title: Deep CORAL: Correlation Alignment for Deep Domain Adaptation

abstract:
  Deep neural networks are able to learn powerful representations from large
quantities of labeled input data, however they cannot always generalize well
across changes in input distributions. Domain adaptation algorithms have been
proposed to compensate for the degradation in performance due to domain shift.
In this paper, we address the case when the target domain is unlabeled,
requiring unsupervised adaptation. CORAL is a "frustratingly easy" unsupervised
domain adaptation method that aligns the second-order statistics of the source
and target distributions with a linear transformation. Here, we extend CORAL to
learn a nonlinear transformation that aligns correlations of layer activations
in deep neural networks (Deep CORAL). Experiments on standard benchmark
datasets show state-of-the-art performance.


title: Approximation of the potential in scalar field dark energy models

abstract:
  We study the nature of potentials in scalar field based models for dark
energy - with both canonical and noncanonical kinetic terms. We calculate
numerically, and using an analytic approximation around $a\approx 1$,
potentials for models with constant equation-of-state parameter, $w_{\phi}$. We
find that for a wide range of models with canonical and noncanonical kinetic
terms there is a simple approximation for the potential that holds when the
scale factor is in the range $0.6\lesssim a\lesssim 1.4$. We discuss how this
form of the potential can also be used to represent models with non-constant
$w_{\phi}$ and, hence, how it could be used in reconstruction from cosmological
data.


title:
Instability of Static Semi-Closed Worlds in Generalized Galileon
  Theories

abstract:
  We consider generalized Galileon theories within general relativity in
four-dimensional space-time. We provide the argument showing that the
generalized Galileons described by a wide class of Lagrangians do not admit
stable, static, spherically symmetric semi-closed worlds. We also show that in
a class of theories with $p_{\perp} = - \rho$ (where $p_{\perp}$ is transverse
pressure and $\rho$ is energy density), semi-closed worlds, if exist, would be
observed as objects of negative mass.


title: Cochran's $\beta^i$ invariants via twisted Whitney towers

abstract:
  We show that Tim Cochran's invariants $\beta^i(L)$ of a $2$-component link
$L$ in the $3$--sphere can be computed as intersection invariants of certain
2-complexes in the $4$--ball with boundary $L$. These 2-complexes are special
types of twisted Whitney towers, which we call {\em Cochran towers}, and which
exhibit a new phenomenon: A Cochran tower of order $2k$ allows the computation
of the $\beta^i$ invariants for all $i\leq k$, i.e. simultaneous extraction of
invariants from a Whitney tower at multiple orders. This is in contrast with
the order $n$ Milnor invariants (requiring order $n$ Whitney towers) and
consistent with Cochran's result that the $\beta^i(L)$ are integer lifts of
certain Milnor invariants.


title: GUICop: Approach and Toolset for Specification-based GUI Testing

abstract:
  Oracles used for testing graphical user interface (GUI) programs are required
to take into consideration complicating factors such as variations in screen
resolution or color scheme when comparing observed GUI elements to expected GUI
elements. Researchers proposed fuzzy comparison rules and computationally
expensive image processing techniques to tame the comparison process since
otherwise the naive matching comparison would be too constraining and
consequently impractical. Alternatively, this paper proposes GUICop, a novel
approach with a supporting toolset that takes (1) a GUI program and (2)
user-defined GUI specifications characterizing the rendering behavior of the
GUI elements, and checks whether the execution traces of the program satisfy
the specifications. GUICop comprises the following: 1) a GUI Specification
Language; 2) a Driver; 3) Instrumented GUI Libraries; 4) a Solver; and 5) a
Code Weaver. The user defines the specifications of the subject GUI program
using the GUI Specification Language. The Driver traverses the GUI structure of
the program and generates events that drive its execution. The Instrumented GUI
Libraries capture the GUI execution trace, i.e., information about the
positions and visibility of the GUI elements. And the Solver, enabled by code
injected by the Code Weaver, checks whether the traces satisfy the
specifications. GUICop was successfully evaluated using four open source GUI
applications that included eight defects, namely, Jajuk, Gason, JEdit, and
TerpPaint.


title: Cyclic noncommutative covering projections

abstract:
  The Gelfand - Na\u{i}mark theorem supplies the one to one correspondence
between commutative $C^*$-algebras and locally compact Hausdorff spaces. So any
noncommutative $C^*$-algebra can be regarded as a generalization of a
topological space. Generalizations of several topological invariants can be
defined by algebraical methods. This article contains a pure algebraical
construction of (noncommutative) covering projections with finite cyclic groups
of covering transformations.


title: Smooth surjections and surjective restrictions

abstract:
  Given a surjective mapping $f : E \to F$ between Banach spaces, we
investigate the existence of a subspace $G$ of $E$, with the same density
character as $F$, such that the restriction of $f$ to $G$ remains surjective.
We obtain a positive answer whenever $f$ is continuous and uniformly open. In
the smooth case, we deduce a positive answer when $f$ is a $C^1$-smooth
surjection whose set of critical values is countable. Finally we show that,
when $f$ takes values in the Euclidean space $\mathbb R^n$, in order to obtain
this result it is not sufficient to assume that the set of critical values of
$f$ has zero-measure.


title:
Numerical Analysis for a System Coupling Curve Evolution to
  Reaction-Diffusion on the Curve

abstract:
  We consider a finite element approximation for a system consisting of the
evolution of a closed planar curve by forced curve shortening flow coupled to a
reaction-diffusion equation on the evolving curve. The scheme for the curve
evolution is based on a parametric description allowing for tangential motion,
whereas the discretisation for the PDE on the curve uses an idea from [6]. We
prove optimal error bounds for the resulting fully discrete approximation and
present numerical experiments. These confirm our estimates and also illustrate
the advantage of the tangential motion of the mesh points in practice.


title:
Eigenvalue bounds for non-self-adjoint Schr\"odinger operators with the
  inverse-square potential

abstract:
  The purpose of this paper is to study spectral properties of non-self-adjoint
Schr\"odinger operators $-\Delta-\frac{(n-2)^2}{4|x|^{2}}+V$ on $\mathbb{R}^n$
with complex-valued potentials $V\in L^{p,\infty}$, $p>n/2$. We prove Keller
type inequalities which measure the radius of a disc containing the discrete
spectrum, in terms of the $L^{p,\infty}$ norm of $V$. Similar inequalities also
hold if the inverse-square potential is replaced by a large class of
subcritical potentials with critical singularities at the origin. The main new
ingredient in the proof is the uniform Sobolev inequality of Kenig-Ruiz-Sogge
type for Schr\"odinger operators with strongly singular potentials, which is of
independent interest.


title:
Embedding Assignment Routing Constraints through Multi Dimensional
  Network Construction for Solving the Multi Vehicle Routing Problem with
  Pickup and Delivery with Time Windows

abstract:
  The multi Vehicle Routing Problem with Pickup and Delivery with Time Windows
is a challenging version of the Vehicle Routing Problem. In this paper, by
embedding many complex assignment routing constraints through constructing a
multi dimensional network, we intend to reach optimality for local clusters
derived from a reasonably large set of passengers on real world transportation
networks. More specifically, we introduce a multi vehicle state space time
network representation in which only the non dominated assignment based hyper
paths are examined. In addition, by the aid of passengers cumulative service
patterns defined in this paper, our solution approach is able to take control
of symmetry issue, a common issue in the combinatorial problems. At the end,
extensive computational results over the instances proposed by Ropke and
Cordeau 2009 and a randomly generated data sets from the Phoenix subarea, City
of Tempe, show the computational efficiency and solution optimality of our
developed algorithm.


title: Cost-Optimal Algorithms for Planning with Procedural Control Knowledge

abstract:
  There is an impressive body of work on developing heuristics and other
reasoning algorithms to guide search in optimal and anytime planning algorithms
for classical planning. However, very little effort has been directed towards
developing analogous techniques to guide search towards high-quality solutions
in hierarchical planning formalisms like HTN planning, which allows using
additional domain-specific procedural control knowledge. In lieu of such
techniques, this control knowledge often needs to provide the necessary search
guidance to the planning algorithm, which imposes a substantial burden on the
domain author and can yield brittle or error-prone domain models. We address
this gap by extending recent work on a new hierarchical goal-based planning
formalism called Hierarchical Goal Network (HGN) Planning to develop the
Hierarchically-Optimal Goal Decomposition Planner (HOpGDP), an HGN planning
algorithm that computes hierarchically-optimal plans. HOpGDP is guided by
$h_{HL}$, a new HGN planning heuristic that extends existing admissible
landmark-based heuristics from classical planning to compute admissible cost
estimates for HGN planning problems. Our experimental evaluation across three
benchmark planning domains shows that HOpGDP compares favorably to both optimal
classical planners due to its ability to use domain-specific procedural
knowledge, and a blind-search version of HOpGDP due to the search guidance
provided by $h_{HL}$.


title: Rolling Horizon Coevolutionary Planning for Two-Player Video Games

abstract:
  This paper describes a new algorithm for decision making in two-player
real-time video games. As with Monte Carlo Tree Search, the algorithm can be
used without heuristics and has been developed for use in general video game
AI. The approach is to extend recent work on rolling horizon evolutionary
planning, which has been shown to work well for single-player games, to two (or
in principle many) player games. To select an action the algorithm co-evolves
two (or in the general case N) populations, one for each player, where each
individual is a sequence of actions for the respective player. The fitness of
each individual is evaluated by playing it against a selection of
action-sequences from the opposing population. When choosing an action to take
in the game, the first action is chosen from the fittest member of the
population for that player. The new algorithm is compared with a number of
general video game AI algorithms on three variations of a two-player space
battle game, with promising results.


title: On the Atomic Structure of Puiseux Monoids

abstract:
  In this paper, we study the atomic structure of the family of Puiseux
monoids. Puiseux monoids are a natural generalization of numerical semigroups,
which have been actively studied since mid-nineteenth century. Unlike numerical
semigroups, the family of Puiseux monoids contains non-finitely generated
representatives. Even more interesting is that there are many Puiseux monoids
which are not even atomic. We delve into these situations, describing, in
particular, a vast collection of commutative cancellative monoids containing no
atoms. On the other hand, we find several characterization criteria which force
Puiseux monoids to be atomic. Finally, we classify the atomic subfamily of
strongly bounded Puiseux monoids over a finite set of primes.


