title:
Testing LSST Dither Strategies for Survey Uniformity and Large-Scale
  Structure Systematics

abstract:
  The Large Synoptic Survey Telescope (LSST) will survey the southern sky from
2022--2032 with unprecedented detail. Since the observing strategy can lead to
artifacts in the data, we investigate the effects of telescope-pointing offsets
(called dithers) on the $r$-band coadded 5$\sigma$ depth yielded after the
10-year survey. We analyze this survey depth for several geometric patterns of
dithers (e.g., random, hexagonal lattice, spiral) with amplitude as large as
the radius of the LSST field-of-view, implemented on different timescales (per
season, per night, per visit). Our results illustrate that per night and per
visit dither assignments are more effective than per season. Also, we find that
some dither geometries (e.g., hexagonal lattice) are particularly sensitive to
the timescale on which the dithers are implemented, while others like random
dithers perform well on all timescales. We then model the propagation of depth
variations to artificial fluctuations in galaxy counts, which are a systematic
for large-scale structure studies. We calculate the bias in galaxy counts
caused by the observing strategy, accounting for photometric calibration
uncertainties, dust extinction, and magnitude cuts; uncertainties in this bias
limit our ability to account for structure induced by the observing strategy.
We find that after 10 years of the LSST survey, the best dither strategies lead
to uncertainties in this bias smaller than the minimum statistical floor for a
galaxy catalog as deep as $r$$<$27.5. A few of these strategies bring the
uncertainties close to the statistical floor for $r$$<$25.7 after only one year
of survey.


title: Front propagation into unstable states in discrete media

abstract:
  Non-equilibrium dissipative systems usually exhibit multistability, leading
to the presence of propagative domain between steady states. We investigate the
front propagation into an unstable state in discrete media. Based on a
paradigmatic model of coupled chain of oscillators and populations dynamics, we
calculate analytically the average speed of these fronts and characterize
numerically the oscillatory front propagation. We reveal that different parts
of the front oscillate with the same frequency but with different amplitude. To
describe this latter phenomenon we generalize the notion of the Peierls-Nabarro
potential, achieving an effective continuous description of the discreteness
effect.


title: Strangeness in nuclear physics

abstract:
  Extensions of nuclear physics to the strange sector are reviewed, covering
data and models of Lambda and other hypernuclei, multi-strange matter, and
anti-kaon bound states and condensation. Past achievements are highlighted,
present unresolved problems discussed, and future directions outlined.


title:
Algorithms for the Pagination Problem, a Bin Packing with Overlapping
  Items

abstract:
  We introduce the strongly NP-complete pagination problem, an extension of BIN
PACKING where packing together two items may make them occupy less volume than
the sum of their individual sizes. To achieve this property, an item is defined
as a finite set of symbols from a given alphabet: while, in BIN PACKING, any
two such sets would be disjoint, in PAGINATION, they can share zero, one or
more symbols. After formulating the problem as an integer linear program, we
try to approximate its solutions with several families of algorithms: from
straightforward adaptations of classical BIN PACKING heuristics, to dedicated
algorithms (greedy and non-greedy), to standard and grouping genetic
algorithms. All of them are studied first theoretically, then experimentally on
an extensive random test set. Based upon these data, we propose a predictive
measure of the statistical difficulty of a given instance, and finally
recommend which algorithm should be used in which case, depending on either
time constraints or quality requirements.


title: Age-of-Information in the Presence of Error

abstract:
  We consider the peak age-of-information (PAoI) in an M/M/1 queueing system
with packet delivery error, i.e., update packets can get lost during
transmissions to their destination. We focus on two types of policies, one is
to adopt Last-Come-First-Served (LCFS) scheduling, and the other is to utilize
retransmissions, i.e., keep transmitting the most recent packet. Both policies
can effectively avoid the queueing delay of a busy channel and ensure a small
PAoI. Exact PAoI expressions under both policies with different error
probabilities are derived, including First-Come-First-Served (FCFS), LCFS with
preemptive priority, LCFS with non-preemptive priority, Retransmission with
preemptive priority, and Retransmission with non-preemptive priority. Numerical
results obtained from analysis and simulation are presented to validate our
results.


title: Finite dimensional Hopf actions on algebraic quantizations

abstract:
  Let k be an algebraically closed field of characteristic zero. In joint work
with J. Cuadra [arxiv.org/abs/1409.1644, arxiv.org/abs/1509.01165], we showed
that a semisimple Hopf action on a Weyl algebra over a polynomial algebra
k[z_1,...,z_s] factors through a group action, and this in fact holds for any
finite dimensional Hopf action if s=0. We also generalized these results to
finite dimensional Hopf actions on algebras of differential operators. In this
work we establish similar results for Hopf actions on other algebraic
quantizations of commutative domains. This includes universal enveloping
algebras of finite dimensional Lie algebras, spherical symplectic reflection
algebras, quantum Hamiltonian reductions of Weyl algebras (in particular,
quantized quiver varieties), finite W-algebras and their central reductions,
quantum polynomial algebras, twisted homogeneous coordinate rings of abelian
varieties, and Sklyanin algebras. The generalization in the last three cases
uses a result from algebraic number theory, due to A. Perucca.


title: Parallel Wavelet Schemes for Images

abstract:
  In this paper, we introduce several new schemes for calculation of discrete
wavelet transforms of images. These schemes reduce the number of steps and, as
a consequence, allow to reduce the number of synchronizations on parallel
architectures. As an additional useful property, the proposed schemes can
reduce also the number of arithmetic operations. The schemes are primarily
demonstrated on CDF 5/3 and CDF 9/7 wavelets employed in JPEG 2000 image
compression standard. However, the presented method is general, and it can be
applied on any wavelet transform. As a result, our scheme requires only two
memory barriers for 2-D CDF 5/3 transform compared to four barriers in the
original separable form or three barriers in the non-separable scheme recently
published. Our reasoning is supported by exhaustive experiments on high-end
graphics cards.


title:
Persistent homology of time-dependent functional networks constructed
  from coupled time series

abstract:
  We use topological data analysis to study "functional networks" that we
construct from time-series data from both experimental and synthetic sources.
We use persistent homology with a weight rank clique filtration to gain
insights into these functional networks, and we use persistence landscapes to
interpret our results. Our first example uses time-series output from networks
of coupled Kuramoto oscillators. Our second example consists of biological data
in the form of functional magnetic resonance imaging (fMRI) data that was
acquired from human subjects during a simple motor-learning task in which
subjects were monitored on three days in a five-day period. With these
examples, we demonstrate that (1) using persistent homology to study functional
networks provides fascinating insights into their properties and (2) the
position of the features in a filtration can sometimes play a more vital role
than persistence in the interpretation of topological features, even though
conventionally the latter is used to distinguish between signal and noise. We
find that persistent homology can detect differences in synchronization
patterns in our data sets over time, giving insight both on changes in
community structure in the networks and on increased synchronization between
brain regions that form loops in a functional network during motor learning.
For the motor-learning data, persistence landscapes also reveal that on average
the majority of changes in the network loops take place on the second of the
three days of the learning process.

categories: q-bio.QM cond-mat.dis-nn math.AT nlin.AO q-bio.NC


title:
Exceptional generalised geometry for massive IIA and consistent
  reductions

abstract:
  We develop an exceptional generalised geometry formalism for massive type IIA
supergravity. In particular, we construct a deformation of the generalised Lie
derivative, which generates the type IIA gauge transformations as modified by
the Romans mass. We apply this new framework to consistent Kaluza-Klein
reductions preserving maximal supersymmetry. We find a generalised
parallelisation of the exceptional tangent bundle on S^6, and from this
reproduce the consistent truncation ansatz and embedding tensor leading to
dyonically gauged ISO(7) supergravity in four dimensions. We also discuss
closely related hyperboloid reductions, yielding a dyonic ISO(p,7-p) gauging.
Finally, while for vanishing Romans mass we find a generalised parallelisation
on S^d, d=4,3,2, leading to a maximally supersymmetric reduction with gauge
group SO(d+1) (or larger), we provide evidence that an analogous reduction does
not exist in the massive theory.


title:
Nucleon matrix elements from lattice QCD with all-mode-averaging and a
  domain-decomposed solver: an exploratory study

abstract:
  We study the performance of all-mode-averaging (AMA) when used in conjunction
with a locally deflated SAP-preconditioned solver, determining how to optimize
the local block sizes and number of deflation fields in order to minimize the
computational cost for a given level of overall statistical accuracy. We find
that AMA enables a reduction of the statistical error on nucleon charges by a
factor of around two at the same cost when compared to the standard method. As
a demonstration, we compute the axial, scalar and tensor charges of the nucleon
in $N_f=2$ lattice QCD with non-perturbatively O(a)-improved Wilson quarks,
using O(10,000) measurements to pursue the signal out to source-sink
separations of $t_s\sim 1.5$ fm. Our results suggest that the axial charge is
suffering from a significant amount (5-10%) of excited-state contamination at
source-sink separations of up to $t_s\sim 1.2$ fm, whereas the excited-state
contamination in the scalar and tensor charges seems to be small.


title: Weaker consistency notions for all the CSPs of bounded width

abstract:
  The characterization of all the Constraint Satisfaction Problems of bounded
width, proposed by Feder and Vardi [SICOMP'98], was confirmed in [Bulatov'09]
and independently in [FOCS'09, JACM'14]. Both proofs are based on the
(2,3)-consistency (using Prague consistency in [FOCS'09], directly in
[Bulatov'09]) which is costly to verify.
  We introduce a new consistency notion, Singleton Linear Arc Consistency
(SLAC), and show that it solves the same family of problems. SLAC is weaker
than Singleton Arc Consistency (SAC) and thus the result answers the question
from [JLC'13] by showing that SAC solves all the problems of bounded width. At
the same time the problem of verifying weaker consistency (even SAC) offers
significant computational advantages over the problem of verifying
(2,3)-consistency which improves the algorithms solving the CSPs of bounded
width.


title: The future's not ours to see

abstract:
  An account of determinism and indeterminism in physics, addressed to
non-physicist readers, leading up to proposals for how to understand statements
about the future and single-event probability, motivated by quantum mechanics.


title:
Evolution of a superfluid vortex filament tangle driven by the
  Gross-Pitaevskii equation

abstract:
  The development and decay of a turbulent vortex tangle driven by the
Gross-Pitaevskii equation is studied. Using a recently-developed accurate and
robust tracking algorithm, all quantised vortices are extracted from the
fields. The Vinen's decay law for the total vortex length with a coefficient
that is in quantitative agreement with the values measured in Helium II is
observed. The topology of the tangle is then studied showing that linked rings
may appear during the decay. The tracking also allows for determining the
statistics of small-scales quantities of vortex lines, exhibiting large
fluctuations of curvature and torsion. Finally, the temporal evolution of the
Kelvin wave spectrum is obtained providing evidence of the development of a
weak-wave turbulence cascade.


