title:
Induced transparency by coupling of Tamm and defect states in tunable
  terahertz plasmonic crystals

abstract:
  Photonic crystals and metamaterials have emerged as two classes of tailorable
materials that enable precise control of light. Plasmonic crystals, which can
be thought of as photonic crystals fabricated from plasmonic materials, Bragg
scatter incident electromagnetic waves from a repeated unit cell. However,
plasmonic crystals, like metamaterials, are composed of subwavelength unit
cells. Here, we study terahertz plasmonic crystals of several periods in a two
dimensional electron gas. This plasmonic medium is both extremely subwavelength
($\approx \lambda/100$) and reconfigurable through the application of voltages
to metal electrodes. Weakly localized crystal surface states known as Tamm
states are observed. By introducing an independently controlled plasmonic
defect that interacts with the Tamm states, we demonstrate a frequency agile
electromagnetically induced transparency phenomenon. The observed 50% ${\it
in-situ}$ tuning of the plasmonic crystal band edges should be realizable in
materials such as graphene to actively control the plasmonic crystal dispersion
in the infrared.


title: Partial Balayage and a Generalization of the Divisible Sandpile Model

abstract:
  In recent work by L. Levine and Y. Peres, it was observed that three models
for particle aggregation on the lattice - the divisible sandpile, rotor-router
aggregation, and internal diffusion limited aggregation - share a common
scaling limit as the lattice spacing tends to zero, if they are started with
the same initial mass configuration. It is straightforward to observe that this
scaling limit is precisely the same as the potential-theoretic operation of
taking the partial balayage of this initial mass configuration to the Lebesgue
measure. However, from the theory of the partial balayage operation it is clear
that one may take the partial balayage of a mass configuration to a more
general measure than the Lebesgue measure, which one cannot do for the three
aggregation models described by Levine and Peres. In this paper we therefore
generalize one of these models, the divisible sandpile model, in mainly a
bounded setting, and show that a natural scaling limit of this generalization
is given by a general partial balayage operation.


title: On the Capacity Region of Multiple Access Channel

abstract:
  The capacity region of a multiple access channel is discussed. It was found
that orthogonal multiple access and non orthogonal multiple access have the
same capacity region under the constraint of same sum power.


title:
Heat Kernels, Solvable Lie Groups, and the Mean Reverting SABR
  Stochastic Volatility Model

abstract:
  We use commutator techniques and calculations in solvable Lie groups to
investigate certain evolution Partial Differential Equations (PDEs for short)
that arise in the study of stochastic volatility models for pricing contingent
claims on risky assets. In particular, by restricting to domains of bounded
volatility, we establish the existence of the semi-groups generated by the
spatial part of the operators in these models, concentrating on those arising
in the so-called "SABR stochastic volatility model with mean reversion." The
main goal of this work is to approximate the solutions of the Cauchy problem
for the SABR PDE with mean reversion, a parabolic problem the generator of
which is denoted by $L$. The fundamental solution for this problem is not known
in closed form. We obtain an approximate solution by performing an expansion in
the so-called volvol or volatility of the volatility, which leads us to study a
degenerate elliptic operator $L_0$, corresponding the the zero-volvol case of
the SABR model with mean reversion, to which the classical results do not
apply. However, using Lie algebra techniques we are able to derive an exact
formula for the solution operator of the PDE $\partial_t u - L_0 u = 0$. We
then compare the semi-group generated by $L$--the existence of which does
follows from standard arguments--to that generated by $L_0$, thus establishing
a perturbation result that is useful for numerical methods for the SABR PDE
with mean reversion. In the process, we are led to study semigroups arising
from both a strongly parabolic and a hyperbolic problem.


title: Quantum Racah matrices and 3-strand braids in irreps R with |R|=4

abstract:
  We describe the inclusive Racah matrices for the first non-(anti)symmetric
rectangular representation R=[2,2] for quantum groups U_q(sl_N). Most of them
have sizes 2, 3, and 4 and are fully described by the eigenvalue hypothesis. Of
two 6x6 matrices, one is also described in this way, but the other one
corresponds to the case of degenerate eigenvalues and is evaluated by the
highest weight method. Together with the much harder calculation for R=[3,1] in
arXiv:1605.02313 and with the new method to extract exclusive matrices S and
\bar S from the inclusive ones, this completes the story of Racah matrices for
|R|\leq 4 and allows one to calculate and investigate the corresponding colored
HOMFLY polynomials for arbitrary 3-strand and arborescent knots.


title:
How Logic Interacts with Geometry: Infinitesimal Curvature of
  Categorical Spaces

abstract:
  In category theory, logic and geometry cooperate with each other producing
what is known under the name Synthetic Differential Geometry (SDG). The main
difference between SDG and standard differential geometry is that the
intuitionistic logic of SDG enforces the existence of infinitesimal objects
which essentially modify the local structure of spaces considered in SDG. We
focus on an "infinitesimal version" of SDG, an infinitesimal $n$-dimensional
formal manifold, and develop differential geometry on it. In particular, we
show that the Riemann curvature tensor on infinitesimal level is itself
infinitesimal. We construct a heuristic model $S^3 \times \mathbb{R} \subset
\mathbb{R}^4$ and study it from two perspectives: the perspective of the
category SET and that of the so-called topos $\mathcal{G}$ of germ-determined
ideals. We show that the fact that in this model the curvature tensor is
infinitesimal (in $\mathcal{G}$-perspective) eliminates the existing
singularity. A surprising effect is that the hybrid geometry based on the
existence of the infinitesimal and the SET levels generates an exotic smooth
structure on $\mathbb{R}^4$. We briefly discuss the obtained results and
indicate their possible applications.


title:
Non existence of Type II singularities for embedded and unknotted space
  curves

abstract:
  In this paper we prove that a certain class of embedded unknotted curves in
$\mathbb{R}^3$ evolving under curve shortening flow do not form singularities
Type II before collapsing to a point. Our proof uses tools of the minimal
surface theory to study a suitable isoperimetric ratio.


title:
Interferometric Measurement of Far Infrared Plasmons via Resonant
  Homodyne Mixing

abstract:
  We present an electrically tunable terahertz two dimensional plasmonic
interferometer with an integrated detection element that down converts the
terahertz fields to a DC signal. The integrated detector utilizes a resonant
plasmonic homodyne mixing mechanism that measures the component of the plasma
waves in-phase with an excitation field functioning as the local oscillator.
Plasmonic interferometers with two independently tuned paths are studied. These
devices demonstrate a means for developing a spectrometer-on-a-chip where the
tuning of electrical length plays a role analogous to that of physical path
length in macroscopic Fourier transform interferometers.


title: Partial Balayage on Riemannian Manifolds

abstract:
  A general theory of partial balayage on Riemannian manifolds is developed,
with emphasis on compact manifolds. Partial balayage is an operation of
sweeping measures, or charge distributions, to a prescribed density, and it is
closely related to (construction of) quadrature domains for subharmonic
functions, growth processes such as Laplacian growth and to weighted
equilibrium distributions.
  Several examples are given in the paper, as well as some specific results.
For instance, it is proved that, in two dimensions, harmonic and geodesic balls
are the same if and only if the Gaussian curvature of the manifold is constant.


title: New investigations on the transverse spin of structured optical fields

abstract:
  Guided waves and surface waves can be taken as two typical examples of
structured optical fields with the transverse spin. Analytical derivations are
developed to demonstrate that (i) guided waves also carry the transverse spin
that depends on the mean direction of propagation, which may have important
applications in spin-dependent unidirectional optical interfaces; (ii) the
quantization form of the transverse spin is for the first time revealed, which
is not obvious and related to an ellipticity; (iii) from a unified point of
view, the transverse spin can be attributed to the presence of an effective
rest mass of structured optical fields; (iv) the transverse spin can also be
described by the spin matrix of the photon field; (v) unlike a free optical
field whose spin projection on the propagation direction is the only
observable, owing to the effective rest mass, the spin projection of structured
optical fields on other directions is also an observable, such that one can
develop an optical analogy of spintronics. A preliminary idea about the
potential applications of the transverse spin is presented, but an in-depth and
complete study will be presented in our next work.


title:
Analysis of strategic and deterrence equilibrium by modeling with a Van
  der Waals gas

abstract:
  In this paper we are going to propose a physical model that can represent a
simple deterrence equilibrium situation, it is on based theory of unitary
rational actors. This theory takes in account that a state is composed of a
large number of people and a detailed study of the dynamics of any individual
it is impossible. This situation, in Physics, is similar for gases, which are
composed by a huge number of molecules and the study dynamics for one is
impossible. Then a common approach, in this case, is the thermodynamics one. We
only look to the macroscopic properties of the gas such as pressure,
temperature and volume. Then in this sense thermodynamics could help to use
theory of unitary rational actors also considering some non-rational factors.
Firstly we are going to see how this model represents the Mutual assured
destruction (MAD) theory if the influence of internal (economical,
political,due to non state actors) instability and o conventional military
forces are not taken in account. Secondly we are going to consider the factors
just mentioned in our model and we are going to study their influence on
deterrence stability: MAD will not be anymore effective. Finally we emphasize
that the proposed model can simulate the reaction to the interest of a
neighbour state or the international community on the deterrence equilibrium
situation. In particular we are going to apply this model to the India-Pakistan
deterrence equilibrium and see how the influence of International soft
diplomacy can change the situation.


title: A topological version of Hilbert's Nullstellensatz

abstract:
  We prove that the space of radical ideals of a ring $R$, endowed with the
hull-kernel topology, is a spectral space, and that it is canonically
homeomorphic to the space of the nonempty Zariski closed subspaces of
Spec$(R)$, endowed with a Zariski-like topology.


title:
What is Physics: The individual and the universal, and seeing past the
  noise

abstract:
  Along with weaving together observations, experiments, and theoretical
constructs into a coherent mesh of understanding of the world around us,
physics over its past five centuries has continuously refined the base concepts
on which the whole framework is built. In quantum physics, first in
non-relativistic mechanics and later in quantum field theories, even familiar
concepts of position, momentum, wave or particle, are derived constructs from
the classical limit in which we live but not intrinsic to the underlying
physics. Most crucially, the very idea of the individual, whether an object or
an event, distinguished only in a mere label of identity from others identical
to it in all the physics, exists only as an approximation, not an element of
underlying reality. Failure to recognize this and seeking alternative
explanations in many worlds or multiverses leads only to incoherent logic and
incorrect physics.
  As an example, in a physical system such as an atom in a particular state,
physics deals with the universal system of all such atoms but makes no
meaningful prediction of the position of an electron or the time of decay of
any specific atom. Those are incidental, entirely random among all possible
positions and times, even while physics makes very precise predictions for the
distribution of the outcomes in measurements on atoms in that state. Physics
deals with the universal, not the individual.


