title:
Funneled Bayesian Optimization for Design, Tuning and Control of
  Autonomous Systems

abstract:
  Bayesian optimization has become a fundamental global optimization algorithm
in many problems where sample efficiency is of paramount importance. Recently,
there has been proposed a large number of new applications in fields such as
robotics, machine learning, experimental design, simulation, etc. In this
paper, we focus on several problems that appear in robotics and autonomous
systems: algorithm tuning, automatic control and intelligent design. All those
problems can be mapped to global optimization problems. However, they become
hard optimization problems. Bayesian optimization internally uses a
probabilistic surrogate model (e.g.: Gaussian process) to learn from the
process and reduce the number of samples required. In order to generalize to
unknown functions in a black-box fashion, the common assumption is that the
underlying function can be modeled with a stationary process. Nonstationary
Gaussian process regression cannot generalize easily and it typically requires
prior knowledge of the function. Some works have designed techniques to
generalize Bayesian optimization to nonstationary functions in an indirect way,
but using techniques originally designed for regression, where the objective is
to improve the quality of the surrogate model everywhere. Instead optimization
should focus on improving the surrogate model near the optimum. In this paper,
we present a novel kernel function specially designed for Bayesian
optimization, that allows nonstationary behavior of the surrogate model in an
adaptive local region. In our experiments, we found that this new kernel
results in an improved local search (exploitation), without penalizing the
global search (exploration). We provide results in well-known benchmarks and
real applications. The new method outperforms the state of the art in Bayesian
optimization both in stationary and nonstationary problems.


title: The dynamical Mordell-Lang conjecture in positive characteristic

abstract:
  Let K be an algebraically closed field of prime characteristic p, let N be a
positive integer, let f be a self-map on the algebraic torus T=G_m^N defined
over K, let V be a curve in T defined over K, and let x be a K-point of T. We
show that the set S consisting of all positive integers n for which f^n(x) is
contained in V is a union of finitely many arithmetic progressions, along with
a finite set and with finitely many p-arithmetic sequences, which are sets of
the form {b + ap^{kn}: n is a positive integer} where a and b are given
rational numbers and k is a positive integer. We also prove that our result is
sharp in the sense that S may be infinite without containing an arithmetic
progression. Our result addresses a positive characteristic version of the
dynamical Mordell-Lang conjecture and it is the first known instance when a
structure theorem is proven for the set S which includes p-arithmetic
sequences.


title: Covert Communications on Renewal Packet Channels

abstract:
  Security and privacy are major concerns in modern communication networks. In
recent years, the information theory of covert communications, where the very
presence of the communication is undetectable to a watchful and determined
adversary, has been of great interest. This emerging body of work has focused
on additive white Gaussian noise (AWGN), discrete memoryless channels (DMCs),
and optical channels. In contrast, our recent work introduced the
information-theoretic limits for covert communications over packet channels
whose packet timings are governed by a Poisson point process. However, actual
network packet arrival times do not generally conform to the Poisson process
assumption, and thus here we consider the extension of our work to timing
channels characterized by more general renewal processes of rate $\lambda$. We
consider two scenarios. In the first scenario, the source of the packets on the
channel cannot be authenticated by Willie, and therefore Alice can insert
packets into the channel. We show that if the total number of transmitted
packets by Jack is $N$, Alice can covertly insert
$\mathcal{O}\left(\sqrt{N}\right)$ packets and, if she transmits more, she will
be detected by Willie. In the second scenario, packets are authenticated by
Willie but we assume that Alice and Bob share a secret key; hence, Alice alters
the timings of the packets according to a pre-shared codebook with Bob to send
information to him over a $G/M/1$ queue with service rate $\mu>\lambda$. We
show that Alice can covertly and reliably transmit $\mathcal{O}(N)$ bits to Bob
when the total number of packets sent from Jack to Steve is $N$.


title:
Sentiment Analysis on Bangla and Romanized Bangla Text (BRBT) using Deep
  Recurrent models

abstract:
  Sentiment Analysis (SA) is an action research area in the digital age. With
rapid and constant growth of online social media sites and services, and the
increasing amount of textual data such as - statuses, comments, reviews etc.
available in them, application of automatic SA is on the rise. However, most of
the research works on SA in natural language processing (NLP) are based on
English language. Despite being the sixth most widely spoken language in the
world, Bangla still does not have a large and standard dataset. Because of
this, recent research works in Bangla have failed to produce results that can
be both comparable to works done by others and reusable as stepping stones for
future researchers to progress in this field. Therefore, we first tried to
provide a textual dataset - that includes not just Bangla, but Romanized Bangla
texts as well, is substantial, post-processed and multiple validated, ready to
be used in SA experiments. We tested this dataset in Deep Recurrent model,
specifically, Long Short Term Memory (LSTM), using two types of loss functions
- binary crossentropy and categorical crossentropy, and also did some
experimental pre-training by using data from one validation to pre-train the
other and vice versa. Lastly, we documented the results along with some
analysis on them, which were promising.


title: Compact metrizable structures and classification problems

abstract:
  We introduce and study the framework of compact metric structures and their
associated notions of isomorphisms such as homeomorphic and bi-Lipschitz
isomorphism. This is subsequently applied to model various classification
problems in analysis such as isomorphism of C*-algebras and affine
homeomorphism of Choquet simplices, where among other things we provide a
simple proof of the completeness of the isomorphism relation of separable,
simple, nuclear C*-algebras recently established by M. Sabok.


title: White Dwarf Mass Distribution

abstract:
  We present the mass distribution for all S/N > 15 pure DA white dwarfs
detected in the Sloan Digital Sky Survey up to Data Release 12, fitted with
Koester models for ML2/alpha=0.8, and with Teff > 10 000 K, and for DBs with
S/N >10, fitted with ML2/alpha=1.25, for Teff > 16 000 K. These mass
distributions are for log g > 6.5 stars, i.e., excluding the Extremely Low Mass
white dwarfs. We also present the mass distributions corrected by volume with
the 1/Vmax approach, for stars brighter than g=19. Both distributions have a
maximum at M=0.624 Msun but very distinct shapes. From the estimated
z-distances, we deduce a disk scale height of 300 pc. We also present 10
probable halo white dwarfs, from their galactic U, V, W velocities.


title: Degree Ramsey numbers for even cycles

abstract:
  Let $H\xrightarrow{s} G$ denote that any $s$-coloring of $E(H)$ contains a
monochromatic $G$. The degree Ramsey number of a graph $G$, denoted by
$R_\Delta(G, s)$, is $\min \{\Delta(H): H \xrightarrow{s} G \}$. We consider
degree Ramsey numbers where $G$ is a fixed even cycle. Kinnersley, Milans, and
West showed that $R_\Delta(C_{2k},s) \geq 2s$, and Kang and Perarnau showed
that $R_\Delta(C_4, s) = \Theta(s^2)$. Our main result is that $R_\Delta(C_6,
s) = \Theta(s^{3/2})$ and $R_\Delta(C_{10}, s) = \Theta(s^{5/4})$.
Additionally, we substantially improve the lower bound for $R_\Delta(C_{2k},
s)$ for general $k$.


title: The Complexity of Knapsack in Graph Groups

abstract:
  Myasnikov et al. have introduced the knapsack problem for arbitrary finitely
generated groups. In previous work, the authors proved that for each graph
group, the knapsack problem can be solved in $\mathsf{NP}$. Here, we determine
the exact complexity of the problem for every graph group. While the problem is
$\mathsf{TC}^0$-complete for complete graphs, it is $\mathsf{LogCFL}$-complete
for each (non-complete) transitive forest. For every remaining graph, the
problem is $\mathsf{NP}$-complete.


title:
Estimates for the first eigenvalue of Jacobi operator on hypersurfaces
  with constant mean curvature in spheres

abstract:
  In this paper, we study the first eigenvalue of Jacobi operator on an
$n$-dimensional non-totally umbilical compact hypersurface with constant mean
curvature $H$ in the unit sphere $S^{n+1}(1)$. We give an optimal upper bound
for the first eigenvalue of Jacobi operator, which only depends on the mean
curvature $H$ and the dimension $n$.


title:
Amino acid preference against beta sheet through allowing backbone
  hydration enabled by the presence of cation

abstract:
  It is known that steric blocking by peptide sidechains of hydrogen bonding,
HB, between water and peptide groups, PGs, in beta sheets accords with an amino
acid intrinsic beta sheet preference. The present observations with Quantum
Molecular Dynamics, QMD, simulation with quantum mechanical treatment of every
water molecule solvating a beta sheet that would be transient in nature suggest
that this steric blocking is not applicable in a hydrophobic region unless a
cation is present, so that the amino acid beta sheet preference due to this
steric blocking is only effective in the presence of a cation. We observed
backbone hydration in a polyalanine and to a lesser extent polyvaline alpha
helix without a cation being present, but a cation could increase the strength
of these HBs.
  Parallel beta sheets have a greater tendency than antiparallel beta sheets of
equivalent small size to retain regular structure in solvated QMD, and a 4
strand 4 inter-PG HB chain parallel beta sheet was used. Stability was
reinforced by one surface being polyvaline, which buttressed the opposite
surface which was used for experimentation. A single Ca2+ ion was used for
investigation of individual binding events rather than bulk properties. No
direct binding between Ca2+ and the PG oxygen was observed in these
simulations, but perhaps it occurs at longer time scales as the transient beta
sheet unfolds.
  When linear scaling QMD methods that are accurate for peptide resonance,
Resonance-Assisted Hydrogen Bonding and the properties of water become
available, more extensive experiments having multiple ions of multiple types
could be performed at acceptable computational cost. It important that such
investigations be performed on protein secondary structures rather than model
amides so that sidechain limitation of backbone hydration and hence intrinsic
amino acid propensity is captured.


title: Thermodynamics and phase transition in rotational Kiselev black hole

abstract:
  In this work, we investigate the thermodynamic properties of rotational
Kiselev black holes (KBH). Specifically, we use the first-order approximation
of the event horizon (EH) to calculate thermodynamic properties for general
equations of state $\omega$. These thermodynamic properties include areas,
entropies, horizon radii, surface gravities, surface temperatures, Komar
energies and irreducible masses at the Cauchy horizon (CH) and EH. We study the
products of these thermodynamic quantities, we find that these products are
determined by the equation of state $\omega$ and strength parameter $\alpha$.
In the case of the quintessence matter ($\omega=-2/3$), radiation
($\omega=1/3$) and dust ($\omega=0$), we discuss their properties in detail. We
also generalize the Smarr mass formula and Christodoulou-Ruffini mass formula
to rotational KBH. Finally we study the phase transition and thermodynamic
geometry for rotational KBH with radiation ($\omega=1/3$). Through analysis, we
find that this phase transition is a second order phase transition.
Furthermore, we also obtain the scalar curvature in the thermodynamic geometry
framework, indicating that the radiation matter may change the phase transition
condition and properties for Kerr black hole.


