title:
Low frequency sound attenuation in a flow duct using a thin slow sound
  material

abstract:
  We present a thin subwavelength material that can be flush mounted to a duct
and which gives a large wide band attenuation at remarkably low frequencies in
air flow channels. To decrease the material thickness, the sound is slowed in
the material using folded side branch tubes. The impedance of the material is
compared to the optimal value, which differs greatly from the characteristic
impedance. In particular, the viscous and thermal effects have to be very small
to have high transmission losses. Grazing flow on this material increases the
losses at the interface between the flow and the material.


title:
Herschel/HIFI observations of the circumstellar ammonia lines in
  IRC+10216

abstract:
  New high-resolution far-infrared (FIR) observations of both ortho- and
para-NH3 transitions toward IRC+10216 were obtained with Herschel, with the
goal of determining the ammonia abundance and constraining the distribution of
NH3 in the envelope of IRC+10216. We used the Heterodyne Instrument for the Far
Infrared (HIFI) on board Herschel to observe all rotational transitions up to
the J=3 level (three ortho- and six para-NH3 lines). We conducted non-LTE
multilevel radiative transfer modelling, including the effects of near-infrared
(NIR) radiative pumping through vibrational transitions.
  We found that NIR pumping is of key importance for understanding the
excitation of rotational levels of NH3. The derived NH3 abundances relative to
molecular hydrogen were (2.8+-0.5)x10^{-8} for ortho-NH3 and
(3.2^{+0.7}_{-0.6})x10^{-8} for para-NH3, consistent with an ortho/para ratio
of 1. These values are in a rough agreement with abundances derived from the
inversion transitions, as well as with the total abundance of NH3 inferred from
the MIR absorption lines. To explain the observed rotational transitions,
ammonia must be formed near to the central star at a radius close to the end of
the wind acceleration region, but no larger than about 20 stellar radii (1
sigma confidence level).


title:
Mixer-Duplexer-Antenna Leaky-Wave System Based on Periodic Space-Time
  Modulation

abstract:
  We present a mixer-duplexer-antenna leaky-wave system based on periodic
space-time modulation. This system operates as a full transceiver, where the
upconversion and downconversion mixing operations are accomplished via
space-time transitions, the duplexing operation is induced by the nonreciprocal
nature of the structure, and the radiation operation is provided by the
leaky-wave nature of the wave. A rigorous electromagnetic solution is derived
for the dispersion relation and field distributions. The system is implemented
in the form of a spatio-temporally modulated microstrip leaky-wave structure
incorporating an array of sub-wavelengthly spaced varactors modulated by a
harmonic wave. In addition to the overall mixer-duplexer-antenna operation,
frequency beam scanning at fixed input frequency is demonstrated as one of the
interesting features of the system. A prototype is realized and demonstrated by
full-wave and experimental results.


title:
Nuclear response functions with finite range Gogny force: tensor terms
  and instabilities

abstract:
  A fully-antisymmetrized random phase approximation calculation employing the
continued fraction technique is performed to study nuclear matter response
functions with the finite range Gogny force. The most commonly used parameter
sets of this force, as well as some recent generalizations that include the
tensor terms are considered and the corresponding response functions are shown.
The calculations are performed at the first and second order in the continued
fraction expansion and the explicit expressions for the second order tensor
contributions are given. Comparison between first and second order continued
fraction expansion results are provided. The differences between the responses
obtained at the two orders turn to be more pronounced for the forces including
tensor terms than for the standard Gogny ones. In the vector channels the
responses calculated with Gogny forces including tensor terms are characterized
by a large heterogeneity, reflecting the different choices for the tensor part
of the interaction. For sake of comparison the response functions obtained
considering a G-matrix based nuclear interaction are also shown. As first
application of the present calculation, the possible existence of spurious
finite-size instabilities of the Gogny forces with or without tensor terms has
been investigated. The positive conclusion is that all the Gogny forces, but
the GT2 one, are free of spurious finite-size instabilities. In perspective,
the tool developed in the present paper can be inserted in the fitting
procedure to construct new Gogny-type forces.


title: Build It, Break It, Fix It: Contesting Secure Development

abstract:
  Typical security contests focus on breaking or mitigating the impact of buggy
systems. We present the Build-it Break-it Fix-it BIBIFI contest which aims to
assess the ability to securely build software not just break it. In BIBIFI
teams build specified software with the goal of maximizing correctness
performance and security. The latter is tested when teams attempt to break
other teams submissions. Winners are chosen from among the best builders and
the best breakers. BIBIFI was designed to be open-ended - teams can use any
language tool process etc. that they like. As such contest outcomes shed light
on factors that correlate with successfully building secure software and
breaking insecure software. During we ran three contests involving a total of
teams and two different programming problems. Quantitative analysis from these
contests found that the most efficient build-it submissions used CC but
submissions coded in a statically-typed language were less likely to have a
security flaw build-it teams with diverse programming-language knowledge also
produced more secure code. Shorter programs correlated with better scores.
Break-it teams that were also build-it teams were significantly better at
finding security bugs.


title:
On convergence of solutions to difference equations with additive
  perturbations

abstract:
  Various types of stabilizing controls lead to a deterministic difference
equation with the following property: once the initial value is positive, the
solution tends to the unique positive equilibrium. Introducing additive
perturbations can change this picture: we give examples of difference equations
experiencing additive perturbations which have solutions staying around zero
rather than tending to the unique positive equilibrium. When perturbations are
stochastic with a bounded support, we give an upper estimate for the
probability that the solution can stay around zero. Applying extra conditions
on the behavior of the map function $f$ at zero or on the amplitudes of
stochastic perturbations, we prove that the solution tends to the unique
positive equilibrium almost surely. In particular, this holds either for all
amplitudes when the right derivative of the map $f$ at zero exceeds one or,
independently of the behavior of $f$ at zero, when the amplitudes are not
square summable.


title: A de-gauging approach to physics beyond the Standard Model

abstract:
  By studying the t-J model for superconductivity, the Pati-Salam model and the
Haplon model for particle unifications, we extract their common feature which
is the spin-charge separation of fermions. This becomes a de-gauging process
for charged fermions by considering them as bound states of a neutral fermion
and charged or neutral bosons. We present a few examples including the
weak-charge-spin separation for the leptons in the Standard Model. Some
fundamental fermions can be obtained by continuing this de-gauging process for
different kinds of charges. Finally the binding forces of the bound states
might be provided by interactions related to spacetime symmetries such as
supersymmetry.


title:
Atomic scale nanoelectronics for quantum neuromorphic devices: comparing
  different materials

abstract:
  I review the advancements of atomic scale nanoelectronics towards quantum
neuromorphics. First, I summarize the key properties of elementary combinations
of few neurons, namely long-- and short--term plasticity, spike-timing
dependent plasticity (associative plasticity), quantumness and stochastic
effects, and their potential computational employment. Next, I review several
atomic scale device technologies developed to control electron transport at the
atomic level, including single atom implantation for atomic arrays and CMOS
quantum dots, single atom memories, Ag$_2$S and Cu$_2$S atomic switches,
hafnium based RRAMs, organic material based transistors, Ge$_2$Sb$_2$Te$_5$
synapses. Each material/method proved successful in achieving some of the
properties observed in real neurons. I compare the different methods towards
the creation of a new generation of naturally inspired and biophysically
meaningful artificial neurons, in order to replace the rigid CMOS based
neuromorphic hardware. The most challenging aspect to address appears to obtain
both the stochastic/quantum behavior and the associative plasticity, which are
currently observed only below and above 20 nm length scale respectively, by
employing the same material.


title: Learning to Optimize

abstract:
  Algorithm design is a laborious process and often requires many iterations of
ideation and validation. In this paper, we explore automating algorithm design
and present a method to learn an optimization algorithm, which we believe to be
the first method that can automatically discover a better algorithm. We
approach this problem from a reinforcement learning perspective and represent
any particular optimization algorithm as a policy. We learn an optimization
algorithm using guided policy search and demonstrate that the resulting
algorithm outperforms existing hand-engineered algorithms in terms of
convergence speed and/or the final objective value.


title: One-loop one-point functions in gauge-gravity dualities with defects

abstract:
  We initiate the calculation of loop corrections to correlation functions in
4D defect CFTs. More precisely, we consider N=4 SYM with a codimension-one
defect separating two regions of space, x_3>0 and x_3<0, where the gauge group
is SU(N) and SU(N-k), respectively. This set-up is made possible by some of the
real scalar fields acquiring a non-vanishing and x_3-dependent vacuum
expectation value for x_3>0. The holographic dual is the D3-D5 probe brane
system where the D5 brane geometry is AdS_4 x S^2 and a background gauge field
has k units of flux through the S^2. We diagonalise the mass matrix of the
defect CFT making use of fuzzy-sphere coordinates and we handle the
x_3-dependence of the mass terms in the 4D Minkowski space propagators by
reformulating these as standard massive AdS_4 propagators. Furthermore, we show
that only two Feynman diagrams contribute to the one-loop correction to the
one-point function of any single-trace operator and we explicitly calculate
this correction in the planar limit for the simplest chiral primary. The result
of this calculation is compared to an earlier string-theory computation in a
certain double-scaling limit, finding perfect agreement. Finally, we discuss
how to generalise our calculation to any single-trace operator, to finite N and
to other types of observables such as Wilson loops.


title: Ensemble Average Theory of Gravity

abstract:
  We put forward the idea that all the theoretically consistent models of
gravity have contributions to the observed gravity interaction. In this
formulation, each model comes with its own Euclidean path-integral weight where
general relativity (GR) has automatically the maximum weight in high-curvature
regions. We employ this idea in the framework of Lovelock models and show that
in four dimensions the result is a specific form of the $f(R,G)$ model. This
specific $f(R,G)$ satisfies the stability conditions and possesses
self-accelerating solutions. Our model is consistent with the local tests of
gravity since its behavior is the same as in GR for the high-curvature regime.
In the low-curvature regime the gravitational force is weaker than in GR, which
can be interpreted as the existence of a repulsive fifth force for very large
scales. Interestingly, there is an intermediate-curvature regime where the
gravitational force is stronger in our model compared to GR. The different
behavior of our model in comparison with GR in both low- and
intermediate-curvature regimes makes it observationally distinguishable from
$\Lambda$CDM.


title: Irreducible p-constant characters of finite reflection groups

abstract:
  A complex irreducible character of a finite group G is said to be p-constant,
for some prime p dividing the order of G, if it takes constant value at the set
of p-singular elements of G. In this paper we classify irreducible p-constant
characters for finite reflection groups, nilpotent groups and complete monomial
groups. We also propose some conjectures about the structure of the groups
admitting such characters.


