title:
BaFe2As2/Fe bilayers with [001]-tilt grain boundary on MgO and SrTiO3
  bicrystal substrates

abstract:
  Co-doped BaFe2As2 (Ba-122) can be realized on both MgO and SrTiO3 bicrystal
substrates with [001]-tilt grain boundary by employing Fe buffer layers.
However, an additional spinel (i.e. MgAl2O4) buffer between Fe and SrTiO3 is
necessary since an epitaxial, smooth surface of Fe layer can not be grown on
bare SrTiO3. Both types of bicrystal films show good crystalline quality.


title:
Effective Field Theory Analysis of New Physics in e+e- -> W+W- at a
  Linear Collider

abstract:
  We analyze new physics contributions to $e^+e^-\to W^+W^-$ at the TeV energy
scale, employing an effective field theory framework. A complete basis of
next-to-leading order operators in the standard model effective Lagrangian is
used, both for the nonlinear and the linear realization of the electroweak
sector. The elimination of redundant operators via equations-of-motion
constraints is discussed in detail. Polarized cross sections for $e^+e^-\to
W^+W^-$ (on-shell) are computed and the corrections to the standard model
results are given in an expansion for large $s/M^2_W$. The dominant relative
corrections grow with $s$ and can be fully expressed in terms of modified
gauge-fermion couplings. These corrections are interpreted in the context of
the Goldstone boson equivalence theorem. Explicit new physics models are
considered to illustrate the generation and the potential size of the
coefficients in the effective Lagrangian. Brief comments are made on the
production of $W^+W^-$ pairs at the LHC.


title: Near-optimal separators in string graphs

abstract:
  Let G be a string graph (an intersection graph of continuous arcs in the
plane) with m edges. Fox and Pach proved that G has a separator consisting of
O(m^{3/4}\sqrt{log m})$ vertices, and they conjectured that the bound of
O(\sqrt m) actually holds. We obtain separators with O(\sqrt m \log m)
vertices.


title: Resonant state selection in synthetic ferrimagnets

abstract:
  Resonant activation of a synthetic antiferromagnet (SAF) is known to result
in a dynamic running state, where the SAF's symmetric spin-flop pair
continuously rotates between the two antiparallel ground states of the system,
with the two magnetic moments in-phase in the so-called acoustical
spin-resonance mode. The symmetry of an ideal SAF does not allow, however, to
deterministically select a particular ground state using a resonant excitation.
In this work, we study asymmetric SAF's, or synthetic ferrimagnets (SFi), in
which the two magnetic particles are different in thickness or are biased
asymmetrically with an external field. We show how the magnetic phase space of
the system can be reversibly tuned, post-fabrication, between the antiferro-
and ferri-magnetic behavior by exploiting these two asymmetry parameters and
applying a uniform external field. We observe a splitting of the optical
spin-resonance for the two ground states of the SFi system, with a frequency
spacing that can be controlled by a quasistatic uniform external field. We
demonstrate how the tunable magnetic asymmetry in SFi allows to
deterministically select a particular ground state using the splitting of the
optical spin-resonance. These results offer a new way of controlling the
magnetic state of a spin-flop bilayer, currently used in such large scale
applications as magnetic memory.


title: Dynamic trajectory control of gliders

abstract:
  A new dynamic control algorithm in order to direct the trajectory of a glider
to a pre-assigned target point is proposed. The algorithms runs iteratively and
the approach to the target point is self-correcting. The algorithm is
applicable to any non-powered lift-enabled vehicle (glider) travelling in
planetary atmospheres. As a proof of concept, we have applied the new algorithm
to the command and control of the trajectory of the Space Shuttle during the
Terminal Area Energy Management (TAEM) phase.


title: Higher-order Bernoulli, Frobenius-Euler and Euler polynomials

abstract:
  In this paper, we give some interesting identities of higher-order Bernoulli,
Frobenius-Euler and Euler polynomials arising from umbral calculus. From our
method of this paper, we can derive many interesting identities of special
polynomials


title:
Bulk Stabilization, the Extra-Dimensional Higgs Portal and Missing
  Energy in Higgs Events

abstract:
  To solve the hierarchy problem, extra-dimensional models must explain why the
new dimensions stabilize to the right size, and the known mechanisms for doing
so require bulk scalars that couple to the branes. Because of these couplings
the energetics of dimensional stabilization competes with the energetics of the
Higgs vacuum, with potentially observable effects. These effects are
particularly strong for one or two extra dimensions because the bulk-Higgs
couplings can then be super-renormalizable or dimensionless. Experimental reach
for such extra-dimensional Higgs `portals' are stronger than for gravitational
couplings because they are less suppressed at low-energies. We compute how
Higgs-bulk coupling through such a portal with two extra dimensions back-reacts
onto properties of the Higgs boson. When the KK mass is smaller than the Higgs
mass, mixing with KK modes results in an invisible Higgs decay width,
missing-energy signals at high-energy colliders, and new mechanisms of energy
loss in stars and supernovae. Astrophysical bounds turn out to be complementary
to collider measurements, with observable LHC signals allowed by existing
constraints. We comment on the changes to the Higgs mass-coupling relationship
caused by Higgs-bulk mixing, and how the resulting modifications to the running
of Higgs couplings alter vacuum-stability and triviality bounds.


title:
Typical and large-deviation properties of minimum-energy paths on
  disordered hierarchical lattices

abstract:
  We perform numerical simulations to study the optimal path problem on
disordered hierarchical graphs with effective dimension d=2.32. Therein, edge
energies are drawn from a disorder distribution that allows for positive and
negative energies. This induces a behavior which is fundamentally different
from the case where all energies are positive, only. Upon changing the
subtleties of the distribution, the scaling of the minimum energy path length
exhibits a transition from self-affine to self-similar. We analyze the precise
scaling of the path length and the associated ground-state energy fluctuations
in the vincinity of the disorder critical point, using a decimation procedure
for huge graphs. Further, using an importance sampling procedure in the
disorder we compute the negative-energy tails of the ground-state energy
distribution up to 12 standard deviations away from its mean. We find that the
asymptotic behavior of the negative-energy tail is in agreement with a
Tracy-Widom distribution. Further, the characteristic scaling of the tail can
be related to the ground-state energy flucutations, similar as for the directed
polymer in a random medium.


title:
Pressure-Induced Unconventional Superconducting Phase in the Topological
  Insulator Bi2Se3

abstract:
  Simultaneous low-temperature electrical resistivity and Hall effect
measurements were performed on single-crystalline Bi2Se3 under applied
pressures up to 50 GPa. As a function of pressure, superconductivity is
observed to onset above 11 GPa with a transition temperature Tc and upper
critical field Hc2 that both increase with pressure up to 30 GPa, where they
reach maximum values of 7 K and 4 T, respectively. Upon further pressure
increase, Tc remains anomalously constant up to the highest achieved pressure.
Conversely, the carrier concentration increases continuously with pressure,
including a tenfold increase over the pressure range where Tc remains constant.
Together with a quasi-linear temperature dependence of Hc2 that exceeds the
orbital and Pauli limits, the anomalously stagnant pressure dependence of Tc
points to an unconventional pressure-induced pairing state in Bi2Se3 that is
unique among the superconducting topological insulators.


title: Tenfold reduction of Brownian noise in optical interferometry

abstract:
  Thermally induced fluctuations impose a fundamental limit on precision
measurement. In optical interferometry, the current bounds of stability and
sensitivity are dictated by the excess mechanical damping of the
high-reflectivity coatings that comprise the cavity end mirrors. Over the
preceding decade, the mechanical loss of these amorphous multilayer reflectors
has at best been reduced by a factor of two. Here we demonstrate a new paradigm
in optical coating technology based on direct-bonded monocrystalline
multilayers, which exhibit both intrinsically low mechanical loss and high
optical quality. Employing these "crystalline coatings" as end mirrors in a
Fabry-P\'erot cavity, we obtain a finesse of 150,000. More importantly, at room
temperature, we observe a thermally-limited noise floor consistent with a
tenfold reduction in mechanical damping when compared with the best dielectric
multilayers. These results pave the way for the next generation of
ultra-sensitive interferometers, as well as for new levels of laser stability.


title:
Breakup of a nucleus with two weakly bound neutrons on a proton target:
  Single-scattering approximation

abstract:
  Three- and four-cluster breakup reactions in the ${}^{16}$C-proton scattering
are studied using three-body core-neutron-neutron model for ${}^{16}$C.
Single-scattering approximation (SSA) of four-particle equations for transition
operators is used to calculate three- and four-cluster breakup amplitudes at
200 and 300 MeV/nucleon energy near proton-neutron ($pn$) quasi free scattering
(QFS) conditions. The differential cross section is sharply peaked at $pn$ QFS
point and decreases rapidly whenever kinematical conditions deviate from $pn$
QFS. The accuracy of the SSA for the three-cluster breakup is estimated from a
three-body model and is found to be as good as 6\% at higher reaction energies
in suitable angular regimes. Furthermore, under an additional approximation the
three-cluster breakup amplitude factorizes into the $pn$ transition operator
and the overlap integral of two- and three-particle bound states. That
approximation usually reduces the cross section, in some cases even up to 10\%.


title: Asymptotic arbitrage in the Heston model

abstract:
  In the context of the Heston model, we establish a precise link between the
set of equivalent martingale measures, the ergodicity of the underlying
variance process and the concept of asymptotic arbitrage proposed in
Kabanov-Kramkov and in Follmer-Schachermayer.


title:
Electromagnetic momentum and the energy-momentum tensor in a linear
  medium with magnetic and dielectric properties

abstract:
  In a continuum setting, the energy-momentum tensor embodies the relations
between conservation of energy, conservation of linear momentum, and
conservation of angular momentum. The well-defined total energy and the
well-defined total momentum in a thermodynamically closed system with complete
equations of motion are used to construct the total energy-momentum tensor for
a stationary simple linear material with both magnetic and dielectric
properties illuminated by a quasimonochromatic pulse of light through a
gradient-index antireflection coating. The perplexing issues surrounding the
Abraham and Minkowski momentums are bypassed by working entirely with
conservation principles, the total energy, and the total momentum. We derive
electromagnetic continuity equations and equations of motion for the
macroscopic fields based on the material four-divergence of the traceless,
symmetric total energy-momentum tensor. We identify contradictions between the
macroscopic Maxwell equations and the continuum form of the conservation
principles. We resolve the contradictions, which are the actual fundamental
issues underlying the Abraham-Minkowski controversy, by constructing a unified
version of continuum electrodynamics that is based on establishing consistency
between the three-dimensional Maxwell equations for macroscopic fields, the
electromagnetic continuity equations, the four-divergence of the total
energy-momentum tensor, and a four-dimensional tensor formulation of
electrodynamics for macroscopic fields in a simple linear medium.


