title: Supercharacters of unipotent and solvable groups

abstract:
  The notion of the supercharacter theory was introduced by P.Diaconis and
I.M.Isaaks in 2008. In this paper we review the main statements of the general
theory, we observe the construction of supercharacter theory for algebra groups
and the theory of basic characters for the unitriangular groups over the finite
field. Basing on the previous papers of the author, we construct the
supercharacter theory for the finite groups of triangular type. We characterize
the structure of Hopf algebra of supercharacters for the triangular group over
the finite field.


title: Thermal conductivity for stochastic energy exchange models

abstract:
  We consider a class of stochastic models for energy transport and study
relations between the thermal conductivity and some static observables, such as
the static conductivity, which is defined as the contribution of static
correlations in Green-Kubo formula. The class of models is a generalization of
two specific models derived by Gaspard and Gilbert as mesoscopic dynamics of
energies for two-dimensional and three-dimensional locally confined hard-discs.
They claim some equalities hold between the thermal conductivity and several
static observables and also conjecture that these equations are universal in
the sense that they hold for mesoscopic dynamics of energies for confined
particles interacting through hard-core collisions. In this paper, we give
sufficient and necessary conditions for these equalities to hold in the class
we introduce. In particular, we prove that the equality between the thermal
conductivity and other static observables holds if and only if the model obeys
the gradient condition. Since the gradient condition does not hold for models
derived by Gaspard and Gilbert, our result implies a part of their claim is
incorrect.


title:
Boundary triplets for skew-symmetric operators and the generation of
  strongly continuous semigroups

abstract:
  We give a self-contained and streamlined exposition of a generation theorem
for C0-semigroups based on the method of boundary triplets. We apply this
theorem to port-Hamiltonian systems where we discuss recent results appearing
in stability and control theory. We give detailed proofs and require only a
basic knowledge of operator and semigroup theory.


title: Are "Non-functional" Requirements really Non-functional?

abstract:
  Non-functional requirements (NFRs) are commonly distinguished from functional
requirements by differentiating how the system shall do something in contrast
to what the system shall do. This distinction is not only prevalent in
research, but also influences how requirements are handled in practice. NFRs
are usually documented separately from functional requirements, without
quantitative measures, and with relatively vague descriptions. As a result,
they remain difficult to analyze and test. Several authors argue, however, that
many so-called NFRs actually describe behavioral properties and may be treated
the same way as functional requirements. In this paper, we empirically
investigate this point of view and aim to increase our understanding on the
nature of NFRs addressing system properties. We report on the classification of
530 NFRs extracted from 11 industrial requirements specifications and analyze
to which extent these NFRs describe system behavior. Our results suggest that
most "non-functional" requirements are not non-functional as they describe
behavior of a system. Consequently, we argue that many so-called NFRs can be
handled similarly to functional requirements.


title:
Existence of multi-solitary waves with logarithmic relative distances
  for the NLS equation

abstract:
  We construct in this paper global (for $t \geq 0$) and bounded solutions
$u(t)$ for the nonlinear Schr\"odinger equation \[i \partial_t u + \Delta u +
|u|^{p-1} u = 0, \quad t \in \mathbb{R}, x \in \mathbb{R}^d\] in mass
sub-critical cases ($1 < p < 1 + \frac{4}{d}$) and mass super-critical ($1 +
\frac{4}{d} < p < \frac{d+2}{d-2}$) such that $u(t)$ decomposes asymptotically
into two solitary waves with logarithmic distance \[ \|u(t) - e^{i \gamma (t)}
\sum_{k=1}^2 Q(\cdot - x_k(t))\|_{H^1} \to 0 \] and \[|x_1(t) - x_2(t)| \sim 2
\log t, \quad \mbox{as}t \to + \infty.\] The logarithmic distance is related to
strong interactions between solitary waves. In the integrable case ($d=1$ and
$p=3$) the existence of such solutions has been shown in [14].


title: When the property of having a $\pi$-tree is preserved by products

abstract:
  We find sufficient conditions under which the product of spaces that have a
$\pi$-tree also has a $\pi$-tree. These conditions give new examples of spaces
with a $\pi$-tree: every at most countable power of the Sorgenfrey line and
every at most countable power of the irrational Sorgenfrey line has a
$\pi\!$-tree. Also we show that if a space has a $\pi$-tree, then its product
with the Baire space, with the Sorgenfrey line, and with the countable power of
the Sorgenfrey line also has a $\pi$-tree.


title: Using Stable Distributions to Characterize Proton Pencil Beams

abstract:
  Purpose: To introduce and evaluate the use of stable distributions as a means
of describing the behavior of charged particle pencil beams in a medium, with
specific emphasis on proton beam scanning (PBS). Methods: The proton pencil
beams of a clinically commissioned proton treatment facility are replicated in
a Monte Carlo simulation system (FLUKA). For each available energy the beam
deposition in water medium is characterized by the dose deposition. Using an
alpha--stable distribution methodology each beam with a nominal energy $E$ is
characterized by the lateral spread at depth $z$: $S(z;\alpha,\gamma,E)$ and a
total energy deposition $I_D(z)$. The beams are then described as a function of
the variation of the parameters at depth. Finally, an implementation in a
freely available open source dose calculation suite (matRad, DKFZ, Heidelberg,
Germany) is proposed. Results: Quantitatively, the fit of the stable
distributions, compared to those implemented in standard treatment planning
systems, are equivalent. The efficiency of the representation is better (2
compared to 3 and more parameters needed). The meta--parametrization (i.e. the
description of the dose deposition by only providing the fitted parameters)
allows for interpolation of non--measured data. In the case of the clinical
data used in this paper, it was possible to only commission 1 out of 5 nominal
energies to obtain a viable data set. Conclusions: Alpha--stable distributions
are intrinsically suited to describe charged particle pencil beams in a medium
and can be easily implemented in existing treatment planning systems. The use
of alpha-distributions can easily be extended to other particles.


title:
The center of the small quantum group u_q(sl_3) for l=5: a numerical
  computation

abstract:
  This is a brief note on a numerical computation of the dimension of the
center of the small quantum group u_q(sl_3) at the 5th root of unity. The
obtained dimension is 57. Using the description of the regular block of the
center for u_q(sl_3), given in arXiv:1604.07380, we conclude that the dimension
of the singular parabolic block of the center for u_q(sl_3) is 6, and obtain a
complete block decomposition of the center in this case.


title:
Real-time measurement of nanotube resonator fluctuations in an electron
  microscope

abstract:
  Mechanical resonators based on low-dimensional materials provide a unique
platform for exploring a broad range of physical phenomena. The mechanical
vibrational states are indeed extremely sensitive to charges, spins, photons,
and adsorbed masses. However, the roadblock is often the readout of the
resonator, since the detection of the vibrational states becomes increasingly
difficult for smaller resonators. Here, we report an unprecedentedly sensitive
method to detect nanotube resonators with effective masses in the 10^-20 kg
range. We use the beam of an electron microscope to resolve the mechanical
fluctuations of a nanotube in real-time for the first time. We obtain full
access to the thermally-driven Brownian motion of the resonator, both in space
and time domains. Our results establish the viability of carbon nanotube
resonator technology at room temperature and pave the way towards the
observation of novel thermodynamics regimes and quantum effects in
nano-mechanics.


title:
A large sample test for the length of memory of stationary symmetric
  stable random fields via nonsingular $\mathbb{Z}^d$-actions

abstract:
  Based on the ratio of two block maxima, we propose a large sample test for
the length of memory of a stationary symmetric $\alpha$-stable discrete
parameter random field. We show that the power function converges to one as the
sample-size increases to infinity under various classes of alternatives having
longer memory in the sense of Samorodnitsky(2004). Ergodic theory of
nonsingular $\mathbb{Z}^d$-actions play a very important role in the design and
analysis of our large sample test.


title: Comment on A First-order Phase Transition to Metallic Hydrogen

abstract:
  A recent paper by Zaghoo et al. presents optical data at high-pressure and
high-temperature and interprets the data as evidence for a first-order phase
transition to metallic hydrogen during heating. Here we argue that the
presented data are contradictory with these claims. Elucidating this issue is
important for building a coherent picture that is emerging as the results of
theoretical calculations of various levels and experimental investigations
employing static and dynamic compression techniques. In this context, the use
of adequate probes of the electronic and chemical state is crucial. Optical
probes that do not address the energy dependent conductivity while making
multiple references to the Drude model are highly speculative. Indeed, the
available dynamic and static compression data and theoretical modeling show
that study of energy dependent conductivity is important for understanding the
nature of hot dense hydrogen. Moreover, the most recent investigations suggest
that the critical point, which demarcates the regimes of crossover between
insulating and plasma state at low densities to the first order liquid-liquid
transition, is above 200 GPa. Below we concentrate on inconsistencies in the
interpretation of data in Zaghoo et al, which call for careful examination of
their claims and further detailed investigations. We analyze their optical data
and use finite element calculations and argue that the high-temperature state
studied in Zaghoo et al. is not metallic and that the data cannot discriminate
between a first-order phase transition and a continuous phase transition, or
even a bandgap drop within one phase


title: Genus-One Mirror Symmetry in the Landau-Ginzburg Model

abstract:
  We prove an explicit formula for the genus-one Fan-Jarvis-Ruan-Witten
invariants associated to the quintic threefold, verifying the genus-one mirror
conjecture of Huang, Klemm, and Quackenbush. The proof involves two steps. The
first step uses localization on auxiliary moduli spaces to compare the usual
Fan-Jarvis-Ruan-Witten invariants with a semisimple theory of twisted
invariants. The second step uses the genus-one formula for semisimple
cohomological field theories to compute the twisted invariants explicitly.


