title:
Near-best $C^2$ quartic spline quasi-interpolants on type-6 tetrahedral
  partitions of bounded domains

abstract:
  In this paper, we present new quasi-interpolating spline schemes defined on
3D bounded domains, based on trivariate $C^2$ quartic box splines on type-6
tetrahedral partitions and with approximation order four. Such methods can be
used for the reconstruction of gridded volume data. More precisely, we propose
near-best quasi-interpolants, i.e. with coefficient functionals obtained by
imposing the exactness of the quasi-interpolants on the space of polynomials of
total degree three and minimizing an upper bound for their infinity norm. In
case of bounded domains the main problem consists in the construction of the
coefficient functionals associated with boundary generators (i.e. generators
with supports not completely inside the domain), so that the functionals
involve data points inside or on the boundary of the domain.
  We give norm and error estimates and we present some numerical tests,
illustrating the approximation properties of the proposed quasi-interpolants,
and comparisons with other known spline methods. Some applications with real
world volume data are also provided.


title: Massive conformal gravity

abstract:
  In this article we construct a massive theory of gravity that is invariant
under conformal transformations. The massive action of the theory depend on the
metric tensor and a scalar field, which are considered as the only field
variables. We find the vacuum field equations of the theory and the solution of
its Newtonian limit.


title:
Framed sheaves on root stacks and supersymmetric gauge theories on ALE
  spaces

abstract:
  We develop a new approach to the study of supersymmetric gauge theories on
ALE spaces using the theory of framed sheaves on root toric stacks, which
illuminates relations with gauge theories on $\mathbb{R}^4$ and with
two-dimensional conformal field theory. We construct a stacky compactification
of the minimal resolution $X_k$ of the $A_{k-1}$ toric singularity
$\mathbb{C}^2/\mathbb{Z}_k$, which is a projective toric orbifold
$\mathscr{X}_k$ such that $\mathscr{X}_k\setminus X_k$ is a
$\mathbb{Z}_k$-gerbe. We construct moduli spaces of torsion free sheaves on
$\mathscr{X}_k$ which are framed along the compactification gerbe. We prove
that this moduli space is a smooth quasi-projective variety, compute its
dimension, and classify its fixed points under the natural induced toric
action. We use this construction to compute the partition functions and
correlators of chiral BPS operators for $\mathcal{N}=2$ quiver gauge theories
on $X_k$ with nontrivial holonomies at infinity. The partition functions are
computed with and without couplings to bifundamental matter hypermultiplets and
expressed in terms of toric blowup formulas, which relate them to the
corresponding Nekrasov partition functions on the affine toric subsets of
$X_k$. We compare our new partition functions with previous computations,
explore their connections to the representation theory of affine Lie algebras,
and find new constraints on fractional instanton charges in the coupling to
fundamental matter. We show that the partition functions in the low energy
limit are characterised by the Seiberg-Witten curves, and in some cases also by
suitable blowup equations involving Riemann theta-functions on the
Seiberg-Witten curve with characteristics related to the nontrivial holonomies.


title: A Pricing-Based Cooperative Spectrum Sharing Stackelberg Game

abstract:
  We consider the problem of cooperative spectrum sharing among a primary user
(PU) and multiple secondary users (SUs) under quality of service (QoS)
constraints. The SUs network is controlled by the PU through a relay which gets
a revenue for amplifying and forwarding the SUs signals to their respective
destinations. The relay charges each SU a different price depending on its
received signal-to-interference and-noise ratio (SINR). The relay can control
the SUs network and maximize any desired PU utility function. The PU utility
function represents its rate, which is affected by the SUs access, and its
gained revenue to allow the access of the SUs. The SU network can be formulated
as a game in which each SU wants to maximize its utility function; the problem
is formulated as a Stackelberg game. Finally, the problem of maximizing the
primary utility function is solved through three different approaches, namely,
the optimal, the heuristic and the suboptimal algorithms.


title:
Hierarchical Testing in the High-Dimensional Setting with Correlated
  Variables

abstract:
  We propose a method for testing whether hierarchically ordered groups of
potentially correlated variables are significant for explaining a response in a
high-dimensional linear model. In presence of highly correlated variables, as
is very common in high-dimensional data, it seems indispensable to go beyond an
approach of inferring individual regression coefficients, and we show that
detecting smallest groups of variables (MTDs: minimal true detections) is
realistic. Thanks to the hierarchy among the groups of variables, powerful
multiple testing adjustment is possible which leads to a data-driven choice of
the resolution level for the groups. Our procedure, based on repeated sample
splitting, is shown to asymptotically control the familywise error rate and we
provide empirical results for simulated and real data which complement the
theoretical analysis. Supplementary materials for this article are available
after the References.


title: Braid Representations from Unitary Braided Vector Spaces

abstract:
  We investigate braid group representations associated with unitary braided
vector spaces, focusing on a conjecture that such representations should have
virtually abelian images in general and finite image provided the braiding has
finite order. We verify this conjecture for the two infinite families of
Gaussian and group-type braided vector spaces, as well as the generalization to
quasi-braided vector spaces of group-type.


title:
Application of Wavelet-based Active Power Filter in Accelerator Magnet
  Power Supply

abstract:
  As modern accelerators demand excellent stability to magnet power supply
(PS), it is necessary to decrease harmonic currents passing magnets. Aim at
depressing rappel current from PS in Beijing electron-positron collider II, a
wavelet-based active power filter (APF) is proposed in this paper. APF is an
effective device to improve the quality of currents. As a countermeasure to
these harmonic currents, the APF circuit generates a harmonic current,
countervailing harmonic current from PS. An active power filter based on
wavelet transform is proposed in this paper. Discrete wavelet transform is used
to analyze the harmonic components in supply current, and active power filter
circuit works according to the analysis results. At end of this paper, the
simulation and experiment results are given to prove the effect of the
mentioned Active power filter.


title:
Distributional Models and Deep Learning Embeddings: Combining the Best
  of Both Worlds

abstract:
  There are two main approaches to the distributed representation of words:
low-dimensional deep learning embeddings and high-dimensional distributional
models, in which each dimension corresponds to a context word. In this paper,
we combine these two approaches by learning embeddings based on
distributional-model vectors - as opposed to one-hot vectors as is standardly
done in deep learning. We show that the combined approach has better
performance on a word relatedness judgment task.


title: Lyapunov exponents in resonance multiplets

abstract:
  The problem of estimating the maximum Lyapunov exponents of the motion in a
multiplet of interacting nonlinear resonances is considered for the case when
the resonances have comparable strength. The corresponding theoretical
approaches are considered for the multiplets of two, three, and infinitely many
resonances (i.e., doublets, triplets, and "infinitets"). The analysis is based
on the theory of separatrix and standard maps. A "multiplet separatrix map" is
introduced, valid for description of the motion in the resonance multiplet
under certain conditions. In numerical experiments it is shown that, at any
given value of the adiabaticity parameter (which controls the degree of
interaction/overlap of resonances in the multiplet), the value of the maximum
Lyapunov exponent in the multiplet of equally-spaced equally-sized resonances
is minimal in the doublet case and maximal in the infinitet case. This is
consistent with the developed theory.


title:
Numerical Simulation of Fluid-Structure Interaction Problems with
  Hyperelastic Models I: A Partitioned Approach

abstract:
  In this work, we consider fluid-structure interaction simulation with
nonlinear hyperelastic models in the solid part. We use a partitioned approach
to deal with the coupled nonlinear fluid-structure interaction problems. We
focus on handling the nonlinearity of the fluid and structure sub-problems, the
near-incompressibility of materials, the stabilization of employed finite
element discretization, and the robustness and efficiency of Krylov subspace
and algebraic multigrid methods for the linearized algebraic equations.


title:
Same Initial States Attack in Yang et al.'s Quantum Private Comparison
  Protocol and the Improvement

abstract:
  In Yang et al.'s literatures (J. Phys. A: Math. 42, 055305, 2009; J. Phys.
A:Math. 43, 209801, 2010), a quantum private comparison protocol based on Bell
states and hash function is proposed, which aims to securely compare the
equality of two participants' information with the help of a dishonest third
party (TP). However, this study will point out their protocol cannot resist a
special kind of attack, TP's same initial states attack, which is presented in
this paper. That is, the dishonest TP can disturb the comparison result without
being detected through preparing the same initial states. Finally, a simple
improvement is given to avoid the attack.


title:
GHz photon-activated hopping between localized states in a silicon
  quantum dot

abstract:
  We discuss the effects of gigahertz photon irradiation on a degenerately
phosphorous-doped silicon quantum dot, in particular, the creation of voltage
offsets on gate leads and the tunneling of one or two electrons via Coulomb
blockade lifting at 4.2K. A semi-analytical model is derived that explains the
main features observed experimentally. Ultimately both effects may provide an
efficient way to optically control and operate electrically isolated structures
by microwave pulses. In quantum computing architectures, these results may lead
to the use of microwave multiplexing to manipulate quantum states in a
multi-qubit configuration.


title: Width of the chaotic layer: maxima due to marginal resonances

abstract:
  Modern theoretical methods for estimating the width of the chaotic layer in
presence of prominent marginal resonances are considered in the perturbed
pendulum model of nonlinear resonance. The fields of applicability of these
methods are explicitly and precisely formulated. The comparative accuracy is
investigated in massive and long-run numerical experiments. It is shown that
the methods are naturally subdivided in classes applicable for adiabatic and
non-adiabatic cases of perturbation. It is explicitly shown that the pendulum
approximation of marginal resonance works good in the non-adiabatic case. In
this case, the role of marginal resonances in determining the total layer width
is demonstrated to diminish with increasing the main parameter \lambda (equal
to the ratio of the perturbation frequency to the frequency of small-amplitude
phase oscillations on the resonance). Solely the "bending effect" is important
in determining the total amplitude of the energy deviations of the
near-separatrix motion at \lambda > 7. In the adiabatic case, it is
demonstrated that the geometrical form of the separatrix cell can be described
analytically quite easily by means of using a specific representation of the
separatrix map. It is shown that the non-adiabatic (and, to some extent,
intermediary) case is most actual, in comparison with the adiabatic one, for
the physical or technical applications that concern the energy jumps in the
near-separatrix chaotic motion.


