title: Quantum information inequalities via tracial positive linear maps

abstract:
  We present some generalizations of quantum information inequalities involving
tracial positive linear maps between $C^*$-algebras. Among several results, we
establish a noncommutative Heisenberg uncertainty relation. More precisely, we
show that if $\Phi: \mathcal{A} \to \mathcal{B}$ is a tracial positive linear
map between $C^*$-algebras , $\rho \in \mathcal{A}$ is a $\Phi$-density element
and $A,B$ are self-adjoint operators of $\mathcal{A}$ such that $ {\rm
sp}(\mbox{-i}\rho^\frac{1}{2}[A,B]\rho^\frac{1}{2}) \subseteq [m,M] $ for some
scalers $0<m<M$, then under some conditions \begin{eqnarray}\label{inemain1}
V_{\rho,\Phi}(A)\sharp V_{\rho,\Phi}(B)\geq
\frac{1}{2\sqrt{K_{m,M}(\rho[A,B])}} \left|\Phi(\rho [A,B])\right|,
\end{eqnarray} where $K_{m,M}(\rho[A,B])$ is the Kantorovich constant of the
operator $\mbox{-i}\rho^\frac{1}{2}[A,B]\rho^\frac{1}{2}$ and
$V_{\rho,\Phi}(X)$ is the generalized variance of $X$.\\ In addition, we use
some arguments differing from the scalar theory to present some inequalities
related to the generalized correlation and the generalized
Wigner--Yanase--Dyson skew information.

categories: math.FA cs.IT math-ph math.IT math.MP math.OA


title:
Modeling sexual selection in T\'ungara frog and rationality of mate
  choice

abstract:
  The males of the specie of frogs Engystomops pustulosus produce simple and
com- plex calls to lure females, as a way of Intersexual selection. Complex
calls lead males to a greater reproductive success than simple calls do.
However, the complex calls are also more attractive to the main predator of
these amphibians, the bat Trachops cirrhosus. Therefore, as M. Ryan suggests,
the complexity of the calls let the frogs keep a trade off between reproductive
success and predation. In this paper, we first propose to model the proportion
of simple to complex calls as a symmetric game of two strategies. We also
propose a model with three strategies (simple callers, complex callers and
quiet males), where we assess the effect of a male that keeps quiet and
intercepts females, which would play a role of Intrasexual selection. We
analyze the stable points of the replicator equations of the models that we
propose. Under the assumption that the decision of the males takes into account
this trade off between reproductive success and predation, our model reproduces
the observed behavior reported in the literature with minimal assumption on the
parameters. From the three strategies model, we verify that the quiet strategy
could only coexists with the simple and complex strategies as long as the rate
at which quiet males intercept females is high. We conclude that the
reproductive strategy of the male frog Engystomops pustulosus is rational.


title: Blowup algebras of rational normal scrolls

abstract:
  We determine the equations of the blowup of $\mathbb{P}^n$ along a $d$-fold
rational normal scroll $S$, and we prove that the Rees ring and special fiber
ring of $S \subseteq \mathbb{P}^n$ are Koszul algebras.


title:
The Curvature-Augmented Closest Point Method with Vesicle
  Inextensibility Application

abstract:
  The Closest Point method, initially developed by Ruuth and Merriman, allows
for the numerical solution of surface partial differential equations without
the need for a parameterization of the surface itself. Surface quantities are
embedded into the surrounding domain by assigning each value at a given spatial
location to the corresponding value at the closest point on the surface. This
embedding allows for surface derivatives to be replaced by their Cartesian
counterparts (e.g. $\nabla_s = \nabla$). This equivalence is only valid on the
surface, and thus, interpolation is used to enforce what is known as the side
condition away from the surface. To improve upon the method, this work derives
an operator embedding that incorporates curvature information, making it valid
in a neighborhood of the surface. With this, direct enforcement of the side
condition is no longer needed. Comparisons in $\mathbb{R}^2$ and $\mathbb{R}^3$
show that the resulting Curvature-Augmented Closest Point method has better
accuracy and requires less memory, through increased matrix sparsity, than the
Closest Point method, while maintaining similar matrix condition numbers. To
demonstrate the utility of the method in a physical application, simulations of
inextensible, bi-lipid vesicles evolving toward equilibrium shapes are also
included.


title: String Homology and Lie Algebra Structures (Ph.D. Thesis)

abstract:
  Chas and Sullivan introduced string homology, which is the equivariant
homology of the loop space with the $S^1$ action on loops by rotation. Craig
Westerland computed the string homology for spheres with coefficients in
$\mathbb{Z} /2\mathbb{Z}$, and in Somnath Basu's dissertation, he computes the
string homology and string bracket for spheres over rational coefficients, and
he finds that the bracket is trivial. In this paper, we compute string homology
and the string bracket for spheres with integer coefficients, treating the odd-
and even-dimensional cases separately. We use the Gysin sequence and
Leray-Serre spectral sequence to aid in our computations. We find that over the
integers, the string Lie algebra bracket structure is more interesting, and not
always zero. The string bracket turns out to be non-zero on torsion coming from
string homology. We also make some computations of the Goldman Lie algebra
structure, and more generally, the string Lie algebra structure of closed,
orientable surfaces.


title: A Survey of Voice Translation Methodologies - Acoustic Dialect Decoder

abstract:
  Speech Translation has always been about giving source text or audio input
and waiting for system to give translated output in desired form. In this
paper, we present the Acoustic Dialect Decoder (ADD) - a voice to voice
ear-piece translation device. We introduce and survey the recent advances made
in the field of Speech Engineering, to employ in the ADD, particularly focusing
on the three major processing steps of Recognition, Translation and Synthesis.
We tackle the problem of machine understanding of natural language by designing
a recognition unit for source audio to text, a translation unit for source
language text to target language text, and a synthesis unit for target language
text to target language speech. Speech from the surroundings will be recorded
by the recognition unit present on the ear-piece and translation will start as
soon as one sentence is successfully read. This way, we hope to give translated
output as and when input is being read. The recognition unit will use Hidden
Markov Models (HMMs) Based Tool-Kit (HTK), hybrid RNN systems with gated memory
cells, and the synthesis unit, HMM based speech synthesis system HTS. This
system will initially be built as an English to Tamil translation device.


title: Optimizing Epistemic Model Checking using Conditional Independence

abstract:
  Conditional independence reasoning has been shown to be helpful in the
context of Bayesian nets to optimize probabilistic inference, and related
techniques have been applied to speed up a number of logical reasoning tasks in
boolean logic by eliminating irrelevant parts of the formulas. This paper shows
that conditional independence reasoning can also be applied to optimize
epistemic model checking, in which one verifies that a model for a number of
agents operating with imperfect information satisfies a formula expressed in a
modal multi-agent logic of knowledge. An optimization technique is developed
that precedes the use of a model checking algorithm with an analysis that
applies conditional independence reasoning to reduce the size of the model. The
optimization has been implemented in the epistemic model checker MCK. The paper
reports experimental results demonstrating that it can yield multiple orders of
magnitude performance improvements.


title: A framework for analyzing contagion in assortative banking networks

abstract:
  We introduce a probabilistic framework that represents stylized banking
networks with the aim of predicting the size of contagion events. Most previous
work on random financial networks assumes independent connections between
banks, whereas our framework explicitly allows for (dis)assortative edge
probabilities (e.g., a tendency for small banks to link to large banks). We
analyze default cascades triggered by shocking the network and find that the
cascade can be understood as an explicit iterated mapping on a set of edge
probabilities that converges to a fixed point. We derive a cascade condition
that characterizes whether or not an infinitesimal shock to the network can
grow to a finite size cascade, in analogy to the basic reproduction number
$R_0$ in epidemic modelling. The cascade condition provides an easily computed
measure of the systemic risk inherent in a given banking network topology.
Using the percolation theory for random networks we also derive an analytic
formula for the frequency of global cascades. Although the analytical methods
are derived for infinite networks, we demonstrate using Monte Carlo simulations
the applicability of the results to finite-sized networks. We show that
edge-assortativity, the propensity of nodes to connect to similar nodes, can
have a strong effect on the level of systemic risk as measured by the cascade
condition. However, the effect of assortativity on systemic risk is subtle, and
we propose a simple graph theoretic quantity, which we call the
graph-assortativity coefficient, that can be used to assess systemic risk.

categories: physics.soc-ph cond-mat.stat-mech cs.SI q-fin.GN


title: Virtual 1-domination of 3-manifolds

abstract:
  It is shown in this paper that given any closed oriented hyperbolic
3-manifold, every closed oriented 3-manifold is mapped onto by a finite cover
of that manifold via a map of degree 1, or in other words, virtually
1-dominated by that manifold. This improves a known result of virtual
2-domination. The proof invokes a recently developed enhanced version of the
connection principle in good pants constructions.


title: A Note on Model Selection for Small Sample Regression

abstract:
  The risk estimator called "Direct Eigenvalue Estimator" (DEE) is studied. DEE
was developed for small sample regression. In contrast to many existing model
selection criteria, derivation of DEE requires neither any asymptotic
assumption nor any prior knowledge about the noise variance and the noise
distribution. It was reported that DEE performed well in small sample cases but
DEE performed a little worse than the state-of-the-art ADJ. This seems somewhat
counter-intuitive because DEE was developed for specifically regression problem
by exploiting available information exhaustively, while ADJ was developed for
general setting. In this paper, we point out that the derivation of DEE
includes an inappropriate part in spite that the resultant form of DEE is valid
in a sense. As its result, DEE cannot derive its potential. We introduce a
class of valid risk estimators based on the idea of DEE and show that better
risk estimators (mDEE) can be found in the class. By numerical experiments, we
verify that mDEE often performs better than or at least equally the original
DEE and ADJ.


title: Continuous-Time, Discrete-Event Simulation from Counting Processes

abstract:
  This is a method for discrete event simulation specified by survival
analysis. It presents a sequence of steps. First, hazard rates from survival
analysis specify the rates of a set of counting processes. Second, those
counting processes define a transition kernel. Third, there are four different
ways to sample that transition kernel, including a first-principles derivation
of exact stochastic simulation algorithms (SSA) in continuous time. This
simulation allows time-dependent intensities which include both continuous and
atomic components. Separating the steps involved makes a clear correspondence
between mathematical formulation and algorithmic implementation.


