title:
Star-Forming Galaxies Significantly Contribute to the Isotropic
  Gamma-Ray Background

abstract:
  The origin of the isotropic gamma-ray background (IGRB) --- the portion of
the extragalactic gamma-ray sky that is not resolvable into individual point
sources --- provides a powerful probe into the evolution of the high-energy
universe. Star-forming galaxies (SFGs) are among the most likely contributors
to the IGRB, though their contribution is difficult to constrain because their
flux distribution is dominated by numerous faint sources. We produce a novel
joint-likelihood analysis of the $\gamma$-ray emission from 584 SFGs, utilizing
advanced statistical techniques to compare the distribution of low-significance
excesses against the non-Poissonian $\gamma$-ray background fluctuations. We
first examine the theoretically well-motivated relationship between the far-IR
and $\gamma$-ray luminosities of SFGs, utilizing a model where the $\gamma$-ray
luminosity is given by log$_{10}$(L$_\gamma$/(erg s$^{-1}$)) = $\alpha$
log$_{10}$(L$_{IR}$/(10$^{10}$L$_\odot$)) + $\beta$. We calculate best-fit
parameters $\alpha$ = 1.18 $\pm$ 0.15, $\beta$ = 38.49 $\pm$ 0.24, with a
log-normal dispersion in this relationship given by $\sigma$ = 0.39 $\pm$ 0.12.
The best-fit values of $\alpha$ and $\beta$ are consistent with previous
studies. We find a larger dispersion in the far-IR to $\gamma$-ray correlation
than previous studies. This dispersion is significant at the level of
5.7$\sigma$. These results imply that SFGs significantly contribute to the
IGRB, producing between 61.0$^{+30.2}_{-18.3}\%$ of the total IGRB intensity
above an energy of 1 GeV. Along with recent works, this strongly indicates that
multiple source classes provide comparable contributions to the IGRB intensity.
We discuss the implication of these results for the interpretation of the
IceCube neutrinos.


title: Exotic Electroweak Signals in Twin Higgs

abstract:
  The Twin Higgs model is the preeminent example of a theory of neutral
naturalness, where the new particles that alleviate the little hierarchy
problem are Standard Model (SM) singlets. The most promising collider search
strategy, based on rare Higgs decays, is nevertheless not effective in
significant regions of the parameter space of the low energy theory. This
underlines the importance of phenomenological studies on ultraviolet
completions of the Twin Higgs model, which must lie at a scale lower than 5-10
TeV. We pursue this course in the context of non-supersymmetric completions,
focusing on exotic fermions that carry SM electroweak and twin color charges,
as well as on exotic vectors that transform as the bi-fundamental of the
electroweak or color groups. Both $Z_2$-preserving and $Z_2$-breaking mass
spectra are considered for the exotic fermions. In the former case they must be
heavier than $\sim 1$ TeV, but can still be sizably produced in the decays of
the color bi-fundamental vector. In the $Z_2$-breaking scenario, the exotic
fermions can have masses in the few hundred GeV range without significantly
increasing the fine-tuning. Once pair-produced through the electroweak
interactions, they naturally form bound states held together by the twin color
force, which subsequently annihilate back to SM particles. The associated
resonance signals are discussed in detail. We also outline the phenomenology of
the electroweak bi-fundamental vectors, some of which mix with the SM $W$ and
$Z$ and can therefore be singly produced in hadron collisions.


title:
Spin-switch Josephson junctions with magnetically tunable
  $\sin(\delta\varphi/n)$ shape

abstract:
  With a combination of simple analytical arguments and extensive numerical
simulations, we theoretically propose a Josephson junction with $n+1$
superconductors where the current-phase relation can be toggled in situ between
a $\sin(\delta\varphi)$ and $\sin(\delta\varphi/n)$ shape using an applied
magnetic field. Focusing in particular on the case $n=2$, we show that by using
realistic system parameters such as unequal interface transparencies, the
$\sin(\delta\varphi/2)$-shaped solution retains its $2\pi$-periodicity due to
discontinuities at $\delta\varphi = \pm \pi$. Moreover, we demonstrate that as
one toggles between the $\sin(\delta\varphi)$- and
$\sin(\delta\varphi/2)$-shaped solutions, the system acts as an on--off switch,
and can acheive more than two orders of magnitude difference between the
supercurrent in the on and off states. Finally, we argue that the same approach
can be generalized to switchable $\sin(\delta\varphi/n)$ junctions for
arbitrary integers~$n$, which we motivate by analytically solving the Josephson
equations for double- and triple-barrier junctions.


title:
Implications of an updated ultraviolet background for the ionization
  mechanisms of intervening Ne VIII absorbers

abstract:
  Ne VIII absorbers seen in QSO spectra are useful tracers of warm ionized gas,
when collisional ionization is the dominant ionization process. While
photoionization by the ultraviolet background (UVB) is a viable option, it
tends to predict large line-of-sight thickness for the absorbing gas. Here, we
study the implications of the recently updated UVB at low-z to understand the
ionization mechanisms of intervening Ne VIII absorbers. With the updated UVB,
one typically needs higher density and metallicity to reproduce the observed
ionic column densities under photoionization. Both reduce the inferred
line-of-sight thicknesses of the absorbers. We find a critical density of
$\geq5\times10^{-5}$ cm$^{-3}$ above which the observed N(Ne VIII)/N(O VI) can
be reproduced by pure collisional processes. If the gas is of near solar
metallicity (as measured for the low ions) then the cooling timescales will be
small (<$10^{8}$ yrs). Therefore, a continuous injection of heat is required in
order to enhance the detectability of the collisionally ionized gas. Using
photoionization models we find that in almost all Ne VIII systems the inferred
low ion metallicity is near solar or supersolar. If we assume the Ne VIII phase
to have similar metallicities then photoionization can reproduce the observed
N(Ne VIII)/N(O VI) without the line-of-sight thickness being unreasonably large
and avoids cooling issues related to the collisional ionization at these
metallicities. However the indication of broad Ly$\alpha$ absorption in a
couple of systems, if true, suggests that the Ne VIII phase is distinct from
the low ion phase having much lower metallicity.


title:
AGN-Host Connection at 0.5 < z < 2.5: A rapid evolution of AGN fraction
  in red galaxies during the last 10 Gyr

abstract:
  We explore the dependence of the incidence of moderate-luminosity ($L_{X} =
10^{41.9-43.7}$ erg s$^{-1}$) AGNs and the distribution of their accretion
rates on host color at 0.5 < z < 2.5, using deep X-ray data in GOODS fields. We
use extinction-corrected rest-frame U-V colors to divide both AGN hosts and
non-AGN galaxies into red sequence (quiescent), green valley (transition), and
blue cloud (star-forming) populations. We find that both the AGN fraction at
fixed stellar mass and its evolution with redshift are dependent on host
colors. Most notably, red galaxies have the lowest AGN fraction (~5\%) at z~1
yet with most rapid redshift evolution, increasing by a factor of 5 (~24\%) at
z~2. Green galaxies exhibit the highest AGN fraction across all redshifts,
which is most pronounced at z~2 with more than half of them hosting an AGN at
$M_{*} > 10^{10.6} M_{\odot}$. Together with the high AGN fraction in red
galaxies at z~2, this indicates that X-ray AGNs could be important in both
transforming blue galaxies into red ones and subsequently maintaining their
quiescence at high redshift. Furthermore, consistent with low-redshift studies,
we find that the probability of hosting an AGN in the total galaxy population
can be characterized by a universal Eddington ratio ($p(\lambda_{Edd}) \sim
\lambda_{Edd}^{-0.4}$) and a moderate redshift evolution. Yet consistent with
their different AGN fractions, different populations appear to also have
different $p(\lambda_{Edd})$ with red galaxies exhibiting more rapid redshift
evolution than green and blue ones. Evidence for a steeper power law of
$p(\lambda_{Edd})$ in red galaxies is also presented, though larger samples are
needed to confirm. These results suggest that the AGN accretion or the growth
of supermassive black holes is related to their host properties, and may also
influence their hosts in a different mode dependent on the host color.


title: Lognormal Distribution of Cosmic Voids in Simulations and Mocks

abstract:
  Following up on previous studies, we here complete a full analysis of the
void size distributions of the Cosmic Void Catalog (CVC) based on three
different simulation and mock catalogs; dark matter, haloes and galaxies. Based
on this analysis, we attempt to answer two questions: Is a 3-parameter
log-normal distribution a good candidate to satisfy the void size distributions
obtained from different types of environments? Is there a direct relation
between the shape parameters of the void size distribution and the
environmental effects? In an attempt to answer these questions, we here find
that all void size distributions of these data samples satisfy the 3-parameter
log-normal distribution whether the environment is dominated by dark matter,
haloes or galaxies. In addition, the shape parameters of the 3-parameter
log-normal void size distribution seem highly affected by environment,
particularly existing substructures. Therefore, we show two quantitative
relations given by linear equations between the skewness and the maximum tree
depth, and variance of the void size distribution and the maximum tree depth
directly from the simulated data. In addition to this, we find that the
percentage of the voids with nonzero central density in the data sets has a
critical importance. If the number of voids with nonzero central densities
reaches greater and or equal to 3.84 percentage in a simulation/mock sample,
then a second population is observed in the void size distributions. This
second population emerges as a second peak in the log-normal void size
distribution at larger radius.


title: Tails from the Orphanage

abstract:
  Examining a portion of the northern Sloan Digital Sky Survey (SDSS)
footprint, we detect at least three and possibly seven halo debris streams. One
of these (PS1-D) was recently detected in the Pan-STARRS1 $3\pi$ survey, and
the remaining two are also evident as extensions of the SDSS detections. All of
these streams are metal poor and are found at a distance of around $21 \pm 5$
kpc. The streams are between 65\arcdeg~ and 70\arcdeg~ in length, oriented
almost north-south, and are nearly parallel and somewhat convergent with the
neighboring Orphan stream. Surface densities ranging from 1.5 to 0.5 stars per
square degree down to $g = 21.7$ correspond to surface brightnesses between 35
and 37 mag per square arcsecond. The streams each appear to be more than 300 pc
across, suggesting either dwarf/ultrafaint galaxy progenitors or long-term
heating of very ancient globular cluster streams. The orbits of all but one of
these streams appear to be nearly radial, and the orbit normals suggest that
all of the streams are part of the Vast Polar Structure, a relatively narrow
plane that contains most of the known satellite galaxies, globular clusters,
and stellar streams.


