title: Classical and Quantum Mechanical Motion in Magnetic Fields

abstract:
  We study the motion of a particle in a particular magnetic field
configuration both classically and quantum mechanically. For flux-free radially
symmetric magnetic fields defined on circular regions, we establish that
particle escape speeds depend, classically, on a gauge-fixed magnetic vector
potential, and demonstrate some trajectories associated with this special type
of magnetic field. Then we show that some of the geometric features of the
classical trajectory (perpendicular exit from the field region, trapped and
escape behavior) are reproduced quantum mechanically using a numerical method
that extends the norm-preserving Crank-Nicolson method to problems involving
magnetic fields. While there are similarities between the classical trajectory
and the position expectation value of the quantum mechanical solution, there
are also differences, and we demonstrate some of these.


title:
Exact Bounded Boundary Controllability to Rest for the Two-Dimensional
  Wave Equation

abstract:
  The problem of the exact bounded control of oscillations of the
two-dimensional wave equation is considered. Control force is applied to the
boundary of the membrane, which is located in a domain on a plane. The goal of
the control is to drive the system to rest in a finite time.


title: Optimal Rebuilding of Multiple Erasures in MDS Codes

abstract:
  MDS array codes are widely used in storage systems due to their
computationally efficient encoding and decoding procedures. An MDS code with
$r$ redundancy nodes can correct any $r$ node erasures by accessing all the
remaining information in the surviving nodes. However, in practice, $e$
erasures is a more likely failure event, for $1\le e<r$. Hence, a natural
question is how much information do we need to access in order to rebuild $e$
storage nodes? We define the rebuilding ratio as the fraction of remaining
information accessed during the rebuilding of $e$ erasures. In our previous
work we constructed MDS codes, called zigzag codes, that achieve the optimal
rebuilding ratio of $1/r$ for the rebuilding of any systematic node when $e=1$,
however, all the information needs to be accessed for the rebuilding of the
parity node erasure.
  The (normalized) repair bandwidth is defined as the fraction of information
transmitted from the remaining nodes during the rebuilding process. For codes
that are not necessarily MDS, Dimakis et al. proposed the regenerating codes
framework where any $r$ erasures can be corrected by accessing some of the
remaining information, and any $e=1$ erasure can be rebuilt from some subsets
of surviving nodes with optimal repair bandwidth.
  In this work, we study 3 questions on rebuilding of codes: (i) We show a
fundamental trade-off between the storage size of the node and the repair
bandwidth similar to the regenerating codes framework, and show that zigzag
codes achieve the optimal rebuilding ratio of $e/r$ for MDS codes, for any
$1\le e\le r$. (ii) We construct systematic codes that achieve optimal
rebuilding ratio of $1/r$, for any systematic or parity node erasure. (iii) We
present error correction algorithms for zigzag codes, and in particular
demonstrate how these codes can be corrected beyond their minimum Hamming
distances.


title: Network modularity in the presence of covariates

abstract:
  We characterize the large-sample properties of network modularity in the
presence of covariates, under a natural and flexible nonparametric null model.
This provides for the first time an objective measure of whether or not a
particular value of modularity is meaningful. In particular, our results
quantify the strength of the relation between observed community structure and
the interactions in a network. Our technical contribution is to provide limit
theorems for modularity when a community assignment is given by nodal features
or covariates. These theorems hold for a broad class of network models over a
range of sparsity regimes, as well as weighted, multi-edge, and power-law
networks. This allows us to assign $p$-values to observed community structure,
which we validate using several benchmark examples in the literature. We
conclude by applying this methodology to investigate a multi-edge network of
corporate email interactions.


title: Remarks on Frankl's conjecture

abstract:
  First a few reformulations of Frankl's conjecture are given, in terms of
reduced families or matrices, or analogously in terms of lattices. These lead
naturally to a stronger conjecture with a neat formulation which might be
easier to attack than Frankl's. To this end we prove an inequality which might
help in proving the stronger conjecture.


title:
Characterizing the reproduction number of epidemics with early
  sub-exponential growth dynamics

abstract:
  Early estimates of the transmission potential of emerging and re-emerging
infections are increasingly used to inform public health authorities on the
level of risk posed by outbreaks. Existing methods to estimate the reproduction
number generally assume exponential growth in case incidence in the first few
disease generations, before susceptible depletion sets in. In reality,
outbreaks can display sub-exponential (i.e., polynomial) growth in the first
few disease generations, owing to clustering in contact patterns, spatial
effects, inhomogeneous mixing, reactive behavior changes, or other mechanisms.
Here, we introduce the generalized growth model to characterize the early
growth profile of outbreaks and estimate the effective reproduction number,
with no need for explicit assumptions about the shape of epidemic growth. We
demonstrate this phenomenologic approach using analytical results and
simulations from mechanistic models, and provide validation against a range of
empirical disease datasets. Our results suggest that sub-exponential growth in
the early phase of an epidemic is the rule rather the exception. For empirical
outbreaks, the generalized-growth model consistently outperforms the
exponential model for a variety of directly and indirectly transmitted diseases
datasets with model estimates supporting sub-exponential growth dynamics. The
rapid decline in effective reproduction number predicted by analytical results
and observed in real and synthetic datasets within 3-5 disease generations
contrasts with the expectation of invariant reproduction number in epidemics
obeying exponential growth. Overall, our approach promotes a more reliable and
data-driven characterization of the early epidemic phase, which is important
for accurate estimation of the reproduction number and prediction of disease
impact.


title:
Rate Splitting for MIMO Wireless Networks: A Promising PHY-Layer
  Strategy for LTE Evolution

abstract:
  MIMO processing plays a central part towards the recent increase in spectral
and energy efficiencies of wireless networks. MIMO has grown beyond the
original point-to-point channel and nowadays refers to a diverse range of
centralized and distributed deployments. The fundamental bottleneck towards
enormous spectral and energy efficiency benefits in multiuser MIMO networks
lies in a huge demand for accurate channel state information at the transmitter
(CSIT). This has become increasingly difficult to satisfy due to the increasing
number of antennas and access points in next generation wireless networks
relying on dense heterogeneous networks and transmitters equipped with a large
number of antennas. CSIT inaccuracy results in a multi-user interference
problem that is the primary bottleneck of MIMO wireless networks. Looking
backward, the problem has been to strive to apply techniques designed for
perfect CSIT to scenarios with imperfect CSIT. In this paper, we depart from
this conventional approach and introduce the readers to a promising strategy
based on rate-splitting. Rate-splitting relies on the transmission of common
and private messages and is shown to provide significant benefits in terms of
spectral and energy efficiencies, reliability and CSI feedback overhead
reduction over conventional strategies used in LTE-A and exclusively relying on
private message transmissions. Open problems, impact on standard specifications
and operational challenges are also discussed.


title:
Forcings and Feedbacks on Convection in the 2010 Pakistan Flood:
  Modeling Extreme Precipitation with Interactive Large-Scale Ascent

abstract:
  Extratropical extreme precipitation events are usually associated with
large-scale flow disturbances, strong ascent and large latent heat release. The
causal relationships between these factors are often not obvious, however, and
the roles of different physical processes in producing the extreme
precipitation event can be difficult to disentangle. Here, we examine the
large-scale forcings and convective heating feedback in the precipitation
events which caused the 2010 Pakistan flood within the Column Quasi-Geostrophic
framework. A cloud-revolving model (CRM) is forced with the large-scale
forcings (other than large-scale vertical motion) computed from the
quasi-geostrophic omega equation with input data from a reanalysis data set,
and the large-scale vertical motion is diagnosed interactively with the
simulated convection.
  Numerical results show that the positive feedback of convective heating to
large-scale dynamics is essential in amplifying the precipitation intensity to
the observed values. Orographic lifting is the most important dynamic forcing
in both events, while differential potential vorticity advection also
contributes to the triggering of the first event. Horizontal moisture advection
modulates the extreme events mainly by setting the environmental humidity,
which modulates the amplitude of the convection's response to the dynamic
forcings. When the CRM is replaced by either a single-column model (SCM) with
parameterized convection or a dry model with a reduced effective static
stability, the model results show substantial discrepancies compared with
reanalysis data. The reasons for these discrepancies are examined, and the
implications for global models and theoretical models are discussed.


title: Fractional Echoes

abstract:
  We report the observation of fractional echoes in a double-pulse excited
nonlinear system. Unlike standard echoes which appear periodically at delays
which are integer multiple of the delay between the two exciting pulses, the
fractional echoes appear at rational fractions of this delay. We discuss the
mechanism leading to this phenomenon, and provide the first experimental
demonstration of fractional echoes by measuring third harmonic generation in a
thermal gas of CO2 molecules excited by a pair of femtosecond laser pulses.


title:
Scaling of elliptic flow in heavy-ion collisions with the number of
  constituent quarks in a transport model

abstract:
  We studied the number of constituent quark scaling (NCQ) behaviour of
elliptic flow ($v_{2}$) under the framework of A Multi-Phase Transport model
(AMPT) at both top-RHIC and LHC energies. The NCQ-scaling in $v_{2}$ holds at
top-RHIC energy with AMPT string melting version, while it breaks in Pb+Pb
collisions at LHC energy using the same framework. The breaking of NCQ-scaling
at LHC energy has been studied by varying the magnitude of parton-parton
scattering cross-section and lifetime of hadronic cascade as implemented in
AMPT. We find that the breaking of NCQ scaling in Pb+Pb collisions at
$\sqrt{s_{NN}}$ =2.76 TeV is independent of the magnitude of parton-parton
cross-section and the later stage hadronic interactions. Further we observed
that scaling holds in a small collision system like Si+Si at $\sqrt{s_{NN}}$ =
2.76 TeV. We discussed that the breaking of NCQ scaling is possibly due to high
phase-space density of constituents quarks in Pb+Pb collisions at
$\sqrt{s_{NN}}$ = 2.76 TeV.


title: Inspiral into Gargantua

abstract:
  We model the inspiral of a compact object into a more massive black hole
rotating very near the theoretical maximum. We find that once the body enters
the near-horizon regime the gravitational radiation is characterized by a
constant frequency, equal to (twice) the horizon frequency, with an
exponentially damped profile. This contrasts with the usual "chirping" behavior
and, if detected, would constitute a "smoking gun" for a near-extremal black
hole in nature.


title: Twisted tensor products of $K^n$ with $K^m$

abstract:
  We find three families of twisting maps of K^m with K^n. One of them is
related to truncated quiver algebras, the second one consists of deformations
of the first and the third one requires m=n and yields algebras isomorphic to
M_n(K). Using these families and some exceptional cases we construct all
twisting maps of K^3 with K^3.