title:
The effect of rotation on oscillatory double-diffusive convection
  (semiconvection)

abstract:
  Oscillatory double-diffusive convection (ODDC, more traditionally called
semiconvection) is a form of linear double-diffusive instability that occurs in
fluids that are unstably stratified in temperature (Schwarzschild unstable),
but stably stratified in chemical composition (Ledoux stable). This scenario is
thought to be quite common in the interiors of stars and giant planets, and
understanding the transport of heat and chemical species by ODDC is of great
importance to stellar and planetary evolution models. Fluids unstable to ODDC
have a tendency to form convective thermo-compositional layers which
significantly enhance the fluxes of temperature and chemical composition
compared with microscopic diffusion. Although a number of recent studies have
focused on studying properties of both layered and non-layered ODDC, few have
addressed how additional physical processes such as global rotation affect its
dynamics. In this work we study first how rotation affects the linear stability
properties of rotating ODDC. Using direct numerical simulations we then analyze
the effect of rotation on properties of layered and non-layered ODDC, and study
how the angle of the rotation axis with respect to the direction of gravity
affects layering. We find that rotating systems can be broadly grouped into two
categories, based on the strength of rotation. Qualitative behavior in the more
weakly rotating group is similar to non-rotating ODDC, but strongly rotating
systems become dominated by vortices that are invariant in the direction of the
rotation vector and strongly influence transport. We find that whenever layers
form, rotation always acts to reduce thermal and compositional transport.


title: Replica Symmetry Breaking without Replicas

abstract:
  We introduce a mathematical framework based on simple combinatorial arguments
(Kernel Representation) that allows to deal successfully with spin glass
problems, among others. Let $\Omega^{N}$ be the space of configurations of an
$N-$ spins system, each spin having a finite set $\Omega$ of inner states, and
let $\mu:\Omega^{N}\rightarrow\left[0,1\right]$ be some probability measure.
Here we give an argument to encode $\mu$ into a kernel function
$M:\left[0,1\right]^{2}\rightarrow\Omega$, and use this notion to reinterpret
the assumptions of the Replica Symmetry Breaking ansatz (RSB) of Parisi et Al.
[1, 2], without using replicas, nor averaging on the disorder.


title: Discovery of a Hot Corino in the Bok Globule B335

abstract:
  We report the first evidence of a hot corino in a Bok globule. This is based
on the ALMA observations in the 1.2 mm band toward the low-mass Class 0
protostar IRAS 19347+0727 in B335. Saturated complex organic molecules (COMs),
CH$_3$CHO, HCOOCH$_3$, and NH$_2$CHO, are detected in a compact region within a
few 10 au around the protostar. Additionally, CH$_3$OCH$_3$, C$_2$H$_5$OH,
C$_2$H$_5$CN, and CH$_3$COCH$_3$ are tentatively detected. Carbon-chain related
molecules, CCH and c-C$_3$H$_2$, are also found in this source, whose
distributions are extended over a few 100 au scale. On the other hand,
sulfur-bearing molecules CS, SO, and SO$_2$, have both compact and extended
components. Fractional abundances of the COMs relative to H$_2$ are found to be
comparable to those in known hot-corino sources. Though the COMs lines are as
broad as 5-8 km s$^{-1}$, they do not show obvious rotation motion in the
present observation. Thus, the COMs mainly exist in a structure whose
distribution is much smaller than the synthesized beam (0."58 x 0."52).


title: Contact Surgeries on the Legendrian Figure-Eight Knot

abstract:
  We show that all positive contact surgeries on every Legendrian figure-eight
knot in $(S^3, \xi_{\rm{std}})$ result in an overtwisted contact structure. The
proof uses convex surface theory and invariants from Heegaard Floer homology.


title: Rank Verification for Exponential Families

abstract:
  Many statistical experiments involve comparing multiple population groups.
For example, a public opinion poll may ask which of several political
candidates commands the most support; a social scientific survey may report the
most common of several responses to a question; or, a clinical trial may
compare binary patient outcomes under several treatment conditions to determine
the most effective treatment. Having observed the "winner" (largest observed
response) in a noisy experiment, it is natural to ask whether that candidate,
survey response, or treatment is actually the "best" (stochastically largest
response). This article concerns the problem of rank verification --- post hoc
significance tests of whether the orderings discovered in the data reflect the
population ranks. For exponential family models, we show under mild conditions
that an unadjusted two-tailed pairwise test comparing the top two observations
(i.e., comparing the "winner" to the "runner-up") is a valid test of whether
the winner is truly the best. We extend our analysis to provide equally simple
procedures to obtain lower confidence bounds on the gap between the winning
population and the others, and to verify ranks beyond the first.


title:
Statistical test for detecting community structure in real-valued
  edge-weighted graphs

abstract:
  We propose a novel method to test the existence of community structure of
undirected real-valued edge-weighted graph. The method is based on Wigner
semicircular law on the asymptotic behavior of the random distribution for
eigenvalues of a real symmetric matrix. We provide a theoretical foundation for
this method and report on its performance in synthetic and real data,
suggesting that our method outperforms other state-of-the-art methods.


title: A Neural Network for Coordination Boundary Prediction

abstract:
  We propose a neural-network based model for coordination boundary prediction.
The network is designed to incorporate two signals: the similarity between
conjuncts and the observation that replacing the whole coordination phrase with
a conjunct tends to produce a coherent sentences. The modeling makes use of
several LSTM networks. The model is trained solely on conjunction annotations
in a Treebank, without using external resources. We show improvements on
predicting coordination boundaries on the PTB compared to two state-of-the-art
parsers; as well as improvement over previous coordination boundary prediction
systems on the Genia corpus.


title:
Vertical flows and structures excited by magnetic activity in the
  Galactic center region

abstract:
  The vertical flow structure in the galactic center region remains poorly
understood. We analyzed the MHD simulation data by Suzuki et al. (2015) for
better understanding. As a result, we found the fast downflows with a speed of
~100 km/s near the foot-points of magnetic loops. These downflows are flowing
along a magnetic field line and accelerated by the gravity. The direction of
the fast flows is changed by the magnetic loop geometry, as it moves. As a
result, not only vertical motions but also azimuthal and radial motions are
excited. This feature could be relevant to the observed high velocity
dispersion in the position-velocity diagram.


abstract:
  In this paper, we study the Kadec-Klee property for convergence in measure of
noncommutative Orlicz spaces $L_{\varphi}(\widetilde{\mathcal{M}},\tau)$, where
$\widetilde{\mathcal{M}}$ is a von Neumann algebra, and $\varphi$ is an Orlicz
function. We show that if $\varphi\in\Delta_{2}$,
$L_{\varphi}(\widetilde{\mathcal{M}},\tau)$ has the Kadec-Klee property in
measure. As a corollary, the dual space and reflexivity of
$L_{\varphi}(\widetilde{\mathcal{M}},\tau)$ are given.


title:
Frobenius integrability and Finsler metrizability for $2$-dimensional
  sprays

abstract:
  For a $2$-dimensional non-flat spray we associate a Berwald frame and a
$3$-dimensional distribution that we call the Berwald distribution. The
Frobenius integrability of the Berwald distribution characterises the Finsler
metrizability of the given spray. In the integrable case, the sought after
Finsler function is provided by a closed, homogeneous $1$-form from the
annihilator of the Berwald distribution. We discuss both the degenerate and
non-degenerate cases using the fact that the regularity of the Finsler function
is encoded into a regularity condition of a $2$-form, canonically associated to
the given spray. The integrability of the Berwald distribution and the
regularity of the $2$-form have simple and useful expressions in terms of the
Berwald frame.


title: Compressing Neural Language Models by Sparse Word Representations

abstract:
  Neural networks are among the state-of-the-art techniques for language
modeling. Existing neural language models typically map discrete words to
distributed, dense vector representations. After information processing of the
preceding context words by hidden layers, an output layer estimates the
probability of the next word. Such approaches are time- and memory-intensive
because of the large numbers of parameters for word embeddings and the output
layer. In this paper, we propose to compress neural language models by sparse
word representations. In the experiments, the number of parameters in our model
increases very slowly with the growth of the vocabulary size, which is almost
imperceptible. Moreover, our approach not only reduces the parameter space to a
large extent, but also improves the performance in terms of the perplexity
measure.


title:
Degeneracy second main theorems for meromorphic mappings into projective
  varieties with hypersurfaces

abstract:
  The purpose of this paper has twofold. The first is to establish a second
main theorem with truncated counting functions for algebraically nondegenerate
meromorphic mappings into an arbitrary projective variety intersecting a family
of hypersurfaces in subgeneral position. In our result, the truncation level of
the counting functions is estimated explicitly. Our result is an extension of
the classical second main theorem of H. Cartan, also is a generalization of the
recent second main theorem of M. Ru and improves some recent results. The
second purpose of this paper is to give another proof for the second main
theorem for the special case where the projective variety is a projective
space, by which the truncation level of the counting functions is estimated
better than that of the general case.


title: Closed String Tachyon Driving $f(R)$ Cosmology

abstract:
  To study quantum effects on the bulk tachyon dynamics, we replace $R$ with
$f(R)$ in the low-energy effective action that couples gravity, the dilaton,
and the bulk closed string tachyon of bosonic closed string theory and study
properties of their classical solutions. The $\alpha^{\prime}$ corrections of
the graviton-dilaton-tachyon system are implemented in the $f(R)$. We obtain
the tachyon-induced rolling solutions and show that the string metric does not
need to remain fixed in some cases. The singular behavior of more classical
solutions are investigated and found to be modified by quantum effects. In
particular, there could exist some classical solutions, in which the tachyon
field rolls down from a maximum of the tachyon potential while the dilaton
expectation value is always bounded from above during the rolling process.


title:
Excitons in solids from time-dependent density-functional theory:
  Assessing the Tamm-Dancoff approximation

abstract:
  Excitonic effects in solids can be calculated using the Bethe-Salpeter
equation (BSE) or the Casida equation of time-dependent density-functional
theory (TDDFT). In both methods, the Tamm-Dancoff approximation (TDA), which
decouples excitations and de-excitations, is widely used to reduce
computational cost. Here, we study the effect of the TDA on exciton binding
energies of solids obtained from the Casida equation using long-range corrected
(LRC) exchange-correlation kernels. We find that the TDA underestimates
TDDFT-LRC exciton binding energies of semiconductors slightly, but those of
insulators significantly (i.e., by more than 100%), and thus it is essential to
solve the full Casida equation to describe strongly bound excitons. These
findings are relevant in the ongoing search for accurate and efficient TDDFT
approaches for excitons.


