title:
Explanation of the Muon g-2 Anomaly with Vectorlike Leptons and its
  Implications for Higgs Decays

abstract:
  The deviation of the measured value of the muon anomalous magnetic moment
from the standard model prediction can be completely explained by mixing of the
muon with extra vectorlike leptons, L and E, near the electroweak scale. This
mixing simultaneously contributes to the muon mass. We show that the
correlation between contributions to the muon mass and muon g-2 is controlled
by the mass of the neutrino originating from the doublet L. Positive
correlation, simultaneously explaining both measured values, requires this mass
below 200 GeV. The decay rate of the Higgs boson to muon pairs is modified and,
in the region of the parameter space that can explain the muon anomalous
magnetic moment within one standard deviation, it ranges from 0.5 to 24 times
the standard model prediction. In the same scenario, $h \to \gamma \gamma$ can
be enhanced or lowered by ~50% from the standard model prediction. The
explanation of the muon g-2 anomaly and predictions for $h \to \gamma \gamma$
are not correlated since these are controlled by independent parameters. This
scenario can be embedded in a model with three complete vectorlike families
featuring gauge coupling unification, sufficiently stable proton, and the Higgs
quartic coupling remaining positive all the way to the grand unification scale.


title: Disentangling sources of anomalous diffusion

abstract:
  We show that some important properties of subbdiffusion of unknown origin
(including those of mixed origin) can be easily assessed when findeng the
"fundamental moment" of the corresponding process, i.e., the one which is
additive in time. In subordinated processes, the index of the fundamental
moment is inherited from the parent process and its time-dependence from the
leading one. In models of particle's motion in disordered potentials, the index
is governed by the structural part of the disorder while the time dependence is
given by its energetic part.

categories: physics.data-an math-ph math.MP physics.bio-ph


title: An exploration of hadronic interactions in blazars using IceCube

abstract:
  Context: Hadronic models, involving matter (proton or nuclei) acceleration in
blazar jets, imply high energy photon and neutrino emissions due to
interactions of high-energy protons with matter and/or radiation in the source
environment. Aims: This paper shows that the sensitivity of the IceCube
neutrino telescope in its 40-string configuration (IC-40) is already at the
level of constraining the parameter space of purely hadronic scenarios of
activity of blazars. Methods: Assuming that the entire source power originates
from hadronic interactions, and assuming that the models describe the data, we
estimate the expected neutrino flux from blazars based on the observed
gamma-ray flux by Fermi, simultaneously with IC-40 observations. We consider
two cases separately to keep the number of constrainable parameters at an
acceptable level: proton-proton or proton-gamma interactions are dominant.
Comparing the IC-40 sensitivity to the neutrino flux expected from some of the
brightest blazars, we constrain model parameters characterizing the parent
high-energy proton spectrum. Results: We find that when pp interactions
dominate, some constraints on the primary proton spectrum can be imposed. For
instance, for the tightest constrained source 3C 454.3, the very high energy
part of the spectra of blazars is constrained to be harder than E^-2 with
cut-off energies in the range of Ecut >10^18 eV. When interactions of
high-energy protons on soft photon fields dominate, we can find similarly tight
constraints on the proton spectrum parameters. [abridged]


title:
Emergent Schwarzschild and Reissner-Nordstrom black holes in 4D: An
  effective curvature sourced by a B2-field on a D4-brane

abstract:
  We obtain a Schwarzschild and a Reissner-Nordstrom emergent black holes, by
exploring the torsion dynamics in a generalized curvature formulation,
underlying an effective D4-brane on S1. It is shown that a constant effective
metric, sourced by a background fluctuation in B2-potential, on a D3-brane
receives a dynamical quantum correction in presence of an electric charge.


title: Graphs with $\chi=\Delta$ have big cliques

abstract:
  Brooks' Theorem states that if a graph has $\Delta\ge 3$ and $\omega \le
\Delta$, then $\chi \le \Delta$. Borodin and Kostochka conjectured that if
$\Delta\ge 9$ and $\omega\le \Delta-1$, then $\chi\le \Delta-1$. We show that
if $\Delta\ge 13$ and $\omega \le \Delta-4$, then $\chi\le \Delta-1$. For a
graph $G$, let $\mathcal{H}$ denote the subgraph of $G$ induced by vertices of
degree $\Delta$. We also show that if $\omega\le \Delta-1$ and
$\omega(\mathcal{H})\le \Delta-6$, then $\chi\le \Delta-1$.


title: Millimeter Recombination Lines from LkHalpha 101

abstract:
  We present new millimeter observations of the ionized wind from the massive
young stellar object LkHalpha101, made with the IRAM interferometer and 30m
telescope. Several recombination lines, including higher order transitions,
were detected for the first time at radio wavelengths in this source. From
three alpha-transitions we derive an accurate value for the stellar velocity
and, for the first time, an unambiguous expansion velocity of the wind which is
55 km/s, much slower than reported previously, and the mass loss rate is 1.8e-6
solar masses per year. The wide band continuum spectra and the interferometer
visibilities show that the density of the wind falls off more steeply than
compatible with constant-velocity expansion. We argue that these properties
indicate that the wind is launched from a radially narrow region of the
circumstellar disk, and we propose that slow speed and a steep density gradient
are characteristic properties of the evolutionary phase where young stars of
intermediate and high mass clear away the gaseous component of their accretion
disks.
  The recombination lines are emitted close to local thermal equilibrium, but
the higher order transitions appear systematically broader and weaker than
expected, probably due to impact broadening. Finally, we show that LkHalpha101
shares many properties with MWC349, the only other stellar wind source where
radio recombination lines have been detected, some of them masing. We argue
that LkHalpha101 evades masing at millimeter wavelengths because of the disk's
smaller size and unfavorable orientation. Some amplification may however be
detectable at shorter wavelengths.


title:
Space-time goal-oriented reduced basis approximation for linear wave
  equation

abstract:
  In this paper, we study numerically the linear damped second-order hyperbolic
partial differential equation (PDE) with affine parameter dependence using a
goal-oriented approach by finite element (FE) and reduced basis (RB) methods.
The main contribution of this paper is the "goal-oriented" proper orthogonal
decomposition (POD)-Greedy sampling procedure within the RB approximation
context. First, we introduce the RB recipe: Galerkin projection onto a space
$Y_N$ spanned by solutions of the governing PDE at $N$ selected points in
parameter space. This set of $N$ parameter points is constructed by the
standard POD-Greedy sampling procedure already developed. Second, based on the
affine parameter dependence, we make use of the offline-online computational
procedures: in the offline stage, we generate the RB space; in the online
stage, given a new parameter value, we calculate rapidly and accurately the
space-time RB output of interest and its associated asymptotic error. The
proposed goal-oriented POD-Greedy sampling procedure can now be implemented and
will look for the parameter points such that it minimizes this (asymptotic)
output error rather than the solution error (or, error indicator which is the
dual norm of residual) as in the standard POD-Greedy procedure. Numerical
results show that the new goal-oriented POD-Greedy sampling procedure improves
significantly the accuracy of the space-time output computation in comparison
with the standard POD-Greedy one. The method is thus ideally suited for
repeated, rapid and reliable evaluation of input-output relationships within
the space-time setting.


title: On the asymptotic evolution of finite energy Airy wavefunctions

abstract:
  In general, there is an inverse relation between the degree of localization
of a wavefunction of a certain class and its transform representation dictated
by the scaling property of the Fourier transform. We report that in the case of
finite energy Airy wavepackets a simultaneous increase in their localization in
the direct and transform domains can be obtained as the apodization parameter
is varied. One consequence of this is that the far field diffraction rate of a
finite energy Airy beam decreases as the beam localization at the launch plane
increases. We analyse the asymptotic properties of finite energy Airy
wavefunctions using the stationary phase method. We obtain one dominant
contribution to the long term evolution that admits a Gaussian-like
approximation, which displays the expected reduction of its broadening rate as
the input localization is increased.


title: Admissibility in Finitely Generated Quasivarieties

abstract:
  Checking the admissibility of quasiequations in a finitely generated (i.e.,
generated by a finite set of finite algebras) quasivariety Q amounts to
checking validity in a suitable finite free algebra of the quasivariety, and is
therefore decidable. However, since free algebras may be large even for small
sets of small algebras and very few generators, this naive method for checking
admissibility in $\Q$ is not computationally feasible. In this paper,
algorithms are introduced that generate a minimal (with respect to a multiset
well-ordering on their cardinalities) finite set of algebras such that the
validity of a quasiequation in this set corresponds to admissibility of the
quasiequation in Q. In particular, structural completeness (validity and
admissibility coincide) and almost structural completeness (validity and
admissibility coincide for quasiequations with unifiable premises) can be
checked. The algorithms are illustrated with a selection of well-known finitely
generated quasivarieties, and adapted to handle also admissibility of rules in
finite-valued logics.


title: Black hole solutions in d=5 Chern-Simons gravity

abstract:
  The five dimensional Einstein-Gauss-Bonnet gravity with a negative
cosmological constant becomes, for a special value of the Gauss-Bonnet coupling
constant, a Chern-Simons (CS) theory of gravity. In this work we discuss the
properties of several different types of black object solutions of this model.
Special attention is paid to the case of spinning black holes with
equal-magnitude angular momenta which posses a regular horizon of spherical
topology. Closed form solutions are obtained in the small angular momentum
limit. Nonperturbative solutions are constructed by solving numerically the
equations of the model. Apart from that, new exact solutions describing static
squashed black holes and black strings are also discussed. The action and
global charges of all configurations studied in this work are obtained by using
the quasilocal formalism with boundary counterterms generalized for the case of
a d=5 CS theory.


title: Temporal networks of face-to-face human interactions

abstract:
  The ever increasing adoption of mobile technologies and ubiquitous services
allows to sense human behavior at unprecedented levels of details and scale.
Wearable sensors are opening up a new window on human mobility and proximity at
the finest resolution of face-to-face proximity. As a consequence, empirical
data describing social and behavioral networks are acquiring a longitudinal
dimension that brings forth new challenges for analysis and modeling. Here we
review recent work on the representation and analysis of temporal networks of
face-to-face human proximity, based on large-scale datasets collected in the
context of the SocioPatterns collaboration. We show that the raw behavioral
data can be studied at various levels of coarse-graining, which turn out to be
complementary to one another, with each level exposing different features of
the underlying system. We briefly review a generative model of temporal contact
networks that reproduces some statistical observables. Then, we shift our focus
from surface statistical features to dynamical processes on empirical temporal
networks. We discuss how simple dynamical processes can be used as probes to
expose important features of the interaction patterns, such as burstiness and
causal constraints. We show that simulating dynamical processes on empirical
temporal networks can unveil differences between datasets that would otherwise
look statistically similar. Moreover, we argue that, due to the temporal
heterogeneity of human dynamics, in order to investigate the temporal
properties of spreading processes it may be necessary to abandon the notion of
wall-clock time in favour of an intrinsic notion of time for each individual
node, defined in terms of its activity level. We conclude highlighting several
open research questions raised by the nature of the data at hand.