title: SPAMCART: a code for smoothed particle Monte Carlo radiative transfer

abstract:
  We present a code for generating synthetic SEDs and intensity maps from
Smoothed Particle Hydrodynamics simulation snapshots. The code is based on the
Lucy (1999) Monte Carlo Radiative Transfer method, i.e. it follows discrete
luminosity packets, emitted from external and/or embedded sources, as they
propagate through a density field, and then uses their trajectories to compute
the radiative equilibrium temperature of the ambient dust. The density is not
mapped onto a grid, and therefore the calculation is performed at exactly the
same resolution as the hydrodynamics. We present two example calculations using
this method. First, we demonstrate that the code strictly adheres to
Kirchhoff's law of radiation. Second, we present synthetic intensity maps and
spectra of an embedded protostellar multiple system. The algorithm uses data
structures that are already constructed for other purposes in modern particle
codes. It is therefore relatively simple to implement.


title:
Suppression of photon shot noise dephasing in a tunable coupling
  superconducting qubit

abstract:
  We demonstrate the suppression of photon shot noise dephasing in a
superconducting qubit by eliminating its dispersive coupling to the readout
cavity. This is achieved in a tunable coupling qubit, where the qubit frequency
and coupling rate can be controlled independently. We observe that the
coherence time approaches twice the relaxation time and becomes less sensitive
to thermal photon noise when the dispersive coupling rate is tuned from several
MHz to 22 kHz. This work provides a promising building block in circuit quantum
electrodynamics that can hold high coherence and be integrated into larger
systems.


title:
Three-waveform bidirectional pumping of single electrons with a silicon
  quantum dot

abstract:
  Semiconductor-based quantum dot single-electron pumps are currently the most
promising candidates for the direct realization of the emerging quantum
standard of the ampere in the International System of Units. Here, we discuss a
silicon quantum dot single-electron pump with radio frequency control over the
transparencies of entrance and exit barriers as well as the dot potential. We
show that our driving protocol leads to robust bidirectional pumping: one can
conveniently reverse the direction of the quantized current by changing only
the phase shift of one driving waveform with respect to the others. We also
study the improvement in the robustness of the current quantization owing to
the introduction of three control voltages in comparison with the two-waveform
driving. We anticipate that this pumping technique may be used in the future to
perform error counting experiments by pumping the electrons into and out of a
reservoir island monitored by a charge sensor.


title: HESS J1943+213: a non-classical high-frequency-peaked BL Lac object

abstract:
  HESS J1943+213 is an unidentified TeV source that is likely a
high-frequency-peaked BL Lac (HBL) object but also compatible with a pulsar
wind nebula (PWN) nature. Each of these enormously different astronomical
interpretations is supported by some of the observed unusual characteristics.
In order to finally classify and understand this object we took a three-pronged
approach, through time-domain, high angular resolution, and multi-frequency
radio studies. First, our deep time-domain observations with the Arecibo
telescope failed to uncover the putative pulsar powering the proposed PWN. We
conclude with ~70% certainty that HESS J1943+213 does not host a pulsar.
Second, long-baseline interferometry of the source with e-MERLIN at 1.5- and 5-
GHz, shows only a core, a point source at ~ 1 - 100 milli-arcsecond resolution.
Its 2013 flux density is about one-third lower than detected in 2011
observations with similar resolution. This radio variability of the core
strengthens the HBL object hypothesis. More evidence against the PWN scenario
comes, third, from the radio spectrum we compiled. The extended structure
follows a power-law behavior with spectral index alpha = -0.54 +- 0.04 while
the core component is flat spectrum (alpha = -0.03 +- 0.03). In contrast, the
radio synchrotron emission of PWNe predicts a single power-law distribution.
Overall we rule out the PWN hypothesis and conclude the source is a BL Lac
object. The consistently high fraction (70%) of the flux density from the
extended structure then leads us to conclude that HESS J1943+213 must be a
non-classical HBL object.


title:
Anisotropy in Cosmic-Ray Arrival Directions in the Southern Hemisphere
  with Six Years of Data from the IceCube Detector

abstract:
  The IceCube Neutrino Observatory has accumulated a total of 318 billion
cosmic-ray induced muon events between May 2009 and May 2015. This data set was
used for a detailed analysis of the cosmic-ray arrival direction anisotropy in
the TeV to PeV energy range. The observed global anisotropy features large
regions of relative excess and deficit, with amplitudes on the order of
$10^{-3}$ up to about 100 TeV. A decomposition of the arrival direction
distribution into spherical harmonics shows that most of the power is contained
in the low-multipole ($\ell\leq 4$) moments. However, higher multipole
components are found to be statistically significant down to an angular scale
of less than $10^{\circ}$, approaching the angular resolution of the detector.
Above 100 TeV, a change in the morphology of the arrival direction distribution
is observed, and the anisotropy is characterized by a wide relative deficit
whose amplitude increases with primary energy up to at least 5\,PeV, the
highest energies currently accessible to IceCube. No time dependence of the
large- and small-scale structures is observed in the six-year period covered by
this analysis. The high-statistics data set reveals more details on the
properties of the anisotropy and is potentially able to shed light on the
various physical processes that are responsible for the complex angular
structure and energy evolution.


title: GeoGebra Tools with Proof Capabilities

abstract:
  We report about significant enhancements of the complex algebraic geometry
theorem proving subsystem in GeoGebra for automated proofs in Euclidean
geometry, concerning the extension of numerous GeoGebra tools with proof
capabilities. As a result, a number of elementary theorems can be proven by
using GeoGebra's intuitive user interface on various computer architectures
including native Java and web based systems with JavaScript. We also provide a
test suite for benchmarking our results with 200 test cases.


title:
Investigation of the environment around close-in transiting exoplanets
  using CLOUDY

abstract:
  It has been suggested that hot stellar wind gas in a bow shock around an
exoplanet is sufficiently opaque to absorb stellar photons and give rise to an
observable transit depth at optical and UV wavelengths. In the first part of
this paper, we use the CLOUDY plasma simulation code to model the absorption
from X-ray to radio wavelengths by 1-D slabs of gas in coronal equilibrium with
varying densities ($10^{4}-10^{8} \, {\rm cm^{-3}}$) and temperatures
($2000-10^{6} \ {\rm K}$) illuminated by a solar spectrum. For slabs at coronal
temperatures ($10^{6} \ {\rm K}$) and densities even orders of magnitude larger
than expected for the compressed stellar wind ($10^{4}-10^{5} \, {\rm
cm^{-3}}$), we find optical depths orders of magnitude too small ($>
3\times10^{-7}$) to explain the $\sim3\%$ UV transit depths seen with Hubble.
Using this result and our modeling of slabs with lower temperatures ($2000-10^4
{\rm K}$), the conclusion is that the UV transits of WASP-12b and HD 189733b
are likely due to atoms originating in the planet, as the stellar wind is too
highly ionized. A corollary of this result is that transport of neutral atoms
from the denser planetary atmosphere outward must be a primary consideration
when constructing physical models. In the second part of this paper, additional
calculations using CLOUDY are carried out to model a slab of planetary gas in
radiative and thermal equilibrium with the stellar radiation field. Promising
sources of opacity from the X-ray to radio wavelengths are discussed, some of
which are not yet observed.


title: Tent Space Boundedness Via Extrapolation

abstract:
  We study the action of operators on tent spaces such as maximal operators,
Calder{\'o}n-Zygmund operators, Riesz potentials. We also consider singular
non-integral operators. We obtain boundedness as an application of
extrapolation methods in the Banach range. In the non Banach range, boundedness
results for Calder{\'o}n-Zygmund operators follows by using an appropriate
atomic theory. We end with some consequences on amalgalm spaces.


title:
Stock prices, inflation and inflation uncertainty in the U.S.: Testing
  the long-run relationship considering Dow Jones sector indexes

abstract:
  We test for the long-run relationship between stock prices, inflation and its
uncertainty for different U.S. sector stock indexes, over the period 2002M7 to
2015M10. For this purpose we use a cointegration analysis with one structural
break to capture the crisis effect, and we assess the inflation uncertainty
based on a time-varying unobserved component model. In line with recent
empirical studies we discover that in the long-run, the inflation and its
uncertainty negatively impact the stock prices, opposed to the well-known
Fisher effect. In addition we show that for several sector stock indexes the
negative effect of inflation and its uncertainty vanishes after the crisis
setup. However, in the short-run the results provide evidence in the favor of a
negative impact of uncertainty, while the inflation has no significant
influence on stock prices, except for the consumption indexes. The
consideration of business cycle effects confirms our findings, which proves
that the results are robust, both for the long-and the short-run relationships.


title:
Multi-domain Neural Network Language Generation for Spoken Dialogue
  Systems

abstract:
  Moving from limited-domain natural language generation (NLG) to open domain
is difficult because the number of semantic input combinations grows
exponentially with the number of domains. Therefore, it is important to
leverage existing resources and exploit similarities between domains to
facilitate domain adaptation. In this paper, we propose a procedure to train
multi-domain, Recurrent Neural Network-based (RNN) language generators via
multiple adaptation steps. In this procedure, a model is first trained on
counterfeited data synthesised from an out-of-domain dataset, and then fine
tuned on a small set of in-domain utterances with a discriminative objective
function. Corpus-based evaluation results show that the proposed procedure can
achieve competitive performance in terms of BLEU score and slot error rate
while significantly reducing the data needed to train generators in new, unseen
domains. In subjective testing, human judges confirm that the procedure greatly
improves generator performance when only a small amount of data is available in
the domain.


title: A remark on the multipliers on spaces of weak products of functions

abstract:
  If $\mathcal{H}$ denotes a Hilbert space of analytic functions on a region
$\Omega \subseteq \mathbb{C}^d$, then the weak product is defined by
$$\mathcal{H}\odot\mathcal{H}=\left\{h=\sum_{n=1}^\infty f_n g_n :
\sum_{n=1}^\infty \|f_n\|_{\mathcal{H}}\|g_n\|_{\mathcal{H}} <\infty\right\}.$$
We prove that if $\mathcal{H}$ is a first order holomorphic Besov Hilbert space
on the unit ball of $\mathbb{C}^d$, then the multiplier algebras of
$\mathcal{H}$ and of $\mathcal{H}\odot\mathcal{H}$ coincide.


title:
Fractional Fick's law for the boundary driven exclusion process with
  long jumps

abstract:
  A fractional Fick's law and fractional hydrostatics for the one dimensional
exclusion process with long jumps in contact with infinite reservoirs at
different densities on the left and on the right are derived.


