title:
Rigorous asymptotic analysis of buckling of thin-walled cylinders under
  axial compression

abstract:
  Using rigorous constitutive linearization of second variation introduced in
[6] we study weak stability of homogeneous deformation of the axially
compressed circular cylindrical shell, regarded as a 3-dimensional hyperelastic
body. We show that such deformation becomes weakly unstable at the citical load
that coincides with value of the bifurcation load in von-K\'arm\'an-Donnel
shell theory. We also show that the linear bifurcation modes described by the
Koiter circle [11] minimize the second variation asymptotically. The key
ingredients of our analysis are the asymptoticaly sharp estimates of the Korn
constant for cylindrical shells and Korn-like inequalities on components of the
deformation gradient tensor in cylindrical coordinates. The notion of buckling
equivalence introduced in [6] is developed further and becomes central in this
work. A link between features of this theory and sensitivity of the critical
load to imprefections of load and shape is conjectured.


title: Optimal learning with $Q$-aggregation

abstract:
  We consider a general supervised learning problem with strongly convex and
Lipschitz loss and study the problem of model selection aggregation. In
particular, given a finite dictionary functions (learners) together with the
prior, we generalize the results obtained by Dai, Rigollet and Zhang [Ann.
Statist. 40 (2012) 1878-1905] for Gaussian regression with squared loss and
fixed design to this learning setup. Specifically, we prove that the
$Q$-aggregation procedure outputs an estimator that satisfies optimal oracle
inequalities both in expectation and with high probability. Our proof
techniques somewhat depart from traditional proofs by making most of the
standard arguments on the Laplace transform of the empirical process to be
controlled.


title: A Physical Model for the Revised Blazar Sequence

abstract:
  The blazar sequence is reflected in a correlation of the peak luminosity
versus peak frequency of the synchrotron component of blazars. This correlation
has been considered one of the fundamental pieces of evidence for the existence
of a continuous sequence that includes low-power BL Lacertae objects through
high-power flat spectrum radio quasars. A correlation between the Compton domi-
nance, the ratio of the Compton to synchrotron luminosities, and the peak
synchrotron frequency is another piece of evidence for the existence of the
blazar sequence explored by Fossati et al. (1998). Since that time, however, it
has essentially been ignored. We explore this correlation with a sample based
on the second LAT AGN catalog (2LAC), and show that is is particularly
important, since it is independent of redshift. We reproduce the trends in our
sample with a simple model that in- cludes synchrotron and Compton cooling in
the slow- and fast-cooling regimes, and angle-dependent effects.


title: Reaction-diffusion model Monte Carlo simulations on the GPU

abstract:
  We created an efficient algorithm suitable for graphics processing units
(GPUs) to perform Monte Carlo simulations of a subset of reaction-diffusion
models. The algorithm uses techniques that are specific to GPU programming, and
combines these with the multispin technique known from CPU programming to
create one of the fastest algorithms for reaction-diffusion models. As an
example, the algorithm is applied to the pair contact process with diffusion
(PCPD). Compared to a simple algorithm on the CPU, our GPU algorithm is
approximately 4000 times faster. If we compare the performance of the GPU
algorithm, between the GPU and CPU, we find a speed-up of about 130x.


title: Ab Initio Lattice Dynamics and Elastic Constants of ZrC

abstract:
  Ab initio calculations and a direct method are applied to derive the phonon
dispersion relations and phonon density of states for the ZrC crystal. The
results are in good agreement with neutron scattering data. The force constants
are determined from the Hellmann-Feynman forces induced by atomic displacements
in a 2x2x2 supercell. The elastic constants are found using the deformation
method and successfully compare with experimental data.


title:
Event by event di-hadron correlations in Pb-Pb 2.76 TeV collisions from
  the ALICE experiment

abstract:
  The large multiplicities at the LHC may permit flow harmonics to be
determined on an event by event basis in Pb-Pb collisions. We extract these
harmonics from event by event di-hadron correlations. Within a fine centrality
bin, we find the correlation function varies substantially on an event by event
basis, indicating large fluctuations in the initial conditions for a given
impact parameter. Such large fluctuations lead to some events being highly
triangular or highly elliptical, where the angular correlation function is
completely dominated by the respective second and third Fourier harmonics. We
will show unfolded $v_{2}$ distributions for various centralities, and
implications for our understanding of the initial conditions.


title: Supersymmetric SO(10) GUTs with sliding scales

abstract:
  We construct lists of supersymmetric models with extended gauge groups at
intermediate steps, all of which are based on SO(10) unification. We consider
three different kinds of setups: (i) The model has exactly one additional
intermediate scale with a left-right (LR) symmetric group; (ii) SO(10) is
broken to the LR group via an intermediate Pati-Salam (PS) scale; and (iii) the
LR group is broken into $SU(3)_{c} \times SU(2)_{L} \times U(1)_{R} \times
U(1)_{B-L}$, before breaking to the SM group. We use sets of conditions, which
we call the "sliding mechanism", which yield unification with the extended
gauge group(s) allowed at arbitrary intermediate energy scales. All models thus
can have new gauge bosons within the reach of the LHC, in principle. We apply
additional conditions, such as perturbative unification, renormalizability and
anomaly cancellation and find that, despite these requirements, for the ansatz
(i) with only one additional scale still around 50 different variants exist
that can have an LR symmetry below 10 TeV. For the more complicated schemes
(ii) and (iii) literally thousands of possible variants exist, and for scheme
(ii) we have also found variants with very low PS scales. We also discuss
possible experimental tests of the models from measurements of SUSY masses.
Assuming mSugra boundary conditions we calculate certain combinations of soft
terms, called "invariants", for the different classes of models. Values for all
the invariants can be classified into a small number of sets, which contain
information about the class of models and, in principle, the scale of
beyond-MSSM physics, even in case the extended gauge group is broken at an
energy beyond the reach of the LHC.


title: Benford-Newcomb Subsequences for Fraud Detection

abstract:
  Benford's law is frequently used to evaluate the likihood that data is
misrepresentative. Typically statistical tests measure the likihood. Another
method of employing Benford's law is to compare the frequency of leading digits
to the probabilities of leading digits over a subset of the natural numbers.
This paper proposes using the probabilities of leading digits from uniform,
natural numbers to establish interval criteria for when to look more closely
into the possibility of misrepresentative data.


title:
Turbostratic graphitic microstructures: electronically decoupled
  multilayer graphene devices with robust high charge carrier mobility

abstract:
  Carbon nanomaterials continue to amaze scientists due to their exceptional
physical properties. Recently there have been theoretical predictions and first
reports on graphene multilayers, where, due to the rotation of the stacked
layers, outstanding electronic properties are retained while the susceptibility
to degradation and mechanical stress is strongly reduced due to the multilayer
nature. Here we show that fully turbostratic multilayer graphitic
microstructures combine the high charge carrier mobilities necessary for
advanced electronic and spintronic devices with the robustness of graphitic
structures. Structural characterization of disk-shaped graphitic
microstructures using Raman spectroscopy and Transmission Electron Microscopy
(TEM) reveals Moir\'e and diffraction patterns corroborating their turbostratic
nature. Electronic transport characterization yields reproducible high
mobilities > 105 cm^2(Vs)^(-1) independent of the disks thickness, which is a
direct consequence of the electronic decoupling induced by the turbostratic
stacking.


title:
Growth of Self Organized Eutectic Fibers from LiF-Rare Earth Fluoride
  Systems

abstract:
  Eutectic fibers consisting of an ordered arrangement of LiF fibrils inside a
LiREF4 matrix (RE = Y, Gd) can be grown with the micro-pulling-down method at
sufficiently large pulling rate exceeding 120 mm/h. The distance between
individual fibrils could be scaled down to 1 micrometer at 300 mm/h pulling.
LiF-LiYF4 has stronger tendency to form facetted eutectic colonies than
LiF-LiGdF4, explained by the larger entropy of melting of the former.


title:
Study of the $\Lambda p$ Interaction Close to the $\Sigma^+n$ and
  $\Sigma^0p$ Thresholds

abstract:
  The $\Lambda p$ interaction close to the $\Sigma N$ threshold is considered.
Specifically, the pronounced structure seen in production reactions like $K^-d
\to \pi^- \Lambda p$ and $pp\to K^+ \Lambda p$ around the $\Sigma N$ threshold
is analyzed. Modern interaction models of the coupled $\Lambda N - \Sigma N$
systems generate such a structure either due to the presence of a
(deuteron-like) unstable bound state or of an inelastic virtual state. % A
determination of the position of the prominent peak as observed in various
experiments for the two aforementioned reactions leads to values that agree
quite well with each other. Furthermore, the deduced mean value of $2128.7\pm
0.3$ MeV for the peak position coincides practically with the threshold energy
of the $\Sigma^+ n$ channel. This supports the interpretation of the structure
as a genuine cusp, signaling an inelastic virtual state in the $^3S_1-^3D_1$
partial wave of the $\Sigma N$ isospin 1/2 channel. % There is also evidence
for a second peak (or shoulder) in the data sets considered which appears at
roughly 10-15 MeV above the $\Sigma N$ threshold. However, its concrete
position varies significantly from data set to data set and, thus, a
theoretical interpretation is difficult.


title:
Construction of two-dimensional quantum field models through
  Longo-Witten endomorphisms

abstract:
  We present a procedure to construct families of local, massive and
interacting Haag-Kastler nets on the two-dimensional spacetime through an
operator-algebraic method. An existence proof of local observable is given
without relying on modular nuclearity.
  By a similar technique, another family of wedge-local nets is constructed
using certain endomorphisms of conformal nets recently studied by Longo and
Witten.


title: Historical Approach to Physics according to Kant, Einstein, and Hegel

abstract:
  It is known that Einstein's conceptual base for his theory of relativity was
the philosophy formulated by Immanuel Kant. Things appear differently to
observers in different frames. However, Kant's Ding-an-Sich leads to the
existence of the absolute reference frame which is not acceptable in Einstein's
theory. It is possible to avoid this conflict using the ancient Chinese
philosophy of Taoism where two different views can co-exist in harmony. This is
not enough to explain Einstein's discovery of the mass-energy relation. The
energy-momentum relations for slow and ultra-fast particles take different
forms. Einstein was able to synthesize these two formulas to create his
energy-mass relation. Indeed, this is what Hegelianism is about in physics.
Isaac Newton synthesized open orbits for comets and closed orbits for planets
to create his second law of motion. Maxwell combined electricity and magnetism
to create his four equations to the present-day wireless world. In order to
synthesize wave and particle views of matter, Heisenberg formulated his
uncertainty principle. Relativity and quantum mechanics are the two greatest
theories formulated in the 20th Century. Efforts to synthesize these two
theories are discussed in detail.