title:
A Lagrangian scheme for the incompressible Euler equation using optimal
  transport

abstract:
  We approximate the regular solutions of the incompressible Euler equation by
the solution of ODEs on finite-dimensional spaces. Our approach combines
Arnold's interpretation of the solution of Euler's equation for incompressible
and inviscid fluids as geodesics in the space of measure-preserving
diffeomorphisms, and an extrinsic approximation of the equations of geodesics
due to Brenier. Using recently developed semi-discrete optimal transport
solvers, this approach yields numerical scheme able to handle problems of
realistic size in 2D. Our purpose in this article is to establish the
convergence of these scheme towards regular solutions of the incompressible
Euler equation, and to provide numerical experiments on a few simple testcases
in 2D.


title: Lorentz invariant relative velocity and relativistic binary collisions

abstract:
  This article reviews the concept of Lorentz invariant relative velocity that
is often misunderstood or unknown in high energy physics literature. The
properties of the relative velocity allow to formulate the invariant flux and
cross section without recurring to non--physical velocities or any assumption
about the reference frame. Applications such as the luminosity of a collider,
the use as kinematic variable, and the statistical theory of collisions in a
relativistic classical gas are reviewed. It is emphasized how the hyperbolic
properties of the velocity space explain the peculiarities of relativistic
scattering.


title:
Holographic duality between $(2+1)$-d quantum anomalous Hall state and
  $(3+1)$-d topological insulators

abstract:
  In this paper, we study $(2+1)$-dimensional quantum anomalous Hall states,
i.e. band insulators with quantized Hall conductance, using the exact
holographic mapping. The exact holographic mapping is an approach to
holographic duality which maps the quantum anomalous Hall state to a different
state living in $(3+1)$-dimensional hyperbolic space. By studying topological
response properties and the entanglement spectrum, we demonstrate that the
holographic dual theory of a quantum anomalous Hall state is a
$(3+1)$-dimensional topological insulator. The dual description enables a new
characterization of topological properties of a system by the quantum
entanglement between degrees of freedom at different length scales.

categories: cond-mat.mes-hall cond-mat.str-el hep-th quant-ph


title:
The GeV counterpart of VER J2019+407 in the northern shell of the
  supernova remnant G78.2+2.1 ($\gamma$ Cygni)

abstract:
  Analysis of gamma-ray emission from the supernova remnant G78.2+2.1 ($\gamma$
Cygni) with 7.2 years of cumulative data from the Fermi-LAT telescope shows a
distinct hard, bright and extended component to the north of the shell
coincident with the known TeV source VER J2019+407. In the GeV-TeV energy range
its spectrum is best described by a broken power-law with indices 1.8 below a
break energy of 71 GeV and 2.5 above the break. A broadband spectral energy
distribution is assembled and different scenarios for the origin of the
gamma-rays are explored. Both hadronic and leptonic mechanisms are able to
account for the GeV-TeV observations. In the leptonic framework, a
superposition of inverse Compton and nonthermal bremsstrahlung emissions is
needed whereas the hadronic scenario requires a cosmic ray population described
by a broken power-law distribution with a relatively hard spectral index of
$\sim1.8$ below a break particle energy of 0.45 TeV. In addition, the neutrino
flux expected from cosmic ray interactions is calculated.


title: Comparison of Optimization Methods in Optical Flow Estimation

abstract:
  Optical flow estimation is a widely known problem in computer vision
introduced by Gibson, J.J(1950) to describe the visual perception of human by
stimulus objects. Estimation of optical flow model can be achieved by solving
for the motion vectors from region of interest in the the different timeline.
In this paper, we assumed slightly uniform change of velocity between two
nearby frames, and solve the optical flow problem by traditional method,
Lucas-Kanade(1981). This method performs minimization of errors between
template and target frame warped back onto the template. Solving minimization
steps requires optimization methods which have diverse convergence rate and
error. We explored first and second order optimization methods, and compare
their results with Gauss-Newton method in Lucas-Kanade. We generated 105 videos
with 10,500 frames by synthetic objects, and 10 videos with 1,000 frames from
real world footage. Our experimental results could be used as tuning parameters
for Lucas-Kanade method.


title: Effective Field Theories for the LHC

abstract:
  In this thesis I study applications of effective field theories to understand
aspects of QCD jets and their substructure at the Large Hadron Collider. In
particular, I introduce an observable, $D_2$, which can be used for
distinguishing boosted $W/Z/H$ bosons from the QCD background using information
about the radiation pattern within the jet, and perform a precision calculation
of this observable. To simplify calculations in the soft collinear effective
theory, I also develop a helicity operator basis, which facilitates matching
calculations to fixed order computations performed using spinor-helicity
techniques, and demonstrate its utility by computing an observable relevant for
studying the properties of the newly discovered Higgs boson.


title: Variational estimates for the bilinear iterated Fourier integral

abstract:
  We prove pointwise variational Lp bounds for a bilinear Fourier integral
operator in a large but not necessarily sharp range of exponents. This result
is a joint strengthening of the corresponding bounds for the classical Carleson
operator, the bilinear Hilbert transform, the variation norm Carleson operator,
and the bi-Carleson operator. Terry Lyon's rough path theory allows for
extension of our result to multilinear estimates. We consider our result a
proof of concept for a wider array of similar estimates with possible
applications to ordinary differential equations.


title:
Flipped versions of the universal 3-3-1 and the left-right symmetric
  models in $[SU(3)]^3$: a comprehensive approach

abstract:
  By considering the 3-3-1 and the left-right symmetric models as low energy
effective theories of the $SU(3)_C\otimes SU(3)_L\otimes SU(3)_R$~(for short
$[SU(3)]^3$) gauge group, alternative versions of these models are found. The
new neutral gauge bosons of the universal 3-3-1 model and its flipped versions
are presented; also, the left-right symmetric model and its flipped variants
are studied. Our analysis shows that there are two flipped versions of the
universal 3-3-1 model, with the particularity that both of them have the same
weak charges. For the left-right symmetric model we also found two flipped
versions; one of them new in the literature which, unlike those of the 3-3-1,
requires a dedicated study of its electroweak properties. For all the models
analyzed, the couplings of the $Z'$ bosons to the standard model fermions are
reported. The explicit form of the null space of the vector boson mass matrix
for an arbitrary Higgs tensor and gauge group is also presented. In the general
framework of the $[SU(3)]^3$ gauge group, and by using the LHC experimental
results and EW precision data, limits on the $Z'$ mass and the mixing angle
between $Z$ and the new gauge bosons $Z'$ are obtained. The general results
call for very small mixing angles in the range $10^{-3}$ radians and $M_{Z'}>$
2.5 TeV.


title:
Nonlinear heat conduction equations with memory: physical meaning and
  analytical results

abstract:
  We study nonlinear heat conduction equations with memory effects within the
framework of the fractional calculus approach to the generalized
Maxwell-Cattaneo law. Our main aim is to derive the governing equations of heat
propagation, considering both the empirical temperature-dependence of the
thermal conductivity coefficient (which introduces nonlinearity) and memory
effects, according to the general theory of Gurtin and Pipkin of finite
velocity thermal propagation with memory. In this framework, we consider in
detail two different approaches to the generalized Maxwell-Cattaneo law, based
on the application of long-tail Mittag-Leffler memory function and power law
relaxation functions, leading to nonlinear time-fractional telegraph and
wave-type equations. We also discuss some explicit analytical results to the
model equations based on the generalized separating variable method and discuss
their meaning in relation to some well-known results of the ordinary case.


title:
Notes on exploded manifolds and a tropical gluing formula for
  Gromov-WItten invariants

abstract:
  Notes for a short lecture series, covering exploded manifolds, the moduli
stack of curves in exploded manifolds, and a tropical gluing formula for
Gromov-Witten invariants: a gluing formula providing a degeneration formula for
Gromov-Witten invariants in normal-crossing degenerations. I gave the original
lecture series in April 2016 at the Simons Center for Geometry and Physics at
Stonybrook. Video of the lectures is available on the SCGP website,
http://scgp.stonybrook.edu/video_portal/video.php?id=2595


title: Neutrinos in Astrophysics and Cosmology

abstract:
  Neutrinos play a crucial role in many aspects of astrophysics and cosmology.
Since they control the electron fraction, or equivalently neutron-to-proton
ratio, neutrino properties impact yields of r-process nucleosynthesis.
Similarly the weak decoupling temperature in the Big Bang Nucleosynthesis epoch
is exponentially dependent on the neutron-to-proton ratio. In these conference
proceedings, I briefly summarize some of the recent work exploring the role of
neutrinos in astrophysics and cosmology.


title: THEO Concept Mission: Testing the Habitability of Enceladus's Ocean

abstract:
  Saturn's moon Enceladus offers a unique opportunity in the search for life
and habitable environments beyond Earth, a key theme of the National Research
Council's 2013-2022 Decadal Survey. A plume of water vapor and ice spews from
Enceladus's south polar region. Cassini data suggest that this plume, sourced
by a liquid reservoir beneath the moon's icy crust, contain organics, salts,
and water-rock interaction derivatives. Thus, the ingredients for life as we
know it-- liquid water, chemistry, and energy sources-- are available in
Enceladus's subsurface ocean. We have only to sample the plumes to investigate
this hidden ocean environment. We present a New Frontiers class, solar-powered
Enceladus orbiter that would take advantage of this opportunity, Testing the
Habitability of Enceladus's Ocean (THEO). Developed by the 2015 Jet Propulsion
Laboratory Planetary Science Summer School student participants under the
guidance of TeamX, this mission concept includes remote sensing and in situ
analyses with a mass spectrometer, a sub-mm radiometer-spectrometer, a camera,
and two magnetometers. These instruments were selected to address four key
questions for ascertaining the habitability of Enceladus's ocean within the
context of the moon's geological activity: (1) How are the plumes and ocean
connected? (2) Are the abiotic conditions of the ocean suitable for
habitability? (3) How stable is the ocean environment? (4) Is there evidence of
biological processes? By taking advantage of the opportunity Enceladus's plumes
offer, THEO represents a viable, solar-powered option for exploring a
potentially habitable ocean world of the outer solar system.


