title:
Deeply Embedded Protostellar Population in the Central Molecular Zone
  Suggested by H$_2$O Masers and Dense Cores

abstract:
  The Central Molecular Zone (CMZ), usually referring to the inner 500 pc of
the Galaxy, contains a dozen of massive ($\sim10^5$ $M_\odot$) molecular
clouds. Are these clouds going to actively form stars like Sgr B2? How are they
affected by the extreme physical conditions in the CMZ, such as strong
turbulence? Here we present a first step towards answering these questions.
Using high-sensitivity, high angular resolution radio and (sub)millimeter
observations, we studied deeply embedded star formation in six massive clouds
in the CMZ, including the 20 and 50 km s$^{-1}$ clouds, Sgr B1 off (as known as
dust ridge clouds e/f), Sgr C, Sgr D, and G0.253-0.016. The VLA water maser
observations suggest a population of deeply embedded protostellar candidates,
many of which are new detections. The SMA 1.3 mm continuum observations reveal
peaks in dust emission associated with the masers, suggesting the existence of
dense cores. While our findings confirm that clouds such as G0.253-0.016 lack
internal compact substructures and are quiescent in terms of star formation,
two clouds (the 20 km s$^{-1}$ cloud and Sgr C) stand out with clusters of
water masers with associated dense cores which may suggest a population of
deeply embedded protostars at early evolutionary phases. Follow-up observations
with VLA and ALMA are necessary to confirm their protostellar nature.


title:
Phase transition in anisotropic holographic superfluids with arbitrary
  $z$ and $\alpha$

abstract:
  Einstein-dilaton-$U(2)$ gauge field theory is considered in a spacetime
characterised by $\alpha$ and $z$, which are the hyperscaling violation factor
and the dynamical critical exponent respectively. We obtain the critical values
of chemical potential $\mu_c$ that is defined on its boundary dual fluid and
derives phase transition from spatially isotropic to anisotropic phase for the
various values of the $\alpha$ and $z$. To do so, we first apply
Sturm-Liouville theory and estimate the upper bounds of the critical values of
the chemical potential. We also employ a numerical method in the ranges of $1
\leq z \leq 4$ and $0 \leq \alpha \leq 4$ to check if the Sturm-Liouville
method correctly estimates the critical values of the chemical po10 percent
error ranges. Finally, we compute free energy density of the dual fluid by
using its gravity dual and check if the system shows phase transition at the
critical values of the chemical potential $\mu_c$ for the given parameter
region of $\alpha$ and $z$. Interestingly, it is observed that the anisotropic
phase is more favoured than the isotropic phase for small values of $z$ and
$\alpha$. However, for large values of $z$ and $\alpha$, the anisotropic phase
is not favoured.tential. It turns out that the two methods are agreed within


title:
Clapeyron equation and phase equilibrium properties in higher
  dimensional charged topological dilaton AdS black holes with a nonlinear
  source

abstract:
  Using Maxwell's equal area law, we discuss the phase transition of higher
dimensional charged topological dilaton AdS black holes with a nonlinear
source. The coexisting region of the two phases is found and we depict the
coexistence region in $P-v$ diagrams. The two-phase equilibrium curves in $P-T$
diagrams are plotted, and we take the first order approximation of volume $v$
in the calculation. To better compare with a general thermodynamic system, the
Clapeyron equation is derived for higher dimensional charged topological black
hole with a nonlinear source. The latent heat of isothermal phase transition is
investigated. We also study the effect of the parameters of the black hole on
the region of two-phases coexistence. The results show that the black hole may
go through a small-large phase transition similar to those of usual non-gravity
thermodynamic systems.


title:
First-principles studies of the Optical anisotropy of R3 space group
  chalcogenides crystal AX2MQ6

abstract:
  In order to explain the reason that all the sythesised \ce{AX2MQ6}
chalcogenides compounds are phase-matching while isomorphic chalcogenides
compounds \ce{AX4M5Q12} are not phase-matched materials. The linear optical
property birefringence and non-linear optical property of $R3$ space group
crystals \ce{AX2MQ6} have been calculated to compare with \ce{AX4M5Q12}. Their
Electron Localization Function(ELF) was calculated to show that the acentricity
of the bonds on $sp^3$ hybridization \ce{Q^2-} ions is the main origin of
optical anisotropy. To quantificat the acentricity, a geometric parameter
dihedral angle between tetrahedral undersides and xy-planes was defined. We
find theoretically the birefringence depend on the defined geometric parameter
and ion radius. This relation between birefringence and structure resonalbly
explain the abnormal difference of birefringence of isostructural \ce{AX2MQ6}
and \ce{AX4M5Q12} and useful for exploring new phase-matching IR-NLO crystals.


title: How many delta-matroids are there?

abstract:
  We give upper and lower bounds on the number of delta-matroids, and on the
number of even delta-matroids.


title:
Anomalous Hall effect and spin orbit torques in MnGa/IrMn films:
  Modification from strong spin Hall effect of antiferromagnet

abstract:
  We report systematic measurements of anomalous Hall effect(AHE) and spin
orbit torques(SOT) in MnGa/IrMn films,, in which a single MnGa epitaxial layer
reveals obvious orbital two-channel Kondo (2CK) effect. As increasing the
thickness of the antiferromagnet IrMn, the strong spin Hall effect(SHE)has
gradually suppressed the orbital 2CK effect and modified the AHE of MnGa.A
scaling involving multiple competing scattering mechanisms has been used to
distinguish different contributions to the modified AHE. Finally, the sizeable
SOT in the MnGa/IrMn films induced by the strong SHE of IrMn have been
investigated.The IrMn layer also supplies an in-plane exchange bias field and
enables nearly field-free magnetization reversal.


title: Multiferroic Bi$_2$NiMnO$_6$ Thin Films: A Computational Prediction

abstract:
  We report first-principles calculations for one of the few materials that is
believed to be a ferroelectric ferromagnet, Bi$_2$NiMnO$_6$. Our calculations
show that, contrary to what it has been reported so far, bulk Bi$_2$NiMnO$_6$
does not have a polarization. Instead, like BiMnO$_3$, it crystallizes into a
centrosymmetric structure with space group $C2/c$. We also predict that
Bi$_2$NiMnO$_6$ will indeed be a ferroelectric ferromagnet if it is grown as an
epitaxial film on a substrate with in-plane square symmetry and a lattice
constant around 4~\AA, such as BaTiO$_3$ or PbZr$_{1-x}$Ti$_{x}$O$_{3}$.


title:
Cosmological Forecasts for Combined and Next Generation Peculiar
  Velocity Surveys

abstract:
  Peculiar velocity surveys present a very promising route to measuring the
growth rate of large-scale structure and its scale dependence. However,
individual peculiar velocity surveys suffer from large statistical errors due
to the intrinsic scatter in the relations used to infer a galaxy's true
distance. In this context we use a Fisher Matrix formalism to investigate the
statistical benefits of combining multiple peculiar velocity surveys. We find
that for all cases we consider there is a marked improvement on constraints on
the linear growth rate $f\sigma_{8}$. For example, the constraining power of
only a few peculiar velocity measurements is such that the addition of the
2MASS Tully-Fisher survey (containing only $\sim2,000$ galaxies) to the full
redshift and peculiar velocity samples of the 6-degree Field Galaxy Survey
(containing $\sim 110,000$ redshifts and $\sim 9,000$ velocities) can improve
growth rate constraints by $\sim20\%$. Furthermore, the combination of the
future TAIPAN and WALLABY+WNSHS surveys has the potential to reach a $\sim3\%$
error on $f\sigma_{8}$, which will place tight limits on possible extensions to
General Relativity. We then turn to look at potential systematics in growth
rate measurements that can arise due to incorrect calibration of the peculiar
velocity zero-point and from scale-dependent spatial and velocity bias. For
next generation surveys, we find that neglecting velocity bias in particular
has the potential to bias constraints on the growth rate by over $5\sigma$, but
that an offset in the zero-point has negligible impact on the velocity power
spectrum.


title: Second-order Fermionic Interference with Independent Photons

abstract:
  The experimental study of the second-order interference with fermions is much
less than the one with bosons since it is much more difficult to do experiments
with fermions than with photons. Based on the conclusion that the behavior of
two identical classical particles has exactly half fermionic and half bosonic
characteristics (PRA \textbf{88}, 012130 (2013)), we have studied the
second-order interference of fermions via the second-order interference of
photons in Hanbury Brown-Twiss and Hong-Ou-Mandel interferometers,
respectively. The experimental results are consistent with the theoretical
predictions, which serve as an efficient guidance for the future interference
experiments with fermions. The employed method offers an interesting and
convenient way to study the coherence of fermions.


title:
Influence of domain walls in the incommensurate charge density wave
  state of Cu intercalated 1$T$-TiSe$_2$

abstract:
  We report a low-temperature scanning tunneling microscopy study of the charge
density wave (CDW) order in 1$T$-TiSe$_2$ and Cu$_{0.08}$TiSe$_2$. In pristine
1$T$-TiSe$_2$ we observe a long-range coherent commensurate CDW (C-CDW) order.
In contrast, Cu$_{0.08}$TiSe$_{2}$ displays an incommensurate CDW (I-CDW) phase
with localized C-CDW domains separated by domain walls. Density of states
measurements indicate that the domain walls host an extra population of
fermions near the Fermi level which may play a role in the emergence of
superconductivity in this system. Fourier transform scanning tunneling
spectroscopy studies suggest that the dominant mechanism for CDW formation in
the I-CDW phase may be electron-phonon coupling.


title: Anomalous Feedback and Negative Domain Wall Resistance

abstract:
  Magnetic induction can be regarded as a negative feedback effect, where the
motive-force opposes the change of magnetic flux that generates the
motive-force. In artificial electromagnetics emerging from spintronics,
however, this is not necessarily the case. By studying the current-induced
domain wall dynamics in a cylindrical nanowire, we show that the spin
motive-force exerting on electrons can either oppose or support the applied
current that drives the domain wall. The switching into the anomalous feedback
regime occurs when the strength of the dissipative torque {\beta} is about
twice the value of the Gilbert damping constant {\alpha}. The anomalous
feedback manifests as a negative domain wall resistance, which has an analogy
with the water turbine.


title: Robust and efficient multi-way spectral clustering

abstract:
  We present a new algorithm for spectral clustering based on a column-pivoted
QR factorization that may be directly used for cluster assignment or to provide
an initial guess for k-means. Our algorithm is simple to implement, direct, and
requires no initial guess. Furthermore, it scales linearly in the number of
nodes of the graph and a randomized variant provides significant computational
gains. Provided the subspace spanned by the eigenvectors used for clustering
contains a basis that resembles the set of indicator vectors on the clusters,
we prove that both our deterministic and randomized algorithms recover a basis
close to the indicators in Frobenius norm. We also experimentally demonstrate
that the performance of our algorithm tracks recent information theoretic
bounds for exact recovery in the stochastic block model. Finally, we explore
the performance of our algorithm when applied to a real world graph.


