title:
Large, high quality single-crystals of the new Topological Kondo
  Insulator, SmB6

abstract:
  SmB6 has recently been predicted to be a Topological Kondo Insulator, the
first strongly correlated heavy fermion material to exhibit topological surface
states. High quality crystals are necessary to investigate the topological
properties of this material. Single crystal growth of the rare earth
hexaboride, SmB6, has been carried out by the floating zone technique using a
high power xenon arc lamp image furnace. Large, high quality single-crystals
are obtained by this technique. The crystals produced by the floating zone
technique are free of contamination from flux materials and have been
characterised by resistivity and magnetisation measurements. These crystals are
ideally suited for the investigation of both the surface and bulk properties of
SmB6.


title:
A Cs-Based Optical Frequency Measurement Using Cross-Linked Optical and
  Microwave Oscillators

abstract:
  We describe a measurement of the frequency of the 2S1/2(F = 0) - 2D3/2(F' =
2) transition of 171Yb+ at the wavelength 436 nm (frequency 688 THz), using a
single Yb+ ion confined in a Paul trap and two caesium fountains as references.
In one of the fountains, the frequency of the microwave oscillator that
interrogates the caesium atoms is stabilized by the laser that excites the Yb+
reference transition with a linewidth in the hertz range. The stability is
transferred to the microwave oscillator with the use of a fiber laser based
optical frequency comb generator that also provides the frequency conversion
for the absolute frequency measurement. The frequency comb generator is
configured as a transfer oscillator so that fluctuations of the pulse
repetition rate and of the carrier offset frequency do not degrade the
stability of the frequency conversion. The phase noise level of the generated
ultrastable microwave signal is comparable to that of a cryogenic sapphire
oscillator. For fountain operation with optical molasses loaded from a laser
cooled atomic beam source, we obtain a stability corresponding to a fractional
Allan deviation of $4.1\times 10^{-14}\ (\tau/\text{s})^{-1/2}$. With the
molasses loaded from thermal vapor and an averaging time of 65 h, we measure
the frequency of the Yb+ transition with a relative statistical uncertainty of
$2.8\times10^{-16}$ and a systematic uncertainty of $5.9\times10^{-16}$. The
frequency was also simultaneously measured with the second fountain that uses a
quartz-based interrogation oscillator. The unperturbed frequency of the Yb+
transition is realized with an uncertainty of $1.1\times10^{-16}$ that mainly
results from the uncertainty of the blackbody shift at the operating
temperature near 300 K. The transition frequency of 688 358 979 309 307.82(36)
Hz, measured with the two fountains, is in good agreement with previous
results.


title:
mJIVE-20: a survey for compact mJy radio objects with the Very Long
  Baseline Array

abstract:
  We present the description and early results of the mJy Imaging VLBA
Exploration at 20 cm (mJIVE-20). mJIVE-20 is a large project on the Very Long
Baseline Array which uses "filler" time to systematically inspect a large
sample of mJy radio sources, pre-selected from the FIRST survey made with the
Very Large Array, to identify any compact emission which may be present. The
newly available multifield capability of the VLBA makes it possible for us to
inspect of order 100 sources per hour of observing time with a 6.75 sigma
detection sensitivity of approximately 1 mJy/beam. The results of the mJIVE-20
survey are made publicly available as soon as the data are calibrated. After 18
months of observing, over 20,000 FIRST sources have been inspected, with 4,336
VLBI detections. These initial results suggest that within the range 1 - 200
mJy, fainter sources are somewhat more likely to be dominated by a very compact
component than brighter sources. Over half of all arcsecond-scale mJy radio
sources contain a compact component, although the fraction of sources which are
dominated by milliarcsecond scale structure is smaller at 30-35%, increasing
towards lower flux densities. Significant differences are seen depending on the
optical classification of the source. Radio sources with a stellar/point-like
counterpart in the Sloan Digital Sky Survey (SDSS) are more likely to be
detected overall, but this detection likelihood appears to be independent of
the arcsecond-scale radio flux density; the trend towards higher radio
compactness for fainter sources is confined to SDSS galaxies and
non-detections. These results are consistent with a unification model of AGN in
which less luminous sources have on average slower radio jets, with lower
Doppler suppression of compact core emission over a wider range of viewing
angles. (abridged)


title:
spBayes for large univariate and multivariate point-referenced
  spatio-temporal data models

abstract:
  In this paper we detail the reformulation and rewrite of core functions in
the spBayes R package. These efforts have focused on improving computational
efficiency, flexibility, and usability for point-referenced data models.
Attention is given to algorithm and computing developments that result in
improved sampler convergence rate and efficiency by reducing parameter space;
decreased sampler run-time by avoiding expensive matrix computations, and;
increased scalability to large datasets by implementing a class of predictive
process models that attempt to overcome computational hurdles by representing
spatial processes in terms of lower-dimensional realizations. Beyond these
general computational improvements for existing model functions, we detail new
functions for modeling data indexed in both space and time. These new functions
implement a class of dynamic spatio-temporal models for settings where space is
viewed as continuous and time is taken as discrete.


title: Symplectic resolutions for conical symplectic varieties

abstract:
  We introduce the notion of a conical symplectic variety, and show that any
symplectic resolution of such a variety is isomorphic to the Springer
resolution of a nilpotent orbit in a semisimple Lie algebra, composed with a
linear projection.


title:
Classical T Tauri stars: magnetic fields, coronae, and star-disc
  interactions

abstract:
  The magnetic fields of young stars set their coronal properties and control
their spin evolution via the star-disc interaction and outflows. Using 14
magnetic maps of 10 classical T Tauri stars (CTTSs) we investigate their closed
X-ray emitting coronae, their open wind-bearing magnetic fields, and the
geometry of magnetospheric accretion flows. The magnetic fields of all the
CTTSs are multipolar. Stars with simpler (more dipolar) large-scale magnetic
fields have stronger fields, are slower rotators, and have larger X-ray
emitting coronae compared to stars with more complex large-scale magnetic
fields. The field complexity controls the distribution of open and closed field
regions across the stellar surface, and strongly influences the location and
shapes of accretion hot spots. However, the higher order field components are
of secondary importance in determining the total unsigned open magnetic flux,
which depends mainly on the strength of the dipole component and the stellar
surface area. Likewise, the dipole component alone provides an adequate
approximation of the disc truncation radius. For some stars, the pressure of
the hot coronal plasma dominates the stellar magnetic pressure and forces open
the closed field inside the disc truncation radius. This is significant as
accretion models generally assume that the magnetic field has a closed geometry
out to the inner disc edge.


title:
Localized standard versus reduced formula and genus one local
  Gromov-Witten invariants

abstract:
  For local Calabi-Yau manifolds which are total spaces of vector bundle over
balloon manifolds, we propose a formal definition of reduced Genus one
Gromov-Witten invariants, by assigning contributions from the refined decorated
rooted trees. We show that this definition satisfies a localized version of the
standard versus reduced formula, whose global version in the compact cases is
due to A. Zinger. As an application we prove the conjecture in a previous
article on the genus one Gromov-Witten invariants of local Calabi-Yau manifolds
which are total spaces of concave splitting vector bundles over projective
spaces. In particular, we prove the mirror formulae for genus one Gromov-Witten
invariants of $K_{\mathbb{P}^{2}}$ and $K_{\mathbb{P}^{3}}$, conjectured by
Klemm, Zaslow and Pandharipande. In the appendix we derive the modularity of
genus one Gromov-Witten invariants for the local $\mathbb{P}^{2}$ as a
consequence of the results on Ramanujan's cubic transformation. Inspired by the
localized standard versus reduced formula, we show that the ordinary genus one
Gromov-Witten invariants of Calabi-Yau hypersurfaces in projective spaces can
be computed by virtual localization after the contribution of a genus one
vertex is replaced by a modified one.


title:
Formation and Eruption of an Active Region Sigmoid: I. Study by
  Nonlinear Force-Free Field Modeling

abstract:
  We present a magnetic analysis of the formation and eruption of an active
region (AR) sigmoid in AR 11283 from 2011 September 4 to 6. To follow the
quasi-static evolution of the coronal magnetic field, we reconstruct a time
sequence of static fields using a recently developed nonlinear force-free field
model constrained by the SDO/HMI vector magnetograms. A detailed analysis of
the fields compared with the SDO/AIA observations suggests the following
scenario for the evolution of the region. Initially, a new bipole emerges into
the negative polarity of a pre-existing bipolar AR, forming a null point
topology between the two flux systems. A weakly twisted flux rope (FR) is then
built up slowly in the embedded core region, largely through flux-cancellation
photospheric reconnections, forming a bald patch separatrix surface (BPSS)
separating the FR from its ambient field. The FR grows gradually until its axis
runs into a torus instability (TI) domain near the end of the third day, and
the BPSS also develops a fully S-shape. Unlike in the case of standard TI, the
FR does not erupt instantly since it is still attached at the photosphere along
the bald patch (BP) portion of the polarity inversion line. The combined
effects of the TI-driven expansion of the FR and the line-tying at the BP tear
the FR into two parts with the upper portion freely expelled and the lower
portion remaining behind the post-flare arcades. This process dynamically
perturbs the BPSS and results in the transient enhanced brightening of the
sigmoid. The accelerated expansion of the upper portion of the FR strongly
pushes its envelope flux near the null point and triggers breakout reconnection
at the null, as evidenced by a remarkable circular flare ribbon, which further
facilitates the eruption. We discuss the important implications of these
results for the formation and disruption of sigmoid region with FR.


title: Study of forward Z+jet production in pp collisions at $\sqrt{s} = 7$ TeV

abstract:
  A measurement of the $Z(\rightarrow\mu^+\mu^-)$+jet production cross-section
in $pp$ collisions at a centre-of-mass energy $\sqrt{s} = 7$ TeV is presented.
The analysis is based on an integrated luminosity of $1.0\,\text{fb}^{-1}$
recorded by the LHCb experiment. Results are shown with two jet transverse
momentum thresholds, 10 and 20 GeV, for both the overall cross-section within
the fiducial volume, and for six differential cross-section measurements. The
fiducial volume requires that both the jet and the muons from the Z boson decay
are produced in the forward direction ($2.0<\eta<4.5$). The results show good
agreement with theoretical predictions at the second-order expansion in the
coupling of the strong interaction.


