title:
Networked Traffic State Estimation Involving Mixed Fixed-mobile Sensor
  Data Using Hamilton-Jacobi equations

abstract:
  Nowadays, traffic management has become a challenge for urban areas, which
are covering larger geographic spaces and facing the generation of different
kinds of traffic data. This article presents a robust traffic estimation
framework for highways modeled by a system of Lighthill Whitham Richards
equations that is able to assimilate different sensor data available. We first
present an equivalent formulation of the problem using a Hamilton-Jacobi
equation. Then, using a semi-analytic formula, we show that the model
constraints resulting from the Hamilton-Jacobi equation are linear ones. We
then pose the problem of estimating the traffic density given incomplete and
inaccurate traffic data as a Mixed Integer Program. We then extend the density
estimation framework to highway networks with any available data constraint and
modeling junctions. Finally, we present a travel estimation application for a
small network using real traffic measurements obtained obtained during Mobile
Century traffic experiment, and comparing the results with ground truth data.


title: Automatic Genre and Show Identification of Broadcast Media

abstract:
  Huge amounts of digital videos are being produced and broadcast every day,
leading to giant media archives. Effective techniques are needed to make such
data accessible further. Automatic meta-data labelling of broadcast media is an
essential task for multimedia indexing, where it is standard to use multi-modal
input for such purposes. This paper describes a novel method for automatic
detection of media genre and show identities using acoustic features, textual
features or a combination thereof. Furthermore the inclusion of available
meta-data, such as time of broadcast, is shown to lead to very high
performance. Latent Dirichlet Allocation is used to model both acoustics and
text, yielding fixed dimensional representations of media recordings that can
then be used in Support Vector Machines based classification. Experiments are
conducted on more than 1200 hours of TV broadcasts from the British
Broadcasting Corporation (BBC), where the task is to categorise the broadcasts
into 8 genres or 133 show identities. On a 200-hour test set, accuracies of
98.6% and 85.7% were achieved for genre and show identification respectively,
using a combination of acoustic and textual features with meta-data.


title:
Four-wave mixing parametric oscillation and frequency comb generation at
  visible wavelengths in a silica microbubble resonator

abstract:
  Frequency comb generation in microresonators at visible wavelengths has found
applications in a variety of areas such as metrology, sensing, and imaging. To
achieve Kerr combs based on four-wave mixing in a microresonator, dispersion
must be in the anomalous regime. In this work, we demonstrate dispersion
engineering in a microbubble resonator (MBR) fabricated by a two-CO$_2$ laser
beam technique. By decreasing the wall thickness of the MBR down to 1.4 $\mu$m,
the zero dispersion wavelength shifts to values shorter than 764 nm, making
phase matching possible around 765 nm. With the optical \textit{Q}-factor of
the MBR modes being greater than $10^7$, four-wave mixing is observed at 765 nm
for a pump power of 3 mW. By increasing the pump power, parametric oscillation
is achieved, and a frequency comb with 14 comb lines is generated at visible
wavelengths.


title: WordNet2Vec: Corpora Agnostic Word Vectorization Method

abstract:
  A complex nature of big data resources demands new methods for structuring
especially for textual content. WordNet is a good knowledge source for
comprehensive abstraction of natural language as its good implementations exist
for many languages. Since WordNet embeds natural language in the form of a
complex network, a transformation mechanism WordNet2Vec is proposed in the
paper. It creates vectors for each word from WordNet. These vectors encapsulate
general position - role of a given word towards all other words in the natural
language. Any list or set of such vectors contains knowledge about the context
of its component within the whole language. Such word representation can be
easily applied to many analytic tasks like classification or clustering. The
usefulness of the WordNet2Vec method was demonstrated in sentiment analysis,
i.e. classification with transfer learning for the real Amazon opinion textual
dataset.


title:
Solution for the nonlinear relativistic harmonic oscillator via
  Laplace-Adomian decomposition method

abstract:
  Far as we know there are not exact solutions to the equation of motion for a
relativistic harmonic oscillator. In this paper, the relativistic harmonic
oscillator equation which is a nonlinear ordinary differential equation is
studied by means of a combined use of the Adomian Decomposition Method and the
Laplace Transform (LADM). The results that we have obtained, a series of powers
of functions, have never been reported and show a very good match when compared
with other approximate solutions, obtained by different methods. The method
here proposed works with high degree of accuracy and because it requires less
computational effort, it is very convenient to solve this kind of nonlinear
differential equations.


title: Excitonic properties of semiconducting monolayer and bilayer MoTe2

abstract:
  MoTe2 belongs to the semiconducting transition metal dichalcogenide family
with some properties differing from the other well-studied members
(Mo,W)(S,Se)2. The optical band gap is in the near infrared region and both
monolayers and bilayers may have a direct optical band gap. We first simulate
the band structure of both monolayer and bilayer MoTe2 with DFT-GW
calculations. We find a direct (indirect) electronic band gap for the monolayer
(bilayer). By solving the Bethe-Salpeter equation, we calculate similar
energies for the direct excitonic states in monolayer and bilayer. We then
study the optical properties by means of photoluminescence (PL) excitation,
time-resolved PL and power dependent PL spectroscopy. We identify the same
energy for the B exciton state in monolayer and bilayer. Following circularly
polarized excitation, we do not find any exciton polarization for a large range
of excitation energies. At low temperature (T=10 K), we measure similar PL
decay times of the order of 4 ps for both monolayer and bilayer excitons with a
slightly longer one for the bilayer. Finally, we observe a reduction of the
exciton-exciton annihilation contribution to the non-radiative recombination in
bilayer.


title:
High-Fidelity and Ultrafast Initialization of a Hole Spin Bound to a Te
  Isoelectronic Center in ZnS

abstract:
  We demonstrate the optical initialization of a hole-spin qubit bound to an
isoelectronic center (IC) formed by a pair of Te impurities in ZnSe, an
impurity/host system providing high optical homogeneity, large electric dipole
moments, and long coherence times. The initialization scheme is based on the
spin-preserving tunneling of a resonantly excited donor-bound exciton to a
positively charged Te IC, thus forming a positive trion. The radiative decay of
the trion within less than 50 ps leaves a heavy hole in a well-defined
polarization-controlled spin state. The initialization fidelity exceeds 98:5 %
for an initialization time of less than 150 ps.


title:
Enhanced Spin-Flip Scattering by Surface Roughness in WS$_2$ and MoS$_2$
  Armchair Nanoribbons

abstract:
  The band structures of single-layer MoS$_2$ and WS$_2$ present a coupling
between spin and valley degrees of freedom that suppresses spin-flip scattering
and spin dephasing. Here we show that out-of-plane deformations, such as
corrugations or ripples, enhance spin-flip scattering in armchair MoS$_2$ and
WS$_2$ nanoribbons. Spin transport in the presence of surface roughness is
systematically investigated, employing the non-equilibrium Green's function
method along with the tight-binding approximation. Both transmission and
conductance have been calculated as a function of surface roughness. Our
results indicate that the spin-flip rate, usually neglected in flat pristine
samples, increases significantly with the surface roughness amplitude. These
results are important for the design and fabrication of transition metal
dichalcogenides based spintronic devices.


title:
Sparse domination on non-homogeneous spaces with an application to $A_p$
  weights

abstract:
  We extend Lerner's recent approach to sparse domination of
Calder\'on--Zygmund operators to upper doubling (but not necessarily doubling),
geometrically doubling metric measure spaces. Our domination theorem is
different from the one obtained recently by Conde-Alonso and Parcet and yields
a weighted estimate with the sharp power $\max(1,1/(p-1))$ of the $A_p$
characteristic of the weight.


title: On Quantum Microstates in the Near Extremal, Near Horizon Kerr Geometry

abstract:
  We study the thermodynamics of near horizon near extremal Kerr (NHNEK)
geometry within the framework of $AdS_2/CFT_1$ correspondence. We start by
shifting the horizon of near horizon extremal Kerr (NHEK) geometry by a general
finite mass. While this shift does not alter the geometry in that the resulting
classical solution is still diffeomorphic to the NHEK solution, it does lead to
a quantum theory different from that of NHEK. We obtain this quantum theory by
means of a Robinson-Wilczek two-dimensional Kaluza-Klein reduction which
enables us to introduce a finite regulator on the $AdS_2$ boundary and compute
the full asymptotic symmetry group of the two-dimensional quantum conformal
field theory on the respective $AdS_2$ boundary. The s-wave contribution of the
energy-momentum-tensor of this conformal field theory, together with the
asymptotic symmetries, generate a Virasoro algebra with a calculable center,
which agrees with the standard Kerr/$CFT$ result, and a non-vanishing lowest
Virasoro eigenmode. The central charge and lowest eigenmode produce the
Bekenstein-Hawking entropy and Hawking temperature for NHNEK.


title:
Isoperimetric problem for exponential measure on the plane with
  l_1-metric

abstract:
  We give a solution to the isoperimetric problem for the exponential measure
on the plane with the $\ell_1$-metric. As it turns out, among all sets of a
given measure, the simplex or its complement (i.e. the ball in the
$\ell_1$-metric or its complement) has the smallest boundary measure. The proof
is based on a symmetrisation (along the sections of equal $\ell_1$-distance
from the origin).


title:
Consistency relation and inflaton field redefinition in the delta N
  formalism

abstract:
  We compute for general single-field inflation the intrinsic non-Gaussianity
due to the self-interactions of the inflaton field in the squeezed limit. We
recover the consistency relation in the context of the delta N formalism, and
argue that there is a particular field redefinition that makes the intrinsic
non-Gaussianity vanishing, thus improving the estimate of the local
non-Gaussianity using the delta N formalism.


title:
A remark on Liao and Rams' result on distribution of the leading partial
  quotient with growing speed $e^{n^{1/2}}$ in continued fractions

abstract:
  For a real $x\in(0,1)\setminus\mathbb{Q}$, let $x=[a_1(x),a_2(x),\cdots]$ be
its continued fraction expansion. Denote by $T_n(x):= max \{a_k(x): 1\leq k\leq
n\}$ the leading partial quotient up to $n$. For any real $\alpha\in(0,\infty),
\gamma\in(0,\infty)$, let $F(\gamma,\alpha):=\{x\in(0,1)\setminus\mathbb{Q}:
\lim_{n\rightarrow\infty}\frac{T_n(x)}{e^{n^\gamma}}=\alpha\}$. For a set
$E\subset (0,1)\setminus\mathbb{Q}$, let $dim_H E$ be its Hausdorff dimension.
Recently Lingmin Liao and Michal Rams [LR, Theorem 1.3] show that $dim_H
F(\gamma,\alpha)$ is $1$ if $r\in(0,1/2)$, it is $1/2$ if $r\in(1/2,\infty)$
for any $\alpha\in(0,\infty)$. In this paper we show that $dim_H
F(1/2,\alpha)=1/2$ for any $\alpha\in(0,\infty)$ following Liao and Rams'
method, which supplements their result.