title: Stochastic p-bits for Invertible Logic

abstract:
  Conventional logic and memory devices are built out of deterministic units
such as transistors, or magnets with energy barriers in excess of 40-60 kT. We
show that stochastic units, p-bits, can be interconnected to create robust
correlations that implement Boolean functions with impressive accuracy,
comparable to standard circuits. Also they are invertible, a unique property
that is absent in digital circuits. When operated in the direct mode, the input
is clamped, and the network provides the correct output. In the inverted mode,
the output is clamped, and the network fluctuates among possible inputs
consistent with that output. We present an implementation of an invertible gate
to bring out the key role of a three-terminal building block to enable the
construction of correlated p-bit networks. The results for this implementation
agree well with those from a universal model, showing that p-bits need not be
magnet-based: any three-terminal tunable random bit generator should be
suitable. We present an algorithm for designing a Boltzmann machine (BM) with
symmetric connections that implements a given truth table. We then show how BM
Full Adders can be interconnected in a partially directed manner to implement
large operations such as 32-bit addition. Hundreds of p-bits get precisely
correlated such that the correct answer out of 2^33 possibilities can be
extracted by looking at the mode of a number of time samples. With perfect
directivity a small number of samples is enough, while for less directed
connections more samples are needed, but even in the former case invertibility
is largely preserved. This combination of accuracy and invertibility is enabled
by the hybrid design that uses bidirectional units to construct circuits with
partially directed connections. We establish this result with examples
including a 4-bit multiplier which in inverted mode functions as a factorizer.


title:
Improving Accuracy and Scalability of the PC Algorithm by Maximizing
  P-value

abstract:
  A number of attempts have been made to improve accuracy and/or scalability of
the PC (Peter and Clark) algorithm, some well known (Buhlmann, et al., 2010;
Kalisch and Buhlmann, 2007; 2008; Zhang, 2012, to give some examples). We add
here one more tool to the toolbox: the simple observation that if one is forced
to choose between a variety of possible conditioning sets for a pair of
variables, one should choose the one with the highest p-value. One can use the
CPC (Conservative PC, Ramsey et al., 2012) algorithm as a guide to possible
sepsets for a pair of variables. However, whereas CPC uses a voting rule to
classify colliders versus noncolliders, our proposed algorithm, PC-Max, picks
the conditioning set with the highest p-value, so that there are no
ambiguities. We combine this with two other optimizations: (a) avoiding
bidirected edges in the orientation of colliders, and (b) parallelization. For
(b) we borrow ideas from the PC-Stable algorithm (Colombo and Maathuis, 2014).
The result is an algorithm that scales quite well both in terms of accuracy and
time, with no risk of bidirected edges.


title: The quantum beating and its numerical simulation

abstract:
  We examine the suppression of quantum beating in a one dimensional non-
linear double well potential, made up of two focusing nonlinear point
interactions. The investigation of the Schr\"odinger dynamics is reduced to the
study of a system of coupled nonlinear Volterra integral equations. For various
values of the geometric and dynamical parameters of the model we give
analytical and numerical results on the way states, which are initially
confined in one well, evolve. We show that already for a nonlinearity exponent
well below the critical value there is complete suppression of the typical
beating behavior characterizing the linear quantum case.


title:
On localization and the spectrum of multi-frequency quasi-periodic
  operators

abstract:
  We study multi-frequency quasi-periodic Schr\"odinger operators on
$\mathbb{Z}$ in the regime of positive Lyapunov exponent and for general
analytic potentials. Combining Bourgain's semi-algebraic elimination of
multiple resonances with the method of elimination of double resonances via
resultants, we establish exponential finite-volume localization as well as the
separation between the eigenvalues. In a follow-up paper we develop the method
further to show that for potentials given by large generic trigonometric
polynomials the spectrum consists of a single interval, as conjectured by
Chulaevski and Sinai.


title: Covert Communications on Poisson Packet Channels

abstract:
  Consider a channel where authorized transmitter Jack sends packets to
authorized receiver Steve according to a Poisson process with rate $\lambda$
packets per second for a time period $T$. Suppose that covert transmitter Alice
wishes to communicate information to covert receiver Bob on the same channel
without being detected by a watchful adversary Willie. We consider two
scenarios. In the first scenario, we assume that warden Willie cannot look at
packet contents but rather can only observe packet timings, and Alice must send
information by inserting her own packets into the channel. We show that the
number of packets that Alice can covertly transmit to Bob is on the order of
the square root of the number of packets that Jack transmits to Steve;
conversely, if Alice transmits more than that, she will be detected by Willie
with high probability. In the second scenario, we assume that Willie can look
at packet contents but that Alice can communicate across an $M/M/1$ queue to
Bob by altering the timings of the packets going from Jack to Steve. First,
Alice builds a codebook, with each codeword consisting of a sequence of packet
timings to be employed for conveying the information associated with that
codeword. However, to successfully employ this codebook, Alice must always have
a packet to send at the appropriate time. Hence, leveraging our result from the
first scenario, we propose a construction where Alice covertly slows down the
packet stream so as to buffer packets to use during a succeeding codeword
transmission phase. Using this approach, Alice can covertly and reliably
transmit $\mathcal{O}(\lambda T)$ covert bits to Bob in time period $T$ over an
$M/M/1$ queue with service rate $\mu > \lambda$.


title: Near-Infrared Coloring via a Contrast-Preserving Mapping Model

abstract:
  Near-infrared gray images captured together with corresponding visible color
images have recently proven useful for image restoration and classification.
This paper introduces a new coloring method to add colors to near-infrared gray
images based on a contrast-preserving mapping model. A naive coloring method
directly adds the colors from the visible color image to the near-infrared gray
image; however, this method results in an unrealistic image because of the
discrepancies in brightness and image structure between the captured
near-infrared gray image and the visible color image. To solve the discrepancy
problem, first we present a new contrast-preserving mapping model to create a
new near-infrared gray image with a similar appearance in the luminance plane
to the visible color image, while preserving the contrast and details of the
captured near-infrared gray image. Then based on the proposed
contrast-preserving mapping model, we develop a method to derive realistic
colors that can be added to the newly created near-infrared gray image.
Experimental results show that the proposed method can not only preserve the
local contrasts and details of the captured near-infrared gray image, but
transfers the realistic colors from the visible color image to the newly
created near-infrared gray image. Experimental results also show that the
proposed approach can be applied to near-infrared denoising.


title:
Hindrances to precise recovery of cellular forces in fibrous biopolymer
  networks

abstract:
  How cells move through the three-dimensional extracellular matrix (ECM) is of
increasing interest in attempts to understand important biological processes
such as cancer metastasis. Just as in motion on flat surfaces, it is expected
that experimental measurements of cell-generated forces will provide valuable
information for uncovering the mechanisms of cell migration. However, the
recovery of forces in fibrous biopolymer networks may suffer from large errors.
Here, within the framework of lattice-based models, we explore possible issues
in force recovery by solving the inverse problem: how can one determine the
forces cells exert to their surroundings from the deformation of the ECM? Our
results indicate that irregular cell traction patterns, the uncertainty of
local fiber stiffness, the non-affine nature of ECM deformations and inadequate
knowledge of network topology will all prevent the precise force determination.
At the end, we discuss possible ways of overcoming these difficulties.


title:
Covert Single-hop Communication in a Wireless Network with Distributed
  Artificial Noise Generation

abstract:
  Covert communication, also known as low probability of detection (LPD)
communication, prevents the adversary from knowing that a communication is
taking place. Recent work has demonstrated that, in a three-party scenario with
a transmitter (Alice), intended recipient (Bob), and adversary (Warden Willie),
the maximum number of bits that can be transmitted reliably from Alice to Bob
without detection by Willie, when additive white Gaussian noise (AWGN) channels
exist between all parties, is on the order of the square root of the number of
channel uses. In this paper, we begin consideration of network scenarios by
studying the case where there are additional "friendly" nodes present in the
environment that can produce artificial noise to aid in hiding the
communication. We establish achievability results by considering constructions
where the system node closest to the warden produces artificial noise and
demonstrate a significant improvement in the throughput achieved covertly,
without requiring close coordination between Alice and the noise-generating
node. Conversely, under mild restrictions on the communication strategy, we
demonstrate no higher covert throughput is possible. Extensions to the
consideration of the achievable covert throughput when multiple wardens
randomly located in the environment collaborate to attempt detection of the
transmitter are also considered.


title:
Pressurizing Field-Effect Transistors of Few-Layer MoS2 in a Diamond
  Anvil Cell

abstract:
  Hydrostatic pressure applied using diamond anvil cells (DAC) has been widely
explored to modulate physical properties of materials by tuning their lattice
degree of freedom. Independently, electrical field is able to tune the
electronic degree of freedom of functional materials via, for example, the
field-effect transistor (FET) configuration. Combining these two orthogonal
approaches would allow discovery of new physical properties and phases going
beyond the known phase space. Such experiments are, however, technically
challenging and have not been demonstrated. Herein, we report a feasible
strategy to prepare and measure FETs in a DAC by lithographically patterning
the nanodevices onto the diamond culet. Multiple-terminal FETs were fabricated
in the DAC using few-layer MoS2 and BN as the channel semiconductor and
dielectric layer, respectively. It is found that the mobility, conductance,
carrier concentration, and contact conductance of MoS2 can all be significantly
enhanced with pressure. We expect that the approach could enable unprecedented
ways to explore new phases and properties of materials under coupled
mechano-electrostatic modulation.


title:
Rain Removal via Shrinkage-Based Sparse Coding and Learned Rain
  Dictionary

abstract:
  This paper introduces a new rain removal model based on the shrinkage of the
sparse codes for a single image. Recently, dictionary learning and sparse
coding have been widely used for image restoration problems. These methods can
also be applied to the rain removal by learning two types of rain and non-rain
dictionaries and forcing the sparse codes of the rain dictionary to be zero
vectors. However, this approach can generate unwanted edge artifacts and detail
loss in the non-rain regions. Based on this observation, a new approach for
shrinking the sparse codes is presented in this paper. To effectively shrink
the sparse codes in the rain and non-rain regions, an error map between the
input rain image and the reconstructed rain image is generated by using the
learned rain dictionary. Based on this error map, both the sparse codes of rain
and non-rain dictionaries are used jointly to represent the image structures of
objects and avoid the edge artifacts in the non-rain regions. In the rain
regions, the correlation matrix between the rain and non-rain dictionaries is
calculated. Then, the sparse codes corresponding to the highly correlated
signal-atoms in the rain and non-rain dictionaries are shrunk jointly to
improve the removal of the rain structures. The experimental results show that
the proposed shrinkage-based sparse coding can preserve image structures and
avoid the edge artifacts in the non-rain regions, and it can remove the rain
structures in the rain regions. Also, visual quality evaluation confirms that
the proposed method outperforms the conventional texture and rain removal
methods.


