title:
Robust Max-Min Fairness Energy Harvesting in Secure MISO Cognitive Radio
  With SWIPT

abstract:
  A multiple-input single-output cognitive radio downlink network is studied
with simultaneous wireless information and power transfer. In this network, a
secondary user coexists with multiple primary users and multiple energy
harvesting receivers. In order to guarantee secure communication and energy
harvesting, the problem of robust secure artificial noise-aided beamforming and
power splitting design is investigated under imperfect channel state
information. Specifically, the max-min fairness energy harvesting problem is
formulated under the bounded channel state information error model. A
one-dimensional search algorithm based on ${\cal S}\text{-Procedure} $ is
proposed to solve the problem. It is shown that the optimal robust secure
beamforming can be achieved. A tradeoff is elucidated between the secrecy rate
of the secondary user receiver and the energy harvested by the energy
harvesting receivers under a max-min fairness criterion.


title: Streaming Verification of Graph Properties

abstract:
  Streaming interactive proofs (SIPs) are a framework for outsourced
computation. A computationally limited streaming client (the verifier) hands
over a large data set to an untrusted server (the prover) in the cloud and the
two parties run a protocol to confirm the correctness of result with high
probability. SIPs are particularly interesting for problems that are hard to
solve (or even approximate) well in a streaming setting. The most notable of
these problems is finding maximum matchings, which has received intense
interest in recent years but has strong lower bounds even for constant factor
approximations.
  In this paper, we present efficient streaming interactive proofs that can
verify maximum matchings exactly. Our results cover all flavors of matchings
(bipartite/non-bipartite and weighted). In addition, we also present streaming
verifiers for approximate metric TSP. In particular, these are the first
efficient results for weighted matchings and for metric TSP in any streaming
verification model.


title:
Large Initial Data Global Well-Posedness for a Supercritical Wave
  Equation

abstract:
  We prove the existence of global solutions to the focusing
energy-supercritical semilinear wave equation in R^{3+1} for arbitrary outgoing
large initial data, after we modify the equation by projecting the nonlinearity
on outgoing states.


title: Exact solutions in f(R) theory of gravity

abstract:
  We find a new method for looking for the static and spherically symmetric
solutions in $F(R)$ theory of gravity. With this method, a number of new
solutions in terms of the analytic functions are obtained. We hope this
investigation may be of some help in the searching for some other solutions in
$F(R)$ theory of gravity.


title: Symmetry breaking patterns of the 3-3-1 model at finite temperature

abstract:
  We consider the minimal version of an extension of the standard electroweak
model based on the $SU(3)_c \times SU(3)_L \times U(1)_X$ gauge symmetry (the
3-3-1 model). We analyze the most general potential constructed from three
scalars in the triplet representation of $SU(3)_L$, whose neutral components
develop nonzero vacuum expectation values, giving mass for all the model's
massive particles. {}For different choices of parameters, we obtain the
particle spectrum for the two symmetry breaking scales: one where the $SU(3)_L
\times U(1)_X$ group is broken down to $SU(2)_L\times U(1)_Y$ and a lower scale
similar to the standard model one. Within the considerations used, we show that
the model encodes two first-order phase transitions, respecting the pattern of
symmetry restoration. The last transition, corresponding to the standard
electroweak one, is found to be very weak first-order, most likely turning
second-order or a crossover in practice. However, the first transition in this
model can be strongly first-order, which might happen at a temperature not too
high above the second one. We determine the respective critical temperatures
for symmetry restoration for the model.


title:
An Exponential Separation Between Randomized and Deterministic
  Complexity in the LOCAL Model

abstract:
  Over the past 30 years numerous algorithms have been designed for symmetry
breaking problems in the LOCAL model, such as maximal matching, MIS, vertex
coloring, and edge-coloring. For most problems the best randomized algorithm is
at least exponentially faster than the best deterministic algorithm. In this
paper we prove that these exponential gaps are necessary and establish
connections between the deterministic and randomized complexities in the LOCAL
model. Each result has a very compelling take-away message:
  1. Fast $\Delta$-coloring of trees requires random bits: Building on the
recent lower bounds of Brandt et al., we prove that the randomized complexity
of $\Delta$-coloring a tree with maximum degree $\Delta\ge 55$ is
$\Theta(\log_\Delta\log n)$, whereas its deterministic complexity is
$\Theta(\log_\Delta n)$ for any $\Delta\ge 3$. This also establishes a large
separation between the deterministic complexity of $\Delta$-coloring and
$(\Delta+1)$-coloring trees.
  2. Randomized lower bounds imply deterministic lower bounds: We prove that
any deterministic algorithm for a natural class of problems that runs in
$O(1)+o(\log_\Delta n)$ rounds can be transformed to run in
$O(\log^*n-\log^*\Delta+1)$ rounds. If the transformed algorithm violates a
lower bound (even allowing randomization), then one can conclude that the
problem requires $\Omega(\log_\Delta n)$ time deterministically.
  3. Deterministic lower bounds imply randomized lower bounds: We prove that
the randomized complexity of any natural problem on instances of size $n$ is at
least its deterministic complexity on instances of size $\sqrt{\log n}$. This
shows that a deterministic $\Omega(\log_\Delta n)$ lower bound for any problem
implies a randomized $\Omega(\log_\Delta\log n)$ lower bound. It also
illustrates that the graph shattering technique is absolutely essential to the
LOCAL model.


title: SXDF-ALMA 2 arcmin$^2$ Deep Survey: 1.1-mm Number Counts

abstract:
  We report 1.1 mm number counts revealed with the Atacama Large
Millimeter/submillimeter Array (ALMA) in the Subaru/XMM-Newton Deep Survey
Field (SXDF). The advent of ALMA enables us to reveal millimeter-wavelength
number counts down to the faint end without source confusion. However, previous
studies are based on the ensemble of serendipitously-detected sources in fields
originally targeting different sources and could be biased due to the
clustering of sources around the targets. We derive number counts in the flux
range of 0.2-2 mJy by using 23 (>=4sigma) sources detected in a continuous 2.0
arcmin$^2$ area of the SXDF. The number counts are consistent with previous
results within errors, suggesting that the counts derived from
serendipitously-detected sources are not significantly biased, although there
could be field-to-field variation due to the small survey area. By using the
best-fit function of the number counts, we find that ~40% of the extragalactic
background light at 1.1 mm is resolved at S(1.1mm) > 0.2 mJy.


title: Can decaying sterile neutrinos account for all dark matter?

abstract:
  The recent discovery of unexplained X-ray line of $3.5-3.6$ keV emitted from
the Perseus cluster of galaxies and M31 and the excess X-ray line of $8.7$ keV
emitted from the Milky Way center may indicate that dark matter would decay. In
this article, I show that approximately 80 \% of dark matter being 7.1 keV
sterile neutrinos and 20 \% of dark matter being 17.4 keV sterile neutrinos can
satisfactorily explain the observed X-ray lines and account for all missing
mass. No free parameter is needed in this model. This scenario is also
compatible with current robust observational constraints from the matter power
spectrum in large-scale structures and would alleviate the challenges faced by
the existing dark matter models.


title:
A class of q-orthogonal polynomial sequences that extends the q-Askey
  scheme

abstract:
  We obtain new explicit formulas for the recurrence coefficients of the
q-orthogonal polynomial sequences in a class that extends the q-Askey scheme.
  Our formulas express the recurrence coefficients in terms of four parameters
that determine the zeroes and poles. By direct substitution of particular
values for the four parameters we obtain all the polynomial sequences in the
q-Askey scheme, including the Askey-Wilson and the Racah polynomials. We also
obtain some families of sequences that may be new.


title:
Electron Acceleration at a Coronal Shock Propagating Through a
  Large-scale Streamer-like Magnetic Field

abstract:
  With a test-particle simulation, we investigate the effect of large-scale
coronal magnetic fields on electron acceleration at an outward-propagating
coronal shock with a circular front. The coronal field is approximated by an
analytical solution with a streamer-like magnetic field featured by partially
open magnetic field and a current sheet at the equator atop the closed region.
We show that the large-scale shock-field configuration, especially the relative
curvature of the shock and the magnetic field line across which the shock is
sweeping, plays an important role in the efficiency of electron acceleration.
At low shock altitudes, when the shock curvature is larger than that of
magnetic field lines, the electrons are mainly accelerated at the shock flanks;
at higher altitudes, when the shock curvature is smaller, the electrons are
mainly accelerated at the shock nose around the top of closed field lines. The
above process reveals the shift of efficient electron acceleration region along
the shock front during its propagation. It is also found that in general the
electron acceleration at the shock flank is not so efficient as that at the top
of closed field since at the top a collapsing magnetic trap can be formed. In
addition, we find that the energy spectra of electrons is power-law like, first
hardening then softening with the spectral index varying in a range of -3 to
-6. Physical interpretations of the results and implications on the study of
solar radio bursts are discussed.


title: Hydrodynamic theory of quantum fluctuating superconductivity

abstract:
  A hydrodynamic theory of transport in quantum mechanically phase-disordered
superconductors is possible when supercurrent relaxation can be treated as a
slow process. We obtain general results for the frequency-dependent
conductivity of such a regime. With time-reversal invariance, the conductivity
is characterized by a Drude-like peak, with width given by the supercurrent
relaxation rate. Using the memory matrix formalism, we obtain a formula for
this width (and hence also the dc resistivity) when the supercurrent is relaxed
by short range Coulomb interactions. This leads to a new -- effective field
theoretic and fully quantum -- derivation of a classic result on flux flow
resistance. With strong breaking of time-reversal invariance, the optical
conductivity exhibits what we call a `hydrodynamic supercyclotron' resonance.
We obtain the frequency and decay rate of this resonance for the case of
supercurrent relaxation due to an emergent Chern-Simons gauge field. The
supercurrent decay rate in this `topologically ordered superfluid vortex
liquid' is determined by the conductivities of the normal component of the
liquid. Our work gives a controlled framework for low temperature metallic
phases arising from phase-disordered superconductivity.


title:
Tricritical Ising phase transition in two-ladder Majorana fermion
  lattice

abstract:
  We introduce a two-ladder lattice model with interacting Majorana fermions
that could be realized on the surfaces of a topological insulator film. We
study this model by a combination of analytical and numerical techniques and
find a phase diagram that features both gapless and gapped phases as well as
interesting phase transitions including a quantum critical point in the
tricritical Ising (TCI) universality class. The latter occurs at an
intermediate coupling strength at a meeting point of a first-order transition
line and an Ising critical line and is known to be described by a
superconformal field theory with central charge $c =\frac{7}{10}$. We discuss
the experimental feasibility of constructing the model and tuning parameters to
the vicinity of the TCI point where signatures of the elusive supersymmetry can
be observed.