title:
On the stability of type II blowup for the 1-corotational energy
  supercritical harmonic heat flow

abstract:
  We consider the energy supercritical harmonic heat flow from $\mathbb{R}^d$
into the $d$-sphere $\mathbb{S}^d$ with $d \geq 7$. Under an additional
assumption of 1-corotational symmetry, the problem reduces to the one
dimensional semilinear heat equation $$\partial_t u = \partial^2_r u +
\frac{(d-1)}{r}\partial_r u - \frac{(d-1)}{2r^2}\sin(2u).$$ We construct for
this equation a family of $\mathcal{C}^{\infty}$ solutions which blow up in
finite time via concentration of the universal profile $$u(r,t) \sim
Q\left(\frac{r}{\lambda(t)}\right),$$ where $Q$ is the stationary solution of
the equation and the speed is given by the quantized rates $$\lambda(t) \sim
c_u(T-t)^\frac{\ell}{\gamma}, \quad \ell \in \mathbb{N}^*, \;\; 2\ell > \gamma
= \gamma(d) \in (1,2].$$ The construction relies on two arguments: the
reduction of the problem to a finite-dimensional one thanks to a robust
universal energy method and modulation techniques developed by Merle, Rapha\"el
and Rodnianski [Camb. Jour. Math, 3(4):439-617, 2015] for the energy
supercritical nonlinear Schr\"odinger equation and by Rapha\"el and Schweyer
[Anal. PDE, 7(8):1713-1805, 2014] for the energy critical harmonic heat flow,
then we proceed by contradiction to solve the finite-dimensional problem and
conclude using the Brouwer fixed point theorem. Moreover, our constructed
solutions are in fact $(\ell - 1)$ codimension stable under perturbations of
the initial data. As a consequence, the case $\ell = 1$ corresponds to a stable
type II blowup regime.


title: Gravitational closure of matter field equations

abstract:
  The requirement that both the matter and the geometry of a spacetime
canonically evolve together, starting and ending on shared Cauchy surfaces and
independently of the intermediate foliation, leaves one with little choice for
diffeomorphism-invariant gravitational dynamics that can provide consistent
evolution equations to the coefficients of a given system of matter field
equations. Concretely, we show how starting from any linear local matter field
equations whose principal polynomial satisfies three physicality conditions,
one may calculate coefficient functions which then enter an otherwise immutable
set of countably many linear homogeneous partial differential equations. Any
solution of these so-called gravitational closure equations then provides a
Lagrangian density for any type of tensorial geometry that features
ultralocally in the initially specified matter Lagrangian density. Thus the
given system of matter field equations is indeed closed by the so obtained
gravitational equations. In contrast to previous work, we build the theory on a
suitable associated bundle encoding the canonical configuration degrees of
freedom, which allows to include necessary constraints on the geometry in
practically tractable fashion. By virtue of the presented mechanism, one thus
can practically calculate, rather than having to postulate, the gravitational
theory that is required by specific matter field dynamics. For the special case
of standard model matter one obtains general relativity.


title:
Semiclassics for matrix Hamiltonians: The Gutzwiller trace formula and
  applications to the graphene-type systems

abstract:
  We have extended the semi-classical theory to include a general account of
matrix valued Hamiltonians, i.e. those that describe quantum systems with
internal degrees of freedoms, based on a generalization of the Gutzwiller trace
formula for a $n\times n$ dimensional Hamiltonian $H(\hat{\boldsymbol
p},\hat{\boldsymbol q})$. The classical dynamics is governed by $n$
Hamilton-Jacobi (HJ) equations, that act in a phase space endowed with a
classical Berry curvature encoding anholonomy in the parallel transport of the
eigenvectors of $H(\hat{\boldsymbol p}\to\boldsymbol p,\hat{\boldsymbol
q}\to\boldsymbol q)$, which describe the internal structure of the
semi-classical particles. This Berry curvature is a fully classical object and
is, in that sense, as fundamental to the semi-classical theory of matrix
Hamiltonians as the Hamilton-Jacobi equations. At the $\mathcal{O}(\hbar^1)$
level, it results in an additional semi-classical phase composed of (i) a Berry
phase and (ii) a dynamical phase resulting from the classical particles "moving
through the Berry curvature". We show that the dynamical part of this
semi-classical phase will, generally, only be zero only for the case in which
the Berry phase is topological (i.e. depends only on the winding number). We
illustrate the method by calculating the Landau spectrum for monolayer
graphene, the four-band model of AB bilayer graphene, and for a more
complicated matrix Hamiltonian describing the silicene band structure. Finally
we apply our method to an inhomogeneous system consisting of a strain
engineered one dimensional moir\'e in bilayer graphene, finding localized
states near the Dirac point that arise from electron trapping in a
semi-classical moir\'e potential. The semi-classical density of states of these
localized states we show to be in perfect agreement with an exact quantum
mechanical calculation of the density of states.


title: Paths counting on simple graphs: from escape to localization

abstract:
  We study the asymptotic behavior of the number of paths of length $N$ on
several classes of infinite graphs with a single special vertex. This vertex
can work as an entropic trap for the path, i.e. under certain conditions the
dominant part of long paths become localized in the vicinity of the special
point instead of spreading to infinity. We study the conditions for such
localization on decorated star graphs, regular trees and regular hyperbolic
graphs as a function of the functionality of the special vertex. In all cases
the localization occurs for large enough functionality. The particular value of
transition point depends on the large-scale topology of the graph. The
emergence of localization is supported by the analysis of the spectra of the
adjacency matrices of corresponding finite graphs.


title: Codualizing modules

abstract:
  Let $(R, \mathfrak{m})$ be a Noetherian local ring. In this paper, we
introduce a dual notion for dualizing modules, namely codualizing modules. We
study the basic properties of codualizing modules and use them to establish an
equivalence between the category of noetherian modules of finite projective
dimension and the category of artinian modules of finite projective dimension.
Next, we give some applications of codualizing modules. Finally, we present a
mixed identity involving quasidualizing module that characterize the
codualizing module. As an application, we obtain a necessary and sufficient
condition for $R$ to be Gorenstein.


title:
Leaky Wires: Information Leakage and Covert Communication Between FPGA
  Long Wires

abstract:
  Field-Programmable Gate Arrays (FPGAs) are integrated circuits that implement
reconfigurable hardware. They are used in modern systems, creating specialized,
highly-optimized integrated circuits without the need to design and manufacture
dedicated chips. As the capacity of FPGAs grows, it is increasingly common for
designers to incorporate implementations of algorithms and protocols from a
range of third-party sources. The monolithic nature of FPGAs means that all
on-chip circuits, including third party black-box designs, must share common
on-chip infrastructure, such as routing resources. In this paper, we observe
that a "long" routing wire carrying a logical 1 reduces the propagation delay
of other adjacent but unconnected long wires in the FPGA interconnect, thereby
leaking information about its state. We exploit this effect and propose a
communication channel that can be used for both covert transmissions between
circuits, and for exfiltration of secrets from the chip. We show that the
effect is measurable for both static and dynamic signals, and that it can be
detected using very small on-board circuits. In our prototype, we are able to
correctly infer the logical state of an adjacent long wire over 99% of the
time, even without error correction, and for signals that are maintained for as
little as 82us. Using a Manchester encoding scheme, our channel bandwidth is as
high as 6kbps. We characterize the channel in detail and show that it is
measurable even when multiple competing circuits are present and can be
replicated on different generations and families of Xilinx devices (Virtex 5,
Virtex 6, and Artix 7). Finally, we propose countermeasures that can be
deployed by systems and tools designers to reduce the impact of this
information leakage.


title:
Nonlinear Wave Equation with Damping: Periodic Forcing and Non-Resonant
  Solutions to the Kuznetsov Equation

abstract:
  Existence of non-resonant solutions of time-periodic type are established for
the Kuznetsov equation with a periodic forcing term. The equation is considered
in a three-dimensional whole-space, half-space and bounded domain, and with
both non-homogeneous Dirichlet and Neumann boundary values. A method based on
Lp estimates of the corresponding linearization, namely the wave equation with
Kelvin-Voigt damping, is employed.


title: Spectral Evolution in High Redshift Quasars from the Final BOSS Sample

abstract:
  We report on the diversity in quasar spectra from the Baryon Oscillation
Spectroscopic Survey. After filtering the spectra to mitigate selection effects
and Malmquist bias associated with a nearly flux-limited sample, we create high
signal-to-noise ratio composite spectra from 58,656 quasars (2.1 \le z \le
3.5), binned by luminosity, spectral index, and redshift. With these composite
spectra, we confirm the traditional Baldwin effect (BE, i.e., the
anticorrelation of C IV equivalent width (EW) and luminosity) that follows the
relation W_\lambda \propto L^{\beta_w} with slope \beta_w = -0.35 \pm 0.004,
-0.35 \pm 0.005, and -0.41 \pm 0.005 for z = 2.25, 2.46, and 2.84,
respectively. In addition to the redshift evolution in the slope of the BE, we
find redshift evolution in average quasar spectral features at fixed
luminosity. The spectroscopic signature of the redshift evolution is correlated
at 98% with the signature of varying luminosity, indicating that they arise
from the same physical mechanism. At a fixed luminosity, the average C IV FWHM
decreases with increasing redshift and is anti-correlated with C IV EW. The
spectroscopic signature associated with C IV FWHM suggests that the trends in
luminosity and redshift are likely caused by a superposition of effects that
are related to black hole mass and Eddington ratio. The redshift evolution is
the consequence of a changing balance between these two quantities as quasars
evolve toward a population with lower typical accretion rates at a given black
hole mass.


title:
The law of large numbers for the maximum of almost Gaussian
  log-correlated fields coming from random matrices

abstract:
  We compute the leading asymptotics as $N\to\infty$ of the maximum of the
field $Q_N(q)= \log\det|q- A_N|$, $q\in \mathbb{C}$, for any unitarily
invariant Hermitian random matrix $A_N$ associated to a non-critical
real-analytic potential. Hence, we verify the leading order in a conjecture of
Fyodorov and Simm formulated for the GUE. The method relies on a classical
upper-bound and a more sophisticated lower-bound based on a variant of the
second-moment method which exploits the hyperbolic branching structure of the
field $Q_N(q)$, $q$ in the upper half plane. Specifically, we compare $Q_N$ to
an idealized Gaussian field by means of exponential moments. In principle, this
method could also be applied to random fields coming from other point processes
provided that one can compute certain mixed exponential moments. For unitarily
invariant ensembles, we show that these assumptions follow from the
Fyodorov-Strahov formula and asymptotics of orthogonal polynomials derived by
Deift, Kriecherbauer, McLaughlin, Venakides, and Zhou.


title:
Transmission Policies for Interference Management in Full-Duplex D2D
  Communication

abstract:
  Full-Duplex (FD) wireless and Device-to-Device (D2D) communication are two
promising technologies that aspire to enhance the spectrum and energy
efficiency of wireless networks, thus fulfilling key requirements of the 5th
generation (5G) of mobile networks. Both technologies, however, generate
excessive interference, which, if not managed effectively, threatens to
compromise system performance. To this direction, we propose two transmission
policies that enhance the communication of two interfering FD-enabled D2D
pairs, derived from game theory and optimization theory. The game-theoretic
policy allows the pairs to choose their transmission modes independently and
the optimal policy to maximize their throughput, achieving significant gains
when the pairs interfere strongly with each other.