title:
Scheme-Independent Series Expansions at an Infrared Zero of the Beta
  Function in Asymptotically Free Gauge Theories

abstract:
  We consider an asymptotically free vectorial gauge theory, with gauge group
$G$ and $N_f$ fermions in a representation $R$ of $G$, having an infrared (IR)
zero in the beta function at $\alpha_{IR}$. We present general formulas for
scheme-independent series expansions of quantities, evaluated at $\alpha_{IR}$,
as powers of an $N_f$-dependent expansion parameter, $\Delta_f$. First, we
apply these to calculate the derivative $d\beta/d\alpha$ evaluated at
$\alpha_{IR}$, denoted $\beta'_{IR}$, which is equivalent to the anomalous
dimension of the ${\rm Tr}(F_{\mu\nu}F^{\mu\nu})$ operator, to order
$\Delta_f^4$ for general $G$ and $R$, and to order $\Delta_f^5$ for $G={\rm
SU}(3)$ and fermions in the fundamental representation. Second, we calculate
the scheme-independent expansions of the anomalous dimension of the
flavor-nonsinglet and flavor-singlet bilinear fermion antisymmetric Dirac
tensor operators up to order $\Delta_f^3$. The results are compared with
rigorous upper bounds on anomalous dimensions of operators in conformally
invariant theories. Our other results include an analysis of the limit $N_c \to
\infty$, $N_f \to \infty$ with $N_f/N_c$ fixed, calculation and analysis of
Pad\'e approximants, and comparison with conventional higher-loop calculations
of $\beta'_{IR}$ and anomalous dimensions as power series in $\alpha$.


title: Learning to Translate in Real-time with Neural Machine Translation

abstract:
  Translating in real-time, a.k.a. simultaneous translation, outputs
translation words before the input sentence ends, which is a challenging
problem for conventional machine translation methods. We propose a neural
machine translation (NMT) framework for simultaneous translation in which an
agent learns to make decisions on when to translate from the interaction with a
pre-trained NMT environment. To trade off quality and delay, we extensively
explore various targets for delay and design a method for beam-search
applicable in the simultaneous MT setting. Experiments against state-of-the-art
baselines on two language pairs demonstrate the efficacy of the proposed
framework both quantitatively and qualitatively.


title:
How the First Stars Regulated Star Formation. II. Enrichment by Nearby
  Supernovae

abstract:
  Metals from Population III (Pop III) supernovae led to the formation of less
massive Pop II stars in the early universe, altering the course of evolution of
primeval galaxies and cosmological reionization. There are a variety of
scenarios in which heavy elements from the first supernovae were taken up into
second-generation stars, but cosmological simulations only model them on the
largest scales. We present small-scale, high-resolution simulations of the
chemical enrichment of a primordial halo by a nearby supernova after partial
evaporation by the progenitor star. We find that ejecta from the explosion
crash into and mix violently with ablative flows driven off the halo by the
star, creating dense, enriched clumps capable of collapsing into Pop II stars.
Metals may mix less efficiently with the partially exposed core of the halo, so
it might form either Pop III or Pop II stars. Both Pop II and III stars may
thus form after the collision if the ejecta do not strip all the gas from the
halo. The partial evaporation of the halo prior to the explosion is crucial to
its later enrichment by the supernova.


title: Anomalous Thermal Hall Effect in a Disordered Weyl Ferromagnet

abstract:
  We investigate the electric and thermal transport properties in a disordered
Weyl ferromagnet on an equal footing by using the Keldysh formalism in curved
spacetime. In particular, we calculate the anomalous thermal Hall conductivity,
which consists of the Kubo formula and the heat magnetization, without relying
on the Wiedemann-Franz law. We take nonmagnetic impurities into account within
the self-consistent $T$-matrix approximation and reproduce the Wiedemann-Franz
law for the extrinsic Fermi-surface and intrinsic Fermi-sea terms,
respectively. This is the first step towards a unified theory of the anomalous
Hall effect at finite temperature, where we should take into account both
disorder and interactions.


title: Polymer Entanglement Dynamics: Role of Attractive Interactions

abstract:
  The coupled dynamics of entangled polymers which span a broad time and length
scales govern the unique viscoelastic properties of polymers. To follow chain
mobility by numerical simulations from the intermediate Rouse and reptation
regimes to the late time diffusive regime, highly coarse grained models with
purely repulsive interactions between monomers are widely used since they are
computationally the most efficient. Here using large scale molecular dynamics
simulations the effect of including the attractive interaction between monomers
on the dynamics of entangled polymers melts is explored for the first time over
wide temperature range. Attractive interactions has little effect on the local
packing for all temperatures T and on the chain mobility for T higher than
about twice the glass transition Tg. These results, across a broad range of
molecular weight, show that to study the dynamics of entangled polymers melts
the interactions can be treated as pure repulsive, confirming a posteriori the
validity of previous studies and opening the way to new large scale numerical
simulations.


title: Thermal backflow in CFTs

abstract:
  We study the thermal transport properties of general conformal field theories
(CFTs) on curved spacetimes in the leading order viscous hydrodynamic limit. At
the level of linear response, we show that the thermal transport is governed by
a system of forced linearised Navier-Stokes equations on a curved space. Our
setup includes CFTs in flat spacetime that have been deformed by spatially
dependent and periodic local temperature variations or strains that have been
applied to the CFT, and hence is relevant to CFTs arising in condensed matter
systems at zero charge density. We provide specific examples of deformations
which lead to thermal backflow driven by a DC source: that is, the thermal
currents locally flow in the opposite direction to the applied DC thermal
source. We also consider thermal transport for relativistic quantum field
theories that are not conformally invariant.


title:
Lefschetz-thimble approach to the Silver Blaze problem of one-site
  fermion model

abstract:
  The sign problem of finite-density QCD at the zero temperature becomes very
severe if the quark chemical potential exceeds half of the pion mass. In order
to understand its property, we consider the sign problem of the one-site
fermion model appearing in its path-integral expression by using the
Lefschetz-thimble method. We show that the original integration cycle becomes
decomposed into multiple Lefschetz thimbles at a certain value of the fermion
chemical potential, which would correspond to half of the pion mass of
finite-density QCD. This triggers a fictitious phase transition on each
Lefschetz thimble, and the interference of complex phases among them plays an
important role for the correct description of the system. We also show that the
complex Langevin method does not work in this situation.


title: Control Synthesis for Nonlinear Optimal Control via Convex Relaxations

abstract:
  This paper addresses the problem of control synthesis for nonlinear optimal
control problems in the presence of state and input constraints. The presented
approach relies upon transforming the given problem into an
infinite-dimensional linear program over the space of measures. To generate
approximations to this infinite-dimensional program, a sequence of
Semi-Definite Programs (SDP)s is formulated in the instance of polynomial cost
and dynamics with semi-algebraic state and bounded input constraints. A method
to extract a polynomial control function from each SDP is also given. This
paper proves that the controller synthesized from each of these SDPs generates
a sequence of values that converge from below to the value of the optimal
control of the original optimal control problem. In contrast to existing
approaches, the presented method does not assume that the optimal control is
continuous while still proving that the sequence of approximations is optimal.
Moreover, the sequence of controllers that are synthesized using the presented
approach are proven to converge to the true optimal control. The performance of
the presented method is demonstrated on three examples.


title: Optimal Portfolios of Illiquid Assets

abstract:
  This paper investigates the investment behaviour of a large unregulated
financial institution (FI) with CARA risk preferences. It shows how the FI
optimizes its trading to account for market illiquidity using an extension of
the Almgren-Chriss market impact model of multiple risky assets. This expected
utility optimization problem over the set of adapted strategies turns out to
have the same solutions as a mean-variance optimization over deterministic
trading strategies. That means the optimal adapted trading strategy is both
deterministic and time-consistent. It is also found to have an explicit closed
form that clearly displays interesting properties. For example, the classic
constant Merton portfolio strategy, a particular solution of the frictionless
limit of the problem, behaves like an attractor in the space of more general
solutions. The main effect of temporary market impact is to slow down the speed
of convergence to this constant Merton portfolio. The effect of permanent
market impact is to incentivize the FI to buy additional risky assets near the
end of the period. This property, that we name the Ponzi property, is related
to the creation and bursting of bubbles in the market. The proposed model can
be used as a stylized dynamic model of a typical FI in the study of the asset
fire sale channel relevant to understanding systemic risk and financial
stability.


title: Algebraic elliptic cohomology and flops II: $SL$-cobordism

abstract:
  In this paper, we study the algebraic cobordism spectrum $MSL$ in the motivic
stable homotopy category of Voevodsky over an arbitrary perfect field $k$.
Using the motivic Adams spectral sequence, we compute the geometric part of the
$\eta$-completion of $MSL$ (modulo the maximal subgroup that is $l$-divisble
for all primes $l\neq2, char k$). As an application, we study the Krichever's
elliptic genus with integral coefficients, restricted to $MSL$. We determine
its image, and identify its kernel as the ideal generated by differences of
$SL$-flops. This was proved by B. Totaro in the complex analytic setting. In
the appendix, we prove some convergence properties of the motivic Adams
spectral sequence.


title:
A fast spectral method for the Boltzmann collision operator with general
  collision kernels

abstract:
  We propose a simple fast spectral method for the Boltzmann collision operator
with general collision kernels. In contrast to the direct spectral method
\cite{PR00, GT09} which requires $O(N^6)$ memory to store precomputed weights
and has $O(N^6)$ numerical complexity, the new method has complexity
$O(MN^4\log N)$, where $N$ is the number of discretization points in each of
the three velocity dimensions and $M$ is the total number of discretization
points on the sphere and $M\ll N^2$. Furthermore, it requires no precomputation
for the variable hard sphere (VHS) model and only $O(MN^4)$ memory to store
precomputed functions for more general collision kernels. Although a faster
spectral method is available \cite{MP06} (with complexity $O(MN^3\log N)$), it
works only for hard sphere molecules, thus limiting its use for practical
problems. Our new method, on the other hand, can apply to arbitrary collision
kernels. A series of numerical tests is performed to illustrate the efficiency
and accuracy of the proposed method.