title:
On the Optimality Equation for Average Cost Markov Decision Processes
  and its Validity for Inventory Control

abstract:
  As is well known, average-cost optimality inequalities imply the existence of
stationary optimal policies for Markov Decision Processes with average costs
per unit time, and these inequalities hold under broad natural conditions. This
paper provides sufficient conditions for the validity of the average-cost
optimality equation for an infinite state problem with weakly continuous
transition probabilities and with possibly unbounded one-step costs and
noncompact action sets. These conditions also imply the convergence of
sequences of discounted relative value functions to average-cost relative value
functions and the continuity of average-cost relative value functions. As shown
in the paper, the classic periodic-review inventory control problem satisfies
these conditions. Therefore, the optimality inequality holds in the form of an
equality with a continuous average-cost relative value function for this
problem. In addition, the $K$-convexity of discounted relative value functions
and their convergence to average-cost relative value functions, when the
discount factor increases to 1, imply the $K$-convexity of average-cost
relative value functions. This implies that average-cost optimal $(s,S)$
policies for the inventory control problem can be derived from the average-cost
optimality equation.


title: On the Group and Color Isomorphism Problems

abstract:
  In this paper, we prove results on the relationship between the complexity of
the group and color isomorphism problems. The difficulty of color isomorphism
problems is known to be closely linked to the the composition factors of the
permutation group involved. Previous works are primarily concerned with
applying color isomorphism to bou nded degree graph isomorphism, and have
therefore focused on the alternating composit ion factors, since those are the
bottleneck in the case of graph isomorphism.
  We consider the color isomorphism problem with composition factors restricted
to those other than the alternating group, show that group isomorphism reduces
in n^(O(log log n)) time to this problem, and, conversely, that a special case
of this color isomorphism problem reduces to a slight generalization of group
isomorphism. We then sharpen our results by identifying the projective special
linear group as the main obstacle to faster algorithms for group isomorphism
and prove that the aforementioned reduc tion from group isomorphism to color
isomorphism in fact produces only cyclic and projective special linear factors.
Our results demonstrate that, just as the alternatin g group was a barrier to
faster algorithms for graph isomorphism for three decades, the projective
special linear group is an obstacle to faster algorithms for group isomorphism.


title: Intrinsic localized mode and low thermal conductivity of PbSe

abstract:
  Lead chalcogenides such as PbS, PbSe, and PbTe are of interest for their
exceptional thermoelectric properties and strongly anharmonic lattice dynamics.
Although PbTe has received the most attention, PbSe has a lower thermal
conductivity despite being stiffer, a trend that prior first-principles
calculations have not reproduced. Here, we use ab-initio calculations that
explicitly account for strong anharmonicity to identify the origin of this low
thermal conductivity as an anomalously large anharmonic interaction, exceeding
in strength that in PbTe, between the transverse optic and longitudinal
acoustic branches. The strong anharmonicity is reflected in the striking
observation of an intrinsic localized mode that forms in the acoustic
frequencies. Our work shows the deep insights into thermal phonons that can be
obtained from ab-initio calculations that are not confined to the weak limit of
anharmonicity.


title: Constructing unlabelled lattices

abstract:
  We present an improved orderly algorithm for constructing all unlabelled
lattices up to a given size, that is, an algorithm that constructs the minimal
element of each isomorphism class relative to some total order.
  Our algorithm employs a stabiliser chain approach for cutting branches of the
search space that cannot contain a minimal lattice; to make this work, we grow
lattices by adding a new layer at a time, as opposed to adding one new element
at a time, and we use a total order that is compatible with this modified
strategy.
  The gain in speed is between one and two orders of magnitude. As an
application, we compute the number of unlabelled lattices on 20 elements.


title: Tidally-disrupted Molecular Clouds falling to the Galactic Center

abstract:
  We found a molecular cloud connecting from the outer region to the "Galactic
Center Mini-spiral (GCMS)" which is a bundle of the ionized gas streams
adjacent to Sgr A*. The molecular cloud has a filamentary appearance which is
prominent in the CS J=2-1 emission line and is continuously connected with the
GCMS. The velocity of the molecular cloud is also continuously connected with
that of the ionized gas in the GCMS observed in the H42alpha recombination
line. The morphological and kinematic relations suggest that the molecular
cloud is falling from the outer region to the vicinity of Sgr A*, being
disrupted by the tidal shear of Sgr A* and ionized by UV emission from the
Central Cluster. We also found the SiO J=2-1 emission in the boundary area
between the filamentary molecular cloud and the GCMS. There seems to exist
shocked gas in the boundary area.


title: Minimal charts of type (3,3)

abstract:
  Let $\Gamma$ be a chart. For each label $m$, we denote by $\Gamma_m$ the
"subgraph" of $\Gamma$ consisting of all the edges of label $m$ and their
vertices. Let $\Gamma$ be a minimal chart of type $(m;3,3)$. That is, a minimal
chart $\Gamma$ has six white vertices, and both of $\Gamma_m\cap\Gamma_{m+1}$
and $\Gamma_{m+1}\cap\Gamma_{m+2}$ consist of three white vertices. Then
$\Gamma$ is C-move equivalent to a minimal chart containing a "subchart"
representing a 2-twist spun trefoil or its "reflection".


title:
Dynamics of polar-core spin vortices in a ferromagnetic spin-1
  Bose-Einstein condensate

abstract:
  A ferromagnetic spin-1 condensate supports polar-core spin vortices (PCVs) in
the easy-plane phase. We derive a model for the dynamics of these PCVs using a
variational Lagrangian approach. The PCVs behave as massive charged particles
interacting under the two dimensional Coulomb interaction, with the mass
arising from interaction effects within the vortex core. We compare this model
to numerical simulations of the spin-1 Gross-Pitaevskii equations and find
semi-quantitative agreement. In addition, the numerical results suggest that
the PCV core couples to spin waves, and this affects the PCV dynamics even far
from the core. We identify areas of further research that could extend the
model of PCV dynamics presented here.


title: Quantum-Chemical Insights from Deep Tensor Neural Networks

abstract:
  Learning from data has led to paradigm shifts in a multitude of disciplines,
including web, text, and image search, speech recognition, as well as
bioinformatics. Can machine learning enable similar breakthroughs in
understanding quantum many-body systems? Here we develop an efficient deep
learning approach that enables spatially and chemically resolved insights into
quantum-mechanical observables of molecular systems. We unify concepts from
many-body Hamiltonians with purpose-designed deep tensor neural networks
(DTNN), which leads to size-extensive and uniformly accurate (1 kcal/mol)
predictions in compositional and configurational chemical space for molecules
of intermediate size. As an example of chemical relevance, the DTNN model
reveals a classification of aromatic rings with respect to their stability -- a
useful property that is not contained as such in the training dataset. Further
applications of DTNN for predicting atomic energies and local chemical
potentials in molecules, reliable isomer energies, and molecules with peculiar
electronic structure demonstrate the high potential of machine learning for
revealing novel insights into complex quantum-chemical systems.


title:
On the role of repetitive magnetic reconnections in evolution of
  magnetic flux-ropes in solar corona

abstract:
  Parker's magnetostatic theorem extended to astrophysical magnetofluids with
large magnetic Reynolds number supports ceaseless regeneration of current
sheets and hence, spontaneous magnetic reconnections recurring in time.
Consequently, a scenario is possible where the repeated reconnections provide
an autonomous mechanism governing emergence of coherent structures in
astrophysical magnetofluids. In this work, such a scenario is explored by
performing numerical computations commensurate with the magnetostatic theorem.
In particular, the computations explore the evolution of a flux-rope governed
by repeated reconnections in a magnetic geometry resembling bipolar loops of
solar corona. The revealed morphology of the evolution process, including onset
and ascent of the rope, reconnection locations and the associated topology of
the magnetic field lines, agrees with observations, and thus substantiates
physical realisability of the advocated mechanism.


title:
Global well-posedness of 2D nonlinear Boussinesq equations with mixed
  partial viscosity and thermal diffusivity

abstract:
  In this paper, we discuss with the global well-posedness of 2D anisotropic
nonlinear Boussinesq equations with any two positive viscosities and one
positive thermal diffusivity. More precisely, for three kinds of viscous
combinations, we obtain the global well-posedness without any assumption on the
solution. For other three difficult cases, under the minimal regularity
assumption, we also derive the unique global solution. To the authors'
knowledge, our result is new even for the simplified model.


title:
Distributed Regularized Primal-Dual Method: Convergence Analysis and
  Trade-offs

abstract:
  We study deterministic and stochastic primal-dual sub-gradient algorithms for
distributed optimization of a separable objective function with global
inequality constraints. In both algorithms, the norm of the Lagrangian
multipliers are controlled by augmenting the corresponding Lagrangian function
with a quadratic regularization term. Specifically, we show that when the
stepsize of each algorithm satisfies a certain restriction, the norm of the
Lagrangian multipliers is upper bounded by an expression that is inversely
proportional to the parameter of the regularization. We use this result to
compute upper bounds on the sub-gradients of the Lagrangian function. For the
deterministic algorithm, we prove a convergence rate for attaining the optimal
objective value. In the stochastic optimization case, we similarly prove
convergence rates both in the expectation and with a high probability, using
the method of bounded martingale difference. For both algorithms, we
demonstrate a trade-off between the convergence rate and the decay rate of the
constraint violation, in the sense that improving the convergence rate slows
the decay rate of the constraint violation and vice versa. We demonstrate the
convergence of our proposed algorithms numerically for distributed regression
with the hinge and logistic loss functions over different graph structures.


title:
The strong Morita equivalence for inclusions of $C^*$-algebras and
  conditional expectations for equivalence bimodules

abstract:
  We shall introduce the notions of the strong Morita equivalence for unital
inclusions of unital $C^*$-algebras and conditional expectations from an
equivalence bimodule onto its closed subspace with respect to conditional
expectations from unital $C^*$-algebras onto their unital $C^*$-subalgebras.
Also, we shall study their basic properties.


