title:
The R136 star cluster dissected with Hubble Space Telescope/STIS. I.
  Far-ultraviolet spectroscopic census and the origin of HeII 1640 in young
  star clusters

abstract:
  We introduce a HST/STIS stellar census of R136a, the central ionizing star
cluster of 30 Doradus. We present low resolution far-ultraviolet STIS/MAMA
spectroscopy of R136 using 17 contiguous 52x0.2 arcsec slits which together
provide complete coverage of the central 0.85 parsec (3.4 arcsec). We provide
spectral types of 90% of the 57 sources brighter than m_F555W = 16.0 mag within
a radius of 0.5 parsec of R136a1, plus 8 additional nearby sources including
R136b (O4\,If/WN8). We measure wind velocities for 52 early-type stars from CIV
1548-51, including 16 O2-3 stars. For the first time we spectroscopically
classify all Weigelt & Baier members of R136a, which comprise three WN5 stars
(a1-a3), two O supergiants (a5-a6) and three early O dwarfs (a4, a7, a8). A
complete Hertzsprung-Russell diagram for the most massive O stars in R136 is
provided, from which we obtain a cluster age of 1.5+0.3_-0.7 Myr. In addition,
we discuss the integrated ultraviolet spectrum of R136, and highlight the
central role played by the most luminous stars in producing the prominent HeII
1640 emission line. This emission is totally dominated by very massive stars
with initial masses above ~100 Msun. The presence of strong HeII 1640 emission
in the integrated light of very young star clusters (e.g A1 in NGC 3125)
favours an initial mass function extending well beyond a conventional upper
limit of 100 Msun. We include montages of ultraviolet spectroscopy for LMC O
stars in the Appendix. Future studies in this series will focus on optical
STIS/CCD medium resolution observations.


title: The "ideal" tearing mode: theory and resistive MHD simulations

abstract:
  Classical MHD reconnection theories, both the stationary Sweet-Parker model
and the tearing instability, are known to provide rates which are too slow to
explain the observations. However, a recent analysis has shown that there
exists a critical threshold on current sheet's thickness, namely a/L~S^(-1/3),
beyond which the tearing modes evolve on fast macroscopic Alfvenic timescales,
provided the Lunquist number S is high enough, as invariably found in solar and
astrophysical plasmas. Therefore, the classical Sweet-Parker scenario, for
which the diffusive region scales as a/L~S^(-1/2) and thus can be up to ~100
times thinner than the critical value, is likely to be never realized in
nature, as the current sheet itself disrupts in the elongation process. We
present here two-dimensional, compressible, resistive MHD simulations, with S
ranging from 10^5 to 10^7, that fully confirm the linear analysis. Moreover, we
show that a secondary plasmoid instability always occurs when the same critical
scaling is reached on the local, smaller scale, leading to a cascading
explosive process, reminiscent of the flaring activity.


title:
Relaxed Connected Dominating Set Problem with Application to Secure
  Power Network Design

abstract:
  This paper investigates a combinatorial optimization problem motived from a
secure power network design application in [D\'{a}n and Sandberg 2010]. Two
equivalent graph optimization formulations are derived. One of the formulations
is a relaxed version of the connected dominating set problem, and hence the
considered problem is referred to as relaxed connected dominating set (RCDS)
problem. The RCDS problem is shown to be NP-hard, even for planar graphs. A
mixed integer linear programming formulation is presented. In addition, for
planar graphs a fixed parameter polynomial time solution methodology based on
sphere-cut decomposition and dynamic programming is presented. The computation
cost of the sphere-cut decomposition based approach grows linearly with problem
instance size, provided that the branchwidth of the underlying graph is fixed
and small. A case study with IEEE benchmark power networks verifies that small
branchwidth are not uncommon in practice. The case study also indicates that
the proposed methods show promise in computation efficiency.


title: Event shape analysis in ultrarelativistic nuclear collisions

abstract:
  We present a novel method for sorting events. So far, single variables like
flow vector magnitude were used for sorting events. Our approach takes into
account the whole azimuthal angle distribution rather than a single variable.
This method allows us to determine the good measure of the event shape,
providing a multiplicity-independent insight. We discuss the advantages and
disadvantages of this approach, the possible usage in femtoscopy, and other
more exclusive experimental studies.


title:
Understanding the residual patterns of timing solutions of radio pulsars
  with a model of magnetic field oscillation

abstract:
  We explain some phenomena existing generally in the timing residuals:
amplitude and sign of the second derivative of a pulsar's spin-frequency
($\ddot\nu$), some sophisticated residual patterns, which also change with the
time span of data segments. The sample is taken from Hobbs et al.\,(2010), in
which the pulsar's spin-frequency and its first derivative have been subtracted
from the timing solution fitting. We first classify the timing residual
patterns into different types based on the sign of $\ddot\nu$. Then we use the
magnetic field oscillation model developed in our group \citep{zhang12a} to fit
successfully the different kinds of timing residuals with the Markov Chain
Monte Carlo method. Finally, we simulate the spin evolution over 20 years for a
pulsar with typical parameters and analyze the data with the conventional
timing solution fitting. By choosing different segments of the simulated data,
we find that most of the observed residual patterns can be reproduced
successfully. This is the first time that the observed residual patterns are
fitted by a model and reproduced by simulations with very few parameters. From
the distribution of the different residual patterns in the $P-\dot P$ diagram,
we argue that (1) a single magnetic field oscillation mode exists commonly in
all pulsars throughout their lifetimes; (2) there may be a transition period
over the lifetimes of pulsars, in which multiple magnetic field oscillation
modes exist.


title:
Tuning the spin Hall effect of Pt from the moderately dirty to the
  superclean regime

abstract:
  We systematically measure and analyze the spin diffusion length and the spin
Hall effect in Pt with a wide range of conductivities using the spin absorption
method in lateral spin valve devices. We observe a linear relation between the
spin diffusion length and the conductivity, evidencing that the spin relaxation
in Pt is governed by the Elliott-Yafet mechanism. We find a single intrinsic
spin Hall conductivity ($\sigma_{SH}^{int}=1600\pm150\: \Omega^{-1}cm^{-1}$)
for Pt in the full range studied which is in good agreement with theory. For
the first time we have obtained the crossover between the moderately dirty and
the superclean scaling regimes of the spin Hall effect by tuning the
conductivity. This is equivalent to that obtained for the anomalous Hall
effect. Our results explain the spread of the spin Hall angle values in the
literature and find a route to maximize this important parameter.


title:
Is the magnetic field making the inner crust of neutron stars more
  heterogeneous?

abstract:
  We study the effect of strong magnetic fields, of the order of
$10^{15}-10^{17}$ G, on the extension of the crust of magnetized neutron stars.
The dynamical instability region of neutron-proton-electron ($npe$) matter at
subsaturation densities and the mode with the largest growth rate are
determined within a relativistic mean field model. It is shown that a strong
magnetic field has a large effect on the instability region, defining the
crust-core transition as a wide density range.


title: Pseudopotential for the 2D contact interaction

abstract:
  We propose a smooth pseudopotential for the contact interaction acting
between ultracold atoms confined to two dimensions. The pseudopotential
reproduces the scattering properties of the repulsive contact interaction up to
200 times more accurately than a hard disk potential, and in the attractive
branch gives a 10-fold improvement in accuracy over the square well potential.
Furthermore, the new potential enables diffusion Monte Carlo simulations of the
ultracold gas to be run 15 times quicker than was previously possible.


title: Chiral condensate in the Schwinger model with Matrix Product Operators

abstract:
  Tensor network (TN) methods, in particular the Matrix Product States (MPS)
ansatz, have proven to be a useful tool in analyzing the properties of lattice
gauge theories. They allow for a very good precision, much better than standard
Monte Carlo (MC) techniques for the models that have been studied so far, due
to the possibility of reaching much smaller lattice spacings. The real reason
for the interest in the TN approach, however, is its ability, shown so far in
several condensed matter models, to deal with theories which exhibit the
notorious sign problem in MC simulations. This makes it prospective for dealing
with the non-zero chemical potential in QCD and other lattice gauge theories,
as well as with real-time simulations. In this paper, using matrix product
operators, we extend our analysis of the Schwinger model at zero temperature to
show the feasibility of this approach also at finite temperature. This is an
important step on the way to deal with the sign problem of QCD. We analyze in
detail the chiral symmetry breaking in the massless and massive cases and show
that the method works very well and gives good control over a broad range of
temperatures, essentially from zero to infinite temperature.


title: Persistence of unvisited sites in quantum walks on a line

abstract:
  We analyze the asymptotic scaling of persistence of unvisited sites for
quantum walks on a line. In contrast to the classical random walk there is no
connection between the behaviour of persistence and the scaling of variance. In
particular, we find that for a two-state quantum walks persistence follows an
inverse power-law where the exponent is determined solely by the coin
parameter. Moreover, for a one-parameter family of three-state quantum walks
containing the Grover walk the scaling of persistence is given by two
contributions. The first is the inverse power-law. The second contribution to
the asymptotic behaviour of persistence is an exponential decay coming from the
trapping nature of the studied family of quantum walks. In contrast to the
two-state walks both the exponent of the inverse power-law and the decay
constant of the exponential decay depend also on the initial coin state and its
coherence. Hence, one can achieve various regimes of persistence by altering
the initial condition, ranging from purely exponential decay to purely inverse
power-law behaviour.


title: Robust permanence for ecological maps

abstract:
  We consider ecological difference equations of the form $X_{t+1}^i =X_t^i
A_i(X_t)$ where $X_t^i$ is a vector of densities corresponding to the
subpopulations of species $i$ (e.g. subpopulations of different ages or living
in different patches), $X_t=(X_t^1,X_t^2,\dots,X_t^m)$ is state of the entire
community, and $A_i(X_t)$ are matrices determining the update rule for species
$i$. These equations are permanent if they are dissipative and the extinction
set $\{X: \prod_i \|X^i\|=0\}$ is repelling. If permanence persists under
perturbations of the matrices $A_i(X)$, the equations are robustly permanent.
We provide sufficient and necessary conditions for robust permanence in terms
of Lyapunov exponents for invariant measures supported by the extinction set.
Applications to ecological and epidemiological models are given.