title:
Analysis of the new INTEGRAL Earth observations to measure the cosmic
  X-ray background

abstract:
  A new series of Earth occultation observations has been started in 2012 to
refine the determination of the cosmic X-ray background by the INTEGRAL
mission. We show here that the new detector lightcurves in the 3 to 160 keV
range differ from the ones obtained in 2006. Instead of the expected modulation
induced by the passage of the Earth through the field of view of the JEM-X,
IBIS/ISGRI and SPI instruments, we record unrelated variability on shorter
timescales. We discuss the differences obtained with the datasets of 2006 and
2012 in view of the changes in pointing direction, spacecraft orbit and solar
cycle phase. We conclude that the Earth occultation signal in 2012 is likely
blended by radioactive decay resulting from the activation of the spacecraft
when crossing the proton radiation belt at perigee passage. The observed
variability, on the other hand, results most likely from the current solar
maximum. In addition to a variable particle environment from inhomogeneities of
the solar wind, we also find evidence for hard X-ray auroral emission. While
the former can be traced by SPI/ACS counts, the latter - by enhancing
unpredictably the Earth emission - is a major disturbance for measuring the
diffuse X-ray background through occultation by the Earth.


title: Accretion disc viscosity: what do warped discs tell us?

abstract:
  Standard, planar accretion discs operate through a dissipative mechanism,
usually thought to be turbulent, and often modelled as a viscosity. This acts
to take energy from the radial shear, enabling the flow of mass and angular
momentum in the radial direction. In a previous paper we discussed
observational evidence for the magnitude of this viscosity, and pointed out
discrepancies between these values and those obtained in numerical simulations.
In this paper we discuss the observational evidence for the magnitude of the
dissipative effects which act in non--planar discs, both to transfer and to
eliminate the non--planarity. Estimates based on the model by Ogilvie (1999),
which assumes a small--scale, isotropic viscosity, give alignment timescales
for fully ionized discs which are apparently too short by a factor of a few
compared with observations, although we emphasize that more detailed
computations as well as tighter observational constraints are required to
verify this conclusion. For discs with low temperature and conductivity, we
find that the timescales for disc alignment based on isotropic viscosity are
too short by around two orders of magnitude. This large discrepancy suggests
that our understanding of viscosity in quiescent discs is currently inadequate.


title: Bethe subalgebras in Hecke algebra and Gaudin models

abstract:
  The generating function for elements of the Bethe subalgebra of Hecke algebra
is constructed as Sklyanin's transfer-matrix operator for Hecke chain. We show
that in a special classical limit q -> 1 the Hamiltonians of the Gaudin model
can be derived from the transfer-matrix operator of Hecke chain. We consruct a
non-local analogue of the Gaudin Hamiltonians for the case of Hecke algebras.


title: The Existence of a Billiard Orbit in the Regular Hyperbolic Simplex

abstract:
  In this note we establish the existence of a (n+1)-periodic billiard
trajectory inside an n-dimensional regular simplex in the hyperbolic space,
which hits the interior of every facet exactly once.


title: Edge-reflection positivity and weighted graph homomorphisms

abstract:
  B. Szegedy [Edge coloring models and reflection positivity, {\sl Journal of
the American Mathematical Society} {\bf 20} (2007) 969--988] showed that the
number of homomorphisms into a weighted graph is equal to the partition
function of a complex edge-coloring model. Using some results in geometric
invariant theory, we characterize for which weighted graphs the edge-coloring
model can be taken to be real valued that is, we characterize for which
weighted graphs the number of homomorphisms into them are edge-reflection
positive. In particular, we determine explicitly for which simple graphs the
number of homomorphisms into them is equal to the partition function of a real
edge-coloring model. This answers a question posed by Szegedy.


title: Parameter Estimation For Multivariate Generalized Gaussian Distributions

abstract:
  Due to its heavy-tailed and fully parametric form, the multivariate
generalized Gaussian distribution (MGGD) has been receiving much attention for
modeling extreme events in signal and image processing applications.
Considering the estimation issue of the MGGD parameters, the main contribution
of this paper is to prove that the maximum likelihood estimator (MLE) of the
scatter matrix exists and is unique up to a scalar factor, for a given shape
parameter \beta\in(0,1). Moreover, an estimation algorithm based on a
Newton-Raphson recursion is proposed for computing the MLE of MGGD parameters.
Various experiments conducted on synthetic and real data are presented to
illustrate the theoretical derivations in terms of number of iterations and
number of samples for different values of the shape parameter. The main
conclusion of this work is that the parameters of MGGDs can be estimated using
the maximum likelihood principle with good performance.


title: An eigenvector based approach to neutrino mixing

abstract:
  We propose a model-independent analysis of the neutrino mass matrix through
an expansion in terms of the eigenvectors defining the lepton mixing matrix,
which we show can be parametrized as small perturbations of the tribimaximal
mixing eigenvectors. This approach proves to be powerful and convenient for
some aspects of lepton mixing, in particular when studying the sensitivity of
the mass matrix elements to departures from their tribimaximal form. In terms
of the eigenvector decomposition, the neutrino mass matrix can be understood as
originating from a tribimaximal dominant structure with small departures
determined by data. By implementing this approach to cases when the neutrino
masses originate from different mechanisms, we show that the experimentally
observed structure arises very naturally. We thus claim that the observed
deviations from the tribimaximal mixing pattern might be interpreted as a
possible hint of a ``hybrid'' nature of the neutrino mass matrix.


title: The VC-Dimension of Graphs with Respect to k-Connected Subgraphs

abstract:
  We study the VC-dimension of the set system on the vertex set of some graph
which is induced by the family of its $k$-connected subgraphs. In particular,
we give tight upper and lower bounds for the VC-dimension. Moreover, we show
that computing the VC-dimension is $\mathsf{NP}$-complete and that it remains
$\mathsf{NP}$-complete for split graphs and for some subclasses of planar
bipartite graphs in the cases $k = 1$ and $k = 2$. On the positive side, we
observe it can be decided in linear time for graphs of bounded clique-width.


title: Limit theorems for orthogonal polynomials related to circular ensembles

abstract:
  For a natural extension of the circular unitary ensemble of order n, we study
as n tends to infinity, the asymptotic behavior of the sequence of orthogonal
polynomials with respect to the spectral measure. The last term of this
sequence is the characteristic polynomial. After taking logarithm and
rescaling, we obtain a process indexed by t in [0,1]. We show that it converges
to a deterministic limit, and we describe the fluctuations and the large
deviations.


title:
Fast and Quasideterministic Single Ion Source from a Dipole-Blockaded
  Atomic Ensemble

abstract:
  We present a fast and Quasideterministic protocol for the production of
single ions and electrons from a cloud of laser cooled atoms. The approach is
based on a two-step process where first a single Rydberg atom is photo-excited
from a dipole-blockade configuration and subsequently ionized by an electric
field pulse. We theoretically describe these excitation-ionization cycles via
dynamical quantum maps and observe a rich behavior of the ionization dynamics
as a function of laser Rabi frequency, pulse duration and particle number. Our
results show that a fast sequential heralded production of single charged
particles is achievable even from an unstructured and fluctuating atomic
ensemble.


title:
Fully Coupled Electromechanical Elastodynamic Model for Guided Wave
  Propagation Analysis

abstract:
  Physics-based computational models play a key role in the study of wave
propagation for structural health monitoring (SHM) and the development of
improved damage detection methodologies. Due to the complex nature of guided
waves, accurate and efficient computation tools are necessary to investigate
the mechanisms responsible for dispersion, coupling, and interaction with
damage. In this paper, a fully coupled electromechanical elastodynamic model
for wave propagation in a heterogeneous, anisotropic material system is
developed. The final framework provides the full three dimensional displacement
and electrical potential fields for arbitrary plate and transducer geometries
and excitation waveform and frequency. The model is validated theoretically and
proven computationally efficient. Studies are performed with surface bonded
piezoelectric sensors to gain insight into the physics of experimental
techniques used for SHM. Collocated actuation of the fundamental Lamb wave
modes is modeled over a range of frequencies to demonstrate mode tuning
capabilities. The displacement of the sensing surface is compared to the
piezoelectric sensor electric potential to investigate the relationship between
plate displacement and sensor voltage output. Since many studies, including the
ones investigated in this paper, are difficult to perform experimentally, the
developed model provides a valuable tool for the improvement of SHM techniques.


title:
Probing Jet Conditions with Multi-frequency, Centimeter-band Linear
  Polarization: PKS 0420-01

abstract:
  We have used single-dish centimeter-band, multi-frequency linear polarization
and total flux density monitoring observations obtained by UMRAO at 14.5, 8,
and 4.8 GHz during gamma-ray flaring to constrain propagating shock-in-jet
models; this procedure allows us to probe jet conditions at or near the
presumed parsec-scale gamma-ray emission site within the relativistic jet.
Results are presented for the blazar 0420-014 during the gamma-ray flare
detected by the LAT which peaked in late January 2010. Our work identifies the
passage of three forward-moving transverse shocks during the radio-band
flaring, a shock Lorentz factor of 12, and an observer's viewing angle of 2
degrees and sets limits on the energy distribution of the radiating particles.


title: Triplet Higgs boson collider phenomenology after the LHC

abstract:
  ATLAS and CMS have discovered a Standard Model Higgs-like particle. One of
the main discovery channels is the Higgs decay to two photons, which, at the
moment, seems to be considerably enhanced over the Standard Model expectation.
Models with additional charged matter coupling to the Higgs sector can enhance
or decrease the Higgs to two photons branching ratio. We take this as
motivation to confront the so-called Georgi-Machacek model of Higgs triplets
with the results of recent searches for a SM Higgs boson performed at the LHC.
We also investigate the model in regions of the allowed parameter space
relevant for a SM-like phenomenology. The Georgi-Machacek model avoids
tree-level issues of the T parameter, while offering a vastly modified Higgs
phenomenology compared to the Standard Model. This comes at the price of
introducing another fine-tuning problem related to electroweak precision
measurements. We investigate the collider phenomenology of the Georgi-Machacek
model in the light of existing collider constraints beyond any effective field
theory approximation and contextualize our findings with electroweak precision
constraints.