title:
On the origin of the anomalous compliance of dealloying-derived
  nanoporous gold

abstract:
  The origin of the anomalously compliant behavior of nanoporous gold is
studied by comparing the elasticity obtained from molecular dynamics (MD) and
finite element method (FEM) simulations. Both models yield a compliance, which
is much higher than the predictions of the Gibson-Ashby scaling relation for
metal foams and thus confirm the influence of other microstructural features
besides the porosity. The linear elastic FEM simulation also yields a
substantially stiffer response than the MD simulation, which reveals that
nonlinear elastic behavior contributes decisively to the anomalous compliance
of nanoporous gold at small structure size.


title: Propositions in Linear Multirole Logic as Multiparty Session Types

abstract:
  We identify multirole logic as a new form of logic and formalize linear
multirole logic (LMRL) as a natural generalization of classical linear logic
(CLL). Among various meta-properties established for LMRL, we obtain one named
multi-cut elimination stating that every cut between three (or more) sequents
(as a generalization of a cut between two sequents) can be eliminated, thus
extending the celebrated result of cut-elimination by Gentzen. We also present
a variant of $\pi$-calculus for multiparty sessions that demonstrates a tight
correspondence between process communication in this variant and multi-cut
elimination in LMRL, thus extending some recent results by Caires and Pfenning
(2010) and Wadler (2012), among others, along a similar line of work.


title: Security Management Model in Cloud Computing Environment

abstract:
  In the cloud computing environment, cloud virtual machine (VM) will be more
and more the number of virtual machine security and management faced giant
Challenge. In order to address security issues cloud computing virtualization
environment, this paper presents a virtual machine based on efficient and
dynamic deployment VM security management model state migration and scheduling,
study of which virtual machine security architecture, based on AHP (Analytic
Hierarchy Process) virtual machine deployment and scheduling method, based on
CUSUM (Cumulative Sum) DDoS attack detection algorithm, and the above-described
method for functional testing and validation.


title: Positive Quantum Magnetoresistance in Tilted Magnetic Field

abstract:
  Transport properties of highly mobile 2D electrons are studied in symmetric
GaAs quantum wells placed in titled magnetic fields. Quantum positive
magnetoresistance (QPMR) is observed in magnetic fields perpendicular to the 2D
layer. Application of in-plane magnetic field produces a dramatic decrease of
the QPMR. This decrease correlates strongly with the reduction of the amplitude
of Shubnikov de Haas resistance oscillations due to modification of the
electron spectrum via enhanced Zeeman splitting. Surprisingly no quantization
of the spectrum is detected when the Zeeman energy exceeds the half of the
cyclotron energy suggesting an abrupt transformation of the electron dynamics.
Observed angular evolution of QPMR implies strong mixing between spin subbands.
Theoretical estimations indicate that in the presence of spin-orbital
interaction the elastic impurity scattering provides significant contribution
to the spin mixing in GaAs quantum wells at high filling factors.


title:
Centralized Load Shedding Based on Thermal Limit of Transmission Lines
  Against Cascading Events

abstract:
  Load shedding is the last and most expensive control action against system
collapse and blackout. Achievement of an efficient emergency control to
stabilize the power system following severe disturbances, requires two key
objectives. First, preventing of further cascading outages, i.e. saving the
available and determinant power system elements and second, issuing proper
control actions to stabilize the power system inside the permissible time
frame. In this paper online contingency analysis is performed to monitor secure
and reliable operation of transmission lines. Load shedding locations are
continuously updated based on loading rate/thermal limit of lines to prevent
their outage. Simulation of severe contingencies carried out on 39 bus IEEE
standard test system in DIgSILENT power-factory validates the efficiency of
proposed method.


title: Teams in Online Scheduling Polls: Game-Theoretic Aspects

abstract:
  Consider an important meeting to be held in a team-based organization. Taking
availability constraints into account, an online scheduling poll is being used
in order to decide upon the exact time of the meeting. Decisions are to be
taken during the meeting, therefore each team would like to maximize its
relative attendance in the meeting (i.e., the proportional number of its
participating team members). We introduce a corresponding game, where each team
can declare (in the scheduling poll) a lower total availability, in order to
improve its relative attendance---the pay-off. We are especially interested in
situations where teams can form coalitions.
  We provide an efficient algorithm that, given a coalition, finds an optimal
way for each team in a coalition to improve its pay-off. In contrast, we show
that deciding whether such a coalition exists is NP-hard. We also study the
existence of Nash equilibria: Finding Nash equilibria for various small sizes
of teams and coalitions can be done in polynomial time while it is coNP-hard if
the coalition size is unbounded.


title: Nondestructive Detection of Polar Molecules via Rydberg Atoms

abstract:
  A highly sensitive, general, and preferably nondestructive technique to
detect polar molecules would greatly advance a number of fields, in particular
quantum science with cold and ultracold molecules. Here, we propose using
resonant energy transfer between molecules and Rydberg atoms to detect
molecules. Based on an energy transfer cross section of $>10^{-6}\,$cm$^2$ for
sufficiently low collision energies, a near unit efficiency non-destructive
detection of basically any polar molecule species in a well defined internal
state should be possible.


title: The Effect of Gender in the Publication Patterns in Mathematics

abstract:
  Despite the increasing number of women graduating in mathematics, a systemic
gender imbalance persists and is signified by a pronounced gender gap in the
distribution of active researchers and professors. Especially at the level of
university faculty, women mathematicians continue being drastically
underrepresented, decades after the first affirmative action measures have been
put into place. A solid publication record is of paramount importance for
securing permanent positions. Thus, the question arises whether the publication
patterns of men and women mathematicians differ in a significant way. Making
use of the zbMATH database, one of the most comprehensive metadata sources on
mathematical publications, we analyze the scholarly output of ~150,000
mathematicians from the past four decades whose gender we algorithmically
inferred. We focus on development over time, collaboration through
coautorships, presumed journal quality and distribution of research topics --
factors known to have a strong impact on job perspectives. We report
significant differences between genders which may put women at a disadvantage
when pursuing an academic career in mathematics.


title:
$\mathcal O(n)$ working precision inverses for symmetric tridiagonal
  Toeplitz matrices with $\mathcal O(1)$ floating point calculations

abstract:
  A well known numerical task is the inversion of large symmetric tridiagonal
Toeplitz matrices, i.e., matrices whose entries equal $a$ on the diagonal and
$b$ on the extra diagonals ($a, b\in \mathbb R$). The inverses of such matrices
are dense and there exist well known explicit formulas by which they can be
calculated in $\mathcal O(n^2)$. In this note we present a simplification of
the problem that has proven to be rather useful in everyday practice: If $\vert
a\vert > 2\vert b\vert$, that is, if the matrix is strictly diagonally
dominant, its inverse is a band matrix to working precision and the bandwidth
is independent of $n$ for sufficiently large $n$. Employing this observation,
we construct a linear time algorithm for an explicit tridiagonal inversion that
only uses $\mathcal O(1)$ floating point operations. On the basis of this
simplified inversion algorithm we outline the cornerstones for an efficient
parallelizable approximative equation solver.


title: Uniform Information Segmentation

abstract:
  Size uniformity is one of the main criteria of superpixel methods. But size
uniformity rarely conforms to the varying content of an image. The chosen size
of the superpixels therefore represents a compromise - how to obtain the fewest
superpixels without losing too much important detail. We propose that a more
appropriate criterion for creating image segments is information uniformity. We
introduce a novel method for segmenting an image based on this criterion. Since
information is a natural way of measuring image complexity, our proposed
algorithm leads to image segments that are smaller and denser in areas of high
complexity and larger in homogeneous regions, thus simplifying the image while
preserving its details. Our algorithm is simple and requires just one input
parameter - a threshold on the information content. On segmentation comparison
benchmarks it proves to be superior to the state-of-the-art. In addition, our
method is computationally very efficient, approaching real-time performance,
and is easily extensible to three-dimensional image stacks and video volumes.


title:
Chromosphere to 1 AU Simulation of the 2011 March 7th Event: A
  Comprehensive Study of Coronal Mass Ejection Propagation

abstract:
  We perform and analyze results of a global magnetohydrodyanmic (MHD)
simulation of the fast coronal mass ejection (CME) that occurred on 2011 March
7. The simulation is made using the newly developed Alfv\'en Wave Solar Model
(AWSoM), which describes the background solar wind starting from the upper
chromosphere and extends to 24 R$_{\odot}$. Coupling AWSoM to an inner
heliosphere (IH) model with the Space Weather Modeling Framework (SWMF) extends
the total domain beyond the orbit of Earth. Physical processes included in the
model are multi-species thermodynamics, electron heat conduction (both
collisional and collisionless formulations), optically thin radiative cooling,
and Alfv\'en-wave turbulence that accelerates and heats the solar wind. The
Alfv\'en-wave description is physically self-consistent, including
non-Wentzel-Kramers-Brillouin (WKB) reflection and physics-based apportioning
of turbulent dissipative heating to both electrons and protons. Within this
model, we initiate the CME by using the Gibson-Low (GL) analytical flux rope
model and follow its evolution for days, in which time it propagates beyond
STEREO A. A detailed comparison study is performed using remote as well as
\textit{in situ} observations. Although the flux rope structure is not compared
directly due to lack of relevant ejecta observation at 1 AU in this event, our
results show that the new model can reproduce many of the observed features
near the Sun (e.g., CME-driven extreme ultraviolet (EUV) waves, deflection of
the flux rope from the coronal hole, "double-front" in the white light images)
and in the heliosphere (e.g., shock propagation direction, shock properties at
STEREO A).


title: On the Size of Lempel-Ziv and Lyndon Factorizations

abstract:
  Lyndon factorization and Lempel-Ziv (LZ) factorization are both important
tools for analysing the structure and complexity of strings, but their
combinatorial structure is very different. In this paper, we establish the
first direct connection between the two by showing that while the Lyndon
factorization can be bigger than the non-overlapping LZ factorization (which we
demonstrate by describing a new, non-trivial family of strings) it is never
more than twice the size.