title:
A computational scheme to evaluate Hamaker constants of molecules with
  practical size and anisotropy

abstract:
  We propose a computational scheme to evaluate Hamaker constants, $A$, of
molecules with practical sizes and anisotropies. Upon the increasing
feasibility of diffusion Monte Carlo (DMC) methods to evaluate binding curves
for such molecules to extract the constants, we discussed how to treat the
averaging over anisotropy and how to correct the bias due to the
non-additivity. We have developed a computational procedure for dealing with
the anisotropy and reducing statistical errors and biases in DMC valuations,
based on possible validations on predicted $A$. We applied the scheme to
cyclohexasilane molecule, Si$_6$H$_{12}$, used in 'printed electronics'
fabrications, getting $A \sim 105 \pm 2$ [zJ], being in plausible range
supported even by other possible extrapolations. The scheme provided here would
open a way to use handy {\it ab initio} evaluations to predict wettabilities as
in the form of materials informatics over broader molecules.


title:
Martingales in self-similar growth-fragmentations and their connections
  with random planar maps

abstract:
  The purpose of the present work is twofold. First, we develop the theory of
general self-similar growth-fragmentation processes by focusing on martingales
which appear naturally in this setting and by recasting classical results for
branching random walks in this framework. In particular, we establish
many-to-one formulas for growth-fragmentations and define the notion of
intrinsic area of a growth-fragmentation. Second, we identify a distinguished
family of growth-fragmentations closely related to stable L\'evy processes,
which are then shown to arise as the scaling limit of the perimeter process in
Markovian explorations of certain random planar maps with large degrees (which
are, roughly speaking, the dual maps of the stable maps of Le Gall & Miermont.
As a consequence of this result, we are able to identify the law of the
intrinsic area of these distinguished growth-fragmentations. This generalizes a
geometric connection between large Boltzmann triangulations and a certain
growth-fragmentation process, which was established in arXiv:1507.02265 .


title: The effect of polarization entanglement in photon-photon scattering

abstract:
  It is found that the differential cross section of photon-photon scattering
is a function of the degree of polarization entanglement of the two-photon
state. A reduced, general expression for the differential cross section of
photon-photon scattering is derived by applying simple symmetry arguments. An
explicit expression is obtained for the example of photon-photon scattering due
to virtual electron-positron pairs in Quantum Electrodynamics. It is shown how
the effect in this explicit example can be explained as an effect of quantum
interference and that it fits with the idea of distance-dependent forces.


title: A Note on Schwarzschild de Sitter Black Holes in Mimetic $F(R)$ Gravity

abstract:
  In this brief note we investigate the conditions under which a Schwarzschild
de Sitter black hole spacetime is a solution of the mimetic $F(R)$ gravity with
Lagrange multiplier and potential. As we demonstrate, the resulting mimetic
$F(R)$ gravity is a slight modification of the ordinary $F(R)$ gravity case,
however the resulting perturbation equations are not in all cases identical to
the ordinary $F(R)$ gravity case. In the latter case, the perturbation
equations are identical to the ones corresponding to the Reissner-Nordstr\"{o}m
anti-de Sitter black hole.


title: Dynamics of Discrete Time Systems with a Hysteresis Stop Operator

abstract:
  We consider a piecewise linear two-dimensional dynamical system that couples
a linear equation with the so-called stop operator. Global dynamics and
bifurcations of this system are studied depending on two parameters. The system
is motivated by modifications to general-equilibrium macroeconomic models that
attempt to capture the frictions and memory-dependence of realistic economic
agents.


title: Probing gaugino coannihilation with displaced vertex searches

abstract:
  Bino-like dark matter in supersymmetric theories tends to suffer from
over-production. This problem can be evaded if there is another gaugino which
has a mass close to the bino mass so that it enhances the annihilation rate of
bino dark matter through coannihilation. We study such possibilities in
high-scale supersymmetric models, and show that searches for long-lived
particles with displaced vertices can test the bino-gaugino coannihilation
scenario in the forthcoming LHC experiments.


title:
Stabilizing the Hexagonal Close Packed Structure of Hard Spheres with
  Polymers : Phase diagram, Structure, and Dynamics

abstract:
  We study the phase behaviour of a binary mixture of colloidal hard spheres
and freely-jointed chains of beads using Monte Carlo simulations. Recently
Panagiotopoulos and coworkers predicted [Nat. Commun. 5, 4472 (2014)] that the
hexagonal close packed (HCP) structure of hard spheres can be stabilized in
such a mixture due to the interplay between polymer and the void structure in
the crystal phase. Their predictions were based on estimates of the free-energy
penalty for adding a single hard polymer chain in the HCP and the competing
face centered cubic (FCC) phase. Here we calculate the phase diagram using
free-energy calculations of the full binary mixture and find a broad
fluid-solid coexistence region and a metastable gas-liquid coexistence region.
For the colloid-monomer size ratio considered in this work, we find that the
HCP phase is only stable in a small window at relatively high polymer reservoir
packing fractions, where the coexisting HCP phase is nearly close packed.
Additionally we investigate the structure and dynamic behaviour of these
mixtures.


title: A Lefschetz (1,1) theorem for singular varieties

abstract:
  The goal of this article is to try understand where Hodge cycles on a
singular complex projective variety X come from. As a first step we consider
Hodge cycles on the maximal pure quotient $H^{2p}(X)/W_{2p-1}$, and introduce a
class of algebraic cycles that we call homologically Cartier, that should
conjecturally describe all such Hodge cycles. Secondly, given a singular
complex projective variety $X$, we show that there is a cycle map from motivic
cohomology group $H^{2p}_M(X,Q(p))$ to the space of weight 2p Hodge cycles in
$H^{2p}(X,Q)$. We conjecture that this is surjective when X is defined over the
algebraic closure of $\mathbb{Q}$. We show that this holds integrally when p=1,
and we also give a concrete interpretation of motivic classes in this degree.
Finally, we show that the general conjecture holds for a self fibre product of
elliptic modular surfaces.


title: Discretising the Herman--Kluk Propagator

abstract:
  The Herman--Kluk propagator is a popular semi-classical approximation of the
unitary evolution operator in quantum molecular dynamics. In this paper we
formulate the Herman--Kluk propagator as a phase space integral and discretise
it by Monte Carlo and quasi-Monte Carlo quadrature. Then, we investigate the
accuracy of a symplectic time discretisation by combining backward error
analysis with Fourier integral operator calculus. Numerical experiments for
two- and six-dimensional model systems support our theoretical results.


title:
The propagation of chaos for a rarefied gas of hard spheres in the whole
  space

abstract:
  We discuss old and new results on the mathematical justification of
Boltzmann's equation. The classical result along these lines is a theorem which
was proven by Lanford in the 1970s. This paper is naturally divided into three
parts.
  I. Classical. We give new proofs of both the uniform bounds required for
Lanford's theorem, as well as the related bounds due to Illner & Pulvirenti for
a perturbation of vacuum. The proofs use a duality argument and differential
inequalities, instead of a fixed point iteration.
  II. Strong chaos. We introduce a new notion of propagation of chaos. Our
notion of chaos provides for uniform error estimates on a very precise set of
points; this set is closely related to the notion of strong (one-sided) chaos
and the emergence of irreversibility.
  III. Supplemental. We announce and provide a proof (in Appendix A) of
propagation of partial factorization at some phase-points where complete
factorization is impossible.


title:
Performance of the finite volume method in solving regularised Bingham
  flows: inertia effects in the lid-driven cavity flow

abstract:
  We extend our recent work on the creeping flow of a Bingham fluid in a
lid-driven cavity, to the study of inertial effects, using a finite volume
method and the Papanastasiou regularisation of the Bingham constitutive model
[J. Rheology 31 (1987) 385-404]. The finite volume method used belongs to a
very popular class of methods for solving Newtonian flow problems, which use
the SIMPLE algorithm to solve the discretised set of equations, and have
matured over the years. By regularising the Bingham constitutive equation it is
easy to extend such a solver to Bingham flows since all that this requires is
to modify the viscosity function. This is a tempting approach, since it
requires minimum programming effort and makes available all the existing
features of the mature finite volume solver. On the other hand, regularisation
introduces a parameter which controls the error in addition to the grid
spacing, and makes it difficult to locate the yield surfaces. Furthermore, the
equations become stiffer and more difficult to solve, while the discontinuity
at the yield surfaces causes large truncation errors. The present work attempts
to investigate the strengths and weaknesses of such a method by applying it to
the lid-driven cavity problem for a range of Bingham and Reynolds numbers (up
to 100 and 5000 respectively). By employing techniques such as multigrid, local
grid refinement, and an extrapolation procedure to reduce the effect of the
regularisation parameter on the calculation of the yield surfaces (Liu et al.
J. Non-Newtonian Fluid Mech. 102 (2002) 179-191), satisfactory results are
obtained, although the weaknesses of the method become more noticeable as the
Bingham number is increased.


title: The geometry of learning

abstract:
  We establish a correspondence between Pavlovian conditioning processes and
fractals. The association strength at a training trial corresponds to a point
in a disconnected set at a given iteration level. In this way, one can
represent a training process as a hopping on a fractal set, instead of the
traditional learning curve as a function of the trial. The main advantage of
this novel perspective is to provide an elegant classification of associative
theories in terms of the geometric features of fractal sets. In particular, the
dimension of fractals can measure the efficiency of conditioning models. We
illustrate the correspondence with the examples of the Hull, Rescorla-Wagner,
and Mackintosh models and show that they are equivalent to a Cantor set. More
generally, conditioning programs are described by the geometry of their
associated fractal, which gives much more information than just its dimension.
We show this in several examples of random fractals and also comment on a
possible relation between our formalism and other "fractal" findings in the
cognitive literature.


title:
Deformations of symplectic singularities and Orbit method for semisimple
  Lie algebras

abstract:
  We classify filtered quantizations of conical symplectic singularities and
use this to show that all filtered quantizations of symplectic quotient
singularities are spherical Symplectic reflection algebras of Etingof and
Ginzburg. We further apply our classification and a classification of filtered
Poisson deformations obtained by Namikawa to establish a version of the Orbit
method for semisimple Lie algebras. Namely, we produce a natural map from the
set of adjoint orbits in a semisimple Lie algebra to the set of primitive
ideals in the universal enveloping algebra. We show that the map is injective
for classical Lie algebras.


title:
Transient evolution of the global mode in turbulent swirling jets:
  experiments and modal stability analysis

abstract:
  Modal linear stability analysis has proven very successful in the analysis of
coherent structures of turbulent flows. Formally, it describes the evolution of
a disturbance in the limit of infinite time. In this work we apply modal linear
stability analysis to a turbulent swirling jet undergoing a control parameter
transient. The flow undergoes a transition from a non-vortex breakdown state to
a state with a strong recirculation bubble and the associated global mode.
High-speed Particle Image Velocimetry (PIV) measurements are the basis for a
local linear stability analysis of the temporarily evolving base flow. This
analysis reveals that the onset of the global mode is strongly linked to the
formation of the internal stagnation point. Several transition scenarios are
discussed and the ability of a frequency selection criterion to predict the
wavemaker location, frequency and growth rate of the global mode are evaluated.
We find excellent agreement between the linear global mode frequency and the
experimental results throughout the entire transient. The corresponding growth
rate qualitatively conforms to experimental observations. We find no indication
for a nonlinear global mode as proposed by previous studies.