title:
Surface Kondo Effect and Non-Trivial Metallic State of the Kondo
  Insulator YbB12

abstract:
  A synergistic effect between strong electron correlation and spin-orbit
interaction (SOI) has been theoretically predicted to result in a new
topological state of quantum matter on Kondo insulators (KIs), so-called
topological Kondo insulators (TKIs). One TKI candidate has been experimentally
observed on the KI SmB6(001), and the origin of the surface states (SS) and the
topological order of SmB6 has been actively discussed. Here, we show a metallic
SS on the clean surface of another TKI candidate YbB12(001), using
angle-resolved photoelectron spectroscopy. The SS showed temperature-dependent
reconstruction corresponding with the Kondo effect observed for bulk states.
Despite the low-temperature insulating bulk, the reconstructed SS with c-f
hybridization was metallic, forming a closed Fermi contour surrounding
$\bar{\Gamma}$ on the surface Brillouin zone and agreeing with the
theoretically expected behavior for SS on TKIs. These results demonstrate the
temperature-dependent holistic reconstruction of two-dimensional states
localized on KIs surface driven by the Kondo effect.


title:
Spin dynamics, electronic and thermal transport properties of
  two-dimensional CrPS4 single crystal

abstract:
  2-Dimensional (2D) CrPS4 single crystals have been grown by the chemical
vapor transport method. The crystallographic, magnetic, electronic and thermal
transport properties of the single crystals were investigated by the
room-temperature X-ray diffraction, electrical resistivity \r{ho}(T), specific
heat CP(T) and the electronic spin response (ESR) measurements. CrPS4 crystals
crystallize into a monoclinic structure. The electrical resistivity \r{ho}(T)
shows a semiconducting behavior with an energy gap Ea=0.166 eV. The
antiferromagntic (AFM) transition temperature is about TN=36 K. The spin
flipping induced by the applied magnetic field is observed along the c axis.
The magnetic phase diagram of CrPS4 single crystal has been discussed. The
extracted magnetic entropy at TN is about 10.8 J/mol K, which is consistent
with the theoretical value R ln(2S + 1) for S = 3/2 of the Cr3+ ion. Based on
the mean-field theory, the magnetic exchange constants J1 and Jc corresponding
to the interactions of the intralayer and between layers are about 0.143 meV
and -0.955 meV are obtained based on the fitting of the susceptibility above
TN, which agree with the results obtained from the ESR measurements. With the
help of the strain for tuning the magnetic properties, monolayer CrPS4 may be a
promising candidate to explore 2D magnetic semiconductors.


title:
Scalar Green Function Bounds for Instantaneous Shock Location and
  One-dimensional Stability of Viscous Shock Waves

abstract:
  In this paper, we investigate and prove the nonlinear stability of viscous
shock wave solutions of a scalar viscous conservation law, using the methods
developed for general systems of conservation laws by Howard, Mascia, Zumbrun
and others, based on instantaneous tracking of the location of the perturbed
viscous shock wave. In some sense, this paper extends the treatment in a
previous expository work of Zumbrun ["Instantaneous shock location ..."] on
Burgers equation to the general case, giving an exposition of these methods in
the simplest setting of scalar equations. In particular we give by a rescaling
argument a simple treatment of nonlinear stability in the small-amplitude case.


title: Point-wise Stability of Reaction Diffusion Fronts

abstract:
  Using pointwise semigroup techniques, we establish sharp rates of decay in
space and time of a perturbed reaction diffusion front to its time-asymptotic
limit. This recovers results of Sattinger, Henry and others of time-exponential
convergence in weighted $L^p$ and Sobolev norms, while capturing the new
feature of spatial diffusion at Gaussian rate. Novel features of the argument
are a point-wise Green function decomposition reconciling spectral
decomposition and short-time Nash-Aronson estimates and an instantaneous
tracking scheme similar to that used in the study of stability of viscous shock
waves.


title: Fidelity of density operator in an operator-algebraic framework

abstract:
  Josza's definition of fidelity for a pair of (mixed) quantum states is
studied in the context of two types of operator algebras. The first setting is
mainly algebraic in that it involves unital C$^*$-algebras $A$ that possess a
faithful trace functional $\tau$. In this context, the role of quantum states
(that is, density operators) in the classical quantum-mechanical framework is
assumed by positive elements $\rho\in A$ for which $\tau(\rho)=1$. The second
of our two settings is more operator theoretic: by fixing a faithful normal
semifinite trace $\tau$ on a semifinite von Neumann algebra $M$, we define and
consider the fidelity of pairs of positive operators in $M$ of unit trace. The
main results of this paper address monotonicity and preservation of fidelity
under the action of certain trace-preserving positive linear maps of $A$ or of
the predual $M_*$. Our results also yield a new proof of a theorem of Moln\'ar
on the structure of quantum channels on the trace-class operators that preserve
fidelity.


title: Magnetic evolution of Spinel Mn1-xZnxCr2O4 single crystals

abstract:
  Mn1-xZnxCr2O4 (0<x<1) single crystals have been grown by the chemical vapor
transport (CVT) method. The crystallographic, magnetic, and thermal transport
properties of the single crystals were investigated by the room-temperature
X-ray diffraction, magnetization M(T) and specific heat CP(T) measurements.
Mn1-xZnxCr2O4 crystals show a cubic structure, the lattice constant a decreases
with the increasing content x of the doped Zn2+ ions and follows the Vegard
law. Based on the magnetization and heat capacity measurements, the magnetic
evolution of Mn1-xZnxCr2O4 crystals has been discussed. For 0<x<0.3, the
magnetic ground state is the coexistence of the collinear ferrimagnetic order
(CFIM) and spiral ferrimagnetic one (SFIM), which is similar to that of the
parent MnCr2O4. When x changes from 0.3 to 0.8, the SFIM is progressively
suppressed and spin glass-like behavior is observed. When x is above 0.8, an
antiferromagnetic (AFM) order presents. At the same time, the magnetic specific
heat (Cmag.) was also investigated and the results are coincident with the
magnetic measurements. The possible reasons based on the disorder effect and
the reduced molecular field effect induced by the substitution of Mn2+ ions by
nonmagnetic Zn2+ ones in Mn1-xZnxCr2O4 crystals have been discussed.


title:
The complexity of the topological conjugacy problem for Toeplitz
  subshifts

abstract:
  In this paper, we analyze the Borel complexity of the topological conjugacy
relation on Toeplitz subshifts. More specifically, we prove that topological
conjugacy of Toeplitz subshifts with separated holes is hyperfinite. Indeed, we
show that the topological conjugacy relation is hyperfinite on a larger class
of Toeplitz subshifts which we call Toeplitz subshifts with growing blocks.
This result provides a partial answer to a question asked by Sabok and Tsankov.


title:
Curvilinear coordinates on generic conformally flat hypersurfaces and
  constant curvature 2-metrics

abstract:
  There is a one-to-one correspondence between associated families of generic
conformally flat (local-)hypersurfaces in 4-dimensional space forms and
conformally flat 3-metrics with the Guichard condition. In this paper, we study
the space of conformally flat 3-metrics with the Guichard condition: for a
conformally flat 3-metric with the Guichard condition in the interior of the
space, an evolution of orthogonal (local-) Riemannian $2$-metrics with constant
Gauss curvature $-1$ is determined; for a $2$-metric belonging to a certain
class of orthogonal analytic $2$-metrics with constant Gauss curvature $-1$, a
one-parameter family of conformally flat 3-metrics with the Guichard condition
is determined as evolutions issuing from the $2$-metric.


title: Ratios and Cauchy Distribution

abstract:
  It is well known that the ratio of two independent standard Gaussian random
variables follows a Cauchy distribution. Any convex combination of independent
standard Cauchy random variables also follows a Cauchy distribution. In a
recent joint work, the author proved a surprising multivariate generalization
of the above facts. Fix $m > 1$ and let $\Sigma$ be a $m\times m$ positive
semi-definite matrix. Let $X,Y \sim \mathrm{N}(0,\Sigma)$ be independent
vectors. Let $\vec{w}=(w_1, \dots, w_m)$ be a vector of non-negative numbers
with $\sum_{j=1}^m w_j = 1.$ The author proved recently that the random
variable $$ Z = \sum_{j=1}^m w_j\frac{X_j}{Y_j}\; $$ also has the standard
Cauchy distribution. In this note, we provide some more understanding of this
result and give a number of natural generalizations. In particular, we observe
that if $(X,Y)$ have the same marginal distribution, they need neither be
independent nor be jointly normal for $Z$ to be Cauchy distributed. In fact,
our calculations suggest that joint normality of $(X,Y)$ may be the only
instance in which they can be independent. Our results also give a method to
construct copulas of Cauchy distributions.


title: Electron optics with ballistic graphene junctions

abstract:
  Electrons transmitted across a ballistic semiconductor junction undergo
refraction, analogous to light rays across an optical boundary. A pn junction
theoretically provides the equivalent of a negative index medium, enabling
novel electron optics such as negative refraction and perfect (Veselago)
lensing. In graphene, the linear dispersion and zero-gap bandstructure admit
highly transparent pn junctions by simple electrostatic gating, which cannot be
achieved in conventional semiconductors. Moreover ballistic transport over
micron length scales at ambient temperature has been realized, providing an
ideal platform to realize a new generation of device based on electron lensing.
Robust demonstration of these effects, however, has not been forthcoming. Here
we employ transverse magnetic focusing to probe propagation across an
electrostatically defined graphene junction. We find perfect agreement with the
predicted Snells law for electrons, including observation of both positive and
negative refraction. Resonant transmission across the pn junction provides a
direct measurement of the angle dependent transmission coefficient, and we
demonstrate good agreement with theory. Comparing experimental data with
simulation reveals the crucial role played by the effective junction width,
providing guidance for future device design. Our results pave the way for
realizing novel electron optics based on graphene pn junctions.


title: Non-Identifiable Pedigrees and a Bayesian Solution

abstract:
  Some methods aim to correct or test for relationships or to reconstruct the
pedigree, or family tree. We show that these methods cannot resolve ties for
correct relationships due to identifiability of the pedigree likelihood which
is the probability of inheriting the data under the pedigree model. This means
that no likelihood-based method can produce a correct pedigree inference with
high probability. This lack of reliability is critical both for health and
forensics applications.
  In this paper we present the first discussion of multiple typed individuals
in non-isomorphic pedigrees, $\mathcal{P}$ and $\mathcal{Q}$, where the
likelihoods are non-identifiable, $Pr[G~|~\mathcal{P},\theta] =
Pr[G~|~\mathcal{Q},\theta]$, for all input data $G$ and all recombination rate
parameters $\theta$. While there were previously known non-identifiable pairs,
we give an example having data for multiple individuals.
  Additionally, deeper understanding of the general discrete structures driving
these non-identifiability examples has been provided, as well as results to
guide algorithms that wish to examine only identifiable pedigrees. This paper
introduces a general criteria for establishing whether a pair of pedigrees is
non-identifiable and two easy-to-compute criteria guaranteeing identifiability.
Finally, we suggest a method for dealing with non-identifiable likelihoods: use
Bayes rule to obtain the posterior from the likelihood and prior. We propose a
prior guaranteeing that the posterior distinguishes all pairs of pedigrees.
  Shortened version published as: B. Kirkpatrick. Non-identifiable pedigrees
and a Bayesian solution. Int. Symp. on Bioinformatics Res. and Appl. (ISBRA),
7292:139-152 2012.


