title: Gluonic Effects on g-2: Holographic View

abstract:
  We study "gluonic effects" (gluon condensation effects) on the hadronic
leading order (HLO) contributions to the anomalous magnetic moment (g-2) of
leptons, based on a holographic model having explicit gluonic mode introduced
for consistency with the operator product expansion of QCD. We find gluonic
enhancement of HLO contributions to the muon g-2 by about 6%, which nicely
fills in the gap between the holographic estimate without gluonic effects and
the phenomenological one using the experimental data as inputs. Similar
calculations including the gluonic effects for the electron and the tau lepton
g-2 are also carried out in good agreement with the phenomenological estimates.
We then apply our holographic estimate to the Walking Technicolor (WTC) where
large techni-gluonic effects were shown to be vital for the Technidilaton,
(pseudo) Nambu-Goldstone boson of the (approximate) scale symmetry of WTC, to
be naturally as light as 125 GeV. It is shown that the value of the techni-HLO
contributions to the muon g-2 is 10-100 times enhanced by inclusion of the same
amount of the gluonic effects as that realizing the 125 GeV Technidilaton,
although such an enhanced techni-HLO contribution is still negligibly small
compared with the current deviation of the Standard Model prediction of the
muon g-2 from the experiments. The techni-HLO contributions to the tau lepton
g-2 is also discussed, suggesting a possible phenomenological relevance to be
tested by the future experiments.


title:
Strain tuning of optical emission energy and polarization in monolayer
  and bilayer MoS2

abstract:
  We use micro-Raman and photoluminescence (PL) spectroscopy at 300K to
investigate the influence of uniaxial tensile strain on the vibrational and
optoelectronic properties of monolayer and bilayer MoS2 on a flexible
substrate. The initially degenerate E^1_{2g} Raman mode is split into a doublet
as a direct consequence of the strain applied to MoS2 through Van der Waals
coupling at the sample-substrate interface. We observe a strong shift of the
direct band gap of 48meV/(% of strain) for the monolayer and 46meV/% for the
bilayer, whose indirect gap shifts by 86meV/%. We find a strong decrease of the
PL polarization linked to optical valley initialization for both monolayer and
bilayer samples, indicating that scattering to the spin-degenerate Gamma valley
plays a key role.


title: Growth rates of cocompact hyperbolic Coxeter groups and 2-Salem numbers

abstract:
  By the results of Cannon, Wagreich and Parry, it is known that the growth
rate of a cocompact Coxeter group in 2-dimensional hyperbolic space $H^2$ and
3-dimensional hyperbolic space $H^3$ is a Salem number. Kerada defined a
j-Salem number, which is a generalization of a Salem number. In this paper, we
realize infinitely many 2-Salem numbers as the growth rates of cocompact
Coxeter groups in 4-dimensional hyperbolic space $H ^4$. Our Coxeter polytopes
are constructed by successive gluing of Coxeter polytopes which we call Coxeter
dominoes.


title: Stability of super-Chandrasekhar magnetic white dwarfs

abstract:
  It has been recently proposed that very massive white dwarfs endowed with
strongly quantizing magnetic fields might be the progenitors of overluminous
type Ia supernovae like SN 2006gz and SN 2009dc. In this work, we show that the
onset of electron captures and pycnonuclear reactions in these putative
super-Chandrasekhar white dwarfs may severely limit their stability.


title: On the carbonaceous carriers of IR plateau and continuum emission

abstract:
  This study explores the molecular origins of plateaus and continuum
underlying IR and FIR bands emitted by compact nebulae, especially
proto-planetary nebulae. Computational organic chemistry codes are used to
deliver the vibrational integrated band intensities of various large, typical
carbonaceous structures. These spectra are composed of a rather continuous
distribution of weak modes from which emerge the fingerprints. The 6 to 18-mu
region is interspersed with a great many weak lines, to which the plateaus are
assigned. Similarly, the far IR spectrum is ascribed to the phonon (skeletal)
spectrum which is readily identified beyond 18 mu. The absorptivities and
absorption cross-sections per interstellar H atom deduced from these spectra
are comparable with those of laboratory dust analogs and astronomical
measurements, respectively. Moreover, the 5-35 mu spectra of two typical
Proto-Planetary Nebula were reasonably well simulated with combinations of
molecules containing functional groups which carry the 21- and 30-mu bands, and
molecules devoid of these but carrying strong phonon spectra. These results may
help understand the emergence of plateaus, the origin of continua underlying
FIR bands, as well as the composition of circumstellar dust.


title:
Pattern recognition techniques to reduce backgrounds in the search for
  the 136Xe double beta decay with gaseous TPCs

abstract:
  The observation of the neutrinoless double beta decay may provide essential
information on the nature of neutrinos. Among the current experimental
approaches, a high pressure gaseous TPC is an attractive option for the search
of double beta decay due to its good energy resolution and the detailed
topological information of each event. We present in this talk a detailed study
of the ionization topology of the 136Xe double beta decay events in a High
Pressure Xenon TPC, as well as that of the typical competing backgrounds. We
define some observables based on graph theory concepts to develop automated
discrimination algorithms. Our criteria are able to reduce the background level
by about three orders of magnitude in the region of interest of the 136Xe Qbb
for a signal acceptance of 40%. This result provides a quantitative assessment
of the benefit of topological information offered by gaseous TPCs for double
beta decay search, and proves that it is a promising feature in view of future
experiments in the field. Possible ideas for further improvement in the
discrimination algorithms and the dependency of these results with the gas
diffusion and readout granularity will be also discussed.


title:
Analytical Light Curve Models of Super-Luminous Supernovae:
  chi^2-Minimizations of Parameter Fits

abstract:
  We present fits of generalized semi-analytic supernova (SN) light curve (LC)
models for a variety of power inputs including Ni-56 and Co-56 radioactive
decay, magnetar spin-down, and forward and reverse shock heating due to
supernova ejecta-circumstellar matter (CSM) interaction. We apply our models to
the observed LCs of the H-rich Super Luminous Supernovae (SLSN-II) SN 2006gy,
SN 2006tf, SN 2008am, SN 2008es, CSS100217, the H-poor SLSN-I SN 2005ap,
SCP06F6, SN 2007bi, SN 2010gx and SN 2010kd as well as to the interacting SN
2008iy and PTF09uj. Our goal is to determine the dominant mechanism that powers
the LCs of these extraordinary events and the physical conditions involved in
each case. We also present a comparison of our semi-analytical results with
recent results from numerical radiation hydrodynamics calculations in the
particular case of SN 2006gy in order to explore the strengths and weaknesses
of our models. We find that CS shock heating produced by ejecta-CSM interaction
provides a better fit to the LCs of most of the events we examine. We discuss
the possibility that collision of supernova ejecta with hydrogen-deficient CSM
accounts for some of the hydrogen-deficient SLSNe (SLSN-I) and may be a
plausible explanation for the explosion mechanism of SN 2007bi, the
pair-instability supernova (PISN) candidate. We characterize and discuss issues
of parameter degeneracy.


title: Small deviations in lognormal Mandelbrot cascades

abstract:
  We study small deviations in Mandelbrot cascades and some related models.
Denoting by $Y$ the total mass variable of a Mandelbrot cascade generated by
$W$, we show that if $\log \log 1/P(W \leq x) \sim \gamma \log \log 1/x$ as $x
\to 0$ with $\gamma > 1$, then the Laplace transform of $Y$ satisfies $\log
\log 1/\E e^{-t Y} \sim \gamma \log \log t$ as $t \to \infty$. As an
application, this gives new estimates for $\Prob(Y \leq x)$ for small $x > 0$.
As another application of our methods, we prove a similar result for a variable
arising as a total mass of a lognormal $\star$-scale invariant multiplicative
chaos measure.


title: A general smoothing inequality for disordered polymers

abstract:
  This note sharpens the smoothing inequality of Giacomin and Toninelli for
disordered polymers. This inequality is shown to be valid for any disorder
distribution with locally finite exponential moments, and to provide an
asymptotically sharp constant for weak disorder. A key tool in the proof is an
estimate that compares the effect on the free energy of tilting, respectively,
shifting the disorder distribution. This estimate holds in large generality
(way beyond disordered polymers) and is of independent interest.


title: Energy Conditions in $f(R,T,R_{\mu\nu}T^{\mu\nu})$ Gravity

abstract:
  We discuss the validity of the energy conditions in a newly modified theory
named as $f(R,T,R_{\mu\nu}T^{\mu\nu})$ gravity, where $R$ and $T$ represent the
scalar curvature and trace of the energy-momentum tensor. The corresponding
energy conditions are derived which appear to be more general and can reduce to
the familiar forms of these conditions in general relativity, $f(R)$ and
$f(R,T)$ theories. The general inequalities are presented in terms of recent
values of Hubble, deceleration, jerk and snap parameters. In particular, we use
two specific models recently developed in literature to study concrete
application of these conditions as well as Dolgov-Kawasaki instability.
Finally, we explore $f(R,T)$ gravity as a specific case to this modified theory
for exponential and power law models.


title: Quantum Techniques for Reaction Networks

abstract:
  Reaction networks are a general formalism for describing collections of
classical entities interacting in a random way. While reaction networks are
mainly studied by chemists, they are equivalent to Petri nets, which are used
for similar purposes in computer science and biology. As noted by Doi and
others, techniques from quantum field theory can be adapted to apply to such
systems. Here we use these techniques to study how the "master equation"
describing stochastic time evolution for a reaction network is related to the
"rate equation" describing the deterministic evolution of the expected number
of particles of each species in the large-number limit. We show that the
relation is especially strong when a solution of master equation is a "coherent
state", meaning that the numbers of entities of each kind are described by
independent Poisson distributions.


title: Algorithms for Tolerant Tverberg Partitions

abstract:
  Let $P$ be a $d$-dimensional $n$-point set. A partition $T$ of $P$ is called
a Tverberg partition if the convex hulls of all sets in $T$ intersect in at
least one point. We say $T$ is $t$-tolerant if it remains a Tverberg partition
after deleting any $t$ points from $P$. Sober\'{o}n and Strausz proved that
there is always a $t$-tolerant Tverberg partition with $\lceil n / (d+1)(t+1)
\rceil$ sets. However, so far no nontrivial algorithms for computing or
approximating such partitions have been presented.
  For $d \leq 2$, we show that the Sober\'{o}n-Strausz bound can be improved,
and we show how the corresponding partitions can be found in polynomial time.
For $d \geq 3$, we give the first polynomial-time approximation algorithm by
presenting a reduction to the Tverberg problem with no tolerance. Finally, we
show that it is coNP-complete to determine whether a given Tverberg partition
is t-tolerant.