title: Neutrality in the Graph Coloring Problem

abstract:
  The graph coloring problem is often investigated in the literature. Many
insights about many neighboring solutions with the same fitness value are
raised but as far as we know, no deep analysis of this neutrality has ever been
conducted in the literature. In this paper, we quantify the neutrality of some
hard instances of the graph coloring problem. This neutrality property has to
be detected as it impacts the search process. Indeed, local optima may belong
to plateaus that represents a barrier for local search methods. In this work,
we also aim at pointing out the interest of exploiting neutrality during the
search. Therefore, a generic local search dedicated to neutral problems, NILS,
is performed on several hard instances.


title:
On the extinction of Continuous State Branching Processes with
  catastrophes

abstract:
  We consider continuous state branching processes (CSBP) with additional
multiplicative jumps modeling dramatic events in a random environment. These
jumps are described by a L\'evy process with bounded variation paths. We
construct a process of this class as the unique solution of a stochastic
differential equation. The quenched branching property of the process allows us
to derive quenched and annealed results and to observe new asymptotic
behaviors. We characterize the Laplace exponent of the process as the solution
of a backward ordinary differential equation and establish the probability of
extinction. Restricting our attention to the critical and subcritical cases, we
show that four regimes arise for the speed of extinction, as in the case of
branching processes in random environment in discrete time and space. The
proofs are based on the precise asymptotic behavior of exponential functionals
of L\'evy processes. Finally, we apply these results to a cell infection model
and determine the mean speed of propagation of the infection.


title: A new construction of Moufang quadrangles of type E6, E7 and E8

abstract:
  In the classification of Moufang polygons by J. Tits and R. Weiss, the most
intricate case is by far the case of the exceptional Moufang quadrangles of
type E_6, E_7 and E_8, and in fact, the construction that they present is
ad-hoc and lacking a deeper explanation. We will show how tensor products of
two composition algebras can be used to construct these Moufang quadrangles in
characteristic different from 2.
  As a byproduct, we will obtain a method to construct any Moufang quadrangle
in characteristic different from two from a module for a Jordan algebra.


title:
Persistent control of a superconducting qubit by stroboscopic
  measurement feedback

abstract:
  Making a system state follow a prescribed trajectory despite fluctuations and
errors commonly consists in monitoring an observable (temperature,
blood-glucose level...) and reacting on its controllers (heater power, insulin
amount ...). In the quantum domain, there is a change of paradigm in feedback
since measurements modify the state of the system, most dramatically when the
trajectory goes through superpositions of measurement eigenstates. Here, we
demonstrate the stabilization of an arbitrary trajectory of a superconducting
qubit by measurement based feedback. The protocol benefits from the long
coherence time ($T_2>10 \mu$s) of the 3D transmon qubit, the high efficiency
(82%) of the phase preserving Josephson amplifier, and fast electronics
ensuring less than 500 ns delay. At discrete time intervals, the state of the
qubit is measured and corrected in case an error is detected. For Rabi
oscillations, where the discrete measurements occur when the qubit is supposed
to be in the measurement pointer states, we demonstrate an average fidelity of
85% to the targeted trajectory. For Ramsey oscillations, which does not go
through pointer states, the average fidelity reaches 75%. Incidentally, we
demonstrate a fast reset protocol allowing to cool a 3D transmon qubit down to
0.6% in the excited state.


title: Coincidental pattern avoidance

abstract:
  There are several versions of permutation pattern avoidance that have arisen
in the literature, and some known examples of two different types of pattern
avoidance coinciding. In this paper, we examine barred patterns and vincular
patterns. Answering a question of Steingrimsson, we determine when barred
pattern avoidance coincides with avoiding a finite set of vincular patterns,
and when vincular pattern avoidance coincides with avoiding a finite set of
barred patterns. There are 720 barred patterns with this property, each having
between 3 and 7 letters, of which at most 2 are barred, and there are 48
vincular patterns with this property, each having between 2 and 4 letters and
exactly one bond.


title: Study of Neutron-Capture Element Abundances in Metal-Poor Stars

abstract:
  This work describes a study of elemental abundances for 30 metal-poor stars
whose chemical abundances provide excellent information for setting constraints
on models of neutron-capture processes. Based on the abundances of main r- and
weak r-process stars, the abundance patterns of main r-process and weak
r-process are obtained. The two r-process component coefficients are defined to
determine the relative contributions from individual neutron-capture process to
abundances of metal-poor stars. Based on the component coefficients, we find
that metal-poor stars BD+4 2621 and HD 4306 are also weak r-process stars,
which means that the abundance pattern produced by weak r-process is stable.
All metal-poor star abundances contain the contributions of both main r-process
and weak r-process. The elements produced by weak r-process have increased
along with Fe over the polluted history. Most of the metal-poor star abundances
do not follow the pattern observed in solar system, but there is a small
fraction that do. For the low-[Sr/Fe] star BD-18 5550 ([Sr/Fe]$\lesssim-1$),
neutron-capture element abundances can be explained by the mixture of two
r-process components. Since lighter elements in this star cannot be fitted by
the two components, the abundance pattern of P-component is estimated from
those abundances.


title:
Dynamics of a superconducting qubit coupled to the quantized cavity
  field: a unitary transformation approach

abstract:
  We present a novel approach for studying the dynamics of a superconducting
qubit in a cavity. We succeed in linearizing the Hamiltonian through the
application of an appropriate unitary transformation followed by a rotating
wave approximation (RWA). For certain values of the parameters involved, we
show that it is possible to obtain a a Jaynes-Cummings type Hamiltonian. As an
example, we show the existence of super-revivals for the qubit inversion.


title:
CG-content log-ratio distributions of Caenorhabditis elegans and
  Drosophila melanogaster mirtrons

abstract:
  Mirtrons are a special type of pre-miRNA which originate from intronic
regions and are spliced directly from the transcript instead of being processed
by Drosha. The splicing mechanism is better understood for the processing of
mRNA for which was established that there is a characteristic CG content around
splice sites. Here we analyse the CG-content ratio of pre-miRNAs and mirtrons
and compare them with their genomic neighbourhood in an attempt to establish
key properties which are easy to evaluate and to understand their biogenesis.
We propose a simple log-ratio of the CG-content comparing the precursor
sequence and is flanking region. We discovered that Caenorhabditis elegans and
Drosophila melanogaster mirtrons, so far without exception, have smaller
CG-content than their genomic neighbourhood. This is markedly different from
usual pre-miRNAs which mostly have larger CG-content when compared to their
genomic neighbourhood. We also analysed some mammalian and primate mirtrons
which, in contrast the invertebrate mirtrons, have higher CG-content ratio.


title:
A Two-stage injection-locked magnetron for accelerators with
  superconducting cavities

abstract:
  A concept for a two-stage injection-locked CW magnetron intended to drive
Superconducting Cavities (SC) for intensity-frontier accelerators has been
proposed. The concept considers two magnetrons in which the output power
differs by 15-20 dB and the lower power magnetron being frequency-locked from
an external source locks the higher power magnetron. The injection-locked
two-stage CW magnetron can be used as an RF power source for Fermilab's
Project-X to feed separately each of the 1.3 GHz SC of the 8 GeV pulsed linac.
We expect output/locking power ratio of about 30-40 dB assuming operation in a
pulsed mode with pulse duration of ~ 8 ms and repetition rate of 10 Hz. The
experimental setup of a two-stage magnetron utilising CW, S-band, 1 kW tubes
operating at pulse duration of 1-10 ms, and the obtained results are presented
and discussed in this paper.


title:
A unified quantum theory II: gravity interacting with Yang-Mills and
  spinor fields

abstract:
  We quantize the interaction of gravity with Yang-Mills and spinor fields,
hence offering a quantum theory incorporating all four fundamental forces of
nature. Using canonical quantization we obtain solutions of the Wheeler-DeWitt
equation in a vector bundle and the method of second quantization leads to a
symplectic vector space $(V,\om)$ and a corresponding CCR representation for
the bosonic components and a CAR representation for the fermionic part. The
solution space of the Wheeler-DeWitt equation is invariant under gauge
transformations and under isometries in the spacelike base space $\so$ of a
given Riemannian metric $\rho_{ij}$. We also define a net of local subalgebras
which satisfy four of the Haag-Kastler axioms.


title: Medium-Induced QCD Cascade: Democratic Branching and Wave Turbulence

abstract:
  We study the average properties of the gluon cascade generated by an
energetic parton propagating through a quark-gluon plasma. We focus on the
soft, medium-induced emissions which control the energy transport at large
angles with respect to the leading parton. We show that the effect of multiple
branchings is important. In contrast with what happens in a usual QCD cascade
in vacuum, medium-induced branchings are quasidemocratic, with offspring gluons
carrying sizable fractions of the energy of their parent gluon. This results in
an efficient mechanism for the transport of energy toward the medium, which is
akin to wave turbulence with a scaling spectrum $\sim 1/\sqrt{\omega}$. We
argue that the turbulent flow may be responsible for the excess energy carried
by very soft quanta, as revealed by the analysis of the dijet asymmetry
observed in Pb-Pb collisions at the LHC.


title: Generation of rectangular optical waves by relativistic clipping

abstract:
  Theoretical results are reported, concerning the reflection and transmission
of few-cycle laser pulses on a very thin conducting layer, which may represent
the surface current density of the massless charges of graphene. It is shown
that the pulse may undergo violent distortions, even at moderate intensities,
to that extent, that the scattered radiation contains rectangular trains, which
are approximate realizations of Rademacher functions in the optical or
terahertz regime.


title: The Qth-power algorithm in characteristic 0

abstract:
  The Qth-power algorithm produces a useful canonical P-module presentation for
the integral closures of certain integral extensions of
$P:=\mathbf{F}[x_n,...,x_1]$, a polyonomial ring over the finite field
$\mathbf{F}:=\mathbf{Z}_q$ of $q$ elements. Here it is shown how to use this
for several small primes $q$ to reconstruct similar integral closures over the
rationals $\mathbf{Q}$ using the Chinese remainder theorem to piece together
presentations in different positive characteristics, and the extended Euclidean
algorithm to reconstruct rational fractions to lift these to presentations over
$\mathbf{Q}$.


title:
CMB and matter power spectra from cross correlations of primordial
  curvature and magnetic fields

abstract:
  A complete numerical calculation of the temperature anisotropies and the
polarization of the cosmic microwave background (CMB) is presented for a non
zero cross correlation of a stochastic magnetic field with the primordial
curvature perturbation. Such a cross correlation results, for example, if the
magnetic field is generated during inflation by coupling electrodynamics to a
scalar field which is identified with the curvaton. For a nearly scale
invariant magnetic field of 1 nG it is found that at low multipoles the
contribution due to the cross correlation dominates over that of the pure
magnetic mode. A similar behaviour on large scales is found for the linear
matter power spectrum.