title:
Activation cross-sections of proton induced reactions on vanadium in the
  37-65 MeV energy range

abstract:
  Experimental excitation functions for proton induced reactions on natural
vanadium in the 37-65 MeV energy range were measured with the activation method
using a stacked foil irradiation technique. By using high resolution gamma
spectrometry cross-section data for the production of $^{51,48}$Cr, $^{48}$V,
$^{48,47,46,44m,44g,43}$Sc and $^{43,42}$K were determined. Comparisons with
the earlier published data are presented and results predicted by different
theoretical codes (EMPIRE and TALYS) are included. Thick target yields were
calculated from a fit to our experimental excitation curves and compared with
the earlier experimental yield data. Depth distribution curves to be used for
thin layer activation (TLA) are also presented.


title: Dialogue Session Segmentation by Embedding-Enhanced TextTiling

abstract:
  In human-computer conversation systems, the context of a user-issued
utterance is particularly important because it provides useful background
information of the conversation. However, it is unwise to track all previous
utterances in the current session as not all of them are equally important. In
this paper, we address the problem of session segmentation. We propose an
embedding-enhanced TextTiling approach, inspired by the observation that
conversation utterances are highly noisy, and that word embeddings provide a
robust way of capturing semantics. Experimental results show that our approach
achieves better performance than the TextTiling, MMD approaches.


title:
Local existence of smooth solutions to multiphase models in two space
  dimensions

abstract:
  In this paper, we consider a class of models for multiphase fluids, in the
framework of mixture theory. The considered system, in its more general form,
contains both the gradient of a hydrostatic pressure, generated by an
incompressibility constraint, and the gradient of a compressible pressure
depending on the volume fractions of some of the different phases. To approach
these systems, we define an approximation based on the \emph{Leray} projection,
which involves the use of the \emph{Lax} symbolic symmetrizer for hyperbolic
systems and paradifferential techniques. In two space dimensions, we prove its
well-posedness and convergence to the unique classical solution to the original
system. In the last part, we shortly discuss the difficulties in the three
dimensional case.


title: A Fuzzy Logic System to Analyze a Student's Lifestyle

abstract:
  A college student's life can be primarily categorized into domains such as
education, health, social and other activities which may include daily chores
and travelling time. Time management is crucial for every student. A self
realisation of one's daily time expenditure in various domains is therefore
essential to maximize one's effective output. This paper presents how a mobile
application using Fuzzy Logic and Global Positioning System (GPS) analyzes a
student's lifestyle and provides recommendations and suggestions based on the
results.


title:
Optimal Consumption and Investment with Fixed and Proportional
  Transaction Costs

abstract:
  The classical optimal investment and consumption problem with infinite
horizon is studied in the presence of transaction costs. Both proportional and
fixed costs as well as general utility functions are considered. Weak dynamic
programming is proved in the general setting and a comparison result for
possibly discontinuous viscosity solutions of the dynamic programming equation
is provided. Detailed numerical experiments illustrate several properties of
the optimal investment strategies.


title: Bijections between generalized Catalan families of types A and C

abstract:
  Motivated by the relation holding for the m-generalized Catalan numbers of
type A and C, the connection between dominant regions of the m-Shi arrangement
of type A and C is investigated. In the same line of thought, a bijection
between mn+1 copies of each m-Dyck path of height n and the set of NE lattice
paths inside an n times mn rectangle is provided.


title: Multi-view Consistency in UML

abstract:
  We study the question of consistency of multi-view models in UML and OCL. We
first critically survey the large amount of literature that already exists. We
find that only limited subsets of the UML/OCL have been covered so far and that
consistency checks mostly only cover structural aspects, whereas only few
methods also address behaviour. We also give a classification of different
techniques for multi-view UML/OCL consistency: consistency rules, the system
model approach, dynamic meta-modelling, universal logic, and heterogeneous
transformation. Finally, we elaborate cornerstones of a comprehensive
distributed semantics approach to consistency using OMG's Distributed Ontology,
Model and Specification Language (DOL).


title: Long N=2, 4 multiplets in supersymmetric mechanics

abstract:
  We define SU(2|1) supermultiplets described by chiral superfields having
non-zero external spins with respect to SU(2) \subset SU(2|1) and show that
their splitting into N=2, d=1 multiplets contains the so called "long"
indecomposable N=2, d=1 multiplets (2, 4, 2)_l. We give superfield formulation
for this type of N=2 long multiplets and construct their most general
superfield action. A simple example of long N=4, d=1 multiplet is also
considered, both in the superfield and the component formulations.


title: A simple proof of Feuerbach's theorem

abstract:
  The theorem of Feuerbach states that the nine-point circle of a
nonequilateral triangle is tangent to both its incircle and its three
excircles. We give a simple proof of this theorem.


title:
Initial-Boundary Value Problem for the heat equation - A stochastic
  algorithm

abstract:
  The Initial-Boundary Value Problem for the heat equation is solved by using a
new algorithm based on a random walk on heat balls. Even if it represents a
sophisticated generalization of the Walk on Spheres (WOS) algorithm introduced
to solve the Dirich-let problem for Laplace's equation, its implementation is
rather easy. The definition of the random walk is based on a new mean value
formula for the heat equation. The convergence results and numerical examples
permit to emphasize the efficiency and accuracy of the algorithm.


title:
Dynamic Domains of DTS: Simulations of a Spherical Magnetized Couette
  Flow

abstract:
  The Derviche Tourneur Sodium experiment, a spherical Couette
magnetohydrodynamics experiment with liquid sodium as the medium and a dipole
magnetic field imposed from the inner sphere, recently underwent upgrades to
its diagnostics to better characterize the flow and induced magnetic fields
with global rotation. In tandem with the upgrades, a set of direct numerical
simulations were run with the xshells code to give a more complete view of the
fluid and magnetic dynamics at various rotation rates of the inner and outer
spheres. These simulations reveal several dynamic regimes, determined by the
Rossby number. At positive differential rotation there is a regime of
quasigeostrophic flow, with low levels of fluctuations near the outer sphere.
Negative differential rotation shows a regime of what appear to be saturated
hydrodynamic instabilities at low negative differential rotation, followed by a
regime where filamentary structures develop at low latitudes and persist over
five to ten differential rotation periods as they drift poleward. We emphasize
that all these coherent structures emerge from turbulent flows. At least some
of them seem to be related to linear instabilities of the mean flow. The
simulated flows can produce the same measurements as those that the physical
experiment can take, with signatures akin to those found in the experiment.
This paper discusses the relation between the internal velocity structures of
the flow and their magnetic signatures at the surface.


title: Complex moment problem and recursive relations

abstract:
  We introduce a new strategy in solving the truncated complex moment problem.
To this aim we investigate recursive doubly indexed sequences and their
characteristic polynomials. A characterization of recursive doubly indexed
\emph{moment} sequences is provided. As a simple application, we obtain a
computable solution to the complex moment problem for cubic harmonic
characteristic polynomials of the form $z^3+az+b\overline{z}$, where $a$ and
$b$ are arbitrary real numbers. We also recapture a recent result due to
Curto-Yoo given for cubic column relations in $M(3)$ of the form
$Z^3=itZ+u\overline{Z}$ with $t,u$ real numbers satisfying some suitable
inequalities. Furthermore, we solve the truncated complex moment problem with
column dependence relations of the form $Z^{k+1}= \sum\limits_{0\leq n+ m \leq
k} a_{nm} \overline{Z}^n Z^m$ ($a_{nm} \in \mathbb{C}$).


title:
Isometric representation of Lipschitz-free spaces over convex domains in
  finite-dimensional spaces

abstract:
  Let $E$ be a finite-dimensional normed space and $\Omega$ a nonempty convex
open set in $E$. We show that the Lipschitz-free space of $\Omega$ is
canonically isometric to the quotient of $L^1(\Omega,E)$ by the subspace
consisting of vector fields with zero divergence in the sense of distributions
on $E$.


title:
Distilling momentum-space entanglement in Luttinger liquids at finite
  temperature

abstract:
  While much is known about the entanglement characteristics of ground states,
the properties of reduced thermal density matrices have received significantly
less attention. Here we investigate the entanglement content of reduced thermal
density matrices for momentum-space bipartitioning in Luttinger liquids using
analytical and numerical methods. The low lying part of its spectrum contains
an "entanglement gap", which persists up to temperatures comparable to the
level spacing. With increasing temperature, the low energy modes acquire
dispersion and resemble to those in the physical Hamiltonian with an enhanced
effective temperature. The momentum-space entanglement is carried by high
energy modes (compared to temperature), featuring a completely flat spectrum.
The von-Neumann entropy increases with temperature with a universal Sommerfeld
coefficient. The momentum-space entanglement Hamiltonian turns out to be as
universal as the physical Hamiltonian.


title:
Direct determination of the spin structure of Nd$_2$Ir$_2$O$_7$ by means
  of neutron diffraction

abstract:
  We report on the spin structure of the pyrochlore iridate Nd$_2$Ir$_2$O$_7$
that could be directly determined by means of powder neutron diffraction. Our
magnetic structure refinement unravels a so-called all-in/all-out magnetic
structure that appears in both, the Nd and the Ir sublattice. The ordered
magnetic moments at 1.8 K amount to 0.34(1) $\mu_\mathrm{B}$/Ir$^{4+}$ and
1.27(1) $\mu_\mathrm{B}$/Nd$^{3+}$. The Nd$^{3+}$ moment size at 1.8 K is
smaller than that expected for the Nd$^{3+}$ ground state doublet. On the other
hand, the size of the ordered moments of the Ir$^{4+}$ ions at 1.8 K agrees
very well with the value expected for a $J_\mathrm{eff}$ = 1/2 state based on
the presence of strong spin-orbit coupling in this system. Finally, our
measurements reveal a parallel alignment of the Nd$^{3+}$ moments with the net
moment of its six nearest neighboring Ir$^{4+}$ ions.


title: Spin wave excitations in the pyrovanadate alpha-Cu2V2O7

abstract:
  The pyrovanadate alpha-Cu2V2O7 belongs to the orthorhombic (Fdd2) class of
crystals with noncentrosymmetric crystal structure. Recently, the compound has
been identified to be a magnetic multiferroic with a substantial electric
polarization below the magnetic transition temperature TC = 35 K. Here we
report the results of our inelastic neutron scattering (INS) studies on a
polycrystalline sample of alpha-Cu2V2O7. Our INS data clearly show the
existence of dispersive spin wave excitations below TC with a zone-boundary
energy of 11 meV at 5 K.We have analyzed the data using linear spin wave
theory, which shows good agreement between the experiment and calculation. The
analysis is consistent with the third nearest neighbor exchange interaction
playing a dominant role in the magnetism of the material.


