title: Satisfiability threshold for random regular NAE-SAT

abstract:
  We consider the random regular $k$-NAE-SAT problem with $n$ variables each
appearing in exactly $d$ clauses. For all $k$ exceeding an absolute constant
$k_0$, we establish explicitly the satisfiability threshold $d_*=d_*(k)$. We
prove that for $d<d_*$ the problem is satisfiable with high probability while
for $d>d_*$ the problem is unsatisfiable with high probability. If the
threshold $d_*$ lands exactly on an integer, we show that the problem is
satisfiable with probability bounded away from both zero and one. This is the
first result to locate the exact satisfiability threshold in a random
constraint satisfaction problem exhibiting the condensation phenomenon
identified by Krzakala et al. (2007). Our proof verifies the one-step replica
symmetry breaking formalism for this model. We expect our methods to be
applicable to a broad range of random constraint satisfaction problems and
combinatorial problems on random graphs.


title:
Stable finite element pair for Stokes problem and discrete Stokes
  complex on quadrilateral grids

abstract:
  In this paper, we first construct a nonconforming finite element pair for the
incompressible Stokes problem on quadrilateral grids, and then construct a
discrete Stokes complex associated with that finite element pair. The finite
element spaces involved consist of piecewise polynomials only, and the
divergence-free condition is imposed in a primal formulation. Combined with
some existing results, these constructions can be generated onto grids that
consist of both triangular and quadrilateral cells.


title: Activity on a Li-rich giant: DI Psc revisited

abstract:
  We present a new Doppler imaging study for the Li-rich single K-giant DI Psc.
Surface temperature maps are reconstructed for two subsequent rotation cycles.
From the time evolution of the spot distribution antisolar-type differential
rotation pattern is revealed. We show marks of non-uniform Li-abundance as
well. The possible connection between the current evolutionary phase of the
star and its magnetic activity is briefly discussed.


title: Maximum independent sets on random regular graphs

abstract:
  We determine the asymptotics of the independence number of the random
$d$-regular graph for all $d \ge d_0$. It is highly concentrated, with
constant-order fluctuations around $n\alpha_* - c_*\log n$ for explicit
constants $\alpha_*(d)$ and $c_*(d)$. Our proof rigorously confirms the
one-step replica symmetry breaking heuristics for this problem, and we believe
the techniques will be more broadly applicable to the study of other
combinatorial properties of random graphs.


title: Topo-Groups and a Tychonoff Type Theorem

abstract:
  In this article, we introduce an interesting topology-like concept concerning
groups (and with almost the same method it can be defined for other algebraic
systems). Given an arbitrary group $G$, we define a {\em topo-system} on $G$ as
a set of subgroups satisfying certain conditions like a topology on a set. We
will call such a group, a {\em topo-group}. These topo-groups are not rare and
as we will see, there are many examples of topo-groups. We investigate
fundamental notions concerning topo-groups and we see that many basic concepts
of topology can be introduced in the frame of topo-groups. A {\em filter of
subgroups} will be defined in such way that we will be able to formulate a
Tychonoff type theorem for the direct product of {\em topo-compact}
topo-groups.


title:
Designing heavy metal oxide glasses with threshold properties from
  network rigidity

abstract:
  Here we show that a new class of glasses composed of heavy metal oxides
involving transition metals (V$_\text {2}$O$_\text{}$5-TeO$_\text{2}$), can
surprisingly be designed from very basic tools using topology and rigidity of
their underlying molecular networks. When investigated as a function of
composition, such glasses display abrupt changes in network packing and
enthalpy of relaxation at Tg, underscoring presence of flexible to rigid
elastic phase transitions. We find that these elastic phases are fully
consistent with polaronic nature of electronic conductivity at high
V$_\text{2}$O$_\text{5}$ content. Such observations have new implications for
designing electronic glasses which differ from the traditional amorphous
electrolytes having only mobile ions as charge carriers.


title:
Dissociation and annihilation of multipartite entanglement structure in
  dissipative quantum dynamics

abstract:
  We study the dynamics of the entanglement structure of a multipartite system
experiencing a dissipative evolution. We characterize the processes leading to
a particular form of output system entanglement and provide a recipe for their
identification via concatenations of particular linear maps with
entanglement-breaking operations. We illustrate the applicability of our
approach by considering local and global depolarizing noises acting on general
multiqubit states. A difference in the typical entanglement behavior of systems
subjected to these noises is observed: the originally genuine entanglement
dissociates by splitting off particles one by one in the case of local noise,
whereas intermediate stages of entanglement clustering are present in the case
of global noise. We also analyze the definitive phase of evolution when the
annihilation of the entanglement compound finally takes place.


title:
The principal indecomposable modules of the dilute Temperley-Lieb
  algebra

abstract:
  The Temperley-Lieb algebra \tln(\beta) can be defined as the set of
rectangular diagrams with n points on each of their vertical sides, with all
points joined pairwise by non-intersecting strings. The multiplication is then
the concatenation of diagrams. The dilute Temperley-Lieb algebra \dtl n(\beta)
has a similar diagrammatic definition where, now, points on the sides may
remain free of strings. Like \tl n, the dilute \dtl n depends on a parameter
\beta\in\mathbb C, often given as \beta=q+q^{-1} for some q\in\mathbb C^\times.
In statistical physics, the algebra plays a central role in the study of dilute
loop models. The paper is devoted to the construction of its principal
indecomposable modules.
  Basic definitions and properties are first given: the dimension of \dtl n,
its break up into even and odd subalgebras and its filtration through n+1
ideals. The standard modules \U{n,k} are then introduced and their behaviour
under restriction and induction is described. A bilinear form, the Gram
product, is used to identify their (unique) maximal submodule \dr{n,k} which is
then shown to be irreducible or trivial. It is then noted that \dtl n is a
cellular algebra. This fact allows for the identification of complete sets of
non-isomorphic irreducible modules and projective indecomposable ones. The
structure of \dtl n as a left module over itself is then given for all values
of the parameter q, that is, for both q generic and a root of unity.


title:
A latent factor model with a mixture of sparse and dense factors to
  model gene expression data with confounding effects

abstract:
  One important problem in genome science is to determine sets of co-regulated
genes based on measurements of gene expression levels across samples, where the
quantification of expression levels includes substantial technical and
biological noise. To address this problem, we developed a Bayesian sparse
latent factor model that uses a three parameter beta prior to flexibly model
shrinkage in the loading matrix. By applying three layers of shrinkage to the
loading matrix (global, factor-specific, and element-wise), this model has
non-parametric properties in that it estimates the appropriate number of
factors from the data. We added a two-component mixture to model each factor
loading as being generated from either a sparse or a dense mixture component;
this allows dense factors that capture confounding noise, and sparse factors
that capture local gene interactions. We developed two statistics to quantify
the stability of the recovered matrices for both sparse and dense matrices. We
tested our model on simulated data and found that we successfully recovered the
true latent structure as compared to related models. We applied our model to a
large gene expression study and found that we recovered known covariates and
small groups of co-regulated genes. We validated these gene subsets by testing
for associations between genotype data and these latent factors, and we found a
substantial number of biologically important genetic regulators for the
recovered gene subsets.


title: Centrality categorization for R_{p(d)+A} in high-energy collisions

abstract:
  High-energy proton- and deuteron-nucleus collisions provide an excellent tool
for studying a wide array of physics effects, including modifications of parton
distribution functions in nuclei, gluon saturation, and color neutralization
and hadronization in a nuclear environment, among others. All of these effects
are expected to have a significant dependence on the size of the nuclear target
and the impact parameter of the collision, also known as the collision
centrality. In this article, we detail a method for determining centrality
classes in p(d)+A collisions via cuts on the multiplicity at backward rapidity
(i.e., the nucleus-going direction) and for determining systematic
uncertainties in this procedure. For d+Au collisions at sqrt(s_NN) = 200 GeV we
find that the connection to geometry is confirmed by measuring the fraction of
events in which a neutron from the deuteron does not interact with the nucleus.
As an application, we consider the nuclear modification factors R_{p(d)+A}, for
which there is a potential bias in the measured centrality dependent yields due
to auto-correlations between the process of interest and the backward rapidity
multiplicity. We determine the bias correction factor within this framework.
This method is further tested using the HIJING Monte Carlo generator. We find
that for d+Au collisions at sqrt(s_NN)=200 GeV, these bias corrections are
small and vary by less than 5% (10%) up to p_T = 10 (20) GeV. In contrast, for
p+Pb collisions at sqrt(s_NN) = 5.02 TeV we find these bias factors are an
order of magnitude larger and strongly p_T dependent, likely due to the larger
effect of multi-parton interactions.


title: The Gaussian Radon Transform and Machine Learning

abstract:
  There has been growing recent interest in probabilistic interpretations of
kernel-based methods as well as learning in Banach spaces. The absence of a
useful Lebesgue measure on an infinite-dimensional reproducing kernel Hilbert
space is a serious obstacle for such stochastic models. We propose an
estimation model for the ridge regression problem within the framework of
abstract Wiener spaces and show how the support vector machine solution to such
problems can be interpreted in terms of the Gaussian Radon transform.


title: Chimera: A hybrid approach to numerical loop quantum cosmology

abstract:
  The existence of a quantum bounce in isotropic spacetimes is a key result in
loop quantum cosmology (LQC), which has been demonstrated to arise in all the
models studied so far. In most of the models, the bounce has been studied using
numerical simulations involving states which are sharply peaked and which
bounce at volumes much larger than the Planck volume. An important issue is to
confirm the existence of the bounce for states which have a wide spread, or
which bounce closer to the Planck volume. Numerical simulations with such
states demand large computational domains, making them very expensive and
practically infeasible with the techniques which have been implemented so far.
To overcome these difficulties, we present an efficient hybrid numerical scheme
using the property that at the small spacetime curvature, the quantum
Hamiltonian constraint in LQC, which is a difference equation with uniform
discretization in volume, can be approximated by a Wheeler-DeWitt differential
equation. By carefully choosing a hybrid spatial grid allowing the use of
partial differential equations at large volumes, and with a simple change of
geometrical coordinate, we obtain a surprising reduction in the computational
cost. This scheme enables us to explore regimes which were so far unachievable
for the isotropic model in LQC. Our approach also promises to significantly
reduce the computational cost for numerical simulations in anisotropic LQC
using high performance computing.


title: A Near-Infrared Transmission Spectrum for the Warm Saturn HAT-P-12b

abstract:
  We present a HST WFC3 transmission spectrum for the transiting exoplanet
HAT-P-12b. This warm (1000 K) sub-Saturn-mass planet has a smaller mass and a
lower temperature than the hot-Jupiters that have been studied so far. We find
that the planet's measured transmission spectrum lacks the expected water
absorption feature for a hydrogen-dominated atmosphere, and is instead
best-described by a model with high-altitude clouds. Using a frequentist
hypothesis testing procedure, we can rule out a hydrogen-dominated cloud free
atmosphere to 4.9$\sigma$. When combined with other recent WFC3 studies, our
observations suggest that clouds may be common in exo-planetary atmospheres.