title:
Hydrodynamic flow amplitude correlations in event-by-event fluctuating
  heavy-ion collisions

abstract:
  The effects of event-by-event fluctuations in the initial geometry of the
colliding nuclei are important in the analysis of final flow observables in
relativistic heavy-ion collisions. We use hydrodynamic simulations to study the
amplitude correlations between different orders of event-by-event fluctuating
anisotropic flow harmonics. While the general trends seen in the experimental
data are qualitatively reproduced by the model, deviations in detail, in
particular for peripheral collisions, point to the need for more elaborate
future calculations with a hybrid approach that describes the late hadronic
stage of the evolution microscopically. It is demonstrated explicitly that the
observed anti-correlation between $v_2$ and $v_3$ is the consequence of
approximately linear hydrodynamic response to a similar anti-correlation of the
corresponding initial eccentricities $\epsilon_2$ and $\epsilon_3$. For
$n{\,>\,}3$, the hydrodynamic correlations between $v_{2,3}$ and $v_n$ deviate
from the rescaled correlations among the corresponding initial eccentricities,
demonstrating nonlinear mode coupling effect in higher order flows.


title: Fast computation of the matrix exponential for a Toeplitz matrix

abstract:
  The computation of the matrix exponential is a ubiquitous operation in
numerical mathematics, and for a general, unstructured $n\times n$ matrix it
can be computed in $\mathcal{O}(n^3)$ operations. An interesting problem arises
if the input matrix is a Toeplitz matrix, for example as the result of
discretizing integral equations with a time invariant kernel. In this case it
is not obvious how to take advantage of the Toeplitz structure, as the
exponential of a Toeplitz matrix is, in general, not a Toeplitz matrix itself.
The main contribution of this work are fast algorithms for the computation of
the Toeplitz matrix exponential. The algorithms have provable quadratic
complexity if the spectrum is real, or sectorial, or more generally, if the
imaginary parts of the rightmost eigenvalues do not vary too much. They may be
efficient even outside these spectral constraints. They are based on the
scaling and squaring framework, and their analysis connects classical results
from rational approximation theory to matrices of low displacement rank. As an
example, the developed methods are applied to Merton's jump-diffusion model for
option pricing.


title:
Discontinuous fluidisation transition in assemblies of
  actively-deforming particles: A new paradigm for collective motion in dense
  active materials

abstract:
  Tracking experiments in dense biological tissues reveal a diversity of
sources f or local energy injection at the cell scale. The effect of cell
motility has been largely studied, but much less is known abo ut the effect of
the observed volume fluctuations of individual cells. We devise a simple
microscopic model of `actively-deforming' particles where local fluctuations of
the particle size constitute a unique source of motion. We demonstrate that
collective motion can emerge under the sole influence of such active volume
fluctuations. We interpret the onset of diffusive motion as a nonequilibrium
first-order phase transition, which arises at a well-defined amplitude of
self-deformation. This behaviour contrasts with the glassy dynamics produced by
self-propulsion, but resembles the mechanical response of soft solids under
mechanical deformation. It thus constitutes the first example of active
yielding transition.


title:
A maximum entropy approach to separating noise from signal in bimodal
  affiliation networks

abstract:
  In practice, many empirical networks, including co-authorship and collocation
networks are unimodal projections of a bipartite data structure where one layer
represents entities, the second layer consists of a number of sets representing
affiliations, attributes, groups, etc., and an inter-layer link indicates
membership of an entity in a set. The edge weight in the unimodal projection,
which we refer to as a co-occurrence network, counts the number of sets to
which both end-nodes are linked. Interpreting such dense networks requires
statistical analysis that takes into account the bipartite structure of the
underlying data. Here we develop a statistical significance metric for such
networks based on a maximum entropy null model which preserves both the
frequency sequence of the individuals/entities and the size sequence of the
sets. Solving the maximum entropy problem is reduced to solving a system of
nonlinear equations for which fast algorithms exist, thus eliminating the need
for expensive Monte-Carlo sampling techniques. We use this metric to prune and
visualize a number of empirical networks.


title: On Achievability of an $(r,l)$ Fractional Linear Network Code

abstract:
  It is known that there exists a network, called as the M-network, which is
not scalar linearly solvable but has a vector linear solution for message
dimension two. Recently, a generalization of this result has been presented
where it has been shown that for any integer $m\geq 2$, there exists a network
which has a $(m,m)$ vector linear solution, but does not have a $(w,w)$ vector
linear solution for $w<m$. This paper presents a further generalization.
Specifically, we show that for any positive integers $k,n,$ and $m\geq 2$,
there exists a network which has a $(mk,mn)$ fractional linear solution, but
does not have a $(wk,wn)$ fractional linear solution for $w<m$.


title:
Quasi-Periodicities in the Anomalous Emission Events in Pulsars B1859+07
  and B0919+06

abstract:
  A quasi-periodicity has been identified in the strange emission shifts in
pulsar B1859+07 and possibly B0919+06. These events, first investigated by
Rankin, Rodriguez & Wright in 2006, originally appeared disordered or random,
but further mapping as well as Fourier analysis has revealed that they occur on
a fairly regular basis of approximately 150 rotation periods in B1859+07 and
perhaps some 700 in B0919+06. The events-which we now refer to as
"swooshes"-are not the result of any known type of mode-changing, but rather we
find that they are a uniquely different effect, produced by some mechanism
other than any known pulse-modulation phenomenon. Given that we have yet to
find another explanation for the swooshes, we have appealed to a last resort
for periodicities in astrophysics: orbital dynamics in a binary system. Such
putative "companions" would then have semi-major axes comparable to the light
cylinder radius for both pulsars. However, in order to resist tidal disruption
their densities must be at least some 10$^5$ grams/cm$^3$-therefore white-dwarf
cores or something even denser might be indicated.


title:
Measuring Collisionless Damping in Heliospheric Plasmas using
  Field-Particle Correlations

abstract:
  An innovative field-particle correlation technique is proposed that uses
single-point measurements of the electromagnetic fields and particle velocity
distribution functions to investigate the net transfer of energy from fields to
particles associated with the collisionless damping of turbulent fluctuations
in weakly collisional plasmas, such as the solar wind. In addition to providing
a direct estimate of the local rate of energy transfer between fields and
particles, it provides vital new information about the distribution of that
energy transfer in velocity space. This velocity-space signature can
potentially be used to identify the dominant collisionless mechanism
responsible for the damping of turbulent fluctuations in the solar wind. The
application of this novel field-particle correlation technique is illustrated
using the simplified case of the Landau damping of Langmuir waves in an
electrostatic 1D-1V Vlasov-Poisson plasma, showing that the procedure both
estimates the local rate of energy transfer from the electrostatic field to the
electrons and indicates the resonant nature of this interaction. Modifications
of the technique to enable single-point spacecraft measurements of fields and
particles to diagnose the collisionless damping of turbulent fluctuations in
the solar wind are discussed, yielding a method with the potential to transform
our ability to maximize the scientific return from current and upcoming
spacecraft missions, such as the Magnetospheric Multiscale (MMS) and Solar
Probe Plus missions.


title:
Cohomologie non ramifi\'ee de degr\'e 3 : vari\'et\'es cellulaires et
  surfaces de del Pezzo de degr\'e au moins 5

abstract:
  We consider geometrically cellular varieties $X$ over an arbitrary field of
characteristic zero. We study the quotient of the third unramified cohomology
group $H^3_{nr}(X,\mathbb{Q}/\mathbb{Z}(2))$ by its constant part. For $X$ a
smooth compactification of a universal torsor over a geometrically rational
surface, we show that this quotient if finite. For $X$ a del Pezzo surface of
degree $\geq 5$, we show that this quotient is zero, unless $X$ is a del Pezzo
surface of degree 8 of a special type.


title: Belle II early physics program of bottomonium spectroscopy

abstract:
  The Belle II experiment at the SuperKEKB collider is a major upgrade of the
KEK "$B$ factory" facility in Tsukuba, Japan. Phase 1 commissioning of the main
ring of SuperKEKB has started in February 2016 and first physics data will be
recorded in 2017 during the so-called Phase 2 commissioning, when the partial
Belle II detector will be operated still without its vertex detector. In 2018,
the full Belle II detector will be rolled in and physics run will start. In
this proceeding, a possible physics program for this early data run at
different center-of-mass energies is described, in particular at the
$\Upsilon(3S)$ and $\Upsilon(6S)$ resonances, amongst other energy points.


title: A note on properties of the restriction operator on Sobolev spaces

abstract:
  In our companion paper (S.N. Chandler Wilde, D.P. Hewett, A. Moiola, Sobolev
spaces on non-Lipschitz subsets of $\mathbb{R}^n$ with application to boundary
integral equations on fractal screens, 2016) we studied a number of different
Sobolev spaces on a general (non-Lipschitz) open subset $\Omega$ of
$\mathbb{R}^n$, defined as closed subspaces of the classical Bessel potential
spaces $H^s(\mathbb{R}^n)$ for $s\in\mathbb{R}$. These spaces are mapped by the
restriction operator to certain spaces of distributions on $\Omega$. In this
note we make some observations about the relation between these spaces of
global and local distributions. In particular, we study conditions under which
the restriction operator is or is not injective, surjective and isometric
between given pairs of spaces. We also provide an explicit formula for minimal
norm extension (an inverse of the restriction operator in appropriate spaces)
in a special case.


title:
Generating maximally disassortative graphs with given degree
  distribution

abstract:
  In this paper we consider the optimization problem of generating graphs with
a prescribed degree distribution, such that the correlation between the degrees
of connected nodes, as measured by Spearman's rho, is minimal. We provide an
algorithm for solving this problem and obtain a complete characterization of
the joint degree distribution in these maximally disassortative graphs, in
terms of the size-biased degree distribution. As a result we get a lower bound
for Spearman's rho on graphs with an arbitrary given degree distribution. We
use this lower bound to show that for any fixed tail exponent, there exist
scale-free degree sequences with this exponent such that the minimum value of
Spearman's rho for all graphs with such degree sequences is arbitrary close to
zero. This implies that specifying only the tail behavior of the degree
distribution, as is often done in the analysis of complex networks, gives no
guarantees for the minimum value of Spearman's rho.


title: BPS states in the Minahan-Nemeschansky E6 theory

abstract:
  We use the method of spectral networks to compute BPS state degeneracies in
the Minahan-Nemeschansky $E_6$ theory, on its Coulomb branch, without turning
on a mass deformation. The BPS multiplicities come out in representations of
the $E_6$ flavor symmetry. For example, along the simplest ray in
electromagnetic charge space, we give the first $14$ numerical degeneracies,
and the first $7$ degeneracies as representations of $E_6$. We find a
complicated spectrum, exhibiting exponential growth of multiplicities as a
function of the electromagnetic charge. There is one unexpected outcome: the
spectrum is consistent (in a nontrivial way) with the hypothesis of "spin
purity," that if a BPS state in this theory has electromagnetic charge equal to
$n$ times a primitive charge, then it appears in a spin-$\frac{n}{2}$
multiplet.


