title: Minimal Z' models and the 125 GeV Higgs boson

abstract:
  The 1-loop renormalization group equations for the minimal Z' models
encompassing a type-I seesaw mechanism are studied in the light of the 125 GeV
Higgs boson discovery. This model is taken as a benchmark for the general case
of singlet extensions of the standard model. The most important result is that
negative scalar mixing angles are favoured with respect to positive values.
Further, a minimum value for the latter exists, as well as a maximum value for
the masses of the heavy neutrinos, depending on the vacuum expectation value of
the singlet scalar.


title: On Generalized Weighted Hilbert Matrices

abstract:
  In this paper, we study spectral properties of generalized weighted Hilbert
matrices. In particular, we establish results on the spectral norm,
determinant, as well as various relations between the eigenvalues and
eigenvectors of such matrices. We also study the asymptotic behaviour of the
spectral norm of the classical Hilbert matrix.


title: Quantum metamaterial without local control

abstract:
  A quantum metamaterial can be implemented as a quantum coherent 1D array of
qubits placed in a transmission line. The properties of quantum metamaterials
are determined by the local quantum state of the system. Here we show that a
spatially-periodic quantum state of such a system can be realized without
direct control of the constituent qubits, by their interaction with the
initializing ("priming") pulses sent through the system in opposite directions.
The properties of the resulting quantum photonic crystal are determined by the
choice of the priming pulses. This proposal can be readily generalized to other
implementations of quantum metamaterials.


title: Dark matter within the minimal flavour violation ansatz

abstract:
  Minimal Flavour Violation hypothesis can provide an attractive framework for
Dark Matter (DM). We consider scalar DM candidates carrying flavour quantum
numbers and whose representation under the flavour group guarantees DM
stability. They interact with the Standard Model fields through Higgs portal at
renormalisable level and also to quarks through dimension-6 operators. We
provide a systematic analysis of the viable parameter space for the DM fields,
which are triplet of the flavour group, considering several DM-quark
interactions. In this framework, we analyse in which cases the viable parameter
space differs from Higgs portal models thanks to the underlying flavour
structure. In contrast to minimal Higgs portal scenarios, we find that light DM
in the GeV mass range as well as heavier candidates above Higgs resonance could
be allowed by colliders, direct and indirect DM detection searches as well as
flavour constraints. The large mass regime above the top mass could even be
beyond the reach of future experiments such as Xenon 1T.


title:
Lyapunov Exponents of Rank 2-Variations of Hodge Structures and Modular
  Embeddings

abstract:
  If the monodromy representation of a VHS over a hyperbolic curve stabilizes a
rank two subspace, there is a single non-negative Lyapunov exponent associated
with it. We derive an explicit formula using only the representation in the
case when the monodromy is discrete.


title:
Strategies for the Detection of Gamma Rays from Dark Matter Annihilation
  Towards the Galactic Center Region with the High Energy Stereoscopic System

abstract:
  The central region of the dark matter halo of the Milky Way is a promising
target for a search for a particle dark matter annihilation signal. The
H.E.S.S. Collaboration has published a search for a photon flux originating
from dark matter particles annihilating in the galactic center region. No
significant excess was observed and upper limits on the velocity averaged dark
matter self annihilation cross section were derived. The limits exclude the
self annihilation of dark matter particles in the $\sim 1$ TeV to $\sim 4$ TeV
mass range with a velocity averaged annihilation cross section larger than
$\sim 3\cdot 10^{-25}\:\mathrm{cm^3/s}$, i.e. about one order of magnitude
above the prediction for a thermal relic dark matter particle. A detailed and
realistic Monte Carlo study of new strategies for the search for a particle
dark matter annihilation signal from the Milky Way dark matter halo with the
High Energy Stereoscopic System is presented and the sensitivity of different
experimental approaches is compared.


title:
Embedded Online Optimization for Model Predictive Control at Megahertz
  Rates

abstract:
  Faster, cheaper, and more power efficient optimization solvers than those
currently offered by general-purpose solutions are required for extending the
use of model predictive control (MPC) to resource-constrained embedded
platforms. We propose several custom computational architectures for different
first-order optimization methods that can handle linear-quadratic MPC problems
with input, input-rate, and soft state constraints. We provide analysis
ensuring the reliable operation of the resulting controller under reduced
precision fixed-point arithmetic. Implementation of the proposed architectures
in FPGAs shows that satisfactory control performance at a sample rate beyond 1
MHz is achievable even on low-end devices, opening up new possibilities for the
application of MPC on embedded systems.


title: Fisher-KPP propagation in the presence of a line: further effects

abstract:
  This paper is a continuation of [2] where a new model of biological invasions
in the plane directed by a line was introduced. Here we include new features
such as transport and reaction terms on the line. Their interaction with the
pure diffusivity in the plane is quantified in terms of enhancement of the
propagation speed. We establish conditions that determine whether the spreading
speed exceeds the standard Fisher KPP invasion speed. These conditions involve
the ratio of the diffusivities on the line and in the field, the transport term
and the reactions. We derive the asymptotic behaviour for large diffusions or
large transports. We also discuss the biological interpretation of these
findings.


title: Search for rare $B^0_{(s)}\rightarrow \mu^+ \mu^- \mu^+ \mu^-$ decays

abstract:
  \noindent A search for the decays $B^0_{s}\rightarrow \mu^+ \mu^- \mu^+
\mu^-$ and $B^0 \rightarrow \mu^+ \mu^- \mu^+ \mu^-$ is performed using data,
corresponding to an integrated luminosity of
1.0\ensuremath{\{\,fb}^{-1}}\xspace, collected with the LHCb detector in 2011.
The number of candidates observed is consistent with the expected background
and, assuming phase-space models of the decays, limits on the branching
fractions are set: \{${\ensuremath{\cal B}\xspace}(B^0_{s}\rightarrow \mu^+
\mu^- \mu^+ \mu^-) < 1.6 \ (1.2) \times 10^{-8}$} and \{${\ensuremath{\cal
B}\xspace}(B^0 \rightarrow \mu^+ \mu^- \mu^+ \mu^-)< 6.6 \ (5.3) \times
10^{-9}$} at 95\,% (90\,%) confidence level. In addition, limits are set in the
context of a supersymmetric model which allows for the $B^0_{(s)}$ meson to
decay into a scalar ($S$) and pseudoscalar particle ($P$), where $S$ and $P$
have masses of 2.5 GeV and 214.3 MeV, respectively, both resonances decay into
$\mu^+\mu^-$. The branching fraction limits for these decays are
\{${\ensuremath{\cal B}\xspace}(\ensuremath{B^0_{s}\rightarrow SP}\xspace) <
1.6 \ (1.2) \times 10^{-8}$} and \{${\ensuremath{\cal
B}\xspace}(\ensuremath{B^0\rightarrow SP}\xspace)< 6.3 \ (5.1) \times 10^{-9}$}
at 95% (90%) confidence level.


title: On Large Deviation Property of Recurrence Times

abstract:
  We extend the study by Ornstein and Weiss on the asymptotic behavior of the
normalized version of recurrence times and establish the large deviation
property for a certain class of mixing processes. Further, an estimator for
entropy based on recurrence times is proposed for which large deviation
behavior is proved for stationary and ergodic sources satisfying similar mixing
conditions.


title:
Ground-Based Transit Spectroscopy of the Hot-Jupiter WASP-19b in the
  Near-Infrared

abstract:
  We present ground-based measurements of the transmission and emission spectra
of the hot-Jupiter WASP-19b in nine spectroscopic channels from 1.25 to 2.35
microns. The measurements are based on the combined analysis of time-series
spectroscopy obtained during two complete transits and two complete secondary
eclipses of the planet. The observations were performed with the MMIRS
instrument on the Magellan II telescope using the technique of multi-object
spectroscopy with wide slits. We compare the transmission and emission data to
theoretical models to constrain the composition and thermal structure of the
planet's atmosphere. Our measured transmission spectrum exhibits a scatter that
corresponds to 1.3 scale heights of the planet's atmosphere, which is
consistent with the size of spectral features predicted by theoretical models
for a clear atmosphere. We detected the secondary eclipses of the planet at
significances ranging from 2.2 to 14.4 sigma. The secondary eclipse depths, and
the significances of the detections increase towards longer wavelengths. Our
measured emission spectrum is consistent with a 2250 K effectively isothermal
1-D model for the planet's dayside atmosphere. This model also matches
previously published photometric measurements from the Spitzer Space Telescope
and ground-based telescopes. These results demonstrate the important role that
ground-based observations using multi-object spectroscopy can play in
constraining the properties of exoplanet atmospheres, and they also emphasize
the need for high-precision measurements based on observations of multiple
transits and eclipses.


title: A New Achievable Scheme for Interference Relay Channels

abstract:
  We establish an achievable rate region for discrete memoryless interference
relay channels that consist of two source-destination pairs and one or more
relays. We develop an achievable scheme combining Han-Kobayashi and noisy
network coding schemes. We apply our achievability to two cases. First, we
characterize the capacity region of a class of discrete memoryless interference
relay channels. This class naturally generalizes the injective deterministic
discrete memoryless interference channel by El Gamal and Costa and the
deterministic discrete memoryless relay channel with orthogonal receiver
components by Kim. Moreover, for the Gaussian interference relay channel with
orthogonal receiver components, we show that our scheme achieves a better sum
rate than that of noisy network coding.


title: Kalb-Ramond field localization on the Bloch brane

abstract:
  This work deals with new results on the Kalb-Ramond (KR) field localization
in braneworld models. We consider a five-dimensional warped spacetime with an
embedded 4D thick brane which is generated by two real scalar fields coupled
with gravity (the so called Bloch brane). We find a KR field zero mode
localized with the inclusion of the dilaton coupling. Analyzing the massive
spectrum, we detected a series of resonant modes that arise from the solutions
of the Schr\"odinger-like equation for KR field. The effects of the brane
thickness and of the dilaton coupling over the resonance structures are
determined. Such analysis is extended to the resonance lifetimes of the massive
modes, allowing a better understanding on the localization mechanism of the
model.


title: On the slowdown of random walk in random environment with bounded jumps

abstract:
  In this paper we prove that under certain assumptions the transient random
walk in random environment with bounded jumps (in $\mathbb{Z}$) grows much
slower than the speed $n$. Precisely, there is $0<s<1$, such that although
$X_n\rto$ we have
  $\frac{X_n}{n^{s'}}\rightarrow 0$ for $0<s<s'$ almost surely.