title:
Lattice Gluon and Ghost Propagators, and the Strong Coupling in Pure
  SU(3) Yang-Mills Theory: Finite Lattice Spacing and Volume Effects

abstract:
  The dependence of the Landau gauge two point gluon and ghost correlation
functions on the lattice spacing and on the physical volume are investigated
for pure SU(3) Yang-Mills theory in four dimensions using lattice simulations.
We present data from very large lattices up to $128^4$ and for two lattice
spacings $0.10$ fm and $0.06$ fm corresponding to volumes of $\sim$ (13 fm)$^4$
and $\sim$ (8 fm)$^4$, respectively. Our results show that, for sufficiently
large physical volumes, both propagators have a mild dependence on the lattice
volume. On the other hand, the gluon and ghost propagators change with the
lattice spacing $a$ in the infrared region, with the gluon propagator having a
stronger dependence on $a$ compared to the ghost propagator. In what concerns
the strong coupling constant $\alpha_s (p^2)$, as defined from gluon and ghost
two point functions, the simulations show a sizeable dependence on the lattice
spacing for the infrared region and for momenta up to $\sim 1$ GeV.


title: Holographic entanglement chemistry

abstract:
  We use the Iyer-Wald formalism to derive an extended first law of
entanglement that includes variations in the cosmological constant, Newton's
constant and --in the case of higher-derivative theories-- all the additional
couplings of the theory. In Einstein gravity, where the number of degrees of
freedom $N^2$ of the dual field theory is a function of $\Lambda$ and $G$, our
approach allows us to vary $N$ keeping the field theory scale fixed or to vary
the field theory scale keeping $N$ fixed. We also derive an extended first law
of entanglement for Gauss-Bonnet and Lovelock gravity and show that in these
cases all the extra variations reorganize nicely in terms of the central
charges of the theory. Finally, we comment on the implications for
renormalization group flows and c-theorems in higher dimensions.


title: Graph Clustering Bandits for Recommendation

abstract:
  We investigate an efficient context-dependent clustering technique for
recommender systems based on exploration-exploitation strategies through
multi-armed bandits over multiple users. Our algorithm dynamically groups users
based on their observed behavioral similarity during a sequence of logged
activities. In doing so, the algorithm reacts to the currently served user by
shaping clusters around him/her but, at the same time, it explores the
generation of clusters over users which are not currently engaged. We motivate
the effectiveness of this clustering policy, and provide an extensive empirical
analysis on real-world datasets, showing scalability and improved prediction
performance over state-of-the-art methods for sequential clustering of users in
multi-armed bandit scenarios.


title: Quasi-long-range order in trapped two-dimensional Bose gases

abstract:
  We study the fate of algebraic decay of correlations in a harmonically
trapped two-dimensional degenerate Bose gas. The analysis is inspired by recent
experiments on ultracold atoms where power-law correlations have been observed
despite the presence of the external potential. We generalize the spin wave
description of phase fluctuations to the trapped case and obtain an analytical
expression for the one-body density matrix within this approximation. We show
that algebraic decay of the central correlation function persists to lengths of
about 20% of the Thomas--Fermi radius. We establish that the trap-averaged
correlation function decays algebraically with a strictly larger exponent
weakly changing with trap size and find indications that the recently observed
enhanced scaling exponents receive significant contributions from the normal
component of the gas. We discuss radial and angular correlations and propose a
local correlation approximation which captures the correlations very well. Our
analysis goes beyond the usual local density approximation and the developed
summation techniques constitute a powerful tool to investigate correlations in
inhomogeneous systems.

categories: cond-mat.quant-gas cond-mat.stat-mech hep-ph math-ph math.MP


title: Computational complexity and the conjugacy problem

abstract:
  The conjugacy problem for a finitely generated group $G$ is the two-variable
problem of deciding for an arbitrary pair $(u,v)$ of elements of $G$, whether
or not $u$ is conjugate to $v$ in $G$. We construct examples of finitely
generated, computably presented groups such that for every element $u_0$ of
$G$, the problem of deciding if an arbitrary element is conjugate to $u_0$ is
decidable in quadratic time but the worst-case complexity of the global
conjugacy problem is arbitrary: it can be any c.e. Turing degree , can exactly
mirror the Time Hierarchy Theorem, or can be $\mathcal{NP}$-complete. Our
groups also have the property that the conjugacy problem is generically linear
time: that is, there is a linear time partial algorithm for the conjugacy
problem whose domain has density $1$, so hard instances are very rare. We also
consider the complexity relationship of the "half-conjugacy" problem to the
conjugacy problem. In the last section we discuss the extreme opposite
situation: groups with algorithmically finite conjugation.


title: Dynamics of swelling and drying in a spherical gel

abstract:
  Swelling is a volumetric-growth process in which a porous material expands by
spontaneous imbibition of additional pore fluid. Swelling is distinct from
other growth processes in that it is inherently poromechanical: Local expansion
of the pore structure requires that additional fluid be drawn from elsewhere in
the material, or into the material from across the boundaries. Here, we study
the swelling and subsequent drying of a sphere of hydrogel. We develop a
dynamic model based on large-deformation poromechanics and the theory of ideal
elastomeric gels, and we compare the predictions of this model with a series of
experiments performed with polyacrylamide spheres. We use the model and the
experiments to study the complex internal dynamics of swelling and drying, and
to highlight the fundamentally transient nature of these strikingly different
processes. Although we assume spherical symmetry, the model also provides
insight into the transient patterns that form and then vanish during swelling
as well as the risk of fracture during drying.


title: Spin precession in a black hole and naked singularity spacetimes

abstract:
  We propose here a specific criterion to address the existence or otherwise of
Kerr naked singularities, in terms of the precession of the spin of a test
gyroscope due to the frame dragging by the central spinning body. We show that
there is indeed an important characteristic difference in the behavior of gyro
spin precession frequency in the limit of approach to these compact objects,
and this can be used, in principle, to differentiate the naked singularity from
black hole. Specifically, if gyroscopes are fixed all along the polar axis upto
the horizon of a Kerr black hole, the precession frequency becomes arbitrarily
high, blowing up as the event horizon is approached. On the other hand, in the
case of naked singularity, this frequency remains always finite and
well-behaved. Interestingly, this behavior is intimately related to and is
governed by the geometry of the ergoregion in each of these cases which we
analyze here. One intriguing behavior that emerges is, in the Kerr naked
singularity case, the Lense-Thirring precession frequency ($\Omega_{\rm LT}$)
of the gyroscope due to frame-dragging effect decreases as ($\Omega_{\rm
LT}\propto r$) after reaching a maximum, in the limit of $r= 0$, as opposed to
$r^{-3}$ dependence in all other known astrophysical cases.


title: Distributed Inertial Best-Response Dynamics

abstract:
  The note considers the problem of computing pure Nash equilibrium (NE)
strategies in distributed (i.e., network-based) settings. The paper studies a
class of inertial best response dynamics based on the fictitious play (FP)
algorithm. It is shown that inertial best response dynamics are robust to
informational limitations common in distributed settings. Fully distributed
variants of FP with inertia and joint strategy FP with inertia are developed
and convergence is proven to the set of pure NE. The distributed algorithms
rely on consensus methods. Results are validated using numerical simulations.


title:
An assessment of turbulence models for linear hydrodynamic stability
  analysis of strongly swirling jets

abstract:
  Linear stability analysis has proven to be a useful tool in the analysis of
dominant coherent structures, such as the von K\'{a}rm\'{a}n vortex street and
the global spiral mode associated with the vortex breakdown of swirling jets.
In recent years, linear stability analysis has been applied successfully to
turbulent time-mean flows, instead of laminar base-flows,
\textcolor{black}{which requires turbulent models that account for the
interaction of the turbulent field with the coherent structures. To retain the
stability equations of laminar flows, the Boussinesq approximation with a
spatially nonuniform but isotropic eddy viscosity is typically employed. In
this work we assess the applicability of this concept to turbulent strongly
swirling jets, a class of flows that is particularly unsuited for isotropic
eddy viscosity models. Indeed we find that unsteady RANS simulations only match
with experiments with a Reynolds stress model that accounts for an anisotropic
eddy viscosity. However, linear stability analysis of the mean flow is shown to
accurately predict the global mode growth rate and frequency if the employed
isotropic eddy viscosity represents a least-squares approximation of the
anisotropic eddy viscosity. Viscosities derived from the $k-\epsilon$ model did
not achieve a good prediction of the mean flow nor did they allow for accurate
stability calculations. We conclude from this study that linear stability
analysis can be accurate for flows with strongly anisotropic turbulent
viscosity and the capability of the Boussinesq approximation in terms of
URANS-based mean flow prediction is not a prerequisite.


title: A center vortex representaton of the classical SU(2) vacuum

abstract:
  The classical massless SU(2) field theory has an infinite number of gauge
equivalent representations of the vacuum. We show that among these there exists
a non-perturbative center vortex representation with some similarity to the
quantum vacuum of the same theory. This classical SU(2) vacuum consists of a
lattice of center vortex pairs combining to triviality. However, this
triviality can be broken by perturbations, for example by adding a mass term,
or by considering the electroweak theory where the Higgs field does the
breaking, or by quantum fluctuations like in QCD.


title:
Formal Verification of Obstacle Avoidance and Navigation of Ground
  Robots

abstract:
  The safety of mobile robots in dynamic environments is predicated on making
sure that they do not collide with obstacles. In support of such safety
arguments, we analyze and formally verify a series of increasingly powerful
safety properties of controllers for avoiding both stationary and moving
obstacles: (i) static safety, which ensures that no collisions can happen with
stationary obstacles, (ii) passive safety, which ensures that no collisions can
happen with stationary or moving obstacles while the robot moves, (iii) the
stronger passive friendly safety in which the robot further maintains
sufficient maneuvering distance for obstacles to avoid collision as well, and
(iv) passive orientation safety, which allows for imperfect sensor coverage of
the robot, i. e., the robot is aware that not everything in its environment
will be visible. We complement these provably correct safety properties with
liveness properties: we prove that provably safe motion is flexible enough to
let the robot still navigate waypoints and pass intersections. We use hybrid
system models and theorem proving techniques that describe and formally verify
the robot's discrete control decisions along with its continuous, physical
motion. Moreover, we formally prove that safety can still be guaranteed despite
sensor uncertainty and actuator perturbation, and when control choices for more
aggressive maneuvers are introduced. Our verification results are generic in
the sense that they are not limited to the particular choices of one specific
control algorithm but identify conditions that make them simultaneously apply
to a broad class of control algorithms.