title: Radii in the $sd$ shell and the $s_{1/2}$ "halo" orbit: A game changer

abstract:
  Proton radii of nuclei in the $sd$ shell depart appreciably from the
asymptotic law, $\rho_{\pi}=\rho_0A^{1/3}$. The departure exhibits systematic
trends fairly well described by a single phenomenological term in the
Duflo-Zuker formulation, which also happens to explain the sudden increase in
slope in the isotope shifts of several chains at neutron number $N=28$. It was
recently shown that this term is associated with the abnormally large size of
the $s_{1/2}$ and $p$ orbits in the $sd$ and $pf$ shells respectively. Further
to explore the problem, we propose to calculate microscopically radii in the
former. Since the (square) radius is basically a one body operator, its
evolution is dictated by single particle occupancies determined by shell model
calculations. Assuming that the departure from the asymptotic form is entirely
due to the $s_{1/2}$ orbit, the expectation value $\langle
s_{1/2}|r^2|s_{1/2}\rangle$ is determined by demanding that its evolution be
such as to describe well nuclear radii. It does, for an orbit that remains very
large (about 1.6 fm bigger than its $d$ counterparts) up to $N,\,Z=14$ then
drops abruptly but remains some 0.6 fm larger than the $d$ orbits. An
unexpected behavior bound to challenge our understanding of shell formation.


title:
Weil representations of $U(n,n)(\mathbb{F}_{q^2}/\mathbb{F}_q)$, $q>3$
  odd via presentation and compatibility of methods

abstract:
  In this article we construct Weil representations of quasi-split unitary
groups $U(n,n)(\mathbb{F}_{q^2}/\mathbb{F}_q)$ associated to quadratic
extensions of finite fields. We define these representations by using an
adequate presentation Bruhat like of those groups. More precisely, we define
Weil representations of $U(n,n)(\mathbb{F}_{q^2}/\mathbb{F}_q)$ associating to
each generator a linear map of a suitable $\mathbb{C}$-vector space satisfying
the relations of the aforementioned presentation. In addition, we also address
the natural question on the compatibility of our representation of
$U(n,n)(\mathbb{F}_{q^2}/\mathbb{F}_q)$ with the classical one constructed by
G\'erardin.


title: Evaluating balance on social networks from their simple cycles

abstract:
  Signed networks have long been used to represent social relations of amity
(+) and enmity (-) between individuals. Group of individuals who are cyclically
connected are said to be balanced if the number of negative edges in the cycle
is even and unbalanced otherwise. In its earliest and most natural formulation,
the balance of a social network was thus defined from its simple cycles, cycles
which do not visit any vertex more than once. Because of the inherent
difficulty associated with finding such cycles on very large networks, social
balance has since then been studied via other means. In this article we present
the balance as measured from the simple cycles and primitive orbits of social
networks. We specifically provide two measures of balance: the proportion
$R_\ell$ of negative simple cycles of length $\ell$ for each $\ell\leq 20$
which generalises the triangle index, and a ratio $K_\ell$ which extends the
relative signed clustering coefficient introduced by Kunegis. To do so, we use
a Monte Carlo implementation of a novel exact formula for counting the simple
cycles on any weighted directed graph. Our method is free from the
double-counting problem affecting previous cycle-based approaches, does not
require edge-reciprocity of the underlying network, provides a gray-scale
measure of balance for each cycle length separately and is sufficiently
tractable that it can be implemented on a standard desktop computer. We observe
that social networks exhibit strong inter-edge correlations favouring balanced
situations and we determine the corresponding correlation length $\xi$. For
longer simple cycles, $R_\ell$ undergoes a sharp transition to values expected
from an uncorrelated model. This transition is absent from synthetic random
networks, strongly suggesting that it carries a sociological meaning warranting
further research.


title: A new strategy for Robbins' problem of optimal stopping

abstract:
  In this article we study the expected rank problem under full information.
Our approach uses the planar Poisson approach from Gnedin (2007) to derive the
expected rank of a stopping rule that is one of the simplest non-trivial
examples combining rank dependent rules with threshold rules. This rule attains
an expected rank lower than the best upper bounds obtained in the literature so
far, in particular we obtain an expected rank of 2.32614.


title: Shedding light on the black hole mass spectrum

abstract:
  The mass spectrum of stellar black holes (BHs) is highly uncertain.
Theoretical models of BH formation strongly depend on the efficiency of stellar
winds of the progenitor star and on the supernova (SN) explosion mechanism. We
discuss the BH mass spectrum we obtain using SEVN, a new public
population-synthesis code that includes up-to-date stellar-wind prescriptions
and several SN explosion models. Our models indicate a sub-solar metallicity
environment for the progenitors of the gravitational wave source GW150914. We
show that our models predict substantially larger BH masses (up to ~100 Msun)
than other population synthesis codes, at low metallicity. In this proceeding,
we also discuss the impact of pair-instability SNe on our previously published
models.


title: Dynamical scales for multi-TeV top-pair production at the LHC

abstract:
  We calculate all major differential distributions with stable top-quarks at
the LHC. The calculation covers the multi-TeV range that will be explored
during LHC Run II and beyond. Our results are in the form of high-quality
binned distributions. We offer predictions based on three different parton
distribution function (pdf) sets. In the near future we will make our results
available also in the more flexible fastNLO format that allows fast
re-computation with any other pdf set. In order to be able to extend our
calculation into the multi-TeV range we have had to derive a set of dynamic
scales. Such scales are selected based on the principle of fastest perturbative
convergence applied to the differential and inclusive cross-section. Many
observations from our study are likely to be applicable and useful to other
precision processes at the LHC. With scale uncertainty now under good control,
pdfs arise as the leading source of uncertainty for TeV top production. Based
on our findings, true precision in the boosted regime will likely only be
possible after new and improved pdf sets appear. We expect that LHC top-quark
data will play an important role in this process.


title: Using the "Freshman's Dream" to Prove Combinatorial Congruences

abstract:
  In a recent beautiful but technical article, William Y.C. Chen, Qing-Hu Hou,
and Doron Zeilberger developed an algorithm for finding and proving congruence
identities (modulo primes) of indefinite sums of many combinatorial sequences,
namely those (like the Catalan and Motzkin sequences) that are expressible in
terms of constant terms of powers of Laurent polynomials. We first give a
leisurely exposition of their elementary but brilliant approach, and then
extend it in two directions. The Laurent polynomials may be of several
variables, and instead of single sums we have multiple sums. In fact we even
combine these two generalizations! We conclude with some super-challenges.
  In this version we report that Roberto Tauraso pointed out that all our
conjectured super-congruences, at the end of our article are already known,
except one, for which he supplied a beautiful proof that can be found here:
arXiv:1606.05543.


title: Conditional Generation and Snapshot Learning in Neural Dialogue Systems

abstract:
  Recently a variety of LSTM-based conditional language models (LM) have been
applied across a range of language generation tasks. In this work we study
various model architectures and different ways to represent and aggregate the
source information in an end-to-end neural dialogue system framework. A method
called snapshot learning is also proposed to facilitate learning from
supervised sequential signals by applying a companion cross-entropy objective
function to the conditioning vector. The experimental and analytical results
demonstrate firstly that competition occurs between the conditioning vector and
the LM, and the differing architectures provide different trade-offs between
the two. Secondly, the discriminative power and transparency of the
conditioning vector is key to providing both model interpretability and better
performance. Thirdly, snapshot learning leads to consistent performance
improvements independent of which architecture is used.


title: Strain pattern in supercooled liquids

abstract:
  Investigations of strain correlations at the glass transition reveal
unexpected phenomena. The shear strain fluctuations show an Eshelby-strain
pattern ($\,\sim \cos{(4\theta)}/r^2\,$), characteristic for elastic response,
even in liquids at long times [1]. We address this using a mode-coupling theory
for the strain fluctuations in supercooled liquids and data from both, video
microscopy of a two-dimensional colloidal glass former and simulations of
Brownian hard disks. We show that long-ranged and long-lived strain-signatures
follow a scaling law valid close to the glass transition. For large enough
viscosities, the Eshelby-strain pattern is visible even on time scales longer
than the structural relaxation time $\tau$ and after the shear modulus has
relaxed to zero.


title: Quantum decoherence dynamics of divacancy spins in silicon carbide

abstract:
  Long coherence times are key to the performance of quantum bits (qubits).
Here, we experimentally and theoretically show that the Hahn-echo coherence
time (T2) of electron spins associated with divacancy defects in 4H-SiC reaches
1.3 ms, one of the longest T2 times of an electron spin in a naturally isotopic
crystal. Using a first-principles microscopic quantum-bath model, we find that
two factors determine the unusually robust coherence. First, in the presence of
moderate magnetic fields (300 G and above), the 29Si and 13C paramagnetic
nuclear spin baths are decoupled. In addition, because SiC is a binary crystal,
homo-nuclear spin pairs are both diluted and forbidden from forming strongly
coupled, nearest-neighbor spin pairs. Longer neighbor distances result in fewer
nuclear spin flip-flops, a less fluctuating intra-crystalline magnetic
environment, and thus a longer T2 time. Our results point to polyatomic
crystals as promising hosts for coherent qubits in the solid state.


title:
Construction of Hamiltonian and Nambu forms for the shallow water
  equations

abstract:
  A systematic method to derive the Hamiltonian and Nambu form for the shallow
water equations, using the conservation for energy and potential enstrophy, is
presented. Different mechanisms, such as vortical flows and emission of gravity
waves, emerge from different conservation laws (CLs) for total energy and
potential enstrophy. The equations are constructed using exterior differential
forms and self-adjoint operators and result in the sum of two Nambu brackets,
one for the vortical flow and one for the wave-mean flow interaction, and a
Poisson bracket representing the interaction between divergence and geostrophic
imbalance. The advantage of this approach is that the Hamiltonian and Nambu
forms can be here written in a coordinate independent form.

