title: Microscopic Picture of Non-Relativistic Classicalons

abstract:
  A theory of a non-relativistic, complex scalar field with derivatively
coupled interaction terms is investigated. This toy model is considered as a
prototype of a classicalizing theory and in particular of general relativity,
for which the black hole constitutes a prominent example of a classicalon.
Accordingly, the theory allows for a non-trivial solution of the stationary
Gross-Pitaevskii equation corresponding to a black hole in the case of GR.
Quantum fluctuations on this classical background are investigated within the
Bogoliubov approximation. It turns out that the perturbative approach is
invalidated by a high occupation of the Bogoliubov modes. Recently, it was
proposed that a black hole is a Bose-Einstein condensate of gravitons that
dynamically ensures to stay at the verge of a quantum phase transition. Our
result is understood as an indication for that claim. Furthermore, it motivates
a non-linear numerical analysis of the model.


title:
A Case Study of the Arbitrariness of the h-Index and the
  Highly-Cited-Publications Indicator

abstract:
  The arbitrariness of the h-index becomes evident, when one requires q*h
instead of h citations as the threshold for the definition of the index, thus
changing the size of the core of the most influential publications of a
dataset. I analyze the citation records of 26 physicists in order to determine
how much the prefactor q influences the ranking. Likewise, the arbitrariness of
the highly-cited-publications indicator is due to the threshold value, given
either as an absolute number of citations or as a percentage of highly cited
papers. The analysis of the 26 citation records shows that the changes in the
rankings in dependence on these thresholds are rather large and comparable with
the respective changes for the h-index.


title:
A note on closed-form representation of Fibonacci numbers using
  Fibonacci trees

abstract:
  In this paper, we give a new representation of the Fibonacci numbers. This is
achieved using Fibonacci trees. With the help of this representation, the nth
Fibonacci number can be calculated without having any knowledge about the
previous Fibonacci numbers.


title: Variational Algorithms for Marginal MAP

abstract:
  The marginal maximum a posteriori probability (MAP) estimation problem, which
calculates the mode of the marginal posterior distribution of a subset of
variables with the remaining variables marginalized, is an important inference
problem in many models, such as those with hidden variables or uncertain
parameters. Unfortunately, marginal MAP can be NP-hard even on trees, and has
attracted less attention in the literature compared to the joint MAP
(maximization) and marginalization problems. We derive a general dual
representation for marginal MAP that naturally integrates the marginalization
and maximization operations into a joint variational optimization problem,
making it possible to easily extend most or all variational-based algorithms to
marginal MAP. In particular, we derive a set of "mixed-product" message passing
algorithms for marginal MAP, whose form is a hybrid of max-product, sum-product
and a novel "argmax-product" message updates. We also derive a class of
convergent algorithms based on proximal point methods, including one that
transforms the marginal MAP problem into a sequence of standard marginalization
problems. Theoretically, we provide guarantees under which our algorithms give
globally or locally optimal solutions, and provide novel upper bounds on the
optimal objectives. Empirically, we demonstrate that our algorithms
significantly outperform the existing approaches, including a state-of-the-art
algorithm based on local search methods.


title:
Discovery of new roAp pulsators in the UVES survey of cool magnetic Ap
  stars

abstract:
  We have carried out a survey of short-period pulsations among a sample of
carefully chosen cool Ap stars using time-resolved observations with the UVES
spectrometer at the ESO 8-m VLT telescope. Here we report the discovery of
pulsations with amplitudes 50-100 m/s and periods 7-12 min in HD132205,
HD148593 and HD151860. These objects are therefore established as new rapidly
oscillating Ap (roAp) stars. In addition, we independently confirm the presence
of pulsations in HD69013, HD96237 and HD143487 and detect, for the first time,
radial velocity oscillations in two previously known photometric roAp stars
HD119027 and HD185256. At the same time, no pulsation variability is found for
HD5823, HD178892 and HD185204. All of the newly discovered roAp stars were
previously classified as non-pulsating based on the low-precision ground-based
photometric surveys. This shows that such observations cannot be used to
reliably distinguish between pulsating and non-pulsating stars and that all
cool Ap stars may harbor p-mode pulsations of different amplitudes.


title: General Relativity and the Cuprates

abstract:
  We add a periodic potential to the simplest gravitational model of a
superconductor and compute the optical conductivity. In addition to a
superfluid component, we find a normal component that has Drude behavior at low
frequency followed by a power law fall-off. Both the exponent and coefficient
of the power law are temperature independent and agree with earlier results
computed above $T_c$. These results are in striking agreement with measurements
on some cuprates. We also find a gap $\Delta = 4.0\ T_c$, a rapidly decreasing
scattering rate, and "missing spectral weight" at low frequency, all of which
also agree with experiments.


title: Naturalness and the Status of Supersymmetry

abstract:
  For decades, the unnaturalness of the weak scale has been the dominant
problem motivating new particle physics, and weak-scale supersymmetry has been
the dominant proposed solution. This paradigm is now being challenged by a
wealth of experimental data. In this review, we begin by recalling the
theoretical motivations for weak-scale supersymmetry, including the gauge
hierarchy problem, grand unification, and WIMP dark matter, and their
implications for superpartner masses. These are set against the leading
constraints on supersymmetry from collider searches, the Higgs boson mass, and
low-energy constraints on flavor and CP violation. We then critically examine
attempts to quantify naturalness in supersymmetry, stressing the many
subjective choices that impact the results both quantitatively and
qualitatively. Finally, we survey various proposals for natural supersymmetric
models, including effective supersymmetry, focus point supersymmetry,
compressed supersymmetry, and R-parity-violating supersymmetry, and summarize
their key features, current status, and implications for future experiments.


title: Intrinsic uncertainty on the nature of dark energy

abstract:
  We argue that there is an intrinsic noise on measurements of the equation of
state parameter $w=p/\rho$ from large-scale structure around us. The presence
of the large-scale structure leads to an ambiguity in the definition of the
background universe and thus there is a maximal precision with which we can
determine the equation of state of dark energy. To study the uncertainty due to
local structure, we model density perturbations stemming from a standard
inflationary power spectrum by means of the exact Lema\^{i}tre-Tolman-Bondi
solution of Einstein's equation, and show that the usual distribution of matter
inhomogeneities in a $\Lambda$CDM cosmology causes a variation of $w$ -- as
inferred from distance measures -- of several percent. As we observe only one
universe, or equivalently because of the cosmic variance, this uncertainty is
systematic in nature.


title:
Two Emission Mechanisms in the Fermi Bubbles: A Possible Signal of
  Annihilating Dark Matter

abstract:
  We study the variation of the spectrum of the Fermi Bubbles with Galactic
latitude. Far from the Galactic plane (|b| > 30 degrees), the observed
gamma-ray emission is nearly invariant with latitude, and is consistent with
arising from inverse Compton scattering of the interstellar radiation field by
cosmic-ray electrons with an approximately power-law spectrum. The same
electrons in the presence of microgauss-scale magnetic fields can also generate
the the observed microwave "haze". At lower latitudes (b < 20 degrees), in
contrast, the spectrum of the emission correlated with the Bubbles possesses a
pronounced spectral feature peaking at 1-4 GeV (in E^2 dN/dE) which cannot be
generated by any realistic spectrum of electrons. Instead, we conclude that a
second (non-inverse-Compton) emission mechanism must be responsible for the
bulk of the low-energy, low-latitude emission. This second component is
spectrally similar to the excess GeV emission previously reported from the
Galactic Center (GC), and also appears spatially consistent with a luminosity
per volume falling approximately as r^-2.4, where r is the distance from the
GC. We argue that the spectral feature visible in the low-latitude Bubbles is
the extended counterpart of the GC excess, now detected out to at least 2-3 kpc
from the GC. The spectrum and angular distribution of the signal is consistent
with that predicted from ~10 GeV dark matter particles annihilating to leptons,
or from ~50 GeV dark matter particles annihilating to quarks, following a
distribution similar to the canonical Navarro-Frenk-White (NFW) profile. We
also consider millisecond pulsars as a possible astrophysical explanation for
the signal, as observed millisecond pulsars possess a spectral cutoff at
approximately the required energy. Any such scenario would require a large
population of unresolved millisecond pulsars extending at least 2-3 kpc from
the GC.


title: A kinematic study of the Andromeda dwarf spheroidal system

abstract:
  We present a homogeneous kinematic analysis of red giant branch stars within
18 of the 28 Andromeda dwarf spheroidal (dSph) galaxies, obtained using the
Keck I LRIS and Keck II DEIMOS spectrographs. Based on their g-i colors (taken
with the CFHT MegaCam imager), physical positions on the sky, and radial
velocities, we assign probabilities of dSph membership to each observed star.
Using this information, the velocity dispersions, central masses and central
densities of the dark matter halos are calculated for these objects, and
compared with the properties of the Milky Way dSph population. We also measure
the average metallicity ([Fe/H]) from the co-added spectra of member stars for
each M31 dSph and find that they are consistent with the trend of decreasing
[Fe/H] with luminosity observed in the Milky Way population. We find that three
of our studied M31 dSphs appear as significant outliers in terms of their
central velocity dispersion, And XIX, XXI and XXV, all of which have large
half-light radii (>700 pc) and low velocity dispersions (sigma_v<5 km/s). In
addition, And XXV has a mass-to-light ratio within its half-light radius of
just [M/L]_{half}=10.3^{+7.0}_{-6.7}, making it consistent with a simple
stellar system with no appreciable dark matter component within its 1 sigma
uncertainties. We suggest that the structure of the dark matter halos of these
outliers have been significantly altered by tides.


title:
The Galactic Center Cloud G2 -- a Young Low-Mass Star with a Stellar
  Wind

abstract:
  We explore the possibility that the G2 gas cloud falling in towards \sgra is
the mass loss envelope of a young TTauri star. As the star plunges to smaller
radius at 1000 to 6000 \kms, a strong bow shock forms where the stellar wind is
impacted by the hot X-ray emitting gas in the vicinity of \sgra. For a stellar
mass loss rate of $4\times10^{-8}$ \msun per yr and wind velocity 100 \kms, the
bow shock will have an emission measure ($EM = n^2 vol$) at a distance
$\sim10^{16}$ cm, similar to that inferred from the IR emission lines. The
ionization of the dense bow shock gas is potentially provided by collisional
ionization at the shock front and cooling radiation (X-ray and UV) from the
post shock gas. The former would predict a constant line flux as a function of
distance from \sgra, while the latter will have increasing emission at lesser
distances. In this model, the star and its mass loss wind should survive
pericenter passage since the wind is likely launched at 0.2 AU and this is much
less than the Roche radius at pericenter ($\sim3$ AU for a stellar mass of
2\msun). In this model, the emission cloud will probably survive pericenter
passage, discriminating this scenario from others.


