title: Visual Place Recognition with Probabilistic Vertex Voting

abstract:
  We propose a novel scoring concept for visual place recognition based on
nearest neighbor descriptor voting and demonstrate how the algorithm naturally
emerges from the problem formulation. Based on the observation that the number
of votes for matching places can be evaluated using a binomial distribution
model, loop closures can be detected with high precision. By casting the
problem into a probabilistic framework, we not only remove the need for
commonly employed heuristic parameters but also provide a powerful score to
classify matching and non-matching places. We present methods for both a 2D-2D
pose-graph vertex matching and a 2D-3D landmark matching based on the above
scoring. The approach maintains accuracy while being efficient enough for
online application through the use of compact (low dimensional) descriptors and
fast nearest neighbor retrieval techniques. The proposed methods are evaluated
on several challenging datasets in varied environments, showing
state-of-the-art results with high precision and high recall.


title:
On the viscosity solutions to a class of nonlinear degenerate parabolic
  differential equations

abstract:
  In this work, we show existence and uniqueness of positive solutions of
$H(Du, D^2u)+\chi(t)|Du|^\Gamma-f(u)u_t=$ in $\Omega\times(0, T)$ and $u=h$ on
its parabolic boundary. The operator $H$ satisfies certain homogeneity
conditions, $\Gamma>0$ and depends on the degree of homogeneity of $H$, $f>0$,
increasing and meets a concavity condition. We also consider the case $f\equiv
1$ and prove existence of solutions without sign restrictions.


title:
A population of planetary systems characterized by short-period,
  Earth-sized planets

abstract:
  We analyze data from the Quarter 1-17 Data Release 24 (Q1--Q17 DR24) planet
candidate catalog from NASA's Kepler mission, specifically comparing systems
with single transiting planets to systems with multiple transiting planets, and
identify a distinct population of exoplanets with a necessarily distinct system
architecture. Such an architecture likely indicates a different branch in their
evolutionary past relative to the typical Kepler system. The key feature of
these planetary systems is an isolated, Earth-sized planet with a roughly
one-day orbital period. We estimate that at least 24 of the 144 systems we
examined (>~17%) are members of this population. Accounting for detection
efficiency, such planetary systems occur with a frequency similar to the hot
Jupiters.


title:
The SCUBA-2 Cosmology Legacy Survey: The EGS deep field I - Deep number
  counts and the redshift distribution of the recovered Cosmic Infrared
  Background at 450 and 850 um

abstract:
  We present deep observations at 450 um and 850 um in the Extended Groth Strip
field taken with the SCUBA-2 camera mounted on the James Clerk Maxwell
Telescope as part of the deep SCUBA-2 Cosmology Legacy Survey (S2CLS),
achieving a central instrumental depth of $\sigma_{450}=1.2$ mJy/beam and
$\sigma_{850}=0.2$ mJy/beam. We detect 57 sources at 450 um and 90 at 850 um
with S/N > 3.5 over ~70 sq. arcmin. From these detections we derive the number
counts at flux densities $S_{450}>4.0$ mJy and $S_{850}>0.9$ mJy, which
represent the deepest number counts at these wavelengths derived using directly
extracted sources from only blank-field observations with a single-dish
telescope. Our measurements smoothly connect the gap between previous shallower
blank-field single-dish observations and deep interferometric ALMA results. We
estimate the contribution of our SCUBA-2 detected galaxies to the cosmic
infrared background (CIB), as well as the contribution of 24 um-selected
galaxies through a stacking technique, which add a total of $0.26\pm0.03$ and
$0.07\pm0.01$ MJy/sr, at 450 um and 850 um, respectively. These surface
brightnesses correspond to $60\pm20$ and $50\pm20$ per cent of the total CIB
measurements, where the errors are dominated by those of the total CIB. Using
the photometric redshifts of the 24 um-selected sample and the redshift
distributions of the submillimetre galaxies, we find that the redshift
distribution of the recovered CIB is different at each wavelength, with a peak
at $z\sim1$ for 450 um and at $z\sim2$ for 850um, consistent with previous
observations and theoretical models.


title: Unlikely Intersections in Finite Characteristic

abstract:
  We present a heuristic argument based on Honda-Tate theory against many
conjectures in `unlikely intersections' over the algebraic closure of a finite
field; notably, we conjecture that every abelian variety of dimension 4 is
isogenous to a Jacobian. Using methods of additive combinatorics, we are able
to give a negative answer to a related question of Chai and Oort where the
ambient Shimura Variety is a power of the modular curve.


title: Long Term Sunspot Cycle Phase Coherence with Periodic Phase Disruptions

abstract:
  In 1965 Paul D. Jose published his discovery that both the motion of the Sun
about the center of mass of the solar system and periods comprised of eight
Hale magnetic sunspot cycles with a mean period of ~22.37 years have a matching
periodicity of ~179 years. We have investigated the implied link between solar
barycentric torque cycles and sunspot cycles and have found that the unsigned
solar torque values from 1610 to 2057 are consistently phase and magnitude
coherent in ~179 year Jose Cycles. We are able to show that there is also a
surprisingly high degree of sunspot cycle phase coherence for times of minima
in addition to magnitude correlation of peaks between the nine Schwabe sunspot
cycles of 1878.8 to 1976.1 (SC12 through SC20) and those of 1699 to 1798.3
(SC[-5] through SC4). We further show that the remaining seven Schwabe cycles
in each ~179 year cycle are non-coherent. In addition we have analyzed the
empirical solar motion triggers of both sunspot cycle phase coherence and phase
disruption, from which we conclude that sunspot cycles SC28 through SC35 (2057
to 2143) will be phase coherent at times of minima and amplitude correlated at
maxima with SC12 through SC19 (1878.8-1964.8). The resulting predicted start
times +/- 0.9 year, 1 sigma, of future sunspot cycles SC28 to SC36 are
tabulated.


title: Review of Inferring Latent Attributes from Twitter

abstract:
  This paper reviews literature from 2011 to 2013 on how Latent attributes like
gender, political leaning etc. can be inferred from a person's twitter and
neighborhood data. Prediction of demographic data can bring value to
businesses, can prove instrumental in legal investigation. Moreover, political
leanings can be inferred from the wide variety of user data available on-line.
The motive of this review is to understand how large data sets can be made from
available twitter data. The tweeting and re tweeting behavior of a user can be
user to infer attributes like, gender, age etc. We explore in this text how
this field can be expanded in future and possible avenues for future research.


title:
Monotone Empirical Bayes Estimators for the Reproduction Number in
  Borel-Tanner Distribution

abstract:
  A monotone version of an empirical Bayes estimator for the parameter of the
Borel-Tanner distribution is constructed. Some properties of the estimator's
regret risk are illustrated through simulations.


title:
Hybrid quantum gate and entanglement between a "stationary" photonic
  qubit and a flying optical state via a giant cross Kerr nonlinear effect

abstract:
  Quantum information processing with hybrid protocols making use of discrete-
and continuous-variable currently attracts of great interest because of its
promising applications in scalable quantum computer and distant quantum
network. By inducing a giant cross-Kerr nonlinearity between two cavities, we
propose a general protocol for hybrid quantum gate and quantum entanglement
with high fidelity between a stationary, discrete photonic qubit and a flying
photonic state. Interestingly, our protocol can be used to conduct a
controlled-Z quantum gate between a stationary microwave photon stored in a
slowly-decaying microwave cavity and a flying optical photon, and therefore
enable to build quantum network for distant superconducting quantum circuits.


title: Learning Feedback Terms for Reactive Planning and Control

abstract:
  With the advancement of robotics, machine learning, and machine perception,
increasingly more robots will enter human environments to assist with daily
tasks. However, dynamically-changing human environments requires reactive
motion plans. Reactivity can be accomplished through replanning, e.g.
model-predictive control, or through a reactive feedback policy that modifies
on-going behavior in response to sensory events. In this paper, we investigate
how to use machine learning to add reactivity to a previously learned nominal
skilled behavior. We approach this by learning a reactive modification term for
movement plans represented by nonlinear differential equations. In particular,
we use dynamic movement primitives (DMPs) to represent a skill and a neural
network to learn a reactive policy from human demonstrations. We use the well
explored domain of obstacle avoidance for robot manipulation as a test bed. Our
approach demonstrates how a neural network can be combined with physical
insights to ensure robust behavior across different obstacle settings and
movement durations. Evaluations on an anthropomorphic robotic system
demonstrate the effectiveness of our work.


title: Highly tuneable hole quantum dots in Ge-Si core-shell nanowires

abstract:
  We define single quantum dots of lengths varying from 60 nm up to nearly half
a micron in Ge-Si core-shell nanowires. The charging energies scale inversely
with the quantum dot length between 18 and 4 meV. Subsequently, we split up a
long dot into a double quantum dot with a separate control over the tunnel
couplings and the electrochemical potential of each dot. Both single and double
quantum dot configurations prove to be very stable and show excellent control
over the electrostatic environment of the dots, making this system a highly
versatile platform for spin-based quantum computing.


title:
Nonperturbative solution of scalar Yukawa model in two- and three-body
  Fock space truncations

abstract:
  The Light-Front Tamm-Dancoff method of finding the nonperturbative solutions
in field theory is based on the Fock decomposition of the state vector,
complemented with the sector-dependent nonperturbative renormalization scheme.
We show in detail how to implement the renormalization procedure and to solve
the simplest nontrivial example of the scalar Yukawa model in the two- and
three-body Fock space truncations incorporating scalar "nucleon" and one or two
scalar "pions".


title: Surface Forces on a Deforming Ellipsoid in Shear Flow

abstract:
  We present a model for computing the surface force density on a fluid
ellipsoid in simple shear flow, which we derive by coupling existing models for
the shape of a fluid droplet and the surface force density on a solid
ellipsoid. The primary contribution of this coupling is to develop a method to
compute the force acting against a plane intersecting the ellipsoid, which we
call the fragmentation force. The model can be used to simulate the motion,
shape, surface force density, and breakage of fluid droplets and colloidal
aggregates in shear flow.


title: Local study of stable module categories via tensor triangulated geometry

abstract:
  We investigate the particular properties of the stable category of modules
over a finite dimensional cocommutative graded connected Hopf algebra $A$, via
tensor-triangulated geometry. This study requires some mild conditions on the
Hopf algebra $A$ under consideration (satisfied for example by all finite
sub-Hopf-algebras of the modulo $2$ Steenrod algebra). In particular, we study
some particular covers of its spectrum of prime ideals $\mathrm{Spc}(A)$, which
are related to Margolis' Work.
  We then exploit the existence of Margolis' Postnikov towers in this situation
to show that the localization at an open subset $U$ of $\mathrm{Spc}(A)$, for
various $U$, assembles in an $\infty$-stack.
  Finally, we turn to applications in the study of Picard groups of Hopf
algebras and localizations in the stable categories of modules.


