title: Improved mass measurement using the boundary of many-body phase space

abstract:
  We show that mass measurements for new particles appearing in decay chains
can be improved by determining the boundary of the available phase space in its
full dimensionality rather than by using one-dimensional kinematic features for
each stage of the cascade decay. This is demonstrated for the case of one
particle decaying to three visible and one invisible particles in a two-stage
cascade, but our methods also apply to a more general set of decay topologies.
We show that not only mass differences, but also the overall scale of masses
can be determined with high precision without having to rely on cross section
information. The improvement arises from the properties of the higher
dimensional phase space itself, independent of the matrix element for the
decay, and it is not weakened by the presence of intermediate on-shell
particles in the cascade. Our results are particularly significant for the case
of low signal statistics, a distinct possibility for new physics searches in
the near future.


title:
Lepton flavor-violating transitions in effective field theory and
  gluonic operators

abstract:
  Lepton flavor-violating processes offer interesting possibilities to probe
new physics at multi-TeV scale. We discuss those in the framework of effective
field theory, emphasizing the role of gluonic operators. Those operators are
obtained by integrating out heavy quarks that are kinematically inaccessible at
the scale where low-energy experiments take place and make those experiments
sensitive to the couplings of lepton flavor changing neutral currents to heavy
quarks. We discuss constraints on the Wilson coefficients of those operators
from the muon conversion $\mu^- + (A,Z) \to e^- + (A,Z)$ and from lepton
flavor-violating tau decays with one or two hadrons in the final state, e.g.
$\tau \to \ell \ \eta^{(\prime)}$ and $\tau \to \ell \ \pi^+\pi^-$ with $\ell =
\mu, e$. To illustrate the results we discuss explicit examples of constraining
parameters of leptoquark models.


title: Semidefinite Relaxations for Best Rank-1 Tensor Approximations

abstract:
  This paper studies the problem of finding best rank-1 approximations for both
symmetric and nonsymmetric tensors. For symmetric tensors, this is equivalent
to optimizing homogeneous polynomials over unit spheres; for nonsymmetric
tensors, this is equivalent to optimizing multi-quadratic forms over
multi-spheres. We propose semidefinite relaxations, based on sum of squares
representations, to solve these polynomial optimization problems. Their
properties and structures are studied. In applications, the resulting
semidefinite programs are often large scale. The recent Newton-CG augmented
Lagrangian method by Zhao, Sun and Toh is suitable for solving these
semidefinite relaxations. Extensive numerical experiments are presented to show
that this approach is practical in getting best rank-1 approximations.


title:
Attainment of the multiple quantum Chernoff bound for certain ensembles
  of mixed states

abstract:
  We consider the problem of detecting the true quantum state among r possible
ones, based on measurements performed on n of copies of a finite dimensional
quantum system. It is known that the exponent for the rate of decrease of the
averaged error probability cannot exceed the multiple quantum Chernoff bound
(MQCB) defined as the worst case (smallest) quantum Chernoff distance between
any possible pair of the r states. This error exponent is attainable for r pure
states, but for the general case of mixed states only attainability up to a
factor 1/3 is known. Here we show that the MQCB is attainable for mixed states
if there is a pair which is closer in quantum Chernoff distance than 1/6 times
the distance between all other pairs.


title: Turbulence comes in bursts in stably stratified flows

abstract:
  There is a clear distinction between simple laminar and complex turbulent
fluids. But in some cases, as for the nocturnal planetary boundary layer, a
stable and well-ordered flow can develop intense and sporadic bursts of
turbulent activity which disappear slowly in time. This phenomenon is
ill-understood and poorly modeled; and yet, it is central to our understanding
of weather and climate dynamics. We present here a simple model which shows
that in stably stratified turbulence, the stronger bursts can occur when the
flow is expected to be more stable. The bursts are generated by a rapid
non-linear amplification of energy stored in waves, and are associated with
energetic interchanges between vertical velocity and temperature (or density)
fluctuations. Direct numerical simulations on grids of 2048^3 points confirm
this somewhat paradoxical result of measurably stronger events for more stable
flows, displayed not only in the temperature and vertical velocity derivatives,
but also in the amplitude of the fields themselves.


title: Natural scaling for dark energy

abstract:
  We propose a dark energy density based on the Gauss-Bonnet 4-dimensional
invariant and its modification. This model avoids the necessity of introducing
the black hole limit to define the holographic density, since it can be
considered as a non-saturated regime. This allows to describe the dark energy
with an equation of state and Hubble parameter behaving in a way that can be
adjusted very well to recent observations. The model presents quintom behavior
without any future finite-time singularities.


title:
Classification and construction of closed-form kernels for signal
  representation on the 2-sphere

abstract:
  This paper considers the construction of Reproducing Kernel Hilbert Spaces
(RKHS) on the sphere as an alternative to the conventional Hilbert space using
the inner product that yields the L^2(S^2) function space of finite energy
signals. In comparison with wavelet representations, which have
multi-resolution properties on L^2(S^2), the representations that arise from
the RKHS approach, which uses different inner products, have an overall
smoothness constraint, which may offer advantages and simplifications in
certain contexts. The key contribution of this paper is to construct classes of
closed-form kernels, such as one based on the von Mises-Fisher distribution,
which permits efficient inner product computation using kernel evaluations.
Three classes of RKHS are defined: isotropic kernels and non-isotropic kernels
both with spherical harmonic eigenfunctions, and general anisotropic kernels.


title: The closed-string 3-loop amplitude and S-duality

abstract:
  The low-energy limit of the four-point 3-loop amplitude (including its
overall coefficient) is computed in both type IIA and IIB superstring theories
using the pure spinor formalism. The result is shown to agree with the
prediction of the coefficient for the type IIB $D^6 R^4$ interaction made by
Green and Vanhove based on S-duality considerations.


title: Elliptic flow from thermal photons with magnetic field in holography

abstract:
  We compute the elliptic flow $v_2$ of thermal photons in a strongly coupled
plasma with constant magnetic field via gauge/gravity duality. The D3/D7
embedding is applied to generate the contributions from massive quarks. By
considering the cases in 2+1 flavor SYM analogous to the photon production in
QGP, we obtain the thermal-photon $v_2$, which is qualitatively consistent with
the direct-photon $v_2$ measured in RHIC at intermediate energy. However, due
to the simplified setup, the thermal-photon $v_2$ in our model should be
regarded as the upper bound for the $v_2$ generated by solely magnetic field in
the strongly coupled scenario.


title: Magnification Bias in Gravitational Arc Statistics

abstract:
  The statistics of gravitational arcs in galaxy clusters is a powerful probe
of cluster structure and may provide complementary cosmological constraints.
Despite recent progresses, discrepancies still remain among modelling and
observations of arc abundance, specially regarding the redshift distribution of
strong lensing clusters. Besides, fast "semi-analytic" methods still have to
incorporate the success obtained with simulations. In this paper we discuss the
contribution of the magnification in gravitational arc statistics. Although
lensing conserves surface brightness, the magnification increases the
signal-to-noise ratio of the arcs, enhancing their detectability. We present an
approach to include this and other observational effects in semi-analytic
calculations for arc statistics. The cross section for arc formation ({\sigma})
is computed through a semi-analytic method based on the ratio of the
eigenvalues of the magnification tensor. Using this approach we obtained the
scaling of {\sigma} with respect to the magnification, and other parameters,
allowing for a fast computation of the cross section. We apply this method to
evaluate the expected number of arcs per cluster using an elliptical
Navarro--Frenk--White matter distribution. Our results show that the
magnification has a strong effect on the arc abundance, enhancing the fraction
of arcs, moving the peak of the arc fraction to higher redshifts, and softening
its decrease at high redshifts. We argue that the effect of magnification
should be included in arc statistics modelling and that it could help to
reconcile arcs statistics predictions with the observational data.


title: Stick-breaking PG(\alpha,\zeta)-Generalized Gamma Processes

abstract:
  This work centers around results related to Proposition 21 of Pitman and
Yor's (1997) paper on the two parameter Poisson Dirichlet distribution indexed
by (\alpha,\theta) for 0<\alpha<1, also \alpha=0, and \theta>-\alpha, denoted
PD(\alpha,\theta). We develop explicit stick-breaking representations for a
class that contains the PD(\alpha,\theta) for the range \theta=0, and \theta>0,
we call PG(\alpha,\zeta). We also construct a larger class, EPG(\alpha,\zeta),
containing the entire range. These classes are indexed by \alpha, and an
arbitrary non-negative random variable \zeta. The bulk of this work focuses on
investigating various properties of this larger class, EPG(\alpha,\zeta), which
lead to connections to other work in the literature. In particular, we develop
completely explicit stick-breaking representations for this entire class via
size biased sampling as described in Perman, Pitman and Yor (1992). This
represents the first case outside of the PD(\alpha,\theta) where one obtains
explicit results for the entire range of \alpha, the EPG are within the larger
class of mass partitions generated by conditioning on the total mass of an
\alpha-stable subordinator. Furthermore Markov chains are derived which
establish links between Markov chains derived from
stick-breaking(insertion/deletion), as described in Perman, Pitman and Yor and
Markov chains derived from successive usage of dual coagulation fragmentation
operators described in Bertoin and Goldschmidt and Dong, Goldschmidt and
Martin. Which have connections to certain types of fragmentation trees and
coalescents appearing in the recent literature. Our results are also suggestive
of new models and tools, for applications in Bayesian Nonparametrics/Machine
Learning, where PD(\alpha,\theta) bridges are often referred to as Pitman-Yor
processes.


title: Mathematical quantum Yang-Mills theory revisited

abstract:
  A mathematically rigorous relativistic quantum Yang-Mills theory with an
arbitrary semisimple compact gauge Lie group is set up in the Hamiltonian
canonical formalism. The theory is non-perturbative, without cut-offs, and
agrees with the causality and stability principles. This paper presents a fully
revised, simplified, and corrected version of the corresponding material in the
previous papers DYNIN[11] and [12]. The principal result is established anew:
due to the quartic self-interaction term in the Yang-Mills Lagrangian along
with the semisimplicity of the gauge group, the quantum Yang-Mills energy
spectrum has a positive mass gap. Furthermore, the quantum Yang-Mills
Hamiltonian has a countable orthogonal eigenbasis in a Fock space, so that the
quantum Yang-Mills spectrum is point and countable. In addition a fine
structure of the spectrum is elucidated.
  KEYS: Millennium Yang-Mills problem; Finite propagation speed; Sobolev
inequalities; Nuclear vector spaces; Infinite-dimensional holomorphy;
Friedrichs operator extensions; Variational spectral principle; Symbols and
spectral theory of pseudo-differential operators.