title: The bv algebra in string topology of classifying spaces

abstract:
  For almost any compact connected Lie group $G$ and any field $\mathbb{F}\_p$,
we compute the Batalin-Vilkoviskyalgebra $H^{*+\text{dim
}G}(LBG;\mathbb{F}\_p)$ on the loop cohomology of the classifying space
introduced byChataur and the second author.In particular, if $p$ is odd or
$p=0$, this Batalin-Vilkovisky algebra is isomorphicto the Hochschild
cohomology $HH^*(H\_*(G),H\_*(G))$. Over $\mathbb{F}\_2$, such isomorphism of
Batalin-Vilkovisky algebrasdoes not hold when $G=SO(3)$ or $G=G\_2$.


title:
Morphisms on infinite alphabets, countable states automata and regular
  sequences

abstract:
  In this paper, we prove that a class of regular sequences can be viewed as
projections of fixed points of uniform morphisms on a countable alphabet, and
also can be generated by countable states automata. Moreover, we prove that the
regularity of some regular sequences is invariant under some codings.


title: 1-well-covered graphs revisited

abstract:
  A graph is well-covered if all its maximal independent sets are of the same
size (M. D. Plummer, 1970). A well-covered graph is 1-well-covered if the
deletion of every vertex leaves a graph which is well-covered as well (J. W.
Staples, 1975). A graph G belongs to class W_{n} if every n pairwise disjoint
independent sets in G are included in $n$ pairwise disjoint maximum independent
sets (J. W. Staples, 1975). Clearly, W_{1} is the family of all well-covered
graphs. It turns out that G belongs to W_{2} if and only if it is a
1-well-covered graph without isolated vertices. We show that deleting a
shedding vertex does not change the maximum size of a maximal independent set
including a given independent set A in a graph G. Specifically, for
well-covered graphs, it means that the vertex v is shedding if and only if G-v
is well-covered. In addition, we provide new characterizations of
1-well-covered graphs, which we further use in building 1-well-covered graphs
by corona, join, and concatenation operations.


title: The Existence of Topological Edge States in Honeycomb Plasmonic Lattices

abstract:
  In this paper, we investigate the band properties of 2D honeycomb plasmonic
lattices consisting of metallic nanoparticles. By means of the coupled dipole
method and quasi-static approximation, we theoretically analyze the band
structures stemming from near-field interaction of localized surface plasmon
polaritons for both the infinite lattice and ribbons. Naturally, the
interaction of point dipoles decouples into independent out-of-plane and
in-plane polarizations. For the out-of-plane modes, both the bulk spectrum and
the range of the momentum $k_{\parallel}$ where edge states exist in ribbons
are similar to the electronic bands in graphene. Nevertheless, the in-plane
polarized modes show significant differences, which do not only possess
additional non-flat edge states in ribbons, but also have different
distributions of the flat edge states in reciprocal space. For in-plane
polarized modes, we derived the bulk-edge correspondence, namely, the relation
between the number of flat edge states at a fixed $k_\parallel$, Zak phases of
the bulk bands and the winding number associated with the bulk hamiltonian, and
verified it through four typical ribbon boundaries, i.e. zigzag, bearded
zigzag, armchair, and bearded armchair. Our approach gives a new topological
understanding of edge states in such plasmonic systems, and may also apply to
other 2D "vector wave" systems.


title: Anomalous Isotopic Effect of Tunneling States in NbTi-H/D

abstract:
  The thermal conductivity, heat capacity and heat release of NbTi, NbTi-H and
NbTi-D were measured at low temperatures. All three systems reveal low
temperature anomalies typical for structural glasses. It is shown that above a
concentration of 2\% H or D the tunneling states of the NbTi matrix disappear.
Therefore, for higher concentration it is a good system to proof how the change
of the mass of tunneling atoms influences the low temperature anomalies. For
the heat capacity we found the expected isotopic effect. However, the anomalous
isotopic effect observed for the heat release data cannot be explained within
the standard tunneling model. A surprising result is that tunneling systems
with very high barrier heights, even the systems with the maximum barrier
height, influence remarkable the heat capacity and the heat release data at low
temperatures. As a possible origin, we consider large-scale fluctuations in
thermal expansion which could generate anomalous two-level systems.


title: Dynamics of the Douglas-Rachford Method for Ellipses and p-Spheres

abstract:
  We expand upon previous work that examined behavior of the iterated
Douglas-Rachford method for a line and a circle by considering two
generalizations: that of a line and an ellipse and that of a line together with
a $p$-sphere. With computer assistance we discover a beautiful geometry that
illustrates phenomena which may affect the behavior of the iterates by slowing
or inhibiting convergence for feasible cases. We prove local convergence near
feasible points, and---seeking a better understanding of the behavior---we
employ parallelization in order to study behavior graphically. Motivated by the
computer-assisted discoveries, we prove a result about behavior of the method
in infeasible cases.


title: Jitter in Dynamical Systems with Intersecting Discontinuity Surfaces

abstract:
  Mathematical models involving switches --- in the form of differential
equations with discontinuities --- can accomodate real-world non-idealities
through perturbations by hysteresis, time-delay, discretization, and noise.
These are used to model the processes associated with switching in electronic
control, mechanical contact, predator-prey preferences, and genetic or cellular
regulation. The effect of such perturbations on rapid switching dynamics about
a single switch are somewhat benign: in the limit that the size of the
perturbation goes to zero the dynamics is given by Filippov's sliding solution.
When multiple switches are involved, however, perturbations can have
complicated effects, as shown in this paper. In the zero-perturbation limit,
hysteresis, time-delay, and discretization cause erratic variation or `jitter'
for stable sliding motion, whilst noise generates a relatively regular sliding
solution similar to the canopy solution (an extension of Filippov's solution to
multiple switches). We illustrate the results with a model of a switched power
circuit, and showcase a variety of complex phenomena that perturbations can
generate, including chaotic dynamics, exit selection, and coexisting sliding
solutions.


title: G-Graded Central Polynomials and G-Graded Posner's Theorem

abstract:
  Let F be characteristic zero field, G a residually finite group and W a
G-prime and PI F-algebra. By constructing G-graded central polynomials for W,
we prove the G-graded version of Posner's theorem. More precisely, if S denotes
all non-zero degree e central elements of W, the algebra S^{-1}W is G-graded
simple and finite dimensional over its center.
  Furthermore, we show how to use this theorem in order to recapture the result
of Aljadeff and Haile stating that two G-simple algebras of finite dimension
are isomorphix iff their ideals of graded identities coincide.


title:
High-efficiency generation of nanoscale single silicon vacancy defect
  array in silicon carbide

abstract:
  Color centers in silicon carbide have increasingly attracted attention in
recent years owing to their excellent properties such as single photon
emission, good photostability, and long spin coherence time even at room
temperature. As compared to diamond which is widely used for holding
Nitrogen-vacancy centers, SiC has the advantage in terms of large-scale,
high-quality and low cost growth, as well as advanced fabrication technique in
optoelectronics, leading to the prospects for large scale quantum engineering.
In this paper, we report experimental demonstration of the generation of
nanoscale $V_{Si}$ single defect array through ion implantation without the
need of annealing. $V_{Si}$ defects are generated in pre-determined locations
with resolution of tens of nanometers. This can help in integrating $V_{Si}$
defects with the photonic structures which, in turn, can improve the emission
and collection efficiency of $V_{Si}$ defects when it is used in spin photonic
quantum network. On the other hand, the defects are shallow and they are
generated $\sim 40nm$ below the surface which can serve as critical resources
in quantum sensing application.


title:
Strong coupling constant of negative parity octet baryons with light
  pseudoscalar mesons in light cone QCD sum rules

abstract:
  The strong coupling constants of the $\pi$ and $K$ mesons with negative
parity octet baryons are estimated within the light cone QCD sum rules. It is
observed that all strong coupling constants, similar to the case for the
positive parity baryons, can be described in terms of three invariant
functions, where two of them correspond to the well known $F$ and $D$ couplings
in the $SU(3)_f$ symmetry, and the third function describes the $SU(3)_f$
symmetry violating effects. We compare our predictions on the strong coupling
constants of pseudoscalar mesons of negative parity baryons with those
corresponding to the strong coupling constants for the positive parity baryons.


title:
Magnetic moment of $X_Q$ state with $J^{PC}=1^{+\pm}$ in light cone QCD
  sum rules

abstract:
  The magnetic moments of the recently observed resonance $X_b(5568)$ by DO
Collaboration and its partner with charm quark are calculated in the framework
of the light cone QCD sum rules, by assuming that these resonances are
represented as tetra--quark states with quantum numbers $J^{PC}=1^{+\pm}$. The
magnetic moment can play critical role in determination of the quantum numbers,
as well as giving useful information about the inner structure of these mesons.


title: Anomalous Tunneling Systems in Amorphous Organic Materials

abstract:
  We compare the heat release data of organic glasses with that of amorphous
and glass like crystalline solids. Anomalous behavior was found in all these
materials, which disagrees with the standard tunneling model. We can explain
the most of the experimental observations within a phenomenological model,
where we assume that for a part of tunneling systems the barrier heights are
strongly reduced as a consequence of the local stress produced during the
cooling process.


title:
Topological Phase Transition Coupled with Spin-Valley Physics in
  Ferroelectric Oxide Heterostructures

abstract:
  The possibility to engineer the coupling of spin and valley physics is
explored in ferroelectric oxide heterostructures with eg electronic
configuration. We show that the polar structural distortion induces the
appearance of spin-valley coupled properties, at the same time being
responsible for a topological transition from a quantum spin-Hall insulating
phase to a trivial band insulator. The coupled spin-valley physics is affected
by the topological band inversion in a non-trivial way; while the
valley-dependent spin polarization of both conduction and valence bands is
preserved, a change of the Berry curvature and of spin-valley selection rules
is predicted, leading to different circular dichroic response as well as valley
and spin Hall effects.