title:
Diffusion Approximations for Double-ended Queues with Reneging in Heavy
  Traffic

abstract:
  We study a double-ended queue which consists of two classes of customers.
Whenever there is a pair of customers from both classes, they are matched and
leave the system immediately. The matching follows first-come-first-serve
principle. If a customer from one class cannot be matched immediately, he/she
will stay in a queue and wait for the upcoming arrivals from the other class.
Thus there cannot be non-zero numbers of customers from both classes
simultaneously in the system. We also assume that each customer can leave the
queue without being matched because of impatience. The arrival processes are
assumed to be independent renewal processes, and the patience times for both
classes are generally distributed. Under suitable heavy traffic conditions,
assuming that the diffusion-scaled queue length process is stochastically
bounded, we establish a simple asymptotic relationship between the
diffusion-scaled queue length process and the diffusion-scaled offered waiting
time process, and further show that the diffusion-scaled queue length process
converges weakly to a diffusion process. We also provide a sufficient condition
for the stochastic boundedness of the diffusion-scaled queue length process. At
last, the explicit form of the stationary distribution of the limit diffusion
process is derived.


title:
Degeneracy between $\theta_{23}$ octant and neutrino non-standard
  interactions at DUNE

abstract:
  We expound in detail the degeneracy between the octant of $\theta_{23}$ and
flavor-changing neutral-current non-standard interactions (NSI's) in neutrino
propagation, considering the Deep Underground Neutrino Experiment (DUNE) as a
case study. In the presence of such NSI parameters involving the $e-\mu$
($\varepsilon_{e\mu}$) and $e-\tau$ ($\varepsilon_{e\tau}$) flavors, the
$\nu_\mu \to \nu_e$ and $\bar\nu_\mu \to \bar\nu_e$ appearance probabilities in
long-baseline experiments acquire an additional interference term, which
depends on one new dynamical CP-phase $\phi_{e\mu/e\tau}$. This term sums up
with the well-known interference term related to the standard CP-phase $\delta$
creating a source of confusion in the determination of the octant of
$\theta_{23}$. We show that for values of the NSI coupling (taken one
at-a-time) as small as $few\,\%$ (relative to the Fermi coupling constant
$G_{\mathrm F}$), and for unfavorable combinations of the two CP-phases
$\delta$ and $\phi_{e\mu/e\tau}$, the discovery potential of the octant of
$\theta_{23}$ gets completely lost.


title: Using Perturbations to Probe the Neural Control of Rhythmic Movements

abstract:
  Small continuous sensory and mechanical perturbations have often been used to
identify properties of the closed-loop neural control of posture and other
systems that are approximately linear time invariant. Here we extend this
approach to study the neural control of rhythmic behaviors such as walking. Our
method is based on the theory of linear time periodic systems, with
modifications to account for ability of perturbations to reset the phase of a
rhythmic behavior. We characterize responses to perturbations in the frequency
domain using harmonic transfer functions and then convert to the time domain to
obtain phase-dependent impulse response functions (IRFs) that describe the
response to a small brief perturbation at any phase of the rhythmic behavior.
IRFs describing responses of kinematic variables and muscle activations
(measured by EMG) to sensory and mechanical perturbations can be used to infer
properties of the plant, the mapping from muscle activation to movement, and of
neural feedback, the mapping from movement to muscle activation. We illustrate
our method by applying it to simulated data from a model and experimental data
of subjects walking on a treadmill perturbed by movement of the visual scene.


title: On Brane Instabilities in the Large $D$ Limit

abstract:
  Using an expansion in large number of dimensions, taken to subleading orders,
we discuss several issues concerning the Gregory-Laflamme instabilities. We map
out the phase diagram of neutral and charged black strings, and comment on the
possible transition in the nature of the final state of the instability at
higher order in the 1/D expansion. We also discuss unstable black membranes,
and show that in certain limits the preferred shape of the non-uniform phase is
a triangular lattice.


title:
Equivariant classification of $b^m$-symplectic surfaces and Nambu
  structures

abstract:
  In this paper we extend the classification scheme in [S] for $b^m$-symplectic
surfaces and, more generally, $b^m$-Nambu structures to the equivariant
setting. When the compact group is the group of deck-transformations of an
orientable covering, this yields the classification of these objects for
non-orientable surfaces. The paper also includes recipes to construct
$b^m$-symplectic structures on surfaces. Feasibility of such constructions
depends on orientability and on the colorability of an associated graph. The
desingularization technique in [GMW] is revisited for surfaces and the
compatibility with this classification scheme is analyzed. We recast the
strategy used in [Mt] to classify stable Nambu structures of top degree on
orientable manifolds to classify $b^m$-Nambu structures (not necessarily
oriented) using the language of $b^m$-cohomology. The paper ends up with an
equivariant classification theorem of $b^m$-Nambu structures of top degree.


title: Z+jet production at NNLO

abstract:
  We give a brief overview of our calculation of the next-to-next-to-leading
order (NNLO) QCD corrections to Z+jet production in hadronic collisions.
Phenomenological results are presented which comprise various differential
distributions for 8 TeV proton-proton collisions. A significant reduction of
the scale uncertainties is observed throughout as we move from NLO to NNLO. We
further discuss how this calculation can be used to describe the inclusive
Z-boson production at large transverse momentum. To this end, the theory
prediction is compared to the measurements performed by the ATLAS and CMS
collaborations at a centre-of-mass energy of 8 TeV. Here, the inclusion of NNLO
QCD effects are found to result in a substantial improvement in the agreement
between theory and data for the normalised distributions.


title:
Formal Definitions of Unbounded Evolution and Innovation Reveal
  Universal Mechanisms for Open-Ended Evolution in Dynamical Systems

abstract:
  Open-ended evolution (OEE) is relevant to a variety of biological, artificial
and technological systems, but has been challenging to reproduce in silico.
Most theoretical efforts focus on key aspects of open-ended evolution as it
appears in biology. We recast the problem as a more general one in dynamical
systems theory, providing simple criteria for open-ended evolution based on two
hallmark features: unbounded evolution and innovation. We define unbounded
evolution as patterns that are non-repeating within the expected Poincare
recurrence time of an equivalent isolated system, and innovation as
trajectories not observed in isolated systems. As a case study, we implement
novel variants of cellular automata (CA) in which the update rules are allowed
to vary with time in three alternative ways. Each is capable of generating
conditions for open-ended evolution, but vary in their ability to do so. We
find that state-dependent dynamics, widely regarded as a hallmark of life,
statistically out-performs other candidate mechanisms, and is the only
mechanism to produce open-ended evolution in a scalable manner, essential to
the notion of ongoing evolution. This analysis suggests a new framework for
unifying mechanisms for generating OEE with features distinctive to life and
its artifacts, with broad applicability to biological and artificial systems.


title:
Derivative pricing as a transport problem: MPDATA solutions to
  Black-Scholes-type equations

abstract:
  We discuss in this note applications of the Multidimensional Positive
Definite Advection Transport Algorithm (MPDATA) to numerical solutions of
partial differential equations arising from stochastic models in quantitative
finance. In particular, we develop a framework for solving Black-Scholes-type
equations by first transforming them into advection-diffusion problems, and
numerically integrating using an iterative explicit finite-difference approach,
in which the Fickian term is represented as an additional advective term. We
discuss the correspondence between transport phenomena and financial models,
uncovering the possibility of expressing the no-arbitrage principle as a
conservation law. We depict second-order accuracy in time and space of the
embraced numerical scheme. This is done in a convergence analysis comparing
MPDATA numerical solutions with classic Black-Scholes analytical formulae for
the valuation of European options. We demonstrate in addition a way of applying
MPDATA to solve the free boundary problem (leading to a linear complementarity
problem) for the valuation of American options. We finally comment on the
potential the MPDATA framework has with respect to being applied in tandem with
more complex models typically used in quantitive finance.


title: CrowdCafe - Mobile Crowdsourcing Platform

abstract:
  In this paper we present a mobile crowdsourcing platform CrowdCafe, where
people can perform microtasks using their smartphones while they ride a bus,
travel by train, stand in a queue or wait for an appointment. These microtasks
are executed in exchange for rewards provided by local stores, such as coffee,
desserts and bus tickets. We present the concept, the implementation and the
evaluation by conducting a study with 52 participants, having 1108 tasks
completed.


title: Symmetries and Couplings of Non-Relativistic Electrodynamics

abstract:
  We examine three versions of non-relativistic electrodynamics, known as the
electric and magnetic limit theories of Maxwell's equations and Galilean
electrodynamics (GED) which is the off-shell non-relativistic limit of Maxwell
plus a free scalar field. For each of these three cases we study the couplings
to non-relativistic dynamical charged matter (point particles and charged
complex scalars). The GED theory contains besides the electric and magnetic
potentials a so-called mass potential making the mass parameter a local
function. The electric and magnetic limit theories can be coupled to twistless
torsional Newton-Cartan geometry while GED can be coupled to an arbitrary
torsional Newton-Cartan background. The global symmetries of the electric and
magnetic limit theories on flat space consist in any dimension of the infinite
dimensional Galilean conformal algebra and a $U(1)$ current algebra. For the
on-shell GED theory this symmetry is reduced but still infinite dimensional,
while off-shell only the Galilei algebra plus two dilatations remain. Hence one
can scale time and space independently, allowing Lifshitz scale symmetries for
any value of the critical exponent $z$.


title: Optimal counter-current exchange networks

abstract:
  We present a general analysis of exchange devices linking their efficiency to
the geometry of the exchange surface and supply network. For certain parameter
ranges, we show that the optimal exchanger consists of densely packed pipes
which can span a thin sheet of large area (an `active layer'), which may be
crumpled into a fractal surface and supplied with a fractal network of pipes.
We derive the efficiencies of such exchangers, showing the potential for
significant gains compared to regular exchangers (where the active layer is
flat), using parameters relevant for biological systems.


title:
KELT-11b: A Highly Inflated Sub-Saturn Exoplanet Transiting the V=8
  Subgiant HD 93396

abstract:
  We report the discovery of a transiting exoplanet, KELT-11b, orbiting the
bright ($V=8.0$) subgiant HD 93396. A global analysis of the system shows that
the host star is an evolved subgiant star with $T_{\rm eff} = 5370\pm51$ K,
$M_{*} = 1.438_{-0.052}^{+0.061} M_{\odot}$, $R_{*} = 2.72_{-0.17}^{+0.21}
R_{\odot}$, log $g_*= 3.727_{-0.046}^{+0.040}$, and [Fe/H]$ = 0.180\pm0.075$.
The planet is a low-mass gas giant in a $P = 4.736529\pm0.00006$ day orbit,
with $M_{P} = 0.195\pm0.018 M_J$, $R_{P}= 1.37_{-0.12}^{+0.15} R_J$, $\rho_{P}
= 0.093_{-0.024}^{+0.028}$ g cm$^{-3}$, surface gravity log ${g_{P}} =
2.407_{-0.086}^{+0.080}$, and equilibrium temperature $T_{eq} =
1712_{-46}^{+51}$ K. KELT-11 is the brightest known transiting exoplanet host
in the southern hemisphere by more than a magnitude, and is the 6th brightest
transit host to date. The planet is one of the most inflated planets known,
with an exceptionally large atmospheric scale height (2763 km), and an
associated size of the expected atmospheric transmission signal of 5.6%. These
attributes make the KELT-11 system a valuable target for follow-up and
atmospheric characterization, and it promises to become one of the benchmark
systems for the study of inflated exoplanets.


