensitive measurement of Casimir force, our measurement technique
simultaneously offers Kelvin probe measurement capability that allows in situ
imaging of the surface potentials.


title: Prepivoting composite score statistics by weighted bootstrap iteration

abstract:
  The role played by the composite analogue of the log likelihood ratio in
hypothesis testing and in setting confidence regions is not as prominent as it
is in the canonical likelihood setting, since its asymptotic distribution
depends on the unknown parameter. Approximate pivots based on the composite log
likelihood ratio can be derived by using asymptotic arguments. However, the
actual distribution of such pivots may differ considerably from the asymptotic
reference, leading to tests and confidence regions whose levels are distant
from the nominal ones. The use of bootstrap rather than asymptotic
distributions in the composite likelihood framework is explored. Prepivoted
tests and confidence sets based on a suitable statistic turn out to be accurate
and computationally appealing inferential tools.


title:
Measurement of the 12C(e,e'p)11B Two-Body Breakup Reaction at High
  Missing Momentum Values

abstract:
  The five-fold differential cross section for the 12C(e,e'p)11B reaction was
determined over a missing momentum range of 200-400 MeV/c, in a kinematics
regime with Bjorken x > 1 and Q2 = 2.0 (GeV/c)2. A comparison of the results
and theoretical models and previous lower missing momentum data is shown. The
theoretical calculations agree well with the data up to a missing momentum
value of 325 MeV/c and then diverge for larger missing momenta. The extracted
distorted momentum distribution is shown to be consistent with previous data
and extends the range of available data up to 400 MeV/c.


title:
$(q;l,\lambda)-$deformed Heisenberg algebra: representations, special
  functions and quantization

abstract:
  This paper addresses a new characterization of Sudarshan's diagonal
representation of the density matrix elements $\rho(z',z)$, derivedfrom
$(q;l,\lambda)-$deformed boson coherent states.The induced $\rho(z',z)$
self-reproducing property with the associated self-reproducing kernel $K(z',z)$
is computed and analyzed. An explicit construction of novel classes of
generalized continuous $(q;l,\lambda)-$Hermite polynomials is provided with the
corresponding recursion relations and exact resolution of the moment problems
giving their orthogonality weight functions. Besides, the
Berezin-Klauder-Toeplitz quantization of classical phase space observables and
relevant normal and anti-normal forms are investigated and discussed.


title:
Holographic duals to Poisson sigma models and noncommutative quantum
  mechanics

abstract:
  Poisson sigma models are a very rich class of two-dimensional theories that
includes, in particular, all 2D dilaton gravities. By using the Hamiltonian
reduction method, we show that a Poisson sigma model (with a sufficiently
well-behaving Poisson tensor) on a finite cylinder is equivalent to a
noncommutative quantum mechanics for the boundary data.


title: Measuring the characteristic function of the work distribution

abstract:
  We propose an interferometric setting for the ancilla-assisted measurement of
the characteristic function of the work distribution following a time-dependent
process experienced by a quantum system. We identify how the configuration of
the effective interferometer is linked to the symmetries enjoyed by the
Hamiltonian ruling the process and provide the explicit form of the operations
to implement in order to accomplish our task. We finally discuss two physical
settings, based on hybrid opto-/electro-mechanical devices, where the
theoretical proposals discussed in our work could find an experimental
demonstration.


title:
Adaptive Reduced-Rank Constrained Constant Modulus Beamforming
  Algorithms Based on Joint Iterative Optimization of Filters

abstract:
  This paper proposes a robust reduced-rank scheme for adaptive beamforming
based on joint iterative optimization (JIO) of adaptive filters. The novel
scheme is designed according to the constant modulus (CM) criterion subject to
different constraints, and consists of a bank of full-rank adaptive filters
that forms the transformation matrix, and an adaptive reduced-rank filter that
operates at the output of the bank of filters to estimate the desired signal.
We describe the proposed scheme for both the direct-form processor (DFP) and
the generalized sidelobe canceller (GSC) structures. For each structure, we
derive stochastic gradient (SG) and recursive least squares (RLS) algorithms
for its adaptive implementation. The Gram-Schmidt (GS) technique is applied to
the adaptive algorithms for reformulating the transformation matrix and
improving performance. An automatic rank selection technique is developed and
employed to determine the most adequate rank for the derived algorithms. The
complexity and convexity analyses are carried out. Simulation results show that
the proposed algorithms outperform the existing full-rank and reduced-rank
methods in convergence and tracking performance.


title:
Design and Simulation of IOTA - a Novel Concept of Integrable Optics
  Test Accelerator

abstract:
  The use of nonlinear lattices with large betatron tune spreads can increase
instability and space charge thresholds due to improved Landau damping.
Unfortunately, the majority of nonlinear accelerator lattices turn out to be
nonintegrable, producing chaotic motion and a complex network of stable and
unstable resonances. Recent advances in finding the integrable nonlinear
accelerator lattices have led to a proposal to construct at Fermilab a test
accelerator with strong nonlinear focusing which avoids resonances and chaotic
particle motion. This presentation will outline the main challenges,
theoretical design solutions and construction status of the Integrable Optics
Test Accelerator underway at Fermilab.


title:
Quantum Hall Effect in Fractal Graphene: Growth and Properties of
  Graphlocons

abstract:
  Highly dendritic graphene crystals up to 0.25 mm in diameter are synthesized
by low pressure chemical vapor deposition inside a copper enclosure. With their
sixfold symmetry and fractal-like shape, the crystals resemble snowflakes. The
evolution of the dendritic growth features is investigated for different growth
conditions and surface diffusion is found to be the growth-limiting step
responsible for the formation of dendrites. The electronic properties of the
dendritic crystals are examined down to sub-Kelvin temperatures, showing a
mobility of up to 6300 cm$^2$V$^{-1}$s$^{-1}$ and quantum Hall oscillations are
observed above 4T. These results demonstrate the high quality of the transport
properties despite their rough dendritic edges.


title: On the free time minimizers of the Newtonian N-body problem

abstract:
  In this paper we study the existence and the dynamics of a very special class
of motions, which satisfy a strong global minimization property. More
precisely, we call a free time minimizer a curve which satisfies the least
action principle between any pair of its points without the constraint of time
for the variations. An example of a free time minimizer defined on an unbounded
interval is a parabolic homothetic motion by a minimal central confguration.
The existence of a large amount of free time minimizers can be deduced from the
weak KAM theorem. In particular, for any choice of x0, there should be at least
one free time minimizer x(t) defined for all positive time and satisfying
x(0)=x0. We prove that such motions are completely parabolic. Using Marchal's
theorem we deduce as a corollary that there are no entire free time minimizers,
i.e. defined on R. This means that the Ma\~n\'e set of the Newtonian N-body
problem is empty.


title: From adiabatic piston to non-equilibrium hydrodynamics

abstract:
  Based on the new concept of the {\it momentum transfer deficiency due to
dissipation} (MDD), the physical basis of the mechanism of ``adiabatic piston''
is explained. The implication of MDD in terms of hydrodynamics under
non-equilibrium steady state also discussed.


title: Uncertainty, incompleteness, chance, and design

abstract:
  The 20th century has revealed two important limitations of scientific
knowledge. On the one hand, the combination of Poincar\'e's nonlinear dynamics
and Heisenberg's uncertainty principle leads to a world picture where physical
reality is, in many respects, intrinsically undetermined. On the other hand,
G\"odel's incompleteness theorems reveal us the existence of mathematical
truths that cannot be demonstrated. More recently, Chaitin has proved that,
from the incompleteness theorems, it follows that the random character of a
given mathematical sequence cannot be proved in general (it is 'undecidable').
I reflect here on the consequences derived from the indeterminacy of the future
and the undecidability of randomness, concluding that the question of the
presence or absence of finality in nature is fundamentally outside the scope of
the scientific method.


title:
Remarks on local symmetry invariance in perturbative algebraic quantum
  field theory

abstract:
  We investigate various aspects of invariance under local symmetries in the
framework of perturbative algebraic quantum field theory (pAQFT). Our main
result is the proof that the quantum Batalin-Vilkovisky (BV) operator,
on-shell, can be written as the commutator with the interacting BRST charge. Up
to now, this was proven only for a certain class of fields in quantum
electrodynamics and in Yang-Mills theory. Our result is more general and it
holds in a wide class of theories with local symmetries, including general
relativity and the bosonic string. We also comment on other issues related to
local gauge invariance and, using the language of homological algebra, we
compare different approaches to quantization of gauge theories in the pAQFT
framework.


