title:
On the Partial-Wave Analysis of Mesonic Resonances Decaying to
  Multiparticle Final States Produced by Polarized Photons

abstract:
  Meson spectroscopy is going through a revival with the advent of high
statistics experiments and new advances in the theoretical predictions. The
Constituent Quark Model (CQM) is finally being expanded considering more basic
principles of field theory and using discrete calculations of Quantum
Chromodynamics (lattice QCD). These new calculations are approaching predictive
power for the spectrum of hadronic resonances and decay modes. It will be the
task of the new experiments to extract the meson spectrum from the data and
compare with those predictions. The goal of this report is to describe one
particular technique for extracting resonance information from multiparticle
final states. The technique described here, partial wave analysis based on the
helicity formalism, has been used at Brookhaven National Laboratory (BNL) using
pion beams, and Jefferson Laboratory (JLab) using photon beams. In particular
this report broadens this technique to include production experiments using
linearly polarized real photons or quasi-real photons. This article is of a
didactical nature. We describe the process of analysis, detailing assumptions
and formalisms, and is directed towards people interested in starting partial
wave analysis.


title: Extracting black-hole rotational energy: The generalized Penrose process

abstract:
  In the case involving particles the necessary and sufficient condition for
the Penrose process to extract energy from a rotating black hole is absorption
of particles with negative energies and angular momenta. No torque at the
black-hole horizon occurs. In this article we consider the case of arbitrary
fields or matter described by an unspecified, general energy-momentum tensor
$T_{\mu \nu}$ and show that the necessary and sufficient condition for
extraction of a black hole's rotational energy is analogous to that in the
mechanical Penrose process: absorption of negative energy and negative angular
momentum. We also show that a necessary condition for the Penrose process to
occur is for the Noether current (the conserved energy-momentum density vector)
to be spacelike or past directed (timelike or null) on some part of the
horizon. In the particle case, our general criterion for the occurrence of a
Penrose process reproduces the standard result. In the case of relativistic
jet-producing "magnetically arrested disks" we show that the negative energy
and angular-momentum absorption condition is obeyed when the Blandford-Znajek
mechanism is at work, and hence the high energy extraction efficiency up to
$\sim 300\%$ found in recent numerical simulations of such accretion flows
results from tapping the black hole's rotational energy through the Penrose
process. We show how black-hole rotational energy extraction works in this case
by describing the Penrose process in terms of the Noether current.


title:
On-demand dark soliton train manipulation in a spinor polariton
  condensate

abstract:
  We theoretically demonstrate the generation of dark solitons trains in a
one-dimensional exciton- polariton condensate within an experimentally trivial
scheme. In particular we show that the fre- quency of the train can be finely
tuned either electrically of fully optically to provide a stable and efficient
output signal modulation. Taking the polarization degree of freedom into
account we elucidate the possibility to additionally form on-demand
half-solitons trains.


title: The Inferred Cardiogenic Gene Regulatory Network in the Mammalian Heart

abstract:
  Cardiac development is complex, multiscale process encompassing cell fate
adoption, differentiation and morphogenesis. To elucidate pathways underlying
this process, a recently developed algorithm to reverse engineer gene
regulatory networks was applied to time-course microarray data obtained from
the developing mouse heart. The algorithm generates many different putative
network topologies that are capable of explaining the experimental data via
model simulation. To cull specious network interactions, thousands of
topologies are merged and filtered to generate a scale-free, hierarchical
network. The network is validated with known gene interactions and used to
identify regulatory pathways critical to the developing mammalian heart. The
predicted gene interactions are prioritized using semantic similarity and gene
profile uniqueness metrics. Using these metrics, the network is expanded to
include all known mouse genes to form the most likely cardiogenic gene
regulatory network. The method outlined herein provides an informative approach
to network inference and leads to clear testable hypotheses related to gene
regulation.


title:
Positions of Pluto extracted from digitized Pulkovo photographic plates
  taken in 1930 - 1960

abstract:
  We present the results of determination of Pluto's positions derived from
photographic plates taken in 1930 - 1960. Observations were made with Normal
Astrograph at Pulkovo Observatory. Digitization of these plates was performed
with high precision scanner at Royal Observatory of Belgium (ROB Digitizer).
Mean values of standard errors of plate positions (x,y) lie between 12 and 18
mas. The UCAC4 catalogue was used as an astrometric calibrator. Standard errors
of equatorial coordinates obtained are within 85 to 100 mas. Final table
contains 63 positions of Pluto referred to the HCRF/UCAC4 frame.


title:
Modelling binary rotating stars by new population synthesis code
  BONNFIRES

abstract:
  BONNFIRES, a new generation of population synthesis code, can calculate
nuclear reaction, various mixing processes and binary interaction in a timely
fashion. We use this new population synthesis code to study the interplay
between binary mass transfer and rotation. We aim to compare theoretical models
with observations, in particular the surface nitrogen abundance and rotational
velocity. Preliminary results show binary interactions may explain the
formation of nitrogen-rich slow rotators and nitrogen-poor fast rotators, but
more work needs to be done to estimate whether the observed frequencies of
those stars can be matched.


title:
Analysis of interior penalty discontinuous Galerkin methods for the
  Allen-Cahn equation and the mean curvature flow

abstract:
  This paper develops and analyzes two fully discrete interior penalty
discontinuous Galerkin (IP-DG) methods for the Allen-Cahn equation, which is a
nonlinear singular perturbation of the heat equation and originally arises from
phase transition of binary alloys in materials science, and its sharp interface
limit (the mean curvature flow) as the perturbation parameter tends to zero.
Both fully implicit and energy-splitting time-stepping schemes are proposed.
The primary goal of the paper is to derive sharp error bounds which depend on
the reciprocal of the perturbation parameter $\epsilon$ (also called
"interaction length") only in some lower polynomial order, instead of
exponential order, for the proposed IP-DG methods. The derivation is based on a
refinement of the nonstandard error analysis technique first introduced in
[12]. The centerpiece of this new technique is to establish a spectrum estimate
result in totally discontinuous DG finite element spaces with a help of a
similar spectrum estimate result in the conforming finite element spaces which
was established in [12]. As a nontrivial application of the sharp error
estimates, they are used to establish convergence and the rates of convergence
of the zero level sets of the fully discrete IP-DG solutions to the classical
and generalized mean curvature flow. Numerical experiment results are also
presented to gauge the theoretical results and the performance of the proposed
fully discrete IP-DG methods.


title:
Quantifying age- and gender-related diabetes comorbidity risks using
  nation-wide big claims data

abstract:
  Currently emerging "big data" techniques are reshaping medical science into a
data science. Medical claims data allow assessing an entire nation's health
state in a quantitative way, in particular with regard to the occurrences and
consequences of chronic and pandemic diseases like diabetes.
  We develop a quantitative, statistical approach to test for associations
between the incidence of type 1 or type 2 diabetes and any possible other
disease as provided by the ICD10 diagnosis codes using a complete set of
Austrian inpatient data. With a new co-occurrence analysis the relative risks
for each possible comorbidity are studied as a function of patient age and
gender, a temporal analysis investigates whether the onset of diabetes
typically precedes or follows the onset of the other disease. The samples is
always of maximal size, i.e. contains all patients with that comorbidity within
the country. The present study is an equivalent of almost 40,000 studies, all
with maximum patient number available. Out of more than thousand possible
associations, 123 comorbid diseases for type 1 or type 2 diabetes are
identified at high significance levels.
  Well known diabetic comorbidities are recovered, such as retinopathies,
hypertension, chronic kidney diseases, etc. This validates the method.
Additionally, a number of comorbidities are identified which have only been
recognized to a lesser extent, for example epilepsy, sepsis, or mental
disorders. The temporal evolution, age, and gender-dependence of these
comorbidities are discussed. The new statistical-network methodology developed
here can be readily applied to other chronic diseases.


title:
Fluctuation of similarity (FLUS) to detect transitions between distinct
  dynamical regimes in short time series

abstract:
  Recently a method which employs computing of fluctuations in a measure of
nonlinear similarity based on local recurrence properties in a univariate time
series, was introduced to identify distinct dynamical regimes and transitions
between them in a short time series [1]. Here we present the details of the
analytical relationships between the newly introduced measure and the well
known concepts of attractor dimensions and Lyapunov exponents. We show that the
new measure has linear dependence on the effective dimension of the attractor
and it measures the variations in the sum of the Lyapunov spectrum. To
illustrate the practical usefulness of the method, we employ it to identify
various types of dynamical transitions in different nonlinear models. Also, we
present testbed examples for the new method's robustness against the presence
of noise and missing values in the time series. Furthermore, we use this method
to analyze time series from the field of social dynamics, where we present an
analysis of the US crime record's time series from the year 1975 to 1993. Using
this method, we have found that dynamical complexity in robberies was
influenced by the unemployment rate till late 1980's. We have also observed a
dynamical transition in homicide and robbery rates in the late 1980's and early
1990's, leading to increase in the dynamical complexity of these rates.


title:
Radiative pi^pm gamma transitions of excited light-quark mesons in the
  covariant oscillator quark model

abstract:
  The COMPASS collaboration, as a part of their hadron spectroscopy program, is
going to measure the radiative decay widths of light-quark mesons via the
Primakoff reactions. In this letter we study the photon couplings of
light-quark q qbar states in the covariant oscillator quark model and evaluate
the transition rates for {rho(770), b_1(1235), a_1(1260), a_2(1320),
pi_2(1670), rho_3(1690), rho(1700)}^pm to pi^pm gamma, which are expected to be
measured by the COMPASS. Such photon couplings could be useful not only for
understanding the internal structures of observed light-quark mesons and their
quark-model classification but also for the ongoing experimental studies by
COMPASS.


title:
Giant Collective Spin-Orbit Field in a Quantum Well: Fine Structure of
  Spin Plasmons

abstract:
  We employ inelastic light scattering with magnetic fields to study
intersubband spin plasmons in a quantum well. We demonstrate the existence of a
giant collective spin-orbit (SO) field that splits the spin-plasmon spectrum
into a triplet. The effect is remarkable as each individual electron would be
expected to precess in its own momentum-dependent SO field, leading to
D'yakonov-Perel' dephasing. Instead, many-body effects lead to a striking
organization of the SO fields at the collective level. The macroscopic spin
moment is quantized by a uniform collective SO field, five times higher than
the individual SO field. We provide a momentum-space cartography of this field.