title:
All-Heusler giant-magnetoresistance junctions with matched energy bands
  and Fermi surfaces

abstract:
  We present an all-Heusler architecture which could be used as a rational
design scheme for achieving high spin-filtering efficiency in the
current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices. A
Co2MnSi/Ni2NiSi/Co2MnSi trilayer stack is chosen as the prototype of such an
architecture, of which the electronic structure and magnetotransport properties
are systematically investigated by first principles approaches. Almost
perfectly matched energy bands and Fermi surfaces between the all-Heusler
electrode-spacer pair are found, indicating large interfacial spin-asymmetry,
high spin-injection efficiency, and consequently high GMR ratio. Transport
calculations further confirms the superiority of the all-Heusler architecture
over the conventional Heusler/transition-metal(TM) structure by comparing their
transmission coefficients and interfacial resistances of parallel conduction
electrons, as well as the macroscopic current-voltage (I-V) characteristics. We
suggest future theoretical and experimental efforts in developing novel
all-Heusler GMR junctions for the read heads of the next generation
high-density hard disk drives (HDDs).


title:
On the correction of anomalous phase oscillation in entanglement
  witnesses using quantum neural networks

abstract:
  Entanglement of a quantum system depends upon relative phase in complicated
ways, which no single measurement can reflect. Because of this, entanglement
witnesses are necessarily limited in applicability and/or utility. We propose
here a solution to the problem using quantum neural networks. A quantum system
contains the information of its entanglement; thus, if we are clever, we can
extract that information efficiently. As proof of concept, we show how this can
be done for the case of pure states of a two-qubit system, using an
entanglement indicator corrected for the anomalous phase oscillation. Both the
entanglement indicator and the phase correction are calculated by the quantum
system itself acting as a neural network.


title: Observation of suppressed terahertz absorption in photoexcited graphene

abstract:
  When light is absorbed by a semiconductor, photoexcited charge carriers
enhance the absorption of far-infrared radiation due to intraband transitions.
We observe the opposite behavior in monolayer graphene, a zero-gap
semiconductor with linear dispersion. By using time domain terahertz (THz)
spectroscopy in conjunction with optical pump excitation, we observe a reduced
absorption of THz radiation in photoexcited graphene. The measured spectral
shape of the differential optical conductivity exhibits non-Drude behavior. We
discuss several possible mechanisms that contribute to the observed
low-frequency non-equilibrium optical response of graphene.


title:
Properties of defect modes in periodic lossy multilayer with negative
  index materials

abstract:
  Transmission properties of one-dimensional lossy photonic crystals composed
of negative and positive refractive index layers with one lossless defect layer
at the center of the crystal are investigated by the characteristic matrix
method. The results show that as the refractive index and thickness of the
defect layer increase the frequency of the defect mode decreases. In addition,
it is shown that the frequency of the defect mode is sensitive to the incidence
angle, polarization and physical properties of the defect layer but it is
insensitive to the small lattice loss factor. The height of the defect mode is
very sensitive to the loss factor, incidence angle, polarization, refractive
index and thickness of the defect layer. It was also shown that the height and
the width of the defect mode are affected by the number of the lattice period
and the loss factor. The results can lead to designing new types of narrow
filter structures and other optical devices.


title:
N-body simulations of oligarchic growth of Mars: Implications for Hf-W
  chronology

abstract:
  Dauphas and Pourmand (2011) [Nature 473, 489--492] estimated the accretion
timescale of Mars to be 1.8 $^{+0.9}_{-1.0}$ Myr from the W isotopes of martian
meteorites. This timescale was derived assuming perfect metal-silicate
equilibration between the impactor and the target's mantle. However, in the
case of a small impactor most likely only a fraction of the target's mantle is
involved in the equilibration, while only a small part of the impactor's core
equilibrates in the case of a giant impact. We examined the effects of
imperfect equilibration using results of high-resolution $N$-body simulations
for the oligarchic growth stage. These effects were found to be small as long
as a planetary embryo has a deep liquid magma ocean during its accretion. The
effect due to partial involvement of the target's mantle in equilibration is
small due to the low metal-silicate partition coefficient for W suggested from
the low Hf/W ratio of the martian mantle. The effect due to partial involvement
of the impactor's core is also small because a large fraction of the embryo
mass is delivered from small planetesimals, which are likely to fully
equilibrate in the deep magma ocean on the embryo. The accretion timescale of
Mars estimated by the Hf-W chronology is shorter than that expected for the
minimum mass solar nebula model as long as more than 10% of each impactor's
core re-equilibrates with the martian mantle and the final stages of accretion
are prolonged. This probably indicates that accretion of Mars proceeded rapidly
due to solid and gas surface densities significantly larger than those for the
minimum mass solar nebula or due to accretion of small fragments or pebbles.


title:
A Proof of Threshold Saturation for Spatially-Coupled LDPC Codes on BMS
  Channels

abstract:
  Low-density parity-check (LDPC) convolutional codes have been shown to
exhibit excellent performance under low-complexity belief-propagation decoding
[1], [2]. This phenomenon is now termed threshold saturation via spatial
coupling. The underlying principle behind this appears to be very general and
spatially-coupled (SC) codes have been successfully applied in numerous areas.
Recently, SC regular LDPC codes have been proven to achieve capacity
universally, over the class of binary memoryless symmetric (BMS) channels,
under belief-propagation decoding [3], [4].
  In [5], [6], potential functions are used to prove that the BP threshold of
SC irregular LDPC ensembles saturates, for the binary erasure channel, to the
conjectured MAP threshold (known as the Maxwell threshold) of the underlying
irregular ensembles. In this paper, that proof technique is generalized to BMS
channels, thereby extending some results of [4] to irregular LDPC ensembles. We
also believe that this approach can be expanded to cover a wide class of
graphical models whose message-passing rules are associated with a Bethe free
energy.


title:
A Robbins-Monro type algorithm for computing global minimizer of
  generalized conic functions

abstract:
  We generalize the notion and some properties of the conic function introduced
by Vincze and Nagy (2012). We provide a stochastic algorithm for computing the
global minimizer of generalized conic functions, we prove almost sure and
L^q-convergence of this algorithm.


title: Research Proposal for an Experiment to Search for the Decay {\mu} -> eee

abstract:
  We propose an experiment (Mu3e) to search for the lepton flavour violating
decay mu+ -> e+e-e+. We aim for an ultimate sensitivity of one in 10^16
mu-decays, four orders of magnitude better than previous searches. This
sensitivity is made possible by exploiting modern silicon pixel detectors
providing high spatial resolution and hodoscopes using scintillating fibres and
tiles providing precise timing information at high particle rates.


title:
Leverage-induced systemic risk under Basle II and other credit risk
  policies

abstract:
  We use a simple agent based model of value investors in financial markets to
test three credit regulation policies. The first is the unregulated case, which
only imposes limits on maximum leverage. The second is Basle II and the third
is a hypothetical alternative in which banks perfectly hedge all of their
leverage-induced risk with options. When compared to the unregulated case both
Basle II and the perfect hedge policy reduce the risk of default when leverage
is low but increase it when leverage is high. This is because both regulation
policies increase the amount of synchronized buying and selling needed to
achieve deleveraging, which can destabilize the market. None of these policies
are optimal for everyone: Risk neutral investors prefer the unregulated case
with low maximum leverage, banks prefer the perfect hedge policy, and fund
managers prefer the unregulated case with high maximum leverage. No one prefers
Basle II.


title: DebtRank-transparency: Controlling systemic risk in financial networks

abstract:
  Banks in the interbank network can not assess the true risks associated with
lending to other banks in the network, unless they have full information on the
riskiness of all the other banks. These risks can be estimated by using network
metrics (for example DebtRank) of the interbank liability network which is
available to Central Banks. With a simple agent based model we show that by
increasing transparency by making the DebtRank of individual nodes (banks)
visible to all nodes, and by imposing a simple incentive scheme, that reduces
interbank borrowing from systemically risky nodes, the systemic risk in the
financial network can be drastically reduced. This incentive scheme is an
effective regulation mechanism, that does not reduce the efficiency of the
financial network, but fosters a more homogeneous distribution of risk within
the system in a self-organized critical way. We show that the reduction of
systemic risk is to a large extent due to the massive reduction of cascading
failures in the transparent system. An implementation of this minimal
regulation scheme in real financial networks should be feasible from a
technical point of view.


title: Line of critical states for Lennard-Jones fluids

abstract:
  A method of obtaining the critical temperature from within a supercritical
mesophase bounded by percolation transition loci is described. We report
thermodynamic pressures from MD simulations for more than 2000 state points
along 7 near-critical isotherms of a Lennard-Jones fluid. Direct evaluation of
Gibbs chemical potential along the critical isotherm reaffirms the existence of
a supercritical mesophaseand a line of critical states and non-existence of van
der Waals critical point.


title: Higher genus universally decodable matrices (UDMG)

abstract:
  We introduce the notion of Universally Decodable Matrices of Genus g (UDMG),
which for g=0 reduces to the notion of Universally Decodable Matrices (UDM)
introduced in [8]. A UDMG is a set of L matrices over a finite field, each with
K rows, and a linear independence condition satisfied by collections of K+g
columns formed from the initial segments of the matrices. We consider the
mathematical structure of UDMGs and their relation to linear vector codes. We
then give a construction of UDMG based on curves of genus g over the finite
field, which is a natural generalization of the UDM constructed in [8]. We
provide upper (and constructable lower) bounds for L in terms of K, q, g, and
the number of columns of the matrices. We will show there is a fundamental
trade off (Theorem 5.4) between L and g, akin to the Singleton bound for the
minimal Hamming distance of linear vector codes.


title: X THEN X: Manipulation of Same-System Runoff Elections

abstract:
  Do runoff elections, using the same voting rule as the initial election but
just on the winning candidates, increase or decrease the complexity of
manipulation? Does allowing revoting in the runoff increase or decrease the
complexity relative to just having a runoff without revoting? For both weighted
and unweighted voting, we show that even for election systems with simple
winner problems the complexity of manipulation, manipulation with runoffs, and
manipulation with revoting runoffs are independent, in the abstract. On the
other hand, for some important, well-known election systems we determine what
holds for each of these cases. For no such systems do we find runoffs lowering
complexity, and for some we find that runoffs raise complexity. Ours is the
first paper to show that for natural, unweighted election systems, runoffs can
increase the manipulation complexity.