title:
Eco-Strategy: Towards a New Generation Managerial Model Based on Green
  IT and CSR

abstract:
  The sustainable development strategy in the management of information and
communication technology (ICT) is an advanced research sector which provides a
theoretical framework for integrating social and environmental responsibilities
of business in the development and implementation of the management strategy.
This article offers an original management model that integrates the Corporate
Social Responsibility (CSR) approach and Green IT, which enables decision
makers, governance and strategic alignment of ICT, business and sustainability.
The model offers a new vision of decision making through economic opportunities
and increasing pressure from stakeholders. This paper reveals the strategic
relevance of the model, on the basis of a literature review, and provides
guidelines for sustainable business development of effective management
systems, and improvement of the economic, social and environmental performance
of companies. The proposed framework provides a new generation managerial
approach to ICT management strategy that we call "Eco-Strategy".


title:
Some Explicit Formulas for Sums Involving the Binomial Coefficients with
  the Falling Factorial

abstract:
  Spivey presented a new approach to evaluate combinatorial sums by using
finite differences. We present some closed forms for sums involving the
binomial coefficients, Fibonacci and Lucas numbers in terms of the falling
factorial.


title:
Wolf-Rayet stars in M81: Detection and Characterization using GTC/OSIRIS
  spectra and HST/ACS images

abstract:
  We here report the properties of Wolf-Rayet (W-R) stars in 14 locations in
the nearby spiral galaxy M81. These locations were found serendipitously while
analysing the slit spectra of a sample of ~150 star-forming complexes, taken
using the long-slit and Multi-Object spectroscopic modes of the OSIRIS
instrument at the 10.4-m Gran Telescopio Canarias. Colours and magnitudes of
the identified point sources in the Hubble Space Telescope images compare well
with those of individual W-R stars in the Milky Way. Using templates of
individual W-R stars, we infer that the objects responsible for the observed
W-R features are single stars in 12 locations, comprising of 3 WNLs, 3 WNEs, 2
WCEs and 4 transitional WN/C types. In diagrams involving bump luminosities and
the width of the bumps, the W-R stars of the same sub-class group together,
with the transitional stars occupying locations intermediate between the WNE
and WCE groups, as expected from the evolutionary models. However, the observed
number of 4 transitional stars out of our sample of 14 is statistically high as
compared to the 4% expected in stellar evolutionary models.


title:
The impact of heating the breakdown bubble on the global mode of a
  swirling jet: Experiments and linear stability analysis

abstract:
  This study investigates the dynamics of non-isothermal swirling jets
undergoing vortex breakdown, with an emphasis on helical coherent structures.
It is proposed that the dominant helical coherent structure can be suppressed
by heating the recirculation bubble. This proposition is assessed with Stereo
Particle Image Velocimetry (PIV) measurements of the breakdown region of
isothermal and heated swirling jets. The coherent kinetic energy of the
dominant helical structure was derived from PIV snapshots via Proper Orthogonal
Decomposition. For one set of experimental parameters, mild heating is found to
increase the energy content of the dominant helical mode. Strong heating leads
to a reduction by 30\% of the coherent structures energy. For a second set of
experimental parameters, no alteration of the dominant coherent structure is
detectable. Local linear stability analysis of the time-averaged velocity
fields shows that the key difference between the two configurations is the
density ratio at the respective wavemaker location. A density ratio of
approximately 0.8 is found to correlate to a suppression of the global mode in
the experiments. A parametric study with model density and velocity profiles
indicates the most important parameters that govern the local absolute growth
rate: The density ratio and the relative position of the density profiles and
the inner shear layer.


title:
Cosmic-ray energy spectrum and composition up to the ankle - the case
  for a second Galactic component

abstract:
  We have carried out a detailed study to understand the observed energy
spectrum and composition of cosmic rays with energies up to ~10^18 eV. Our
study shows that a single Galactic component with subsequent energy cut-offs in
the individual spectra of different elements, optimised to explain the observed
spectra below ~10^14 eV and the knee in the all-particle spectrum, cannot
explain the observed all-particle spectrum above ~2x10^16 eV. We discuss two
approaches for a second component of Galactic cosmic rays -- re-acceleration at
a Galactic wind termination shock, and supernova explosions of Wolf-Rayet
stars, and show that the latter scenario can explain almost all observed
features in the all-particle spectrum and the composition up to ~10^18 eV, when
combined with a canonical extra-galactic spectrum expected from strong radio
galaxies or a source population with similar cosmological evolution. In this
two-component Galactic model, the knee at ~ 3x10^15 eV and the second knee at
~10^17 eV in the all-particle spectrum are due to the cut-offs in the first and
second components, respectively. We also discuss several variations of the
extra-galactic component, from a minimal contribution to scenarios with a
significant component below the ankle (at ~4x10^18 eV), and find that
extra-galactic contributions in excess of regular source evolution are neither
indicated nor in conflict with the existing data. Our main result is that the
second Galactic component predicts a composition of Galactic cosmic rays at and
above the second knee that largely consists of helium or a mixture of helium
and CNO nuclei, with a weak or essentially vanishing iron fraction, in contrast
to most common assumptions. This prediction is in agreement with new
measurements from LOFAR and the Pierre Auger Observatory which indicate a
strong light component and a rather low iron fraction between ~10^17 and 10^18
eV.


title: Integral means spectrum of whole-plane SLE

abstract:
  We complete the mathematical analysis of the fine structure of harmonic
measure on SLE curves that was initiated by Beliaev and Smirnov, as described
by the averaged integral means spectrum. For the unbounded version of
whole-plane SLE as studied by Duplantier, Nguyen, Nguyen and Zinsmeister, and
Loutsenko and Yermolayeva, a phase transition has been shown to occur for high
enough moments from the bulk spectrum towards a novel spectrum related to the
point at infinity. For the bounded version of whole-plane SLE studied here, a
similar transition phenomenon, now associated with the SLE origin, is proved to
exist for low enough moments, but we show that it is superseded by the earlier
occurrence of the transition to the SLE tip spectrum.


title:
Liftings of Nichols algebras of diagonal type II. All liftings are
  cocycle deformations

abstract:
  We classify finite-dimensional pointed Hopf algebras with abelian coradical,
up to isomorphism, and show that they are cocycle deformations of the
associated graded Hopf algebra.
  More generally, for any braided vector space of diagonal type $V$ with a
principal realization in the category of Yetter-Drinfeld modules of a
cosemisimple Hopf algebra $H$ and such that the Nichols algebra
$\mathfrak{B}(V)$ is finite-dimensional, thus presented by a finite set
$\mathcal G$ of relations, we define a family of Hopf algebras
$\mathfrak{u}(\boldsymbol\lambda)$, $\boldsymbol\lambda\in \Bbbk^{\mathcal G}$,
which are cocycle deformations of $\mathfrak{B}(V)\# H$ and such that
$\operatorname{gr}\mathfrak{u}(\boldsymbol\lambda)\simeq \mathfrak{B}(V)\# H$.


title:
Selective coherent phonon mode generation in single wall carbon
  nanotubes

abstract:
  The pulse-train technique within ultrafast pump-probe spectroscopy is
theoretically investigated to enhance a specific coherent phonon mode while
suppressing the other phonon modes generated in single wall carbon nanotubes
(SWNTs). In particular, we focus on the selectivity of the radial breathing
mode (RBM) and the G-band for a given SWNT. We find that if the repetition
period of the pulse train matches with integer multiple of the RBM phonon
period, the RBM amplitude could be kept while the amplitudes of the other modes
are suppressed. As for the G-band, when we apply a repetition period of
half-integer multiple of the RBM period, the RBM could be suppressed because of
destructive interference, while the G-band still survives. It is also possible
to keep the G-band and suppress the RBM by applying a repetition period that
matches with integer multiple of the G-band phonon period. However, in this
case we have to use a large number of laser pulses having a property of "magic
ratio" of the G-band and RBM periods.


title:
Model-based versus model-free control designs for improving microalgae
  growth in a closed photobioreactor: Some preliminary comparisons

abstract:
  Controlling microalgae cultivation, i.e., a crucial industrial topic today,
is a challenging task since the corresponding modeling is complex, highly
uncertain and time-varying. A model-free control setting is therefore
introduced in order to ensure a high growth of microalgae in a continuous
closed photobioreactor. Computer simulations are displayed in order to compare
this design to an input-output feedback linearizing control strategy, which is
widely used in the academic literature on photobioreactors. They assess the
superiority of the model-free standpoint both in terms of performances and
implementation simplicity.


title:
CALIPER: Continuous Authentication Layered with Integrated PKI Encoding
  Recognition

abstract:
  Architectures relying on continuous authentication require a secure way to
challenge the user's identity without trusting that the Continuous
Authentication Subsystem (CAS) has not been compromised, i.e., that the
response to the layer which manages service/application access is not fake. In
this paper, we introduce the CALIPER protocol, in which a separate Continuous
Access Verification Entity (CAVE) directly challenges the user's identity in a
continuous authentication regime. Instead of simply returning authentication
probabilities or confidence scores, CALIPER's CAS uses live hard and soft
biometric samples from the user to extract a cryptographic private key embedded
in a challenge posed by the CAVE. The CAS then uses this key to sign a response
to the CAVE. CALIPER supports multiple modalities, key lengths, and security
levels and can be applied in two scenarios: One where the CAS must authenticate
its user to a CAVE running on a remote server (device-server) for access to
remote application data, and another where the CAS must authenticate its user
to a locally running trusted computing module (TCM) for access to local
application data (device-TCM). We further demonstrate that CALIPER can leverage
device hardware resources to enable privacy and security even when the device's
kernel is compromised, and we show how this authentication protocol can even be
expanded to obfuscate direct kernel object manipulation (DKOM) malwares.


title:
A new integral-series identity of multiple zeta values and
  regularizations

abstract:
  We present a new "integral=series" type identity of multiple zeta values, and
show that this is equivalent in a suitable sense to the fundamental theorem of
regularization. We conjecture that this identity is enough to describe all
linear relations of multiple zeta values over Q. We also establish the
regularization theorem for multiple zeta-star values, which too is equivalent
to our new identity. A connection to Kawashima's relation is discussed as well.