title:
Multitimescale method for approximating the path action relevant to
  non-equilibrium statistical physics

abstract:
  A path integral formalism has been proposed recently for non-equilibrium
statistical physics applications by the author. In this contribution we outline
an efficient method for its numerical evaluation. The method used is based on
the multiscale MCMC method of Ceperley and co-workers in quantum applications.
A significant new feature of the method proposed is that the time endpoint is
not fixed and indeed the endpoint sample is the principle object of interest.


title:
A characteristic of local existence for fractional heat equations in
  Lebesgue spaces

abstract:
  In this paper, we consider the fractional heat equation
$u_{t}=\triangle^{\alpha/2}u+f(u)$ with Dirichlet boundary conditions on the
ball $B_{R}\subset \mathbb{R}^{d}$, where $\triangle^{\alpha/2}$ is the
fractional Laplacian, $f:[0,\infty)\rightarrow [0,\infty)$ is continuous and
non-decreasing. We present the characterisations of $f$ to ensure the equation
has a local solution in $L^{q}(B_{R})$ provided that the non-negative initial
data $u_{0}\in L^{q}(B_{R})$. For $q>1$ and $1<\alpha\leq 2$, we show that the
equation has a local solution in $L^{q}(B_{R})$ if and only if
$\lim_{s\rightarrow \infty}\sup s^{-(1+\alpha q/d)}f(s)=\infty$; and for $q=1$
and $1<\alpha\leq 2$ if and only if
$\int_{1}^{\infty}s^{-(1+\alpha/d)}F(s)ds<\infty$, where $F(s)=\sup_{1\leq
t\leq s}f(t)/t$. When $\lim_{s\rightarrow 0}f(s)/s<\infty$, the same
characterisations holds for the fractional heat equation on the whole space
$\mathbb{R}^{d}$.


title: Module structure on $U(\mathfrak{h})$ for Kac-Moody algebras

abstract:
  Let $\g$ be an arbitrary Kac-Moody algebra with a Cartan sualgebra $\h$. In
this paper, we determine the category of $\g$-modules that are free
$U(\h)$-modules of rank 1.


title:
Conductivity of pure graphene: Theoretical approach using the
  polarization tensor

abstract:
  We obtain analytic expressions for the conductivity of pristine (pure)
graphene in the framework of the Dirac model using the polarization tensor in
(2+1)-dimensions defined along the real frequency axis. It is found that at
both zero and nonzero temperature $T$ the in-plane and out-of-plane
conductivities of graphene are equal to each other with a high precision and
essentially do not depend on the wave vector. At $T=0$ the conductivity of
graphene is real and equal to $\sigma_0=e^2/(4\hbar)$ up to small nonlocal
corrections in accordance with many authors. At some fixed $T\neq 0$ the real
part of the conductivity varies between zero at low frequencies $\omega$ and
$\sigma_0$ for optical $\omega$. If $\omega$ is fixed, the conductivity varies
between $\sigma_0$ at low $T$ and zero at high $T$. The imaginary part of the
conductivity of graphene is shown to depend on the ratio of $\omega$ to $T$. In
accordance to the obtained asymptotic expressions, at fixed $T$ it varies from
infinity at $\omega=0$ to a negative minimum value reached at some $\omega$,
and then approaches to zero with further increase of $\omega$. At fixed
$\omega$ the imaginary part of the conductivity varies from zero at $T=0$,
reaches a negative minimum at some $T$ and then goes to infinity together with
$T$. The numerical computations of both the real and imaginary parts of the
conductivity are performed. The above results are obtained in the framework of
quantum electrodynamics at nonzero temperature and can be generalized for
graphene samples with nonzero mass gap parameter and chemical potential.


title: Particle-Vortex Duality from 3d Bosonization

abstract:
  We provide a simple derivation of particle-vortex duality in d=2+1
dimensions. Our starting point is a relativistic form of flux attachment,
designed to transmute the statistics of particles. From this seed, we derive a
web of new dualities. These include particle-vortex duality for bosons as well
as the recently discovered counterpart for fermions.


title: Hofstadter's Butterfly in Quantum Geometry

abstract:
  We point out that the recent conjectural solution to the spectral problem for
the Hamiltonian $H=e^{x}+e^{-x}+e^{p}+e^{-p}$ in terms of the refined
topological invariants of a local Calabi-Yau geometry has an intimate relation
with two-dimensional non-interacting electrons moving in a periodic potential
under a uniform magnetic field. In particular, we find that the quantum
A-period, determining the relation between the energy eigenvalue and the Kahler
modulus of the Calabi-Yau, can be found explicitly when the quantum parameter
$q=e^{i\hbar}$ is a root of unity, that its branch cuts are given by
Hofstadter's butterfly, and that its imaginary part counts the number of states
of the Hofstadter Hamiltonian. The modular double operation, exchanging $\hbar$
and $4\pi^2/\hbar$, plays an important role.

categories: hep-th cond-mat.mes-hall cond-mat.stat-mech math-ph math.MP


title:
Calibration of quasi-static aberrations in exoplanet direct-imaging
  instruments with a Zernike phase-mask sensor. II. Concept validation with
  ZELDA on VLT/SPHERE

abstract:
  Warm or massive gas giant planets, brown dwarfs, and debris disks around
nearby stars are now routinely observed by dedicated high-contrast imaging
instruments on large, ground-based observatories. These facilities include
extreme adaptive optics (ExAO) and state-of-the-art coronagraphy to achieve
unprecedented sensitivities for exoplanet detection and spectral
characterization. However, differential aberrations between the ExAO sensing
path and the science path represent a critical limitation for the detection of
giant planets with a contrast lower than a few $10^{-6}$ at very small
separations (<0.3\as) from their host star. In our previous work, we proposed a
wavefront sensor based on Zernike phase contrast methods to circumvent this
issue and measure these quasi-static aberrations at a nanometric level. We
present the design, manufacturing and testing of ZELDA, a prototype that was
installed on VLT/SPHERE during its reintegration in Chile. Using the internal
light source of the instrument, we performed measurements in the presence of
Zernike or Fourier modes introduced with the deformable mirror. Our
experimental and simulation results are consistent, confirming the ability of
our sensor to measure small aberrations (<50 nm rms) with nanometric accuracy.
We then corrected the long-lived non-common path aberrations in SPHERE based on
ZELDA measurements. We estimated a contrast gain of 10 in the coronagraphic
image at 0.2\as, reaching the raw contrast limit set by the coronagraph in the
instrument. The simplicity of the design and its phase reconstruction algorithm
makes ZELDA an excellent candidate for the on-line measurements of quasi-static
aberrations during the observations. The implementation of a ZELDA-based
sensing path on the current and future facilities (ELTs, future space missions)
could ease the observation of the cold gaseous or massive rocky planets around
nearby stars.


title: A WISE Census of Young Stellar Objects in Canis Major

abstract:
  With the Wide-Field Infrared Survey Explorer (WISE), we searched for young
stellar objects (YSOs) in a 100 deg^2 region centered on the lightly studied
Canis Major star forming region. Applying stringent magnitude cuts to exclude
the majority of extragalactic contaminants, we find 144 Class I candidates and
335 Class II candidates. The sensitivity to Class II candidates is limited by
their faintness at the distance to Canis Major (assumed as 1000 pc). More than
half the candidates (53%) are found in 16 groups of more than four members,
including four groups with more than 25 members each. The ratio of Class II to
Class I objects, N_II/N_I, varies from 0.4 to 8.3 in just the largest four
groups. We compare our results to those obtainable with combined Two Micron All
Sky Survey (2MASS) and post-cryogenic Spitzer Space Telescope data; the latter
approach recovers missing Class II sources. Via a comparison to protostars
characterized with the Herschel Space Observatory, we propose new WISE color
criteria for flat-spectrum and Class 0 protostars, finding 80 and seven of
these, respectively. The distribution of YSOs in CMa OB1 is consistent with
supernova-induced star formation, although the diverse N_II/N_I ratios are
unexpected if this parameter traces age and the YSOs are due to the same
supernova. Less massive clouds feature larger N_II/N_I ratios, suggesting that
initial conditions play a role in determining this quantity.


title: Feedback-tuned noise-resilient gates for encoded spin qubits

abstract:
  Two level quantum mechanical systems like spin 1/2 particles lend themselves
as a natural qubit implementation. However, encoding a single qubit in several
spins reduces the resources necessary for qubit control and can protect from
decoherence channels. While several varieties of such encoded spin qubits have
been implemented, accurate control remains challenging, and leakage out of the
subspace of valid qubit states is a potential issue. Here, we realize
high-fidelity single qubit operations for a qubit encoded in two electron spins
in GaAs quantum dots by iterative tuning of the all-electrical control pulses.
Using randomized benchmarking, we find an average gate fidelity of $\mathcal{F}
= (98.5 \pm 0.1)\,\%$ and determine the leakage rate between the computational
subspace and other states to $\mathcal{L} = (0.4\pm0.1)\,\%$. These results
also demonstrate that high fidelity gates can be realized even in the presence
of nuclear spins as in III-V semiconductors.


title: Adiabatic Quantum Search in Open Systems

abstract:
  Adiabatic quantum algorithms represent a promising approach to universal
quantum computation. Whilst in a closed system these algorithms are limited by
avoided level crossings, where the gap becomes exponentially small in the
system size, their robustness in open systems remains unresolved. We study the
dynamics in the proximity of such an avoided level crossing associated with the
adiabatic quantum search algorithm in a quantum system that is coupled to a
generic environment. At zero temperature, we find that the algorithm remains
scalable provided the noise spectral density of the environment decays
sufficiently fast at low frequencies. At finite temperature, however,
scattering processes render the algorithm inefficient and no quantum speedup
can be achieved. Owing to the generic nature of our model, we expect our
results to be widely applicable to other adiabatic quantum algorithms.