title: Observer and Particle Transformations and Newton's Laws

abstract:
  A frequently confused point in studies of symmetry violation is the
distinction between observer and particle transformations. In this work, we
consider a model in which a coefficient in the Standard-Model Extension leads
to violations of rotation invariance in Newton's second law. The model
highlights the distinction between observer and particle transformations.


title: The RR Lyrae variables and Horizontal Branch of NGC6656 (M22)

abstract:
  The first calibrated broadband UBVI time-series photometry is presented for
the RR Lyrae variable stars in NGC6656 (M22), with observations spanning a
range of twenty-two years. We have also redetermined the variability types and
periods for the RR Lyrae stars identified previously by photographic
observations, revising the number of fundamental-mode RR Lyrae variables (RR0)
to 10 and the number of first-overtone variables (RR1) to 16. The mean periods
of the RR0 and RR1 variables are <P>_{RR0}=0.66 \pm 0.02 d and <P>_{RR1}=0.33
\pm 0.01 d, respectively, supporting an Oosterhoff II classification for the
cluster. The number ratio of RR1- to all RR-type variables is N_1/N_{RR}=0.61,
also consistent with an Oosterhoff II designation. Both the RR Lyrae stars'
minimum light colors and the blue edge of the RR Lyrae instability strip
suggest E(B-V)=0.36 \pm 0.02 mag toward M22. Regarding the HB morphology of
M22, we find (B-R)/(B+V+R)=+0.97 \pm 0.1 and at least one "gap" located in an
unusual part of the blue HB, in the middle of the so-called hot HB stars.


title:
A hot Jupiter transiting a mid-K dwarf found in the pre-OmegaCam Transit
  Survey

abstract:
  We describe the pre-OmegaTranS project, a deep survey for transiting
extra-solar planets in the Carina region of the Galactic Disk. In 2006-2008 we
observed a single dense stellar field with a very high cadence of ~2min using
the ESO Wide Field Imager at the La Silla Observatory. Using the Astronomical
Wide-field System for Europe and the Munich Difference Imaging Analysis
pipeline, a module that has been developed for this project, we created the
light curves of 16000 stars with more than 4000 data points which we searched
for periodic transit signals using a box-fitting least-squares detection
algorithm. All light curves are publicly available. In the course of the
pre-OmegaTranS project we identified two planet candidates - POTS-1b and
POTS-C2b - which we present in this work. With extensive follow-up observations
we were able to confirm one of them, POTS-1b, a hot Jupiter transiting a mid-K
dwarf. The planet has a mass of 2.31+-0.77M_Jup and a radius of 0.94+-0.04R_Jup
and a period of P=3.16d. The host star POTS-1 has a radius of 0.59+-0.02R_Sun
and a mass of 0.70+-0.05M_Sun. Due to its low apparent brightness of I=16.1mag
the follow-up and confirmation of POTS-1b was particularly challenging and
costly.


title:
Dust Properties of Local Dust-Obscured Galaxies with the Submillimeter
  Array

abstract:
  We report Submillimeter Array (SMA) observations of the 880 \mu m dust
continuum emission for four dust-obscured galaxies (DOGs) in the local
universe. Two DOGs are clearly detected with S_\nu(880 \mu m)=10-13 mJy and
S/N>5, but the other two are not detected with 3{\sigma} upper limits of
S_\nu(880 \mu m)=5-9 mJy. Including an additional two local DOGs with
submillimeter data from the literature, we determine the dust masses and
temperatures for six local DOGs. The infrared luminosities and dust masses for
these DOGs are in the range 1.2-4.9x10^{11} (L_sun) and 4-14x10^{7} (M_sun),
respectively. The dust temperatures derived from a two-component modified
blackbody function are 23-26 K and 60-124 K for the cold and warm dust
components, respectively. Comparison of local DOGs with other infrared luminous
galaxies with submillimeter detections shows that the dust temperatures and
masses do not differ significantly among these objects. Thus, as argued
previously, local DOGs are not a distinctive population among dusty galaxies,
but simply represent the high-end tail of the dust obscuration distribution.


title:
Properties of M31. III: Candidate Beat Cepheids from PS1 PAndromeda Data
  and Their Implication on Metallicity Gradient

abstract:
  We present a sample of M31 beat Cepheids from the Pan-STARRS 1 PAndromeda
campaign. By analyzing three years of PAndromeda data, we identify seventeen
beat Cepheids, spreading from a galactocentric distance of 10 to 16 kpc. Since
the relation between fundamental mode period and the ratio of fundamental to
the first overtone period puts a tight constraint on metallicity we are able to
derive the metallicity at the position of the beat Cepheids using the relations
from the model of Buchler (2008). Our metallicity estimates show subsolar
values within 15 kpc, similar to the metallicities from HII regions (Zurita &
Bresolin 2012). We then use the metallicity estimates to calculate the
metallicity gradient of the M31 disk, which we find to be closer to the
metallicity gradient derived from planetary nebulae (Kwitter et al. 2012) than
the metallicity gradient from HII regions (Zurita & Bresolin 2012).


title:
On the influence of physical galaxy properties on Lyman-alpha escape in
  star-forming galaxies

abstract:
  [abridged] Among the different observational techniques used to select
high-redshift galaxies, the hydrogen recombination line Lyman-alpha (Lya) is of
particular interest as it gives access to the measurement of cosmological
quantities such as the star formation rate of distant galaxy populations.
However, the interpretation of this line and the calibration of such
observables is still subject to serious uncertainties. Therefore, it important
to understand under what conditions the Lya line can be used as a reliable star
formation diagnostic tool. We use a sample of 24 Lya emitters at z ~ 0.3 with
an optical spectroscopic follow-up to calculate the Lya escape fraction and its
dependency upon different physical properties. We also examine the reliability
of Lya as a star formation rate indicator. We combine these observations with a
compilation of Lya emitters selected at z = 0 - 0.3 to assemble a larger
sample. The Lya escape fraction depends clearly on the dust extinction
following the relation fesc(Lya) = C(Lya) x 10^(-0.4 E(B-V) k(Lya)), but with a
shallower slope than previously reported, with k(Lya) ~ 6.67 and C(Lya) = 0.22.
However, the correlation does not follow the expected curve for a simple dust
attenuation. We explore the various mechanisms than lead to fesc(Lya) values
above the continuum extinction curve, i.e. to an enhancement of the Lya output.
We also observe that the strength of Lya and the escape fraction appear
unrelated to the galaxy metallicity. Regarding the reliability of Lya as a star
formation rate (SFR) indicator, we show that the deviation of SFR(Lya) from the
true SFR (as traced by the UV continuum) is a function of the observed SFR(UV),
which can be seen as the decrease of fesc(Lya) with increasing UV luminosity.
Moreover, we observe a redshift-dependence of this relationship revealing the
underlying evolution of fesc(Lya) with redshift.


title:
The Lyman alpha Reference Sample: II. HST imaging results, integrated
  properties and trends

abstract:
  We report upon new results regarding the Lya output of galaxies, derived from
the Lyman alpha Reference Sample (LARS), focusing on Hubble Space Telescope
imaging. For 14 galaxies we present intensity images in Lya, Halpha, and UV,
and maps of Halpha/Hbeta, Lya equivalent width (EW), and Lya/Halpha. We present
Lya and UV light profiles and show they are well-fitted by S\'ersic profiles,
but Lya profiles show indices systematically lower than those of the UV (n
approx 1-2 instead of >~4). This reveals a general lack of the central
concentration in Lya that is ubiquitous in the UV. Photometric growth curves
increase more slowly for Lya than the FUV, showing that small apertures may
underestimate the EW. For most galaxies, however, flux and EW curves flatten by
radii ~10 kpc, suggesting that if placed at high-z, only a few of our galaxies
would suffer from large flux losses. We compute global properties of the sample
in large apertures, and show total luminosities to be independent of all other
quantities. Normalized Lya throughput, however, shows significant correlations:
escape is found to be higher in galaxies of lower star formation rate, dust
content, mass, and several quantities that suggest harder ionizing continuum
and lower metallicity. Eight galaxies could be selected as high-z Lya emitters,
based upon their luminosity and EW. We discuss the results in the context of
high-z Lya and UV samples. A few galaxies have EWs above 50 AA, and one shows
f_escLya of 80%; such objects have not previously been reported at low-z.


title: Fractionally charged impurity states of a fractional quantum Hall system

abstract:
  The single-particle spectral function for an incompressible fractional
quantum Hall state in the presence of a scalar short-ranged attractive impurity
potential is calculated via exact diagonalization within the spherical
geometry. In contrast to the noninteracting case, where only a single bound
state below the lowest Landau level forms, electron-electron interactions
strongly renormalize the impurity potential, effectively giving it a finite
range, which can support many quasi-bound states (long-lived resonances).
Averaging the spectral weights of the quasi-bound states and extrapolating to
the thermodynamic limit, for filling factor $\nu=1/3$ we find evidence
consistent with localized fractionally charged $e/3$ quasiparticles. For
$\nu=2/5$, the results are slightly more ambiguous, due to finite size effects
and possible bunching of Laughlin-quasiparticles.


title:
Warm Ice Giant GJ 3470b. I. A Flat Transmission Spectrum Indicates a
  Hazy, Low-methane, and/or Metal-rich Atmosphere

abstract:
  We report our spectroscopic investigation of the transiting ice giant GJ
3470b's atmospheric transmission, and the first results of extrasolar planet
observations from the new Keck/MOSFIRE spectrograph. We measure a planet/star
radius ratio of Rp/Rs = 0.0789 +/- 0.0020 in a bandpass from 2.09-2.36 micron
and in six narrower bands across this wavelength range. When combined with
existing broadband photometry, these measurements rule out cloud-free
atmospheres in chemical equilibrium assuming either solar abundances (5.4 sigma
confidence) or a moderate level of metal enrichment (50x solar abundances, 3.8
sigma), confirming previous results that such models are not representative for
cool, low-mass, externally irradiated extrasolar planets. Current measurements
are consistent with a flat transmission spectrum, which suggests that the
atmosphere is explained by high-altitude clouds and haze, disequilibrium
chemistry, unexpected abundance patterns, or the atmosphere is extremely
metal-rich (>200x solar). Because GJ 3470b's low bulk density sets an upper
limit on the planet's atmospheric enrichment of <300x solar, the atmospheric
mean molecular weight must be <9. Thus, if the atmosphere is cloud-free its
spectral features should be detectable with future observations. Transit
observations at shorter wavelengths will provide the best opportunity to
discriminate between plausible scenarios. We obtained optical spectroscopy with
the GMOS spectrograph, but these observations exhibit large systematic
uncertainties owing to thin, persistent cirrus conditions. Finally, we also
provide the first detailed look at the steps necessary for well-calibrated
MOSFIRE observations, and provide advice for future observations with this
instrument.