title:
Position and mode dependent coupling of terahertz quantum cascade laser
  fields to an integrated diode

abstract:
  A Schottky diode integrated into a terahertz quantum cascade laser waveguide
couples directly to the internal laser fields. In a multimode laser, the diode
response is correlated with both the instantaneous power and the coupling
strength to the diode of each lasing mode. Measurements of the rectified
response of diodes integrated in two quantum cascade laser cavities at
different locations indicate that the relative diode position strongly
influences the laser-diode coupling.


title: Steric effects induce geometric remodeling of actin bundles in filopodia

abstract:
  Filopodia are ubiquitous fingerlike protrusions, spawned by many eukaryotic
cells, to probe and interact with their environments. Polymerization dynamics
of actin filaments, comprising the structural core of filopodia, largely
determine their instantaneous lengths and overall lifetimes. The polymerization
reactions at the filopodial tip require transport of G-actin, which enter the
filopodial tube from the filopodial base and diffuse toward the filament barbed
ends near the tip. Actin filaments are mechanically coupled into a tight bundle
by cross-linker proteins. Interestingly, many of these proteins are relatively
short, restricting the free diffusion of cytosolic G-actin throughout the
bundle and, in particular, its penetration into the bundle core. To investigate
the effect of steric restrictions on G-actin diffusion by the porous structure
of filopodial actin filament bundle, we used a particle-based stochastic
simulation approach. We discovered that excluded volume interactions result in
partial and then full collapse of central filaments in the bundle, leading to a
hollowed-out structure. The latter may further collapse radially due to the
activity of cross-linking proteins, hence producing conical-shaped filament
bundles. Interestingly, electron microscopy experiments on mature filopodia
indeed frequently reveal actin bundles that are narrow at the tip and wider at
the base. Overall, our work demonstrates that excluded volume effects in the
context of reaction-diffusion processes in porous networks may lead to
unexpected geometric growth patterns and complicated, history-dependent
dynamics of intermediate metastable configurations.


title:
A possible interpretation of the Higgs mass by the cosmological
  attractive relaxion

abstract:
  Recently, a novel idea has been proposed to relax the electroweak hierarchy
problem through the cosmological inflation and the axion periodic potential.
Here, we further assume that only the attractive inflation is needed to explain
the light mass of the Higgs boson, where we do not need a specified periodic
potential of the axion field. Attractive inflation during the early universe
drives the Higgs boson mass from the large value in the early universe to the
small value at present, where the Higgs mass is an evolving parameter of the
Universe. Thus, the small Higgs mass can technically originate from the
cosmological evolution rather than dynamical symmetry or anthropics. Further,
we study the possible collider signals or constraints at future lepton collier
and the possible constraints from the muon anomalous magnetic moment. A
concrete attractive relaxion model is also discussed, which is consistent with
the data of Planck 2015.


title: Space-time symmetric extension of non-relativistic quantum mechanics

abstract:
  In quantum theory we refer to the probability of finding a particle between
positions $x$ and $x+dx$ at the instant $t$, although we have no capacity of
predicting exactly when the detection occurs. In this work, first we present an
extended non-relativistic quantum formalism where space and time play
equivalent roles. It leads to the probability of finding a particle between $x$
and $x+dx$ during [$t$,$t+dt$]. Then, we find a Schr\"odinger-like equation for
a "mirror" wave function $\phi(t,x)$ associated with the probability of
measuring the system between $t$ and $t+dt$, given that detection occurs at
$x$. In this framework, it is shown that energy measurements of a stationary
state display a non-zero dispersion, and that energy-time uncertainty arises
from first principles. We show that a central result on arrival time, obtained
through approaches that resort to {\it ad hoc} assumptions, is a natural,
built-in part of the formalism presented here.


title:
Kernel-Based Structural Equation Models for Topology Identification of
  Directed Networks

abstract:
  Structural equation models (SEMs) have been widely adopted for inference of
causal interactions in complex networks. Recent examples include unveiling
topologies of hidden causal networks over which processes such as spreading
diseases, or rumors propagate. The appeal of SEMs in these settings stems from
their simplicity and tractability, since they typically assume linear
dependencies among observable variables. Acknowledging the limitations inherent
to adopting linear models, the present paper advocates nonlinear SEMs, which
account for (possible) nonlinear dependencies among network nodes. The
advocated approach leverages kernels as a powerful encompassing framework for
nonlinear modeling, and an efficient estimator with affordable tradeoffs is put
forth. Interestingly, pursuit of the novel kernel-based approach yields a
convex regularized estimator that promotes edge sparsity, and is amenable to
proximal-splitting optimization methods. To this end, solvers with
complementary merits are developed by leveraging the alternating direction
method of multipliers, and proximal gradient iterations. Experiments conducted
on simulated data demonstrate that the novel approach outperforms linear SEMs
with respect to edge detection errors. Furthermore, tests on a real gene
expression dataset unveil interesting new edges that were not revealed by
linear SEMs, which could shed more light on regulatory behavior of human genes.


title:
Rectified diode response of a multimode quantum cascade laser integrated
  terahertz transceiver

abstract:
  We characterized the DC transport response of a diode embedded in a THz
quantum cascade laser as the laser current was changed. The overall response is
described by parallel contributions from the rectification of the laser field
due to the non-linearity of the diode I-V and from thermally activated
transport. Sudden jumps in the diode response when the laser changes from
single mode to multi-mode operation, with no corresponding jumps in output
power, suggest that the coupling between the diode and laser field depends on
the spatial distribution of internal fields. The results demonstrate
conclusively that the internal laser field couples directly to the integrated
diode.


title:
PARAPH: Presentation Attack Rejection by Analyzing Polarization
  Hypotheses

abstract:
  For applications such as airport border control, biometric technologies that
can process many capture subjects quickly, efficiently, with weak supervision,
and with minimal discomfort are desirable. Facial recognition is particularly
appealing because it is minimally invasive yet offers relatively good
recognition performance. Unfortunately, the combination of weak supervision and
minimal invasiveness makes even highly accurate facial recognition systems
susceptible to spoofing via presentation attacks. Thus, there is great demand
for an effective and low cost system capable of rejecting such attacks.To this
end we introduce PARAPH -- a novel hardware extension that exploits different
measurements of light polarization to yield an image space in which
presentation media are readily discernible from Bona Fide facial
characteristics. The PARAPH system is inexpensive with an added cost of less
than 10 US dollars. The system makes two polarization measurements in rapid
succession, allowing them to be approximately pixel-aligned, with a frame rate
limited by the camera, not the system. There are no moving parts above the
molecular level, due to the efficient use of twisted nematic liquid crystals.
We present evaluation images using three presentation attack media next to an
actual face -- high quality photos on glossy and matte paper and a video of the
face on an LCD. In each case, the actual face in the image generated by PARAPH
is structurally discernible from the presentations, which appear either as
noise (print attacks) or saturated images (replay attacks).


title: Intuitionistic interpretation of quantum mechanics

abstract:
  In the present paper, the decision problem of the Schr\"odinger equation
(asking whether or not a given Hamiltonian operator has the nonempty solution
set) is represented as a logical statement. As it is shown in the paper, the
law of excluded middle would be applicable to the introduced statement if and
only if quantum fundamentalism (asserting that everything in the universe is
ultimately describable in quantum-mechanical terms) held. But, since the
decision problem of the Schr\"odinger equation is in general undecidable, such
a statement is allowed to be other than true or false, explicitly, it may fail
to have truth values at all. This makes possible to abandon the law of excluded
middle together with quantum fundamentalism in the proposed intuitionistic
interpretation of quantum mechanics.


title:
Magnetic-field-mediated coupling and control in hybrid
  atomic-nanomechanical systems

abstract:
  Magnetically coupled hybrid quantum systems enable robust quantum state
control through Landau-Zener transitions. Here, we show that an ultracold
atomic sample coupled to a nanomechanical resonator via oscillating magnetic
fields can be used to cool the resonator's mechanical motion, to measure the
mechanical temperature, and to enable entanglement of these mesoscopic objects.
We calculate the expected coupling for both permanent-magnet and
current-conducting nanostring resonators and describe how this hybridization is
attainable using recently developed fabrication techniques, including SiN
nanostrings and atom chips.


title:
On the existence of solutions for a generalized strong vector
  quasi-equilibrium problem

abstract:
  In this paper, we consider a generalized strong vector quasi-equilibrium
problem and we prove the existence of its solutions by using some suxiliary
results. One of the established theorems is proved by using an approximation
method.


title: Spacetimes Coverings and C-Boundary

abstract:
  We consider the relation between the c-completion of a Lorentz manifold V and
its quotient M = V/G, where G is an isometry group acting freely and properly
discontinuously. First, we consider the future causal completion case,
characterizing virtually when such a quotient is well behaved with the future
chronological topology and improving the existing results on the literature.
Secondly, we show that under some general assumptions, there exists an
homeomorphism and chronological isomorphism between both, the c-completion of M
and some adequate quotient of the c-completion of V defined by G. Our results
are optimal, as we show in several examples. Finally, we give a practical
application by considering isometric actions over Robertson-Walker spacetimes,
including in particular the Anti-de Sitter model.


title:
Directly characterizing the relative strength and momentum dependence of
  electron-phonon coupling using resonant inelastic x-ray scattering

abstract:
  The coupling between lattice and charge degrees of freedom in condensed
matter materials is ubiquitous and can often result in interesting properties
and ordered phases, including conventional superconductivity, charge density
wave order, and metal-insulator transitions. Angle-resolved photoemission
spectroscopy and both neutron and non-resonant x-ray scattering serve as
effective probes for determining the behavior of appropriate, individual
degrees of freedom -- the electronic structure and lattice excitation, or
phonon dispersion, respectively. However, each provides less direct information
about the mutual coupling between the degrees of freedom, usual through
self-energy effects, which tend to renormalize and broaden spectral features
precisely where the coupling is strong, impacting ones ability to quantitively
characterize the coupling. Here we demonstrate that resonant inelastic x-ray
scattering, or RIXS, can be an effective tool to directly determine the
relative strength and momentum dependence of the electron-phonon coupling in
condensed matter systems. Using a diagrammatic approach for an 8-band model of
copper oxides, we study the contributions from the lowest order diagrams to the
full RIXS intensity for a realistic scattering geometry, accounting for matrix
element effects in the scattering cross-section as well as the momentum
dependence of the electron-phonon coupling vertex. A detailed examination of
these maps offers a unique perspective into the characteristics of
electron-phonon coupling, which complements both neutron and non-resonant x-ray
scattering, as well as Raman and infrared conductivity.