title: Role of matter in extended quasidilaton massive gravity

abstract:
  The extended quasidilaton theory is one of the simplest Lorentz-invariant
massive gravity theories which can accommodate a stable self-accelerating
vacuum solution. In this paper we revisit this theory and study the effect of
matter fields. For a matter sector that couples minimally to the physical
metric, we find hints of a Jeans type instability in the IR. In the analogue
k-essence field set-up, this instability manifests itself as an IR ghost for
the scalar field perturbation, but this can be interpreted as a classical
instability that becomes relevant below some momentum scale in terms of matter
density perturbations. We also consider the effect of the background evolution
influenced by matter on the stability of the gravity sector perturbations. In
particular, we address the previous claims of ghost instability in the IR
around the late time attractor. We show that, although the matter-induced
modification of the evolution potentially brings tension to the stability
conditions, one goes beyond the regime of validity of the effective theory well
before the solutions become unstable. We also draw attention to the fact that
the IR stability conditions are also enforced by the existence requirements of
consistent background solutions.


title: Normal equivariant compactifications of G^2_a with Picard number one

abstract:
  We classify all normal G^2_a-surfaces with Picard number one, and
characterize which of these surfaces have at worst log canonical, and which
have at worst log terminal singularities, answering a question of Hassett and
Tschinkel (Int. Math. Res. Not., 1999). We also find all G^2_a-structures on
these surfaces and show that these surfaces and their minimal
desingularizations have the same G^2_a-structures (modulo equivalence of
G^2_a-actions). In particular, we show that some of these surfaces admit one
dimensional moduli of G^2_a-structures, answering another question of Hassett
and Tschinkel (Int. Math. Res. Not., 1999).


title: Fast Core Pricing for Rich Advertising Auctions

abstract:
  Standard ad auction formats do not immediately extend to settings where
multiple size configurations and layouts are available to advertisers. In these
settings, the sale of web advertising space increasingly resembles a
combinatorial auction with complementarities, where truthful auctions such as
the Vickrey-Clarke-Groves (VCG) can yield unacceptably low revenue. We
therefore study core selecting auctions, which boost revenue by setting
payments so that no group of agents, including the auctioneer, can jointly
improve their utilities by switching to a different outcome. Our main result is
a combinatorial algorithm that finds an approximate bidder optimal core point
with almost linear number of calls to the welfare maximization oracle. Our
algorithm is faster than previously-proposed heuristics in the literature and
has theoretical guarantees. We conclude that core pricing is implementable even
for very time sensitive practical use cases such as realtime auctions for
online advertising and can yield more revenue. We justify this claim
experimentally using the Microsoft Bing Ad Auction data, through which we show
our core pricing algorithm generates almost 26% more revenue than VCG on
average, about 9% more revenue than other core pricing rules known in the
literature, and almost matches the revenue of the standard Generalized Second
Price (GSP) auction.


title:
Precision requirements and innovative manufacturing for ultrahigh
  precision laser interferometry of gravitational-wave astronomy

abstract:
  With the LIGO announcement of the first direct detection of gravitational
waves (GWs), the GW Astronomy was formally ushered into our age. After
one-hundred years of theoretical investigation and fifty years of experimental
endeavor, this is a historical landmark not just for physics and astronomy, but
also for industry and manufacturing. The challenge and opportunity for industry
is precision and innovative manufacturing in large size - production of large
and homogeneous optical components, optical diagnosis of large components, high
reflectance dielectric coating on large mirrors, manufacturing of components
for ultrahigh vacuum of large volume, manufacturing of high attenuating
vibration isolation system, production of high-power high-stability
single-frequency lasers, production of high-resolution positioning systems etc.
In this talk, we address the requirements and methods to satisfy these
requirements. Optical diagnosis of large optical components requires large
phase-shifting interferometer; the 1.06 {\mu}m Phase Shifting Interferometer
for testing LIGO optics is an example. High quality mirrors are crucial for
laser interferometric GW detection, so as for ring laser gyroscope, high
precision laser stabilization via optical cavities, quantum optomechanics,
cavity quantum electrodynamics and vacuum birefringence measurement. There are
stringent requirements on the substrate materials and coating methods. For
cryogenic GW interferometer, appropriate coating on sapphire or silicon are
required for good thermal and homogeneity properties. Large ultrahigh vacuum
components and high attenuating vibration system together with an efficient
metrology system are required and will be addressed. For space interferometry,
drag-free technology is well-developed; weak-light phase locking is
demonstrated in the laboratories while weak-light manipulation technology still
needs developments.


title: Ferromagnetism beyond Lieb's theorem

abstract:
  The noninteracting electronic structures of tight binding models on bipartite
lattices with unequal numbers of sites in the two sublattices have a number of
unique features, including the presence of spatially localized eigenstates and
flat bands. When a \emph{uniform} on-site Hubbard interaction $U$ is turned on,
Lieb proved rigorously that at half filling ($\rho=1$) the ground state has a
non-zero spin. In this paper we consider a `CuO$_2$ lattice (also known as
`Lieb lattice', or as a decorated square lattice), in which `$d$-orbitals'
occupy the vertices of the squares, while `$p$-orbitals' lie halfway between
two $d$-orbitals. We use exact Determinant Quantum Monte Carlo (DQMC)
simulations to quantify the nature of magnetic order through the behavior of
correlation functions and sublattice magnetizations in the different orbitals
as a function of $U$ and temperature. We study both the homogeneous (H) case,
$U_d= U_p$, originally considered by Lieb, and the inhomogeneous (IH) case,
$U_d\neq U_p$. For the H case at half filling, we found that the global
magnetization rises sharply at weak coupling, and then stabilizes towards the
strong-coupling (Heisenberg) value, as a result of the interplay between the
ferromagnetism of like sites and the antiferromagnetism between unlike sites;
we verified that the system is an insulator for all $U$. For the IH system at
half filling, we argue that the case $U_p\neq U_d$ falls under Lieb's theorem,
provided they are positive definite, so we used DQMC to probe the cases
$U_p=0,U_d=U$ and $U_p=U, U_d=0$. We found that the different environments of
$d$ and $p$ sites lead to a ferromagnetic insulator when $U_d=0$; by contrast,
$U_p=0$ leads to to a metal without any magnetic ordering. In addition, we have
also established that at density $\rho=1/3$, strong antiferromagnetic
correlations set in, caused by the presence of one fermion on each $d$ site.


title:
Obtaining Gravitational Waves from Inspiral Binary Systems using LIGO
  data

abstract:
  The discovery of the astrophysical events GW150926 and GW151226 has
experimentally confirmed the existence of gravitational waves (GW) and has
demonstrated the existence of binary stellar-mass black hole systems. This
finding marks the beginning of a new era that will reveal unexpected features
of our universe. This work presents a basic insight to the fundamental theory
of GW emitted by inspiral binary systems and describes the scientific and
technological efforts developed to measure these waves using the
interferometer-based detector called LIGO. Subsequently, the work presents a
comprehensive data analysis methodology based on the matched filter algorithm,
which aims to recovery GW signals emitted by inspiral binary systems of
astrophysical sources. This algorithm was evaluated with freely available LIGO
data containing injected GW waveforms. Results of the experiments performed to
assess detection accuracy showed the recovery of 85% of the injected GW.


title: Theory of noncontact friction for atom-surface interactions

abstract:
  The noncontact (van der Waals) friction is an interesting physical effect
which has been the subject of controversial scientific discussion. The "direct"
friction term due to the thermal fluctuations of the electromagnetic field
leads to a friction force proportional to 1/Z^5 where Z is the atom-wall
distance). The "backaction" friction term takes into account the feedback of
thermal fluctuations of the atomic dipole moment onto the motion of the atom
and scales as 1/Z^8. We investigate noncontact friction effects for the
interactions of hydrogen, ground-state helium and metastable helium atoms with
alpha-quartz (SiO_2), gold (Au) and calcium difluorite (CaF_2). We find that
the backaction term dominates over the direct term induced by the thermal
electromagnetic fluctuations inside the material, over wide distance ranges.
The friction coefficients obtained for gold are smaller than those for SiO_2
and CaF_2 by several orders of magnitude.


title:
Nuclear axial current operators to fourth order in chiral effective
  field theory

abstract:
  We present the complete derivation of the nuclear axial charge and current
operators as well as the pseudoscalar operators to fourth order in the chiral
expansion relative to the dominant one-body contribution using the method of
unitary transformation. We demonstrate that the unitary ambiguity in the
resulting operators can be eliminated by the requirement of renormalizability
and by matching of the pion-pole contributions to the nuclear forces. We give
expressions for the renormalized single-, two- and three-nucleon contributions
to the charge and current operators and pseudoscalar operators including the
relevant relativistic corrections. We also verify explicitly the validity of
the continuity equation.


title:
Broadband angle- and permittivity-insensitive nondispersive optical
  activity based on chiral metamaterials

abstract:
  Because of the strong inherent resonances, the giant optical activity
obtained via chiral metamaterials generally suffers from high dispersion, which
has been a big stumbling block to broadband applications. In this paper, we
propose a type of chiral metamaterial consisting of interconnected metal helix
structures with four-fold symmetry, which exhibits nonresonant Drude-like
response and can therefore avoid the highly dispersive optical activity
resulting from resonances. It shows that the well-designed chiral metamaterial
can achieve nondispersive and pure optical activity with high transmittance in
a broadband frequency range. And the optical activity of multi-layer chiral
metamaterials is proportional to the layer numbers of single-layer chiral
metamaterial. Most remarkably, the broadband behaviors of nondispersive optical
activity and high transmission are insensitive to the incident angles of
electromagnetic waves and permittivity of dielectric substrate, thereby
enabling more flexibility in polarization manipulation.