title: Universal graphs at $\aleph_{\omega_1+1}$

abstract:
  Starting from a supercompact cardinal we build a model in which
$2^{\aleph_{\omega_1}}=2^{\aleph_{\omega_1+1}}=\aleph_{\omega_1+3}$ but there
is a jointly universal family of size $\aleph_{\omega_1+2}$ of graphs on
$\aleph_{\omega_1+1}$. The same technique will work for any uncountable
cardinal in place of $\omega_1$.


title:
A Limited-Feedback Approximation Scheme for Optimal Switching Problems
  with Execution Delays

abstract:
  We consider a type of optimal switching problems with non-uniform execution
delays and ramping. Such problems frequently occur in the operation of
economical and engineering systems. We first provide a solution to the problem
by applying a probabilistic method. The main contribution is, however, a scheme
for approximating the optimal control by limiting the information in the
state-feedback. In a numerical example the approximation routine gives a
considerable computational performance enhancement, when compared to a
conventional algorithm.


title: Virial estimates for hard spheres

abstract:
  We review a virial-type estimate which bounds the strength of interaction for
a gas of $N$ hard spheres (billiard balls) dispersing into Euclidean space
$\mathbb{R}^d$. This type of estimate has been known for decades in the context
of (semi-)dispersing billiards, and is essentially trivial in that context. Our
goal, however, is to write virial estimates in a way which may lend insight
into the problem of rigorously deriving Boltzmann's equation (cf. Lanford's
theorem). Using virial estimates, we provide a short proof of lower bounds
(sharp up to powers of logarithms) on the convergence rate of the first
marginal in Lanford's theorem. Such lower bounds will often, but not always,
follow trivially from energy conservation, the proof we present holds assuming
only that the limiting dynamics is regular enough and does not reduce to free
transport.


title:
Deriving the exact nonadiabatic quantum propagator in the mapping
  variable representation

abstract:
  We derive an exact quantum propagator for nonadiabatic dynamics in
multi-state systems using the mapping variable representation, where
classical-like Cartesian variables are used to represent both continuous
nuclear degrees of freedom and discrete electronic states. The resulting
expression is a Moyal series that, when suitably approximated, can allow for
the use of classical dynamics to efficiently model large systems. We
demonstrate that different truncations of the exact propagator lead to existing
approximate semiclassical and mixed quantum-classical methods and we derive an
associated error term for each method. Furthermore, by combining the
imaginary-time path-integral representation of the Boltzmann operator with the
exact propagator, we obtain an analytic expression for thermal quantum
real-time correlation functions. These results provide a rigorous theoretical
foundation for the development of accurate and efficient classical-like
dynamics to compute observables such as electron transfer reaction rates in
complex quantized systems.


title:
Algorithms for Learning Sparse Additive Models with Interactions in High
  Dimensions

abstract:
  A function $f: \mathbb{R}^d \rightarrow \mathbb{R}$ is a Sparse Additive
Model (SPAM), if it is of the form $f(\mathbf{x}) = \sum_{l \in
\mathcal{S}}\phi_{l}(x_l)$ where $\mathcal{S} \subset [d]$, $|\mathcal{S}| \ll
d$. Assuming $\phi$'s, $\mathcal{S}$ to be unknown, there exists extensive work
for estimating $f$ from its samples. In this work, we consider a generalized
version of SPAMs, that also allows for the presence of a sparse number of
second order interaction terms. For some $\mathcal{S}_1 \subset [d],
\mathcal{S}_2 \subset {[d] \choose 2}$, with $|\mathcal{S}_1| \ll d,
|\mathcal{S}_2| \ll d^2$, the function $f$ is now assumed to be of the form:
$\sum_{p \in \mathcal{S}_1}\phi_{p} (x_p) + \sum_{(l,l^{\prime}) \in
\mathcal{S}_2}\phi_{(l,l^{\prime})} (x_l,x_{l^{\prime}})$. Assuming we have the
freedom to query $f$ anywhere in its domain, we derive efficient algorithms
that provably recover $\mathcal{S}_1,\mathcal{S}_2$ with finite sample bounds.
Our analysis covers the noiseless setting where exact samples of $f$ are
obtained, and also extends to the noisy setting where the queries are corrupted
with noise. For the noisy setting in particular, we consider two noise models
namely: i.i.d Gaussian noise and arbitrary but bounded noise. Our main methods
for identification of $\mathcal{S}_2$ essentially rely on estimation of sparse
Hessian matrices, for which we provide two novel compressed sensing based
schemes. Once $\mathcal{S}_1, \mathcal{S}_2$ are known, we show how the
individual components $\phi_p$, $\phi_{(l,l^{\prime})}$ can be estimated via
additional queries of $f$, with uniform error bounds. Lastly, we provide
simulation results on synthetic data that validate our theoretical findings.


title:
Locally homogeneous triples. Extension theorems for parallel sections
  and parallel bundle isomorphisms

abstract:
  Let $M$ be a differentiable manifold and $K$ a Lie group. A locally
homogeneous triple with structure group $K$ on $M$ is a triple $(g,
P\stackrel{p}{\to} M,A)$, where $p:P\to M$ is a principal $K$-bundle on $M$,
$g$ is Riemannian metric on $M$, and $A$ is connection on $P$ such that the
following locally homogeneity condition is satisfied: for every two points $x$,
$x'\in M$ there exists an isometry $\varphi:U\to U'$ between open neighborhoods
$U\ni x$, $U'\ni x'$ with $\varphi(x)=x'$, and a $\varphi$-covering bundle
isomorphism $\Phi:P_U\to P_{U'}$ such that $\Phi^*(A_{U'})=A_U$. If
$(g,P\stackrel{p}{\to} M,A)$ is a locally homogeneous triple on $M$, one can
endow the total space $P$ with a locally homogeneous Riemannian metric such
that $p$ becomes a Riemannian submersion and $K$ acts by isometries. Therefore
the classification of locally homogeneous triples on a given manifold $M$ is an
important problem: it gives an interesting class of geometric manifolds which
are fibre bundles over $M$.
  In this article we will prove a classification theorem for locally
homogeneous triples. We will use this result in a future article in order to
describe explicitly moduli spaces of locally homogeneous triples on Riemann
surfaces.


title: Dark matter annihilation with s-channel internal Higgsstrahlung

abstract:
  We study the scenario of fermionic dark matter that annihilates to standard
model fermions through an s-channel axial vector mediator. We point out that
the well-known chirality suppression of the annihilation cross section can be
alleviated by s-channel internal Higgsstrahlung. The shapes of the cosmic ray
spectra are identical to that of t-channel internal Higgsstrahlung in the limit
of a heavy mediating particle. Unlike the general case of t-channel
bremsstrahlung, s-channel Higgsstrahlung can be the dominant annihilation
process even for Dirac dark matter. Since the s-channel mediator can be a
standard model singlet, collider searches for the mediator are easily
circumvented.


title: Atmospheric Neutrino Status

abstract:
  This conference proceeding discusses new results arising from atmospheric
neutrino detection in the Super-Kamiokande and IceCube experiments.
Super-Kamiokande has measured atmospheric neutrinos in the energy range of 100
MeV-10 TeV and uses this data set to conclusively measure the east-west effect
to 8.0 (6.0) $\sigma$ for electron (muon) neutrinos. IceCube is ideal for
measuring high energy atmospheric neutrinos and has explored how different
production channels for atmospheric neutrinos contribute to the total overall
observed flux. The measurement is consistent with the conventional spectrum,
produced by the decay of pions and kaon, while the contribution from the prompt
channel (due to charm decay) is consistent with zero.


title: The HOD Dichotomy

abstract:
  This paper provides an accessible introduction to some of the work of Woodin
on suitable extender models. We define the HOD conjecture, prove it is
equivalent to a formulation in terms of weak extender models for
supercompactness, and give some of its consequences.


title:
Gradient Bundle Analysis: A Full Topological Approach to Chemical
  Bonding

abstract:
  The "chemical bond" is a central concept in molecular sciences, but there is
no consensus as to what a bond actually is. Therefore, a variety of bonding
models have been developed, each defining the structure of molecules in a
different manner with the goal of explaining and predicting chemical
properties. This thesis describes the initial development of gradient bundle
analysis (GBA), a chemical bonding model that creates a high resolution picture
of chemical interactions within the charge density framework. GBA is based on
concepts from the quantum theory of atoms in molecules (QTAIM), but uses a more
complete picture of the topology and geometry of the electron charge density to
understand and predict bonding interactions. Gradient bundles are defined as
volumes bounded by zero-flux surfaces (ZFSs) in the gradient of the charge
density with well-defined energies. The structure of gradient bundles provides
an avenue for detecting the locations of valence electrons, which correspond to
reactive regions in a molecule. The number of electrons in bonding regions,
which are defined by the lowering of kinetic energy in gradient bundles, is
found to correlate to bond dissociation energy in diatomic molecules.
Furthermore, site reactivity can be understood and predicted by observing the
motion of ZFSs bounding gradient bundles and calculating condensed gradient
bundle Fukui functions. Using only the ground state charge density, I present
preliminary results for a method that predicts which regions in a molecule are
most likely to undergo nucleophilic and electrophilic attack, effectively
locating the HOMO and LUMO.


title: Lubin-Tate Deformation Spaces and Fields of Norms

abstract:
  We construct a tower of fields from the rings $R_n$ which parametrize pairs
$(X,\lambda)$, where $X$ is a deformation of a fixed one-dimensional formal
group $\mathbb{X}$ of finite height $h$, together with a Drinfeld level-$n$
structure $\lambda$. We choose principal prime ideals $\mathfrak{p}_n \mid (p)$
in each ring $R_n$ in a compatible way and consider the field $K'_n$ obtained
by localizing $R_n$ at $\mathfrak{p}_n$, completing, and passing to the
fraction field. By taking the compositum $K_n = K'_n K_0$ of each field with
the completion $K_0$ of a certain unramified extension of $K'_0$, we obtain a
tower of fields $(K_n)_n$ which we prove to be strictly deeply ramified in the
sense of Anthony Scholl. When $h=2$ we also investigate the question of whether
this is a Kummer tower.