title: Top-N Recommendation on Graphs

abstract:
  Recommender systems play an increasingly important role in online
applications to help users find what they need or prefer. Collaborative
filtering algorithms that generate predictions by analyzing the user-item
rating matrix perform poorly when the matrix is sparse. To alleviate this
problem, this paper proposes a simple recommendation algorithm that fully
exploits the similarity information among users and items and intrinsic
structural information of the user-item matrix. The proposed method constructs
a new representation which preserves affinity and structure information in the
user-item rating matrix and then performs recommendation task. To capture
proximity information about users and items, two graphs are constructed.
Manifold learning idea is used to constrain the new representation to be smooth
on these graphs, so as to enforce users and item proximities. Our model is
formulated as a convex optimization problem, for which we need to solve the
well-known Sylvester equation only. We carry out extensive empirical
evaluations on six benchmark datasets to show the effectiveness of this
approach.


title: Minimum Distance and the Minimum Weight Codewords of Schubert Codes

abstract:
  We consider linear codes associated to Schubert varieties in Grassmannians. A
formula for the minimum distance of these codes was conjectured in 2000 and
after having been established in various special cases, it was proved in 2008
by Xiang. We give an alternative proof of this formula. Further, we propose a
characterization of the minimum weight codewords of Schubert codes by
introducing the notion of Schubert decomposable elements of certain exterior
powers. It is shown that codewords corresponding to Schubert decomposable
elements are of minimum weight and also that the converse is true in many
cases. A lower bound, and in some cases, an exact formula, for the number of
minimum weight codewords of Schubert codes is also given. From a geometric
point of view, these results correspond to determining the maximum number of
$\mathbb{F}_q$-rational points that can lie on a hyperplane section of a
Schubert variety in a Grassmannian with its nondegenerate embedding in a
projective subspace of the Pl\"ucker projective space, and also the number of
hyperplanes for which the maximum is attained.


title:
Mining Statistically Significant Attribute Associations in Attributed
  Graphs

abstract:
  Recently, graphs have been widely used to represent many different kinds of
real world data or observations such as social networks, protein-protein
networks, road networks, and so on. In many cases, each node in a graph is
associated with a set of its attributes and it is critical to not only consider
the link structure of a graph but also use the attribute information to achieve
more meaningful results in various graph mining tasks. Most previous works with
attributed graphs take into ac- count attribute relationships only between
individually connected nodes. However, it should be greatly valuable to find
out which sets of attributes are associated with each other and whether they
are statistically significant or not. Mining such significant associations, we
can uncover novel relationships among the sets of attributes in the graph. We
propose an algorithm that can find those attribute associations efficiently and
effectively, and show experimental results that confirm the high applicability
of the proposed algorithm.


title:
De-noising, Stabilizing and Completing 3D Reconstructions On-the-go
  using Plane Priors

abstract:
  Creating 3D maps on robots and other mobile devices has become a reality in
recent years. Online 3D reconstruction enables many exciting applications in
robotics and AR/VR gaming. However, the reconstructions are noisy and generally
incomplete. Moreover, during onine reconstruction, the surface changes with
every newly integrated depth image which poses a significant challenge for
physics engines and path planning algorithms. This paper presents a novel, fast
and robust method for obtaining and using information about planar surfaces,
such as walls, floors, and ceilings as a stage in 3D reconstruction based on
Signed Distance Fields. Our algorithm recovers clean and accurate surfaces,
reduces the movement of individual mesh vertices caused by noise during online
reconstruction and fills in the occluded and unobserved regions. We implemented
and evaluated two different strategies to generate plane candidates and two
strategies for merging them. Our implementation is optimized to run in
real-time on mobile devices such as the Tango tablet. In an extensive set of
experiments, we validated that our approach works well in a large number of
natural environments despite the presence of significant amount of occlusion,
clutter and noise, which occur frequently. We further show that plane fitting
enables in many cases a meaningful semantic segmentation of real-world scenes.


title:
Deriving analytic solutions for compact binary inspirals without
  recourse to adiabatic approximations

abstract:
  We utilize the dynamical renormalization group formalism to calculate the
real space trajectory of a compact binary inspiral for long times via a
systematic resummation of secularly growing terms. This method generates closed
form solutions without orbit averaging, and the accuracy can be systematically
improved. The expansion parameter is $v^5 \nu \Omega(t-t_0)$ where $t_0$ is the
initial time, $t$ is the time elapsed, and $\Omega$ and $v$ are the angular
orbital frequency and initial speed, respectively, and $\nu$ is the binary's
symmetric mass ratio. We demonstrate how to apply the renormalization group
method to resum solutions beyond leading order in two ways. First, we calculate
the second order corrections of the leading radiation reaction force, which
involves highly non-trivial checks of the formalism (i.e. its
renormalizability). Second, we show how to systematically include
post-Newtonian corrections to the radiation reaction force. By avoiding orbit
averaging we gain predictive power and eliminate ambiguities in the initial
conditions. Finally, we discuss how this methodology can be used to find
analytic solutions to the spin equations of motion that are valid over long
times.


title: Spectral Bounds for the Ising Ferromagnet on an Arbitrary Given Graph

abstract:
  We revisit classical bounds of M. E. Fisher on the ferromagnetic Ising model,
and show how to efficiently use them on an arbitrary given graph to rigorously
upper-bound the partition function, magnetizations, and correlations. The
results are valid on any finite graph, with arbitrary topology and arbitrary
positive couplings and fields. Our results are based on high temperature
expansions of the aforementioned quantities, and are expressed in terms of two
related linear operators: the non-backtracking operator and the Bethe Hessian.
As a by-product, we show that in a well-defined high-temperature region, the
susceptibility propagation algorithm converges and provides an upper bound on
the true spin-spin correlations.


title:
Efficient Coded Cooperative Networks with Energy Harvesting and Wireless
  Power Transfer

abstract:
  The optimum off-line energy management scheme for multi-user multi-relay
networks employing energy harvesting and wireless energy transfer is studied.
Specifically, the users are capable of harvesting and transferring energy to
each other over consecutive transmissions, though they have no fixed energy
supplies. Meanwhile, network coding for the users' messages is conducted at the
relays to enable cooperative transmission with source nodes in independent but
not necessarily identically distributed (i.n.i.d.) Nakagami-$m$ fading
channels. Therefore, a simultaneous two level cooperation, i.e.,
information-level and energy-level cooperation is conducted. The problem of
energy efficiency (EE) maximization under constraints of the energy causality
and a predefined outage probability threshold is formulated and shown to be
non-convex. By exploiting fractional and geometric programming, a convex
form-based iterative algorithm is developed to solve the problem efficiently.
Close-to-optimal power allocation and energy cooperation policies across
consecutive transmissions are found. Moreover, the effects of relay locations
and wireless energy transmission efficiency are investigated and the
performance comparison with the current state of solutions demonstrates that
the proposed policies can manage the harvested energy more efficiently.


title:
A generalized two-component model of solar wind turbulence and ab initio
  diffusion mean free paths and drift lengthscales of cosmic rays

abstract:
  We extend a two-component model for the evolution of fluctuations in the
solar wind plasma so that it is fully three-dimensional (3D) and also coupled
self-consistently to the large-scale magnetohydrodynamic (MHD) equations
describing the background solar wind. The two classes of fluctuations
considered are a high-frequency parallel-propagating wave-like piece and a
low-frequency quasi-two-dimensional component. For both components, the
nonlinear dynamics is dominanted by quasi-perpendicular spectral cascades of
energy. Driving of the fluctuations, by, for example, velocity shear and pickup
ions, is included. Numerical solutions to the new model are obtained using the
Cronos framework, and validated against previous simpler models. Comparing
results from the new model with spacecraft measurements, we find improved
agreement relative to earlier models that employ prescribed background solar
wind fields. Finally, the new results for the wave-like and
quasi-two-dimensional fluctuations are used to calculate ab initio diffusion
mean free paths and drift lengthscales for the transport of cosmic rays in the
turbulent solar wind.


title: Structural characterization of Cayley graphs

abstract:
  We show that the directed labelled Cayley graphs coincide with the rooted
deterministic vertex-transitive simple graphs. The Cayley graphs are also the
strongly connected deterministic simple graphs of which all vertices have the
same cycle language, or just the same elementary cycle language. Under the
assumption of the axiom of choice, we characterize the Cayley graphs for all
group subsets as the deterministic, co-deterministic, vertex-transitive simple
graphs.


title: Lifting laws and arithmetic invariant theory

abstract:
  In this paper we discuss lifting laws which, roughly, are ways of "lifting"
elements of the open orbit of one prehomogeneous vector space to elements of
the minimal nonzero orbit of another prehomogeneous vector space. We prove a
handful of these lifting laws, and show how they can be used to help solve
certain problems in arithmetic invariant theory. Of the results contained in
this article are twisted versions of certain parametrization theorems of
Bhargava.


title: To Infinity and Beyond: Some ODE and PDE Case Studies

abstract:
  When mathematical/computational problems reach infinity, extending analysis
and/or numerical computation beyond it becomes a notorious challenge. We
suggest that, upon suitable singular transformations (that can in principle be
computationally detected on the fly) it becomes possible to go beyond infinity
to the other side, with the solution becoming again well behaved and the
computations continuing normally. In our lumped, Ordinary Differential Equation
(ODE) examples this infinity crossing can happen instantaneously; at the
spatially distributed, Partial Differential Equation (PDE) level the crossing
of infinity may even persist for finite time, necessitating the introduction of
conceptual (and computational) buffer zones in which an appropriate singular
transformation is continuously (locally) detected and performed. These
observations (and associated tools) could set the stage for a systematic
approach to bypassing infinity (and thus going beyond it) in a broader range of
evolution equations; they also hold the promise of meaningfully and seamlessly
performing the relevant computations. Along the path of our analysis, we
present a regularization process via complexification and explore its impact on
the dynamics; we also discuss a set of compactification transformations and
their intuitive implications.


title: Composite Functional Metasurfaces for Multispectral Achromatic Optics

abstract:
  Nanostructured metasurfaces offer unique capabilities for local control of
the phase and amplitude of transmitted and reflected optical waves. Based on
this potential, a large number of metasurfaces have been proposed in recent
years as alternatives to standard optical elements. In most cases, however,
these elements suffer from large chromatic aberrations, thus limiting their
usefulness for multi-wavelength or broadband applications. Here, in order to
alleviate and correct the chromatic aberrations of individual diffractive
elements, we introduce dense vertical stacking of independent metasurfaces,
where each layer comprises a different material, and is optimally designed for
a different band within the visible spectrum. Using this approach, we
demonstrate the first triply RGB achromatic metalens in the visible range and
perform color imaging with this lens. We further demonstrate functional beam
shaping by constructing a self-aligned integrated element for Stimulated
Emission Depletion (STED) microscopy and a lens that provides anomalous
dispersive focusing. These demonstrations lead the way to the realization of
superachromatic ultrathin optical elements and multiple functional operations,
all in in a single nanostructured ultrathin element.