title:
On Match Lengths and the Asymptotic Behavior of Sliding Window
  Lempel-Ziv Algorithm for Zero Entropy Sequences

abstract:
  The Sliding Window Lempel-Ziv (SWLZ) algorithm has been studied from various
perspectives in information theory literature. In this paper, we provide a
general law which defines the asymptotics of match length for stationary and
ergodic zero entropy processes. Moreover, we use this law to choose the match
length $L_o$ in the almost sure optimality proof of Fixed Shift Variant of
Lempel-Ziv (FSLZ) and SWLZ algorithms given in literature. First, through an
example of stationary and ergodic processes generated by irrational rotation we
establish that for a window size of $n_w$ a compression ratio given by
$O(\frac{\log n_w}{{n_w}^a})$ where $a$ is arbitrarily close to 1 and $0 < a <
1$, is obtained under the application of FSLZ and SWLZ algorithms. Further, we
give a general expression for the compression ratio for a class of stationary
and totally ergodic processes with zero entropy.


title:
The Fundamental Theorem of Algebra and the Divergence of Reciprocals of
  Primes Looked at Through Bergman Spaces

abstract:
  Two well known facts from elementary number theory are proven by using
Bergman spaces.


title:
Transmitting signals over interstellar distances: Three approaches
  compared in the context of the Drake equation

abstract:
  I compare three methods for transmitting signals over interstellar distances:
radio transmitters, lasers and artificial transits. The quantitative comparison
is based on physical quantities depending on energy cost and transmitting time
L, the last parameter in the Drake equation. With our assumptions, radio
transmitters are the most energy-effective, while macro-engineered
planetary-sized objects producing artificial transits seem effective on the
long term to transmit an attention-getting signal for a time that might be much
longer than the lifetime of the civilization that produced the artifact.


title: Efficient Langevin Simulation of Coupled Classical Fields and Fermions

abstract:
  We introduce an efficient Langevin method to study bilinear Fermionic
Hamiltonians interacting with classical fields. Our method is suitable for very
large systems and offers high accuracy. To demonstrate the method, we study
complex non-coplanar chiral spin textures on the triangular Kondo lattice
model. We also explore non-equilibrium mesoscale physics such as chiral domain
coarsening and Z2 vortex annihilation.


title: K-Oscillons: Oscillons with Non-Canonical Kinetic Terms

abstract:
  Oscillons are long-lived, localized, oscillatory scalar field configurations.
In this work we derive a condition for the existence of small-amplitude
oscillons (and provide solutions) in scalar field theories with non-canonical
kinetic terms. While oscillons have been studied extensively in the canonical
case, this is the first example of oscillons in scalar field theories with
non-canonical kinetic terms. In particular, we demonstrate the existence of
oscillons supported solely by the non-canonical kinetic terms, without any need
for nonlinear terms in the potential. In the small-amplitude limit, we provide
an explicit condition for their stability in d+1 dimensions against
long-wavelength perturbations. We show that for d > 2, there exists a
long-wavelength instability which can lead to radial collapse of
small-amplitude oscillons.


title: VERITAS Results from Deep Exposure on the Distant FSRQ 4C +55.17

abstract:
  We present results from a deep VERITAS exposure of the distant (z=0.89)
flat-spectrum radio quasar (FSRQ) 4C +55.17. The high flux, hard index and
steady emission found by Fermi LAT observations make this blazar a promising
very-high-energy (VHE; E>100 GeV) candidate, offering a possibility to clarify
the location of FSRQ VHE emission. Non-detection supports the hypothesis that
any VHE gamma-rays are produced within and absorbed by the broad-line region
while VHE detection would support an emission region outside the broad line
region and far from the base of the jet. This FSRQ additionally provides the
possible means, by photon-photon pair production, to constrain the currently
available extragalactic background light (EBL) models out to the groundbreaking
redshift of z=0.89. The log-parabolic model that is fitted to the LAT photons
allows an extrapolation of the fit up to VHE while accounting for the gamma-ray
absorption by the EBL. The VERITAS upper limit derived from the deep exposure
is compared to this extrapolated VHE flux.


title:
Comprehensive abundance analysis of red giants in the open clusters NGC
  2527, 2682, 2482, 2539, 2335, 2251 and 2266

abstract:
  We have analyzed high-resolution echelle spectra of red giant members for
seven open clusters in the Galactic anticentre direction to explore their
chemical positions. Cluster membership has been confirmed by radial velocity.
The spread in temperatures and gravities being very small among the red giants,
nearly the same stellar lines were employed for all stars thereby reducing the
abundance errors: the errors of the average abundance for a cluster were
generally in the 0.02 to 0.05 dex range. Our present sample covers
Galactocentric distances of 8.3 to 11.3 kpc and an age range of 0.2 to 4.3 Gyr.
A careful comparison of our results for the cluster NGC 2682 (M 67) to other
high-resolution abundance studies in the literature shows general good
agreement for almost all elements in common.


title:
Creation of Quantum-Degenerate Gases of Ytterbium in a Compact
  2D-/3D-MOT Setup

abstract:
  We report on the first experimental setup based on a 2D-/3D-MOT scheme to
create both Bose-Einstein condensates and degenerate Fermi gases of several
ytterbium isotopes. Our setup does not require a Zeeman slower and offers the
flexibility to simultaneously produce ultracold samples of other atomic
species. Furthermore, the extraordinary optical access favors future
experiments in optical lattices. A 2D-MOT on the strong 1S0-1P1 transition
captures ytterbium directly from a dispenser of atoms and loads a 3D-MOT on the
narrow 1S0-3P1 intercombination transition. Subsequently, atoms are transferred
to a crossed optical dipole trap and cooled evaporatively to quantum
degeneracy.


title: Flux growth and physical properties of Mo3Sb7 single crystals

abstract:
  Millimeter sized single crystals of Mo3Sb7 are grown using the self-flux
technique and a thorough characterization of their structural, magnetic,
thermal and transport properties is reported. The structure parameters for the
high-temperature cubic phase and the low-temperature tetragonal phase were, for
the first time, determined with neutron single crystal diffraction. Both X-ray
powder diffraction and neutron single crystal diffraction at room temperature
confirmed that Mo3Sb7 crystallizes in Ir3Ge7-type cubic structure with space
group Im-3m. The cubic-tetragonal structure transition at 53K is verified by
the peak splitting of (4 0 0) reflection observed by X-ray single crystal
diffraction and the dramatic intensity change of (12 0 0) peak observed by
neutron single crystal diffraction. The structural transition is accompanied by
a sharp drop in magnetic susceptibility, electrical resistivity, and
thermopower while cooling. A weak lambda anomaly was also observed around 53K
in the temperature dependence of specific heat and the entropy change across
the transition is estimated to be 1.80J/molMoK. The temperature dependence of
magnetic susceptibility was measured up to 750K and it follows a Curie-Weiss
behavior above room temperature. Analysis of the low-temperature magnetic
susceptibility suggests a spin gap of 110K around 53K. A typical phonon thermal
conductivity was observed in the low temperature tetragonal phase. A glassy
phonon thermal conductivity above 53K suggests a structural instability in a
wide temperature range. Superconductivity was observed at 2.35K in the as-grown
crystals and the dimensionless specific heat jump was determined to be 1.49,
which is slightly larger than the BCS value of 1.43 for the weak-coupling
limit.


title: An Old Disk That Can Still Form a Planetary System

abstract:
  From the masses of planets orbiting our Sun, and relative elemental
abundances, it is estimated that at birth our Solar System required a minimum
disk mass of ~0.01 solar masses within ~100 AU of the star. The main
constituent, gaseous molecular hydrogen, does not emit from the disk mass
reservoir, so the most common measure of the disk mass is dust thermal emission
and lines of gaseous carbon monoxide. Carbon monoxide emission generally probes
the disk surface, while the conversion from dust emission to gas mass requires
knowledge of the grain properties and gas-to-dust mass ratio, which likely
differ from their interstellar values. Thus, mass estimates vary by orders of
magnitude, as exemplified by the relatively old (3--10 Myr) star TW Hya, with
estimates ranging from 0.0005 to 0.06 solar masses. Here we report the
detection the fundamental rotational transition of hydrogen deuteride, HD,
toward TW Hya. HD is a good tracer of disk gas because it follows the
distribution of molecular hydrogen and its emission is sensitive to the total
mass. The HD detection, combined with existing observations and detailed
models, implies a disk mass >0.05 solar masses, enough to form a planetary
system like our own.


title:
The photino sector and a confining potential in a supersymetric
  Lorentz-symmetry-violating model

abstract:
  We study the spectrum of the minimal supersymmetric extension of the
Carroll-Field-Jackiw model for Electrodynamics with a topological
Chern-Simons-like Lorentz-symmetry violating term. We identify a number of
independent background fermion condensates, work out the gaugino dispersion
relation and propose a photonic effective action to consider aspects of
confinement induced by the SUSY background fermion condensates, which also
appear to signal Lorentz-symmetry violation in the photino sector of the
action. Our calculations of the static potential are carried out within the
framework of the gauge-invariant but path-dependent variables formalism which
are alternative to the Wilson loop approach. Our results show that the
interaction energy contains a linear term leading to the confinement of static
probe charges.


title:
Interplanetary Nanodust Detection by the Solar Terrestrial Relations
  Observatory/WAVES Low Frequency Receiver

abstract:
  New measurements using radio and plasma-wave instruments in interplanetary
space have shown that nanometer-scale dust, or nanodust, is a significant
contributor to the total mass in interplanetary space. Better measurements of
nanodust will allow us to determine where it comes from and the extent to which
it interacts with the solar wind. When one of these nanodust grains impacts a
spacecraft, it creates an expanding plasma cloud, which perturbs the
photoelectron currents. This leads to a voltage pulse between the spacecraft
body and the antenna. Nanodust has a high charge/mass ratio, and therefore can
be accelerated by the interplanetary magnetic field to speeds up to the speed
of the solar wind: significantly faster than the Keplerian orbital speeds of
heavier dust. The amplitude of the signal induced by a dust grain grows much
more strongly with speed than with mass of the dust particle. As a result,
nanodust can produce a strong signal, despite their low mass. The WAVES
instruments on the twin Solar TErrestrial RElations Observatory spacecraft have
observed interplanetary nanodust particles since shortly after their launch in
2006. After describing a new and improved analysis of the last five years of
STEREO/WAVES Low Frequency Receiver data, a statistical survey of the nanodust
characteristics, namely the rise time of the pulse voltage and the flux of
nanodust, is presented. Agreement with previous measurements and interplanetary
dust models is shown. The temporal variations of the nanodust flux are also
discussed.