title:
Velocity and Vorticity Measurements of Jupiter's Great Red Spot Using
  Automated Cloud Feature Tracking

abstract:
  We have produced mosaics of the Great Red Spot (GRS) using images taken by
the Galileo spacecraft in May 2000, and have measured the winds of the GRS
using an automated algorithm that does not require manual cloud tracking. Our
technique yields a high-density, regular grid of wind velocity vectors that is
advantageous over a limited number of scattered wind vectors that result from
manual cloud tracking. The high-velocity collar of the GRS is clearly seen from
our velocity vector map, and highest wind velocities are measured to be around
170 m/s. The high resolution of the mosaics have also enabled us to map
turbulent eddies inside the chaotic central region of the GRS, similar to those
mapped by Sada et al. (1996) and Vasavada et al. (1998). Using the wind
velocity measurements, we computed particle trajectories around the GRS as well
as maps of relative and absolute vorticities. We have discovered a narrow ring
of cyclonic vorticity that surrounds the main anti-cyclonic high-velocity
collar. This narrow ring appears to correspond to a ring surrounding the GRS
that is bright in 5-microns (Terrile and Beebe 1979). It appears that this
cyclonic ring is not a transient feature of the GRS, as we have discovered it
in a re-analysis of Galileo data taken in 1996 first analyzed by Vasavada et
al. (1998). We also calculate how absolute vorticity changes as a function of
latitude along a trajectory around the GRS and compare these measurements to
similar ones performed by Dowling and Ingersoll (1988) using Voyager data. We
show no dramatic evolution in the structure of the GRS since the Voyager era
except for additional evidence for a counterrotating GRS core, an increase in
velocity in the main velocity collar, and an overall decrease in the length of
the GRS.


title:
A Rate-Splitting Approach to Fading Channels with Imperfect
  Channel-State Information

abstract:
  As shown by M\'edard, the capacity of fading channels with imperfect
channel-state information (CSI) can be lower-bounded by assuming a Gaussian
channel input $X$ with power $P$ and by upper-bounding the conditional entropy
$h(X|Y,\hat{H})$ by the entropy of a Gaussian random variable with variance
equal to the linear minimum mean-square error in estimating $X$ from
$(Y,\hat{H})$. We demonstrate that, using a rate-splitting approach, this lower
bound can be sharpened: by expressing the Gaussian input $X$ as the sum of two
independent Gaussian variables $X_1$ and $X_2$ and by applying M\'edard's lower
bound first to bound the mutual information between $X_1$ and $Y$ while
treating $X_2$ as noise, and by applying it a second time to the mutual
information between $X_2$ and $Y$ while assuming $X_1$ to be known, we obtain a
capacity lower bound that is strictly larger than M\'edard's lower bound. We
then generalize this approach to an arbitrary number $L$ of layers, where $X$
is expressed as the sum of $L$ independent Gaussian random variables of
respective variances $P_{\ell}$, $\ell = 1,\dotsc,L$ summing up to $P$. Among
all such rate-splitting bounds, we determine the supremum over power
allocations $P_\ell$ and total number of layers $L$. This supremum is achieved
for $L\to\infty$ and gives rise to an analytically expressible capacity lower
bound. For Gaussian fading, this novel bound is shown to converge to the
Gaussian-input mutual information as the signal-to-noise ratio (SNR) grows,
provided that the variance of the channel estimation error $H-\hat{H}$ tends to
zero as the SNR tends to infinity.


title: On the Volume of Isolated Singularities

abstract:
  We give an equivalent definition of the local volume of an isolated
singularity Vol_{BdFF}(X,0) given in [BdFF12] in the Q-Gorenstein case and we
generalize it to the non-Q-Gorenstein case. We prove that there is a positive
lower bound depending only on the dimension for the non-zero local volume of an
isolated singularity if X is Gorenstein. We also give a non-Q-Gorenstein
example with Vol_{BdFF}(X,0)=0, which does not allow a boundary \Delta such
that the pair (X,\Delta) is log canonical.


title:
Search for the standard model Higgs boson in $\bm{\ell\nu}$+jets final
  states in 9.7~fb$\bm{^{-1}}$ of $\bm{p\bar{p}}$ collisions with the D0
  detector

abstract:
  We present, in detail, a search for the standard model Higgs boson, $H$, in
final states with a charged lepton (electron or muon), missing energy, and two
or more jets in data corresponding to 9.7 fb$^{-1}$ of integrated luminosity
collected at a center of mass energy of $\sqrt{s}$ = 1.96 TeV with the D0
detector at the Fermilab Tevatron $p\bar{p}$ Collider. The search uses $b$-jet
identification to categorize events for improved signal versus background
separation and is sensitive to associated production of the $H$ with a $W$
boson, $WH\to\ell\nu b\bar{b}$; gluon fusion with the Higgs decaying to $W$
boson pairs, $H\to WW\to\ell\nu jj$; and associated production with a vector
boson where the Higgs decays to $W$ boson pairs, $VH\to VWW \to \ell\nu jjjj$
production (where $V = W$ or $Z$). We observe good agreement between data and
expected background. We test our method by measuring $WZ$ and $ZZ$ production
with $Z\to b\bar{b}$ and find production rates consistent with the standard
model prediction. For a Higgs boson mass of 125 GeV, we set a 95%\ C.L. upper
limit on the production of a standard model Higgs boson of
\obslimA$\times\sigma_{\rm SM}$, where $\sigma_{\rm SM}$ is the standard model
Higgs boson production cross section, while the expected limit is
\explimA$\times\sigma_{\rm SM}$. We also interpret the data considering models
with fourth generation fermions, or a fermiophobic Higgs boson.


title: Classifying Several Classes of Leibniz Algebras

abstract:
  We extend results related to maximal subalgebras and ideals from Lie to
Leibniz algebras. In particular, we classify minimal non-elementary Leibniz
algebras and Leibniz algebras with a unique maximal ideal. In both cases, there
are types of these algebras with no Lie algebra analogue. We also give a
classification of E-Leibniz algebras which is very similiar to its Lie algebra
counterpart.


title:
Cloud Features and Zonal Wind Measurements of Saturn's Atmosphere as
  Observed by Cassini/VIMS

abstract:
  We present an analysis of data about Saturn's atmosphere from Cassini's
Visual and Infrared Mapping Spectrometer (VIMS), focusing on the meteorology of
the features seen in the 5-micron spectral window. We present VIMS mosaics and
discuss the morphology and general characteristics of the features backlit by
Saturn's thermal emission. We have also constructed a zonal wind profile from
VIMS feature tracking observation sequences using an automated cloud feature
tracker. Comparison with previously constructed profiles from Voyager and
Cassini imaging data reveals broad similarities, suggesting minimal vertical
shear of the zonal wind. However, areas of apparent wind shear are present in
the VIMS zonal wind profile at jet stream cores. In particular, our analysis
shows that the equatorial jet reaches speeds exceeding 450 m/s, similar to
speeds obtained during the Voyager era. This suggests that recent inferences of
relatively slower jet speeds of ~275-375 m/s are confined to the upper
troposphere and that the deep (>1 bar) jet has not experienced a significant
slowdown. Our measurements of the numerous dark, spotted features seen in the
VIMS mosaics reveals that most of these features have diameters less than 1000
km and reside in confined zonal bands between jet stream cores. We propose that
these spot features are vortices and that VIMS and ISS are sensing the same
vortices at two different pressure levels. The local structure at the zonal jet
streams remains complex, as VIMS may be sensing cloud features that are deeper
than the NH3 cloud deck.


title: Flaglets: Exact Wavelets on the Ball

abstract:
  We summarise the construction of exact axisymmetric scale-discretised
wavelets on the sphere and on the ball. The wavelet transform on the ball
relies on a novel 3D harmonic transform called the Fourier-Laguerre transform
which combines the spherical harmonic transform with damped Laguerre
polynomials on the radial half-line. The resulting wavelets, called flaglets,
extract scale-dependent, spatially localised features in three-dimensions while
treating the tangential and radial structures separately. Both the
Fourier-Laguerre and the flaglet transforms are theoretically exact thanks to a
novel sampling theorem on the ball. Our implementation of these methods is
publicly available and achieves floating-point accuracy when applied to
band-limited signals.


title: The Evolving Flow of Jupiter's White Ovals and Adjacent Cyclones

abstract:
  We present results regarding the dynamical meteorology of Jupiter's White
Ovals at different points in their evolution. Starting from the era with three
White Ovals FA, BC, and DE (Galileo), continuing to the post-merger epoch with
only one Oval BA (Cassini), and finally to Oval BA's current reddened state
(New Horizons), we demonstrate that the dynamics of their flow have similarly
evolved along with their appearance. The northern periphery of Oval BA
increased in speed by 20 m/s from Cassini to New Horizons, ending up at a speed
nearly identical to that of the northern periphery of Oval DE during Galileo.
However, the peak speeds along the southern rim of the newly formed Oval BA
were consistently faster than the corresponding speeds in Oval DE, and they
increased still further between Cassini and New Horizons, ending up at ~140 to
150 m/s. The modest strengthening of the winds in Oval BA, the appearance of
red aerosols, and the appearance of a turbulent, cyclonic feature to Oval BA's
northwest create a strong resemblance with the Great Red Spot from both a
dynamical and morphological perspective. In addition to the White Ovals, we
also measure the winds within two compact cyclonic regions, one in the Galileo
data set and one in the Cassini data set. In the images, these cyclonic
features appear turbulent and filamentary, but our wind field reveals that the
flow manifests as a coherent high-speed collar surrounding relatively quiescent
interiors. Although less studied than their anticyclonic cousins, these
cyclones may offer crucial insights into the planet's cloud-level energetics
and dynamical meteorology.


title: Binary Jumbled Pattern Matching on Trees and Tree-Like Structures

abstract:
  Binary jumbled pattern matching asks to preprocess a binary string $S$ in
order to answer queries $(i,j)$ which ask for a substring of $S$ that is of
length $i$ and has exactly $j$ 1-bits. This problem naturally generalizes to
vertex-labeled trees and graphs by replacing "substring" with "connected
subgraph". In this paper, we give an $O(n^2 / \log^2 n)$-time solution for
trees, matching the currently best bound for (the simpler problem of) strings.
We also give an $\Oh{g^{2 / 3} n^{4 / 3}/(\log n)^{4/3}}$-time solution for
strings that are compressed by a grammar of size $g$. This solution improves
the known bounds when the string is compressible under many popular compression
schemes. Finally, we prove that the problem is fixed-parameter tractable with
respect to the treewidth $w$ of the graph, thus improving the previous best
$n^{O(w)}$ algorithm [ICALP'07].


title: Fluctuating charge density waves in a cuprate superconductor

abstract:
  Cuprate materials hosting high-temperature superconductivity (HTS) also
exhibit various forms of charge and/or spin ordering whose significance is not
fully understood. To date, static charge-density waves (CDWs) have been
detected by diffraction probes only at special doping or in an applied external
field. However, dynamic CDWs may also be present more broadly and their
detection, characterization and relationship with HTS remain open problems.
Here, we present a new method, based on ultrafast spectroscopy, to detect the
presence and measure the lifetimes of CDW fluctuations in cuprates. In an
underdoped La1.9Sr0.1CuO4 film (Tc = 26 K), we observe collective excitations
of CDW that persist up to 100 K. This dynamic CDW fluctuates with a
characteristic lifetime of 2 ps at T = 5 K which decreases to 0.5 ps at T = 100
K. In contrast, in an optimally doped La1.84Sr0.16CuO4 film (Tc = 38.5 K), we
detect no signatures of fluctuating CDWs at any temperature, favoring the
competition scenario. This work forges a path for studying fluctuating order
parameters in various superconductors and other materials.


