title:
Estimating the ground state energy of the Schr\"odinger equation for
  convex potentials

abstract:
  In 2011, the fundamental gap conjecture for Schr\"odinger operators was
proven. This can be used to estimate the ground state energy of the
time-independent Schr\"odinger equation with a convex potential and relative
error \epsilon. Classical deterministic algorithms solving this problem have
cost exponential in the number of its degrees of freedom d. We show a quantum
algorithm, that is based on a perturbation method, for estimating the ground
state energy with relative error \epsilon. The cost of the algorithm is
polynomial in d and \epsilon^{-1}, while the number of qubits is polynomial in
d and \log\epsilon^{-1}. In addition, we present an algorithm for preparing a
quantum state that overlaps within 1-\delta, \delta \in (0,1), with the ground
state eigenvector of the discretized Hamiltonian. This algorithm also
approximates the ground state with relative error \epsilon. The cost of the
algorithm is polynomial in d, \epsilon^{-1} and \delta^{-1}, while the number
of qubits is polynomial in d, \log\epsilon^{-1} and \log\delta^{-1}.


title: Labelled seeds and the mutation group

abstract:
  We study the set S of labelled seeds of a cluster algebra of rank n inside a
field F as a homogeneous space for the group M_n of (globally defined)
mutations and relabellings. Regular equivalence relations on S are associated
to subgroups W of Aut_{M_n}(S), and we thus obtain groupoids W \ S. We show
that for two natural choices of equivalence relation, the corresponding groups
W^c and W^+ act on F, and the groupoids W^c \ S and W^+ \ S on the model field
K=Q(x_1,...,x_n). The groupoid W^+ \ S is equivalent to Fock-Goncharov's
cluster modular groupoid. Moreover, W^c is isomorphic to the group of cluster
automorphisms, and W^+ to the subgroup of direct cluster automorphisms, in the
sense of Assem-Schiffler-Shramchenko. We also prove that, for mutation classes
whose seeds have mutation finite quivers, the stabilizer of a labelled seed
under M_n determines the quiver of the seed up to 'similarity', meaning up to
taking opposites of some of the connected components. Consequently, the
subgroup W^c is the entire automorphism group of S in these cases.


title:
Search for the X(4140) state in B+->J/psi phi K+ decays with the D0
  detector

abstract:
  We investigate the decay B^+ -> J/psi phi K^+ in a search for the X(4140)
state, a narrow threshold resonance in the J/psi phi system. The data sample
corresponds to an integrated luminosity of 10.4 fb^{-1} of ppbar collisions at
sqrt s =1.96 TeV collected by the D0 experiment at the Fermilab Tevatron
collider. We observe a mass peak with a statistical significance of 3.1
standard deviations and measure its invariant mass to be M=4159.0 +-.3 (stat)
+- 6.6 (syst) MeV and its width to be Gamma= 19.9+-12.6 (stat)}^{+1.0}_{-8.0}
(syst) MeV. Identifying this mass peak as the X(4140), we measure, for M(J/psi
phi) <4.59 GeV, the relative branching fraction B_rel= B(B^+ -> X(4140) K^+)/
B(B^+ ->J/psi phi K^+) to be 21+-8 (stat) +- 4 (syst)%. In addition, the data
can accommodate the presence of a second enhancement at a mass of 4328.5+- 12.0
MeV.


title:
Exact inversion of the conical Radon transform with a fixed opening
  angle

abstract:
  We study a new class of Radon transforms defined on circular cones called the
conical Radon transform. In $\mathbb{R}^3$ it maps a function to its surface
integrals over circular cones, and in $\mathbb{R}^2$ it maps a function to its
integrals along two rays with a common vertex. Such transforms appear in
various mathematical models arising in medical imaging, nuclear industry and
homeland security. This paper contains new results about inversion of conical
Radon transform with fixed opening angle and vertical central axis in
$\mathbb{R}^2$ and $\mathbb{R}^3$. New simple explicit inversion formulae are
presented in these cases. Numerical simulations were performed to demonstrate
the efficiency of the suggested algorithm in 2D.


title:
The narrow X-ray tail and double H-alpha tails of ESO 137-002 in Abell
  3627

abstract:
  We present the analysis of a deep Chandra observation of a ~2L_* late-type
galaxy, ESO 137-002, in the closest rich cluster A3627. The Chandra data reveal
a long (>40 kpc) and narrow tail with a nearly constant width (~3 kpc) to the
southeast of the galaxy, and a leading edge ~1.5 kpc from the galaxy center on
the upstream side of the tail. The tail is most likely caused by the nearly
edge-on stripping of ESO 137-002's ISM by ram pressure, compared to the nearly
face-on stripping of ESO 137-001 discussed in our previous work. Spectral
analysis of individual regions along the tail shows that the gas throughout it
has a rather constant temperature, ~1 keV, very close to the temperature of the
tails of ESO 137-001, if the same atomic database is used. The derived gas
abundance is low (~0.2 solar with the single-kT model), an indication of the
multiphase nature of the gas in the tail. The mass of the X-ray tail is only a
small fraction (<5%) of the initial ISM mass of the galaxy, suggesting that the
stripping is most likely at an early stage. However, with any of the single-kT,
double-kT and multi-kT models we tried, the tail is always "over-pressured"
relative to the surrounding ICM, which could be due to the uncertainties in the
abundance, thermal vs. non-thermal X-ray emission, or magnetic support in the
ICM. The H-alpha data from SOAR show a ~21 kpc tail spatially coincident with
the X-ray tail, as well as a secondary tail (~12 kpc long) to the east of the
main tail diverging at an angle of ~23 degrees and starting at a distance of
~7.5 kpc from the nucleus. At the position of the secondary H-alpha tail, the
X-ray emission is also enhanced at the ~2 sigma level. We compare the tails of
ESO 137-001 and ESO 137-002, and also compare the tails to simulations. Both
the similarities and differences of the tails pose challenges to the
simulations. Several implications are briefly discussed.


title: What does strong subadditivity tell us about black holes?

abstract:
  It has been argued that small corrections to evolution arising from
non-geometric effects can resolve the information paradox. We can get such
effects, for example, from subleading saddle points in the Euclidean path
integral. But an inequality derived in 2009 using strong sub-additivity showed
that such corrections {\it cannot} solve the problem. As a result we sharpen
the original Hawking puzzle: we must either have (A) new (nonlocal) physics or
(B) construct hair at the horizon. We get correspondingly different approaches
to resolving the AMPS puzzle. Traditional complementarity assumes (A); here we
require that the AMPS experiment measures the correct vacuum entanglement of
Hawking modes, and invoke nonlocal $A=R_B$ type effects to obtain unitarity of
radiation. Fuzzball complementarity is in category (B); here the AMPS
measurement is outside the validity of the approximation required to obtain the
complementary description, and a effective regular horizon arises only for
freely infalling observers with energies $E\gg T$.


title:
Should I Stay or Should I Go: Coordinating Biological Needs with
  Continuously-updated Assessments of the Environment

abstract:
  This paper presents Wanderer, a model of how autonomous adaptive systems
coordinate internal biological needs with moment-by-moment assessments of the
probabilities of events in the external world. The extent to which Wanderer
moves about or explores its environment reflects the relative activations of
two competing motivational sub-systems: one represents the need to acquire
energy and it excites exploration, and the other represents the need to avoid
predators and it inhibits exploration. The environment contains food,
predators, and neutral stimuli. Wanderer responds to these events in a way that
is adaptive in the short turn, and reassesses the probabilities of these events
so that it can modify its long term behaviour appropriately. When food appears,
Wanderer be-comes satiated and exploration temporarily decreases. When a
predator appears, Wanderer both decreases exploration in the short term, and
becomes more "cautious" about exploring in the future. Wanderer also forms
associations between neutral features and salient ones (food and predators)
when they are present at the same time, and uses these associations to guide
its behaviour.


title: Next-to-leading order QCD corrections to five jet production at the LHC

abstract:
  We present theoretical predictions for five jet production in proton-proton
collisions at next-to-leading order accuracy in QCD. Inclusive as well as
differential observables are studied for collision energies of 7 and 8 TeV. In
general the next-to-leading order corrections stabilize the theoretical
predictions with respect to scale variations. In case of the inclusive jet
cross sections, we compare with experimental data where possible and find
reasonable agreement. We observe that the four-to-three and five-to-four jet
ratios show better perturbative convergence than the known three-to-two ratio
and are promising candidates for future alpha_s measurements. Furthermore, we
present a detailed analysis of uncertainties related to parton distribution
functions. The full colour virtual matrix elements used in the computation were
obtained with the NJet package, a publicly available library for the evaluation
of one-loop amplitudes in massless QCD.


title: The resource theory of informational nonequilibrium in thermodynamics

abstract:
  We review recent work on the foundations of thermodynamics in the light of
quantum information theory. We adopt a resource-theoretic perspective, wherein
thermodynamics is formulated as a theory of what agents can achieve under a
particular restriction, namely, that the only state preparations and
transformations that they can implement for free are those that are thermal at
some fixed temperature. States that are out of thermal equilibrium are the
resources. We consider the special case of this theory wherein all systems have
trivial Hamiltonians (that is, all of their energy levels are degenerate). In
this case, the only free operations are those that add noise to the system (or
implement a reversible evolution) and the only nonequilibrium states are states
of informational nonequilibrium, that is, states that deviate from the
maximally mixed state. The degree of this deviation we call the state's
nonuniformity; it is the resource of interest here, the fuel that is consumed,
for instance, in an erasure operation. We consider the different types of state
conversion: exact and approximate, single-shot and asymptotic, catalytic and
noncatalytic. In each case, we present the necessary and sufficient conditions
for the conversion to be possible for any pair of states, emphasizing a
geometrical representation of the conditions in terms of Lorenz curves. We also
review the problem of quantifying the nonuniformity of a state, in particular
through the use of generalized entropies. Quantum state conversion problems in
this resource theory can be shown to be always reducible to their classical
counterparts, so that there are no inherently quantum-mechanical features
arising in such problems. This body of work also demonstrates that the standard
formulation of the second law of thermodynamics is inadequate as a criterion
for deciding whether or not a given state transition is possible.


title: Passive collections of differential power series algebra

abstract:
  We consider a differential algebra F of formal power series in infinitely
many variables. We define the important notions of a normalized set of
generators for an ideal of F and a regular quotient algebra. The concept of the
passive collection being analog of involutive system of the nonlinear partial
differential equations and Gr\"obner basis is introduced. Using special
partitions of the algebra F and action of a semigroup on F, the sufficient
conditions of passivity are obtained. The proof of the main theorem essentially
differs from similar one for the differential equations and we obtain more
general statement.