abstract:
  The Next Generation Transit Survey (NGTS) is a new ground-based sky survey
designed to find transiting Neptunes and super-Earths. By covering at least
sixteen times the sky area of Kepler we will find small planets around stars
that are sufficiently bright for radial velocity confirmation, mass
determination and atmospheric characterisation. The NGTS instrument will
consist of an array of twelve independently pointed 20cm telescopes fitted with
red-sensitive CCD cameras. It will be constructed at the ESO Paranal
Observatory, thereby benefiting from the very best photometric conditions as
well as follow up synergy with the VLT and E-ELT. Our design has been verified
through the operation of two prototype instruments, demonstrating white noise
characteristics to sub-mmag photometric precision. Detailed simulations show
that about thirty bright super-Earths and up to two hundred Neptunes could be
discovered. Our science operations are due to begin in 2014.


title: Supersymmetric Boundary Conditions in Three Dimensional N = 2 Theories

abstract:
  We study supersymmetric boundary conditions in 3-dimensional N = 2
Landau-Ginzburg models and abelian gauge theories. In the Landau-Ginzburg model
the boundary conditions that preserve (1,1) supersymmetry (A-type) and (2,0)
supersymmetry (B-type) on the boundary are classified in terms of subspaces of
the target space ("brane"). An A-type brane is a Lagrangian submanifold on
which the imaginary part of the superpotential is constant, while a B-type
brane is a holomorphic submanifold on which the superpotential is constant. We
also consider the N = 2 Maxwell theory with boundary and the abelian duality.
Finally we make some comments on N = 2 SQED with boundary condition and the
mirror symmetry.


title: The Distribution of Alpha Elements in Ultra-Faint Dwarf Galaxies

abstract:
  The Milky Way ultra-faint dwarf galaxies (UFDs) contain some of the oldest,
most metal-poor stars in the Universe. We present [Mg/Fe], [Si/Fe], [Ca/Fe],
[Ti/Fe], and mean [alpha/Fe], abundance ratios for 61 individual red giant
branch stars across 8 UFDs. This is the largest sample of alpha abundances
published to date in galaxies with absolute magnitudes M_V > -8, including the
first measurements for Segue 1, Canes Venatici II, Ursa Major I, and Leo T.
Abundances were determined via medium-resolution Keck/DEIMOS spectroscopy and
spectral synthesis. The sample spans the metallicity range -3.4 < [Fe/H] <
-1.1. With the possible exception of Segue 1 and Ursa Major II, the individual
UFDs show on average lower [alpha/Fe] at higher metallicities, consistent with
enrichment from Type Ia supernovae. Thus even the faintest galaxies have
undergone at least a limited level of chemical self-enrichment. Together with
recent photometric studies, this suggests that star formation in the UFDs was
not a single burst, but instead lasted at least as much as the minimum time
delay of the onset of Type Ia supernovae (~100 Myr) and less than ~2 Gyr. We
further show that the combined population of UFDs has an [alpha/Fe] abundance
pattern that is inconsistent with a flat, Galactic halo-like alpha abundance
trend, and is also qualitatively different from that of the more luminous CVn I
dSph, which does show a hint of a plateau at very low [Fe/H].


title:
Combining Multiple Time Series Models Through A Robust Weighted
  Mechanism

abstract:
  Improvement of time series forecasting accuracy through combining multiple
models is an important as well as a dynamic area of research. As a result,
various forecasts combination methods have been developed in literature.
However, most of them are based on simple linear ensemble strategies and hence
ignore the possible relationships between two or more participating models. In
this paper, we propose a robust weighted nonlinear ensemble technique which
considers the individual forecasts from different models as well as the
correlations among them while combining. The proposed ensemble is constructed
using three well-known forecasting models and is tested for three real-world
time series. A comparison is made among the proposed scheme and three other
widely used linear combination methods, in terms of the obtained forecast
errors. This comparison shows that our ensemble scheme provides significantly
lower forecast errors than each individual model as well as each of the four
linear combination methods.


title:
Quantum Simulation Architecture for Lattice Bosons in Arbitrary, Tunable
  External Gauge Fields

abstract:
  We describe a lattice of asymmetrical qubit pairs in one or two dimensions,
with couplings arranged so that the motion of single-qubit excited states
mimics the behavior of charged lattice bosons hopping in a magnetic field. We
show in particular that one can choose the parameters of the many-body circuit
to reach a regime where the complex hopping phase between any two elements can
be tuned to any value by simply adjusting the relative phases of two applied
oscillating voltage signals. We also propose a specific realization of our
model using coupled three junction flux qubits, in which one can reach the
strongly interacting bosonic quantum Hall limit where one will find anyonic
excitations. The circuits could be used for topological quantum computation.

categories: cond-mat.str-el cond-mat.mes-hall cond-mat.supr-con quant-ph


title: Independence of l-adic representations of geometric Galois groups

abstract:
  Let k be an algebraically closed field of arbitrary characteristic,let K/k be
a finitely generated field extension and let X be a separated scheme of finite
type over K. For each prime ell, the absolute Galois group of K acts on the
ell-adic etale cohomology modules of X. We prove that this family of
representations varying over ell is almost independent in the sense of Serre,
i.e., that the fixed fields inside an algebraic closure of K of the kernels of
the representations for all ell become linearly disjoint over a finite
extension of K. In doing this, we also prove a number of interesting facts on
the images and ramification of this family of representations.


title:
The Snapshot Hubble U-Band Cluster Survey (SHUCS). I. Survey Description
  and First Application to the Mixed Star Cluster Population of NGC 4041

abstract:
  We present the Snapshot Hubble U-band Cluster Survey (SHUCS), a project aimed
at characterizing the star cluster populations of ten nearby galaxies (d<23
Mpc, half within 12 Mpc) through new F336W (U band equivalent) imaging from
WFC3, and archival BVI-equivalent data with HST. Completing the UBVI baseline
reduces the age-extinction degeneracy of optical colours, thus enabling the
measurement of reliable ages and masses for the thousands of clusters covered
by our survey. The sample consists chiefly of face-on spiral galaxies at low
inclination, in various degrees of isolation (isolated, in group, merging), and
includes two AGN hosts. This first paper outlines the survey itself, the
observational datasets, the analysis methods, and presents a proof-of-concept
study of the large-scale properties and star cluster population of NGC 4041, a
massive SAbc galaxy at a distance of 23 Mpc, and part of a small grouping of
six giant members. We resolve two structural components with distinct stellar
populations, a morphology more akin to merging and interacting systems. We also
find strong evidence of a truncated, Schechter-type mass function, and a
similarly segmented luminosity function. These results indicate that binning
must erase much of the substructure present in the mass and luminosity
functions, and might account for the conflicting reports on the intrinsic shape
of these functions in the literature. We also note a tidal feature in the
outskirts of the galaxy in GALEX UV imaging, and follow it up with a
comprehensive multi-wavelength study of NGC 4041 and its parent group. We
deduce a minor merger as a likely cause of its segmented structure and the
observed pattern of a radially decreasing star formation rate. We propose that
combining the study of star cluster populations with broad-band metrics is not
only advantageous, but often easily achievable through archival datasets.


title: Poisson summation formula and Box splines

abstract:
  We generalize Dahmen-Micchelli deconvolution formula for Box splines with
parameters. Our proof is based on identities for Poisson summation of rational
functions with poles on hyperplanes.


title: Opto-thermal analysis of a lightweighted mirror for solar telescope

abstract:
  In this paper, an opto-thermal analysis of a moderately heated lightweighted
solar telescope mirror is carried out using 3D finite element analysis (FEA). A
physically realistic heat transfer model is developed to account for the
radiative heating and energy exchange of the mirror with surroundings. The
numerical simulations show the non-uniform temperature distribution and
associated thermo-elastic distortions of the mirror blank clearly mimicking the
underlying discrete geometry of the lightweighted substrate. The computed
mechanical deformation data is analyzed with surface polynomials and the
optical quality of the mirror is evaluated with the help of a ray-tracing
software. The thermal print-through distortions are further shown to contribute
to optical figure changes and mid-spatial frequency errors of the mirror
surface. A comparative study presented for three commonly used substrate
materials, namely, Zerodur, Pyrex and Silicon Carbide (SiC) is relevant to vast
area of large optics requirements in ground and space applications.


title:
Finite size source effects and the correlation of neutrino transition
  probabilities through supernova turbulence

abstract:
  (Abridged) The transition probabilities describing the evolution of a
neutrino with a given energy along some ray through a turbulent supernova are
random variates unique to each ray. If the source of the neutrinos were a point
then all neutrinos of a given energy and emitted at the same time which were
detected in some far off location would have seen the same turbulent profile
therefore their transition probabilities would be exactly correlated. But if
the source has a finite size then the profiles seen by neutrinos emitted from
different points at the source will have seen different turbulence and the
correlation of the transition probabilities will be reduced. In this paper we
study the correlation of the neutrino transition probabilities through
turbulent supernova profiles as a function of the separation between the
emission points using an isotropic and an anisotropic power spectrum for the
random field used to model the turbulence. The spectral features in the high
density resonance mixing channel of the next Galactic supernova neutrino burst
may be strongly obscured by large amplitude turbulence when it enters the
signal due to the finite size of the source while the presence of features in
the low density and non resonant mixing channels may persist, the exact amount
depending upon the degree of anisotropy of the turbulence.


title:
Using Modified Partitioning Around Medoids Clustering Technique in
  Mobile Network Planning

abstract:
  Every cellular network deployment requires planning and optimization in order
to provide adequate coverage, capacity, and quality of service (QoS).
Optimization mobile radio network planning is a very complex task, as many
aspects must be taken into account. With the rapid development in mobile
network we need effective network planning tool to satisfy the need of
customers. However, deciding upon the optimum placement for the base stations
(BS s) to achieve best services while reducing the cost is a complex task
requiring vast computational resource. This paper introduces the spatial
clustering to solve the Mobile Networking Planning problem. It addresses
antenna placement problem or the cell planning problem, involves locating and
configuring infrastructure for mobile networks by modified the original
Partitioning Around Medoids PAM algorithm. M-PAM (Modified Partitioning Around
Medoids) has been proposed to satisfy the requirements and constraints. PAM
needs to specify number of clusters (k) before starting to search for the best
locations of base stations. The M-PAM algorithm uses the radio network planning
to determine k. We calculate for each cluster its coverage and capacity and
determine if they satisfy the mobile requirements, if not we will increase (k)
and reapply algorithms depending on two methods for clustering. Implementation
of this algorithm to a real case study is presented. Experimental results and
analysis indicate that the M-PAM algorithm when applying method two is
effective in case of heavy load distribution, and leads to minimum number of
base stations, which directly affected onto the cost of planning the network.


