title: Stochastic Mechanistic Interaction

abstract:
  We propose a fully probabilistic formulation of the notion of mechanistic
interaction (interaction in some fundamental mechanistic sense) between the
effects of putative (possibly continuous) causal factors A and B on a binary
outcome variable Y indicating 'survival' vs 'failure'. We define mechanistic
interaction in terms of departure from a generalized 'noisy OR' model, under
which the multiplicative causal effect of A (resp., B) on the probability of
failure cannot be enhanced by manipulating B (resp., A). We present conditions
under which mechanistic interaction in the above sense can be assessed via
simple tests on excess risk or superadditivity, in a possibly retrospective
regime of observation. These conditions are defined in terms of generalized
conditional independence relationships (generalised because they may involve
non-stochastic 'regime indicators') that can often be checked on a graphical
representation of the problem. Inference about mechanistic interaction between
direct, or path-specific, causal effects can be accommodated in the proposed
framework. The method is illustrated with the aid of a study in experimental
psychology.


title: An extension of a Theorem of V. \v{S}ver\'ak to variable exponent spaces

abstract:
  In 1993, V. \v{S}ver\'ak proved that if a sequence of uniformly bounded
domains $\Omega_n\subset {\mathbb R}^2$ such that $\Omega_n\to \Omega$ in the
sense of the Hausdorff complementary topology, verify that the number of
connected components of its complements are bounded, then the solutions of the
Dirichlet problem for the Laplacian with source $f\in L^2({\mathbb R}^2)$
converges to the solution of the limit domain with same source. In this paper,
we extend \v{S}ver\'ak result to variable exponent spaces.


title: Detection of Partially Visible Objects

abstract:
  An "elephant in the room" for most current object detection and localization
methods is the lack of explicit modelling of partial visibility due to
occlusion by other objects or truncation by the image boundary. Based on a
sliding window approach, we propose a detection method which explicitly models
partial visibility by treating it as a latent variable. A novel non-maximum
suppression scheme is proposed which takes into account the inferred partial
visibility of objects while providing a globally optimal solution. The method
gives more detailed scene interpretations than conventional detectors in that
we are able to identify the visible parts of an object. We report improved
average precision on the PASCAL VOC 2010 dataset compared to a baseline
detector.


title: Entanglement and Quantum Error Correction with Superconducting Qubits

abstract:
  A quantum computer will use the properties of quantum physics to solve
certain computational problems much faster than otherwise possible. One
promising potential implementation is to use superconducting quantum bits in
the circuit quantum electrodynamics (cQED) architecture. There, the low energy
states of a nonlinear electronic oscillator are isolated and addressed as a
qubit. These qubits are capacitively coupled to the modes of a
microwave-frequency transmission line resonator which serves as a quantum
communication bus. Microwave electrical pulses are applied to the resonator to
manipulate or measure the qubit state. State control is calibrated using
diagnostic sequences that expose systematic errors. Hybridization of the
resonator with the qubit gives it a nonlinear response when driven strongly,
useful for amplifying the measurement signal to enhance accuracy. Qubits
coupled to the same bus may coherently interact with one another via the
exchange of virtual photons. A two-qubit conditional phase gate mediated by
this interaction can deterministically entangle its targets, and is used to
generate two-qubit Bell states and three-qubit GHZ states. These three-qubit
states are of particular interest because they redundantly encode quantum
information. They are the basis of the quantum repetition code prototypical of
more sophisticated schemes required for quantum computation. Using a
three-qubit Toffoli gate, this code is demonstrated to autonomously correct
either bit- or phase-flip errors. Despite observing the expected behavior, the
overall fidelity is low because of decoherence. A superior implementation of
cQED replaces the transmission-line resonator with a three-dimensional box
mode, increasing lifetimes by an order of magnitude. In-situ qubit frequency
control is enabled with control lines, which are used to fully characterize and
control the system Hamiltonian.


title: Data Assimilation by Conditioning on Future Observations

abstract:
  Conventional recursive filtering approaches, designed for quantifying the
state of an evolving uncertain dynamical system with intermittent observations,
use a sequence of (i) an uncertainty propagation step followed by (ii) a step
where the associated data is assimilated using Bayes' rule. In this paper we
switch the order of the steps to: (i) one step ahead data assimilation followed
by (ii) uncertainty propagation. This route leads to a class of filtering
algorithms named \emph{smoothing filters}. For a system driven by random noise,
our proposed methods require the probability distribution of the driving noise
after the assimilation to be biased by a nonzero mean. The system noise,
conditioned on future observations, in turn pushes forward the filtering
solution in time closer to the true state and indeed helps to find a more
accurate approximate solution for the state estimation problem.


title: Hamamatsu R1584 PMT Modifications

abstract:
  Four Hamamatsu H6528 Photomultiplier Tube (PMT) assemblies were purchased by
the University of Regina, to be used on the SHMS Heavy Gas Cherenkov detector.
Despite the excellent gain, the H6528 signal output has two disturbing
characteristics: discharges and ringing tails. In this report, we offer
solutions to overcome these issues.