title: A matterless double slit

abstract:
  Double-slits provide incoming photons with a choice. Those that survive the
passage have chosen from two possible paths which interfere to distribute them
in a wave-like manner. Such wave-particle duality continues to be challenged
and investigated in a broad range of disciplines with electrons, neutrons,
helium atoms, C60 fullerenes, Bose-Einstein condensates and biological
molecules. All variants have hitherto involved material constituents. We
present a matterless double-slit scenario in which photons generated from
virtual electron-positron pair annihilation in head-on collisions of a probe
laser field with two ultra-intense laser beams form a double-slit interference
pattern. Such electromagnetic fields are predicted to induce material-like
behaviour in the vacuum, supporting elastic scattering between photons. Our
double-slit scenario presents on the one hand a realisable method to observe
photon-photon scattering, and demonstrates on the other, the possibility of
both controlling light with light and non-locally investigating features of the
quantum vacuum's structure.


title:
The Six-Cavity Test - Demonstrated Acceleration of Beam with Multiple RF
  Cavities and a Single Klystron

abstract:
  The High Intensity Neutrino Source (HINS) Six-Cavity Test has demonstrated
the use of high power RF vector modulators to control multiple RF cavities
driven by a single high power klystron to accelerate a non-relativistic beam.
Installation of 6 cavities in the existing HINS beamline has been completed and
beam measurements have started. We present data showing the energy stability of
the 7 mA proton beam accelerated through the six cavities from 2.5 MeV to 3.4
MeV.


title:
Positive temperature versions of two theorems on first-passage
  percolation

abstract:
  The estimates on the fluctuations of first-passsage percolation due to
Talagrand (a tail bound) and Benjamini--Kalai--Schramm (a sublinear variance
bound) are transcribed into the positive-temperature setting of random
Schroedinger operators.


title: The imaginary part of the gravity action and black hole entropy

abstract:
  As observed recently in arXiv:1212.2922, the action of General Relativity
(GR) in finite spacetime regions has an imaginary part that resembles the
Bekenstein entropy. In this paper, we expand on that argument, with attention
to different causal types of boundaries. This property of the GR action may
open a new approach to the puzzles of gravitational entropy. In particular, the
imaginary action can be evaluated for non-stationary finite regions, where the
notion of entropy is not fully understood. As a first step in constructing the
precise relationship between the imaginary action and entropy, we focus on
stationary black hole spacetimes. There, we identify a class of bounded regions
for which the action's imaginary part precisely equals the black hole entropy.
As a powerful test on the validity of the approach, we also calculate the
imaginary action for Lovelock gravity. The result is related to the
corresponding entropy formula in the same way as in GR.


title: Neutrino Pair Emission from Hot Nuclei During Stellar Collapse

abstract:
  We present shell-model calculations showing that residual interaction-induced
configuration mixing enhances the rate of neutral current de-excitation of
thermally excited nuclei into neutrino-antineutrino pairs. Though our
calculations reinforce the conclusions of previous studies that this process is
the dominant source of neutrino pairs near the onset of neutrino trapping
during stellar collapse, our shell-model result has the effect of increasing
the energy of these pairs, possibly altering their role in entropy transport in
supernovae.


title:
On the Basis Property of the Root Functions of Some Class of
  Non-self-adjoint Sturm--Liouville Operators

abstract:
  We obtain the asymptotic formulas for the eigenvalues and eigenfunctions of
the Sturm-Liouville operators with some regular boundary conditions. Using
these formulas, we find sufficient conditions on the potential q such that the
root functions of these operators do not form a Riesz basis.


title:
A WFC3/HST view of the three stellar populations in the Globular Cluster
  NGC6752

abstract:
  Multi-band Hubble Space Telescope photometry reveals that the main sequence,
sub-giant, and the red giant branch of the globular cluster NGC6752 splits into
three main components in close analogy with the three distinct segments along
its horizontal branch stars. These triple sequences are consistent with three
stellar groups: a stellar population with a chemical composition similar to
field halo stars (population a), a population (c) with enhanced sodium and
nitrogen, depleted carbon and oxygen and enhanced helium abundance (Delta Y
~0.03), and a population (b) with an intermediate (between population a and c)
chemical composition and slightly helium enhanced (Delta Y ~0.01). These
components contain ~25% (population a), ~45% (population b), and ~30%
(population c) of the stars. No radial gradient for the relative numbers of the
three populations has been identified out to about 2.5 half mass radii.


title: Extremal K\"ahler metrics on projectivised vector bundles

abstract:
  We prove the existence of extremal, non-csc, K\"ahler metrics on certain
unstable projectivised vector bundles $\P (E) \to M$ over a cscK-manifold $M$
with discrete holomorphic automorphism group, in certain adiabatic K\"ahler
classes. In particular, the vector bundles $E \to M$ under consideration are
assumed to split as a direct sum of stable subbundles $E=E_1 \oplus \dots
\oplus E_s$ all having different Mumford-Takemoto-slope, e.g. $\mu(E_1) > \dots
> \mu(E_s)$.


title:
Outer Bound of the Capacity Region for Identification via Multiple
  Access Channels

abstract:
  In this paper we consider the identification (ID) via multiple access
channels (MACs). In the general MAC the ID capacity region includes the
ordinary transmission (TR) capacity region. In this paper we discuss the
converse coding theorem. We estimate two types of error probabilities of
identification for rates outside capacity region, deriving some function which
serves as a lower bound of the sum of two error probabilities of
identification. This function has a property that it tends to zero as $n\to
\infty$ for noisy channels satisfying the strong converse property. Using this
property, we establish that the transmission capacity region is equal to the ID
capacity for the MAC satisfying the strong converse property. To derive the
result we introduce a new resolvability problem on the output from the MAC. We
further develop a new method of converting the direct coding theorem for the
above MAC resolvability problem into the converse coding theorem for the ID via
MACs.


title: Link prediction for partially observed networks

abstract:
  Link prediction is one of the fundamental problems in network analysis. In
many applications, notably in genetics, a partially observed network may not
contain any negative examples of absent edges, which creates a difficulty for
many existing supervised learning approaches. We develop a new method which
treats the observed network as a sample of the true network with different
sampling rates for positive and negative examples. We obtain a relative ranking
of potential links by their probabilities, utilizing information on node
covariates as well as on network topology. Empirically, the method performs
well under many settings, including when the observed network is sparse. We
apply the method to a protein-protein interaction network and a school
friendship network.


title:
Search for $B_s \rightarrow \mu^{+}\mu^{-}$ and $B_d \rightarrow
  \mu^{+}\mu^{-}$ decays with the full CDF Run II data set

abstract:
  We report on a search for \bsmm\ and \bdmm\ decays using proton-antiproton
collision data at $\sqrt{s}=1.96$ TeV corresponding to $10 \fb$ of integrated
luminosity collected by the CDF detector at the Fermilab Tevatron collider. The
observed number of \bd\ candidates is consistent with background-only
expectations and yields an upper limit on the branching fraction of $\brbdmm <
4.6\times 10^{-9}$ at 95% confidence level. We observe an excess of \bs\
candidates. The probability that the background processes alone could produce
such an excess or larger is 0.94%. The probability that the combination of
background and the expected standard model rate of \bsmm\ could produce such an
excess or larger is 6.8%. These data are used to determine a branching fraction
$\brbsmm = (1.3^{+0.9}_{-0.7}) \times 10^{-8} $ and provide an upper limit of
$\brbsmm < 3.1\times 10^{-8}$ at 95% confidence level.