title:
Arch2030: A Vision of Computer Architecture Research over the Next 15
  Years

abstract:
  Application trends, device technologies and the architecture of systems drive
progress in information technologies. However, the former engines of such
progress - Moore's Law and Dennard Scaling - are rapidly reaching the point of
diminishing returns. The time has come for the computing community to boldly
confront a new challenge: how to secure a foundational future for information
technology's continued progress. The computer architecture community engaged in
several visioning exercises over the years. Five years ago, we released a white
paper, 21st Century Computer Architecture, which influenced funding programs in
both academia and industry. More recently, the IEEE Rebooting Computing
Initiative explored the future of computing systems in the architecture,
device, and circuit domains. This report stems from an effort to continue this
dialogue, reach out to the applications and devices/circuits communities, and
understand their trends and vision. We aim to identify opportunities where
architecture research can bridge the gap between the application and device
domains.


title:
An upper bound on the Kolmogorov widths of a certain family of integral
  operators

abstract:
  We consider the family of integral operators $(K_{\alpha}f)(x)$ from
$L^p[0,1]$ to $L^q[0,1]$ given by $$(K_{\alpha}f)(x)=\int_0^1(1-xy)^{\alpha
-1}\,f(y)\,\operatorname{d}\!y, \qquad 0<\alpha<1.$$ The main objective is to
find upper bounds for the Kolmogorov widths, where the $n$th Kolmogorov width
is the infimum of the deviation of $(K_{\alpha}f)$ from an $n$-dimensional
subspaces of $L^p[0,1]$ (with the infimum taken over all $n$-dimensional
subspaces), and is therefore a measure of how well $K_{\alpha}$ can be
approximated. We find upper bounds for the Kolmogorov widths in question that
decrease faster than $\exp(-\kappa \sqrt{n})$ for some positive constant
$\kappa$.


title:
Collaborative Mobile Edge Computing in 5G Networks: New Paradigms,
  Scenarios, and Challenges

abstract:
  Mobile Edge Computing (MEC) is an emerging paradigm that provides computing,
storage, and networking resources within the edge of the mobile Radio Access
Network (RAN). MEC servers are deployed on generic computing platform within
the RAN and allow for delay-sensitive and context-aware applications to be
executed in close proximity to the end users. This approach alleviates the
backhaul and core network and is crucial for enabling low-latency,
high-bandwidth, and agile mobile services. This article envisages a real-time,
context-aware collaboration framework that lies at the edge of the RAN,
constituted of MEC servers and mobile devices, and that amalgamates the
heterogeneous resources at the edge. Specifically, we introduce and study three
strong use cases ranging from mobile-edge orchestration, collaborative caching
and processing and multi-layer interference cancellation. We demonstrate the
promising benefits of these approaches in facilitating the evolution to 5G
networks. Finally, we discuss the key technical challenges and open-research
issues that need to be addressed in order to make an efficient integration of
MEC into 5G ecosystem.


title:
Polarimetric evidence of a white dwarf pulsar in the binary system AR
  Scorpii

abstract:
  The variable star AR Sco was recently discovered to pulse in brightness every
1.97 min from ultraviolet wavelengths into the radio regime. The system is
composed of a cool, low-mass star in a tight, 3.55 hr orbit with a more massive
white dwarf. Here we report new optical observations of AR Sco that show strong
linear polarization (up to 40%) which varies strongly and periodically on both
the spin period of the white dwarf and the beat period between the spin and
orbital period, as well as low level (< a few %) circular polarization. These
observations support the notion that, similar to neutron star pulsars, the
pulsed luminosity of AR Sco is powered by the spin-down of the rapidly-rotating
white dwarf which is highly magnetised (up to 500 MG). The morphology of the
modulated linear polarization is similar to that seen in the Crab pulsar,
albeit with a more complex waveform owing to the presence of two periodic
signals of similar frequency. Magnetic interactions between the two component
stars, coupled with synchrotron radiation from the white dwarf, power the
observed polarized and non-polarized emission. AR Scorpii is therefore the
first example of a white dwarf pulsar.


title: Low-Rank Inducing Norms with Optimality Interpretations

abstract:
  Optimization problems with rank constraints appear in many diverse fields
such as control, machine learning and image analysis. Since the rank constraint
is non-convex, these problems are often approximately solved via convex
relaxations. Nuclear norm regularization is the prevailing convexifying
technique for dealing with these types of problem. This paper introduces a
family of low-rank inducing norms and regularizers which includes the nuclear
norm as a special case. A posteriori guarantees on solving an underlying rank
constrained optimization problem with these convex relaxations are provided. We
evaluate the performance of the low-rank inducing norms on three matrix
completion problems. In all examples, the nuclear norm heuristic is
outperformed by convex relaxations based on other low-rank inducing norms. For
two of the problems there exist low-rank inducing norms that succeed in
recovering the partially unknown matrix, while the nuclear norm fails. These
low-rank inducing norms are shown to be representable as semi-definite
programs. Moreover, these norms have cheaply computable proximal mappings,
which makes it possible to also solve problems of large size using first-order
methods.


title:
The NANOGrav Nine-Year Data Set: Measurement and Interpretation of
  Variations in Dispersion Measures

abstract:
  We analyze dispersion measure (DM) variations of 37 millisecond pulsars in
the 9-year NANOGrav data release and constrain the sources of these variations.
Variations are significant for nearly all pulsars, with characteristic
timescales comparable to or even shorter than the average spacing between
observations. Five pulsars have periodic annual variations, 14 pulsars have
monotonically increasing or decreasing trends, and 13 pulsars show both
effects. Several pulsars show correlations between DM excesses and lines of
sight that pass close to the Sun. Mapping of the DM variations as a function of
the pulsar trajectory can identify localized ISM features and, in one case, an
upper limit to the size of the dispersing region of 13.2 AU. Finally, five
pulsars show very nearly quadratic structure functions, which could be
indicative of an underlying Kolmogorov medium. Four pulsars show roughly
Kolmogorov structure functions and another four show structure functions less
steep than Kolmogorov. One pulsar has too large an uncertainty to allow
comparisons. We discuss explanations for apparent departures from a
Kolmogorov-like spectrum, and show that the presence of other trends in the
data is the most likely cause.


title:
Symplectic Asphericity, Category Weight, and Closed Characteristics of
  K-Contact Manifolds

abstract:
  Let $M$ be a closed K-contact $(2n+1)$-manifold equipped with a quasi-regular
K-contact structure. Rukimbira proved that the Reeb vector field $\xi$ of this
structure has at least $n+1$ closed characteristics. We note that $\xi$ has at
least $2n+1$ closed characteristics provided that the space of leaves of the
foliation determined by $\xi$ is symplectically aspherical.


title: Quantum caustics in resonance fluorescence trajectories

abstract:
  We employ phase-sensitive amplification to perform homodyne detection of the
resonance fluorescence from a driven superconducting artificial atom.
Entanglement between the emitter and its fluorescence allows us to track the
individual quantum state trajectories of the emitter conditioned on the
outcomes of the field measurements. We analyze the ensemble properties of these
trajectories by considering trajectories that connect specific initial and
final states. By applying the stochastic path integral formalism, we calculate
equations-of-motion for the most likely path between two quantum states and
compare these predicted paths to experimental data. Drawing on the mathematical
similarity between the action formalism of the most likely quantum paths and
ray optics we study the emergence of caustics in quantum trajectories---places
where multiple extrema in the stochastic action occur. We observe such multiple
most likely paths in experimental data and find these paths to be in reasonable
quantitative agreement with theoretical calculations.

categories: quant-ph cond-mat.mes-hall physics.atom-ph physics.optics


title: One-loop divergences in 6D, N=(1,0) SYM theory

abstract:
  We consider, in the harmonic superspace approach, the six-dimensional N=(1,0)
supersymmetric Yang-Mills gauge multiplet minimally coupled to a hypermultiplet
in an arbitrary representation of the gauge group. Using the superfield
proper-time and background-field techniques, we compute the divergent part of
the one-loop effective action depending on both the gauge multiplet and the
hypermultiplet. We demonstrate that in the particular case of N=(1,1) SYM
theory, which corresponds to the hypermultiplet in the adjoint representation,
all one-loop divergencies vanish, so that N=(1,1) SYM theory is one-loop finite
{\it off shell}.


title: Multiparty testing preorders

abstract:
  Variants of the must testing approach have been successfully applied in
Service Oriented Computing for analysing the compliance between (contracts
exposed by) clients and servers or, more generally, between two peers. It has
however been argued that multiparty scenarios call for more permissive notions
of compliance because partners usually do not have full coordination
capabilities. We propose two new testing preorders, which are obtained by
restricting the set of potential observers. For the first preorder, called
uncoordinated, we allow only sets of parallel observers that use different
parts of the interface of a given service and have no possibility of
intercommunication. For the second preorder, that we call individualistic, we
instead rely on parallel observers that perceive as silent all the actions that
are not in the interface of interest. We have that the uncoordinated preorder
is coarser than the classical must testing preorder and finer than the
individualistic one. We also provide a characterisation in terms of decorated
traces for both preorders: the uncoordinated preorder is defined in terms of
must-sets and Mazurkiewicz traces while the individualistic one is described in
terms of classes of filtered traces that only contain designated visible
actions and must-sets.


title: Breaking symmetry, breaking ground

abstract:
  I give a short commentary on a seminal article by T W B Kibble in 1976,
"Topology of cosmic domains and strings".


title: Uncovering hidden flows in physical networks

abstract:
  Understanding the interactions among nodes in a complex network is of great
importance, since they disclose how these nodes are cooperatively supporting
the functioning of the network. Scientists have developed numerous methods to
uncover the underlying adjacent physical connectivity based on measurements of
functional quantities of the nodes states. Often, the physical connectivity,
the adjacency matrix, is available. Yet, little is known about how this
adjacent connectivity impacts on the "hidden" flows being exchanged between any
two arbitrary nodes, after travelling longer non-adjacent paths. In this
Letter, we show that hidden physical flows in conservative flow networks, a
quantity that is usually inaccessible to measurements, can be determined by the
interchange of physical flows between any pair of adjacent nodes. Our approach
applies to steady or dynamic state of either linear or non-linear complex
networks that can be modelled by conservative flow networks, such as gas supply
networks, water supply networks and power grids.