title: Negative area compressibility in silver(I) tricyanomethanide

abstract:
  The molecular framework Ag(tcm) (tcm$^-$ = tricyanomethanide) expands
continuously in two orthogonal directions under hydrostatic compression. The
first of its kind, this negative area compressibility behaviour arises from the
flattening of honeycomb-like layers during rapid pressure-driven collapse of
the interlayer separation.


title: Outer Billiards on Regular Polygons

abstract:
  In 1973, J. Moser proposed that his Twist Theorem could be used to show that
orbits of the outer billiards map on a sufficiently smooth closed curve were
always bounded. Five years later Moser asked the same question for a convex
polygon. In 1987 F. Vivaldi and A. Shaidenko showed that all orbits for a
regular polygon must be bounded. R. Schwartz recently showed that a
quadrilateral known as a Penrose Kite has unbounded orbits and he proposed that
'most' convex polygons support unbounded orbits.
  Except for a few special cases, very little is known about the dynamics of
the outer billiards map on regular polygons. In this paper we present a unified
approach to the analysis of regular polygons - using the canonical 'resonances'
which are shared by all regular N-gons. In the case of the regular pentagon and
regular octagon these resonances exist on all scales and the fractal structure
is well documented, but these are the only non-trivial cases that have been
analyzed. We present a partial analysis of the regular heptagon, but the
limiting structure is poorly understood and this does not bode well for the
remaining regular polygons. The minimal polynomial for the vertices of a
regular N-gon has degree Phi(N)/2 where Phi is the Euler totient function, so N
= 5, 7 and 11 are respectively quadratic, cubic and quintic. In the words of R.
Schwartz, "A case such as N = 11 seems beyond the reach of current technology."
  Some of the graphics have embedded high-resolution versions so this file is
about 39Mb in size. This file and a smaller version can be downloaded at
dynamicsofpolygons.org. Just click on PDFs.
  This paper is dedicated to the memory of Eugene Gutkin (1946-2013) who made
fundamental contributions to both inner and outer billiards.


title:
On the Mechanism of Laminar-turbulent Transition and the Origin of the
  Critical Reynolds Number

abstract:
  A theoretical mechanism of laminar-turbulent transition originated from the
deceleration of fluid streams on the walls of the channel or pipe is proposed.
For Poiseuille flow an analytical expression relating the critical Reynolds
number with the degree of disturbance of the flow is derived.


title: Hypothesis testing by convex optimization

abstract:
  We discuss a general approach to handling "multiple hypotheses" testing in
the case when a particular hypothesis states that the vector of parameters
identifying the distribution of observations belongs to a convex compact set
associated with the hypothesis. With our approach, this problem reduces to
testing the hypotheses pairwise. Our central result is a test for a pair of
hypotheses of the outlined type which, under appropriate assumptions, is
provably nearly optimal. The test is yielded by a solution to a convex
programming problem, so that our construction admits computationally efficient
implementation. We further demonstrate that our assumptions are satisfied in
several important and interesting applications. Finally, we show how our
approach can be applied to a rather general detection problem encompassing
several classical statistical settings such as detection of abrupt signal
changes, cusp detection and multi-sensor detection.


title: Line geometry and electromagnetism II: wave motion

abstract:
  The fundamental role of line geometry in the study of wave motion is first
introduced in the general context by way of the tangent planes to the
instantaneous wave surfaces, in which it is first observed that the possible
frequency-wave number 1-forms are typically constrained by a dispersion law
that is derived from a constitutive law by way of the field equations. After a
general review of the basic concepts that relate to quadratic line complexes,
these geometric notions are applied to the study of electromagnetic waves, in
particular.


title:
The Dirichlet and Neumann and Dirichlet-to-Neumann problems in
  quadrature, double quadrature, and non-quadrature domains

abstract:
  We demonstrate that solving the classical problems mentioned in the title on
quadrature domains when the given boundary data is rational is as simple as the
method of partial fractions. A by-product of our considerations will be a
simple proof that the Dirichlet-to-Neumann map on a double quadrature domain
sends rational functions on the boundary to rational functions on the boundary.
The results extend to more general domains if rational functions are replaced
by the class of functions on the boundary that extend meromorphically to the
double.