title: Toward a theory of curvature-scaling gravity

abstract:
  A salient feature of Horava gravity is the anisotropic time variable. We
propose an alternative construction of the spacetime manifold which naturally
enables time anisotropy. We promote the role of curvature: the Ricci scalar R
at a given point sets the length scales for physical processes - including
gravity - in the local inertial frames enclosing that point. The manifold is a
patchwork of local regions; each region is Lorentz invariant and adopts a local
scale a_R defined as a_R = 1/sqrt|R|. In each local patch, the length scales of
physical processes are measured relatively to a_R, and only their dimensionless
ratios partake in the dynamics of physical processes. Time anisotropy arises by
requiring that the form - but not necessarily the parameters - of physical laws
be unchanged under variations of the local a_R as one moves on the manifold.
The time scaling is found to be dt ~ a_R^(3/2) whereas the spatial part scales
as dx ~ a_R.
  We show how to conjoin the local patches of the manifold in a way which
respects causality and special relativity, as well as the equivalence and
general covariance principles. All of Einstein's insights are preserved but the
parameters of physical laws are only valid locally and become functions of the
prevailing Ricci scalar. This alternative construction of the manifold permits
a unique choice for the Lagrangian of gravity coupled with matter. Curvature is
actively involved in the dynamics of physical processes by setting the scale
for them.
  In vacuo our theory takes the form of R^2 gravity and adopts a larger set of
solutions superseding those of Einstein-Hilbert action R. We provide two
solutions: one solution connects our work to Mannheim's theory of galactic
rotation curves; the other leads to novel properties for Schwarzschild black
holes. We apply the theory to address problems in cosmology and discuss its
implications in quantum gravity.


title:
Compactified rotating branes in the matrix model, and excitation
  spectrum towards one loop

abstract:
  We study compactified brane solutions of type R^4 x K in the IIB matrix
model, and obtain explicitly the bosonic and fermionic fluctuation spectrum
required to compute the one-loop effective action. We verify that the one-loop
contributions are UV finite for R^4 x T^2, and supersymmetric for R^3 x S^1.
The higher Kaluza-Klein modes are shown to have a gap in the presence of flux
on T^2, and potential problems concerning stability are discussed.


title:
Studies of W boson plus jets production in p\bar{p} collisions at
  sqrt(s)=1.96 TeV

abstract:
  We present a comprehensive analysis of inclusive W(\to e\nu)+n-jet (n\geq
1,2,3,4) production in proton-antiproton collisions at a center-of-mass energy
of 1.96 TeV at the Tevatron collider using a 3.7 fb^{-1} dataset collected by
the D0 detector. Differential cross sections are presented as a function of the
jet rapidities (y), lepton transverse momentum (p_T) and pseudorapidity (\eta),
the scalar sum of the transverse energies of the W boson and all jets (H_T),
leading dijet p_T and invariant mass, dijet rapidity separations for a variety
of jet pairings for p_T-ordered and angular-ordered jets, dijet opening angle,
dijet azimuthal angular separations for p_T-ordered and angular-ordered jets,
and W boson transverse momentum. The mean number of jets in an event containing
a W boson is measured as a function of H_T, and as a function of the rapidity
separations between the two highest-p_T jets and between the most widely
separated jets in rapidity. Finally, the probability for third-jet emission in
events containing a W boson and at least two jets is studied by measuring the
fraction of events in the inclusive W+2-jet sample that contain a third jet
over a p_T threshold. The analysis employs a regularized singular value
decomposition technique to accurately correct for detector effects and for the
presence of backgrounds. The corrected data are compared to particle level
next-to-leading order perturbative QCD predictions, predictions from all-order
resummation approaches, and a variety of leading-order and matrix-element plus
parton-shower event generators. Regions of the phase space where there is
agreement or disagreement with the data are discussed for the different models
tested.


title:
Noise Intensity-Intensity Correlations and the Fourth Cumulant of
  Current Fluctuations

abstract:
  We report measurements of the correlation between intensities of noise at
different frequencies on a tunnel junction under ac excitation, which
corresponds to two-mode intensity correlations in optics. We observe positive
correlation, \emph{i.e.} photon bunching, which exist only for certain
relations between the excitation frequency and the two detection frequencies,
depending on the dc bias of the sample. We demonstrate that these correlations
are proportional to the fourth cumulant of current fluctuations.


title: Chiral Superfluidity for the Heavy Ion Collisions

abstract:
  We argue that the strongly coupled quark-gluon plasma formed at LHC and RHIC
can be considered as a chiral superfluid. The "normal" component of the fluid
is the thermalized matter in common sense, while the "superfluid" part consists
of long wavelength (chiral) fermionic states moving independently. We use the
bosonization procedure with a finite cut-off and obtain a dynamical axion-like
field out of the chiral fermionic modes. Then we use relativistic hydrodynamics
for macroscopic description of the effective theory obtained after the
bosonization. Finally, solving the hydrodynamic equations in gradient
expansion, we find that in the presence of external electromagnetic fields the
motion of the "superfluid" component gives rise to the chiral magnetic, chiral
electric and dipole wave effects. Latter two effects are specific for a
two-component fluid, which provides us with crucial experimental tests of the
model. By considering probe quarks one can show that the fermionic spectrum at
the intermediate temperatures (T_c < T < 2 T_c) has a gap between near-zero
modes and the bulk of the spectrum - one more hint supporting the two-component
model.


title: A perturbation theory for the Anderson model

abstract:
  Within the diagrammatic real time approach \cite{K\"onig96, Schoeller97}, the
current across a quantum dot which is tunnel coupled to two leads at different
chemical potentials is calculated by the use of two objects referred to as
kernels. The stationary reduced density matrix of the quantum dot is determined
by the use of the density matrix kernel, while the current kernel is used in a
second step to determine the stationary current across the dot. If the
tunneling Hamiltonian is multiplied by a coupling parameter ``w``, then
everything, including the kernels, the stationary density matrix as well as the
stationary current, can be viewed as a function of w. In the time space, and at
every single and fixed time t, the kernels have the clear structure of a
convergent power series in w. Refer to the coefficients of these power series
as the orders of the kernels. It is intuitive to truncate the kernels at some
finite order and to perform remaining calculations by the use of the
corresponding approximate kernels. However, the quantities which actually
appear in the calculations are not the kernels as a function of time but rather
their Laplace transforms, and here only in the limit \lambda \to 0. The
statement that even in this limit the structure of a convergent power series in
the coupling parameter is still conserved is shown in the text. The statement
that the stationary density matrix and current are still analytic in the
coupling parameter is shown, assuming the quantum dot is the single impurity
Anderson model (SIAM). Finally, results for the kernels up to sixth order,
neglecting the doubly occupied state and assuming equal energies E_\uparrow=
E_\downarrow, are presented and discussed. In case the degenerate level lies
below the Fermi level, a zero bias resonance, getting more and more pronounced
with decreasing temperature, is expected.


title:
From the artificial atom to the Kondo-Anderson model: orientation
  dependent magneto-photoluminescence of charged excitons in InAs quantum dots

abstract:
  We present a magneto-photoluminescence study on neutral and charged excitons
confined to InAs/GaAs quantum dots. Our investigation relies on a confocal
microscope that allows arbitrary tuning of the angle between the applied
magnetic field and the sample growth axis. First, from experiments on neutral
excitons and trions, we extract the in-plane and on-axis components of the
Land\'e tensor for electrons and holes in the s-shell. Then, based on the
doubly negatively charged exciton magneto-photoluminescence we show that the
p-electron wave function spreads significantly into the GaAs barriers. We also
demonstrate that the p-electron g-factor depends on the presence of a hole in
the s-shell. The magnetic field dependence of triply negatively charged
excitons photoluminescence exhibits several anticrossings, as a result of
coupling between the quantum dot electronic states and the wetting layer.
Finally, we discuss how the system evolves from a Kondo-Anderson exciton
description to the artificial atom model when the orientation of the magnetic
field goes from Faraday to Voigt geometry.


title:
Ground states of the 2D sticky disc model: fine properties and $N^{3/4}$
  law for the deviation from the asymptotic Wulff shape

abstract:
  We investigate ground state configurations for a general finite number $N$ of
particles of the Heitmann-Radin sticky disc pair potential model in two
dimensions. Exact energy minimizers are shown to exhibit large microscopic
fluctuations about the asymptotic Wulff shape which is a regular hexagon: There
are arbitrarily large $N$ with ground state configurations deviating from the
nearest regular hexagon by a number of $\sim N^{3/4}$ particles. We also prove
that for any $N$ and any ground state configuration this deviation is bounded
above by $\sim N^{3/4}$. As a consequence we obtain an exact scaling law for
the fluctuations about the asymptotic Wulff shape. In particular, our results
give a sharp rate of convergence to the limiting Wulff shape.


title:
Bisimulation and p-morphism for branching-time logics with
  indistinguishability relations

abstract:
  In Zanardo, 1998, the Peircean semantics for branching-time logics is
enriched with a notion of indistinguishability at a moment t between histories
passing through t. Trees with indistinguishability relations provide a
semantics for a temporal language with tense and modal operators. In this paper
a notion of p-morphism and a notion of bisimulation, wrt this language and
semantics, are given and a number of preservation results are proven.


title: Hybrid Crossbar Architecture for a Memristor Based Memory

abstract:
  This paper describes a new memristor crossbar architecture that is proposed
for use in a high density cache design. This design has less than 10% of the
write energy consumption than a simple memristor crossbar. Also, it has up to 4
times the bit density of an STT-MRAM system and up to 11 times the bit density
of an SRAM architecture. The proposed architecture is analyzed using a detailed
SPICE analysis that accounts for the resistance of the wires in the memristor
structure. Additionally, the memristor model used in this work has been matched
to specific device characterization data to provide accurate results in terms
of energy, area, and timing.


title:
First Search for Dark Matter Annihilation in the Sun Using the ANTARES
  Neutrino Telescope

abstract:
  A search for high-energy neutrinos coming from the direction of the Sun has
been performed using the data recorded by the ANTARES neutrino telescope during
2007 and 2008. The neutrino selection criteria have been chosen to maximize the
selection of possible signals produced by the self-annihilation of weakly
interacting massive particles accumulated in the centre of the Sun with respect
to the atmospheric background. After data unblinding, the number of neutrinos
observed towards the Sun was found to be compatible with background
expectations. The $90\%$ CL upper limits in terms of spin-dependent and
spin-independent WIMP-proton cross-sections are derived and compared to
predictions of two supersymmetric models, CMSSM and MSSM-7. The ANTARES limits
are competitive with those obtained by other neutrino observatories and are
more stringent than those obtained by direct search experiments for the
spin-dependent WIMP-proton cross-section.


title: Extremal subgraphs of the $d$-dimensional grid graph

abstract:
  For each natural number $n$ we determine, both asymptotically and exactly,
the maximum number of edges an induced subgraph of order $n$ of the
$d$-dimension a grid graph ${\ints}^d$ can have. The asymptotic bound is
obtained by using a theorem Bollob\'{a}s and Thomason, and the exact bound is
obtained by induction. This generalizes some earlier results for the case $d=2$
on one hand, and for $n\leq 2^d$ on the other.