title:
Photochemistry in Terrestrial Exoplanet Atmospheres II: H2S and SO2
  Photochemistry in Anoxic Atmospheres

abstract:
  Sulfur gases are common components in the volcanic and biological emission on
Earth, and are expected to be important input gases for atmospheres on
terrestrial exoplanets. We study the atmospheric composition and the spectra of
terrestrial exoplanets with sulfur compounds (i.e., H2S and SO2) emitted from
their surfaces. We use a comprehensive one-dimensional photochemistry model and
radiative transfer model to investigate the sulfur chemistry in atmospheres
ranging from reducing to oxidizing. The most important finding is that both H2S
and SO2 are chemically short-lived in virtually all types of atmospheres on
terrestrial exoplanets, based on models of H2, N2, and CO2 atmospheres. This
implies that direct detection of surface sulfur emission is unlikely, as their
surface emission rates need to be extremely high (>1000 times Earth's volcanic
sulfur emission) for these gases to build up to a detectable level. We also
find that sulfur compounds emitted from the surface lead to photochemical
formation of elemental sulfur and sulfuric acid in the atmosphere, which would
condense to form aerosols if saturated. For terrestrial exoplanets in the
habitable zone of Sun-like stars or M stars, Earth-like sulfur emission rates
result in optically thick haze composed of elemental sulfur in reducing
H2-dominated atmospheres for a wide range of particle diameters (0.1-1 micron),
which is assumed as a free parameter in our simulations. In oxidized
atmospheres composed of N2 and CO2, optically thick haze, composed of elemental
sulfur aerosols (S8) or sulfuric acid aerosols (H2SO4), will form if the
surface sulfur emission is 2 orders of magnitude more than the volcanic sulfur
emission of Earth. Although direct detection of H2S and SO2 by their spectral
features is unlikely, their emission might be inferred by observing
aerosol-related features in reflected light with future generation space
telescopes.


title:
Ultrafast plasmonics using transparent conductive oxide hybrids in the
  epsilon near-zero regime

abstract:
  The dielectric response of transparent conductive oxides near the bulk
plasmon frequency is characterized by a refractive index less than vacuum. In
analogy with x-ray optics, it is shown that this regime results in total
external reflection and air-guiding of light. In addition, the strong reduction
of the wavevector in the ITO below that of free space enables a new surface
plasmon polariton mode which can be excited without requiring a prism or
grating coupler. Ultrafast control of the surface plasmon polariton mode is
achieved with a modulation amplitude reaching 20%.


title:
Inverse Z-spectrum analysis for MT- and spillover-corrected and
  T1-compensated steady-state pulsed CEST-MRI - application to pH-weighted MRI
  of acute stroke

abstract:
  Endogenous chemical exchange saturation transfer (CEST) effects are always
diluted by competing effects such as direct water proton saturation (spillover)
and macromolecular magnetization transfer (MT). This leads to T2-and
MT-shine-through effects in the actual biochemical contrast of CEST. Therefore,
a simple evaluation algorithm which corrects the CEST signal was searched for.
By employing a recent eigenspace theory valid for spinlock and continuous wave
(cw) CEST we predict that the inverse Z-spectrum is beneficial to Z-spectrum
itself. Based on this we propose a new spillover- and MT-corrected
magnetization transfer ratio (MTRRex) yielding Rex, the exchange dependent
relaxation rate in the rotating frame. For verification, the amine proton
exchange of creatine in solutions with different agar concentration was studied
experimentally at clinical field strength of 3T. In contrast to the compared
standard evaluation for pulsed CEST experiments, MTRasym, our approach shows no
T2 or MT shine through effect. We demonstrate that spillover can be corrected
properly and also quantitative evaluation of pH and creatine concentration is
possible which proves MTRRex as quantitative CEST-MRI method. A spillover
correction is of special interest for clinical static field strengths and
protons resonating near the water peak. This is the case for -OH-CEST effects
like gagCEST or glucoCEST, but also amine exchange of creatine or glutamate
which require high B1. Although, only showed for amine exchange, we propose our
normalization to work generally for DIACEST, PARACEST in slow- and fast
exchange regime not just as a correction, but also for quantitative CEST-MRI.
Applied to acute stroke induced in rat brain, the corrected CEST signal shows
significantly higher contrast between stroke area and normal tissue as well as
less B1 dependency compared to conventional approaches.


title: Fractional Quantum Hall Physics in Topological Flat Bands

abstract:
  We present a pedagogical review of the physics of fractional Chern insulators
with a particular focus on the connection to the fractional quantum Hall
effect. While the latter conventionally arises in semiconductor
heterostructures at low temperatures and in high magnetic fields, interacting
Chern insulators at fractional band filling may host phases with the same
topological properties, but stabilized at the lattice scale, potentially
leading to high-temperature topological order. We discuss the construction of
topological flat band models, provide a survey of numerical results, and
establish the connection between the Chern band and the continuum Landau
problem. We then briefly summarize various aspects of Chern band physics that
have no natural continuum analogs, before turning to a discussion of possible
experimental realizations. We close with a survey of future directions and open
problems, as well as a discussion of extensions of these ideas to higher
dimensions and to other topological phases.


title:
Benchmark Tests for Markov Chain Monte Carlo Fitting of Exoplanet
  Eclipse Observations

abstract:
  Ground-based observations of exoplanet eclipses provide important clues to
the planets' atmospheric physics, yet systematics in light curve analyses are
not fully understood. It is unknown if measurements suggesting near-infrared
flux densities brighter than models predict are real, or artifacts of the
analysis processes. We created a large suite of model light curves, using both
synthetic and real noise, and tested the common process of light curve modeling
and parameter optimization with a Markov Chain Monte Carlo (MCMC) algorithm.
With synthetic white-noise models, we find that input eclipse signals are
generally recovered within 10% accuracy for eclipse depths greater than the
noise amplitude, and to smaller depths for higher sampling rates and longer
baselines. Red-noise models see greater discrepancies between input and
measured eclipse signals, often biased in one direction. Finally, we find that
in real data, systematic biases result even with a complex model to account for
trends, and significant false eclipse signals may appear in a non-Gaussian
distribution. To quantify the bias and validate an eclipse measurement, we
compare both the planet-hosting star and several of its neighbors to a
separately-chosen control sample of field stars. Re-examining the Rogers et al.
(2009) Ks-band measurement of CoRoT-1b finds an eclipse $3190^{+370}_{-440}$
ppm deep centered at $\phi_{me}$=$0.50418^{+0.00197}_{-0.00203}$. Finally, we
provide and recommend the use of selected datasets we generated as a benchmark
test for eclipse modeling and analysis routines, and propose criteria to verify
eclipse detections.


title:
Systematic Effects in Interferometric Observations of the CMB
  Polarization

abstract:
  The detection of the primordial $B$-mode spectrum of the polarized cosmic
microwave background (CMB) signal may provide a probe of inflation. However,
observation of such a faint signal requires excellent control of systematic
errors. Interferometry proves to be a promising approach for overcoming such a
challenge. In this paper we present a complete simulation pipeline of
interferometric observations of CMB polarization, including systematic errors.
We employ two different methods for obtaining the power spectra from mock data
produced by simulated observations: the maximum likelihood method and the
method of Gibbs sampling. We show that the results from both methods are
consistent with each other, as well as, within a factor of 6, with analytical
estimates. Several categories of systematic errors are considered: instrumental
errors, consisting of antenna gain and antenna coupling errors, and beam
errors, consisting of antenna pointing errors, beam cross-polarization and beam
shape (and size) errors. In order to recover the tensor-to-scalar ratio, $r$,
within a 10% tolerance level, which ensures the experiment is sensitive enough
to detect the $B$-signal at $r=0.01$ in the multipole range $28 < \ell < 384$,
we find that, for a QUBIC-like experiment, Gaussian-distributed systematic
errors must be controlled with precisions of $|g_{rms}| = 0.1$ for antenna
gain, $|\epsilon_{rms}| = 5 \times 10^{-4}$ for antenna coupling, $\delta_{rms}
\approx 0.7^\circ$ for pointing, $\zeta_{rms} \approx 0.7^\circ$ for beam
shape, and $\mu_{rms} = 5 \times 10^{-4}$ for beam cross-polarization.


title: Group Actions on Banach Spaces

abstract:
  We survey the recent developments concerning fixed point properties for group
actions on Banach spaces. In the setting of Hilbert spaces such fixed point
properties correspond to Kazhdan's property (T). Here we focus on the general,
non-Hilbert case, we discuss the methods, examples and several applications.


title:
Manipulation and coherence of ultra-cold atoms on a superconducting atom
  chip

abstract:
  The coherence of quantum systems is crucial to quantum information
processing. While it has been demonstrated that superconducting qubits can
process quantum information at microelectronics rates, it remains a challenge
to preserve the coherence and therefore the quantum character of the
information in these systems. An alternative is to share the tasks between
different quantum platforms, e.g. cold atoms storing the quantum information
processed by superconducting circuits. In our experiment, we characterize the
coherence of superposition states of 87Rb atoms magnetically trapped on a
superconducting atom-chip. We load atoms into a persistent-current trap
engineered in the vicinity of an off-resonance coplanar resonator, and observe
that the coherence of hyperfine ground states is preserved for several seconds.
We show that large ensembles of a million of thermal atoms below 350 nK
temperature and pure Bose-Einstein condensates with 3.5 x 10^5 atoms can be
prepared and manipulated at the superconducting interface. This opens the path
towards the rich dynamics of strong collective coupling regimes.