title: Interfacial Magnetism in Manganite Superlattices

abstract:
  We use a two-orbital double-exchange model including Jahn-Teller lattice
distortions, superexchange interactions, and long-range Coulomb (LRC)
interactions to investigate the origin of magnetically disordered interfaces
between ferromagnetic metallic (FM) and antiferromagnetic insulating (AFI)
manganites in FM/AFI superlattices. The induced magnetic moment in the AFI
layer varies non-monotonically with increasing AFI layer width as seen in the
experiment. We provide a framework for understanding this non-monotonic
behavior which has a one-to-one correspondence with the magnetization of the FM
interface. The obtained insights provide a basis for improving the tunneling
magnetoresistance in FM/AFI manganite superlattices by avoiding a magnetic dead
layer (MDL) in the FM manganite.


title: Vulnerability of robust preferential attachment networks

abstract:
  Scale-free networks with small power law exponent are known to be robust,
meaning that their qualitative topological structure cannot be altered by
random removal of even a large proportion of nodes. By contrast, it has been
argued in the science literature that such networks are highly vulnerable to a
targeted attack, and removing a small number of key nodes in the network will
dramatically change the topological structure. Here we analyse a class of
preferential attachment networks in the robust regime and prove four main
results supporting this claim: After removal of an arbitrarily small proportion
epsilon>0 of the oldest nodes (1) the asymptotic degree distribution has
exponential instead of power law tails; (2) the largest degree in the network
drops from being of the order of a power of the network size n to being just
logarithmic in n; (3) the typical distances in the network increase from order
log log n to order log n; and (4) the network becomes vulnerable to random
removal of nodes. Importantly, all our results explicitly quantify the
dependence on the proportion epsilon of removed vertices. For example, we show
that the critical proportion of nodes that have to be retained for survival of
the giant component undergoes a steep increase as epsilon moves away from zero,
and a comparison of this result with similar ones for other networks reveals
the existence of two different universality classes of robust network models.
The key technique in our proofs is a local approximation of the network by a
branching random walk with two killing boundaries, and an understanding of the
particle genealogies in this process, which enters into estimates for the
spectral radius of an associated operator.


title: An Appraisal of Muon Neutrino Disappearance at Short Baseline

abstract:
  Neutrino physics is nowadays receiving more and more attention as a possible
source of information for the long standing problem of new Physics beyond the
Standard Model. The recent measurements of the third mixing angle $\theta_{13}$
in the standard mixing oscillation scenario encourage to pursue the still
missing results on the leptonic CP violation and the absolute neutrino masses.
However, several puzzling and incomplete measurements are in place which
deserve an exhaustive evaluation and study. We will report about the present
situation of the muon disappearance measurements at small $L/E$ in the context
of the current CERN project to revitalize the neutrino field in Europe and the
search for sterile neutrinos. We will then illustrate the achievements that a
double muon spectrometer can attain in terms of discovery of new neutrino
states, performing a newly developed analysis.


title: EFSMT: A Logical Framework for Cyber-Physical Systems

abstract:
  The design of cyber-physical systems is challenging in that it includes the
analysis and synthesis of distributed and embedded real-time systems for
controlling, often in a nonlinear way, the environment. We address this
challenge with EFSMT, the exists-forall quantified first-order fragment of
propositional combinations over constraints (including nonlinear arithmetic),
as the logical framework and foundation for analyzing and synthesizing
cyber-physical systems. We demonstrate the expressiveness of EFSMT by reducing
a number of pivotal verification and synthesis problems to EFSMT. Exemplary
problems in this paper include synthesis for robust control via BIBO stability,
Lyapunov coefficient finding for nonlinear control systems, distributed
priority synthesis for orchestrating system components, and synthesis for
hybrid control systems. We are also proposing an algorithm for solving EFSMT
problems based on the interplay between two SMT solvers for respectively
solving universally and existentially quantified problems. This algorithms
builds on commonly used techniques in modern SMT solvers, and generalizes them
to quantifier reasoning by counterexample-guided constraint strengthening. The
EFSMT solver uses Bernstein polynomials for solving nonlinear arithmetic
constraints.


title:
A NLTE analysis of the hot subdwarf O star Bd+28 4211. I. The UV
  spectrum

abstract:
  We present a detailed analysis of the UV spectrum of the calibration star
Bd+28 4211 using high-quality spectra obtained with the HST and FUSE
satellites. To this aim, we compare quantitatively the observed data with model
spectra obtained from state-of-the-art NLTE metal line-blanketed model
atmospheres and synthetic spectra calculated with TLUSTY and SYNSPEC. We thus
determine in a self-consistent way the abundances of eleven elements with
well-defined lines in the UV, namely those of C, N, O, F, Mg, Si, P, S, Ar, Fe,
and Ni. The derived abundances range from about solar to 1/10 solar. We find
that the overall quality of the derived spectral fits is very satisfying. Our
spectral analysis can be used to constrain rather tigthly the effective
temperature of Bd+28 to a value of teff = 82,000 +/- 5000 K. We also estimate
conservatively that its surface gravity falls in the range log g = 6.2
-0.1/+0.3. Assuming that the Hipparcos measurement for Bd+28 is fully reliable
and that our model atmospheres are reasonably realistic, we can reconcile our
spectroscopic constraints with the available parallax measurement only if the
mass of Bd+28 is significantly less than the canonical value of 0.5 msun for a
representative post-EHB star.


title: Dynamics of apparent horizons in quantum gravitational collapse

abstract:
  We study the gravitational collapse of a massless scalar field within the
effective scenario of loop quantum gravity. Classical singularity is avoided
and replaced by a quantum bounce in this model. It is shown that, quantum
gravity effects predict a threshold scale below which no horizon can form as
the collapse evolves towards the bounce.


title:
Eigenvalue counting inequalities, with applications to Schrodinger
  operators

abstract:
  We derive a sufficient condition for a Hermitian $N \times N$ matrix $A$ to
have at least $m$ eigenvalues (counting multiplicities) in the interval
$(-\epsilon, \epsilon)$. This condition is expressed in terms of the existence
of a principal $(N-2m) \times (N-2m)$ submatrix of $A$ whose Schur complement
in $A$ has at least $m$ eigenvalues in the interval $(-K\epsilon, K\epsilon)$,
with an explicit constant $K$.
  We apply this result to a random Schrodinger operator $H_\omega$, obtaining a
criterion that allows us to control the probability of having $m$ closely lying
eigenvalues for $H_\omega$-a result known as an $m$-level Wegner estimate. We
demonstrate its usefulness by verifying the input condition of our criterion
for some physical models. These include the Anderson model and random block
operators that arise in the Bogoliubov-de Gennes theory of dirty
superconductors.


title:
RDCI: A novel method of cluster analysis and applications thereof in
  sample molecular simulations

abstract:
  A novel method, termed Reduced Dimensionality Cluster Identification, RDCI,
is presented, for the identification and quantitative description of clusters
formed by N objects in three dimensional space. The method consists of finding
a path, as short as possible, connecting the objects, and then tracking down
the size s, of a subgroup i-n, i-n+1, ..., i+n, of 2n+1 < N particles for i
varying from n+1 to N-n. Clusters are located where local minima of s(i) occur
whereas local maxima serve as delimiters partitioning the path in subsets
containing the clusters. Minimal post-processing allows for the removal of
outliers on the basis of user-defined criteria and the identification of
clearly defined clusters. The advantage of the method is that it requires no
predetermined input or criteria of "clusterness" such as number of objects or
size of aggregates. Among the numerous possible applications of the method,
results are herein reported, from Molecular Dynamics simulations of a binary
mixture of Lennard-Jones fluids and of a model polymeric system with a gas-like
substance dispersed in it. The method is shown to allow the extraction of
meaningful quantitative information regarding the tendency of molecules to
cluster or de-cluster and the dynamics of the clustering processes.


title: Laser cooling of rotation and vibration by optical pumping

abstract:
  We have recently demonstrated that optical pumping methods combined with
photoassociation of ultra-cold atoms can produce ultra-cold and dense samples
of molecules in their absolute rovibronic ground state. More generally, both
the external and internal degrees of freedom can be cooled by addressing
selected rovibrational levels on demand. Here, we recall the basic concepts and
main steps of our experiments, including the excitation schemes and detection
techniques we use to achieve the rovibrational cooling of Cs2 molecules. In
addition, we present the determination of formation pathways and a theoretical
analysis explaining the experimental observations. These simulations improves
the spectroscopic knowledge required to transfer molecules to any desired
rovibrational level.


title:
Time- and Space-Modulated Raman Signals in Graphene-based Optical
  Cavities

abstract:
  We present fabrication and optical characterization of micro-cavities made of
multilayer graphene (MLG) cantilevers clamped by metallic electrodes and
suspended over Si/Si02 substrate. Graphene cantilevers act as a
semi-transparent mirrors closing an air-wedge optical cavity. This simple
geometry implements a standing-wave optical resonator along with a mechanical
one. Equal thickness interference fringes are observed in both Raman and
Rayleigh backscattered signals with interfringe given by their specific
wavelength.Chromatic dispersion within the cavity makes possible spatial
modulation of graphene Raman lines and selective rejection of the silicon
background signals. Electrostatic actuation of the multilayer graphene
cantilever by gate voltage tunes the cavity length and induces space and time
modulation of backscattered light including Raman lines. We demonstrate the
potential of those systems for high sensitivity Raman measurements of generic
molecular species grafted on multilayer graphene surface. The Raman signal of
the molecular layer can be modulated both in time and in space in a similar
fashion and show enhancement with respect to a collapsed membrane.


title: A momentum filter for atomic gas

abstract:
  We propose and demonstrate a momentum filter for atomic gas based on a
designed Talbot-Lau interferometer. It consists in two identical optical
standing wave pulses separated by a delay equal to odd multiples of the half
Talbot time. The one dimensional momentum width along the long direction of a
cigar shape condensate is rapidly and greatly purified to a minimum, which
corresponds to the ground state energy of the confining trap in our experiment.
We find good agreement between theoretical analysis and experimental results.
The filter is also effective for non-condensed cold atoms and could be applied
widely.


title:
Unified formal reduction for fluid models of free-surface shallow
  gravity-flows

abstract:
  We propose a unified approach to the formal long-wave reduction of several
fluid models for thin-layer incompressible homogeneous flows driven by a
constant external force like gravity. The procedure is based on a mathematical
coherence property that univoquely defines one reduced model given one rheology
and one thin-layer regime. For the first time, as far as we know, various known
reduced models can thus be investigated within a single mathematical framework,
for various rheologies (viscous and viscoelastic) and various limit regimes
(fast inertial flows and slow viscous flows). Furthermore, our systematic
procedure also produces new reduced models for viscoelastic non-Newtonian
fluids and improves on our previous work [Bouchut & Boyaval, M3AS (23) 8,
2013].