title:
Fast and Slow Rotators in the Densest Environments: a SWIFT IFS study of
  the Coma Cluster

abstract:
  We present integral-field spectroscopy of 27 galaxies in the Coma cluster
observed with the Oxford SWIFT spectrograph, exploring the kinematic
morphology-density relationship in a cluster environment richer and denser than
any in the ATLAS3D survey. Our new data enables comparison of the kinematic
morphology relation in three very different clusters (Virgo, Coma and Abell
1689) as well as to the field/group environment. The Coma sample was selected
to match the parent luminosity and ellipticity distributions of the early-type
population within a radius 15' (0.43 Mpc) of the cluster centre, and is limited
to r' = 16 mag (equivalent to M_K = -21.5 mag), sampling one third of that
population. From analysis of the lambda-ellipticity diagram, we find 15+-6% of
early-type galaxies are slow rotators; this is identical to the fraction found
in the field and the average fraction in the Virgo cluster, based on the
ATLAS3D data. It is also identical to the average fraction found recently in
Abell 1689 by D'Eugenio et al.. Thus it appears that the average slow rotator
fraction of early type galaxies remains remarkably constant across many
different environments, spanning five orders of magnitude in galaxy number
density. However, within each cluster the slow rotators are generally found in
regions of higher projected density, possibly as a result of mass segregation
by dynamical friction. These results provide firm constraints on the mechanisms
that produce early-type galaxies: they must maintain a fixed ratio between the
number of fast rotators and slow rotators while also allowing the total
early-type fraction to increase in clusters relative to the field. A complete
survey of Coma, sampling hundreds rather than tens of galaxies, could probe a
more representative volume of Coma and provide significantly stronger
constraints, particularly on how the slow rotator fraction varies at larger
radii.


title: Introduction to extragalactic sources of very high-energy photons

abstract:
  The launch of the Fermi gamma-ray space telescope and the imaging air
Cerenkov telescopes H.E.S.S., MAGIC, and VERITAS have substantially transformed
our knowledge of gamma-ray sources in the last decade. The extragalactic
gamma-ray sky is teeming with blazars, which are active galactic nuclei whose
jet is directed at us. Additionally, there are radio galaxies, starburst and
spiral galaxies, and gamma-ray bursts, albeit with smaller numbers. Galaxy
clusters have not yet been observed in gamma rays. Here, I will introduce the
different gamma-ray emission processes and review what they may tell us about
these objects and the underlying acceleration mechanisms. Beyond the study of
these fascinating objects, TeV gamma rays from blazars probe the integrated
star formation history of the universe. Studies of TeV blazar spectra may
provide us with insights into intergalactic magnetic fields or alternatively,
may lead us to infer the existence of a novel mechanism that heats the
intergalactic medium at late times (for redshifts z<3) and impacts the
Lyman-alpha forest and late-time structure formation. The TeV gamma-ray
emission may also allow us to probe fundamental physics such as the structure
of space time.


title:
Gravity duals of N = 2 superconformal field theories with no
  electrostatic description

abstract:
  We construct the first eleven-dimensional supergravity solutions, which are
regular, have no smearing and possess only SO(2,4) x SO(3) x U(1)_R isometry.
They are dual to four-dimensional field theories with N = 2 superconformal
symmetry. We utilise the Toda frame of self-dual four-dimensional Euclidean
metrics with SU(2) rotational symmetry. They are obtained by transforming the
Atiyah--Hitchin instanton under SL(2,R) and are expressed in terms of theta
functions. The absence of any extra U(1) symmetry, even asymptotically, renders
inapplicable the electrostatic description of our solution.


title: Time-Series BVI Photometry for the Globular Cluster NGC 6981 (M72)

abstract:
  We present new BVI photometry of the globular cluster NGC 6981 (M72), based
mostly on ground-based CCD archive images. We present a new color-magnitude
diagram (CMD) that reaches almost four magnitudes below the turn-off level. We
performed new derivations of metallicity and morphological parameters of the
evolved sequences, in good agreement with previous authors, obtaining a value
of [Fe/H] ~ -1.50 in the new UVES scale. We also identify the cluster's blue
straggler population. Comparing the radial distribution of these stars with the
red giant branch population, we find that the blue stragglers are more
centrally concentrated, as found in previous studies of blue stragglers in
globular clusters. Taking advantage of the large field of view covered by our
study, we analyzed the surface density profile of the cluster, finding
extratidal main sequence stars out to r ~ 14.1 arcmin or about twice the tidal
radius. We speculate that this may be due to tidal disruption in the course of
M72's orbit, in which case tidal tails associated with the cluster may exist.
We also take a fresh look at the variable stars in the cluster, recovering all
previous known variables, including three SX Phoenicis stars, and adding three
previously unknown RR Lyrae (1 c-type and 2 ab-type) to the total census.
Finally, comparing our CMD with unpublished data for M3 (NGC 5272), a cluster
with similar metallicity and horizontal branch morphology, we found that both
objects are essentially coeval.


title:
The SLUGGS Survey: Wide Field Imaging of the Globular Cluster System of
  NGC 4278

abstract:
  We use multi-pointing HST ACS and wide field Subaru Suprime-Cam imaging to
study the globular cluster system of the L* elliptical galaxy NGC 4278. We have
also obtained a handful of new globular cluster spectra with Keck/DEIMOS. We
determine the globular cluster surface density profile and use it to calculate
the total number of globular clusters, finding the system to be slightly more
populous than average for galaxies of its luminosity. We find clear evidence
for bimodality in the globular cluster colour distribution and for a
colour-magnitude relation in the blue subpopulation (a 'blue tilt'). We also
find negative radial colour gradients in both colour subpopulations of equal
strength which are similar in strength to those reported in other galaxies. The
sizes of NGC 4278's globular clusters decrease with redder colours and increase
with galactocentric radius. The ratio of the sizes of blue to red globular
clusters is independent of galactocentric radius demonstrating that internal
effects are responsible for the size difference with colour.


title: Canonical structure of Tetrad Bimetric Gravity

abstract:
  We perform the complete canonical analysis of the tetrad formulation of
bimetric gravity and confirm that it is ghost-free describing the seven degrees
of freedom of a massless and a massive gravitons. In particular, we find
explicit expressions for secondary constraints, one of which is responsible for
removing the ghost, whereas the other ensures the equivalence with the metric
formulation. Both of them have a remarkably simple form and, being combined
with conditions on Lagrange multipliers, can be written in a covariant way.


title: Black holes with surrounding matter in scalar-tensor theories

abstract:
  We uncover two mechanisms that can render Kerr black holes unstable in
scalar-tensor gravity, both associated to the presence of matter in the
vicinity of the black hole and the fact that this introduces an effective mass
for the scalar. Our results highlight the importance of understanding the
structure of spacetime in realistic, astrophysical black holes in scalar-tensor
theories.


title:
Resolving the Cosmic Far-Infrared Background at 450 and 850 Microns with
  SCUBA-2

abstract:
  We use the SCUBA-2 submillimeter camera mounted on the JCMT to obtain
extremely deep number counts at 450 and 850um. We combine data on two cluster
lensing fields, A1689 and A370, and three blank fields, CDF-N, CDF-S, and
COSMOS, to measure the counts over a wide flux range at each wavelength. We use
statistical fits to broken power law representations to determine the number
counts. This allows us to probe to the deepest possible level in the data. At
both wavelengths our results agree well with the literature in the flux range
over which they have been measured, with the exception of the 850um counts in
CDF-S, where we do not observe the counts deficit found by previous single-dish
observations. At 450um, we detect significant counts down to ~1mJy, an
unprecedented depth at this wavelength. By integrating the number counts above
this flux limit, we measure 113.9^{+49.7}_{-28.4} Jydeg^{-2} of the 450um
extragalactic background light (EBL). The majority of this contribution is from
sources with S_450um between 1-10mJy, and these sources are likely to be the
ones that are analogous to the local luminous infrared galaxies (LIRGs). At
850um, we measure 37.3^{+21.1}_{-12.9} Jydeg^{-2} of the EBL. Because of the
large systematic uncertainties on the COBE measurements, the percentage of the
EBL we resolve could range from 48%-153% (44%-178%) at 450 (850)um. Based on
high-resolution SMA observations of around half of the 4sigma 850um sample in
CDF-N, we find that 12.5^{+12.1}_{-6.8}% of the sources are blends of multiple
fainter sources. This is a low multiple fraction, and we find no significant
difference between our original SCUBA-2 850um counts and the multiplicity
corrected counts.


title:
Weighing Galaxy Clusters with Gas. II. On the Origin of Hydrostatic Mass
  Bias in LambdaCDM Galaxy Clusters

abstract:
  The use of galaxy clusters as cosmological probes hinges on our ability to
measure their masses accurately and with high precision. Hydrostatic mass is
one of the most common methods for estimating the masses of individual galaxy
clusters, which suffer from biases due to departures from hydrostatic
equilibrium. Using a large, mass-limited sample of massive galaxy clusters from
a high-resolution hydrodynamical cosmological simulation, in this work we show
that in addition to turbulent and bulk gas velocities, acceleration of gas
introduces biases in the hydrostatic mass estimate of galaxy clusters. In
unrelaxed clusters, the acceleration bias is comparable to the bias due to
non-thermal pressure associated with merger-induced turbulent and bulk gas
motions. In relaxed clusters, the mean mass bias due to acceleration is small
(<3%), but the scatter in the mass bias can be reduced by accounting for gas
acceleration. Additionally, this acceleration bias is greater in the outskirts
of higher redshift clusters where mergers are more frequent and clusters are
accreting more rapidly. Since gas acceleration cannot be observed directly, it
introduces an irreducible bias for hydrostatic mass estimates. This
acceleration bias places limits on how well we can recover cluster masses from
future X-ray and microwave observations. We discuss implications for cluster
mass estimates based on X-ray, Sunyaev-Zeldovich effect, and gravitational
lensing observations and their impact on cluster cosmology.