title: Holography of Wi-Fi radiation

abstract:
  Wireless data transmission systems such as WiFi or Bluetooth emit coherent
light - electromagnetic waves with precisely known amplitude and phase.
Propagating in space, this radiation forms a hologram - a two-dimensional
wavefront encoding a three-dimensional view of all objects traversed by the
light beam. Here we demonstrate a scheme to record this hologram in a
phase-coherent fashion across a meter-sized imaging region. We recover
three-dimensional views of objects and emitters by feeding the resulting data
into digital reconstruction algorithms. Employing a digital implementation of
dark field propagation to suppress multipath reflection we significantly
enhance the quality of the resulting images.


title:
No equations, no parameters, no variables: data, and the reconstruction
  of normal forms by learning informed observation geometries

abstract:
  The discovery of physical laws consistent with empirical observations lies at
the heart of (applied) science and engineering. These laws typically take the
form of nonlinear differential equations depending on parameters, dynamical
systems theory provides, through the appropriate normal forms, an "intrinsic",
prototypical characterization of the types of dynamical regimes accessible to a
given model. Using an implementation of data-informed geometry learning we
directly reconstruct the relevant "normal forms": a quantitative mapping from
empirical observations to prototypical realizations of the underlying dynamics.
Interestingly, the state variables and the parameters of these realizations are
inferred from the empirical observations, without prior knowledge or
understanding, they parametrize the dynamics {\em intrinsically}, without
explicit reference to fundamental physical quantities.


title: A generalized priority-based model for smartphone screen touches

abstract:
  The distribution of intervals between human actions such as email posts or
keyboard strokes demonstrates distinct properties at short vs long time scales.
For instance, at long time scales, which are presumably controlled by complex
process such as planning and decision making, it has been shown that those
inter-event intervals follow a scale-invariant (or power-law) distribution. In
contrast, at shorter time-scales - which are governed by different process such
as sensorimotor skill - they do not follow the same distribution and little do
we know how they relate to the scale-invariant pattern. Here, we analyzed 9
millions intervals between smartphone screen touches of 84 individuals which
span several orders of magnitudes (from milliseconds to hours). To capture
these intervals, we extend a priority-based generative model to smartphone
touching events. At short-time scale, the model is governed by refractory
effects, while at longer time scales, the inter-touch intervals are governed by
the priority difference between smartphone tasks and other tasks. The
flexibility of the model allows to capture inter-individual variations at short
and long time scales while its tractability enables efficient model fitting.
According to our model, each individual has a specific power-low exponent which
is tightly related to the effective refractory time constant suggesting that
motor processes which influence the fast actions are related to the higher
cognitive processes governing the longer inter-event intervals.


title:
Bistable Circuit Behaviour as a 2 level (stable/metastable) potential
  energy system

abstract:
  A novel model of analyzing Schmitt trigger as 2 level (metastable/stable)
energy system is presented. The energy of the 2 level system is identified. In
an MOS implementation, this arises from the electrostatic potential energy of
the electrons on the gate to source capacitance of the cross coupled MOS
transistors. The electrostatic energy, upon co-ordinate transformation,
(incorporating the nonlinear MOS device behaviour and cross coupling), yields
an expression for the 2 level system energy. The 2 level system, described
under the transformed co-ordinate, is simulated. Simulation on the dynamics of
the system shows a metastsable state and two stable states, corresponding to
the a maximum(metastable) energy and a minimum(stable) energy, as predicted by
the energy expression in the model. This result agrees with earlier attempt
based on nonlinear dynamic system approach, whereby the potential is
interpreted from the point of view of the gradient of vector field. In
addition, the model gives physical design insight on how the change in circuit
parameters (such as gm, R), affects the energy characteristics, hence leads to
effective design of such 2 level system.


title: Macroscopic non-classical state preparation via post-selection

abstract:
  Macroscopic mechanical qubits are fundamental both to test the
classical-quantum boundary and present suitable candidates for quantum
information processing. Motivated by these, we propose a feasible probabilistic
scheme to generate an on-demand mechanical qubit, as well as Schr\"{o}dinger's
cat and Fock number states. In order to accomplish this proposal, we study an
open dispersive spin-mechanical system in the absence of any external driving.
The procedure is solely based on spin post-selection in the weak coupling
regime. Through this scheme we demonstrate that the achieved superposition is
closely related to the amplification of the mean values of the mechanical
quadratures as they are associated to the maximum quantum coherence.


title: On the integral law of thermal radiation

abstract:
  The integral law of thermal radiation by finite size emitters is studied. Two
geometrical characteristics of a radiating body or a cavity, its volume and its
boundary area, define two terms in its radiance. The term defined by the volume
corresponds to the Stefan-Boltzmann law. The term defined by the boundary area
is proportional to the third power of temperature and inversely proportional to
the emitter's effective size, which is defined as the ratio of its volume to
its boundary area. It is shown that the cubic temperature contribution is
observed in experiments. This term explains the intrinsic uncertainty of the
NPL experiment on radiometric determination of the Stefan-Boltzmann constant.
It is also quantitatively confirmed by data from the NIST calibration of
cryogenic blackbodies. Its relevance to the size of source effect in optical
radiometry is proposed. The conjecture that this generalized law is valid for
arbitrary temperature and effective size is supported by the experiments on
thermal emission from nano-heaters.


title:
Modulation of mechanical resonance by chemical potential oscillation in
  graphene

abstract:
  The classical picture of the force on a capacitor assumes a large density of
electronic states, such that the electrochemical potential of charges added to
the capacitor is given by the external electrostatic potential and the
capacitance is determined purely by geometry. Here we consider capacitively
driven motion of a nano-mechanical resonator with a low density of states, in
which these assumptions can break down. We find three leading-order corrections
to the classical picture: the first of is a modulation in the static force due
to variation in the internal chemical potential, the second and third are
change in static force and dynamic spring constant due to the rate of change of
chemical potential, expressed as the quantum (density of states) capacitance.
As a demonstration, we study a capacitively driven graphene mechanical
resonators, where the chemical potential is modulated independently of the gate
voltage using an applied magnetic field to manipulate the energy of electrons
residing in discrete Landau levels. In these devices, we observe large periodic
frequency shifts consistent with the three corrections to the classical
picture. In devices with extremely low strain and disorder, the first
correction term dominates and the resonant frequency closely follows the
chemical potential. The theoretical model fits the data with only one
adjustable parameter representing disorder-broadening of the Landau levels. The
underlying electromechanical coupling mechanism is not limited the particular
choice of material, geometry, or mechanism for variation in chemical potential,
and can thus be extended to other low-dimensional systems.


title: Disproof of a widely-accepted mathematical conjecture

abstract:
  A mathematical conjecture is successfully identified, which is used for
relativistic analysis of dielectric Einstein-box thought experiment in a Letter
(Ramos, Rubilar, and Obukhov, Phys. Lett. A 375, 1703 (2011)), where the
authors conjecture (without any citations) that, the symmetry and
divergence-less property of a Lorentz 4-tensor is a sufficient condition for
the time-column space integrals to constitute a Lorentz 4-vector. This
mathematical conjecture has been thought to be "a mathematical fact the
validity of which was shown well" in textbooks. However in this paper, we
indicate that this conjecture has never been proved mathematically. By
enumerating a counterexample, we find that this mathematical conjecture is
flawed, and it is not persuasive to use a flawed mathematical conjecture as a
starting point to resolve Abraham-Minkowski controversy over light momentum in
a dielectric medium. We also indicate that this flawed mathematical conjecture
is actually a widely-accepted conjecture in the dynamics of relativity in
textbooks for many decades. To eliminate a misunderstanding of this flawed
conjecture in the community, we provide a detailed elucidation of why
M{\o}ller's mathematical statement, also called "M{\o}ller's version of von
Laue's theorem", only defines a trivial zero 4-vector for an electromagnetic
stress-energy Lorentz 4-tensor.


title:
Fractional derivatives of constant and variable orders applied to
  anomalous relaxation models in heat-transfer problems

abstract:
  In the present paper, we address a class of the fractional derivatives of
constant and variable orders for the first time. Fractional-order relaxation
equations of constants and variable orders in the sense of Caputo type are
modeled from mathematical view of point. The comparative results of the
anomalous relaxation among the various fractional derivatives are also given.
They are very efficient in description of the complex phenomenon arising in
heat transfer.


title:
Slow motion for one-dimensional nonlinear damped hyperbolic Allen-Cahn
  systems

abstract:
  We consider a nonlinear damped hyperbolic reaction-diffusion system in a
bounded interval of the real line with homogeneous Neumann boundary conditions
and we study the metastable dynamics of the solutions. Using an "energy
approach" introduced by Bronsard and Kohn [CPAM 1990] to study slow motion for
Allen-Cahn equation and improved by Grant [SIAM J. Math. Anal. 1995] in the
study of Cahn-Morral systems, we improve and extend to the case of systems the
results valid for the hyperbolic Allen-Cahn equation. In particular, we study
the limiting behavior of the solutions as $\varepsilon\to0^+$, where
$\varepsilon^2$ is the diffusion coefficient, and we prove existence and
persistence of metastable states for a time
$T_\varepsilon>\exp(A/\varepsilon)$. Such metastable states have a transition
layer structure and the transition layers move with exponentially small
velocity.


title:
The Dynamic Spectrum Aggregation Strategy for Cognitive Networks Based
  on Markov Model

abstract:
  In order to meet the constantly increasing demand by mobile terminals for
higher data rates with limited wireless spectrum resource, cognitive radio and
spectrum aggregation technologies have attracted much attention due to its
capacity in improving spectrum efficiency. Combing cognitive relay and spectrum
aggregation technologies, in this paper, we propose a dynamic spectrum
aggregation strategy based on the Markov Prediction of the state of spectrum
for the cooperatively relay networks on a multi-user and multi-relay scenario
aiming at ensuring the user channel capacity and maximizing the network
throughput. The spectrum aggregation strategy is executed through two steps.
First, predict the state of spectrum through Markov prediction. Based on the
prediction results of state of spectrum, a spectrum aggregation strategy is
proposed. Simulation results show that the spectrum prediction process can
observably lower the outage rate, and the spectrum aggregation strategy can
greatly improve the network throughput.


