title:
Knowledge Extraction and Knowledge Integration governed by
  {\L}ukasiewicz Logics

abstract:
  The development of machine learning in particular and artificial intelligent
in general has been strongly conditioned by the lack of an appropriate
interface layer between deduction, abduction and induction. In this work we
extend traditional algebraic specification methods in this direction. Here we
assume that such interface for AI emerges from an adequate Neural-Symbolic
integration. This integration is made for universe of discourse described on a
Topos governed by a many-valued {\L}ukasiewicz logic. Sentences are integrated
in a symbolic knowledge base describing the problem domain, codified using a
graphic-based language, wherein every logic connective is defined by a neuron
in an artificial network. This allows the integration of first-order formulas
into a network architecture as background knowledge, and simplifies symbolic
rule extraction from trained networks. For the train of such neural networks we
changed the Levenderg-Marquardt algorithm, restricting the knowledge
dissemination in the network structure using soft crystallization. This
procedure reduces neural network plasticity without drastically damaging the
learning performance, allowing the emergence of symbolic patterns. This makes
the descriptive power of produced neural networks similar to the descriptive
power of {\L}ukasiewicz logic language, reducing the information lost on
translation between symbolic and connectionist structures. We tested this
method on the extraction of knowledge from specified structures. For it, we
present the notion of fuzzy state automata, and we use automata behaviour to
infer its structure. We use this type of automata on the generation of models
for relations specified as symbolic background knowledge.


title: Dual-Timescale Spectrum Management in Small-Cell Wireless Networks

abstract:
  To attain the targeted data rates of next generation cellular networks
requires dense deployment of small cells in addition to macro cells which
provide wide coverage. Dynamic radio resource management is crucial to the
success of such heterogeneous networks due to much more pronounced traffic and
interference variations in small cells. This work proposes a framework for
spectrum management organized according to two timescales, which include 1)
centralized optimization on a moderate timescale corresponding to typical
duration of user sessions (several seconds to minutes in today's networks), and
2) distributed spectrum allocation on a fast timescale corresponding to typical
latency requirements (a few milliseconds). An optimization problem is
formulated to allocate resources on the slower timescale with consideration of
(distributed) opportunistic scheduling on the faster timescale. Both fixed and
fully flexible user association schemes are considered. Iterative algorithms
are developed to solve these optimization problems efficiently for a cluster of
cells with guaranteed convergence. Simulation results demonstrate advantages of
the proposed framework and algorithms.


title: Private Web Search with an Expected Constant Round

abstract:
  Web searching is becoming an essential activity because it is often the most
effective and convenient way of finding information. However, a Web search can
be a threat to the privacy of the searcher because the queries may reveal
sensitive information about the searcher. Private Web search (PWS) solutions
allow users to find information on the Internet while preserving their privacy.
Here, privacy means maintaining the confidentiality of the identity of the
communicating users. According to their underlying technology, existing PWS
solutions can be divided into three types: proxy-based solutions,
obfuscation-based solutions, and cryptography-based solutions. Of these,
cryptography-based PWS (CB-PWS) systems are particularly interesting because
they provide strong privacy guarantees in the cryptographic sense. In this
paper, we present a round-efficient CB-PWS protocol that preserves
computational efficiency compared to other known CB-PWS systems. Assuming a
broadcast channel, our protocol is a \emph{four-round} cryptographic scheme
that requires $O(n)$ communication complexity. However, if only point-to-point
interaction is available, with the users emulating the broadcast channel, our
protocol requires an expected $O(1)$-round complexity and the same computation
and communication overhead. Further analyzing the efficiency of our protocol
shows that our proposal requires only $3n$ modular exponentiations for $n$
users. To evaluate the security of our protocol, we demonstrate that our
construction is secure in terms of a semi-honest model. We then discuss how to
enhance its security to render it secure in the presence of malicious
adversaries. We provide a specific protocol for managing users' groups, which
is also an advantage over existing systems.


title: Lower and upper bounds for entanglement of R\'enyi-$\alpha$ entropy

abstract:
  Entanglement R\'enyi-$\alpha$ entropy is an entanglement measure. It
generalizes the entanglement of formation, and they coincide when $\alpha$
tends to 1. We derive analytical lower and upper bounds for the entanglement
R\'enyi-$\alpha$ entropy of arbitrary dimensional bipartite quantum systems. We
also demonstrate the application our bound for some concrete examples.
Moreover, we establish the relation between entanglement R\'enyi-$\alpha$
entropy and some other entanglement measures.


title:
Multi-diagrams of relations between fuzzy sets: weighted limits,
  colimits and commutativity

abstract:
  Limits and colimits of diagrams, defined by maps between sets, are universal
constructions fundamental in different mathematical domains and key concepts in
theoretical computer science. Its importance in semantic modeling is described
by M. Makkai and R. Par\'e, where it is formally shown that every axiomatizable
theory in classical infinitary logic can be specified using diagrams defined by
maps between sets, and its models are structures characterized by the
commutativity, limit and colimit of those diagrams. Z. Diskin taking a more
practical perspective, presented an algebraic graphic-based framework for data
modeling and database design. The aim of our work is to study the possibility
of extending these algebraic frameworks to the specification of fuzzy
structures and to the description of fuzzy patterns on data. For that purpose,
in this paper we describe a conservative extension for the notions of diagram
commutativity, limit and colimit, when diagrams are constructed using relations
between fuzzy sets, evaluated in a multi-valued logic. These are used to
formalize what we mean by "a relation $R$ is similar to a limit of diagram
$D$," "a similarity relation $S$ is identical to a colimit of diagram $D$
colimit," and "a diagram $D$ is almost commutative."


title:
Chaotic motion of particles in the accelerating and rotating black holes
  spacetime

abstract:
  We have investigated the motion of timelike particles along geodesic in the
background of accelerating and rotating black hole spacetime. We confirmed that
the chaos exists in the geodesic motion of the particles by Poincar\'e
sections, the power spectrum, the fast Lyapunov exponent indicator and the
bifurcation diagram. Moreover, we probe the effects of the acceleration and
rotation parameters on the chaotic behavior of a timelike geodesic particle in
the black hole spacetime. Our results show that the acceleration brings richer
physics for the geodesic motion of particles.


title:
Ferro-deformation and shape coexistence over the nuclear chart: 28 <
  protons (Z) < 50 and 40 < neutrons (N) < 70

abstract:
  With the experimental data at the national nuclear data center, NNDC, we
investigate systematically the emerging nuclear structure properties in the
first 2+ excited energies, E(2+) and their energy ratios to the first 4+
levels, R = E(4+)/E(2+) in the nuclei over 28 < Z < 50 for protons, and 40 < N
< 70 for neutrons. By introducing the pseudo-shell configurations built on the
combined subshells, we explain the following phenomena; a semi-double shell
closure, a shape phase transition, and a reinforced deformation. The reinforced
deformation arises suddenly at Z = 40 (or 38), N = 60 and approaches a maximum
value, R = 3.3, as being centered at Z = 40, N = 64. We define this reinforced
deformation 'a ferro-deformation', as in the previous study [arXiv:1604.01017].
The shape coexistence would be expected to be, as forming a ferro-deformation,
with a strong rotational mode, and a near spherical shape, with a vibrational
mode, in the transitional region at N = 58, 60, and 62 for the nuclei, with Z =
38 and 40; 96Sr, 98Sr, 100Sr, and 98Zr, 100Zr, and 102Zr. We suggest that the
ferro-deformation should be closely associated with a strong spin-orbital
interaction between neutrons in the g7/2 orbital and protons in the g9/2
orbital. Such an isospin dependent spin-orbital interaction, with the same
angular momentum, l = 4, reinforces nuclear surface toward a sudden and
dramatic deformation, giving rise to the ferro-deformation at the critical
point, Z = 40, N = 64. We discuss the similarities and differences of the
ferro-deformation between the two critical points; Z = 40, N = 64 and Z = 64, N
= 104.


title:
Explicit symplectic algorithms based on generating functions for charged
  particle dynamics

abstract:
  Dynamics of a charged particle in the canonical coordinates is a Hamiltonian
system, and the well-known symplectic algorithm has been regarded as the de
facto method for numerical integration of Hamiltonian systems due to its
long-term accuracy and fidelity. For long-term simulations with high
efficiency, explicit symplectic algorithms are desirable. However, it is widely
accepted that explicit symplectic algorithms are only available for
sum-separable Hamiltonians, and that this restriction severely limits the
application of explicit symplectic algorithms to charged particle dynamics. To
overcome this difficulty, we combine the familiar sum-split method and a
generating function method to construct second and third order explicit
symplectic algorithms for dynamics of charged particle. The generating function
method is designed to generate explicit symplectic algorithms for
product-separable Hamiltonian with form of
$H(\mathbf{p},\mathbf{q})=\mathbf{p}_{i}f(\mathbf{q})$ or
$H(\mathbf{p},\mathbf{q})=\mathbf{q}_{i}f(\mathbf{p})$. Applied to the
simulations of charged particle dynamics, the explicit symplectic algorithms
based on generating functions demonstrate superiorities in conservation and
efficiency.


title:
Molecular dynamics simulation of behaviour of water in nano-confined
  ionic liquid--water mixtures

abstract:
  This work describes the behaviour of water molecules in
1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid under
nanoconfinement between graphene sheets. By means of molecular dynamics
simulations, an adsorption of water molecules at the graphene surface is
studied. A depletion of water molecules in the vicinity of the neutral and
negatively charged graphene surfaces and their adsorption at the positively
charged surface are observed in line with the preferential hydration of the
ionic liquid anions. The findings are appropriately described using a two-level
statistical model. The confinement effect on the structure and dynamics of the
mixtures is thoroughly analyzed using the density and the potential of mean
force profiles, as well as by the vibrational densities of states of water
molecules near the graphene surface. The orientation of water molecules and the
water-induced structural transitions in the layer closest to the graphene
surface are also discussed.


title:
An alternative proof of a sharp generalization of an integral inequality
  for the dyadic maximal operator and applications

abstract:
  We give an alternative proof of a sharp generalization of an integral
inequality for the dyadic maximal operator due to which the evaluation of the
Bellman function of this operator with respect to two variables, is possible.
This last mentioned inequality, which was first noticed in [3],also generalizes
in a certain direction the results of [7].