title: Oscillatory athermal quasi-static deformation of a model glass

abstract:
  We report computer simulations of oscillatory athermal quasi-static shear
deformation of dense amorphous samples of a three dimensional model glass
former. A dynamical transition is observed as the amplitude of the deformation
is varied: for large values of the amplitude the system exhibits diffusive
behavior and loss of memory of the initial conditions, whereas localization is
observed for small amplitudes. Our results suggest that the same kind of
transition found in driven colloidal systems is present in the case of
amorphous solids (e.g. metallic glasses). The onset of the transition is shown
to be related to the onset of energy dissipation. Shear banding is observed for
large system sizes, without, however, affecting qualitative aspects of the
transition.


title: Optical identification of crystal defects in CCD matrix

abstract:
  An original idea of semiconductor defects identification in CCD matrix was
presented in the article. The procedure is simple and easy to execute because
of no need for special and expensive equipment. The method classifies defects
into two groups: the point defects and the spatial defects (dislocations).
During the experiments it was proven that the type of defect affects the
behaviour of the dark current generation during the light gathering .


title: Discovery of an isolated compact elliptical galaxy in the field

abstract:
  We present the discovery of an isolated compact elliptical (cE) galaxy, found
during a search of SDSS DR7 for cEs, and for which we obtained WHT/ACAM
imaging. It is ~900 kpc distant from its nearest neighbour, has an effective
r-band radius of ~500 pc and a B-band mean surface brightness within its
effective radius of 19.75 mag/arcsec. Serendipitous deep SuprimeCam imaging
shows that there is no underlying disk. Its isolated position suggests that
there is an alternative channel to the stripping scenario for the formation of
compact ellipticals. We also report analysis of recent deeper imaging of the
previous candidate free-flying cE, which shows that it is, in fact, a normal
dwarf elliptical (dE). Hence the new cE reported here is the first confirmed
isolated compact elliptical to be found in the field.


title:
Imperfect and Unmatched CSIT is Still Useful for the Frequency
  Correlated MISO Broadcast Channel

abstract:
  Since Maddah-Ali and Tse showed that the completely stale transmitter-side
channel state information (CSIT) still benefits the Degrees of Freedom (DoF) of
the Multiple-Input-Multiple-Output (MISO) Broadcast Channel (BC), there has
been much interest in the academic literature to investigate the impact of
imperfect CSIT on \emph{DoF} region of time correlated broadcast channel. Even
though the research focus has been on time correlated channels so far, a
similar but different problem concerns the frequency correlated channels.
Indeed, the imperfect CSIT also impacts the DoF region of frequency correlated
channels, as exemplified by current multi-carrier wireless systems.
  This contribution, for the first time in the literature, investigates a
general frequency correlated setting where a two-antenna transmitter has
imperfect knowledge of CSI of two single-antenna users on two adjacent
subbands. A new scheme is derived as an integration of Zero-Forcing Beamforming
(ZFBF) and the scheme proposed by Maddah-Ali and Tse. The achievable DoF region
resulted by this scheme is expressed as a function of the qualities of CSIT.


title: Versatile scanning tunneling microscopy with 120ps time resolution

abstract:
  We describe a fully ultra-high vacuum compatible scanning tunneling
microscope (STM) optimized for radio-frequency signals. It includes in-situ
exchangeable tips adapted to high frequency cabling and a standard sample
holder, which offer access to the whole range of samples typically investigated
by STM. We demonstrate a time resolution of 120 ps using the nonlinear
I(V)-characteristic of the surface of highly oriented pyrolithic graphite. We
provide atomically resolved images in pulse mode related to a spatially varying
nonlinearity of the local density of states of the sample, thus, demonstrating
the possible spatial resolution of the instrument in pulse mode. Analysis of
the noise reveals that changes in the tunneling junction of 50 pA are
dynamically detectable at 120 ps time resolution.


title:
Sparse Frequency Analysis with Sparse-Derivative Instantaneous Amplitude
  and Phase Functions

abstract:
  This paper addresses the problem of expressing a signal as a sum of frequency
components (sinusoids) wherein each sinusoid may exhibit abrupt changes in its
amplitude and/or phase. The Fourier transform of a narrow-band signal, with a
discontinuous amplitude and/or phase function, exhibits spectral and temporal
spreading. The proposed method aims to avoid such spreading by explicitly
modeling the signal of interest as a sum of sinusoids with time-varying
amplitudes. So as to accommodate abrupt changes, it is further assumed that the
amplitude/phase functions are approximately piecewise constant (i.e., their
time-derivatives are sparse). The proposed method is based on a convex
variational (optimization) approach wherein the total variation (TV) of the
amplitude functions are regularized subject to a perfect (or approximate)
reconstruction constraint. A computationally efficient algorithm is derived
based on convex optimization techniques. The proposed technique can be used to
perform band-pass filtering that is relatively insensitive to narrow-band
amplitude/phase jumps present in data, which normally pose a challenge (due to
transients, leakage, etc.). The method is illustrated using both synthetic
signals and human EEG data for the purpose of band-pass filtering and the
estimation of phase synchrony indexes.


title: Exact Rosenthal-type inequalities for p=3, and related results

abstract:
  An exact Rosenthal-type inequality for the third absolute moments is given,
as well as a number of related results. Such results are useful in applications
to Berry--Esseen bounds.


title:
The LYRA Instrument Onboard PROBA2: Description and In-Flight
  Performance

abstract:
  The Large Yield Radiometer (LYRA) is an XUV-EUV-MUV (soft X-ray to
mid-ultraviolet) solar radiometer onboard the European Space Agency PROBA2
mission that was launched in November 2009. LYRA acquires solar irradiance
measurements at a high cadence (nominally 20 Hz) in four broad spectral
channels, from soft X-ray to MUV, that have been chosen for their relevance to
solar physics, space weather and aeronomy. In this article, we briefly review
the design of the instrument, give an overview of the data products distributed
through the instrument website, and describe the way that data are calibrated.
We also briefly present a summary of the main fields of research currently
under investigation by the LYRA consortium.


title: Moduli Operad over F1

abstract:
  In this paper we answer a question raised in [25], Sec. 4, by showing that
the genus zero moduli operad $\{\bar{M}_{0,n+1}\}$ can be endowed with natural
descent data that allow it to be considered as the lift to ${\rm Spec}\,\Z$ of
an operad over $\F_1$. The relevant descent data are based on a notion of
constructible sets and constructible functions over $\F_1$, which describes
suitable differences of torifications with a positivity condition on the class
in the Grothendieck ring. More generally, we do the same for the operads
$\{T_{d,n+1}\}$ (whose components were) introduced in [5]. Finally, we describe
a blueprint structure on $\{\bar{M}_{0,n}\}$ and we discuss from this
perspective the genus zero boundary modular operad $\{\bar{M}_{g,n+1}^0\}$.


title:
Can the Chameleon mechanism explain cosmic acceleration while satisfying
  Solar System constraints ?

abstract:
  The chameleon mechanism appearing in massive tensor-scalar theory of gravity
can effectively reduce the nonminimal coupling between the scalar field and
matter. This mechanism is invoked to reconcile cosmological data requiring
introduction of Dark Energy with small-scale stringent constraints on General
Relativity. In this communication, we present constraints on this mechanism
obtained by a cosmological analysis (based on Supernovae Ia data) and by a
Solar System analysis (based on PPN formalism).


title:
Entropy-based disciplinarity indicator: role taxonomy of journals in
  scientific communication systems and isolation degree. Knowledge
  importation/exportation profiles from journals and disciplines

abstract:
  In this research, a new indicator of disciplinarity-multidisciplinarity is
developed, discussed and applied. EBDI is based on the combination of the
frequency distribution of subject categories of journals citing or cited by the
analysis unit and the spread and diversity of the citations among subject
categories measured with Shannon-Wiener entropy. Its reproducibility,
robustness and consistence are discussed. Four of the combinations of its
values when applied to the cited and citing dimensions lead to a suggested
taxonomy of the role that the studied unit might have in terms of the
transformation of knowledge from different disciplines in the scientific
communication system and its position respect a hypothetical thematic core of
the discipline in which it has been classified. The indicator is applied to the
journals belonging to the first quartile of JCR-SSCI 2011 Library and
Information Science and an indicator-based taxonomy is applied and discussed,
pointing to differential thematic roles of the journals analyzed.


title:
Heat kernel estimates for pseudodifferential operators, fractional
  Laplacians and Dirichlet-to-Neumann operators

abstract:
  The purpose of this article is to establish upper and lower estimates for the
integral kernel of the semigroup exp(-tP) associated to a classical, strongly
elliptic pseudodifferential operator P of positive order on a closed manifold.
The Poissonian bounds generalize those obtained for perturbations of fractional
powers of the Laplacian. In the selfadjoint case, extensions to t in C_+ are
studied. In particular, our results apply to the Dirichlet-to-Neumann
semigroup.


title:
Systematics of dynamical mass ejection, nucleosynthesis, and
  radioactively powered electromagnetic signals from neutron-star mergers

abstract:
  We investigate systematically the dynamical mass ejection, r-process
nucleosynthesis, and properties of electromagnetic counterparts of neutron-star
(NS) mergers in dependence on the uncertain properties of the nuclear equation
of state (EoS) by employing 40 representative, microphysical high-density EoSs
in relativistic, hydrodynamical simulations. The crucial parameter determining
the ejecta mass is the radius R_1.35 of a 1.35 M_sun NS. NSs with smaller
R_1.35 ("soft" EoS) eject systematically higher masses. These range from ~10^-3
M_sun to ~10^-2 M_sun for 1.35-1.35 M_sun binaries and from ~5*10^-3 M_sun to
~2*10^-2 M_sun for 1.2-1.5 M_sun systems (with kinetic energies between
~5*10^49 erg and 10^51 erg). Correspondingly, the bolometric peak luminosities
of the optical transients of symmetric (asymmetric) mergers vary between
3*10^41 erg/s and 14*10^41 erg/s (9*10^41 erg/s and 14.5*10^41 erg/s) on
timescales between ~2 h and ~12 h. If these signals with absolute bolometric
magnitudes from -15.0 to -16.7 are measured, the tight correlation of their
properties with those of the merging NSs might provide valuable constraints on
the high-density EoS. The r-process nucleosynthesis exhibits a remarkable
robustness independent of the EoS, producing a nearly solar abundance pattern
above mass number 130. By the r-process content of the Galaxy and the average
production per event the Galactic merger rate is limited to 4*10^-5/yr
(4*10^-4/yr) for a soft (stiff) NS EoS, if NS mergers are the main source of
heavy r-nuclei. The production ratio of radioactive 232Th to 238U attains a
stable value of 1.64-1.67, which does not exclude NS mergers as potential
sources of heavy r-material in the most metal-poor stars.