title: Two-dimensional colloidal mixtures in magnetic and gravitational fields

abstract:
  This mini-review is concerned with two-dimensional colloidal mixtures exposed
to various kinds of external fields. By a magnetic field perpendicular to the
plane, dipole moments are induced in paramagnetic particles which give rise to
repulsive interactions leading to complex crystalline alloys in the
composition-asymmetry diagram. A quench in the magnetic field induces complex
crystal nucleation scenarios.
  If exposed to a gravitational field, these mixtures exhibit a brazil--nut
effect and show a boundary layering which is explained in terms of a depletion
bubble picture. The latter persists for time-dependent gravity ("colloidal
shaking"). Finally, we summarize crystallization effects when the second
species is frozen in a disordered matrix which provides obstacles for the
crystallizing component.


title:
Spinor derivation of quasilocal mean curvature mass in General
  Relativity

abstract:
  A spinor derivation is presented for quasilocal mean-curvature mass of
spacelike 2-surfaces in General Relativity. The derivation is based on the
Sen-Witten spinor identity and involves the introduction of novel nonlinear
boundary conditions related to the Dirac current of the spinor at the 2-surface
and the tangential flux of a boundary Dirac operator, as well the use of a spin
basis adapted to the mean curvature frame of the 2-surface normal space. This
setting may provide an alternative approach to a positivity proof for
mean-curvature mass based on showing that Witten's equation admits a spinor
solution satisfying the proposed nonlinear boundary conditions.


title: Undecidable First-Order Theories of Affine Geometries

abstract:
  Tarski initiated a logic-based approach to formal geometry that studies
first-order structures with a ternary betweenness relation \beta, and a
quaternary equidistance relation \equiv. Tarski established, inter alia, that
the first-order (FO) theory of (R^2,\beta,\equiv) is decidable. Aiello and van
Benthem (2002) conjectured that the FO-theory of expansions of (R^2,\beta) with
unary predicates is decidable. We refute this conjecture by showing that for
all n>1, the FO-theory of the class of expansions of (R^2,\beta) with just one
unary predicate is not even arithmetical. We also define a natural and
comprehensive class C of geometric structures (T,\beta), and show that for each
structure (T,\beta) in C, the FO-theory of the class of expansions of (T,\beta)
with a single unary predicate is undecidable. We then consider classes of
expansions of structures (T,\beta) with a restricted unary predicate, for
example a finite predicate, and establish a variety of related undecidability
results. In addition to decidability questions, we briefly study the
expressivities of universal MSO and weak universal MSO over expansions of
(R^n,\beta). While the logics are incomparable in general, over expansions of
(R^n,\beta), formulae of weak universal MSO translate into equivalent formulae
of universal MSO.


title: On the Solutions of infinite systems of linear equations

abstract:
  New theorems about the existence of solution for a system of infinite linear
equations with a Vandermonde type matrix of coefficients are proved. Some
examples and applications of these results are shown. In particular, a kind of
these systems is solved and applied in the field of the General Relativity
Theory of Gravitation. The solution of the system is used to construct a
relevant physical representation of certain static and axisymmetric solution of
the Einstein vacuum equations. In addition, a newtonian representation of these
relativistic solutions is recovered. It is shown as well that there exists a
relation between this application and the classical Haussdorff moment problem.


title: MCRG Flow for the nonlinear Sigma Model

abstract:
  A study of the renormalization group flow in the three-dimensional nonlinear
O(N) sigma model using Monte Carlo Renormalization Group (MCRG) techniques is
presented. To achieve this, we combine an improved blockspin transformation
with the canonical demon method to determine the flow diagram for a number of
different truncations. Systematic errors of the approach are highlighted.
Results are discussed with hindsight on the fixed point structure of the model
and the corresponding critical exponents. Special emphasis is drawn on the
existence of a nontrivial ultraviolet fixed point as required for theories
modeling the asymptotic safety scenario of quantum gravity.


title:
A U-statistic estimator for the variance of resampling-based error
  estimators

abstract:
  We revisit resampling procedures for error estimation in binary
classification in terms of U-statistics. In particular, we exploit the fact
that the error rate estimator involving all learning-testing splits is a
U-statistic. Thus, it has minimal variance among all unbiased estimators and is
asymptotically normally distributed. Moreover, there is an unbiased estimator
for this minimal variance if the total sample size is at least the double
learning set size plus two. In this case, we exhibit such an estimator which is
another U-statistic. It enjoys, again, various optimality properties and yields
an asymptotically exact hypothesis test of the equality of error rates when two
learning algorithms are compared. Our statements apply to any deterministic
learning algorithms under weak non-degeneracy assumptions.


title: Sequencing and navigation through learning content

abstract:
  The aim of this paper is to describe a basic idea to introduce formal
modeling in development and presentation of e-learning systems. By introducing
formalism, reasoning on e-learning systems and processes through them can be
more easily understood. In particular, we propose to use Harel automata
(statecharts) in modeling sequencing and navigation through learning content
and learning process.


title: Accretion in supergiant High Mass X-ray Binaries

abstract:
  Supergiant High Mass X-ray Binary systems (sgHMXBs) consist of a massive,
late type, star and a neutron star. The massive stars exhibits strong,
radiatively driven, stellar winds. Wind accretion onto compact object triggers
X-ray emission, which alters the stellar wind significantly. Hydrodynamic
simulation has been used to study the neutron star - stellar wind interaction
it two sgHMXBs: i) A heavily obscured sgHMXB (IGR J17252-3616) discovered by
INTEGRAL. To account for observable quantities (i.e., absorbing column density)
we have to assume a very slow wind terminal velocity of about 500 km/s and a
rather massive neutron star. If confirmed in other obscured systems, this could
provide a completely new stellar wind diagnostics. ii) A classical sgHMXB (Vela
X-1) has been studied in depth to understand the origin of the off-states
observed in this system. Among many models used to account for this observed
behavior (clumpy wind, gating mechanism) we propose that self-organized
criticality of the accretion stream is the likely reason for the observed
behavior. In conclusion, the neutron star, in these two examples, acts very
efficiently as a probe to study stellar winds.


title:
Deconfinement transition at weak coupling in Yang-Mills theory on a
  torus

abstract:
  We describe a weak coupling realization of the deconfinement transition in
gauge theory compactified on $R^3\times S^1$. We consider Yang-Mills theory
with a single Weyl fermion of mass $m$ in the adjoint representation of the
gauge group. The fermion is subject to periodic boundary conditions,
$\lambda(0)=\lambda(L)$, where $L$ is the size of the circle $S_1$. This theory
reduces to thermal Yang-Mills theory in the limit $m\to\infty$. In the limit
$m\to 0$ the deconfinement transition can be studied using weak coupling
methods. The analysis is based on semi-classical objects characterized by
topological and magnetic charges. At leading order the relevant configurations
are monopole-instantons and monopole-anti-monopole pairs ("bions"). We argue
that in the $m-L$ plane the weak coupling transition is continuously connected
to the deconfinement transition in pure gauge theory.


title: Oracle Inequalities for High-Dimensional Panel Data Models

abstract:
  This paper is concerned with high-dimensional panel data models where the
number of regressors can be much larger than the sample size. Under the
assumption that the true parameter vector is sparse we propose a panel-Lasso
estimator and establish finite sample upper bounds on its estimation error
under two different sets of conditions on the covariates as well as the error
terms. In particular, we allow for heteroscedastic and non-gaussian error terms
which are weakly dependent over time. Upper bounds on the estimation error of
the unobserved heterogeneity are also provided under the assumption of
sparsity. Next, we show that our upper bounds are essentially optimal in the
sense that they can only be improved by multiplicative constants. These results
are then used to show that the Lasso can be consistent in even very large
models where the number of regressors increases at an exponential rate in the
sample size. Conditions under which the Lasso does not discard any relevant
variables asymptotically are also provided.
  In the second part of the paper we give lower bounds on the probability with
which the adaptive Lasso selects the correct sparsity pattern in finite
samples. These results are then used to give conditions under which the
adaptive Lasso can detect the correct sparsity pattern asymptotically. We
illustrate our finite sample results by simulations and apply the methods to
search for covariates explaining growth in the G8 countries.


title:
Probing the effects of interaction in Anderson localization using linear
  photonic lattices

abstract:
  We show how two-dimensional waveguide arrays can be used to probe the effect
of on-site interaction on Anderson localization of two interacting bosons in
one dimension. It is shown that classical light and linear elements are
sufficient to experimentally probe the interplay between interaction and
disorder in this setting. For experimental relevance, we evaluate the
participation ratio and the intensity correlation function as measures of
localization for two types of disorder (diagonal and off-diagonal), for two
types of interaction (repulsive and attractive), and for a variety of initial
input states. Employing a commonly used set of initial states, we show that the
effect of interaction on Anderson localization is strongly dependent on the
type of disorder and initial conditions, but is independent of whether the
interaction is repulsive or attractive. We then analyze a certain type of
entangled input state where the type of interaction is relevant and discuss how
it can be naturally implemented in waveguide arrays. We conclude by laying out
the details of the two-dimensional photonic lattice implementation including
the required parameter regime.


title: Convergence in Norm of logarithmic means of Multiple Fourier series

abstract:
  The maximal Orlicz space such that the mixed logarithmic means of multiple
Fourier series for the functions from this space converge in $L_{1}$-norm is
found.


title: Phase diagram and optical conductivity of La1.8-xEu0.2SrxCuO4

abstract:
  La1.8-xEu0.2SrxCuO4 (LESCO) is the member of the 214 family which exhibits
the largest intervals among the structural, charge ordering (CO), magnetic, and
superconducting transition temperatures. By using new dc transport measurements
and data in the literature we construct the phase diagram of LESCO between x =
0.8 and 0.20. This phase diagram has been further probed in ac, by measuring
the optical conductivity {\sigma}1({\omega}) of three single crystals with x =
0.11, 0.125, and 0.16 between 10 and 300 K in order to associate the
extra-Drude peaks often observed in the 214 family with a given phase. The
far-infrared peak we detect in underdoped LESCO is the hardest among them,
survives up to room temperature and is associated with charge localization
rather than with ordering. At the CO transition for the commensurate doping x =
0.125 instead the extra-Drude peak hardens and a pseudogap opens in
{\sigma}1({\omega}), approximately as wide as the maximum superconducting gap
of LSCO.


title: (Re)partitioning for stream-enabled computation

abstract:
  Partitioning an input graph over a set of workers is a complex operation.
Objectives are twofold: split the work evenly, so that every worker gets an
equal share, and minimize edge cut to achieve a good work locality (i.e.
workers can work independently). Partitioning a graph accessible from memory is
a notorious NP-complete problem. Motivated by the regain of interest for the
stream processing paradigm (where nodes and edges arrive as a flow to the
datacenter), we propose in this paper a stream-enabled graph partitioning
system that constantly seeks an optimum between those two objectives. We first
expose the hardness of partitioning using classic and static methods; we then
exhibit the cut versus load balancing tradeoff, from an application point of
view. With this tradeoff in mind, our approach translates the online
partitioning problem into a standard optimization problem. A greedy algorithm
handles the stream of incoming graph updates while optimizations are triggered
on demand to improve upon the greedy decisions. Using simulations, we show that
this approach is very efficient, turning a basic optimization strategy such as
hill climbing into an online partitioning solution that compares favorably to
literature's recent stream partitioning solutions.