categories: math-ph math.MP physics.ao-ph physics.flu-dyn


title: On the Einstein-Podolsky-Rosen paradox using discrete time physics

abstract:
  The Einstein-Podolski-Rosen paradox highlights several strange properties of
quantum mechanics including the super position of states, the non locality and
its limitation to determine an experiment only statistically. Here, this well
known paradox is revisited theoretically for a pair of spin 1/2 systems in a
singlet state under the assumption that in classical physics time evolves in
discrete time steps Deltat while in quantum mechanics the individual spin
system(s) evolve(s) between the eigenstates harmonically with a period of 4
Deltat. It is further assumed that time is a single variable, that the quantum
mechanics time evolution and the classical physics discrete time evolution are
coherent to each other, and that the precision of the start of the experiment
and of the measurement time point are much less than Deltat. Under these
conditions, it is demonstrated for a spin 1/2 system that the fast oscillation
between the eigen states spin up and spin down reproduces the expected outcome
of a single measurement as well as ensemble measurements without the need of
postulating a simultaneous superposition of the spin system in its quantum
state. When this concept is applied to a spin 1/2 system pair in a singlet
state it is shown that no entanglement between the two spins is necessary to
describe the system resolving the Einstein-Podolski-Rosen paradox.


title: Geometry Helps to Compare Persistence Diagrams

abstract:
  Exploiting geometric structure to improve the asymptotic complexity of
discrete assignment problems is a well-studied subject. In contrast, the
practical advantages of using geometry for such problems have not been
explored. We implement geometric variants of the Hopcroft--Karp algorithm for
bottleneck matching (based on previous work by Efrat el al.) and of the auction
algorithm by Bertsekas for Wasserstein distance computation. Both
implementations use k-d trees to replace a linear scan with a geometric
proximity query. Our interest in this problem stems from the desire to compute
distances between persistence diagrams, a problem that comes up frequently in
topological data analysis. We show that our geometric matching algorithms lead
to a substantial performance gain, both in running time and in memory
consumption, over their purely combinatorial counterparts. Moreover, our
implementation significantly outperforms the only other implementation
available for comparing persistence diagrams.


title:
Extended Gauss-Newton and ADMM-Gauss-Newton Algorithms for Low-Rank
  Matrix Optimization

abstract:
  In this paper, we develop a variant of the well-known Gauss-Newton (GN)
method to solve a class of nonconvex optimization problems involving low-rank
matrix variables. As opposed to the standard GN method, our algorithm allows
one to handle general smooth convex objective function. We show, under mild
conditions, that the proposed algorithm globally and locally converges to a
stationary point of the original problem. We also show empirically that the GN
algorithm achieves higher accurate solutions than the alternating minimization
algorithm (AMA). Then, we specify our GN scheme to handle the symmetric case
and prove its convergence, where AMA is not applicable. Next, we incorporate
our GN scheme into the alternating direction method of multipliers (ADMM) to
develop an ADMM-GN algorithm. We prove that, under mild conditions and a proper
choice of the penalty parameter, our ADMM-GN globally converges to a stationary
point of the original problem. Finally, we provide several numerical
experiments to illustrate the proposed algorithms. Our results show that the
new algorithms have encouraging performance compared to existing methods.


title:
Viscous corrections of the Time Incremental Minimization Scheme and
  Visco-Energetic Solutions to Rate-Independent Evolution Problems

abstract:
  We propose the new notion of Visco-Energetic solutions to rate-independent
systems $(X,\mathcal E,\mathsf d)$ driven by a time dependent energy $\mathcal
E$ and a dissipation quasi-distance $\mathsf d$ in a general metric-topological
space $X$. As for the classic Energetic approach, solutions can be obtained by
solving a modified time Incremental Minimization Scheme, where at each step the
dissipation (quasi-)distance $\mathsf d$ is incremented by a viscous correction
$\delta$ (e.g.~proportional to the square of the distance $\mathsf d$), which
penalizes far distance jumps by inducing a localized version of the stability
condition.
  We prove a general convergence result and a typical characterization by
Stability and Energy Balance in a setting comparable to the standard energetic
one, thus capable to cover a wide range of applications. The new refined Energy
Balance condition compensates the localized stability and provides a careful
description of the jump behavior: at every jump the solution follows an optimal
transition, which resembles in a suitable variational sense the discrete scheme
that has been implemented for the whole construction.


title: Unimodular measures on the space of all Riemannian manifolds

abstract:
  We study unimodular measures on the space $\mathcal M^d$ of all pointed
Riemannian $d$-manifolds. Examples can be constructed from finite volume
manifolds, from measured foliations with Riemannian leaves, and from invariant
random subgroups of Lie groups. Unimodularity is preserved under weak* limits,
and under certain geometric constraints (e.g. bounded geometry) unimodular
measures can be used to compactify sets of finite volume manifolds. One can
then understand the geometry of manifolds $M$ with large, finite volume by
passing to unimodular limits.
  We develop a structure theory for unimodular measures on $\mathcal M^d$,
characterizing them via invariance under a certain geodesic flow, and showing
that they correspond to transverse measures on a foliated `desingularization'
of $\mathcal M^d$. We also give a geometric proof of a compactness theorem for
unimodular measures on the space of pointed manifolds with pinched negative
curvature, and characterize unimodular measures supported on hyperbolic
$3$-manifolds with finitely generated fundamental group.


title: Nonlinear effects at the Fermilab Recycler e-cloud instability

abstract:
  Theoretical analysis of e-cloud instability in the Fermilab Recycler is
represented in the paper. The e-cloud in strong magnetic field is treated as a
set of immovable snakes each being initiated by some proton bunch. It is shown
that the instability arises because of injection errors of the bunches which
increase in time and from bunch to bunch along the batch being amplified by the
e-cloud electric field. The particular attention is given to nonlinear
additions to the cloud field. It is shown that the nonlinearity is the main
factor which restricts growth of the bunch amplitude. Possible role of the
field free parts of the Recycler id discussed as well. Results of calculations
are compared with experimental data demonstrating good correlation.


title: Higher-order expansions of extremes from mixed skew-t distribution

abstract:
  In this paper, we study the asymptotic behaviors of the extreme of mixed
skew-t distribution. We considered limits on distribution and density of
maximum of mixed skew-t distribution under linear and power normalization, and
further derived their higher-order expansions, respectively. Examples are given
to support our findings.


title: Multiplication operators on Orlicz and weighted Orlicz spaces

abstract:
  Let $(\Omega,\Sigma,\mu)$ be a $\sigma$-finite complete measure space,
$\tau:\Omega\rightarrow\Omega$ be a measurable transformation and $\phi$ be an
Orlicz function. In this article, first a necessary and sufficient condition
for the bounded multiplication operator $M_u$ on Orlicz space $L^\phi (\Omega)$
induced by measurable function $u$ to be completely continuous has been
established. Next by using Radon-Nikodym derivative $\omega = \frac{d \mu\circ
\tau^{-1}}{d \mu}$, the multiplication operator $M_u$ on weighted Orlicz space
$L^{\phi}_\omega(\Omega)$ have been characterized.


title: Crater formation during raindrop impact on sand

abstract:
  After a raindrop impacts on a granular bed, a crater is formed as both drop
and target deform. After an initial, transient, phase in which the maximum
crater depth is reached, the crater broadens outwards until a final steady
shape is attained. By varying the impact velocity of the drop and the packing
density of the bed, we find that avalanches of grains are important in the
second phase and hence, affect the final crater shape. In a previous paper, we
introduced an estimate of the impact energy going solely into sand deformation
and here we show that both the transient and final crater diameter collapse
with this quantity for various packing densities. The aspect ratio of the
transient crater is however altered by changes in the packing fraction.


title:
Acoustic Characterization of Environments (ACE) Challenge Results
  Technical Report

abstract:
  This document provides the results of the tests of acoustic parameter
estimation algorithms on the Acoustic Characterization of Environments (ACE)
Challenge Evaluation dataset which were subsequently submitted and written up
into papers for the Proceedings of the ACE Challenge. This document is
supporting material for a forthcoming journal paper on the ACE Challenge which
will provide further analysis of the results.


title: How Hard Is It to Control A Group?

abstract:
  We consider group identification models in which the aggregation of
individual opinions concerning who is qualified in a given society determines
the set of socially qualified persons. In this setting, we study the extent to
which social qualification can be changed when societies expand, shrink, or
partition themselves. The answers we provide are with respect to the
computational complexity of the corresponding control problems and fully cover
the class of consent aggregation rules introduced by Samet & Schmeidler (2003)
as well as procedural rules for group identification. We obtain both
polynomial-time solvability results and NP-hardness results. In addition, we
also study these problems from the parameterized complexity perspective, and
obtain some fixed-parameter tractability results.


title:
Pressure-driven 4$f$ localized-itinerant crossover in heavy fermion
  compound CeIn$_{3}$: A first-principles many-body perspective

abstract:
  The localized-itinerant nature of Ce-4$f$ valence electrons in heavy fermion
compound CeIn$_{3}$ under pressure is studied thoroughly by means of the
combination of density functional theory and single-site dynamical mean-field
theory. The detailed evolutions of electronic structures of CeIn$_{3}$,
including total and partial density of states, momentum-resolved spectral
functions, and valence state histograms etc., are calculated in a wide pressure
range where the corresponding volume compression $V/V_0 \in [0.6,1.0]$ (here
$V_0$ is the experimental crystal volume) at $T \cong 116$ K. Upon increasing
pressure, two strong peaks associated with the Ce-$4f$ states emerge near the
Fermi level, and the $c$-$f$ hybridization and valence state fluctuation are
enhanced remarkably. Moreover, the kinetic and potential energies raise, while
the occupancy, total angular momentum, and low-energy scattering rate of the
Ce-$4f$ electrons decline with respect to pressure. All the physical
observables considered here exhibit prominent kinks or fluctuations in $V/V_0
\in [0.80,0.90]$, which are probably the desired fingerprints for the Ce-4$f$
localized-itinerant crossover.


title: sec-cs: Getting the Most out of Untrusted Cloud Storage

abstract:
  We present sec-cs, a hash-table-like data structure for file contents on
untrusted storage that is both secure and storage-efficient. We achieve
authenticity and confidentiality with zero storage overhead using deterministic
authenticated encryption. State-of-the-art data deduplication approaches
prevent redundant storage of shared parts of different contents irrespective of
whether relationships between contents are known a priori or not.
  Instead of just adapting existing approaches, we introduce novel
(multi-level) chunking strategies, ML-SC and ML-CDC, which are significantly
more storage-efficient than existing approaches in presence of high redundancy.
  We prove sec-cs's security, publish a ready-to-use implementation, and
present results of an extensive analytical and empirical evaluation that show
its suitability for, e.g., future backup systems that should preserve many
versions of files on little available cloud storage.