title:
Homotopy automorphisms of R-module bundles, and the K-theory of string
  topology

abstract:
  Let $R$ be a ring spectrum and $ E\to X$ an $R$-module bundle of rank $n$.
Our main result is to identify the homotopy type of the group-like monoid of
homotopy automorphisms of this bundle, $hAut^R(E)$. This will generalize the
result regarding $R$-line bundles previously proven by the authors. The main
application is the calculation of the homotopy type of $BGL_n(End ((L))$ where
$L \to X$ is any $R$-line bundle, and $End (L)$ is the ring spectrum of
endomorphisms. In the case when such a bundle is the fiberwise suspension
spectrum of a principal bundle over a manifold, $G \to P \to M$, this leads to
a description of the $K$-theory of the string topology spectrum in terms of the
mapping space from $M$ to $BGL (\Sigma^\infty (G_+))$.


title:
Broken discrete and continuous symmetries in two dimensional spiral
  antiferromagnets

abstract:
  We study the occurrence of symmetry breakings, at zero and finite
temperatures, in the J_1-J_3 antiferromagnetic Heisenberg model on the square
lattice using Schwinger boson mean field theory. For spin-1/2 the ground state
breaks always the SU(2) symmetry with a continuous quasi-critical transition at
J_3/J_1=0.38, from N\'eel to spiral long range order, although local spin
fluctuations considerations suggest an intermediate disordered regime around
0.35 < J_3/J_1 < 0.5, in qualitative agreement with recent numerical results.
At low temperatures we find a Z_2 broken symmetry region with short range
spiral order characterized by an Ising-like nematic order parameter that
compares qualitatively well with classical Monte Carlo results. At intermediate
temperatures the phase diagram shows regions with collinear short range orders:
for J_3/J_1<1 N\'eel (\pi,\pi) correlations and for J_3/J_1>1 a novel phase
consisting of four decoupled third neighbour sublattices with N\'eel (\pi,\pi)
correlations in each one. We conclude that the effect of quantum and thermal
fluctuations is to favour collinear correlations even in the strongly
frustrated regime.


title:
Small scale creation for solutions of the incompressible two dimensional
  Euler equation

abstract:
  We construct an initial data for two-dimensional Euler equation in a disk for
which the gradient of vorticity exhibits double exponential growth in time for
all times. This estimate is known to be sharp - the double exponential growth
is the fastest possible growth rate.


title:
A Gamma convergence approach to the critical Sobolev embedding in
  variable exponent spaces

abstract:
  In this paper, we study the critical Sobolev embeddings
$W^{1,p(x)}(\Omega)\subset L^{p^*(x)}(\Omega)$ for variable exponent Sobolev
spaces from the point of view of the $\Gamma$-convergence. More precisely we
determine the $\Gamma$-limit of subcritical approximation of the best constant
associated with this embedding. As an application we provide a sufficient
condition for the existence of extremals for the best constant.


title:
Multi-wavelength study of triggered star formation around 25 H II
  regions

abstract:
  We have investigated 25 H II regions with bubble morphology in 13CO(1-0) and
infrared data, to search the quantitative evidence for the triggering star
formation by collect and collapse (CC) and radiatively driven implosion (RDI)
models. These H II regions display the morphology of the complete or partial
bubble at 8 um, which all are associated with the surrounding molecular clouds.
We obtained that the electron temperature ranges from 5627 K to 6839 K in these
H II regions, and the averaged electron temperature is 6083 K. The age of these
H II regions is from 3.0\times10^{5} yr to 1.7\times10^{6} yr, and the mean age
is 7.7\times10^{5} yr. Based on the morphology of the associated molecular
clouds, we divided these H II regions into three groups, which may support CC
and RDI models. We selected 23 young IRAS sources with the infrared luminosity
of >10^{3}L_{\odot} in 19 H II regions. In addition, we identified some young
stellar objects (including Class I sources), which are concentrated only in H
II regions G29.007+0.076, G44.339-0.827, and G47.028+0.232. The polycyclic
aromatic hydrocarbons (PAHs) emission of the three H II regions all show the
cometary globule. Comparing the age of each H II region with the characteristic
timescales for star formation, we suggest that the three H II regions can
trigger the clustered star formation by RDI process. In addition, we for the
first time detected seven molecular outflows in the five H II regions. These
outflow sources may be triggered by the corresponding H II regions.


title: On Demand Memory Specialization for Distributed Graph Databases

abstract:
  In this paper, we propose the DN-tree that is a data structure to build lossy
summaries of the frequent data access patterns of the queries in a distributed
graph data management system. These compact representations allow us an
efficient communication of the data structure in distributed systems. We
exploit this data structure with a new \textit{Dynamic Data Partitioning}
strategy (DYDAP) that assigns the portions of the graph according to historical
data access patterns, and guarantees a small network communication and a
computational load balance in distributed graph queries. This method is able to
adapt dynamically to new workloads and evolve when the query distribution
changes. Our experiments show that DYDAP yields a throughput up to an order of
magnitude higher than previous methods based on cache specialization, in a
variety of scenarios, and the average response time of the system is divided by
two.


title: Sliding drops across alternating hydrophobic and hydrophilic stripes

abstract:
  We perform a joint numerical and experimental study to sistematically
characterize the motion of drops sliding over a periodic array of alternating
hydrophobic and hydrophilic stripes with large wettability contrast, and
typical width of hundreds of $\mu \textrm{m}$. The fraction of the hydrophobic
stripes has been varied from about 20% to 80%. The effects of the heterogeneous
patterning can be described by a renormalized value of the critical Bond
number, i.e. the critical dimensionless force needed to depin the drop before
it starts to move. Close to the critical Bond number we observe a jerkily
motion characterized by an evident stick-slip dynamics. As a result,
dissipation is strongly localized in time, and the mean velocity of the drops
can easily decrease by an order of magnitude compared to the sliding on
homogeneous surface. Lattice Boltzmann (LB) numerical simulations are crucial
for disclosing to what extent the sliding dynamics can be deduced from the
computed balance of capillary, viscous and body forces at varying the Bond
number, the surface composition and the liquid viscosity. Away from the
critical Bond number, we characterize both experimentally and numerically the
dissipation inside the droplet by studying the relation between the average
velocity and the applied volume forces.


title:
PPAK Wide field Integral Field Spectroscopy of NGC 628 III. Stellar
  population properties

abstract:
  We present a stellar population analysis of the nearby, face-on, SA(s)c
galaxy, NGC628, which is part of the PPAK IFS Nearby Galaxies Survey (PINGS).
The data cover a field of view of ~6 arcmin in diameter with a sampling of
$\sim$2.7 arcsec per spectrum and a wavelength range (3700-7000A). We apply
spectral inversion methods to derive 2-dimensional maps of star formation
histories and chemical enrichment. We present maps of the mean (luminosity- and
mass-weighted) age and metallicity that reveal the presence of structures such
as a nuclear ring, previously seen in molecular gas. The disk is dominated in
mass by an old stellar component at all radii sampled by our data, while the
percentage of young stars increase with radius. The mean stellar age and
metallicity profiles have a two defined regions, an inner one with flatter
gradients (even slightly positive) and an external ones with a negative,
steeper one, separated at $\sim$60 arcsec. This break in the profiles is more
prominent in the old stellar component. The young component shows a metallicity
gradient that is very similar to that of the gas, and that is flatter in the
whole disc. The agreement between the metallicity gradient of the young stars
and the gas, and the recovery of the measured colours from our derived star
formation histories validate the techniques to recover the age-metallicity and
the star formation histories in disc galaxies from integrated spectra. We
speculate about the possible origin of the break and conclude that the most
likely scenario is that we are seeing, in the center of NGC 628, a dissolving
bar, as predicted in some numerical simulations.


title:
Efficient and realistic device modeling from atomic detail to the
  nanoscale

abstract:
  As semiconductor devices scale to new dimensions, the materials and designs
become more dependent on atomic details. NEMO5 is a nanoelectronics modeling
package designed for comprehending the critical multi-scale, multi-physics
phenomena through efficient computational approaches and quantitatively
modeling new generations of nanoelectronic devices as well as predicting novel
device architectures and phenomena. This article seeks to provide updates on
the current status of the tool and new functionality, including advances in
quantum transport simulations and with materials such as metals, topological
insulators, and piezoelectrics.


title: Bounded cohomology via partial differential equations, I

abstract:
  We present a new technique that employs partial differential equations in
order to explicitly construct primitives in the continuous bounded cohomology
of Lie groups. As an application, we prove a vanishing theorem for the
continuous bounded cohomology of SL(2, R) in degree four, establishing a
special case of a conjecture of Monod.


title: High-order algorithms for solving eigenproblems over discrete surfaces

abstract:
  The eigenvalue problem of the Laplace-Beltrami operators on curved surfaces
plays an essential role in the convergence analysis of the numerical
simulations of some important geometric partial differential equations which
involve this operator. In this note we shall combine the local tangential
lifting (LTL) method with the configuration equation to develop a new effective
and convergent algorithm to solve the eigenvalue problems of the
Laplace-Beltrami operators acting on functions over discrete surfaces. The
convergence rates of our algorithms of discrete Laplace-Beltrami operators over
surfaces is $O(r^n)$, $n \geq 1$, where $r$ represents the size of the mesh of
discretization of the surface. The problem of high-order accuracies will also
be discussed and used to compute geometric invariants of the underlying
surfaces. Some convergence tests and eigenvalue computations on the sphere,
tori and a dumbbell are presented.


title:
Confined states in quantum dots defined within finite flakes of bilayer
  graphene: Coupling to the edge, ionization threshold, and valley degeneracy

abstract:
  We study quantum dots defined by external potentials within finite flakes of
bilayer graphene using the tight-binding approach. We find that in the limit of
large flakes containing zigzag edges the dot-localized energy levels appear
within the energy continuum formed by extended states. As a consequence no
ionization threshold for the carriers contained within the dot exists. For
smaller flakes with zigzag boundaries the dot-localized energy levels appear
interlaced with the energy levels outside the flake, so in a charging
experiment the electrons will be added alternately to the dot area and to its
neighborhood. We demonstrate that for flakes with armchair boundaries only, an
energy window accessible uniquely to the dot-localized states is opened. Then a
number of electrons can be added to the dot before the external states start to
be occupied. We also discuss coupling of the dot-localized states to the edge
states in the context of the valley degeneracy lifting. Moreover, we extract
smooth envelope wave functions from the tight-binding solution and discuss
their spatial symmetries. The coupling of the dot localized energy levels with
reconstructed zigzag edges and atomic vacancies present within the layers is
also considered.