title: AdS braneworld with Backreaction

abstract:
  We review the tachyon model derived from the dynamics of a 3-brane moving in
the AdS5 bulk. The bulk geometry is based on the Randall-Sundrum II model
extended to include the radion. The effective tachyon Lagrangian is modified
due to the back-reaction of the brane on the bulk geometry.


title: Mind: An Archaeological Perspective

abstract:
  What can relics of the past tell us about the thoughts and beliefs of the
people who invented and used them? Recent collaborations at the frontier of
archaeology, anthropology, and cognitive science are culminating in speculative
but nevertheless increasingly sophisticated efforts to unravel how modern human
cognition came about. By considering objects within their archaeological
context, we have begun to piece together something of the way of life of people
who inhabited particular locales, which in turn reflects their underlying
thought processes.


title: The Mythical Snake which Swallows its Tail: Einstein's matter world

abstract:
  In 1917 Einstein introduced into his field equations a cosmological term
having the cosmological constant as a coefficient, in order that the theory
should yield a static universe. Einstein desired to eliminate absolute space
from physics according to "Mach's ideas". De Sitter objected to the
"world-matter" in Einstein's world, and proposed a vacuum solution of
Einstein's field equations with the cosmological constant and with no
"world-matter". In 1920 the world-matter of Einstein's world was equivalent to
"Mach's Ether", a carrier of the effects of inertia. De Sitter's 1917 solution
predicted a spectral shift effect. In 1923 Eddington and Weyl adopted De
Sitter's model and studied this effect. Einstein objected to this "cosmological
problem". In 1922-1927, Friedmann and Lamaitre published dynamical universe
models. Friedmann's model with cosmological constant equal to zero was the
simplest general relativity universe. Einstein was willing to accept the
mathematics, but not the physics of a dynamical universe. In 1929 Hubble
announced the discovery that the actual universe is apparently expanding. In
1931 Einstein accepted Friedmann's model with a cosmological constant equal to
zero, which he previously abhorred; he claimed that one did not need the
cosmological term anymore. It was very typical to Einstein that he used to do a
theoretical work and he cared about experiments and observations. This paper is
a new interpretation to Einstein's cosmological considerations over the period
1917-1931.


title: On Canonical Subfield Preserving Polynomials

abstract:
  Explicit monoid structure is provided for the class of canonical subfield
preserving polynomials over finite fields. Some classical results and
asymptotic estimates will follow as corollaries.


title: The prompt-early afterglow connection in GRBs

abstract:
  We study the observed correlations between the duration and luminosity of the
early afterglow plateau and the isotropic gamma-ray energy release during the
prompt phase. We discuss these correlations in the context of two scenarios for
the origin of the plateaus. In the first one the afterglow is made by the
forward shock and the plateau results from variations of the microphysics
parameters while in the second one the early afterglow is made by a long-lived
reverse shock propagating in a low Lorentz factor tail of the ejecta.


title: A Young-Laplace law for black hole horizons

abstract:
  Black hole horizon sections, modelled as marginally outer trapped surfaces
(MOTS), possess a notion of stability admitting a spectral characterization.
Specifically, the "principal eigenvalue" \lambda_o of the MOTS-stability
operator (an elliptic operator on horizon sections) must be non-negative. We
discuss the expression of \lambda_o for axisymmetric stationary black hole
horizons and show that, remarkably, it presents the form of the Young-Laplace
law for soap bubbles in equilibrium, if \lambda_o is identified with a formal
pressure difference between the inner and outer sides of the "bubble". In this
view, that endorses the existing fluid analogies for black hole horizons,
MOTS-stability is interpreted as a consequence of a pressure increase in the
black hole trapped region.


title: Higgs Boson Pair Production at Next-to-Next-to-Leading Order in QCD

abstract:
  We compute the next-to-next-to-leading order QCD corrections for Standard
Model Higgs boson pair production inclusive cross section at hadron colliders
within the large top-mass approximation. We provide numerical results for the
LHC, finding that the corrections are large, resulting in an increase of ${\cal
O}(20%)$ with respect to the next-to-leading order result at c.m. energy
$\sqrt{s_H}=14\,\text{TeV}$. We observe a substantial reduction in the scale
dependence, with overlap between the current and previous order prediction. All
our results are normalized using the full top- and bottom-mass dependence at
leading order. We also provide analytical expressions for the K factors as a
function of $s_H$.


title:
Full t-matrix approach to quasiparticle interference in
  non-centrosymmetric superconductors

abstract:
  We develop the full t-matrix theory of quasiparticle interference (QPI) for
non-centrosymmetric (NCS) superconductors with Rashba spin-orbit coupling. We
give a closed solution for the QPI spectrum for arbitrary combination and
strength of nonmagnetic (Vc) and magnetic (Vm) impurity scattering potentials
in terms of integrated normal and anomalous Green's functions. The theory is
applied to a realistic 2D model of the Ce-based 131- type heavy fermion
superconductors. We discuss the QPI dependence on frequency, composition and
strength of scattering and compare with Born approximation results. We show
that the QPI pattern is remarkably stable against changes in the scattering
model and can therefore give reliable information on the properties of
Rashba-split Fermi surface sheets and in particular on the accidental nodal
position of the mixed singlet-triplet gap function in NCS superconductors.


title:
Asymptotic Properties of Drift Parameter Estimator Based on Discrete
  Observations of Stochastic Differential Equation Driven by Fractional
  Brownian Motion

abstract:
  We consider a problem of statistical estimation of an unknown drift parameter
for a stochastic differential equation driven by fractional Brownian motion.
Two estimators based on discrete observations of solution to the stochastic
differential equations are constructed. It is proved that the estimators
converge almost surely to the parameter value as the observation interval
expands and the distance between observations vanishes. A bound for the rate of
convergence is given and numerical simulations are presented. As an auxilliary
result of independent interest we establish global estimates for fractional
derivative of fractional Brownian motion.


title:
The vector resonance triplet with the direct coupling to the third quark
  generation

abstract:
  The effective Lagrangian with scalar and vector resonances that might result
from new strong physics beyond the SM is formulated and studied. In particular,
the scalar resonance representing the recently discovered 125-GeV boson is
complemented with the SU(2)_{L+R} triplet of hypothetical vector resonances.
Motivated by experimental and theoretical considerations, the vector resonance
is allowed to couple directly to the third quark generation only. The coupling
is chiral-dependent and the interaction of the right top quark can differ from
that of the right bottom quark. To estimate the applicability range of the
effective Lagrangian the unitarity of the gauge boson scattering amplitudes is
analyzed. The experimental fits and limits on the free parameters of the vector
resonance triplet are investigated.


title: Combinatorics of cycle lengths on Wehler K3 Surfaces over finite fields

abstract:
  We study the dynamics of maps arising from the composition of two
non-commuting involution on a K3 surface. These maps are a particular example
of reversible maps, i.e., maps with a time reversing symmetry. The
combinatorics of the cycle distribution of two non-commuting involutions on a
finite phase space was studied by Roberts and Vivaldi. We show that the
dynamical systems of these K3 surfaces satisfy the hypotheses of their results,
providing a description of the cycle distribution of the rational points over
finite fields. Furthermore, we extend the involutions to include the case where
there are degenerate fibers and prove a description of the cycle distribution
in this more general situation.


title: New Light on Dark Photons

abstract:
  "Dark Photons", light new vector particles V kinetically mixed with the
photon, are a frequently considered extension of the Standard Model. For masses
below 10 keV they are emitted from the solar interior. In the limit of small
mass m_V the dark photon flux is strongly peaked at low energies and we
demonstrate that the constraint on the atomic ionization rate imposed by the
results of the XENON10 Dark Matter experiment sets the to-date most stringent
limit on the kinetic mixing parameter of this model: \kappa*m_V < 3*10^{-12}
eV. The result significantly improves previous experimental bounds and
surpasses even the most stringent astrophysical and cosmological limits in a
seven-decade-wide interval of m_V.


title: Unambiguous determination of spin dephasing times in ZnO

abstract:
  Time-resolved magneto-optics is a well-established optical pump probe
technique to generate and to probe spin coherence in semiconductors. By this
method, spin dephasing times T_2^* can easily be determined if their values are
comparable to the available pump-probe-delays. If T_2^* exceeds the laser
repetition time, however, resonant spin amplification (RSA) can equally be used
to extract T_2^*. We demonstrate that in ZnO these techniques have several
tripping hazards resulting in deceptive values for T_2^* and show how to avoid
them. We show that the temperature dependence of the amplitude ratio of two
separate spin species can easily be misinterpreted as a strongly temperature
dependent T_2^* of a single spin ensemble, while the two spin species have
T_2^* values which are nearly independent of temperature. Additionally,
consecutive pump pulses can significantly diminish the spin polarization, which
remains from previous pump pulses. While this barely affects T_2^* values
extracted from delay line scans, it results in seemingly shorter T_2^* values
in RSA.


title:
Weighted inequalities related to a Muckenhoupt and Wheeden problem for
  one-side singular integrals

abstract:
  In this paper we obtain for $T^+$, a one-sided singular integral given by a
Calder\'on-Zygmund kernel with support in $(-\infty,0)$, a $L^p(w)$ bound when
$w\in A_1^+$. A. K. Lerner, S. Ombrosi, and C. P\'erez proved in [ "$A_{1}$
Bounds for Calder\'on-Zygmund operators related to a problem of Muckenhoupt and
Wheeden", Math. Res. Lett. \textbf{16} (2009), no. 1, 149-156] that this bound
is sharp with respect to $||w||_{A_1} $ and $p$ . We also give a
$L^{1,\infty}(w)$ estimate, for a related problem of Muckenhoupt and Wheeden
for $w\in A_1^+$ . We improve the classical results, for one-sided singular
integrals, by putting in the inequalities a wider class of weights.


title: Adaptive estimation of convex and polytopal support

abstract:
  We estimate the support of a uniform density, when it is assumed to be a
convex polytope or, more generally, a convex body in $\R^d$. In the polytopal
case, we construct an estimator achieving a rate which does not depend on the
dimension $d$, unlike the other estimators that have been proposed so far. For
$d\geq 3$, our estimator has a better risk than the previous ones, and it is
nearly minimax, up to a logarithmic factor. We also propose an estimator which
is adaptive with respect to the structure of the boundary of the unknown
support.