title:
Modeling the Nuclear Infrared Spectral Energy Distribution of Type II
  Active Galactic Nuclei

abstract:
  We present results from model fitting to the Spectral Energy Distribution
(SED) of a homogeneous sample of Seyfert II galaxies drawn from the $12\mu$m
Galaxy Sample. Imaging and nuclear flux measurements are presented in an
accompanying paper (Videla et al., 2013). Here we add IRS Spitzer observations
to further constrain the SEDs after careful subtraction of a starburst
component. We use the library of CLUMPY torus models from Nenkova et
al.~(2008ab) and also test the two-phase models recently produced by Stalevski
et al.~(2012). We find that photometric and spectroscopic observations in the
mid-IR (>5mu) are crucial to properly constrain the best-fit torus models.
About half of our sources show clear near-IR excess of their SEDs above the
best fit models. This problem can be less severe when using the Stalevski et
al.~(2012) models. It is not clear what is the nature of this emission since
best fitted black body temperatures are very high (~1700-2500 K) and the Type
II classification of our sources would correspond to a small probability to
peer directly into the hottest regions of the torus. Crucially, the derived
torus parameters when using CLUMPY models are quite robust,, independently of
whether the sources require an additional black body component or not. Our
findings suggest that tori are characterized by N_0 > 5, sigma > 40, tau < 25,
i > 40 degrees, Y < 50 and A_v^los ~ 100-300. From these we can determine that
typical torus sizes and masses of 0.1-5.0 pc and 10^{4-6} M_\odot. We find
tentative evidence that those nuclei with a detected Hidden Broad Line Regions
are characterized by lower levels of extinction than those without one.
Finally, we find no correlation between the torus properties and the presence
of circumnuclear or more global star-formation.


title: (Strongly) $M-\pazocal{A}-$Injective(Flat) Modules

abstract:
  Let $M$ be a left $R-$module and $\pazocal{A}=\{A\}_{A\in\pazocal{A}}$ be a
family of some submodules of $M$. It is introduced the classes of (strongly)
$M-\pazocal{A}-\mathrm{injective}$ and (strongly) $M-\pazocal{A}-\mathrm{flat}$
modules which are denoted by $(S) M-\pazocal{A}I$ and $(S) M-\pazocal{A}F$,
respectively. It is obtained some characterizations of these classes and the
relationships between these classes. Moreover it is investigated $(S)
M-\pazocal{A}I$ and $(S) M-\pazocal{A}F$ precovers and preenvelopes of modules.
It is also studied $\pazocal{A}$-coherent, $F\pazocal{A}$ and $P\pazocal{A}$
modules. Finally more generally we give the characterization of
$S-\pazocal{A}I(F)$ modules where $\pazocal{A}=\{A\}_{A\in\pazocal{A}}$ is a
family of some left $R-$modules.


title:
On radiation reaction and the [x,p ] commutator for an accelerating
  charge

abstract:
  We formally state the connection between the relativistic part of the
radiation reaction and the Poynting Robertson force term, $-Rv/c^2$, where $R$
is power radiated. Then we address the question, does $[x,p]=i \hb$ for an
accelerating charge ? The full radiation reaction term is used, which includes
the relativistic term (von Laue vector.). We show that the full relativistic
radiation reaction term must be taken into account if a commutation relation
between $x$ and $p$ is to hold for an electron under uniform acceleration,
consistent with the expectation values of $x^2$ and $p^2$.


title: Classification of affine vortices

abstract:
  We prove a Hitchin-Kobayashi correspondence for affine vortices generalizing
a result of Jaffe-Taubes for the action of the circle on the affine line.
Namely, suppose a compact Lie group K has a Hamiltonian action on a Kaehler
manifold X which is either compact or convex at infinity with a proper moment
map, and so that stable=semistable for the action of the complexified Lie group
G. Then, for some sufficiently divisible integer n, there is a bijection
between gauge equivalence classes of K-vortices with target X modulo gauge and
isomorphism classes of maps from the weighted projective line P(1,n) to X/G
that map the stacky point at infinity P(n) to the semistable locus in X. The
results allow the construction and partial computation of the quantum Kirwan
map in Woodward, and play a role in the conjectures of Dimofte, Gukov, and
Hollande relating vortex counts to knot invariants.


title:
Delayed Twin Observables Are They a Fundamental Concept in Quantum
  Mechanics?

abstract:
  Opposite-subsystem twin events and twin observables, studied previously in
the context of distant correlations, are first generalized to pure states of
not-necessarily-composite systems, and afterwards they are further generalized
to delayed twins that are due to unitary evolution of the quantum system. The
versatile aspects of delayed twin observables are studied in terms of necessary
and sufficient conditions to make possible various applications. Three of these
are sketched: Preparation of some quantum experiments, easy solution of a
puzzle in an important Scully et al. real experiment, and, finally, it is shown
that exact measurement in quantum mechanics is an example of opposite-subsystem
delayed twins in bipartite pure states.


title: Repair for Distributed Storage Systems with Erasure Channels

abstract:
  We study the repair problem of distributed storage systems in erasure
networks where the packets transmitted from surviving nodes to the new node
might be lost. The fundamental storage-bandwidth tradeoff is calculated by
multicasting analysis in erasure networks. The optimal tradeoff bound can be
asymptotically achieved when the number of transmission (packets) goes to
infinity. For a limited number of transmission, we study the probability of
successful regenerating. Then, we investigate two approaches of increasing the
probability of successful regenerating, namely, by connecting more surviving
nodes or by increasing the storage space of nodes. Using more nodes may pose
larger delay and in certain situation it might not be possible to connect to
more nodes too. We show that in addition to reducing repair bandwidth,
increasing storage space can also increase reliability for repair.


title:
Was the GLE on May 17, 2012 linked with the M5.1-class flare the first
  in the 24th solar cycle?

abstract:
  On May 17, 2012 an M5.1-class flare exploded from the sun. An O-type coronal
mass ejection (CME) was also associated with this flare. There was an instant
increase in proton flux with peak at $\geq 100$ MeV, leading to S2 solar
radiation storm level. In about 20 minutes after the X-ray emission, the solar
particles reached the Earth.It was the source of the first (since December
2006) ground level enhancement (GLE) of the current solar cycle 24. The GLE was
detected by neutron monitors (NM) and other ground based detectors. Here we
present an observation by the Tupi muon telescopes (Niteroi, Brazil, $22^{0}.9
S$, $43^{0}.2 W$, 3 m above sea level) of the enhancement of muons at ground
level associated with this M5.1-class solar flare. The Tupi telescopes
registered a muon excess over background $\sim 20\%$ in the 5-min binning time
profile. The Tupi signal is studied in correlation with data obtained by
space-borne detectors (GOES, ACE), ground based neutron monitors (Oulu) and air
shower detectors (the IceTop surface component of the IceCube neutrino
observatory). We also report the observation of the muon signal possibly
associated with the CME/sheath striking the Earth magnetosphere on May 20,
2012. We show that the observed temporal correlation of the muon excess
observed by the Tupi muon telescopes with solar transient events suggests a
real physical connection between them. Our observation indicates that
combination of two factors, the low energy threshold of the Tupi muon
telescopes and the location of the Tupi experiment in the South Atlantic
Anomaly region, can be favorable in the study and detection of the solar
transient events. Our experiment provides new data complementary to other
techniques (space and ground based) in the study of solar physics.


title: A beginner's introduction to Fukaya categories

abstract:
  The goal of these notes is to give a short introduction to Fukaya categories
and some of their applications. The first half of the text is devoted to a
brief review of Lagrangian Floer (co)homology and product structures. Then we
introduce the Fukaya category (informally and without a lot of the necessary
technical detail), and briefly discuss algebraic concepts such as exact
triangles and generators. Finally, we mention wrapped Fukaya categories and
outline a few applications to symplectic topology, mirror symmetry and
low-dimensional topology. This text is based on a series of lectures given at a
Summer School on Contact and Symplectic Topology at Universit\'e de Nantes in
June 2011.


title:
Some integral inequalities for {\alpha}-, m-,
  ({\alpha},m)-logarithmically convex functions

abstract:
  In this paper, we establish some new Hadamard type inequalities using
elementary well known inequalities for functions whose inequalities absolute
values are {\alpha}-, m-, ({\alpha},m)-logarithmically convex.


title: Spot it(R) Solitaire

abstract:
  The game of Spot it(R) is based on an order 7 finite projective plane. This
article presents a solitaire challenge: extract an order 7 affine plane and
arrange those 49 cards into a square such that the symmetries of the affine and
projective planes are obvious. The objective is not to simply create such a
deck already in this solved position. Rather, it is to solve the inverse
problem of arranging the cards of such a deck which has already been created
shuffled.