title:
On energy exchange rate and entropy production operators in quantum
  fluctuation-dissipation relations

abstract:
  For quantum systems with externally time-varied Hamiltonians a definition of
operators of system's energy change rate (work per unit time) and entropy
production observables is suggested and discussed in the context of rigorous
statistical equalities (generalized fluctuation-dissipation relations) under
the Jordan-symmetrized chronological operator ordering rule.


title: The CRT is the scaling limit of random dissections

abstract:
  We study the graph structure of large random dissections of polygons sampled
according to Boltzmann weights, which encompasses the case of uniform
dissections or uniform $p$-angulations. As their number of vertices $n$ goes to
infinity, we show that these random graphs, rescaled by $n^{-1/2}$, converge in
the Gromov--Hausdorff sense towards a multiple of Aldous' Brownian tree when
the weights decrease sufficiently fast. The scaling constant depends on the
Boltzmann weights in a rather amusing and intriguing way, and is computed by
making use of a Markov chain which compares the length of geodesics in
dissections with the length of geodesics in their dual trees.


title: Hyperbolic systems and propagation on causal manifolds

abstract:
  This is essentially a survey paper in which we solve the global Cauchy
problem on causal manifolds for hyperbolic systems of linear partial
differential equations in the framework of hyperfunctions. Besides the
classical Cauchy-Kowalevsky theorem, our proofs only use tools from the
microlocal theory of sheaves, that is, tools of purely algebraic and geometric
nature.


title: Analysis of a non-work conserving Generalized Processor Sharing queue

abstract:
  We consider in this paper a non work-conserving Generalized Processor Sharing
(GPS) system composed of two queues with Poisson arrivals and exponential
service times. Using general results due to Fayolle \emph{et al}, we first
establish the stability condition for this system. We then determine the
functional equation satisfied by the generating function of the numbers of jobs
in both queues and the associated Riemann-Hilbert problem. We prove the
existence and the uniqueness of the solution. This allows us to completely
characterize the system, in particular to compute the empty queue probability.
We finally derive the tail asymptotics of the number of jobs in one queue.


title:
Cooperative Relaying in a Poisson Field of Interferers: A Diversity
  Order Analysis

abstract:
  This work analyzes the gains of cooperative relaying in interference-limited
networks, in which outages can be due to interference and fading. A stochastic
model based on point process theory is used to capture the spatial randomness
present in contemporary wireless networks. Using a modification of the
diversity order metric, the reliability gain of selection decode-and-forward is
studied for several cases. The main results are as follows: the achievable
\emph{spatial-contention} diversity order (SC-DO) is equal to one irrespective
of the type of channel which is due to the ineffectiveness of the relay in the
MAC-phase (transmit diversity). In the BC-phase (receive diversity), the SC-DO
depends on the amount of fading and spatial interference correlation. In the
absence of fading, there is a hard transition between SC-DO of either one or
two, depending on the system parameters.


title: Confinement as a tool to probe amorphous order

abstract:
  We study the effect of confinement on glassy liquids using Random First Order
Transition theory as framework. We show that the characteristic length-scale
above which confinement effects become negligible is related to the
point-to-set length-scale introduced to measure the spatial extent of amorphous
order in super-cooled liquids. By confining below this characteristic size, the
system becomes a glass. Eventually, for very small sizes, the effect of the
boundary is so strong that any collective glassy behavior is wiped out. We
clarify similarities and differences between the physical behaviors induced by
confinement and by pinning particles outside a spherical cavity (the protocol
introduced to measure the point-to-set length). Finally, we discuss possible
numerical and experimental tests of our predictions.


title: Boundary conditions for metric fluctuations in Lifshitz

abstract:
  We consider the quantisation of linearised fluctuations of the metric and
matter fields about a Lifshitz background, exploring the possibility of
alternative boundary conditions, allowing the slow fall-off modes to fluctuate.
We find that for $z >2$, slow fall-off modes for some of the linearised
fluctuations are normalizable, which opens up the possibility of considering
alternative boundary conditions. Analysing stability, we find that alternative
boundary conditions for the momentum density are allowed, but alternative
boundary conditions for the energy density lead to an instability of the type
we recently discovered in a similar analysis for scalar fields on a fixed
Lifshitz background. Our investigation is in the context of the simple massive
vector model, but we would expect the conclusions to be more general.


title:
Cold nuclear matter effect measured with high pT hadrons and jets in
  200GeV d+Au collisions in PHENIX

abstract:
  High pT \pi^0 and \eta, as well as jets are measured using high statistics
d+Au collision data collected in RHIC Year-2008 run. Both R_{dA} and R_{cp} for
three observables are found to be very consistent each other within quoted
systematic and statistical uncertainties. It was found that the R_{dA} is
strongly centrality dependent as opposed to the expectations from theoretical
models. An explanation of the centrality dependence from the experimental point
of view is presented.


title:
More on Superconductors via Gauge/Gravity Duality with Nonlinear Maxwell
  Field

abstract:
  We have developed the recent investigations on the second-order phase
transition in the holographic superconductor using the probe limit for a
nonlinear Maxwell field strength coupled to a massless scalar field. By
analytic methods, based on the variational Sturm- Liouville minimization
technique, we study the effects of the space-time dimension and the
non-linearity parameter on the critical temperature and the scalar condensation
of the dual operators on the boundary. Further, as a motivated result, we
analytically deduce the DC conductivity in the low and zero temperatures
regime. Especially in the zero temperature limit and in two dimensional toy
model, we thoroughly compute the conductivity analytically. Our work clarifies
more features of the holographic superconductors both in different space
dimensions and on the effect of the non-linearity in Maxwell's strength field.


title:
Topological entropy of quadratic polynomials and dimension of sections
  of the Mandelbrot set

abstract:
  Let c be a real parameter in the Mandelbrot set, and f_c(z):= z^2 + c. We
prove a formula relating the topological entropy of f_c to the Hausdorff
dimension of the set of rays landing on the real Julia set, and to the
Hausdorff dimension of the set of rays landing on the real section of the
Mandelbrot set, to the right of the given parameter c. We then generalize the
result by looking at the entropy of Hubbard trees: namely, we relate the
Hausdorff dimension of the set of external angles which land on a certain slice
of a principal vein in the Mandelbrot set to the topological entropy of the
quadratic polynomial f_c restricted to its Hubbard tree.


title: Giambelli and degeneracy locus formulas for classical G/P spaces

abstract:
  Let G be a classical complex Lie group, P any parabolic subgroup of G, and X
= G/P the corresponding homogeneous space, which parametrizes (isotropic)
partial flags of subspaces of a fixed vector space. In the mid 1990s, Fulton,
Pragacz, and Ratajski asked for global formulas which express the cohomology
classes of the universal Schubert varieties in flag bundles -- when the space X
varies in an algebraic family -- in terms of the Chern classes of the vector
bundles involved in their definition. This has applications to the theory of
degeneracy loci of vector bundles and is closely related to the Giambelli
problem for the torus-equivariant cohomology ring of X. In this article, we
explain the answer to these questions which was obtained in arXiv:0908.3628, in
terms of combinatorial data coming from the Weyl group.


title:
Does "model-free" forecasting really outperform the "true" model? A
  reply to Perretti et al

abstract:
  Estimating population models from uncertain observations is an important
problem in ecology. Perretti et al. observed that standard Bayesian state-space
solutions to this problem may provide biased parameter estimates when the
underlying dynamics are chaotic. Consequently, forecasts based on these
estimates showed poor predictive accuracy compared to simple "model-free"
methods, which lead Perretti et al. to conclude that "Model-free forecasting
outperforms the correct mechanistic model for simulated and experimental data".
However, a simple modification of the statistical methods also suffices to
remove the bias and reverse their results.


title: SUSY Searches for Inclusive Squark and Gluino Production at the LHC

abstract:
  A selection of recent searches for Supersymmetry conducted by the ATLAS and
CMS collaborations is presented, summarizing the relevant results for inclusive
squark and gluino production at the LHC. No indication for the existence of
Supersymmetry in terms of an excess above the Standard Model background is seen
by any analysis, therefore limits are reported on parameters of the various
models used to interpret the findings.


title:
An Approximate Version of the Jordan von Neumann Theorem for Finite
  Dimensional Real Normed Spaces

abstract:
  It is known that any normed vector space which satisfies the parallelogram
law is actually an inner product space. For finite dimensional normed vector
spaces over R, we formulate an approximate version of this theorem: if a space
approximately satisfies the parallelogram law, then it has a near isometry with
Euclidean space. In other words, a small von Neumann Jordan constant E + 1 for
X yields a small Banach-Mazur distance with R^n, d(X, R^n) < 1 + B_n E +
O(E^2). Finally, we examine how this estimate worsens as the dimension, n, of X
increases, with the conclusion that B_n grows quadratically with n.


title: Superconformal Indices and M2-Branes

abstract:
  We derive the superconformal index of the world-volume theory on M2-branes
probing the cone over an arbitrary Sasaki-Einstein seven-manifold. The index is
expressed in terms of the cohomology groups of the cone. We match our
supergravity results with known results from gauge theory. Along the way we
derive the spectrum of short Kaluza-Klein multiplets on generic Sasaki-Einstein
seven-manifolds.


title: Searching for intrinsic charm in the proton at the LHC

abstract:
  Despite rather long-term theoretical and experimental studies, the hypothesis
of the non-zero intrinsic (or valence-like) heavy quark component of the proton
distribution functions has not yet been confirmed or rejected. The LHC with
$pp$-collisions at $\sqrt{s}=$ 7--14 TeV will obviously supply extra unique
information concerning the above-mentioned component of the proton. To use the
LHC potential, first of all, one should select the parton-level (sub)processes
(and final-state signatures) that are most sensitive to the intrinsic heavy
quark contributions. To this end inclusive production of $c(b)$-jets
accompanied by photons is considered. On the basis of the performed theoretical
study it is demonstrated that the investigation of the intrinsic heavy quark
contributions looks very promising at the LHC in processes such as
$pp\rightarrow \gamma+ c(b)+X$.


