title:
Stochastic Optimal Control with Delay in the Control I: solving the HJB
  equation through partial smoothing

abstract:
  Stochastic optimal control problems governed by delay equations with delay in
the control are usually more difficult to study than the the ones when the
delay appears only in the state. This is particularly true when we look at the
associated Hamilton-Jacobi-Bellman (HJB) equation. Indeed, even in the
simplified setting (introduced first by Vinter and Kwong for the deterministic
case) the HJB equation is an infinite dimensional second order semilinear
Partial Differential Equation (PDE) that does not satisfy the so-called
"structure condition" which substantially means that the control can act on the
system modifying its dynamics at most along the same directions along which the
noise acts.
  The absence of such condition, together with the lack of smoothing properties
which is a common feature of problems with delay, prevents the use of the known
techniques (based on Backward Stochastic Differential Equations (BSDEs) or on
the smoothing properties of the linear part) to prove the existence of regular
solutions of this HJB equation and so no results on this direction have been
proved till now.
  In this paper we provide a result on existence of regular solutions of such
kind of HJB equations. This opens the road to prove existence of optimal
feedback controls, a task that will be accomplished in a companion paper. The
main tool used is a partial smoothing property that we prove for the transition
semigroup associated to the uncontrolled problem. Such results hold for a
specific class of equations and data which arises naturally in many applied
problems.


title:
Accelerated quantum control using superadiabatic dynamics in a
  solid-state lambda system

abstract:
  Adiabatic evolutions find widespread utility in applications to quantum state
engineering, geometric quantum computation, and quantum simulation. Although
offering robustness to experimental imperfections, adiabatic processes are
susceptible to decoherence due to their long evolution time. A general strategy
termed "shortcuts to adiabaticity" (STA) aims to remedy this vulnerability by
designing fast dynamics to reproduce the results of slow, adiabatic evolutions.
Here, we implement a novel STA technique known as "superadiabatic
transitionless driving" (SATD) to speed up stimulated Raman adiabatic passage
(STIRAP) in a solid-state lambda ({\Lambda}) system. Utilizing optical
transitions to a dissipative excited state in the nitrogen-vacancy (NV) center
in diamond, we demonstrate the accelerated performance of different shortcut
trajectories for population transfer and for the initialization and transfer of
coherent superpositions. We reveal that SATD protocols exhibit robustness to
dissipation and experimental uncertainty, and can be optimized when these
effects are present. These results motivate STA as a promising tool for
controlling open quantum systems comprising individual or hybrid
nanomechanical, superconducting, and photonic elements in the solid state.


title:
Matrix product states and equivariant topological field theories for
  bosonic symmetry-protected topological phases in (1+1) dimensions

abstract:
  Matrix Product States (MPSs) provide a powerful framework to study and
classify gapped quantum phases --symmetry-protected topological (SPT) phases in
particular--defined in one dimensional lattices. On the other hand, it is
natural to expect that gapped quantum phases in the limit of zero correlation
length are described by topological quantum field theories (TFTs or TQFTs). In
this paper, for (1+1)-dimensional bosonic SPT phases protected by symmetry $G$,
we bridge their descriptions in terms of MPSs, and those in terms of
$G$-equivariant TFTs. In particular, for various topological invariants (SPT
invariants) constructed previously using MPSs, we provide derivations from the
point of view of (1+1) TFTs. We also discuss the connection between boundary
degrees of freedom, which appear when one introduces a physical boundary in SPT
phases, and "open" TFTs, which are TFTs defined on spacetimes with boundaries.


title: Resonant Meta-atoms with Nonlinearities on Demand

abstract:
  Nonlinear light-matter interactions and their applications are constrained by
properties of available materials. The use of metamaterials opens the way to
achieve precise control over electromagnetic properties at a microscopic level,
providing new tools for experimental studies of complex nonlinear phenomena in
photonics. Here a doubly resonant nonlinear meta-atom is proposed, analyzed and
characterized in the GHz spectral range. The underlying structure is composed
of a pair of split rings, resonant at both fundamental and nonlinear
frequencies. The rings share a varactor diode, which serves as a microscopic
source of nonlinearity. Flexible control over the coupling and near- and
far-field patterns are reported, favoring the doubly resonant structure over
other realizations. Relative efficiencies of the second and third harmonics,
generated by the diode, are tailored by dint of the double-ring geometry,
providing a guideline for selecting one frequency against another, using the
design of the auxiliary structures. The on-demand control over the microscopic
nonlinear properties enables developing a toolbox for experimental emulation of
complex nonlinear phenomena.


title: Supermultiplet of $\beta-$deformations from twistors

abstract:
  We consider the supermultiplet of linearized beta-deformation of
$\mathcal{N}=4$ Super Yang-Mills(SYM). It was previously studied on the
gravitational side. We study the supermultiplet of beta-deformations on the
field theory side and we compare two finite-dimensional representations of
$psl(4|4,\bf{R})$ algebra. We show that they are related by an intertwining
operator. We develop a twistor-based approach which could be useful for
studying other finite-dimensional and nonunitary representations in AdS/CFT
correspondence.


title:
Quantum coherence and entanglement preservation in Markovian and
  non-Markovian dynamics via additional qubits

abstract:
  In this paper, we investigate preservation of quantum coherence of a
single-qubit interacting with a zero-temperature thermal reservoir through the
addition of noninteracting qubits in the reservoir. Moreover, we extend this
scheme to preserve quantum entanglement between two and three distant qubits,
each of which interacts with a dissipative reservoir independently. At the long
time limit, we obtained analytical expressions for the coherence measure and
the concurrence of two and three qubits in terms of the number of additional
qubits. It is observed that, by increasing the number of additional qubits in
each reservoir, the initial coherence and the respective entanglements are
completely protected in both Markovian and non-Markovian regimes.
Interestingly, the protection of entanglements occurs even under the
individually different behaviors of the reservoirs.


title:
Stochastic Optimal Control with Delay in the Control II: Verification
  Theorem and Optimal Feedbacks

abstract:
  We consider a stochastic optimal control problem governed by a stochastic
differential equation with delay in the control. Using a result of existence
and uniqueness of a sufficiently regular mild solution of the associated
Hamilton-Jacobi-Bellman (HJB) equation, see the companion paper "Stochastic
Optimal Control with Delay in the Control I: solving the HJB equation through
partial smoothing ", we solve the control problem by proving a Verification
Theorem and the existence of optimal feedback controls.


title: Doubly Balanced Connected Graph Partitioning

abstract:
  We introduce and study the Doubly Balanced Connected graph Partitioning
(DBCP) problem: Let $G=(V,E)$ be a connected graph with a weight
(supply/demand) function $p:V\rightarrow \{-1,+1\}$ satisfying $p(V)=\sum_{j\in
V} p(j)=0$. The objective is to partition $G$ into $(V_1,V_2)$ such that
$G[V_1]$ and $G[V_2]$ are connected, $|p(V_1)|,|p(V_2)|\leq c_p$, and
$\max\{\frac{|V_1|}{|V_2|},\frac{|V_2|}{|V_1|}\}\leq c_s$, for some constants
$c_p$ and $c_s$. When $G$ is 2-connected, we show that a solution with $c_p=1$
and $c_s=3$ always exists and can be found in polynomial time. Moreover, when
$G$ is 3-connected, we show that there is always a `perfect' solution (a
partition with $p(V_1)=p(V_2)=0$ and $|V_1|=|V_2|$, if $|V|\equiv 0
(\mathrm{mod}~4)$), and it can be found in polynomial time. Our techniques can
be extended, with similar results, to the case in which the weights are
arbitrary (not necessarily $\pm 1$), and to the case that $p(V)\neq 0$ and the
excess supply/demand should be split evenly. They also apply to the problem of
partitioning a graph with two types of nodes into two large connected subgraphs
that preserve approximately the proportion of the two types.


title: Electronic Circuit Analog of Synthetic Genetic Networks: Revisited

abstract:
  Electronic circuits are useful tools for studying potential dynamical
behaviors of synthetic genetic networks. The circuit models are complementary
to numerical simulations of the networks, especially providing a framework for
verification of dynamical behaviors in the presence of intrinsic and extrinsic
noise of the electrical systems. Here we present an improved version of our
previous design of an electronic analog of genetic networks that includes the
3-gene Repressilator and we show conversions between model parameters and real
circuit component values to mimic the numerical results in experiments.
Important features of the circuit design include the incorporation of chemical
kinetics representing Hill function inhibition, quorum sensing coupling, and
additive noise. Especially, we make a circuit design for a systematic change of
initial conditions in experiment, which is critically important for studies of
dynamical systems' behavior, particularly, when it shows multistability. This
improved electronic analog of the synthetic genetic network allows us to extend
our investigations from an isolated Repressilator to coupled Repressilators and
to reveal the dynamical behavior's complexity.


title: Contingent Payment Mechanisms for Resource Utilization

abstract:
  We introduce the problem of assigning resources to improve their utilization.
The motivation comes from settings where agents have uncertainty about their
own values for using a resource, and where it is in the interest of a group
that resources be used and not wasted. Done in the right way, improved
utilization maximizes social welfare--- balancing the utility of a high value
but unreliable agent with the group's preference that resources be used. We
introduce the family of contingent payment mechanisms (CP), which may charge an
agent contingent on use (a penalty). A CP mechanism is parameterized by a
maximum penalty, and has a dominant-strategy equilibrium. Under a set of
axiomatic properties, we establish welfare-optimality for the special case
CP(W), with CP instantiated for a maximum penalty equal to societal value W for
utilization. CP(W) is not dominated for expected welfare by any other
mechanism, and second, amongst mechanisms that always allocate the resource and
have a simple indirect structure, CP(W) strictly dominates every other
mechanism. The special case with no upper bound on penalty, the contingent
second-price mechanism, maximizes utilization. We extend the mechanisms to
assign multiple, heterogeneous resources, and present a simulation study of the
welfare properties of these mechanisms.