title:
Engineering autonomous error correction in stabilizer codes at finite
  temperature

abstract:
  We present an error correcting protocol that enhances the lifetime of
stabilizer code based qubits which are susceptible to the creation of pairs of
localized defects (due to string-like error operators) at finite temperature,
such as the toric code. The primary tool employed is dynamic application of a
local, unitary operator which exchanges defects and thereby translates
localized excitations. Crucially, the protocol does not require any
measurements of stabilizer operators, and therefore can be used to enhance the
lifetime of a qubit in the absence of such experimental resources.


title:
Isotopic ratios of H, C, N, O, and S in comets C/2012 F6 (Lemmon) and
  C/2014 Q2 (Lovejoy)

abstract:
  The apparition of bright comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy) in
March-April 2013 and January 2015, combined with the improved observational
capabilities of submillimeter facilities, offered an opportunity to carry out
sensitive compositional and isotopic studies of the volatiles in their coma. We
observed comet Lovejoy with the IRAM 30m telescope between 13 and 26 January
2015, and with the Odin submillimeter space observatory on 29 January - 3
February 2015. We detected 22 molecules and several isotopologues. The
H$_2^{16}$O and H$_2^{18}$O production rates measured with Odin follow a
periodic pattern with a period of 0.94 days and an amplitude of ~25%. The
inferred isotope ratios in comet Lovejoy are $^{16}$O/$^{18}$O = 499 $\pm$ 24
and D/H = 1.4 $\pm$ 0.4 $\times 10^{-4}$ in water, $^{32}$S/$^{34}$S = 24.7
$\pm$ 3.5 in CS, all compatible with terrestrial values. The ratio
$^{12}$C/$^{13}$C = 109 $\pm$ 14 in HCN is marginally higher than terrestrial
and $^{14}$N/$^{15}$N = 145 $\pm$ 12 in HCN is half the Earth ratio. Several
upper limits for D/H or 12C/13C in other molecules are reported. From our
observation of HDO in comet C/2014 Q2 (Lovejoy), we report the first D/H ratio
in an Oort Cloud comet that is not larger than the terrestrial value. On the
other hand, the observation of the same HDO line in the other Oort-cloud comet,
C/2012 F6 (Lemmon), suggests a D/H value four times higher. Given the previous
measurements of D/H in cometary water, this illustrates that a diversity in the
D/H ratio and in the chemical composition, is present even within the same
dynamical group of comets, suggesting that current dynamical groups contain
comets formed at very different places or times in the early solar system.


title: Deterministic generations of NOON states via shortcuts to adiabaticity

abstract:
  NOON states play the important roles in quantum information processings and
quantum metrology, but the fidelities of these states generated previously are
limited typically by the practically-unavoidable decoherence and operational
imperfections. Here, we propose an efficient scheme to generate photonic NOON
states alternatively by rapid population passage technique via shortcut to
adiabaticity (STA), rather than the usual Rabi oscillations. Since the
deterministic population passages based on the STAs are insensitive to details
of the operations and can be implemented as fast as the Rabi oscillations, the
fidelity of the generated NOON state could be satisfactorily high. The
feasibility of the proposal is demonstrated specifically with the experimental
circuit QED systems by rapidly driving two artifical qutrits.


title: Observation of magnetic fragmentation in spin ice

abstract:
  Fractionalised excitations that emerge from a many body system have revealed
rich physics and concepts, from composite fermions in two-dimensional electron
systems, revealed through the fractional quantum Hall effect, to spinons in
antiferromagnetic chains and, more recently, fractionalisation of Dirac
electrons in graphene and magnetic monopoles in spin ice. Even more surprising
is the fragmentation of the degrees of freedom themselves, leading to
coexisting and a priori independent ground states. This puzzling phenomenon was
recently put forward in the context of spin ice, in which the magnetic moment
field can fragment, resulting in a dual ground state consisting of a
fluctuating spin liquid, a so-called Coulomb phase, on top of a magnetic
monopole crystal. Here we show, by means of neutron scattering measurements,
that such fragmentation occurs in the spin ice candidate Nd$_2$Zr$_2$O$_7$. We
observe the spectacular coexistence of an antiferromagnetic order induced by
the monopole crystallisation and a fluctuating state with ferromagnetic
correlations. Experimentally, this fragmentation manifests itself via the
superposition of magnetic Bragg peaks, characteristic of the ordered phase, and
a pinch point pattern, characteristic of the Coulomb phase. These results
highlight the relevance of the fragmentation concept to describe the physics of
systems that are simultaneously ordered and fluctuating.


title:
Reduced quantum dynamics with initial system-environment correlations
  characterized by pure Markov states

abstract:
  Any tripartite state which saturates the strong subadditivity relation for
the quantum entropy is defined as the Markov state.A tripartite pure state
describing an open system, its environment and their purifying system isa pure
Markov state iff the bipartite marginal state of purifying system and
environment is a product state. It has been shown that as long as the
purification of the input system-environment state is a pure Markov state the
reduced dynamics of the open system can be described, on the support of initial
system state, by a quantum channel for every joint unitary evolution of the
system-environment composite even in the presence of initial correlations.
Entanglement, discord and classical correlations of the initial
system-environment states implied by the pure Markov state are analyzed and it
has been shown that all these correlations are entirely specified by the
entropy of the environment. Some implications concerning perfect quantum error
correction procedure and quantum Markovian dynamics are presented.


title:
Structure-preserving low multilinear rank approximation of antisymmetric
  tensors

abstract:
  This paper is concerned with low multilinear rank approximations to
antisymmetric tensors, that is, multivariate arrays for which the entries
change sign when permuting pairs of indices. We show which ranks can be
attained by an antisymmetric tensor and discuss the adaption of existing
approximation algorithms to preserve antisymmetry, most notably a Jacobi
algorithm. Particular attention is paid to the important special case when
choosing the rank equal to the order of the tensor. It is shown that this case
can be addressed with an unstructured rank-$1$ approximation. This allows for
the straightforward application of the higher-order power method, for which we
discuss effective initialization strategies.


title: Time-Harmonic Optical Chirality in Inhomogeneous Space

abstract:
  Optical chirality has been recently suggested to complement the physically
relevant conserved quantities of the well-known Maxwell's equations. This
time-even pseudoscalar is expected to provide further insight in polarization
phenomena of electrodynamics such as spectroscopy of chiral molecules.
Previously, the corresponding continuity equation was stated for homogeneous
lossless media only. We extend the underlying theory to arbitrary setups and
analyse piecewise-constant material distributions in particular. Our
implementation in a Finite Element Method framework is applied to illustrative
examples in order to introduce this novel tool for the analysis of
time-harmonic simulations of nano-optical devices.


title: Selective model-predictive control for flocking systems

abstract:
  In this paper the optimal control of alignment models composed by a large
number of agents is investigated in presence of a selective action of a
controller, acting in order to enhance consensus. Two types of selective
controls have been presented: an homogeneous control filtered by a selective
function and a distributed control active only on a selective set. As a first
step toward a reduction of computational cost, we introduce a model predictive
control (MPC) approximation by deriving a numerical scheme with a feedback
selective constrained dynamics. Next, in order to cope with the numerical
solution of a large number of interacting agents, we derive the mean-field
limit of the feedback selective constrained dynamics, which eventually will be
solved numerically by means of a stochastic algorithm, able to simulate
efficiently the selective constrained dynamics. Finally, several numerical
simulations are reported to show the efficiency of the proposed techniques.


title:
Weak equivalence of stationary actions and the entropy realization
  problem

abstract:
  We introduce the notion of weak containment for stationary actions of a
countable group and define a natural topology on the space of weak equivalence
classes. We prove that Furstenberg entropy is an invariant of weak equivalence,
and moreover that it descends to a continuous function on the space of weak
equivalence classes.


title:
Cluster algebras and category O for representations of Borel subalgebras
  of quantum affine algebras

abstract:
  Let $\mathcal{O}$ be the category of representations of the Borel subalgebra
of a quantum affine algebra introduced by Jimbo and the first author. We show
that the Grothendieck ring of a certain monoidal subcategory of $\mathcal{O}$
has the structure of a cluster algebra of infinite rank, with an initial seed
consisting of prefundamental representations. In particular, the celebrated
Baxter relations for the 6-vertex model get interpreted as Fomin-Zelevinsky
mutation relations.

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


title: Non-linear Dimensionality Regularizer for Solving Inverse Problems

abstract:
  Consider an ill-posed inverse problem of estimating causal factors from
observations, one of which is known to lie near some (un- known)
low-dimensional, non-linear manifold expressed by a predefined Mercer-kernel.
Solving this problem requires simultaneous estimation of these factors and
learning the low-dimensional representation for them. In this work, we
introduce a novel non-linear dimensionality regulariza- tion technique for
solving such problems without pre-training. We re-formulate Kernel-PCA as an
energy minimization problem in which low dimensionality constraints are
introduced as regularization terms in the energy. To the best of our knowledge,
ours is the first at- tempt to create a dimensionality regularizer in the KPCA
framework. Our approach relies on robustly penalizing the rank of the recovered
fac- tors directly in the implicit feature space to create their
low-dimensional approximations in closed form. Our approach performs robust
KPCA in the presence of missing data and noise. We demonstrate state-of-the-art
results on predicting missing entries in the standard oil flow dataset.
Additionally, we evaluate our method on the challenging problem of Non-Rigid
Structure from Motion and our approach delivers promising results on CMU mocap
dataset despite the presence of significant occlusions and noise.


title: L-space fillings and generalized solid tori

abstract:
  Much work has been done recently towards trying to understand the topological
significance of being an L-space. Building on work of Rasmussen and Rasmussen,
we give a topological characterisation of Floer simple manifolds such that all
non-longitudinal fillings are L-spaces. We use this to partially classify
L-space twisted torus knots in $S^1 \times S^2$ and resolve a question asked by
Rasmussen and Rasmussen.


title:
The melting of stable glasses is governed by nucleation-and-growth
  dynamics

abstract:
  We discuss the microscopic mechanisms by which low-temperature amorphous
states, such as ultrastable glasses, transform into equilibrium fluids, after a
sudden temperature increase. Experiments suggest that this process is similar
to the melting of crystals, thus differing from the behaviour found in ordinary
glasses. We rationalize these observations using the physical idea that the
transformation process takes place very close to a `hidden' equilibrium
first-order phase transition, which is observed in systems of coupled replicas.
We illustrate our views using simulation results for a simple two-dimensional
plaquette spin model, which is known to exhibit a range of glassy behaviour.
Our results suggest that nucleation-and-growth dynamics, as found near ordinary
first-order transitions, is also the correct theoretical framework to analyse
the melting of ultrastable glasses. Our approach provides a unified
understanding of multiple experimental observations, such as propagating
melting fronts, large kinetic stability ratios, and `giant' dynamic
lengthscales.