title: The time fractional Schr\"odinger equation on Hilbert space

abstract:
  We study the linear fractional Schr\"odinger equation on a Hilbert space,
with a fractional time derivative of order $0<\alpha<1,$ and a self-adjoint
generator $A.$ Using the spectral theorem we prove existence and uniqueness of
strong solutions, and we show that the solutions are governed by an operator
solution family $\{U_{\alpha}(t)\}_{t\geq 0}$. Moreover, we prove that the
solution family $U_{\alpha}(t)$ converges strongly to the family of unitary
operators $e^{-itA},$ as $\alpha$ approaches to $1$.


title: On the Chow Ring of the Stack of truncated Barsotti-Tate Groups

abstract:
  We determine the Chow ring of the stack of truncated displays and more
generally the Chow ring of the stack of G-zips. We also investigate the
pull-back morphism of the truncated display functor. From this we can determine
the Chow ring of the stack of truncated Barsotti-Tate groups over a field of
characteristic p up to p-torsion.


title: The escape problem for mortal walkers

abstract:
  We introduce and investigate the escape problem for random walkers that may
eventually die, decay, bleach, or lose activity during their diffusion towards
an escape or reactive region on the boundary of a confining domain. In the case
of a first-order kinetics (i.e., exponentially distributed lifetimes), we study
the effect of the associated death rate onto the survival probability, the exit
probability, and the mean first passage time. We derive the upper and lower
bounds and some approximations for these quantities. We reveal three asymptotic
regimes of small, intermediate and large death rates. General estimates and
asymptotics are compared to several explicit solutions for simple domains, and
to numerical simulations. These results allow one to account for stochastic
photobleaching of fluorescent tracers in bio-imaging, degradation of mRNA
molecules in genetic translation mechanisms, or high mortality rates of
spermatozoa in the fertilization process. This is also a mathematical ground
for optimizing storage containers and materials to reduce the risk of leakage
of dangerous chemicals or nuclear wastes.


title:
Quantum-limited biochemical magnetometers designed using the Fisher
  information and quantum reaction control

abstract:
  Radical-ion pairs and their reactions have triggered the study of quantum
effects in biological systems. This is because they exhibit a number of effects
best understood within quantum information science, and at the same time are
central in understanding the avian magnetic compass and the spin transport
dynamics in photosynthetic reaction centers. Here we address radical-pair
reactions from the perspective of quantum metrology. Since the coherent spin
motion of radical-pairs is effected by an external magnetic field, these
spin-dependent reactions essentially realize a biochemical magnetometer. Using
the quantum Fisher information, we find the fundamental quantum limits to the
magnetic sensitivity of radical-pair magnetometers. We then explore how well
the usual measurement scheme considered in radical-pair reactions, the
measurement of reaction yields, approaches the fundamental limits. In doing so,
we find the optimal hyperfine interaction Hamiltonian that leads to the best
magnetic sensitivity as obtained from reaction yields. This is still an order
of magnitude smaller than the absolute quantum limit. Finally, we demonstrate
that with a realistic quantum reaction control reminding of Ramsey
interferometry, here presented as a quantum circuit involving the spin-exchange
interaction and a recently proposed molecular switch, we can approach the
fundamental quantum limit within a factor of 2. This work opens the application
of well-advanced quantum metrology methods to biological systems.


title: Should I use TensorFlow

abstract:
  Google's Machine Learning framework TensorFlow was open-sourced in November
2015 [1] and has since built a growing community around it. TensorFlow is
supposed to be flexible for research purposes while also allowing its models to
be deployed productively. This work is aimed towards people with experience in
Machine Learning considering whether they should use TensorFlow in their
environment. Several aspects of the framework important for such a decision are
examined, such as the heterogenity, extensibility and its computation graph. A
pure Python implementation of linear classification is compared with an
implementation utilizing TensorFlow. I also contrast TensorFlow to other
popular frameworks with respect to modeling capability, deployment and
performance and give a brief description of the current adaption of the
framework.


title:
Generating series formulas for the structure constants of Solomon's
  descent algebra

abstract:
  Introduced by Solomon in his 1976 paper, the descent algebra of a finite
Coxeter group received significant attention over the past decades. As proved
by Gessel, in the case of the symmetric group its structure constants give the
comultiplication table for the fundamental basis of quasisymmetric functions.
We show that this property actually implies several well known relations linked
to the Robinson-Schensted-Knuth correspondence and some of its generalisations.
We further use the theory of type B quasisymmetric functions introduced by Chow
to provide analogue results when the Coxeter group is the hyperoctahedral
group.


title:
SISO and SIMO Accompaniment Cancellation for Live Solo Recordings Based
  on Short-Time ERB-Band Wiener Filtering and Spectral Subtraction

abstract:
  Research in collaborative music learning is subject to unresolved problems
demanding new technological solutions. One such problem poses the suppression
of the accompaniment in a live recording of a performance during practice,
which can be for the purposes of self-assessment or further machine-aided
analysis. Being able to separate a solo from the accompaniment allows to create
learning agents that may act as personal tutors and help the apprentice improve
his or her technique. First, we start from the classical adaptive noise
cancelling approach, and adjust it to the problem at hand. In a second step, we
compare some adaptive and Wiener filtering approaches and assess their
performances on the task. Our findings underpin that adaptive filtering is
inapt of dealing with music signals and that Wiener filtering in the short-time
Fourier transform domain is a much more effective approach. In addition, it is
very cheap if carried out in the frequency bands of auditory filters. A
double-output extension based on maximal-ratio combining is also proposed.


title:
Voronoi-based compact image descriptors: Efficient Region-of-Interest
  retrieval with VLAD and deep-learning-based descriptors

abstract:
  We investigate the problem of image retrieval based on visual queries when
the latter comprise arbitrary regions-of-interest (ROI) rather than entire
images. Our proposal is a compact image descriptor that combines the
state-of-the-art in content-based descriptor extraction with a multi-level,
Voronoi-based spatial partitioning of each dataset image. The proposed
multi-level Voronoi-based encoding uses a spatial hierarchical K-means over
interest-point locations, and computes a content-based descriptor over each
cell. In order to reduce the matching complexity with minimal or no sacrifice
in retrieval performance: (i) we utilize the tree structure of the spatial
hierarchical K-means to perform a top-to-bottom pruning for local similarity
maxima; (ii) we propose a new image similarity score that combines relevant
information from all partition levels into a single measure for similarity;
(iii) we combine our proposal with a novel and efficient approach for optimal
bit allocation within quantized descriptor representations. By deriving both a
Voronoi-based VLAD descriptor (termed as Fast-VVLAD) and a Voronoi-based deep
convolutional neural network (CNN) descriptor (termed as Fast-VDCNN), we
demonstrate that our Voronoi-based framework is agnostic to the descriptor
basis, and can easily be slotted into existing frameworks. Via a range of ROI
queries in two standard datasets, it is shown that the Voronoi-based
descriptors achieve comparable or higher mean Average Precision against
conventional grid-based spatial search, while offering more than two-fold
reduction in complexity. Finally, beyond ROI queries, we show that Voronoi
partitioning improves the geometric invariance of compact CNN descriptors,
thereby resulting in competitive performance to the current state-of-the-art on
whole image retrieval.


title:
Statistical Study of Observed and Intrinsic Durations among BATSE and
  Swift/BAT GRBs

abstract:
  Studies of \textit{BATSE} bursts \citep{kouveliotou:93} have resulted in the
widespread adoption of a two-group categorization: long bursts (those with
durations $\geq 2$ seconds) and short bursts (those with durations $\leq 2$
seconds). This categorization, one must recall, used the observed $T_{90}$ time
durations for bursts (during which 90\% of a burst's fluence is measured). In
this work, we have explored two ideas: 1) a statistical search for a possible
third, intermediate category of bursts (between the "short" and the "long"
ones) among 2041 \textit{BATSE} GRBs and 757 \textit{Swift/BAT} ones, 2) a
study of bursts' intrinsic durations, where durations in the bursts' reference
frames (instead of the observed durations) are considered, for this, 248
\textit{Swift/BAT} bursts that have redshift measurements were statistically
analyzed for the same categorization goal.
  We first use a Monte Carlo method to determine the proper binning of each
GRB, considering that bursts come with different uncertainties on their
durations. Then, using the method of minimization of chi-square $\chi^2$, we
search for the best fit of the normalized frequency distributions
$\frac{1}{N_0}\frac{dN}{d\ln{T}}$ of durations, this allows us to compare fits
with two groups ("short" and "long") with fits with three groups ("short",
"long", and "intermediate"). Our results indicate that the distributions of
observed durations are better fitted by three groups than two groups for
\textit{Swift/BAT} data, interestingly, the "intermediate" group appears rather
clearly for both observed and intrinsic durations. For BATSE data, the
statistical test does not prefer three groups over two. We discuss the results,
their possible underlying causes, and reasonable interpretations.


title: "Model and Run" Constraint Networks with a MILP Engine

abstract:
  Constraint Programming (CP) users need significant expertise in order to
model their problems appropriately, notably to select propagators and search
strategies. This puts the brakes on a broader uptake of CP. In this paper, we
introduce MICE, a complete Java CP modeler that can use any Mixed Integer
Linear Programming (MILP) solver as a solution technique. Our aim is to provide
an alternative tool for democratizing the "CP-style" modeling thanks to its
simplicity of use, with reasonable solving capabilities. Our contributions
include new decompositions of (reified) constraints and constraints on
numerical variables.


title: A Homogeneous and Isotropic Universe in Lorentz Gauge Theory of Gravity

abstract:
  Lorentz gauge theory of gravity was recently introduced. We study the
homogeneous and isotropic universe of this theory. It is shown that some time
after the matter in the universe is diluted enough, at $z \sim 0.6$, the
decelerating expansion shifts spontaneously to an accelerating one without a
dark energy. We discuss that Lorentz gauge theory puts no constraint on the
total energy content of the universe at present time and therefore the
magnitude of vacuum energy predicted by field theory is not contradictory
anymore. It is demonstrated that in this theory the limit on the number of
relativistic particles in the universe is much looser than in GR. An
inflationary mechanism is discussed as well. We show that the theory, unlike
GR, does not require the slow-roll or similar conditions to drive the inflation
at the beginning of the universe.