title:
Evaluating Creative Language Generation: The Case of Rap Lyric
  Ghostwriting

abstract:
  Language generation tasks that seek to mimic human ability to use language
creatively are difficult to evaluate, since one must consider creativity,
style, and other non-trivial aspects of the generated text. The goal of this
paper is to develop evaluation methods for one such task, ghostwriting of rap
lyrics, and to provide an explicit, quantifiable foundation for the goals and
future directions of this task. Ghostwriting must produce text that is similar
in style to the emulated artist, yet distinct in content. We develop a novel
evaluation methodology that addresses several complementary aspects of this
task, and illustrate how such evaluation can be used to meaningfully analyze
system performance. We provide a corpus of lyrics for 13 rap artists, annotated
for stylistic similarity, which allows us to assess the feasibility of manual
evaluation for generated verse.


title: Almost-sure quasiperiodicity in countably many co-existing circles

abstract:
  In many dynamical systems, countably infinitely many invariant tori co-exist.
The occurrence of quasiperiodicity on any one of these tori is sometimes
sufficient to establish strong global properties, like dense trajectories and
periodic points. In this paper, we establish sufficient conditions for a
countably infinite collection of parameterized circle diffeomorphisms to have
quasiperiodic behavior on at least one of the circles, for a full Lebesgue
measure set of the parameter values. As an application, we study parameterized
families of skew-product maps on the torus and prove sufficient conditions for
the existence of at least on quasiperiodic circle for Lebesgue-almost every
parameter value.


title:
Search for $CP$ violation in the phase space of
  $D^0\rightarrow\pi^+\pi^-\pi^+\pi^-$ decays

abstract:
  A search for time-integrated $CP$ violation in the Cabibbo-suppressed decay
$\mbox{$D^0\rightarrow\pi^+\pi^-\pi^+\pi^-$}$ is performed using an unbinned,
model-independent technique known as the energy test. This is the first
application of the energy test in four-body decays. The search is performed for
$P$-even $CP$ asymmetries and, for the first time, is extended to probe the
$P$-odd case. Using proton-proton collision data corresponding to an integrated
luminosity of 3.0 fb$^{-1}$ collected by the LHCb detector at centre-of-mass
energies of $\sqrt{s}=$7 TeV and 8 TeV, the world's best sensitivity to $CP$
violation in this decay is obtained. The data are found to be consistent with
the hypothesis of $CP$ symmetry with a $p$-value of $(4.6\pm0.5)\%$ in the
$P$-even case, and marginally consistent with a $p$-value of $(0.6\pm0.2)\%$ in
the $P$-odd case, corresponding to a significance for $CP$ non-conservation of
2.7 standard deviations.


title:
A condition for purely absolutely continuous spectrum for CMV operators
  using the density of states

abstract:
  We prove an averaging formula for the derivative of the absolutely continuous
part of the density of states measure for an ergodic family of CMV matrices. As
a consequence, we show that the spectral type of such a family is almost surely
purely absolutely continuous if and only if the density of states is absolutely
continuous and the Lyapunov exponent vanishes almost everywhere with respect to
the same. Both of these results are CMV operator analogues of theorems obtained
by Kotani for Schr\"odinger operators.


title:
Weak convergence rates for numerical approximations of stochastic
  partial differential equations with nonlinear diffusion coefficients in UMD
  Banach spaces

abstract:
  Strong convergence rates for numerical approximations of semilinear
stochastic partial differential equations (SPDEs) with smooth and regular
nonlinearities are well understood in the literature. Weak convergence rates
for numerical approximations of such SPDEs have been investigated for about two
decades and are still not yet fully understood. In particular, no essentially
sharp weak convergence rates are known for temporal or spatial numerical
approximations of space-time white noise driven SPDEs with nonlinear
multiplication operators in the diffusion coefficients. In this article we
overcome this problem by establishing essentially sharp weak convergence rates
for exponential Euler approximations of semilinear SPDEs with nonlinear
multiplication operators in the diffusion coefficients. Key ingredients of our
approach are applications of the mild It\^{o} type formula in UMD Banach spaces
with type 2.


title: On the mild It\^o formula in Banach spaces

abstract:
  The mild Ito formula proposed in Theorem 1 in [Da Prato, G., Jentzen, A., \&
R\"ockner, M., A mild Ito formula for SPDEs, arXiv:1009.3526 (2012), To appear
in the Trans.\ Amer.\ Math.\ Soc.] has turned out to be a useful instrument to
study solutions and numerical approximations of stochastic partial differential
equations (SPDEs) which are formulated as stochastic evolution equations (SEEs)
on Hilbert spaces. In this article we generalize this mild It\^o formula so
that it is applicable to solutions and numerical approximations of SPDEs which
are formulated as SEEs on UMD (unconditional martingale differences) Banach
spaces. This generalization is especially useful for proving essentially sharp
weak convergence rates for numerical approximations of SPDEs.


title:
DeepCancer: Detecting Cancer through Gene Expressions via Deep
  Generative Learning

abstract:
  Transcriptional profiling on microarrays to obtain gene expressions has been
used to facilitate cancer diagnosis. We propose a deep generative machine
learning architecture (called DeepCancer) that learn features from unlabeled
microarray data. These models have been used in conjunction with conventional
classifiers that perform classification of the tissue samples as either being
cancerous or non-cancerous. The proposed model has been tested on two different
clinical datasets. The evaluation demonstrates that DeepCancer model achieves a
very high precision score, while significantly controlling the false positive
and false negative scores.


title:
Complex Quasi-Two-Dimensional Crystalline Order Embedded in VO$_2$ and
  Other Crystals

abstract:
  Metal oxides such as VO$_2$ undergo structural transitions to low-symmetry
phases characterized by intricate crystalline order, accompanied by rich
electronic behavior. We derive a minimal ionic Hamiltonian based on symmetry
and local energetics which describes structural transitions involving all four
observed phases, in the correct order. An exact analysis shows that complexity
results from the symmetry-induced constraints of the parent phase which forces
ionic displacements to form multiple interpenetrating groups using
low-dimensional pathways and distant neighbors. Displacements within each group
exhibit independent, quasi two-dimensional order, which is frustrated and
fragile. This selective ordering mechanism is not restricted to VO$_2$: it
applies to other oxides which show similar complex order.


title: Ordered Probability Spaces

abstract:
  Let $C$ be an open cone in a Banach space equipped with the Thompson metric
with closure a normal cone. The main result gives sufficient conditions for
Borel probability measures $\mu,\nu$ on $C$ with finite first moment for which
$\mu\leq \nu$ in the stochastic order induced by the cone to be order
approximated by sequences $\{\mu_n\},\{\nu_n\}$ of uniform finitely supported
measures in the sense that $\mu_n\leq \nu_n$ for each $n$ and $\mu_n\to \mu$,
$\nu_n\to \nu$ in the Wasserstein metric. This result is the crucial tool in
developing a pathway for extending various inequalities on operator and matrix
means, which include the harmonic, geometric, and arithmetic operator means on
the cone of positive elements of a $C^*$-algebra, to the space
$\mathcal{P}^1(C)$ of Borel measures of finite first moment on $C$. As an
illustrative particular application, we obtain the monotonicity of the Karcher
geometric mean on $\mathcal{P}^1(\mathbb{A}^+)$ for the positive cone
$\mathbb{A}^+$ of a $C^*$-algebra $\mathbb{A}$.


title:
Towards deep learning with spiking neurons in energy based models with
  contrastive Hebbian plasticity

abstract:
  In machine learning, error back-propagation in multi-layer neural networks
(deep learning) has been impressively successful in supervised and
reinforcement learning tasks. As a model for learning in the brain, however,
deep learning has long been regarded as implausible, since it relies in its
basic form on a non-local plasticity rule. To overcome this problem,
energy-based models with local contrastive Hebbian learning were proposed and
tested on a classification task with networks of rate neurons. We extended this
work by implementing and testing such a model with networks of leaky
integrate-and-fire neurons. Preliminary results indicate that it is possible to
learn a non-linear regression task with hidden layers, spiking neurons and a
local synaptic plasticity rule.


title: Orlicz--Lorentz centroid bodies

abstract:
  We extend the definition of the centroid body operator to an Orlicz--Lorentz
centroid body operator on the star bodies in $\mathbb R^n$, and establish the
sharp affine isoperimetric inequality that bounds (from below) the volume of
the Orlicz--Lorentz centroid body of any convex body containing the origin in
its interior by the volume of this convex body.


title: #HashtagWars: Learning a Sense of Humor

abstract:
  In this work, we present a new dataset for computational humor, specifically
comparative humor ranking, which attempts to eschew the ubiquitous binary
approach to humor detection. The dataset consists of tweets that are humorous
responses to a given hashtag. We describe the motivation for this new dataset,
as well as the collection process, which includes a description of our
semi-automated system for data collection. We also present initial experiments
for this dataset using both unsupervised and supervised approaches. Our best
supervised system achieved 63.7% accuracy, suggesting that this task is much
more difficult than comparable humor detection tasks. Initial experiments
indicate that a character-level model is more suitable for this task than a
token-level model, likely due to a large amount of puns that can be captured by
a character-level model.


title: Automatic Lymphocyte Detection in H&E Images with Deep Neural Networks

abstract:
  Automatic detection of lymphocyte in H&E images is a necessary first step in
lots of tissue image analysis algorithms. An accurate and robust automated
lymphocyte detection approach is of great importance in both computer science
and clinical studies. Most of the existing approaches for lymphocyte detection
are based on traditional image processing algorithms and/or classic machine
learning methods. In the recent years, deep learning techniques have
fundamentally transformed the way that a computer interprets images and have
become a matchless solution in various pattern recognition problems. In this
work, we design a new deep neural network model which extends the fully
convolutional network by combining the ideas in several recent techniques, such
as shortcut links. Also, we design a new training scheme taking the prior
knowledge about lymphocytes into consideration. The training scheme not only
efficiently exploits the limited amount of free-form annotations from
pathologists, but also naturally supports efficient fine-tuning. As a
consequence, our model has the potential of self-improvement by leveraging the
errors collected during real applications. Our experiments show that our deep
neural network model achieves good performance in the images of different
staining conditions or different types of tissues.


title: Essential norms of Volterra and Ces\`aro operators on M\"untz spaces

abstract:
  We study the properties of the Volterra and Ces\`aro operators viewed on the
$L^1$-M\"untz space $M_\Lambda^1$ with range in the space of continuous
functions. These operators are neither compact nor weakly compact. We estimate
how far from being (weakly) compact they are by computing their (generalized)
essential norm. It turns out that this latter does not depend on $\Lambda$ and
is equal to $1/2$.