title: Chromatic index, treewidth and maximum degree

abstract:
  We conjecture that any graph $G$ with treewidth~$k$ and maximum degree
$\Delta(G)\geq k + \sqrt{k}$ satisfies $\chi'(G)=\Delta(G)$. In support of the
conjecture we prove its fractional version. We also show that any graph $G$
with treewidth~$k\geq 4$ and maximum degree $2k-1$ satisfies
$\chi'(G)=\Delta(G)$, improving an old result of Vizing.


title:
Separable metamaterials: analytical ab-initio homogenization and
  chirality

abstract:
  We investigate the ab-initio homogenization of separable metamaterials with
factorized dielectric permittivity profile which can be achieved through
suitable grey-scale permittivity design techniques. Separability allows such
metamaterials to be physically regarded as the superposition of three
fictitious 1D generating media. We prove that, in the long-wavelength limit,
separable metamaterials admit simple and analytical description of their
electromagnetic bi-anisotropic response which can be reconstructed from the
properties of the 1D generating media. Our approach provides a strategy which
allows the full ab-initio and flexible design of a complex bianisotropic
response by using 1D metamaterials as basic building blocks.


title:
Substitutability of Spectrum and Cloud-based Antennas in Virtualised
  Wireless Networks

abstract:
  Some of the new trends emerging in future wireless networks enable a vastly
increased fluidity in accessing a wide range of resources, thus supporting
flexible network composition and dynamic allocation of resources to virtual
network operators (VNOs). In this work we study a new resource allocation
opportunity that is enabled by the cloud radio access network architecture. In
particular, we investigate the relationship between the cloud-based antennas
and spectrum as two important resources in virtualized wireless networks. We
analyze the interplay between spectrum and antennas in the context of an
auction-based allocation mechanism through which VNOs can bid for a combination
of the two types of resources. Our analysis shows that the complementarity and
partial substitutability of the two resources significantly impact the results
of the allocation of those resources and uncovers the possibility of divergent
interests between the spectrum and the infrastructure providers.


title: Assembly and Phase Transitions within Colloidal Crystals

abstract:
  Micrometre sized colloidal particles can be viewed as large atoms with
tailorable size, shape and interactions. These building blocks can assemble
into extremely rich structures and phases, in which the thermal motions of
particles can be directly imaged and tracked using optical microscopy. Hence,
colloidal particles are excellent model systems for studying phase transitions,
especially for poorly understood kinetic and nonequilibrium microscale
processes. Advances in colloid fabrication, assembly and computer simulations
have opened up numerous possibilities for such research. In this Review, we
describe recent progress in the study of colloidal crystals composed of tunable
isotropic spheres, anisotropic particles and active particles. We focus on
advances in crystallization, melting and solid solid transitions, and highlight
challenges and future perspectives in phase transition studies within colloidal
crystals.


title:
Reliability of the time splitting Fourier method for singular solutions
  in quantum fluids

abstract:
  We extensively study the numerical accuracy of the well-known time splitting
Fourier spectral method for the approximation of singular solutions of the
Gross-Pitaevskii equation. In particular, we explore its capability of
preserving a steady-state vortex solution, whose density profile is
approximated by a very accurate diagonal Pad\'e expansion of order 8, here
explicitly derived for the first time. Although the Fourier spectral method
turns out to be only slightly more accurate than a time splitting finite
difference scheme, the former is reliable and efficient. Moreover, at a
post-processing stage, it allows an accurate evaluation of the solution outside
grid points, thus becoming particularly appealing when high resolution is
needed, such as in the study of quantum vortex interactions.


title:
Approximate scale invariance in particle systems: a large-dimensional
  justification

abstract:
  Systems of particles interacting via inverse-power law potentials have an
invariance with respect to changes in length and temperature, implying a
correspondence in the dynamics and thermodynamics between different
`isomorphic' sets of temperatures and densities. In a recent series of works,
it has been argued that such correspondences hold to a surprisingly good
approximation in a much more general class of potentials, an observation that
summarizes many properties that have been observed in the past. In this paper
we show that such relations are exact in high-dimensional liquids and glasses,
a limit in which the conditions for these mappings to hold become transparent.
The special role played by the exponential potential is also confirmed.


title: The power of a critical heat engine

abstract:
  Since its inception about two centuries ago thermodynamics has sparkled
continuous interest and fundamental questions. According to the second law no
heat engine can have an efficiency larger than Carnot's efficiency. The latter
can be achieved by the Carnot engine, which however ideally operates in
infinite time, hence delivers null power. A currently open question is whether
the Carnot efficiency can be achieved at finite power. Most of the previous
works addressed this question within the Onsager matrix formalism of linear
response theory. Here we pursue a different route based on finite-size-scaling
theory. We focus on quantum Otto engines and show that when the working
substance is at the verge of a second order phase transition diverging energy
fluctuations can enable approaching the Carnot point without sacrificing power.
The rate of such approach is dictated by the critical indices, thus showing the
universal character of our analysis.


title:
Ultra-stable optical frequency dissemination on a multi-access fibre
  network

abstract:
  We report the dissemination of an ultrastable optical frequency signal to two
distant users simultaneously using a branching network. The ultrastable signal
is extracted along a main fibre link; it is optically tracked with a
narrow-linewidth laser diode, which light is injected in a secondary link. The
propagation noise of both links is actively compensated. We implement this
scheme with two links of 50-km fibre spools, the extraction being setup at the
mid-point of the main link. We show that the extracted signal at the end of the
secondary link exhibits fractional frequency instability of 1.4x10-15 at 1-s
measurement time, almost equal to the 1.3x10-15 instability of the main link
output end. The long-term instabilities are also very similar, at a level of
3-5x10-20 at 3x104-s integration time. We also show that the setting up of this
extraction device, or a simpler one, at the main link input, can test the
proper functioning of the noise rejection on this main link. This work is a
significant step towards a robust and flexible ultra-stable network for
multi-users dissemination.


title:
A Commentary on Teichm\"uller's paper "\"Uber Extremalprobleme der
  konformen Geometrie" (On extremal problems in conformal geometry)

abstract:
  We comment on the paper \"Uber Extremalprobleme der konformen Geometrie (On
extremal problems in conformal geometry) by Teichm\"uller, published in 1941.
This paper contains ideas on a wide generalization of his previous work on the
solution of extremal problems in conformal geometry. The generalization
concerns at the same time the fields of function theory, topology and algebra.
The final version of this paper will appear as a chapter in Volume VI of the
Handbook of Teichm\"uller theory. This volume is dedicated to the memory of
Alexander Grothendieck.


title: Identity Mappings in Deep Residual Networks

abstract:
  Deep residual networks have emerged as a family of extremely deep
architectures showing compelling accuracy and nice convergence behaviors. In
this paper, we analyze the propagation formulations behind the residual
building blocks, which suggest that the forward and backward signals can be
directly propagated from one block to any other block, when using identity
mappings as the skip connections and after-addition activation. A series of
ablation experiments support the importance of these identity mappings. This
motivates us to propose a new residual unit, which makes training easier and
improves generalization. We report improved results using a 1001-layer ResNet
on CIFAR-10 (4.62% error) and CIFAR-100, and a 200-layer ResNet on ImageNet.
Code is available at: https://github.com/KaimingHe/resnet-1k-layers


title:
MasterPVA and WAlg: Mathematica packages for Poisson vertex algebras and
  classical affine $\mathcal{W}$-algebras

abstract:
  We give an introduction to the Mathematica packages "MasterPVA" and
"MasterPVAmulti used to compute lambda-brackets in Poisson vertex algebras,
which play an important role in the theory of infinite-dimensional Hamiltonian
systems. As an application, we give an introduction to the Mathematica package
"WAlg" aimed to compute the lambda-brackets among the generators of classical
affine W-algebras. The use of these packages is shown by providing some
explicit examples.


title: Dissipation, Correlation and Lags in Heat Engines

abstract:
  By modelling heat engines as driven multi-partite system we show that their
dissipation can be expressed in terms of the lag (relative entropy) between the
perturbed state of each partition and their equilibrium state, and the
correlations that build up among the partitions. We illustrate the rich
interplay between correlations and lags with a two-qubit device driven by a
quantum gate.


title: Bianchi identities for the Riemann and Weyl tensors

abstract:
  The purpose of this paper is to revisit the Bianchi identities existing for
the Riemann and Weyl tensors in the combined framework of the formal theory of
systems of partial differential equations (Spencer cohomology, differential
systems, formal integrability) and Algebraic Analysis (homological algebra,
differential modules, duality). In particular, we prove that the n 2 (n 2 --
1)(n -- 2)/24 generating Bianchi identities for the Riemann tensor are first
order and can be easily described by means of the Spencer cohomology of the
first order Killing symbol in arbitrary dimension n $\ge$ 2. Similarly, the n(n
2 -- 1)(n + 2)(n -- 4)/24 generating Bianchi identities for the Weyl tensor are
first order and can be easily described by means of the Spencer cohomology of
the first order conformal Killing symbol in arbitrary dimension n $\ge$ 5. As A
MOST SURPRISING RESULT, the 9 generating Bianchi identities for the Weyl tensor
are of second order in dimension n = 4 while the analogue of the Weyl tensor
has 5 components of third order in the metric with 3 first order generating
Bianchi identities in dimension n = 3. The above results, which could not be
obtained otherwise, are valid for any non-degenerate metric of constant
riemannian curvature and do not depend on any conformal factor. They are
checked in an Appendix produced by Alban Quadrat (INRIA, Lille) by means of
computer algebra. We finally explain why the work of Lanczos and followers is
not coherent with these results and must therefore be also revisited.