title: Phase diagram of the isotropic spin-3/2 model on the z=3 Bethe lattice

abstract:
  We study an SU(2) symmetric spin-3/2 model on the z=3 Bethe lattice using the
infinite Time Evolving Block Decimation (iTEBD) method. This model is shown to
exhibit a rich phase diagram. We compute the expectation values of several
order parameters which allow us to identify a ferromagnetic, a ferrimagnetic, a
anti-ferromagnetic as well as a dimerized phase. We calculate the entanglement
spectra from which we conclude the existence of a symmetry protected
topological phase that is characterized by S=1/2 edge spins. Details of the
iTEBD algorithm used for the simulations are included.


title: Radial Coordinates for Conformal Blocks

abstract:
  We develop the theory of conformal blocks in CFT_d expressing them as power
series with Gegenbauer polynomial coefficients. Such series have a clear
physical meaning when the conformal block is analyzed in radial quantization:
individual terms describe contributions of descendants of a given spin.
Convergence of these series can be optimized by a judicious choice of the
radial quantization origin. We argue that the best choice is to insert the
operators symmetrically. We analyze in detail the resulting "rho-series" and
show that it converges much more rapidly than for the commonly used variable z.
We discuss how these conformal block representations can be used in the
conformal bootstrap. In particular, we use them to derive analytically some
bootstrap bounds whose existence was previously found numerically.


title: Automatic structures for subsemigroups of Baumslag--Solitar semigroups

abstract:
  This paper studies automatic structures for subsemigroups of
Baumslag--Solitar semigroups (that is, semigroups presented by $\ < x,y \mid
(yx^m, x^ny)\ >$, where $m$ and $n$ are natural numbers). A geometric argument
(a rarity in the field of automatic semigroups) is used to show that if $m \gt
n$, all of the finitely generated subsemigroups of this semigroup are [right-]
automatic. If $m \lt n$, all of its finitely generated subsemigroups are
left-automatic. If $m = n$, there exist finitely generated subsemigroups that
are not automatic. An appendix discusses the implications of these results for
the theory of Malcev presentations. (A Malcev presentation is a special type of
presentation for semigroups embeddable into groups.)


abstract:
  Logarithmic operators and logarithmic conformal field theories are reviewed.
Prominent examples considered here include c=-2 and c=0 logarithmic conformal
field theories. c=0 logarithmic conformal field theories are especially
interesting since they describe some of the critical points of a variety of
longstanding problems involving a two dimensional quantum particle moving in a
spatially random potential, as well as critical two dimensional self avoiding
random walks and percolation. Lack of classification of logarithmic conformal
field theories remains a major impediment to progress towards finding complete
solutions to these problems.


title:
New theoretical method for calculating the radiative association cross
  section of a triatomic molecule: Application to N2-H-

abstract:
  We present a new theoretical method to treat the atom diatom radiative
association within a time independent approach. This method is an adaptation of
the driven equations method developed for photodissociation. The bound states
energies and wave functions of the molecule are calculated exactly and used to
propagate the overlap with the initial scattering wave function. In the second
part of this paper, this approach is applied to the radiative association of
the N2H- anion. The main features of the radiative association cross sections
are analysed and the magnitude of the calculated rate coefficient at 10 Kelvin
is used to discuss the existence of the N2H- in the interstellar medium which
could be used as a tracer of both N2 and H-.


title:
From Kleisli Categories to Commutative C*-algebras: Probabilistic
  Gelfand Duality

abstract:
  C*-algebras form rather general and rich mathematical structures that can be
studied with different morphisms (preserving multiplication, or not), and with
different properties (commutative, or not). These various options can be used
to incorporate various styles of computation (set-theoretic, probabilistic,
quantum) inside categories of C*-algebras. At first, this paper concentrates on
the commutative case and shows that there are functors from several Kleisli
categories, of monads that are relevant to model probabilistic computations, to
categories of C*-algebras. This yields a new probabilistic version of Gelfand
duality, involving the "Radon" monad on the category of compact Hausdorff
spaces. We then show that the state space functor from C*-algebras to
Eilenberg-Moore algebras of the Radon monad is full and faithful. This allows
us to obtain an appropriately commuting state-and-effect triangle for
C*-algebras.


title:
On the perodicity of the first Betti number of the semigroup rings under
  translations

abstract:
  Let k be a field of characteristic zero. Given an ordered 3-tuple of positive
integers a=(a,b,c) and for j in N, a family of sequences a_j = (j,a+j,a+b+j,
a+b+c+j), we consider the collection of monomial curves in A^{4} associated
with a_j. The Betti numbers of the Semigroup rings collection associated with
a_j are conjectured to be eventually periodic with period a+b+c by Herzog and
Srinivasan. Let p in N, in this paper, we prove that for a = (p(b+c),b, c) or a
= (a, b, p(a+b)) in the collection of defining ideals associated with a_j, for
large j the ideals are complete intersections if and only if (a + b + c)|j.
Moreover, the complete intersections are periodic with the conjectured period.


title:
Existence, Uniqueness and Removable Singularities for Nonlinear Partial
  Differential Equations in Geometry

abstract:
  This paper surveys some recent results on existence, uniqueness and removable
singularities for fully nonlinear differential equations on manifolds. The
discussion also treats restriction theorems and the strong Bellman principle.


title:
Solving Toda field theories and related algebraic and differential
  properties

abstract:
  Toda field theories are important integrable systems. They can be regarded as
constrained WZNW models, and this viewpoint helps to give their explicit
general solutions, especially when a Drinfeld-Sokolov gauge is used. The main
objective of this paper is to carry out this approach of solving the Toda field
theories for the classical Lie algebras. In this process, we discover and prove
some algebraic identities for principal minors of special matrices. The known
elegant solutions of Leznov fit in our scheme in the sense that they are the
general solutions to our conditions discovered in this solving process. To
prove this, we find and prove some differential identities for iterated
integrals. It can be said that altogether our paper gives complete mathematical
proofs for Leznov's solutions.


title: Termite-hill: From natural to artificial termites in sensor networks

abstract:
  Termites present a very good natural metaphor to evolutionary computation.
While each individuals computational power is small compared to more evolved
species, it is the power of their colonies that inspires communication
engineers. This paper presents a study of artificial termites in sensor
networks for the purpose of solving its routing problem. The behaviors of each
of the termites in their colony allow their simulation in a restricted
environment. The simulating behavior demonstrates how the termites make use of
an auto-catalytic behavior in order to collectively find a solution for a posed
problem in reasonable time. The derived algorithm termed Termite-hill
demonstrates the principle of termites behavior to routing problem solving in
the real applications of sensor networks. The performance of the algorithm was
tested on static and dynamic sink scenarios. The results as compared with other
routing algorithms and with varying network density show that Termite-hill is
scalable and improved on network energy consumption with a control over
best-effort-service.


title:
Hadron Collider Production of Massive Color-Octet Vector Bosons at
  Next-to-Leading Order

abstract:
  This paper completes the study of the next-to-leading order (NLO) QCD
corrections to massive color-octet vector boson production at the LHC and
Tevatron. The massive color-octet vector bosons are generically referred to as
colorons. Building on our previous calculation of quark-initiated coloron
production at NLO, we use the pinch technique to investigate coloron production
via gluon fusion. We demonstrate that this one-loop production amplitude is
finite, and find that its numerical contribution to coloron production is
typically four orders of magnitude smaller than the contribution from quark
annihilation. Coloron production via gluon fusion is therefore only relevant if
the colorons are (nearly) fermiophobic. We then present extensive plots and
tables of our full results for NLO coloron production at the Tevatron and the
LHC.


title: Automatic sorting of point pattern sets using Minkowski Functionals

abstract:
  Point pattern sets arise in many different areas of physical, biological, and
applied research, representing many random realizations of underlying pattern
formation mechanisms. These pattern sets can be heterogeneous with respect to
underlying spatial processes, which may not be visually distinguishable. This
heterogeneity can be elucidated by looking at statistical measures of the
patterns sets and using these measures to divide the pattern set into distinct
groups representing like spatial processes. We introduce here a numerical
procedure for sorting point pattern sets into spatially homogeneous groups
using Functional Principal Component Analysis (FPCA) applied to the
approximated Minkowski functionals of each pattern. We demonstrate that this
procedure correctly sorts pattern sets into similar groups both when the
patterns are drawn from similar processes and when the 2nd-order
characteristics of the pattern are identical. We highlight this routine for
distinguishing the molecular patterning of fluorescently labeled cell membrane
proteins, a subject of much interest in studies investigating complex spatial
signaling patterns involved in the human immune response.


title:
Exciton fine-structure splitting of telecom wavelength single quantum
  dots: statistics and external strain tuning

abstract:
  In a charge tunable device, we investigate the fine structure splitting of
neutral excitons in single long-wavelength (1.1\mu m < \lambda < 1.3 \mu m)
InGaAs quantum dots as a function of external uniaxial strain. Nominal fine
structure splittings between 16 and 136 \mu eV are measured and manipulated. We
observe varied response of the splitting to the external strain, including
positive and negative tuning slopes, different tuning ranges, and linear and
parabolic dependencies, indicating that these physical parameters depend
strongly on the unique microscopic structure of the individual quantum dot. To
better understand the experimental results, we apply a phenomenological model
describing the exciton polarization and fine-structure splitting under uniaxial
strain. The model predicts that, with an increased experimental strain tuning
range, the fine-structure can be effectively canceled for select telecom
wavelength dots using uniaxial strain. These results are promising for the
generation of on-demand entangled photon pairs at telecom wavelengths.


title:
Intrinsic energy of Lema\^itre-Tolman-Bondi models and cosmological
  implications

abstract:
  Recently, some Lema{\^{\i}}tre-Tolman-Bondi metrics have been considered as
models alternative to the dark energy within the
Friedmann-Lema{\^{\i}}tre-Robertson-Walker universes. The vanishing of the
intrinsic energy of these metrics is examined since such a vanishing, in the
present case and in general, could be interpreted as a necessary condition to
consider the possibility of the quantum creation of a metric. More
specifically, this vanishing is examined in the particular case where the
Lema{\^{\i}}tre-Tolman-Bondi metrics behave asymptotically like a
Friedmann-Lema{\^{\i}}tre-Robertson-Walker universe. Finally, we deal with a
particular model ruled out after being confronted with cosmic observations. In
a minimal agreement with this negative result, leaving aside an unstable case,
the value of the intrinsic energy of this particular model does not vanish and
becomes in fact minus infinite.


title: On characteristic integrals of Toda field theories

abstract:
  Characteristic integrals of Toda field theories associated to simple Lie
algebras are presented in the most explicit forms, both in terms of the
formulas and in terms of the proofs.


