title: Weak transient chaos

abstract:
  A phenomenon of weak transient chaos is discussed that is caused by
sub-exponential divergence of trajectories in the basin of a non-chaotic
attractor. Such a regime is not easy to detect, because conventional
characteristics, such as the largest Lyapunov exponent is non-positive. Here we
study, how such a divergence can be exposed and detected. First, we show that
weak transient chaos can be exposed if a small random perturbation is added to
the system, leading to positive values of the largest Lyapunov exponent.
Second, we introduce an alternative definition of the Lyapunov exponent, which
allows us to detect weak transient chaos in the deterministic unperturbed
system. We show that this novel characteristic becomes positive, reflecting
transient chaos. We demonstrate this phenomenon and its detection using a
master-slave system where the master possesses a heteroclinic cycle attractor,
while the slave is the Van-der-Pol-Duffing oscillator possessing a stable limit
cycle.


title: Dynamics of sessile drops. Part 3. Theory of forced oscillations

abstract:
  A partially-wetting sessile drop is driven by a sinusoidal pressure field
that produces capillary waves on the liquid/gas interface. The analysis
presented in Part 1 of this series (Bostwick & Steen 2014) is extended by
computing response diagrams and phase shifts for the viscous droplet, whose
three phase contact-line moves with contact-angle that is a smooth function of
the contact line speed. Viscous dissipation is incorporated through the viscous
potential flow approximation and the critical Ohnesorge number bounding regions
beyond which a given mode becomes over-damped is computed. Davis dissipation
originating from the contact-line speed condition leads to damped oscillations
for drops with finite contact-line mobility, even for inviscid fluids. The
critical mobility and associated driving frequency to generate the largest
Davis dissipation is computed. Lastly, regions of modal coexistence where two
modes can be simultaneously excited by a single forcing frequency are
identified. Predictions compare favorably to related experiments on vibrated
drops.


title:
On Unified Modeling, Canonical Duality-Triality Theory, Challenges and
  Breakthrough in Optimization

abstract:
  A unified model is addressed for general optimization problems in multi-scale
complex systems. Based on necessary conditions and basic principles in physics,
the canonical duality-triality theory is presented in a precise way to include
traditional duality theories and popular methods as special applications. Two
conjectures on NP-hardness are discussed, which should play important roles for
correctly understanding and efficiently solving challenging real-world
problems. Applications are illustrated for both nonconvex continuous
optimization and mixed integer nonlinear programming. Misunderstandings and
confusion on some basic concepts, such as objectivity, nonlinearity,
Lagrangian, and Lagrange multiplier method are discussed and classified.
Breakthrough from recent false challenges by C. Z\u{a}linescu and his
co-workers are addressed. This paper will bridge a significant gap between
optimization and multi-disciplinary fields of applied math and computational
sciences.


title: Scalar and vector self-energies of heavy baryons in nuclear medium

abstract:
  The in-medium sum rules are employed to calculate the shifts in the mass and
residue as well as the scalar and vector self-energies of the heavy $\Lambda_Q,
\Sigma_Q$ and $\Xi_Q$ baryons, with Q being $b$ or $c$ quark. The maximum shift
in mass due to nuclear matter belongs to the $\Sigma_c$ baryon and it is found
to be $\Delta m_{\Sigma_{c}}=-936 ~ MeV$. In the case of residue, it is
obtained that the residue of $\Sigma_b$ baryon is maximally affected by the
nuclear medium with the shift $\Delta \lambda_{\Sigma_b} = -0.014 ~ GeV^3 $.
The scalar and vector self-energies are found to be $\Sigma^{S}_{\Lambda_b} =
653 ~ MeV$, $\Sigma^{S}_{\Sigma_b} = -614 ~ MeV $, $\Sigma^{S}_{\Xi_b} = -17 ~
MeV $, $\Sigma^{S}_{\Lambda_c} = 272 ~ MeV $, $\Sigma^{S}_{\Sigma_c} = -936 ~
MeV $, $\Sigma^{S}_{\Xi_c} = -5 ~ MeV $ and $\Sigma^{\nu}_{\Lambda_b} = 436 \pm
148 ~ MeV $, $\Sigma^{\nu}_{\Sigma_b} = 382 \pm 129 ~MeV $,
$\Sigma^{\nu}_{\Xi_b} =15 \pm 5 ~ MeV$, $\Sigma^{\nu}_{\Lambda_c} = 151 \pm 45
~ MeV $, $\Sigma^{\nu}_{\Sigma_c} = 486 \pm 144 ~ MeV $ and
$\Sigma^{\nu}_{\Xi_c} = 1.391 \pm 0.529 ~ MeV $.


title: Explorations in the theory of partition zeta functions

abstract:
  We introduce and survey results on two families of zeta functions connected
to the multiplicative and additive theories of integer partitions. In the case
of the multiplicative theory, we provide specialization formulas and results on
the analytic continuations of these "partition zeta functions", find unusual
formulas for the Riemann zeta function, prove identities for multiple zeta
values, and see that some of the formulas allow for $p$-adic interpolation. The
second family we study was anticipated by Manin and makes use of modular forms,
functions which are intimately related to integer partitions by universal
polynomial recurrence relations. We survey recent work on these zeta
polynomials, including the proof of their Riemann Hypothesis.


title: ABC random forests for Bayesian parameter inference

abstract:
  This preprint has been reviewed and recommended by Peer Community In
Evolutionary Biology (http://dx.doi.org/10.24072/pci.evolbiol.100036).
Approximate Bayesian computation (ABC) has grown into a standard methodology
that manages Bayesian inference for models associated with intractable
likelihood functions. Most ABC implementations require the preliminary
selection of a vector of informative statistics summarizing raw data.
Furthermore, in almost all existing implementations, the tolerance level that
separates acceptance from rejection of simulated parameter values needs to be
calibrated. We propose to conduct likelihood-free Bayesian inferences about
parameters with no prior selection of the relevant components of the summary
statistics and bypassing the derivation of the associated tolerance level. The
approach relies on the random forest methodology of Breiman (2001) applied in a
(non parametric) regression setting. We advocate the derivation of a new random
forest for each component of the parameter vector of interest. When compared
with earlier ABC solutions, this method offers significant gains in terms of
robustness to the choice of the summary statistics, does not depend on any type
of tolerance level, and is a good trade-off in term of quality of point
estimator precision and credible interval estimations for a given computing
time. We illustrate the performance of our methodological proposal and compare
it with earlier ABC methods on a Normal toy example and a population genetics
example dealing with human population evolution. All methods designed here have
been incorporated in the R package abcrf (version 1.7) available on CRAN.


title: Improving Weakly-Supervised Object Localization By Micro-Annotation

abstract:
  Weakly-supervised object localization methods tend to fail for object classes
that consistently co-occur with the same background elements, e.g. trains on
tracks. We propose a method to overcome these failures by adding a very small
amount of model-specific additional annotation. The main idea is to cluster a
deep network's mid-level representations and assign object or distractor labels
to each cluster. Experiments show substantially improved localization results
on the challenging ILSVC2014 dataset for bounding box detection and the PASCAL
VOC2012 dataset for semantic segmentation.


title:
Two competing interpretations of Kelvin Probe Force Microscopy on
  semiconductors put to test

abstract:
  Kelvin probe force microscopy (KPFM) is a popular tool for studying
properties of semiconductors. However, the interpretation of its results is
complicated by the possibility of so-called band bending and the presence of
surface charges. In this work we study two different interpretations for KPFM
on semiconductors: the contact potential difference (CPD) interpretation, which
interprets the measured potential as the work function difference between the
sample and the probe, and a newer, alternative, interpretation proposed by
Baumgart, Helm and Schmidt (BHS). By performing model calculations we
demonstrate that these models generally lead to very different results. Hence
it is important to decide which one is correct. We demonstrate that BHS
predictions for the Kelvin voltage difference between the $p$ and $n$ parts of
a $pn$-junction are inconsistent with a set of experimental results from the
literature. In addition, the BHS interpretation predicts an independence from
the probe material as well as from surface treatments, which we both find to
disagree with experiment. On the other hand, we present a theoretical argument
for the validity of the CPD interpretation and we show that the CPD
interpretation is able to accommodate all of these experimental results. Thus
we posit that the BHS interpretation is generally not suitable for the analysis
of KPFM on semiconductors and that the CPD interpretation should be used
instead.


title: On the Newton stratification in the good reduction of Shimura varieties

abstract:
  I construct a generalisation of Mantovan's almost product structure to
Shimura varieties of Hodge type with hyperspecial level structure at $p$ and
deduce that the perfection of the Newton strata are pro-\'etale locally
isomorphic to the perfection of the product of a central leaf and a
Rapoport-Zink space. The almost product formula can be extended to obtain an
analogue of Caraiani's and Scholze's generalisation of the almost product
structure for Shimura varieties of Hodge type.


title:
The Complete $O(\alpha_s^2)$ Non-Singlet Heavy Flavor Corrections to the
  Structure Functions $g_{1,2}^{ep}(x,Q^2)$, $F_{1,2,L}^{ep}(x,Q^2)$,
  $F_{1,2,3}^{\nu(\bar{\nu})}(x,Q^2)$ and the Associated Sum Rules

abstract:
  We calculate analytically the flavor non-singlet $O(\alpha_s^2)$ massive
Wilson coefficients for the inclusive neutral current non-singlet structure
functions $F_{1,2,L}^{ep}(x,Q^2)$ and $g_{1,2}^{ep}(x,Q^2)$ and charged current
non-singlet structure functions $F_{1,2,3}^{\nu(\bar{\nu})p}(x,Q^2)$, at
general virtualities $Q^2$ in the deep-inelastic region. Numerical results are
presented. We illustrate the transition from low to large virtualities for
these observables, which may be contrasted to basic assumptions made in the
so-called variable flavor number scheme. We also derive the corresponding
results for the Adler sum rule, the unpolarized and polarized Bjorken sum rules
and the Gross-Llewellyn Smith sum rule. There are no logarithmic corrections at
large scales $Q^2$ and the effects of the power corrections due to the heavy
quark mass are of the size of the known $O(\alpha_s^4)$ corrections in the case
of the sum rules. The complete charm and bottom corrections are compared to the
approach using asymptotic representations in the region $Q^2 \gg m_{c,b}^2$. We
also study the target mass corrections to the above sum rules.