title:
Estimating orthant probabilities of high dimensional Gaussian vectors
  with an application to set estimation

abstract:
  The computation of Gaussian orthant probabilities has been extensively
studied for low-dimensional vectors. Here, we focus on the high-dimensional
case and we present a two-step procedure relying on both deterministic and
stochastic techniques. The proposed estimator relies indeed on splitting the
probability into a low-dimensional term and a remainder. While the
low-dimensional probability can be estimated by fast and accurate quadrature,
the remainder requires Monte Carlo sampling. We further refine the estimation
by using a novel asymmetric nested Monte Carlo (anMC) algorithm for the
remainder and we highlight cases where this approximation brings substantial
efficiency gains. The proposed methods are compared against state-of-the-art
techniques in a numerical study, which also calls attention to the advantages
and drawbacks of the procedure. Finally, the proposed method is applied to
derive conservative estimates of excursion sets of expensive to evaluate
deterministic functions under a Gaussian random field prior, without requiring
a Markov assumption. Supplementary material for this article is available
online.


title: Concentration results for directed polymer with unbounded jumps

abstract:
  We study the free energy and its relevant quantity for the directed polymer
in random environment. The polymer is allowed to make unbounded jumps and the
environment is given by the Bernoulli variables. We first establish the
concentration of the ground state energy of polymer at zero temperature.
Secondly, we also prove the same property of the free energy at finite
temperature. In the proof, we use the fact that the maximum jump of any polymer
nearly minimizing energy is not too large with high probability. This is an
interesting property itself from the first passage percolation viewpoint.


title: Fractional Sobolev Spaces and Functions of Bounded Variation

abstract:
  We investigate the 1D Riemann-Liouville fractional derivative focusing on the
connections with fractional Sobolev spaces, the space $BV$ of functions of
bounded variation, whose derivatives are not functions but measures and the
space $SBV$, say the space of bounded variation functions whose derivative has
no Cantor part. We prove that $SBV$ is included in $W^{s,1} $ for every $s \in
(0,1)$ while the result remains open for $BV$. We study examples and address
open questions.


title:
Reduced Memory Footprint in Multiparametric Quadratic Programming by
  Exploiting Low Rank Structure

abstract:
  In multiparametric programming an optimization problem which is dependent on
a parameter vector is solved parametrically. In control, multiparametric
quadratic programming (mp-QP) problems have become increasingly important since
the optimization problem arising in Model Predictive Control (MPC) can be cast
as an mp-QP problem, which is referred to as explicit MPC. One of the main
limitations with mp-QP and explicit MPC is the amount of memory required to
store the parametric solution and the critical regions. In this paper, a method
for exploiting low rank structure in the parametric solution of an mp-QP
problem in order to reduce the required memory is introduced. The method is
based on ideas similar to what is done to exploit low rank modifications in
generic QP solvers, but is here applied to mp-QP problems to save memory. The
proposed method has been evaluated experimentally, and for some examples of
relevant problems the relative memory reduction is an order of magnitude
compared to storing the full parametric solution and critical regions.


title:
Birational models of moduli spaces of coherent sheaves on the projective
  plane

abstract:
  We study the birational geometry of moduli spaces of semistable sheaves on
the projective plane via Bridgeland stability conditions. We show that the
entire MMP of their moduli spaces can be run via wall-crossing. Via a
description of the walls, we give a numerical description of their movable
cones, along with its chamber decomposition corresponding to minimal models. As
an application, we show that for primitive vectors, all birational models
corresponding to open chambers in the movable cone are smooth and irreducible.


title: Photonic Quantum Information Processing

abstract:
  Information processing with light is ubiquitous, from communication,
metrology and imaging to computing. When we consider light as a quantum
mechanical object, new ways of information processing become possible. In this
review I give an overview how quantum information processing can be implemented
with single photons, and what hurdles still need to be overcome to implement
the various applications in practice. I will place special emphasis on the
quantum mechanical properties of light that make it different from classical
light, and how these properties relate to quantum information processing tasks.


title:
The involutive nature of the Littlewood-Richardson commutativity
  bijection

abstract:
  Littlewood-Richardson (LR) coefficients $c_{\mu\nu}^\lambda$ may be evaluated
by means of several combinatorial models, including the original LR tableaux of
skew shape $\lambda/\mu$ and weight $\nu$ and the LR hives with boundary edge
labels $\lambda$, $\mu$ and $\nu$. Unfortunately, neither of these reveal in
any obvious way the well-known symmetry property
$c_{\mu\nu}^\lambda=c_{\nu\mu}^\lambda$. Here we introduce two maps,
$\rho^{(n)}$ on LR tableaux and $\sigma^{(n)}$ on LR hives, that each
interchange contributions to $c_{\mu\nu}^\lambda$ and $c_{\nu\mu}^\lambda$ for
any partitions $\lambda$, $\mu$, $\nu$ of lengths no greater than $n$, and then
prove not only that each of them is a bijection, thereby making manifest the
required symmetry property, but also that both maps are involutions. The map
$\rho^{(n)}$ involves the iterative action of deletion operators on a given LR
tableau of skew shape $\lambda/\mu$ and weight $\nu$, that produce a sequence
of successively smaller tableaux whose consecutive inner shapes define a
certain Gelfand-Tsetlin pattern and determine a partner LR tableau of skew
shape $\lambda/\nu$ and weight $\mu$. Similarly, the map $\sigma^{(n)}$
involves repeated path removals from a given LR hive with boundary edge labels
$(\lambda,\mu,\nu)$ that give rise to a sequence of hives whose left-hand
boundary edge labels define the same Gelfand-Tsetlin pattern as before, which
is sufficient to determine a partner LR hive with boundary edge labels
$(\lambda,\nu,\mu)$. The deletions in tableaux are organised so as to preserve
the semistandard and lattice permutation properties of LR tableaux, while the
path removals in hives are designed to preserve both the triangle condition on
edge labels and the hive rhombus gradient positivity conditions. At all stages
illustrative examples are provided.


title:
CoinCalc -- A new R package for quantifying simultaneities of event
  series

abstract:
  We present the new R package CoinCalc for performing event coincidence
analysis (ECA), a novel statistical method to quantify the simultaneity of
events contained in two series of observations, either as simultaneous or
lagged coincidences within a user-specific temporal tolerance window. The
package also provides different analytical as well as surrogate-based
significance tests (valid under different assumptions about the nature of the
observed event series) as well as an intuitive visualization of the identified
coincidences. We demonstrate the usage of CoinCalc based on two typical
geoscientific example problems addressing the relationship between
meteorological extremes and plant phenology as well as that between soil
properties and land cover.


title:
An eigenvalue problem involving a degenerate and singular elliptic
  operator

abstract:
  We study an eigenvalue problem involving a degenerate and singular elliptic
operator on the whole space $\mathbb{R}^N$. We prove the existence of an
unbounded and increasing sequence of eigenvalues. Our study generalizes to the
case of degenerate and singular operators a result of A. Szulkin and M. Willem.


title:
Cosmology constraints from shear peak statistics in Dark Energy Survey
  Science Verification data

abstract:
  Shear peak statistics has gained a lot of attention recently as a practical
alternative to the two point statistics for constraining cosmological
parameters. We perform a shear peak statistics analysis of the Dark Energy
Survey (DES) Science Verification (SV) data, using weak gravitational lensing
measurements from a 139 deg$^2$ field. We measure the abundance of peaks
identified in aperture mass maps, as a function of their signal-to-noise ratio,
in the signal-to-noise range $0<\mathcal S / \mathcal N<4$. To predict the peak
counts as a function of cosmological parameters we use a suite of $N$-body
simulations spanning 158 models with varying $\Omega_{\rm m}$ and $\sigma_8$,
fixing $w = -1$, $\Omega_{\rm b} = 0.04$, $h = 0.7$ and $n_s=1$, to which we
have applied the DES SV mask and redshift distribution. In our fiducial
analysis we measure $\sigma_{8}(\Omega_{\rm m}/0.3)^{0.6}=0.77 \pm 0.07$, after
marginalising over the shear multiplicative bias and the error on the mean
redshift of the galaxy sample. We introduce models of intrinsic alignments,
blending, and source contamination by cluster members. These models indicate
that peaks with $\mathcal S / \mathcal N>4$ would require significant
corrections, which is why we do not include them in our analysis. We compare
our results to the cosmological constraints from the two point analysis on the
SV field and find them to be in good agreement in both the central value and
its uncertainty. We discuss prospects for future peak statistics analysis with
upcoming DES data.


title: From Krall discrete orthogonal polynomials to Krall polynomials

abstract:
  We show how to get Krall polynomials from Krall discrete polynomials using a
procedure of passing to the limit in some of the parameters of the family. We
also show that this procedure has to be different to the standard one used in
the Askey scheme to go from the classical discrete polynomials to the classical
polynomials.


title:
Multiple solutions for a nonlinear and non-homogeneous problem in
  Orlicz-Sobolev spaces

abstract:
  We study a non-homogeneous boundary value problem in a smooth bounded domain
in $\mathbb{R}^N$. We prove the existence of at least two nonnegative and
non-trivial weak solutions. Our approach relies on Orlicz-Sobolev spaces theory
combined with adequate variational methods and a variant of Mountain Pass
Lemma.


title: On a Kaehlerian space-time manifold

abstract:
  In this paper, the theory of space-time in 4-dimensional Kaehler manifold has
been studied. We have discussed the Einstein equation with cosmological
constant in perfect fluid Kaehler space-time manifold and proved that the
isotropic pressure, energy density and the energy momentum tensor vanish and
such a space-time manifold is an Einstein manifold. We have shown also that a
conformally flat perfect fluid Kaehler space-time manifold is infinitesimally
spatially isotropic relative to the velocity vector field. In last two
sections, we have studied weakly symmetric and weakly Ricci symmetric perfect
fluid Kaehler space-time manifolds and it has been shown, either the manifold
is of zero scalar curvature or the associated vector fields rho and alpha are
related by g(rho,alpha) = 4. At last, we have proved that the weakly Ricci
symmetric perfect fluid Kaehler space-time manifold of non-zero scalar
curvature does not exist.


title:
Inequalities for finite trigonometric sums. An interplay: with some
  series related to Harmonic numbers

abstract:
  An interplay between the sum of certain series related to Harmonic numbers
and certain finite trigonometric sums is investigated. This allows us to
express the sum of these series in terms of the considered trigonometric sums,
and permits us to find sharp inequalities bounding these trigonometric sums. In
particular, this answers positively an open problem of H. Chen (2010).