title:
Accretion disk winds in active galactic nuclei: X-ray observations,
  models, and feedback

abstract:
  Powerful winds driven by active galactic nuclei (AGN) are often invoked to
play a fundamental role in the evolution of both supermassive black holes
(SMBHs) and their host galaxies, quenching star formation and explaining the
tight SMBH-galaxy relations. A strong support of this "quasar mode" feedback
came from the recent X-ray observation of a mildly relativistic accretion disk
wind in a ultraluminous infrared galaxy (ULIRG) and its connection with a
large-scale molecular outflow, providing a direct link between the SMBH and the
gas out of which stars form. Spectroscopic observations, especially in the
X-ray band, show that such accretion disk winds may be common in local AGN and
quasars. However, their origin and characteristics are still not fully
understood. Detailed theoretical models and simulations focused on radiation,
magnetohydrodynamic (MHD) or a combination of these two processes to
investigate the possible acceleration mechanisms and the dynamics of these
winds. Some of these models have been directly compared to X-ray spectra,
providing important insights into the wind physics. However, fundamental
improvements on these studies will come only from the unprecedented energy
resolution and sensitivity of the upcoming X-ray observatories, namely ASTRO-H
(launch date early 2016) and Athena (2028).


title: Generating asymptotics for factorially divergent sequences

abstract:
  The algebraic properties of formal power series, whose coefficients show
factorial growth and admit a certain well-behaved asymptotic expansion, are
discussed. It is shown that these series form a subring of $\mathbb{R}[[x]]$.
This subring is also closed under composition and inversion of power series. An
'asymptotic derivation' is defined which maps a power series to the asymptotic
expansion of its coefficients. Product and chain rules for this derivation are
deduced. With these rules asymptotic expansions of the coefficients of
implicitly defined power series can be obtained. The full asymptotic expansions
of the number of connected chord diagrams and the number of simple permutations
are given as examples.


title: A fully efficient time-parallelized quantum optimal control algorithm

abstract:
  We present a time-parallelization method that enables to accelerate the
computation of quantum optimal control algorithms. We show that this approach
is approximately fully efficient when based on a gradient method as
optimization solver: the computational time is approximately divided by the
number of available processors. The control of spin systems, molecular
orientation and Bose-Einstein condensates are used as illustrative examples to
highlight the wide range of application of this numerical scheme.


title: Moduli spaces of nonspecial pointed curves of arithmetic genus 1

abstract:
  In this paper we study the moduli stack ${\mathcal U}_{1,n}^{ns}$ of curves
of arithmetic genus 1 with n marked points, forming a nonspecial divisor. In
arXiv:1511.03797 this stack was realized as the quotient of an explicit scheme
$\widetilde{\mathcal U}_{1,n}^{ns}$, affine of finite type over ${\Bbb
P}^{n-1}$, by the action of ${\Bbb G}_m^n$ . Our main result is an explicit
description of the corresponding GIT semistable loci in $\widetilde{\mathcal
U}_{1,n}^{ns}$. This allows us to identify some of the GIT quotients with some
of the modular compactifications of ${\mathcal M}_{1,n}$ defined by Smyth in
arXiv:0902.3690 and arXiv:0808.0177.


title:
Neutron stars: from the inner crust to the core with the (Extended)
  Nambu-Jona-Lasinio model

abstract:
  Nucleonic matter is described within a su(2) extended Nambu-Jona-Lasinio
model. Several parametrizations with different nuclear matter saturation
properties are proposed. At subsaturation, nuclear pasta phases are calculated
within two methods: the coexistence-phases approximation and the compressible
liquid drop model, with the surface tension coefficient determined using a
geometrical approach at zero temperature. An unified equation of state of
stellar matter for the inner crust, with the nuclear pasta phases, and the core
is calculated. The mass and radius of neutron stars within this framework are
obtained for several families of hadronic and hybrid stars. The quark phase of
hybrid stars is described within the su(3) NJL model including a vector term.
Stellar macroscopic properties are in accordance with some of the recent
results in the literature.


title:
On minimizers of an isoperimetric problem with long-range interactions
  under a convexity constraint

abstract:
  We study a variational problem modeling the behavior at equilibrium of
charged liquid drops under convexity constraint. After proving well-posedness
of the model, we show C 1,1-regularity of minimizers for the Coulombic
interaction in dimension two. As a by-product we obtain that balls are the
unique minimizers for small charge. Eventually, we study the asymptotic
behavior of minimizers, as the charge goes to infinity.


title: Iterated Functions Systems, Blenders and Parablenders

abstract:
  We recast the notion of parablender introduced in [Berger2015] as a
parametric IFS. This is done using the concept of open covering property and
looking to parametric IFS as systems acting on jets.


title:
Fourth moment sum rule for the charge correlations of a two-component
  classical plasma

abstract:
  We consider an ionic fluid made with two species of mobile particles carrying
either a positive or a negative charge. We derive a sum rule for the fourth
moment of equilibrium charge correlations. Our method relies on the study of
the system response to the potential created by a weak external charge
distribution with slow spatial variations. The induced particle densities, and
the resulting induced charge density, are then computed within density
functional theory, where the free energy is expanded in powers of the density
gradients. The comparison with the predictions of linear response theory
provides a thermodynamical expression for the fourth moment of charge
correlations, which involves the isothermal compressibility as well as suitably
defined partial compressibilities. The familiar Stillinger-Lovett condition is
also recovered as a by-product of our method, suggesting that the fourth moment
sum rule should hold in any conducting phase. This is explicitly checked in the
low density regime, within the Abe-Meeron diagrammatical expansions. Beyond its
own interest, the fourth-moment sum rule should be useful for both analyzing
and understanding recently observed behaviours near the ionic critical point.


title: Reliable multiphoton generation in waveguide QED

abstract:
  In spite of decades of effort, it has not yet been possible to create
single-mode multiphoton states of light with high success probability and near
unity fidelity. Complex quantum states of propagating optical photons would be
an enabling resource for diverse protocols in quantum information science,
including for interconnecting quantum nodes in quantum networks. Here, we
propose several methods to generate heralded mutipartite entangled atomic and
photonic states by using the strong and long-range dissipative couplings
between atoms emerging in waveguide QED setups. Our theoretical analysis
demonstrates high success probabilities and fidelities are possible exploiting
waveguide QED properties.


title: Principles of Layered Attestation

abstract:
  Systems designed with measurement and attestation in mind are often layered,
with the lower layers measuring the layers above them. Attestations of such
systems, which we call layered attestations, must bundle together the results
of a diverse set of application-specific measurements of various parts of the
system. Some methods of layered attestation are more trustworthy than others,
so it is important for system designers to understand the trust consequences of
different system configurations. This paper presents a formal framework for
reasoning about layered attestations, and provides generic reusable principles
for achieving trustworthy results.


title: Serendipitous discovery of the faint solar twin Inti 1

abstract:
  Methods. We determine the atmospheric parameters and differential abundances
using high-resolution ($R \approx 50 000$), high signal-to-noise (S/N $\approx$
110 - 240 per pixel) Keck HIRES spectra for our solar twin candidate, the
previously known solar twin HD 45184, and the Sun.
  Results. For the bright solar twin HD 45184, we found $T_{\rm{eff}} = 5864
\pm 9$ K, log $g = 4.45 \pm 0.03$ dex, $v_{t} = 1.11 \pm 0.02$ $\rm{km\
{s}}^{-1}$, and [Fe/H]$ = 0.04 \pm 0.01$ dex, which are in good agreement with
previous works. The star Inti 1 has atmospheric parameters $T_{\rm{eff}} = 5837
\pm 11$ K, log $g = 4.42 \pm 0.03$ dex, $v_{t} = 1.04 \pm 0.02$ $\rm{km\
{s}}^{-1}$, and [Fe/H]$ = 0.07 \pm 0.01$ dex that are higher than solar. The
age and mass of the solar twin HD 45184 (3 Gyr and 1.05 $\rm{M_{\odot}}$) and
the faint solar twin Inti 1 (4 Gyr and 1.04 $\rm{M_{\odot}}$) were estimated
using isochrones. The differential analysis shows that HD 45184 presents an
abundance pattern that is similar to typical nearby solar twins; this means
this star has an enhanced refractory relative to volatile elements, while Inti
1 has an abundance pattern closer to solar, albeit somewhat enhanced in
refractories. The abundance pattern of HD 45184 and Inti 1 could be reproduced
by adding $\approx 3.5\ \rm{M_{\oplus}}$ and $\approx 1.5\ \rm{M_{\oplus}}$ of
Earth-like material to the convective zone of the Sun.
  Conclusions. The star Inti 1 is a faint solar twin, therefore, it could be
used to calibrate the zero points of different photometric systems. The distant
solar twin Inti 1 has an abundance pattern similar to the Sun with only a minor
enhancement in the refractory elements. It would be important to analyze other
distant solar twins to verify whether they share the Sun's abundance pattern or
if they are enhanced in refractories, as is the case in the majority of nearby
solar twins.


title: Generalized Metrics

abstract:
  The distance on a set is a comparative function. The smaller the distance
between two elements of that set, the closer, or more similar, those elements
are. Fr\'echet axiomatized the distance into what is today known as a metric.
In this thesis we study the generalization of Fr\'echet's axioms in various
ways including a partial metric, strong partial metric, partial
$n-\mathfrak{M}$etric and strong partial $n-\mathfrak{M}$etric. Those
generalizations allow for negative distances, non-zero distances between a
point and itself and even the comparison of $n-$tuples. We then present the
scoring of a DNA sequence, a comparative function that is not a metric but can
be modeled as a strong partial metric. Using the generalized metrics mentioned
above we create topological spaces and investigate convergence, limits and
continuity in them. As an application, we discuss contractiveness in the
language of our generalized metrics and present Banach-like fixed, common fixed
and coincidence point theorems.


title:
A Critical Analysis of One-Loop Neutrino Mass Models with Minimal Dark
  Matter

abstract:
  A recent paper investigated minimal R$\nu$MDM models with the type T1-iii and
T3 one-loop topologies. However, the candidate most-minimal model does not
possess an accidental symmetry - the scalar potential contains an explicit
symmetry breaking term, rendering the dark matter unstable. We present two
models that cure this problem. However, we further show that all of the
proposed minimal one-loop R$\nu$MDM models suffer from a second problem - an
additional source of explicit $Z_2$ symmetry breaking in the Yukawa sector. We
perform a more-general analysis to show that neutrino mass models using either
the type T3 or type T1-iii one-loop topologies do not give viable minimal dark
matter candidates. Consequently, one-loop models of neutrino mass with minimal
dark matter do not appear possible. Thus, presently there remains a single
known (three-loop) model of neutrino mass that gives stable dark matter without
invoking any new symmetries.