title: A note on the shortest common superstring of NGS reads

abstract:
  The Shortest Superstring Problem (SSP) consists, for a set of strings S =
{s_1,...,s_n}, to find a minimum length string that contains all s_i, 1 <= i <=
k, as substrings. This problem is proved to be NP-Complete and APX-hard.
Guaranteed approximation algorithms have been proposed, the current best ratio
being 2+11/23, which has been achieved following a long and difficult quest.
However, SSP is highly used in practice on next generation sequencing (NGS)
data, which plays an increasingly important role in sequencing. In this note,
we show that the SSP approximation ratio can be improved on NGS reads by
assuming specific characteristics of NGS data that are experimentally verified
on a very large sampling set.


title:
A deep convolutional neural network approach to single-particle
  recognition in cryo-electron microscopy

abstract:
  Background: Single-particle cryo-electron microscopy (cryo-EM) has become a
popular tool for structural determination of biological macromolecular
complexes. High-resolution cryo-EM reconstruction often requires hundreds of
thousands of single-particle images. Particle extraction from experimental
micrographs thus can be laborious and presents a major practical bottleneck in
cryo-EM structural determination. Existing computational methods of particle
picking often use low-resolution templates as inputs for particle matching,
making it possible to cause reference-dependent bias. It is critical to develop
a highly efficient template-free method to automatically recognize particle
images from cryo-EM micrographs. Results: We developed a deep learning-based
algorithmic framework, DeepEM, for single-particle recognition from noisy
cryo-EM micrographs, enabling automated particle picking, selection and
verification in an integrated fashion. The kernel of DeepEM is built upon a
convolutional neural network (CNN) of eight layers, which can be recursively
trained to be highly "knowledgeable". Our approach exhibits improved
performance and high precision when tested on the standard KLH dataset.
Application of DeepEM to several challenging experimental cryo-EM datasets
demonstrates its capability in avoiding selection of un-wanted particles and
non-particles even when true particles contain fewer features. Conclusions: The
DeepEM method derived from a deep CNN allows automated particle extraction from
raw cryo-EM micrographs in the absence of templates, which demonstrated
improved performance, objectivity and accuracy. Application of this novel
approach is expected to free the labor involved in single-particle
verification, thus promoting the efficiency of cryo-EM data processing.


title:
Linearly Polarized Millimeter and Submillimeter Continuum Emission of
  Sgr A* Constrained by ALMA

abstract:
  Our aim is to characterize the polarized continuum emission properties
including intensity, polarization position angle, and polarization percentage
of Sgr A* at $\sim$100 (3.0 mm), $\sim$230 (1.3 mm), $\sim$345 (0.87 mm),
$\sim$500 (0.6 mm), and $\sim$700 GHz (0.43 mm). We report continuum emission
properties of Sgr A* at the above frequency bands, based on the Atacama Large
Millimeter Array (ALMA) observations. We measured flux densities of Sgr A* from
ALMA single pointing and mosaic observations. We performed sinusoidal fittings
to the observed (XX-YY)/I intensity ratios, to derive the polarization position
angles and polarization percentages. We successfully detect polarized continuum
emission from all observed frequency bands. We observed lower Stokes I
intensity at $\sim$700 GHz than that at $\sim$500 GHz, which suggests that
emission at $\gtrsim$500 GHz is from optically thin part of a synchrotron
emission spectrum. Both the Stokes I intensity and the polarization position
angle at our highest observing frequency of $\sim$700 GHz, may be varying with
time. However, we do not yet detect variation in the polarization percentage at
$>$500 GHz. The polarization percentage at $\sim$700 GHz is likely lower than
that at $\sim$500 GHz. By comparing the $\sim$500 GHz and $\sim$700 GHz
observations with the observations at lower frequency bands, we suggest that
the intrinsic polarization position angle of Sgr A* is varying with time. This
paper also reports the measurable polarization properties from the observed
calibration quasars. The future simultaneous multi-frequency polarization
observations are required for clarifying the time and frequency variation of
polarization position angle and polarization percentage.


title: Elections in Russia, 1991-2008

abstract:
  In this paper, I review the main trends in voting in national elections in
Russia since 1991, discuss the evidence of manipulation or falsification by the
authorities, and use statistical techniques to examine the determinants of
voting trends.


title: Partitions of planar point sets into polygons

abstract:
  In this paper, we characterize planar point sets that can be partitioned into
disjoint polygons of arbitrarily specified sizes. We provide an algorithm to
construct such a partition, if it exists, in polynomial time. We show that this
problem is equivalent to finding a specified $2$-factor in the visibility graph
of the point set. The characterization for the case where all cycles have
length $3$ also translates to finding a $K_3$-factor of the visibility graph of
the point set. We show that the generalized problem of finding a $K_k$-factor
of the visibility graph of a given point set for $k \geq 5$ is NP-hard.


title: Five years of density matrix embedding theory

abstract:
  Density matrix embedding theory (DMET) describes finite fragments in the
presence of a surrounding environment. In contrast to most embedding methods,
DMET explicitly allows for quantum entanglement between both. In this chapter,
we discuss both the ground-state and response theory formulations of DMET, and
review several applications. In addition, a proof is given that the local
density of states can be obtained by working with a Fock space of bath
orbitals.


title:
The Davies method revisited for heat kernel upper bounds of regular
  Dirichlet forms on metric measure spaces

abstract:
  We apply the Davies method to prove that for any regular Dirichlet form on a
metric measure space, an off-diagonal stable-type upper bound of the heat
kernel is equivalent to the conjunction of the on-diagonal upper bound, a
cutoff inequality on any two concentric balls, and the jump kernel upper bound,
for any walk dimension. If in addition the jump kernel vanishes, that is, if
the Dirichlet form is strongly local, we obtain sub-Gaussian upper bound. This
gives a unified approach to obtaining heat kernel upper bounds for both the
non-local and the local Dirichlet forms.


title: Stealing PINs via Mobile Sensors: Actual Risk versus User Perception

abstract:
  In this paper, we present the actual risks of stealing user PINs by using
mobile sensors versus the perceived risks by users. First, we propose
PINlogger.js which is a JavaScript-based side channel attack revealing user
PINs on an Android mobile phone. In this attack, once the user visits a website
controlled by an attacker, the JavaScript code embedded in the web page starts
listening to the motion and orientation sensor streams without needing any
permission from the user. By analysing these streams, it infers the user's PIN
using an artificial neural network. Based on a test set of fifty 4-digit PINs,
PINlogger.js is able to correctly identify PINs in the first attempt with a
success rate of 74% which increases to 86 and 94% in the second and third
attempts, respectively. The high success rates of stealing user PINs on mobile
devices via JavaScript indicate a serious threat to user security. With the
technical understanding of the information leakage caused by mobile phone
sensors, we then study users' perception of the risks associated with these
sensors. We design user studies to measure the general familiarity with
different sensors and their functionality, and to investigate how concerned
users are about their PIN being discovered by an app that has access to all
these sensors. Our studies show that there is significant disparity between the
actual and perceived levels of threat with regard to the compromise of the user
PIN. We confirm our results by interviewing our participants using two
different approaches, within-subject and between-subject, and compare the
results. We discuss how this observation, along with other factors, renders
many academic and industry solutions ineffective in preventing such side
channel attacks.


title: Spectra of heavy-light mesons in a relativistic model

abstract:
  The spectra and wave functions of heavy-light mesons are calculated within a
relativistic quark model, which is based on a heavy-quark expansion of the
instantaneous Bethe-Salpeter equation by applying the Foldy-Wouthuysen
transformation. The kernel we choose is the standard combination of linear
scalar and Coulombic vector. The effective Hamiltonian for heavy-light
quark-antiquark system is calculated up to order $1/m_Q^2$. Our results are in
good agreement with available experimental data except for the anomalous
$D_{s0}^*(2317)$ and $D_{s1}(2460)$ states. The newly observed heavy-light
meson states can be accommodated successfully in the relativistic quark model
with their assignments presented. The $D_{sJ}^*(2860)$ can be interpreted as
the $|1^{3/2}D_1\rangle$ and $|1^{5/2}D_3\rangle$ states being members of the
1D family with $J^P=1^-$ and $3^-$.


title:
Efficient Algorithms for Time- and Cost-Bounded Probabilistic Model
  Checking

abstract:
  In the design of probabilistic timed systems, bounded requirements concerning
behaviour that occurs within a given time, energy, or more generally cost
budget are of central importance. Traditionally, such requirements have been
model-checked via a reduction to the unbounded case by unfolding the model
according to the cost bound. This exacerbates the state space explosion problem
and significantly increases runtime. In this paper, we present three new
algorithms to model-check time- and cost-bounded properties for Markov decision
processes and probabilistic timed automata that avoid unfolding. They are based
on a modified value iteration process, on an enumeration of schedulers, and on
state elimination techniques. We can now obtain results for any cost bound on a
single state space no larger than for the corresponding unbounded or
expected-value property. In particular, we can naturally compute the cumulative
distribution function at no overhead. We evaluate the applicability and compare
the performance of our new algorithms and their implementation on a number of
case studies from the literature.


title:
Caccioppoli--type estimates and Hardy--type inequalities derived from
  degenerated $p$--harmonic problems

abstract:
  We obtain Caccioppoli--type estimates for nontrivial and nonnegative
solutions to the anticoercive partial differential inequalities of elliptic
type involving degenerated $p$--Laplacian: $-\Delta_{p,a} u:=
-\mathrm{div}(a(x)|\na u|^{p-2}\na u)\ge b(x)\Phi (u)$, where $u$ is defined in
a domain $\Omega$. Using Caccioppoli--type estimates, we obtain several
variants of Hardy--type inequalities in weighted Sobolev spaces.


title: Does the measurement take place when nobody observes it?

abstract:
  We consider {\em non-selective} continuous measurements of a particle
tunneling to a reservoir of finite band-width ($\Lambda$). The particle is
continuously monitored by frequent projective measurements ("quantum
trajectory"), separated by a time-interval $\tau$. A simple analytical
expression for the decay rate has been obtained. For Markovian reservoirs
($\Lambda\to\infty$), no effect of the measurements is found. Otherwise for a
finite $\Lambda$, the decay rate always depends on the measurement time $\tau$.
This result is compared with alternative calculations, with no intermediate
measurements, but when the measurement device is included in the Schr\"odinger
evolution. We found that the detector affects the system by the decoherence
rate ($\Gamma_d$), related to the detector's signal. Although both treatments
are different, the final results become very close for $\tau=2/\Gamma_d$. This
$\tau$ corresponds to the minimal time for which the detector's signal can be
distinguished by an "observer". This indicates a fundamental role of
information in quantum motion and can be used for the extension of the quantum
trajectory method for non-Markovian environments.