title: Almost Everywhere Strong Summability of Double Walsh-Fourier Series

abstract:
  In this paper we study the a. e. strong convergence of the quadratical
partial sums of the two-dimensional Walsh-Fourier series. Namely, we prove the
a.e. relation $(\frac{1}{n}\sum\limits_{m=0}^{n-1}\left\vert S_{mm}f - f
\right\vert^{p})^{1/p}\rightarrow 0$ for every two-dimensional functions
belonging to $L\log L$ and $0<p\le 2$. From the theorem of Getsadze \cite{Gets}
it follows that the space $L\log L$ can not be enlarged with preserving this
strong summability property.


title:
A theoretical study on the performances of thermoelectric heat engine
  and refrigerator with two-dimensional electron reservoirs

abstract:
  Theoretical thermoelectric nanophysics models of low-dimensional electronic
heat engine and refrigerator devices, comprising two-dimensional hot and cold
reservoirs and an interconnecting filtered electron transport mechanism have
been established. The models were used to numerically simulate and evaluate the
thermoelectric performance and energy conversion efficiencies of these
low-dimensional devices, based on three different types of electron transport
momentum-dependent filters, referred to herein as: kx, ky and kr filters.
Assuming the Fermi-Dirac distribution of electrons, expressions for key
thermoelectric performance parameters were derived for the resonant transport
processes, in which the transmission of electrons has been approximated as a
Lorentzian resonance function. Optimizations were carried out and the
corresponding optimized design parameters have been determined, including but
not limited to the universal theoretical upper bound of the efficiency at
maximum power for heat engines, and the maximum coefficient of performance for
refrigerators. From the results, it was determined that kr filter delivers the
best thermoelectric performance, followed by the kx filter, and then the ky
filter. For refrigerators with any one of three filters, an optimum range for
the full width at half maximum of the transport resonance was found to be <2kT .


title:
First results from the LUX dark matter experiment at the Sanford
  Underground Research Facility

abstract:
  The Large Underground Xenon (LUX) experiment, a dual-phase xenon
time-projection chamber operating at the Sanford Underground Research Facility
(Lead, South Dakota), was cooled and filled in February 2013. We report results
of the first WIMP search dataset, taken during the period April to August 2013,
presenting the analysis of 85.3 live-days of data with a fiducial volume of 118
kg. A profile-likelihood analysis technique shows our data to be consistent
with the background-only hypothesis, allowing 90% confidence limits to be set
on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit
on the cross section of $7.6 \times 10^{-46}$ cm$^{2}$ at a WIMP mass of 33
GeV/c$^2$. We find that the LUX data are in strong disagreement with low-mass
WIMP signal interpretations of the results from several recent direct detection
experiments.

categories: astro-ph.CO astro-ph.IM hep-ex physics.ins-det


title: Intersecting D6-branes on the Z_{12}-II orientifold

abstract:
  Much work has been done by a number of authors with the aim of constructing
the supersymmetric Standard Model in type IIA intersecting-brane theories
compactified on an orientifold with various Z_N or Z_M x Z_N point groups. Here
we consider the Z_{12} point group which has previously received comparatively
little attention. We consider intersecting D6-branes that wrap 3-cycles
consisting of a 2-cycle of the 4-dimensional lattice upon which the Z_{12} is
realised times a 1-cycle of the remaining 2-torus. Our discussion is restricted
to the case when these 2-cycles are "factorisable" in the sense discussed in
section 3. Although it is possible to find models with the correct
supersymmetric Standard Model quark-doublet content, we have not found it
possible to obtain the correct quark-singlet content.


title: Spectra of large diluted but bushy random graphs

abstract:
  We compute an asymptotic expansion in $1/c$ of the limit in $n$ of the
empirical spectral measure of the adjacency matrix of an Erd\H{o}s-R\'enyi
random graph with $n$ vertices and parameter $c/n$. We present two different
methods, one of which is valid for the more general setting of locally
tree-like graphs. The second order in the expansion gives some information
about the edge.


title:
Existence and stability for a non-local isoperimetric model of charged
  liquid drops

abstract:
  We consider a variational problem related to the shape of charged liquid
drops at equilibrium. We show that this problem never admits global minimizers
with respect to $L^1$ perturbations preserving the volume. This leads us to
study it in more regular classes of competitors, for which we show existence of
minimizers. We then prove that the ball is the unique solution for sufficiently
small charges.


title:
An optical spectroscopic survey of the 3CR sample of radio galaxies with
  z<0.3. V. Implications for the unified model for FRIIs

abstract:
  We explore the implications of our optical spectroscopic survey of 3CR radio
sources with z<0.3 for the unified model (UM) for radio-loud AGN, focusing on
objects with a FRII radio morphology. The sample contains 33 high ionization
galaxies (HIGs) and 18 broad line objects (BLOs). According to the UM, HIGs,
the narrow line sources, are the nuclearly obscured counterparts of BLOs. The
fraction of HIGs indicates a covering factor of the circumnuclear matter of 65%
that corresponds, adopting a torus geometry, to an opening angle of 50+/-5
degree. No dependence on redshift and luminosity on the torus opening angle
emerges. We also consider the implications for a 'clumpy' torus. The
distributions of radio luminosity of HIGs and BLOs are not statistically
distinguishable, as expected from the UM. Conversely, BLOs have a radio core
dominance, R, more than ten times larger than HIGs, as expected in case of jet
Doppler boosting. Modeling the R distributions leads to an estimate of the jet
bulk Lorentz factor of Gamma ~3-5. The test of the UM based on the radio source
size is not conclusive due to the limited number of objects. Studying the
emission line ([OIII], [OII]and [OI]) properties of HEGs and BLOs, we find
evidences of a narrow line region (NLR) density stratification and its partial
obscuration from the torus. In conclusion, the radio and NLR properties of HIGs
and BLOs are consistent with the UM predictions. We also explored the radio
properties of 21 3CR FRII low-ionization galaxies (LIGs) at z<0.3. We find that
they cannot be part of the model that unifies HIGs and BLOs, but they are
instead intrinsically different source, still reproduced by a randomly oriented
population.


title:
Comparative model accuracy of a data-fitted generalized Aw-Rascle-Zhang
  model

abstract:
  The Aw-Rascle-Zhang (ARZ) model can be interpreted as a generalization of the
Lighthill-Whitham-Richards (LWR) model, possessing a family of fundamental
diagram curves, each of which represents a class of drivers with a different
empty road velocity. A weakness of this approach is that different drivers
possess vastly different densities at which traffic flow stagnates. This
drawback can be overcome by modifying the pressure relation in the ARZ model,
leading to the generalized Aw-Rascle-Zhang (GARZ) model. We present an approach
to determine the parameter functions of the GARZ model from fundamental diagram
measurement data. The predictive accuracy of the resulting data-fitted GARZ
model is compared to other traffic models by means of a three-detector test
setup, employing two types of data: vehicle trajectory data, and sensor data.
This work also considers the extension of the ARZ and the GARZ models to models
with a relaxation term, and conducts an investigation of the optimal relaxation
time.


title: Prediction of highly cited papers

abstract:
  In an article written five years ago [arXiv:0809.0522], we described a method
for predicting which scientific papers will be highly cited in the future, even
if they are currently not highly cited. Applying the method to real citation
data we made predictions about papers we believed would end up being well
cited. Here we revisit those predictions, five years on, to see how well we
did. Among the over 2000 papers in our original data set, we examine the fifty
that, by the measures of our previous study, were predicted to do best and we
find that they have indeed received substantially more citations in the
intervening years than other papers, even after controlling for the number of
prior citations. On average these top fifty papers have received 23 times as
many citations in the last five years as the average paper in the data set as a
whole, and 15 times as many as the average paper in a randomly drawn control
group that started out with the same number of citations. Applying our
prediction technique to current data, we also make new predictions of papers
that we believe will be well cited in the next few years.


title: Quantum mechanics over sets

abstract:
  In the tradition of toy models of quantum mechanics in vector spaces over
finite fields (e.g., Schumacher and Westmoreland's "modal quantum theory"), one
finite field stands out, 2, since vectors over 2 have an interpretation as
natural mathematical objects, i.e., sets. This engages a sets-to-vector-spaces
bridge that is part of the mathematical folklore to translate both ways between
set concepts and vector space concepts. Using that bridge, the mathematical
framework of (finite-dimensional) quantum mechanics can be transported down to
sets resulting in quantum mechanics over sets or QM/sets. This approach leads
to a different treatment of Dirac's brackets than in "modal quantum theory"
(MQT), and that gives a full probability calculus (unlike MQT that only has
zero-one modalities of impossible and possible). That, in turn, leads to a
rather fulsome theory of QM over sets that includes "logical" models of the
double-slit experiment, Bell's Theorem, quantum information theory, quantum
computing, and much else. Indeed, QM/sets is proposed as the "logic" of QM in
the old-fashioned sense of "logic" as giving the simplified essentials of a
theory. QM/sets is also a key part of a broader research program to provide an
interpretation of QM based on the notion of "objective indefiniteness," a
program that grew out the recent development of the logic of partitions
mathematically dual to the usual Boolean logic of subsets.


title: Rheology of Cubic Blue Phases

abstract:
  We study the behaviour of cubic blue phases under shear flow via lattice
Boltzmann simulations. We focus on the two experimentally observed phases, Blue
Phase I (BPI) and Blue Phase II (BPII). The disclination network of Blue Phase
II continuously breaks and reforms under steady shear, leading to an
oscillatory stress response in time. For larger shear rates, the structure
breaks up into a Grandjean texture with a cholesteric helix lying along the
flow gradient direction. Blue Phase I leads to a very different response. Here,
oscillations are only possible for intermediate shear rates -- very slow flow
causes a transition of the initially ordered structure into an amorphous
network with an apparent yield stress. Larger shear rates lead to another
amorphous state with different structure of the defect network. For even larger
flow rates the same break-up into a Grandjean texture as for Blue Phase II is
observed. At the highest imposed flow rates both cubic blue phases adopt a
flow-aligned nematic state. Our results provide the first theoretical
investigation of sheared blue phases in large systems, and are relevant to
understanding the bulk rheology of these materials.