title: Non-Resonant Two-Photon Transitions in Length and Velocity Gauges

abstract:
  We reexamine the invariance of two-photon transition matrix elements and
corresponding two-photon Rabi frequencies under the "gauge" transformation from
the length to the velocity gauge. It is shown that gauge invariance, in the
most general sense, only holds at exact resonance, for both one-color as well
as two-color absorption. The arguments leading to this conclusion are supported
by analytic calculations which express the matrix elements in terms of
hypergeometric functions, and ramified by a "master identity" which is
fulfilled by off-diagonal matrix elements of the Schroedinger propagator under
a the transformation from the velocity to the length gauge. The study of the
gauge dependence of atomic processes highlights subtle connections between the
concept of asymptotic states, the gauge transformation of the wave function,
and infinitesimal damping parameters for perturbations and interaction
Hamiltonians that switch off the terms in the infinite past and future [of the
form exp(-epsilon * | t |)]. We include a pertinent discussion.


title:
Magic wavelength for the hydrogen 1S-2S transition: Contribution of the
  continuum and the reduced-mass correction

abstract:
  Recently, we studied the magic wavelength for the atomic hydrogen 1S-2S
transition [A.K., Phys. Rev. A 92, 042507 (2015)]. An explicit summation over
virtual atomic states of the discrete part of the hydrogen spectrum was
performed to evaluate the atomic polarizability. In this paper, we supplement
the contribution of the continuum part of the spectrum and add the reduced-mass
correction. The magic wavelength, at which the lowest-order ac Stark shifts of
the 1S and 2S states are equal, is found to be equal to 514.6 nm. The ac Stark
shift at the magic wavelength is -221.6 Hz / (kW/cm^2), and the slope of the ac
Stark shift at the magic wavelength under a change of the driving laser
frequency is -0.2157 Hz/ (GHz kW/cm^2).


title: A Chain-Detection Algorithm for Two-Dimensional Grids

abstract:
  We describe a general method of detecting valid chains or links of pieces on
a two-dimensional grid. Specifically, using the example of the chess variant
known as Switch-Side Chain-Chess (SSCC). Presently, no foolproof method of
detecting such chains in any given chess position is known and existing graph
theory, to our knowledge, is unable to fully address this problem either. We
therefore propose a solution implemented and tested using the C++ programming
language. We have been unable to find an incorrect result and therefore offer
it as the most viable solution thus far to the chain-detection problem in this
chess variant. The algorithm is also scalable, in principle, to areas beyond
two-dimensional grids such as 3D analysis and molecular chemistry.


title: Robust self-testing of many-qubit states

abstract:
  We introduce a simple two-player test which certifies that the players apply
tensor products of Pauli $\sigma_X$ and $\sigma_Z$ observables on the tensor
product of $n$ EPR pairs. The test has constant robustness: any strategy
achieving success probability within an additive $\varepsilon$ of the optimal
must be $\mathrm{poly}(\varepsilon)$-close, in the appropriate distance
measure, to the honest $n$-qubit strategy. The test involves $2n$-bit questions
and $2$-bit answers. The key technical ingredient is a quantum version of the
classical linearity test of Blum, Luby, and Rubinfeld.
  As applications of our result we give (i) the first robust self-test for $n$
EPR pairs; (ii) a quantum multiprover interactive proof system for the local
Hamiltonian problem with a constant number of provers and classical questions
and answers, and a constant completeness-soundness gap independent of system
size; (iii) a robust protocol for delegated quantum computation.


title: On Seneta-Heyde Scaling for a stable branching random walk

abstract:
  We consider a discrete-time branching random walk in the boundary case, where
the associated random walk is in the domain of attraction of an $\alpha$-stable
law with $1<\alpha<2$. We prove that the derivative martingale $D_n$ converges
to a non-trivial limit $D_\infty$ under some regular conditions. We also study
the additive martingale $W_n$, and prove $n^\frac{1}{\alpha}W_n$ converges in
probability to a constant multiple of $D_\infty$.


title: Interface high-temperature superconductivity

abstract:
  Cuprate high temperature superconductors consist of two quasi-two-dimensional
(2D) substructures: CuO2 superconducting layers and charge reservoir layers.
The superconductivity is realized by charge transfer from the charge reservoir
layers into the superconducting layers without chemical dopants and defects
being introduced into the latter, similar to modulation-doping in semiconductor
superlattices of AlGaAs/GaAs. Inspired by this scheme, we have been searching
for high temperature superconductivity in ultrathin films of superconductors
epitaxially grown on semiconductor/oxide substrates since 2008. We have
observed interface enhanced superconductivity in both conventional and
unconventional superconducting films, including single atomic layer films of Pb
and In on Si substrates and single unit cell (UC) films of FeSe on SrTiO3 (STO)
substrates. The discovery of high temperature superconductivity with a
superconducting gap of ~20 meV in 1UC-FeSe/STO has stimulated tremendous
interest in superconductivity community, for it opens new avenue for both
raising superconducting transition temperature and understanding the pairing
mechanism of unconventional high temperature superconductivity. Here, we review
mainly the experimental progress on interface enhanced superconductivity in the
three systems mentioned above with emphasis on 1UC-FeSe/STO, studied by
scanning tunneling microscopy/spectroscopy, angle-resolved photoemission
spectroscopy and transport experiments. We discuss the roles of interfaces and
possible pairing mechanism inferred from those studies.


title: Minimax Filter: Learning to Preserve Privacy from Inference Attacks

abstract:
  Preserving privacy of continuous and/or high-dimensional data such as images,
videos and audios, can be challenging with syntactic anonymization methods
which are designed for discrete attributes. Differential privacy, which
provides a more formal definition of privacy, has shown more success in
sanitizing continuous data. However, both syntactic and differential privacy
are susceptible to inference attacks, i.e., an adversary can accurately infer
sensitive attributes from sanitized data. The paper proposes a novel
filter-based mechanism which preserves privacy of continuous and
high-dimensional attributes against inference attacks. Finding the optimal
utility-privacy tradeoff is formulated as a min-diff-max optimization problem.
The paper provides an ERM-like analysis of the generalization error and also a
practical algorithm to perform the optimization. In addition, the paper
proposes an extension that combines minimax filter and differentially-private
noisy mechanism. Advantages of the method over purely noisy mechanisms is
explained and demonstrated with examples. Experiments with several real-world
tasks including facial expression classification, speech emotion
classification, and activity classification from motion, show that the minimax
filter can simultaneously achieve similar or better target task accuracy and
lower inference accuracy, often significantly lower than previous methods.


title: New p- and n-type ferromagnetic semiconductors: Cr-doped BaZn2As2

abstract:
  We find new ferromagnetic semiconductors, Cr-doped BaZn2As2, by employing a
combined method of the density functional theory and the quantum Monte Carlo
simulation. Due to a narrow band gap of 0.2 eV in host BaZn2As2 and the
different hybridization of 3d orbitals of Cr impurity, the impurity bound
states have been induced both below the top of valence band and above the
bottom of conduction band. The long-range ferromagnetic coupling between Cr
impurities is obtained with both p- and n-type carriers.


title: Monitoring the Top-m Aggregation in a Sliding Window of Spatial Queries

abstract:
  In this paper, we propose and study the problem of top-m rank aggregation of
spatial objects in streaming queries, where, given a set of objects O, a stream
of spatial queries (kNN or range), the goal is to report m objects with the
highest aggregate rank. The rank of an object w.r.t. an individual query is
computed based on its distance from the query location, and the aggregate rank
is computed from all of the individual rank orderings. Solutions to this
fundamental problem can be used to monitor the popularity of spatial objects,
which in turn can provide new analytical tools for spatial data. Our work draws
inspiration from three different domains: rank aggregation, continuous queries
and spatial databases. To the best of our knowledge, there is no prior work
that considers all three problem domains in a single context. Our problem is
different from the classical rank aggregation problem in the way that the rank
of spatial objects are dependent on streaming queries whose locations are not
known a priori, and is different from the problem of continuous spatial queries
because new query locations can arrive in any region, but do not move. In order
to solve this problem, we show how to upper and lower bound the rank of an
object for any unseen query. Then we propose an approximation solution to
continuously monitor the top-m objects efficiently, for which we design an
Inverted Rank File (IRF) index to guarantee the error bound of the solution. In
particular, we propose the notion of safe ranking to determine whether the
current result is still valid or not when new queries arrive, and propose the
notion of validation objects to limit the number of objects to update in the
top-m results. We also propose an exact solution for applications where an
approximate solution is not sufficient. Last, we conduct extensive experiments
to verify the efficiency and effectiveness of our solutions.


title:
An efficient multiple imputation algorithm for control-based and
  delta-adjusted pattern mixture models using SAS

abstract:
  In clinical trials, mixed effects models for repeated measures (MMRM) and
pattern mixture models (PMM) are often used to analyze longitudinal continuous
outcomes. We describe a simple missing data imputation algorithm for the MMRM
that can be easily implemented in standard statistical software packages such
as SAS PROC MI. We explore the relationship of the missing data distribution in
the control-based and delta-adjusted PMMs with that in the MMRM, and suggest an
efficient imputation algorithm for these PMMs. The unobserved values in PMMs
can be imputed by subtracting the mean difference in the posterior predictive
distributions of missing data from the imputed values in MMRM. We also suggest
a modification of the copy reference imputation procedure to avoid the
possibility that after dropout, subjects from the active treatment arm will
have better mean response trajectory than subjects who stay on the active
treatment. The proposed methods are illustrated by the analysis of an
antidepressant trial.


title:
Global well-posedness for the massive Maxwell-Klein-Gordon equation with
  small critical Sobolev data

abstract:
  In this paper we prove global well-posedness and modified scattering for the
massive Maxwell-Klein-Gordon equation in the Coulomb gauge on
$\mathbb{R}^{1+d}$ $(d \geq 4)$ for data with small critical Sobolev norm. This
extends to the general case $ m^2 > 0 $ the results of Krieger-Sterbenz-Tataru
($d=4,5 $) and Rodnianski-Tao ($ d \geq 6 $), who considered the case $ m=0$.
  We proceed by generalizing the global parametrix construction for the
covariant wave operator and the functional framework from the massless case to
the Klein-Gordon setting. The equation exhibits a trilinear cancelation
structure identified by Machedon-Sterbenz. To treat it one needs sharp $ L^2 $
null form bounds, which we prove by estimating renormalized solutions in null
frames spaces similar to the ones considered by Bejenaru-Herr. To overcome
logarithmic divergences we rely on an embedding property of $ \Box^{-1} $ in
conjunction with endpoint Strichartz estimates in Lorentz spaces.