title:
Character Formulas on Cohomology of Deformations of Hilbert Schemes of
  K3 Surfaces

abstract:
  Let X be a hyperkahler manifold deformation equivalent to a Hilbert scheme
of n points on a K3 surface. We compute the graded character formula of the
generic Mumford-Tate group representation on the cohomology ring of X, and
derive a generating series for deducing the number of canonical Hodge classes
on X. The formula indicates the number of Hodge classes on X that remain Hodge
under any deformation.


title: Measurements of Martian Dust Devil Winds with HiRISE

abstract:
  We report wind measurements within Martian dust devils observed in plan view
from the High Resolution Imaging Science Experiment (HiRISE) orbiting Mars. The
central color swath of the HiRISE instrument has three separate charge-coupled
devices (CCDs) and color filters that observe the surface in rapid cadence.
Active features, such as dust devils, appear in motion when observed by this
region of the instrument. Our image animations reveal clear circulatory motion
within dust devils that is separate from their translational motion across the
Martian surface. Both manual and automated tracking of dust devil clouds reveal
tangential winds that approach 20-30 m/s in some cases. These winds are
sufficient to induce a ~1% decrease in atmospheric pressure within the dust
devil core relative to ambient, facilitating dust lifting by reducing the
threshold wind speed for particle elevation. Finally, radial velocity profiles
constructed from our automated measurements test the Rankine vortex model for
dust devil structure. Our profiles successfully reveal the solid body rotation
component in the interior, but fail to conclusively illuminate the profile in
the outer regions of the vortex. One profile provides evidence for a velocity
decrease as a function of r^-1/2, instead of r^-1, suggestive of surface
friction effects. However, other profiles do not support this observation, or
do not contain enough measurements to produce meaningful insights.


title:
Refractive index changes of multi-layered spherical nanostructures with
  donor impurity

abstract:
  In this study, the linear, third-order nonlinear and total refractive index
(RI) changes of multi-layered quantum dot (MLQD) and multi-layered quantum
anti-dot (MLQAD) with a hydrogenic impurity are calculated. Our numerical
results indicate that the RI changes are considerably sensitive to the
geometrical parameters of systems and the incident optical intensity. It is
observed that by changing the incident photon energy, the RI curves
corresponding to MLQAD and MLQD are considerably different in shapes and
behaviors. Generally, our results show that MLQAD models have very higher RIs
than MLQD models.


title:
Power Spectral Analysis of Jupiter's Clouds and Kinetic Energy from
  Cassini

abstract:
  We present suggestive evidence for an inverse energy cascade within Jupiter's
atmosphere through a calculation of the power spectrum of its kinetic energy
and its cloud patterns. Using Cassini observations, we composed
full-longitudinal mosaics of Jupiter's atmosphere at several wavelengths. We
also utilized image pairs derived from these observations to generate
full-longitudinal maps of wind vectors and atmospheric kinetic energy within
Jupiter's troposphere. We computed power spectra of the image mosaics and
kinetic energy maps using spherical harmonic analysis. Power spectra of
Jupiter's cloud patterns imaged at certain wavelengths resemble theoretical
spectra of two-dimensional turbulence, with power-law slopes near -5/3 and -3
at low and high wavenumbers, respectively. The slopes of the kinetic energy
power spectrum are also near -5/3 at low wavenumbers. At high wavenumbers,
however, the spectral slopes are relatively flatter than the theoretical
prediction of -3. Our results also show the importance of calculating spectral
slopes from full 2D velocity maps rather than 1D zonal mean velocity profiles,
since at large wavenumbers the spectra differ significantly, though at low
wavenumbers, the 1D zonal and full 2D kinetic energy spectra are practically
indistinguishable. Furthermore, the difference between the image and kinetic
energy spectra suggests some caution in the interpretation of power spectrum
results solely from image mosaics and its significance for the underlying
dynamics. Finally, we also report prominent variations in kinetic energy within
the equatorial jet stream that appear to be associated with the 5 {\mu}m
hotspots. Other eddies are present within the flow collar of the Great Red
Spot, suggesting caution when interpreting snapshots of the flow inside these
features as representative of a time-averaged state.


title: Effects of the Generalized Uncertainty Principle on Compact Stars

abstract:
  Based on the generalized uncertainty principle (GUP), proposed by some
approaches to quantum gravity such as string theory and doubly special
relativity theories, we investigate the effect of GUP on the thermodynamic
properties of compact stars with two different components. We note that the
existence of quantum gravity correction tends to resist the collapse of stars
if the GUP parameter $\alpha$ is taking values between Planck scale and
electroweak scale. Comparing with approaches, it is found that the radii of
compact stars are found smaller. Increasing energy almost exponentially
decreases the radii of compact stars.


title:
The two-nucleon problem in EFT reformulated: Pion and nucleon masses as
  soft and hard scales

abstract:
  We outline the modified formulation of baryon chiral effective field theory
for nucleon-nucleon scattering and discuss the issue of a possible power
counting violation by the nucleon mass. We also present the results for the
quark mass dependence of the $^1S_0$ and $^3S_1$ scattering lengths and the
deuteron binding energy at leading order.


title: Scalar Curvature for Noncommutative Four-Tori

abstract:
  In this paper we study the curved geometry of noncommutative 4-tori
$\mathbb{T}_\theta^4$. We use a Weyl conformal factor to perturb the standard
volume form and obtain the Laplacian that encodes the local geometric
information. We use Connes' pseudodifferential calculus to explicitly compute
the terms in the small time heat kernel expansion of the perturbed Laplacian
which correspond to the volume and scalar curvature of $\mathbb{T}_\theta^4$.
We establish the analogue of Weyl's law, define a noncommutative residue, prove
the analogue of Connes' trace theorem, and find explicit formulas for the local
functions that describe the scalar curvature of $\mathbb{T}_\theta^4$. We also
study the analogue of the Einstein-Hilbert action for these spaces and show
that metrics with constant scalar curvature are critical for this action.


title: A Possible Cold Imprint of Voids on the Microwave Background Radiation

abstract:
  We measure the average temperature decrement on the cosmic microwave
background (CMB) produced by voids selected in the SDSS DR7 spectroscopic
redshift galaxy catalog, spanning redshifts $0<z<0.44$. We find an imprint of
amplitude between 2.6 and 2.9$\mu K$ as viewed through a compensated top-hat
filter scaled to the radius of each void; we assess the statistical
significance of the imprint at ~2$\sigma$. We make crucial use of $N$-body
simulations to calibrate our analysis. As expected, we find that large voids
produce cold spots on the CMB through the Integrated Sachs-Wolfe (ISW) effect.
However, we also find that small voids in the halo density field produce hot
spots, because they reside in contracting, larger-scale overdense regions. This
is an important effect to consider when stacking CMB imprints from voids of
different radius. We have found that the same filter radius that gives the
largest ISW signal in simulations also yields close to the largest detected
signal in the observations. However, although it is low in significance, our
measured signal is much higher-amplitude than expected from ISW in the
concordance $\Lambda$CDM universe. The discrepancy is also at the ~2$\sigma$
level. We have demonstrated that our result is robust against the varying of
thresholds over a wide range.


title:
Nonlocal actin orientation models select for a unique orientation
  pattern

abstract:
  Many models have been developed to study the role of branching actin networks
in motility. One important component of those models is the distribution of
filament orientations relative to the cell membrane. Two mean-field models
previously proposed are generalized and analyzed. In particular, we find that
both models uniquely select for a dominant orientation pattern. In the linear
case, the pattern is the eigenfunction associated with the principal
eigenvalue. In the nonlinear case, we show there exists a unique equilibrium
and that the equilibrium is locally stable. Approximate techniques are then
used to provide evidence for global stability.


title: A Two-Phase Low-velocity Outflow in the Seyfert 1 Galaxy Ark~564

abstract:
  The Seyfert 1 galaxy Ark 564 was observed with Chandra high energy
transmission gratings for 250 ks. We present the high resolution X-ray spectrum
that shows several associated absorption lines. The photoionization model
requires two warm absorbers with two different ionization states
(logU=0.39\pm0.03 and logU=-0.99\pm0.13), both with moderate outflow velocities
(~100 km s^-1) and relatively low line of sight column densities (logNH=20.94
and 20.11 cm^-2). The high ionization phase produces absorption lines of OVII,
OVIII, NeIX, NeX, MgXI, FeXVII and FeXVIII while the low ionization phase
produces lines at lower energies (OVI & OVII). The pressure--temperature
equilibrium curve for the Ark 564 absorber does not have the typical "S" shape,
even if the metallicity is super-solar; as a result the two warm-absorber
phases do not appear to be in pressure balance. This suggests that the
continuum incident on the absorbing gas is perhaps different from the observed
continuum. We also estimated the mass outflow rate and the associated kinetic
energy and find it to be at most 0.006% of the bolometric luminosity of
Ark~564. Thus it is highly unlikely that these outflows provide significant
feedback required by the galaxy formation models.


title: Discovery of Relativistic Outflow in the Seyfert Galaxy Ark 564

abstract:
  We present \chandra high energy transmission grating spectra of the
narrow-line Seyfert-1 galaxy Ark 564. The spectrum shows numerous absorption
lines which are well modeled with low velocity outflow components usually
observed in Seyfert galaxies \citep{Gupta2013}. There are, however, some
residual absorption lines which are not accounted for by low-velocity outflows.
Here we present identifications of the strongest lines as $K\alpha$ transitions
of \oviin (two lines) and \ovin at outflow velocities of $\sim 0.1c$. These
lines are detected at $6.9\sigma$, $6.2\sigma$, and $4.7\sigma$ respectively
and cannot be due to chance statistical fluctuations. Photoionization models
with ultra-high velocity components improves the spectral fit significantly,
providing further support for the presence of relativistic outflow in this
source. Without knowing the location of the absorber, its mass and energy
outflow rates cannot be well constrained; we find $\dot{E}(outflow)/L_{bol}$
lower limit of $\geq 0.006$% assuming a bi-conical wind geometry. This is the
first time that absorption lines with ultra-high velocities are unambiguously
detected in the soft X-ray band. The presence of outflows with relativistic
velocities in AGNs with Seyfert-type luminosities is hard to understand and
provides valuable constraints to models of AGN outflows. Radiation pressure is
unlikely to be the driving mechanism for such outflows and magneto-hydrodynamic
may be involved.