title: Dynamics of a producer-parasite ecosystem on the brink of collapse

abstract:
  Ecosystems can undergo sudden shifts to undesirable states, but recent
studies with simple single species ecosystems have demonstrated that advance
warning can be provided by the slowing down of population dynamics near a
tipping point. However, it is not clear how this effect of critical slowing
down will manifest in ecosystems with strong interactions between their
components. Here we probe the dynamics of an experimental producer parasite
ecosystem as it approaches a catastrophic collapse. Surprisingly, the producer
population grows in size as the environment deteriorates, highlighting that
population size can be a misleading measure of ecosystem stability. By
analyzing the oscillatory producer parasite dynamics for over ~100 generations
in multiple environmental conditions, we found that the collective ecosystem
dynamics slows down as the tipping point is approached. Analysis of the coupled
dynamics of interacting populations may therefore be necessary to provide
advance warning of collapse in complex communities.


title:
Sashimi plots: Quantitative visualization of RNA sequencing read
  alignments

abstract:
  We introduce Sashimi plots, a quantitative multi-sample visualization of mRNA
sequencing reads aligned to gene annotations. Sashimi plots are made using
alignments (stored in the SAM/BAM format) and gene model annotations (in GFF
format), which can be custom-made by the user or obtained from databases such
as Ensembl or UCSC. We describe two implementations of Sashimi plots: (1) a
stand-alone command line implementation aimed at making customizable
publication quality figures, and (2) an implementation built into the
Integrated Genome Viewer (IGV) browser, which enables rapid and dynamic
creation of Sashimi plots for any genomic region of interest, suitable for
exploratory analysis of alternatively spliced regions of the transcriptome.
Isoform expression estimates outputted by the MISO program can be optionally
plotted along with Sashimi plots. Sashimi plots can be used to quickly screen
differentially spliced exons along genomic regions of interest and can be used
in publication quality figures. The Sashimi plot software and documentation is
available from: http://genes.mit.edu/burgelab/miso/docs/sashimi.html


title:
GRB 090510: a disguised short GRB with the highest Lorentz factor and
  circumburst medium

abstract:
  GRB 090510, observed both by Fermi and AGILE satellites, is the first bright
short-hard Gamma-Ray Burst (GRB) with an emission from the keV up to the GeV
energy range. Within the Fireshell model, we interpret the faint precursor in
the light curve as the emission at the transparency of the expanding e+e-
plasma: the Proper-GRB (P-GRB). From the observed isotropic energy we assume a
total energy Ee+e-=(1.10+-0.06)*10^53 erg and derive a Baryon load
B=(1.45+-0.28)*10^(-3) and a Lorentz factor at transparency
Gamma=(6.7+-1.6)*10^2. The main emission 0.4 s after the initial spike is
interpreted as the extended afterglow, due to the interaction of the
ultrarelativistic baryons with the CircumBurst Medium (CBM). Using the
condition of fully radiative regime, we infer a CBM average spherically
symmetric density of nCBM=(1.85+-0.14)10^3 cm^(-3), one of the highest found in
the Fireshell model. The value of the filling factor,
1.5*10^(-10)<R<3.8*10^(-8), leads to the estimate of filaments with densities
nfil=nCBM/R=(10^6 - 10^14) cm^(-3). The sub-MeV and the MeV emissions are well
reproduced. When compared to the canonical GRBs with nCBM=1 cm^(-3) and to the
disguised short GRBs with nCBM=10^(-3) cm^(-3), the case of GRB 090510 leads to
the existence of a new family of bursts exploding in an over-dense galactic
region with hn nCBM=10^3 cm^(-3). The joint effect of the high Lorentz factor
and the high density compresses in time and "inflates" in intensity the
extended afterglow, making it appear as a short burst, which we here define as
"disguised short GRB by excess". The determination of the above parameters
values may represent an important step towards the explanation of the GeV
emission.


abstract:
  Degeneracy effects for bosons are more important for smaller particle mass,
smaller temperature and higher number density. Bose condensation requires that
particles be in the same lowest energy quantum state. We propose a cosmic
background Bose condensation, present everywhere, whith its particles having
the lowest quantum energy state, $\hbar c / \lambda$, with $\lambda$ about the
size of the visible universe, and therefore unlocalized. This we identify with
the quantum of the self gravitational potential energy of any particle, and
with the bit of information of minimum energy. The entropy of the universe
($\sim 10^{122} \ bits$) has the highest number density ($ \sim 10^{36} \ bits
/ cm^3$) of particles inside the visible universe, the smallest mass, $\sim
10^{-66} g$, and the smallest temperature, $\sim 10^{-29} K$. Therefore it is
the best candidate for a Cosmic Background Bose Condensation (CBBC), a
completely calmed fluid, with no viscosity, in a superfluidity state, and
possibly responsible for the expansion of the universe.


title: All automorphisms of the universal sofic group are class-preserving

abstract:
  In this article we prove that every automorphism of a universal sofic group
is class preserving, i.e. preserves the conjugacy classes


title:
Extragalactic millimeter-wave point source catalog, number counts and
  statistics from 771 square degrees of the SPT-SZ Survey

abstract:
  We present a point source catalog from 771 square degrees of the South Pole
Telescope Sunyaev Zel'dovich (SPT-SZ) survey at 95, 150, and 220 GHz. We detect
1545 sources above 4.5 sigma significance in at least one band. Based on their
relative brightness between survey bands, we classify the sources into two
populations, one dominated by synchrotron emission from active galactic nuclei,
and one dominated by thermal emission from dust-enshrouded star-forming
galaxies. We find 1238 synchrotron and 307 dusty sources. We cross-match all
sources against external catalogs and find 189 unidentified synchrotron sources
and 189 unidentified dusty sources. The dusty sources without counterparts are
good candidates for high-redshift, strongly lensed submillimeter galaxies. We
derive number counts for each population from 1 Jy down to roughly 9, 5, and 11
mJy at 95, 150, and 220 GHz. We compare these counts with galaxy population
models and find that none of the models we consider for either population
provide a good fit to the measured counts in all three bands. The disparities
imply that these measurements will be an important input to the next generation
of millimeter-wave extragalactic source population models.


title: The Starobinsky Model from Superconformal D-Term Inflation

abstract:
  We point out that in the large field regime, the recently proposed
superconformal D-term inflation model coincides with the Starobinsky model. In
this regime, the inflaton field dominates over the Planck mass in the
gravitational kinetic term in the Jordan frame. Slow-roll inflation is realized
in the large field regime for sufficiently large gauge couplings. The
Starobinsky model generally emerges as an effective description of slow-roll
inflation if a Jordan frame exists where, for large inflaton field values, the
action is scale invariant and the ratio \hat {\lambda} of the inflaton
self-coupling and the nonminimal coupling to gravity is tiny. The
interpretation of this effective coupling is different in different models. In
superconformal D-term inflation it is determined by the scale of grand
unification, \hat {\lambda} ~ (\Lambda_{GUT}/M_P)^4.


title: Zero-field Quantum Critical Point in CeCoIn$_5$

abstract:
  Quantum criticality in the normal and superconducting state of the
heavy-fermion metal CeCoIn$_5$ is studied by measurements of the magnetic
Gr\"{u}neisen ratio, $\Gamma_H$, and specific heat in different field
orientations and temperatures down to 50 mK. Universal temperature over
magnetic field scaling of $\Gamma_H$ in the normal state indicates a hidden
quantum critical point at zero field. Within the superconducting state the
quasiparticle entropy at constant temperature increases upon reducing the field
towards zero, providing additional evidence for zero-field quantum criticality.


title: On the dynamics and thermodynamics of terrestrial planets

abstract:
  A model for terrestrial planets, inclusive of viscous fluid behavior and
featuring finite normal stress differences, is developed. This work offers new
insights for the interpretation of planetary survey data. Evolution equations
for poloidal and toroidal motions include gradients of density, viscosity, and
two normal stress moduli. The poloidal field exhibits gradients in the cubic
dilation, which couple non-isotropic pressures to the combined deformation
field. In contrast, the toroidal field exhibits vorticity gradients with
magnitudes proportional to the natural time. This holds even in the absence of
material gradients. Consequently, viscosity gradients are not required to drive
toroidal motions. The toroidal field is governed by an inhomogeneous diharmonic
equation, exhibiting dynamic shear localization. The strain-energy density for
this model, as a function of temperature, is found via thermodynamics. Assuming
heat transfer with characteristic diffusivity, a radial model parameterized by
thermomechanical competence is found. Shear dislocations, admissible for
thermomechanical competence greater than 1/2, are found to coincide with
supershear rupture speeds for in-plane (Mode II) cracks. This range of
thermomechanical competence coincides with depths in the crust, upper mantle
and transition zone where earthquake foci are observed. Consequently, all
seismic sources must exhibit some supershearing component. Observed variations
in Earth's gravity-topography admittance and correlation spectra, and
earthquake moment-depth release are interpreted in light of this hypothetical
structure.


title:
Classifying Single-Trial EEG during Motor Imagery with a Small Training
  Set

abstract:
  Before the operation of a motor imagery based brain-computer interface (BCI)
adopting machine learning techniques, a cumbersome training procedure is
unavoidable. The development of a practical BCI posed the challenge of
classifying single-trial EEG with a small training set. In this letter, we
addressed this problem by employing a series of signal processing and machine
learning approaches to alleviate overfitting and obtained test accuracy similar
to training accuracy on the datasets from BCI Competition III and our own
experiments.


title: Remote Oscillatory responses to a solar flare

abstract:
  The processes governing energy storage and release in the Sun are both
related to the solar magnetic field. We demonstrate the existence of a magnetic
connection between energy released caused by a flare and increased oscillatory
power in the lower solar atmosphere. The oscillatory power in active regions
tends to increase in response to explosive events at a different location, but
not in the region itself. We carry out timing studies and show that this is
probably caused by a large scale magnetic connection between the regions, and
not a globally propagating wave. We show that oscillations tend to exist in
longer lived wave trains at short periods (P< 200s) at the time of a flare.
This may be a mechanism by which flare energy can be redistributed throughout
the solar atmosphere.


title:
Hyperparameter Optimization and Boosting for Classifying Facial
  Expressions: How good can a "Null" Model be?