title:
The Next Generation Virgo Cluster Survey. IV. NGC 4216: A Bombarded
  Spiral in the Virgo Cluster

abstract:
  We present an investigation into the origins of a series of interlaced narrow
filamentary stellar structures, loops and plumes in the vicinity of the Virgo
Cluster, edge-on spiral galaxy, NGC 4216 that were previously identified by the
Blackbird Telescope. Using the deeper, higher-resolution and precisely
calibrated optical CFHT/MegaCam images obtained as part of the Next Generation
Virgo Cluster Survey (NGVS), we confirm the previously identified features and
identify a few additional structures. The NGVS data allowed us to make a
physical study of these low-surface brightness features and investigate their
origin. The likely progenitors of the structures were identified as either
already catalogued VCC dwarfs or newly discovered satellites caught in the act
of being destroyed. They have the same g-i color index and likely contain
similar stellar populations. The alignment of three dwarfs along an apparently
single stream is intriguing, and we cannot totally exclude that these are
second-generation dwarf galaxies being born inside the filament from the debris
of an original dwarf. The observed complex structures, including in particular
a stream apparently emanating from a satellite of a satellite, point to a high
rate of ongoing dwarf destruction/accretion in the region of the Virgo Cluster
where NGC 4216 is located. We discuss the age of the interactions and whether
they occurred in a group that is just falling into the cluster and shows signs
of so-called "pre-processing" before it gets affected by the cluster
environment, or in a group which already ventured towards the central regions
of Virgo Cluster.


title: Dynamics of Few Co-rotating Vortices in Bose-Einstein Condensates

abstract:
  We study the dynamics of small vortex clusters with few (2--4) co-rotating
vortices in Bose-Einstein condensates by means of experiments, numerical
computations, and theoretical analysis. All of these approaches corroborate the
counter-intuitive presence of a dynamical instability of symmetric vortex
configurations. The instability arises as a pitchfork bifurcation at
sufficiently large values of the angular momentum that induces the emergence
and stabilization of asymmetric rotating vortex configurations. The latter are
quantified in the theoretical model and observed in the experiments. The
dynamics is explored both for the integrable two-vortex system, where a
reduction of the phase space of the system provides valuable insight, as well
as for the non-integrable three- (or more) vortex case, which additionally
admits the possibility of chaotic trajectories.


title: An Introductory Study on Time Series Modeling and Forecasting

abstract:
  Time series modeling and forecasting has fundamental importance to various
practical domains. Thus a lot of active research works is going on in this
subject during several years. Many important models have been proposed in
literature for improving the accuracy and effectiveness of time series
forecasting. The aim of this dissertation work is to present a concise
description of some popular time series forecasting models used in practice,
with their salient features. In this thesis, we have described three important
classes of time series models, viz. the stochastic, neural networks and SVM
based models, together with their inherent forecasting strengths and
weaknesses. We have also discussed about the basic issues related to time
series modeling, such as stationarity, parsimony, overfitting, etc. Our
discussion about different time series models is supported by giving the
experimental forecast results, performed on six real time series datasets.
While fitting a model to a dataset, special care is taken to select the most
parsimonious one. To evaluate forecast accuracy as well as to compare among
different models fitted to a time series, we have used the five performance
measures, viz. MSE, MAD, RMSE, MAPE and Theil's U-statistics. For each of the
six datasets, we have shown the obtained forecast diagram which graphically
depicts the closeness between the original and forecasted observations. To have
authenticity as well as clarity in our discussion about time series modeling
and forecasting, we have taken the help of various published research works
from reputed journals and some standard books.


title:
Identification of slow molecular order parameters for Markov model
  construction

abstract:
  A goal in the kinetic characterization of a macromolecular system is the
description of its slow relaxation processes, involving (i) identification of
the structural changes involved in these processes, and (ii) estimation of the
rates or timescales at which these slow processes occur. Most of the approaches
to this task, including Markov models, Master-equation models, and kinetic
network models, start by discretizing the high-dimensional state space and then
characterize relaxation processes in terms of the eigenvectors and eigenvalues
of a discrete transition matrix. The practical success of such an approach
depends very much on the ability to finely discretize the slow order
parameters. How can this task be achieved in a high-dimensional configuration
space without relying on subjective guesses of the slow order parameters? In
this paper, we use the variational principle of conformation dynamics to derive
an optimal way of identifying the "slow subspace" of a large set of prior order
parameters - either generic internal coordinates (distances and dihedral
angles), or a user-defined set of parameters. It is shown that a method to
identify this slow subspace exists in statistics: the time-lagged independent
component analysis (TICA). Furthermore, optimal indicators-order parameters
indicating the progress of the slow transitions and thus may serve as reaction
coordinates-are readily identified. We demonstrate that the slow subspace is
well suited to construct accurate kinetic models of two sets of molecular
dynamics simulations, the 6-residue fluorescent peptide MR121-GSGSW and the
30-residue natively disordered peptide KID. The identified optimal indicators
reveal the structural changes associated with the slow processes of the
molecular system under analysis.


title:
PSO based Neural Networks vs. Traditional Statistical Models for
  Seasonal Time Series Forecasting

abstract:
  Seasonality is a distinctive characteristic which is often observed in many
practical time series. Artificial Neural Networks (ANNs) are a class of
promising models for efficiently recognizing and forecasting seasonal patterns.
In this paper, the Particle Swarm Optimization (PSO) approach is used to
enhance the forecasting strengths of feedforward ANN (FANN) as well as Elman
ANN (EANN) models for seasonal data. Three widely popular versions of the basic
PSO algorithm, viz. Trelea-I, Trelea-II and Clerc-Type1 are considered here.
The empirical analysis is conducted on three real-world seasonal time series.
Results clearly show that each version of the PSO algorithm achieves notably
better forecasting accuracies than the standard Backpropagation (BP) training
method for both FANN and EANN models. The neural network forecasting results
are also compared with those from the three traditional statistical models,
viz. Seasonal Autoregressive Integrated Moving Average (SARIMA), Holt-Winters
(HW) and Support Vector Machine (SVM). The comparison demonstrates that both
PSO and BP based neural networks outperform SARIMA, HW and SVM models for all
three time series datasets. The forecasting performances of ANNs are further
improved through combining the outputs from the three PSO based models.


title:
Hydrogen chloride in diffuse interstellar clouds along the line of sight
  to W31C (G10.6-0.4)

abstract:
  We report the detection of hydrogen chloride, HCl, in diffuse molecular
clouds on the line of sight towards the star-forming region W31C (G10.6-0.4).
The J = 1-0 lines of the two stable HCl isotopologues, H35Cl and H37Cl, are
observed using the 1b receiver of the Heterodyne Instrument for the
Far-Infrared (HIFI) aboard the Herschel Space Observatory. The HCl line is
detected in absorption, over a wide range of velocities associated with diffuse
clouds along the line of sight to W31C. The analysis of the absorption strength
yields a total HCl column density of few 10^13 cm^-2, implying that HCl
accounts for ~0.6 % of the total gasphase chlorine, which exceeds by a factor
of ~6 the theoretical model predictions. This result is comparable to those
obtained from the chemically-related species H2Cl+ and HCl+, for which large
column densities have also been reported on the same line of sight. The source
of discrepancy between models and observations is still unknown; however, the
detection of these Cl-bearing molecules, provides key constraints for the
chlorine chemistry in the diffuse gas.


title:
Arriving on time: estimating travel time distributions on large-scale
  road networks

abstract:
  Most optimal routing problems focus on minimizing travel time or distance
traveled. Oftentimes, a more useful objective is to maximize the probability of
on-time arrival, which requires statistical distributions of travel times,
rather than just mean values. We propose a method to estimate travel time
distributions on large-scale road networks, using probe vehicle data collected
from GPS. We present a framework that works with large input of data, and
scales linearly with the size of the network. Leveraging the planar topology of
the graph, the method computes efficiently the time correlations between
neighboring streets. First, raw probe vehicle traces are compressed into pairs
of travel times and number of stops for each traversed road segment using a
`stop-and-go' algorithm developed for this work. The compressed data is then
used as input for training a path travel time model, which couples a Markov
model along with a Gaussian Markov random field. Finally, scalable inference
algorithms are developed for obtaining path travel time distributions from the
composite MM-GMRF model. We illustrate the accuracy and scalability of our
model on a 505,000 road link network spanning the San Francisco Bay Area.


title: t tbar charge asymmetry, family and friends

abstract:
  We present the current status of the Tevatron charge asymmetry and its sister
asymmetry at the LHC. The relation between both is elucidated, using as
framework the collider-independent asymmetries they originate from. Other
related observables, such as the t tbar differential distribution and top
polarisation, are also discussed.


title: Discovery of Molecular Hydrogen in White Dwarf Atmospheres

abstract:
  With the Cosmic Origins Spectrograph onboard the Hubble Space Telescope, we
have detected molecular hydrogen in the atmospheres of three white dwarfs with
effective temperatures below 14,000 K, G29-38, GD 133 and GD 31. This discovery
provides new independent constraints on the stellar temperature and surface
gravity of white dwarfs.


title:
Galaxies in X-ray Groups. III. Satellite Color and Morphology
  Transformations

abstract:
  While the star formation rates and morphologies of galaxies have long been
known to correlate with their local environment, the process by which these
correlations are generated is not well understood. Galaxy groups are thought to
play an important role in shaping the physical properties of galaxies before
entering massive clusters at low redshift, and transformations of satellite
galaxies likely dominate the buildup of local environmental correlations. To
illuminate the physical processes that shape galaxy evolution in dense
environments, we study a sample of 116 X-ray selected galaxy groups at z=0.2-1
with halo masses of 10^13-10^14 M_sun and centroids determined with weak
lensing. We analyze morphologies based on HST imaging and colors determined
from 31 photometric bands for a stellar mass-limited population of 923
satellite galaxies and a comparison sample of 16644 field galaxies. Controlling
for variations in stellar mass across environments, we find significant trends
in the colors and morphologies of satellite galaxies with group-centric
distance and across cosmic time. Specifically at low stellar mass
(log(M_stellar/M_sun) = 9.8-10.3), the fraction of disk-dominated star-forming
galaxies declines from >50% among field galaxies to <20% among satellites near
the centers of groups. This decline is accompanied by a rise in quenched
galaxies with intermediate bulge+disk morphologies, and only a weak increase in
red bulge-dominated systems. These results show that both color and morphology
are influenced by a galaxy's location within a group halo. We suggest that
strangulation and disk fading alone are insufficient to explain the observed
morphological dependence on environment, and that galaxy mergers or close tidal
encounters must play a role in building up the population of quenched galaxies
with bulges seen in dense environments at low redshift.


title:
Cooperative non-equilibrium phase transition in a dilute Rydberg
  ensemble

abstract:
  We demonstrate a non-equilibrium phase transition in a dilute thermal atomic
gas. The phase transition, between states of low and high Rydberg occupancy, is
induced by resonant dipole-dipole interactions between Rydberg atoms. The gas
can be considered as dilute as the atoms are separated by distances much
greater than the wavelength of the optical transitions used to excite them. In
the frequency domain we observe a mean-field shift of the Rydberg state which
results in intrinsic optical bistability above a critical Rydberg number
density. In the time domain we observe critical slowing down where the recovery
time to system perturbations diverges with critical exponent
  $\tau=0.53 \pm 0.10$. The atomic emission spectrum of the phase with high
Rydberg occupancy provides evidence for a superradiant cascade.