title: Categorical semiotics

abstract:
  The integration of knowledge extracted from different models described by
domain experts or from models generated by machine learning algorithms is
strongly conditioned by the lack of an appropriated framework to specify and
integrate structures, learning processes, data transformations and data models
or data rules. In this work we extended algebraic specification methods to be
used in this type of framework. This methodology uses graphic structures
similar to Ehresmann's sketches interpreted on a fuzzy set universe. This
approach takes advantages of the sketches ability to integrate data
deterministic and nondeterministic structures. Selecting this strategy we also
try to take advantage on how the graphic languages, used in Category theory in
general and used for sketch definition in particular, are suited to reasoning
about problems, to structural description and to task specification and task
decomposition.


title: Covering complete partite hypergraphs by monochromatic components

abstract:
  A well-known special case of a conjecture attributed to Ryser states that
k-partite intersecting hypergraphs have transversals of at most k-1 vertices.
An equivalent form was formulated by Gy\'arf\'as: if the edges of a complete
graph K are colored with k colors then the vertex set of K can be covered by at
most k-1 sets, each connected in some color. It turned out that the analogue of
the conjecture for hypergraphs can be answered: Z. Kir\'aly proved that in
every k-coloring of the edges of the r-uniform complete hypergraph K^r (r >=
3), the vertex set of K^r can be covered by at most $\lceil k/r \rceil$ sets,
each connected in some color.
  Here we investigate the analogue problem for complete r-uniform r-partite
hypergraphs. An edge coloring of a hypergraph is called spanning if every
vertex is incident to edges of any color used in the coloring. We propose the
following analogue of Ryser conjecture.
  In every spanning (r+t)-coloring of the edges of a complete r-uniform
r-partite hypergraph, the vertex set can be covered by at most t+1 sets, each
connected in some color.
  Our main result is that the conjecture is true for 1 <= t <= r-1. We also
prove a slightly weaker result for t >= r, namely that t+2 sets, each connected
in some color, are enough to cover the vertex set.
  To build a bridge between complete r-uniform and complete r-uniform r-partite
hypergraphs, we introduce a new notion. A hypergraph is complete r-uniform
(r,l)-partite if it has all r-sets that intersect each partite class in at most
l vertices.
  Extending our results achieved for l=1, we prove that for any r >= 3, 2 <= l
<= r, k >= 1+r-l, in every spanning k-coloring of the edges of a complete
r-uniform (r,l)-partite hypergraph, the vertex set can be covered by at most
1+\lfloor \frac{k-r+\ell-1}{\ell}\rfloor sets, each connected in some color.


title: The Stiefel--Whitney theory of topological insulators

abstract:
  We study the topological band theory of time reversal invariant topological
insulators and interpret the topological $\mathbb{Z}_2$ invariant as an
obstruction in terms of Stiefel--Whitney classes. The band structure of a
topological insulator defines a Pfaffian line bundle over the momentum space,
whose structure group can be reduced to $\mathbb{Z}_2$. So the topological
$\mathbb{Z}_2$ invariant will be understood by the Stiefel--Whitney theory,
which detects the orientability of a principal $\mathbb{Z}_2$-bundle. Moreover,
the relation between weak and strong topological insulators will be understood
based on cobordism theory. Finally, the topological $\mathbb{Z}_2$ invariant
gives rise to a fully extended topological quantum field theory (TQFT).


title:
Gold nanoflowers as efficient hot-spots for surface enhanced Raman
  scattering

abstract:
  Gold nanoflowers are known for their use as efficient host for surface
enhanced Raman scattering of organic dye molecules. In this article, gold
nanoflowers have been synthesised and rhodamine 6 G (R6G) molecules have been
used as probe molecules. It is found that the gold nanoflowers can detect the
presence of R6G molecules upto 10^{-10} M. The petals of these nanoflowers play
an important role for the enhancement of Raman signals, and the intensity of
Raman signals is enhanced many folds in presence of gold nanoflowers - the
enhancement factor is of the order of 10^6. This is explained in terms of
electromagnetic mechanism.


title: Sub-photospheric shocks in relativistic explosions

abstract:
  This paper examines the mechanism of internal shocks in opaque relativistic
outflows, in particular in cosmological gamma-ray bursts. The shocks produce
neutrino emission and affect the observed photospheric radiation from the
explosion. They develop from internal compressive waves and can be of different
types depending on the composition of the outflow: (1) Shocks in "photon gas,"
with negligible plasma inertia, have a unique structure determined by the
force-free condition---zero radiation flux in the plasma rest frame. Radiation
dominance over plasma inertia suppresses formation of collisionless shocks
mediated by collective electromagnetic fields. (2) If the outflow is
sufficiently magnetized, a strong collisionless subshock develops, which is
embedded in a thicker radiation-mediated structure. (3) Waves in outflows with
a free neutron component lead to dissipation through nuclear collisions. At
large optical depths, shocks have a thickness comparable to the neutron free
path, with an embedded radiation-mediated and collisionless subshocks. The
paper also presents first-principle simulations of magnetized flows filled with
photons, demonstrating formation of shocks and their structure. Simple
estimates show that magnetized sub-photospheric shocks are efficient producers
of photons and have a great impact on the observed photospheric radiation. The
shock structure changes as the outflow expands toward its photosphere. The
dissipation is accompanied by strong $e^\pm$ pair creation, and the
$e^\pm$-dressed shock carries the photosphere with it up to two decades in
radius, emitting a strong pulse of nonthermal radiation.


title:
Matlis' semi-regularity in trivial ring extensions issued from integral
  domains

abstract:
  This paper contributes to the study of homological aspects of trivial ring
extensions (also called Nagata idealizations). Namely, we investigate the
transfer of the notion of (Matlis') semi-regular ring (also known as IF-ring)
along with related concepts, such as coherence, in trivial ring extensions
issued from integral domains. All along the paper, we put the new results in
use to enrich the literature with new families of examples subject to
semi-regularity.


title: Cross-Layer Design of Influence Maximization in Mobile Social Networks

abstract:
  Most prior algorithms for influence maximization focused are designed for
Online Social Networks (OSNs) and require centralized computation. Directly
deploying the above algorithms in distributed Mobile Social Networks (MSNs)
will overwhelm the networks due to an enormous number of messages required for
seed selection. In this paper, therefore, we design a new cross-layer strategy
to jointly examine MSN and mobile ad hoc networks (MANETs) to facilitate
efficient seed selection, by extracting a subset of nodes as agents to
represent nearby friends during the distributed computation. Specifically, we
formulate a new optimization problem, named Agent Selection Problem (ASP), to
minimize the message overhead transmitted in MANET. We prove that ASP is
NP-Hard and design an effectively distributed algorithm. Simulation results in
real and synthetic datasets manifest that the message overhead can be
significantly reduced compared with the existing approaches.


title: An Integrated Method of Data Hiding and Compression of Medical Images

abstract:
  A new technique for embedding data into an image coupled with compression has
been proposed in this paper. A fast and efficient coding algorithms are needed
for effective storage and transmission, due to the popularity of telemedicine
and the use of digital medical images. Medical images are produced and
transferred between hospitals for review by physicians who are geographically
apart. Such image data need to be stored for future reference of patients as
well. This necessitates compact storage of medical images before being
transmitted over Internet. Moreover, as the patient information is also
embedded within the medical images, it is very important to maintain the
confidentiality of patient data. Hence, this article aims at hiding patient
information as well, within the medical image followed by joint compression.
The hidden data and the host image are absolutely recoverable from the embedded
image without any loss.


title:
A fully relativistic description of spin-orbit torques by means of
  linear response theory

abstract:
  Symmetry and magnitude of spin-orbit torques (SOT), i.e., current-induced
torques on the magnetization of systems lacking inversion symmetry, are
investigated in a fully relativistic linear response framework based on the
Kubo formalism. By applying all space-time symmetry operations contained in the
magnetic point group of a solid to the relevant response coefficient, the
torkance expressed as torque-current correlation function, restrictions to the
shape of the direct and inverse response tensors are obtained. These are shown
to apply to the corresponding thermal analogues as well, namely the direct and
inverse thermal SOT in response to a temperature gradient or heat current.
Using an implementation of the Kubo-Bastin formula for the torkance into a
first-principles multiple-scattering Green's function framework and accounting
for disorder effects via the so-called coherent potential approximation (CPA),
all contributions to the SOT in pure systems, dilute as well as concentrated
alloys can be treated on equal footing. This way, material specific values for
all torkance tensor elements in the fcc (111) trilayer alloy system Pt |
Fe$_x$Co$_{1-x}$ | Cu are obtained over a wide concentration range and
discussed in comparison to results for electrical and spin conductivity, as
well as to previous work - in particular concerning symmetry w.r.t.
magnetization reversal and the nature of the various contributions.


title:
Design study of a beta=0.09 high current superconducting half wave
  resonator

abstract:
  There's presently a growing demand for high current proton and deuteron
linear accelerators based on superconducting technology to better support
various fields of science. A \b{eta}=0.09 162.5 MHz high current
superconducting half wave resonator (HWR) has been designed at Peking
University to accelerate 100 mA proton beam or 50 mA deuteron beam after the
RFQ accelerating structure. The detailed electromagnetic design, multipacting
simulation, mechanical analysis of the cavity will be given in this paper.


title:
OISTER Optical and Near-Infrared Observations of the Super-Chandrasekhar
  Supernova Candidate SN 2012dn: Dust Emission from the Circumstellar Shell

abstract:
  We present extensively dense observations of the super-Chandrasekhar
supernova (SC SN) candidate SN 2012dn from $-11$ to $+140$ days after the date
of its $B$-band maximum in the optical and near-infrared (NIR) wavelengths
conducted through the OISTER ToO program. The NIR light curves and color
evolutions up to 35 days after the $B$-band maximum provided an excellent match
with those of another SC SN 2009dc, providing a further support to the nature
of SN 2012dn as a SC SN. We found that SN 2012dn exhibited strong excesses in
the NIR wavelengths from $30$ days after the $B$-band maximum. The $H$ and
$K_{s}$-band light curves exhibited much later maximum dates at $40$ and $70$
days after the $B$-band maximum, respectively, compared with those of normal
SNe Ia. The $H$ and $K_{s}$-band light curves subtracted by those of SN 2009dc
displayed plateaued evolutions, indicating a NIR echo from the surrounding
dust. The distance to the inner boundary of the dust shell is limited to be
$4.8 - 6.4\times10^{-2}$ pc. No emission lines were found in its early phase
spectrum, suggesting that the ejecta-CSM interaction could not occur. On the
other hand, we found no signature that strongly supports the scenario of dust
formation. The mass loss rate of the pre-explosion system is estimated to be
$10^{-6}-10^{-5}$ M$_{\odot}$ yr$^{-1}$, assuming that the wind velocity of the
system is $10-100$ km~s$^{-1}$, which suggests that the progenitor of SN 2012dn
could be a recurrent nova system. We conclude that the progenitor of this SC SN
could be explained by the single-degenerate scenario.