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


title:
Collective Strong Coupling with Homogeneous Rabi Frequencies using a 3D
  Lumped Element Microwave Resonator

abstract:
  We design and implement 3D lumped element microwave cavities for the coherent
and uniform coupling to electron spins hosted by nitrogen vacancy centers in
diamond. Our design spatially focuses the magnetic field to a small mode
volume. We achieve large homogeneous single spin coupling rates, with an
enhancement of the single spin Rabi frequency of more than one order of
magnitude compared to standard 3D cavities with a fundamental resonance at
\SI{3}{GHz}. Finite element simulations confirm that the magnetic field
component is homogeneous throughout the entire sample volume, with a RMS
deviation of 1.54\%. With a sample containing $10^{17}$ nitrogen vacancy
electron spins we achieve a collective coupling strength of
$\Omega=\SI{12}{MHz}$, a cooperativity factor $C=27$ and clearly enter the
strong coupling regime. This allows to interface a macroscopic spin ensemble
with microwave circuits, and the homogeneous Rabi frequency paves the way to
manipulate the full ensemble population in a coherent way.


title: Statistical convergence of order $\alpha$ in probability

abstract:
  In this paper ideas of different types of convergence of a sequence of random
variables in probability, namely, statistical convergence of order $\alpha$ in
probability, strong $p$-Ces$\grave{\mbox{a}}$ro summability of order $\alpha$
in probability, lacunary statistical convergence or $S_{\theta}$-convergence of
order $\alpha$ in probability, ${N_{\theta}}$-convergence of order $\alpha$ in
probability have been introduced and their certain basic properties have been
studied.


title:
Nonlinear synthetic gauge potentials and sonic horizons in Bose-Einstein
  condensates

abstract:
  Phonons in a Bose-Einstein condensate can be made to behave as if they
propagate in curved spacetime by controlling the condensate flow speed.
Seemingly disconnected to this, artificial gauge potentials can be induced in
charge neutral atomic condensates by for instance coupling two atomic levels to
a laser field. Here we connect these two worlds and show that synthetic
interacting gauge fields, i.e., density-dependent gauge potentials, induce a
non-trivial spacetime structure for the phonons. This allows for the creation
of new spacetime geometries which depend not on the flow speed of the
condensate but on an easily controlled transverse laser phase. Using this, we
show how to create artificial black holes in a stationary condensate, we
simulate charge in a Reissner-Nordstr\"om black hole and induce cosmological
horizons by creating de Sitter spacetimes. We then show how to combine this de
Sitter spacetime with a black hole, which also opens up the possibility to
study in experiments its quantum stability.


title:
An exact solution to Brownian dynamics of a reversible bimolecular
  reaction in one dimension

abstract:
  Brownian dynamics is a popular fine-grained method for simulating systems of
interacting particles, such as chemical reactions. Though the method is simple
to simulate, it is generally assumed that the dynamics is impossible to solve
exactly and analytically, aside from some trivial systems. We here give the
first exact analytical solution to a non-trivial Brownian dynamics system: the
reaction $A+B\xrightleftharpoons[]{}C$ in equilibrium in one-dimensional
periodic space. The solution is a function of the particles' diffusion
coefficients, radii, length of space and unbinding distance.


title:
Experimental Demonstration of Frequency Regulation by Commercial
  Buildings - Part II: Results and Performance Evaluation

abstract:
  This paper is the second part of a two-part series presenting the results
from an experimental demonstration of frequency regulation in a commercial
building test facility. In Part I, we developed relevant building models and
designed a hierarchical controller for reserve scheduling, building climate
control and frequency regulation.
  In Part II, we introduce the communication architecture and experiment
settings, and present extensive experimental results under frequency
regulation. More specifically, we compute the day-ahead reserve capacity of the
test facility under different assumptions and conditions. Furthermore, we
demonstrate the ability of model predictive control to satisfy comfort
constraints under frequency regulation, and show that fan speed control can
track the fast-moving RegD signal of the Pennsylvania, Jersey, and Maryland
Power Market (PJM) very accurately. In addition, we report the observed effects
of frequency regulation on building control and provide suggestions for
realworld implementation projects. Our results show that hierarchical control
is appropriate for frequency regulation from commercial buildings.


title:
On the dualization of scalars into (d-2)-forms in supergravity. Momentum
  maps, R-symmetry and gauged supergravity

abstract:
  We review and investigate different aspects of scalar fields in supergravity
theories both when they parametrize symmetric spaces and when they parametrize
spaces of special holonomy which are not necessarily symmetric (Kahler and
Quaternionic-Kahler spaces): their role in the definition of derivatives of the
fermions covariant under the R-symmetry group and (in gauged supergravities)
under some gauge group, their dualization into (d-2)-forms, their role in the
supersymmetry transformation rules (via fermion shifts, for instance) etc. We
find a general definition of momentum map that applies to any manifold
admitting a Killing vector and coincides with those of the holomorphic and
tri-holomorphic momentum maps in Kahler and Quaternionic-Kahler spaces and with
an independent definition that can be given in symmetric spaces. We show how
the momentum map occurs ubiquitously: in gauge-covariant derivatives of
fermions, in fermion shifts, in the supersymmetry transformation rules of
(d-2)-forms etc. We also give the general structure of the
Noether-Gaillard-Zumino conserved currents in theories with fields of different
ranks in any dimension.


title:
Time-Invariant Spatially Coupled Low-Density Parity-Check Codes with
  Small Constraint Length

abstract:
  We consider a special family of SC-LDPC codes, that is, time-invariant LDPCC
codes, which are known in the literature for a long time. Codes of this kind
are usually designed by starting from QC block codes, and applying suitable
unwrapping procedures. We show that, by directly designing the LDPCC code
syndrome former matrix without the constraints of the underlying QC block code,
it is possible to achieve smaller constraint lengths with respect to the best
solutions available in the literature. We also find theoretical lower bounds on
the syndrome former constraint length for codes with a specified minimum length
of the local cycles in their Tanner graphs. For this purpose, we exploit a new
approach based on a numerical representation of the syndrome former matrix,
which generalizes over a technique we already used to study a special subclass
of the codes here considered.


title: Some applications and constructions of intertwining operators in LCFT

abstract:
  We discuss some applications of fusion rules and intertwining operators in
the representation theory of cyclic orbifolds of the triplet vertex operator
algebra. We prove that the classification of irreducible modules for the
orbifold vertex algebra W(p)^{A_m} follows from a conjectural fusion rules
formula for the singlet vertex algebra modules. In the p=2 case, we computed
fusion rules for the irreducible singlet vertex algebra modules by using
intertwining operators. This result implies the classification of irreducible
modules for W(2)^{A_m}, conjectured previously in [4]. The main technical tool
is a new deformed realization of the triplet and singlet vertex algebras, which
is used to construct certain intertwining operators that can not be detected by
using standard free field realizations.


title: Backflash light characterization to prevent QKD zero-error hacking

abstract:
  Single photon avalanche diodes (SPADs) are the most commercially diffused
solution for single-photon counting in quantum key distribution (QKD)
applications. However, the secondary photon emission, arising from the
avalanche of charge carriers during a photon detection, may be exploited by an
eavesdropper to gain information without forcing errors in the transmission
key. In this paper, we characterise such backflash light in gated InGaAs/InP
SPADs, and its spectral and temporal characterization for different detector
models and different operating parameters. We qualitatively bound the maximum
information leakage due to backflash light, and propose a solution.


title:
Pairing mechanism of unconventional superconductivity in doped Kane-Mele
  model

abstract:
  We study the pairing symmetry of a doped Kane-Mele model on a honeycomb
lattice with on-site Coulomb interaction. The pairing instability of Cooper
pair is calculated based on the linearized Eliashberg equation within the
random phase approximation (RPA). When the magnitude of the spin-orbit coupling
is weak, even-frequency spin-singlet even-parity (ESE) pairing is dominant. On
the other hand, with the increase of the spin-orbit coupling, we show that the
even-frequency spin-triplet odd-parity (ETO) f-wave pairing exceeds ESE one.
ETO f-wave pairing is supported by the longitudinal spin fluctuation. Since the
transverse spin fluctuation is strongly suppressed by spin-orbit coupling, ETO
f-wave pairing becomes dominant for large magnitude of spin-orbit coupling.


title: Gradient walk and $p$-harmonic functions

abstract:
  We consider a class of stochastic processes and establish its connection to
$p$-harmonic functions. In particular, we obtain stochastic approximations that
converge uniformly to a $p$-harmonic function, with an explicit convergence
rate, and also obtain a precise diffusion representation in continuous time.
The main difficulty is how to deal with the zero set of the gradient of the
underlying function.


title: Beyond generalized Proca theories

abstract:
  We consider higher-order derivative interactions beyond second-order
generalized Proca theories that propagate only the three desired polarizations
of a massive vector field besides the two tensor polarizations from gravity.
These new interactions follow the similar construction criteria to those
arising in the extension of scalar-tensor Horndeski theories to
Gleyzes-Langlois-Piazza-Vernizzi (GLPV) theories. On the isotropic cosmological
background, we show the existence of a constraint with a vanishing Hamiltonian
that removes the would-be Ostrogradski ghost. We study the behavior of linear
perturbations on top of the isotropic cosmological background in the presence
of a matter perfect fluid and find the same number of propagating degrees of
freedom as in generalized Proca theories (two tensor polarizations, two
transverse vector modes, and two scalar modes). Moreover, we obtain the
conditions for the avoidance of ghosts and Laplacian instabilities of tensor,
vector, and scalar perturbations. We observe key differences in the scalar
sound speed, which is mixed with the matter sound speed outside the domain of
generalized Proca theories.


title: Naughton's Wisconsin Bibliography: A Brief Guide

abstract:
  Over nearly three decades at the University of Wisconsin, Jeff Naughton has
left an indelible mark on computer science. He has been a global leader of the
database research field, deepening its core and pushing its boundaries. Many of
Naughton's ideas were translated directly into practice in commercial and
open-source systems. But software comes and goes. In the end, it is the ideas
themselves that have had impact, ideas written down in papers.
  Naughton has been a prolific scholar over the last thirty years, with over
175 publications in his bibliography, covering a wide range of topics. This
document does not attempt to enumerate or even summarize the wealth of ideas
that Naughton has published over the course of his academic career--the task is
too daunting. Instead, the best this short note aims to do is to serve as a
rough map of the territory: something to help other researchers navigate the
wide spaces of Naughton's work.


title: Structure and decay pattern of linear-chain state in 14C

abstract:
  The linear-chain states of $^{14}$C are theoretically investigated by using
the antisymmetrized molecular dynamics. The calculated excitation energies and
the $\alpha$ decay widths of the linear-chain states were compared with the
observed data reported by the recent experiments. The properties of the
positive-parity linear-chain states reasonably agree with the observation, that
convinces us of the linear-chain formation in the positive-parity states. On
the other hand, in the negative-parity states, it is found that the
linear-chain configuration is fragmented into many states and do not form a
single rotational band. As a further evidence of the linear-chain formation, we
focus on the $\alpha$ decay pattern. It is shown that the linear-chain states
decay to the excited states of daughter nucleus $^{10}{\rm Be}$ as well as to
the ground state, while other cluster states dominantly decay into the ground
state. Hence, we regard that this characteristic decay pattern is a strong
signature of the linear-chain formation.


