title:
Localization transition in random Levy matrices : multifractality of
  eigenvectors in the localized phase and at criticality

abstract:
  For random L\'evy matrices of size $N \times N$, where matrix elements are
drawn with some heavy-tailed distribution $P(H_{ij}) \propto N^{-1} |H_{ij}
|^{-1-\mu}$ with $0<\mu<2$ (infinite variance), there exists an extensive
number of finite eigenvalues $E=O(1)$, while the maximal eigenvalue grows as
$E_{max} \sim N^{\frac{1}{\mu}}$. Here we study the localization properties of
the corresponding eigenvectors via some strong disorder perturbative expansion
that remains consistent within the localized phase and that yields their
Inverse Participation Ratios (I.P.R.) $Y_q$ as a function of the continuous
parameter $0<q<+\infty$. In the region $0<\mu<1$, we find that all eigenvectors
are localized but display some multifractality : the IPR are finite above some
threshold $q>q_c$ but diverge in the region $0<q<q_c$ near the origin. In the
region $1<\mu<2$, only the sub-extensive fraction $N^{\frac{3}{2+\mu}}$ of the
biggest eigenvalues corresponding to the region $| E| \geq
N^{\frac{(\mu-1)}{\mu(2+\mu)}} $ remains localized, while the extensive number
of other states of smaller energy are delocalized. For the extensive number of
finite eigenvalues $E=O(1)$, the localization/delocalization transition thus
takes place at the critical value $\mu_c=1$ corresponding to Cauchy matrices :
the Inverse Participation Ratios $Y_q$ of the corresponding critical
eigenstates follow the Strong-Multifractality Spectrum characterized by the
generalized fractal dimensions $D^{criti}(q) = \frac{1-2q}{1-q} \theta (0 \leq
q \leq \frac{1}{2})$, which has been found previously in various other
Localization problems in spaces of effective infinite dimensionality.


title:
On Frame Asynchronous Coded Slotted ALOHA: Asymptotic, Finite Length,
  and Delay Analysis

abstract:
  We consider a frame asynchronous coded slotted ALOHA (FA-CSA) system for
uncoordinated multiple access, where users join the system on a slot-by-slot
basis according to a Poisson random process and, in contrast to standard frame
synchronous CSA (FS-CSA), users are not frame-synchronized. We analyze the
performance of FA-CSA in terms of packet loss rate and delay. In particular, we
derive the (approximate) density evolution that characterizes the asymptotic
performance of FA-CSA when the frame length goes to infinity. We show that, if
the receiver can monitor the system before anyone starts transmitting, a
boundary effect similar to that of spatially-coupled codes occurs, which
greatly improves the iterative decoding threshold. Furthermore, we derive tight
approximations of the error floor (EF) for the finite frame length regime,
based on the probability of occurrence of the most frequent stopping sets. We
show that, in general, FA-CSA provides better performance in both the EF and
waterfall regions as compared to FS-CSA. Moreover, FA-CSA exhibits better delay
properties than FS-CSA.


title:
Ho\v{r}ava-Lifshitz gravity inspired Bianchi-II cosmology and the
  mixmaster universe

abstract:
  We study different aspects of the Ho\v{r}ava-Lifshitz inspired Bianchi-II
cosmology and its relations with the mixmaster universe model. First, we
present exact solutions for a toy model, where only the cubic in spatial
curvature terms are present in the action; then we briefly discuss some exotic
singularities, which can appear in this toy model. We study also the toy model
where only the quadratic in spatial curvature terms are present in the action.
We establish relations between our results and those obtained by using the
Hamiltonian formalism. Finally, we apply the results obtained by studying
Bianchi-II cosmology to describe the evolution of the mixmaster universe in
terms of the Belinsky-Khalatnikov-Lifshitz formalism. Generally, our analysis
gives some arguments in favour of the existence of the oscillatory approach to
the singularity in a universe governed by the Ho\v{r}ava-Lifshitz type gravity.


title: Simple epistemic planning: generalised gossiping

abstract:
  The gossip problem, in which information (known as secrets) must be shared
among a certain number of agents using the minimum number of calls, is of
interest in the conception of communication networks and protocols. We extend
the gossip problem to arbitrary epistemic depths. For example, we may require
not only that all agents know all secrets but also that all agents know that
all agents know all secrets. We give optimal protocols for various versions of
the generalised gossip problem, depending on the graph of communication links,
in the case of two-way communications, one-way communications and parallel
communication. We also study different variants which allow us to impose
negative goals such as that certain agents must not know certain secrets. We
show that in the presence of negative goals testing the existence of a
successful protocol is NP-complete whereas this is always polynomial-time in
the case of purely positive goals.


title:
Omission and Commission Errors in Network Cognition and Network
  Estimation using ROC Curve

abstract:
  Cognitive Social Structure (CSS) network studies collect relational data on
respondents' direct ties and their perception of ties among all other
individuals in the network. When reporting their perception networks,
respondents commit two types of errors, namely, omission (false negatives) and
commission (false positives) errors. We first assess the relationship between
these two error types, and their contributions on the overall respondent
accuracy. Next we propose a method for estimating networks based on perceptions
of a random sample of respondents from a bounded social network, which utilizes
the Receiving Operator Characteristic (ROC) curve for balancing the tradeoffs
between omission and commission errors. A comparative numerical study shows
that the proposed estimation method performs well. This new method can be
easily integrated to organization studies that use randomized surveys to study
multiple organizations. The burgeoning field of multilevel analysis of
inter-organizational networks can also immensely benefit from this approach.


title:
Drop tower setup for dynamic light scattering in dense gas-fluidized
  granular media

abstract:
  Investigation of dynamics in dense granular media is challenging. Here we
present a setup that facilitates gas fluidization of dense granular media in
microgravity. The dynamics is characterized using diffusing wave spectroscopy.
We demonstrate that agitated granular media reach a steady state within
fractions of a second in drop tower flights. The intensity autocorrelation
functions obtained in microgravity show a remarkable dependence on sample
volume fraction and driving strength. A plateau in correlation merges at low
volume fractions and strong driving, while correlation decays only very slowly
but continuously at high packing fractions. The setup allows to independently
set sample volume fraction and driving strength, and thus extends the
possibilities for investigations on dynamics in dense granular on ground.


title:
Universal properties of high temperature superconductors from real space
  pairing: t-J-U model and its quantitative comparison with experiment

abstract:
  Selected universal experimental properties of high temperature
superconducting (HTS) cuprates have been singled out in the last decade. One of
the pivotal challenges in this field is the designation of a consistent
interpretation framework within which we can describe quantitatively the
universal features of those systems. Here we analyze in a detailed manner the
principal experimental data and compare them quantitatively with the approach
based on a single band of strongly correlated electrons supplemented with
strong antiferromagnetic (super)exchange interaction (the so-called $t$-$J$-$U$
model). The model rationale is provided by estimating its macroscopic
parameters on the basis of the 3-band approach for the Cu-O plane. We use our
original full Gutzwiller-wave-function solution by going beyond the
renormalized mean field theory (RMFT) in a systematic manner. Our approach
reproduces very well the observed hole doping ($\delta$) dependence of the
kinetic-energy gain in the superconducting phase, one of the principal
non-Bardeen-Cooper-Schrieffer features of the cuprates. The calculated Fermi
velocity in the nodal direction is practically $\delta$-independent and its
universal value agrees very well with that determined experimentally. Also, a
weak doping dependence of the Fermi wave-vector leads to an almost constant
value of the effective mass in a pure superconducting phase which is both
observed in the experiment and reproduced within our approach. An assessment of
the currently used models is carried out and the results of the canonical RMFT
as a zeroth-order solution are provided for comparison to illustrate the
necessity of introduced higher order contributions.


title:
MAC: a novel systematically multilevel cache replacement policy for PCM
  memory

abstract:
  The rapid development of multi-core system and increase of data-intensive
application in recent years call for larger main memory. Traditional DRAM
memory can increase its capacity by reducing the feature size of storage cell.
Now further scaling of DRAM faces great challenge, and the frequent refresh
operations of DRAM can bring a lot of energy consumption. As an emerging
technology, Phase Change Memory (PCM) is promising to be used as main memory.
It draws wide attention due to the advantages of low power consumption, high
density and nonvolatility, while it incurs finite endurance and relatively long
write latency. To handle the problem of write, optimizing the cache replacement
policy to protect dirty cache block is an efficient way. In this paper, we
construct a systematically multilevel structure, and based on it propose a
novel cache replacement policy called MAC. MAC can effectively reduce write
traffic to PCM memory with low hardware overhead. We conduct simulation
experiments on GEM5 to evaluate the performances of MAC and other related
works. The results show that MAC performs best in reducing the amount of writes
(averagely 25.12%) without increasing the program execution time.


title:
Evidence for interfacial superconductivity in a bi-collinear
  antiferromagnetically ordered FeTe monolayer on a topological insulator

abstract:
  The discovery of high-temperature superconductivity in Fe-based compounds
[1,2] has triggered numerous investigations on the interplay between
superconductivity and magnetism [3] and, more recently, on the enhancement of
transition temperatures through interface effects [4]. It is widely believed
that the emergence of optimal superconductivity is intimately linked to the
suppression of long-range antiferromagnetic (AFM) order, although the exact
microscopic picture of this relationship remains elusive [1] due to the lack of
data with atomic spatial resolution [5-7]. Here, we present a spin-polarized
scanning tunneling spectroscopy (SP-STS) study of ultrathin FeTe$_{1-x}$Se$_x$
(x = 0, 0.5) films grown on prototypical Bi-based bulk topological insulators.
Surprisingly, we find an energy gap at the Fermi level indicating
superconducting correlations up to Tc ~ 6 K for one unit cell thin FeTe layers
grown on Bi2Te3 substrates, in contrast to the non-superconducting FeTe bulk
compound [8]. Moreover, SP-STS reveals that the energy gap spatially coexists
with bicollinear AFM order. This finding opens novel perspectives for
theoretical studies of competing orders in Fe-based superconductors as well as
for experimental investigations of exotic phases in heterostructures of
topological insulators and superconducting layers.