title: EP elements in rings with involution

abstract:
  Let $R$ be a unital ring with involution. We first show that the EP elements
in $R$ can be characterized by three equations. Namely, let $a\in R$, then $a$
is EP if and only if there exists $x\in R$ such that $(xa)^{\ast}=xa$,
$xa^{2}=a$ and $ax^{2}=x.$ It is well known that all EP elements in $R$ are
core invertible and Moore-Penrose invertible. We give more equivalent
conditions for a core (Moore-Penrose) invertible element to be an EP element.
Finally, the EP elements are characterized in terms of $n$-EP property, which
is a generalization of bi-EP property.


title:
Extension spectrale d'un signal de parole de la bande t\'el\'ephonique
  \`a la bande AM

abstract:
  This document proposes a bandwidth extension system producing a wideband
signal from a narrowband speech signal. The extension is performed
independently for high and low frequencies. High-frequency extension uses the
excitation-filter model. Extension of the excitation is performed in the time
domain using a non-linear function, while the spectral envelope is extended in
the cepstral domain using a multi-layer perceptron. Low-band extension is based
on the sinusoidal model. The amplitude of sinusoids is also estimated using a
multi-layer perceptron.
  The results show that the sound quality after extension is higher than that
of narrowband speech, with a significant variation across listeners. Some of
the techniques, including excitation extension, are of interest in the field of
speech coding.
  -----
  Le pr\'esent m\'emoire propose un syst\`eme d'extension de la bande
permettant de produire un signal en bande AM \`a partir d'un signal de parole
en bande t\'el\'ephonique. L'extension est effectu\'ee de fa\c{c}on
ind\'ependante pour les hautes fr\'equences et les basses fr\'equences.
L'extension des hautes fr\'equences utilise le mod\`ele filtre-excitation.
L'extension de l'excitation est r\'ealis\'ee dans le domaine temporel par une
fonction non lin\'eaire, alors que l'extension de l'enveloppe spectrale
s'effectue dans le domaine cepstral par un perceptron multi-couches.
L'extension de la bande basse utilise le mod\`ele sinuso\"idal. L'amplitude des
sinuso\"ides est aussi estim\'ee par un perceptron multi-couches.
  Les r\'esultats obtenus montrent que la qualit\'e sonore apr\`es extension
est sup\'erieure \`a celle de la bande t\'el\'ephonique, avec une importante
diff\'erence entre les auditeurs. Certaines techniques d\'evelopp\'ees, dont
l'extension de l'excitation, pr\'esentent un certain int\'er\^et pour le
domaine du codage de la parole.


title: Search by Ideal Candidates: Next Generation of Talent Search at LinkedIn

abstract:
  One key challenge in talent search is how to translate complex criteria of a
hiring position into a search query. This typically requires deep knowledge on
which skills are typically needed for the position, what are their
alternatives, which companies are likely to have such candidates, etc. However,
listing examples of suitable candidates for a given position is a relatively
easy job. Therefore, in order to help searchers overcome this challenge, we
design a next generation of talent search paradigm at LinkedIn: Search by Ideal
Candidates. This new system only needs the searcher to input one or several
examples of suitable candidates for the position. The system will generate a
query based on the input candidates and then retrieve and rank results based on
the query as well as the input candidates. The query is also shown to the
searcher to make the system transparent and to allow the searcher to interact
with it. As the searcher modifies the initial query and makes it deviate from
the ideal candidates, the search ranking function dynamically adjusts an
refreshes the ranking results balancing between the roles of query and ideal
candidates. As of writing this paper, the new system is being launched to our
customers.


title:
Critical properties of dissipative quantum spin systems in finite
  dimensions

abstract:
  We study the critical properties of finite-dimensional dissipative quantum
spin systems with uniform ferromagnetic interactions. Starting from the
transverse-field Ising model coupled to a bath of harmonic oscillators with
Ohmic spectral density, we generalize its classical representation to classical
spin systems with $O(n)$ symmetry and then take the large-$n$ limit to reduce
the system to the spherical model. The exact solution to the resulting
spherical model with long-range interactions along the imaginary-time axis
shows a phase transition with static critical exponents coinciding with those
of the conventional short-range spherical model in $d+2$ dimensions, where $d$
is the spatial dimensionality of the original quantum system. This implies the
dynamical exponent to be $z=2$. These conclusions are consistent with the
results of Monte Carlo simulations and renormalization group calculations for
dissipative transverse-field Ising and $O(n)$ models in one and two dimensions.
The present approach therefore serves as a useful tool to analytically
investigate the properties of quantum phase transitions of the dissipative
transverse-field Ising and related models. Our method may also offer a platform
to study more complex phase transitions in dissipative finite-dimensional
quantum spin systems, which recently receive renewed interest under the context
of quantum annealing in a noisy environment.


title:
Effects of beam velocity and density on an ion-beam pulse moving in
  magnetized plasmas

abstract:
  The wakefield and stopping power of an ion-beam pulse moving in magnetized
plasmas are investigated by particle-in-cell (PIC) simulations. The effects of
beam velocity and density on the wake and stopping power are discussed. In the
presence of magnetic field, it is found that beside the longitudinal conversed
V-shaped wakes, the strong whistler wave are observed when low-density and
low-velocity pulses moving in plasmas. The corresponding stopping powers are
enhanced due to the drag of these whistler waves. As beam velocities increase,
the whistler waves disappear, and only are conversed V-shape wakes observed.
The corresponding stopping powers are reduced compared with these in isotropic
plasmas. When high-density pulses transport in the magnetized plasmas, the
whistler waves are greatly inhibited for low-velocity pulses and disappear for
high-velocity pulses. Additionally, the magnetic field reduces the stopping
powers for all high-density cases.


title:
Hyperfine-induced electric dipole contributions to the electric octupole
  and magnetic quadrupole atomic clock transitions

abstract:
  Hyperfine-induced electric dipole contributions may significantly increase
probabilities of otherwise very weak electric octupole and magnetic quadrupole
atomic clock transitions (e.g. transitions between $s$ and $f$ electron
orbitals). These transitions can be used for exceptionally accurate atomic
clocks, quantum information processing and search for dark matter. They are
very sensitive to new physics beyond the Standard Model, such as temporal
variation of the fine structure constant, the Lorentz invariance and Einstein
equivalence principle violation. We formulate conditions under which the
hyperfine-induced electric dipole contribution dominates. Due to the hyperfine
quenching the electric octupole clock transition in $^{173}$Yb$^+$ is two
orders of magnitude stronger than that in currently used $^{171}$Yb$^+$. Some
enhancement is found in $^{143}$Nd$^{13+}$, $^{149}$Pm$^{14+}$,
$^{147}$Sm$^{14+}$, and $^{147}$Sm$^{15+}$ ions.


title:
Ionization potentials and polarizabilities of superheavy elements from
  Db to Cn ($Z$=105 to 112)

abstract:
  Relativistic Hartree-Fock and random phase approximation methods for open
shells are used to calculate ionization potentials and static scalar
polarizabilities of eight superheavy elements with open $6d$-shell, which
include Db, Sg, Bh, Hs, Mt, Ds, Rg and Cn ($Z$=105 to 112). Inter-electron
correlations are taken into account with the use of the semi-empirical
polarization potential. Its parameters are chosen to fit the known ionization
potentials of lighter atoms. Calculations for lighter atoms are also used to
illustrate the accuracy of the approach.


title:
DeepSpark: A Spark-Based Distributed Deep Learning Framework for
  Commodity Clusters

abstract:
  The increasing complexity of deep neural networks (DNNs) has made it
challenging to exploit existing large-scale data processing pipelines for
handling massive data and parameters involved in DNN training. Distributed
computing platforms and GPGPU-based acceleration provide a mainstream solution
to this computational challenge. In this paper, we propose DeepSpark, a
distributed and parallel deep learning framework that exploits Apache Spark on
commodity clusters. To support parallel operations, DeepSpark automatically
distributes workloads and parameters to Caffe/Tensorflow-running nodes using
Spark, and iteratively aggregates training results by a novel lock-free
asynchronous variant of the popular elastic averaging stochastic gradient
descent based update scheme, effectively complementing the synchronized
processing capabilities of Spark. DeepSpark is an on-going project, and the
current release is available at http://deepspark.snu.ac.kr.


title:
Epitaxially Stabilized Oxide Composed of Twisted Triangular-Lattice
  Layers

abstract:
  Layered oxides have been intensively studied due to their high designability
for various electronic functions. Here we synthesize a new oxide as epitaxial
thin film form by pulsed laser deposition. Film characterizations including
cross-section and plan-view transmission electron microscopy confirm that the
film is composed of twisted stack of triangular-lattice Rh and Bi layers. We
foresee that the concept of twisted oxide layers will open up a new route to
design further functional layered oxides.


title:
BCS, Nambu-Jona-Lasinio, and Han-Nambu -- A sketch of Nambu's works in
  1960-1965

abstract:
  The years of 1960-1965 were a remarkable period for Yoichiro Nambu. Starting
with a reformulation of BCS theory with emphasis on gauge invariance, he
recognized the realization of spontaneous chiral symmetry breaking in particle
physics as is evidenced by the Goldberger-Treiman relation. A concrete model of
Nambu and Jona-Lasinio illustrated the essence of the Nambu-Goldstone theorem
and the idea of soft pions. After the proposal of the quark model by Gell-Mann,
he together with Han constructed an alternative model of integrally charged
quarks with possible non-Abelian gluons. All those remarkable works were
performed during the years 1960-1965. Here I briefly review those works
following the original papers of Nambu chronologically, together with a brief
introduction to a formulation of Neother's theorem and Ward-Takahashi
identities using path integrals. This article is mostly based on a lecture
given at the Nambu Memorial Symposium held at Osaka City University in
September 2015, where Nambu started his professional career.


title: Scalable and Sustainable Deep Learning via Randomized Hashing

abstract:
  Current deep learning architectures are growing larger in order to learn from
complex datasets. These architectures require giant matrix multiplication
operations to train millions of parameters. Conversely, there is another
growing trend to bring deep learning to low-power, embedded devices. The matrix
operations, associated with both training and testing of deep networks, are
very expensive from a computational and energy standpoint. We present a novel
hashing based technique to drastically reduce the amount of computation needed
to train and test deep networks. Our approach combines recent ideas from
adaptive dropouts and randomized hashing for maximum inner product search to
select the nodes with the highest activation efficiently. Our new algorithm for
deep learning reduces the overall computational cost of forward and
back-propagation by operating on significantly fewer (sparse) nodes. As a
consequence, our algorithm uses only 5% of the total multiplications, while
keeping on average within 1% of the accuracy of the original model. A unique
property of the proposed hashing based back-propagation is that the updates are
always sparse. Due to the sparse gradient updates, our algorithm is ideally
suited for asynchronous and parallel training leading to near linear speedup
with increasing number of cores. We demonstrate the scalability and
sustainability (energy efficiency) of our proposed algorithm via rigorous
experimental evaluations on several real datasets.