title: Exact Partition Functions for Gauge Theories on $\mathbb{R}^3_\lambda$

abstract:
  The noncommutative space $\mathbb{R}^3_\lambda$, a deformation of
$\mathbb{R}^3$, supports a $3$-parameter family of gauge theory models with
gauge-invariant harmonic term, stable vacuum and which are perturbatively
finite to all orders. Properties of this family are discussed. The partition
function factorizes as an infinite product of reduced partition functions, each
one corresponding to the reduced gauge theory on one of the fuzzy spheres
entering the decomposition of $\mathbb{R}^3_\lambda$. For a particular
sub-family of gauge theories, each reduced partition function is exactly
expressible as a ratio of determinants. A relation with integrable 2-D Toda
lattice hierarchy is indicated.


title: On a PDE involving the ${\cal A}_{p(\cdot)}$-Laplace operator

abstract:
  This paper establishes existence of solutions for a partial differential
equation in which a differential operator involving variable exponent growth
conditions is present. This operator represents a generalization of the
$p(\cdot)$-Laplace operator, i.e. $\Delta_{p(\cdot)}u={\rm div}(|\nabla
u|^{p(\cdot)-2}\nabla u)$, where $p(\cdot)$ is a continuous function. The proof
of the main result is based on Schauder's fixed point theorem combined with
adequate variational arguments. The function space setting used here makes
appeal to the variable exponent Lebesgue and Sobolev spaces.


title:
Benchmarking Concurrent Priority Queues: Performance of k-LSM and
  Related Data Structures

abstract:
  A number of concurrent, relaxed priority queues have recently been proposed
and implemented. Results are commonly reported for a throughput benchmark that
uses a uniform distribution of keys drawn from a large integer range, and
mostly for single systems. We have conducted more extensive benchmarking of
three recent, relaxed priority queues on four different types of systems with
different key ranges and distributions. While we can show superior throughput
and scalability for our own k-LSM priority queue for the uniform key
distribution, the picture changes drastically for other distributions, both
with respect to achieved throughput and relative merit of the priority queues.
The throughput benchmark alone is thus not sufficient to characterize the
performance of concurrent priority queues. Our benchmark code and k-LSM
priority queue are publicly available to foster future comparison.


title: Velocity-dependent quantum phase slips in 1D atomic superfluids

abstract:
  Quantum phase slips are the primary excitations in one-dimensional
superfluids and superconductors at low temperatures but their existence in
ultracold quantum gases has not been demonstrated yet. We now study
experimentally the nucleation rate of phase slips in one-dimensional
superfluids realized with ultracold quantum gases, owing along a periodic
potential. We observe a crossover between a regime of temperature-dependent
dissipation at small velocity and interaction and a second regime of
velocity-dependent dissipation at larger velocity and interaction. This
behavior is consistent with the predicted crossover from thermally-assisted
quantum phase slips to purely quantum phase slips.


title:
Reversibility and hysteresis of the sharp yielding transition of a
  colloidal glass under oscillatory shear

abstract:
  The mechanical response of glasses remains challenging to understand. Recent
results indicate that the oscillatory rheology of soft glasses is accompanied
by a sharp non-equilibrium transition in the microscopic dynamics. Here, we use
simultaneous x-ray scattering and rheology to investigate the reversibility and
hysteresis of the sharp sharp symmetry change from anisotropic solid to
isotropic liquid dynamics observed in the oscillatory shear of colloidal
glasses [D. V. Denisov, M. T. Dang, B. Struth, A. Zaccone, and P. Schall, Sci.
Rep. 5, 14359 (2015)]. We use strain sweeps with increasing and decreasing
strain amplitude to show that, in analogy to equilibrium transitions, this
sharp symmetry change is reversible and exhibits systematic frequency-dependent
hysteresis. Using the non-affine response formalism of amorphous solids, we
show that these hysteresis effects arise from frequency-dependent non-affine
structural cage rearrangements at large strain. These results consolidate the
first-order like nature of the oscillatory shear transition and quantify
related hysteresis effects both via measurements and theoretical modelling.


title: Cellular approximations of fusion systems

abstract:
  In this paper we study the cellularization of classifying spaces of saturated
fusion systems with respect to classifying spaces of finite $p$-groups. We give
explicit criteria to decide when a classifying space is cellular and we give
explicit computations for a family of exotic examples.


title: Regularity and Energy Conservation for the Compressible Euler Equations

abstract:
  We give sufficient conditions on the regularity of solutions to the
inhomogeneous incompressible Euler and the compressible isentropic Euler
systems in order for the energy to be conserved. Our strategy relies on
commutator estimates similar to those employed by P. Constantin et al. for the
homogeneous incompressible Euler equations.


title: A quaternionic analogue of the Segal-Bargmann transform

abstract:
  The Bargmann-Fock space of slice hyperholomorphic functions is recently
introduced by Alpay, Colombo, Sabadini and Salomon. In this paper, we
reconsider this space and present a direct proof of its independence of the
slice. We also introduce a quaternionic analogue of the classical
Segal-Bargmann transform and discuss some of its basic properties. The explicit
expression of its inverse is obtained and the connection to the left
one-dimensional quaternionic Fourier transform is given.


title:
Illustrative view on the magnetocrystalline anisotropy of adatoms and
  monolayers

abstract:
  Even though it has been known for decades that the magnetocrystalline
anisotropy is linked to the spin-orbit coupling (SOC), the mechanism how it
arises for specific systems is still subject of debate. We focused on finding
markers of SOC in the density of states (DOS) and on employing them for
understanding the source of magnetocrystalline anisotropy for the case of
adatoms and monolayers. Fully relativistic ab-initio KKR-Green function
calculations were performed for Fe, Co, and Ni adatoms and monolayers on
Au(111) to investigate changes in the orbital-resolved DOS due to a rotation of
magnetization. In this way one can see that a significant contribution to the
magnetocrystalline anisotropy for adatoms comes from pushing of the SOC-split
states above or below the Fermi level. As a result of this, the
magnetocrystalline anisotropy energy crucially depends on the position of the
energy bands of the adatom with respect to the Fermi level of the substrate.
This view is supported by model crystal field Hamiltonian calculations.


title:
Moment Expansion to the Memory Function for Generalized Drude Scattering
  rate

abstract:
  The memory function formalism is an important tool to evaluate the frequency
dependent electronic conductivity. It is previously used within some
approximations in the case of electrons interacting with various other degrees
of freedom in metals with great success. However, one needs to go beyond those
approximations as the interaction strengths become stronger. In this work, we
propose a systematic expansion of the memory function involving its various
moments. We calculate the higher order contribution to the generalized Drude
scattering rate in case of electron-impurity interactions. Further we compare
our results with the results from previously studied lowest order calculations.
We find larger contributions from the higher moments in the low frequency
regime and also in the case of larger interaction strength.


title:
Dielectric anomalies and magnetodielectric coupling behavior of single
  crystalline Ca3Co2O6, a geometrically frustrated magnetic spin-chain system

abstract:
  The dielectric behavior of the single crystals of the spin-chain system
Ca3Co2O6, undergoing geometrically frustrated antiferromagnetic ordering below
25 K, has been investigated as a function of temperature and magnetic field (H)
and compared with magnetization (M) behavior. The results provide evidence for
anisotropic magnetodielectric (MDE) coupling in this compound. Ac
susceptibility exhibits a strong frequency dependence for H parallel c with
changes of this feature with the application of external dc magnetic field. No
feature in ac susceptibility could be observed for H perpendicular c, thereby
providing evidence for strong anisotropic spin-glass behavior. Interestingly,
the strong frequency dependence in dielectric is present for both the
crystallographic directions (E parallel c and E perpendicular c where E is the
electric field) with a negligible influence of H, despite the existence of MDE
coupling. This result appears to suggest different dynamics of electric dipole
and spin-glass, although they are coupled with each other. In addition,
interestingly, there is also a step at one-third of high-(magnetic) field value
of MDE at some temperatures tracking a similar step in M(H). This work also
confirms following unusual features reported on polycrystals, when measured
along c-axis. The dielectric constant exhibits a broad peak around 50-130 K
when the electric field is applied along the spin-chain (crystallographic c
direction); however this feature is essentially absent for the perpendicular
orientation. This finding supports the role of incipient spin-chain ordering to
induce magnetodielectric coupling. There is a signature of magnetoelectric
phase coexistence when the magnetic field is applied along the spin-chain
irrespective of the direction of applied electric field.


title: Talbot effect for exciton-polaritons

abstract:
  We demonstrate, experimentally and theoretically, a Talbot effect for hybrid
light-matter waves -- exciton-polariton condensate formed in a semiconductor
microcavity with embedded quantum wells. The characteristic 'Talbot carpet' is
produced by loading the exciton-polariton condensate into a microstructured one
dimensional periodic array of mesa traps, which creates an array of sources for
coherent polariton flow in the plane of the quantum wells. The spatial
distribution of the Talbot fringes outside the mesas mimics the near-field
diffraction of a monochromatic wave on a periodic amplitude and phase grating
with the grating period comparable to the wavelength. Despite the lossy nature
of the polariton system, the Talbot pattern persists for distances exceeding
the size of the mesas by an order of magnitude.


title: Local shortcut to adiabaticity for quantum many-body systems

abstract:
  We study the environment assisted local transitionless dynamics in closed
spin systems driven through quantum critical points. In general shortcut to
adaiabaticity (STA) in quantum critical systems requires highly non-local
control Hamiltonians. In this work we develop an approach to achieve local
shortcuts to adiabaticity (LSTA) in spin chains, using local control fields
which scale polynomially with the system size, following universal critical
exponents. We relate the control fields to reduced fidelity susceptibility and
use transverse Ising model in one dimension to exemplify our generic results.
We also extend our analysis to achieve LSTA in central spin models.


title: Photospheric Emission in Gamma-Ray Bursts

abstract:
  A major breakthrough in our understanding of gamma-ray bursts (GRB) prompt
emission physics occurred in the last few years, with the realization that a
thermal component accompanies the over-all non-thermal prompt spectra. This
thermal part is important by itself, as it provides direct probe of the physics
in the innermost outflow regions. It further has an indirect importance, as a
source of seed photons for inverse-Compton scattering, thereby it contributes
to the non-thermal part as well. In this short review, we highlight some key
recent developments. Observationally, although so far it was clearly identified
only in a minority of bursts, there are indirect evidence that thermal
component exists in a very large fraction of GRBs, possibly close to 100%.
Theoretically, the existence of thermal component have a large number of
implications as a probe of underlying GRB physics. Some surprising implications
include its use as a probe of the jet dynamics, geometry and magnetization.