title: 3D Sisyphus Cooling of Trapped Ions

abstract:
  Using a laser polarization gradient, we realize 3D Sisyphus cooling of
$^{171}$Yb$^+$ ions confined in and near the Lamb-Dicke regime in a linear Paul
trap. The cooling rate and final mean motional energy of a single ion are
characterized as a function of laser intensity and compared to semiclassical
and quantum simulations. Sisyphus cooling is also applied to a linear string of
four ions to obtain a mean energy of 1-3 quanta for all vibrational modes, an
approximately order-of-magnitude reduction below Doppler cooled energies. This
is used to enable subsequent, efficient sideband laser cooling.


title:
HyperFace: A Deep Multi-task Learning Framework for Face Detection,
  Landmark Localization, Pose Estimation, and Gender Recognition

abstract:
  We present an algorithm for simultaneous face detection, landmarks
localization, pose estimation and gender recognition using deep convolutional
neural networks (CNN). The proposed method called, HyperFace, fuses the
intermediate layers of a deep CNN using a separate CNN followed by a multi-task
learning algorithm that operates on the fused features. It exploits the synergy
among the tasks which boosts up their individual performances. Additionally, we
propose two variants of HyperFace: (1) HyperFace-ResNet that builds on the
ResNet-101 model and achieves significant improvement in performance, and (2)
Fast-HyperFace that uses a high recall fast face detector for generating region
proposals to improve the speed of the algorithm. Extensive experiments show
that the proposed models are able to capture both global and local information
in faces and performs significantly better than many competitive algorithms for
each of these four tasks.


title: Decision Forests, Convolutional Networks and the Models in-Between

abstract:
  This paper investigates the connections between two state of the art
classifiers: decision forests (DFs, including decision jungles) and
convolutional neural networks (CNNs). Decision forests are computationally
efficient thanks to their conditional computation property (computation is
confined to only a small region of the tree, the nodes along a single branch).
CNNs achieve state of the art accuracy, thanks to their representation learning
capabilities. We present a systematic analysis of how to fuse conditional
computation with representation learning and achieve a continuum of hybrid
models with different ratios of accuracy vs. efficiency. We call this new
family of hybrid models conditional networks. Conditional networks can be
thought of as: i) decision trees augmented with data transformation operators,
or ii) CNNs, with block-diagonal sparse weight matrices, and explicit data
routing functions. Experimental validation is performed on the common task of
image classification on both the CIFAR and Imagenet datasets. Compared to state
of the art CNNs, our hybrid models yield the same accuracy with a fraction of
the compute cost and much smaller number of parameters.


title: An Intermediate Water Cherenkov Detector at J-PARC

abstract:
  Recent neutrino oscillation results have shown that the existing long
baseline experiments have some sensitivity to the effects of CP violation in
the neutrino sector. This sensitivity is currently statistically limited, but
the next generation of experiments, DUNE and Hyper-K, will provide an order of
magnitude more events. To reach the full potential of these datasets we must
achieve a commensurate improvement in our understanding of the systematic
uncertainties that beset them. This talk describes two proposed intermediate
detectors for the current and future long baseline oscillation experiments in
Japan, TITUS and NuPRISM. These detectors are discussed in the context of the
current T2K oscillation analysis, highlighting the ways in which they could
reduce the systematic uncertainty on this measurement. The talk also describes
the short baseline oscillation sensitivity of NuPRISM along with the neutrino
scattering measurements the detector makes possible.


title: The Blazhko Effect

abstract:
  We review the recent progress in our understanding of the Blazhko effect in
RR Lyrae stars.


title: Chiral Electroweak Currents in Nuclei

abstract:
  The development of the chiral dynamics based description of nuclear
electroweak currents is reviewed. Gerald E. (Gerry) Brown's role in basing
theoretical nuclear physics on chiral Lagrangians is emphasized. Illustrative
examples of the successful description of electroweak observables of light
nuclei obtained from chiral effective field theory are presented.


title: Thermodynamics, transport and relaxation in non-conformal theories

abstract:
  We study the equilibrium and near-equilibrium properties of a holographic
five-dimensional model consisting of Einstein gravity coupled to a scalar field
with a non-trivial potential. The dual four-dimensional gauge theory is not
conformal and, at zero temperature, exhibits a renormalisation group flow
between two different fixed points. We quantify the deviations from
conformality both in terms of thermodynamic observables and in terms of the
bulk viscosity of the theory. The ratio of bulk over shear viscosity violates
Buchel's bound. We study relaxation of small-amplitude, homogeneous
perturbations by computing the quasi-normal modes of the system at zero spatial
momentum. In this approximation we identify two different relaxation channels.
At high temperatures, the different pressures first become approximately equal
to one another, and subsequently this average pressure evolves towards the
equilibrium value dictated by the equation of state. At low temperatures, the
average pressure first evolves towards the equilibrium pressure, and only later
the different pressures become approximately equal to one another.


title:
Room-temperature magnetic topological semimetal state in half-metallic
  Heusler Co$_2$TiX (X=Si, Ge, or Sn)

abstract:
  Topological semimetals (TSMs) including Weyl semimetals and nodal-line
semimetals are expected to open the next frontier of condensed matter and
materials science. Although the first inversion breaking Weyl semimetal was
recently discovered in TaAs, its magnetic counterparts, i.e., the time-reversal
breaking Weyl and nodal line semimetals, remain elusive. They are predicted to
exhibit exotic properties distinct from the inversion breaking TSMs including
TaAs. In this paper, we identify the magnetic topological semimetal state in
the ferromagnetic half-metal compounds Co$_2$TiX (X=Si, Ge, or Sn) with Curie
temperatures higher than 350 K. Our first-principles band structure
calculations show that, in the absence of spin-orbit coupling, Co$_2$TiX
features three topological nodal lines. The inclusion of spin-orbit coupling
gives rise to Weyl nodes, whose momentum space locations can be controlled as a
function of the magnetization direction. Our results not only open the door for
the experimental realization of topological semimetal states in magnetic
materials at room temperatures, but also suggest potential applications such as
unusual anomalous Hall effects in engineered monolayers of the Co$_2$TiX
compounds at high temperatures.


title: Diphoton Excess through Dark Mediators

abstract:
  Preliminary ATLAS and CMS results from the first 13 TeV LHC run have
encountered an intriguing excess of events in the diphoton channel around the
invariant mass of 750 GeV. We investigate a possibility that the current excess
is due to a heavy resonance decaying to light metastable states, which in turn
give displaced decays to very highly collimated $e^+e^-$ pairs. Such decays may
pass the photon selection criteria, and successfully mimic the diphoton events,
especially at low counts. We investigate two classes of such models,
characterized by the following underlying production and decay chains: $gg \to
S\to A'A'\to (e^+e^-)(e^+e^-)$ and $q\bar q \to Z' \to sa\to (e^+e^-)(e^+e^-)$,
where at the first step a heavy scalar, $S$, or vector, $Z'$, resonances are
produced that decay to light metastable vectors, $A'$, or (pseudo-)scalars, $s$
and $a$. Setting the parameters of the models to explain the existing excess,
and taking the ATLAS detector geometry into account, we marginalize over the
properties of heavy resonances in order to derive the expected lifetimes and
couplings of metastable light resonances. We observe that in the case of $A'$,
the suggested range of masses and mixing angles $\epsilon$ is within reach of
several new-generation intensity frontier experiments.


title: New Convex Programs for Fisher's Market Model and its Generalizations

abstract:
  We present the following results pertaining to Fisher's market model:
  -We give two natural generalizations of Fisher's market model: In model M_1,
sellers can declare an upper bound on the money they wish to earn (and take
back their unsold good), and in model M_2, buyers can declare an upper bound on
the amount to utility they wish to derive (and take back the unused part of
their money).
  -We derive convex programs for the linear case of these two models by
generalizing a convex program due to Shmyrev and the Eisenberg-Gale program,
respectively.
  -We generalize the Arrow-Hurwicz theorem to the linear case of these two
models, hence deriving alternate convex programs.
  -For the special class of convex programs having convex objective functions
and linear constraints, we derive a simple set of rules for constructing the
dual program (as simple as obtaining the dual of an LP). Using these rules we
show a formal relationship between the two seemingly different convex programs
for linear Fisher markets, due to Eisenberg-Gale and Shmyrev; the duals of
these are the same, upto a change of variables.


title: Giant isotropic Nernst effect in an anisotropic Kondo semimetal

abstract:
  The "failed Kondo insulator" CeNiSn has long been suspected to be a nodal
metal, with a node in the hybridization matrix elements. Here we carry out a
series of Nernst effect experiments to delineate whether the severely
anisotropic magnetotransport coefficients do indeed derive from a nodal metal
or can simply be explained by a highly anisotropic Fermi surface. Our
experiments reveal that despite an almost 20-fold anisotropy in the Hall
conductivity, the large Nernst signal is isotropic. Taken in conjunction with
the magnetotransport anisotropy, these results provide strong support for an
isotropic Fermi surface with a large anisotropy in quasiparticle mass derived
from a nodal hybridization.


title: Systematics of Axion Inflation in Calabi-Yau Hypersurfaces

abstract:
  We initiate a comprehensive survey of axion inflation in compactifications of
type IIB string theory on Calabi-Yau hypersurfaces in toric varieties. For
every threefold with $h^{1,1} \le 4$ in the Kreuzer-Skarke database, we compute
the metric on K\"ahler moduli space, as well as the matrix of four-form axion
charges of Euclidean D3-branes on rigid divisors. These charges encode the
possibility of enlarging the field range via alignment. We then determine an
upper bound on the inflationary field range $\Delta \phi$ that results from the
leading instanton potential, in the absence of monodromy. The bound on the
field range in this ensemble is $\Delta \phi \lesssim 0.3 M_{\rm{pl}}$, in a
compactification where the smallest curve volume is $(2\pi)^2\alpha'$, and we
argue that the sigma model expansion is adequately controlled. The largest
increase resulting from alignment is a factor $\approx 2.6$. We also examine a
set of threefolds with $h^{1,1}$ up to $100$ and characterize their axion
charge matrices. We discuss how our findings could be modified by the effects
of orientifolding, seven-branes, and fluxes.


title: Ballistic miniband conduction in a graphene superlattice

abstract:
  Rational design of artificial lattices yields effects unavailable in simple
solids, and vertical superlattices of multilayer semiconductors are already
used in optical sensors and emitters. Manufacturing lateral superlattices
remains a much bigger challenge, with new opportunities offered by the use of
moire patterns in van der Waals heterostructures of graphene and hexagonal
crystals such as boron nitride (h-BN). Experiments to date have elucidated the
novel electronic structure of highly aligned graphene/h-BN heterostructures,
where miniband edges and saddle points in the electronic dispersion can be
reached by electrostatic gating. Here we investigate the dynamics of electrons
in moire minibands by transverse electron focusing, a measurement of ballistic
transport between adjacent local contacts in a magnetic field. At low
temperatures, we observe caustics of skipping orbits extending over hundreds of
superlattice periods, reversals of the cyclotron revolution for successive
minibands, and breakdown of cyclotron motion near van Hove singularities. At
high temperatures, we study the suppression of electron focusing by inelastic
scattering.