title:
Small-energy analysis for the selfadjoint matrix Schroedinger operator
  on the half line. II

abstract:
  The matrix Schroedinger equation with a selfadjoint matrix potential is
considered on the half line with the most general selfadjoint boundary
condition at the origin. When the matrix potential is integrable and has a
second moment, it is shown that the corresponding scattering matrix is
differentiable at zero energy. An explicit formula is provided for the
derivative of the scattering matrix at zero energy. The previously established
results when the potential has only the first moment are improved when the
second moment exists, by presenting the small-energy asymptotics for the
related Jost matrix, its inverse, and various other quantities relevantc to the
corresponding direct and inverse scattering problems.


title: The first law of soliton and black hole mechanics in five dimensions

abstract:
  We derive a mass formula and a mass variation law for asymptotically flat,
stationary spacetimes, invariant under two commuting rotational symmetries, in
a general five dimensional theory of gravity coupled to an arbitrary set of
Maxwell fields and uncharged scalar fields. If the spacetime is everywhere
regular, these mass formulas reduce to a sum of magnetic flux terms defined on
its non-trivial 2-cycles. If there is a black hole, we obtain a mass variation
law more general than previously obtained, which also has contributions from
the 2-cycles exterior to the black hole. This can be interpreted as the first
law of black hole mechanics in a background soliton containing bubbles.


title: Entanglement dynamics in a system attached to self-interacting spinbaths

abstract:
  Dynamics of quantum entanglement shared between system spins which are
connected to thermal equilibrium baths is studied. Central spin system
comprises of the entangled spins, and is connected to baths and one of the bath
has strong intra-environmental coupling. The dynamics between the system and
baths are studied and inferred that that intra-envirnomental coupling guards
against the system from the effects of the spin baths.


title:
Equivariant Gromov-Witten Theory of Affine Smooth Toric Deligne-Mumford
  Stacks

abstract:
  For any finite abelian group G, the equivariant Gromov-Witten invariants of
C^r/G can be viewed as a certain kind of abelian Hurwitz-Hodge integrals. In
this note, we use Tseng's orbifold quantum Riemann-Roch theorem to express this
kind of abelian Hurwitz-Hodge integrals as a sum over Feynman graphs, where the
weight of each graph is expressed in terms of descendant integrals over moduli
spaces of stable curves and representations of G. This expression will play a
crucial role in the proof of the remodeling conjecture (arXiv:0709.1453,
arXiv:0807.0597) for affine toric Calabi-Yau 3-orbifolds in arXiv:1310.4818.


title: The Kramers problem for Holway-Shakhov equation

abstract:
  The analytical solution of a problem on isothermal sliding of rarefied gas
along a flat firm surface (the Kramers problem) for Holway-Shakhov equation is
presented.


title: Water Filtration Using Plant Xylem

abstract:
  Effective point-of-use devices for providing safe drinking water are urgently
needed to reduce the global burden of waterborne disease. Here we show that
plant xylem from the sapwood of coniferous trees - a readily available,
inexpensive, biodegradable, and disposable material - can remove bacteria from
water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can
filter water at the rate of several liters per day, sufficient to meet the
clean drinking water needs of one person. The results demonstrate the potential
of plant xylem to address the need for pathogen-free drinking water in
developing countries and resource-limited settings.


title:
Propagation of a squeezed optical field in a medium with superluminal
  group velocity

abstract:
  We investigated the propagation of a squeezed optical field, generated via
the polarization self-rotation (PSR) effect, with a sinusoidally-modulated
degree of squeezing through an atomic medium with anomalous dispersion. We
observed the advancement of the signal propagating through a resonant Rb vapor
compared to the reference signal, propagating in air. The measured advancement
time grew linearly with atomic density, reaching a maximum of $11 \pm 1~\mu$s,
which corresponded to a negative group velocity of $v_g\approx - 7,000~$m/s. We
also confirmed that the increasing advancement was accompanied by a reduction
of output squeezing levels due to optical losses, in good agreement with
theoretical predictions.


title:
Small mass asymptotics of a charged particle in a variable magnetic
  field

abstract:
  We consider small mass asymptotics of the motion of a charged particle in a
noisy force field combined with a variable magnetic field. The
Smoluchowski-Kramers approximation does not hold in this case. We show that
after a regularization of noise, a Smoluchowski-Kramers type approximation
works.


title:
Double neutron spin resonances and gap anisotropy in underdoped
  superconducting NaFe0.985Co0.015As

abstract:
  We use inelastic neutron scattering to show that superconductivity in
electron-underdoped NaFe0.985Co0.015As induces a dispersive sharp resonance
near Er1 = 3:25 meV and a broad dis- persionless mode at Er2 = 6 meV. However,
similar measurements on overdoped superconducting NaFe0:955Co0:045As find only
a single sharp resonance at Er = 7 meV. We connect these results with the
observations of angle-resolved photoemission spectroscopy that the
superconducting gaps in the electron Fermi pockets are anisotropic in the
underdoped material but become isotropic in the overdoped case. Our analysis
indicates that both the double neutron spin resonances and gap anisotropy
originate from the orbital dependence of the superconducting pairing in the
iron pnic- tides. Our discovery also shows the importance of the inelastic
neutron scattering in detecting the multiorbital superconducting gap structures
of iron pnictides.


title:
All Genus Open-Closed Mirror Symmetry for Affine Toric Calabi-Yau
  3-Orbifolds

abstract:
  The Remodeling Conjecture proposed by Bouchard-Klemm-Marino-Pasquetti
[arXiv:0709.1453, arXiv:0807.0597] relates all genus open and closed
Gromov-Witten invariants of a semi-projective toric Calabi-Yau
3-manifolds/3-orbifolds to the Eynard-Orantin invariants of the mirror curve of
the toric Calabi-Yau 3-fold. In this paper, we present a proof of the
Remodeling Conjecture for open-closed orbifold Gromov-Witten invariants of an
arbitrary affine toric Calabi-Yau 3-orbifold relative to a framed Aganagic-Vafa
Lagrangian brane. This can be viewed as an all genus open-closed mirror
symmetry for affine toric Calabi-Yau 3-orbifolds.


title:
Considerations on Gravitational Effects Stimulated by Gravitational
  Fields via Classical Field Theory

abstract:
  A mass distribution is analyzed in terms of classical gravitational field
theory. Newton's law of gravitation is consistently applied on the assumption
that the equivalence of energy and mass according to Einstein's theory of
relativity is valid for gravitational fields as well. Different from standard
approaches the gravitational field, via its associated field energy, is handled
as a source of gravitation by itself. Starting from these principles a
gravitational self-shielding phenomenon is derived as a common characteristic
of all mass/energy distributions. Moreover, it is demonstrated that even in the
absence of any stimulating mass the existence of independent static
gravitational fields is fully consistent with Newton's law of gravitation as
long as the equivalence of energy and mass is respected. From a distance such
gravitational fields appear as negative masses.


title:
Two Weight Inequalities for the Cauchy Transform from $ \mathbb{R}$ to $
  \mathbb{C}_+$

abstract:
  We characterize those pairs of weights $ \sigma $ on $ \mathbb{R}$ and $ \tau
$ on $ \mathbb{C}_+$ for which the Cauchy transform $\mathsf{C}_{\sigma} f (z)
\equiv \int_{\mathbb{R}} \frac {f(x)} {x-z} \; \sigma (dx)$, $ z\in
\mathbb{C}_+$, is bounded from $L ^2(\mathbb{R};\sigma)$ to $L
^{2}(\mathbb{C}_+; \tau)$. The characterization is in terms of an $A_2$
condition on the pair of weights and testing conditions for the transform,
extending the recent solution of the two weight inequality for the Hilbert
transform. As corollaries of this result we derive (1) a characterization of
embedding measures for the model space $K_\vartheta$, for arbitrary inner
function $ \vartheta $, and (2) a characterization of the (essential) norm of
composition operators mapping $K_\vartheta$ into a general class of Hardy and
Bergman spaces.


title: Ising Spectroscopy II: Particles and poles at T>Tc

abstract:
  I discuss particle content of the Ising field theory (the scaling limit of
the Ising model in a magnetic field), in particular the evolution of its mass
spectrum under the change of the scaling parameter. I consider both real and
pure imaginary magnetic field. Here I address the high-temperature regime,
where the spectrum of stable particles is relatively simple (there are from one
to three particles, depending on the parameter). My goal is to understand
analytic continuations of the masses to the domain of the parameter where they
no longer exist as the stable particles. I use the natural tool -- the $2\to 2$
elastic scattering amplitude, with its poles associated with the stable
particles, virtual and resonance states in a standard manner. Concentrating
attention on the "real" poles (those corresponding to stable and virtual
states) I propose a scenario on how the pattern of the poles evolves from the
integrable point $T=T_c,\ H\neq 0$ to the free particle point $T>T_c,\ H=0$,
and then, along the pure imaginary $H$, to the Yang-Lee critical point.
Waypoints along this evolution path are located using TFFSA data. I also
speculate about likely behavior of some of the resonance poles.


title:
Principal motion components for gesture recognition using a
  single-example

abstract:
  This paper introduces principal motion components (PMC), a new method for
one-shot gesture recognition. In the considered scenario a single
training-video is available for each gesture to be recognized, which limits the
application of traditional techniques (e.g., HMMs). In PMC, a 2D map of motion
energy is obtained per each pair of consecutive frames in a video. Motion maps
associated to a video are processed to obtain a PCA model, which is used for
recognition under a reconstruction-error approach. The main benefits of the
proposed approach are its simplicity, easiness of implementation, competitive
performance and efficiency. We report experimental results in one-shot gesture
recognition using the ChaLearn Gesture Dataset; a benchmark comprising more
than 50,000 gestures, recorded as both RGB and depth video with a Kinect
camera. Results obtained with PMC are competitive with alternative methods
proposed for the same data set.


title: G2C2 I: Homogeneous SDSS photometry for Galactic GCs

abstract:
  We present $g^\prime$ and $z^\prime$ aperture photometry for 96 Galactic
Globular Clusters, making this the largest homogeneous catalog of photometry
for these objects in the SDSS filter system. For a subset of 56 clusters we
also provide photometry in $r^\prime$ and $i^\prime$. We carry out comparisons
with previous photometry as well as with the SDSS dataset. The data will be
useful for a series of applications in Galactic and extragalactic astrophysics.
Future papers will analyse the colour-metallicity relation, colour-magnitude
diagrams, and structural parameters. The compilation of results based on this
dataset will be collected in the Galactic Globular Cluster Catalog (G2C2).