title:
FOMTrace: Interactive Video Segmentation By Image Graphs and Fuzzy
  Object Models

abstract:
  Common users have changed from mere consumers to active producers of
multimedia data content. Video editing plays an important role in this
scenario, calling for simple segmentation tools that can handle fast-moving and
deformable video objects with possible occlusions, color similarities with the
background, among other challenges. We present an interactive video
segmentation method, named FOMTrace, which addresses the problem in an
effective and efficient way. From a user-provided object mask in a first frame,
the method performs semi-automatic video segmentation on a spatiotemporal
superpixel-graph, and then estimates a Fuzzy Object Model (FOM), which refines
segmentation of the second frame by constraining delineation on a pixel-graph
within a region where the object's boundary is expected to be. The user can
correct/accept the refined object mask in the second frame, which is then
similarly used to improve the spatiotemporal video segmentation of the
remaining frames. Both steps are repeated alternately, within interactive
response times, until the segmentation refinement of the final frame is
accepted by the user. Extensive experiments demonstrate FOMTrace's ability for
tracing objects in comparison with state-of-the-art approaches for interactive
video segmentation, supervised, and unsupervised object tracking.


title:
Collisions versus stellar winds in the runaway merger scenario: place
  your bets

abstract:
  The runaway merger scenario is one of the most promising mechanisms to
explain the formation of intermediate-mass black holes (IMBHs) in young dense
star clusters (SCs). On the other hand, the massive stars that participate in
the runaway merger lose mass by stellar winds. This effect is tremendously
important, especially at high metallicity. We discuss N-body simulations of
massive (~6x10^4 Msun) SCs, in which we added new recipes for stellar winds and
supernova explosion at different metallicity. At solar metallicity, the mass of
the final merger product spans from few solar masses up to ~30 Msun. At low
metallicity (0.01-0.1 Zsun) the maximum remnant mass is ~250 Msun, in the range
of IMBHs. A large fraction (~0.6) of the massive remnants are not ejected from
the parent SC and acquire stellar or black hole companions. Finally, I discuss
the importance of this result for gravitational wave detection.


title: Schur algorithm for Stieltjes indefinite moment problem

abstract:
  Nondegenerate truncated indefinite Stieltjes moment problem in the class
$\mathbf{N}_{\kappa}^{k}$ of generalized Stieltjes functions is considered. To
describe the set of solutions of this problem we apply the Schur step-by-step
algorythm, which leads to the expansion of these solutions in generalized
Stieltjes continuous fractions studied recently in \cite{DK15}. Explicit
formula for the resolvent matrix in terms of generalized Stieltjes polynomials
is found.


title: A note on Jones polynomial and cosmetic surgery

abstract:
  We show that two Dehn surgeries on a knot $K$ never yield manifolds that are
homeomorphic as oriented manifolds if $V_K''(1)\neq 0$ or $V_K'''(1)\neq 0$. As
an application, we verify the cosmetic surgery conjecture for all knots with no
more than $11$ crossings except for three $10$-crossing knots and five
$11$-crossing knots. We also compute the finite type invariant of order $3$ for
two-bridge knots and Whitehead doubles, from which we prove several
nonexistence results of purely cosmetic surgery.


title: Stochastic resin transfer molding process

abstract:
  We consider one-dimensional and two-dimensional models of the stochastic
resin transfer molding process, which are formulated as random moving boundary
problems. We study their properties, analytically in the one-dimensional case
and numerically in the two-dimensional case. We show how variability of time to
fill depends on correlation lengths and smoothness of a random permeability
field.


title:
Numerical modelling of the lobes of radio galaxies in cluster
  environments - III. Powerful relativistic and nonrelativistic jets

abstract:
  We present results from two suites of simulations of powerful radio galaxies
in poor cluster environments, with a focus on the formation and evolution of
the radio lobes. One suite of models uses relativistic hydrodynamics and the
other relativistic magnetohydrodynamics; both are set up to cover a range of
jet powers and velocities. The dynamics of the lobes are shown to be in good
agreement with analytical models and with previous numerical models, confirming
in the relativistic regime that the observed widths of radio lobes may be
explained if they are driven by very light jets. The ratio of energy stored in
the radio lobes to that put into the intracluster gas is seen to be the same
regardless of jet power, jet velocity or simulation type, suggesting that we
have a robust understanding of the work done on the ambient gas by this type of
radio source. For the most powerful jets we at times find magnetic field
amplification by up to a factor of two in energy, but mostly the magnetic
energy in the lobes is consistent with the magnetic energy injected. We confirm
our earlier result that for jets with a toroidally injected magnetic field, the
field in the lobes is predominantly aligned with the jet axis once the lobes
are well developed, and that this leads to radio flux anisotropies of up to a
factor of about two for mature sources. We reproduce the relationship between
151-MHz luminosity and jet power determined analytically in the literature.


title: Status of CMB observations in 2015

abstract:
  The 2.725 K cosmic microwave background has played a key role in the
development of modern cosmology by providing a solid observational foundation
for constraining possible theories of what happened at very large redshifts and
theoretical speculation reaching back almost to the would-be big bang initial
singularity. After recounting some of the lesser known history of this area, I
summarize the current observational situation and also discuss some exciting
challenges that lie ahead: the search for B modes, the precision mapping of the
CMB gravitational lensing potential, and the ultra-precise characterization of
the CMB frequency spectrum, which would allow the exploitation of spectral
distortions to probe new physics.


title: Clustering and Classification of Genetic Data Through U-Statistics

abstract:
  Genetic data are frequently categorical and have complex dependence
structures that are not always well understood. For this reason, clustering and
classification based on genetic data, while highly relevant, are challenging
statistical problems. Here we consider a highly versatile U-statistics based
approach built on dissimilarities between pairs of data points for
nonparametric clustering. In this work we propose statistical tests to assess
group homogeneity taking into account the multiple testing issues, and a
clustering algorithm based on dissimilarities within and between groups that
highly speeds up the homogeneity test. We also propose a test to verify
classification significance of a sample in one of two groups. A Monte Carlo
simulation study is presented to evaluate power of the classification test,
considering different group sizes and degree of separation. Size and power of
the homogeneity test are also analyzed through simulations that compare it to
competing methods. Finally, the methodology is applied to three different
genetic datasets: global human genetic diversity, breast tumor gene expression
and Dengue virus serotypes. These applications showcase this statistical
framework's ability to answer diverse biological questions while adapting to
the specificities of the different datatypes.


title:
Sur la variation quadratique totale de la suite des parties
  fractionnaires des quotients d'un nombre r\'eel positif par les nombres
  entiers naturels cons\'ecutifs

abstract:
  We give an asymptotic formula for the quadratic total variation of the
sequence of fractional parts of the quotients of a positive real number by the
consecutive natural numbers.


title:
Sur la variation totale de la suite des parties fractionnaires des
  quotients d'un nombre r{\'e}el positif par les nombres entiers naturels
  cons{\'e}cutifs

abstract:
  We give an asymptotic formula for the total variation of the sequence of
fractional parts of the quotients of a positive real number by the consecutive
natural numbers.


title:
A mixed finite element approximation for Darcy-Forchheimer flows of
  slightly compressible fluids

abstract:
  In this paper, we consider the generalized Forchheimer flows for slightly
compressible fluids in porous media. Using Muskat's and Ward's general form of
Forchheimer equations, we describe the flow of a single-phase fluid in $\mathbb
R^d, d\ge 2$ by a nonlinear degenerate system of density and momentum. A mixed
finite element method is proposed for the approximation of the solution of the
above system. The stability of the approximations are proved; the error
estimates are derived for the numerical approximations for both continuous and
discrete time procedures. The continuous dependence of numerical solutions on
physical parameters are demonstrated. Experimental studies are presented
regarding convergence rates and showing the dependence of the solution on the
physical parameters.


title: Low-Complexity MIMO Precoding for Finite-Alphabet Signals

abstract:
  This paper investigates the design of precoders for single-user
multiple-input multiple-output (MIMO) channels, and in particular for
finite-alphabet signals. Based on an asymptotic expression for the mutual
information of channels exhibiting line-of-sight components and rather general
antenna correlations, precoding structures that decompose the general channel
into a set of parallel subchannel pairs are proposed. Then, a low-complexity
iterative algorithm is devised to maximize the sum mutual information of all
pairs. The proposed algorithm significantly reduces the computational load of
existing approaches with only minimal loss in performance. The complexity
savings increase with the number of transmit antennas and with the cardinality
of the signal alphabet, making it possible to support values thereof that were
unmanageable with existing solutions. Most importantly, the proposed solution
does not require instantaneous channel state information (CSI) at the
transmitter, but only statistical CSI.


title:
Resolvent bounds for jump generators and ground state asymptotics for
  nonlocal Schr\"{o}dinger operators

abstract:
  The paper deals with jump generators with a convolution kernel. Assuming that
the kernel decays either exponentially or polynomially we prove a number of
lower and upper bounds for the resolvent of such operators. We consider two
applications of these results. First we obtain pointwise estimates for
principal eigenfunction of jump generators perturbed by a compactly supported
potential (so-called nonlocal Schr\"odinger operators). Then we consider the
Cauchy problem for the corresponding inhomogeneous evolution equations and
study the behaviour of its solutions.


title: Effects of Elliptically Polarizing Undulator on Beam Dynamics in PLS-II

abstract:
  The non-linear effects caused by the intrinsic field transverse roll-off in
an Elliptically Polarizing Undulator with 72-mm period and maximum peak field
of 0.72 T (EPU72) on the dynamics aperture of the Pohang Light Source II
(PLS-II) were investigated. A kick map and Frequency map analysis both
demonstrated that EPU72 will not reduce the lifetime or cause injection
problems in PLS-II.


title: Archimedes Force on Casimir Apparatus

abstract:
  We address a problem of Casimir apparatus in dense medium and weak
gravitational field. The falling of the apparatus has to be governed by the
equivalence principle, with proper account for contributions to the weight of
the apparatus from its material part and from distorted quantum fields. We
discuss general expression for the corresponding force in metric with
cylindrical symmetry. By way of example we compute explicit expression for
Archimedes force, acting on the Casimir apparatus of finite size, immersed into
thermal bath of free scalar field. It is shown that besides universal term,
proportional to the volume of the apparatus, there are non-universal quantum
corrections, depending on the boundary conditions.