title:
Weiss oscillations and particle-hole symmetry at the half-filled Landau
  level

abstract:
  Particle-hole symmetry in the lowest Landau level of the two-dimensional
electron gas requires the electrical Hall conductivity to equal $\pm e^2/2h$ at
half-filling. We study the consequences of weakly broken particle-hole symmetry
for magnetoresistance oscillations about half-filling in the presence of an
applied periodic one-dimensional electrostatic potential using the Dirac
composite fermion theory proposed by Son. At fixed electron density, the
oscillation minima are asymmetrically biased towards higher magnetic fields,
while at fixed magnetic field, the oscillations occur symmetrically as the
electron density is varied about half-filling. We find an approximate "sum
rule" obeyed for all pairs of oscillation minima that can be tested in
experiment. The locations of the magnetoresistance oscillation minima for the
composite fermion theory of Halperin, Lee, and Read (HLR) and its particle-hole
conjugate agree exactly. Within the current experimental resolution, the
locations of the oscillation minima produced by the Dirac composite fermion
coincide with those of HLR. These results may indicate that all three composite
fermion theories describe the same long wavelength physics.


title: Quantitative strain analysis of InAs/GaAs quantum dot materials

abstract:
  Geometric phase analysis has been applied to high resolution aberration
corrected (scanning) transmission electron microscopy images of InAs/GaAs
quantum dot (QD) materials. We show quantitatively how the lattice mismatch
induced strain varies on the atomic scale and tetragonally distorts the lattice
in a wide region that extends several nanometers into the GaAs spacer layer
below and above the QDs. Finally, we show how V-shaped dislocations originating
at the QD/GaAs interface efficiently remove most of the lattice mismatch
induced tetragonal distortions in and around the QD.


title:
Flow Regimes of Mesoscale Circulations Forced by Inhomogeneous Surface
  Heating

abstract:
  Urbanization is one of the extreme process that increases uncertainty in
future climate projections. Flow regimes of mesoscale circulations associated
with surface heating due to urbanization have been investigated using a wavelet
based computational fluid dynamics~(CFD) model. The results of our numerical
model have been validated against that of a laboratory model, as well as
reference numerical simulations. Characteristics of urban induced circulations
have been studied for surface heat flux perturbation ($H_0$) between
$28.93$Wm$^{-2}$ and $925.92$Wm$^{-2}$, and the results have been analyzed
against available boundary layer measurements under similar physical
conditions. Our primary study shows that urban/rural heat flux anomalies
introduce strong oscillations in the convective boundary layer (CBL), and
transfers a fraction of the turbulent kinetic energy vertically through
internal waves. Such results complement previous investigators' hypothesis that
temporal oscillations in urban-induced mesoscale circulations are primarily due
to a downscale energy cascade. Although a further detailed study is necessary,
the present numerical observations provide useful feedback for the impacts of
urbanization on regional climate.


title: A Simple Model of Attentional Blink

abstract:
  The attentional blink (AB) effect is the reduced ability of subjects to
report a second target stimuli (T2) among a rapidly presented series of
non-target stimuli, when it appears within a time window of about 200-500 ms
after a first target (T1). We present a simple dynamical systems model
explaining the AB as resulting from the temporal response dynamics of a
stochastic, linear system with threshold, whose output represents the amount of
attentional resources allocated to the incoming sensory stimuli. The model
postulates that the available attention capacity is limited by activity of the
default mode network (DMN), a correlated set of brain regions related to task
irrelevant processing which is known to exhibit reduced activation following
mental training such as mindfulness meditation. The model provides a
parsimonious account relating key findings from the AB, DMN and meditation
research literature, and suggests some new testable predictions.


title: Strained GaN Quantum-Well FETs on Single Crystal Bulk AlN Substrates

abstract:
  We report the first realization of molecular beam epitaxy grown strained GaN
quantum well field-effect transistors on single-crystal bulk AlN substrates.
The fabricated double heterostructure FETs exhibit a two- dimensional electron
gas (2DEG) density in excess of 2x10^13/cm2. Ohmic contacts to the 2DEG channel
were formed by n+ GaN MBE regrowth process, with a contact resistance of 0.13
Ohm-mm. Raman spectroscopy using the quantum well as an optical marker reveals
the strain in the quantum well, and strain relaxation in the regrown GaN
contacts. A 65-nm-long rectangular-gate device showed a record high DC drain
current drive of 2.0 A/mm and peak extrinsic transconductance of 250 mS/mm.
Small-signal RF performance of the device achieved current gain cutoff
frequency fT~120 GHz. The DC and RF performance demonstrate that bulk AlN
substrates offer an attractive alternative platform for strained quantum well
nitride transistors for future high-voltage and high-power microwave
applications.


title: Uncolored Random Tensors, Melon Diagrams, and the SYK Models

abstract:
  Certain models with rank-$3$ tensor degrees of freedom have been shown by
Gurau and collaborators to possess a novel large $N$ limit, where $g^2 N^3$ is
held fixed. In this limit the perturbative expansion in the quartic coupling
constant, $g$, is dominated by a special class of "melon" diagrams. We study
"uncolored" models of this type, which contain a single copy of real rank-$3$
tensor. Its three indexes are distinguishable; therefore, the models possess
$O(N)^3$ symmetry with the tensor field transforming in the tri-fundamental
representation. Such uncolored models also possess the large $N$ limit
dominated by the melon diagrams. The quantum mechanics of a real anti-commuting
tensor therefore has a similar large $N$ limit to the model recently introduced
by Witten as an implementation of the Sachdev-Ye-Kitaev (SYK) model which does
not require disorder. Gauging the $O(N)^3$ symmetry in our quantum mechanical
model removes the non-singlet states; therefore, one can search for its
well-defined gravity dual. We point out, however, that the model possesses a
vast number of gauge-invariant operators involving higher powers of the tensor
field, suggesting that the complete gravity dual will be intricate. We also
discuss the quantum mechanics of a complex 3-index anti-commuting tensor, which
has $U(N)^2\times O(N)$ symmetry and argue that it is equivalent in the large
$N$ limit to a version of SYK model with complex fermions. Finally, we discuss
similar models of a commuting tensor in dimension $d$. While the quartic
interaction is not positive definite, we construct the large $N$
Schwinger-Dyson equation for the two-point function and show that its solution
is consistent with conformal invariance. We carry out a perturbative check of
this result using the $4-\epsilon$ expansion.


title:
Geostationary secular dynamics revisited: application to high
  area-to-mass ratio objects

abstract:
  The long-term dynamics of the geostationary Earth orbits (GEO) is revisited
through the application of canonical perturbation theory. We consider a
Hamiltonian model accounting for all major perturbations: geopotential at order
and degree two, lunisolar perturbations with a realistic model for the Sun and
Moon orbits, and solar radiation pressure. The long-term dynamics of the GEO
region has been studied both numerically and analytically, in view of the
relevance of such studies to the issue of space debris or to the disposal of
GEO satellites. Past studies focused on the orbital evolution of objects around
a nominal solution, hereafter called the forced equilibrium solution, which
shows a particularly strong dependence on the area-to-mass ratio. Here, we i)
give theoretical estimates for the long-term behavior of such orbits, and ii)
we examine the nature of the forced equilibrium itself. In the lowest
approximation, the forced equilibrium implies motion with a constant non-zero
average `forced eccentricity', as well as a constant non-zero average
inclination, otherwise known in satellite dynamics as the inclination of the
invariant `Laplace plane'. Using a higher order normal form, we demonstrate
that this equilibrium actually represents not a point in phase space, but a
trajectory taking place on a lower-dimensional torus. We give analytical
expressions for this special trajectory, and we compare our results to those
found by numerical orbit propagation. We finally discuss the use of proper
elements, i.e., approximate integrals of motion for the GEO orbits.


title: Phase vortices of the quenched Haldane Model

abstract:
  Using the recently developed Bloch-state tomography technique, the
quasimomentum $\bf k$-dependent Bloch states ${\left( {\sin \left( {{\theta
_{\mathbf{k}}}/2} \right),\; - \cos \left( {{\theta _{\mathbf{k}}}/2}
\right){e^{i{\phi _{\mathbf{k}}}}}} \right)^T}$ of a two-band tight-binding
model with two sublattices can be mapped out. We show that, if we prepare the
initial Bloch state as the lower-band eigenstate of a topologically trivial
Haldane Hamiltonian $H_i$, and then quench the Haldane Hamiltonian to $H_f$,
the time-dependent azimuthal phase ${\phi _{\mathbf{k}}(t)}$ supports two types
of vortices. The first type of vortices are static, with the corresponding
Bloch vectors pointing to the north pole ($\theta_{\mathbf{k}}=0$). The second
type of vortices are dynamical, with the corresponding Bloch vectors pointing
to the south pole ($\theta_{\mathbf{k}}=\pi$). In the $(k_x,k_y,t)$ space, the
linking number between the trajectories of these two types of vortices equals
exactly to the Chern number of the lower band of $H_f$, which provides an
alternative method to directly map out the topological phase boundaries of the
Haldane model.


title: An evolving model for the supply network in a tourism destination

abstract:
  Tourism is a complex dynamic system including multiple actors which are
related each other composing an evolving social network. This paper presents a
growing bipartite network model that explains the rise of the supply network in
a tourism destination from the beginning phases of development. The nodes are
the lodgings and services in a destination and a link between them appears if a
representative tourist hosted in the lodging visits/consumes the service during
his/her stay. The specific link between both categories are determined by a
random and preferential attachment rule. The analytic results show that the
long-term degree distribution of services follows a shifted power-law
distribution. The numerical simulations show slight disagreements with the
theoretical results in the case of the one-mode degree distribution of
services, due to the low order of convergence to zero of X-motifs. The model
predictions are compared with real data coming from a popular tourist
destination in Gran Canaria, Spain, showing a good agreement between numerical
and empirical data.


title:
Edge waves in plates with resonators: An elastic analogue of the quantum
  valley Hall effect

abstract:
  We investigate elastic periodic structures characterized by topologically
nontrivial bandgaps supporting backscattering suppressed edge waves. These edge
waves are topologically protected and are obtained by breaking inversion
symmetry within the unit cell. Examples for discrete one and two-dimensional
lattices elucidate the concept and illustrate parallels with the quantum valley
Hall effect. The concept is implemented on an elastic plate featuring an array
of resonators arranged according to a hexagonal topology. The resulting
continuous structures have non-trivial bandgaps supporting edge waves at the
interface between two media having different topological invariants. The
topological properties of the considered configurations are predicted by unit
cell and finite strip dispersion analyses. Numerical simulations on finite
structures demonstrate edge wave propagation for excitation at frequencies
belonging to the bulk bandgaps. The considered plate configurations define a
framework for the implementation of topological concepts on continuous elastic
structures of potential engineering relevance.