title:
Two-Qubit Rational-Valued Entanglement-Boundary Probability Densities
  and a Fisher Information Equality Conjecture

abstract:
  We consider a pair of one-parameter (alpha) families of generalized two-qubit
determinantal Hilbert-Schmidt probability distributions, p_{alpha}(|rho^{PT}|)
and q_{alpha}(|rho|), where rho is a 4 x 4 density matrix, rho^{PT}, its
partial transpose, with |rho^{PT}| \in [-1/16,1/256] and |rho| \in [0, 1/256].
The Dyson-index-like (random matrix) parameter alpha is 1/2 for the
9-dimensional generic two-rebit systems, 1 for the 15-dimensional generic
two-qubit systems,... Numerical (moment-based
probability-distribution-reconstruction) analyses suggest the conjecture that
the Fisher information--a measure over alpha--is identical for the two distinct
families. Further, we study the values of p_{alpha}(0), the probability
densities at the separability-entanglement boundary, with evidence strongly
indicating that p_2(0) =7425/34 and p_3(0)= 7696/69. Despite extensive results
of such a nature, we have not yet succeeded--in contrast with the corresponding
rational-valued separability probabilities (arXiv.org:1301.6617)--in generating
an underlying, explanatory ("concise") formula for p_{\alpha}(0), even though
the corresponding denominators of both sets of rational-valued results are
closely related, having almost identical (small) prime factors. The first
derivatives p_{alpha}^{'}(0) are positive for alpha = 1/2 and 1, but negative
for alpha > 1.


title: Spectroscopy of Solar Prominences Simultaneously from Space and Ground

abstract:
  We present a comprehensive set of spectral data from two quiescent solar
prominences observed in parallel from space and ground: with the VTT,
simultaneous two-dimensional imaging of H-beta 4862 and Ca II 8542 yields a
constant ratio, indicating small spatial pressure variations over the
prominences. With the Gregory, simultaneous spectra of Ca II 8542 and He I
10830 were taken, their widths yielding 8000< T_kin< 9000 K and v_nth<8 km/s.
The intensity ratio of the helium triplet components gives an optical thickness
of tau < 1.0 for the fainter and tau < 2.0 for the brighter prominence. The
tau_0 values allow to deduce the source function for the central line
intensities and thus the relative population of the helium 3S and 3P levels
with a mean excitation temperature T_ex = 3750 K.
  With SUMER, we sequentially observed 6 spectral windows containing higher
Lyman lines, 'cool' emission lines from neutrals and singly charged atoms, as
well as 'hot' emission lines from ions like O IV, O V, N V, S V and S VI. The
EUV lines show pronounced maxima in the main prominence body as well as
'side-locations' where the 'hot' lines are enhanced with respect to the 'cool'
lines. The line radiance of 'hot' lines blue-wards of the Lyman series limit
(lambda<912 A) appear reduced in the main prominence body. This absorption is
also visible in TRACE images of Fe IX/X 171 as fine dark structure which covers
only parts of the main ('cool') prominence body.
  The Lyman lines show a smooth decrease of line widths and radiance with
increasing upper level k = 5 through 19. For k= 5 through 8 the level
population follows a Boltzmann distribution with T_ex >6 *10^4 K; higher levels
k > 8 appear more and more overpopulated. The larger widths of the Lyman lines
require high non-thermal broadening close to that of 'hot' EUV lines. In
contrast, the He II emission is more related to the 'cool' lines.


title:
Stationary bound states of spin-half particles in the Kerr and
  Kerr-Newman gravitational fields

abstract:
  We prove the possibility of existence of stationary bound states of
stationary bound states of spin-half probe particles for the Kerr and
Kerr-Newman gravitational fields using Chandrasekhar's Hamiltonian. If the
Hilbert condition is satisfied, g_{00}>0, bound states of Dirac particles with
a real discrete energy spectrum can exist both for particles outside the
surface of the outer ergosphere of the Kerr and Kerr-Newman fields, and for
particles under the surface of the inner ergosphere. In this case, the surfaces
of the external and internal ergospheres play the role of infinitely high
potential barriers. Spin-half quantum-mechanical particles cannot cross the
ergosphere surfaces of the Kerr and Kerr-Newman fields. Based on the results of
this study, we can assume that there exists a new type of rotating collapsars,
for which the Hawking radiation is absent. The results of this study can lead
to a revision of some concepts of the standard cosmological model related to
the evolution of the universe and interaction of rotating collapsars with
surrounding matter.


title: Geometry of Bounded Frechet Manifolds

abstract:
  In this paper we develop the geometry of bounded Fr\'echet manifolds. We
prove that a bounded Fr\'echet tangent bundle admits a vector bundle structure.
But the second order tangent bundle $T^2M$ of a bounded Fr\'echet manifold $M$,
becomes a vector bundle over $M$ if and only if $M$ is endowed with a linear
connection. As an application, we prove the existence and uniqueness of the
integral curve of a vector field on $M$.


title: Palindromic width of free nilpotent groups

abstract:
  In this paper we consider the palindromic width of free nilpotent groups. In
particular, we prove that the palindromic width of a finitely generated free
nilpotent group is finite. We also prove that the palindromic width of a free
abelian-by-nilpotent group is finite.


title: Universality and critical behavior in the chiral two-matrix model

abstract:
  We study the chiral two-matrix model with polynomial potential functions $V$
and $W$, which was introduced by Akemann, Damgaard, Osborn and Splittorff. We
show that the squared singular values of each of the individual matrices in
this model form a determinantal point process with correlation kernel
determined by a matrix-valued Riemann-Hilbert problem. The size of the
Riemann-Hilbert matrix depends on the degree of the potential function $W$ (or
$V$ respectively). In this way we obtain the chiral analogue of a result of
Kuijlaars-McLaughlin for the non-chiral two-matrix model. The Gaussian case
corresponds to $V,W$ being linear. For the case where $W(y)=y^2/2+\alpha y$ is
quadratic, we derive the large $n$-asymptotics of the Riemann-Hilbert problem
by means of the Deift-Zhou steepest descent method. This proves universality in
this case. An important ingredient in the analysis is a third-order
differential equation. Finally we show that if also $V(x)=x$ is linear, then a
multi-critical limit of the kernel exists which is described by a $4\times 4$
matrix-valued Riemann-Hilbert problem associated to the Painlev\'e II equation
$q"(x) = xq(x)+2q^3(x)-\nu-1/2$. In this way we obtain the chiral analogue of a
recent result by Duits and the second author.


title: Intrinsic construction of invariant functions on simple Lie algebras

abstract:
  An algorithm for constructing primitive adjoint-invariant functions on a
complex simple Lie algebra is presented. The construction is intrinsic in the
sense that it does not resort to any representation. A primitive invariant
function on the whole Lie algebra is obtained by lifting a coordinate function
on a Kostant slice of the Lie algebra. Such an intrinsic construction of
invariant functions is most useful for the bigger exceptional Lie algebras such
as the E's. The Maple implementation of this algorithm is outlined at the end
and will be applied to these exceptional Lie algebras in a future work.


title: Tropicalization of classical moduli spaces

abstract:
  The image of the complement of a hyperplane arrangement under a monomial map
can be tropicalized combinatorially using matroid theory. We apply this to
classical moduli spaces that are associated with complex reflection
arrangements. Starting from modular curves, we visit the Segre cubic, the Igusa
quartic, and moduli of marked del Pezzo surfaces of degrees 2 and 3. Our
primary example is the Burkhardt quartic, whose tropicalization is a
3-dimensional fan in 39-dimensional space. This effectuates a synthesis of
concrete and abstract approaches to tropical moduli of genus 2 curves.


title:
Microwave conductance in random waveguides in the crossover to Anderson
  localization and single parameter scaling

abstract:
  The nature of transport of electrons and classical waves in disordered
systems depends upon the proximity to the Anderson localization transition
between freely diffusing and localized waves. The suppression of average
transport and the enhancement of relative fluctuations in conductance in
one-dimensional samples with lengths greatly exceeding the localization length,
$L\gg \xi$, are related in the single parameter scaling (SPS) theory of
localization. However, the difficulty of producing an ensemble of statistically
equivalent samples in which the electron wavefunction is temporally coherent
has so-far precluded the experimental demonstration of SPS. Here we demonstrate
SPS in random multichannel systems for the transmittance $T$ of microwave
radiation, which is the analogue of the dimensionless conductance. We show that
for $L\sim4\xi$ a single eigenvalue of the transmission matrix (TM) dominates
transmission and the distribution of the $\ln T$ is Gaussian with a variance
equal to the average of $-\ln T$, as conjectured by SPS. For samples in the
crossover to localization, $L\sim\xi$, we find a one-sided distribution for
$\ln T$. This anomalous distribution is explained in terms of a charge model
for the eigenvalues of the transmission matrix $\tau$ in which the Coulomb
interaction between charges mimics the repulsion between the eigenvalues of
transmission matrix. We show in the localization limit that the joint
distribution of $T$ and the effective number of transmission eigenvalues
determines the probability distributions of intensity and total transmission
for a single incident channel.


title:
Utility maximisation and utility indifference price for exponential
  semi-martingale models with random factor

abstract:
  We consider utility maximization problem for semi-martingale models depending
on a random factor $\xi$. We reduce initial maximization problem to the
conditional one, given $\xi=u$, which we solve using dual approach. For HARA
utilities we consider information quantities like Kullback-Leibler information
and Hellinger integrals, and corresponding information processes. As a
particular case we study exponential Levy models depending on random factor. In
that case the information processes are deterministic and this fact simplify
very much indifference price calculus. Then we give the equations for
indifference prices. We show that indifference price for seller and minus
indifference price for buyer are risk measures. Finally, we apply the results
to Geometric Brownian motion case. Using identity in law technique we give the
explicit expression for information quantities. Then, the previous formulas for
indifference price can be applied.


title: Killing Symmetries in $\mathcal{H}$-Spaces with $\Lambda$

abstract:
  All Killing symmetries in complex $\mathcal{H}$-spaces with $\Lambda$ in
terms of the Pleba\'nski - Robinson - Finley coordinate system are found. All
$\mathcal{H}$-metrics with $\Lambda$ admitting a null Killing vector are
explicitly given. It is shown that the problem of non-null Killing vector
reduces to looking for solution of the Boyer - Finley - Pleba\'nski (Toda
field) equation


title: Grid Minors in Damaged Grids

abstract:
  We prove upper and lower bounds on the size of the largest square grid graph
that is a subgraph, minor, or shallow minor of a graph in the form of a larger
square grid from which a specified number of vertices have been deleted. Our
bounds are tight to within constant factors. We also provide less-tight bounds
on analogous problems for higher-dimensional grids.