title: Pressure dependence of the band-gap energy in BiTeI

abstract:
  The evolution of the electronic structure of BiTeI, a layered semiconductor
with a van der Waals gap, under compression is studied by employing semilocal
and dispersion-corrected density-functional calculations. Comparative analysis
of the results of these calculations shows that the band-gap energy of BiTeI
decreases till it attains a minimum value of zero at a critical pressure, after
which it increases again. The critical pressure corresponding to the closure of
the band gap is calculated, at which BiTeI becomes a topological insulator.
Comparison of the critical pressure to the pressure at which BiTeI undergoes a
structural phase transition indicates that the closure of the band gap would
not be hindered by a structural transformation. Moreover, the band-gap pressure
coefficients of BiTeI are computed, and an expression of the critical pressure
is devised in terms of these coefficients. Our findings indicate that the
semilocal and dispersion-corrected approaches are in conflict about the
compressibility of BiTeI, which result in overestimation and underestimation,
respectively. Nevertheless, the effect of pressure on the atomic structure of
BiTeI is found to be manifested primarily as the reduction of the width of the
van der Waals gap according to both approaches, which also yield consistent
predictions concerning the interlayer metallic bonding in BiTeI under
compression. It is consequently shown that the calculated band-gap energies
follow qualitatively and quantitatively the same trend within the two
approximations employed here, and the transition to the zero-gap state occurs
at the same critical width of the van der Waals gap.


title:
Discrete restriction estimates of epsilon-removal type for kth-powers
  and k-paraboloids

abstract:
  We obtain restriction estimates of $\epsilon$-removal type for the set of
$k$-th powers of integers, and for discrete $d$-dimensional surfaces of the
form \[ \{ (n_1,\dots,n_d,n_1^k + \dotsb + n_d^k) \,:\, |n_1|,\dots,|n_d| \leq
N \}, \] which we term '$k$-paraboloids'. For these surfaces, we obtain a
satisfying range of exponents for large values of $d,k$. We also obtain
estimates of $\epsilon$-removal type in the full supercritical range for $k$-th
powers and for $k$-paraboloids of dimension $d < k(k-2)$. We rely on a variety
of techniques in discrete harmonic analysis originating in Bourgain's works on
the restriction theory of the squares and the discrete parabola.


title: Fodor's lemma can fail everywhere

abstract:
  We show that it is equiconsistent with $\mathsf{ZF}$ that Fodor's lemma fails
everywhere, and furthermore that the club filter on every regular cardinal is
not even $\sigma$-complete. Moreover, these failures can be controlled in a
very precise manner.


title: Geometric stability considerations of the ribosome flow model with pool

abstract:
  In order to better understand the process of gene translation, the ribosome
flow model (RFM) with pool was introduced recently. This model describes the
movement of several ribosomes along an mRNA template and simultaneously
captures the dynamics of the finite pool of ribosomes. Studying this system
with respect to the number and stability of its equilibria was so far based on
monotone systems theory (Margaliot and Tuller, 2012). We extend the results
obtained therein by using a geometric approach, showing that the equilibria of
the system constitute a normally hyperbolic invariant submanifold.
Subsequently, we analyze the Jacobi linearization of the system evaluated at
the equilibria in order to show that the equilibria are asymptotically stable
relative to certain affine subspaces. As this approach does not require any
monotonicity features of the system, it may also be applied for more complex
systems of the same kind such as bi-directional ribosome flows or time-varying
template numbers.


title: On the maximum mass of magnetised white dwarfs

abstract:
  We develop a detailed and self-consistent numerical model for
extremely-magnetised white dwarfs, which have been proposed as progenitors of
overluminous Type Ia supernovae. This model can describe fully-consistent
equilibria of magnetic stars in axial symmetry, with rotation,
general-relativistic effects and realistic equations of state (including
electron-ion interactions and taking into account Landau quantisation of
electrons due to the magnetic field). We study the influence of each of these
ingredients onto the white dwarf structure and, in particular, on their maximum
mass. We perform an extensive stability analysis of such objects, with their
highest surface magnetic fields reaching $\sim 10^{13}~G$ (at which point the
star adopts a torus-like shape). We confirm previous speculations that although
very massive strongly magnetised white dwarfs could potentially exist, the
onset of electron captures and pycnonuclear reactions may severely limit their
stability. Finally, the emission of gravitational waves by these objects is
addressed, showing no possibility of detection by the currently planned
space-based detector eLISA.


title:
Dictionary Update for NMF-based Voice Conversion Using an
  Encoder-Decoder Network

abstract:
  In this paper, we propose a dictionary update method for Nonnegative Matrix
Factorization (NMF) with high dimensional data in a spectral conversion (SC)
task. Voice conversion has been widely studied due to its potential
applications such as personalized speech synthesis and speech enhancement.
Exemplar-based NMF (ENMF) emerges as an effective and probably the simplest
choice among all techniques for SC, as long as a source-target parallel speech
corpus is given. ENMF-based SC systems usually need a large amount of bases
(exemplars) to ensure the quality of the converted speech. However, a small and
effective dictionary is desirable but hard to obtain via dictionary update, in
particular when high-dimensional features such as STRAIGHT spectra are used.
Therefore, we propose a dictionary update framework for NMF by means of an
encoder-decoder reformulation. Regarding NMF as an encoder-decoder network
makes it possible to exploit the whole parallel corpus more effectively and
efficiently when applied to SC. Our experiments demonstrate significant gains
of the proposed system with small dictionaries over conventional ENMF-based
systems with dictionaries of same or much larger size.


title:
Supersymmetric spin chains with non-monotonic dispersion relation:
  criticality and entanglement entropy

abstract:
  We study the critical behavior and the ground-state entanglement of a large
class of $\mathrm{su}(1|1)$ supersymmetric spin chains with a general (not
necessarily monotonic) dispersion relation. We show that this class includes
several relevant models, with both short- and long-range interactions of a
simple form. We determine the low temperature behavior of the free energy per
spin, and deduce that the models considered have a critical phase in the
universality class of a $(1+1)$-dimensional conformal field theory (CFT), whose
central charge coincides with the number of connected components of the Fermi
sea. We also study the R\'enyi entanglement entropy of the ground state,
deriving its asymptotic behavior as the block size tends to infinity. In
particular, we show that this entropy exhibits the logarithmic growth
characteristic of $(1+1)$-dimensional CFTs and one-dimensional (fermionic)
critical lattice models, with a central charge consistent with the
low-temperature behavior of the free energy. Our results confirm the widely
believed conjecture that the critical behavior of fermionic lattice models is
completely determined by the topology of their Fermi surface.

categories: quant-ph cond-mat.stat-mech math-ph math.MP nlin.SI


title:
Fourier-Motzkin Elimination Software for Information Theoretic
  Inequalities

abstract:
  We provide open-source software implemented in MATLAB, that performs
Fourier-Motzkin elimination (FME) and removes constraints that are redundant
due to Shannon-type inequalities (STIs). The FME is often used in information
theoretic contexts to simplify rate regions, e.g., by eliminating auxiliary
rates. Occasionally, however, the procedure becomes cumbersome, which makes an
error-free hand-written derivation an elusive task. Some computer software have
circumvented this difficulty by exploiting an automated FME process. However,
the outputs of such software often include constraints that are inactive due to
information theoretic properties. By incorporating the notion of STIs (a class
of information inequalities provable via a computer program), our algorithm
removes such redundant constraints based on non-negativity properties,
chain-rules and probability mass function factorization. This newsletter first
illustrates the program's abilities, and then reviews the contribution of STIs
to the identification of redundant constraints.


title: Preconditioning of a coupled Cahn--Hilliard Navier--Stokes system

abstract:
  Recently, Garcke et al.[Garcke, Hinze, Kahle, A stable and linear time
discretization for a thermodynamically consistent model for two-phase
incompressible flow, Applied Numerical Mathematics 99, pp. 151-171, 2016]
developed a consistent discretization scheme for a thermodynamically consistent
diffuse interface model for incompressible two-phase flows with different
densities. At the heart of this method lies the solution of large and sparse
linear systems that arise in a semismooth Newton method.
  We propose the use of preconditioned Krylov subspace solvers using effective
Schur complement approximations. Numerical results illustrate the efficiency of
our approach. In particular, our preconditioner is shown to be robust with
respect to parameter changes.


title: The Birman-Murakami-Wenzl Algebra of Coxeter Type D

abstract:
  The paper defines a generic Birman-Wenzl algebra of Coxeter Type D and
investigates its structure as a semi-simple algebra.


title: Dissipative soliton comb

abstract:
  Dissipative solitons are stable localized coherent structures with linear
frequency chirp generated in normal-dispersion mode-locked lasers. The soliton
energy in fiber lasers is limited by the Raman effect, but implementation of
intracavity feedback for the Stokes wave enables synchronous generation of a
coherent Raman dissipative soliton. Here we demonstrate a new approach for
generating chirped pulses at new wavelengths by mixing in a highly-nonlinear
fiber of two frequency-shifted dissipative solitons, as well as cascaded
generation of their clones forming a "dissipative soliton comb" in the
frequency domain. We observed up to eight equidistant components in a 400-nm
interval demonstrating compressibility from ~10 ps to ~300 fs. This approach,
being different from traditional frequency combs, can inspire new developments
in fundamental science and applications.


title: Three addressable spin qubits in a molecular single-ion magnet

abstract:
  We show that several qubits can be integrated in a single magnetic ion, using
its internal electronic spin states with energies tuned by a suitably chosen
molecular environment. This approach is illustrated with a nearly-isotropic
Gd(III) ion entrapped in a polyoxometalate molecule. Experiments with microwave
technologies, either three dimensional cavities or quantum superconducting
circuits, show that this magnetic molecule possesses the number of spin states
and the set of coherently addressable transitions connecting these states that
are needed to perform a universal three-qubit processor or, equivalently, a
d=8-level 'qudit'. Our findings open prospects for developing more
sophisticated magnetic molecules which can result in more powerful and noise
resilient quantum computation schemes.


title:
Semi-Supervised Active Learning for Support Vector Machines: A Novel
  Approach that Exploits Structure Information in Data

abstract:
  In our today's information society more and more data emerges, e.g.~in social
networks, technical applications, or business applications. Companies try to
commercialize these data using data mining or machine learning methods. For
this purpose, the data are categorized or classified, but often at high
(monetary or temporal) costs. An effective approach to reduce these costs is to
apply any kind of active learning (AL) methods, as AL controls the training
process of a classifier by specific querying individual data points (samples),
which are then labeled (e.g., provided with class memberships) by a domain
expert. However, an analysis of current AL research shows that AL still has
some shortcomings. In particular, the structure information given by the
spatial pattern of the (un)labeled data in the input space of a classification
model (e.g.,~cluster information), is used in an insufficient way. In addition,
many existing AL techniques pay too little attention to their practical
applicability. To meet these challenges, this article presents several
techniques that together build a new approach for combining AL and
semi-supervised learning (SSL) for support vector machines (SVM) in
classification tasks. Structure information is captured by means of
probabilistic models that are iteratively improved at runtime when label
information becomes available. The probabilistic models are considered in a
selection strategy based on distance, density, diversity, and distribution (4DS
strategy) information for AL and in a kernel function (Responsibility Weighted
Mahalanobis kernel) for SVM. The approach fuses generative and discriminative
modeling techniques. With 20 benchmark data sets and with the MNIST data set it
is shown that our new solution yields significantly better results than
state-of-the-art methods.