title: Morita equivalences and Azumaya loci from Higgsing dimer algebras

abstract:
  Let $\psi: A \to A'$ be a cyclic contraction of dimer algebras, with $A$
non-cancellative and $A'$ cancellative. $A'$ is then prime, noetherian, and a
finitely generated module over its center. In contrast, $A$ is often not prime,
nonnoetherian, and an infinitely generated module over its center. We present
certain Morita equivalences that relate the representation theory of $A$ with
that of $A'$.
  We then characterize the Azumaya locus of $A$ in terms of the Azumaya locus
of $A'$, and give an explicit classification of the simple $A$-modules
parameterized by the Azumaya locus. Furthermore, we show that if the smooth and
Azumaya loci of $A'$ coincide, then the smooth and Azumaya loci of $A$
coincide. This provides the first known class of algebras that are
nonnoetherian and infinitely generated modules over their centers, with the
property that their smooth and Azumaya loci coincide.


title:
INTEGRAL observations of Sco X-1: evidence for Comptonization up to 200
  keV

abstract:
  We have analyzed a long-term database for Sco X-1 obtained with the telescope
IBIS onboard the INTEGRAL satellite in order to study the hard X-ray behavior
of Sco X-1 from 20 up to 200 keV. Besides the data used for producing of the
INTEGRAL catalog of sources, this is the longest (412 ks) database of IBIS on
Sco X-1 up to date. The production of hard X-ray tails in low-mass X-ray
binaries is still a matter of debate. Since most of the fits to the high-energy
part of the spectra are done with powerlaw models, the physical mechanism for
the hard X-ray tail production is unclear. The purpose of this study is to
better constrain those possible mechanisms. Our main result shows a strong
correlation between the fluxes in the thermal and nonthermal part of Sco X-1
spectra. We thus suggest that Comptonization of lower energy photons is the
mechanism for producing hard X-ray tails in Sco X-1.


title:
Quantum discord and its geometric measure with death entanglement in
  correlated dephasing two qubits system

abstract:
  The quantum correlations, including entanglement and discord with its
geometric measure, and classical correlation are studied for a bipartite
partition of a open or closed quantum system. It is found that the purity of
the initial state plays an important role in the dynamics of quantum and
classical correlations. In the dephasing model, the quantum correlations loss
and the classical correlation gain are instantaneously happen. While, the
purity of the initial state destroys the quantum correlations which is resulted
by the unitary interaction. Therefore, with the purity parameter, a particular
region in which there is no state have quantum correlations can be determined.


title: Emergent D4-Brane Background from D-Particles

abstract:
  We show that the solution of a pre-geometric strongly coupled quantum
mechanical model describing K D-particles in the presence of N D4-branes in
type IIA string theory, at fixed K and large N, yields an effective action
describing the motion of the K D-particles in a classical ten-dimensional
curved space-time. By comparing the effective action with the non-abelian
D-brane action in an arbitrary supergravity background, we identify the metric,
dilaton and Ramond-Ramond fields and find a precise match with the near-horizon
D4-brane geometry.


title:
What Are the Progenitors of Compact, Massive, Quiescent Galaxies at
  z=2.3? The Population of Massive Galaxies at z>3 from NMBS and CANDELS

abstract:
  [Abridged] Using public data from the NMBS and CANDELS surveys, we study the
population of massive galaxies at z>3 to identify the potential progenitors of
z~2 compact, massive, quiescent (CMQ) galaxies, furthering our understanding of
the evolution of massive galaxies. Our work is enabled by high-resolution
CANDELS images and accurate photometric redshifts, stellar masses and star
formation rates (SFRs) from 37-band NMBS photometry. The total number of z>3
massive galaxies is consistent with the number of massive quiescent (MQ)
galaxies at z~2, implying that the SFRs for all of these galaxies must be much
lower by z~2. We discover 4 CMQ galaxies at z>3, pushing back the time for
which such galaxies have been observed. However, the volume density for these
galaxies is significantly less than that of galaxies at z<2 with similar
masses, SFRs, and sizes, implying that additional CMQ galaxies must be created
in the ~1 Gyr between z=3 and z=2. We find 5 star-forming galaxies at z~3 that
are compact (Re<1.4 kpc) and have stellar mass M*>10^(10.6)Msun, likely to
become members of the CMQ galaxy population at z~2. We evolve the stellar
masses and SFRs of each individual z>3 galaxy adopting 5 different star
formation histories (SFHs) and studying the resulting population of massive
galaxies at z=2.3. We find that declining or truncated SFHs are necessary to
match the observed number density of MQ galaxies at z~2, whereas a constant SFH
results in a number density significantly smaller than observed. All of our
assumed SFHs imply number densities of CMQ galaxies at z~2 that are consistent
with the observed number density. Better agreement with the observed number
density of CMQ galaxies at z~2 is obtained if merging is included in the
analysis and better still if star formation quenching is assumed to shortly
follow the merging event, as implied by recent models of formation of MQ
galaxies.


title: How to Scale a Code in the Human Dimension

abstract:
  As scientists' needs for computational techniques and tools grow, they cease
to be supportable by software developed in isolation. In many cases, these
needs are being met by communities of practice, where software is developed by
domain scientists to reach pragmatic goals and satisfy distinct and enumerable
scientific goals. We present techniques that have been successful in growing
and engaging communities of practice, specifically in the yt and Enzo
communities.


title:
Quark-Lepton Mass Relation in a Realistic A4 Extension of the Standard
  Model

abstract:
  We propose a realistic A4 extension of the Standard Model involving a
particular quark-lepton mass relation, namely that the ratio of the third
family mass to the geometric mean of the first and second family masses are
equal for down-type quarks and charged leptons. This relation, which is
approximately renormalization group invariant, is usually regarded as arising
from the Georgi-Jarlskog relations, but in the present model there is no
unification group or supersymmetry. In the neutrino sector we propose a simple
modification of the so called Zee-Wolfenstein mass matrix pattern which allows
an acceptable reactor angle along with a deviation of the atmospheric and solar
angles from their bi-maximal values. Quark masses, mixing angles and CP
violation are well described by a numerical fit.


title:
The impact of a non-universal Initial Mass Function on the Star
  Formation Histories of Early-Type Galaxies

abstract:
  Recent results on the non-universality of the Initial Mass Function (IMF)
have shown strong evidence of IMF variations with galaxy velocity dispersion,
with a corresponding impact on other stellar population parameters, line
indices and colours. Using a set of stellar population models with varying IMF
slopes, we provide additional caveats on the assumption of a universal IMF. The
present study shows that the derived star formation histories of early-type
galaxies vary significantly with the IMF slope. For instance, a steepening in
the slope of a single power-law IMF decreases substantially, by a factor of up
to four, the contribution of the old stellar populations to the total
light/mass. This trend is milder for a segmented-like IMF shape, where the
contribution of the very low mass stars is decreased. It is also shown that, by
tuning each IMF slope to its prescribed value according to each galaxy velocity
dispersion, a sample of early-type galaxies covering a range of masses yield
comparable star formation histories. On the one hand, a small contribution from
relatively young stellar populations appear in the star formation histories of
most massive elliptical galaxies when adopting a steep IMF. On the other hand,
we find that low mass early-type galaxies that look like genuinely young
objects with a standard IMF (i.e. ``baby elliptical galaxies``), turn out to be
older when a slightly flatter IMF is employed. In summary, the use of a
non-universal IMF, tuned according to the velocity dispersion of the galaxy,
seems to provide more consistent results.


title:
First Measurement of the Muon Anti-Neutrino Double-Differential Charged
  Current Quasi-Elastic Cross Section

abstract:
  The largest sample ever recorded of $\numub$ charged-current quasi-elastic
(CCQE, $\numub + p \to \mup + n$) candidate events is used to produce the
minimally model-dependent, flux-integrated double-differential cross section
$\frac{d^{2}\sigma}{dT_\mu d\uz}$ for $\numub$ incident on mineral oil. This
measurement exploits the unprecedented statistics of the MiniBooNE
anti-neutrino mode sample and provides the most complete information of this
process to date. Also given to facilitate historical comparisons are the
flux-unfolded total cross section $\sigma(E_\nu)$ and single-differential cross
section $\frac{d\sigma}{d\qsq}$ on both mineral oil and on carbon by
subtracting the $\numub$ CCQE events on hydrogen. The observed cross section is
somewhat higher than the predicted cross section from a model assuming
independently-acting nucleons in carbon with canonical form factor values. The
shape of the data are also discrepant with this model. These results have
implications for intra-nuclear processes and can help constrain signal and
background processes for future neutrino oscillation measurements.


