title:
Checks and Balances: A Low-complexity High-gain Uplink Power Controller
  for CoMP

abstract:
  Coordinated Multipoint (CoMP) promised substantial throughput gain for
next-generation cellular systems. However, realizing this gain is costly in
terms of pilots and backhaul bandwidth, and may require substantial
modifications in physicallayer hardware. Targeting efficient throughput gain,
we develop a novel coordinated power control scheme for uplink cellular
networks called Checks and Balances (C&B), which checks the received signal
strength of one user and its generated interference to neighboring base
stations, and balances the two. C&B has some highly attractive advantages: C&B
(i) can be implemented easily in software, (ii) does not require to upgrade
non-CoMP physicallayer hardware, (iii) allows for fully distributed
implementation for each user equipment (UE), and (iv) does not need extra
pilots or backhaul communications. We evaluate the throughput performance of
C&B on an uplink LTE system-level simulation platform, which is carefully
calibrated with Huawei. Our simulation results show that C&B achieves much
better throughput performance, compared to several widely-used power control
schemes.


title: Propagation of Chaos and Poisson Hypothesis

abstract:
  We establish the Strong Poisson Hypothesis for symmetric closed networks. In
particular, the asymptotic independence of the nodes -- as the size of the
system tends to infinity -- is proved.


title:
Continuous 40 GW/cm$^2$ laser intensity in a near-concentric optical
  cavity

abstract:
  Manipulating free-space electron wave functions with laser fields can bring
about new electron-optical elements for transmission electron microscopy. In
particular, a Zernike phase plate would enable high-contrast imaging of soft
matter, leading to new opportunities in structural biology and materials
science. A Zernike plate can be implemented using a tight, intense CW laser
focus that shifts the phase of the electron wave by the ponderomotive
potential. Here, we use a near-concentric cavity to focus 7.5 kW of circulating
laser power at 1064 nm into a 7 $\mu$m waist, setting a record for CW laser
intensity and establishing a pathway to ponderomotive phase contrast TEM.


title: Havens: Explicit Reliable Memory Regions for HPC Applications

abstract:
  Supporting error resilience in future exascale-class supercomputing systems
is a critical challenge. Due to transistor scaling trends and increasing memory
density, scientific simulations are expected to experience more interruptions
caused by transient errors in the system memory. Existing hardware-based
detection and recovery techniques will be inadequate to manage the presence of
high memory fault rates.
  In this paper we propose a partial memory protection scheme based on
region-based memory management. We define the concept of regions called havens
that provide fault protection for program objects. We provide reliability for
the regions through a software-based parity protection mechanism. Our approach
enables critical program objects to be placed in these havens. The fault
coverage provided by our approach is application agnostic, unlike
algorithm-based fault tolerance techniques.


title: Adaptive matching pursuit for sparse signal recovery

abstract:
  Spike and Slab priors have been of much recent interest in signal processing
as a means of inducing sparsity in Bayesian inference. Applications domains
that benefit from the use of these priors include sparse recovery, regression
and classification. It is well-known that solving for the sparse coefficient
vector to maximize these priors results in a hard non-convex and mixed integer
programming problem. Most existing solutions to this optimization problem
either involve simplifying assumptions/relaxations or are computationally
expensive. We propose a new greedy and adaptive matching pursuit (AMP)
algorithm to directly solve this hard problem. Essentially, in each step of the
algorithm, the set of active elements would be updated by either adding or
removing one index, whichever results in better improvement. In addition, the
intermediate steps of the algorithm are calculated via an inexpensive Cholesky
decomposition which makes the algorithm much faster. Results on simulated data
sets as well as real-world image recovery challenges confirm the benefits of
the proposed AMP, particularly in providing a superior cost-quality trade-off
over existing alternatives.


title: Extremes of the internal energy of the Potts model on cubic graphs

abstract:
  We prove tight upper and lower bounds on the internal energy per particle
(expected number of monochromatic edges per vertex) in the anti-ferromagnetic
Potts model on cubic graphs at every temperature and for all $q \ge 2$. This
immediately implies corresponding tight bounds on the anti-ferromagnetic Potts
partition function.
  Taking the zero-temperature limit gives new results in extremal
combinatorics: the number of $q$-colorings of a $3$-regular graph, for any $q
\ge 2$, is maximized by a union of $K_{3,3}$'s. This proves the $d=3$ case of a
conjecture of Galvin and Tetali.


title: Study on the Abundance Discrepancy Problem in the Magellanic Clouds

abstract:
  We present chemical abundances of carbon (C) and oxygen (O) in the Large and
Small Magellanic Clouds from deep and high-quality optical spectra of HII
regions. The data have been taken using the Ultraviolet-Visual Echelle
Spectrograph at the 8.2-m Very Large Telescope with the goal of detecting the
faint CII and OII recombination lines. For all the objects of the sample, we
determine C^2+ abundances from recombination lines and O^2+ abundances from
recombination lines and collisionally excited lines. In addition, we calculate
the abundance discrepancy factors (ADFs) for O^2+ and C^2+, as well as the O/H,
C/H and C/O ratios. We study the behaviour of the ADF comparing the values
obtained in the Magellanic Clouds with those obtained for other HII regions in
different galaxies. We also compare the nebular and stellar abundances in two
regions of the sample. Finally, we discuss the chemical evolution of the MCs
through the O/H, C/H and C/O radial gradients and the changes of the C/O ratio
as a function of O/H.


title:
Probing ultrafast \pi\pi*/n\pi* internal conversion in organic
  chromophores via K-edge resonant absorption

abstract:
  Organic chromophores with heteroatoms possess an important excited state
relaxation channel from an optically allowed {\pi}{\pi}* to a dark
n{\pi}*state. We exploit the element and site specificity of soft x-ray
absorption spectroscopy to selectively follow the electronic change during the
{\pi}{\pi}*/n{\pi}* internal conversion. As a hole forms in the n orbital
during {\pi}{\pi}*/n{\pi}* internal conversion, the near edge x-ray absorption
fine structure (NEXAFS) spectrum at the heteroatom K-edge exhibits an
additional resonance. We demonstrate the concept with the nucleobase thymine, a
prototypical heteroatomic chromophore. With the help of time resolved NEXAFS
spectroscopy at the oxygen K-edge, we unambiguously show that
{\pi}{\pi}*/n{\pi}* internal conversion takes place within (60 \pm 30) fs.
High-level coupled cluster calculations on the isolated molecules used in the
experiment confirm the superb electronic structure sensitivity of this new
method for excited state investigations.


title:
A Joint Sparse Recovery Framework for Accurate Reconstruction of
  Inclusions in Elastic Media

abstract:
  A robust algorithm is proposed to reconstruct the spatial support and the
Lam\'e parameters of multiple inclusions in a homogeneous background elastic
material using a few measurements of the displacement field over a finite
collection of boundary points. The algorithm does not require any linearization
or iterative update of Green's function but still allows very accurate
reconstruction. The breakthrough comes from a novel interpretation of
Lippmann-Schwinger type integral representation of the displacement field in
terms of unknown densities having common sparse support on the location of
inclusions. Accordingly, the proposed algorithm consists of a two-step
approach. First, the localization problem is recast as a joint sparse recovery
problem that renders the densities and the inclusion support simultaneously.
Then, a noise robust constrained optimization problem is formulated for the
reconstruction of elastic parameters. An efficient algorithm is designed for
numerical implementation using the Multiple Sparse Bayesian Learning (M-SBL)
for joint sparse recovery problem and the Constrained Split Augmented
Lagrangian Shrinkage Algorithm (C-SALSA) for the constrained optimization
problem. The efficacy of the proposed framework is manifested through extensive
numerical simulations. To the best of our knowledge, this is the first
algorithm tailored for parameter reconstruction problems in elastic media using
highly under-sampled data in the sense of Nyquist rate.


title:
Synthesis of Shared Control Protocols with Provable Safety and
  Performance Guarantees

abstract:
  We formalize synthesis of shared control protocols with correctness
guarantees for temporal logic specifications. More specifically, we introduce a
modeling formalism in which both a human and an autonomy protocol can issue
commands to a robot towards performing a certain task. These commands are
blended into a joint input to the robot. The autonomy protocol is synthesized
using an abstraction of possible human commands accounting for randomness in
decisions caused by factors such as fatigue or incomprehensibility of the
problem at hand. The synthesis is designed to ensure that the resulting robot
behavior satisfies given safety and performance specifications, e.g., in
temporal logic. Our solution is based on nonlinear programming and we address
the inherent scalability issue by presenting alternative methods. We assess the
feasibility and the scalability of the approach by an experimental evaluation.


title: Accurate initial conditions in mixed Dark Matter--Baryon simulations

abstract:
  We quantify the error in the results of mixed baryon--dark-matter
hydrodynamic simulations, stemming from outdated approximations for the
generation of initial conditions. The error at redshift 0 in contemporary large
simulations, is of the order of few to ten percent in the power spectra of
baryons and dark matter, and their combined total-matter power spectrum. After
describing how to properly assign initial displacements and peculiar velocities
to multiple species, we review several approximations: (1) {using the
total-matter power spectrum to compute displacements and peculiar velocities of
both fluids}, (2) scaling the linear redshift-zero power spectrum back to the
initial power spectrum using the Newtonian growth factor ignoring homogeneous
radiation, (3) using longitudinal-gauge velocities with synchronous-gauge
densities, and (4) ignoring the phase-difference in the Fourier modes for the
offset baryon grid, relative to the dark-matter grid. Three of these
approximations do not take into account that dark matter and baryons experience
a scale-dependent growth after photon decoupling, which results in directions
of velocity which are not the same as their direction of displacement. We
compare the outcome of hydrodynamic simulations with these four approximations
to our reference simulation, all setup with the same random seed and simulated
using Gadget-III.


title:
The Spiral Wave Instability Induced by a Giant Planet: I. Particle
  Stirring in the Inner Regions of Protoplanetary Disks

abstract:
  We have recently shown that spiral density waves propagating in accretion
disks can undergo a parametric instability by resonantly coupling with and
transferring energy into pairs of inertial waves (or inertial-gravity waves
when buoyancy is important). In this paper, we perform inviscid
three-dimensional global hydrodynamic simulations to examine the growth and
consequence of this instability operating on the spiral waves driven by a
Jupiter-mass planet in a protoplanetary disk. We find that the spiral waves are
destabilized via the spiral wave instability (SWI), generating hydrodynamic
turbulence and sustained radially-alternating vertical flows that appear to be
associated with long wavelength inertial modes. In the interval $0.3~R_p \leq R
\leq 0.7~R_p$, where $R_p$ denotes the semi-major axis of the planetary orbit
(assumed to be 5~au), the estimated vertical diffusion rate associated with the
turbulence is characterized by $\alpha_{\rm diff} \sim (0.2-1.2) \times
10^{-2}$. For the disk model considered here, the diffusion rate is such that
particles with sizes up to several centimeters are vertically mixed within the
first pressure scale height. This suggests that the instability of spiral waves
launched by a giant planet can significantly disperse solid particles and trace
chemical species from the midplane. In planet formation models where the
continuous local production of chondrules/pebbles occurs over Myr time scales
to provide a feedstock for pebble accretion onto these bodies, this stirring of
solid particles may add a time constraint: planetary embryos and large
asteroids have to form before a gas giant forms in the outer disk, otherwise
the SWI will significantly decrease the chondrule/pebble accretion efficiency.