title: QCMA hardness of ground space connectivity for commuting Hamiltonians

abstract:
  In this work we consider the ground space connectivity problem for commuting
local Hamiltonians. The ground space connectivity problem asks whether it is
possible to go from one (efficiently preparable) state to another by applying a
polynomial length sequence of 2-qubit unitaries while remaining at all times in
a state with low energy for a given Hamiltonian $H$. It was shown in [Gharibian
and Sikora, ICALP'15] that this problem is QCMA-complete for general local
Hamiltonians, where QCMA is defined as QMA with a classical witness and BQP
verifier. Here we show that the commuting version of the problem is also
QCMA-complete. This provides one of the first examples where commuting local
Hamiltonians exhibit complexity theoretic hardness equivalent to general local
Hamiltonians.


title: On Clifford Algebras and Related Finite Groups and Group Algebras

abstract:
  Albuquerque and Majid have shown how to view Clifford algebras $\cl_{p,q}$ as
twisted group rings whereas Chernov has observed that Clifford algebras can be
viewed as images of group algebras of certain 2-groups modulo an ideal
generated by a nontrivial central idempotent. Ablamowicz and Fauser have
introduced a special transposition anti-automorphism of $\cl_{p,q}$, which they
called a "transposition", which reduces to reversion in algebras $\cl_{p,0}$
and to conjugation in algebras $\cl_{0,q}$. The purpose of this paper is to
bring these concepts together in an attempt to investigate how the algebraic
properties of real Clifford algebras, including their periodicity of eight, are
a direct consequence of the central product structure of Salingaros vee groups
viewed as 2-groups.


title:
Nondestructive on-chip detection of optical orbital angular momentum
  through a single plasmonic nanohole

abstract:
  Optical orbital angular momentum (OAM) provides an additional dimension for
photons to carry information in high-capacity optical communication. Although
the practical needs have intrigued the generations of miniaturized devices to
manipulate the OAM modes in various integrated platforms, the on-chip OAM
detection is still challenging to match the newly-developed compact OAM emitter
and OAM transmission fiber. Here, we demonstrate an ultra-compact device, i.e.,
a single plasmonic nanohole, to efficiently measure an optical beam's OAM state
in a nondestructive way. The device size is reduced down to a few hundreds of
nanometers, which can be easily fabricated and installed in the current OAM
devices. It is a flexible and robust way for in-situ OAM monitoring and
detection in optical fiber networks and long-distance optical communication
systems. With proper optimization of the nanohole parameters, this approach
could be further extended to discriminate the OAM information multiplexed in
multiple wavelengths and polarizations.


title: A Paradigm for Situated and Goal-Driven Language Learning

abstract:
  A distinguishing property of human intelligence is the ability to flexibly
use language in order to communicate complex ideas with other humans in a
variety of contexts. Research in natural language dialogue should focus on
designing communicative agents which can integrate themselves into these
contexts and productively collaborate with humans. In this abstract, we propose
a general situated language learning paradigm which is designed to bring about
robust language agents able to cooperate productively with humans.


title: Inkjet Printed Wire-Grid Polarizers for the THz Frequency Range

abstract:
  We have investigated the use of inkjet printing technology for the production
of THz range wire-grid polarizers using time-domain terahertz spectroscopy
(TDTS). Such technology affords an inexpensive and reproducible way of quickly
manufacturing THz range metamaterial structures. As a proof-of-concept
demonstration, numerous thin silver-nanoparticle ink lines were printed using a
Dimatix DMP-2831 printer. We investigated the optimal printing geometry of the
polarizers by examining a number of samples with printed wires of varying
thickness and spacing. We also investigated the polarization properties of
multiply-stacked polarizers.


title: New families of Strictly optimal Frequency hopping sequence sets

abstract:
  Frequency hopping sequences (FHSs) with favorable partial Hamming correlation
properties have important applications in many synchronization and
multiple-access systems. In this paper, we investigate constructions of FHS
sets with optimal partial Hamming correlation. We present several direct
constructions for balanced nested cyclic difference packings (BNCDPs) and
balanced nested cyclic relative difference packings (BNCRDPs) such that both of
them have a special property by using trace functions and discrete logarithm.
We also show three recursive constructions for FHS sets with partial Hamming
correlation, which are based on cyclic difference matrices and discrete
logarithm. Combing these BNCDPs, BNCRDPs and three recursive constructions, we
obtain infinitely many new strictly optimal FHS sets with respect to the
Peng-Fan bounds.


title:
How Many Components should be Retained from a Multivariate Time Series
  PCA?

abstract:
  We report on the results of two new approaches to considering how many
principal components to retain from an analysis of a multivariate time series.
The first is by using a "heat map" based approach. A heat map in this context
refers to a series of principal component coefficients created by applying a
sliding window to a multivariate time series. Furthermore the heat maps can
provide detailed insights into the evolution of the structure of each principal
component over time. The second is by examining the change of the angle of the
principal component over time within the high-dimensional data space. We
provide evidence that both are useful in studying structure and evolution of a
multivariate time series.


title:
Perfectly-matched-layer boundary integral equation method for wave
  scattering in a layered medium

abstract:
  For scattering problems of time-harmonic waves, the boundary integral
equation (BIE) methods are highly competitive, since they are formulated on
lower-dimension boundaries or interfaces, and can automatically satisfy
outgoing radiation conditions. For scattering problems in a layered medium,
standard BIE methods based on the Green's function of the background medium
must evaluate the expensive Sommefeld integrals. Alternative BIE methods based
on the free-space Green's function give rise to integral equations on unbounded
interfaces which are not easy to truncate, since the wave fields on these
interfaces decay very slowly. We develop a BIE method based on the perfectly
matched layer (PML) technique. The PMLs are widely used to suppress outgoing
waves in numerical methods that directly discretize the physical space. Our
PML-based BIE method uses the Green's function of the PML-transformed free
space to define the boundary integral operators. The method is efficient, since
the Green's function of the PML-transformed free space is easy to evaluate and
the PMLs are very effective in truncating the unbounded interfaces. Numerical
examples are presented to validate our method and demonstrate its accuracy.


title: Quantized magnetization density in periodically driven systems

abstract:
  We study micromotion in two-dimensional periodically driven systems in which
all bulk Floquet eigenstates are localized by disorder. We show that this
micromotion gives rise to a quantized time-averaged magnetization density when
the system is filled with fermions. Furthermore we find that a quantized
current flows around the boundary of any filled region of finite extent. The
quantization has a topological origin: we relate the time-averaged
magnetization density to the winding number characterizing the new phase
identified in Phys. Rev. X 6, 021013 (2016). We thus establish that the winding
number invariant can be accessed directly in bulk measurements, and propose an
experimental protocol to do so using interferometry in cold atom based
realizations.


title: On the existence of a strong minimal pair

abstract:
  We show that there is a strong minimal pair in the computably enumerable
Turing degrees.


title: On statistical learning via the lens of compression

abstract:
  This work continues the study of the relationship between sample compression
schemes and statistical learning, which has been mostly investigated within the
framework of binary classification. The central theme of this work is
establishing equivalences between learnability and compressibility, and
utilizing these equivalences in the study of statistical learning theory.
  We begin with the setting of multiclass categorization (zero/one loss). We
prove that in this case learnability is equivalent to compression of
logarithmic sample size, and that uniform convergence implies compression of
constant size.
  We then consider Vapnik's general learning setting: we show that in order to
extend the compressibility-learnability equivalence to this case, it is
necessary to consider an approximate variant of compression.
  Finally, we provide some applications of the compressibility-learnability
equivalences:
  (i) Agnostic-case learnability and realizable-case learnability are
equivalent in multiclass categorization problems (in terms of sample
complexity).
  (ii) This equivalence between agnostic-case learnability and realizable-case
learnability does not hold for general learning problems: There exists a
learning problem whose loss function takes just three values, under which
agnostic-case and realizable-case learnability are not equivalent.
  (iii) Uniform convergence implies compression of constant size in multiclass
categorization problems. Part of the argument includes an analysis of the
uniform convergence rate in terms of the graph dimension, in which we improve
upon previous bounds.
  (iv) A dichotomy for sample compression in multiclass categorization
problems: If a non-trivial compression exists then a compression of logarithmic
size exists.
  (v) A compactness theorem for multiclass categorization problems.


title: Vojta's conjecture for singular varieties

abstract:
  We formulate a generalization of Vojta's conjecture in terms of log pairs and
variants of multiplier ideals. In this generalization, a variety is allowed to
have singularities. It turns out that the generalized conjecture for a log pair
is equivalent to the original conjecture applied to a log resolution of the
pair. A special case of the generalized conjecture can be interpreted as
representing a general phenomenon that there tend to exist more rational points
near singular points than near smooth points. The same phenomenon is also
observed in relation between greatest common divisors of integer pairs
satisfying an algebraic equation and plane curve singularities, which is
discussed in Appendix. As an application of the generalization of Vojta's
conjecture, we also derive a generalization of a geometric conjecture of Lang
concering varieties of general type to singular varieties and log pairs.


title: Constraining the PopIII IMF with high-z GRBs

abstract:
  We study the possibility to detect and distinguish signatures of enrichment
from PopIII stars in observations of PopII GRBs (GRBIIs) at high redshift by
using numerical N-body/hydrodynamical simulations including atomic and
molecular cooling, star formation and metal spreading from stellar populations
with different initial mass functions (IMFs), yields and lifetimes. PopIII and
PopII star formation regimes are followed simultaneously and both a top-heavy
and a Salpeter-like IMF for pristine PopIII star formation are adopted. We find
that the fraction of GRBIIs hosted in a medium previously enriched by PopIII
stars (PopIII-dominated) is model independent. Typical abundance ratios, such
as [Si/O] vs [C/O] and [Fe/C] vs [Si/C], can help to disentangle enrichment
from massive and intermediate PopIII stars, while low-mass first stars are
degenerate with regular PopII generations. The properties of galaxies hosting
PopIII-dominated GRBIIs are not very sensitive to the particular assumption on
the mass of the first stars.


title: Towards a Theoretical Analysis of PCA for Heteroscedastic Data

abstract:
  Principal Component Analysis (PCA) is a method for estimating a subspace
given noisy samples. It is useful in a variety of problems ranging from
dimensionality reduction to anomaly detection and the visualization of high
dimensional data. PCA performs well in the presence of moderate noise and even
with missing data, but is also sensitive to outliers. PCA is also known to have
a phase transition when noise is independent and identically distributed;
recovery of the subspace sharply declines at a threshold noise variance.
Effective use of PCA requires a rigorous understanding of these behaviors. This
paper provides a step towards an analysis of PCA for samples with
heteroscedastic noise, that is, samples that have non-uniform noise variances
and so are no longer identically distributed. In particular, we provide a
simple asymptotic prediction of the recovery of a one-dimensional subspace from
noisy heteroscedastic samples. The prediction enables: a) easy and efficient
calculation of the asymptotic performance, and b) qualitative reasoning to
understand how PCA is impacted by heteroscedasticity (such as outliers).