title:
On the action of symplectic automorphisms on the $CH_0$-groups of some
  hyper-K\"ahler fourfolds

abstract:
  We prove that for any polarized symplectic automorphism of the Fano variety
of lines of a cubic fourfold (equipped with the Pl\"ucker polarization), the
induced action on the Chow group of 0-cycles is identity, as predicted by
Bloch-Beilinson conjecture.


title: Supergravity dual of c-extremization

abstract:
  Recently a general principle, called c-extremization, which determines the
exact R-symmetry of two-dimensional SCFTs with N = (0,2) supersymmetry was
identified. In this note we show that the supergravity dual corresponds to the
extremization of the T-tensor of N = 2 gauged supergravity in three-dimensions.
To support this claim, we demonstrate that the expected central charge of SCFTs
arising from twisted compactifications of four-dimensional N = 4 SYM on Riemann
surfaces, whose gravity dual is a reduction of five-dimensional U(1)^3 gauged
supergravity, is recovered in the three-dimensional framework.


title:
Self-Organization Promotes the Evolution of Cooperation with Cultural
  Propagation

abstract:
  In this paper three computational models for the study of the evolution of
cooperation under cultural propagation are studied: Kin Selection, Direct
Reciprocity and Indirect Reciprocity. Two analyzes are reported, one comparing
their behavior between them and a second one identifying the impact that
different parameters have in the model dynamics. The results of these analyzes
illustrate how game transitions may occur depending of some parameters within
the models and also explain how agents adapt to these transitions by
individually choosing their attachment to a cooperative attitude. These
parameters regulate how cooperation can self-organize under different
circumstances. The emergence of the evolution of cooperation as a result of the
agent's adapting processes is also discussed.


title: On algebraic structures of the Hochschild complex

abstract:
  We first review various known algebraic structures on the Hochschild
(co)homology of a differential graded algebras under weak Poincar{\'e} duality
hypothesis, such as Calabi-Yau algebras, derived Poincar{\'e} duality algebras
and closed Frobenius algebras. This includes a BV-algebra structure on
$HH^*(A,A^\vee)$ or $HH^*(A,A)$, which in the latter case is an extension of
the natural Gerstenhaber structure on $HH^*(A,A)$. As an example, after proving
that the chain complex of the Moore loop space of a manifold $M$ is a
CY-algebra and using Burghelea-Fiedorowicz-Goodwillie theorem we obtain a
BV-structure on the homology of the free space. In Sections 6 we prove that
these BV/coBVstructures can be indeed defined for the Hochschild homology of a
symmetric open Frobenius DG-algebras. In particular we prove that the
Hochschild homology and cohomology of a symmetric open Frobenius algebra is a
BV and coBV-algebra. In Section 7 we exhibit a BV structure on the shifted
relative Hochschild homology of a symmetric commutative Frobenius algebra. The
existence of a BV-structure on the relative Hochschild homology was expected in
the light of Chas-Sullivan and Goresky-Hingston results for free loop spaces.
In Section 8 we present an action of Sullivan diagrams on the Hochschild
(co)chain complex of a closed Frobenius DG-algebra. This recovers
Tradler-Zeinalian \cite{TZ} result for closed Froebenius algebras using the
isomorphism $C^*(A ,A) \simeq C^*(A,A^\vee)$.


title:
Bosonic topological insulator in three dimensions and the statistical
  Witten effect

abstract:
  It is well-known that one signature of the three-dimensional electron
topological insulator is the Witten effect: if the system is coupled to a
compact electromagnetic gauge field, a monopole in the bulk acquires a
half-odd-integer polarization charge. In the present work, we propose a
corresponding phenomenon for the topological insulator of bosons in 3d
protected by particle number conservation and time-reversal symmetry. We claim
that although a monopole inside a topological insulator of bosons can remain
electrically neutral, its statistics are transmuted from bosonic to fermionic.
We demonstrate that this ``statistical Witten effect" directly implies that if
the surface of the topological insulator is neither gapless, nor spontaneously
breaks the symmetry, it necessarily supports an intrinsic two-dimensional
topological order. Moreover, the surface properties cannot be fully realized in
a purely 2d system. We also confirm that the surface phases of the bosonic
topological insulator proposed by Vishwanath and Senthil (arXiv:1209.3058)
provide a consistent termination of a bulk exhibiting the statistical Witten
effect. In a companion paper, we will provide an explicit field-theoretic,
lattice-regularized, construction of the 3d topological insulator of bosons,
employing a parton decomposition and subsequent condensation of parton-monopole
composites.


title:
A survey of surface braid groups and the lower algebraic K-theory of
  their group rings

abstract:
  We give a survey of the theory of surface braid groups and the lower
algebraic K-theory of their group rings. We recall several definitions and
describe various properties of surface braid groups, such as the existence of
torsion, orderability, linearity, and their relation both with mapping class
groups and with the homotopy groups of the 2-sphere. The braid groups of the
2-sphere and the real projective plane are of particular interest because they
possess elements of finite order, and we discuss in detail their torsion and
the classification of their finite and virtually cyclic subgroups. Finally, we
outline the methods used to study the lower algebraic K-theory of the group
rings of surface braid groups, highlighting recent results concerning the braid
groups of the 2-sphere and the real projective plane.


title: Wave computation on the Poincar\'e dodecahedral space

abstract:
  We compute the waves propagating on a compact 3-manifold of constant positive
curvature with a non trivial topology: the Poincar\'e dodecahedral space that
is a plausible model of multi-connected universe. We transform the Cauchy
problem to a mixed problem posed on a fundamental domain determined by the
quaternionic calculus. We adopt a variational approach using a space of finite
elements that is invariant under the action of the binary icosahedral group.
The computation of the transient waves is validated with their spectral
analysis by computing a lot of eigenvalues of the Laplace-Beltrami operator.


title:
Molecular-Kinetic Simulations of Escape from the Ex-planet and
  Exoplanets: Criterion for Transonic Flow

abstract:
  The equations of gas dynamics are extensively used to describe atmospheric
loss from solar system bodies and exoplanets even though the boundary
conditions at infinity are not uniquely defined. Using molecular-kinetic
simulations that correctly treat the transition from the continuum to the
rarefied region, we confirm that the energy-limited escape approximation is
valid when adiabatic expansion is the dominant cooling process. However, this
does not imply that the outflow goes sonic. In fact in the sonic regime, the
energy limited approximation can significantly under estimate the escape rate.
Rather large escape rates and concomitant adiabatic cooling can produce
atmospheres with subsonic flow that are highly extended. Since this affects the
heating rate of the upper atmosphere and the interaction with external fields
and plasmas, we give a criterion for estimating when the outflow goes transonic
in the continuum region. This is applied to early terrestrial atmospheres,
exoplanet atmospheres, and the atmosphere of the ex-planet, Pluto, all of which
have large escape rates. The paper and its erratum, combined here, are
published: ApJL 768, L4 (2013); ApJ, 779, L30 (2013).


title: Random truncations of Haar distributed matrices and bridges

abstract:
  Let $U$ be a Haar distributed matrix in $\mathbb U(n)$ or $\mathbb O (n)$. In
a previous paper, we proved that after centering, the two-parameter process
\[T^{(n)} (s,t) = \sum_{i \leq \lfloor ns \rfloor, j \leq \lfloor nt\rfloor}
|U_{ij}|^2\] converges in distribution to the bivariate tied-down Brownian
bridge. In the present paper, we replace the deterministic truncation of $U$ by
a random one, where each row (resp. column) is chosen with probability $s$
(resp. $t$) independently. We prove that the corresponding two-parameter
process, after centering and normalization by $n^{-1/2}$ converges to a
Gaussian process. On the way we meet other interesting convergences.


title: Une in\'egalit\'e de Cheeger pour le spectre de Steklov

abstract:
  We prove a Cheeger inequality for the first positive Steklov eigenvalue. It
involves two isoperimetric constants.


title: Ultra-short strong excitation of two-level systems

abstract:
  We present a model describing the use of ultra-short strong pulses to control
the population of the excited level of a two-level quantum system. In
particular, we study an off-resonance excitation with a few cycles pulse which
presents a smooth phase jump i.e. a change of the pulse's phase which is not
step-like, but happens over a finite time interval. A numerical solution is
given for the time-dependent probability amplitude of the excited level. The
control of the excited level's population is obtained acting on the shape of
the phase transient, and other parameters of the excitation pulse.


title: A lower bound on dimension reduction for trees in \ell_1

abstract:
  There is a constant c > 0 such that for every $\epsilon \in (0,1)$ and $n
\geq 1/\epsilon^2$, the following holds. Any mapping from the $n$-point star
metric into $\ell_1^d$ with bi-Lipschitz distortion $1+\epsilon$ requires
dimension $$d \geq {c\log n\over \epsilon^2\log (1/\epsilon)}.$$


title: Invariants of complex structures on nilmanifolds

abstract:
  Let $(N, J)$ be a simply connected $2n$-dimensional nilpotent Lie group
endowed with an invariant complex structure. We define a left invariant
Riemannian metric on $N$ compatible with $J$ to be minimal, if it minimizes the
norm of the invariant part of the Ricci tensor among all compatible metrics
with the same scalar curvature. In [L1], J. Lauret proved that minimal metrics
(if any) are unique up to isometry and scaling. This uniqueness allows us to
distinguish two complex structures with Riemannian data, giving rise to a great
deal of invariants.
  We show how to use a Riemannian invariant: the eigenvalues of the Ricci
operator, polynomial invariants and discrete invariants to give an alternative
proof of the pairwise non-isomorphism between the structures which have
appeared in the classification of abelian complex structures on 6-dimensional
nilpotent Lie algebras given in [ABD]. We also present some continuous families
in dimension 8.