title: Notes on Enhancement of Flavor Symmetry and 5d Superconformal Index

abstract:
  The UV fixed point theory of SU(2) gauge theory with N_f = 0,1,...,7 flavors
is believed to have the enlarged E_{N_f +1} flavor symmetry. Actually it is not
easy to check this conjecture because the UV theory is strongly-coupled,
however, computation of certain SUSY protected quantities provides strong
evidence for the enhancement of flavor symmetry. We study the superconformal
index for SU(2) gauge theory with N_f = 0, 1 flavors in details, and we give a
support for the enhancement by studying combinatorial structure of the
superconformal indexes of these theories. We also give a nontrivial evidence
that the local F_2 geometry leads to the E_1 superconformal field theory.


title: The Impact of Organic Friction Modifiers on Engine Oil Tribofilms

abstract:
  Organic friction modifiers (OFMs) are important additives in the lubrication
of machines and especially of car engines where performance improvements are
constantly sought-after. Together with zinc dialkyldithiophosphates (ZDDPs)
antiwear additives, OFMs have a predominant impact on the tribological
behaviour of the lubricant. In the current study, the influence of OFMs on the
generation, tribological properties and chemistry of ZDDP tribofilms has been
investigated by combining tribological experiments (MTM) with in-situ film
thickness measurements through optical interference imaging (SLIM), Alicona
profilometry and X-ray photoelectron spectroscopy. OFMs and antiwear additives
have been found to competitively react/adsorb on the rubbing ferrous substrates
in a tribological contact. The formation and removal (through wear) of
tribofilms are dynamic processes which result from the simultaneous interaction
of these two additives with the surface of the wear track. By carefully
selecting the chemistry of OFMs, the formulator can achieve lubricants that
generate ZDDP antiwear films of optimum thickness, morphology and friction
according to the application-specific requirements.


title: A Criterion for the Bipartite Separability of Bell Diagonal States

abstract:
  A decomposition form is introduced in this report to establish a criterion
for the bi-partite separability of Bell diagonal states. A such criterion takes
a quadratic form of the coefficients of a given Bell diagonal states and can be
derived via a simple algorithmic calculation of its invariants. In addition,
the criterion can be extended to a quantum system of higher dimension.


title: A Decomposition Form of the Werner State

abstract:
  In this report, a scheme different from the PT and Wootters concurrence is
developed to acquire a criterion to investigate the bipartite separability of
the Werner state.


title:
Existence of a persistent hub in the convex preferential attachment
  model

abstract:
  A vertex of a randomly growing graph is called a persistent hub if at all but
finitely many moments of time it has the maximal degree in the graph. We
establish the existence of a persistent hub in the Barab\'asi--Albert random
graph model with probability one. We also extend this result to the class of
convex preferential attachment graphs, where a vertex of degree $k$ gets a new
edge with probability proportional to some convex function of $k$.


title: Algebraic Quantum Error-Correction Codes

abstract:
  Based on the group structure of a unitary Lie algebra, a scheme is provided
to systematically and exhaustively generate quantum error correction codes,
including the additive and nonadditive codes. The syndromes in the process of
error-correction distinguished by different orthogonal vector subspaces, the
coset subspaces. Moreover, the generated codes can be classified into four
types with respect to the spinors in the unitary Lie algebra and a chosen
initial quantum state.


title:
Precise determination of the spectroscopic g-factor using broadband
  ferromagnetic resonance spectroscopy

abstract:
  We demonstrate that the spectroscopic g-factor can be determined with high
precision and accuracy by broadband ferromagnetic resonance measurements and
applying an asymptotic analysis to the data. Spectroscopic data used to
determine the g-factor is always obtained over a finite range of frequencies,
which can result in significant errors in the fitted values of the
spectroscopic g-factor. We show that by applying an asymptotic analysis to
broadband datasets, precise values of the intrinsic g-factor can be determined
with errors well below 1 %, even when the exact form of the Kittel equation
(which describes the relationship between the frequency and resonance field) is
unknown. We demonstrate this methodology with measured data obtained for
sputtered Ni80Fe20 ("Permalloy") thin films of varied thicknesses, where we
determine the bulk g-factor value to be 2.109 +/- 0.003. Such an approach is
further validated by application to simulated data that includes both noise and
an anisotropy that is not included in the Kittel equation that was used in the
analysis. Finally, we show a correlation of thickness and interface structure
to the magnitude of the asymptotic behavior, which provide insight into
additional mechanisms that may induce deviations from the Kittel equation.


title:
Coupling between bulk- and surface chemistry in suspensions of charged
  colloids

abstract:
  The ionic composition and pair correlations in fluid phases of realistically
salt-free charged colloidal sphere suspensions are calculated in the primitive
model. We obtain the number densities of all ionic species in suspension,
including low-molecular weight microions, and colloidal macroions with acidic
surface groups, from a self-consistent solution of a coupled physicochemical
set of nonlinear algebraic equations and non-mean-field liquid integral
equations. Here, we study suspensions of colloidal spheres with sulfonate or
silanol surface groups, suspended in demineralized water that is saturated with
carbon dioxide under standard atmosphere. The only input required for our
theoretical scheme are the acidic dissociation constants pKa, and effective
sphere diameters of all involved ions. Our method allows for an ab initio
calculation of colloidal bare and effective charges, at high numerical
efficiency.


title:
The Impact of Magnification and Size Bias on Weak Lensing Power Spectrum
  and Peak Statistics

abstract:
  The weak lensing power spectrum is a powerful tool to probe cosmological
parameters. Additionally, lensing peak counts contain cosmological information
beyond the power spectrum. Both of these statistics can be affected by the
preferential selection of source galaxies in patches of the sky with high
magnification, as well as by the dilution in the source galaxy surface density
in such regions. If not accounted for, these biases introduce systematic errors
for cosmological measurements. Here we quantify these systematic errors, using
convergence maps from a suite of ray-tracing N-body simulations. At the cut-off
magnitude m of on-going and planned major weak lensing surveys, the logarithmic
slope of the cumulative number counts s = dlog[n(>m)]/dlog(m) is in the range
0.1 < s < 0.5. At s = 0.2, expected in the I band for LSST, the inferred values
of Omega_m, w and sigma_8 are biased by many sigma (where sigma denotes the
marginalized error) and therefore the biases will need to be carefully modeled.
We also find that the parameters are biased differently in the (Omega_m, w,
sigma_8) parameter space when the power spectrum and when the peak counts are
used. In particular, w derived from the power spectrum is less affected than w
derived from peak counts, while the opposite is true for the best-constrained
combination of [sigma_8 Omega_m^gamma] (with gamma=0.62 from the power spectrum
and gamma = 0.48 from peak counts). This suggests that the combination of the
power spectrum and peak counts can help mitigate the impact of magnification
and size biases.


title:
Obtaining localization properties efficiently using the Kubo-Greenwood
  formalism

abstract:
  We establish, through numerical calculations and comparisons with a recursive
Green's function based implementation of the Landauer-B\"uttiker formalism, an
efficient method for studying Anderson localization in quasi-one-dimensional
and two-dimensional systems using the Kubo-Greenwood formalism. Although the
recursive Green's function method can be used to obtain the localization length
of a mesoscopic conductor, it is numerically very expensive for systems that
contain a large number of atoms transverse to the transport direction. On the
other hand, linear-scaling has been achieved with the Kubo-Greenwood method,
enabling the study of effectively two-dimensional systems. While the
propagating length of the charge carriers will eventually saturate to a finite
value in the localized regime, the conductances given by the Kubo-Greenwood
method and the recursive Green's function method agree before the saturation.
The converged value of the propagating length is found to be directly
proportional to the localization length obtained from the exponential decay of
the conductance.


title:
Nuclear three-body problem in the complex energy plane:
  Complex-Scaling-Slater method

abstract:
  The physics of open quantum systems is an interdisciplinary area of research.
The nuclear "openness" manifests itself through the presence of the many-body
continuum representing various decay, scattering, and reaction channels. As the
radioactive nuclear beam experimentation extends the known nuclear landscape
towards the particle drip lines, the coupling to the continuum space becomes
exceedingly more important. Of particular interest are weakly bound and unbound
nuclear states appearing around particle thresholds. Theories of such nuclei
must take into account their open quantum nature. To describe open quantum
systems, we introduce a Complex Scaling (CS) approach in the Slater basis. We
benchmark it with the complex-energy Gamow Shell Model (GSM) by studying
energies and wave functions of the bound and unbound states of the two-neutron
halo nucleus 6He viewed as an $\alpha$+ n + n cluster system. In the CS
approach, we use the Slater basis, which exhibits the correct asymptotic
behavior at large distances. To extract particle densities from the
back-rotated CS solutions, we apply the Tikhonov regularization procedure,
which minimizes the ultraviolet numerical noise. While standard applications of
the inverse complex transformation to the complex-rotated solution provide
unstable results, the stabilization method fully reproduces the GSM benchmark.
We also propose a method to determine the smoothing parameter of the Tikhonov
regularization. The combined suite of CS-Slater and GSM techniques has many
attractive features when applied to nuclear problems involving weakly-bound and
unbound states. While both methods can describe energies, total widths, and
wave functions of nuclear states, the CS-Slater method, if it can be applied,
can provide an additional information about partial energy widths associated
with individual thresholds.


title:
Principle of Maximum Entanglement Entropy and Local Physics of
  Correlated many-body Electron-Systems

abstract:
  We argue that, because of the quantum-entanglement, the local physics of the
strongly-correlated materials at zero temperature is described in very good
approximation by a simple generalized Gibbs distribution, which depends on a
relatively small number local quantum thermodynamical potentials. We
demonstrate that our statement is exact in certain limits, and we perform
numerical calculations of the iron compounds FeSe and FeTe and of the elemental
cerium by employing the Gutzwiller Approximation (GA) that strongly support our
theory in general.


title:
Electron Pulse Compression with a Practical Reflectron Design for
  Ultrafast Electron Diffraction

abstract:
  Ultrafast electron diffraction (UED) is a powerful method for studying
time-resolved structural changes. Currently, space charge induced temporal
broadening prevents obtaining high brightness electron pulses with sub-100 fs
durations limiting the range of phenomena that can be studied with this
technique. We review the state of the the art of UED in this respect and
propose a practical design for reflectron based pulse compression which
utilizes only electro-static optics and has a tunable temporal focal point. Our
simulation shows that this scheme is capable of compressing an electron pulse
containing 100,000 electrons with 60:1 temporal compression ratio.