title:
Computer Folding of RNA Tetraloops: Identification of Key Force Field
  Deficiencies

abstract:
  The computer-aided folding of biomolecules, particularly RNAs, is one of the
most difficult challenges in computational structural biology. RNA tetraloops
are fundamental RNA motifs playing key roles in RNA folding and RNA-RNA and
RNA-protein interactions. Although state-of-the-art Molecular Dynamics (MD)
force fields correctly describe the native state of these tetraloops as a
stable free-energy basin on the microsecond time scale, enhanced sampling
techniques reveal that the native state is not the global free energy minimum,
suggesting yet unidentified significant imbalances in the force fields. Here,
we tested our ability to fold the RNA tetraloops in various force fields and
simulation settings. We employed three different enhanced sampling techniques,
namely, temperature replica exchange MD (T-REMD), replica exchange with solute
tempering (REST2), and well-tempered metadynamics (WT-MetaD). We aimed to
separate problems caused by limited sampling from those due to force-field
inaccuracies. We found that none of the contemporary force fields is able to
correctly describe folding of the 5'-GAGA-3' tetraloop over a range of
simulation conditions. We thus aimed to identify which terms of the force field
are responsible for this poor description of TL folding. We showed that at
least two different imbalances contribute to this behavior, namely,
overstabilization of base-phosphate and/or sugar-phosphate interactions and
underestimated stability of the hydrogen bonding interaction in base pairing.
The first artifact stabilizes the unfolded ensemble, while the second one
destabilizes the folded state. The former problem might be partially alleviated
by reparametrization of the van der Waals parameters of the phosphate oxygens
suggested by Case et al., while in order to overcome the latter effect we
suggest local potentials to better capture hydrogen bonding interactions.

categories: q-bio.BM physics.bio-ph physics.chem-ph physics.comp-ph


title: Overdamped stochastic thermodynamics with multiple reservoirs

abstract:
  After establishing stochastic thermodynamics for underdamped Langevin systems
in contact with multiple reservoirs, we derive its overdamped limit using
timescale separation techniques. The overdamped theory is different from the
naive theory that one obtains when starting from overdamped Langevin or
Fokker-Planck dynamics and only coincide with it in presence of a single
reservoir. The reason is that the coarse-grained fast momenta dynamics reaches
a nonequilibrium state which conducts heat in presence of multiple reservoirs.
The underdamped and overdamped theory are both shown to satisfy fundamental
fluctuation theorems. Their predictions for the heat statistics are derived
analytically for a Brownian particle on a ring in contact with two reservoirs
and subjected to a non-conservative force and are shown to coincide in the
long-time limit.


title: On the cohomology of $GL_3$ of elliptic curves and Quillen's conjecture

abstract:
  The paper provides a computation of the additive structure as well as a
partial description of the Chern-class module structure of the cohomology of
$GL_3$ over the function ring of an elliptic curve over a finite field. The
computation is achieved by a detailed analysis of the isotropy spectral
sequence for the action of $GL_3$ on the associated Bruhat-Tits building. This
provides insights into the function field version of Quillen's conjecture on
the structure of cohomology rings of arithmetic groups. The computations
exhibit a lot of explicit classes which are torsion for the Chern-class ring.
In some examples, even the torsion-free quotient of cohomology fails to be
free. A possible variation of Quillen's conjecture is also discussed.


title: Nori motives of curves with modulus and Laumon 1-motives

abstract:
  Let $k$ be a number field. We describe the category of Laumon 1-isomotives
over $k$ as the universal category in the sense of Nori associated with a
quiver representation built out of smooth proper $k$-curves with two disjoint
effective divisors and a notion of $H^1_\dR$ for such "curves with modulus".
This result extends and relies on the theorem of J. Ayoub and L. Barbieri-Viale
that describes Deligne's category of 1-isomotives in terms of Nori's Abelian
category of motives.


title:
Measurement of Michel Parameters ($\bar\eta$, $\xi\kappa$) in the
  radiative leptonic decay of tau at Belle

abstract:
  We present the first measurement of the Michel parameters $\bar{\eta}$ and
$\xi\kappa$ in the radiative leptonic decay of the $\tau$ lepton using 703
f$\mathrm{b}^{-1}$ of data collected with the Belle detector at the KEKB
$e^+e^-$ collider. The Michel parameters are measured by an unbinned maximum
likelihood fit to the kinematic information of
$e^+e^-\rightarrow\tau^+\tau^-\rightarrow (\pi^+\pi^0
\bar{\nu})(l^-\nu\bar{\nu}\gamma)$ $(l=e$ or $\mu)$. The preliminary values of
the measured Michel parameters are $\bar{\eta} = -2.0 \pm 1.5 \pm 0.8$ and
$\xi\kappa = 0.6 \pm 0.4 \pm 0.2$, where the first error is statistical and the
second is systematic.


title: An Efficient Method for Robust Projection Matrix Design

abstract:
  Our objective is to efficiently design a robust projection matrix $\Phi$ for
the Compressive Sensing (CS) systems when applied to the signals that are not
exactly sparse. The optimal projection matrix is obtained by mainly minimizing
the average coherence of the equivalent dictionary. In order to drop the
requirement of the sparse representation error (SRE) for a set of training data
as in [15] [16], we introduce a novel penalty function independent of a
particular SRE matrix. Without requiring of training data, we can efficiently
design the robust projection matrix and apply it for most of CS systems, like a
CS system for image processing with a conventional wavelet dictionary in which
the SRE matrix is generally not available. Simulation results demonstrate the
efficiency and effectiveness of the proposed approach compared with the
state-of-the-art methods. In addition, we experimentally demonstrate with
natural images that under similar compression rate, a CS system with a learned
dictionary in high dimensions outperforms the one in low dimensions in terms of
reconstruction accuracy. This together with the fact that our proposed method
can efficiently work in high dimension suggests that a CS system can be
potentially implemented beyond the small patches in sparsity-based image
processing.


title: Equality of Dedekind sums modulo 24$\mathbb Z$

abstract:
  Let $S(a,b)=12s(a,b)$, where $s(a,b)$ denotes the classical Dedekind sum. In
a recent note E. Tsukerman gave a necessary and sufficient condition for
$S(a_1,b)-S(a_2,b)\in 8\mathbb Z$. In the present paper we show that this
condition is equivalent to $S(a_1,b)-S(a_2,b)\in 24\mathbb Z$, provided that
$9\nmid b$. Tsukerman also obtained a congruence mod 8 for $bT(a,b)$, where
$T(a,b)$ is the alternating sum of the partial quotients of the continued
fraction expansion of $a/b$. We show that the respective congruence holds mod
$24$ if $3\nmid b$ and mod $72$ if $3\mid b$.


title:
A data-driven model for influenza transmission incorporating media
  effects

abstract:
  Numerous studies have attempted to model the effect of mass media on the
transmission of diseases such as influenza, however quantitative data on media
engagement has until recently been difficult to obtain. With the recent
explosion of "big data" coming from online social media and the like, large
volumes of data on a population's engagement with mass media during an epidemic
are becoming available to researchers. In this study we combine an online data
set comprising millions of shared messages relating to influenza with
traditional surveillance data on flu activity to suggest a functional form for
the relationship between the two. Using this data we present a simple
deterministic model for influenza dynamics incorporating media effects, and
show that such a model helps explain the dynamics of historical influenza
outbreaks. Furthermore, through model selection we show that the proposed media
function fits historical data better than other media functions proposed in
earlier studies.


title:
A First-Principles Comparative Study of Lithium, Sodium, and Magnesium
  Storage in Pure and Gallium-Doped Germanium: Competition between Interstitial
  and Substitutional Sites

abstract:
  Thermodynamics and kinetics of Li, Na, and Mg storage in Ge is studied ab
initio. The most stable configurations can consist of tetrahedral,
substitutional, or a combination of the two types of sites. In the dilute
limit, Li, Na prefer interstitial, while Mg prefers substitutional sites. At
higher concentrations of Li, Na, and Mg, there is a combination of interstitial
and substitutional sites. This is an important finding, as previous ab initio
studies of alloying type electrode materials ignored substitutional sites.
Insertion energies computed at dilute concentration (x = 1/64) show that Na and
Mg insertion are not thermodynamically favored in Ge vs formation of bulk Na
and Mg, as opposed to Li insertion which is favored. We investigate the effect
of p-doping of Ge (with Ga) on the thermodynamics and find that it considerably
lowers the defect formation energies associated with the insertion of Li/Na/Mg
at tetrahedral sites. On the other hand, the energetics associated with
Li/Na/Mg insertion at substitutional sites are not significantly affected. In
addition, we compute the migration energy barriers for Li/Na/Mg diffusion
between two tetrahedral sites (0.38/0.79/0.66 eV), between two substitutional
sites (0.77/0.93/1.83 eV), and between two sites of different type
(2.15/1.75/0.85 eV).


title:
Is cancer a disease that can be cured? An answer based on a new
  classification of diseases

abstract:
  Is cancer a disease that can be cured or a degenerative disease which comes
predominantly with old age? We give an answer based on a two-dimensional
representation of diseases. These two dimensions are defined as follows. In
mortality curves there is an age, namely a_c = 10 years, which plays a crucial
role in the sense that the mortality rate decreases in the interval I1=(a<a_c)
and increases in the interval I2=(a>a_c). The respective trends in I1 and I2
are the two parameters used in our classification of diseases. Within the
framework of reliability analysis, I1 and I2 would be referred to as the
"burn-in" and "wear-out" phases. This leads to define three broad groups of
diseases. (AS1) Asymmetry with prevalence of I1. (AS2) Asymmetry with
prevalence of I2. (S) Symmetry, with I1 and I2 both playing roles of comparable
importance. Not surprisingly, among AS1-cases one finds all diseases due to
congenital malformations. In the AS2-class one finds degenerative diseases,
e.g. Alzheimer's disease. Among S-cases one finds most diseases due to external
pathogens or to wear-out processes. Cancer is one of those mixed cases and it
is closer to (AS2) than to (AS1). This representation also explains what we
call an OVERKILL EFFECT in old age. It tells us that even an effective cancer
therapy would have no influence whatsoever on the extent of human life unless
ALL other diseases are cured simultaneously. We conclude that whilst one might
develop a cure for many of the known diseases of old age, new diseases will
arise and the quest for the ultimate cure will be never ending. Death before
the age of 120 seems firmly written in our genetic code and the best we shall
be able to do is to help people cope with the inevitability of death as and
when it arises.