title: Quaternionic K\"ahler metrics associated with special K\"ahler manifolds

abstract:
  We give an explicit formula for the quaternionic K\"ahler metrics obtained by
the HK/QK correspondence. As an application, we give a new proof of the fact
that the Ferrara-Sabharwal metric as well as its one-loop deformation is
quaternionic K\"ahler. A similar explicit formula is given for the analogous
(K/K) correspondence between K\"ahler manifolds endowed with a Hamiltonian
Killing vector field. As an example, we apply this formula in the case of an
arbitrary conical K\"ahler manifold.


title: LOFAR: The LOw-Frequency ARray

abstract:
  LOFAR, the LOw-Frequency ARray, is a new-generation radio interferometer
constructed in the north of the Netherlands and across europe. Utilizing a
novel phased-array design, LOFAR covers the largely unexplored low-frequency
range from 10-240 MHz and provides a number of unique observing capabilities.
Spreading out from a core located near the village of Exloo in the northeast of
the Netherlands, a total of 40 LOFAR stations are nearing completion. A further
five stations have been deployed throughout Germany, and one station has been
built in each of France, Sweden, and the UK. Digital beam-forming techniques
make the LOFAR system agile and allow for rapid repointing of the telescope as
well as the potential for multiple simultaneous observations. With its dense
core array and long interferometric baselines, LOFAR achieves unparalleled
sensitivity and angular resolution in the low-frequency radio regime. The LOFAR
facilities are jointly operated by the International LOFAR Telescope (ILT)
foundation, as an observatory open to the global astronomical community. LOFAR
is one of the first radio observatories to feature automated processing
pipelines to deliver fully calibrated science products to its user community.
LOFAR's new capabilities, techniques and modus operandi make it an important
pathfinder for the Square Kilometre Array (SKA). We give an overview of the
LOFAR instrument, its major hardware and software components, and the core
science objectives that have driven its design. In addition, we present a
selection of new results from the commissioning phase of this new radio
observatory.


title:
Iron impurities in gold and silver: Comparison of transport measurements
  to numerical renormalization group calculations exploiting non-Abelian
  symmetries

abstract:
  We consider iron impurities in the noble metals gold and silver and compare
experimental data for the resistivity and decoherence rate to numerical
renormalization group results. By exploiting non-Abelian symmetries we show
improved numerical data for both quantities as compared to previous
calculations [Costi et al., Phys. Rev. Lett. 102, 056802 (2009)], using the
discarded weight as criterion to reliably judge the quality of convergence of
the numerical data. In addition we also carry out finite-temperature
calculations for the magnetoresistivity of fully screened Kondo models with S =
1/2, 1 and 3/2, and compare the results with available measurements for iron in
silver, finding excellent agreement between theory and experiment for the
spin-3/2 three-channel Kondo model. This lends additional support to the
conclusion of Costi et al. that the latter model provides a good effective
description of the Kondo physics of iron impurities in gold and silver.


title:
Multi-resonance orbital model of high-frequency quasi-periodic
  oscillations: possible high-precision determination of black hole and neutron
  star spin

abstract:
  Using known frequencies of the twin-peak high-frequency quasiperiodic
oscillations (HF QPOs) and known mass of the central black hole, the black-hole
dimensionless spin can be determined by assuming a concrete version of the
resonance model. However, a wide range of observationally limited values of the
black hole mass implies low precision of the spin estimates. We discuss the
possibility of higher precision of the black hole spin measurements in the
framework of a multi-resonance model inspired by observations of more than two
HF QPOs in the black hole systems, which are expected to occur at two (or more)
different radii of the accretion disc. For the black hole systems we focus on
the special case of duplex frequencies, when the top, bottom, or mixed
frequency is common at two different radii where the resonances occur giving
triple frequency sets. The sets of triple frequency ratios and the related spin
are given. The strong resonance model for "magic" values of the black hole spin
means that two (or more) versions of resonance could occur at the same radius,
allowing cooperative effects between the resonances. For neutron star systems
we introduce a resonant switch model that assumes switching of oscillatory
modes at resonant points. In the case of doubled twin-peak HF QPOs excited at
two different radii with common top, bottom, or mixed frequency, the black hole
spin is given by the triple frequency ratio set. The spin is determined
precisely, but not uniquely, because the same frequency set could correspond to
more than one concrete spin. The black hole mass is given by the magnitude of
the observed frequencies. The resonant switch model puts relevant limits on the
mass and spin of neutron stars, and we expect a strong increase in the fitting
procedure precision when different twin oscillatory modes are applied to data
in the vicinity of different resonant points.


title: Maxwell's demon for calcium binding to calmodulin?

abstract:
  In the recent paper (2011) Faas and co-workers claimed that calmodulin could
directly detect Ca2+ signals by acting as extremely fast calcium buffer.
However the results and their interpretation raise serious doubts about this
conclusion.


title:
Integration and characterization of solid wall electrodes in
  microfluidic devices fabricated in a single photolithography step

abstract:
  We describe the fabrication and characterization of solid 3-dimensional
electrodes in direct contact with microfluidic channels, implemented using a
single photolithography step, allowing operation in high-dielectric constant
media. Incorporation and self-alignment of electrodes is achieved by combining
microsolidic approaches with exploitation of the surface tension of low melting
point alloys. Thus the metal forms the walls flanking the channel. We show that
this approach yields electrodes with a well-defined, reproducible morphology
and stable electronic properties when in contact with biochemical buffers. By
combining calibration of the electric field with free-flow electrophoresis we
quantify the net solvated charges of small molecules.


title:
The hard pomeron intercept and the data on the proton unpolarized
  structure function

abstract:
  It is demonstrated that the hard pomeron intercept value can be estimated
directly from the data on the proton unpolarized structure function:
$\alpha_{\rm P}^h(0)-1=0.317\pm 0.028$.


title: Viral genome structures are optimal for capsid assembly

abstract:
  Understanding how virus capsids assemble around their nucleic acid (NA)
genomes could promote efforts to block viral propagation or to reengineer
capsids for gene therapy applications. We develop a coarse-grained model of
capsid proteins and NAs with which we investigate assembly dynamics and
thermodynamics. In contrast to recent theoretical models, we find that capsids
spontaneously `overcharge'; i.e., the negative charge of the NA exceeds the
positive charge on capsid. When applied to specific viruses, the optimal NA
lengths closely correspond to the natural genome lengths. Calculations based on
linear polyelectrolytes rather than base-paired NAs underpredict the optimal
length, demonstrating the importance of NA structure to capsid assembly. These
results suggest that electrostatics, excluded volume, and NA tertiary structure
are sufficient to predict assembly thermodynamics and that the ability of
viruses to selectively encapsidate their genomic NAs can be explained, at least
in part, on a thermodynamic basis.


title: A review of Axion Inflation in the era of Planck

abstract:
  Because the inflationary mechanism is extremely sensitive to UV-physics, the
construction of theoretically robust models of inflation provides a unique
window on Planck-scale physics. We review efforts to use an axion with a shift
symmetry to ensure a prolonged slow-roll background evolution. The symmetry
dictates which operators are allowed, and these in turn determine the
observational predictions of this class of models, which include observable
gravitational waves (potentially chiral), oscillations in all primordial
correlators, specific deviations from scale invariance and Gaussianity and
primordial black holes. We discuss the constraints on this class of models in
light of the recent Planck results and comment on future perspectives. The
shift symmetry is very useful in models of large-field inflation, which
typically have monomial potentials, but it cannot explain why two or more terms
in the potential are fine-tuned against each other, as needed for typical
models of small-field inflation. Therefore some additional symmetries or
fine-tuning will be needed if forthcoming experiments will constrain the
tensor-to-scalar ratio to be r < 0.01.


title:
Termination dependent topological surface states of the natural
  superlattice phase Bi$_4$Se$_3$

abstract:
  We describe the topological surface states of Bi$_4$Se$_3$, a compound in the
infinitely adaptive Bi$_2$-Bi$_2$Se$_3$ natural superlattice phase series,
determined by a combination of experimental and theoretical methods. Two
observable cleavage surfaces, terminating at Bi or Se, are characterized by
angle resolved photoelectron spectroscopy and scanning tunneling microscopy,
and modeled by ab-initio density functional theory calculations. Topological
surface states are observed on both surfaces, but with markedly different
dispersions and Kramers point energies. Bi$_4$Se$_3$ therefore represents the
only known compound with different topological states on differently terminated
surfaces.


title: A Deterministic Affine-Quadratic Optimal Control Problem

abstract:
  A Deterministic affine quadratic optimal control problem is considered. Due
to the nature of the problem, optimal controls exist under some very mild
conditions. Further, it is shown that under some assumptions, the value
function is differentiable and therefore satisfies the corresponding
Hamilton-Jacobi-Bellman equation in the classical sense. Moreover, the
so-called quasi-Riccati equation is derived and any optimal control admits a
state feedback representation.


title: The BABAR Detector: Upgrades, Operation and Performance

abstract:
  The BABAR detector operated successfully at the PEP-II asymmetric e+e-
collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This
report covers upgrades, operation, and performance of the collider and the
detector systems, as well as the trigger, online and offline computing, and
aspects of event reconstruction since the beginning of data taking.


title: The Beta-Wishart Ensemble

abstract:
  This paper proves a matrix model for the Wishart Ensemble with general
covariance and general dimension parameter beta. In so doing, we introduce a
new and elegant definition of Jack polynomials.


title:
Non-limit integration of differential equations. General solution for
  van der Pol equation

abstract:
  Using the physical background based on the earlier author's researches the
new method of the ODE and PDE integration is proposed. As illustrations of the
method the general solution for free oscillator and for heat equation are
derived. As a result of the article the general solution for van der Pol
equation is given.


title:
Low concentrated hydroxyectoine solutions in presence of DPPC lipid
  bilayers: a computer simulation study

abstract:
  The influence of hydroxyectoine on the properties of the aqueous solution in
presence of DPPC lipid bilayers is studied via semi-isotropic constant pressure
(NPT) Molecular Dynamics simulations. We investigate the solvent-co-solute
behavior in terms of Kirkwood-Buff integrals as well as hydrogen bond life
times for an increasing hydroxyectoine concentration up to 0.148 mol/L. The
observed preferential exclusion mechanism identifies hydroxyectoine as a
kosmotropic osmolyte. Our findings in regards to the DPPC lipid bilayer
indicate an increase of the surface pressure as well as the solvent accessible
surface area in presence of higher hydroxyectoine concentrations. The results
are in agreement to the outcome of recent experiments. With this study, we are
able to validate the visibility of co-solute-solute-solvent effects for low and
physiologically relevant osmolyte concentrations.