title: Characterizing Intra-cluster light in the Hubble Frontier Fields

abstract:
  We investigate the intra-cluster light (ICL) in the 6 Hubble Frontier Field
clusters at $0.3<z<0.6$. We employ a new method, which is free from any
functional form of the ICL profile, and exploit the unprecedented depth of this
Hubble Space Telescope imaging to map the ICL's diffuse light out to
clustrocentric radii $R\sim300$kpc ($\mu_{\rm ICL}\sim27$mag arcsec$^{-2}$).
From these maps, we construct radial color and stellar mass profiles via SED
fitting and find clear negative color gradients in all systems with increasing
distance from the Brightest Cluster Galaxy (BCG). While this implies older/more
metal rich stellar components in the inner part of the ICL, we find the ICL
mostly consists of a $<2$Gyr population, and plausibly originated with $\log
M_*/M_\odot<10$ cluster galaxies. Further, we find 10-15% of the ICL's mass at
large radii ($>150$kpc) lies in a younger/bluer stellar population
($\sim1$Gyr), a phenomenon not seen in local samples. We attribute this light
to the higher fraction of starforming/(post-)starburst galaxies in clusters at
$z\sim0.5$. Ultimately, we find the ICL's total mass to be $\log M_{\rm *}^{\rm
ICL}/M_\odot\sim11$-12, constituting 5%-20% of the clusters' total stellar
mass, or about a half of the value at $z\sim0$. The above implies distinct
formation histories for the ICL and BCGs/other massive cluster galaxies; i.e.
the ICL at this epoch is still being constructed rapidly
($\sim40M_\odot$yr$^{-1}$), while the BCGs have mostly completed their
evolution. To be consistent with the ICL measurements of local massive
clusters, such as the Virgo, our data suggest mass acquisition mainly from
quiescent cluster galaxies is the principal source of ICL material in the
subsequent $\sim$5 Gyr of cosmic time.


title:
H0LiCOW VI. Testing the fidelity of lensed quasar host galaxy
  reconstruction

abstract:
  The empirical correlation between the mass of a super-massive black hole
(MBH) and its host galaxy properties is widely considered to be evidence of
their co-evolution. A powerful way to test the co-evolution scenario and learn
about the feedback processes linking galaxies and nuclear activity is to
measure these correlations as a function of redshift. Unfortunately, currently
MBH can only be estimated in active galaxies at cosmological distances. At
these distances, bright active galactic nuclei (AGN) can outshine the host
galaxy, making it extremely difficult to measure the host's luminosity.
Strongly lensed AGNs provide in principle a great opportunity to improve the
sensitivity and accuracy of the host galaxy luminosity measurements as the host
galaxy is magnified and more easily separated from the point source, provided
the lens model is sufficiently accurate. In order to measure the MBH-L
correlation with strong lensing, it is necessary to ensure that the lens
modelling is accurate, and that the host galaxy luminosity can be recovered to
at least a precision and accuracy better than that of the typical MBH
measurement. We carry out extensive and realistic simulations of deep Hubble
Space Telescope observations of lensed AGNs obtained by our collaboration. We
show that the host galaxy luminosity can be recovered with better accuracy and
precision than the typical uncertainty on MBH(~ 0.5 dex) for hosts as faint as
2-4 magnitudes dimmer than the AGN itself. Our simulations will be used to
estimate bias and uncertainties on the actual measurements to be presented in a
future paper.


title:
Chemistry and Kinematics of the Late-Forming Dwarf Irregular Galaxies
  Leo A, Aquarius, and Sagittarius DIG

abstract:
  We present Keck/DEIMOS spectroscopy of individual stars in the relatively
isolated Local Group dwarf galaxies Leo A, Aquarius, and the Sagittarius dwarf
irregular galaxy. The three galaxies--but especially Leo A and Aquarius--share
in common delayed star formation histories relative to many other isolated
dwarf galaxies. The stars in all three galaxies are supported by dispersion. We
found no evidence of stellar velocity structure, even for Aquarius, which has
rotating HI gas. The velocity dispersions indicate that all three galaxies are
dark matter-dominated, with dark-to-baryonic mass ratios ranging from
$4.4^{+1.1}_{-0.8}$ (SagDIG) to $9.6^{+2.5}_{-1.8}$ (Aquarius). Leo A and
SagDIG have lower stellar metallicities than Aquarius, and they also have
higher gas fractions, both of which would be expected if Aquarius were farther
along in its chemical evolution. The metallicity distribution of Leo A is
inconsistent with a Closed or Leaky Box model of chemical evolution, suggesting
that the galaxy was pre-enriched or acquired external gas during star
formation. The metallicities of stars increased steadily for all three
galaxies, but possibly at different rates. The [$\alpha$/Fe] ratios at a given
[Fe/H] are lower than that of the Sculptor dwarf spheroidal galaxy, which
indicates more extended star formation histories than Sculptor, consistent with
photometrically derived star formation histories. Overall, the bulk kinematic
and chemical properties for the late-forming dwarf galaxies do not diverge
significantly from those of less delayed dwarf galaxies, including dwarf
spheroidal galaxies.


title: Conversion of Internal Gravity Waves into Magnetic Waves

abstract:
  Asteroseismology probes the interiors of stars by studying oscillation modes
at a star's surface. Although pulsation spectra are well understood for
solar-like oscillators, a substantial fraction of red giant stars observed by
Kepler exhibit abnormally low-amplitude dipole oscillation modes. Fuller et al.
(2015) suggests this effect is produced by strong core magnetic fields that
scatter dipole internal gravity waves (IGWs) into higher multipole IGWs or
magnetic waves. In this paper, we study the interaction of IGWs with a magnetic
field to test this mechanism. We consider two background stellar structures:
one with a uniform magnetic field, and another with a magnetic field that
varies both horizontally and vertically. We derive analytic solutions to the
wave propagation problem and validate them with numerical simulations. In both
cases, we find perfect conversion from IGWs into magnetic waves when the IGWs
propagate into a region exceeding a critical magnetic field strength. Downward
propagating IGWs cannot reflect into upward propagating IGWs because their
vertical wavenumber never approaches zero. Instead, they are converted into
upward propagating slow (Alfvenic) waves, and we show they will likely
dissipate as they propagate back into weakly magnetized regions. Therefore,
strong internal magnetic fields can produce dipole mode suppression in red
giants, and gravity modes will likely be totally absent from the pulsation
spectra of sufficiently magnetized stars.


title:
Shocks and angular momentum flips: a different path to feeding the
  nuclear regions of merging galaxies

abstract:
  We study the dynamics of galaxy mergers, with emphasis on the gas feeding of
nuclear regions, using a suite of hydrodynamical simulations of galaxy
encounters. The high spatial and temporal resolution of the simulations allows
us to not only recover the standard picture of tidal-torque induced inflows,
but also to detail another, important feeding path produced by ram pressure.
The induced shocks effectively decouple the dynamics of the gas from that of
the stars, greatly enhancing the loss of gas angular momentum and leading to
increased central inflows. The ram-pressure shocks also cause, in many cases,
the entire galactic gas disc of the smaller galaxy to abruptly change its
direction of rotation, causing a complete "flip" and, several $10^8$ yr later,
a subsequent "counter-flip". This phenomenon results in the existence of
long-lived decoupled gas-stellar and stellar-stellar discs, which could hint at
a new explanation for the origin of some of the observed kinematically
decoupled cores/counter-rotating discs. Lastly, we speculate, in the case of
non-coplanar mergers, on the possible existence of a new class of remnant
systems similar to some of the observed X-shaped radio galaxies.


title:
Analytically determined topological phase diagram of the
  proximity-induced gap in diffusive n-terminal Josephson junctions

abstract:
  Multiterminal Josephson junctions have recently been proposed as a route to
artificially mimic topological matter with the distinct advantage that its
properties can be controlled via the superconducting phase difference, giving
rise to Weyl points in 4-terminal geometries. A key goal is to accurately
determine when the system makes a transition from a gapped to non-gapped state
as a function of the phase differences in the system, the latter effectively
playing the role of quasiparticle momenta in conventional topological matter.
We here determine the proximity gap phase diagram of diffusive n-terminal
Josephson junctions, both numerically and analytically, by identifying a class
of solutions to the Usadel equation at zero energy in the full proximity effect
regime. We present an analytical equation which provides the phase diagram for
an arbitrary number of terminals n. After briefly demonstrating the validity of
the analytical approach in the previously studied 2- and 3-terminal cases, we
focus on the 4-terminal case and map out the regimes where the electronic
excitations in the system are gapped and non-gapped, respectively,
demonstrating also in this case full agreement between the analytical and
numerical approach.


title:
Testing Hadronic Interactions at Ultrahigh Energies with Air Showers
  Measured by the Pierre Auger Observatory

abstract:
  Ultrahigh energy cosmic ray air showers probe particle physics at energies
beyond the reach of accelerators. Here we introduce a new method to test
hadronic interaction models without relying on the absolute energy calibration,
and apply it to events with primary energy 6-16 EeV (E_CM = 110-170 TeV), whose
longitudinal development and lateral distribution were simultaneously measured
by the Pierre Auger Observatory. The average hadronic shower is 1.33 +- 0.16
(1.61 +- 0.21) times larger than predicted using the leading LHC-tuned models
EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.


title: Partially Massless Higher-Spin Theory

abstract:
  We study a generalization of the D-dimensional Vasiliev theory to include a
tower of partially massless fields. This theory is obtained by replacing the
usual higher-spin algebra of Killing tensors on (A)dS with a generalization
that includes "third-order" Killing tensors. Gauging this algebra with the
Vasiliev formalism leads to a fully non-linear theory which is expected to be
UV complete, includes gravity, and can live on dS as well as AdS. The
linearized spectrum includes three massive particles and an infinite tower of
partially massless particles, in addition to the usual spectrum of particles
present in the Vasiliev theory, in agreement with predictions from a putative
dual CFT with the same symmetry algebra. We compute the masses of the particles
which are not fixed by the massless or partially massless gauge symmetry,
finding precise agreement with the CFT predictions. This involves computing
several dozen of the lowest-lying terms in the expansion of the trilinear form
of the enlarged higher-spin algebra. We also discuss nuances in the theory that
occur in specific dimensions; in particular, the theory dramatically truncates
in bulk dimensions D=3,5 and has non-diagonalizable mixings which occur in
D=4,7.