title:
Non-Ideal Magnetohydrodynamic Simulations of the Two-Stage Fragmentation
  Model for Cluster Formation

abstract:
  We model molecular cloud fragmentation with thin disk non-ideal
magnetohydrodynamic simulations that include ambipolar diffusion and partial
ionization that transitions from primarily ultraviolet dominated to cosmic ray
dominated regimes. These simulations are used to determine the conditions
required for star clusters to form through a two-stage fragmentation scenario.
Recent linear analyses have shown that the fragmentation length and time scales
can undergo a dramatic drop across the column density boundary that separates
the ultraviolet and cosmic ray dominated ionization regimes. As found in
earlier studies, the absence of an ionization drop and regular perturbations
leads to a single-stage fragmentation on parsec scales in transcritical clouds,
so that the nonlinear evolution yields the same fragment sizes as predicted by
linear theory. However, we find that a combination of initial transcritical
mass-to-flux ratio, evolution through a column density regime in which the
ionization drop takes place, and regular small perturbations to the
mass-to-flux ratio are sufficient to cause a second stage of fragmentation
during the nonlinear evolution. Cores of size ~0.1 pc are formed within an
initial fragment of ~ pc size. Regular perturbations to the mass-to-flux ratio
also accelerate the onset of runaway collapse.


title: Transitive Reduction of Citation Networks

abstract:
  In many complex networks the vertices are ordered in time, and edges
represent causal connections. We propose methods of analysing such directed
acyclic graphs taking into account the constraints of causality and
highlighting the causal structure. We illustrate our approach using citation
networks formed from academic papers, patents, and US Supreme Court verdicts.
We show how transitive reduction reveals fundamental differences in the
citation practices of different areas, how it highlights particularly
interesting work, and how it can correct for the effect that the age of a
document has on its citation count. Finally, we transitively reduce null models
of citation networks with similar degree distributions and show the difference
in degree distributions after transitive reduction to illustrate the lack of
causal structure in such models.


title: Exploring the Causal Structures of Almost Commutative Geometries

abstract:
  We investigate the causal relations in the space of states of almost
commutative Lorentzian geometries. We fully describe the causal structure of a
simple model based on the algebra $\mathcal{S}(\mathbb{R}^{1,1}) \otimes
M_2(\mathbb{C})$, which has a non-trivial space of internal degrees of freedom.
It turns out that the causality condition imposes restrictions on the motion in
the internal space. Moreover, we show that the requirement of causality favours
a unitary evolution in the internal space.


title: Bibliometric-enhanced Information Retrieval

abstract:
  Bibliometric techniques are not yet widely used to enhance retrieval
processes in digital libraries, although they offer value-added effects for
users. In this workshop we will explore how statistical modelling of
scholarship, such as Bradfordizing or network analysis of coauthorship network,
can improve retrieval services for specific communities, as well as for large,
cross-domain collections. This workshop aims to raise awareness of the missing
link between information retrieval (IR) and bibliometrics/scientometrics and to
create a common ground for the incorporation of bibliometric-enhanced services
into retrieval at the digital library interface.


title: Thermo-diffusion in inertially confined plasmas

abstract:
  In a plasma of multiple ion species, thermodynamic forces such as pressure
and temperature gradients can drive ion species separation via inter-species
diffusion. Unlike its neutral mix counterpart, plasma thermo-diffusion is found
comparable to, or even much larger than, baro-diffusion. It is shown that such
a strong effect is due to the long-range nature of the Coulomb potential, as
opposed to short-range interactions in neutral gases. A special composition of
the tritium and 3He fuel is identified to have vanishing net diffusion during
adiabatic compression, and hence provides an experimental test in which yield
degradation is minimized during ICF implosions.


title:
Search for narrow six-quark states in the reactions $\gamma d\to
  \pi\gamma nn$

abstract:
  We study the reactions $\gamma d\to\pi\gamma NN$ with the aim to search for
six-quark states, the decay of which into two nucleons is forbidden by the
Pauli exclusion principle. These states with the masses $M<2m_N+m_{\pi}$ should
mainly decay by emitting a photon. This is a new class of metastable six-quark
states with the decay widths $<< 1$keV. The recent experiment at Proton Linear
Accelerator of INR (Moscow) suggests a possibility of the existence of such
states with masses 1904, 1926, and 1942 MeV. The proposed experiment at MAMI-C
could provide an unique opportunity to observe such dibaryon states in mass
region up to 2000 MeV and determine their masses and quantum numbers.


title:
Discovery of possible molecular counterparts to the infrared Double
  Helix Nebula in the Galactic center

abstract:
  We have discovered two molecular features at radial velocities of -35 km/s
and 0 km/s toward the infrared Double Helix Nebula (DHN) in the Galactic center
with NANTEN2. The two features show good spatial correspondence with the DHN.
We have also found two elongated molecular ridges at these two velocities
distributed vertically to the Galactic plane over 0.8 degree. The two ridges
are linked by broad features in velocity and are likely connected physically
with each other. The ratio between the 12CO J=2-1 and J=1-0 transitions is 0.8
in the ridges which is larger than the average value 0.5 in the foreground gas,
suggesting the two ridges are in the Galactic center. An examination of the K
band extinction reveals a good coincidence with the CO 0 km/s ridge and is
consistent with a distance of 8 +/-2 kpc. We discuss the possibility that the
DHN was created by a magnetic phenomenon incorporating torsional Alfv\'en waves
launched from the circumnuclear disk (Morris, Uchida & Do 2006) and present a
first estimate of the mass and energy involved in the DHN.


title: Cosmic Rays from Heavy Dark Matter from the Galactic Center

abstract:
  The gamma-ray fluxes observed by the High Energy Stereoscopic System (HESS)
from the J1745-290 Galactic Center source is well fitted by the secondary
photons coming from Dark Matter (DM) annihilation in particle-antiparticle
standard model pairs over a diffuse power-law background. The spectral features
of the signal are consistent with different channels: light quarks,
electro-weak gauge bosons and top-antitop production. The amount of photons and
morphology of the signal localized within a region of few parsecs, require
compressed DM profiles as those resulting from baryonic contraction, which
offer large enhancements in the signal over DM alone simulations. The fits
return a heavy WIMP, with a mass above 10 TeV, but well below the unitarity
limit for thermal relic annihilation. The fitted background spectral index is
compatible with the Fermi-Large Area Telescope (LAT) data from the same region.
This possibility can be potentially tested with the observations of other high
energy cosmic rays.


title: Towards a density of states approach for dense matter systems

abstract:
  The density-of-states method (Phys.Rev.Lett. 109 (2012) 111601) features an
exponential error suppression and is not restricted to theories with positive
probabilistic weight. It is applied to the SU(2) gauge theory at finite
densities of heavy quarks. The key ingredient here is the Polyakov line
probability distribution, which is obtained of over 80 orders of magnitude. We
briefly address whether the exponential error suppression could be sufficient
to simulate theories with a strong sign problem.


title:
Improving Memory Hierarchy Utilisation for Stencil Computations on
  Multicore Machines

abstract:
  Although modern supercomputers are composed of multicore machines, one can
find scientists that still execute their legacy applications which were
developed to monocore cluster where memory hierarchy is dedicated to a sole
core. The main objective of this paper is to propose and evaluate an algorithm
that identify an efficient blocksize to be applied on MPI stencil computations
on multicore machines. Under the light of an extensive experimental analysis,
this work shows the benefits of identifying blocksizes that will dividing data
on the various cores and suggest a methodology that explore the memory
hierarchy available in modern machines.


title: Noise robustness in the detection of non separable random unitary maps

abstract:
  We briefly review a recently proposed method to detect properties of quantum
noise processes and quantum channels. We illustrate in detail the method for
detecting non separable random unitary channels and consider in particular the
explicit examples of the CNOT and CZ gates. We analyse their robustness in the
presence of noise for several quantum noise models.


title: Exact Solution for One Dimensional Multibarrier Tunneling

abstract:
  Quantum tunneling across multiple barriers as yet is an unsolved problem for
barrier numbers greater than five. The complexity of the mathematical analysis
even for small number of barriers pushed it into the realms of Numerical
Analysis. This work is aimed at providing a rigorously correct solution to the
general N barrier problem, where N can be any positive integer. An exact
algebraic solution has been presented, which overcomes the complexity of the
WKB integrals that are traditionally employed, and matches the earlier results
reported for small number of barriers. The solution has been explored to
considerable depth and many startling consequences have been pointed out for
500 and 1000 barriers. These are quite revealing and open up many avenues for
engineering applications and further research.


title:
Spin-orbit-torque magnetization switching of a three terminal
  perpendicular magnetic tunnel junction

abstract:
  We report on the current-induced magnetization switching of a three-terminal
perpendicular magnetic tunnel junction by spin-orbit torque and the read-out
using the tunnelling magnetoresistance (TMR) effect. The device is composed of
a perpendicular Ta/FeCoB/MgO/FeCoB stack on top of a Ta current line. The
magnetization of the bottom FeCoB layer can be switched reproducibly by the
injection of current pulses with density $5\times10^{11}$ A/m$^2$ in the Ta
layer in the presence of an in-plane bias magnetic field, leading to the
full-scale change of the TMR signal. Our work demonstrates the proof of concept
of a perpendicular spin-orbit torque magnetic memory cell.


title:
Design and analysis of experiments linking on-line drilling methods to
  improvements in knowledge

abstract:
  An on-line drilling system, the tutor-web, has been developed and used for
teaching mathematics and statistics. The system was used in a basic course in
calculus including 182 students. The students were requested to answer quiz
questions in the tutor-web and therefore monitored continuously during the
semester. Data available are grades on a status exam conducted in the beginning
of the course, a final grade and data gathered in the tutor-web system. A
classification of the students is proposed using the data gathered in the
system; a Good student should be able to solve a problem quickly and get it
right, the "diligent" hard-working Learner may take longer to get the right
answer, a guessing (Poor) student will not take long to get the wrong answer
and the remaining (Unclassified) apparent non-learning students take long to
get the wrong answer, resulting in a simple classification GLUP. The (Poor)
students were found to show the least improvement, defined as the change in
grade from the status to the final exams, while the Learners were found to
improve the most. The results are used to demonstrate how further experiments
are needed and can be designed as well as to indicate how a system needs to be
further developed to accommodate such experiments.