title:
Typical and rare fluctuations in nonlinear driven diffusive systems with
  dissipation

abstract:
  We consider fluctuations of the dissipated energy in nonlinear driven
diffusive systems subject to bulk dissipation and boundary driving. With this
aim, we extend the recently-introduced macroscopic fluctuation theory to
nonlinear driven dissipative media, starting from the fluctuating hydrodynamic
equations describing the system mesoscopic evolution. Interestingly, the action
associated to a path in mesoscopic phase-space, from which large-deviation
functions for macroscopic observables can be derived, has the same simple form
as in non-dissipative systems. This is a consequence of the quasi-elasticity of
microscopic dynamics, required in order to have a nontrivial competition
between diffusion and dissipation at the mesoscale. Euler-Lagrange equations
for the optimal density and current fields that sustain an arbitrary
dissipation fluctuation are also derived. A perturbative solution thereof shows
that the probability distribution of small fluctuations is always gaussian, as
expected from the central limit theorem. On the other hand, strong separation
from the gaussian behavior is observed for large fluctuations, with a
distribution which shows no negative branch, thus violating the
Gallavotti-Cohen fluctuation theorem as expected from the irreversibility of
the dynamics. The dissipation large-deviation function exhibits simple and
general scaling forms for weakly and strongly dissipative systems, with large
fluctuations favored in the former case but heavily supressed in the latter.
(...) [see complete abstract by downloading the paper]


title: Collapsing of the Chern-Ricci flow on elliptic surfaces

abstract:
  We investigate the Chern-Ricci flow, an evolution equation of Hermitian
metrics generalizing the Kahler-Ricci flow, on elliptic bundles over a Riemann
surface of genus greater than one. We show that, starting at any Gauduchon
metric, the flow collapses the elliptic fibers and the metrics converge to the
pullback of a Kahler-Einstein metric from the base. Some of our estimates are
new even for the Kahler-Ricci flow. A consequence of our result is that, on
every minimal non-Kahler surface of Kodaira dimension one, the Chern-Ricci flow
converges in the sense of Gromov-Hausdorff to an orbifold Kahler-Einstein
metric on a Riemann surface.


title: Fine-tuning in GGM and the 126 GeV Higgs particle

abstract:
  In this paper we reanalyze the issue of fine-tuning in supersymmetric models
which feature Generalized Gauge Mediation (GGM) in the light of recent
measurement of the mass of the light Higgs particle and taking into account
available data on the value of the muon magnetic moment $g_\mu-2$. We consider
GGM models with 3, 5 and 6 input parameters and reduce the fine-tuning by
assuming simple relations between them at the high scale. We are able to find
solutions which give the correct value of the light Higgs mass and are less
fine-tuned than models with standard gauge mediation (and with gravity
mediation), however one never finds fine-tung measure lower than about $10^2$
if one neglects the data on $g_\mu-2$ and and about four times more if one
takes the constraint given by $g_\mu-2$ into account. In general the current
$g_\mu-2$ data push the models towards the high fine-tuning region. It is
interesting to note, that once one removes the contributions to the finetuning
induced by $\mu$ and $B_\mu$, then in the case with neglected $g_\mu-2$
constraint one can easily find realistic vacua with fine-tuning of order 1 or
lower, while the fine-tung remains always large when the $g_\mu-2$ constraint
is enforced. One should note, that in the last case even a small shift of the
light Higgs mass towards smaller values both reduces fine-tuning and helps to
improve agreement of a model with $g_\mu-2$ data.


title: Comment on "Absence of spin liquid in non-frustrated correlated systems"

abstract:
  In a recent Letter, Hassan and S\'en\'echal [1] discussed the existence of a
spin-liquid phase of the half-filled Hubbard model on the honeycomb lattice.
Using schemes, such as the variational cluster approximation (VCA) and the
cluster dynamical mean field theory (CDMFT) in combination with exact
diagonalization (ED), they argued that a single bath orbital per site of the
six-atom unit cell is insufficient and leads to the erroneous conclusion that
the system is gapped for all nonzero values of the onsite Coulomb interaction
$U$. In contrast, we point out here that, in the case of the honeycomb lattice,
six bath levels per six-site unit cell are perfectly adequate for the
description of short-range correlations. Instead, we demonstrate that it is the
violation of long-range translation symmetry inherent in CDMFT-like schemes
which opens a gap at Dirac points. The gap found at small $U$ therefore does
not correspond to a Mott gap. As a result, present CDMFT schemes are not
suitable for the identification of a spin-liquid phase on the honeycomb
lattice. [1] S.R. Hassan and D. S\'en\'echal, Phys. Rev. Lett. 110, 096402
(2013).


title: Spatial partitioning improves the reliability of biochemical signaling

abstract:
  Spatial heterogeneity is a hallmark of living systems, even at the molecular
scale in individual cells. A key example is the partitioning of membrane-bound
proteins via lipid domain formation or cytoskeleton-induced corralling. Yet the
impact of this spatial heterogeneity on biochemical signaling processes is
poorly understood. Here we demonstrate that partitioning improves the
reliability of biochemical signaling. We exactly solve a stochastic model
describing a ubiquitous motif in membrane signaling. The solution reveals that
partitioning improves signaling reliability via two effects: it moderates the
non-linearity of the switching response, and it reduces noise in the response
by suppressing correlations between molecules. An optimal partition size arises
from a trade-off between minimizing the number of proteins per partition to
improve signaling reliability and ensuring sufficient proteins per partition to
maintain signal propagation. The predicted optimal partition size agrees
quantitatively with experimentally observed systems. These results persist in
spatial simulations with explicit diffusion barriers. Our findings suggest that
molecular partitioning is not merely a consequence of the complexity of
cellular substructures, but also plays an important functional role in cell
signaling.


title: Spin Mixing in Spinor Fermi Gases

abstract:
  We study a spinor fermionic system under the effect of spin-exchange
interaction. We focus on the interplay between the spin-exchange interaction
and the effective quadratic Zeeman shift. We examine the static and the dynamic
properties of both two- and many-body system. We find that the spin-exchange
interaction induces coherent Rabi oscillation in the two-body system, but the
oscillation is quickly damped when the system is extended to the many-body
case.


title: On restricted families of projections in R^3

abstract:
  We study projections onto non-degenerate one-dimensional families of lines
and planes in $\mathbb{R}^{3}$. Using the classical potential theoretic
approach of R. Kaufman, one can show that the Hausdorff dimension of at most
$1/2$-dimensional sets $B \subset \mathbb{R}^{3}$ is typically preserved under
one-dimensional families of projections onto lines. We improve the result by an
$\varepsilon$, proving that if $\dim_{\mathrm{H}} B = s > 1/2$, then the
packing dimension of the projections is almost surely at least $\sigma(s) >
1/2$. For projections onto planes, we obtain a similar bound, with the
threshold $1/2$ replaced by $1$. In the special case of self-similar sets $K
\subset \mathbb{R}^{3}$ without rotations, we obtain a full Marstrand type
projection theorem for one-parameter families of projections onto lines. The
$\dim_{\mathrm{H}} K \leq 1$ case of the result follows from recent work of M.
Hochman, but the $\dim_{\mathrm{H}} K > 1$ part is new: with this assumption,
we prove that the projections have positive length almost surely.


title:
The importance sampling technique for understanding rare events in
  Erd\H{o}s-R\'enyi random graphs

abstract:
  In dense Erd\H{o}s-R\'enyi random graphs, we are interested in the events
where large numbers of a given subgraph occur. The mean behavior of subgraph
counts is known, and only recently were the related large deviations results
discovered. Consequently, it is natural to ask, can one develop efficient
numerical schemes to estimate the probability of an Erd\H{o}s-R\'enyi graph
containing an excessively large number of a fixed given subgraph? Using the
large deviation principle we study an importance sampling scheme as a method to
numerically compute the small probabilities of large triangle counts occurring
within Erd\H{o}s-R\'enyi graphs. We show that the exponential tilt suggested
directly by the large deviation principle does not always yield an optimal
scheme. The exponential tilt used in the importance sampling scheme comes from
a generalized class of exponential random graphs. Asymptotic optimality, a
measure of the efficiency of the importance sampling scheme, is achieved by a
special choice of the parameters in the exponential random graph that makes it
indistinguishable from an Erd\H{o}s-R\'enyi graph conditioned to have many
triangles in the large network limit. We show how this choice can be made for
the conditioned Erd\H{o}s-R\'enyi graphs both in the replica symmetric phase as
well as in parts of the replica breaking phase to yield asymptotically optimal
numerical schemes to estimate this rare event probability.


title: Torsion in kernels of induced maps on divisor class groups

abstract:
  We investigate torsion elements in the kernel of the map on divisor class
groups of excellent local normal domains A and A/I, for an ideal I of finite
projective dimension. The motivation for this work is a result of
Griffith-Weston which applies when I is principal.


title:
Unavoidable CMB spectral features and blackbody photosphere of our
  Universe

abstract:
  Spectral features in the CMB energy spectrum contain a wealth of information
about the physical processes in the early Universe, z < 2 x 10^6. The CMB
spectral distortions are complementary to all other probes of cosmology. In
fact, most of the information contained in the CMB spectrum is inaccessible by
any other means. This review outlines the main physics behind the spectral
features in the CMB throughout the history of the Universe, concentrating on
the distortions which are inevitable and must be present at a level observable
by the next generation of proposed CMB experiments. The spectral distortions
considered here include spectral features from cosmological recombination,
resonant scattering of CMB by metals during reionization which allows us to
measure their abundances, y-type distortions during and after reionization and
\mu-type and i-type (intermediate between \mu and y) distortions created at
redshifts z > 1.5 x 10^4.


title:
Asymptotics and regularity of flat solutions to fully nonlinear elliptic
  problems

abstract:
  In this work we establish local $C^{2,\alpha}$ regularity estimates for flat
solutions to non-convex fully nonlinear elliptic equations provided the
coefficients and the source function are of class $C^{0,\alpha}$. For problems
with merely continuous data, we prove that flat solutions are locally
$C^{1,\text{Log-Lip}}$.


title: Non-Hermitian Quantum Annealing in the Antiferromagnetic Ising Chain

abstract:
  A non-Hermitian quantum optimization algorithm is created and used to find
the ground state of an antiferromagnetic Ising chain. We demonstrate
analytically and numerically (for up to N=1024 spins) that our approach leads
to a significant reduction of the annealing time that is proportional to $\ln
N$, which is much less than the time (proportional to $N^2$) required for the
quantum annealing based on the corresponding Hermitian algorithm. We propose to
use this approach to achieve similar speed-up for NP-complete problems by using
classical computers in combination with quantum algorithms.