title: A Tidally-Stripped Stellar Component of the Magellanic Bridge

abstract:
  Deep photometry of the Small Magellanic Cloud (SMC) stellar periphery (R=4
deg, 4.2 kpc) is used to study its line-of-sight depth with red clump (RC)
stars. The RC luminosity function is affected little by young (<1 Gyr)
blue-loop stars in these regions because their main-sequence counterparts are
not observed in the color magnitude diagrams. The SMC's eastern side is found
to have a large line-of-sight depth (~23 kpc) while the western side has a much
shallower depth (~10 kpc), consistent with previous photographic plate
photometry results. We use a model SMC RC luminosity function to deconvolve the
observed RC magnitudes and construct the density function in distance for our
fields. Three of the eastern fields show a distance bimodality with one
component at the "systemic" ~67 kpc SMC distance and a second component at ~55
kpc. Our data are not reproduced well by the various extant Magellanic Cloud
and Stream simulations. However, the models predict that the known HI
Magellanic Bridge (stretching from the SMC eastward towards the LMC) has a
decreasing distance with angle from the SMC and should be seen in both the
gaseous and stellar components. From comparison with these models we conclude
that the most likely explanation for our newly identified ~55 kpc stellar
structure in the eastern SMC is a stellar counterpart of the HI Magellanic
Bridge that was tidally stripped from the SMC ~200 Myr ago during a close
encounter with the LMC. This discovery has important implications for
microlensing surveys of the SMC.


title:
Direct Imaging and Spectroscopy of a Candidate Companion Below/Near the
  Deuterium-Burning Limit In The Young Binary Star System, ROXs 42B

abstract:
  We present near-infrared high-contrast imaging photometry and integral field
spectroscopy of ROXs 42B, a binary M0 member of the 1--3 Myr-old $\rho$
Ophiuchus star-forming region, from data collected over 7 years. Each data set
reveals a faint companion -- ROXs 42Bb -- located $\sim$ 1.16" ($r_{proj}$
$\approx$ 150 $AU$) from the primaries at a position angle consistent with a
point source identified earlier by Ratzka et al. (2005). ROXs 42Bb's astrometry
is inconsistent with a background star but consistent with a bound companion,
possibly one with detected orbital motion. The most recent data set reveals a
second candidate companion at $\sim$ 0.5" of roughly equal brightness, though
preliminary analysis indicates it is a background object. ROXs 42Bb's $H$ and
$K_{s}$ band photometry is similar to dusty/cloudy young, low-mass late M/early
L dwarfs. $K$-band VLT/SINFONI spectroscopy shows ROXs 42Bb to be a cool
substellar object (M8--L0; $T_{eff}$ $\approx$ 1800--2600 $K$), not a
background dwarf star, with a spectral shape indicative of young, low surface
gravity planet-mass companions. We estimate ROXs 42Bb's mass to be 6--15
$M_{J}$, either below the deuterium burning limit and thus planet mass or
straddling the deuterium-burning limit nominally separating planet-mass
companions from other substellar objects. Given ROXs 42b's projected separation
and mass with respect to the primaries, it may represent the lowest mass
objects formed like binary stars or a class of planet-mass objects formed by
protostellar disk fragmentation/disk instability, the latter slightly blurring
the distinction between non-deuterium burning planets like HR 8799 bcde and
low-mass, deuterium-burning brown dwarfs.


title:
Search for CP Violating Signature of Intergalactic Magnetic Helicity in
  the Gamma Ray Sky

abstract:
  The existence of a cosmological magnetic field could be revealed by the
effects of non-trivial helicity on large scales. We evaluate a CP odd
statistic, $Q$, using gamma ray data obtained from Fermi satellite observations
at high galactic latitudes to search for such a signature. Observed values of
$Q$ are found to be non-zero; the probability of a similar signal in Monte
Carlo simulations is $\sim 0.2\%$. Contamination from the Milky Way does not
seem to be responsible for the signal since it is present even for data at very
high galactic latitudes. Assuming that the signal is indeed due to a helical
cosmological magnetic field, our results indicate left-handed magnetic helicity
and field strength $\sim 10^{-14}~{\rm G}$ on $\sim 10~{\rm Mpc}$ scales.


title: Super-Razor and Searches for Sleptons and Charginos at the LHC

abstract:
  Direct searches for electroweak pair production of new particles at the LHC
are a difficult proposition, due to the large background and low signal cross
sections. We demonstrate how these searches can be improved by a combination of
new razor variables and shape analysis of signal and background kinematics. We
assume that the pair-produced particles decay to charged leptons and missing
energy, either directly or through a W boson. In both cases the final state is
a pair of opposite sign leptons plus missing transverse energy. We estimate
exclusion reach in terms of sleptons and charginos as realized in minimal
supersymmetry. We compare this super-razor approach in detail to analyses based
on other kinematic variables, showing how the super-razor uses more of the
relevant kinematic information while achieving higher selection efficiency on
signals, including cases with compressed spectra.


title: Gluon-initiated associated production boosts Higgs physics

abstract:
  Analyses of boosted Higgs bosons from associated production comprise some of
the main search channels for the Higgs boson at the LHC. The gluon-initiated
$gg\to hZ$ subprocess has largely been ignored in phenomenological analyses of
boosted associated production although this contribution is sizable as the
$p_T$ spectrum for this process is maximised in the boosted regime due to the
top quark loop threshold. In this paper, we discuss this contribution to
boosted $pp\to hZ$ analyses in detail. We find there are previously overlooked
modifications of Standard Model Higgs rates at the LHC which depend on the
$p_T$ cuts applied and can be significant. There are also important
consequences for physics beyond the Standard Model as the $gg\to hZ$ process
introduces significant dependence on the magnitude and sign of the Higgs-top
quark coupling $c_t$, which is overlooked if it is assumed that associated
production depends only on the Higgs-$Z$ boson coupling as $c_V^2$. This new
dependence on $c_t$ impacts interpretations of Higgs rates in the contexts of
Supersymmetry, Two Higgs Doublet Models, and general scenarios with modified
couplings. We suggest that these effects be included in current and future LHC
boosted Higgs analyses.


title:
G2C2 II: Integrated colour-metallicity relations for Galactic Globular
  Clusters in SDSS passbands

abstract:
  We use our integrated SDSS photometry for 96 globular clusters in $g$ and
$z$, as well as $r$ and $i$ photometry for a subset of 56 clusters, to derive
the integrated colour-metallicity relation (CMR) for Galactic globular
clusters. We compare this relation to previous work, including extragalactic
clusters, and examine the influence of age, present-day mass function
variations, structural parameters and the morphology of the horizontal branch
on the relation. Moreover, we scrutinise the scatter introduced by foreground
extinction (including differential reddening) and show that the scatter in the
colour-metallicity relation can be significantly reduced combining two
reddening laws from the literature. In all CMRs we find some low-reddening
young GCs that are offset to the CMR. Most of these outliers are associated
with the Sagittarius system. Simulations show that this is due less to age than
to a different enrichment history. Finally, we introduce colour-metallicity
relations based on the infrared Calcium triplet, which are clearly non-linear
when compared to $(g^\prime-i^\prime)$ and $(g^\prime-z^\prime)$ colours.


title: Strong Lens Time Delay Challenge: I. Experimental Design

abstract:
  The time delays between point-like images in gravitational lens systems can
be used to measure cosmological parameters. The number of lenses with measured
time delays is growing rapidly; the upcoming \emph{Large Synoptic Survey
Telescope} (LSST) will monitor $\sim10^3$ strongly lensed quasars. In an effort
to assess the present capabilities of the community to accurately measure the
time delays, and to provide input to dedicated monitoring campaigns and future
LSST cosmology feasibility studies, we have invited the community to take part
in a "Time Delay Challenge" (TDC). The challenge is organized as a set of
"ladders," each containing a group of simulated datasets to be analyzed blindly
by participating teams. Each rung on a ladder consists of a set of realistic
mock observed lensed quasar light curves, with the rungs' datasets increasing
in complexity and realism. The initial challenge described here has two
ladders, TDC0 and TDC1. TDC0 has a small number of datasets, and is designed to
be used as a practice set by the participating teams. The (non-mandatory)
deadline for completion of TDC0 was the TDC1 launch date, December 1, 2013. The
TDC1 deadline was July 1 2014. Here we give an overview of the challenge, we
introduce a set of metrics that will be used to quantify the goodness-of-fit,
efficiency, precision, and accuracy of the algorithms, and we present the
results of TDC0. Thirteen teams participated in TDC0 using 47 different
methods. Seven of those teams qualified for TDC1, which is described in the
companion paper II.


title: Passive interferometric symmetries of multimode Gaussian pure states

abstract:
  As large-scale multimode Gaussian states begin to become accessible in the
laboratory, their representation and analysis become a useful topic of research
in their own right. The graphical calculus for Gaussian pure states provides
powerful tools for their representation, while this work presents a useful tool
for their analysis: passive interferometric (i.e., number-conserving)
symmetries. Here we show that these symmetries of multimode Gaussian states
simplify calculations in measurement-based quantum computing and provide
constructive tools for engineering large-scale harmonic systems with specific
physical properties, and we provide a general mathematical framework for
deriving them. Such symmetries are generated by linear combinations of
operators expressed in the Schwinger representation of U(2), called nullifiers
because the Gaussian state in question is a zero eigenstate of them. This
general framework is shown to have applications in the noise analysis of
continuous-various cluster states and is expected to have additional
applications in future work with large-scale multimode Gaussian states.


abstract:
  The Andromeda Optical and Infrared Disk Survey has mapped M31 in $u^*
g^\prime r^\prime i^\prime J K_s$ wavelengths out to R=40 kpc using the MegaCam
and WIRCam wide-field cameras on the Canada-France-Hawaii Telescope. Our survey
is uniquely designed to simultaneously resolve stars while also carefully
reproducing the surface brightness of M31, allowing us to study M31's global
structure in the context of both resolved stellar populations and spectral
energy distributions. We use the Elixir-LSB method to calibrate the optical
$u^* g^\prime r^\prime i^\prime$ images by building real-time maps of the sky
background with sky-target nodding. These maps are stable to $\mu_g \lesssim
28.5$ mag arcsec$^{-2}$ and reveal warps in the outer M31 disk in surface
brightness. The equivalent WIRCam mapping in the near-infrared uses a
combination of sky-target nodding and image-to-image sky offset optimization to
produce stable surface brightnesses. This study enables a detailed analysis of
the systematics of spectral energy distribution fitting with near-infrared
bands where asymptotic giant branch stars impose a significant, but
ill-constrained, contribution to the near-infrared light of a galaxy. Here we
present panchromatic surface brightness maps and initial results from our
near-infrared resolved stellar catalog.