title: On a Diophantine inequality involving a prime and an almost-prime

abstract:
  We prove that there are infinitely many solutions of $$
|\lambda_0+\lambda_1p+\lambda_2P_r|<p^{-\tau}, $$ where $r=3,$
$\tau=\frac1{118}$, and $\lambda_0$ is an arbitrary real number and
$\lambda_1,\lambda_2\in\BR$ with $\lambda_2\neq0$ and
$0>\frac{\lambda_1}{\lambda_2}$ not in $\mathbb{Q}$. This improves a result by
Harman. Moreover, we show that one can require the prime $p$ to be of the form
$\floor{n^c}$ for some positive integer $n$, i.e. $p$ is a Piatetski-Shapiro
prime, with $r=13$ and $\tau=\rho(c),$ a constant explicitly determined by $c$
supported in $\left(1, 1+\frac1{149}\right].$


title:
Electrical control over perpendicular magnetization switching driven by
  spin-orbit torques

abstract:
  Flexible control of magnetization switching by electrical manners is crucial
for applications of spin-orbitronics. Besides of a switching current that is
parallel to an applied field, a bias current that is normal to the switching
current is introduced to tune the magnitude of effective damping-like and
field-like torques and further to electrically control magnetization switching.
Symmetrical and asymmetrical control over the critical switching current by the
bias current with opposite polarities is both realized in Pt/Co/MgO and
$\alpha$-Ta/CoFeB/MgO systems, respectively. This research not only identifies
the influences of field-like and damping-like torques on switching process but
also demonstrates an electrical method to control it.


title: Meter-scale spark X-ray spectrumstatistics

abstract:
  X-ray emission by sparks implies bremsstrahlung from a population of
energetic electrons, but the details of this process remain a mystery. We
present detailed statistical analysis of X-ray spectra detected by multiple
detectors during sparks produced by 1 MV negative high-voltage pulses with 1
$\mu$s risetime. With over 900 shots, we statistically analyze the signals,
assuming that the distribution of spark X-ray fluence behaves as a power law
and that the energy spectrum of X-rays detectable after traversing $\sim$2 m of
air and a thin aluminum shield is exponential. We then determine the parameters
of those distributions by fitting cumulative distribution functions to the
observations. The fit results match the observations very well if the mean of
the exponential X-ray energy distribution is 86 $\pm$ 7 keV and the spark X-ray
fluence power law distribution has index -1.29 $\pm$ 0.04 and spans at least 3
orders of magnitude in fluence.


title: Permutation groups arising from pattern involvement

abstract:
  For an arbitrary finite permutation group $G$, subgroup of the symmetric
group $S_\ell$, we determine the permutations involving only members of $G$ as
$\ell$-patterns, i.e., avoiding all patterns in the set $S_\ell \setminus G$.
The set of all $n$-permutations with this property constitutes again a
permutation group. We consequently refine and strengthen the classification of
sets of permutations closed under pattern involvement and composition that is
due to Atkinson and Beals.


title: A General Characterization of Sync Word for Asynchronous Communication

abstract:
  We study a problem of sequential frame synchronization for a frame
transmitted uniformly in $A$ slots. For a discrete memoryless channel (DMC),
Venkat Chandar et al showed that the frame length $N$ must scale with $A$ as
$e^{N \alpha(Q)} > A$ for the frame synchronization error to go to zero
(asymptotically with $A$). Here, $Q$ denotes the transition probabilities of
the DMC and $\alpha(Q)$, defined as the synchronization threshold,
characterizes the scaling needed of $N$ for asymptotic error free frame
synchronization. We show that the asynchronous communication framework permits
a natural tradeoff between the sync frame length $N$ and the channel (usually
parameterised by the input). For an AWGN channel, we study this tradeoff
between the sync frame length $N$ and the input symbol power $P$ and
characterise the scaling needed of the sync frame energy $E = N P$ for optimal
frame synchronisation.


title: Modelling Interaction of Sentence Pair with coupled-LSTMs

abstract:
  Recently, there is rising interest in modelling the interactions of two
sentences with deep neural networks. However, most of the existing methods
encode two sequences with separate encoders, in which a sentence is encoded
with little or no information from the other sentence. In this paper, we
propose a deep architecture to model the strong interaction of sentence pair
with two coupled-LSTMs. Specifically, we introduce two coupled ways to model
the interdependences of two LSTMs, coupling the local contextualized
interactions of two sentences. We then aggregate these interactions and use a
dynamic pooling to select the most informative features. Experiments on two
very large datasets demonstrate the efficacy of our proposed architecture and
its superiority to state-of-the-art methods.


title: Domain-wall melting as a probe of many-body localization

abstract:
  Motivated by a recent optical-lattice experiment by Choi et al.[Science 352,
1547 (2016)], we discuss how domain-wall melting can be used to investigate
many-body localization. First, by considering noninteracting fermion models, we
demonstrate that experimentally accessible measures are sensitive to
localization and can thus be used to detect the delocalization-localization
transition, including divergences of characteristic length scales. Second,
using extensive time-dependent density matrix renormalization group
simulations, we study fermions with repulsive interactions on a chain and a
two-leg ladder. The extracted critical disorder strengths agree well with the
ones found in existing literature.

categories: cond-mat.quant-gas cond-mat.dis-nn cond-mat.stat-mech cond-mat.str-el


title: Cosmic Neutrinos and Other Light Relics

abstract:
  Cosmological measurements of the radiation density in the early universe can
be used as a sensitive probe of physics beyond the standard model. Observations
of primordial light element abundances have long been used to place non-trivial
constraints on models of new physics and to inform our understanding of the
thermal history to the first few minutes of our present phase of expansion.
Precision measurements of the angular power spectrum of the cosmic microwave
background temperature and polarization will drastically improve our
measurement of the cosmic radiation density over the next decade. These
improved measurements will either uncover new physics or place much more
stringent constraints on physics beyond the standard model, while pushing our
understanding of the early universe to much earlier times.


title:
Eight years of accurate photometric follow-up of transiting giant
  exoplanets

abstract:
  Since 2008 we have run an observational program to accurately measure the
characteristics of known exoplanet systems hosting close-in transiting giant
planets, i.e. hot Jupiters. Our study is based on high-quality photometric
follow-up observations of transit events with an array of medium-class
telescopes, which are located in both the northern and the southern
hemispheres. A high photometric precision is achieved through the
telescope-defocussing technique. The data are then reduced and analysed in a
homogeneous way for estimating the orbital and physical parameters of both the
planets and their parent stars. We also make use of multi-band imaging cameras
for probing planetary atmospheres via the transmission-photometry technique. In
some cases we adopt a two-site observational strategy for collecting
simultaneous light curves of individual transits, which is the only completely
reliable method for truly distinguishing a real astrophysical signal from
systematic noise. In this contribution we review the main results of our
program.


title: An irreducibility criterion for power series

abstract:
  We prove an irreducibility criterion for polynomials with power series
coefficients generalizing previous known results concerning quasi-ordinary
polynomials.


title:
Spectrum Sharing in mmWave Cellular Networks via Cell Association,
  Coordination, and Beamforming

abstract:
  This paper investigates the extent to which spectrum sharing in mmWave
networks with multiple cellular operators is a viable alternative to
traditional dedicated spectrum allocation. Specifically, we develop a general
mathematical framework by which to characterize the performance gain that can
be obtained when spectrum sharing is used, as a function of the underlying
beamforming, operator coordination, bandwidth, and infrastructure sharing
scenarios. The framework is based on joint beamforming and cell association
optimization, with the objective of maximizing the long-term throughput of the
users. Our asymptotic and non-asymptotic performance analyses reveal five key
points: (1) spectrum sharing with light on-demand intra- and inter-operator
coordination is feasible, especially at higher mmWave frequencies (for example,
73 GHz), (2) directional communications at the user equipment substantially
alleviate the potential disadvantages of spectrum sharing (such as higher
multiuser interference), (3) large numbers of antenna elements can reduce the
need for coordination and simplify the implementation of spectrum sharing, (4)
while inter-operator coordination can be neglected in the large-antenna regime,
intra-operator coordination can still bring gains by balancing the network
load, and (5) critical control signals among base stations, operators, and user
equipment should be protected from the adverse effects of spectrum sharing, for
example by means of exclusive resource allocation. The results of this paper,
and their extensions obtained by relaxing some ideal assumptions, can provide
important insights for future standardization and spectrum policy.


title: Low-Rank Matrices on Graphs: Generalized Recovery & Applications

abstract:
  Many real world datasets subsume a linear or non-linear low-rank structure in
a very low-dimensional space. Unfortunately, one often has very little or no
information about the geometry of the space, resulting in a highly
under-determined recovery problem. Under certain circumstances,
state-of-the-art algorithms provide an exact recovery for linear low-rank
structures but at the expense of highly inscalable algorithms which use nuclear
norm. However, the case of non-linear structures remains unresolved. We revisit
the problem of low-rank recovery from a totally different perspective,
involving graphs which encode pairwise similarity between the data samples and
features. Surprisingly, our analysis confirms that it is possible to recover
many approximate linear and non-linear low-rank structures with recovery
guarantees with a set of highly scalable and efficient algorithms. We call such
data matrices as \textit{Low-Rank matrices on graphs} and show that many real
world datasets satisfy this assumption approximately due to underlying
stationarity. Our detailed theoretical and experimental analysis unveils the
power of the simple, yet very novel recovery framework \textit{Fast Robust PCA
on Graphs}


title:
Information Security Awareness at Oman Educational Institutions : An
  Academic Prespective

abstract:
  The gap between the knowledge and the practices regarding the computer and
Internet use are the major factors which influence security of Information. A
survey was performed on the education institutions in Oman to investigate the
level of information security awareness among various entities. The survey
focused on the following factors of IT Security: Demographics, Internet usage,
Awareness about organizations network Security threats experience, Awareness on
Password management, Email security awareness and Knowledge on security
practices. The survey attracted 173 respondents: the level of information
security awareness and knowledge on security practices were correlated and
analyzed. The areas of weakness related to the security implementation,
awareness and practice were identified.