title:
Evolution of long-lived globular cluster stars III. Effect of the
  initial helium spread on the position of stars in a synthetic
  Hertzsprung-Russell diagram

abstract:
  Context. Globular clusters host multiple populations of long-lived low-mass
stars whose origin remains an open question. Several scenarios have been
proposed to explain the associated photometric and spectroscopic peculiarities.
They differ, for instance, in the maximum helium enrichment they predict for
stars of the second population, which these stars can inherit at birth as the
result of the internal pollution of the cluster by different types of stars of
the first population. Aims. We present the distribution of helium-rich stars in
present-day globular clusters as it is expected in the original framework of
the fast-rotating massive stars scenario (FRMS) as first-population polluters.
We focus on NGC 6752. (to be continued)


title: Massive Black Hole Binary Mergers in Dynamical Galactic Environments

abstract:
  Gravitational Waves (GW) have now been detected from stellar-mass black hole
binaries, and the first observations of GW from Massive Black Hole (MBH)
Binaries are expected within the next decade. Pulsar Timing Arrays (PTA), which
can measure the years long periods of GW from MBHB, have excluded many standard
predictions for the amplitude of a stochastic GW Background (GWB). We use
coevolved populations of MBH and galaxies from hydrodynamic, cosmological
simulations ('Illustris') to calculate a predicted GWB. The most advanced
predictions so far have included binary hardening mechanisms from individual
environmental processes. We present the first calculation including all of the
environmental mechanisms expected to be involved: dynamical friction, stellar
'loss-cone' scattering, and viscous drag from a circumbinary disk. We find that
MBH binary lifetimes are generally multiple gigayears, and only a fraction
coalesce by redshift zero. For a variety of parameters, we find all GWB
amplitudes to be below the most stringent PTA upper limit of
$A_{\textrm{yr}^{-1}} \approx 10^{-15}$. Our fairly conservative fiducial model
predicts an amplitude of $A_{\textrm{yr}^{-1}} \approx 0.4\times
10^{-15}$---less than a factor of three below the current limit. At lower
frequencies, we find $A_{0.1\,\textrm{yr}^{-1}} \approx 1.5\times 10^{-15}$
with spectral indices between $-0.4$ and $-0.6$---significantly flatter than
the canonical value of $-2/3$ due to purely GW-driven evolution. Typical MBHB
driving the GWB signal come from redshifts around $0.3$, with total masses of a
few times $10^9\,M_\odot$, and in host galaxies with very large stellar masses.
Even without GWB detections, our results can be connected to observations of
dual AGN to constrain binary evolution.


title: 2D quantum gravity on compact Riemann surfaces with non-conformal matter

abstract:
  We study the gravitational action induced by coupling two-dimensional
non-conformal, massive matter to gravity on a compact Riemann surface. We
express this gravitational action in terms of finite and well-defined
quantities for any value of the mass. A small-mass expansion gives back the
Liouville action in the massless limit, the Mabuchi and Aubin-Yau actions to
first order, as well as an infinite series of higher-order contributions
written in terms of purely geometric quantities.


title: Emergent Dimensions and Braneworlds from Large-N Confinement

abstract:
  $\mathcal{N}=1$ $SU(N)$ super-Yang-Mills theory on $\mathbb{R}^3\times S^1$
is believed to have a smooth dependence on the circle size $L$. Making $L$
small leads to calculable non-perturbative color confinement, mass gap, and
string tensions. For finite $N$, the small-$L$ low-energy dynamics is described
by a three-dimensional effective theory. The large-$N$ limit, however, reveals
surprises: the infrared dual description is in terms of a theory with an
emergent fourth dimension, curiously reminiscent of T-duality in string theory.
Here, however, the emergent dimension is a lattice, with momenta related to the
$S^1$-winding of the gauge field holonomy, which takes values in
$\mathbb{Z}_N$. Furthermore, the low-energy description is given by a
non-trivial gapless theory, with a space-like $z=2$ Lifshitz scale invariance
and operators that pick up anomalous dimensions as $L$ is increased.
Supersymmetry-breaking deformations leave the long-distance theory
scale-invariant, but change the Lifshitz scaling exponent to $z=1$, and lead to
an emergent Lorentz symmetry at small $L$. Adding a small number of fundamental
fermion fields leads to matter localized on three-dimensional branes in the
emergent four-dimensional theory.


title:
Mocking the Weak Lensing universe: the LensTools python computing
  package

abstract:
  We present a newly developed software package which implements a wide range
of routines frequently used in Weak Gravitational Lensing (WL). With the
continuously increasing size of the WL scientific community we feel that easy
to use Application Program Interfaces (APIs) for common calculations are a
necessity to ensure efficiency and coordination across different working
groups. Coupled with existing open source codes, such as CAMB and Gadget2,
LensTools brings together a cosmic shear simulation pipeline which,
complemented with a variety of WL feature measurement tools and parameter
sampling routines, provides easy access to the numerics for theoretical studies
of WL as well as for experiment forecasts. Being implemented in python,
LensTools takes full advantage of a range of state--of--the art techniques
developed by the large and growing open--source software community
(scipy,pandas,astropy,scikit-learn,emcee). We made the LensTools code available
on the Python Package Index and published its documentation on
http://lenstools.readthedocs.io


title:
A unified framework for magic state distillation and multi-qubit
  gate-synthesis with reduced resource cost

abstract:
  The standard approach to fault-tolerant quantum computation is to store
information in a quantum error correction code, such as the surface code, and
process information using a strategy that can be summarized as
distill-then-synthesize. In the distill step, one performs several rounds of
distillation to create high-fidelity logical qubits in a magic state. Each such
magic state provides one good T gate. In the synthesize step, one seeks the
optimal decomposition of an algorithm into a sequence of many T gates
interleaved with Clifford gates. This gate-synthesis problem is well understood
for multiqubit gates that do not use any Hadamards. We present an in-depth
analysis of a unified framework that realises one round of distillation and
multiqubit gate synthesis in a single step. We call these synthillation
protocols, and show they lead to a large reduction in resource overheads. This
is because synthillation can implement a general class of circuits using the
same number of T-states as gate synthesis, yet with the benefit of quadratic
error suppression. This general class includes all circuits primarily dominated
by control-control-Z gates, such as adders and modular exponentiation routines
used in Shor's algorithm. Therefore, synthillation removes the need for a
costly round of magic state distillation. We also present several additional
results on the multiqubit gate-synthesis problem. We provide an efficient
algorithm for synthesizing unitaries with the same worst-case resource scaling
as optimal solutions. For the special case of synthesizing
controlled-unitaries, our techniques are not just efficient but exactly
optimal. We observe that the gate-synthesis cost, measured by T-count, is often
strictly subadditive. Numerous explicit applications of our techniques are also
presented.


title: Dissipationless conductance in a topological coaxial cable

abstract:
  We present a dynamical mechanism leading to dissipationless conductance,
whose quantized value is controllable, in a (3+1)-dimensional electronic
system. The mechanism is exemplified by a theory of Weyl fermions coupled to a
Higgs field--also known as an axion insulator. We show that the insertion of an
axial gauge flux can induce vortex lines in the Higgs field, similarly to the
development of vortices in a superconductor upon the insertion of magnetic
flux. We further show that the necessary axial gauge flux can be generated
using Rashba spin-orbit coupling or a magnetic field. Vortex lines in the Higgs
field are known to bind chiral fermionic modes, each of which serves as a
one-way channel for electric charge with conductance $e^2/h$. Combining these
elements, we present a physical picture, the "topological coaxial cable,"
illustrating how the value of the quantized conductance could be controlled in
such an axion insulator.


title: Unifying gate-synthesis and magic state distillation

abstract:
  The leading paradigm for performing computation on quantum memories can be
encapsulated as distill-then-synthesize. Initially, one performs several rounds
of distillation to create high-fidelity magic states that provide one good T
gate, an essential quantum logic gate. Subsequently, gate synthesis
intersperses many T gates with Clifford gates to realise a desired circuit. We
introduce a unified framework that implements one round of distillation and
multi-qubit gate synthesis in a single step. Typically, our method uses the
same number of T gates as conventional synthesis, but with the added benefit of
quadratic error suppression. Because of this, one less round of magic state
distillation needs to be performed, leading to significant resource savings.


title: The Distances of the Galactic Novae

abstract:
  Utilising the unique location of red clump giants on colour-magnitude
diagrams obtained from various near-IR surveys, we derived specific
reddening-distance relations towards 119 Galactic novae for which independent
reddening measurements are available. Using the derived distance-extinction
relation and the independent measurements of reddening we calculated the most
likely distances for each system. We present the details of our distance
measurement technique and the results of this analysis, which yielded the
distances of 73 Galactic novae and allowed us to set lower limits on the
distances of 46 systems. We also present the reddening-distance relations
derived for each nova, which may be useful to analyze the different Galactic
components present in the line of sight.


title:
Variations of the initial mass function in semi-analytical models:
  implications for the mass assembly and the chemical enrichment of galaxies in
  the GAEA model

abstract:
  In this work, we investigate the implications of the Integrated Galaxy-wide
stellar Initial Mass Function (IGIMF) approach in the framework of the
semi-analytic model GAEA (GAlaxy Evolution and Assembly), which features a
detailed treatment of chemical enrichment and stellar feedback. The IGIMF
provides an analytic description of the dependence of the stellar IMF shape on
the rate of star formation in galaxies. We find that our model with a universal
IMF predicts a rather flat [$\alpha$/Fe]-stellar mass relation. The model
assuming the IGIMF, instead, is able to reproduce the observed increase of
$\alpha$-enhancement with stellar mass, in agreement with previous studies.
This is mainly due to the fact that massive galaxies are characterized by
larger star formation rates at high-redshift, leading to stronger
$\alpha$-enhancement with respect to low-mass galaxies. At the same time, the
IGIMF hypothesis does not affect significantly the trend for shorter star
formation timescales for more massive galaxies. We argue that in the IGIMF
scenario the [$\alpha$/Fe] ratios are good tracers of the highest star
formation events. The final stellar masses and mass-to-light-ratio of our model
massive galaxies are larger than those estimated from the synthetic photometry
assuming a universal IMF, providing a self-consistent interpretation of similar
recent results, based on dynamical analysis of local early type galaxies.