title: "Conjectural" links in complex networks

abstract:
  This paper introduces the concept of Conjectural Link for Complex Networks,
in particular, social networks. Conjectural Link we understand as an implicit
link, not available in the network, but supposed to be present, based on the
characteristics of its topology. It is possible, for example, when in the
formal description of the network some connections are skipped due to errors,
deliberately hidden or withdrawn (e.g. in the case of partial destruction of
the network). Introduced a parameter that allows ranking the Conjectural Link.
The more this parameter - the more likely that this connection should be
present in the network. This paper presents a method of recovery of partially
destroyed Complex Networks using Conjectural Links finding. Presented two
methods of finding the node pairs that are not linked directly to one another,
but have a great possibility of Conjectural Link communication among
themselves: a method based on the determination of the resistance between two
nodes, and method based on the computation of the lengths of routes between two
nodes. Several examples of real networks are reviewed and performed a
comparison to know network links prediction methods, not intended to find the
missing links in already formed networks.


title:
Short-term time series prediction using Hilbert space embeddings of
  autoregressive processes

abstract:
  Linear autoregressive models serve as basic representations of discrete time
stochastic processes. Different attempts have been made to provide non-linear
versions of the basic autoregressive process, including different versions
based on kernel methods. Motivated by the powerful framework of Hilbert space
embeddings of distributions, in this paper we apply this methodology for the
kernel embedding of an autoregressive process of order $p$. By doing so, we
provide a non-linear version of an autoregressive process, that shows increased
performance over the linear model in highly complex time series. We use the
method proposed for one-step ahead forecasting of different time-series, and
compare its performance against other non-linear methods.


title: Fermionic T-duality in fermionic double space

abstract:
  In this article we offer the interpretation of the fermionic T-duality of the
type II superstring theory in double space. We generalize the idea of double
space doubling the fermionic sector of the superspace. In such doubled space
fermionic T-duality is represented as permutation of the fermionic coordinates
$\theta^\alpha$ and $\bar\theta^\alpha$ with the corresponding fermionic T-dual
ones, $\vartheta_\alpha$ and $\bar\vartheta_\alpha$, respectively. Demanding
that T-dual transformation law has the same form as inital one, we obtain the
known form of the fermionic T-dual NS-R i R-R background fields. Fermionic
T-dual NS-NS background fields are obtained under some assumptions. We conclude
that only symmetric part of R-R field strength and symmetric part of its
fermionic T-dual contribute to the fermionic T-duality transformation of
dilaton field and analyze the dilaton field in fermionic double space. As a
model we use the ghost free action of type II superstring in pure spinor
formulation in approximation of constant background fields up to the quadratic
terms.


title: Similarity of the Temperature Profile formed by Fluid Flow along a Wall

abstract:
  A new approach to the study of similarity of temperature profiles is
presented. It is applicable for any 2-D fluid flow along an isothermal heated
(cooled) wall. The approach is based on a simple concept; the area under a set
of scaled temperature profile curves that show similar behavior must be equal.
This leads to a new integral-based definition of temperature profile
similarity. By taking simple area integrals of the scaled temperature profile
and its first derivative, we also obtain a number of new results pertaining to
similarity of the temperature profiles. For example, it is shown that if
similarity exists, then: 1) the similarity temperature and length scaling
parameters are interdependent, 2) the thermal displacement thickness must be a
similar length scaling parameter, and 3) the temperature scaling parameter must
be proportional to the free stream minus wall temperature values.


title: Quasi-cyclic subcodes of cyclic codes

abstract:
  We completely characterize possible indices of quasi-cyclic subcodes in a
cyclic code for a very broad class of cyclic codes. We present enumeration
results for quasi-cyclic subcodes of a fixed index and show that the problem of
enumeration is equivalent to enumeration of certain vector subspaces in finite
fields. In particular, we present enumeration results for quasi-cyclic subcodes
of the simplex code and duals of certain BCH codes. Our results are based on
the trace representation of cyclic codes.


title:
Pairwise Stability in Two Sided Market with Strictly Increasing
  Valuation Functions

abstract:
  This paper deals with two-sided matching market with two disjoint sets, i.e.
the set of buyers and the set of sellers. Each seller can trade with at most
with one buyer and vice versa. Money is transferred from sellers to buyers for
an indivisible goods that buyers own. Valuation functions, for participants of
both sides, are represented by strictly increasing functions with money
considered as discrete variable. An algorithm is devised to prove the existence
of stability for this model.


title:
The inductive blockwise Alperin weight condition for $G_2(q)$ and
  $^3D_4(q)$

abstract:
  The inductive blockwise Alperin weight condition is a system of conditions
whose verification for all non-abelian finite simple groups would imply the
blockwise Alperin weight conjecture. We establish this condition for the groups
$G_2(q)$, $q \geq 5$, and $^3D_4(q)$ for all primes dividing their order.


title:
Breakdown of Nonlinear Elasticity in Amorphous Solids at Finite
  Temperatures

abstract:
  It is known by now that amorphous solids at zero temperature do not possess a
nonlinear elasticity theory: besides the shear modulus which exists, all the
higher order coefficients do not exist in the thermodynamic limit. Here we show
that the same phenomenon persists up to temperatures comparable to the glass
transition. The zero temperature mechanism due to the prevalence of dangerous
plastic modes of the Hessian matrix is replaced by anomalous stress
fluctuations that lead to the divergence of the variances of the higher order
elastic coefficients. The conclusion is that in amorphous solids elasticity can
never be decoupled from plasticity: the nonlinear response is very
substantially plastic.


title: Eddy current imaging with an atomic radio-frequency magnetometer

abstract:
  We use a radio-frequency $^{85}$Rb alkali-vapor cell magnetometer based on a
paraffin-coated cell with long spin-coherence time and a small, low-inductance
driving coil to create highly resolved conductivity maps of different objects.
We resolve sub-mm features in conductive objects, we characterize the frequency
response of our technique, and by operating at frequencies up to 250 kHz we are
able to discriminate between differently conductive materials based on the
induced response. The method is suited to cover a wide range of driving
frequencies and can potentially be used for detecting non-metallic objects with
low DC conductivity.


title: Nonparametric imputation method for nonresponse in surveys

abstract:
  Many imputation methods are based on statistical models that assume that the
variable of interest is a noisy observation of a function of the auxiliary
variables or covariates. Misspecification of this model may lead to severe
errors in estimates and to misleading conclusions. A new imputation method for
item nonresponse in surveys is proposed based on a nonparametric estimation of
the functional dependence between the variable of interest and the auxiliary
variables. We consider the use of smoothing spline estimation within an
additive model framework to flexibly build an imputation model in the case of
multiple auxiliary variables. The performance of our method is assessed via
numerical experiments involving simulated and real data.


title:
Hardware Software Co-design for Automotive CPS using Architecture
  Analysis and Design Language

abstract:
  Modern cyber-physical systems (CPS) have a close inter-dependence between
software and physical components. Automotive embedded systems are typical CPS,
as physical chips, sensors and actuators are physical components and software
embedded within are the cyber components. The current stage of embedded systems
is highly complex in architecture design for both software and hardware. It is
common in industrial practice that high level control algorithm development and
low level code implementation on hardware platforms are developed separately
with limited shared information. However, software code and hardware
architecture become closely related with the increasing complexity. Correlated
requirements and dependencies between hardware and software are emerging
problems of industrial practice. We demonstrate in this paper a method to link
model based system design with real-time simulations and analysis of the
architecture model. This allows hardware software co-design and thus early
selection of hardware architecture.


title: Peccei-Quinn symmetry for Dirac seesaw and leptogenesis

abstract:
  We extend the DFSZ invisible axion model to simultaneously explain small
Dirac neutrino masses and cosmic matter-antimatter asymmetry. After the
Peccei-Quinn and electroweak symmetry breaking, the effective Yukawa couplings
of the Dirac neutrinos to the standard model Higgs scalar can be highly
suppressed by the ratio of the vacuum expectation value of an iso-triplet Higgs
scalar over the masses of some heavy gauge-singlet fermions, iso-doublet Higgs
scalars or iso-triplet fermions. The iso-triplet fields can carry a zero or
nonzero hypercharge. Through the decays of the heavy gauge-singlet fermions,
iso-doublet scalars or iso-triplet fermions, we can obtain a lepton asymmetry
in the left-handed leptons and an opposite lepton asymmetry in the right-handed
neutrinos. Since the right-handed neutrinos do not participate in the sphaleron
processes, the left-handed lepton asymmetry can be partially converted to a
baryon asymmetry.


title: Shortcuts to adiabaticity and applications to Quantum Computation

abstract:
  Adiabatic evolution is a powerful technique in quantum information and
computation. However, its performance is limited by the adiabatic theorem of
quantum mechanics. In this scenario, shortcuts to adiabaticity, such as
provided by the superadiabatic theory, constitute a valuable tool to speed up
the adiabatic quantum behavior. In this dissertation we introduce two different
models to perform universal superadiabatic quantum computing, which are based
on the use of shortcuts to adiabaticity by counter-diabatic Hamiltonians. The
first model is based on the use of superadiabatic quantum teleportation,
introduced in this dissertation, as a primitive to quantum computing. Thus, we
provide the counter-diabatic driving for arbitrary $n$-qubit gates. In
addition, our approach maps the counter-diabatic Hamiltonian for an arbitrary
$n$-qubit {\it gate} teleportation into the implementation of a rotated
counter-diabatic Hamiltonian for an $n$-qubit {\it state} teleportation. In the
second model we use the concept of controlled superadiabatic evolutions to show
how we can implement arbitrary $n$-controlled quantum gates. Remarkably, this
task can be performed by simple time-independent counter-diabatic Hamiltonians.
These two models can be used to design different sets of universal quantum
gates. We show that the use of the quantum speed limit suggests that the
superadiabatic time evolution is compatible with arbitrarily small time
intervals, where this arbitrariness is constrained to the energetic cost
necessary to perform the superadiabatic evolution.