title:
Observation of Transient Momentum-Space Interference During Scattering
  of a Condensate From an Optical Barrier

abstract:
  Scattering theory traditionally deals with the asymptotic behaviour of a
system far removed from the actual scattering event. Here we present an
experimental study of the one-dimensional scattering of a non-interacting
condensate of 87-Rb atoms from a potential barrier in the non-asymptotic
regime, for which the collision dynamics are still ongoing. We show that for
near-transparent barriers, there are two distinct transient scattering effects
that arise and dramatically change the momentum distribution during the
collision: a deceleration of wavepacket components in mid-collision, and an
interference between incident and transmitted portions of the wavepacket. Both
effects lead to the re-distribution of momenta giving rise to a rich
interference pattern that can be used to perform reconstruction of the
single-particle phase profile.


title:
Contributions to the event-by-event charge asymmetry dependence for the
  elliptic flow of pi^{+} and pi^{-} in heavy-ion collisions

abstract:
  We discuss various contributions to the event-by-event charge-asymmetry
dependence of $\pi^{+}$ and $\pi^{-}$ elliptic flow, recently measured by the
STAR Collaboration at RHIC. It is shown that under general assumptions, the
difference between $v_2^+$ and $v_2^-$ at a given fluctuating value of an
asymmetry parameter, $A$, is a linear function of $A$, as observed in the
preliminary data. We discuss two mechanisms that are qualitatively consistent
with the experimental data and result in a signal of the correct order of
magnitude. Our subsequent hydrodynamic calculations, assuming local charge
conservation at freeze-out, yield a qualitative and partial quantitative
understanding of the observed signal, so offering a detailed test of the
hydrodynamic model in heavy-ion collisions.


title: Observing the Onset of Effective Mass

abstract:
  The response of a particle in a periodic potential to an applied force is
commonly described by an effective mass which accounts for the detailed
interaction between the particle and the surrounding potential. Using a
Bose-Einstein condensate of 87-Rb atoms initially in the ground band of an
optical lattice, we experimentally show that the initial response of a particle
to an applied force is in fact characterized by the bare mass. Subsequently,
the particle response undergoes rapid oscillations and only over timescales
long compared to that of the interband dynamics is the effective mass observed
to be an appropriate description.


title: Color Breaking in the Early Universe

abstract:
  We explore the possibility that color symmetry SU(3) was not an exact
symmetry at all times in the early universe, using minimal extensions of the
standard model that contain a color triplet scalar field and perhaps other
fields. We show that, for a range of temperatures, there can exist a phase in
which the free energy is minimized when the color triplet scalar has a
non-vanishing vacuum expectation value, spontaneously breaking color. At very
high temperatures and at lower temperatures color symmetry is restored. The
breaking of color in this phase is accompanied by the spontaneous breaking of
B-L if the color triplet scalar Yukawa couples to quarks and/or leptons. We
discuss the requirements on the minimal extensions needed for consistency of
this scenario with present collider bounds on new colored scalar particles.


title:
The metals-to-dust ratio to very low metallicities using GRB and QSO
  absorbers; extremely rapid dust formation

abstract:
  Among the key parameters defining the ISM of galaxies is the fraction of the
metals that are locked up in dust: the metals-to-dust ratio. This ratio bears
not only on the ISM and its evolution, but particularly on the origin of cosmic
dust. We combine extinction and abundance data from GRB afterglows, from QSO
absorbers, as well as from galaxy-lensed QSOs, to determine the metals-to-dust
ratios for lines-of-sight through a wide diversity of galaxies from blue, dwarf
starbursts to massive ellipticals, across a vast range in redshift z=0.1-6.3,
and nearly three orders of magnitude in column density and metal abundance. We
thus determine the metals-to-dust ratio in a unique way, providing direct
determinations of in situ gas and dust columns without recourse to assumptions
with large uncertainties. We find that the metals-to-dust ratios in these
systems are surprisingly close to the value for the local group (10^{21.3} cm-2
A_V mag-1), with a mean value of 10^{21.2} cm-2 A_V mag-1 and a standard
deviation of 0.3 dex. There is no evidence of deviation from this mean ratio as
a function of metallicity, even down to our lowest metallicity of 0.01 Z/Z_sun.
The lack of any obvious dependence of the metals-to-dust ratio on either column
density, galaxy type or age, redshift, or metallicity indicates a close
correspondence between the formation of the metals and the formation of dust.
Any delay between the formation of metals and dust must be shorter than the
typical metal-enrichment times of these galaxies. Formation of the bulk of the
dust in low mass stars is therefore ruled out by these data at any cosmic
epoch. Furthermore, dust destruction must not dominate over formation/growth in
virtually any galaxy environment. The correlation between metals and dust is a
natural consequence of the formation of the bulk of dust in SNe [Abridged].


title: Implications of the Higgs Boson and the LHC for the MSSM

abstract:
  These lectures were presented at the TASI 2012 summer school to a mixture of
graduate students in particle theory and cosmology. They serve as an elementary
introduction to the Minimal Supersymmetric Standard Model (MSSM) and discuss
the implications of a 125 GeV Higgs boson for this theory. Some familiarity
with the Standard Model is assumed.


title:
Quantum dynamics of an optomechanical system in the presence of
  Kerr-down conversion nonlinearity

abstract:
  We study theoretically nonlinear effects arising from the presence of a
Kerr-down conversion nonlinear crystal inside an optomechanical cavity. For
this system we investigate the influences of the two nonlinearities, i.e., the
Kerr nonlinearity and the parametric gain, on the dynamics of the oscillating
mirror, the intensity and the squeezing spectra of the transmitted field, and
the steady-state mirror-field entanglement. We show that in comparison with a
bare optomechanical cavity, the combination of the cavity energy shift due to
the Kerr nonlinearity and increase in the intracavity photon number due to the
gain medium can increase the normal mode splitting in the displacement spectrum
of the oscillating mirror and reduce its effective temperature. Our work
demonstrates that both the Kerr nonlinearity and down conversion process
increase the degree of squeezing in the transmitted field. Moreover, we find
that in the system under consideration the degree of entanglement between the
mechanical and optical modes decreases considerably because of the intracavity
photon number reduction in the presence of the Kerr medium.


title: Recursive Sparse Recovery in Large but Structured Noise - Part 2

abstract:
  We study the problem of recursively recovering a time sequence of sparse
vectors, St, from measurements Mt := St + Lt that are corrupted by structured
noise Lt which is dense and can have large magnitude. The structure that we
require is that Lt should lie in a low dimensional subspace that is either
fixed or changes "slowly enough"; and the eigenvalues of its covariance matrix
are "clustered". We do not assume any model on the sequence of sparse vectors.
Their support sets and their nonzero element values may be either independent
or correlated over time (usually in many applications they are correlated). The
only thing required is that there be some support change every so often. We
introduce a novel solution approach called Recursive Projected Compressive
Sensing with cluster-PCA (ReProCS-cPCA) that addresses some of the limitations
of earlier work. Under mild assumptions, we show that, with high probability,
ReProCS-cPCA can exactly recover the support set of St at all times; and the
reconstruction errors of both St and Lt are upper bounded by a time-invariant
and small value.


title:
Temperature dependent effective potential method for accurate free
  energy calculations of solids

abstract:
  We have developed a thorough and accurate method of determining anharmonic
free energies, the temperature dependent effective potential technique (TDEP).
It is based on \emph{ab initio} molecular dynamics followed by a mapping onto a
model Hamiltonian that describes the lattice dynamics. The formalism and the
numerical aspects of the technique are described in details. A number of
practical examples are given, and results are presented, which confirm the
usefulness of TDEP within \emph{ab initio} and classical molecular dynamics
frameworks. In particular, we examine from first-principles the behavior of
force constants upon the dynamical stabilization of body centered phase of Zr,
and show that they become more localized. We also calculate phase diagram for
$^4$He modeled with the Aziz \emph{et al.} potential and obtain results which
are in favorable agreement both with respect to experiment and established
techniques.


title:
Equivariant Poincar\'e-Alexander-Lefschetz duality and the
  Cohen-Macaulay property

abstract:
  We prove a Poincare-Alexander-Lefschetz duality theorem for rational
torus-equivariant cohomology and rational homology manifolds. We allow
non-compact and non-orientable spaces. We use this to deduce certain short
exact sequences in equivariant cohomology, originally due to Duflot in the
differentiable case, from similar, but more general short exact sequences in
equivariant homology. A crucial role is played by the Cohen-Macaulayness of
relative equivariant cohomology modules arising from the orbit filtration.


title: Kepler Photometry of Four Radio-Loud AGN in 2010-2012

abstract:
  We have used Kepler photometry to characterize variability in four radio-loud
active galactic nuclei (three quasars and one object tentatively identified as
a Seyfert 1.5 galaxy) on timescales from minutes to months, comparable to the
light crossing time of the accretion disk around the central supermassive black
hole or the base of the relativistic jet. Kepler's almost continuous
observations provide much better temporal coverage than is possible from
ground-based observations. We report the first such data analyzed for quasars.
We have constructed power spectral densities using 8 Kepler quarters of
long-cadence (30-minute) data for three AGN, 6 quarters for one AGN and 2
quarters of short-cadence (1-minute) data for all four AGN. On timescales
longer than about 0.2-0.6 day, we find red noise with mean power-law slopes
ranging from -1.8 to -1.2, consistent with the variability originating in
turbulence either behind a shock or within an accretion disk. Each AGN has a
range of red noise slopes which vary slightly by month and quarter of
observation. No quasi-periodic oscillations of astrophysical origin were
detected. We detected several days-long flares when brightness increased by 3%
- 7% in two objects. No flares on timescales of minutes to hours were detected.
Our observations imply that the duty cycle for enhanced activity in these
radio-loud AGN is small. These well-sampled AGN light curves provide an impetus
to develop more detailed models of turbulence in jets and instabilities in
accretion disks.


title: Chromatic polynomials of graphs from Kac-Moody algebras

abstract:
  We give a new interpretation of the chromatic polynomial of a simple graph G
in terms of the Kac-Moody Lie algebra with Dynkin diagram G. We show that the
chromatic polynomial is essentially the q-Kostant partition function of this
Lie algebra evaluated on the sum of the simple roots. Applying the Peterson
recurrence formula for root multiplicities, we obtain a new realization of the
chromatic polynomial as a weighted sum of paths in the bond lattice of G.


title: Suppression of Magnetic Phase Separation in Epitaxial SrCoOx Films

abstract:
  Using pulsed laser deposition and a unique fast quenching method, we have
prepared SrCoOx epitaxial films on SiTiO3 substrates. As electrochemical
oxidation increases the oxygen content from x = 2.75 to 3.0, the films tend to
favor the discrete magnetic phases seen in bulk samples for the homologous
series SrCoO(3-n/8) (n = 0, 1, 2). Unlike bulk samples, 200nm thick films
remain single phase throughout the oxidation cycle. 300 nm films can show two
simultaneous phases during deoxidation. These results are attributed to finite
thickness effects and imply the formation of ordered regions larger than
approximately 300 nm.