title: Capturing Dynamic Textured Surfaces of Moving Targets

abstract:
  We present an end-to-end system for reconstructing complete watertight and
textured models of moving subjects such as clothed humans and animals, using
only three or four handheld sensors. The heart of our framework is a new
pairwise registration algorithm that minimizes, using a particle swarm
strategy, an alignment error metric based on mutual visibility and occlusion.
We show that this algorithm reliably registers partial scans with as little as
15% overlap without requiring any initial correspondences, and outperforms
alternative global registration algorithms. This registration algorithm allows
us to reconstruct moving subjects from free-viewpoint video produced by
consumer-grade sensors, without extensive sensor calibration, constrained
capture volume, expensive arrays of cameras, or templates of the subject
geometry.


title: Coverage Analysis of Heterogeneous Cellular Networks in Urban Areas

abstract:
  In this article, a network model incorporating both line-of-sight (LOS) and
non-line-of-sight (NLOS) transmissions is proposed to investigate impacts of
blockages in urban areas on heterogeneous network coverage performance. Results
show that co-existence of NLOS and LOS transmissions has a significant impact
on network performance. We find in urban areas, that deploying more BSs in
different tiers is better than merely deploying all BSs in the same tier in
terms of coverage probability.


title: Heavy Leptonium as the Origin of the 750 GeV Diphoton Excess

abstract:
  We propose a hypothetical heavy leptonium, the scalar bound state of an
exotic lepton-antilepton pair, as a candidate for the recent 750 GeV resonance
in the early LHC Run 2 data. Such a para-leptonium is dominantly produced via
photon-photon fusion at the LHC and decays into a photon pair with a
significant branching fraction. In addition, our model predicts a companion
spin-1 ortho-leptonium bound state, which can decay to $W^+W^-$, $f\bar{f}$ and
three photons. Under the LHC and the electroweak precision observables bounds,
we find that the observed excess of 750 GeV diphoton events can be explained
within $2\sigma$ accuracy for $Y_{L} \approx 4.8 - 7.2$ for the minimal case in
our scenario. The observation of the ortho-leptonium in the dilepton channel
will be the smoking gun for our scenario.


title: Zero-knowledge proof systems for QMA

abstract:
  Prior work has established that all problems in NP admit classical
zero-knowledge proof systems, and under reasonable hardness assumptions for
quantum computations, these proof systems can be made secure against quantum
attacks. We prove a result representing a further quantum generalization of
this fact, which is that every problem in the complexity class QMA has a
quantum zero-knowledge proof system. More specifically, assuming the existence
of an unconditionally binding and quantum computationally concealing commitment
scheme, we prove that every problem in the complexity class QMA has a quantum
interactive proof system that is zero-knowledge with respect to efficient
quantum computations.
  Our QMA proof system is sound against arbitrary quantum provers, but only
requires an honest prover to perform polynomial-time quantum computations,
provided that it holds a quantum witness for a given instance of the QMA
problem under consideration. The proof system relies on a new variant of the
QMA-complete local Hamiltonian problem in which the local terms are described
by Clifford operations and standard basis measurements. We believe that the
QMA-completeness of this problem may have other uses in quantum complexity.


title:
{\L}ojasiewicz inequalities with explicit exponent for smallest singular
  value functions

abstract:
  Let $F(x) := (f_{ij}(x))_{i=1,\ldots,p; j=1,\ldots,q},$ be a ($p\times
q$)-real polynomial matrix and let $f(x)$ be the smallest singular value
function of $F(x).$ In this paper, we first give the following {\em nonsmooth}
version of \L ojasiewicz gradient inequality for the function $f$ with an
explicit exponent: {\em For any $\bar x\in \Bbb R^n$, there exist $c > 0$ and
$\epsilon > 0$ such that we have for all $\|x - \bar{x}\| < \epsilon,$
\begin{equation*} \inf \{ \| w \| \ : \ w \in {\partial} f(x) \} \ \ge \ c\,
|f(x)-f(\bar x)|^{1 - \frac{2}{\mathscr R(n+p,2d+2)}}, \end{equation*} where
${\partial} f(x)$ is the limiting subdifferential of $f$ at $x$,
$d:=\max_{i=1,\ldots,p; j=1,\ldots,q}\deg f_{i j}$ and $\mathscr R(n, d) :=
d(3d - 3)^{n-1}$ if $d \ge 2$ and $\mathscr R(n, d) := 1$ if $d = 1.$} Then we
establish some versions of \L ojasiewicz inequality for the distance function
with explicit exponents, locally and globally, for the smallest singular value
function $f(x)$ of the matrix $F(x)$.


title:
Nodal gap detection through polar angle-resolved density of states
  measurements in uniaxial superconductors

abstract:
  We propose a spectroscopic method to identify the nodal gap structure in
unconventional superconductors. This method best suits for locating the
horizontal line node and for pinpointing the isolated point nodes by measuring
polar angle ($\theta$) resolved zero energy density of states $N(\theta)$. This
is measured by specific heat or thermal conductivity at low temperatures under
a magnetic field. We examine a variety of uniaxially symmetric nodal structure,
including point and/or line nodes with linear and quadratic dispersions, by
solving Eilenberger equation in vortex states. It is found that (A) the maxima
of $N(\theta)$ continuously shift from the anti-nodal to the nodal direction
($\theta_{\rm n}$) as a field increases accompanying the oscillation pattern
reversal at low and high fields. Furthermore, (B) local minima emerge next to
$\theta_{\rm n}$ on both sides except for the case of linear point node. These
features are robust and detectable experimentally. Experimental results of
$N(\theta)$ performed on several superconductors, UPd$_2$Al$_3$, URu$_2$Si$_2$,
Cu$_x$Bi$_2$Se$_3$, and UPt$_3$, are examined and commented in light of the
present theory.


title: Minimal model for charge transfer excitons at the dielectric interface

abstract:
  Theoretical description of the charge transfer (CT) exciton across the
donor-acceptor interface without the use of a completely localized hole (or
electron) is a challenge in the field of organic solar cells. We calculate the
total wavefunction of the CT exciton by solving an effective two-particle
Schrodinger equation for the inhomogeneous dielectric interface. We formulate
the magnitude of the CT and construct a minimal model of the CT exciton under
the breakdown of inversion symmetry. We demonstrate that both a light hole mass
and a hole localization along the normal to the dielectric interface are
crucial to yield the CT exciton.


title: NTU RGB+D: A Large Scale Dataset for 3D Human Activity Analysis

abstract:
  Recent approaches in depth-based human activity analysis achieved outstanding
performance and proved the effectiveness of 3D representation for
classification of action classes. Currently available depth-based and
RGB+D-based action recognition benchmarks have a number of limitations,
including the lack of training samples, distinct class labels, camera views and
variety of subjects. In this paper we introduce a large-scale dataset for RGB+D
human action recognition with more than 56 thousand video samples and 4 million
frames, collected from 40 distinct subjects. Our dataset contains 60 different
action classes including daily, mutual, and health-related actions. In
addition, we propose a new recurrent neural network structure to model the
long-term temporal correlation of the features for each body part, and utilize
them for better action classification. Experimental results show the advantages
of applying deep learning methods over state-of-the-art hand-crafted features
on the suggested cross-subject and cross-view evaluation criteria for our
dataset. The introduction of this large scale dataset will enable the community
to apply, develop and adapt various data-hungry learning techniques for the
task of depth-based and RGB+D-based human activity analysis.


title: Isolating the Lyman Alpha Forest BAO Anomaly

abstract:
  A 2.5-3 sigma discrepancy has been reported between the baryonic acoustic
oscillation peak (BAO) in the Lyman $\alpha$ forest at $z\sim 2.34$ and the
best fit Planck $\Lambda$CDM cosmology. To isolate the origin of the tension,
we consider unanchored BAO, in which the standard BAO ruler is not calibrated,
eliminating any dependence on cosmology before redshift $z\sim 2.34$. We
consider BOSS BAO measurements at $z\sim 0.32$, 0.57 and 2.34, using the full
2-dimensional constraints on the angular and line of sight BAO scale, as well
as isotropic BAO measurements by 6dF and SDSS at $z\sim 0.106$ and $z\sim
0.15$. We find that the $z>0.43$ data alone is in 2.9 sigma of tension with
$\Lambda$CDM with or without the Planck best fit values of the mass fraction
$\Omega_m$ and the BAO scale $r_d H_0$, indicating that the tension arises not
from the $\Lambda$CDM parameters but from the dark energy evolution itself at
0.57<z<2.34. This conclusion is supported when the acoustic scale measured by
the CMB is included, which further increases the tension and excludes a
solution with a constant dark energy equation of state. Including the low $z$
BAO data, which is itself consistent with $\Lambda$CDM, reduces the tension to
just over 2 sigma, however in this case a CPL parametrization of the dark
energy evolution yields only a modest improvement.


title: High order approximation to non-smooth multivariate functions

abstract:
  Approximations of non-smooth multivariate functions return low-order
approximations in the vicinities of the singularities. Most prior works solve
this problem for univariate functions. In this work we introduce a method for
approximating non-smooth multivariate functions of the form $f = g + r_+$ where
$g,r \in C^{M+1}(\mathbb{R}^n)$ and the function $r_+$ is defined by \[ r_+(y)
= \left\{ \begin{array}{ll} r(y), & r(y) \geq 0 \\ 0, & r(y) < 0 \end{array}
\right. \ , \ \forall y \in \mathbb{R}^n \ . \] Given scattered (or uniform)
data points $X \subset \mathbb{R}^n$, we investigate approximation by
quasi-interpolation. We design a correction term, such that the corrected
approximation achieves full approximation order on the entire domain. We also
show that the correction term is the solution to a Moving Least Squares (MLS)
problem, and as such can both be easily computed and is smooth. Last, we prove
that the suggested method includes a high-order approximation to the locations
of the singularities.


title: On the mass-coupling relation of multi-scale quantum integrable models

abstract:
  We determine exactly the mass-coupling relation for the simplest multi-scale
quantum integrable model, the homogenous sine-Gordon model with two independent
mass-scales. We first reformulate its perturbed coset CFT description in terms
of the perturbation of a projected product of minimal models. This
representation enables us to identify conserved tensor currents on the UV side.
These UV operators are then mapped via form factor perturbation theory to
operators on the IR side, which are characterized by their form factors. The
relation between the UV and IR operators is given in terms of the sought-for
mass-coupling relation. By generalizing the $\Theta$ sum rule Ward identity we
are able to derive differential equations for the mass-coupling relation, which
we solve in terms of hypergeometric functions. We check these results against
the data obtained by numerically solving the thermodynamic Bethe Ansatz
equations, and find a complete agreement.