title:
What Transcription Factors Can't Do: On the Combinatorial Limits of Gene
  Regulatory Networks

abstract:
  A proof is presented that gene regulatory networks (GRNs) based solely on
transcription factors cannot control the development of complex multicellular
life. GRNs alone cannot explain the evolution of multicellular life in the
Cambrian Explosion. Networks are based on addressing systems which are used to
construct network links. The more complex the network the greater the number of
links and the larger the required address space. It has been assumed that
combinations of transcription factors generate a large enough address space to
form GRNs that are complex enough to control the development of complex
multicellular life. However, it is shown in this article that transcription
factors do not have sufficient combinatorial power to serve as the basis of an
addressing system for regulatory control of genomes in the development of
complex organisms. It is proven that given $n$ transcription factor genes in a
genome and address combinations of length $k$ then there are at most $n/k$
k-length transcription factor addresses in the address space. The complexity of
embryonic development requires a corresponding complexity of control
information in the cell and its genome. Therefore, a different addressing
system must exist to form the complex control networks required for complex
control systems. It is postulated that a new type of network evolved based on
an RNA-DNA addressing system that utilized and subsumed the extant GRNs. These
new developmental control networks are called CENES (for Control genes). The
evolution of these new higher networks would explain how the Cambrian Explosion
was possible. The architecture of these higher level networks may in fact be
universal (modulo syntax) in the genomes of all multicellular life.


title: Kinetic approaches to lactose operon induction and bimodality

abstract:
  The quasi-equilibrium approximation is acceptable when molecular interactions
are fast enough compared to circuit dynamics, but is no longer allowed when
cellular activities are governed by rare events. A typical example is the
lactose operon (lac), one of the most famous paradigms of transcription
regulation, for which several theories still coexist to describe its behaviors.
The lac system is generally analyzed by using equilibrium constants,
contradicting single-event hypotheses long suggested by Novick and Weiner
(1957). Enzyme induction as an all-or-none phenomenon. Proc. Natl. Acad. Sci.
USA 43, 553-566) and recently refined in the study of (Choi et al., 2008. A
stochastic single-molecule event triggers phenotype switching of a bacterial
cell. Science 322, 442-446). In the present report, a lac repressor
(LacI)-mediated DNA immunoprecipitation experiment reveals that the natural
LacI-lac DNA complex built in vivo is extremely tight and long-lived compared
to the time scale of lac expression dynamics, which could functionally
disconnect the abortive expression bursts and forbid using the standard modes
of lac bistability. As alternatives, purely kinetic mechanisms are examined for
their capacity to restrict induction through: (i) widely scattered derepression
related to the arrival time variance of a predominantly backward asymmetric
random walk and (ii) an induction threshold arising in a single window of
derepression without recourse to nonlinear multimeric binding and Hill
functions. Considering the complete disengagement of the lac repressor from the
lac promoter as the probabilistic consequence of a transient stepwise
mechanism, is sufficient to explain the sigmoidal lac responses as functions of
time and of inducer concentration. This sigmoidal shape can be misleadingly
interpreted as a phenomenon of equilibrium cooperativity classically used to
explain bistability, but which has been reported to be weak in this system.


title:
Global wellposedness of the equivariant Chern-Simons-Schr\"odinger
  equation

abstract:
  In this article we consider the initial value problem for the m-equivariant
Chern-Simons-Schr\"odinger model in two spatial dimensions with real-valued
coupling parameter g. This is a covariant NLS type problem that is
L^2-critical. We prove that at the critical regularity, for any integer-valued
equivariance index m, the initial value problem in the defocusing case (g < 1)
is globally wellposed and the solution scatters. The problem is focusing when g
>= 1, and in this case we prove that for nonnegative integer-valued
equivariance indices m there exist constants c = c_{m, g} such that, at the
critical regularity, the initial value problem is globally wellposed and the
solution scatters when the L^2 initial data phi_0 is m-equivariant and has
L^2-norm less than the square root of c_{m, g}. We also show that c_{m,
g}^{1/2} is equal to the minimum L^2 norm of a nontrivial m-equivariant
standing wave solution. In the self-dual g = 1 case, we have the exact
numerical values c_{m, 1} = 8*pi*(m + 1).


title: An Adaptive Dictionary Learning Approach for Modeling Dynamical Textures

abstract:
  Video representation is an important and challenging task in the computer
vision community. In this paper, we assume that image frames of a moving scene
can be modeled as a Linear Dynamical System. We propose a sparse coding
framework, named adaptive video dictionary learning (AVDL), to model a video
adaptively. The developed framework is able to capture the dynamics of a moving
scene by exploring both sparse properties and the temporal correlations of
consecutive video frames. The proposed method is compared with state of the art
video processing methods on several benchmark data sequences, which exhibit
appearance changes and heavy occlusions.


title: The dynamical temperature and the standard map

abstract:
  Numerical experiments with the standard map at high values of the
stochasticity parameter reveal the existence of simple analytical relations
connecting the volume and the dynamical temperature of the chaotic component of
the phase space.


title: Global gradient estimates for the $p(\cdot)$-Laplacian

abstract:
  We consider Calder\'on-Zygmund type estimates for the non-homogeneous
$p(\cdot)$-Laplacian system $ -\text{div}(|D u|^{p(\cdot)-2} Du) =
-\text{div}(|G|^{p(\cdot)-2} G),$ where $p$ is a variable exponent. We show
that $|G|^{p(\cdot)} \in L^q(\mathbb{R}^n)$ implies $|D u|^{p(\cdot)} \in
L^q(\mathbb{R}^n)$ for any $q \geq 1$. We also prove local estimates
independent of the size of the domain and introduce new techniques to variable
analysis.


title:
Interim recommendations for the evaluation of Higgs production cross
  sections and branching ratios at the LHC in the Two-Higgs-Doublet Model

abstract:
  In this note we give interim recommendations on how to evaluate LHC cross
sections for (neutral) Higgs production and Higgs branching ratios in the
general (CP-conserving) Two-Higgs-Doublet Model (2HDM). The current status of
available higher-order corrections to Higgs production and decay in this model
is discussed, and the existing public codes implementing these calculations are
described. Numerical results are presented for a set of reference scenarios,
demonstrating the very good agreement between the results obtained using
different programs.


title: Quantum Private Comparison: A Review

abstract:
  As an important branch of quantum secure multiparty computation, quantum
private comparison (QPC) has attracted more and more attention recently. In
this paper, according to the quantum implementation mechanism that these
protocols used, we divide these protocols into three categories: The quantum
cryptography QPC, the superdense coding QPC, and the entanglement swapping QPC.
And then, a more in-depth analysis on the research progress, design idea, and
substantive characteristics of corresponding QPC categories is carried out,
respectively. Finally, the applications of QPC and quantum secure multi-party
computation issues are discussed and, in addition, three possible research
mainstream directions are pointed out.


title:
Frustrated ferromagnetic spin chains: a variational approach to
  chirality transitions

abstract:
  We study the energy per particle of a one-dimensional
ferromagnetic/anti-ferromagnetic frustrated spin chain with nearest and
next-to-nearest interactions close to the helimagnet/ferromagnet transition
point as the number of particles diverges. We rigorously prove the emergence of
chiral ground states and we compute, by performing the Gamma-limits of proper
renormalizations and scalings, the energy for a chirality transition.


title: Rindler Modified Schwarzschild Geodesics

abstract:
  The mysterious attractive constant radial force acted in the past on Pioneer
spacecrafts - the so-called Pioneer anomaly - is considered within the context
of Rindler acceleration. As an idea this is tempting since it is reminiscent of
the cosmological constant. Fortunately the anomalous force acts radially toward
the sun so that it differs from the mission of a cosmological constant. Without
resorting to the physical source responsible for such a term we investigate the
modified Schwarzschild geodesics. The Rindler acceleration naturally affects
all massive / massless particle orbits. Stable orbits may turn unstable and
vice versa with a finely-tuned acceleration parameter. The overall role of the
extra term, given its attractive feature is to provide confinement in the
radial geodesics.


title: Effects of the equilibrium model on impurity transport in tokamaks

abstract:
  Gyrokinetic simulations of ion temperature gradient mode and trapped electron
mode driven impurity transport in a realistic tokamak geometry are presented
and compared with results using simplified geometries. The gyrokinetic results,
obtained with the GENE code in both linear and non-linear modes are compared
with data and analysis for a dedicated impurity injection discharge at JET. The
impact of several factors on heat and particle transport is discussed, lending
special focus to tokamak geometry and rotational shear. To this end, results
using s-alpha and concentric circular equilibria are compared with results with
magnetic geometry from a JET experiment. To further approach experimental
conditions, non-linear gyrokinetic simulations are performed with collisions
and a carbon background included.
  The impurity peaking factors, computed by finding local density gradients
corresponding to zero particle flux, are discussed. The impurity peaking
factors are seen to be reduced by a factor of ~2 in realistic geometry compared
with the simplified geometries, due to a reduction of the convective pinch. It
is also seen that collisions reduce the peaking factor for low-Z impurities,
while increasing it for high charge numbers, which is attributed to a shift in
the transport spectra towards higher wavenumbers with the addition of
collisions. With the addition of roto-diffusion, an overall reduction of the
peaking factors is observed, but this decrease is not sufficient to explain the
flat carbon profiles seen at JET.


title: Finite volume form factors in the presence of integrable defects

abstract:
  We developed the theory of finite volume form factors in the presence of
integrable defects. These finite volume form factors are expressed in terms of
the infinite volume form factors and the finite volume density of states and
incorporate all polynomial corrections in the inverse of the volume. We tested
our results, in the defect Lee-Yang model, against numerical data obtained by
truncated conformal space approach (TCSA), which we improved by renormalization
group methods adopted to the defect case. To perform these checks we determined
the infinite volume defect form factors in the Lee-Yang model exactly,
including their vacuum expectation values. We used these data to calculate the
two point functions, which we compared, at short distance, to defect CFT. We
also derived explicit expressions for the exact finite volume one point
functions, which we checked numerically. In all of these comparisons excellent
agreement was found.


title:
Secure Quantum Private Comparison of Equality Based on Asymmetric W
  State

abstract:
  Recently, Liu et al. [Opt. Commun. 284, 3160, 2011] proposed a protocol for
quantum private comparison of equality (QPCE) based on sym- metric W state.
However, Li et al. [Eur. Phys. J. D. 66, 110, 2012] pointed out that there is a
flaw of information leak, and they proposed a new protocol based on EPR pairs.
While examining these two protocols, we find that there exists a same flaw: the
third party (TP) can know the comparison result. In this paper, through
introducing and constructing a special class of asymmet- ric W state, a secure
QPCE protocol based on this asymmetric W state is presented. Analysis shows the
present protocol can not only effectively avoid the information leak found by
Li et al, but also ensure TP would not get any information about the comparison
result.