title: HYDRO + JETS (HYDJET++) event generator for Pb+Pb collisions at LHC

abstract:
  The Monte Carlo event generator HYDJET++ is one of the few generators,
designed for the calculations of heavy-ion collisions at ultrarelativistic
energies, which combine treatment of soft hydro-like processes with the
description of jets traversing the hot and dense partonic medium. The model is
employed to study the azimuthal anisotropy phenomena, dihadron angular
correlations and event-by-event (EbyE) fluctuations of the anisotropic flow in
Pb+Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV. The interplay of soft and hard
processes describes the violation of the mass hierarchy of meson and baryon
elliptic and triangular flows at p_T > 2 GeV/c, the fall-off of the flow
harmonics at intermediate transverse momenta, and the worsening of the
number-of-constituent-quark (NCQ) scaling of elliptic/triangular flow at LHC
compared to RHIC energies. The cross-talk of v_2 and v_3 leads to emergence of
higher order harmonics in the model and to appearance of the ridge structure in
dihadron angular correlations in a broad pseudorapidity range. HYDJET++
possesses also the dynamical EbyE fluctuations of the anisotropic flow. The
model results agree well with the experimental data.


title:
On the determination of sets supporting unknown sources for the wave
  equation from radiated fields

abstract:
  Given near or far field wave measurements generated by some unknown time- and
space-dependent acoustic source, we seek to rapidly determine a domain in
space-time, as small as possible, that contains the support of a source
radiating these measurements. As for any inverse source problem, this task is
challenging without further restrictions on the source, particularly due to the
infinite-dimensional space of silent sources radiating zero measurements. This
first causes non-uniqueness, that is, the source in general cannot be
determined uniquely, and second prevents the computation of, e. g., a largest
set that must contain the support of the source. To determine small domains
containing the support of some source that radiates given measurements, we
exploit that solutions to the wave equation propagate along characteristics. We
further indicate restrictions on the support of a source that allow to
theoretically characterize this support uniquely from near or far field
measurements.


title:
Birational geometry of del Pezzo fibrations with terminal quotient
  singularities

abstract:
  Del Pezzo fibrations appear as minimal models of rationally connected
varieties. The rationality of smooth del Pezzo fibrations is a well studied
question but smooth fibrations are not dense in moduli. Little is known about
the rationality of the singular models. We prove birational rigidity, hence
non-rationality, of del Pezzo fibrations with simple non-Gorenstein
singularities satisfying the famous $K^2$-condition. We then apply this result
to study embeddings of $\operatorname{PSL}_2(7)$ into the Cremona group.


title:
Perturbation analysis in thermodynamics using matrix representations of
  Ruelle transfer operators

abstract:
  We study perturbations of topological pressures, Gibbs measures and
measure-theoretic entropies of these measures concerning perturbed potentials
defined on topologically transitive subshift of finite type. The subshift with
respect to non-perturbed system is assumed to be no topologically transitive.
Therefore, the subshift of the perturbed systems and the subshift of the
unperturbed system are different. We reduce this situation to a perturbation
problem of certain irreducible nonnegative matrices generated by Ruelle
transfer operators. Consequently, under suitable conditions of potentials, we
characterize the limit points of those thermodynamics and give a necessary and
sufficient condition for convergence of Gibbs measures and the
measure-theoretic entropy of this measure when the subshift of the
non-perturbed system has $2$ or $3$ transitive components with the maximal
pressure. Finally, we illustrate the relation between potentials and
convergence of Gibbs measures by using asymptotic expansion techniques for
eigenvalues of Ruelle transfer operators.


title:
Natural Language Generation enhances human decision-making with
  uncertain information

abstract:
  Decision-making is often dependent on uncertain data, e.g. data associated
with confidence scores or probabilities. We present a comparison of different
information presentations for uncertain data and, for the first time, measure
their effects on human decision-making. We show that the use of Natural
Language Generation (NLG) improves decision-making under uncertainty, compared
to state-of-the-art graphical-based representation methods. In a task-based
study with 442 adults, we found that presentations using NLG lead to 24% better
decision-making on average than the graphical presentations, and to 44% better
decision-making when NLG is combined with graphics. We also show that women
achieve significantly better results when presented with NLG output (an 87%
increase on average compared to graphical presentations).


title: Fast evaluation of real and complex exponential sums

abstract:
  Recently, the butterfly approximation scheme and hierarchical approximations
have been proposed for the efficient computation of integral transforms with
oscillatory and with asymptotically smooth kernels. Combining both approaches,
we propose a certain fast Fourier-Laplace transform, which in particular allows
for the fast evaluation of polynomials at nodes in the complex unit disk. All
theoretical results are illustrated by numerical experiments.


title: Combinatorial results implied by many zero divisors in a group ring

abstract:
  It has been recently proved (by Croot, Lev and Pach and the subsequent work
by Ellenberg and Gijswijt) that for a group $G=G_0^n$, where $G_0\ne
\{1,-1\}^m$ is a fixed finite Abelian group and $n$ is large, any subset $A$
without 3-progressions (triples $x,y,z$ of different elements with $xy=z^2$)
contains at most $|G|^{1-c}$ elements, where $c>0$ is a constant depending only
on $G_0$. This is known to be false when $G$ is, say, large cyclic group. The
aim of this note is to show that algebraic property which corresponds to this
difference is the following: in the first case a group algebra $\mathbb{F}[G]$
over suitable field $\mathbb{F}$ contains a subspace $X$ with codimension at
most $|X|^{1-c}$ such that $X^3=0$. We discuss which bounds are obtained for
finite Abelian $p$-groups and for some matrix $p$-groups: Heisenberg group over
$\mathbb{F}_p$ and the unitriangular group over $\mathbb{F}_p$. Also we show
how the method works for further generalizations by Kleinberg--Sawin--Speyer
and Ellenberg.


title: Certified domination

abstract:
  Imagine that we are given a set $D$ of officials and a set $W$ of civils. For
each civil $x \in W$, there must be an official $v \in D$ that can serve $x$,
and whenever any such $v$ is serving $x$, there must also be another civil $w
\in W$ that observes $v$, that is, $w$ may act as a kind of witness, to avoid
any abuse from $v$. What is the minimum number of officials to guarantee such a
service, assuming a given social network?
  In this paper, we introduce the concept of certified domination that
perfectly models the aforementioned problem. Specifically, a dominating set $D$
of a graph $G=(V_G,E_G)$ is said to be certified if every vertex in $D$ has
either zero or at least two neighbours in $V_G\setminus D$. The cardinality of
a minimum certified dominating set in $G$ is called the certified domination
number of $G$. Herein, we present the exact values of the certified domination
number for some classes of graphs as well as provide some upper bounds on this
parameter for arbitrary graphs. We then characterise a wide class of graphs
with equal domination and certified domination numbers and characterise graphs
with large values of certified domination numbers. Next, we examine the effects
on the certified domination number when the graph is modified by
deleting/adding an edge or a vertex. We also provide Nordhaus-Gaddum type
inequalities for the certified domination number. Finally, we show that the
(decision) certified domination problem is NP-complete.


title:
An improved radial basis-pseudospectral method with hybrid
  Gaussian-cubic kernels

abstract:
  While pseudospectral (PS) methods can feature very high accuracy, they tend
to be severely limited in terms of geometric flexibility. Application of global
radial basis functions overcomes this, however at the expense of problematic
conditioning (1) in their most accurate flat basis function regime, and (2)
when problem sizes are scaled up to become of practical interest. The present
study considers a strategy to improve on these two issues by means of using
hybrid radial basis functions that combine cubic splines with Gaussian kernels.
The parameters, controlling Gaussian and cubic kernels in the hybrid RBF, are
selected using global particle swarm optimization. The proposed approach has
been tested with radial basis-pseudospectral method for numerical approximation
of Poisson, Helmholtz, and Transport equation. It was observed that the
proposed approach significantly reduces the ill-conditioning problem in the
RBF-PS method, at the same time, it preserves the stability and accuracy for
very small shape parameters. The eigenvalue spectra of the coefficient matrices
in the improved algorithm were found to be stable even at large degrees of
freedom, which mimic those obtained in pseudospectral approach. Also, numerical
experiments suggest that the hybrid kernel performs significantly better than
both pure Gaussian and pure cubic kernels.


title: New Upper Bounds for Equiangular Lines by Pillar Decomposition

abstract:
  We derive a procedure for computing an upper bound on the number of
equiangular lines in various Euclidean vector spaces by generalizing the
classical pillar decomposition developed by (Lemmens and Seidel, 1973); namely,
we use linear algebra and combinatorial arguments to bound the number of
vectors within an equiangular set which have inner products of certain signs
with a negative clique. After projection and rescaling, such sets are also
certain spherical two-distance sets, and semidefinite programming techniques
may be used to bound the size. Applying our method, we prove new relative
bounds for the angle arccos(1/5). Experiments show that our relative bounds for
all possible angles are considerably less than the known SDP bounds for a range
of larger dimension r. Our computational results also show an explicit bound on
the size of a set of equiangular lines regardless of angle, which is strictly
less than the well-known Gerzon's bound if r+2 is not a square of an odd
number.


title: MPA for TASEP with a generalized update on a ring

abstract:
  We apply the Matrix Product Ansatz to study the Totally Asymmetric Simple
Exclusion Process on a ring with a generalized discrete-time dynamics depending
on two hopping probabilities, $p$ and $\tilde{p}$. The model contains as
special cases the TASEP with parallel update, when $\tilde{p} =0$, and with
sequential backward-ordered update, when $\tilde{p} =p$.
  We construct a two-dimensional matrix-product representation and use it to
obtain exact finite-size expressions for the partition function, the current of
particles and the two-point correlation function. Our main new result is the
derivation of the finite-size pair correlation function. Its behavior is
analyzed in different regimes of effective attraction and repulsion between the
particles, depending on whether $\tilde{p} >p$ or $\tilde{p} < p$. In
particular, we explicitly obtain an analytic expression for the pair
correlation function in the limit of irreversible aggregation
$\tilde{p}\rightarrow 1$, when the stationary configurations contain just one
cluster.


title: Socio-economic inequality: Relationship between Gini and Kolkata indices

abstract:
  Socio-economic inequality is characterized from data using various indices.
The Gini ($g$) index, giving the overall inequality is the most common one,
while the recently introduced Kolkata ($k$) index gives a measure of $1-k$
fraction of population who possess top $k$ fraction of wealth in the society.
Here, we show the relationship between the two indices, using both empirical
data and analytical estimates. The significance of their relationship has been
discussed.


title:
Thermal quenches in the stochastic Gross-Pitaevskii equation: morphology
  of the vortex network

abstract:
  We study the evolution of 3d weakly interacting bosons at finite chemical
potential with the stochastic Gross-Pitaevskii equation. We fully characterise
the vortex network in an out of equilibrium. At high temperature the filament
statistics are the ones of fully-packed loop models. The vortex tangle
undergoes a geometric percolation transition within the thermodynamically
ordered phase. After infinitely fast quenches across the thermodynamic critical
point deep into the ordered phase, we identify a first approach towards the
critical percolation state, a later coarsening process that does not alter the
fractal properties of the long vortex loops, and a final approach to
equilibrium. Our results are also relevant to the statistics of linear defects
in type II superconductors, magnetic materials and cosmological models.