title: C*-Convexity of Norm Unit Balls

abstract:
  We determine those norms on B(H) whose unit ball is C*-convex. We call them
M-norms and show that the class of M-norms less than a given norm enjoys a
maximum element. These minimum and maximum elements will be determined in some
cases. Finally, we give a constructive result to obtain M-norms on B(H).


title: Auslander-Reiten duality for Grothendieck abelian categories

abstract:
  Auslander-Reiten duality for module categories is generalised to Grothendieck
abelian categories that have a sufficient supply of finitely presented objects.
It is shown that Auslander-Reiten duality amounts to the fact that the functor
Ext^1(C,-) into modules over the endomorphism ring of C admits a partially
defined right adjoint when C is a finitely presented object. This result seems
to be new even for module categories. For appropriate schemes over a field, the
connection with Serre duality is discussed.


title: The topological transversal Tverberg theorem plus constraints

abstract:
  In this paper we use the strength of the constraint method in combination
with a generalized Borsuk-Ulam type theorem and a cohomological intersection
lemma to show how one can obtain many new topological transversal theorems of
Tverberg type. In particular, we derive a topological generalized transversal
Van Kampen-Flores theorem and a topological transversal weak colored Tverberg
theorem.


title: Beyond Brightness Constancy: Learning Noise Models for Optical Flow

abstract:
  Optical flow is typically estimated by minimizing a "data cost" and an
optional regularizer. While there has been much work on different regularizers
many modern algorithms still use a data cost that is not very different from
the ones used over 30 years ago: a robust version of brightness constancy or
gradient constancy. In this paper we leverage the recent availability of
ground-truth optical flow databases in order to learn a data cost. Specifically
we take a generative approach in which the data cost models the distribution of
noise after warping an image according to the flow and we measure the
"goodness" of a data cost by how well it matches the true distribution of flow
warp error. Consistent with current practice, we find that robust versions of
gradient constancy are better models than simple brightness constancy but a
learned GMM that models the density of patches of warp error gives a much
better fit than any existing assumption of constancy. This significant
advantage of the GMM is due to an explicit modeling of the spatial structure of
warp errors, a feature which is missing from almost all existing data costs in
optical flow. Finally, we show how a good density model of warp error patches
can be used for optical flow estimation on whole images. We replace the data
cost by the expected patch log-likelihood (EPLL), and show how this cost can be
optimized iteratively using an additional step of denoising the warp error
image. The results of our experiments are promising and show that patch models
with higher likelihood lead to better optical flow estimation.


title: Higher Order Cumulants in Colorless Partonic Plasma

abstract:
  Any physical system considered to study the QCD deconfinement phase
transition certainly has a finite volume, so the finite size effects are
inevitably present. This renders the location of the phase transition and the
determination of its order as an extremely difficult task, even in the simplest
known cases. In order to identify and locate the colorless QCD deconfinement
transition point in finite volume $T_{0}(V)$, a new approach based on the
finite-size cumulant expansion of the order parameter and the
$\mathscr{L}_{m,n}$-Method is used.We have shown that both cumulants of higher
order and their ratios, associated to the thermodynamical fluctuations of the
order parameter, in QCD deconfinement phase transition behave in a particular
enough way revealing pronounced oscillations in the transition region. The sign
structure and the oscillatory behavior of these in the vicinity of the
deconfinement phase transition point might be a sensitive probe and may allow
one to elucidate their relation to the QCD phase transition point. In the
context of our model, we have shown that the finite volume transition point is
always associated to the appearance of a particular point in whole higher order
cumulants under consideration.


title:
Injection locking of quantum dot microlasers operating in the few photon
  regime

abstract:
  We experimentally and theoretically investigate injection locking of quantum
dot (QD) microlasers in the regime of cavity quantum electrodynamics (cQED). We
observe frequency locking and phase-locking where cavity enhanced spontaneous
emission enables simultaneous stable oscillation at the master frequency and at
the solitary frequency of the slave microlaser. Measurements of the
second-order autocorrelation function prove this simultaneous presence of both
master and slave-like emission, where the former has coherent character with
$g^{(2)}(0)=1$ while the latter one has thermal character with $g^{(2)}(0)=2$.
Semi-classical rate-equations explain this peculiar behavior by cavity enhanced
spontaneous emission and a low number of photons in the laser mode.


title: A new method of creating high intensity neutron source

abstract:
  We propose a new scheme of producing intense neutron beam whose yields exceed
those of existing facilities by many orders of magnitude. This scheme uses the
recently proposed photon beam extracted from circulating quantum ions, which is
directed to a deuteron target for photo-disintegration. The calculated neutron
energy spectrum is nearly flat down to neV range, except a threshold rise and
its adjacent wide structure. Hence, there exists a possibility of directly
using sub-eV neutrons without a moderator. We shall have brief comments on
promising particle physics applications using this large yield of neutron.

categories: nucl-ex hep-ex hep-ph physics.acc-ph physics.atom-ph


title:
Interplays between charge and electric field in perovskite solar cells:
  charge transport, recombination and hysteresis

abstract:
  Interplays between charge and electric field, which play a critical role in
determining the charge transport, recombination, storage and hysteresis in the
perovskite solar cell, have been systematically investigated by both electrical
transient experiments and theoretical calculations. It is found that the light
illumination can increase the carrier concentration in the perovskite absorber,
thus enhancing charge recombination and causing the co-existence of high
electric field and free carriers. Meanwhile, the cell shows a similar charge
storage and junction mechanism to that of the multicrystalline silicon solar
cell, where the junction electric field determines the charge collection and
distribution. Furthermore, it is demonstrated that the static charge of both
the doping and defect coming from ion (vacancy) migration can significantly
influence the electric field inside the cell, thus affecting the charge
collection and recombination, which could be the origins for the
widely-concerned hysteresis behaviors.


title:
Reverse Shock Emission Driven By Post-Merger Millisecond Magnetar Winds:
  Effects of the Magnetization Parameter

abstract:
  The study of short-duration gamma-ray bursts provides growing evidence that a
good fraction of double neutron star mergers lead to the formation of stable
millisecond magnetars. The launch of Poynting flux by the millisecond magnetars
could leave distinct electromagnetic signatures that reveal the energy
dissipation processes in the magnetar wind. In previous studies (Wang & Dai
2013b; Wang et al. 2015), we assume that the magnetar wind becomes completely
lepton-dominated so that electrons/positrons in the magnetar wind are
accelerated by a diffusive shock. However, theoretical modeling of pulsar wind
nebulae shows that in many cases the magnetic field energy in the pulsar wind
may be strong enough to suppress diffusive shock acceleration. In this paper,
we investigate the reverse shock emission as well as the forward shock emission
with an arbitrary magnetization parameter $\sigma$ of a magnetar wind. We find
that the reverse shock emission strongly depends on $\sigma$, and in
particular, $\sigma \sim 0.3$ leads to the strongest reverse shock emission.
Future observations would be helpful to diagnose the composition of the
magnetar wind.


title:
Di-Higgs signatures from R-parity violating supersymmetry as the origin
  of neutrino mass

abstract:
  Motivated by the naturalness and neutrino mass generation, we study a
bilinear R-parity violating supersymmetric scenario with a light Higgsino-like
lightest supersymmetric particle (LSP). We observe that the LSP dominantly
decays to $\nu h$ in a large part of the parameter space, and thus study the
pair production of electroweakinos followed by the decays $\tilde\chi^\pm_1\to
\tilde\chi^0_1 W^{\pm*}$ and $\tilde\chi^0_1\to \nu h$. This leads to an
interesting signature of Higgs boson pair production associated with
significantly large missing transverse energy which is grossly distinct from
the di-Higgs production in the Standard Model. We investigate the perspective
of probing such signatures by performing a realistic detector level simulation
of both the signal and corresponding backgrounds for the high-luminosity high
energy phase of the Large Hadron Collider (LHC). We also advocate some
observables based on kinematical features to provide an excellent handle to
suppress the backgrounds.


title:
A combinatorial refinement of the Kronecker-Hurwitz class number
  relation

abstract:
  We give a refinement of the Kronecker-Hurwitz class number relation, based on
a tesselation of the Euclidean plane into semi-infinite triangles labeled by
$PSL_2(\mathbb{Z})$ that may be of independent interest.


title: Destruction of string order after a quantum quench

abstract:
  We investigate the evolution of string order in a spin-1 chain following a
quantum quench. After initializing the chain in the Affleck-Kennedy-Lieb-Tasaki
state, we analyze in detail how string order evolves as a function of time at
different length scales. The Hamiltonian after the quench is chosen either to
preserve or to suddenly break the symmetry which ensures the presence of string
order. Depending on which of these two situations arises, string order is
either preserved or lost even at infinitesimal times in the thermodynamic
limit. The fact that non-local order may be abruptly destroyed, what we call
string-order melting, makes it qualitatively different from typical order
parameters in the manner of Landau. This situation is thoroughly characterized
by means of numerical simulations based on matrix product states algorithms and
analytical studies based on a short-time expansion for several simplified
models.


title: Motion planning and motility maps for flagellar microswimmers

abstract:
  We study two microswimmers consisting of a spherical rigid head and a passive
elastic tail. In the first one the tail is clamped to the head, and the system
oscillates under the action of an external torque. In the second one, head and
tail are connected by a joint allowing the angle between them to vary
periodically, as a result of an oscillating internal torque. Previous studies
on these models were restricted to sinusoidal actuations, showing that the
swimmers can propel while moving on average along a straight line, in the
direction given by the symmetry axis around which beating takes place. We
extend these results to motions produced by generic (non-sinusoidal) periodic
actuations within the regime of small compliance of the tail. We find that
modulation in the velocity of actuation can provide a mechanism to select
different directions of motion. With velocity modulated inputs the externally
actuated swimmer can translate laterally with respect to the symmetry axis of
beating, while the internally actuated one is able to move along curved
trajectories. The governing equations are analysed with an asymptotic
perturbation scheme, providing explicit formulas whose results are expressed
through motility maps. Asymptotic approximations are further validated by
numerical simulations.


title: Optical Fiber MIMO Channel Model and its Analysis

abstract:
  Technology is moving towards space division multiplexing in optical fiber to
keep up the trend in rate increase over time and to avoid an imminent capacity
crunch. Thus, it is of paramount interest to estimate the potential gains of
this approach. As more spatial channels are being packed into a single fiber,
the increased crosstalk necessitates the use of MIMO to guarantee reliable
operation. In this paper, we exploit the analogy between an optical fiber and a
model from mesoscopic physics - a chaotic cavity - to obtain a novel channel
model for the optical fiber. The model captures both random distributed
crosstalk and modedependent loss, which are described within the framework of
scattering theory. Using tools from replica theory and random matrix theory, we
derive the capacity of the fiber optical MIMO channel model.