title: Multimodal Transitions for Generative Stochastic Networks

abstract:
  Generative Stochastic Networks (GSNs) have been recently introduced as an
alternative to traditional probabilistic modeling: instead of parametrizing the
data distribution directly, one parametrizes a transition operator for a Markov
chain whose stationary distribution is an estimator of the data generating
distribution. The result of training is therefore a machine that generates
samples through this Markov chain. However, the previously introduced GSN
consistency theorems suggest that in order to capture a wide class of
distributions, the transition operator in general should be multimodal,
something that has not been done before this paper. We introduce for the first
time multimodal transition distributions for GSNs, in particular using models
in the NADE family (Neural Autoregressive Density Estimator) as output
distributions of the transition operator. A NADE model is related to an RBM
(and can thus model multimodal distributions) but its likelihood (and
likelihood gradient) can be computed easily. The parameters of the NADE are
obtained as a learned function of the previous state of the learned Markov
chain. Experiments clearly illustrate the advantage of such multimodal
transition distributions over unimodal GSNs.


title: Hadron masses and baryonic scales in $G_2$-QCD at finite density

abstract:
  The QCD phase diagram at densities relevant to neutron stars remains elusive,
mainly due to the fermion-sign problem. At the same time, a plethora of
possible phases has been predicted in models. Meanwhile $G_2$-QCD, for which
the $SU(3)$ gauge group of QCD is replaced by the exceptional Lie group $G_2$,
does not have a sign problem and can be simulated at such densities using
standard lattice techniques. It thus provides benchmarks to models and
functional continuum methods, and it serves to unravel the nature of possible
phases of strongly interacting matter at high densities. Instrumental in
understanding these phases is that $G_2$-QCD has fermionic baryons, and that it
can therefore sustain a baryonic Fermi surface. Because the baryon spectrum of
$G_2$-QCD also contains bosonic diquark and probably other more exotic states,
it is important to understand this spectrum before one can disentangle the
corresponding contributions to the baryon density. Here we present the first
systematic study of this spectrum from lattice simulations at different quark
masses. This allows us to relate the mass hierarchy, ranging from scalar
would-be-Goldstone bosons and intermediate vector bosons to the $G_2$-nucleons
and deltas, to individual structures observed in the total baryon density at
finite chemical potential.


title: New Cosmological Signatures from Double Field Theory

abstract:
  In cosmology, it has been a long-standing problem to establish a
\emph{parameter insensitive} evolution from an anisotropic phase to an
isotropic phase. On the other hand, it is of great importance to construct a
theory having extra dimensions as its intrinsic ingredients. We show that these
two problems are closely related and can naturally be solved simultaneously in
double field theory cosmology. Our derivations are based on general arguments
without any fine-tuning parameters. In addition, We find that when we begin
with FRW metric, the full spacetime metric of DFT totally agrees with
\emph{Kaluza-Klein theory}. There is a visible and invisible dimension exchange
between the pre- and post-big bangs. Our results indicate that double field
theory has profound physical consequences and the continuous
$O\left(D,D\right)$ is a very fundamental symmetry. This observation reinforces
the viewpoint that symmetries dictate physics.


title:
Undulations in a weakly interacting mechanically generated molecular
  braid under tension

abstract:
  We consider mechanically generated molecular braids composed of two molecules
where long range interactions between them can be considered to be very weak.
We describe a model that takes account of the thermal fluctuations of the
braid, steric interactions between the molecules, and external mechanical
forces. In this model, both sets of ends, of the two molecules, are considered
to be separated by a fixed distance apart much larger than the radius of the
braid. One set of ends are rotated to generate a braid of a certain number of
pitches (or turns), while the other set remains fixed. This model may describe
the situation in which the ends of each molecule are attached to a substrate
and a magnetic bead; to the latter a pulling force and rotational torque can be
applied. We discuss various aspects of our model. Most importantly, an
expression for the free energy is given, from which equations, determining the
various geometric parameters of the braid, can be obtained. By numerically
solving these equations, we give predictions from the model for the external
torque needed to produce a braid with a certain number of turns per bending
persistence length, as well as the end to end extension of the two molecules
for a given pulling force. Other geometric parameters, as well as the lateral
force required to keep the ends of the two molecules apart, are also
calculated.


title: Tumour Control Probability in Cancer Stem Cells Hypothesis

abstract:
  The tumour control probability (TCP) is a formalism derived to compare
various treatment regimens of radiation therapy, defined as the probability
that given a prescribed dose of radiation, a tumour has been eradicated or
controlled. In the traditional view of cancer, all cells share the ability to
divide without limit and thus have the potential to generate a malignant
tumour. However, an emerging notion is that only a sub-population of cells, the
so-called cancer stem cells (CSCs), are responsible for the initiation and
maintenance of the tumour. A key implication of the CSC hypothesis is that
these cells must be eradicated to achieve cures, thus we define TCP_S as the
probability of eradicating CSCs for a given dose of radiation. A cell surface
protein expression profile, such as CD44high/CD24low for breast cancer, is
often used as a biomarker to monitor CSCs enrichment. However, it is
increasingly recognized that not all cells bearing this expression profile are
necessarily CSCs, and in particular early generations of progenitor cells may
share the same phenotype. Thus, due to the lack of a perfect biomarker for
CSCs, we also define a novel measurable TCP_CD+, that is the probability of
eliminating or controlling biomarker positive cells. Based on these
definitions, we use stochastic methods and numerical simulations to compare the
theoretical TCP_S and the measurable TCP_CD+. We also use the measurable TCP to
compare the effect of various radiation protocols.


title: New structures in scattering amplitudes: a review

abstract:
  We review some recent developments in the understanding of field theories in
the perturbative regime. In particular, we discuss the notions of analyticity,
unitarity and locality, and therefore the singularity structure of scattering
amplitudes in general interacting theories. We describe their tree-level
structure and their on-shell representations, as well as the links between the
tree-level structure itself and the structure of the loop amplitudes. Finally,
we describe the on-shell diagrammatics recently proposed both on general
grounds and in the remarkable example of planar supersymmetric theories. This
review is partially based on lectures given at: Dipartimento di Fisica and
INFN, Universit\`a di Bologna; Departamento de F{\i}sica de Part{\i}culas,
Universidade de Santiago de Compostela; and as part of the program Strings@ar
Lectures on Advanced Topics of High Energy Physics held at the IAFE


title:
Local spectral equidistribution for degree 2 Siegel modular forms in
  level and weight aspects

abstract:
  We prove an equidistribution statement for the Satake parameters of the local
representations attached to Siegel cusp forms of degree $2$ of increasing level
and weight, counted with a certain arithmetic weight. We then apply this to
compute the symmetry type of a similarly weighted distribution of the low-lying
zeros of $L$-functions attached to these cusp forms.


title:
Three-wave interaction and Manley-Rowe relations in quantum
  hydrodynamics

abstract:
  The theory for nonlinear three-wave interaction in magnetized plasmas is
reconsidered using quantum hydrodynamics. The general coupling coefficients are
calculated for a generalized Bohm de Broglie term. It is found that the
Manley-Rowe relations are fulfilled only if the form of the particle dispersive
term coincides with the standard expression. The implications of our results
are discussed.


title: Braids and combinatorial knot Floer homology

abstract:
  We present a braid-theoretic approach to combinatorially computing knot Floer
homology. To a knot or link K, which is braided about the standard disk open
book decomposition for (S^3,\xi_std), we associate a corresponding
multi-pointed nice Heegaard diagram. We then describe an explicit algorithm for
computing the associated knot Floer homology groups. We compute explicit bounds
for the computational complexity of our algorithm and demonstrate that, in many
cases, it is significantly faster than the previous approach using grid
diagrams.


title:
Commutators of vector-valued intrinsic square functions on vector-valued
  generalized weighted Morrey spaces

abstract:
  In this paper, we will obtain the strong type and weak type estimates for
vector-valued analogues of intrinsic square functions in the generalized
weighted Morrey spaces $M^{\Phi,\varphi}_{w}(\mathbb{R}^n)$. We study the
boundedness of intrinsic square functions including the Lusin area integral,
Littlewood-Paley $\mathrm{g}$-function and $\mathrm{g}_{\lambda}^{*}$ -function
and their commutators on vector-valued generalized weighted Morrey spaces
$M^{\Phi,\varphi}_{w}(l_2)$. In all the cases the conditions for the
boundedness are given either in terms of Zygmund-type integral inequalities on
$\varphi(x,r)$ without assuming any monotonicity property of $\varphi(x,r)$ on
$r$.


title:
Gluon field fluctuations in nuclear collisions: Multiplicity and
  eccentricity distributions

abstract:
  We discuss different sources of fluctuations in nuclear collisions and their
realization in the IP-Glasma model. We present results for multiplicity
distributions in p+p and p+A collisions and compare eccentricity distributions
in A+A collisions to the flow harmonic distributions in 10 centrality classes
measured by the ATLAS collaboration.


title: On free products and amalgams of pomonoids

abstract:
  The study of amalgamation in the category of partially ordered monoids was
initiated by Fakhuruddin in the 1980s. In 1986 he proved that, in the category
of commutative pomonoids, every absolutely flat commutative pomonoid is a weak
amalgmation base and every commutative pogroup is a strong amalgamation base.
Some twenty years later, Bulman-Fleming and Sohail in 2011 extended this work
to what they referred to as pomonoid amalgams. In particular they proved that
pogroups are poamalgmation bases in the category of pomonoids. Sohail, also in
2011, proved that absolutely poflat commutative pomonoids are poamalgmation
bases in the category of commutative pomonoids. In the present paper we extend
the work on pomonoid amalgams by generalising the work of Renshaw on amalgams
of monoids and extension properties of acts over monoids.


title: The structure of Siegel modular forms modulo p and U(p) congruences

abstract:
  We determine the ring structure of Siegel modular forms of degree g modulo a
prime p, extending Nagaoka's result in the case of degree g=2. We characterize
U(p) congruences of Jacobi forms and Siegel modular forms, and surprisingly
find different behaviors of Siegel modular forms of even and odd degrees.


title: On Numerical Considerations for Modeling Reactive Astrophysical Shocks

abstract:
  Simulating detonations in astrophysical environments is often complicated by
numerical approximations to shock structure. A common prescription to ensure
correct detonation speeds and associated quantities is to prohibit burning
inside the numerically broadened shock (Fryxell et al. 1989). We have performed
a series of simulations to verify the efficacy of this approximation and to
understand how resolution and dimensionality might affect its use. Our results
show that, in one dimension, prohibiting burning in the shock is important
wherever the carbon burning length is not resolved, in keeping with the results
of Fryxell et al. (1989). In two dimensions, we find that the prohibition of
shock burning effectively inhibits the development of cellular structure for
all but the most highly-resolved cases. We discuss the possible impacts this
outcome may have on sub-grid models and detonation propagation in models of
Type Ia supernovae, including potential impacts on observables.