title: Online Unsupervised Multi-view Feature Selection

abstract:
  In the era of big data, it is becoming common to have data with multiple
modalities or coming from multiple sources, known as "multi-view data".
Multi-view data are usually unlabeled and come from high-dimensional spaces
(such as language vocabularies), unsupervised multi-view feature selection is
crucial to many applications. However, it is nontrivial due to the following
challenges. First, there are too many instances or the feature dimensionality
is too large. Thus, the data may not fit in memory. How to select useful
features with limited memory space? Second, how to select features from
streaming data and handles the concept drift? Third, how to leverage the
consistent and complementary information from different views to improve the
feature selection in the situation when the data are too big or come in as
streams? To the best of our knowledge, none of the previous works can solve all
the challenges simultaneously. In this paper, we propose an Online unsupervised
Multi-View Feature Selection, OMVFS, which deals with large-scale/streaming
multi-view data in an online fashion. OMVFS embeds unsupervised feature
selection into a clustering algorithm via NMF with sparse learning. It further
incorporates the graph regularization to preserve the local structure
information and help select discriminative features. Instead of storing all the
historical data, OMVFS processes the multi-view data chunk by chunk and
aggregates all the necessary information into several small matrices. By using
the buffering technique, the proposed OMVFS can reduce the computational and
storage cost while taking advantage of the structure information. Furthermore,
OMVFS can capture the concept drifts in the data streams. Extensive experiments
on four real-world datasets show the effectiveness and efficiency of the
proposed OMVFS method. More importantly, OMVFS is about 100 times faster than
the off-line methods.


title: Dynamical Observations of Self-Stabilising Stationary Light

abstract:
  Precise control of atom-light interactions is vital to many quantum
information protocols. In particular, atomic systems can be used to slow and
store light to form a quantum memory. Optical storage can be achieved via
stopped light, where no optical energy remains in the atoms, or as stationary
light, where some optical energy remains resent during storage. In this work,
we demonstrate a form of self-stabilising stationary light. From any initial
state, our atom-light system evolves to a stable configuration that is devoid
of coherent emission from the atoms, yet may contain bright optical excitation.
This phenomenon is verified experimentally in a cloud of cold Rb87 atoms. The
spinwave in our atomic cloud is imaged from the side allowing direct comparison
with theoretical predictions.


title: Note: A replica liquid theory of binary mixtures

abstract:
  It has been known that the binary replica liquid theory (RLT) is inconsistent
with its one-component counterpart; In the limit that all atoms are identical,
the configurational entropy and thus the glass transition point calculated by
the binary RLT differ from those obtained by the one-component RLT. More
specifically, an extra composition-dependent term, or the mixing entropy,
remains finite in the configurational entropy computed by the binary RLT. In
this Short Note, we reformulate the RLT in order to resolve this problem.


title: WR 148: Identifying the companion of an extreme runaway massive binary

abstract:
  WR 148 (HD 197406) is an extreme runaway system considered to be a potential
candidate for a short-period (4.3173 d) rare WR + compact object binary.
Provided with new high resolution, high signal-to-noise spectra from the Keck
observatory, we determine the orbital parameters for both the primary WR and
the secondary, yielding respective projected orbital velocity amplitudes of
$88.1\pm3.8$ km s$^{-1}$ and $79.2\pm3.1$ km s$^{-1}$ and implying a mass ratio
of $1.1\pm0.1$. We then apply the shift-and-add technique to disentangle the
spectra and obtain spectra compatible with a WN7ha and an O4-6 star.
Considering an orbital inclination of $\sim67^\circ$, derived from previous
polarimetry observations, the system's total mass would be a mere 2-3
M$_{\odot}$ , an unprecedented result for a putative massive binary system.
However, a system comprising a 37 M$_{\odot}$ secondary (typical mass of an O5V
star) and a 33 M$_{\odot}$ primary (given the mass ratio) would infer an
inclination of $\sim18^\circ$. We therefore reconsider the previous methods of
deriving the orbital inclination based on time-dependent polarimetry and
photometry. While the polarimetric results are inconclusive requiring better
data, the photometric results favour low inclinations. Finally, we compute WR
148's space velocity and retrace the runaway's trajectory back to the Galactic
plane (GP). With an ejection velocity of $198\pm27$ km s$^{-1}$ and a travel
time of $4.7\pm0.8$ Myr to reach its current location, WR 148 was most likely
ejected via dynamical interactions in a young cluster.


title: Central Engine of Late-Time X-ray Flares with Internal Origin

abstract:
  This work focuses on a sample of seven extremely late-time X-ray flares with
peak time $t_{\rm p} > 10^4 {\rm s}$, among which two flares can be confirmed
as the late-time activity of central engine. The main purpose is to investigate
the mechanism of such late-time flares based on the internal origin assumption.
In the hyper-accreting black hole (BH) scenario, we study the possibility of
two well-known mechanisms as the central engine to power such X-ray flares,
i.e., the neutrino-antineutrino annihilation and the Blandford-Znajek (BZ)
process. Our results show that the annihilation luminosity is far below the
observational data. Thus, the annihilation mechanism cannot account for such
late-time flares. For the BZ process, if the role of outflows is taken into
consideration, the inflow mass rate near the horizon will be quite low such
that the magnetic field will probably be too weak to power the observed X-ray
flares. We therefore argue that, for the late-time flares with internal origin,
the central engine is unlikely to be associated with BHs. On the contrary, a
fast rotating neutron star with strong bipolar magnetic fields may be
responsible for such flares.


title: Image Retrieval with Fisher Vectors of Binary Features

abstract:
  Recently, the Fisher vector representation of local features has attracted
much attention because of its effectiveness in both image classification and
image retrieval. Another trend in the area of image retrieval is the use of
binary features such as ORB, FREAK, and BRISK. Considering the significant
performance improvement for accuracy in both image classification and retrieval
by the Fisher vector of continuous feature descriptors, if the Fisher vector
were also to be applied to binary features, we would receive similar benefits
in binary feature based image retrieval and classification. In this paper, we
derive the closed-form approximation of the Fisher vector of binary features
modeled by the Bernoulli mixture model. We also propose accelerating the Fisher
vector by using the approximate value of posterior probability. Experiments
show that the Fisher vector representation significantly improves the accuracy
of image retrieval compared with a bag of binary words approach.


title: Spectral shift functions and Dirichlet-to-Neumann maps

abstract:
  The spectral shift function of a pair of self-adjoint operators is expressed
via an abstract operator valued Titchmarsh--Weyl $m$-function. This general
result is applied to different self-adjoint realizations of second-order
elliptic partial differential operators on smooth domains with compact
boundaries, Schr\"{o}dinger operators with compactly supported potentials, and
finally, Schr\"{o}dinger operators with singular potentials supported on
hypersurfaces. In these applications the spectral shift function is determined
in an explicit form with the help of (energy parameter dependent)
Dirichlet-to-Neumann maps.


title:
The Effects of Data Size and Frequency Range on Distributional Semantic
  Models

abstract:
  This paper investigates the effects of data size and frequency range on
distributional semantic models. We compare the performance of a number of
representative models for several test settings over data of varying sizes, and
over test items of various frequency. Our results show that neural
network-based models underperform when the data is small, and that the most
reliable model over data of varying sizes and frequency ranges is the inverted
factorized model.


title:
Energy gap in tunneling spectroscopy: effect of the chemical potential
  shift

abstract:
  We study the effect of a shift of the chemical potential level on the
tunneling conductance spectra. In the systems with gapped energy spectra,
significant chemical-potential dependent distortions of the differential
tunneling conductance curves, $dI/dV$, arise in the gap region. An expression
is derived for the correction of the $dI/dV$, which in a number of cases was
found to be large. The sign of the correction depends on the chemical potential
level position with respect to the gap. The correction of the $dI/dV$
associated with the chemical potential shift has a nearly linear dependence on
the tip-sample separation $z$ and vanishes at $z\to 0$.


title:
Propagation studies for the construction of atomic macro-coherence in
  dense media as a tool to investigate neutrino physics

abstract:
  In this manuscript we review the possibility of inducing large coherence in a
macroscopic dense target by using adiabatic techniques. For this purpose we
investigate the degradation of the laser pulse through propagation, which was
also related to the size of the prepared medium. Our results show that,
although adiabatic techniques offer the best alternative in terms of stability
against experimental parameters, for very dense media it is necessary to
engineer laser-matter interaction in order to minimize laser field degradation.
This work has been triggered by the proposal of a new technique, namely
Radiative Emission of Neutrino Pairs (RENP), capable of investigating neutrino
physics through quantum optics concepts which require the preparation of a
macrocoherent state.


title:
Truncated linear statistics associated with the top eigenvalues of
  random matrices

abstract:
  Given a certain invariant random matrix ensemble characterised by the joint
probability distribution of eigenvalues $P(\lambda_1,\ldots,\lambda_N)$, many
important questions have been related to the study of linear statistics of
eigenvalues $L=\sum_{i=1}^Nf(\lambda_i)$, where $f(\lambda)$ is a known
function. We study here truncated linear statistics where the sum is restricted
to the $N_1<N$ largest eigenvalues: $\tilde{L}=\sum_{i=1}^{N_1}f(\lambda_i)$.
Motivated by the analysis of the statistical physics of fluctuating
one-dimensional interfaces, we consider the case of the Laguerre ensemble of
random matrices with $f(\lambda)=\sqrt{\lambda}$. Using the Coulomb gas
technique, we study the $N\to\infty$ limit with $N_1/N$ fixed. We show that the
constraint that $\tilde{L}=\sum_{i=1}^{N_1}f(\lambda_i)$ is fixed drives an
infinite order phase transition in the underlying Coulomb gas. This transition
corresponds to a change in the density of the gas, from a density defined on
two disjoint intervals to a single interval. In this latter case the density
presents a logarithmic divergence inside the bulk. Assuming that $f(\lambda)$
is monotonous, we show that these features arise for any random matrix ensemble
and truncated linear statitics, which makes the scenario described here robust
and universal.


title: Deterministic extinction by mixing in cyclically competing species

abstract:
  We consider a cyclically competing species model on a ring with global mixing
at finite rate, which corresponds to the well-known Lotka-Volterra equation in
the limit of infinite mixing rate. Within a perturbation analysis of the model
from the infinite mixing rate, we provide analytical evidence that extinction
occurs deterministically at sufficiently large but finite values of the mixing
rate for any species number $N\ge3$. Further, by focusing on the cases of
rather small species numbers, we discuss numerical results concerning the
trajectories toward such deterministic extinction, including global
bifurcations caused by changing the mixing rate.