title:
Protocol for an Observational Study on the Effects of Playing High
  School Football on Later Life Cognitive Functioning and Mental Health

abstract:
  A potential causal relationship between head injuries sustained by NFL
players and later-life neurological decline may have broad implications for
participants in youth and high school football programs. However, brain trauma
risk at the professional level may be different than that at the youth and high
school levels and the long-term effects of participation at these levels is
as-yet unclear. To investigate the effect of playing high school football on
later life depression and cognitive functioning, we propose a retrospective
observational study using data from the Wisconsin Longitudinal Study (WLS) of
graduates from Wisconsin high schools in 1957.
  We compare 1,153 high school males who played varsity football to 2,751 male
students who did not. 1,951 of the control subjects did not play any sport and
the remaining 800 controls played a non-contact sport. We focus on two primary
outcomes measured at age 65: a composite cognitive outcome measuring verbal
fluency and memory and the modified CES-D depression score. To control for
potential confounders we adjust for pre-exposure covariates such as IQ with
matching and model-based covariate adjustment. We will conduct an ordered
testing procedure that uses all 2,751 controls while controlling for possible
unmeasured differences between students who played sports and those who did
not. We will quantitatively assess the sensitivity of the results to potential
unmeasured confounding. The study will also consider several secondary outcomes
of clinical interest such as aggression and heavy drinking. The rich set of
pre-exposure variables, relatively unbiased sampling, and longitudinal nature
of the WLS dataset make the proposed analysis unique among related studies that
rely primarily on convenience samples of football players with reported
neurological symptoms.


title:
Circular Photogalvanic Effect in Organometal Halide Perovskite
  CH$_3$NH$_3$PbI$_3$

abstract:
  We study the circular photogalvanic effect in the organometal halide
perovskite solar cell absorber CH$_3$NH$_3$PbI$_3$. For crystal structures
which lack inversion symmetry, the calculated photocurrent density is about
$10^{-9}$ A/W, comparable to the previously studied quantum well and bulk
Rashba systems. Because of the dependence of the circular photogalvanic effect
on inversion symmetry breaking, the degree of inversion asymmetry at different
depths from the surface can be probed by tuning the photon energy and
associated penetration depth. We propose that measurements of this effect may
clarify the presence or absence of inversion symmetry, which remains a
controversial issue and has been argued to play an important role in the high
conversion efficiency of this material.


title: A Localized Besicovitch-Federer Projection Theorem

abstract:
  The classical Besicovitch-Federer projection theorem implies that the
d-dimensional Hausdorff measure of a set in Euclidean space with non-negligible
d-unrectifiable part will strictly decrease under orthogonal projection onto
almost every d-dimensional linear subspace. In fact, there exist maps which are
arbitrarily close to the identity in the C^0 topology which have the same
property. A converse holds as well, yielding the following rectifiability
criterion: under mild assumptions, a set is rectifiable if and only if its
Hausdorff measure is lower semi-continuous under bounded Lipschitz
perturbations.


title: Bag of Tricks for Efficient Text Classification

abstract:
  This paper explores a simple and efficient baseline for text classification.
Our experiments show that our fast text classifier fastText is often on par
with deep learning classifiers in terms of accuracy, and many orders of
magnitude faster for training and evaluation. We can train fastText on more
than one billion words in less than ten minutes using a standard multicore~CPU,
and classify half a million sentences among~312K classes in less than a minute.


title:
Information-theoretic thresholds for community detection in sparse
  networks

abstract:
  We give upper and lower bounds on the information-theoretic threshold for
community detection in the stochastic block model. Specifically, consider the
symmetric stochastic block model with $q$ groups, average degree $d$, and
connection probabilities $c_\text{in}/n$ and $c_\text{out}/n$ for within-group
and between-group edges respectively; let $\lambda =
(c_\text{in}-c_\text{out})/(qd)$. We show that, when $q$ is large, and $\lambda
= O(1/q)$, the critical value of $d$ at which community detection becomes
possible---in physical terms, the condensation threshold---is \[ d_\text{c} =
\Theta\!\left( \frac{\log q}{q \lambda^2} \right) \, , \] with tighter results
in certain regimes. Above this threshold, we show that any partition of the
nodes into $q$ groups which is as `good' as the planted one, in terms of the
number of within- and between-group edges, is correlated with it. This gives an
exponential-time algorithm that performs better than chance; specifically,
community detection becomes possible below the Kesten-Stigum bound for $q \ge
5$ in the disassortative case $\lambda < 0$, and for $q \ge 11$ in the
assortative case $\lambda >0$ (similar upper bounds were obtained independently
by Abbe and Sandon). Conversely, below this threshold, we show that no
algorithm can label the vertices better than chance, or even distinguish the
block model from an \ER\ random graph with high probability.
  Our lower bound on $d_\text{c}$ uses Robinson and Wormald's small subgraph
conditioning method, and we also give (less explicit) results for non-symmetric
stochastic block models. In the symmetric case, we obtain explicit results by
using bounds on certain functions of doubly stochastic matrices due to
Achlioptas and Naor; indeed, our lower bound on $d_\text{c}$ is their second
moment lower bound on the $q$-colorability threshold for random graphs with a
certain effective degree.

categories: math.PR cond-mat.stat-mech cs.CC cs.IT cs.SI math.IT


title:
Looking through the same lens: shear calibration for LSST, Euclid &
  WFIRST with stage 4 CMB lensing

abstract:
  The next generation weak lensing surveys (i.e., LSST, Euclid and WFIRST) will
require exquisite control over systematic effects. In this paper, we address
shear calibration and present the most realistic forecast to date for
LSST/Euclid/WFIRST and CMB lensing from a stage 4 CMB experiment (CMB S4). We
use the CosmoLike code to simulate a joint analysis of all the two-point
functions of galaxy density, galaxy shear and CMB lensing convergence. We
include the full Gaussian and non-Gaussian covariances and explore the
resulting joint likelihood with Monte Carlo Markov Chains. We constrain shear
calibration biases while simultaneously varying cosmological parameters, galaxy
biases and photometric redshift uncertainties. We find that CMB lensing from
CMB S4 enables the calibration of the shear biases down to 0.2% - 3% in 10
tomographic bins for LSST (below the ~0.5% requirements in most tomographic
bins), down to 0.4% - 2.4% in 10 bins for Euclid and 0.6% - 3.2% in 10 bins for
WFIRST. For a given lensing survey, the method works best at high redshift
where shear calibration is otherwise most challenging. This self-calibration is
robust to Gaussian photometric redshift uncertainties and to a reasonable level
of intrinsic alignment. It is also robust to changes in the beam and the
effectiveness of the component separation of the CMB experiment, and slowly
dependent on its depth, making it possible with third generation CMB
experiments such as AdvACT and SPT-3G, as well as the Simons Observatory.


title: Inventory Accumulation with $k$ Products

abstract:
  Sheffield (2011) proposed an inventory accumulation model with two types of
products to study the critical Fortuin-Kasteleyn model on a random planar map,
and showed that a two-dimensional inventory accumulation trajectory in the
discrete model scales to a correlated planar Brownian motion. In this work, we
generalize the inventory model to $k$ types of products for any integer $k \ge
2$, and prove that the corresponding trajectory scales to a $k$-dimensional
Brownian motion with an appropriate covariance matrix.


title:
The infinitesimal multiplicities and orientations of the blow-up set of
  the Seiberg-Witten equation with multiple spinors

abstract:
  I construct multiplicies and orientations of tangent cones to any blow-up set
$Z$ for the Seiberg-Witten equation with multiple spinors. This is used to
prove that $Z$ determines a homology class, which is shown to be equal to the
Poincar\'{e} dual of the first Chern class of the determinant line bundle. I
also obtain a lower bound for the 1-dimensional Hausdorff measure of $Z$.


title: Tunnelling necessitates negative Wigner function

abstract:
  We consider in what sense quantum tunnelling is associated with non-classical
probabilistic behaviour. We use the Wigner function quasi-probability
description of quantum states. We give a definition of tunnelling that allows
us to say whether in a given scenario there is tunnelling or not. We prove that
this can only happen if either the Wigner function is negative and/or a certain
measurement operator which we call the tunnelling rate operator has a negative
Wigner function.


title: The mathematics of lecture hall partitions

abstract:
  Over the past twenty years, lecture hall partitions have emerged as
fundamental combinatorial structures, leading to new generalizations and
interpretations of classical theorems and new results. In recent years,
geometric approaches to lecture hall partitions have used polyhedral geometry
to discover further properties of these rich combinatorial objects.
  In this paper we give an overview of some of the surprising connections that
have surfaced in the process of trying to understand the lecture hall
partitions.


title:
Simultaneous Use of Cs and Rb Rydberg Atoms for Independent RF Electric
  Field Measurements via Electromagnetically Induced Transparency

abstract:
  We demonstrate simultaneous electromagnetically-induced transparency (EIT)
with cesium (Cs) and rubidium (Rb) Rydberg atoms in the same vapor cell with
coincident (overlapping) optical fields. Each atomic system can detect radio
frequency (RF) electric (E) field strengths through modification of the EIT
signal (Autler-Townes (AT) splitting), which leads to a direct SI traceable RF
E-field measurement. We show that these two systems can detect the same the RF
E-field strength simultaneously, which provides a direct in situ comparison of
Rb and Cs RF measurements in Rydberg atoms. In effect, this allows us to
perform two independent measurements of the same quantity in the same
laboratory, providing two different immediate and independent measurements.
This gives two measurements that helps rule out systematic effects and
uncertainties in this E-field metrology approach, which are important when
establishing an international measurement standard for an E-field strength and
is a necessary step for this method to be accepted as a standard calibration
technique. We use this approach to measure E-fields at 9.2~GHz, 11.6~GHz, and
13.4~GHz, which correspond to three different atomic states (different
principal atomic numbers and angular momentums) for the two atom species.