title:
The minimum sets and free boundaries of strictly plurisubharmonic
  functions

abstract:
  We study the minimum sets of plurisubharmonic functions with strictly
positive Monge-Amp\`ere densities. We investigate the relationship between
their Hausdorff dimension and the regularity of the function. Under suitable
assumptions we prove that the minimum set cannot contain analytic subvarieties
of large dimension. In the planar case we analyze the influence on the
regularity of the right hand side and consider the corresponding free boundary
problem with irregular data. We provide sharp examples for the Hausdorff
dimension of the minimum set and the related free boundary. We also draw
several analogues with the corresponding real results.


title:
On a classification of 4-d gradient Ricci solitons with harmonic Weyl
  curvature

abstract:
  We study a characterization of 4-dimensional (not necessarily complete)
gradient Ricci solitons $(M, g, f)$ which have harmonic Weyl curvature, i.e.
$\delta W=0$. Roughly speaking, we prove that the soliton metric $g$ is locally
isometric to one of the following four types: an Einstein metric, the product $
\mathbb{R}^2 \times N_{\lambda}$ of the Euclidean metric and a 2-d Riemannian
manifold of constant curvature ${\lambda} \neq 0$, a certain singular metric
and a locally conformally flat metric. The method here is motivated by
Cao-Chen's works \cite{CC1, CC2} and Derdzi\'{n}ski's study on Codazzi tensors
\cite{De}.
  Combined with the previous results on locally conformally flat solitons, our
characterization yields a new classification of 4-d complete steady solitons
with $\delta W=0$. For shrinking case, it reproves the rigidity result
\cite{FG, MS} in 4-d. It also helps to understand the expanding case; we now
understand all 4-d non-conformally-flat ones with $\delta W=0$. We also
characterize {\it locally} 4-d (not necessarily complete) gradient Ricci
solitons with harmonic curvature.


title:
Background-free coherent anti-stokes Raman spectroscopy and microscopy
  by dual-soliton pulse generation

abstract:
  We propose an all-fiber-generated dual-soliton pulses based scheme for the
background-free detection of coherent anti-Stokes Raman spectroscopy under the
spectral focusing mechanism. Due to the strong birefringence and high
nonlinearity of a polarization-maintaining photonic crystal fiber (PM-PCF), two
redshifted soliton pulses can be simultaneously generated relying on high-order
dispersion and nonlinear effects along two eigenpolarization axes in the
anomalous dispersion regime, while allowing feasible tunability of the
frequency distance and temporal interval between them. This proposed scheme,
termed as DS-CARS, exploits a unique combination of slight frequency-shift and
advisable temporal walk-off of this two soliton pulses to achieve robust and
efficient suppression of nonresonant background with compact all-fiber coherent
excitation source. Capability of the DS-CARS is experimentally demonstrated by
the background-free CARS spectroscopy and unambiguous CARS microscopy of
polymer beads in the fingerprint region.


title: Interatomic Fe-H potential for irradiation and embrittlement simulations

abstract:
  The behavior of hydrogen in iron and iron alloys is of interest in many
fields of physics and materials science. To enable large-scale molecular
dynamics simulations of systems with Fe-H interactions, we develop, based on
density-functional theory calculations, an interatomic Fe-H potential in the
Tersoff-Brenner formalism. The obtained analytical potential is suitable for
simulations of H in bulk Fe as well as for modeling small FeH molecules, and it
can be directly combined with our previously constructed potential for the
stainless steel Fe-Cr-C system. This will allow simulations of, e.g.,
hydrocarbon molecule chemistry on steel surfaces. In the current work, we apply
the potential to simulating hydrogen-induced embrittlement in monocrystalline
bulk Fe and in an Fe bicrystal with a grain boundary. In both cases, hydrogen
is found to soften the material.


title: Decomposing generalized bent and hyperbent functions

abstract:
  In this paper we introduce generalized hyperbent functions from $F_{2^n}$ to
$Z_{2^k}$, and investigate decompositions of generalized (hyper)bent functions.
We show that generalized (hyper)bent functions from $F_{2^n}$ to $Z_{2^k}$
consist of components which are generalized (hyper)bent functions from
$F_{2^n}$ to $Z_{2^{k^\prime}}$ for some $k^\prime < k$. For odd $n$, we show
that the Boolean functions associated to a generalized bent function form an
affine space of semibent functions. This complements a recent result for even
$n$, where the associated Boolean functions are bent.


title:
Preservation of a quantum Renyi relative entropy implies existence of a
  recovery map

abstract:
  It is known that a necessary and sufficient condition for equality in the
data processing inequality (DPI) for the quantum relative entropy is the
existence of a recovery map. We show that equality in DPI for a sandwiched
R\'enyi relative $\alpha$-entropy with $\alpha>1$ is also equivalent to this
property. For the proof, we use an interpolating family of $L_p$-norms with
respect to a state.


title:
Self-Triggered Control for Multi-Agent Systems with Quantized
  Communication or Sensing

abstract:
  The consensus problem for multi-agent systems with quantized communication or
sensing is considered. Centralized and distributed self-triggered rules are
proposed to reduce the overall need of communication and system updates. It is
proved that these self-triggered rules realize consensus exponentially if the
network topologies have a spanning tree and the quantization function is
uniform. Numerical simulations are provided to show the effectiveness of the
theoretical results.


title: On the Enumeration of all Minimal Triangulations

abstract:
  We present an algorithm that enumerates all the minimal triangulations of a
graph in incremental polynomial time. Consequently, we get an algorithm for
enumerating all the proper tree decompositions, in incremental polynomial time,
where "proper" means that the tree decomposition cannot be improved by removing
or splitting a bag.


title:
Scattering Equations, Twistor-string Formulas and Double-soft Limits in
  Four Dimensions

abstract:
  We study scattering equations and formulas for tree amplitudes of various
theories in four dimensions, in terms of spinor helicity variables and on-shell
superspace for supersymmetric theories. As originally obtained in Witten's
twistor string theory and other twistor-string models, the equations can take
either polynomial or rational forms, and we clarify the simple relation between
them. We present new, four-dimensional formulas for all tree amplitudes in the
non-linear sigma model, a special Galileon theory and the maximally
supersymmetric completion of the Dirac-Born-Infeld theory. Furthermore, we
apply the formulas to study various double-soft theorems in these theories,
including the emissions of a pair of soft photons, fermions and scalars for
super-amplitudes in super-DBI theory.


title:
Effects of Rayleigh waves on the essential spectrum in perturbed doubly
  periodic elliptic problems

abstract:
  We give an example of a scalar second order differential operator in the
plane with double periodic coefficients and describe its modification, which
causes an additional spectral band in the essential spectrum. The modified
operator is obtained by applying to the coefficients a mirror reflection with
respect to a vertical or horizontal line. This change gives rise to Rayleigh
type waves localized near the line. The results are proven using asymptotic
analysis, and they are based on high contrast of the coefficient functions.


title: Relativity of Quantum States and Observables

abstract:
  Under the principle that quantum mechanical observables are invariant under
relevant symmetry transformations, we explore how the usual, non-invariant
quantities may capture measurement statistics. Using a relativisation mapping,
viewed as the incorporation of a quantum reference frame, we show that the
usual quantum description approximates the relative one precisely when the
reference system admits an appropriate localisable quantity and a localised
state. From this follows a new perspective on the nature and reality of quantum
superpositions and optical coherence.


title: Field-induced superdiffusion and dynamical heterogeneity

abstract:
  By analyzing two Kinetically Constrained Models of supercooled liquids we
show that the anomalous transport of a driven tracer observed in supercooled
liquids is another facet of the phenomenon of dynamical heterogeneity. We focus
on the Fredrickson-Andersen and the Bertin-Bouchaud-Lequeux models. By
numerical simulations and analytical arguments we demonstrate that the
violation of the Stokes-Einstein relation and the observed field-induced
superdiffusion have the same physical origin: while a fraction of probes do not
move, others jump repeatedly because they are close to local mobile regions.
The anomalous fluctuations observed out of equilibrium in presence of a pulling
force $\epsilon$, $\sigma_x^2(t) = \langle x_\epsilon^2(t) \rangle - \langle
x_\epsilon(t) \rangle^2 \sim t^{3/2}$, which are accompanied by the asymptotic
decay $\alpha_\epsilon(t)\sim t^{-1/2}$ of the non-Gaussian parameter from
non-trivial values to zero, are due to the splitting of the probes population
in the two (mobile and immobile) groups and to dynamical correlations, a
mechanism expected to happen generically in supercooled liquids.


title: Cooperative Localization in WSNs: a Hybrid Convex/non-Convex Solution

abstract:
  We propose an efficient solution to peer-to-peer localization in a wireless
sensor network which works in two stages. At the first stage the optimization
problem is relaxed into a convex problem, given in the form recently proposed
by Soares, Xavier, and Gomes. The convex problem is efficiently solved in a
distributed way by an ADMM approach, which provides a significant improvement
in speed with respect to the original solution. In the second stage, a soft
transition to the original, non-convex, non relaxed formulation is applied in
such a way to force the solution towards a local minimum. The algorithm is
built in such a way to be fully distributed, and it is tested in meaningful
situations, showing its effectiveness in localization accuracy and speed of
convergence, as well as its inner robustness.


title:
Anomalous carrier density independent superconductivity in iron
  pnictides

abstract:
  Dome-shape superconductivity phase diagram can commonly be observed in
cuprate and iron-based systems via tuning parameters such as charge carrier
doping, pressure, bond angle, and etc. We report doping electrons from
transition-metal elements (TM = Co, Ni) substitution can induce high-Tc
superconductivity around 35 K in Ca0.94La0.06Fe2As2, which emerges abruptly
before the total suppression of the innate
spin-density-wave/anti-ferromagnetism (SDW/AFM) state. Unexpectedly, the onset
critical temperature for the high-Tc superconductivity stays constant for a
wide range of TM doping. Possible extrinsic factors like phase separation,
chemical inhomogeneity, and charge carrier cancelation effect are all excluded.
This anomalous charge carrier density independent SC is very similar to the
interface superconductivity in La2-xSrxCuO4-La2CuO4 bilayer system. The further
verified two-dimensional (2D) nature of superconductivity by the Tinkham's
angular-dependent critical field model as well as by the angle-resolved
magneto-resistance measurements jointly supports the idea of interfacial effect
induced high-Tc superconductivity.