title:
Formation of Massive Black Holes in Galactic Nuclei: Runaway Tidal
  Encounters

abstract:
  Nuclear star clusters (NSCs) and supermassive black holes (SMBHs) both
inhabit galactic nuclei, coexisting in a range of bulge masses, but excluding
each other in the largest or smallest galaxies. We propose that the
transformation of NSCs into SMBHs occurs via runaway tidal captures, once NSCs
exceed a certain critical central density and velocity dispersion. The
bottleneck in this process, as with all collisional runaways, is growing the
first e-fold in black hole mass. The growth of a stellar mass black hole past
this bottleneck occurs as tidally captured stars are consumed in repeated
episodes of mass transfer at pericenter. Tidal captures may turn off as a
growth channel once the black hole reaches a mass ~100-1000 solar masses, but
tidal disruption events will continue and appear capable of growing the seed
SMBH to larger sizes. The runaway slows (becomes sub-exponential) once the seed
SMBH consumes the core of its host NSC. While the bulk of the cosmic mass
density in SMBHs is ultimately produced (via the Soltan-Paczynski argument) by
episodic gaseous accretion in very massive galaxies, the smallest SMBHs have
probably grown from strong tidal encounters with NSC stars. SMBH seeds that
grow for a time $t$ entirely through this channel will follow simple power law
relations with the velocity dispersion, $\sigma$, of their host galaxy. In the
simplest regime it is $M_\bullet \sim \sigma^{3/2}\sqrt{M_\star t / G} \sim
10^{6}M_\odot (\sigma / 50~{\rm km~s}^{-1})^{3/2}(t/10^{10}~{\rm yr})^{1/2}$,
but the exponents and prefactor can differ slightly depending on the details of
loss cone refilling. Current tidal disruption event rates predicted from this
mechanism are consistent with observations.


title: Gauge-Invariance and Infrared Divergences in the Luminosity Distance

abstract:
  Measurements of the luminosity distance have played a key role in discovering
the late-time cosmic acceleration. However, when accounting for inhomogeneities
in the Universe, its interpretation has been plagued with infrared divergences
in its theoretical predictions, which are in some cases used to explain the
cosmic acceleration without dark energy. The divergences in most calculations
are artificially removed by imposing an infrared cut-off scale. For the first
time, we show that a gauge-invariant calculation of the luminosity distance is
devoid of such divergences and consistent with the equivalence principle,
eliminating the need to impose a cut-off scale. We present proper numerical
calculations of the luminosity distance using the gauge-invariant expression
and demonstrate that the numerical results with an ad hoc cut-off scale in
previous calculations have negligible systematic errors as long as the cut-off
scale is larger than the horizon scale. We discuss the origin of infrared
divergences and their cancellation in the luminosity distance.


title: Generalised Boundary Terms for Higher Derivative Theories of Gravity

abstract:
  In this paper we wish to find the corresponding Gibbons-Hawking-York term for
the most general quadratic in curvature gravity by using Coframe slicing within
the Arnowitt-Deser-Misner (ADM) decomposition of spacetime in four dimensions.
In order to make sure that the higher derivative gravity is ghost and tachyon
free at a perturbative level, one requires infinite covariant derivatives,
which yields a generalised covariant infinite derivative theory of gravity. We
will be exploring the boundary term for such a covariant infinite derivative
theory of gravity.


title: Particle-vortex duality in topological insulators and superconductors

abstract:
  We investigate the origins and implications of the duality between
topological insulators and topological superconductors in three and four
spacetime dimensions. In the latter, the duality transformation can be made at
the level of the path integral in the standard way, while in three dimensions,
it takes the form of "self-duality in odd dimensions". In this sense, it is
closely related to the particle-vortex duality of planar systems. In
particular, we use this to elaborate on Son's conjecture that a three
dimensional Dirac fermion that can be thought of as the surface mode of a four
dimensional topological insulator is dual to a composite fermion.


title: Estimating strong correlations in optical lattices

abstract:
  Ultra-cold atoms in optical lattices provide one of the most promising
platforms for analog quantum simulations of complex quantum many-body systems.
Large-size systems can now routinely be reached and are already used to probe a
large variety of different physical situations, ranging from quantum phase
transitions to artificial gauge theories. At the same time, measurement
techniques are still limited and full tomography for these systems seems out of
reach. Motivated by this observation, we present a method to directly detect
and quantify to what extent a quantum state deviates from a local Gaussian
description, based on available noise correlation measurements from in-situ and
time-of-flight measurements. This is an indicator of the significance of strong
correlations in ground and thermal states, as Gaussian states are precisely the
ground and thermal states of non-interacting models. We connect our findings,
augmented by numerical tensor network simulations, to notions of equilibration,
disordered systems and the suppression of transport in Anderson insulators.


title: Mixing properties of stochastic quantum Hamiltonians

abstract:
  Random quantum processes play a central role both in the study of fundamental
mixing processes in quantum mechanics related to equilibration, thermalisation
and fast scrambling by black holes, as well as in quantum process design and
quantum information theory. In this work, we present a framework describing the
mixing properties of continuous-time unitary evolutions originating from local
Hamiltonians having time-fluctuating terms, reflecting a Brownian motion on the
unitary group. The induced stochastic time evolution is shown to converge to a
unitary design. As a first main result, we present bounds to the mixing time.
By developing tools in representation theory, we analytically derive an
expression for a local k-th moment operator that is entirely independent of k,
giving rise to approximate unitary k-designs and quantum tensor product
expanders. As a second main result, we introduce tools for proving bounds on
the rate of decoupling from an environment with random quantum processes. By
tying the mathematical description closely with the more established one of
random quantum circuits, we present a unified picture for analysing local
random quantum and classes of Markovian dissipative processes, for which we
also discuss applications.


title:
The impact of the photon PDF and electroweak corrections on $t \bar t$
  distributions

abstract:
  We discuss the impact of EW corrections on differential distributions in
top-quark pair production at the LHC and future hadron colliders, focusing on
the effects of initial-state photons. Performing a calculation at
Next-to-Leading Order QCD+EW accuracy, we investigate in detail the impact of
photon-initiated channels on central values as well as PDF and scale
uncertainties, both at order $\alpha_s\alpha$ and $\alpha_s^2\alpha$. We
present predictions at 13 and 100 TeV, and provide results for the 8 TeV
differential measurements performed by ATLAS and CMS. A thorough comparison of
results obtained with the NNPDF2.3QED and CT14QED PDF sets is performed. While
contributions due to the photon PDF are negligible with CT14QED, this is not
the case for NNPDF2.3QED, where such contributions are sizeable and show large
PDF uncertainties. On the one hand, we show that differential observables in
top-pair production, in particular top-quark and $t\bar t$ rapidities, can be
used to improve the determination of the photon PDF within the NNPDF approach.
On the other hand, with current PDF sets, we demonstrate the necessity of
including EW corrections and photon-induced contributions for a correct
determination of both the central value and the uncertainties of theoretical
predictions.


title: Three conjectures in extremal spectral graph theory

abstract:
  We prove three conjectures regarding the maximization of spectral invariants
over certain families of graphs. Our most difficult result is that the join of
$P_2$ and $P_{n-2}$ is the unique graph of maximum spectral radius over all
planar graphs. This was conjectured by Boots and Royle in 1991 and
independently by Cao and Vince in 1993. Similarly, we prove a conjecture of
Cvetkovi\'c and Rowlinson from 1990 stating that the unique outerplanar graph
of maximum spectral radius is the join of a vertex and $P_{n-1}$. Finally, we
prove a conjecture of Aouchiche et al from 2008 stating that a pineapple graph
is the unique connected graph maximizing the spectral radius minus the average
degree. To prove our theorems, we use the leading eigenvector of a purported
extremal graph to deduce structural properties about that graph. Using this
setup, we give short proofs of several old results: Mantel's Theorem, Stanley's
edge bound and extensions, the K\H{o}vari-S\'os-Tur\'an Theorem applied to
$\mathrm{ex}\left(n, K_{2,t}\right)$, and a partial solution to an old problem
of Erd\H{o}s on making a triangle-free graph bipartite.


title:
Significantly improving stellar mass and radius estimates: A new
  reference function for the \Delta\nu\ scaling relation

abstract:
  The scaling relations between global asteroseismic observables and stellar
properties are widely used to estimate masses and radii of stars exhibiting
solar-like oscillations. Since the mass and radius of the Sun are known
independently, the Sun is commonly used as a reference to scale to. However,
the validity of the scaling relations depends on the homology between the star
under study and the reference star. Solar-like oscillators span a wide range of
masses and metallicities, as well as evolutionary phases. Most of these stars
are therefore not homologous to the Sun. This leads to errors of up to 10% (5%)
in mass (radius) when using the asteroseismic scaling relations with the Sun as
the reference. In this paper we derive a reference function to replace the
solar-reference value used in the large-frequency-separation scaling relation.
Our function is the first that depends on both effective temperature and
metallicity, and is applicable from the end of the main sequence to just above
the bump on the red giant branch. This reference function improves the
estimates of masses and radii determined through scaling relations by a factor
of 2, i.e. allows masses and radii to be recovered with an accuracy of 5% and
2%, respectively.


title:
Unification of Relativistic and Quantum Mechanics from Elementary Cycles
  Theory

abstract:
  In Elementary Cycles theory elementary quantum particles are consistently
described as the manifestation of ultra-fast relativistic spacetime cyclic
dynamics, classical in the essence. The peculiar relativistic geometrodynamics
of Elementary Cycles theory yields de facto a unification of ordinary
relativistic and quantum physics. In particular its classical-relativistic
cyclic dynamics reproduce exactly from classical physics first principles all
the fundamental aspects of Quantum Mechanics, such as all its axioms, the
Feynman path integral, the Dirac quantisation prescription (second
quantisation), quantum dynamics of statistical systems, non-relativistic
quantum mechanics, atomic physics, superconductivity, graphene physics and so
on. Furthermore the theory allows for the explicit derivation of gauge
interactions, without postulating gauge invariance, directly from relativistic
geometrodynamical transformations, in close analogy with the description of
gravitational interaction in general relativity. In this paper we summarise
some of the major achievements, rigorously proven also in several recent
peer-reviewed papers, of this innovative formulation of quantum particle
physics.


title:
A simple table-top demonstration of radiation pressure on a macroscopic
  object

abstract:
  We report a simple demonstration of radiation pressure on a table-top
experiment. Utilizing dynamic force microscopy in ambient environment, the
resonant motion of a cm-sized cantilever driven by an amplitude-modulated diode
laser is directly observed. Our versatile setup involves a host of exciting
techniques that are relevant in precision force measurements and represents an
ideal experiment in the undergraduate laboratory.


title: Holographic Entanglement Entropy in NMG

abstract:
  In this paper, we show that a higher derivative theory, such as New Massive
Gravity, allows the existence of new entangling surfaces with non-zero
extrinsic curvature. We perform the analysis for Lifshitz and Warped $AdS$
space times, revealing the role of the higher derivative contributions in the
calculation of the holographic entanglement entropy. Finally, as an outcome of
our holographic analysis we briefly comment on the dual boundary theory.


