title: Invariant Connections in Loop Quantum Gravity

abstract:
  Given a group $G$ and an abelian $C^*$-algebra $\mathfrak{A}$, the
antihomomorphisms $\Theta\colon G\rightarrow \mathrm{Aut}(\mathfrak{A})$ are in
one-to-one with those left actions $\Phi\colon G\times
\mathrm{Spec}(\mathfrak{A})\rightarrow \mathrm{Spec}(\mathfrak{A})$ whose
translation maps $\Phi_g$ are continuous; whereby continuities of $\Theta$ and
$\Phi$ turn out to be equivalent if $\mathfrak{A}$ is unital. In particular, a
left action $\phi\colon G \times X\rightarrow X$ can be uniquely extended to
the spectrum of a $C^*$-subalgebra $\mathfrak{A}$ of the bounded functions on
$X$ if $\phi_g^*(\mathfrak{A})\subseteq \mathfrak{A}$ holds for each $g\in G$.
In the present paper, we apply this to the framework of loop quantum gravity.
We show that, on the level of the configuration spaces, quantization and
reduction in general do not commute, i.e., that the symmetry-reduced quantum
configuration space is (strictly) larger than the quantized configuration space
of the reduced classical theory. Here, the quantum-reduced space has the
advantage to be completely characterized by a simple algebraic relation,
whereby the quantized reduced classical space is usually hard to compute.


title: Entangling mobility and interactions in social media

abstract:
  Daily interactions naturally define social circles. Individuals tend to be
friends with the people they spend time with and they choose to spend time with
their friends, inextricably entangling physical location and social
relationships. As a result, it is possible to predict not only someone's
location from their friends' locations but also friendship from spatial and
temporal co-occurrence. While several models have been developed to separately
describe mobility and the evolution of social networks, there is a lack of
studies coupling social interactions and mobility. In this work, we introduce a
new model that bridges this gap by explicitly considering the feedback of
mobility on the formation of social ties. Data coming from three online social
networks (Twitter, Gowalla and Brightkite) is used for validation. Our model
reproduces various topological and physical properties of these networks such
as: i) the size of the connected components, ii) the distance distribution
between connected users, iii) the dependence of the reciprocity on the
distance, iv) the variation of the social overlap and the clustering with the
distance. Besides numerical simulations, a mean-field approach is also used to
study analytically the main statistical features of the networks generated by
the model. The robustness of the results to changes in the model parameters is
explored, finding that a balance between friend visits and long-range random
connections is essential to reproduce the geographical features of the
empirical networks.


title:
Uniformity and self-neglecting functions: II. Beurling Regular Variation
  and the class {\Gamma}

abstract:
  Beurling slow variation is generalized to Beurling regular variation. A
Uniform Convergence Theorem, not previously known, is proved for those
functions of this class that are measurable or have the Baire property. This
permits their characterization and representation. This extends the gamma class
of de Haan theory studied earlier.


title:
Search for a light Higgs boson decaying to two gluons or ss-bar in the
  radiative decays of Y(1S)

abstract:
  We search for the decay Y(1S) -> gamma A0, A0 -> gg or ss-bar, where A0 is
the pseudoscalar light Higgs boson predicted by the next-to-minimal
supersymmetric standard model. We use a sample of (17.6 +- 0.3)x 10^6 Y(1S)
mesons produced in the BaBar experiment via e+e- -> Y(2S) -> pi+pi-Y(1S). We
see no significant signal and set 90%-confidence-level upper limits on the
product branching fraction B(Y(1S) -> gamma A0) x B(A0 -> gg or ss-bar) ranging
from 10^-6 to 10^-2 for A0 masses in the range 0.5 to 9.0GeV/c^2.


title:
Error-analysis and comparison to analytical models of numerical
  waveforms produced by the NRAR Collaboration

abstract:
  The Numerical-Relativity-Analytical-Relativity (NRAR) collaboration is a
joint effort between members of the numerical relativity, analytical relativity
and gravitational-wave data analysis communities. The goal of the NRAR
collaboration is to produce numerical-relativity simulations of compact
binaries and use them to develop accurate analytical templates for the
LIGO/Virgo Collaboration to use in detecting gravitational-wave signals and
extracting astrophysical information from them. We describe the results of the
first stage of the NRAR project, which focused on producing an initial set of
numerical waveforms from binary black holes with moderate mass ratios and
spins, as well as one non-spinning binary configuration which has a mass ratio
of 10. All of the numerical waveforms are analysed in a uniform and consistent
manner, with numerical errors evaluated using an analysis code created by
members of the NRAR collaboration. We compare previously-calibrated,
non-precessing analytical waveforms, notably the effective-one-body (EOB) and
phenomenological template families, to the newly-produced numerical waveforms.
We find that when the binary's total mass is ~100-200 solar masses, current EOB
and phenomenological models of spinning, non-precessing binary waveforms have
overlaps above 99% (for advanced LIGO) with all of the non-precessing-binary
numerical waveforms with mass ratios <= 4, when maximizing over binary
parameters. This implies that the loss of event rate due to modelling error is
below 3%. Moreover, the non-spinning EOB waveforms previously calibrated to
five non-spinning waveforms with mass ratio smaller than 6 have overlaps above
99.7% with the numerical waveform with a mass ratio of 10, without even
maximizing on the binary parameters.


title: Mixing Patterns from the Groups Sigma (n phi)

abstract:
  We survey the mixing patterns which can be derived from the discrete groups
Sigma (36 x 3), Sigma (72 x 3), Sigma (216 x 3) and Sigma (360 x 3), if these
are broken to abelian subgroups Ge and Gnu in the charged lepton and neutrino
sector, respectively. Since only Sigma (360 x 3) possesses Klein subgroups,
only this group allows neutrinos to be Majorana particles. We find a few
patterns that can agree well with the experimental data on lepton mixing in
scenarios with small corrections and that predict the reactor mixing angle
theta_{13} to be 0.1 <= theta_{13} <= 0.2. All these patterns lead to a trivial
Dirac phase. Patterns which instead reveal CP violation tend to accommodate the
data not well. We also comment on the outer automorphisms of the discussed
groups, since they can be useful for relating inequivalent representations of
these groups.


title: Arbitrarily large steady-state bosonic squeezing via dissipation

abstract:
  We discuss how large amounts of steady-state quantum squeezing (beyond 3 dB)
of a mechanical resonator can be obtained by driving an optomechanical cavity
with two control lasers with differing amplitudes. The scheme does not rely on
any explicit measurement or feedback, nor does it simply involve a modulation
of an optical spring constant. Instead, it uses a dissipative mechanism with
the driven cavity acting as an engineered reservoir. It can equivalently be
viewed as a coherent feedback process, obtained by minimally perturbing the
quantum nondemolition measurement of a single mechanical quadrature. This shows
that in general the concepts of coherent feedback schemes and reservoir
engineering are closely related. We analyze how to optimize the scheme, how the
squeezing scales with system parameters, and how it may be directly detected
from the cavity output. Our scheme is extremely general, and could also be
implemented with, e.g., superconducting circuits.


title:
Non-dissipative space-time $hp$-discontinuous Galerkin method for the
  time-dependent Maxwell Equations

abstract:
  A finite element method for the solution of the time-dependent Maxwell
equations in mixed form is presented. The method allows for local
$hp$-refinement in space and in time. To this end, a space-time Galerkin
approach is employed. In contrast to the space-time DG method introduced in
\cite{vegt_space_2002} test and trial space do not coincide. This allows for
obtaining a non-dissipative method. In order to obtain an efficient
implementation, a hierarchical tensor product basis in space and time is
proposed. In particular it allows to evaluate the local residual with a
complexity of $\mathcal{O}(p^4)$ and $\mathcal{O}(p^5)$ for affine and
non-affine elements, respectively.


title:
Perfect squeezing by damping modulation in circuit quantum
  electrodynamics

abstract:
  Dissipation-driven quantum state engineering uses the environment to steer
the state of quantum systems and preserve quantum coherence in the steady
state. We show that modulating the damping rate of a microwave resonator
generates a vacuum squeezed state of arbitrary squeezing strength, thereby
constituting a mechanism allowing perfect squeezing. Given the recent
experimental realizations in circuit QED of a microwave resonator with a
tunable damping rate [Yin et al., Phys. Rev. Lett. 110, 107001 (2013)],
superconducting circuits are an ideal playground to implement this technique.
By dispersively coupling a qubit to the microwave resonator, it is possible to
obtain qubit-state dependent squeezing.


title:
Roadmap for Ultra-High Energy Cosmic Ray Physics and Astronomy
  (whitepaper for Snowmass 2013)

abstract:
  We summarize the remarkable recent progress in ultra-high energy cosmic ray
physics and astronomy enabled by the current generation of cosmic ray
observatories. We discuss the primary objectives for future measurements and
describe the plans for near-term enhancements of existing experiments as well
as the next generation of observatories.


title: Upper Bound Estimates for Eigenvalues of the Poly-Laplacian

abstract:
  In this paper, we obtain a sharp upper bound for the sum of the first $k$-th
eigenvalues for this Dirichlet problem of poly-Laplacian with any order, which
is viewed as an extension of the result due to Cheng and Wei (Journal of
Differential Equations, 255 (2013), 220-233). In particular, if $l=2$ and $k$
is large enough, we give an important improvement of their result.


title:
Spacelike Self-Similar Shrinking Solutions of the Mean Curvature Flow in
  Pseudo-Euclidean Spaces

abstract:
  I classify spacelike self-similar shrinking solutions of the mean curvature
flow in pseudo-euclidean space in arbitrary codimension, if the mean curvature
vector is not a null vector and the principal normal vector is parallel in the
normal bundle. Moreover, I exclude the existence of such self-shrinkers in
several cases. The classification is analogous to the existing classifications
in the euclidean case of Huisken and Smoczyk.


title: Non-Abelian geometric phases in a system of coupled quantum bits

abstract:
  A common strategy to measure the Abelian geometric phase for a qubit is to
let it evolve along an 'orange slice' shaped path connecting two antipodal
points on the Bloch sphere by two different semi- great circles. Since the
dynamical phases vanish for such paths, this allows for direct measurement of
the geometric phase. Here, we generalize the orange slice setting to the
non-Abelian case. The proposed method to measure the non-Abelian geometric
phase can be implemented in a cyclic chain of four qubits with controllable
interactions.


