title:
Light-quark two-loop corrections to heavy-quark pair production in the
  gluon fusion channel

abstract:
  We calculate the two-loop corrections to heavy-quark pair production in the
gluon fusion channel which arise from diagrams involving a closed light-quark
loop. The calculation is carried out by keeping the exact dependence on the
heavy-quark mass. The analytic results are written in terms of logarithms,
classical polylogarithms Li_n (n=2,3,4), and genuine multiple polylogarithms
Li_{2,2}. The functional arguments are rational expressions of two independent
external invariants and they are chosen in such a way that the functions are
real in all the physical phase-space points. Through systematic changes in the
functional basis, we obtain expansions of the results in both the production
threshold and small mass limits.


title:
Locating the "missing" baryons with extragalactic dispersion measure
  estimates

abstract:
  Recently, Thornton and coworkers (2013) confirmed a class of millisecond
radio bursts likely of extragalactic origin that is well-suited for estimating
dispersion measures (DMs). We calculate the probability distribution of DM(z)
in different models for how the cosmic baryons are distributed (both
analytically and with cosmological simulations). We show that the distribution
of DM is quite sensitive to whether the "missing" baryons lie around the virial
radius of 10^11-10^13 Msun halos or further out, which is not easily
constrained with other observational techniques. The intrinsic contribution to
DM from each source could complicate studies of the extragalactic contribution.
This difficulty is avoided by stacking based on the impact parameter to
foreground galaxies. We show that a stacking analysis using a sample of ~100 DM
measurements from arcminute-localized, z >~ 0.5 sources would place interesting
constraints at 0.2-2 halo virial radii on the baryonic mass profile surrounding
different galaxy types. Conveniently for intergalactic studies, sightlines that
intersect intervening galactic disks should be easily identified owing to
scattering. A detectable level of scattering may also result from turbulence in
the circumgalactic medium.


title: The Pulsation-Rotation Interaction: Greatest Hits and the B-Side

abstract:
  It has long been known that rotation can have an appreciable impact on
stellar pulsation --- by modifying the usual p and g modes found in the
non-rotating case, and by introducing new classes of mode. However, it's only
relatively recently that advances in numerical simulations and complementary
theoretical treatments have enabled us to model these phenomena in any great
detail. In this talk I'll review highlights in this area (the 'Greatest Hits'),
before considering the flip side (or the 'B-side', for those of us old enough
to remember vinyl records) of the pulsation-rotation interaction: how pulsation
can itself influence internal rotation profiles.


title: Unquenched massive flavors and flows in Chern-Simons matter theories

abstract:
  We construct a holographic dual to the three-dimensional ABJM Chern-Simons
matter theory with unquenched massive flavors. The flavor degrees of freedom
are introduced by means of D6-branes extended along the gauge theory directions
and delocalized in the internal space. To find the solution we have to solve
the supergravity equations of motion with the source terms introduced by the
D6-branes. The background we get is a running solution representing the
renormalization group flow between two fixed points, at the IR and the UV, in
both of which the geometry is of the form AdS_4 x M_6, where M_6 is a
six-dimensional compact manifold. Along the flow, N=1 supersymmetry is
preserved and the flavor group is Abelian. The flow is generated by changing
the quark mass m_q. When m_q is very large we recover the original unflavored
ABJM solution, while for m_q very small our solution becomes asymptotically
equivalent to the one found recently for massless smeared flavors. We study the
effects of the dynamical quarks as their mass is varied on different
observables, such as the holographic entanglement entropy, the quark-antiquark
potential, the two-point functions of high dimension bulk operators, and the
mass spectrum of mesons.


title: Spectral Distortion in a Radially Inhomogeneous Cosmology

abstract:
  The spectral distortion of the cosmic microwave background blackbody spectrum
in a radially inhomogeneous spacetime, designed to exactly reproduce a
LambdaCDM expansion history along the past light cone, is shown to exceed the
upper bound established by COBE-FIRAS by a factor of approximately 3700. This
simple observational test helps uncover a slew of pathological features that
lie hidden inside the past light cone, including a radially contracting phase
at decoupling and, if followed to its logical extreme, a naked singularity at
the radially inhomogeneous Big Bang.


title: GYRE: A New Open-Source Stellar Oscillation Code

abstract:
  We introduce GYRE, a new open-source stellar oscillation code which solves
the adiabatic/non-adiabatic pulsation equations using a novel Magnus Multiple
Shooting (MMS) numerical scheme. The code has a global error scaling of up to
6th order in the grid spacing, and can therefore achieve high accuracy with few
grid points. It is moreover robust and efficiently makes use of multiple
processor cores and/or nodes. We present an example calculation using GYRE, and
discuss recent work to integrate GYRE into the asteroseismic optimization
module of the MESA stellar evolution code.


title:
A Chandra view of the clumpy reflector at the heart of the Circinus
  galaxy

abstract:
  We present a spectral and imaging analysis of the X-ray reflecting structure
at the heart of the Circinus galaxy, investigating the innermost regions
surrounding the central black hole. By studying an archival 200 ks Chandra
ACIS-S observation, we are able to image the extended clumpy structure
responsible for both cold reflection of the primary radiation and neutral iron
Ka line emission. We measure an excess of the equivalent width of the iron Ka
line which follows an axisymmetric geometry around the nucleus on a hundred pc
scale. Spectra extracted from different regions confirm a scenario in which the
dominant mechanism is the reflection of the nuclear radiation from
Compton-thick gas. Significant differences in the equivalent width of the iron
Ka emission line (up to a factor of 2) are found. It is argued that these
differences are due to different scattering angles with respect to the line of
sight rather than to different iron abundances.


title:
Hubble Space Telescope and Ground-Based Observations of the Type Iax
  Supernovae SN 2005hk and SN 2008A

abstract:
  We present Hubble Space Telescope (HST) and ground-based optical and
near-infrared observations of SN 2005hk and SN 2008A, typical members of the
Type Iax class of supernovae (SNe). Here we focus on late-time observations,
where these objects deviate most dramatically from all other SN types. Instead
of the dominant nebular emission lines that are observed in other SNe at late
phases, spectra of SNe 2005hk and 2008A show lines of Fe II, Ca II, and Fe I
more than a year past maximum light, along with narrow [Fe II] and [Ca II]
emission. We use spectral features to constrain the temperature and density of
the ejecta, and find high densities at late times, with n_e >~ 10^9 cm^-3. Such
high densities should yield enhanced cooling of the ejecta, making these
objects good candidates to observe the expected "infrared catastrophe," a
generic feature of SN Ia models. However, our HST photometry of SN 2008A does
not match the predictions of an infrared catastrophe. Moreover, our HST
observations rule out a "complete deflagration" that fully disrupts the white
dwarf for these peculiar SNe, showing no evidence for unburned material at late
times. Deflagration explosion models that leave behind a bound remnant can
match some of the observed properties of SNe Iax, but no published model is
consistent with all of our observations of SNe 2005hk and 2008A.


title:
Low Masses and High Redshifts: The Evolution of the Mass-Metallicity
  Relation

abstract:
  We present the first robust measurement of the high redshift mass-metallicity
(MZ) relation at 10^{8}< M/M_{\sun} < 10^{10}, obtained by stacking spectra of
83 emission-line galaxies with secure redshifts between 1.3 < z < 2.3. For
these redshifts, infrared grism spectroscopy with the Hubble Space Telescope
Wide Field Camera 3 is sensitive to the R23 metallicity diagnostic:
([OII]3726,3729 + [OIII] 4959,5007)/H\beta. Using spectra stacked in four mass
quartiles, we find a MZ relation that declines significantly with decreasing
mass, extending from 12+log(O/H) = 8.8 at M=10^{9.8} M_{\sun} to 12+log(O/H)=
8.2 at M=10^{8.2} M_{\sun}. After correcting for systematic offsets between
metallicity indicators, we compare our MZ relation to measurements from the
stacked spectra of galaxies with M>10^{9.5} M_{\sun} and z~2.3. Within the
statistical uncertainties, our MZ relation agrees with the z~2.3 result,
particularly since our somewhat higher metallicities (by around 0.1 dex) are
qualitatively consistent with the lower mean redshift z=1.76 of our sample. For
the masses probed by our data, the MZ relation shows a steep slope which is
suggestive of feedback from energy-driven winds, and a cosmological downsizing
evolution where high mass galaxies reach the local MZ relation at earlier
times. In addition, we show that our sample falls on an extrapolation of the
star-forming main sequence (the SFR-M_{*} relation) at this redshift. This
result indicates that grism emission-line selected samples do not have
preferentially high SFRs. Finally, we report no evidence for evolution of the
mass-metallicity-SFR plane; our stack-averaged measurements show excellent
agreement with the local relation.


title:
The role of galaxy interaction in the SFR-M relation: characterizing
  morphological properties of Herschel-selected galaxies at 0.2<z<1.5

abstract:
  Galaxy interactions/mergers have been shown to dominate the population of IR
luminous galaxies (log(LIR)>11.6Lsun) in the local Universe (z<0.25). Recent
studies based on the relation between galaxies' star formation rates and
stellar mass (the SFR-M relation or the galaxy main sequence (MS)) have
suggested that galaxy interaction/mergers may only become significant when
galaxies fall well above the galaxy MS. Since the typical SFR at given M
increases with redshift, the existence of galaxy MS implies that massive,
IR-luminous galaxies at high-z may not necessarily be driven by galaxy
interactions. We examine the role of galaxy interactions in the SFR-M relation
by carrying out a morphological analysis of 2084 Herschel-selected galaxies at
0.2 < z < 1.5 in the COSMOS field. Herschel-PACS and -SPIRE observations
covering the full 2-deg^2 COSMOS field provide one of the largest far-IR
selected samples of high-redshift galaxies with well-determined redshifts to
date, with sufficient sensitivity at z ~ 1, to sample objects lying on and
above the galaxy MS. Using a detailed visual classification scheme, we show
that the fraction of "disk galaxies" decreases and the fraction of "irregular"
galaxies increases systematically with increasing LIR out to z ~ 1.5 and z ~
1.0, respectively. At log(LIR) > 11.5 Lsun, >50% of the objects show evident
features of strongly interacting/merger systems, where this percentage is
similar to the studies of local IR-luminous galaxies. The fraction of
interacting/merger systems also systematically increases with the deviation
from the SFR-M relation, supporting the view that galaxies fall above the MS
are more dominated by mergers than the MS galaxies. Meanwhile, we find that
~18% of massive IR-luminous MS galaxies are classified as interacting systems,
where this population may not evolve through the evolutionary track predicted
by a simple gas exhaustion model.