title: The Random Bit Complexity of Mobile Robots Scattering

abstract:
  We consider the problem of scattering $n$ robots in a two dimensional
continuous space. As this problem is impossible to solve in a deterministic
manner, all solutions must be probabilistic. We investigate the amount of
randomness (that is, the number of random bits used by the robots) that is
required to achieve scattering. We first prove that $n \log n$ random bits are
necessary to scatter $n$ robots in any setting. Also, we give a sufficient
condition for a scattering algorithm to be random bit optimal. As it turns out
that previous solutions for scattering satisfy our condition, they are hence
proved random bit optimal for the scattering problem. Then, we investigate the
time complexity of scattering when strong multiplicity detection is not
available. We prove that such algorithms cannot converge in constant time in
the general case and in $o(\log \log n)$ rounds for random bits optimal
scattering algorithms. However, we present a family of scattering algorithms
that converge as fast as needed without using multiplicity detection. Also, we
put forward a specific protocol of this family that is random bit optimal ($n
\log n$ random bits are used) and time optimal ($\log \log n$ rounds are used).
This improves the time complexity of previous results in the same setting by a
$\log n$ factor. Aside from characterizing the random bit complexity of mobile
robot scattering, our study also closes its time complexity gap with and
without strong multiplicity detection (that is, $O(1)$ time complexity is only
achievable when strong multiplicity detection is available, and it is possible
to approach it as needed otherwise).


title: Skorohod and Stratonovich integration in the plane

abstract:
  This article gives an account on various aspects of stochastic calculus in
the plane. Specifically, our aim is 3-fold: (i) Derive a pathwise change of
variable formula for a path indexed by a square, satisfying some H\"older
regularity conditions with a H\"older exponent greater than 1/3. (ii) Get some
Skorohod change of variable formulas for a large class of Gaussian processes
defined on the suqare. (iii) Compare the bidimensional integrals obtained with
those two methods, computing explicit correction terms whenever possible. As a
byproduct, we also give explicit forms of corrections in the respective change
of variable formulas.


title:
Symmetries, Cluster Synchronization, and Isolated Desynchronization in
  Complex Networks

abstract:
  Synchronization is of central importance in power distribution,
telecommunication, neuronal, and biological networks. Many networks are
observed to produce patterns of synchronized clusters, but it has been
difficult to predict these clusters or understand the conditions under which
they form, except for in the simplest of networks. In this article, we shed
light on the intimate connection between network symmetry and cluster
synchronization. We introduce general techniques that use network symmetries to
reveal the patterns of synchronized clusters and determine the conditions under
which they persist. The connection between symmetry and cluster synchronization
is experimentally explored using an electro-optic network. We experimentally
observe and theoretically predict a surprising phenomenon in which some
clusters lose synchrony while leaving others synchronized. The results could
guide the design of new power grid systems or lead to new understanding of the
dynamical behavior of networks ranging from neural to social.


title:
Conservation laws for surfaces of constant mean curvature in
  3-dimensional space forms

abstract:
  The exterior differential system for constant mean curvature (CMC) surfaces
in a 3-dimensional space form is an elliptic Monge-Ampere system defined on the
unit tangent bundle. We determine the infinite sequence of higher-order
symmetries and conservation laws via an enhanced prolongation modelled on a
loop algebra valued formal Killing field. As a consequence we establish
Noether's theorem for the CMC system and there is a canonical isomorphism
between the symmetries and conservation laws.
  A geometric interpretation of the $\mathbb{S}^{1}$-family of associate
surfaces leads to an integrable extension for a non-local symmetry called
spectral symmetry. We show that the corresponding spectral conservation law
exists as a secondary characteristic cohomology class.
  For a compact linear finite type CMC surface of arbitrary genus, we observe
that the monodromies of the associated flat
$\mathfrak{sl}(2,\mathbb{C})$-connection commute with each other. It follows
that a single spectral curve is defined as the completion of the set of
eigenvalues of the entire monodromies. This agrees with the recent result that
a compact high genus linear finite type CMC surface necessarily factors through
a branched covering of a torus.
  We introduce a sequence of Abel-Jacobi maps defined by the periods of
conservation laws. For the class of deformations of CMC surfaces which scale
the Hopf differential by a real parameter, we compute the first order truncated
Picard-Fuchs equation. The resulting formulae for the first few terms exhibit a
similarity with the Griffiths transversality theorem for variation of Hodge
structures.


title: Kink-Antikink Scattering in \phi^4 and \phi^6 Models

abstract:
  For kink-antikink scattering within the \phi^4 non--linear field theory in
one space and one time dimension resonance type configurations emerge when the
relative velocity between kink and antikink falls below a critical value. It
has been conjectured that the vibrational excitation of the kink would be the
source for these resonances because (simplified) collective coordinate
calculations, that emphasized on this excitation, qualitatively reproduced
those resonances. Surprisingly a numerical study in the \phi^6 field theory
also exhibited such resonances even though it does not contain the vibrational
excitation. To explore this contradiction we start from the working hypothesis
that in either model any collective coordinate ansatz which includes a degree
of freedom similar to the vibrational excitation leads to resonances,
regardless of whether or not this mode emerges as a solution to the
(linearized) field equations. To this end we compare numerical results in the
\phi^4 and \phi^6 models that arise from the full set of partial differential
equations to those from the ordinary differential equations for a collective
coordinate ansatz. An inaccuracy in literature formulas for the collective
coordinate approach in the \phi^4 model requires to revisit those calculations.


title: Assessment of OpenStreetMap Data - A Review

abstract:
  The meaning and purposes of web has been changing and evolving day by day.
Web 2. 0 encouraged more contribution by the end users. This movement provided
revolutionary methods of sharing and computing data by crowdsourcing such as
OpenStreetmap, also called "the wikification of maps" by some researchers. When
crowdsourcing collects huge data with help of general public with varying level
of mapping experience, the focus of researcher should be on analysing the data
rather than collecting it. Researchers have assessed the quality of
OpenStreetMap data by comparing it with proprietary data or data of
governmental map agencies. This study reviews the research work for assessment
of Open- StreetMap Data and also discusses about the future directions.


title: An Expectation-Maximization Algorithm for the Matrix Normal Distribution

abstract:
  Dramatic increases in the size and dimensionality of many recent data sets
make crucial the need for sophisticated methods that can exploit inherent
structure and handle missing values. In this article we derive an
expectation-maximization (EM) algorithm for the matrix normal distribution, a
distribution well-suited for naturally structured data such as spatio-temporal
data. We review previously established maximum likelihood matrix normal
estimates, and then consider the situation involving missing data. We apply our
EM method in a simulation study exploring errors across different dimensions
and proportions of missing data. We compare these errors and computational
running times to those from two alternative methods. Finally, we implement the
proposed EM method on a satellite image dataset to investigate land-cover
classification separability.


title: Adversarial Multiple Access Channels with Individual Injection Rates

abstract:
  We study deterministic distributed broadcasting in synchronous
multiple-access channels. Packets are injected into $n$ nodes by a window-type
adversary that is constrained by a window $w$ and injection rates individually
assigned to all nodes. We investigate what queue size and packet latency can be
achieved with the maximum aggregate injection rate of one packet per round,
depending on properties of channels and algorithms. We give a non-adaptive
algorithm for channels with collision detection and an adaptive algorithm for
channels without collision detection that achieve $O(\min(n+w,w\log n))$ packet
latency. We show that packet latency has to be either $\Omega(w \max (1,\log_w
n))$, when $w\le n$, or $\Omega(w+n)$, when $w>n$, as a matching lower bound to
these algorithms. We develop a non-adaptive algorithm for channels without
collision detection that achieves $O(n+w)$ queue size and $O(nw)$ packet
latency. This is in contrast with the adversarial model of global injection
rates, in which non-adaptive algorithms with bounded packet latency do not
exist (Chlebus et al. Distributed Computing 22(2): 93 - 116, 2009). Our
algorithm avoids collisions produced by simultaneous transmissions; we show
that any algorithm with this property must have $\Omega(nw)$ packet latency.


title: Simple groups stabilizing polynomials

abstract:
  We study the problem of determining, for a polynomial function $f$ on a
vector space $V$, the linear transformations $g$ of $V$ such that $f g = f$. In
case $f$ is invariant under a simple algebraic group $G$ acting irreducibly on
$V$, we note that the subgroup of $GL(V)$ stabilizing $f$ often has identity
component $G$ and we give applications realizing various groups, including the
largest exceptional group $E_8$, as automorphism groups of polynomials and
algebras. We show that starting with a simple group $G$ and an irreducible
representation $V$, one can almost always find an $f$ whose stabilizer has
identity component $G$ and that no such $f$ exists in the short list of
excluded cases. This relies on our core technical result, the enumeration of
inclusions $G < H \le SL(V)$ such that $V/H$ has the same dimension as $V/G$.
The main results of this paper are new even in the special case where $k$ is
the complex numbers.


title: On the new late B- and early A-type periodic variable stars

abstract:
  We summarize the properties of the new periodic, small amplitude, variable
stars recently discovered in the open cluster NGC 3766. They are located in the
region of the Hertzsprung-Russell diagram between \delta\ Sct and slowly
pulsating B stars, a region where no sustained pulsation is predicted by
standard models. The origin of their periodic variability is currently unknown.
We also discuss how the Gaia mission, to be launched at the end of 2013, can
contribute to our knowledge of those stars.


title:
Continuous-time Proportional-Integral Distributed Optimization for
  Networked Systems

abstract:
  In this paper we explore the relationship between dual decomposition and the
consensus-based method for distributed optimization. The relationship is
developed by examining the similarities between the two approaches and their
relationship to gradient-based constrained optimization. By formulating each
algorithm in continuous-time, it is seen that both approaches use a gradient
method for optimization with one using a proportional control term and the
other using an integral control term to drive the system to the constraint set.
Therefore, a significant contribution of this paper is to combine these methods
to develop a continuous-time proportional-integral distributed optimization
method. Furthermore, we establish convergence using Lyapunov stability
techniques and utilizing properties from the network structure of the
multi-agent system.


title:
Constraints on Blazar Jet Conditions During Gamma-Ray Flaring from
  Radiative Transfer Modeling

abstract:
  As part of a program to investigate jet flow conditions during GeV gamma-ray
flares detected by Fermi, we are using UMRAO multi-frequency, centimeter-band
total flux density and linear polarization monitoring observations to constrain
radiative transfer models incorporating propagating shocks orientated at an
arbitrary angle to the flow direction. We describe the characteristics of the
model, illustrate how the data are used to constrain the models, and present
results for three program sources with diverse characteristics: PKS 0420-01, OJ
287, and 1156+295. The modeling of the observed spectral behavior yields
information on the sense, strength and orientation of the shocks producing the
radio-band flaring; on the energy distribution of the radiating particles; and
on the observer's viewing angle with respect to the jet independent of VLBI
data. We present evidence that, while a random component dominates the jet
magnetic field, a distinguishing feature of those radio events with an
associated gamma-ray flare is the presence of a weak but non-negligible ordered
magnetic field component along the jet axis.