title:
Stationary increments harmonizable stable fields: upper estimates on
  path behaviour

abstract:
  Studying sample path behaviour of stochastic fields/processes is a classical
research topic in probability theory and related areas such as fractal
geometry. To this end, many methods have been developed since a long time in
Gaussian frames. They often rely on some underlying "nice" Hilbertian
structure, and can also require finiteness of moments of high order. Therefore,
they can hardly be transposed to frames of heavy-tailed stable probability
distributions. However, in the case of some linear non-anticipative moving
average stable fields/processes, such as the linear fractional stable sheet and
the linear multifractional stable motion, rather new wavelet strategies have
already proved to be successful in order to obtain sharp moduli of continuity
and other results on sample path behaviour. The main goal of our article is to
show that, despite the difficulties inherent in the frequency domain, such kind
of a wavelet methodology can be generalized and improved, so that it also
becomes fruitful in a general harmonizable stable setting with stationary
increments. Let us point out that there are large differences between this
harmonizable setting and the moving average stable one.


title:
Short channel effects in graphene-based field effect transistors
  targeting radio-frequency applications

abstract:
  Channel length scaling in graphene field effect transistors (GFETs) is key in
the pursuit of higher performance in radio frequency electronics for both rigid
and flexible substrates. Although two-dimensional (2D) materials provide a
superior immunity to Short Channel Effects (SCEs) than bulk materials, they
could dominate in scaled GFETs. In this work, we have developed a model that
calculates electron and hole transport along the graphene channel in a
drift-diffusion basis, while considering the 2D electrostatics. Our model
obtains the self-consistent solution of the 2D Poisson's equation coupled to
the current continuity equation, the latter embedding an appropriate model for
drift velocity saturation. We have studied the role played by the
electrostatics and the velocity saturation in GFETs with short channel lengths
L. Severe scaling results in a high degradation of GFET output conductance. The
extrinsic cutoff frequency follows a 1/L^n scaling trend, where the index n
fulfills n < 2. The case n = 2 corresponds to long-channel GFETs with low
source/drain series resistance, that is, devices where the channel resistance
is controlling the drain current. For high series resistance, n decreases down
to n= 1, and it degrades to values of n < 1 because of the SCEs, especially at
high drain bias. The model predicts high maximum oscillation frequencies above
1 THz for channel lengths below 100 nm, but, in order to obtain these
frequencies, it is very important to minimize the gate series resistance. The
model shows very good agreement with experimental current voltage curves
obtained from short channel GFETs and also reproduces negative differential
resistance, which is due to a reduction of diffusion current.


title:
Searching for neutrino oscillation parameters in long baseline
  experiments

abstract:
  Developing neutrino astronomy requires a good understanding of the neutrino
oscillations mechanism. The European strategy for neutrino oscillation physics
sets a high priority on future long baseline neutrino experiments with the aim
to measure the intrinsic parameters that govern the neutrino oscillations. In
this work we take a look at the next generation of long baseline experiments
and discuss their prospects in future research.


title: Watch out for This Commit! A Study of Influential Software Changes

abstract:
  One single code change can significantly influence a wide range of software
systems and their users. For example, 1) adding a new feature can spread
defects in several modules, while 2) changing an API method can improve the
performance of all client programs. Developers often may not clearly know
whether their or others' changes are influential at commit time. Rather, it
turns out to be influential after affecting many aspects of a system later.
This paper investigates influential software changes and proposes an approach
to identify them early, i.e., immediately when they are applied. We first
conduct a post-mortem analysis to discover existing influential changes by
using intuitions such as isolated changes and changes referred by other changes
in 10 open source projects. Then we re-categorize all identified changes
through an open-card sorting process. Subsequently, we conduct a survey with 89
developers to confirm our influential change categories. Finally, from our
ground truth we extract features, including metrics such as the complexity of
changes, terms in commit logs and file centrality in co-change graphs, to build
machine learning classifiers. The experiment results show that our prediction
model achieves overall with random samples 86.8% precision, 74% recall and
80.4% F-measure respectively.


title: Quantum-enhanced microscopy with binary-outcome photon counting

abstract:
  Polarized light microscopy using path-entangled $N$-photon states (i.e., the
N00N states) has been demonstrated to surpass the shot-noise limit at very low
light illumination. However, the microscopy images suffer from divergence of
phase sensitivity, which inevitably reduces the image quality. Here, we show
that due to experimental imperfections, such a singularity also takes place in
the microscopy that uses twin-Fock states of light for illumination. We propose
two schemes to completely eliminate this singularity: (i) locking the phase
shift sensed by the beams at the optimal working point, by using a spatially
dependent offset phase; (ii) a combination of two binary-outcome photon
counting measurements, one with a fixed offset phase and the other without any
offset phase. Our observations remain valid for any kind of binary-outcome
measurement and may open the way for quantum-enhanced microscopy with high $N$
photon states.


title:
Parameterized Algorithmics for Graph Modification Problems: On
  Interactions with Heuristics

abstract:
  In graph modification problems, one is given a graph G and the goal is to
apply a minimum number of modification operations (such as edge deletions) to G
such that the resulting graph fulfills a certain property. For example, the
Cluster Deletion problem asks to delete as few edges as possible such that the
resulting graph is a disjoint union of cliques. Graph modification problems
appear in numerous applications, including the analysis of biological and
social networks. Typically, graph modification problems are NP-hard, making
them natural candidates for parameterized complexity studies. We discuss
several fruitful interactions between the development of fixed-parameter
algorithms and the design of heuristics for graph modification problems,
featuring quite different aspects of mutual benefits.


title: Collinearly improved JIMWLK evolution in Langevin form

abstract:
  The high-energy evolution of Wilson line operators, which at leading order is
described by the Balitsky-JIMWLK equations, receives large radiative
corrections enhanced by single and double collinear logarithms at
next-to-leading order and beyond. We propose a method for resumming such
logarithmic corrections to all orders, at the level of the Langevin formulation
of the JIMWLK equation. The ensuing, collinearly-improved Langevin equation
features generalized Wilson line operators, which depend not only upon rapidity
(the logarithm of the longitudinal momentum), but also upon the transverse size
of the color neutral projectile to which the Wilson lines belong. This
additional scale dependence is built up during the evolution, via the condition
that the successive emissions of soft gluons be ordered in time. The presence
of this transverse scale in the Langevin equation furthermore allows for the
resummation of the one-loop running coupling corrections.


title:
Stable and unstable periodic orbits in the one dimensional lattice
  $\phi^4$ theory

abstract:
  Periodic orbits for the classical $\phi^4$ theory on the one dimensional
lattice are systematically constructed by extending the normal modes of the
harmonic theory, for periodic, fixed and free boundary conditions. Through the
process, we clarify, in general, which normal modes of the linear theory can or
can not be extended to the full non-linear theory. We then analyze the
stability of these orbits, clarifying the link between the stability,
parametric resonance and the Lyapunov spectra for these orbits.The construction
of the periodic orbits and the stability analysis is applicable to theories
governed by Hamiltonians with quadratic inter-site potentials and a general
on-site potential. We also apply the analysis to theories with on-site
potentials that have qualitatively different behavior from the $\phi^4$ theory,
with some concrete examples.


title:
The perturbed universe in the deformed algebra approach of Loop Quantum
  Cosmology

abstract:
  Loop quantum cosmology is a tentative approach to model the universe down to
the Planck era where quantum gravity settings are needed. The quantization of
the universe as a dynamical space-time is inspired by Loop Quantum Gravity
ideas. In addition, loop quantum cosmology could bridge contact with
astronomical observations, and thus potentially investigate quantum cosmology
modellings in the light of observations. To do so however, modelling both the
background evolution and its perturbations is needed. The latter describe
cosmic inhomogeneities that are the main cosmological observables. In this
context, we present the so-called deformed algebra approach implementing the
quantum corrections to the perturbed universe at an effective level by taking
great care of gauge issues. We particularly highlight that in this framework,
the algebra of hypersurface deformation receives quantum corrections, and we
discuss their meaning. The primordial power spectra of scalar and tensor
inhomogeneities are then presented, assuming initial conditions are set in the
contracting phase preceding the quantum bounce and the well-known expanding
phase of the cosmic history. These spectra are subsequently propagated to
angular power spectra of the anisotropies of the cosmic microwave background.
It is then shown that regardless of the choice for the initial conditions
inside the effective approach for the background evolution (except that they
are set in the contracting phase), the predicted angular power spectra of the
polarized B-modes exceed the upper bound currently set by observations. The
exclusion of this specific version of loop quantum cosmology establishes the
falsifiability of the approach, though one shall not conclude here that either
loop quantum cosmology or loop quantum gravity is excluded.


title:
Fourier multiplier theorems on Besov spaces under type and cotype
  conditions

abstract:
  In this paper we consider Fourier multiplier operators between vector-valued
Besov spaces with different integrability exponents $p$ and $q$, which depend
on the type $p$ and cotype $q$ of the underlying Banach spaces. In a previous
paper we considered $L^p$-$L^q$-multiplier theorems. In the current paper we
show that in the Besov scale one can obtain results with optimal integrability
exponents. Moreover, we derive a sharp result in the $L^p$-$L^q$-setting as
well.
  We consider operator-valued multipliers without smoothness assumptions. The
results are based on a Fourier multiplier theorem for functions with compact
Fourier support. If the multiplier has smoothness properties then the
boundedness of the multiplier operator extrapolates to other values of $p$ and
$q$ for which $\frac1p - \frac1q$ remains constant.


title: On the algebraic area of lattice walks and the Hofstadter model

abstract:
  We consider the generating function of the algebraic area of lattice walks,
evaluated at a root of unity, and its relation to the Hofstadter model. In
particular, we obtain an expression for the generating function of the n-th
moments of the Hofstadter Hamiltonian in terms of a complete elliptic integral,
evaluated at a rational function. This in turn gives us both exact and
asymptotic formulas for these moments.