title: Accretion onto a Moving Reissner-Nordstr\"{o}m Black Hole

abstract:
  We obtain an analytic solution for accretion of a gaseous medium with a
adiabatic equation of state ($P=\rho$) onto a Reissner-Nordstr\"{o}m black hole
which moves at a constant velocity through the medium. We obtain the specific
expression for each component of the velocity and present the mass accretion
rate which depends on the mass and the electric charge. The result we obtained
may be helpful to understand the physical mechanism of accretion onto a moving
black hole.


title:
Parareal algorithms applied to stochastic differential equations with
  conserved quantities

abstract:
  In this papers, we couple the parareal algorithm with projection methods of
the trajectory on a specific manifold, defined by the preservation of some
conserved quantities of the differential equations. First, projection methods
are introduced as the coarse and fine propagators. Second, we also apply the
projection methods for systems with conserved quantities in the correction step
of original parareal algorithm. Finally, three numerical experiments are
performed by different kinds of algorithms to show the property of convergence
in iteration, and preservation in conserved quantities of model systems.


title:
Converse Bounds on Modulation-Estimation Performance for the Gaussian
  Multiple-Access Channel

abstract:
  This paper focuses on the problem of separately modulating and jointly
estimating two independent continuous-valued parameters sent over a Gaussian
multiple-access channel (MAC) under the mean square error (MSE) criterion. To
this end, we first improve an existing lower bound on the MSE that is obtained
using the parameter modulation-estimation techniques for the single-user
additive white Gaussian noise (AWGN) channel. As for the main contribution of
this work, this improved modulation-estimation analysis is generalized to the
model of the two-user Gaussian MAC, which will likely become an important
mathematical framework for the analysis of remote sensing problems in wireless
networks. We present outer bounds to the achievable region in the plane of the
MSEs of the two user parameters, which provides a trade-off between the MSEs,
in addition to the upper bounds on the achievable region of the MSE exponents,
namely, the exponential decay rates of these MSEs in the asymptotic regime of
long blocks.


title:
Fabrication and Transport Properties of 100 m Class Sr0.6K0.4Fe2As2
  Wires and Pancake Coils

abstract:
  Iron-pnictides are hotly studied since 2008 in the superconducting materials
research area, due to their special properties and unclear mechanism. Big
achievement has been made in the pnictide research during the past years. For
practical uses, pnictide superconductor should be fabricated in a long wire
form which can be used for different devices. In this work, 100 m class 7-core
Sr0.6K0.4Fe2As2 (Sr122) tapes have been made using the powder-in-tube
technique, which is reported for the first time. Clearly, an average Jc of
1.3x10^4 A/cm^2 at 10 T was reached over the 115 meter length, showing a high
property and good uniformity of 100 meter level Sr122 tapes. Using the 10 m
long Sr122 tapes, two double-pancake coils were fabricated by a wind and
reaction technique. No transport current could be measured for the coil made
from the mono-filamentary tape. However, transport Ic was obtained in the coil
made from the 7-filamentary tape. The factors which affect the superconducting
property of the coil were discussed in this work.


title:
An Explicit Formula of the Intrinsic Metric on the Sierpinski Gasket via
  Code Representation

abstract:
  The computation of the distance between any two points of the Sierpinski
Gasket with respect to the intrinsic metric has already been investigated by
several authors. In the literature there is not an explicit formula using the
code space of the Sierpinski Gasket. In this paper, we give an explicit formula
for the intrinsic metric on the Sierpinski Gasket via code representations of
its points.


title: Involutive Heegaard Floer homology and rational cuspidal curves

abstract:
  We use invariants of Hendricks and Manolescu coming from involutive Heegaard
Floer theory to find constraints on possible configurations of singular points
of a rational cuspidal curve of odd degree in the projective plane. We show
that the results do not carry over to rational cuspidal curves of even degree.


title: An order theoretic characterization of spin factors

abstract:
  The famous Koecher-Vinberg theorem characterizes the Euclidean Jordan
algebras among the finite dimensional order unit spaces as the ones that have a
symmetric cone. Recently Walsh gave an alternative characterization of the
Euclidean Jordan algebras. He showed that the Euclidean Jordan algebras
correspond to the finite dimensional order unit spaces $(V,C,u)$ for which
there exists a bijective map $g\colon C^\circ\to C^\circ$ with the property
that $g$ is antihomogeneous, i.e., $g(\lambda x) =\lambda^{-1}g(x)$ for all
$\lambda>0$ and $x\in C^\circ$, and $g$ is an order-antimorphism, i.e.,
$x\leq_C y$ if and only if $g(y)\leq_C g(x)$. In this paper we make a first
step towards extending this order theoretic characterization to infinite
dimensional JB-algebras. We show that if $(V,C,u)$ is a complete order unit
space with a strictly convex cone and $\dim V\geq 3$, then there exists a
bijective antihomogeneous order-antimorphism $g\colon C^\circ\to C^\circ$ if
and only if $(V,C,u)$ is a spin factor.


title:
Dispersive interaction of a Bose-Einstein condensate with the movable
  mirror of an optomechanical cavity in the presence of the laser phase noise

abstract:
  We theoretically investigate the dispersive interaction of a Bose-Einstein
condensate (BEC) trapped inside an optomechanical cavity with a moving end
mirror in the presence of the laser phase noise (LPN) as well as the atomic
collisions. We assume that the effective frequency of the optical mode is much
greater than those of the mechanical and the Bogoliubov modes of the movable
mirror and the BEC . In the adiabatic approximation where the damping rate of
the cavity is faster than those of the other modes, the system behaves as an
effective two-mode model in which the atomic and mechanical modes are coupled
to each other through the mediation of the optical field by an effective
coupling parameter. We show that in the effective two-mode model, the LPN
appears as a classical stochastic pump term which drives the amplitude
quadratures of the mechanical and the Bogoliubov modes. It is also shown that a
strong stationary mirror-atom entanglement can be established just in the
dispersive and Doppler regimes where the two modes come into resonance with
each other and the effect of the LPN gets very low.


title: Mechanics of Apparent Horizon in Two Dimensional Dilaton Gravity

abstract:
  In this article, we give a definition of apparent horizon in a two
dimensional general dilaton gravity theory. With this definition, we construct
the mechanics of the apparent horizon by introducing a quasi-local energy of
the theory. Our discussion generalizes the apparent horizons mechanics in
general spherically symmetric spactimes in four or higher dimensions to the two
dimensional dilaton gravity case.


title:
A dislocation-based explanation of quasi-elastic release in shock-loaded
  aluminum

abstract:
  A novel explanation of the quasielastic release phenomenon in shock
compressed aluminum is presented. A dislocation-based model, taking into
account dislocation substructures and evolution, is applied to simulate the
elastic plastic response of both single crystal and poly crystalline aluminum.
The calculated results are in good agreement with experimental results from not
only the velocity profiles but also the shear strength and dislocation density,
which demonstrates the accuracy of our simulations. Simulated results indicate
that dislocation immobilization during dynamic deformation results in a smooth
increase of yield stress, which leads to the quasi-elastic release, while the
generation of dislocations caused by the plastic release wave results in the
appearance of a transition point between the quasielastic release and the
plastic release in the profile.


title:
On Units in Orders in 2-by-2 Matrices over Quaternion Algebras with
  Rational Center

abstract:
  We generalize an algorithm established in earlier work \cite{algebrapaper} to
compute finitely many generators for a subgroup of finite index of an
arithmetic group acting properly discontinuously on hyperbolic space of
dimension $2$ and $3$, to hyperbolic space of higher dimensions using Clifford
algebras.
  We hence get an algorithm which gives a finite set of generators of finite
index subgroups of a discrete subgroup of Vahlen's group, i.e. a group of
$2$-by-$2$ matrices with entries in the Clifford algebra satisfying certain
conditions.
  The motivation comes from units in integral group rings and this new
algorithm allows to handle unit groups of orders in $2$-by-$2$ matrices over
rational quaternion algebras. The rings investigated are part of the so-called
exceptional components of a rational group algebra.


title:
Heavy-flavour production in pp collisions and correlations in pp and
  p-Pb collisions measured with ALICE at the LHC

abstract:
  Thanks to its excellent tracking and particle identification performance, the
ALICE detector is capable of measuring D mesons at central rapidity via their
hadronic decay channels down to very low transverse momentum. We show an
extension of the prompt ${\rm D}^0$ $p_{\rm T}$-differential cross section
measurement down to zero transverse momentum, which allows us to determine the
$p_{\rm T}$-integrated charm production cross section at central rapidity in pp
collisions at $\sqrt{s}$ = 7 TeV. We also present measurements of azimuthal
correlations of prompt ${\rm D}^0$, ${\rm D}^+$ and ${\rm D}^{*+}$ mesons with
charged hadrons in pp collisions at $\sqrt{s}$ = 7 TeV and p-Pb collisions at
$\sqrt{s_{\scriptscriptstyle \rm NN}}$ = 5.02 TeV and compare the results with
expectations from models.


title:
The accuracy of biochemical interactions is ensured by endothermic
  stepwise kinetics

abstract:
  The discerning behavior of living systems relies on accurate interactions
selected from the lot of molecular collisions occurring in the cell. To ensure
the reliability of interactions, binding partners are classically envisioned as
finely preadapted molecules, evolutionarily selected on the basis of their
affinity in one-step associations. But the counterselection of inappropriate
interactions can in fact be much more efficiently obtained through difficult
multi-step adjustment, whose final high energy state is locked by a fluctuation
ratchet. The progressive addition of molecular bonds during stereo-adjustment
can be modeled as a predominantly backward random walk whose first arrival is
frozen by a micro-irreversible transition. A new criterion of ligand
specificity is presented, that is based on the ratio rejection/incorporation.
In addition to its role in the selectivity of interactions, this generic recipe
can underlie other important biological phenomena such as the regular synthesis
at low level of supramolecular complexes, monostable kinetic bimodality,
substrate concentration thresholds or the preparation of rapidly
depolymerizable structureswith stored energy, like microtubules.


title: A new proof of the Nonsolvable Signalizer Functor Theorem

abstract:
  The Signalizer Functor Method as developed by Gorenstein and Walter played a
fundamental role in the first proof of the Classification of the Finite Simple
Groups. It plays a similar role in the new proof of the Classification in the
Gorenstein-Lyons-Solomon book series. The key results are Glauberman's Solvable
Signalizer Functor Theorem and McBride's Nonsolvable Signalizer Functor
Theorem. Given their fundamental role, it is desirable to have new and
different proofs of them. This is accomplished in {\em A new proof of the
Solvable Signalizer Functor Theorem,} P. Flavell, J. Algebra, 398 (2014)
350--363 for Glauberman's Theorem. The purpose of this paper is to give a new
proof of McBride's Theorem.