title: Dynamical Pattern Selection of Growing Cellular Mosaic in Fish Retina

abstract:
  A Markovian lattice model for photoreceptor cells is introduced to describe
the growth of mosaic patterns on fish retina. The radial stripe pattern
observed in wild-type zebrafish is shown to be selected naturally during the
retina growth, against the geometrically equivalent, circular stripe pattern.
The mechanism of such dynamical pattern selection is clarified on the basis of
both numerical simulations and theoretical analyses, which find that the
successive emergence of local defects plays a critical role in the realization
of the wild-type pattern.


title:
Search for Proton Decay via $p \to e^+\pi^0$ and $p \to \mu^+\pi^0$ in
  0.31 megaton$\cdot$years exposure of the Super-Kamiokande Water Cherenkov
  Detector

abstract:
  We have searched for proton decay via $p \rightarrow e^{+} \pi^{0}$ and $p
\rightarrow \mu^{+} \pi^{0}$ using Super-Kamiokande data from April 1996 to
March 2015, 0.306 megaton$\cdot$years exposure in total. The atmospheric
neutrino background rate in Super-Kamiokande IV is reduced to almost half that
of phase I-III by tagging neutrons associated with neutrino interactions. The
reach of the proton lifetime is further enhanced by introducing new signal
criteria that select the decay of a proton in a hydrogen atom. No candidates
were seen in the $p \rightarrow e^{+} \pi^{0}$ search. Two candidates that
passed all of the selection criteria for $p \rightarrow \mu^{+} \pi^{0}$ have
been observed, but these are consistent with the expected number of background
events of 0.87. Lower limits on the proton lifetime are set at $\tau/B(p
\rightarrow e^{+} \pi^{0}) > 1.6 \times 10^{34}$ years and $\tau/B(p
\rightarrow \mu^{+} \pi^{0}) > 7.7 \times 10^{33}$ years at 90% confidence
level.


title: Asymptotic behavior of $\beta$-polygon flows

abstract:
  In this article we investigate a family of nonlinear evolutions of polygons
in the plane called the $\beta$-polygon flow and obtain some results analogous
to results for the smooth curve shortening flow: (1) any planar polygon shrinks
to a point and (2) a regular polygon with five or more vertices is
asymptotically stable in the sense that nearby polygons shrink to points that
rescale to a regular polygon. In dimension four we show that the shape of a
square is locally stable under perturbations along a hypersurface of all
possible perturbations. Furthermore, we are able to show that under a lower
bound on angles there exists a rescaled sequence extracted from the evolution
that converges to a limiting polygon that is a self-similar solution of the
flow. The last result uses a monotonicity formula analogous to Huisken's for
the curve shortening flow.


title:
Redshift remapping and cosmic acceleration in dark-matter-dominated
  cosmological models

abstract:
  The standard relation between the cosmological redshift and cosmic scale
factor underlies cosmological inference from virtually all kinds of
cosmological observations, leading to the emergence of the LambdaCDM
cosmological model. This relation is not a fundamental theory and thus
observational determination of this function (redshift remapping) should be
regarded as an insightful alternative to holding its standard form in analyses
of cosmological data. Here we present non-parametric reconstructions of
redshift remapping in dark-matter-dominated models and constraints on
cosmological parameters from a joint analysis of all primary cosmological
probes including the local measurement of the Hubble constant, Type Ia
supernovae, baryonic acoustic oscillations (BAO), Planck observations of the
cosmic microwave background (CMB) radiation (temperature power spectrum) and
cosmic chronometers. The reconstructed redshift remapping points to an
additional boost of redshift operating in late epoch of cosmic evolution, but
affecting both low-redshift observations and the CMB. The model predicts a
significant difference between the actual Hubble constant, h=0.48+/-0.02, and
its local determination, h_obs=0.73+/-0.02. The ratio of these two values
coincides closely with the maximum expansion rate inside voids formed in the
corresponding open cosmological model with Omega_m=0.87+/-0.03, whereas the
actual value of the Hubble constant implies the age of the Universe that is
compatible with the Planck LambdaCDM cosmology. The new dark-matter-dominated
model with redshift remapping provides excellent fits to all data and
eliminates recently reported tensions between the Planck LambdaCDM cosmology,
the local determination of the Hubble constant and the BAO measurements from
the Ly-alpha forest of high-redshift quasars.


title:
The imprint of $f(R)$ gravity on weak gravitational lensing II :
  Information content in cosmic shear statistics

abstract:
  We investigate the information content of various cosmic shear statistics on
the theory of gravity. Focusing on the Hu-Sawicki-type $f(R)$ model, we perform
a set of ray-tracing simulations and measure the convergence bispectrum, peak
counts and Minkowski functionals. We first show that while the convergence
power spectrum does have sensitivity to the current value of extra scalar
degree of freedom $|f_{\rm R0}|$, it is largely compensated by a change in the
present density amplitude parameter $\sigma_{8}$ and the matter density
parameter $\Omega_{\rm m0}$. With accurate covariance matrices obtained from
1000 lensing simulations, we then examine the constraining power of the three
additional statistics. We find that these probes are indeed helpful to break
the parameter degeneracy, which can not be resolved from the power spectrum
alone. We show that especially the peak counts and Minkowski functionals have
the potential to rigorously (marginally) detect the signature of modified
gravity with the parameter $|f_{\rm R0}|$ as small as $10^{-5}$ ($10^{-6}$) if
we can properly model them on small ($\sim 1\, \mathrm{arcmin}$) scale in a
future survey with a sky coverage of 1,500 squared degrees. We also show that
the signal level is similar among the additional three statistics and all of
them provide complementary information to the power spectrum. These findings
indicate the importance of combining multiple probes beyond the standard power
spectrum analysis to detect possible modifications to General Relativity.


title: Passive control of a falling sphere by elliptic-shaped appendages

abstract:
  The majority of investigations characterizing the motion of single or
multiple particles in fluid flows consider canonical body shapes, such as
spheres, cylinders, discs, etc. However, protrusions on bodies -- being either
as surface imperfections or appendages that serve a function -- are ubiquitous
in both nature and applications. In this work, we characterize how the dynamics
of a sphere with an axis-symmetric wake is modified in the presence of thin
three-dimensional elliptic-shaped protrusions. By investigating a wide range of
three-dimensional appendages with different aspect ratios and lengths, we
clearly show that the sphere with an appendage may robustly undergo an
inverted-pendulum-like (IPL) instability. This means that the position of the
appendage placed behind the sphere and aligned with the free-stream direction
is unstable, in a similar way that an inverted pendulum is unstable under
gravity. Due to this instability, non-trivial forces are generated on the body,
leading to turn and drift, if the body is free to fall under gravity. Moreover,
we identify the aspect ratio and length of the appendage that induces the
largest side force on the sphere, and therefore also the largest drift for a
freely falling body. Finally, we explain the physical mechanisms behind these
observations in the context of the IPL instability, i.e., the balance between
surface area of the appendage exposed to reversed flow in the wake and the
surface area of the appendage exposed to fast free-stream flow.


title:
Combinatorial differential operators in: Fa\`a di Bruno formula,
  enumeration of ballot paths, enriched rooted trees and increasing rooted
  trees

abstract:
  We obtain a differential equation for the enumeration of the path length of
general increasing trees. By using differential operators and their
combinatorial interpretation we give a bijective proof of a version of Fa\`a di
Bruno formula, and model the generation of ballot and Dyck paths. We get
formulas for its enumeration according with the height of their lattice points.
Recursive formulas for the enumeration of enriched increasing trees and forests
with respect to the height of their internal and external vertices are also
obtained. Finally we present a generalized form of all those results using
one-parameter groups in the general context of formal power series in an
arbitrary number of variables.


title:
Quantitative Studies on the Quantum Critical Regime near Superfluid to
  Mott Insulator Transition

abstract:
  We investigate the critical behaviors of correlation length and critical
exponents for strongly interacting bosons in a two-dimensional optical lattice
via quantum Monte Carlo simulations. By comparing the full numerical results to
those given by the effective theory, we quantitatively determine the critical
regime where the universal scaling behaviors applies for both classical
Berezinskii-Kosterlitz-Thouless transition at a finite temperature and quantum
phase transition from superfluid to Mott insulator. Our results show that the
critical regime can be as large as a few lattice sites in optical lattice and
should be observable in present experimental conditions.


title:
Subspace clustering based on low rank representation and weighted
  nuclear norm minimization

abstract:
  Subspace clustering refers to the problem of segmenting a set of data points
approximately drawn from a union of multiple linear subspaces. Aiming at the
subspace clustering problem, various subspace clustering algorithms have been
proposed and low rank representation based subspace clustering is a very
promising and efficient subspace clustering algorithm. Low rank representation
method seeks the lowest rank representation among all the candidates that can
represent the data points as linear combinations of the bases in a given
dictionary. Nuclear norm minimization is adopted to minimize the rank of the
representation matrix. However, nuclear norm is not a very good approximation
of the rank of a matrix and the representation matrix thus obtained can be of
high rank which will affect the final clustering accuracy. Weighted nuclear
norm (WNN) is a better approximation of the rank of a matrix and WNN is adopted
in this paper to describe the rank of the representation matrix. The convex
program is solved via conventional alternation direction method of multipliers
(ADMM) and linearized alternating direction method of multipliers (LADMM) and
they are respectively refer to as WNNM-LRR and WNNM-LRR(L). Experimental
results show that, compared with low rank representation method and several
other state-of-the-art subspace clustering methods, WNNM-LRR and WNNM-LRR(L)
can get higher clustering accuracy.


title: Indistinguishability as nonlocality constraint

abstract:
  A physical explanation for quantum bounds to nonlocality (Tsirelson's bound)
is a fundamental problem that remains open, and one approach to explaining its
origins is the so-called Exclusivity principle, relying on probabilistic
assumptions shaping general probabilistic theories through sharp measurements
and compatible (non-local) measurements. Information indistinguishability,
presented here as indistinguishability of qubits and more general bits, may
serve as an answer to the nonlocality conundrum, ultimately placing it as the
origin to quantum limits. We connect indistinguishability to the exclusivity
principle and show that indistinguishability leads to quantum bounds. With
that, we suggest indistinguishability to be as fundamental as non-locality and
relativistic causality for nonlocal realism.