title: Effect of Gd/Nd doping on the magnetic properties of PrMnO3

abstract:
  A study on temperature dependent magnetic properties of single phase
orthorhombic perovskites system associated with space group Pbnm compounds
Pr1-x(Gd/Nd)xMnO3 (x=0.3, 0.5, 0.7) was carried out. A magnetization reversal
is observed below the Neel temperature (TN), in DC magnetization measurements
(at 50 Oe) in the doped compounds. This may be due to the antiparallel coupling
between the two magnetic sublattices (|Pr+Gd/Nd | and Mn). With lowering of
temperature, the |Pr+ Gd/Nd|) ions begin to polarize under the negative
internal field due to canted moment of Mn moments. The hysteresis plot taken at
50K shows a ferrimagnetic characteristic and the presence of spin canting of
ions in the magnetic sublattices. Arrott plot indicates field induced second
order paramagnetic to ferrimagnetic (PM-FiM) phase transition in this system.


title:
Analysis of the maximal posterior partition in the Dirichlet Process
  Gaussian Mixture Model

abstract:
  Mixture models are a natural choice in many applications, but it can be
difficult to place an a priori upper bound on the number of components. To
circumvent this, investigators are turning increasingly to Dirichlet process
mixture models (DPMMs). It is therefore important to develop an understanding
of the strengths and weaknesses of this approach. This work considers the MAP
(maximum a posteriori) clustering for the Gaussian DPMM (where the cluster
means have Gaussian distribution and, for each cluster, the observations within
the cluster have Gaussian distribution). Some desirable properties of the MAP
partition are proved: `almost disjointness' of the convex hulls of clusters
(they may have at most one point in common) and (with natural assumptions) the
comparability of sizes of those clusters that intersect any fixed ball with the
number of observations (as the latter goes to infinity). Consequently, the
number of such clusters remains bounded. Furthermore, if the data arises from
independent identically distributed sampling from a given distribution with
bounded support then the asymptotic MAP partition of the observation space
maximises a function which has a straightforward expression, which depends only
on the within-group covariance parameter. As the operator norm of this
covariance parameter decreases, the number of clusters in the MAP partition
becomes arbitrarily large, which may lead to the overestimation of the number
of mixture components.


title: An Application of Network Lasso Optimization For Ride Sharing Prediction

abstract:
  Ride sharing has important implications in terms of environmental, social and
individual goals by reducing carbon footprints, fostering social interactions
and economizing commuter costs. The ride sharing systems that are commonly
available lack adaptive and scalable techniques that can simultaneously learn
from the large scale data and predict in real-time dynamic fashion. In this
paper, we study such a problem towards a smart city initiative, where a generic
ride sharing system is conceived capable of making predictions about ride share
opportunities based on the historically recorded data while satisfying
real-time ride requests. Underpinning the system is an application of a
powerful machine learning convex optimization framework called Network Lasso
that uses the Alternate Direction Method of Multipliers (ADMM) optimization for
learning and dynamic prediction. We propose an application of a robust and
scalable unified optimization framework within the ride sharing case-study. The
application of Network Lasso framework is capable of jointly optimizing and
clustering different rides based on their spatial and model similarity. The
prediction from the framework clusters new ride requests, making accurate price
prediction based on the clusters, detecting hidden correlations in the data and
allowing fast convergence due to the network topology. We provide an empirical
evaluation of the application of ADMM network Lasso on real trip record and
simulated data, proving their effectiveness since the mean squared error of the
algorithm's prediction is minimized on the test rides.


title:
Millimeter-sized grains in the protostellar envelopes: where do they
  come from?

abstract:
  Grain growth during star formation affects the physical and chemical
processes in the evolution of star-forming clouds. We investigate the origin of
the millimeter (mm)-sized grains recently observed in Class I protostellar
envelopes. We use the coagulation model developed in our previous paper and
find that a hydrogen number density of as high as $10^{10}~{\rm cm^{-3}}$,
instead of the typical density $10^5~{\rm cm^{-3}}$, is necessary for the
formation of mm-sized grains. Thus, we test a hypothesis that such large grains
are transported to the envelope from the inner, denser parts, finding that gas
drag by outflow efficiently "launches" the large grains as long as the central
object has not grown to $\gtrsim 0.1$ M$_{\odot}$. By investigating the
shattering effect on the mm-sized grains, we ensure that the large grains are
not significantly fragmented after being injected in the envelope. We conclude
that the mm-sized grains observed in the protostellar envelopes are not formed
in the envelopes but formed in the inner parts of the star-forming regions and
transported to the envelopes before a significant mass growth of the central
object, and that they survive in the envelopes.


title:
Erupting filaments with large enclosing flux tubes as sources of
  high-mass 3-part CMEs, and erupting filaments in the absence of enclosing
  flux tubes as sources of low-mass unstructured CMEs

abstract:
  The 3-part appearance of many CMEs arising from erupting filaments emerges
from a large magnetic flux tube structure, consistent with the form of the
erupting filament system. Other CMEs arising from erupting filaments lack a
clear 3-part structure and reasons for this have not been researched in detail.
This paper aims to further establish the link between CME structure and the
structure of the erupting filament system and to investigate whether CMEs which
lack a 3-part structure have different eruption characteristics. A survey is
made of 221 near-limb filament eruptions observed from 2013/05/03-2014/06/30 by
EUV imagers and coronagraphs. 92 filament eruptions are associated with 3-part
structured CMEs, 41 eruptions are associated with unstructured CMEs. The
remaining 88 are categorized as failed eruptions. For 34% of the 3-part CMEs,
processing applied to EUV images reveals the erupting front edge is a
pre-existing loop structure surrounding the filament, which subsequently erupts
with the filament to form the leading bright front edge of the CME. This
connection is confirmed by a flux-rope density model. Furthermore, the
unstructured CMEs have a narrower distribution of mass compared to structured
CMEs, with total mass comparable to the mass of 3-part CME cores. This study
supports the interpretation of 3-part CME leading fronts as the outer
boundaries of a large pre-existing flux tube. Unstructured (non 3-part) CMEs
are a different family to structured CMEs, arising from the eruption of
filaments which are compact flux tubes in the absence of a large system of
enclosing closed field.


title:
High throughput thermal conductivity of high temperature solid phases:
  The case of oxide and fluoride perovskites

abstract:
  Using finite-temperature phonon calculations and machine-learning methods, we
calculate the mechanical stability of about 400 semiconducting oxides and
fluorides with cubic perovskite structures at 0 K, 300 K and 1000 K. We find 92
mechanically stable compounds at high temperatures -- including 36 not
mentioned in the literature so far -- for which we calculate the thermal
conductivity. We demonstrate that the thermal conductivity is generally smaller
in fluorides than in oxides, largely due to a lower ionic charge, and describe
simple structural descriptors that are correlated with its magnitude.
Furthermore, we show that the thermal conductivities of most cubic perovskites
decrease more slowly than the usual $T^{-1}$ behavior. Within this set, we also
screen for materials exhibiting negative thermal expansion. Finally, we
describe a strategy to accelerate the discovery of mechanically stable
compounds at high temperatures.


title: Optimal control of forward-backward stochastic Volterra equations

abstract:
  We study the problem of optimal control of a coupled system of
forward-backward stochastic Volterra equations. We use Hida-Malliavin calculus
to prove a sufficient and a necessary maximum principle for the optimal control
of such systems. Existence and uniqueness of backward stochastic Volterra
integral equations are proved. As an application of our methods, we solve a
recursive utility optimisation problem in a financial model with memory.


title: Turning a coin over instead of tossing it

abstract:
  Given a sequence of numbers $\{p_n\}$ in $[0,1]$, consider the following
experiment. First, we flip a fair coin and then, at step $n$, we turn the coin
over to the other side with probability $p_n$, $n\ge 2$. What can we say about
the distribution of the empirical frequency of heads as $n\to\infty$?
  We show that a number of phase transitions take place as the turning gets
slower (i.e. $p_n$ is getting smaller), leading first to the breakdown of the
Central Limit Theorem and then to that of the Law of Large Numbers. It turns
out that the critical regime is $p_n=\text{const}/n$. Among the scaling limits,
we obtain Uniform, Gaussian, Semicircle and Arcsine laws.


title: Finding Horndeski theories with Einstein gravity limits

abstract:
  The Horndeski action is the most general scalar-tensor theory with at most
second-order derivatives in the equations of motion, thus evading Ostrogradsky
instabilities and making it of interest when modifying gravity at large scales.
To pass local tests of gravity, these modifications predominantly rely on
nonlinear screening mechanisms that recover Einstein's Theory of General
Relativity in regions of high density. We derive a set of conditions on the
four free functions of the Horndeski action that examine whether a specific
model embedded in the action possesses an Einstein gravity limit or not. For
this purpose, we develop a new and surprisingly simple scaling method that
identifies dominant terms in the equations of motion by considering formal
limits of the couplings that enter through the new terms in the modified
action. This enables us to find regimes where nonlinear terms dominate and
Einstein's field equations are recovered to leading order. Together with an
efficient approximation of the scalar field profile, one can then further
evaluate whether these limits can be attributed to a genuine screening effect.
For illustration, we apply the analysis to both a cubic galileon and a
chameleon model as well as to Brans-Dicke theory. Finally, we emphasise that
the scaling method also provides a natural approach for performing
post-Newtonian expansions in screened regimes.


title:
Finite-temperature Wigner solid and other phases of ripplonic polarons
  on a helium film

abstract:
  Electrons on liquid helium can form different phases depending on density,
and temperature. Also the electron-ripplon coupling strength influences the
phase diagram, through the formation of so-called "ripplonic polarons", that
change how electrons are localized, and that shifts the transition between the
Wigner solid and the liquid phase. We use an all-coupling, finite-temperature
variational method to study the formation of a ripplopolaron Wigner solid on a
liquid helium film for different regimes of the electron-ripplon coupling
strength. In addition to the three known phases of the ripplopolaron system
(electron Wigner solid, polaron Wigner solid, and electron fluid), we define
and identify a fourth distinct phase, the ripplopolaron liquid. We analyse the
transitions between these four phases and calculate the corresponding phase
diagrams. This reveals a reentrant melting of the electron solid as a function
of temperature. The calculated regions of existence of the Wigner solid are in
agreement with recent experimental data.


title: The Complex Lagrangian Germ and the Canonical Operator

abstract:
  We give a manifestly invariant definition of the Lagrangian complex germ with
the minimal degree of accuracy required to define the canonical operator. The
equivalence with the traditional definition is proved, and the canonical
operator is constructed in new terms. A new form of the quantization condition
is given, in which the volume form is assumed to be defined on the universal
covering of the Lagrangian manifold rather than on the manifold itself. This
allows one to solve a wider class of eigenvalue problems.