title:
Line-driven disk wind model for ultra-fast outflows in active galactic
  nuclei -- Scaling with luminosity

abstract:
  In order to reveal the origin of the ultra-fast outflows (UFOs) that are
frequently observed in active galactic nuclei (AGNs), we perform
two-dimensional radiation hydrodynamics simulations of the line-driven disk
winds, which are accelerated by the radiation force due to the spectral lines.
The line-driven winds are successfully launched for the range of $M_{\rm
BH}=10^{6-9}M_\odot$ and $\varepsilon$=0.1-0.5, and the resulting mass outflow
rate ($\dot{M_{\rm w}}$), momentum flux ($\dot{p_{\rm w}}$), and kinetic
luminosity ($\dot{E_{\rm w}}$) are in the region containing 90% of the
posterior probability distribution in the $\dot M_{\rm w}$-$L_{\rm bol}$ plane,
$\dot p_{\rm w}$-$L_{\rm bol}$ plane, and $\dot E_{\rm w}$-$L_{\rm bol}$ plane
shown in Gofford et al., where $M_{\rm BH}$ is the black hole mass,
$\varepsilon$ is the Eddington ratio, and $L_{\rm bol}$ is the bolometric
luminosity. The best-fitting relations in Gofford et al., $d\log\dot{M_{\rm
w}}/d\log{L_{\rm bol}}\sim 0.9$, $d\log\dot{p_{\rm w}}/d\log{L_{\rm bol}}\sim
1.2$, and $d\log\dot{E_{\rm w}}/d\log{L_{\rm bol}}\sim 1.5$, are roughly
consistent with our results, $d\log\dot{M_{\rm w}}/d\log{L_{\rm bol}}\sim 9/8$,
$d\log\dot{p_{\rm w}}/d\log{L_{\rm bol}}\sim 10/8$, and $d\log\dot{E_{\rm
w}}/d\log{L_{\rm bol}}\sim 11/8$. In addition, our model predicts that no UFO
features are detected for the AGNs with $\varepsilon \lesssim 0.01$, since the
winds do not appear. Also, only AGNs with $M_{\rm BH} \lesssim 10^8 M_\odot$
exhibit the UFOs when $\varepsilon \sim 0.025$. These predictions nicely agree
with the X-ray observations (Gofford et al.). These results support that the
line-driven disk wind is the origin of the UFOs.


title:
MeV-scale sterile neutrino decays at the Fermilab Short-Baseline
  Neutrino program

abstract:
  Nearly-sterile neutrinos with masses in the MeV range and below would be
produced in the beam of the Short-Baseline Neutrino (SBN) program at Fermilab.
In this article, we study the potential for SBN to discover these particles
through their subsequent decays in its detectors. We discuss the decays which
will be visible at SBN in a minimal and non-minimal extension of the Standard
Model, and perform simulations to compute the parameter space constraints which
could be placed in the absence of a signal. We demonstrate that the SBN program
can extend existing bounds on well constrained channels such as $N \rightarrow
\nu l^+ l^-$ and $N \rightarrow l^\pm \pi^\mp$ while, thanks to the strong
particle identification capabilities of liquid-Argon technology, also place
bounds on often neglected channels such as $N \rightarrow \nu\gamma$ and $N
\rightarrow \nu \pi^0$. Furthermore, we consider the phenomenological impact of
improved event timing information at the three detectors. As well as
considering its role in background reduction, we note that if the
light-detection systems in SBND and ICARUS can achieve nanosecond timing
resolution, the effect of finite sterile neutrino mass could be directly
observable, providing a smoking-gun signature for this class of models. We
stress throughout that the search for heavy nearly-sterile neutrinos is a
complementary new physics analysis to the search for eV-scale oscillations, and
would extend the BSM program of SBN while requiring no beam or detector
modifications.


title: Asteroseismic test of rotational mixing in low-mass white dwarfs

abstract:
  We exploit the recent discovery of pulsations in mixed-atmosphere (He/H),
extremely low-mass white dwarf precursors (ELM proto-WDs) to test the
proposition that rotational mixing is a fundamental process in the formation
and evolution of low-mass helium core white dwarfs. Rotational mixing has been
shown to be a mechanism able to compete efficiently against gravitational
settling, thus accounting naturally for the presence of He, as well as traces
of metals such as Mg and Ca, typically found in the atmospheres of ELM
proto-WDs. Here we investigate whether rotational mixing can maintain a
sufficient amount of He in the deeper driving region of the star, such that it
can fuel, through HeII-HeIII ionization, the observed pulsations in this type
of stars. Using state-of-the-art evolutionary models computed with MESA, we
show that rotational mixing can indeed explain qualitatively the very existence
and general properties of the known pulsating, mixed-atmosphere ELM proto-WDs.
Moreover, such objects are very likely to pulsate again during their final WD
cooling phase.


title: Experimental demonstration of non-bilocal quantum correlations

abstract:
  Quantum mechanics admits correlations that cannot be explained by local
realistic models. Those most studied are the standard local hidden variable
models, which satisfy the well-known Bell inequalities. To date, most works
have focused on bipartite entangled systems. Here, we consider correlations
between three parties connected via two independent entangled states. We
investigate the new type of so-called "bilocal" models, which correspondingly
involve two independent hidden variables. Such models describe scenarios that
naturally arise in quantum networks, where several independent entanglement
sources are employed. Using photonic qubits, we build such a linear three-node
quantum network and demonstrate non-bilocal correlations by violating a
Bell-like inequality tailored for bilocal models. Furthermore, we show that the
demonstration of non-bilocality is more noise-tolerant than that of standard
Bell non-locality in our three-party quantum network.


title:
Characterizing elusive, faint dusty star-forming galaxies: a lensed,
  optically undetected ALMA galaxy at z~3.3

abstract:
  We present the serendipitous ALMA detection of a faint submillimeter galaxy
(SMG) lensed by a foreground z~1 galaxy. By optimizing the source detection to
deblend the system, we accurately build the full spectral energy distribution
of the distant galaxy from the I814 band to radio wavelengths. It is extremely
red, with a I-K colour larger than 2.5. We estimate a photometric redshift of
3.28 and determine the physical parameters. The distant galaxy turns out to be
magnified by the foreground lens by a factor of ~1.5, which implies an
intrinsic Ks-band magnitude of ~24.5, a submillimeter flux at 870um of ~2.5 mJy
and a SFR of ~150-300Msun/yr, depending on the adopted tracer. These values
place our source towards the faint end of the distribution of observed SMGs,
and in particular among the still few faint SMGs with a fully characterized
spectral energy distribution, which allows us not only to accurately estimate
its redshift but also to measure its stellar mass and other physical
properties. The galaxy studied in this work is a representative of the
population of faint SMGs, of which only few objects are known to date, that are
undetected in optical and therefore are not typically accounted for when
measuring the cosmic star formation history (SFH). This faint galaxy population
thus likely represents an important and missing piece in our understanding of
the cosmic SFH. Its observation and characterization is of major importance to
achieve a solid picture of galaxy evolution.


title: Into the Bulk: A Covariant Approach

abstract:
  I propose a general, covariant way of defining when one region is "deeper in
the bulk" than another. This definition is formulated outside of an event
horizon (or in the absence thereof) in generic geometries; it may be applied to
both points and surfaces, and may be used to compare the depth of bulk points
or surfaces relative to a particular boundary subregion or relative to the
entire boundary. Using the recently proposed "lightcone cut" formalism, the
comparative depth between two bulk points can be determined from the
singularity structure of Lorentzian correlators in the dual field theory. I
prove that, by this definition, causal wedges of progressively larger regions
probe monotonically deeper in the bulk. The definition furthermore matches
expectations in pure AdS and in static AdS black holes with isotropic spatial
slices, where a well-defined holographic coordinate exists. In terms of
holographic RG flow, this new definition of bulk depth makes contact with
coarse-graining over both large distances and long time scales.


title: Flares, wind and nebulae: the 2015 December mini-outburst of V404 Cygni

abstract:
  After more than 26 years in quiescence, the black hole transient V404 Cyg
went into a luminous outburst in June 2015, and additional activity was
detected in late December of the same year. Here, we present an optical
spectroscopic follow-up of the December mini-outburst, together with X-ray,
optical and radio monitoring that spanned more than a month. Strong flares with
gradually increasing intensity are detected in the three spectral ranges during
the ~10 days following the Swift trigger. Our optical spectra reveal the
presence of a fast outflowing wind, as implied by the detection of a P-Cyg
profile (He I - 5876 A) with a terminal velocity of ~2500 km/s. Nebular-like
spectra -- with an H_alpha equivalent width of ~500 A -- are also observed. All
these features are similar to those seen during the main June 2015 outburst.
Thus, the fast optical wind simultaneous with the radio jet is most likely
present in every V404 Cyg outburst. Finally, we report on the detection of a
strong radio flare in late January 2016, when X-ray and optical monitoring had
stopped due to Sun constraints.


title: Entanglement area law in superfluid $^4$He

abstract:
  Area laws were first discovered by Bekenstein and Hawking, who found that the
entropy of a black hole grows proportional to its surface area, and not its
volume. Entropy area laws have since become a fundamental part of modern
physics, from the holographic principle in quantum gravity to ground state
wavefunctions of quantum matter, where entanglement entropy is generically
found to obey area law scaling. As no experiments are currently capable of
directly probing the entanglement area law in naturally occurring many-body
systems, evidence of its existence is based on studies of simplified theories.
Using new exact microscopic numerical simulations of superfluid $^4$He, we
demonstrate for the first time an area law scaling of entanglement entropy in a
real quantum liquid in three dimensions. We validate the fundamental principles
underlying its physical origin, and present an "entanglement equation of state"
showing how it depends on the density of the superfluid.


title: Aspects of general higher-order gravities

abstract:
  We study several aspects of higher-order gravities constructed from general
contractions of the Riemann tensor and the metric in arbitrary dimensions.
First, we use the fast-linearization procedure presented in arXiv:1607.06463 to
obtain the equations satisfied by the metric perturbation modes on a maximally
symmetric background in the presence of matter and to classify
$\mathcal{L}($Riemann$)$ theories according to their spectrum. Then, we
linearize all theories up to quartic order in curvature and use this result to
construct quartic versions of Einsteinian cubic gravity (ECG). In addition, we
show that the most general cubic gravity constructed in a dimension-independent
way and which does not propagate the ghost-like spin-2 mode (but can propagate
the scalar) is a linear combination of $f($Lovelock$)$ invariants, plus the ECG
term, plus a New ghost-free gravity term. Next, we construct the generalized
Newton potential and the Post-Newtonian parameter $\gamma$ for general
$\mathcal{L}($Riemann$)$ gravities in arbitrary dimensions, unveiling some
interesting differences with respect to the four-dimensional case. We also
study the emission and propagation of gravitational radiation from sources for
these theories in four dimensions, providing a generalized formula for the
power emitted. Finally, we review Wald's formalism for general
$\mathcal{L}($Riemann$)$ theories and construct new explicit expressions for
the relevant quantities involved. Many examples illustrate our calculations.