title: The p-adic Hodge decomposition according to Beilinson

abstract: A detailed presentation of Beilinson's approach to p-adic Hodge theory.


title: Giant photon gain in large-scale quantum dot circuit-QED systems

abstract:
  Motivated by recent experiments on the generation of coherent light in
engineered hybrid quantum systems, we investigate gain in a microwave photonic
cavity coupled to quantum dot structures, and develop concrete directions for
achieving a giant amplification in photon transmission. We propose two
architectures for scaling up the electronic gain medium: (i) $N$ double quantum
dot systems (N-DQD), (ii) $M$ quantum dots arranged in series akin to a quantum
cascade laser setup. In both setups, the fermionic reservoirs are voltage
biased, and the quantum dots are coupled to a single-mode cavity. Optical
amplification is explained based on a sum rule for the transmission function,
and it is determined by an intricate competition between two different
processes: charge density response in the gain medium, and cavity losses to
input and output ports. The same design principle is also responsible for the
corresponding giant amplification in other photonic observables, mean photon
number and emission spectrum, thereby realizing a quantum device that behaves
as a giant microwave amplifier.


title:
Neutron star crust cooling in KS 1731-260: the influence of accretion
  outburst variability on the crustal temperature evolution

abstract:
  Using a theoretical model, we track the thermal evolution of a cooling
neutron star crust after an accretion induced heating period with the goal of
constraining the crustal parameters. We present for the first time a crust
cooling model $-\text{ } NSCool\text{ } -$ that takes into account detailed
variability during the full outburst based on the observed light curve. We
apply our model to KS 1731-260. The source was in outburst for $\sim$12 years
during which it was observed to undergo variations on both long (years) and
short (days-weeks) timescales. Our results show that KS 1731-260 does not reach
a steady state profile during the outburst due to fluctuations in the derived
accretion rate. Additionally, long time-scale outburst variability mildly
affects the complete crust cooling phase, while variations in the final months
of the outburst strongly influence the first $\sim$40 days of the calculated
cooling curve. We discuss the consequences for estimates of the neutron star
crust parameters, and argue that detailed modelling of the final phase of the
outburst is key to constraining the origin of the shallow heat source.


title: Preliminaries of a Space Situational Awareness Ontology

abstract:
  Space situational awareness (SSA) is vital for international safety and
security, and the future of space travel. By improving SSA data-sharing we
improve global SSA. Computational ontology may provide one means toward that
goal. This paper develops the ontology of the SSA domain and takes steps in the
creation of the space situational awareness ontology. Ontology objectives,
requirements and desiderata are outlined; and both the SSA domain and the
discipline of ontology are described. The purposes of the ontology include:
exploring the potential for ontology development and engineering to (i)
represent SSA data, general domain knowledge, objects and relationships (ii)
annotate and express the meaning of that data, and (iii) foster SSA
data-exchange and integration among SSA actors, orbital debris databases, space
object catalogs and other SSA data repositories. By improving SSA via data- and
knowledge-sharing, we can (iv) expand our scientific knowledge of the space
environment, (v) advance our capacity for planetary defense from near-Earth
objects, and (vi) ensure the future of safe space flight for generations to
come.


title:
Further Kernelization of Proper Interval Vertex Deletion: New
  Observations and Refined Analysis

abstract:
  In the Proper Interval Vertex Deletion problem (PIVD for short), we are given
a graph $G$ and an integer parameter $k>0$, and the question is whether there
are at most $k$ vertices in $G$ whose removal results in a proper interval
graph. It is known that the PIVD problem is fixed-parameter tractable and
admits a polynomial but "unreasonably" large kernel of $O(k^{53})$ vertices. A
natural question is whether the problem admits a polynomial kernel of
"reasonable" size. In this paper, we answer this question by deriving an
$O(k^7)$-vertex kernel for the PIVD problem. Our kernelization is based on
several new observations and a refined analysis of the kernelization.


title: Stellar Evidence that the Solar Dynamo may be in Transition

abstract:
  Precise photometry from the Kepler space telescope allows not only the
measurement of rotation in solar-type field stars, but also the determination
of reliable masses and ages from asteroseismology. These critical data have
recently provided the first opportunity to calibrate rotation-age relations for
stars older than the Sun. The evolutionary picture that emerges is surprising:
beyond middle-age the efficiency of magnetic braking is dramatically reduced,
implying a fundamental change in angular momentum loss beyond a critical Rossby
number (Ro~2). We compile published chromospheric activity measurements for the
sample of Kepler asteroseismic targets that were used to establish the new
rotation-age relations. We use these data along with a sample of well
characterized solar analogs from the Mount Wilson HK survey to develop a
qualitative scenario connecting the evolution of chromospheric activity to a
fundamental shift in the character of differential rotation. We conclude that
the Sun may be in a transitional evolutionary phase, and that its magnetic
cycle might represent a special case of stellar dynamo theory.


title:
Supplemental Material for Comment on "Excitons in Molecular Aggregates
  with Levy Disorder: Anomalous Localization and Exchange Broadening of Optical
  Spectra", Phys.Rev.Lett. 109, 259701 (https://arxiv.org/abs/1208.2779)

abstract:
  In their Letter "Excitons in Molecular Aggregates with Levy Disorder:
Anomalous Localization and Exchange Broadening of Optical Spectra", Eisfeld et
al. predicted the existence of exchange broadening and blue-shift of the
absorption band and a non-universal disorder scaling of the localisation length
of absorption band excitons in J-aggregates with heavy-tailed disorder, which
they contrasted with the previously analysed Gaussian and Lorentzian case. The
observations were explained by another localisation mechanism, the chain
segmentation by outliers in heavy tails of the disorder distribution. We argue
that the previously known theory does not break down and consequently
anticipates the properties of the absorption band investigated in the commented
work.


title: Stochastic difference equations with the Allee effect

abstract:
  For a truncated stochastically perturbed equation $x_{n+1}=\max\{
f(x_n)+l\chi_{n+1}, 0 \}$ with $f(x)<x$ on $(0,m)$, which corresponds to the
Allee effect, we observe that for very small perturbation amplitude $l$, the
eventual behavior is similar to a non-perturbed case: there is extinction for
small initial values in $(0,m-\varepsilon)$ and persistence for $x_0 \in
(m+\delta, H]$ for some $H$ satisfying $H>f(H)>m$. As the amplitude grows, an
interval $(m-\varepsilon, m+\delta)$ of initial values arises and expands, such
that with a certain probability, $x_n$ sustains in $[m, H]$, and possibly
eventually gets into the interval $(0,m-\varepsilon)$, with a positive
probability. Lower estimates for these probabilities are presented. If $H$ is
large enough, as the amplitude of perturbations grows, the Allee effect
disappears: a solution persists for any positive initial value.


title: A near-stationary subspace for ridge approximation

abstract:
  Response surfaces are common surrogates for expensive computer simulations in
engineering analysis. However, the cost of fitting an accurate response surface
increases exponentially as the number of model inputs increases, which leaves
response surface construction intractable for high-dimensional, nonlinear
models. We describe ridge approximation for fitting response surfaces in
several variables. A ridge function is constant along several directions in its
domain, so fitting occurs on the coordinates of a low-dimensional subspace of
the input space. We review essential theory for ridge approximation---e.g., the
best mean-squared approximation and an optimal low-dimensional subspace---and
we prove that the gradient-based active subspace is near-stationary for the
least-squares problem that defines an optimal subspace. Motivated by the
theory, we propose a computational heuristic that uses an estimated active
subspace as an initial guess for a ridge approximation fitting problem. We show
a simple example where the heuristic fails, which reveals a type of function
for which the proposed approach is inappropriate. We then propose a simple
alternating heuristic for fitting a ridge function, and we demonstrate the
effectiveness of the active subspace initial guess applied to an airfoil model
of drag as a function of its 18 shape parameters.


title: Consistency and Trust in Peer Data Exchange Systems

abstract:
  We propose and investigate a semantics for "peer data exchange systems" where
different peers are related by data exchange constraints and trust
relationships. These two elements plus the data at the peers' sites and their
local integrity constraints are made compatible via a semantics that
characterizes sets of "solution instances" for the peers. They are the intended
-possibly virtual- instances for a peer that are obtained through a data repair
semantics that we introduce and investigate. The semantically correct answers
from a peer to a query, the so-called "peer consistent answers", are defined as
those answers that are invariant under all its different solution instances. We
show that solution instances can be specified as the models of logic programs
with a stable model semantics. The repair semantics is based on null values as
used in SQL databases, and is also of independent interest for repairs of
single databases with respect to integrity constraints.


title:
High harmonic interferometry of the Lorentz force in strong mid-infrared
  laser fields

abstract:
  The interaction of intense mid-infrared laser fields with atoms and molecules
leads to a range of new opportunities, from the production of bright, coherent
radiation in the soft x-ray range to imaging molecular structures and dynamics
with attosecond temporal and sub-angstrom spatial resolution. However, all
these effects, which rely on laser-driven recollision of an electron removed by
the strong laser field and the parent ion, suffer from the rapidly increasing
role of the magnetic field component of the driving pulse: the associated
Lorentz force pushes the electrons off course in their excursion and suppresses
all recollision-based processes, including high harmonic generation, elastic
and inelastic scattering. Here we show how the use of two non-collinear beams
with opposite circular polarizations produces a forwards ellipticity which can
be used to monitor, control, and cancel the effect of the Lorentz force. This
arrangement can thus be used to re-enable recollision-based phenomena in
regimes beyond the long-wavelength breakdown of the dipole approximation, and
it can be used to observe this breakdown in high-harmonic generation using
currently-available light sources.


title: Inference of Causal Information Flow in Collective Animal Behavior

abstract:
  Understanding and even defining what constitutes animal interactions remains
a challenging problem. Correlational tools may be inappropriate for detecting
communication between a set of many agents exhibiting nonlinear behavior. A
different approach is to define coordinated motions in terms of an information
theoretic channel of direct causal information flow. In this work, we consider
time series data obtained by an experimental protocol of optical tracking of
the insect species Chironomus riparius. The data constitute reconstructed 3-D
spatial trajectories of the insects' flight trajectories and kinematics. We
present an application of the optimal causation entropy (oCSE) principle to
identify direct causal relationships or information channels among the insects.
The collection of channels inferred by oCSE describes a network of information
flow within the swarm. We find that information channels with a long spatial
range are more common than expected under the assumption that causal
information flows should be spatially localized. The tools developed herein are
general and applicable to the inference and study of intercommunication
networks in a wide variety of natural settings.