title: Duality between Feature Selection and Data Clustering

abstract:
  The feature-selection problem is formulated from an information-theoretic
perspective. We show that the problem can be efficiently solved by an extension
of the recently proposed info-clustering paradigm. This reveals the fundamental
duality between feature selection and data clustering,which is a consequence of
the more general duality between the principal partition and the principal
lattice of partitions in combinatorial optimization.


title: Unsupervised Co-segmentation of 3D Shapes via Functional Maps

abstract:
  We present an unsupervised method for co-segmentation of a set of 3D shapes
from the same class with the aim of segmenting the input shapes into consistent
semantic parts and establishing their correspondence across the set. Starting
from meaningful pre-segmentation of all given shapes individually, we construct
the correspondence between same candidate parts and obtain the labels via
functional maps. And then, we use these labels to mark the input shapes and
obtain results of co-segmentation. The core of our algorithm is to seek for an
optimal correspondence between semantically similar parts through functional
maps and mark such shape parts. Experimental results on the benchmark datasets
show the efficiency of this method and comparable accuracy to the
state-of-the-art algorithms.


title:
Excitation injector in an atomic chain: long-ranged transport and
  efficiency amplification

abstract:
  We investigate the transport of energy in a linear chain of two-level quantum
emitters ("atoms") weakly coupled to a blackbody radiation bath. We show that,
simply by displacing one or more atoms from their regular-chain positions, the
efficiency of the energy transport can be considerably amplified of at least
one order of magnitude. Besides, in configurations providing an efficiency
greater than $100\%$ , the distance between the two last atoms of the chain can
be up to 20 times larger than the one in the regular chain, thus achieving a
much longer-range energy transport. By performing both a stationary and
time-dependent analysis, we ascribe this effect to an elementary block of three
atoms, playing the role of excitation injector from the blackbody bath to the
extraction site. By considering chains with up to 7 atoms, we also show that
the amplification is robust and can be further enhanced up to $1400\%$.


title:
The adjoint neutron transport equation and the statistical approach for
  its solution

abstract:
  The adjoint equation was introduced in the early days of neutron transport
and its solution, the neutron importance, has ben used for several applications
in neutronics. The work presents at first a critical review of the adjoint
neutron transport equation. Afterwards, the adjont model is constructed for a
reference physical situation, for which an analytical approach is viable, i.e.
an infinite homogeneous scattering medium. This problem leads to an equation
that is the adjoint of the slowing-down equation that is well-known in nuclear
reactor physics. A general closed-form analytical solution to such adjoint
equation is obtained by a procedure that can be used also to derive the
classical Placzek functions. This solution constitutes a benchmark for any
statistical or numerical approach to the adjoint equation. A sampling technique
to evaluate the adjoint flux for the transport equation is then proposed and
physically interpreted as a transport model for pseudo-particles. This can be
done by introducing appropriate kernels describing the transfer of the
pseudo-particles in phase space. This technique allows estimating the
importance function by a standard Monte Carlo approach. The sampling scheme is
validated by comparison with the analytical results previously obtained.


title: Proximity-induced Shiba states in a molecular junction

abstract:
  Superconductors containing magnetic impurities exhibit intriguing phenomena
derived from the competition between Cooper pairing and Kondo screening. At the
heart of this competition are the Yu-Shiba-Rusinov (Shiba) states which arise
from the pair breaking effects a magnetic impurity has on a superconducting
host. Hybrid superconductor-molecular junctions offer unique access to these
states but the added complexity in fabricating such devices has kept their
exploration to a minimum. Here, we report on the successful integration of a
model spin 1/2 impurity, in the form of a neutral and stable all organic
radical molecule, in proximity-induced superconducting break-junctions. Our
measurements reveal excitations which are characteristic of a spin-induced
Shiba state due to the radical's unpaired spin strongly coupled to a
superconductor. By virtue of a variable molecule-electrode coupling, we access
both the singlet and doublet ground states of the hybrid system which give rise
to the doublet and singlet Shiba excited states, respectively. Our results show
that Shiba states are a robust feature of the interaction between a
paramagnetic impurity and a proximity-induced superconductor where the excited
state is mediated by correlated electron-hole (Andreev) pairs instead of Cooper
pairs.


title: A Heat Flow for Diffeomorphisms of Flat Tori

abstract:
  In this paper we study the parabolic evolution equation $\partial_t
u=(|Du|^{2}+2|\det Du|)^{-1} \Delta u$, where $u : M\times[0,\infty) \to N$ is
an evolving map between compact flat surfaces. We use a tensor maximum
principle for the induced metric to establish two-sided bounds on the singular
values of Du, which shows that unlike harmonic map heat flow, this flow
preserves diffeomorphisms. A change of variables for Du then allows us to
establish a $C^\alpha$ estimate for the coefficient of the tension field, and
thus (thanks to the quasilinear structure and the Schauder estimates) we get
full regularity and long-time existence. We conclude with some energy estimates
to show convergence to an affine diffeomorphism.


title:
Conformational selection or induced fit? New insights from old
  principles

abstract:
  A long standing debate in biochemistry is to determine whether the
conformational changes observed during biomolecular interactions proceed
through conformational selection (of preexisting isoforms) or induced fit
(ligand-induced 3D reshaping). The latter mechanism had been invoked in certain
circumstances, for example to explain the non-Michaelian activity of monomeric
enzymes like glucokinase. But the relative importance of induced fit has been
recently depreciated in favor of conformational selection, assumed to be always
sufficient, predominant in general and in particular for glucokinase. The
relative contributions of conformational selection and induced fit are
reconsidered here in and out of equilibrium, in the light of earlier concepts
such as the cyclic equilibrium rule and the turning wheel of Wyman, using
single molecule state probability, one way fluxes and net fluxes. The
conditions for a switch from conformational selection to induced fit at a given
ligand concentration are explicitly determined. Out of equilibrium, the
inspection of the enzyme states circuit shows that conformational selection
alone would give a Michaelian reaction rate but not the established nonlinear
behaviour of glucokinase. Moreover, when induced fit and conformational
selection coexist and allow kinetic cooperativity, the net flux emerging in the
linkage cycle necessarily corresponds to the induced fit path.


title:
The Impact of Bulges on the Radial Distribution of Supernovae in Disc
  Galaxies

abstract:
  We present the results of the analysis of the impact of bulges on the radial
distributions of the different types of supernovae (SNe) in the stellar discs
of host galaxies with various morphologies. We find that in Sa-Sm galaxies, all
core-collapse (CC) and vast majority of SNe Ia belong to the disc, rather than
the bulge component. The radial distribution of SNe Ia in S0-S0/a galaxies is
inconsistent with their distribution in Sa-Sm hosts, which is probably due to
the contribution of the outer bulge SNe Ia in S0-S0/a galaxies. The radial
distributions of both types of SNe are similar in all the subsamples of Sa-Sbc
and Sc-Sm galaxies. These results confirm that the old bulges of Sa-Sm galaxies
are not significant producers of Type Ia SNe, while the bulge populations are
significant for SNe Ia only in S0-S0/a galaxies.


title: Synchronization of oscillators through time-shifted common inputs

abstract:
  Shared upstream dynamical processes are frequently the source of common
inputs in various physical and biological systems. However, due to finite
signal transmission speeds and differences in the distance to the source, time
shifts between otherwise common inputs are unavoidable. Since common inputs can
be a source of correlation between the elements of multi-unit dynamical
systems, regardless of whether these elements are directly connected with one
another or not, it is of importance to understand their impact on
synchronization. As a canonical model that is representative for a variety of
different dynamical systems, we study limit-cycle oscillators that are driven
by stochastic time-shifted common inputs. We show that if the oscillators are
coupled, time shifts in stochastic common inputs do not simply shift the
distribution of the phase differences, but rather the distribution actually
changes as a result. The best synchronization is therefore achieved at a
precise intermediate value of the time shift, which is due to a resonance-like
effect with the most probable phase difference that is determined by the
deterministic dynamics.


title: Paul L\'evy, strong approximation and the St. Petersburg paradox

abstract:
  This paper discusses a forgotten remark of Paul L\'evy (1935), determining
the asymptotic distribution of sums of i.i.d. random variables with tails
$cx^{-\alpha}\psi(\log x)$, where $0<\alpha<2$ and $\psi$ is a periodic
function on $\mathbb R$. Such sums occur in the St. Petersburg paradox and
L\'evy's results precede the crucial results of Martin-L\"of (1985) and
Cs\"org\H{o} and Dodunekova (1991) on the paradox by 50 years. L\'evy's proof
uses a coupling argument similar to Skorohod representation and provides a
strong (pointwise) approximation result, the first in probability theory. In
the same paper, L\'evy also proves limit theorems for i.i.d. sums by using the
quantile transform, another 'first' in the theory.


title: On L.G. Kov\`acs' problem

abstract:
  "Kourovka notebook" contains the question due to L.G. Kov\`acs (Problem
8.23): If the dihedral group $D$ of order 18 is a section of a direct product
$X\times Y$, must at least one of $X$ and $Y$ have a section isomorphic to $D$?
The goal of our short paper is to give the positive answer to this question
provided that $X$ and $Y$ are locally finite. In fact, we prove even more: If a
non-trivial semidirect product $D=A\rtimes B$ of a cyclic $p$-group $A$ and a
group $B$ of order $q$, where $p$ and $q$ are distinct primes, lies in a
locally finite variety generated by a set $\mathfrak{X}$ of groups, then $D$ is
a section of a group from $\mathfrak{X}$.