title: Generalized phase transitions in Lovelock gravity

abstract:
  We investigate a novel mechanism for phase transitions that is a distinctive
feature of higher-curvature gravity theories. For definiteness, we bound
ourselves to the case of Lovelock gravities. These theories are known to have
several branches of asymptotically AdS solutions. Here, extending our previous
work, we show that phase transitions among some of these branches are driven by
a thermalon configuration: a bubble separating two regions of different
effective cosmological constants, generically hosting a black hole in the
interior. Above some critical temperature, this thermalon configuration is
preferred with respect to the finite-temperature AdS space, triggering a
sophisticated version of the Hawking-Page transition. After being created, the
unstable bubble configuration can in general dynamically change the asymptotic
cosmological constant. While this phenomenon already occurs in the case of a
gravity action with square curvature terms, we point out that in the case of
Lovelock theory with cubic (and higher) terms new effects appear. For instance,
the theory may admit more than one type of bubble and branches that are in
principle free of pathologies may also decay through the thermalon mechanism.
We also find ranges of the gravitational couplings for which the theory becomes
sick. These add up to previously found restrictions to impose tighter
constraints on higher-curvature gravities. The results of this paper point to
an intricate phase diagram which might accommodate similarly rich behavior in
the dual CFT side.


title:
Vertical beam size measurement in the CESR-TA $e^+e^-$ storage ring
  using x-rays from synchrotron radiation

abstract:
  We describe the construction and operation of an x-ray beam size monitor
(xBSM), a device measuring $e^+$ and $e^-$ beam sizes in the CESR-TA storage
ring using synchrotron radiation. The device can measure vertical beam sizes of
$10-100~\mu$m on a turn-by-turn, bunch-by-bunch basis at $e^\pm$ beam energies
of $\sim2~$GeV. At such beam energies the xBSM images x-rays of
$\epsilon\approx$1-10$~$keV ($\lambda\approx 0.1-1$ nm) that emerge from a
hard-bend magnet through a single- or multiple-slit (coded aperture) optical
element onto an array of 32 InGaAs photodiodes with 50$~\mu$m pitch. Beamlines
and detectors are entirely in-vacuum, enabling single-shot beam size
measurement down to below 0.1$~$mA ($2.5\times10^9$ particles) per bunch and
inter-bunch spacing of as little as 4$~$ns. At $E_{\rm b}=2.1 $GeV, systematic
precision of $\sim 1~\mu$m is achieved for a beam size of $\sim12~\mu$m; this
is expected to scale as $\propto 1/\sigma_{\rm b}$ and $\propto 1/E_{\rm b}$.
Achieving this precision requires comprehensive alignment and calibration of
the detector, optical elements, and x-ray beam. Data from the xBSM have been
used to extract characteristics of beam oscillations on long and short
timescales, and to make detailed studies of low-emittance tuning, intra-beam
scattering, electron cloud effects, and multi-bunch instabilities.


title:
Supergravity Inflation with Broken Shift Symmetry and Large
  Tensor-to-Scalar Ratio

abstract:
  We propose a class of inflation models with potential V(\phi)=\alpha \phi^n
exp(-\beta^m \phi^m). We show that such kind of inflaton potentials can be
realized in supergravity theory with a small shift symmetry breaking term in
the K\"ahler potential. We find that the models with (m=1, n=1), (m=1, n=2),
(m=2, n=1), and (m=2, n=3/2) can easily accommodate the Planck results. In
particular, the tensor-to-scalar ratio is larger than 0.01 in the 1\sigma
region. Thus, these models generate the typical large field inflation, and can
be tested at the future Planck and QUBIC experiments.


title:
Geometrical comparison of two protein structures using Wigner-D
  functions

abstract:
  In this paper, we develop a quantitative comparison method for two arbitrary
protein structures. This method uses a root-mean-square deviation (RMSD)
characterization and employs a series expansion of the protein's shape function
in terms of the Wigner-D functions to define a new criterion, which is called a
"similarity value". We further demonstrate that the expansion coefficients for
the shape function obtained with the help of the Wigner-D functions correspond
to structure factors. Our method addresses the common problem of comparing two
proteins with different numbers of atoms. We illustrate it with a worked
example.


title:
Triangulations of $\Delta_{n-1} \times \Delta_{d-1}$ and Matching
  Ensembles

abstract:
  We suggest an axiom system for a collection of matchings that describes the
triangulation of product of simplices.


title: Estimates on complex eigenvalues for Dirac operators on the half-line

abstract:
  We derive bounds on the location of non-embedded eigenvalues of Dirac
operators on the half-line with non-Hermitian $L^1$-potentials. The results are
sharp in the non-relativistic or weak-coupling limit. In the massless case, the
absence of discrete spectrum is proved under a smallness assumption.


title:
LArSoft: A Software Package for Liquid Argon Time Projection Drift
  Chambers

abstract:
  We describe in these GLA2011 proceedings the software package LArSoft, a
toolkit to perform simulation, analysis and reconstruction with the Liquid
Argon (LAr) Time Projection Chambers (TPCs) within the US program of proposed
detectors. We demonstrate that LArSoft is a fast-maturing, sophisticated
package which has taken on important analyses already, and which stands ready
to be adopted by as many as five Liquid Argon Time Projection Chambers.