title:
Cosmology with Minkowski functionals and moments of the weak lensing
  convergence field

abstract:
  We compare the efficiency of moments and Minkowski functionals (MFs) in
constraining the subset of cosmological parameters (Omega_m,w,sigma_8) using
simulated weak lensing convergence maps. We study an analytic perturbative
expansion of the MFs in terms of the moments of the convergence field and of
its spatial derivatives. We show that this perturbation series breaks down on
smoothing scales below 5', while it shows a good degree of convergence on
larger scales (15'). Most of the cosmological distinguishing power is lost when
the maps are smoothed on these larger scales. We also show that, on scales
comparable to 1', where the perturbation series does not converge, cosmological
constraints obtained from the MFs are approximately 1.5-2 times better than the
ones obtained from the first few moments of the convergence distribution ---
provided that the latter include spatial information, either from moments of
gradients, or by combining multiple smoothing scales. Including either a set of
these moments or the MFs can significantly tighten constraints on cosmological
parameters, compared to the conventional method of using the power spectrum
alone.


title: Slavnov-Taylor Identities for Primordial Perturbations

abstract:
  Correlation functions of adiabatic modes in cosmology are constrained by an
infinite number of consistency relations, which relate N+1-point correlation
functions with a soft-momentum scalar or tensor mode to a symmetry
transformation on N-point correlation functions of hard-momentum modes. They
constrain, at each order n, the q^n behavior of the soft limits. In this paper
we show that all consistency relations derive from a single, master identity,
which follows from the Slavnov-Taylor identity for spatial diffeomorphisms.
This master identity is valid at any value of q and therefore goes beyond the
soft limit. By differentiating it n times with respect to the soft momentum, we
recover the consistency relations at each q order. Our approach underscores the
role of spatial diffeomorphism invariance at the root of cosmological
consistency relations. It also offers new insights on the necessary conditions
for their validity: a physical contribution to the vertex functional must
satisfy certain analyticity properties in the soft limit in order for the
consistency relations to hold. For standard inflationary models, this is
equivalent to requiring that mode functions have constant growing-mode
solutions. For more exotic models in which modes do not "freeze" in the usual
sense, the analyticity requirement offers an unambiguous criterion.


title: Flavored Dark Matter and R-Parity Violation

abstract:
  Minimal Flavor Violation offers an alternative symmetry rationale to R-parity
conservation for the suppression of proton decay in supersymmetric extensions
of the Standard Model. The naturalness of such theories is generically under
less tension from LHC searches than R-parity conserving models. The flavor
symmetry can also guarantee the stability of dark matter if it carries flavor
quantum numbers. We outline general features of supersymmetric flavored dark
matter (SFDM) models within the framework of MFV SUSY. A simple model of top
flavored dark matter is presented. If the dark matter is a thermal relic, then
nearly the entire parameter space of the model is testable by upcoming direct
detection and LHC searches.


title:
Milliarcsec-scale radio emission of ultraluminous X-ray sources: steady
  jet emission from an intermediate-mass black hole?

abstract:
  The origin of the high X-ray luminosities of most ultraluminous X-ray sources
(ULXs) still remains poorly understood. Most of the scenarios proposed to
explain their nature assume that ULXs are powered by accretion on to a black
hole (BH). In this case, the detection of compact radio emission and the
location of the ULXs in the Fundamental Plane (X-ray versus radio-luminosity
plane) can provide an estimate of the ULX BH mass and help address the question
of their physical nature. We present the results of a high-resolution (very
long baseline interferometry) radio observational campaign aimed at detecting
and studying compact radio emission in four ULXs with known radio counterparts.
We find that one of the targets (N4559-X4) was previously misclassified: its
low X-ray luminosity indicates that the source is not a ULX. No
milliarcsec-scale radio emission is detected for N4559-X4 nor for the ULXs
N4490-X1 and N5194-X2, for which upper limits on the radio luminosities are
estimated. These limits argue strongly against the presence of supermassive BHs
in these three systems. For N4559-X4, the low X-ray luminosity and the ratio of
the radio and X-ray luminosities suggest the presence of an X-ray binary.
Compact radio emission is detected for the ULX N5457-X9 within its
\textit{Chandra} positional error, making N5457-X9 a potential
intermediate-mass BH with steady jet emission.


title: Recent developments in transport phenomena in Weyl semimetals

abstract:
  The last decade has witnessed great advancements in the science and
engineering of systems with unconventional band structures, seeded by studies
of graphene and topological insulators. While the band structure of graphene
simulates massless relativistic electrons in two dimensions, topological
insulators have bands that wind non-trivially over momentum space in a certain
abstract sense. Over the last couple of years, enthusiasm has been burgeoning
in another unconventional and topological (although, not quite in the same
sense as topological insulators) phase -- the Weyl Semimetal. In this phase,
electrons mimic Weyl fermions that are well-known in high-energy physics, and
inherit many of their properties, including an apparent violation of charge
conservation known as the Chiral Anomaly. In this review, we recap some of the
unusual transport properties of Weyl semimetals discussed in the literature so
far, focusing on signatures whose roots lie in the anomaly. We also mention
several proposed realizations of this phase in condensed matter systems, since
they were what arguably precipitated activity on Weyl semimetals in the first
place.


title: Outflow and hot dust emission in high redshift quasars

abstract:
  Correlations of hot dust emission with outflow properties are investigated,
based on a large z~2 non-broad absorption lines quasar sample built from the
Wide-field Infrared Survey and the Sloan Digital Sky Survey data releases. We
use the near infrared slope and the infrared to UV luminosity ratio to indicate
the hot dust emission relative to the emission from the accretion disk. In our
luminous quasars, these hot dust emission indicators are almost independent of
the fundamental parameters, such as luminosity, Eddington ratio and black hole
mass, but moderately dependent on the blueshift and asymmetry index (BAI) and
full width at half-maximum (FWHM) of CIV lines. Interestingly, the latter two
correlations dramatically strengthen with increasing Eddington ratio. We
suggest that, in high Eddington ratio quasars, CIV regions are dominated by
outflows so the BAI and FWHM(CIV) can reliably reflect the general properties
and velocity of outflows, respectively. While in low Eddington ratio quasars,
CIV lines are primarily emitted by virialized gas so the BAI and FWHM(CIV)
become less sensitive to outflows. Therefore, the correlations for the highest
Eddington ratio quasars are more likely to represent the true dependence of hot
dust emission on outflows and the correlations for the entire sample are
significantly diluted by the low Eddington ratio quasars. Our results show that
an outflow with a large BAI or velocity can double the hot dust emission on
average. We suggest that outflows either contain hot dust in themselves or
interact with the dusty interstellar medium or torus.


title: Dimension-free Maximal Inequalities for Spherical Means in the Hypercube

abstract:
  We extend the main result of Harrow, Kolla, and Schulman -- the existence of
dimension-free $L^2$-bounds for the spherical maximal function in the hypercube
-- to all $L^p, p > 1$. Our approach is motivated by the spectral technique
developed by Stein and Nevo and Stein in the context of pointwise ergodic
theorems on general groups. We provide an example which demonstrates that no
dimension-free weak-type (1-1) bound exists at the endpoint.


title:
Metabolic evolution of a deep-branching hyperthermophilic
  chemoautotrophic bacterium

abstract:
  Aquifex aeolicus is a deep-branching hyperthermophilic chemoautotrophic
bacterium restricted to hydrothermal vents and hot springs. These
characteristics make it an excellent model system for studying the early
evolution of metabolism. Here we present the whole-genome metabolic network of
this organism and examine in detail the driving forces that have shaped it. We
make extensive use of phylometabolic analysis, a method we recently introduced
that generates trees of metabolic phenotypes by integrating phylogenetic and
metabolic constraints. We reconstruct the evolution of a range of metabolic
sub-systems, including the reductive citric acid (rTCA) cycle, as well as the
biosynthesis and functional roles of several amino acids and cofactors. We show
that A. aeolicus uses the reconstructed ancestral pathways within many of these
sub-systems, and highlight how the evolutionary interconnections between
sub-systems facilitated several key innovations. Our analyses further highlight
three general classes of driving forces in metabolic evolution. One is the
duplication and divergence of genes for enzymes as these progress from lower to
higher substrate specificity, improving the kinetics of certain sub-systems. A
second is the kinetic optimization of established pathways through fusion of
enzymes, or their organization into larger complexes. The third is the
minimization of the ATP unit cost to synthesize biomass, improving
thermodynamic efficiency. Quantifying the distribution of these classes of
innovations across metabolic sub-systems and across the tree of life will allow
us to assess how a tradeoff between maximizing growth rate and growth
efficiency has shaped the long-term metabolic evolution of the biosphere.


title: Dependence of solar plasma flows on magnetic field obliquity

abstract:
  Interactions between flows and magnetic fields in the Sun's plasma can change
surface waves and flows near active regions, are evident in cyclic changes of
large-scale phenomena such as the meridional circulation, and contribute to
dynamics in the long-term solar magnetic cycle, e.g. during the recent
prolonged solar minimum. We investigate possible relationships between these
phenomena.
  We have observed changes in solar surface flow patterns in active regions,
dependent on magnetic field strength and orientation, consistent with the
theoretically predicted Proctor Effect. Other researchers have observed
relationships between changes in solar magnetic fields and meridional
circulation flows. We explore similarities between the Proctor Effect and the
observed interdependence of larger-scale magnetic fields and flows. This may
contribute to understanding of fundamental solar convection and dynamo
processes, e.g. the prolonged magnetic minimum of the most recent cycle.


title:
Multi-component symmetry-projected approach for molecular ground state
  correlations

abstract:
  The symmetry-projected Hartree--Fock ansatz for the electronic structure
problem can efficiently account for static correlation in molecules, yet it is
often unable to describe dynamic correlation in a balanced manner. Here, we
consider a multi-component, systematically-improvable approach, that accounts
for all ground state correlations. Our approach is based on linear combinations
of symmetry-projected configurations built out of a set of non-orthogonal,
variationally optimized determinants. The resulting wavefunction preserves the
symmetries of the original Hamiltonian even though it is written as a
superposition of deformed (broken-symmetry) determinants. We show how short
expansions of this kind can provide a very accurate description of the
electronic structure of simple chemical systems such as the nitrogen and the
water molecules, along the entire dissociation profile. In addition, we apply
this multi-component symmetry-projected approach to provide an accurate
interconversion profile among the peroxo and bis($\mu$-oxo) forms of
[Cu$_2$O$_2$]$^{2+}$, comparable to other state-of-the-art quantum chemical
methods.


title:
Polytropic spheres with electric charge: compact stars, the
  Oppenheimer-Volkoff and Buchdahl limits, and quasiblack holes

abstract:
  We explore a class of compact charged spheres made of a charged perfect fluid
with a polytropic equation of state. The charge density is chosen to be
proportional to the energy density. The study is performed by solving the
Tolman-Oppenheimer-Volkoff (TOV) equation which describes the hydrostatic
equilibrium. We show the dependence of the structure of the spheres for several
characteristic values of the polytropic exponent and for different values of
the charge densities. We also study other physical properties of the charged
spheres, such as the total mass, total charge, radius and sound speed and their
dependence on the polytropic exponent. We find that for the polytropic exponent
\gamma=4/3 the Chandrasekhar mass limit coincides with the Oppenheimer-Volkoff
mass limit. We test the Oppenheimer-Volkoff limit for such compact objects. We
also analyze the Buchdahl limit for these charged polytropic spheres, which
happens in the limit of very high polytropic exponents, i.e., for a stiff
equation of state. It is found that this limit is extremal and it is a
quasiblack hole.