title:
Star Clusters in M31. V. Evidence for Self-Enrichment in Old M31
  Clusters from Integrated Spectroscopy

abstract:
  In the past decade, the notion that globular clusters (GCs) are composed of
coeval stars with homogeneous initial chemical compositions has been challenged
by growing evidence that they host an intricate stellar population mix, likely
indicative of a complex history of star formation and chemical enrichment.
Several models have been proposed to explain the existence of multiple stellar
populations in GCs, but no single model provides a fully satisfactory match to
existing data. Correlations between chemistry and global parameters such as
cluster mass or luminosity are fundamental clues to the physics of GC
formation. In this Letter, we present an analysis of the mean abundances of Fe,
Mg, C, N, and Ca for 72 old GCs from the Andromeda galaxy. We show for the
first time that there is a correlation between the masses of GCs and the mean
stellar abundances of nitrogen, spanning almost two decades in mass. This
result sheds new light on the formation of GCs, providing important constraints
on their internal chemical evolution and mass loss history.


title: Conformal great circle flows on the three-sphere

abstract:
  We consider a closed orientable Riemannian 3-manifold $(M,g)$ and a vector
field $X$ with unit norm whose integral curves are geodesics of $g$. Any such
vector field determines naturally a 2-plane bundle contained in the kernel of
the contact form of the geodesic flow of $g$. We study when this 2-plane bundle
remains invariant under two natural almost complex structures. We also provide
a geometric condition that ensures that $X$ is the Reeb vector field of the
1-form $\lambda$ obtained by contracting $g$ with $X$. We apply these results
to the case of great circle flows on the 3-sphere with two objectives in mind:
one is to recover the result in \cite{GG} that a volume preserving great circle
flow must be Hopf and the other is to characterize in a similar fashion great
circle flows that are conformal relative to the almost complex structure in the
kernel of $\lambda$ given by rotation by $\pi/2$ according to the orientation
of $M$.


title: Heisenberg-Kitaev model on hyperhoneycomb lattice

abstract:
  Motivated by recent experiments on $\beta-$Li$_2$IrO$_3$, we study the phase
diagram of the Heisenberg-Kitaev model on a three dimensional lattice of
tri-coordinated Ir$^{4+}$, dubbed the hyperhoneycomb lattice by Takagi et. al.
The lattice geometry of this material, along with Ir$^{4+}$ ions carrying
$J_{\rm eff}=1/2$ moments, suggests that the Heisenberg-Kitaev model may
effectively capture the low energy spin-physics of the system in the
strong-coupling limit. Using a combination of semiclassical analysis, exact
solution and slave-fermion mean field theory, we find, in addition to the
spin-liquid, four different magnetically ordered phases depending on the
parameter regime. All four magnetic phases--the N\'{e}el, the polarized
ferromagnet, the skew-stripy and the skew-zig-zag, have collinear spin
ordering. The three dimensional Z$_2$ spin liquid, which extends over an
extended parameter regime around the exactly solvable Kitaev point, has a
gapless Majorana mode with a deformed Fermi-circle (co-dimensions, $d_c=2$). We
discuss the effect of the magnetic field and finite temperature on different
phases that may be relevant for future experiments.


title:
Large Scale Anomalies in the Microwave Background: Causation and
  Correlation

abstract:
  Most treatments of large scale anomalies in the microwave sky are a
posteriori, with unquantified look-elsewhere effects. We contrast these with
physical models of specific inhomogeneities in the early universe which then
generate apparent anomalies. Physical models predict correlations between
candidate anomalies, as well as the corresponding signals in polarization and
large scale structure, reducing the impact of cosmic variance. We compute the
apparent spatial curvature associated with large-scale inhomogeneities and show
that it is typically small, allowing for a self-consistent analysis. Focussing
on a single large plane wave inhomogeneity, we show this can contribute to
low-l mode alignment and odd-even asymmetry in the power spectra and the best
fit inhomogeneity accounts for a significant part of the claimed odd-even
asymmetry. We argue that this approach can be generalized to provide a more
quantitative assessment of potential large scale anomalies in the universe.


title:
Mini-batch Stochastic Approximation Methods for Nonconvex Stochastic
  Composite Optimization

abstract:
  This paper considers a class of constrained stochastic composite optimization
problems whose objective function is given by the summation of a differentiable
(possibly nonconvex) component, together with a certain non-differentiable (but
convex) component. In order to solve these problems, we propose a randomized
stochastic projected gradient (RSPG) algorithm, in which proper mini-batch of
samples are taken at each iteration depending on the total budget of stochastic
samples allowed. The RSPG algorithm also employs a general distance function to
allow taking advantage of the geometry of the feasible region. Complexity of
this algorithm is established in a unified setting, which shows nearly optimal
complexity of the algorithm for convex stochastic programming. A
post-optimization phase is also proposed to significantly reduce the variance
of the solutions returned by the algorithm. In addition, based on the RSPG
algorithm, a stochastic gradient free algorithm, which only uses the stochastic
zeroth-order information, has been also discussed. Some preliminary numerical
results are also provided.


title: The Church of the Symmetric Subspace

abstract:
  The symmetric subpace has many applications in quantum information theory.
This review article begins by explaining key background facts about the
symmetric subspace from a quantum information perspective. Then we review, and
in some places extend, work of Werner and Chiribella that connects the
symmetric subspace to state estimation, optimal cloning, the de Finetti theorem
and other topics. In the third and final section, we discuss how the symmetric
subspace can yield concentration-of-measure results via the calculation of
higher moments of random quantum states.
  There are no new results in this article, but only some new proofs of
existing results, such as a variant of the exponential de Finetti theorem. The
purpose of the article is (a) pedagogical, and (b) to collect in one place
many, if not all, of the quantum information applications of the symmetric
subspace.


title: Weitzenboeck derivations of free metabelian associative algebras

abstract:
  By the classical theorem of Weitzenboeck the algebra of constants (i.e., the
kernel) of a nonzero locally nilpotent linear derivation of the polynomial
algebra K[X] in d variables over a field K of characteristic 0 is finitely
generated. As a noncommutative generalization one considers the algebra of
constants of a locally nilpotent linear derivation of a d-generated relatively
free algebra F(V) in a variety V of unitary associative algebras over K. It is
known that the algebra of constants of F(V) is finitely generated if and only
if V satisfies a polynomial identity which does not hold for the algebra of 2 x
2 upper triangular matrices. Hence the free metabelian associative algebra F(M)
is a crucial object to study. We show that the vector space of the constants in
the commutator ideal F'(M) is a finitely generated module of the algebra of
constants of the polynomial algebra K[U,V] in 2d variables, where the
derivation acts on U and V in the same way as on X. For small d, we calculate
the Hilbert series of the constants in F'(M) and find the generators of the
related module. This gives also an (infinite) set of generators of the algebra
of constants in F(M).


title: Sectional-Anosov flows in higher dimensions

abstract:
  A sectional-Anosov flow on a manifold M is a C^1 vector field inwardly
transverse to the boundary for which the maximal invariant is
sectional-hyperbolic. We prove that every attractor of every vector field C^1
close to a transitive sectional-Anosov flow with singularities on a compact
manifold has a singularity. This extends the three-dimensional result obtained
in [Morales, C.A., The explosion of singular-hyperbolic attractors].


title:
Calculations of the Propagated LIS Electron Spectrum Which Describe the
  Cosmic Ray Electron Spectrum below ~100 MeV Measured Beyond 122 AU at Voyager
  1 and its Relationship to the PAMELA Electron Spectrum above 200 MeV

abstract:
  The new Voyager measurements of cosmic ray electrons between 6-60 MeV beyond
122 AU are very sensitive indicators of cosmic ray propagation and acceleration
in the galaxy at a very low modulation level. Using a Monte Carlo diffusion
model with a source spectrum with a single spectral index of -2.2 at all
energies we are able to fit this observed Voyager spectrum and the contemporary
PAMELA electron spectrum over an energy range from 6 MeV to ~200 GeV. This
spectrum has a break in it but this break is due to propagation effects, not
changes in the primary spectrum. This break is gradual, starting at > 2 GeV
where the spectrum is ~E^-3.2 and continuing down to ~100 MeV or below where
the spectrum becomes ~E^-1.5. At the higher energies the loss terms due to
synchrotron radiation and inverse Compton effects which are ~E^2.0 steepen the
exponent of the source spectrum by 1.0. At lower energies, these terms become
unimportant and the loss is governed by diffusion and escape from the galaxy. A
diffusion term which is proportional to beta^-1 below ~0.32 GV (which also fit
the H and He spectra measured at Voyager) and has a value = 3x1028 cm^2 x s^-1
at 1 GV and a boundary at +/-1 Kpc will fit the Voyager or other similar
spectra at low energies.


title:
Cold ion-atom chemistry driven by spontaneous radiative relaxation: a
  case study for the formation of the YbCa^{+} molecular ion

abstract:
  Using both quantum and semi-classical methods, we calculate the rates for
radiative association and charge transfer in cold collisions of Yb+ with Ca.


title: Modified scattering for the Boson Star Equation

abstract:
  We consider the question of scattering for the boson star equation in three
space dimensions. This is a semi-relativistic Klein-Gordon equation with a
cubic nonlinearity of Hartree type. We combine weighted estimates, obtained by
exploiting a special null structure present in the equation, and a refined
asymptotic analysis performed in Fourier space, to obtain global solutions
evolving from small and localized Cauchy data. We describe the behavior at
infinity of such solutions by identifying a suitable nonlinear asymptotic
correction to scattering. As a byproduct of the weighted energy estimates
alone, we also obtain global existence and (linear) scattering for solutions of
semi-relativistic Hartree equations with potentials decaying faster than
Coulomb.


title: Boosting Top Partner Searches in Composite Higgs Models

abstract:
  Fermionic third generation top partners are generic in composite Higgs
models. They are likely to decay into third generation quarks and electroweak
bosons. We propose a novel cut-and-count-style analysis in which we cross
correlate the model-dependent single and model-independent pair production
processes for the top partners $X_{5/3}$ and $B$. In the class of composite
Higgs models we study, $X_{5/3}$ is very special as it is the lightest exotic
fermion. A constraint on the mass of $X_{5/3}$ directly extends to constrains
on all top partner masses. By combining jet substructure methods with
conventional reconstruction techniques we show that in this kind of final state
a smooth interpolation between the boosted and unboosted regime is possible. We
find that a reinterpretation of existing searches can improve bounds on the
parameter space of composite Higgs models. Further, at 8 TeV a combined search
for $X_{5/3}$ and $B$ in the $l+\rm{jets}$ final state can be more sensitive
than a search involving same-sign dileptons.


title: Free structures in division rings

abstract:
  Makar-Limanov's conjecture states that if a division ring D is finitely
generated and infinite dimensional over its center k then D contains a free
k-subalgebra of rank 2. In this work, we will investigate the existence of such
structures in D, the division ring of fractions of the skew polynomial ring
L[t;\sigma], where t is a variable and $\sigma$ is a k-automorphism of L. For
instance, we prove Makar-Limanov's conjecture when either L is the function
field of an abelian variety or the function field of the n-dimensional
projective space.