title:
Effects of periodic kicking on dispersion and wave packet dynamics in
  graphene

abstract:
  We study the effects of $\delta$-function periodic kicks on the Floquet
energy-momentum dispersion in graphene. We find that a rich variety of
dispersions can appear depending on the parameters of the kicking: at certain
points in the Brillouin zone, the dispersion can become linear but anisotropic,
linear in one direction and quadratic in the perpendicular direction, gapped
with a quadratic dispersion, or completely flat (called dynamical
localization). We show all these results analytically and demonstrate them
numerically through the dynamics of wave packets propagating in graphene. We
propose experimental methods for producing these effects.


title:
Disk Polarization From Both Emission and Scattering of Magnetically
  Aligned Grains: The Case of NGC 1333 IRAS4A1

abstract:
  Dust polarization in millimeter (and centimeter) has been mapped in disks
around an increasing number of young stellar objects. It is usually thought to
come from emission by magnetically aligned (non-spherical) grains, but can also
be produced by dust scattering. We present a semi-analytic theory of disk
polarization that includes both the direction emission and scattering, with an
emphasis on their relative importance and how they are affected by the disk
inclination. For face-on disks, both emission and scattering tend to produce
polarization in the radial direction, making them difficult to distinguish,
although the scattering-induced polarization can switch to the azimuthal
direction if the incident radiation is beamed strongly enough in the radial
direction in the disk plane. Disk inclination affects the polarizations from
emission and scattering differently, especially on the major axis where, in the
edge-on limit, the former vanishes while the latter reaches a polarization
fraction as large as 1/3. The polarizations from the two competing mechanisms
tend to cancel each other on the major axis, producing two low polarization
"holes" (one on each side of the center) under certain conditions. We find
tantalizing evidence for at least one such "hole" in NGC1333 IRAS4A1, whose
polarization observed at 8 mm on the 100 AU scale is indicative of a pattern
dominated by scattering close to the center and by direction emission in the
outer region. If true, it would imply not only that a magnetic field exists on
the disk scale, but that it is strong enough to align large, possibly mm-sized,
grains.


title: Force distribution in a semiflexible loop

abstract:
  Loops undergoing thermal fluctuations are prevalent in nature. Ring-like or
cross-linked polymers, cyclic macromolecules, and protein-mediated DNA loops
all belong to this category. Stability of these molecules are generally
described in terms of free energy, an average quantity, but it may also be
impacted by local fluctuating forces acting within these systems. The full
distribution of these forces can thus give us insights into mechanochemistry
beyond the predictive capability of thermodynamics. In this paper, we study the
force exerted by an inextensible semiflexible polymer constrained in a looped
state. By using a novel simulation method termed "phase-space sampling", we
generate the equilibrium distribution of chain conformations in both position
and momentum space. We compute the constraint forces between the two ends of
the loop in this chain ensemble using Lagrangian mechanics, and show that the
mean of these forces is equal to the thermodynamic force. By analyzing kinetic
and potential contributions to the forces, we find that the mean force acts in
the direction of increasing extension not because of bending stress, but in
spite of it. Furthermore, we obtain a distribution of constraint forces as a
function of chain length, extension, and stiffness. Notably, increasing contour
length decreases the average force, but the additional freedom allows
fluctuations in the constraint force to increase. The force distribution is
asymmetric and falls off less sharply than a Gaussian distribution. Our work
exemplifies a system where large-amplitude fluctuations occur in a way
unforeseen by a purely thermodynamic framework, and offers novel computational
tools useful for efficient, unbiased simulation of a constrained system.


title:
Floating up of the zero-energy Landau level in monolayer epitaxial
  graphene

abstract:
  We report on magneto-transport measurements on low-density, large-area
monolayer epitaxial graphene devices grown on SiC. We show that the zero-energy
Landau level (LL) in monolayer graphene, which is predicted to be magnetic
field ($B$)-independent, can float up above the Fermi energy at low $B$. This
is supported by the temperature ($T$)-driven flow diagram approximated by the
semi-circle law as well as the $T$-independent point in the Hall conductivity
$\sigma_{xy}$ near $e^2/h$. Our experimental data are in sharp contrast to
conventional understanding of the zeroth LL and metallic-like behavior in
pristine graphene prepared by mechanical exfoliation at low $T$. This
surprising result can be ascribed to substrate-induced sublattice symmetry
breaking which splits the degeneracy of the zeroth Landau level. Our finding
provides a unified picture regarding the metallic behavior in pristine graphene
prepared by mechanical exfoliation, and the insulating behavior and the
insulator-quantum Hall transition in monolayer epitaxial graphene.


title: Category Theoretic Analysis of Photon-based Decision Making

abstract:
  Decision making is a vital function in this age of machine learning and
artificial intelligence, yet its physical realization and theoretical
fundamentals are still not completely understood. In our former study, we
demonstrated that single-photons can be used to make decisions in uncertain,
dynamically changing environments. The two-armed bandit problem was
successfully solved using the dual probabilistic and particle attributes of
single photons. In this study, we present a category theoretic modeling and
analysis of single-photon-based decision making, including a quantitative
analysis that is in agreement with the experimental results. A category
theoretic model reveals the complex interdependencies of subject matter
entities in a simplified manner, even in dynamically changing environments. In
particular, the octahedral and braid structures in triangulated categories
provide a better understanding and quantitative metrics of the underlying
mechanisms of a single-photon decision maker. This study provides both insight
and a foundation for analyzing more complex and uncertain problems, to further
machine learning and artificial intelligence.


title:
Relativistic coupled-cluster study of RaF as a candidate for parity and
  time reversal violating interaction

abstract:
  We have employed both Z-vector method and the expectation value approach in
the relativistic coupled-cluster framework to calculate the scalar-pseudoscalar
(S-PS) P, T -odd interaction constant (W_s) and the effective electric field
(Eeff) experienced by the unpaired electron in the ground electronic state of
RaF. Further, the magnetic hyperfine structure constants of ^{223}Ra in RaF and
^{223}Ra+ are also calculated and compared with the experimental values
wherever available to judge the extent of accuracy obtained in the employed
methods. The outcome of our study reveals that the Z-vector method is superior
than the expectation value approach in terms of accuracy obtained for the
calculation of ground state property. The Z-vector calculation shows that RaF
has a high E_eff (52.5 GV/cm) and W_s (141.2 kHz) which makes it a potential
candidate for the eEDM experiment.


title: Relative Algebro-Geometric stabilities of Toric Manifolds

abstract:
  In this paper, we study the relative Chow and $K$-stability of toric
manifolds. First, we give a criterion for relative $K$-stability and
instability of toric Fano manifolds. The reduction of relative Chow stability
on toric manifolds will be investigated by the Hibert-Mumford criterion in two
ways. One is to consider the criterion for the maximal torus action and its
weight polytope. Then we obtain a reduction by the strategy of Ono
\cite{Ono13}, which fits into the relative GIT stability detected by
Sz\'ekelyhidi. The other way is to use the criterion for
$\mathbb{C}^{\times}$-actions and Chow weights associated to toric
degenerations following Donaldson and Ross-Thomas \cite{D02, RT07}. In the end,
we determine the relative K-stability of all toric Fano threefolds and present
a counter-example for relatively $K$-stable manifold, but which is
asymptotically relatively Chow unstable.


title:
Relativistic equation-of-motion coupled-cluster method using open-shell
  reference wavefunction

abstract:
  The open-shell reference relativistic equation-of-motion coupled-cluster
method within its four-component description is successfully implemented with
the consideration of single- and double- excitation approximation. The one-body
and two-body matrix elements required for the correlation calculation are
generated using Dirac-Coulomb Hamiltonian. As a first attempt, the implemented
method is employed to calculate a few of the low-lying ionized states of heavy
atomic (Ag, Cs, Au, Fr, Lr) and valence ionization potential of molecular (HgH,
PbF) systems, where the effect of relativity does really matter to obtain
highly accurate results. Not only the relativistic effect, but also the effect
of electron correlation is crucial in these heavy atomic and molecular systems.
To justify the fact, we have taken two further approximations in the
four-component relativistic equation-of-motion framework to quantify how the
effect of electron correlation plays a role in the calculated values at
different level of the approximation. All these calculated results are compared
with the available experimental data as well as with other theoretically
calculated values to judge the extent of accuracy obtained in our calculations.
A nice agreement is achieved for all the considered systems which validates the
performance of the open-shell reference relativistic equation-of-motion
coupled-cluster method.


title: New error term for the fourth moment of automorphic L functions

abstract:
  We improve the error term in the asymptotic formula for the twisted fourth
moment of automorphic L functions of prime level and weight two proved by
Kowalski, Michel and Vanderkam. As a consequence, we obtain a new subconvexity
bound in the level aspect and improve the lower bound on proportion of
simultaneous non-vanishing.


title: On Distributed Computing for Functions with Certain Structures

abstract:
  The problem of distributed function computation is studied, where functions
to be computed is not necessarily symbol-wise. A new method to derive a
converse bound for distributed computing is proposed; from the structure of
functions to be computed, information that is inevitably conveyed to the
decoder is identified, and the bound is derived in terms of the optimal rate
needed to send that information. The class of informative functions is
introduced, and, for the class of smooth sources, the optimal rate for
computing those functions is characterized. Furthermore, for i.i.d. sources
with joint distribution that may not be full support, functions that are
composition of symbol-wise function and the type of a sequence are considered,
and the optimal rate for computing those functions is characterized in terms of
the hypergraph entropy. As a byproduct, our method also provides a conceptually
simple proof of the known fact that computing a Boolean function may require as
large rate as reproducing the entire source.


title:
Eigenanalysis of morphological diversity in silicon random
  nanostructures formed via resist collapse

abstract:
  This paper demonstrates eigenanalysis to quantitatively reveal the diversity
and capacity of identities offered by the morphological diversity in silicon
nanostructures formed via random collapse of resist. The analysis suggests that
approximately 10^115 possible identities are provided per 0.18-um^2 area of
nanostructures, indicating that nanoscale morphological signatures will be
extremely useful for future information security applications where securing
identities is critical. The eigenanalysis provides an intuitive physical
picture and quantitative characterization of the diversity of structural
fluctuations while unifying measurement stability concerns, which will be
widely applicable to other materials, devices, and system architectures.