title:
On the Origin of the Charge-Asymmetric Matter. II. Localized Dirac
  Waveforms

abstract:
  This paper continues the author's work \cite{PartI}, where a new framework of
the matter-induced physical geometry was built and an intrinsic nonlinearity of
the Dirac equation discovered. Here, the nonlinear Dirac equation is solved and
the localized configurations are found analytically. Of the two possible types
of the potentially stationary localized configurations of the Dirac field, only
one is stable with respect to the action of an external field and it
corresponds to a positive charge. A connection with the global charge asymmetry
of matter in the Universe and with the recently observed excess of the cosmic
positrons is discussed.


title:
The Rotation of the halo of NGC 6822 from the radial velocities of
  carbon stars

abstract:
  Using spectra taken with the AAOmega spectrograph, we measure the radial
velocities of over 100 stars, many of which are intermediate age carbon stars,
in the direction of the dwarf irregular galaxy NGC 6822. Kinematic analysis
suggests that the carbon stars in the sample are associated with NGC 6822, and
estimates of its radial velocity and galactic rotation are made from a
star-by-star analysis of its carbon star population. We calculate a
heliocentric radial velocity for NGC 6822 of $-51\pm3$ \kms\ and show that the
population rotates with a mean rotation speed of $11.2\pm2.1$ \kms\ at a mean
distance of 1.1 kpc from the galactic centre, about a rotation axis with a
position angle of $26^\circ\pm13^\circ$, as projected on the sky. This is close
to the rotation axis of the HI gas disk and suggests that NGC 6822 is not a
polar ring galaxy, but is dynamically closer to a late type galaxy. However,
the rotation axis is not aligned with the minor axis of the AGB isodensity
profiles and this remains a mystery.


title: $L^2$ Curvature Bounds on Manifolds with Bounded Ricci Curvature

abstract:
  Consider a Riemannian manifold with bounded Ricci curvature $|\Ric|\leq n-1$
and the noncollapsing lower volume bound $\Vol(B_1(p))>\rv>0$. The first main
result of this paper is to prove that we have the $L^2$ curvature bound
$\fint_{B_1(p)}|\Rm|^2 < C(n,\rv)$, which proves the $L^2$ conjecture. In order
to prove this, we will need to first show the following structural result for
limits. Namely, if $(M^n_j,d_j,p_j) \longrightarrow (X,d,p)$ is a $GH$-limit of
noncollapsed manifolds with bounded Ricci curvature, then the singular set
$\cS(X)$ is $n-4$ rectifiable with the uniform Hausdorff measure estimates
$H^{n-4}\big(\cS(X)\cap B_1\big)<C(n,\rv)$, which in particular proves the
$n-4$-finiteness conjecture of Cheeger-Colding. We will see as a consequence of
the proof that for $n-4$ a.e. $x\in \cS(X)$ that the tangent cone of $X$ at $x$
is unique and isometric to $\dR^{n-4}\times C(S^3/\Gamma_x)$ for some
$\Gamma_x\subseteq O(4)$ which acts freely away from the origin.


title: The Least Number with Prescribed Legendre Symbols

abstract:
  In this article we estimate the number of integers up to $X$ which can be
represented by a positive-definite, binary integral quadratic form of
discriminant which is small relative to $X$. This follows from understanding
the vector of signs when computing the Legendre symbol of small integers $n$ at
multiple primes.


title:
EFTfitter---A tool for interpreting measurements in the context of
  effective field theories

abstract:
  Over the past years, the interpretation of measurements in the context of
effective field theories has attracted much attention in the field of particle
physics. We present a tool for interpreting sets of measurements in such models
using a Bayesian ansatz by calculating the posterior probabilities of the
corresponding free parameters numerically. An example is given, in which
top-quark measurements are used to constrain anomalous couplings at the
Wtb-vertex.


title:
Path Integral by Space-time Slicing Approximation In Open Bosonic String
  Field

abstract:
  In our paper, we considered how to apply the traditional Feynman path
integral to string field. By constructing the complete set in Fock space of
non-relativistic and relativistic open bosonic string fields, we extended
Feynman path integral to path integral on functional field and use it to
quantize open bosonic string field.


title:
Intrinsic noise profoundly alters the dynamics and steady state of
  morphogen-controlled bistable genetic switches

abstract:
  During tissue development, patterns of gene expression determine the spatial
arrangement of cell types. In many cases, gradients of secreted signaling
molecules - morphogens - guide this process. The continuous positional
information provided by the gradient is converted into discrete cell types by
the downstream transcriptional network that responds to the morphogen. A
mechanism commonly used to implement a sharp transition between two adjacent
cell fates is the genetic toggle switch, composed of cross-repressing
transcriptional determinants. Previous analyses emphasize the steady state
output of these mechanisms. Here, we explore the dynamics of the toggle switch
and use exact numerical simulations of the kinetic reactions, the Chemical
Langevin Equation, and Minimum Action Path theory to establish a framework for
studying the effect of gene expression noise on patterning time and boundary
position. This provides insight into the time scale, gene expression
trajectories and directionality of stochastic switching events between cell
states. Taking gene expression noise into account predicts that the final
boundary position of a morphogen-induced toggle switch, although robust to
changes in the details of the noise, is distinct from that of the deterministic
system. Moreover, stochastic switching introduces differences in patterning
time along the morphogen gradient that result in a patterning wave propagating
away from the morphogen source. The velocity of this wave is influenced by
noise; the wave sharpens and slows as it advances and may never reach steady
state in a biologically relevant time. This could explain experimentally
observed dynamics of pattern formation. Together the analysis reveals the
importance of dynamical transients for understanding morphogen-driven
transcriptional networks and indicates that gene expression noise can
qualitatively alter developmental patterning.


title:
A Distributed Quaternion Kalman Filter With Applications to Fly-by-Wire
  Systems

abstract:
  The introduction of automated flight control and management systems have made
possible aircraft designs that sacrifice arodynamic stability in order to
incorporate stealth technology intro their shape, operate more efficiently, and
are highly maneuverable. Therefore, modern flight management systems are
reliant on multiple redundant sensors to monitor and control the rotations of
the aircraft. To this end, a novel distributed quaternion Kalman filtering
algorithm is developed for tracking the rotation and orientation of an aircraft
in the three-dimensional space. The algorithm is developed to distribute
computation among the sensors in a manner that forces them to consent to a
unique solution while being robust to sensor and link failure, a desirable
characteristic for flight management systems. In addition, the underlying
quaternion-valued state space model allows to avoid problems associated with
gimbal lock. The performance of the developed algorithm is verified through
simulations.


title: Scale-invariant jet suppression across the black hole mass scale

abstract:
  We provide a schematic framework for understanding observations of jet
suppression in soft state black hole X-ray binaries based on the
Blandford-Payne process and the net magnetic flux threading the black hole. Due
to the geometrical thinness of soft state disks, mass-loading of field lines is
ineffective compared to both geometrically thick disks as well as thin disks
with greater black hole threading flux, a simple physical picture that allows
us to understand the weakness of jets in radiatively efficient thin disks
accreting in the prograde direction around high-spinning black holes. Despite a
simplicity that forbids insights into the complexity of turbulent-driven
evolution or the physics of the observed short-term time variability, we show
how the breadth of this framework is such that it can serve as a coarse-grained
foundation for understanding black hole accretion and jet formation across the
mass scale.


title:
MapReduce and Streaming Algorithms for Diversity Maximization in Metric
  Spaces of Bounded Doubling Dimension

abstract:
  Given a dataset of points in a metric space and an integer $k$, a diversity
maximization problem requires determining a subset of $k$ points maximizing
some diversity objective measure, e.g., the minimum or the average distance
between two points in the subset. Diversity maximization is computationally
hard, hence only approximate solutions can be hoped for. Although its
applications are mainly in massive data analysis, most of the past research on
diversity maximization focused on the sequential setting. In this work we
present space and pass/round-efficient diversity maximization algorithms for
the Streaming and MapReduce models and analyze their approximation guarantees
for the relevant class of metric spaces of bounded doubling dimension. Like
other approaches in the literature, our algorithms rely on the determination of
high-quality core-sets, i.e., (much) smaller subsets of the input which contain
good approximations to the optimal solution for the whole input. For a variety
of diversity objective functions, our algorithms attain an
$(\alpha+\epsilon)$-approximation ratio, for any constant $\epsilon>0$, where
$\alpha$ is the best approximation ratio achieved by a polynomial-time,
linear-space sequential algorithm for the same diversity objective. This
improves substantially over the approximation ratios attainable in Streaming
and MapReduce by state-of-the-art algorithms for general metric spaces. We
provide extensive experimental evidence of the effectiveness of our algorithms
on both real world and synthetic datasets, scaling up to over a billion points.


title:
Numerical test of finite-size scaling predictions for the droplet
  condensation-evaporation transition

abstract:
  We numerically study the finite-size droplet condensation-evaporation
transition in two dimensions. We consider and compare two orthogonal
approaches, namely at fixed temperature and at fixed density, making use of
parallel multicanonical simulations. The equivalence between Ising model and
lattice gas allows us to compare to analytical predictions. We recover the
known background density (at fixed temperature) and transition temperature (at
fixed density) in the thermodynamic limit and compare our finite-size
deviations to the predicted leading-order finite-size corrections.


abstract:
  The goal of this article is to study the geometry of Bach-flat noncompact
steady quasi-Einstein manifolds. We show that a Bach-flat noncompact steady
quasi-Einstein manifold $(M^{n},\,g)$ with positive Ricci curvature such that
its potential function has at least one critical point must be a warped product
with Einstein fiber. In addition, the fiber has constant curvature if $n = 4.$


title:
Interaction of a single mode field cavity with the 1D XY model: Energy
  spectrum

abstract:
  In this work we use the fundamental in quantum optics Jaynes-Cummings model
to study the response of spin $\tfrac12$ chain to a single mode of a laser
light falling on one of the spins, a focused interaction model between the
light and the spin chain. For the spin-spin interaction along the chain we use
the XY model. We report here the exact analytical results, obtained with the
help of a computer algebra system, for the energy spectrum in this model for
chains of up to 4 spins with nearest neighbors interactions, either for open or
cyclic chain configurations. Varying the sign and magnitude of the spin
exchange coupling relative to the light-spin interaction we have investigated
both cases of ferromagnetic or antiferromagnetic spin chains.