title: Massive Stellar Content of the Galactic Supershell GSH 305+01-24

abstract:
  The distribution of OB stars along with that of H$\alpha$, $^{12}$CO, dust
infrared emission, and neutral hydrogen is carried out in order to provide a
more complete picture of interactions of the young massive stars and the
observed supershell GSH 305+01-24. The studied field is located between
$299^\circ \le l \le 311^\circ$ and $-5^\circ \le b \le 7^\circ$. The
investigation is based on nearly 700 O-B9 stars with $uvby\beta$ photometry
currently available. The derived stellar physical parameters were used to
establish a homogeneous scale for the distances and extinction of light for
major apparent groups and layers of foreground and background stars in
Centaurus and study the interaction with the surrounding interstellar medium.
The distance to the entire Centaurus star-forming complex is revised and a
maximum of the OB-star distance distribution is found at 1.8$\pm$0.4 (r.m.s)
kpc. The massive star component of GSH 305+01-24 is identified at about 85-90 %
completeness up to 11.5-12 mag. The projected coincidence of the OB stars with
the shell and the similarities between the shell's morphology and the OB-star
distribution indicate a strong interaction of the stellar winds with the
superbubble material. We demonstrate that these stars contribute a sufficient
wind injection energy in order to explain the observed size and expansion
velocity of the supershell. The derived stellar ages suggest an age gradient
over the Coalsack Loop. A continuous star-formation might be taking place
within the shell with the youngest stars located at its periphery and the open
cluster NGC 4755 being the oldest. A layer of very young stars at 1 kpc is
detected and its connection to both GSH 305+01-24 and the foreground GSH
304-00-12 H I shells is investigated.


title:
Electronic States of Wires and Slabs of Topological Insulators: Quantum
  Hall Effects and Edge Transport

abstract:
  We develop a simple model of surface states for topological insulators,
developing matching relations for states on surfaces of different orientations.
The model allows one to write simple Dirac Hamiltonians for each surface, and
to determine how perturbations that couple to electron spin impact them. We
then study two specific realizations of such systems: quantum wires of
rectangular cross-section and a rectangular slab in a magnetic field. In the
former case we find a gap at zero energy due to the finite size of the system.
This can be removed by application of exchange fields on the top and bottom
surfaces, which lead to gapless chiral states appearing on the lateral
surfaces. In the presence of a magnetic field, we examine how Landau level
states on surfaces perpendicular to the field join onto confined states of the
lateral surfaces. We show that an imbalance in the number of states propagating
in each direction on the lateral surface is sufficient to stabilize a quantized
Hall effect if there are processes that equilibrate the distribution of current
among these channels.


title: M-Functionals of Multivariate Scatter

abstract:
  This survey provides a self-contained account of $M$-estimation of
multivariate scatter. In particular, we present new proofs for existence of the
underlying $M$-functionals and discuss their weak continuity and
differentiability. This is done in a rather general framework with
matrix-valued random variables. By doing so we reveal a connection between
Tyler's (1987) $M$-functional of scatter and the estimation of proportional
covariance matrices. Moreover, this general framework allows us to treat a new
class of scatter estimators, based on symmetrizations of arbitrary order.
Finally these results are applied to $M$-estimation of multivariate location
and scatter via multivariate $t$-distributions.


title:
A likelihood-based reconstruction algorithm for top-quark pairs and the
  KLFitter framework

abstract:
  A likelihood-based reconstruction algorithm for arbitrary event topologies is
introduced and, as an example, applied to the single-lepton decay mode of
top-quark pair production. The algorithm comes with several options which
further improve its performance, in particular the reconstruction efficiency,
i.e., the fraction of events for which the observed jets and leptons can be
correctly associated with the final-state particles of the corresponding event
topology. The performance is compared to that of well-established
reconstruction algorithms using a common framework for kinematic fitting. This
framework has a modular structure which describes the physics processes and
detector models independently. The implemented algorithms are generic and can
easily be ported from one experiment to another.


title:
Static correlation beyond the random phase approximation: Dissociating
  H2 with the Bethe-Salpeter equation and time-dependent GW

abstract:
  We investigate various approximations to the correlation energy of a H$_2$
molecule in the dissociation limit, where the ground state is poorly described
by a single Slater determinant. The correlation energies are derived from the
density response function and it is shown that response functions derived from
Hedin's equations (Random Phase Approximation (RPA), Time-dependent
Hartree-Fock (TDHF), Bethe-Salpeter equation (BSE), and Time-Dependent GW
(TDGW)) all reproduce the correct dissociation limit. We also show that the BSE
improves the correlation energies obtained within RPA and TDHF significantly
for intermediate binding distances. A Hubbard model for the dimer allow us to
obtain exact analytical results for the various approximations, which is
readily compared with the exact diagonalization of the model. Moreover, the
model is shown to reproduce all the qualitative results from the \textit{ab
initio} calculations and confirms that BSE greatly improves the RPA and TDHF
results despite the fact that the BSE excitation spectrum breaks down in the
dissociation limit. In contrast, Second Order Screened Exchange (SOSEX) gives a
poor description of the dissociation limit, which can be attributed to the fact
that it cannot be derived from an irreducible response function.


title: Astrophysical parameters of the peculiar X-ray transient IGR J11215-5952

abstract:
  The hard X-ray source IGR J11215-5952 is a peculiar transient, displaying
very short X-ray outbursts every 165 days. We obtained high-resolution spectra
of the optical counterpart, HD 306414, at different epochs, spanning a total of
three months, before and around the 2007 February outburst with the combined
aims of deriving its astrophysical parameters and searching for orbital
modulation. We fit model atmospheres generated with the fastwind code to the
spectrum. We also cross-correlated each individual spectrum to the best-fit
model to derive radial velocities. From its spectral features, we classify HD
306414 as B0.5 Ia. From the model fit, we find Teff = 24 700 K and log g = 2.7,
in good agreement with the morphological classification. Using the interstellar
lines in its spectrum, we estimate a distance to HD 306414 d > 7 kpc. Assuming
this distance, we derive R* = 40 Rsol and Mspect = 30 Msol (consistent, within
errors, with Mevol = 38 Msol). Radial velocity changes are not dominated by the
orbital motion, and we find an upper limit on the semi-amplitude for the
optical component Kopt < 11 +- 6 km/s. Large variations in the depth and shape
of photospheric lines suggest the presence of strong pulsations, which may be
the main cause of the radial velocity changes. Very significant variations,
uncorrelated with those of the photospheric lines are seen in the shape and
position of the Halpha emission feature around the time of the X-ray outburst,
but large excursions are also observed at other times. HD 306414 is a normal
B0.5 Ia supergiant. Its radial velocity curve is dominated by an effect that is
different from binary motion, and is most likely stellar pulsations. The data
available suggest that the X-ray outbursts are caused by the close passage of
the neutron star in a very eccentric orbit, perhaps leading to localised mass
outflow. (abridged).


title: Vulnerability and power on networks

abstract:
  Inspired by socio-political scenarios, like dictatorships, in which a
minority of people exercise control over a majority of weakly interconnected
individuals, we propose vulnerability and power measures defined on groups of
actors of networks. We establish an unexpected connection between network
vulnerability and graph regularizability. We use the Shapley value of coalition
games to introduce fresh notions of vulnerability and power at node level
defined in terms of the corresponding measures at group level. We investigate
the computational complexity of computing the defined measures, both at group
and node levels, and provide effective methods to quantify them. Finally we
test vulnerability and power on both artificial and real networks.


title: Analysis of higher spin black holes with spin-4 chemical potential

abstract:
  We consider the $AdS_{3}/CFT_{2}$ duality between certain coset WZW theories
at large central charge and Vasiliev 3D higher spin gravity with a single
complex field. On the gravity side, we discuss a higher spin black hole
solution with chemical potential coupled to the spin-4 charge. We compute the
perturbative expansion of the higher spin charges and of the partition function
at high order in the chemical potential. The result is obtained with its exact
dependence on the parameter $\lambda$ characterising the symmetry algebra
$\mbox{hs}[\lambda]$. The cases of $\lambda=0,1$ are successfully compared with
a CFT calculation. The special point $\lambda=\infty$, the
Bergshoeff-Blencowe-Stelle limit, is also solved in terms of the exact
generating function for the partition function. The thermodynamics of both the
spin-4 and the usual spin-3 black holes is studied in order to discuss the
$\lambda$ dependence of the BTZ critical temperature $T_{\rm BTZ}(\lambda)$. In
the spin-3 case, it is shown that $T_{\rm BTZ}(\lambda)$ converges for large
$\lambda$ to the critical point of the $\lambda=\infty$ known partition
function previously found by the authors. In the spin-4 black hole, the picture
is qualitatively similar and $T_{\rm BTZ}(\infty)$ is accurately determined by
various numerical methods.


title: A note on acyclic vertex-colorings

abstract:
  We prove that the acyclic chromatic number of a graph with maximum degree
$\Delta$ is less than $2.835\Delta^{4/3}+\Delta$. This improves the previous
upper bound, which was $50\Delta^{4/3}$. To do so, we draw inspiration from
works by Alon, McDiarmid and Reed and by Esperet and Parreau.


title:
Experimental Determination of the Antineutrino Spectrum of the Fission
  Products of $^{238}$U

abstract:
  An experiment was performed at the scientific neutron source FRM II in
Garching to determine the cumulative antineutrino spectrum of the fission
products of $^{238}$U. This was achieved by irradiating target foils of natural
uranium with a thermal and a fast neutron beam and recording the emitted
$\beta$-spectra with a gamma-suppressing electron-telescope. The obtained
$\beta$-spectrum of the fission products of $^{235}$U was normalized to the
data of the magnetic spectrometer BILL of $^{235}$U. This method strongly
reduces systematic errors in the $^{238}$U measurement. The $\beta$-spectrum of
$^{238}$U was converted into the corresponding antineutrino spectrum. The final
$\bar\nu_e$-spectrum is given in 250 keV bins in the range from 2.875 MeV to
7.625 MeV with an energy-dependent error of 3.5 % at 3 MeV, 7.6 % at 6 MeV and
$\gtrsim$ 14 % at energies $\gtrsim$ 7 MeV (68 % confidence level).
Furthermore, an energy-independent uncertainty of $\sim$ 3.3 % due to the
absolute normalization is added. Compared to the generally used summation
calculations, the obtained spectrum reveals a slight spectral distortion of
$\sim$ 10 % but returns the same value for the mean cross section per fission
for the inverse beta decay.