title: Lightning detection in planetary atmospheres

abstract:
  Lightning in planetary atmospheres is now a well-established concept. Here we
discuss the available detection techniques for, and observations of, planetary
lightning by spacecraft, planetary landers and, increasingly, sophisticated
terrestrial radio telescopes. Future space missions carrying lightning-related
instrumentation are also summarised, specifically the European ExoMars mission
and Japanese Akatsuki mission to Venus, which could both yield lightning
observations in 2016.


title: Localization for Dirac fermions

abstract:
  This work is devoted to incorporating into QFT the notion that particles and
hence the particle states should be localizable in space. It focuses on the
case of the Dirac field in 1+1 dimensional flat spacetime, generalizing a
recently developed formalism for scalar fields. This is achieved exploiting
again the non-uniqueness of quantization process. Instead of elementary
excitations carrying definite amounts of energy and momentum, we construct the
elementary excitations of the field localized (at some instant) in a definite
region of space. This construction not only leads to a natural notion of
localized quanta, but also provides a local algebra of operators. Once
constructed, the new representation is confronted to the standard global (Fock)
construction. In spite of being unitarily inequivalent representations, the
localized operators are well defined in the conventional Fock space. By using
them we dig up the issues of localization in QFT showing how the globality of
the vacuum state is responsible for the lack of a "common sense localization"
notion for particles in the standard Fock representation of QFT and propose a
method to meet its requirements.


title: Chiral Relaxation Time at the Crossover of Quantum Chromodynamics

abstract:
  We study microscopic processes responsible for chirality flips in the thermal
bath of Quantum Chromodynamics at finite temperature and zero baryon chemical
potential. We focus on the temperature range where the crossover from chirally
broken phase to quark-gluon plasma takes place, namely $T \simeq (150, 200)$
MeV. The processes we consider are quark-quark scatterings mediated by
collective excitations with the quantum number of pions and $\sigma$-meson,
hence we refer to these processes simply as \sugg{to} one-pion (one-$\sigma$)
exchange\sugg{s}. We use a Nambu-Jona-Lasinio model to compute equilibrium
properties of the thermal bath, as well as the relevant scattering kernel to be
used in the collision integral to estimate the chiral relaxation time $\tau$.
We find $\tau\simeq 0.1 \div 1$ fm/c around the chiral crossover.


title: Soft Particle Production in Very High Energy Hadron Interactions

abstract:
  Indications of a discrepancy between simulations and data on the number of
muons in cosmic ray (CR) showers exist over a large span of energies. We focus
in particular on the excess of multi-muon bundles observed by the DELPHI
detector at LEP and on the excess in the muon number in general reported by the
Pierre Auger Observatory. Even though the primary CR energies relevant for
these experiments differ by orders of magnitude, we can find a single mechanism
which can simultaneously increase predicted muon counts for both, while not
violating constraints from accelerators or from the longitudinal shower
development as observed by the Pierre Auger Observatory. We present a brief
theoretical motivation and describe a practical implementation of such a model,
based on the addition of soft particles to interactions above a chosen energy
threshold. Results of an extensive set of simulations show the behavior of this
model in various parts of a simplified parameter space.


title: Tunable Online MUS/MSS Enumeration

abstract:
  In various areas of computer science, the problem of dealing with a set of
constraints arises. If the set of constraints is unsatisfiable, one may ask for
a minimal description of the reason for this unsatisifi- ability. Minimal
unsatisifable subsets (MUSes) and maximal satisifiable subsets (MSSes) are two
kinds of such minimal descriptions. The goal of this work is the enumeration of
MUSes and MSSes for a given constraint system. As such full enumeration may be
intractable in general, we focus on building an online algorithm, which
produces MUSes/MSSes in an on-the-fly manner as soon as they are discovered.
The problem has been studied before even in its online version. However, our
algorithm uses a novel approach that is able to outperform current state-of-the
art algorithms for online MUS/MSS enumeration. Moreover, the performance of our
algorithm can be adjusted using tunable parameters. We evaluate the algorithm
on a set of benchmarks.


title: Linear systems on irregular varieties

abstract:
  Let $X$ be a normal complex projective variety, $T\subseteq X$ a subvariety,
$a\colon X\rightarrow A$ a morphism to an abelian variety such that
$\rm{Pic}^0(A)$ injects into $\rm{Pic}^0(T)$ and let $L$ be a line bundle on
$X$.
  Denote by $X^{(d)}\to X$ the connected \'etale cover induced by the $d$-th
multiplication map of $A$, by $T^{(d)} \subseteq X^{(d)}$ the preimage of $T$
and by $L^{(d)}$ the pull-back of $L$ to $X^{(d)}$. For $\alpha\in
\rm{Pic}^0(A)$ general, we study the restricted linear system $|L^{(d)}\otimes
a^*\alpha|_{|T^{(d)}}$: if for some $d$ this gives a generically finite map
$\varphi^{(d)}$, we show that f $\varphi^{(d)}$ is independent of $\alpha$ or
$d$ sufficiently large and divisible, and is induced by the {\em eventual map}
$\varphi\colon T\to Z$ such that $a_{|T}$ factorizes through $\varphi$.
  The generic value $h^0_a(X_{|T}, L)$ of $h^0(X_{|T}, L\otimes\alpha)$ is
called the {\em (restricted) continuous rank.} We prove that if $M$ is the pull
back of an ample divisor of $A$, then $x\mapsto h^0_a(X_{|T}, L+xM)$ extends to
a continuous function of $x\in\mathbb{R}$, which is differentiable except
possibly at countably many points; when $X=T$ we compute the left derivative
explicitly.
  In the case when $X$ and $T$ are smooth, combining the above results we prove
Clifford-Severi type inequalities, i.e., geographical bounds of the form
$$\rm{vol}_{X|T}(L)\geq C(m) h^0_a(X_{|T},L),$$ where $C(m)={\mathcal O}(m!)$.


title:
Assessing Learning Outcomes in Middle-Division Classical Mechanics: The
  Colorado Classical Mechanics/Math Methods Instrument

abstract:
  Reliable and validated assessments of introductory physics have been
instrumental in driving curricular and pedagogical reforms that lead to
improved student learning. As part of an effort to systematically improve our
sophomore-level Classical Mechanics and Math Methods course (CM 1) at CU
Boulder, we have developed a tool to assess student learning of CM 1 concepts
in the upper-division. The Colorado Classical Mechanics/Math Methods Instrument
(CCMI) builds on faculty consensus learning goals and systematic observations
of student difficulties. The result is a 9-question open-ended post-test that
probes student learning in the first half of a two-semester classical mechanics
/ math methods sequence. In this paper, we describe the design and development
of this instrument, its validation, and measurements made in classes at CU
Boulder and elsewhere.


title: A model that underlies the Standard model

abstract:
  We assign the chiral fermion fields of the Standard model to triplets of
flavor (family, generation, horizontal) $SU(3)_f$ symmetry, for anomaly freedom
add one triplet of sterile right-handed neutrino fields, and gauge that
symmetry. First we demonstrate that the resulting quantum flavor $SU(3)_f$
dynamics completely spontaneously self-breaks: Both the Majorana masses of
sterile neutrinos and the masses of all eight flavor gluons come out
proportional to the $SU(3)_f$ scale $\Lambda$. Mixing of sterile neutrinos
yields new CP-violating phases needed for understanding the baryon asymmetry of
the Universe. Second, the $SU(3)_f$ dynamics with weak hypercharge radiative
corrections spontaneously generates the lepton and quark masses exponentially
suppressed with respect to $\Lambda$. Three active neutrinos come out as
Majorana particles extremely light by seesaw. The Goldstone theorem implies:
(i) The electroweak bosons $W$ and $Z$ acquire masses. (ii) There are three
axions, decent candidates for dark matter. Invisibility of the Weinberg-Wilczek
axion $a$ with mass $m_a \sim \rm m^2_{\pi}/\Lambda$ restricts the scale
$\Lambda$ from $\Lambda \sim \rm 10^{10} GeV$ upwards. Third, the composite
'would-be' Nambu-Goldstone (NG) bosons of all spontaneously broken gauge
symmetries have their {\it genuine composite} massive partners: (i) One $0^{+}$
flavorless Higgs-like particle $h$ accompanying three electroweak 'would-be' NG
bosons. (ii) Two $0^{+}$ flavored Higgs-like particles $h_3$ and $h_8$
accompanying six flavored electroweak 'would-be' NG bosons. (iii) Three
superheavy spin-zero sterile-neutrino-composites $\chi_i$ accompanying eight
flavored sterile-neutrino-composite 'would-be' NG bosons. We identify $\chi_i$
with inflatons.


title: Detection of CO and HCN in Pluto's atmosphere with ALMA

abstract:
  Observations of the Pluto-Charon system, acquired with the ALMA
interferometer on June 12-13, 2015, have yielded a detection of the CO(3-2) and
HCN(4-3) rotational transitions from Pluto, providing a strong confirmation of
the presence of CO, and the first observation of HCN, in Pluto's atmosphere.
The CO and HCN lines probe Pluto's atmosphere up to ~450 km and ~900 km
altitude, respectively. The CO detection yields (i) a much improved
determination of the CO mole fraction, as 515+/-40 ppm for a 12 ubar surface
pressure (ii) clear evidence for a well-marked temperature decrease (i.e.,
mesosphere) above the 30-50 km stratopause and a best-determined temperature of
70+/-2 K at 300 km, in agreement with recent inferences from New Horizons /
Alice solar occultation data. The HCN line shape implies a high abundance of
this species in the upper atmosphere, with a mole fraction >1.5x10-5 above 450
km and a value of 4x10-5 near 800 km. The large HCN abundance and the cold
upper atmosphere imply supersaturation of HCN to a degree (7-8 orders of
magnitude) hitherto unseen in planetary atmospheres, probably due to the slow
kinetics of condensation at the low pressure and temperature conditions of
Pluto's upper atmosphere. HCN is also present in the bottom ~100 km of the
atmosphere, with a 10-8 - 10-7 mole fraction; this implies either HCN
saturation or undersaturation there, depending on the precise stratopause
temperature. The HCN column is (1.6+/-0.4)x10^14 cm-2, suggesting a
surface-referred net production rate of ~2x10^7 cm-2s-1. Although HCN
rotational line cooling affects Pluto's atmosphere heat budget, the amounts
determined in this study are insufficient to explain the well-marked mesosphere
and upper atmosphere's ~70 K temperature. We finally report an upper limit on
the HC3N column density (< 2x10^13 cm-2) and on the HC15N / HC14N ratio (<
1/125).