title:
Algebraically special perturbations of the Schwarzschild solution in
  higher dimensions

abstract:
  We study algebraically special perturbations of a generalized Schwarzschild
solution in any number of dimensions. There are two motivations. First, to
learn whether there exist interesting higher-dimensional algebraically special
solutions beyond the known ones. Second, algebraically special perturbations
present an obstruction to the unique reconstruction of general metric
perturbations from gauge-invariant variables analogous to the Teukolsky scalars
and it is desirable to know the extent of this non-uniqueness. In four
dimensions, our results generalize those of Couch and Newman, who found
infinite families of time-dependent algebraically special perturbations. In
higher dimensions, we find that the only regular algebraically special
perturbations are those corresponding to deformations within the Myers-Perry
family. Our results are relevant for several inequivalent definitions of
"algebraically special".


title: Precession of the Sagittarius stream

abstract:
  Using a variety of stellar tracers -- blue horizontal branch stars,
main-sequence turn-off stars and red giants -- we follow the path of the
Sagittarius (Sgr) stream across the sky in Sloan Digital Sky Survey data. Our
study presents new Sgr debris detections, accurate distances and line-of-sight
velocities that together help to shed new light on the puzzle of the Sgr tails.
For both the leading and the trailing tail, we trace the points of their
maximal extent, or apo-centric distances, and find that they lie at $R^L$ =
47.8 $\pm$ 0.5 kpc and $R^T$ = 102.5 $\pm$ 2.5 kpc respectively. The angular
difference between the apo-centres is 93.2 $\pm$ 3.5 deg, which is smaller than
predicted for logarithmic haloes. Such differential orbital precession can be
made consistent with models of the Milky Way in which the dark matter density
falls more quickly with radius. However, currently, no existing Sgr disruption
simulation can explain the entirety of the observational data. Based on its
position and radial velocity, we show that the unusually large globular cluster
NGC 2419 can be associated with the Sgr trailing stream. We measure the
precession of the orbital plane of the Sgr debris in the Milky Way potential
and show that, surprisingly, Sgr debris in the primary (brighter) tails evolves
differently to the secondary (fainter) tails, both in the North and the South.


title: Sagittarius stream 3-d kinematics from SDSS Stripe 82

abstract:
  Using multi-epoch observations of the Stripe 82 region done by Sloan Digital
Sky Survey, we measure precise statistical proper motions of the stars in the
Sagittarius stellar stream. The multi-band photometry and SDSS radial
velocities allow us to efficiently select Sgr members and thus enhance the
proper motion precision to ~0.1 mas/yr. We measure separately the proper motion
of a photometrically selected sample of the main sequence turn-off stars, as
well as of a spectroscopically selected Sgr giants. The data allow us to
determine the proper motion separately for the two Sgr streams in the South
found in Koposov et al.(2012). Together with the precise velocities from SDSS,
our proper motion provide exquisite constraints of the 3-D motions of the stars
in the Sgr streams.


title: Antibranes don't go black

abstract:
  When D-branes are inserted in flux backgrounds of opposite charge, the
resulting solution has a certain singularity in the fluxes. Recently it has
been argued, using numerical solutions, that for anti-D3 branes in the
Klebanov-Strassler background these singularities cannot be cloaked by a
horizon, which strongly suggests they are not physical. In this note we provide
an analytic proof that the singularity of all codimension-three antibrane
solutions (such as anti-D6 branes in massive type IIA supergravity or anti-D3
branes smeared on the T^3 of R^3xT^3 with fluxes) cannot be hidden behind a
horizon, and that the charge of black branes with smooth event horizons must
have the same sign as the charge of the flux background. Our result indicates
that infinitesimally blackening the antibranes immediately triggers brane-flux
annihilation, and strengthens the intuition that antibranes placed in flux with
positive charge immediately annihilate against it.


title: QCD as a topologically ordered system

abstract:
  We argue that QCD belongs to a topologically ordered phase similar to many
well-known condensed matter systems with a gap such as topological insulators
or superconductors. Our arguments are based on an analysis of the so-called
"deformed QCD" which is a weakly coupled gauge theory, but nevertheless
preserves all the crucial elements of strongly interacting QCD, including
confinement, nontrivial $\theta$ dependence, degeneracy of the topological
sectors, etc. Specifically, we construct the so-called topological "BF" action
which reproduces the well known infrared features of the theory such as
non-dispersive contribution to the topological susceptibility which can not be
associated with any propagating degrees of freedom. Furthermore, we interpret
the well known resolution of the celebrated $U(1)_A$ problem where the would be
$\eta'$ Goldstone boson generates its mass as a result of mixing of the
Goldstone field with a topological auxiliary field characterizing the system.
We then identify the non-propagating auxiliary topological field of the BF
formulation in deformed QCD with the Veneziano ghost (which plays the crucial
role in resolution of the $U(1)_A$ problem). Finally, we elaborate on relation
between "string -net" condensation in topologically ordered condensed matter
systems and long range coherent configurations, the "skeletons", studied in QCD
lattice simulations.

categories: hep-ph cond-mat.str-el hep-lat hep-th nucl-th


title: Fully stable dS vacua from generalised fluxes

abstract:
  We investigate the possible existence of (meta-)stable de Sitter vacua within
N=1 compactifications with generalised fluxes. With the aid of an algorithm
inspired by the method of differential evolution, we were able to find three
novel examples of completely tachyon-free de Sitter extrema in a non-isotropic
type IIB model with non-geometric fluxes. We also analyse the surroundings of
the aforementioned points in parameter space and chart the corresponding
stability regions. These happen to occur at small values of the cosmological
constant compared to the AdS scale.


title:
Gravitational and electromagnetic outputs from binary neutron star
  mergers

abstract:
  The late stage of an inspiraling neutron star binary gives rise to strong
gravitational wave emission due to its highly dynamic, strong gravity.
Moreover, interactions between the stellar magnetospheres can produce
considerable electromagnetic radiation. We study this scenario using fully
general relativistic, resistive magneto-hydrodynamics simulations. We show that
these interactions extract kinetic energy from the system, dissipate heat, and
power radiative Poynting flux, as well as develop current sheets. Our results
indicate that this power can: (i) outshine pulsars in binaries, (ii) display a
distinctive angular- and time-dependent pattern, and (iii) radiate within large
opening angles. These properties suggest that some binary neutron star mergers
are ideal candidates for multimessenger astronomy.


title:
Blow-up dynamics of self-attracting diffusive particles driven by
  competing convexities

abstract:
  In this paper, we analyze the dynamics of an $N$ particles system evolving
according the gradient flow of an energy functional. The particle system is a
consistent approximation of the Lagrangian formulation of a one parameter
family of non-local drift-diffusion equations in one spatial dimension. We
shall prove the global in time existence of the trajectories of the particles
(under a sufficient condition on the initial distribution) and give two blow-up
criteria. All these results are consequences of the competition between the
discrete entropy and the discrete interaction energy. They are also consistent
with the continuous setting, that in turn is a one dimension reformulation of
the parabolic-elliptic Keller-Segel in high dimensions.


title:
Combinatorial approaches to Hopf bifurcations in systems of interacting
  elements

abstract:
  We describe combinatorial approaches to the question of whether families of
real matrices admit pairs of nonreal eigenvalues passing through the imaginary
axis. When the matrices arise as Jacobian matrices in the study of dynamical
systems, these conditions provide necessary conditions for Hopf bifurcations to
occur in parameterised families of such systems. The techniques depend on the
spectral properties of additive compound matrices: in particular, we associate
with a product of matrices a signed, labelled digraph termed a DSR^[2] graph,
which encodes information about the second additive compound of this product. A
condition on the cycle structure of this digraph is shown to rule out the
possibility of nonreal eigenvalues with positive real part. The techniques
developed are applied to systems of interacting elements termed "interaction
networks", of which networks of chemical reactions are a special case.


title: Slicing the Sierpi\'nski gasket

abstract:
  We investigate the dimension of intersections of the Sierpi\'nski gasket with
lines. Our first main result describes a countable, dense set of angles that
are exceptional for Marstrand's theorem. We then provide a multifractal
analysis for the set of points in the projection for which the associated slice
has a prescribed dimension.