title:
Beating the classical limit: A diffraction-limited spectrograph for an
  arbitrary input beam

abstract:
  We demonstrate a new approach to classical fiber-fed spectroscopy. Our method
is to use a photonic lantern that converts an arbitrary (e.g. incoherent) input
beam into N diffraction-limited outputs. For the highest throughput, the number
of outputs must be matched to the total number of unpolarized spatial modes on
input. This approach has many advantages: (i) after the lantern, the instrument
is constructed from 'commercial off the shelf' components; (ii) the instrument
is the minimum size and mass configuration at a fixed resolving power and
spectral order (~shoebox sized in this case); (iii) the throughput is better
than 60% (slit to detector, including detector QE of ~80%); (iv) the scattered
light at the detector can be less than 0.1% (total power). Our first
implementation operates over 1545-1555 nm (limited by the detector, a
640$\times$512 array with 20$\mu$m pitch) with a spectral resolution of 0.055nm
(R~30,000) using a 1$\times$7 (1 multi-mode input to 7 single-mode outputs)
photonic lantern. This approach is a first step towards a fully integrated,
multimode photonic microspectrograph.


title:
Globular Cluster Scale Sizes in Giant Galaxies: The Case of M87 and the
  Role of Orbital Anisotropy and Tidal Filling

abstract:
  We present new Hubble Space Telescope imaging of the outer regions of M87 in
order to study its globular cluster (GC) population out to large galactocentric
distances. We discuss particularly the relationship between GC effective radii
$r_h$ and projected galactocentric distance $R_{gc}$. The observations suggest
a shallow trend $r_h \propto R_{gc}^{0.14}$ out to $R_{gc} \sim 100$ kpc, in
agreement with studies of other giant elliptical galaxies. To theoretically
reproduce this relationship we simulate GC populations with various
distributions of orbits. For an isotropic distribution of cluster orbits we
find a steeper trend of $r_h \propto R_{gc}^{0.4}$. Instead we suggest that (a)
if the cluster system has an orbital anisotropy profile, where orbits become
preferentially radial with increasing galactocentric distance, AND (b) if
clusters become more tidally under-filling with galactocentric distance, the
observed relationship can be recovered. We also apply this approach to the red
and blue GC populations separately and predict that red clusters are
preferentially under-filling at large $R_{gc}$ and have a more isotropic
distribution of orbits than blue clusters.


title:
Ly{\alpha} Equivalent Width Distribution of Ly{\alpha} Emitting Galaxies
  at Redshift z $\sim$ 4.5

abstract:
  Ly{\alpha} line EWs provide important clues to the physical nature of high
redshift LAEs. However, measuring the Ly{\alpha} EW distribution of high-z
narrowband selected LAEs can be hard because many sources do not have broadband
photometry. We investigate the possible biases in measuring the intrinsic
Ly{\alpha} EW distribution for a LAE sample at z $\sim$ 4.5 in the Extended
CDFS. Only weak Malmquist-type bias in both the intrinsic Ly{\alpha} luminosity
function and the Ly{\alpha} EW distribution were found. However, the observed
EW distribution is severely biased if one only considers LAEs with detections
in the continuum. Taking the broadband non-detections into account requires
fitting the distribution of the broadband-to-narrowband ratio, which then gives
a larger EW distribution scale length. Assuming an exponential form of the
intrinsic Ly{\alpha} EW distribution dN/dEW = N exp(-EW/W$_0$), we obtain W$_0$
= 167+/-44{\AA} (uncorrected for IGM absorption of Ly{\alpha}). We discuss the
likely range of IGM absorption effects in light of recent measurements of
Ly{\alpha} line profiles and velocity offsets. Our data are consistent with
Ly{\alpha} EW being independent of UV luminosity (i.e., we do not see evidence
for the "Ando" effect). Our simulations also imply that broad-band images
should be 0.5-1 magnitude deeper than narrowband images for an effective and
reasonably complete LAE survey. Comparing with consistent measurements at other
redshifts, we see a strong evolution in Ly{\alpha} EW distribution with
redshift which goes as a power-law form of W$_0$ $\prop$(1+z)$^${\xi}, with
{\xi} = 1.1$\pm$0.1 (0.6$\pm$0.1) if no IGM corrections are applied to the
Ly{\alpha} line; or {\xi} = 1.7$\pm$0.1 (1.2$\pm$0.1) after applying a maximal
IGM-absorption correction to Ly{\alpha} line) for an exponential (a gaussian)
EW distribution from z = 0.3 to 6.5.


title: N=1 SUSY AdS4 vacua in IIB SUGRA on group manifolds

abstract:
  We study N=1 compactification of IIB supergravity to AdS4. The internal
manifold must have SU(2)-structure. By putting some restrictions on the SU(2)
torsion classes, we can perform an exhaustive scan of all possible solutions on
group manifolds. We show that sourceless solutions don't exist and that the
presence of O5 and O7 orientifolds is mandatory. We also find a new solution
and relate it by T-duality to a known type IIA solution with O6 planes.


title:
Valence calculation of the electric polarizability on nHYP-Clover
  ensembles

abstract:
  We present preliminary calculations for the electric polarizability of the
neutral pion and neutron on three dynamically generated nHYP-Clover ensembles.
We use two different pion masses ($m_{\pi} \simeq 300$ and 220 MeV) to gauge
the chiral behavior. The effects of partial quenching are analyzed by computing
a string of partial quenched valence masses for each ensemble. We also analyzed
the volume dependence using elongated lattices, where the elongation is in the
direction of the electric field.


title:
Renormalization Group Evolution of the Standard Model Dimension Six
  Operators II: Yukawa Dependence

abstract:
  We calculate the complete order y^2 and y^4 terms of the 59 x 59 one-loop
anomalous dimension matrix for the dimension-six operators of the Standard
Model effective field theory, where y is a generic Yukawa coupling. These
terms, together with the terms of order lambda, lambda^2 and lambda y^2
depending on the Standard Model Higgs self-coupling lambda which were
calculated in a previous work, yield the complete one-loop anomalous dimension
matrix in the limit of vanishing gauge couplings. The Yukawa contributions
result in non-trivial flavor mixing in the various operator sectors of the
Standard Model effective theory.


title:
Cylindrical Beam Propagation Modelling of Perturbed Whispering-Gallery
  Mode Microcavities

abstract:
  We simulate light propagation in perturbed whispering-gallery mode
microcavities using a two-dimensional finite-difference beam prop- agation
method in a cylindrical coordinate system. Optical properties of
whispering-gallery microcavities perturbed by polystyrene nanobeads are
investigated through this formulation. The light perturbation as well as
quality factor degradation arising from cavity ellipticity are also studied.


title:
Electrical Detection of Direct and Alternating Spin Current Injected
  from a Ferromagnetic Insulator into a Ferromagnetic Metal

abstract:
  We report room temperature electrical detection of spin injection from a
ferromagnetic insulator (YIG) into a ferromagnetic metal (Permalloy, Py).
Non-equilibrium spins with both static and precessional spin polarizations are
dynamically generated by the ferromagnetic resonance of YIG magnetization, and
electrically detected by Py as dc and ac spin currents, respectively. The dc
spin current is electrically detected via the inverse spin Hall effect of Py,
while the ac spin current is converted to a dc voltage via the spin
rectification effect of Py which is resonantly enhanced by dynamic exchange
interaction between the ac spin current and the Py magnetization. Our results
reveal a new path for developing insulator spintronics, which is distinct from
the prevalent but controversial approach of using Pt as the spin current
detector.


title:
Swansong Biospheres II: The final signs of life on terrestrial planets
  near the end of their habitable lifetimes

abstract:
  The biosignatures of life on Earth do not remain static, but change
considerably over the planet's habitable lifetime. Earth's future biosphere,
much like that of the early Earth, will consist of predominantly unicellular
microorganisms due to the increased hostility of environmental conditions
caused by the Sun as it enters the late stage of its main sequence evolution.
Building on previous work, the productivity of the biosphere is evaluated
during different stages of biosphere decline between 1 Gyr and 2.8 Gyr from
present. A simple atmosphere-biosphere interaction model is used to estimate
the atmospheric biomarker gas abundances at each stage and to assess the
likelihood of remotely detecting the presence of life in low-productivity,
microbial biospheres, putting an upper limit on the lifetime of Earth's
remotely detectable biosignatures. Other potential biosignatures such as leaf
reflectance and cloud cover are discussed.


title: Dust May Be More Rare Than Expected in Metal Poor Galaxies

abstract:
  'Normal' galaxies observed at z>6, when the Universe was <1 billion years
old, thus far show no evidence of the cold dust that accompanies star formation
in the local Universe, where the dust-to-gas mass ratio is 1%. A prototypical
example is 'Himiko' (z=6.6), which a mere 840 Myr after the Big Bang is forming
stars at a rate of 30-100 Msun/yr, yielding a mass assembly time M^{star}/SFR
150x10^6 yr. Himiko is estimated to have a low fraction (2-3% of the Solar
value) of elements heavier than helium (metallicity), and although its gas mass
cannot be asserted at this time its dust-to-stellar mass ratio is constrained
to be <0.05%. The local galaxy I Zw 18, with a metallicity 4% solar and forming
stars less rapidly than Himiko but still vigorously for its mass (M^{star}/SFR
1.6x10^9 yr), is also very dust deficient and perhaps one of the best analogues
of primitive galaxies accessible to detailed study. Here we report observations
of dust emission from I Zw 18 from which we determine its dust mass to be
450-1800 Msun, yielding a dust-to-stellar mass ratio \approx 10^{-6}-10^{-5}
and a dust-to-gas mass ratio 3.2-13x10^{-6}. If I Zw 18 is a reasonable analog
of Himiko, then Himiko's dust mass is \approx 50,000 Msun, a factor of 100
below the current upper limit. These numbers are considerably uncertain, but if
most high-z galaxies are more like Himiko than like the quasar host SDSS
J114816.64+525150.3, then the prospects for detecting the gas and dust in them
are much poorer than hitherto anticipated.


title: Scalable Boolean Tensor Factorizations using Random Walks

abstract:
  Tensors are becoming increasingly common in data mining, and consequently,
tensor factorizations are becoming more and more important tools for data
miners. When the data is binary, it is natural to ask if we can factorize it
into binary factors while simultaneously making sure that the reconstructed
tensor is still binary. Such factorizations, called Boolean tensor
factorizations, can provide improved interpretability and find Boolean
structure that is hard to express using normal factorizations. Unfortunately
the algorithms for computing Boolean tensor factorizations do not usually scale
well. In this paper we present a novel algorithm for finding Boolean CP and
Tucker decompositions of large and sparse binary tensors. In our experimental
evaluation we show that our algorithm can handle large tensors and accurately
reconstructs the latent Boolean structure.


title: Electrically driven spin resonance in silicon carbide color centers

abstract:
  We demonstrate that the spin of optically addressable point defects can be
coherently driven with AC electric fields. Based on magnetic-dipole forbidden
spin transitions, this scheme enables spatially confined spin control, the
imaging of high-frequency electric fields, and the characterization of defect
spin multiplicity. While we control defects in SiC, these methods apply to spin
systems in many semiconductors, including the nitrogen-vacancy center in
diamond. Electrically driven spin resonance offers a viable route towards
scalable quantum control of electron spins in a dense array.