title: Geometry-induced superdiffusion in driven crowded systems

abstract:
  Recent Molecular Dynamics simulations of glass-forming liquids revealed
superdiffusive fluctuations associated with the position of a tracer particle
(TP) driven by an external force. Such anomalous response, whose mechanism
remains elusive, has been observed up to now only in systems close to their
glass transition, suggesting that this could be one of its hallmarks. Here, we
show that the presence of superdiffusion is in actual fact much more general,
provided that the system is crowded and geometrically confined. We present and
solve analytically a minimal model consisting of a driven TP in a dense,
crowded medium in which the motion of particles is mediated by the diffusion of
packing defects, called vacancies. For such non glass-forming systems, our
analysis predicts a long-lived superdiffusion which ultimately crosses over to
giant diffusive behavior. We find that this trait is present in confined
geometries, for example long capillaries and stripes, and emerges as a
universal response of crowded environments to an external force. These findings
are confirmed by numerical simulations of systems as varied as lattice-gases,
dense liquids and granular fluids.


title: Search for lepton-number violating B+ -> X- l+ l'+ decays

abstract:
  We report on a search for eleven lepton-number violating processes B+ -> X-
l+ l'+ with X- = K-, pi-, rho-, K*- or D- and l+/l'+ = e+ or mu+, using a
sample of 471+/-3 million BBbar events collected with the BaBar detector at the
PEP-II e+e- collider at the SLAC National Accelerator Laboratory. We find no
evidence for any of these modes and place 90% confidence level upper limits on
their branching fractions in the range $(1.5-26)\times 10^{-7}$.


title: Remarks on limit theorems for reversible Markov processes

abstract:
  We propose some backward-forward martingale decompositions for functions of
reversible Markov chains. These decompositions are used to prove the functional
CLT for reversible Markov chains with asymptotically linear variance of partial
sums. We also provide a proof of the equivalence between asymptotic linearity
of the variance and convergence of the integral of $1/(1-t)$ with respect to
the associated spectral measure $\rho$. We also study the asymptotic behavior
of linear processes having as innovations mean zero square integrable functions
of stationary reversible Markov chains. We apply this study to several cases of
reversible stationary Markov chains that arise in regression estimation.


title:
On the optimal estimation of probability measures in weak and strong
  topologies

abstract:
  Given random samples drawn i.i.d. from a probability measure $\mathbb{P}$
(defined on say, $\mathbb{R}^d$), it is well-known that the empirical estimator
is an optimal estimator of $\mathbb{P}$ in weak topology but not even a
consistent estimator of its density (if it exists) in the strong topology
(induced by the total variation distance). On the other hand, various popular
density estimators such as kernel and wavelet density estimators are optimal in
the strong topology in the sense of achieving the minimax rate over all
estimators for a Sobolev ball of densities. Recently, it has been shown in a
series of papers by Gin\'{e} and Nickl that these density estimators on
$\mathbb{R}$ that are optimal in strong topology are also optimal in
$\|\cdot\|_{\mathcal{F}}$ for certain choices of $\mathcal{F}$ such that
$\|\cdot\|_{\mathcal{F}}$ metrizes the weak topology, where
$\|\mathbb{P}\|_{\mathcal{F}}:=\sup\{\int f\,\mathrm{d}\mathbb{P}:
f\in\mathcal{F}\}$. In this paper, we investigate this problem of optimal
estimation in weak and strong topologies by choosing $\mathcal{F}$ to be a unit
ball in a reproducing kernel Hilbert space (say $\mathcal{F}_H$ defined over
$\mathbb{R}^d$), where this choice is both of theoretical and computational
interest. Under some mild conditions on the reproducing kernel, we show that
$\|\cdot\|_{\mathcal{F}_H}$ metrizes the weak topology and the kernel density
estimator (with $L^1$ optimal bandwidth) estimates $\mathbb{P}$ at dimension
independent optimal rate of $n^{-1/2}$ in $\|\cdot\|_{\mathcal{F}_H}$ along
with providing a uniform central limit theorem for the kernel density
estimator.


title: On mixtures of copulas and mixing coefficients

abstract:
  We show that if the density of the absolutely continuous part of a copula is
bounded away from zero on a set of Lebesgue measure 1, then that copula
generates \textquotedblleft lower $\psi$-mixing\textquotedblright\ stationary
Markov chains. This conclusion implies $\phi$-mixing, $\rho$-mixing,
$\beta$-mixing and \textquotedblleft interlaced $\rho$-mixing\textquotedblright
. We also provide some new results on the mixing structure of Markov chains
generated by mixtures of copulas.


title: Passive Magnetic Shielding in Gradient Fields

abstract:
  The effect of passive magnetic shielding on dc magnetic field gradients
imposed by both external and internal sources is studied. It is found that for
concentric cylindrical or spherical shells of high permeability material,
higher order multipoles in the magnetic field are shielded progressively
better, by a factor related to the order of the multipole. In regard to the
design of internal coil systems for the generation of uniform internal fields,
we show how one can take advantage of the coupling of the coils to the
innermost magnetic shield to further optimize the uniformity of the field.
These results demonstrate quantitatively a phenomenon that was previously
well-known qualitatively: that the resultant magnetic field within a passively
magnetically shielded region can be much more uniform than the applied magnetic
field itself. Furthermore we provide formulae relevant to active magnetic
compensation systems which attempt to stabilize the interior fields by sensing
and cancelling the exterior fields close to the outermost magnetic shielding
layer. Overall this work provides a comprehensive framework needed to analyze
and optimize dc magnetic shields, serving as a theoretical and conceptual
design guide as well as a starting point and benchmark for finite-element
analysis.


title: Para-active learning

abstract:
  Training examples are not all equally informative. Active learning strategies
leverage this observation in order to massively reduce the number of examples
that need to be labeled. We leverage the same observation to build a generic
strategy for parallelizing learning algorithms. This strategy is effective
because the search for informative examples is highly parallelizable and
because we show that its performance does not deteriorate when the sifting
process relies on a slightly outdated model. Parallel active learning is
particularly attractive to train nonlinear models with non-linear
representations because there are few practical parallel learning algorithms
for such models. We report preliminary experiments using both kernel SVMs and
SGD-trained neural networks.


title:
Rates of convergence in conditional covariance matrix with nonparametric
  entries estimation

abstract:
  Let $X\in \mathbb{R}^p$ and $Y\in \mathbb{R}$ be two random variables. We
estimate the conditional covariance matrix
$\mathrm{Cov}\left(\mathrm{E}\left[\boldsymbol{X}\vert Y\right]\right)$
applying a plug-in kernel-based algorithm to its entries. Next, we investigate
the estimators rate of convergence under smoothness hypotheses on the density
function of $(\boldsymbol{X},Y)$. In a high-dimensional context, we improve the
consistency the whole matrix estimator by providing a decreasing structure over
the $\mathrm{Cov}\left(\mathrm{E}\left[\boldsymbol{X}\vert Y\right]\right)$
entries. We illustrate a sliced inverse regression setting for time series
matching the conditions of our estimator


title: Tree Nash Equilibria in the Network Creation Game

abstract:
  In the network creation game with n vertices, every vertex (a player) buys a
set of adjacent edges, each at a fixed amount {\alpha} > 0. It has been
conjectured that for {\alpha} >= n, every Nash equilibrium is a tree, and has
been confirmed for every {\alpha} >= 273n. We improve upon this bound and show
that this is true for every {\alpha} >= 65n. To show this, we provide new and
improved results on the local structure of Nash equilibria. Technically, we
show that if there is a cycle in a Nash equilibrium, then {\alpha} < 65n.
Proving this, we only consider relatively simple strategy changes of the
players involved in the cycle. We further show that this simple approach cannot
be used to show the desired upper bound {\alpha} < n (for which a cycle may
exist), but conjecture that a slightly worse bound {\alpha} < 1.3n can be
achieved with this approach. Towards this conjecture, we show that if a Nash
equilibrium has a cycle of length at most 10, then indeed {\alpha} < 1.3n. We
further provide experimental evidence suggesting that when the girth of a Nash
equilibrium is increasing, the upper bound on {\alpha} obtained by the simple
strategy changes is not increasing. To the end, we investigate the approach for
a coalitional variant of Nash equilibrium, where coalitions of two players
cannot collectively improve, and show that if {\alpha} >= 41n, then every such
Nash equilibrium is a tree.


title:
Fixed points of the Similarity Renormalization Group and the Nuclear
  Many-Body Problem

abstract:
  The Similarity Renormalization Group reduces the off-shellness by driving the
evolved interaction towards a diagonal band. We analyze the infrared limit and
the corresponding on-shell interactions and its consequences for light nuclei.
Using a harmonic oscillator shell model we obtain a Tjon line B(4He)=
4B(3H)-3B(2H) which can be understood from a combinatorics counting of nucleon
pairs and triplets in the triton and alpha-particle and compares favorably with
realistic calculations.


title:
Clustering and decomposition for non BPS solutions of the
  $\mathbb{CP}^{N-1}$ models

abstract:
  We look at solutions (both BPS and non-BPS) of the $\mathbb{CP}^{N-1}$ model
on $\mathbb{R} \times S^1$ (with twisted boundary conditions), in particular by
using a conformal mapping technique, and we show how to interpret these
solutions by decomposing them into expressions describing constituent solitons.
We point out the problems that may arise (for non-BPS solutions) when one
naively looks at the clustering properties of these solutions. This could lead
to misunderstandings when studying extrapolations between small and large
compactification radii.


title:
Numerical Methods for Linear Diffusion Equations in the Presence of an
  Interface

abstract:
  We consider numerical methods for linear parabolic equations in one spatial
dimension having piecewise constant diffusion coefficients defined by a one
parameter family of interface conditions at the discontinuity. We construct
immersed interface finite element methods for an alternative formulation of the
original deterministic diffusion problem in which the interface condition is
recast as a natural condition on the interfacial flux for which the given
operator is self adjoint. An Euler-Maruyama method is developed for the
stochastic differential equation corresponding to the alternative divergence
formulation of the equation having a discontinuous coefficient and a
one-parameter family of interface conditions. We then prove convergence
estimates for the Euler scheme. The main goal is to develop numerical schemes
that can accommodate specification of any one of the possible interface
conditions, and to illustrate the implementation for each of the deterministic
and stochastic formulations, respectively. The issues pertaining to speed-ups
of the numerical schemes are left to future work.


title:
A differential equation for polynomials related to the Jacobian
  conjecture

abstract:
  We analyze a possible minimal counterexample to the Jacobian Conjecture $P,Q$
with $\gcd(deg(P),deg(Q))=16$ and show that its existence depends only on the
existence of solutions for a certain Abel differential equation of the second
kind.


title: N=1 Gribov superfield extension

abstract:
  We propose a mechanism displaying confinement, as defined by the behavior of
the propagators, for 4 dimensional, N = 1 supersymmetric Yang-Mills theory in
superfield formalism. In this work we intend to verify the possibility of
extending the known Gribov problem of quantization of Yang-Mills theories and
the implementation of a local action with auxiliary superfields like
Gribov-Zwanziger approach to this problem.