title:
Transition from insulating to metallic phase induced by in-plane
  magnetic field in HgTe quantum wells

abstract:
  We report transport measurements in HgTe-based quantum wells with well width
of 8 nm, corresponding to quantum spin Hall state, subject to in-plane magnetic
field. In the absence of the magnetic field the local and nonlocal resistances
behave very similar, which confirms the edge state transport in our system. In
the magnetic field, we observe a monotonic decrease of the resistance with
saturation of local resistance, while nonlocal resistance disappears
completely, independent of the gate voltage. We believe that these evidences of
metallic behavior indicate a transition to a gapless two-dimensional phase,
according to theoretical predictions. The influence of disorder on resistivity
properties of HgTe quantum wells under in-plane magnetic field is discussed.


title: Green's function for longitudinal shear of a periodic laminate

abstract:
  The reasoning is a slight extension of that employed in my article [1] and
its further development [2]. A formal solution to the title problem is
presented for a general periodic laminate and its application for the
construction of "effective constitutive relations" is developed. Its
implementation in detail will be reported separately.


title: Quantum Algorithms for Learning Symmetric Juntas via the Adversary Bound

abstract:
  In this paper, we study the following variant of the junta learning problem.
We are given oracle access to a Boolean function $f$ on $n$ variables that only
depends on $k$ variables, and, when restricted to them, equals some predefined
function $h$. The task is to identify the variables the function depends on.
When $h$ is the XOR or the OR function, this gives a restricted variant of the
Bernstein-Vazirani or the combinatorial group testing problem, respectively.
  We analyse the general case using the adversary bound, and give an
alternative formulation for the quantum query complexity of this problem. We
construct optimal quantum query algorithms for the cases when $h$ is the OR
function (complexity is $\Theta(\sqrt{k})$) or the exact-half function
(complexity is $\Theta(k^{1/4})$). The first algorithm resolves an open problem
from arXiv:1210.1148. For the case when $h$ is the majority function, we prove
an upper bound of $O(k^{1/4})$. All these algorithms can be made exact.
  We obtain a quartic improvement when compared to the randomised complexity
(if $h$ is the exact-half or the majority function), and a quadratic one when
compared to the non-adaptive quantum complexity (for all functions considered
in the paper).


title:
Probing Cosmic-Ray Ion Acceleration with Radio-Submm and Gamma-Ray
  Emission from Interaction-Powered Supernovae

abstract:
  The optical and near-IR emission from some classes of supernovae (SNe),
including Type IIn and possibly some super-luminous SNe, is likely powered by a
collision between the SN ejecta and dense circumstellar material (CSM). We
argue that for a range of CSM masses and their radii, a collisionless shock can
form, allowing for efficient cosmic-ray (CR) acceleration. We show that pp
collisions between these newly accelerated CRs and the CSM leads to not only
gamma rays but also secondary electrons and positrons that radiate synchrotron
photons in the high-frequency radio bands. Our estimates imply that various
facilities including the Jansky Very Large Array (VLA) and the Atacama Large
Millimeter/submillimeter Array (ALMA) may observe such SNe at Gpc distances by
followup observations in months-to-years, although the detectability strongly
depends on the CSM density as well as observed frequency. Detecting this signal
would give us a unique probe of CR acceleration at early times, and even
non-detections can put interesting limits on the possibility of CR ion
acceleration. Following our previous work, we also show that GeV gamma rays can
escape from the system without severe attenuation, encouraging point-source and
stacking analyses with Fermi. We provide recipes for diagnosing
interaction-powered SN scenario with multi-messenger (neutrino and gamma-ray)
observations.


title: Minimal failure probability for ceramic design via shape control

abstract:
  We consider the probability of failure for components made of brittle mate-
rials under one time application of a load as introduced by Weibull and Batdorf
- Crosse and more recently studied by NASA and the STAU cooperation as an
objective functional in shape optimization and prove the existence of optimal
shapes in the class of shapes with a uniform cone property. The corresponding
integrand of the objective functional has convexity properties that allow to
derive lower-semicontinuity according to Fujii (Opt. Th. Appl. 1988). These
properties require less restrictive regularity assumptions for the boundaries
and state functions compared to [arXiv:1210.4954]. Thereby, the weak
formulation of linear elasticity can be kept for the abstract setting for shape
optimization as presented in the book by Haslinger and Maekinen.


title: Titan-Hyperion Resonance and the Tidal Q of Saturn

abstract:
  Lainey et al. (2012), by re-analyzing long-baseline astrometry of Saturn's
moons, have found that the moons' tidal evolution is much faster than
previously thought, implying an order of magnitude stronger tidal dissipation
within Saturn. This result is controversial and implies recent formation of at
least some of the mid-sized icy moons of Saturn. Here we show that this more
intensive tidal dissipation is in full agreement with the evolved state of the
Titan-Hyperion resonance. This resonance was previously thought to be non-tidal
in origin, as the amount of tidal evolution required for its assembly is beyond
what is possible in models that assume that all the major moons are primordial.
We find that the survival of the Titan-Hyperion resonance is in agreement with
a past Titan-Iapetus 5:1 resonance, but not with unbroken tidal evolution of
Rhea from the rings to its current distance.