title: Super no-scale models in string theory

abstract:
  We consider "super no-scale models" in the framework of the heterotic string,
where the N=4,2,1 --> 0 spontaneous breaking of supersymmetry is induced by
geometrical fluxes realizing a stringy Scherk-Schwarz perturbative mechanism.
Classically, these backgrounds are characterized by a boson/fermion degeneracy
at the massless level, even if supersymmetry is broken. At the 1-loop level,
the vacuum energy is exponentially suppressed, provided the supersymmetry
breaking scale is small, m_{3/2} << M_{string}. We show that the "super
no-scale string models" under consideration are free of Hagedorn-like tachyonic
singularities, even when the supersymmetry breaking scale is large, m_{3/2} ~
M_{string}. The vacuum energy decreases monotonically and converges
exponentially to zero, when m_{3/2} varies from M_{string} to 0. We also show
that all Wilson lines associated to asymptotically free gauge symmetries are
dynamically stabilized by the 1-loop effective potential, while those
corresponding to non-asymtotically free gauge groups lead to instabilities and
condense. The Wilson lines of the conformal gauge symmetries remain massless.
When stable, the stringy super no-scale models admit low energy effective
actions, where decoupling gravity yields theories in flat spacetime, with
softly broken supersymmetry.


title: On the origin of nonclassicality in single systems

abstract:
  In the framework of certain general probability theories of single systems,
we identify various nonclassical features such as incompatibility, multiple
pure-state decomposability, measurement disturbance, no-cloning and the
impossibility of certain universal operations, with the non-simpliciality of
the state space. This is shown to naturally suggest an underlying simplex as an
ontological model. Contextuality turns out to be an independent nonclassical
feature, arising from the intransitivity of compatibility.


title: Detecting patchy reionization in the CMB

abstract:
  Upcoming cosmic microwave background (CMB) experiments will measure
temperature fluctuations on small angular scales with unprecedented precision.
Small-scale CMB fluctuations are a mixture of late-time effects: gravitational
lensing, Doppler shifting of CMB photons by moving electrons (the kSZ effect),
and residual foregrounds. We propose a new statistic which separates the kSZ
signal from the others, and also allows the kSZ signal to be decomposed in
redshift bins. The decomposition extends to high redshift, and does not require
external datasets such as galaxy surveys. In particular, the high-redshift
signal from patchy reionization can be cleanly isolated, enabling future CMB
experiments to make high-significance and qualitatively new measurements of the
reionization era.


title: Charge-4e superconductors: a Majorana quantum Monte Carlo study

abstract:
  Many features of charge-4e superconductors remain unknown because even the
"mean-field Hamiltonian" describing them is an interacting model. Here we
introduce an interacting model to describe a charge-4e superconductor (SC) deep
in the superconducting phase, and explore its properties using quantum Monte
Carlo (QMC) simulations. The QMC is sign-problem-free, but only when a Majorana
representation is employed. As a function of the chemical potential we observe
two sharply-distinct behaviors: a "strong" quarteting phase in which charge-4e
quartets are tightly bound (like molecules) so that charge-2e pairing does not
occur even in the temperature $T \to 0$ limit, and a "weak" quarteting phase in
which a further transition to a charge-2e superconducting phase occurs at a
lower critical temperature. Analogous issues arise in a putative Z4 spin-liquid
with a pseudo-Fermi surface and in characterizing charge-2e SCs with "odd
frequency pairing" (or equivalently with a "composite order parameter") and
metallic spin-nematics. Under certain circumstances, we also identified a
stable T=0 charge-4e SC phase with gapless nodal quasiparticles. We further
discuss possible relevance of our results to various experimental observations
in 1/8-doped LBCO.


title:
Entanglement Entropy and Mutual Information of Circular Entangling
  Surfaces in 2 + 1-dimensional Quantum Lifshitz Model

abstract:
  We investigate the entanglement entropy (EE) of circular entangling cuts in
the 2+1-dimensional quantum Lifshitz model, whose ground state wave function is
a spatially conformal invariant state of the Rokhsar-Kivelson type, whose
weight is the Gibbs weight of 2D Euclidean free boson. We show that the finite
subleading corrections of EE to the area-law term as well as the mutual
information are conformal invariants and calculate them for cylinder, disk-like
and spherical manifolds with various spatial cuts. The subtlety due to the
boson compactification in the replica trick is carefully addressed. We find
that in the geometry of a punctured plane with many small holes, the constant
piece of EE is proportional to the number of holes, indicating the ability of
entanglement to detect topological information of the configuration. Finally,
we compare the mutual information of two small distant disks with Cardy's
relativistic CFT scaling proposal. We find that in the quantum Lifshitz model,
the mutual information also scales at long distance with a power determined by
the lowest scaling dimension local operator in the theory.


title: X-Rays Beware: The Deepest Chandra Catalogue of Point Sources in M31

abstract:
  This study represents the most sensitive Chandra X-ray point source catalogue
of M31. Using 133 publicly available Chandra ACIS-I/S observations totalling ~1
Ms, we detected 795 X-ray sources in the bulge, northeast, and southwest fields
of M31, covering an area of approximately 0.6 deg$^{2}$, to a limiting
unabsorbed 0.5-8.0 keV luminosity of $10^{34}$ erg/s. In the inner bulge, where
exposure is approximately constant, X-ray fluxes represent average values
because they were determined from many observations over a long period of time.
Similarly, our catalogue is more complete in the bulge fields since monitoring
allowed more transient sources to be detected. The catalogue was
cross-correlated with a previous XMM-Newton catalogue of M31's $D_{25}$
isophote consisting of 1948 X-ray sources, with only 979 within the field of
view of our survey. We found 387 (49%) of our Chandra sources (352 or 44%
unique sources) matched to within 5 arcsec of 352 XMM-Newton sources. Combining
this result with matching done to previous Chandra X-ray sources we detected
259 new sources in our catalogue. We created X-ray luminosity functions (XLFs)
in the soft (0.5-2.0 keV) and hard (2.0-8.0 keV) bands that are the most
sensitive for any large galaxy based on our detection limits.
Completeness-corrected XLFs show a break around $1.3\times10^{37}$ erg/s,
consistent with previous work. As in past surveys, we find the bulge XLFs are
flatter than the disk, indicating a lack of bright high-mass X-ray binaries in
the disk and an aging population of low-mass X-ray binaries in the bulge.


title:
High-order harmonic generation in polyatomic molecules induced by a
  bicircular laser field

abstract:
  High-order harmonic generation by a bicircular field, which consists of two
coplanar counter-rotating circularly polarized fields of frequency $r\omega$
and $s\omega$ ($r$ and $s$ are integers), is investigated for a polyatomic
molecule. This field possesses dynamical symmetry, which can be adjusted to the
symmetry of the molecular Hamiltonian and used to investigate the molecular
symmetry. For polyatomic molecules having the $C_{r+s}$ symmetry only the
harmonics $n=q(r+s)\pm r$, $q=1,2,\ldots$, are emitted having the ellipticity
$\varepsilon_n=\pm 1$. We illustrate this using the example of the planar
molecules BH$_3$ and BF$_3$, which obey the $C_3$ symmetry. We show that for
the BF$_3$ molecule, similarly to atoms with a $p$ ground state, there is a
strong asymmetry in the emission of high harmonics with opposite helicities.
This asymmetry depends on the molecular orientation.


title: Quantum teleportation and Birman-Murakami-Wenzl algebra

abstract:
  In this paper, we investigate the relationship of quantum teleportation in
quantum information science and the Birman-Murakami-Wenzl (BMW) algebra in
low-dimensional topology. For simplicity, we focus on the two spin-1/2
representation of the BMW algebra, which is generated by both the
Temperley-Lieb projector and the Yang-Baxter gate. We describe quantum
teleportation using the Temperley-Lieb projector and the Yang-Baxter gate,
respectively, and study teleportation-based quantum computation using the
Yang-Baxter gate. On the other hand, we exploit the extended Temperley-Lieb
diagrammatical approach to clearly show that the tangle relations of the BMW
algebra have a natural interpretation of quantum teleportation. Inspired by
this interpretation, we construct a general representation of the tangle
relations of the BMW algebra and obtain interesting representations of the BMW
algebra. Therefore our research sheds a light on a link between quantum
information science and low-dimensional topology.


title: Gambling on the existence of other universes

abstract:
  Speculations and theories about the existence of other worlds have a long
history. In recent times, the arguments have shifted away from their typical
philosophical and theological character to supposedly become more objective
thanks to their scientific underpinnings. A prime example of this is the
current parallel universes or multiverse theory, which has the support of a
number of famous cosmologists. In this article, we contend that the claim for
the existence of those parallel universes, as presented in Max Tegmark's book
"Our Mathematical Universe", rests crucially on some questionable probability
arguments involving infinity. As a result, a doubt is cast over the multiverse
hypothesis: Is it more credible than the counterarguments based on
philosophical and metaphysical considerations?


title:
In-focus wavefront sensing using non-redundant mask-induced pupil
  diversity

abstract:
  Wavefront estimation using in-focus image data is critical to many
applications. This data is invariant to a sign flip with complex conjugation of
the complex amplitude in the pupil, making for a non-unique solution.
Information from an in-focus image taken through a non-redundant pupil mask
(NRM) can break this ambiguity, enabling the true aberration to be determined.
We demonstrate this by priming a full pupil Gerchberg-Saxton phase retrieval
with NRM fringe phase information. We apply our method to measure simulated
aberrations on the segmented James Webb Space Telescope (JWST) mirror using
full pupil and NRM data from its Near Infrared Imager and Slitless Spectrograph
(NIRISS).


title:
Tracking Neptune's Migration History through High-Perihelion Resonant
  Trans-Neptunian Objects

abstract:
  Recently, Sheppard et al. (2016) presented the discovery of seven new
trans-Neptunian objects with moderate eccentricities, perihelia beyond 40 AU,
and semimajor axes beyond 50 AU. Like the few previously known objects on
similar orbits, these objects' semimajor axes are just beyond the Kuiper belt
edge and clustered around Neptunian mean motion resonances (MMRs). These
objects likely obtained their observed orbits while trapped within MMRs, when
the Kozai-Lidov mechanism raised their perihelia and weakened Neptune's
dynamical influence. Using numerical simulations that model the production of
this population, we find that high-perihelion objects near Neptunian MMRs can
constrain the nature and timescale of Neptune's past orbital migration. In
particular, the population near the 3:1 MMR (near 62 AU) is especially useful
due to its large population and short dynamical evolution timescale. If Neptune
finishes migrating within ~100 Myrs or less, we predict over 90% of
high-perihelion objects near the 3:1 MMR will have semimajor axes within 1 AU
of each other, very near the modern resonance's center. On the other hand, if
Neptune's migration takes ~300 Myrs, we expect ~50% of this population to
reside in dynamically fossilized orbits over ~1 AU closer to the Sun than the
modern resonance. We highlight 2015 KH162 as a likely member of this fossilized
3:1 population. Under any plausible migration scenario, nearly all
high-perihelion objects in resonances beyond the 4:1 MMR (near 76 AU) reach
their orbits well after Neptune stops migrating and comprise a recently
generated, dynamically active population.