title: Playing Atari with Deep Reinforcement Learning

abstract:
  We present the first deep learning model to successfully learn control
policies directly from high-dimensional sensory input using reinforcement
learning. The model is a convolutional neural network, trained with a variant
of Q-learning, whose input is raw pixels and whose output is a value function
estimating future rewards. We apply our method to seven Atari 2600 games from
the Arcade Learning Environment, with no adjustment of the architecture or
learning algorithm. We find that it outperforms all previous approaches on six
of the games and surpasses a human expert on three of them.


title: Some Remarks on Non-Planar Diagrams

abstract:
  Two criteria for planarity of a Feynman diagram upon its propagators
(momentum flows) are presented. Instructive Mathematica programs that solve the
problem and examples are provided. A simple geometric argument is used to show
that while one can planarize non-planar graphs by embedding them on
higher-genus surfaces (in the example it is a torus), there is still a problem
with defining appropriate dual variables since the corresponding faces of the
graph are absorbed by torus generators.


title: Learning Transformations for Classification Forests

abstract:
  This work introduces a transformation-based learner model for classification
forests. The weak learner at each split node plays a crucial role in a
classification tree. We propose to optimize the splitting objective by learning
a linear transformation on subspaces using nuclear norm as the optimization
criteria. The learned linear transformation restores a low-rank structure for
data from the same class, and, at the same time, maximizes the separation
between different classes, thereby improving the performance of the split
function. Theoretical and experimental results support the proposed framework.


title: Heavy Quark Fragmenting Jet Functions

abstract:
  Heavy quark fragmenting jet functions describe the fragmentation of a parton
into a jet containing a heavy quark, carrying a fraction of the jet momentum.
They are two-scale objects, sensitive to the heavy quark mass, $m_Q$, and to a
jet resolution variable, $\tau_N$. We discuss how cross sections for heavy
flavor production at high transverse momentum can be expressed in terms of
heavy quark fragmenting jet functions, and how the properties of these
functions can be used to achieve a simultaneous resummation of logarithms of
the jet resolution variable, and logarithms of the quark mass. We calculate the
heavy quark fragmenting jet function $\mathcal G_Q^Q$ at $\mathcal
O(\alpha_s)$, and the gluon and light quark fragmenting jet functions into a
heavy quark, $\mathcal G_g^Q$ and $\mathcal G_l^Q$, at $\mathcal
O(\alpha_s^2)$. We verify that, in the limit in which the jet invariant mass is
much larger than $m_Q$, the logarithmic dependence of the fragmenting jet
functions on the quark mass is reproduced by the heavy quark fragmentation
functions. The fragmenting jet functions can thus be written as convolutions of
the fragmentation functions with the matching coefficients $\mathcal J_{i j}$,
which depend only on dynamics at the jet scale. We reproduce the known matching
coefficients $\mathcal J_{i j}$ at $\mathcal O(\alpha_s)$, and we obtain the
expressions of the coefficients $\mathcal J_{g Q}$ and $\mathcal J_{l Q}$ at
$\mathcal O(\alpha_s^2)$. Our calculation provides all the perturbative
ingredients for the simultaneous resummation of logarithms of $m_Q$ and
$\tau_N$.


title:
Dilepton Production in Transport Calculations and Coarse-Grained
  Dynamics

abstract:
  We present transport calculations with the Ultra-relativistic Quantum
Molecular Dynamics approach (UrQMD) for dilepton spectra at SIS energies. While
we obtain a good agreement with experiment for elementary reactions, in
heavy-ion collisions an excess in the invariant mass spectra is observed which
cannot be described by the model. As the pure transport calculations do not
include any in-medium effects and are limited to hadronic degrees of freedom,
we present an alternative approach that uses coarse-grained output from
transport calculations to determine thermal dilepton emission rates. For this
we apply the medium-modified $\rho$ spectral function by Eletsky et al. In a
first exemplary comparison to data from the NA60 experiment we find that the
coarse-graining approach gives reasonable results.


title:
Density functional theory based calculations of the transfer integral in
  a redox-active single molecule junction

abstract:
  There are various quantum chemical approaches for an ab initio description of
transfer integrals within the framework of Marcus theory in the context of
electron transfer reactions. In our article we aim to calculate transfer
integrals in redox-active single molecule junctions, where we focus on the
coherent tunneling limit with the metal leads taking the position of donor and
acceptor and the molecule acting as a transport mediating bridge. This setup
allows us to derive a conductance, which can be directly compared with recent
results from a non-equilibrium Green's function approach. Compared with purely
molecular systems we face additional challenges due to the metallic nature of
the leads, which rules out some of the common techniques, and due to their
periodicity, which requires {\bf k} space integration. We present three
different methods, all based on density functional theory, for calculating the
transfer integral under these constraints, which we benchmark on molecular test
systems from the relevant literature. We also discuss manybody effects and
apply all three techniques to a junction with a Ruthenium complex in different
oxidation states.


title: NNLO QCD corrections to dijet production at hadron colliders

abstract:
  In this talk we present the calculation of next-to-next-to-leading order
(NNLO) QCD corrections to dijet production and related observables at hadron
colliders in the purely gluonic channel. Results for this channel are obtained
keeping all orders of $N_C$ in the colour expansion. We show that the NNLO
correction significantly reduces the scale uncertainty compared to
next-to-leading order (NLO). We present the NNLO double-differential single jet
inclusive cross section where jets are reconstructed using the anti-$k_T$ jet
algorithm and show the dependence on the jet resolution parameter $R$.


title:
Temperature dependence of electrical conductivity and dilepton rates
  from hot quenched lattice QCD

abstract:
  We present new results on the continuum extrapolation of the vector current
correlation function in the deconfined phase for three temperatures close to
the critical temperature utilizing quenched clover improved Wilson fermions and
light quark masses. A systematic analysis on multiple lattice spacing allows to
perform the continuum limit of the correlation function and to extract spectral
properties in the continuum limit. These results provide constraints for the
electrical conductivity and the thermal dilepton rates in the quark gluon
plasma for the given temperature range. In addition results on the continuum
extrapolation at finite momenta related to thermal photon rates are presented.


title:
Accounting for selection effects in the BH-bulge relations: No evidence
  for cosmological evolution

abstract:
  The redshift evolution of the black hole - bulge relations is an essential
observational constraint for models of black hole - galaxy coevolution. In
addition to the observational challenges for these studies, conclusions are
complicated by the influence of selection effects. We demonstrate that there is
presently no statistical significant evidence for cosmological evolution in the
black hole-bulge relations, once these selection effects are taken into account
and corrected for. We present a fitting method, based on the bivariate
distribution of black hole mass and galaxy property, that accounts for the
selection function in the fitting and is therefore able to recover the
intrinsic black hole - bulge relation unbiased. While prior knowledge is
restricted to a minimum, we at least require knowledge of either the sample
selection function and the mass dependence of the active fraction, or the
spheroid distribution function and the intrinsic scatter in the black hole -
bulge relation. We employed our fitting routine to existing studies of the
black hole-bulge relation at z~1.5 and z~6, using our current best knowledge of
the distribution functions. There is no statistical significant evidence for
positive evolution in the MBH-M* ratio out to z~2. At z~6 the current
constraints are less strong, but we demonstrate that the large observed
apparent offset from the local black hole-bulge relation at z~6 is fully
consistent with no intrinsic offset. The method outlined here provides a tool
to obtain more reliable constraints on black hole - galaxy co-evolution in the
future.


title:
Acoustic resonance spectroscopy for the advanced undergraduate
  laboratory

abstract:
  We present a simple experiment that allows advanced undergraduates to learn
the principles and applications of spectroscopy. The technique, known as
acoustic resonance spectroscopy, is applied to study a vibrating rod. The setup
includes electromagnetic-acoustic transducers, an audio amplifier and a vector
network analyzer. Typical results of compressional, torsional and bending waves
are analyzed and compared with analytical results.


title:
Symmetries of the periodic Toda lattice, with an application to normal
  forms and perturbations of the lattice with Dirichlet boundary conditions

abstract:
  Symmetries of the periodic Toda lattice are expresssed in action-angle
coordinates and characterized in terms of the periodic and Dirichlet spectrum
of the associated Jacobi matrices. Using these symmetries, the phase space of
the lattice with Dirichlet boundary conditions is embedded into the phase space
of a higher-dimensional periodic lattice. As an application, we obtain a
Birkhoff normal form and a KAM theorem for the lattice with Dirichlet boundary
conditions.


title:
The evaporation residue in the fission state of Barium nuclei within
  relativistic mean-field theory

abstract:
  The evaporation residue of Barium isotopes are investigated in a microscopic
study using relativistic mean field theory. The investigation includes the
isotopes of Barium from the valley of stability to exotic proton-rich region.
The ground as well as neck configurations for these nuclei are generated from
their total nucleonic density distributions of the corresponding state. We have
estimated the constituents (number of nucleons) in the elongated neck region of
the fission state. We found the $\alpha$-particle as the constituent of neck of
Ba-isotopes, referred to as the evaporated residue in heavy-ion reaction
studies. A strong correlation between the neutron and proton is observed
throughout the isotopic chain.


title:
Impact of a four-zero Yukawa texture on $h\to \gamma \gamma$ and $\gamma
  Z$ in the framework of the Two Higgs Doublet Model Type III

abstract:
  We study the substantial enhancement, with respect to the corresponding
Standard Model rates, that can be obtained for the branching ratios of the
decay channels $h \to \gamma \gamma$ and $h\to \gamma Z$ within the framework
of the Two Higgs Doublet Model Type III, assuming a four-zero Yukawa texture
and a general Higgs potential. We show that these processes are very sensitive
to the flavor pattern entering the Yukawa texture and to the triple coupling
structure of the Higgs potential, both of which impact onto the aforementioned
decays. We can accommodate the parameters of the model in such a way to obtain
the $h \to \gamma \gamma$ rates reported by the Large Hadron Collider and at
the same time we get a $h\to \gamma Z$ fraction much larger than in the
Standard Model, indeed within experimental reach. We present some scenarios
where this phenomenology is realized for spectrum configurations that are
consistent with current constraints. We also discuss the possibility of
obtaining a light charged Higgs boson compatible with all such measurements,
thereby serving the purpose of providing a hallmark signal of the scenario
considered.