title:
UPMASK: unsupervised photometric membership assignment in stellar
  clusters

abstract:
  We develop a method for membership assignment in stellar clusters using only
photometry and positions. The method, UPMASK, is aimed to be unsupervised, data
driven, model free, and to rely on as few assumptions as possible. It is based
on an iterative process, principal component analysis, clustering algorithm,
and kernel density estimations. Moreover, it is able to take into account
arbitrary error models. An implementation in R was tested on simulated clusters
that covered a broad range of ages, masses, distances, reddenings, and also on
real data of cluster fields. Running UPMASK on simulations showed that it
effectively separates cluster and field populations. The overall spatial
structure and distribution of cluster member stars in the colour-magnitude
diagram were recovered under a broad variety of conditions. For a set of 360
simulations, the resulting true positive rates (a measurement of purity) and
member recovery rates (a measurement of completeness) at the 90% membership
probability level reached high values for a range of open cluster ages
($10^{7.1}-10^{9.5}$ yr), initial masses ($0.5-10\times10^3$M$_{\sun}$) and
heliocentric distances ($0.5-4.0$ kpc). UPMASK was also tested on real data
from the fields of the open cluster Haffner~16 and of the closely projected
clusters Haffner~10 and Czernik~29. These tests showed that even for moderate
variable extinction and cluster superposition, the method yielded useful
cluster membership probabilities and provided some insight into their stellar
contents. The UPMASK implementation will be available at the CRAN archive.


title: Measurement of Excited Hyperons in Photoproduction at CLAS

abstract:
  Measurement results of photoproduced excited hyperon states using the CLAS
detector at Jefferson Lab are shown. The invariant mass distribution of the
Lambda(1405) has recently been shown to be different for each of the three
Sigma pi channels that it decays to, showing that there is prominent
interference between the isospin I=0 and I=1 isospin amplitudes. Measurements
of the differential and total cross sections of the three hyperons
Lambda(1405), Sigma0(1385), and Lambda(1520) are presented and compared.
Prospects of future studies using a 12 GeV beam with the GlueX detector are
briefly given.


title: Strongly Correlated Materials

abstract:
  Strongly correlated materials are profoundly affected by the repulsive
electron-electron interaction. This stands in contrast to many commonly used
materials such as silicon and aluminum, whose properties are comparatively
unaffected by the Coulomb repulsion. Correlated materials often have remarkable
properties and transitions between distinct, competing phases with dramatically
different electronic and magnetic orders. These rich phenomena are fascinating
from the basic science perspective and offer possibilities for technological
applications. This article looks at these materials through the lens of
research performed at Rice University. Topics examined include: Quantum phase
transitions and quantum criticality in "heavy fermion" materials and the iron
pnictide high temperature superconductors; computational ab initio methods to
examine strongly correlated materials and their interface with analytical
theory techniques; layered dichalcogenides as example correlated materials with
rich phases (charge density waves, superconductivity, hard ferromagnetism) that
may be tuned by composition, pressure, and magnetic field; and nanostructure
methods applied to the correlated oxides VO2 and Fe3O4, where metal-insulator
transitions can be manipulated by doping at the nanoscale or driving the system
out of equilibrium. We conclude with a discussion of the exciting prospects for
this class of materials.


title: Mass, Speed, Direction: John Buridan's 14th century concept of momentum

abstract:
  In the 14th century the French thinker John Buridan developed a theory of
motion that bears a strong resemblance to Newtonian momentum. Buridan's ideas
include a quantity of motion which is determined by an object's mass, speed,
and direction; in the absence of resistive effects, this quantity remains with
the object. Buridan's work is an interesting story in the history of physics.
Buridan's insights have value for introducing concepts of inertia and momentum
to physics students.


title:
Spectrum of Weighted Composition Operators. Part III. Essential spectra
  of some disjointness preserving operators on Banach lattices

abstract:
  We describe essential (in particular Fredholm and semi-Fredholm) spectra of
operators on Banach lattices of the form $T=wU$, where $w$ is a central
operator and $U$ is a disjointness preserving operator such that its spectrum
$\sigma(U)$ is a subset of the unit circle.


title:
Mapping Variable Ring Polymer Molecular Dynamics: A Path-Integral Based
  Method for Nonadiabatic Processes

abstract:
  We introduce mapping-variable ring polymer molecular dynamics (MV-RPMD), a
model dynamics for the direct simulation of multi-electron processes. An
extension of the RPMD idea, this method is based on an exact, imaginary time
path-integral representation of the quantum Boltzmann operator using continuous
Cartesian variables for both electronic states and nuclear degrees of freedom.
We demonstrate the accuracy of the MV-RPMD approach in calculations of
real-time, thermal correlation functions for a range of two-state single-mode
model systems with different coupling strengths and asymmetries. Further, we
show that the ensemble of classical trajectories employed in these simulations
preserves the Boltzmann distribution and provides a direct probe into real-time
coupling between electronic state transitions and nuclear dynamics.


title: Lie elements in the group algebra

abstract:
  Given a representation V of a group G, there are two natural ways of defining
a representation of the group algebra k[G] in the external power V^{\wedge m}.
The set L(V) of elements of k[G] for which these two ways give the same result
is a Lie algebra and a representation of G. For the case when G is a symmetric
group and V = C^n, a permutation representation, these spaces L(C^n) are
naturally embedded into one another. We describe L(C^n) for small n and
formulate some questions and conjectures.
  This is a note on research in progress.


title: Progress toward a Soft X-ray Polarimeter

abstract:
  We are developing instrumentation for a telescope design capable of measuring
linear X-ray polarization over a broad-band using conventional spectroscopic
optics. Multilayer-coated mirrors are key to this approach, being used as Bragg
reflectors at the Brewster angle. By laterally grading the multilayer mirrors
and matching to the dispersion of a spectrometer, one may take advantage of
high multilayer reflectivities and achieve modulation factors over 50% over the
entire 0.2-0.8 keV band. We present progress on laboratory work to demonstrate
the capabilities of an existing laterally graded multilayer coated mirror pair.
We also present plans for a suborbital rocket experiment designed to detect a
polarization level of 12-17% for an active galactic nucleus in the 0.1-1.0 keV
band.


title: Local Lorentz-Symmetry Breaking and Gravity

abstract:
  The lagrangian-based Standard-Model Extension framework offers a broad
description of possible gravitational effects from local Lorentz violation. In
this talk, I review the status of the theoretical and phenomenological work in
this area. The extension of previous results in linearized gravity to the
nonlinear regime is discussed.


title: Scale-free primordial cosmology

abstract:
  The large-scale structure of the universe suggests that the physics
underlying its early evolution is scale-free. This was the historic motivation
for the Harrison-Zel'dovich-Peebles spectrum and for inflation. Based on a
hydrodynamical approach, we identify scale-free forms for the background
equation-of-state for both inflationary and cyclic scenarios and use these
forms to derive predictions for the spectral tilt and tensor-to-scalar ratio of
primordial density perturbations. For the case of inflation, we find three
classes of scale-free models with distinct predictions. Including all classes,
we show that scale-free inflation predicts tensor-to-scalar ratio $r >
10^{-4}$. We show that the observationally favored class is theoretically
disfavored because it suffers from an initial conditions problem and the
hydrodynamical form of an unlikeliness problem similar to that identified
recently for certain inflaton potentials. We contrast these results with those
for scale-free cyclic models.


title:
Enumeration of labeled and unlabeled k-gonal and polygonal 2-trees and
  succulents by vertices

abstract:
  We use the theory of \Gamma-species to enumerate k-gonal and polygonal
2-trees with respect to their vertices. We then extend this result to enumerate
"succulents", a tree-like class of graphs which generalize cacti.


title:
SU(N) Representation of Mode Dispersion in a Multimode Optical Fiber:
  Determining Principal Modes for Mode Division Multiplexing

abstract:
  A method is proposed to experimentally determine principal modes for mode
division multiplexing in a multimode optical fiber, i.e., increasing optical
fiber information capacity via higher-order transverse eigenmodes. Principal
modes are a special linear combination of eigenmodes that do not exhibit mode
dispersion up to first order in frequency. This method is based on an SU(N)
representation of mode dispersion whereby the generators of the corresponding
SU(N) Lie algebra, i.e., generalized Gell-Mann matrices, predict higher-order
Stokes parameters which can be used to measure principal modes at the optical
fiber input and output. Applications of the SU(N) representation to decoherence
free subspaces for single photon entanglement in higher-dimensional Hilbert
spaces is discussed.


title:
Overview of the Massive Young Star-Forming Complex Study in Infrared and
  X-ray (MYStIX) Project

abstract:
  MYStIX (Massive Young Star-Forming Complex Study in Infrared and Xray) seeks
to characterize 20 OB-dominated young clusters and their environs at distances
d < 4 kpc using imaging detectors on the Chandra X-ray Observatory, Spitzer
Space Telescope, and the United Kingdom InfraRed Telescope. The observational
goals are to construct catalogs of star-forming complex stellar members with
well-defined criteria, and maps of nebular gas (particularly of hot X-ray
emitting plasma) and dust. A catalog of MYStIX Probable Complex Members (MPCMs)
with several hundred OB stars and > 30, 000 low mass premain sequence is
assembled. This sample and related data products will be used to seek new
empirical constraints on theoretical models of cluster formation and dynamics,
mass segregation, OB star formation, star formation triggering on the periphery
of HII regions, the survivability of protoplanetary disks in HII regions. This
paper give an introduction and overview of the project, covering the data
analysis methodology and application to two star forming regions, NGC 2264 and
the Trifid Nebula.


title:
A Massive Young Star-Forming Complex Study in Infrared and X-ray: X-ray
  Sources in Ten Star Forming Regions

abstract:
  The Massive Young star-forming complex Study in Infrared and X-ray (MYStIX)
uses data from the Chandra X-ray Observatory to identify and characterize the
young stellar populations in twenty Galactic (d < 4 kpc) massive star-forming
regions. Here, the X-ray analysis for Chandra ACIS-I observations of ten of the
MYStIX fields is described, and a catalog of >10,000 X-ray sources is
presented. In comparison to other published Chandra source lists for the same
regions, the number of MYStIX detected faint X-ray sources in a region is often
doubled. While the higher catalog sensitivity increases the chance of false
detections, it also increases the number of matches to infrared stars. X-ray
emitting contaminants include foreground stars, background stars, and
extragalactic sources. The X-ray properties of sources in these classes are
discussed.