title: Extremal Restraints for Graph Colourings

abstract:
  A {\em restraint} on a (finite undirected) graph $G = (V,E)$ is a function
$r$ on $V$ such that $r(v)$ is a finite subset of ${\mathbb N}$; a proper
vertex colouring $c$ of $G$ is {\em permitted} by $r$ if $c(v) \not\in r(v)$
for all vertices $v$ of $G$ (we think of $r(v)$ as the set of colours {\em
forbidden} at $v$). Given a large number of colors, for restraints $r$ with
exactly one colour forbidden at each vertex the smallest number of colorings is
permitted when $r$ is a constant function, but the problem of what restraints
permit the largest number of colourings is more difficult. We determine such
extremal restraints for complete graphs and trees.


title:
Estimating volume and surface area of a convex body via its projections
  or sections

abstract:
  The main goal of this paper is to present a series of inequalities connecting
the surface area measure of a convex body and surface area measure of its
projections and sections. We present a solution of a question from S. Campi, P.
Gritzmann and P. Gronchi regarding the asymptotic behavior of the best constant
in a recently proposed reverse Loomis-Whitney inequality. Next we give a new
sufficient condition for the slicing problem to have an affirmative answer, in
terms of the least "outer volume ratio distance" from the class of intersection
bodies of projections of at least proportional dimension of convex bodies.
Finally, we show that certain geometric quantities such as the volume ratio and
minimal surface area (after a suitable normalization) are not necessarily close
to each other.


title:
Different growth rates for spin and superfluid order in a quenched
  spinor condensate

abstract:
  In this paper we study the coarsening dynamics of a spinor condensate
quenched into an easy-axis ferromagnetic phase by a sudden change in the
quadratic Zeeman energy. We show that applying a spin rotation prior to
changing the Zeeman energy accelerates the development of local order and
reduces heating. We examine the longitudinal spin ordering and the superfluid
ordering of the system and show that the respective order parameter correlation
functions exhibit dynamic scaling in the late time dynamics. Our results also
demonstrate that these two types of order grow at different rates, i.e.~with
different dynamic critical exponents. The spin domain area distribution is
calculated and is shown to have power law scaling behavior expected from
percolation theory.


title: A noncommutative discrete potential KdV lift

abstract:
  In this paper, we construct a Grassmann extension of a Yang-Baxter map which
first appeared in [16] and can be considered as a lift of the discrete
potential Korteweg-de Vries (dpKdV) equation. This noncommutative extension
satisfies the Yang-Baxter equation, and it admits a $3 \times 3$ Lax matrix.
Moreover, we show that it can be squeezed down to a system of lattice equations
which possesses a Lax representation and whose bosonic limit is the dpKdV
equation. Finally, we consider commutative analogues of the constructed
Yang-Baxter map and its associated quad-graph system, and we discuss their
integrability.


title:
A wavelet based numerical simulation technique for the two-phase flow
  using the phase field method

abstract:
  In multiphase flow phenomena, bubbles and droplets are advected, deformed,
break up into smaller ones, and coalesce with each other. A primary challenge
of classical computational fluid dynamics (CFD) methods for such flows is to
effectively describe a transition zone between phases across which physical
properties vary steeply but continuously. Based on the van der Waals theory,
Allen-Cahn phase field method describes the face-to-face existence of two
fluids with a free-energy functional of mass density or molar concentration,
without imposing topological constraints on interface as phase boundary. In
this article, a CFD simulation methodology is described by solving the
Allen-Cahn-Navier-Stokes equations using a wavelet collocation method. The
second order temporal accuracy is verified by simulating a moving sharp
interface. The average terminal velocity of a rising gas bubble in a liquid
that is computed by the present method has agreed with that computed by a
laboratory experiment. The calculation of the surface tension force by the
present method also shows an excellent agreement with what was obtained by an
experiment. The up-welling and down-welling disturbances in a Rayleigh-Taylor
instability are computed and compared with that from a reference numerical
simulation. These results show that the wavelet based phase-field method is an
efficient CFD simulation technique for gas-liquid or liquid-liquid flows.


title: The pulse luminosity function of Swift gamma-ray bursts

abstract:
  The complete Swift Burst Alert Telescope and X-Ray Telescope light curves of
118 gamma-ray bursts (GRBs) with known redshifts were fitted using the physical
model of GRB pulses by Willingale et al. to produce a total of 607 pulses. We
compute the pulse luminosity function utilizing three GRB formation rate
models: a progenitor that traces the cosmic star formation rate density (CSFRD)
with either a single population of GRBs, coupled to various evolutionary
parameters, or a bimodal population of high- and low-luminosity GRBs, and a
direct fit to the GRB formation rate excluding any a priori assumptions. We
find that a single population of GRB pulses with an evolving luminosity
function is preferred over all other univariate evolving GRB models, or bimodal
luminosity functions in reproducing the observed GRB pulse L-z distribution and
that the magnitude of the evolution in brightness is consistent with studies
that utilize only the brightest GRB pulses. We determine that the appearance of
a GRB formation rate density evolution component is an artifact of poor
parametrization of the CSFRD at high redshifts rather than indicating evolution
in the formation rate of early epoch GRBs. We conclude that the single
brightest region of a GRB light curve holds no special property, by
incorporating pulse data from the totality of GRB emission we boost the GRB
population statistics by a factor of 5, rule out some models utilized to
explain deficiencies in GRB formation rate modelling, and constrain more
tightly some of the observed parameters of GRB behaviour.


title: Ricci flow, Killing spinors, and T-duality in generalized geometry

abstract:
  We introduce a notion of Ricci flow in generalized geometry, extending a
previous definition by Gualtieri on exact Courant algebroids. Special
stationary points of the flow are given by solutions to first-order
differential equations, the Killing spinor equations, which encompass special
holonomy metrics with solutions of the Hull-Strominger system. Our main result
investigates a method to produce new solutions of the Ricci flow and the
Killing spinor equations. For this, we consider T-duality between possibly
topologically distinct torus bundles endowed with Courant structures, and
demonstrate that solutions of the equations are exchanged under this symmetry.
As applications, we give a mathematical explanation of the dilaton shift in
string theory and prove that the Hull-Strominger system is preserved by
T-duality.


title: High-Multiplicity Election Problems

abstract:
  The computational study of elections generally assumes that the preferences
of the electorate come in as a list of votes. Depending on the context, it may
be much more natural to represent the list succinctly, as the distinct votes of
the electorate and their counts, i.e., high-multiplicity representation. We
consider how this representation affects the complexity of election problems.
High-multiplicity representation may be exponentially smaller than standard
representation, and so many polynomial-time algorithms for election problems in
standard representation become exponential-time. Surprisingly, for
polynomial-time election problems, we are often able to either adapt the same
approach or provide new algorithms to show that these problems remain
polynomial-time in the high-multiplicity case; this is in sharp contrast to the
case where each voter has a weight, where the complexity usually increases. In
the process we explore the relationship between high-multiplicity scheduling
and manipulation of high-multiplicity elections. And we show that for any fixed
set of job lengths, high-multiplicity scheduling on uniform parallel machines
is in P, which was previously known for only two job lengths. We did not find
any natural case where a polynomial-time election problem does not remain in P
when moving to high-multiplicity representation. However, we found one natural
NP-hard election problem where the complexity does increase, namely winner
determination for Kemeny elections.


title: A theory of interpretive clustering in free recall

abstract:
  A stochastic model of short-term verbal memory is proposed, in which the
psychological state of the subject is encoded as the instantaneous position of
a particle diffusing over a semantic graph with a probabilistic structure. The
model is particularly suitable for studying the dependence of free-recall
observables on semantic properties of the words to be recalled. Besides
predicting some well-known experimental features (contiguity effect, forward
asymmetry, word-length effect), a novel prediction is obtained on the
relationship between the contiguity effect and the syllabic length of words;
shorter words, by way of their wider semantic range, are predicted to be
characterized by stronger forward contiguity. A fresh analysis of archival data
allows to confirm this prediction.


title: GnRH induced Phase Synchrony of Coupled Neurons

abstract:
  Gonadotropin-releasing hormone (GnRH) is reported to control mammalian
reproductive processes. GnRH a neurohormone which is pulsatile released into
the pituitary portal blood by hypothalamic GnRH neurons. In the present study,
the phase synchronization among a population of identical neurons subjected to
a pool of coupling molecules GnRH in extracellular medium via mean-field
coupling mechanism is investigated. In the model of populated neurons, GnRH is
considered to be autocrine signaling molecule and is taken to be common to all
neurons to act as synchronizing agent. The rate of synchrony is estimated
qualitatively and quantitatively by measuring phase locking values, time
evolution of the phase differences and recurrence plots. Our numerical results
show a phase transition like behavior separating the synchronized and
desynchronized regimes. We also investigated long range communication or relay
information transfer for one dimensional array of such neurons.


title: Deep attractor network for single-microphone speaker separation

abstract:
  Despite the overwhelming success of deep learning in various speech
processing tasks, the problem of separating simultaneous speakers in a mixture
remains challenging. Two major difficulties in such systems are the arbitrary
source permutation and unknown number of sources in the mixture. We propose a
novel deep learning framework for single channel speech separation by creating
attractor points in high dimensional embedding space of the acoustic signals
which pull together the time-frequency bins corresponding to each source.
Attractor points in this study are created by finding the centroids of the
sources in the embedding space, which are subsequently used to determine the
similarity of each bin in the mixture to each source. The network is then
trained to minimize the reconstruction error of each source by optimizing the
embeddings. The proposed model is different from prior works in that it
implements an end-to-end training, and it does not depend on the number of
sources in the mixture. Two strategies are explored in the test time, K-means
and fixed attractor points, where the latter requires no post-processing and
can be implemented in real-time. We evaluated our system on Wall Street Journal
dataset and show 5.49\% improvement over the previous state-of-the-art methods.


title:
Search for CP violation in t t-bar production and decay in proton-proton
  collisions at sqrt(s) = 8 TeV

abstract:
  The results of a first search for CP violation in the production and decay of
top quark-antiquark (t t-bar) pairs are presented. The search is based on
asymmetries in T-odd, triple-product correlation observables, where T is the
time-reversal operator. The analysis uses a sample of proton-proton collisions
at sqrt(s) = 8 TeV collected by the CMS experiment, corresponding to an
integrated luminosity of 19.7 inverse femtobarns.. Events are selected having
one electron or muon and at least four jets. The T-odd observables are measured
using four-momentum vectors associated with t t-bar production and decay. The
measured asymmetries exhibit no evidence for CP-violating effects, consistent
with the expectation from the standard model.