title: Transient temperature and mixing times of quantum walks on cycles

abstract:
  The definition of entanglement temperature for the quantum walk on the line
is extended to $N$-cycles, which are more amenable to a physical
implementation. We show that, for these systems, there is a linear connection
between the thermalization time and the mixing time, and also that these
characteristic times become insensitive to the system size when $N$ is larger
than a few units


title: Online First-Order Framework for Robust Convex Optimization

abstract:
  Robust optimization (RO) has emerged as one of the leading paradigms to
efficiently model parameter uncertainty. The recent connections between RO and
problems in statistics and machine learning domains demand for solving RO
problems in ever more larger scale. However, the traditional approaches for
solving RO formulations based on building and solving robust counterparts or
the iterative approaches utilizing nominal feasibility oracles can be
prohibitively expensive and thus significantly hinder the scalability of RO
paradigm. In this paper, we present a general and flexible iterative framework
to approximately solve robust convex optimization problems that is built on a
fully online first-order paradigm. In comparison to the existing literature, a
key distinguishing feature of our approach is that it only requires access to
first-order oracles that are remarkably cheaper than pessimization or nominal
feasibility oracles, while maintaining the same convergence rates. This, in
particular, makes our approach much more scalable and hence preferable in
large-scale applications, specifically those from machine learning and
statistics domains. We also provide new interpretations of existing iterative
approaches in our framework and illustrate our framework on robust quadratic
programming.


title:
Geometric Neural Phrase Pooling: Modeling the Spatial Co-occurrence of
  Neurons

abstract:
  Deep Convolutional Neural Networks (CNNs) are playing important roles in
state-of-the-art visual recognition. This paper focuses on modeling the spatial
co-occurrence of neuron responses, which is less studied in the previous work.
For this, we consider the neurons in the hidden layer as neural words, and
construct a set of geometric neural phrases on top of them. The idea that
grouping neural words into neural phrases is borrowed from the
Bag-of-Visual-Words (BoVW) model. Next, the Geometric Neural Phrase Pooling
(GNPP) algorithm is proposed to efficiently encode these neural phrases. GNPP
acts as a new type of hidden layer, which punishes the isolated neuron
responses after convolution, and can be inserted into a CNN model with little
extra computational overhead. Experimental results show that GNPP produces
significant and consistent accuracy gain in image classification.


title:
The Role of PMESII Modeling in a Continuous Cycle of Anticipation and
  Action

abstract:
  The inevitable incompleteness of any collection of PMESII models, along with
poorly understood methods for combining heterogeneous models, leads to major
uncertainty regarding the reliability of computational tools. This uncertainty
is further exacerbated by difficulties in validation of such tools. They should
only be used as aids to human analysis and decision-making. A practitioner must
wonder: how can we accommodate the uncertainty of a tool's results by applying
human judgment appropriately?
  In this paper, we describe two examples where planners and analysts used (or
could have used) computational tools to obtain estimates of effects of various
actions under consideration. Then they considered these computational estimates
to draw their own conclusions regarding the effects that would likely emerge
from proposed actions taken by the international mission.
  The key idea, in both of our examples, is a continuous cycle of anticipations
and actions; in each cycle computational estimates of effects help intervention
managers determine appropriate actions, and then assessments of real-world
outcomes guide the next increment of computational estimates. With a proper
methodology, PMESII modeling tools can offer valuable insights and encourage
learning, even if they will never produce fully accurate estimates useable in a
customary, strictly predictive manner.


title: Sparse grid techniques for particle-in-cell schemes

abstract:
  We propose the use of sparse grids to accelerate particle-in-cell (PIC)
schemes. By using the so-called `combination technique' from the sparse grids
literature, we are able to dramatically increase the size of the spatial cells
in multi-dimensional PIC schemes while paying only a slight penalty in
grid-based error. The resulting increase in cell size allows us to reduce the
statistical noise in the simulation without increasing total particle number.
We present initial proof-of-principle results from test cases in two and three
dimensions that demonstrate the new scheme's efficiency, both in terms of
computation time and memory usage.


title:
HyperLogLog Hyper Extended: Sketches for Concave Sublinear Frequency
  Statistics

abstract:
  One of the most common statistics computed over data elements is the number
of distinct keys. A thread of research pioneered by Flajolet and Martin three
decades ago culminated in the design of optimal approximate counting sketches,
which have size that is double logarithmic in the number of distinct keys and
provide estimates with a small relative error. Moreover, the sketches are
composable, and thus suitable for streamed, parallel, or distributed
computation.
  We consider here all statistics of the frequency distribution of keys, where
a contribution of a key to the aggregate is concave and grows (sub)linearly
with its frequency. These fundamental aggregations are very common in text,
graphs, and logs analysis and include logarithms, low frequency moments, and
capping statistics.
  We design composable sketches of double-logarithmic size for all concave
sublinear statistics. Our design combines theoretical optimality and practical
simplicity. In a nutshell, we specify tailored mapping functions of data
elements to output elements so that our target statistics on the data elements
is approximated by the (max-) distinct statistics of the output elements, which
can be approximated using off-the-shelf sketches. Our key insight is relating
these target statistics to the {\em complement Laplace} transform of the input
frequencies.


title: Star Formation Relations in the Milky Way

abstract:
  The relations between star formation and properties of molecular clouds are
studied based on a sample of star forming regions in the Galactic Plane.
Sources were selected by having radio recombination lines to provide
identification of associated molecular clouds and dense clumps. Radio continuum
and mid-infrared emission were used to determine star formation rates, while
13CO and submillimeter dust continuum emission were used to obtain masses of
molecular and dense gas, respectively. We test whether total molecular gas or
dense gas provides the best predictor of star formation rate. We also test two
specific theoretical models, one relying on the molecular mass divided by the
free-fall time, the other using the free-fall time divided by the crossing
time. Neither is supported by the data. The data are also compared to those
from nearby star forming regions and extragalactic data. The star formation
"efficiency," defined as star formation rate divided by mass, spreads over a
large range when the mass refers to molecular gas; the standard deviation of
the log of the efficiency decreases by a factor of three when the mass of
relatively dense molecular gas is used rather than the mass of all the
molecular gas.


title: Holographic Computations of the Quantum Information Metric

abstract:
  In this note we show how the Quantum Information Metric can be computed
holographically using a perturbative approach. In particular when the
deformation of the conformal field theory state is induced by a scalar operator
the corresponding bulk configuration reduces to a scalar field perturbatively
probing the unperturbed background. We study two concrete examples: a CFT
ground state deformed by a primary operator and thermofield double state in
$d=2$ deformed by a marginal operator. Finally, we generalize the bulk
construction to the case of a multi dimensional parameter space and show that
the Quantum Information Metric coincides with the metric of the non-linear
sigma model for the corresponding scalar fields.


title:
Man is to Computer Programmer as Woman is to Homemaker? Debiasing Word
  Embeddings

abstract:
  The blind application of machine learning runs the risk of amplifying biases
present in data. Such a danger is facing us with word embedding, a popular
framework to represent text data as vectors which has been used in many machine
learning and natural language processing tasks. We show that even word
embeddings trained on Google News articles exhibit female/male gender
stereotypes to a disturbing extent. This raises concerns because their
widespread use, as we describe, often tends to amplify these biases.
Geometrically, gender bias is first shown to be captured by a direction in the
word embedding. Second, gender neutral words are shown to be linearly separable
from gender definition words in the word embedding. Using these properties, we
provide a methodology for modifying an embedding to remove gender stereotypes,
such as the association between between the words receptionist and female,
while maintaining desired associations such as between the words queen and
female. We define metrics to quantify both direct and indirect gender biases in
embeddings, and develop algorithms to "debias" the embedding. Using
crowd-worker evaluation as well as standard benchmarks, we empirically
demonstrate that our algorithms significantly reduce gender bias in embeddings
while preserving the its useful properties such as the ability to cluster
related concepts and to solve analogy tasks. The resulting embeddings can be
used in applications without amplifying gender bias.


title:
Joint Uplink/Downlink Optimization for Backhaul-Limited Mobile Cloud
  Computing with User Scheduling

abstract:
  Mobile cloud computing enables the offloading of computationally heavy
applications, such as for gaming, object recognition or video processing, from
mobile users (MUs) to cloudlet or cloud servers, which are connected to
wireless access points, either directly or through finite-capacity backhaul
links. In this paper, the design of a mobile cloud computing system is
investigated by proposing the joint optimization of computing and communication
resources with the aim of minimizing the energy required for offloading across
all MUs under latency constraints at the application layer. The proposed design
accounts for multiantenna uplink and downlink interfering transmissions, with
or without cooperation on the downlink, along with the allocation of backhaul
and computational resources and user selection. The resulting design
optimization problems are nonconvex, and stationary solutions are computed by
means of successive convex approximation (SCA) techniques. Numerical results
illustrate the advantages in terms of energy-latency trade-off of the joint
optimization of computing and communication resources, as well as the impact of
system parameters, such as backhaul capacity, and of the network architecture.


title: Single-file escape of colloidal particles from microfluidic channels

abstract:
  Single-file diffusion is a ubiquitous physical process exploited by living
and synthetic systems to exchange molecules with their environment. It is
paramount quantifying the escape time needed for single files of particles to
exit from constraining synthetic channels and biological pores. This quantity
depends on complex cooperative effects, whose predominance can only be
established through a strict comparison between theory and experiments. By
using colloidal particles, optical manipulation, microfluidics, digital
microscopy and theoretical analysis we uncover the self-similar character of
the escape process and provide closed-formula evaluations of the escape time.
We find that the escape time scales inversely with the diffusion coefficient of
the last particle to leave the channel. Importantly, we find that at the
investigated {\bf microscale}, bias forces as tiny as $10^{-15}\;{\rm N}$
determine the magnitude of the escape time by drastically reducing
interparticle collisions. Our findings provide crucial guidelines to optimize
the design of micro- and nano-devices for a variety of applications including
drug delivery, particle filtering and transport in geometrical constrictions.


title: Effect of Laser-Plasma Interactions on Inertial Fusion Hydrodynamics

abstract:
  The effects of laser-plasma interactions (LPI) on the dynamics of inertial
confinement fusion hohlraums is investigated via a new approach that
self-consistently couples reduced LPI models into radiation-hydrodynamics
numerical codes. The interplay between hydrodynamics and LPI -- specifically
stimulated Raman scatter (SRS) and crossed-beam energy transfer (CBET) --
mostly occurs via momentum and energy deposition into Langmuir and ion acoustic
waves. This spatially redistributes energy coupling to the target, which
affects the background plasma conditions and thus modifies laser propagation.
This model shows reduced CBET, and significant laser energy depletion by
Langmuir waves, which reduce the discrepancy between modeling and data from
hohlraum experiments on wall x-ray emission and capsule implosion shape.