title:
Uncertainties in Atmospheric Muon-Neutrino Fluxes Arising from
  Cosmic-Ray Primaries

abstract:
  We present an updated calculation of the uncertainties on the atmospheric
muon-neutrino flux arising from cosmic-ray primaries. For the first time, we
include recent measurements of the cosmic-ray primaries collected since 2005.
We apply a statistical technique that allows the determination of correlations
between the parameters of the GSHL primary-flux parametrisation and the
incorporation of these correlations into the uncertainty on the muon-neutrino
flux. We obtain an uncertainty related to the primary cosmic rays of around
$(5\text{--}15)\%$, depending on energy, which is about a factor of two smaller
than the previously determined uncertainty. The hadron production uncertainty
is added in quadrature to obtain the total uncertainty on the neutrino flux,
which is reduced by $\approx 5\%$. To take into account an unexpected hardening
of the spectrum of primaries above energies of $100$ $\text{GeV}$ observed in
recent measurements, we propose an alternative parametrisation and discuss its
impact on the neutrino flux uncertainties.


title:
Dynamic Scheduling for Delay Guarantees for Heterogeneous Cognitive
  Radio Users

abstract:
  We study an uplink multi secondary user (SU) system having statistical delay
constraints, and an average interference constraint to the primary user (PU).
SUs with heterogeneous interference channel statistics, to the PU, experience
heterogeneous delay performances since SUs causing low interference are
scheduled more frequently than those causing high interference. We propose a
scheduling algorithm that can provide arbitrary average delay guarantees to SUs
irrespective of their statistical channel qualities. We derive the algorithm
using the Lyapunov technique and show that it yields bounded queues and satisfy
the interference constraints. Using simulations, we show its superiority over
the Max-Weight algorithm.


title:
Continuum modeling of the effect of surface area growth due to crushing
  and damage on the permeability of granular rocks

abstract:
  This paper discusses a continuum approach to track the evolution of
permeability in granular rocks by accounting for the combined effect of
porosity changes, grain breakage and cement bond damage. To account for such a
broad range of microscopic processes under general loading paths, the Breakage
Mechanics theory is used and the computed mechanical response is linked with
the Kozeny equation, i.e. a permeability model able to evaluate the reduction
of the hydraulic conductivity resulting from the simultaneous loss of porosity
and growth of surface area. In particular, the evolution of the internal
variables of the model has been linked to idealized geometric schemes at
particle scale, with the goal to distinguish the contribution of the fines
generated by the disaggregation of the cement matrix from that of the broken
fragments resulting from the crushing of the skeleton. Compression/flow
experiments available in the literature for different granular rocks are used
to validate the proposed methodology. The analyses illustrate that the drop of
the permeability of damaged rocks would be severely underestimated without an
accurate computation of the growth of surface area, as well as that the
distributed fragmentation of skeleton particles tends to have stronger
implications than the generation of cement fines. These findings, along with
the satisfactory agreement between model predictions and experiments, stress
the benefits of adopting microstructure-based constitutive laws for the
analysis of coupled hydro-mechanical problems.


title: Fabrication-constrained nanophotonic inverse design

abstract:
  A major difficulty in applying computational design methods to nanophotonic
devices is ensuring that the resulting designs are fabricable. Here, we
describe a general inverse design algorithm for nanophotonic devices that
directly incorporates fabrication constraints. To demonstrate the capabilities
of our method, we designed a spatial-mode demultiplexer, wavelength
demultiplexer, and directional coupler. We also designed and experimentally
demonstrated a compact, broadband $1 \times 3$ power splitter on a silicon
photonics platform. The splitter has a footprint of only $3.8 \times
2.5~\mathrm{\mu m}$, and is well within the design rules of a typical silicon
photonics process, with a minimum radius of curvature of $100~\mathrm{nm}$.
Averaged over the designed wavelength range of $1400 - 1700~\mathrm{nm}$, our
splitter has a measured insertion loss of $0.642 \pm 0.057 ~\mathrm{dB}$ and
power uniformity of $0.641 \pm 0.054~\mathrm{dB}$.


title:
Modeling Single Molecule Junction Mechanics as a Probe of Interface
  Bonding

abstract:
  Using the atomic force microscope based break junction approach, applicable
to metal point contacts and single molecule junctions, measurements can be
repeated thousands of times resulting in rich data sets characterizing the
properties of an ensemble of nanoscale junction structures. This paper focuses
on the relationship between the measured force extension characteristics
including bond rupture and the properties of the interface bonds in the
junction. A set of exemplary model junction structures have been analyzed using
density functional theory based calculations to simulate the adiabatic
potential surface that governs the junction elongation. The junction structures
include representative molecules that bond to the electrodes through amine,
methylsulfide and pyridine links. The force extension characteristics are shown
to be most effectively analyzed in a scaled form with maximum sustainable force
and the distance between the force zero and force maximum as scale factors.
Widely used, two parameter models for chemical bond potential energy versus
bond length are found to be nearly identical in scaled form. Furthermore, they
fit well to the present calculations of N-Au and S-Au donor-acceptor bonds,
provided no other degrees of freedom are allowed to relax. Examination of the
reduced problem of a single interface, but including relaxation of atoms
proximal to the interface bond, shows that a single-bond potential form
renormalized by an effective harmonic potential in series fits well to the
calculated results. This allows relatively accurate extraction of the interface
bond energy. Analysis of full junction models show cooperative effects that go
beyond the series inclusion of the second bond in the junction, the spectator
bond that does not rupture.


title: Finding Better Active Learners for Faster Literature Reviews

abstract:
  Literature reviews can be time-consuming and tedious to complete. By
cataloging and refactoring three state-of-the-art active learning techniques
from evidence-based medicine and legal electronic discovery, this paper finds
and implements FASTREAD, a faster technique for studying a large corpus of
documents. This paper assesses FASTREAD using datasets generated from existing
SE literature reviews (Hall, Wahono, Radjenovi\'c, Kitchenham et al.). Compared
to manual methods, FASTREAD lets researchers find 95% relevant studies after
reviewing an order of magnitude fewer papers. Compared to other
state-of-the-art automatic methods, FASTREAD reviews 20-50% fewer studies while
finding same number of relevant primary studies in a systematic literature
review.


title: Optimal Generalized Decision Trees via Integer Programming

abstract:
  Decision trees have been a very popular class of predictive models for
decades due to their interpretability and good performance on categorical
features. However, they are not always robust and tend to overfit the data.
Additionally, if allowed to grow large, they lose interpretability. In this
paper, we present a mixed integer programming formulation to construct optimal
decision trees of a prespecified size. We take the special structure of
categorical features into account and allow combinatorial decisions (based on
subsets of values of features) at each node. Our approach can also handle
numerical features via thresholding. We show that very good accuracy can be
achieved with small trees using moderately-sized training sets. The
optimization problems we solve are tractable with modern solvers.


title: Active Learning for Speech Recognition: the Power of Gradients

abstract:
  In training speech recognition systems, labeling audio clips can be
expensive, and not all data is equally valuable. Active learning aims to label
only the most informative samples to reduce cost. For speech recognition,
confidence scores and other likelihood-based active learning methods have been
shown to be effective. Gradient-based active learning methods, however, are
still not well-understood. This work investigates the Expected Gradient Length
(EGL) approach in active learning for end-to-end speech recognition. We justify
EGL from a variance reduction perspective, and observe that EGL's measure of
informativeness picks novel samples uncorrelated with confidence scores.
Experimentally, we show that EGL can reduce word errors by 11\%, or
alternatively, reduce the number of samples to label by 50\%, when compared to
random sampling.


title:
Delay-Optimal Scheduling and Power Control for
  Instantaneous-Interference-Limited CRs

abstract:
  We study an uplink multi secondary user (SU) cognitive radio system suffering
statistical heterogeneity among SUs' channels. This heterogeneity may result in
differentiated delay performances to these SUs and result in harmful
interference to the PU. We first derive an explicit closed-form expression for
the average delay in terms of an arbitrary power-control policy. Then, we
propose a delay-optimal closed-form scheduling and power-control policy that
can provide the required average delay guarantees to all SUs besides protecting
the PU from harmful interference. We support our findings by extensive system
simulations and show that it outperforms existing policies substantially.


title:
Strong and Anisotropic Third Harmonic Generation in Monolayer and
  Multilayer ReS$_2$

abstract:
  We report observation of strong and anisotropic third harmonic generation
(THG) in monolayer and multilayer ReS$_2$. The third-order nonlinear optical
susceptibility of monolayer ReS$_2$, $\left| \chi^{(3)} \right|$ is on the
order of $10^{-18} $ m$^2$/V$^2$, which is about one order of magnitude higher
than reported results for hexagonal-lattice transition metal dichalcogenides
such as MoS$_2$. A similar magnitude for the third-order nonlinear optical
susceptibility was also obtained for a multilayer sample. The intensity of the
THG field was found to be dependent on the direction of the incident light
polarization for both monolayer and multilayer samples. A point group symmetry
analysis shows that such anisotropy is not expected from a perfect $1T$
lattice, and must arise from the distortions in the ReS$_2$ lattice. Our
results show that THG measurements can be used to characterize lattice
distortions of two-dimensional materials, and that lattice distortions are
important for the nonlinear optical properties of such materials.


title: Torsion points and Galois representations on CM elliptic curves

abstract:
  We prove several results on torsion points and Galois representations for
complex multiplication (CM) elliptic curves over a number field containing the
CM field. One result computes the degree in which such an elliptic curve has a
rational point of order $N$, refining results of Silverberg. Another result
bounds the size of the torsion subgroup of an elliptic curve with CM by a
nonmaximal order in terms of the torsion subgroup of an elliptic curve with CM
by the maximal order. Our techniques also yield a complete classification of
both the possible torsion subgroups and the rational cyclic isogenies of a
$K$-CM elliptic curve $E$ defined over $K(j(E))$.


title:
Integrability aspects of the vortex filament equation for pseudo-null
  curves

abstract:
  An algebraic background in order to study the integrability properties of
pseudo-null curve motions in a $3$-dimensional Lorentzian space form is
developed. As an application we delve into the relationship between the
Burgers' equation and the pseudo-null vortex filament equation. A recursion
operator for the pseudo-null vortex filament equation is also provided.