title:
The Higgs Singlet extension parameter space in the light of the LHC
  discovery

abstract:
  In this note we propose an overview on the current theoretical and
experimental limits on a Higgs singlet extension of the Standard Model. We
assume that the Boson which has recently been measured by the LHC experiments
is the lightest Higgs boson of such model, while for the second Higgs Boson we
consider a mass range of 600 GeV to 1 TeV, i.e. outside the range of the direct
searches presented so far. In this light, we study the impact of perturbative
unitarity limits, Renormalisation Group Equations analysis and experimental
constraints (Electro-Weak Precision Tests, measurements of the light Higgs
coupling at the Large Hadron Collider). We show that, in the case of no
additional hidden sector contributions, the largest constraints for higher
Higgs masses stem from the assumption of perturbativity as well as vacuum
stability for scales on the order of the SM metastability scale, and that the
allowed mixing range is severely restricted. We discuss implications for
current LHC searches in the singlet extension, especially the expected
suppression factors for SM-like decays of the heavy Higgs. We present these
results in terms of a global scaling factor as well as the total width of the
new scalar.


title: Local Spin Susceptibilities of Low-Dimensional Electron Systems

abstract:
  We investigate, assess, and suggest possibilities for a measurement of the
local spin susceptibility of a conducting low-dimensional electron system. The
basic setup of the experiment we envisage is a source-probe one. Locally
induced spin density (e.g. by a magnetized atomic force microscope tip) extends
in the medium according to its spin susceptibility. The induced magnetization
can be detected as a dipolar magnetic field, for instance, by an
ultra-sensitive nitrogen-vacancy center based detector, from which the spatial
structure of the spin susceptibility can be deduced. We find that
one-dimensional systems, such as semiconducting nanowires or carbon nanotubes,
are expected to yield a measurable signal. The signal in a two-dimensional
electron gas is weaker, though materials with high enough $g$-factor (such as
InGaAs) seem promising for successful measurements.


title: An Equivalence between the Lasso and Support Vector Machines

abstract:
  We investigate the relation of two fundamental tools in machine learning and
signal processing, that is the support vector machine (SVM) for classification,
and the Lasso technique used in regression. We show that the resulting
optimization problems are equivalent, in the following sense. Given any
instance of an $\ell_2$-loss soft-margin (or hard-margin) SVM, we construct a
Lasso instance having the same optimal solutions, and vice versa.
  As a consequence, many existing optimization algorithms for both SVMs and
Lasso can also be applied to the respective other problem instances. Also, the
equivalence allows for many known theoretical insights for SVM and Lasso to be
translated between the two settings. One such implication gives a simple
kernelized version of the Lasso, analogous to the kernels used in the SVM
setting. Another consequence is that the sparsity of a Lasso solution is equal
to the number of support vectors for the corresponding SVM instance, and that
one can use screening rules to prune the set of support vectors. Furthermore,
we can relate sublinear time algorithms for the two problems, and give a new
such algorithm variant for the Lasso. We also study the regularization paths
for both methods.


title:
Arhaeoastronomical analysis of Levinsadovka sacrificial complex (South
  Russia)

abstract:
  The article presents research data using arhaeoastronomical methods of
Levinsadovka settlement sacrificial complex in Northern Black Sea coast. In
this work, new method of accounting terrain elevations using topographic maps
was developed in arhaeoastronomical studies. Calculations of azimuths of the
sun and moon rise and set in the astronomically significant moments of the year
were made and astronomical regularities in the organization of the sacrificial
complex identified. Related to the moon directions, as the most dedicated,
identified. Revealed that the stone tools and fragments, used as sacrifices,
mark the direction to the northern minor standstill moonrise. A similar
situation was found on two archaeological sites: in Bezymennoye II settlement
South sanctuary and in Pustynka settlement religious building. Drawing on
ethnographic and folklore data, it is concluded about semiotic connection of
stone tools, found in these religious constructions, with the "thunderstones"
and meteorites.ut semiotic connection of stone tools, found in these religious
constructions, with the "thunderstones" and meteorites.


title:
Quantum spin liquids in the absence of spin-rotation symmetry:
  application to Herbertsmithite

abstract:
  It has been suggested that the nearest-neighbour (NN) antiferromagnetic
Heisenberg (HAF) model on the Kagome lattice may be a good starting point to
understand the quantum spin-liquid (QSL) behaviour discovered in
Herbertsmithite. We investigate possible QSL phases in the presence of
experimentally relevant spin-rotation symmetry-breaking perturbations such as
Dzyaloshinskii-Moriya and Ising interactions, as well as second-neighbour
antiferromagnetic Heisenberg interactions. We use the projective symmetry group
analysis within the slave-fermion framework of QSL phases and systematically
classify possible QSLs in the presence of these perturbations. The dynamical
spin-structure factor for relevant QSLs is computed and their effects are
studied. Our calculations reveal dispersive features in the spin structure
factor embedded in a generally diffuse background due to the existence of
fractionalized S=1/2 excitations called spinons. For two of the previously
proposed $Z_2$ states, the dispersive features are almost absent, and diffuse
scattering dominates over a large energy window throughout the Brillouin zone.
This resembles the structure factor observed in recent inelastic neutron
scattering experiments on singlet crystals of Herbertsmithite. Furthermore, one
of the $Z_2$ states with the spin structure factor with mostly diffuse
scattering is gapped, and it may be adiabatically connected to the gapped QSL
state observed in recent DMRG calculations for the NN HAF. The above
perturbations are found to enhance the diffuse nature of the spin structure
factor and reduce the momentum dependencies of the spin gap. We also calculate
the electron spin resonance absorption spectra that further characterize the
role of spin-rotation symmetry breaking perturbations, and can shed more light
into the nature of the ground state in Herbertsmithite.


title: Chemical-potential route for multicomponent fluids

abstract:
  The chemical potentials of multicomponent fluids are derived in terms of the
pair correlation functions for arbitrary number of components, interaction
potentials, and dimensionality. The formally exact result is particularized to
hard-sphere mixtures with zero or positive nonadditivity. As a simple
application, the chemical potentials of three-dimensional additive hard-sphere
mixtures are derived from the Percus-Yevick theory and the associated equation
of state is obtained. This Percus-Yevick chemical-route equation of state is
shown to be more accurate than the virial equation of state. An interpolation
between the chemical-potential and compressibility routes exhibits a better
performance than the well-known Boubl\'ik-Mansoori-Carnahan-Starling-Leland
equation of state.


title:
Digitally synthesized beat frequency multiplexing for sub-millisecond
  fluorescence microscopy

abstract:
  Fluorescence imaging is the most widely used method for unveiling the
molecular composition of biological specimens. However, the weak optical
emission of fluorescent probes and the tradeoff between imaging speed and
sensitivity is problematic for acquiring blur-free images of fast phenomena,
such as sub-millisecond biochemical dynamics in live cells and tissues, and
cells flowing at high speed. We report a solution that achieves real-time pixel
readout rates one order of magnitude faster than a modern electron multiplier
charge coupled device (EMCCD) - the gold standard in high-speed fluorescence
imaging technology. Deemed fluorescence imaging using
radiofrequency-multiplexed excitation (FIRE), this approach maps the image into
the radiofrequency spectrum using the beating of digitally synthesized optical
fields. We demonstrate diffraction-limited confocal fluorescence imaging of
stationary cells at a frame rate of 4.4 kHz, as well as fluorescence microscopy
in flow at a throughput of approximately 50,000 cells per second.


title: Massive non-planar two-loop four-point integrals with SecDec 2.1

abstract:
  We present numerical results for massive non-planar two-loop box integrals
entering heavy quark pair production at NNLO, some of which are not known
analytically yet. The results have been obtained with the program SecDec 2.1,
based on sector decomposition and contour deformation, in combination with new
types of transformations. Among the new features of version 2.1 is also the
possibility to evaluate contracted tensor integrals, with no limitation on the
rank.


title:
Communication: Virial coefficients and demixing in highly asymmetric
  binary additive hard-sphere mixtures

abstract:
  The problem of demixing in a binary fluid mixture of highly asymmetric
additive hard spheres is revisited. A comparison is presented between the
results derived previously using truncated virial expansions for three finite
size ratios with those that one obtains with the same approach in the extreme
case in which one of the components consists of point particles. Since this
latter system is known not to exhibit fluid-fluid segregation, the similarity
observed for the behavior of the critical constants arising in the truncated
series in all instances, while not being conclusive, may cast serious doubts as
to the actual existence of a demixing fluid-fluid transition in disparate-sized
binary additive hard-sphere mixtures.


title: Diagram vectors and Tight Frame Scaling in Finite Dimensions

abstract:
  We consider frames in a finite-dimensional Hilbert space Hn where frames are
exactly the spanning sets of the vector space. The diagram vector of a vector
in R2 was previously defined using polar coordinates and was used to
characterize tight frames in R2 in a geometric fashion. Reformulating the
definition of a diagram vector in R2 we provide a natural extension of this
notion to Rn and Cn. Using the diagram vectors we give a characterization of
tight frames in Rn or Cn. Further we provide a characterization of when a
unit-norm frame in Rn or Cn can be scaled to a tight frame. This classification
allows us to determine all scaling coefficients that make a unit-norm frame
into a tight frame.


title:
Influence of secondary decay on odd-even staggering of fragment cross
  sections

abstract:
  Odd-Even Staggering (OES) appears in many areas of nuclear physics, and is
generally associated with the pairing term in the nuclear binding energy. To
explore this effect, we use the Improved Statistical Multifragmentation Model
to populate an ensemble of hot primary fragments, which are then de-excited
using the Weisskopf-Ewing statistical emission formalism. The yields are then
compared to experimental data. Our results show that, before secondary decay,
OES appears only in the yields of even mass fragments and not in the yields of
odd mass fragments. De-excitation of the hot fragments must be taken into
account to describe the data, suggesting that the OES in fragment yields is a
useful criterion for validating or adjusting theoretical de-excitation models.


title: Word Values in p-Adic and Adelic Groups

abstract: We study the sets of values of words in p-adic and adelic groups.


title:
Lipschitz connectivity and filling invariants in solvable groups and
  buildings

abstract:
  We give some new methods, based on Lipschitz extension theorems, for bounding
filling invariants of subsets of nonpositively curved spaces. We apply our
methods to find sharp bounds on higher-order Dehn functions of Sol_{2n+1},
horospheres in euclidean buildings, Hilbert modular groups, and certain
S-arithmetic groups.


title: Maximum Robustness and Surgery of Frames in finite dimensions

abstract:
  We consider frames in a finite-dimensional Hilbert space Hn where frames are
exactly the spanning sets of the vector space. We present a method to determine
the maximum robustness of a frame. We present results on tight subframes and
surgery of frames. We also answer the question of when length surgery resulting
in a tight frame set for Hn is possible.