title:
Viscous effects on the acoustics and stability of a shear layer over an
  impedance wall

abstract:
  The effect of viscosity and thermal conduction on the acoustics in a shear
layer above an impedance wall is investigated numerically and asymptotically by
solving the compressible linearised Navier-Stokes equations. It is found that
viscothermal effects can be as important as shear, and therefore including
shear while neglecting viscothermal effects by solving the linearised Euler
equations is questionable. In particular, the damping rate of upstream
propagating waves is found to be dramatically under-predicted by the LEE in
certain instances. The effects of viscosity on stability are also found to be
important. Short wavelength disturbances are stabilised by viscosity, greatly
altering the characteristic wavelength and maximum growth rate of instability.
For the parameters typical of aeroacoustic simulations considered here, the
Reynolds number below which the flow stabilizes ranges from $10^5$ to $10^7$.
By assuming a thin but nonzero-thickness boundary layer, asymptotic analysis
leads to a system of boundary layer governing equations for the acoustics. This
system may be solved numerically to produce an effective impedance boundary
condition, applicable at the wall of a uniform inviscid flow, that accounts for
both the shear and viscosity within the boundary layer. An alternative
asymptotic analysis in the high frequency limit yields a different set of
equations with analytic solutions. The acoustic mode shapes and axial
wavenumbers from both asymptotic analyses compare well with numerical solutions
of the full LNSE. A closed-form effective impedance boundary condition is
derived from the high-frequency asymptotics, suitable for application in
frequency-domain numerical simulations. Finally, surface waves are considered,
and it is shown that a viscous flow over an impedance lining supports a greater
number of surface wave modes than an inviscid flow.


title: Hamiltonian simulation of the Schwinger model at finite temperature

abstract:
  Using Matrix Product Operators (MPO) the Schwinger model is simulated in
thermal equilibrium. The variational manifold of gauge invariant MPO is
constructed to represent Gibbs states. As a first application the chiral
condensate in thermal equilibrium is computed and agreement with earlier
studies is found. Furthermore, as a new application the Schwinger model is
probed with a fractional charged static quark-antiquark pair separated
infinitely far from each other. A critical temperature beyond which the string
tension is exponentially suppressed is found, which is in qualitative agreement
with analytical studies in the strong coupling limit. Finally, the CT symmetry
breaking is investigated and our results strongly suggest that the symmetry is
restored at any nonzero temperature.


title: A Generalized Bass Model for Product Growth in Networks

abstract:
  Many products and innovations become well-known and widely adopted through
the social interactions of individuals in a population. The Bass diffusion
model has been widely used to model the temporal evolution of adoption in such
social systems. In the model, the likelihood of a new adoption is proportional
to the number of previous adopters, implicitly assuming a global (or
homogeneous) interaction among all individuals in the network. Such global
interactions do not exist in many large social networks, however. Instead,
individuals typically interact with a small part of the larger population. To
quantify the growth rate (or equivalently the adoption timing) in networks with
limited interactions, we study a stochastic adoption process where the
likelihood that each individual adopts is proportional to the number of
adopters among the small group of persons he/she interacts with (and not the
entire population of adopters). When the underlying network of interactions is
a random $k$-regular graph, we compute the sample path limit of the fraction of
adopters. We show the limit coincides with the solution of a differential
equation which can viewed as a generalization of the Bass diffusion model. When
the degree $k$ is bounded, we show the adoption curve differs significantly
from the one corresponds to the Bass diffusion model. In particular, the
adoption grows more slowly than what the Bass model projects. In addition, the
adoption curve is asymmetric, unlike that of the Bass diffusion model. Such
asymmetry has important consequences for the estimation of market potential.
Finally, we calculate the timing of early adoptions at finer scales, e.g.,
logarithmic in the population size.


title: Closed-loop approach to thermodynamics

abstract:
  We present the closed loop approach to linear nonequilibrium thermodynamics
considering a generic heat engine dissipatively connected to two temperature
baths. The system is usually quite generally characterized by two parameters:
the output power $P$ and the conversion efficiency $\eta$, to which we add a
third one, the working frequency $\omega$. We establish that a detailed
understanding of the effects of the dissipative coupling on the energy
conversion process, necessitates the knowledge of only two quantities: the
system's feedback factor $\beta$ and its open-loop gain $A_{0}$, the product of
which, $A_{0}\beta$, characterizes the interplay between the efficiency, the
output power and the operating rate of the system. By placing thermodynamics
analysis on a higher level of abstraction, the feedback loop approach provides
a versatile and economical, hence a very efficient, tool for the study of
\emph{any} conversion engine operation for which a feedback factor may be
defined.


title: Optimal Resource Extraction in Regime Switching L\'evy Markets

abstract:
  This paper studies the problem of optimally extracting nonrenewable natural
resource in light of various financial and economic restrictions and
constraints. Taking into account the fact that the market values of the main
natural resources i.e. oil, natural gas, copper,...,etc, fluctuate randomly
following global and seasonal macroeconomic parameters, these values are
modeled using Markov switching L\'evy processes. We formulate this problem as
finite-time horizon combined optimal stopping and optimal control problem. We
prove that the value function is the unique viscosity solution of the
corresponding Hamilton-Jacobi-Bellman equations. Moreover, we prove the
convergence of a finite difference approximation of the value function.
Numerical examples are presented to illustrate these results.


title:
On the search for the chiral anomaly in Weyl semimetals: The negative
  longitudinal magnetoresistance

abstract:
  Recently, the existence of massless chiral (Weyl) fermions has been
postulated in a class of semi-metals with a non-trivial energy dispersion.These
materials are now commonly dubbed Weyl semi-metals (WSM).One predicted property
of Weyl fermions is the chiral or Adler-Bell-Jackiw anomaly, a chirality
imbalance in the presence of parallel magnetic and electric fields. In WSM, it
is expected to induce a negative longitudinal magnetoresistance (NMR), the
chiral magnetic effect.Here, we present experimental evidence that the
observation of the chiral magnetic effect can be hindered by an effect called
"current jetting". This effect also leads to a strong apparent NMR, but it is
characterized by a highly non-uniform current distribution inside the sample.
It appears in materials possessing a large field-induced anisotropy of the
resistivity tensor, such as almost compensated high-mobility semimetals due to
the orbital effect.In case of a non-homogeneous current injection, the
potential distribution is strongly distorted in the sample.As a consequence, an
experimentally measured potential difference is not proportional to the
intrinsic resistance.Our results on the MR of the WSM candidate materials NbP,
NbAs, TaAs, TaP exhibit distinct signatures of an inhomogeneous current
distribution, such as a field-induced "zero resistance' and a strong dependence
of the `measured resistance" on the position, shape, and type of the voltage
and current contacts on the sample. A misalignment between the current and the
magnetic-field directions can even induce a "negative resistance".
Finite-element simulations of the potential distribution inside the sample,
using typical resistance anisotropies, are in good agreement with the
experimental findings. Our study demonstrates that great care must be taken
before interpreting measurements of a NMR as evidence for the chiral anomaly in
putative Weyl semimetals.


title:
Microscopic description for the emergence of collective dissipation in
  extended quantum systems

abstract:
  Practical implementations of quantum technology are limited by unavoidable
effects of decoherence and dissipation. With achieved experimental control for
individual atoms and photons, more complex platforms composed by several units
can be assembled enabling distinctive forms of dissipation and decoherence, in
independent heat baths or collectively into a common bath, with dramatic
consequences for the preservation of quantum coherence. The cross-over between
these two regimes has been widely attributed in the literature to the system
units being farther apart than the bath's correlation length. Starting from a
microscopic model of a structured environment (a crystal) sensed by two bosonic
probes, here we show the failure of such conceptual relation, and identify the
exact physical mechanism underlying this cross-over, displaying a sharp
contrast between dephasing and dissipative baths. Depending on the frequency of
the system and, crucially, on its orientation with respect to the crystal axes,
collective dissipation becomes possible for very large distances between
probes, opening new avenues to deal with decoherence in phononic baths.


title: Simple Question Answering by Attentive Convolutional Neural Network

abstract:
  This work focuses on answering single-relation factoid questions over
Freebase. Each question can acquire the answer from a single fact of form
(subject, predicate, object) in Freebase. This task, simple question answering
(SimpleQA), can be addressed via a two-step pipeline: entity linking and fact
selection. In fact selection, we match the subject entity in a fact candidate
with the entity mention in the question by a character-level convolutional
neural network (char-CNN), and match the predicate in that fact with the
question by a word-level CNN (word-CNN). This work makes two main
contributions. (i) A simple and effective entity linker over Freebase is
proposed. Our entity linker outperforms the state-of-the-art entity linker over
SimpleQA task. (ii) A novel attentive maxpooling is stacked over word-CNN, so
that the predicate representation can be matched with the predicate-focused
question representation more effectively. Experiments show that our system sets
new state-of-the-art in this task.


title: Molecular mechanism for cavitation in water under tension

abstract:
  Despite its relevance in biology and engineering, the molecular mechanism
driving cavitation in water remains unknown. Using computer simulations, we
investigate the structure and dynamics of vapor bubbles emerging from
metastable water at negative pressures. We find that in the early stages of
cavitation, bubbles are irregularly shaped and become more spherical as they
grow. Nevertheless, the free energy of bubble formation can be perfectly
reproduced in the framework of classical nucleation theory (CNT) if the
curvature dependence of the surface tension is taken into account. Comparison
of the observed bubble dynamics to the predictions of the macroscopic
Rayleigh--Plesset (RP) equation, augmented with thermal fluctuations,
demonstrates that the growth of nanoscale bubbles is governed by viscous
forces. Combining the dynamical prefactor determined from the RP equation with
the free energy of CNT yields an analytical expression for the cavitation rate
that reproduces the simulation results very well over a wide range of
pressures. Furthermore, our theoretical predictions are in excellent agreement
with cavitation rates obtained from inclusion experiments. This suggests that
homogeneous nucleation is observed in inclusions, whereas only heterogeneous
nucleation on impurities or defects occurs in other experiments.