title: Maximal subgroups of multi-edge spinal groups

abstract:
  A multi-edge spinal group is a subgroup of the automorphism group of a
regular p-adic rooted tree, generated by one rooted automorphism and a finite
number of directed automorphisms sharing a common directing path. We prove that
torsion multi-edge spinal groups do not have maximal subgroups of infinite
index. This generalizes a result of Pervova for GGS-groups.


title: Large-Scale Structure and Gravitational Waves III: Tidal Effects

abstract:
  The leading locally observable effect of a long-wavelength metric
perturbation corresponds to a tidal field. We derive the tidal field induced by
scalar, vector, and tensor perturbations, and use second order perturbation
theory to calculate the effect on the locally measured small-scale density
fluctuations. For sub-horizon scalar perturbations, we recover the standard
perturbation theory result ($F_2$ kernel). For tensor modes of wavenumber
$k_L$, we find that effects persist for $k_L\tau \gg 1$, i.e. even long after
the gravitational wave has entered the horizon and redshifted away, i.e. it is
a "fossil" effect. We then use these results, combined with the "ruler
perturbations" of arXiv:1204.3625, to predict the observed distortion of the
small-scale matter correlation function induced by a long-wavelength tensor
mode. We also estimate the observed signal in the B mode of the cosmic shear
from a gravitational wave background, including both tidal (intrinsic
alignment) and projection (lensing) effects. The non-vanishing tidal effect in
the $k_L\tau \gg 1$ limit significantly increases the intrinsic alignment
contribution to shear B modes, especially at low redshifts $z \lesssim 2$.


title: Accelerated Share Repurchase: pricing and execution strategy

abstract:
  In this article, we consider the optimal execution problem associated to
accelerated share repurchase contracts. When firms want to repurchase their own
shares, they often enter such a contract with a bank. The bank buys the shares
for the firm and is paid the average market price over the execution period,
the length of the period being decided upon by the bank during the buying
process. Mathematically, the problem is new and related to both option pricing
(Asian and Bermudan options) and optimal execution. We provide a model, along
with associated numerical methods, to determine the optimal stopping time and
the optimal buying strategy of the bank.


title:
Probing the accelerating Universe with radio weak lensing in the JVLA
  Sky Survey

abstract:
  We outline the prospects for performing pioneering radio weak gravitational
lensing analyses using observations from a potential forthcoming JVLA Sky
Survey program. A large-scale survey with the JVLA can offer interesting and
unique opportunities for performing weak lensing studies in the radio band, a
field which has until now been the preserve of optical telescopes. In
particular, the JVLA has the capacity for large, deep radio surveys with
relatively high angular resolution, which are the key characteristics required
for a successful weak lensing study. We highlight the potential advantages and
unique aspects of performing weak lensing in the radio band. In particular, the
inclusion of continuum polarisation information can greatly reduce noise in
weak lensing reconstructions and can also remove the effects of intrinsic
galaxy alignments, the key astrophysical systematic effect that limits weak
lensing at all wavelengths. We identify a VLASS "deep fields" program (total
area ~10-20 square degs), to be conducted at L-band and with high-resolution
(A-array configuration), as the optimal survey strategy from the point of view
of weak lensing science. Such a survey will build on the unique strengths of
the JVLA and will remain unsurpassed in terms of its combination of resolution
and sensitivity until the advent of the Square Kilometre Array. We identify the
best fields on the JVLA-accessible sky from the point of view of overlapping
with existing deep optical and near infra-red data which will provide crucial
redshift information and facilitate a host of additional compelling
multi-wavelength science.


title: Internal Homs via extensions of dg functors

abstract:
  We provide a simple proof of the existence of internal Homs in the
localization of the category of dg categories with respect to all
quasi-equivalences and of some of their main properties such as the so-called
derived Morita theory. This was originally proved in a seminal paper by
To\"{e}n.


title: Further results on strong edge-colourings in outerplanar graphs

abstract:
  An edge-colouring is {\em strong} if every colour class is an induced
matching. In this work we give a formulae that determines either the optimal or
the optimal plus one strong chromatic index of bipartite outerplanar graphs.
Further, we give an improved upper bound for any outerplanar graph which is
close to optimal. All our proofs yield efficient algorithms to construct such
colourings.


title:
Probing the nature of $Y(4260)$ and $Z_c(3900)$ in the isospin violating
  process $Y(4260) \to J/\psi \eta \pi^0$

abstract:
  The isospin violation process $Y(4260) \to J/\psi \eta \pi^{0}$ is studied
assuming that $Y(4260)$ is a $D_{1} \bar{D}+c.c.$ hadronic molecule. In
association with the production of the $Z_c(3900)$, which is treated as a $D
\bar{D}^{*}+c.c.$ hadronic molecule, this process can help us distinguish their
molecular natures from other scenarios, since the incomplete cancellation
between the charged and neutral--meson loops, which are prominent in the
molecular picture only, produces a peak in the $e^+e^-\to Y(4260)\to
J/\psi\eta\pi^0$ cross section at the $D_{1} \bar{D}+c.c.$ threshold and a very
prominent peak in the $J/\psi \eta$ invariant mass spectrum in between the $D
\bar{D}^{*}+c.c.$ thresholds; the latter being much narrower than the
corresponding one in the isospin conserving channel, i.e. $J/\psi \pi^+
\pi^{-}$. The partial width of $Y(4260)\to J/\psi\eta\pi^0$ is about $4 \times
10^{-4}$ of that of $Y(4260)\to J/\psi\pi^+\pi^-$. The cross section of
$e^+e^-\to Y(4260)\to J/\psi\eta\pi^0$ at the $D_{1} \bar{D}+c.c.$ threshold is
about $0.05 \ \mathrm{pb}$ which is much larger than that produced by the
nearby resonances. These features are the direct consequences of the assumed
nature of these two states which might be accessible at the high-statistics
experiments such as BESIII and LHCb.


title: Maximum-likelihood fits to histograms for improved parameter estimation

abstract:
  Straightforward methods for adapting the familiar chi^2 statistic to
histograms of discrete events and other Poisson distributed data generally
yield biased estimates of the parameters of a model. The bias can be important
even when the total number of events is large. For the case of estimating a
microcalorimeter's energy resolution at 6 keV from the observed shape of the Mn
K-alpha fluorescence spectrum, a poor choice of chi^2 can lead to biases of at
least 10% in the estimated resolution when up to thousands of photons are
observed. The best remedy is a Poisson maximum-likelihood fit, through a simple
modification of the standard Levenberg-Marquardt algorithm for chi^2
minimization. Where the modification is not possible, another approach allows
iterative approximation of the maximum-likelihood fit.


title: Negative quantum capacitance in graphene nanoribbons with lateral gates

abstract:
  We present numerical simulations of the capacitive coupling between graphene
nanoribbons of various widths and gate electrodes in different configurations.
We compare the influence of lateral metallic or graphene side gate structures
on the overall back gate capacitive coupling. Most interestingly, we find a
complex interplay between quantum capacitance effects in the graphene
nanoribbon and the lateral graphene side gates, giving rise to an
unconventional negative quantum capacitance. The emerging non-linear capacitive
couplings are investigated in detail. The experimentally relevant relative
lever arm, the ratio between the coupling of the different gate structures, is
discussed.


title: On the Power Counting in Effective Field Theories

abstract:
  We discuss the systematics of power counting in general effective field
theories, focussing on those that are nonrenormalizable at leading order. As an
illuminating example we consider chiral perturbation theory gauged under the
electromagnetic $U(1)$ symmetry. This theory describes the low-energy
interactions of the octet of pseudo-Goldstone bosons in QCD with photons and
has been discussed extensively in the literature. Peculiarities of the standard
approach are pointed out and it is shown how these are resolved within our
scheme. The presentation follows closely our recent discussion of power
counting for the electroweak chiral Lagrangian. The systematics of the latter
is reviewed and shown to be consistent with the concept of chiral dimensions.
The results imply that naive dimensional analysis (NDA) is incomplete in
general effective field theories, while still reproducing the correct counting
in special cases.


title: Prediction and Dissipation in Biochemical Sensing

abstract:
  Cells sense and predict their environment via energy-dissipating pathways.
However, it is unclear whether dissipation helps or harms prediction. Here we
study dissipation and prediction for a minimal sensory module of receptors that
reversibly bind ligand. We find that the module performs short-term prediction
optimally when operating in an adiabatic regime where dissipation vanishes. In
contrast, beyond a critical forecast interval, prediction becomes most precise
in a regime of maximal dissipation, suggesting that dissipative sensing in
biological systems can serve to enhance prediction performance.


title: Graph properties, graph limits and entropy

abstract:
  We study the relation between the growth rate of a graph property and the
entropy of the graph limits that arise from graphs with that property. In
particular, for hereditary classes we obtain a new description of the colouring
number, which by well-known results describes the rate of growth.
  We study also random graphs and their entropies. We show, for example, that
if a hereditary property has a unique limiting graphon with maximal entropy,
then a random graph with this property, selected uniformly at random from all
such graphs with a given order, converges to this maximizing graphon as the
order tends to infinity.


title: Duality and syzygies for semimodules over numerical semigroups

abstract:
  Let $\Gamma=\langle \alpha, \beta \rangle$ be a numerical semigroup. In this
article we consider the dual $\Delta^*$ of a $\Gamma$-semimodule $\Delta$; in
particular we deduce a formula that expresses the minimal set of generators of
$\Delta^*$ in terms of the generators of $\Delta$. As applications we compute
the minimal graded free resolution of a graded
$\mathbb{F}[t^{\alpha},t^{\beta}]$-submodule of $\mathbb{F}[t]$, and we
investigate the structure of the selfdual $\Gamma$-semimodules, leading to a
new way of counting them.


title:
Deconfinement transition in two-flavour lattice QCD with dynamical
  overlap fermions in an external magnetic field

abstract:
  We study the influence of an external magnetic field on the deconfinement
transition in two-flavour lattice QCD with physical quark charges. We use
dynamical overlap fermions without any approximation such as fixed topology and
perform simulations on a $16^3 \times 6$ lattice and at a pion mass around
$500MeV$. The pion mass (as well as the lattice spacing) was determined in
independent runs on $12^3 \times 24$ lattices. We consider two temperatures,
one of which is close to the deconfinement transition and one which is above.
Within our limited statistics the dependence of the Polyakov loop and chiral
condensate on the magnetic field supports the "inverse magnetic catalysis"
scenario in which the transition temperature decreases as the field strength
grows for temperature not to far above the critical temperature.