title: Maximum entropy models for generation of expressive music

abstract:
  In the context of contemporary monophonic music, expression can be seen as
the difference between a musical performance and its symbolic representation,
i.e. a musical score. In this paper, we show how Maximum Entropy (MaxEnt)
models can be used to generate musical expression in order to mimic a human
performance. As a training corpus, we had a professional pianist play about 150
melodies of jazz, pop, and latin jazz. The results show a good predictive
power, validating the choice of our model. Additionally, we set up a listening
test whose results reveal that on average, people significantly prefer the
melodies generated by the MaxEnt model than the ones without any expression, or
with fully random expression. Furthermore, in some cases, MaxEnt melodies are
almost as popular as the human performed ones.


title:
Activation cross sections of deuteron induced reactions on niobium in
  the 30-50 MeV energy range

abstract:
  Activation cross-sections of deuterons induced reactions on Nb targets were
determined with the aim of different applications and comparison with
theoretical models.


title:
A spatio-temporal model and inference tools for longitudinal count data
  on multicolor cell growth

abstract:
  Multicolor cell spatio-temporal image data have become important to
investigate organ development and regeneration, malignant growth or immune
responses by tracking different cell types both in vivo and in vitro.
Statistical modeling of image data from common longitudinal cell experiments
poses significant challenges due to the presence of complex spatio-temporal
interactions between different cell types and difficulties related to
measurement of single cell trajectories. Current analysis methods focus mainly
on univariate cases, often not considering the spatio-temporal effects
affecting cell growth between different cell populations. In this paper, we
propose a conditional spatial autoregressive model to describe multivariate
count cell data on the lattice, and develop inference tools. The proposed
methodology is computationally tractable and enables researchers to estimate a
complete statistical model of multicolor cell growth. Our methodology is
applied on real experimental data where we investigate how interactions between
cells affect their growth. We include two case studies; the first evaluates
interactions between cancer cells and fibroblasts, which are normally present
in the tumor microenvironment, whilst the second evaluates interactions between
cloned cancer cells when grown as different combinations.


title: On Hyperbolic graphs induced by iterated function systems

abstract:
  For any contractive iterated function system (IFS, including the Moran
systems), we show that there is a natural hyperbolic graph on the symbolic
space, which yields the H\"{o}lder equivalence of the hyperbolic boundary and
the invariant set of the IFS. This completes the previous studies (\cite
{[Ka]}, \cite{[LW1]}, \cite{[W]}) by eliminating superfluous conditions, and
admits more classes of sets (e.g., the Moran sets). We also show that the
bounded degree property of the graph can be used to characterize certain
separation properties of the IFS (open set condition, weak separation
condition); the bounded degree property is particularly important when we
consider random walks on such graphs. This application and the other
application to Lipschitz equivalence of self-similar sets will be discussed.


title: Correlations between real and complex zeros of a random polynomial

abstract:
  Consider a random polynomial $$ G(z):=\xi_0+\xi_1z+\dots+\xi_nz^n,\quad
z\in\mathbb{C}, $$ where $\xi_0,\xi_1,\dots,\xi_{n}$ are independent
real-valued random variables with probability density functions
$f_0,\dots,f_n$. We give an explicit formula for the mixed $(k,l)$-correlation
function $\rho_{k,l}:\mathbb{R}^k\times\mathbb{C}_+^l \to\mathbb{R}_+$ between
$k$ real and $l$ complex zeros of $G_n$.


title:
Law of large numbers for the SIR model with random vertex weights on
  Erd\H{o}s-R\'{e}nyi graph

abstract:
  In this paper we are concerned with the SIR model with random vertex weights
on Erd\H{o}s-R\'{e}nyi graph $G(n,p)$. The Erd\H{o}s-R\'{e}nyi graph $G(n,p)$
is generated from the complete graph $C_n$ with $n$ vertices through
independently deleting each edge with probability $(1-p)$. We assign i. i. d.
copies of a positive r. v. $\rho$ on each vertex as the vertex weights. For the
SIR model, each vertex is in one of the three states `susceptible', `infective'
and `removed'. An infective vertex infects a given susceptible neighbor at rate
proportional to the production of the weights of these two vertices. An
infective vertex becomes removed at a constant rate. A removed vertex will
never be infected again. We assume that at $t=0$ there is no removed vertex and
the number of infective vertices follows a Bernoulli distribution
$B(n,\theta)$. Our main result is a law of large numbers of the model. We give
two deterministic functions $H_S(\psi_t), H_V(\psi_t)$ for $t\geq 0$ and show
that for any $t\geq 0$, $H_S(\psi_t)$ is the limit proportion of susceptible
vertices and $H_V(\psi_t)$ is the limit of the mean capability of an infective
vertex to infect a given susceptible neighbor at moment $t$ as $n$ grows to
infinity.


title:
The Analysis of Local Motion and Deformation in Image Sequences Inspired
  by Physical Electromagnetic Interaction

abstract:
  In order to analyze the moving and deforming of the objects in image
sequence, a novel way is presented to analyze the local changes of object edges
between two related images (such as two adjacent frames in a video sequence),
which is inspired by the physical electromagnetic interaction. The changes of
edge between adjacent frames in sequences are analyzed by simulation of virtual
current interaction, which can reflect the change of the object's position or
shape. The virtual current along the main edge line is proposed based on the
significant edge extraction. Then the virtual interaction between the current
elements in the two related images is studied by imitating the interaction
between physical current-carrying wires. The experimental results prove that
the distribution of magnetic forces on the current elements in one image
applied by the other can reflect the local change of edge lines from one image
to the other, which is important in further analysis.


title:
A Numerical Treatment of Energy Eigenvalues of Harmonic Oscillators
  Perturbed by a Rational Function

abstract:
  In the present contribution, we apply the double exponential Sinc-collocation
method (DESCM) to the one-dimensional time independent Schr\"odinger equation
for a class of rational potentials of the form $V(x) =p(x)/q(x)$. This
algorithm is based on the discretization of the Hamiltonian of the
Schr\"odinger equation using Sinc expansions. This discretization results in a
generalized eigenvalue problem where the eigenvalues correspond to
approximations of the energy values of the corresponding Hamiltonian. A
systematic numerical study is conducted, beginning with test potentials with
known eigenvalues and moving to rational potentials of increasing degree.


title:
A Model of Virtual Carrier Immigration in Digital Images for Region
  Segmentation

abstract:
  A novel model for image segmentation is proposed, which is inspired by the
carrier immigration mechanism in physical P-N junction. The carrier diffusing
and drifting are simulated in the proposed model, which imitates the physical
self-balancing mechanism in P-N junction. The effect of virtual carrier
immigration in digital images is analyzed and studied by experiments on test
images and real world images. The sign distribution of net carrier at the
model's balance state is exploited for region segmentation. The experimental
results for both test images and real-world images demonstrate self-adaptive
and meaningful gathering of pixels to suitable regions, which prove the
effectiveness of the proposed method for image region segmentation.


title:
The Virtual Electromagnetic Interaction between Digital Images for Image
  Matching with Shifting Transformation

abstract:
  A novel way of matching two images with shifting transformation is studied.
The approach is based on the presentation of the virtual edge current in
images, and also the study of virtual electromagnetic interaction between two
related images inspired by electromagnetism. The edge current in images is
proposed as a discrete simulation of the physical current, which is based on
the significant edge line extracted by Canny-like edge detection. Then the
virtual interaction of the edge currents between related images is studied by
imitating the electro-magnetic interaction between current-carrying wires.
Based on the virtual interaction force between two related images, a novel
method is presented and applied in image matching for shifting transformation.
The preliminary experimental results indicate the effectiveness of the proposed
method.


title: Local integrability of Bessel functions on split groups

abstract:
  In this paper, we prove that the Bessel functions are locally integrable for
all connected split reductive linear algebraic groups over a p-adic field $F$
and the Bessel distributions are given by integrals against these Bessel
functions, which are previously known only for $GL(2),GL(3)$ proved by Baruch.


title:
Quantum Correlations of Ideal Bose and Fermi Gases in the Canonical
  Ensemble

abstract:
  We derive an expression for the reduced density matrices of ideal Bose and
Fermi gases in the canonical ensemble, which corresponds to the Bloch--De
Dominicis (or Wick's) theorem in the grand canonical ensemble for
normal-ordered products of operators. Using this expression, we study one- and
two-body correlations of homogeneous ideal gases with $N$ particles. The pair
distribution function $g^{(2)}(r)$ of fermions clearly exhibits antibunching
with $g^{(2)}(0)=0$ due to the Pauli exclusion principle at all temperatures,
whereas that of normal bosons shows bunching with $g^{(2)}(0)\approx 2$,
corresponding to the Hanbury Brown--Twiss effect. For bosons below the
Bose--Einstein condensation temperature $T_0$, an off-diagonal long-range order
develops in the one-particle density matrix to reach $g^{(1)}(r)=1$ at $T=0$,
and the pair correlation starts to decrease towards $g^{(2)}(r)\approx 1$ at
$T=0$. The results for $N\rightarrow \infty$ are seen to converge to those of
the grand canonical ensemble obtained by assuming the average
$\langle\hat\psi({\bf r})\rangle$ of the field operator $\hat\psi({\bf r})$
below $T_0$. This fact justifies the introduction of the "anomalous" average
$\langle\hat\psi({\bf r})\rangle\neq 0$ below $T_0$ in the grand canonical
ensemble as a mathematical means of removing unphysical particle-number
fluctuations to reproduce the canonical results in the thermodynamic limit.

categories: cond-mat.stat-mech cond-mat.quant-gas cond-mat.str-el cond-mat.supr-con


title:
Optimizing Memory Efficiency for Deep Convolutional Neural Networks on
  GPUs

abstract:
  Leveraging large data sets, deep Convolutional Neural Networks (CNNs) achieve
state-of-the-art recognition accuracy. Due to the substantial compute and
memory operations, however, they require significant execution time. The
massive parallel computing capability of GPUs make them as one of the ideal
platforms to accelerate CNNs and a number of GPU-based CNN libraries have been
developed. While existing works mainly focus on the computational efficiency of
CNNs, the memory efficiency of CNNs have been largely overlooked. Yet CNNs have
intricate data structures and their memory behavior can have significant impact
on the performance. In this work, we study the memory efficiency of various CNN
layers and reveal the performance implication from both data layouts and memory
access patterns. Experiments show the universal effect of our proposed
optimizations on both single layers and various networks, with up to 27.9x for
a single layer and up to 5.6x on the whole networks.