title:
Line nodes, Dirac points and Lifshitz transition in 2D nonsymmorphic
  photonic crystals

abstract:
  Topological phase transitions, which have fascinated generations of
physicists, are always demarcated by gap closures. In this work, we propose
very simple 2D photonic crystal lattices with gap closure points, i.e. band
degeneracies protected by nonsymmorphic symmetry. Our photonic structures are
relatively easy to fabricate, consisting of two inequivalent dielectric
cylinders per unit cell. Along high symmetry directions, they exhibit line
degeneracies protected by glide reflection symmetry, which we explicitly
demonstrate for $pg,pmg,pgg$ and $p4g$ nonsymmorphic groups. In the presence of
time reversal symmetry, they also exhibit point degeneracies (Dirac points)
protected by a $Z_2$ topological number associated with crystalline symmetry.
Strikingly, the robust protection of $pg$-symmetry allows a Lifshitz transition
to a type II Dirac cone across a wide range of experimentally accessible
parameters, thus providing a convenient route for realizing anomalous
refraction. Further potential applications include a stoplight device based on
electrically induced strain that dynamically switches the lattice symmetry from
$pgg$ to the higher $p4g$ symmetry. This controls the coalescence of Dirac
points and hence the group velocity within the crystal.


title: CGMOS: Certainty Guided Minority OverSampling

abstract:
  Handling imbalanced datasets is a challenging problem that if not treated
correctly results in reduced classification performance. Imbalanced datasets
are commonly handled using minority oversampling, whereas the SMOTE algorithm
is a successful oversampling algorithm with numerous extensions. SMOTE
extensions do not have a theoretical guarantee during training to work better
than SMOTE and in many instances their performance is data dependent. In this
paper we propose a novel extension to the SMOTE algorithm with a theoretical
guarantee for improved classification performance. The proposed approach
considers the classification performance of both the majority and minority
classes. In the proposed approach CGMOS (Certainty Guided Minority
OverSampling) new data points are added by considering certainty changes in the
dataset. The paper provides a proof that the proposed algorithm is guaranteed
to work better than SMOTE for training data. Further experimental results on 30
real-world datasets show that CGMOS works better than existing algorithms when
using 6 different classifiers.


title:
Beyond the Spectral Theorem: Spectrally Decomposing Arbitrary Functions
  of Nondiagonalizable Operators

abstract:
  Nonlinearities in finite dimensions can be linearized by projecting them into
infinite dimensions. Unfortunately, often the linear operator techniques that
one would then use simply fail since the operators cannot be diagonalized. This
curse is well known. It also occurs for finite-dimensional linear operators. We
circumvent it by developing a meromorphic functional calculus that can
decompose arbitrary functions of nondiagonalizable linear operators in terms of
their eigenvalues and projection operators. It extends the spectral theorem of
normal operators to a much wider class, including circumstances in which poles
and zeros of the function coincide with the operator spectrum. By allowing the
direct manipulation of individual eigenspaces of nonnormal and
nondiagonalizable operators, the new theory avoids spurious divergences. As
such, it yields novel insights and closed-form expressions across several areas
of physics in which nondiagonalizable dynamics are relevant, including
memoryful stochastic processes, open non unitary quantum systems, and
far-from-equilibrium thermodynamics.
  The technical contributions include the first full treatment of arbitrary
powers of an operator. In particular, we show that the Drazin inverse,
previously only defined axiomatically, can be derived as the negative-one power
of singular operators within the meromorphic functional calculus and we give a
general method to construct it. We provide new formulae for constructing
projection operators and delineate the relations between projection operators,
eigenvectors, and generalized eigenvectors.
  By way of illustrating its application, we explore several, rather distinct
examples.

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


title:
Structural Transitions in Fibers of Bent-Core Liquid Crystals from
  Field-Theory Monte Carlo Simulations

abstract:
  Fibers of bent-core liquid crystals present an internal structure of a rolled
smectic layer and can be used as optical waveguides. We used a
field-theoretical Monte Carlo simulation to analyze the internal configuration
of such fibers as a function of the radial coordinate and to study their
equilibrium sates. In contrast to previous studies, we analyzed the fully
nonlinear model proposed in [Bailey et al., Phys. Rev. E, 2007, 75, 031701] and
revised in [P\'erez-Ortiz et al., Phys. Rev. E, 2011, 84, 011701]. We found
that, due to the non-differentiable character of such model, the Euler-Lagrange
equations are not able to find all equilibrium states. Our Monte Carlo
procedure identified both differentiable and non-differentiable equilibria and
first order transitions between them. In all cases, the equilibrium states show
inhomogenous configurations that display a boundary layer. This methodology can
by applied to other models of liquid crystals that have more degrees of
freedom, including those with non-differentiable minima. The equilibrium
structures found can be used as inputs to model the transmission of light along
the liquid crystal fibers.


title:
Designing convex repulsive pair potentials that favor assembly of kagome
  and snub square lattices

abstract:
  Building on a recently introduced inverse strategy, isotropic and convex
repulsive pair potentials were designed that favor assembly of particles into
kagome and equilateral snub square lattices. The former interactions were
obtained by numerical solution of a variational problem that maximizes the
range of density for which the ground state of the potential is the kagome
lattice. Similar optimizations targeting the snub square lattice were also
carried out, employing a constraint that required a minimum chemical potential
advantage of the target over select competing structures. This constraint
helped discover isotropic interactions that meaningfully favored the snub
square lattice as the ground state structure despite the asymmetric spatial
distribution of particles in its coordination shells and the presence of
tightly competing structures. Consistent with earlier published results
[Pi\~neros et al. J. Chem. Phys. 144, 084502 (2016)], enforcement of greater
chemical potential advantages for the target lattice in the interaction
optimization led to assemblies with enhanced thermal stability.


title:
Phantom covering ideals in categories without enough projective
  morphisms

abstract:
  We give sufficient conditions to ensure that the ideal $\Phi(\mathcal E)$ of
$\mathcal E$-phantom maps in a locally $\lambda$-presentable exact category
$(\mathcal{A}, \mathcal{E})$ is (special) (pre)covering ideal, where $\mathcal
E$ is an exact substructure of $(\mathcal{A}, \mathcal{E})$. As a byproduct, we
infer the existence of various covering ideals in categories of sheaves which
have a meaningful geometrical motivation. In particular we deal with a
Zariski-local notion of phantom maps in categories of sheaves. We would like to
point out that our approach is necessarily different from [FGHT13], as the
categories involved in most of the examples we are interested in do not have
enough projective morphisms.


title:
Protecting and enhancing spin squeezing under decoherence using weak
  measurement

abstract:
  We propose an efficient method to protect spin squeezing under the action of
amplitude-damping, depolarizing and phase-damping channels based on measurement
reversal from weak measurement, and consider an ensemble of N independent
spin-1/2 particles with exchange symmetry. We find that spin squeezing can be
enhanced greatly under three different decoherence channels and spin-squeezing
sudden death (SSSD) can be avoided undergoing amplitude damping and
phase-damping channels.


title:
An extension of Minkowski's theorem and its applications to questions
  about projections for measures

abstract:
  Minkowski's Theorem asserts that every centered measure on the sphere which
is not concentrated on a great subsphere is the surface area measure of some
convex body, and, moreover, the surface area measure determines a convex body
uniquely.
  In this manuscript we prove an extension of Minkowski's theorem. Consider a
measure $\mu$ on $\mathbb{R}^n$ with positive degree of concavity and positive
degree of homogeneity. We show that a surface area measure of a convex set $K$,
weighted with respect to $\mu$, determines a convex body uniquely up to
$\mu$-measure zero. We also establish an existence result under natural
conditions including symmetry.
  We apply this result to extend the solution to classical Shephard's problem,
which asks the following: if one convex body in $\mathbb{R}^n$ has larger
projections than another convex body in every direction, does it mean that the
volume of the first convex body is also greater? The answer to this question is
affirmative when $n\leq 2$ and negative when $n\geq 3.$
  In this paper we introduce a new notion which relates projections of convex
bodies to a given measure $\mu$, and is a direct generalization of the Lebesgue
area of a projection. Using this notion we state a generalization of the
Shephard problem to measures and prove that the answer is affirmative for
$n\leq 2$ and negative for $n\geq 3$ for measures which have a positive degree
of homogeneity and a positive degree of concavity. We also prove stability and
separation results, and establish useful corollaries. Finally, we describe two
types of uniqueness results which follow from the extension of Minkowski's
theorem.


title:
Novel Word Embedding and Translation-based Language Modeling for
  Extractive Speech Summarization

abstract:
  Word embedding methods revolve around learning continuous distributed vector
representations of words with neural networks, which can capture semantic
and/or syntactic cues, and in turn be used to induce similarity measures among
words, sentences and documents in context. Celebrated methods can be
categorized as prediction-based and count-based methods according to the
training objectives and model architectures. Their pros and cons have been
extensively analyzed and evaluated in recent studies, but there is relatively
less work continuing the line of research to develop an enhanced learning
method that brings together the advantages of the two model families. In
addition, the interpretation of the learned word representations still remains
somewhat opaque. Motivated by the observations and considering the pressing
need, this paper presents a novel method for learning the word representations,
which not only inherits the advantages of classic word embedding methods but
also offers a clearer and more rigorous interpretation of the learned word
representations. Built upon the proposed word embedding method, we further
formulate a translation-based language modeling framework for the extractive
speech summarization task. A series of empirical evaluations demonstrate the
effectiveness of the proposed word representation learning and language
modeling techniques in extractive speech summarization.


title: VLBI observations of a flared optical quasar CGRaBS J0809+5341

abstract:
  A bright optical flare was detected in the high-redshift ($z=2.133$) quasar
CGRaBS J0809+5341 on 2014 April 13. The absolute magnitude of the object
reached $-30.0$ during the flare, making it the brightest one (in flaring
stage) among all known quasars so far. The 15 GHz flux density of CGRaBS
J0809+5341 monitored in the period from 2008 to 2016 also reached its peak at
the same time. To reveal any structural change possibly associated with the
flare in the innermost radio structure of the quasar, we conducted a pilot very
long baseline interferometry (VLBI) observation of CGRaBS J0809+5341 using the
European VLBI Network (EVN) at 5 GHz on 2014 November 18, about seven months
after the prominent optical flare. Three epochs of follow-up KaVA (Korean VLBI
Network and VLBI Exploration of Radio Astrometry Array) observations were
carried out at 22 and 43 GHz frequencies from 2015 February 25 to June 4, with
the intention of exploring a possibly emerging new radio jet component
associated with the optical flare. However, these high-resolution VLBI
observations revealed only the milliarcsecond-scale compact "core" that was
known in the quasar from earlier VLBI images, and showed no sign of any
extended jet structure. Neither the size, nor the flux density of the "core"
changed considerably after the flare according to our VLBI monitoring. The
results suggest that any putative radio ejecta associated with the major
optical and radio flare could not yet be separated from the "core" component,
or the newly-born jet was short-lived.