title:
Constraining the Thin Disc Initial Mass Function using Galactic
  Classical Cepheids

abstract:
  Context: The Initial Mass Function (IMF) plays a crucial role on galaxy
evolution and its implications on star formation theory make it a milestone for
the next decade. It is in the intermediate and high mass ranges where the
uncertainties of the IMF are larger. This is a major subject of debate and
analysis both for Galactic and extragalactic science. Aims: Our goal is to
constrain the IMF of the Galactic thin disc population using both Galactic
Classical Cepheids and Tycho-2 data. Methods: For the first time the
Besan\c{c}on Galaxy Model (BGM) has been used to characterise the Galactic
population of the Classical Cepheids. We have modified the age configuration in
the youngest populations of the BGM thin disc model to avoid artificial
discontinuities in the age distribution of the simulated Cepheids. Three
statistical methods, optimized for different mass ranges, have been developed
and applied to search for the best IMF that fits the observations. This
strategy allows us to quantify variations in the Star Formation History (SFH),
the stellar density at Sun position and the thin disc radial scale length. A
rigorous treatment of unresolved multiple stellar systems has been undertaken
adopting a spatial resolution according to the catalogues used. Results: For
intermediate masses, our study favours a composite field-star IMF slope of
$\alpha=3.2$ for the local thin disc, excluding flatter values such as the
Salpeter IMF ($\alpha=2.35$). Moreover, a constant Star Formation History is
definitively excluded, the three statistical methods considered here show that
it is inconsistent with the observational data. Conclusions: Using field stars
and Galactic Classical Cepheids, we have found, above $1M_\odot$, an IMF
steeper than the canonical stellar IMF of associations and young clusters. This
result is consistent with the predictions of the Integrated Galactic IMF.


title: Emergent Gravity from Vanishing Energy-Momentum Tensor

abstract:
  A constraint of vanishing energy-momentum tensor is motivated by a variety of
perspectives on quantum gravity. We demonstrate in a concrete example how this
constraint leads to a metric-independent theory in which quantum gravity
emerges as a nonperturbative artifact of regularization-scale physics. We
analyze a scalar theory similar to the Dirac-Born-Infeld (DBI) theory with
vanishing gauge fields, with the DBI Lagrangian modulated by a scalar
potential. In the limit of a large number of scalars, we explicitly demonstrate
the existence of a composite massless spin-2 graviton in the spectrum that
couples to matter as in Einstein gravity. We comment on the cosmological
constant problem and the generalization to theories with fermions and gauge
fields.


title: Partially Massless Higher-Spin Theory II: One-Loop Effective Actions

abstract:
  We continue our study of a generalization of the D-dimensional linearized
Vasiliev higher-spin equations to include a tower of partially massless (PM)
fields. We compute one-loop effective actions by evaluating zeta functions for
both the "minimal" and "non-minimal" parity-even versions of the theory.
Specifically, we compute the log-divergent part of the effective action in
odd-dimensional Euclidean AdS spaces for D=7 through 19 (dual to the a-type
conformal anomaly of the dual boundary theory), and the finite part of the
effective action in even-dimensional Euclidean AdS spaces for D=4 through 8
(dual to the free energy on a sphere of the dual boundary theory). We pay
special attention to the case D=4, where module mixings occur in the dual field
theory and subtlety arises in the one-loop computation. The results provide
evidence that the theory is UV complete and one-loop exact, and we conjecture
and provide evidence for a map between the inverse Newton's constant of the
partially massless higher-spin theory and the number of colors in the dual CFT.


title: The Cosmic Baryon Cycle and Galaxy Mass Assembly in the FIRE Simulations

abstract:
  We use cosmological simulations from the FIRE (Feedback In Realistic
Environments) project to study the baryon cycle and galaxy mass assembly for
central galaxies in the halo mass range $M_{\rm halo} \sim 10^{10} - 10^{13}
M_{\odot}$. By tracing cosmic inflows, galactic outflows, gas recycling, and
merger histories, we quantify the contribution of physically distinct sources
of material to galaxy growth. We show that in situ star formation fueled by
fresh accretion dominates the early growth of galaxies of all masses, while the
re-accretion of gas previously ejected in galactic winds often dominates the
gas supply for a large portion of every galaxy's evolution. Externally
processed material contributes increasingly to the growth of central galaxies
at lower redshifts. This includes stars formed ex situ and gas delivered by
mergers, as well as smooth intergalactic transfer of gas from other galaxies,
an important but previously under-appreciated growth mode. By $z=0$, wind
transfer, i.e. the exchange of gas between galaxies via winds, can dominate gas
accretion onto $\sim L^{*}$ galaxies over fresh accretion and standard wind
recycling. Galaxies of all masses re-accrete >50% of the gas ejected in winds
and recurrent recycling is common. The total mass deposited in the
intergalactic medium per unit stellar mass formed increases in lower mass
galaxies. Re-accretion of wind ejecta occurs over a broad range of timescales,
with median recycling times ($\sim 100-350$ Myr) shorter than previously found.
Wind recycling typically occurs at the scale radius of the halo, independent of
halo mass and redshift, suggesting a characteristic recycling zone around
galaxies that scales with the size of the inner halo and the galaxy's stellar
component.


title:
A Triple Protostar System Formed via Fragmentation of a Gravitationally
  Unstable Disk

abstract:
  Binary and multiple star systems are a frequent outcome of the star formation
process, and as a result, almost half of all sun-like stars have at least one
companion star. Theoretical studies indicate that there are two main pathways
that can operate concurrently to form binary/multiple star systems: large scale
fragmentation of turbulent gas cores and filaments or smaller scale
fragmentation of a massive protostellar disk due to gravitational instability.
Observational evidence for turbulent fragmentation on scales of $>$1000~AU has
recently emerged. Previous evidence for disk fragmentation was limited to
inferences based on the separations of more-evolved pre-main sequence and
protostellar multiple systems. The triple protostar system L1448 IRS3B is an
ideal candidate to search for evidence of disk fragmentation. L1448 IRS3B is in
an early phase of the star formation process, likely less than 150,000 years in
age, and all protostars in the system are separated by $<$200~AU. Here we
report observations of dust and molecular gas emission that reveal a disk with
spiral structure surrounding the three protostars. Two protostars near the
center of the disk are separated by 61 AU, and a tertiary protostar is
coincident with a spiral arm in the outer disk at a 183 AU separation. The
inferred mass of the central pair of protostellar objects is $\sim$1 M$_{sun}$,
while the disk surrounding the three protostars has a total mass of $\sim$0.30
M$_{\sun}$. The tertiary protostar itself has a minimum mass of $\sim$0.085
M$_{sun}$. We demonstrate that the disk around L1448 IRS3B appears susceptible
to disk fragmentation at radii between 150~AU and 320~AU, overlapping with the
location of the tertiary protostar. This is consistent with models for a
protostellar disk that has recently undergone gravitational instability,
spawning one or two companion stars.


title:
Strong lensing signatures of luminous structure and substructure in
  early-type galaxies

abstract:
  The arrival times, positions, and fluxes of multiple images in strong lens
systems can be used to infer the presence of dark subhalos in the deflector,
and thus test predictions of cold dark matter models. However, gravitational
lensing does not distinguish between perturbations to a smooth gravitational
potential arising from baryonic and non-baryonic mass. In this work, we
quantify the extent to which the stellar mass distribution of a deflector can
reproduce flux ratio and astrometric anomalies typically associated with the
presence of a dark matter subhalo. Using Hubble Space Telescope images of
nearby galaxies, we simulate strong lens systems with real distributions of
stellar mass as they would be observed at redshift $z_d=0.5$. We add a dark
matter halo and external shear to account for the smooth dark matter field,
omitting dark substructure, and use a Monte Carlo procedure to characterize the
distributions of image positions, time delays, and flux ratios for a compact
background source of diameter 5 pc. By convolving high-resolution images of
real galaxies with a Gaussian PSF, we simulate the most detailed smooth
potential one could construct given high quality data, and find scatter in flux
ratios of $\approx 10\%$, which we interpret as a typical deviation from a
smooth potential caused by large and small scale structure in the lensing
galaxy. We demonstrate that the flux ratio anomalies arising from galaxy-scale
baryonic structure can be minimized by selecting the most massive and round
deflectors, and by simultaneously modeling flux ratio and astrometric data.


title: BMS Particles in Three Dimensions

abstract:
  This thesis is devoted to the group-theoretic aspects of three-dimensional
quantum gravity on Anti-de Sitter and Minkowskian backgrounds. In particular we
describe the relation between unitary representations of asymptotic symmetry
groups and gravitational perturbations around a space-time metric. In the
asymptotically flat case this leads to "BMS particles", representing standard
relativistic particles dressed with gravitational degrees of freedom accounted
for by coadjoint orbits of the Virasoro group. Their thermodynamics are
described by BMS characters, which coincide with gravitational one-loop
partition functions. We also extend these considerations to higher-spin
theories and supergravity.

categories: hep-th gr-qc math-ph math.GR math.MP math.RT


title: Quantum phase transition in many-flavor supersymmetric QED$_{3}$

abstract:
  We study $\mathcal{N}=4$ supersymmetric QED in three dimensions, on a
three-sphere, with 2N massive hypermultiplets and a Fayet-Iliopoulos parameter.
We identify the exact partition function of the theory with a conical (Mehler)
function. This implies a number of analytical formulas, including a recurrence
relation and a second-order differential equation, associated with an
integrable system. In the large N limit, the theory undergoes a second-order
phase transition on a critical line in the parameter space. We discuss the
critical behavior and compute the two-point correlation function of a gauge
invariant mass operator, which is shown to diverge as one approaches
criticality from the subcritical phase. Finally, we comment on the asymptotic
1/N expansion and on mirror symmetry.


title:
Ab initio Simulations of a Supernova Driven Galactic Dynamo in an
  Isolated Disk Galaxy

abstract:
  We study the magnetic field evolution of an isolated spiral galaxy, using
isolated Milky Way-mass galaxy formation simulations and a novel prescription
for magnetohydrodynamic (MHD) supernova feedback. Our main result is that a
galactic dynamo can be seeded and driven by supernova explosions, resulting in
magnetic fields whose strength and morphology is consistent with observations.
In our model, supernovae supply thermal energy, and a low level magnetic field
along with their ejecta. The thermal expansion drives turbulence, which serves
a dual role by efficiently mixing the magnetic field into the interstellar
medium, and amplifying it by means of turbulent dynamo. The computational
prescription for MHD supernova feedback has been implemented within the
publicly available ENZO code, and is fully described in this paper. This
improves upon ENZO's existing modules for hydrodynamic feedback from stars and
active galaxies. We find that the field attains $\mu G$-levels over Gyr-time
scales throughout the disk. The field also develops large-scale structure,
which appears to be correlated with the disk's spiral arm density structure. We
find that seeding of the galactic dynamo by supernova ejecta predicts a
persistent correlation between gas metallicity and magnetic field strength. We
also generate all-sky maps of the Faraday rotation measure from the
simulation-predicted magnetic field, and present a direct comparison with
observations.