title: A Decomposable Attention Model for Natural Language Inference

abstract:
  We propose a simple neural architecture for natural language inference. Our
approach uses attention to decompose the problem into subproblems that can be
solved separately, thus making it trivially parallelizable. On the Stanford
Natural Language Inference (SNLI) dataset, we obtain state-of-the-art results
with almost an order of magnitude fewer parameters than previous work and
without relying on any word-order information. Adding intra-sentence attention
that takes a minimum amount of order into account yields further improvements.


title: HR-Cosmos: Kinematics of Star-Forming Galaxies at z $\sim$ 0.9

abstract:
  We present the kinematic analysis of a sub-sample of 82 galaxies at
$\mathrm{0.75<z<1.2}$ from our new survey HR-COSMOS aimed to obtain the first
statistical study on the kinematics of star-forming galaxies in the treasury
COSMOS field at $\mathrm{0<z<1.2}$. We observed $\sim\,$766 emission line
galaxies using the multi-slit spectrograph ESO-VLT/VIMOS in high-resolution
mode (R=2500). To better extract galaxy kinematics, VIMOS spectral slits have
been carefully tilted along the major axis orientation of the galaxies, making
use of the position angle measurements from the high spatial resolution ACS/HST
COSMOS images. We constrained the kinematics of the sub-sample at $0.75<z<1.2$
by creating high resolution semi-analytical models. We established the
stellar-mass Tully-Fisher relation at $z\simeq 0.9$ with high-quality stellar
mass measurements derived using the latest COSMOS photometric catalog, which
includes the latest data releases of UltraVISTA and Spitzer. In doubling the
sample at these redshifts compared with the literature, we estimated the
relation without setting its slope, and found it consistent with previous
studies in other deep extragalactic fields assuming no significant evolution of
the relation with redshift at $z\lesssim1$. We computed dynamical masses within
the radius R$_{2.2}$ and found a median stellar-to-dynamical mass fraction
equal to 0.2 (assuming Chabrier IMF), which implies a contribution of gas and
dark matter masses of 80% of the total mass within R$_{2.2}$, in agreement with
recent integral field spectroscopy surveys. We find no dependence of the
stellar-mass Tully-Fisher relation with environment probing up to group scale
masses. This study shows that multi-slit galaxy surveys remain a powerful tool
to derive kinematics for large numbers of galaxies at both high and low
redshift.


title: A generalized formulation for vehicle routing problems

abstract:
  Different types of formulations are proposed in the literature to model
vehicle routing problems. Currently, the most used ones can be fitted into two
classes, namely vehicle flow formulations and set partitioning formulations.
These types of formulations differ from each other not only due to their
variables and constraints but also due to their main features. Vehicle flow
formulations have the advantage of being compact models, so general-purpose
optimization packages can be used to straightforwardly solve them. However,
they typically show weak linear relaxations and have a large number of
constraints. Branch-and-cut methods based on specialized valid inequalities can
also be devised to solve these formulations, but they have not shown to be
effective for large-scale instances. On the other hand, set partitioning
formulations have stronger linear relaxations, but requires the implementation
of sophisticate techniques such as column generation and specialized
branch-and-price methods. Due to all these reasons, so far it is has been
recognized in the vehicle routing community that these two types of
formulations are rather different. In this paper, we show that they are
actually strongly related as they correspond to special cases of a generalized
formulation of vehicle routing problems.


title:
A brief introduction to the model microswimmer {\it Chlamydomonas
  reinhardtii}

abstract:
  The unicellular biflagellate green alga {\it Chlamydomonas reinhardtii} has
been an important model system in biology for decades, and in recent years it
has started to attract growing attention also within the biophysics community.
Here we provide a concise review of some of the aspects of {\it Chlamydomonas}
biology and biophysics most immediately relevant to physicists that might be
interested in starting to work with this versatile microorganism.


title: Forecasting and skipping to Reduce Transmission Energy in WSN

abstract:
  This paper deals with the improvement of energy efficiency in wireless sensor
networks (WSN).Taking into consideration the power saving problem which is of
crucial importance when the sensors are supplied by a limited power source,
this paper proposes a method that optimizes as much as possible the
transmission power of the sensors. Under the assumption of perfect channel
between the Base Station (BS) and the Sensor Nodes (SN's) and with sufficient
power resources at the BS, transferring the effort of transmission power to the
BS will not be a peculiar issue. This paper proposes a method that reduces the
transmitted data at the SN's and compensate this by requesting the variance of
the measured value form predicted values. Furthermore, a request management
algorithm (RMA) is developed to reduce the amount of requested data based on
consecutive successive predictions. The result of this method reveals a major
impact on reducing the transmission power at the SN's. Keywords: Wireless
Sensor Networks, Data Reduction, Time Series Forecasting, Artificial Neural
Networks.


title: From geometry to non-geometry via T-duality

abstract:
  Reconsideration of the T-duality of the open string allows us to introduce
some geometric features in non-geometric theories. First, we have found what
symmetry is T-dual to the local gauge transformations. It includes
transformations of background fields but does not include transformations of
the coordinates. According to this we have introduced a new, up to now missing
term, with additional gauge field $A^D_i$ (D denotes components with Dirichlet
boundary conditions). It compensates non-fulfilment of the invariance under
such transformations on the end-points of an open string, and the standard
gauge field $A^N_a$ (N denotes components with Neumann boundary conditions)
compensates non-fulfilment of the gauge invariance. Using a generalized
procedure we will perform T-duality of vector fields linear in coordinates. We
show that gauge fields $A^N_a$ and $A^D_i$ are T-dual to ${}^\star A_D^a$ and
${}^\star A_N^i$ respectively.
  We introduce the field strength of T-dual non-geometric theories as
derivatives of T-dual gauge fields along both T-dual variable $y_\mu$ and its
double ${\tilde y}_\mu$. This definition allows us to obtain gauge
transformation of non-geometric theories which leaves the T-dual field strength
invariant. Therefore, we introduce some new features of non-geometric theories
where field strength has both antisymmetric and symmetric parts. This allows us
to define new kinds of truly non-geometric theories.


title:
Stabilisation of difference equations with noisy prediction-based
  control

abstract:
  We consider the influence of stochastic perturbations on stability of a
unique positive equilibrium of a difference equation subject to
prediction-based control. These perturbations may be multiplicative
$$x_{n+1}=f(x_n)-\left( \alpha + l\xi_{n+1} \right) (f(x_n)-x_n), \quad n=0, 1,
\dots$$ if they arise from stochastic variation of the control parameter, or
additive $$x_{n+1}=f(x_n)-\alpha(f(x_n)-x_n) +l\xi_{n+1}, \quad n=0, 1, \dots
$$ if they reflect the presence of systemic noise.
  We begin by relaxing the control parameter in the deterministic equation, and
deriving a range of values for the parameter over which all solutions
eventually enter an invariant interval. Then, by allowing the variation to be
stochastic, we derive sufficient conditions (less restrictive than known ones
for the unperturbed equation) under which the positive equilibrium will be
globally a.s. asymptotically stable:i.e. the presence of noise improves the
known effectiveness of prediction-based control. Finally, we show that systemic
noise has a "blurring" effect on the positive equilibrium, which can be made
arbitrarily small by controlling the noise intensity. Numerical examples
illustrate our results.


title:
Relativistic mechanical-thermodynamical formalism -- description of
  inelastic collisions

abstract:
  We present a relativistic formalism inspired on the Minkowski four-vectors
that also includes conservation laws such as the first law of thermodynamics.
It remains close to the relativistic four-vector formalism developed for a
single particle, but it is also related to the classical treatment of problems
that imperatively require both the Newton's second law and the energy
conservation law. We apply the developed formalism to inelastic collisions to
better show how it works.


title:
Intra-Slot Interference Cancellation for Collision Resolution in
  Irregular Repetition Slotted ALOHA

abstract:
  ALOHA-type protocols became a popular solution for distributed and
uncoordinated multiple random access in wireless networks. However, such
distributed operation of the Medium Access Control (MAC) layer leads to
sub-optimal utilization of the shared channel. One of the reasons is the
occurrence of collisions when more than one packet is transmitted at the same
time. These packets cannot be decoded and retransmissions are necessary.
However, it has been recently shown that it is possible to apply signal
processing techniques with these collided packets so that useful information
can be decoded. This was recently proposed in the Irregular Repetition Slotted
ALOHA (IRSA), achieving a throughput $T \simeq 0.97$ for very large MAC frame
lengths as long as the number of active users is smaller than the number of
slots per frame. In this paper, we extend the operation of IRSA with i) an
iterative physical layer decoding processing that exploits the capture effect
and ii) a Successive Interference Cancellation (SIC) processing at the
slot-level, named intra-slot SIC, to decode more than one colliding packet per
slot. We evaluate the performance of the proposed scheme, referred to as
Extended IRSA (E-IRSA), in terms of throughput and channel capacity.
Computer-based simulation results show that E-IRSA protocol allows to reach the
maximum theoretical achievable throughput even in scenarios where the number of
active users is higher than the number of slots per frame. Results also show
that E-IRSA protocol significantly improves the performance even for small MAC
frame lengths used in practical scenarios.


title: Linear versus set valued Kronecker representations

abstract:
  A set valued representation of the Kronecker quiver is nothing but a quiver.
We apply the forgetful functor from vector spaces to sets and compare linear
with set valued representations of the Kronecker quiver.


title:
Optimizing Point-to-Multipoint Transmissions in High Speed Packet Access
  Networks

abstract:
  In this paper an innovative Radio Resource Management (RRM) algorithm is
proposed with the purpose of increasing High Speed Packet Access (HSPA)
performances, in terms of system capacity and service quality, when the
Multimedia Broadcast Multicast Services (MBMS) is supplied. The proposed RRM
algorithm exploits channel quality indications to set up point-to-multipoint
connections to subgroups of multicast users and to select the proper modulation
and coding schemes on the downlink. The number of subgroups is determined
through an optimization technique that also takes into account the user
satisfaction. An exhaustive simulation campaign is conducted to compare the
proposed algorithm with the most promising approaches in the literature.
Comparisons aim to assess the capability of the proposed RRM algorithm to
efficiently manage group oriented services by providing an increment in terms
of user satisfaction.