abstract:
  One of the goals of the ICML workshop on representation and learning is to
establish benchmark scores for a new data set of labeled facial expressions.
This paper presents the performance of a "Null" model consisting of
convolutions with random weights, PCA, pooling, normalization, and a linear
readout. Our approach focused on hyperparameter optimization rather than novel
model components. On the Facial Expression Recognition Challenge held by the
Kaggle website, our hyperparameter optimization approach achieved a score of
60% accuracy on the test data. This paper also introduces a new ensemble
construction variant that combines hyperparameter optimization with the
construction of ensembles. This algorithm constructed an ensemble of four
models that scored 65.5% accuracy. These scores rank 12th and 5th respectively
among the 56 challenge participants. It is worth noting that our approach was
developed prior to the release of the data set, and applied without
modification; our strong competition performance suggests that the TPE
hyperparameter optimization algorithm and domain expertise encoded in our Null
model can generalize to new image classification data sets.


title:
Type II hidden symmetries for the homogeneous heat equation in some
  general classes of Riemannian spaces

abstract:
  We study the reduction of the heat equation in Riemannian spaces which admit
a gradient Killing vector, a gradient homothetic vector and in Petrov Type
D,N,II and Type III space-times. In each reduction we identify the source of
the Type II hidden symmetries. More specifically we find that a) If we reduce
the heat equation by the symmetries generated by the gradient KV the reduced
equation is a linear heat equation in the nondecomposable space. b) If we
reduce the heat equation via the symmetries generated by the gradient HV the
reduced equation is a Laplace equation for an appropriate metric. In this case
the Type II hidden symmetries are generated from the proper CKVs. c) In the
Petrov spacetimes the reduction of the heat equation by the symmetry generated
from the nongradient HV gives PDEs which inherit the Lie symmetries hence no
Type II hidden symmetries appear. We apply the general results to cases in
which the initial metric is specified. We consider the case that the
irreducible part of the decomposed space is a space of constant nonvanishing
curvature and the case of the spatially flat Friedmann-Robertson-Walker space
time used in Cosmology. In each case we give explicitly the Type II hidden
symmetries provided they exist.


title: Symplectic spreads, planar functions and mutually unbiased bases

abstract:
  In this paper we give explicit descriptions of complete sets of mutually
unbiased bases (MUBs) and orthogonal decompositions of special Lie algebras
$sl_n(\mathbb{C})$ obtained from commutative and symplectic semifields, and
from some other non-semifield symplectic spreads. Relations between various
constructions are also studied. We show that the automorphism group of a
complete set of MUBs is isomorphic to the automorphism group of the
corresponding orthogonal decomposition of the Lie algebra $sl_n(\mathbb{C})$.
In the case of symplectic spreads this automorphism group is determined by the
automorphism group of the spread. By using the new notion of pseudo-planar
functions over fields of characteristic two we give new explicit constructions
of complete sets of MUBs.


title:
Ruin probability of a discrete-time risk process with proportional
  reinsurance and investment for exponential and Pareto distributions

abstract:
  In this paper a quantitative analysis of the ruin probability in finite time
of discrete risk process with proportional reinsurance and investment of
finance surplus is focused on. It is assumed that the total loss on a unit
interval has a light-tailed distribution -- exponential distribution and a
heavy-tailed distribution -- Pareto distribution. The ruin probability for
finite-horizon 5 and 10 was determined from recurrence equations. Moreover for
exponential distribution the upper bound of ruin probability by Lundberg
adjustment coefficient is given. For Pareto distribution the adjustment
coefficient does not exist, hence an asymptotic approximation of the ruin
probability if an initial capital tends to infinity is given. Obtained
numerical results are given as tables and they are illustrated as graphs.


title: A Faster Algorithm for Packing Branchings in Digraphs

abstract:
  We consider the problem of finding an integral packing of branchings in a
capacitated digraph with root-set demands. Schrijver described an algorithm
that returns a packing with at most m+n^3+r branchings that makes at most
m(m+n^3+r) calls to an oracle that basically computes a minimum cut, where n is
the number of vertices, m is the number of arcs and r is the number of
root-sets of the input digraph. In this work we provide an algorithm, inspired
on ideas of Schrijver and on an paper of Gabow and Manu, that returns a packing
with at most m+r-1 branchings and makes at most 2n+m+r-1 oracle calls.


title: Visualizing Astronomical Data with Blender

abstract:
  Astronomical data take on a multitude of forms -- catalogs, data cubes,
images, and simulations. The availability of software for rendering
high-quality three-dimensional graphics lends itself to the paradigm of
exploring the incredible parameter space afforded by the astronomical sciences.
The software program Blender gives astronomers a useful tool for displaying
data in a manner used by three-dimensional (3D) graphics specialists and
animators. The interface to this popular software package is introduced with
attention to features of interest in astronomy. An overview of the steps for
generating models, textures, animations, camera work, and renders is outlined.
An introduction is presented on the methodology for producing animations and
graphics with a variety of astronomical data. Examples from sub-fields of
astronomy with different kinds of data are shown with resources provided to
members of the astronomical community. An example video showcasing the outlined
principles and features is provided along with scripts and files for sample
visualizations.


title: Set-Difference Range Queries

abstract:
  We introduce the problem of performing set-difference range queries, where
answers to queries are set-theoretic symmetric differences between sets of
items in two geometric ranges. We describe a general framework for answering
such queries based on a novel use of data-streaming sketches we call signed
symmetric-difference sketches. We show that such sketches can be realized using
invertible Bloom filters (IBFs), which can be composed, differenced, and
searched so as to solve set-difference range queries in a wide range of
scenarios.


title:
On the realization problem of plane real algebraic curves as Hessian
  curves

abstract:
  The Hessian Topology is a subject having interesting relations with several
areas, for instance, differential geometry, implicit differential equations,
analysis and singularity theory. In this article we study the problem of
realization of a real plane curve as the Hessian curve of a smooth function.
The plane curves we consider are constituted either by only outer ovals or
inner ovals. We prove that some of such curves are realizable as Hessian
curves.


title:
An Information Theoretic Study of Timing Side Channels in Two-user
  Schedulers

abstract:
  Timing side channels in two-user schedulers are studied. When two users share
a scheduler, one user may learn the other user's behavior from patterns of
service timings. We measure the information leakage of the resulting timing
side channel in schedulers serving a legitimate user and a malicious attacker,
using a privacy metric defined as the Shannon equivocation of the user's job
density. We show that the commonly used first-come-first-serve (FCFS) scheduler
provides no privacy as the attacker is able to to learn the user's job pattern
completely. Furthermore, we introduce an scheduling policy,
accumulate-and-serve scheduler, which services jobs from the user and attacker
in batches after buffering them. The information leakage in this scheduler is
mitigated at the price of service delays, and the maximum privacy is achievable
when large delays are added.


title: Suspended Long-Lived NMR Echo in Solids

abstract:
  We report an observation of extremely long-lived spin states in systems of
dipolar-coupled nuclear spins in solids. The 'suspended echo' experiment uses a
simple stimulated echo pulse sequence and creates non-equilibrium states which
live many orders of magnitude longer than the characteristic time of spin-spin
dynamics T2. Large amounts of information can be encoded in such long-lived
states, stored in a form of multi-spin correlations, and subsequently retrieved
by an application of a single 'reading' pulse.


title: Masses of the Bottom-Charm Hybrid $\bar bGc$ States

abstract:
  QCD sum rules are used to study the mass spectrum of bottom-charm hybrid
$\bar bGc$ systems. The correlation functions and the spectral densities are
calculated up to dimension six condensates at leading order of $\alpha_s$ for
several $J^P$ quantum numbers. After performing the QCD sum rule analysis, we
predict the masses of the $J^P=0^{-}, 0^{+}, 1^{-}, 1^{+}, 2^{-}, 2^{+}$
bottom-charm hybrids. These mass predictions show a similar supermultiplet
structure as the bottomonium and charmonium hybrids. Using the QCD sum-rule
mass predictions we analyze the possible hadronic decay patterns of the $\bar
cGc$, $\bar bGc$ and $\bar bGb$ hybrids including the open-flavour and
hidden-flavour mechanisms.


title: Twisted Alexander invariants detect trivial links

abstract:
  It follows from earlier work of Silver-Williams and the authors that twisted
Alexander polynomials detect the unknot and the Hopf link. We now show that
twisted Alexander polynomials also detect the trefoil and the figure-8 knot,
that twisted Alexander polynomials detect whether a link is split and that
twisted Alexander modules detect trivial links.


title: Non-global parameter estimation using local ensemble Kalman filtering

abstract:
  We study parameter estimation for non-global parameters in a low-dimensional
chaotic model using the local ensemble transform Kalman filter (LETKF). By
modifying existing techniques for using observational data to estimate global
parameters, we present a methodology whereby spatially-varying parameters can
be estimated using observations only within a localized region of space. Taking
a low-dimensional nonlinear chaotic conceptual model for atmospheric dynamics
as our numerical testbed, we show that this parameter estimation methodology
accurately estimates parameters which vary in both space and time, as well as
parameters representing physics absent from the model.


title:
High Capacity Quantum Key Distribution via Hyper-Entangled Degrees of
  Freedom

abstract:
  Quantum key distribution (QKD) has long been a promising area for application
of quantum effects toward solving real-world problems. But two major obstacles
have stood in the way of widespread applications: low secure key generation
rates and short achievable operating distances. In this paper, a new physical
mechanism for dealing with the first of these problems is proposed: interplay
between different degrees of freedom in a hyperentangled system (parametric
down conversion) is used to increase the Hilbert space dimension available for
key generation while maintaining security. Polarization-based Bell tests
provide security checking, while orbital angular momentum (OAM) and total
angular momentum (TAM) provide higher key generation rate. Whether to measure
TAM or OAM is decided randomly on each trial. The concurrent non-commutativity
of TAM with OAM and polarization provides the physical basis for quantum
security. TAM measurements link polarization to OAM, so that if the legitimate
participants measure OAM while the eavesdropper measures TAM (or vice-versa),
then polarization entanglement is lost, revealing the eavesdropper. In contrast
to other OAM-based QKD methods, complex active switching between OAM bases is
not required; instead, passive switching by beam splitters combined with much
simpler active switching between polarization bases makes implementation at
high OAM more practical.


title:
Can Rossby waves explain the cyclic magnetic activity of the Sun and
  solar-type stars?