title: Computing the Number of Types of Infinite Length

abstract:
  We show that the number of types of sequences of tuples of a fixed length can
be calculated from the number of 1-types and the length of the sequences.
Specifically, if $\kappa \leq \lambda$, then $$\sup_{|A| = \lambda}
|S^\kappa(A)| = (\sup_{|A| = \lambda} |S^1(A)|)^\kappa$$ We show that this
holds for any abstract elementary class with $\lambda$ amalgamation, but it is
new for first order theories when $\kappa$ is infinite. No such calculation is
possible for nonalgebraic types. We introduce a generalization of nonalgebraic
types for which the same upper bound holds.


title: Operations on open book foliations

abstract:
  We study b-arc foliation change and exchange move of open book foliations
which generalize the corresponding operations in braid foliation theory. We
also define a bypass move as an analogue of Honda's bypass attachment
operation.
  As applications, we study how open book foliations change under a
stabilization of the open book. We also generalize Birman-Menasco's
split/composite braid theorem: Closed braid representatives of a split (resp.
composite) link in a certain open book can be converted to a split (resp.
composite) closed braid by applying exchange moves finitely many times.


title: The Wide-Field Near Infrared Data: Optimal Photometry in Crowded Fields

abstract:
  We present JHK infrared data from the UK Infrared Telescope for a subset of
the regions of the MYStIX (Massive Young Star-Forming Complex Study in Infrared
and X-ray) survey. Some of the data were obtained specifically for the MYStIX
project, and some as part of the UKIRT Infrared Deep Sky Survey's Galactic
Plane Survey. In most of these fields crowding is a significant issue for
aperture photometry, and so we have re-extracted the photometry from the
processed images using an optimal extraction technique, and we describe how we
adapt the optimal technique to mitigate the effects of crowding.


title: Impact of cavity spectrum on span in microresonator frequency combs

abstract:
  We experimentally study the factors that limit the span in frequency combs
derived from the crystalline whispering gallery mode resonators. We observe
that cavity dispersion is the key property that governs the parameters of the
combs resulting from cascaded four wave mixing process. Two different regimes
of comb generation are observed depending on the precise cavity dispersion
behavior at the pump wavelength. In addition, the comb generation efficiency is
found to be affected by the crossing of modes of different families. The
influence of Raman lasing is discussed.

categories: physics.optics cond-mat.other nlin.PS quant-ph


title: Detection of Propene in Titan's Stratosphere

abstract:
  The Voyager 1 flyby of Titan in 1980 gave a first glimpse of the chemical
complexity of Titan's atmosphere, detecting many new molecules with the
infrared spectrometer (IRIS). These included propane (C3H8) and propyne
(CH3C2H), while the intermediate-sized C3Hx hydrocarbon (C3H6) was curiously
absent. Using spectra from the Composite Infrared Spectrometer (CIRS) on
Cassini, we show the first positive detection of propene (C3H6) in Titan's
stratosphere (5-sigma significance), finally filling the three-decade gap in
the chemical sequence. We retrieve a vertical abundance profile from 100-250
km, that varies slowly with altitude from ~2 ppbv at 100 km, to ~5 ppbv at 200
km. The abundance of C3H6 is less than both C3H8 and CH3C2H, and we remark on
an emerging paradigm in Titan's hydrocarbon abundances whereby: alkanes >
alkynes > alkenes within the C2Hx and C3Hx chemical families in the lower
stratosphere. More generally, there appears to be much greater ubiquity and
relative abundance of triple-bonded species than double-bonded, likely due to
the greater resistance of triple bonds to photolysis and chemical attack.


title:
A Massive Young Star-Forming Complex Study in Infrared and X-ray:
  Mid-Infrared Observations and Catalogs

abstract:
  Spitzer IRAC observations and stellar photometric catalogs are presented for
the Massive Young Star-Forming Complex Study in the Infrared and X-ray
(MYStIX). MYStIX is a multiwavelength census of young stellar members of twenty
nearby (d < 4 kpc), Galactic, star-forming regions that contain at least one O
star. All regions have data available from the Spitzer Space Telescope,
consisting of GLIMPSE or other published catalogs for eleven regions and
results of our own photometric analysis of archival data for the remaining nine
regions. This paper seeks to construct deep and reliable catalogs of sources
from the Spitzer images. Mid-infrared study of these regions faces challenges
of crowding and high nebulosity. Our new catalogs typically contain fainter
sources than existing Spitzer studies, which improves the match rate to Chandra
X-ray sources that are likely to be young stars, but increases the possibility
of spurious point-source detections, especially peaks in the nebulosity. IRAC
color-color diagrams help distinguish spurious detections of nebular PAH
emission from the infrared excess associated with dusty disks around young
stars. The distributions of sources on the mid-infrared color-magnitude and
color-color diagrams reflect differences between MYStIX regions, including
astrophysical effects such as stellar ages and disk evolution.


title: Bayesian Matching for X-ray and Infrared Sources in the MYStIX Project

abstract:
  Identifying the infrared counterparts of X-ray sources in Galactic Plane
fields such as those of the MYStIX project presents particular difficulties due
to the high density of infrared sources. This high stellar density makes it
inevitable that a large fraction of X-ray positions will have a faint field
star close to them, which standard matching techniques may incorrectly take to
be the counterpart. Instead we use the infrared data to create a model of both
the field star and counterpart magnitude distributions, which we then combine
with a Bayesian technique to yield a probability that any star is the
counterpart of an X-ray source. In our more crowded fields, between 10 and 20%
of counterparts that would be identified on the grounds of being the closest
star to X-ray position within a 99% confidence error circle are instead
identified by the Bayesian technique as field stars. These stars are
preferentially concentrated at faint magnitudes. Equally importantly the
technique also gives a probability that the true counterpart to the X-ray
source falls beneath the magnitude limit of the infrared catalog. In deriving
our method, we place it in the context of other procedures for matching
astronomical catalogs.


title: Observing supernova neutrino light curve in future dark matter detectors

abstract:
  The possibility of observing supernova (SN) neutrinos through the process of
coherent elastic neutrino-nucleus scattering (CENNS) in future ton scale
detectors designed primarily for direct detection of dark matter is
investigated. In particular, we focus on the possibility of distinguishing the
various phases of the SN neutrino emission. The neutrino emission rates from
the recent long term Basel/Darmstadt simulations are used to calculate the
expected event rates. The recent state-of-the-art SN simulations predict closer
fluxes among different neutrino flavors and lower average energies compared to
the earlier simulation models. We find that our estimated total event rates are
typically a factor of two lower than those predicted using older simulation
models. We further find that, with optimistic assumptions on the detector's
time resolution (~ 10 ms) and energy threshold (~ 0.1 keV), the neutrinos
associated with the accretion phase of the SN can in principle be demarcated
out with, for example, a 10-ton Xe detector, although distinguishing the
neutrinos associated with the neutronization burst phase of the explosion would
typically require several tens of ton detectors. We also comment on the
possibility of studying the properties of non-electron flavor neutrinos from
the CENNS of SN neutrinos.


title:
17P/Holmes: Contrast in activity between before and after the 2007
  outburst

abstract:
  A Jupiter-family comet, 17P/Holmes, underwent outbursts in 1892 and 2007. In
particular, the 2007 outburst is known as the greatest outburst over the past
century. However, little is known about the activity before the outburst
because it was unpredicted. In addition, the time evolution of the nuclear
physical status has not been systematically studied. Here we study the activity
of 17P/Holmes before and after the 2007 outburst through optical and
mid-infrared observations. We found that the nucleus highly depleted its
near-surface icy component before but became activated after the 2007 outburst.
Assuming a conventional 1-um-sized grain model, we derived a surface fractional
active area of 0.58% +- 0.14% before the outburst whereas it was enlarged by a
factor of ~50 after the 2007 outburst. We also found that large (>=1 mm)
particles could be dominant in the dust tail observed around aphelion. Based on
the size of the particles, the dust production rate was >=170 kg/s at the
heliocentric distance rh = 4.1 AU, suggesting that the nucleus still held
active status around the aphelion passage. The nucleus color was similar to
that of the dust particles and average for a Jupiter-family comet but different
from most Kuiper Belt objects, implying that the color may be inherent to icy
bodies in the solar system. On the basis of these results, we concluded that
more than 76 m surface materials were blown off by the 2007 outburst.


title: First Results from NuSTAR Observations of Mkn 421

abstract:
  Mkn 421 is a nearby active galactic nucleus dominated at all wavelengths by a
very broad non-thermal continuum thought to arise from a relativistic jet seen
at a small angle to the line of sight. Its spectral energy distribution peaks
in the X-ray and TeV gamma-ray bands, where the energy output is dominated by
cooling of high-energy electrons in the jet. In order to study the electron
distribution and its evolution, we carried out a dedicated multi-wavelength
campaign, including extensive observations by the recently launched highly
sensitive hard X-ray telescope NuSTAR, between December 2012 and May 2013. Here
we present some initial results based on NuSTAR data from January through March
2013, as well as calibration observations conducted in 2012. Although the
observations cover some of the faintest hard X-ray flux states ever observed
for Mkn 421, the sensitivity is high enough to resolve intra-day spectral
variability. We find that in this low state the dominant flux variations are
smooth on timescales of hours, with typical intra-hour variations of less than
5%. We do not find evidence for either a cutoff in the hard X-ray spectrum, or
a rise towards a high-energy component, but rather that at low flux the
spectrum assumes a power law shape with a photon index of approximately 3. The
spectrum is found to harden with increasing brightness.


title:
Modeling of atmospheres of the brightest stars belonging to the Cyg OB2
  association

abstract:
  We present the results of modeling of the spectrum of the brightest stars
belonging to the Cyg OB2 association - #7 (O3If*) and #11 (O5Ifc). #7 is one of
the hottest stars in our Galaxy, while #11 belongs to the spectral class Ofc,
which was recently introduced and yet small in numbers (Walborn et al., 2010).
We determine the physical properties and chemical composition of their
atmosphere using CMFGEN code. The atmosphere of #7 reveals an excess of
nitrogen X(N*)/X(Nsun) = 3.2 and the carbon and oxygen deficiency X(C*)/X(Csun)
= 0.08, X(O*)/X(Osun) = 0.09, while the atmosphere of #11 is enriched with
carbon X(C*)/X(Csun)=1 and silicon X(Si *)/X(Si sun)=2.


title:
Evaluating socio-economic state of a country analyzing airtime credit
  and mobile phone datasets

abstract:
  Reliable statistical information is important to make political decisions on
a sound basis and to help measure the impact of policies. Unfortunately,
statistics offices in developing countries have scarce resources and
statistical censuses are therefore conducted sporadically. Based on mobile
phone communications and history of airtime credit purchases, we estimate the
relative income of individuals, the diversity and inequality of income, and an
indicator for socioeconomic segregation for fine-grained regions of an African
country. Our study shows how to use mobile phone datasets as a starting point
to understand the socio-economic state of a country, which can be especially
useful in countries with few resources to conduct large surveys.