title: Constraining f(R) theories with cosmography

abstract:
  A method to set constraints on the parameters of extended theories of
gravitation is presented. It is based on the comparison of two series
expansions of any observable that depends on H(z). The first expansion is of
the cosmographical type, while the second uses the dependence of H with z
furnished by a given type of extended theory. When applied to f(R) theories
together with the redshift drift, the method yields limits on the parameters of
two examples (the theory of Hu and Sawicki (2007), and the exponential gravity
introduced by Linder (2009)) that are compatible with or more stringent than
the existing ones, as well as a limit for a previously unconstrained parameter.


title: Modelling systemic price cojumps with Hawkes factor models

abstract:
  Instabilities in the price dynamics of a large number of financial assets are
a clear sign of systemic events. By investigating a set of 20 high cap stocks
traded at the Italian Stock Exchange, we find that there is a large number of
high frequency cojumps. We show that the dynamics of these jumps is described
neither by a multivariate Poisson nor by a multivariate Hawkes model. We
introduce a Hawkes one factor model which is able to capture simultaneously the
time clustering of jumps and the high synchronization of jumps across assets.


title:
Upper critical field of isoelectron substituted
  SrFe$_2$(As$_{1-x}$P$_x$)$_2$

abstract:
  The upper critical field $H_{c2}$ of optimally doped iron-based
superconductor SrFe$_{2}$(As$_{1-x}$P$_{x}$)$_{2}$ ($x$ = 0.35, $T_c$ = 25 K)
was measured as a function of temperature down to 1.6 K for two principal
directions of magnetic field $H \parallel c$ and $H \parallel a$. Measurements
were performed in pulsed magnetic fields up to 65 T using a tunnel-diode
resonator technique on as-grown and heavy-ion irradiated single crystals, with
columnar defect density corresponding to a matching field $B\phi$ = 25 T. The
$H_{c2,c}(T)$ is close to $T$-linear, while clear saturation is observed for
$H_{c2,a}(T)$, leading to a strongly temperature dependent anisotropy parameter
$\gamma$. The linear shape of $H_{c2,c}(T)$ is very similar to that observed in
nodal KFe$_2$As$_2$ but very different from full-gap LiFeAs. Irradiation does
not introduce any additional features on $H_{c2}(T)$ line corresponding to the
matching field. Instead, it suppresses uniformly both $T_c$ and $H_{c2}$,
keeping their ratio constant.


title:
A general approach to Read's type constructions of operators without
  non-trivial invariant closed subspaces

abstract:
  We present a general method for constructing operators without non-trivial
invariant closed subsets on a large class of non-reflexive Banach spaces. In
particular, our approach unifies and generalizes several constructions due to
Read of operators without non-trivial invariant subspaces on the spaces
$\ell_{1}$, $c_{0}$ or $\oplus_{\ell_{2}}J$, and without non-trivial invariant
subsets on $\ell_{1}$. We also investigate how far our methods can be extended
to the Hilbertian setting, and construct an operator on a quasireflexive dual
Banach space which has no non-trivial $w^{*}$-closed invariant subspace.


title:
An example of a minimal action of the free semi-group $\F^{+}_{2}$ on
  the Hilbert space

abstract:
  The Invariant Subset Problem on the Hilbert space is to know whether there
exists a bounded linear operator $T$ on a separable infinite-dimensional
Hilbert space $H$ such that the orbit $\{T^{n}x;\ n\ge 0\}$ of every non-zero
vector $x\in H$ under the action of $T$ is dense in $H$. We show that there
exists a bounded linear operator $T$ on a complex separable
infinite-dimensional Hilbert space $H$ and a unitary operator $V$ on $H$, such
that the following property holds true: for every non-zero vector $x\in H$,
either $x$ or $Vx$ has a dense orbit under the action of $T$. As a consequence,
we obtain in particular that there exists a minimal action of the free
semi-group with two generators $\F^{+}_{2}$ on a complex separable
infinite-dimensional Hilbert space $H$.


title:
Tests of local position invariance using continuously running atomic
  clocks

abstract:
  Tests of local position invariance (LPI) made by comparing the relative
redshift of atomic clocks based on different atoms have been carried out for a
variety of pairs of atomic species. In most cases, several absolute frequency
measurements per year are used to look for an annual signal, resulting in tests
that can span on order of a decade. By using the output of continuously running
clocks, we carry out LPI tests with comparable or higher precision after less
than 1.5 years. These include new measurements of the difference in redshift
anomalies \beta\ for hyperfine transitions in Rb87 and Cs133 and in H and Cs133
and a measurement comparing Rb87 and H, resulting in a stringent limit on LPI,
\beta(Rb) - \beta(H)=(-2.7 +/- 4.9) x 10^(-7). The method of making these
measurements for continuous clocks is discussed.


title:
Majorana fermions on the Abrikosov flux lattice in a $p_x+ip_y$
  superconductor and thermal conductivity in superclean regime

abstract:
  We show that periodic lattice of Abrikosov vortices in chiral $p$ wave
superconductor in general supports fermionic states with zero energy provided
the intervortex distance is smaller than the critical one. The zero modes
appear at the intersection with the Fermi level of electronic magnetic Bloch
bands formed by the overlapping vortex core states. The Bloch bands are robust
against lattice disorder induced by fluctuations of vortex positions and can
transmit the energy flow across the lattice. The hallmark of zero modes on
Bloch bands in electronic heat conductivity is discussed.


title: A Search for Exozodiacal Clouds with Kepler

abstract:
  Planets embedded within dust disks may drive the formation of large scale
clumpy dust structures by trapping dust into resonant orbits. Detection and
subsequent modeling of the dust structures would help constrain the mass and
orbit of the planet and the disk architecture, give clues to the history of the
planetary system, and provide a statistical estimate of disk asymmetry for
future exoEarth-imaging missions. Here we present the first search for these
resonant structures in the inner regions of planetary systems by analyzing the
light curves of hot Jupiter planetary candidates identified by the Kepler
mission. We detect only one candidate disk structure associated with KOI 838.01
at the 3-sigma confidence level, but subsequent radial velocity measurements
reveal that KOI 838.01 is a grazing eclipsing binary and the candidate disk
structure is a false positive. Using our null result, we place an upper limit
on the frequency of dense exozodi structures created by hot Jupiters. We find
that at the 90% confidence level, less than 21% of Kepler hot Jupiters create
resonant dust clumps that lead and trail the planet by ~90 degrees with optical
depths >~5*10^-6, which corresponds to the resonant structure expected for a
lone hot Jupiter perturbing a dynamically cold dust disk 50 times as dense as
the zodiacal cloud.


title:
Dirac Equation with vector and scalar potentials via Supersymmetry in
  Quantum Mechanics

abstract:
  In this work, a spin $\frac 12$ relativistic particle described by a
generalized potential containing both the Coulomb potential and a Lorentz
scalar potential in Dirac equation is investigated in terms of the generalized
ladder operators from supersymmetry in quantum mechanics.
  This formalism is applied for the generalized Dirac-Coulomb problem, which is
an exactly solvable potential in relativistic quantum mechanics. We obtain the
energy eigenvalues and calculate explicitly the energy eigenfunctions for the
ground state and the first excited state.


title:
Analysis of the Discontinuous Petrov-Galerkin Method with Optimal Test
  Functions for the Reissner-Mindlin Plate Bending Model

abstract:
  We analyze the discontinuous Petrov-Galerkin (DPG) method with optimal test
functions when applied to solve the Reissner-Mindlin model of plate bending. We
prove that the hybrid variational formulation underlying the DPG method is
well-posed (stable) with a thickness-dependent constant in a norm encompassing
the $L_2$-norms of the bending moment, the shear force, the transverse
deflection and the rotation vector. We then construct a numerical solution
scheme based on quadrilateral scalar and vector finite elements of degree $p$.
We show that for affine meshes the discretization inherits the stability of the
continuous formulation provided that the optimal test functions are
approximated by polynomials of degree $p+3$. We prove a theoretical error
estimate in terms of the mesh size $h$ and polynomial degree $p$ and
demonstrate numerical convergence on affine as well as non-affine mesh
sequences.


title: Polar Codes For Broadcast Channels

abstract:
  Polar codes are introduced for discrete memoryless broadcast channels. For
$m$-user deterministic broadcast channels, polarization is applied to map
uniformly random message bits from $m$ independent messages to one codeword
while satisfying broadcast constraints. The polarization-based codes achieve
rates on the boundary of the private-message capacity region. For two-user
noisy broadcast channels, polar implementations are presented for two
information-theoretic schemes: i) Cover's superposition codes; ii) Marton's
codes. Due to the structure of polarization, constraints on the auxiliary and
channel-input distributions are identified to ensure proper alignment of
polarization indices in the multi-user setting. The codes achieve rates on the
capacity boundary of a few classes of broadcast channels (e.g., binary-input
stochastically degraded). The complexity of encoding and decoding is $O(n*log
n)$ where $n$ is the block length. In addition, polar code sequences obtain a
stretched-exponential decay of $O(2^{-n^{\beta}})$ of the average block error
probability where $0 < \beta < 0.5$.


title:
Propagation of uncertainties in the Skyrme energy-density-functional
  model

abstract:
  Parameters of nuclear energy-density-functionals (EDFs) are always derived by
an optimization to experimental data. For the minima of appropriately defined
penalty functions, a statistical sensitivity analysis provides the
uncertainties of the EDF parameters. To quantify theoretical errors of
observables given by the model, we studied the propagation of uncertainties
within the UNEDF0 Skyrme-EDF approach. We found that typically the standard
errors rapidly increase towards neutron rich nuclei. This can be linked to
large uncertainties of the isovector coupling constants of the currently used
EDFs.


title: Nonseparable UHF algebras II: Classification

abstract:
  For every uncountable cardinal $\kappa$ there are $2^\kappa$ nonisomorphic
simple AF algebras of density character $\kappa$ and $2^\kappa$ nonisomorphic
hyperfinite II$_1$ factors of density character $\kappa$. These estimates are
maximal possible. All C*-algebras that we construct have the same Elliott
invariant and Cuntz semigroup as the CAR algebra.


title: Paradoxes of the Aharonov-Bohm and the Aharonov-Casher effects

abstract:
  For a believer in locality of Nature, the Aharonov-Bohm effect and the
Aharonov-Casher effect are paradoxes. I discuss these and other Aharonov's
paradoxes and propose a local explanation of these effects. If the solenoid in
the Aharonov-Bohm effect is treated quantum mechanically, the effect can be
explained via local interaction between the field of the electron and the
solenoid. I argue that the core of the Aharonov-Bohm and the Aharonov-Casher
effects is that of quantum entanglement: the quantum wave function describes
all systems together.