title:
The evolution of HI and CIV quasar absorption line systems at 1.9 < z <
  3.2

abstract:
  We have investigated the distribution and evolution of ~3100 intergalactic HI
absorbers with HI column densities log N(HI) = [12.75, 17.0] at 1.9 < z < 3.2,
using 18 high resolution, high S/N quasar spectra obtained from the ESO
VLT/UVES archive. We used two sets of Voigt profile fitting analysis, one
including all the available high-order Lyman lines to obtain reliable HI column
densities of saturated lines, and another using only the Ly-alpha lines. There
is no significant difference between the results from the two fits. Combining
our results with literature data, the mean number density at 0 < z < 4 is not
well described by a single power law and strongly suggests that its evolution
slows down at z < 1.5 at the high and low column density ranges. We also
divided our entire HI absorbers at 1.9 < z < 3.2 into two samples, the
unenriched forest and the CIV-enriched forest, depending on whether HI lines
are associated with CIV at log N(CIV) > 12.2 within a given velocity range. The
entire HI column density distribution function (CDDF) can be described as the
combination of these two well-characterised populations which overlap at log
N(HI) ~ 15. At log N(HI) < 15, the unenriched forest dominates, showing a
similar power-law distribution to the entire forest. The CIV-enriched forest
dominates at log N(HI) > 15, with its distribution function proportional to
N(HI)^(-1.45). However, it starts to flatten out at lower N(HI), since the
enriched forest fraction decreases with decreasing N(HI). The deviation from
the power law at log N(HI) = [14, 17] shown in the CDDF for the entire HI
sample is a result of combining two different HI populations with a different
CDDF shape. The total HI mass density relative to the critical density is
Omega(HI) ~ 1.6 x 10^(-6) h^(-1), where the enriched forest accounts for ~40%
of Omega(HI).


title: Revisiting binary stars in population synthesis models

abstract:
  We report results of a population synthesis model that follows the evolution
of single and binary stars. In this model we include the 2HeWD merger channel,
suggested by Han et al. (2002), for the formation of EHB stars. The physical
parameters of the resulting EHB stars are derived from the BaSTI database, and
are thus realistic and observationally supported. The predictions of this model
are in good agreement with traditional population synthesis models, except when
the spectrum of the stellar population is dominated by binary stars or their
products, e.g., EHB stars in the UV of ETGs. We reproduce successfully the
observed CMD and SED of the metal rich open cluster NGC 6791. The stellar
population in this cluster may be archetypal of the stellar population in ETGs
that show the UVX phenomenon. Our models should be appropriate to study the UV
upturn in ETGs.


title:
Identified charged hadron production in Pb-Pb collisions at the LHC with
  the ALICE Experiment

abstract:
  Identified particle spectra represent a crucial tool to understand the
behavior of the matter created in high-energy heavy-ion collisions. The
transverse momentum p_T distributions of identified hadrons contain
informations about the transverse expansion of the system and constrain the
freezeout properties of the matter created. The ALICE experiment has good
particle identification performance over a broad p_T range. In this
contribution the results for identified pions, kaons and protons in heavy-ion
collisions at 2.76 TeV center-of-mass energy are presented. These results are
compared with other identified particle measurements obtained by previous
experiments, and discussed in terms of the thermal and hydrodynamic pictures.
The status of extensions of this analysis, with the study of identified
particles as a function of event-by-event flow in Pb-Pb collisions, is also
discussed.


title: A Partial EM Algorithm for Clustering White Breads

abstract:
  The design of new products for consumer markets has undergone a major
transformation over the last 50 years. Traditionally, inventors would create a
new product that they thought might address a perceived need of consumers. Such
products tended to be developed to meet the inventors own perception and not
necessarily that of consumers. The social consequence of a top-down approach to
product development has been a large failure rate in new product introduction.
By surveying potential customers, a refined target is created that guides
developers and reduces the failure rate. Today, however, the proliferation of
products and the emergence of consumer choice has resulted in the
identification of segments within the market. Understanding your target market
typically involves conducting a product category assessment, where 12 to 30
commercial products are tested with consumers to create a preference map. Every
consumer gets to test every product in a complete-block design; however, many
classes of products do not lend themselves to such approaches because only a
few samples can be evaluated before `fatigue' sets in. We consider an analysis
of incomplete balanced-incomplete-block data on 12 different types of white
bread. A latent Gaussian mixture model is used for this analysis, with a
partial expectation-maximization (PEM) algorithm developed for parameter
estimation. This PEM algorithm circumvents the need for a traditional E-step,
by performing a partial E-step that reduces the Kullback-Leibler divergence
between the conditional distribution of the missing data and the distribution
of the missing data given the observed data. The results of the white bread
analysis are discussed and some mathematical details are given in an appendix.


title: Stellar Superfluids

abstract:
  Neutron stars provide a fertile environment for exploring superfluidity under
extreme conditions. It is not surprising that Cooper pairing occurs in dense
matter since nucleon pairing is observed in nuclei as energy differences
between even-even and odd-even nuclei. Since superfluids and superconductors in
neutron stars profoundly affect neutrino emissivities and specific heats, their
presence can be observed in the thermal evolution of neutron stars. An
ever-growing number of cooling neutron stars, now amounting to 13 thermal
sources, and several additional objects from which upper limits to temperatures
can be ascertained, can now be used to discriminate among theoretical scenarios
and even to dramatically restrict properties of nucleon pairing at high
densities. In addition, observations of pulsars, including their spin-downs and
glitch histories, additionally support the conjecture that superfluidity and
superconductivity are ubiquitous within, and important to our understanding of,
neutron stars.

categories: astro-ph.HE cond-mat.supr-con hep-ph nucl-th


title:
Quantization of Special Symplectic Nilpotent Orbits and Normality of
  their Closures

abstract:
  We study the regular function ring $R(\mathcal{O})$ for all symplectic
nilpotent orbits $\mathcal{O}$ with even column sizes. We begin by recalling
the quantization model for all such orbits by Barbasch using unipotent
representations. With this model, we express the multiplicities of fundamental
representations appearing in $R(\mathcal{O})$ by a parabolically induced
module. Finally, we will use this formula to give a criterion on the normality
of the Zariski closure $\bar{\mathcal{O}}$ of $\mathcal{O}$.


title: Probing the mass assembly of massive nearby galaxies with deep imaging

abstract:
  According to a popular scenario supported by numerical models, the mass
assembly and growth of massive galaxies, in particular the Early-Type Galaxies
(ETGs), is, below a redshift of 1, mainly due to the accretion of multiple
gas--poor satellites. In order to get observational evidence of the role played
by minor dry mergers, we are obtaining extremely deep optical images of a
complete volume limited sample of nearby ETGs.
  These observations, done with the CFHT as part of the \AD, NGVS and MATLAS
projects, reach a stunning 28.5)29 mag.arcsec-2 surface brightness limit in the
g' band. They allow us to detect the relics of past collisions such as faint
stellar tidal tails as well as the very extended stellar halos which keep the
memory of the last episodes of galactic accretion.
  Images and preliminary results from this on-going survey are presented, in
particular a possible correlation between the fine structure index (which
parametrizes the amount of tidal perturbation) of the ETGs, their stellar mass,
effective radius and gas content.


title:
CoCo Bonds Valuation with Equity- and Credit-Calibrated First Passage
  Structural Models

abstract:
  After the beginning of the credit and liquidity crisis, financial
institutions have been considering creating a convertible-bond type contract
focusing on Capital. Under the terms of this contract, a bond is converted into
equity if the authorities deem the institution to be under-capitalized. This
paper discusses this Contingent Capital (or Coco) bond instrument and presents
a pricing methodology based on firm value models. The model is calibrated to
readily available market data. A stress test of model parameters is illustrated
to account for potential model risk. Finally, a brief overview of how the
instrument performs is presented.


title:
More Reliable Measurements of the Slip Length with the Atomic Force
  Microscope

abstract:
  Further improvements are made to the non-linear data analysis algorithm for
the atomic force microscope [P. Attard, arXiv:1212.3019v2 (2012)]. The
algorithm is required when there is curvature in the compliance region due to
photo-diode non-linearity. Results are obtained for the hydrodynamic drainage
force, for three surfaces: hydrophilic silica (symmetric, Si-Si), hydrophobic
dichlorodimethylsilane (symmetric, DCDMS-DCDMS), and hydrophobic
octadecyltrichlorosilane (asymmetric, Si-OTS). The drainage force was measured
in the viscous liquid di-n-octylphthalate. The slip-lengths are found to be 3nm
for Si, 2nm for DCDMS, and 2nm for OTS, with an uncertainty on the order of a
nanometer. These slip lengths are a factor of 4--15 times smaller than those
obtained from previous analysis of the same raw data [L. Zhu et al., Langmuir,
27, 6712 (2011). Ibid, 28, 7768 (2012)].

categories: cond-mat.soft physics.chem-ph physics.flu-dyn physics.ins-det


title:
The Vast Population of Wolf-Rayet and Red Supergiant Stars in M101: I.
  Motivation and First Results

abstract:
  M101 is an ideal target in which to test predictions of massive star birth
and evolution. The large abundance gradient across M101 (a factor of 20)
suggests that many more WR stars must be found in the inner parts of this
galaxy than in the outer regions. Many HII regions and massive star-forming
complexes have been identified in M101; they should be rich in WR stars, and
surrounded by RSG stars. Finally, the Wolf-Rayet stars in M101 may be abundant
enough for one to explode as a Type Ib or Ic supernova and/or GRB within a
generation. The clear identification of the progenitor of a Type Ib or Ic
supernova as a WR star would be a major confirmation of current stellar
evolution theory.
  Motivated by these considerations, we have used the Hubble Space Telescope to
carry out a deep, HeII optical narrowband imaging survey of the massive star
populations in the ScI spiral galaxy M101. Combined with archival broadband
images, we were able to image almost the entire galaxy with the unprecedented
depth and resolution that only HST affords.
  We describe the extent of the survey and our images, as well as our data
reduction procedures. A detailed study of a field east of the center of M101,
containing the giant star-forming region NGC 5462, demonstrates how we find
candidates, their properties and spatial distribution, and how we rule out most
contaminants. The spatial distributions of the WR and RSG stars near a giant
star-forming complex are strikingly different. WR stars dominate the complex
core, while RSG dominate the complex halo. Future papers in this series will
describe and catalog more than a thousand WR and RSG candidates that are
detectable in our images, as well as spectra of many of those candidates.