title: The MYStIX InfraRed-Excess Source Catalog

abstract:
  The MYStIX project (Massive Young Star-Forming Complex Study in Infrared and
X-rays) provides a comparative study of 20 Galactic massive star-forming
complexes (d = 0.4 to 3.6 kpc). Probable stellar members in each target complex
are identified using X-ray and/or infrared data via two pathways: (1) X-ray
detections of young/massive stars with coronal activity/strong winds; or (2)
infrared excess (IRE) selection of young stellar objects (YSOs) with
circumstellar disks and/or protostellar envelopes. We present the methodology
for the second pathway, using Spitzer/IRAC, 2MASS, and UKIRT imaging and
photometry. Although IRE selection of YSOs is welltrodden territory, MYStIX
presents unique challenges. We combine IR spectral energy distribution (SED)
fitting with IR color cuts and spatial clustering analysis to identify IRE
sources and isolate probable YSO members in each MYStIX target field from the
myriad types of contaminating sources that can resemble YSOs: extragalactic
sources, evolved stars, nebular knots, and even unassociated
foreground/background YSOs. Applying our methodology consistently across 18 of
the target complexes, we produce the MYStIX IRE Source (MIRES) Catalog
comprising 20,719 sources, including 8686 probable stellar members of the
MYStIX target complexes. We also classify the SEDs of 9365 IR counterparts to
MYStIX X-ray sources to assist the first pathway, the identification of X-ray
detected stellar members. The MIRES catalog provides a foundation for follow-up
studies of diverse phenomena related to massive star cluster formation,
including protostellar outflows, circumstellar disks, and sequential star
formation triggered by massive star feedback processes.


title:
Non-negatively constrained least squares and parameter choice by the
  residual periodogram for the inversion of electrochemical impedance
  spectroscopy

abstract:
  The inverse problem associated with electrochemical impedance spectroscopy
requiring the solution of a Fredholm integral equation of the first kind is
considered. If the underlying physical model is not clearly determined, the
inverse problem needs to be solved using a regularized linear least squares
problem that is obtained from the discretization of the integral equation. For
this system, it is shown that the model error can be made negligible by a
change of variables and by extending the effective range of quadrature. This
change of variables serves as a right preconditioner that significantly
improves the condition of the system. Still, to obtain feasible solutions the
additional constraint of non-negativity is required. Simulations with
artificial, but realistic, data demonstrate that the use of non-negatively
constrained least squares with a smoothing norm provides higher quality
solutions than those obtained without the non-negative constraint. Using
higher-order smoothing norms also reduces the error in the solutions. The
L-curve and residual periodogram parameter choice criteria, which are used for
parameter choice with regularized linear least squares, are successfully
adapted to be used for the non-negatively constrained Tikhonov least squares
problem. Although these results have been verified within the context of the
analysis of electrochemical impedance spectroscopy, there is no reason to
suppose that they would not be relevant within the broader framework of solving
Fredholm integral equations for other applications.


title:
Restoring the privacy and confidentiality of users over Mobile
  collaborative learning (MCL) environment

abstract:
  Mobile collaborative learning (MCL) is extensively recognized field all over
the world. It demonstrates the cerebral approach combining the several
technology to handle the problem of learning. MCL motivates the social and
educational activities for creating healthier environment. To advance and
promote the baseline of MCL, different frameworks have been introduced for MCL.
From other side, there is no highly acceptable security mechanism has been
implemented to protect MCL environment. This paper introduces the issue of
rogue DHCP server, which highly affects the performance of users who
communicate with each other through MCL. The rogue DHCP is unofficial server
that gives incorrect IP address to user in order to use the legal sources of
different servers by sniffing the traffic. The contribution focuses to maintain
the privacy of users and enhances the confidentiality. The paper introduces
multi-frame signature-cum anomaly-based intrusion detection systems (MSAIDS)
supported with innovative algorithms, modification in the existing rules of IDS
and use of mathematical model. The major objectives of research are to identify
the malicious attacks created by rogue DHCP server. This innovative mechanism
emphasizes the security for users in order to communicate freely. It also
protects network from illegitimate involvement of intruders. Finally, the paper
validates the mechanism using three types of simulations: testbed, discrete
simulation in C++ and ns2. On the basis of findings, the efficiency of proposed
mechanism has been compared with other well-known techniques.


title:
Identifying Young Stars in Massive Star-Forming Regions for the MYStIX
  Project

abstract:
  The Massive Young star-forming Complex Study in Infrared and X-rays (MYStIX)
project requires samples of young stars that are likely members of 20 nearby
Galactic massive star-forming regions. Membership is inferred from statistical
classification of X-ray sources, from detection of a robust infrared excess
that is best explained by circumstellar dust in a disk or infalling envelope,
and from published spectral types that are unlikely to be found among field
stars. We present the MYStIX membership lists here, and describe in detail the
statistical classification of X-ray sources via a \Naive Bayes Classi


title: A fully automatic problem solver with human-style output

abstract:
  This paper describes a program that solves elementary mathematical problems,
mostly in metric space theory, and presents solutions that are hard to
distinguish from solutions that might be written by human mathematicians. The
program is part of a more general project, which we also discuss.


title: Quantum Process Tomography of a Molmer-Sorensen Interaction

abstract:
  We report the quantum process tomography of a M$\o$lmer-S$\o$rensen
entangling gate. The tomographic protocol relies on a single discriminatory
transition, exploiting excess micromotion in the trap to realize all operations
required to prepare all input states and analyze all output states. Using a
master-slave diode lasers setup, we demonstrate a two-qubit entangling gate,
with a fidelity of Bell state production of 0.985(10). We characterize its
$\chi$-process matrix, the simplest for an entanglement gate on a
separable-states basis, and we observe that the dominant source of error is
accurately modelled by a quantum depolarization channel.


title:
Bandstructure and mobility variations in p-type Silicon nanowires under
  electrostatic gate field

abstract:
  The sp3d5s*-spin-orbit-coupled atomistic tight-binding (TB) model is used for
the electronic structure calculation of Si nanowires (NWs), self consistently
coupled to a 2D Poisson equation, solved in the cross section of the NW. Upon
convergence, the linearized Boltzmann transport theory is employed for the
mobility calculation, including carrier scattering by phonons and surface
roughness. As the channel is driven into inversion, for [111] and [110] NW
devices of diameters D>10nm the curvature of the bandstructure increases and
the hole effective mass becomes lighter, resulting in a approx. 50% mobility
increase. Such improvement is large enough to compensate for the detrimental
effect of surface roughness scattering. The effect is very similar to the
bandstructure variations and mobility improvement observed under geometric
confinement, however, in this case confinement is caused by electrostatic
gating. We provide explanations for this behavior based on features of the
heavy-hole band. This effect could be exploited in the design of p-type NW
devices. We note, finally, that the 'apparent' mobility of low dimensional
short channel transistors is always lower than the intrinsic channel diffusive
mobility due to the detrimental influence of the so called 'ballistic'
mobility.


title:
Automatic energy saving (AES) modelto boost ubiquitous wireless sensor
  networks (WSNs)

abstract:
  We deploy BT node (sensor) that offers passive and active sensing capability
to save energy. BT node works in passive mode for outdoor communication and
active for indoor communication. The BT node is supported with novel automatic
energy saving (AES) mathematical model to decide either modes. It provides
robust and faster communication with less energy consumption. To validate this
approach, network simulator-2 (ns2) simulation is used to simulate the behavior
of network with the supporting mathematical model. The main objective of this
research is to remotely access different types of servers, laptops, desktops
and other static and moving objects. This prototype is initially deployed to
control MSCS [13] & [14] from remote place through mobile devices. The
prototype can further be enhanced to handle several objects simultaneously
consuming less energy and resources.


title:
Large time decay properties of solutions to a viscous Boussinesq system
  in a half space

abstract:
  We consider the long time behavior of weak and strong solutions of the
n-dimensional viscous Boussinesq system in the half space, with $n\geq3$ . The
$L^r(R^n_+)$-asymptotics of strong solutions and their first three derivatives,
with $1\leq r\leq\infty$, are derived combining $L^q-L^r$ estimates and
properties of the fractional powers of the Stokes operator. For the
$L^\infty-$asymptotics of the second order derivatives the unboundedness of the
projection operator $P: L^\infty(R^n_+)\rightarrow L^\infty_\sigma(R^n_+)$ is
dealt by an appropriate decomposition of the nonlinear term.


title:
Non-negatively constrained least squares and parameter choice by the
  residual periodogram for the inversion of dielectric relaxation spectra:
  Supplementary Materials

abstract:
  This document contains supplementary derivations and discussions not provided
in the submitted paper arXiv:1309.4498 with the same title. Additional results
for the NCP and L-Curve comparisons with higher noise levels are given.


title: Faster Fair Solution for the Reader-Writer Problem

abstract: A fast fair solution for Reader-Writer Problem is presented.


title:
Introduction of 6th Generation Smart Phone combining the features of
  both Apple and Android smart phone

abstract:
  In this paper, we present our novel contribution methodology based on the
results of case study that has been implemented in our research environment to
test with new technique the usability of both intelligent Android and Apple
phones. This analysis of the case study stands for features similar to
applications, operating system, hardware and software structure, battery life,
and online based websites. Multiple interrogations were applied to collect user
answers ongoing features. Users directly react by responding based on their
daily used product experience. Consequently, the estimation is based on the
data that has been unregistered from the user. The most recent results will end
up by introducing a combination of ideal features on both products to build a
wonderful extended product in the future.


title:
Spin polarization oscillations without spin precession: spin-orbit
  entangled resonances in quasi-one-dimensional spin transport

abstract:
  Resonant behavior involving spin-orbit entangled states occurs for spin
transport along a narrow channel defined in a two-dimensional electron gas,
including an apparent rapid relaxation of the spin polarization for special
values of the channel width and applied magnetic field (so-called ballistic
spin resonance). A fully quantum mechanical theory for transport through
multiple subbands of the one-dimensional system provides the dependence of the
spin transport on the applied magnetic field and channel width, including a
resonant depolarization of spins when the Zeeman energy matches the subband
energy splittings and a spin texture transverse to the magnetic field. The
resonance phenomenon is robust to disorder.


title:
A Littlewood-Richardson rule for the MacDonald inner product and
  bimodules over wreath products

abstract:
  We prove a Littlewood-Richardson type formula for
$(s_{\lambda/\mu},s_{\nu/\kappa})_{t^k,t}$, the pairing of two skew Schur
functions in the MacDonald inner product at $q = t^k$ for positive integers
$k$. This pairing counts graded decomposition numbers in the representation
theory of wreath products of the algebra $C[x]/x^k$ and symmetric groups.