title:
On the Distribution of the Number of Copies of Weakly Connected Digraphs
  in Random $k$NN Digraphs

abstract:
  In a digraph with $n$ vertices, a minuscule construct is a subdigraph with
$m<<n$ vertices. We study the number of copies of a minuscule constructs in $k$
nearest neighbor ($k$NN) digraph of the data from a random point process in
$\mathbb{R}^d$. Based on the asymptotic theory for functionals of point sets
under homogeneous Poisson process and binomial point process, we provide a
general result for the asymptotic behavior of the number of minuscule
constructs and as corollaries, we obtain asymptotic results for the number of
vertices with fixed indegree, the number of shared $k$NN pairs and the number
of reflexive $k$NN's in a $k$NN digraph.


title: Light quark mass differences in the $\pi^0 - \eta - \eta'$ system

abstract:
  A generalized 3 flavor Nambu-Jona--Lasinio Lagrangian including the explicit
chiral symmetry breaking interactions which contribute at the same order in the
large $1/N_c$ counting as the $U_A(1)$ 't Hooft flavor determinant is
considered to obtain the mixing angles in the $\pi^0-\eta-\eta'$ system and
related current quark mass ratios in close agreement with phenomenological
values. At the same time an accurate ordering and magnitude of the splitting of
states in the low lying pseudoscalar nonet is obtained.


title: Minimum-Information LQG Control - Part I: Memoryless Controllers

abstract:
  With the increased demand for power efficiency in feedback-control systems,
communication is becoming a limiting factor, raising the need to trade off the
external cost that they incur with the capacity of the controller's
communication channels. With a proper design of the channels, this translates
into a sequential rate-distortion problem, where we minimize the rate of
information required for the controller's operation under a constraint on its
external cost. Memoryless controllers are of particular interest both for the
simplicity and frugality of their implementation and as a basis for studying
more complex controllers. In this paper we present the optimality principle for
memoryless linear controllers that utilize minimal information rates to achieve
a guaranteed external-cost level. We also study the interesting and useful
phenomenology of the optimal controller, such as the principled reduction of
its order.


title: Minimum-Information LQG Control - Part II: Retentive Controllers

abstract:
  Retentive (memory-utilizing) sensing-acting agents may operate under
limitations on the communication between their sensing, memory and acting
components, requiring them to trade off the external cost that they incur with
the capacity of their communication channels. In this paper we formulate this
problem as a sequential rate-distortion problem of minimizing the rate of
information required for the controller's operation under a constraint on its
external cost. We reduce this bounded retentive control problem to the
memoryless one, studied in Part I of this work, by viewing the memory reader as
one more sensor and the memory writer as one more actuator. We further
investigate the structure of the resulting optimal solution and demonstrate its
interesting phenomenology.


title:
Donaldson-Thomas Transformation of Double Bruhat Cells in General Linear
  Groups

abstract:
  Kontsevich and Soibelman defined the Donaldson-Thomas invariants of a 3d
Calabi-Yau category with a stability condition. Any cluster variety can produce
an example of such a category, whose corresponding Donaldson-Thomas invariants
are encoded by a special formal automorphism of the cluster variety, known as
the Donaldson-Thomas transformation.
  In this paper we prove a conjecture of Goncharov and Shen in the case of
$\mathrm{GL}_n$, which describes the Donaldson-Thomas transformation of the
double quotient of the double Bruhat cells $H \backslash \mathrm{GL}_n^{u,v}/H$
where $H$ is a maximal torus, as a certain explicit cluster transformation
related to Fomin-Zelevinsky's twist map. Our result, combined with the work of
Gross, Hacking, Keel, and Kontsevich, proves the duality conjecture of Fock and
Goncharov in the case of $H\backslash \mathrm{GL}_n^{u,v}/H$.


title: Assisted Energy Management in Smart Microgrids

abstract:
  Demand response provides utilities with a mechanism to share with end users
the stochasticity resulting from the use of renewable sources. Pricing is
accordingly used to reflect energy availability, to allocate such a limited
resource to those loads that value it most. However, the strictly competitive
mechanism can result in service interruption in presence of competing demand.
To solve this issue we investigate on the use of forward contracts, i.e.,
service level agreements priced to reflect the expectation of future supply and
demand curves. Given the limited resources of microgrids, service interruption
is an opposite objective to the one of service availability. We firstly design
policy-based brokers and identify then a learning broker based on artificial
neural networks. We show the latter being progressively minimizing the
reimbursement costs and maximizing the overall profit.


title: Intrinsic Random Functions on the sphere

abstract:
  Spatial stochastic processes that are modeled over the entire Earth's surface
require statistical approaches that directly consider the spherical domain.
Here, we extend the notion of intrinsic random functions (IRF) to model
non-stationary processes on the sphere and show that low-frequency truncation
plays an essential role. Then, the universal kriging formula on the sphere is
derived. We show that all of these developments can be presented through the
theory of reproducing kernel Hilbert space. In addition, the link between
universal kriging and splines is carefully investigated, whereby we show that
thin-plate splines are non-applicable for surface fitting on the sphere.


title:
Nanoporous monolithic microsphere arrays have anti-adhesive properties
  independent of humidity

abstract:
  Bioinspired artificial surfaces with tailored adhesive properties have
attracted significant interest. While fibrillar adhesive pads mimicking gecko
feet are optimized for strong reversible adhesion, monolithic microsphere
arrays mimicking the slippery zone of the pitchers of carnivorous plants of the
genus Nepenthes show anti-adhesive properties even against tacky counterpart
surfaces. In contrast to the influence of topography, the influence of relative
humidity (RH) on adhesion has been widely neglected. Some previous works deal
with the influence of RH on the adhesive performance of fibrillar adhesive
pads. Commonly, humidity-induced softening of the fibrils enhances adhesion.
However, little is known on the influence of RH on solid anti-adhesive
surfaces. We prepared polymeric nanoporous monolithic microsphere arrays
(NMMAs) with microsphere diameters of a few 10 {\mu}m to test their
anti-adhesive properties at RHs of 2 % and 90 %. Despite the presence of
continuous nanopore systems through which the inner nanopore walls were
accessible to humid air, the topography-induced anti-adhesive properties of
NMMAs on tacky counterpart surfaces were retained even at RH = 90 %. This
RH-independent robustness of the anti-adhesive properties of NMMAs
significantly contrasts the adhesion enhancement by humidity-induced softening
on nanoporous fibrillar adhesive pads made of the same material.


title: Spin Nernst Effect of Magnons in Collinear Antiferromagnets

abstract:
  In a collinear antiferromagnet with easy-axis anisotropy, symmetry guarantees
that the spin wave modes are doubly degenerate. The two modes carry opposite
spin angular momentum and exhibit opposite chirality. Using a honeycomb
antiferromagnet in the presence of the Dzyaloshinskii-Moriya interaction, we
show that a longitudinal temperature gradient can drive the two modes to
opposite transverse directions, realizing a spin Nernst effect of magnons with
vanishing thermal Hall current. We find that magnons around the {\Gamma}-point
and the K-point contribute oppositely to the transverse spin transport, and
their competition leads to a sign change of the spin Nernst coefficient at
finite temperature. Possible material candidates are discussed.


title:
Content-Based Interference Management for Video Transmission in D2D
  Communications Underlaying LTE

abstract:
  A novel interference management approach is proposed for modern communication
scenarios, where multiple applications and networks coexist on the same channel
resource. The leading principle behind the proposed approach is that the
interference level should be adapted to the content being transmitted by the
data links to maximize the amount of delivered information. A network setting
is considered where Device-to-Device (D2D) communications underlay a Long Term
Evolution (LTE) link uploading video content to the network infrastructure. For
this scenario, an optimization problem is formulated aiming at the maximization
of the D2D throughput under a constraint on the Peak Signal-to-Noise-Ratio of
the video data stream. The resulting optimal policy focuses interference on
specific packets within the video stream, and significantly increases the
throughput achieved by the D2D link compared to an undifferentiated
interference strategy. The optimal strategy is applied to a real-world video
streaming application to further demonstrate the performance gain.


title:
Spin-Wave and Electromagnon Dispersions in Multiferroic MnWO4 as
  Observed by Neutron Spectroscopy: Isotropic Heisenberg Exchange versus
  Anisotropic Dzyaloshinskii-Moriya Interaction

abstract:
  High resolution inelastic neutron scattering reveals that the elementary
magnetic excitations in multiferroic MnWO4 consist of low energy dispersive
electromagnons in addition to the well-known spin-wave excitations. The latter
can well be modeled by a Heisenberg Hamiltonian with magnetic exchange coupling
extending to the 12th nearest neighbor. They exhibit a spin-wave gap of 0.61(1)
meV. Two electromagnon branches appear at lower energies of 0.07(1) meV and
0.45(1) meV at the zone center. They reflect the dynamic magnetoelectric
coupling and persist in both, the collinear magnetic and paraelectric AF1
phase, and the spin spiral ferroelectric AF2 phase. These excitations are
associated with the Dzyaloshinskii-Moriya exchange interaction, which is
significant due to the rather large spin-orbit coupling.


title: One more proof of the Abhyankar-Moh-Suzuki theorem

abstract: We extract the Abhyankar-Moh-Suzuki theorem from the Lin-Zaidenberg theorem.


title: The Third Swift Burst Alert Telescope Gamma-Ray Burst Catalog

abstract:
  To date, the Burst Alert Telescope (BAT) onboard Swift has detected ~ 1000
gamma-ray bursts (GRBs), of which ~ 360 GRBs have redshift measurements,
ranging from z = 0.03 to z = 9.38. We present the analyses of the BAT-detected
GRBs for the past ~ 11 years up through GRB151027B. We report summaries of both
the temporal and spectral analyses of the GRB characteristics using event data
(i.e., data for each photon within approximately 250 s before and 950 s after
the BAT trigger time), and discuss the instrumental sensitivity and selection
effects of GRB detections. We also explore the GRB properties with redshift
when possible. The result summaries and data products are available at
http://swift.gsfc.nasa.gov/results/batgrbcat/index.html . In addition, we
perform searches for GRB emissions before or after the event data using the BAT
survey data. We estimate the false detection rate to be only one false
detection in this sample. There are 15 ultra-long GRBs (~ 2% of the BAT GRBs)
in this search with confirmed emission beyond ~ 1000 s of event data, and only
two GRBs (GRB100316D and GRB101024A) with detections in the survey data prior
to the starting of event data.
  (Some figures shown here are in lower resolution due to the size limit on
arXiv. The full resolution version can be found at
http://swift.gsfc.nasa.gov/results/batgrbcat/3rdBATcatalog.pdf )


title:
Reliable Querying of Very Large, Fast Moving and Noisy Predicted
  Interaction Data using Hierarchical Crowd Curation

abstract:
  The abundance of predicted and mined but uncertain biological data show huge
needs for massive, efficient and scalable curation efforts. The human expertise
warranted by any successful curation enterprize is often economically
prohibitive especially for speculative end user queries that may not ultimately
bear fruit. So the challenge remains in devising a low cost engine capable of
delivering fast but tentative annotation and curation of a set of data items
that can be authoritatively validated by experts later demanding significantly
small investment. The aim thus is to make a large volume of predicted data
available for use as early as possible with an acceptable degree of confidence
in their accuracy while the curation continues. In this paper, we present a
novel approach to annotation and curation of biological database contents using
crowd computing. The technical contribution is in the identification and
management of trust of mechanical turks, and support for ad hoc declarative
queries, both of which are leveraged to support reliable analytics using noisy
predicted interactions.