title: Dynamic structure factor of the spin-1/2 XXZ chain in a transverse field

abstract:
  The spin-$\frac{1}{2}$ XXZ chain with easy-plane anisotropy in a transverse
field describes well the thermodynamic properties of the material ${\rm
Cs_2CoCl_4}$ in a wide range of temperatures and fields including the region
close to the spin-flop Ising quantum phase transition. For a comparison with
prospective inelastic neutron scattering experiments on this compound, we
present results of an extensive numerical study of its dynamic structure factor
$\mathcal{S}^{\alpha \beta}(k,\omega)$ using matrix-product-state (MPS)
techniques. Close to criticality, the dynamic part of the correlator
$\mathcal{S}^{xx}$ longitudinal to the applied field is incoherent and
possesses a small total weight as the ground state is already close to
saturation. The transverse correlator $\mathcal{S}^{zz}$, on the other hand, is
dominated by a coherent single-particle excitation with additional spectral
weight at higher energies that we tentatively attribute to a repulsively bound
pair of particles. With increasing temperature, the latter quickly fades and
spectral weight instead accumulates close to zero wavevector just above the
single-particle energy. On a technical level, we compare the numerical
efficiency of real-time evolution to an MPS-based Chebyshev expansion in the
present context, finding that both methods yield results of similar quality at
comparable numerical costs.


title: Simultaneous inference for misaligned multivariate functional data

abstract:
  We consider inference for misaligned multivariate functional data that
represents the same underlying curve, but where the functional samples have
systematic differences in shape. In this paper we introduce a new class of
generally applicable models where warping effects are modeled through nonlinear
transformation of latent Gaussian variables and systematic shape differences
are modeled by Gaussian processes. To model cross-covariance between sample
coordinates we introduce a class of low-dimensional cross-covariance structures
suitable for modeling multivariate functional data. We present a method for
doing maximum-likelihood estimation in the models and apply the method to three
data sets. The first data set is from a motion tracking system where the
spatial positions of a large number of body-markers are tracked in
three-dimensions over time. The second data set consists of height and weight
measurements for Danish boys. The third data set consists of three-dimensional
spatial hand paths from a controlled obstacle-avoidance experiment. We use the
developed method to estimate the cross-covariance structure, and use a
classification setup to demonstrate that the method outperforms
state-of-the-art methods for handling misaligned curve data.


title:
Relativistic quantum mechanical spin-1 wave equation in 2+1 dimensional
  spacetime

abstract:
  In this study, we introduce a relativistic quantum mechanical wave equation
of the spin-1 particle as an excited state of the zitterbewegung and show that
it is consistent with the 2+1 dimensional Proca theory. At the same time, we
see that in the rest frame this equation has two eigenstates, particle and
antiparticle states or negative and positive energy eigenstates, respectively,
and satisfy $SO(2,1)$ spin algebra. As practical applications, we derive the
exact solutions of the equation in the presence of a constant magnetic field
and a curved spacetime. From these solutions, we find Noether charge by
integrating the constructed spin-1 particle current on hyper surface and
discuss pair production from the charge. And, we see that the discussion on \
the Noether charge is useful tool for undersdantding the pair production
phenomenon because the charge is derived from a probabilistic particle current.


title: Precision physics in jet processes

abstract:
  We examine properties of small-radius jets, focusing on phenomenological
applications to the inclusive jet spectrum. We match fixed-order calculations
with the leading-logarithmic resummation of the jet radius (LL$_R$), and
propose a new prescription to evaluate theoretical uncertainties for
next-to-leading order (NLO) predictions. We also examine the $R$-dependent
next-to-next-to-leading order (NNLO) corrections, and include them in our
calculation. We discuss hadronisation corrections, which are derived from Monte
Carlo generators. Finally, we assemble these elements and compare the ratio of
the inclusive jet spectra at two $R$ values obtained from our matched
(N)NLO+LL$_R$ predictions to data from ALICE and ATLAS, finding improved
agreement.


title:
Structured Factored Inference: A Framework for Automated Reasoning in
  Probabilistic Programming Languages

abstract:
  Reasoning on large and complex real-world models is a computationally
difficult task, yet one that is required for effective use of many AI
applications. A plethora of inference algorithms have been developed that work
well on specific models or only on parts of general models. Consequently, a
system that can intelligently apply these inference algorithms to different
parts of a model for fast reasoning is highly desirable. We introduce a new
framework called structured factored inference (SFI) that provides the
foundation for such a system. Using models encoded in a probabilistic
programming language, SFI provides a sound means to decompose a model into
sub-models, apply an inference algorithm to each sub-model, and combine the
resulting information to answer a query. Our results show that SFI is nearly as
accurate as exact inference yet retains the benefits of approximate inference
methods.


title:
Universal relations of strongly interacting Fermi gases with multiple
  scattering channels

abstract:
  Universal relations are important for understanding strongly interacting
Fermi gases, the study of which have been mostly limited to cases with a single
scattering channel. Here we discover a series universal relations for strongly
interacting Fermi gases with multiple scattering channels. Unlike its
counterpart across a single channel wide magnetic Feshbach resonance, a new
kind of contact which we call the cross-channel contact naturally appears in
this system, this contact is related to varies thermodynamic quantities as well
as short range correlation functions.


title: Globular cluster-massive black hole interactions in galactic centers

abstract:
  Many, if not all, galaxies host massive compact objects at their centers.
They are present as singularities (super massive black holes) or high density
star clusters (nuclear tar clusters). In some cases they coexist, and interact
more or less strongly. In this short paper I will talk of the 'merger' globular
cluster scenario, which has been shown in the past to be an explanation of the
substantial mass accumulation in galactic centers. In particular, I will
present the many astrophysical implications of such scenario pointing the
attention on the mutual feedback of orbitally decaying globular clusters with
massive and super massive black holes.


title:
The eventual paracanonical map of a variety of maximal Albanese
  dimension

abstract:
  Let $X$ be a smooth complex projective variety such that the Albanese map of
$X$ is generically finite onto its image. Here we study the so-called eventual
$m$-paracanonical map of $X$ (when $m=1$ we also assume $\chi(K_X)>0$). We show
that for $m=1$ this map behaves in a similar way to the canonical map of a
surface of general type, while it is birational for $m>1$. We also describe it
explicitly in several examples.


title:
TransitLabel: A Crowd-Sensing System for Automatic Labeling of Transit
  Stations Semantics

abstract:
  We present TransitLabel, a crowd-sensing system for automatic enrichment of
transit stations indoor floorplans with different semantics like ticket vending
machines, entrance gates, drink vending machines, platforms, cars' waiting
lines, restrooms, lockers, waiting (sitting) areas, among others. Our key
observations show that certain passengers' activities (e.g., purchasing
tickets, crossing entrance gates, etc) present identifiable signatures on one
or more cell-phone sensors. TransitLabel leverages this fact to automatically
and unobtrusively recognize different passengers' activities, which in turn are
mined to infer their uniquely associated stations semantics. Furthermore, the
locations of the discovered semantics are automatically estimated from the
inaccurate passengers' positions when these semantics are identified. We
evaluate TransitLabel through a field experiment in eight different train
stations in Japan. Our results show that TransitLabel can detect the
fine-grained stations semantics accurately with 7.7% false positive rate and
7.5% false negative rate on average. In addition, it can consistently detect
the location of discovered semantics accurately, achieving an error within 2.5m
on average for all semantics. Finally, we show that TransitLabel has a small
energy footprint on cell-phones, could be generalized to other stations, and is
robust to different phone placements; highlighting its promise as a ubiquitous
indoor maps enriching service.


title:
Physical properties and the variability mechanism of the He I outflow in
  NGC 4151

abstract:
  We report on variable helium absorption lines in NGC 4151 observed across six
epochs of quasi-simultaneous near-infrared and optical data. These observations
cover the transitions from the metastable 2^3S state at 3889 A and 10830 A, and
from the 2^1S state at 20587 A. This is the first AGN absorption line
variability study to include measurements of the 20587 A line. The physical
properties of the absorber recorded at the fifth observational epoch are
relatively well constrained by the presence of absorption in both the optical
and near-infrared components, with the 10830 A line likely saturated. The
observations suggest variations in this absorber's strength are best explained
by ionization changes in response to a variable incident continuum.
Photoionization simulations constrain the total hydrogen number density of the
epoch 5 absorber to 7.1<log(n_H/cm^-3)<8.8, the hydrogen column density to
21.2<log(N_H/cm^-2)<23.3 and the ionization parameter range to -1.9<logU<0.4.
The simulations also suggest the absorber is located between 0.03 and 0.49 pc
from the continuum emission region. This range in physical properties is
consistent with an absorber of similar velocity seen in NGC 4151 from previous
ultraviolet and optical studies, but with high column density X-ray absorbing
components not present. The mass outflow rate due to the fifth epoch absorber
is in the range 0.008 to 0.38 M_sun/yr, too low to contribute to galaxy
feedback effects.


title: Homomorphic Evaluation of Database Queries

abstract:
  Homomorphic encryption is an encryption method that enables computing over
encrypted data. This has a wide range of real world ramifications such as being
able to blindly compute a search result sent to a remote server without
revealing its content. This paper discusses how database search queries can be
made secure using a homomorphic encryption scheme. We propose a new database
search technique that can be used with the ring-based fully homomorphic
encryption scheme proposed by Braserski.


title:
On the possible effective elasticity tensors of 2-dimensional and
  3-dimensional printed materials

abstract:
  The set $GU_f$ of possible effective elastic tensors of composites built from
two materials with elasticity tensors $\BC_1>0$ and $\BC_2=0$ comprising the
set $U=\{\BC_1,\BC_2\}$ and mixed in proportions $f$ and $1-f$ is partly
characterized. The material with tensor $\BC_2=0$ corresponds to a material
which is void. (For technical reasons $\BC_2$ is actually taken to be nonzero
and we take the limit $\BC_2\to 0$). Specifically, recalling that $GU_f$ is
completely characterized through minimums of sums of energies, involving a set
of applied strains, and complementary energies, involving a set of applied
stresses, we provide descriptions of microgeometries that in appropriate limits
achieve the minimums in many cases. In these cases the calculation of the
minimum is reduced to a finite dimensional minimization problem that can be
done numerically. Each microgeometry consists of a union of walls in
appropriate directions, where the material in the wall is an appropriate
$p$-mode material, that is easily compliant to $p\leq 5$ independent applied
strains, yet supports any stress in the orthogonal space. Thus the material can
easily slip in certain directions along the walls. The region outside the walls
contains "complementary Avellaneda material" which is a hierarchical laminate
which minimizes the sum of complementary energies.