title: Spherical functions approach to sums of random Hermitian matrices

abstract:
  We present an approach to sums of random Hermitian matrices via the theory of
spherical functions for the Gelfand pair $(\mathrm{U}(n) \ltimes
\mathrm{Herm}(n), \mathrm{U}(n))$. It is inspired by a similar approach of
Kieburg and K\"osters for products of random matrices. The spherical functions
have determinantal expressions because of the Harish-Chandra/Itzykson-Zuber
integral formula. It leads to remarkably simple expressions for the spherical
transform and its inverse. The spherical transform is applied to sums of
unitarily invariant random matrices from polynomial ensembles and the subclass
of polynomial ensembles of derivative type (in the additive sense), which turns
out to be closed under addition. We finally present additional detailed
calculations for the sum with a random matrix from a Laguerre Unitary Ensemble.


title:
Scalar curvature in conformal geometry of Connes-Landi noncommutative
  manifolds

abstract:
  We first propose a conformal geometry for Connes-Landi noncommutative
manifolds and study the associated scalar curvature. The new scalar curvature
contains its Riemannian counterpart as the commutative limit. Similar to the
results on noncommutative two tori, the quantum part of the curvature consists
of actions of the modular derivation through two local curvature functions.
Explicit expressions for those functions are obtained for all even dimensions
(greater than two). In dimension four, the one variable function shows striking
similarity to the analytic functions of the characteristic classes appeared in
the Atiyah-Singer local index formula, namely, it is roughly a product of the
$j$-function (which defines the $\hat A$-class of a manifold) and an
exponential function (which defines the Chern character of a bundle). By
performing two different computations for the variation of the Einstein-Hilbert
action, we obtain a deep internal relations between two local curvature
functions. Straightforward verification for those relations gives a strong
conceptual confirmation for the whole computational machinery we have developed
so far, especially the Mathematica code hidden behind the paper.


title:
Energy decomposition analysis of neutral and negatively charged
  borophenes

abstract:
  The effect of external static charging on borophenes - 2D boron crystals - is
investigated by using first principles calculations. The influence of the
excess negative charge on the stability of the 2D structures is examined using
a very simple analysis of decomposition of the binding energy of a given boron
layer into contributions coming from boron atoms that have different
coordination numbers. This analysis is important to understand how the local
neighbourhood of an atom influences the overall stability of the monolayer
structure. The decomposition is done for the $\alpha$-sheet and its related
family of structures. From this analysis, we have found a preference for 2D
boron crystals with very small or very high charges per atom. The structures
with intermediate charges are energetically not favourable. We have also found
a clear preference in terms of binding energy for the experimentally seen
$\gamma$-sheet and $\delta$-sheet structures that is almost independent on the
considered excess of negative charge of the structures. On the other hand, we
have shown that a model based solely on nearest-neighbour interactions,
although instructive, is too simple to predict binding energies accurately.


title: Size-Dependent Structural Phase Transitions in SrTiO3 Nanoparticles

abstract:
  Understanding the structural phase diagram of nano scale SrTiO3 has important
implications on the basic physics and applications of the general class of
transition metal oxide perovskites. Pressure dependent structural measurements
on monodispersed nanoscale SrTiO3 samples with average diameters of 10 to ~80
nm were conducted. A robust pressure independent polar structure was detected
in the 10 nm sample for pressures of up to 13 GPa while a size dependent cubic
to tetragonal transition occurs (at P = Pc) for larger particle sizes. The
results suggest that the growth of ~10 nm STO particles on substrates with
large lattice mismatch will not alter the polar state of the system for a large
range of strain values, possibly enabling device use.


title:
Differential Private Noise Adding Mechanism and Its Application on
  Consensus

abstract:
  Differential privacy is a formal mathematical {stand-ard} for quantifying the
degree of that individual privacy in a statistical database is preserved. To
guarantee differential privacy, a typical method is adding random noise to the
original data for data release. In this paper, we investigate the conditions of
differential privacy considering the general random noise adding mechanism, and
then apply the obtained results for privacy analysis of the privacy-preserving
consensus algorithm. Specifically, we obtain a necessary and sufficient
condition of $\epsilon$-differential privacy, and the sufficient conditions of
$(\epsilon, \delta)$-differential privacy. We apply them to analyze various
random noises. For the special cases with known results, our theory matches
with the literature; for other cases that are unknown, our approach provides a
simple and effective tool for differential privacy analysis. Applying the
obtained theory, on privacy-preserving consensus algorithms, it is proved that
the average consensus and $\epsilon$-differential privacy cannot be guaranteed
simultaneously by any privacy-preserving consensus algorithm.


title: Epitaxial graphene on SiC: 2D sheets, selective growth and nanoribbons

abstract:
  Epitaxial graphene grown on SiC by the confinement controlled sublimation
method is reviewed, with an emphasis on multilayer and monolayer epitaxial
graphene on the carbon face of 4H-SiC and on directed and selectively grown
structures under growth-arresting or growth-enhancing masks. Recent
developments in the growth of templated graphene nanostructures are also
presented, as exemplified by tens of micron long very well confined and
isolated 20-40nm wide graphene ribbons. Scheme for large scale integration of
ribbon arrays with Si wafer is also presented.


title: Asynchronous Broadcasting with Bivalent Beeps

abstract:
  In broadcasting, one node of a network has a message that must be learned by
all other nodes. We study deterministic algorithms for this fundamental
communication task in a very weak model of wireless communication. The only
signals sent by nodes are beeps. Moreover, they are delivered to neighbors of
the beeping node in an asynchronous way: the time between sending and reception
is finite but unpredictable. We first observe that under this scenario, no
communication is possible, if beeps are all of the same strength. Hence we
study broadcasting in the bivalent beeping model, where every beep can be
either soft or loud. At the receiving end, if exactly one soft beep is received
by a node in a round, it is heard as soft. Any other combination of beeps
received in a round is heard as a loud beep. The cost of a broadcasting
algorithm is the total number of beeps sent by all nodes.
  We consider four levels of knowledge that nodes may have about the network:
anonymity (no knowledge whatsoever), ad-hoc (all nodes have distinct labels and
every node knows only its own label), neighborhood awareness (every node knows
its label and labels of all neighbors), and full knowledge (every node knows
the entire labeled map of the network and the identity of the source). We first
show that in the anonymous case, broadcasting is impossible even for very
simple networks. For each of the other three knowledge levels we provide upper
and lower bounds on the minimum cost of a broadcasting algorithm. Our results
show separations between all these scenarios. Perhaps surprisingly, the jump in
broadcasting cost between the ad-hoc and neighborhood awareness levels is much
larger than between the neighborhood awareness and full knowledge levels,
although in the two former levels knowledge of nodes is local, and in the
latter it is global.


title: Higher Order Reentrant Post Modes in Cylindrical Cavities

abstract:
  Reentrant cavities are microwave resonant devices employed in a number of
different areas of physics. They are appealing due to their simple frequency
tuning mechanism, which offers large tuning ranges. Reentrant cavities are, in
essence, 3D lumped LC circuits consisting of a conducting central post embedded
in a resonant cavity. The lowest order reentrant mode (which transforms from
the $TM_{010}$ mode) has been extensively studied in past publications. In this
work we show the existence of higher order reentrant post modes (which
transform from the $TM_{01n}$ mode family). We characterize these new modes in
terms of their frequency tuning, filling factors and quality factors, as well
as discuss some possible applications of these modes in fundamental physics
tests. The appendix contains a comment on a paper related to this work.


title: Multiscale examination of strain effects in Nd-Fe-B permanent magnets

abstract:
  We have performed a combined first-principles and micromagnetic study on the
strain effects in Nd-Fe-B magnets. First-principles calculations on Nd2Fe14B
reveal that the magnetocrystalline anisotropy (K) is insensitive to the
deformation along c axis and the ab in-plane shrinkage is responsible for the K
reduction. The predicted K is more sensitive to the lattice deformation than
what the previous phenomenological model suggests. The biaxial and triaxial
stress states have a greater impact on K. Negative K occurs in a much wider
strain range in the ab biaxial stress state. Micromagnetic simulations of
Nd-Fe-B magnets using first-principles results show that a 3-4% local strain in
a 2-nm-wide region near the interface around the grain boundaries and triple
junctions leads to a negative local K and thus decreases the coercivity by
~60%. The local ab biaxial stress state is more likely to induce a large loss
of coercivity. In addition to the local stress states and strain levels
themselves, the shape of the interfaces and the intergranular phases also makes
a difference in determining the coercivity. Smoothing the edge and reducing the
sharp angle of the triple regions in Nd-Fe-B magnets would be favorable for a
coercivity enhancement.


title: Graphene Contacts to a HfSe2/SnS2 Heterostructure

abstract:
  Placing graphene on SnS2 results in significant charge transfer, on the order
of 10^13/cm^2, from the graphene to the SnS2, and the charge transfer results
in a negative Schottky barrier contact for electron injection from the graphene
into the SnS2 conduction band. However, due to the s-px,y composition of the
SnS2 conduction band, the coupling between the SnS2 and the graphene is
relatively weak. A third layer, HfSe2, placed between the SnS2 and the
graphene, serves as a matrix element matching layer, since it has strong
coupling to both the graphene and the SnS2. It increases the coupling to the
graphene by a factor of 10, and it has little effect on the negative Schottky
barrier height, since the conduction band wavefucntion of the SnS2 / HfSe2 is a
coherent superposition of the orbitals from the two individual layers, such
that there is no energy barrier for an electron to move between the two layers.
This paper first investigates the electronic properties of the heterostructure
bilayer SnS2 / HfSe2 in the presence of an applied vertical electric field, and
then it investigates the trilayer systems of BN / SnS2 / HfSe2 and graphene /
SnS2 / HfSe2. A tunneling Hamiltonian estimate of the the contact resistance of
the graphene to the SnS2 / HfSe2 heterostructure indicates an excellent
low-resistance contact.


title: The BIN_COUNTS Constraint: Filtering and Applications

abstract:
  We introduce the BIN_COUNTS constraint, which deals with the problem of
counting the number of decision variables in a set which are assigned values
that lie in given bins. We illustrate a decomposition and a filtering algorithm
that achieves generalised arc consistency. We contrast the filtering power of
these two approaches and we discuss a number of applications. We show that
BIN_COUNTS can be employed to develop a decomposition for the $\chi^2$ test
constraint, a new statistical constraint that we introduce in this work. We
also show how this new constraint can be employed in the context of the
Balanced Academic Curriculum Problem and of the Balanced Nursing Workload
Problem. For both these problems we carry out numerical studies involving our
reformulations. Finally, we present a further application of the $\chi^2$ test
constraint in the context of confidence interval analysis.