title: Robust Heterogeneous Network to Support Multitasking

abstract:
  Due to emerging technology, efficient multitasking approach is highly
demanded. But it is hard to accomplish in heterogeneous wireless networks,
where diverse networks have dissimilar geometric features in service and
traffic models. Multitasking loss examination based on Markov chain becomes
inflexible in these networks owing to rigorous computations is obligatory. This
paper emphases on the performance of heterogeneous wireless networks based on
multitasking. A method based on multitasking of the interrelated traffic is
used to attain an approximate performance in heterogeneous wireless networks
with congested traffic. The accuracy of the robust heterogeneous network with
multitasking is verified by using ns2 simulations.


title: Localization for controlled random walks and martingales

abstract:
  We consider controlled random walks that are martingales with uniformly
bounded increments and nontrivial jump probabilities and show that such walks
can be constructed so that P(S_n^u=0) decays at polynomial rate n^{-\alpha}
where \alpha>0 can be arbitrarily small. We also show, by means of a general
delocalization lemma for martingales, which is of independent interest, that
slower than polynomial decay is not possible.


title: Distributed Detection in Tree Topologies with Byzantines

abstract:
  In this paper, we consider the problem of distributed detection in tree
topologies in the presence of Byzantines. The expression for minimum attacking
power required by the Byzantines to blind the fusion center (FC) is obtained.
More specifically, we show that when more than a certain fraction of individual
node decisions are falsified, the decision fusion scheme becomes completely
incapable. We obtain closed form expressions for the optimal attacking
strategies that minimize the detection error exponent at the FC. We also look
at the possible counter-measures from the FC's perspective to protect the
network from these Byzantines. We formulate the robust topology design problem
as a bi-level program and provide an efficient algorithm to solve it. We also
provide some numerical results to gain insights into the solution.


title:
On the Dimension of Matrix Representations of Finitely Generated Torsion
  Free Nilpotent Groups

abstract:
  It is well known that any polycyclic group, and hence any finitely generated
nilpotent group, can be embedded into $GL_{n}(\mathbb{Z})$ for an appropriate
$n\in \mathbb{N}$; that is, each element in the group has a unique matrix
representation. An algorithm to determine this embedding was presented in
Nickel. In this paper, we determine the complexity of the crux of the algorithm
and the dimension of the matrices produced as well as provide a modification of
the algorithm presented by Nickel.


title:
Dihadron Correlations Relative to the Event Plane in 200 GeV Au+Au
  Collisions from STAR

abstract:
  Dihadron correlations with a high-pt trigger particle are analyzed by STAR
relative to the event plane in Au+Au collisions at 200 GeV (arXiv:1010.0690v1).
The elliptic and quadrangular flow anisotropies are subtracted. The remaining
dihadron correlation signals are found to be composed of a near-side peak,
which is separated into jet-like and "ridge"-like components, and an away-side
correlation structure. The ridge-like structure is found to decrease with the
trigger particle azimuthal angle relative to the event plane from in-plane to
out-of-plane. The away-side structure is found to evolve from single-peak for
in-plane triggers to double-peak for out-of-plane triggers. Is the dihadron
correlation signal just a manifestation of the triangular and higher-order
harmonic flows? This talk addresses this question, exploring the answers using
limiting-case assumptions, and discusses the implications of the data regarding
the ridge and the double-peak structure.


title: Strictly singular operators in Tsirelson like spaces

abstract:
  For each $n \in \mathbb{N}$ a Banach space $\mathfrak{X}_{0,1}^n$ is
constructed is having the property that every normalized weakly null sequence
generates either a $c_0$ or $\ell_1$ spreading models and every infinite
dimensional subspace has weakly null sequences generating both $c_0$ and
$\ell_1$ spreading models. The space $\mathfrak{X}_{0,1}^n$ is also
quasiminimal and for every infinite dimensional closed subspace $Y$ of
$\mathfrak{X}_{0,1}^n$, for every $S_1,S_2,\ldots,S_{n+1}$ strictly singular
operators on $Y$, the operator $S_1S_2\cdots S_{n+1}$ is compact. Moreover, for
every subspace $Y$ as above, there exist $S_1,S_2,\ldots,S_n$ strictly singular
operators on $Y$, such that the operator $S_1S_2\cdots S_n$ is non-compact.


title: On Beilinson's equivalence for $p$-adic cohomology

abstract:
  In this short note, we show a p-adic analogue of Beilinson's equivalence
comparing two derived categories: the derived category of holonomic modules and
derived category of modules whose cohomologies are holonomic.


title: On generalized Ramsey numbers for 3-uniform hypergraphs

abstract:
  The well-known Ramsey number $r(t,u)$ is the smallest integer $n$ such that
every $K_t$-free graph of order $n$ contains an independent set of size $u$. In
other words, it contains a subset of $u$ vertices with no $K_2$. Erd{\H o}s and
Rogers introduced a more general problem replacing $K_2$ by $K_s$ for $2\le
s<t$. Extending the problem of determining Ramsey numbers they defined the
numbers $$ f_{s,t}(n)=\min \big{\{} \max \{|W| : W\subseteq V(G) \text{and}
G[W] \text{contains no} K_s\}\big{\}}, $$ where the minimum is taken over all
$K_t$-free graphs $G$ of order $n$. In this note, we study an analogous
function $f_{s,t}^{(3)}(n)$ for 3-uniform hypergraphs. In particular, we show
that there are constants $c_1$ and $c_2$ depending only on $s$ such that $$
c_1(\log n)^{1/4} \left(\frac{\log\log n}{\log\log\log n}\right)^{1/2} < f_{s,
s+1}^{(3)}(n) < c_2 \log n. $$


title: Decision and Search in Non-abelian Cramer Shoup Public Key Cryptosystem

abstract:
  A method for non-abelian Cramer-Shoup cryptosystem is presented. The role of
decision and search is explored, and the platform of solvable/polycyclic group
is suggested. In the process we review recent progress in non-abelian
cryptography and post some open problems that naturally arise from this path of
research.


title: On directed versions of the Corr\'adi-Hajnal Corollary

abstract:
  For $k \in \mathbb N$, Corr\'adi and Hajnal proved that every graph $G$ on
$3k$ vertices with minimum degree $\delta(G) \ge 2k$ has a $C_3$-factor, i.e.,
a partitioning of the vertex set so that each part induces the 3-cycle $C_3$.
Wang proved that every directed graph $\overrightarrow G$ on $3k$ vertices with
minimum total degree $\delta_t(\overrightarrow G):=\min_{v\in
V}(deg^-(v)+deg^+(v)) \ge 3(3k-1)/2$ has a $\overrightarrow C_3$-factor, where
$\overrightarrow C_3$ is the directed 3-cycle. The degree bound in Wang's
result is tight. However, our main result implies that for all integers $a \ge
1$ and $b \ge 0$ with $a+b=k$, every directed graph $\overrightarrow G$ on $3k$
vertices with minimum total degree $\delta_t(\overrightarrow G)\ge 4k-1$ has a
factor consisting of $a$ copies of $\overrightarrow T_3$ and $b$ copies of
$\overrightarrow C_3$, where $\overrightarrow T_3$ is the transitive tournament
on three vertices. In particular, using $b=0$, there is a $\overrightarrow
T_3$-factor of $\overrightarrow G $, and using $a=1$, it is possible to obtain
a $\overrightarrow C_3$-factor of $\overrightarrow G$ by reversing just one
edge of $\overrightarrow G$. All these results are phrased and proved more
generally in terms of undirected multigraphs.
  We conjecture that every directed graph $\overrightarrow G$ on $3k$ vertices
with minimum semidegree $\delta_0(\overrightarrow G):=\min_{v\in
V}\min(deg^-(v),deg^+(v)) \ge 2k$ has a $\overrightarrow C_3$-factor, and prove
that this is asymptotically correct.


title: On generalized Ramsey numbers of Erd\H{o}s and Rogers

abstract:
  Extending the concept of Ramsey numbers, Erd{\H o}s and Rogers introduced the
following function. For given integers $2\le s<t$ let $$ f_{s,t}(n)=\min \{\max
\{|W| : W\subseteq V(G) {and} G[W] {contains no} K_s\} \}, $$ where the minimum
is taken over all $K_t$-free graphs $G$ of order $n$. In this paper, we show
that for every $s\ge 3$ there exist constants $c_1=c_1(s)$ and $c_2=c_2(s)$
such that $f_{s,s+1}(n) \le c_1 (\log n)^{c_2} \sqrt{n}$. This result is best
possible up to a polylogarithmic factor. We also show for all $t-2 \geq s \geq
4$, there exists a constant $c_3$ such that $f_{s,t}(n) \le c_3 \sqrt{n}$. In
doing so, we partially answer a question of Erd\H{o}s by showing that
$\lim_{n\to \infty} \frac{f_{s+1,s+2}(n)}{f_{s,s+2}(n)}=\infty$ for any $s\ge
4$.


title:
Residual Amplitude Modulation in Interferometric Gravitational Wave
  Detectors

abstract:
  The effects of residual amplitude modulation (RAM) in laser interferometers
using heterodyne sensing can be substantial and difficult to mitigate. In this
work, we analyze the effects of RAM on a complex laser interferometer used for
gravitational wave detection. The RAM introduces unwanted offsets in the cavity
length signals and thereby shifts the operating point of the optical cavities
from the nominal point via feedback control. This shift causes variations in
the sensing matrix, and leads to degradation in the performance of the
precision noise subtraction scheme of the multiple-degree-of-freedom control
system. In addition, such detuned optical cavities produce an opto-mechanical
spring, which also varies the sensing matrix. We use our simulations to derive
requirements on RAM for the Advanced LIGO detectors, and show that the RAM
expected in Advanced LIGO will not limit its sensitivity.


title:
Holography, Entanglement Entropy, and Conformal Field Theories with
  Boundaries or Defects

abstract:
  We study entanglement entropy (EE) in conformal field theories (CFTs) in
Minkowski space with a planar boundary or with a planar defect of any
codimension. In any such boundary CFT (BCFT) or defect CFT (DCFT), we consider
the reduced density matrix and associated EE obtained by tracing over the
degrees of freedom outside of a (hemi-)sphere centered on the boundary or
defect. Following Casini, Huerta, and Myers, we map the reduced density matrix
to a thermal density matrix of the same theory on hyperbolic space. The EE maps
to the thermal entropy of the theory on hyperbolic space. For BCFTs and DCFTs
dual holographically to Einstein gravity theories, the thermal entropy is
equivalent to the Bekenstein-Hawking entropy of a hyperbolic black brane. We
show that the horizon of the hyperbolic black brane coincides with the minimal
area surface used in Ryu and Takayanagi's conjecture for the holographic
calculation of EE. We thus prove their conjecture in these cases. We use our
results to compute the R\'enyi entropies and EE in DCFTs in which the defect
corresponds to a probe brane in a holographic dual.