title: Protrusion fluctuations direct cell motion

abstract:
  Many physiological phenomena involve directional cell migration. It is
usually attributed to chemical gradients in vivo. Recently, other cues have
been shown to guide cells in vitro, including stiffness/adhesion gradients or
micro-patterned adhesive motifs. However, the cellular mechanism leading to
these biased migrations remains unknown, and, often, even the direction of
motion is unpredictable. In this study, we show the key role of fluctuating
protrusions on ratchet-like structures in driving NIH3T3 cell migration. We
identified the concept of efficient protrusion and an associated direction
index. Our analysis of the protrusion statistics facilitated the quantitative
prediction of cell trajectories in all investigated conditions. We varied the
external cues by changing the adhesive patterns. We also modified the internal
cues using drug treatments, which modified the protrusion activity.
Stochasticity affects the short- and long-term steps. We developed a
theoretical model showing that an asymmetry in the protrusion fluctuations is
sufficient for predicting all measures associated with the long-term motion,
which can be described as a biased persistent random walk.


title: Quantum Shuffles and Quantum Supergroups of Basic Type

abstract:
  We initiate the study of several distinguished bases for the positive half of
a quantum supergroup $U_q$ associated to a general super Cartan datum
$(\mathrm{I}, (\cdot,\cdot))$ of basic type inside a quantum shuffle
superalgebra. The combinatorics of words for an arbitrary total ordering on
$\mathrm{I}$ is developed in connection with the root system associated to
$\mathrm{I}$. The monomial, Lyndon, and PBW bases of $U_q$ are constructed, and
moreover, a direct proof of the orthogonality of the PBW basis is provided
within the framework of quantum shuffles. Consequently, the canonical basis is
constructed for $U_q$ associated to the standard super Cartan datum of type
$\mathfrak{gl}(n|1)$, $\mathfrak{osp}(1|2n)$, or $\mathfrak{osp}(2|2n)$ or an
arbitrary non-super Cartan datum. In the non-super case, this refines Leclerc's
work and provides a new self-contained construction of canonical bases. The
canonical bases of $U_q$, of its polynomial modules, as well as of Kac modules
in the case of quantum $\mathfrak{gl}(2|1)$ are explicitly worked out.


title: Phase noise of oscillators with unsaturated amplifiers

abstract:
  We study the role of amplifier saturation in eliminating feedback noise in
self-sustained oscillators. We extend previous works that use a saturated
amplifier to quench fluctuations in the feedback magnitude, while
simultaneously tuning the oscillator to an operational point at which the
resonator nonlinearity cancels fluctuations in the feedback phase. We consider
a generalized model which features an amplitude-dependent amplifier gain
function. This allows us to determine the total oscillator phase noise in
realistic configurations due to noise in both quadratures of the feedback, and
to show that it is not necessary to drive the resonator to large oscillation
amplitudes in order to eliminate noise in the phase of the feedback.


title: Coding theorems for compound problems via quantum R\'enyi divergences

abstract:
  Recently, a new notion of quantum R\'enyi divergences has been introduced by
M\"uller-Lennert, Dupuis, Szehr, Fehr and Tomamichel, J.Math.Phys. 54:122203,
(2013), and Wilde, Winter, Yang, Commun.Math.Phys. 331:593--622, (2014), that
has found a number of applications in strong converse theorems. Here we show
that these new R\'enyi divergences are also useful tools to obtain coding
theorems in the direct domain of various problems. We demonstrate this by
giving new and considerably simplified proofs for the achievability parts of
Stein's lemma with composite null hypothesis, universal state compression, and
the classical capacity of compound classical-quantum channels, based on
single-shot error bounds already available in the literature, and simple
properties of the quantum R\'enyi divergences. The novelty of our proofs is
that the composite/compound coding theorems can be almost directly obtained
from the single-shot error bounds, with essentially the same effort as for the
case of simple null-hypothesis/single source/single channel.


title: KCH representations, augmentations, and $A$-polynomials

abstract:
  We describe a correspondence between augmentations and certain
representations of the knot group. The correspondence makes the 2-variable
augmentation polynomial into a generalization of the classical $A$-polynomial.
It also associates to an augmentation a rank, which is bounded by the bridge
number and shares its behavior under connect sums. We also study augmentations
with rank equal to the braid index.


title:
Knowledge-fused differential dependency network models for detecting
  significant rewiring in biological networks

abstract:
  Modeling biological networks serves as both a major goal and an effective
tool of systems biology in studying mechanisms that orchestrate the activities
of gene products in cells. Biological networks are context specific and dynamic
in nature. To systematically characterize the selectively activated regulatory
components and mechanisms, the modeling tools must be able to effectively
distinguish significant rewiring from random background fluctuations. We
formulated the inference of differential dependency networks that incorporates
both conditional data and prior knowledge as a convex optimization problem, and
developed an efficient learning algorithm to jointly infer the conserved
biological network and the significant rewiring across different conditions. We
used a novel sampling scheme to estimate the expected error rate due to random
knowledge and based on which, developed a strategy that fully exploits the
benefit of this data-knowledge integrated approach. We demonstrated and
validated the principle and performance of our method using synthetic datasets.
We then applied our method to yeast cell line and breast cancer microarray data
and obtained biologically plausible results.


title: A diabatic representation of the two lowest electronic states of Li3

abstract:
  Using the Multi-Reference Configuration Interaction method, the adiabatic
potential energy surfaces of Li3 are computed. The two lowest electronic states
are bound and exhibit a conical intersection. By fitting the calculated
potential energy surfaces to the cubic Exe Jahn-Teller model we extract the
effective Jahn-Teller parameters corresponding to Li3. These are used to set up
the transformation matrix which transforms from the adiabatic to a diabatic
representation. This diabatization method gives a Hamiltonian for Li3 which is
free from singular adiabatic couplings and should be accurate for large
internuclear distances, and it thereby allows for bound dynamics in the
vicinity of the conical intersection to be explored.


title:
Successive Nonnegative Projection Algorithm for Robust Nonnegative Blind
  Source Separation

abstract:
  In this paper, we propose a new fast and robust recursive algorithm for
near-separable nonnegative matrix factorization, a particular nonnegative blind
source separation problem. This algorithm, which we refer to as the successive
nonnegative projection algorithm (SNPA), is closely related to the popular
successive projection algorithm (SPA), but takes advantage of the nonnegativity
constraint in the decomposition. We prove that SNPA is more robust than SPA and
can be applied to a broader class of nonnegative matrices. This is illustrated
on some synthetic data sets, and on a real-world hyperspectral image.


title: Exact model structures and recollements

abstract:
  We show how to obtain recollements of triangulated categories using the
theory of exact model structures. After noting how the theory relates to
well-known notions in the simplest case of Frobenius categories, we apply these
ideas to recollements of homotopy categories of chain complexes. In short, we
give model categorical explanations for the classical Verdier localization
recollement as well as several recollement situations due to Neeman and Murfet.


title: Derivatives of the tree function

abstract:
  We study some sequences of polynomials that appear when we consider the
successive derivatives of the tree function (or Lambert's W function). We show
in particular that they are related with a generalization of Cayley trees,
called Greg trees. Besides the combinatorial result in itself, it is
interesting to see how this is related with previous work: similar problems
were considered first by Ramanujan, and more recently in the theory of
completely monotonic functions and its link with probability. Also of great
interest is the fact that these Greg trees were introduced in a problem of
textual criticism, as a kind a genealogical trees, where they had a priori no
mathematical meaning.


title:
Matchmaker, Matchmaker, Make Me a Match: Migration of Populations via
  Marriages in the Past

abstract:
  The study of human mobility is both of fundamental importance and of great
potential value. For example, it can be leveraged to facilitate efficient city
planning and improve prevention strategies when faced with epidemics. The
newfound wealth of rich sources of data---including banknote flows, mobile
phone records, and transportation data---has led to an explosion of attempts to
characterize modern human mobility. Unfortunately, the dearth of comparable
historical data makes it much more difficult to study human mobility patterns
from the past. In this paper, we present an analysis of long-term human
migration, which is important for processes such as urbanization and the spread
of ideas. We demonstrate that the data record from Korean family books (called
"jokbo") can be used to estimate migration patterns via marriages from the past
750 years. We apply two generative models of long-term human mobility to
quantify the relevance of geographical information to human marriage records in
the data, and we find that the wide variety in the geographical distributions
of the clans poses interesting challenges for the direct application of these
models. Using the different geographical distributions of clans, we quantify
the "ergodicity" of clans in terms of how widely and uniformly they have spread
across Korea, and we compare these results to those obtained using surname data
from the Czech Republic. To examine population flow in more detail, we also
construct and examine a population-flow network between regions. Based on the
correlation between ergodicity and migration in Korea, we identify two
different types of migration patterns: diffusive and convective. We expect the
analysis of diffusive versus convective effects in population flows to be
widely applicable to the study of mobility and migration patterns across
different cultures.

categories: physics.soc-ph cond-mat.dis-nn cs.CE nlin.AO q-bio.PE


title: Digraphs and cycle polynomials for free-by-cyclic groups

abstract:
  Let $\phi \in \mbox{Out}(F_n)$ be a free group outer automorphism that can be
represented by an expanding, irreducible train-track map. The automorphism
$\phi$ determines a free-by-cyclic group $\Gamma=F_n \rtimes_\phi \mathbb Z,$
and a homomorphism $\alpha \in H^1(\Gamma; \mathbb Z)$. By work of Neumann,
Bieri-Neumann-Strebel and Dowdall-Kapovich-Leininger, $\alpha$ has an open cone
neighborhood $\mathcal A$ in $H^1(\Gamma;\mathbb R)$ whose integral points
correspond to other fibrations of $\Gamma$ whose associated outer automorphisms
are themselves representable by expanding irreducible train-track maps. In this
paper, we define an analog of McMullen's Teichm\"uller polynomial that computes
the dilatations of all outer automorphism in $\mathcal A$.


title:
Order of Magnitude Smaller Limit on the Electric Dipole Moment of the
  Electron

abstract:
  The Standard Model (SM) of particle physics fails to explain dark matter and
why matter survived annihilation with antimatter following the Big Bang.
Extensions to the SM, such as weak-scale Supersymmetry, may explain one or both
of these phenomena by positing the existence of new particles and interactions
that are asymmetric under time-reversal (T). These theories nearly always
predict a small, yet potentially measurable ($10^{-27}$-$10^{-30}$ $e$ cm)
electron electric dipole moment (EDM, $d_e$), which is an asymmetric charge
distribution along the spin ($\vec{S}$). The EDM is also asymmetric under T.
Using the polar molecule thorium monoxide (ThO), we measure $d_e = (-2.1 \pm
3.7_\mathrm{stat} \pm 2.5_\mathrm{syst})\times 10^{-29}$ $e$ cm. This
corresponds to an upper limit of $|d_e| < 8.7\times 10^{-29}$ $e$ cm with 90
percent confidence, an order of magnitude improvement in sensitivity compared
to the previous best limits. Our result constrains T-violating physics at the
TeV energy scale.