title:
Deterministic and stochastic aspects of the stability in an inverted
  pendulum under a generalized parametric excitation

abstract:
  In this paper, we explore the stability of an inverted pendulum under a
generalized parametric excitation described by a superposition of $N$ cosines
with different amplitudes and frequencies, based on a simple stability
condition that does not require any use of Lyapunov exponent, for example. Our
analysis is separated in 3 different cases: $N=1$, $N=2$, and $N$ very large.
Our results were obtained via numerical simulations by fourth-order Runge Kutta
integration of the non-linear equations. We also calculate the effective
potential also for $N>2$. We show then that numerical integrations recover a
wider region of stability that are not captured by the (approximated)
analytical method. We also analyze stochastic stabilization here: firstly, we
look the effects of external noise in the stability diagram by enlarging the
variance, and secondly, when $N$ is large, we rescale the amplitude by showing
that the diagrams for time survival of the inverted pendulum resembles the
exact case for $N=1$. Finally, we find numerically the optimal number of
cosines corresponding to the maximal survival probability of the pendulum.


title:
Testing the variation of fundamental constants by astrophysical methods:
  overview and prospects

abstract:
  By measuring the fundamental constants in astrophysical objects one can test
basic physical principles as space-time invariance of physical laws along with
probing the applicability limits of the standard model of particle physics. The
latest constraints on the fine structure constant alpha and the
electron-to-proton mass ratio mu obtained from observations at high redshifts
and in the Milky Way disk are reviewed. In optical range, the most accurate
measurements have already reached the sensitivity limit of available
instruments, and further improvements will be possible only with next
generation of telescopes and receivers. New methods of the wavelength
calibration should be realized to control systematic errors at the sub-pixel
level. In radio sector, the main tasks are the search for galactic and
extragalactic objects suitable for precise molecular spectroscopy as well as
high resolution laboratory measurements of molecular lines to provide accurate
frequency standards. The expected progress in the optical and radio
astrophysical observations is quantified.


title: Gamra: Simple Meshes for Complex Earthquakes

abstract:
  The static offsets caused by earthquakes are well described by elastostatic
models with a discontinuity in the displacement along the fault. A traditional
approach to model this discontinuity is to align the numerical mesh with the
fault and solve the equations using finite elements. However, this distorted
mesh can be difficult to generate and update. We present a new numerical
method, inspired by the Immersed Interface Method, for solving the elastostatic
equations with embedded discontinuities. This method has been carefully
designed so that it can be used on parallel machines on an adapted finite
difference grid. We have implemented this method in Gamra, a new code for earth
modelling. We demonstrate the correctness of the method with analytic tests,
and we demonstrate its practical performance by solving a realistic earthquake
model to extremely high precision.


title: Galactic survey of 44Ti sources with the IBIS telescope onboard INTEGRAL

abstract:
  We report the results of the deepest Galactic Plane (|b| < 17.5 deg) survey
in the 67.9 and 78.4 keV nuclear de-excitation lines of titanium-44 (44Ti)
performed using the data acquired with the IBIS/ISGRI instrument onboard the
INTEGRAL satellite during 12 years of operation. The peak sensitivity of our
survey reached an unprecedented level of $4.8\times10^{-6}$ erg s$^{-1}$
cm$^{-2}$ (3 sigma) that improves the sensitivity of the survey done by
CGRO/COMPTEL by a factor of ~5. As a result, constraining upper limits for all
sources from the catalog of Galactic supernova remnants (SNRs; Green 2014) are
derived. These upper limits can be used to estimate the exposure needed to
detect 44Ti emission from any known SNR using existing and prospective X- and
gamma-ray telescopes. Among the youngest Galactic SNRs, only Cas A shows
significant 44Ti emission flux in good agreement with the NuSTAR measurements.
We did not detect any other sources of titanium emission in the Galactic Plane
at significance level higher than 5 sigma confirming previous claims of the
rarity of such 44Ti-producing SNRs.


title:
Mid-infrared imaging- and spectro-polarimetric subarcsecond observations
  of NGC 1068

abstract:
  We present sub-arcsecond 7.5$-$13 $\mu$m imaging- and spectro-polarimetric
observations of NGC 1068 using CanariCam on the 10.4-m Gran Telescopio
CANARIAS. At all wavelengths, we find:
  (1) A 90 $\times$ 60 pc extended polarized feature in the northern ionization
cone, with a uniform $\sim$44$^{\circ}$ polarization angle. Its polarization
arises from dust and gas emission in the ionization cone, heated by the active
nucleus and jet, and further extinguished by aligned dust grains in the host
galaxy. The polarization spectrum of the jet-molecular cloud interaction at
$\sim$24 pc from the core is highly polarized, and does not show a silicate
feature, suggesting that the dust grains are different from those in the
interstellar medium.
  (2) A southern polarized feature at $\sim$9.6 pc from the core. Its
polarization arises from a dust emission component extinguished by a large
concentration of dust in the galaxy disc. We cannot distinguish between dust
emission from magnetically aligned dust grains directly heated by the jet close
to the core, and aligned dust grains in the dusty obscuring material
surrounding the central engine. Silicate-like grains reproduce the polarized
dust emission in this feature, suggesting different dust compositions in both
ionization cones.
  (3) An upper limit of polarization degree of 0.3 per cent in the core. Based
on our polarization model, the expected polarization of the obscuring dusty
material is $\lesssim$0.1 per cent in the 8$-$13 $\mu$m wavelength range. This
low polarization may be arising from the passage of radiation through aligned
dust grains in the shielded edges of the clumps.


title:
Young Stars and Planets Near the Sun in 2015: Five Takeaways and Five
  Predictions

abstract:
  I present a highly biased and skewed summary of IAU Symposium 314, "Young
Stars and Planets Near the Sun," held in Atlanta. This summary includes
takeaway thoughts about the rapidly evolving state of the field, as well as
crowd-sourced predictions for progress over the next ~10 years. We predict the
elimination of 1-2 of the currently recognized young moving groups, the
addition of 3 or more new moving groups within 100 pc, the continued lack of a
predictive theory of stellar mass, robust measurements of the gas and dust
content of circumstellar disks, and an ongoing struggle to achieve a consensus
definition for a planet.


title: On Mono-W Signatures in Spin-1 Simplified Models

abstract:
  The potential sensitivity to isospin-breaking effects makes LHC searches for
mono-W signatures promising probes of the coupling structure between the
Standard Model and dark matter. It has been shown, however, that the strong
sensitivity of the mono-W channel to the relative magnitude and sign of the
up-type and down-type quark couplings to dark matter is an artefact of
unitarity violation. We provide three different solutions to this mono-W
problem in the context of spin-1 simplified models and briefly discuss the
impact that our findings have on the prospects of mono-W searches at future LHC
runs.


title:
Strain Effects in Topological Insulators: Topological Order and the
  Emergence of Switchable Topological Interface States in
  Sb$_2$Te$_3$/Bi$_2$Te$_3$ Heterojunctions

abstract:
  Strain can induce a topological phase transition in bismuth dichalcogenides.
We present the phase diagram for 3D topological insulators Bi$_2$Te$_3$,
Sb$_2$Te$_3$, Bi$_2$Se$_3$ and Sb$_2$Se$_3$ with uniaxial and biaxal strain,
which show metallic and insulating phases, both topologically trivial and
non-trivial. In particular, uniaxial tension can drive Sb$_2$Te$_3$ into a
topologically trivial insulating phase. Thus, we propose a
Sb$_2$Te$_3$/Bi$_2$Te$_3$ heterojunction in which a topological interface state
arises in the common gap of this topological insulator-normal insulator
heterojunction that can be switched on or off by means of uniaxial strain. This
interface state is confined in the Sb$_2$Te$_3$ subsystem and is physically
protected from ambient impurities. Therefore, Sb$_2$Te$_3$/Bi$_2$Te$_3$
heterojunctions can host robust helical interface states with promising
spintronic applications.


title:
Towards the most general scalar-tensor theories of gravity: a unified
  approach in the language of differential forms

abstract:
  We use a description based on differential forms to systematically explore
the space of scalar-tensor theories of gravity. Within this formalism, we
propose a basis for the scalar sector at the lowest order in derivatives of the
field and in any number of dimensions. This minimal basis is used to construct
a finite and closed set of Lagrangians describing general scalar-tensor
theories invariant under Local Lorentz Transformations in a pseudo-Riemannian
manifold, which contains ten physically distinct elements in four spacetime
dimensions. Subsequently, we compute their corresponding equations of motion
and find which combinations are at most second order in derivatives in four as
well as arbitrary number of dimensions. By studying the possible exact forms
(total derivatives) and algebraic relations between the basis components, we
discover that there are only four Lagrangian combinations producing second
order equations, which can be associated with Horndeski's theory. In this
process, we identify a new second order Lagrangian, named kinetic Gauss-Bonnet,
that was not previously considered in the literature. However, we show that its
dynamics is already contained in Horndeski's theory. Finally, we provide a full
classification of the relations between different second order theories. This
allows us to clarify, for instance, the connection between different
covariantizations of Galileons theory. In conclusion, our formulation affords
great computational simplicity with a systematic structure. As a first step we
focus on theories with second order equations of motion. However, this new
formalism aims to facilitate advances towards unveiling the most general
scalar-tensor theories.


title:
General immunity and superadditivity of two-way Gaussian quantum
  cryptography

abstract:
  We consider two-way continuous-variable quantum key distribution, studying
its security against general eavesdropping strategies. Assuming the asymptotic
limit of many signals exchanged, we prove that two-way Gaussian protocols are
immune to coherent attacks. More precisely we show the general superadditivity
of the two-way security thresholds, which are proven to be higher than the
corresponding one-way counterparts in all cases. We perform the security
analysis first reducing the general eavesdropping to a two-mode coherent
Gaussian attack, and then showing that the superadditivity is achieved by
exploiting the random on/off switching of the two-way quantum communication.
This allows the parties to choose the appropriate communication instances to
prepare the key, accordingly to the tomography of the quantum channel. The
random opening and closing of the circuit represents, in fact, an additional
degree of freedom allowing the parties to convert, a posteriori, the two-mode
correlations of the eavesdropping into noise. The eavesdropper is assumed to
have no access to the on/off switching and, indeed, cannot adapt her attack. We
explicitly prove that this mechanism enhances the security performance, no
matter if the eavesdropper performs collective or coherent attacks.