title:
The O3N2 and N2 abundance indicators revisited: improved calibrations
  based on CALIFA and Te-based literature data

abstract:
  The use of IFS is since recently allowing to measure the emission line fluxes
of an increasingly large number of star-forming galaxies both locally and at
high redshift. The main goal of this study is to review the most widely used
empirical oxygen calibrations, O3N2 and N2, by using new direct abundance
measurements. We pay special attention to the expected uncertainty of these
calibrations as a function of the index value or abundance derived and the
presence of possible systematic offsets. This is possible thanks to the
analysis of the most ambitious compilation of Te-based HII regions to date.
This new dataset compiles the Te-based abundances of 603 HII regions extracted
from the literature but also includes new measurements from the CALIFA survey.
Besides providing new and improved empirical calibrations for the gas
abundance, we also present here a comparison between our revisited calibrations
with a total of 3423 additional CALIFA HII complexes with abundances derived
using the ONS calibration by Pilyugin et al. (2010). The combined analysis of
Te-based and ONS abundances allows us to derive their most accurate calibration
to date for both the O3N2 and N2 single-ratio indicators, in terms of all
statistical significance, quality and coverage of the space of parameters. In
particular, we infer that these indicators show shallower abundance
dependencies and statistically-significant offsets compared to those of Pettini
and Pagel (2004), Nagao et al. (2006) and P\'erez-Montero and Contini (2009).
The O3N2 and N2 indicators can be empirically applied to derive oxygen
abundances calibrations from either direct abundance determinations with random
errors of 0.18 and 0.16, respectively, or from indirect ones (but based on a
large amount of data) reaching an average precision of 0.08 and 0.09 dex
(random) and 0.02 and 0.08 dex (systematic; compared to the direct
estimations),respectively.


title: Reducible surgeries and Heegaard Floer homology

abstract:
  In this paper, we use Heegaard Floer homology to study reducible surgeries.
In particular, suppose K is a non-cable knot in the three-sphere with an
L-space surgery. If p-surgery on K is reducible, we show that p equals 2g(K)-1.
This implies that any knot with an L-space surgery has at most one reducible
surgery, a fact that we show additionally for any knot of genus at most two.


title: Quantum parameter estimation using general single-mode Gaussian states

abstract:
  We calculate the quantum Cram\'er--Rao bound for the sensitivity with which
one or several parameters, encoded in a general single-mode Gaussian state, can
be estimated. This includes in particular the interesting case of mixed
Gaussian states. We apply the formula to the problems of estimating phase,
purity, loss, amplitude, and squeezing. In the case of the simultaneous
measurement of several parameters, we provide the full quantum Fisher
information matrix. Our results unify previously known partial results, and
constitute a complete solution to the problem of knowing the best possible
sensitivity of measurements based on a single-mode Gaussian state.


title: Tipping points in macroeconomic Agent-Based models

abstract:
  The aim of this work is to explore the possible types of phenomena that
simple macroeconomic Agent-Based models (ABM) can reproduce. We propose a
methodology, inspired by statistical physics, that characterizes a model
through its 'phase diagram' in the space of parameters. Our first motivation is
to understand the large macro-economic fluctuations observed in the 'Mark I'
ABM. Our major finding is the generic existence of a phase transition between a
'good economy' where unemployment is low, and a 'bad economy' where
unemployment is high. We introduce a simpler framework that allows us to show
that this transition is robust against many modifications of the model, and is
generically induced by an asymmetry between the rate of hiring and the rate of
firing of the firms. The unemployment level remains small until a tipping
point, beyond which the economy suddenly collapses. If the parameters are such
that the system is close to this transition, any small fluctuation is amplified
as the system jumps between the two equilibria. We have explored several
natural extensions of the model. One is to introduce a bankruptcy threshold,
limiting the leverage of firms. This leads to a rich phase diagram with, in
particular, a region where acute endogenous crises occur, during which the
unemployment rate shoots up before the economy can recover. We also introduce
simple wage policies. This leads to inflation (in the 'good' phase) or
deflation (in the 'bad' phase), but leaves the overall phase diagram of the
model essentially unchanged. We have also started exploring the effect of
simple monetary policies that attempt to contain rising unemployment and defang
crises. We end the paper with general comments on the usefulness of ABMs to
model macroeconomic phenomena, in particular in view of the time needed to
reach a steady state that raises the issue of ergodicity in these models.


title: Rare baryonic decays $\Lambda_b \to \Lambda l^+ l^-$ in the TTM model

abstract:
  In the framework of the top triangle moose $(TTM)$ model, we analyze the rare
decays $\Lambda_{b}\rightarrow \Lambda l^{+}l^{-} (l=e,\mu,\tau)$ by using the
form factors calculated in full $QCD$. We calculate the contributions of the
new particles predicted by this model to observables, such as the branching
ratios, forward-backward asymmetry ($A_{FB}$) and polarizations related these
decay processes. We find that, in wide range of the parameter space, the values
of the branching ratios are enhanced by one order of magnitude comparing to the
$SM$ predictions. This model can also produce significant corrections to
$A_{FB}$, normal polarization $P_N$ and transversal polarization $P_T$.


title:
The Complexity of Reachability Problems for Flat Counter Machines with
  Periodic Loops

abstract:
  This paper proves the NP-completeness of the reachability problem for the
class of flat counter machines with difference bounds and, more generally,
octagonal relations, labeling the transitions on the loops. The proof is based
on the fact that the sequence of powers $\{R^i\}_{i=1}^\infty$ of such
relations can be encoded as a periodic sequence of matrices, and that both the
prefix and the period of this sequence are $2^{\mathcal{O}(\bin{R})}$ in the
size of the binary encoding $\bin{R}$ of a relation $R$. This result allows to
characterize the complexity of the reachability problem for one of the most
studied class of counter machines \cite{cav10,comon-jurski98}, and has a
potential impact for other problems in program verification.


title:
Ontology alignment repair through modularization and confidence-based
  heuristics

abstract:
  Ontology Matching aims to find a set of semantic correspondences, called an
alignment, between related ontologies. In recent years, there has been a
growing interest in efficient and effective matching methods for large
ontologies. However, most of the alignments produced for large ontologies are
logically incoherent. It was only recently that the use of repair techniques to
improve the quality of ontology alignments has been explored. In this paper we
present a novel technique for detecting incoherent concepts based on ontology
modularization, and a new repair algorithm that minimizes the incoherence of
the resulting alignment and the number of matches removed from the input
alignment. An implementation was done as part of a lightweight version of
AgreementMaker system, a successful ontology matching platform, and evaluated
using a set of four benchmark biomedical ontology matching tasks. Our results
show that our implementation is efficient and produces better alignments with
respect to their coherence and f-measure than the state of the art repairing
tools. They also show that our implementation is a better alternative for
producing coherent silver standard alignments.


title: Dark-Matter Harmonics Beyond Annual Modulation

abstract:
  The count rate at dark-matter direct-detection experiments should modulate
annually due to the motion of the Earth around the Sun. We show that
higher-frequency modulations, including daily modulation, are also present and
in some cases are nearly as strong as the annual modulation. These higher-order
modes are particularly relevant if (i) the dark matter is light, O(10) GeV,
(ii) the scattering is inelastic, or (iii) velocity substructure is present;
for these cases, the higher-frequency modes are potentially observable at
current and ton-scale detectors. We derive simple expressions for the harmonic
modes as functions of the astrophysical and geophysical parameters describing
the Earth's orbit, using an updated expression for the Earth's velocity that
corrects a common error in the literature. For an isotropic halo velocity
distribution, certain ratios of the modes are approximately constant as a
function of nuclear recoil energy. Anisotropic distributions can also leave
observable features in the harmonic spectrum. Consequently, the higher-order
harmonic modes are a powerful tool for identifying a potential signal from
interactions with the Galactic dark-matter halo.


title:
A Search for Fast Optical Transients in the Pan-STARRS1 Medium-Deep
  Survey: M Dwarf Flares, Asteroids, Limits on Extragalactic Rates, and
  Implications for LSST

abstract:
  [Abridged] We present a search for fast optical transients (~0.5 hr-1 day)
using repeated observations of the Pan-STARRS1 Medium-Deep Survey (PS1/MDS)
fields. Our search takes advantage of the consecutive g/r-band observations
(16.5 min in each filter), by requiring detections in both bands, with
non-detections on preceding and subsequent nights. We identify 19 transients
brighter than 22.5 AB mag (S/N>10). Of these, 11 events exhibit quiescent
counterparts in the deep PS1/MDS templates that we identify as M4-M9 dwarfs.
The remaining 8 transients exhibit a range of properties indicative of
main-belt asteroids near the stationary point of their orbits. With
identifications for all 19 transients, we place an upper limit of
R_FOT(0.5hr)<0.12 deg^-2 d^-1 (95% confidence level) on the sky-projected rate
of extragalactic fast transients at <22.5 mag, a factor of 30-50 times lower
than previous limits; the limit for a timescale of ~day is R_FOT<2.4e-3 deg^-2
d^-1. To convert these sky-projected rates to volumetric rates, we explore the
expected peak luminosities of fast optical transients powered by various
mechanisms, and find that non-relativistic events are limited to M~-10 mag
(M~-14 mag) for a timescale of ~0.5 hr (~day), while relativistic sources
(e.g., GRBs, magnetar-powered transients) can reach much larger luminosities.
The resulting volumetric rates are <13 (M~-10 mag), <0.05 (M~-14 mag) and <1e-6
Mpc^-3 yr^-1 (M~-24 mag), significantly above the nova, supernova, and GRB
rates, respectively, indicating that much larger surveys are required to
provide meaningful constraints. Motivated by the results of our search we
discuss strategies for identifying fast optical transients in the LSST main
survey, and reach the optimistic conclusion that the veil of foreground
contaminants can be lifted with the survey data, without the need for expensive
follow-up observations.


title: Entanglement Entropy for Probe Branes

abstract:
  We give a prescription for calculating the entanglement entropy in
holographic probe brane systems by systematically taking the leading order
backreaction of the probe brane into account. We find a simple compact double
integral formula, which is insensitive to many details of the backreaction,
most notably the internal space or the non-metric fields sourced by the probe.
We validate our method by comparing to exact results in solvable toy models. We
also determine the entanglement entropies for a sphere and a strip in the
top-down D3/D7 and D3/D5 system. For the sphere the entanglement entropy has
also been obtained by other methods and we find perfect agreement.