title:
Improving Photoacoustic-guided Focusing in Scattering Media by
  Spectrally Filtered Detection

abstract:
  We experimentally and numerically study the potential of
photoacoustic-guiding for light focusing through scattering samples via
wavefront-shaping and iterative optimization. We experimentally demonstrate
that the focusing efficiency on an extended absorber can be improved by
iterative optimization of the high frequency components of the broadband
photoacoustic signal detected with a spherically focused transducer. We
demonstrate more than 8-fold increase in the photoacoustic signal generated by
a 30 microns wire using a narrow frequency band around 60MHz. We numerically
confirm that such optimization leads to a smaller optical focus than using the
low frequency content of the photoacoustic feedback.


title: New Constructions of Codes for Asymmetric Channels via Concatenation

abstract:
  We present new constructions of codes for asymmetric channels for both binary
and nonbinary alphabets, based on methods of generalized code concatenation.
For the binary asymmetric channel, our methods construct nonlinear
single-error-correcting codes from ternary outer codes. We show that some of
the Varshamov-Tenengol'ts-Constantin-Rao codes, a class of binary nonlinear
codes for this channel, have a nice structure when viewed as ternary codes. In
many cases, our ternary construction yields even better codes. For the
nonbinary asymmetric channel, our methods construct linear codes for many
lengths and distances which are superior to the linear codes of the same length
capable of correcting the same number of symmetric errors.
  In the binary case, Varshamov has shown that almost all good linear codes for
the asymmetric channel are also good for the symmetric channel. Our results
indicate that Varshamov's argument does not extend to the nonbinary case, i.e.,
one can find better linear codes for asymmetric channels than for symmetric
ones.


title:
Virtual Corrections to the NLO Splitting Functions for Monte Carlo: the
  non-singlet case

abstract:
  Construction of a QCD cascade at the NLO level requires recalculation of the
splitting functions in a different manner [1]. We describe the calculation of
some of the virtual contributions to the non-singlet splitting function. In
order to be compatible with the earlier calculated real contributions [2], the
principal value prescription for regularizing the infrared singularities must
be used in a new way. We illustrate this new scheme on simple examples. For the
calculations we wrote a Mathematica package called Axiloop. We describe its
current status.


title: Remarks on Tao's algebraic regularity lemma

abstract:
  We give a stability theoretic proof of the algebraic regularity lemma of Tao,
making use of a lemma of Hrushovski. We also point out that the underlying
results hold at the level of measurable theories and structures in the sense of
Elwes, Macpherson and Steinhorn.


title:
Quantized Coordinate Rings of the Unipotent Radicals of the Standard
  Borel Subgroups in $SL_{n+1}$

abstract:
  We define two subalgebras which can be seen as the quantization of the
coordinate rings of the unipotent radical of the standard positive
(respectively negative) Borel subgroup of $SL_{n+1}$. We give a presentation
for these algebras and show they are isomorphic. Moreover, we show that these
algebras are the conivariants of a natural $O_q(T)$-coaction on $O_q(B^\pm)$.
Finally, using a dual pairing, we show that these algebras are isomorphic to
the quantum nilpotent Lie subalgebra of $U_q(\mathfrak{sl}_{n+1})$.


title:
Modeling spin magnetization transport in a spatially varying magnetic
  field

abstract:
  We present a framework for modeling the transport of any number of globally
conserved quantities in any spatial configuration and apply it to obtain a
model of magnetization transport for spin-systems that is valid in new regimes
(including high-polarization). The framework allows an entropy function to
define a model that explicitly respects the laws of thermodynamics. Three
facets of the model are explored. First, it is expressed as nonlinear partial
differential equations that are valid for the new regime of high dipole-energy
and polarization. Second, the nonlinear model is explored in the limit of low
dipole-energy (semi-linear), from which is derived a physical parameter
characterizing separative magnetization transport (SMT). It is shown that the
necessary and sufficient condition for SMT to occur is that the parameter is
spatially inhomogeneous. Third, the high spin-temperature (linear) limit is
shown to be equivalent to the model of nuclear spin transport of Genack and
Redfield. Differences among the three forms of the model are illustrated by
numerical solution with parameters corresponding to a magnetic resonance force
microscopy (MRFM) experiment. A family of analytic, steady-state solutions to
the nonlinear equation is derived and shown to be the spin-temperature analog
of the Langevin paramagnetic equation and Curie's law. Finally, we analyze the
separative quality of magnetization transport, and a steady-state solution for
the magnetization is shown to be compatible with Fenske's separative mass
transport equation.


title: Quasi-phasematched laser wakefield acceleration

abstract:
  The energy gain in laser wakefield acceleration (LWFA) is ultimately limited
by dephasing, occurring when accelerated electrons outrun the accelerating
phase of the wakefield. We apply quasi-phasematching, enabled by axially
modulated plasma channels, to overcome this limitation. By matching the
modulation period to the dephasing length, a relativistic electron can undergo
energy gain over several dephasing lengths. Theory and simulations are
presented showing that at a weakly relativistic laser intensity, ~10^17 W/cm2,
and millijoule level pulse energies, quasi-phasematched LWFA results in energy
gains of 50 MeV larger than standard LWFA.


title: Topics in the Value Distribution of Random Analytic Functions

abstract:
  This thesis is concerned with the behavior of random analytic functions. In
particular, we are interested in the value distribution of Taylor series with
independent random coefficients.
  We begin with a study of the properties of Fourier series with random signs.
The main result states that the logarithm of such series is integrable (to any
power). Using this result, we answer an old question of J.-P. Kahane,
concerning the range of random Taylor series in the unit disk. In addition, we
prove a law of large numbers for the number of zeros of entire functions given
by Taylor series with random signs.
  Then we examine some 'rare' events related to the zero set of Gaussian entire
functions (given by a Taylor series). In particular, we are interested in the
'hole' event, where the function has no zeros inside a large disk, centered at
the origin. We give precise logarithmic asymptotics for the probability of this
event, as the radius tends to infinite, depending on the variance of the
coefficients of the series.
  It should be mentioned that our results do not assume any 'regularity'
conditions.


title: Chiral non-Fermi Liquids

abstract:
  A non-Fermi liquid state without time-reversal and parity symmetries arises
when a chiral Fermi surface is coupled with a soft collective mode in two space
dimensions. The full Fermi surface is described by a direct sum of chiral patch
theories, which are decoupled from each other in the low energy limit. Each
patch includes low energy excitations near a set of points on the Fermi surface
with a common tangent vector. General patch theories are classified by the
local shape of the Fermi surface, the dispersion of the critical boson, and the
symmetry group, which form the data for distinct universality classes. We prove
that a large class of chiral non-Fermi liquid states exist as stable critical
states of matter. For this, we use a renormalization group scheme where low
energy excitations of the Fermi surface are interpreted as a collection of
(1+1)-dimensional chiral fermions with a continuous flavor labelling the
momentum along the Fermi surface. Due to chirality, the Wilsonian effective
action is strictly UV finite. This allows one to extract the exact scaling
exponents although the theories flow to strongly interacting field theories at
low energies. In general, the low energy effective theory of the full Fermi
surface includes patch theories of more than one universality classes. As a
result, physical responses include multiple universal components at low
temperatures. We also point out that, in quantum field theories with extended
Fermi surface, a non-commutative structure naturally emerges between a
coordinate and a momentum which are orthogonal to each other. We show that the
invalidity of patch description for Fermi liquid states is tied with the
presence of UV/IR mixing associated with the emergent non-commutativity. On the
other hand, UV/IR mixing is suppressed in non-Fermi liquid states due to UV
insensitivity, and the patch description is valid.


title: Stochastization of BKL dynamics and Anisotropic Sky Patterns

abstract:
  The dynamics of cosmological billiards in $4=3+1$ spacetime dimensions is
analyzed; the different statistical maps are characterized within the
stochastic limit, reached after a large number of iterations of the billiard
maps. New densities of invariant measures have been established, also for
billiard systems which contain symmetry walls, according to the content of Weyl
reflections in the maps, which account for the change of sign of the
non-oscillating scale factors in the solution to the Einstein field equations.
The statistical equivalence between the big billiard and the small billiard,
posed in [Phys. Rev. D83, 044038 (2011)], is here proven by means of these new
definitions of probabilities for the small billiard. Further new classes of BKL
probabilities have also been defined especially for the one-variable map and
for the two-variable map, for the early-time BKL dynamics, for a stochastizing
BKL dynamics and for a completely stochastized dynamics, both for the big
billiard and for the small billiard. The trajectories have been classified
according to these new probabilties, and different specifications of
probabilties comparing classes of initial conditions have been assigned for the
stochastization of the dynamics. As a result, is is possible to establish a
definition of BKL probabilities for the unquotiented dynamics of the big
billiard, where the different patterns of Weyl reflections are encoded. The
statistical description of BKL probabilities for the occurrence of a given
number of epochs in each era are therefore further characterized by the most
probable number of Weyl reflections contained in such eras, which is inferred
from the implications of the billiard maps on the UPHP. These new constructions
have been considered for the determination of the connection between the
observed values of anisotropy by a stochastic limit of the BKL dynamics.


title:
Confinement, quark mass functions, and spontaneous chiral symmetry
  breaking in Minkowski space

abstract:
  We formulate the covariant equations for quark-antiquark bound states in
Minkowski space in the framework of the Covariant Spectator Theory. The quark
propagators are dressed with the same kernel that describes the interaction
between different quarks. We show that these equations are charge-conjugation
invariant, and that in the chiral limit of vanishing bare quark mass, a
massless pseudoscalar bound state is produced in a Nambu-Jona-Lasinio (NJL)
mechanism, which is associated with the Goldstone boson of spontaneous chiral
symmetry breaking. In this introductory paper, we test the formalism by using a
simplified kernel consisting of a momentum-space delta-function with a vector
Lorentz structure, to which one adds a mixed scalar and vector confining
interaction. The scalar part of the confining interaction is not chirally
invariant by itself, but decouples from the equations in the chiral limit and
therefore allows the NJL mechanism to work. With this model we calculate the
quark mass function, and we compare our Minkowski-space results to lattice QCD
data obtained in Euclidean space. In a companion paper, we apply this formalism
to a calculation of the pion form factor.