title: The Landscape of Empirical Risk for Non-convex Losses

abstract:
  Most high-dimensional estimation and prediction methods propose to minimize a
cost function (empirical risk) that is written as a sum of losses associated to
each data point. In this paper we focus on the case of non-convex losses, which
is practically important but still poorly understood. Classical empirical
process theory implies uniform convergence of the empirical risk to the
population risk. While uniform convergence implies consistency of the resulting
M-estimator, it does not ensure that the latter can be computed efficiently.
  In order to capture the complexity of computing M-estimators, we propose to
study the landscape of the empirical risk, namely its stationary points and
their properties. We establish uniform convergence of the gradient and Hessian
of the empirical risk to their population counterparts, as soon as the number
of samples becomes larger than the number of unknown parameters (modulo
logarithmic factors). Consequently, good properties of the population risk can
be carried to the empirical risk, and we can establish one-to-one
correspondence of their stationary points. We demonstrate that in several
problems such as non-convex binary classification, robust regression, and
Gaussian mixture model, this result implies a complete characterization of the
landscape of the empirical risk, and of the convergence properties of descent
algorithms.
  We extend our analysis to the very high-dimensional setting in which the
number of parameters exceeds the number of samples, and provide a
characterization of the empirical risk landscape under a nearly
information-theoretically minimal condition. Namely, if the number of samples
exceeds the sparsity of the unknown parameters vector (modulo logarithmic
factors), then a suitable uniform convergence result takes place. We apply this
result to non-convex binary classification and robust regression in very
high-dimension.


title: Embedded Diagrams of Kerr and Non-Kerr black Holes

abstract:
  Embedded diagrams are drawn for investigating the black hole of Kerr and
non-Kerr metric. Kerr black holes are characterized by masses $M$ and spin
parameters $a$. Non-Kerr black holes also are characterized by the deformation
parameters $\epsilon$, which is related to shape of the black hole, in addition
to their masses and spins. In this paper, we investigate the behavior of
non-Kerr black holes compared with Kerr black holes in the parameter space of
($a$,$\epsilon$) using embedded diagrams. The event horizons and the naked
singularity of non-Kerr BHs are discussed in detail.


title:
Quantum Engineering of a Low-Entropy Gas of Heteronuclear Bosonic
  Molecules in an Optical Lattice

abstract:
  We demonstrate a generally applicable technique for mixing two-species
quantum degenerate bosonic samples in the presence of an optical lattice, and
we employ it to produce low-entropy samples of ultracold 87Rb133Cs Feshbach
molecules with a lattice filling fraction exceeding 30%. Starting from two
spatially separated Bose-Einstein condensates of Rb and Cs atoms, Rb-Cs atom
pairs are efficiently produced by using the superfluid-to-Mott insulator
quantum phase transition twice, first for the Cs sample, then for the Rb
sample, after nulling the Rb-Cs interaction at a Feshbach resonance's zero
crossing. We form molecules out of atom pairs and characterize the mixing
process in terms of sample overlap and mixing speed. The dense and ultracold
sample of more than 5000 RbCs molecules is an ideal starting point for
experiments in the context of quantum many-body physics with long-range dipolar
interactions.


title:
Emergent Electromagnetic Induction and Adiabatic Charge Pumping in Weyl
  Semimetals

abstract:
  The photovoltaic effect in a Weyl semimetal due to the adiabatic quantum
phase is studied. We particularly focus on the case in which an external ac
electric field is applied to the semimetal. In this setup, we show that a
photocurrent is induced by the ac electric field. By considering a generalized
Weyl Hamiltonian with nonlinear terms, it is shown that the photocurrent is
induced by circularly, rather than linearly, polarized light. This photovoltaic
current can be understood as an emergent electromagnetic induction in the
momentum space; the Weyl node is a magnetic monopole in the momentum space, of
which the electric field is induced by the circular motion. This result is
distinct from conventional photovoltaic effects, and potentially useful for
experimentally identifying Weyl semimetals in chiral crystals.


title:
Inelastic neutron scattering investigations of an anisotropic
  hybridization gap in the Kondo insulators: CeT2Al10 (T=Fe, Ru and Os)

abstract:
  The recent discovery of topological Kondo insulating behaviour in strongly
correlated electron systems has generated considerable interest in Kondo
insulators both experimentally and theoretically. The Kondo semiconductors
CeT2Al10 (T=Fe, Ru and Os) possessing a c-f hybridization gap have received
considerable attention recently because of the unexpected high magnetic
ordering temperature of CeRu2Al10 (TN=27 K) and CeOs2Al10 (TN=28.5 K) and the
Kondo insulating behaviour observed in the valence fluctuating compound
CeFe2Al10 with a paramagnetic ground state down to 50 mK. We are investigating
this family of compounds, both in polycrystalline and single crystal form,
using inelastic neutron scattering to understand the role of anisotropic c-f
hybridization on the spin gap formation as well as on their magnetic
properties. We have observed a clear sign of a spin gap in all three compounds
from our polycrystalline study as well as the existence of a spin gap above the
magnetic ordering temperature in T=Ru and Os. Our inelastic neutron scattering
studies on single crystals of CeRu2Al10 and CeOs2Al10 revealed dispersive
gapped spin wave excitations below TN. Analysis of the spin wave spectrum
reveals the presence of strong anisotropic exchange, along the c-axis (or
z-axis) stronger than in the ab-plane. These anisotropic exchange interactions
force the magnetic moment to align along the c-axis, competing with the single
ion crystal field anisotropy, which prefers moments along the a-axis. In the
paramagnetic state (below 50 K) of the Kondo insulator CeFe2Al10, we have also
observed dispersive gapped magnetic excitations which transform into
quasi-elastic scattering on heating to 100 K. We will discuss the origin of the
anisotropic hybridization gap in CeFe2Al10 based on theoretical models of
heavy-fermion semiconductors.


title: An Interesting Gadget for Chain Pair Simplification

abstract:
  In this paper we present an interesting gadget based on the chain pair
simplification problem under the discrete Fr\'echet distance (CPS-3F), which
allows the construction of arbitrarily long paths that must be chosen in the
simplification of the two curves. A pseudopolynomial time reduction from set
partition is given as an example. For clarification, CPS-3F was recently shown
to be in \textbf{P}, and the reduction is merely to show how the gadget works.


title:
User Load Analysis and Pilot Sequence Design for Multi-Cell Massive MIMO
  Networks

abstract:
  We propose a novel algorithm to design user load-achieving pilot sequences
that mitigate pilot contamination in multi-cell massive multiple-input
multiple-output (MIMO) networks. To this end, we first derive expressions for
the user load and the load region of the network considering both small-scale
and large-scale propagation effects. We then develop the pilot sequence
algorithm for multi-cell massive MIMO networks as per the rules of generalized
Welch bound equality design. Notably, we find that our algorithm and the
corresponding downlink power allocation ensure that the user load is achieved
when the signal-to-interference-plus-noise ratio (SINR) requirements for the
users lie within the load region. Furthermore, we demonstrate the performance
advantage of our proposed design relative to the existing designs, in terms of
a larger load region and a higher maximum permitted SINR. Finally, we show that
our proposed design can satisfy the pre-defined SINR requirements for users
with a finite number of antennas at the base station (BS), while the existing
designs cannot satisfy the same requirements even with an infinite number of
antennas at the BS.


title: Novel Graph Processor Architecture, Prototype System, and Results

abstract:
  Graph algorithms are increasingly used in applications that exploit large
databases. However, conventional processor architectures are inadequate for
handling the throughput and memory requirements of graph computation. Lincoln
Laboratory's graph-processor architecture represents a rethinking of parallel
architectures for graph problems. Our processor utilizes innovations that
include a sparse matrix-based graph instruction set, a cacheless memory system,
accelerator-based architecture, a systolic sorter, high-bandwidth
multi-dimensional toroidal communication network, and randomized
communications. A field-programmable gate array (FPGA) prototype of the new
graph processor has been developed with significant performance enhancement
over conventional processors in graph computational throughput.


title:
How to Characterize Thermal Transport Capability of 2D Materials Fairly?
  - Sheet Thermal Conductance and the Choice of Thickness

abstract:
  Ever since the discovery of the record-high thermal conductivity of single
layer graphene, thermal transport capability of monolayer 2D materials has been
under constant spotlight. Since thermal conductivity is an intensive property
for 3D materials and the thickness of 2D materials is not well defined,
different definitions of thickness in literature have led to ambiguity towards
predicting thermal conductivity values and thus in understanding the heat
transfer capability of different monolayer 2D materials. We argue that if
conventional definition of thermal conductivity should be used as the quantity
to compare the heat transfer capability of various monolayer 2D materials, then
the same thickness should be used. Alternatively, to circumvent the problem of
ambiguous thickness completely, we also suggest that a "sheet thermal
conductance" to be defined as an intensive 2D material property when
characterizing the heat transfer capability of 2D materials. When converting
literature thermal conductivity values of monolayer materials to this new
property, some new features that were not displayed when using different
thicknesses show up.


title: LLMapReduce: Multi-Level Map-Reduce for High Performance Data Analysis

abstract:
  The map-reduce parallel programming model has become extremely popular in the
big data community. Many big data workloads can benefit from the enhanced
performance offered by supercomputers. LLMapReduce provides the familiar
map-reduce parallel programming model to big data users running on a
supercomputer. LLMapReduce dramatically simplifies map-reduce programming by
providing simple parallel programming capability in one line of code.
LLMapReduce supports all programming languages and many schedulers. LLMapReduce
can work with any application without the need to modify the application.
Furthermore, LLMapReduce can overcome scaling limits in the map-reduce parallel
programming model via options that allow the user to switch to the more
efficient single-program-multiple-data (SPMD) parallel programming model. These
features allow users to reduce the computational overhead by more than 10x
compared to standard map-reduce for certain applications. LLMapReduce is widely
used by hundreds of users at MIT. Currently LLMapReduce works with several
schedulers such as SLURM, Grid Engine and LSF.