title: On the Limits of Information Retrieval in Quantum Mechanics

abstract:
  The widely considered assertion is that the unitarity of quantum mechanical
evolution assures the preservation of information. It is even promoted in
popular literature as an established fact. (Susskind, 2008) Yet, a simple chain
of reasoning demonstrates that: 1) almost any evolutionary operator can be well
approximated by a degenerate (finite-rank) operator and 2) one needs an
eternity to retrieve information exactly from a nonstationary quantum state and
to distinguish between arbitrary unitary operator and its finite-dimensional
approximations.


title: Questions and Remarks on Discrete and Dense Subgroups of Diff(I)

abstract:
  We are raising questions on discrete and dense subgroups of Diff(I). Most of
the questions are around the problems discussed in [A1]-[A4].


title:
Local Spectrum of Truncations of Kronecker Products of Haar Distributed
  Unitary Matrices

abstract:
  We address the local spectral behavior of the random matrix $\Pi_1 U^{\otimes
k} \Pi_2 U^{\otimes k *} \Pi_1$, where $U$ is a Haar distributed unitary matrix
of size $n\times n$, the factor $k$ is at most $c_0\log n$ for a small constant
$c_0>0$, and $\Pi_1,\Pi_2$ are arbitrary projections on $\ell_2^{n^k}$ of ranks
proportional to $n^k$. We prove that in this setting the $k$-fold Kronecker
product behaves similarly to the well-studied case when $k=1$.


title: Entanglement-swapping for X-states demands threshold values

abstract:
  The basic entanglement-swapping scheme can be seen as a process which allows
to redistribute the Bell states' properties between different pairs of a four
qubits system. Achieving the task requires performing a von Neumann
measurement, which projects a pair of factorized qubits randomly onto one of
the four Bell states. In this work we propose a similar scheme, by performing
the same Bell-von Neumann measurement over two local qubits, each one initially
being correlated through an X-state with a spatially distant qubit. This
process swaps the X-feature without conditions, whereas the input entanglement
is partially distributed in the four possible outcome states under certain
conditions. Specifically, we obtain two threshold values for the input
entanglement in order for the outcome states to be nonseparable. Besides, we
find that there are two possible amounts of outcome entanglement, one is
greater and the other less than the input entanglement; the probability of
obtaining the greatest outcome entanglement is smaller than the probability of
achieving the least one. In addition, we illustrate the distribution of the
entanglement for some particular and interesting initial X-states.


title:
Interest communities and flow roles in directed networks: the Twitter
  network of the UK riots

abstract:
  Directionality is a crucial ingredient in many complex networks in which
information, energy or influence are transmitted. In such directed networks,
analysing flows (and not only the strength of connections) is crucial to reveal
important features of the network that might go undetected if the orientation
of connections is ignored. We showcase here a flow-based approach for community
detection in networks through the study of the network of the most influential
Twitter users during the 2011 riots in England. Firstly, we use directed Markov
Stability to extract descriptions of the network at different levels of
coarseness in terms of interest communities, i.e., groups of nodes within which
flows of information are contained and reinforced. Such interest communities
reveal user groupings according to location, profession, employer, and topic.
The study of flows also allows us to generate an interest distance, which
affords a personalised view of the attention in the network as viewed from the
vantage point of any given user. Secondly, we analyse the profiles of incoming
and outgoing long-range flows with a combined approach of role-based similarity
and the novel relaxed minimum spanning tree algorithm to reveal that the users
in the network can be classified into five roles. These flow roles go beyond
the standard leader/follower dichotomy and differ from classifications based on
regular/structural equivalence. We then show that the interest communities fall
into distinct informational organigrams characterised by a different mix of
user roles reflecting the quality of dialogue within them. Our generic
framework can be used to provide insight into how flows are generated,
distributed, preserved and consumed in directed networks.


title:
Fully pseudospectral solution of the conformally invariant wave equation
  near the cylinder at spacelike infinity

abstract:
  We study the scalar, conformally invariant wave equation on a
four-dimensional Minkowski background in spherical symmetry, using a fully
pseudospectral numerical scheme. Thereby, our main interest is in a suitable
treatment of spatial infinity, which is represented as a cylinder. We consider
both Cauchy problems, where we evolve data from a Cauchy surface to future null
infinity, as well as characteristic initial value problems with data at past
null infinity, and demonstrate that highly accurate numerical solutions can be
obtained for a small number of grid points.


title: Constructing Pauli pulse schemes for decoupling and quantum simulation

abstract:
  Dynamical decoupling is a powerful technique to suppress errors in quantum
systems originating from environmental couplings or from unwanted
inter-particle interactions. However, it can also be used to selectively
decouple specific couplings in a quantum system. We present a simple and
easy-to-use general method to construct such selective decoupling schemes on
qubit and qudit networks by means of (generalized) Pauli operations. As these
constructed schemes can suppress Hamiltonian interactions on general qudit
networks selectively, they are well suited for purposes of approximate quantum
simulation. Some examples are presented, demonstrating the use of our method
and the resulting decoupling schemes.