title:
Near-infrared colors of minor planets recovered from VISTA - VHS survey
  (MOVIS)

abstract:
  The Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer
(WISE) provide information about the surface composition of about 100,000 minor
planets. The resulting visible colors and albedos enabled us to group them in
several major classes, which are a simplified view of the diversity shown by
the few existing spectra. We performed a serendipitous search in VISTA-VHS
observations using a pipeline developed to retrieve and process the data that
corresponds to solar system objects (SSo). The colors and the magnitudes of the
minor planets observed by the VISTA survey are compiled into three catalogs
that are available online: the detections catalog (MOVIS-D), the magnitudes
catalog (MOVIS-M), and the colors catalog (MOVIS-C). They were built using the
third data release of the survey (VISTA VHS-DR3). A total of 39,947 objects
were detected, including 52 NEAs, 325 Mars Crossers, 515 Hungaria asteroids,
38,428 main-belt asteroids, 146 Cybele asteroids, 147 Hilda asteroids, 270
Trojans, 13 comets, 12 Kuiper Belt objects and Neptune with its four
satellites. The colors found for asteroids with known spectral properties
reveal well-defined patterns corresponding to different mineralogies. The
distributions of MOVIS-C data in color-color plots shows clusters identified
with different taxonomic types. All the diagrams that use (Y-J) color separate
the spectral classes more effectively than the (J-H) and (H-Ks) plots used
until now: even for large color errors (<0.1), the plots (Y-J) vs (Y-Ks) and
(Y-J) vs (J-Ks) provide the separation between S-complex and C-complex. The end
members A, D, R, and V-types occupy well-defined regions.


title:
Temperature measurement of a dust particle in a RF plasma GEC reference
  cell

abstract:
  The thermal motion of a dust particle levitated in a plasma chamber is
similar to that described by Brownian motion in many ways. The primary
differences between a dust particle in a plasma system and a free Brownian
particle is that in addition to the random collisions between the dust particle
and the neutral gas atoms, there are electric field fluctuations, dust charge
fluctuations, and correlated motions from the unwanted continuous signals
originating within the plasma system itself. This last contribution does not
include random motion and is therefore separable from the random motion in a
normal temperature measurement. In this paper, we discuss how to separate
random and coherent motion of a dust particle confined in a glass box in a
Gaseous Electronic Conference radio frequency reference cell employing
experimentally determined dust particle fluctuation data analyzed using the
mean square displacement technique.


title: The Stein Str\"omberg Covering Theorem in metric spaces

abstract:
  In \cite{NaTa} Naor and Tao extended to the metric setting the $O(d \log d)$
bounds given by Stein and Str\"omberg for Lebesgue measure in $\mathbb{R}^d$,
deriving these bounds first from a localization result, and second, from a
random Vitali lemma. Here we show that the Stein-Str\"omberg original argument
can also be adapted to the metric setting, giving a third proof. We also weaken
the hypotheses, and additionally, we sharpen the estimates for Lebesgue
measure.


title: The Flavoured BFSS Model at High Temperature

abstract:
  We study the high temperature series expansion of the Berkooz-Douglas matrix
model which describes the D0/D4--brane system. At high temperature the model is
weakly coupled and we develop the series to second order. We check our results
against the high temperature regime of the bosonic model (without fermions) and
find excellent agreement. We track the temperature dependence of the bosonic
model and find backreaction of the fundamental fields lifts the zero
temperature adjoint mass degeneracy. In the low temperature phase the system is
well described by a gaussian model with three masses $m^t_A=1.964 \pm 0.003$,
$m^l_A=2.001 \pm 0.003$ and $m_f=1.463 \pm 0.001$, the adjoint longitudional
and transverse masses and the mass of the fundamental fields respectively.


title: Adjacent vertices can be hard to find by quantum walks

abstract:
  Quantum walks have been useful for designing quantum algorithms that
outperform their classical versions for a variety of search problems. Most of
the papers, however, consider a search space containing a single marked element
only. We show that if the search space contains more than one marked element,
their placement may drastically affect the performance of the search. More
specifically, we study search by quantum walks on general graphs and show a
wide class of configurations of marked vertices, for which search by quantum
walk needs $\Omega(N)$ steps, that is, it has no speed-up over the classical
exhaustive search. The demonstrated configurations occur for certain placements
of two or more adjacent marked vertices. The analysis is done for the
two-dimensional grid and hypercube, and then is generalized for any graph.


title: Packing graphs of bounded codegree

abstract:
  Two graphs $G_1$ and $G_2$ on $n$ vertices are said to pack if there exist
injective mappings of their vertex sets into $[n]$ such that the images of
their edge sets are disjoint. A longstanding conjecture due to Bollob\'as and
Eldridge and, independently, Catlin, asserts that, if $(\Delta_1(G)+1)
(\Delta_2(G)+1) \le n+1$, then $G_1$ and $G_2$ pack. We consider the validity
of this assertion under the additional assumption that $G_1$ or $G_2$ has
bounded codegree. In particular, we prove for all $t \ge 2$ that, if $G_1$
contains no copy of the complete bipartite graph $K_{2,t}$ and $\Delta_1 > 17 t
\cdot \Delta_2$, then $(\Delta_1(G)+1) (\Delta_2(G)+1) \le n+1$ implies that
$G_1$ and $G_2$ pack. We also provide a mild improvement if moreover $G_2$
contains no copy of the complete tripartite graph $K_{1,1,s}$, $s\ge 1$.


title: On the geometry of graphs associated to infinite-type surfaces

abstract:
  Consider a connected orientable surface $S$ of infinite topological type,
i.e. with infinitely-generated fundamental group. We describe the large-scale
geometry of arbitrary connected subgraphs of the arc complex $A(S)$ and curve
complex $C(S)$ of $S$, provided they are invariant under a sufficiently big
subgroup of the mapping class group $Mod(S)$. We obtain a number of
consequences; in particular we recover the main results of J. Bavard and
Aramayona-Fossas-Parlier .


title: Alternator Coins

abstract:
  We introduce a new type of coin: \textit{the alternator}. The alternator can
pretend to be either a real or a fake coin (which is lighter than a real one).
Each time it is put on a balance scale it switches between pretending to be
either a real coin or a fake one.
  In this paper, we solve the following problem: You are given $N$ coins that
look identical, but one of them is the alternator. All real coins weigh the
same. You have a balance scale which you can use to find the alternator. What
is the smallest number of weighings that guarantees that you will find the
alternator?


title: Bayesian Robust Quantile Regression

abstract:
  Traditional Bayesian quantile regression relies on the Asymmetric Laplace
distribution (ALD) mainly because of its satisfactory empirical and theoretical
performances. However, the ALD displays medium tails and it is not suitable for
data characterized by strong deviations from the Gaussian hypothesis. In this
paper, we propose an extension of the ALD Bayesian quantile regression
framework to account for fat-tails using the Skew Exponential Power (SEP)
distribution. Beside having the $\tau$-level quantile as parameter, the SEP
distribution has an additional key parameter governing the decay of the tails,
making it attractive for robust modeling of conditional quantiles at different
confidence levels. Linear and Generalized Additive Models (GAM) with penalized
spline are considered to show the flexibility of the SEP in the Bayesian
quantile regression context. Lasso priors are considered in both cases to
account for shrinking parameters problem when the parameters space becomes
wide. To implement the Bayesian inference we propose a new adaptive
Metropolis--Hastings algorithm in the linear model and an adaptive Metropolis
within Gibbs one in the GAM framework. Empirical evidence of the statistical
properties of the proposed SEP Bayesian quantile regression method is provided
through several example based on simulated and real dataset.


title:
New analytical solutions for chemical evolution models: characterizing
  the population of star-forming and passive galaxies

abstract:
  Analytical models of chemical evolution, including inflow and outflow of gas,
are important tools to study how the metal content in galaxies evolves as a
function of time. In this work, we present new analytical solutions for the
evolution of the gas mass, total mass and metallicity of a galactic system,
when a decaying exponential infall rate of gas and galactic winds are assumed.
We apply our model to characterize a sample of local star-forming and passive
galaxies from the Sloan Digital Sky Survey data, with the aim of reproducing
their observed mass-metallicity relation; in this way, we can derive how the
two populations of star-forming and passive galaxies differ in their particular
distribution of ages, formation time scales, infall masses and mass loading
factors. We find that the local passive galaxies are on average older and
assembled on shorter typical time-scales than the local star-forming ones; on
the other hand, the larger mass star-forming galaxies show generally older ages
and longer typical formation time-scales compared with the smaller mass
star-forming galaxies. Finally, we conclude that the local star-forming
galaxies experience stronger galactic winds than the passive galaxy population.
We explore the effect of assuming different initial mass functions in our
model, showing that to reproduce the observed mass-metallicity relation
stronger winds are requested if the initial mass function is top-heavy.
Finally, our analytical models predict the assumed sample of local galaxies to
lie on a tight surface in the 3D space defined by stellar metallicity, star
formation rate and stellar mass, thus mimicking the well-known "fundamental
relation".


title: Rough differential equations with unbounded drift term

abstract:
  We study controlled differential equations driven by a rough path (in the
sense of T. Lyons) with an additional, possibly unbounded drift term. We show
that the equation induces a solution flow if the drift grows at most linearly.
Furthermore, we show that the semiflow exists assuming only appropriate
one-sided growth conditions. We provide bounds for both the flow and the
semiflow. Applied to stochastic analysis, our results imply "strong
completeness" and the existence of a stochastic (semi)flow for a large class of
stochastic differential equations. If the driving process is Gaussian, we can
further deduce (essentially) sharp tail estimates for the (semi)flow and a
Freidlin-Wentzell-type large deviation result.


title:
Modelling the variable broad-band optical/UV/X-ray spectrum of
  PG1211+143: Implications for the ionized outflow

abstract:
  We present the results from a detailed analysis of the 2007 Swift monitoring
campaign of the quasar PG1211+143. We constructed broad-band, optical/UV/X-ray
spectral energy distributions over three X-ray flux intervals. We fitted them
with a model which accounts for the disc and the X-ray coronal emission and the
warm absorber (well established in this source). The three flux spectra are
well fitted by the model we considered. The disc inner temperature remains
constant at ~2 eV, while X-rays are variable both in spectral slope and
normalization. The absorber covers almost 90% of the central source. It is
outflowing with a velocity less than 2.3*10^4 km/s (3sigma upper limit), and
has a column density of ~10^23.2. Its ionization parameter varies by a factor
of 1.6, and it is in photo-ionizing equilibrium with the ionizing flux. It is
located at a distance of less than 0.35 pc from the central source and its
relative thickness, DR/R is less than 0.1. The absorber' s ionization parameter
variations can explain the larger than average amplitude of the X-ray
variations. The absence of optical/UV variations (consistent with the high
black hole mass estimate) argues against the presence of inward propagating
disc fluctuations and strong X-ray illumination of the disc (in agreement with
the low ratio of X-ray over the bolometric luminosity of ~20-35). We estimate
an upper limit for the mass outflow of ~5 solar masses per year (~2.3 times the
Eddington mass accretion rate). If the outflow rate is indeed that high, then
it must be a short-lived episode in the quasar's life time. Finally, we
estimate an upper limit for the kinetic power of the outflow of ~1.4*10^43
ergs/s. This outflow cannot deploy significant mechanical energy to the
surrounding ISM of the quasar's host galaxy, but is sufficient to heat the ISM
to 10^7 K and to produce a fast decline to the star formation rate of the
galaxy.