title: High-harmonic generation enhanced by dynamical electron correlation

abstract:
  We theoretically study multielectron effects in high-harmonic generation
(HHG), using all-electron first-principles simulations for a one-dimensional
(1D) model atom. In addition to usual plateau and cutoff (from a cation in the
present case, since the neutral is immediately ionized), we find a prominent
resonance peak far above the plateau and a second plateau extended beyond the
first cutoff. These features originate from the dication response enhanced by
orders of magnitude due to the action of the Coulomb force from the
rescattering electron, and, hence, are a clear manifestation of electron
correlation. Although the present simulations are done in 1D, the physical
mechanism underlying the dramatic enhancement is expected to hold also for
three-dimensional real systems. This will provide new possibilities to explore
dynamical electron correlation in intense laser fields using HHG, which is
usually considered to be of single-electron nature in most cases.


title:
Improved results on the nonlinear feedback stabilization of a rotating
  body-beam system

abstract:
  This article is dedicated to the investigation of the stabilization problem
of a flexible beam attached to the center of a rotating disk. We assume that
the feedback law contains a nonlinear torque control applied on the disk and
nonlinear boundary controls exerted on the beam. Thereafter, it is proved that
the proposed controls guarantee the exponential stability of the system under a
realistic smallness condition on the angular velocity of the disk and general
assumptions on the nonlinear functions governing the controls. We used here the
strategy of Lasiecka and Tataru and Alabau-Boussouira. This permits to improve
the stability result shown in \cite{CH:99} in the sense that, on one hand, we
deal with a general form of the nonlinear functions involved in the boundary
controls. On the other hand, we manage to weaken the conditions on those
functions unlike in B. Chentouf and J. F. Couchouron, Nonlinear feedback
stabilization of a rotating body-beam without damping, ESAIM: COCV., 4 (1999),
515-535, where the authors consider a special type of functions that are almost
linear.


title: Nuclear Quantum-Assisted Magnetometer

abstract:
  Magnetic sensing and imaging instruments are important tools in biological
and material sciences. There is an increasing demand for attaining higher
sensitivity and spatial resolution, with implementations using a single qubit
offering potential improvements in both directions. In this article we describe
a scanning magnetometer based on the nitrogen-vacancy center in diamond as the
sensor. By means of a quantum-assisted readout scheme together with advances in
photon collection efficiency, our device exhibits an enhancement in signal to
noise ratio of close to an order of magnitude compared to the standard
fluorescence readout of the nitrogen-vacancy center. This is demonstrated by
comparing non-assisted and assisted methods in a $T_1$ relaxation time
measurement.


title:
Hunting modifications of gravity: from the lab to cosmology via compact
  objects

abstract:
  Modifications of gravity have been considered to model the primordial
inflation and the late-time cosmic acceleration. Provided that modified gravity
models do not suffer from theoretical instabilities, they must be confronted
with observations, not only at the cosmological scales, but also with the local
tests of gravity, in the lab and in the Solar System, as well as at the
astrophysical scales. Considering in particular sub-classes of the Horndeski
gravity, we study their observational predictions at different scales. In order
to pass the local tests of gravity while allowing for long-range interactions
in cosmology, Horndeski gravity exhibits screening mechanisms, among them the
chameleon. The chameleon screening mechanism has been tested recently using
atom interferometry in a vacuum chamber. Numerical simulations are provided in
this thesis in order to refine the analytical predictions. At the astrophysical
scale, Horndeski gravity predicts a variation of the gravitational coupling
inside compact stars. Focusing on Higgs inflation, we discuss to what extent
the Higgs vacuum expectation value varies inside stars and conclude whether the
effect is detectable in gravitational and nuclear physics. Finally, the
covariant Galileon model exhibits non-linearities in the scalar field kinetic
term such that it might pass the local tests of gravity thanks to the
Vainshtein screening mechanism. We discuss if a sub-class of the covariant
Galileon theory dubbed the Fab Four model leads to a viable inflationary phase
and provide combined analysis with neutron stars and Solar System observables.


title: Fast Training of Convolutional Neural Networks via Kernel Rescaling

abstract:
  Training deep Convolutional Neural Networks (CNN) is a time consuming task
that may take weeks to complete. In this article we propose a novel,
theoretically founded method for reducing CNN training time without incurring
any loss in accuracy. The basic idea is to begin training with a pre-train
network using lower-resolution kernels and input images, and then refine the
results at the full resolution by exploiting the spatial scaling property of
convolutions. We apply our method to the ImageNet winner OverFeat and to the
more recent ResNet architecture and show a reduction in training time of nearly
20% while test set accuracy is preserved in both cases.


title: Relativistic dynamics, Green function and pseudodifferential operators

abstract:
  The central role played by pseudodifferential operators in relativistic
dynamics is very well know. In this work, operators as the Schrodinger one
(e.g: square root) are treated from the point of view of the non-local
pseudodifferential Green functions. Starting from the explicit construction of
the Green (semigroup) theoretical kernel, a theorem linking the integrability
conditions and their dependence on the spacetime dimensions is given.
Relativistic wave equations with arbitrary spin and the causality problem are
discussed with the algebraic interpretation of the radical operator and their
relation with coherent and squeezed states. Also we perform by mean of pure
theoretical procedures (based in physical concepts and symmetry) the
relativistic position operator which satisfies the conditions of integrability
: it is non-local, Lorentz invariant and does not have the same problems as the
"local"position operator proposed by Newton and Wigner. Physical examples, as
Zitterbewegung and rogue waves, are presented and deeply analysed in this
theoretical framework.


title: The FSZ properties of sporadic simple groups

abstract:
  We investigate a possible connection between the $FSZ$ properties of a group
and its Sylow subgroups. We show that the simple groups $G_2(5)$ and $S_6(5)$,
as well as all sporadic simple groups with order divisible by $5^6$ are not
$FSZ$, and that neither are their Sylow 5-subgroups. The groups $G_2(5)$ and
$HN$ were previously established as non-$FSZ$ by Peter Schauenburg; we present
alternative proofs. All other sporadic simple groups and their Sylow subgroups
are shown to be $FSZ$. We conclude by considering all perfect groups available
through GAP with order at most $10^6$, and show they are non-$FSZ$ if and only
if their Sylow 5-subgroups are non-$FSZ$.


title: Misaligned Disks in the Binary Protostar IRS 43

abstract:
  Recent high angular resolution ($\sim$0.2") ALMA observations of the 1.1 mm
continuum and of HCO+ J=3-2 and HCN J=3-2 gas towards the binary protostar IRS
43 reveal multiple Keplerian disks which are significantly misaligned ($\gt$
60$^\circ$), both in inclination and position angle and also with respect to
the binary orbital plane. Each stellar component has an associated
circumstellar disk while the binary is surrounded by a circumbinary disk.
Together with archival VLA measurements of the stellar positions over 25 years,
and assuming a circular orbit, we use our continuum measurements to determine
the binary separation, a = 74 $\pm$ 4 AU, and its inclination, i $\lt$
30$^\circ$. The misalignment in this system suggests that turbulence has likely
played a major role in the formation of IRS 43.


title: Computing Integrated Information

abstract:
  Integrated information theory (IIT) has established itself as one of the
leading theories for the study of consciousness. IIT essentially proposes that
quantitative consciousness is identical to maximally integrated conceptual
information, quantified by a measure called $\Phi^{max}$, and that
phenomenological experience corresponds to the associated set of maximally
irreducible cause-effect repertoires of a physical system being in a certain
state. However, in order to ultimately apply the theory to experimental data, a
sufficiently general formulation is needed. With the current work, we provide
this general formulation, which comprehensively and parsimoniously expresses
$\Phi^{max}$ in the language of probabilistic models. Here, the stochastic
process describing a system under scrutiny corresponds to a first-order
time-invariant Markov process, and all necessary mathematical operations for
the definition of $\Phi^{max}$ are fully specified by a system's joint
probability distribution over two adjacent points in discrete time. We present
a detailed constructive rule for the decomposition of a system into two
disjoint subsystems based on flexible marginalization and factorization of this
joint distribution. Furthermore, we suspend the approach of interventional
calculus based on system perturbations, which allows us to omit undefined
conditional distributions and virtualization. We validate our formulation in a
previously established discrete example system, in which we furthermore address
the previously unexplored theoretical issue of quale underdetermination due to
non-uniqueness of maximally irreducible cause-effect repertoires, which in turn
also entails the sensitivity of $\Phi^{max}$ to the shape of the conceptual
structure in qualia space. In constructive spirit, we propose several
modifications of the framework in order to address some of these issues.


title: RetiNet: Automatic AMD identification in OCT volumetric data

abstract:
  Optical Coherence Tomography (OCT) provides a unique ability to image the eye
retina in 3D at micrometer resolution and gives ophthalmologist the ability to
visualize retinal diseases such as Age-Related Macular Degeneration (AMD).
While visual inspection of OCT volumes remains the main method for AMD
identification, doing so is time consuming as each cross-section within the
volume must be inspected individually by the clinician. In much the same way,
acquiring ground truth information for each cross-section is expensive and time
consuming. This fact heavily limits the ability to acquire large amounts of
ground truth, which subsequently impacts the performance of learning-based
methods geared at automatic pathology identification. To avoid this burden, we
propose a novel strategy for automatic analysis of OCT volumes where only
volume labels are needed. That is, we train a classifier in a semi-supervised
manner to conduct this task. Our approach uses a novel Convolutional Neural
Network (CNN) architecture, that only needs volume-level labels to be trained
to automatically asses whether an OCT volume is healthy or contains AMD. Our
architecture involves first learning a cross-section pathology classifier using
pseudo-labels that could be corrupted and then leverage these towards a more
accurate volume-level classification. We then show that our approach provides
excellent performances on a publicly available dataset and outperforms a number
of existing automatic techniques.


title:
The challenge of measuring magnetic fields in strongly pulsating stars:
  the case of HD 96446

abstract:
  Among the early B-type stars, He-rich Bp stars exhibit the strongest
large-scale organized magnetic fields with a predominant dipole contribution.
The presence of $\beta$ Cep-like pulsations in the typical magnetic early
Bp-type star HD 96446 was announced a few years ago, but the analysis of the
magnetic field geometry was hampered by the absence of a reliable rotation
period and a sophisticated procedure for accounting for the impact of
pulsations on the magnetic field measurements. Using new spectropolarimetric
observations and a recently determined rotation period based on an extensive
spectroscopic time series, we investigate the magnetic field model parameters
of this star under more detailed considerations of the pulsation behaviour of
the line profiles.