title: Constraints on Holographic cosmologies from strong lensing systems

abstract:
  We use strongly gravitationally lensed (SGL) systems to put additional
constraints on a set of holographic dark energy models. Data available in the
literature (redshift and velocity dispersion) is used to obtain the Einstein
radius and compare it with model predictions. We found that the LCDM is the
best fit to the data. Although a preliminary statistical analysis seems to
indicate that two of the holographic models studied show interesting agreement
with observations, a stringent test lead us to the result that neither of the
holographic models are competitive with the LCDM. These results highlight the
importance of Strong Lensing measurements to provide additional observational
constraints to alternative cosmological models, which are necessary to shed
some light into the dark universe.


title: On Strongly $F$-Regular Inversion of Adjunction

abstract:
  In this article we give two independent proofs of the positive characteristic
analog of the log terminal inversion of adjunction. We show that for a pair
$(X, S+B)$ in characteristic $p>0$, if $(S^n, B_{S^n})$ is strongly
$F$-regular, then $S$ is normal and $(X, S+B)$ is purely $F$-regular near $S$.
We also answer affirmatively an open question about the equality of
$F$-Different and Different.


title:
Three-Higgs-doublet models: symmetries, potentials and Higgs boson
  masses

abstract:
  We catalogue and study three-Higgs-doublet models in terms of all possible
allowed symmetries (continuous and discrete, Abelian and non-Abelian), where
such symmetries may be identified as flavour symmetries of quarks and leptons.
We analyse the potential in each case, and derive the conditions under which
the vacuum alignments (0,0,v), (0,v,v) and (v,v,v) are minima of the potential.
For the alignment (0,0,v), relevant for dark matter models, we calculate the
corresponding physical Higgs boson mass spectrum. Motivated by supersymmetry,
we extend the analysis to the case of three up-type Higgs doublets and three
down- type Higgs doublets (six doublets in total). Many of the results are also
applicable to flavon models where the three Higgs doublets are replaced by
three electroweak singlets.


title:
Relaxation of optically excited carriers in graphene: Anomalous
  diffusion and L\'evy flights

abstract:
  We present a theoretical analysis of the relaxation cascade of a photoexcited
electron in graphene in the presence of RPA screened electron-electron
interaction. We calculate the relaxation rate of high energy electrons and the
jump-size distribution of the random walk constituting the cascade which
exhibits fat tails. We find that the statistics of the entire cascade are
described by L\'evy flights with constant drift instead of standard
drift-diffusion in energy space. The L\'evy flight manifests nontrivial scaling
relations of the fluctuations in the cascade time, which is related to the
problem of the first passage time of L\'evy processes. Furthermore we determine
the transient differential transmission of graphene after an excitation by a
laser pulse taking into account the fractional kinetics of the relaxation
dynamics.


title: Bootstrapping the $\cN=1$ SCFT in three dimensions

abstract:
  We suggest a way to implement conformal bootstrap program for the case of the
${\cal N}=1$ SCFT in three dimensions using the previous analysis of the Ising
model in \cite{CB}. We find approximate values for the conformal dimensions of
several operators and the central charge $C_T$, the coefficient in the
two-point function of the stress-tensor. Bootstrapping this particular
(minimal) SCFT is of special interest as it was suggested in \cite{CM} that it
may realize supersymmetry in 2+1 dimensions in experiment. The values are in a
good agreement with the previous estimate in \cite{CM}.


title:
Substitution operators on the space of formal power series with a
  weighted cauchy product

abstract:
  Boundedness of $\diamond$-substitution operator $u\diamond C_\varphi$ on
$\ell^{p}(\beta)$, with a weighted Cauchy product $\diamond$, is investigated
by an inductive argument on the pair $(u, \varphi)$.


title: Dynamic correlations in Brownian many-body systems

abstract:
  For classical Brownian systems driven out of equilibrium we derive
inhomogeneous two-time correlation functions from functional differentiation of
the one-body density and current with respect to external fields. In order to
allow for appropriate freedom upon building the derivatives, we formally
supplement the Smoluchowski dynamics by a source term, which vanishes at the
physical solution. These techniques are applied to obtain a complete set of
dynamic Ornstein-Zernike equations, which serve for the development of
approximation schemes. The rules of functional calculus lead naturally to
non-Markovian equations of motion for the two-time correlators. Memory
functions are identified as functional derivatives of a unique space- and
time-nonlocal dissipation power functional.


title:
Enabling Information Centric Networks through Opportunistic Search,
  Routing and Caching

abstract:
  Content dissemination networks are pervasive in todays Internet. Examples of
content dissemination networks include peer-to-peer networks (P2P), content
distribution networks (CDN) and information centric networks (ICN). In this
paper, we propose a new system design for information centric networks which
leverages opportunistic searching, routing and caching. Our system design is
based on an hierarchical tiered structure. Random walks are used to find
content inside each tier, and gateways across tiers are used to direct requests
towards servers placed in the top tier, which are accessed in case content
replicas are not found in lower tiers. Then, we propose a model to analyze the
system in consideration. The model yields metrics such as mean time to find a
content and the load experienced by custodians as a function of the network
topology. Using the model, we identify trade-offs between these two metrics,
and numerically show how to find the optimal time to live of the random walks.


title:
Molecular excitation in the Interstellar Medium: recent advances in
  collisional, radiative and chemical processes

abstract: We review the different excitation processes in the interstellar medium


title:
The Newton tree: geometric interpretation and applications to the
  motivic zeta function and the log canonical threshold

abstract:
  Let I be an arbitrary ideal in C[[x,y]]. We use the Newton algorithm to
compute by induction the motivic zeta function of the ideal, yielding only few
poles, associated to the faces of the successive Newton polygons. We associate
a minimal Newton tree to I, related to using good coordinates in the Newton
algorithm, and show that it has a conceptual geometric interpretation in terms
of the log canonical model of I. We also compute the log canonical threshold
from a Newton polygon and strengthen Corti's inequalities.


title:
Quantum Storage of Heralded Single Photons in a Praseodymium Doped
  Crystal

abstract:
  We report on experiments demonstrating the reversible mapping of heralded
single photons to long lived collective optical atomic excitations stored in a
Pr$^{3+}$:Y$_2$SiO$_5$ crystal. A cavity-enhanced spontaneous down-conversion
source is employed to produce widely non-degenerate narrow-band ($\approx
2\,\mathrm{MHz}$) photon-pairs. The idler photons, whose frequency is
compatible with telecommunication optical fibers, are used to herald the
creation of the signal photons, compatible with the Pr$^{3+}$ transition. The
signal photons are stored and retrieved using the atomic frequency comb
protocol. We demonstrate storage times up to $4.5\,\mathrm{\mu s}$ while
preserving non-classical correlations between the heralding and the retrieved
photon. This is more than 20 times longer than in previous realizations in
solid state devices, and implemented in a system ideally suited for the
extension to spin-wave storage.


title:
Superfast non-linear diffusion: Capillary transport in particulate
  porous media

abstract:
  The migration of liquids in porous media, such as sand, has been commonly
considered at high saturation levels with liquid pathways at pore dimensions.
In this letter we reveal a low saturation regime observed in our experiments
with droplets of extremely low volatility liquids deposited on sand. In this
regime the liquid is mostly found within the grain surface roughness and in the
capillary bridges formed at the contacts between the grains. The bridges act as
variable-volume reservoirs and the flow is driven by the capillary pressure
arising at the wetting front according to the roughness length scales. We
propose that this migration (spreading) is the result of interplay between the
bridge volume adjustment to this pressure distribution and viscous losses of a
creeping flow within the roughness. The net macroscopic result is a special
case of non-linear diffusion described by a superfast diffusion equation (SFDE)
for saturation with distinctive mathematical character. We obtain solutions to
a moving boundary problem defined by SFDE that robustly convey a time power law
of spreading as seen in our experiments.


title: Conformal nets III: fusion of defects

abstract:
  Conformal nets provides a mathematical model for conformal field theory. We
define a notion of defect between conformal nets, formalizing the idea of an
interaction between two conformal field theories. We introduce an operation of
fusion of defects, and prove that the fusion of two defects is again a defect,
provided the fusion occurs over a conformal net of finite index. There is a
notion of sector (or bimodule) between two defects, and operations of
horizontal and vertical fusion of such sectors. Our most difficult technical
result is that the horizontal fusion of the vacuum sectors of two defects is
isomorphic to the vacuum sector of the fused defect. Equipped with this
isomorphism, we construct the basic interchange isomorphism between the
horizontal fusion of two vertical fusions and the vertical fusion of two
horizontal fusions of sectors.


title:
Modelling and simulation of adhesive curing processes in bonded piezo
  metal composites

abstract:
  This work deals with the modelling and simulation of curing phenomena in
adhesively bonded piezo metal composites which consist of an adhesive layer
with integrated piezoelectric module and two surrounding metal sheet layers. In
a first step, a general modelling framework is proposed which is able to
represent curing phenomena in polymers at finite strains. Based on this
formulation, a concretized model is deduced for the simulation of curing in one
specific epoxy based adhesive. Here, appropriate material functions are
specified and the thermodynamic consistency is proved. Regarding the finite
element implementation, a numerical integration scheme and a new approach for
the consideration of different initial conditions are provided. Finally, finite
element simulations of a newly proposed manufacturing process for the
production of bonded piezo metal composite structures are conducted. A deep
drawing process of the composite with uncured adhesive layer and the subsequent
adhesive curing are investigated.


title: String Black Holes as Particle Accelerators to Arbitrarily High Energy

abstract:
  We show that an extremal Gibbons-Maeda-Garfinkle-Horowitz-Strominger black
hole may act as a particle accelerator with arbitrarily high energy when two
uncharged particles falling freely from rest to infinity on the near horizon.
We show that the center of mass energy of collision independent of the extreme
fine tuning of the angular momentum of the colliding particles. We further show
that the center of mass energy of collisions of particles at the ISCO
($r_{ISCO}$) or at the photon orbit ($r_{ph}$) or at the marginally bound
circular orbit ($r_{mb}$) i.e. at $r \equiv r_{ISCO}=r_{ph}=r_{mb}=2M$ could be
arbitrarily large for the aforementioned spacetimes, which is different from
Schwarzschild and Reissner-Nordstr{\o}m spcetimes. For non-extremal GMGHS
spacetimes the CM energy is finite and depends upon the asymptotic value of the
dilation field ($\phi_{0}$).


title: Derived automorphism groups of K3 surfaces of Picard rank 1

abstract:
  We give a complete description of the group of exact autoequivalences of the
bounded derived category of coherent sheaves on a K3 surface of Picard rank 1.
We do this by proving that a distinguished connected component of the space of
stability conditions is preserved by all autoequivalences, and is contractible.