title: Homological differential calculus

abstract:
  This article provides a definition of a subdifferential for continuous
functions based on homological considerations. We show that it satisfies all
the requirement for a good notion of subdifferential. Moreover, we prove
sublinearity, a Leibniz formula and an approximation result. This work fits in
the framework of microlocal analysis of sheaves for C^0 symplectic problems and
application to Aubry-Mather theory.


title: On the transversality conditions and their genericity

abstract:
  In this note we review some results on the transversality conditions for a
smooth Fredholm map $f: X \times (0,T) \to Y$ between two Banach spaces $X,Y$.
These conditions are well-known in the realm of bifurcation theory and commonly
accepted as "generic". Here we show that under the transversality assumptions
the sections $C(t)=\{x:f(x,t)=0\}$ of the zero set of $f$ are discrete for
every $t\in (0,T)$ and we discuss a somehow explicit family of perturbations of
$f$ along which transversality holds up to a residual set.
  The application of these results to the case when $f$ is the $X$-differential
of a time-dependent energy functional $E:X\times (0,T)\to R$ and $C(t)$ is the
set of the critical points of $E$ provides the motivation and the main example
of this paper.


title: Customizing mesoscale self-assembly with 3D printing

abstract:
  Self-assembly due to capillary forces is a common method for generating 2D
mesoscale structures from identical floating particles at the liquid-air
interface. Designing building blocks to obtain a desired mesoscopic structure
is a scientific challenge. We show herein that it is possible to shape the
particles with a low cost 3D printer, for composing specific mesoscopic
structures. Our method is based on the creation of capillary multipoles
inducing either attractive or repulsive forces. Since capillary interactions
can be downscaled, our method opens new ways to low cost microfabrication.


title: ROAn, a ROOT based Analysis Framework

abstract:
  The ROOT based Offline and Online Analysis (ROAn) framework was developed to
perform data analysis on data from Depleted P-channel Field Effect Transistor
(DePFET) detectors, a type of active pixel sensors developed at the MPI
Halbleiterlabor (HLL). ROAn is highly flexible and extensible, thanks to ROOT's
features like run-time type information and reflection. ROAn provides an
analysis program which allows to perform configurable step-by-step analysis on
arbitrary data, an associated suite of algorithms focused on DePFET data
analysis, and a viewer program for displaying and processing online or offline
detector data streams. The analysis program encapsulates the applied algorithms
in objects called steps which produce analysis results. The dependency between
results and thus the order of calculation is resolved automatically by the
program. To optimize algorithms for studying detector effects, analysis
parameters are often changed. Such changes of input parameters are detected in
subsequent analysis runs and only the necessary recalculations are triggered.
This saves time and simultaneously keeps the results consistent. The viewer
program offers a configurable Graphical User Interface (GUI) and process chain,
which allows the user to adapt the program to different tasks such as offline
viewing of file data, online monitoring of running detector systems, or
performing online data analysis (histogramming, calibration, etc.). Because of
its modular design, ROAn can be extended easily, e.g. be adapted to new
detector types and analysis processes.


title: On the Bayes-optimality of F-measure maximizers

abstract:
  The F-measure, which has originally been introduced in information retrieval,
is nowadays routinely used as a performance metric for problems such as binary
classification, multi-label classification, and structured output prediction.
Optimizing this measure is a statistically and computationally challenging
problem, since no closed-form solution exists. Adopting a decision-theoretic
perspective, this article provides a formal and experimental analysis of
different approaches for maximizing the F-measure. We start with a Bayes-risk
analysis of related loss functions, such as Hamming loss and subset zero-one
loss, showing that optimizing such losses as a surrogate of the F-measure leads
to a high worst-case regret. Subsequently, we perform a similar type of
analysis for F-measure maximizing algorithms, showing that such algorithms are
approximate, while relying on additional assumptions regarding the statistical
distribution of the binary response variables. Furthermore, we present a new
algorithm which is not only computationally efficient but also Bayes-optimal,
regardless of the underlying distribution. To this end, the algorithm requires
only a quadratic (with respect to the number of binary responses) number of
parameters of the joint distribution. We illustrate the practical performance
of all analyzed methods by means of experiments with multi-label classification
problems.


title: Right-angled Artin groups and finite subgraphs of curve graphs

abstract:
  We show that for a sufficiently simple surface $S$, a right-angled Artin
group $A(\Gamma)$ embeds into $\Mod(S)$ if and only if $\Gamma$ embeds into the
curve graph $\mC(S)$ as an induced subgraph. When $S$ is sufficiently
complicated, there exists an embedding $A(\Gamma)\to\Mod(S)$ for some $\Gamma$
not contained in $\mC(S)$.


title:
Hermite-Hadamard and Simpson-like type inequalities for differentiable
  harmonically convex functions

abstract:
  In this paper, a new identity for differentiable functions is derived. A
consequence of the identity is that the author establishes some new general
inequalities containing all of the Hermite-Hadamard and Simpson-like type for
functions whose derivatives in absolute value at certain power are harmonically
convex. Some applications to special means of real numbers are also given.


title: Automaton semigroup constructions

abstract:
  The aim of this paper is to investigate whether the class of automaton
semigroups is closed under certain semigroup constructions. We prove that the
free product of two automaton semigroups that contain left identities is again
an automaton semigroup. We also show that the class of automaton semigroups is
closed under the combined operation of 'free product followed by adjoining an
identity'. We present an example of a free product of finite semigroups that we
conjecture is not an automaton semigroup. Turning to wreath products, we
consider two slight generalizations of the concept of an automaton semigroup,
and show that a wreath product of an automaton monoid and a finite monoid
arises as a generalized automaton semigroup in both senses. We also suggest a
potential counterexample that would show that a wreath product of an automaton
monoid and a finite monoid is not a necessarily an automaton monoid in the
usual sense.


title:
Effects of octahedral tilting on the electronic structure and optical
  properties of $d^0$ double perovskites $\mathbf{\rm A_2ScSbO_6}$
  ($\mathbf{\rm A=Sr, Ca}$)

abstract:
  With increasing temperature, ${\rm Sr}_2{\rm ScSbO}_6$ undergoes three
structural phase transitions at approximately ${\rm 400K}$, ${\rm 560K}$ and
${\rm 650K}$, leading to the following sequence of phases: $P2_1/n \rightarrow
I2/m \rightarrow I4/m \rightarrow Fm\bar{3}m$, making it an ideal candidate to
study the effects of octahedral tilting keeping other parameters fixed. To
ascertain the isolated effects of octahedral distortions, the electronic and
optical properties of the monoclinic $P2_1/n$ (at room temperature), monoclinic
$I2/m$ (at ${\rm 430K}$), tetragonal $I4/m$ (at ${\rm 613K}$) and the cubic
$Fm\bar{3}m$ (at ${\rm 660K}$) phases have been studied in terms of the
electronic structure, dielectric constant, optical conductivity and electron
energy loss spectroscopy using density functional theory. ${\rm Ca}_2{\rm
ScSbO}_6$, on the other hand, shows only a $P2_1/n$ phase at room temperature
and its properties have been been compared with the corresponding ${\rm Sr}$
compound. UV-Vis spectroscopic studies of the optical properties of the
room-temperature phase of these $d^0$ double perovskite have been performed and
presence of large direct bandgap for both the compounds have been reported. The
electronic bandgaps for the room temperature phases is found to be in good
agreement with the corresponding experimental values obtained using the
Kubelka-Munk function. Interestingly, in contrast to other Sc-based $d^0$
double perovskites, with increasing octahedral distortions, the effective
$t_{\rm 2g}$ bandwidth remains unaffected while the states forming the band
change due to changes in unit cell orientation, leading to small effects on the
electronic and optical properties.


title: Integrability of the AdS_5 x S^5 superstring and its deformations

abstract:
  This article reviews the application of integrability to the spectral problem
of strings on AdS_5 x S^5 and its deformations. We begin with a pedagogical
introduction to integrable field theories culminating in the description of
their finite-volume spectra through the thermodynamic Bethe ansatz. Next, we
apply these ideas to the AdS_5 x S^5 string and in later chapters discuss how
to account for particular integrable deformations. Through the AdS/CFT
correspondence this gives an exact description of anomalous scaling dimensions
of single trace operators in planar N=4 supersymmetry Yang-Mills theory, its
`orbifolds', and beta and gamma-deformed supersymmetric Yang-Mills theory. We
also touch upon some subtleties arising in these deformed theories.
Furthermore, we consider complex excited states (bound states) in the su(2)
sector and give their thermodynamic Bethe ansatz description. Finally we
discuss the thermodynamic Bethe ansatz for a quantum deformation of the AdS_5 x
S^5 superstring S-matrix, with close relations to among others Pohlmeyer
reduced string theory, and briefly indicate more recent developments in this
area.


title:
VLS-HVPE growth of ultra-long and defect-free GaAs nanowires
  investigated by ab initio simulation coupled to near-field microscopy

abstract:
  High aspect ratio, rod-like and single crystal phase GaAs nanowires (NWs)
were grown by gold catalyst-assisted hydride vapor phase epitaxy (HVPE). High
resolution transmission electron microscopy (HRTEM) and micro-Raman
spectroscopy revealed polytypism-free zinc blende NWs over lengths of several
tens of micrometers for diameters ranging between 50 and 150 nm.
Micro-photoluminescence studies of individual NWs showed linewidths smaller
than those reported elsewhere which is consistent with the crystalline quality
of the NWs. HVPE makes use of chloride growth precursors of which high
decomposition frequency, after adsorption onto the catalyst particle, favors a
direct and rapid introduction of the Ga atoms from the vapor phase into the
catalyst liquid droplet. This yields high axial growth rate (more than 100
micron/h) of NWs. The fast diffusion of the Ga atoms in the droplet towards the
interface between the liquid and the solid nanowire was investigated by using
density functional theory calculations. The diffusion coefficient of Ga atoms
was estimated to be 3x10-9 m2/s, which matches the experimental observations.


title: Implementing Computations in Automaton (Semi)groups

abstract:
  We consider the growth, order, and finiteness problems for automaton
(semi)groups. We propose new implementations and compare them with the existing
ones. As a result of extensive experimentations, we propose some conjectures on
the order of finite automaton (semi)groups.


title: Factoring Formal Maps into Reversible or Involutive Factors

abstract:
  An element $g$ of a group is called reversible if it is conjugate in the
group to its inverse. An element is an involution if it is equal to its
inverse. This paper is about factoring elements as products of reversibles in
the group $\mathfrak{G}_n$ of formal maps of $(\mathbb{C}^n,0)$, i.e.
formally-invertible $n$-tuples of formal power series in $n$ variables, with
complex coefficients. The case $n=1$ was already understood.
  Each product $F$ of reversibles has linear part $L(F)$ of determinant $\pm1$.
The main results are that for $n\ge2$ each map $F$ with det$(L(F))=\pm1$ is the
product of $2+3c$ reversibles, and may also be factored as the product of
$9+6c$ involutions, where $c$ is the smallest integer $\ge \log_2n$.