categories: quant-ph math-ph math.MP physics.comp-ph


title: On Sharing Private Data with Multiple Non-Colluding Adversaries

abstract:
  We present SPARSI, a theoretical framework for partitioning sensitive data
across multiple non-colluding adversaries. Most work in privacy-aware data
sharing has considered disclosing summaries where the aggregate information
about the data is preserved, but sensitive user information is protected.
Nonetheless, there are applications, including online advertising, cloud
computing and crowdsourcing markets, where detailed and fine-grained user-data
must be disclosed. We consider a new data sharing paradigm and introduce the
problem of privacy-aware data partitioning, where a sensitive dataset must be
partitioned among k untrusted parties (adversaries). The goal is to maximize
the utility derived by partitioning and distributing the dataset, while
minimizing the amount of sensitive information disclosed. The data should be
distributed so that an adversary, without colluding with other adversaries,
cannot draw additional inferences about the private information, by linking
together multiple pieces of information released to her. The assumption of no
collusion is both reasonable and necessary in the above application domains
that require release of private user information. SPARSI enables us to formally
define privacy-aware data partitioning using the notion of sensitive properties
for modeling private information and a hypergraph representation for describing
the interdependencies between data entries and private information. We show
that solving privacy-aware partitioning is, in general, NP-hard, but for
specific information disclosure functions, good approximate solutions can be
found using relaxation techniques. Finally, we present a local search algorithm
applicable to generic information disclosure functions. We apply SPARSI
together with the proposed algorithms on data from a real advertising scenario
and show that we can partition data with no disclosure to any single
advertiser.


title: Geodesic-based Salient Object Detection

abstract:
  Saliency detection has been an intuitive way to provide useful cues for
object detection and segmentation, as desired for many vision and graphics
applications. In this paper, we provided a robust method for salient object
detection and segmentation. Other than using various pixel-level contrast
definitions, we exploited global image structures and proposed a new geodesic
method dedicated for salient object detection. In the proposed approach, a new
geodesic scheme, namely geodesic tunneling is proposed to tackle with textures
and local chaotic structures. With our new geodesic approach, a geodesic
saliency map is estimated in correspondence to spatial structures in an image.
Experimental evaluation on a salient object benchmark dataset validated that
our algorithm consistently outperformed a number of the state-of-art saliency
methods, yielding higher precision and better recall rates. With the robust
saliency estimation, we also present an unsupervised hierarchical salient
object cut scheme simply using adaptive saliency thresholding, which attained
the highest score in our F-measure test. We also applied our geodesic cut
scheme to a number of image editing tasks as demonstrated in additional
experiments.


title: Generating permutations with a given major index

abstract:
  In [S. Effler, F. Ruskey, A CAT algorithm for listing permutations with a
given number of inversions, {\it I.P.L.}, 86/2 (2003)] the authors give an
algorithm, which appears to be CAT, for generating permutations with a given
major index. In the present paper we give a new algorithm for generating a Gray
code for subexcedant sequences. We show that this algorithm is CAT and derive
it into a CAT generating algorithm for permutations with a given major index.


title:
Progress in Modeling Very Low Mass Stars, Brown Dwarfs, and Planetary
  Mass Objects

abstract:
  We review recent advancements in modeling the stellar to substellar
transition. The revised molecular opacities, solar oxygen abundances and cloud
models allow to reproduce the photometric and spectroscopic properties of this
transition to a degree never achieved before, but problems remain in the
important M-L transition characteristic of the effective temperature range of
characterizable exoplanets. We discuss of the validity of these classical
models. We also present new preliminary global Radiation HydroDynamical M
dwarfs simulations.


title:
Non-planarity and metric Diophantine approximation for systems of linear
  forms

abstract:
  In this paper we develop a general theory of metric Diophantine approximation
for systems of linear forms. A new notion of `weak non-planarity' of manifolds
and more generally measures on the space of $m\times n$ matrices over $\Bbb R$
is introduced and studied. This notion generalises the one of non-planarity in
$\Bbb R^n$ and is used to establish strong (Diophantine) extremality of
manifolds and measures. The notion of weak non-planarity is shown to be `near
optimal' in a certain sense. Beyond the above main theme of the paper, we also
develop a corresponding theory of inhomogeneous and weighted Diophantine
approximation. In particular, we extend the recent inhomogeneous transference
results due to Beresnevich and Velani and use them to bring the inhomogeneous
theory in balance with its homogeneous counterpart.


title: Group distance magic graphs $G\times C_n$

abstract:
  A $\Gamma$-distance magic labeling of a graph $G=(V,E)$ with $|V | = n$ is a
bijection $f$ from $V$ to an Abelian group $\Gamma$ of order $n$ such that the
weight $w(x)=\sum_{y\in N_G(x)}f(y)$ of every vertex $x \in V$ is equal to the
same element $\mu \in \Gamma$, called the \emph{magic constant}.
  In this paper we will show that if $G$ is a graph of order $n=2^{p}(2k+1)$
for some natural numbers $p$, $k$ such that $\deg(v)\equiv c \imod {2^{p+2}}$
for some constant $c$ for any $v\in V(G)$, then there exists a
$\Gamma$-distance magic labeling for any Abelian group $\Gamma$ of order $4n$
for the direct product $G\times C_4$. Moreover if $c$ is even then there exists
a $\Gamma$-distance magic labeling for any Abelian group $\Gamma$ of order $8n$
for the direct product $G\times C_8$.


title:
An Improvement to Levenshtein's Upper Bound on the Cardinality of
  Deletion Correcting Codes

abstract:
  We consider deletion correcting codes over a q-ary alphabet. It is well known
that any code capable of correcting s deletions can also correct any
combination of s total insertions and deletions. To obtain asymptotic upper
bounds on code size, we apply a packing argument to channels that perform
different mixtures of insertions and deletions. Even though the set of codes is
identical for all of these channels, the bounds that we obtain vary. Prior to
this work, only the bounds corresponding to the all insertion case and the all
deletion case were known. We recover these as special cases. The bound from the
all deletion case, due to Levenshtein, has been the best known for more than
forty five years. Our generalized bound is better than Levenshtein's bound
whenever the number of deletions to be corrected is larger than the alphabet
size.


title: Feedback Particle Filter

abstract:
  A new formulation of the particle filter for nonlinear filtering is
presented, based on concepts from optimal control, and from the mean-field game
theory. The optimal control is chosen so that the posterior distribution of a
particle matches as closely as possible the posterior distribution of the true
state given the observations. This is achieved by introducing a cost function,
defined by the Kullback-Leibler (K-L) divergence between the actual posterior,
and the posterior of any particle.
  The optimal control input is characterized by a certain Euler-Lagrange (E-L)
equation, and is shown to admit an innovation error-based feedback structure.
For diffusions with continuous observations, the value of the optimal control
solution is ideal. The two posteriors match exactly, provided they are
initialized with identical priors. The feedback particle filter is defined by a
family of stochastic systems, each evolving under this optimal control law.
  A numerical algorithm is introduced and implemented in two general examples,
and a neuroscience application involving coupled oscillators. Some preliminary
numerical comparisons between the feed- back particle filter and the bootstrap
particle filter are described.


title: Swarming in disordered environments

abstract:
  The emergence of collective motion, also known as flocking or swarming, in
groups of moving individuals who orient themselves using only information from
their neighbors is a very general phenomenon that is manifested at multiple
spatial and temporal scales. Swarms that occur in natural environments
typically have to contend with spatial disorder such as obstacles that hinder
an individual's motion or communication with neighbors. We study swarming
particles, with both aligning and repulsive interactions, on percolated
networks where topological disorder is modeled by the random removal of lattice
bonds. We find that an infinitesimal amount of disorder can completely suppress
swarming for particles that utilize only alignment interactions suggesting that
alignment alone is insufficient. The addition of repulsive forces between
particles produces a critical phase transition from a collectively moving swarm
to a disordered gas-like state. This novel phase transition is entirely driven
by the amount of topological disorder in the particles environment and displays
critical features that are similar to those of 2D percolation, while occurring
at a value of disorder that is far from the percolation critical point.


title: Analyzing the Toffoli gate in disordered circuit QED

abstract:
  We study the effects of imperfections on the fidelity of the Toffoli gate
recently realized in a circuit~QED setup using quantum control methods. The
noise is introduced in the interqubits interactions. The coupling constants are
no longer fixed; instead, they fluctuate around average values obeying some
given probability density functions characterizing the dynamical-imperfection
case. We also consider the static-imperfection case in which the values of the
coupling constants are not exactly known. We obtain a more robust gate by
modifying the quantum optimization problem using a weighted average of the
fidelity over an interval of coupling values as the objective functional.


title: Singularity resolution from polymer quantum matter

abstract:
  We study the polymeric nature of quantum matter fields using the example of a
Friedmann-Lemaitre-Robertson-Walker universe sourced by a minimally coupled
massless scalar field. The model is treated in the symmetry reduced regime via
deparametrization techniques, with the scale factor playing the role of time.
Subsequently, the remaining dynamic degrees of freedom corresponding to the
matter are polymer quantized. The analysis of the resulting genuine quantum
dynamic shows that the big bang singularity is resolved, although with the form
of the resolution differing significantly from that in the models with matter
clocks: dynamically, the singularity is made passable rather than avoided.
Furthermore, this analysis exposes crucial limitations to the so-called
effective dynamic in loop quantum cosmology when applied outside of the most
basic isotropic settings.


title: Teach Network Science to Teenagers

abstract:
  We discuss our outreach efforts to introduce school students to network
science and explain why networks researchers should be involved in such
outreach activities. We provide overviews of modules that we have designed for
these efforts, comment on our successes and failures, and illustrate the
potentially enormous impact of such outreach efforts.

categories: physics.ed-ph cs.SI math.CO physics.pop-ph physics.soc-ph


title: Electronic and optical properties of carbon nanodisks and nanocones

abstract:
  A theoretical study of the electronic properties of nanodisks and nanocones
is presented within the framework of a tight-binding scheme. The electronic
densities of states and absorption coefficients are calculated for such
structures with different sizes and topologies. A discrete position
approximation is used to describe the electronic states taking into account the
effect of the overlap integral to first order. For small finite systems, both
total and local densities of states depend sensitively on the number of atoms
and characteristic geometry of the structures. Results for the local densities
of charge reveal a finite charge distribution around some atoms at the apices
and borders of the cone structures. For structures with more than 5000 atoms,
the contribution to the total density of states near the Fermi level
essentially comes from states localized at the edges. For other energies the
average density of states exhibits similar features to the case of a graphene
lattice. Results for the absorption spectra of nanocones show a peculiar
dependence on the photon polarization in the infrared range for all
investigated structures.