title:
Optical conductivity spectra of the rattling phonons and charge carriers
  in type-VIII clathrate Ba$_8$Ga$_{16}$Sn$_{30}$

abstract:
  We have investigated optical conductivity spectra of $n$- and $p$-type
Ba$_8$Ga $_{16}$Sn$_{30}$ ($\alpha$-BGS) with type-VIII clathrate structure, at
temperatures from 296\,K down to 6\,K with a terahertz time-domain spectrometer
(0.2\,-\,2.5\,THz). The continuous spectra contributed from charge carriers are
dispersive in this frequency range and also temperature- and carrier
type-dependent. The Drude-Smith model taking multiple-scatterings of charge
carriers into account well reproduces those data. The relaxation rate of the
$n$-type carriers decreases more sharply than that in the $p$-type material,
suggesting that a stronger electron-phonon interaction may exist in the
$n$-type than in the $p$-type. On the other hand, the localized infrared-active
modes observed at 1.3\,THz and 1.7\,THz, identified as the rattling phonons of
the Ba$^{2+}$ ion's quasi-on-center vibrations, become soft and broad
significantly with decreasing temperature as well as observed in type-I BGS and
BGG (Ba$_8$Ga$_{16}$Ge$_{30}$) clathrates. The softening in the $n$-type is
smaller by about 30% than in the $p$-type, whereas the linewidth brodening is
almost the same independently on the carrier type. The difference in the
softening is discussed with a scenario where the interaction of rattling
phonons with carriers can modify the anharmonic potential of the guest ions.
The anomalous broadening at low temepratures is also discussed by the
impurity-scattering model presented for a rattling-phonon system strongly
hybridized with acoustic cage phonons.


title:
Pseudosymmetric bias and correct estimation of Coulomb/confinement
  energy for unintentional quantum dot in channel of metal-oxide-semiconductor
  field-effect transistor

abstract:
  We describe a measurement method that enables the correct estimation of the
charging energy of an unintentional quantum dot (QD) in the channel of a
metal-oxide-semiconductor field-effect transistor (MOSFET). If the channel has
a dominant QD with a large charging energy and an array of stray QDs with much
weaker charging, this method eliminates the additional voltage drops due to
stray QDs by regarding the stray QDs as series resistors. We apply this method
to a short-channel MOSFET and find that the charging energy of the dominant QD
can indeed be smaller than the size of the Coulomb diamond.


title: Holography for a small world

abstract:
  The holographic principle asserts that the complete description of the
interior of a sphere is a theory which not only lives on the surface of the
sphere, but also has A/4 binary degrees of freedom. In this context we revisit
the question of whether AdS/CFT is fully holographic. We construct states which
are localized deep in the interior yet are encoded on short scales in the CFT,
seemingly in conflict with the UV/IR prescription. We make a proposal to
address the more basic question of which CFT states are sufficient to describe
physics within a certain region of the bulk.


title: Degeneracy between Abelian and Non-Abelian Strings

abstract:
  In a model that supports both Abelian (Abrikosov-Nielsen-Olesen) and
non-Abelian strings we analyze the parameter space to find examples in which
these strings not only coexist but are degenerate in tension. We prove that
both solutions are locally stable, i.e there are no negative modes in the
string background. The tension degeneracy is achieved at the classical level
and is expected to be lifted by quantum corrections. The set up of the model,
analogous to that of Witten's superconducting cosmic strings, had been extended
to include non-Abelian strings.


title:
Prediction of charmoniumlike structures in the hidden-charm di-eta
  decays of higher charmonia

abstract:
  Considering the situation that a single chiral partilce, $\eta$, is initially
emitted, we study the hidden-charm di-eta decays of charmoniumlike state
$Y(4660)$ and the predicted charmonium $\psi(4790)$, i.e., $Y(4660)/\psi(4790)
\to J/\psi\eta\eta$ through the inetermediates,
$\eta\left[D^{(*)}\bar{D}^{(*)}\right]$ and/or $\eta\
\left[D_s^{+(*)}{D}_s^{-(*)}\right]$, and answer to the important question
whether there exist isoscalar charmoniumlike structures in the
$D^{(*)}\bar{D}^{(*)}$ and/or $D_s^{+(*)}{D}_s^{-(*)}$ channels. Our results
predict that there will be enhancement structures near $D\bar{D}^*$,
$D^*\bar{D}^*$ and $D_s\bar{D}_s^*$ thresholds for $Y(4660)$ and near
$D^*\bar{D}^*$, $D_s\bar{D}_s^*$ and $D_s^*\bar{D}_s^*$ thresholds for
$\psi(4790)$ in the $M_{\mathrm{max}}({J/\psi \eta})$ distributions of
$Y(4660)/\psi(4790) \to \eta \eta J/\psi$, respectively. These peaks are
accessible at future experiments, especially BESIII, Belle, BaBar and
forthcoming BelleII.


title:
Matter Couplings which are Compatible with a Fundamental Theory of
  Physics

abstract:
  A criterion to seek for compatibility of any given matter coupling with a
fundamental theory of physics - assumed here to be the string theory - is
developed. We call this criterion as"`compatibility check", and apply it to
test different kinds of matter coupling which are familiar in cosmological
scenarios. The so called "chameleon effect" - useful to overcome the stringent
constraints on additional non gravitational interactions - is reviewed by
relaxing several assumptions which are commonly found in the bibliography in
order to explore the chameleon behavior of self-interacting scalar fields.
Although the results of this study are far from being conclusive, these (i)
suggest that matter couplings other than the exponential (dilaton) are very
unlikely to arise in a cosmological setup, and (ii) pose reasonable doubts on
the validity of the chameleon picture as we know it.


title:
Suppression of electron spin decoherence of the diamond NV center by a
  transverse magnetic field

abstract:
  We demonstrate that the spin decoherence of nitrogen vacancy (NV) centers in
diamond can be suppressed by a transverse magnetic field if the electron spin
bath is the primary decoherence source. The NV spin coherence, created in "a
decoherence-free subspace" is protected by the transverse component of the
zero-field splitting, increasing the spin-coherence time about twofold. The
decoherence due to the electron spin bath is also suppressed at magnetic fields
stronger than ~25 gauss when applied parallel to the NV symmetry axis. Our
method can be used to extend the spin-coherence time of similar spin systems
for applications in quantum computing, field sensing, and other metrologies.


title: Power Optimization for Network Localization

abstract:
  Reliable and accurate localization of mobile objects is essential for many
applications in wireless networks. In range-based localization, the position of
the object can be inferred using the distance measurements from wireless
signals exchanged with active objects or reflected by passive ones. Power
allocation for ranging signals is important since it affects not only network
lifetime and throughput but also localization accuracy. In this paper, we
establish a unifying optimization framework for power allocation in both active
and passive localization networks. In particular, we first determine the
functional properties of the localization accuracy metric, which enable us to
transform the power allocation problems into second-order cone programs
(SOCPs). We then propose the robust counterparts of the problems in the
presence of parameter uncertainty and develop asymptotically optimal and
efficient near-optimal SOCP-based algorithms. Our simulation results validate
the efficiency and robustness of the proposed algorithms.


title: Additional symmetry of the modified extended Toda hierarchy

abstract:
  In this paper, one new integrable modified extended Toda hierarchy(METH) is
constructed with the help of two logarithmic Lax operators. With this
modification, the interpolated spatial flow is added to make all flows
complete. To show more integrable properties of the METH, the bi-Hamiltonian
structure and tau symmetry of the METH will be given. The additional symmetry
flows of this new hierarchy are presented. These flows form an infinite
dimensional Lie algebra of Block type.


title: Chiral Perturbation Theory for All-Staggered Heavy-Light Mesons

abstract:
  In highly improved staggered quark (HISQ) simulations by the HPQCD, MILC, and
Fermilab Lattice collaborations, both the light quarks and the charm quark are
staggered. We extend chiral perturbation theory for staggered quarks to include
such all-staggered heavy-light mesons. We assume that the heavy quark action is
sufficiently improved that we may take $a m_Q <<1$ (where $m_Q$ is the heavy
quark mass), but also that $m_Q>>\Lambda_{QCD}$ so that a continuum heavy quark
expansion is appropriate. We develop this effective chiral theory through
next-to-leading order, and use it to study the pattern of taste splittings in
the heavy-light meson and to compute the leptonic decay constant of the
heavy-light meson to one-loop in the chiral expansion.


title: Sufficiency of simplex inequalities

abstract:
  Let z_0,...,z_n be the (n-1)-dimensional volumes of facets of an n-simplex.
Then we have the simplex inequalities: z_p < z_0+...+\check{z}_p+...+z_n (0 =<
p =< n), generalizations of triangle inequalities. Conversely, suppose that
numbers z_0,...,z_n > 0 satisfy these inequalities. Does there exist an
n-simplex the volumes of whose facets are them? Kakeya solved this problem
affirmatively in the case n = 3 and conjectured that the assertion is
affirmative also for all n >= 4. We prove that his conjecture is affirmative.
To do this, we define three kinds of spaces of loops associated to n-simplices
and study relations among them systematically. In particular, we show that the
space of edge loops corresponds to the space of facet loops bijectively under a
certain condition of positivity.


title: General Clique Percolation in Network Evolution

abstract:
  We introduce a general $(k,l)$ clique community, which consists of adjacent
$k$-cliques sharing at least $l$ vertices with $k-1 \ge l \ge 1$. The emergence
of a giant $(k,l)$ clique community indicates a $(k,l)$ clique percolation,
which is studied by the largest size gap $\Delta$ of the largest clique
community during network evolution and the corresponding evolution step $T_c$.
For a clique percolation, the averages of $\Delta$ and $T_c$ and the
root-mean-squares of their fluctuations have power law finite-size effects
whose exponents are related to the critical exponents. The fluctuation
distribution functions of $\Delta$ and $T_c$ follow a finite-size scaling form.
In the evolution of the Erd\H{o}s-R\'enyi network, there are a series of
$(k,l)$ clique percolation with
$(k,l)=(2,1),(3,1),(3,2),(4,1),(4,2),(5,1),(4,3)$, and so on. The critical
exponents of clique percolation depend on $l$, but are independent of $k$. The
universality class of a $(k,l)$ clique percolation is characterized alone by
$l$.


title: Nonlocal Modeling in High-Velocity Impact Failure of 6061-T6 Aluminum

abstract:
  In this paper, we present numerical simulations with local and nonlocal
models under dynamic loading conditions. We show that for finite element (FE)
computations of high-velocity, impact problems with softening material models
will result in spurious post-bifurcation mesh dependency solutions. To
alleviate numerical instability associated within the post-bifurcation regime,
a characteristic length scale was added to the constitutive relations based on
calibration of the series of different notch specimen tests. This work aims to
assess the practical relevance of the modified model to yield mesh independent
results in the numerical simulations of high-velocity impact problems. To this
end, we consider the problem of a rigid projectile moving at a range of
velocities between 89-107 m/s, colliding against a 6061-T6 Aluminum disk. A
material model embedded with a characteristic length scale in the manner
proposed by Pijaudier-Cabot and Bazant (1987), but in the context of concrete
damage, was utilized to describe the damage response of the disk. The numerical
result shows that the addition of a characteristic length scale to the
constitutive model does eliminate the pathological mesh dependency and shows
excellent agreements between numerical and experimental results. Furthermore,
the application of a nonlocal model for higher strain rate behavior shows the
ability of the model to address intense localized deformations, irreversible
flow, softening, and final failure.