title:
Uniqueness of complete maximal hypersurfaces in spatially open
  $(n+1)$-dimensional Robertson-Walker spacetimes with flat fiber

abstract:
  In this paper, under natural geometric and physical assumptions we provide
new uniqueness and non-existence results for complete maximal hypersurfaces in
spatially open Robertson-Walker spacetimes whose fiber is flat. Moreover, our
results are applied to relevant spacetimes as the steady state spacetime,
Einstein-de Sitter spacetime and radiation models.


title: Topological and geometric measurements of force chain structure

abstract:
  Developing quantitative methods for characterizing structural properties of
force chains in densely packed granular media is an important step toward
understanding or predicting large-scale physical properties of a packing. A
promising framework in which to develop such methods is network science, which
can be used to translate particle locations and force contacts to a graph in
which particles are represented by nodes and forces between particles are
represented by weighted edges. Applying network-based community-detection
techniques to extract force chains opens the door to developing statistics of
force chain structure, with the goal of identifying shape differences across
packings, and providing a foundation on which to build predictions of bulk
material properties from mesoscale network features. Here, we discuss a trio of
related but fundamentally distinct measurements of mesoscale structure of force
chains in arbitrary 2D packings, including a novel statistic derived using
tools from algebraic topology, which together provide a tool set for the
analysis of force chain architecture. We demonstrate the utility of this tool
set by detecting variations in force chain architecture with pressure.
Collectively, these techniques can be generalized to 3D packings, and to the
assessment of continuous deformations of packings under stress or strain.

categories: cond-mat.soft nlin.AO nlin.PS physics.data-an


title:
Coherent phenomena in terahertz 2D plasmonic structures: strong
  coupling, plasmonic crystals, and induced transparency by coupling of
  localized modes

abstract:
  The device applications of plasmonic systems such as graphene and two
dimensional electron gases (2DEGs) in III-V heterostructures include terahertz
detectors, mixers, oscillators and modulators. These two dimensional (2D)
plasmonic systems are not only well-suited for device integration, but also
enable the broad tunability of underdamped plasma excitations via an applied
electric field. We present demonstrations of the coherent coupling of multiple
voltage tuned GaAs/AlGaAs 2D plasmonic resonators under terahertz irradiation.
By utilizing a plasmonic homodyne mixing mechanism to downconvert the near
field of plasma waves to a DC signal, we directly detect the spectrum of
coupled plasmonic micro-resonator structures at cryogenic temperatures. The
2DEG in the studied devices can be interpreted as a plasmonic waveguide where
multiple gate terminals control the 2DEG kinetic inductance. When the gate
tuning of the 2DEG is spatially periodic, a one-dimensional finite plasmonic
crystal forms. This results in a subwavelength structure, much like a
metamaterial element, that nonetheless Bragg scatters plasma waves from a
repeated crystal unit cell. A 50% in situ tuning of the plasmonic crystal band
edges is observed. By introducing gate-controlled defects or simply terminating
the lattice, localized states arise in the plasmonic crystal. Inherent
asymmetries at the finite crystal boundaries produce an induced
transparency-like phenomenon due to the coupling of defect modes and crystal
surface states known as Tamm states. The demonstrated active control of coupled
plasmonic resonators opens previously unexplored avenues for sensitive direct
and heterodyne THz detection, planar metamaterials, and slow-light devices.


title: Economic Development and Inequality: a complex system analysis

abstract:
  By borrowing methods from complex system analysis, in this paper we analyze
the features of the complex relationship that links the development and the
industrialization of a country to economic inequality. In order to do this, we
identify industrialization as a combination of a monetary index, the GDP per
capita, and a recently introduced measure of the complexity of an economy, the
Fitness. At first we explore these relations on a global scale over the time
period 1990--2008 focusing on two different dimensions of inequality: the
capital share of income and a Theil measure of wage inequality. In both cases,
the movement of inequality follows a pattern similar to the one theorized by
Kuznets in the fifties. We then narrow down the object of study ad we
concentrate on wage inequality within the United States. By employing data on
wages and employment on the approximately 3100 US counties for the time
interval 1990--2014, we generalize the Fitness-Complexity algorithm for
counties and NAICS sectors, and we investigate wage inequality between
industrial sectors within counties. At this scale, in the early nineties we
recover a behavior similar to the global one. While, in more recent years, we
uncover a trend reversal: wage inequality monotonically increases as
industrialization levels grow. Hence at a county level, at net of the social
and institutional factors that differ among countries, we not only observe an
upturn in inequality but also a change in the structure of the relation between
wage inequality and development.


title:
Dehydration as a Universal Mechanism for Ion Selectivity in Graphene and
  Other Atomically Thin Pores

abstract:
  Ion channels play a key role in regulating cell behavior and in electrical
signaling. In these settings, polar and charged functional groups -- as well as
protein response -- compensate for dehydration in an ion-dependent way, giving
rise to the ion selective transport critical to the operation of cells.
Dehydration, though, yields ion-dependent free-energy barriers and thus is
predicted to give rise to selectivity by itself. However, these barriers are
typically so large that they will suppress the ion currents to undetectable
levels. Here, we establish that graphene displays a measurable dehydration-only
mechanism for selectivity of $\mathrm{K}^+$ over $\mathrm{Cl}^-$. This
fundamental mechanism -- one that depends only on the geometry and hydration --
is the starting point for selectivity for all channels and pores. Moreover,
while we study selectivity of $\mathrm{K}^+$ over $\mathrm{Cl}^-$, we find that
dehydration-based selectivity functions for all ions, i.e., cation over cation
selectivity (e.g., $\mathrm{K}^+$ over $\mathrm{Na}^+$). Its likely detection
in graphene pores resolves conflicting experimental results, as well as
presents a new paradigm for characterizing the operation of ion channels and
engineering molecular/ionic selectivity in filtration and other applications.


title:
Adjoint-based Gradient Estimation Using the Space-time Solutions of
  Unknown Conservation Law Simulations

abstract:
  Many control applications can be formulated as optimization constrained by
conservation laws. Such optimization can be efficiently solved by
gradient-based methods, where the gradient is obtained through the adjoint
method. Traditionally, the adjoint method has not been able to be implemented
in "gray-box" conservation law simulations. In gray-box simulations, the
analytical and numerical form of the conservation law is unknown, but the
space-time solution of relevant flow quantities is available. Without the
adjoint gradient, optimization can be challenging for problems with many
control variables. However, much information about the gray-box simulation is
contained in its space-time solution, which motivates us to estimate the
adjoint gradient by leveraging the space-time solution. This article considers
a type of gray-box simulations where the flux function is partially unknown. A
method is introduced to estimate the adjoint gradient at a cost independent of
the number of control variables. The method firstly infers a conservation law,
named the twin model, from the space-time solution, and then applies the
adjoint method to the inferred twin model to estimate the gradient. The method
is demonstrated to achieve good gradient estimation accuracies in several
numerical examples. The main contributions of this paper are: a twin model
method that enables the adjoint gradient computation for gray-box conservation
law simulations; and an adaptive basis construction scheme that fully exploits
the information of gray-box solutions.


title: Optical photometry and spectroscopy of the 1987A-like supernova 2009mw

abstract:
  We present optical photometric and spectroscopic observations of the
1987A-like supernova (SN) 2009mw. Our $BVRI$ and $g'r'i'z'$ photometry covers
167 days of evolution, including the rise to the light curve maximum, and ends
just after the beginning of the linear tail phase. We compare the observational
properties of SN 2009mw with those of other SNe belonging to the same subgroup,
and find that it shows similarities to several objects. The physical parameters
of the progenitor and the SN are estimated via hydrodynamical modelling,
yielding an explosion energy of $1$ foe, a pre-SN mass of $19\,{\rm
M_{\odot}}$, a progenitor radius as $30\,{\rm R_{\odot}}$ and a $^{56}$Ni mass
as $0.062\,{\rm M_{\odot}}$. These values indicate that the progenitor of SN
2009mw was a blue supergiant star, similar to the progenitor of SN 1987A. We
examine the host environment of SN 2009mw and find that it emerged from a
population with slightly sub-solar metallicty.


title:
$\mathrm{Pin}(2)$-monopole Floer homology, higher compositions and
  connected sums

abstract:
  We study the behavior of $\mathrm{Pin}(2)$-monopole Floer homology under
connected sums. After constructing a (partially defined)
$\mathcal{A}_{\infty}$-module structure on the $\mathrm{Pin}(2)$-monopole Floer
chain complex of a three manifold (in the spirit of Baldwin and Bloom's
monopole category), we identify up to quasi-isomorphism the Floer chain complex
of a connected sum with a version of the $\mathcal{A}_{\infty}$-tensor product
of the modules of the summands. There is an associated Eilenberg-Moore spectral
sequence converging to the Floer groups of the connected sum whose $E^2$ page
is the $\mathrm{Tor}$ of the Floer groups of the summands. We discuss in detail
a simple example, and use this computation to show that the
$\mathrm{Pin}(2)$-monopole Floer homology of $S^3$ has non trivial Massey
products


title:
Nanocavity optomechanical torque magnetometry and radiofrequency
  susceptometry

abstract:
  Nanophotonic optomechanical devices allow observation of nanoscale vibrations
with sensitivity that has dramatically advanced metrology of nanomechanical
structures [1-9] and has the potential to impact studies of nanoscale physical
systems in a similar manner [10, 11]. Here we demonstrate this potential with a
nanophotonic optomechanical torque magnetometer and radiofrequency (RF)
magnetic susceptometer. Exquisite readout sensitivity provided by a nanocavity
integrated within a torsional nanomechanical resonator enables observations of
the unique net magnetization and RF-driven responses of single mesoscopic
magnetic structures in ambient conditions. The magnetic moment resolution is
sufficient for observation of Barkhausen steps in the magnetic hysteresis of a
lithographically patterned permalloy island [12]. In addition, significantly
enhanced RF susceptibility is found over narrow field ranges and attributed to
thermally assisted driven hopping of a magnetic vortex core between neighboring
pinning sites [13]. The on-chip magneto-susceptometer scheme offers a promising
path to powerful integrated cavity optomechanical devices for quantitative
characterization of magnetic micro- and nanosystems in science and technology.


title: A note on stable sheaves on Enriques surfaces II

abstract:
  We shall study a necessary and sufficient condition for the existence of
stable sheaves on arbitrary Enriques surfaces.