title:
Non-perturbative landscape of the Mott-Hubbard transition: Multiple
  divergence lines around the critical endpoint

abstract:
  We analyze the highly non-perturbative regime surrounding the Mott-Hubbard
metal-to-insulator transition (MIT) by means of dynamical mean field theory
calculations at the two-particle level. By extending the results of Sch\"afer,
et al. [Phys. Rev. Lett. 110, 246405 (2013)] we show the existence of
infinitely many lines in the phase diagram of the Hubbard model where the local
Bethe-Salpeter equations, and the related irreducible vertex functions, become
singular in the charge as well as the particle-particle channel. These
divergence lines accumulate around the critical Mott endpoint in accordance
with the interpretation as precursors of the MIT. By comparing our numerical
data with analytical calculations of increasing complexity, such as for the
disordered Binary Mixture and Falicov-Kimball (FK) models, as well as for the
atomic limit (AL) case, (i) we identify two different kinds of divergences
lines; (ii) we classify them in terms of the frequency-structure of the
associated singular eigenvectors; (iii) we investigate their relation to the
multiple branches in the Luttinger-Ward formalism. Moreover, we could
distinguish the situations where the multiple divergences simply reflect the
emergence of an underlying, unique energy scale $\nu^*$ below which
perturbation theory does no longer apply, from those where the breakdown of
perturbation theory affects, not trivially, different energy regimes. Finally,
we discuss the implications of our results on the theoretical understanding of
the non-perturbative physics around the MIT and for future developments of
many-body algorithms applicable in this regime.


title: New singular Gelfand-Tsetlin $\mathfrak{gl} (n)$-modules of index 2

abstract:
  Singular Gelfand-Tsetlin modules of index 2 are modules whose tableaux bases
may have singular pairs but no singular triples of entries on each row. In this
paper we construct singular Gelfand-Tsetlin modules for arbitrary singular
character of index 2. Explicit bases of derivative tableaux and the action of
the generators of $\mathfrak{gl}(n)$ are given for these modules. Our
construction leads to new families of irreducible Gelfand-Tsetlin modules and
also provides tableaux bases for some simple Verma modules.


title:
A Fractional Diffusion Equation for an n-Dimensional Correlated Levy
  Walk

abstract:
  Levy walks define a fundamental concept in random walk theory which allows
one to model diffusive spreading that is faster than Brownian motion. They have
many applications across different disciplines. However, so far the derivation
of a diffusion equation for an n-dimensional correlated Levy walk remained
elusive. Starting from a fractional Klein-Kramers equation here we use a moment
method combined with a Cattaneo approximation to derive a fractional diffusion
equation for superdiffusive short range auto-correlated Levy walks in the large
time limit, and solve it. Our derivation discloses different dynamical
mechanisms leading to correlated Levy walk diffusion in terms of quantities
that can be measured experimentally.


title:
Spatial entanglement entropy in the ground state of the Lieb-Liniger
  model

abstract:
  We consider the entanglement between two spatial subregions in the
Lieb-Liniger model of bosons in one spatial dimension interacting via a contact
interaction. Using ground state path integral quantum Monte Carlo we
numerically compute the R\'{e}nyi entropy of the reduced density matrix of the
subsystem as a measure of entanglement. Our numerical algorithm is based on a
replica method previously introduced by the authors, which we extend to
efficiently study the entanglement of spatial subsystems of itinerant bosons.
We confirm a logarithmic scaling of the R\'{e}nyi entropy with subsystem size
that is expected from conformal field theory, and compute the non-universal
subleading constant for interaction strengths ranging over two orders of
magnitude. In the strongly interacting limit, we find agreement with the known
free fermion result.


title: Combinatorial analysis of the period mapping: topology of 2D fibers

abstract:
  We study the periods mapping from the moduli space of real hyperelliptic
curves with marked point on an oriented oval to the euclidean space. The
mapping arises in the analysis of Chebyshev construction used in the
constrained optimization of the uniform norm of polynomials and rational
functions. The decomposition of the moduli space into polyhedra labeled by
planar graphs allows to investigate the global topology of low dimensional
fibers of the periods mapping.


title:
Bootstrapping Distantly Supervised IE using Joint Learning and Small
  Well-structured Corpora

abstract:
  We propose a framework to improve performance of distantly-supervised
relation extraction, by jointly learning to solve two related tasks:
concept-instance extraction and relation extraction. We combine this with a
novel use of document structure: in some small, well-structured corpora,
sections can be identified that correspond to relation arguments, and
distantly-labeled examples from such sections tend to have good precision.
Using these as seeds we extract additional relation examples by applying label
propagation on a graph composed of noisy examples extracted from a large
unstructured testing corpus. Combined with the soft constraint that concept
examples should have the same type as the second argument of the relation, we
get significant improvements over several state-of-the-art approaches to
distantly-supervised relation extraction.


title: Improving photometric redshifts with Ly$\alpha$ tomography

abstract:
  Forming a three dimensional view of the Universe is a long-standing goal of
astronomical observations, and one that becomes increasingly difficult at high
redshift. In this paper we discuss how tomography of the intergalactic medium
(IGM) at $z\simeq 2.5$ can be used to estimate the redshifts of massive
galaxies in a large volume of the Universe based on spectra of galaxies in
their background. Our method is based on the fact that hierarchical structure
formation leads to a strong dependence of the halo density on large-scale
environment. A map of the latter can thus be used to refine our knowledge of
the redshifts of halos and the galaxies and AGN which they host. We show that
tomographic maps of the IGM at a resolution of $2.5\,h^{-1}$Mpc can determine
the redshifts of more than 90 per cent of massive galaxies with redshift
uncertainty $\Delta z/(1+z)=0.01$. Higher resolution maps allow such redshift
estimation for lower mass galaxies and halos.


title:
Gapless helical superconductivity on the surface of a three-dimensional
  topological insulator

abstract:
  Recent angle-resolved photoemission experiments have observed a
proximity-induced superconducting gap in the helical surface states of a thin
film of the 3D topological insulator Bi$_2$Se$_3$ grown on a superconducting
NbSe$_2$ substrate. The superconducting coherence peaks in the electronic
density of states are strongly suppressed when the topological insulator is
doped with magnetic Mn impurities, which was interpreted as the complete
destruction of helical superconductivity in the topological surface states.
Motivated by these experiments, we explore a different possibility: gapless
helical superconductivity, where a gapless electronic density of states
coexists with a nonzero helical superconducting order parameter. We study a
model of superconducting Dirac fermions coupled to random magnetic impurities
within the Abrikosov-Gor'kov framework, and find finite regions of gapless
helical superconductivity in the phase diagram of the system for both
proximity-induced and intrinsic superconductivity. For the latter, we derive
universal rates of supression of the superconducting transition temperature due
to magnetic scattering and, for a Fermi level at the Dirac point, a universal
rate of increase of the quantum critical attraction strength.


title: Memory-Efficient Backpropagation Through Time

abstract:
  We propose a novel approach to reduce memory consumption of the
backpropagation through time (BPTT) algorithm when training recurrent neural
networks (RNNs). Our approach uses dynamic programming to balance a trade-off
between caching of intermediate results and recomputation. The algorithm is
capable of tightly fitting within almost any user-set memory budget while
finding an optimal execution policy minimizing the computational cost.
Computational devices have limited memory capacity and maximizing a
computational performance given a fixed memory budget is a practical use-case.
We provide asymptotic computational upper bounds for various regimes. The
algorithm is particularly effective for long sequences. For sequences of length
1000, our algorithm saves 95\% of memory usage while using only one third more
time per iteration than the standard BPTT.


title: Length bias in Encoder Decoder Models and a Case for Global Conditioning

abstract:
  Encoder-decoder networks are popular for modeling sequences probabilistically
in many applications. These models use the power of the Long Short-Term Memory
(LSTM) architecture to capture the full dependence among variables, unlike
earlier models like CRFs that typically assumed conditional independence among
non-adjacent variables. However in practice encoder-decoder models exhibit a
bias towards short sequences that surprisingly gets worse with increasing beam
size.
  In this paper we show that such phenomenon is due to a discrepancy between
the full sequence margin and the per-element margin enforced by the locally
conditioned training objective of a encoder-decoder model. The discrepancy more
adversely impacts long sequences, explaining the bias towards predicting short
sequences.
  For the case where the predicted sequences come from a closed set, we show
that a globally conditioned model alleviates the above problems of
encoder-decoder models. From a practical point of view, our proposed model also
eliminates the need for a beam-search during inference, which reduces to an
efficient dot-product based search in a vector-space.


title:
Nanoscale confinement of ultrafast spin transfer torque exciting
  non-uniform spin dynamics by femtosecond spin current pulses

abstract:
  Spintronics had a widespread impact over the past decades due to transferring
information by spin rather than electric currents. Its further development
requires miniaturization and reduction of characteristic timescales of spin
dynamics combining the sub-nanometer spatial and femtosecond temporal ranges.
These demands shift the focus of interest towards the fundamental open question
of the interaction of femtosecond spin current (SC) pulses with a ferromagnet
(FM). The spatio-temporal properties of the impulsive spin transfer torque
exerted by ultrashort SC pulses on the FM open the time domain for probing
non-uniform magnetization dynamics. Here we employ laser-generated ultrashort
SC pulses for driving ultrafast spin dynamics in FM and analyzing its transient
local source. Transverse spins injected into FM excite inhomogeneous
high-frequency spin dynamics up to 0.6 THz, indicating that the perturbation of
the FM magnetization is confined to 2 nm.


title:
On the homogenization of a new class of locally periodic microstructures
  in linear elasticity with residual stress

abstract:
  Many biological and engineering materials have nonperiodic microstructures
for which classical periodic homogenization results do not apply. Certain
nonperiodic microstructures may be approximated by locally periodic
microstructures for which homogenization techniques are available. Motivated by
the consideration that such materials are often anisotropic and can posses
residual stresses, a broad class of locally periodic microstructures is
considered and the resulting effective macroscopic equations are derived. The
effective residual stress and effective elasticity tensor are determined by
solving unit cell problems at each point in the domain. However, it is found
that for a certain class of locally periodic microstructures, solving the unit
cell problems at only one point in the domain completely determines the
effective elasticity tensor.


title: Physics Fun with Discrete Scale Invariance

abstract:
  I construct a quantum field theory model with discrete scale invariance at
tree level. The model has some unusual mathematical properties (such as the
appearance of $q$-hypergeometric series) and may possibly have some interesting
physical properties as well. In this note, I explore some possible physics that
could be regarded as a violation of standard effective field theory ideas.