title:
On the microscopic mechanism of ion-extraction of a gridded ion
  propulsion thruster

abstract:
  The following paper includes a physical microscopic particle-description of
the phenomena and mechanisms that lead to the extraction of ions with the aim
to generate thrust. This theoretical treatise arose from the intention to
visualize the behavior of the involved particles under effect of the involved
electrical fields. By this way, an underlying basis for experimental
investigations of the work of an ion thruster should be formed. So a foundation
was created, which explains the ion extracting and so thrust generating
function of an ion thruster. The theoretical work was related to the
Radio-frequency Ion Thruster (RIT). But the model worked out can be generalized
for all thruster types that use electrostatic fields to extract positively
charged ions.


title:
Secondary CMB anisotropies from bulk motions in the presence of
  stochastic magnetic fields

abstract:
  Bulk motions of electrons along the line of sight induce secondary
temperature fluctuations in the post-decoupling, reionized universe. In the
presence of a magnetic field not only the scalar mode but also the vector mode
act as a source for the bulk motion. The resulting angular power spectrum of
temperature anisotropies of the cosmic microwave background is calculated
assuming a simple model of reionization.Contributions from the standard
adiabatic, curvature mode and a non helical magnetic field are included. The
contribution due to magnetic fields with field strengths of order nG and
negative magnetic spectral indices becomes important for multipoles larger than
$\ell \sim 10^4$.


title: GRB 130606A within a sub-DLA at redshift 5.91

abstract:
  Events such as GRB130606A at z=5.91, offer an exciting new window into
pre-galactic metal enrichment in these very high redshift host galaxies. We
study the environment and host galaxy of GRB 130606A, a high-z event, in the
context of a high redshift population of GRBs. We have obtained multiwavelength
observations from radio to gamma-ray, concentrating particularly on the X-ray
evolution as well as the optical photometric and spectroscopic data analysis.
With an initial Lorentz bulk factor in the range \Gamma_0 ~ 65-220, the X-ray
afterglow evolution can be explained by a time-dependent photoionization of the
local circumburst medium, within a compact and dense environment. The host
galaxy is a sub-DLA (log N (HI) = 19.85+/-0.15), with a metallicity content in
the range from ~1/7 to ~1/60 of solar. Highly ionized species (N V and Si IV)
are also detected. This is the second highest redshift burst with a measured
GRB-DLA metallicity and only the third GRB absorber with sub-DLA HI column
density. GRB ' lighthouses' therefore offer enormous potential as backlighting
sources to probe the ionization and metal enrichment state of the IGM at very
high redshifts for the chemical signature of the first generation of stars.


title: Tunneling in heavy-fermion junctions

abstract:
  In this paper I briefly overview recent theoretical and experimental advances
in understanding of tunneling processes between normal metals and metals
containing electrons which occupy partially filled f-orbitals. In heavy-fermion
materials the effective mass of the quasiparticles far exceeds the bare
electron mass due to strong hybridization between conduction and f-orbital
states. Kondo lattices form a class of heavy-fermion systems in which an
average occupation number of f-electron states is close to an integer.
Therefore, the tunneling into a Kondo lattice necessarily involves co-tunneling
process of a tip electron into an f-electron state of a Kondo lattice. This
co-tunneling process is manifested in the Fano-lineshape of differential
conductance as a function of an applied voltage, which has been routinely
observed in recent experiments on various Kondo lattice systems. To illustrate
these ideas, I discuss the problem of the tunneling junction when the single
particle states in the tip are also a product of hybridization between
conduction and f-states, i.e. tunneling between two heavy-fermion materials.


title: Ferroelectric domain triggers the charge modulation in semiconductors

abstract:
  We consider a typical heterostructure domain patterned ferroelectric
film/ultra thin dielectric layer/ semiconductor, where the semiconductor can be
an electrolyte, paraelectric or multi layered graphene. Unexpectedly we have
found that the space charge modulation profile and amplitude in the
semiconductor, that screens the spontaneous polarization of a 180-degree domain
structure of ferroelectric, depends on the domain structure period, dielectric
layer thickness and semiconductor screening radius in a rather non-trivial
nonlinear way. Multiple size effects appearance and manifestation are defined
by the relationship between these three parameters. In addition, we show that
the concept of effective gap can be introduced in a simple way only for a
single domain limit. Obtained analytical results open the way for understanding
of current AFM maps of contaminated ferroelectric surfaces in ambient
atmosphere as well as explore the possibilities of conductivity control in
ultra-thin semiconductor layers.


title: Fixed points of the EM algorithm and nonnegative rank boundaries

abstract:
  Mixtures of $r$ independent distributions for two discrete random variables
can be represented by matrices of nonnegative rank $r$. Likelihood inference
for the model of such joint distributions leads to problems in real algebraic
geometry that are addressed here for the first time. We characterize the set of
fixed points of the Expectation-Maximization algorithm, and we study the
boundary of the space of matrices with nonnegative rank at most $3$. Both of
these sets correspond to algebraic varieties with many irreducible components.


title: The Oxygen core inside the Magnesium isotopes

abstract:
  We have studied the ground state bulk properties of magnesium isotopes using
axially symmetric relativistic mean field formalism. The BCS pairing approach
is employed to take care of the pairing correlation for the open shell nuclei.
The contour plot of the nucleons distribution are analyzed at various parts of
the nucleus, where clusters are located. The presence of an $^{16}$O core along
bubble like $\alpha$-particle(s) and few {\it nucleons} are found in the Mg
isotopes.


title: On the nature of the new group LB1

abstract:
  The new local group LB1 introduced previously will be studied in detail,
depicting its unique nature that makes it a new group in fundamental physics.
It will be made clear that even though most of its elements are Lorentz
transformations, one unique discrete transformation not present in the Lorentz
groups, is making this group into a new group. In fact there will be two kinds
of discrete transformations, one a Lorentz transformation, the other not. It is
these discrete transformations that allow for an isomorphism between the group
SO(2) and LB1. An isomorphism between the compact group SO(2) and the
non-compact group SO(1,1) plus two kinds of discrete transformations that make
up the new group LB1.


title:
Model-dependent estimate on the connection between fast radio bursts and
  ultra-high energy cosmic rays

abstract:
  The existence of fast radio bursts (FRBs), a new type of extragalatic
transients, has been established recently and quite a few models have been
proposed. In this work we discuss the possible connection between the FRB
sources and ultra-high energy ($>10^{18}$ eV) cosmic rays. We show that in the
blitzar model and the model of merging binary neutron stars, the huge energy
release of each FRB central engine together with the rather high rate of FRBs,
the accelerated EeV cosmic rays may contribute significantly to the observed
ones. In other FRB models including for example the merger of double white
dwarfs and the energetic magnetar radio flares, no significant EeV cosmic ray
is expected. We also suggest that the mergers of double neutron stars, even if
they are irrelevant to FRBs, may play a non-ignorable role in producing EeV
cosmic ray protons if supramassive neutron stars were formed in a good fraction
of mergers and the merger rate is $\gtrsim 10^{3}~{\rm yr^{-1}~ Gpc^{-3}}$.
Such a possibility will be unambiguously tested in the era of gravitational
wave astronomy.


title: Exploring Multi-Modal Distributions with Nested Sampling

abstract:
  In performing a Bayesian analysis, two difficult problems often emerge.
First, in estimating the parameters of some model for the data, the resulting
posterior distribution may be multi-modal or exhibit pronounced (curving)
degeneracies. Secondly, in selecting between a set of competing models,
calculation of the Bayesian evidence for each model is computationally
expensive using existing methods such as thermodynamic integration. Nested
Sampling is a Monte Carlo method targeted at the efficient calculation of the
evidence, but also produces posterior inferences as a by-product and therefore
provides means to carry out parameter estimation as well as model selection.
The main challenge in implementing Nested Sampling is to sample from a
constrained probability distribution. One possible solution to this problem is
provided by the Galilean Monte Carlo (GMC) algorithm. We show results of
applying Nested Sampling with GMC to some problems which have proven very
difficult for standard Markov Chain Monte Carlo (MCMC) and down-hill methods,
due to the presence of large number of local minima and/or pronounced (curving)
degeneracies between the parameters. We also discuss the use of Nested Sampling
with GMC in Bayesian object detection problems, which are inherently
multi-modal and require the evaluation of Bayesian evidence for distinguishing
between true and spurious detections.


title: Simplified flexibility analysis of proteins

abstract:
  A simple way to get insights about the possible functional motions of a
protein is to perform a normal mode analysis (NMA). Indeed, it has been shown
that low-frequency modes thus obtained are often closely related to domain
motions involved in protein function. Moreover, because protein low-frequency
modes are known to be robust, NMA can be performed using coarse-grained models.
As a consequence, it can be done for large ensembles of conformations as well
as for large systems, like the ribosome, whole virus capsids, etc.
Unexpectedly, on the high-frequency side, modes obtained with cutoff-based
coarse-grained models also seem able to provide useful insights on protein
dynamical properties.


title:
Improved Hubble Space Telescope Proper Motions for Tycho-G and Other
  Stars in the Remnant of Tycho's Supernova 1572

abstract:
  With archival and new Hubble Space Telescope observations we have refined the
space-velocity measurements of the stars in the central region of the remnant
of Tycho's supernova (SN) 1572, one of the historical Galactic Type Ia
supernova remnants (SNRs). We derived a proper motion for Tycho-G of
(mu_RA_cos_dec;mu_dec)=(-2.63;-3.98)+/-(0.06;0.04)[formal
errors]+/-(0.18;0.10)[expected errors] mas/yr. We also reconstruct the binary
orbit that Tycho-G should have followed if it were the surviving companion of
SN 1572. We redetermine the Ni abundance of this star and compare it with new
abundance data from stars of the Galactic disk, finding that [Ni/Fe] is about
1.7 sigma above the Galactic trend. From the high velocity (v_b = -50+/-14
km/s) of Tycho-G perpendicular to the Galactic plane, its metallicity, and its
Ni excess, we find the probability of its being a chance interloper to be P <
0.00037 at most. The projected rotational velocity of the star should be below
current observational limits. The projected position of Tycho-G is, within the
uncertainties, consistent with the centroid of the X-ray emission of Tycho's
SNR; moreover, its brightness is generally consistent with the post-explosion
evolution of the luminosity of a SN companion. Among the other 23 stars having
V<22 mag and located within 42 arcsec from the X-ray centroid, only 4 are at
distances compatible with that of the SNR, and none of them shows any
peculiarity. Therefore, if even Tycho-G is not the surviving companion of SN
1572, the absence of other viable candidates does favor the merging of two
white dwarfs as the producer of the SN.