title:
Coordinate (in)dependence and quantum inteference in quantum spin
  tunnelling

abstract:
  We show how to calculate the amplitude for quantum spin tunneling with a $z$
easy axis. In this case, using the usual spherical polar angles to parametrize
spin coherent states, typically the tunnelling variable is the polar angle
$\theta$, passing from 0 to $\pi$, while the azimuthal angle $\phi$ is
imaginary and constant. As the energy is constant along the tunnelling
trajectory and normalized to vanish, and the Wess-Zumino term $S_{WZ} = is\int
d\tau \thinspace\dot{\phi}(1-\cos\theta )$ also seems to vanish, it is
difficult to see how we can obtain a non-zero contribution to the tunnelling
amplitude. Indeed, the instanton trajectory gives zero contribution. We show
how, the entire contribution to the tunnelling amplitude in fact comes from
moving $\phi$ from zero to its complex value at the beginning of the tunnelling
trajectory at $\theta=0$ and moving it back to zero at the end at $\theta=\pi$.
The Wess-Zumino term can also be expressed in a coordinate system independent
manner as $S_{WZ} =is\int d\tau d\xi \left[\hat n\cdot (\partial_\tau\hat
n\times\partial_\xi\hat n)\right]$, a format that does not appear to be well
known or understood in the condensed matter literature. We show in detail how
this expression corresponds exactly to the more familiar, coordinate system
dependent expression, and how to obtain the tunnelling amplitude directly from
it.


title: Silicon-based Infrared Metamaterials with Ultra-Sharp Fano Resonances

abstract:
  Metamaterials and meta-surfaces represent a remarkably versatile platform for
light manipulation, biological and chemical sensing, nonlinear optics, and even
spaser lasing. Many of these applications rely on the resonant nature of
metamaterials, which is the basis for extreme spectrally selective
concentration of optical energy in the near field. The simplicity of free-space
light coupling into sharply-resonant meta-surfaces with high resonance quality
factors Q>>1 is a significant practical advantage over the extremely
angle-sensitive diffractive structures or inherently inhomogeneous high-Q
photonic structures such as toroid or photonic crystal microcavities. Such
spectral selectivity is presently impossible for the overwhelming majority of
metamaterials that are made of metals and suffer from high plasmonic losses.
Here, we propose and demonstrate Fano-resonant all-semiconductor optical
meta-surfaces supporting optical resonances with quality factors Q>100 that are
almost an order of magnitude sharper than those supported by their plasmonic
counterparts. These silicon-based structures are shown to be planar chiral,
opening exciting possibilities for efficient ultra-thin circular polarizers and
narrow-band thermal emitters of circularly polarized radiation.


title:
Conceptual Closure: How Memories are Woven into an Interconnected
  Worldview

abstract:
  This paper describes a tentative model for how discrete memories transform
into an interconnected conceptual network, or worldview, wherein relationships
between memories are forged by way of abstractions. The model draws on
Kauffman's theory of how an information-evolving system could emerge through
the formation and closure of an autocatalytic network. Here, the information
units are not catalytic molecules, but memories and abstractions, and the
process that connects them is not catalysis but reminding events (i.e. one
memory evokes another). The result is a worldview that both structures, and is
structured by, self-triggered streams of thought.


title:
Human mobility and time spent at destination: Impact on spatial epidemic
  spreading

abstract:
  Host mobility plays a fundamental role in the spatial spread of infectious
diseases. Previous theoretical works based on the integration of network theory
into the metapopulation framework have shown that the heterogeneities that
characterize real mobility networks favor the propagation of epidemics.
Nevertheless, the studies conducted so far assumed the mobility process to be
either Markovian or non-Markovian with a fixed traveling time scale. Available
statistics however show that the time spent by travelers at destination is
characterized by wide fluctuations, ranging between a single day up to several
months. Such varying length of stay crucially affects the chance and duration
of mixing events among hosts and may therefore have a strong impact on the
spread of an emerging disease. Here, we present an analytical and computational
study of epidemic processes on a complex subpopulation network where travelers
have memory of their origin and spend a heterogeneously distributed time
interval at their destination. Through analytical calculations and numerical
simulations we show that the heterogeneity of the length of stay alters the
expression of the threshold between local outbreak and global invasion, and,
moreover, it changes the epidemic behavior of the system in case of a global
outbreak. Additionally, our theoretical framework allows us to study the effect
of changes in the traveling behavior in response to the infection, by
considering a scenario in which sick individuals do not leave their home
location. Finally, we compare the results of our non-Markovian framework with
those obtained with a classic Markovian approach and find relevant differences
between the two, in the estimate of the epidemic invasion potential, as well as
of the timing and the pattern of its spatial spread.


title: Constraining Higgs Properties in Associated Production

abstract:
  The Higgs boson H produced in association with a vector boson V=W, Z is the
main production mechanism for searches at the Tevatron and forms an important
part of Higgs analyses at the LHC. We show here that the V+H invariant mass
distribution and the energy dependence of associated production provide
powerful ways of constraining Higgs properties, such as its spin-parity and
dimension-6 operator coefficients.


title: Quantum limits on post-selected, probabilistic quantum metrology

abstract:
  Probabilistic metrology attempts to improve parameter estimation by
occasionally reporting an excellent estimate and the rest of the time either
guessing or doing nothing at all. Here we show that probabilistic metrology can
never improve quantum limits on estimation of a single parameter, both on
average and asymptotically in number of trials, if performance is judged
relative to mean-square estimation error. We extend the result by showing that
for a finite number of trials, the probability of obtaining better estimates
using probabilistic metrology, as measured by mean-square error, decreases
exponentially with the number of trials. To be tight, the performance bounds we
derive require that likelihood functions be approximately normal, which in turn
depends on how rapidly specific distributions converge to a normal distribution
with number of trials.


title:
Randomized Wavelets on Arbitrary Domains and Applications to Functional
  MRI Analysis

abstract:
  Wavelets have been shown to be effective bases for many classes of natural
signals and images. Standard wavelet bases have the entire vector space
$\mathbb R^n$ as their natural domain. It is fairly straightforward to adapt
these to rectangular subdomains, and there also exist constructions for domains
with more complex boundaries. However those methods are ineffective when we
deal with domains that are very arbitrary and convoluted. A particular example
of interest is the human cortex, which is the part of the human brain where all
the cognitive activity takes place. In this thesis, we use the lifting scheme
to design wavelets on arbitrary volumes, and in particular on volumes having
the structure of the human cortex. These wavelets have an element of randomness
in their construction, which allows us to repeat the analysis with many
different realizations of the wavelet bases and averaging the results, a method
that improves the power of the analysis. Next, we apply this type of wavelet
transforms to the statistical analysis to fMRI data, and we show that it
enables us to achieve greater spatial localization than other, more standard
techniques.


title:
Gravitational Collapse of a Homogeneous Scalar Field in Deformed Phase
  Space

abstract:
  We study the gravitational collapse of a homogeneous scalar field, minimally
coupled to gravity, in the presence of a particular type of dynamical
deformation between the canonical momenta of the scale factor and of the scalar
field. In the absence of such a deformation, a class of solutions can be found
in the literature [R. Goswami and P. S. Joshi, arXiv:gr-qc/0410144],
%\cite{JG04}, whereby a curvature singularity occurs at the collapse end state,
which can be either hidden behind a horizon or be visible to external
observers. However, when the phase-space is deformed, as implemented herein
this paper, we find that the singularity may be either removed or instead,
attained faster. More precisely, for negative values of the deformation
parameter, we identify the emergence of a negative pressure term, which slows
down the collapse so that the singularity is replaced with a bounce. In this
respect, the formation of a dynamical horizon can be avoided depending on the
suitable choice of the boundary surface of the star. Whereas for positive
values, the pressure that originates from the deformation effects assists the
collapse toward the singularity formation. In this case, since the collapse
speed is unbounded, the condition on the horizon formation is always satisfied
and furthermore the dynamical horizon develops earlier than when the
phase-space deformations are absent. These results are obtained by means of a
thoroughly numerical discussion.


title: Controlling sign problems in spin models using tensor renormalization

abstract:
  We consider the sign problem for classical spin models at complex $\beta
=1/g_0^2$ on $L\times L$ lattices. We show that the tensor renormalization
group method allows reliable calculations for larger Im$\beta$ than the
reweighting Monte Carlo method. For the Ising model with complex $\beta$ we
compare our results with the exact Onsager-Kaufman solution at finite volume.
The Fisher zeros can be determined precisely with the TRG method. We check the
convergence of the TRG method for the O(2) model on $L\times L$ lattices when
the number of states $D_s$ increases. We show that the finite size scaling of
the calculated Fisher zeros agrees very well with the Kosterlitz-Thouless
transition assumption and predict the locations for larger volume. The location
of these zeros agree with Monte Carlo reweighting calculation for small volume.
The application of the method for the O(2) model with a chemical potential is
briefly discussed.

categories: hep-lat cond-mat.stat-mech cond-mat.str-el hep-th


title:
Reconstructing primordial power spectrum using Planck and SDSS-III
  measurements

abstract:
  We develop an accurate and efficient Bayesian method to reconstruct the
primordial power spectrum in a model-independent way, and apply it to the
latest cosmic microwave background measurement from Planck mission, and the
large scale structure observation of SDSS-III BOSS (CMASS) sample, combined
with the type Ia supernovae sample (SNLS 3-year) and the measurements of baryon
acoustic oscillations from SDSS-II, 6dF, and WiggleZ survey. We confirm that
the scale-invariant primordial power spectrum is strongly disfavored, and a
model with suppressed power on horizon scales is supported by current data. We
also find that a modulation on scales $5\times10^{-4}~\textrm{Mpc}^{-1}
\lesssim k \lesssim 0.01~\textrm{Mpc}^{-1}$ is mildly preferred at $2\sigma$
confidence level, whose origin needs further investigation.


title:
A priori bound on the velocity in axially symmetric Navier-Stokes
  equations

abstract:
  Let $v$ be the velocity of Leray-Hopf solutions to the axially symmetric
three-dimensional Navier-Stokes equations. Under suitable conditions for
initial values, we prove the following a priori bound \[ |v(x, t)| \le
\frac{C}{r^2} |\ln r|^{1/2}, \]where $r \in (0, 1/2)$ is the distance from $x$
to the z axis, and $C$ is a constant depending only on the initial value.
  This provides a pointwise upper bound (worst case scenario) for possible
singularities while the recent papers \cite{CSTY2} and \cite{KNSS} gave a lower
bound. The gap is polynomial order 1 modulo a half log term.