title:
A natural language interface to a graph-based bibliographic information
  retrieval system

abstract:
  With the ever-increasing scientific literature, there is a need on a natural
language interface to bibliographic information retrieval systems to retrieve
related information effectively. In this paper, we propose a natural language
interface, NLI-GIBIR, to a graph-based bibliographic information retrieval
system. In designing NLI-GIBIR, we developed a novel framework that can be
applicable to graph-based bibliographic information retrieval systems. Our
framework integrates algorithms/heuristics for interpreting and analyzing
natural language bibliographic queries. NLI-GIBIR allows users to search for a
variety of bibliographic data through natural language. A series of text- and
linguistic-based techniques are used to analyze and answer natural language
queries, including tokenization, named entity recognition, and syntactic
analysis. We find that our framework can effectively represents and addresses
complex bibliographic information needs. Thus, the contributions of this paper
are as follows: First, to our knowledge, it is the first attempt to propose a
natural language interface to graph-based bibliographic information retrieval.
Second, we propose a novel customized natural language processing framework
that integrates a few original algorithms/heuristics for interpreting and
analyzing natural language bibliographic queries. Third, we show that the
proposed framework and natural language interface provide a practical solution
in building real-world natural language interface-based bibliographic
information retrieval systems. Our experimental results show that the presented
system can correctly answer 39 out of 40 example natural language queries with
varying lengths and complexities.


title:
The Team Surviving Orienteers Problem: Routing Robots in Uncertain
  Environments with Survival Constraints

abstract:
  In this paper we study the following multi-robot coordination problem: given
a graph, where each edge is weighted by the probability of surviving while
traversing it, find a set of paths for $K$ robots that maximizes the expected
number of nodes collectively visited, subject to constraints on the probability
that each robot survives to its destination. We call this problem the Team
Surviving Orienteers (TSO) problem. The TSO problem is motivated by scenarios
where a team of robots must traverse a dangerous, uncertain environment, such
as aid delivery in disaster or war zones. We present the TSO problem formally
along with several variants, which represent "survivability-aware" counterparts
for a wide range of multi-robot coordination problems such as vehicle routing,
patrolling, and informative path planning. We propose an approximate greedy
approach for selecting paths, and prove that the value of its output is bounded
within a factor $1-e^{-p_s/\lambda}$ of the optimum where $p_s$ is the
per-robot survival probability threshold, and $1/\lambda \le 1$ is the
approximation factor of an oracle routine for the well-known orienteering
problem. Our approach has linear time complexity in the team size and
polynomial complexity in the graph size. Using numerical simulations, we verify
that our approach is close to the optimum in practice and that it scales to
problems with hundreds of nodes and tens of robots.


title:
New Tests of Uniformity on the Compact Classical Groups as Diagnostics
  for Weak-star Mixing of Markov Chains

abstract:
  This paper introduces two new families of non-parametric tests of
goodness-of-fit on the compact classical groups. One of them is a family of
tests for the eigenvalue distribution induced by the uniform distribution,
which is consistent against all fixed alternatives. The other is a family of
tests for the uniform distribution on the entire group, which is again
consistent against all fixed alternatives. We find the asymptotic distribution
under the null and general alternatives. The tests are proved to be
asymptotically admissible. Local power is derived and the global properties of
the power function against local alternatives are explored.
  The new tests are validated on two random walks for which the mixing-time is
studied in the literature. The new tests, and several others, are applied to
the Markov chain sampler proposed by \cite{jones2011randomized}, providing
strong evidence supporting the claim that the sampler mixes quickly.

categories: math.ST math.NA math.RT stat.CO stat.ME stat.TH


title: Introducing the Qplex: A Novel Arena for Quantum Theory

abstract:
  We reconstruct quantum theory starting from the premise that, as Asher Peres
remarked, "Unperformed experiments have no results." The tools of modern
quantum information theory, and in particular the symmetric informationally
complete (SIC) measurements, provide a concise expression of how exactly
Peres's dictum holds true. That expression is a constraint on how the
probability distributions for outcomes of different, mutually exclusive
experiments mesh together, a type of constraint not foreseen in classical
thinking. Taking this as our foundational principle, we show how to reconstruct
the formalism of quantum theory in finite-dimensional Hilbert spaces. Along the
way, we derive a condition for the existence of a d-dimensional SIC.


title:
Enhancing entropy and enthalpy fluctuations to drive crystallization in
  atomistic simulations

abstract:
  Crystallization is a process of great practical relevance in which rare but
crucial fluctuations lead to the formation of a solid phase starting from the
liquid. Like in all first order first transitions there is an interplay between
enthalpy and entropy. Based on this idea, to drive crystallization in molecular
simulations, we introduce two collective variables, one enthalpic and the other
entropic. Defined in this way, these collective variables do not prejudge the
structure the system is going to crystallize into. We show the usefulness of
this approach by studying the case of sodium and aluminum that crystallize in
the bcc and fcc crystalline structure, respectively. Using these two generic
collective variables, we perform variationally enhanced sampling and well
tempered metadynamics simulations, and find that the systems transform
spontaneously and reversibly between the liquid and the solid phases.


title:
Co-localization with Category-Consistent Features and Geodesic Distance
  Propagation

abstract:
  Co-localization is the problem of localizing objects of the same class using
only the set of images that contain them. This is a challenging task because
the object detector must be built without negative examples that can lead to
more informative supervision signals. The main idea of our method is to cluster
the feature space of a generically pre-trained CNN, to find a set of CNN
features that are consistently and highly activated for an object category,
which we call category-consistent CNN features. Then, we propagate their
combined activation map using superpixel geodesic distances for
co-localization. In our first set of experiments, we show that the proposed
method achieves state-of-the-art performance on three related benchmarks:
PASCAL 2007, PASCAL-2012, and the Object Discovery dataset. We also show that
our method is able to detect and localize truly unseen categories, on six
held-out ImageNet categories with accuracy that is significantly higher than
previous state-of-the-art. Our intuitive approach achieves this success without
any region proposals or object detectors and can be based on a CNN that was
pre-trained purely on image classification tasks without further fine-tuning.


title: Carbon-Rich Carbon Nitride Monolayers with Dirac Cones: Dumbbell C4N

abstract:
  Two-dimensional (2D) carbon nitride materials play an important role in
energy-harvesting, energy-storage and environmental applications. Recently, a
new carbon nitride, 2D polyaniline (C3N) was proposed [PNAS 113 (2016)
7414-7419]. Based on the structure model of this C3N monolayer, we propose two
new carbon nitride monolayers, named dumbbell (DB) C4N-I and C4N-II. Using
first-principles calculations, we systematically study the structure,
stability, and band structure of these two materials. In contrast to other
carbon nitride monolayers, the orbital hybridization of the C/N atoms in the DB
C4N monolayers is sp3. Remarkably, the band structures of the two DB C4N
monolayers have a Dirac cone at the K point and their Fermi velocities are
comparable to that of graphene. This makes them promising materials for
applications in high-speed electronic devices. Using a tight-binding model, we
explain the origin of the Dirac cone.


title:
Affordable, Rapid Bootstrapping of the Space Industry and Solar System
  Civilization

abstract:
  Advances in robotics and additive manufacturing have become game-changing for
the prospects of space industry. It has become feasible to bootstrap a
self-sustaining, self-expanding industry at reasonably low cost. Simple
modeling was developed to identify the main parameters of successful
bootstrapping. This indicates that bootstrapping can be achieved with as little
as 12 metric tons (MT) landed on the Moon during a period of about 20 years.
The equipment will be teleoperated and then transitioned to full autonomy so
the industry can spread to the asteroid belt and beyond. The strategy begins
with a sub-replicating system and evolves it toward full self-sustainability
(full closure) via an in situ technology spiral. The industry grows
exponentially due to the free real estate, energy, and material resources of
space. The mass of industrial assets at the end of bootstrapping will be 156 MT
with 60 humanoid robots, or as high as 40,000 MT with as many as 100,000
humanoid robots if faster manufacturing is supported by launching a total of 41
MT to the Moon. Within another few decades with no further investment, it can
have millions of times the industrial capacity of the United States. Modeling
over wide parameter ranges indicates this is reasonable, but further analysis
is needed. This industry promises to revolutionize the human condition.


title: When multiplicative noise stymies control

abstract:
  We consider the stabilization of an unstable discrete-time linear system that
is observed over a channel corrupted by continuous multiplicative noise. Our
main result shows that if the system growth is large enough, then the system
cannot be stabilized in a second-moment sense. This is done by showing that the
probability that the state magnitude remains bounded must go to zero with time.
Our proof technique recursively bounds the conditional density of the system
state (instead of focusing on the second moment) to bound the progress the
controller can make. This sidesteps the difficulty encountered in using the
standard data-rate theorem style approach; that approach does not work because
the mutual information per round between the system state and the observation
is potentially unbounded.
  It was known that a system with multiplicative observation noise can be
stabilized using a simple memoryless linear strategy if the system growth is
suitably bounded. In this paper, we show that while memory cannot improve the
performance of a linear scheme, a simple non-linear scheme that uses one-step
memory can do better than the best linear scheme.