title: Lectures on monopole Floer homology

abstract:
  These lecture notes are a friendly introduction to monopole Floer homology.
We discuss the relevant differential geometry and Morse theory involved in the
definition. After developing the relation with the four-dimensional theory, our
attention shifts to gradings and correction terms. Finally, we sketch the
analogue in this setup of Manolescu's recent disproof of the long standing
Triangulation Conjecture.


title: Error-correcting codes from $k$-resolving sets

abstract:
  We demonstrate a construction of error-correcting codes from graphs by means
of $k$-resolving sets, and present a decoding algorithm which makes use of
covering designs. Along the way, we determine the $k$-metric dimension of grid
graphs (i.e. Cartesian products of paths).


title: Self-Modification of Policy and Utility Function in Rational Agents

abstract:
  Any agent that is part of the environment it interacts with and has versatile
actuators (such as arms and fingers), will in principle have the ability to
self-modify -- for example by changing its own source code. As we continue to
create more and more intelligent agents, chances increase that they will learn
about this ability. The question is: will they want to use it? For example,
highly intelligent systems may find ways to change their goals to something
more easily achievable, thereby `escaping' the control of their designers. In
an important paper, Omohundro (2008) argued that goal preservation is a
fundamental drive of any intelligent system, since a goal is more likely to be
achieved if future versions of the agent strive towards the same goal. In this
paper, we formalise this argument in general reinforcement learning, and
explore situations where it fails. Our conclusion is that the self-modification
possibility is harmless if and only if the value function of the agent
anticipates the consequences of self-modifications and use the current utility
function when evaluating the future.


title: Avoiding Wireheading with Value Reinforcement Learning

abstract:
  How can we design good goals for arbitrarily intelligent agents?
Reinforcement learning (RL) is a natural approach. Unfortunately, RL does not
work well for generally intelligent agents, as RL agents are incentivised to
shortcut the reward sensor for maximum reward -- the so-called wireheading
problem. In this paper we suggest an alternative to RL called value
reinforcement learning (VRL). In VRL, agents use the reward signal to learn a
utility function. The VRL setup allows us to remove the incentive to wirehead
by placing a constraint on the agent's actions. The constraint is defined in
terms of the agent's belief distributions, and does not require an explicit
specification of which actions constitute wireheading.


title:
Low-power Mid-IR Supercontinuum and Rogue Wave Generation in
  Chalcogenide Waveguides

abstract:
  We present numerical results of supercontinuum (SC) generation in the mid-IR
spectral region, specifically addressing the molecular fingerprint window
ranging from 2.5 to 25 um. By solving the Generalized Nonlinear Schr\"odinger
Equation (GNLSE) in a chalcogenide waveguide, we demonstrate low-power SC
generation beyond 10 um from a pump at 5 um. Further, we investigate the
short-pulse and CW regimes, and show that a simple linear dispersion profile,
applicable to a broad range of chalcogenide media, is sufficient to account for
the broad SC generation, and yield rich pulse dynamics leading to the frequent
occurrence of rogue wave events. Results are encouraging as they point to the
feasibility of producing bright and coherent light, by means of single
low-power tabletop laser pumping schemes, in a spectral region that finds
applications in such diverse areas as molecular spectroscopy, metrology and
tomography, among others, and that is not easily addressable with other light
sources


title: Microscopic Friction Emulators

abstract:
  Cold ions sliding across periodic potential patterns formed by lasers
elucidate the physics of dry friction between crystals. Experiments with no
more than six ions suffice to explore a vast domain of frictional forces.


title:
Search for time-independent Lorentz violation using muon neutrino to
  muon antineutrino transitions in MINOS

abstract:
  Data from the MINOS experiment has been used to search for mixing between
muon neutrinos and muon antineutrinos using a time-independent
Lorentz-violating formalism derived from the Standard-Model Extension (SME).
MINOS is uniquely capable of searching for muon neutrino-antineutrino mixing
given its long baseline and ability to distinguish between neutrinos and
antineutrinos on an event-by-event basis. Neutrino and antineutrino
interactions were observed in the MINOS Near and Far Detectors from an exposure
of 10.56$\times10^{20}$ protons-on-target from the NuMI neutrino-optimized
beam. No evidence was found for such transitions and new, highly stringent
limits were placed on the SME coefficients governing them. We place the first
limits on the SME parameters $(c_{L})^{TT}_{\mu\mu} $ and
$(c_{L})^{TT}_{\tau\tau}$ at $-8.4\times10^{-23} < (c_{L})^{TT}_{\mu\mu} <
8.0\times10^{-23}$ and $-8.0\times10^{-23} < (c_{L})^{TT}_{\tau\tau} <
8.4\times10^{-23}$, and the world's best limits on the
$\tilde{g}^{ZT}_{\mu\overline{\mu}}$ and $\tilde{g}^{ZT}_{\tau\overline{\tau}}$
parameters at $|\tilde{g}^{ZT}_{\mu\overline{\mu}}| < 3.3\times 10^{-23}$ and
$|\tilde{g}^{ZT}_{\tau\overline{\tau}}| < 3.3\times 10^{-23}$, all limits
quoted at $3\sigma$.


title:
On abstract homomorphisms of Chevalley groups over the coordinate rings
  of affine curves

abstract:
  The goal of this paper is to establish a general rigidity statement for
abstract representations of elementary subgroups of Chevalley groups of rank at
least 2 over a class of commutative rings that includes the localizations of
1-generated rings and the coordinate rings of affine curves. This is achieved
by developing the approach introduced in our previous work, and in particular
by verifying condition (Z) over the class of rings at hand. Our main result
implies, for example, that any finite-dimensional representation of SL_n(Z[X])
(for n at least 3) over an algebraically closed field of characteristic 0 has a
standard description, yielding thereby the first unconditional rigidity
statement for finitely generated linear groups other than arithmetic
groups/lattices.


title: Coverage Embedding Models for Neural Machine Translation

abstract:
  In this paper, we enhance the attention-based neural machine translation
(NMT) by adding explicit coverage embedding models to alleviate issues of
repeating and dropping translations in NMT. For each source word, our model
starts with a full coverage embedding vector to track the coverage status, and
then keeps updating it with neural networks as the translation goes.
Experiments on the large-scale Chinese-to-English task show that our enhanced
model improves the translation quality significantly on various test sets over
the strong large vocabulary NMT system.


title: The complexity of downward closure comparisons

abstract:
  The downward closure of a language is the set of all (not necessarily
contiguous) subwords of its members. It is well-known that the downward closure
of every language is regular. Moreover, recent results show that downward
closures are computable for quite powerful system models.
  One advantage of abstracting a language by its downward closure is that then
equivalence and inclusion become decidable. In this work, we study the
complexity of these two problems. More precisely, we consider the following
decision problems: Given languages $K$ and $L$ from classes $\mathcal{C}$ and
$\mathcal{D}$, respectively, does the downward closure of $K$ include (equal)
that of $L$?
  These problems are investigated for finite automata, one-counter automata,
context-free grammars, and reversal-bounded counter automata. For each
combination, we prove a completeness result either for fixed or for arbitrary
alphabets. Moreover, for Petri net languages, we show that both problems are
Ackermann-hard and for higher-order pushdown automata of order~$k$, we prove
hardness for complements of nondeterministic $k$-fold exponential time.


title: Road Detection through Supervised Classification

abstract:
  Autonomous driving is a rapidly evolving technology. Autonomous vehicles are
capable of sensing their environment and navigating without human input through
sensory information such as radar, lidar, GNSS, vehicle odometry, and computer
vision. This sensory input provides a rich dataset that can be used in
combination with machine learning models to tackle multiple problems in
supervised settings. In this paper we focus on road detection through
gray-scale images as the sole sensory input. Our contributions are twofold:
first, we introduce an annotated dataset of urban roads for machine learning
tasks; second, we introduce a road detection framework on this dataset through
supervised classification and hand-crafted feature vectors.


title: Split Domination, Independence, and Irredundance in Graphs

abstract:
  In 1978, Kulli and Janakiram \citep{KulliJanakiramSplit} defined the split
dominating set: a dominating set $S$ of vertices in a graph $G = (V, E)$ is
called {\em split dominating} if the induced subgraph $\langle V \setminus
S\rangle$ is either disconnected or a $K_1$. In this paper we introduce the
properties split independence and split irredundance. A set $S$ of vertices in
a graph $G =(V,E)$ is called a {\em split independent set} if $S$ is
independent and the induced subgraph $\langle V \setminus S \rangle$ is either
disconnected or a $K_1$. A set $S$ of vertices in a graph $G = (V,E)$ is called
a {\em split irredundant set} if for $u \in S$, $u$ has a private neighbor with
respect to $V(S)$ and the induced subgraph $\langle V \setminus S\rangle$ is
either disconnected or a $K_1$.


title: Multiobjective Optimization in a Quantum Adiabatic Computer

abstract:
  In this work we present a quantum algorithm for multiobjective combinatorial
optimization. We show how to map a convex combination of objective functions
onto a Hamiltonian and then use that Hamiltonian to prove that the quantum
adiabatic algorithm of Farhi \emph{et al.} [arXiv:quant-ph/0001106] can find
Pareto-optimal solutions in finite time provided certain convex combinations of
objectives are used and the underlying multiobjective problem meets certain
restrictions.


title:
Wind Turbine Large-Eddy Simulations on Very Coarse Grid Resolutions
  using an Actuator Line Model

abstract:
  In this work the accuracy of the Actuator Line Model (ALM) in Large Eddy
Simulations of wind turbine flow is studied under the specific conditions of
very coarse spatial resolutions. For finely-resolved conditions, it is known
that ALM provides better accuracy compared to the standard Actuator Disk Model
(ADM) without rotation. However, we show here that on very coarse resolutions,
flow induction occurring at rotor scales can affect the predicted inflow angle
and can adversely affect the ALM predictions. We first provide an illustration
of coarse LES to reproduce wind tunnel measurements. The resulting flow
predictions are good, but the challenges in predicting power outputs from the
detailed ALM motivate more detailed analysis on a case with uniform inflow. We
present a theoretical framework to compare the filtered quantities that enter
the Large-Eddy Simulation equations as body forces with a scaling relation
between the filtered and unfiltered quantities. The study aims to apply the
theoretical derivation to the simulation framework and improve the current
results for an ALM, especially in the near wake where the largest differences
are observed.