title: The landscape of two-proton radioactivity

abstract:
  Ground-state two-proton (2p) radioactivity is a decay mode found in isotopes
of elements with even atomic numbers located beyond the two-proton drip line.
So far, this exotic process has been experimentally observed in a few light and
medium-mass nuclides with Z less than or equal to 30. In this study, using
state-of-the-art nuclear density functional theory, we globally analyze 2p
radioactivity and for the first time identify 2p decay candidates in elements
heavier than strontium. We predict a few cases where the competition between 2p
emission and alpha decay may be observed. In nuclei above lead, the alpha decay
mode is found to be dominating and no measurable candidates for the 2p
radioactivity are expected.


title:
The reduced Hartree-Fock model for short-range quantum crystals with
  defects

abstract:
  In this article, we consider quantum crystals with defects in the reduced
Hartree-Fock framework. The nuclei are supposed to be classical particles
arranged around a reference periodic configuration. The perturbation is assumed
to be small in amplitude, but need not be localized in a specific region of
space or have any spatial invariance. Assuming Yukawa interactions, we prove
the existence of an electronic ground state, solution of the self-consistent
field equation. Next, by studying precisely the decay properties of this
solution for local defects, we are able to expand the density of states of the
nonlinear Hamiltonian of a system with a random perturbation of
Anderson-Bernoulli type, in the limit of low concentration of defects. One
important step in the proof of our results is the analysis of the dielectric
response of the crystal to an effective charge perturbation.


title:
Maximal Regularity for Evolution Equations Governed by Non-Autonomous
  Forms

abstract:
  \begin{abstract}\label{abstract} We consider a non-autonomous evolutionary
problem \[ \dot{u} (t)+\A(t)u(t)=f(t), \quad u(0)=u_0 \] where the operator
$\A(t):V\to V^\prime$ is associated with a form $\fra(t,.,.):V\times V \to \R$
and $u_0\in V$. Our main concern is to prove well-posedness with maximal
regularity which means the following. Given a Hilbert space $H$ such that $V$
is continuously and densely embedded into $H$ and given $f\in L^2(0,T;H)$ we
are interested in solutions $u \in H^1(0,T;H)\cap L^2(0,T;V)$. We do prove
well-posedness in this sense whenever the form is piecewise
Lipschitz-continuous and symmetric. Moreover, we show that each solution is in
$C([0,T];V)$. We apply the results to non-autonomous Robin-boundary conditions
and also use maximal regularity to solve a quasilinear problem.


title:
Invariance of Convex Sets for Non-autonomous Evolution Equations
  Governed by Forms

abstract:
  We consider a non-autonomous form $\fra:[0,T]\times V\times V \to \C$ where
$V$ is a Hilbert space which is densely and continuously embedded in another
Hilbert space $H$. Denote by $\A(t) \in \L(V,V')$ the associated operator.
Given $f \in L^2(0,T, V')$, one knows that for each $u_0 \in H$ there is a
unique solution $u\in H^1(0,T;V')\cap L^2(0,T;V)$ of $$\dot u(t) + \A(t) u(t) =
f(t), \, \, u(0) = u_0.$$ %\begin{align*} %&\dot u(t) + \A(t)u(t)= f(t)\ %&
u(0)=u_0. %\end{align*} This result by J. L. Lions is well-known. The aim of
this article is to find a criterion for the invariance of a closed convex
subset $\Conv$ of $H$; i.e.\ we give a criterion on the form which implies that
$u(t)\in \Conv$ for all $t\in[0,T]$ whenever $u_0\in\Conv$. In the autonomous
case for $f = 0$, the criterion is known and even equivalent to invariance by a
result proved in \cite{Ouh96} (see also \cite{Ouh05}). We give applications to
positivity and comparison of solutions to heat equations with non-autonomous
Robin boundary conditions. We also prove positivity of the solution to a
quasi-linear heat equation.


title:
Comparing the light curves of simulated Type Ia Supernovae with
  observations using data-driven models

abstract:
  We propose a robust, quantitative method to compare the synthetic light
curves of a Type Ia Supernova (SNIa) explosion model with a large set of
observed SNeIa, and derive a figure of merit for the explosion model's
agreement with observations. The synthetic light curves are fit with the
data-driven model SALT2 which returns values for stretch, color, and magnitude
at peak brightness, as well as a goodness-of-fit parameter. Each fit is
performed multiple times with different choices of filter bands and epoch range
in order to quantify the systematic uncertainty on the fitted parameters. We
use a parametric population model for the distribution of observed SNIa
parameters from large surveys, and extend it to represent red, dim, and bright
outliers found in a low-redshift SNIa data set. We discuss the potential
uncertainties of this population model and find it to be reliable given the
current uncertainties on cosmological parameters. Using our population model,
we assign each set of fitted parameters a likelihood of being observed in
nature, and a figure of merit based on this likelihood. We define a second
figure of merit based on the quality of the light curve fit, and combine the
two measures into an overall figure of merit for each explosion model. We
compute figures of merit for a variety of 1D, 2D and 3D explosion models and
show that our evaluation method allows meaningful inferences across a wide
range of light curve quality and fitted parameters.


title:
Pair potentials and equation of state of solid parahydrogen to megabar
  pressure

abstract:
  We compute by means of Quantum Monte Carlo simulations the equation of state
of bulk solid {para}hydrogen extrapolated to zero temperature, up to a pressure
of ~ 2 MBar. We compare the equation of state yielded by three different pair
potentials, namely the Silvera-Goldman, Buck and one recently proposed by
Moraldi, modified at short distances to include a repulsive core, missing in
the originally proposed potential. The Moraldi pair potential yields an
equation of state in very good agreement with experiment at megabar pressures,
owing to its softer core, and is at least as accurate as the SG or the Buck at
saturated vapour pressure. Estimates for the experimentally measurable kinetic
energy per molecule are provided for all pair potentials.


title: Risk Prediction of a Multiple Sclerosis Diagnosis

abstract:
  Multiple sclerosis (MS) is a chronic autoimmune disease that affects the
central nervous system. The progression and severity of MS varies by
individual, but it is generally a disabling disease. Although medications have
been developed to slow the disease progression and help manage symptoms, MS
research has yet to result in a cure. Early diagnosis and treatment of the
disease have been shown to be effective at slowing the development of
disabilities. However, early MS diagnosis is difficult because symptoms are
intermittent and shared with other diseases. Thus most previous works have
focused on uncovering the risk factors associated with MS and predicting the
progression of disease after a diagnosis rather than disease prediction. This
paper investigates the use of data available in electronic medical records
(EMRs) to create a risk prediction model; thereby helping clinicians perform
the difficult task of diagnosing an MS patient. Our results demonstrate that
even given a limited time window of patient data, one can achieve reasonable
classification with an area under the receiver operating characteristic curve
of 0.724. By restricting our features to common EMR components, the developed
models also generalize to other healthcare systems.


title:
A closed form analytical solution to the radiation problem from a short
  dipole antenna above flat ground using spectral domain approach

abstract:
  In this paper we consider the problem of radiation from a vertical short
dipole above flat ground with losses, which represents the well known in the
literature Sommerfeld radiation problem. We end up with a closed form
analytical solution to the above problem for the received electric and magnetic
field vectors above the ground in the far field area. The method of solution is
formulated in the spectral domain, and by inverse three dimensional Fourier
transformation and subsequent application of the Stationary Phase Method the
final solutions in the physical space are derived. To our knowledge, the above
closed form solutions are novel in the literature for the Sommerfeld radiation
problem. Finally, the physical interpretation for the received fields formulae
derived this paper are provided.


title: EDM Signatures of PeV-scale Superpartners

abstract:
  A possible supersymmetric interpretation of the new Higgs-like 126 GeV
resonance involves a high sfermion mass scale, from tens of TeV to a PeV or
above. This scale provides sufficiently large loop corrections to the Higgs
mass and can naturally resolve the constraints from flavor-violating
observables, even with a generic flavor structure in the sfermion sector. We
point out that such high scales could still generate CP-violating electric
dipole moments (EDMs) at interesting levels due to the enhancement of
left-right (LR) sfermion mixing. We illustrate this by saturating the light
fermion mass corrections from the sfermion threshold, leaving the gaugino
masses unconstrained. In this framework, we find that the current EDM bounds
probe energy scales of 0.1 PeV or higher; this is competitive with the reach of
$\epsilon_K$ and more sensitive than other hadronic and leptonic flavor
observables. We also consider the sensitivity to higher dimensional
supersymmetric operators in this scenario, including those that lead to proton
decay.


title:
Analytic Q-ball solutions and their stability in a piecewise parabolic
  potential

abstract:
  Explicit solutions for extended objects of a Q-ball type were found
analytically in a model describing complex scalar field with piecewise
parabolic potential in (3+1)- and (1+1)-dimensional space-times. Such a
potential provides a variety of solutions which were thoroughly examined. It
was shown that, depending on the values of the parameters of the model and
according to the known stability criteria, there exist stable and unstable
solutions. The classical stability of solutions in (1+1)-dimensional space-time
was examined in the linear approximation and it was shown explicitly that the
spectrum of linear perturbations around some solutions contains exponentially
growing modes while it is not so for other solutions.


title:
Detection of Nanoparticles with a Frequency Locked Whispering Gallery
  Mode Microresonator

abstract:
  We detect 39 nm x 10 nm gold nanorods using a microtoroid stabilized via the
Pound-Drever-Hall method. Real-time detection is achieved with signal-to-noise
ratios up to 12.2. These nanoparticles are a factor of three smaller in volume
than any other nanoparticle detected using WGM sensing to date. We show through
repeated experiments that the measurements are reliable, and verify the
presence of single nanorods on the microtoroid surface using electron
microscopy. At our current noise level, the plasmonic enhancement of these
nanorods could enable detection of proteins with radii as small as a = 2 nm.


title:
Antiferromagnetic ordering of dangling-bond electrons at the stepped
  Si(001) surface

abstract:
  Using first-principles density-functional calculations, we explore the
possibility of magnetic order at the rebonded $D_B$ step of the Si(001)
surface. The rebonded $D_B$ step containing threefold coordinated Si atoms can
be treated as a one-dimensional dangling-bond (DB) wire along the step edge. We
find that Si atoms composing the step edge are displaced up and down
alternatively due to Jahn-Teller-like distortion, but, if Si dimers on the
terrace are passivated by H atoms, the antiferromagnetic (AFM) order can be
stabilized at the step edge with a suppression of Jahn-Teller-like distortion.
We also find that the energy preference of AFM order over Jahn-Teller-like
distortion is enhanced in an oscillatory way as the length of DB wires
decreases, showing the so-called quantum size effects.