title: Constructive proof of the Carpenter's Theorem

abstract:
  We give a constructive proof of Carpenter's Theorem due to Kadison. Unlike
the original proof our approach also yields the real case of this theorem.


title: On Global Regularity of 2D Generalized Magnetohydrodynamic Equations

abstract:
  In this article we study the global regularity of 2D generalized
magnetohydrodynamic equations (2D GMHD), in which the dissipation terms are $-
\nu (- \triangle)^{\alpha} u$ and $- \kappa (-\triangle)^{\beta} b$. We show
that smooth solutions are global in the following three cases: $\alpha
\geqslant 1 / 2, \beta \geqslant 1$; $0 \leqslant \alpha < 1 / 2, 2 \alpha +
\beta > 2$; $\alpha \geqslant 2, \beta = 0$. We also show that in the inviscid
case $\nu = 0$, if $\beta > 1$, then smooth solutions are global as long as the
direction of the magnetic field remains smooth enough.


title:
A Matrix-Field Weighted Mean-Square-Error Model for MIMO Transceiver
  Designs

abstract:
  In this letter, we investigate an important and famous issue, namely weighted
mean-square-error (MSE) minimization transceiver designs. In our work, for
transceiver designs a novel weighted MSE model is proposed, which is defined as
a linear matrix function with respect to the traditional data detection MSE
matrix. The new model can be interpreted an extension of weighting operation
from vector field to matrix field. Based on the proposed weighting operation a
general transceiver design is proposed, which aims at minimizing an increasing
matrix-monotone function of the output of the previous linear matrix function.
The structure of the optimal solutions is also derived. Furthermore, two
important special cases of the matrix-monotone functions are discussed in
detail. It is also revealed that these two problems are exactly equivalent to
the transceiver designs of sum MSE minimization and capacity maximization for
dual-hop amplify-and-forward (AF) MIMO relaying systems, respectively. Finally,
it is concluded that the AF relaying is undoubtedly this kind of weighting
operation.


title:
Phonon Softening and Direct to Indirect Bandgap Crossover in Strained
  Single Layer MoSe2

abstract:
  Motivated by recent experimental observations of Tongay et al. [Tongay et
al., Nano Letters, 12(11), 5576 (2012)] we show how the electronic properties
and Raman characteristics of single layer MoSe2 are affected by elastic biaxial
strain. We found that with increasing strain: (1) the E' and E" Raman peaks
(E1g and E2g in bulk) exhibit significant red shifts (up to 30 cm-1), (2) the
position of the A1' peak remains at 180 cm-1 (A1g in bulk) and does not change
considerably with further strain, (3) the dispersion of low energy flexural
phonons crosses over from quadratic to linear and (4) the electronic band
structure undergoes a direct to indirect bandgap crossover under 3% biaxial
tensile strain. Thus the application of strain appears to be a promising
approach for a rapid and reversible tuning of the electronic, vibrational and
optical properties of single layer MoSe2 and similar MX2 dichalcogenides.


title: A Scalable Generative Graph Model with Community Structure

abstract:
  Network data is ubiquitous and growing, yet we lack realistic generative
network models that can be calibrated to match real-world data. The recently
proposed Block Two-Level Erdss-Renyi (BTER) model can be tuned to capture two
fundamental properties: degree distribution and clustering coefficients. The
latter is particularly important for reproducing graphs with community
structure, such as social networks. In this paper, we compare BTER to other
scalable models and show that it gives a better fit to real data. We provide a
scalable implementation that requires only O(d_max) storage where d_max is the
maximum number of neighbors for a single node. The generator is trivially
parallelizable, and we show results for a Hadoop MapReduce implementation for a
modeling a real-world web graph with over 4.6 billion edges. We propose that
the BTER model can be used as a graph generator for benchmarking purposes and
provide idealized degree distributions and clustering coefficient profiles that
can be tuned for user specifications.


title:
Spherical Collapse of a Unified Dark Fluid with Constant Adiabatic Sound
  Speed

abstract:
  In this paper, we test the spherical collapse of a unified dark fluid (UDF)
which has constant adiabatic sound speed. By choosing the different values of
model parameters $B_s$ and $\alpha$, we show the nonlinear collapse for UDF and
baryons which are considered for their formation of the large scale structure
of our Universe. The analyzed results show that larger values of $\alpha$ and
$B_s$ make the structure formation faster and earlier.


title: All-optical control of a solid-state spin using coherent dark states

abstract:
  The study of individual quantum systems in solids, for use as quantum bits
(qubits) and probes of decoherence, requires protocols for their
initialization, unitary manipulation, and readout. In many solid-state quantum
systems, these operations rely on disparate techniques that can vary widely
depending on the particular qubit structure. One such qubit, the
nitrogen-vacancy (NV) center spin in diamond, can be initialized and read out
through its special spin selective intersystem crossing, while microwave
electron spin resonance (ESR) techniques provide unitary spin rotations.
Instead, we demonstrate an alternative, fully optical approach to these control
protocols in an NV center that does not rely on its intersystem crossing. By
tuning an NV center to an excited-state spin anticrossing at cryogenic
temperatures, we use coherent population trapping and stimulated Raman
techniques to realize initialization, readout, and unitary manipulation of a
single spin. Each of these techniques can be directly performed along any
arbitrarily-chosen quantum basis, removing the need for extra control steps to
map the spin to and from a preferred basis. Combining these protocols, we
perform measurements of the NV center's spin coherence, a demonstration of this
full optical control. Consisting solely of optical pulses, these techniques
enable control within a smaller footprint and within photonic networks.
Likewise, this approach obviates the need for both ESR manipulation and spin
addressability through the intersystem crossing. This method could therefore be
applied to a wide range of potential solid-state qubits, including those which
currently lack a means to be addressed.

categories: quant-ph cond-mat.mes-hall cond-mat.mtrl-sci physics.atom-ph


title: The STAR W Program at RHIC

abstract:
  The production of $W$ bosons in polarized $p+p$ collisions at RHIC provides
an excellent tool to probe the proton's sea quark distributions. At leading
order $W^{-(+)}$ bosons are produced in $\bar{u}+d\,(\bar{d}+u)$ collisions,
and parity-violating single-spin asymmetries measured in longitudinally
polarized $p+p$ collisions give access to the flavor-separated light quark and
antiquark helicity distributions. In this proceedings we report preliminary
results for the single-spin asymmetry, $A_L$ from data collected in 2012 by the
STAR experiment at RHIC with an integrated luminosity of 72 pb$^{-1}$ at
$\sqrt{s}=510$ GeV and an average beam polarization of 56%.


title: The Auslander-Gorenstein property for Z-algebras

abstract:
  We provide a framework for part of the homological theory of Z-algebras and
their generalizations, directed towards analogues of the Auslander-Gorenstein
condition and the associated double Ext spectral sequence that are useful for
enveloping algebras of Lie algebras and related rings. As an application, we
prove the equidimensionality of the characteristic variety of an irreducible
representation of the Z-algebra, and for related representations over quantum
symplectic resolutions. In the special case of Cherednik algebras of type A,
this answers a question raised by the authors.


title:
Why some heaps support constant-amortized-time decrease-key operations,
  and others do not

abstract:
  A lower bound is presented which shows that a class of heap algorithms in the
pointer model with only heap pointers must spend Omega(log log n / log log log
n) amortized time on the decrease-key operation (given O(log n) amortized-time
extract-min). Intuitively, this bound shows the key to having O(1)-time
decrease-key is the ability to sort O(log n) items in O(log n) time; Fibonacci
heaps [M.L. Fredman and R. E. Tarjan. J. ACM 34(3):596-615 (1987)] do this
through the use of bucket sort. Our lower bound also holds no matter how much
data is augmented; this is in contrast to the lower bound of Fredman [J. ACM
46(4):473-501 (1999)] who showed a tradeoff between the number of augmented
bits and the amortized cost of decrease-key. A new heap data structure, the
sort heap, is presented. This heap is a simplification of the heap of Elmasry
[SODA 2009: 471-476] and shares with it a O(log log n) amortized-time
decrease-key, but with a straightforward implementation such that our lower
bound holds. Thus a natural model is presented for a pointer-based heap such
that the amortized runtime of a self-adjusting structure and amortized lower
asymptotic bounds for decrease-key differ by but a O(log log log n) factor.


title: A Laurent series proof of the Habsieger-Kadell $q$-Morris Identity

abstract:
  We give a Laurent series proof of the Habsieger-Kadell $q$-Morris identity,
which is a common generalization of the $q$-Morris identity and the Aomoto
constant term identity. The proof allows us to extend the theorem for some
additional parameter cases.


title: Aspects of Warped AdS$_3$/CFT$_2$ Correspondence

abstract:
  In this paper we apply the thermodynamics method to investigate the
holographic pictures for the BTZ black hole, the spacelike and the null warped
black holes in three-dimensional topologically massive gravity (TMG) and new
massive gravity (NMG). Even though there are higher derivative terms in these
theories, the thermodynamics method is still effective. It gives consistent
results with the ones obtained by using asymptotical symmetry group (ASG)
analysis. In doing the ASG analysis we develop a brute-force realization of the
Barnich-Brandt-Compere formalism with Mathematica code, which also allows us to
calculate the masses and the angular momenta of the black holes. In particular,
we propose the warped AdS$_3$/CFT$_2$ correspondence in the new massive
gravity, which states that quantum gravity in the warped spacetime could
holographically dual to a two-dimensional CFT with
$c_R=c_L=\f{24}{Gm\b^2\sr{2(21-4\b^2)}}$.


title:
The Mid-Infrared and Near-Ultraviolet Excess Emissions of Quiescent
  Galaxies on the Red Sequence

abstract:
  We study the mid-infrared (IR) and near-ultraviolet (UV) excess emissions of
spectroscopically selected quiescent galaxies on the optical red sequence. We
use the Wide-field Infrared Survey Explorer ({\it WISE}) mid-IR and Galaxy
Evolution Explorer ({\it GALEX}) near-UV data for a spectroscopic sample of
galaxies in the Sloan Digital Sky Survey Data Release 7 to study the possible
connection between quiescent red-sequence galaxies with and without
mid-IR/near-UV excess. Among 648 12 $\mu$m detected quiescent red-sequence
galaxies without H$\alpha$ emission, 26% and 55% show near-UV and mid-IR excess
emissions, respectively. When we consider only bright ($M_{r}$ $<$ $-$21.5)
galaxies with early-type morphology, the fraction of galaxies with recent star
formation is still 39%. The quiescent red-sequence galaxies with mid-IR and
near-UV excess emissions are optically fainter and have slightly smaller
$D_{n}$4000 than those without mid-IR and near-UV excess emissions. We also
find that mid-IR weighted mean stellar ages of quiescent red-sequence galaxies
with mid-IR excess are larger than those with near-UV excess, and smaller than
those without mid-IR and near-UV excess. The environmental dependence of the
fraction of quiescent red-sequence galaxies with mid-IR and near-UV excess
seems strong even though the trends of quiescent red-sequence galaxies with
near-UV excess differ from those with mid-IR excess. These results indicate
that the recent star formation traced by near-UV ($\lesssim 1$ Gyr) and mid-IR
($\lesssim 2$ Gyr) excess is not negligible among nearby, quiescent, red,
early-type galaxies. We suggest a possible evolutionary scenario of quiescent
red-sequence galaxies from quiescent red-sequence galaxies with near-UV excess
to those with mid-IR excess to those without near-UV and mid-IR excess.