title: Grain structure dependence of coercivity in thin films

abstract:
  We investigated coercive fields of 200nm x 1200nm x 5nm rectangular
nanocrystalline thin films as a function of grain size D using finite elements
simulations. To this end, we created granular finite element models with grain
sizes ranging from 5nm to 60nm, and performed micromagnetic hysteresis
calculations along the y-axis (easy direction) as well as along the x-axis
(hard direction). We then used an extended Random Anisotropy model to interpret
the results and to illustrate the interplay of random anisotropy and shape
induced anisotropy, which is coherent on a much larger scale, in thin films.


title: Possible regular phenomena in EXO 2030+375

abstract:
  In the last 10 years, since its last giant outburst in 2006, regular X-ray
outbursts (type I) were detected every periastron passage in the Be X-ray
binary EXO 2030+375. Recently, however, it was reported that the source started
to show a peculiar behavior: its X-ray flux decreased significantly and type I
outbursts were missed in several cases. At the same time, the spin frequency of
the neutron star, which had been increasing steadily since the end of the 2006
giant outburst, reached a plateau. Very recent observations indicate that the
source is now starting to spin down. These observed phenomena have a striking
similarity with those which took place 20 years ago, just before the source
displayed a sudden orbital phase shift of the outburst peak (1995). This
historical event occurred at the time exactly between the two giant outbursts
(1985 and 2006). These phenomena suggest the system to have an underlying
periodicity of 10.5 years between orbital phase shifts and/or giant outbursts.
The suggested periodicity may reflect some long-period dynamics in the
circumstellar disk of the Be star, due, e.g., to the Kozai-Lidov effect. A
model generating such a periodic change of the Be disk, namely Kozai-Lidov
oscillations in the Be disk, is discussed. If this behavior is really
periodical, another phase shift of the X-ray outburst peak is predicted to
occur around 2016 December.


title: Noise Threshold of Quantum Supremacy

abstract:
  Demonstrating quantum supremacy, a complexity-guaranteed quantum advantage
against over the best classical algorithms by using less universal quantum
devices, is an important near-term milestone for quantum information
processing. Here we develop a threshold theorem for quantum supremacy with
noisy quantum circuits in the pre-threshold region, where quantum error
correction does not work directly. We show that, even in such a region, we can
virtually simulate quantum error correction by postselection. This allows us to
show that the output sampled from the noisy quantum circuits (without
postselection) cannot be simulated efficiently by classical computers based on
a stable complexity theoretical conjecture, i.e., non-collapse of the
polynomial hierarchy. By applying this to fault-tolerant quantum computation
with the surface codes, we obtain the threshold value $2.84\%$ for quantum
supremacy, which is much higher than the standard threshold $0.75\%$ for
universal fault-tolerant quantum computation with the same circuit-level noise
model. Moreover, contrast to the standard noise threshold, the origin of
quantum supremacy in noisy quantum circuits is quite clear; the threshold is
determined purely by the threshold of magic state distillation, which is
essential to gain a quantum advantage.


title:
Perfect state transfer by means of discrete-time quantum walk on
  complete bipartite graphs

abstract:
  We consider a quantum walk with two marked vertices, sender and receiver, and
analyze its application to perfect state transfer on complete bipartite graphs.
First, the situation with both the sender and the receiver vertex in the same
part of the graph is considered. We show that in this case the dynamics of the
quantum walk is independent of the size of the second part and reduces to the
one for the star graph where perfect state transfer is achieved. Second, we
consider the situation where the sender and the receiver vertex are in the
opposite parts of the graph. In such a case the state transfer with unit
fidelity is achieved only when the parts have the same size.


title:
Discontinuous Galerkin Isogeometric Analysis on Non-matching
  Segmentation: Error Estimates and Efficient Solvers

abstract:
  The Isogeometric Analysis (IgA) of boundary value problems in complex domains
often requires a decomposition of the computational domain into patches such
that each of which can be parametrized by the so-called geometrical mapping. In
this paper, we develop discontinuous Galerkin (dG) IgA techniques for solving
elliptic diffusion problems on decompositions that can include non-matching
parametrizations of the interfaces, i.e., the interfaces of the adjacent
patches may be not identical. The lack of the exact parametrization of the
patches leads to the creation of gap and overlapping regions between the
patches. This does not allow the immediate use of the classical numerical
fluxes that are known in the literature. The unknown normal fluxes of the
solution on the non-matching interfaces are approximated by Taylor expansions
using the values of the solution computed on the boundary of the patches These
approximations are used in order to build up the numerical fluxes of the final
dG IgA scheme and to couple the local patch-wise discrete problems. The
resulting linear systems are solved by using efficient domainecomposition
methods based on the tearing and interconnecting technology. We present
numerical results of a series of test problems that validate the theoretical
estimates presented.


title:
Quantification of Probe-Sample Electrostatic Forces with Dynamic Atomic
  Force Microscopy

abstract:
  Atomic Force Microscopy (AFM) methods utilizing resonant mechanical
vibrations of cantilevers in contact with a sample surface have shown
sensitivities as high as few picometers for detecting surface displacements.
Such a high sensitivity is harnessed in several AFM imaging modes. Here, we
demonstrate a cantilever-resonance-based method to quantify electrostatic
forces on a probe arising in the presence of a surface potential or when a bias
voltage is applied to the AFM probe. We find that the electrostatic forces
acting on the probe tip apex can strongly dominate cantilever response in
electromechanical measurements and produce signals equivalent to few pm of
surface displacement. In combination with modeling, the measurements of the
force were used to determine the strength of the electrical field at the probe
tip apex in contact with a sample. We find an evidence that the electric field
strength in the junctions is limited by about 0.5 V/nm. This field can be
sufficiently strong to significantly influence material states and kinetic
processes through charge injection, Maxwell stress, shifts of phase equilibria,
and reduction of energy barriers for activated processes. Besides, the results
provide a baseline for accounting for the effects of local electrostatic forces
in electromechanical AFM measurements as well as offer additional means to
probe ionic mobility and field-induced phenomena in solids.


title:
Microscopic derivation of magnon spin current in a topological
  insulator/ferromagnet heterostructure

abstract:
  We investigate a spin-electricity conversion effect in a topological
insulator/ferromagnet heterostructure. In the spin-momentum-locked surface
state, an electric current generates nonequilibrium spin accumulation, which
causes a spin-orbit torque that acts on the ferromagnet. When spins in the
ferromagnet are completely parallel to the accumulated spin, this spin-orbit
torque is zero. In the presence of spin excitations, however, a coupling
between magnons and electrons enables us to obtain a nonvanishing torque. In
this paper, we consider a model of the heterostructure in which a
three-dimensional magnon gas is coupled with a two-dimensional massless Dirac
electron system at the interface. We calculate the torque induced by an
electric field, which can be interpreted as a magnon spin current, up to the
lowest order of the electron-magnon interaction. We derive the expressions for
high and low temperatures and estimate the order of magnitude of the induced
spin current for realistic materials at room temperature.


title:
Abundance for non-uniruled 3-folds with non-trivial Albanese maps in
  positive characteristics

abstract:
  In this paper, we prove abundance for non-uniruled 3-folds with non-trivial
Albanese maps, over an algebraically closed field of characteristic $p > 5$. As
an application we get a characterization of abelian 3-folds.


title: Zero Lie product determined Banach algebras

abstract:
  A Banach algebra $A$ is said to be zero Lie product determined if every
continuous bilinear functional $\varphi \colon A\times A\to \mathbb{C}$ with
the property that $\varphi(a,b)=0$ whenever $a$ and $b$ commute is of the form
$\varphi(a,b)=\tau(ab-ba)$ for some $\tau\in A^*$. In the first part of the
paper we give some general remarks on this class of algebras. In the second
part we consider amenable Banach algebras and show that all group algebras
$L^1(G)$ with $G$ an amenable locally compact group are zero Lie product
determined.


title: Electromagnetic wave propagation through a slab of a dispersive medium

abstract:
  A method is proposed for the analysis of the propagation of electromagnetic
waves through a homogeneous slab of a medium with Drude-Lorentz dispersion
behavior, and excited by a causal sinusoidal source. An expression of the time
dependent field, free from branch-cuts in the plane of complex frequencies, is
established. This method provides the complete temporal response in both the
steady-state and transient regimes in terms of discrete poles contributions.
The Sommerfeld and Brillouin precursors are retrieved and the corresponding set
of poles are identified. In addition, the contribution in the transient field
of the resonance frequency in the Drude-Lorentz model is exhybited, and the
effect of reflections resulting from the refractive index mismatch at the
interfaces of the slab are analyzed.


title: Analyzing the Affect of a Group of People Using Multi-modal Framework

abstract:
  Millions of images on the web enable us to explore images from social events
such as a family party, thus it is of interest to understand and model the
affect exhibited by a group of people in images. But analysis of the affect
expressed by multiple people is challenging due to varied indoor and outdoor
settings, and interactions taking place between various numbers of people. A
few existing works on Group-level Emotion Recognition (GER) have investigated
on face-level information. Due to the challenging environments, face may not
provide enough information to GER. Relatively few studies have investigated
multi-modal GER. Therefore, we propose a novel multi-modal approach based on a
new feature description for understanding emotional state of a group of people
in an image. In this paper, we firstly exploit three kinds of rich information
containing face, upperbody and scene in a group-level image. Furthermore, in
order to integrate multiple person's information in a group-level image, we
propose an information aggregation method to generate three features for face,
upperbody and scene, respectively. We fuse face, upperbody and scene
information for robustness of GER against the challenging environments.
Intensive experiments are performed on two challenging group-level emotion
databases to investigate the role of face, upperbody and scene as well as
multi-modal framework. Experimental results demonstrate that our framework
achieves very promising performance for GER.


title: Genericity of weak-mixing measures on geometrically finite manifolds

abstract:
  Let $M$ be a manifold with pinched negative sectional curvature. We show that
when $M$ is geometrically finite and the geodesic flow on $T^1 M$ is
topologically mixing then the set of mixing invariant measures is dense in the
set $\mathscr{M}^1(T^1M)$ of invariant probability measures. This implies that
the set of weak-mixing measures which are invariant by the geodesic flow is a
dense $G_{\delta}$ subset of $\mathscr{M}^1(T^1 M)$. We also show how to extend
these results to manifolds with cusps or with constant negative curvature.