title: Fibred Fibration Categories

abstract:
  We introduce fibred type-theoretic fibration categories which are fibred
categories between categorical models of Martin-L\"{o}f type theory. Fibred
type-theoretic fibration categories give a categorical description of logical
predicates for identity types. As an application, we show a relational
parametricity result for homotopy type theory. As a corollary, it follows that
every closed term of type of polymorphic endofunctions on a loop space is
homotopic to some iterated concatenation of a loop.


title: Learning and Free Energies for Vector Approximate Message Passing

abstract:
  Vector approximate message passing (VAMP) is a computationally simple
approach to the recovery of a signal $\mathbf{x}$ from noisy linear
measurements $\mathbf{y}=\mathbf{Ax}+\mathbf{w}$. Like the AMP proposed by
Donoho, Maleki, and Montanari in 2009, VAMP is characterized by a rigorous
state evolution (SE) that holds under certain large random matrices and that
matches the replica prediction of optimality. But while AMP's SE holds only for
large i.i.d. sub-Gaussian $\mathbf{A}$, VAMP's SE holds under the much larger
class: right-rotationally invariant $\mathbf{A}$. To run VAMP, however, one
must specify the statistical parameters of the signal and noise. This work
combines VAMP with Expectation-Maximization to yield an algorithm, EM-VAMP,
that can jointly recover $\mathbf{x}$ while learning those statistical
parameters. The fixed points of the proposed EM-VAMP algorithm are shown to be
stationary points of a certain constrained free-energy, providing a variational
interpretation of the algorithm. Numerical simulations show that EM-VAMP is
robust to highly ill-conditioned $\mathbf{A}$ with performance nearly matching
oracle-parameter VAMP.


title:
$L^p$-mapping properties for Schr\"odinger operators in open sets of
  $\mathbb R ^d$

abstract:
  Let $H_V=-\Delta +V$ be a Schr\"odinger operator on an arbitrary open set
$\Omega$ of $\mathbb R^d$, where $d \geq 3$, and $\Delta$ is the Dirichlet
Laplacian and the potential $V$ belongs to the Kato class on $\Omega$. The
purpose of this paper is to show $L^p$-boundedness of an operator
$\varphi(H_V)$ for any rapidly decreasing function $\varphi$ on $\mathbb R$.
$\varphi(H_V)$ is defined by the spectral theorem. As a by-product,
$L^p$-$L^q$-estimates for $\varphi(H_V)$ are also obtained.


title:
Atomic and electronic structure of the $\sqrt{3}$$\times$$\sqrt{3}$
  silicene phase on Ag(111): density-functional calculations

abstract:
  Density-functional theory calculations are used to verify the atomic
structure of the $\sqrt{3}$$\times$$\sqrt{3}$ silicene phase grown on the
Ag(111) surface. Recent experimental studies strongly suggested that the
previous double-layer silicene model should be replaced with a Ag-mixed
double-layer model resembling the top layers of the
Ag/Si(111)-($\sqrt{3}$$\times$$\sqrt{3}$) surface. In our calculations, the
Ag-mixed double-layer model is indeed energetically favored over the
double-layer silicene model and well reproduces the reported scanning-tunneling
microscopy and spectroscopy data. Especially, the structural origin of the
experimental band structure is clarified as the top Ag-Si mixed layer, unlike
the experimental interpretations as either a silicene layer or the Ag(111)
substrate.


title: Architectural Complexity Measures of Recurrent Neural Networks

abstract:
  In this paper, we systematically analyze the connecting architectures of
recurrent neural networks (RNNs). Our main contribution is twofold: first, we
present a rigorous graph-theoretic framework describing the connecting
architectures of RNNs in general. Second, we propose three architecture
complexity measures of RNNs: (a) the recurrent depth, which captures the RNN's
over-time nonlinear complexity, (b) the feedforward depth, which captures the
local input-output nonlinearity (similar to the "depth" in feedforward neural
networks (FNNs)), and (c) the recurrent skip coefficient which captures how
rapidly the information propagates over time. We rigorously prove each
measure's existence and computability. Our experimental results show that RNNs
might benefit from larger recurrent depth and feedforward depth. We further
demonstrate that increasing recurrent skip coefficient offers performance
boosts on long term dependency problems.


title: Onsager's Cross Coupling Effects in Gas Flows Confined to Micro-channels

abstract:
  In rarefied gases, mass and heat transport processes interfere with each
other, leading to the mechano-caloric effect and thermo-osmotic effect, which
are of interest to both theoretical study and practical applications. We employ
the unified gas-kinetic scheme to investigate these cross coupling effects in
gas flows in micro-channels. Our numerical simulations cover channels of planar
surfaces and also channels of ratchet surfaces, with Onsager's reciprocal
relation verified for both cases. For channels of planar surfaces, simulations
are performed in a wide range of Knudsen number and our numerical results show
good agreement with the literature results. For channels of ratchet surfaces,
simulations are performed for both the slip and transition regimes and our
numerical results not only confirm the theoretical prediction [Phys. Rev. Lett.
107, 164502 (2011)] for Knudsen number in the slip regime but also show that
the off-diagonal kinetic coefficients for cross coupling effects are maximized
at a Knudsen number in the transition regime. Finally, a preliminary
optimization study is carried out for the geometry of Knudsen pump based on
channels of ratchet surfaces.


title: Charged Fermion Masses and Mixing from a SU(3) Family Symmetry Model

abstract:
  Within the framework of a Beyond Standard Model (BSM) with a local $SU(3)$
family symmetry, we report an updated fit of parameters which account for the
known spectrum of quarks and charged lepton masses and the quark mixing in a
$4\times 4$ non-unitary $V_{CKM}$. In this scenario, ordinary heavy fermions,
top and bottom quarks and tau lepton, become massive at tree level from Dirac
See-saw mechanisms implemented by the introduction of a new set of $SU(2)_L$
weak singlet vector-like fermions, $U,D,E,N$, with $N$ a sterile neutrino. The
$N_{L,R}$ sterile neutrinos allow the implementation of a $8\times 8$ general
See-saw Majorana neutrino mass matrix with four massless eigenvalues at tree
level. Hence, light fermions, including neutrinos, obtain masses from loop
radiative corrections mediated by the massive $SU(3)$ gauge bosons. $SU(3)$
family symmetry is broken spontaneously in two stages, whose hierarchy of
scales yield an approximate $SU(2)$ global symmetry associated with the $Z_1,
Y_1^\pm$ gauge boson masses of the order of 2 TeV. A global fit of parameters
to include neutrino masses and lepton mixing is in progress.


title:
Robust Sound Source Localization Using a Microphone Array on a Mobile
  Robot

abstract:
  The hearing sense on a mobile robot is important because it is
omnidirectional and it does not require direct line-of-sight with the sound
source. Such capabilities can nicely complement vision to help localize a
person or an interesting event in the environment. To do so the robot auditory
system must be able to work in noisy, unknown and diverse environmental
conditions. In this paper we present a robust sound source localization method
in three-dimensional space using an array of 8 microphones. The method is based
on time delay of arrival estimation. Results show that a mobile robot can
localize in real time different types of sound sources over a range of 3 meters
and with a precision of 3 degrees.


title: Distance spectral radius of uniform hypergraphs

abstract:
  We study the effect of three types of graft transformations to increase or
decrease the distance spectral radius of uniform hypergraphs, and we determined
the unique $k$-uniform hypertrees with maximum, second maximum, minimum and
second minimum distance spectral radius, respectively.


title:
Bandwidth Extension of Narrowband Speech for Low Bit-Rate Wideband
  Coding

abstract:
  Wireless telephone speech is usually limited to the 300-3400 Hz band, which
reduces its quality. There is thus a growing demand for wideband speech systems
that transmit from 50 Hz to 8000 Hz. This paper presents an algorithm to
generate wideband speech from narrowband speech using as low as 500 bits/s of
side information. The 50-300 Hz band is predicted from the narrowband signal. A
source-excitation model is used for the 3400-8000 Hz band, where the excitation
is extrapolated at the receiver, and the spectral envelope is transmitted.
Though some artifacts are present, the resulting wideband speech has enhanced
quality compared to narrowband speech.


title:
An event mixing technique for Bose-Einstein correlations of two pions in
  photoproduction around 1 GeV

abstract:
  We have developed an event mixing technique to observe Bose-Einstein
correlations (BEC) between two identical neutral pions produced in
photo-induced reactions in the non-perturbative QCD energy region. It is found
that the missing-mass consistency cut and the pion-energy cut are essential for
the event mixing method to effectively extract BEC observables. A Monte Carlo
(MC) simulation is used to validate these constraints and confirms the
efficiency of this method. Our work paves the way for similar BEC studies at
lower energies where the multiplicity of emitted bosons is limited.


title:
Tree-wave mixing of ordinary and backward electromagnetic waves:
  extraordinary transients

abstract:
  Three-wave mixing of ordinary and backward electromagnetic waves in pulsed
regime is investigated in the metamaterials, which enable co-existence and
phase matching of such waves. It is shown that opposite direction of phase
velocity and energy flux in backward waves gives rise to extraordinary
transient processes in greatly enhanced optical parametric amplification and in
frequency up or down shifting nonlinear reflectivity. The discovered transients
resemble slowed response of an oscillator on pulsed excitation in the vicinity
of its resonance


title:
Anomalous Local Fermi Liquid in $f^{2}$-Singlet Configuration: Impurity
  Model for Heavy-Electron System UPt_3

abstract:
  It is shown by the Wilson numerical renormalization group method that a
strongly correlated impurity with a crystalline-electric-field singlet ground
state in the f^2-configuration exhibits an anomalous local Fermi liquid state
in which the static magnetic susceptibility remains an uncorrelated value while
the NMR relaxation rate is enhanced in proportion to the square of the mass
enhancement factor. Namely, the Korringa-Shiba relation is apparently broken.
This feature closely matches the anomalous behaviors observed in UPt_3, i.e.,
the coexistence of an unenhanced value of the Knight shift due to
quasiparticles contribution (the decrease across the superconducting
transition) and the enhanced relaxation rate of NMR. Such an anomalous Fermi
liquid behavior suggests that the Fermi liquid corrections for the
susceptibility are highly anisotropic.


title: Algebraic deRham cohomology of log-Riemann surfaces of finite type

abstract:
  Log-Riemann surfaces of finite type are Riemann surfaces with finitely
generated fundamental group equipped with a local diffeomorphism to C such that
the surface has finitely many infinite order ramification points. We define and
prove nondegeneracy of a period pairing for log-Riemann surfaces of finite
type, given by pairing differentials with finitely many exponential
singularities, of the form g exp(\int R_0) dz (where g, R_0 are meromorphic
functions on a compact Riemann surface, with R_0 fixed) with closed curves and
curves joining infinite order ramification points. As a consequence we show
that the dimension of a cohomology group (given by differentials with
exponential singularities of fixed type, modulo differentials of functions with
exponential singularities of the same fixed type) is finite, equal to (2g + #R
+ (n-2)), where g is the genus of the compact Riemann surface, R is the set of
infinite order ramification points, and n the number of exponential
singularities.