title:
Comparison of solar radio and EUV synoptic limb charts during the
  present solar maximum

abstract:
  The present solar cycle is particular in many aspects: it had a delayed
rising phase, it is the weakest of the last 100 years, and it presents two
peaks separated by more than one year. To understand the impact of these
characteristics on the solar chromosphere and coronal dynamics, images from a
wide wavelength range are needed. In this work we use the 17~GHz radio
continuum, formed in the upper chromosphere and the EUV lines 304 and
171~{\AA}, that come from the transition region (He II) and the corona (Fe IX,
X), respectively. We analyze daily images at 304 and 171~{\AA} obtained by the
Atmospheric Imaging Assembly (AIA). The 17~GHz maps were obtained by the
Nobeyama Radioheliograph (NoRH). To construct synoptic limb charts, we
calculated the mean emission of delimited limb areas with 100" wide and angular
separation of $5^\circ$. At the equatorial region, the results show an
hemispheric asymmetry of the solar activity. The northern hemisphere dominance
is coincident with the first sunspot number peak, whereas the second peak
occurs concurrently with the increase in the activity at the south. The polar
emission reflects the presence of coronal holes at both EUV wavelengths,
moreover, the 17~GHz polar brightenings can be associated with the coronal
holes. Until 2013, both EUV coronal holes and radio polar brightenings were
more predominant at the south pole. Since then they have not been apparent in
the north, but thus appear in the beginning of 2015 in the south as observed in
the synoptic charts. This work strengthens the association between coronal
holes and the 17~GHz polar brightenings as it is evident in the synoptic limb
charts, in agreement with previous case study papers. The enhancement of the
radio brightness in coronal holes is explained by the presence of bright
patches closely associated with the presence of intense unipolar magnetic
fields.


title: Weighing the Giants V: Galaxy Cluster Scaling Relations

abstract:
  We present constraints on the scaling relations of galaxy cluster X-ray
luminosity, temperature and gas mass (and derived quantities) with mass and
redshift, employing masses from robust weak gravitational lensing measurements.
These are the first such results obtained from an analysis that simultaneously
accounts for selection effects and the underlying mass function, and directly
incorporates lensing data to constrain total masses. Our constraints on the
scaling relations and their intrinsic scatters are in good agreement with
previous studies, and reinforce a picture in which departures from self-similar
scaling laws are primarily limited to cluster cores. However, the data are
beginning to reveal new features that have implications for cluster
astrophysics and provide new tests for hydrodynamical simulations. We find a
positive correlation in the intrinsic scatters of luminosity and temperature at
fixed mass, which is related to the dynamical state of the clusters. While the
evolution of the nominal scaling relations over the redshift range $0.0<z<0.5$
is consistent with self similarity, we find tentative evidence that the
luminosity and temperature scatters respectively decrease and increase with
redshift. Physically, this likely related to the development of cool cores and
the rate of major mergers. We also examine the scaling relations of redMaPPer
richness and Compton $Y$ from Planck. While the richness--mass relation is in
excellent agreement with recent work, the measured $Y$--mass relation departs
strongly from that assumed in the Planck cluster cosmology analysis. The latter
result is consistent with earlier comparisons of lensing and Planck
scaling-relation-derived masses.


title: Additive invariants for knots, links and graphs in 3-manifolds

abstract:
  We define two new families of invariants for (3-manifold, graph) pairs which
detect the unknot and are additive under connected sum of pairs and
(-1/2)-additive under trivalent vertex sum of pairs. The first of these
families is closely related to both bridge number and tunnel number. The second
of these families is a variation and generalization of Gabai's width for knots
in the 3-sphere. We give applications to the tunnel number and higher genus
bridge number of connected sums of knots.


title:
ZnSnS3 : Structure Prediction, Ferroelectricity, and Solar Cell
  Applications

abstract:
  The rapid growth of the solar energy industry has produced a strong demand
for high performance, efficient photoelectric materials. Many ferroelectrics,
composed of earth-abundant elements, are useful for solar cell applications due
to their large internal polarization. However, their wide band gaps prevent
them from absorbing light in the visible to mid-infrared range. Here, we
address the band gap issue by investigating, in particular, the substitution of
sulphur for oxygen in the perovskite structure ZnSnO3 . Using evolutionary
methods we identify the stable and metastable structures of ZnSnS3 and compare
them to those previously characterized for ZnSnO3 . Our results suggest that
ZnSnS3 forms a monoclinic structure followed by metastable ilmenite and
lithium-niobate structures. The latter structure is highly polarized and it
possesses a significantly reduced band gap of 1.28 eV. These desirable
characteristics make it a prime candidate for solar cell applications.


title:
Complexity of sparse polynomial solving: homotopy on toric varieties and
  the condition metric

abstract:
  This paper investigates the cost of solving systems of sparse polynomial
equations by homotopy continuation. First, a space of systems of $n$-variate
polynomial equations is specified through $n$ monomial bases. The natural locus
for the roots of those systems is known to be a certain toric variety. This
variety is a compactification of $(\mathbb C\setminus\{0\})^n$, dependent on
the monomial bases. A toric Newton operator is defined on that toric variety.
Smale's alpha theory is generalized to provide criteria of quadratic
convergence. Two condition numbers are defined and a higher derivative estimate
is obtained in this setting. The Newton operator and related condition numbers
turn out to be invariant through a group action related to the momentum map. A
homotopy algorithm is given, and is proved to terminate after a number of
Newton steps which is linear on the condition length of the lifted homotopy
path. This generalizes a result from Shub (2009).


title: Raising the SUSY-breaking scale in a Goldstone-Higgs model

abstract:
  We show that by combining the elementary-Goldstone-Higgs scenario and
supersymmetry it is possible to raise the scale of supersymmetry breaking to
several TeVs by relating it to the spontaneous-symmetry-breaking one. This is
achieved by first enhancing the global symmetries of the super-Higgs sector to
SU(4) and then embedding the electroweak sector and the Standard-Model
fermions. We determine the conditions under which the model achieves a vacuum
such that the resulting Higgs is a pseudo-Goldstone boson. The main results
are: the supersymmetry-breaking scale is identified with the
spontaneous-symmetry-breaking scale of SU(4) which is several TeVs above the
radiatively induced electroweak scale; intriguingly the global symmetry of the
Higgs sector predicts the existence of two super-Higgs multiplets with one mass
eigenstate playing the role of the pseudo-Goldstone Higgs; the
symmetry-breaking dynamics fixes $\tan \beta = 1$ and requires a supplementary
singlet chiral superfield. We finally discuss the spectrum of the model that
now features superpartners of the Standard-Model fermions and gauge bosons in
the multi-TeV range.


title: Numerical Evaluation of Accelerated-Assisted Entanglement Harvesting

abstract:
  We consider acceleration-assisted entanglement harvesting as evidenced in
correlations between two accelerating Unruh detectors coupled to a scalar
field. We elaborate on earlier studies, which in a stationary phase
approximation calculated the entanglement dependence on two parameters $c_1 =
\kappa L$, and $c_2 = \kappa \Omega \sigma^2$, where $\kappa$ describes the
detector's acceleration, $L$ their separation and $\Omega$ the energy splitting
in a pair of two state Unruh detectors. Here, we go beyond the stationary phase
approximation by performing a numerical calculation of entanglement harvesting,
allowing us to present the dependence on $c_3 = \sigma \Omega$, where $\sigma$
denotes the half width of a Gaussian window function specifying the
field-detector interaction, and show agreement with earlier work the large
$c_3$ limit.


title: Toward the analogue of thermally generated electromagnetic fields

abstract:
  Magnetic and vorticity fields evolution equations are known to obey the same
equation when effects of dissipation and sources terms are negligible. We
investigate the analogy between the two fields for non-vanishing dissipation
and sources. In addition to the Reynolds (Re)and Prandtl (Pr_M) numbers, we
define a new number (S_M) that is given by the ratio of the diffusive term to
the Biermann battery term and which allows for a different classification of
magnetised fluid behaviour. Numerical simulations of the two fields are then
carried out given a parameter space made of Reynolds, Prandtl and Source
numbers. We find it appropriate to present and discuss the findings against
Prandtl numbers given that these provide the link between viscous and magnetic
diffusion. Our simulations indicate that there exists a range of Prandtl
numbers for which the fields remain analogues which raises the important
question of how far the analogy goes.


title: Homology groups for particles on one-connected graphs

abstract:
  We present a mathematical framework for describing the topology of
configuration spaces for particles on one-connected graphs. In particular, we
compute the homology groups over integers for different classes of
one-connected graphs. Our approach is based on some fundamental combinatorial
properties of the configuration spaces, Mayer-Vietoris sequences for different
parts of configuration spaces and some limited use of discrete Morse theory. As
one of the results, we derive a closed-form formulae for ranks of the homology
groups for indistinguishable particles on tree graphs. We also give a detailed
discussion of the second homology group of the configuration space of both
distinguishable and indistinguishable particles. Our motivation is the search
for new kinds of quantum statistics.


title:
$\boldsymbol{SU(3)_{C}\otimes SU(3)_{L}\otimes U(1)_{X}}$ models in view
  of the $750$ GeV diphoton signal

abstract:
  We analyze the recent diphoton signal reported by ATLAS and CMS
collaborations in the context of the $SU(3)_{C}\otimes SU(3)_{L}\otimes
U(1)_{X}$ anomaly free models, with a 750 GeV scalar candidate which can decay
into two photons. These models may explain the 750GeV signal by means of one
loop decays to $\gamma\gamma$ through charged vector and Higgs bosons, as well
as top-, bottom- and electron-like exotic particles that arise naturally from
the condition of anomaly cancellations of the $SU(3)_{C}\otimes
SU(3)_{L}\otimes U(1)_{X}$ models.


title:
Chebyshev polynomial filtered subspace iteration in the Discontinuous
  Galerkin method for large-scale electronic structure calculations

abstract:
  The Discontinuous Galerkin (DG) electronic structure method employs an
adaptive local basis (ALB) set to solve the Kohn-Sham equations of density
functional theory (DFT) in a discontinuous Galerkin framework. The adaptive
local basis is generated on-the-fly to capture the local material physics, and
can systematically attain chemical accuracy with only a few tens of degrees of
freedom per atom. A central issue for large-scale calculations, however, is the
computation of the electron density (and subsequently, ground state properties)
from the discretized Hamiltonian in an efficient and scalable manner. We show
in this work how Chebyshev polynomial filtered subspace iteration (CheFSI) can
be used to address this issue and push the envelope in large-scale materials
simulations in a discontinuous Galerkin framework. We describe how the subspace
filtering steps can be performed in an efficient and scalable manner using a
two-dimensional parallelization scheme, thanks to the orthogonality of the DG
basis set and block-sparse structure of the DG Hamiltonian matrix. The
on-the-fly nature of the ALBs requires additional care in carrying out the
subspace iterations. We demonstrate the parallel scalability of the DG-CheFSI
approach in calculations of large-scale two-dimensional graphene sheets and
bulk three-dimensional lithium-ion electrolyte systems. Employing 55,296
computational cores, the time per self-consistent field iteration for a sample
of the bulk 3D electrolyte containing 8,586 atoms is 90 seconds, and the time
for a graphene sheet containing 11,520 atoms is 75 seconds.