title: Scheduler Technologies in Support of High Performance Data Analysis

abstract:
  Job schedulers are a key component of scalable computing infrastructures.
They orchestrate all of the work executed on the computing infrastructure and
directly impact the effectiveness of the system. Recently, job workloads have
diversified from long-running, synchronously-parallel simulations to include
short-duration, independently parallel high performance data analysis (HPDA)
jobs. Each of these job types requires different features and scheduler tuning
to run efficiently. A number of schedulers have been developed to address both
job workload and computing system heterogeneity. High performance computing
(HPC) schedulers were designed to schedule large-scale scientific modeling and
simulations on supercomputers. Big Data schedulers were designed to schedule
data processing and analytic jobs on clusters. This paper compares and
contrasts the features of HPC and Big Data schedulers with a focus on
accommodating both scientific computing and high performance data analytic
workloads. Job latency is critical for the efficient utilization of scalable
computing infrastructures, and this paper presents the results of job launch
benchmarking of several current schedulers: Slurm, Son of Grid Engine, Mesos,
and Yarn. We find that all of these schedulers have low utilization for
short-running jobs. Furthermore, employing multilevel scheduling significantly
improves the utilization across all schedulers.


title: On two arithmetic theta lifts

abstract:
  Our aim is to clarify the relationship between Kudla's and Bruinier's Green
functions attached to special cycles on Shimura varieties of orthogonal and
unitary type. These functions play a key role in the arithmetic geometry of the
special cycles in the context of Kudla's program.
  In particular, we show that the generating series obtained by taking the
differences of the two families of Green functions is a modular form with
trivial holomorphic projection. Along the way, we construct a section of the
Maass lowering operator for moderate growth modular forms valued in the Weil
representation using a regularized theta lift, which may be of independent
interest. We also consider arithmetic-geometric applications to integral models
of U(n, 1) Shimura varieties.
  Each family of Green functions gives rise to a formal arithmetic theta
function, valued in an arithmetic Chow group, that is conjectured to be
modular; our main result is the modularity of the difference of the two
arithmetic theta functions. Finally, we relate the arithmetic heights of the
special cycles to special derivatives of Eisenstein series, as predicted by
Kudla's conjecture, and describe a refinement of a theorem of
Bruinier-Howard-Yang on arithmetic intersections against CM points.


title:
Resolution to the firewall paradox: The black hole information paradox
  and highly squeezed interior quantum fluctuations

abstract:
  Almheiri, Marolf, Polchinski, and Sully argued that, for a consistent black
hole evaporation process, the horizon of a sufficiently old black hole should
be replaced by a "firewall" at which an infalling observer burns up, which
obviously leads to the violation of the equivalence principle. We propose that
once the infalling partner of an outgoing Hawking particle approaches a black
hole singularity, it experiences decoherence and the loss of its entanglement
with the outgoing Hawking particle. This implies we would no longer need
firewalls to avoid the black hole information paradox.


title: Second Stop and Sbottom Searches with a Stealth Stop

abstract:
  The top squarks (stops) may be the most wanted particles after the Higgs
boson discovery. The searches for the lightest stop have put strong constraints
on its mass. However, there is still a search gap in the low mass region if the
spectrum of the stop and the lightest neutralino is compressed. In that case,
it may be easier to look for the second stop since naturalness requires both
stops to be close to the weak scale. The current experimental searches for the
second stop are based on the simplified model approach with the decay modes
$\tilde{t}_2 \to \tilde{t}_1 Z$ and $\tilde{t}_2 \to \tilde{t}_1 h$. However,
in a realistic supersymmetric spectrum there is always a sbottom lighter than
the second stop, hence the decay patterns are usually more complicated than the
simplified model assumptions. In particular, there are often large branching
ratios of the decays $\tilde{t}_2 \to \tilde{b}_1 W$ and $\tilde{b}_1 \to
\tilde{t}_1 W$ as long as they are open. The decay chains can be even more
complex if there are intermediate states of additional charginos and
neutralinos in the decays. By studying several MSSM benchmark models at the 14
TeV LHC, we point out the importance of the multi-$W$ final states in the
second stop and the sbottom searches, such as the same-sign dilepton and
multilepton signals, aside from the traditional search modes. The observed
same-sign dilepton excesses at LHC Run 1 and Run 2 may be explained by some of
our benchmark models. We also suggest that the vector boson tagging and a new
kinematic variable may help to suppress the backgrounds and increase the signal
significance for some search channels. Due to the complex decay patterns and
lack of the dominant decay channels, the best reaches likely require a
combination of various search channels at the LHC for the second stop and the
lightest sbottom.


title:
The Symmetry of Current of the Coherent State From the View of O(3)
  sigma-model

abstract:
  In this paper, we apply the reduced density trajectory, phi-mapping
topological current theory and Ginzberg-Landau model to study the current of
the coherent state. We give the new expression of the current of the coherent
state. Based on this expression, the symmetry of the coherence is studied. We
find that the current of the coherent state corresponds to the supercurrent of
two-condensate system. The partial wave functions of the coherence carry new
charges and their interaction is mediated by new U(1) gauge potential.


title:
Effect of nematic order on the low-energy spin fluctuations in detwinned
  BaFe$_{1.935}$Ni$_{0.065}$As$_2$

abstract:
  The origin of nematic order remains one of the major debates in iron-based
superconductors. In theories based on spin nematicity, one major prediction is
that the spin-spin correlation length at (0,$\pi$) should decrease with
decreasing temperature below the structural transition temperature $T_s$. Here
we report inelastic neutron scattering studies on the low-energy spin
fluctuations in BaFe$_{1.935}$Ni$_{0.065}$As$_2$ under uniaxial pressure. Both
intensity and spin-spin correlation start to show anisotropic behavior at high
temperature, while the reduction of the spin-spin correlation length at
(0,$\pi$) happens just below $T_s$, suggesting strong effect of nematic order
on low-energy spin fluctuations. Our results favor the idea that treats the
spin degree of freedom as the driving force of the electronic nematic order.


title: Castelnuovo-Mumford Regularity and GV-Sheaves on Irregular Varieties

abstract:
  Inspired by Beauville's recent construction of Ulrich sheaves on abelian
surfaces, we pose the question of whether a torsion-free sheaf on a polarized
smooth projective variety with Castelnuovo-Mumford regularity 1 is a GV
(generic vanishing) sheaf, and present evidence that this question is governed
by the positivity of cycles on generalized Brill-Noether loci. We prove that it
has an affirmative answer for natural polarizations on many well-known
irregular surfaces, as well as some polarizations on ruled threefolds over a
curve.


title: Cosmological relaxation and high scale inflation

abstract:
  We study whether the relaxion mechanism solves the Higgs hierarchy problem
against a high scale inflation or a high reheating temperature. To accomplish
the mechanism, we consider the scenario that the Higgs vacuum expectation value
is determined after inflation. We take into account the effects of the Hubble
induced mass and thermal one in the dynamics of the relaxion.


title: Heavy axion in asymptotically safe QCD

abstract:
  Assuming QCD exhibits an interacting fixed-point behaviour in the ultraviolet
regime, I argue that the axion can be substantially heavier than in the
conventional case of asymptotically free QCD due to the enhanced contribution
of small size instantons to its mass.


title:
A small normal generating set for the handlebody subgroup of the Torelli
  group

abstract:
  We prove that the handlebody subgroup of the Torelli group of an orientable
surface is generated by genus one BP-maps. As an application, we give a normal
generating set for the handlebody subgroup of the level $d$ mapping class group
of an orientable surface.


title:
Canonical duality approach in the approximation of optimal Monge mass
  transfer mapping

abstract:
  This paper mainly addresses the Monge mass transfer problem in the 1-D case.
Through an ingenious approximation mechanism, one transforms the Monge problem
into a sequence of minimization problems, which can be converted into a
sequence of nonlinear differential equations with constraints by variational
method. The existence and uniqueness of the solution for each equation can be
demonstrated by applying the canonical duality method. Moreover, the duality
method gives a sequence of perfect dual maximization problems. In the final
analysis, one constructs the approximation of optimal mapping for the Monge
problem according to the theoretical results.


title: Matrix pentagons

abstract:
  The Operator Product Expansion for null polygonal Wilson loop in planar
maximally supersymmetric Yang-Mills theory runs systematically in terms of
multiparticle pentagon transitions which encode the physics of excitations
propagating on the color flux tube ending on the sides of the four-dimensional
contour. Their dynamics was unravelled in the past several years and culminated
in a complete description of pentagons as an exact function of the 't Hooft
coupling. In this paper we provide a solution for the last building block in
this program, the SU(4) matrix structure arising from internal symmetry indices
of scalars and fermions. This is achieved by a recursive solution of the Mirror
and Watson equations obeyed by the so-called singlet pentagons and fixing the
form of the twisted component in their tensor decomposition. The non-singlet,
or charged, pentagons are deduced from these by a limiting procedure.


title: Syntax-based Attention Model for Natural Language Inference

abstract:
  Introducing attentional mechanism in neural network is a powerful concept,
and has achieved impressive results in many natural language processing tasks.
However, most of the existing models impose attentional distribution on a flat
topology, namely the entire input representation sequence. Clearly, any
well-formed sentence has its accompanying syntactic tree structure, which is a
much rich topology. Applying attention to such topology not only exploits the
underlying syntax, but also makes attention more interpretable. In this paper,
we explore this direction in the context of natural language inference. The
results demonstrate its efficacy. We also perform extensive qualitative
analysis, deriving insights and intuitions of why and how our model works.


title:
An approximation method for the optimization of $p$-th moment of
  $\mathbb{R}^n$-valued random variable

abstract:
  This paper mainly addresses the optimization of $p$-th moment of
$\mathbb{R}^n$-valued random variable. Through an ingenious approximation
mechanism, one transforms the maximization problem into a sequence of
minimization problems, which can be converted into a sequence of nonlinear
differential equations with constraints by variational approach. The existence
and uniqueness of the solution for each equation can be demonstrated by
applying the canonical duality method. Moreover, the dual transformation gives
a sequence of perfect dual maximization problems. In the final analysis, one
constructs the approximation of the probability density function accordingly.