title: Twisted Analytic Torsion and Adiabatic Limits

abstract:
  We study an analogue of the analytic torsion for elliptic complexes that are
graded by $\mathbb{Z}_2$, orignally constructed by Mathai and Wu. Motivated by
topological T-duality, Bouwknegt an Mathai study the complex of forms on an
odd-dimensional manifold equipped with with the twisted differential $d_H =
d+H$, where $H$ is a closed odd-dimensional form. We show that the Ray-Singer
metric on this twisted determinant is equal to the untwisted Ray-Singer metric
when the determinant lines are identified using a canonical isomorphism. We
also study another analytical invariant of the twisted differential, the
derived Euler characteristic $\chi'(d_H)$, as defined by Bismut and Zhang.


title: On ground model definability

abstract:
  Laver, and Woodin independently, showed that models of ${\rm ZFC}$ are
uniformly definable in their set-forcing extensions, using a ground model
parameter. We investigate ground model definability for models of fragments of
${\rm ZFC}$, particularly of ${\rm ZF}+{\rm DC}_\delta$ and of ${\rm ZFC}^-$,
and we obtain both positive and negative results. Generalizing the results of
Laver and Woodin, we show that models of ${\rm ZF}+{\rm DC}_\delta$ are
uniformly definable in their set-forcing extensions by posets admitting a gap
at $\delta$, using a ground model parameter. In particular, this means that
models of ${\rm ZF}+{\rm DC}_\delta$ are uniformly definable in their forcing
extensions by posets of size less than $\delta$. We also show that it is
consistent for ground model definability to fail for models of ${\rm ZFC}^-$ of
the form $H_{\kappa^+}$. Using forcing, we produce a ${\rm ZFC}$ universe in
which there is a cardinal $\kappa>\!>\omega$ such that $H_{\kappa^+}$ is not
definable in its Cohen forcing extension. As a corollary, we show that there is
always a countable transitive model of ${\rm ZFC}^-$ violating ground model
definability. These results turn out to have a bearing on ground model
definability for models of ${\rm ZFC}$. It follows from our proof methods that
the hereditary size of the parameter that Woodin used to define a ${\rm ZFC}$
model in its set-forcing extension is best possible.


title: William Sadler Franks and the Brockhurst Observatory

abstract:
  William Sadler Franks (1851-1935) was astronomer-in-charge at F.J. Hanbury's
private observatory at Brockhurst, near East Grinstead, Sussex, from 1909 until
his death in 1935. This paper reviews the observational projects Franks
undertook at Brockhurst, including his work on double stars, red stars, diffuse
nebulae and dark nebulae, as well as his involvement with the commissioning of
a 24-inch reflector built by Thomas William Bush (1839-1928).


title: Pseudo-effective and nef cones on spherical varieties

abstract:
  We show that nef cycle classes on smooth complete spherical varieties are
effective, and the products of nef cycle classes are also nef. Let X be a
smooth projective spherical variety such that its effective cycle classes of
codimension k are nef, where 1<= k <= dim(X)-1. We study the properties of X.
And we show that if X is a toric variety, then X is isomorphic to the product
of some projective spaces; if X is toroidal, then X is isomorphic to a rational
homogeneous space; if X is horospherical, dim(X)>= 3 and k=2, then effective
divisors on X are nef; if X is horospherical and effective divisors on X are
nef, then there is a morphism from X to a rational homogeneous space such that
each fiber is isomorphic to the product of some horospherical varieties of
Picard number one.


title:
Analysis of some basic approaches to finite strain elasto-plasticity in
  view of reference change

abstract:
  There is a large variety of concepts used to generalize the classical
Prandtl-Reuss relations of infinitesimal elasto-plasticity to finite strains.
In this work, some basic approaches are compared in a qualitative way with
respect to a certain invariance property. These basic approaches include the
additive hypoelasto-plasticity with corotational stress rates, additive
plasticity in the logarithmic strain space, and multiplicative
hyperelasto-plasticity.
  The notion of weak invariance is introduced in this study. Roughly speaking,
a material model is weakly invariant under a certain transformation of the
local reference configuration if this reference change can be neutralized by a
suitable transformation of initial conditions, leaving the remaining
constitutive relations intact. We analyse the basic models in order to find out
if they are weakly invariant under arbitrary volume-preserving transformations
of the reference configuration.
  It is shown that the weak invariance property corresponds to a generalized
symmetry which provides insights into underlying constitutive assumptions. This
property can be used for a systematic study of different frameworks of finite
strain elasto-plasticity. In particular, it can be used as a classification
criterion.