abstract:
  Magnetic activity is a global property of the Sun; the complex processes of
solar activity are connected with the solar magnetic fields. For solar-type
stars and the Sun magnetic activity depends on the physical parameters of the
star. In this article we study the relationships between the duration of
activity cycle and effective temperature for solar-type stars and the Sun.
We've tried to explain these relationships due to the existence of layer of
laminar convection near the bottom of the convective zone of the star. In this
layer the Rossby waves are formed. They generate the primary poloidal magnetic
field, which is the source of energy of the complex phenomena of magnetic
activity.


title:
Distinct dynamical and structural properties of a core-softened fluid
  when confined between fluctuating and fixed walls

abstract:
  We study the influence of mobility of the confining media in the structural
and dynamical properties of a core-softened fluid under confinement. The fluid
is modeled using a two-length scale potential, which reproduces in bulk the
anomalous behavior observed in water. We perform simulations in the $NVT$
ensemble with fixed flat walls and in the $NpT$ ensemble using a fluctuating
wall control of pressure to study how the fluid behavior is affected by fixed
and non-fixed walls. Our results indicate that the fluid dynamical and
structural properties are strongly affected by the wall mobility. The distinct
observed behavior are explained in the framework of the two length scale
potential.


title: Syntactic Complexity of Circular Semi-Flower Automata

abstract:
  We investigate the syntactic complexity of certain types of finitely
generated submonoids of a free monoid. In fact, we consider those submonoids
which are accepted by circular semi-flower automata (CSFA). Here, we show that
the syntactic complexity of CSFA with at most one `branch point going in' (bpi)
is linear. Further, we prove that the syntactic complexity of $n$-state CSFA
with two bpis over a binary alphabet is $2n(n+1)$.


title:
A Heavy Ion Fireball freeze-out Dipion Cocktail for Au-Au Collisions at
  $\sqrt{s_{NN}}$=200 GeV $p_t$ dependence(Part 2)

abstract:
  In this paper we use methods developed in Part 1 of The Dipion Cocktail, to
fit the $p_t$ dependence of dipions for mid-central Au-Au collisions at
$\sqrt{s_{NN}}$=200 GeV. For the minijet fragmentation part we use PYTHIA
fragmentation as described in Part 1. For the thermal resonance production we
use an exponential growth behavior. The interference between the direct
production of dipion pairs from non-resonance minijet fragmentation and
re-scattering through resonance states gives a measure of the size of the
re-scattering region. This size is contain in the $\alpha$ parameter of Part1.
We assumed a relationship between the $\alpha$ parameter and the mass shift of
the $\rho$ resonance. The data used for the fits comes from the RHIC collider
as measured in the STAR experiment.


title:
Randomized maximum-contrast selection: subagging for large-scale
  regression

abstract:
  We introduce a very general method for sparse and large-scale variable
selection. The large-scale regression settings is such that both the number of
parameters and the number of samples are extremely large. The proposed method
is based on careful combination of penalized estimators, each applied to a
random projection of the sample space into a low-dimensional space. In one
special case that we study in detail, the random projections are divided into
non-overlapping blocks; each consisting of only a small portion of the original
data. Within each block we select the projection yielding the smallest
out-of-sample error. Our random ensemble estimator then aggregates the results
according to new maximal-contrast voting scheme to determine the final selected
set. Our theoretical results illuminate the effect on performance of increasing
the number of non-overlapping blocks. Moreover, we demonstrate that statistical
optimality is retained along with the computational speedup. The proposed
method achieves minimax rates for approximate recovery over all estimators
using the full set of samples. Furthermore, our theoretical results allow the
number of subsamples to grow with the subsample size and do not require
irrepresentable condition. The estimator is also compared empirically with
several other popular high-dimensional estimators via an extensive simulation
study, which reveals its excellent finite-sample performance.


title: Strongly primitive species with potentials I: Mutations

abstract:
  Motivated by the mutation theory of quivers with potentials developed by
Derksen-Weyman-Zelevinsky, and the representation-theoretic approach to cluster
algebras it provides, we propose a mutation theory of species with potentials
for species that arise from skew-symmetrizable matrices that admit a
skew-symmetrizer with pairwise coprime diagonal entries. The class of
skew-symmetrizable matrices covered by the mutation theory proposed here
contains a class of matrices that do not admit global unfoldings, that is,
unfoldings compatible with all possible sequences of mutations.


title: Weak local-global compatibility and ordinary representations

abstract:
  We introduce a general formalism with minimal requirements under which we are
able to prove the pro-modular Fontaine-Mazur conjecture. We verify it in the
ordinary case using the recent construction of Breuil and Herzig.


title: The number of vertices of a tropical curve is bounded by its area

abstract:
  We introduce the notion of tropical area of a tropical curve defined in an
open subset of $\mathbb R^n$. We prove that the number of vertices of a
tropical curve is bounded by the area of the curve. The approach is totally
elementary yet tricky. Our proof employs ideas from intersection theory in
algebraic geometry. The result can be interpreted as the fact that the moduli
space of tropical curves with bounded area is of finite type.


title:
Coincidence and Common Fixed Point Results for Generalized
  $\alpha$-$\psi$ Contractive Type Mappings with Applications

abstract:
  A new, simple and unified approach in the theory of contractive mappings was
recently given by Samet \emph{et al.} (Nonlinear Anal. 75, 2012, 2154-2165) by
using the concepts of $\alpha$-$\psi$-contractive type mappings and
$\alpha$-admissible mappings in metric spaces. The purpose of this paper is to
present a new class of contractive pair of mappings called generalized
$\alpha$-$\psi$ contractive pair of mappings and study various fixed point
theorems for such mappings in complete metric spaces. For this, we introduce a
new notion of $\alpha$-admissible w.r.t $g$ mapping which in turn generalizes
the concept of $g$-monotone mapping recently introduced by
$\acute{C}$iri$\acute{c}$ et al. (Fixed Point Theory Appl. 2008(2008), Article
ID 131294, 11 pages). As an application of our main results, we further
establish common fixed point theorems for metric spaces endowed with a partial
order as well as in respect of cyclic contractive mappings. The presented
theorems extend and subsumes various known comparable results from the current
literature. Some illustrative examples are provided to demonstrate the main
results and to show the genuineness of our results.


title:
Coherent States, Superpositions of Coherent States and Uncertainty
  Relations on a M\"obius Strip

abstract:
  Since symmetry properties of coherent states (CS) on M\"obius strip (MS) and
fermions are closely related, CS on MS are naturally associated to the
topological properties of fermionic fields. Here we consider CS and
superpositions of coherent states (SCS) on MS. We extend a recent propose of CS
on MS (Cirilo-Lombardo, 2012 [25]), including the analysis of periodic
behaviors of CS and SCS on MS and the uncertainty relations associated to
angular momentum and the phase angle. The advantage of CS and SCS on MS with
respect to the standard ones and potential applications in continuous variable
quantum computation are also addressed.

categories: quant-ph cond-mat.str-el hep-th math-ph math.MP


title:
Weak Hard X-ray Emission from Two Broad Absorption Line Quasars Observed
  with NuSTAR: Compton-thick Absorption or Intrinsic X-ray Weakness?

abstract:
  We present NuSTAR hard X-ray observations of two X-ray weak broad absorption
line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet).
Many BAL quasars appear X-ray weak, probably due to absorption by the shielding
gas between the nucleus and the accretion-disk wind. The two targets are among
the optically brightest BAL quasars, yet they are known to be significantly
X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars).
We would expect to obtain ~400-600 hard X-ray (>10 keV) photons with NuSTAR,
provided that these photons are not significantly absorbed (NH<1E24 cm^{-2}).
However, both BAL quasars are only detected in the softer NuSTAR bands (e.g.,
4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either
the shielding gas is highly Compton-thick or the two targets are intrinsically
X-ray weak. We constrain the column densities for both to be NH~7E24 cm^{-2} if
the weak hard X-ray emission is caused by obscuration from the shielding gas.
We discuss a few possibilities for how PG 1004+130 could have Compton-thick
shielding gas without strong Fe K? line emission; dilution from jet-linked
X-ray emission is one likely explanation. We also discuss the intrinsic X-ray
weakness scenario based on a coronal-quenching model relevant to the shielding
gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a
Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample
and place statistical constraints upon the fraction of intrinsically X-ray weak
BAL quasars; this fraction is likely 17-40%.


title: Matter inflation with A_4 flavour symmetry breaking

abstract:
  We discuss model building in tribrid inflation, which is a framework for
realising inflation in the matter sector of supersymmetric particle physics
models. The inflaton is a D-flat combination of matter fields, and inflation
ends by a phase transition in which some Higgs field obtains a vacuum
expectation value. We first describe the general procedure for implementing
tribrid inflation in realistic models of particle physics that can be applied
to a wide variety of BSM particle physics models around the GUT scale. We then
demonstrate how the procedure works for an explicit lepton flavour model based
on an A_4 family symmetry. The model is both predictive and phenomenologically
viable, and illustrates how tribrid inflation connects cosmological and
particle physics parameters. In particular, it predicts a relation between the
neutrino Yukawa coupling and the running of the spectral index alpha_s. We also
show how topological defects from the flavour symmetry breaking can be avoided
automatically.


title:
Inter-valley scattering induced by Coulomb interaction and disorder in
  carbon-nanotube quantum dots

abstract:
  We develop a theory of inter-valley Coulomb scattering in semiconducting
carbon-nanotube quantum dots, taking into account the effects of curvature and
chirality. Starting from the effective-mass description of single-particle
states, we study the two-electron system by fully including Coulomb
interaction, spin-orbit coupling, and short-range disorder. We find that the
energy level splittings associated with inter-valley scattering are nearly
independent of the chiral angle and, while smaller than those due to spin-orbit
interaction, large enough to be measurable.


title:
Constraining Explosion Type of Young Supernova Remnants Using 24 Micron
  Emission Morphology

abstract:
  Determination of the explosion type of supernova remnants (SNRs) can be
challenging, as SNRs are hundreds to thousands of years old and supernovae
(SNe) are classified based on spectral properties days after explosion.
Previous studies of thermal X-ray emission from Milky Way and Large Magellanic
Cloud (LMC) SNRs have shown that Type Ia and core-collapse (CC) SNRs have
statistically different symmetries, and thus these sources can be typed based
on their X-ray morphologies. In this paper, we extend the same technique, a
multipole expansion technique using power ratios, to infrared (IR) images of
SNRs to test whether they can be typed using the symmetry of their warm dust
emission as well. We analyzed archival Spitzer Space Telescope Multiband
Imaging Photometer (MIPS) 24 micron observations of the previously used X-ray
sample, and we find that the two classes of SNRs separate according to their IR
morphologies. The Type Ia SNRs are statistically more circular and mirror
symmetric than the CC SNRs, likely due to the different circumstellar
environments and explosion geometries of the progenitors. Broadly, our work
indicates that the IR emission retains information of the explosive origins of
the SNR and offers a new method to type SNRs based on IR morphology.