title:
Tuning of the Charged Hadrons Multiplicities for Deep Inelastic
  Interactions in NEUT

abstract:
  We describe a procedure to tune the charged hadron multiplicities for deep
inelastic events produced by the NEUT neutrino interaction generator. This
tuning uses a model based on Koba-Nielsen-Olesen scaling, whose parameters are
obtained by fitting multiplicity data from deuterium bubble chamber
experiments. After tuning, the multiplicities of the events generated by NEUT
are found to be in good agreement with the measurements from the bubble chamber
experiments.


title:
Relations among pionic decays of spin-1 mesons from an SU(4)$\times$U(1)
  emergent symmetry in QCD

abstract:
  Motivated by recent results by lattice analysis, we assume that the spin-1
mesons of $\left( \rho, \omega, a_1, \rho', \omega', b_1, f_1, h_1\right)$ make
a representation of $\mathbf{16}$ of U(4) emergent symmetry in two-flavor QCD
when the chiral symmetry is not broken. We study the decay properties of the
spin-1 mesons by using a chiral model with an SU(4)$\times$U(1) hidden local
symmetry. We first show that, since the SU(4) symmetry is spontaneously broken
together with the chiral symmetry, each coupling of the interaction among one
pion and two spin-1 mesons is proportional to the mass difference of the
relevant spin-1 mesons similarly to the Goldberger-Treiman relation. In
addition, some of one-pion couplings are related with each other by the SU(4)
symmetry. We further show that there is a relation among the mass of $\rho'$
meson, the $\rho'\pi\pi$ coupling and the $\rho'$-photon mixing strength as
well as the Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin relation for the $\rho$
meson. From the relations, we give numerical predictions such as ratios of the
spin-1 meson decay widths, which are compared with future experiments for
testing the existence of the U(4) emergent symmetry.


title: Automated Prediction of Temporal Relations

abstract:
  Background: There has been growing research interest in automated answering
of questions or generation of summary of free form text such as news article.
In order to implement this task, the computer should be able to identify the
sequence of events, duration of events, time at which event occurred and the
relationship type between event pairs, time pairs or event-time pairs. Specific
Problem: It is important to accurately identify the relationship type between
combinations of event and time before the temporal ordering of events can be
defined. The machine learning approach taken in Mani et. al (2006) provides an
accuracy of only 62.5 on the baseline data from TimeBank. The researchers used
maximum entropy classifier in their methodology. TimeML uses the TLINK
annotation to tag a relationship type between events and time. The time
complexity is quadratic when it comes to tagging documents with TLINK using
human annotation. This research proposes using decision tree and parsing to
improve the relationship type tagging. This research attempts to solve the gaps
in human annotation by automating the task of relationship type tagging in an
attempt to improve the accuracy of event and time relationship in annotated
documents. Scope information: The documents from the domain of news will be
used. The tagging will be performed within the same document and not across
documents. The relationship types will be identified only for a pair of event
and time and not a chain of events. The research focuses on documents tagged
using the TimeML specification which contains tags such as EVENT, TLINK, and
TIMEX. Each tag has attributes such as identifier, relation, POS, time etc.


title:
LZIFU: an emission-line fitting toolkit for integral field spectroscopy
  data

abstract:
  We present LZIFU (LaZy-IFU), an IDL toolkit for fitting multiple emission
lines simultaneously in integral field spectroscopy (IFS) data. LZIFU is useful
for the investigation of the dynamical, physical and chemical properties of gas
in galaxies. LZIFU has already been applied to many world-class IFS instruments
and large IFS surveys, including the Wide Field Spectrograph, the new Multi
Unit Spectroscopic Explorer (MUSE), the Calar Alto Legacy Integral Field Area
(CALIFA) survey, the Sydney-Australian-astronomical-observatory Multi-object
Integral-field spectrograph (SAMI) Galaxy Survey. Here we describe in detail
the structure of the toolkit, and how the line fluxes and flux uncertainties
are determined, including the possibility of having multiple distinct kinematic
components. We quantify the performance of LZIFU, demonstrating its accuracy
and robustness. We also show examples of applying LZIFU to CALIFA and SAMI data
to construct emission line and kinematic maps, and investigate complex, skewed
line profiles presented in IFS data. The code is made available to the
astronomy community through github. LZIFU will be further developed over time
to other IFS instruments, and to provide even more accurate line and
uncertainty estimates.


title: Schwarzschild Solution from WTDiff Gravity

abstract:
  We study classical solutions in the Weyl-transverse (WTDiff) gravity. The
WTDiff gravity is invariant under both the local Weyl (conformal)
transformation and the volume preserving diffeormorphisms (transverse
diffeomorphisms) and is known to be equivalent to general relativity at least
at the classical level. In particular, we find that in a general space-time
dimension, the Schwarzschild metric is a classical solution in the WTDiff
gravity when it is expressed in the Cartesian coordinate system.


title: Leaky Integrate-and-Fire Neuron under Poisson Stimulation

abstract:
  We consider a single Leaky integrate-and-fire neuron stimulated with Poisson
process. We develop a method, which allows one to obtain the first passage time
probability density function without any additional approximations.


title:
On Stochastic Comparisons of Order Statistics from Heterogeneous
  Exponential Samples

abstract:
  We show that the $k$th order statistic from a heterogeneous sample of $n\geq
k$ exponential random variables is larger than that from a homogeneous
exponential sample in the sense of star ordering, as conjectured by Xu and
Balakrishnan (2012). As a consequence, we establish hazard rate ordering for
order statistics between heterogeneous and homogeneous exponential samples,
resolving an open problem of P\v{a}lt\v{a}nea (2008). Extensions to general
spacings are also presented.


title:
Estimating Causal Peer Influence in Homophilous Social Networks by
  Inferring Latent Locations

abstract:
  Social influence cannot be identified from purely observational data on
social networks, because such influence is generically confounded with latent
homophily, i.e., with a node's network partners being informative about the
node's attributes and therefore its behavior. If the network grows according to
either a latent community (stochastic block) model, or a continuous latent
space model, then latent homophilous attributes can be consistently estimated
from the global pattern of social ties. We show that, for common versions of
those two network models, these estimates are so informative that controlling
for estimated attributes allows for asymptotically unbiased and consistent
estimation of social-influence effects in linear models. In particular, the
bias shrinks at a rate which directly reflects how much information the network
provides about the latent attributes. These are the first results on the
consistent non-experimental estimation of social-influence effects in the
presence of latent homophily, and we discuss the prospects for generalizing
them.


title:
Entangling Higgs production associated with a single top and a top-quark
  pair in the presence of anomalous top-Yukawa coupling

abstract:
  The ATLAS and CMS collaborations observed a mild excess in the associated
Higgs production with a top-quark pair ($t\bar t h$) and reported the signal
strengths of $ \mu_{tth}^{\rm ATLAS}=1.81\pm 0.80$ and $\mu_{tth}^{\rm
CMS}=2.75\pm 0.99 $ based on the data collected at $\sqrt{s}$= 7 and 8 TeV.
Although, at the current stage, there is no obvious indication whether the
excess is real or due to statistical fluctuations, here we perform a case study
of this mild excess by exploiting the strong entanglement between the
associated Higgs production with a single top quark ($thX$) and $t\bar t h$
production in the presence of anomalous top-Yukawa coupling. As well known,
$t\bar t h$ production only depends on the absolute value of the top-Yukawa
coupling. Meanwhile, in $thX$ production, this degeneracy is lifted through the
strong interference between the two main contributions which are proportional
to the top-Yukawa and the gauge-Higgs couplings, respectively. Especially, when
the relative sign of the top-Yukawa coupling with respect to the gauge-Higgs
coupling is reversed, the $thX$ cross section can be enhanced by more than one
order of magnitude. We perform a detailed study of the influence of $thX$
production on $t\bar{t}h $ production in the presence of the anomalous
top-Yukawa coupling and point out that it is crucial to include $thX$
production in the analysis of the $t\bar t h$ data to pin down the sign and the
size of the top-Yukawa coupling in future. While assuming the Standard Model
(SM) value for the gauge-Higgs coupling, we vary the top-Yukawa coupling within
the range allowed by the current LHC Higgs data. We consider the Higgs decay
modes into multileptons, $b\bar b$ and $\gamma\gamma$ putting a particular
emphasis on the same sign dilepton events. We also discuss ...


title: Spin-orbit interaction in relativistic nuclear structure models

abstract:
  Relativistic self-consistent mean-field (SCMF) models naturally account for
the coupling of the nucleon spin to its orbital motion, whereas
non-relativistic SCMF methods necessitate a phenomenological ansatz for the
effective spin-orbit potential. Recent experimental studies aim to explore the
isospin properties of the effective spin-orbit interaction in nuclei. SCMF
models are very useful in the interpretation of the corresponding data, however
standard relativistic mean-field and non-relativistic Hartree-Fock models use
effective spin-orbit potentials with different isovector properties, mainly
because exchange contributions are not treated explicitly in the former. The
impact of exchange terms on the effective spin-orbit potential in relativistic
mean-field models is analysed, and it is shown that it leads to an isovector
structure similar to the one used in standard non-relativistic Hartree-Fock.
Data on the isospin dependence of spin-orbit splittings in spherical nuclei
could be used to constrain the isovector-scalar channel of relativistic
mean-field models. The reproduction of the empirical kink in the isotope shifts
of even Pb nuclei by relativistic effective interactions points to the
occurrence of pseudospin symmetry in the single-neutron spectra in these
nuclei.


title: Ring correlations in random networks

abstract:
  We examine the correlations between rings in random network glasses in two
dimensions as a function of their separation. Initially, we use the topological
separation (measured by the number of intervening rings), but this leads to
pseudo-long-range correlations due to a lack of topological charge neutrality
in the shells surrounding a central ring. This effect is associated with the
non-circular nature of the shells. It is, therefore, necessary to use the
geometrical distance between ring centers. Hence we find a generalization of
the Aboav-Weaire law out to larger distances, with the correlations between
rings decaying away when two rings are more than about 3 rings apart.


title:
Second-order Optimality Conditions by Generalized Derivatives and
  Applications in Hilbert Spaces

abstract:
  In this paper, in terms of three types of generalized second-order
derivatives of a nonsmooth function, we mainly study the corresponding
second-order optimality conditions in a Hilbert space and prove the equivalence
among these optimality conditions for paraconcave functions. As applications,
we use these second-order optimality conditions to study strict local
minimizers of order two and provide sufficient and/or necessary conditions for
ensuring the local minimizer. This work extends and generalizes the study on
second-order optimality conditions from the finite-dimensional space to the
Hilbert space.