title:
Reconciling Rationality and Stochasticity: Rich Behavioral Models in
  Two-Player Games

abstract:
  Two traditional paradigms are often used to describe the behavior of agents
in multi-agent complex systems. In the first one, agents are considered to be
fully rational and systems are seen as multi-player games. In the second one,
agents are considered to be fully stochastic processes and the system itself is
seen as a large stochastic process. From the standpoint of a particular agent -
having to choose a strategy, the choice of the paradigm is crucial: the most
adequate strategy depends on the assumptions made on the other agents.
  In this paper, we focus on two-player games and their application to the
automated synthesis of reliable controllers for reactive systems - a field at
the crossroads between computer science and mathematics. In this setting, the
reactive system to control is a player, and its environment is its opponent,
usually assumed to be fully antagonistic or fully stochastic. We illustrate
several recent developments aiming to breach this narrow taxonomy by providing
formal concepts and mathematical frameworks to reason about richer behavioral
models.
  The interest of such models is not limited to reactive system synthesis but
extends to other application fields of game theory. The goal of our
contribution is to give a high-level presentation of key concepts and
applications, aimed at a broad audience. To achieve this goal, we illustrate
those rich behavioral models on a classical challenge of the everyday life:
planning a journey in an uncertain environment.


title:
Descriptor transition tables for object retrieval using unconstrained
  cluttered video acquired using a consumer level handheld mobile device

abstract:
  Visual recognition and vision based retrieval of objects from large databases
are tasks with a wide spectrum of potential applications. In this paper we
propose a novel recognition method from video sequences suitable for retrieval
from databases acquired in highly unconstrained conditions e.g. using a mobile
consumer-level device such as a phone. On the lowest level, we represent each
sequence as a 3D mesh of densely packed local appearance descriptors. While
image plane geometry is captured implicitly by a large overlap of neighbouring
regions from which the descriptors are extracted, 3D information is extracted
by means of a descriptor transition table, learnt from a single sequence for
each known gallery object. These allow us to connect local descriptors along
the 3rd dimension (which corresponds to viewpoint changes), thus resulting in a
set of variable length Markov chains for each video. The matching of two sets
of such chains is formulated as a statistical hypothesis test, whereby a subset
of each is chosen to maximize the likelihood that the corresponding video
sequences show the same object. The effectiveness of the proposed algorithm is
empirically evaluated on the Amsterdam Library of Object Images and a new
highly challenging video data set acquired using a mobile phone. On both data
sets our method is shown to be successful in recognition in the presence of
background clutter and large viewpoint changes.


title:
Leptogenesis, radiative neutrino masses and inert Higgs triplet dark
  matter

abstract:
  We extend the standard model by three types of inert fields including
Majorana fermion singlets/triplets, real Higgs singlets/triplets and leptonic
Higgs doublets. In the presence of a softly broken lepton number and an exactly
conserved Z_2 discrete symmetry, these inert fields together can mediate a
one-loop diagram for a Majorana neutrino mass generation. The heavier inert
fields can decay to realize a successful leptogenesis while the lightest inert
field can provide a stable dark matter candidate. As an example, we demonstrate
the leptogenesis by the inert Higgs doublet decays. We also perform a
systematic study on the inert Higgs triplet dark matter scenario where the
interference between the gauge and Higgs portal interactions can significantly
affect the dark matter properties.


title:
A linear complementarity based characterization of the weighted
  independence number and the independent domination number in graphs

abstract:
  The linear complementarity problem is a continuous optimization problem that
generalizes convex quadratic programming, Nash equilibria of bimatrix games and
several such problems. This paper presents a continuous optimization
formulation for the weighted independence number of a graph by characterizing
it as the maximum weighted $\ell_1$ norm over the solution set of a linear
complementarity problem (LCP). The minimum $\ell_1$ norm of solutions of this
LCP is a lower bound on the independent domination number of the graph. Unlike
the case of the maximum $\ell_1$ norm, this lower bound is in general weak, but
we show it to be tight if the graph is a forest. Using methods from the theory
of LCPs, we obtain a few graph theoretic results. In particular, we provide a
stronger variant of the Lov\'{a}sz theta of a graph. We then provide sufficient
conditions for a graph to be well-covered, i.e., for all maximal independent
sets to also be maximum. This condition is also shown to be necessary for
well-coveredness if the graph is a forest. Finally, the reduction of the
maximum independent set problem to a linear program with (linear)
complementarity constraints (LPCC) shows that LPCCs are hard to approximate.


title:
New analysis for the correlation between gravitational waves and
  neutrino detectors during SN1987A

abstract:
  Two major problems, still associated with the SN1987A, are: a) the signals
observed with the gravitational waves detectors, b) the duration of the
collapse. Indeed, a) the sensitivity of the gravitational wave detectors seems
to be small for detecting gravitational waves and, b) while some experimental
data indicate a duration of order of hours, most theories assume that the
collapse develops in a few seconds. Since recent data of the X-ray NuSTAR
satellite show a clear evidence of an asymmetric collapse, we have revisited
the experimental data recorded by the underground and gravitational wave
detectors running during the SN1987A. New evidence is shown that con rms
previous results, namely that the data recorded by the gravitational wave
detectors running in Rome and in Maryland are strongly correlated with the data
of both the Mont Blanc and the Kamiokande detectors, and that the correlation
extends over a long period of time (one or two hours) centered at the Mont
Blanc time. This result indicates that also Kamiokande detected neutrinos at
the Mont Blanc time, and these interactions were not identi ed because not
grouped in a burst.


title:
Excitation of fundamental shear horizontal wave by using face-shear
  (d36) piezoelectric ceramics

abstract:
  The fundamental shear horizontal (SH0) wave in plate-like structures is
extremely useful for non-destructive testing (NDT) and structural health
monitoring (SHM) as it is non-dispersive. However, currently the SH0 wave is
usually excited by electromagnetic acoustic transducers (EMAT) whose energy
conversion efficiency is fairly low. The face-shear (d36) mode piezoelectrics
is more promising for SH0 wave excitation but this mode cannot appear in
conventional piezoelectric ceramics. Recently, by modifying the symmetry of
poled PbZr1-xTixO3 (PZT) ceramics via ferroelastic domain engineering, we
realized the face-shear d36 mode in both soft and hard PZT ceramics. In this
work, we further improved the face-shear properties of PZT-4 and PZT-5H
ceramics via lateral compression under elevated temperature. It was found that
when bonded on a 1 mm-thick aluminum plate, the d36 type PZT-4 exhibited better
face-shear performance than PZT-5H. We then successfully excite SH0 wave in the
aluminum plate using a face-shear PZT-4 square patch and receive the wave using
a face-shear PMN-PT patch. The frequency response and directionality of the
excited SH0 wave were also investigated. The SH0 wave can be dominate over the
Lamb waves (S0 and A0 waves) from 160 kHz to 280 kHz. The wave amplitude
reaches its maxima along the two main directions (0{\deg} and 90{\deg}). The
amplitude can keep over 80% of the maxima when the deviate angle is less than
30{\deg}, while it vanishes quickly at the 45{\deg} direction. The excited SH0
wave using piezoelectric ceramics could be very promising in the fields of NDT
and SHM.


title:
Are the discretised lognormal and hooked power law distributions
  plausible for citation data?

abstract:
  There is no agreement over which statistical distribution is most appropriate
for modelling citation count data. This is important because if one
distribution is accepted then the relative merits of different citation-based
indicators, such as percentiles, arithmetic means and geometric means, can be
more fully assessed. In response, this article investigates the plausibility of
the discretised lognormal and hooked power law distributions for modelling the
full range of citation counts, with an offset of 1. The citation counts from 23
Scopus subcategories were fitted to hooked power law and discretised lognormal
distributions but both distributions failed a Kolmogorov-Smirnov goodness of
fit test in over three quarters of cases. The discretised lognormal
distribution also seems to have the wrong shape for citation distributions,
with too few zeros and not enough medium values for all subjects. The cause of
poor fits could be the impurity of the subject subcategories or the presence of
interdisciplinary research. Although it is possible to test for subject
subcategory purity indirectly through a goodness of fit test in theory with
large enough sample sizes, it is probably not possible in practice. Hence it
seems difficult to get conclusive evidence about the theoretically most
appropriate statistical distribution.


title: Classical communication cost of quantum steering

abstract:
  Quantum steering is observed when performing appropriate local measurements
on an entangled state. Here we discuss the possibility of simulating
classically this effect, using classical communication instead of entanglement.
We show that infinite communication is necessary for exactly simulating
steering for any pure entangled state, as well as for a class of mixed
entangled states. Moreover, we discuss the communication cost of steering for
general entangled states, as well as approximate simulation. Our findings
reveal striking differences between Bell nonlocality and steering, and provide
a natural way of measuring the strength of the latter.


title: EPR Steering inequalities with Communication Assistance

abstract:
  In this paper, we investigate the communication cost of reproducing
Einstein-Podolsky-Rosen (EPR) steering correlations arising from bipartite
quantum systems. We characterize the set of bipartite quantum states which
admits a local hidden state model augmented with $c$ bits of classical
communication from an untrusted party (Alice) to a trusted party (Bob). In case
of one bit of information ($c=1$), we show that this set has a nontrivial
intersection with the sets admitting a local hidden state and a local hidden
variables model for projective measurements. On the other hand, we find that an
infinite amount of classical communication is required from an untrusted Alice
to a trusted Bob to simulate the EPR steering correlations produced by a
two-qubit maximally entangled state. It is conjectured that a state-of-the-art
quantum experiment would be able to falsify two bits of communication this way.


title:
Criteria for extensional necking instability in complex fluids and soft
  solids. Part I: imposed Hencky strain rate protocol

abstract:
  We study the necking dynamics of a filament of complex fluid or soft solid in
uniaxial tensile stretching at constant imposed Hencky strain rate
$\dot\varepsilon$, by means of linear stability analysis and nonlinear (slender
filament) simulations. We demonstrate necking to be an intrinsic flow
instability that arises as an inevitable consequence of the constitutive
behaviour of essentially any material (with a possible rare exception, which we
outline). We derive criteria for the onset of necking that are reportable
simply in terms of characteristic signatures in the shapes of the
experimentally measured rheological response functions, and should therefore
apply universally to all materials. As evidence of their generality, we
numerically show them to hold in six popular constitutive models of polymers
and soft glasses. Two distinct modes of necking instability are predicted. The
first is relatively gentle, and sets in when the tensile stress signal first
curves down as a function of the time $t$ (or accumulated strain
$\epsilon=\dot\varepsilon t$) since the inception of the flow. The second is
more violent, and sets in when a carefully defined `elastic derivative' of the
tensile force first slopes down as a function of $t$ (or $\dot\varepsilon$). In
the limit of fast flow $\dot\varepsilon\tau\to\infty$, where $\tau$ is the
material's characteristic stress relaxation time, this second mode reduces to
the Consid\'ere criterion for necking in solids. However we show that the
Consid\'ere criterion fails to correctly predict the onset of necking in any
viscoelastic regime of finite imposed $\dot\varepsilon\tau$. Finally, we
elucidate the way these modes of instability manifest themselves in entangled
linear polymers, wormlike micelles and branched polymers. We demonstrate four
distinct regimes as a function of imposed strain rate, consistent with
experimental master curves.