categories: physics.bio-ph cond-mat.soft physics.chem-ph q-bio.BM


title: Phase diagram of the 4D U(1) model at finite temperature

abstract:
  We explore the phase diagram of the 4D compact U(1) gauge theory at finite
temperature as a function of the gauge coupling and of the compactified
Euclidean time dimension L_t. We show that the strong-to-weak coupling
transition, which is first order at T=0 (L_t=\infty), becomes second order for
high temperatures, i.e. for small values of L_t, with a tricritical temporal
size \bar{L_t} located between 5 and 6. The critical behavior around the
tricritical point explains and reconciles previous contradictory evidences
found in the literature.


title: Optical waveguide arrays: quantum effects and PT symmetry breaking

abstract:
  Over the last two decades, advances in fabrication have led to significant
progress in creating patterned heterostructures that support either carriers,
such as electrons or holes, with specific band structure or electromagnetic
waves with a given mode structure and dispersion. In this article, we review
the properties of light in coupled optical waveguides that support specific
energy spectra, with or without the effects of disorder, that are
well-described by a Hermitian tight-binding model. We show that with a
judicious choice of the initial wave packet, this system displays the
characteristics of a quantum particle, including transverse photonic transport
and localization, and that of a classical particle. We extend the analysis to
non-Hermitian, parity and time-reversal ($\mathcal{PT}$) symmetric Hamiltonians
which physically represent waveguide arrays with spatially separated, balanced
absorption or amplification. We show that coupled waveguides are an ideal
candidate to simulate $\mathcal{PT}$-symmetric Hamiltonians and the transition
from a purely real energy spectrum to a spectrum with complex conjugate
eigenvalues that occurs in them.


title: Combinatorics of tight geodesics and stable lengths

abstract:
  We give an algorithm to compute the stable lengths of pseudo-Anosovs on the
curve graph, answering a question of Bowditch. We also give a procedure to
compute all invariant tight geodesic axes of pseudo-Anosovs.
  Along the way we show that there are constants $1<a_1<a_2$ such that the
minimal upper bound on `slices' of tight geodesics is bounded below and above
by $a_1^{\xi(S)}$ and $a_2^{\xi(S)}$, where $\xi(S)$ is the complexity of the
surface. As a consequence, we give the first computable bounds on the
asymptotic dimension of curve graphs and mapping class groups.
  Our techniques involve a generalization of Masur--Minsky's tight geodesics
and a new class of paths on which their tightening procedure works.


title: Hyperbolic sets that are not contained in a locally maximal one

abstract:
  In this paper we study two properties related to the structure of hyperbolic
sets. First we construct new examples answering in the negative the following
question posed by Katok and Hasselblatt. Let $\Lambda$ be a hyperbolic set, and
let $V$ be an open neighborhood of $\Lambda$. Does there exist a locally
maximal hyperbolic set $\widetilde{\Lambda}$ such that $\Lambda \subset
\widetilde{\Lambda} \subset V $? We show that such examples are present in
linear anosov diffeomorophisms of $\mathbb{T}^3$, and are therefore robust.
Also we construct new examples of sets that are not contained in any locally
maximal hyperbolic set. The examples known until now were constructed by
Crovisier and by Fisher, and these were either in dimension bigger than 4 or
they were not transitive. We give a transitive and robust example in
$\mathbb{T}^3$. And show that such examples cannot be build in dimension 2.


title: SoftCell: Taking Control of Cellular Core Networks

abstract:
  Existing cellular networks suffer from inflexible and expensive equipment,
and complex control-plane protocols. To address these challenges, we present
SoftCell, a scalable architecture for supporting fine-grained policies for
mobile devices in cellular core networks. The SoftCell controller realizes
high-level service polices by directing traffic over paths that traverse a
sequence of middleboxes, optimized to the network conditions and user
locations. To ensure scalability, the core switches forward traffic on
hierarchical addresses (grouped by base station) and policy tags (identifying
paths through middleboxes). This minimizes data-plane state in the core
switches, and pushes all fine-grained state to software switches at the base
stations. These access switches apply fine-grained rules, specified by the
controller, to map all traffic to the appropriate addresses and tags. SoftCell
guarantees that packets in the same connection traverse the same sequence of
middleboxes in both directions, even in the presence of mobility. Our
characterization of real LTE workloads, micro-benchmarks on our prototype
controller, and large-scale simulations demonstrate that SoftCell improves the
flexibility of cellular core networks, while enabling the use of inexpensive
commodity switches and middleboxes.


title: Log canonical pairs with good augmented base loci

abstract:
  Let $(X,B)$ be a projective log canonical pair such that $B$ is a
$\Q$-divisor, and that there is a surjective morphism $f\colon X\to Z$ onto a
normal variety $Z$ satisfying: $K_X+B\sim_\Q f^*M$ for some $\Q$-divisor $M$,
and the augmented base locus ${\bf{B_+}}(M)$ does not contain the image of any
log canonical centre of $(X,B)$. We will show that $(X,B)$ has a good log
minimal model. An interesting special case is when $f$ is the identity
morphism.


title: New measures of graph irregularity

abstract:
  In this paper, we define and compare four new measures of graph irregularity.
We use these measures to prove upper bounds for the chromatic number and the
Colin de Verdiere parameter. We also strengthen the concise Turan theorem for
irregular graphs and investigate to what extent Turan's theorem can be
similarly strengthened for generalized r-partite graphs. We conclude by
relating these new measures to the Randic index and using the measures to
devise new normalised indices of network heterogeneity.


title:
Competing orders in the 2D half-filled SU(2N) Hubbard model through the
  pinning field quantum Monte-Carlo simulations

abstract:
  We non-perturbatively investigate the ground state magnetic properties of the
2D half-filled SU($2N$) Hubbard model in the square lattice by using the
projector determinant quantum Monte Carlo simulations combined with the method
of local pinning fields. Long-range Neel orders are found for both the SU(4)
and SU(6) cases at small and intermediate values of $U$. In both cases, the
long-range Neel moments exhibit non-monotonic behavior with respect to $U$,
which first grow and then drop as $U$ increases. This result is fundamentally
different from the SU(2) case in which the Neel moments increase monotonically
and saturate. In the SU(6) case, a transition to the columnar dimer phase is
found in the strong interaction regime.


title: Relative Geodesics in the Special Euclidean Group

abstract:
  We propose a notion of distance between two parametrized planar curves,
called their discrepancy, and defined intuitively as the minimal amount of
deformation needed to deform the source curve into the target curve. A precise
definition of discrepancy is given as follows. A curve of transformations in
the special Euclidean group SE(2) is said to be admissible if it maps the
source curve to the target curve under the point-wise action of SE(2) on the
plane. After endowing the group SE(2) with a left-invariant metric, we define a
relative geodesic in SE(2) to be a critical point of the energy functional
associated to the metric, over all admissible curves. The discrepancy is then
defined as the value of the energy of the minimizing relative geodesic. In the
first part of the paper, we derive a scalar ODE which is a necessary condition
for a curve in SE(2) to be a relative geodesic, and we discuss some of the
properties of the discrepancy. In the second part of the paper, we consider
discrete curves, and by means of a variational principle, we derive a system of
discrete equations for the relative geodesics. We finish with several examples.


title: Long-term monitoring of PKS0558-504 with Swift: the disc-corona link

abstract:
  PKS 0558-504 is a highly variable, X-ray bright, radio-loud, Narrow-Line
Seyfert 1 galaxy with super-Eddington accretion rate and extended jets that do
not dominate the emission beyond the radio band. Therefore, this source
represents an ideal laboratory to shed some light on the central engine in
highly accreting systems and specifically on the link between accretion disc
and corona. Here we present the results from a 1.5 year monitoring with Swift
XRT and UVOT. The simultaneous coverage at several wavelengths confirms that
PKS 0558-504 is highly variable in any band from optical, to UV and X-rays,
with the latter showing the largest amplitude changes but with the UV emission
dominating the radiative output. A cross-correlation analysis reveals a tight
link between the emission in the optical and UV bands and provides suggestive
evidence in favor of a scenario where the variability originates in the outer
part of the accretion flow and propagates inwards before triggering the
activity of the X-ray emitting corona. Finally, a positive correlation between
the soft X-ray flux and the hard photon index suggests that in PKS 0558-504 the
seed photons are provided to the corona by the soft excess component.


title: A strongly coupled zig-zag transition

abstract:
  The zig-zag symmetry transition is a phase transition in 1D quantum wires, in
which a Wigner lattice of electrons transitions to two staggered lattices.
Previous studies model this transition as a Luttinger liquid coupled to a
Majorana fermion. The model exhibits interesting RG flows, involving quenching
of velocities in subsectors of the theory. We suggest an extension of the model
which replaces the Majorana fermion by a more general CFT; this includes an
experimentally realizable case with two Majorana fermions. We analyse the RG
flow both in field theory and using AdS/CFT techniques in the large central
charge limit of the CFT. The model has a rich phase structure with new
qualitative features, already in the two Majorana fermion case. The AdS/CFT
calculation involves considering back reaction in space-time to capture
subleading effects.


title: Halo-independent methods for inelastic dark matter scattering

abstract:
  We present halo-independent methods to analyze the results of dark matter
direct detection experiments assuming inelastic scattering. We focus on the
annual modulation signal reported by DAMA/LIBRA and present three different
halo-independent tests. First, we compare it to the upper limit on the
unmodulated rate from XENON100 using (a) the trivial requirement that the
amplitude of the annual modulation has to be smaller than the bound on the
unmodulated rate, and (b) a bound on the annual modulation amplitude based on
an expansion in the Earth's velocity. The third test uses the special
predictions of the signal shape for inelastic scattering and allows for an
internal consistency check of the data without referring to any astrophysics.
We conclude that a strong conflict between DAMA/LIBRA and XENON100 in the
framework of spin-independent inelastic scattering can be established
independently of the local properties of the dark matter halo.