title:
Water loss from Earth-sized planets in the habitable zones of ultracool
  dwarfs: Implications for the planets of TRAPPIST-1

abstract:
  Ultracool dwarfs (UCD; $T_{\rm eff}<\sim3000~$K) cool to settle on the main
sequence after $\sim$1 Gyr. For brown dwarfs, this cooling never stops. Their
habitable zone (HZ) thus sweeps inward at least during the first Gyr of their
lives. Assuming they possess water, planets found in the HZ of UCDs have
experienced a runaway greenhouse phase too hot for liquid water prior to
entering the HZ. It has been proposed that such planets are desiccated by this
hot early phase and enter the HZ as dry worlds. Here we model the water loss
during this pre-HZ hot phase taking into account recent upper limits on the XUV
emission of UCDs and using 1D radiation-hydrodynamic simulations. We address
the whole range of UCDs but also focus on the planets recently found around the
$0.08~M_\odot$ dwarf TRAPPIST-1.
  Despite assumptions maximizing the FUV-photolysis of water and the XUV-driven
escape of hydrogen, we find that planets can retain significant amounts of
water in the HZ of UCDs, with a sweet spot in the $0.04$-$0.06~M_\odot$ range.
We also studied the TRAPPIST-1 system using observed constraints on the
XUV-flux. We find that TRAPPIST-1b and c may have lost as much as 15 Earth
Oceans and planet d -- which might be inside the HZ -- may have lost less than
1 Earth Ocean. Depending on their initial water contents, they could have
enough water to remain habitable. TRAPPIST-1 planets are key targets for
atmospheric characterization and could provide strong constraints on the water
erosion around UCDs.


title: Aspects of pQCD at a 100 TeV future hadron collider

abstract:
  In this publication we consider particle production at a future circular
hadron collider with 100 TeV centre of mass energy within the Standard Model,
and in particular their QCD aspects. Accurate predictions for these processes
pose severe theoretical challenges related to large hierarchies of scales and
possible large multiplicities of final state particles. We investigate scaling
patterns in multijet-production rates allowing to extrapolate predictions to
very high final-state multiplicities. Furthermore, we consider large-area QCD
jets and study the expectation for the mean number of subjets to be
reconstructed from their constituents and confront these with analytical
resummed predictions and with the expectation for boosted hadronic decays of
top-quarks and W-bosons. We also discuss the validity of
Higgs-Effective-Field-Theory in making predictions for Higgs-boson production
in association with jets. Finally, we consider the case of New Physics searches
at such a 100 TeV hadron-collider machine and discuss the expectations for
corresponding Standard-Model background processes.


title:
CAIR: Using Formal Languages to Study Routing, Leaking, and Interception
  in BGP

abstract:
  The Internet routing protocol BGP expresses topological reachability and
policy-based decisions simultaneously in path vectors. A complete view on the
Internet backbone routing is given by the collection of all valid routes, which
is infeasible to obtain due to information hiding of BGP, the lack of
omnipresent collection points, and data complexity. Commonly, graph-based data
models are used to represent the Internet topology from a given set of BGP
routing tables but fall short of explaining policy contexts. As a consequence,
routing anomalies such as route leaks and interception attacks cannot be
explained with graphs.
  In this paper, we use formal languages to represent the global routing system
in a rigorous model. Our CAIR framework translates BGP announcements into a
finite route language that allows for the incremental construction of minimal
route automata. CAIR preserves route diversity, is highly efficient, and
well-suited to monitor BGP path changes in real-time. We formally derive
implementable search patterns for route leaks and interception attacks. In
contrast to the state-of-the-art, we can detect these incidents. In practical
experiments, we analyze public BGP data over the last seven years.


title: A Note on Oracle Separations for BQP

abstract:
  In 2009, using the $\textsf{Fourier Checking}$ problem, Aaronson claimed to
construct the relativized worlds such that $\textsf{BQP} \not\subset
\mathsf{BPP_{path}}$ and $\textsf{BQP} \not\subset \textsf{SZK}$. However,
there are subtle errors in the original proof. In this paper, we point out the
issues, and rescue these two separations by using more sophisticated
constructions.
  Meanwhile, we take the opportunity to study the complexity classes
$\mathsf{BPP_{path}}$ and $\textsf{SZK}$. We give general ways to construct
functions which are hard for $\textsf{SZK}$ and $\mathsf{BPP_{path}}$ (in the
query complexity sense). Using these techniques, we give alternative
construction for the oracle separation $\textsf{BQP} \not\subset \textsf{SZK}$,
using only Simon's problem. We also give new oracle separations for
$\textsf{P}^{\textsf{SZK}}$ from $\mathsf{BPP_{path}}$ and
$\textsf{P}^{\textsf{SZK}}$ from $\textsf{QSK}$. The latter result suggests
that $\textsf{P}^{\textsf{SZK}}$ might be strictly larger than $\textsf{SZK}$.


title:
Game-Theoretic Multi-Agent Control and Network Cost Allocation under
  Communication Constraints

abstract:
  Multi-agent networked linear dynamic systems have attracted attention of
researchers in power systems, intelligent transportation, and industrial
automation. The agents might cooperatively optimize a global performance
objective, resulting in social optimization, or try to satisfy their own
selfish objectives using a noncooperative differential game. However, in these
solutions, large volumes of data must be sent from system states to possibly
distant control inputs, thus resulting in high cost of the underlying
communication network. To enable economically-viable communication, a
game-theoretic framework is proposed under the \textit{communication cost}, or
\textit{sparsity}, constraint, given by the number of communicating
state/control input pairs. As this constraint tightens, the system transitions
from dense to sparse communication, providing the trade-off between dynamic
system performance and information exchange. Moreover, using the proposed
sparsity-constrained distributed social optimization and noncooperative game
algorithms, we develop a method to allocate the costs of the communication
infrastructure fairly and according to the agents' diverse needs for feedback
and cooperation. Numerical results illustrate utilization of the proposed
algorithms to enable and ensure economic fairness of wide-area control among
power companies.


title:
A Necessary and Sufficient Condition for Local Maxima of Polynomial
  Modulus Over Unit Disc

abstract:
  An important quantity associated with a complex polynomial $p(z)$ is $\Vert p
\Vert_\infty$, the maximum of its modulus over the unit disc $D$. We prove,
$z_* \in D$ is a local maximum of $|p(z)|$ if and only if $a_*$ satisfies,
$z_*=p(z_*)|p'(z_*)|/p'(z_*)|p(z_*)|$, i.e. it is proportional to its
corresponding Newton direction. This explicit formula gives rise to novel
iterative algorithms for computing $\Vert p \Vert_\infty$. We describe two such
algorithms, including a Newton-like method and present some visualization of
their performance.


title:
Charged Higgs production in association with a top quark at approximate
  NNLO

abstract:
  I present approximate next-to-next-to-leading-order (aNNLO) total and
differential cross sections for charged Higgs production in association with a
top quark at LHC energies. The aNNLO results for the process $bg \rightarrow
tH^-$ are derived from next-to-next-to-leading-logarithm (NNLL) resummation of
soft-gluon corrections. Scale and parton-distribution uncertainties for the
cross sections are shown. The top-quark transverse-momentum and rapidity
distributions are also calculated.


title:
Real eigenvalues of non-symmetric random matrices: Transitions and
  Universality

abstract:
  In the past 20 years, the study of real eigenvalues of non-symmetric real
random matrices has seen important progress. Notwithstanding, central questions
still remain open, such as the characterization of their asymptotic statistics
and the universality thereof. In this letter we show that for a wide class of
matrices, the number $k_n$ of real eigenvalues of a matrix of size $n$ is
asymptotically Gaussian with mean $\bar k_n=\mathcal{O}(\sqrt{n})$ and variance
$\bar k_n(2-\sqrt{2})$. Moreover, we show that the limit distribution of real
eigenvalues undergoes a transition between bimodal for $k_n=o(\sqrt{n})$ to
unimodal for $k_n=\mathcal{O}(n)$, with a uniform distribution at the
transition. We predict theoretically these behaviours in the Ginibre ensemble
using a log-gas approach, and show numerically that they hold for a wide range
of random matrices with independent entries beyond the universality class of
the circular law.


title: Twisted Gromov and Lefschetz invariants associated with bundles

abstract:
  Given a closed symplectic 4-manifold $(X,\omega)$, we define a twisted
version of the Gromov-Taubes invariants for $(X,\omega)$, where the twisting
coefficients are induced by the choice of a surface bundle over $X$. Given a
fibered 3-manifold $Y$, we similarly construct twisted Lefschetz zeta functions
associated with surface bundles: we prove that these are essentially equivalent
to the Jiang's Lefschetz zeta functions of $Y$, twisted by the representations
of $\pi_1(Y)$ that are induced by monodromy homomorphisms of surface bundles
over $Y$. This leads to an interpretation of the corresponding twisted
Reidemeister torsions of $Y$ in terms of products of "local" commutative
Reidemeister torsions. Finally we relate the two invariants by proving that,
for any fixed closed surface bundle $\mathcal{B}$ over $Y$, the corresponding
twisted Lefschetz zeta function coincides with the Gromov-Taubes invariant of
$S^1 \times Y$ twisted by the bundle over $S^1 \times Y$ naturally induced by
$\mathcal{B}$.


title: The Attenuated Space Poset $\mathcal{A}_q(N, M)$

abstract:
  In this paper, we study the incidence algebra $T$ of the attenuated space
poset $\mathcal{A}_q(N, M)$. We consider the following topics. We consider some
generators of $T$: the raising matrix $R$, the lowering matrix $L$, and a
certain diagonal matrix $K$. We describe some relations among $R, L, K$. We put
these relations in an attractive form using a certain matrix $S$ in $T$. We
characterize the center $Z(T)$. Using $Z(T)$, we relate $T$ to the quantum
group $U_\tau({\mathfrak{sl}}_2)$ with $\tau^2=q$. We consider two elements $A,
A^*$ in $T$ of a certain form. We find necessary and sufficient conditions for
$A, A^*$ to satisfy the tridiagonal relations. Let $W$ denote an irreducible
$T$-module. We find necessary and sufficient conditions for the above $A, A^*$
to act on $W$ as a Leonard pair.


title: Pixelated VLC-backscattering for Self-charging Indoor IoT Devices

abstract:
  Visible light communication (VLC) backscatter has been proposed as a wireless
access option for Internet of Things (IoT). However, the throughput of the
state-of-the-art VLC backscatter is limited by simple single-carrier pulsed
modulation scheme, such as on-off keying (OOK). In this paper, a novel
pixelated VLC backscatter is proposed and implemented to overcome the channel
capacity limitation. In particular, multiple smaller VLC backscatters,
switching on or off, are integrated to generate multi-level signals, which
enables the usage of more advanced modulation schemes than OOK. Based on
experimental results, rate adaptation at different communication distances can
be employed to enhance the achievable data rate. Compared to OOK, the data rate
can be tripled when 8-PAM is used at 2 meters. In general, $n$-fold throughput
enhancement is realized by utilizing $n$ smaller VLC backscatters while
incurring negligible additional energy using the same device space as that of a
single large backscatter.