title: Feynman Path Integrals Over Entangled States

abstract:
  The saddle points of a conventional Feynman path integral are not entangled,
since they comprise a sequence of classical field configurations. We combine
insights from field theory and tensor networks by constructing a Feynman path
integral over a sequence of matrix product states. The paths that dominate this
path integral include some degree of entanglement. This new feature allows
several insights and applications: i. A Ginzburg-Landau description of
deconfined phase transitions. ii. The emergence of new classical collective
variables in states that are not adiabatically continuous with product states.
iii. Features that are captured in product-state field theories by
proliferation of instantons are encoded in perturbative fluctuations about
entangled saddles. We develop a general formalism for such path integrals and a
couple of simple examples to illustrate their utility.


title: The Molecular Clouds Fueling a 1/5 Solar Metallicity Starburst

abstract:
  Using the Atacama Large Millimeter/submillimeter Array, we have made the
first high spatial and spectral resolution observations of the molecular gas
and dust in the prototypical blue compact dwarf galaxy II Zw 40. The CO(2-1)
and CO(3-2) emission is clumpy and distributed throughout the central
star-forming region. Only one of eight molecular clouds has associated star
formation. The continuum spectral energy distribution is dominated by free-free
and synchrotron: at 870$\mu m$, only 50% of the emission is from dust. We
derive a CO-to-H$_2$ conversion factor by several methods including a new
method that uses simple photodissocation models and resolved CO line intensity
measurements to derive a relationship that uniquely predicts $\alpha_{CO}$ for
a given metallicity. We find that the CO-to-H$_2$ conversion factor is 4 to 35
times that of the Milky Way (18.1 to 150.5 M$_\odot$ / (K km/s pc$^2$)). The
star formation efficiency of the molecular gas at least 10 times higher than
that found in normal spiral galaxies, which is likely due to the
burst-dominated star formation history of II Zw 40 rather than an intrinsically
higher efficiency. The molecular clouds within II Zw 40 resemble those in other
strongly interacting systems like the Antennae: overall they have high
size-linewidth coefficients and molecular gas surface densities. These
properties appear to be due to the high molecular gas surface densities
produced in this merging system rather than to increased external pressure.
Overall, these results paint a picture of II Zw 40 as a complex, rapidly
evolving system whose molecular gas properties are dominated by the large-scale
gas shocks from its on-going merger.


title:
Disk reflection and a possible disk wind during a soft X-ray state in
  the neutron star low-mass X-ray binary 1RXS J180408.9-342058

abstract:
  1RXS J180408.9-342058 is a transient neutron star low-mass X-ray binary that
exhibited a bright accretion outburst in 2015. We present Nustar, Swift, and
Chandra observations obtained around the peak of this outburst. The source was
in a soft X-ray spectral state and displayed an X-ray luminosity of Lx~(2-3)E37
(D/5.8 kpc)^2 erg cm-2 (0.5-10 keV). The Nustar data reveal a broad Fe-K
emission line that we model as relativistically broadened reflection to
constrain the accretion geometry. We found that the accretion disk is viewed at
an inclination of i~27-35 degrees and extended close to the neutron star, down
to Rin~5-7.5 gravitational radii (~11-17 km). This inner disk radius suggests
that the neutron star magnetic field strength is B<2E8 G. We find a narrow
absorption line in the Chandra/HEG data at an energy of ~7.64 keV with a
significance of ~4.8 sigma. This feature could correspond to blue-shifted Fe
xxvi and arise from an accretion disk wind, which would imply an outflow
velocity of v~0.086c (~25800 km s-1). However, this would be extreme for an
X-ray binary and it is unclear if a disk wind should be visible at the low
inclination angle that we infer from our reflection analysis. Finally, we
discuss how the X-ray and optical properties of 1RXS J180408.9-342058 are
consistent with a relatively small (Porb<3 hr) binary orbit.


title:
Stratifying On-Shell Cluster Varieties: the Geometry of Non-Planar
  On-Shell Diagrams

abstract:
  The correspondence between on-shell diagrams in maximally supersymmetric
Yang-Mills theory and cluster varieties in the Grassmannian remains largely
unexplored beyond the planar limit. In this article, we describe a systematic
program to survey such 'on-shell varieties', and use this to provide a complete
classification in the case of $G(3,6)$. In particular, we find exactly 24
top-dimensional varieties and 10 co-dimension one varieties in $G(3,6)$---up to
parity and relabeling of the external legs. We use this case to illustrate some
of the novelties found for non-planar varieties relative to the case of
positroids, and describe some of the features that we expect to hold more
generally.


title:
Approximate Bayesian Computation in Large Scale Structure: constraining
  the galaxy-halo connection

abstract:
  Standard approaches to Bayesian parameter inference in large scale structure
assume a Gaussian functional form (chi-squared form) for the likelihood. This
assumption, in detail, cannot be correct. Likelihood free inferences such as
Approximate Bayesian Computation (ABC) relax these restrictions and make
inference possible without making any assumptions on the likelihood. Instead
ABC relies on a forward generative model of the data and a metric for measuring
the distance between the model and data. In this work, we demonstrate that ABC
is feasible for LSS parameter inference by using it to constrain parameters of
the halo occupation distribution (HOD) model for populating dark matter halos
with galaxies.
  Using specific implementation of ABC supplemented with Population Monte Carlo
importance sampling, a generative forward model using HOD, and a distance
metric based on galaxy number density, two-point correlation function, and
galaxy group multiplicity function, we constrain the HOD parameters of mock
observation generated from selected "true" HOD parameters. The parameter
constraints we obtain from ABC are consistent with the "true" HOD parameters,
demonstrating that ABC can be reliably used for parameter inference in LSS.
Furthermore, we compare our ABC constraints to constraints we obtain using a
pseudo-likelihood function of Gaussian form with MCMC and find consistent HOD
parameter constraints. Ultimately our results suggest that ABC can and should
be applied in parameter inference for LSS analyses.


title:
Reducing detection noise of a photon pair in a dispersive medium by
  controlling its spectral entanglement

abstract:
  Chromatic dispersion is one of the main limitations to the security of
quantum communication protocols that rely on the transmission of single photons
in single mode fibers. This phenomenon forces the trusted parties to define
longer detection windows to avoid losing signal photons and increases the
amount of detection noise that is being registered. In this work, we analyze
the effects of chromatic dispersion on a photon pair generated via spontaneous
parametric down-conversion and propagating in standard telecommunication
fibers. We also present the possibility of reducing the detection noise by
manipulating the spectral correlation of the pair. As an example, we show that
our results can be used to increase the maximal security distance of a
discrete-variable quantum key distribution scheme in which the photon source is
located between the legitimate participants of the protocol.


title: On the curious spectrum of duality invariant higher-derivative gravity

abstract:
  We analyze the spectrum of the exactly duality and gauge invariant
higher-derivative double field theory. While this theory is based on a chiral
CFT and does not correspond to a standard string theory, our analysis
illuminates a number of issues central in string theory. The full quadratic
action is rewritten as a two-derivative theory with additional fields. This
allows for a simple analysis of the spectrum, which contains two massive spin-2
ghosts and massive scalars, in addition to the massless fields. Moreover, in
this formulation, the massless or tensionless limit $\alpha'\rightarrow \infty$
is non-singular and leads to an enhanced gauge symmetry. We show that the
massive modes can be integrated out exactly at the quadratic level, leading to
an infinite series of higher-derivative corrections. Finally, we present a
ghost-free massive extension of linearized double field theory, which employs a
novel mass term for the dilaton and metric.


title:
Low Gas Fractions Connect Compact Star-Forming Galaxies to their z ~ 2
  Quiescent Descendants

abstract:
  Early quiescent galaxies at z~2 are known to be remarkably compact compared
to their nearby counterparts. Possible progenitors of these systems include
galaxies that are structurally similar, but are still rapidly forming stars.
Here, we present Karl G. Jansky Very Large Array (VLA) observations of the
CO(1-0) line towards three such compact, star-forming galaxies at z~2.3,
significantly detecting one. The VLA observations indicate baryonic gas
fractions >~5 times lower and gas depletion times >~10 times shorter than
normal, extended massive star-forming galaxies at these redshifts. At their
current star formation rates, all three objects will deplete their gas
reservoirs within 100Myr. These objects are among the most gas-poor objects
observed at z>2, and are outliers from standard gas scaling relations, a result
which remains true regardless of assumptions about the CO-H2 conversion factor.
Our observations are consistent with the idea that compact, star-forming
galaxies are in a rapid state of transition to quiescence in tandem with the
build-up of the z~2 quenched population. In the detected compact galaxy, we see
no evidence of rotation or that the CO-emitting gas is spatially extended
relative to the stellar light. This casts doubt on recent suggestions that the
gas in these compact galaxies is rotating and significantly extended compared
to the stars. Instead, we suggest that, at least for this object, the gas is
centrally concentrated, and only traces a small fraction of the total galaxy
dynamical mass.


title: Relaxation from particle production

abstract:
  We consider using particle production as a friction force by which to
implement a "Relaxion" solution to the electroweak hierarchy problem. Using
this approach, we are able to avoid superplanckian field excursions and avoid
any conflict with the strong CP problem. The relaxation mechanism can work
before, during or after inflation allowing for inflationary dynamics to play an
important role or to be completely decoupled.


title: Linear magnetochiral effect in Weyl semimetals

abstract:
  We suggest the possibility of a linear magnetochiral effect in time reversal
breaking Weyl semimetals. Generically the magnetochiral effect consists in a
simultaneous linear dependence of the magnetotransport coefficients with the
magnetic field and a momentum vector. This simultaneous dependence is allowed
by the Onsager reciprocity relations, being the separation vector between the
Weyl nodes the vector that plays such role. As a side consequence, we find a
non vanishing positive longitudinal magnetoconductivity at Fermi energies above
the point where the chirality of the Weyl nodes is globally lost.


title:
Hydrodynamical Coupling of Mass and Momentum in Multiphase Galactic
  Winds

abstract:
  Using a set of high resolution hydrodynamical simulations run with the Cholla
code, we investigate how mass and momentum couple to the multiphase components
of galactic winds. The simulations model the interaction between a hot wind
driven by supernova explosions and a cooler, denser cloud of interstellar or
circumgalactic media. By resolving scales of $\Delta x<0.1$ pc over $>100$ pc
distances our calculations capture how the cloud disruption leads to a
distribution of densities and temperatures in the resulting multiphase outflow,
and quantify the mass and momentum associated with each phase. We find the
multiphase wind contains comparable mass and momenta in phases over a wide
range of densities and temperatures extending from the hot wind ($n \approx
10^{-2.5}$ $\mathrm{cm}^{-3}$, $T \approx 10^{6.5}$ K) to the coldest
components ($n \approx 10^2$ $\mathrm{cm}^{-3}$, $T \approx 10^2$ K). We
further find that the momentum distributes roughly in proportion to the mass in
each phase, and the mass-loading of the hot phase by the destruction of cold,
dense material is an efficient process. These results provide new insight into
the physical origin of observed multiphase galactic outflows, and inform galaxy
formation models that include coarser treatments of galactic winds. Our results
confirm that cool gas observed in outflows at large distances from the galaxy
($\gtrsim1$kpc) likely does not originate through the entrainment of cold
material near the central starburst.