title: A Multi-perspective Analysis of Carrier-Grade NAT Deployment

abstract:
  As ISPs face IPv4 address scarcity they increasingly turn to network address
translation (NAT) to accommodate the address needs of their customers.
Recently, ISPs have moved beyond employing NATs only directly at individual
customers and instead begun deploying Carrier-Grade NATs (CGNs) to apply
address translation to many independent and disparate endpoints spanning
physical locations, a phenomenon that so far has received little in the way of
empirical assessment. In this work we present a broad and systematic study of
the deployment and behavior of these middleboxes. We develop a methodology to
detect the existence of hosts behind CGNs by extracting non-routable IP
addresses from peer lists we obtain by crawling the BitTorrent DHT. We
complement this approach with improvements to our Netalyzr troubleshooting
service, enabling us to determine a range of indicators of CGN presence as well
as detailed insights into key properties of CGNs. Combining the two data
sources we illustrate the scope of CGN deployment on today's Internet, and
report on characteristics of commonly deployed CGNs and their effect on end
users.


title:
Mutation via Hovey twin cotorsion pairs and model structures in
  extriangulated categories

abstract:
  We give a simultaneous generalization of exact categories and triangulated
categories, which is suitable for considering cotorsion pairs, and which we
call extriangulated categories. Extension-closed, full subcategories of
triangulated categories are examples of extriangulated categories. We give a
bijective correspondence between some pairs of cotorsion pairs which we call
Hovey twin cotorsion pairs, and admissible model structures. As a consequence,
these model structures relate certain localizations with certain ideal
quotients, via the homotopy category which can be given a triangulated
structure. This gives a natural framework to formulate reduction and mutation
of cotorsion pairs, applicable to both exact categories and triangulated
categories. These results can be thought of as arguments towards the view that
extriangulated categories are a convenient setup for writing down proofs which
apply to both exact categories and (extension-closed subcategories of)
triangulated categories.


title: Solvable Model of a Mixture of Bose-Einstein Condensates

abstract:
  A mixture of two kinds of identical bosons held in a harmonic potential and
interacting by harmonic particle-particle interactions is discussed. This is an
exactly-solvable model of a mixture of two trapped Bose-Einstein condensates
which allows us to examine analytically various properties. Generalizing the
treatment in [Cohen and Lee, J. Math. Phys. {\bf 26}, 3105 (1985)], closed form
expressions for the ground-state energy, wave-function, and lowest-order
densities are obtained and analyzed for attractive and repulsive intra-species
and inter-species particle-particle interactions. A particular mean-field
solution of the corresponding Gross-Pitaevskii theory is also found
analytically. This allows us to compare properties of the mixture at the exact,
many-body and mean-field levels, both for finite systems and at the limit of an
infinite number of particles. We hereby prove that the exact ground-state
energy and lowest-order intra-species and inter-species densities converge at
the infinite-particle limit (when the products of the number of particles times
the intra-species and inter-species interaction strengths are held fixed) to
the results of the Gross-Pitaevskii theory for the mixture. Finally and on the
other end, the separability of the mixture's center-of-mass coordinate is used
to show that the Gross-Pitaevskii theory for mixtures is unable to describe the
variance of many-particle operators in the mixture, even in the
infinite-particle limit. Our analytical results show that many-body
correlations exist in a mixture of Bose-Einstein condensates made of any number
of particles. Implications are briefly discussed.


title:
Temperature- and Size-dependence of Line shape of ESR spectra of XXZ
  antiferromagnetic chain

abstract:
  The ESR (Electron Spin Resonance) spectrum of the XXZ spin chain with finite
length shows a double-peak structure at high temperatures around the EPR
(Electron Paramagnetic Resonance) resonance frequency. This fact has been
pointed out by direct numerical methods (S. El Shawish, O. Cepas and S.
Miyashita; H. Ikeuchi, H. De Raedt, S. Bertaina and S. Miyashita). On the other
hand, at low temperatures the spectrum has a single peak with a finite shift
from the frequency of EPR as predicted by the analysis of field theoretical
works (M. Oshikawa and I. Affleck). We study how the spectrum changes with the
temperature, and also we study the size-dependence of the line shape including
the even-odd effect. In order to understand those dependences, we introduce a
decomposition of the spectrum into contributions from transitions specified by
magnetization, and we characterize the structure of the spectrum by individual
contributions. Applying the moment method introduced by M. Brockman et al., to
each component, we analyze the size-dependence of the structure of the
spectrum, which supports the numerical observation that separation of the
double-peak structure vanishes inversely with the size.


title: A Short Proof for Gap Independence of Simultaneous Iteration

abstract:
  This note provides a very short proof of a spectral gap independent property
of the simultaneous iterations algorithm for finding the top singular space of
a matrix. See Rokhlin-Szlam-Tygert-2009, Halko-Martinsson-Tropp-2011 and
Musco-Musco-2015. The proof is terse but completely self contained and should
be accessible to the linear algebra savvy reader.


title:
A theoretical perspective on the formation and fragmentation of
  protostellar discs

abstract:
  We discuss the factors influencing the formation and gravitational
fragmentation of protostellar discs. We start with a review of how observations
of prestellar cores can be analysed statistically to yield plausible initial
conditions for simulations of their subsequent collapse. Simulations based on
these initial conditions show that, despite the low levels of turbulence in
prestellar cores, they deliver primary protostars and associated discs which
are routinely subject to stochastic impulsive perturbations; consequently
misalignment of the spins and orbits of protostars are common. Also, the
simulations produce protostars that collectively have a mass function and
binary statistics matching those observed in nearby star formation regions, but
only if a significant fraction of the turbulent energy in the core is
solenoidal, and accretion onto the primary protostar is episodic with a duty
cycle > 3000 yr. Under this circumstance a core typically spawns between 4 and
5 protostars, with high efficiency, and the lower-mass protostars are mainly
formed by disc fragmentation. The requirement that a proto-fragment in a disc
lose thermal energy on a dynamical timescale dictates that {\bf there is a
sweet spot for} disc fragmentation at radii 70 AU < R < 100 AU and temperatures
10 K < T < 20 K, and this might explain the Brown Dwarf Desert.


title: Labelled tableaux for interpretability logics

abstract:
  In is paper we present a labelled tableau proof system that serves a wide
class of interpretability logics. The system is proved sound and complete for
any interpretability logic characterised by a frame condition given by a set of
universal strict first order Horn sentences. As such, the current paper adds to
a better proof-theoretical understanding of interpretability logics.


title: Rhombic tilings and Bott-Samelson varieties

abstract:
  S.~Elnitsky (1997) gave an elegant bijection between rhombic tilings of
$2n$-gons and commutation classes of reduced words in the symmetric group on
$n$ letters. P.~Magyar (1998) found an important construction of the
Bott-Samelson varieties introduced by H.C.~Hansen (1973) and M.~Demazure
(1974). We explain a natural connection between S.~Elnitsky's and P.~Magyar's
results. This suggests using tilings to encapsulate Bott-Samelson data (in type
$A$). It also indicates a geometric perspective on S.~Elnitsky's combinatorics.
We also extend this construction by assigning desingularizations to the
zonotopal tilings considered by B.~Tenner (2006).


title: Slotless Protocols for Fast and Energy-Efficient Neighbor Discovery

abstract:
  In mobile ad-hoc networks, neighbor discovery protocols are used to find
surrounding devices and to establish a first contact between them. Since the
clocks of the devices are not synchronized and their energy-budgets are
limited, usually duty-cycled, asynchronous discovery protocols are applied.
Only if two devices are awake at the same point in time, they can rendezvous.
Currently, time-slotted protocols, which subdivide time into multiple intervals
with equal lengths (slots), are considered to be the most efficient discovery
schemes. In this paper, we break away from the assumption of slotted time. We
propose a novel, continuous-time discovery protocol, which temporally decouples
beaconing and listening. Each device periodically sends packets with a certain
interval, and periodically listens for a given duration with a different
interval. By optimizing these interval lengths, we show that this scheme can,
to the best of our knowledge, outperform all known protocols such as DISCO,
U-Connect or Searchlight significantly. For example, Searchlight takes up to
740 % longer than our proposed technique to discover a device with the same
duty-cycle. Further, our proposed technique can also be applied in widely-used
asymmetric purely interval-based protocols such as ANT or Bluetooth Low Energy.


title: Bootstrapping the Kaplan-Meier Estimator on the Whole Line

abstract:
  This article is concerned with proving the consistency of Efron's (1981)
bootstrap for the Kaplan-Meier estimator on the whole support of a survival
function. While other works address the asymptotic Gaussianity of the estimator
itself without restricting time (e.g. Gill, 1983, and Ying, 1989), we enable
the construction of bootstrap-based time-simultaneous confidence bands for the
whole survival function. Other practical applications include bootstrap-based
confidence bands for the mean residual life-time function or the Lorenz curve
as well as confidence intervals for the Gini index.


title: How to test for partially predictable chaos

abstract:
  For a chaotic system pairs of initially close-by trajectories become
eventually fully uncorrelated on the attracting set. This process of
decorrelation may split into an initial exponential decrease, characterized by
the maximal Lyapunov exponent, and a subsequent diffusive process on the
chaotic attractor causing the final loss of predictability. The time scales of
both processes can be either of the same or of very different orders of
magnitude. In the latter case the two trajectories linger within a finite but
small distance (with respect to the overall extent of the attractor) for
exceedingly long times and therefore remain partially predictable.
  Tests for distinguishing chaos from laminar flow widely use the time
evolution of inter-orbital correlations as an indicator. Standard tests however
yield mostly ambiguous results when it comes to distinguish partially
predictable chaos and laminar flow, which are characterized respectively by
attractors of fractally broadened braids and limit cycles. For a resolution we
introduce a novel 0-1 indicator for chaos based on the cross-distance scaling
of pairs of initially close trajectories, showing that this test robustly
discriminates chaos, including partially predictable chaos, from laminar flow.
One can use furthermore the finite time cross-correlation of pairs of initially
close trajectories to distinguish, for a complete classification, also between
strong and partially predictable chaos. We are thus able to identify laminar
flow as well as strong and partially predictable chaos in a 0-1 manner solely
from the properties of pairs of trajectories.