title:
Digging deeper: Observing primordial gravitational waves below the
  binary black hole produced stochastic background

abstract:
  The merger rate of black hole binaries inferred from the detections in the
first Advanced LIGO science run, implies that a stochastic background produced
by a cosmological population of mergers will likely mask the primordial
gravitational-wave background. Here we demonstrate that the next generation of
ground-based detectors, such as the Einstein Telescope and Cosmic Explorer,
will be able to observe binary black hole mergers throughout the universe with
sufficient efficiency that the confusion background can potentially be
subtracted to observe the primordial background at the level of
$\Omega_{\mathrm{GW}} \simeq 10^{-13}$ after five years of observation.


title: Nonparametric General Reinforcement Learning

abstract:
  Reinforcement learning (RL) problems are often phrased in terms of Markov
decision processes (MDPs). In this thesis we go beyond MDPs and consider RL in
environments that are non-Markovian, non-ergodic and only partially observable.
Our focus is not on practical algorithms, but rather on the fundamental
underlying problems: How do we balance exploration and exploitation? How do we
explore optimally? When is an agent optimal? We follow the nonparametric
realizable paradigm.
  We establish negative results on Bayesian RL agents, in particular AIXI. We
show that unlucky or adversarial choices of the prior cause the agent to
misbehave drastically. Therefore Legg-Hutter intelligence and balanced Pareto
optimality, which depend crucially on the choice of the prior, are entirely
subjective. Moreover, in the class of all computable environments every policy
is Pareto optimal. This undermines all existing optimality properties for AIXI.
However, there are Bayesian approaches to general RL that satisfy objective
optimality guarantees: We prove that Thompson sampling is asymptotically
optimal in stochastic environments in the sense that its value converges to the
value of the optimal policy. We connect asymptotic optimality to regret given a
recoverability assumption on the environment that allows the agent to recover
from mistakes. Hence Thompson sampling achieves sublinear regret in these
environments.
  Our results culminate in a formal solution to the grain of truth problem: A
Bayesian agent acting in a multi-agent environment learns to predict the other
agents' policies if its prior assigns positive probability to them (the prior
contains a grain of truth). We construct a large but limit computable class
containing a grain of truth and show that agents based on Thompson sampling
over this class converge to play Nash equilibria in arbitrary unknown
computable multi-agent environments.


title: Learning a Natural Language Interface with Neural Programmer

abstract:
  Learning a natural language interface for database tables is a challenging
task that involves deep language understanding and multi-step reasoning. The
task is often approached by mapping natural language queries to logical forms
or programs that provide the desired response when executed on the database. To
our knowledge, this paper presents the first weakly supervised, end-to-end
neural network model to induce such programs on a real-world dataset. We
enhance the objective function of Neural Programmer, a neural network with
built-in discrete operations, and apply it on WikiTableQuestions, a natural
language question-answering dataset. The model is trained end-to-end with weak
supervision of question-answer pairs, and does not require domain-specific
grammars, rules, or annotations that are key elements in previous approaches to
program induction. The main experimental result in this paper is that a single
Neural Programmer model achieves 34.2% accuracy using only 10,000 examples with
weak supervision. An ensemble of 15 models, with a trivial combination
technique, achieves 37.7% accuracy, which is competitive to the current
state-of-the-art accuracy of 37.1% obtained by a traditional natural language
semantic parser.


title:
Exponential Separation of Quantum Communication and Classical
  Information

abstract:
  We exhibit a Boolean function for which the quantum communication complexity
is exponentially larger than the classical information complexity. An
exponential separation in the other direction was already known from the work
of Kerenidis et. al. [SICOMP 44, pp. 1550-1572], hence our work implies that
these two complexity measures are incomparable. As classical information
complexity is an upper bound on quantum information complexity, which in turn
is equal to amortized quantum communication complexity, our work implies that a
tight direct sum result for distributional quantum communication complexity
cannot hold. The function we use to present such a separation is the Symmetric
k-ary Pointer Jumping function introduced by Rao and Sinha [ECCC TR15-057],
whose classical communication complexity is exponentially larger than its
classical information complexity. In this paper, we show that the quantum
communication complexity of this function is polynomially equivalent to its
classical communication complexity. The high-level idea behind our proof is
arguably the simplest so far for such an exponential separation between
information and communication, driven by a sequence of round-elimination
arguments, allowing us to simplify further the approach of Rao and Sinha.
  As another application of the techniques that we develop, we give a simple
proof for an optimal trade-off between Alice's and Bob's communication while
computing the related Greater-Than function on n bits: say Bob communicates at
most b bits, then Alice must send n/exp(O(b)) bits to Bob. This holds even when
allowing pre-shared entanglement. We also present a classical protocol
achieving this bound.


title: Navigable videos for presenting scientific data on head-mounted displays

abstract:
  Immersive, stereoscopic viewing enables scientists to better analyze the
spatial structures of visualized physical phenomena. However, their findings
cannot be properly presented in traditional media, which lack these core
attributes. Creating a presentation tool that captures this environment poses
unique challenges, namely related to poor viewing accessibility. Immersive
scientific renderings often require high-end equipment, which can be
impractical to obtain. We address these challenges with our authoring tool and
navigational interface, which is designed for affordable head-mounted displays.
With the authoring tool, scientists can show salient data features as connected
360{\deg} video paths, resulting in a "choose-your-own-adventure" experience.
Our navigational interface features bidirectional video playback for added
viewing control when users traverse the tailor-made content. We evaluate our
system's benefits by authoring case studies on several data sets and conducting
a usability study on the navigational interface's design. In summary, our
approach provides scientists an immersive medium to visually present their
research to the intended audience--spanning from students to colleagues--on
affordable virtual reality headsets.


title: No crisis should go to waste

abstract:
  The crisis in the reproducibility of experiments invites a re-evaluation of
methods of inquiry and validation procedures. The text challenges current
assumptions of knowledge acquisition and introduces G-complexity for defining
decidable vs. non-decidable knowledge domains. A "second Cartesian revolution"
should result in scientific methods that transcend determinism and
reductionism.


title: Polaronic quantum diffusion in dynamic localization regime

abstract:
  We investigate the quantum dynamics in a disordered electronic lattice with
Fibonacci sequence of site energy and off-diagonal electron-phonon coupling
within a sub-Ohmic bath by the time-dependent density matrix renormalization
group algorithm. It is found that, the slope of the inverse participation ratio
versus the coupling strength undergoes a sudden change indicating a transition
from the static to the dynamic localization. In the dynamic localization
regime, the generated polarons coherently diffuse via hopping-like processes
evidenced by the saturated entanglement entropy, providing a novel scenario for
the transportation mechanism in strongly disordered systems. The mean-square
displacement is revealed to be insensitive to the coupling strength, implying
the quantum diffusion behavior survives the energy disorder that prevails in
real organic materials.


title: A geometrical view of scalar modulation instability

abstract:
  We present a novel approach to the analysis of a full model of scalar
modulation instability (MI) by means of a simple geometrical description in the
power vs. frequency plane. This formulation allows to relate the shape of the
MI gain to any arbitrary dispersion profile of the medium. As a result, we
derive a straightforward explanation of the non-trivial dependence of the
cutoff power on high-order dispersion and obtain explicitly the power that
maximizes the gain. Our approach puts forth a powerful tool to synthesize a
desired MI gain with the potential application to a vast number of
parametric-amplification and supercontinuum-generation devices whose
functioning relies upon modulation instability.


title:
Distributed Estimation for Adaptive Networks Based on Serial-Inspired
  Diffusion

abstract:
  Distributed estimation and processing in networks modeled by graphs have
received a great deal of interest recently, due to the benefits of
decentralised processing in terms of performance and robustness to
communications link failure between nodes of the network. Diffusion-based
algorithms have been demonstrated to be among the most effective for
distributed signal processing problems, through the combination of local node
estimate updates and sharing of information with neighbour nodes through
diffusion. In this work, we develop a serial-inspired approach based on
message-passing strategies that provides a significant improvement in
performance over prior art. The concept of serial processing in the graph has
been successfully applied in sum-product based algorithms and here provides
inspiration for an algorithm which makes use of the most up-to-date information
in the graph in combination with the diffusion approach to offer improved
performance.


title:
Standing waves with a critical frequency for nonlinear Choquard
  equations

abstract:
  In this paper, we study the nonlocal Choquard equation $$ -\varepsilon^2
\Delta u_\varepsilon + V u_\varepsilon= (I_\alpha *
|u_\varepsilon|^p)|u_\varepsilon|^{p-2}u_\varepsilon $$ where $N\geq 1$,
$I_\alpha$ is the Riesz potential of order $\alpha \in (0, N)$ and
$\varepsilon>0$ is a parameter. When the nonnegative potential $V\in C
(\mathbb{R}^N)$ achieves $0$ with a homogeneous behaviour or on the closure of
an open set but remains bounded away from $0$ at infinity, we show the
existence of groundstate solutions for small $\varepsilon>0$ and exhibit the
concentration behaviour as $\varepsilon\to 0$.


title: Note on a Paper by Ooguri and Vafa

abstract:
  In a recent paper, Ooguri and Vafa [arXiv:1610.04564] argued that a mild
extension of the Weak Gravity conjecture\cite{weakgrav} led to the conclusion
that the only models of quantum gravity in AdS space with "radius large
compared to the string scale" were models with exact AdS-SUSY. This note
clarifies certain obscure parts of their argument by reinterpreting it as a
statement about brane configurations in flat space. In that context the
statement is that stable non-supersymmetric configurations of branes are
characterized by charges in the torsion subgroup of K-theory and their only
long range fields are gravitational and scalar. The field equations do not have
large radius near horizon AdS solutions. Instead the horizons are Schwarzschild
black branes. This leads us to conjecture that for $d \leq 11$ the K theory
charges are bounded by a small integer, and there can be no large gravitational
back reaction in the near horizon limit, for stable configurations. Unbounded
values of these discrete charges would violate the Covariant Entropy Bound. We
discuss a counterexample to the conjecture in $AdS_3$. We find similar
counterexamples in higher dimensional AdS spaces, but argue that none of them
lead to SUSY violating models of quantum gravity in Minkowski space.