title: Probing sub-GeV Dark Matter with conventional detectors

abstract:
  The direct detection of Dark Matter particles with mass below the GeV-scale
is hampered by soft nuclear recoil energies and finite detector thresholds. For
a given maximum relative velocity, the kinematics of elastic Dark Matter
nucleus scattering sets a principal limit on detectability. Here we propose to
bypass the kinematic limitations by considering the inelastic channel of photon
emission in the nuclear recoil. Our proposed method allows to set the first
limits on Dark Matter below 500 MeV in the plane of Dark Matter mass and cross
section with nucleons. In situations where a Dark Matter-electron coupling is
suppressed, Bremsstrahlung may constitute the only path to probe low-mass Dark
Matter awaiting new detector technologies with lowered recoil energy
thresholds.


title:
H0LiCOW V. New COSMOGRAIL time delays of HE0435-1223: $H_0$ to 3.8%
  precision from strong lensing in a flat $\Lambda$CDM model

abstract:
  We present a new measurement of the Hubble Constant H0 and other cosmological
parameters based on the joint analysis of three multiply-imaged quasar systems
with measured gravitational time delays. First, we measure the time delay of
HE0435-1223 from 13-year light curves obtained as part of the COSMOGRAIL
project. Companion papers detail the modeling of the main deflectors and line
of sight effects, and how these data are combined to determine the time-delay
distance of HE 0435-1223. Crucially, the measurements are carried out blindly
with respect to cosmological parameters in order to avoid confirmation bias. We
then combine the time-delay distance of HE0435-1223 with previous measurements
from systems B1608+656 and RXJ1131-1231 to create a Time Delay Strong Lensing
probe (TDSL). In flat $\Lambda$CDM with free matter and energy density, we find
$H_0$ = 71.9 +2.4 -3.0 km/s/Mpc and $\Omega_{\Lambda}$ = 0.62 +0.24 -0.35 .
This measurement is completely independent of, and in agreement with, the local
distance ladder measurements of H0. We explore more general cosmological models
combining TDSL with other probes, illustrating its power to break degeneracies
inherent to other methods. The TDSL and Planck joint constraints are $H_0$ =
69.2 +1.4 -2.2 km/s/Mpc, $\Omega_{\Lambda}$ = 0.70 +0.01 -0.01 and $\Omega_k$ =
0.003 +0.004 -0.006 in open $\Lambda$CDM and $H_0$ = 79.0 +4.4 -4.2 km/s/Mpc,
$\Omega_{de}$ = 0.77 +0.02 -0.03 and $w$ = -1.38 +0.14 -0.16 in flat $w$CDM.
Combined with Planck and Baryon Acoustic Oscillation data, when relaxing the
constraints on the numbers of relativistic species we find $N_{eff}$ = 3.34
+0.21 -0.21 and when relaxing the total mass of neutrinos we find 0.182 eV. In
an open $w$CDM in combination with Planck and CMB lensing we find $H_0$ = 77.9
+5.0 -4.2 km/s/Mpc, $\Omega_{de}$ = 0.77 +0.03 -0.03, $\Omega_k$ = -0.003
+0.004 -0.004 and $w$ = -1.37 +0.18 -0.23.


title:
Binary Neutron Star Mergers and Short Gamma-Ray Bursts: Effects of
  Magnetic Field Orientation, Equation of State, and Mass Ratio

abstract:
  We present fully GRMHD simulations of the merger of binary neutron star (BNS)
systems. We consider BNSs producing a hypermassive neutron star (HMNS) that
collapses to a spinning black hole (BH) surrounded by a magnetized accretion
disk in a few tens of ms. We investigate whether such systems may launch
relativistic jets and power short gamma-ray bursts. We study the effects of
different equations of state (EOSs), different mass ratios, and different
magnetic field orientations. For all cases, we present a detailed investigation
of the matter dynamics and of the magnetic field evolution, with particular
attention to its global structure and possible emission of relativistic jets.
The main result of this work is that we found the formation of an organized
magnetic field structure. This happens independently of EOS, mass ratio, and
initial magnetic field orientation. We also show that those models that produce
a longer-lived HMNS lead to a stronger magnetic field before collapse to BH.
Such larger fields make it possible, for at least one of our models, to resolve
the MRI and hence further amplify the magnetic field. However, by the end of
our simulations, we do not observe a magnetically dominated funnel and hence
neither a relativistic outflow. With respect to the recent simulations of Ruiz
et al 2016, we evolve models with lower and more realistic initial magnetic
field strengths and, because of computational reasons, we do not evolve the
accretion disk for the long timescales that seem to be required in order to see
a relativistic outflow. Since all our models produce a similar ordered magnetic
field structure, we expect that the results found in Ruiz et al 2016, where
they only considered an equal-mass system with an ideal fluid EOS, should be
general and, at least from a qualitative point of view, independent from
mass-ratio, magnetic field orientation, and EOS.


title:
Self-Destructing Spiral Waves: Global Simulations of a Spiral Wave
  Instability in Accretion Disks

abstract:
  We present results from a suite of three-dimensional global hydrodynamic
simulations which show that spiral density waves propagating in circumstellar
disks are unstable to the growth of a parametric instability that leads to
break-down of the flow into turbulence. This spiral wave instability (SWI)
arises from a resonant interaction between pairs of inertial waves, or
inertial-gravity waves, and the background spiral wave. The development of the
instability in the linear regime involves the growth of a broad spectrum of
inertial modes, with growth rates on the order of the orbital time, and results
in a nonlinear saturated state in which turbulent velocity perturbations are of
a similar magnitude to those induced by the spiral wave. The turbulence induces
angular momentum transport, and vertical mixing, at a rate that depends locally
on the amplitude of the spiral wave (we obtain a stress parameter $\alpha \sim
5 \times 10^{-4}$ in our reference model). The instability is found to operate
in a wide-range of disk models, including those with isothermal or adiabatic
equations of state, and in viscous disks where the dimensionless kinematic
viscosity $\nu\le 10^{-5}$. This robustness suggests that the instability will
have applications to a broad range of astrophysical disk-related phenomena,
including those in close binary systems, planets embedded in protoplanetary
disks (including Jupiter in our own Solar System) and FU Orionis outburst
models. Further work is required to determine the nature of the instability,
and to evaluate its observational consequences, in physically more complete
disk models than we have considered in this paper.


title:
Searching for high-energy gamma-ray counterparts to Gravitational Wave
  sources with Fermi-LAT: a needle in a haystack

abstract:
  At least a fraction of Gravitational Wave (GW) progenitors are expected to
emit an electromagnetic (EM) signal in the form of a short gamma-ray burst
(sGRB). Discovering such a transient EM counterpart is challenging because the
\LIGO/\VIRGO localization region is much larger (several hundreds of square
degrees) than the field of view of X-ray, optical and radio telescopes. The
Fermi Large Area Telescope (LAT) has a wide field of view ($\sim 2.4$ sr), and
detects $\sim 2-3$ sGRBs per year above 100 MeV. It can detect them not only
during the short prompt phase, but also during their long-lasting high-energy
afterglow phase. If other wide-field high-energy instruments such as Fermi-GBM,
Swift-BAT or INTEGRAL-ISGRI cannot detect or localize with enough precision an
EM counterpart during the prompt phase, the LAT can potentially pinpoint it
with $\lesssim 10$ arcmin accuracy during the afterglow phase. This routinely
happens with gamma-ray bursts. Moreover, the LAT will cover the entire
localization region within hours of any triggers during normal operations,
allowing the $\gamma$-ray flux of any EM counterpart to be measured or
constrained. We illustrate two new ad hoc methods to search for EM counterparts
with the LAT and their application to the GW candidate LVT151012.


title: VideoLSTM Convolves, Attends and Flows for Action Recognition

abstract:
  We present a new architecture for end-to-end sequence learning of actions in
video, we call VideoLSTM. Rather than adapting the video to the peculiarities
of established recurrent or convolutional architectures, we adapt the
architecture to fit the requirements of the video medium. Starting from the
soft-Attention LSTM, VideoLSTM makes three novel contributions. First, video
has a spatial layout. To exploit the spatial correlation we hardwire
convolutions in the soft-Attention LSTM architecture. Second, motion not only
informs us about the action content, but also guides better the attention
towards the relevant spatio-temporal locations. We introduce motion-based
attention. And finally, we demonstrate how the attention from VideoLSTM can be
used for action localization by relying on just the action class label.
Experiments and comparisons on challenging datasets for action classification
and localization support our claims.


title: Variable Stars in the Quintuplet stellar cluster with the VVV Survey

abstract:
  The Quintuplet cluster is one of the most massive star clusters in the Milky
Way, situated very close to the Galactic center. We present a new search for
variable stars in the vicinity of the cluster, using the five-year database of
the Vista Variables in the Via Lactea (VVV) ESO Public Survey in the
near-infrared. A total of 7586 objects were identified in the zone around $2'$
from the cluster center, using 55 $K_S$-band epochs. Thirty-three stars show
$K_S$-band variability, 24 of them being previously undiscovered. Most of the
variable stars found are slow/semiregular variables, long-period variables of
the Mira type, and OH/IR stars. In addition, a good number of our candidates
show variations in a rather short timescale. We also propose four Young Stellar
Object (YSO) candidates, which could be cluster members.


title: Entropy accumulation

abstract:
  We ask the question whether entropy accumulates, in the sense that the
operationally relevant total uncertainty about an $n$-partite system $A = (A_1,
\ldots A_n)$ corresponds to the sum of the entropies of its parts $A_i$. The
Asymptotic Equipartition Property implies that this is indeed the case to first
order in $n$, under the assumption that the parts $A_i$ are identical and
independent of each other. Here we show that entropy accumulation occurs more
generally, i.e., without an independence assumption, provided one quantifies
the uncertainty about the individual systems $A_i$ by the von Neumann entropy
of suitably chosen conditional states. The analysis of a large system can hence
be reduced to the study of its parts. This is relevant for applications. In
device-independent cryptography, for instance, the approach yields essentially
optimal security bounds valid for general attacks, as shown by Arnon-Friedman
et al.