title:
Massive planar and non-planar double box integrals for light Nf
  contributions to gg->tt

abstract:
  We present the master integrals needed for the light fermionic two-loop
corrections to top quark pair production in the gluon fusion channel. Via the
method of differential equations we compute the results in terms of multiple
polylogarithms in a Laurent series about d=4, where d is the space-time
dimension. The most involved topology is a non-planar double box with one
internal mass. We employ the coproduct-augmented symbol calculus and show that
significant simplifications are possible for selected results using an
optimised set of multiple polylogarithms.


title:
A class of exactly solved assisted hopping models of active-absorbing
  state transitions on a line

abstract:
  We construct a class of assisted hopping models in one dimension in which a
particle can move only if it does not lie in an otherwise empty interval of
length greater than $n+1$. We determine the exact steady state by a mapping to
a gas of defects with only on-site interaction. We show that this system
undergoes a phase transition as a function of the density $\rho$ of particles,
from a low-density phase with all particles immobile for $\rho \le \rho_c =
\frac{1}{n+1}$, to an active state for $\rho > \rho_c$. The mean fraction of
movable particles in the active steady state varies as $(\rho -
\rho_c)^{\beta}$, for $\rho$ near $\rho_c$. We show that for the model with
range $n$, the exponent $\beta =n$, and thus can be made arbitrarily large.


title: A fast implicit method for time-dependent Hamilton-Jacobi PDEs

abstract:
  We present a new efficient computational approach for time-dependent
first-order Hamilton-Jacobi-Bellman PDEs. Since our method is based on a
time-implicit Eulerian discretization, the numerical scheme is unconditionally
stable, but discretized equations for each time-slice are coupled and
non-linear. We show that the same system can be re-interpreted as a
discretization of a static Hamilton-Jacobi-Bellman PDE on the same physical
domain. The latter was shown to be ``causal' in [Vladimirsky 2006], making fast
(non-iterative)methods applicable. The implicit discretization results in
higher computational cost per time slice compared to the explicit time
marching. However, the latter is subject to a CFL-stability condition, and the
implicit approach becomes significantly more efficient whenever the accuracy
demands on the time-step are less restrictive than the stability. We also
present a hybrid method, which aims to combine the advantages of both the
explicit and implicit discretizations. We demonstrate the efficiency of our
approach using several examples in optimal control of isotropic fixed-horizon
processes.


title:
Extended to Multi-Tilde-Bar Regular Expressions and Efficient Finite
  Automata Constructions

abstract:
  Several algorithms have been designed to convert a regular expression into an
equivalent finite automaton. One of the most popular constructions, due to
Glushkov and to McNaughton and Yamada, is based on the computation of the Null,
First, Last and Follow sets (called Glushkov functions) associated with a
linearized version of the expression. Recently Mignot considered a family of
extended expressions called Extended to multi-tilde-bar Regular Expressions
(EmtbREs) and he showed that, under some restrictions, Glushkov functions can
be defined for an EmtbRE. In this paper we present an algorithm which
efficiently computes the Glushkov functions of an unrestricted EmtbRE. Our
approach is based on a recursive definition of the language associated with an
EmtbRE which enlightens the fact that the worst case time complexity of the
conversion of an EmtbRE into an automaton is related to the worst case time
complexity of the computation of the Null function. Finally we show how to
extend the ZPC-structure to EmtbREs, which allows us to apply to this family of
extended expressions the efficient constructions based on this structure (in
particular the construction of the c-continuation automaton, the position
automaton, the follow automaton and the equation automaton).


title:
Labelled version of the almost bounded case of S. B. Rao's degree
  sequence conjecture

abstract:
  S. B. Rao conjectured that graphic sequences are well-quasi-ordered under an
inclusion based on induced subgraphs. This conjecture has now been proved by
Chudnovsky and Seymour. We give an independent short proof of the labelled
version of the almost bounded case of S. B. Rao's conjecture, the case where we
have a bound on the degree, but allow a bounded number of vertices to have
unbounded degree.


title:
High-precision photometry by telescope defocussing. V. WASP-15 and
  WASP-16

abstract:
  We present new photometric observations of WASP-15 and WASP-16, two
transiting extrasolar planetary systems with measured orbital obliquities but
without photometric follow-up since their discovery papers. Our new data for
WASP-15 comprise observations of one transit simultaneously in four optical
passbands using GROND on the MPG/ESO 2.2m telescope, plus coverage of half a
transit from DFOSC on the Danish 1.54m telescope, both at ESO La Silla. For
WASP-16 we present observations of four complete transits, all from the Danish
telescope. We use these new data to refine the measured physical properties and
orbital ephemerides of the two systems. Whilst our results are close to the
originally-determined values for WASP-15, we find that the star and planet in
the WASP-16 system are both larger and less massive than previously thought.


title: Calculation of the constant factor in the six-vertex model

abstract:
  In the present paper we calculate explicitly the constant factor $C$ in the
large $N$ asymptotics of the partition function $Z_N$ of the six-vertex model
with domain wall boundary conditions on the critical line between the
disordered and ferroelectric phases. On the critical line the weights $a,b,c$
of the model are parameterized by a parameter $\al>1$, as $a=\frac{\al-1}{2}$,
$b=\frac{\al+1}{2}$, $c=1$. The asymptotics of $Z_N$ on the critical line was
obtained earlier in the paper \cite{BL2} of Bleher and Liechty:
$Z_N=CF^{N^2}G^{\sqrt{N}}N^{1/4}\big(1+O(N^{-1/2})\big)$, where $F$ and $G$ are
given by explicit expressions, but the constant factor $C>0$ was not known. To
calculate the constant $C$, we find, by using the Riemann-Hilbert approach, an
asymptotic behavior of $Z_N$ in the double scaling limit, as $N$ and $\al$ tend
simultaneously to $\infty$ in such a way that $\frac{N}{\al}\to t\ge 0$. Then
we apply the Toda equation for the tau-function to find a structural form for
$C$, as a function of $\al$, and we combine the structural form of $C$ and the
double scaling asymptotic behavior of $Z_N$ to calculate $C$.


title:
Witness trees in the Moser-Tardos algorithmic Lov\'asz Local Lemma and
  Penrose trees in the hard core lattice gas

abstract:
  We point out a close connection between the Moser-Tardos algorithmic version
of the Lov\'asz Local Lemma, a central tool in probabilistic combinatorics, and
the cluster expansion of the hard core lattice gas in statistical mechanics. We
show that the notion of witness trees given by Moser and Tardos is essentially
coincident with that of Penrose trees in the Cluster expansion scheme of the
hard core gas. Such an identification implies that the Moser Tardos algorithm
is successful in a polynomial time if the Cluster expansion converges.


title: String Inflation After Planck 2013

abstract:
  We briefly summarize the impact of the recent Planck measurements for string
inflationary models, and outline what might be expected to be learned in the
near future from the expected improvement in sensitivity to the primordial
tensor-to-scalar ratio. We comment on whether these models provide sufficient
added value to compensate for their complexity, and ask how they fare in the
face of the new constraints on non-gaussianity and dark radiation. We argue
that as a group the predictions made before Planck agree well with what has
been seen, and draw conclusions from this about what is likely to mean as
sensitivity to primordial gravitational waves improves.


title: A Simple Policy for Multiple Queues with Size-Independent Service Times

abstract:
  We consider a service system with two Poisson arrival queues. A server
chooses which queue to serve at each moment. Once a queue is served, all the
customers will be served within a fixed amount of time. This model is useful in
studying airport shuttling or certain online computing systems. We propose a
simple yet optimal state-independent policy for this problem which is not only
easy to implement, but also performs very well.


title: Enumerating Cuspidal Curves on Toric Surfaces

abstract:
  Enumerative algebraic geometry deals with problems of counting geometric
objects defined algebraically, An important class of enumerative problems is
that of counting curves: given a class of curves in some projective variety
defined by fixing some algebraic or geometric invariants (such as degree, genus
and types of singularities), the problem usually takes the form of "how many
curves of that class pass through a configuration of n points in general
position?" Tropical Geometry deals with certain piecewise-linear complexes,
which arise as degeneration of families of complex algebraic varieties, and can
also be described algebraically using "max-plus" algebra, (The tropical
semi-field). The problem we solve is that of counting rational curves with one
cusp and certain number of nodes on toric surfaces, passing through a
configuration of sufficient points in general position. We show that that this
number equals the number of certain tropical curves counted with multiplicities
and we describe these curves and their multiplicities. The main tools are
tropicalization and patchworking. In tropicalization we pass from an
equisingular family of curves to a special limit fiber which can be described
in terms of tropical data and analytic data. We then classify these possible
limits, and use the patchworking theorem to reconstruct the families that
correspond to them.


title:
Model Sensitivity in Holographic Superconductors and their Deconstructed
  Cousins

abstract:
  Holographic models of superconductors successfully reproduce certain
experimental features of high-temperature superconductors, such as a large
gap-to-T_c ratio compared to that of conventional superconductors. By
deconstructing the extra dimension of these holographic models, similar
phenomenology is described by a class of models defined in the natural
dimension of the superconducting system. We analyze the sensitivity of certain
observables in holographic and deconstructed holographic superconductors to
details of the extra-dimensional spacetime. Our results support the notion that
certain quantitative successes of simple models of this type are accidental.
However, we also find a certain universal relationship between superconducting
observables.


title: Time-Dependent Charge-Order and Spin-Order Recovery in Striped Systems

abstract:
  Using time-dependent Ginzburg-Landau theory, we study the role of amplitude
and phase fluctuations in the recovery of charge and spin stripe phases in
response to a pump pulse that melts the orders. For parameters relevant to the
case where charge order precedes spin order thermodynamically, amplitude
recovery governs the initial time scales, while phase recovery controls
behavior at longer times. In addition to these intrinsic effects, there is a
longer spin re-orientation time scale related to the scattering geometry that
dominates the recovery of the spin phase. Coupling between the charge and spin
orders locks the amplitude and similarly the phase recovery, reducing the
number of distinct time scales. Our results well reproduce the major
experimental features of pump-probe x-ray diffraction measurements on the
striped nickelate La$_{1.75}$Sr$_{0.25}$NiO$_4$. They highlight the main idea
of this work, which is the use of time-dependent Ginzburg-Landau theory to
study systems with multiple coexisting order parameters.