title: Topological Hopf-Chern Insulators and the Hopf Superconductor

abstract:
  We introduce new three-dimensional topological phases of two-band models
using the Pontryagin-Thom construction. In symmetry class A these are the
infinitely many Hopf-Chern topological insulators, which are hybrids of layered
Chern insulators and the Hopf insulator. In symmetry class C, there is a
$\mathbb{Z}_2$-classification with the non-trivial topological phase, the Hopf
superconductor, being realized by a construction that doubles the usual Hopf
insulator in momentum space. For these new topological phases we investigate
the energy spectrum in the presence of a boundary and find gapless surface
modes, confirming the validity of the bulk-boundary correspondence.


title: Prospects of the Nambu Bracket

abstract:
  We review recent progress in formulating the worldvolume theory of M2-branes
using the Nambu bracket. Although it is generally agreed that this formulation
should be replaced by another using the superconformal Chern-Simons theory, we
try to pursue a possible complementary role played by the Nambu bracket. Since
the partition function of the superconformal Chern-Simons theory implies a
hidden super gauge group, we study the supersymmetric generalization of the
Nambu bracket. We explicitly construct the superunitary Nambu algebra.


title:
Discrete and continuum links to a nonlinear coupled transport problem of
  interacting populations

abstract:
  We are interested in exploring interacting particle systems that can be seen
as microscopic models for a particular structure of coupled transport flux
arising when different populations are jointly evolving. The scenarios we have
in mind are inspired by the dynamics of pedestrian flows in open spaces and are
intimately connected to cross-diffusion and thermo-diffusion problems holding a
variational structure. The tools we use include a suitable structure of the
relative entropy controlling TV-norms, the construction of Lyapunov functionals
and particular closed-form solutions to nonlinear transport equations, a
hydrodynamics limiting procedure due to Philipowski, as well as the
construction of numerical approximates to both the continuum limit problem in
2D and to the original interacting particle systems.


title: Method of Tibetan Person Knowledge Extraction

abstract:
  Person knowledge extraction is the foundation of the Tibetan knowledge graph
construction, which provides support for Tibetan question answering system,
information retrieval, information extraction and other researches, and
promotes national unity and social stability. This paper proposes a SVM and
template based approach to Tibetan person knowledge extraction. Through
constructing the training corpus, we build the templates based the shallow
parsing analysis of Tibetan syntactic, semantic features and verbs. Using the
training corpus, we design a hierarchical SVM classifier to realize the entity
knowledge extraction. Finally, experimental results prove the method has
greater improvement in Tibetan person knowledge extraction.


title: Breadth First Search Vectorization on the Intel Xeon Phi

abstract:
  Breadth First Search (BFS) is a building block for graph algorithms and has
recently been used for large scale analysis of information in a variety of
applications including social networks, graph databases and web searching. Due
to its importance, a number of different parallel programming models and
architectures have been exploited to optimize the BFS. However, due to the
irregular memory access patterns and the unstructured nature of the large
graphs, its efficient parallelization is a challenge. The Xeon Phi is a
massively parallel architecture available as an off-the-shelf accelerator,
which includes a powerful 512 bit vector unit with optimized scatter and gather
functions. Given its potential benefits, work related to graph traversing on
this architecture is an active area of research.
  We present a set of experiments in which we explore architectural features of
the Xeon Phi and how best to exploit them in a top-down BFS algorithm but the
techniques can be applied to the current state-of-the-art hybrid, top-down plus
bottom-up, algorithms.
  We focus on the exploitation of the vector unit by developing an improved
highly vectorized OpenMP parallel algorithm, using vector intrinsics, and
understanding the use of data alignment and prefetching. In addition, we
investigate the impact of hyperthreading and thread affinity on performance, a
topic that appears under researched in the literature. As a result, we achieve
what we believe is the fastest published top-down BFS algorithm on the version
of Xeon Phi used in our experiments. The vectorized BFS top-down source code
presented in this paper can be available on request as free-to-use software.


title: Chern-Mather classes of toric varieties

abstract:
  The purpose of this short note is to prove a formula for the Chern-Mather
classes of a toric variety in terms of its orbits and the local Euler
obstructions at general points of each orbit (Theorem 2). We use the general
definition of the Chern-Schwartz-MacPherson classes (see [7]) and their special
expression in case of a toric variety (see [2]). As a corollary, we obtain a
formula by Matsui-Takeuchi [8, Corollary 1.6]. Alternatively, one could deduce
the formula of Theorem 2 from the Matsui-Takeuchi formula, by using our general
result [11, Theoreme 3] for the degree of the polar varieties in terms of the
Chern-Mather classes.


title:
The space $\dot{\mathcal{B}}'$ of distributions vanishing at infinity -
  duals of tensor products

abstract:
  Analogous to L.~Schwartz' study of the space $\mathcal{D}'(\mathcal{E})$ of
semi-regular distributions we investigate the topological properties of the
space $\mathcal{D}'(\dot{\mathcal{B}})$ of semi-regular vanishing distributions
and give representations of its dual and of the scalar product with this dual.
In order to determine the dual of the space of semi-regular vanishing
distributions we generalize and modify a result of A. Grothendieck on the duals
of $E \hat\otimes F$ if $E$ and $F$ are quasi-complete and $F$ is not
necessarily semi-reflexive.


title: SymNet: scalable symbolic execution for modern networks

abstract:
  We present SymNet, a network static analysis tool based on symbolic
execution. SymNet quickly analyzes networks by injecting symbolic packets and
tracing their path through the network. Our key novelty is SEFL, a language we
designed for network processing that is symbolic-execution friendly.
  SymNet is easy to use: we have developed parsers that automatically generate
SEFL models from router and switch tables, firewall configurations and
arbitrary Click modular router configurations. Most of our models are exact and
have optimal branching factor. Finally, we built a testing tool that checks
SEFL models conform to the real implementation. SymNet can check networks
containing routers with hundreds of thousands of prefixes and NATs in seconds,
while ensuring packet header memory-safety and capturing network functionality
such as dynamic tunneling, stateful processing and encryption. We used SymNet
to debug middlebox interactions documented in the literature, to check our
department's network and the Stanford backbone network. Results show that
symbolic execution is fast and more accurate than existing static analysis
tools.


title:
An analysis of the pile-up of infinite periodic walls of edge
  dislocations

abstract:
  We analyse the equilibrium pile-up configurations of infinite periodic walls
of edge dislocations which are forced against an impenetrable obstacle by a
constant applied shear stress. Numerically generated density distributions
exhibit two distinct regions, for each of which we provide an interpretation
and an analytical prediction. Near the obstacle, the influence of neighbouring
slip planes may be neglected and the classical solution for a single slip plane
applies. At a larger distance a linear decay is obtained. The characteristic
length scales of the two parts of the pile-up are shown to depend differently
on the parameters of the problem.


title:
Multi time-step wave-front reconstruction for tomographic
  Adaptive-Optics systems

abstract:
  In tomographic adaptive-optics (AO) systems, errors due to tomographic
wave-front reconstruction limit the performance and angular size of the
scientific field of view (FoV), where AO correction is effective. We propose a
multi time-step tomographic wave-front reconstruction method to reduce the
tomographic error by using the measurements from both the current and the
previous time-steps simultaneously. We further outline the method to feed the
reconstructor with both wind speed and direction of each turbulence layer. An
end-to-end numerical simulation, assuming a multi-object AO (MOAO) system on a
30 m aperture telescope, shows that the multi time-step reconstruction
increases the Strehl ratio (SR) over a scientific FoV of 10 arcminutes in
diameter by a factor of 1.5--1.8 when compared to the classical tomographic
reconstructor, depending on the guide star asterism and with perfect knowledge
of wind speeds and directions. We also evaluate the multi time-step
reconstruction method and the wind estimation method on the RAVEN demonstrator
under laboratory setting conditions. The wind speeds and directions at multiple
atmospheric layers are measured successfully in the laboratory experiment by
our wind estimation method with errors below 2 \ms. With these wind estimates,
the multi time-step reconstructor increases the SR value by a factor of
1.2--1.5, which is consistent with a prediction from end-to-end numerical
simulation.


title:
Curvatures of left invariant Randers metric on the five-dimensional
  Heisenberg group

abstract:
  A left invariant Z-Randers metric on the five-dimensional Heisenberg group is
a left invariant Randers metric with deformation vector from the center of the
Heisenberg algebra. In this note we prove that for every left invariant
Z-Randers metric on the five-dimensional Heisenberg group there exist flags of
strictly negative and there exist flags of strictly positive curvatures.


title:
Invariant solutions to the Strominger system and the heterotic equations
  of motion

abstract:
  We construct many new invariant solutions to the Strominger system with
respect to a 2-parameter family of metric connections
$\nabla^{\varepsilon,\rho}$ in the anomaly cancellation equation. The ansatz
$\nabla^{\varepsilon,\rho}$ is a natural extension of the canonical 1-parameter
family of Hermitian connections found by Gauduchon, as one recovers the Chern
connection $\nabla^{c}$ for $({\varepsilon,\rho})=(0,\frac12)$, and the Bismut
connection $\nabla^{+}$ for $({\varepsilon,\rho})=(\frac12,0)$. In particular,
explicit invariant solutions to the Strominger system with respect to the Chern
connection, with non-flat instanton and positive $\alpha'$ are obtained.
Furthermore, we give invariant solutions to the heterotic equations of motion
with respect to the Bismut connection. Our solutions live on three different
compact non-K\"ahler homogeneous spaces, obtained as the quotient by a lattice
of maximal rank of a nilpotent Lie group, the semisimple group
SL(2,$\mathbb{C}$) and a solvable Lie group. To our knowledge, these are the
only known invariant solutions to the heterotic equations of motion, and we
conjecture that there is no other such homogeneous space admitting an invariant
solution to the heterotic equations of motion with respect to a connection in
the ansatz $\nabla^{\varepsilon,\rho}$.


title: Full-Duplex Cellular Networks: It Works!

abstract:
  Full-duplex (FD) communications with bidirectional transmitting and receiving
at the same time and frequency radio resource have long been deemed a promising
way to boost spectrum efficiency, but hindered by the techniques for
self-interference cancellation (SIC). Recent breakthroughs in analog and
digital signal processing yield the feasibility of beyond $100$ dB SIC
capability and make it possible for FD communications to demonstrate nearly
doubled spectrum efficiency for point-to-point links. Now it is time to shift
at least partial of our focus to full duplex networking, such as in cellular
networks, since it is not straightforward but demanding novel and more
complicated interference management techniques. Before putting FD networking
into practice, we need to understand that what scenarios FD communications
should be applied in under the current technology maturity, how bad the
performance will be if we do nothing to deal with the newly introduced
interference, and most importantly, how much improvement could be achieved
after applying advanced solutions. This article will shed light on these
questions.