title: Chiral condensate from the Banks-Casher relation

abstract:
  We report on our ongoing project of determining the chiral condensate of
two-flavor QCD from the Banks-Casher relation. We compute the mode number of
the O(a)-improved Wilson-Dirac operator for several values of \Lambda, and we
discuss different fitting strategies to extract the chiral condensate from its
mass and \Lambda dependence. Our preliminary results haven been obtained at two
different lattice spacings by using CLS-configurations.


title: Regularity and linearity defect of modules over local rings

abstract:
  Given a finitely generated module $M$ over a commutative local ring (or a
standard graded $k$-algebra) $(R,\m,k) $ we detect its complexity in terms of
numerical invariants coming from suitable $\m$-stable filtrations $\mathbb{M}$
on $M$. We study the Castelnuovo-Mumford regularity of $gr_{\mathbb{M}}(M) $
and the linearity defect of $M,$ denoted $\ld_R(M),$ through a deep
investigation based on the theory of standard bases. If $M$ is a graded
$R$-module, then $\reg_R(gr_{\mathbb{M}}(M)) <\infty$ implies
$\reg_R(M)<\infty$ and the converse holds provided $M$ is of homogenous type.
An analogous result can be proved in the local case in terms of the linearity
defect. Motivated by a positive answer in the graded case, we present for local
rings a partial answer to a question raised by Herzog and Iyengar of whether
$\ld_R(k)<\infty$ implies $R$ is Koszul.


title: The pivotal cover and Frobenius-Schur indicators

abstract:
  In this paper, we introduce the notion of the pivotal cover
$\mathcal{C}^{\mathsf{piv}}$ of a left rigid monoidal category $\mathcal{C}$ to
develop a theoretical foundation for the theory of Frobenius-Schur (FS)
indicators in "non-pivotal" settings. For an object $\mathbf{V} \in
\mathcal{C}^{\mathsf{piv}}$, the $(n, r)$-th FS indicator $\nu_{n,
r}(\mathbf{V})$ is defined by generalizing that of an object of a pivotal
monoidal category. This notion gives a categorical viewpoint to some recent
results on generalizations of FS indicators.
  Based on our framework, we also study the FS indicators of the "adjoint
object" in a finite tensor category, which can be considered as a
generalization of the adjoint representation of a Hopf algebra. The indicators
of this object closely relate to the space of endomorphisms of the iterated
tensor product functor.


title:
Local sheet conductivity and sheet current density mapping using a
  single scanning voltage probe

abstract:
  We demonstrate how a single scanning voltage probe can be used to map the
local conductivity and current density in a thin film with no a priori
knowledge of the geometry of the electrical contacts. With state-of-the-art
scanning voltage probes, under appropriate conditions such mapping should be
possible down to nanometer scales. The technique requires two non-colinear
voltage scans. When only one voltage map is available, determination of the
conductivity is not possible because the solution to the governing equation is
not unique. The only restriction on the technique is that the sheet
conductivity is a local function of position.


title: Testing for CPT Violation in B0_s Semileptonic Decays

abstract:
  A D0 analysis measuring the charge asymmetry Ab_sl of like-sign dimuon events
due to semileptonic b-hadron decays at the Fermilab Tevatron Collider has shown
indications of possible anomalous CP violation in the mixing of neutral B
mesons. This result has been used to extract the first senstivity to CPT
violation in the B0_s system. A procedure to explore further this anomaly by
specifically measuring the semileptonic charge asymmetry, as_sl, in B0_s decays
is described, as well as how a variant of this analysis can be used to explore
a larger set of CPT-violating parameters in the B0_s system for the first time.


title: On Totally Positive Matrices and Geometric Incidences

abstract:
  A matrix is called totally positive if every minor of it is positive. Such
matrices are well studied and have numerous applications in Mathematics and
Computer Science. We study how many times the value of a minor can repeat in a
totally positive matrix and show interesting connections with incidence
problems in combinatorial geometry. We prove that the maximum possible number
of repeated $d \times d$-minors in a $d \times n$ totally-positive matrix is
$O(n^{d-\frac{d}{d+1}})$. For the case $d=2$ we also show that our bound is
optimal. We consider some special families of totally postive matrices to show
non-trivial lower bounds on the number of repeated minors. In doing so, we
arrive at a new interesting problem: How many unit-area and axis-parallel
rectangles can be spanned by two points in a set of $n$ points in the plane?
This problem seems to be interesting in its own right especially since it seem
to have a flavor of additive combinatorics and relate to interesting incidence
problems where considering only the topology of the curves involved is not
enough. We prove an upper bound of $O(n^{\frac{4}{3}})$ and provide a lower
bound of $n^{1+\frac{1}{O(\log\log n)}}$.


title: Phase Separation Dynamics in Isotropic Ion-Intercalation Particles

abstract:
  Lithium-ion batteries exhibit complex nonlinear dynamics, resulting from
diffusion and phase transformations coupled to ion intercalation reactions.
Using the recently developed Cahn-Hilliard reaction (CHR) theory, we
investigate a simple mathematical model of ion intercalation in a spherical
solid nanoparticle, which predicts transitions from solid-solution radial
diffusion to two-phase shrinking-core dynamics. This general approach extends
previous Li-ion battery models, which either neglect phase separation or
postulate a spherical shrinking-core phase boundary, by predicting phase
separation only under appropriate circumstances. The effect of the applied
current is captured by generalized Butler-Volmer kinetics, formulated in terms
of diffusional chemical potentials, and the model consistently links the
evolving concentration profile to the battery voltage. We examine sources of
charge/discharge asymmetry, such as asymmetric charge transfer and surface
"wetting" by ions within the solid, which can lead to three distinct phase
regions. In order to solve the fourth-order nonlinear CHR
initial-boundary-value problem, a control-volume discretization is developed in
spherical coordinates. The basic physics are illustrated by simulating many
representative cases, including a simple model of the popular cathode material,
lithium iron phosphate (neglecting crystal anisotropy and coherency strain).
Analytical approximations are also derived for the voltage plateau as a
function of the applied current.


title:
Field dependent Anisotropic Micro Rheological and Microstructrual
  properties of Ferrofluids

abstract:
  We have measured micro-rheological and micro-structural properties of a super
paramagnetic ferrofluid made of Mn$_{0.75}$Zn$_{0.25}$Fe$_2$O$_4$ (MZF)
nanoparticles, using passive microrheology in a home built inverted microscope.
Thermal motion of a probe microsphere was measured for different values of an
applied external magnetic field and analysed. The analysis shows anisotropy in
magnetoviscous effect. Additional microrheological properties, such as storage
modulus and loss modulus and their transition is seen. Following the analysis
given in \cite{Oliver Muller, Stefan Mahle}, we have obtained microstructural
properties such as elongational flow coefficient $\lambda_2$, relaxation time
constant $\tau$, coefficient of dissipative magnetization $\alpha$ etc. From a
single set of viscosity data, all the above parameters could be obtained. Our
values for the above parameters are in agreement with earlier theoretical
calculations and macro-rheological experimental measurements.


title:
Further results on "Velocity-position integration formula, part
  I-Application to in-flight alignment"

abstract:
  This note improves our above-mentioned recent work by effectively depressing
the adverse effect of the lever arm on attitude estimation.


title: Density functions in high-dimensional basket options

abstract:
  We consider an important class of derivative contracts written on multiple
assets (so-called spread options) which are traded on a wide range of financial
markets. The present paper introduces a new approximation method of density
functions arising in high-dimensional basket options which is based on
applications of generalised Nyquist-Whitakker-Kotel'nikov-Shannon theorem we
established. It is shown that the method of approximation we propose has an
exponential rate of convergence in various situations.


title: Orthogonality and Dimensionality

abstract:
  In this article, we present what we believe to be a simple way to motivate
the use of Hilbert spaces in quantum mechanics. To achieve this, we study the
way the notion of dimension can, at a very primitive level, be defined as the
cardinality of a maximal collection of mutually orthogonal elements (which, for
instance, can be seen as spatial directions). Following this idea, we develop a
formalism based on two basic ingredients, namely an orthogonality relation and
matroids which are a very generic algebraic structure permitting to define a
notion of dimension. Having obtained what we call orthomatroids, we then show
that, in high enough dimension, the basic ingredients of orthomatroids (more
precisely the simple and irreducible ones) are isomorphic to generalized
Hilbert lattices, so that the latter are a direct consequence of an
orthogonality-based characterization of dimension.


title:
Edge currents and eigenvalue estimates for magnetic barrier
  Schr\"odinger operators

abstract:
  We study two-dimensional magnetic Schr\"odinger operators with a magnetic
field that is equal to b>0 for x > 0 and (-b) for x < 0. This magnetic
Schr\"odinger operator exhibits a magnetic barrier at x=0. The unperturbed
system is invariant with respect to translations in the y-direction. As a
result, the Schr\"odinger operator admits a direct integral decomposition. We
analyze the band functions of the fiber operators as functions of the wave
number and establish their asymptotic behavior. Because the fiber operators are
reflection symmetric, the band functions may be classified as odd or even. The
odd band functions have a unique absolute minimum. We calculate the effective
mass at the minimum and prove that it is positive. The even band functions are
monotone decreasing. We prove that the eigenvalues of an Airy operator,
respectively, harmonic oscillator operator, describe the asymptotic behavior of
the band functions for large negative, respectively positive, wave numbers. We
prove a Mourre estimate for perturbations of the magnetic Schr\"odinger
operator and establish the existence of absolutely continuous spectrum in
certain energy intervals. We prove lower bounds on magnetic edge currents for
states with energies in the same intervals. We also prove that these lower
bounds imply stable lower bounds for the asymptotic currents. We study the
perturbation by slowly decaying negative potentials and establish the
asymptotic behavior of the eigenvalue counting function for the infinitely-many
eigenvalues below the bottom of the essential spectrum.


title:
A revised uncertainty budget for measuring the Boltzmann constant using
  the Doppler Broadening Technique on ammonia

abstract:
  We report on our on-going effort to measure the Boltzmann constant, kB, using
the Doppler Broadening Technique. The main systematic effects affecting the
measurement are discussed. A revised error budget is presented in which the
global uncertainty on systematic effects is reduced to 2.3 ppm. This
corresponds to a reduction of more than one order of magnitude compared to our
previous Boltzmann constant measurement. Means to reach a determination of kB
at the part per million accuracy level are outlined.