title: Resonant averaging for small solutions of stochastic NLS equations

abstract:
  We consider the free linear Schr\"odinger equation on a torus $\mathbb T^d$,
perturbed by a hamiltonian nonlinearity, driven by a random force and damped by
a linear damping: $$ u_t -i\Delta u +i\nu \rho |u|^{2q_*}u = - \nu f(-\Delta) u
+ \sqrt\nu\,\frac{d}{d t}\sum_{k\in \mathbb Z^d} b_l\beta^k(t)e^{ik\cdot x} \ .
$$ Here $u=u(t,x),\ x\in\mathbb T^d$, $0<\nu\ll 1$, $q_*\in\mathbb N$, $f$ is a
positive continuous function, $\rho$ is a positive parameter and $\beta^k(t)$
are standard independent complex Wiener processes. We are interested in
limiting, as $\nu\to0$, behaviour of distributions of solutions for this
equation and of its stationary measure. Writing the equation in the slow time
$\tau=\nu t$, we prove that the limiting behaviour of the both is described by
the effective equation $$ u_\tau+ f(-\Delta) u = -iF(u)+\frac{d}{d\tau}\sum
b_k\beta^k(\tau)e^{ik\cdot x} \, $$ where the nonlinearity $F(u)$ is made out
of the resonant terms of the monomial $ |u|^{2q_*}u$. We explain the relevance
of this result for the problem of weak turbulence


title:
Derivation of the Kolmogorov-Zakharov equation from the
  resonant-averaged stochastic NLS equation

abstract:
  We suggest a new derivation of a kinetic equation of Kolmogorov-Zakharov (KZ)
type for the spectrum of the weakly nonlinear Schr\"odinger equation with
stochastic forcing. The kynetic equation is obtained as a result of a double
limiting procedure. Firstly, we consider the equation on a finite box with
periodic boundary conditions and send the size of the nonlinearity and of the
forcing to zero, while the time is correspondingly rescaled; then, the size of
the box is sent to infinity (with a suitable rescaling of the solution). We
report here the results of the first limiting procedure, analyzed with full
rigour in arXiv:1311.6793, and show how the second limit leads to a kinetic
equation for the spectrum, if some further hypotheses (commonly employed in the
weak turbulence theory) are accepted. Finally we show how to derive from these
equations the KZ spectra.


title: Regularity of the $p$-Poisson equation in the plane

abstract:
  We study the regularity of the $p$-Poisson equation
  $$
  \Delta_p u = h, \quad h\in L^q
  $$ in the plane. In the case $p>2$ and $2<q<\infty$ we obtain the sharp
H\"older exponent for the gradient. In the other cases we come arbitrarily
close to the sharp exponent.


title:
Sufficient bound on the mode mismatch of single photons for scalability
  of the boson sampling computer

abstract:
  The boson sampler proposed by Aaronson and Arkhipov is a non-universal
quantum computer, which can serve as evidence against the extended
Church-Turing thesis. It samples the probability distribution at the output of
linear unitary optical network, with indistinguishable single photons at the
input. Four experimental groups have already tested their small-scale
prototypes with up to four photons. The boson sampler with few dozens of single
photons is believed to be hard to simulate on a classical computer. For
scalability of a realistic boson sampler with current technology it is
necessary to know the effect of the photon mode mismatch on its operation. Here
a nondeterministic model of the boson sampler is analyzed, which employs
partially indistinguishable single photons emitted by identical sources. A
sufficient condition on the average mutual fidelity $ \langle
\mathcal{F}\rangle$ of the single photons is found, which guarantees that the
realistic boson sampler outperforms the classical computer. Moreover, the boson
sampler computer with partially indistinguishable single photons is scalable
while being beyond the power of classical computers when the single photon mode
mismatch $1-\langle \mathcal{F}\rangle$ scales as $ \mathcal{O}(N^{-3/2})$ with
the total number of photons $N$.


title:
Electrical tuning and switching of an optical frequency comb generated
  in aluminum nitride microring resonators

abstract:
  Aluminum nitride has been shown to possess both strong Kerr nonlinearity and
electro-optic Pockels effect. By combining these two effects, here we
demonstrate on-chip reversible on/off switching of the optical frequency comb
generated by an aluminum nitride microring resonator. We optimize the design of
gating electrodes and the underneath resonator structure to effectively apply
electric field without increasing the optical loss. The switching of the comb
is monitored by measuring one of the frequency comb peaks while varying the
electric field. The controlled comb electro-optic response is investigated for
direct comparison with the transient thermal effect.


title: New exact cosmologies on the brane

abstract:
  We develop a method for constructing exact cosmological solutions in brane
world cosmology. New classes of cosmological solutions on Randall-Sandrum brane
are obtained. The superpotential and Hubble parameter are represented in
quadratures. These solutions have inflationary phases under general assumptions
and also describe an exit from the inflationary phase without a fine tuning of
the parameters. Another class solutions can describe the current phase of
accelerated expansion with or without possible exit from it.