title: Different Approaches to Community Evolution Prediction in Blogosphere

abstract:
  Predicting the future direction of community evolution is a problem with high
theoretical and practical significance. It allows to determine which
characteristics describing communities have importance from the point of view
of their future behaviour. Knowledge about the probable future career of the
community aids in the decision concerning investing in contact with members of
a given community and carrying out actions to achieve a key position in it. It
also allows to determine effective ways of forming opinions or to protect group
participants against such activities. In the paper, a new approach to group
identification and prediction of future events is presented together with the
comparison to existing method. Performed experiments prove a high quality of
prediction results. Comparison to previous studies shows that using many
measures to describe the group profile, and in consequence as a classifier
input, can improve predictions.


title:
Radio frequency spectroscopy measurement of the Land\'e g factor of the
  5D5/2 state of Ba+ with a single trapped ion

abstract:
  We report an improved measurement of the Land\'e g factor of the 5D5/2 state
of singly ionized barium. Measurements were performed on single Doppler-cooled
138Ba+ ions in linear Paul traps using two similar, independent apparatuses.
Transitions between Zeeman sublevels of the 6S1/2 and 5D5/2 states were driven
with two independent, stabilized radio-frequency synthesizers using a dedicated
electrode within each ion trap chamber. State detection within each Zeeman
manifold was achieved with a frequency-stabilized fiber laser operating at 1.76
microns. By calculating the ratio of the two Zeeman splittings, and using the
measured Land\'e g factor of the 6S1/2 state, we find a value of
1.200371(4stat)(6sys) for g of 5D5/2.


title: Toric and tropical compactifications of hyperplane complements

abstract:
  These lecture notes are based on lectures given by the author at the summer
school "Arrangements in Pyr\'en\'ees" in June 2012. We survey and compare
various compactifications of complex hyperplane arrangement complements. In
particular, we review the Gel'fand-MacPherson construction, Kapranov's visible
contours compactification, and De Concini and Procesi's wonderful
compactification. We explain how these constructions are unified by some ideas
from the modern origins of tropical geometry. The paper contains a few new
arguments intended to make the presentation as self-contained as possible.


title: Deep Chandra Observations of the Extended Gas Sloshing Spiral in A2029

abstract:
  Recent X-ray observations of galaxy clusters have shown that there is
substructure present in the intracluster medium (ICM), even in clusters that
are seemingly relaxed. This substructure is sometimes a result of sloshing of
the ICM, which occurs in cool core clusters that have been disturbed by an
off-axis merger with a sub-cluster or group. We present deep Chandra
observations of the cool core cluster Abell 2029, which has a sloshing spiral
extending radially outward from the center of the cluster to approximately 400
kpc at its fullest extent---the largest continuous spiral observed to date. We
find a surface brightness excess, a temperature decrement, a density
enhancement, an elemental abundance enhancement, and a smooth pressure profile
in the area of the spiral. The sloshing gas seems to be interacting with the
southern lobe of the central radio galaxy, causing it to bend and giving the
radio source a wide-angle tail (WAT) morphology. This shows that WATs can be
produced in clusters that are relatively relaxed on large scales. We explore
the interaction between heating and cooling in the central region of the
cluster. Energy injection from the active galactic nucleus (AGN) is likely
insufficient to offset the cooling, and sloshing may be an important additional
mechanism in preventing large amounts of gas from cooling to very low
temperatures.


title: Rehabilitating CIV-based black hole mass estimates in quasars

abstract:
  Currently, the ability to produce black hole mass estimates using the CIV
1549 line that are consistent with Hb mass estimates is uncertain, due in large
part to disagreement between velocity line width measurements for the two
lines. This discrepancy between Hb and CIV arises from the fact that both line
profiles are treated the same way in single-epoch scaling relationships based
on the assumption that the broad-line region is virialized, even though a
non-virialized emission component is often significant in the CIV line and
absent or weak in the Hb line. Using quasi-simultaneous optical and
ultra-violet spectra for a sample of 85 optically bright quasars with redshifts
in the range z=0.03-1.4, we present a significant step along the path to
rehabilitating the CIV line for black hole mass estimates. We show that the
residuals of velocity line width between CIV and Hb are significantly
correlated with the peak flux ratio of SiIV+OIV] 1400 to CIV. Using this
relationship, we develop a prescription for estimating black hole masses from
the ultra-violet spectrum that agree better with Hb-based masses than the
traditional CIV masses. The scatter between Hb and CIV masses is initially 0.43
dex in our sample and is reduced to 0.33 dex when using our prescription. The
peak flux ratio of SiIV+OIV] 1400 to CIV is an ultraviolet indicator of the
suite of spectral properties commonly known as "Eigenvector 1", thus the
reduction in scatter between CIV and Hb black hole masses is essentially due to
removing an Eigenvector 1 bias in CIV-based masses.


title: Analysis and rejection sampling of Wright-Fisher diffusion bridges

abstract:
  We investigate the properties of a Wright-Fisher diffusion process started
from frequency x at time 0 and conditioned to be at frequency y at time T. Such
a process is called a bridge. Bridges arise naturally in the analysis of
selection acting on standing variation and in the inference of selection from
allele frequency time series. We establish a number of results about the
distribution of neutral Wright-Fisher bridges and develop a novel rejection
sampling scheme for bridges under selection that we use to study their
behavior.


title: A linear distribution of orbits in compact planetary systems?

abstract:
  We report a linear ordering of orbits in a sample of multiple extrasolar
planetary systems with super-Earth planets. We selected 20 cases, mostly
discovered by the Kepler mission, hosting at least four planets within \sim 0.5
au. The semi-major axis a_n of an n-th planet in each system of this sample
obeys a(n) = a_1 + (n-1) \Delta a, where a_1 is the semi-major axis of the
innermost orbit and \Delta a is a spacing between subsequent planets, which are
specific for a particular system. For instance, the Kepler-33 system hosting
five super-Earth planets exhibits the relative deviations between the observed
and linearly predicted semi-major axes of only a few percent. At least half of
systems in the sample fulfill the linear law with a similar accuracy. We
explain the linear distribution of semi-major axes as a natural implication of
multiple chains of mean motion resonances between subsequent planets, which
emerge due to planet--disk interactions and convergent migration at early
stages of their evolution.


title: Analysis of data in the form of graphs

abstract:
  We discuss the problem of extending data mining approaches to cases in which
data points arise in the form of individual graphs. Being able to find the
intrinsic low-dimensionality in ensembles of graphs can be useful in a variety
of modeling contexts, especially when coarse-graining the detailed graph
information is of interest. One of the main challenges in mining graph data is
the definition of a suitable pairwise similarity metric in the space of graphs.
We explore two practical solutions to solving this problem: one based on
finding subgraph densities, and one using spectral information. The approach is
illustrated on three test data sets (ensembles of graphs); two of these are
obtained from standard graph generating algorithms, while the graphs in the
third example are sampled as dynamic snapshots from an evolving network
simulation.


title: Approximation Algorithms for Bayesian Multi-Armed Bandit Problems

abstract:
  In this paper, we consider several finite-horizon Bayesian multi-armed bandit
problems with side constraints which are computationally intractable (NP-Hard)
and for which no optimal (or near optimal) algorithms are known to exist with
sub-exponential running time. All of these problems violate the standard
exchange property, which assumes that the reward from the play of an arm is not
contingent upon when the arm is played. Not only are index policies suboptimal
in these contexts, there has been little analysis of such policies in these
problem settings. We show that if we consider near-optimal policies, in the
sense of approximation algorithms, then there exists (near) index policies.
Conceptually, if we can find policies that satisfy an approximate version of
the exchange property, namely, that the reward from the play of an arm depends
on when the arm is played to within a constant factor, then we have an avenue
towards solving these problems. However such an approximate version of the
idling bandit property does not hold on a per-play basis and are shown to hold
in a global sense. Clearly, such a property is not necessarily true of
arbitrary single arm policies and finding such single arm policies is
nontrivial. We show that by restricting the state spaces of arms we can find
single arm policies and that these single arm policies can be combined into
global (near) index policies where the approximate version of the exchange
property is true in expectation. The number of different bandit problems that
can be addressed by this technique already demonstrate its wide applicability.


title:
A lack of short-period multiplanet systems with close-proximity pairs
  and the curious case of Kepler 42

abstract:
  Many Kepler multiplanet systems have planet pairs near low-order, mean-motion
resonances. In addition, many Kepler multiplanet systems have planets with
orbital periods less than a few days. With the exception of Kepler-42, however,
there are no examples of systems with both short orbital periods and nearby
companion planets while our statistical analysis predicts ~17 such pairs. For
orbital periods of the inner planet that are less than three days, the minimum
period ratio of adjacent planet pairs follows the rough constraint P_2/P_1 >~
2.3 (P_1/day)^(-2/3). This absence is not due to a lack of planets with short
orbital periods. We also show a statistically significant excess of small,
single candidate systems with orbital periods below 3 days over the number of
multiple candidate systems with similar periods---perhaps a small-planet
counterpart to the hot Jupiters.


title:
Unitary equivalence and similarity to Jordan models for weak
  contractions of class $C_0$

abstract:
  We obtain results on the unitary equivalence of weak contractions of class
$C_0$ to their Jordan models under an assumption on their commutants. In
particular, our work addresses the case of arbitrary finite multiplicity. The
main tool is the theory of boundary representations due to Arveson. We also
generalize and improve previously known results concerning unitary equivalence
and similarity to Jordan models when the minimal function is a Blaschke
product.


title: A Continuum Generalization of the Ising Model

abstract:
  The Lenz-Ising model has served for almost a century as a basis for
understanding ferromagnetism, and has become a paradigmatic model for phase
transitions in statistical mechanics. While retaining the Ising energy
arguments, we use techniques previously applied to sociophysics to propose a
continuum model. Our formulation results in an integro-differential equation
that has several advantages over the traditional version: it allows for
asymptotic analysis of phase transitions, material properties, and the dynamics
of the formation of magnetic domains.


title: Scalable Successive-Cancellation Hardware Decoder for Polar Codes

abstract:
  Polar codes, discovered by Ar{\i}kan, are the first error-correcting codes
with an explicit construction to provably achieve channel capacity,
asymptotically. However, their error-correction performance at finite lengths
tends to be lower than existing capacity-approaching schemes. Using the
successive-cancellation algorithm, polar decoders can be designed for very long
codes, with low hardware complexity, leveraging the regular structure of such
codes. We present an architecture and an implementation of a scalable hardware
decoder based on this algorithm. This design is shown to scale to code lengths
of up to N = 2^20 on an Altera Stratix IV FPGA, limited almost exclusively by
the amount of available SRAM.