title: Bank Card Usage Prediction Exploiting Geolocation Information

abstract:
  We describe the solution of team ISMLL for the ECML-PKDD 2016 Discovery
Challenge on Bank Card Usage for both tasks. Our solution is based on three
pillars. Gradient boosted decision trees as a strong regression and
classification model, an intensive search for good hyperparameter
configurations and strong features that exploit geolocation information. This
approach achieved the best performance on the public leaderboard for the first
task and a decent fourth position for the second task.


title:
Interference effects of two scalar boson propagators on the LHC search
  for the singlet fermion DM

abstract:
  A gauge invariant UV-completion for singlet fermion DM interacting with the
standard model (SM) particles involves a new singlet scalar. Therefore the
model contains two scalar mediators, mixtures of the SM Higgs boson and a
singlet scalar boson. Collider phenomenology of the interference effect between
these two scalar propagators is studied in this work. This interference effect
can be either constructive or destructive in the DM production cross section
depending on both singlet scalar and DM masses, and it will soften the final
state jets in the full mass region. Applying the CMS mono-jet search to our
model, we find the interference effect plays a very important role in the DM
search sensitivity, and the DM production cross section of our model is more
than one order of magnitude below the LHC sensitivity at current stage.


title: Maximal equicontinuous generic factors and weak model sets

abstract:
  The orbit closures of regular model sets generated from a cut-and-project
scheme given by a co-compact lattice $\mathcal{L}\subset G\times H$ and compact
and aperiodic window $W\subseteq H$, have the maximal equicontinuous factor
(MEF) $(G\times H)/\mathcal{L}$, if the window is toplogically regular. This
picture breaks down completely, when the window has empty interior, in which
case the MEF is always trivial, although $(G\times H)/\mathcal{L}$ continues to
be the Kronecker factor for the Mirsky measure. As this situation occurs for
many interesting examples like the square-free numbers or the visible lattice
points, there is some need for a slightly weaker concept of topological factors
that is still strong enough to capture basic properties of the system. Here we
propose to use the concept of a generic factor \cite{HuangYe2012} for this
purpose. For so called ergodic topological dynamical systems we prove the
existence of a maximal equicontinuous generic factor (MEGF) and characterize it
in terms of the regional proximal relation. For such systems we also show that
the MEGF is trivial if and only if the system is topologically weakly mixing.
This part of the paper profits strongly from previous work by McMahon
\cite{McMahon1978} and Auslander \cite{Auslander1988}. In Section 3 we show
that $(G\times H)/\mathcal{L}$ is indeed the MEGF of the orbit closure of each
weak model set with an aperiodic Haar regulaar window, and in Section 4 we
apply this fact to give an alternative proof of the finding \cite{Mentzen2017}
that the centralizer of any $\mathcal{B}$-free dynamical system of Erd\"os type
is trivial.


title: Homomorphism bounds and edge-colourings of $K_4$-minor-free graphs

abstract:
  We present a necessary and sufficient condition for a graph of odd-girth
$2k+1$ to bound the class of $K_4$-minor-free graphs of odd-girth (at least)
$2k+1$, that is, to admit a homomorphism from any such $K_4$-minor-free graph.
This yields a polynomial-time algorithm to recognize such bounds. Using this
condition, we first prove that every $K_4$-minor free graph of odd-girth $2k+1$
admits a homomorphism to the projective hypercube of dimension $2k$. This
supports a conjecture of the third author which generalizes the four-color
theorem and relates to several outstanding conjectures such as Seymour's
conjecture on edge-colorings of planar graphs. Strengthening this result, we
show that the Kneser graph $K(2k+1,k)$ satisfies the conditions, thus implying
that every $K_4$-minor free graph of odd-girth $2k+1$ has fractional chromatic
number exactly $2+\frac{1}{k}$. Knowing that a smallest bound of odd-girth
$2k+1$ must have at least ${k+2 \choose 2}$ vertices, we build nearly optimal
bounds of order $4k^2$. Furthermore, we conjecture that the suprema of the
fractional and circular chromatic numbers for $K_4$-minor-free graphs of
odd-girth $2k+1$ are achieved by a same bound of odd-girth $2k+1$. If true,
this improves, in the homomorphism order, earlier tight results on the circular
chromatic number of $K_4$-minor-free graphs. We support our conjecture by
proving it for the first few cases. Finally, as an application of our work, and
after noting that Seymour provided a formula for calculating the edge-chromatic
number of $K_4$-minor-free multigraphs, we show that stronger results can be
obtained in the case of $K_4$-minor-free regular multigraphs.


title:
Inversion doublets of reflection-asymmetric clustering in 28Si and their
  isoscalar monopole and dipole transitions

abstract:
  [Background] Various cluster states of astrophysical interest are expected to
exist in the excited states of $^{28}{\rm Si}$. However, they have not been
identified firmly, because of the experimental and theoretical difficulties.
[Purpose] To establish the $^{24}$Mg+$\alpha$, $^{16}$O+$^{12}$C and
$^{20}$Ne+2$\alpha$ cluster bands, we theoretically search for the
negative-parity cluster bands that are paired with the positive-parity bands to
constitute the inversion doublets. We also offer the isoscalar monopole and
dipole transitions as a promising probe for the clustering. We numerically show
that these transition strengths from the ground state to the cluster states are
very enhanced. [Method] The antisymmetrized molecular dynamics with Gogny D1S
effective interaction is employed to calculate the excited states of $^{28}{\rm
Si}$. The isoscalar monopole and dipole transition strengths are directly
evaluated from wave functions of the ground and excited states. [Results]
Negative-parity bands having $^{24}$Mg+$\alpha$ and $^{16}$O+$^{12}$C cluster
configurations are obtained in addition to the newly calculated
$^{20}$Ne+2$\alpha$ cluster bands. All of them are paired with the
corresponding positive-parity bands to constitute the inversion doublets with
various cluster configurations. The calculation show that the band-head of the
$^{24}$Mg+$\alpha$ and $^{20}$Ne+2$\alpha$ cluster bands are strongly excited
by the isoscalar monopole and dipole transitions. [Conclusions] The present
calculation suggests the existence of the inversion doublets with the
$^{24}$Mg+$\alpha$, $^{16}$O+$^{12}$C and $^{20}$Ne+2$\alpha$
configurations.Because of the enhanced transition strengths, we offer the
isoscalar monopole and dipole transitions as good probe for the
$^{24}$Mg+$\alpha$ and $^{20}$Ne+2$\alpha$ cluster bands.


title: Engel structures and weakly hyperbolic flows on four-manifolds

abstract:
  We study pairs of Engel structures on four-manifolds whose intersection has
constant rank one and which define the same even contact structure, but induce
different orientations on it. We establish a correspondence between such pairs
of Engel structures and a class of weakly hyperbolic flows. This correspondence
is analogous to the correspondence between bi-contact structures and
projectively or conformally Anosov flows on three-manifolds found by
Eliashberg--Thurston and by Mitsumatsu.


title: Emergency Identification and Analysis with EAIMS

abstract:
  Social media platforms are now a key source of information for a large
segment of the public. As such, these platforms have a great potential as a
means to provide real-time information to emergency management agencies.
Moreover, during an emergency, these agencies are very interested in social
media as a means to find public-driven response efforts, as well as to track
how their handling of that emergency is being perceived. However, there is
currently a lack advanced tools designed for monitoring social media during
emergencies. The Emergency Analysis Identification and Management System
(EAIMS) is a prototype service that aims to fill this technology gap by
providing richer analytic and exploration tools than current solutions. In
particular, EAIMS provides real-time detection of emergency events, related
information finding, information access and credibility analysis tools for use
over social media during emergencies.


title: Adaptive timestepping strategies for nonlinear stochastic systems

abstract:
  We introduce a class of adaptive timestepping strategies for stochastic
differential equations with non-Lipschitz drift coefficients. These strategies
work by controlling potential unbounded growth in solutions of a numerical
scheme due to the drift. We prove that the Euler-Maruyama scheme with an
adaptive timestepping strategy in this class is strongly convergent. Specific
strategies falling into this class are presented and demonstrated on a
selection of numerical test problems. We observe that this approach is broadly
applicable, can provide more dynamically accurate solutions than a drift-tamed
scheme with fixed stepsize, and can improve MLMC simulations.


title:
$K^- N$ amplitudes below threshold constrained by multinucleon
  absorption

abstract:
  Six widely different subthreshold $K^- N$ scattering amplitudes obtained in
SU(3) chiral-model EFT approaches by fitting to low-energy and threshold data
are employed in optical-potential studies of kaonic atoms. Phenomenological
terms representing $K^-$ multinucleon interactions are added to the EFT
inspired single-nucleon part of the $K^-$-nucleus optical potential in order to
obtain good fits to kaonic-atom strong-interaction level shifts and widths
across the periodic table. Introducing as a further constraint the fractions of
single-nucleon $K^-$ absorption at rest from old bubble-chamber experiments, it
is found that only two of the models considered here reproduce these absorption
fractions. Within these two models, the interplay between single-nucleon and
multinucleon $K^-$ interactions explains features observed previously with
fully phenomenological optical potentials. Radial sensitivities of kaonic atom
observables are also re-examined, and remarks are made on the role of
`subthreshold kinematics' in absorption at rest calculations.


title: Stream Reasoning-Based Control of Caching Strategies in CCN Routers

abstract:
  Content-Centric Networking (CCN) research addresses the mismatch between the
modern usage of the Internet and its outdated architecture. Importantly, CCN
routers may locally cache frequently requested content in order to speed up
delivery to end users. Thus, the issue of caching strategies arises, i.e.,
which content shall be stored and when it should be replaced. In this work, we
employ novel techniques towards intelligent administration of CCN routers that
autonomously switch between existing strategies in response to changing content
request patterns. In particular, we present a router architecture for CCN
networks that is controlled by rule-based stream reasoning, following the
recent formal framework LARS which extends Answer Set Programming for streams.
The obtained possibility for flexible router configuration at runtime allows
for faster experimentation and may thus help to advance the further development
of CCN. Moreover, the empirical evaluation of our feasibility study shows that
the resulting caching agent may give significant performance gains.


title:
Finite-size corrections for universal boundary entropy in bond
  percolation

abstract:
  We compute the boundary entropy for bond percolation on the square lattice in
the presence of a boundary loop weight, and prove explicit and exact
expressions on a strip and on a cylinder of size $L$. For the cylinder we
provide a rigorous asymptotic analysis which allows for the computation of
finite-size corrections to arbitrary order. For the strip we provide exact
expressions that have been verified using high-precision numerical analysis.
Our rigorous and exact results corroborate an argument based on conformal field
theory, in particular concerning universal logarithmic corrections for the case
of the strip due to the presence of corners in the geometry. We furthermore
observe a crossover at a special value of the boundary loop weight.