title: Markets Evolution After the Credit Crunch

abstract:
  We review the main changes in the interbank market after the financial crisis
started in August 2007. In particular, we focus on the fixed income market and
we analyse the most relevant empirical evidences regarding the divergence of
the existing basis between interbank rates with different tenor, such as Libor
and OIS. We also discuss a qualitative explanation of these effects based on
the consideration of credit and liquidity variables. Then, we focus our
attention on the diffusion of collateral agreements among OTC derivatives
market counterparties, and on the consequent change of paradigm for pricing
derivatives. We illustrate the main qualitative features of the new market
practice, called CSA discounting, and we point out the most relevant issues for
market players associated to its adoption.


title:
Antiprotons from Dark Matter: Current constraints and future
  sensitivities

abstract:
  We systematically analyze the impact of current and foreseen cosmic ray
antiproton measurements on the properties of Dark Matter (DM). We find that: 1)
The current data from PAMELA impose constraints on annihilating and decaying DM
which are similar to (or even slightly stronger than) the most stringent bounds
coming from Fermi gamma rays, for hadronic channels and with fiducial choices
for the astrophysical parameters. 2) The upcoming data from AMS-02 have the
power to improve these constraints by slightly less than one order of magnitude
and even to probe the thermal relic DM in the range 30-200 GeV, for hadronic
channels. However, with wider choices for the astrophysical parameters the
uncertainty on the constraints spans between one and two orders of magnitude.
We then explore the capabilities of early AMS-02, data to reconstruct the
underlying DM properties in the case of a positive detection of a significant
excess (attributed to DM annihilations) over the background. For hadronic
channels, we find that AMS-02 should be able to somewhat determine the DM mass
and the cross-section, but not the specific annihilation channel nor the
branching ratios. If other more exotic annihilation channels are allowed, the
reconstruction will be more challenging.


title: Ideal Whitehead Graphs in Out(F_r) III: Achieved Graphs in Rank 3

abstract:
  By proving precisely which singularity index lists arise from the pair of
invariant foliations for a pseudo-Anosov surface homeomorphism, Masur and
Smillie determined a Teichm\"uller flow invariant stratification of the space
of quadratic differentials. In this final paper of a three-paper series, we
give a first step to an $Out(F_r)$ analog of the Masur-Smillie theorem. Since
the ideal Whitehead graphs defined by Handel and Mosher give a strictly finer
invariant in the analogous $Out(F_r)$ setting, we determine which of the
twenty-one connected, simplicial, five-vertex graphs are ideal Whitehead graphs
of fully irreducible outer automorphisms in $Out(F_3)$.


title: Mass loading and knot formation in AGN jets by stellar winds

abstract:
  Jets from active galaxies propagate from the central black hole out to the
radio lobes on scales of hundreds of kiloparsecs. The jets may encounter giant
stars with strong stellar winds and produce observable signatures. For strong
winds and weak jets, the interaction may truncate the jet flow during its
transit via the mass loading. For weaker jets, the interaction can produce
knots in the jet. We present recent 3DMHD numerical simulations to model the
evolution of this jet-wind interaction and its observational consequences. We
explore (i) the relative mechanical luminosity of the radio jets and the
stellar winds (ii) the impact parameter between the jets' axis and the stellar
orbital path (iii) the relative magnetic field strength of the jets and the
stellar winds.


title:
Spectral curves in gauge/string dualities: integrability, singular
  sectors and regularization

abstract:
  We study the moduli space of the spectral curves $y^2=W'(z)^2+f(z)$ which
characterize the vacua of $\mathcal{N}=1$ U(n) supersymmetric gauge theories
with an adjoint Higgs field and a polynomial tree level potential $W(z)$. It is
shown that there is a direct way to associate a spectral density and a
prepotential functional to these spectral curves. The integrable structure of
the Whitham equations is used to determine the spectral curves from their
moduli. An alternative characterization of the spectral curves in terms of
critical points of a family of polynomial solutions $\mathbb{W}$ to
Euler-Poisson-Darboux equations is provided. The equations for these critical
points are a generalization of the planar limit equations for one-cut random
matrix models. Moreover, singular spectral curves with higher order branch
points turn out to be described by degenerate critical points of $\mathbb{W}$.
As a consequence we propose a multiple scaling limit method of regularization
and show that, in the simplest cases, it leads to the Painlev\`{e}-I equation
and its multi-component generalizations.


title: Black Holes in Six-dimensional Conformal Gravity

abstract:
  We study conformally-invariant theories of gravity in six dimensions. In four
dimensions, there is a unique such theory that is polynomial in the curvature
and its derivatives, namely Weyl-squared, and furthermore all solutions of
Einstein gravity are also solutions of the conformal theory. By contrast, in
six dimensions there are three independent conformally-invariant polynomial
terms one could consider. There is a unique linear combination (up to overall
scale) for which Einstein metrics are also solutions, and this specific theory
forms the focus of our attention in this paper. We reduce the equations of
motion for the most general spherically-symmetric black hole to a single
5th-order differential equation. We obtain the general solution in the form of
an infinite series, characterised by 5 independent parameters, and we show how
a finite 3-parameter truncation reduces to the already known Schwarzschild-AdS
metric and its conformal scaling. We derive general results for the
thermodynamics and the first law for the full 5-parameter solutions. We also
investigate solutions in extended theories coupled to conformally-invariant
matter, and in addition we derive some general results for conserved charges in
cubic-curvature theories in arbitrary dimensions.


title:
Exclusive $J/\psi$ and $\psi(2S)$ production in $pp$ collisions at
  $\sqrt{s}=7$ TeV

abstract:
  Exclusive $J/\psi$ and $\psi(2S)$ vector meson production has been observed
in the dimuon channel using the LHCb detector. The cross-section times
branching fractions to two muons with pseudorapidities between 2.0 and 4.5 are
measured to be $ \sigma_{pp\rightarrow J/\psi (\rightarrow \mu^{+} \mu^{-})}
(2.0 <\eta_{\mu^{\pm}}< 4.5) = 307 \pm 21 \pm 36 \text{pb},
\sigma_{pp\rightarrow \psi(2S) (\rightarrow \mu^{+} \mu^{-})} (2.0
<\eta_{\mu^{\pm}}< 4.5) = 7.8 \pm 1.3 \pm 1.0 \text{pb}, $ where the first
uncertainties are statistical and the second are systematic. The measurements
are found to be in good agreement with results from previous experiments and
theoretical predictions. The $J/\psi$ photoproduction cross-section has been
measured as a function of the photon-proton centre-of-mass energy. The results
are consistent with measurements obtained at HERA and confirm a similar power
law behaviour for the photoproduction cross-section.


title: Newton's Method and Symmetry for Semilinear Elliptic PDE on the Cube

abstract:
  We seek discrete approximations to solutions $u:\Omega \to R$ of semilinear
elliptic partial differential equations of the form $\Delta u + f_s(u) = 0$,
where $f_s$ is a one-parameter family of nonlinear functions and $\Omega$ is a
domain in $R^d$. The main achievement of this paper is the approximation of
solutions to the PDE on the cube $\Omega=(0,\pi)^3 \subseteq R^3$. There are
323 possible isotropy subgroups of functions on the cube, which fall into 99
conjugacy classes. The bifurcations with symmetry in this problem are quite
interesting, including many with 3-dimensional critical eigenspaces. Our
automated symmetry analysis is necessary with so many isotropy subgroups and
bifurcations among them, and it allows our code to follow one branch in each
equivalence class that is created at a bifurcation point. Our most complicated
result is the complete analysis of a degenerate bifurcation with a
6-dimensional critical eigenspace.
  This article extends the authors' work in {\it Automated Bifurcation Analysis
for Nonlinear Elliptic Partial Difference Equations on Graphs} (Int. J. of
Bifurcation and Chaos, 2009), wherein they combined symmetry analysis with
modified implementations of the gradient Newton-Galerkin algorithm (GNGA,
Neuberger and Swift) to automatically generate bifurcation diagrams and
solution graphics for small, discrete problems with large symmetry groups. The
code described in the current paper is efficiently implemented in parallel,
allowing us to investigate a relatively fine-mesh discretization of the cube.
We use the methodology and corresponding library presented in our paper {\it An
MPI Implementation of a Self-Submitting Parallel Job Queue} (Int. J. of
Parallel Prog., 2012).