title:
Impacts of Bad ESP (Early Size Predictions) on Software Effort
  Estimation

abstract:
  Context: Early size predictions (ESP) can lead to errors in effort
predictions for software projects. This problem is particular acute in
parametric effort models that give extra weight to size factors (for example,
the COCOMO model assumes that effort is exponentially proportional to project
size). Objective: To test if effort estimates are crippled by bad ESP. Method:
Document inaccuracies in early size estimates. Use those error sizes to
determine the implications of those inaccuracies via a Monte Carlo perturbation
analysis of effort models and an analysis of the equations used in those effort
models. Results: While many projects have errors in ESP of up to +/- 100%,
those errors add very little to the overall effort estimate error.
Specifically, we find no statistically significant difference in the estimation
errors seen after increasing ESP errors from 0 to +/- 100%. An analysis of
effort estimation models explains why this is so: the net additional impact of
ESP error is relatively small compared to the other sources of error associated
with in estimation models. Conclusion: ESP errors effect effort estimates by a
relatively minor amount. As soon as a model uses a size estimate and other
factors to predict project effort, then ESP errors are not crippling to the
process of estimation


title:
Eigenvalue estimates of minimal hypersurfaces with finite index in
  Riemannian manifolds

abstract:
  The purpose of this paper is to study a complete orientable minimal
hypersurface with finite index in an $(n+1)$-dimensional Riemannian manifold
$N$. We generalize Theorems 1.5-1.6 (\cite{Seo14}). In 1976, Schoen and Yau
proved the Liouville type theorem on stable minimal hypersurface, i.e., Theorem
1.7 (\cite{SchoenYau1976}). Recently, Seo (\cite{Seo14}) generalized Theorem
1.7 (\cite{SchoenYau1976}). Finally, we generalize Theorems 1.7
(\cite{SchoenYau1976}) and 1.8 (\cite{Seo14})


title:
StackGAN: Text to Photo-realistic Image Synthesis with Stacked
  Generative Adversarial Networks

abstract:
  Synthesizing high-quality images from text descriptions is a challenging
problem in computer vision and has many practical applications. Samples
generated by existing text-to-image approaches can roughly reflect the meaning
of the given descriptions, but they fail to contain necessary details and vivid
object parts. In this paper, we propose Stacked Generative Adversarial Networks
(StackGAN) to generate 256x256 photo-realistic images conditioned on text
descriptions. We decompose the hard problem into more manageable sub-problems
through a sketch-refinement process. The Stage-I GAN sketches the primitive
shape and colors of the object based on the given text description, yielding
Stage-I low-resolution images. The Stage-II GAN takes Stage-I results and text
descriptions as inputs, and generates high-resolution images with
photo-realistic details. It is able to rectify defects in Stage-I results and
add compelling details with the refinement process. To improve the diversity of
the synthesized images and stabilize the training of the conditional-GAN, we
introduce a novel Conditioning Augmentation technique that encourages
smoothness in the latent conditioning manifold. Extensive experiments and
comparisons with state-of-the-arts on benchmark datasets demonstrate that the
proposed method achieves significant improvements on generating photo-realistic
images conditioned on text descriptions.


title:
Statistical State Dynamics of Vertically Sheared Horizontal Flows in
  Two-Dimensional Stratified Turbulence

abstract:
  Simulations of strongly stratified turbulence often exhibit coherent
large-scale structures called vertically sheared horizontal flows (VSHFs).
VSHFs emerge in both two-dimensional (2D) and three-dimensional (3D) stratified
turbulence with similar vertical structure. The mechanism responsible for VSHF
formation is not fully understood. In this work, the formation and
equilibration of VSHFs in a 2D Boussinesq model of stratified turbulence is
studied using statistical state dynamics (SSD). In SSD, equations of motion are
expressed directly in the statistical variables of the turbulent state.
Restriction to 2D turbulence makes available an analytically and
computationally attractive implementation of SSD referred to as S3T, in which
the SSD is expressed by coupling the equation for the horizontal mean structure
with the equation for the ensemble mean perturbation covariance. This second
order SSD produces accurate statistics, through second order, when compared
with fully nonlinear simulations. In particular, S3T captures the spontaneous
emergence of the VSHF and associated density layers seen in simulations of
turbulence maintained by homogeneous large-scale stochastic excitation. An
advantage of the S3T system is that the VSHF formation mechanism, which is
wave-mean flow interaction between the emergent VSHF and the stochastically
excited large-scale gravity waves, is analytically understood in the S3T
system. Comparison with fully nonlinear simulations verifies that S3T solutions
accurately predict the scale selection, dependence on stochastic excitation
strength, and nonlinear equilibrium structure of the VSHF. These results
facilitate relating VSHF theory and geophysical examples of turbulent jets such
as the ocean's equatorial deep jets.


title: Chiral edge fluctuations of colloidal membranes

abstract:
  We study edge fluctuations of a flat colloidal membrane comprised of a
monolayer of aligned filamentous viruses. Experiments reveal that a peak in the
spectrum of the in-plane edge fluctuations arises for sufficiently strong virus
chirality. Accounting for internal liquid crystalline degrees of freedom by the
length, curvature, and geodesic torsion of the edge, we calculate the spectrum
of the edge fluctuations. The theory quantitatively describes the experimental
data, demonstrating that chirality couples in-plane and out-of-plane edge
fluctuations to produce the peak.


title: Self-sustained micromechanical oscillator with linear feedback

abstract:
  Autonomous oscillators, such as clocks and lasers, produce periodic signals
\emph{without} any external frequency reference. In order to sustain stable
periodic motions, there needs to be external energy supply as well as
nonlinearity built into the oscillator to regulate the amplitude. Usually,
nonlinearity is provided by the sustaining feedback mechanism, which also
supplies energy, whereas the constituent resonator that determines the output
frequency stays linear. Here we propose a new self-sustaining scheme that
relies on the nonlinearity originating from the resonator itself to limit the
oscillation amplitude, while the feedback remains linear. We introduce a model
to describe the working principle of the self-sustained oscillations and
validate it with experiments performed on a nonlinear microelectromechanical
(MEMS) based oscillator.


title: Algorithms for Visibility-Based Monitoring with Robot Teams

abstract:
  We study the problem of planning paths for a team of robots for visually
monitoring an environment. Our work is motivated by surveillance and persistent
monitoring applications. We are given a set of target points in a polygonal
environment that must be monitored using robots with cameras. The goal is to
compute paths for all robots such that every target is visible from at least
one path. In its general form, this problem is NP-hard as it generalizes the
Art Gallery Problem and the Watchman Route Problem. We study two versions: (i)
a geometric version in \emph{street polygons} for which we give a polynomial
time $4$--approximation algorithm; and (ii) a general version for which we
present a practical solution that finds the optimal solution in possibly
exponential time. In addition to theoretical proofs, we also present results
from simulation studies.


title:
Parameter Estimation of a Nonlinear Burgers Model using Nanoindentation
  and Finite Element-based Inverse Analysis

abstract:
  Nanoindentation involves probing a hard diamond tip into a material, where
the load and the displacement experienced by the tip is recorded continuously.
This load-displacement data is a direct function of material's innate
stress-strain behavior. Thus, theoretically it is possible to extract
mechanical properties of a material through nanoindentation. However, due to
various nonlinearities associated with nanoindentation the process of
interpreting load-displacement data into material properties is difficult.
Although, simple elastic behavior can be characterized easily, a method to
characterize complicated material behavior such as nonlinear viscoelasticity is
still lacking. In this study, a nanoindentation-based material characterization
technique is developed to characterize soft materials exhibiting nonlinear
viscoelasticity. Nanoindentation experiment was modeled in finite element
analysis software (ABAQUS), where a nonlinear viscoelastic behavior was
incorporated using user-defined subroutine (UMAT). The model parameters were
calibrated using a process called inverse analysis. In this study, a surrogate
model-based approach was used for the inverse analysis. The different factors
affecting the surrogate model performance are analyzed in order to optimize the
performance with respect to the computational cost.


title: Entropy of Kerr-de Sitter black hole

abstract:
  Based on the consideration that the black hole horizon and the cosmological
horizon of Kerr-de Sitter black hole are not independent each other, we
conjecture the total entropy of the system should have an extra term
contributed from the correlations between the two horizons, except for the sum
of the two horizon entropies. By employing globally effective first law and
effective thermodynamic quantities, we obtain the corrected total entropy and
find that the region of stable state for kerr-de Sitter is related to the
angular velocity parameter $a$, i.e., the region of stable state becomes bigger
as the rotating parameters $a$ is increases.


title: Polarization squeezing in polarized light

abstract:
  It is shown that polarized light can be polarization squeezed only if it
exhibits sub-Poissonian statistics with the Mandel's Q factor less than -1/2.


title: Electronic zero-point fluctuation forces inside circuit components

abstract:
  One of the most intriguing manifestations of quantum zero-point fluctuations
are the van der Waals and Casimir forces, often associated with vacuum
fluctuations of the electromagnetic field. Here we study generalized
fluctuation potentials acting on internal degrees of freedom of components in
electrical circuits. These electronic Casimir-like potentials are induced by
the zero-point current fluctuations of any general conductive circuit. For
realistic examples of an electromechanical capacitor and a superconducting
qubit, our results reveal the possibility of tunable forces between the
capacitor plates, or the level shifts of the qubit, respectively. Our analysis
suggests an alternative route towards the exploration of Casimir-like
fluctuation potentials, namely, by characterizing and measuring them as a
function of parameters of the environment. Such tunable potentials may be
useful for future nanoelectromechanical and quantum technologies.


title:
Large Polarization Squeezing in Non-Degenerate Parametric Amplification
  of Coherent Radiation

abstract:
  Polarization squeezing is shown to occur in non-degenerate parametric
amplification of coherent light and the degree of squeezing at interaction time
$T$ can be as large as $1-e^{-2T}$. This gives $86.4\%$ polarization squeezing
for $T=1$ and $98.2\%$ for $T=2$. One simple case when this occurs is on taking
initially plane polarized light having equal amplitudes in the two modes that
finally has equal intensities of two circular polarizations. This suggest the
experimental settings of parameters to achieve this extent of polarization
squeezing in coherent light.


title:
Nonlinear excitation of fine-radial-scale zonal structures by toroidal
  Alfven eigenmode

abstract:
  The set of equations describing nonlinear evolution of a single toroidal
Alfven eigenmode are derived, including both zero frequency zonal structure
(ZFZS) generation and wave-particle phase space nonlinearities. The simplified
case of neglecting wave-particle phase space nonlinearity is then investigated
to focus on different roles of energetic particles and bulk plasmas on ZFZS
generation. It is shown that energetic particles and bulk plasma play dominant
roles in ZFZS generation in different nonlinear stages, and the corresponding
processes are qualitatively different. Several properties of ZFZS generation,
e.g., fine- vs. meso-scale, forced driven vs. spontaneous excitation, are
clarified by the present analysis.


title:
Edge state preparation in one dimensional lattice by quantum Lyapunov
  control

abstract:
  Quantum Lyapunov control uses a feedback control methodology to determine
control fields which are applied to control quantum systems in an open-loop
way. In this work, we adopt two Lyapunov control schemes to prepare an edge
state for a fermionic chain consisted of cold atoms loaded in an optical
lattice. Such a chain can be described by the Harper model. Corresponding to
the two schemes, state distance and state error Lyapunov functions are
considered. The results show that both the schemes are effective to prepare the
edge state within a wide range of parameters. We found that the edge state can
be prepared with high fidelity even \textbf{if} there are moderate fluctuations
in on-site or hopping potentials. Both control schemes can be extended to
similar chains (3$m+d$, $d$=2) of different lengths. Since regular amplitude
control field is easier to apply in practice, amplitude-modulated control
fields are used to replace the unmodulated one to prepare the edge state. Such
control approaches provide tools to explore edge states for one dimensional
topological materials.