title: Scaling of Navier-Stokes trefoil reconnection

abstract:
  Perturbed, helical trefoil vortex knots and a set of anti-parallel vortices
are examined numerically to identify the scaling of their helicity and
vorticity norms during reconnection. For the volume-integrated enstrophy
$Z=\int\omega^2 dV$, a new scaling regime is identified for both configurations
where as the viscosity $\nu$ changes, all $\sqrt{\nu}Z(t)$ cross at
$\nu$-independent times $t_x$, identified as when the first reconnection events
end. Self-similar linear collapse of $B_\nu(t)=(\sqrt{\nu}Z)^{-1/2}$ can be
found for $t\lesssim t_x$ by linearly extrapolating $B_\nu(t)$ to zero at
critical times $T_c(\nu)$, then plotting $(T_c(\nu)-t_x)(B_\nu(t)-B_x)$ where
$B_x=B_\nu(t_x)$. The size $\ell^3$ of the periodic domains must be increased
as $\nu$ is decreased to maintain this scaling as implied by known Sobolev
space bounds. The anti-parallel calculations show that the linear collapse of
$B_\nu(t)$ begins with a quick, viscosity-independent exchange of the
circulation $\Gamma$ between the original vortices and the new vortices. Up to
and after the trefoil knots' first reconnection at time $t_x$, their helicity
${\cal H}$ is preserved, validating the experimental centreline helicity
observation of Scheeler et al (2014a). Because the cubic Navier-Stokes velocity
norm $L_3$ barely changes and the Navier-Stokes $\|\omega\|_\infty$ are bounded
by the Euler values, these flows are never singular. Despite this, the
Navier-Stokes $Z$ can, for a brief period, grow faster than the Euler $Z$ and
the following increase in the viscous energy dissipation rate $\epsilon=\nu Z$
shows $\nu$-independent convergence at $t\approx 2t_x$. Taken together, these
results could be a new paradigm whereby smooth solutions without singularities
or roughness could generate a $\nu\to0$ {\it dissipation anomaly} (finite
dissipation in a finite time) as $\ell\to\infty$, as seen in physical turbulent
flows.


title: Deadline Scheduling as Restless Bandits

abstract:
  The problem of stochastic deadline scheduling is considered. A constrained
Markov decision process model is introduced in which jobs arrive randomly at a
service center with stochastic job sizes, rewards, and completion deadlines.
The service provider faces random processing costs, convex non-completion
penalties, and a capacity constraint that limits the simultaneous processing of
jobs. Formulated as a restless multi-armed bandit problem, the stochastic
deadline scheduling problem is shown to be indexable. A closed-form expression
of the Whittle's index is obtained for the case when the processing costs are
constant. An upper bound on the gap-to-optimality for the Whittle's index
policy is obtained, and it is shown that the bound converges to zero as the job
arrival rate and the number of available processors increase simultaneously to
infinity.


title: Spectrum and Structure of Excited Baryons with CLAS

abstract:
  In this contribution we discuss recent results in light quark baryon
spectroscopy involving CLAS data and higher level analysis results from the
partial wave analysis by the Bonn-Gatchina group. New baryon states were
discovered largely based on the open strangeness production channels $\gamma p
\to K^+ \Lambda$ and $\gamma p \to K^+ \Sigma^0$. The data illustrate the great
potential of the kaon-hyperon channel in the discovery of higher mass baryon
resonances in s-channel production. Other channels with discovery potential,
such as $\gamma p \to p \omega$ and $\gamma p \to \phi p$ are also discussed.
In the second part I will demonstrate on data the sensitivity of meson
electroproduction to expose the active degrees of freedom underlying resonance
transitions as a function of the probed distance scale. For several of the
prominent excited states in the lower mass range the short distance behavior is
described by a core of three dressed-quarks with running quark mass, and
meson-baryon contributions make up significant parts of the excitation strength
at large distances. Finally, an outlook is given of baryon resonance physics at
the 12 GeV CEBAF electron accelerator.


title: On L-space knots obtained from unknotting arcs in alternating diagrams

abstract:
  Let $D$ be a diagram of an alternating knot with unknotting number one. The
branched double cover of $S^3$ branched over $D$ is an L-space obtained by half
integral surgery on a knot $K_D$. We denote the set of all such knots $K_D$ by
$\mathcal D$. We characterize when $K_D\in \mathcal D$ is a torus knot, a
satellite knot or a hyperbolic knot. In a different direction, we show that for
a given $n>0$, there are only finitely many L-space knots in $\mathcal D$ with
genus less than $n$.


title: Dynamic Polygon Clouds: Representation and Compression for VR/AR

abstract:
  We introduce the {\em polygon cloud}, also known as a polygon set or {\em
soup}, as a compressible representation of 3D geometry (including its
attributes, such as color texture) intermediate between polygonal meshes and
point clouds. Dynamic or time-varying polygon clouds, like dynamic polygonal
meshes and dynamic point clouds, can take advantage of temporal redundancy for
compression, if certain challenges are addressed. In this paper, we propose
methods for compressing both static and dynamic polygon clouds, specifically
triangle clouds. We compare triangle clouds to both triangle meshes and point
clouds in terms of compression, for live captured dynamic colored geometry. We
find that triangle clouds can be compressed nearly as well as triangle meshes,
while being far more robust to noise and other structures typically found in
live captures, which violate the assumption of a smooth surface manifold, such
as lines, points, and ragged boundaries. We also find that triangle clouds can
be used to compress point clouds with significantly better performance than
previously demonstrated point cloud compression methods. In particular, for
intra-frame coding of geometry, our method improves upon octree-based
intra-frame coding by a factor of 5-10 in bit rate. Inter-frame coding improves
this by another factor of 2-5. Overall, our dynamic triangle cloud compression
improves over the previous state-of-the-art in dynamic point cloud compression
by 33\% or more.


title:
Transient Events in Archival Very Large Array Observations of the
  Galactic Center

abstract:
  The Galactic center has some of the highest stellar densities in the Galaxy
and a range of interstellar scattering properties that may aid in the detection
of new radio-selected transient events. Here we describe a search for radio
transients in the Galactic center using over 200 hours of archival data from
the Very Large Array (VLA) at 5 and 8.4 GHz. Every observation of SgrA* from
1985$-$2005 has been searched using an automated processing and detection
pipeline sensitive to transients with timescales between 30 seconds and five
minutes with a typical detection threshold of $\sim$100 mJy. Eight possible
candidates pass tests to filter false-positives from radio-frequency
interference, calibration errors, and imaging artifacts. Two events are
identified as promising candidates based on the smoothness of their light
curves. Despite the high quality of their light curves, these detections remain
suspect due to evidence of incomplete subtraction of the complex structure in
the Galactic center, and apparent contingency of one detection on reduction
routines. Events of this intensity ($\sim$100 mJy) and duration ($\sim$100 s)
are not obviously associated with known astrophysical sources, and no
counterparts are found in data at other wavelengths. We consider potential
sources, including Galactic center pulsars, dwarf stars, sources like GCRT
J1745-3009, and bursts from X-ray binaries. None can fully explain the observed
transients, suggesting either a new astrophysical source or a subtle imaging
artifact. More sensitive multiwavelength studies are necessary to characterize
these events which, if real, occur with a rate of $14^{+32}_{-12}~{\rm
hr}^{-1}\,{\rm deg}^{-2}$ in the Galactic center.


title:
Rapid solution of the cryo-EM reconstruction problem by frequency
  marching

abstract:
  Determining the three-dimensional structure of proteins and protein complexes
at atomic resolution is a fundamental task in structural biology. Over the last
decade, remarkable progress has been made using "single particle" cryo-electron
microscopy (cryo-EM) for this purpose. In cryo-EM, hundreds of thousands of
two-dimensional images are obtained of individual copies of the same particle,
each held in a thin sheet of ice at some unknown orientation. Each image
corresponds to the noisy projection of the particle's electron-scattering
density. The reconstruction of a high-resolution image from this data is
typically formulated as a nonlinear, non-convex optimization problem for
unknowns which encode the angular pose and lateral offset of each particle.
Since there are hundreds of thousands of such parameters, this leads to a very
CPU-intensive task---limiting both the number of particle images which can be
processed and the number of independent reconstructions which can be carried
out for the purpose of statistical validation.
  Here, we propose a deterministic method for high-resolution reconstruction
that operates in an ab initio manner---that is, without the need for an initial
guess. It requires a predictable and relatively modest amount of computational
effort, by marching out radially in the Fourier domain from low to high
frequency, increasing the resolution by a fixed increment at each step.


title: Seeing into Darkness: Scotopic Visual Recognition

abstract:
  Images are formed by counting how many photons traveling from a given set of
directions hit an image sensor during a given time interval. When photons are
few and far in between, the concept of `image' breaks down and it is best to
consider directly the flow of photons. Computer vision in this regime, which we
call `scotopic', is radically different from the classical image-based paradigm
in that visual computations (classification, control, search) have to take
place while the stream of photons is captured and decisions may be taken as
soon as enough information is available. The scotopic regime is important for
biomedical imaging, security, astronomy and many other fields. Here we develop
a framework that allows a machine to classify objects with as few photons as
possible, while maintaining the error rate below an acceptable threshold. A
dynamic and asymptotically optimal speed-accuracy tradeoff is a key feature of
this framework. We propose and study an algorithm to optimize the tradeoff of a
convolutional network directly from lowlight images and evaluate on simulated
images from standard datasets. Surprisingly, scotopic systems can achieve
comparable classification performance as traditional vision systems while using
less than 0.1% of the photons in a conventional image. In addition, we
demonstrate that our algorithms work even when the illuminance of the
environment is unknown and varying. Last, we outline a spiking neural network
coupled with photon-counting sensors as a power-efficient hardware realization
of scotopic algorithms.


title: O'R Inflation in $F$-term Supergravity

abstract:
  The supersymmetric realization of inflation in $F$-term supergravity is
usually plagued by the well known "$\eta$" problem. In this paper, a broad
class of small-field examples is realized by employing general O' Raifeartaigh
superpotentials, where the moduli is identified as the massless inflaton. For
illustration we present the simplest example in detail, which can be considered
as a generalization of hybrid inflation.