title:
Kinetic or thermal AGN feedback in simulations of isolated and merging
  disk galaxies calibrated by the M-sigma relation

abstract:
  (Abridged) We investigate two modes of coupling the feedback energy from a
central AGN to the neighboring gas in galaxy simulations: kinetic - velocity
boost, and thermal - heating. We formulate kinetic feedback models for
energy-driven wind (EDW) and momentum-driven wind (MDW), using two free
parameters: feedback efficiency epsilon_f, and AGN wind velocity v_w. A novel
numerical algorithm is implemented in the SPH code GADGET-3, to prevent the
expansion of a hole in the gas distribution around the BH. We perform
simulations of isolated evolution and merger of disk galaxies, of Milky-Way
mass as well as lower and higher masses. We find that in the isolated galaxy BH
kinetic feedback generates intermittent bipolar jet-like gas outflows. We infer
that current prescriptions for BH subgrid physics in galaxy simulations can
grow the BH to observed values even in an isolated disk galaxy. The BH growth
is enhanced in a galaxy merger. Comparing the [M_BH - sigma_star] relation
obtained in our simulations with observational data, we conclude that it is
possible to find parameter sets for a fit in all the models, except for the
case with MDW feedback in a galaxy merger, in which the BH is always too
massive. The BH thermal feedback implementation of Springel, Di Matteo &
Hernquist (2005) within the multiphase star-formation model is found to have
negligible impact on gas properties; and the effect claimed in all previous
studies is attributed to gas depletion around the BH by the creation of an
artificial hole. The BH mass accretion rate in our simulations exhibit heavy
fluctuations. The star formation rate is quenched with feedback by removal of
gas. The CGM gas at galactocentric distances (20 - 100)/h kpc are found to give
the best metallicity observational diagnostic to distinguish between BH models.


title:
Sensitivity of future collider facilities to WIMP pair production via
  effective operators and light mediators

abstract:
  We present extrapolations of the current mono-jet searches at the LHC to
potential future hadron collider facilities: LHC14, as well as $pp$ colliders
with $\sqrt{s}=33$ or 100 TeV. We consider both the effective operator approach
as well as one example of a light mediating particle.


title:
The Diophantine equation xy=z^n; for n=2,3,4,5,6; the Diophantine
  equation xyz=w^2; and the Diophantine system: xy=v^2 and yz=w^2

abstract:
  In this work, we accomplish three goals. First, we determine the entire
family of positive integer solutions to the three- variable Diophantine
equation, xy=z^2; for n=2,3,4,5,6. For n=2, we obtain a 3-parameter family of
solutions; for n=3, a 5-parameter of solutions; likewise for n=4. For n=5, a
7-parameter family of solutions; and likewise for n=6. See Theorems 2 through 6
respectively. The second goal of this paper, is determining all the positive
integer solutions of xyz=w^2. This is done in Theorem7; the solution set is
described in terms of six independent parameters. Finally, in Theorem 8, we
achieve our third goal: determining all the positive integer solutions of the
5-variable Diophantine system: xy=v^2 and yz=w^2. The solution set is expressed
in terms of eight parameters. This paper contains a total of four references.


title: Suffix conjugates for a class of morphic subshifts

abstract:
  Let A be a finite alphabet and f: A^* --> A^* be a morphism with an iterative
fixed point f^\omega(\alpha), where \alpha{} is in A. Consider the subshift (X,
T), where X is the shift orbit closure of f^\omega(\alpha) and T: X --> X is
the shift map. Let S be a finite alphabet that is in bijective correspondence
via a mapping c with the set of nonempty suffixes of the images f(a) for a in
A. Let calS be a subset S^N be the set of infinite words s = (s_n)_{n\geq 0}
such that \pi(s):= c(s_0)f(c(s_1)) f^2(c(s_2))... is in X. We show that if f is
primitive and f(A) is a suffix code, then there exists a mapping H: calS -->
calS such that (calS, H) is a topological dynamical system and \pi: (calS, H)
--> (X, T) is a conjugacy; we call (calS, H) the suffix conjugate of (X, T). In
the special case when f is the Fibonacci or the Thue-Morse morphism, we show
that the subshift (calS, T) is sofic, that is, the language of calS is regular.


title:
On Computing the Elimination Ideal Using Resultants with Applications to
  Gr\"obner Bases

abstract:
  Resultants and Gr\"obner bases are crucial tools in studying polynomial
elimination theory. We investigate relations between the variety of the
resultant of two polynomials and the variety of the ideal they generate. Then
we focus on the bivariate case, in which the elimination ideal is principal. We
study - by means of elementary tools - the difference between the multiplicity
of the factors of the generator of the elimination ideal and the multiplicity
of the factors of the resultant.


title:
Finite one-loop radiative corrections in the Lorentz- and CPT-violating
  QED extension

abstract:
  We report on our current progress in the study of finite one-loop radiative
corrections in the minimal Lorentz- and CPT-violating QED extension.


title: Random walks on free solvable groups

abstract:
  For any finitely generated group G, let n ---> \Phi_G(n) be the function that
describes the rough asymptotic behavior of the probability of return to the
identity element at time 2n of a symmetric simple random walk on G (this is an
invariant of quasi-isometry). We determine this function when G is the free
solvable group S_{d,r} of derived length d on r generators and some other
related groups.


title: Weighted fourth moments of Hecke zeta functions with groessencharacters

abstract:
  We use recently obtained bounds for sums of Kloosterman sums to bound the sum
$\sum_{-D\leq d\leq D} \int_{-D}^D |\zeta(1/2+it,\lambda^d)|^4|
\sum_{0<|\mu|^2\leq M} A(\mu)\lambda^d((\mu)) |\mu|^{-2it}|^2 {\rm d}t$, where
$\lambda^d$ is the groessencharacter satisfying $\lambda^d((\alpha)) =
\lambda^d(\alpha{\Bbb Z}[i]) = (\alpha /|\alpha|)^{4d}$, for
$0\neq\alpha\in{\Bbb Z}[i]$, and $\zeta(s,\lambda^d)$ is the Hecke zeta
function that satisfies $\zeta(s,\lambda^d) =(1/4)\sum_{0\neq\alpha\in{\Bbb
Z}[i]} \lambda^d((\alpha)) |\alpha|^{-2s}$ for $\Re(s)>1$, while the numbers
$D,M\in(0,\infty)$ and function $A:{\Bbb Z}[i]-\{0\}\rightarrow{\Bbb C}$ are
arbitrary (though it is only in respect of cases in which $M$ is relatively
small, compared to $D$, that our results are new and interesting). One of our
new bounds may have an application in enabling a certain improvement of a
result of P.A. Lewis on the distribution of Gaussian primes.


title:
Gold nanocrescents for remotely measuring and controlling local
  temperature

abstract:
  We present a novel technique to remotely measure and control the local
temperature within a medium. This technique is based on the observation of the
rotational Brownian motion of gold nanocrescent particles, which possess a
strong anisotropic light interaction due to their plasmonic properties.
Rotational scattering correlation spectroscopy performed on a single
nanoparticle is able to determine the local temperature with high accuracy.
These nano-thermometers can simultaneously play the role of nano-heaters when
absorbing the light of a focused laser beam.


title: Mean Field Approximation to a Spatial Host-Pathogen Model

abstract:
  We study the mean field approximation to a simple spatial host-pathogen model
that has been shown to display interesting evolutionary properties. We show
that previous derivations of the mean field equations for this model are
actually only low-density approximations to the true mean field limit. We
derive the correct equations and the corresponding equations including
pair-correlations. The process of invasion by a mutant type of pathogen is also
discussed. [This article was published as Physical Review E 67, 047102 (2003).
Errata for the published version are corrected here and explicitly listed at
the end of this document.]


title: Good Debt or Bad Debt: Detecting Semantic Orientations in Economic Texts

abstract:
  The use of robo-readers to analyze news texts is an emerging technology trend
in computational finance. In recent research, a substantial effort has been
invested to develop sophisticated financial polarity-lexicons that can be used
to investigate how financial sentiments relate to future company performance.
However, based on experience from other fields, where sentiment analysis is
commonly applied, it is well-known that the overall semantic orientation of a
sentence may differ from the prior polarity of individual words. The objective
of this article is to investigate how semantic orientations can be better
detected in financial and economic news by accommodating the overall
phrase-structure information and domain-specific use of language. Our three
main contributions are: (1) establishment of a human-annotated finance
phrase-bank, which can be used as benchmark for training and evaluating
alternative models; (2) presentation of a technique to enhance financial
lexicons with attributes that help to identify expected direction of events
that affect overall sentiment; (3) development of a linearized phrase-structure
model for detecting contextual semantic orientations in financial and economic
news texts. The relevance of the newly added lexicon features and the benefit
of using the proposed learning-algorithm are demonstrated in a comparative
study against previously used general sentiment models as well as the popular
word frequency models used in recent financial studies. The proposed framework
is parsimonious and avoids the explosion in feature-space caused by the use of
conventional n-gram features.


title:
Spectral and homological properties of Hilbert modules over the disc
  algebra

abstract:
  We study general Hilbert modules over the disc algebra and exhibit necessary
spectral conditions for the vanishing of certain associated extension groups.
In particular, this sheds some light on the problem of identifying the
projective Hilbert modules. Part of our work also addresses the classical
derivation problem.


title:
Hubble Space Telescope observations of the afterglow, supernova and host
  galaxy associated with the extremely bright GRB 130427A

abstract:
  We present Hubble Space Telescope (HST) observations of the exceptionally
bright and luminous Swift gamma-ray burst, GRB 130427A. At z=0.34 this burst
affords an excellent opportunity to study the supernova and host galaxy
associated with an intrinsically extremely luminous burst ($E_{iso} >10^{54}$
erg): more luminous than any previous GRB with a spectroscopically associated
supernova. We use the combination of the image quality, UV capability and and
invariant PSF of HST to provide the best possible separation of the afterglow,
host and supernova contributions to the observed light ~17 rest-frame days
after the burst utilising a host subtraction spectrum obtained 1 year later.
Advanced Camera for Surveys (ACS) grism observations show that the associated
supernova, SN~2013cq, has an overall spectral shape and luminosity similar to
SN 1998bw (with a photospheric velocity, v$_{ph}$ ~15,000 km/s). The positions
of the bluer features are better matched by the higher velocity SN~2010bh
(v$_{ph}$ ~ 30,000 km/s), but SN 2010bh is significantly fainter, and fails to
reproduce the overall spectral shape, perhaps indicative of velocity structure
in the ejecta. We find that the burst originated ~4 kpc from the nucleus of a
moderately star forming (1 Msol/yr), possibly interacting disc galaxy. The
absolute magnitude, physical size and morphology of this galaxy, as well as the
location of the GRB within it are also strikingly similar to those of
GRB980425/SN 1998bw. The similarity of supernovae and environment from both the
most luminous and least luminous GRBs suggests broadly similar progenitor stars
can create GRBs across six orders of magnitude in isotropic energy.


title:
The Cluster Graphical Lasso for improved estimation of Gaussian
  graphical models

abstract:
  We consider the task of estimating a Gaussian graphical model in the
high-dimensional setting. The graphical lasso, which involves maximizing the
Gaussian log likelihood subject to an l1 penalty, is a well-studied approach
for this task. We begin by introducing a surprising connection between the
graphical lasso and hierarchical clustering: the graphical lasso in effect
performs a two-step procedure, in which (1) single linkage hierarchical
clustering is performed on the variables in order to identify connected
components, and then (2) an l1-penalized log likelihood is maximized on the
subset of variables within each connected component. In other words, the
graphical lasso determines the connected components of the estimated network
via single linkage clustering. Unfortunately, single linkage clustering is
known to perform poorly in certain settings. Therefore, we propose the cluster
graphical lasso, which involves clustering the features using an alternative to
single linkage clustering, and then performing the graphical lasso on the
subset of variables within each cluster. We establish model selection
consistency for this technique, and demonstrate its improved performance
relative to the graphical lasso in a simulation study, as well as in
applications to an equities data set, a university webpage data set, and a gene
expression data set.