title: Radiatively-driven natural supersymmetry at the LHC

abstract:
  Radiatively-driven natural supersymmetry (RNS) potentially reconciles the Z
and Higgs boson masses close to 100 GeV with gluinos and squarks lying beyond
the TeV scale. Requiring no large cancellations at the electroweak scale in
constructing M_Z=91.2 GeV while maintaining a light Higgs scalar with m_h 125
GeV implies a sparticle mass spectrum including light higgsinos with mass
100-300 GeV, electroweak gauginos in the 300-1200 GeV range, gluinos at 1-4 TeV
and top/bottom squarks in the 1-4 TeV range (probably beyond LHC reach), while
first/second generation matter scalars can exist in the 5-30 TeV range (far
beyond LHC reach). We investigate several characteristic signals for RNS at
LHC14. Gluino pair production yields a reach up to m_{\tg} 1.7 TeV for 300
fb^{-1}. Wino pair production -- pp\to\tw_2\tz_4 and \tw_2\tw_2 -- leads to a
unique same-sign diboson (SSdB) signature accompanied by modest jet activity
from daughter higgsino decays; this signature provides the best reach up to
m_{\tg} 2.1 TeV within this framework. Wino pair production also leads to final
states with (WZ\to 3\ell)+\eslt as well as 4\ell+\eslt which give confirmatory
signals up to m_{\tg} 1.4 TeV. Directly produced light higgsinos yield a clean,
soft trilepton signature (due to very low visible energy release) which can be
visible, but only for a not-too-small a \tz_2-\tz_1 mass gap. The clean SSdB
signal -- as well as the distinctive mass shape of the dilepton mass
distribution from \tz_{2,3}\to\tz_1\ell\ell decays if this is accessible --
will mark the presence of light higgsinos which are necessary for natural SUSY.
While an e^+e^- collider operating with \sqrt{s} 600 GeV should unequivocally
reveal the predicted light higgsinos, the RNS model with m_{1/2}> 1 TeV may
elude all LHC14 search strategies even while maintaining a high degree of
electroweak naturalness.


title: Practical Provably Secure Multi-node Communication

abstract:
  We present a practical and provably-secure multimode communication scheme in
the presence of a passive eavesdropper. The scheme is based on a random
scheduling approach that hides the identity of the transmitter from the
eavesdropper. This random scheduling leads to ambiguity at the eavesdropper
with regard to the origin of the transmitted frame. We present the details of
the technique and analyze it to quantify the secrecy-fairness-overhead
trade-off. Implementation of the scheme over Crossbow Telosb motes, equipped
with CC2420 radio chips, shows that the scheme can achieve significant secrecy
gain with vanishing outage probability. In addition, it has significant
overhead advantage over direct extensions to two-nodes schemes. The technique
also has the advantage of allowing inactive nodes to leverage sleep mode to
further save energy.


title: Scalable Implementation of Boson Sampling with Trapped Ions

abstract:
  Boson sampling solves a classically intractable problem by sampling from a
probability distribution given by matrix permanents. We propose a scalable
implementation of Boson sampling using local transverse phonon modes of trapped
ions to encode the Bosons. The proposed scheme allows deterministic preparation
and high-efficiency readout of the Bosons in the Fock states and universal mode
mixing. With the state-of-the-art trapped ion technology, it is feasible to
realize Boson sampling with tens of Bosons by this scheme, which would
outperform the most powerful classical computers and constitute an effective
disproof of the famous extended Church-Turing thesis.


title: Multiple steadily translating bubbles in a Hele-Shaw channel

abstract:
  Analytical solutions are constructed for an assembly of any finite number of
bubbles in steady motion in a Hele-Shaw channel. The solutions are given in the
form of a conformal mapping from a bounded multiply connected circular domain
to the flow region exterior to the bubbles. The mapping is written as the sum
of two analytic functions---corresponding to the complex potentials in the
laboratory and co-moving frames---that map the circular domain onto respective
degenerate polygonal domains. These functions are obtained using the
generalised Schwarz-Christoffel formula for multiply connected domains in terms
of the Schottky-Klein prime function. Our solutions are very general in that no
symmetry assumption concerning the geometrical disposition of the bubbles is
made. Several examples for various bubble configurations are discussed.


title:
Countable Degree-1 Saturation of Certain C*-Algebras Which Are Coronas
  of Banach Algebras

abstract:
  We study commutants modulo some normed ideal of n-tuples of operators which
satisfy a certain approximate unit condition relative to the ideal. We obtain
results about the quotient of these Banach algebras by their ideal of compact
operators being C*-algebras which have the countable degree-1 saturation
property in the model-theory sense of I. Farah and B. Hart. We also obtain
results about quasicentral approximate units, multipliers and duality.


title:
EL CVn-type binaries - Discovery of 17 helium white dwarf precursors in
  bright eclipsing binary star systems

abstract:
  The star 1SWASP J024743.37-251549.2 was recently discovered to be a binary
star in which an A-type dwarf star eclipses the remnant of a disrupted red
giant star (WASP0247-25B). The remnant is in a rarely-observed state evolving
to higher effective temperatures at nearly constant luminosity prior to
becoming a very low-mass white dwarf composed almost entirely of helium, i.e.,
it is a pre-He-WD. We have used the WASP photometric database to find 17
eclipsing binary stars with orbital periods P=0.7 to 2.2 days with similar
lightcurves to 1SWASP J024743.37-251549.2. The only star in this group
previously identified as a variable star is the brightest one, EL CVn, which we
adopt as the prototype for this class of eclipsing binary star. The
characteristic lightcurves of EL CVn-type stars show a total eclipse by an
A-type dwarf star of a smaller, hotter star and a secondary eclipse of
comparable depth to the primary eclipse. We have used new spectroscopic
observations for 6 of these systems to confirm that the companions to the
A-type stars in these binaries have very low masses (approximately 0.2 solar
masses). This includes the companion to EL CVn which was not previously known
to be a pre-He-WD. EL CVn-type binary star systems will enable us to study the
formation of very low-mass white dwarfs in great detail, particularly in those
cases where the pre-He-WD star shows non-radial pulsations similar to those
recently discovered in WASP0247-25B.


title: Strong-randomness infinite-coupling phase in a random quantum spin chain

abstract:
  We study the ground-state phase diagram of the Ashkin-Teller random quantum
spin chain by means of a generalization of the strong-disorder renormalization
group. In addition to the conventional paramagnetic and ferromagnetic (Baxter)
phases, we find a partially ordered phase characterized by strong randomness
and infinite coupling between the colors. This unusual phase acts, at the same
time, as a Griffiths phase for two distinct quantum phase transitions both of
which are of infinite-randomness type. We also investigate the quantum
multi-critical point that separates the two-phase and three-phase regions; and
we discuss generalizations of our results to higher dimensions and other
systems.


title: A functional equation and degenerate principal series

abstract:
  A functional equation between the zeta distributions can be obtained from the
theory of prehomogeneous vector spaces. We show that the functional equation
can be extended from the Schwartz space to certain degenerate principal series.


title: Cohomology of abelian arrangements

abstract:
  An abelian arrangement is a finite set of codimension one abelian
subvarieties (possibly translated) in a complex abelian variety. In this paper,
we study the cohomology of the complement of an abelian arrangement. For
unimodular abelian arrangements, we provide a combinatorial presentation for a
differential graded algebra whose cohomology is isomorphic to the rational
cohomology of the complement. Moreover, this DGA has a bi-grading that allows
us to compute the mixed Hodge numbers.


title:
On functors between module categories for associative algebras and for
  $\mathbb{N}$-graded vertex algebras

abstract:
  We prove that the weak associativity for modules for vertex algebras are
equivalent to a residue formula for iterates of vertex operators, obtained
using the weak associativity and the lower truncation property of vertex
operators, together with a known formula expressing products of components of
vertex operators as linear combinations of iterates of components of vertex
operators. By requiring that these two formulas instead of the commutator
formula hold, we construct a functor $S$ from the category of modules for Zhu's
algebra of a vertex operator algebra $V$ to the category of
$\mathbb{N}$-gradable weak $V$-modules. We prove that $S$ has a universal
property and the functor $T$ of taking top levels of $\mathbb{N}$-gradable weak
$V$-modules is a left inverse of $S$. In particular, $S$ is equal to a functor
implicitly given by Zhu and explicitly constructed by Dong, Li and Mason and we
obtain a new construction without using relations corresponding to the
commutator formula. The hard part of this new construction is a technical
theorem stating roughly that in a module for Zhu's algebra, the relation
corresponding to the residue formula mentioned above can in fact be obtained
from the relations corresponding to the action of Zhu's algebra.


title: A pilot experience in physics laboratory for a professional school

abstract:
  The reform of the upper secondary school in Italy has recently introduced
physics in the curricula of professional schools, in realities where it was
previously absent. Many teachers, often with a temporary position, are obliged
to teaching physics in schools where the absence of the laboratory is added to
the lack of interest of students who feel this matter as very far from their
personal interests and from the preparation for the work which could expect
from a professional school. We report a leaning path for introducing students
to the measurement of simple physical quantities, which continued with the
study of some properties of matter (volume, mass, density) and ending with some
elements of thermodynamics. Educational materials designed in order to involve
students in an active learning, actions performed for improving the quality of
laboratory experience and difficulties encountered are presented. Finally, we
compare the active engagement of these students with a similar experience
performed in a very different vocational school.


title: Long Gamma Ray Bursts from binary black holes

abstract:
  We consider a scenario for the longest duration gamma ray bursts, resulting
from the collapse of a massive rotating star in a close binary system with a
companion black hole. The primary black hole born during the core collapse is
first being spun up and increases its mass during the fallback of the stellar
envelope just after its birth. As the companion black hole enters the outer
envelope, it provides an additional angular momentum to the gas. After the
infall and spiral-in towards the primary, the two black holes merge inside the
circumbinary disk. The second episode of mass accretion and high final spin of
the post-merger black hole prolongs the gamma ray burst central engine
activity. The observed events should have two distinct peaks in the
electromagnetic signal, separated by the gravitational wave emission. The
gravitational recoil of the burst engine is also possible.


title:
A remark on the number of components of the space of generalized complex
  structures

abstract:
  We give examples of generalized complex four-manifolds whose moduli space has
infinitely many components.