title:
Two Stage Non-penalized Corrected Least Squares for High Dimensional
  Linear Models with Measurement error or Missing Covariates

abstract:
  This paper provides an alternative to penalized estimators for estimation and
vari- able selection in high dimensional linear regression models with
measurement error or missing covariates. We propose estimation via bias
corrected least squares after model selection. We show that by separating model
selection and estimation, it is possible to achieve an improved rate of
convergence of the L2 estimation error compared to the rate sqrt{s log p/n}
achieved by simultaneous estimation and variable selection methods such as L1
penalized corrected least squares. If the correct model is selected with high
probability then the L2 rate of convergence for the proposed method is indeed
the oracle rate of sqrt{s/n}. Here s, p are the number of non zero parameters
and the model dimension, respectively, and n is the sample size. Under very
general model selection criteria, the proposed method is computationally
simpler and statistically at least as efficient as the L1 penalized corrected
least squares method, performs model selection without the availability of the
bias correction matrix, and is able to provide estimates with only a small
sub-block of the bias correction covariance matrix of order s x s in comparison
to the p x p correction matrix required for computation of the L1 penalized
version. Furthermore we show that the model selection requirements are met by a
correlation screening type method and the L1 penalized corrected least squares
method. Also, the proposed methodology when applied to the estimation of
precision matrices with missing observations, is seen to perform at least as
well as existing L1 penalty based methods. All results are supported
empirically by a simulation study.


title: A partial differential equation for the rank one convex envelope

abstract:
  In this article we introduce a Partial Differential Equation (PDE) for the
rank one convex envelope. Rank one convex envelopes arise in non-convex vector
valued variational problems \cite{BallElasticity, kohn1986optimal1,
BallJames87, chipot1988equilibrium}. More generally, we study a PDE for
directional convex envelopes, which includes the usual convex envelope
\cite{ObermanConvexEnvelope} and the rank one convex envelope as special cases.
Existence and uniqueness of viscosity solutions to the PDE is established. Wide
stencil elliptic finite difference schemes are built. Convergence of finite
difference solutions to the viscosity solution of the PDE is proven. Numerical
examples of rank one and other directional convex envelopes are presented.
Additionally, laminates are computed from the rank one convex envelope.


title:
Assessing lepton-flavour non-universality from $B\to K^*\ell\ell$
  angular analyses

abstract:
  The $B\to K^*\mu\mu$ decay exhibits deviations with respect to Standard Model
expectations and the measurement of the ratio $R_K$ hints at a violation of
lepton-flavour universality in $B\to K\ell\ell$ transitions. Both effects can
be understood in model-independent fits as a short-distance contribution to the
Wilson coefficient $C_{9\mu}$, with some room for similar contributions in
other Wilson coefficients for $b\to s\mu\mu$ transitions. We discuss how a full
angular analysis of $B\to K^*ee$ and its comparison with $B\to K^*\mu\mu$ could
improve our understanding of these anomalies and help confirming their
interpretation in terms of short-distance New Physics. We discuss several
observables of interest in this context and provide predictions for them within
the Standard Model as well as within several New Physics benchmark scenarios.
We pay special attention to the sensitivity of these observables to hadronic
uncertainties from SM contributions with charm loops.


title: Adaptive Integrand Decomposition in parallel and orthogonal space

abstract:
  We present the integrand decomposition of multiloop scattering amplitudes in
parallel and orthogonal space-time dimensions, $d=d_\parallel+d_\perp$, being
$d_\parallel$ the dimension of the parallel space spanned by the legs of the
diagrams. When the number $n$ of external legs is $n\le 4$, the corresponding
representation of the multiloop integrals exposes a subset of integration
variables which can be easily integrated away by means of Gegenbauer
polynomials orthogonality condition. By decomposing the integration momenta
along parallel and orthogonal directions, the polynomial division algorithm is
drastically simplified. Moreover, the orthogonality conditions of Gegenbauer
polynomials can be suitably applied to integrate the decomposed integrand,
yielding the systematic annihilation of spurious terms. Consequently, multiloop
amplitudes are expressed in terms of integrals corresponding to irreducible
scalar products of loop momenta and external momenta. We revisit the one-loop
decomposition, which turns out to be controlled by the maximum-cut theorem in
different dimensions, and we discuss the integrand reduction of two-loop planar
and non-planar integrals up to $n=8$ legs, for arbitrary external and internal
kinematics. The proposed algorithm extends to all orders in perturbation
theory.


title: Transiently Consistent SDN Updates: Being Greedy is Hard

abstract:
  The software-defined networking paradigm introduces interesting opportunities
to operate networks in a more flexible, optimized, yet formally verifiable
manner. Despite the logically centralized control, however, a Software-Defined
Network (SDN) is still a distributed system, with inherent delays between the
switches and the controller. Especially the problem of changing network
configurations in a consistent manner, also known as the consistent network
update problem, has received much attention over the last years. In particular,
it has been shown that there exists an inherent tradeoff between update
consistency and speed. This paper revisits the problem of updating an SDN in a
transiently consistent, loop-free manner. First, we rigorously prove that
computing a maximum (greedy) loop-free network update is generally NP-hard;
this result has implications for the classic maximum acyclic subgraph problem
(the dual feedback arc set problem) as well. Second, we show that for special
problem instances, fast and good approximation algorithms exist.


title: The masses of the neutrinos

abstract:
  If the cosmological limits on the sum of the neutrino masses are taken
seriously we have first measurements of the masses of the neutrinos. Using the
Planck experiment's limit $\sum_{i=1}^3{m_i} < 230 ~meV$ and some simple
assumptions on measurement uncertainties the mass of the heaviest neutrino is
$63\pm11 ~meV$ and the lightest $40\pm18 ~meV$ for either hierarchy.


title: Decoherence of rotational degrees of freedom

abstract:
  The mechanism of decoherence for a quantum system with rotational degrees of
freedom is studied. From a simple model of elastic scattering, we show that the
non-diagonal density matrix elements of the system exponentially decay. The
decay rate depends on the difference of scattering amplitudes for different
rotational configurations, leading to the gradual loss of quantum coherence
between the pointer states in the system orientational space. For a dielectric
ellipsoid immersed in a photon-gas environment (assuming no absorption), the
decay rate is found to be proportional to the seventh power of the temperature.
For an ellipsoidal object interacting with mass particles, the decay rate is
proportional to the 5/2 power of the temperature. Both are different from the
case of translational decoherence induced by the same environment scattering.
For photon scattering, the coherence time in the rotational degrees of freedom
is shown to be much shorter than that in the translational degrees of freedom.


title:
The Environment of z >1 3CR Radio Galaxies and QSOs: From Proto-Clusters
  to Clusters of Galaxies?

abstract:
  We study the cluster environment for a sample of 21 radio loud AGN from the
3CR catalog at z>1, 12 radio galaxies and 9 quasars with HST images in the
optical and IR. We use two different approaches to determine cluster
candidates. We identify the early type galaxies (ETGs) in every field by
modeling each of the sources within a 40" radius of the targets with a Sersic
profile. Using a simple passive evolution model, we derive the expected
location of the ETGs on the red sequence (RS) in the color-magnitude diagram
for each of the fields of our sources. For seven targets, the model coincides
with the position of the ETGs. A second approach involves a search for over
densities. We compare the object densities of the sample as a whole and
individually against control fields taken from the GOODS-S region of 3D-HST
survey. With this method we determine the fields of 10 targets to be cluster
candidates. Four cluster candidates are found by both methods. The two methods
disagree in some cases, depending on the specific properties of each field. For
the most distant radio galaxy in the 3CR catalog (3C257 at z = 2.47), we
identify a population of bluer ETGs that lie on the expected location of the RS
model for that redshift. This appears to be the general behavior of ETGs in our
fields and it is possibly a signature of the evolution of such galaxies. Our
results are consistent with half of the z > 1 radio galaxies being located in
dense, rapidly evolving environments.


title:
Dead Letters to Alice - Reachability of E-Mail Addresses in the PGP Web
  of Trust

abstract:
  Over the last 25 years four million e-mail addresses have accumulated in the
PGP web of trust. In a study each of them was tested for vitality with the
result of 40% being unreachable. Of the mailboxes proven to be reachable,
46.77% turn out to be operated by one of three organizations. In this article,
the authors share their results and challenges during the study.


title: Measurement of Laterally Induced Optical Forces at the Nanoscale

abstract:
  We demonstrate the measurement of laterally induced optical forces using an
Atomic Force Microscope (AFM). The lateral electric field distribution between
a gold coated AFM probe and a nano-aperture in a gold film is mapped by
measuring the lateral optical force between the apex of the AFM probe and the
nano-aperture. Torsional eigenmodes of an AFM cantilever probe were used to
detect the laterally induced optical forces. We engineered the cantilever shape
using a focused ion beam to enhance the torsional eigenmode resonance. The
measured lateral optical force agrees well with simulations. This technique can
be extended to simultaneously detect both lateral and longitudinal optical
forces at the nanoscale by using an AFM cantilever as a multichannel detector.
This will enable simultaneous Photon Induced Force Microscopy (PIFM) detection
of molecular responses with different incident field polarizations. The
technique can be implemented on both cantilever and tuning fork based AFMs.


title:
Compressing turbulence and sudden viscous dissipation with
  compression-dependent ionization state

abstract:
  Turbulent plasma flow, amplified by rapid 3D compression, can be suddenly
dissipated under continuing compression. This effect relies on the sensitivity
of the plasma viscosity to the temperature, $\mu \sim T^{5/2}$. The plasma
viscosity is also sensitive to the plasma ionization state. We show that the
sudden dissipation phenomenon may be prevented when the plasma ionization state
increases during compression, and demonstrate the regime of net viscosity
dependence on compression where sudden dissipation is guaranteed. Additionally,
it is shown that, compared to cases with no ionization, ionization during
compression is associated with larger increases in turbulent energy, and can
make the difference between growing and decreasing turbulent energy.


title: Twistor Parametrization of Locally BPS Super-Wilson Loops

abstract:
  We consider the kinematics of the locally BPS super-Wilson loop in
$\mathcal{N}=4$ super-Yang-Mills with scalar coupling from a twistorial point
of view. We find that the kinematics can be described either as
supersymmetrized pure spinors or as a point in $G_{2\vert 2}(4\vert 4) \times
G_{2\vert 2}(4\vert 4)$. In this description of the kinematics the
scalar--scalar correlation function appearing in the one-loop evaluation of the
super-Wilson loop can be neatly written as a sum of four super-determinants.