title: NiCl3 Monolayer: Dirac Spin-Gapless Semiconductor and Chern Insulator

abstract:
  The great obstacle for practical applications of the quantum anomalous Hall
(QAH) effect is the lack of suitable QAH materials (Chern insulators) with
large non-trivial band gap, room-temperature magnetic order and high carrier
mobility. The Nickle chloride (NiCl3) monolayer characteristics are
investigated herein using first-principles calculations. It is reported that
NiCl3 monolayers constitute a new class of Dirac materials with Dirac
spin-gapless semiconducting and high-temperature ferromagnetism (~400K). Taking
into account the spin-orbit coupling, the NiCl3 monolayer becomes an intrinsic
insulator with a large non-trivial band gap of ~24 meV, corresponding to an
operating temperature as high as ~280K at which the quantum anomalous Hall
effect could be observed. The calculated large non-trivial gap, high Curie
temperature and single-spin Dirac states reported herein for the NiCl3
monolayer lead us to propose that this material give a great promise for
potential realization of a near-room temperature QAH effect and potential
applications in spintronics. Last but not least the calculated Fermi velocities
of Dirac fermion of about 4x105 m/s indicate very high mobility in NiCl3
monolayers.


title: Majorization of quantum polarization distributions

abstract:
  Majorization provides a rather powerful partial-order classification of
probability distributions depending only on the spread of the statistics, and
not on the actual numerical values of the variable being described. We propose
to apply majorization as a meta-measure of quantum polarization fluctuations,
this is to say of the degree of polarization. We compare the polarization
fluctuations of the most relevant classes of quantum and classical-like states.
In particular we test Lieb's conjecture regarding classical-like states as the
most polarized and a complementary conjecture that the most unpolarized pure
states are the most nonclassical.


title: Prediction of Magnetoelectric behavior in Bi2MnTiO6

abstract:
  We present results from ab initio calculations based on density functional
theory for bismuth-based double perovskite Bi2MnTiO6. Using total energy
calculation with stress and force minimization we have predicted the
equilibrium crystal structure for Bi2MnTiO6 considering potential structures
into the calculation. We have predicted that the ground state of Bi2MnTiO6 will
be a noncentrosymmetric rhombohedral structure with space group R3c. Our spin
polarized calculation for different possible collinear magnetic configurations
we found that Bi2MnTiO6 will be an insulator with G-type antiferromagnetic
ordering in its ground state. The coexistence of both stereochemically active
Bi-6s lone pair and the Ti4+ with d0-ness which bring covalency results in the
stabilization of noncentrosymmetric structure and thus ferroelectricity. Our
orbital projected density of states plot shows that the Mn2+ in Bi2MnTiO6 will
be at high spin state with a spin moment of 4.28 {\mu}B. Hence Bi2MnTiO6 is
predicted to be a magnetoelectric material.


title:
On the Empirical Effect of Gaussian Noise in Under-sampled MRI
  Reconstruction

abstract:
  In Fourier-based medical imaging, sampling below the Nyquist rate results in
an underdetermined system, in which linear reconstructions will exhibit
artifacts. Another consequence of under-sampling is lower signal to noise ratio
(SNR) due to fewer acquired measurements. Even if an oracle provided the
information to perfectly disambiguate the underdetermined system, the
reconstructed image could still have lower image quality than a corresponding
fully sampled acquisition because of the reduced measurement time. The effects
of lower SNR and the underdetermined system are coupled during reconstruction,
making it difficult to isolate the impact of lower SNR on image quality. To
this end, we present an image quality prediction process that reconstructs
fully sampled, fully determined data with noise added to simulate the loss of
SNR induced by a given under-sampling pattern. The resulting prediction image
empirically shows the effect of noise in under-sampled image reconstruction
without any effect from an underdetermined system.
  We discuss how our image quality prediction process can simulate the
distribution of noise for a given under-sampling pattern, including variable
density sampling that produces colored noise in the measurement data. An
interesting consequence of our prediction model is that we can show that
recovery from underdetermined non-uniform sampling is equivalent to a weighted
least squares optimization that accounts for heterogeneous noise levels across
measurements.
  Through a series of experiments with synthetic and in vivo datasets, we
demonstrate the efficacy of the image quality prediction process and show that
it provides a better estimation of reconstruction image quality than the
corresponding fully-sampled reference image.


title: Excited State Mass spectra and Regge trajectories of Bottom Baryons

abstract:
  We present the mass spectra of radial and orbital excited states of singly
heavy bottom baryons; $\Sigma_{b}^{+}, \Sigma_{b}^-, \Xi_b^-, \Xi_b^0,
\Lambda_b^0$ and $\Omega_b^-$. The QCD motivated hypercentral quark model is
employed for the three body description of baryons and the form of confinement
potential is hyper coulomb plus linear. The first order correction to the
confinement potential is also incorporated in this work. The semi-electronic
decay of $\Omega_b$ and $\Xi_b$ are calculated using the spectroscopic
parameters of the baryons. The computed results are compared with other
theoretical predictions as well as with the available experimental
observations. The Regge trajectories are plotted in (n, $M^2$) plane.


title: Implications of Higgs data for the electroweak chiral Lagrangian

abstract:
  In this talk I discuss the interpretation of LHC Higgs measurements within
the electroweak chiral Lagrangian, paying particular attention to the role of
power counting.


title:
Theory of Exceptional Points of Degeneracy in Uniform Coupled-Waveguides
  and Balance of Gain and Loss

abstract:
  We present a transmission line theory of exceptional points of degeneracy
(EPD) in coupled-mode guiding structures, i.e., a theory that illustrates the
characteristics of coupled electromagnetic modes under a special dispersion
degeneracy condition, yet unexplored in the contest of gain and loss. We
demonstrate the concept of Parity-Time ($\cal{PT}$)-symmetry in coupled uniform
waveguides with balanced and symmetric gain and loss and how this condition is
associated with a second order EPD. We show that by introducing gain into
naturally lossy structures provides for the conditions whereby exceptional
points of non-Hermitian degeneracies can be manifested, such as in $\cal{PT}$-
symmetric structures. Furthermore, we also demonstrate that $\cal{PT}$-
symmetry, despite being the method often suggested for obtaining non-Hermitian
degeneracies at optical frequencies, is not a necessary condition and indeed we
show that EPD can be obtained with broken topological symmetry in uniform TLs.
Operating near such special degeneracy conditions leads to potential
performance enhancement in a variety of microwave and optical resonators, and
devices such as distributed oscillators, including lasers, amplifiers,
radiating arrays, pulse compressors, and Qswitching sensors.


title:
Exceptional points of degeneracy and $\cal{PT}$-symmetry in photonic
  coupled chains of scatterers

abstract:
  We demonstrate the existence of exceptional points of degeneracy (EPD) of
periodic eigenstates in non-Hermitian coupled chains of dipolar scatterers.
Guided modes supported by these structures can exhibit an EPD in their
dispersion diagram at which two or more Bloch eigenstates coalesce, in both
their eigenvectors and eigenvalues. We show a second-order modal EPD associated
with the parity-time ($\cal{PT}$) symmetry condition, at which each particle
pair in the double chain exhibits balanced gain and loss. Furthermore, we also
demonstrate a fourth-order EPD occurring at the band edge. Such degeneracy
condition was previously referred to as a degenerate band edge in lossless
anisotropic photonic crystals. Here, we rigorously show it under the occurrence
of gain and loss balance for a discrete guiding system. We identify a more
general regime of gain and loss balance showing that $\cal{PT}$-symmetry is not
necessary to realize EPDs. Furthermore, we investigate the degree of detuning
of the EPD when the geometrical symmetry or balanced condition is broken. These
findings open unprecedented avenues toward superior light localization and
transport with application to high-Q resonators utilized in sensors, filters,
low-threshold switching and lasing.


title:
Oscillator Based on Lumped Double Ladder Circuit with Band Edge
  Degeneracy

abstract:
  An oscillator design based on a periodic, double ladder resonant circuit is
proposed. The circuit exhibits a degenerate band edge (DBE) in the dispersion
diagram of its phase-frequency eigenstates, and possesses unique resonance
features associated with a high Q-factor resonance, compared to a single ladder
or a conventional LC tank circuit. This oscillator is shown to have an
oscillation threshold that is half that of a single LC ladder circuit having
the same total quality factor, and thus is more robust than an LC oscillator in
the presence of losses. It is also shown that the output and amplitude of the
double-ladder oscillator is much less sensitive to the output loading compared
to single-ladder oscillators. We show the analysis and design of such
oscillators that potentially lead to enhancing the efficiency of RF components
and sources.


title: Radio transients from accretion-induced collapse of white dwarfs

abstract:
  We investigate observational properties of accretion-induced collapse (AIC)
of white dwarfs in radio frequencies. If AIC is triggered by accretion from a
companion star, a dense circumstellar medium can be formed around the
progenitor system. Then, the ejecta from AIC collide to the dense circumstellar
medium, making a strong shock. The strong shock can produce synchrotron
emission which can be observed in radio frequencies. Even if AIC occurs as a
result of white dwarf mergers, we argue that AIC may cause fast radio bursts if
a certain condition is satisfied. If AIC forms neutron stars which are so
massive that rotation is required to support themselves (i.e., supramassive
neutron stars), the supramassive neutron stars may immediately lose their
rotational energy by the r-mode instability and collapse to black holes. If the
collapsing supramassive neutron stars are strongly magnetized, they may emit
fast radio bursts as previously suggested. The AIC radio transients from the
single-degenerate systems may be detected in the future radio transient surveys
like Very Large Array Sky Survey or the Square Kilometer Array transient
survey. Because AIC is suggested to be a gravitational wave source,
gravitational waves from AIC may be accompanied by radio-bright transients
which can be used to confirm the AIC origin of observed gravitational waves.


title:
Statistical properties of the Green function in finite size for Anderson
  Localization models with multifractal eigenvectors

abstract:
  For Anderson Localization models with multifractal eigenvectors on disordered
samples containing $N$ sites, we analyze in a unified framework the
consequences for the statistical properties of the Green function. We focus in
particular on the imaginary part of the Green function at coinciding points
$G^I_{xx}(E-i \eta)$ and study the scaling with the size $N$ of the moments of
arbitrary indices $q$ when the broadening follows the scaling
$\eta=\frac{c}{N^{\delta}}$. For the standard scaling regime $\delta=1$, we
find in the two limits $c \ll 1$ and $c \gg 1$ that the moments are governed by
the anomalous exponents $\Delta(q)$ of individual eigenfunctions, without the
assumption of strong correlations between the weights of consecutive
eigenstates at the same point. For the non-standard scaling regimes
$0<\delta<1$, we obtain that the imaginary Green function follows some
Fr\'echet distribution in the typical region, while rare events are important
to obtain the scaling of the moments. We describe the application to the case
of Gaussian multifractality and to the case of linear multifractality.


title: Wald type analysis for spin-one fields in three dimensions

abstract:
  We revisit Walds analysis in the context of spin-one fields in three
dimensions. A key technical difference from Walds is the role played by the
three dimensional completely antisymmetric tensor. We show how this changes the
analysis as well as the result.