title:
WFC3 grism confirmation of the distant cluster Cl J1449+0856 at z=2.00:
  Quiescent and star-forming galaxy populations

abstract:
  We present deep Hubble Space Telescope Wide Field Camera 3 slitless
spectroscopic observations of the distant cluster Cl J1449+0856. These cover a
single pointing with 18 orbits of G141 spectroscopy and F140W imaging, allowing
us to derive secure redshifts down to m_140~25.5 AB and 3sigma line fluxes of
5*10^(-18) erg/s/cm^2. In particular, we were able to spectroscopically confirm
12 early-type galaxies in the field up to z~3, 6 of which in the cluster core,
which represents the first direct spectroscopic confirmation of passive
galaxies in a z=2 cluster environment. With 140 redshifts in a ~6 arcmin^2
field, we can trace the spatial and redshift galaxy distribution in the cluster
core and background field. We find two strong peaks at z=2.00 and z=2.07, where
only one was seen in our previously published ground-based data. Thanks to the
spectroscopic confirmation of the cluster ETGs, we can now re-evaluate the
redshift of Cl J1449+0856 at z=2.00, rather than z=2.07, with the background
overdensity being revealed to be sparse and "sheet"-like. This presents an
interesting case of chance alignment of two close yet unrelated structures,
each one preferentially selected by different observing strategies. With 6
quiescent or early-type spectroscopic members and 20 star-forming ones, Cl
J1449+0856 is now reliably confirmed to be at z=2.00. The identified members
can now allow for a detailed study of galaxy properties in the densest
environment at z=2.


title:
Galaxy evolution in overdense environments at high redshift: passive
  early-type galaxies in a cluster at redshift 2

abstract:
  We present a study of galaxy populations in the central region of the
IRAC-selected, X-ray detected galaxy cluster Cl J1449+0856 at z=2. Based on a
sample of spectroscopic and photometric cluster members, we investigate stellar
populations and morphological structure of cluster galaxies over an area of
~0.7Mpc^2 around the cluster core. The cluster stands out as a clear
overdensity both in redshift space, and in the spatial distribution of galaxies
close to the center of the extended X-ray emission. The cluster core region
(r<200 kpc) shows a clearly enhanced passive fraction with respect to field
levels. However, together with a population of massive passive galaxies mostly
with early-type morphologies, it also hosts massive actively star-forming,
often highly dust-reddened sources. Close to the cluster center, a
multi-component system of passive and star-forming galaxies could be the future
BCG still assembling. We observe a clear correlation between passive stellar
populations and an early-type morphology, in agreement with field studies at
similar redshift. Passive early-type galaxies in this clusters are typically a
factor 2-3 smaller than similarly massive early-types at z~0, but also on
average larger by a factor ~2 than their field analogs at z~2, lending support
to recent claims of an accelerated structural evolution in high-redshift dense
environments. These results point towards the early formation of a population
of massive galaxies, already evolved both in their structure and stellar
populations, coexisting with still-actively forming massive galaxies in the
central regions of young clusters 10 billion years ago.


title: Search in Random Media with L\'evy Flights

abstract:
  We review some of our work regarding search which has been motivated by a
variety of applications in engineering and technology, including traffic
routing and security in communication networks, explosive mine detection and
removal, tactical operations as well as emergency management. We develop the
basic mathematical model representing N searchers that proceed independently,
and which can be affected by destruction or loss, and time-outs. An approach
based on Laplace transform is then developed for the case where the success of
the search requires that k out of the N searchers be successful, and we
estimate the amount of energy expended and the number of searchers that are
required to conduct a successful search in time B, provided B is large.
Finally, we present an iterative numerical solution approach that allows us to
analyse the search time and the energy needed to find an object when the search
space is non-homogeneous.


title: Sensitivity to perturbations and quantum phase transitions

abstract:
  The local density of states or its Fourier transform, usually called fidelity
amplitude, are important measures of quantum irreversibility due to imperfect
evolution. In this Rapid Communication we study both quantities in a
paradigmatic many body system, the Dicke Hamiltonian, where a single-mode
bosonic field interacts with an ensemble of N two-level atoms. This model
exhibits a quantum phase transition in the thermodynamic limit, while for
finite instances the system undergoes a transition from quasi-integrability to
quantum chaotic. We show that the width of the local density of states clearly
points out the imprints of the transition from integrability to chaos but no
trace remains of the quantum phase transition. The connection with the decay of
the fidelity amplitude is also established.


title: Carmichael numbers in the sequence (k2^n+1)_{n\ge 1}

abstract:
  We prove that for each odd number k, the sequence (k2^n+1)_{n\ge 1} contains
only a finite number of Carmichael numbers. We also prove that k=27 is the
smallest value for which such a sequence contains some Carmichael number.


title:
The Dependence of Alloy Composition of InGaAs Inserts in GaAs
  Nanopillars on Selective-Area Pattern Geometry

abstract:
  GaAs nanopillars with 150 nm - 200 nm long axial InGaAs inserts are grown by
MOCVD via catalyst-free selective-area-epitaxy (SAE). The alloy composition of
the InGaAs region, as determined by room-temperature photoluminescence (PL),
depends critically on the pitch and diameter of the selective-area pattern
geometry. The PL emission varies based on pattern geometry from 1.0 \{mu}m to
1.25 \{mu}m corresponding to a In to Ga ratio from 0.15 to > 0.3. This In
enrichment is explained by a pattern dependent change in the incorporation rate
for In and Ga. Capture coefficients for Ga and In adatoms are calculated for
each pattern pitch. As the pitch decreases, these data reveal a contest between
a synergetic effect (related to nanopillar density) that increases the growth
rate and a competition for available material that limits the growth rate.
Gallium is more susceptible to both of these effects, causing the observed
changes in alloy composition.


title: Thermodynamics of continua: the challenge of universality

abstract:
  The explanation of the apparent universality of thermodynamics points toward
the extension of the usual conceptual background of the second law. Arguments
are collected that a basic guiding idea of stability of thermodynamic
equilibrium combined with a proper interpretation of the entropy principle may
provide the necessary solid foundation with verifiable consequences.


title: Experimental aspects of heat conduction beyond Fourier

abstract:
  Heat conduction experiments are performed in order to identify effects beyond
Fourier. Two experimental setups are discussed. First, a simple experiment by a
heterogeneous material is investigated from the point of view of generalized
heat conduction, then the classical laser flash method is analysed.


title: New Greedy Heuristics For Set Cover and Set Packing

abstract:
  The Set Cover problem (SCP) and Set Packing problem (SPP) are standard
NP-hard combinatorial optimization problems. Their decision problem versions
are shown to be NP-Complete in Karp's 1972 paper. We specify a rough guide to
constructing approximation heuristics that may have widespread applications and
apply it to devise greedy approximation algorithms for SCP and SPP, where the
selection heuristic is a variation of that in the standard greedy approximation
algorithm. Our technique involves assigning to each input set a valuation and
then selecting, in each round, the set whose valuation is highest. We prove
that the technique we use for determining a valuation of the input sets yields
a unique value for all Set Cover instances. For both SCP and SPP we give
experimental evidence that the valuations we specify are unique and can be
computed to high precision quickly by an iterative algorithm. Others have
experimented with testing the observed approximation ratio of various
algorithms over a variety of randomly generated instances, and we have
extensive experimental evidence to show the quality of the new algorithm
relative to greedy heuristics in common use. Our algorithms are somewhat more
computationally intensive than the standard heuristics, though they are still
practical for large instances. We discuss some ways to speed up our algorithms
that do not significantly distort their effectiveness in practice on random
instances.


title:
Bayesian Functional Generalized Additive Models with Sparsely Observed
  Covariates

abstract:
  The functional generalized additive model (FGAM) was recently proposed in
McLean et al. (2013) as a more flexible alternative to the common functional
linear model (FLM) for regressing a scalar on functional covariates. In this
paper, we develop a Bayesian version of FGAM for the case of Gaussian errors
with identity link function. Our approach allows the functional covariates to
be sparsely observed and measured with error, whereas the estimation procedure
of McLean et al. (2013) required that they be noiselessly observed on a regular
grid. We consider both Monte Carlo and variational Bayes methods for fitting
the FGAM with sparsely observed covariates. Due to the complicated form of the
model posterior distribution and full conditional distributions, standard Monte
Carlo and variational Bayes algorithms cannot be used. The strategies we use to
handle the updating of parameters without closed-form full conditionals should
be of independent interest to applied Bayesian statisticians working with
nonconjugate models. Our numerical studies demonstrate the benefits of our
algorithms over a two-step approach of first recovering the complete
trajectories using standard techniques and then fitting a functional regression
model. In a real data analysis, our methods are applied to forecasting closing
price for items up for auction on the online auction website eBay.


title:
Utility Optimal Scheduling and Admission Control for Adaptive Video
  Streaming in Small Cell Networks

abstract:
  We consider the jointly optimal design of a transmission scheduling and
admission control policy for adaptive video streaming over small cell networks.
We formulate the problem as a dynamic network utility maximization and observe
that it naturally decomposes into two subproblems: admission control and
transmission scheduling. The resulting algorithms are simple and suitable for
distributed implementation. The admission control decisions involve each user
choosing the quality of the video chunk asked for download, based on the
network congestion in its neighborhood. This form of admission control is
compatible with the current video streaming technology based on the DASH
protocol over TCP connections. Through simulations, we evaluate the performance
of the proposed algorithm under realistic assumptions for a small-cell network.


title: Perimeter-minimizing Tilings by Convex and Non-convex Pentagons

abstract:
  We study the presumably unnecessary convexity hypothesis in the theorem of
Chung et al. [CFS] on perimeter-minimizing planar tilings by convex pentagons.
We prove that the theorem holds without the convexity hypothesis in certain
special cases, and we offer direction for future research.


title: D-meson lifetimes within the heavy quark expansion

abstract:
  Even if new data indicate that direct CP violation in D-meson decays is
compatible with the standard model expectation, it has triggered a lot of
interest, and charm phenomenology will remain an essential part of new physics
searches due to its unique role as a probe for flavor-changing neutral currents
among up-type quarks. Charm physics poses considerable theoretical challenges,
because the charm mass is neither light nor truly heavy. The heavy quark
expansion (HQE) provides a perturbative expansion in the inverse heavy quark
mass for inclusive rates. It has proved to be very successful in the B sector,
yet its validity for charm decays has often been questioned. We present results
of a HQE study of D-meson lifetimes including NLO QCD and subleading 1/m_c
corrections. We find good agreement with experimental data, but with huge
hadronic uncertainties due to missing lattice input for hadronic matrix
elements.


title:
Energy Dependence of Profile Functions in $\rm{p\bar p}$ and $\rm pp$
  Scattering

abstract:
  We construct analytical forms in the impact parameter $b$-space for the real
and imaginary amplitudes describing elastic pp and $\rm p \bar p $ scattering.
The amplitudes converted analytically to the momentum transfer $t$-space have
magnitudes, slopes, curvatures, zeros, signs, obeying phenomenological and
theoretical expectations, and describe with high precision all details of the
data, in the full-t range, and for energies from 20 GeV to 7 TeV. The
connection of forward with large-$|t|$ behavior allows precise determination of
total cross-sections, slopes and other scattering parameters. We study the
properties and the energy dependence of the $b$-space profile functions,
observing that the real part has fundamental influence in the structure of
$d\sigma/dt$ at intermediate and large $|t|$ values. We discuss the 540/546 GeV
and 1.8/1.96 TeV data from CERN SPS and Fermilab TEVATRON and the 7 TeV results
from TOTEM measurements at LHC, and investigate the extrapolation to 14 TeV and
higher energies.