title: Chiral Symmetry Restoration from a Boundary

abstract:
  The boundary of a manifold can alter the phase of a theory in the bulk. We
explore the possibility of a boundary-induced phase transition for the chiral
symmetry of QCD. In particular, we investigate the consequences of imposing
homogeneous Dirichlet boundary conditions on the quark fields. Such boundary
conditions are sometimes employed in lattice gauge theory computations, for
example, when including external electromagnetic fields, or when computing
quark propagators with a reduced temporal extent. Homogeneous Dirichlet
boundary conditions force the chiral condensate to vanish at the boundary, and
thereby obstruct the spontaneous breaking of chiral symmetry in the bulk. We
show the restoration of chiral symmetry due to a boundary is a non-perturbative
phenomenon depending upon the mechanism of spontaneous symmetry breaking, and
utilize the sigma model to exemplify the issues. Within this model, we find
that chiral symmetry is completely restored if the length of the compact
direction is less than 2.0 fm. For lengths greater than about 4 fm, an
approximately uniform chiral condensate forms centered about the midpoint of
the compact direction. While the volume-averaged condensate approaches the
infinite volume value as the compact direction becomes very long, the
finite-size corrections are shown to be power law rather than exponential.


title:
On the Construction of Radio Environment Maps for Cognitive Radio
  Networks

abstract:
  The Radio Environment Map (REM) provides an effective approach to Dynamic
Spectrum Access (DSA) in Cognitive Radio Networks (CRNs). Previous results on
REM construction show that there exists a tradeoff between the number of
measurements (sensors) and REM accuracy. In this paper, we analyze this
tradeoff and determine that the REM error is a decreasing and convex function
of the number of measurements (sensors). The concept of geographic entropy is
introduced to quantify this relationship. And the influence of sensor
deployment on REM accuracy is examined using information theory techniques. The
results obtained in this paper are applicable not only for the REM, but also
for wireless sensor network deployment.


title:
On the large deviation rate function for the empirical measures of
  reversible jump Markov processes

abstract:
  The large deviations principle for the empirical measure for both continuous
and discrete time Markov processes is well known. Various expressions are
available for the rate function, but these expressions are usually as the
solution to a variational problem, and in this sense not explicit. An
interesting class of continuous time, reversible processes was identified in
the original work of Donsker and Varadhan for which an explicit expression is
possible. While this class includes many (reversible) processes of interest, it
excludes the case of continuous time pure jump processes, such as a reversible
finite state Markov chain. In this paper, we study the large deviations
principle for the empirical measure of pure jump Markov processes and provide
an explicit formula of the rate function under reversibility.


title: Model on pulsed GeV radiation from magnetars

abstract:
  We discuss a possible scenario for radiation mechanism of pulsed GeV
gamma-rays from magnetars. The magnetars have shown frequent X-ray bursts,
which would be triggered by crust fractures and could release the energy of
order of ~10^{41-42}erg. If the location of the crust cracking of the magnetic
field is close to the magnetic pole, part of the released energy may excite the
Alfevn wave that can propagate into outer magnetosphere. The oscillation of the
magnetic field induces the available potential drop ~10^{15}Volts, which can
accelerate the electrons and/or positrons to the Lorentz factor ~10^{7} in the
outer magnetosphere. The curvature radiation process at outer magnetosphere can
produce GeV gamma-rays. If the radiation process is occurred above r~5x 10^7cm
from the stellar surface, the emitted GeV gamma-rays can escape from the
pair-creation process with the X-rays and/or the magnetic field. The expected
luminosity of the GeV emissions is order of L_{\gamma}< 10^{35} erg/s, and the
radiation process will last for a temporal scale of years. The expected pulse
profiles have a broad shape with sometimes sharp peaks. We apply the model to
AXP 1E~2259+586.


title:
Collimation and scattering of the active galactic nucleus emission in
  the Sombrero galaxy

abstract:
  We present an analysis of a data cube of the central region of M104, the
Sombrero galaxy, obtained with the GMOS-IFU of the Gemini-South telescope, and
report the discovery of collimation and scattering of the active galactic
nucleus (AGN) emission in the circumnuclear region of this galaxy. Analysis
with PCA Tomography and spectral synthesis revealed the existence of
collimation and scattering of the AGN featureless continuum and also of a broad
component of the H{\alpha} emission line. The collimation and scattering of
this broad H{\alpha} component was also revealed by fitting the [NII]
{\lambda}{\lambda}6548,6583 and H{\alpha} emission lines as a sum of Gaussian
functions. The spectral synthesis, together with a V-I image obtained with the
Hubble Space Telescope, showed the existence of circumnuclear dust, which may
cause the light scattering. We also identify a dusty feature that may be
interpreted as a torus/disk structure. The existence of two opposite regions
with featureless continuum (P.A. = -18{\deg} +/- 13{\deg} and P.A. = 162{\deg}
+/- 13{\deg}) along a direction perpendicular to the torus/disk (P.A. =
72{\deg} +/- 14{\deg}) suggests that this structure is approximately edge-on
and collimates the AGN emission. The edge-on torus/disk also hides the
broad-line region. The proposed scenario is compatible with the Unified Model
and explains why only a weak broad component of the H{\alpha} emission line is
visible and also why many previous studies detected no broad H\alpha. The
technique used here proved to be an efficient method not only for detecting
scattered light but also for testing the Unified Model in low luminosity AGNs.


title: Anomalous Local Criticality in Heavy Fermion Metals from Holography

abstract:
  We propose a holographic theory to explain numbers of anomalous critical
phenomena observed in certain heavy-fermion metals, e.g.
$\mathrm{CeCu_{5.9}Au_{0.1}}$ and $\mathrm{YbRh_{2}(Si_{0.95}Ge_{0.05}})_{2}$,
which are incompatible with any conventional spin-density-wave quantum critical
point theory. We show that the non-Gaussian nature of the fixed point from
holography plays an essential role in the physics of these materials near a
quantum critical point, which is not in the same universality class of the
spin-density-wave type fixed point. The critical spin fluctuations at the
non-Gaussian fixed point are strongly anisotropic, localized in spatial
directions and critical in temporal direction with critical exponent 2/3 in
frequency over temperature dependence at low temperature. The local critical
exponent tends to unity which leads to a constant spin relaxation rate in the
quantum critical regime at high temperature. The stability of the fixed point
is also discussed.


title:
Statistical Inference on Transformation Models: a Self-induced Smoothing
  Approach

abstract:
  This paper deals with a general class of transformation models that contains
many important semiparametric regression models as special cases. It develops a
self-induced smoothing for the maximum rank correlation estimator, resulting in
simultaneous point and variance estimation. The self-induced smoothing does not
require bandwidth selection, yet provides the right amount of smoothness so
that the estimator is asymptotically normal with mean zero (unbiased) and
variance-covariance matrix consistently estimated by the usual sandwich-type
estimator. An iterative algorithm is given for the variance estimation and
shown to numerically converge to a consistent limiting variance estimator. The
approach is applied to a data set involving survival times of primary biliary
cirrhosis patients. Simulations results are reported, showing that the new
method performs well under a variety of scenarios.


title: Rotational circulant graphs

abstract:
  A Frobenius group is a transitive permutation group which is not regular but
only the identity element can fix two points. Such a group can be expressed as
the semi-direct product $G = K \rtimes H$ of a nilpotent normal subgroup $K$
and another group $H$ fixing a point. A first-kind $G$-Frobenius graph is a
connected Cayley graph on $K$ with connection set an $H$-orbit $a^H$ on $K$
that generates $K$, where $H$ has an even order or $a$ is an involution. It is
known that the first-kind Frobenius graphs admit attractive routing and
gossiping algorithms. A complete rotation in a Cayley graph on a group $G$ with
connection set $S$ is an automorphism of $G$ fixing $S$ setwise and permuting
the elements of $S$ cyclically. It is known that if the fixed-point set of such
a complete rotation is an independent set and not a vertex-cut, then the
gossiping time of the Cayley graph (under a certain model) attains the smallest
possible value. In this paper we classify all first-kind Frobenius circulant
graphs that admit complete rotations, and describe a means to construct them.
This result can be stated as a necessary and sufficient condition for a
first-kind Frobenius circulant to be 2-cell embeddable on a closed orientable
surface as a balanced regular Cayley map. We construct a family of
non-Frobenius circulants admitting complete rotations such that the
corresponding fixed-point sets are independent and not vertex-cuts. We also
give an infinite family of counterexamples to the conjecture that the
fixed-point set of every complete rotation of a Cayley graph is not a
vertex-cut.


title:
The Unified Segment Tree and its Application to the Rectangle
  Intersection Problem

abstract:
  In this paper we introduce a variation on the multidimensional segment tree,
formed by unifying different interpretations of the dimensionalities of the
data structure. We give some new definitions to previously well-defined
concepts that arise naturally in this variation, and we show some properties
concerning the relationships between the nodes, and the regions those nodes
represent. We think these properties will enable the data to be utilized in new
situations, beyond those previously studied. As an example, we show that the
data structure can be used to solve the Rectangle Intersection Problem in a
more straightforward and natural way than had be done in the past.


title:
Dynamics of double-well Bose-Einstein Condensates subject to external
  Gaussian white noise

abstract:
  Dynamical properties of the Bose-Einstein condensate in double-well potential
subject to Gaussian white noise are investigated by numerically solving the
time-dependent Gross-Pitaevskii equation. The Gaussian white noise is used to
describe influence of the random environmental disturbance on the double-well
condensate. Dynamical evolutions from three different initial states, the
Josephson oscillation state, the running phase and $\pi$-mode macroscopic
quantum self-trapping states are considered. It is shown that the system is
rather robust with respect to the weak noise whose strength is small and change
rate is high. If the evolution time is sufficiently long, the weak noise will
finally drive the system to evolve from high energy states to low energy
states, but in a manner rather different from the energy-dissipation effect. In
presence of strong noise with either large strength or slow change rate, the
double-well condensate may exhibit very irregular dynamical behaviors.