title: Optimal potentials for diffusive search strategies

abstract:
  We consider one dimensional diffusive search strategies subjected to external
potentials. The location of a single target is drawn from a given probability
density function (PDF) $f_G(x)$ and is fixed for each stochastic realization of
the process. We optimize the quality of the search strategy as measured by the
mean first passage time (MFPT) to the position of the target. For a symmetric
but otherwise arbitrary distribution $f_G(x)$ we find the optimal potential
that minimizes the MFPT. The minimal MFPT is given by a nonstandard measure of
the dispersion, which can be related to the cumulative R\'enyi entropy. We
compare optimal times in this model with optimal times obtained for the model
of diffusion with stochastic resetting, in which the diffusive motion is
interrupted by intermittent jumps (resets) to the initial position.
Additionally, we discuss an analogy between our results and a so-called
square-root principle.


title:
An efficient method for removing point sources from full-sky radio
  interferometric maps

abstract:
  A new generation of wide-field radio interferometers designed for 21-cm
surveys is being built as drift scan instruments allowing them to observe large
fractions of the sky. With large numbers of antennas and frequency channels the
enormous instantaneous data rates of these telescopes require novel, efficient,
data management and analysis techniques. The $m$-mode formalism exploits the
periodicity of such data with the sidereal day, combined with the assumption of
statistical isotropy of the sky, to achieve large computational savings and
render optimal analysis methods computationally tractable. We present an
extension to that work that allows us to adopt a more realistic sky model and
treat objects such as bright point sources. We develop a linear procedure for
deconvolving maps, using a Wiener filter reconstruction technique, which
simultaneously allows filtering of these unwanted components. We construct an
algorithm, based on the Sherman-Morrison-Woodbury formula, to efficiently
invert the data covariance matrix, as required for any optimal signal-to-noise
weighting. The performance of our algorithm is demonstrated using simulations
of a cylindrical transit telescope.


title:
Modulation Doping of Silicon using Aluminium-induced Acceptor States in
  Silicon Dioxide

abstract:
  All electronic, optoelectronic or photovoltaic applications of silicon depend
on controlling majority charge carriers via doping with impurity atoms.
Nanoscale silicon is omnipresent in fundamental research (quantum dots,
nanowires) but also approached in future technology nodes of the
microelectronics industry. In general, silicon nanovolumes, irrespective of
their intended purpose, suffer from effects that impede conventional doping due
to fundamental physical principles such as out-diffusion, statistics of small
numbers, quantum- or dielectric confinement. In analogy to the concept of
modulation doping, originally invented for III-V semiconductors, we demonstrate
a heterostructure modulation doping method for silicon. Our approach utilizes a
specific acceptor state of aluminium atoms in silicon dioxide to generate holes
as majority carriers in adjacent silicon. By relocating the dopants from
silicon to silicon dioxide, Si nanoscale doping problems are circumvented. In
addition, the concept of aluminium-induced acceptor states for passivating hole
selective tunnelling contacts as required for high-efficiency photovoltaics is
presented and corroborated by first carrier lifetime measurements.


title:
Models as Approximations II: A Model-Free Theory of Parametric
  Regression

abstract:
  We develop a model-free theory of general types of parametric regression for
iid observations. The theory replaces the parameters of parametric models with
statistical functionals, to be called "regression functionals'', defined on
large non-parametric classes of joint $\xy$ distributions, without assuming a
correct model. Parametric models are reduced to heuristics to suggest plausible
objective functions. An example of a regression functional is the vector of
slopes of linear equations fitted by OLS to largely arbitrary $\xy$
distributions, without assuming a linear model (see Part~I). More generally,
regression functionals can be defined by minimizing objective functions or
solving estimating equations at joint $\xy$ distributions. In this framework it
is possible to achieve the following: (1)~define a notion of well-specification
for regression functionals that replaces the notion of correct specification of
models, (2)~propose a well-specification diagnostic for regression functionals
based on reweighting distributions and data, (3)~decompose sampling variability
of regression functionals into two sources, one due to the conditional response
distribution
  and another due to the regressor distribution interacting with
misspecification, both of order $N^{-1/2}$, (4)~exhibit plug-in/sandwich
estimators of standard error as limit cases of $\xy$ bootstrap estimators, and
(5)~provide theoretical heuristics to indicate that $\xy$ bootstrap standard
errors may generally be more stable than sandwich estimators.


title:
Density phase separation and order-disorder transition in a collection
  of polar self-propelled particles

abstract:
  We study the order-disorder transition in a collection of polar
self-propelled particles, interacting through a distance dependent short range
alignment interaction. A distance dependent interaction parameter $a_0$ is
introduced such that on decreasing $a_0$ interaction decay faster with distance
$d$ and for $a_0=1.0$ model reduces to Vicsek's type. For all $a_0>0.0$, system
shows a transition from disorder to long ranged ordered state. We find another
phase transition from phase separated to nonphase separated state with
decreasing $a_0$: at the same time order-disorder transition changes from
discontinuous to continuous type. Hence density phase separation plays an
important role in predicting the nature of order-disorder transition. We also
calculate the two-point density structure factor using coarse-grained
hydrodynamic equations of motion with an introduction of a density dependent
alignment term in the equation introduced by Toner and Tu \cite{tonertu}.
Density structure factor shows a divergence at a critical wave-vector $q_c$,
which decreases with decreasing density dependent alignment term. Alignment
term in the coarse-grained equation plays the same role as the distance
dependent parameter $a_0$ in the microscopic simulation. Our results can be
tested in many biological systems: where particle have tendency to interact
strongly with their closest neighbours.


title: Light incoherence due to background space fluctuations

abstract:
  Working by analogy, we use the description of light fluctuations due to
random collisions of the radiating atoms to figure out why the reduction of the
coherence for light propagating a cosmological distance in the fluctuating
background space is negligibly small to be observed by the stellar
interferometry.


title: Chaos and regularity in the doubly magic nucleus 208Pb

abstract:
  High resolution experiments have recently lead to a complete identification
(energy, spin, and parity) of 151 nuclear levels up to an excitation Energy of
Ex= 6.20 MeV in 208Pb. We present a thorough study of the fluctuation
properties in the energy spectra of the unprecedented set of nuclear bound
states. In a first approach we grouped states with the same spin and parity
into 14 subspectra, analyzed standard statistical measures for short- and
long-range correlations and then computed their ensemble average. Their
comparison with a random matrix ensemble which interpolates between Poisson
statistics expected for regular systems and the Gaussian Orthogonal Ensemble
(GOE) predicted for chaotic systems shows that the data are well described by
the GOE. In a second approach, following an idea of Rosenzweig and Porter we
considered the complete spectrum composed of the independent subspectra. We
analyzed their fluctuation properties using the method of Bayesian inference
involving a quantitative measure, called the chaoticity parameter f, which also
interpolates between Poisson (f=0) and GOE statistics (f=1). It turns out to be
f~0.9. This is so far the closest agreement with GOE observed in spectra of
bound states in a nucleus. The same analysis has also been performed with
spectra computed on the basis of shell model calculations with different
interactions (SDI, KB, M3Y). While the simple SDI exhibits features typical for
nuclear many-body systems with regular dynamics, the other, more realistic
interactions yield chaoticity parameters f close to the experimental values.


title: Photon Blockade in Two-Emitter-Cavity Systems

abstract:
  The photon blockade (PB) effect in emitter-cavity systems depends on the
anharmonicity of the ladder of dressed energy eigenstates. The recent
developments in color center photonics are leading toward experimental
demonstrations of multi-emitter-cavity solid-state systems with an expanded set
of energy levels compared to the traditionally studied single-emitter systems.
We focus on the case of N = 2 nonidentical quasi-atoms strongly coupled to a
nanocavity in the bad cavity regime (with parameters within reach of the color
center systems), and discover three PB mechanisms: polaritonic, subradiant and
unconventional. The polaritonic PB, which is the conventional mechanism studied
in single-emitter-cavity systems, also occurs at the polariton frequencies in
multi-emitter systems. The subradiant PB is a new interference effect owing to
the inhomogeneous broadening of the emitters which results in a purer and a
more robust single photon emission than the polaritonic PB. The unconventional
PB in the modeled system corresponds to the suppression of the single- and
two-photon correlation statistics and the enhancement of the three-photon
correlation statistic. Using the effective Hamiltonian approach, we unravel the
origin and the time-domain evolution of these phenomena.


title: Finite dimensional Hopf algebras over Kac-Paljutkin algebra $H_8$

abstract:
  Let $H_8$ be the neither commutative nor cocommutative semisimple eight
dimensional Hopf algebra, which is also called Kac-Paljutkin algebra
\cite{MR0208401}. All simple Yetter-Drinfel'd modules over $H_8$ are given. As
for simple objects and direct sums of two simple objects in
${}_{H_8}^{H_8}\mathcal{YD}$, we calculated dimensions for the corresponding
Nichols algebras, except four semisimple cases which are generally difficult.
Under the assumption that the four undetermined Nichols algebras are all
infinite dimensional, we determine all the finite dimensional Nichols algebras
over $H_8$. It turns out that the already known finite dimensional Nichols
algebras are all diagonal type. In fact, they are Cartan types $A_1$, $A_2$,
$A_2\times A_2$, $A_1\times \cdots \times A_1$, and $A_1\times \cdots \times
A_1\times A_2$. By the way, we calculate Gelfand-Kirillov dimensions for some
Nichols algebras. As an application, we obtain five families of new finite
dimensional Hopf algebras over $H_8$ according to the lifting method.


title: Programmable optical waveform reshaping on a picosecond timescale

abstract:
  We experimentally demonstrate temporal reshaping of optical waveforms in the
telecom wavelength band using the principle of quantum frequency conversion.
The reshaped optical pulses do not undergo any wavelength translation. The
interaction takes place in a nonlinear $\chi^{(2)}$ waveguide using an
appropriately designed pump pulse programmed via an optical waveform generator.
We show reshaping of a single-peak pulse into a double-peak pulse and vice
versa. We also show that exponentially decaying pulses can be reshaped into
near Gaussian shape, and vice versa, which is a useful functionality for
quantum communications.