title: Unitarity in higher-order Lorentz-invariance violating QED

abstract:
  The unitarity in Lorentz invariance violating QED consisting of standard
fermions and higher-order photons of the Myers-Pospelov theory is studied. We
find ghost states associated to the higher-order character of the theory which
could render the $S$ matrix nonunitary. An explicit calculation to check
perturbative unitarity in the process of electron-positron scattering is
performed and it is found to be possible to preserve unitarity.


title: Unitarity, ghosts and nonminimal terms in Lorentz violating QED

abstract:
  The unitarity of a Lorentz-invariance violating QED model with higher-order
Myers and Pospelov photons coupled to standard fermions is studied. As
expected, we find ghost states associated to the higher-order terms that may
lead to the loss of unitarity. An explicit calculation to check perturbative
unitarity in the process of electron-positron scattering is performed and it is
found to be possible to be preserved.


title:
Democracy of shearlet bases with applications to approximation and
  interpolation

abstract:
  Shearlets on the cone provide Parseval frames for $L^2$. They also provide
near-optimal approximation for the class $\mathcal{E}$ of cartoon-like images.
Moreover, there are spaces associated to them other than $L^2$ and there exist
embeddings between these and classical spaces.
  We prove approximation properties of the cone-adapted shearlets in a more
general context, namely, when the target function belongs to a class or space
different to $\mathcal{E}$ and when the error is not necessarily measured in
the $L^2$-norm but in a much wider family of smoothness space of high
anisotropy.


title:
Large time behavior of solutions to semi-linear equations with quadratic
  growth in the gradient

abstract:
  This paper studies the large time behavior of solutions to semi-linear Cauchy
problems with quadratic nonlinearity in gradients. The Cauchy problem
considered has a general state space and may degenerate on the boundary of the
state space. Two types of large time behavior are obtained: i) pointwise
convergence of the solution and its gradient; ii) convergence of solutions to
associated backward stochastic differential equations. When the state space is
R^d or the space of positive definite matrices, both types of convergence are
obtained under growth conditions on model coefficients. These large time
convergence results have direct applications in risk sensitive control and long
term portfolio choice problems.


title: Helical swimming in Stokes flow using a novel boundary-element method

abstract:
  We apply the boundary-element method to Stokes flows with helical symmetry,
such as the flow driven by an immersed rotating helical flagellum. We show that
the two-dimensional boundary integral method can be reduced to one dimension
using the helical symmetry. The computational cost is thus much reduced while
spatial resolution is maintained. We review the robustness of this method by
comparing the simulation results with the experimental measurement of the
motility of model helical flagella of various ratios of pitch to radius, along
with predictions from resistive-force theory and slender-body theory. We also
show that the modified boundary integral method provides reliable convergence
if the singularities in the kernel of the integral are treated appropriately.


title: Weak coherence of groups and finite decomposition complexity

abstract:
  The weak regular coherence is a coarse property of a finitely generated group
$\Gamma$. It was introduced by G. Carlsson and this author to play the role of
a weakening of Waldhausen's regular coherence as part of computation of the
integral K-theoretic assembly map. A new class of metric spaces (sFDC) was
introduced recently by A. Dranishnikov and M. Zarichnyi. This class includes
most notably the spaces with finite decomposition complexity (FDC) studied by
E. Guentner, D. Ramras, R. Tessera, and G. Yu. The main theorem of this paper
shows that a group that has finite $K(\Gamma,1)$ and sFDC is weakly regular
coherent. As a consequence, the integral K-theoretic assembly maps are
isomorphisms in all dimensions for any group that has finite $K(\Gamma,1)$ and
FDC. In particular, the Whitehead group $Wh (\Gamma)$ is trivial for such
groups.


title: Supersingular distribution on average for congruence classes of primes

abstract:
  We demonstrate the existence of a congruence class bias in the distribution
of supersingular primes on average for elliptic curves over $\Q$. For example,
we show that on average there are twice as many supersingular primes congruent
to 2 mod 3 as there are congruent to 1 mod 3. Our result is obtained using the
averaging approach of Fouvry-Murty along with ideas of David-Pappalardi.


title:
Disorder effects on superconducting tendencies in the checkerboard
  Hubbard model

abstract:
  The question of whether spatially inhomogeneous hopping in the two
dimensional Hubbard model can lead to enhancement of superconductivity has been
tackled by a number of authors in the context of the checkerboard Hubbard model
(CHM). We address the effects of disorder on superconducting properties of the
CHM by using exact diagonalization calculations for both potential and hopping
disorder. We characterize the superconducting tendencies of the model by
focusing on the pair binding energy, the spin gap, and d-wave pairing order
parameter. We find that superconducting tendencies, particularly the pair
binding energy, are more robust to disorder when there is inhomogeneous hopping
than for the uniform Hubbard model. We also study all possible staggered
potentials for an eight site CHM cluster and relate the behaviour of these
configurations to the disordered system.


title:
Tensor-based formulation and nuclear norm regularization for
  multi-energy computed tomography

abstract:
  The development of energy selective, photon counting X-ray detectors allows
for a wide range of new possibilities in the area of computed tomographic image
formation. Under the assumption of perfect energy resolution, here we propose a
tensor-based iterative algorithm that simultaneously reconstructs the X-ray
attenuation distribution for each energy. We use a multi-linear image model
rather than a more standard "stacked vector" representation in order to develop
novel tensor-based regularizers. Specifically, we model the multi-spectral
unknown as a 3-way tensor where the first two dimensions are space and the
third dimension is energy. This approach allows for the design of tensor
nuclear norm regularizers, which like its two dimensional counterpart, is a
convex function of the multi-spectral unknown. The solution to the resulting
convex optimization problem is obtained using an alternating direction method
of multipliers (ADMM) approach. Simulation results shows that the generalized
tensor nuclear norm can be used as a stand alone regularization technique for
the energy selective (spectral) computed tomography (CT) problem and when
combined with total variation regularization it enhances the regularization
capabilities especially at low energy images where the effects of noise are
most prominent.


title:
k-resolved susceptibility function of 2H-TaSe2 from angle-resolved
  photoemission

abstract:
  The connection between the Fermi surface and charge-density wave (CDW) order
is revisited in 2H-TaSe2. Using angle-resolved photoemission spectroscopy, ab
initio band structure calculations, and an accurate tight-binding model, we
develop the empirical k-resolved susceptibility function, which we use to
highlight states that contribute to the susceptibility for a particular
q-vector. We show that although the Fermi surface is involved in the peaks in
the susceptibility associated with CDW order, it is not through conventional
Fermi surface nesting, but rather through finite energy transitions from states
located far from the Fermi level. Comparison with monolayer TaSe2 illustrates
the different mechanisms that are involved in the absence of bilayer splitting.


title: The Greene-Krantz Conjecture in Dimension Two

abstract:
  We give a proof of the Greene-Krantz conjecture on convex domains in $\CC^2$.
Curiously, the proof technique depends on subelliptic estimates for the
$\bar{\partial}$ problem.


title: Colorings of the n-sphere and inversive geometry

abstract:
  This paper shows that in dimensions n \geq 2 for any partition of the set of
points in the standard n-sphere \sum_{i=0}^n x_i^2 =1 in R^{n+1} into (n+3) or
more nonempty sets, there exists a hyperplane in R^{n+1} that intersects at
least (n+2) of these sets. This result is used to prove a result in inversive
geometry. A mapping T: S^2 \to S^n, for n\geq 2,not assumed continuous or even
measurable, is called weakly circle-preserving if the image of any circle is
contained in some circle in the range space S^n. If such a map T has a range
T(S^2) in circular general position, meaning that any circle in the S^n misses
at least two points of T(S^2), then T must be a Mobius transformation of S^2.


title: Cosine problem in EPRL/FK spinfoam model

abstract:
  We calculate the classical limit effective action of the EPRL/FK spinfoam
model of quantum gravity coupled to matter fields. By employing the standard
QFT background field method adapted to the spinfoam setting, we find that the
model has many different classical effective actions. Most notably, these
include the ordinary Einstein-Hilbert action coupled to matter, but also an
action which describes antigravity. All those multiple classical limits appear
as a consequence of of the fact that the EPRL/FK vertex amplitude has
cosine-like large spin asymptotics. We discuss some possible ways to eliminate
the unwanted classical limits.


title:
High-throughput Imaging and Spectroscopy of Individual Carbon Nanotubes
  in Devices with Light Microscopy

abstract:
  Two paramount challenges in carbon nanotube research are achieving
chirality-controlled synthesis and understanding chirality-dependent device
physics. High-throughput and in-situ chirality and electronic structural
characterization of individual carbon nanotubes is crucial for addressing these
challenges. Optical imaging and spectroscopy has unparalleled throughput and
specificity, but its realization for single nanotubes on substrates or in
devices has long been an outstanding challenge. Here we demonstrate video-rate
imaging and in-situ spectroscopy of individual carbon nanotubes on various
substrates and in functional devices using a novel high-contrast
polarization-based optical microscopy. Our technique enables the complete
chirality profiling of hundreds of as-grown carbon nanotubes. In addition, we
in-situ monitor nanotube electronic structure in active field-effect devices,
and observe that high-order nanotube optical resonances are dramatically
broadened by electrostatic doping. This unexpected behaviour points to strong
interband electron-electron scattering processes that can dominate ultrafast
dynamics of excited states in carbon nanotubes.


title:
Reversible diffusion-influenced reactions of an isolated pair on two
  dimensional surfaces

abstract:
  We investigate reversible diffusion-influenced reactions of an isolated pair
in two dimensions. To this end, we employ convolution relations that permit
deriving the survival probability of the reversible reaction directly in terms
of the survival probability of the irreversible reaction. Furthermore, we make
use of the mean reaction time approximation to write the irreversible survival
probability in restricted spaces as a single exponential. In this way, we
obtain exact and approximative expressions in the time domain for the
reversible survival probability for three different two dimensional diffusion
spaces: The infinite and restricted plane as well as the surface of a sphere.
Our obtained results should prove useful in the context of membrane-bound
reversible diffusion-influenced reactions in cell biology.