title:
Design and Performance Analysis of a 2.5 MW-Class HTS Synchronous Motor
  for Ship Propulsion

abstract:
  The development of cryogenic technology and high temperature superconducting
(HTS) materials has seen continued interest worldwide in the development of HTS
machines since the late 1980s. In this paper, the authors present a conceptual
design of a 2.5 MW class synchronous motor. The structure of the motor is
specified and the motor performance is analyzed via a three-dimensional model
using the finite element method (FEM). Rotor optimization is carried out to
decrease the harmonic components in the air gap field generated by HTS tapes.
Based on the results of this 3D simulation, the determination of the operating
conditions and load angle is discussed with consideration to the HTS material
properties. The economic viability of air-core and iron-core designs is
compared. The results show that this type of HTS machine has the potential to
achieve an economic, efficient and effective machine design, which operates at
a low load angle, and this design process provides a practical way to simulate
and analyze the performance of such machines.


title:
On a Time-Space Operator (and other Non-Selfadjoint Operators) for
  Observables in QM and QFT

abstract:
  Aim of this paper is trying to show the possible significance, and
usefulness, of various non-selfadjoint operators for suitable Observables in
non-relativistic and relativistic quantum mechanics, and in quantum
electrodynamics: More specifically, this work starts dealing with: (i) the
hermitian (but not selfadjoint) Time operator in non-relativistic quantum
mechanics and in quantum electrodynamics; with (ii) idem, with the introduction
of Time and Space operators; and with (iii) the problem of the four-position
and four-momentum operators, each one with its hermitian and anti-hermitian
parts, for relativistic spin-zero particles. Afterwards, other physical
applications of non-selfadjoint (and even non-hermitian) operators are briefly
discussed. We mention how non-hermitian operators can indeed be used in physics
[as it was done, elsewhere, for describing Unstable States]; and some
considerations are added on the cases of the nuclear optical potential, of
quantum dissipation, and in particular of an approach to the measurement
problem in QM in terms of a "chronon". [This chapter is largely based on work
developed, along the years, in collaboration with V.S.Olkhovsky, and, in
smaller parts, with P.Smrz, with R.H.A.Farias, and with S.P.Maydanyuk]. PACS
numbers: 03.65.Ta; 03.65.-w; 03.65.Pm; 03.70.+k; 03.65.Xp; 03.65.Yz; 11.10.St;
11.10.-z; 11.90.+t; 02.00.00; 03.00.00; 24.10.Ht; 03.65.Yz; 21.60.-u; 11.10.Ef;
03.65.Fd; 02.40.Dr; 98.80.Jk. Keywords: time operator, space-time operator,
non-selfadjoint operators, non-hermitian operators, bilinear operators, time
operator for discrete energy spectra, time-energy uncertainty relations,
Klein-Gordon equation, chronon, quantum dissipation, decoherence, nuclear
optical model, cosmology, projective relativity.


title: Linear Optical Quantum Computing in a Single Spatial Mode

abstract:
  We present a scheme for linear optical quantum computing using time-bin
encoded qubits in a single spatial mode. We show methods for single-qubit
operations and heralded controlled phase (CPhase) gates, providing a sufficient
set of operations for universal quantum computing with the
Knill-Laflamme-Milburn scheme. Our scheme is suited to available photonic
devices and ideally allows arbitrary numbers of qubits to be encoded in the
same spatial mode, demonstrating the potential for time-frequency modes to
dramatically increase the quantum information capacity of fixed spatial
resources. As a test of our scheme, we demonstrate the first entirely single
spatial mode implementation of a two-qubit quantum gate and show its operation
with an average fidelity of 0.84+-0.07.


title:
Statistics of multiple-scatterer induced frequency splitting in
  whispering gallery microresonators and microlasers

abstract:
  We investigate numerically and experimentally the statistics of the changes
in the amount of frequency splitting upon the adsorption of particles
one-by-one into the mode volume of whispering gallery mode (WGM) microresonator
and microlasers. This multiple-particle induced frequency splitting (MPIFS)
statistics carries information on the size and the number of adsorbed particles
into the mode volume, and it is strongly affected by two experimental
parameters, namely the WGM field distribution and the positions of the
particles within the mode volume. We show that the standard deviation and
maximum value of the MPIFS are proportional to the polarizability of the
particles, and propose a method to estimate particle size from the MPIFS if the
only available data from experiments is frequency splitting.


title: Unitary realization of wavefunction collapse

abstract:
  Recent quantum reconstruction projects demand pure unitary time evolution
which seems to contradict the collapse postulate. A natural unitary realization
of wavefunction collapse is built using Grothendick group construction for the
tensor product commutative monoid. Envariance and quantum Darwinism are key
ingredients in the proof.


title: Binary Energy Harvesting Channel with Finite Energy Storage

abstract:
  We consider the capacity of an energy harvesting communication channel with a
finite-sized battery. As an abstraction of this problem, we consider a system
where energy arrives at the encoder in multiples of a fixed quantity, and the
physical layer is modeled accordingly as a finite discrete alphabet channel
based on this fixed quantity. Further, for tractability, we consider the case
of binary energy arrivals into a unit-capacity battery over a noiseless binary
channel. Viewing the available energy as state, this is a state-dependent
channel with causal state information available only at the transmitter.
Further, the state is correlated over time and the channel inputs modify the
future states. We show that this channel is equivalent to an additive
geometric-noise timing channel with causal information of the noise available
at the transmitter.We provide a single-letter capacity expression involving an
auxiliary random variable, and evaluate this expression with certain auxiliary
random variable selection, which resembles noise concentration and lattice-type
coding in the timing channel. We evaluate the achievable rates by the proposed
auxiliary selection and extend our results to noiseless ternary channels.


title:
Robust Streaming Erasure Codes based on Deterministic Channel
  Approximations

abstract:
  We study near optimal error correction codes for real-time communication. In
our setup the encoder must operate on an incoming source stream in a sequential
manner, and the decoder must reconstruct each source packet within a fixed
playback deadline of $T$ packets. The underlying channel is a packet erasure
channel that can introduce both burst and isolated losses.
  We first consider a class of channels that in any window of length ${T+1}$
introduce either a single erasure burst of a given maximum length $B,$ or a
certain maximum number $N$ of isolated erasures. We demonstrate that for a
fixed rate and delay, there exists a tradeoff between the achievable values of
$B$ and $N,$ and propose a family of codes that is near optimal with respect to
this tradeoff. We also consider another class of channels that introduce both a
burst {\em and} an isolated loss in each window of interest and develop the
associated streaming codes.
  All our constructions are based on a layered design and provide significant
improvements over baseline codes in simulations over the Gilbert-Elliott
channel.


title:
Single Electron Dynamics of an Atomic Silicon Quantum Dot on the
  H-Si(100) 2x1 Surface

abstract:
  Here we report the direct observation of single electron charging of a single
atomic Dangling Bond (DB) on the H-Si(100) 2x1 surface. The tip of a scanning
tunneling microscope is placed adjacent to the DB to serve as a single electron
sensitive charge-detector. Three distinct charge states of the dangling bond,
positive, neutral, and negative, are discerned. Charge state probabilities are
extracted from the data, and analysis of current traces reveals the
characteristic single electron charging dynamics. Filling rates are found to
decay exponentially with increasing tip-DB separation, but are not a function
of sample bias, while emptying rates show a very weak dependence on tip
position, but a strong dependence on sample bias, consistent with the notion of
an atomic quantum dot tunnel coupled to the tip on one side and the bulk
silicon on the other.


title: Partial-wave analysis of $\bar K N$ scattering reactions

abstract:
  We investigate the two-body reactions $\bar K N\rightarrow \bar K N$, $\bar K
N\rightarrow \pi \Lambda$, and $\bar K N\rightarrow \pi \Sigma$ via
single-energy partial-wave analyses in the c.m.\ energy range 1480 to 2100 MeV.
The partial-wave amplitudes for these reactions thus extracted were constrained
by a multichannel energy-dependent model satisfying unitarity of the
partial-wave $S$-matrix. We obtain excellent predictions of differential cross
sections, polarizations, polarized cross sections, and cross sections for these
reactions from a global energy-dependent solution.


title:
Diffraction via Pomeron and photon exchanges using proton tagging at the
  LHC

abstract:
  We present some physics topics that can be studied at the LHC using proton
tagging. We distinguish the QCD (Pomeron structure, BFKL analysis...) from the
exploratory physics topics (HIggs boson, anomalous couplings between photons
and $W/Z$ bosons)


title:
An Entourage Approach to the Contraction Principle in Uniform Spaces
  Endowed with a Graph

abstract:
  In this paper, we study Banach contractions in uniform spaces endowed with a
graph and give some sufficient conditions for a mapping to be a Picard
operator. Our main results generalize some results of [J. Jachymski, "The
contraction principle for mappings on a metric space with a graph", Proc. Amer.
Math. Soc. 136 (2008) 1359-1373] employing the basic entourages of the uniform
space.


title: Tevatron Combination and Higgs Boson Properties

abstract:
  We present the Tevatron combination of searches for the Higgs boson and
studies of its properties. The searches use up to 10 fb$^{-1}$ of Tevatron
collider Run II data. We observe a significant excess of events in the mass
range between 115 and 140 GeV/c$^2$. The local significance corresponds to 3
Gaussian standard deviations at the mass of 125 GeV/c$^2$. Furthermore, we
separately combine searches for the Higgs boson decaying to $b\bar b$,
$\tau^+\tau^-$, $W^+W^-$, and photon pairs in the final states. The observed
signal strengths in all channels are consistent with the presence of a standard
model scalar boson with a mass of 125 GeV/c$^2$. Studies of the couplings at
the Tevatron are consistent with SM predictions and are complementary to those
performed at LHC.


title:
Would be the photon a composed particle? quantization of field fluxes in
  electromagnetic radiation

abstract:
  [En] Here it is made a comparative analysis between the classical and the
quantum expressions for the energy of electromagnetic radiation (ER). The
comparison points to the possibility of the quantization of the magnetic and
the electric field fluxes in the ER.