title: Duality Constraints on String Theory: Instantons and spectral networks

abstract:
  We study an implication of $p-q$ duality (spectral duality or T-duality) on
non-perturbative completion of $(p,q)$ minimal string theory. According to the
Eynard-Orantin topological recursion, spectral $p-q$ duality was already
checked for all-order perturbative analysis including instanton/soliton
amplitudes. Non-perturbative realization of this duality, on the other hand,
causes a new fundamental issue. In fact, we find that not all the
non-perturbative completions are consistent with non-perturbative $p-q$
duality; Non-perturbative duality rather provides a constraint on
non-perturbative contour ambiguity (equivalently, of D-instanton fugacity) in
matrix models. In particular, it prohibits some of meta-stability caused by
ghost D-instantons, since there is no non-perturbative realization on the dual
side in the matrix-model description. Our result is the first quantitative
observation that a missing piece of our understanding in non-perturbative
string theory is provided by the principle of non-perturbative string duality.
To this end, we study Stokes phenomena of $(p,q)$ minimal strings with spectral
networks and improve the Deift-Zhou's method to describe meta-stable vacua. By
analyzing the instanton profile on spectral networks, we argue the duality
constraints on string theory.


title:
A smart local moving algorithm for large-scale modularity-based
  community detection

abstract:
  We introduce a new algorithm for modularity-based community detection in
large networks. The algorithm, which we refer to as a smart local moving
algorithm, takes advantage of a well-known local moving heuristic that is also
used by other algorithms. Compared with these other algorithms, our proposed
algorithm uses the local moving heuristic in a more sophisticated way. Based on
an analysis of a diverse set of networks, we show that our smart local moving
algorithm identifies community structures with higher modularity values than
other algorithms for large-scale modularity optimization, among which the
popular 'Louvain algorithm' introduced by Blondel et al. (2008). The
computational efficiency of our algorithm makes it possible to perform
community detection in networks with tens of millions of nodes and hundreds of
millions of edges. Our smart local moving algorithm also performs well in small
and medium-sized networks. In short computing times, it identifies community
structures with modularity values equally high as, or almost as high as, the
highest values reported in the literature, and sometimes even higher than the
highest values found in the literature.


title:
Niobium-based sputtered thin films for Corrosion Protection of
  proton-irradiated liquid water targets for [18F] production

abstract:
  Chemically inert Coatings on Havar entrance foils of the targets for [18F]
production via proton irradiation of enriched water at pressurized conditions
are needed to decrease the amount of ionic contaminants released from Havar. In
order to find the most effective protective coatings, the Nb-based coating
microstructure and barrier properties have been correlated with deposition
parameters as: substrate temperature, applied bias, deposition rate and
sputtering gas pressure. Aluminated quartz used as a substrate allowed us to
verify the protection efficiency of the desirable coatings as diffusion
barriers. Two modeling corrosion tests based on the extreme susceptibility of
aluminum to liquid gallium and acid corrosion were applied. Pure Niobium
coatings have been found less effective barriers than Niobium-titanium
coatings. But Niobium oxide films, according to the corrosion tests performed,
showed superior barrier properties. Therefore Multi-layered Niobium-Niobium
oxide films have been suggested, since they combine the high thermal
conductivity of Niobium with the good barrier properties of Niobium oxide.


title:
On the Typical Size and Cancelations Among the Coefficients of Some
  Modular Forms

abstract:
  We obtain a nontrivial upper bound for almost all elements of the sequences
of real numbers which are multiplicative and at the prime indices are
distributed according to the Sato--Tate density. Examples of such sequences
come from coefficients of several $L$-functions of elliptic curves and modular
forms. In particular, we show that $|\tau(n)|\le n^{11/2} (\log n)^{-1/2+o(1)}$
for a set of $n$ of asymptotic density 1, where $\tau(n)$ is the Ramanujan
$\tau$ function while the standard argument yields $\log 2$ instead of $-1/2$
in the power of the logarithm. Another consequence of our result is that in the
number of representations of $n$ by a binary quadratic form one has slightly
more than square-root cancellations for almost all integers $n$.
  In addition we obtain a central limit theorem for such sequences, assuming a
weak hypothesis on the rate of convergence to the Sato--Tate law. For Fourier
coefficients of primitive holomorphic cusp forms such a hypothesis is known
conditionally assuming the automorphy of all symmetric powers of the form and
seems to be within reach unconditionally using the currently established
potential automorphy.


title: On H\"older continuity of the solution of stochastic wave equations

abstract:
  In this paper, we study the stochastic wave equations in the spatial
dimension 3 driven by a Gaussian noise which is white in time and correlated in
space. Our main concern is the sample path H\"older continuity of the solution
both in time variable and in space variables. The conditions are given either
in terms of the mean H\"older continuity of the covariance function or in terms
of its spectral measure. Some examples of the covariance functions are proved
to satisfy our conditions, which include the case of the work \cite{dalang4}.
In particular, we obtain the H\"older continuity results for the solution of
the stochastic wave equations driven by (space inhomogeneous) fractional
Brownian noises. For this particular noise, the optimality of the obtained
H\"older exponents is also discussed.


title:
Large-scale alignments of quasar polarisations: a detailed study of the
  spinless-particle scenario

abstract:
  The main motivation for our work has been a puzzling observation concerning
quasars. No one expected the existence of correlations in the polarisation of
visible light coming from objects separated by gigaparsecs, until they were
first reported in the form of a redshift-dependent effect that has become more
and more significant with the growth of the data sample.
  In close connection with the observational group, we have studied in detail
the most widely considered scenario, involving axion-photon mixing in
extragalactic magnetic fields.
  After a systematic investigation, we conclude that it is very unlikely that
these observations can be accounted for by axion-like particles, given current
data and constraints. We also derive new limits on the parameters describing
these particles.
  This thesis gives in particular a detailed account of the consequences of
axion-photon mixing on polarisation, studies the influence of averages over the
frequency (including a wave-packet treatment of the mixing), and discusses the
consequences of different magnetic-field morphologies.


title:
Ultrafast, green third-harmonic generation and strong-field phenomena in
  silicon-on-insulator nanoplasmonic waveguides

abstract:
  The emergence of strong-field nanoplasmonics brings extreme laser
field-matter interaction into the realm of nanoscale science, unveiling
exciting new physics. Highly nonlinear interaction is enabled by tightly
confined electric fields in nanoplasmonic structures, permitting use of optical
fields from low-power laser oscillators. Here, we report the first
demonstration of visible 517nm third harmonic generation in ultracompact
nanoplasmonic waveguides on a silicon-on-insulator platform at an unprecedented
conversion efficiency of ~10^{-5}. Exponential growth of broadband white light
generation confirms a new strong-field phenomenon of ponderomotive force-driven
electron avalanche multiplication. Using time-resolved experiments, we show
that the strong nanoplasmonic field confinement allows nonlinear interaction to
occur on an ultrafast timescale of 1.98 +/- 0.40 ps, despite the long
free-carrier lifetime in silicon. These findings uncover a new strong-field
interaction that can be used in sensitive nanoplasmonic modulators and hybrid
plasmonic-electronic transducers.


title:
Electronic and optical gap renormalization in carbon nanotubes near a
  metallic surface

abstract:
  Renormalization of quasiparticles and excitons in carbon nanotubes (CNTs)
near a metallic surface has been studied within a many-body formalism using an
embedding approach newly implemented in the GW and Bethe-Salpeter methods. The
quasiparticle bandgap renormalization in semiconducting CNTs is found to scale
as -1/(2h_a), with h_a the apparent nanotube height, and it can exceed half an
eV. Also, the binding energy of excitons is reduced dramatically -by as much as
75%- near the surface. Compensation between quasiparticle and excitonic effects
results in small changes in the optical gap. The important role played by the
nanotube screening response in establishing these effects is emphasized and a
simple electrostatic model with no adjustable parameters explains the results
of state-of-the-art calculations and generalizes them to a large variety of
CNTs.


title: The two-color Soergel calculus

abstract:
  We give a diagrammatic presentation for the category of Soergel bimodules for
the dihedral group W . The (two-colored) Temperley-Lieb category is embedded
inside this category as the degree 0 morphisms between color-alternating
objects. The indecomposable Soergel bimodules are the images of Jones-Wenzl
projectors. When W is infinite, the parameter q of the Temperley-Lieb algebra
may be generic, yielding a quantum version of the geometric Satake equivalence
for sl(2). When W is finite, q must be specialized to an appropriate root of
unity, and the negligible Jones-Wenzl projector yields the Soergel bimodule for
the longest element of W .


title: A complete demonstrator of a muon cooled Higgs factory

abstract:
  The recent discovery of the Higgs particle of 125 GeV has revised the
interest of the so-called Higgs factory, namely of a mu+mu- collider with
adequately cooled intensity of about 6 10^12 muons of each sign, a repetition
rate of 15-50 p/s and a luminosity of up to 10^32 cm-2 s-1. The process is the
direct production of a H_0 scalar in the s-state. Its partial widths can be
studied in clean conditions and with remarkable accuracy. The Ho mass itself
can be measured to about +-100 keV (deltaE/E <10^-6) in the (WW) channel with
the help of the decay frequency of the polarized mu->e nu nu decay electrons.
  The realization of a cascade of unconventional but very small rings of few
meters radius is described, in order to achieve the required longitudinal and
transverse emittances. Physics requirements and the many studies already
undertaken suggest that the next step, prior to but adequate for a H_0 physics
programme, could be the practical realization of a full scale muon cooling
demonstrator. The correct operation of the demonstrator may be initially
explored with the help of very low intensity muon beam already available in a
number of different accelerators.
  The additional but relatively conventional components necessary to realize
the facility with the appropriate luminosity should be constructed only after
the success of this initial cooling experiment has been conclusively
demonstrated. The ultimate mu+mu- collider for a Higgs Factory can be situated
within the existing CERN or FNAL sites.