title:
Absolute and relative stability of an optical frequency reference based
  on spectral hole burning in Eu$^{3+}$:Y$_2$SiO$_5$

abstract:
  We present and analyze four frequency measurements designed to characterize
the performance of an optical frequency reference based on spectral hole
burning in \EuYSO. The first frequency comparison, between a single unperturbed
spectral hole and a hydrogen maser, demonstrates a fractional frequency drift
rate of $5 \times 10^{-18}$ s$^{-1}$. Optical-frequency comparisons between a
pattern of spectral holes, a Fabry-P\'erot cavity, and an Al$^+$ optical atomic
clock show a short-term fractional frequency stability of $1 \times10^{-15}
\tau^{-1/2}$ that averages down to $2.5^{+1.1}_{-0.5} \times 10^{-16}$ at $\tau
= 540~s$ (with linear frequency drift removed). Finally, spectral hole patterns
in two different \EuYSO crystals located in the same cryogenic vessel are
compared, yielding a short-term stability of $7 \times10^{-16} \tau^{-1/2}$
that averages down to $5.5^{+1.8}_{-0.9} \times 10^{-17}$ at $\tau = 204$~s
(with quadratic frequency drift removed).


title: OB stars in the Leading Arm of the Magellanic Stream

abstract:
  We present our spectroscopic program aimed to study some new interesting
features recently discovered in the Magellanic Cloud System. These were
revealed by the spatial distribution of OB-type candidate stars, selected based
on UV, optical and IR photometry and proper motions from existing large-area
catalogs. As a pilot study of our project, we are studying OB-star candidates
in the Leading Arm (LA) of the Magellanic Stream, a gaseous tidal structure
with no stellar counterpart known so far. Our targets group in three clumps
near regions of high HI density in the LA. If confirmed, these young stars
would evidence recent star formation in the LA, and they would help better
understand and constrain the formation of the LA and its interactions with the
Milky Way.


title: The nonvanishing hypothesis at infinity for Rankin-Selberg convolutions

abstract:
  We prove the nonvanishing hypothesis at infinity for Rankin-Selberg
convolutions for $\GL(n)\times \GL(n-1)$.


title:
Weak Localization Effects as Evidence for Bulk Quantization in Thin
  Films Bi2Se3

abstract:
  Strong spin-orbit coupling in topological insulators results in the
ubiquitously observed weak antilocalization feature in their magnetoresistance.
Here we present magnetoresistance measurements in ultra thin films of the
topological insulator Bi_2Se_3, and show that in the 2D quantum limit, in which
the topological insulator bulk becomes quantized, an additional negative
magnetoresistance feature appears. Detailed analysis associates this feature
with weak localization of the quantized bulk channels, providing thus evidence
for this quantization. Examination of the dephasing fields at different
temperatures indicates different scattering mechanism in the bulk vs the
surface states.


title:
Impact of $Z^{\prime}$ and UED parameters on different asymmetries in
  $B_{s} \to \phi \ell^{+} \ell^{-}$ decays

abstract:
  A comprehensive study of the impact of new-physics on different observables
for $B_{s}\to \phi \ell^{+}\ell^{-}$ has been done. We examine the new physics
models such as $Z^{\prime}$ and UED models, where the effects of new physics
coming through the modification of Wilson coefficients. We have analyzed these
effects through the theoretical prediction of the branching ratio, the
forward-backward asymmetry, lepton polarization asymmetries and the helicity
fractions of the final state meson. These all observables will definitely be
measured in present and future colliders with great precision. We also pointed
out that hadronic uncertainties in various physical observables are small which
make them an ideal probe to establish new physics. Therefore, the measurements
of these observables for the same decay would permit the detection of physics
beyond the Standard Model and will also help us to distinguish between
different new physics scenarios.


title: Equivalence Principle in Cosmology

abstract:
  We analyse the Einstein equivalence principle (EEP) for a Hubble observer in
Friedmann-Lemaitre-Robertson-Walker spacetime. We show that the affine
structure of light cone in the FLRW spacetime should be treated locally in
terms of the optical metric which is not reduced to the Minkowski metric due to
the non-uniform parametrization of the local equations of light propagation
with the proper time of the observer's clock. The physical consequence of this
difference is that the Doppler shift of radio waves measured locally, is
affected by the Hubble expansion.


title: The Gelfond-Schnirelman method in prime number theory

abstract:
  The original Gelfond-Schnirelman method, proposed in 1936, uses polynomials
with integer coefficients and small norms on $[0,1]$ to give a Chebyshev-type
lower bound in prime number theory. We study a generalization of this method
for polynomials in many variables. Our main result is a lower bound for the
integral of Chebyshev's $\psi$-function, expressed in terms of the weighted
capacity. This extends previous work of Nair and Chudnovsky, and connects the
subject to the potential theory with external fields generated by
polynomial-type weights. We also solve the corresponding potential theoretic
problem, by finding the extremal measure and its support.


title: Monic integer Chebyshev problem

abstract:
  We study the problem of minimizing the supremum norm by monic polynomials
with integer coefficients. Let ${\M}_n({\Z})$ denote the monic polynomials of
degree $n$ with integer coefficients. A {\it monic integer Chebyshev
polynomial} $M_n \in {\M}_n({\Z})$ satisfies $$ \| M_n \|_{E} = \inf_{P_n
\in{\M}_n ({\Z})} \| P_n \|_{E}. $$ and the {\it monic integer Chebyshev
constant} is then defined by $$ t_M(E) := \lim_{n \rightarrow \infty} \| M_n
\|_{E}^{1/n}. $$ This is the obvious analogue of the more usual {\it integer
Chebyshev constant} that has been much studied.
  We compute $t_M(E)$ for various sets including all finite sets of rationals
and make the following conjecture, which we prove in many cases.
  \medskip\noindent {\bf Conjecture.} {\it Suppose $[{a_2}/{b_2},{a_1}/{b_1}]$
is an interval whose endpoints are consecutive Farey fractions. This is
characterized by $a_1b_2-a_2b_1=1.$ Then} $$t_M[{a_2}/{b_2},{a_1}/{b_1}] =
\max(1/b_1,1/b_2).$$
  This should be contrasted with the non-monic integer Chebyshev constant case
where the only intervals where the constant is exactly computed are intervals
of length 4 or greater.


title: Approximation of conformal mapping via the Szeg\H{o} kernel method

abstract:
  We study the uniform approximation of the canonical conformal mapping, for a
Jordan domain onto the unit disk, by polynomials generated from the partial
sums of the Szeg\H{o} kernel expansion. These polynomials converge to the
conformal mapping uniformly on the closure of any Smirnov domain. We prove
estimates for the rate of such convergence on domains with piecewise analytic
boundaries, expressed through the smallest exterior angle at the boundary.
Furthermore, we show that the rate of approximation on compact subsets inside
the domain is essentially the square of that on the closure. Two standard
applications to the rate of decay for the contour orthogonal polynomials inside
the domain, and to the rate of locally uniform convergence of Fourier series
are also given.


title: No complexity-stability relationship in natural communities

abstract:
  We performed a stability analysis of 119 quantitative food webs which were
compiled using a standard methodology to build Ecopath mass-balance models. Our
analysis reveals that classic descriptors of complexity do not affect stability
in natural food webs. Food web structure, which is non-random in real
communities, reflects another form of complexity that we found influences
dramatically the stability of real communities. We conclude that the occurrence
of complex communities in nature is possible owing to their trophic structure.


title: Spatiality of derivations on the algebra of $\tau$-compact operators

abstract:
  This paper is devoted to derivations on the algebra $S_0(M, \tau)$ of all
$\tau$-compact operators affiliated with a von Neumann algebra $M$ and a
faithful normal semi-finite trace $\tau.$ The main result asserts that every
$t_\tau$-continuous derivation $D:S_0(M, \tau)\rightarrow S_0(M, \tau)$ is
spatial and implemented by a $\tau$-measurable operator affiliated with $M$,
where $t_\tau$ denotes the measure topology on $S_0(M, \tau)$. We also show the
automatic $t_\tau$-continuity of all derivations on $S_0(M, \tau)$ for properly
infinite von Neumann algebras $M$. Thus in the properly infinite case the
condition of $t_\tau$-continuity of the derivation is redundant for its
spatiality.


title:
Microscopic coexistence of a two-component incommensurate spin density
  wave with superconductivity in underdoped NaFe$_{0.983}$Co$_{0.017}$As

abstract:
  We have performed $^{75}$As and $^{23}$Na nuclear magnetic resonance (NMR)
measurements on a single crystal of NaFe$_{0.9835}$Co$_{0.0165}$As and found
microscopic coexistence of superconductivity with a two-component spin density
wave (SDW). Using $^{23}$Na NMR we measured the spatial distribution of local
magnetic fields. The SDW was found to be incommensurate with a major component
having magnetic moment ($\sim0.2\,\mu_B$/Fe) and a smaller component with
magnetic moment ($\sim0.02\,\mu_B$/Fe). Spin lattice relaxation experiments
reveal that this coexistence occurs at a microscopic level.


title: A Riemann-Roch theorem for the noncommutative two torus

abstract:
  We prove the analogue of the Riemann-Roch formula for the noncommutative two
torus $ A_{\theta} = C(\mathbb{T}_{\theta}^2)$ equipped with an arbitrary
translation invariant complex structure and a Weyl factor represented by a
positive element $k\in C^{\infty}(\mathbb{T}_{\theta}^2)$.
  We consider a topologically trivial line bundle equipped with a general
holomorphic structure and the corresponding twisted Dolbeault Laplacians. We
define an spectral triple ($A_{\theta}, \mathcal{H}, D)$ that encodes the
twisted Dolbeault complex of $ A_{\theta}$ and whose index gives the left hand
side of the Riemann-Roch formula.
  Using Connes' pseudodifferential calculus and heat equation techniques, we
explicitly compute the $b_2$ terms of the asymptotic expansion of $\text{Tr}
(e^{-tD^2})$. We find that the curvature term on the right hand side of the
Riemann-Roch formula coincides with the scalar curvature of the noncommutative
torus recently defined and computed in \cite{CM1} and \cite{FK2}.


title: Quantum enigma machines and the locking capacity of a quantum channel

abstract:
  The locking effect is a phenomenon which is unique to quantum information
theory and represents one of the strongest separations between the classical
and quantum theories of information. The Fawzi-Hayden-Sen (FHS) locking
protocol harnesses this effect in a cryptographic context, whereby one party
can encode n bits into n qubits while using only a constant-size secret key.
The encoded message is then secure against any measurement that an eavesdropper
could perform in an attempt to recover the message, but the protocol does not
necessarily meet the composability requirements needed in quantum key
distribution applications. In any case, the locking effect represents an
extreme violation of Shannon's classical theorem, which states that
information-theoretic security holds in the classical case if and only if the
secret key is the same size as the message. Given this intriguing phenomenon,
it is of practical interest to study the effect in the presence of noise, which
can occur in the systems of both the legitimate receiver and the eavesdropper.
This paper formally defines the locking capacity of a quantum channel as the
maximum amount of locked information that can be reliably transmitted to a
legitimate receiver by exploiting many independent uses of a quantum channel
and an amount of secret key sublinear in the number of channel uses. We provide
general operational bounds on the locking capacity in terms of other well-known
capacities from quantum Shannon theory. We also study the important case of
bosonic channels, finding limitations on these channels' locking capacity when
coherent-state encodings are employed and particular locking protocols for
these channels that might be physically implementable.