title:
Optical Visualization of Radiative Recombination at Partial Dislocations
  in GaAs

abstract:
  Individual dislocations in an ultra-pure GaAs epilayer are investigated with
spatially and spectrally resolved photoluminescence imaging at 5~K. We find
that some dislocations act as strong non-radiative recombination centers, while
others are efficient radiative recombination centers. We characterize
luminescence bands in GaAs due to dislocations, stacking faults, and pairs of
stacking faults. These results indicate that low-temperature,
spatially-resolved photoluminescence imaging can be a powerful tool for
identifying luminescence bands of extended defects. This mapping could then be
used to identify extended defects in other GaAs samples solely based on
low-temperature photoluminescence spectra.


title: Entanglement, Holography and Causal Diamonds

abstract:
  We argue that the degrees of freedom in a d-dimensional CFT can be
re-organized in an insightful way by studying observables on the moduli space
of causal diamonds (or equivalently, the space of pairs of timelike separated
points). This 2d-dimensional space naturally captures some of the fundamental
nonlocality and causal structure inherent in the entanglement of CFT states.
For any primary CFT operator, we construct an observable on this space, which
is defined by smearing the associated one-point function over causal diamonds.
Known examples of such quantities are the entanglement entropy of vacuum
excitations and its higher spin generalizations. We show that in holographic
CFTs, these observables are given by suitably defined integrals of dual bulk
fields over the corresponding Ryu-Takayanagi minimal surfaces. Furthermore, we
explain connections to the operator product expansion and the first law of
entanglement entropy from this unifying point of view. We demonstrate that for
small perturbations of the vacuum, our observables obey linear two-derivative
equations of motion on the space of causal diamonds. In two dimensions, the
latter is given by a product of two copies of a two-dimensional de Sitter
space. For a class of universal states, we show that the entanglement entropy
and its spin-three generalization obey nonlinear equations of motion with local
interactions on this moduli space, which can be identified with Liouville and
Toda equations, respectively. This suggests the possibility of extending the
definition of our new observables beyond the linear level more generally and in
such a way that they give rise to new dynamically interacting theories on the
moduli space of causal diamonds. Various challenges one has to face in order to
implement this idea are discussed.


title: Sunward-propagating Alfv\'enic fluctuations observed in the heliosphere

abstract:
  The mixture/interaction of anti-sunward-propagating Alfv\'enic fluctuations
(AFs) and sunward-propagating Alfv\'enic fluctuations (SAFs) is believed to
result in the decrease of the Alfv\'enicity of solar wind fluctuations with
increasing heliocentric distance. However, SAFs are rarely observed at 1 au and
solar wind AFs are found to be generally outward. Using the measurements from
Voyager 2 and Wind, we perform a statistical survey of SAFs in the heliosphere
inside 6 au. We first report two SAF events observed by Voyager 2. One is in
the anti-sunward magnetic sector with a strong positive correlation between the
fluctuations of magnetic field and solar wind velocity. The other one is in the
sunward magnetic sector with a strong negative magnetic field-velocity
correlation. Statistically, the percentage of SAFs increases gradually with
heliocentric distance, from about 2.7% at 1.0 au to about 8.7% at 5.5 au. These
results provide new clues for understanding the generation mechanism of SAFs.


title: The symmetric signature

abstract:
  This is the author's Ph.D. thesis. We introduce two related invariants for
local (and standard graded) rings called differential and syzygy symmetric
signature. These are defined by looking at the maximal free splitting of the
module of K\"ahler differentials and of the the top-dimensional syzygy module
of the residue field respectively. We study and compute them for different
classes of rings: two-dimensional ADE singularities, two-dimensional cyclic
singularities, and cones over plane elliptic curves (for the differential
symmetric signature). The values obtained coincide with the F-signature of such
rings in positive characteristic. The thesis contains also a short survey on
the Auslander correspondence for quotient singularities.


title:
The Asymmetric Active Coupler: Stable Nonlinear Supermodes and Directed
  Transport

abstract:
  We consider the asymmetric active coupler (AAC) consisting of two coupled
dissimilar waveguides with gain and loss. We show that under generic
conditions, not restricted by parity-time symmetry, there exist finite-power,
constant-intensity nonlinear supermodes (NS), resulting from the balance
between gain, loss, nonlinearity, coupling and dissimilarity. The system is
shown to possess nonreciprocal dynamics enabling directed power transport and
optical isolation functionality.


title: Chirality in photonic systems

abstract:
  The optical modes of photonic structures are the so-called TE and TM modes
which bring intrinsic spin-orbit coupling and chirality to these systems. This,
combined with the unique flexibility of design of the photonic potential, and
the possibility to mix photon states with excitonic resonances, sensitive to
magnetic field and interactions, allows to achieve many phenomena, often
analogous to other solid state systems. In this contribution, we review in a
qualitative and comprehensive way several of these realizations, namely the
optical spin Hall effect, the creation of spin currents protected by a
non-trivial geometry, Berry curvature for photons, and the photonic/polaritonic
topological insulator.


title:
Equivalence of quantum field theories related by the theta-exact
  Seiberg-Witten map

abstract:
  The equivalence of the noncommutative U(N) quantum field theories related by
the theta-exact Seiberg-Witten maps is in this letter proven to all orders in
the perturbation theory with respect to the coupling constant. We show that
this duality holds for Super Yang-Mills theories with N=0,1,2,4 supersymmetry.
A direct check of this equivalence relation is performed by computing the
one-loop quantum corrections to the quadratic part of the effective action in
the noncommutative U(1) gauge theory with N=0,1,2,4 supersymmetry.


title: Resonant Thermoelectric Nanophotonics

abstract:
  Photodetectors are typically based on photocurrent generation from
electron-hole pairs in semiconductor structures and on bolometry for
wavelengths that are below bandgap absorption. In both cases, resonant
plasmonic and nanophotonic structures have been successfully used to enhance
performance. In this work, we demonstrate subwavelength thermoelectric
nanostructures designed for resonant spectrally selective absorption, which
creates large enough localized temperature gradients to generate easily
measureable thermoelectric voltages. We show that such structures are tunable
and are capable of highly wavelength specific detection, with an input power
responsivity of up to 119 V/W (referenced to incident illumination), and
response times of nearly 3 kHz, by combining resonant absorption and
thermoelectric junctions within a single structure, yielding a
bandgap-independent photodetection mechanism. We report results for both
resonant nanophotonic bismuth telluride-antimony telluride structures and
chromel-alumel structures as examples of a broad class of nanophotonic
thermoelectric structures useful for fast, low-cost and robust optoelectronic
applications such as non-bandgap-limited hyperspectral and broad-band
photodetectors.


title: Large Stark tuning of donor electron spin quantum bits in germanium

abstract:
  Donor electron spins in semiconductors make exceptional quantum bits because
of their long coherence times and compatibility with industrial fabrication
techniques. Despite many advances in donor-based qubit technology, it remains
difficult to selectively manipulate single donor electron spins. Here, we show
that by replacing the prevailing semiconductor host material (silicon) with
germanium, donor electron spin qubits can be electrically tuned by more than an
ensemble linewidth, making them compatible with gate addressable quantum
computing architectures. Using X-band pulsed electron spin resonance, we
measured the Stark effect for donor electron spins in germanium. We resolved
both spin-orbit and hyperfine Stark shifts and found that at 0.4 T, the
spin-orbit Stark shift dominates. The spin-orbit Stark shift is highly
anisotropic, depending on the electric field orientation relative to the
crystal axes and external magnetic field. When the Stark shift is maximized,
the spin-orbit Stark parameter is four orders of magnitude larger than in
silicon. At select orientations a hyperfine Stark effect was also resolved and
is an order of magnitude larger than in silicon. We report the Stark parameters
for $^{75}$As and $^{31}$P donor electrons and compare them to the available
theory. Our data reveal that $^{31}$P donors in germanium can be tuned by at
least four times the ensemble linewidth making germanium an appealing new host
material for spin qubits that offers major advantages over silicon.


title: Algebra and geometry of Hamilton's quaternions

abstract:
  Inspired by the relation between the algebra of complex numbers and plane
geometry, William Rowan Hamilton sought an algebra of triples for application
to three dimensional geometry. Unable to multiply and divide triples, he
invented a non-commutative division algebra of quadruples, in what he
considered his most significant work, generalizing the real and complex number
systems. We give a motivated introduction to quaternions and discuss how they
are related to Pauli matrices, rotations in three dimensions, the three sphere,
the group SU(2) and the celebrated Hopf fibrations.


title:
The Electronics and Data Acquisition System for the DarkSide-50 Veto
  Detectors

abstract:
  DarkSide-50 is a detector for dark matter candidates in the form of weakly
interacting massive particles (WIMPs). It utilizes a liquid argon time
projection chamber (LAr TPC) for the inner main detector. The TPC is surrounded
by a liquid scintillator veto (LSV) and a water Cherenkov veto detector (WCV).
The LSV and WCV, both instrumented with PMTs, act as the neutron and cosmogenic
muon veto detectors for DarkSide-50. This paper describes the electronics and
data acquisition system used for these two detectors.


title:
Continuous wave superconducting radio frequency electron linac for
  nuclear physics research

abstract:
  CEBAF, the Continuous Electron Beam Accelerator Facility, has been actively
serving the nuclear physics research community as a unique forefront
international resource since 1995. This CW electron linear accelerator (linac)
at the U.S. Department of Energy's Thomas Jefferson National Accelerator
Facility (Jefferson Lab) has continued to evolve as a precision tool for
discerning the structure and dynamics within nuclei. Superconducting RF (SRF)
technology has been the essential foundation for CEBAF, first as a 4 GeV
machine, then 6 GeV, and currently capable of 12 GeV. We review the
development, implementation, and performance of SRF systems for CEBAF from its
early beginnings to the commissioning of the 12 GeV era.


title:
Organic molecule fluorescence as an experimental test-bed for quantum
  jumps in thermodynamics

abstract:
  We demonstrate with an experiment how molecules are a natural test-bed for
probing fundamental quantum thermodynamics. Single-molecule spectroscopy has
undergone transformative change in the past decade with the advent of
techniques permitting individual molecules to be distinguished and probed. By
considering the time-resolved emission spectrum of organic molecules as arising
from quantum jumps between states, we demonstrate that the quantum Jarzynski
equality is satisfied in this set-up. This relates the heat dissipated into the
environment to the free energy difference between the initial and final state.
We demonstrate also how utilizing the quantum Jarzynski equality allows for the
detection of energy shifts within a molecule, beyond the relative shift.