title: Fermion production in a magnetic field in a de Sitter Universe

abstract:
  The process of fermion production in the field of a magnetic dipole on a de
Sitter expanding universe is analyzed. The amplitude and probability for
production of massive fermions are obtained using the exact solution of the
Dirac equation written in the momentum-helicity basis. We found that the most
probable transitions are those that generate the fermion pair perpendicular to
the direction of the magnetic field. The behavior of the probability is
graphically studied for large/small values of the expansion factor, and a
detailed analysis of the probability in terms of the angle between the momenta
vectors of the particle and antiparticle is performed. The phenomenon of
fermion production is significant only at large expansion which corresponds to
the conditions from the early Universe. When the expansion factor vanishes we
recover the Minkowski limit where this process is forbidden by the simultaneous
energy-momentum conservation.


title: Symplectic Parabolicity and L^2 Symplectic Harmonic Forms

abstract:
  In this paper, we study the symplectic cohomologies and symplectic harmonic
forms which introduced by Tseng and Yau. Based on this, we get if
$(M^{2n},\omega)$ is a compact symplectic parabolic manifold which satisfies
the hard Lefschetz property, then its Euler number satisfies the inequality
$(-1)^n\chi(M)\geq 0$.


title:
Number-resolved master equation approach to quantum measurement and
  quantum transport

abstract:
  In addition to the well-known Landauer-Buttiker scattering theory and the
nonequilibrium Green's function technique for mesoscopic transports, an
alternative (and very useful) scheme is quantum master equation approach. In
this article, we review the particle-number (n)-resolved master equation (n-ME)
approach and its systematic applications in quantum measurement and quantum
transport problems. The n-ME contains rich dynamical information, allowing
efficient study of topics such as shot noise and full counting statistics
analysis. Moreover, we also review a newly developed master equation approach
(and its n-resolved version) under self-consistent Born approximation. The
application potential of this new approach is critically examined via its
ability to recover the exact results for noninteracting systems under arbitrary
voltage and in presence of strong quantum interference, and the challenging
non-equilibrium Kondo effect.


title:
Anomalous thermal decoherence in a quantum magnet measured with neutron
  spin-echo spectroscopy

abstract:
  The effect of temperature dependent asymmetric line broadening is
investigated in Cu(NO$_3$)$_2\cdot$2.5D$_2$O, a model material for a 1-D bond
alternating Heisenberg chain, using the high resolution neutron-resonance
spin-echo (NRSE) technique. Inelastic neutron scattering experiments on
dispersive excitations including phase sensitive measurements demonstrate the
potential of NRSE to resolve line shapes, which are non-Lorentzian, opening up
a new and hitherto unexplored class of experiments for the NRSE method beyond
standard line width measurements. The particular advantage of NRSE is its
direct access to the correlations in the time domain without convolution with
the resolution function of the background spectrometer. This novel application
of NRSE is very promising and establishes a basis for further experiments on
different systems, since the results for Cu(NO$_3$)$_2\cdot$2.5D$_2$O are
applicable to a broad range of quantum systems.


title: Gamma-Ray Astronomy from the Ground

abstract:
  The observation of cosmic gamma-rays from the ground is based upon the
detection of gamma-ray initiated air showers. At energies between approximately
$10^{11}$ eV and $10^{13}$ eV, the imaging air Cherenkov technique is a
particularly successful approach to observe gamma-ray sources with energy
fluxes as low as $\approx 10^{-13}$ erg\,cm$^{-2}\,$s$^{-1}$. The observations
of gamma-rays in this energy band probe particle acceleration in astrophysical
plasma conditions and are sensitive to high energy phenomena beyond the
standard model of particle physics (e.g., self-annihilating or decaying dark
matter, violation of Lorentz invariance, mixing of photons with light
pseudo-scalars). The current standing of the field and its major instruments
are summarised briefly by presenting selected highlights. A new generation of
ground based gamma-ray instruments is currently under development. The
perspectives and opportunities of these future facilities will be discussed.


title: Multimodal Emotion Recognition Using Multimodal Deep Learning

abstract:
  To enhance the performance of affective models and reduce the cost of
acquiring physiological signals for real-world applications, we adopt
multimodal deep learning approach to construct affective models from multiple
physiological signals. For unimodal enhancement task, we indicate that the best
recognition accuracy of 82.11% on SEED dataset is achieved with shared
representations generated by Deep AutoEncoder (DAE) model. For multimodal
facilitation tasks, we demonstrate that the Bimodal Deep AutoEncoder (BDAE)
achieves the mean accuracies of 91.01% and 83.25% on SEED and DEAP datasets,
respectively, which are much superior to the state-of-the-art approaches. For
cross-modal learning task, our experimental results demonstrate that the mean
accuracy of 66.34% is achieved on SEED dataset through shared representations
generated by EEG-based DAE as training samples and shared representations
generated by eye-based DAE as testing sample, and vice versa.


title:
Uniform convergence of V-cycle multigrid algorithms for two-dimensional
  fractional Feynman-Kac equation

abstract:
  In this paper we derive new uniform convergence estimates for the V-cycle MGM
applied to symmetric positive definite Toeplitz block tridiagonal matrices, by
also discussing few connections with previous results. More concretely, the
contributions of this paper are as follows: (1) It tackles the Toeplitz systems
directly for the elliptic PDEs. (2) Simple (traditional) restriction operator
and prolongation operator are employed in order to handle general Toeplitz
systems at each level of the recursion. Such a technique is then applied to
systems of algebraic equations generated by the difference scheme of the
two-dimensional fractional Feynman-Kac equation, which describes the joint
probability density function of non-Brownian motion. In particular, we consider
the two coarsening strategies, i.e., doubling the mesh size (geometric MGM) and
Galerkin approach (algebraic MGM), which lead to the distinct coarsening
stiffness matrices in the general case: however, several numerical experiments
show that the two algorithms produce almost the same error behaviour.


title:
Broad-band properties of flat-spectrum radio-loud narrow-line Seyfert 1
  galaxies

abstract:
  We report about recent updates of broad-band properties of radio-loud
narrow-line Seyfert 1 galaxies.


title:
A generalized architecture of quantum secure direct communication for N
  disjointed users with authentication

abstract:
  In this paper, we generalize a secured direct communication process between N
users with partial and full cooperation of quantum server. The security
analysis of authentication and communication processes against many types of
attacks proved that the attacker cannot gain any information during
intercepting either authentication or communication processes. Hence, the
security of transmitted message among N users is ensured as the attacker
introduces an error probability irrespective of the sequence of measurement.


title: An Outer Arm in the Second Galactic Quadrant: Structure

abstract:
  The lack of arm tracers, especially the remote tracers, is one of the most
difficult problems preventing us from studying the structure of the Milky Way.
Fortunately, with its high-sensitivity CO survey, the Milky Way Imaging Scroll
Painting (MWISP) project offers such an opportunity. Since completing about
one-third of its mission, an area of l=[100,150] deg, b=[-3,5] deg has nearly
been covered. The Outer arm of the Milky Way first clearly revealed its shape
in the second galactic quadrant in the form of molecular gas --- this is the
first time that the Outer arm has been reported in such a large-scale mapping
of molecular gas. Using the 115 GHz 12CO(1-0) data of MWISP at the LSR velocity
~= [-100,-60] km s^-1 and in the area mentioned above, we have detected 481
molecular clouds in total, and among them 332 (about 69\%) are newly detected
and 457 probably belong to the Outer arm. The total mass of the detected Outer
arm clouds is ~ 3.1*10^6 M_sun. Assuming that the spiral arm is a logarithmic
spiral, the pitch angle is fitted as ~ 13.1 deg. Besides combining both the CO
data from MWISP and the 21 cm HI data from the Canadian Galactic Plane Survey
(CGPS), the gas distribution, warp, and thickness of the Outer arm are also
studied.


title:
Stable Marriage with Covering Constraints: A Complete Computational
  Trichotomy

abstract:
  We consider Stable Marriage with Covering Constraints (SMC): in this variant
of Stable Marriage, we distinguish a subset of women as well as a subset of
men, and we seek a matching with fewest number of blocking pairs that matches
all of the distinguished people. We investigate how a set of natural
parameters, namely the maximum length of preference lists for men and women,
the number of distinguished men and women, and the number of blocking pairs
allowed determine the computational tractability of this problem. Our main
result is a complete complexity trichotomy that, for each choice of the studied
parameters, classifies SMC as polynomial-time solvable, NP-hard and
fixed-parameter tractable, or NP-hard and W[1]-hard. We also classify all cases
of one-sided constraints where only women may be distinguished.


title:
Holomorphic projection for $\mathop{Sp}_2(\mathbb R)$ -- the case of
  weight $(4,4)$

abstract:
  We define non-holomorphic Poincar\'e series of exponential type for
symplectic groups $\mathop{Sp}_m(\mathbb R)$ and continue them analytically in
case $m=2$ for the small weight $(4,4)$. For this we construct certain Casimir
operators and study the spectral properties of their resolvents on
$L^2(\Gamma\backslash \mathop{Sp}_2(\mathbb R))$. Using the holomorphically
continued Poincar\'e series, the holomorphic projection is described in terms
of Fourier coefficients using Sturm's operator.


title: Cell-Free Massive MIMO versus Small Cells

abstract:
  A Cell-Free Massive MIMO (multiple-input multiple-output) system comprises a
very large number of distributed access points (APs)which simultaneously serve
a much smaller number of users over the same time/frequency resources based on
directly measured channel characteristics. The APs and users have only one
antenna each. The APs acquire channel state information through time-division
duplex operation and the reception of uplink pilot signals transmitted by the
users. The APs perform multiplexing/de-multiplexing through conjugate
beamforming on the downlink and matched filtering on the uplink. Closed-form
expressions for individual user uplink and downlink throughputs lead to max-min
power control algorithms. Max-min power control ensures uniformly good service
throughout the area of coverage. A pilot assignment algorithm helps to mitigate
the effects of pilot contamination, but power control is far more important in
that regard.
  Cell-Free Massive MIMO has considerably improved performance with respect to
a conventional small-cell scheme, whereby each user is served by a dedicated
AP, in terms of both 95%-likely per-user throughput and immunity to shadow
fading spatial correlation. Under uncorrelated shadow fading conditions, the
cell-free scheme provides nearly 5-fold improvement in 95%-likely per-user
throughput over the small-cell scheme, and 10-fold improvement when shadow
fading is correlated.


title:
Generation of random deviates for relativistic quantum-statistical
  distributions

abstract:
  We provide an algorithm for generation of momenta (or energies) of
relativistic particles according to the relativistic Bose-Einstein or
Fermi-Dirac distributions. The algorithm uses rejection method with effectively
selected comparison function so that the acceptance rate of the generated
values is always better than 0.9. It might find its use in Monte-Carlo
generators of particles from reactions in high-energy physics.