title: Characterizing scientific production and consumption in Physics

abstract:
  We analyze the entire publication database of the American Physical Society
generating longitudinal (50 years) citation networks geolocalized at the level
of single urban areas. We define the knowledge diffusion proxy, and scientific
production ranking algorithms to capture the spatio-temporal dynamics of
Physics knowledge worldwide. By using the knowledge diffusion proxy we identify
the key cities in the production and consumption of knowledge in Physics as a
function of time. The results from the scientific production ranking algorithm
allow us to characterize the top cities for scholarly research in Physics.
Although we focus on a single dataset concerning a specific field, the
methodology presented here opens the path to comparative studies of the
dynamics of knowledge across disciplines and research areas


title:
Secure Degrees of Freedom of the Gaussian Wiretap Channel with Helpers
  and No Eavesdropper CSI: Blind Cooperative Jamming

abstract:
  We consider the Gaussian wiretap channel with M helpers, where no
eavesdropper channel state information (CSI) is available at the legitimate
entities. The exact secure d.o.f. of the Gaussian wiretap channel with M
helpers with perfect CSI at the transmitters was found in [1], [2] to be
M/(M+1). One of the key ingredients of the optimal achievable scheme in [1],
[2] is to align cooperative jamming signals with the information symbols at the
eavesdropper to limit the information leakage rate. This required perfect
eavesdropper CSI at the transmitters. Motivated by the recent result in [3], we
propose a new achievable scheme in which cooperative jamming signals span the
entire space of the eavesdropper, but are not exactly aligned with the
information symbols. We show that this scheme achieves the same secure d.o.f.
of M/(M+1) in [1], [2] but does not require any eavesdropper CSI; the
transmitters blindly cooperative jam the eavesdropper.


title:
Motion induced second order temperature and y-type anisotropies after
  the subtraction of linear dipole in the CMB maps

abstract:
  y-type spectral distortions of the cosmic microwave background allow us to
detect clusters and groups of galaxies, filaments of hot gas and the
non-uniformities in the warm hot intergalactic medium. Several CMB experiments
(on small areas of sky) and theoretical groups (for full sky) have recently
published y-type distortion maps. We propose to search for two artificial hot
spots in such y-type maps resulting from the incomplete subtraction of the
effect of the motion induced dipole on the cosmic microwave background sky.
This dipole introduces, at second order, additional temperature and
y-distortion anisotropy on the sky of amplitude few \mu K which could
potentially be measured by Planck HFI and Pixie experiments and can be used as
a source of cross channel calibration by CMB experiments. This y-type
distortion is present in every pixel and is not the result of averaging the
whole sky. This distortion, calculated exactly from the known linear dipole,
can be subtracted from the final y-type maps, if desired.


title:
Exploring wind-driving dust species in cool luminous giants II.
  Constraints from photometry of M-type AGB stars

abstract:
  The heavy mass loss observed in evolved asymptotic giant branch (AGB) stars
is usually attributed to a two-stage process: atmospheric levitation by
pulsation-induced shock waves, followed by radiative acceleration of newly
formed dust grains. The dust transfers momentum to the surrounding gas through
collisions and thereby triggers a general outflow. Radiation-hydrodynamical
models of M-type AGB stars suggest that these winds can be driven by photon
scattering -- in contrast to absorption -- on Fe-free silicate grains of sizes
0.1--1\,$\mu$m. In this paper we study photometric constraints for wind-driving
dust species in M-type AGB stars, as part of an ongoing effort to identify
likely candidates among the grain materials observed in circumstellar
envelopes. To investigate the scenario of stellar winds driven by photon
scattering on dust, and to explore how different optical and chemical
properties of wind-driving dust species affect photometry we focus on two sets
of dynamical models atmospheres: (i) models using a detailed description for
the growth of Mg$_2$SiO$_4$ grains, taking into account both scattering and
absorption cross-sections when calculating the radiative acceleration, and (ii)
models using a parameterized dust description, constructed to represent
different chemical and optical dust properties. By comparing synthetic
photometry from these two sets of models to observations of M-type AGB stars we
can provide constraints on the properties of wind-driving dust species.
Photometry from wind models with a detailed description for the growth of
Mg$_2$SiO$_4$ grains reproduces well both the values and the time-dependent
behavior of observations of M-type AGB stars, providing further support for the
scenario of winds driven by photon scattering on dust.


title: Explaining the Sr and Ba Scatter in Extremely Metal-Poor Stars

abstract:
  Compilations of abundances of Strontium and Barium in extremely metal-poor
stars show that an apparent cutoff is observed for [Sr/Ba] at [Fe/H]$<$-3.6 and
large fluctuations for [Fe/H]$>$-3.6 with a clear upper bound depending on
metallicity. We study the factors that place upper limits on the logarithmic
ratio [Sr/Ba]. A model is developed in which the collapses of type II
supernovae are found to reproduce many of the features seen in the data. This
model is consistent with galactic chemical evolution constraints of
light-element enrichment in metal-poor stars. Effects of turbulence in an
explosive site have also been simulated, and are found to be important in
explaining the large scatter observed in the [Sr/Ba] data.


title: Energy and Sampling Constrained Asynchronous Communication

abstract:
  The minimum energy, and, more generally, the minimum cost, to transmit one
bit of information has been recently derived for bursty communication when
information is available infrequently at random times at the transmitter. This
result assumes that the receiver is always in the listening mode and samples
all channel outputs until it makes a decision. If the receiver is constrained
to sample only a fraction f>0 of the channel outputs, what is the cost penalty
due to sparse output sampling?
  Remarkably, there is no penalty: regardless of f>0 the asynchronous capacity
per unit cost is the same as under full sampling, ie, when f=1. There is not
even a penalty in terms of decoding delay---the elapsed time between when
information is available until when it is decoded. This latter result relies on
the possibility to sample adaptively; the next sample can be chosen as a
function of past samples. Under non-adaptive sampling, it is possible to
achieve the full sampling asynchronous capacity per unit cost, but the decoding
delay gets multiplied by 1/f. Therefore adaptive sampling strategies are of
particular interest in the very sparse sampling regime.


title:
Finite-size and Fluctuation Effects on Phase Transition and Critical
  Phenomena using Mean-Field Approach Based on Renormalized $\phi^{4}$ Model:
  I. Theory

abstract:
  An investigation of the spatial fluctuations and their manifestations in the
vicinity of the quantum critical point within the framework of the renormalized
$\phi^{4}$ theory is proposed. Relevant features are reported through the
Ginzburg-Landau-Wilson (GLW)-based calculations, combined with an efficient non
perturbative technique. Both the dimension and size, but also microscopic
details of the system, leading to critical behavior, and strongly deviating
from the classical mean-field approach far from the thermodynamic limit, are
taken into account. Further, the important role that harmonic and anharmonic
fluctuations and finite-size effects can play in the determination of the
characteristic properties of corresponding various systems, involving phase
transitions and critical phenomena, is then discussed in detail with emphasis
on the qualitative validity of the analysis


title: Orderability, contact non-squeezing, and Rabinowitz Floer homology

abstract:
  We study Liouville fillable contact manifolds $(\Sigma,\xi)$ with non-zero
Rabinowitz Floer homology and assign spectral numbers to paths of
contactomorphisms. As a consequence we prove that
$\widetilde{\mathrm{Cont}_0}(\Sigma,\xi)$ is orderable in the sense of
Eliashberg and Polterovich. This provides a new class of orderable contact
manifolds. If the contact manifold is in addition periodic or a prequantization
space $M \times S^1$ for $M$ a Liouville manifold, then we construct a contact
capacity. This can be used to prove a general non-squeezing result, which
amongst other examples in particular recovers the beautiful non-squeezing
results from [EKP06].


title:
Effects in the Anomalistic Period of Celestial Bodies due to a
  Logarithmic Correction to the Newtonian Gravitational Potential

abstract:
  We study the motion of a secondary celestial body under the influence of the
logarithmic corrected gravitational force of a primary one. This kind of
correction was introduced by Fabris et al. (2009). We derive two equations to
compute the rate of change of the periastron w.r.t. the eccentric anomaly and
its total variation over one revolution, In a kinematical sense, this influence
produces an apsidal motion. We perform numerical estimations for Mercury and
for the companion star of the pulsar PSR 1913+16. We also consider the case of
the artificial Earth satellite GRACE-A, but the results present a low degree of
reliability from a practical standpoint


title: Dissipative Cylindrical Collapse of Charged Anisotropic Fluid

abstract:
  We have studied the dynamics of a cylindrical column of anisotropic, charged
fluid which is experiencing dissipation in the form of heat flow,
free-streaming radiation, and shearing viscosity, undergoing gravitational
collapse. We calculate the Einstein-Maxwell field equations and, using the
Darmois junction conditions, match the interior non-static cylindrically
symmetric space-time with the exterior anisotropic, charged, cylindrically
symmetric space-time. The behavior of the density, pressure and luminosity of
the collapsing matter has been analyzed. From the dynamical equations, the
effect of charge and dissipative quantities over the cylindrical collapse are
studied. Finally, we have derived the solutions for the collapsing matter which
is valid during the later stages of collapse and have discussed the
significance from a physical standpoint.


title:
Correlated Event Excesses in LHC SUSY Searches at 7 & 8 TeV: New Physics
  or Conspiring Noise?

abstract:
  We examine the ATLAS and CMS 7 & 8 TeV multijet supersymmetry (SUSY) searches
requiring the incidence of a single lepton in the framework of the
supersymmetric grand unified model No-Scale Flipped SU(5) with extra
vector-like flippon multiplets derived from F-Theory, or F-SU(5) for short.
Investigated are five multijet+lepton SUSY searches: 4.7/fb ATLAS 7 TeV gluino
and light stop searches, as well as 13/fb ATLAS and 9.7/fb CMS 8 TeV light stop
searches. Most significantly, all five leptonic SUSY searches represent
statistically independent data samples. Findings show that all five orthogonal
sets of leptonic LHC observations give a lower bound to the gaugino mass scale
at M_{1/2} >= 680 GeV, with all the current best fits correlating within a
narrow region. Furthermore, eight statistically independent LHC SUSY search
regions (leptonic + all-hadronic) accessible to the No-Scale F-SU(5) model
space intersect with all the currently operating beyond the Standard Model
experiments within the range of M_{1/2} = 680-850 GeV, with the upper bound
established by the lower experimental limit of the anomalous magnetic moment
(g_{mu}-2)/2 of the muon. We emphasize that this region of the F-SU(5) model
space may not be fully probed by leptonic SUSY searches at the LHC until the 13
TeV LHC energizes in 2015. Additionally, we describe an efficient technique for
the effective statistical disentanglement of searches sensitive to mutually
overlapping event spaces.


title:
Finding the Right Set of Users: Generalized Constraints for Group
  Recommendations

abstract:
  Recently, group recommendations have attracted considerable attention. Rather
than recommending items to individual users, group recommenders recommend items
to groups of users. In this position paper, we introduce the problem of forming
an appropriate group of users to recommend an item when constraints apply to
the members of the group. We present a formal model of the problem and an
algorithm for its solution. Finally, we identify several directions for future
work.