title: Liquid-Liquid Critical Point in 3D Many-Body Water Model

abstract:
  Many-body interactions can play a relevant role in water properties. Here we
study by Monte Carlo simulations a coarse-grained model for bulk water that
includes many-body interactions associated to water cooperativity. The model is
efficient and allows us to equilibrate water at extreme low temperatures in a
wide range of pressures. We find the line of temperatures of maximum density at
constant pressure and, at low temperature and high pressure, a phase transition
between high-density liquid and low-density liquid phases. The liquid-liquid
phase transition ends in a critical point. In the supercritical liquid region
we find for each thermodynamic response function a locus of weak maxima at high
temperature and a locus of strong maxima at low temperature, with both loci
converging at the liquid-liquid critical point where they diverge. Comparing
our results with previous works for the phase diagram of a many-body water
monolayer, we observe that the weak maxima of the specific heat are less
evident in bulk and appear only at negative pressures, while we find those of
compressibility and thermal expansion coefficient also at positive pressures in
bulk. However, the strong maxima of compressibility and thermal expansion
coefficient are very sharp for the bulk case. Our results clarify fundamental
properties of bulk water, possibly difficult to detect with atomistic models
not accounting for many-body interactions.


title:
Test of the Formation mechanism of the Broad Line Region in Active
  Galactic Nuclei

abstract:
  The origin of the Broad Line Region (BLR) in active galaxies remains unknown.
It seems to be related to the underlying accretion disk but an efficient
mechanism is required to rise the material from the disk surface without giving
too strong signatures of the outflow in the case of the low ionization lines.
We discuss in detail two proposed mechanisms: (i) radiation pressure acting on
dust in the disk atmosphere creating a failed wind (ii) the gravitational
instability of the underlying disk. We compare the predicted location of the
inner radius of the BLR in those two scenarios with the observed position
obtained from the reverberation studies of several active galaxies. The failed
dusty outflow model well represents the observational data while the
predictions of the self-gravitational instability are not consistent with
observations. The issue remains why actually we do not see any imprints of the
underlying disk instability in the BLR properties.


title:
BEC polaron in harmonic trap potential at weak coupling regime:
  Lee-Low-Pines type approach

abstract:
  We have calculated the zero-temperature binding energy of a single impurity
atom immersed in a Bose-Einstein condensate of ultracold atoms that are trapped
in an axially symmetric harmonic potential, where the impurity interacts with
bosonic atoms in the condensate via a low-energy s-wave scattering. In this
case, bosons are excited around the impurity to form a quasiparticle, namely, a
BEC polaron. We have developed a variational method, {\it a la} Lee-Low-Pines
(LLP) theory for electron-phonon systems, for description of the polaron with a
conserved angular momentum around the symmetric axis. It is found in numerical
results that the binding energy between the impurity and the excited bosons
break the degeneracy with respect to the total angular momentum of the polaron.
The angular momentum is partially shared by the excited bosons, which is due to
a mechanism similar to the drag effect on the polaron momentum by a phonon
cloud in the LLP theory.


title: Combination of measurements and the BLUE method

abstract:
  The most accurate method to combine measurement from different experiments is
to build a combined likelihood function and use it to perform the desired
inference. This is not always possible for various reasons, hence approximate
methods are often convenient. Among those, the best linear unbiased estimator
(BLUE) is the most popular, allowing to take into account individual
uncertainties and their correlations. The method is unbiased by construction if
the true uncertainties and their correlations are known, but it may exhibit a
bias if uncertainty estimates are used in place of the true ones, in particular
if those estimated uncertainties depend on measured values. In those cases, an
iterative application of the BLUE method may reduce the bias of the combined
measurement.


title:
Decomposition of functions between Banach spaces in the orthogonality
  equation

abstract:
  Let $E,F$ be Banach spaces. In the case that $F$ is reflexive we give a
description for the solutions $(f,g)$ of the Banach-orthogonality equation
$$\langle f(x),g(\alpha)\rangle=\langle x,\alpha\rangle\hspace{10mm}\forall
x\in E,\forall \alpha\in E^*,$$ where $f:E\rightarrow F,g:E^*\rightarrow F^*$
are two maps. Our result generalizes the recent result of {\L}ukasik and
W\'{o}jcik in the case that $E$ and $F$ are Hilbert spaces.


title: Algebraic properties of chromatic roots

abstract:
  A \emph{chromatic root} is a root of the chromatic polynomial of a graph. Any
chromatic root is an algebraic integer. Much is known about the location of
chromatic roots in the real and complex numbers, but rather less about their
properties as algebraic numbers. This question was the subject of a seminar at
the Isaac Newton Institute in late 2008. The purpose of this paper is to report
on the seminar and subsequent developments.
  We conjecture that, for every algebraic integer $\alpha$, there is a natural
number $n$ such that $\alpha+n$ is a chromatic root. This is proved for
quadratic integers, an extension to cubic integers has been found by Adam Bohn.
The idea is to consider certain special classes of graphs for which the
chromatic polynomial is a product of linear factors and one "interesting"
factor of larger degree. We also report computational results on the Galois
groups of irreducible factors of the chromatic polynomial for some special
graphs. Finally, extensions to the Tutte polynomial are mentioned briefly.


title:
Rational dilation on the symmetrized tridisc: failure, success and
  unknown

abstract:
  The closed symmetrized tridisc $\Gamma_3$ and its distinguished boundary
$b\Gamma_3$ are the sets $\Gamma_3=\{
(z_1+z_2+z_3,z_1z_2+z_2z_3+z_3z_1,z_1z_2z_3): \,|z_i|\leq 1, i=1,2,3
\}\subseteq \mathbb C^3$ $b\Gamma_3=\{
(z_1+z_2+z_3,z_1z_2+z_2z_3+z_3z_1,z_1z_2z_3): \,|z_i|= 1, i=1,2,3 \}\subseteq
\Gamma_3.$ A triple of commuting operators $(S_1,S_2,P)$ defined on a Hilbert
space $\mathcal H$ for which $\Gamma_3$ is a spectral set is called a
$\Gamma_3$-contraction. In this article we show by a counter example that there
are $\Gamma_3$-contractions which do not dilate. It is also shown that under
certain conditions a $\Gamma_3$-contraction can have normal $b\Gamma_3$
dilation. We determine several classes of $\Gamma_3$-contractions which dilate
and show explicit construction of their dilations. A concrete functional model
is provided for the $\Gamma_3$-contractions which dilate. Various
characterizations for $\Gamma_3$-unitaries and $\Gamma_3$-isometries are
obtained; the classes of $\Gamma_3$-unitaries and $\Gamma_3$-isometries are
analogous to the unitaries and isometries in one variable operator theory. Also
we find out a model for the class of pure $\Gamma_3$-isometries. En route we
study the geometry of the sets $\Gamma_3$ and $b\Gamma_3$ and provide variety
of characterizations for them.


title: Vector meson condensation in a pion superfluid

abstract:
  We revisit the suggestion that charged rho-mesons undergo Bose-Einstein
condensation in isospin-rich nuclear matter. Using a simple version of the
Nambu-Jona-Lasinio (NJL) model, we conclude that rho-meson condensation is
either avoided or postponed to isospin chemical potentials much higher than the
rho-meson mass as a consequence of the repulsive interaction with the preformed
pion condensate. In order to support our numerical results, we work out a
linear sigma model for pions and rho-mesons, showing that the two models lead
to similar patterns of medium dependence of meson masses. As a byproduct, we
analyze in detail the mapping between the NJL model and the linear sigma model,
focusing on conditions that must be satisfied for a quantitative agreement
between the models.


title:
Rain structure transfer using an exemplar rain image for synthetic rain
  image generation

abstract:
  This letter proposes a simple method of transferring rain structures of a
given exemplar rain image into a target image. Given the exemplar rain image
and its corresponding masked rain image, rain patches including rain structures
are extracted randomly, and then residual rain patches are obtained by
subtracting those rain patches from their mean patches. Next, residual rain
patches are selected randomly, and then added to the given target image along a
raster scanning direction. To decrease boundary artifacts around the added
patches on the target image, minimum error boundary cuts are found using
dynamic programming, and then blending is conducted between overlapping
patches. Our experiment shows that the proposed method can generate realistic
rain images that have similar rain structures in the exemplar images. Moreover,
it is expected that the proposed method can be used for rain removal. More
specifically, natural images and synthetic rain images generated via the
proposed method can be used to learn classifiers, for example, deep neural
networks, in a supervised manner.


title: Completeness of infinite-dimensional Lie groups in their left uniformity

abstract:
  We prove completeness for the main examples of infinite-dimensional Lie
groups and some related topological groups.


title:
Determining the torus covering factors for a sample of type 1 AGN in the
  local Universe

abstract:
  In the unified scheme of active galactic nuclei, a dusty torus absorbs and
then reprocesses a fraction of the intrinsic luminosity which is emitted at
longer wavelengths. Thus, subject to radiative transfer corrections, the
fraction of the sky covered by the torus as seen from the central source (known
as the covering factor $f_c$) can be estimated from the ratio of the infrared
to the bolometric luminosities of the source as $f_c=L_{\rm torus}/L_{\rm
Bol}$. However, the uncertainty in determining $L_{\rm Bol}$ has made the
estimation of covering factors by this technique difficult, especially for AGN
in the local Universe where the peak of the observed SEDs lies in the UV
(ultraviolet). Here, we determine the covering factors of an X-ray/optically
selected sample of 51 type~1 AGN. The bolometric luminosities of these sources
are derived using a self-consistent, energy-conserving model that estimates the
contribution in the unobservable far-UV region, using multi-frequency data
obtained from SDSS, \textit{XMM-Newton}, \textit{WISE}, 2MASS and UKIDSS. We
derive a mean value of $f_c\sim$0.30 with a dispersion of 0.17. Sample
correlations, combined with simulations, show that $f_c$ is more strongly
anti-correlated with $\lambda_{\rm Edd}$ than with $L_{\rm Bol}$. This points
to large-scale torus geometry changes associated with the Eddington-dependent
accretion flow, rather than a receding torus, with its inner sublimation radius
determined solely by heating from the central source. Furthermore, we do not
see any significant change in the distribution of $f_c$ for sub-samples of
radio-loud sources or Narrow Line Seyfert~1 galaxies (NLS1s), though these
sub-samples are small.