title: A Jacobi theta series and its transformation laws

abstract:
  We consider a generalization of Jacobi theta series and show that every such
function is a quasi-Jacobi form. Under certain conditions we establish
transformation laws for these functions with respect to the Jacobi group and
prove such functions are Jacobi forms. In establishing these results we
construct other functions which are also Jacobi forms. These results are
motivated by applications in the theory of vertex operator algebras.


title: Jarzynski equality for quantum stochastic maps

abstract:
  Jarzynski equality and related fluctuation theorems can be formulated for
various setups. Such an equality was recently derived for nonunitary quantum
evolutions described by unital quantum operations, i.e., for completely
positive, trace-preserving maps, which preserve the maximally mixed state. We
analyze here a more general case of arbitrary quantum operations on finite
systems and derive the corresponding form of the Jarzynski equality. It
contains a correction term due to nonunitality of the quantum map. Bounds for
the relative size of this correction term are established and they are applied
for exemplary systems subjected to quantum channels acting on a
finite-dimensional Hilbert space.


title: On the Trispectrum of Galileon Inflation

abstract:
  We present a detailed study of the trispectrum of the curvature perturbation
generated within a stable, well defined and predictive theory which comprises
an inflationary phase. In this model the usual shift symmetry is enhanced up to
the so-called Galileon symmetry. The appeal of this type of theories rests on
being unitary and stable under quantum corrections. Furthermore, in the
specific model under consideration here, these properties have been shown to
approximately hold in realistic scenarios which account for curved spacetime
and the coupling with gravity. In the literature, the analysis of the
bispectrum of the curvature perturbation for this theory revealed non-Gaussian
features which are shared by a number of inflationary models, including stable
ones. It is therefore both timely and useful to investigate further and turn to
observables such as the trispectrum. We find that, in a number of specific
momenta configurations, the trispectrum shape-functions present strikingly
different features as compared to, for example, the entire class of the
so-called $P(X,\phi)$ inflationary models.


title: A Particle-Water Based Model for Water Retention Hysteresis

abstract:
  A particle-water discrete element based approach to describe water movement
in partially saturated granular media is presented and tested. Water potential
is governed by both capillary bridges, dominant at low saturations, and the
pressure of entrapped air, dominant at high saturations. The approach captures
the hysteresis of water retention during wetting and drainage by introducing
the local evolution of liquid-solid contact angles at the level of pores and
grains. Extensive comparisons against experimental data are presented. While
these are made without the involvement of any fitting parameters, the method
demonstrates relative high success by achieving a correlation coefficient of at
least 82%, and mostly above 90%. For the tested materials with relatively
mono-disperse grain size, the hysteresis of water retention during cycles of
wetting and drainage has been shown to arise from the dynamics of solid-liquid
contact angles as a function of local liquid volume changes.


title:
Microscopic approach to the nucleon-nucleon effective interaction and
  nucleon-nucleon scattering in symmetric and isospin-asymmetric nuclear matter

abstract:
  After reviewing our microscopic approach to nuclear and neutron-rich matter,
we focus on how nucleon-nucleon scattering is impacted by the presence of a
dense hadronic medium, with special emphasis on the case where neutron and
proton densities are different. We discuss in detail medium and isospin
asymmetry effects on the total elastic cross section and the mean free path of
a neutron or a proton in isospin-asymmetric nuclear matter. We point out that
in-medium cross sections play an important role in heavy-ion simulations aimed
at extracting constraints on the symmetry potential. We argue that medium and
isospin dependence of microscopic cross sections are the results of a complex
balance among various effects, and cannot be simulated with a simple
phenomenological model.


title: Solar Activity during Two Millennia as Estimated from Annual Tree Rings

abstract:
  The relationship between solar activity and the global climate is not only an
academically interesting issue, but also an important problem for human beings.
Lean and Rind have analyzed a considerable amount of climate data from around
the world from 1889 to 2006. According to their analysis, the global effect was
estimated to be 0.17 plus-minus 0.01K between the solar maximum and minimum.
However, they noticed that the effect strongly appeared in the zones between
70N and 30N, and between 25S and 50S. At its peak latitude (near 40), the
effect was estimated to be 0.5 K. Therefore, we analyzed a tree that survived
at the Murooji temple in Nara prefecture (34d32mN, 136d2mE) Japan, for 391
years.
  Quite surprisingly, Fourier analysis of the annual growth rate identified two
cycles with periodicities of 12 and 25 years during the Maunder minimum. We
have continued the analysis, using different samples from the Nagusa shrine in
Hyogo Prefecture, Itayanagi City, Aomori Prefecture, Japan, and from Yaku
Island in Kyusyu, Japan. An evidence of solar activity was found in all of the
samples. In particular, we have discovered a correlation between Swiss glacier
fluctuation and the growth rate of the Yaku tree ring.


title: Interplanetary spacecraft navigation using pulsars

abstract:
  We demonstrate how observations of pulsars can be used to help navigate a
spacecraft travelling in the solar system. We make use of archival observations
of millisecond pulsars from the Parkes radio telescope in order to demonstrate
the effectiveness of the method and highlight issues, such as pulsar spin
irregularities, which need to be accounted for. We show that observations of
four millisecond pulsars every seven days using a realistic X-ray telescope on
the spacecraft throughout a journey from Earth to Mars can lead to position
determinations better than approx. 20km and velocity measurements with a
precision of approx. 0.1m/s.


title: Measurement of High-Energy Solar Neutrons with SEDA-FIB onboard the ISS

abstract:
  A new type of solar neutron detector (SEDA-FIB) was launched on board the
Space Shuttle Endeavor on July 16 2009, and began collecting data at the
International Space Station (ISS) on August 25 2009. This paper summarizes four
years of observations with the solar neutron detector SEDA-FIB (Space
Environment Data Acquisition using the FIBer detector). The solar neutron
detector FIB can determine both the energy and arrival direction of solar
neutrons.
  In this paper, we first present the angular distribution of neutron induced
protons obtained in Monte Carlo simulations. The results are compared with the
experimental results. Then we provide the angular distribution of background
neutrons during one full orbit of the ISS (90 minutes). Next, the angular
distribution of neutrons during the flare onset time from 20:02 to 20:10 UT on
March 7 2011 is presented. It is compared with the distribution when a solar
flare is not occurring. Observed solar neutrons possibly originated from the
M-class solar flares that occurred on March 7 (M3.7), June 7 (M2.5), September
24 (M3.0) (weak signal) and November 3 (X1.9) of 2011 and January 23 of 2012
(M8.7). This marked the first time that neutrons have been observed from
M-class solar flares. A possible interpretation of the neutron production
process will be also provided.


title:
Homology and Bisimulation of Asynchronous Transition Systems and Petri
  Nets

abstract:
  Homology groups of labelled asynchronous transition systems and Petri nets
are introduced. Examples of computing the homology groups are given. It is
proved that if labelled asynchronous transition systems are bisimulation
equivalent, then they have isomorphic homology groups. A method of constructing
a Petri net with given homology groups is found.


title: Domination game: effect of edge- and vertex-removal

abstract:
  The domination game is played on a graph $G$ by two players, named Dominator
and Staller. They alternatively select vertices of $G$ such that each chosen
vertex enlarges the set of vertices dominated before the move on it.
Dominator's goal is that the game is finished as soon as possible, while
Staller wants the game to last as long as possible. It is assumed that both
play optimally. Game 1 and Game 2 are variants of the game in which Dominator
and Staller has the first move, respectively. The game domination number
$\gamma_g(G)$, and the Staller-start game domination number $\gamma_g'(G)$, is
the number of vertices chosen in Game 1 and Game 2, respectively. It is proved
that if $e\in E(G)$, then $|\gamma_g(G) - \gamma_g(G-e)| \le 2$ and
$|\gamma_g'(G) - \gamma_g'(G-e)| \le 2$, and that each of the possibilities
here is realizable by connected graphs $G$ for all values of $\gamma_g(G)$ and
$\gamma_g'(G)$ larger than 5. For the remaining small values it is either
proved that realizations are not possible or realizing examples are provided.
It is also proved that if $v\in V(G)$, then $\gamma_g(G) - \gamma_g(G-v) \le 2$
and $\gamma_g'(G) - \gamma_g'(G-v) \le 2$. Possibilities here are again
realizable by connected graphs $G$ in almost all the cases, the exceptional
values are treated similarly as in the edge-removal case.


title:
How ions in solution can change the sign of the critical Casimir
  potential

abstract:
  We show that hydrophilic ions present in a confined, near-critical aqueous
mixture can lead to an attraction between like charge surfaces with opposing
preferential adsorption of the two species of the mixture, even though the
corresponding Casimir potential in uncharged systems is repulsive. This
prediction agrees with recent experiment [Nellen {\it{et al.}}, Soft
Matter{\bf{80}}, 061143 (2011)]. We also show that oppositely charged
hydrophobic surfaces can repel each other, although the Casimir potential
between uncharged surfaces with like preferential adsorption (selectivity) is
attractive. This behavior is expected when the electrostatic screening length
is larger than the correlation length, and one of the confining surfaces is
strongly selective and weakly charged, whereas the other confining surface is
weakly selective and strongly charged. The Casimir potential can change sign
because the hydrophilic ions near the weakly hydrophobic surface can
overcompensate the effect of hydrophobicity, and this surface can act as a
hydrophilic one. We also predict a more attractive interaction between
hydrophilic surfaces and a more repulsive interaction between hydrophobic
surfaces than given by the sum of the Casimir and Deby-H\"uckel potentials. Our
theory is derived systematically from a microscopic approach, and combines the
Landau-type and Debye-H\"uckel theories with an additional contribution of an
entropic origin.


title: How to induce multiple delays in coupled chaotic oscillators?

abstract:
  Lag synchronization is a basic phenomenon in mismatched coupled systems,
delay coupled systems and time-delayed systems. It is characterized by a lag
configuration that establishes a unique time shift between all the state
variables of the coupled systems. In this report, an attempt is made how to
induce multiple lag configurations in coupled systems when different pairs of
state variables attain different time shift. A design of coupling is presented
to realize this multiple lag synchronization. Numerical illustration is given
using examples of the R\"ossler system and the slow-fast Hindmarsh-Rose neuron
model. The multiple lag scenario is physically realized in an electronic
circuit of two Sprott systems.