title:
Towards carbon nanotube growth into superconducting microwave resonator
  geometries

abstract:
  The in-place growth of suspended carbon nanotubes facilitates the observation
of both unperturbed electronic transport spectra and high-Q vibrational modes.
For complex structures integrating, e.g., superconducting rf elements on-chip,
selection of a chemically and physically resistant material that survives the
chemical vapor deposition (CVD) process provides a challenge. We demonstrate
the implementation of molybdenum-rhenium coplanar waveguide resonators that
exhibit clear resonant behaviour at cryogenic temperatures even after having
been exposed to nanotube growth conditions. The properties of the MoRe devices
before and after CVD are compared to a reference niobium device.


title: A plectic Taniyama group

abstract:
  We revisit Langlands' construction of the Taniyama group to define a plectic
Taniyama group for any totally real field F. The construction is functorial in
F and recovers Langlands' original Taniyama group when F = Q. We relate our
construction to Nekovar's 'hidden symmetries' in classical CM theory,
generalising the relationship between the Taniyama group and Tate's
half-transfer maps.


title: Revised Elements and Blazhko Effect of the RR Lyrae Star AR Herculis

abstract:
  AR Herculis is an RR Lyrae star of type RRab whose spectral type ranges from
A7 to F3. Its visual brightness varies between 10.59 mag and 11.63 mag (V). By
analysis of 34,000 measurements from the AAVSO International Database and
additional data from the BAV, 116 times of maximum between 2003 and 2015 were
derived. For the time span 2009 to 2015, a new period value of P =
0.46999746(145) days was derived from the (O-C) analysis. Furthermore, the
derived maximum timings indicate a strong Blazhko effect with a Blazhko period
of PB = 32.062(13) days. The evolution of the observed maximum brightness Vmax,
which decreased from 2009 to 2015 by 22 mmag/year, is also indicative of a
Blazhko effect with PB = 29.528(17) d. The present work investigates the
processes in the frequently used (O-C) vs. Vmax diagram by running several
simulations based on assumed and observational data.


title: Coherence and information in a fiber interferometer

abstract:
  We present an experiment based on a fibered Mach-Zehnder interferometer. The
aim is to familiarize students with fibered optics and interferometry, and to
improve their understanding of optical amplification. The laboratory project
has two parts: in a first part, the students modulate the optical path of the
interferometer to study the spectra of light sources via Fourier Transform
Spectroscopy. In a second part, an optical amplifier is placed in one or both
arms of the interferometer. The set-up uses monomode, polarization-maintaining
fibers that propagate light of 1.5 $\mu$m wavelength. In this article, we
describe the set-up and the analysis of the measurements, and we present
results from student reports. All components are part of standard optical
catalogues. Even though the experiment is based on fibered optics, it is robust
to manipulation (it is however relatively expensive $\sim \pounds 15\,000$): We
describe our efforts to protect the components from damage.
  This experiment is now offered as a 2-week project for third-year Physics
students. The experiment may likewise be of value in early graduate level
laboratory courses.


title: Simulating Dicke like superradiance with classical light sources

abstract:
  In this paper we investigate the close relationship between Dicke
superradiance, originally predicted for an ensemble of two-level atoms in
entangled states, and the Hanbury Brown and Twiss effect, initially established
in astronomy to determine the dimensions of classical light sources like stars.
By studying the state evolution of the fields produced by classical sources --
defined by a positive Glauber-Sudarshan P function -- when recording intensity
correlations of higher order in a generalized Hanbury Brown and Twiss setup we
find that the angular distribution of the last detected photon, apart from an
offset, is identical to the superradiant emission pattern generated by an
ensemble of two-level atoms in entangled symmetric Dicke states. We show that
the phenomenon derives from projective measurements induced by the measurement
of photons in the far field of the sources and the permutative superposition of
quantum paths identical to those leading to superradiance in the case of single
photon emitters. We thus point out an important similarity between classical
sources and quantum emitters upon detection of photons if the particular photon
source remains unknown. We finally present a compact result for the
characteristic functional which generates intensity correlations of arbitrary
order for any kind of light sources.


title: Gauging Geometry: A Didactic Lecture

abstract:
  Local inertial frame invariance is taken as the fundamental principle of
physical geometry, where a local inertial frame is represented by a verbein.
Invariance of the vierbein with respect to local Lorentz transformations then
expresses local inertial frame invariance. The dynamics of physical geometry
develops as a gauge theory of the verbein that is closely analogous to the
Yang-Mills field provided the verbein connection and curvature correspond to
the geometric potential and field respectively. The resulting theory is shown
to be equivalent to Einstein's tensor form of relativistic gravitation.


title: Model-free portfolio theory and its functional master formula

abstract:
  We use pathwise It\^o calculus to prove two strictly pathwise versions of the
master formula in Fernholz' stochastic portfolio theory. Our first version is
set within the framework of F\"ollmer's pathwise It\^o calculus and works for
portfolios generated from functions that may depend on the current states of
the market portfolio and an additional path of finite variation. The second
version is formulated within the functional pathwise It\^o calculus of Dupire
(2009) and Cont \& Fourni\'e (2010) and allows for portfolio-generating
functionals that may depend additionally on the entire path of the market
portfolio. Our results are illustrated by several examples and shown to work on
empirical market data.


title:
A Lower Bound Analysis of Population-based Evolutionary Algorithms for
  Pseudo-Boolean Functions

abstract:
  Evolutionary algorithms (EAs) are population-based general-purpose
optimization algorithms, and have been successfully applied in various
real-world optimization tasks. However, previous theoretical studies often
employ EAs with only a parent or offspring population and focus on specific
problems. Furthermore, they often only show upper bounds on the running time,
while lower bounds are also necessary to get a complete understanding of an
algorithm. In this paper, we analyze the running time of the
($\mu$+$\lambda$)-EA (a general population-based EA with mutation only) on the
class of pseudo-Boolean functions with a unique global optimum. By applying the
recently proposed switch analysis approach, we prove the lower bound $\Omega(n
\ln n+ \mu + \lambda n\ln\ln n/ \ln n)$ for the first time. Particularly on the
two widely-studied problems, OneMax and LeadingOnes, the derived lower bound
discloses that the ($\mu$+$\lambda$)-EA will be strictly slower than the
(1+1)-EA when the population size $\mu$ or $\lambda$ is above a moderate order.
Our results imply that the increase of population size, while usually desired
in practice, bears the risk of increasing the lower bound of the running time
and thus should be carefully considered.


title: The zero dynamics of feedback linearisation and Ehresmann connections

abstract:
  The notion of zero dynamics is a cornerstone of many solutions to important
control problems such as feedback linearisation and disturbance decoupling. For
a SISO affine control system with relative degree strictly less than the order
of the system, it is known that there exists a state transformation and a
feedback transformation such that the system can be transformed to a linear
system. Making use of the fibre bundle structure induced by the state
transformation we show that it is possible to define a connection on the state
manifold such that the zero dynamics can be defined as a vertical vector field.
In this formalism the zero dynamics can be understood as motions along the
fibres of a fibre bundle.


title: Descent in algebraic $K$-theory and a conjecture of Ausoni-Rognes

abstract:
  Let $A \to B$ be a $G$-Galois extension of rings, or more generally of
$\mathbb{E}_\infty$-ring spectra in the sense of Rognes. A basic question in
algebraic $K$-theory asks how close the map $K(A) \to K(B)^{hG}$ is to being an
equivalence, i.e., how close algebraic $K$-theory is to satisfying Galois
descent. An elementary argument with the transfer shows that this equivalence
is true rationally in most cases of interest. Motivated by the classical
descent theorem of Thomason, one also expects such a result after periodic
localization.
  We formulate and prove a general result which enables one to promote rational
descent statements as above into descent statements after periodic
localization. This reduces the localized descent problem to establishing an
elementary condition on $K_0(-)\otimes \mathbb{Q}$. As applications, we prove
various descent results in the periodic localized $K$-theory, $TC$, $THH$, etc.
of structured ring spectra, and verify several cases of a conjecture of Ausoni
and Rognes.


title: Community Structure in Industrial SAT Instances

abstract:
  Modern SAT solvers have experienced a remarkable progress on solving
industrial instances. Most of the techniques have been developed after an
intensive experimental process. It is believed that these techniques exploit
the underlying structure of industrial instances. However, there are few works
trying to exactly characterize the main features of this structure.
  The research community on complex networks has developed techniques of
analysis and algorithms to study real-world graphs that can be used by the SAT
community. Recently, there have been some attempts to analyze the structure of
industrial SAT instances in terms of complex networks, with the aim of
explaining the success of SAT solving techniques, and possibly improving them.
  In this paper, inspired by the results on complex networks, we study the
community structure, or modularity, of industrial SAT instances. In a graph
with clear community structure, or high modularity, we can find a partition of
its nodes into communities such that most edges connect variables of the same
community. In our analysis, we represent SAT instances as graphs, and we show
that most application benchmarks are characterized by a high modularity. On the
contrary, random SAT instances are closer to the classical Erd\"os-R\'enyi
random graph model, where no structure can be observed. We also analyze how
this structure evolves by the effects of the execution of a CDCL SAT solver. In
particular, we use the community structure to detect that new clauses learned
by the solver during the search contribute to destroy the original structure of
the formula. This is, learned clauses tend to contain variables of distinct
communities.


title: Time-Inconsistent Recursive Stochastic Optimal Control Problems

abstract:
  In this paper, we study a time-inconsistent stochastic optimal control
problem with a recursive cost functional by a multi-person hierarchical
differential game approach. An equilibrium strategy of this problem is
constructed and a corresponding equilibrium Hamilton-Jacobi-Bellman (HJB, for
short) equation is established to characterize the associated equilibrium value
function. Moreover, a well-posedness result of the equilibrium HJB equation is
established under certain conditions.


title: Thin position for knots, links, and graphs in 3-manifolds

abstract:
  We define a new notion of thin position for a graph in a 3-manifold which
combines the ideas of thin position for manifolds first originated by
Scharlemann and Thompson with the idea of thin position for knots first
originated by Gabai. This thin position has the property that connect summing
annuli and pairs-of-pants show up as thin levels. In a forthcoming paper, this
new thin position allows us to define two new families of invariants of knots,
links, and graphs in 3-manifolds. The invariants in one family are similar to
bridge number and the invariants in the other family are similar to Gabai's
width for knots in the 3-sphere. The invariants in both families detect the
unknot and are additive under connected sum and trivalent vertex sum.