title: MBE growth of self-assisted InAs nanowires on graphene

abstract:
  Self-assisted growth of InAs nanowires on graphene by molecular beam epitaxy
is reported. Nanowires with diameter of ~50 nm and aspect ratio of up to 100
were achieved. The morphological and structural properties of the nanowires
were carefully studied by changing the substrate from bilayer graphene through
buffer layer to quasi-free-standing monolayer graphene. The positional relation
of the InAs NWs with the graphene substrate was determined. A 30{\deg}
orientation configuration of some of the InAs NWs is shown to be related to the
surface corrugation of the graphene substrate. InAs NW-based devices for
transport measurements were fabricated, and the conductance measurements showed
a semi-ballistic behavior. In Josephson junction measurements in the non-linear
regime, Multiple Andreev Reflections were observed, and an inelastic scattering
length of about 900 nm was derived.


title:
Interference as an origin of the peaked noise in accreting X-ray
  binaries

abstract:
  We propose a physical model for the peaked noise in the X-ray power density
spectra of accreting X-ray binaries. We interpret its appearance as an
interference of two Comptonization continua: one coming from the up-scattering
of seed photons from the cold thin disk and the other fed by the synchrotron
emission of the hot flow. Variations of both X-ray components are caused by
fluctuations in mass accretion rate, but there is a delay between them
corresponding to the propagation timescale from the disk Comptonization radius
to the region of synchrotron Comptonization. If the disk and synchrotron
Comptonization are correlated, the humps in the power spectra are harmonically
related and the dips between them appear at frequencies related as odd numbers
1:3:5. If they are anti-correlated, the humps are related as 1:3:5, but the
dips are harmonically related. Similar structures are expected to be observed
in accreting neutron star binaries and supermassive black holes. The delay can
be easily recovered from the frequency of peaked noise and further used to
constrain the combination of the viscosity parameter and disk height-to-radius
ratio $\alpha (H/R)^2$ of the accretion flow. We model multi-peak power spectra
of black hole X-ray binaries GX 339$-$4 and XTE J1748$-$288 to constrain these
parameters.


title:
Linear perturbation analysis of hairy black holes in shift-symmetric
  Horndeski theories: Odd-parity perturbations

abstract:
  We analyze the mode stability of odd-parity perturbations of black holes with
linearly time-dependent scalar hair in shift-symmetric Horndeski theories. We
show that a large class of black hole solutions in these theories suffer from
ghost or gradient instability, while there are some classes of solutions that
are stable under linear odd-parity perturbations in the context of mode
analysis.


title: Design and testing of low temperature part of an UHV SPM microscope

abstract:
  We have developed low temperature part of an ultra high vacuum scanning probe
microscope (UHV-SPM) working at variable temperature within the range from 20 K
to 700 K. To achieve the required temperature range, a flow cooling system
using cryogenic helium (~5 K) as a coolant was designed. The system consists of
a flow cryostat and a flexible low-loss transfer line connecting a Dewar vessel
with the flow cryostat. We have also tested liquid nitrogen (~ 77 K) as an
alternative low-cost coolant. Using nitrogen, the microscope can operate at
temperatures of about 100 K and higher. As the flow of the coolant through the
cryostat can cause thermally induced two-phase flow fluctuations resulting in
instability in temperatures, preliminary tests were done in order to find ways
of avoiding the temperature oscillations and optimising the cooling process.


title:
Wireless Authentication System for Barcode Scanning Using Infrared
  Communication Technique

abstract:
  This paper presents the verified methodology for wireless authentication
system using infrared barcode based scanner. An alternate approach of scanning
a barcode using an infrared communication is implemented here, comprises of a
card on which a barcode is printed is illuminated with an infrared beam. The
reflections from the card are received by an infrared receiver and transmit
them to a remote machine over wireless channel where the retrieve information
is further processed and converted into the corresponding barcode digits which
are further matched against the database stored in the server and the
authenticity of the user is established. The system developed is
cost-effective, efficient, provide double security and robust.


title: Thallium under extreme compression

abstract:
  We present a combined theoretical and experimental study of the high-pressure
behavior of thallium. X-ray diffraction experiments have been carried out at
room temperature up to 125 GPa using diamond-anvil cells, nearly doubling the
pressure range of previous experiments. We have confirmed the hcp-fcc
transition at 3.5 GPa and determined that the fcc structure remains stable up
to the highest pressure attained in the experiments. In addition, HP-HT
experiments have been performed up to 8 GPa and 700 K by using a combination of
x-ray diffraction and a resistively heated diamond-anvil cell. Information on
the phase boundaries is obtained, as well as crystallographic information on
the HT bcc phase. The equation of state for different phases is reported. Ab
initio calculations have also been carried out considering several potential
high-pressure structures. They are consistent with the experimental results and
predict that, among the structures considered in the calculations, the fcc
structure of thallium is stable up to 4.3 TPa. Calculations also predict the
post-fcc phase to have a close-packed orthorhombic structure above 4.3 TPa.


title: A Schwartz-type boundary value problem in a biharmonic plane

abstract:
  A commutative algebra $\mathbb{B}$ over the field of complex numbers with the
bases $\{e_1,e_2\}$ satisfying the conditions $(e_1^2+e_2^2)^2=0$,
$e_1^2+e_2^2\ne 0$, is considered. The algebra $\mathbb{B}$ is associated with
the biharmonic equation. Consider a Schwartz-type boundary value problem on
finding a monogenic function of the type
$\Phi(xe_1+ye_2)=U_{1}(x,y)\,e_1+U_{2}(x,y)\,ie_1+
U_{3}(x,y)\,e_2+U_{4}(x,y)\,ie_2$, $(x,y)\in D$, when values of two components
$U_1$, $U_4$ are given on the boundary of a domain $D$ lying in the Cartesian
plane $xOy$. We develop a method of its solving which is based on expressions
of monogenic functions via corresponding analytic functions of the complex
variable. For a half-plane and for a disk, solutions are obtained in explicit
forms by means of Schwartz-type integrals.


title: Current Induced Resistive State in Fe(Se,Te) Superconducting Nanobridges

abstract:
  We study the current-voltage characteristics of Fe(Se,Te) thin films
deposited on CaF$_2$ substrates in form of nanostrips (width $w\sim\lambda$,
$\lambda$ the London penetration length). In view of a possible application of
these materials to superconductive electronics and micro-electronics we focus
on transport properties in small magnetic field, the one generated by the bias
current. From the characteristics taken at different temperatures we derive
estimates for the pinning potential $U$ and the pinning potential range
$\delta$. Since the sample lines are very narrow, the classical creep flow
model provides a sufficiently accurate interpretation of the data only when the
attractive interaction between magnetic flux lines of opposite sign is taken
into account. The observed voltages and the induced detriment of the critical
current of the nanostrips are compatible with the presence of few tens of
magnetic field lines at the equilibrium and a strongly inhomogeneous current
density distribution. In particular, we argue that the sharp corners defining
the bridge geometry represent points of easy magnetic flux lines injection. The
results are relevant for creep flow analysis in superconducting Fe(Se,Te)
nanostrips.


title: Theory of Gas Phase Scattering and Reactivity for Astrochemistry

abstract:
  Because of the very peculiar conditions of chemistry in many astrophysical
gases (low densities, mostly low temperatures, kinetics-dominated chemical
evolution), great efforts have been devoted to study molecular signatures and
chemical evolution. While experiments are being performed in many laboratories,
it appears that the efforts directed towards theoretical works are not as
strong.
  This report deals with the present status of chemical physics/physical
chemistry theory, for the qualitative and quantitative understanding of
kinetics of molecular scattering, being it reactive or inelastic. By gathering
several types of expertise, from applied mathematics to physical chemistry,
dialog is made possible, as a step towards new and more adapted theoretical
frameworks, capable of meeting the theoretical, methodological and numerical
challenges of kinetics-dominated gas phase chemistry in astrophysical
environments.
  A state of the art panorama is presented, alongside present-day strengths and
shortcomings. However, coverage is not complete, being limited in this report
to actual attendance of the workshop. Some paths towards relevant progress are
proposed.


title:
High pressure crystal growth of the antiperovskite centrosymmetric
  superconductor SrPt3P

abstract:
  Bulk single crystals of SrPt3P have been grown for the first time by a
self-flux method at 2 GPa and 1500 {\deg}C using the cubic-anvil, high-pressure
and high-temperature technique. The grown black crystals were found to have
either a plate-like or pillar-like morphology with maximum dimensions of ~ 1 -
0.6 - 0.3 mm3. According to a goniometric study the crystals are elongated in
the ab-plane with the c-axis perpendicular to the plane. The crystal structure
was confirmed by X-ray diffraction (P4/nmm, # 129, Z = 2, a = b = 5.7927(2)
{\AA}, c = 5.3729(2) {\AA} and V = 180.290(11) {\AA}3). Temperature dependent
susceptibility measurements showed a single-phase behaviour and a
superconducting transition temperature of 8.6 K. This value for single crystals
is slightly higher than that previously reported for polycrystalline SrPt3P.
The sharpness of the susceptibility drop ({\Delta}Tc = 0.07 K) supports a high
homogeneity of obtained crystals.


title:
Evidence of ongoing radial migration in NGC 6754: Azimuthal variations
  of the gas properties

abstract:
  Understanding the nature of spiral structure in disk galaxies is one of the
main, and still unsolved questions in galactic astronomy. However, theoretical
works are proposing new testable predictions whose detection is becoming
feasible with recent development in instrumentation. In particular, streaming
motions along spiral arms are expected to induce azimuthal variations in the
chemical composition of a galaxy at a given galactic radius. In this letter we
analyse the gas content in NGC 6754 with VLT/MUSE data to characterise its 2D
chemical composition and H$\alpha$ line-of-sight velocity distribution. We find
that the trailing (leading) edge of the NGC 6754 spiral arms show signatures of
tangentially-slower, radially-outward (tangentially-faster, radially-inward)
streaming motions of metal-rich (poor) gas over a large range of radii. These
results show direct evidence of gas radial migration for the first time. We
compare our results with the gas behaviour in a $N$-body disk simulation
showing spiral morphological features rotating with a similar speed as the gas
at every radius, in good agreement with the observed trend. This indicates that
the spiral arm features in NGC 6754 may be transient and rotate similarly as
the gas does at a large range of radii.