title: Random Access Design for Wireless Control Systems

abstract:
  Interferences arising between wireless sensor-actuator systems communicating
over shared wireless channels adversely affect closed loop control performance.
To mitigate this problem we design appropriate channel access policies for
wireless control systems subject to channel fading. The design is posed as an
optimization problem where the total transmit power of the sensors is minimized
while desired control performance is guaranteed for each involved control loop.
Control performance is abstracted as a desired expected decrease rate of a
given Lyapunov function for each loop. We prove that the optimal channel access
policies are decoupled and, intuitively, each sensor balances the gains from
transmitting to its actuator with the negative interference effect on all other
control loops. Moreover the optimal policies are of a threshold nature, that
is, a sensor transmits only under favorable local fading conditions. Finally,
we show that the optimal policies can be computed by a distributed iterative
procedure which does not require coordination between the sensors.


title:
Energy conservation for the weak solutions of the compressible
  Navier-Stokes equations

abstract:
  In this paper, we prove the energy conservation for the weak solutions of the
compressible Navier-Stokes equations for any time $t>0$, under certain
conditions. The results hold for the renormalized solutions of the equations
with constant viscosities, as well as the weak solutions of the equations with
degenerate viscosity. Our conditions do not depend on the dimensions. The
energy may conserve on the vacuum for the compressible Navier-Stokes equations
with constant viscosities. Our results are the first ones on the energy
conservation for the weak solutions of the compressible Navier-Stokes
equations.


title:
Full angular spectrum analysis of tensor current contribution to
  $A_{cp}(\tau \rightarrow K_{s} \pi \nu_{\tau})$

abstract:
  Babar collaboration has reported an intriguing opposite sign in the
integrated decay rate asymmetry $A_{cp}(\tau \rightarrow K_{s} \pi \nu_{\tau})$
than that of SM prediction from the known $K^{0}$ - $\bar{K^{0}}$ mixing.
Babar's result deviate from the SM prediction by about 2.7$\sigma$. If the
result stands with higher precision in the future experiments, the observed
sign anomaly in the $A_{cp}(\tau \rightarrow K_{s} \pi \nu_{\tau})$ can most
likely come only from a NP. In this work we present a full angular spectrum
analysis on the contribution to $A_{cp}(\tau \rightarrow K_{s} \pi \nu_{\tau})$
coming from the tensorial term. Assuming the real part of the NP tensorial
coupling is negligible compare to its imaginary part and with $A_{cp}(\tau
\rightarrow K_{s} \pi \nu_{\tau})$ and $Br(\tau \rightarrow K_{s} \pi
\nu_{\tau})$ as data points to fit the imaginary part of the NP coupling, we
have been able to fit the result within 1$\sigma$ of the experimental values.


title:
First hard X-ray observations of the blazar S5 0716+714 with NuSTAR
  during a multiwavelength campaign

abstract:
  We report the results of a multifrequency campaign targeting S5 0716+714 in
the flaring state of the source observed in 2015 January and February. The
observations have been performed using the following instruments: Fermi/Large
Area Telescope (LAT), Nuclear Spectroscopic Telescope Array, X-ray Telescope
and Ultraciolet/Optical Telescope. The elevated flux level was visible in all
frequencies and the outburst consists of five sub-flares. In this paper we
focus on the analysis of the X-ray observations both in the soft and hard
regimes for data collected with NuStar and Swift/XRT. This is the first time,
when hard X-ray observations of the source collected with NuStar are reported.
The studies reveal both low- and high-energy components clearly visible in the
energy band, with the break energy of 8 keV, which is the highest break energy
ever reported for S5 0716+714. The second part of this work is concentrated on
multifrequency observations collected during the flaring activity period. The
variability patterns recorded during the period are characterized using a
fractional variability amplitude and description of the flare profiles. The
correlation studies reveal strong and significant relation between the optical,
ultraviolet and gamma-ray observations, and no time lag is found for any of the
studied relations.


title: Search for neutrinoless double beta decay

abstract:
  We review current experimental efforts to search for neutrinoless double beta
decay (0$\nu\beta\beta$). A description of the selected leading experiments is
given and the strongest recent results are compared in terms of achieved
background indexes and limits on effective Majorana mass. A combined limit is
also shown. The second part of the review covers next generation experiments,
highlighting the challenges and new technologies that may be necessary to
achieve a justifiable discovery potential. A potential synergy with direct dark
matter searches, which could be an especially prudent strategy in case the
axial vector coupling constant is quenched in 0$\nu\beta\beta$ decay, is
emphasized.


title: The Aw-Rascle-Zhang model with constraints

abstract:
  The thesis deals with the Aw-Rascle-Zhang model for traffic. We have applied
the model to describe the influence of a large and slow vehicle (a bus or a
truck) on the traffic. The trajectory of the bus is given by an ODE. The model
can also be applied to the case of a fixed constraint, like a traffic light or
a toll gate. We define two different Riemann solvers: the first one conserves
both the number of cars and the generalized momentum, while the second
conserves only the number of cars. We characterize the invariant domains for
these Riemann solvers. We study two numerical methods based on the Godunov
method to capture the proposed solutions and we track the bus trajectory with a
front-tracking technique. The first method is based on conservation and
captures exactly the solution corresponding to the first Riemann solver. The
second method is based on a non-uniform mesh. Both methods fail to capture the
solutions corresponding to the second Riemann solver for general initial data.
Finally, we prove the existence of solutions for the Cauchy problem for the
second Riemann solver in the case of a fixed constraint, applying the
wave-front tracking method.


title: Depletion of intense fields

abstract:
  The interaction of charged particles and photons with intense electromagnetic
fields gives rise to multi-photon Compton and Breit-Wheeler processes. These
are usually described in the framework of the external field approximation,
where the electromagnetic field is assumed to have infinite energy. However,
the multi-photon nature of these processes implies the absorption of a
significant number of photons, which scales as the external field amplitude
cubed. As a result, the interaction of a highly charged electron bunch with an
intense laser pulse can lead to significant depletion of the laser pulse
energy, thus rendering the external field approximation invalid. We provide
relevant estimates for this depletion and find it to become important in the
interaction between fields of amplitude $a_0 \sim 10^3$ and electron bunches
with charges of the order of 10 nC.


title: Why have asset price properties changed so little in 200 years

abstract:
  We first review empirical evidence that asset prices have had episodes of
large fluctuations and been inefficient for at least 200 years. We briefly
review recent theoretical results as well as the neurological basis of trend
following and finally argue that these asset price properties can be attributed
to two fundamental mechanisms that have not changed for many centuries: an
innate preference for trend following and the collective tendency to exploit as
much as possible detectable price arbitrage, which leads to destabilizing
feedback loops.


title:
The Capacity of Robust Private Information Retrieval with Colluding
  Databases

abstract:
  Private information retrieval (PIR) is the problem of retrieving as
efficiently as possible, one out of $K$ messages from $N$ non-communicating
replicated databases (each holds all $K$ messages) while keeping the identity
of the desired message index a secret from each individual database. The
information theoretic capacity of PIR (equivalently, the reciprocal of minimum
download cost) is the maximum number of bits of desired information that can be
privately retrieved per bit of downloaded information. $T$-private PIR is a
generalization of PIR to include the requirement that even if any $T$ of the
$N$ databases collude, the identity of the retrieved message remains completely
unknown to them. Robust PIR is another generalization that refers to the
scenario where we have $M \geq N$ databases, out of which any $M - N$ may fail
to respond. For $K$ messages and $M\geq N$ databases out of which at least some
$N$ must respond, we show that the capacity of $T$-private and Robust PIR is
$\left(1+T/N+T^2/N^2+\cdots+T^{K-1}/N^{K-1}\right)^{-1}$. The result includes
as special cases the capacity of PIR without robustness ($M=N$) or $T$-privacy
constraints ($T=1$).


title: Superconformal Symmetry in the Kaluza-Klein Spectrum of Warped AdS(3)

abstract:
  We study the Kaluza-Klein spectrum of warped $AdS_3$ compactifications of
type IIB with five-form flux which are dual to $\mathcal{N}=(0,2)$ SCFTs in two
dimensions. We prove that the spectra of fluctuations of both the spin 2 sector
of the graviton and the axio-dilaton are bounded. At the bound the modes have
the correct quantum numbers to be chiral primaries and descendants thereof
respectively. Moreover, we prove that the same modes give rise to superpartners
in the dilatino spectrum. Our results show that a subset of the mesonic chiral
ring of the dual SCFT is isomorphic to the first Kohn-Rossi cohomology groups.
As an example, we consider the compactification of four-dimensional $Y^{p,q}$
theories on Riemann surfaces for the case of the universal twist. We conclude
by studying fluctuations of the three-form, where we are able to identify Betti
multiplets after imposing some mild assumptions.


title: Secondary Electron Emission from Surfaces with Small Structure

abstract:
  It is found that for objects possessing small surface structures with
differing radii of curvature the secondary electron emission (SEE) yield may be
significantly higher than for objects with smooth surfaces of the same
material. The effect is highly pronounced for surface structures of nanometer
scale, often providing a more than 100% increase of the SEE yield. The results
also show that the SEE yield from surfaces with structure does not show an
universal dependence on the energy of the primary, incident electrons as it is
found for flat surfaces in experiments. We derive conditions for the
applicability of the conventional formulation of SEE using the simplifying
assumption of universal dependence. Our analysis provides a basis for studying
low-energy electron emission from nano structured surfaces under a penetrating
electron beam important in many technological applications.


title:
Navigation Functions for Convex Potentials in a Space with Convex
  Obstacles

abstract:
  Given a convex potential in a space with convex obstacles, an artificial
potential is used to navigate to the minimum of the natural potential while
avoiding collisions. The artificial potential combines the natural potential
with potentials that repel the agent from the border of the obstacles. This is
a popular approach to navigation problems because it can be implemented with
spatially local information that is acquired during operation time. Artificial
potentials can, however, have local minima that prevent navigation to the
minimum of the natural potential. This paper derives conditions that guarantee
artificial potentials have a single minimum that is arbitrarily close to the
minimum of the natural potential. The qualitative implication is that
artificial potentials succeed when either the condition number-- the ratio of
the maximum over the minimum eigenvalue-- of the Hessian of the natural
potential is not large and the obstacles are not too flat or when the
destination is not close to the border of an obstacle. Numerical analyses
explore the practical value of these theoretical conclusions.