title:
New ultracool subdwarfs identified in large-scale surveys using Virtual
  Observatory tools: II. SDSS DR7 vs UKIDSS LAS DR6, SDSS DR7 vs UKIDSS LAS
  DR8, SDSS DR9 vs UKIDSS LAS DR10, and SDSS DR7 vs 2MASS

abstract:
  We aim at developing an efficient method to search for late-type subdwarfs
(metal-depleted dwarfs with spectral types >M5) to improve the current
statistics. Our objectives are: improve our knowledge of metal-poor low-mass
dwarfs, bridge the gap between the late-M and L types, determine their surface
density, and understand the impact of metallicity on the stellar and substellar
mass function.
  We carried out a search cross-matching the SDSS, 2MASS, and UKIDSS using
STILTS, Aladin, and Topcat. We considered different photometric and proper
motion criteria for our selection. We identified 29 and 71 late-type subdwarf
candidates in each cross-correlation over 8826 and 3679 square degrees,
respectively. We obtained low-resolution optical spectra for 71 of our
candidates with GTC, NOT, and VLT and retrieved spectra for 30 candidates from
the SDSS spectroscopic database. We classified 92 candidates based on 101
optical spectra using two methods: spectral indices and comparison with
templates of known subdwarfs.
  We confirmed 86% and 94% of the candidates as late-type subdwarfs from the
SDSS vs 2MASS and SDSS vs UKIDSS cross-matches, respectively. These subdwarfs
have spectral types ranging between M5 and L0.5 and SDSS magnitudes in the
r=19.4-23.3 mag range. Our new late-type M discoveries include 49 subdwarfs, 25
extreme subdwarfs, six ultrasubdwarfs, one subdwarf/extreme subdwarf, and two
dwarfs/subdwarfs. We derived a surface density of late-type subdwarfs of
0.040$^{+0.012}_{-0.007}$ per square degree in the SDSS DR7 vs UKIDSS LAS DR10
cross-match. We also checked the AllWISE photometry of known and new subdwarfs
and found that mid-infrared colours of M subdwarfs do not appear to differ from
their solar-metallicity counterparts of similar spectral types. However, the
J-W2 and J-W1 colours are bluer for lower metallicity dwarfs. (abstract
strongly abridged)


title: Radiative diagnostics in the solar photosphere and chromosphere

abstract:
  Magnetic fields on the surface of the Sun and stars in general imprint or
modify the polarization state of the electromagnetic radiation that is leaving
from the star. The inference of solar/stellar magnetic fields is performed by
detecting, studying and modeling polarized light from the target star. In this
review we present an overview of techniques that are used to study the
atmosphere of the Sun, and particularly those that allow to infer magnetic
fields. We have combined a small selection of theory on polarized radiative
transfer, inversion techniques and we discuss a number of results from
chromospheric inversions.


title: Infinite-dimensional features of matrices and pseudospectra

abstract:
  Given a Hilbert space operator $T$, the level sets of function
$\Psi_T(z)=\|(T-z)^{-1}\|^{-1}$ determine the so-called pseudospectra of $T$.
We set $\Psi_T$ to be zero on the spectrum of $T$. After giving some elementary
properties of $\Psi_T$ (which, as it seems, were not noticed before), we apply
them to the study of the approximation. We prove that for any operator $T$,
there is a sequence $\{T_n\}$ of finite matrices such that $\Psi_{T_n}(z)$
tends to $\Psi_{T}(z)$ uniformly on $\C$. In this proof, quasitriangular
operators play a special role. This is merely an existence result, we do not
give a concrete construction of this sequence of matrices.
  One of our main points is to show how to use infinite-dimensional operator
models in order to produce examples and counterexamples in the set of finite
matrices of large order. In particular, we get a result, which means, in a
sense, that the pseudospectrum of a nilpotent matrix can be anything one can
imagine. We also study the norms of the multipliers in the context of
Cowen--Douglas class operators. We use these results to show that, to the
opposite to the function $\Psi_{S}$, the function $\|\sqrt{S-z}\,\|$ for
certain finite matrices $S$ may oscillate arbitrarily fast even far away from
the spectrum.


title: Asynchronous Stochastic Gradient Descent with Delay Compensation

abstract:
  With the fast development of deep learning, it has become common to learn big
neural networks using massive training data. Asynchronous Stochastic Gradient
Descent (ASGD) is widely adopted to fulfill this task for its efficiency, which
is, however, known to suffer from the problem of delayed gradients. That is,
when a local worker adds its gradient to the global model, the global model may
have been updated by other workers and this gradient becomes "delayed". We
propose a novel technology to compensate this delay, so as to make the
optimization behavior of ASGD closer to that of sequential SGD. This is
achieved by leveraging Taylor expansion of the gradient function and efficient
approximation to the Hessian matrix of the loss function. We call the new
algorithm Delay Compensated ASGD (DC-ASGD). We evaluated the proposed algorithm
on CIFAR-10 and ImageNet datasets, and the experimental results demonstrate
that DC-ASGD outperforms both synchronous SGD and asynchronous SGD, and nearly
approaches the performance of sequential SGD.


title: Geometric characterization of flat modules

abstract:
  Let $R$ be a commutative ring. Roughly speaking, we prove that an $R$-module
$M$ is flat iff it is a direct limit of $R$-module affine algebraic varieties,
and $M$ is a flat Mittag-Leffler module iff it is the union of its
$R$-submodule affine algebraic varieties.


title: SAFIP: a streaming algorithm for inverse problems

abstract:
  This paper presents a new algorithm which aims at the resolution of inverse
problems of the form f(x) = 0, for x a vector of dimension d and f an arbitrary
function with mild regularity condition. The set of solutions S may be
infinite. This algorithm produces a good coverage of S, with a limited number
of evaluations of the function f. It is therefore appropriate for complex
problems where those evaluations are costly. Various examples are presented,
with d varying from 2 to 10. Proofs of convergence and of coverage of S are
presented.


title:
Spontaneous down conversion of surface plasmon polaritons: strong-field
  consideration

abstract:
  A non-perturbative theory of the spontaneous down conversion (SDC) of surface
plasmon polaritons at a metal-dielectric interface is presented. It is shown
that the process is resonantly enhanced for the characteristic power of
excitation, typically of the order of tens of watts. At a stronger excitation
the yield of SDC decreases rapidly. At a stronger excitation the yield of SDC
decreases rapidly. The reason for this decrease is the high rate of the change
of surface plasmon polaritons by the laser field, exceeding the rate of the
zero-point fluctuations responsible for the SDC process. The obtained results
may help one to construct miniature sources of entangled photons for quantum
communication.


title: Secret Key Generation over Noisy Channels with Correlated Sources

abstract:
  This paper investigates the problem of secret key generation over a wiretap
channel when the terminals observe correlated sources. These sources are
independent of the main channel and the users overhear them before the
transmission takes place. A novel achievable scheme is proposed, and its
optimality is shown under certain less-noisy conditions. This result improves
upon the existing literature where the more stringent condition of degradedness
is required. Furthermore, numerical evaluation of the proposed scheme and
previously reported results for a binary model are presented; a comparison of
the numerical bounds provides insights on the benefit of the novel scheme.


title: Drawing a Waddington landscape to capture dynamic epigenetics

abstract:
  Epigenetics is most often reduced to chromatin marking in the current
literature, whereas this notion was initially defined in a more general
context. This restricted view ignores that epigenetic memories are in fact more
robustly ensured in living systems by steady state mechanisms with permanent
molecule renewal. This misconception is likely to result from misleading
intuitions and insufficient dialogues between traditional and quantitative
biologists. To demystify dynamic epigenetics, its most famous image, a
Waddington landscape and its attractors, are explicitly drawn. The simple
example provided is sufficient to highlight the main requirements and
characteristics of dynamic gene networks, underlying cellular differentiation,
de-differentiation and trans-differentiation.


title:
Nano-scale thermal transfer -- an invitation to fluctuation
  electrodynamics

abstract:
  An electromagnetic theory of thermal radiation is outlined, based on the
fluctuation electrodynamics of Rytov and co-workers. We discuss the basic
concepts and the status of different approximations. The physical content is
illustrated with a few examples on near-field heat transfer.


title:
A Noninvasive Magnetic Stimulator Utilizing Secondary Ferrite Cores and
  Resonant Structures for Field Enhancement

abstract:
  In this paper, secondary ferrite cores and resonant structures have been used
for field enhancement. The tissue was placed between the double square source
coil and the secondary ferrite core. Resonant coils were added which aided in
modulating the electric field in the tissue. The field distribution in the
tissue was measured using electromagnetic simulations and ex-vivo measurements
with tissue. Calculations involve the use of finite element analysis (Ansoft
HFSS) to represent the electrical properties of the physical structure. The
setup was compared to a conventional design in which the secondary ferrite
cores were absent. It was found that the induced electric field could be
increased by 122%, when ferrite cores were placed below the tissue at 450 kHz
source frequency. The induced electric field was found to be localized in the
tissue, verified using ex-vivo experiments. This preliminary study maybe
further extended to establish the verified proposed concept with different
complicated body parts modelled using the software and in-vivo experiments as
required to obtain the desired induced field.


title: On the well-posedness of the inviscid SQG equation

abstract:
  In this paper we consider the inviscid SQG equation on the Sobolev spaces
$H^s(\R^2)$, $s > 2$. Using a geometric approach we show that for any $T > 0$
the corresponding solution map, $\theta(0) \mapsto \theta(T)$, is nowhere
locally uniformly continuous.


title:
Shifting the phase of a coherent beam with a $^{174}$Yb$^+$ ion:
  influence of the scattering cross section

abstract:
  We discuss and measure the phase shift imposed onto a radially polarized
light beam when focusing it onto an $^{174}\text{Yb}^{+}$ ion. In the
derivation of the expected phase shifts we include the properties of the
involved atomic levels. Furthermore, we emphasize the importance of the
scattering cross section and its relation to the efficiency for coupling the
focused light to an atom. The phase shifts found in the experiment are
compatible with the expected ones when accounting for known deficiencies of the
focusing optics and the motion of the trapped ion at the Doppler limit of laser
cooling.


title: Bounds on Traceability Schemes

abstract:
  The Stinson-Wei traceability scheme (known as traceability scheme) was
proposed for broadcast encryption as a generalization of the Chor-Fiat-Naor
traceability scheme (known as traceability code). Cover-free family was
introduced by Kautz and Singleton in the context of binary superimposed code.
In this paper, we find a new relationship between a traceability scheme and a
cover-free family, which strengthens the anti-collusion strength from $t$ to
$t^2$, that is, a $t$-traceability scheme is a $t^2$-cover-free family. Based
on this interesting discovery, we derive new upper bounds for traceability
schemes. By using combinatorial structures, we construct several infinite
families of optimal traceability schemes which attain our new upper bounds. We
also provide a constructive lower bound for traceability schemes, the size of
which has the same order with our general upper bound. Meanwhile, we consider
parent-identifying set system, an anti-collusion key-distributing scheme
requiring weaker conditions than traceability scheme but stronger conditions
than cover-free family. A new upper bound is also given for parent-identifying
set systems.


title: Multi-task Recurrent Model for True Multilingual Speech Recognition

abstract:
  Research on multilingual speech recognition remains attractive yet
challenging. Recent studies focus on learning shared structures under the
multi-task paradigm, in particular a feature sharing structure. This approach
has been found effective to improve performance on each individual language.
However, this approach is only useful when the deployed system supports just
one language. In a true multilingual scenario where multiple languages are
allowed, performance will be significantly reduced due to the competition among
languages in the decoding space. This paper presents a multi-task recurrent
model that involves a multilingual speech recognition (ASR) component and a
language recognition (LR) component, and the ASR component is informed of the
language information by the LR component, leading to a language-aware
recognition. We tested the approach on an English-Chinese bilingual recognition
task. The results show that the proposed multi-task recurrent model can improve
performance of multilingual recognition systems.