title: Derived smooth stacks and prequantum categories

abstract:
  The Weil-Kostant integrality theorem states that given a smooth manifold
endowed with an integral complex closed 2-form, then there exists a line bundle
with connection on this manifold with curvature the given 2-form. It also
characterises the moduli space of line bundles with connection that arise in
this way. This theorem was extended to the case of p-forms by Gajer in [Ga]. In
this paper we provide a generalization of this theorem where we replace the
original manifold by a derived smooth Artin stack. Our derived Artin stacks are
geometric stacks on the \'etale (\infty,1)-site of affine derived smooth
manifolds. We introduce the notion of a n-shifted p-preplectic derived smooth
Artin stack in analogy with the algebraic case constructed by
Pantev-To\"en-Vaqui\'e-Vezzosi in [PTVV]. This is a derived smooth Artin stack
endowed with a complex closed (p+1)-form which has been cohomologically shifted
by degree n. It is a far reaching generalization of a p-preplectic manifold
which includes orbifolds and other highly singular objects. We then show that
when its n-shifted p-preplectic form is integral, then there exists a
(p+n-1)-gerbe with p-connection data and curvature corresponding to the
original p-preplectic form. We also provide the characterization of the moduli
stack of gerbes with connections arising in this context. We construct a
canonical functor from the (\infty,1)-category of integral n-shifted
p-preplectic derived smooth Artin stacks to the (\infty,1)-category of linear
(\infty,p+n-1)-categories. When n=0 and p=1, this functor can be thought of
like a cohomology functor in that it associates to a derived presymplectic
smooth Artin stack a linear invariant in the form of a differential graded
module. In the general case we obtain higher prequantum categories which
requires the machinery of linear (\infty,n)-categories.


title: Should Algorithms for Random SAT and Max-SAT be Different?

abstract:
  We analyze to what extent the random SAT and Max-SAT problems differ in their
properties. Our findings suggest that for random $k$-CNF with ratio in a
certain range, Max-SAT can be solved by any SAT algorithm with subexponential
slowdown, while for formulae with ratios greater than some constant, algorithms
under the random walk framework require substantially different heuristics. In
light of these results, we propose a novel probabilistic approach for random
Max-SAT called ProMS. Experimental results illustrate that ProMS outperforms
many state-of-the-art local search solvers on random Max-SAT benchmarks.


title:
Equivalence of Two Contour Prescriptions in Superstring Perturbation
  Theory

abstract:
  Conventional superstring perturbation theory based on the world-sheet
approach gives divergent results for the S-matrix whenever the total center of
mass energy of the incoming particles exceeds the threshold of production of
any final state consistent with conservation laws. Two systematic approaches
have been suggested for dealing with this difficulty. The first one involves
deforming the integration cycles over the moduli space of punctured Riemann
surfaces into complexified moduli space. The second one treats the amplitude as
a sum of superstring field theory Feynman diagrams and deforms the integration
contours over loop energies of the Feynman diagram into the complex plane. In
this paper we establish the equivalence of the two prescriptions to all orders
in perturbation theory. Since the second approach is known to lead to unitary
amplitudes, this establishes the consistency of the first prescription with
unitarity.


title:
Sharp weighted estimates for multi-frequency Calder\'on-Zygmund
  operators

abstract:
  In this paper we study weighted estimates for the multi-frequency
$\omega-$Calder\'{o}n-Zygmund operators $T$ associated with the frequency set
$\Theta=\{\xi_1,\xi_2,\dots,\xi_N\}$ and modulus of continuity $\omega$
satisfying the usual Dini condition. We use the modern method of domination by
sparse operators and obtain bounds $\|T\|_{L^p(w)\rightarrow L^p(w)}\lesssim
N^{|\frac{1}{r}-\frac{1}{2}|}[w]_{\mathbb{A}_{p/r}}^{max(1,\frac{1}{p-r})},~1\leq
r<p<\infty,$ for the exponents of $N$ and $\mathbb{A}_{p/r}$ characteristic
$[w]_{\mathbb{A}_{p/r}}$.


title: A variational approach to resistive relativistic plasmas

abstract:
  We develop an action principle to construct the field equations for a
multi-fluid system containing charge-neutral fluids, plasmas, and dissipation
(via resistive interactions), by combining the standard, Maxwell action and
minimal coupling of the electromagnetic field with a recently developed action
for relativistic dissipative fluids. We use a pull-back formalism from
spacetime to abstract matter spaces to build unconstrained variations for both
the charge-neutral fluids and currents making up the plasmas. Using basic
linear algebra techniques, we show that a general "relabeling" invariance
exists for the abstract matter spaces. With the field equations in place, a
phenomenological model for the resistivity is developed, using as constraints
charge conservation and the Second Law of Thermodynamics. A minimal model for a
system of electrons, protons, and heat is developed using the Onsager procedure
for incorporating dissipation.


title: Informational and entropic criteria of self-organization

abstract:
  The work is devoted to study of the following problem: can we use any
qualitative criteria for realization of such universal phenomenon as
self-organization in open systems? We have defined values of information at
fixed points of probability function of density of information and entropy.
Physical meaning of these values as criteria of self-affinity and
self-similarity in chaotic processes have been explained. We have shown that
self-organization occurs if normalized information entropy S belongs to the
range 0.567<S<0.806. The validity of these findings is confirmed by calculation
of value of S for hierarchical sets of well-known fractals.


title: New physics facing LFU and LFV tests in B physics

abstract:
  Lepton flavor universality in the Standard Model and hints of its violation
in neutral ($R_K$) and charged currents $(R_{D^{(*)}})$ in $B$ decays are
presented. We discuss model independent features as well as several leptoquark
scenarios which are well suited to fit current values of $R_K$ and/or
$R_{D^{(*)}}$.


title: Beyond ideal magnetohydrodynamics: From fibration to 3+1 foliation

abstract:
  We consider a resistive multi-fluid framework from the 3+1 space-time
foliation point-of-view, paying particular attention to issues relating to the
use of multi-parameter equations of state and the associated inversion from
evolved to primitive variables. We highlight relevant numerical issues that
arise for general systems with relative flows. As an application of the new
formulation, we consider a three-component system relevant for hot neutron
stars. In this case we let the baryons (neutrons and protons) move together,
but allow heat and electrons to exhibit relative flow. This reduces the problem
to three momentum equations; overall energy-momentum conservation, a
generalised Ohm's law and a heat equation. Our results provide a hierarchy of
increasingly complex models and prepare the ground for new state-of-the-art
simulations of relevant scenarios in relativistic astrophysics.


title:
Beyond ideal magnetohydrodynamics: Resistive, reactive and relativistic
  plasmas

abstract:
  We develop a new framework for the modelling of charged fluid dynamics in
general relativity. The model, which builds on a recently developed variational
multi-fluid model for dissipative fluids, accounts for relevant effects like
the inertia of both charge currents and heat and, for mature systems, the
decoupling of superfluid components. We discuss how the model compares to
standard relativistic magnetohydronamics and consider the connection between
the fluid dynamics, the microphysics and the underlying equation of state. As
illustrations of the formalism, we consider three distinct two-fluid models
describing i) an Ohm's law for resistive charged flows, ii) a relativistic heat
equation, and iii) an equation representing the momentum of a decoupled
superfluid component. As a more complex example, we also formulate a
three-fluid model which demonstrates the thermo-electric effect. This framework
allows us to model neutron stars (and related systems) at a hierarchy of
increasingly complex levels, and should enable us to make progress on a range
of exciting problems in astrophysics and cosmology.


title: Algebraic Synchronization Trees and Processes

abstract:
  We study algebraic synchronization trees, i.e., initial solutions of
algebraic recursion schemes over the continuous categorical algebra of
synchronization trees. In particular, we investigate the relative expressive
power of algebraic recursion schemes over two signatures, which are based on
those for Basic CCS and Basic Process Algebra, as a means for defining
synchronization trees up to isomorphism as well as modulo bisimilarity and
language equivalence. The expressiveness of algebraic recursion schemes is also
compared to that of the low levels in Caucal's pushdown hierarchy.


title:
The Hubble Space Telescope UV Legacy Survey of Galactic Globular
  Clusters. IX. The Atlas of Multiple Stellar Populations

abstract:
  We use high-precision photometry of red-giant-branch (RGB) stars in 57
Galactic globular clusters (GCs), mostly from the `Hubble Space Telescope (HST)
UV Legacy Survey of Galactic globular clusters', to identify and characterize
their multiple stellar populations. For each cluster the pseudo two-color
diagram (or `chromosome map') is presented, built with a suitable combination
of stellar magnitudes in the F275W, F336W, F438W and F814W filters that
maximizes the separation between multiple populations. In the chromosome map of
most GCs (Type I clusters), stars separate in two distinct groups that we
identify with the first (1G) and the second generation (2G). This
identification is further supported by noticing that 1G stars have primordial
(oxygen-rich, sodium-poor) chemical composition, whereas 2G stars are enhanced
in sodium and depleted in oxygen. This 1G-2G separation is not possible for a
few GCs where the two sequences have apparently merged into an extended,
continuous sequence. In some GCs (Type II clusters) the 1G and/or the 2G
sequences appear to be split, hence displaying more complex chromosome maps.
These clusters exhibit multiple SGBs also in purely optical color-magnitude
diagrams, with the fainter SGB joining into a red RGB which is populated by
stars with enhanced heavy-element abundance. We measure the RGB width by using
appropriate colors and pseudo-colors. When the metallicity dependence is
removed, the RGB width correlates with the cluster mass. The fraction of 1G
stars ranges from ~8% to ~67% and anticorrelates with the cluster mass,
indicating that incidence and complexity of the multiple population phenomenon
both increase with cluster mass.


title: Afforestation in Romania: Realities and Perspectives

abstract:
  Romania's forest cover is at this time below, but quite close to the European
average. Despite that, recent forestry activities tend to be more oriented
towards forest exploitation and not to increase the national forested area. The
general public perception is that afforestation activities are limited only to
NGO's projects and media actions and numerous reports and statements made by
some of these organizations are rather sensational and confusing. This paper
tries to cast more light on this controversial issue, presenting accurate data
and considering the whole context of afforestation-from the history of
afforestation activities in Romania to the recent statements and reports
submitted by the government agencies involved in these particular issues. The
necessity and opportunity of afforestation is also substantiated from the
perspective of reintroduction into production of marginal and degraded land. An
analysis of the situation of funding through the National Rural Development
Programme (2007-2013) measures is performed and possible future directions
regarding afforestation programmes are discussed.


title:
Estimating thermodynamic expectations and free energies in expanded
  ensemble simulations: systematic variance reduction through conditioning

abstract:
  Markov chain Monte Carlo methods are primarily used for sampling from a given
probability distribution and estimating multi-dimensional integrals based on
the information contained in the generated samples. Whenever it is possible,
more accurate estimates are obtained by combining Monte Carlo integration and
integration by numerical quadrature along particular coordinates. We show that
this variance reduction technique, referred to as conditioning in probability
theory, can be advantageously implemented in \emph{expanded ensemble}
simulations. These simulations aim at estimating thermodynamic expectations as
a function of an external parameter that is sampled like an additional
coordinate. Conditioning therein entails integrating along the external
coordinate by numerical quadrature. We prove variance reduction with respect to
alternative standard estimators and demonstrate the practical efficiency of the
technique by estimating free energies and characterizing a structural phase
transition between two solid phases.