title: Self-gravitating systems of ideal gases in the 1PN approximation

abstract:
  We obtain the Maxwell-J\"uttner distribution function at first order in the
post-Newtonian approximation within the framework of general relativity. Taking
into account the aforesaid distribution function, we compute the particle
four-flow and energy-momentum tensor. We focus on the search of static
solutions for the gravitational potentials with spherical symmetry. In doing
so, we obtain the density, pressure and gravitational potential energy profiles
in terms of dimensionless radial coordinate by solving the aforesaid equations
numerically. In particular, we find the parametric profile for the equation of
state $p/\rho$ in terms of the dimensionless radial coordinate. Due to its
physical relevance, we also find the galaxy rotation curves using the
post-Newtonian approximation. We join two different kinds of static solutions
in order to account for the linear regime near the center and the typical
flatten behavior at large radii as well.


title: Light deflection by light: Effect of incidence angle and inhomogeneity

abstract:
  We study the angular deflection of the circular polarized components of a
linearly polarized probe field in a weakly birefringent atomic system in tripod
configuration. A spatially inhomogeneous control field incident obliquely onto
an atomic vapor cell facilitates a large angular divergence between circular
components. We show that the angular resolution can be dynamically controlled
by optimally choosing the angle of incidence and the transverse profile of the
control beam. For instance, by employing a Laguerre-Gaussian profile of the
control field, one can impart a large angular divergence to the circular
components close to the entry face of the atomic vapor cell. We further
demonstrate how such a medium causes the focusing and refocusing of the probe
field, thereby acting as a lens with multiple foci. The absorption in the
medium remains negligible at resonance due to electromagnetically induced
transparency (EIT).


title: Brill-Noether theory for cyclic covers

abstract:
  The Brill-Noether Theorem gives necessary and sufficient conditions for the
existence of a linear series. Here we consider a general n-fold, etale cyclic
cover p of a curve C of genus g and investigate for which numbers r,d a linear
series of dimension r and degree d exists on the covering curve. For r=1 this
gives gonality. Using degeneration to a special singular example (containing a
Castelnuovo canonical curve) and the theory of of limit linear series for
tree-like curves we show that the Pl\"ucker formula yields a necessary
condition for the existence of a linear series (of dimension r, degree d) which
is only slightly weaker than the sufficient condition given by the result of
Kleimann and Laksov, for all n,r,d.


title:
Convergence to equilibrium for Fokker-Planck equation with a general
  force field

abstract:
  The aim of this paper is to study the convergence of the solution of the
Fokker-Planck equation to the associated stationary state when time goes to
infinity. The force field which we consider here is of a general structure,
that is it may not derive from a potential. The proof is based on an adequate
splitting L = B+A of the Fokker-Planck operator L and the use of Krein-Rutmann
theory.


title:
Linear complexity of quaternary sequences over Z_4 derived from
  generalized cyclotomic classes modulo 2p

abstract:
  We determine the exact values of the linear complexity of 2p-periodic
quaternary sequences over Z_4 (the residue class ring modulo 4) defined from
the generalized cyclotomic classes modulo 2p in terms of the theory of of
Galois rings of characteristic 4, where p is an odd prime. Compared to the case
of quaternary sequences over the finite field of order 4, it is more dificult
and complicated to consider the roots of polynomials in Z_4[X] due to the zero
divisors in Z_4 and hence brings some interesting twists. We answer an open
problem proposed by Kim, Hong and Song.


title:
Existence and stability of planar shocks of viscous scalar conservation
  laws with space-periodic flux

abstract:
  The goal of this paper is to prove the existence and stability of shocks for
viscous scalar conservation laws with space periodic flux, in the
multi-dimensional case. Such a result had been proved by the first author in
one space dimension, but the extension to a multi-dimensional setting makes the
existence proof non-trivial. We construct approximate solutions by restricting
the size of the domain and then passing to the limit as the size of the domain
goes to infinity. One of the key steps is a " normalization " procedure, which
ensures that the limit objects obtained by the approximation scheme are indeed
shocks. The proofs rely on elliptic PDE theory rather than ODE arguments as in
the 1d case. Once the existence of shocks is proved, their stability follows
from classical arguments based on the theory of dynamical systems.


title:
Density stability for some L\'evy-driven Stochastic Differential
  Equations

abstract:
  We consider a Stochastic Differential Equation driven by a L\'evy process
whose L\'evy measure satisfy a tempered stable domination. We study how a
perturbation of the coefficients reflects on the density of the solution. We
quantify the distance between the densities in term of the proximity of the
coefficients. This extend to the stable case the works of [KKM15], where the
noise is Gaussian.


title: An existence result for the steady rotating Prandtl equation

abstract:
  We consider a steady, geophysical 2D fluid in a domain, and focus on its
western boundary layer, which is formally governed by a variant of the Prandtl
equation. By using the von Mises change of variables, we show that this
equation is well-posed under the assumption that the trace of the interior
stream function has large variations, and that the variations in the coastline
profile are moderate.


title: Infinite order corks

abstract:
  We construct a compact, contractible 4-manifold $C$, an infinite-order
self-diffeomorphism $f$ of its boundary, and a smooth embedding of $C$ into a
closed, simply connected 4-manifold $X$, such that the manifolds obtained by
cutting $C$ out of $X$ and regluing it by powers of $f$ are all pairwise
nondiffeomorphic. The manifold $C$ can be chosen from among infinitely many
homeomorphism types, all obtained by attaching a 2-handle to the meridian of a
thickened knot complement.


title:
On the coupling of regularization techniques and the boundary element
  method for a hemivariational inequality modelling a delamination problem

abstract:
  In this paper, we couple regularization techniques of nondifferentiable
optimization with the h-version of the boundary element method (h-BEM) to solve
nonsmooth variational problems arising in contact mechanics. As a model example
we consider the delamination problem. The variational formulation of this
problem leads to a hemivariational inequality (HVI)with a nonsmooth functional
defined on the contact boundary. This problem is first regularized and then
discretized by a h-BEM. We prove convergence of the h-BEM Galerkin solution of
the regularized problem in the energy norm, provide an a-priori error estimate
and give a numerical example.


title: Amorphization of a crystalline solid by plastic deformation

abstract:
  We demonstrate that plastic deformation in solids is associated with a
dynamic transition that is reminiscent to the transition from a superconducting
to a mixed phase in Type II superconductors. We report analytic calculations,
extensive molecular dynamics and sequential umbrella sampling Monte Carlo
simulations of a two dimensional triangular crystalline solid undergoing
plastic deformation under strain. The solid consists of particles connected by
harmonic springs. Non-affine displacement fluctuations of the solid are
enhanced using an external field, causing a rich deformation behaviour. The
external field leads to a mixed phase, where defect and stress-free
crystallites are surrounded by a network of amorphous regions with large local
internal stress --- a "stress Meissner" effect. The transition shows slow
ageing dynamics caused by the presence of many competing, non-crystalline
free-energy minima. Under uniform uniaxial strain, this amorphization
transition gives rise to irreversible plastic deformation with the amorphous
regions appearing as band-like structures. Our results may be checked by
careful experiments on colloidal crystals using holographic optical tweezers.


title: Polariton condensates at room temperature

abstract:
  We review the recent developments of the polariton physics in microcavities
featuring the exciton-photon strong coupling at room-temperature, and leading
to the achievement of room-temperature polariton condensates. Such cavities
embed active layers with robust excitons that present a large binding energy
and a large oscillator strength, i.e. wide bandgap inorganic or organic
semiconductors, or organic molecules. These various systems are compared, in
terms of figures of merit and of common features related to their strong
oscillator strength. The various demonstrations of polariton laser are
compared, as well as their condensation phase diagrams. The room-temperature
operation indeed allows a detailed investigation of the thermodynamic and
out-of-equilibrium regimes of the condensation process. The crucial role of the
spatial dynamics of the condensate formation is discussed, as well as the
debated issue of the mechanism of stimulated relaxation from the reservoir to
the condensate under non-resonant excitation. Finally the prospects of
polariton devices are presented.


title:
The redshift distribution of dusty star forming galaxies from the SPT
  survey

abstract:
  We use the Atacama Large Millimeter/submillimeter Array (ALMA) in Cycle 1 to
determine spectroscopic redshifts of high-redshift dusty star-forming galaxies
(DSFGs) selected by their 1.4mm continuum emission in the South Pole Telescope
(SPT) survey. We present ALMA 3mm spectral scans between 84-114GHz for 15
galaxies and targeted ALMA 1mm observations for an additional eight sources.
Our observations yield 30 new line detections from CO, [CI] , [NII] , H_2O and
NH_3. We further present APEX [CII] and CO mid-J observations for seven sources
for which only a single line was detected in spectral-scan data from ALMA Cycle
0 or Cycle 1. We combine the new observations with previously published and new
mm/submm line and photometric data of the SPT-selected DSFGs to study their
redshift distribution. The combined data yield 39 spectroscopic redshifts from
molecular lines, a success rate of >85%. Our sample represents the largest data
set of its kind today and has the highest spectroscopic completeness among all
redshift surveys of high-z DSFGs. The median of the redshift distribution is
z=3.9+/-0.4, and the highest-redshift source in our sample is at z=5.8. We
discuss how the selection of our sources affects the redshift distribution,
focusing on source brightness, selection wavelength, and strong gravitational
lensing. We correct for the effect of gravitational lensing and find the
redshift distribution for 1.4mm-selected sources with a median redshift of
z=3.1+/-0.3. Comparing to redshift distributions selected at shorter
wavelengths from the literature, we show that selection wavelength affects the
shape of the redshift distribution.