title: Finitely Supported *-Simple Complete Ideals in a Regular Local Ring

abstract:
  Let I be a finitely supported complete m-primary ideal of a regular local
ring (R, m). A theorem of Lipman implies that I has a unique factorization as a
*-product of special *-simple complete ideals with possibly negative exponents
for some of the factors. The existence of negative exponents occurs if the
dimension of R is at least 3 because of the existence of finitely supported
*-simple ideals that are not special. We consider properties of special
*-simple complete ideals such as their Rees valuations and point basis. Let (R,
m) be a d-dimensional equicharacterstic regular local ring with m = (x_1, ...,
x_d)R. We define monomial quadratic transforms of R and consider transforms and
inverse transforms of monomial ideals. For a large class of monomial ideals I
that includes complete inverse transforms, we prove that the minimal number of
generators of I is completely determined by the order of I. We give necessary
and sufficient conditions for the complete inverse transform of a *-product of
monomial ideals to be the *-product of the complete inverse transforms of the
factors. This yields examples of finitely supported *-simple monomial ideals
that are not special. We prove that a finitely supported *-simple monomial
ideal with linearly ordered base points is special *-simple.


title: The sharp estimates on the orthogonal polynomials from the Steklov class

abstract:
  We obtain the sharp lower bound for the uniform norm of the orthogonal
polynomials in the Steklov class. We also prove the sharp estimates for the
polynomial entropy in this class.


title: Contracting Boundaries of CAT(0) Spaces

abstract:
  As demonstrated by Croke and Kleiner, the visual boundary of a CAT(0) group
is not well-defined since quasi-isometric CAT(0) spaces can have
non-homeomorphic boundaries. We introduce a new type of boundary for a CAT(0)
space, called the contracting boundary, made up rays satisfying one of five
hyperbolic-like properties. We prove that these properties are all equivalent
and that the contracting boundary is a quasi-isometry invariant. We use this
invariant to distinguish the quasi-isometry classes of certain right-angled
Coxeter groups.


title:
Development of a finite element firn densification model for converting
  volume changes to mass changes

abstract:
  In regions where ice sheets are increasing in mass, there is a 50-200 m layer
of old snow called firn which does not melt in the summer months. The density
of firn tracks the transformation of snow into glacial ice at approximately 917
kg m^-3. The process of firn densification is important in at least two ways:
1) it can be a dominant component in the observed rate of change of the surface
elevation, and 2) storage of liquid water in the lower density firn layer is
now considered a critical component in the mass balance of ice sheets. If the
rate of change of surface elevation can be equated with the rate of change in
the mass of the ice sheet, we would have an excellent means of monitoring ice
sheet mass balance. However, knowledge of firn densification rates is needed to
make the inference of mass rate of change from volume rate of change. Several
firn models have been created for areas without melt. We have reformulated
these models with the finite-element software package FEniCS and integrated
them with an enthalpy-formulation. This integration allows us to account for
the melting and subsequent re-freezing of firn layers into ice lenses.


title:
Calibrations of Atmospheric Parameters Obtained from the First Year of
  SDSS-III APOGEE Observations

abstract:
  The SDSS-III Apache Point Observatory Galactic Evolution Experiment (APOGEE)
is a three year survey that is collecting 100,000 high-resolution spectra in
the near-IR across multiple Galactic populations. To derive stellar parameters
and chemical compositions from this massive data set, the APOGEE Stellar
Parameters and Chemical Abundances Pipeline (ASPCAP) has been developed. Here,
we describe empirical calibrations of stellar parameters presented in the first
SDSS-III APOGEE data release (DR10). These calibrations were enabled by
observations of 559 stars in 20 globular and open clusters. The cluster
observations were supplemented by observations of stars in NASA's Kepler field
that have well determined surface gravities from asteroseismic analysis. We
discuss the accuracy and precision of the derived stellar parameters,
considering especially effective temperature, surface gravity, and metallicity;
we also briefly discuss the derived results for the abundances of the
alpha-elements, carbon, and nitrogen. Overall, we find that ASPCAP achieves
reasonably accurate results for temperature and metallicity, but suffers from
systematic errors in surface gravity. We derive calibration relations that
bring the raw ASPCAP results into better agreement with independently
determined stellar parameters. The internal scatter of ASPCAP parameters within
clusters suggests that, metallicities are measured with a precision better than
0.1 dex, effective temperatures better than 150 K, and surface gravities better
than 0.2 dex. The understanding provided by the clusters and Kepler giants on
the current accuracy and precision will be invaluable for future improvements
of the pipeline.


title:
Long-range rapidity correlations in high energy AA collisions in Monte
  Carlo model with string fusion

abstract:
  The magnitude of long-range correlations between observables in two separated
rapidity windows, proposed as a signature of the string fusion and percolation
phenomenon, is studied in the framework of non-Glauber Monte Carlo
string-parton model, based on the picture of elementary collisions of color
dipoles. The predictions, obtained with and without string fusion, demonstrate
effects of color string fusion on the observables in Pb-Pb collisions at the
LHC: decrease of n-n correlation coefficient with centrality and negative pt-n
correlations, if the sufficiently effective centrality estimator is applied. In
general case it is shown that the values of n-n and pt-n correlation
coefficients strongly depend on the method of collision centrality fixation. In
contrast, the predictions obtained for pt-pt correlation have almost no effect
of centrality determination method and the corresponding experimental data
would produce the strong limitation on the transverse radius of a string.


title:
Backward stochastic differential equation approach to modeling of gene
  expression

abstract:
  In this article, we introduce a novel backward method to model stochastic
gene expression and protein level dynamics. The protein amount is regarded as a
diffusion process and is described by a backward stochastic differential
equation (BSDE). Unlike many other SDE techniques proposed in the literature,
the BSDE method is backward in time; that is, instead of initial conditions it
requires the specification of endpoint ("final") conditions, in addition to the
model parametrization. To validate our approach we employ Gillespie's
stochastic simulation algorithm (SSA) to generate (forward) benchmark data,
according to predefined gene network models. Numerical simulations show that
the BSDE method is able to correctly infer the protein level distributions that
preceded a known final condition, obtained originally from the forward SSA.
This makes the BSDE method a powerful systems biology tool for time reversed
simulations, allowing, for example, the assessment of the biological conditions
(e.g. protein concentrations) that preceded an experimentally measured event of
interest (e.g. mitosis, apoptosis, etc.).


title: Collective symplectic integrators

abstract:
  We construct symplectic integrators for Lie-Poisson systems. The integrators
are standard symplectic (partitioned) Runge--Kutta methods. Their phase space
is a symplectic vector space with a Hamiltonian action with momentum map $J$
whose range is the target Lie--Poisson manifold, and their Hamiltonian is
collective, that is, it is the target Hamiltonian pulled back by $J$. The
method yields, for example, a symplectic midpoint rule expressed in 4 variables
for arbitrary Hamiltonians on $\mathfrak{so}(3)^*$. The method specializes in
the case that a sufficiently large symmetry group acts on the fibres of $J$,
and generalizes to the case that the vector space carries a bifoliation.
Examples involving many classical groups are presented.


title: Number of permutations with same peak set for signed permutations

abstract:
  A signed permutation \pi = \pi_1\pi_2 \ldots \pi_n in the hyperoctahedral
group B_n is a word such that each \pi_i \in {-n, \ldots, -1, 1, \ldots, n} and
{|\pi_1|, |\pi_2|, \ldots, |\pi_n|} = {1,2,\ldots,n}. An index i is a peak of
\pi if \pi_{i-1}<\pi_i>\pi_{i+1} and P_B(\pi) denotes the set of all peaks of
\pi. Given any set S, we define P_B(S,n) to be the set of signed permutations
\pi \in B_n with P_B(\pi) = S. In this paper we are interested in the
cardinality of the set P_B(S,n). In 2012, Billey, Burdzy and Sagan investigated
the analogous problem for permutations in the symmetric group, S_n. In this
paper we extend their results to the hyperoctahedral group; in particular we
show that #P_B(S,n) = p(n)2^{2n-|S|-1} where p(n) is the same polynomial found
in by Billey, Burdzy and Sagan which leads to the explicit computation of
interesting special cases of the polynomial p(n). In addition we have extended
these results to the case where we add \pi_0=0 at the beginning of the
permutations, which gives rise to the possibility of a peak at position 1, for
both the symmetric and the hyperoctahedral groups.


title:
Time-resolved broadband Raman spectroscopies; A unified six-wave-mixing
  representation

abstract:
  Excited-state vibrational dynamics in molecules can be studied by an
electronically off-resonant Raman process induced by a probe pulse with
variable delay with respect to an actinic pulse. We establish the connection
between several variants of the technique that involve either spontaneous or
stimulated Raman detection and different pulse configurations. By using loop
diagrams in the frequency domain we show that all signals can be described as
six wave mixing which depend on the same four point molecular correlation
functions involving two transition dipoles and two polarizabilities and
accompanied by a different gating. Simulations for the stochastic
two-state-jump model illustrate the origin of the absorptive and dispersive
features observed experimentally.


title:
Exact solutions of multicomponent nonlinear Schr\"odinger equations
  under general plane-wave boundary conditions

abstract:
  We construct exact soliton solutions of integrable multicomponent nonlinear
Schr\"odinger (NLS) equations under general nonvanishing boundary conditions.
Different components of the vector (or matrix) dependent variable can approach
plane waves with different wavenumbers and frequencies at spatial infinity. We
apply B\"acklund-Darboux transformations to the cubic NLS equations with a
self-focusing nonlinearity, a self-defocusing nonlinearity or a mixed
focusing-defocusing nonlinearity. Both bright-soliton solutions and
dark-soliton solutions are obtained, depending on the signs of the nonlinear
terms and the type of B\"acklund-Darboux transformation. The multicomponent
solitons generally possess internal degrees of freedom and provide highly
nontrivial generalizations of the scalar NLS solitons. The main step in the
construction of the multicomponent solitons is to compute the matrix
exponential of a constant non-diagonal matrix arising from the Lax pair. With a
suitable re-parametrization of the non-diagonal matrix, the matrix exponential
can be computed explicitly in closed form for the most interesting cases such
as the two-component vector NLS equation. In particular, we do not resort to
Cardano's formula in diagonalizing a $3 \times 3$ matrix, so our expressions
for the multicomponent solitons are in some sense more explicit and useful than
those obtained in [Q-H. Park and H. J. Shin, Phys. Rev. E 61 (2000) 3093].


title: Associated Forms in Classical Invariant Theory

abstract:
  It was conjectured in a recent article by M. Eastwood and the second author
that all absolute classical invariants of forms of degree $m\ge 3$ on ${\mathbb
C}^n$ can be extracted, in a canonical way, from those of forms of degree
$n(m-2)$ by means of assigning every form with non-vanishing discriminant the
so-called associated form. In that paper, this surprising conjecture was
confirmed for binary forms of degree $m \le 6$ and ternary cubics. In the
present article, we settle the conjecture in full generality. In addition, we
propose a stronger version of this statement and obtain evidence supporting it.