title:
Flavour dependence of the pion and kaon form factors and parton
  distribution functions

abstract:
  The separate quark flavour contributions to the pion and kaon valence quark
distribution functions are studied, along with the corresponding
electromagnetic form factors in the space-like region. The calculations are
made using the solution of the Bethe-Salpeter equation for the model of Nambu
and Jona-Lasinio with proper-time regularization. Both the pion and kaon form
factors and the valence quark distribution functions reproduce many of the
features of the available empirical data. The larger mass if the strange quark
naturally explains the empirical fact that the ratio $u_{K^+}(x)/u_{\pi^+}(x)$
drops below unity at large $x$, with a value of approximately $M^2_u/M_s^2$ as
$x \to 1$. With regard to the elastic form factors we report a large flavour
dependence, with the $u$-quark contribution to the kaon form factor being an
order of magnitude smaller than that of the $s$-quark at large $Q^2$, which may
be a sensitive measure of confinement effects in QCD. Surprisingly though, the
total $K^+$ and $\pi^+$ form factors differ by only 10\%.


title: Preferential Gas Adsorption at the Graphene-Water interface

abstract:
  The contact of water with graphene is of fundamental importance and of great
interest for numerous promising applications, but how graphene interacts with
water remains unclear. Here we used atomic force microscopy to investigate
hydrophilic mica substrates with some regions covered by mechanically
exfoliated graphene layers in water. In water containing air gas close to the
saturation concentration (within ~40%), cap-shaped nanostructures and ordered
stripe domains were observed on graphene-covered regions, but not on pure mica
regions. These structures did not appear on graphene when samples were immersed
in highly degassed water, indicating that their formation was caused by
adsorption of gas dissolved in water. Thus, atomically thin graphene, even at a
narrow width of 20 nm, changes the local surface chemistry of a highly
hydrophilic substrate. Further, surface hydrophobicity significantly affects
gas adsorption, which has broad implications for diverse phenomena in water.


title:
Active Learning for Online Recognition of Human Activities from
  Streaming Videos

abstract:
  Recognising human activities from streaming videos poses unique challenges to
learning algorithms: predictive models need to be scalable, incrementally
trainable, and must remain bounded in size even when the data stream is
arbitrarily long. Furthermore, as parameter tuning is problematic in a
streaming setting, suitable approaches should be parameterless, and make no
assumptions on what class labels may occur in the stream. We present here an
approach to the recognition of human actions from streaming data which meets
all these requirements by: (1) incrementally learning a model which adaptively
covers the feature space with simple local classifiers; (2) employing an active
learning strategy to reduce annotation requests; (3) achieving promising
accuracy within a fixed model size. Extensive experiments on standard
benchmarks show that our approach is competitive with state-of-the-art
non-incremental methods, and outperforms the existing active incremental
baselines.


title:
Non radial type II blow up for the energy supercritical semilinear heat
  equation

abstract:
  We consider the semilinear heat equation in large dimension $d\geq 11$ $$
\partial_t u =\Delta u+|u| ^{p-1}u, \ \ p=2q+1, \ \ q\in \mathbb N $$ on a
smooth bounded domain $\Omega\subset \mathbb R^d$ with Dirichlet boundary
condition. In the supercritical range $p\geq p(d)>1+\frac{4}{d-2}$ we prove the
existence of a countable family $(u_\ell)_{\ell \in \mathbb N}$ of solutions
blowing-up at time $T>0$ with type II blow up: $$ \parallel u_{\ell}(t)
\parallel_{L^{\infty}} \sim C (T-t)^{-c_\ell} $$ with blow-up speed
$c_\ell>\frac{1}{p-1}$. They concentrate the ground state $Q$ being the only
radially and decaying solution of $\Delta Q+Q^p=0$: $$ u(x,t)\sim
\frac{1}{\lambda (t)^{\frac{2}{p-1}}}Q\left(\frac{x-x_0}{\lambda (t)} \right),
\ \lambda\sim C(u_n)(T-t)^{\frac{c_\ell(p-1)}{2}} $$ at some point $x_0\in
\Omega$. The result generalizes previous works on the existence of type II
blow-up solutions, which only existed in the radial setting. The present proof
uses robust nonlinear analysis tools instead, based on energy methods and
modulation techniques. This is the first non-radial construction of a solution
blowing up by concentration of a stationary state in the supercritical regime,
and provides a general strategy to prove similar results for dispersive
equations or parabolic systems and to extend it to multiple blow ups.


title: Wormholes, the weak energy condition, and scalar-tensor gravity

abstract:
  We obtain a large class of Lorentzian wormhole spacetimes in scalar-tensor
gravity, for which the matter stress energy does satisfy the weak energy
condition. Our constructions have zero Ricci scalar and an everywhere finite,
non-zero scalar field profile. Interpreting the scalar-tensor gravity as an
effective on-brane theory resulting from a two-brane Randall--Sundrum model of
warped extra dimensions, it is possible to link wormhole existence with that of
extra dimensions. We study the geometry, matter content, gravitational
red-shift and circular orbits in such wormholes and argue that our examples are
perhaps among those which may have some observational relevance in astrophysics
in future. We also study traversability and find that our wormholes are indeed
traversable for values of the metric parameters satisfying the weak energy
condition.


title:
Microstructural topology effects on the onset of ductile failure in
  multi-phase materials - a systematic computational approach

abstract:
  Multi-phase materials are key for modern engineering applications. They are
generally characterized by a high strength and ductility. Many of these
materials fail by ductile fracture of the, generally softer, matrix phase. In
this work we systematically study the influence of the arrangement of the
phases by correlating the microstructure of a two-phase material to the onset
of ductile failure. A single topological feature is identified in which
critical levels of damage are consistently indicated. It consists of a small
region of the matrix phase with particles of the hard phase on both sides in a
direction that depends on the applied deformation. Due to this configuration, a
large tensile hydrostatic stress and plastic strain is observed inside the
matrix, indicating high damage. This topological feature has, to some extent,
been recognized before for certain multi-phase materials. This study however
provides insight in the mechanics involved, including the influence of the
loading conditions and the arrangement of the phases in the material
surrounding the feature. Furthermore, a parameter study is performed to explore
the influence of volume fraction and hardness of the inclusion phase. For the
same macroscopic hardening response, the ductility is predicted to increase if
the volume fraction of the hard phase increases while at the same time its
hardness decreases.


title:
On the structure of the two-stream instability -- complex G-Hamiltonian
  structure and Krein collisions between positive- and negative-action modes

abstract:
  The two-stream instability is probably the most important elementary example
of collective instabilities in plasma physics and beam-plasma systems. For a
warm plasma with two charged particle species based on a 1D warm-fluid model,
the instability diagram of the two-stream instability exhibits an interesting
band structure that has not been explained. We show that the band structure for
this instability is the consequence of the Hamiltonian nature of the warm
two-fluid system. Interestingly, the Hamiltonian nature manifests as a complex
G-Hamiltonian structure in wave-number space, which directly determines the
instability diagram. Specifically, it is shown that the boundaries between the
stable and unstable regions are locations for Krein collisions between
eigenmodes with different Krein signatures. In terms of physics, this
rigorously implies that the system is destabilized when a positive-action mode
resonates with a negative-action mode, and that this is the only mechanism by
which the system can be destabilized. It is anticipated that this physical
mechanism of destabilization is valid for other collective instabilities in
conservative systems in plasma physics, accelerator physics, and fluid dynamics
systems, which admit infinite-dimensional Hamiltonian structures.


title: Some extensions to the functional analytic approach to Colombeau algebra

abstract:
  We extend the functional analytic approach to Colombeau-type spaces of
nonlinear generalized functions in order to study algebras of tempered
generalized functions. We obtain a definition of Fourier transform of nonlinear
generalized functions which has a strict inversion theorem, agrees with the
classical Fourier transform for tempered distributions and preserves well-known
classical properties.


title:
Linear response theory for electron-hole pair kinetics: exciton
  formation

abstract:
  A linear response theory for electron-hole pair density is developed, which
constitutes a new theoretical method, and a definition of exciton density in a
first-principles context is derived by considering both the electron-hole
attractive interaction and the screening effect. This allows the exciton time
evolution to be examined. This formulation is applied to a jellium model in
order to prove the existence of a transient exciton, and to observe crossover
from a transient to a stable exciton in response to decreased electron density.
The exciton formation mechanism is also revealed.


title: Star operations on numerical semigroups: antichains and explicit results

abstract:
  We introduce an order on the set of non-divisorial ideals of a numerical
semigroup $S$, and link antichains of this order with the star operations on
$S$; subsequently, we use this order to find estimates on the number of star
operations on $S$. We then use them to find an asymptotic estimate on the
number of nonsymmetric numerical semigroups with $n$ or less star operations,
and to determine these semigroups explicitly when $n=10$.


abstract:
  In this paper, the Hom-Lie superalgebra structures on exceptional simple Lie
superalgebras of vector fields are studied. Taking advantage of the Z-grading
structures and the transitivity, we prove that there is only the trivial
Hom-Lie superalgebra structures on exceptional simple Lie superalgebras. Our
proof is obtained by studying the Hom-Lie superalgebra structures on their 0-th
and -1-st Z-components.


title:
Stokes vector and its relationship to Discrete Wigner Functions of
  multiphoton states

abstract:
  Stokes vectors and Discrete Wigner functions (DWF) provide two alternate ways
of representing the polarization state of multiphoton systems. The Stokes
vector associated with a n-photon polarization state is unique, and its
Minkowski squared norm provides a direct way of quantifying entanglement
through n-concurrence. However, the quantification of entanglement from DWF is
not straight forward. The DWF associated with a given quantum state is not
unique but depends on the way in which basis vectors are assigned to various
lines in the phase space. For a Hilbert space of dimension N, there exists N
N+1 such possible assignments. While a given DWF corresponds to a unique Stokes
vector, the converse is not true. In the present work, we show that, for each
particular assignment called a quantum net, there exist a unique Hadamard
matrix which relates the Stokes vector to the corresponding DWF. This method
provides an elegant and direct method of constructing the DWFs from the Stokes
vector for every possible choice of the quantum net. Using these results, we
derive the relationship between the Stokes vector of a spin-flipped state and
the DWF. Finally, we also present a method to express the Minkowskian squared
norm of the Stokes vector directly in terms of the DWF.