title: Peculiar Features of Entangled States with Post-Selection

abstract:
  We consider quantum systems in entangled states post-selected in
non-entangled states. Such systems exhibit unusual behavior, in particular when
weak measurements are performed at intermediate times.


title:
Collapse of the Cooper pair phase coherence length at a superconductor
  to insulator transition

abstract:
  We present investigations of the superconductor to insulator transition (SIT)
of uniform a-Bi films using a technique sensitive to Cooper pair phase
coherence. The films are perforated with a nanohoneycomb array of holes to form
a multiply connected geometry and subjected to a perpendicular magnetic field.
Film magnetoresistances on the superconducting side of the SIT oscillate with a
period dictated by the superconducting flux quantum and the areal hole density.
The oscillations disappear close to the SIT critical point to leave a
monotonically rising magnetoresistance that persists in the insulating phase.
These observations indicate that the Cooper pair phase coherence length, which
is infinite in the superconducting phase, collapses to a value less than the
interhole spacing at this SIT. This behavior is inconsistent with the gradual
reduction of the phase coherence length expected for a bosonic, phase
fluctuation driven SIT. This result starkly contrasts with previous
observations of oscillations persisting in the insulating phase of other films
implying that there must be at least two distinct classes of disorder tuned
SITs.


title: A New Hole Density as a Stability Measure for Boron Fullerenes

abstract:
  We investigate the stability of boron fullerene sets B76, B78 and B82. We
evaluate the ground state energies, nucleus-independent chemical shift (NICS),
the binding energies per atom and the band gap values by means of
first-principles methods. We construct our fullerene design by capping of
pentagons and hexagons of B60 cage in such a way that the total number of atoms
is preserved. In doing so, a new hole density definition is proposed such that
each member of a fullerene group has a different hole density which depends on
the capping process. Our analysis reveal that each boron fullerene set has its
lowest-energy configuration around the same normalized hole density and the
most stable cages are found in the fullerene groups which have relatively large
difference between the maximum and the minimum hole densities. The result is a
new stability measure relating the cage geometry characterized by the hole
density to the relative energy.


title: High-Rate Regenerating Codes Through Layering

abstract:
  In this paper, we provide explicit constructions for a class of exact-repair
regenerating codes that possess a layered structure. These regenerating codes
correspond to interior points on the storage-repair-bandwidth tradeoff, and
compare very well in comparison to scheme that employs space-sharing between
MSR and MBR codes. For the parameter set $(n,k,d=k)$ with $n < 2k-1$, we
construct a class of codes with an auxiliary parameter $w$, referred to as
canonical codes. With $w$ in the range $n-k < w < k$, these codes operate in
the region between the MSR point and the MBR point, and perform significantly
better than the space-sharing line. They only require a field size greater than
$w+n-k$. For the case of $(n,n-1,n-1)$, canonical codes can also be shown to
achieve an interior point on the line-segment joining the MSR point and the
next point of slope-discontinuity on the storage-repair-bandwidth tradeoff.
Thus we establish the existence of exact-repair codes on a point other than the
MSR and the MBR point on the storage-repair-bandwidth tradeoff. We also
construct layered regenerating codes for general parameter set $(n,k<d,k)$,
which we refer to as non-canonical codes. These codes also perform
significantly better than the space-sharing line, though they require a
significantly higher field size. All the codes constructed in this paper are
high-rate, can repair multiple node-failures and do not require any computation
at the helper nodes. We also construct optimal codes with locality in which the
local codes are layered regenerating codes.


title:
Periodic points in towers of finite fields for polynomials associated to
  algebraic groups

abstract:
  We find the limiting proportion of periodic points in towers of finite fields
for polynomial maps associated to algebraic groups, namely pure power maps z^d
and Chebyshev polynomials.


title:
Cooper Pair Insulator phase induced in amorphous Pb$_0.9$Bi$_0.1$ thin
  films

abstract:
  A Cooper pair insulator (CPI) phase emerges near the superconductor-insulator
transitions of a number of strongly-disordered thin film systems. Much recent
study has focused on a mechanism driving the underlying Cooper pair
localization. We present data showing that a CPI phase develops in amorphous
Pb$_{0.9}$Bi$_{0.1}$ films deposited onto nano-porous anodized aluminum oxide
surfaces just as it has been shown to develop for a-Bi films. This result
confirms the assertion that the CPI phase emerges due to the structure of the
substrate. It supports the picture that nanoscale film thickness variations
induced by the substrate drive the localization. Moreover, it implies that the
CPI phase can be induced in any superconducting material that can be deposited
onto this surface.


title:
Transfer matrix for treating stratified media including birefringent
  crystals

abstract:
  Birefringent crystals are extensively used to manipulate polarized light. The
generalized transfer matrix developed allows efficient calculation of the full
polarization state of light transmitted through and reflected by a stack of
arbitrarily-many discrete layers of isotropic and birefringent materials at any
frequency and angle of incidence. The matrix of a uniaxial birefringent crystal
with arbitrary rotation is calculated, along with its reduction to the matrix
of an isotropic medium. This method is of great practical importance where
tight control of systematic effects is needed in optical systems employing
birefringent crystals, one example being wave plates used by cosmic microwave
background polarimetry with wide field-of-view telescopes.


title:
Performance of transducers with segmented piezoelectric stacks using
  materials with high electromechanical coupling coefficient

abstract:
  Underwater acoustic transducers often include a stack of thickness polarized
piezoelectric material pieces of alternating polarity interspersed with
electrodes, bonded together and electrically connected in parallel. The stack
is normally much shorter than a quarter wavelength at the fundamental resonance
frequency, so that the mechanical behavior of the transducer is not affected by
the segmentation. When the transducer bandwidth is less than a half octave, as
has conventionally been the case, stack segmentation has no significant effect
on the mechanical behavior of the device. However, when a high coupling
coefficient material such as PMN-PT is used to achieve a wider bandwidth, the
difference between a segmented stack and a similar piezoelectric section with
electrodes only at the two ends can be significant. This paper investigates the
effects of stack segmentation on the performance of wideband underwater
acoustic transducers, particularly tonpilz transducer elements. Included is
discussion of transducer designs using single crystal piezoelectric material
with high coupling coefficient compared with more traditional PZT ceramics.


title:
Probing the Dawn of Galaxies at z~9-12: New Constraints from HUDF12/XDF
  and CANDELS Data

abstract:
  We present a comprehensive analysis of z>8 galaxies based on ultra-deep
WFC3/IR data. We constrain the evolution of the UV luminosity function (LF) and
luminosity densities from z~11 to z~8 by exploiting all the WFC3/IR data over
the Hubble Ultra-Deep Field from the HUDF09 and the new HUDF12 program, in
addition to the HUDF09 parallel field data, as well as wider area WFC3/IR
imaging over GOODS-South. Galaxies are selected based on the Lyman Break
Technique in three samples centered around z~9, z~10 and z~11, with seven z~9
galaxy candidates, and one each at z~10 and z~11. We confirm a new z~10
candidate (with z=9.8+-0.6) that was not convincingly identified in our first
z~10 sample. The deeper data over the HUDF confirms all our previous z>~7.5
candidates as genuine high-redshift candidates, and extends our samples to
higher redshift and fainter limits (H_160~29.8 mag). We perform one of the
first estimates of the z~9 UV LF and improve our previous constraints at z~10.
Extrapolating the lower redshift UV LF evolution should have revealed 17 z~9
and 9 z~10 sources, i.e., a factor ~3x and 9x larger than observed. The
inferred star-formation rate density (SFRD) in galaxies above 0.7 M_sun/yr
decreases by 0.6+-0.2 dex from z~8 to z~9, in good agreement with previous
estimates. The low number of sources found at z>8 is consistent with a very
rapid build-up of galaxies across z~10 to z~8. From a combination of all
current measurements, we find a best estimate of a factor 10x decrease in the
SFRD from z~8 to z~10, following (1+z)^(-11.4+-3.1). Our measurements thus
confirm our previous finding of an accelerated evolution beyond z~8, and
signify a rapid build-up of galaxies with M_UV<-17.7 within only ~200 Myr from
z~10 to z~8, in the heart of cosmic reionization.


title:
UHECR escape mechanisms for protons and neutrons from GRBs, and the
  cosmic ray-neutrino connection

abstract:
  The paradigm that gamma-ray burst (GRB) fireballs are the sources of the
ultra-high energy cosmic rays (UHECRs) is being probed by neutrino
observations. Very stringent bounds can be obtained from the cosmic ray
(proton)--neutrino connection, assuming that the UHECRs escape as neutrons. In
this study, we identify three different regimes as a function of the fireball
parameters: the standard "one neutrino per cosmic ray" case, the optically
thick (to neutron escape) case, and the case where leakage of protons from the
boundaries of the shells (direct escape) dominates. In the optically thick
regime, photomeson production is very efficient, and more neutrinos will be
emitted per cosmic ray than in the standard case, whereas in the direct
escape-dominated regime, more cosmic rays than neutrinos will be emitted. We
demonstrate that, for efficient proton acceleration, which is required to
describe the observed UHECR spectrum, the standard case only applies to a very
narrow region of the fireball parameter space. We illustrate with several
observed examples that conclusions on the cosmic ray--neutrino connection will
depend on the actual burst parameters. We show that the definition of the pion
production efficiency currently used by the IceCube collaboration
underestimates the neutrino production in the optically thick case. Finally, we
point out that the direct escape component leads to a spectral break in the
cosmic ray spectrum emitted from a single source. The resulting "two-component
model" can be used to even more strongly pronounce the spectral features of the
observed UHECR spectrum than the dip model.


title: Intrinsic Spin Seebeck Effect in Au/YIG

abstract:
  The acute magnetic proximity effects in Pt/YIG compromise the suitability of
Pt as a spin current detector. We show that Au/YIG, with no anomalous Hall
effect and a negligible magnetoresistance, allows the measurements of the
intrinsic spin Seebeck effect with a magnitude much smaller than that in
Pt/YIG. The experiment results are consistent with the spin-polarized
density-functional calculations for Pt with a sizable and Au with a negligible
magnetic moment near the interface with YIG.


title: Microlens Surveys are a Powerful Probe of Asteroids

abstract:
  While of order a million asteroids have been discovered, the number in
rigorously controlled samples that have precise orbits and rotation periods, as
well as well-measured colors, is relatively small. In particular, less than a
dozen main-belt asteroids with estimated diameters D<3 km, have excellent
rotation periods. We show how existing and soon-to-be-acquired microlensing
data can yield a large asteroid sample with precise orbits and rotation
periods, which will include roughly 6% of all asteroids with maximum brightness
I<18.1 and lying within 10 deg of the ecliptic. This sample will be dominated
by small and very small asteroids, down to D~1 km. We also show how asteroid
astrometry could turn current narrow-angle OGLE proper motions of bulge stars
into wide-angle proper motions. This would enable one to measure the
proper-motion gradient across the Galactic bar.