title: A Strong Merger Shock in Abell 665

abstract:
  Deep (103 ks) \chandra\ observations of Abell 665 have revealed rich
structures in this merging galaxy cluster, including a strong shock and two
cold fronts. The newly discovered shock has a Mach number of $M$ = 3.0 $\pm$
0.6, propagating in front of a cold disrupted cloud. This makes Abell~665 the
second cluster where a strong merger shock of $M \approx$ 3 has been detected,
after the Bullet cluster. The shock velocity from jump conditions is consistent
with (2.7 $\pm$ 0.7) $\times$ 10$^3$ km sec$^{-1}$. The new data also reveal a
prominent southern cold front, with potentially heated gas ahead of it. Abell
665 also hosts a giant radio halo. There is a hint of diffuse radio emission
extending to the shock at the north, which needs to be examined with better
radio data. This new strong shock provides a great opportunity to study the
re-acceleration model with the X-ray and radio data combined.


title:
The Effect of Orbital Configuration on the Possible Climates and
  Habitability of Kepler-62f

abstract:
  As lower-mass stars often host multiple rocky planets, gravitational
interactions among planets can have significant effects on climate and
habitability over long timescales. Here we explore a specific case, Kepler-62f,
a potentially habitable planet in a five-planet system with a K2V host star.
N-body integrations reveal the stable range of initial eccentricities for
Kepler-62f is $0.00 \leqslant e \leqslant 0.32$, absent the effect of
additional, undetected planets. We simulate the tidal evolution of Kepler-62f
in this range and find that, for certain assumptions, the planet can be locked
in a synchronous rotation state. Simulations using LMD Generic GCM indicate
that with 3 bars of CO$_2$ in its atmosphere, Kepler-62f would only be warm
enough for surface liquid water at the upper limit of this eccentricity range,
providing it has a high planetary obliquity (between 60$^\circ$ and
90$^\circ$). A climate similar to modern-day Earth is possible for the entire
range of stable eccentricities if atmospheric CO$_2$ is increased to 5-bar
levels. In a low-CO$_2$ case, simulations with CCSM4 and LMD Generic GCM
indicate that increases in planetary obliquity and orbital eccentricity coupled
with an orbital configuration that places the summer solstice at or near
pericenter permit regions of the planet with above-freezing surface
temperatures. This may melt ice sheets formed during colder seasons. If
Kepler-62f is synchronously rotating and has an ocean, CO$_2$ levels above 3
bars would be required to distribute enough heat to the night side of the
planet to avoid atmospheric freeze-out and permit a large enough region of open
water at the planet's substellar point to remain stable. Overall, we find
multiple plausible combinations of orbital and atmospheric properties that
permit surface liquid water on Kepler-62f.


title:
Diagonalizing the Hamiltonian of $\lambda \phi^4$ Theory in 2 Space-Time
  Dimensions

abstract:
  We propose a new non-perturbative technique for calculating the field-theory
S-matrix directly from the eigenstates of the Hamiltonian. Our method involves
a discretized momentum space and a momentum cutoff, thereby truncating the
Hilbert space and making numerical diagonalization of the Hamiltonian
achievable. We show how to do this in the context of a simplified $\lambda
\phi^4$ theory in two space-time dimensions. We present the results of our
diagonalization, its dependence on time, its dependence on the parameters of
the theory and its renormalization.


title:
Scale invariant alternatives to general relativity. II. Dilaton
  properties

abstract:
  In the present paper, we revisit gravitational theories which are invariant
under TDiffs -- transverse (volume preserving) diffeomorphisms and global scale
transformations. It is known that these theories can be rewritten in an
equivalent diffeomorphism-invariant form with an action including an
integration constant (cosmological constant for the particular case of
non-scale-invariant unimodular gravity). The presence of this integration
constant, in general, breaks explicitly scale invariance and induces a runaway
potential for the (otherwise massless) dilaton, associated with the determinant
of the metric tensor. We show, however, that if the metric carries mass
dimension $\left[\text{GeV}\right]^{-2}$, the scale invariance of the system is
preserved, unlike the situation in theories in which the metric has mass
dimension different from $-2$. The dilaton remains massless and couples to
other fields only through derivatives, without any conflict with observations.
We observe that one can define a specific limit for fields and their
derivatives (in particular, the dilaton goes to zero, potentially related to
the small distance domain of the theory) in which the only singular terms in
the action correspond to the Higgs mass and the cosmological constant. We
speculate that the self-consistency of the theory may require the regularity of
the action, leading to the absence of the bare Higgs mass and cosmological
constant, whereas their small finite values may be generated by nonperturbative
effects.


title: CMB constraints on cosmic strings and superstrings

abstract:
  We present the first complete Markov chain Monte Carlo analysis of
cosmological models with evolving cosmic (super)string networks, using the
unconnected segment model in the unequal-time correlator formalism. For
ordinary cosmic string networks, we derive joint constraints on Lambda cold
dark matter (CDM) and string network parameters, namely the string tension Gmu,
the loop-chopping efficiency c_r and the string wiggliness \alpha. For cosmic
superstrings, we obtain joint constraints on the fundamental string tension
Gmu_F, the string coupling g_s, the self-interaction coefficient c_s, and the
volume of compact extra dimensions w. This constitutes the most comprehensive
CMB analysis of LambdaCDM cosmology + strings to date. For ordinary cosmic
string networks our updated constraint on the string tension is, in
relativistic units, Gmu<1.1x10^-7, while for cosmic superstrings our constraint
on the fundamental string tension is Gmu_F<2.8x10^-8, both obtained using
Planck2015 temperature and polarisation data.


title:
Selection bias in dynamically-measured super-massive black hole samples:
  its consequences and the quest for the most fundamental relation

abstract:
  We compare the set of local galaxies having dynamically measured black holes
with a large, unbiased sample of galaxies extracted from the Sloan Digital Sky
Survey. We confirm earlier work showing that the majority of black hole hosts
have significantly higher velocity dispersions sigma than local galaxies of
similar stellar mass. We use Monte-Carlo simulations to illustrate the effect
on black hole scaling relations if this bias arises from the requirement that
the black hole sphere of influence must be resolved to measure black hole
masses with spatially resolved kinematics. We find that this selection effect
artificially increases the normalization of the Mbh-sigma relation by a factor
of at least ~3; the bias for the Mbh-Mstar relation is even larger. Our Monte
Carlo simulations and analysis of the residuals from scaling relations both
indicate that sigma is more fundamental than Mstar or effective radius. In
particular, the Mbh-Mstar relation is mostly a consequence of the Mbh-sigma and
sigma-Mstar relations, and is heavily biased by up to a factor of 50 at small
masses. This helps resolve the discrepancy between dynamically-based black
hole-galaxy scaling relations versus those of active galaxies. Our simulations
also disfavour broad distributions of black hole masses at fixed sigma.
Correcting for this bias suggests that the calibration factor used to estimate
black hole masses in active galaxies should be reduced to values of fvir~1.
Black hole mass densities should also be proportionally smaller, perhaps
implying significantly higher radiative efficiencies/black hole spins. Reducing
black hole masses also reduces the gravitational wave signal expected from
black hole mergers.


title: Cosmological perturbations on the Phantom brane

abstract:
  We obtain a closed system of equations for scalar perturbations in a
multi-component braneworld. Our braneworld possesses a phantom-like equation of
state at late times, $w_{\rm eff} < -1$, but no big-rip future singularity. In
addition to matter and radiation, the braneworld possesses a new effective
degree of freedom - the 'Weyl fluid' or 'dark radiation'. Setting initial
conditions on super-Hubble spatial scales at the epoch of radiation domination,
we evolve perturbations of radiation, pressureless matter and the Weyl fluid
until the present epoch. We observe a gradual decrease in the amplitude of the
Weyl-fluid perturbations after Hubble-radius crossing, which results in a
negligible effect of the Weyl fluid on the evolution of matter perturbations on
spatial scales relevant for structure formation. Consequently, the quasi-static
approximation of Koyama and Maartens provides a good fit to the exact results
during the matter-dominated epoch. We find that the late-time growth of density
perturbations on the brane proceeds at a faster rate than in $\Lambda$CDM.
Additionally, the gravitational potentials $\Phi$ and $\Psi$ evolve differently
on the brane than in $\Lambda$CDM, for which $\Phi = \Psi$. On the brane, by
contrast, the ratio $\Phi/\Psi$ exceeds unity during the late matter-dominated
epoch ($z \lesssim 50$). These features emerge as "smoking gun" tests of
phantom brane cosmology and allow predictions of this scenario to be tested
against observations of galaxy clustering and large-scale structure.


title: On the Social Traits of Luminous Blue Variables

abstract:
  In a recent paper, Smith and Tombleson (2015) state that the Luminous Blue
Variables (LBVs) in the Milky Way and the Magellanic Clouds are isolated; that
they are not spatially associated with young O-type stars. They propose a novel
explanation that would overturn the standard view of LBVs. In this paper we
test their hypothesis for the LBVs in M31 and M33 as well as the LMC and SMC.
In M31 and M33, the LBVs are associated with luminous young stars and
supergiants appropriate to their luminosities and positions on the HR Diagram.
Moreover, in the Smith and Tombleson scenario most of the LBVs should be
runaway stars, but the stars' velocities are consistent with their positions in
the respective galaxies. In the Magellanic Clouds, those authors' sample was a
mixed population. We reassess their analysis, removing seven stars that have no
clear relation to LBVs. When we separate the more massive classical and the
less luminous LBVs, the classical LBVs have a distribution similar to the late
O-type stars, while the less luminous LBVs have a distribution like the red
supergiants. None of the confirmed LBVs have high velocities or are candidate
runaway stars. These results support the accepted description of LBVs as
evolved massive stars that have shed a lot of mass, and are now close to their
Eddington limit.


title:
Ideal Weyl semimetals in the chalcopyrites CuTlSe2, AgTlTe2, AuTlTe2 and
  ZnPbAs2

abstract:
  Weyl semimetals are new states of matter which feature novel Fermi arcs and
exotic transport phenomena. Based on first-principles calculations, we report
that the chalcopyrites CuTlSe2, AgTlTe2, AuTlTe2 and ZnPbAs2 are ideal Weyl
semimetals, having largely separated Weyl points (~ 0.05/A) and uncovered Fermi
arcs that are amenable to experimental detections. We also construct a minimal
effective model to capture the low-energy physics of this class of Weyl
semimetals. Our discovery is a major step toward a perfect playground of
intriguing Weyl semimetals and potential applications for low-power and
high-speed electronics.