title: Dust Reddened Quasars in FIRST and UKIDSS: Beyond the Tip of the Iceberg

abstract:
  We present the results of a pilot survey to find dust-reddened quasars by
matching the FIRST radio catalog to the UKIDSS near-infrared survey, and using
optical data from SDSS to select objects with very red colors. The deep K-band
limit provided by UKIDSS allows for finding more heavily-reddened quasars at
higher redshifts as compared with previous work using FIRST and 2MASS. We
selected 87 candidates with K<=17.0 from the UKIDSS Large Area Survey (LAS)
First Data Release (DR1) which covers 190 deg2. These candidates reach up to
~1.5 magnitudes below the 2MASS limit and obey the color criteria developed to
identify dust-reddened quasars. We have obtained 61 spectroscopic observations
in the optical and/or near-infrared as well as classifications in the
literature and have identified 14 reddened quasars with E(B-V)>0.1, including
three at z>2. We study the infrared properties of the sample using photometry
from the WISE Observatory and find that infrared colors improve the efficiency
of red quasar selection, removing many contaminants in an infrared-to-optical
color-selected sample alone. The highest-redshift quasars (z > 2) are only
moderately reddened, with E(B-V) ~ 0.2-0.3. We find that the surface density of
red quasars rises sharply with faintness, comprising up to 17% of blue quasars
at the same apparent K-band flux limit. We estimate that to reach more heavily
reddened quasars (i.e., E(B-V) > 0.5) at z>2 and a depth of K=17 we would need
to survey at least ~2.5 times more area.


title:
A Unified Filter for Simultaneous Input and State Estimation of Linear
  Discrete-time Stochastic Systems

abstract:
  In this paper, we present a unified optimal and exponentially stable filter
for linear discrete-time stochastic systems that simultaneously estimates the
states and unknown inputs in an unbiased minimum-variance sense, without making
any assumptions on the direct feedthrough matrix. We also derive input and
state observability/detectability conditions, and analyze their connection to
the convergence and stability of the estimator. We discuss two variations of
the filter and their optimality and stability properties, and show that filters
in the literature, including the Kalman filter, are special cases of the filter
derived in this paper. Finally, illustrative examples are given to demonstrate
the performance of the unified unbiased minimum-variance filter.


title: Quantitative Homotopy Theory in Topological Data Analysis

abstract:
  This paper lays the foundations of an approach to applying Gromov's ideas on
quantitative topology to topological data analysis. We introduce the
"contiguity complex", a simplicial complex of maps between simplicial complexes
defined in terms of the combinatorial notion of contiguity. We generalize the
Simplicial Approximation Theorem to show that the contiguity complex
approximates the homotopy type of the mapping space as we subdivide the domain.
We describe algorithms for approximating the rate of growth of the components
of the contiguity complex under subdivision of the domain; this procedure
allows us to computationally distinguish spaces with isomorphic homology but
different homotopy types.


title: Stability of the Centrality of Unions of Networks on the Same Vertex Set

abstract:
  Let $G^1(V,E_1)$ and $G^2(V,E_2)$ be two networks on the same vertex set $V$
and consider the union of edges $G(V, E_1 \cup E_2)$. This paper studies the
stability of the Degree, Betweenness and Eigenvector Centrality of the
resultant network, $G(V, E_1 \cup E_2)$. Specifically assume $v^1_{max}$ and
$v^c_{max}$ are the highest centrality vertices of $G^1(V,E_1)$ and $G(V, E_1
\cup E_2)$ respectively, we want to find $Pr(v^1_{max} = v^c_{max})$.


title: Twists of Pl\"ucker coordinates as dimer partition functions

abstract:
  The homogeneous coordinate ring of the Grassmannian Gr(k,n) has a cluster
structure defined in terms of planar diagrams known as Postnikov diagrams. The
cluster corresponding to such a diagram consists entirely of Pluecker
coordinates. We introduce a twist map on Gr(k,n), related to the
Berenstein-Fomin-Zelevinsky-twist, and give an explicit Laurent expansion for
the twist of an arbitrary Pluecker coordinate in terms of the cluster variables
associated with a fixed Postnikov diagram. The expansion arises as a (scaled)
dimer partition function of a weighted version of the bipartite graph dual to
the Postnikov diagram, modified by a boundary condition determined by the
Pluecker coordinate. We also relate the twist map to a maximal green sequence.

categories: math.CO cond-mat.stat-mech hep-th math.RT


title: Pulling Out All the Stops: Searching for RPV SUSY with Stop-Jets

abstract:
  If the lighter stop eigenstate decays directly to two jets via baryonic
R-parity violation, it could have escaped existing LHC and Tevatron searches in
four-jet events, even for masses as small as 100 GeV. In order to recover
sensitivity in the face of increasingly harsh trigger requirements at the LHC,
we propose a search for stop pairs in the highly-boosted regime, using the
approaches of jet substructure. We demonstrate that the four-jet triggers can
be completely bypassed by using inclusive jet-H_T triggers, and that the
resulting QCD continuum background can be processed by substructure methods
into a featureless spectrum suitable for a data-driven bump-hunt down to 100
GeV. We estimate that the LHC 8 TeV run is sensitive to 100 GeV stops with
decays of any flavor at better than 5-sigma level, and could place exclusions
up to 300 GeV or higher. Assuming Minimal Flavor Violation and running a
b-tagged analysis, exclusion reach may extend up to nearly 400 GeV.
Longer-term, the 14 TeV LHC at 300/fb could extend these mass limits by a
factor of two, while continuing to improve sensitivity in the 100 GeV region.


title:
Towards Completing the Standard Model: Vacuum Stability, EWSB and Dark
  Matter

abstract:
  We study the standard model (SM) in its full perturbative validity range
between $\Lambda_QCD$ and the $U(1)_Y$ Landau pole, assuming that a yet unknown
gravitational theory in the UV does not introduce additional particle
thresholds, as suggested by the tiny cosmological constant and the absence of
new stabilising physics at the EW scale. We find that, due to dimensional
transmutation, the SM Higgs potential has a global minimum at 10^26 GeV,
invalidating the SM as a phenomenologically acceptable model in this energy
range. We show that extending the classically scale invariant SM with one
complex singlet scalar S allows us to: (i) stabilise the SM Higgs potential;
(ii) induce a scale in the singlet sector via dimensional transmutation that
generates the negative SM Higgs mass term via the Higgs portal; (iii) provide a
stable CP-odd singlet as the thermal relic dark matter due to CP-conservation
of the scalar potential; (iv) provide a degree of freedom that can act as an
inflaton in the form of the CP-even singlet. The logarithmic behaviour of
dimensional transmutation allows one to accommodate the large hierarchy between
the electroweak scale and the Landau pole, while understanding the latter
requires a new non-perturbative view on the SM.


title: Supersymmetric Exotic Decays of the 125 GeV Higgs Boson

abstract:
  We reveal a set of novel decay topologies for the 125 GeV Higgs boson in
supersymmetry which are initiated by its decay into a pair of neutralinos, and
discuss their collider search strategies. This category of exotic Higgs decays
are characterized by the collider signature: visible objects + $\mbox{${\not\!
E}_{\rm T}$}$, with $\mbox{${\not\! E}_{\rm T}$}$ dominantly arising from
escaping dark matter particles. Their benchmark arises naturally in the
Peccei-Quinn symmetry limit of the MSSM singlet-extensions, which is typified
by the co-existence of three light particles: singlet-like scalar $h_1$ and
pseudoscalar $a_1$, and singlino-like neutralino $\chi_1$, all with masses of
$\lesssim 10$ GeV, and the generically suppression of the exotic decays of the
125 GeV Higgs boson $h_2\to h_1 h_1$, $a_1a_1$ and $\chi_1\chi_1$, however. As
an illustration, we study the decay topology: $h_2 \to \chi_1 \chi_2$, where
the bino-like $\chi_2$ decays to $h_1 \chi_1$ or $a_1 \chi_1$, and $h_1/a_1 \to
f\bar f$, with $f\bar f = \mu^+\mu^-$, $b\bar b$. In the di-muon case
($m_{h_1/a_1} \sim 1$ GeV), a statistical sensitivity of $\frac{S}{\sqrt{B}} >
6 \sigma$ can be achieved easily at the 8 TeV LHC, assuming $\frac{\sigma(pp
\rightarrow W h_2)}{\sigma(pp \rightarrow W h_{\rm SM})} {\rm Br}(h_2 \to
\mu^+\mu^- \chi_1 \chi_1)=0.1$. In the $b\bar b$ case ($m_{h_1/a_1} \sim 45$
GeV), 600 fb$^{-1}$ data at the 14 TeV LHC can lead to a statistical
sensitivity of $\frac{S}{\sqrt{B}} > 5 \sigma$, assuming $\frac{\sigma(pp
\rightarrow Z h_2)}{\sigma(pp \rightarrow Z h_{\rm SM})} {\rm Br}(h_2 \to b\bar
b \chi_1 \chi_1)=0.5$. These exotic decays open a new avenue for exploring new
physics couplings with the 125 GeV Higgs boson at colliders.


title: The galaxy-wide IMF of dwarf late-type to massive early-type galaxies

abstract:
  Observational studies are showing that the galaxy-wide stellar initial mass
function are top-heavy in galaxies with high star-formation rates (SFRs).
Calculating the integrated galactic stellar initial mass function (IGIMF) as a
function of the SFR of a galaxy, it follows that galaxies which have or which
formed with SFRs > 10 Msol yr^-1 would have a top-heavy IGIMF in excellent
consistency with the observations. Consequently and in agreement with
observations, elliptical galaxies would have higher M/L ratios as a result of
the overabundance of stellar remnants compared to a stellar population that
formed with an invariant canonical stellar initial mass function (IMF). For the
Milky Way, the IGIMF yields very good agreement with the disk- and the
bulge-IMF determinations. Our conclusions are that purely stochastic
descriptions of star formation on the scales of a pc and above are falsified.
Instead, star formation follows the laws, stated here as axioms, which define
the IGIMF theory. We also find evidence that the power-law index beta of the
embedded cluster mass function decreases with increasing SFR. We propose
further tests of the IGIMF theory through counting massive stars in dwarf
galaxies.


title: The Neutron Star Mass Distribution

abstract:
  In recent years, the number of pulsars with secure mass measurements has
increased to a level that allows us to probe the underlying neutron star (NS)
mass distribution in detail. We critically review the radio pulsar mass
measurements. For the first time, we are able to analyze a sizable population
of NSs with a flexible modeling approach that can effectively accommodate a
skewed underlying distribution and asymmetric measurement errors. We find that
NSs that have evolved through different evolutionary paths reflect distinctive
signatures through dissimilar distribution peak and mass cutoff values. NSs in
double neutron star and neutron star-white dwarf systems show consistent
respective peaks at 1.33 Msun and 1.55 Msun suggesting significant mass
accretion (delta m~0.22 Msun) has occurred during the spin-up phase. The width
of the mass distribution implied by double NS systems is indicative of a tight
initial mass function while the inferred mass range is significantly wider for
NSs that have gone through recycling. We find a mass cutoff at ~2.1 Msun for
NSs with white dwarf companions which establishes a firm lower bound for the
maximum NS mass. This rules out the majority of strange quark and soft equation
of state models as viable configurations for NS matter. The lack of truncation
close to the maximum mass cutoff along with the skewed nature of the inferred
mass distribution both enforce the suggestion that the 2.1 Msun limit is set by
evolutionary constraints rather than nuclear physics or general relativity, and
the existence of rare super-massive NSs is possible.