title:
Anisotropic thermodynamic and transport properties of single crystalline
  CaKFe$_{4}$As$_{4}$

abstract:
  Single crystalline, single phase CaKFe$_{4}$As$_{4}$ has been grown out of a
high temperature, quaternary melt. Temperature dependent measurements of x-ray
diffraction, anisotropic electrical resistivity, elastoresistivity,
thermoelectric power, Hall effect, magnetization and specific heat, combined
with field dependent measurements of electrical resistivity and field and
pressure dependent measurements of magnetization indicate that
CaKFe$_{4}$As$_{4}$ is an ordered, stoichiometric, Fe-based superconductor with
a superconducting critical temperature, $T_c$ = 35.0 $\pm$ 0.2 K. Other than
superconductivity, there is no indication of any other phase transition for 1.8
K $\leq T \leq$ 300 K. All of these thermodynamic and transport data reveal
striking similarities to that found for optimally- or slightly over-doped
(Ba$_{1-x}$K$_x$)Fe$_2$As$_2$, suggesting that stoichiometric CaKFe$_4$As$_4$
is intrinsically close to what is referred to as "optimal-doped" on a
generalized, Fe-based superconductor, phase diagram. The anisotropic
superconducting upper critical field, $H_{c\text{2}}(T)$, of
CaKFe$_{4}$As$_{4}$ was determined up to 630 kOe. The anisotropy parameter
$\gamma(T)=H_{c\text{2}}^{\perp}/H_{c\text{2}}^{\|}$, for $H$ applied
perpendicular and parallel to the c-axis, decreases from $\simeq 2.5$ at $T_c$
to $\simeq 1.5$ at 25 K which can be explained by interplay of paramagnetic
pairbreaking and orbital effects. The slopes of
$dH_{c\text{2}}^{\|}/dT\simeq-44$ kOe/K and $dH_{c\text{2}}^{\perp}/dT
\simeq-109$ kOe/K at $T_c$ yield an electron mass anisotropy of
$m_{\perp}/m_{\|}\simeq 1/6$ and short Ginzburg-Landau coherence lengths
$\xi_{\|}(0)\simeq 5.8 \text{\AA}$ and $\xi_{\perp}(0)\simeq 14.3 \text{\AA}$.
The value of $H_{c\text{2}}^{\perp}(0)$ can be extrapolated to $\simeq 920$
kOe, well above the BCS paramagnetic limit.


title:
The Collapse of the Wien Tail in the Coldest Brown Dwarf? Hubble Space
  Telescope Near-Infrared Photometry of WISE J085510.83-071442.5

abstract:
  We present Hubble Space Telescope (HST) near-infrared photometry of the
coldest known brown dwarf, WISE J085510.83$-$071442.5 (WISE 0855$-$0714). WISE
0855$-$0714 was observed with the Wide Field Camera 3 (WFC3) aboard HST using
the F105W, F125W, and F160W filters, which approximate the $Y$, $J$, and $H$
near-infrared bands. WISE 0855$-$0714 is undetected at F105W with a
corresponding 2$\sigma$ magnitude limit of $\sim$26.9. We marginally detect
WISE 0855$-$0714 in the F125W images (S/N $\sim$4), with a measured magnitude
of 26.41 $\pm$ 0.27, more than a magnitude fainter than the $J-$band magnitude
reported by Faherty and coworkers. WISE J0855$-$0714 is clearly detected in the
F160W band, with a magnitude of 23.90 $\pm$ 0.02, the first secure detection of
WISE 0855$-$0714 in the near-infrared. Based on these data, we find that WISE
0855$-$0714 has extremely red F105W$-$F125W and F125W$-$F160W colors relative
to other known Y dwarfs. We find that when compared to the models of Saumon et
al. and Morley et al., the F105W$-$F125W and F125W$-$F160W colors of WISE
0855$-$0714 cannot be accounted for simultaneously. These colors likely
indicate that we are seeing the collapse of flux on the Wien tail for this
extremely cold object.


title: Network Hardware-Accelerated Consensus

abstract:
  Consensus protocols are the foundation for building many fault-tolerant
distributed systems and services. This paper posits that there are significant
performance benefits to be gained by offering consensus as a network service
(CAANS). CAANS leverages recent advances in commodity networking hardware
design and programmability to implement consensus protocol logic in network
devices. CAANS provides a complete Paxos protocol, is a drop-in replacement for
software-based implementations of Paxos, makes no restrictions on network
topologies, and is implemented in a higher-level, data-plane programming
language, allowing for portability across a range of target devices. At the
same time, CAANS significantly increases throughput and reduces latency for
consensus operations. Consensus logic executing in hardware can transmit
consensus messages at line speed, with latency only slightly higher than simply
forwarding packets.


title:
Higher order generalization of Fukaya's Morse homotopy invariant of
  3-manifolds II. Invariants of 3-manifolds with $b_1=1$

abstract:
  In this paper, it is explained that a topological invariant for 3-manifold
$M$ with $b_1(M)=1$ can be constructed by applying Fukaya's Morse homotopy
theoretic approach for Chern--Simons perturbation theory to a local system on
$M$ of rational functions associated to the free abelian covering of $M$. Our
invariant takes values in Garoufalidis--Rozansky's space of Jacobi diagrams
whose edges are colored by rational functions. It is expected that our
invariant gives a lot of nontrivial finite type invariants of 3-manifolds.


title: Drag induced radiative energy loss of semi-hard heavy quarks

abstract:
  We revisited gluon bremsstrahlung off a heavy quark in nuclear matter within
higher twist formalism. In this work, we demonstrate that, in addition to
transverse momentum diffusion parameter ($\hat q$), the gluon emission spectrum
for a heavy quark is quite sensitive to $\hat e$, which quantify the amount of
light-cone drag experienced by a parton. This effect leads to an additional
energy loss term for heavy-quarks. From heavy flavor suppression data in
ultra-relativistic heavy-ion collisions one can now estimate the value of this
sub-leading non-perturbative jet transport parameter ($\hat e$) from our
results.


title: Gaussian variational approximation with sparse precision matrices

abstract:
  We consider the problem of learning a Gaussian variational approximation to
the posterior distribution for a high-dimensional parameter, where we impose
sparsity in the precision matrix to reflect appropriate conditional
independence structure in the model. Incorporating sparsity in the precision
matrix allows the Gaussian variational distribution to be both flexible and
parsimonious, and the sparsity is achieved through parameterization in terms of
the Cholesky factor. Efficient stochastic gradient methods which make
appropriate use of gradient information for the target distribution are
developed for the optimization. We consider alternative estimators of the
stochastic gradients which have lower variation and are more stable. Our
approach is illustrated using generalized linear mixed models and state space
models for time series.


title:
Structure formation simulations with momentum exchange: alleviating
  tensions between high-redshift and low-redshift cosmological probes

abstract:
  Persisting tensions between the cosmological constraints derived from
low-redshift probes and the ones obtained from temperature and polarisation
anisotropies of the Cosmic Microwave Background -- although not yet providing
compelling evidence against the $\Lambda $CDM model -- seem to consistently
indicate a slower growth of density perturbations as compared to the
predictions of the standard cosmological scenario. Such behavior is not easily
accommodated by the simplest extensions of General Relativity, such as f(R)
models, which generically predict an enhanced growth rate. In the present work
we present the outcomes of a suite of large N-body simulations carried out in
the context of a cosmological model featuring a non-vanishing scattering cross
section between the dark matter and the dark energy fields, for two different
parameterisations of the dark energy equation of state. Our results indicate
that these Dark Scattering models have very mild effects on many observables
related to large-scale structures formation and evolution, while providing a
significant suppression of the amplitude of linear density perturbations and
the abundance of massive clusters. Our simulations therefore confirm that these
models offer a promising route to alleviate existing tensions between
low-redshift measurements and those of the CMB.


title:
Brownian regime of finite-N corrections to particle motion in the XY
  hamiltonian mean field model

abstract:
  We study the dynamics of the N-particle system evolving in the XY hamiltonian
mean field (HMF) model for a repulsive potential, when no phase transition
occurs. Starting from a homogeneous distribution, particles evolve in a mean
field created by the interaction with all others. This interaction does not
change the homogeneous state of the system, and particle motion is
approximately ballistic with small corrections. For initial particle data
approaching a waterbag, it is explicitly proved that corrections to the
ballistic velocities are in the form of independent brownian noises over a time
scale diverging not slower than $N^{2/5}$ as $N \to \infty$, which proves the
propagation of molecular chaos. Molecular dynamics simulations of the XY-HMF
model confirm our analytical findings.

categories: cond-mat.stat-mech math-ph math.MP nlin.CD physics.plasm-ph


title:
Hybrid Level Aspect Subconvexity for $GL(2)\times GL(1)$ Rankin-Selberg
  $L$-Functions

abstract:
  Let $M$ be a squarefree positive integer and $P$ a prime number coprime to
$M$ such that $P\sim M^\eta$ with $0 < \eta < 2/5$. We simplify the proof of
subconvexity bounds for $L(\frac{1}{2},f\otimes\chi)$ when $f$ is a primitive
holomorphic cusp form of level $P$ and $\chi$ is a primitive Dirichlet
character modulo $M$. These bounds are attained through an unamplified second
moment method using a modified version of the delta method due to R. Munshi.
The technique is similar to that used by Duke-Friedlander-Iwaniec save for the
modification of the delta method.


title: New classes of matrix decompositions

abstract:
  The idea of decomposing a matrix into a product of structured matrices such
as triangular, orthogonal, diagonal matrices is a milestone of numerical
computations. In this paper, we describe six new classes of matrix
decompositions, extending our work in arXiv:1307.5132. We prove that every
$n\times n$ matrix is a product of finitely many bidiagonal, skew symmetric
(when n is even), generic, companion matrices and generalized Vandermonde
matrices, respectively. We also prove that a generic $n\times n$
centrosymmetric matrix is a product of finitely many symmetric Toeplitz (resp.
persymmetric Hankel) matrices. We determine an upper bound of the number of
structured matrices needed to decompose a matrix for each case.


title: The 750 GeV excess from photon-photon and quark-quark processes

abstract:
  The observed excess in the diphoton mass spectrum around 750 GeV at the 13
TeV LHC possibly indicates the presence of a photonphilic resonance. We show
that the excess can be explained by a scalar of the type involved in
Bekenstein's framework for varying electromagnetic coupling theories. The
scalar, in our model, couples dominantly to photons and is mainly produced by
the quark-quark fusion at the LHC. In addition, it can also be produced in
photon-photon fusion. Our model has only two free parameters, the mass of the
scalar and the scale of the new physics, which are fixed by the LHC excess to
750 GeV and 1.5 - 2 TeV, respectively. The scalar has a large three-body decay
to a fermion pair and a photon, which provides an interesting search channel
with a dilepton-photon resonance around 750 GeV.