title: Gravitational Instabilities in Circumstellar Disks

abstract:
  [Abridged] Star and planet formation are the complex outcomes of
gravitational collapse and angular momentum transport mediated by protostellar
and protoplanetary disks. In this review we focus on the role of gravitational
instability in this process. We begin with a brief overview of the
observational evidence for massive disks that might be subject to gravitational
instability, and then highlight the diverse ways in which the instability
manifests itself in protostellar and protoplanetary disks: the generation of
spiral arms, small scale turbulence-like density fluctuations, and
fragmentation of the disk itself. We present the analytic theory that describes
the linear growth phase of the instability, supplemented with a survey of
numerical simulations that aim to capture the non-linear evolution. We
emphasize the role of thermodynamics and large scale infall in controlling the
outcome of the instability. Despite apparent controversies in the literature,
we show a remarkable level of agreement between analytic predictions and
numerical results. We highlight open questions related to (1) the development
of a turbulent cascade in thin disks, and (2) the role of mode-mode coupling in
setting the maximum angular momentum transport rate in thick disks.


title:
Urca cooling pairs in the neutron star ocean and their effect on
  superbursts

abstract:
  An accretion outburst onto a neutron star deposits hydrogen-rich and/or
helium-rich material into the neutron star's envelope. Thermonuclear burning of
accreted material robustly produces Urca pairs\textrm{---}pairs of nuclei that
undergo cycles of $e^-$-capture and $\beta ^-$-decay. The strong $T^5$
dependence of the Urca cooling neutrino luminosity means that Urca pairs in the
neutron star interior potentially remove heat from accretion-driven nuclear
reactions. In this study, we identify Urca pairs in the neutron star's ocean
\textrm{---} a plasma of ions and electrons overlaying the neutron star crust
\textrm{---} and demonstrate that Urca cooling occurs at all depths in the
ocean. We find that Urca pairs in the ocean and crust lower the ocean's
steady-state temperature during an accretion outburst and that unstable carbon
ignition, which is thought to trigger superbursts, occurs deeper than it would
otherwise. Cooling superburst light curves, however, are only marginally
impacted by cooling from Urca pairs because the superburst peak radiative
luminosity $L_{\rm peak}$ is always much greater than the Urca pair neutrino
luminosity $L_{\nu}$ in the hot post-superburst ocean.


title: Hidden Photons in Aharonov-Bohm-Type Experiments

abstract:
  We discuss the Aharonov-Bohm effect in the presence of hidden photons
kinetically mixed with the ordinary electromagnetic photons. The hidden photon
field causes a slight phase shift in the observable interference pattern. It is
then shown how the limited sensitivity of this experiment can be largely
improved. The key observation is that the hidden photon field causes a leakage
of the ordinary magnetic field into the supposedly field-free region. The
direct measurement of this magnetic field can provide a sensitive experiment
with a good discovery potential, particularly below the $\sim$ meV mass range
for hidden photons.


title:
The abelian part of a compatible system and l-independence of the Tate
  conjecture

abstract:
  Let K be a number field and {V_l} be a rational strictly compatible system of
semisimple Galois representations of K arising from geometry. Let G_l and
V_l^ab be respectively the algebraic monodromy group and the maximal abelian
subrepresentation of V_l for all l. We prove that the system {V_l^ab} is also a
rational strictly compatible system under some group theoretic conditions,
e.g., when G_l' is connected and satisfies Hypothesis A for some prime l'. As
an application, we prove that the Tate conjecture for abelian variety X/K is
independent of l if the algebraic monodromy groups of the Galois
representations of X satisfy the required conditions.


title: Polaron Self-localization in White-light Emitting Hybrid Perovskites

abstract:
  Two-dimensional (2D) perovskites with general formula $APbX_4$ are attracting
increasing interest as solution processable, white-light emissive materials.
Recent studies have shown that their broadband emission is related to the
formation of intra-gap color centers; however, the nature and dynamics of the
emissive species have remained elusive. Here we show that the broadband
photoluminescence of the 2D perovskites $(EDBE)PbCl_4$ and $(EDBE)PbBr_4$ stems
from the localization of small polarons within the lattice distortion field.
Using a combination of spectroscopic techniques and first-principles
calculations, we infer the formation of ${Pb_2}^{3+}$, $Pb^{3+}$, and ${X_2}^-$
(where X=Cl or Br) species confined within the inorganic perovskite framework.
Due to strong Coulombic interactions, these species retain their original
excitonic character and form self-trapped polaron-excitons acting as radiative
color centers. These findings are expected to be applicable to a broad class of
white-light emitting perovskites with large polaron relaxation energy.


title: Quantum Phase Slip Noise

abstract:
  Quantum phase slips (QPS) generate voltage fluctuations in superconducting
nanowires. Employing Keldysh technique and making use of the phase-charge
duality arguments we develop a theory of QPS-induced voltage noise in such
nanowires. We demonstrate that quantum tunneling of the magnetic flux quanta
across the wire yields quantum shot noise which obeys Poisson statistics and is
characterized by a power law dependence of its spectrum $S_\Omega$ on the
external bias. In long wires $S_\Omega$ decreases with increasing frequency
$\Omega$ and vanishes beyond a threshold value of $\Omega$ at $T \to 0$.
Quantum coherent nature of QPS noise yields non-monotonous dependence of
$S_\Omega$ on $T$ at small $\Omega$.


title:
Measurability of the tidal deformability by gravitational waves from
  coalescing binary neutron stars

abstract:
  Combining new gravitational waveforms derived by long-term (14--16 orbits)
numerical-relativity simulations with waveforms by an effective-one-body (EOB)
formalism for coalescing binary neutron stars, we construct hybrid waveforms
and estimate the measurability for the dimensionless tidal deformability of the
neutron stars, $\Lambda$, by advanced gravitational-wave detectors. We focus on
the equal-mass case with the total mass $2.7M_\odot$. We find that for an event
at a hypothetical effective distance of $D_{\rm eff}=200$ Mpc, the
distinguishable difference in the dimensionless tidal deformability will be
$\approx 100$, 400, and 800 at 1-$\sigma$, 2-$\sigma$, and 3-$\sigma$ levels,
respectively, for advanced LIGO. If the true equation of state is stiff and the
typical neutron-star radius is $R \gtrsim 13 $ km, our analysis suggests that
the radius will be constrained within $\approx 1$ km at 2-$\sigma$ level for an
event at $D_{\rm eff}=200$ Mpc. On the other hand, if the true equation of
state is soft and the typical neutron-star radius is $R\lesssim 12$ km , it
will be difficult to narrow down the equation of state among many soft ones,
although it is still possible to discriminate the true one from stiff equations
of state with $R\gtrsim 13$ km. We also find that gravitational waves from
binary neutron stars will be distinguished from those from spinless binary
black holes at more than 2-$\sigma$ level for an event at $D_{\rm eff}=200$
Mpc. The validity of the EOB formalism, Taylor-T4, and Taylor-F2 approximants
as the inspiral waveform model is also examined.


title:
Primordial gravitational waves for universality classes of pseudoscalar
  inflation

abstract:
  Current bounds from the polarization of the CMB predict the scale-invariant
gravitational wave (GW) background of inflation to be out of reach for upcoming
GW interferometers. This prospect dramatically changes if the inflaton is a
pseudoscalar, in which case its generic coupling to any abelian gauge field
provides a new source of GWs, directly related to the dynamics of inflation.
This opens up new ways of probing the scalar potential responsible for cosmic
inflation. Dividing inflation models into universality classes, we analyze the
possible observational signatures. One of the most promising scenarios is
Starobinsky inflation, which may lead to observational signatures both in
direct GW detection as well as in upcoming CMB detectors. In this case, the
complementarity between the CMB and direct GW detection, as well as the
possibility of a multi-frequency analysis with upcoming ground and space based
GW interferometers, may provide a first clue to the microphysics of inflation.


title: Option spanning beyond $L_p$-models

abstract:
  \begin{abstract} The aim of this paper is to study the spanning power of
options in a static financial market that allows non-integrable assets. Our
findings extend and unify the results in [8,9,18] for $L_p$-models. We also
apply the spanning power properties to the pricing problem. In particular, we
show that prices on call and put options of a limited liability asset can be
uniquely extended by arbitrage to all marketed contingent claims written on the
asset.


title: Long-time stability of small FPU solitary waves

abstract:
  Small-amplitude waves in the Fermi-Pasta-Ulam (FPU) lattice with weakly
anharmonic interaction potentials are described by the generalized Korteweg-de
Vries (KdV) equation. Justification of the small-amplitude approximation is
usually performed on the time scale, for which dynamics of the KdV equation is
defined. We show how to extend justification analysis on longer time intervals
provided dynamics of the generalized KdV equation is globally well-posed in
Sobolev spaces and either the Sobolev norms are globally bounded or they grow
at most polynomially. The time intervals are extended respectively by the
logarithmic or double logarithmic factors in terms of the small amplitude
parameter. Controlling the approximation error on longer time intervals allows
us to deduce nonlinear metastability of small FPU solitary waves from orbital
stability of the KdV solitary waves.


title:
Reading off the non-geometric scalar potentials via topological data of
  the Calabi Yau manifolds

abstract:
  In the context of studying the 4D effective potentials of type IIB
non-geometric flux compactifications, this article has a twofold goal. First,
we present a modular invariant symplectic rearrangement of the tree level
non-geometric scalar potential arising from a flux superpotential which
includes the S-dual pairs of non-geometric fluxes $(Q, P)$, the standard NS-NS
and RR three-form fluxes $(F_3, H_3)$ and the geometric flux ($\omega$). This
`symplectic formulation' is valid for arbitrary numbers of K\"ahler moduli, and
the complex structure moduli which are implicitly encoded in a set of
symplectic matrices.
  In the second part, we further explicitly rewrite all the symplectic
ingredients in terms of saxionic and axionic components of the complex
structure moduli. The same leads to a compact form of the generic scalar
potential being explicitly written out in terms of all the real moduli/axions.
Moreover, the final form of the scalar potential needs only the knowledge of
some topological data (such as hodge numbers and the triple intersection
numbers) of the compactifying (CY) threefolds and their respective mirrors.
Finally, we demonstrate how the same is equivalent to say that, for a given
concrete example, various pieces of the scalar potential can be directly read
off from our generic proposal, without the need of starting from the K\"ahler-
and super-potentials.