title: Contextuality as a resource for models of quantum computation on qubits

abstract:
  A central question in quantum computation is to identify the resources that
are responsible for quantum speed-up. Quantum contextuality has been recently
shown to be a resource for quantum computation with magic states for odd-prime
dimensional qudits and two-dimensional systems with real wavefunctions. The
phenomenon of state-independent contextuality poses a priori an obstruction to
characterizing the case of regular qubits, the fundamental building block of
quantum computation. Here, we establish contextuality of magic states as a
necessary resource for a large class of quantum computation schemes on qubits.
We illustrate our result with a concrete scheme related to measurement-based
quantum computation.


title: Tracing the pressure of the gluon plasma

abstract:
  Being interested in how a strongly coupled system approaches asymptotic
freedom, we re-examine existing precision lattice QCD results for thermodynamic
properties of the gluon plasma in a large temperature range. We discuss and
thoroughly test the applicability of perturbative results, on which grounds we
then infer that the pressure and other bulk properties approach the free limit
somewhat slower than previously thought. We also revise the value of the first
non-perturbative coefficient in the weak-coupling expansion.


title: Charm Quark Mass with Calibrated Uncertainty

abstract:
  We determine the charm quark mass $\hat{m}_c$ from QCD sum rules of moments
of the vector current correlator calculated in perturbative QCD at ${\cal O}
(\hat\alpha_s^3)$. Only experimental data for the charm resonances below the
continuum threshold are needed in our approach, while the continuum
contribution is determined by requiring self-consistency between various sum
rules. Existing data from the continuum region can then be used to bound the
theoretic uncertainty. Our result is $\hat{m}_c(\hat{m}_c) = 1272 \pm 8$~MeV
for $\hat\alpha_s(M_Z) = 0.1182$.


title:
Magnetorotational instability in neutron star mergers: impact of
  neutrinos

abstract:
  The merger of two neutron stars may give birth to a long-lived hypermassive
neutron star. If it harbours a strong magnetic field of magnetar strength, its
spin-down could explain several features of short gamma-ray burst afterglows.
The magnetorotational instability (MRI) has been proposed as a mechanism to
amplify the magnetic field to the required strength. Previous studies have,
however, neglected neutrinos, which may have an important impact on the MRI by
inducing a viscosity and drag. We investigate the impact of these neutrino
effects on the linear growth of the MRI by applying a local stability analysis
to snapshots of a neutron star merger simulation. We find that neutrinos have a
significant impact inside the hypermassive neutron star, but have at most a
marginal effect in the torus surrounding it. Inside the hypermassive neutron
star, the MRI grows in different regimes depending on the radius and on the
initial magnetic field strength. For magnetic fields weaker than
$10^{13}-10^{14}\,{\rm G}$, the growth rate of the MRI is significantly reduced
due to the presence of neutrinos. We conclude that neutrinos should be taken
into account when studying the growth of the MRI from realistic initial
magnetic fields. Current numerical simulations, which neglect neutrino
viscosity, are only consistent, i.e. in the adopted ideal regime, if they start
from artificially strong initial magnetic fields above $\sim10^{14}\,{\rm G}$.
One should be careful when extrapolating these results to lower initial
magnetic fields, where the MRI growth is strongly affected by neutrino
viscosity or drag.


title: Iterated Gilbert Mosaics and Poisson Tropical Plane Curves

abstract:
  We propose an iterated version of the Gilbert model, which results in a
sequence of random mosaics of the plane. We prove that under appropriate
scaling, this sequence of mosaics converges to that obtained by a classical
Poisson line process with explicit cylindrical measure. Our model arises from
considerations on tropical plane curves, which are zeros of random tropical
polynomials in two variables. In particular, the iterated Gilbert model
convergence allows one to derive a scaling limit for Poisson tropical plane
curves. Our work raises a number of open questions at the intersection of
stochastic and tropical geometry.


title:
Optimal model order reduction with the Steiglitz-McBride method for
  open-loop data

abstract:
  In system identification, it is often difficult to find a physical intuition
to choose a noise model structure. The importance of this choice is that, for
the prediction error method (PEM) to provide asymptotically efficient
estimates, the model orders must be chosen according to the true system.
However, if only the plant estimates are of interest and the experiment is
performed in open loop, the noise model may be over-parameterized without
affecting the asymptotic properties of the plant. The limitation is that, as
PEM suffers in general from non-convexity, estimating an unnecessarily large
number of parameters will increase the chances of getting trapped in local
minima. To avoid this, a high order ARX model can first be estimated by least
squares, providing non-parametric estimates of the plant and noise model. Then,
model order reduction can be used to obtain a parametric model of the plant
only. We review existing methods to perform this, pointing out limitations and
connections between them. Then, we propose a method that connects favorable
properties from the previously reviewed approaches. We show that the proposed
method provides asymptotically efficient estimates of the plant with open loop
data. Finally, we perform a simulation study, which suggests that the proposed
method is competitive with PEM and other similar methods.


title:
On Multihop Weibull-Fading Communications: Performance Analysis
  Framework and Applications

abstract:
  The paper presents a comprehensive closed-form performance analysis framework
for multihop communications over Weibull fading channels. The analyzed scheme
consists basically of multiple regenerative relays with generalized high-order
quadrature amplitude modulation (M-QAM) transmissions. To take into
consideration the channel fading in the mmWave range, we adopt the advocated
Weibull model for its flexible ability to cover different channel conditions.
The end-to-end performance is evaluated in terms of outage probability, bit
error probability (BER), symbol error probability (SER), block error rate
(BLER), ergodic capacity, and energy efficiency (EE). For all the metrics, we
present exact closed-form expressions along with their asymptotic behavior,
some in terms of generalized hypergeometric functions. Based on the obtained
analytical results, we also present a practical application, we derive two BER-
and EE-optimal transmit power allocation strategies, and we discuss the
resulting performance gains. The exactness of our analysis is illustrated by
numerical examples, and assessed via Monte-Carlo simulations for different
system and channel parameters. Finally, as a secondary contribution, noting the
increasing popularity of Fox's H and bivariate H functions, we provide new and
generalized codes for computing these functions which are of practical utility
in different contexts.


title: Heavy quark production at an Electron-Ion Collider

abstract:
  An Electron-Ion Collider (EIC) with center-of-mass energies sqrt(s_{eN}) ~
20-100 GeV and luminosity L ~ 10^{34} cm^{-2} s^{-1} would offer new
opportunities to study heavy quark production in high-energy electron or photon
scattering on protons and nuclei. We report about an R&D project exploring the
feasibility of direct measurements of nuclear gluon densities at large x
(gluonic EMC effect, antishadowing) using open charm production at EIC. We
describe the charm production rates and angle-momentum distributions at large x
and discuss methods of charm reconstruction using next-generation detector
capabilities (pi/K identification, vertex reconstruction). The results can be
used also for other physics applications of heavy quark production at EIC
(fragmentation functions, jets, heavy quark propagation in nuclei).


title: Higgs Effective Field Theories - Systematics and Applications

abstract:
  We discuss effective field theories (EFTs) for the Higgs particle, which is
not necessarily the Higgs of the Standard Model. We distinguish two different
consistent expansions: EFTs that describe decoupling new-physics effects and
EFTs that describe non-decoupling new-physics effects. We briefly discuss the
first case, the SM-EFT. The focus of this thesis is on the non-decoupling EFTs.
We argue that the loop expansion is the consistent expansion in the second
case. We introduce the concept of chiral dimensions, equivalent to the loop
expansion. Using the chiral dimensions, we expand the electroweak chiral
Lagrangian up to next-to-leading order,
$\mathcal{O}(f^{2}/\Lambda^{2})=\mathcal{O}(1/16\pi^{2})$.
  We then compare the decoupling and the non-decoupling EFT. We also consider
scenarios in which the new-physics sector is non-decoupling at a scale $f$, far
above the electroweak-scale $v$. We discuss the relevance of the resulting
double expansion in $\xi=v^{2}/f^{2}$ and $f^{2}/\Lambda^{2}$ for the data
analysis at the LHC.
  In the second part, we discuss the applications of the EFTs, especially of
the electroweak chiral Lagrangian. First, we connect the EFT with explicit
models of new physics. We show how different regions of the parameter space of
the same model generate a decoupling and a non-decoupling EFT.
  Second, we use the expansion at leading order to describe the current LHC
Higgs data. We show how the current parametrization of the Higgs data, the
$\kappa$-framework, can be justified quantum field theoretically by the EFT. We
fit the data of Run-1 (2010--2013). The effective Lagrangian describing this
data can be reduced to six free parameters. The result of this fit is
consistent with the SM, but it has statistical uncertainties of about ten
percent.


title:
Response of the Martian Ionosphere to Solar Activity including SEPs and
  ICMEs in a two week period starting on 25 February 2015

abstract:
  In a two-week period between February and March of 2015, a series of
interplanetary coronal mass ejections (ICMEs) and (solar energetic particles)
SEPs made contact with Mars. The interactions were observed by several
spacecraft, including Mars Express (MEX), Mars Atmosphere and Volatile
Evolution Mission (MAVEN), and Mars Odyssey (MO). The ICME disturbances were
characterized by an increase in ion speed, plasma temperature, magnetic field
magnitude, and energetic electron flux. Furthermore, increased solar wind
density and speeds, unusually high local electron densities and high flow
velocities were detected on the nightside at high altitudes during the March
8th event. These effects are thought to be due to the transport of ionospheric
plasma away from Mars. The peak electron density at periapsis shows a
substantial increase, reaching number densities about 2.7 x 104 cm-3 during the
second ICME in the deep nightside, which corresponds to an increase in the
MOHigh-Energy Neutron Detector flux, suggesting an increase in the ionization
of the neutral atmosphere due to the high intensity of charged particles. SEPs
show a substantial enhancement before the shock of fourth ICME causing impact
ionization and absorption of the surface echo intensity which drops to the
noise levels. Moreover, the peak ionospheric density exhibits a discrete
enhancement over a period of about 30 hrs around the same location, which maybe
due to impact ionization. Ion escape rates at this time are calculated to be in
the order of 1025 - 1026 s-1, consistent with MAVEN results, but somewhat
higher.