title:
A convex pseudo-likelihood framework for high dimensional partial
  correlation estimation with convergence guarantees

abstract:
  Sparse high dimensional graphical model selection is a topic of much interest
in modern day statistics. A popular approach is to apply l1-penalties to either
(1) parametric likelihoods, or, (2) regularized regression/pseudo-likelihoods,
with the latter having the distinct advantage that they do not explicitly
assume Gaussianity. As none of the popular methods proposed for solving
pseudo-likelihood based objective functions have provable convergence
guarantees, it is not clear if corresponding estimators exist or are even
computable, or if they actually yield correct partial correlation graphs. This
paper proposes a new pseudo-likelihood based graphical model selection method
that aims to overcome some of the shortcomings of current methods, but at the
same time retain all their respective strengths. In particular, we introduce a
novel framework that leads to a convex formulation of the partial covariance
regression graph problem, resulting in an objective function comprised of
quadratic forms. The objective is then optimized via a coordinate-wise
approach. The specific functional form of the objective function facilitates
rigorous convergence analysis leading to convergence guarantees; an important
property that cannot be established using standard results, when the dimension
is larger than the sample size, as is often the case in high dimensional
applications. These convergence guarantees ensure that estimators are
well-defined under very general conditions, and are always computable. In
addition, the approach yields estimators that have good large sample properties
and also respect symmetry. Furthermore, application to simulated/real data,
timing comparisons and numerical convergence is demonstrated. We also present a
novel unifying framework that places all graphical pseudo-likelihood methods as
special cases of a more general formulation, leading to important insights.


title:
NMR and NQR Studies on Non-centrosymmetric Superconductors Re7B3,
  LaBiPt, and BiPd

abstract:
  We report the nuclear magnetic resonance (NMR) and nuclear quadrupole
resonance (NQR) measurements for non-centrosymmetric superconductors Re7B3,
LaBiPt, and BiPd containing heavy elements. For all three compounds, the
spin-lattice relaxation rate 1/T1 shows a coherence peak just below Tc and
decreases exponentially at low temperatures, which indicates that an isotropic
superconducting gap is dominant in these compounds. In BiPd, the height of the
coherence peak just below Tc is much suppressed, which suggests that there
exists a substantial component of gap with nodes in this compound. Our results
indicate that heavy element is not the only factor, but the extent of inversion
symmetry breaking is also important to induce a large spin-orbit coupling and
an unconventional superconducting state.


title: Blocked-braid Groups

abstract:
  We introduce and study a family of groups $\mathbf{BB}_n$, called the
blocked-braid groups, which are quotients of Artin's braid groups
$\mathbf{B}_n$, and have the corresponding symmetric groups $\Sigma_n$ as
quotients. They are defined by adding a certain class of geometrical
modifications to braids. They arise in the study of commutative Frobenius
algebras and tangle algebras in braided strict monoidal categories. A
fundamental equation true in $\mathbf{BB}_n$ is Dirac's Belt Trick; that
torsion through $4\pi$ is equal to the identity. We show that $\mathbf{BB}_n$
is finite for $n=1,2$ and 3 but infinite for $n>3$.


title:
The early phase of multiple proto-stellar system emerged from collapse
  of molecular cloud under various initial thermal states

abstract:
  An attempt is made here to revisit structure formation in a proto-stellar
cloud during the early phase of evolution. Molecular cloud subjected to a set
of various initial conditions in terms of initial temperature and amplitude of
azimuthal density perturbation is investigated numerically. Special emphasis
remained on the analysis of ring and spiral type instabilities that have shown
dependence on certain initial conditions chosen for a rotating solar mass cloud
of molecular hydrogen. Generally, a star forming hydrogen gas is considered to
be initially at 10K. We have found that a possible oscillation around this
typical value can affect the fate of a collapsing cloud in terms of its
evolving structural properties leading to proto-star formation. We explored the
initial temperature range of cloud between 8K to 12K and compared physical
properties of each within the first phase of proto-star formation. We suggest
that the spiral structures are more likely to form in strongly perturbed
molecular cores that initiate their phase of collapse from temperatures below
10K. Whereas, cores with initial temperatures above 10K develop, instead of
spiral, a ring type structure which subsequently experiences the fragmentation.
A transition from spiral to ring instability can be observed at a typical
initial temperature of 10K.


title: Frozen Gaussian quantum discord in photonic crystal cavity array system

abstract:
  Protecting quantum correlation from decoherence is one of the crucial issues
in quantum information processing. It has been commonly recognized that any
initial quantum correlation of a composite system diminishes asymptotically or
abruptly to zero under local Markovian decoherence. Here we show that, contrary
to this recognition, a noticeable Gaussian quantum discord of a
continuous-variable bipartite system can be frozen in the steady state in the
non-Markovian dynamics if each of the subsystems forms a localized mode with
its local reservoir. The condition for this frozen quantum discord can be
reached by appropriately engineering the structure of the reservoirs. The
possible realization of our results in a coupled cavity array system formed by
a photonic crystal is proposed.


title: Robust SOS-Convex Polynomial Programs: Exact SDP Relaxations

abstract:
  This paper studies robust solutions and semidefinite linear programming (SDP)
relaxations of a class of convex polynomial programs in the face of data
uncertainty. The class of convex programs, called robust SOS-convex programs,
includes robust quadratically constrained convex programs and robust separable
convex polynomial programs. It establishes sums of squares polynomial
representations characterizing robust solutions and exact SDP-relaxations of
robust SOS-convex programs under various commonly used uncertainty sets. In
particular, the results show that the polytopic and ellipsoidal uncertainty
sets, that allow second-order cone re-formulations of robust quadratically
constrained programs, continue to permit exact SDP-relaxations for a broad
class of robust SOS-convex programs. They also yield exact second-order cone
relaxation for robust quadratically constrained programs.


title: ALMA Nutator Design and Preliminary Performance

abstract:
  We report the past two years of collaboration between the different actors on
the ALMA nutator. Building on previous developments, the nutator has seen
changes in much of the design. A high-modulus carbon fiber structure has been
added on the back of the mirror in order to transfer the voice coils forces
with less deformation, thus reducing delay problems due to flexing. The
controller is now an off-the-shelf National Instrument NI-cRIO, and the
amplifier a class D servo drive from Advanced Motion Controls, with high peak
power able to drive the coils at 300 Volts DC. The stow mechanism has been
totally redesigned to improve on the repeatability and precision of the stow
position, which is also the reference for the 26 bits Heidenhain encoders. This
also improves on the accuracy of the stow position with wind loading. Finally,
the software, written largely with National Instrument's LabView, has been
developed. We will discuss these changes and the preliminary performances
achieved to date. Keywords: ALMA, nutator, class D, high-modulus carbon fiber.


title:
An elementary proof for that all unoriented spanning surfaces of a link
  are related by attaching/deleting tubes and M\"{o}bius bands

abstract:
  Gordon and Litherland showed that all compact, unoriented, possibly
non-orientable surfaces in $S^3$ bounded by a link are realted by
attaching/deleting tubes and half twisted bands. In this note we give an
elementary proof for this result.


title:
YSO accretion shocks: magnetic, chromospheric or stochastic flow effects
  can suppress fluctuations of X-ray emission

abstract:
  Context. Theoretical arguments and numerical simulations of radiative shocks
produced by the impact of the accreting gas onto young stars predict
quasi-periodic oscillations in the emitted radiation. However, observational
data do not show evidence of such periodicity. Aims. We investigate whether
physically plausible perturbations in the accretion column or in the
chromosphere could disrupt the shock structure influencing the observability of
the oscillatory behavior. Methods. We performed local 2D magneto-hydrodynamical
simulations of an accretion shock impacting a chromosphere, taking optically
thin radiation losses and thermal conduction into account. We investigated the
effects of several perturbation types, such as clumps in the accretion stream
or chromospheric fluctuations, and also explored a wide range of plasma-\beta
values. Results. In the case of a weak magnetic field, the post-shock region
shows chaotic motion and mixing, smoothing out the perturbations and retaining
a global periodic signature. On the other hand, a strong magnetic field
confines the plasma in flux tubes, which leads to the formation of fibrils that
oscillate independently. Realistic values for the amplitude, length, and time
scales of the perturbation are capable of bringing the fibril oscillations out
of phase, suppressing the periodicity of the emission. Conclusions. The
strength of a locally uniform magnetic field in YSO accretion shocks determines
the structure of the post-shock region, namely, whether it will be somewhat
homogeneous or if it will split up to form a collection of fibrils. In the
second case, the size and shape of the fibrils is found to depend strongly on
the plasma-\beta value but not on the perturbation type. Therefore, the actual
value of the protostellar magnetic field is expected to play a critical role in
the time dependence of the observable emission.


title:
Low-dimensional pairing fluctuations and pseudogapped photoemission
  spectrum in a trapped two-dimensional Fermi gas

abstract:
  We investigate strong-coupling properties of a trapped two-dimensional normal
Fermi gas. Within the framework of a combined $T$-matrix theory with the local
density approximation, we calculate the local density of states, as well as the
photoemission spectrum, to see how two-dimensional pairing fluctuations affect
these single-particle quantities. In the BCS (Bardeen-Cooper-Schrieffer)-BEC
(Bose-Einstein condensation) crossover region, we show that the local density
of states exhibits a dip structure in the trap center, which is more remarkable
than the three-dimensional case. This pseudogap phenomenon is found to
naturally lead to a double peak structure in the photoemission spectrum. The
peak-to-peak energy of the spectrum at p=0 agrees well with the recent
experiment on a two-dimensional 40K Fermi gas [M. Feld, et al., Nature 480, 75
(2011)]. Since pairing fluctuations are sensitive to the dimensionality of a
system, our results would be useful for the study of many-body physics in the
BCS-BEC crossover regime of a two-dimensional Fermi gas.


title: Neutron star high mass binaries as the origin of SGR/AXP

abstract:
  A close high-mass binary system consisting of a neutron star (NS) and a
massive OB supergiant companion is expected to lead to a TZO structure, which
consists of a NS core and a stellar envelope. We use the scenario machine
program to calculate the formation tracks of TZOs in close high mass NS
binaries and their subsequent evolution. We propose and demonstrate that the
explosion and instant contraction of a TZO structure leave its stellar remnant
as a soft gamma ray repeater and an anomalous X-ray pulsar respectively.


title: A Note On Transversals

abstract:
  Let $G$ be a finite group and $H$ a core-free subgroup of $G$. We will show
that if there exists a solvable, generating transversal of $H$ in $G$, then $G$
is a solvable group. Further, if $S$ is a generating transversal of $H$ in $G$
and $S$ has order 2 invariant sub right loop $T$ such that the quotient $S/T$
is a group. Then $H$ is an elementary abelian 2-group.