title: TeamPhone: Networking Smartphones for Disaster Recovery

abstract:
  In this paper, we investigate how to network smartphones for providing
communications in disaster recovery. By bridging the gaps among different kinds
of wireless networks, we have designed and implemented a system called
TeamPhone, which provides smartphones the capabilities of communications in
disaster recovery. Specifically, TeamPhone consists of two components: a
messaging system and a self-rescue system. The messaging system integrates
cellular networking, ad-hoc networking and opportunistic networking seamlessly,
and enables communications among rescue workers. The self-rescue system groups,
schedules and positions the smartphones of trapped survivors. Such a group of
smartphones can cooperatively wake up and send out emergency messages in an
energy-efficient manner with their location and position information so as to
assist rescue operations. We have implemented TeamPhone as a prototype
application on the Android platform and deployed it on off-the-shelf
smartphones. Experimental results demonstrate that TeamPhone can properly
fulfill communication requirements and greatly facilitate rescue operations in
disaster recovery.


title:
Asynchronous Distributed Hypothesis Testing in the Presence of Crash
  Failures

abstract:
  This paper addresses the problem of distributed hypothesis testing in
multi-agent networks, where agents repeatedly collect local observations about
an unknown state of the world, and try to collaboratively detect the true state
through information exchange. We focus on the impact of failures and asynchrony
(two fundamental factors in distributed systems) on the performance of
consensus-based non-Bayesian learning. In particular, we consider the scenario
where the networked agents may suffer crash faults, and messages delay can be
arbitrarily long but finite. We identify the minimal global detectability of
the network for non-Bayesian rule to succeed. In addition, we obtain a
generalization of a celebrated result by Wolfowitz and Hajnal to submatrices,
which might be of independent interest.


title: Testing Gravity with Pulsar Scintillation Measurements

abstract:
  We propose to use pulsar scintillation measurements to test predictions of
alternative theories of gravity. Comparing to single-path pulsar timing
measurements, the scintillation measurements can achieve a factor of 10^5
improvement in timing accuracy, due to the effect of multi-path interference.
Previous scintillation measurements of PSR B0834+06 have data acquisition for
hours, making this approach sensitive to mHz gravitational waves. Therefore it
has unique advantages in measuring gravitational effect or other mechanisms (at
mHz and above frequencies) on light propagation. We illustrate its application
in constraining scalar gravitational-wave background, in which case the
sensitivities can be greatly improved with respect to previous limits. We
expect much broader applications in testing gravity with existing and future
pulsar scintillation observations.


title: Probing deformed quantum commutators

abstract:
  Quantum gravity theories predict a minimal length at the order of magnitude
of the Planck length, under which the concepts of space and time lose every
physical meaning. In quantum mechanics, the insurgence of such minimal length
can be described by introducing a modified position-momentum commutator, which
in turn yields a generalized uncertainty principle, where the uncertainty on
the position measurement has a lower bound. The value of the minimal length is
not predicted by theories and must be evaluated experimentally. In this paper,
we address the quantum bound to estimability of the minimal uncertainty length
by performing measurements on a harmonic oscillator, which is analytically
solvable in the deformed algebra of the Hilbert subspace.


title: Analytical study of coherence in seeded modulation instability

abstract:
  We derive analytical expressions for the coherence in the onset of modulation
instability, in excellent agreement with thorough numerical simulations. As
usual, we start by a linear perturbation analysis, where broadband noise is
added to a continuous wave (CW) pump; then, we investigate the effect of adding
a deterministic seed to the CW pump, a case of singular interest as it is
commonly encountered in parametric amplification schemes. Results for the
dependence of coherence on parameters such as fiber type, pump power,
propagated distance, seed signal-to-noise ratio are presented. Finally, we show
the importance of including higher-order linear and nonlinear dispersion when
dealing with generation in longer wavelength regions (mid IR). We believe these
results to be of relevance when applied to the analysis of the coherence
properties of supercontinua generated from CW pumps.


title:
The impact of surface area, volume, curvature and Lennard-Jones
  potential to solvation modeling

abstract:
  This paper explores the impact of surface area, volume, curvature and
Lennard-Jones potential on solvation free energy predictions. Rigidity surfaces
are utilized to generate robust analytical expressions for maximum, minimum,
mean and Gaussian curvatures of solvent-solute interfaces, and define a
generalized Poisson-Boltzmann (GPB) equation with a smooth dielectric profile.
Extensive correlation analysis is performed to examine the linear dependence of
surface area, surface enclosed volume, maximum curvature, minimum curvature,
mean curvature and Gaussian curvature for solvation modeling. It is found that
surface area and surfaces enclosed volumes are highly correlated to each
others, and poorly correlated to various curvatures for six test sets of
molecules. Different curvatures are weakly correlated to each other for six
test sets of molecules, but are strongly correlated to each other within each
test set of molecules. Based on correlation analysis, we construct twenty six
nontrivial nonpolar solvation models. Our numerical results reveal that the
Lennard-Jones (LJ) potential plays a vital role in nonpolar solvation modeling,
especially for molecules involving strong van der Waals interactions. It is
found that curvatures are at least as important as surface area or surface
enclosed volume in nonpolar solvation modeling. In conjugation with the GPB
model, various curvature based nonpolar solvation models are shown to offer
some of the best solvation free energy predictions for a wide range of test
sets. For example, root mean square errors from a model constituting surface
area, volume, mean curvature and LJ potential are less than 0.42 kcal/mol for
all test sets.


title:
Spin-1 Quasi-normal Frequencies in Schwarzschild space-time for Large
  Overtone Number

abstract:
  We analytically investigate the spin-1 quasinormal mode frequencies of
Schwarzschild black hole space-time. We formally determine these frequencies to
arbitrary order as an expansion for large imaginary part (i.e., large-n, where
n is the overtone number). As an example of the practicality of this formal
procedure, we explicitly calculate the asymptotic behaviour of the frequencies
up to order $n^{-5/2}$.


title: Critical Phenomena in Active Matter

abstract:
  We investigate the effect of self-propulsion on a mean-field order-disorder
transition. Starting from a $\varphi^4$ scalar field theory subject to an
exponentially correlated noise, we exploit the Unified Colored Noise
Approximation to map the non-equilibrium active dynamics onto an effective
equilibrium one. This allows us to follow the evolution of the second-order
critical point as a function of the noise parameters: the correlation time
$\tau$ and the noise strength $D$. Our results suggest that $\tau$ is a crucial
ingredient that changes the location of the critical point but, remarkably, not
the universality class of the model. We also estimate the effect of Gaussian
fluctuations on the mean-field approximation finding an Ornstein-Zernike like
expression for the static structure factor at long wave lengths. Finally, to
assess the validity of our predictions, we compare the mean-field theoretical
results with numerical simulations of active Lennard-Jones particles in two and
three dimensions, finding a good qualitative agreement at small $\tau$ values.


title:
Modifed Becke-Johnson exchange potential: improved modelling of lead
  halides for solar cell applications

abstract:
  We report first-principles calculations, within density functional theory, on
the lead halide compounds PbCl2, PbBr2, and CH3NH3PbBr3-xClx, taking into
account spin-orbit coupling. We show that, when the modified Becke-Johnson
exchange potential is used with a suitable choice of defining parameters,
excellent agreement between calculations and experiment is obtained. The
computational model is then used to study the effect of replacing the
methylammonium cation in CH3NH3PbI3 and CH3NH3PbBr3 with either N2H+5 or N2H+3,
which have slightly smaller ionic radii than methylammonium. We predict that a
considerable downshift in the values of the band gaps occurs with this
replacement. The resulting compounds would extend optical absorption down to
the near-infrared region, creating excellent light harvesters for solar cells.


title: Short term fluctuations of wind and solar power systems

abstract:
  Wind and solar power are known to be highly influenced by weather events and
may ramp up or down abruptly. Such events in the power production influence not
only the availability of energy, but also the stability of the entire power
grid. By analysing significant amounts of data from several regions around the
world with resolutions of seconds to minutes, we provide strong evidence that
renewable wind and solar sources exhibit multiple types of variability and
nonlinearity in the time scale of {\it seconds} and characterise their
stochastic properties. In contrast to previous findings, we show that only the
jumpy characteristic of renewable sources decreases when increasing the spatial
size over which the renewable energies are harvested. Otherwise, the strong
non-Gaussian, intermittent behaviour in the cumulative power of the total field
survives even for a country-wide distribution of the systems. The strong
fluctuating behaviour of renewable wind and solar sources can be well
characterised by Kolmogorov-like power spectra and $q-$exponential probability
density functions. Using the estimated potential shape of power time series, we
quantify the jumpy or diffusive dynamic of the power. Finally we propose a time
delayed feedback technique as a control algorithm to suppress the observed
short term non-Gaussian statistics in spatially strong correlated and
intermittent renewable sources.


title: Better partitions of protein graphs for subsystem quantum chemistry

abstract:
  Determining the interaction strength between proteins and small molecules is
key to analyzing their biological function. Quantum-mechanical calculations
such as \emph{Density Functional Theory} (DFT) give accurate and theoretically
well-founded results. With common implementations the running time of DFT
calculations increases quadratically with molecule size. Thus, numerous
subsystem-based approaches have been developed to accelerate quantum-chemical
calculations. These approaches partition the protein into different fragments,
which are treated separately. Interactions between different fragments are
approximated and introduce inaccuracies in the calculated interaction energies.
  To minimize these inaccuracies, we represent the amino acids and their
interactions as a weighted graph in order to apply graph partitioning. None of
the existing graph partitioning work can be directly used, though, due to the
unique constraints in partitioning such protein graphs. We therefore present
and evaluate several algorithms, partially building upon established concepts,
but adapted to handle the new constraints. For the special case of partitioning
a protein along the main chain, we also present an efficient dynamic
programming algorithm that yields provably optimal results. In the general
scenario our algorithms usually improve the previous approach significantly and
take at most a few seconds.