title: Truncation of Haar random matrices in $\mathrm{GL}_N(\mathbb{Z}_m)$

abstract:
  The asymptotic law of the truncated $S\times S$ random submatrix of a Haar
random matrix in $\mathrm{GL}_N(\mathbb{Z}_m)$ as $N$ goes to infinity is
obtained. The same result is also obtained when $\mathbb{Z}_m$ is replaced by
any commutative compact local ring whose maximal ideal is topologically closed.


title: A Stein deficit for the logarithmic Sobolev inequality

abstract:
  We provide explicit lower bounds for the deficit in the Gaussian logarithmic
Sobolev inequality in terms of differential operators that are naturally
associated with the so-called Stein characterization of the Gaussian
distribution. The techniques are based on a crucial use of the representation
of the relative Fisher information, along the Ornstein-Uhlenbeck semigroup, in
terms of the Minimal Mean-Square Error from information theory.


title: Diophantine triples with values in $k$-generalized Fibonacci sequences

abstract:
  We show that if $k\ge 2$ is an integer and $(F_n^{(k)})_{n\ge 0}$ is the
sequence of $k$-generalized Fibonacci numbers, then there are only finitely
many triples of positive integers $1<a<b<c$ such that $ab+1,~ac+1,~bc+1$ are
all members of $\{F_n^{(k)}: n\ge 1\}$. This generalizes a previous result (cf.
arXiv:1508.07760) where the statement for $k=3$ was proved. The result is
ineffective since it is based on Schmidt's subspace theorem.


title: Machine Agency in Human-Machine Networks; Impacts and Trust Implications

abstract:
  We live in an emerging hyper-connected era in which people are in contact and
interacting with an increasing number of other people and devices.
Increasingly, modern IT systems form networks of humans and machines that
interact with one another. As machines take a more active role in such
networks, they exert an in-creasing level of influence on other participants.
We review the existing literature on agency and propose a definition of agency
that is practical for describing the capabilities and impact human and machine
actors may have in a human-machine network. On this basis, we discuss and
demonstrate the impact and trust implica-tions for machine actors in
human-machine networks for emergency decision support, healthcare and future
smart homes. We maintain that machine agency not only facilitates human to
machine trust, but also interpersonal trust; and that trust must develop to be
able to seize the full potential of future technology.


title:
Three Theorems on odd degree Chebyshev polynomials and more generalized
  permutation polynomials over a ring of module $2^w$

abstract:
  Odd degree Chebyshev polynomials over a ring of modulo $2^w$ have two kinds
of period. One is an "orbital period". Odd degree Chebyshev polynomials are
bijection over the ring. Therefore, when an odd degree Chebyshev polynomial
iterate affecting a factor of the ring, we can observe an orbit over the ring.
The "orbital period" is a period of the orbit. The other is a "degree period".
It is observed when changing the degree of Chebyshev polynomials with a fixed
argument of polynomials. Both kinds of period have not been completely studied.
In this paper, we clarify completely both of them. The knowledge about them
enables us to efficiently solve degree decision problem of Chebyshev polynomial
over the ring, and so a key-exchange protocol with Chebyshev polynomial over
the ring is not secure. In addition, we generalize the discussion and show that
a key-exchange protocol with more generalized permutation polynomials which
belong to a certain class is not secure.


title: Criticality and Energy Landscapes in Spin Glasses

abstract:
  Despite the extreme simplicity in their definition, spin glasses disclose a
wide variety of non-trivial behaviors that are not yet fully understood. In
this thesis we try to shed light on some of them, focusing on one hand on the
search of phase transitions under perturbations of the Hamiltonian, and on the
other hand on the zero-temperature properties and responses to external
stimuli. After introducing spin glasses through a historiographical review, and
useful concepts on phase transitions and numerics, the results of two massive
Monte Carlo campaigns on three-dimensional systems are shown. In the first one
the de Almeida-Thouless transition is studied, and a new finite-size scaling
ansatz is proposed, that accelerates the convergence to the thermodynamic
limit. In the second one the phase diagram of the Heisenberg spin glass with
random exchange anisotropy is reconstructed. In the following part of the
manuscript, surprising features of zero-temperature statics and dynamics of
several spin glass models are found. Among them, correlations between soft
spins that arise spontaneously during avalanches, and the discovery of
localized states that involve the presence of two-level systems.


title:
Minimizing movements along a sequence of functionals and curves of
  maximal slope

abstract:
  We prove that a general condition introduced by Colombo and Gobbino to study
limits of curves of maximal slope allows also to characterize minimizing
movements along a sequence of functionals as curves of maximal slope of a limit
functional.


title:
Maximal functions associated with nonisotropic dilations of hypersufaces
  in R^3

abstract:
  The goal of this article is to establish L^p-estimates for maximal functions
associated with nonisotropic dilations of hypersurfaces in R^3. Several results
have already been obtained by Greenleaf, Iosevich-Sawyer-Seeger,
Ikromov-Kempe-Mueller and Zimmermann, but for some situations such as the
hypersurface parameterized as the graph of a smooth function
$\Phi(x_1,x_2)=x_2^d(1+\mathcal{O}(x_2^m))$ near the origin, where $d\geq 2$,
$m\geq 1$, and associated dilations $\delta_t(x)=(t^ax_1,tx_2,t^dx_3)$ for an
arbitrary real number a>0, the question was open until recently. In fact, such
problems do arise already in lower dimensions. For instance, we consider the
curve $\gamma(x)=(x,x^2(1+\phi(x)))$ and associated dilations
$\delta_t(x)=(tx_1,t^2x_2)$. If $\phi\equiv 0$, then the corresponding maximal
function is the maximal function along parabolas in the plane, which is very
well understood due to the work by Nagel-Riviere-Wainger and others. If
$\phi\neq 0$ and $\phi(x)=\mathcal{O}(x^m)$, $m\geq 1$, the problem was open
until recently, however, the corresponding maximal function shows features
related to the Bourgain circular maximal function, which required deep ideas
and local smoothing estimates established by Mockenhaupt-Seeger-Sogge for
Fourier integral operators satisfying the so-called "cinematic curvature"
condition. However, we observe that in the study of M related to the mentioned
curve $\gamma(x)$ and associated dilations, we will consider a family of
corresponding Fourier integral operators which fail to satisfy the "cinematic
curvature condition" uniformly, which means that classical local smoothing
estimates could not be directly applied to our problem. In this article, we
develop new ideas in order to overcome the above difficulty and finally
establish sharp L^p-estimates for the maximal function related to the curve
$\gamma(x)$ ......


title:
Topological entropy of sets of generic points for actions of amenable
  groups

abstract:
  Let $G$ be a countable discrete amenable group which acts continuously on a
compact metric space $X$ and let $\mu$ be an ergodic $G-$invariant Borel
probability measure on $X$. For a fixed tempered F{\o}lner sequence $\{F_n\}$
in $G$ with $\lim\limits_{n\rightarrow+\infty}\frac{|F_n|}{\log n}=\infty$, we
prove the following variational principle:
$$h^B(G_{\mu},\{F_n\})=h_{\mu}(X,G),$$ where $G_{\mu}$ is the set of generic
points for $\mu$ with respect to $\{F_n\}$ and $h^B(G_{\mu},\{F_n\})$ is the
Bowen topological entropy (along $\{F_n\}$) on $G_{\mu}$. This generalizes the
classical result of Bowen in 1973.


title:
Weak topological insulators with step edges: Subband engineering and its
  effect on electron transport

abstract:
  A three-dimensional weak topological insulator (WTI) can be regarded as
stacked layers of two-dimensional quantum spin-Hall insulators, each of which
accommodates a one-dimensional helical edge mode. Massless Dirac electrons
emerge on a side surface of WTIs as a consequence of the hybridization of such
helical edge modes. We study the energy spectrum and transport of Dirac
electrons on a side surface in the presence of step edges, which significantly
modify the way of hybridization. It is shown that pseudo-helical modes with a
nearly gapless linear dispersion can be created by manipulating step edges in a
certain manner. We numerically calculate the average conductance of weakly
disordered WTIs and show that it is markedly enhanced by pseudo-helical modes.


title: Dephasing-Controlled Particle Transport Devices

abstract:
  We study the role of dephasing in transport through different structures. We
show that interference effects invalidate Kirchhoff's circuit laws in quantum
devices. We present circuits where the particle transport and the direction of
rectification can be controlled through the dephasing strength. This suggests
the possibility of constructing molecular devices with new functionalities
which use dephasing as a control parameter.


title: Sunquake Generation by Coronal Magnetic Restructuring

abstract:
  Sunquakes are the surface signatures of acoustic waves in the Sun's interior
that are produced by some but not all flares and coronal mass ejections (CMEs).
This paper explores a mechanism for sunquake generation by the magnetic field
changes that occur during flares and CMEs, using MHD simulations with a
semiempirical FAL-C atmosphere to demonstrate the generation of acoustic waves
in the interior in response to changing magnetic tilt in the corona. We find
that Alfven-sound resonance combined with the ponderomotive force produces
acoustic waves in the interior with sufficient energy to match sunquake
observations when the magnetic field angle changes by the order of 10 degrees
in a region where the coronal field strength is a few hundred gauss or more.
The most energetic sunquakes are produced when the coronal field is strong,
while the variation of magnetic field strength with height and the time scale
of the tilt change are of secondary importance.


title: The comb representation of compact ultrametric spaces

abstract:
  We call a \emph{comb} a map $f:I\to [0,\infty)$, where $I$ is a compact
interval, such that $\{f\ge \varepsilon\}$ is finite for any $\varepsilon$. A
comb induces a (pseudo)-distance $\dtf$ on $\{f=0\}$ defined by $\dtf(s,t) =
\max_{(s\wedge t, s\vee t)} f$. We describe the completion $\bar I$ of
$\{f=0\}$ for this metric, which is a compact ultrametric space called
\emph{comb metric space}.
  Conversely, we prove that any compact, ultrametric space $(U,d)$ without
isolated points is isometric to a comb metric space. We show various examples
of the comb representation of well-known ultrametric spaces: the Kingman
coalescent, infinite sequences of a finite alphabet, the $p$-adic field and
spheres of locally compact real trees. In particular, for a rooted, locally
compact real tree defined from its contour process $h$, the comb isometric to
the sphere of radius $T$ centered at the root can be extracted from $h$ as the
depths of its excursions away from $T$.