title:
On the Relation between the Mysterious 21 Micrometer Emission Feature of
  Post-Asymptotic Giant Branch Stars and Their Mass Loss Rates

abstract:
  Over two decades ago, a prominent, mysterious emission band peaking at ~20.1
micrometer was serendipitously detected in four preplanetary nebulae (PPNe;
also known as "protoplanetary nebulae"). So far, this spectral feature,
designated as the "21 micrometer" feature, has been seen in 18 carbon-rich
PPNe. The nature of the carriers of this feature remains unknown although many
candidate materials have been proposed. The 21 micrometer sources also exhibit
an equally mysterious, unidentified emission feature peaking at 30 micrometer.
While the 21 micrometer feature is exclusively seen in PPNe, a short-lived
evolutionary stage between the end of the asymptotic giant branch (AGB) and
planetary nebula (PN) phases, the 30 micrometer feature is commonly observed in
all stages of stellar evolution from the AGB through PPN to PNe phases. We
derive the stellar mass loss rates (M_{loss}) of these 21 micrometer sources
from their dust infrared (IR) emission, using the "2-DUST" radiative transfer
code for axisymmetric dusty systems which allows one to distinguish the mass
loss rates of the AGB phase (\dot{M_{AGB}}) from that of the superwind
(\dot_{M_{SW}}) phase. We examine the correlation between \dot{M_{AGB}} or
\dot_{M_{SW}} and the fluxes emitted from the 21 and 30 micrometer features. We
find that both features tend to correlate with \dot{M_{AGB}}, suggesting that
their carriers are probably formed in the AGB phase. The nondetection of the 21
micrometer feature in AGB stars suggests that, unlike the 30 micrometer
feature, the excitation of the carriers of the 21 micrometer feature may
require ultraviolet photons which are available in PPNe but not in AGB stars.


title:
A new family of analytic functions defined by means of Rodrigues type
  formula

abstract:
  In this article, a class of analytic functions is investigated and their some
properties are established. Several recurrence relations and various classes of
bilinear and bilateral generating functions for these analytic functions are
also derived. Examples of some members belonging to this family of analytic
functions are given and differential equations satisfied by these functions are
also obtained.


title: Kolyvagin systems and Iwasawa theory of generalized Heegner cycles

abstract:
  Iwasawa theory of Heegner points on abelian varieties of GL_2 type has been
studied by, among others, Mazur, Perrin-Riou, Bertolini and Howard. The purpose
of this paper is to describe extensions of some of their results in which
abelian varieties are replaced by the Galois cohomology of Deligne's p-adic
representation attached to a modular form of even weight >2. In this setting,
the role of Heegner points is played by higher-dimensional Heegner-type cycles
that have been recently defined by Bertolini, Darmon and Prasanna. Our results
should be compared with those obtained, via deformation-theoretic techniques,
by Fouquet in the context of Hida families of modular forms.


title: Ballistic quench-induced correlation waves in ultracold gases

abstract:
  We investigate the wave packet dynamics of a pair of particles that undergoes
a rapid change of scattering length. The short-range interactions are modeled
in the zero-range limit, where the quench is accomplished by switching the
boundary condition of the wave function at vanishing particle separation. This
generates a correlation wave that propagates rapidly to nonzero particle
separations. We have derived universal, analytic results for this process that
lead to a simple phase-space picture of the quench-induced scattering.
Intuitively, the strength of the correlation wave relates to the initial
contact of the system. We find that, in one spatial dimension, the $k^{-4}$
tail of the momentum distribution contains a ballistic contribution that does
not originate from short-range pair correlations, and a similar conclusion can
hold in other dimensionalities depending on the quench protocol. We examine the
resultant quench-induced transport in an optical lattice in 1D, and a
semiclassical treatment is found to give quantitatively accurate estimates for
the transport probabilities.


title:
DeeperCut: A Deeper, Stronger, and Faster Multi-Person Pose Estimation
  Model

abstract:
  The goal of this paper is to advance the state-of-the-art of articulated pose
estimation in scenes with multiple people. To that end we contribute on three
fronts. We propose (1) improved body part detectors that generate effective
bottom-up proposals for body parts; (2) novel image-conditioned pairwise terms
that allow to assemble the proposals into a variable number of consistent body
part configurations; and (3) an incremental optimization strategy that explores
the search space more efficiently thus leading both to better performance and
significant speed-up factors. Evaluation is done on two single-person and two
multi-person pose estimation benchmarks. The proposed approach significantly
outperforms best known multi-person pose estimation results while demonstrating
competitive performance on the task of single person pose estimation. Models
and code available at http://pose.mpi-inf.mpg.de


title:
Search for new physics in same-sign dilepton events in proton-proton
  collisions at sqrt(s) = 13 TeV

abstract:
  A search for new physics is performed using events with two isolated
same-sign leptons, two or more jets, and missing transverse momentum. The
results are based on a sample of proton-proton collisions at a center-of-mass
energy of 13 TeV recorded with the CMS detector at the LHC, corresponding to an
integrated luminosity of 2.3 inverse femtobarns. Multiple search regions are
defined by classifying events in terms of missing transverse momentum, the
scalar sum of jet transverse momenta, the transverse mass associated with a W
boson candidate, the number of jets, the number of b quark jets, and the
transverse momenta of the leptons in the event. The analysis is sensitive to a
wide variety of possible signals beyond the standard model. No excess above the
standard model background expectation is observed. Constraints are set on
various supersymmetric models, with gluinos and bottom squarks excluded for
masses up to 1300 and 680 GeV, respectively, at the 95% confidence level. Upper
limits on the cross sections for the production of two top quark-antiquark
pairs (119 fb) and two same-sign top quarks (1.7 pb) are also obtained.
Selection efficiencies and model independent limits are provided to allow
further interpretations of the results.


title:
The number of subsets of integers with no $k$-term arithmetic
  progression

abstract:
  Addressing a question of Cameron and Erd\Ho s, we show that, for infinitely
many values of $n$, the number of subsets of $\{1,2,\ldots, n\}$ that do not
contain a $k$-term arithmetic progression is at most $2^{O(r_k(n))}$, where
$r_k(n)$ is the maximum cardinality of a subset of $\{1,2,\ldots, n\}$ without
a $k$-term arithmetic progression. This bound is optimal up to a constant
factor in the exponent. For all values of $n$, we prove a weaker bound, which
is nevertheless sufficient to transfer the current best upper bound on $r_k(n)$
to the sparse random setting. To achieve these bounds, we establish a new
supersaturation result, which roughly states that sets of size $\Theta(r_k(n))$
contain superlinearly many $k$-term arithmetic progressions.
  For integers $r$ and $k$, Erd\Ho s asked whether there is a set of integers
$S$ with no $(k+1)$-term arithmetic progression, but such that any $r$-coloring
of $S$ yields a monochromatic $k$-term arithmetic progression. Ne\v{s}et\v{r}il
and R\"odl, and independently Spencer, answered this question affirmatively. We
show the following density version: for every $k\ge 3$ and $\delta>0$, there
exists a reasonably dense subset of primes $S$ with no $(k+1)$-term arithmetic
progression, yet every $U\subseteq S$ of size $|U|\ge\delta|S|$ contains a
$k$-term arithmetic progression.
  Our proof uses the hypergraph container method, which has proven to be a very
powerful tool in extremal combinatorics. The idea behind the container method
is to have a small certificate set to describe a large independent set. We give
two further applications in the appendix using this idea.


title: Integrable strings for AdS/CFT

abstract:
  In this PhD thesis we review some aspects of integrable models related to
string backgrounds or their deformations. In the first part we develop methods
to obtain exact results in the AdS3/CFT2 correspondence. We consider the AdS_3
x S^3 x T^4 background with pure Ramond-Ramond flux and we find the all-loop
worldsheet S-matrix by exploiting the symmetries of the model in light-cone
gauge. As we naturally include the massless modes on the worldsheet, we derive
the full set of Bethe-Yang equations. In the massive sector we give also a
spin-chain description and we write down solutions compatible with crossing for
the scalar factors which are not constrained by simmetries. In the second part
of the thesis we consider the so-called "eta-deformation" of the superstring on
AdS_5 x S^5. We first discuss the effects of the deformation at the level of
the bosonic sigma-model, and we match the tree-level worldsheet scattering
processes to the expansion of the q-deformed S-matrix. To identify the missing
Ramond-Ramond fields we then compute the action quadratic in fermions, and we
provide an alternative derivation by looking at the kappa-symmetry variations.
The resulting background fields do not solve the equations of motion of type
IIB supergravity and we comment on this.


title: A study of the wiggle morphology of HH 211 through numerical simulations

abstract:
  Recent high-resolution high-sensitivity observations of protostellar jets
have shown many to possess deviations to their trajectories. HH 211 is one such
example where sub-mm observations with the SMA have revealed a clear
reflection-symmetric wiggle. The most likely explanation is that the HH 211 jet
source could be moving as part of a protobinary system. Here we test this
assumption by simulating HH 211 through 3D hydrodynamic jet propagation
simulations using the PLUTO code with a molecular chemistry and cooling module,
and initial conditions based on an analytical model derived from SMA
observations. Our results show the reflection-symmetric wiggle can be recreated
through the assumption of a jet source perturbed by binary motion at its base,
and that a regular sinusoidal velocity variation in the jet beam can be close
to matching the observed knot pattern. However, a more complex model with
either additional heating from the protostar, or a shorter period velocity
pulsation may be required to account for enhanced emission near the source, and
weaker knot emission downstream. Position velocity diagrams along the pulsed
jet beam show a complex structure with detectable signatures of knots and show
caution must be exercised when interpreting radial velocity profiles through
observations. Finally, we make predictions for future HH 211 observations with
ALMA.


title:
Towards a Technique for Extracting Microservices from Monolithic
  Enterprise Systems

abstract:
  The idea behind microservices architecture is to develop a single large,
complex application as a suite of small, cohesive, independent services. On the
other way, monolithic systems get larger over the time, deviating from the
intended architecture, and becoming risky and expensive to evolve. This paper
describes a technique to identify and define microservices on monolithic
enterprise systems. As the major contribution, our evaluation shows that our
approach was able to identify relevant candidates to become microservices on a
750 KLOC banking system.


title: Wave diffraction by a cosmic string

abstract:
  We show that if a cosmic string exists, it may be identified through
characteristic diffraction pattern in the energy spectrum of the observed
signal. In particular, if the string is on the line of sight, the wave field is
shown to fit the Cornu spiral. We suggest a simple procedure, based on Keller's
geometrical theory of diffraction, which allows to explain wave effects in
conical spacetime of a cosmic string in terms of interference of four
characteristic rays. Our results are supposed to be valid for scalar massless
waves, including gravitational waves, electromagnetic waves, or even sound in
case of condensed matter systems with analogous topological defects.