title:
Vector-like technineutron Dark Matter: is a QCD-type Technicolor ruled
  out by XENON100?

abstract:
  We continue to explore a question about the existence of a new strongly
coupled dynamics above the electroweak scale. The latter has been recently
realized in the simplest consistent scenario, the vector-like (or
chiral-symmetric) Technicolor model based upon the gauged linear sigma-model.
One of the predictions of a new strong dynamics in this model, the existence of
stable vector-like technibaryon states at a TeV scale, such that the lightest
neutral one could serve as a Dark Matter candidate. Here, we consider the
QCD-type Technicolor with SU(3)_TC confined group and one SU(2)_W doublet of
vector-like techniquarks and test this model against existing Dark Matter
astrophysics data. We show that the spin-independent Dirac
technineutron-nucleon cross section is by far too large and ruled out by
XENON100 data. We conclude that vector-like techniquark sectors with an odd
group of confinement SU(2n+1)_TC, n=1,2,... and with ordinary vector-like weak
SU(2)_W interactions are excluded if the technibaryon number is conserved. We
discuss a possible generic TC scenario with a technibaryon sector interacting
via an extra vector SU(2)_V other than the standard weak SU(2)_W and consider
immediate implications for the cosmological evolution and freeze out of heavy
relic technineutrons.


title: Searching for the core variables in principal components analysis

abstract:
  In this article, we introduce a procedure for selecting variables in
principal components analysis. The procedure was developed to identify a small
subset of the original variables that best explain the principal components
through nonparametric relationships. There are usually some noisy uninformative
variables in a dataset, and some variables that are strongly related to each
other because of their general interdependence. The procedure is designed to be
used following the satisfactory initial use of a principal components analysis
with all variables, and its aim is to help to interpret underlying structures.
We analyze the asymptotic behavior of the method and provide some examples.


title:
Expand and Contract: Sampling graphs with given degrees and other
  combinatorial families

abstract:
  Sampling from combinatorial families can be difficult. However, complicated
families can often be embedded within larger, simpler ones, for which easy
sampling algorithms are known. We take advantage of such a relationship to
describe a sampling algorithm for the smaller family, via a Markov chain
started at a random sample of the larger family. The utility of the method is
demonstrated via several examples, with particular emphasis on sampling
labelled graphs with given degree sequence, a well-studied problem for which
existing algorithms leave much room for improvement. For graphs with given
degrees, with maximum degree $O(m^{1/4})$ where $m$ is the number of edges, we
obtain an asymptotically uniform sample in $O(m)$ steps, which substantially
improves upon existing algorithms.


title:
Joint Video and Text Parsing for Understanding Events and Answering
  Queries

abstract:
  We propose a framework for parsing video and text jointly for understanding
events and answering user queries. Our framework produces a parse graph that
represents the compositional structures of spatial information (objects and
scenes), temporal information (actions and events) and causal information
(causalities between events and fluents) in the video and text. The knowledge
representation of our framework is based on a spatial-temporal-causal And-Or
graph (S/T/C-AOG), which jointly models possible hierarchical compositions of
objects, scenes and events as well as their interactions and mutual contexts,
and specifies the prior probabilistic distribution of the parse graphs. We
present a probabilistic generative model for joint parsing that captures the
relations between the input video/text, their corresponding parse graphs and
the joint parse graph. Based on the probabilistic model, we propose a joint
parsing system consisting of three modules: video parsing, text parsing and
joint inference. Video parsing and text parsing produce two parse graphs from
the input video and text respectively. The joint inference module produces a
joint parse graph by performing matching, deduction and revision on the video
and text parse graphs. The proposed framework has the following objectives:
Firstly, we aim at deep semantic parsing of video and text that goes beyond the
traditional bag-of-words approaches; Secondly, we perform parsing and reasoning
across the spatial, temporal and causal dimensions based on the joint S/T/C-AOG
representation; Thirdly, we show that deep joint parsing facilitates subsequent
applications such as generating narrative text descriptions and answering
queries in the forms of who, what, when, where and why. We empirically
evaluated our system based on comparison against ground-truth as well as
accuracy of query answering and obtained satisfactory results.


title:
A volume-of-fluid formulation for the study of co-flowing fluids
  governed by the Hele-Shaw equations

abstract:
  We present a computational framework to address the flow of two immiscible
viscous liquids which co-flow into a shallow rectangular container at one side,
and flow out into a holding container at the opposite side. Assumptions based
on the shallow depth of the domain are used to reduce the governing equations
to one of Hele-Shaw type. The distinctive feature of the numerical method is
the accurate modeling of the capillary effects. A continuum approach coupled
with a volume-of-fluid formulation for computing the interface motion and for
modeling the interfacial tension in Hele-Shaw flows is formulated and
implemented. The interface is reconstructed with a height-function algorithm.
The combination of these algorithms is a novel development for the
investigation of Hele-Shaw flows. The order of accuracy and convergence
properties of the method are discussed with benchmark simulations. A
microfluidic flow of a ribbon of fluid which co-flows with a second liquid is
simulated. We show that for small capillary numbers of O(0.01), there is an
abrupt change in interface curvature and focusing occurs close to the exit.


title: A 331 WIMPy Dark Radiation Model

abstract:
  Recent observations suggest that the number of relativistic degrees of
freedom in the early universe might exceed what is predicted in the standard
cosmological model. If even a small, percent-level fraction of dark matter
particles are produced relativistically, they could mimic the effect of an
extra realistic species at matter-radiation equality while obeying BBN, CMB and
Structure Formation bounds. We show that this scenario is quite naturally
realized with a weak-scale dark matter particle and a high-scale ``mother''
particle within a well motivated 3-3-1 gauge model, which is particularly
interesting for being consistent with electroweak precision measurements, with
recent LHC results, and for offering a convincing explanation for the number of
generations in the Standard Model.


title:
Applicability of the Newman-Janis Algorithm to Black Hole Solutions of
  Modified Gravity Theories

abstract:
  The Newman-Janis algorithm has been widely used to construct rotating black
hole solutions from non-rotating counterparts. While this algorithm was
developed within General Relativity, it has more recently been applied to
non-rotating solutions in modified gravity theories. We find that the
application of the Newman-Janis algorithm to an arbitrary non-GR
spherically-symmetric solution introduces pathologies in the resulting
axially-symmetric metric. This then establishes that, in general, the
Newman-Janis algorithm should not used to construct rotating black hole
solutions outside of General Relativity.


title:
A free energy satisfying finite difference method for
  Poisson--Nernst--Planck equations

abstract:
  In this work we design and analyze a free energy satisfying finite difference
method for solving Poisson-Nernst-Planck equations in a bounded domain. The
algorithm is of second order in space, with numerical solutions satisfying all
three desired properties: i) mass conservation, ii) positivity preserving, and
iii) free energy satisfying in the sense that these schemes satisfy a discrete
free energy dissipation inequality. These ensure that the computed solution is
a probability density, and the schemes are energy stable and preserve the
equilibrium solutions. Both one and two-dimensional numerical results are
provided to demonstrate the good qualities of the algorithm, as well as effects
of relative size of the data given.


title:
Cross-Correlation of Photovoltaic Output Fluctuation in Power System
  Operation for Large-Scale Photovoltaic Integration

abstract:
  We analyzed the cross-correlation of Photovoltaic (PV) output fluctuation for
the actual PV output time series data in both the Tokyo area and the whole of
Japan using the principal component analysis with the random matrix theory.
Based on the obtained cross-correlation coefficients, the forecast error for PV
output was estimated with/without considering the cross-correlations. Then
operation schedule of thermal plants is calculated to integrate PV output using
our unit commitment model with the estimated forecast error. The cost for grid
integration of PV system was also estimated. Finally, validity of the concept
of "local production for local consumption of renewable energy" and alternative
policy implications were also discussed.


title:
A priorconditioned LSQR algorithm for linear ill-posed problems with
  edge-preserving regularization

abstract:
  This article presents a method for solving large-scale linear inverse
problems regular- ized with a nonlinear, edge-preserving penalty term such as
the total variation or Perona-Malik. In the proposed scheme, the nonlinearity
is handled with lagged diffusivity fixed point iteration which involves solving
a large-scale linear least squares problem in each iteration. Because the
convergence of Krylov methods for problems with discontinuities is notoriously
slow, we propose to accelerate it by means of priorconditioning.
Priorconditioning is a technique which embeds the information contained in the
prior (expressed as a regularizer in Bayesian framework) directly into the
forward operator and hence into the solution space. We derive a
factorization-free priorconditioned LSQR algorithm, allowing implicit
application of the preconditioner through efficient schemes such as multigrid.
The resulting method is matrix-free i.e. the forward map can be defined through
its action on a vector. We demonstrate the effectiveness of the proposed scheme
on a three-dimensional problem in fluorescence diffuse optical tomography using
algebraic multigrid preconditioner.


title: Efficiently Listing Combinatorial Patterns in Graphs

abstract:
  Graphs are extremely versatile and ubiquitous mathematical structures with
potential to model a wide range of domains. For this reason, graph problems
have been of interest since the early days of computer science. Some of these
problems consider substructures of a graph that have certain properties. These
substructures of interest, generally called patterns, are often meaningful in
the domain being modeled. Classic examples of patterns include spanning trees,
cycles and subgraphs.
  This thesis focuses on the topic of explicitly listing all the patterns
existing in an input graph. One of the defining features of this problem is
that the number of patterns is frequently exponential on the size of the input
graph. Thus, the time complexity of listing algorithms is parameterized by the
size of the output.
  The main contribution of this work is the presentation of optimal algorithms
for four different problems of listing patterns in graphs, namely the listing
of k-subtrees, k-subgraphs, st-paths and cycles. The algorithms presented are
framed within the same generic approach, based in a recursive partition of the
search space that divides the problem into subproblems. The key to an efficient
implementation of this approach is to avoid recursing into subproblems that do
not list any patterns. With this goal in sight, a dynamic data structure,
called the certificate, is introduced and maintained throughout the recursion.
Moreover, properties of the recursion tree and lower bounds on the number of
patterns are used to amortize the cost of the algorithm on the size of the
output.


title: Imaging electrical activity of neurons with metamaterial nanosensors

abstract:
  A technology for recording electrical activity of large neuron populations at
arbitrary depth in brain tissues with less than cell spatial and millisecond
temporal resolutions was the most craving dream of neuroscientists and a long
pursued goal of engineers for decades. Even though many imaging techniques have
been devised up to date, none of them is capable to deliver either
quantitatively valid data nor able to meet contradictory requirements posed for
sensors to be safe, non-invasive and reliably working either within cultured
cell populations or during chronic implantations in vivo. In my research
project, I design and justify a novel nanobiosensors, capable to detect and
optically report the electric fields across cellular membrane and investigate
properties of that specially engineered plasmonic nanoantennas. In the
following literature survey, I observe the current state of electrophysiology
methods and after recalling the basics of fluorescence, discuss benefits and
drawbacks of today's voltage sensitive labelling and electric fields imaging
methods. This review is wrapped up by a brief outlook of prospective
applications of this technology.