title:
Mapping of Electronic Band Gap along the Axis of Single InAs/InSbxAs1-x
  Heterostructured Nanowire

abstract:
  We report the graded electronic band gap along the axis of individual
heterostructured WZ-ZB InAs/InSb0.12As0.88 nanowires. Resonance Raman imaging
has been exploited to map the axial variation in the second excitation gap
energy (E1) at the high symmetry point (L point) of the Brillouin zone. We
relate the origin of the observed evolution of the gap energy to the fine
tuning of the alloy composition from the tip towards the interface of the
nanowire. The electronic band structures of InAs, InSb and InSbxAs1-x alloy
systems at x=0.125, 0.25, 0.50, 0.75 and 0.875, using all electron density
functional theory code Wien2k, are reported. The measured band gap along the
axis of the InAs/InSb0.12As0.88 nanowire is correlated with the calculated gap
energy at the A point and the L point of the Brillouin zone for InAs and
InSb0.125As0.875, respectively. We draw a one-to-one correspondence between the
variation of the E1 gap and the fundamental E0 gap in the calculated electronic
band structure and propose the graded fundamental gap energy across the axis of
the nanowire.


title:
Application of sampling theory in modeling of continuum processes:
  photoionization cross-sections of atoms

abstract:
  We describe a method for the calculation of photoionization cross-sections
using square-integrable amplitudes obtained from the diagonalization of
finite-basis set representations of the electronic Hamiltonian. Three examples
are considered: a model example in which the final state is a free particle,
the hydrogen atom and neutral atomic sodium. The method exploits the
Whittaker-Shannon-Kotel'nikov sampling theorem, which is widely used in digital
signal sampling and reconstruction. The approach reproduces known data with
very good accuracy and converges to the exact solution with increase of the
basis set size.


title:
Parity-violating $\pi NN$ coupling constant from the flavor-conserving
  effective weak chiral Lagrangian

abstract:
  We investigate the parity-violating pion-nucleon-nucleon coupling constant
$h^1_{\pi NN}$, based on the chiral quark-soliton model. We employ an effective
weak Hamiltonian that takes into account the next-to-leading order corrections
from QCD to the weak interactions at the quark level. Using the gradient
expansion, we derive the leading-order effective weak chiral Lagrangian with
the low-energy constants determined. The effective weak chiral Lagrangian is
incorporated in the chiral quark-soliton model to calculate the
parity-violating $\pi NN$ constant $h^1_{\pi NN}$. We obtain a value of about
$10^{-7}$ at the leading order. The corrections from the next-to-leading order
reduce the leading order result by about 20~\%.


title: Almost universal ternary sums of polygonal numbers

abstract:
  For a natural number $m$, generalized $m$-gonal numbers are those numbers of
the form $p_m(x)=\frac{(m-2)x^2-(m-4)x}{2}$ with $x\in \mathbb Z$. In this
paper we establish conditions on $m$ for which the ternary sum
$p_m(x)+p_m(y)+p_m(z)$ is almost universal.


title: Yb fiber amplifier at 972.5 nm with frequency quadrupling to 243.1 nm

abstract:
  We demonstrate a continuous-wave ytterbium-doped fiber amplifier which
produces 6.3 W at a wavelength of 972.5 nm. We frequency quadruple this source
in two resonant doubling stages to produce 530 mW at 243.1 nm. Radiation at
this wavelength is required to excite the 1S-2S transition in atomic hydrogen
and could therefore find application in experimental studies of hydrogen and
anti-hydrogen.


title:
Collective excitations of dynamic Fermi surface deformations in
  BaFe$_2$(As$_{0.5}$P$_{0.5}$)$_2$

abstract:
  We use electronic Raman scattering to study the low-energy excitations in
BaFe$_2$(As$_{0.5}$P$_{0.5}$)$_2$ ($T_c \approx 16$ K) samples. In addition to
a superconducting pair breaking peak (2$\Delta=6.7$ meV) in the A$_{1g}$
channel with a linear tail towards zero energy, suggesting a nodal gap
structure, we detect spectral features associated to Pomeranchuk oscillations
in the A$_{1g}$, B$_{1g}$ and B$_{2g}$ channels. We argue that the small Fermi
energy of the system is an essential condition for these Pomeranchuk
oscillations to be underdamped. The Pomeranchuk oscillations have the same
frequencies in the B$_{1g}$ and B$_{2g}$ channels, which we explain by the
mixing of these symmetries resulting from the removal of the $\sigma_v$ and
$\sigma_v$ symmetry planes due to a large As/P disorder. Interestingly, we show
that the temperature at which the peaks corresponding to the Pomeranchuk
oscillations get underdamped is consistent with the non-Fermi liquid to Femi
liquid crossover determined by transport, suggesting that the Pomeranchuk
instability plays an important role in the low-energy physics of the Fe-based
superconductors.


title: Invariant theory of relatively free right-symmetric and Novikov algebras

abstract:
  Algebras with the polynomial identity (x,y,z)=(x,z,y), where
(x,y,z)=x(yz)-(xy)z is the associator, are called right-symmetric. Novikov
algebras are right-symmetric algebras satisfying additionally the polynomial
identity x(yz)=y(xz). We consider the d-generated free right-symmetric algebra
F(R) and the free Novikov algebra F(N) over a filed K of characteristic 0. The
general linear group GL(K,d) with its canonical action on the d-dimensional
vector space with basis the generators of F(R) and F(N) acts on F(R) and F(N)
as a group of linear automorphisms. For a subgroup G of GL(K,d) we study the
algebras of G-invariants in F(R) and F(N). For a large class of groups G we
show that these algebras of invariants are never finitely generated. The same
result holds for any subvariety of the variety R of right-symmetric algebras
which contains the subvariety L of left-nilpotent of class 3 algebras in R.


title:
Nonlocal discrete continuity and invariant currents in locally symmetric
  effective Schr\"odinger arrays

abstract:
  We develop a formalism relating nonlocal current continuity to spatial
symmetries of subparts in discrete Schr\"odinger systems. Breaking of such
local symmetries hereby generates sources or sinks for the associated nonlocal
currents. The framework is applied to locally inversion-(time-) and
translation-(time-) symmetric one-dimensional photonic waveguide arrays with
Hermitian or non-Hermitian effective tight-binding Hamiltonians. For stationary
states the nonlocal currents become translationally invariant within symmetric
domains, exposing different types of local symmetry. They are further employed
to derive a mapping between wave amplitudes of symmetry-related sites,
generalizing also the global Bloch and parity mapping to local symmetry in
discrete systems. In scattering setups, perfectly transmitting states are
characterized by aligned invariant currents in attached symmetry domains, whose
vanishing signifies a correspondingly symmetric density. For periodically
driven arrays, the invariance of the nonlocal currents is retained on period
average for quasi-energy eigenstates. The proposed theory of symmetry-induced
continuity and local invariants may contribute to the understanding of wave
structure and response in systems with localized spatial order.


title: Magnetogenesis in bouncing cosmology

abstract:
  We consider the process of magnetogenesis in the context of nonsingular
bounce cosmology. We show that large primordial magnetic fields can be
generated during contraction without encountering strong coupling and
backreaction issues. The fields may seed large-scale magnetic fields with
observationally interesting strengths. This result leads to a theoretical
constraint on the relation of the energy scale of the bounce cosmology to the
number of effective e-folding of the contracting phase in the case of scale
invariance for the power spectrum of primordial magnetic fields. We show that
this constraint can be satisfied in a sizable region of the parameter space for
the nonsingular bounce cosmology.


title:
Blow-up of a hyperbolic equation of viscoelasticity with supercritical
  nonlinearities

abstract:
  We investigate a hyperbolic PDE, modeling wave propagation in viscoelastic
media, under the influence of a linear memory term of Boltzmann type, and a
nonlinear damping modeling friction, as well as an energy-amplifying
supercritical nonlinear source: \begin{align*} \begin{cases} u_{tt}- k(0)
\Delta u - \int_0^{\infty} k'(s) \Delta u(t-s) ds + |u_t|^{m-1}u_t=|u|^{p-1}u,
\;\;\;\;\; \Omega \times (0,T), \\ u(x,t)=u_0(x,t), \quad \text{ in } \Omega
\times (-\infty,0], \end{cases} \end{align*} where $\Omega$ is a bounded domain
in $\mathbb R^3$ with a Dirichl\'et boundary condition. The relaxation kernel
$k$ is monotone decreasing and $k(\infty)=1$. We study blow-up of solutions
when the source is stronger than dissipations, i.e., $p>
\max\{m,\sqrt{k(0)}\}$, under two different scenarios: first, the total energy
is negative, and the second, the total energy is positive with sufficiently
large quadratic energy. This manuscript is a follow-up work of the paper [30]
in which Hadamard well-posedness of this equation has been established in the
finite energy space. The model under consideration features a supercritical
source and a linear memory that accounts for the full past history as time goes
to $-\infty$, which is distinct from other relevant models studied in the
literature which usually involve subcritical sources and a finite-time memory.


title: On the scaling methods by Pinchuk and Frankel

abstract:
  The main purpose of this paper is to study two scaling methods developed
respectively by Pinchuk and Frankel. We introduce first a continuously-varying
global coordinate system, and give an alternative proof to the convergence of
Pinchuk's scaling sequence (and of our modification) on bounded domains with
finite type boundaries in $\mathbb{C}^2$. Using this, we discuss the
modification of the Frankel scaling sequence on nonconvex domains. We also
observe that two modified scalings are equivalent.


title:
Shared Energy Storage Management for Renewable Energy Integration in
  Smart Grid

abstract:
  Energy storage systems (ESSs) are essential components of the future smart
grid to smooth out the fluctuating output of renewable energy generators.
However, installing large number of ESSs for individual energy consumers may
not be practically implementable, due to both the space limitation and high
investment cost. As a result, in this paper, we study the energy management
problem of multiple users with renewable energy sources and a single shared
ESS. To solve this problem, we propose an algorithm that jointly optimizes the
energy charged/discharged to/from the shared ESS given a profit coefficient set
that specifies the desired proportion of the total profit allocated to each
user, subject to practical constraints of the system. We conduct simulations
based on the real data from California, US, and show that the shared ESS can
potentially increase the total profit of all users by 10% over the case that
users own individual small-scale ESSs with no energy sharing.