title: Engineering topological materials in microwave cavity arrays

abstract:
  We present a scalable architecture for the exploration of interacting
topological phases of photons in arrays of microwave cavities, using
established techniques from cavity and circuit quantum electrodynamics. A
time-reversal symmetry breaking (non-reciprocal) flux is induced by coupling
the microwave cavities to ferrites, allowing for the production of a variety of
topological band structures including the $\alpha=1/4$ Hofstadter model.
Effective photon-photon interactions are included by coupling the cavities to
superconducting qubits, and are sufficient to produce a $\nu=1/2$ bosonic
Laughlin puddle. We demonstrate by exact diagonalization that this architecture
is robust to experimentally achievable levels of disorder. These advances
provide an exciting opportunity to employ the quantum circuit toolkit for the
exploration of strongly interacting topological materials.

categories: cond-mat.quant-gas cond-mat.mes-hall physics.optics quant-ph


title: Solving the Wrong Hierarchy Problem

abstract:
  Many theories require augmenting the Standard Model with additional scalar
fields with large order one couplings. We present a new solution to the
hierarchy problem for these scalar fields. We explore parity- and
$\mathbb{Z}_2$-symmetric theories where the Standard Model Higgs potential has
two vacua. The parity or $\mathbb{Z}_2$ copy of the Higgs lives in the minimum
far from the origin while our Higgs occupies the minimum near the origin of the
potential. This approach results in a theory with multiple light scalar fields
but with only a single hierarchy problem, since the bare mass is tied to the
Higgs mass by a discrete symmetry. The new scalar does not have a new hierarchy
problem associated with it because its expectation value and mass are generated
by dimensional transmutation of the scalar quartic coupling. The location of
the second Higgs minimum is not a free parameter, but is rather a function of
the matter content of the theory. As a result, these theories are extremely
predictive. We develop this idea in the context of a solution to the strong CP
problem. We show this mechanism postdicts the top Yukawa to be within $1
\sigma$ of the currently measured value and predicts scalar color octets with
masses in the range 9-200 TeV.


title: Reionisation in sterile neutrino cosmologies

abstract:
  We investigate the process of reionisation in a model in which the dark
matter is a warm elementary particle such as a sterile neutrino. We focus on
models that are consistent with the dark matter decay interpretation of the
recently detected line at 3.5 keV in the X-ray spectra of galaxies and
clusters. In warm dark matter models the primordial spectrum of density
perturbations has a cut-off on the scale of dwarf galaxies. Structure formation
therefore begins later than in the standard cold dark matter (CDM) model and
very few objects form below the cut-off mass scale. To calculate the number of
ionising photons, we use the Durham semi-analytic model of galaxy formation,
GALFORM. We find that even the most extreme 7 keV sterile neutrino we consider
is able to reionise the Universe early enough to be compatible with the bounds
on the epoch of reionisation from Planck. This, perhaps surprising, result
arises from the rapid build-up of high redshift galaxies in the sterile
neutrino models which is also reflected in a faster evolution of their far-UV
luminosity function between $10>z>7$ than in CDM. The dominant sources of
ionising photons are systematically more massive in the sterile neutrino models
than in CDM. As a consistency check on the models, we calculate the present-day
luminosity function of satellites of Milky Way-like galaxies. When the
satellites recently discovered in the DES survey are taken into account, strong
constraints are placed on viable sterile neutrino models.


title:
The Ionized Gas in Nearby Galaxies as Traced by the [NII] 122 and 205
  \mu m Transitions

abstract:
  The [NII] 122 and 205 \mu m transitions are powerful tracers of the ionized
gas in the interstellar medium. By combining data from 21 galaxies selected
from the Herschel KINGFISH and Beyond the Peak surveys, we have compiled 141
spatially resolved regions with a typical size of ~1 kiloparsec, with
observations of both [NII] far-infrared lines. We measure [NII] 122/205 line
ratios in the ~0.6-6 range, which corresponds to electron gas densities
$n_e$~1-300 cm$^{-3}$, with a median value of $n_e$=30 cm$^{-3}$. Variations in
the electron density within individual galaxies can be as a high as a factor of
~50, frequently with strong radial gradients. We find that $n_e$ increases as a
function of infrared color, dust-weighted mean starlight intensity, and star
formation rate surface density ($\Sigma_{SFR}$). As the intensity of the [NII]
transitions is related to the ionizing photon flux, we investigate their
reliability as tracers of the star formation rate (SFR). We derive relations
between the [NII] emission and SFR in the low-density limit and in the case of
a log-normal distribution of densities. The scatter in the correlation between
[NII] surface brightness and $\Sigma_{SFR}$ can be understood as a property of
the $n_e$ distribution. For regions with $n_e$ close to or higher than the
[NII] line critical densities, the low-density limit [NII]-based SFR
calibration systematically underestimates the SFR since [NII] emission is
collisionally quenched. Finally, we investigate the relation between [NII]
emission, SFR, and $n_e$ by comparing our observations to predictions from the
MAPPINGS-III code.


title: QCDLoop: a comprehensive framework for one-loop scalar integrals

abstract:
  We present a new release of the QCDLoop library based on a modern
object-oriented framework. We discuss the available new features such as the
extension to the complex masses, the possibility to perform computations in
double and quadruple precision simultaneously, and useful caching mechanisms to
improve the computational speed. We benchmark the performance of the new
library, and provide practical examples of phenomenological implementations by
interfacing this new library to Monte Carlo programs.


title:
Effects of Local Environment and Stellar Mass on Galaxy Quenching out to
  z~3

abstract:
  We study the effects of local environment and stellar mass on galaxy
properties using a mass complete sample of quiescent and star-forming systems
in the COSMOS field at $z\lesssim$ 3. We show that at $z\lesssim$ 1, the median
star-formation rate (SFR) and specific SFR (sSFR) of all galaxies depend on
environment, but they become independent of environment at $z\gtrsim$ 1.
However, we find that only for \textit{star-forming} galaxies, the median SFR
and sSFR are similar in different environments, regardless of redshift and
stellar mass. We find that the quiescent fraction depends on environment at
$z\lesssim$ 1, and on stellar mass out to $z\sim$ 3. We show that at
$z\lesssim$ 1, galaxies become quiescent faster in denser environments and that
the overall environmental quenching efficiency increases with cosmic time.
Environmental and mass quenching processes depend on each other. At $z\lesssim$
1, denser environments more efficiently quench galaxies with higher masses
(log($M/M_{\odot}$)$\gtrsim$ 10.7), possibly due to a higher merger rate of
massive galaxies in denser environments, and that mass quenching is more
efficient in denser regions. We show that the overall mass quenching efficiency
($\epsilon_{mass}$) for more massive galaxies (log($M/M_{\odot}$)$\gtrsim$
10.2) rises with cosmic time until $z\sim$ 1 and flattens out since then.
However, for less massive galaxies, the rise in $\epsilon_{mass}$ continues to
the present time. Our results suggest that environmental quenching is only
relevant at $z\lesssim$ 1, likely a fast process, whereas mass quenching is the
dominant mechanism at $z\gtrsim$ 1, with a possible stellar feedback physics.


title:
Cosmic Reionization On Computers. Properties of the Post-reionization
  IGM

abstract:
  We present a comparison between several observational tests of the
post-reionization IGM and the numerical simulations of reionization completed
under the Cosmic Reionization On Computers (CROC) project. The CROC simulations
match the gap distribution reasonably well, and also provide a good match for
the distribution of peak heights, but there is a notable lack of wide peaks in
the simulated spectra and the flux PDFs are poorly matched in the narrow
redshift interval 5.5<z<5.7, with the match at other redshifts being
significantly better, albeit not exact. Both discrepancies are related:
simulations show more opacity than the data.


title:
Radiative, two-temperature simulations of low luminosity black hole
  accretion flows in general relativity

abstract:
  We present a numerical method which evolves a two-temperature, magnetized,
radiative, accretion flow around a black hole, within the framework of general
relativistic radiation magnetohydrodynamics. As implemented in the code KORAL,
the gas consists of two sub-components -- ions and electrons -- which share the
same dynamics but experience independent, relativistically consistent,
thermodynamical evolution. The electrons and ions are heated independently
according to a standard prescription from the literature for
magnetohydrodynamical turbulent dissipation. Energy exchange between the
particle species via Coulomb collisions is included. In addition, electrons
gain and lose energy and momentum by absorbing and emitting synchrotron and
bremsstrahlung radiation, and through Compton scattering. All evolution
equations are handled within a fully covariant framework in the relativistic
fixed-metric spacetime of the black hole. Numerical results are presented for
five models of low luminosity black hole accretion. In the case of a model with
a mass accretion rate $\dot{M}\sim10^{-8} \dot M_{\rm Edd}$, we find that
radiation has a negligible effect on either the dynamics or the thermodynamics
of the accreting gas. In contrast, a model with a larger $\dot{M}\sim 4\times
10^{-4} \dot M_{\rm Edd}$ behaves very differently. The accreting gas is much
cooler and the flow is geometrically less thick, though it is not quite a thin
accretion disk.


title:
Simulating the timescale dependent color variation in quasars with a
  revised inhomogeneous disk model

abstract:
  The UV/optical variability of active galactic nuclei and quasars is useful
for understanding the physics of the accretion disk and is gradually attributed
to the stochastic fluctuations over the accretion disk. Quasars generally
appear bluer when they brighten in the UV/optical, the nature of which remains
controversial. Recently \citeauthor{Sun2014} discovered that the color
variation of quasars is timescale dependent, in the way that faster variations
are even bluer than longer term ones. While this discovery can directly rule
out models that simply attribute the color variation to contamination from the
host galaxies, or to changes in the global accretion rates, it favors the
stochastic disk fluctuation model as fluctuations in the innermost hotter disk
could dominate the short-term variations. In this work, we show that a revised
inhomogeneous disk model, where the characteristic timescales of thermal
fluctuations in the disk are radius-dependent (i.e., $\tau \sim r$; based on
the one originally proposed by \citeauthor{DexterAgol2011}), can well reproduce
a timescale dependent color variation pattern, similar to the observed one and
unaffected by the un-even sampling and photometric error. This demonstrates
that one may statistically use variation emission at different timescales to
spatially resolve the accretion disk in quasars, thus opens a new window to
probe and test the accretion disk physics in the era of time domain astronomy.
Caveats of the current model, which ought to be addressed in future
simulations, are discussed.