title: HCMU metrics with cusp singularities and conical singularities

abstract:
  An HCMU metric is a conformal metric which has a finite number of
singularities on a compact Riemann surface and satisfies the equation of the
extremal K\"{a}hler metric. In this paper, we give a necessary and sufficient
condition for the existence of a kind of HCMU metrics which has both cusp
singularities and conical singularities.


title: Quantum Spin Hall Effect in a Three-orbital Tight-binding Hamiltonian

abstract:
  We consider the quantum spin hall state in a three orbital model due to
certain loop current order induced by spin-dependent interactions. This type of
order is motivated by the loop current model which is proposed to describe the
pseudogap phase of cuprates. It is shown that this model has nontrivial Chern
parity by directly counting the zeros of the Pfaffian of time reversal
operator. By connecting to the second order Chern number, we explicitly show
the singularities of wave-functions and how they depend on gauge choices. In
this case, it is shown that the Berry phase can be mapped to Nonabelian
instanton.


title:
Topologically protected mid-gap states induced by impurity in
  one-dimensional superlattices

abstract:
  Based on the discovery of the nontrivial topology of one-dimensional
superlattices, we show that midgap states will emerge in such systems induced
by a single on-site impurity. Besides the trivial bound state located at the
impurity site, these midgap states are localized at the adjacent sides of the
impurity, carrying the information of the topology and behaving like the effect
of the open boundary conditions in the limit of a large attractive or repulsive
impurity potential. Using this feature, the impurity can be used to detect the
topology of the superlattice system and to realize the adiabatic pumping
between the opposite sides of the impurity in cold-atom experiments or in
photonic crystals.


title:
Cosmic Censorship: Formation of a Shielding Horizon Around a Fragile
  Horizon

abstract:
  The weak cosmic censorship conjecture asserts that spacetime singularities
that arise in gravitational collapse are always hidden inside of black holes,
invisible to distant observers. This conjecture, put forward by Penrose more
than four decades ago, is widely believed to be one of the basic principles of
nature. However, a complete proof of this hypothesis is still lacking and the
validity of the conjecture has therefore remained one of the most important
open questions in general relativity. In this study we analyze a gedanken
experiment which is designed to challenge cosmic censorship by trying to
overcharge a Reissner-Nordstr\"om black hole: a charged shell is lowered {\it
adiabatically} into the charged black hole. The mass-energy delivered to the
black hole can be red-shifted by letting the dropping point of the shell
approach the black-hole horizon. On the other hand, the electric charge of the
shell is not red-shifted by the gravitational field of the black hole. It
therefore seems, at first sight, that the charged shell is not hindered from
entering the black hole, overcharging it and removing its horizon. However, in
the present study we prove that the exposure of a naked singularity to distant
observers is actually excluded due to the formation of a new (and {\it larger})
horizon around the original black hole. Moreover, we shall prove that this new
horizon is already formed {\it before} the charged shell crosses the original
black-hole horizon. This result, which seems to have been previously
overlooked, guarantees the validity of the weak cosmic censorship conjecture in
this type of gedanken experiments.


title: On randomized confidence intervals for the binomial probability

abstract:
  Suppose that X_1,X_2,...,X_n are independent and identically Bernoulli(theta)
distributed. Also suppose that our aim is to find an exact confidence interval
for theta that is the intersection of a 1-\alpha/2 upper confidence interval
and a 1-\alpha/2 lower confidence interval. The Clopper-Pearson interval is the
standard such confidence interval for theta, which is widely used in practice.
We consider the randomized confidence interval of Stevens, 1950 and present
some extensions, including pseudorandomized confidence intervals. We also
consider the "data-randomized" confidence interval of Korn, 1987 and point out
some additional attractive features of this interval. We also contribute to the
discussion about the practical use of such confidence intervals.


title: Optimal rate algebraic list decoding using narrow ray class fields

abstract:
  We use class field theory, specifically Drinfeld modules of rank 1, to
construct a family of asymptotically good algebraic-geometric (AG) codes over
fixed alphabets. Over a field of size $\ell^2$, these codes are within
$2/(\sqrt{\ell}-1)$ of the Singleton bound. The functions fields underlying
these codes are subfields with a cyclic Galois group of the narrow ray class
field of certain function fields. The resulting codes are "folded" using a
generator of the Galois group. This generalizes earlier work by the first
author on folded AG codes based on cyclotomic function fields. Using the
Chebotarev density theorem, we argue the abundance of inert places of large
degree in our cyclic extension, and use this to devise a linear-algebraic
algorithm to list decode these folded codes up to an error fraction approaching
$1-R$ where $R$ is the rate. The list decoding can be performed in polynomial
time given polynomial amount of pre-processed information about the function
field.
  Our construction yields algebraic codes over constant-sized alphabets that
can be list decoded up to the Singleton bound --- specifically, for any desired
rate $R \in (0,1)$ and constant $\eps > 0$, we get codes over an alphabet size
$(1/\eps)^{O(1/\eps^2)}$ that can be list decoded up to error fraction
$1-R-\eps$ confining close-by messages to a subspace with $N^{O(1/\eps^2)}$
elements. Previous results for list decoding up to error-fraction $1-R-\eps$
over constant-sized alphabets were either based on concatenation or involved
taking a carefully sampled subcode of algebraic-geometric codes. In contrast,
our result shows that these folded algebraic-geometric codes {\em themselves}
have the claimed list decoding property.


title: Uniform electron gases. I. Electrons on a ring

abstract:
  We introduce a new paradigm for one-dimensional uniform electron gases
(UEGs). In this model, $n$ electrons are confined to a ring and interact via a
bare Coulomb operator. We use Rayleigh-Schr\"odinger perturbation theory to
show that, in the high-density regime, the ground-state reduced (i.e. per
electron) energy can be expanded as $\eps(r_s,n) = \eps_0(n) r_s^{-2} +
\eps_1(n) r_s^{-1} + \eps_2(n) +\eps_3(n) r_s + \ldots$, where $r_s$ is the
Seitz radius. We use strong-coupling perturbation theory and show that, in the
low-density regime, the reduced energy can be expanded as $\eps(r_s,n) =
\eta_0(n) r_s^{-1} + \eta_1(n) r_s^{-3/2} + \eta_2(n) r_s^{-2} + \ldots$. We
report explicit expressions for $\eps_0(n)$, $\eps_1(n)$, $\eps_2(n)$,
$\eps_3(n)$, $\eta_0(n)$ and $\eta_1(n)$ and derive the thermodynamic
(large-$n$) limits of each of these. Finally, we perform numerical studies of
UEGs with $n = 2, 3, \ldots, 10$, using Hylleraas-type and quantum Monte Carlo
methods, and combine these with the perturbative results to obtain a picture of
the behavior of the new model over the full range of $n$ and $r_s$ values.


title: Integrated Polarization Properties of 3C48, 3C138, 3C147, and 3C286

abstract:
  We present the integrated polarization properties of the four compact radio
sources 3C48, 3C138, 3C147 and 3C286, from 1 to 50 GHz, over a 30-year time
frame spanning 1982 to 2012. These four sources are commonly used as flux
density and polarization calibrators for cm-wave interferometers. Using the
polarized emission of Mars, we have determined that the true position angle of
the linearly polarized emission of 3C286 rises from 33 degrees at 8 GHz to 36
degrees at 45 GHz. There is no evidence for a change in the position angle over
time. Using these values, the position angles of the intergrated polarized
emission from the other sources are determined as a function of frequency and
time. The fractional polarization of 3C286 is found to be slowly rising, at all
frequencies, at a rate of ~0.015%/year. The fractional polarizations of 3C48,
3C138, and 3C147 are all slowly variable, with the variations clearly
correlated with changes in the total flux densities of these sources.


title:
Long-Range Order of the Three-Sublattice Structure in the S = 1
  Heisenberg Antiferromagnet on a Spatially Anisotropic Triangular Lattice

abstract:
  We study the S=1 Heisenberg antiferromagnet on a spatially anisotropic
triangular lattice by the numerical diagonalization method. We examine the
stability of the long-range order of a three-sublattice structure observed in
the isotropic system between the isotropic case and the case of isolated
one-dimensional chains. It is found that the long-range-ordered ground state
with this structure exists in the range of 0.7 \simle J_2/J_1 \le 1, where J_1
is the interaction amplitude along the chains and J_2 is the amplitude of other
interactions.


title: New Restriction Estimates for the 3-d Paraboloid over Finite Fields

abstract:
  We improve the range of exponents for the restriction problem for the 3-d
paraboloid over finite fields. The key new ingredient is a variant of the
Bourgain-Katz-Tao finite field incidence theorem derived from sum-product
estimates. In prime order fields, we give an explicit relationship between the
exponent in this incidence theorem and restriction estimates for the
paraboloid.


title: On Farber's invariants for simple $2q$-knots

abstract:
  Let $K$ be a simple $2q$-knot with exterior $X$. We show directly how the
Farber quintuple $(A,\Pi,\alpha,\ell,\psi)$ determines the homotopy type of $X$
if the torsion subgroup of $A=\pi_q(X)$ has odd order. We comment briefly on
the possible role of the EHP sequence in recovering the boundary inclusion from
the duality pairings $\ell $ and $\psi$. Finally we reformulate the Farber
quintuple as an hermitian self-duality of an object in an additive category
with involution.


title:
Large Scale Real-time Ridesharing with Service Guarantee on Road
  Networks

abstract:
  The mean occupancy rates of personal vehicle trips in the United States is
only 1.6 persons per vehicle mile. Urban traffic gridlock is a familiar scene.
Ridesharing has the potential to solve many environmental, congestion, and
energy problems. In this paper, we introduce the problem of large scale
real-time ridesharing with service guarantee on road networks. Servers and trip
requests are dynamically matched while waiting time and service time
constraints of trips are satisfied. We first propose two basic algorithms: a
branch-and-bound algorithm and an integer programing algorithm. However, these
algorithm structures do not adapt well to the dynamic nature of the ridesharing
problem. Thus, we then propose a kinetic tree algorithm capable of better
scheduling dynamic requests and adjusting routes on-the-fly. We perform
experiments on a large real taxi dataset from Shanghai. The results show that
the kinetic tree algorithm is faster than other algorithms in response time.