title:
Enhanced Superconductivity on the Tetragonal Lattice in FeSe under
  Hydrostatic Pressure

abstract:
  Superconductivity under pressure in FeSe ($T_{\rm c}$$\sim$7.5 K) has been
investigated using single-crystal specimens through the measurements of DC
magnetization and electrical resistivity. A characteristic three-step increase
in $T_{\rm c}$ has been found under hydrostatic pressure up to $\sim$34 K above
7 GPa. The structural transition from a tetragonal phase to an orthorhombic
phase ($T_{\rm s}$$\sim$87 K) is found to disappear at $P$$\sim$2.3 GPa, above
which $T_{\rm c}$ increases rapidly, suggesting that the superconductivity is
enhanced by the tetragonal environment. Under non-hydrostatic pressure, the
increase in $T_{\rm c}$ is suppressed and the superconductive volume fraction
is considerably reduced above 2 GPa, probably owing to the breaking of the
tetragonal lattice symmetry by the uniaxial stress. The intimate correlation
between the enhanced (suppressed) superconductivity and the tetragonality
(orthorhombicity) in the phase diagram is a common feature of FeSe and other
iron-pnictide superconductors.


title:
Extragalactic Foreground Contamination in Temperature-based CMB Lens
  Reconstruction

abstract:
  We discuss the effect of unresolved point source contamination on estimates
of the CMB lensing potential, from components such as the thermal
Sunyaev-Zel'dovich effect, radio point sources, and the Cosmic Infrared
Background. We classify the possible trispectra associated with such source
populations, and construct estimators for the amplitude and scale-dependence of
several of the major trispectra. We show how to propagate analytical models for
these source trispectra to biases for lensing. We also construct a
"source-hardened" lensing estimator which experiences significantly smaller
biases when exposed to unresolved point sources than the standard quadratic
lensing estimator. We demonstrate these ideas in practice using the sky
simulations of Sehgal et. al., for cosmic-variance limited experiments designed
to mimic ACT, SPT, and Planck.


title:
Working with Kolya Uraltsev for twenty-five years about Fundamental
  Dynamics & Symmetries and for the future -- like CP Violation & EDMs

abstract:
  Working with Kolya Uraltsev was a real `marvel' for me about CP & T
violation, QCD & its impact on transitions in heavy flavor hadrons, EDMs. The
goal was -- and still is -- to define fundamental parameters dynamics, how to
measure them and compare SM forces with New Dynamics using the best theoretical
tools including our brains. The correlations of them with accurate data were
crucial for Kolya. Here is a review of CP asymmetries in $B$ & $D$ mesons and
$\tau$ decays, the impact of perturbative and non-perturbative QCD, about EDMs
till 2013 -- and for the future.


title:
A New Accretion Disk Around the Missing Link Binary System PSR
  J1023+0038

abstract:
  PSR J1023+0038 is an exceptional system for understanding how slowly rotating
neutron stars are spun up to millisecond rotational periods through accretion
from a companion star. Observed as a radio pulsar from 2007-2013, optical data
showed that the system had an accretion disk in 2000/2001. Starting at the end
of 2013 June, the radio pulsar has become undetectable, suggesting a return to
the previous accretion-disk state, where the system more closely resembles an
X-ray binary. In this Letter we report the first targeted X-ray observations
ever performed of the active phase and complement them with UV/Optical and
radio observations collected in 2013 October. We find strong evidence that
indeed an accretion disk has recently formed in the system and we report the
detection of fast X-ray changes spanning about two orders of magnitude in
luminosity. No radio pulsations are seen during low flux states in the X-ray
light-curve or at any other times.


title:
Complex Solitary Wave Dynamics, Pattern Formation, and Chaos in the
  Gain-Loss Nonlinear Schr\"odinger Equation

abstract:
  A numerical exploration of a gain-loss nonlinear Schr\"odinger equation was
carried out utilizing over 180000 core hours to conduct more than 10000 unique
simulations in an effort to characterize the model's six dimensional parameter
space. The study treated the problem in full generality, spanning a minimum of
eight orders of magnitude for each of three linear and nonlinear gain terms and
five orders of magnitude for higher order nonlinearities. The gain-loss
nonlinear Schr\"odinger equation is of interest as a model for spin wave
envelopes in magnetic thin film active feedback rings and analogous driven
damped nonlinear physical systems. Bright soliton trains were spontaneously
driven out of equilibrium and behaviors stable for tens of thousands of round
trip times were numerically identified. Nine distinct complex dynamical
behaviors with lifetimes on the order of ms were isolated as part of six
identified solution classes. Numerically located dynamical behaviors include:
(1) Low dimensional chaotic modulations of bright soliton trains; (2) spatially
symmetric/asymmetric interactions of solitary wave peaks; (3) dynamical pattern
formation and recurrence; (4) steady state solutions and (5) intermittency.
Simulations exhibiting chaotically modulating bright soliton trains were found
to qualitatively match previous experimental observations. Ten new dynamical
behaviors, eight demonstrating long lifetimes, are predicted to be observable
in future experiments.


title:
Validity of the two-band model of bilayer and trilayer graphene in a
  magnetic field

abstract:
  The eigenstates of an electron in the chiral two-dimensional electron gas
(C2DEG) formed in an AB-stacked bilayer or an ABC-stacked trilayer graphene is
a spinor with $4$ or $6$ components respectively. These components give the
amplitude of the wave function on the $4$ or $6$ carbon sites in the unit cell
of the lattice. In the tight-binding approximation, the eigenenergies are thus
found by diagonalizing a $4\times 4$ or a $6\times 6$ matrix. In the continuum
approximation where the electron wave vector $% k<<1/a_{0},$ with $a_{0}$ the
lattice constant of the graphene sheets, a common approximation is the two-band
model\cite{McCann2006} (2BM)\ where the eigenstates for the bilayer and
trilayer systems are described by a two-component spinor that gives the
amplitude of the wave function on the two sites with low-energy $\left\vert
E\right\vert <<\gamma_{1}$ where $% \gamma_{1}$ is the hopping energy between
sites that are directly above one another in adjacent layers. The 2BM has been
used extensively to study the phase diagram of the C2DEG in a magnetic field as
well as its transport and optical properties. In this paper, we use a numerical
approach to compute the eigenstates and Landau level energies of the full
tight-binding model in the continuum approximation and compare them with the
prediction of the 2BM when the magnetic field or an electrical bias between the
outermost layers is varied. Our numerical analysis shows that the 2BM is a good
approximation for bilayer graphene in a wide range of magnetic field and bias
but mostly for Landau level $M=0.$ The applicability of the 2BM in trilayer
graphene, even for level $M=0,$ is much more restricted. In this case, the 2BM\
fails to reproduce some of the level crossings that occur between the
sub-levels of $M=0.$


title: An Algorithm for Exact Super-resolution and Phase Retrieval

abstract:
  We explore a fundamental problem of super-resolving a signal of interest from
a few measurements of its low-pass magnitudes. We propose a 2-stage tractable
algorithm that, in the absence of noise, admits perfect super-resolution of an
$r$-sparse signal from $2r^2-2r+2$ low-pass magnitude measurements. The spike
locations of the signal can assume any value over a continuous disk, without
increasing the required sample size. The proposed algorithm first employs a
conventional super-resolution algorithm (e.g. the matrix pencil approach) to
recover unlabeled sets of signal correlation coefficients, and then applies a
simple sorting algorithm to disentangle and retrieve the true parameters in a
deterministic manner. Our approach can be adapted to multi-dimensional spike
models and random Fourier sampling by replacing its first step with other
harmonic retrieval algorithms.


title:
Three-loop Standard Model effective potential at leading order in strong
  and top Yukawa couplings

abstract:
  I find the three-loop contribution to the effective potential for the
Standard Model Higgs field, in the approximation that the strong and top Yukawa
couplings are large compared to all other couplings, using dimensional
regularization with modified minimal subtraction. Checks follow from gauge
invariance and renormalization group invariance. I also briefly comment on the
special problems posed by Goldstone boson contributions to the effective
potential, and on the numerical impact of the result on the relations between
the Higgs vacuum expectation value, mass, and self-interaction coupling.


title:
Discussion on climate oscillations: CMIP5 general circulation models
  versus a semi empirical harmonic model based on astronomical cycles

abstract:
  Power spectra of global surface temperature (GST) records reveal major
periodicities at about 9.1, 10-11, 19-22 and 59-62 years. The Coupled Model
Intercomparison Project 5 (CMIP5) general circulation models (GCMs), to be used
in the IPCC (2013), are analyzed and found not able to reconstruct this
variability. From 2000 to 2013.5 a GST plateau is observed while the GCMs
predicted a warming rate of about 2 K/century. In contrast, the hypothesis that
the climate is regulated by specific natural oscillations more accurately fits
the GST records at multiple time scales. The climate sensitivity to CO2
doubling should be reduced by half, e.g. from the IPCC-2007 2.0-4.5 K range to
1.0-2.3 K with 1.5 C median. Also modern paleoclimatic temperature
reconstructions yield the same conclusion. The observed natural oscillations
could be driven by astronomical forcings. Herein I propose a semi empirical
climate model made of six specific astronomical oscillations as constructors of
the natural climate variability spanning from the decadal to the millennial
scales plus a 50% attenuated radiative warming component deduced from the GCM
mean simulation as a measure of the anthropogenic and volcano contributions to
climatic changes. The semi empirical model reconstructs the 1850-2013 GST
patterns significantly better than any CMIP5 GCM simulation. The model projects
a possible 2000-2100 average warming ranging from about 0.3 C to 1.8 C that is
significantly below the original CMIP5 GCM ensemble mean range (1 K to 4 K).


title: The RoboPol Pipeline and Control System

abstract:
  We describe the data reduction pipeline and control system for the RoboPol
project. The RoboPol project is monitoring the optical $R$-band magnitude and
linear polarization of a large sample of active galactic nuclei that is
dominated by blazars. The pipeline calibrates and reduces each exposure frame,
producing a measurement of the magnitude and linear polarization of every
source in the $13'\times 13'$ field of view. The control system combines a
dynamic scheduler, real-time data reduction, and telescope automation to allow
high-efficiency unassisted observations.