title: Response to a twist on systems with Zp symmetry

abstract:
  We study response to a twist in the two-dimensional p-state clock model,
which has the discrete Zp symmetry. The response is measured in terms of
helicity modulus, which is usually defined with respect to an infinitesimal
twist. However, we demonstrate that such a definition is inappropriate for the
clock model. The helicity modulus must be defined with respect to a finite,
quantized twist which matches the discrete Zp symmetry of the model. Recent
numerical results, which casted doubt on the standard picture that two
Berezinskii-Kosterlitz-Thouless transitions occur for p > 4, are rather a
consequence of use of the inappropriate quantity. Numerical calculation of the
appropriately defined helicity modulus indeed supports the standard picture.


title:
Small-scale structure of the interstellar medium towards rho Oph stars:
  diffuse band observations

abstract:
  We present an investigation of small-scale-structure in the distribution of
large molecules/dust in the interstellar medium through observations of diffuse
interstellar bands (DIBs). High signal-to-noise optical spectra were recorded
towards the stars rho Oph A, B, C and DE using the University College London
Echelle Spectrograph (UCLES) on the Anglo-Australian Telescope. The strengths
of some of the DIBs are found to differ by about 5-9 % between the close binary
stars rho Oph A and B, which are separated by a projected distance on the sky
of only ~344 AU. This is the first star-system in which such small-scale DIB
strength variations have been reported. The observed variations are attributed
to differences between a combination of carrier abundance and the physical
conditions present along each sightline. The sightline towards rho Oph C
contains relatively dense, molecule-rich material and has the strongest
\lambda\lambda 5850 and 4726 DIBs. The gas towards DE is more diffuse and is
found to exhibit weak C_2 (blue) DIBs and strong yellow/red DIBs. The
differences in diffuse band strengths between lines of sight are, in some
cases, significantly greater in magnitude than the corresponding variations
among atomic and diatomic species, indicating that the DIBs can be sensitive
tracers of interstellar cloud conditions.


title: Evidence for a Milky Way Tidal Stream Reaching Beyond 100 kpc

abstract:
  We present the analysis of 1,207 RR Lyrae found in photometry taken by the
Catalina Survey's Mount Lemmon telescope. By combining accurate distances for
these stars with measurements for ~14,000 type-AB RR Lyrae from the Catalina
Schmid telescope, we reveal an extended association that reaches Galactocentric
distances beyond 100 kpc and overlaps the Sagittarius streams system. This
result confirms earlier evidence for the existence of an outer halo tidal
stream resulting from a disrupted stellar system. By comparing the RR Lyrae
source density with that expected based on halo models, we find the detection
has ~8 sigma significance. We investigate the distances, radial velocities,
metallicities, and period-amplitude distribution of the RR Lyrae. We find that
both radial velocities and distances are inconsistent with current models of
the Sagittarius stream. We also find tentative evidence for a division in
source metallicities for the most distant sources. Following prior analyses, we
compare the locations and distances of the RR Lyrae with photometrically
selected candidate horizontal branch stars and find supporting evidence that
this structure spans at least 60 deg of the sky. We investigate the prospects
of an association between the stream and unusual globular cluster NGC 2419.


title: Phases of large $N$ vector Chern-Simons theories on $S^2 \times S^1$

abstract:
  We study the thermal partition function of level $k$ U(N) Chern-Simons
theories on $S^2$ interacting with matter in the fundamental representation. We
work in the 't Hooft limit, $N,k\to\infty$, with $\lambda = N/k$ and $\frac{T^2
V_{2}}{N}$ held fixed where $T$ is the temperature and $V_{2}$ the volume of
the sphere. An effective action proposed in arXiv:1211.4843 relates the
partition function to the expectation value of a `potential' function of the
$S^1$ holonomy in pure Chern-Simons theory; in several examples we compute the
holonomy potential as a function of $\lambda$. We use level rank duality of
pure Chern-Simons theory to demonstrate the equality of thermal partition
functions of previously conjectured dual pairs of theories as a function of the
temperature. We reduce the partition function to a matrix integral over
holonomies. The summation over flux sectors quantizes the eigenvalues of this
matrix in units of ${2\pi \over k}$ and the eigenvalue density of the holonomy
matrix is bounded from above by $\frac{1}{2 \pi \lambda}$. The corresponding
matrix integrals generically undergo two phase transitions as a function of
temperature. For several Chern-Simons matter theories we are able to exactly
solve the relevant matrix models in the low temperature phase, and determine
the phase transition temperature as a function of $\lambda$. At low
temperatures our partition function smoothly matches onto the $N$ and $\lambda$
independent free energy of a gas of non renormalized multi trace operators. We
also find an exact solution to a simple toy matrix model; the large $N$
Gross-Witten-Wadia matrix integral subject to an upper bound on eigenvalue
density.


title:
Properties of M31. II: A Cepheid disk sample derived from the first year
  of PS1 PAndromeda data

abstract:
  We present a sample of Cepheid variable stars towards M31 based on the first
year of regular M31 observations of the PS1 survey in the r_P1 and i_P1
filters. We describe the selection procedure for Cepheid variable stars from
the overall variable source sample and develop an automatic classification
scheme using Fourier decomposition and the location of the instability strip.
We find 1440 fundamental mode (classical \delta) Cep stars, 126 Cepheids in the
first overtone mode, and 147 belonging to the Population II types. 296 Cepheids
could not be assigned to one of these classes and 354 Cepheids were found in
other surveys. These 2009 Cepheids constitute the largest Cepheid sample in M31
known so far and the full catalog is presented in this paper. We briefly
describe the properties of our sample in its spatial distribution throughout
the M31 galaxy, in its age properties, and we derive an apparent
period-luminosity relation (PLR) in our two bands. The Population I Cepheids
nicely follow the dust pattern of the M31 disk, whereas the 147 Type II
Cepheids are distributed throughout the halo of M31. We outline the time
evolution of the star formation in the major ring found previously and find an
age gradient. A comparison of our PLR to previous results indicates a curvature
term in the PLR.


title:
Submm/mm Galaxy Counterpart Identification Using a Characteristic
  Density Distribution

abstract:
  We present a new submm/mm galaxy counterpart identification technique which
builds on the use of Spitzer IRAC colors as discriminators between likely
counterparts and the general IRAC galaxy population. Using 102 radio- and
SMA-confirmed counterparts to AzTEC sources across three fields (GOODS-N,
GOODS-S, and COSMOS), we develop a non-parametric IRAC color-color
characteristic density distribution (CDD), which, when combined with positional
uncertainty information via likelihood ratios, allows us to rank all potential
IRAC counterparts around SMGs and calculate the significance of each ranking
via the reliability factor. We report all robust and tentative radio
counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well
as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as
determined by our technique. We demonstrate that the technique is free of radio
bias and thus applicable regardless of radio detections. For observations made
with a moderate beamsize (~18"), this technique identifies ~85 per cent of SMG
counterparts. For much larger beamsizes (>30"), we report identification rates
of 33-49 per cent. Using simulations, we demonstrate that this technique is an
improvement over using positional information alone for observations with
facilities such as AzTEC on the LMT and SCUBA-2 on JCMT.


title: Wave Functions of Bosonic Symmetry Protected Topological Phases

abstract:
  We study the structure of the ground state wave functions of bosonic Symmetry
Protected Topological (SPT) insulators in 3 space dimensions. We demonstrate
that the differences with conventional insulators are captured simply in a dual
vortex description. As an example we show that a previously studied bosonic
topological insulator with both global U(1) and time-reversal symmetry can be
described by a rather simple wave function written in terms of dual "vortex
ribbons". The wave function is a superposition of all the vortex ribbon
configurations of the boson, and a factor (-1) is associated with each
self-linking of the vortex ribbons. This wave function can be conveniently
derived using an effective field theory of the SPT in the strong coupling
limit, and it naturally explains all the phenomena of this SPT phase discussed
previously. The ground state structure for other 3d bosonic SPT phases are also
discussed similarly in terms of vortex loop gas wave functions. We show that
our methods reproduce known results on the ground state structure of some 2d
SPT phases.


title: Scale Anomaly as the Origin of Time

abstract:
  We explore the problem of time in quantum gravity in a point-particle
analogue model of scale-invariant gravity. If quantized after reduction to true
degrees of freedom, it leads to a time-independent Schr\"odinger equation. As
with the Wheeler--DeWitt equation, time disappears, and a frozen formalism that
gives a static wavefunction on the space of possible shapes of the system is
obtained. However, if one follows the Dirac procedure and quantizes by imposing
constraints, the potential that ensures scale invariance gives rise to a
conformal anomaly, and the scale invariance is broken. A behaviour closely
analogous to renormalization-group (RG) flow results. The wavefunction acquires
a dependence on the scale parameter of the RG flow. We interpret this as time
evolution and obtain a novel solution of the problem of time in quantum
gravity. We apply the general procedure to the three-body problem, showing how
to fix a natural initial value condition, introducing the notion of complexity.
We recover a time-dependent Schr\"odinger equation with a repulsive
cosmological force in the `late-time' physics and we analyse the role of the
scale invariant Planck constant. We suggest that several mechanisms presented
in this model could be exploited in more general contexts.


title:
Hyperboloidal Einstein-matter evolution and tails for scalar and
  Yang-Mills fields

abstract:
  We show how matter can be included in a constrained ADM-like formulation of
the Einstein equations on constant mean curvature surfaces. Previous results on
the regularity of the equations at future null infinity are unaffected by the
addition of matter with tracefree energy-momentum tensor. Two examples are
studied in detail, a conformally coupled scalar field and a Yang-Mills field.
We first derive the equations under no symmetry assumptions and then reduce
them to spherical symmetry. Both sectors (gravitational and sphaleron) of the
spherically symmetric Yang-Mills field are included. We implement this scheme
numerically in order to study late-time tails of scalar and Yang-Mills fields
coupled to the Einstein equations. We are able to evolve spacetimes that
disperse to flat space, accrete onto a given black hole or collapse to a black
hole from regular initial data. The sphaleron sector of Yang-Mills is found to
exhibit some nontrivial gauge dynamics.


title: Infrared self-consistent solutions of bispinor QED3

abstract:
  Quantum electrodynamics in three dimensions in the bispinor formulation is
considered. It is shown that the Dyson-Schwinger equations for fermion and
boson propagators may be self-consistently solved in the infrared domain if on
uses the Salam's vertex function. The parameters defining the behavior of the
propagators are found numerically for different values of coupling constant and
gauge parameter. For weak coupling the approximated analytical solutions are
obtained. The renormalized gauge boson propagator (transverse part) is shown in
the infrared domain to be practically gauge independent.