title: Permutahedral Structures of $E_2$ Operads

abstract:
  There are basically two interesting breeds of $E_2$ operads, those that
detect loop spaces and those that solve Deligne's conjecture. The former
deformation retract to Milgram's space obtained by gluing together permutahedra
at their faces. We show how the second breed can be covered by permutahedra as
well. Even more is true, the quotient is actually already an operad up to
homotopy, which induces the operad structure on cellular chains adapted to
prove Deligne's conjecture, while no such structure is known on Milgram's
space. We show, explicitely, that these two quotients are homotopy equivalent.
This gives a new topological proof that operads of this type are indeed of the
right homotopy type. It also furnishes a very nice clean description in terms
of polyhedra, and with it PL topology, for the whole story. The permutahedra
and partial orders play a central role. This, in turn, provides direct links to
other fields of mathematics. We for instance find a new cellular decomposition
of permutahedra using partial orders and that the permutahedra give the cells
for the Dyer--Lashof operations.


title: Can Economics Afford Not To Become Natural Science?

abstract:
  The 'Discussion & Debate' issue of this Euro. Phys. J. Special Topic volume
is: 'Can economics be a Physical Science?' I would rather address a more
general question: 'Can economics or sociology avoid joining Natural Science?'
and argue that mainstream or core economics or sociology can not escape joining
natural science.


title: Random numbers from vacuum fluctuations

abstract:
  We implement a quantum random number generator based on a balanced homodyne
measurement of vacuum fluctuations of the electromagnetic field. The digitized
signal is directly processed with a fast randomness extraction scheme based on
a linear feedback shift register. The random bit stream is continuously read in
a computer at a rate of about 480 Mbit/s and passes an extended test suite for
random numbers.


title: The Independent Domination Polynomial

abstract:
  A vertex subset $W\subseteq V$ of the graph $G=(V,E)$ is an independent
dominating set if every vertex in $V\backslash W$ is adjacent to at least one
vertex in $W$ and the vertices of $W$ are pairwise non-adjacent. The
independent domination polynomial is the ordinary generating function for the
number of independent dominating sets in the graph. We investigate in this
paper properties of the independent domination polynomial and some interesting
connections to well known counting problems.


title: Collapse of Langmuir solitons in inhomogeneous plasmas

abstract:
  Propagation of Langmuir solitons in inhomogeneous plasmas is investigated
numerically. Through numerical simulation solving Zakharov equations, the
solitons are accelerated toward the low density side. As a consequence,
isolated cavities moving at ion sound velocities are emitted. When the
acceleration is further increased, solitons collapse and the cavities separate
into two lumps released at ion sound velocities. The threshold is estimated by
an analogy between the soliton and a particle overcoming the self-generated
potential well.


title:
Coflow turbulence of superfluid ${}^4$He in a square channel: Vortices
  trapped on a cylindrical attractor

abstract:
  We perform a numerical simulation of the dynamics of quantized vortices
produced by coflow in a square channel using the vortex filament model. Unlike
the situation in thermal counterflow, where the superfluid velocity $v_{\rm s}$
and normal-fluid velocity $v_{\rm n}$ flow in opposite directions, in coflow,
$v_{\rm s}$ and $v_{\rm n}$ flow in the same direction. Quantum turbulence in
thermal counterflow has been long studied theoretically and experimentally, and
its various features have been revealed.In recent years, an experiment on
quantum turbulence in coflow has been performed to observe different features
of thermal counterflow. By supposing that $v_{\rm s}$ is uniform and $v_{\rm
n}$ takes the Hagen-Poiseuille profile, which is different from the experiment
where $v_{\rm n}$ is thought to be turbulent, we calculate the coflow
turbulence. Vortices preferentially accumulate on the surface of a cylinder for
$v_{\rm s} \simeq v_{\rm n}$ by mutual friction; namely, the coflow turbulence
has an attractor. How strongly the vortices are attracted depends on the
temperature and velocity. The length of the vortices increases as the vortices
protruding from the cylindrical attractor continue to wrap around it. As the
vortices become dense on the attractor, they spread toward its interior by
their repulsive interaction. Then, the superfluid velocity profile induced by
the vortices gradually mimics the normal-fluid velocity profile. This is an
indication of velocity matching, which is an important feature of coflow
turbulence.


title: N-Quasi-Abelian Categories vs N-Tilting Torsion Pairs

abstract:
  It is a well established fact that the notions of quasi-abelian categories
and tilting torsion pairs are equivalent. This equivalence fits in a wider
picture including tilting pairs of $t$-structures.
  Firstly, we extend this picture into a hierarchy of $n$-quasi-abelian
categories and $n$-tilting torsion classes. We prove that any $n$-quasi-abelian
category admits a derived category endowed with a $n$-tilting pair of
$t$-structures such that the respective hearts are derived equivalent.
  Secondly, we describe the hearts of these $t$-structures as quotient
categories of coherent functors, generalizing Auslander's Formula.
  Thirdly, we apply our results to Bridgeland's theory of perverse coherent
sheaves for flop contractions. In Bridgeland's work, the relative dimension $1$
assumption guaranteed that $f_*$-acyclic coherent sheaves form a $1$-tilting
torsion class, whose associated heart is derived equivalent to $D(Y)$. We
generalize this theorem to relative dimension $2$.


title: Theoretical Analysis of the $k$-Means Algorithm - A Survey

abstract:
  The $k$-means algorithm is one of the most widely used clustering heuristics.
Despite its simplicity, analyzing its running time and quality of approximation
is surprisingly difficult and can lead to deep insights that can be used to
improve the algorithm. In this paper we survey the recent results in this
direction as well as several extension of the basic $k$-means method.


title: Cache-enabled Heterogeneous Cellular Networks: Comparison and Tradeoffs

abstract:
  Caching popular contents at base stations (BSs) is a promising way to unleash
the potential of cellular heterogeneous networks (HetNets), where backhaul has
become a bottleneck. In this paper, we compare a cache-enabled HetNet where a
tier of multi-antenna macro BSs is overlaid by a tier of helper nodes having
caches but no backhaul with a conventional HetNet where the macro BSs tier is
overlaid by a tier of pico BSs with limited-capacity backhaul. We resort
stochastic geometry theory to derive the area spectral efficiencies (ASEs) of
these two kinds of HetNets and obtain the closed-form expressions under a
special case. We use numerical results to show that the helper density is only
1/4 of the pico BS density to achieve the same target ASE, and the helper
density can be further reduced by increasing cache capacity. With given total
cache capacity within an area, there exists an optimal helper node density that
maximizes the ASE.


title:
Interference Evidence for Rashba-Type Spin-Split on Semimetallic WTe2
  Surface

abstract:
  Semimetallic tungsten ditelluride (WTe2) displays an extremely large
non-saturating magnetoresistance (XMR), which is the subject of intense
interest. This phenomenon is thought to arise from the combination of perfect
n-p charge compensation with low carrier densities in WTe2 and presumably
details of its band structure. Recently, "spin texture" induced by strong
spin-orbital coupling (SOC) has been observed in WTe2 by angle-resolved
photoemission spectroscopy (ARPES). This provides a mechanism for protecting
backscattering for the states involved and thus was proposed to play an
important role in the XMR of WTe2. Here, based on our density functional
calculations for bulk WTe2, we found a strong Rashba spin-orbit effect in the
calculated band structure due to its non-centrosymmetric structure. This splits
bands and two-fold spin degeneracy of bands is lifted. A prominent Umklapp
interference pattern (a spectroscopic feature with involving reciprocal lattice
vectors) can be observed by scanning tunneling microscopic (STM) measurements
on WTe2 surface at 4.2 K. This differs distinctly from the surface atomic
structure demonstrated at 77 K. The energy dependence of Umklapp interference
shows a strong correspondence with densities of states integrated from ARPES
measurement, manifesting a fact that the bands are spin-split on the opposites
side of Gamma point. Spectroscopic survey reveals the ratio of electron/hole
asymmetry changes alternately with lateral locations along b axis, providing a
microscopic picture for double-carrier transport of semimetallic WTe2. The
calculated band structure and Fermi surface is further supported by our ARPES
results and Shubnikov-de Haas (SdH) oscillations measurements.


title:
Eigenfunction structure and scaling of two interacting particles in the
  one-dimensional Anderson model

abstract:
  The localization properties of eigenfunctions for two interacting particles
in the one-dimensional Anderson model are studied for system sizes up to
$N=5000$ sites corresponding to a Hilbert space of dimension $\approx 10^7$
using the Green function Arnoldi method. The eigenfunction structure is
illustrated in position, momentum and energy representation, the latter
corresponding to an expansion in non-interacting product eigenfunctions.
Different types of localization lengths are computed for parameter ranges in
system size, disorder and interaction strengths inaccessible until now. We
confirm that one-parameter scaling theory can be successfully applied provided
that the condition of $N$ being significantly larger than the one-particle
localization length $L_1$ is verified. The enhancement effect of the
two-particle localization length $L_2$ behaving as $L_2\sim L_1^2$ is clearly
confirmed for a certain quite large interval of optimal interactions strengths.
Further new results for the interaction dependence in a very large interval, an
energy value outside the band center, and different interaction ranges are
obtained.


title:
Modified Profile Likelihood Inference and Interval Forecast of the Burst
  of Financial Bubbles

abstract:
  We present a detailed methodological study of the application of the modified
profile likelihood method for the calibration of nonlinear financial models
characterised by a large number of parameters. We apply the general approach to
the Log-Periodic Power Law Singularity (LPPLS) model of financial bubbles. This
model is particularly relevant because one of its parameters, the critical time
$t_c$ signalling the burst of the bubble, is arguably the target of choice for
dynamical risk management. However, previous calibrations of the LPPLS model
have shown that the estimation of $t_c$ is in general quite unstable. Here, we
provide a rigorous likelihood inference approach to determine $t_c$, which
takes into account the impact of the other nonlinear (so-called "nuisance")
parameters for the correct adjustment of the uncertainty on $t_c$. This
provides a rigorous interval estimation for the critical time, rather than a
point estimation in previous approaches. As a bonus, the interval estimations
can also be obtained for the nuisance parameters ($m,\omega$, damping), which
can be used to improve filtering of the calibration results. We show that the
use of the modified profile likelihood method dramatically reduces the number
of local extrema by constructing much simpler smoother log-likelihood
landscapes. The remaining distinct solutions can be interpreted as genuine
scenarios that unfold as the time of the analysis flows, which can be compared
directly via their likelihood ratio. Finally, we develop a multi-scale profile
likelihood analysis to visualize the structure of the financial data at
different scales (typically from 100 to 750 days). We test the methodology
successfully on synthetic price time series and on three well-known historical
financial bubbles.


title:
Derivation of limit equation for a perturbed 3D periodic Boussinesq
  system

abstract:
  We consider a system describing the long-time dynamics of an hydrodynamical,
density-dependent flow under the effects of gravitational forces. We prove that
if the Froude number is sufficiently small such system is globally well posed
with respect to a $ H^s, \ s>1/2 $ Sobolev regularity. Moreover if the Froude
number converges to zero we prove that the solutions of the aforementioned
system converge (strongly) to a stratified three-dimensional Navier-Stokes
system. No smallness assumption is assumed on the initial data.