title:
Recursive Robust PCA or Recursive Sparse Recovery in Large but
  Structured Noise (parts 1 and 2 combined)

abstract:
  This work studies the recursive robust principal components analysis (PCA)
problem. If the outlier is the signal-of-interest, this problem can be
interpreted as one of recursively recovering a time sequence of sparse vectors,
$S_t$, in the presence of large but structured noise, $L_t$. The structure that
we assume on $L_t$ is that $L_t$ is dense and lies in a low dimensional
subspace that is either fixed or changes "slowly enough". A key application
where this problem occurs is in video surveillance where the goal is to
separate a slowly changing background ($L_t$) from moving foreground objects
($S_t$) on-the-fly. To solve the above problem, in recent work, we introduced a
novel solution called Recursive Projected CS (ReProCS). In this work we develop
a simple modification of the original ReProCS idea and analyze it. This
modification assumes knowledge of a subspace change model on the $L_t$'s. Under
mild assumptions and a denseness assumption on the unestimated part of the
subspace of $L_t$ at various times, we show that, with high probability
(w.h.p.), the proposed approach can exactly recover the support set of $S_t$ at
all times; and the reconstruction errors of both $S_t$ and $L_t$ are upper
bounded by a time-invariant and small value. In simulation experiments, we
observe that the last assumption holds as long as there is some support change
of $S_t$ every few frames.


title:
Condensation in stochastic mass transport models: beyond the zero-range
  process

abstract:
  We consider an extension of the zero-range process to the case where the hop
rate depends on the state of both departure and arrival sites. We recover the
misanthrope and the target process as special cases for which the probability
of the steady state factorizes over sites. We discuss conditions which lead to
the condensation of particles and show that although two different hop rates
can lead to the same steady state, they do so with sharply contrasting
dynamics. The first case resembles the dynamics of the zero-range process,
whereas the second case, in which the hop rate increases with the occupation
number of both sites, is similar to instantaneous gelation models. This new
"explosive" condensation reveals surprisingly rich behaviour, in which the
process of condensate's formation goes through a series of collisions between
clusters of particles moving through the system at increasing speed. We perform
a detailed numerical and analytical study of the dynamics of condensation: we
find the speed of the moving clusters, their scattering amplitude, and their
growth time. We finally show that the time to reach steady state decreases with
the size of the system.


title:
The bright end of the galaxy luminosity function at z ~ 7: before the
  onset of mass quenching?

abstract:
  We present the results of a new search for bright star-forming galaxies at z
~ 7 within the UltraVISTA DR2 and UKIDSS UDS DR10 data, which together provide
1.65 sq deg of near-infrared imaging with overlapping optical and Spitzer data.
Using a full photo-z analysis to identify high-z galaxies and reject
contaminants, we have selected a sample of 34 luminous (-22.7 < M_UV < -21.2)
galaxies with 6.5 < z < 7.5. Crucially, the deeper imaging provided by
UltraVISTA DR2 confirms all of the robust objects previously uncovered by
Bowler et al. (2012), validating our selection technique. Our sample includes
the most massive galaxies known at z ~ 7, with M_* ~ 10^{10} M_sun, and the
majority are resolved, consistent with larger sizes (r_{1/2} ~ 1 - 1.5 kpc)
than displayed by less massive galaxies. From our final sample, we determine
the form of the bright end of the rest-frame UV galaxy luminosity function (LF)
at z ~ 7, providing strong evidence that the bright end of the z = 7 LF does
not decline as steeply as predicted by the Schechter function fitted to fainter
data. We consider carefully, and exclude the possibility that this is due to
either gravitational lensing, or significant contamination of our galaxy sample
by AGN. Rather, our results favour a double power-law form for the galaxy LF at
high z, or, more interestingly, a LF which simply follows the form of the
dark-matter halo mass function at bright magnitudes. This suggests that the
physical mechanism which inhibits star-formation activity in massive galaxies
(i.e. AGN feedback or some other form of `mass quenching') has yet to impact on
the observable galaxy LF at z ~ 7, a conclusion supported by the estimated
masses of our brightest galaxies which have only just reached a mass comparable
to the critical `quenching mass' of M_* = 10 ^{10.2} M_sun derived from studies
of the mass function of star-forming galaxies at lower z.


title: Self-dual String and Higher Instanton Solutions

abstract:
  We present and discuss explicit solutions to the non-abelian self-dual string
equation as well as to the non-abelian self-duality equation in six dimensions.
These solutions are generalizations of the 't Hooft-Polyakov monopole and the
BPST instanton to higher gauge theory. We expect that these solutions are
relevant to the effective description of M2- and M5-branes.


title:
Pulsed force sequences for fast phase-insensitive quantum gates in
  trapped ions

abstract:
  We show how to create quantum gates of arbitrary speed between trapped ions,
using a laser walking wave, with complete insensitivity to drift of the optical
phase, and requiring cooling only to the Lamb-Dicke regime. We present pulse
sequences that satisfy the requirements and are easy to produce in the
laboratory.


title: Ising Model from Intertwiners

abstract:
  Spin networks appear in a number of areas, for instance in lattice gauge
theories and in quantum gravity. They describe the contraction of intertwiners
according to the underlying network. We show that a certain generating function
of intertwiner contractions leads to the partition function of the 2d Ising
model. This implies that the intertwiner model possesses a second order phase
transition, thus leading to a continuum limit with propagating degrees of
freedom.

categories: gr-qc cond-mat.stat-mech hep-th math-ph math.MP


title: On the first continuous $L^2$-cohomology of free group factors

abstract:
  We prove that the first continuous $L^2$-cohomology of free group factors
vanishes. This answers a question by Andreas Thom regarding continuity
properties of free difference quotients and shows that one can not distinguish
free group factors by means of first continuous $L^2$-Betti number.


title:
Structure and kinetics of chemically cross-linked protein gels from
  small-angle X-ray scattering

abstract:
  Glutaraldehyde (GA) reacts with amino groups in proteins, forming
intermolecular cross-links that, at sufficiently high protein concentration,
can transform a protein solution into a gel. Although GA has been used as a
cross-linking reagent for decades, neither the cross-linking chemistry nor the
microstructure of the resulting protein gel have been clearly established. Here
we use small-angle X-ray scattering (SAXS) to characterise the microstructure
and structural kinetics of gels formed by cross-linking of pancreatic trypsin
inhibitor, myoglobin or intestinal fatty acid-binding protein. By comparing the
scattering from gels and dilute solutions, we extract the structure factor and
the pair correlation function of the gels. The protein gels are spatially
heterogeneous, with dense clusters linked by sparse networks. Within the
clusters, adjacent protein molecules are almost in contact, but the protein
concentration in the cluster is much lower than in a crystal. At the $\sim$1 nm
SAXS resolution, the native protein structure is unaffected by cross-linking.
The cluster radius is in the range 10 - 50 nm, with the cluster size determined
mainly by the availability of lysine amino groups on the protein surface. The
development of structure in the gel, on time scales from minutes to hours,
appears to obey first-order kinetics. Cross-linking is slower at acidic pH,
where the population of amino groups in the reactive deprotonated form is low.
These results support the use of cross-linked protein gels in NMR studies of
protein dynamics and for modeling NMR relaxation in biological tissue.


title:
Wavelet-based cascade model for intermittent structure in terrestrial
  environments

abstract:
  A wavelet-like model for distributions of objects in natural and man-made
terrestrial environments is developed. The model is constructed in a
self-similar fashion, with the sizes, amplitudes, and numbers of objects
occurring at a constant ratios between parent and offspring objects. The
objects are randomly distributed in space according to a Poisson process.
Fractal supports and a cascade model are used to organize objects
intermittently in space. In its basic form, the model is for continuously
varying random fields, although a level-cut is introduced to model two-phase
random media. The report begins with a description of relevant concepts from
fractal theory, and then progresses through static (time-invariant),
steady-state, and non-steady models. The results can be applied to such diverse
phenomena as turbulence, geologic distributions, urban buildings, vegetation,
and arctic ice floes. The model can be used as a basis for synthesizing
realistic terrestrial scenes, and for predicting the performance of sensing and
communication systems in operating environments with complex, intermittent
distributions of scattering objects.


title: Zero-Shot Learning by Convex Combination of Semantic Embeddings

abstract:
  Several recent publications have proposed methods for mapping images into
continuous semantic embedding spaces. In some cases the embedding space is
trained jointly with the image transformation. In other cases the semantic
embedding space is established by an independent natural language processing
task, and then the image transformation into that space is learned in a second
stage. Proponents of these image embedding systems have stressed their
advantages over the traditional \nway{} classification framing of image
understanding, particularly in terms of the promise for zero-shot learning --
the ability to correctly annotate images of previously unseen object
categories. In this paper, we propose a simple method for constructing an image
embedding system from any existing \nway{} image classifier and a semantic word
embedding model, which contains the $\n$ class labels in its vocabulary. Our
method maps images into the semantic embedding space via convex combination of
the class label embedding vectors, and requires no additional training. We show
that this simple and direct method confers many of the advantages associated
with more complex image embedding schemes, and indeed outperforms state of the
art methods on the ImageNet zero-shot learning task.


title: The Effect of Carbon Monoxide on Planetary Haze Formation

abstract:
  Organic haze plays a key role in many planetary processes ranging from
influencing the radiation budget of an atmosphere to serving as a source of
prebiotic molecules on the surface. Numerous experiments have investigated the
aerosols produced by exposing mixtures of N$_{2}$/CH$_{4}$ to a variety of
energy sources. However, many N$_{2}$/CH$_{4}$ atmospheres in both our solar
system and extrasolar planetary systems also contain CO. We have conducted a
series of atmosphere simulation experiments to investigate the effect of CO on
formation and particle size of planetary haze analogues for a range of CO
mixing ratios using two different energy sources, spark discharge and UV. We
find that CO strongly affects both number density and particle size of the
aerosols produced in our experiments and indicates that CO may play an
important, previously unexplored, role in aerosol chemistry in planetary
atmospheres.


title:
On the approximation of convolutions by accompanying laws in the scheme
  of series

abstract:
  The problem of the approximation of convolutions by accompanying laws in the
scheme of series satisfying the infinitesimality condition is considered. It is
shown that the quality of approximation depends essentially on the choice of
centering constants.