title: Searching for a 0.1-1 keV Cosmic Axion Background

abstract:
  Primordial decays of string theory moduli at z \sim 10^{12} naturally
generate a dark radiation Cosmic Axion Background (CAB) with 0.1 - 1 keV
energies. This CAB can be detected through axion-photon conversion in
astrophysical magnetic fields to give quasi-thermal excesses in the extreme
ultraviolet and soft X-ray bands. Substantial and observable luminosities may
be generated even for axion-photon couplings \ll 10^{-11} GeV^{-1}. We propose
that axion-photon conversion may explain the observed excess emission of soft
X-rays from galaxy clusters, and may also contribute to the diffuse unresolved
cosmic X-ray background. We list a number of correlated predictions of the
scenario.


title: Modeling the Resolved Disk Around the Class 0 Protostar L1527

abstract:
  We present high-resolution sub/millimeter interferometric imaging of the
Class 0 protostar L1527 IRS (IRAS 04368+2557) at 870 micron and 3.4 mm from the
Submillimeter Array (SMA) and Combined Array for Research in Millimeter
Astronomy (CARMA). We detect the signature of an edge-on disk surrounding the
protostar with an observed diameter of 180 AU in the sub/millimeter images. The
mass of the disk is estimated to be 0.007 M_sun, assuming optically thin,
isothermal dust emission. The millimeter spectral index is observed to be quite
shallow at all the spatial scales probed; alpha ~ 2, implying a dust opacity
spectral index beta ~ 0. We model the emission from the disk and surrounding
envelope using Monte Carlo radiative transfer codes, simultaneously fitting the
sub/millimeter visibility amplitudes, sub/millimeter images, resolved L\arcmin\
image, spectral energy distribution, and mid-infrared spectrum. The best
fitting model has a disk radius of R = 125 AU, is highly flared (H ~ R^1.3),
has a radial density profile rho ~ R^-2.5, and has a mass of 0.0075 M_sun. The
scale height at 100 AU is 48 AU, about a factor of two greater than vertical
hydrostatic equilibrium. The resolved millimeter observations indicate that
disks may grow rapidly throughout the Class 0 phase. The mass and radius of the
young disk around L1527 is comparable to disks around pre-main sequence stars;
however, the disk is considerably more vertically extended, possibly due to a
combination of lower protostellar mass, infall onto the disk upper layers, and
little settling of ~1 micron-sized dust grains.


title:
Many-body effects and possible superconductivity in the 2D metallic
  surface states of 3D topological insulators

abstract:
  We theoretically consider temperature and density-dependent electron-phonon
interaction induced many-body effects in the two-dimensional (2D) metallic
carriers confined on the surface of the 3D topological insulator (e.g.
Bi$_2$Se$_3$). We calculate the temperature and the carrier density dependence
of the real and imaginary parts of the electronic self-energy, the interacting
spectral function, and the phonon-induced velocity renormalization, enabling us
to obtain a simple density and temperature dependent effective dimensionless
electron-phonon coupling constant parameter, which increases (decreases)
strongly with increasing density (temperature). Our theoretical results can be
directly and quantitatively compared with experimental ARPES or STS studies of
the 2D spectral function of topological insulator surface carriers. In
particular, we predict the possible existence of surface superconductivity in
Bi$_2$Se$_3$ induced by strong electron-phonon interaction.


title:
Estimating the parameters of globular cluster M 30 (NGC 7099) from
  time-series photometry

abstract:
  We present the analysis of 26 nights of V and I time-series observations from
2011 and 2012 of the globular cluster M 30 (NGC 7099). We used our data to
search for variable stars in this cluster and refine the periods of known
variables; we then used our variable star light curves to derive values for the
cluster's parameters. We used difference image analysis to reduce our data to
obtain high-precision light curves of variable stars. We then estimated the
cluster parameters by performing a Fourier decomposition of the light curves of
RR Lyrae stars for which a good period estimate was possible. We also derive an
estimate for the age of the cluster by fitting theoretical isochrones to our
colour-magnitude diagram (CMD). Out of 13 stars previously catalogued as
variables, we find that only 4 are bona fide variables. We detect two new RR
Lyrae variables, and confirm two additional RR Lyrae candidates from the
literature. We also detect four other new variables, including an eclipsing
blue straggler system, and an SX Phoenicis star. This amounts to a total number
of confirmed variable stars in M 30 of 12. We perform Fourier decomposition of
the light curves of the RR Lyrae stars to derive cluster parameters using
empirical relations. We find a cluster metallicity [Fe/H]_ZW=-2.01 +- 0.04, or
[Fe/H]_UVES=-2.11 +- 0.06, and a distance of 8.32 +- 0.20 kpc (using RR0
variables), 8.10 kpc (using one RR1 variable), and 8.35 +- 0.42 kpc (using our
SX Phoenicis star detection in M 30). Fitting isochrones to the CMD, we
estimate an age of 13.0 +- 1.0 Gyr for M 30.


title: Double Handled Brane Tilings

abstract:
  We classify the first few brane tilings on a genus 2 Riemann surface and
identify their toric Calabi-Yau moduli spaces. These brane tilings are
extensions of tilings on the 2-torus, which represent one of the largest known
classes of 4d N=1 superconformal field theories for D3-branes. The
classification consists of 16 distinct genus 2 brane tilings with up to 8
quiver fields and 4 superpotential terms. The Higgs mechanism is used to relate
the different theories.


title: Multi-color detection of gravitational arcs

abstract:
  Strong gravitational lensing provides fundamental insights into the
understanding of the dark matter distribution in massive galaxies, galaxy
clusters and the background cosmology. Despite their importance, the number of
gravitational arcs discovered so far is small. The urge for more complete,
large samples and unbiased methods of selecting candidates is rising. A number
of methods for the automatic detection of arcs have been proposed in the
literature, but large amounts of spurious detections retrieved by these methods
forces observers to visually inspect thousands of candidates per square degree
in order to clean the samples. This approach is largely subjective and requires
a huge amount of eye-ball checking, especially considering the actual and
upcoming wide field surveys, which will cover thousands of square degrees. In
this paper we study the statistical properties of colours of gravitational arcs
detected in the 37 deg^2 of the CARS survey. We have found that most of them
lie in a relatively small region of the (g'-r',r'-i') colour-colour diagram. To
explain this property, we provide a model which includes the lensing optical
depth expected in a LCDM cosmology that, in combination with the sources'
redshift distribution of a given survey, in our case CARS, peaks for sources at
redshift z~1. By further modelling the colours derived from the SED of the
galaxies dominating the population at that redshift, the model well reproduces
the observed colours. By taking advantage of the colour selection suggested by
both data and model, we show that this multi-band filtering returns a sample
83% complete and a contamination reduced by a factor of ~6.5 with respect to
the single-band arcfinder sample. New arc candidates are also proposed.


title: Additivity relations in quantum correlations

abstract:
  Does the sum of correlations in subsystems constitute the correlation in the
total system? Such a concept can be expressed by an additivity relationship of
correlations. From a strong subadditivity condition of von Neumann entropy,
four different additivity relations in total correlation are derived and
quantified. Based upon the classification of the additivity in total
correlation, we identify the corresponding additive relationships in
entanglement. It is also discussed that similar relationships are satisfied for
quantum discord of pure states, but it is not always true for mixed states.


title:
Finding a 61.0-day orbital period for the HMXB 4U 1036-56 with the
  Swift-BAT monitoring

abstract:
  Since November 2004, the Burst Alert Telescope on board Swift is producing a
monitoring of the entire sky in the 15-150 keV band, recording the timing and
spectral behavior of the detected sources. Here we study the properties of the
HMXB 4U 1036-56 using both the BAT survey data and those from a Swift-XRT
observation. A folding analysis performed on the BAT light curve of the first
100 months of survey unveils a periodic modulation with a period of 61.0 days,
tied to the presence in the BAT light curve of several intensity enhancements
lasting ~1/4 of P_0. We explain this modulation as the orbital period of the
binary system. The position of 4U 1036-56 on the Corbet diagram, the derived
semi-major orbit axis (~ 180 R_sun), and the bulk of the source emission
observed in a limited portion of the orbit are consistent with a Be companion
star. The broad band 0.2-150 keV spectrum is well modeled with a flat absorbed
power law with a cut-off at ~16 keV. Finally, we explore the possible
association of 4U 1036-56 with the gamma-ray source AGL J1037-5808, finding
that the BAT light curve does not show any correlation with the gamma-ray
outburst observed in November 2012.


title:
Variable jet properties in GRB110721A: Time resolved observations of the
  jet photosphere

abstract:
  {\it Fermi Gamma-ray Space Telescope} observations of GRB110721A have
revealed two emission components from the relativistic jet: emission from the
photosphere, peaking at $\sim 100$ keV and a non-thermal component, which peaks
at $\sim 1000$ keV. We use the photospheric component to calculate the
properties of the relativistic outflow. We find a strong evolution in the flow
properties: the Lorentz factor decreases with time during the bursts from
$\Gamma \sim 1000$ to $\sim 150$ (assuming a redshift $z=2$; the values are
only weakly dependent on unknown efficiency parameters). Such a decrease is
contrary to the expectations from the internal shocks and the isolated magnetar
birth models. Moreover, the position of the flow nozzle measured from the
central engine, $r_0$, increases by more than two orders of magnitude. Assuming
a moderately magnetised outflow we estimate that $r_0$ varies from $10^6$ cm to
$\sim 10^9$ cm during the burst. We suggest that the maximal value reflects the
size of the progenitor core. Finally, we show that these jet properties
naturally explain the observed broken power-law decay of the temperature which
has been reported as a characteristic for GRB pulses.


title:
A compact theoretical model for opto-electronic devices based on quantum
  dot arrays

abstract:
  We present a theoretical model describing the photo-electrical response of a
system composed of quantum dots embedded in a dielectric matrix. The model is
based on the non-coherent rate equations and the Transfer Hamiltonian
formalism. The self charge was included. Within this methodology, the response
of the system only depends on fundamental material parameters and its geometry.
Transport through several quantum dot configurations was simulated obtaining
current-voltage curves in dark and illuminating conditions for three different
scenarios: single one quantum dot and two quantum dots in parallel and serial
configurations. Despite the simplicity of the model, it has been used to
reproduce successfully experimental results.