title:
First Evaluation of the CPU, GPGPU and MIC Architectures for Real Time
  Particle Tracking based on Hough Transform at the LHC

abstract:
  Recent innovations focused around {\em parallel} processing, either through
systems containing multiple processors or processors containing multiple cores,
hold great promise for enhancing the performance of the trigger at the LHC and
extending its physics program. The flexibility of the CMS/ATLAS trigger system
allows for easy integration of computational accelerators, such as NVIDIA's
Tesla Graphics Processing Unit (GPU) or Intel's \xphi, in the High Level
Trigger. These accelerators have the potential to provide faster or more energy
efficient event selection, thus opening up possibilities for new complex
triggers that were not previously feasible. At the same time, it is crucial to
explore the performance limits achievable on the latest generation multicore
CPUs with the use of the best software optimization methods. In this article, a
new tracking algorithm based on the Hough transform will be evaluated for the
first time on a multi-core Intel Xeon E5-2697v2 CPU, an NVIDIA Tesla K20c GPU,
and an Intel \xphi\ 7120 coprocessor. Preliminary time performance will be
presented.


title:
Majorana fermions in quasi-1D and higher dimensional ultracold fermionic
  optical lattices

abstract:
  We show that Majorana fermions (MFs) exist in two- and three-dimensional
(2D,3D) fermionic optical lattices with strictly 1D spin-orbit coupling (SOC)
which has already been realized in ex- periments. For a quasi-1D topological
BCS superfluid, there are multiple MFs at each end which are topologically
protected by a chiral symmetry. In the generalization to higher dimensions, the
multiple MFs form a zero energy flat band. An additional experimentally tunable
in-plane Zeeman field drives the system to a topological Fulde-Ferrell (FF)
superfluid phase. We find that even though the multiple MFs are robust against
the in-plane Zeeman field if the order parameters at the different chains are
enforced to be identical, they are destroyed in the self-consistently obtained
FF phase where the order parameters are inhomogeneous on the boundaries. Our
results are useful to guide the experimentalists on searching for MFs in the
context of ultracold fermionic atoms.


title: Coloring intersection graphs of arc-connected sets in the plane

abstract:
  A family of sets in the plane is simple if the intersection of its any
subfamily is arc-connected, and it is pierced by a line $L$ if the intersection
of its any member with $L$ is a nonempty segment. It is proved that the
intersection graphs of simple families of compact arc-connected sets in the
plane pierced by a common line have chromatic number bounded by a function of
their clique number.


title:
Stochastic Hyperbolic Systems, Small Perturbations and Pathwise
  Approximation

abstract:
  This paper is devoted to the study of hyperbolic systems of linear partial
differential equations perturbed by a Brownian motion. The existence and
uniqueness of solutions are proved by an energy method. The specific features
of this class of stochastic partial differential equations are highlighted and
the comparison with standard existence results for SPDEs is discussed. The
small perturbations problem is studied and a large deviation principle is
stated. A pathwise approximation result, similar to the stochastic differential
equations case, is established, with an application to a support theorem.


title: Controlling unstable chaos: Stabilizing chimera states by feedback

abstract:
  We present a control scheme that is able to find and stabilize an unstable
chaotic regime in a system with a large number of interacting particles. This
allows us to track a high dimensional chaotic attractor through a bifurcation
where it loses its attractivity. Similar to classical delayed feedback control,
the scheme is non-invasive, however, only in an appropriately relaxed sense
considering the chaotic regime as a statistical equilibrium displaying random
fluctuations as a finite size effect. We demonstrate the control scheme for
so-called chimera states, which are coherence-incoherence patterns in coupled
oscillator systems. The control makes chimera states observable close to
coherence, for small numbers of oscillators, and for random initial conditions.


title: Atomic Fock State Preparation Using Rydberg Blockade

abstract:
  We use coherent excitation of 3-16 atom ensembles to demonstrate collective
Rabi flopping mediated by Rydberg blockade. Using calibrated atom number
measurements, we quantitatively confirm the expected $\sqrt{N}$ Rabi frequency
enhancement to within 4%. The resulting atom number distributions are
consistent with essentially perfect blockade. We then use collective Rabi $\pi$
pulses to produce ${\cal N}=1,2$ atom number Fock states with fidelities of 62%
and 48% respectively. The ${\cal N}=2$ Fock state shows the collective Rabi
frequency enhancement without corruption from atom number fluctuations.


title: The starred Dixmier's conjecture

abstract:
  Dixmier's famous question says the following: Is every algebra endomorphism
of the first Weyl algebra, $A_1(F)$, where $F$ is a zero characteristic field,
an automorphism? Let $\alpha$ be the exchange involution on $A_1(F)$:
$\alpha(x)= y$, $\alpha(y)= x$. An $\alpha$-endomorphism of $A_1(F)$ is an
endomorphism which preserves the involution $\alpha$. Then one may ask the
following question, which may be called the "$\alpha$-Dixmier's problem $1$" or
the "starred Dixmier's problem $1$": Is every $\alpha$-endomorphism of $A_1(F)$
an automorphism?


title:
Observation of Floquet-Bloch states on the surface of a topological
  insulator

abstract:
  The unique electronic properties of the surface electrons in a topological
insulator are protected by time-reversal symmetry. Circularly polarized light
naturally breaks time-reversal symmetry, which may lead to an exotic surface
quantum Hall state. Using time- and angle-resolved photoemission spectroscopy,
we show that an intense ultrashort mid-infrared pulse with energy below the
bulk band gap hybridizes with the surface Dirac fermions of a topological
insulator to form Floquet-Bloch bands. These photon dressed surface bands
exhibit polarization-dependent band gaps at avoided crossings. Circularly
polarized photons induce an additional gap at the Dirac point, which is a
signature of broken time-reversal symmetry on the surface. These observations
establish the Floquet-Bloch bands in solids and pave the way for optical
manipulation of topological quantum states of matter.


title: The Entropy of a Vacuum: What Does the Covariant Entropy Count?

abstract:
  We argue that a unitary description of the formation and evaporation of a
black hole implies that the Bekenstein-Hawking entropy is the "entropy of a
vacuum": the logarithm of the number of possible independent ways in which
quantum field theory on a fixed classical spacetime background can emerge in a
full quantum theory of gravity. In many cases, the covariant entropy counts
this entropy--the degeneracy of emergent quantum field theories in full quantum
gravity--with the entropy of particle excitations in each quantum field theory
giving only a tiny perturbation. In the Rindler description of a (black hole)
horizon, the relevant vacuum degrees of freedom manifest themselves as an extra
hidden quantum number carried by the states representing the second exterior
region; this quantum number is invisible in the emergent quantum field theory.
In a distant picture, these states arise as exponentially degenerate ground and
excited states of the intrinsically quantum gravitational degrees of freedom on
the stretched horizon. The formation and evaporation of a black hole involve
processes in which the entropy of collapsing matter is transformed into that of
a vacuum and then to that of final-state Hawking radiation. In the intermediate
stage of this evolution, entanglement between the vacuum and (early) Hawking
radiation develops, which is transferred to the entanglement among final-state
Hawking quanta through the evaporation process. The horizon is kept smooth
throughout the evolution; in particular, no firewall develops. Similar
considerations also apply for cosmological horizons, for example for the
horizon of a meta-stable de-Sitter space.


title:
Hunting The Most Distant Stars in the Milky Way: Methods and Initial
  Results

abstract:
  We present a new catalog of 404 M giant candidates found in the UKIRT
Infrared Deep Sky Survey (UKIDSS). The 2,400 deg$^2$ available in the UKIDSS
Large Area Survey Data Release 8 resolve M giants through a volume four times
larger than that of the entire Two Micron All Sky Survey. Combining
near-infrared photometry with optical photometry and proper motions from the
Sloan Digital Sky Survey yields an M giant candidate catalog with less M dwarf
and quasar contamination than previous searches for similarly distant M giants.
Extensive follow-up spectroscopy of this sample will yield the first map of our
Galaxy's outermost reaches over a large area of sky. Our initial spectroscopic
follow-up of $\sim$ 30 bright candidates yielded the positive identification of
five M giants at distances $\sim 20-90$ kpc. Each of these confirmed M giants
have positions and velocities consistent with the Sagittarius stream. The
fainter M giant candidates in our sample have estimated photometric distances
$\sim 200$ kpc (assuming $[Fe/H]$ = 0.0), but require further spectroscopic
verification. The photometric distance estimates extend beyond the Milky Way's
virial radius, and increase by $\sim 50\%$ for each 0.5 dex decrease in assumed
$[Fe/H]$. Given the number of M giant candidates, initial selection efficiency,
and volume surveyed, we loosely estimate that at least one additional
Sagittarius-like accretion event could have contributed to the hierarchical
build-up of the Milky Way's outer halo.


title: Probability distributions for Poisson processes with pile-up

abstract:
  In this paper, two parametric probability distributions capable to describe
the statistics of X-ray photon detection by a CCD are presented. They are
formulated from simple models that account for the pile-up phenomenon, in which
two or more photons are counted as one. These models are based on the Poisson
process, but they have an extra parameter which includes all the detailed
mechanisms of the pile-up process that must be fitted to the data statistics
simultaneously with the rate parameter. The new probability distributions, one
for number of counts per time bins (Poisson-like), and the other for waiting
times (exponential-like) are tested fitting them to statistics of real data,
and between them through numerical simulations, and their results are analyzed
and compared. The probability distributions presented here can be used as
background statistical models to derive likelihood functions for statistical
methods in signal analysis.


title:
Derivation of a four-spinor Dirac-like equation for the helium atom and
  an approximate ground state solution

abstract:
  We present a new analysis of the connection between the classical
conservation theorems and the role played by the Dirac matrices in order to
obtain a four spinor version of the Dirac equation for the two electrons bound
problem. The separation of the set of equations in its angular and radial parts
is done and an asymptotic solution for the radial system of equations is
discussed for the ground state of the atom.


title:
Interlimb neural connection is not required for gait transition in
  quadruped locomotion

abstract:
  Quadrupeds transition spontaneously to various gait patterns (e.g., walk,
trot, pace, gallop) in response to the locomotion speed. The generation of
these gait patterns has been the subject of debate for a long time. We propose
a coupled oscillator model that is coupled with the physical interactions of
the body. The results of this study showed that the gait pattern transitions
spontaneously to walking/trotting/pacing/bounding in manner similar to that of
real quadruped animals when the resonating portion of the body is changed
according to the speed of leg movement. We also observed that pacing is
expressed exclusively instead of trotting by changing the physical
characteristics. In addition to leading to understanding of the principles of
locomotion in living things, the coupled oscillator model proposed in this
study is expected to lead to the creation of a legged robot that can select an
energy-efficient gait and transition to it spontaneously.