title: Clustering Algorithm for Gujarati Language

abstract:
  Natural language processing area is still under research. But now a day it is
on platform for worldwide researchers. Natural language processing includes
analyzing the language based on its structure and then tagging of each word
appropriately with its grammar base. Here we have 50,000 tagged words set and
we try to cluster those Gujarati words based on proposed algorithm, we have
defined our own algorithm for processing. Many clustering techniques are
available Ex. Single linkage, complete, linkage,average linkage, Hear no of
clusters to be formed are not known, so it is all depends on the type of data
set provided . Clustering is preprocess for stemming . Stemming is the process
where root is extracted from its word. Ex. cats= cat+S, meaning. Cat: Noun and
plural form.


title: Functions dividing their Hessian determinants and affine spheres

abstract:
  The nonzero level sets of a homogeneous, logarithmically homogeneous, or
translationally homogeneous function are affine spheres if and only if the
Hessian determinant of the function is a multiple of a power or an exponential
of the function. In particular, the nonzero level sets of a homogeneous
polynomial are proper affine spheres if some power of it equals a nonzero
multiple of its Hessian determinant. The relative invariants of real forms of
regular irreducible prehomogeneous vector spaces yield many such polynomials
which are moreover irreducible. For example, the nonzero level sets of the
Cayley hyperdeterminant are affine spheres.


title: Dual Halos and Formation of Early-Type Galaxies

abstract:
  We present a determination of the two-dimensional shape parameters of the
blue and red globular cluster systems (GCSs) in a large number of elliptical
galaxies and lenticular galaxies (early-type galaxies, called ETGs). We use a
homogeneous data set of the globular clusters in 23 ETGs obtained from the
HST/ACS Virgo Cluster Survey. The position angles of both blue and red GCSs
show a correlation with those of the stellar light distribution, showing that
the major axes of the GCSs are well aligned with those of their host galaxies.
However, the shapes of the red GCSs show a tight correlation with the stellar
light distribution as well as with the rotation property of their host
galaxies, while the shapes of the blue GCSs do much less. These provide clear
geometric evidence that the origins of the blue and red globular clusters are
distinct and that ETGs may have dual halos: a blue (metal-poor) halo and a red
(metal-rich) halo. These two halos show significant differences in metallicity,
structure, and kinematics, indicating that they are formed in two
distinguishable ways. The red halos might have formed via dissipational
processes with rotation, while the blue halos are through accretion.


title:
Star graphs induce tetrad correlations: for Gaussian as well as for
  binary variables

abstract:
  Tetrad correlations were obtained historically for Gaussian distributions
when tasks are designed to measure an ability or attitude so that a single
unobserved variable may generate the observed, linearly increasing dependences
among the tasks. We connect such generating processes to a particular type of
directed graph, the star graph, and to the notion of traceable regressions.
Tetrad correlation conditions for the existence of a single latent variable are
derived. These are needed for positive dependences not only in joint Gaussian
but also in joint binary distributions. Three applications with binary items
are given.


title: The low-mass end of the IMF

abstract:
  The rapid advances in infrared detector technology over the past decades have
impelled the development of wide-field instruments, and shaped our view of the
cold universe. Large scale surveys in our Galaxy have discovered hundreds of
brown dwarfs enabling the characterisation of the mass function in the
substellar regime. I will review the most recent observational results
concerning the substellar IMF derived in star forming regions, open clusters,
and the field, that must be reproduced and explained by any successful star
formation theory.


title:
A Numerov-Crank-Nicolson-Strang scheme with discrete transparent
  boundary conditions for the Schr\"odinger equation on a semi-infinite strip

abstract:
  We consider an initial-boundary value problem for a 2D time-dependent
Schr\"odinger equation on a semi-infinite strip. For the Numerov-Crank-Nicolson
finite-difference scheme with discrete transparent boundary conditions, the
Strang-type splitting with respect to the potential is applied. For the
resulting method, the uniqueness of a solution and the uniform in time
$L^2$-stability (in particular, $L^2$-conservativeness) are proved. Due to the
splitting, an effective direct algorithm using FFT in the direction
perpendicular to the strip is developed to implement the splitting method for
general potential. Numerical results on the tunnel effect for smooth and
rectangular barriers together with the practical error analysis on refining
meshes are included as well.


title:
Density estimates for differential equations of second order satisfying
  a weak Hoermander condition

abstract:
  We prove an extension of Hoermander's classical result on hypoelliptic second
order equations, where the coefficients of the related vector fields are
globally Lipschitz and satisfy the classical Hoermander condition on a dense
set while the density still exists in a classical sense. Furthermore,
Hoermander's classical result and related density estimates based on Malliavin
calculus are recovered from an analytical point of view.


title: Generic representations of wild quivers

abstract:
  We show that any generic representation of a wild connected directed quiver
is the union of its subrepresentations of finite length which are regular. As a
consequence, we see that the direct limit closure of the preprojective
component does not contain any generic module.


title: A Note on Co-Maximal Ideal Graph of Commutative Rings

abstract:
  Let $R$ be a commutative ring with unity. The co-maximal ideal graph of $R$,
denoted by $\Gamma(R)$, is a graph whose vertices are the proper ideals of $R$
which are not contained in the Jacobson radical of $R$, and two vertices $I_1$
and $I_2$ are adjacent if and only if $I_1 + I_2 = R$. We classify all
commutative rings whose co-maximal ideal graphs are planar. In 2012 the
following question was posed: If $\Gamma(R)$ is an infinite star graph, can $R$
be isomorphic to the direct product of a field and a local ring? In this paper,
we give an affirmative answer to this question.


title:
Hermite-Hadamard type inequalities for harmonically ({\alpha},m)-convex
  functions

abstract:
  The author introduces the concept of harmonically ({\alpha},m)-convex
functions and establishes some Hermite-Hadamard type inequalities of these
classes of functions.


title:
Entanglement-assisted capacities of time-correlated amplitude-damping
  channel

abstract:
  We calculate the information capacities of a time-correlated
amplitude-damping channel, provided the sender and receiver share prior
entanglement. Our analytical results show that the noisy channel with zero
capacity can transmit information if it has finite memory. The capacities
increase as the memory increases attaining maximum value for perfect memory
channel.


title: Racks and blocked braids

abstract:
  In the paper Blocked-braid Groups, submitted to Applied Categorical
Structures, the present authors together with Davide Maglia introduced the
blocked-braid groups BB_n on n strands, and proved that a blocked torsion has
order either 2 or 4. We conjectured that the order was actually 4 but our
methods in that paper, which involved introducing for any group G a braided
monoidal category of tangled relations, were inadequate to demonstrate this
fact. Subsequently Davide Maglia in unpublished work investigated exactly what
part of the structure and properties of a group G are needed to permit the
construction of a braided monoidal category with a tangle algebra and was able
to distinguish blocked two-torsions from the identity.
  In this paper we present a simplification of his answer, which turns out to
be related to the notion of rack. We show that if G is a rack then there is a
braided monoidal category TRel_G generalizing that of the above paper. Further
we introduce a variation of the notion of rack which we call irack which yields
a tangle algebra in TRel_G. Iracks are in particular racks but have in addition
to the operations abstracting group conjugation also a unary operation
abstracting group inverse. Using iracks we obtain new invariants for tangles
and blocked braids permitting us to present a proof of Maglia's result that a
blocked double torsion is not the identity.
  This work was presented at the Conference in Memory of Aurelio Carboni,
Milan, 24-26 June 2013.


title:
Boosting the performance of the ASTRI SST-2M prototype: reflective and
  anti-reflective coatings

abstract:
  ASTRI is a Flagship Project of the Italian Ministry of Education, University
and Research, led by the Italian National Institute of Astrophysics, INAF. One
of the main aims of the ASTRI Project is the design, construction and
verification on-field of a dual mirror (2M) end-to-end prototype for the Small
Size Telescope (SST) envisaged to become part of the Cherenkov Telescope Array.
The ASTRI SST-2M prototype adopts the Schwarzschild-Couder design, and a camera
based on SiPM (Silicon Photo Multiplier); it will be assembled at the INAF
astronomical site of Serra La Nave on mount Etna (Catania, Italy) within mid
2014, and will start scientific validation phase soon after. The peculiarities
of the optical design and of the SiPM bandpass pushed towards specifically
optimized choices in terms of reflective coatings for both the primary and the
secondary mirror. In particular, multi-layer dielectric coatings, capable of
filtering out the large Night Sky Background contamination at wavelengths
$\lambda \gtrsim 700$ nm have been developed and tested, as a solution for the
primary mirrors. Due to the conformation of the ASTRI SST-2M camera, a
reimaging system based on thin pyramidal light guides could be optionally
integrated aiming to increase the fill factor. An anti-reflective coating
optimized for a wide range of incident angles faraway from normality was
specifically developed to enhance the UV-optical transparency of these
elements. The issues, strategy, simulations and experimental results are
thoroughly presented.


title:
Critical weak immersed Surfaces within Sub-manifolds of the
  Teichm\"uller Space

abstract:
  We prove that the critical points of various energies such as the area, the
Willmore energy, the frame energy for tori...etc among possibly branched
immersions constrained to evolve within a smooth sub-manifold of the
Teichm\"uller space satisfy the corresponding constrained Euler Lagrange
equation. We deduce that critical points of the Willmore energy or the frame
energy for tori are smooth analytic surfaces, away possibly from isolated
branched points, under the condition that either the genus is at most 2 or if
the sub-manifold does not intersect the subspace of hyper-elliptic points.
Using a compactness result from a previous work of the author, we can conclude
that each closed sub-manifold of the Teichm\"uller space, including points,
under the previous assumptions, posses a possibly branched smooth Willmore
minimizer satisfying the conformal-constrained Willmore equation.


title:
A completely monotonic function involving the gamma and tri-gamma
  functions

abstract:
  In the paper the author provides necessary and sufficient conditions on $a$
for the function $\frac{1}{2}\ln(2\pi)-x+\bigl(x-\frac{1}{2}\bigr)\ln
x-\ln\Gamma(x)+\frac1{12}{\psi'(x+a)}$ and its negative to be completely
monotonic on $(0,\infty)$, where $a\ge0$ is a real number, $\Gamma(x)$ is the
classical gamma function, and $\psi(x)=\frac{\Gamma'(x)}{\Gamma(x)}$ is the
di-gamma function. As applications, some known results and new inequalities are
derived.


title: Bad fields with torsion

abstract:
  We extend the construction of bad fields of characteristic zero to the case
of arbitrary prescribed divisible green torsion.


title: Divergence for s-concave and log concave functions

abstract:
  We prove new entropy inequalities for log concave and s-concave functions
that strengthen and generalize recently established reverse log Sobolev and
Poincare inequalities for such functions. This leads naturally to the concept
of f-divergence and, in particular, relative entropy for s-concave and log
concave functions. We establish their basic properties, among them the affine
invariant valuation property. Applications are given in the theory of convex
bodies.