title:
Empirical Constraints on the Star Formation & Redshift Dependence of the
  Lyman Alpha `Effective' Escape Fraction

abstract:
  We derive empirical constraints on the volume averaged `effective' escape
fraction of Lyman Alpha (Lya) photons from star forming galaxies as a function
of redshift, by comparing star formation functions inferred directly from
observations, to observed Lya luminosity functions. Our analysis shows that the
effective escape fraction increases from f_esc^eff ~ 1-5 % at z=0, to f_esc^eff
~ 10 % at z=3-4, and to f_esc^eff=30-50 % at z=6. Our constraint at z=6 lies
above predictions by models that do not include winds, and therefore hints at
the importance of winds in the Lya transfer process (even) at this redshift. We
can reproduce Lya luminosity functions with an f_esc^eff that does not depend
on the galaxies star formation rates (SFR) over up to ~2 orders of magnitude in
Lya luminosity. It is possible to reproduce the luminosity functions with an
f_esc^eff that decreases with SFR - which appears favored by observations of
drop-out galaxies - in models which include a large scatter (~ 1.0 dex) in
f_esc^eff, and/or in which star forming galaxies only have a non-zero f_esc^eff
for a fraction of their life-time or a fraction of sightlines. We provide a
fitting formula that summarizes our findings.


title: The 54 days orbital period of AX J1820.5-1434 unveiled by Swift

abstract:
  The hard X-ray survey that Swift-BAT has been performing since late 2004 has
provided a considerable database for a large number of sources whose hard X-ray
emission was poorly known. We are exploiting the BAT survey archive to improve
the temporal and spectral characterization of the Galactic hard-X-ray sources.
In this letter we focus on the study of the high mass X-ray binary AX
J1820.5-1434. All the data relevant to AX J1820.5-1434 have been extracted from
the BAT survey archive and analyzed using a folding technique to search for
periodical modulations. A broad-band spectral analysis was also performed
complementing the BAT spectrum with the available Swift-XRT and XMM-Newton
pointed observations. A timing analysis has revealed the detection of a
coherent signal at P_0=54.0 +/- 0.4 days, that we interpret as the orbital
period of the binary system. When folded with a period of P_0, the light curve
shows an asymmetric profile, with a minimum roughly consistent with zero
intensity. The broad band spectral analysis performed coupling Swift-XRT,
XMM-Newton and Swift-BAT spectra is well modeled with an absorbed power law
with no evidence for an exponential cutoff.


title: What is the shape of the initial state?

abstract:
  We argue that a plausible operational definition for an initial state of the
Universe is the initial quantum state of the curvature perturbations generated
during inflation. We provide a parameterization of this state and generalize
the standard in-in formalism to incorporate the structures in this state into
the computation of correlators of the perturbations. Measurements of these
correlators using both the CMB as well as large scale structure probe different
structures in the initial state, as they give rise to bi- and tri-spectra
peaked on different shapes of triangles and quadrilaterals in momentum space.
In essence, the shapes implied by the correlators feed directly into
information about the shape of the initial state and what physics could have
preceded inflation to set this state up.


title: Modeling Information Propagation with Survival Theory

abstract:
  Networks provide a skeleton for the spread of contagions, like, information,
ideas, behaviors and diseases. Many times networks over which contagions
diffuse are unobserved and need to be inferred. Here we apply survival theory
to develop general additive and multiplicative risk models under which the
network inference problems can be solved efficiently by exploiting their
convexity. Our additive risk model generalizes several existing network
inference models. We show all these models are particular cases of our more
general model. Our multiplicative model allows for modeling scenarios in which
a node can either increase or decrease the risk of activation of another node,
in contrast with previous approaches, which consider only positive risk
increments. We evaluate the performance of our network inference algorithms on
large synthetic and real cascade datasets, and show that our models are able to
predict the length and duration of cascades in real data.


title:
Calibrating stellar population models with Magellanic Cloud star
  clusters

abstract:
  Stellar population models are commonly calculated using star clusters as
calibrators for those evolutionary stages that depend on free parameters.
However, discrepancies exist among different models, even if similar sets of
calibration clusters are used. With the aim of understanding these
discrepancies, and of improving the calibration procedure, we consider a set of
43 Magellanic Cloud (MC) clusters taking age and photometric information from
the literature. We carefully assign ages to each cluster based on up-to-date
determinations ensuring that these are as homogeneous as possible. To cope with
statistical fluctuations, we stack the clusters in five age bins deriving for
each of them integrated luminosities and colors. We find that clusters become
abruptly red in optical and optical-IR colors as they age from ~0.6 to 1 Gyr,
which we interpret as due to the development of a well-populated thermally
pulsing asymptotic giant branch (TP-AGB). We argue that other studies missed
this detection because of coarser age binnings. Maraston (2005; M05) and
Girardi et al. (2010) models predict the presence of a populated TP-AGB at ~0.6
Gyr, with a correspondingly very red integrated color, at variance with the
data; Bruzual & Charlot (2003) and Conroy et al. (2009) models run within the
error bars at all ages. The discrepancy between the synthetic colors of M05
models and the average colors of MC clusters results from the now obsolete age
scale adopted. Finally, our finding that the TP-AGB phase appears to develop
between ~0.6-1 Gyr is dependent on the adopted age scale for the clusters and
may have important implications for stellar evolution.


title: A Model for Tracking Fronts of Stress-Induced Permeability Enhancement

abstract:
  Using an analogy to the classical Stefan problem, we construct evolution
equations for the fluid pore pressure on both sides of a propagating
stress-induced damage front. Closed form expressions are derived for the
position of the damage front as a function of time for the cases of
thermally-induced damage as well as damage induced by over-pressure. We derive
expressions for the flow rate during constant pressure fluid injection from the
surface corresponding to a spherically shaped subsurface damage front. Finally,
our model results suggest an interpretation of field data obtained during
constant pressure fluid injection over the course of 16 days at an injection
site near Desert Peak, NV.


title: The Turbulence Power Spectrum in Optically Thick Interstellar Clouds

abstract:
  The Fourier power spectrum is one of the most widely used statistical tools
to analyze the nature of magnetohydrodynamic turbulence in the interstellar
medium. Lazarian & Pogosyan (2004) predicted that the spectral slope should
saturate to -3 for an optically thick medium and many observations exist in
support of their prediction. However, there have not been any numerical studies
to-date testing these results. We analyze the spatial power spectrum of MHD
simulations with a wide range of sonic and Alfv\'enic Mach numbers, which
include radiative transfer effects of the $^{13}$CO transition. We confirm
numerically the predictions of Lazarian & Pogosyan (2004) that the spectral
slope of line intensity maps of an optically thick medium saturates to -3.
Furthermore, for very optically thin supersonic CO gas, where the density or CO
abundance values are too low to excite emission in all but the densest shock
compressed gas, we find that the spectral slope is shallower than expected from
the column density. Finally, we find that mixed optically thin/thick CO gas,
which has average optical depths on order of unity, shows mixed behavior: for
super-Alfv\'enic turbulence, the integrated intensity power spectral slopes
generally follow the same trend with sonic Mach number as the true column
density power spectrum slopes. However, for sub-Alfv\'enic turbulence the
spectral slopes are steeper with values near -3 which are similar to the very
optically thick regime.


title: Superconductivity in the Cu(Ir1-xPtx)2Se4 Spinel

abstract:
  We report the observation of superconductivity in the CuIr2Se4 spinel induced
by partial substitution of Pt for Ir. The optimal doping level for
superconductivity in Cu(Ir1-xPtx)2Se4 is x = 0.2, where Tc is 1.76 K. A
superconducting Tc vs. composition dome is established between the metallic,
normal conductor CuIr2Se4 and semiconducting CuIrPtSe4. Electronic structure
calculations show that the optimal Tc occurs near the electron count of a large
peak in the calculated electronic density of states and that CuIrPtSe4 is a
band-filled insulator. Characterization of the superconducting state in this
heavy metal spinel through determination of {\Delta}C/{\gamma}Tc, indicates
that it is BCS-like. The relatively high upper critical field at the optimal
superconducting composition (Hc2(0) = 3.2 T) is much larger than that reported
for analogous rhodium spinels and is comparable to or exceeds the Pauli field
(mu0Hp), suggesting that strong spin orbit coupling may influence the
superconducting state. Further, comparison to doped CuIr2S4 suggests that
superconductivity in iridium spinels is not necessarily associated with the
destabilization of a charge-ordered spin-paired state through doping.


title: Statistical Inference and String Theory

abstract:
  In this note we expose some surprising connections between string theory and
statistical inference. We consider a large collective of agents sweeping out a
family of nearby statistical models for an M-dimensional manifold of
statistical fitting parameters. When the agents making nearby inferences align
along a d-dimensional grid, we find that the pooled probability that the
collective reaches a correct inference is the partition function of a
non-linear sigma model in d dimensions. Stability under perturbations to the
original inference scheme requires the agents of the collective to distribute
along two dimensions. Conformal invariance of the sigma model corresponds to
the condition of a stable inference scheme, directly leading to the Einstein
field equations for classical gravity. By summing over all possible
arrangements of the agents in the collective, we reach a string theory. We also
use this perspective to quantify how much an observer can hope to learn about
the internal geometry of a superstring compactification. Finally, we present
some brief speculative remarks on applications to the AdS/CFT correspondence
and Lorentzian signature spacetimes.


title:
X-ray view of four high-luminosity Swift/BAT AGN: Unveiling obscuration
  and reflection with Suzaku

abstract:
  The Swift/BAT nine-month survey observed 153 AGN, all with ultra-hard X-ray
BAT fluxes in excess of 10^-11 erg cm^-2 s^-1 and an average redshift of 0.03.
Among them, four of the most luminous BAT AGN (44.73 < Log L(BAT) < 45.31) were
selected as targets of Suzaku follow-up observations: J2246.0+3941 (3C 452),
J0407.4+0339 (3C 105), J0318.7+6828, and J0918.5+0425. The column density,
scattered/reflected emission, the properties of the Fe K line, and a possible
variability are fully analyzed. For the latter, the spectral properties from
Chandra, XMM-Newton and Swift/XRT public observations were compared with the
present Suzaku analysis. Of our sample, 3C 452 is the only certain
Compton-thick AGN candidate because of i) the high absorption and strong
Compton reflection; ii) the lack of variability; iii) the "buried" nature, i.e.
the low scattering fraction (<0.5%) and the extremely low relative [OIII]
luminosity. In contrast 3C 105 is not reflection-dominated, despite the
comparable column density, X-ray luminosity and radio morphology, but shows a
strong long-term variability in flux and scattering fraction, consistent with
the soft emission being scattered from a distant region (e.g., the narrow
emission line region). The sample presents high (>100) X-to-[OIII] luminosity
ratios, confirming the [OIII] luminosity to be affected by residual extinction
in presence of mild absorption, especially for "buried" AGN such as 3C 452.
Three of our targets are powerful FRII radio galaxies, making them the most
luminous and absorbed AGN of the BAT Seyfert survey despite the inversely
proportional N_H - L_X relation.