title: Stellar populations in the Carina region: The Galactic plane at l = 291

abstract:
  Previous studies of the Carina region have revealed its complexity and
richness as well as a significant number of early-type stars. In many cases,
these studies only concentrated on the central region or were not homogeneous.
This latter aspect, in particular, is crucial because very different ages and
distances for key clusters have been claimed in recent years. The aim of this
work is to study in detail an area of the Galactic plane in Carina. We analyze
the properties of different stellar populations and focus on a sample of open
clusters and their population of YSOs and highly reddened early stars. We also
studied the stellar mass distribution in these clusters and the possible
scenario of their formation. Finally, we outline the Galactic spiral structure
in this direction. We obtained photometric data for six young open clusters
located in Carina at l = 291, and their adjacent stellar fields, which we
complemented with spectroscopic observations of a few selected targets. We also
culled additional information from the literature. Our results provide more
reliable estimates of distances, color excesses, masses, and ages of the
stellar populations in this direction. We estimate the basic parameters of the
studied clusters and find that they identify two overdensities of young stellar
populations. We find evidence of PMS populations inside them, with an apparent
coeval stellar formation in the most conspicuous clusters. We also discuss
apparent age and distance gradients in the direction NW-SE. We study the mass
distributions of several clusters in the region. They consistently show a
canonical IMF slope. We discover and characterise an abnormally reddened
massive stellar population. Spectroscopic observations of ten stars of this
latter population show that all selected targets were massive OB stars. Their
location is consistent with the position of the Car-Sag spiral arm.


title: Beyond Zipf's Law: The Lavalette Rank Function and its Properties

abstract:
  Although Zipf's law is widespread in natural and social data, one often
encounters situations where one or both ends of the ranked data deviate from
the power-law function. Previously we proposed the Beta rank function to
improve the fitting of data which does not follow a perfect Zipf's law. Here we
show that when the two parameters in the Beta rank function have the same
value, the Lavalette rank function, the probability density function can be
derived analytically. We also show both computationally and analytically that
Lavalette distribution is approximately equal, though not identical, to the
lognormal distribution. We illustrate the utility of Lavalette rank function in
several datasets. We also address three analysis issues on the statistical
testing of Lavalette fitting function, comparison between Zipf's law and
lognormal distribution through Lavalette function, and comparison between
lognormal distribution and Lavalette distribution.


title: Advanced broad-band solid-state supermirror polarizers for cold neutrons

abstract:
  An ideal solid-state supermirror (SM) neutron polarizer assumes total
reflection of neutrons from the SM coating for one spin-component and total
absorption for the other, thus providing a perfectly polarized neutron beam at
the exit. However, in practice, the substrate's neutron-nucleai optical
potential does not match perfectly that for spin-down neutrons in the SM. For a
positive step in the optical potential (as in a Fe/SiN(x) SM on Si substrate),
this mismatch results in spin-independent total reflection for neutrons with
small momentum transfer Q, limiting the useful neutron bandwidth in the low-Q
region. To overcome this limitation, we propose to replace Si single-crystal
substrates by media with higher optical potential than that for spin-down
neutrons in the SM ferromagnetic layers. We found single-crystal sapphire and
single-crystal quartz as good candidates for solid-state Fe/SiN(x) SM
polarizers. To verify this idea, we coated a thick plate of single-crystal
sapphire with a m=2.4 Fe/SiN(x) SM. At the T3 instrument at the ILL, we
measured the spin-up and spin-down reflectivity curves with 7.5 A neutrons
incident from the substrate to the interface between the substrate and the SM
coating. The results of this experimental test were in excellent agreement with
our expectations: the bandwidth of high polarizing power extended significantly
into the low-Q region. This finding, together with the possibility to apply a
strong magnetizing field, opens a new road to produce high-efficient
solid-state SM polarizers with an extended neutron wavelength bandwidth and
near-to-perfect polarizing power.


title: Bavard's duality theorem on conjugation-invariant norms

abstract:
  Bavard proved a duality theorem between commutator length and quasimorphisms.
Burago, Ivanov and Polterovich introduced the notion of a conjugation-invariant
norm which is a generalization of commutator length. Entov and Polterovich
proved that Oh-Schwarz spectral invariants are subset-controlled quasimorphisms
which are geralizations of quasimorphisms. In the present paper, we prove a
Bavard-type duality theorem between conjugation-invariant (pseudo-)norms and
subset-controlled quasimorphisms on stable groups. %We also give an application
of its generalization to symplectic geometry related to Entov-Polterovich's
theory on heavy subsets. We also pose a generalization of our main theorem and
prove that "stably non-displaceable subsets of symplectic manifolds are heavy"
in a rough sense if that generalization holds.


title:
Efficient Deployment of Multiple Unmanned Aerial Vehicles for Optimal
  Wireless Coverage

abstract:
  In this paper, the efficient deployment of multiple unmanned aerial vehicles
(UAVs) with directional antennas acting as wireless base stations that provide
coverage for ground users is analyzed. First, the downlink coverage probability
for UAVs as a function of the altitude and the antenna gain is derived. Next,
using circle packing theory, the three-dimensional locations of the UAVs is
determined in a way that the total coverage area is maximized while maximizing
the coverage lifetime of the UAVs. Our results show that, in order to mitigate
interference, the altitude of the UAVs must be properly adjusted based on the
beamwidth of the directional antenna as well as coverage requirements.
Furthermore, the minimum number of UAVs needed to guarantee a target coverage
probability for a given geographical area is determined. Numerical results
evaluate the various tradeoffs involved in various UAV deployment scenarios.


title: Analysis of polarizability measurements made with atom interferometry

abstract:
  We present revised measurements of the static electric dipole
polarizabilities of K, Rb, and Cs based on atom interferometer experiments
presented in [Phys. Rev. A 2015, 92, 052513] but now re-analyzed with new
calibrations for the magnitude and geometry of the applied electric field
gradient. The resulting polarizability values did not change, but the
uncertainties were significantly reduced. Then we interpret several
measurements of alkali metal atomic polarizabilities in terms of atomic
oscillator strengths $f_{ik}$, Einstein coefficients $A_{ik}$, state lifetimes
$\tau_{k}$, transition dipole matrix elements $D_{ik}$, line strengths
$S_{ik}$, and van der Waals $C_6$ coefficients. Finally, we combine atom
interferometer measurements of polarizabilities with independent measurements
of lifetimes and $C_6$ values in order to quantify the residual contribution to
polarizability due to all atomic transitions other than the principal
$ns$-$np_J$ transitions for alkali metal atoms.


title: Heavy subsets and non-contractible trajectories

abstract:
  Entov and Polterovich defined heaviness for closed subsets of a symplectic
manifold by using the Hamiltonian Floer theory on contractible trajectories.
Heavy subsets are known to be non-displaceable. In the present paper, we define
a relative symplectic capacity $C(M,X,R;e)$ for a symplectic manifold
$(M,\omega)$ and its subset $X$ which measures the existence of
non-contractible trajectories of Hamiltonian isotopies on the product with
annulus. We prove that $C(M,X,R;e)$ is finite if $(M,\omega)$ is monotone and
$X$ is a heavy subset. We also prove that $C(M,X,R;e)$ is infinite if $X$ is a
displaceable compact subset.


title:
Content-based Cognitive Interference Control for City Monitoring
  Applications in the Urban IoT

abstract:
  In the Urban Internet of Things devices and systems are interconnected at the
city scale to provide innovative services to the citizens.However, the traffic
generated by the sensing and processing systems may overload local access
networks. A coexistence problem arises where concurrent applications mutually
interfere and compete for available resources. This effect is further
aggravated by the multiple scales involved and heterogeneity of the networks
supporting the urban IoT. One of the main contributions of this paper is the
introduction of the notion of content-oriented cognitive interference control
in heterogeneous local access networks supporting computing and data processing
in the urban IoT. A network scenario where multiple communication technologies,
such as Device-to-Device and Long Term Evolution (LTE), is considered. The
focus of the present paper is on city monitoring applications, where a video
data stream generated by a camera system is remotely processed to detect
objects. The cognitive network paradigm is extended to dynamically shape the
interference pattern generated by concurrent data streams and induce a packet
loss trajectory compatible with video processing algorithms. Numerical results
show that the proposed cognitive transmission strategy enables a significant
throughput increase of interfering applications for a target accuracy of the
monitoring application.


title: Distributed Graphical Simulation in the Cloud

abstract:
  Graphical simulations are a cornerstone of modern media and films. But
existing software packages are designed to run on HPC nodes, and perform poorly
in the computing cloud. These simulations have complex data access patterns
over complex data structures, and mutate data arbitrarily, and so are a poor
fit for existing cloud computing systems. We describe a software architecture
for running graphical simulations in the cloud that decouples control logic,
computations and data exchanges. This allows a central controller to balance
load by redistributing computations, and recover from failures. Evaluations
show that the architecture can run existing, state-of-the-art simulations in
the presence of stragglers and failures, thereby enabling this large class of
applications to use the computing cloud for the first time.


title: $\mathfrak G$-bases in free (locally convex) topological vector spaces

abstract:
  We characterize topological (and uniform) spaces whose free (locally convex)
topological vector spaces have a local $\mathfrak G$-base. A topological space
$X$ has a local $\mathfrak G$-base if every point $x$ of $X$ has a neighborhood
base $(U_\alpha)_{\alpha\in\omega^\omega}$ such that $U_\beta\subset U_\alpha$
for all $\alpha\le\beta$ in $\omega^\omega$. To construct $\mathfrak G$-bases
in free topological vector spaces, we exploit a new description of the topology
of a free topological vector space over a topological (or more generally,
uniform) space.