title: Extreme Galaxies During Reionization: Testing ISM and Disk Models

abstract:
  We test the ability of equilibrium galactic disk and one-zone interstellar
medium models to describe the physical and emission properties of quasar hosts,
submillimeter galaxies, and Lyman-alpha emitters at z>~6. The size, line
widths, star formation rates, black hole accretion rates, gas masses and
temperatures, and the relationships between these properties are all
well-described by our model, and we provide approximate fitting formulae for
comparison with future observations. However, comparing our carbon line
predictions to observations reveals differences between the ISM at low and high
redshifts. Our underestimate of the [CII] line emission indicates either higher
star formation efficiencies in high-redshift molecular clouds or less depletion
of metals into dust at fixed metallicity. Further, our over-prediction of the
CO(6-5)/CO(1-0) ratio suggests that molecular clouds in real high-redshift
galaxies have a lower turbulent Mach number and more subthermal CO(6-5)
emission than expected owing either to sizes smaller than the local Jeans mass
or to a pressure support mechanism other than turbulence.


title: The number of cosmic string loops

abstract:
  Using recent simulation results, we provide the mass and speed spectrum of
cosmic string loops. This is the quantity of primary interest for many
phenomenological signatures of cosmic strings, and it can be accurately
predicted using recently acquired detailed knowledge of the loop production
function. We emphasize that gravitational smoothing of long strings does not
play any role in determining the total number of existing loops. We derive a
bound on the string tension imposed by recent constraints on the stochastic
gravitational wave background from pulsar timing arrays, finding $G\mu \leq
2.8\times 10^{-9}$. We also provide a derivation of the Boltzmann equation for
cosmic string loops in the language of differential forms.


title:
Tight Correlations Between Massive Galaxy Structural Properties and
  Dynamics: The Mass Fundamental Plane Was in Place by z~2

abstract:
  The Fundamental Plane (FP) is an empirical relation between the size, surface
brightness, and velocity dispersion of early-type galaxies. This relation has
been studied extensively for early-type galaxies in the local universe to
constrain galaxy formation mechanisms. The evolution of the zeropoint of this
plane has been extended to high redshifts to study the luminosity evolution of
massive galaxies, under the assumption of structural homology. In this work, we
assess this assumption by replacing surface brightness with stellar mass
density and present the evolution of the "mass FP" for massive, quiescent
galaxies since z~2. By accounting for stellar populations, we thereby isolate
and trace structural and dynamical evolution. Despite the observed dramatic
evolution in the sizes and morphologies of massive galaxies since z~3, we find
that quiescent galaxies lie on the mass FP out to z~2. In contrast with ~1.4
dex evolution in the luminosity FP, average residuals from the z~0 mass FP are
less than ~0.15 dex since z~2. Assuming the Hyde & Bernardi (2009) mass FP
slope, we find that this minimal offset scales as (1+z)^{-0.095+/-0.043}. This
result lends credence to previous studies that derived luminosity evolution
from the FP. Therefore, despite their compact sizes and suggestions that
massive galaxies are more disk-like at z~2, the relationship between their
dynamics and structural properties are consistent with local early-type
galaxies. Finally, we find no strong evidence for a tilt of the mass FP
relative to the Virial plane, but emphasize the need for full models including
selection biases to fully investigate this issue.


title:
Angular fluctuations of a multi-component order describe the pseudogap
  regime of the cuprate superconductors

abstract:
  The hole-doped cuprate high temperature superconductors enter the pseudogap
regime as their superconducting critical temperature, $T_c$, falls with
decreasing hole density. Experiments have probed this regime for over two
decades, but we argue that decisive new information has emerged from recent
X-ray scattering experiments (arXiv:1207.0915, arXiv:1206.4333,
arXiv:1207.3667). The experiments observe incommensurate charge density wave
fluctuations whose strength rises gradually over a wide temperature range above
$T_c$, but then decreases as the temperature is lowered below $T_c$. We propose
a theory in which the superconducting and charge-density wave orders exhibit
angular fluctuations in a 6-dimensional space. The theory provides a natural
quantitative fit to the X-ray data, and can be a basis for understanding other
characteristics of the pseudogap.


title: Dark Matter from Hidden Forces

abstract:
  We examine the possibility that dark matter may be the manifestation of dark
forces of a hidden sector, i.e. "Dark Force = Dark Matter." As an illustrative
and minimal example we consider the hidden SU(2)_h x U(1)_h gauge group. The
hidden dynamics is indirectly coupled to the Standard Model (SM) through
kinetic mixing of U(1)_h with the U(1)_Y of hypercharge. We assume a hidden
symmetry breaking pattern analogous to that of the SM electroweak symmetry,
augmented with an extra scalar that allows both the "hidden Z boson" Z_h and
the "hidden photon" \gamma_h to be massive. The "hidden W" bosons W_h are dark
matter in this scenario. This setup can readily accommodate a potential direct
detection signal for dark matter at ~10 GeV from CDMSII-Si data. For some
choices of parameters, the model can lead to signals both in "dark matter beam"
experiments, from Z_h\to W_h W_h, as well as in experiments that look for
visible signals of dark photons, mediated by \gamma_h. Other possible
phenomenological consequences are also briefly discussed.


title: A halo bias function measured deeply into voids without stochasticity

abstract:
  We study the relationship between dark-matter haloes and matter in the MIP
$N$-body simulation ensemble, which allows precision measurements of this
relationship, even deeply into voids. What enables this is a lack of
discreteness, stochasticity, and exclusion, achieved by averaging over hundreds
of possible sets of initial small-scale modes, while holding fixed large-scale
modes that give the cosmic web. We find (i) that dark-matter-halo formation is
greatly suppressed in voids; there is an exponential downturn at low densities
in the otherwise power-law matter-to-halo density bias function. Thus, the
rarity of haloes in voids is akin to the rarity of the largest clusters, and
their abundance is quite sensitive to cosmological parameters. The exponential
downturn appears both in an excursion-set model, and in a model in which
fluctuations evolve in voids as in an open universe with an effective
$\Omega_m$ proportional to a large-scale density. We also find that (ii) haloes
typically populate the average halo-density field in a super-Poisson way, i.e.
with a variance exceeding the mean; and (iii) the rank-order-Gaussianized halo
and dark-matter fields are impressively similar in Fourier space. We compare
both their power spectra and cross-correlation, supporting the conclusion that
one is roughly a strictly-increasing mapping of the other. The MIP ensemble
especially reveals how halo abundance varies with `environmental' quantities
beyond the local matter density; (iv) we find a visual suggestion that at fixed
matter density, filaments are more populated by haloes than clusters.


title: The global anomaly of the self-dual field in general backgrounds

abstract:
  We prove a formula for the global gravitational anomaly of the self-dual
field theory in the presence of background gauge fields, assuming the results
of arXiv:1110.4639. Along the way, we also clarify various points about the
self-dual field theory. In particular, we give a general definition of the
theta characteristic entering its partition function and settle the issue of
its possible metric dependence. We treat the cohomological version of type IIB
supergravity as an example of the formalism: a mixed gauge-gravitational global
anomaly, occurring when the B-field and Ramond-Ramond 2-form gauge fields have
non-trivial Wilson lines, cancels provided a certain cobordism group vanishes.


title:
The Violent Youth of Bright and Massive Cluster Galaxies and their
  Maturation over 7 Billion Years

abstract:
  In this study we investigate the formation and evolution mechanisms of the
brightest cluster galaxies (BCGs) over cosmic time. At high redshift
($z\sim0.9$), we selected BCGs and most massive cluster galaxies (MMCGs) from
the Cl1604 supercluster and compared them to low-redshift ($z\sim0.1$)
counterparts drawn from the MCXC meta-catalog, supplemented by SDSS imaging and
spectroscopy. We observed striking differences in the morphological, color,
spectral, and stellar mass properties of the BCGs/MMCGs in the two samples.
High-redshift BCGs/MMCGs were, in many cases, star-forming, late-type galaxies,
with blue broadband colors, properties largely absent amongst the low-redshift
BCGs/MMCGs. The stellar mass of BCGs was found to increase by an average factor
of $2.51\pm0.71$ from $z\sim0.9$ to $z\sim0.1$. Through this and other
comparisons we conclude that a combination of major merging (mainly wet or
mixed) and \emph{in situ} star formation are the main mechanisms which build
stellar mass in BCGs/MMCGs. The stellar mass growth of the BCGs/MMCGs also
appears to grow in lockstep with both the stellar baryonic and total mass of
the cluster. Additionally, BCGs/MMCGs were found to grow in size, on average, a
factor of $\sim3$, while their average S\'ersic index increased by $\sim$0.45
from $z\sim0.9$ to $z\sim0.1$, also supporting a scenario involving major
merging, though some adiabatic expansion is required. These observational
results are compared to both models and simulations to further explore the
implications on processes which shape and evolve BCGs/MMCGs over the past
$\sim$7 Gyr.


title: A compact 341 model at TeV scale

abstract:
  We build a gauge model based on the SU(3)_c x SU(4)_L x U(1)_X symmetry where
the scalar spectrum needed to generate gauge boson and fermion masses has a
smaller scalar content than usually assumed in literature. We compute the
running of its abelian gauge coupling and show that a Landau pole shows up at
the TeV scale, a fact that we use to consistently implement those fermion
masses that are not generated by Yukawa interactions, including neutrino
masses. This is appropriately achieved by non renormalizable effective
operators, suppressed by the Landau pole scale. Also, SU(3)_c x SU(3)_L x
U(1)_N models embedded in this gauge structure are bound to be strongly coupled
at this same energy scale, contrary to what is generally believed, and neutrino
mass generation is rather explained through the same effective operators used
in the larger gauge group. Besides, their nice features, as the existence of
cold dark matter candidates and the ability to reproduce the observed standard
model Higgs-like phenomenology, are automatically inherited by our model.
Finally, our results imply that this model is constrained to be observed or
discarded soon, since it must be realized at the currently probed energy scale
in LHC.


title:
A large-scale galaxy structure at z = 2.02 associated with the radio
  galaxy MRC0156-252

abstract:
  We present the spectroscopic confirmation of a structure of galaxies
surrounding the radio galaxy MRC0156-252 at z = 2.02. The structure was
initially discovered as an overdensity of both near-infrared selected z > 1.6
and mid-infrared selected z > 1.2 galaxy candidates. We used the VLT/FORS2
multi-object spectrograph to target ~80 high-redshift galaxy candidates, and
obtain robust spectroscopic redshifts for more than half the targets. The
majority of the confirmed sources are star-forming galaxies at z > 1.5. In
addition to the radio galaxy, two of its close-by companions (< 6'') also show
AGN signatures. Ten sources, including the radio galaxy, lie within |z - 2.020
| < 0.015 (i.e., velocity offsets < 1500 km/s) and within projected 2 Mpc
comoving of the radio galaxy. Additional evidence suggests not only that the
galaxy structure associated with MRC0156-252 is a forming galaxy cluster but
also that this structure is most probably embedded in a larger scale structure.