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


title: Doppler speeds of the hydrogen Lyman lines in solar flares from EVE

abstract:
  The hydrogen Lyman lines provide important diagnostic information about the
dynamics of the chromosphere, but there have been few systematic studies of
their variability during flares. We investigate Doppler shifts in these lines
in several flares, and use these to calculate plasma speeds. We use spectral
data from the Multiple EUV Grating Spectrograph B (MEGS-B) detector of the
Extreme-Ultraviolet Variability Experiment (EVE) instrument on the Solar
Dynamics Observatory. MEGS-B obtains full-disk spectra of the Sun at a
resolution of 0.1nm in the range 37-105 nm, which we analyse using three
independent methods. The first method performs Gaussian fits to the lines, and
compares the quiet-Sun centroids with the flaring ones to obtain the Doppler
shifts. The second method uses cross-correlation to detect wavelength shifts
between the quiet-Sun and flaring line profiles. The final method calculates
the "center-of-mass" of the line profile, and compares the quiet-Sun and
flaring centroids to obtain the shift. In a study of 6 flares we find strong
signatures of both upflow and downflow in the Lyman lines, with speeds measured
in Sun-as-a-Star data of around 10 km/s, and speeds in the flare excess signal
of around 30 km/s All events showing upflows in Lyman lines are associated with
some kind of eruption or coronal flow in imaging data, which may be responsible
for the net blueshifts. Events showing downflows in the Lyman lines may be
associated with loop contraction or faint downflows, but it is likely that
chromospheric condensation flows are also contributing.


title:
Short timescale variables in stellar clusters: From Gaia to ground-based
  telescopes

abstract:
  Combined studies of variable stars and stellar clusters open great horizons,
and they allow us to improve our understanding of stellar cluster formation and
stellar evolution. In that prospect, the Gaia mission will provide astrometric,
photometric, and spectroscopic data for about one billion stars of the Milky
Way. This will represent a major census of stellar clusters, and it will
drastically increase the number of known variable stars. In particular, the
peculiar Gaia scanning law offers the opportunity to investigate the rather
unexplored domain of short timescale variability (from tens of seconds to a
dozen of hours), bringing invaluable clues to the fields of stellar physics and
stellar aggregates. We assess the Gaia capabilities in terms of short timescale
variability detection, using extensive light-curve simulations for various
variable object types. We show that Gaia can detect periodic variability
phenomena with amplitude variations larger than a few millimagnitudes.
Additionally, we plan to perform subsequent follow-up of variables stars
detected in clusters by Gaia to better characterize them. Hence, we develop a
pipeline for the analysis of high cadence photometry from ground-based
telescopes such as the 1.2m Euler telescope (La Silla, Chile) and the 1.2m
Mercator telescope (La Palma, Canary Islands).


title: Global symmetries, volume independence and continuity

abstract:
  We discuss quantum field theories with global $SU(N)$ and $O(N)$ symmetries
for which the temporal direction is compactified on a circle of size $L$ with
periodicity of fields up to a global symmetry transformation, i.e. twisted
boundary conditions. Such boundary conditions correspond to an insertion of the
global symmetry operator in the partition function. We argue that for a special
choice of twists most of the excited states get projected out, leaving only
either mesonic states or states whose energy scales with $N$. When
$N\rightarrow \infty$ all excitations become suppressed at any compact radius
and the twisted partition function gets a contribution from the ground-state
only, rendering observables independent of the radius of compactification, i.e.
volume independent. We explicitly prove that this is indeed the case for the
$CP(N-1)$ and $O(N)$ non-linear sigma models in any number of dimensions. We
further focus on the two-dimensional $CP(N-1)$ case which is asymptotically
free, and demonstrate, unlike its thermal counterpart, the twisted theory has
commuting $N\rightarrow\infty,L\rightarrow\infty$ limits and does not undergo a
second-order phase transition at "zero-temperature" discussed by Affleck long
ago. At finite $L$ the theory is described by an effective, zero-temperature
quantum mechanics with smoothly varying parameters depending on $L$,
eliminating the possibility of a phase transition at any $L$, which was
conjectured by \"Unsal and Dunne. As $L$ is decreased at fixed and finite $N$
the relevant objects dictating the $\theta$ dependence are quantum
kink-instantons, avatars of the small $L$ regime fractional instantons. These
considerations, for the first time establishes the idea of adiabatic continuity
advocated by \"Unsal et. al.


title:
An efficient strongly connected components algorithm in the fault
  tolerant model

abstract:
  In this paper we study the problem of maintaining the strongly connected
components of a graph in the presence of failures. In particular, we show that
given a directed graph $G=(V,E)$ with $n=|V|$ and $m=|E|$, and an integer value
$k\geq 1$, there is an algorithm that computes in $O(2^{k}n\log^2 n)$ time for
any set $F$ of size at most $k$ the strongly connected components of the graph
$G\setminus F$. The running time of our algorithm is almost optimal since the
time for outputting the SCCs of $G\setminus F$ is at least $\Omega(n)$. The
algorithm uses a data structure that is computed in a preprocessing phase in
polynomial time and is of size $O(2^{k} n^2)$.
  Our result is obtained using a new observation on the relation between
strongly connected components (SCCs) and reachability. More specifically, one
of the main building blocks in our result is a restricted variant of the
problem in which we only compute strongly connected components that intersect a
certain path. Restricting our attention to a path allows us to implicitly
compute reachability between the path vertices and the rest of the graph in
time that depends logarithmically rather than linearly in the size of the path.
This new observation alone, however, is not enough, since we need to find an
efficient way to represent the strongly connected components using paths. For
this purpose we use a mixture of old and classical techniques such as the heavy
path decomposition of Sleator and Tarjan and the classical Depth-First-Search
algorithm. Although, these are by now standard techniques, we are not aware of
any usage of them in the context of dynamic maintenance of SCCs. Therefore, we
expect that our new insights and mixture of new and old techniques will be of
independent interest.


title: Electronic control of magnonic and spintronic devices

abstract:
  Nanometric magnonic and spintronic devices need magnetic field control in
addition to conventional electronic control. In this work we review ways to
replace magnetic field control by an electronic one in order to circumvent
appearance of stray magnetic fields or the difficulty of creating large
magnetic fields over nanometric distances. Voltage control is compared to
current control and corresponding devices are compared from their energetic
efficiency point of view.


title:
Min cost flow on unit capacity networks and convex cost K-flow are as
  easy as the assignment problem with All-Min-Cuts algorithm

abstract:
  We explore here surprising links between the time-cost-tradeoff problem and
the minimum cost flow problem that lead to faster, strongly polynomial,
algorithms for both problems. One of the main results is a new algorithm for
the unit capacity min cost flow that culminates decades of efforts to match the
complexity of the fastest strongly polynomial algorithm known for the
assignment problem.
  The time cost tradeoff (TCT) problem in project management is to expedite the
durations of activities, subject to precedence constraints, in order to achieve
a target project completion time at minimum expediting costs, or, to maximize
the net benefit from a reward associated with project completion time
reduction. We devise here the all-min-cuts procedure, which for a given maximum
flow, is capable of generating all minimum cuts of equal value very efficiently
in average $O(m+n \log n)$ time.
  The all-min-cuts procedure implies faster algorithms for TCT problems: For a
project network on $n$ nodes and $m$ arcs, with $n'$ arcs of finite uniform
expediting costs, the run time is $O((n+n')(m+n\log n))$; for projects with
reward of $O(K)$ per unit reduction in the project completion time the run time
is $O((n+K)(m+n\log n))$.
  Using the primal-dual relationship between TCT and the minimum cost flow
problem (MCF) we generate faster strongly polynomial algorithms for various
cases of minimum cost flow: For the unit capacity MCF the complexity of our
algorithm is $O(n(m+n\log n))$, which is faster than any other strongly
polynomial known to date; For a minimum convex (or linear) cost $K$-flow
problem our algorithm runs in $O((n+K)(m+n\log n))$. This complexity of the
algorithm for any min cost $O(n)$-flow matches the best known complexity for
the assignment problem, $O(n(m+n\log n))$, yet with a significantly different
approach.


title: Entanglement-Assisted Quantum Error-Correcting Codes

abstract:
  We provide a self-contained introduction for entanglement-assisted quantum
error-correcting codes in this book chapter.


title:
VLT/SPHERE robust astrometry of the HR8799 planets at
  milliarcsecond-level accuracy Orbital architecture analysis with PyAstrOFit

abstract:
  HR8799 is orbited by at least four giant planets, making it a prime target
for the recently commissioned Spectro-Polarimetric High-contrast Exoplanet
REsearch (VLT/SPHERE). As such, it was observed on five consecutive nights
during the SPHERE science verification in December 2014. We aim to take full
advantage of the SPHERE capabilities to derive accurate astrometric
measurements based on H-band images acquired with the Infra-Red Dual-band
Imaging and Spectroscopy (IRDIS) subsystem, and to explore the ultimate
astrometric performance of SPHERE in this observing mode. We also aim to
present a detailed analysis of the orbital parameters for the four planets. We
report the astrometric positions for epoch 2014.93 with an accuracy down to 2.0
mas, mainly limited by the astrometric calibration of IRDIS. For each planet,
we derive the posterior probability density functions for the six Keplerian
elements and identify sets of highly probable orbits. For planet d, there is
clear evidence for nonzero eccentricity ($e \simeq 0.35$), without completely
excluding solutions with smaller eccentricities. The three other planets are
consistent with circular orbits, although their probability distributions
spread beyond $e = 0.2$, and show a peak at $e \simeq 0.1$ for planet e. The
four planets have consistent inclinations of about $30\deg$ with respect to the
sky plane, but the confidence intervals for the longitude of ascending node are
disjoint for planets b and c, and we find tentative evidence for
non-coplanarity between planets b and c at the $2 \sigma$ level.