title: Generalized Beta Divergence

abstract:
  This paper generalizes beta divergence beyond its classical form associated
with power variance functions of Tweedie models. Generalized form is
represented by a compact definite integral as a function of variance function
of the exponential dispersion model. This compact integral form simplifies
derivations of many properties such as scaling, translation and expectation of
the beta divergence. Further, we show that beta divergence and (half of) the
statistical deviance are equivalent measures.


title:
The convergence of regional house prices in the USA in the context of
  the stress testing of financial institutions

abstract:
  I studied the convergence of regional house prices to national prices in USA
by analyzing time-series of house price indices of 9 Census Divisions. I found
the evidence of the convergence in some parts of the country using asymmetric
unit root tests. The fact that the evidence of the convergence is not present
in large parts of the country raises an issue of execution and interpretation
of results of Federal Reserve Bank's annual stress testing of the US banking
system.


title:
Fast Marching Tree: a Fast Marching Sampling-Based Method for Optimal
  Motion Planning in Many Dimensions

abstract:
  In this paper we present a novel probabilistic sampling-based motion planning
algorithm called the Fast Marching Tree algorithm (FMT*). The algorithm is
specifically aimed at solving complex motion planning problems in
high-dimensional configuration spaces. This algorithm is proven to be
asymptotically optimal and is shown to converge to an optimal solution faster
than its state-of-the-art counterparts, chiefly PRM* and RRT*. The FMT*
algorithm performs a "lazy" dynamic programming recursion on a predetermined
number of probabilistically-drawn samples to grow a tree of paths, which moves
steadily outward in cost-to-arrive space. As a departure from previous analysis
approaches that are based on the notion of almost sure convergence, the FMT*
algorithm is analyzed under the notion of convergence in probability: the extra
mathematical flexibility of this approach allows for convergence rate
bounds--the first in the field of optimal sampling-based motion planning.
Specifically, for a certain selection of tuning parameters and configuration
spaces, we obtain a convergence rate bound of order $O(n^{-1/d+\rho})$, where
$n$ is the number of sampled points, $d$ is the dimension of the configuration
space, and $\rho$ is an arbitrarily small constant. We go on to demonstrate
asymptotic optimality for a number of variations on FMT*, namely when the
configuration space is sampled non-uniformly, when the cost is not arc length,
and when connections are made based on the number of nearest neighbors instead
of a fixed connection radius. Numerical experiments over a range of dimensions
and obstacle configurations confirm our theoretical and heuristic arguments by
showing that FMT*, for a given execution time, returns substantially better
solutions than either PRM* or RRT*, especially in high-dimensional
configuration spaces and in scenarios where collision-checking is expensive.


title: On D\'evissage for Witt groups

abstract:
  In this paper we extend and apply the work of Paul Balmer and others on
derived and triangular Witt Groups. We obtain a generalized form of
d\'{e}vissage for derived Witt Groups over Cohen-Macaulay rings.


title: A cost-benefit analysis of low latency via added utilization

abstract:
  Several recently proposed techniques achieve latency reduction by trading it
off for some amount of additional bandwidth usage. But how would one quantify
whether the tradeoff is actually beneficial in a given system? We develop an
economic cost vs. benefit analysis for answering this question. We use the
analysis to derive a benchmark for wide-area client-server applications, and
demonstrate how it can be applied to reason about a particular latency saving
technique --- redundant DNS requests.


title:
Simple learning models can illuminate biased results from choice
  titration experiments

abstract:
  The choice titration procedure presents a subject with a repeated choice
between a standard option that always provides the same reward and an adjusting
option for which the reward schedule is adjusted based on the subjects previous
choices. The procedure is designed to determine the point of indifference
between the two schedules which is then used to estimate a utility equivalence
point between the two options. Analyzing the titration procedure as a Markov
birth death process, we show that a large class of reinforcement learning
models invariably generates a titration bias, and that the bias varies
non-linearly with the reward value. We treat several titration procedures,
presenting analytic results for some simple learning models and simulation
results for more complex models. These results suggest that results from
titration experiments are likely to be biased and that inferences based on the
titration experiments may need to be reconsidered.


title:
Beyond Stacking: A Maximum-Likelihood Method to Constrain Radio Source
  Counts Below the Detection Threshold

abstract:
  We present a statistical method based on a maximum likelihood approach to
constrain the number counts of extragalactic sources below the nominal
flux-density limit of continuum imaging surveys. We extract flux densities from
a radio map using positional information from an auxiliary catalogue and show
that we can model the number counts of this undetected population down to flux
density levels well below the detection threshold of the radio survey. We
demonstrate the capabilities that our method will have with future generation
wide-area radio surveys by performing simulations over various sky areas. We
show that it is possible to accurately constrain the number counts of the
simulated distribution down to one tenth of the flux noise rms with just a sky
area of 100 deg$^2$. We then test the application of our method using data from
the Faint Images of the Radio Sky at Twenty-Centimeters survey (FIRST). We
extract flux densities from the FIRST map, sensitive to 150 $\mu$Jy/beam (1
$\sigma$), using the positional information from a catalogue in the same field,
also acquired at the same frequency, sensitive to 12 $\mu$Jy/beam (1 $\sigma$).
Implementing our method, with known source positions, we are able to recover
the right differential number counts of the noise-dominated FIRST map fluxes
down to a flux density level which is one-tenth the FIRST detection threshold.


title:
Anisotropic Fermi Contour of (001) GaAs Electrons in Parallel Magnetic
  Fields

abstract:
  We demonstrate a severe Fermi contour anisotropy induced by the application
of a parallel magnetic field to high-mobility electrons confined to a
30-nm-wide (001) GaAs quantum well. We study commensurability oscillations,
namely geometrical resonances of the electron orbits with a unidirectional,
surface-strain-induced, periodic potential modulation, to directly probe the
size of the Fermi contours along and perpendicular to the parallel field. Their
areas are obtained from the Shubnikov-de Haas oscillations. Our experimental
data agree semi-quantitatively with the results of parameter-free calculations
of the Fermi contours but there are significant discrepancies.


title:
Exact and fixed-parameter algorithms for metro-line crossing
  minimization problems

abstract:
  A metro-line crossing minimization problem is to draw multiple lines on an
underlying graph that models stations and rail tracks so that the number of
crossings of lines becomes minimum. It has several variations by adding
restrictions on how lines are drawn. Among those, there is one with a
restriction that line terminals have to be drawn at a verge of a station, and
it is known to be NP-hard even when underlying graphs are paths. This paper
studies the problem in this setting, and propose new exact algorithms. We first
show that a problem to decide if lines can be drawn without crossings is solved
in polynomial time, and propose a fast exponential algorithm to solve a
crossing minimization problem. We then propose a fixed-parameter algorithm with
respect to the multiplicity of lines, which implies that the problem is FPT.


title:
Entanglement classification of 2 X 2 X 2 X d quantum systems via the
  ranks of the multiple coefficient matrices

abstract:
  The coefficient matrix is an efficient tool in entanglement classification
under stochastic local operation and classical communication. In this work, we
take all the ranks of the coefficient matrices into account in the method of
entanglement classification, and give the entanglement classification procedure
for arbitrary-dimensional multipartite pure states under stochastic local
operation and classical communication. As a main application, we study the
entanglement classification for quantum systems in the Hilbert space ${\cal H}
= \mathbb{C}^2 \otimes \mathbb{C}^2 \otimes \mathbb{C}^2 \otimes \mathbb{C}^d$
in terms of the ranks of the coefficient matrices.


title:
Crystal Structure and Elastic Properties of Hypothesized MAX Phase-like
  Compound (Cr2Hf)2Al3C3

abstract:
  The term "MAX phase" refers to a very interesting and important class of
layered ternary transition-metal carbides and nitrides with a novel combination
of both metal and ceramic-like properties that have made these materials highly
regarded candidates for numerous technological and engineering applications.
Using (Cr2Hf)2Al3C3 as an example, we demonstrate the possibility of
incorporating more types of elements into a MAX phase while maintaining the
crystallinity, instead of creating solid-solution phases. The crystal structure
and elastic properties of MAX-like (Cr2Hf)2Al3C3 are studied using the Vienna
Ab initio Simulation Package. Unlike MAX phases with a hexagonal symmetry
(P63/mmc, #194), (Cr2Hf)2Al3C3 crystallizes in the monoclinic space group of
P21/m (#11) with lattice parameters of a = 5.1739 {\AA}, b = 5.1974 {\AA}, c =
12.8019 {\AA}; {\alpha} = {\beta} = 90{\deg}, {\gamma} = 119.8509{\deg}. Its
structure is found to be energetically much more favorable with an energy (per
formula unit) of -102.11 eV, significantly lower than those of the allotropic
segregation (-100.05 eV) and solid-solution (-100.13 eV) phases. Calculations
using a stress vs. strain approach and the VRH approximation for polycrystals
also show that (Cr2Hf)2Al3C3 has outstanding elastic moduli.


title: Adjusting for Misclassification: A Three-Phase Sampling Approach

abstract:
  The United States Department of Agriculture's National Agricultural
Statistics Service (NASS) conducts the June Agricultural Survey (JAS) annually.
Substantial misclassification occurs during the pre-screening process and from
field-estimating farm status for non-response and inaccessible records,
resulting in a biased estimate of the number of US farms from the JAS. Here the
Annual Land Utilization Survey (ALUS) is proposed as a follow-on survey to the
JAS to adjust the estimates of the number of US farms and other important
variables. A three-phase survey design-based estimator is developed for the
JAS-ALUS with non-response adjustment for the second phase (ALUS). A
design-unbiased estimator of the variance is provided in explicit form.


title:
Encoding Petri Nets in Answer Set Programming for Simulation Based
  Reasoning

abstract:
  One of our long term research goals is to develop systems to answer realistic
questions (e.g., some mentioned in textbooks) about biological pathways that a
biologist may ask. To answer such questions we need formalisms that can model
pathways, simulate their execution, model intervention to those pathways, and
compare simulations under different circumstances. We found Petri Nets to be
the starting point of a suitable formalism for the modeling and simulation
needs. However, we need to make extensions to the Petri Net model and also
reason with multiple simulation runs and parallel state evolutions. Towards
that end Answer Set Programming (ASP) implementation of Petri Nets would allow
us to do both. In this paper we show how ASP can be used to encode basic Petri
Nets in an intuitive manner. We then show how we can modify this encoding to
model several Petri Net extensions by making small changes. We then highlight
some of the reasoning capabilities that we will use to accomplish our ultimate
research goal.