categories: physics.bio-ph cond-mat.mtrl-sci physics.optics q-bio.NC


title: DIS and Beyond

abstract: A digest of my closing overview talk at DIS2013


title:
Constraining the dark cusp in the Galactic Center by long-period
  binaries

abstract:
  Massive black holes (MBHs) in galactic nuclei are believed to be surrounded
by a high density stellar cluster, whose mass is mostly in hard-to-detect faint
stars and compact remnants. Such dark cusps dominate the dynamics near the MBH:
a dark cusp in the Galactic center (GC) of the Milky Way would strongly affect
orbital tests of General Relativity there; on cosmic scales, dark cusps set the
rates of gravitational wave emission events from compact remnants that spiral
into MBHs, and they modify the rates of tidal disruption events, to list only
some implications. A recently discovered long-period massive young binary (P_12
<~ 1 yr, M_12 ~ O(100 M_sun), T_12 ~ 6x10^6 yr), only ~0.1 pc from the Galactic
MBH (Pfuhl et al 2013), sets a lower bound on the 2-body relaxation timescale
there, min t_rlx ~ (P_12/M_12)^(2/3)T_12 ~ 10^7 yr, and correspondingly, an
upper bound on the stellar number density, max n ~ few x 10^8/<M_star^2>
1/pc^3, based on the binary's survival against evaporation by the dark cusp.
However, a conservative dynamical estimate, the drain limit, implies t_rlx >
O(10^8) yr. Such massive binaries are thus too short-lived and tightly bound to
constrain a dense relaxed dark cusp. We explore here in detail the use of
longer-period, less massive and longer-lived binaries (P_12 ~ few yr, M_12 ~
2-4 M_sun, T_12 ~ 10^8-10^10 yr), presently just below the detection threshold,
for probing the dark cusp, and develop the framework for translating their
future detections among the giants in the GC into dynamical constraints.


title: Unstable supercritical discontinuous percolation transitions

abstract:
  The location and nature of the percolation transition in random networks is a
subject of intense interest. Recently, a series of graph evolution processes
have been introduced that lead to discontinuous percolation transitions where
the addition of a single edge causes the size of the largest component to
exhibit a significant macroscopic jump in the thermodynamic limit. These
processes can have additional exotic behaviors, such as displaying a `Devil's
staircase' of discrete jumps in the supercritical regime. Here we investigate
whether the location of the largest jump coincides with the percolation
threshold for a range of processes, such as Erdos-Renyi percolation,
percolation via edge competition and via growth by overtaking. We find that the
largest jump asymptotically occurs at the percolation transition for
Erdos-Renyi and other processes exhibiting global continuity, including models
exhibiting an `explosive' transition. However, for percolation processes
exhibiting genuine discontinuities, the behavior is substantially richer. In
percolation models where the order parameter exhibits a staircase, the largest
discontinuity generically does not coincide with the percolation transition.
For the generalized Bohman-Frieze-Wormald model, it depends on the model
parameter. Distinct parameter regimes well in the supercritical regime feature
unstable discontinuous transitions, which is a novel and unexpected phenomenon
in percolation. We thus demonstrate that seemingly and genuinely discontinuous
percolation transitions can involve a rich behavior in supercriticality, a
regime that has been largely ignored in percolation.


title: Performance Evaluation of BPM System in SSRF Using PCA Method

abstract:
  The beam position monitor (BPM) system is of most importance in a light
source. The capability of the BPM depends on the resolution of the system. The
traditional standard deviation on the raw data method merely gives the upper
limit of the resolution. Principal component analysis (PCA) had been introduced
in the accelerator physics and it could be used to get rid of the actual
signals. Beam related informations were extracted before the evaluation of the
BPM performance. A series of studies had been made in Shanghai Synchrotron
Radiation Facility (SSRF) and PCA was proved as an effective and robust method
in the performance evaluations of our BPM system.


title:
Local Average Consensus in Distributed Measurement of Spatial-Temporal
  Varying Parameters: 1D Case

abstract:
  We study a new variant of consensus problems, termed `local average
consensus', in networks of agents. We consider the task of using sensor
networks to perform distributed measurement of a parameter which has both
spatial (in this paper 1D) and temporal variations. Our idea is to maintain
potentially useful local information regarding spatial variation, as contrasted
with reaching a single, global consensus, as well as to mitigate the effect of
measurement errors. We employ two schemes for computation of local average
consensus: exponential weighting and uniform finite window. In both schemes, we
design local average consensus algorithms to address first the case where the
measured parameter has spatial variation but is constant in time, and then the
case where the measured parameter has both spatial and temporal variations. Our
designed algorithms are distributed, in that information is exchanged only
among neighbors. Moreover, we analyze both spatial and temporal frequency
responses and noise propagation associated with the algorithms. The tradeoffs
of using local consensus, as compared to standard global consensus, include
higher memory requirement and degraded noise performance. Arbitrary updating
weights and random spacing between sensors are analyzed in the proposed
algorithms.


title: Coping with qubit leakage in topological codes

abstract:
  Many physical systems considered promising qubit candidates are not, in fact,
two-level systems. Such systems can leak out of the preferred computational
states, leading to errors on any qubits that interact with leaked qubits.
Without specific methods of dealing with leakage, long-lived leakage can lead
to time-correlated errors. We study the impact of such time-correlated errors
on topological quantum error correction codes, which are considered highly
practical codes, using the repetition code as a representative case study. We
show that, under physically reasonable assumptions, a threshold error rate
still exists, however performance is significantly degraded. We then describe
simple additional quantum circuitry that, when included in the error detection
cycle, restores performance to acceptable levels.


title:
A high-order accurate accelerated direct solver for acoustic scattering
  from surfaces

abstract:
  We describe an accelerated direct solver for the integral equations which
model acoustic scattering from curved surfaces. Surfaces are specified via a
collection of smooth parameterizations given on triangles, a setting which
generalizes the typical one of triangulated surfaces, and the integral
equations are discretized via a high-order Nystrom method. This allows for
rapid convergence in cases in which high-order surface information is
available. The high-order discretization technique is coupled with a direct
solver based on the recursive construction of scattering matrices. The result
is a solver which often attains $O(N^{1.5})$ complexity in the number of
discretization nodes $N$ and which is resistant to many of the pathologies
which stymie iterative solvers in the numerical simulation of scattering. The
performance of the algorithm is illustrated with numerical experiments which
involve the simulation of scattering from a variety of domains, including one
consisting of a collection of 1000 ellipsoids with randomly oriented semiaxes
arranged in a grid, and a domain whose boundary has 12 curved edges and 8
corner points.


title:
Non-uniform sampled scalar diffraction calculation using non-uniform
  fast Fourier transform

abstract:
  Scalar diffraction calculations such as the angular spectrum method (ASM) and
Fresnel diffraction, are widely used in the research fields of optics, X-rays,
electron beams, and ultrasonics. It is possible to accelerate the calculation
using fast Fourier transform (FFT); unfortunately, acceleration of the
calculation of non-uniform sampled planes is limited due to the property of the
FFT that imposes uniform sampling. In addition, it gives rise to wasteful
sampling data if we calculate a plane having locally low and high spatial
frequencies. In this paper, we developed non-uniform sampled ASM and Fresnel
diffraction to improve the problem using the non-uniform FFT.


title:
On the crucial features of a single-file transport model for ion
  channels

abstract:
  It has long been accepted that the multiple-ion single-file transport model
is appropriate for many kinds of ion channels. However, most of the purely
theoretical works in this field did not capture all of the important features
of the realistic systems. Nowadays, large-scale atomic-level simulations are
more feasible. Discrepancy between theories, simulations and experiments are
getting obvious, enabling people to carefully examine the missing parts of the
theoretical models and methods. In this work, it is attempted to find out the
essential features that such kind of models should possess, in order that the
physical properties of an ion channel be adequately reflected.


title:
Point values and normalization of two-direction multiwavelets and their
  derivatives

abstract:
  Two-direction multiscaling functions $\boldsymbol{\phi}$ and two-direction
multiwavelets $\boldsymbol{\psi}$ associated with $\boldsymbol{\phi}$ are more
general and more flexible setting than one-direction multiscaling functions and
multiwavelets. In this paper, we investigate how to find and normalize point
values and those of derivatives of the two-direction multiscaling functions
$\boldsymbol{\phi}$ and multiwavelets $\boldsymbol{\psi}$. %associated with
$\boldsymbol{\phi}$. For finding point values, we investigate the eigenvalue
approach. For normalization, we investigate the normalizing conditions for them
by normalizing the zeroth continuous moment of $\boldsymbol{\phi}$. Examples
for illustrating the general theory are given.


title: Representing the "butterfly" projection in FITS - projection code XPH

abstract:
  The "butterfly" projection is constructed as the polar layout of the HEALPix
projection with (H,K) = (4,3). This short article formalises its representation
in FITS.


title: Fractal Transformations in 2 and 3 Dimensions

abstract:
  We present some work relating to fractal transformations on masked iterated
function systems and demonstrate how well known algorithms for generating
fractal transformations can be modifed for these systems. We also demonstrate
that these algorithms work equally well when applied to three dimensional data
sets and suggest some possible applications to special effects and modelling.


title:
The Nonlinear Asymptotic Stage of the Rayleigh-Taylor Instability with
  Wide Bubbles and Narrowing Spikes

abstract:
  The potential flow of an incompressible inviscid heavy fluid over a light one
is considered. The integral version of the method of matched asymptotic
expansion is applied to the construction of the solution over long intervals of
time. The asymptotic solution describes the flow in which a bubble rises with
constant speed and the "tongue" is in free fall. The outer expansion is
stationary, but the inner one depends on time. It is shown that the solution
exists within the same range of Froude number obtained previously by
Vanden-Broeck (1984a,b). The Froude number and the solution depend on the
initial energy of the disturbance. At the top of the bubble, the derivative of
the free-surface curvature has a discontinuity when the Froude number is not
equal to 0.23. This makes it possible to identify the choice of the solution
obtained in a number of studies with the presence of an artificial numerical
surface tension. The first correction term in the neighborhood of the tongue is
obtained when large surface tension is included.