title:
Finding the Higgs boson in decays to Z gamma using the matrix element
  method at Next-to-Leading Order

abstract:
  We illustrate how the Matrix Element Method at Next-to-Leading Order
(MEM@NLO) can be used to discriminate between events arising from the
production of a Higgs boson, which subsequently decays to a final state
consisting of ell^+ell^-gamma, and the background production of the same final
state. We illustrate how the method could be used in an experimental analysis
by devising cuts on the signal (P_S) and background (P_B) weights that are
computed event-by-event in this approach. We find that we can increase the
S/sqrt(B) ratio by around 50\% compared to an invariant mass fit on its own.
Considering only statistical uncertainty, this is equivalent to recording a
factor of around two times more integrated luminosity.


title: Radio to gamma-ray variability study of blazar S5 0716+714

abstract:
  We present the results of a series of radio, optical, X-ray and gamma-ray
observations of the BL Lac object S50716+714 carried out between April 2007 and
January 2011. The multi-frequency observations were obtained using several
ground and space based facilities. The intense optical monitoring of the source
reveals faster repetitive variations superimposed on a long-term variability
trend at a time scale of ~350 days. Episodes of fast variability recur on time
scales of ~ 60-70 days. The intense and simultaneous activity at optical and
gamma-ray frequencies favors the SSC mechanism for the production of the
high-energy emission. Two major low-peaking radio flares were observed during
this high optical/gamma-ray activity period. The radio flares are characterized
by a rising and a decaying stage and are in agreement with the formation of a
shock and its evolution. We found that the evolution of the radio flares
requires a geometrical variation in addition to intrinsic variations of the
source. Different estimates yield a robust and self-consistent lower limits of
\delta > 20 and equipartition magnetic field B_eq > 0.36 G. Causality arguments
constrain the size of emission region \theta < 0.004 mas. We found a
significant correlation between flux variations at radio frequencies with those
at optical and gamma-rays. The optical/GeV flux variations lead the radio
variability by ~65 days. The longer time delays between low-peaking radio
outbursts and optical flares imply that optical flares are the precursors of
radio ones. An orphan X-ray flare challenges the simple, one-zone emission
models, rendering them too simple. Here we also describe the spectral energy
distribution modeling of the source from simultaneous data taken through
different activity periods.


title: CPT analysis with top physics

abstract:
  We discuss the possibility of observing CPT violation from top anti-top
production in hadronic colliders. We study a general approach by analyzing
constraints on the mass difference between the top and anti-top quarks. We
present current bounds from Tevatron data, and comment on the prospects for
improving these bounds at the LHC and the ILC.


title:
Construction of the Conserved Non-linear Zeta via the Effective Action
  for Perfect Fluids

abstract:
  We consider the problem of how to construct the curvature perturbation
$\zeta$ to nonlinear levels, which is expected to evolve time independently on
super-horizon scales; in particular we concentrate on the situation where the
universe is dominated by a perfect fluid. We have used a low energy/long
wavelength effective action to model the fluid sector. Different from previous
work, our approach assumes neither the absence of vector and tensor
perturbations nor ``local homogeneity and isotropy''. As a corollary, we also
show that the nonlinearly defined graviton field $\gamma_{ij}$ is conserved
outside the horizon in the same manner as $\zeta$ is.


title:
Graphs with maximum degree D at least 17 and maximum average degree less
  than 3 are list 2-distance (D+2)-colorable

abstract:
  For graphs of bounded maximum average degree, we consider the problem of
2-distance coloring. This is the problem of coloring the vertices while
ensuring that two vertices that are adjacent or have a common neighbor receive
different colors. It is already known that planar graphs of girth at least 6
and of maximum degree D are list 2-distance (D+2)-colorable when D>=24 (Borodin
and Ivanova (2009)) and 2-distance (D+2)-colorable when D>=18 (Borodin and
Ivanova (2009)). We prove here that D>=17 suffices in both cases. More
generally, we show that graphs with maximum average degree less than 3 and
D>=17 are list 2-distance (D+2)-colorable. The proof can be transposed to list
injective (D+1)-coloring.


title: Limb-Darkening Coefficients for Eclipsing White Dwarfs

abstract:
  We present extensive calculations of linear and non-linear limb-darkening
coefficients as well as complete intensity profiles appropriate for modeling
the light-curves of eclipsing white dwarfs. We compute limb-darkening
coefficients in the Johnson-Kron-Cousins UBVRI photometric system as well as
the Large Synoptic Survey Telescope (LSST) ugrizy system using the most
up-to-date model atmospheres available. In all, we provide the coefficients for
seven different limb-darkening laws. We describe the variations of these
coefficients as a function of the atmospheric parameters, including the effects
of convection at low effective temperatures. Finally, we discuss the importance
of having readily available limb-darkening coefficients in the context of
present and future photometric surveys like the LSST, Palomar Transient
Factory, and the Panoramic Survey Telescope and Rapid Response System
(Pan-STARRS). The LSST, for example, may find ~10^5 eclipsing white dwarfs. The
limb-darkening calculations presented here will be an essential part of the
detailed analysis of all of these systems.


abstract:
  This paper summarizes the three-day international workshop "Radio Stars and
Their Lives in the Galaxy", held at the Massachusetts Institute of Technology
Haystack Observatory on 2012 October 3-5. The workshop was organized to provide
a forum for the presentation and discussion of advances in stellar and solar
astrophysics recently (or soon to be) enabled by the latest generation of
state-of-the-art observational facilities operating from meter to submillimeter
wavelengths. The meeting brought together both observers and theorists to
discuss how radio wavelength observations are providing new and unique insights
into the workings of stars and their role in the Galactic ecosystem. Topics
covered included radio emission from hot and cool stars (from the pre- to
post-main-sequence), the Sun as a radio star, circumstellar chemistry,
planetary nebulae, white dwarf binaries and novae, supernova progenitors, and
radio stars as probes of the Galaxy.


title:
Coherence and Indistinguishability of Single Electrons Emitted by
  Independent Sources

abstract:
  The on-demand emission of coherent and indistinguishable electrons by
independent synchronized sources is a challenging task of quantum electronics,
in particular regarding its application for quantum information processing.
Using two independent on-demand electron sources, we trigger the emission of
two single-electron wavepackets at different inputs of an electronic
beamsplitter. Whereas classical particles would be randomly partitioned by the
splitter, we observe two-particle interferences resulting from quantum
exchange. Both electrons, emitted in indistinguishable wavepackets with
synchronized arrival time on the splitter, exit in different outputs as
recorded by the low frequency current noise. The demonstration of two-electron
interference provides the possibility to manipulate coherent and
indistinguishable single-electron wavepackets in quantum conductors.


title: Factors of Pisot tiling spaces and the coincidence rank conjecture

abstract:
  We consider the structure of Pisot substitution tiling spaces, in particular,
the structure of those spaces for which the translation action does not have
pure discrete spectrum. Such a space is always a measurable m-to-one cover of
an action by translation on a group called the maximal equicontinuous factor.
The integer m is the coincidence rank of the substitution and equals one if and
only if translation on the tiling space has pure discrete spectrum. By
considering factors intermediate between a tiling space and its maximal
equicontinuous factor, we establish a lower bound on the cohomology of a
one-dimensional Pisot substitution tillng space with coincidence rank two and
dilation of odd norm. The Coincidence Rank Conjecture, for coincidence rank
two, is a corollary.


title: Modeling the Panchromatic Spectral Energy Distributions of Galaxies

abstract:
  The spectral energy distributions (SEDs) of galaxies are shaped by nearly
every physical property of the system, including the star formation history,
metal content, abundance pattern, dust mass, grain size distribution, star-dust
geometry, and interstellar radiation field. The principal goal of stellar
population synthesis (SPS) is to extract these variables from observed SEDs. In
this review I provide an overview of the SPS technique and discuss what can be
reliably measured from galaxy SEDs. Topics include stellar masses, star
formation rates and histories, metallicities and abundance patterns, dust
properties, and the stellar initial mass function.