title:
Stability estimates for a Magnetic Schrodinger operator with partial
  data

abstract:
  In this paper we study local stability estimates for a magnetic Schr\"odinger
operator with partial data on an open bounded set in dimension $n\geq 3$. This
is the corresponding stability estimates for the identifiability result
obtained by Bukgheim and Uhlmann $[2]$ in the presence of magnetic field and
when the measurements for the Dirichlet-Neumann map are taken on a neighborhood
of the illuminated region of the boundary for functions supported on a
neighborhood of the shadow region. We obtain $\log$-type estimates.


title: On boundary maps of Anosov representations of a surface group to SL(3,R)

abstract:
  We prove that Anosov representations from a surface group to SL(3,R) are
uniquely determined by their boundary maps if and only if they do not factor
over a completely reducible representation.
  Furthermore we discuss representations not distinguished by their boundary
maps, and we give a lower bound for the number of mapping class orbits of
components of the space of Anosov representations.


title: X-ray flaring in PDS 456 observed in a high-flux state

abstract:
  We present an analysis of a $190$\,ks (net exposure) \textit{Suzaku}
observation, carried out in 2007, of the nearby ($z=0.184$) luminous (L$_{\rm
bol}\sim10^{47}$\,erg\,s$^{-1}$) quasar PDS\,456. In this observation, the
intrinsically steep bare continuum is revealed compared to subsequent
observations, carried out in 2011 and 2013, where the source is fainter, harder
and more absorbed. We detected two pairs of prominent hard and soft flares,
restricted to the first and second half of the observation respectively. The
flares occur on timescales of the order of $\sim50$\,ks, which is equivalent to
a light-crossing distance of $\sim10\,R_{\rm g}$ in PDS\,456. From the spectral
variability observed during the flares, we find that the continuum changes
appear to be dominated by two components: (i) a variable soft component
($<2$\,keV), which may be related to the Comptonized tail of the disc emission,
and (ii) a variable hard power-law component ($>2$\,keV). The photon index of
the latter power-law component appears to respond to changes in the soft band
flux, increasing during the soft X-ray flares. Here the softening of the
spectra, observed during the flares, may be due to Compton cooling of the disc
corona induced by the increased soft X-ray photon seed flux. In contrast, we
rule out partial covering absorption as the physical mechanism behind the
observed short timescale spectral variability, as the timescales are likely too
short to be accounted for by absorption variability.


title:
Colloidal Joints with Designed Motion Range and Tunable Joint
  Flexibility

abstract:
  The miniaturization of machines towards the micron and nanoscales requires
the development of joint-like elements that enable and constrain motion. We
present a facile method to create colloidal joints, that is, anisotropic
colloidal particles containing surface mobile DNA linkers that control the
motion range of bonded particles. We demonstrate quantitatively that we can
control the flexibility of these colloidal joints by tuning the DNA linker
concentration in the bond area. We show that the colloidal shape controls the
range of motion that these colloidal joints enable, due to the finite-sized
patch of bonded linkers that cannot cross regions of high curvature. Finally we
demonstrate the potential of the colloidal joints for programmable bottom-up
self-assembly by creating flexible colloidal molecules and colloidal polymers.
The reconfigurability and motion constraint offered by our colloidal joints
make them promising building blocks for the development of switchable materials
and nanorobots.


title:
Voice Conversion from Non-parallel Corpora Using Variational
  Auto-encoder

abstract:
  We propose a flexible framework for spectral conversion (SC) that facilitates
training with unaligned corpora. Many SC frameworks require parallel corpora,
phonetic alignments, or explicit frame-wise correspondence for learning
conversion functions or for synthesizing a target spectrum with the aid of
alignments. However, these requirements gravely limit the scope of practical
applications of SC due to scarcity or even unavailability of parallel corpora.
We propose an SC framework based on variational auto-encoder which enables us
to exploit non-parallel corpora. The framework comprises an encoder that learns
speaker-independent phonetic representations and a decoder that learns to
reconstruct the designated speaker. It removes the requirement of parallel
corpora or phonetic alignments to train a spectral conversion system. We report
objective and subjective evaluations to validate our proposed method and
compare it to SC methods that have access to aligned corpora.


title: There is no Diophantine quintuple

abstract:
  A set of $m$ positive integers $\{a_1, a_2, \dots , a_m\}$ is called a
Diophantine $m$-tuple if $a_i a_j + 1$ is a perfect square for all $1 \le i < j
\le m$. In 2004 Dujella proved that there is no Diophantine sextuple and that
there are at most finitely many Diophantine quintuples. In particular, a
folklore conjecture concerning Diophantine $m$-tuples states that no
Diophantine quintuple exists at all. In this paper we prove this conjecture.


title: Liquid dynamics in partially crystalline glycerol

abstract:
  We present a dielectric study on the dynamics of supercooled glycerol during
crystallization. We explore the transformation into a solid phase in real time
by monitoring the temporal evolution of the amplitude of the dielectric signal.
Neither the initial nucleation or the crystal growth influence the liquid
dynamics visibly. For one of the samples studied, a tiny fraction of glycerol
remained in the disordered state after the end of the transition. We examined
the nature of the alpha relaxation in this frustrated crystal and find that it
is virtually identical to the bulk dynamics. In addition to that, we have found
no evidence that supercooled glycerol transforms into a peculiar phase where
either a new solid amorphous state or nano-crystals dispersed in a liquid
matrix are formed.


title:
Bounds for elimination of unknowns in systems of differential-algebraic
  equations

abstract:
  Elimination of unknowns in systems of equations, starting with Gaussian
elimination, is a problem of general interest. The problem of finding an a
priori upper bound for the number of differentiations in elimination of
unknowns in a system of differential-algebraic equations (DAEs) is an important
challenge, going back to Ritt (1932). The first characterization of this via an
asymptotic analysis is due to Grigoriev's result (1989) on quantifier
elimination in differential fields, but the challenge still remained.
  In this paper, we present a new bound, which is a major improvement over the
previously known results. We also present a new lower bound, which shows
asymptotic tightness of our upper bound in low dimensions, which are frequently
occurring in applications. Finally, we discuss applications of our results to
designing new algorithms for elimination of unknowns in systems of DAEs.


title: The variance conjecture on hyperplane projections of l_p^n balls

abstract:
  We show that for any $1\leq p\leq\infty$, the family of random vectors
uniformly distributed on hyperplane projections of the unit ball of $\ell_p^n$
verify the variance conjecture $$ \textrm{Var}\,|X|^2\leq C\max_{\xi\in
S^{n-1}}\mathbb{E}\langle X,\xi\rangle^2\mathbb{E}|X|^2, $$ where $C$ depends
on $p$ but not on the dimension $n$ or the hyperplane. We will also show a
general result relating the variance conjecture for a random vector uniformly
distributed on an isotropic convex body and the variance conjecture for a
random vector uniformly distributed on any Steiner symmetrization of it. As a
consequence we will have that the class of random vectors uniformly distributed
on any Steiner symmetrization of an $\ell_p^n$-ball verify the variance
conjecture.


title:
Transient birefringence of liquids induced by terahertz electric-field
  torque on permanent molecular dipoles

abstract:
  Microscopic understanding of low-frequency molecular motions in liquids has
been a longstanding goal in soft-matter science. So far, such low-frequency
motions have mostly been accessed indirectly by off-resonant optical pulses. A
more direct approach would be to interrogate the dynamic structure of liquids
with terahertz (THz) radiation. Here, we provide evidence that resonant
excitation with intense THz pulses is capable of driving
reorientational-librational modes of aprotic polar liquids through coupling to
the permanent molecular dipole moments. We observe a hallmark of this enhanced
coupling: a transient optical birefringence up to an order of magnitude higher
than obtained with optical excitation. Our results open up the path to
applications such as efficient molecular alignment and systematic study of the
coupling of rotational motion to other collective motions in liquids.


title: POPE: Partial Order Preserving Encoding

abstract:
  Recently there has been much interest in performing search queries over
encrypted data to enable functionality while protecting sensitive data. One
particularly efficient mechanism for executing such queries is order-preserving
encryption/encoding (OPE) which results in ciphertexts that preserve the
relative order of the underlying plaintexts thus allowing range and comparison
queries to be performed directly on ciphertexts. In this paper, we propose an
alternative approach to range queries over encrypted data that is optimized to
support insert-heavy workloads as are common in "big data" applications while
still maintaining search functionality and achieving stronger security.
Specifically, we propose a new primitive called partial order preserving
encoding (POPE) that achieves ideal OPE security with frequency hiding and also
leaves a sizable fraction of the data pairwise incomparable. Using only O(1)
persistent and $O(n^\epsilon)$ non-persistent client storage for
$0<\epsilon<1$, our POPE scheme provides extremely fast batch insertion
consisting of a single round, and efficient search with O(1) amortized cost for
up to $O(n^{1-\epsilon})$ search queries. This improved security and
performance makes our scheme better suited for today's insert-heavy databases.


title: Complexities Approach to Two Problems In Number Theory

abstract:
  By Kolmogorov Complexity,two number-theoretic problems are solved in
different way than before,one problem is Maxim Kontsevich and Don Bernard
Zagier's Problem 3 \emph{Exhibit at least one number which does not belong to}
$ \mathcal{P}$ (period number) in their paper,another is the problem about
existence of bounded coefficients of continued fraction expansion of
transcendental number.Thus we show a new approach to mathematical problems in
the non-logical discipline.Futhermore,we show that resource-bounded Kolmogorov
Complexity and computational complexity can at least provide tips or principles
to mathematical problems in the non-traditional or logical discipline.


title:
Compressive Cyclostationary Spectrum Sensing with a Constant False Alarm
  Rate

abstract:
  Spectrum sensing is a crucial component of opportunistic spectrum access
schemes, which aim at improving spectrum utilization by allowing for the reuse
of idle licensed spectrum. Sensing a spectral band before using it makes sure
the legitimate users are not disturbed. Since information about these users'
signals is not necessarily available, the sensor should be able to conduct
so-called blind spectrum sensing. Historically, this has not been a feature of
cyclostationarity-based algorithms. Indeed, in many application scenarios the
information required for traditional cyclostationarity detection might not be
available, hindering its practical applicability. In this work we propose two
new cyclostationary spectrum sensing algorithms that make use of the inherent
sparsity of the cyclic autocorrelation to make blind operation possible. Along
with utilizing sparse recovery methods for estimating the cyclic
autocorrelation, we take further advantage of its structure by introducing
joint sparsity as well as general structure dictionaries into the recovery
process. Furthermore, we extend a statistical test for cyclostationarity to
accommodate sparse cyclic spectra. Our numerical results demonstrate that the
new methods achieve a near constant false alarm rate behavior in contrast to
earlier approaches from the literature.