title:
The Stability Spectrum for Elliptic Solutions to the Focusing NLS
  Equation

abstract:
  We present an analysis of the stability spectrum of all stationary
elliptic-type solutions to the focusing Nonlinear Schr\"{o}dinger equation
(NLS). An analytical expression for the spectrum is given. From this
expression, various quantitative and qualitative results about the spectrum are
derived. Specifically, the solution parameter space is shown to be split into
four regions of distinct qualitative behavior of the spectrum. Additional
results on the stability of solutions with respect to perturbations of an
integer multiple of the period are given, as well as a procedure for
approximating the greatest real part of the spectrum.


title:
Magnetic Flux Cancellation as the Trigger of Solar Quiet-Region Coronal
  Jets

abstract:
  We report observations of ten random on-disk solar quiet region coronal jets
found in high resolution Extreme Ultraviolet (EUV) images from the Solar
Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and having good
coverage in magnetograms from the SDO/Helioseismic and Magnetic Imager (HMI).
Recent studies show that coronal jets are driven by the eruption of a
small-scale filament (called a minifilament). However the trigger of these
eruptions is still unknown. In the present study we address the question: what
leads to the jet-driving minifilament eruptions? The EUV observations show that
there is a cool-transition-region-plasma minifilament present prior to each jet
event and the minifilament eruption drives the jet. By examining pre-jet
evolutionary changes in the line-of-sight photospheric magnetic field we
observe that each pre-jet minifilament resides over the neutral line between
majority-polarity and minority-polarity patches of magnetic flux. In each of
the ten cases, the opposite-polarity patches approach and merge with each other
(flux reduction between 21 and 57%). After several hours, continuous flux
cancellation at the neutral line apparently destabilizes the field holding the
cool-plasma minifilament to erupt and undergo internal reconnection, and
external reconnection with the surrounding-coronal field. The external
reconnection opens the minifilament field allowing the minifilament material to
escape outwards, forming part of the jet spire. Thus we found that each of the
ten jets resulted from eruption of a minifilament following flux cancellation
at the neutral line under the minifilament. These observations establish that
magnetic flux cancellation is usually the trigger of quiet region coronal jet
eruptions.


title:
i-process nucleosynthesis and mass retention efficiency in He-shell
  flash evolution of rapidly accreting white dwarfs

abstract:
  Based on stellar evolution simulations, we demonstrate that rapidly accreting
white dwarfs in close binary systems are an astrophysical site for the
intermediate neutron-capture process. During recurrent and very strong He-shell
flashes in the stable H-burning accretion regime H-rich material enters the
He-shell flash convection zone. $^{12}$C(p,$\gamma)^{13}$N reactions release
enough energy to potentially impact convection, and i process is activated
through the $^{13}$C($\alpha$,n)$^{16}$O reaction. The H-ingestion flash may
not cause a split of the convection zone as it was seen in simulations of
He-shell flashes in post-AGB and low-Z AGB stars. We estimate that for the
production of first-peak heavy elements this site can be of similar importance
for galactic chemical evolution as the s-process production by low-mass AGB
stars. The He-shell flashes result in the expansion and, ultimately, ejection
of the accreted and then i-process enriched material, via super-Eddington
luminosity winds or Roche-lobe overflow. The white dwarf models do not retain
any significant amount of the accreted mass, with a He retention efficiency of
$\leq 10\%$ depending on mass and convective boundary mixing assumptions. This
makes the evolutionary path of such systems to supernova Ia explosion highly
unlikely.


title:
Rigorous derivation of nonlinear Dirac equations for wave propagation in
  honeycomb structures

abstract:
  We consider a nonlinear Schroedinger equation in two spatial dimensions
subject to a periodic honeycomb lattice potential. Using a multi-scale
expansion together with rigorous error estimates, we derive an effective model
of nonlinear Dirac type. The latter describes the propagation of slowly
modulated, weakly nonlinear waves spectrally localized near a Dirac point.


title: An efficient approximation for point-set diameter in higher dimensions

abstract:
  In this paper, we study the problem of computing the diameter of a set of $n$
points in $d$-dimensional Euclidean space for a fixed dimension $d$, and
propose a new $(1+\varepsilon)$-approximation algorithm with $O(n+
1/\varepsilon^{d-1})$ time and $O(n)$ space, where $0 < \varepsilon\leqslant
1$. We also show that the proposed algorithm can be modified to a
$(1+O(\varepsilon))$-approximation algorithm with $O(n+
1/\varepsilon^{\frac{2d}{3}-\frac{1}{3}})$ running time. These results provide
some improvements in comparison with existing algorithms in terms of simplicity
and data structure.


title: Anomalous Diffusion and Stress Relaxation in Surfactant Micelles

abstract:
  We present the first molecular dynamics study to probe the mechanisms of
anomalous diffusion in cationic surfactant micelles in the presence of explicit
salt and solvent-mediated interactions. Simulations show that when the counter
ion density increases, saddle-shaped interfaces manifest leading to the
formation of branched structures. In experiments, branched structures exhibit
lower viscosity as compared to linear and wormlike micelles, presumably due to
stress relaxation arising from the sliding motion of branches along the main
chain. Our simulations provide conclusive evidence and a mechanism of branch
motion and stress relaxation in micellar fluids. Further, depending upon the
surfactant and salt concentrations, which in turn determine the microstructure,
we observe normal, subdiffusive and superdiffusive motion of surfactants.
Specifically, superdiffusive behavior is associated with branch sliding,
breakage and recombination of micelle fragments as well as constraint release
in entangled systems.


title: The topology and geometry of automorphism groups of free groups

abstract:
  In the 1970s Stallings showed that one could learn a great deal about free
groups and their automorphisms by viewing the free groups as fundamental groups
of graphs and modeling their automorphisms as homotopy equivalences of graphs.
Further impetus for using graphs to study automorphism groups of free groups
came from the introduction of a space of graphs, now known as Outer space, on
which the group $Out(F_n)$ acts nicely. The study of Outer space and its
$Out(F_n)$ action continues to give new information about the structure of
$Out(F_n)$, but has also found surprising connections to many other groups,
spaces and seemingly unrelated topics, from phylogenetic trees to cyclic
operads and modular forms. In this talk I will highlight various ways these
ideas are currently evolving.


title: Diphoton production in lead-lead and proton-proton UPC

abstract:
  We discuss diphoton semi(exclusive) production in ultraperipheral $PbPb$
collisions at energy of $\sqrt{s_{NN}}=$ 5.5 TeV (LHC). The nuclear
calculations are based on equivalent photon approximation in the impact
parameter space. The cross sections for elementary $\gamma \gamma \to \gamma
\gamma$ subprocess are calculated including three different mechanisms: box
diagrams with leptons and quarks in the loops, a VDM-Regge contribution with
virtual intermediate hadronic excitations of the photons and the two-gluon
exchange contribution (formally three-loops) to elastic photon-photon
scattering in the high-energy approximation. We got relatively high cross
sections in $PbPb$ collisions ($306$ nb). This opens a possibility to study the
$\gamma \gamma \to \gamma \gamma$ (quasi)elastic scattering at the LHC. We find
that the cross section for elastic $\gamma\gamma$ scattering could be measured
in the lead-lead collisions for the diphoton invariant mass up to
$W_{\gamma\gamma} \approx 15-20$ GeV. We identify region(s) of phase space
where the two-gluon exchange contribution becomes important ingredient compared
to box and nonperturbative VDM-Regge mechanisms. We perform a similar analysis
for the $pp \to pp\gamma\gamma$ reaction at energy of $\sqrt{s_{NN}}=7$ and
$100$ TeV.


title:
Linear stability of Schwarzschild spacetime subject to axial
  perturbations

abstract:
  In this paper, we address the issue of linear stability of Schwarzschild
space- time subject to certain axisymmetric perturbations. In particular, we
prove that associ- ated solutions to the linearized vacuum Einstein equations
centered at a Schwarzschild metric, with suitably regular initial data, decay
to a linearized Kerr metric. Our method employs a complex line bundle
interpretation applied to a connection-level object, allow- ing for direct
analysis of this connection-level object by the linearized Einstein equations,
in contrast with the recent breakthrough of Dafermos-Holzegel-Rodnianski.


title: Cosmic vacuum energy decay and creation of cosmic matter

abstract:
  In the more recent literature on cosmological evolutions of the universe the
cosmic vacuum energy has become a non-renouncable ingredient. The cosmological
constant $\Lambda$, first invented by Einstein, but later also rejected by him,
presently experiences an astonishing revival. Interestingly enough it acts,
like a constant vacuum energy density would also do. Namely, it has an
accelerating action on cosmic dynamics without which, as it appears, presently
obtained cosmological data cannot be conciliated with theory. As we are going
to show in this review, however, the concept of a constant vacuum energy
density is unsatisfactory for very basic reasons, since it would claim for a
physical reality that acts upon spacetime and matter dynamics without itself
being acted upon by spacetime or matter.


title:
Constraining the generalized uncertainty principle with the
  gravitational wave event GW150914

abstract:
  In this letter, we show that the dimensionless parameter in the generalized
uncertainty principle (GUP) can be constrained by the gravitational wave event
GW150914, which was discovered by the LIGO Scientific and Virgo Collaborations.
Firstly, according to the Heisenberg uncertainty principle (HUP) and the data
of gravitational wave event GW150914, we derive the standard energy-momentum
dispersion relation and calculate the difference between the propagation speed
of gravitons and the speed of light, i.e., $\Delta \upsilon$. Next, using two
proposals regarding the GUP, we also generalize our study to the quantum
gravity case and obtain the modified speed of gravitons. Finally, based on the
modified speed of gravitons and $\Delta \upsilon$, the improved upper bounds on
the GUP parameters are obtained. The results show that the upper limits of the
GUP parameters $\beta_0$ and $\alpha_0$ are $2.3 \times 10^ {60}$ and $1.8
\times 10^{20}$.


title:
First principles study of band line up at defective metal-oxide
  interface: oxygen point defects at Al/SiO_2 interface

abstract:
  The dielectric breakdown at metal-oxide interfaces is a critical electronic
device failure mechanism. Electronic tunneling through dielectric layers is a
well-accepted explanation for this phenomenon. Theoretical band alignment
studies, providing information about tunneling, have already been conducted in
the literature for metal-oxide interfaces. However, most of the time materials
were assumed defect free. Oxygen vacancies being very common in oxides, their
effect on band lineup is of prime importance in understanding electron
tunneling in realistic materials and devices. This work explores the effect of
oxygen vacancy and oxygen di-vacancy at the Al/SiO2 interface on the band line
up within Density Functional Theory using PBE0 hybrid exchange and correlation
functional. It is found that the presence of defects at the interface, and
their charge state, strongly alters the band line up.