title:
The unifying theory of scaling in thermal convection: The updated
  prefactors

abstract:
  The unifying theory of scaling in thermal convection (Grossmann & Lohse
(2000)) (henceforth the GL theory) suggests that there are no pure power laws
for the Nusselt and Reynolds numbers as function of the Rayleigh and Prandtl
numbers in the experimentally accessible parameter regime. In Grossmann & Lohse
(2001) the dimensionless parameters of the theory were fitted to 155
experimental data points by Ahlers & Xu (2001) in the regime $3\times 10^7 \le
Ra \le 3 \times 10^{9}$ and $4\le Pr \le 34$ and Grossmann & Lohse (2002) used
the experimental data point from Qiu & Tong (2001) and the fact that Nu(Ra,Pr)
is independent of the parameter a, which relates the dimensionless kinetic
boundary thickness with the square root of the wind Reynolds number, to fix the
Reynolds number dependence. Meanwhile the theory is on one hand well confirmed
through various new experiments and numerical simulations. On the other hand
these new data points provide the basis for an updated fit in a much larger
parameter space. Here we pick four well established (and sufficiently distant)
Nu(Ra,Pr) data points and show that the resulting Nu(Ra,Pr) function is in
agreement with almost all established experimental and numerical data up to the
ultimate regime of thermal convection, whose onset also follows from the
theory. One extra Re(Ra,Pr) data point is used to fix Re(Ra,Pr). As Re can
depend on the definition and the aspect ratio the transformation properties of
the GL equations are discussed in order to show how the GL coefficients can
easily be adapted to new Reynolds number data while keeping Nu(Ra,Pr)
unchanged.


title: Relations for Bernoulli--Barnes Numbers and Barnes Zeta Functions

abstract:
  The \emph{Barnes $\zeta$-function} is \[
  \zeta_n (z, x; \a) := \sum_{\m \in \Z_{\ge 0}^n} \frac{1}{\left(x + m_1 a_1 +
\dots + m_n a_n \right)^z} \] defined for $\Re(x) > 0$ and $\Re(z) > n$ and
continued meromorphically to $\C$. Specialized at negative integers $-k$, the
Barnes $\zeta$-function gives \[
  \zeta_n (-k, x; \a) = \frac{(-1)^n k!}{(k+n)!} \, B_{k+n} (x; \a) \] where
$B_k(x; \a)$ is a \emph{Bernoulli--Barnes polynomial}, which can be also
defined through a generating function that has a slightly more general form
than that for Bernoulli polynomials. Specializing $B_k(0; \a)$ gives the
\emph{Bernoulli--Barnes numbers}. We exhibit relations among Barnes
$\zeta$-functions, Bernoulli--Barnes numbers and polynomials, which generalize
various identities of Agoh, Apostol, Dilcher, and Euler.


title:
Generalized fountain theorem and application to strongly indefinite
  semilinear problems

abstract:
  By using the degree theory and the $\tau-$topology of Kryszewski and Szulkin,
we establish a version of the Fountain Theorem for strongly indefinite
functionals. The abstract result will be applied for studying the existence of
infinitely many solutions of two strongly indefinite semilinear problems
including the semilinear Schr\"{o}dinger equation.


title:
Opening the 21cm EoR Window: Measurements of Foreground Isolation with
  PAPER

abstract:
  We present new observations with the Precision Array for Probing the Epoch of
Reionization (PAPER) with the aim of measuring the properties of foreground
emission for 21cm Epoch of Reionization experiments at 150 MHz. We focus on the
footprint of the foregrounds in cosmological Fourier space to understand which
modes of the 21cm power spectrum will most likely be compromised by foreground
emission. These observations confirm predictions that foregrounds can be
isolated to a "wedge"-like region of 2D (k-perpendicular, k-parallel)-space,
creating a window for cosmological studies at higher k-parallel values. We also
find that the emission extends past the nominal edge of this wedge due to
spectral structure in the foregrounds, with this feature most prominent on the
shortest baselines. Finally, we filter the data to retain only this "unsmooth"
emission and image specific k-parallel modes of it. The resultant images show
an excess of power at the lowest modes, but no emission can be clearly
localized to any one region of the sky. This image is highly suggestive that
the most problematic foregrounds for 21cm EoR studies will not be easily
identifiable bright sources, but rather an aggregate of fainter emission.


title:
Scalable universal holonomic quantum computation realized with an
  adiabatic quantum data bus and potential implementation using superconducting
  flux qubits

abstract:
  In this paper we examine the use of an adiabatic quantum data transfer
protocol to build a universal quantum computer. Single qubit gates are realized
by using a bus protocol to transfer qubits of information down a spin chain
with a unitary twist. This twist arises from altered couplings on the chain
corresponding to unitary rotations performed on one region of the chain. We
show how a controlled NOT gate can be realized by using a control qubit with
Ising type coupling. The method discussed here can be extended to non-adiabatic
quantum bus protocols. We also examine the potential of realizing such a
quantum computer by using superconducting flux qubits.


title: Towards Optimal Broadcast in Wireless Networks

abstract:
  Broadcast is a fundamental operation in networks, especially in wireless
Mobile Ad Hoc NETworks (MANET). For example, some form of broadcasting is used
by all on-demand MANET routing protocols, when there is uncertainty as to the
location of the destination node, or for service discovery. Being such a basic
operation of the networking protocols, the importance of efficient broadcasting
has long been recognized by the networking community. Numerous papers proposed
increasingly more efficient implementation of broadcasting, while other studies
presented bounds on broadcast performance. In this work, we present a new
approach to efficient broadcast in networks with dynamic topologies, such as
MANET, and we introduce a new broadcasting algorithm for such networking
environments. We evaluate our algorithm, showing that its performance comes
remarkably close to the corresponding theoretical performance bounds, even in
the presence of packet loss due to, for example, MAC-layer collisions.
Furthermore, we compare the performance of the proposed algorithm with other
recently proposed schemes, including in various mobility settings.


title:
What is half a neutrino? Reviewing cosmological constraints on neutrinos
  and dark radiation

abstract:
  Neutrinos are one of the major puzzles in modern physics. Despite
measurements of mass differences, the Standard Model of particle physics
describes them as exactly massless. Additionally, recent measurements from both
particle physics experiments and cosmology indicate the existence of more than
the three Standard Model species. Here we review the cosmological evidence and
its possible interpretations.


title: Lifting $N$-dimensional Galois representations to characteristic zero

abstract:
  Let $F$ be a number field, let $N\geq 3$ be an integer, and let $k$ be a
finite field of characteristic $\ell$. We show that if $\rb:G_F\longrightarrow
GL_N(k)$ is a continuous representation with image of $\rb$ containing
$SL_N(k)$ then, under moderate conditions at primes dividing $\ell\infty$,
there is a continuous representation $\rho:G_F\longrightarrow GL_N(W(k))$
unramified outside finitely many primes with $\rb\sim\rho\mod{\ell}$.


title: The detection of C60 in the well-characterized planetary nebula M1-11

abstract:
  We performed multiwavelength observations of the young planetary nebula (PN)
M1-11 and obtained its elemental abundances, dust mass, and the evolutionary
status of the central star. The AKARI/IRC, VLT/VISIR, and Spitzer/IRS spectra
show features due to carbon-rich dust, such as the 3.3, 8.6, and 11.3 um
features due to polycyclic aromatic hydrocarbons (PAHs), a smooth continuum
attributable to amorphous carbon, and the broad 11.5 and 30 um features often
ascribed to SiC and MgS, respectively. We also report the presence of an
unidentified broad feature at 16-22 um, similar to the feature found in
Magellanic Cloud PNe with either C-rich or O-rich gas-phase compositions. We
identify for the first time in M1-11 spectral lines at 8.5 (blended with PAH),
17.3, and 18.9 um that we attribute to the C60 fullerene. This identification
is strengthened by the fact that other Galactic PNe in which fullerenes are
detected, have similar central stars, similar gas-phase abundances, and a
similar dust composition to M1-11. The weak radiation field due to the
relatively cool central stars in these PNe may provide favorable conditions for
fullerenes to survive in the circumstellar medium. Using the photo-ionization
code CLOUDY, combined with a modified blackbody, we have fitted the ~0.1-90 um
spectral energy distribution and determined the dust mass in the nebula to be
~3.5x10^{-4} Msun$. Our chemical abundance analysis and SED model suggest that
M1-11 is perhaps a C-rich PN with C/O ratio in the gas-phase of +0.19 dex, and
that it evolved from a 1-1.5 Msun star.