title:
The tension equation with holomorphic coefficients, harmonic mappings
  and rigidity

abstract:
  The tension equation for a mapping $f:{\mathbb C}\to {\mathbb C}$ is the
nonlinear second order equation \[ \Delta f +\varphi(f) f_z f_{\bar z} = 0\]
Solutions are "harmonic" mappings. Here we give a complete description of the
solution space of mappings of degree 1 to this equation when $\varphi$ is
entire. Each solution is a quasiconformal surjection and when the set of
normalised solutions is endowed with the Teichm\"uller metric, the solution
space is isometric to the hyperbolic plane. More generally, for harmonic
mappings $f:\Omega \to (\tilde{\Omega},\rho)$ between domains in ${\mathbb C}$,
with $\rho(w)|dw|$ defining a flat metric we stablish a very strong maximum
principle for the distortion - up to multiplicative factor $e^{iv}$, $v$ real
and harmonic, the Beltrami coefficient of $f^{-1}$ is quasiregular - and thus
open and discrete when nonconstant. This follows from the remarkable fact that
the Beltrami coefficient of the inverse of a harmonic mapping itself satisfies
a nonlinear homogeneous Beltrami equation.


title:
Harmonic degree 1 maps are diffeomorphisms: Lewy's theorem for curved
  metrics

abstract:
  In 1936 H. Lewy showed that the Jacobian determinant of a harmonic
homeomorphism between planar domains does not vanish and thus the map is a
diffeomorphism. This built on the earlier existence results of Rad\'o and
Kneser. R. Shoen and S.T. Yau generalised this result to degree 1 harmonic
mappings between closed Riemann surfaces. Here we give a new approach that
establishes all these results in complete generality.


title:
Single-Shot Quantum Non-Demolition Measurement of a Quantum Dot Electron
  Spin, using Cavity Exciton-Polaritons

abstract:
  We propose a scheme to perform single-shot quantum non-demolition (QND)
readout of the spin of an electron trapped in a semiconductor quantum dot (QD).
Our proposal relies on the interaction of the QD electron spin with optically
excited, quantum well (QW) microcavity exciton-polaritons. The spin-dependent
Coulomb exchange interaction between the QD electron and cavity polaritons
causes the phase and intensity response of left circularly polarized light to
be different to that of the right circularly polarized light, in such a way
that the QD electron's spin can be inferred from the response to a linearly
polarized probe. We show that, by careful design of a sample with coupled QD
and QW, it is possible to eliminate spin-flip Raman transitions. Thus, a QND
measurement of the QD electron spin can be performed within a few 10's of
nanoseconds with fidelity $\sim 99.9$%. This improves upon current optical QD
spin readout techniques across multiple metrics, including speed and
scalability.


title: Price of Anarchy for Non-atomic Congestion Games with Stochastic Demands

abstract:
  We generalize the notions of user equilibrium and system optimum to
non-atomic congestion games with stochastic demands. We establish upper bounds
on the price of anarchy for three different settings of link cost functions and
demand distributions, namely, (a) affine cost functions and general
distributions, (b) polynomial cost functions and general positive-valued
distributions, and (c) polynomial cost functions and the normal distributions.
All the upper bounds are tight in some special cases, including the case of
deterministic demands.


title: The Motion of a Pair of Charged Particles

abstract:
  We re-visit the problem of two (oppositely) charged particles interacting
electromagnetically in one dimension with retarded potentials and no radiation
reaction. The specific quantitative result of interest is the time it takes for
the particles to fall in towards one another. Starting with the
non-relativistic form, we answer this question while adding layers of
complexity until we arrive at the full relativistic delay differential equation
that governs this problem. That case can be solved using the Synge method,
which we describe and discuss.


title: On polydispersity and the hard-sphere glass transition

abstract:
  We simulate the dynamics of polydisperse hard spheres at high packing
fractions, $\phi$, with an experimentally-realistic particle size distribution
(PSD) and other commonly-used PSDs such as gaussian or top hat. We find that
the mode of kinetic arrest depends on the PSD's shape and not only on its
variance. For the experimentally-realistic PSD, the largest particles undergo
an ideal glass transition at $\phi\sim 0.588$ while the smallest particles
remain mobile. Such species-specific localisation was previously observed only
in asymmetric binary mixtures. Our findings suggest that the recent observation
of ergodic behavior up to $\phi \sim 0.6$ in a hard-sphere system is not
evidence for activated dynamics, but an effect of polydispersity.


title:
Gribov-Zwanziger action in SU(2) Maximally Abelian Gauge with U(1)$_3$
  Landau Gauge

abstract:
  We construct the local Gribov-Zwanziger action for SU(2) Euclidean Yang-Mills
theories in the maximally Abelian (MA) gauge with U(1)$_3$ Landau gauge fixing
based on the Zwanziger's work in the Landau gauge. By the restriction of the
functional integral region to the Gribov region in the MA gauge, we give the
nonlocal action. We localize the action with new fields and obtain the action
with the shift of the new scalar fields, which has the terms, corresponding to
the localized action of the horizon function in the MA gauge. The diagonal
gluon propagator in the MA gauge at tree level behaves like the propagator from
Gribov-Zwanziger action in the Landau gauge and shows the violation of
Kallen-Lehmann representation.


title: Euclidean Embeddings and Riemannian Bergman Metrics

abstract:
  Consider the sum of the first $N$ eigenspaces for the Laplacian on a
Riemannian manifold. A basis for this space determines a map to Euclidean space
and for $N$ sufficiently large the map is an embedding. In analogy with a
fruitful idea of K\"ahler geometry, we define (Riemannian) Bergman metrics of
degree $N$ to be those metrics induced by such embeddings. Our main result is
to identify a natural sequence of Bergman metrics approximating any given
Riemannian metric. In particular we have constructed finite dimensional
symmetric space approximations to the space of all Riemannian metrics. Moreover
the construction induces a Riemannian metric on that infinite dimensional
manifold which we compute explicitly.


title:
Quantitative characterization of the spin orbit torque using harmonic
  Hall voltage measurements

abstract:
  Solid understanding of current induced torques is key to the development of
current and voltage controlled magnetization dynamics in ultrathin magnetic
heterostructures. To evaluate the size and direction of such torques, or
effective fields, a number of methods have been employed. Here we examine the
adiabatic (low frequency) harmonic Hall voltage measurement that has been used
to study the effective field. We derive an analytical formula for the harmonic
Hall voltages to evaluate the effective field for both out of plane and
in-plane magnetized systems. The formula agrees with numerical calculations
based on a macrospin model. Two different in-plane magnetized films,
Pt|CoFeB|MgO and CuIr|CoFeB|MgO are studied using the formula developed. The
effective field obtained for the latter system shows relatively good agreement
with that estimated using a spin torque switching phase diagram measurements
reported previously. Our results illustrate the versatile applicability of
harmonic Hall voltage measurement for studying current induced torques in
magnetic heterostructures.


title:
Gait Velocity Estimation using time interleaved between Consecutive
  Passive IR Sensor Activations

abstract:
  Gait velocity has been consistently shown to be an important indicator and
predictor of health status, especially in older adults. It is often assessed
clinically, but the assessments occur infrequently and do not allow optimal
detection of key health changes when they occur. In this paper, we show that
the time gap between activations of a pair of Passive Infrared (PIR) motion
sensors installed in the consecutively visited room pair carry rich latent
information about a person's gait velocity. We name this time gap transition
time and show that despite a six second refractory period of the PIR sensors,
transition time can be used to obtain an accurate representation of gait
velocity.
  Using a Support Vector Regression (SVR) approach to model the relationship
between transition time and gait velocity, we show that gait velocity can be
estimated with an average error less than 2.5 cm/sec. This is demonstrated with
data collected over a 5 year period from 74 older adults monitored in their own
homes.
  This method is simple and cost effective and has advantages over competing
approaches such as: obtaining 20 to 100x more gait velocity measurements per
day and offering the fusion of location-specific information with time stamped
gait estimates. These advantages allow stable estimates of gait parameters
(maximum or average speed, variability) at shorter time scales than current
approaches. This also provides a pervasive in-home method for context-aware
gait velocity sensing that allows for monitoring of gait trajectories in space
and time.


title:
Potential fluctuations in graphene due to correlated charged impurities
  in substrate

abstract:
  We evaluate the autocorrelation function of the electrostatic potential in
doped graphene due to nearby charged impurities. The screening of those
impurities is described by a combination of the polarization function for
graphene in random phase approximation with the electrostatic Green's function
of the surrounding dielectrics. Using the hard-disk model for a two-dimensional
distribution of impurities, we show that large correlation lengths between
impurities can give rise to anti-correlation in the electrostatic potential, in
agreement with recent experiments.


title: Groups acting on hyperbolic $\Lambda$-metric spaces

abstract:
  In this paper we study group actions on hyperbolic $\Lambda$-metric spaces,
where $\Lambda$ is an ordered abelian group. $\Lambda$-metric spaces were first
introduced by Morgan and Shalen in their study of hyperbolic structures and
then Chiswell, following Gromov's ideas, introduced the notion of hyperbolicty
for such spaces. Only the case of 0-hyperbolic $\Lambda$-metric spaces (that
is, $\Lambda$-trees) was systematically studied, while the theory of general
hyperbolic $\Lambda$-metric spaces was not developed at all. Hence, one of the
goals of the present paper was to fill this gap and translate basic notions and
results from the theory of group actions on hyperbolic (in the usual sense)
spaces to the case of $\Lambda$-metric spaces for an arbitrary $\Lambda$. The
other goal was to show some principal difficulties which arise in this
generalization and the ways to deal with them.


title:
Proposed Method for Distinguishing Majorana Peak from Other Peaks:
  Tunneling Spectroscopy with Ohmic Dissipation using Resistive Electrodes

abstract:
  We propose a scheme to distinguish zero-energy peaks due to Majorana from
those due to other effects at finite temperature by simply replacing the normal
metallic lead with a resistive lead (large R k\Omega) in the tunneling
spectroscopy. The dissipation effects due to the large resistance change the
tunneling conductance significantly in different ways. The Majorana peak
remains increase as temperature decreases G T^(2r-1) for r=e^2 R/h<1/2. The
zero-energy peak due to other effects splits into two peaks at finite
temperature and the conductance at zero voltage bias varies with temperature by
a power law. The dissipative tunneling with a Majorana mode belongs to a same
universal class as the unstable critical point of the case with a non-Majorana
mode.


title:
Reaction-Diffusion Theory in the Presence of an Attractive Harmonic
  Potential

abstract:
  Problems involving the capture of a moving entity by a trap occur in a
variety of physical situations, the moving entity being an electron, an
excitation, an atom, a molecule, a biological object such as a receptor
cluster, a cell, or even an animal such as a mouse carrying an epidemic.
Theoretical considerations have almost always assumed that the particle motion
is translationally invariant. We study here the case when that assumption is
relaxed, in that the particle is additionally subjected to a harmonic
potential. This tethering to a center modifies the reaction-diffusion
phenomenon. Using a Smoluchowski equation to describe the system, we carry out
a study which is explicit in 1 dimension but can be easily extended for
arbitrary dimensions. Interesting features emerge depending on the relative
location of the trap, the attractive center and the initial placement of the
diffusing particle.