title: Spectrum and genus of commuting graphs of some classes of finite rings

abstract:
  The commuting graph of a non-commutative ring $R$ with center $Z(R)$ is a
simple undirected graph whose vertex set is $R\setminus Z(R)$ and two vertices
$x, y$ are adjacent if and only if $xy = yx$. In this paper, we compute the
spectrum and genus of commuting graphs of some classes of finite rings.


title: Dynamical Evolution of Primordial Dark Matter Haloes through Mergers

abstract:
  Primordial dark matter (DM) haloes are the smallest gravitationally bound DM
structures from which the first stars, black holes, and galaxies form and grow
in the early universe. However, their structures are sensitive to the free
streaming scale of DM, which in turn depends on the nature of DM particles. In
this work, we test the hypothesis that the slope of the central cusps in
primordial DM haloes near the free streaming scale depends on the nature of
merging process. By combining and analysing data from a cosmological simulation
with the cutoff in the small-scale matter power spectrum as well as a suite of
controlled, high-resolution simulations of binary mergers, we find that (1) the
primordial DM haloes form preferentially through major mergers in radial
orbits; (2) their central DM density profile is more susceptible to a merging
process compared to that of galaxy and cluster-size DM haloes; (3) consecutive
major mergers drive the central density slope to approach the {\it universal}
form characterized by the NFW profile, which is shown to be robust to the
impacts of mergers and serves an attractor solution for the density structure
of DM haloes. Our work highlights the importance of dynamical processes on the
structure formation during the Dark Ages.


title:
Magnetic Field Driven Nodal Topological Superconductivity in Monolayer
  Transition Metal Dichalcogenides

abstract:
  Recently, Ising superconductors which possess in-plane upper critical fields
much larger than the Pauli limit field are under intense experimental study.
Many monolayer or few layer transition metal dichalcogenides are shown to be
Ising superconductors. In this work, we show that in a wide range of
experimentally accessible regimes where the in-plane magnetic field is higher
than the Pauli limit field but lower than $H_{c2}$, a 2H-structure monolayer
NbSe$_2$ or simiarly TaS$_2$ becomes a nodal topological superconductor. The
bulk nodal points appear on the $\Gamma- M$ lines of the Brillouin zone where
the Ising SOC vanishes. The nodal points are connected by Majorana flat bands,
similar to the Weyl points being connected by surface Fermi arcs in Weyl
semimetals. The Majorana flat bands are associated with a large number of zero
energy Majorana fermion edge modes which induce spin-triplet Cooper pairs. This
work demonstrates an experimentally feasible way to realise Majorana fermions
in nodal topological superconductor, without any fining tuning of experimental
parameters.


title:
A computationally assisted spectroscopic technique to measure secondary
  electron emission coefficients in radio frequency plasmas

abstract:
  A Computationally Assisted Spectroscopic Technique to measure secondary
electron emission coefficients ($\gamma$-CAST) in capacitively-coupled
radio-frequency plasmas is proposed. This non-intrusive, sensitive diagnostic
is based on a combination of Phase Resolved Optical Emission Spectroscopy and
particle-based kinetic simulations. In such plasmas (under most conditions in
electropositive gases) the spatio-temporally resolved electron-impact
excitation/ionization rate features two distinct maxima adjacent to each
electrode at different times within each RF period. While one maximum is the
consequence of the energy gain of electrons due to sheath expansion, the second
maximum is produced by secondary electrons accelerated towards the plasma bulk
by the sheath electric field at the time of maximum voltage drop across the
adjacent sheath. Due to these different excitation/ionization mechanisms, the
ratio of the intensities of these maxima is very sensitive to the secondary
electron emission coefficient $\gamma$. This sensitvity, in turn, allows
$\gamma$ to be determined by comparing experimental excitation profiles and
simulation data obtained with various $\gamma$-coefficients. The diagnostic,
tested here in a geometrically symmetric argon discharge, yields an effective
secondary electron emission coefficient of $\gamma = 0.066 \pm 0.01$ for
stainless steel electrodes.


title:
Evaluation of Disorder Introduced by Electrolyte Gating through
  Transport Measurements in Graphene

abstract:
  We evaluate the degree of disorder in electrolyte gating devices through the
transport measurements in graphene. By comparing the mobility in ion- and
standard metal-gated devices, we show that the deposition of the ionic liquid
introduces charged impurities with a density of approximately $6\times 10^{12}$
cm$^{-2}$; setting the upper limit of the mobility in graphene to 3000
cm$^2$/Vs. At higher temperature, phonons in the ionic liquid further reduce
the mobility, making its upper limit 2000 cm$^2$/Vs at room temperature. Since
the degree of disorder is independent of the base material, these results are
valuable towards understanding disorder effects in general devices using
electrolyte gating.


title: Counting triangulations of some classes of subdivided convex polygons

abstract:
  We compute the number of triangulations of a convex $k$-gon each of whose
sides is subdivided by $r-1$ points. We find explicit formulas and generating
functions, and we determine the asymptotic behaviour of these numbers as $k$
and/or $r$ tend to infinity. We connect these results with the question of
finding the planar set of points in general position that has the minimum
possible number of triangulations - a well-known open problem from
computational geometry.


title: Approximation properties of local smoothing kernels

abstract:
  We study some properties of smoothing kernels and their local expression as
they appear in the construction of Colombeau-type generalized function algebras
which are diffeomorphism invariant.


title: Is this scaling nonlinear?

abstract:
  One of the most celebrated findings in complex systems in the last decade is
that different indexes y (e.g., patents) scale nonlinearly with the
population~x of the cities in which they appear, i.e., $y\sim x^\beta, \beta
\neq 1$. More recently, the generality of this finding has been questioned in
studies using new databases and different definitions of city boundaries. In
this paper we investigate the existence of nonlinear scaling using a
probabilistic framework in which fluctuations are accounted explicitly. In
particular, we show that this allows not only to (a) estimate $\beta$ and
confidence intervals, but also to (b) quantify the evidence in favor of $\beta
\neq 1$ and (c) test the hypothesis that the observations are compatible with
the nonlinear scaling. We employ this framework to compare $5$ different models
to $15$ different datasets and we find that the answers to points (a)-(c)
crucially depend on the fluctuations contained in the data, on how they are
modeled, and on the fact that the city sizes are heavy-tailed distributed.


title:
Nanoscale heterogeneous phase separation kinetics in binary mixtures:
  Multistage dynamics

abstract:
  In order to find a measure of the dynamical features of phase separation
kinetics during spinodal decomposition of a liquid binary mixture (like water
and cyclohexane , water and 2,6 lutidiene or methanol and cyclohexane), we
study both the initial fast exponential-like growth (the Cahn-Hilliard regime)
and the subsequent cross-over to a much slower, non-exponential long time
growth (the so-called scaling regime), by atomistic molecular dynamics (MD)
simulation of a structure breaking binary liquid mixture. In particular, we
combine our MD simulations with a coarse grained multi scale modelling (CGMSM)
capable of capturing both length and time scales of phase separation kinetics
within simulation box. The system is quenched from a higher temperature to two
lower temperatures well below the coexistence temperature of the phase diagram.
We observe a multiscale phase separation dynamics. Initially the growth is
exponential up to a regime of 80-100ps having strong dependence over quench
depth. Subsequently a cross-over regime appears where the dynamics slows down
considerably due to coarsening through a power law phase. For deeper quench
power law growth dominates over the initial exponential and the cross-over
becomes transient. We find that for the present parameter values for the binary
mixture, the initial rapid growth of structure formation is practically over
within 200 ps which is followed by slow structural coarsening. When scaled by
the respective viscosities, this time translates to 50-200 ns for
water-lutidine binary mixture. The last part of dynamics may extend into ms.
The dynamics of phase separation is slowest in regions that have equitable
distribution of the two species, and one can observe the signatures of "up-hill
diffusion" that is a trade mark of spinodal decomposition.


title:
On the red giant branch mass loss in 47 Tucanae: Constraints from the
  horizontal branch morphology

abstract:
  We obtain stringent constraints on the actual efficiency of mass loss for red
giant branch stars in the Galactic globular cluster 47 Tuc, by comparing
synthetic modeling based on stellar evolution tracks with the observed
distribution of stars along the horizontal branch in the
colour-magnitude-diagram. We confirm that the observed, wedge-shaped
distribution of the horizontal branch can be reproduced only by accounting for
a range of initial He abundances --in agreement with inferences from the
analysis of the main sequence-- and a red giant branch mass loss with a small
dispersion. We have carefully investigated several possible sources of
uncertainty that could affect the results of the horizontal branch modeling,
stemming from uncertainties in both stellar model computations and the cluster
properties such as heavy element abundances, reddening and age. We determine a
firm lower limit of ~0.17$Mo for the mass lost by red giant branch stars,
corresponding to horizontal branch stellar masses between ~0.65Mo and ~0.73Mo
(the range driven by the range of initial helium abundances). We also derive
that in this cluster the amount of mass lost along the asymptotic giant branch
stars is comparable to the mass lost during the previous red giant branch
phase. These results confirm for this cluster the disagreement between
colour-magnitude-diagram analyses and inferences from recent studies of the
dynamics of the cluster stars, that predict a much less efficient red giant
branch mass loss. A comparison between the results from these two techniques
applied to other clusters is required, to gain more insights about the origin
of this disagreement.


title:
Construction of Arakelov-modular Lattices over Totally Definite
  Quaternion Algebras

abstract:
  We study ideal lattices constructed from totally definite quaternion algebras
over totally real number fields, and generalize the definition of
Arakelov-modular lattices over number fields. In particular, we prove for the
case where the totally real number field is $\mathbb{Q}$, that for $\ell$ a
prime integer, there always exists a totally definite quaternion over
$\mathbb{Q}$ from which an Arakelov-modular lattice of level $\ell$ can be
constructed.


title:
Shot noise generated by graphene p-n junctions in the quantum Hall
  effect regime

abstract:
  Owing to a linear and gapless band structure and a tunability of the charge
carrier type, graphene offers a unique system to investigate transport of Dirac
Fermions at p-n junctions (PNJs). In a magnetic field, combination of quantum
Hall physics and the characteristic transport across PNJs leads to a
fractionally quantized conductance associated with the mixing of electron-like
and hole-like modes and their subsequent partitioning. The mixing and
partitioning suggest that a PNJ could be used as an electronic beam-splitter.
Here we report the shot noise study of the mode mixing process and demonstrate
the crucial role of the PNJ length. For short PNJs, the amplitude of the noise
is consistent with an electronic beam-splitter behavior, whereas, for longer
PNJs, it is reduced by the energy relaxation. Remarkably, the relaxation length
is much larger than typical size of mesoscopic devices, encouraging using
graphene for electron quantum optics and quantum information processing.