title: James Fergason, a Pioneer in Advancing of Liquid Crystal Technology

abstract:
  James Lee Fergason (1934 - 2008) focused his research on the liquid crystals.
His studies correspond to a relevant part of the history of soft matter science
and technology of liquid crystals. Here a discussion of some of his researches.


title: Finite-dimensional representations of the elliptic modular double

abstract:
  We investigate the kernel space of an integral operator M(g) depending on the
"spin" g and describing an elliptic Fourier transformation. The operator M(g)
is an intertwiner for the elliptic modular double formed from a pair of
Sklyanin algebras with the parameters $\eta$ and $\tau$, Im$ \tau>0$,
Im$\eta>0$. For two-dimensional lattices $g=n\eta + m\tau/2$ and $g=1/2+n\eta +
m\tau/2$ with incommensurate $1, 2\eta,\tau$ and integers $n,m>0$, the operator
M(g) has a finite-dimensional kernel that consists of the products of theta
functions with two different modular parameters and is invariant under the
action of generators of the elliptic modular double.


title:
The impact of baryonic processes on the two-point correlation functions
  of galaxies, subhaloes and matter

abstract:
  The observed clustering of galaxies and the cross-correlation of galaxies and
mass provide important constraints on both cosmology and models of galaxy
formation. Even though the dissipation and feedback processes associated with
galaxy formation are thought to affect the distribution of matter, essentially
all models used to predict clustering data are based on collisionless
simulations. Here, we use large hydrodynamical simulations to investigate how
galaxy formation affects the autocorrelation functions of galaxies and
subhaloes, as well as their cross-correlation with matter. We show that the
changes due to the inclusion of baryons are not limited to small scales and are
even present in samples selected by subhalo mass. Samples selected by subhalo
mass cluster ~10% more strongly in a baryonic run on scales r > 1Mpc/h, and
this difference increases for smaller separations. While the inclusion of
baryons boosts the clustering at fixed subhalo mass on all scales, the sign of
the effect on the cross-correlation of subhaloes with matter can vary with
radius. We show that the large-scale effects are due to the change in subhalo
mass caused by the strong feedback associated with galaxy formation and may
therefore not affect samples selected by number density. However, on scales r <
r_vir significant differences remain after accounting for the change in subhalo
mass. We conclude that predictions for galaxy-galaxy and galaxy-mass clustering
from models based on collisionless simulations will have errors greater than
10% on sub-Mpc scales, unless the simulation results are modified to correctly
account for the effects of baryons on the distributions of mass and satellites.


title: Stellar feedback by radiation pressure and photoionization

abstract:
  The relative impact of radiation pressure and photoionization feedback from
young stars on surrounding gas is studied with hydrodynamic radiative transfer
(RT) simulations. The calculations focus on the single-scattering (direct
radiation pressure) and optically thick regime, and adopt a moment-based
RT-method implemented in the moving-mesh code AREPO. The source luminosity, gas
density profile and initial temperature are varied. At typical temperatures and
densities of molecular clouds, radiation pressure drives velocities of order
~20 km/s over 1-5 Myr; enough to unbind the smaller clouds. However, these
estimates ignore the effects of photoionization that naturally occur
concurrently. When radiation pressure and photoionization act together, the
latter is substantially more efficient, inducing velocities comparable to the
sound speed of the hot ionized medium (10-15 km/s) on timescales far shorter
than required for accumulating similar momentum with radiation pressure. This
mismatch allows photoionization to dominate the feedback as the heating and
expansion of gas lowers the central densities, further diminishing the impact
of radiation pressure. Our results indicate that a proper treatment of the
impact of young stars on the interstellar medium needs to primarily account for
their ionization power whereas direct radiation pressure appears to be a
secondary effect. This conclusion may change if extreme boosts of the radiation
pressure by photon trapping are assumed.


title:
Evidence for an Interaction in the Nearest Starbursting Dwarf Irregular
  Galaxy IC 10

abstract:
  Using deep 21-cm HI data from the Green Bank Telescope we have detected an
~18.3 kpc-long gaseous extension associated with the starbursting dwarf galaxy
IC 10. The newly-found feature stretches 1.3 deg to the northwest and has a
large radial velocity gradient reaching to ~65 km/s lower than the IC 10
systemic velocity. A region of higher column density at the end of the
extension that possesses a coherent velocity gradient (~10 km/s across ~26
arcmin) transverse to the extension suggests rotation and may be a satellite
galaxy of IC 10. The HI mass of IC 10 is 9.5x10^7 (d/805 kpc)^2 Msun and the
mass of the new extension is 7.1x10^5 (d/805 kpc)^2 Msun. An IC 10-M31 orbit
using known radial velocity and proper motion values for IC 10 show that the HI
extension is inconsistent with the trailing portion of the orbit so that an
M31-tidal or ram pressure origin seems unlikely. We argue that the most
plausible explanation for the new feature is that it is the result of a recent
interaction (and possible late merger) with another dwarf galaxy. This
interaction could not only have triggered the origin of the recent starburst in
IC 10, but could also explain the existence of previously-found
counter-rotating HI gas in the periphery of the IC 10 which was interpreted as
originating from primordial gas infall.


title: A Simple Gravitational Lens Model For Cosmic Voids

abstract:
  We present a simple gravitational lens model to illustrate the ease of using
the embedded lensing theory when studying cosmic voids. It confirms the
previously used repulsive lensing models for deep voids. We start by estimating
magnitude fluctuations and weak lensing shears of background sources lensed by
large voids. We find that sources behind large ($\sim$$90\,\rm Mpc$) and deep
voids (density contrast about $-0.9$) can be magnified or demagnified with
magnitude fluctuations of up to $\sim$$0.05\,\rm mag$ and that the weak-lensing
shear can be up to the $\sim$$10^{-2}$ level in the outer regions of large
voids. Smaller or shallower voids produce proportionally smaller effects. We
investigate the "wiggling" of the primary cosmic microwave background (CMB)
temperature anisotropies caused by intervening cosmic voids. The void-wiggling
of primary CMB temperature gradients is of the opposite sign to that caused by
galaxy clusters. Only extremely large and deep voids can produce wiggling
amplitudes similar to galaxy clusters, $\sim$$\rm 15\,\mu K$ by a large void of
radius $\sim$$4^\circ$ and central density contrast $-0.9$ at redshift 0.5
assuming a CMB background gradient of $\sim$$\rm10\,\mu K\, arcmin^{-1}$. The
dipole signal is spread over the entire void area, and not concentrated at the
lens' center as it is for clusters. Finally we use our model to simulate CMB
sky maps lensed by large cosmic voids. Our embedded theory can easily be
applied to more complicated void models and used to study gravitational lensing
of the CMB, to probe dark-matter profiles, to reduce the lensing-induced
systematics in supernova Hubble diagrams, as well as study the integrated
Sachs-Wolfe effect.


title: The Dynamical Properties of Virgo Cluster Disk Galaxies

abstract:
  By virtue of its proximity, the Virgo Cluster is an ideal laboratory for
testing our understanding structure formation in the Universe. In this spirit,
we present a dynamical study Virgo galaxies as part of the Spectroscopic and
H-band Imaging of Virgo (SHIVir) survey. H$\alpha$ rotation curves (RC) for our
gas-rich galaxies were modelled with a multi-parameter fit function from which
various velocity measurements were inferred. Our study takes advantage of
archival and our own new data as we aim to compile the largest Tully-Fisher
relation (TFR) for a cluster to date. Extended velocity dispersion profiles
(VDP) are integrated over varying aperture sizes to extract representative
velocity dispersions (VDs) for gas-poor galaxies. Considering the lack of a
common standard for the measurement of a fiducial galaxy VD in the literature,
we rectify this situation by determining the radius at which the measured VD
yields the tightest Fundamental Plane (FP). We found that radius to be at least
1 $R_{\rm e}$, which exceeds the extent of most dispersion profiles in other
works.


title:
Oblique Shock Breakout in Supernovae and Gamma-Ray Bursts: I. Dynamics
  and Observational Implications

abstract:
  In a non-spherical stellar explosion, non-radial motions become important
near the stellar surface. For realistic deviations from spherical symmetry,
non-radial flow dramatically alters the dynamics and emission of shock
emergence on a significant fraction of the surface. The breakout flash is
stifled, ejecta speeds are limited, and matter is cast sideways. Non-radial
ejection allows for collisions outside the star, which may engender a new type
of transient. Strongly oblique breakouts are most easily produced in compact
stellar progenitors, such as white dwarfs and stripped-envelope core collapse
supernovae.
  We study the shock structure and post-shock acceleration using conservation
laws, a similarity analysis, and an approximate theory for oblique shocks. The
shock is likely to extend vertically from the stellar surface, then kink before
joining a deep asymptotic solution. Outflow from the region crossed by an
oblique shock is probably unsteady and may affect the surface ahead of the main
shock. We comment on the implications for several notable explosions in which
the non-spherical dynamics described in this paper are likely to play an
important role. We also briefly consider relativistic and superluminal pattern
speeds.


title: A Cosmological Super-Bounce

abstract:
  We study a model for a non-singular cosmic bounce in N=1 supergravity, based
on supergravity versions of the ghost condensate and cubic Galileon scalar
field theories. The bounce is preceded by an ekpyrotic contracting phase which
prevents the growth of anisotropies in the approach to the bounce, and allows
for the generation of scale-invariant density perturbations that carry over
into the expanding phase of the universe. We present the conditions required
for the bounce to be free of ghost excitations, as well as the tunings that are
necessary in order for the model to be in agreement with cosmological
observations. All of these conditions can be met. Our model thus provides a
proof-of-principle that non-singular bounces are viable in supergravity,
despite the fact that during the bounce the null energy condition is violated.