title:
Nonlinear Bloch-waves and current states of exciton-polariton
  condensates

abstract:
  The formation of nonlinear Bloch states in open driven-dissipative system of
exciton-polaritons loaded into a weak-contrast 1D periodic lattice is studied
numerically and analytically. The condensate is described within the framework
of mean-field theory by the coupled equations for the order parameter and for
the density of incoherent excitons. The stationary nonlinear solutions having
the structure of Bloch waves are studied in detail. It is shown that there is a
bifurcation leading to the appearance of a family of essentially nonlinear
states. The special feature of these solutions is that its current does not
vanish when the quasi-momentum of the state approaches the values equal to the
half of the lattice constant. To explain the bifurcations found in numerical
simulations a simple perturbative approach is developed. The stability of the
nonlinear states is examined by linear spectral analysis and by direct
numerical simulations. An experimental scheme allowing the observation of the
discussed nonlinear current states is suggested and studied by numerical
simulations.


title:
Classification of Alzheimer's Disease Structural MRI Data by Deep
  Learning Convolutional Neural Networks

abstract:
  Recently, machine learning techniques especially predictive modeling and
pattern recognition in biomedical sciences from drug delivery system to medical
imaging has become one of the important methods which are assisting researchers
to have deeper understanding of entire issue and to solve complex medical
problems. Deep learning is a powerful machine learning algorithm in
classification while extracting low to high-level features. In this paper, we
used convolutional neural network to classify Alzheimer's brain from normal
healthy brain. The importance of classifying this kind of medical data is to
potentially develop a predict model or system in order to recognize the type
disease from normal subjects or to estimate the stage of the disease.
Classification of clinical data such as Alzheimer's disease has been always
challenging and most problematic part has been always selecting the most
discriminative features. Using Convolutional Neural Network (CNN) and the
famous architecture LeNet-5, we successfully classified structural MRI data of
Alzheimer's subjects from normal controls where the accuracy of test data on
trained data reached 98.84%. This experiment suggests us the shift and scale
invariant features extracted by CNN followed by deep learning classification is
most powerful method to distinguish clinical data from healthy data in fMRI.
This approach also enables us to expand our methodology to predict more
complicated systems.


title:
Tunable Schottky barrier and high responsivity in graphene/Si-nanotip
  optoelectronic device

abstract:
  We demonstrate tunable Schottky barrier height and record photo-responsivity
in a new-concept device made of a single-layer CVD graphene transferred onto a
matrix of nanotips patterned on n-type Si wafer. The original layout, where
nano-sized graphene/Si heterojunctions alternate to graphene areas exposed to
the electric field of the Si substrate, which acts both as diode cathode and
transistor gate, results in a two-terminal barristor with single-bias control
of the Schottky barrier. The nanotip patterning favors light absorption, and
the enhancement of the electric field at the tip apex improves photo-charge
separation and enables internal gain by impact ionization. These features
render the device a photodetector with responsivity (3 A/W for white LED light
at 3 mW/cm2 intensity) almost an order of magnitude higher than commercial
photodiodes. We extensively characterize the voltage and the temperature
dependence of the device parameters and prove that the multi-junction approach
does not add extra-inhomogeneity to the Schottky barrier height distribution.
This work represents a significant advance in the realization of graphene/Si
Schottky devices for optoelectronic applications.


title:
Maximal mutual correlation: an algebraic measure of correlations in
  bipartite quantum systems

abstract:
  We introduce an algebraic measure of correlations in bipartite quantum
systems. The proposed quantity, called maximal mutual correlation, provides the
information how much a given state differs from the product state of its
marginals. In contrast to the entanglement or quantum discord, maximal mutual
correlation can be non - zero for some classically correlated quantum states.


title: Sample Variance in Free Probability

abstract:
  Let $X_1, X_2,\dots, X_n$ denote i.i.d.~centered standard normal random
variables, then the law of the sample variance
$Q_n=\sum_{i=1}^n(X_i-\bar{X})^2$ is the $\chi^2$-distribution with $n-1$
degrees of freedom. It is an open problem in classical probability to
characterize all distributions with this property and in particular, whether it
characterizes the normal law. In this paper we present a solution of the free
analog of this question and show that the only distributions, whose free sample
variance is distributed according to a free $\chi^2$-distribution, are the
semicircle law and more generally so-called \emph{odd} laws, by which we mean
laws with vanishing higher order even cumulants. In the way of proof we derive
an explicit formula for the free cumulants of $Q_n$ which shows that indeed the
odd cumulants do not contribute and which exhibits an interesting connection to
the concept of $R$-cyclicity.


title:
3D Character Customization for Non-Professional Users in Handheld
  Augmented Reality

abstract:
  In gaming, customizing individual characters, can create personal bonds
between players and their characters. Hence, character customization is a
standard component in many games. While mobile Augmented Reality (AR) games
become popular, to date, no 3D character editor for AR games exists. We
investigate the feasibility of 3D character customization for smartphone-based
AR in an iterative design process.
  Specifically, we present findings from creating AR prototypes in a handheld
AR setting. In a first user study, we found that a tangible AR prototype
resulted in higher hedonistic measures than a camera-based approach. In a
follow up study, we compared the tangible AR prototype with a non-AR
touchscreen version for selection, scaling, translation and rotation tasks in a
3D character customization setting. The tangible AR version resulted in
significantly better results for stimulation and novelty measures than the
non-AR version. At the same time, it maintained a proficient level in pragmatic
measures such as accuracy and efficiency.


title:
Time-Inconsistent Mean-Field Stochastic LQ Problem: Open-Loop
  Time-Consistent Control

abstract:
  This paper is concerned with the open-loop time-consistent solution of
time-inconsistent mean-field stochastic linear-quadratic optimal control.
Different from standard stochastic linear-quadratic problems, both the system
matrices and the weighting matrices are dependent on the initial times, and the
conditional expectations of the control and state enter quadratically into the
cost functional. Such features will ruin Bellman's principle of optimality and
result in the time-inconsistency of the optimal control. Based on the dynamical
nature of the systems involved, a kind of open-loop time-consistent equilibrium
control is investigated in this paper. It is shown that the existence of
open-loop time-consistent equilibrium control for a fixed initial pair is
equivalent to the solvability of a set of forward-backward stochastic
difference equations with stationary conditions and convexity conditions. By
decoupling the forward-backward stochastic difference equations, necessary and
sufficient conditions in terms of linear difference equations and generalized
difference Riccati equations are given for the existence of open-loop
time-consistent equilibrium control with a fixed initial pair. Moreover, the
existence of open-loop time-consistent equilibrium control for all the initial
pairs is shown to be equivalent to the solvability of a set of coupled
constrained generalized difference Riccati equations and two sets of
constrained linear difference equations.


title: Pais-Uhlenbeck Oscillator and Negative Energies

abstract:
  We review the occurrence of negative energies in Pais-Uhlenbeck oscillator.
We point out that in the absence of interactions negative energies are not
problematic, neither in the classical nor in the quantized theory. However, in
the presence of interactions that couple positive and negative energy degrees
of freedom the system is unstable, unless the potential is bounded from bellow
and above. We review some approaches in the literature that attempt to avoid
the problem of negative energies in the Pais-Uhlenbeck oscillator.


title: Phonon-Josephson resonances in atomtronic circuits

abstract:
  We study the resonant excitation of sound modes from Josephson oscillations
in Bose-Einstein condensates. From the simulations for various setups using the
Gross-Pitaevskii mean-field equations and Josephson equations we observe
additional tunneling currents induced by resonant phonons. The proposed
experiment may be used for spectroscopy of phonons as well as other low-energy
collective excitations in Bose-Einstein condensates. We also argue that the
observed effect may mask the observation of Shapiro resonances if not carefully
controlled.


title:
Understanding the Plasmonics of Nanostructured Atomic Force Microscopy
  Tips

abstract:
  Structured metallic tips are increasingly important for optical
spectroscopies such as tip-enhanced Raman spectroscopy (TERS), with plasmonic
resonances frequently cited as a mechanism for electric field enhancement. We
probe the local optical response of sharp and spherical-tipped atomic force
microscopy (AFM) tips using a scanning hyperspectral imaging technique to
identify plasmonic behaviour. Localised surface plasmon resonances which
radiatively couple with far-field light are found only for spherical AFM tips,
with little response for sharp AFM tips, in agreement with numerical
simulations of the near-field response. The precise tip geometry is thus
crucial for plasmon-enhanced spectroscopies, and the typical sharp cones are
not preferred.


title: Evolution of binary seeds in collapsing protostellar gas clouds

abstract:
  We perform three dimensional smoothed particle hydrodynamics (SPH)
simulations of gas accretion onto the seeds of binary stars to investigate
their short-term evolution. Our simulation setup is more realistic compared to
the previous works by taking into account of dynamically evolving envelope with
non-uniform distribution of gas density and angular momentum of accreting flow.
Our initial condition includes a seed binary and a surrounding gas envelope,
modelling the phase of core collapse of gas cloud when the fragmentation has
already occurred. We assume that the seed binary has no eccentricity and no
growth by gas accretion. The envelope is assumed to be an isothermal gas with
no self-gravity. We run multiple simulations with different values of initial
mass ratio $q_0$ (the ratio of secondary over primary mass) and gas
temperature, and find a critical value of $q_{\rm c} = 0.25$ which
distinguishes the later evolution of mass ratio $q$ as a function of time. If
$q_0$ >~ $q_{\rm c}$, the secondary seed grows faster and $q$ increases
monotonically towards unity. If $q_0$ <~ $q_{\rm c}$, on the other hand, the
primary seed grows faster and $q$ is lower than $q_0$ at the end of the
simulation. Based on our numerical results, we analytically calculate the
long-term evolution of the seed binary including the growth of binary by gas
accretion. We find that the seed binary with $q_0$ >~ $q_{\rm c}$ evolves
towards an equal-mass binary star, and that with $q_0$ <~ $q_{\rm c}$ evolves
to a binary with an extreme value of $q$. Binary separation is a monotonically
increasing function of time for any $q_0$, suggesting that the binary growth by
accretion does not lead to the formation of close binaries.


title: Properties of isocalar-pair condensates

abstract:
  It is pointed out that the ground state of n neutrons and n protons in a
single-j shell, interacting through an isoscalar (T=0) pairing force, is not
paired, J=0, but rather spin-aligned, J=n. This observation is explained in the
context of a model of isoscalar P (J=1) pairs, which is mapped onto a system of
p bosons, leading to an approximate analytic solution of the isoscalar-pairing
limit in jj coupling.