title:
Realization of Morphing Logic Gates in a Repressilator with Quorum
  Sensing Feedback

abstract:
  We demonstrate how a genetic ring oscillator network with quorum sensing
feedback can operate as a robust logic gate. Specifically we show how a range
of logic functions, namely AND/NAND, OR/NOR and XOR/XNOR, can be realized by
the system, thus yielding a versatile unit that can morph between different
logic operations. We further demonstrate the capacity of this system to yield
complementary logic operations in parallel. Our results then indicate the
computing potential of this biological system, and may lead to bio-inspired
computing devices.


title:
Cellular decision-making bias: the missing ingredient in cell functional
  diversity

abstract:
  Cell functional diversity is a significant determinant on how biological
processes unfold. Most accounts of diversity involve a search for sequence or
expression differences. Perhaps there are more subtle mechanisms at work. Using
the metaphor of information processing and decision-making might provide a
clearer view of these subtleties. Understanding adaptive and transformative
processes (such as cellular reprogramming) as a series of simple decisions
allows us to use a technique called cellular signal detection theory (cellular
SDT) to detect potential bias in mechanisms that favor one outcome over
another. We can apply method of detecting cellular reprogramming bias to
cellular reprogramming and other complex molecular processes. To demonstrate
scope of this method, we will critically examine differences between cell
phenotypes reprogrammed to muscle fiber and neuron phenotypes. In cases where
the signature of phenotypic bias is cryptic, signatures of genomic bias
(pre-existing and induced) may provide an alternative. The examination of these
alternates will be explored using data from a series of fibroblast cell lines
before cellular reprogramming (pre-existing) and differences between fractions
of cellular RNA for individual genes after drug treatment (induced). In
conclusion, the usefulness and limitations of this method and associated
analogies will be discussed.


title: Fourier transform of a Bessel function multiplied by a Gaussian

abstract:
  An analytical result is given for the exact evaluation of an integral which
arises in the analysis of acoustic radiation from wave packet sources:
  $
  I_{mn}(\beta,q) =
  \int_{-\infty}^{\infty}
  e^{-\beta^{2}x^{2}-i q x}x^{m+1/2}J_{n+1/2}(x)
  \,d x, $ where $m$ and $n$ are non-negative integers, and $J_{n+1/2}(\cdot)$
is a Bessel function of order $n+1/2$.


title:
Nonlinear Surface-Plasmon Whispering-Gallery Modes in Metallic Nanowire
  Cavities

abstract:
  We demonstrate that the surface second-harmonic generation can lead to the
formation of nonlinear plasmonic whispering-gallery modes (WGMs) in
microcavities made of metallic nanowires. Since these WGMs are excited by
induced surface nonlinear dipoles, they can be generated even when they are not
coupled to the radiation continuum. Consequently, the quality factor of these
nonlinear modes can be as large as the theoretical limit imposed by the optical
losses in the metal. Remarkably, our theoretical analysis shows that nonlinear
plasmonic WGMs are characterized by fractional azimuthal modal numbers. This
suggests that the plasmonic cavities investigated here can be used to generate
multi-color optical fields with fractional angular momentum. Applications to
plasmonic sensors are also discussed.


title:
Taylor coefficients of inner functions and Beurling's theorem for the
  shift

abstract:
  The purpose of this expository note is to give a proof of a Schur-type
theorem that characterizes the inner functions in terms of their Taylor
coefficients. In view of Beurling's theorem, this provides a sequential
characterization of the shift-invariant subspaces of $\ell^2$.


title:
Active Brownian agents with concentration-dependent chemotactic
  sensitivity

abstract:
  We study a biologically motivated model of overdamped, autochemotactic
Brownian agents with concentration-dependent chemotactic sensitivity. The
agents in our model move stochastically and produce a chemical ligand at their
current position. The ligand concentration obeys a reaction-diffusion equation
and acts as a chemoattractant for the agents, which bias their motion towards
higher concentrations of the dynamically altered chemical field. We explore the
impact of concentration-dependent response to chemoattractant gradients on
large-scale pattern formation, by deriving a coarse-grained macroscopic
description of the individual based model, and compare the conditions for
emergence of inhomogeneous solutions for different variants of the chemotactic
sensitivity. We focus primarily on the so-called "Receptor Law" sensitivity,
which models a non-linear decrease of chemotactic sensitivity with increasing
ligand concentration. Our results reveal qualitative differences between the
"Receptor-Law", the constant chemotactic response and the so-called "Log-Law",
with respect to stability of the homogeneous solution, as well as the emergence
of different patterns (labyrinthine structures, clusters and bubbles) via
spinodal-decomposition or nucleation. We discuss two limiting cases, where the
model can be reduced to the dynamics of single species: (I) the agent density
governed by an density-dependent effective diffusion coefficient and (II) the
ligand-field with an effective bistable, time-dependent reaction rate. In the
end, we turn to single clusters of agents, studying domain growth and
determining mean characteristics of the stationary inhomogeneous state.
Analytical results are confirmed and extended by large-scale GPU simulations of
the individual based model.


title: Jamming Percolation in Three Dimensions

abstract:
  We introduce a three-dimensional model for jamming and glasses, and prove
that the fraction of frozen particles is discontinuous at the
directed-percolation critical density. In agreement with the accepted scenario
for jamming- and glass-transitions, this is a mixed-order transition; the
discontinuity is accompanied by diverging length- and time-scales. Because
one-dimensional directed-percolation paths comprise the backbone of frozen
particles, the unfrozen rattlers may use the third dimension to travel between
their cages. Thus the dynamics are diffusive on long-times even above the
critical density for jamming.


title: Continuous Self Energy of Ions at the Dielectric Interface

abstract:
  We present a simple, unified theory for the self-energy of an ion near a
dielectric interface. Our theory accounts for both the short-range (solvation)
and long-range (image force) electrostatic forces, charge polarization induced
by these forces, and the cavity energy. In contrast to previous models, our
self energy is continuous across the interface and thus applicable to both the
water and air (oil) sides of the interface. With no fitting parameters, we
predict the specific ion effect on the interfacial affinity of halogen anions
at the water/air interface, and the strong adsorption of hydrophobic ions at
the water/oil interface, in agreement with experiments and atomistic
simulations.


title: Gyrotropic Birefringence in the Under-doped Cuprates

abstract:
  The optical effects due to the loop-current order parameter in under-doped
cuprates are studied in order to understand the recent observation of unusual
birefringence in electromagnetic propagation in under-doped cuprates. It is
shown why birefringence occurs even in multiple domains of order with size of
domains much smaller than the wave-length and in twinned samples. Not only is
there a rotation of polarization of incident light but also a rotation of the
principal optical axis from the crystalline axes. Both are calculated in
relative agreement with experiments in terms of the same parameters. The
magnitude of the effect is orders of magnitude larger than the unusual Kerr
effect observed in under-doped cuprates earlier. The new observations,
including their comparison with the Kerr effect, test the symmetry of the
proposed order decisively and confirm the conclusions from polarized neutron
scattering.


title: A Bound on Length Isospectral Families of Hyperbolic Surfaces

abstract:
  In this paper we obtain a bound on the number of isometry classes of finite
area hyperbolic surfaces which are length isospectral to a given surface
depending only on the topological type of the surface and the length of the
shortest closed geodesic on the surface. This will follow from a more general
bound applying to any family of hyperbolic surfaces which admits a Bers'
constant and with a lower bound on systole length.


title: On Number Representation

abstract:
  Place value numbers, such as the binary or decimal numbers can be represented
by the end vertices (leaf or pendant vertices) of rooted symmetrical trees.
Numbers that consist of at most a fixed number of digits are represented by
vertices that are equidistant from the root vertex and the corresponding number
representations do not depend on the distance from the root vertex. In this
paper, we introduce number systems that are representable by all vertices of a
rooted symmetric tree in such a way that the number representation of each
vertex depends on its distance from the root vertex.


title: Satisfiability Modulo ODEs

abstract:
  We study SMT problems over the reals containing ordinary differential
equations. They are important for formal verification of realistic hybrid
systems and embedded software. We develop delta-complete algorithms for SMT
formulas that are purely existentially quantified, as well as exists-forall
formulas whose universal quantification is restricted to the time variables. We
demonstrate scalability of the algorithms, as implemented in our open-source
solver dReal, on SMT benchmarks with several hundred nonlinear ODEs and
variables.


title: Homotopy coherent adjunctions and the formal theory of monads

abstract:
  In this paper, we introduce a cofibrant simplicial category that we call the
free homotopy coherent adjunction and characterize its n-arrows using a
graphical calculus that we develop here. The hom-spaces are appropriately
fibrant, indeed are nerves of categories, which indicates that all of the
expected coherence equations in each dimension are present. To justify our
terminology, we prove that any adjunction of quasi-categories extends to a
homotopy coherent adjunction and furthermore that these extensions are
homotopically unique in the sense that the relevant spaces of extensions are
contractible Kan complexes.
  We extract several simplicial functors from the free homotopy coherent
adjunction and show that quasi-categories are closed under weighted limits with
these weights. These weighted limits are used to define the homotopy coherent
monadic adjunction associated to a homotopy coherent monad. We show that each
vertex in the quasi-category of algebras for a homotopy coherent monad is a
codescent object of a canonical diagram of free algebras. To conclude, we prove
the quasi-categorical monadicity theorem, describing conditions under which the
canonical comparison functor from a homotopy coherent adjunction to the
associated monadic adjunction is an equivalence of quasi-categories. Our proofs
reveal that a mild variant of Beck's argument is "all in the weights" - much of
it independent of the quasi-categorical context.


title:
Solvable Group Representations and Free Divisors whose Complements are
  $K(\pi, 1)$'s

abstract:
  We apply previous results on the representations of solvable linear algebraic
groups to construct a new class of free divisors whose complements are $K(\pi,
1)$'s. These free divisors arise as the exceptional orbit varieties for a
special class of "block representations" and have the structure of
determinantal arrangements.
  Among these are the free divisors defined by conditions for the (modified)
Cholesky-type factorizations of matrices, which contain the determinantal
varieties of singular matrices of various types as components. These
complements are proven to be homotopy tori, as are the Milnor fibers of these
free divisors. The generators for the complex cohomology of each are given in
terms of forms defined using the basic relative invariants of the group
representation.