title: Simple and tight device-independent security proofs

abstract:
  Device-independent security is the gold standard for quantum cryptography:
not only is security based entirely on the laws of quantum mechanics, but it
holds irrespective of any a priori assumptions on the quantum devices used in a
protocol, making it particularly applicable in a quantum-wary environment.
While the existence of device-independent protocols for tasks such as
randomness expansion and quantum key distribution has recently been
established, the underlying proofs of security remain very challenging, yield
rather poor key rates, and demand very high-quality quantum devices, thus
making them all but impossible to implement in practice.
  We introduce a technique for the analysis of device-independent cryptographic
protocols. We provide a flexible protocol and give a security proof that
provides quantitative bounds that are asymptotically tight, even in the
presence of general quantum adversaries. At a high level our approach amounts
to establishing a reduction to the scenario in which the untrusted device
operates in an identical and independent way in each round of the protocol.
This is achieved by leveraging the sequential nature of the protocol, and makes
use of a newly developed tool, the "entropy accumulation theorem" of Dupuis et
al.
  As concrete applications we give simple and modular security proofs for
device-independent quantum key distribution and randomness expansion protocols
based on the CHSH inequality. For both tasks we establish essentially optimal
asymptotic key rates and noise tolerance. In view of recent experimental
progress, which has culminated in loophole-free Bell tests, it is likely that
these protocols can be practically implemented in the near future.


title: Dark matter and observable Lepton Flavour Violation

abstract:
  Seesaw models with leptonic symmetries allow right-handed (RH) neutrino
masses at the electroweak scale, or even lower, at the same time having large
Yukawa couplings with the Standard Model leptons, thus yielding observable
effects at current or near-future lepton-flavour-violation (LFV) experiments.
These models have been previously considered also in connection to low-scale
leptogenesis, but the combination of observable LFV and successful leptogenesis
has appeared to be difficult to achieve unless the leptonic symmetry is
embedded into a larger one. In this paper, instead, we follow a different route
and consider a possible connection between large LFV rates and Dark Matter
(DM). We present a model in which the same leptonic symmetry responsible for
the large Yukawa couplings guarantees the stability of the DM candidate,
identified as the lightest of the RH neutrinos. The spontaneous breaking of
this symmetry, caused by a Majoron-like field, also provides a mechanism to
produce the observed relic density via the decays of the latter. The
phenomenological implications of the model are discussed, finding that large
LFV rates, observable in the near-future $\mu \to e$ conversion experiments,
require the DM mass to be in the keV range. Moreover, the active-neutrino
coupling to the Majoron-like scalar field could be probed in future detections
of supernova neutrino bursts.


title:
Measurement of the scalar polarizability of the indium $6p_{1/2}$ state
  using two-step atomic-beam spectroscopy

abstract:
  We have completed a measurement of the Stark shift within the $^{115}$In
$6s_{1/2} \rightarrow 6p_{1/2}$ excited-state transition using two-step laser
spectroscopy in an indium atomic beam. Combining this measurement with recent
experimental results we determine the scalar polarizability, $\alpha_{0}$, of
the $6p_{1/2}$ state to be $7683 \pm43 \,a_{0}^{3}$ in atomic units, a result
which agrees very well with recent theoretical calculations. In this
experiment, one laser, stabilized to the $5p_{1/2} \rightarrow 6s_{1/2}$ 410~nm
transition, was directed transversely to the atomic beam, while a second,
overlapping laser was scanned across the 1343~nm $6s_{1/2} \rightarrow
6p_{1/2}$ transition. We utilized two-tone frequency-modulation spectroscopy of
the infrared laser beam to measure the second-step absorption in the
interaction region, where the optical depth is less than 10$^{-3}$. In the
course of our experimental work we also determined the hyperfine splitting
within the $6p_{1/2}$ state, improving upon the precision of an existing
measurement.


title:
A statistical investigation of the mass discrepancy-acceleration
  relation

abstract:
  We use the mass discrepancy-acceleration relation (the correlation between
the ratio of total-to-visible mass and acceleration in galaxies; MDAR) to test
the galaxy-halo connection. We analyse the MDAR using a set of 16 statistics
that quantify its four most important features: its shape, its scatter, the
presence of a "characteristic acceleration scale," and the correlation of its
residuals with other galaxy properties. We construct an empirical framework for
the galaxy-halo connection in LCDM to generate predictions for these
statistics, starting with conventional correlations (halo abundance matching;
AM) and introducing more where required. Comparing to the SPARC data, we find
that: 1) the approximate shape of the MDAR is readily reproduced by AM, and
there is no evidence that the acceleration at which dark matter becomes
negligible has less spread in the data than in AM mocks; 2) even under
conservative assumptions, AM significantly overpredicts the scatter in the
relation and its normalisation at low acceleration, and furthermore positions
dark matter too close to galaxies' centres on average; 3) the MDAR affords 2
sigma evidence for an anticorrelation of galaxy size and Hubble type with halo
mass or concentration at fixed stellar mass. Our analysis lays the groundwork
for a bottom-up determination of the galaxy-halo connection from relations such
as the MDAR, provides concrete statistical tests for specific galaxy formation
models, and brings into sharper focus the relative evidence accorded by galaxy
kinematics to LCDM and modified gravity alternatives.


title: Interferometric Approach to Probing Fast Scrambling

abstract:
  Out-of-time-order correlation functions provide a proxy for diagnosing chaos
in quantum systems. We propose and analyze an interferometric scheme for their
measurement, using only local quantum control and no reverse time evolution.
Our approach utilizes a combination of Ramsey interferometry and the recently
demonstrated ability to directly measure Renyi entropies. To implement our
scheme, we present a pair of cold-atom-based experimental blueprints; moreover,
we demonstrate that within these systems, one can naturally realize the
transverse-field Sherrington-Kirkpatrick (TFSK) model, which exhibits certain
similarities with fast scrambling black holes. We perform a detailed numerical
study of scrambling in the TFSK model, observing an interesting interplay
between the fast scrambling bound and the onset of spin-glass order.

categories: quant-ph cond-mat.dis-nn cond-mat.quant-gas cond-mat.stat-mech hep-th


title:
Hybrid Adaptive Ray-Moment Method (HARM$^2$): A Highly Parallel Method
  for Radiation Hydrodynamics on Adaptive Grids

abstract:
  We present a highly-parallel multi-frequency hybrid radiation hydrodynamics
algorithm that combines a spatially-adaptive long characteristics method for
the radiation field from point sources with a moment method that handles the
diffuse radiation field produced by a volume-filling fluid. Our Hybrid Adaptive
Ray-Moment Method (HARM$^2$) operates on patch-based adaptive grids, is
compatible with asynchronous time stepping, and works with any moment method.
In comparison to previous long characteristics methods, we have greatly
improved the parallel performance of the adaptive long-characteristics method
by developing a new completely asynchronous and non-blocking communication
algorithm. As a result of this improvement, our implementation achieves
near-perfect scaling up to $\mathcal{O}(10^3)$ processors on distributed memory
machines. We present a series of tests to demonstrate the accuracy and
performance of the method.


title:
Multi-phase induced inflation in theories with non-minimal coupling to
  gravity

abstract:
  In this paper we investigate the induced inflation with two flat regions: one
Starobinsky-like plateau in big field regime and one shorter plateau around the
saddle point of the Einstein frame potential. This multi-phase inflationary
scenario can be used to solve the problem of classical cosmology. The inflation
at the saddle-point plateau is consistent with the data and can have
arbitrarily low scale. The results can be useful in the context of the
Higgs-Axion relaxation and in a certain limit they are equivalent to the
$\alpha$-attractors.


title:
A Motivated Rendition of the Ellenberg-Gijswijt Gorgeous proof that the
  Largest Subset of $F_3^n$ with No Three-Term Arithmetic Progression is
  $O(c^n)$, with $c=\root 3 \of {(5589+891\,\sqrt
  {33})}/8=2.75510461302363300022127...$

abstract:
  Inspired by the Croot-Lev-Pach breakthrough, Jordan Ellenberg and Dion
Gijswijt have recently amazed the combinatorial world by proving that the
largest size of a subset of $F_3^n$ with no 3-term arithmetic progressions is
exponentially less than the size, $3^n$ of $F_3^n$ (and, more generally, $q^n$
for $F_q^n$). Here we give a motivated, top-down, rendition of their beautiful
proof, that aims to make it appreciated by a wider audience.


title: Chirality of topological gap solitons in bosonic dimer chains

abstract:
  We study gap solitons which appear in the topological gap of 1D bosonic dimer
chains within the mean-field approximation. We find that such solitons have a
non-trivial texture of the sublattice pseudospin. We reveal their chiral nature
by demonstrating the anisotropy of their behavior in presence of a localized
energy potential.


title:
Instability in interacting dark sector: An appropriate Holographic Ricci
  dark energy model

abstract:
  In this paper we investigate the consequences of phantom crossing considering
the perturbative dynamics in models with interaction in their dark sector. By
mean of a general study of gauge-invariant variables in comoving gauge, we
relate the sources of instabilities in the structure formation process with the
phantom crossing. In order to illustrate these relations and its consequences
in more detail, we consider a specific case of an holographic dark energy
interacting with dark matter. We find that in spite of the model is in
excellent agreement with observational data at background level, however it is
plagued of instabilities in its perturbative dynamics. We reconstruct the model
in order to avoid these undesirable instabilities, and we show that this
implies a modification of the concordance model at background. Also we find
drastic changes on the parameters space in our model when instabilities are
avoided.


title: Holographic Magnetisation Density Waves

abstract:
  We numerically construct asymptotically $AdS$ black brane solutions of $D=4$
Einstein theory coupled to a scalar and two $U(1)$ gauge fields. The solutions
are holographically dual to $d=3$ CFTs in a constant external magnetic field
along one of the $U(1)$'s. Below a critical temperature the system's
magnetisation density becomes inhomogeneous, leading to spontaneous formation
of current density waves. We find that the transition can be of second order
and that the solutions which minimise the free energy locally in the parameter
space of solutions have averaged stressed tensor of a perfect fluid.


title: The Quantum Prediction for Einstein-Podolsky-Rosen (EPR) Experiments

abstract:
  Quantum mechanics allows for multiple predictions for the outcome of an EPR
experiment. The correct calculation must be used, guided by the physical
conditions of the experiment. The quantum joint prediction for EPR correlation
is derived and shown to involve a single sampling. The solution for separated
measurement, where there are two private samplings, is then developed using
orthodox quantum mechanics with Luders' rule for state projection on
measurement. The separated solution is shown to duplicate the predictions of
the quantum joint solution. However, it is shown that this solution requires
superluminal transmission of information and therefore it is physically
impossible. Alternative predictions respecting special relativity are developed
using both Von Neumann projection and null projection (no projection at all).
Conditions for the proper application of state projection rules are considered
and Luders' rule is identified as the primary culprit in the EPR paradox. It
cannot be applied to EPR.