title:
Radial weak solutions for the Perona-Malik equation as a differential
  inclusion

abstract:
  The Perona-Malik equation is an ill-posed forward-backward parabolic equation
with major application in image processing. In this paper we study the
Perona-Malik type equation and show that, in all dimensions, there exist
infinitely many radial weak solutions to the homogeneous Neumann boundary
problem for any smooth nonconstant radially symmetric initial data. Our
approach is to reformulate the $n$-dimensional equation into a one-dimensional
equation, to convert the one-dimensional problem into a differential inclusion
problem, and to apply a Baire's category method to generate infinitely many
solutions.


title:
The BFKL equation, Mueller-Navelet jets and single-valued harmonic
  polylogarithms

abstract:
  We introduce a generating function for the coefficients of the leading
logarithmic BFKL Green's function in transverse-momentum space, order by order
in alpha_s, in terms of single-valued harmonic polylogarithms. As an
application, we exhibit fully analytic azimuthal-angle and transverse-momentum
distributions for Mueller-Navelet jet cross sections at each order in alpha_s.
We also provide a generating function for the total cross section valid to any
number of loops.


title: Effects of thermal gradients on total internal reflection corner cubes

abstract:
  Uncoated corner cube retroreflectors (CCRs) operating via total internal
reflection (TIR) are less susceptible to internal heating than their
metal-coated analogs, lacking an absorber on the rear surface. Even so,
environments that induce differential heating within the CCR will result in
thermal lensing of the incident wavefront, introducing aberrations that will
generally reduce the central irradiance of the polarization-sensitive far-field
diffraction pattern (FFDP). In this paper, we characterize the sensitivity of
TIR CCRs to axial and radial thermal gradients. We present simulated FFDPs for
key input polarizations and incidence angles and provide a generalized analytic
model that approximates the behavior of the central irradiance as temperature
differences are introduced.


title:
Polarization and far-field diffraction patterns of total internal
  reflection corner cubes

abstract:
  Many corner cube prisms, or retroreflectors, employ total internal reflection
(TIR) via uncoated rear surfaces. The different elliptical polarization states
emerging from the six unique paths through the corner cube complicate the
far-field diffraction pattern by introducing various phase delays between the
six paths. In this paper, we present a computational framework to evaluate
polarization through TIR corner cubes for arbitrary incidence angles and input
polarization states, presenting example output for key normal-incidence
conditions. We also describe a method to produce far-field diffraction patterns
resulting from the polarization analysis, presenting representative
images---broken into orthogonal polarizations, and characterizing key cases.
Laboratory confirmation is also presented for both polarization states and
far-field diffraction patterns.


title: An Inter-lingual Reference Approach For Multi-Lingual Ontology Matching

abstract:
  Ontologies are considered as the backbone of the Semantic Web. With the
rising success of the Semantic Web, the number of participating communities
from different countries is constantly increasing. The growing number of
ontologies available in different natural languages leads to an
interoperability problem. In this paper, we discuss several approaches for
ontology matching; examine similarities and differences, identify weaknesses,
and compare the existing automated approaches with the manual approaches for
integrating multilingual ontologies. In addition to that, we propose a new
architecture for a multilingual ontology matching service. As a case study we
used an example of two multilingual enterprise ontologies - the university
ontology of Freie Universitaet Berlin and the ontology for Fayoum University in
Egypt.


title: Inside the clustering threshold for random linear equations

abstract:
  We study a random system of $cn$ linear equations over $n$ variables in
GF(2), where each equation contains exactly $r$ variables; this is equivalent
to $r$-XORSAT. \cite{ikkm,amxor} determined the clustering threshold, $c^*_r$:
if $c=c^*_r+\e$ for any constant $\e>0$, then \aas the solutions partition into
well-connected, well-separated {\em clusters} (with probability tending to 1 as
$n\rightarrow\infty$). This is part of a general clustering phenomenon which is
hypothesized to arise in most of the commonly studied models of random
constraint satisfaction problems, via sophisticated but mostly non-rigorous
techniques from statistical physics. We extend that study to the range
$c=c^*_r+o(1)$, showing that if $c=c^*_r+n^{-\d}, \d>0$, then the connectivity
parameter of each $r$-XORSAT cluster is $n^{\Theta(\d)}$, as compared to
$O(\log n)$ when $c=c^*_r+\e$. This means that one can move between any two
solutions in the same cluster via a sequence of solutions where consecutive
solutions differ on at most $n^{\Theta(\d)}$ variables; this is tight up to the
implicit constant. In contrast, moving to a solution in another cluster
requires that some pair of consecutive solutions differ in at least
$n^{1-O(\d)}$ variables.
  Along the way, we prove that in a random $r$-uniform hypergraph with
edge-density $n^{-\d}$ above the $k$-core threshold, \aas every vertex not in
the $k$-core can be removed by a sequence of $n^{\Theta(\d)}$ vertex-deletions
in which the deleted vertex has degree less than $k$; again, this is tight up
to the implicit constant.


title:
Quantized Faraday effect in (3+1)-dimensional and (2+1)-dimensional
  systems

abstract:
  We study Faraday rotation in the quantum relativistic limit. Starting from
the photon self-energy in the presence of a constant magnetic field the
rotation of the polarization vector of a plane electromagnetic wave which
travel along the fermion-antifermion gas is studied. The connection between
Faraday Effect and Quantum Hall Effect (QHE) is discussed. The Faraday Effect
is also investigated for a massless relativistic (2D+1)-dimensional fermion
system which is derived by using the compactification along the dimension
parallel to the magnetic field. The Faraday angle shows a quantized behavior as
Hall conductivity in two and three dimensions.


title: Proximity Enhanced Quantum Spin Hall State in Graphene

abstract:
  Graphene is the first model system of two-dimensional topological insulator
(TI), also known as quantum spin Hall (QSH) insulator. The QSH effect in
graphene, however, has eluded direct experimental detection because of its
extremely small energy gap due to the weak spin-orbit coupling. Here we predict
by ab initio calculations a giant (three orders of magnitude) proximity induced
enhancement of the TI energy gap in the graphene layer that is sandwiched
between thin slabs of Sb2Te3 (or MoTe2). This gap (1.5 meV) is accessible by
existing experimental techniques, and it can be further enhanced by tuning the
interlayer distance via compression. We reveal by a tight-binding study that
the QSH state in graphene is driven by the Kane-Mele interaction in competition
with Kekul\'e deformation and symmetry breaking. The present work identifies a
new family of graphene-based TIs with an observable and controllable bulk
energy gap in the graphene layer, thus opening a new avenue for direct
verification and exploration of the long-sought QSH effect in graphene.


title: Relativistic Einstein-Podolsky-Rosen correlations and localization

abstract:
  We calculate correlation functions for a relativistic
Einstein-Podolsky-Rosen-type experiment with massive Dirac particles. We take
the influence of the Newton-Wigner localization into account and perform the
calculations for a couple of physically interesting states.


title: Introduction to the Symbolic Integration System

abstract:
  Symbolic integration is an important module of a typical Computer Algebra
System. As for now, Mathematica, Matlab, Maple and Sage are all mainstream CAS.
They share the same framework for symbolic integration at some points. In this
book first we review the state of the art in the field of CAS. Then we focus on
typical frameworks of the current symbolic integration systems and summarize
the main mathematical theories behind these frameworks. Based on the
open-source computer algebra system maTHmU developed by our team in our
university, we propose a potential framework to improve the performance of the
current symbolic integration system.


title: A non-laminar dynamical Green current

abstract:
  A holomorphic endomorphism f of CP^2 admits a Julia set J_1, defined as usual
to be the locus of non-normality of its iterates, and a (typically) smaller
Julia set J_2, which is essentially the closure of the set of repelling
periodic orbits. The question has been raised whether J_1\J_2 is filled
(possibly in a measure-theoretic sense) with "Fatou subvarieties" along which
the dynamics is locally equicontinuous. In this article we construct examples
showing that this is not the case in general


title:
Ab-initio calculation of the effective on-site Coulomb interaction
  parameters for half-metallic magnets

abstract:
  Correlation effects play an important role in the electronic structure of
half-metallic (HM) magnets. In particular, they give rise to non-quasiparticle
states above (or below) the Fermi energy at finite temperatures that reduce the
spin polarization and, as a consequence, the efficiency of spintronics devices.
Employing the constrained random-phase approximation (cRPA) within the
full-potential linearized augmented-plane-wave (FLAPW) method using maximally
localized Wannier functions, we calculate the strength of the effective on-site
Coulomb interaction (Hubbard $U$ and Hund exchange $J$) between localized
electrons in different classes of HM magnets considering: (i)
\emph{sp}-electron ferromagnets in rock-salt structure, (ii) zincblende
3\emph{d} binary ferromagnets, as well as (iii) ferromagnetic and ferrimagnetic
semi- and full-Heusler compounds.


title: Nanoscopic friction under electrochemical control

abstract:
  We propose a theoretical model of friction under electrochemical conditions
focusing on the interaction of a force microscope tip with adsorbed polar
molecules of which the orientation depends on the applied electric field. We
demonstrate that the dependence of friction force on the electric field is
determined by the interplay of two channels of energy dissipation: (i) the
rotation of dipoles and (ii) slips of the tip over potential barriers. We
suggest a promising strategy to achieve a strong dependence of nanoscopic
friction on the external field based on the competition between long range
electrostatic interactions and short range chemical interactions between tip
and adsorbed polar molecules.


title:
Independent and Hitting Sets of Rectangles Intersecting a Diagonal Line
  : Algorithms and Complexity

abstract:
  Finding a maximum independent set (MIS) of a given fam- ily of axis-parallel
rectangles is a basic problem in computational geom- etry and combinatorics.
This problem has attracted significant atten- tion since the sixties, when
Wegner conjectured that the corresponding duality gap, i.e., the maximum
possible ratio between the maximum independent set and the minimum hitting set
(MHS), is bounded by a universal constant. An interesting special case, that
may prove use- ful to tackling the general problem, is the
diagonal-intersecting case, in which the given family of rectangles is
intersected by a diagonal. Indeed, Chepoi and Felsner recently gave a factor 6
approximation algorithm for MHS in this setting, and showed that the duality
gap is between 3/2 and 6. In this paper we improve upon these results. First we
show that MIS in diagonal-intersecting families is NP-complete, providing one
smallest subclass for which MIS is provably hard. Then, we derive an
$O(n^2)$-time algorithm for the maximum weight independent set when, in
addition the rectangles intersect below the diagonal. This improves and extends
a classic result of Lubiw, and amounts to obtain a 2-approximation algo- rithm
for the maximum weight independent set of rectangles intersecting a diagonal.
Finally, we prove that for diagonal-intersecting families the duality gap is
between 2 and 4. The upper bound, which implies an approximation algorithm of
the same factor, follows from a simple com- binatorial argument, while the
lower bound represents the best known lower bound on the duality gap, even in
the general case.