title:
Absolute Stability and Spatiotemporal Long-Range Order in Floquet
  systems

abstract:
  Recent work has shown that a variety of novel phases of matter arise in
periodically driven Floquet systems. Among these are many-body localized phases
which spontaneously break global symmetries and exhibit novel multiplets of
Floquet eigenstates separated by quantized quasienergies. Here we show that
these properties are stable to all weak local deformations of the underlying
Floquet drives -- including those that explicitly break the defining symmetries
-- and that the models considered until now occupy sub-manifolds within these
larger "absolutely stable" phases. While these absolutely stable phases have no
explicit global symmetries, they spontaneously break Hamiltonian dependent
emergent symmetries, and thus continue to exhibit the novel multiplet
structure. The multiplet structure in turn encodes characteristic oscillations
of the emergent order parameter at multiples of the fundamental period.
Altogether these phases exhibit a form of simultaneous long-range order in
space and time which is new to quantum systems. We describe how this
spatiotemporal order can be detected in experiments involving quenches from a
broad class of initial states.


title:
Spectral shearing of quantum light pulses by electro-optic phase
  modulation

abstract:
  Frequency conversion of non-classical light enables robust encoding of
quantum information based upon spectral multiplexing that is particularly
well-suited to integrated-optics platforms. Here we present an intrinsically
deterministic linear-optics approach to spectral shearing of quantum light
pulses and show it preserves the wave-packet coherence and quantum nature of
light. The technique is based upon an electro-optic Doppler shift to implement
frequency shear of heralded single-photon wave packets by $\pm 200$ GHz, which
can be scaled to an arbitrary shift. These results demonstrate a
reconfigurable, unitary method to controlling the spectral-temporal mode
structure of quantum light.


title: The isometry degree of a computable copy of $\ell^p$

abstract:
  When $p$ is a computable real so that $p \geq 1$, the isometry degree of a
computable copy $\mathcal{B}$ of $\ell^p$ is defined to be the least powerful
Turing degree that computes a linear isometry of $\ell^p$ onto $\mathcal{B}$.
We show that this degree always exists and that when $p \neq 2$ these degrees
are precisely the c.e. degrees.


title:
A new scheme for short baseline electron antineutrino disappearance
  study

abstract:
  A new scheme for the short baseline electron antineutrino (${\bar{\nu}}_{e}$)
disappearance study is investigated. We propose to use an intense neutron
emitter, $^{252}$Cf, which produces $^{8}$Li isotope through the
$^{7}$Li(n,$\gamma$)$^{8}$Li reaction; $^{8}$Li is a ${\bar{\nu}}_{e}$ emitter
via $\beta^{-}$ decay. Because this ${\bar{\nu}}_{e}$ source needs neither
accelerator nor reactor facilities, the ${\bar{\nu}}_{e}$ can be placed on any
neutrino detectors as closely as possible. This short baseline circumstance
with a suitable detector enables us to study the existence of possible sterile
neutrinos, in particular, on 1 eV mass scale. Also, complementary comparison
studies among different neutrino detectors can become feasible by using
${\bar{\nu}}_{e}$ from the $^{8}$Li source. As an example, applications to
hemisphere and cylinder shape scintillator detectors are performed in detail
with the expectation signal modification by the sterile neutrino. Sensitivities
to mass and mixing angles of sterile neutrinos are also presented for
comparison with those of other neutrino experiments.


title:
Galactic winds driven by isotropic and anisotropic cosmic ray diffusion
  in disk galaxies

abstract:
  The physics of cosmic rays (CR) is a promising candidate for explaining the
driving of galactic winds and outflows. Recent galaxy formation simulations
have demonstrated the need for active CR transport either in the form of
diffusion or streaming to successfully launch winds in galaxies. However, due
to computational limitations, most previous simulations have modeled CR
transport isotropically. Here, we discuss high resolution simulations of
isolated disk galaxies in a $10^{11}\rm{M_\odot}$ halo with the moving mesh
code {\sc Arepo} that include injection of CRs from supernovae, advective
transport, CR cooling, and CR transport through isotropic or anisotropic
diffusion. We show that either mode of diffusion leads to the formation of
strong bipolar outflows. However, they develop significantly later in the
simulation with anisotropic diffusion compared to the simulation with isotropic
diffusion. Moreover, we find that isotropic diffusion allows most of the CRs to
quickly diffuse out of the disk, while in the simulation with anisotropic
diffusion, most CRs remain in the disk once the magnetic field becomes
dominated by its azimuthal component, which occurs after $\sim 300\,{\rm
Myrs}$. This has important consequences for the gas dynamics in the disk. In
particular, we show that isotropic diffusion strongly suppresses the
amplification of the magnetic field in the disk compared to anisotropic or no
diffusion models. We therefore conclude that reliable simulations which include
CR transport inevitably need to account for anisotropic diffusion.


title:
ALMA Investigation of Vibrationally Excited HCN/HCO+/HNC Emission Lines
  in the AGN-Hosting Ultraluminous Infrared Galaxy IRAS 20551-4250

abstract:
  We present the results of ALMA Cycle 2 observations of the ultraluminous
infrared galaxy, IRAS 20551-4250, at HCN/HCO+/HNC J=3-2 lines at both
vibrational-ground (v=0) and vibrationally excited (v2=1) levels. This galaxy
contains a luminous buried active galactic nucleus (AGN), in addition to
starburst activity, and our ALMA Cycle 0 data revealed a tentatively detected
vibrationally excited HCN v2=1f J=4-3 emission line. In our ALMA Cycle 2 data,
the HCN/HCO+/HNC J=3-2 emission lines at v=0 are clearly detected. The HCN and
HNC v2=1f J=3-2 emission lines are also detected, but the HCO+ v2=1f J=3-2
emission line is not. Given the high-energy level of v2=1 and the resulting
difficulty of collisional excitation, we compared these results with those of
the calculation of infrared radiative pumping, using the available infrared
5-35 micron spectrum. We found that all of the observational results were
reproduced, if the HCN abundance was significantly higher than that of HCO+ and
HNC. The flux ratio and excitation temperature between v2=1f and v=0, after
correction for possible line opacity, suggests that infrared radiative pumping
affects rotational (J-level) excitation at v=0 at least for HCN and HNC. The
HCN-to-HCO+ v=0 flux ratio is higher than those of starburst-dominated regions,
and will increase even more when thederived high HCN opacity is corrected. The
enhanced HCN-to-HCO+ flux ratio in this AGN-hosting galaxy can be explained by
the high HCN-to-HCO+ abundance ratio and sufficient HCN excitation at up to
J=4, rather than the significantly higher efficiency of infrared radiative
pumping for HCN than HCO+.


title:
The Unexpected, Long-Lasting, UV Rebrightening of the Super-Luminous
  Supernova ASASSN-15lh

abstract:
  Given its peak luminosity and early-time spectra, ASASSN-15lh was classified
as the most luminous supernova (SN) ever discovered (Dong et al. 2016). Here we
report a UV rebrightening of ASASSN-15lh observed with Swift during our
follow-up campaign. The rebrightening began at $t \simeq$ 90 days (observer
frame) after the primary peak and was followed by a $\sim 120$-day long plateau
in the bolometric luminosity, before starting to fade again at $t\simeq 210$
days. ASASSN-15lh rebrightened in the Swift UV bands by $\Delta m_{UVW2} \simeq
-1.75$ mag, $\Delta m_{UVM2} \simeq -1.25$ mag, and $\Delta m_{UVW1} \simeq
-0.8$ mag, but did not rebrighten in the optical bands. Throughout its initial
decline, subsequent rebrightening, and renewed decline, the spectra did not
show evidence of interactions between the ejecta and circumstellar medium (CSM)
such as narrow emission lines. There are hints of weak H$\alpha$ emission at
late-times, but Margutti et al. (2016) have shown that it is narrow line
emission consistent with star formation in the host nucleus. By fitting a
blackbody we find that during the rebrightening the effective photospheric
temperature increased from $T_{BB} \simeq 11000$ K to $T_{BB} \simeq 18000$ K.
Over the $\sim$ 550 days since its detection, ASASSN-15lh has radiated $\sim
1.7 - 1.9 \times 10^{52}$ ergs. Although its physical nature remains uncertain,
the evolution of ASASSN-15lh's photospheric radius, its radiated energy, and
the implied event rate, are all more similar to those of H-poor superluminous
supernovae (SLSNe-I) than to tidal disruption events (TDEs).


title:
Mass Transport and Turbulence in Gravitationally Unstable Disk Galaxies
  II: The Effects of Star Formation Feedback

abstract:
  Self-gravity and stellar feedback are capable of driving turbulence and
transporting mass and angular momentum in disk galaxies, but the balance
between them is not well understood. In the previous paper in this series, we
showed that gravity alone can drive turbulence in galactic disks, regulate
their Toomre $Q$ parameters to $\sim$ 1, and transport mass inwards at a rate
sufficient to fuel star formation in the centers of present-day galaxies. In
this paper we extend our models to include the effects of star formation
feedback. We show that feedback suppresses galaxies' star formation rates by a
factor of $\sim$ 5 and leads to the formation of a multi-phase atomic and
molecular ISM. Both the star formation rate and the phase balance produced in
our simulations agree well with observations of nearby spirals. After our
galaxies reach steady state, we find that the inclusion of feedback actually
lowers the gas velocity dispersion slightly compared to the case of pure
self-gravity, and also slightly reduces the rate of inward mass transport.
Nevertheless, we find that, even with feedback included, our galactic disks
self-regulate to $Q$ $\sim$ 1, and transport mass inwards at a rate sufficient
to supply a substantial fraction of the inner disk star formation. We argue
that gravitational instability is therefore likely to be the dominant source of
turbulence and transport in galactic disks, and that it is responsible for
fueling star formation in the inner parts of galactic disks over cosmological
times.


title:
Building disc structure and galaxy properties through angular momentum:
  The DARK SAGE semi-analytic model

abstract:
  We present the new semi-analytic model of galaxy evolution, DARK SAGE, a
heavily modified version of the publicly available SAGE code. The model is
designed for detailed evolution of galactic discs. We evolve discs in a series
of annuli with fixed specific angular momentum, which allows us to make
predictions for the radial and angular-momentum structure of galaxies. Most
physical processes, including all channels of star formation and associated
feedback, are performed in these annuli. We present the surface density
profiles of our model spiral galaxies, both as a function of radius and
specific angular momentum, and find the discs naturally build a
pseduobulge-like component. Our main results are focussed on predictions
relating to the integrated mass--specific angular momentum relation of stellar
discs. The model produces a distinct sequence between these properties in
remarkable agreement with recent observational literature. We investigate the
impact Toomre disc instabilities have on shaping this sequence and find they
are crucial for regulating both the mass and spin of discs. Without
instabilities, high-mass discs would be systematically deficient in specific
angular momentum by a factor of ~2.5, with increased scatter. Instabilities
also appear to drive the direction in which the mass--spin sequence of spiral
galaxy discs evolves. With them, we find galaxies of fixed mass have higher
specific angular momentum at later epochs.