title:
Computations of the Mertens Function and Improved Bounds on the Mertens
  Conjecture

abstract:
  The Mertens function is defined as $M(x) = \sum_{n \leq x} \mu(n)$, where
$\mu(n)$ is the M\"obius function. The Mertens conjecture states
$|M(x)/\sqrt{x}| < 1$ for $x > 1$, which was proven false in 1985 by showing
$\liminf M(x)/\sqrt{x} < -1.009$ and $\limsup M(x)/\sqrt{x} > 1.06$. The same
techniques used were revisited here with present day hardware and algorithms,
giving improved lower and upper bounds of $-1.837625$ and $1.826054$. In
addition, $M(x)$ was computed for all $x \leq 10^{16}$, recording all extrema,
all zeros, and $10^8$ values sampled at a regular interval. Lastly, an
algorithm to compute $M(x)$ in $O(x^{2/3+\varepsilon})$ time was used on all
powers of two up to $2^{73}$.


title:
Functional architecture and global properties of the Corynebacterium
  glutamicum regulatory network: novel insights from a dataset with a high
  genomic coverage

abstract:
  Corynebacterium glutamicum is a Gram-positive, anaerobic, rod-shaped soil
bacterium able to grow on a diversity of carbon sources like sugars and organic
acids. It is a biotechnological relevant organism because of its highly
efficient ability to biosynthesize amino acids, such as L-glutamic acid and
L-lysine. Here, we reconstructed the most complete C. glutamicum regulatory
network to date and comprehensively analyzed its global organizational
properties, systems-level features and functional architecture. Our analyses
show the tremendous power of Abasy Atlas to study the functional organization
of regulatory networks. We created two models of the C. glutamicum regulatory
network: all-evidences (containing both weak and strong supported interactions,
genomic coverage = 73%) and strongly-supported (only accounting for strongly
supported evidences, genomic coverage = 71%). Using state-of-the-art
methodologies, we prove that power-law behaviors truly govern the connectivity
and clustering coefficient distributions. We found a non-previously reported
circuit motif that we named complex feed-forward motif. We highlighted the
importance of feedback loops for the functional architecture, beyond whether
they are statistically over-represented or not in the network. We show that the
previously reported top-down approach is inadequate to infer the hierarchy
governing a regulatory network because feedback bridges different hierarchical
layers, and the top-down approach disregards the presence of intermodular genes
shaping the integration layer. Our findings all together further support a
diamond-shaped, three-layered hierarchy exhibiting some feedback between
processing and coordination layers, which is shaped by four classes of
systems-level elements: global regulators, locally autonomous modules, basal
machinery and intermodular genes.


title:
Josephson current signatures of the Majorana flat bands on the surface
  of time-reversal-invariant Weyl and Dirac semimetals

abstract:
  A linear Josephson junction mediated by the surface states of a
time-reversal-invariant Weyl or Dirac semimetal localizes Majorana flat bands
protected by the time-reversal symmetry. We show that as a result, the
Josephson current exhibits a discontinuous jump at $\pi$ phase difference which
can serve as an experimental signature of the Majorana bands. The magnitude of
the jump scales proportionally to the junction width and the momentum space
distance between the Weyl nodes. It also exhibits a characteristic dependence
on the junction orientation. We demonstrate that the jump is robust against the
effects of non-zero temperature and weak non-magnetic disorder.


title:
The most massive galaxies in clusters are already fully grown at $z \sim
  0.5$

abstract:
  By constructing scaling relations for galaxies in the massive cluster
MACSJ0717.5 at $z=0.545$ and comparing with those of Coma, we model the
luminosity evolution of the stellar populations and the structural evolution of
the galaxies. We calculate magnitudes, surface brightnesses and effective radii
using HST/ACS images and velocity dispersions using Gemini/GMOS spectra, and
present a catalogue of our measurements for 17 galaxies. We also generate
photometric catalogues for $\sim 3000$ galaxies from the HST imaging. With
these, we construct the colour-magnitude relation, the fundamental plane, the
mass-to-light versus mass relation, the mass-size relation and the
mass-velocity dispersion relation for both clusters. We present a new, coherent
way of modelling these scaling relations simultaneously using a simple physical
model in order to infer the evolution in luminosity, size and velocity
dispersion as a function of redshift, and show that the data can be fully
accounted for with this model. We find that (a) the evolution in size and
velocity dispersion undergone by these galaxies between $z \sim 0.5$ and $z
\sim 0$ is mild, with $R_e(z) \sim (1+z)^{-0.40\pm0.32}$ and $\sigma(z) \sim
(1+z)^{0.09 \pm 0.27}$, and (b) the stellar populations are old, $\sim 10$ Gyr,
with a $\sim 3$ Gyr dispersion in age, and are consistent with evolving purely
passively since $z \sim 0.5$ with $\Delta \log M/L_B = -0.55_{-0.07}^{+0.15}
z$. The implication is that these galaxies formed their stars early and
subsequently grew dissipationlessly so as to have their mass already in place
by $z \sim 0.5$, and suggests a dominant role for dry mergers, which may have
accelerated the growth in these high-density cluster environments.


title: Evolution Of Binary Supermassive Black Holes In Rotating Nuclei

abstract:
  Interaction of a binary supermassive black hole with stars in a galactic
nucleus can result in changes to all the elements of the binary's orbit,
including the angles that define its orientation. If the nucleus is rotating,
the orientation changes can be large, causing large changes in the binary's
orbital eccentricity as well. We present a general treatment of this problem
based on the Fokker-Planck equation for f, defined as the probability
distribution for the binary's orbital elements. First- and second-order
diffusion coefficients are derived for the orbital elements of the binary using
numerical scattering experiments, and analytic approximations are presented for
some of these coefficients. Solutions of the Fokker-Planck equation are then
derived under various assumptions about the initial rotational state of the
nucleus and the binary hardening rate. We find that the evolution of the
orbital elements can become qualitatively different when we introduce nuclear
rotation: 1) the orientation of the binary's orbit evolves toward alignment
with the plane of rotation of the nucleus; 2) binary orbital eccentricity
decreases for aligned binaries and increases for counter-aligned ones. We find
that the diffusive (random-walk) component of a binary's evolution is small in
nuclei with non-negligible rotation, and we derive the time-evolution equations
for the semimajor axis, eccentricity and inclination in that approximation. The
aforementioned effects could influence gravitational wave production as well as
the relative orientation of host galaxies and radio jets.


title:
Assembly of hard spheres in a cylinder: a computational and experimental
  study

abstract:
  Hard spheres are an important benchmark of our understanding of natural and
synthetic systems. In this work, colloidal experiments and Monte Carlo
simulations examine the equilibrium and out-of-equilibrium assembly of hard
spheres of diameter $\sigma$ within cylinders of diameter $\sigma\leq D\leq
2.82\sigma$. Although in such a system phase transitions formally do not exist,
marked structural crossovers are observed. In simulations, we find that the
resulting pressure-diameter structural diagram echoes the densest packing
sequence obtained at infinite pressure in this range of $D$. We also observe
that the out-of-equilibrium self-assembly depends on the compression rate. Slow
compression approximates equilibrium results, while fast compression can skip
intermediate structures. Crossovers for which no continuous line-slip exists
are found to be dynamically unfavorable, which is the source of this
difference. Results from colloidal sedimentation experiments at high P\'eclet
number are found to be consistent with the results of fast compressions, as
long as appropriate boundary conditions are used. The similitude between
compression and sedimentation results suggests that the assembly pathway does
not here sensitively depend on the nature of the out-of-equilibrium dynamics.


title:
Knowledge-Based Biomedical Word Sense Disambiguation with Neural Concept
  Embeddings

abstract:
  Biomedical word sense disambiguation (WSD) is an important intermediate task
in many natural language processing applications such as named entity
recognition, syntactic parsing, and relation extraction. In this paper, we
employ knowledge-based approaches that also exploit recent advances in neural
word/concept embeddings to improve over the state-of-the-art in biomedical WSD
using the MSH WSD dataset as the test set. Our methods involve weak supervision
- we do not use any hand-labeled examples for WSD to build our prediction
models; however, we employ an existing well known named entity recognition and
concept mapping program, MetaMap, to obtain our concept vectors. Over the MSH
WSD dataset, our linear time (in terms of numbers of senses and words in the
test instance) method achieves an accuracy of 92.24% which is an absolute 3%
improvement over the best known results obtained via unsupervised or
knowledge-based means. A more expensive approach that we developed relies on a
nearest neighbor framework and achieves an accuracy of 94.34%. Employing dense
vector representations learned from unlabeled free text has been shown to
benefit many language processing tasks recently and our efforts show that
biomedical WSD is no exception to this trend. For a complex and rapidly
evolving domain such as biomedicine, building labeled datasets for larger sets
of ambiguous terms may be impractical. Here, we show that weak supervision that
leverages recent advances in representation learning can rival supervised
approaches in biomedical WSD. However, external knowledge bases (here sense
inventories) play a key role in the improvements achieved.


title:
Portfolio Benchmarking under Drawdown Constraint and Stochastic Sharpe
  Ratio

abstract:
  We consider an investor who seeks to maximize her expected utility derived
from her terminal wealth relative to the maximum performance achieved over a
fixed time horizon, and under a portfolio drawdown constraint, in a market with
local stochastic volatility (LSV). In the absence of closed-form formulas for
the value function and optimal portfolio strategy, we obtain approximations for
these quantities through the use of a coefficient expansion technique and
nonlinear transformations. We utilize regularity properties of the risk
tolerance function to numerically compute the estimates for our approximations.
In order to achieve similar value functions, we illustrate that, compared to a
constant volatility model, the investor must deploy a quite different portfolio
strategy which depends on the current level of volatility in the stochastic
volatility model.


title: Measuring Fairness in Ranked Outputs

abstract:
  Ranking and scoring are ubiquitous. We consider the setting in which an
institution, called a ranker, evaluates a set of individuals based on
demographic, behavioral or other characteristics. The final output is a ranking
that represents the relative quality of the individuals. While automatic and
therefore seemingly objective, rankers can, and often do, discriminate against
individuals and systematically disadvantage members of protected groups. This
warrants a careful study of the fairness of a ranking scheme.
  In this paper we propose fairness measures for ranked outputs. We develop a
data generation procedure that allows us to systematically control the degree
of unfairness in the output, and study the behavior of our measures on these
datasets. We then apply our proposed measures to several real datasets, and
demonstrate cases of unfairness. Finally, we show preliminary results of
incorporating our ranked fairness measures into an optimization framework, and
show potential for improving fairness of ranked outputs while maintaining
accuracy.


title: A Morse deformation lemma at infinity

abstract:
  We prove a generalized version of the classic deformation lemma from Morse
Theory that considers functions going to $-\infty$ at a compact set, and
allowing the lower value of the deformation to be $-\infty$. The result is
valid for a class of functions satisfying a suitable growth condition.