title: Magnetic and transport properties of Mn2CoAl oriented thin films

abstract:
  The structure, magnetic and transport properties of thin films of the Heusler
ferrimagnet Mn_{2}CoAl have been investigated for properties related to spin
gapless semiconductors. Oriented films were grown by molecular beam epitaxy on
GaAs substrates and the structure was found to transform from tetragonal to
cubic for increasing annealing temperature. The anomalous Hall resistivity is
found to be proportional to the square of the longitudinal resistivity and
magnetization expected for a topological Berry curvature origin. A delicate
balance of the spin-polarized carrier type when coupled with voltage
gate-tuning could significantly impact advanced electronic devices.


title: Reflectionless measures for Calder\'{o}n-Zygmund operators

abstract:
  We study the properties of reflectionless measures for a Calder\'{o}n-Zygmund
operator T. Roughly speaking, these are measures $\mu$ for which T(\mu)
vanishes (in a weak sense) on the support of the measure. We describe the
relationship between certain well-known problems in harmonic analysis and
geometric measure theory and the classification of reflectionless measures. As
an application of our theory, we give a new proof of a recent theorem of
Eiderman, Nazarov, and Volberg, which states that in $\mathbb{R}^d$, the
s-dimensional Riesz transform of a non-trivial $s$-dimensional measure is
unbounded if $s\in (d-1,d)$.


title:
High resolution photoassociation spectroscopy of the $^{6}$Li$_2$
  $1^{3}\Sigma_{g}^{+}$ state

abstract:
  We present experimental observations of seven vibrational levels $v'=20-26$
of the $1^{3}\Sigma_{g}^{+}$ excited state of Li$_2$ molecules by the
photoassociation (PA) of a degenerate Fermi gas of $^6$Li atoms. For each
vibrational level, we resolve the rotational structure using a Feshbach
resonance to enhance the PA rates from p-wave collisions. We also, for the
first time, determine the spin-spin and spin-rotation interaction constants for
this state. The absolute uncertainty of our measurements is $\pm 0.00002$
cm$^{-1}$ ($\pm 600$ kHz). We use these new data to further refine an analytic
potential for this state.


title:
A Systematic Retrieval Analysis of Secondary Eclipse Spectra II: A
  Uniform Analysis of Eight Planets and Their C to O Ratios

abstract:
  Secondary eclipse spectroscopy provides invaluable insights into the
temperatures and compositions of exoplanetary atmospheres. We carry out a
systematic temperature and abundance retrieval analysis of nine exoplanets
(HD189733b, HD209458b, HD149026b, GJ436b, WASP-12b, WASP-19b, WASP-43b,
TrES-2b, and TrES-3b) observed in secondary eclipse using a combination of
space- and ground-based facilities. Our goal with this analysis is to provide a
consistent set of temperatures and compositions from which self-consistent
models can be compared and to probe the underlying processes that shape these
atmospheres. This paper is the second in a three part series of papers
exploring the retrievability of temperatures and abundances from secondary
eclipse spectra and the implications of these results for the chemistry of
exoplanet atmospheres. In this investigation we present a catalogue of
temperatures and abundances for H$_2$O, CH$_4$, CO, and CO$_2$. We find that
our temperatures and abundances are generally consistent with those of previous
studies, although we do not find any statistically convincing evidence for
super-solar C to O ratios (e.g., solar C/O falls in the 1-sigma confidence
intervals in eight of the nine planets in our sample). Furthermore, within our
sample we find little evidence for thermal inversions over a wide range of
effective temperatures (with the exception of HD209458b), consistent with
previous investigations. The lack of evidence for inversions for most planets
in our sample over such a wide range of effective temperatures provides
additional support for the hypothesis that TiO is unlikely to be the absorber
responsible for the formation of these inversions.


title:
Historical account and ultra-simple proofs of Descartes's rule of signs,
  De Gua, Fourier, and Budan's rule

abstract:
  It may seem a funny notion to write about theorems as old and rehashed as
Descartes's rule of signs, De Gua's rule or Budan's. Admittedly, these theorems
were proved numerous times over the centuries. However, despite the popularity
of these results, it seems that no thorough and up-to-date historical account
of their proofs has ever been given, nor has an effort been made to reformulate
the oldest demonstrations in modern terms. The motivation of this paper is to
put these strongly related theorems back in their historical perspective. More
importantly, we suggest a way to understand Descartes's original statement,
which yet remains somewhat of an enigma. We found that this question is related
to a certain way of counting the alternations and permanences of signs of the
polynomial coefficients, and may have been the convention used by Descartes.
Remarkably, this convention not only provides a ultra-simple proof of
Descartes's rule, but it can also be used to simplify the proofs of the titular
theorems. Without claiming to be exhaustive, we shall present in this paper an
historical account of these theorems and their proofs, and clarify their mutual
relation. We will explain how a suitable convention can help understand the
original statement of Descartes and greatly simplify its proof, as well as the
proofs of the above-mentioned theorems. With the exception of the proof of
Fourier's theorem and its generalizations, which run on rudiments of
infinitesimal calculus (Taylor's theorem), the proposed demonstrations are so
short and elementary they could be taught at the undergraduate level.


title:
The REgolith X-Ray Imaging Spectrometer (REXIS) for OSIRIS-REx:
  Identifying Regional Elemental Enrichment on Asteroids

abstract:
  The OSIRIS-REx Mission was selected under the NASA New Frontiers program and
is scheduled for launch in September of 2016 for a rendezvous with, and
collection of a sample from the surface of asteroid Bennu in 2019. 101955 Bennu
(previously 1999 RQ36) is an Apollo (near-Earth) asteroid originally discovered
by the LINEAR project in 1999 which has since been classified as a potentially
hazardous near-Earth object. The REgolith X-Ray Imaging Spectrometer (REXIS)
was proposed jointly by MIT and Harvard and was subsequently accepted as a
student led instrument for the determination of the elemental composition of
the asteroid's surface as well as the surface distribution of select elements
through solar induced X-ray fluorescence. REXIS consists of a detector plane
that contains 4 X-ray CCDs integrated into a wide field coded aperture
telescope with a focal length of 20 cm for the detection of regions with
enhanced abundance in key elements at 50 m scales. Elemental surface
distributions of approximately 50-200 m scales can be detected using the
instrument as a simple collimator. An overview of the observation strategy of
the REXIS instrument and expected performance are presented here.


title: Two-dimensional wave propagation in layered periodic media

abstract:
  We study two-dimensional wave propagation in materials whose properties vary
periodically in one direction only. High order homogenization is carried out to
derive a dispersive effective medium approximation. One-dimensional materials
with constant impedance exhibit no effective dispersion. We show that a new
kind of effective dispersion may arise in two dimensions, even in materials
with constant impedance. This dispersion is a macroscopic effect of microscopic
diffraction caused by spatial variation in the sound speed. We analyze this
dispersive effect by using high-order homogenization to derive an anisotropic,
dispersive effective medium. We generalize to two dimensions a homogenization
approach that has been used previously for one-dimensional problems.
Pseudospectral solutions of the effective medium equations agree to high
accuracy with finite volume direct numerical simulations of the
variable-coefficient equations.


title:
On the BCS-BEC crossover in the Spin-Polarized Attractive Hubbard Model
  at T=0

abstract:
  The influence of the Zeeman magnetic field ($h$) on the ground state
evolution of superfluid properties from the weak coupling (BCS like) to the
strong coupling limit of tightly bound local pairs (LP) with increasing
attraction has been studied. The analysis was carried out within the
spin-polarized attractive Hubbard model, for a fixed number of particles and a
$d=3$ simple cubic lattice. The broken symmetry Hartree approximation was used.
For strong attraction and in the dilute limit, the homogeneous magnetized
superconducting phase (SC$_M$) was found in the $(h-|U|)$ and ($P-|U|$)
diagrams.


title:
Stability of superfluid phases in the 2D Spin-Polarized Attractive
  Hubbard Model

abstract:
  We study the evolution from the weak coupling (BCS-like limit) to the strong
coupling limit of tightly bound local pairs (LP's) with increasing attraction,
in the presence of the Zeeman magnetic field ($h$) for $d=2$, within the
spin-polarized attractive Hubbard model. The broken symmetry Hartree
approximation {as well as the} strong coupling expansion are used. We also
apply the Kosterlitz-Thouless (KT) scenario to determine the phase coherence
temperatures. For spin independent hopping integrals
($t^{\uparrow}=t^{\downarrow}$), we find no stable homogeneous polarized
superfluid (SC$_M$) state in the ground state for the strong attraction and
obtain that for a two-component Fermi system on a 2D lattice with population
imbalance, phase separation (PS) is favoured for a fixed particle
concentration, even on the LP (BEC) side. We also examine the influence of spin
dependent hopping integrals (mass imbalance) on the stability of the SC$_M$
phase. We find a topological quantum phase transition (Lifshitz type) from the
unpolarized superfluid phase (SC$_0$) to SC$_M$ and tricritical points in the
($h-|U|$) and ($t^{\uparrow} / t^{\downarrow} - |U|$) ground state phase
diagrams. We also construct the finite temperature phase diagrams for both
$t^{\uparrow} = t^{\downarrow}$ and $t^{\uparrow}\neq t^{\downarrow}$ and
analyze the possibility of occurrence of a spin polarized KT superfluid.


title: On q-Series Identities Related to Interval Orders

abstract:
  We prove several power series identities involving the refined generating
function of interval orders, as well as the refined generating function of the
self-dual interval orders. These identities may be expressed as $\sum_{n\ge
0}(1/p;1/q)_n= \sum_{n\ge 0} pq^n(p;q)_n(q;q)_n$ and $\sum_{n\ge 0}
(-1)^n(1/p;1/q)_n= \sum_{n\ge 0} pq^n(p;q)_n(-q;q)_n =\sum_{n\ge 0}
(q/p)^n(p;q^2)_n$, where the equalities apply to the (purely formal) power
series expansions of the above expressions at $p=q=1$, as well as at other
suitable roots of unity.


title: Betatron modulation of microwave instability in small isochronous ring

abstract:
  A novel coupling of the transverse betatron motion to the longitudinal
microwave instability is studied. Besides the radial coherent dipole mode space
charge field, simulation and theoretical studies in this paper show that the
longitudinal coherent dipole mode space charge field due to centroid wiggles
also plays an important role in the isochronous regime, it induces betatron
oscillation frequencies in temporal evolutions of spectra of longitudinal
charge densities, radial centroid offsets and coherent energy deviations of
local centroids.