title: The unbearable opaqueness of Arp 220

abstract:
  We explore the potential of imaging vibrationally excited molecular emission
at high angular resolution to better understand the morphology and physical
structure of the dense gas in Arp~220 and to gain insight into the nature of
the nuclear powering sources. Vibrationally excited emission of HCN is detected
in both nuclei with a very high ratio relative to the total $L_{FIR}$, higher
than in any other observed galaxy and well above what is observed in Galactic
hot cores. HCN $v_2=1f$ is observed to be marginally resolved in
$\sim60\times50$~pc regions inside the dusty $\sim100$~pc sized nuclear cores.
Its emission is centered on our derived individual nuclear velocities based on
HCO$^+$ emission ($V_{WN}=5342\pm4$ and $V_{EN}=5454\pm8$~\kms, for the western
and eastern nucleus, respectively). With virial masses within $r\sim25-30$~pc
based on the HCN~$v_2=1f$ line widths, we estimate gas surface densities (gas
fraction $f_g=0.1$) of $3\pm0.3\times10^4~M_\odot~\rm pc^{-2}$ (WN) and
$1.1\pm0.1\times10^4~M_\odot~\rm pc^{-2}$ (EN). The $4-3/3-2$ flux density
ratio could be consistent with optically thick emission, which would further
constrain the size of the emitting region to $>15$~pc (EN) and $>22$~pc (WN).
The absorption systems that may hide up to $70\%$ of the HCN and HCO$^+$
emission are found at velocities of $-50$~\kms~(EN) and $6$, $-140$, and
$-575$~\kms (WN) relative to velocities of the nuclei. Blueshifted absorptions
are the evidence of outflowing motions from both nuclei. The bright vibrational
emission implies the existence of a hot dust region radiatively pumping these
transitions. We find evidence of a strong temperature gradient that would be
responsible for both the HCN $v_2$ pumping and the absorbed profiles from the
vibrational ground state as a result of both continuum and self-absorption by
cooler foreground gas.


title: Modular Decomposition and Analysis of Registration based Trackers

abstract:
  This paper presents a new way to study registration based trackers by
decomposing them into three constituent sub modules: appearance model, state
space model and search method. It is often the case that when a new tracker is
introduced in literature, it only contributes to one or two of these sub
modules while using existing methods for the rest. Since these are often
selected arbitrarily by the authors, they may not be optimal for the new
method. In such cases, our breakdown can help to experimentally find the best
combination of methods for these sub modules while also providing a framework
within which the contributions of the new tracker can be clearly demarcated and
thus studied better. We show how existing trackers can be broken down using the
suggested methodology and compare the performance of the default configuration
chosen by the authors against other possible combinations to demonstrate the
new insights that can be gained by such an approach. We also present an open
source system that provides a convenient interface to plug in a new method for
any sub module and test it against all possible combinations of methods for the
other two sub modules while also serving as a fast and efficient solution for
practical tracking requirements.


title:
Scaling analysis and instantons for thermally-assisted tunneling and
  Quantum Monte Carlo simulations

abstract:
  We develop an instantonic calculus to derive an analytical expression for the
thermally-assisted tunneling decay rate of a metastable state in a fully
connected quantum spin model. The tunneling decay problem can be mapped onto
the Kramers escape problem of a classical random dynamical field. This
dynamical field is simulated efficiently by path integral Quantum Monte Carlo
(QMC). We show analytically that the exponential scaling with the number of
spins of the thermally-assisted quantum tunneling rate and the escape rate of
the QMC process are identical. We relate this effect to the existence of a
dominant instantonic tunneling path. The instanton trajectory is described by
nonlinear dynamical mean-field theory equations for a single site magnetization
vector, which we solve exactly. Finally, we derive scaling relations for the
"spiky" barrier shape when the spin tunnelling and QMC rates scale polynomially
with the number of spins $N$ while a purely classical over-the-barrier
activation rate scales exponentially with $N$.


title: Toward a Quantum Theory of Tachyon Fields

abstract:
  We construct momentum space expansions for the wave functions that solve the
Klein-Gordon and Dirac equations for tachyons, recognizing that the mass shell
for such fields is very different from what we are used to for ordinary (slower
than light) particles. We find that we can postulate commutation or
anticommutation rules for the operators that lead to physically sensible
results: causality, for tachyon fields, means that there is no connection
between spacetime points separated by a timelike interval. Calculating the
conserved charge and 4-momentum for these fields allows us to interpret the
number operators for particles and antiparticles in a consistent manner; and we
see that helicity plays a critical role for the spinor field. Some questions
about Lorentz invariance are addressed and some remain unresolved; and we show
how to handle the group representation for tachyon spinors.


title: Simultaneous Inference for High-dimensional Linear Models

abstract:
  This paper proposes a bootstrap-assisted procedure to conduct simultaneous
inference for high dimensional sparse linear models based on the recent
de-sparsifying Lasso estimator (van de Geer et al. 2014). Our procedure allows
the dimension of the parameter vector of interest to be exponentially larger
than sample size, and it automatically accounts for the dependence within the
de-sparsifying Lasso estimator. Moreover, our simultaneous testing method can
be naturally coupled with the margin screening (Fan and Lv 2008) to enhance its
power in sparse testing with a reduced computational cost, or with the
step-down method (Romano and Wolf 2005) to provide a strong control for the
family-wise error rate. In theory, we prove that our simultaneous testing
procedure asymptotically achieves the pre-specified significance level, and
enjoys certain optimality in terms of its power even when the model errors are
non-Gaussian. Our general theory is also useful in studying the support
recovery problem. To broaden the applicability, we further extend our main
results to generalized linear models with convex loss functions. The
effectiveness of our methods is demonstrated via simulation studies.


title:
On the class numbers of the fields of the $p^n$-torsion points of
  elliptic curves over $\mathbb{Q}$

abstract:
  Let $E$ be an elliptic curve over $\mathbb{Q}$ which has multiplicative
reduction at a fixed prime $p$. For each positive integer $n$ we put
$K_n:=\mathbb{Q}(E[p^n])$. The aim of this paper is to extend the author's
previous our results concerning with the order of the $p$-Sylow group of the
ideal class group of $K_n$ to more general setting. We also modify the previous
lower bound of the order and describe the new lower bound in terms of the
Mordell-Weil rank of $E(\mathbb{Q})$ and the ramification related to $E$.


title:
Radon induced hyperplasia: effective adaptation reducing the local doses
  in the bronchial epithelium

abstract:
  There is experimental and histological evidence that chronic irritation and
cell death may cause hyperplasia in the exposed tissue. As the heterogeneous
deposition of inhaled radon progeny results in high local doses at the peak of
the bronchial bifurcations, it was proposed earlier that hyperplasia occurs in
these deposition hot spots upon chronic radon exposure. The objective of the
present study is to quantify how the induction of basal cell hyperplasia
modulates the microdosimetric consequences of a given radon exposure. For this
purpose, numerical epithelium models were generated with spherical cell nuclei
of six different cell types based on histological data. Basal cell hyperplasia
was modelled by epithelium models with additional basal cells and increased
epithelium thickness. Microdosimetry for alpha-particles was performed by an
own-developed Monte-Carlo code. Results show that the average tissue dose, and
the average hit number and dose of basal cells decrease by the increase of the
measure of hyperplasia. Hit and dose distribution reveal that the induction of
hyperplasia may result in a basal cell pool which is shielded from alpha
radiation. It highlights that the exposure history affects the microdosimetric
consequences of a present exposure, while the biological and health effects may
also depend on previous exposures. The induction of hyperplasia can be
considered as a radioadaptive response at the tissue level. Such an adaptation
of the tissue challenges the validity of the application of the dose dose rate
effectiveness factor from a mechanistic point of view. As the location of
radiosensitive target cells may change due to previous exposures, dosimetry
models considering the tissue geometry characteristic of normal conditions may
be inappropriate for dose estimation in case of protracted exposures. As
internal exposures are frequently chronic, such changes in tissue...


title:
Two dimensional, electronic particle tracking in liquids with a
  graphene-based magnetic sensor array

abstract:
  The investigation of liquid flow at the nanoscale is a key area of applied
research with high relevance to Physics, Chemistry and Biology. We introduce a
method and a device that allows to spatially resolve liquid flow by integrating
an array of graphene-based magnetic sensors used for tracking the movement of
magnetic nanoparticles in the liquid under investigation. With a novel device
conception based on standard integration processes and experimentally verified
material parameters, we simulate the performance of a single sensor pixel, as
well as the whole array, for tracking magnetic nanoparticles. The results
demonstrate the ability (a) to detect individual nanoparticles in the liquid
and (b) to reconstruct particle trajectories across the sensor array as a
function of time, in what we call "Magnetic Nanoparticle Velocimetry"
technique. Being a non-optical detection method, potential applications include
particle tracking and flow analysis in opaque media at sub-micron scales.

categories: cond-mat.mes-hall physics.comp-ph physics.flu-dyn physics.ins-det


title: Non-equilibrium charge and spin transport in SFS point contacts

abstract:
  The conventional Josephson effect may be modified by introducing spin-active
scattering in the interface-layer of the junction. Here, we discuss a Josephson
junction consisting of two s-wave superconducting leads coupled over a
classical spin that precesses with the Larmor frequency due to an external
magnetic field. This magnetically active interface results in a time-dependent
boundary condition with different tunnelling amplitudes for spin-up and -down
quasiparticles and where the precession produces spin-flip scattering
processes. As a result, the Andreev states develop sidebands and a
non-equilibrium population that depend on the details of the spin precession.
The Andreev states carry a steady-state Josephson charge current and a
time-dependent spin current, whose current-phase relations could be used for
characterising the precessing spin. The spin current is supported by
spin-triplet correlations induced by the spin precession and creates a
feed-back effect on the classical spin in the form of a torque that shifts the
precession frequency.
  By applying a bias voltage, the Josephson frequency adds another complexity
to the situation and may create resonances together with the Larmor frequency.
These Shapiro resonances are manifested as torques and are, under suitable
conditions, able to reverse the direction of the classical spin in
sub-nanosecond time. Another characteristic feature is the subharmonic gap
structure in the dc charge current displaying an even-odd effect that is
attributable to precession-assisted multiple Andreev reflections.


title:
Explaining the apparent arbitrariness of the LDA-1/2 self-energy
  correction method applied to purely covalent systems

abstract:
  The LDA-1/2 method expands Slater's half occupation technique to infinite
solid state materials by introducing a self-energy potential centered at the
anions to cancel the energy associated with electron-hole self-interaction. To
avoid an infinite summation of long-ranged self-energy potentials they must be
trimmed at a variationally-defined cutoff radius. The method has been
successful in predicting accurate band gaps for a large number of elementary
and binary semiconductors. Nevertheless, there has been some confusion
regarding carbon and silicon, both in the cubic diamond structure, which
require different ionizations of the valence charge, 1/2 for carbon and 1/4 for
silicon respectively, to yield band gaps in agreement with experimental data.
We here analyze the spatial distribution of the valence electrons of these two
materials to conclude that in silicon and in carbon LDA-1/4 and LDA-1/2,
respectively, must be adopted for the proper cancellation of the self-energies.
Such analysis should be applied to other covalent semiconductors in order to
decide which ionization to adopt for the proper correction of the self-energy.