title:
A Measurement of the Millimeter Emission and the Sunyaev-Zel'dovich
  Effect Associated with Low-Frequency Radio Sources

abstract:
  We present a statistical analysis of the millimeter-wavelength properties of
1.4 GHz-selected sources and a detection of the Sunyaev-Zel'dovich (SZ) effect
associated with the halos that host them. The Atacama Cosmology Telescope (ACT)
has conducted a survey at 148 GHz, 218 GHz and 277 GHz along the celestial
equator. Using samples of radio sources selected at 1.4 GHz from FIRST and
NVSS, we measure the stacked 148, 218 and 277 GHz flux densities for sources
with 1.4 GHz flux densities ranging from 5 to 200 mJy. At these flux densities,
the radio source population is dominated by active galactic nuclei (AGN), with
both steep and flat spectrum populations, which have combined
radio-to-millimeter spectral indices ranging from 0.5 to 0.95, reflecting the
prevalence of steep spectrum sources at high flux densities and the presence of
flat spectrum sources at lower flux densities. The thermal SZ effect associated
with the halos that host the AGN is detected at the 5$\sigma$ level through its
spectral signature. When we compare the SZ effect with weak lensing
measurements of radio galaxies, we find that the relation between the two is
consistent with that measured by Planck for local bright galaxies. We present a
detection of the SZ effect in some of the lowest mass halos (average
$M_{200}\approx10^{13}$M$_{\odot}h_{70}^{-1}$) studied to date. This detection
is particularly important in the context of galaxy evolution models, as it
confirms that galaxies with radio AGN also typically support hot gaseous halos.
With Herschel observations, we show that the SZ detection is not significantly
contaminated by dust. We show that 5 mJy$<S_{1.4}<$200 mJy radio sources
contribute $\ell(\ell+1)C_{\ell}/(2\pi)=0.37\pm0.03\mu$K$^2$ to the angular
power spectrum at $\ell=3000$ at 148 GHz, after accounting for the SZ effect
associated with their host halos.


title:
Regularization of the spectral singularity in $\mathcal{PT}$-symmetric
  systems by all order nonlinearities: Nonreciprocity and optical isolation

abstract:
  Spectral singularities are ubiquitous with PT-symmetry leading to infinite
transmission and reflection coefficients. Such infinities imply the divergence
of the fields in the medium thereby breaking the very assumption of the
linearity of the medium used to obtain such singularities. We identify
saturable nonlinearity retaining contributions from all orders of the field to
limit the infinite growth and regularize the spectral singularity. We present
explicit numerical results to demonstrate regularization. The all order
nonlinear PT-symmetric device is shown to exhibit very effective isolation or
optical diode action, since transmission through such a system is
nonreciprocal. In contrast, a linear system or a system with Kerr nonlinearity
is known to have only reciprocal transmission. Further we demonstrate optical
bistability for such a system with high contrast.


title:
Comment on "Field-driven phase transitions in a quasi-two-dimensional
  quantum antiferromagnet"

abstract:
  In a recent publication [M. B. Stone et al., New Journal of Physics 9, 31
(2007)] a "Renormalized Classical 2D" (RC) phase has been reported in a
quasi-two-dimensional quantum antiferromagnet PHCC. Its key signature is a
sharp cusp-like feature in the magnetic susceptibility which appears below the
critical field of magnetic ordering indicated by specific heat anomaly and
emergence of a Bragg peak. Here we present experimental data which shows that
regardless of experimental geometry, the specific heat and susceptibility
anomalies in PHCC both coincide with the onset of true long range order. This
leaves no room for any additional intermediate "RC" phase.


title: An Effective Field Theory for the Spinless p-wave Superconductor

abstract:
  We construct effective field theories for superconductors, that are powerful
enough to describe low lying sub gap fermion modes localized to vortex cores,
and at the same time resemble topological field theories in that there are no
bulk degrees of freedom. This is achieved by a kinetic term for fermions that
is proportional to the vortex topological charge, and thus vanish in the bulk.
We study the case of a spin-less two-dimensional $p_x + ip_y$ superconductor in
some detail, and show that the the subgap fermionic spectrum in a single
vortex, including the zero mode, has the same features as those obtained from
microscopic models. We also show, that in the topological scaling limit our
theory becomes a bona fide topological field theory which retains the Majorana
modes at the vortex cores, and correctly describes the non-Abelian statistics
of such vortices.


title:
Multifield Inflation after Planck: Isocurvature Modes from Nonminimal
  Couplings

abstract:
  Recent measurements by the {\it Planck} experiment of the power spectrum of
temperature anisotropies in the cosmic microwave background radiation (CMB)
reveal a deficit of power in low multipoles compared to the predictions from
best-fit $\Lambda$CDM cosmology. The low-$\ell$ anomaly may be explained by the
presence of primordial isocurvature perturbations in addition to the usual
adiabatic spectrum, and hence may provide the first robust evidence that
early-universe inflation involved more than one scalar field. In this paper we
explore the production of isocurvature perturbations in nonminimally coupled
two-field inflation. We find that this class of models readily produces enough
power in the isocurvature modes to account for the \emph{Planck} low-$\ell$
anomaly, while also providing excellent agreement with the other {\it Planck}
results.


title:
System-size dependence of open-heavy-flavor production in
  nucleus-nucleus collisions at $\sqrt{s_{_{NN}}}$=200 GeV

abstract:
  The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured
open heavy flavor production in Cu$+$Cu collisions at $\sqrt{s_{_{NN}}}$=200
GeV through the measurement of electrons at midrapidity that originate from
semileptonic decays of charm and bottom hadrons. In peripheral Cu$+$Cu
collisions an enhanced production of electrons is observed relative to
$p$$+$$p$ collisions scaled by the number of binary collisions. In the
transverse momentum range from 1 to 5 GeV/$c$ the nuclear modification factor
is $R_{AA}$$\sim$1.4. As the system size increases to more central Cu$+$Cu
collisions, the enhancement gradually disappears and turns into a suppression.
For $p_T>3$ GeV/$c$, the suppression reaches $R_{AA}$$\sim$0.8 in the most
central collisions. The $p_T$ and centrality dependence of $R_{AA}$ in Cu$+$Cu
collisions agree quantitatively with $R_{AA}$ in $d+$Au and Au$+$Au collisions,
if compared at similar number of participating nucleons $\langle N_{\rm part}
\rangle$.


title:
Fermi-LAT Detection of a Break in the Gamma-Ray Spectrum of the
  Supernova Remnant Cassiopeia A

abstract:
  We report on observations of the supernova remnant Cassiopeia A in the energy
range from 100 MeV to 100 GeV using 44 months of observations from the Large
Area Telescope on board the Fermi Gamma-ray Space Telescope. We perform a
detailed spectral analysis of this source and report on a low-energy break in
the spectrum at $1.72^{+1.35}_{-0.89}$ GeV. By comparing the results with
models for the gamma-ray emission, we find that hadronic emission is preferred
for the GeV energy range.


title: Systematic parameter errors in inspiraling neutron star binaries

abstract:
  The coalescence of two neutron stars is an important gravitational wave
source for LIGO and other detectors. Numerous studies have considered the
precision with which binary parameters (masses, spins, Love numbers) can be
measured. Here I consider the accuracy with which these parameters can be
determined in the presence of systematic errors due to waveform approximations.
These approximations include truncation of the post-Newtonian (PN) series and
neglect of neutron star (NS) spin, tidal deformation, or orbital eccentricity.
All of these effects can yield systematic errors that exceed statistical errors
for plausible parameter values. In particular, neglecting spin, eccentricity,
or high-order PN terms causes a significant bias in the NS Love number. Tidal
effects will not be measurable with PN inspiral waveforms if these systematic
errors are not controlled.


title: Physical factorisation scheme for PDFs for non-inclusive applications

abstract:
  We introduce the physical factorisation scheme, which is necessary to
describe observables which are `not completely inclusive'. We derive the
formulae for NLO DGLAP evolution in this scheme, and also for the `rotation' of
the conventional MSbar PDFs into the physical representation. Unlike, the MSbar
prescription, where, for example, the gluon PDF at NLO obtains an admixture of
the quark-singlet PDF, and vice-versa, the physical approach does not mix
parton PDFs of different types. That is, the physical approach retains the
precise quantum numbers of each PDF. The NLO corrections to DGLAP evolution in
the physical scheme are less than those in the MSbar case, indicating a better
convergence of the perturbative series.


title: Gravitational wave signatures in black-hole-forming core collapse

abstract:
  We present numerical simulations in general relativity of collapsing stellar
cores. Our initial model consists of a low metallicity rapidly-rotating
progenitor which is evolved in axisymmetry with the latest version of our
general relativistic code CoCoNuT, which allows for black hole formation and
includes the effects of a microphysical equation of state (LS220) and a
neutrino leakage scheme to account for radiative losses. The motivation of our
study is to analyze in detail the emission of gravitational waves in the
collapsar scenario of long gamma-ray bursts. Our simulations show that the
phase during which the proto-neutron star (PNS) survives before ultimately
collapsing to a black hole is particularly optimal for gravitational wave
emission. The high-amplitude waves last for several seconds and show a
remarkable quasi-periodicity associated with the violent PNS dynamics, namely
during the episodes of convection and the subsequent nonlinear development of
the standing-accretion shock instability (SASI). By analyzing the spectrogram
of our simulations we are able to identify the frequencies associated with the
presence of g-modes and with the SASI motions at the PNS surface. We note that
the gravitational waves emitted reach large enough amplitudes to be detected
with third-generation detectors as the Einstein Telescope within a Virgo
cluster volume at rates ~< 0.1 /y.


title: Symmetry-protected many-body Aharonov-Bohm effect

abstract:
  It is known as a purely quantum effect that a magnetic flux affects the real
physics of a particle, such as the energy spectrum, even if the flux does not
interfere with the particle's path - the Aharonov-Bohm effect. Here we examine
an Aharonov-Bohm effect on a many-body wavefunction. Specifically, we study
this many-body effect on the gapless edge states of a bulk gapped phase
protected by a global symmetry (such as $\mathbb{Z}_{N}$) - the
symmetry-protected topological (SPT) states. The many-body analogue of spectral
shifts, the twisted wavefunction and the twisted boundary realization are
identified in this SPT state. An explicit lattice construction of SPT edge
states is derived, and a challenge of gauging its non-onsite symmetry is
overcome. Agreement is found in the twisted spectrum between a numerical
lattice calculation and a conformal field theory prediction.

categories: quant-ph cond-mat.mes-hall cond-mat.str-el hep-th


title:
On Elementary Methods To Evaluate Values of The Riemann Zeta Function
  and Another Closely Related Infinite Series At Natural Numbers

abstract:
  In this paper, an elementary method to find the values of the Riemann Zeta
function at even natural numbers, and to find values of a closely related
series at odd natural numbers is presented. Another method, specifically for
the evaluation of $\zeta(2),$ is also presented.