title:
Mid-infrared microlensing of accretion disc and dusty torus in quasars:
  effects on flux ratio anomalies

abstract:
  Multiply-imaged quasars and AGNs observed in the mid-infrared (MIR) range are
commonly assumed to be unaffected by the microlensing produced by the stars in
their lensing galaxy. In this paper, we investigate the validity domain of this
assumption. Indeed, that premise disregards microlensing of the accretion disc
in the MIR range, and does not account for recent progress in our knowledge of
the dusty torus. To simulate microlensing, we first built a simplified image of
the quasar composed of an accretion disc, and of a larger ring-like torus. The
mock quasars are then microlensed using an inverse ray-shooting code. We
simulated the wavelength and size dependence of microlensing for different
lensed image types and fraction of compact objects projected in the lens. This
allows us to derive magnification probabilities as a function of wavelength, as
well as to calculate the microlensing-induced deformation of the spectral
energy distribution of the lensed images. We find that microlensing variations
as large as 0.1 mag are very common at 11 microns (observer-frame). The main
signal comes from microlensing of the accretion disc, which may be significant
even when the fraction of flux from the disc is as small as 5 % of the total
flux. We also show that the torus of sources with Lbol <~ 10^45 erg/s is
expected to be noticeably microlensed. Microlensing may thus be used to get
insight into the rest near-infrared inner structure of AGNs. Finally, we
investigate whether microlensing in the mid-infrared can alter the so-called
Rcusp relation that links the fluxes of the lensed images triplet produced when
the source lies close to a cusp macro-caustic. This relation is commonly used
to identify massive (dark-matter) substructures in lensing galaxies. We find
that significant deviations from Rcusp may be expected, which means that
microlensing can explain part of the flux ratio problem.


title: Massive gravity coupled to DBI Galileons is ghost free

abstract:
  It is possible to couple Dirac-Born-Infeld (DBI) scalars possessing
generalized Galilean internal shift symmetries (Galileons) to nonlinear massive
gravity in four dimensions, in such a manner that the interactions maintain the
Galilean symmetry. Such a construction is of interest because it is not
possible to couple such fields to massless General Relativity in the same way.
We show that this theory has the primary constraint necessary to eliminate the
Boulware-Deser ghost, thus preserving the attractive properties of both the
Galileons and ghost-free massive gravity.


title:
Towards understanding the relation between the gas and the attenuation
  in galaxies at kpc scales

abstract:
  [abridged]
  Aims. The aim of the present paper is to provide new and more detailed
relations at the kpc scale between the gas surface density and the face-on
optical depth directly calibrated on galaxies, in order to compute the
attenuation not only for semi-analytic models but also observationally as new
and upcoming radio observatories are able to trace gas ever farther in the
Universe.
  Methods. We have selected a sample of 4 nearby resolved galaxies and a sample
of 27 unresolved galaxies from the Herschel Reference Survey and the Very
Nearby Galaxies Survey, for which we have a large set of multi-wavelength data
from the FUV to the FIR including metallicity gradients for resolved galaxies,
along with radio HI and CO observations. For each pixel in resolved galaxies
and for each galaxy in the unresolved sample, we compute the face-on optical
depth from the attenuation determined with the CIGALE SED fitting code and an
assumed geometry. We determine the gas surface density from HI and CO
observations with a metallicity-dependent XCO factor.
  Results. We provide new, simple to use, relations to determine the face-on
optical depth from the gas surface density, taking the metallicity into
account, which proves to be crucial for a proper estimate. The method used to
determine the gas surface density or the face-on optical depth has little
impact on the relations except for galaxies that have an inclination over 50d.
Finally, we provide detailed instructions on how to compute the attenuation
practically from the gas surface density taking into account possible
information on the metallicity.
  Conclusions. Examination of the influence of these new relations on simulated
FUV and IR luminosity functions shows a clear impact compared to older oft-used
relations, which in turn could affect the conclusions drawn from studies based
on large scale cosmological simulations.


title: DASCH 100-yr light curves of high-mass X-ray binaries

abstract:
  We analyzed the 100-yr light curves of Galactic high-mass X-ray binaries
using the Harvard photographic plate collection, made accessible through the
DASCH project (Digital Access to a Sky Century at Harvard). As scanning is
still in progress, we focus on the four objects that are currently well
covered: the supergiant X-ray binary Cyg X-1 (V1357 Cyg), and the Be X-ray
binaries 1H 1936+541 (BD+53 2262), RX J1744.7-2713 (HD 161103), and RX
J2030.5+4751 (SAO 49725), the latter two objects being similar to gamma Cas.
The star associated with Cyg X-1 does not show evidence for variability with an
amplitude higher than 0.3 magnitude over a hundred years. We found significant
variability of one magnitude with timescales of more than 10 years for SAO
49725, as well as a possible period of 500-600 days and an amplitude of 0.05
magnitude that might be the orbital, or super-orbital period of the system. The
data is insufficient to conclude for HD 161103 but suggests a similar long-term
variability. We thus observe an additional characteristic of gamma Cas-like
objects: their long-term variability. This variability seems to be due to the
slow evolution of a decretion disk around the Be star, but may be triggered by
the presence of a compact object in the system, possibly a white dwarf. This
characteristic could be used to identify further similar objects otherwise
difficult to detect.


title:
Head-on collisions of white dwarfs in triple systems could explain type
  Ia supernova

abstract:
  Type Ia supernovae (SNe Ia), thermonuclear explosions of carbon-oxygen white
dwarfs (CO-WDs), are currently the best cosmological "standard candles", but
the triggering mechanism of the explosion is unknown. It was recently shown
that the rate of head-on collisions of typical field CO-WDs in triple systems
may be comparable to the SNe Ia rate. Here we provide evidence supporting a
scenario in which the majority of SNe Ia are the result of such head-on
collisions of CO-WDs. In this case, the nuclear detonation is due to a well
understood shock ignition, devoid of commonly introduced free parameters such
as the deflagration velocity or transition to detonation criteria. By using
two-dimensional hydrodynamical simulations with a fully resolved ignition
process, we show that zero-impact-parameter collisions of typical CO-WDs with
masses $0.5-1\,M_{\odot}$ result in explosions that synthesize $^{56}$Ni masses
in the range of $\sim0.1-1\,M_{\odot}$, spanning the wide distribution of
yields observed for the majority of SNe Ia. All collision models yield the same
late-time ($>60$ days since explosion) bolometric light curve when normalized
by $^{56}$Ni masses (to better than $30\%$), in agreement with observations.
The calculated widths of the $^{56}$Ni-mass-weighted-line-of-sight velocity
distributions are correlated with the calculated $^{56}$Ni yield, agreeing with
the observed correlation. The strong correlation, shown here for the first
time, between $^{56}$Ni yield and total mass of the colliding CO-WDs
(insensitive to their mass ratio), is suggestive as the source for the
continuous distribution of observed SN Ia features, possibly including the
Philips relation.


title: Higgs Production Amidst the LHC Detector

abstract:
  We investigate the spectacular collider signatures of macroscopically
displaced, neutral particles that decay to Higgs bosons and missing energy. We
show that such long-lived particles arise naturally in a very minimal extension
of the Standard Model with only two new fermions with electroweak interactions.
The lifetime of the long-lived neutral particles can range from 10^{-2} mm to
10^6 mm. In some regions of the parameter space, the exotic signals would have
already been selected by the ATLAS and CMS triggers in their 7 and 8 TeV runs,
hence hiding in the existing data. We also discuss the possibility of
explaining the mild anomalies observed in the diphoton Higgs channel and the WW
production at the LHC.


title:
Synchrotron and inverse-Compton emission from blazar jets - III.
  Compton-dominant blazars

abstract:
  In this paper we develop the extended jet model of Potter & Cotter to model
the simultaneous multi-wavelength spectra of six Compton-dominant blazars. We
include an accelerating parabolic base transitioning to a slowly decelerating
conical jet with a geometry set by observations of M87 and consistent with
simulations and theory. We investigate several jet models and find that the
optically thick to thin synchrotron break in the radio spectrum requires the
jet to first come into equipartition at large distances along the jet (10^5
Schwarzschild radii), consistent with the observed transition from parabolic to
conical in the jet of M87. We confirm this result analytically and calculate
the expected frequency core-shift relations for the models under consideration.
We find that a parabolic jet transitioning to a ballistic conical jet, which
starts in equipartition and becomes more particle dominated at larger
distances, fits the multiwavelength data of the six blazars well, whilst an
adiabatic equipartition conical section requires very large bulk Lorentz
factors to reproduce the Compton-dominance of the blazars.
  We find that all these blazars require high power, high bulk Lorentz factor
jets observed close to the line of sight as we expect from the blazar sequence
and consistent with the results from Paper II. The inverse-Compton emission in
our fits is due to inverse-Compton scattering of high-redshift CMB photons at
large distances along the jet due to the high bulk Lorentz factors of the jets.
We postulate a new interpretation of the blazar sequence based on the radius of
the transition region of the jet (where the jet is brightest in synchrotron
emission) scaling linearly with black hole mass.


title: The Impact of Starbursts on the Circumgalactic Medium

abstract:
  We present a study exploring the impact of a starburst on the properties of
the surrounding circum-galactic medium (CGM): gas located beyond the galaxy's
stellar body and extending out to the virial radius (200 kpc). We obtained
ultraviolet spectroscopic data from the Cosmic Origin Spectrograph (COS)
probing the CGM of 20 low-redshift foreground galaxies using background QSOs.
Our sample consists of starburst and control galaxies. The latter comprises
normal star-forming and passive galaxies with similar stellar masses and impact
parameters as the starbursts. We used optical spectra from the Sloan Digital
Sky Survey(SDSS) to estimate the properties of the starbursts, inferring
average ages of 200 Myrs and burst fractions involving ~10% of their stellar
mass. The COS data reveal highly ionized gas traced by CIV in 80%(4/5) of the
starburst and in 17%(2/12) of the control sample. The two control galaxies with
CIV absorbers differed from the four starbursts in showing multiple
low-ionization transitions and strong saturated Lyman-alpha lines. They
therefore appear to be physically different systems. We show that the CIV
absorbers in the starburst CGM represent a significant baryon repository. The
high detection rate of this highly ionized material in the starbursts suggests
that starburst-driven winds can affect the CGM out to radii as large as 200
kpc. This is plausible given the inferred properties of the starbursts and the
known properties of starburst-driven winds. This would represent the first
direct observational evidence of local starbursts impacting the bulk of their
gaseous halos, and as such provides new evidence of the importance of this kind
of feedback in the evolution of galaxies.