title:
On the probability of positive-definiteness in the gGUE via
  semi-classical Laguerre polynomials

abstract:
  In this paper, we compute the probability that an $N \times N$ matrix from
the generalised Gaussian Unitary Ensemble (gGUE) is positive definite,
extending a previous result of Dean and Majumdar \cite{DM}. For this purpose,
we work out the large degree asymptotics of semi-classical Laguerre polynomials
and their recurrence coefficients, using the steepest descent analysis of the
corresponding Riemann--Hilbert problem.


title:
A broad perspective on multiple abundance populations in the globular
  cluster NGC 1851

abstract:
  We present an analysis of the multiple stellar populations of the globular
cluster NGC 1851. We used lower resolution spectra of giant stars to measure
CN, CH, and calcium H & K spectral indices, and determine elemental abundances
for carbon and nitrogen. The CN and CH indices were used to confirm that there
are four populations of stars in the cluster. The primordial population of
stars, with the lowest CN, was found to be generally chemically distinct in
elemental abundances from the second generation populations. As expected,
[N/Fe] increases with increasing CN strength, but the only other element that
correlated with CN was barium. The two largest populations of stars were found
to have the same rate of carbon astration as the stars ascend the giant branch.
We were also able to confirm that four previously identified extratidal stars
are chemically associated with the cluster. This work shows the benefit of
considering the chemistry of globular clusters with both high- and
low-resolution spectra.


title: Rotating Stars from Kepler Observed with Gaia DR1

abstract:
  Astrometric data from the recent Gaia Data Release 1 has been matched against
the sample of stars from Kepler with known rotation periods. A total of 1,299
bright rotating stars were recovered from the subset of Gaia sources with good
astrometric solutions, most with temperatures hotter than 5000 K. From these
sources, 894 were selected as lying near the main sequence using their absolute
G-band magnitudes. These main sequence stars show a bimodality in their
rotation period distribution, centered roughly around a 600 Myr
rotation-isochrone. This feature matches the bimodal period distribution found
in cooler stars with Kepler, but was previously undetected for solar-type stars
due to sample contamination by subgiants. A tenuous connection between the
rotation period and total proper motion is found, suggesting the period
bimodality is due to the age distribution of stars within ~300pc of the Sun,
rather than a phase of rapid angular momentum loss. This work emphasizes the
unique power for understanding stellar populations by combining temporal
monitoring from Kepler with astrometric data from Gaia.


title: Wulff shape for equilibrium phases

abstract:
  We use surface tension to distinguish between phases with isotropic internal
structure from phases which are microscopically anisotropic. There are many
interesting open problems, especially in two dimensions, and in phase
coexistence.

categories: math-ph cond-mat.stat-mech math.MP math.PR


title: Sobolev regularity for Convex Functionals on BD

abstract:
  We study Sobolev regularity results for minimisers of autonomous, convex
variational of linear growth which depend on the symmetric gradient rather than
the full gradient. This extends the results available in the literature for the
BV-setting to the case of functionals whose full gradients are a priori not
known to exist as matrix-valued Radon measures.


title:
Quantifying word salad: The structural randomness of verbal reports
  predicts negative symptoms and Schizophrenia diagnosis 6 months later

abstract:
  Background: The precise quantification of negative symptoms is necessary to
improve differential diagnosis and prognosis prediction in Schizophrenia. In
chronic psychotic patients, the representation of verbal reports as word graphs
provides automated sorting of schizophrenia, bipolar disorder and control
groups based on the degree of speech connectedness. Here we aim to use machine
learning to verify whether speech connectedness during first clinical contact
can predict negative symptoms and Schizophrenia diagnosis six months later.
Methods: PANSS scores and memory reports were collected from 21 patients
undergoing first clinical contact for recent-onset psychosis and followed for 6
months to establish DSM-IV diagnosis, and 21 healthy controls. Each report was
represented as a graph in which words corresponded to nodes, and node temporal
succession corresponded to edges. Three connectedness attributes were extracted
from each graph, z-scores to random graph distributions were measured,
correlated with the PANSS negative subscale, combined into a single
Fragmentation Index, and used for predictions. Findings: Random-like speech was
prevalent among Schizophrenia patients (64% x 5% in Control group, p=0.0002).
Connectedness explained 92% of the PANSS negative subscale variance (p=0.0001).
The Fragmentation Index classified low versus high scores of PANSS negative
subscale with 93% accuracy (AUC=1), predicted Schizophrenia diagnosis with 89%
accuracy (AUC=0.89), and was validated in an independent cohort of chronic
psychotic patients. Interpretation: The structural randomness of speech graph
connectedness is increased in Schizophrenia. It provides a quantitative
measurement of word salad as a Fragmentation Index that tightly correlates with
negative symptoms and predicts Schizophrenia diagnosis during first clinical
contact of recent-onset psychosis.


title:
Rapidly convergent quasi-periodic Green functions for scattering by
  arrays of cylinders---including Wood anomalies

abstract:
  This paper presents a full-spectrum Green function methodology (which is
valid, in particular, at and around Wood-anomaly frequencies) for evaluation of
scattering by periodic arrays of cylinders of arbitrary cross section-with
application to wire gratings, particle arrays and reflectarrays and, indeed,
general arrays of conducting or dielectric bounded obstacles under both TE and
TM polarized illumination. The proposed method, which, for definiteness is
demonstrated here for arrays of perfectly conducting particles under TE
polarization, is based on use of the shifted Green-function method introduced
in the recent contribution (Bruno and Delourme, Jour. Computat. Phys. pp.
262--290 (2014)). A certain infinite term arises at Wood anomalies for the
cylinder-array problems considered here that is not present in the previous
rough-surface case. As shown in this paper, these infinite terms can be treated
via an application of ideas related to the Woodbury-Sherman-Morrison formulae.
The resulting approach, which is applicable to general arrays of obstacles even
at and around Wood-anomaly frequencies, exhibits fast convergence and high
accuracies. For example, a few hundreds of milliseconds suffice for the
proposed approach to evaluate solutions throughout the resonance region
(wavelengths comparable to the period and cylinder sizes) with full
single-precision accuracy.

categories: math.NA math-ph math.MP physics.comp-ph physics.optics


title:
Stochastic First-Order Minimization Techniques Using Jensen Surrogates
  for X-Ray Transmission Tomography

abstract:
  Image reconstruction in X-ray transmission tomography has been an important
research field for decades. In light of data volume increasing faster than
processor speeds, one needs accelerated iterative algorithms to solve the
optimization problem in the X-ray CT application. Incremental methods, in which
a subset of data is being used at each iteration to accelerate the
computations, have been getting more popular lately in the machine learning and
mathematical optimization fields. The most popular member of this family of
algorithms in the X-ray CT field is ordered-subsets. Even though it performs
well in earlier iterations, the lack of convergence in later iterations is a
known phenomenon. In this paper, we propose two incremental methods that use
Jensen surrogates for the X-ray CT application, one stochastic and one
ordered-subsets type. Using measured data, we show that the stochastic variant
we propose outperforms other algorithms, including the gradient descent
counterparts.


title:
Relativistic dipole interaction and the topological nature for induced
  HMW and AC phases

abstract:
  In this work we give, for the first time, the full relativistic Lagrangian
density describing the motion of induced electric dipoles in the electric
fields which induce the dipole, and the magnetic fields which generate the HMW
topological phase. We then use this relativistic Lagrangian density to derive
the complete set of conditions for producing topological phases with induced
dipoles. We also give the relativistic Lagrangian density describing the motion
of induced magnetic dipoles in the magnetic fields which induce the dipole, and
the electric fields which generate the AC topological phase, and derive the
conditions for this AC phase to be topological. These conditions have been
incompletely discussed in previous studies. We note that, in both the AC and
HMW cases, the topological phases are generated by the cross product of
electric and magnetic fields in the form $\bm{B} \times \bm{E}$ which
reinforces the dual nature of these two topological phases.


title:
TrustBase: An Architecture to Repair and Strengthen Certificate-based
  Authentication

abstract:
  We describe TrustBase, an architecture that provides certificate-based
authentication as an operating system service. TrustBase enforces best
practices for certificate validation for all applications and transparently
enables existing applications to be strengthened against failures of the CA
system. The TrustBase system allows simple deployment of authentication systems
that harden the CA system. This enables system administrators, for example, to
require certificate revocation checks on all TLS connections, or require
STARTTLS for email servers that support it. TrustBase is the first system that
is able to secure all TLS traffic, using an approach compatible with all
operating systems. We design and evaluate a prototype implementation of
TrustBase on Linux, evaluate its security, and demonstrate that it has
negligible overhead and universal compatibility with applications. To
demonstrate the utility of TrustBase, we have developed six authentication
services that strengthen certificate validation for all applications.


title:
EPIC 219388192 b - an inhabitant of the brown dwarf desert in the
  Ruprecht 147 open cluster

abstract:
  We report the discovery of EPIC 219388192 b, a transiting brown dwarf in a
5.3-day orbit around a member star of Ruprecht-147, the oldest nearby open
cluster association, which was photometrically monitored by K2 during its
Campaign 7. We combine the K2 time-series data with ground-based adaptive
optics imaging and high resolution spectroscopy to rule out false positive
scenarios and determine the main parameters of the system. EPIC 219388192 b has
a radius of $R_\mathrm{b}$=$0.937\pm0.042$~$\mathrm{R_{Jup}}$ and mass of
$M_\mathrm{b}$=$36.50\pm0.09$~$\mathrm{M_{Jup}}$, yielding a mean density of
$59.0\pm8.1$~$\mathrm{g\,cm^{-3}}$. The host star is nearly a Solar twin with
mass $M_\star$=$0.99\pm0.05$~$\mathrm{M_{\odot}}$, radius
$R_\star$=$1.01\pm0.04$~$\mathrm{R_{\odot}}$, effective temperature
$\mathrm{T_{eff}}$=$5850\pm85$~K and iron abundance [Fe/H]=$0.03\pm0.08$~dex.
Its age, spectroscopic distance, and reddening are consistent with those of
Ruprecht-147, corroborating its cluster membership. EPIC 219388192 b is the
first brown dwarf with precise determinations of mass, radius and age, and
serves as benchmark for evolutionary models in the sub-stellar regime.


title: Curve test for enhanced ind-sheaves and holonomic D-modules

abstract:
  Recently, the Riemann-Hilbert correspondence was generalized in the context
of general holonomic D-modules by A. D'Agnolo and M. Kashiwara. Namely, they
proved that their enhanced de Rham functor gives a fully faithfully embedding
of the derived category of cohomologically holonomic complexes of D-modules
into the derived category of complexes of real constructible enhanced
ind-sheaves.
  In this paper, we study a condition when a complex of real constructible
enhanced ind-sheaves $K$ is induced by a cohomologically holonomic complex of
D-modules. We characterize such $K$ in terms of the restriction of $K$ to
holomorphic curves.