title:
Cosmological Parameter Determination in Free-Form Strong Gravitational
  Lens Modeling

abstract:
  We develop a novel statistical strong lensing approach to probe the
cosmological parameters by exploiting multiple redshift image systems behind
galaxies or galaxy clusters. The method relies on free-form mass inversion of
strong lenses and does not need any additional information other than
gravitational lensing. Since in free-form lensing the solution space is a
high-dimensional convex polytope, we consider Bayesian model comparison
analysis to infer the cosmological parameters. The volume of the solution space
is taken as a tracer of the probability of the underlying cosmological
assumption. In contrast to parametric mass inversions, our method accounts for
the mass-sheet degeneracy, which implies a degeneracy between the steepness of
the profile and the cosmological parameters. Parametric models typically break
this degeneracy, introducing hidden priors to the analysis that contaminate the
inference of the parameters. We test our method with synthetic lenses, showing
that it is able to infer the assumed cosmological parameters. Applied to the
CLASH clusters, the method might be competitive with other probes.


title: On the Viability of Thermal Well-Tempered Dark Matter in SUSY GUTs

abstract:
  In a scenario with heavy supersymmetric sfermions and decoupled
supersymmetric Higgs sector, a well tempered neutralino is the remaining
candidate for thermal single-component sub-TeV dark matter. Well tempered
neutralinos are studied in the context of supersymmetric grand unified theories
with third family Yukawa coupling unification. A global chi^2 analysis is
performed, including the observables MW, MZ, GF, alpha_em, alpha_s(MZ), Mt,
mb(mb), Mtau, b -> s gamma, BR(Bs -> mu^+ mu^-), Mh and Omegah^2. Tensions in
simultaneously fitting the Higgs and bottom quark masses while also avoiding
gluino mass bounds from the LHC disfavors light Higgsinos with mass < 500 GeV,
ruling out light Bino/Higgsino dark matter candidates. Bino/Wino/Higgsino and
Bino/Wino candidates fare somewhat better although they are fine-tuned and
require departure from GUT scale gaugino mass universality (the example chosen
here is the mixed modulus-anomaly pattern). Implications for dark matter direct
detection of these models as well as collider signatures are briefly discussed.
Independent of the thermal dark matter viability, these models will be severely
constrained by the absence of a gluino at the next run of LHC.


title:
Modeling AGN Feedback in Cool-Core Clusters: The Formation of Cold
  Clumps

abstract:
  We perform high-resolution (15-30 pc) adaptive mesh simulations to study the
impact of momentum-driven AGN feedback in cool-core clusters, focusing in this
paper on the formation of cold clumps. The feedback is jet-driven with an
energy determined by the amount of cold gas within 500 pc of the SMBH. When the
intra-cluster medium (ICM) in the core of the cluster becomes marginally stable
to radiative cooling, with the thermal instability to the free-fall timescale
ratio t_{TI}/t_{ff} < 3-10, cold clumps of gas start to form along the
propagation direction of the AGN jets. By tracing the particles in the
simulations, we find that these cold clumps originate from low entropy (but
still hot) gas that is accelerated by the jet to outward radial velocities of a
few hundred km/s. This gas is out of hydrostatic equilibrium and so can cool.
The clumps then grow larger as they decelerate and fall towards the center of
the cluster, eventually being accreted onto the super-massive black hole. The
general morphology, spatial distribution and estimated H{\alpha} morphology of
the clumps are in reasonable agreement with observations, although we do not
fully replicate the filamentary morphology of the clumps seen in the
observations, probably due to missing physics.


title: Nuclear coups: dynamics of black holes in galaxy mergers

abstract:
  We study the dynamical evolution of supermassive black holes (BHs) in merging
galaxies on scales of hundreds of kpc to 10 pc, to identify the physical
processes that aid or hinder the orbital decay of BHs. We present
hydrodynamical simulations of galaxy mergers with a resolution of $\leq$20 pc,
chosen to accurately track the motion of the nuclei and provide a realistic
environment for the evolution of the BHs. We find that, during the late stages
of the merger, tidal shocks inject energy in the nuclei, causing one or both
nuclei to be disrupted and leaving their BH `naked', without any bound gas or
stars. In many cases, the nucleus that is ultimately disrupted is that of the
larger galaxy (`nuclear coup'), as star formation grows a denser nuclear cusp
in the smaller galaxy. We supplement our simulations with an analytical
estimate of the orbital-decay time required for the BHs to form a binary at
unresolved scales, due to dynamical friction. We find that, when a nuclear coup
occurs, the time-scale is much shorter than when the secondary's nucleus is
disrupted, as the infalling BH is more massive, and it also finds itself in a
denser stellar environment.


title:
Tracing the Mass Growth and Star Formation Rate Evolution of Massive
  Galaxies from z~6 to z~1 in the Hubble Ultra-Deep Field

abstract:
  We present an analysis of $\sim$1500 H160-selected photometric galaxies
detected to a limiting magnitude of 27.8 in the HUDF, using imaging from the
HST WFC3/IR camera in combination with archival UV, optical, and NIR imaging.
We fit photometric redshifts and stellar population estimates for all galaxies
with well-determined Spitzer IRAC fluxes, allowing for the determination of the
cumulative mass function within the range $1<z<6$. By selecting samples of
galaxies at a constant cumulative number density, we explore the co-evolution
of stellar masses and star formation rates from z$\sim$6. We find a steady
increase in the SFRs of galaxies at constant number density from z$\sim$6 to
z$\sim$3. The peak epoch of star formation is found to shift to later times for
galaxies with increasing number densities, in agreement with the expectations
from cosmic downsizing. The observed SFRs can fully account for the mass growth
to z$\sim$2 amongst galaxies with cumulative number densities greater than
10$^{-3.5}$ Mpc$^{-3}$. For galaxies with a lower constant number density we
find the observed stellar masses are $\sim$3 times greater than that which may
be accounted for by the observed star formation alone at late times, implying
that growth from mergers plays an important role at $z<2$. We additionally
observe a decreasing sSFR, equivalent to approximately one order of magnitude,
from z$\sim$6 to z$\sim$2 amongst galaxies with number densities less than
10$^{-3.5}$ Mpc$^{-3}$ along with significant evidence that at any redshift the
sSFR is higher for galaxies at higher number density. The combination of these
findings can qualitatively explain the previous findings of a sSFR plateau at
high redshift. Tracing the evolution of the fraction of quiescent galaxies for
samples matched in cumulative number density over this redshift range, we find
no unambiguous examples of quiescent galaxies at $z>4$.


title: HerMES: Candidate High-Redshift Galaxies Discovered with Herschel/SPIRE

abstract:
  We present a method for selecting $z>4$ dusty, star forming galaxies (DSFGs)
using Herschel/SPIRE 250/350/500 $\mu m$ flux densities to search for red
sources. We apply this method to 21 deg$^2$ of data from the HerMES survey to
produce a catalog of 38 high-$z$ candidates. Follow-up of the first 5 of these
sources confirms that this method is efficient at selecting high-$z$ DSFGs,
with 4/5 at $z=4.3$ to $6.3$ (and the remaining source at $z=3.4$), and that
they are some of the most luminous dusty sources known. Comparison with
previous DSFG samples, mostly selected at longer wavelengths (e.g., 850 $\mu
m$) and in single-band surveys, shows that our method is much more efficient at
selecting high-$z$ DSFGs, in the sense that a much larger fraction are at
$z>3$. Correcting for the selection completeness and purity, we find that the
number of bright ($S_{500\,\mu m} \ge 30$ mJy), red Herschel sources is $3.3
\pm 0.8$ deg$^{-2}$. This is much higher than the number predicted by current
models, suggesting that the DSFG population extends to higher redshifts than
previously believed. If the shape of the luminosity function for high-$z$ DSFGs
is similar to that at $z\sim2$, rest-frame UV based studies may be missing a
significant component of the star formation density at $z=4$ to $6$, even after
correction for extinction.


title: Jet Observables Without Jet Algorithms

abstract:
  We introduce a new class of event shapes to characterize the jet-like
structure of an event. Like traditional event shapes, our observables are
infrared/collinear safe and involve a sum over all hadrons in an event, but
like a jet clustering algorithm, they incorporate a jet radius parameter and a
transverse momentum cut. Three of the ubiquitous jet-based observables---jet
multiplicity, summed scalar transverse momentum, and missing transverse
momentum---have event shape counterparts that are closely correlated with their
jet-based cousins. Due to their "local" computational structure, these jet-like
event shapes could potentially be used for trigger-level event selection at the
LHC. Intriguingly, the jet multiplicity event shape typically takes on
non-integer values, highlighting the inherent ambiguity in defining jets. By
inverting jet multiplicity, we show how to characterize the transverse momentum
of the n-th hardest jet without actually finding the constituents of that jet.
Since many physics applications do require knowledge about the jet
constituents, we also build a hybrid event shape that incorporates (local) jet
clustering information. As a straightforward application of our general
technique, we derive an event-shape version of jet trimming, allowing
event-wide jet grooming without explicit jet identification. Finally, we
briefly mention possible applications of our method for jet substructure
studies.


title:
Spitzer and z' Secondary Eclipse Observations of the Highly Irradiated
  Transiting Brown Dwarf KELT-1b

abstract:
  We present secondary eclipse observations of the highly irradiated transiting
brown dwarf KELT-1b. These observations represent the first constraints on the
atmospheric dynamics of a highly irradiated brown dwarf, and the atmospheres of
irradiated giant planets at high surface gravity. Using the Spitzer Space
Telescope, we measure secondary eclipse depths of 0.195+/-0.010% at 3.6um and
0.200+/-0.012% at 4.5um. We also find tentative evidence for the secondary
eclipse in the z' band with a depth of 0.049+/-0.023%. These measured eclipse
depths are most consistent with an atmosphere model in which there is a strong
substellar hotspot, implying that heat redistribution in the atmosphere of
KELT-1b is low. While models with a more mild hotspot or even with dayside heat
redistribution are only marginally disfavored, models with complete heat
redistribution are strongly ruled out. The eclipse depths also prefer an
atmosphere with no TiO inversion layer, although a model with TiO inversion is
permitted in the dayside heat redistribution case, and we consider the
possibility of a day-night TiO cold trap in this object. For the first time, we
compare the IRAC colors of brown dwarfs and hot Jupiters as a function of
effective temperature. Importantly, our measurements reveal that KELT-1b has a
[3.6]-[4.5] color of 0.07+/-0.11, identical to that of isolated brown dwarfs of
similarly high temperature. In contrast, hot Jupiters generally show redder
[3.6]-[4.5] colors of ~0.4, with a very large range from ~0 to ~1. Evidently,
despite being more similar to hot Jupiters than to isolated brown dwarfs in
terms of external forcing of the atmosphere by stellar insolation, KELT-1b has
an atmosphere most like that of other brown dwarfs. This suggests that surface
gravity is very important in controlling the atmospheric systems of substellar
mass bodies.