title: Wavelet and Fast Fourier Transform based analysis of Solar Image

abstract:
  Both of Wavelet and Fast Fourier Transform are strong signal processing tools
in the field of Data Analysis. In this paper fast fourier transform (FFT) and
Wavelet Transform are employed to observe some important features of Solar
image (December, 2004). We have tried to find out the periodicity and coherence
of different sections of the solar image. We plotted the distribution of energy
in solar surface by analyzing the solar image with scalograms and
3D-coefficient plots.


title: Energy-energy correlations in N=4 SYM

abstract:
  We present a new approach to computing energy-energy correlations in gauge
theories that exploits their relation to correlation functions and bypasses the
use of scattering amplitudes. We illustrate its power by calculating
energy-energy correlations in the maximally supersymmetric Yang-Mills theory
(N=4 SYM) in the next-to-leading order approximation.


title:
Surface plasmon assisted electron pair formation in strong
  electromagnetic field

abstract:
  The basis of low-temperature superconductivity has been set to be the pair
formation of electrons, due to their effective attraction. The appearance of an
effective attraction potential has also been predicted for electron-electron
scattering in the presence of a strong, inhomogeneous radiation field. In the
present work the strong electromagnetic fields were created by femtosecond
Ti:Sa lasers, used to excite surface plasmons in gold films at room
temperature, in the Kretschmann geometry. Experimental investigations were
carried out using a surface plasmon near-field scanning tunneling microscope,
by measuring its response to the excitation at hot spots on the gold surface.
Furthermore, the spectra of photoelectrons, liberated by multi-plasmon
absorption, have also been measured by a time-of-flight spectrometer. In both
cases new type of anomalies in the electon signal have been measured in the
same intensity range, whose existence may be qualitatively understood, by using
the intensity-dependent expression for the effective electon-electron
scattering potential, derived earlier in a different context.


title:
Recommending with an Agenda: Active Learning of Private Attributes using
  Matrix Factorization

abstract:
  Recommender systems leverage user demographic information, such as age,
gender, etc., to personalize recommendations and better place their targeted
ads. Oftentimes, users do not volunteer this information due to privacy
concerns, or due to a lack of initiative in filling out their online profiles.
We illustrate a new threat in which a recommender learns private attributes of
users who do not voluntarily disclose them. We design both passive and active
attacks that solicit ratings for strategically selected items, and could thus
be used by a recommender system to pursue this hidden agenda. Our methods are
based on a novel usage of Bayesian matrix factorization in an active learning
setting. Evaluations on multiple datasets illustrate that such attacks are
indeed feasible and use significantly fewer rated items than static inference
methods. Importantly, they succeed without sacrificing the quality of
recommendations to users.


title:
A Sufficient Condition for Disproving Descartes's Conjecture on Odd
  Perfect Numbers

abstract:
  Let $\sigma(x)$ be the sum of the divisors of $x$. If $N$ is odd and
$\sigma(N) = 2N$, then the odd perfect number $N$ is said to be given in
Eulerian form if $N = {q^k}{n^2}$ where $q$ is prime with $q \equiv k \equiv 1
\pmod 4$ and $\gcd(q,n) = 1$. In this note, we show that $q < n$ implies that
Descartes's conjecture (previously Sorli's conjecture), $k = \nu_{q}(N) = 1$,
is not true. This then implies an unconditional proof for the biconditional $$k
= \nu_{q}(N) = 1 \Longleftrightarrow n < q.$$ Lastly, following a recent result
of Cohen and Sorli, we show that if $q < n$, then either $q > 5$ or $k > 5$ is
true.
  (Note: This is withdrawn for now because this paper is currently a work in
progress.)


title:
Categorical Cell Decomposition of Quantized Symplectic Algebraic
  Varieties

abstract:
  We prove a new symplectic analogue of Kashiwara's Equivalence from D-module
theory. As a consequence, we establish a structure theory for module categories
over deformation quantizations that mirrors, at a higher categorical level, the
Bialynicki-Birula stratification of a variety with an action of the
multiplicative group. The resulting categorical cell decomposition provides an
algebro-geometric parallel to the structure of Fukaya categories of Weinstein
manifolds. From it, we derive concrete consequences for invariants such as
K-theory and Hochschild homology of module categories of interest in geometric
representation theory.


title:
First Principles explanation of the positive Seebeck coefficient of
  lithium

abstract:
  Lithium is one of the simplest metals, with negative charge carriers and a
close reproduction of free electron dispersion. Experimentally, however, Li is
one of a handful of elemental solids (along with Cu, Ag, Au etc.) where the
sign of the Seebeck coefficient (S) is opposite to that of the carrier. This
counterintuitive behavior still lacks a satisfactory interpretation. We
calculate S fully from first-principles, within the framework of P.B. Allen's
formulation of Boltzmann transport theory. Here it is crucial to avoid the
constant relaxation time approximation, which gives a sign for S which is
necessarily that of the carriers. Our calculated S are in excellent agreement
with experimental data, up to the melting point. In comparison with another
alkali metal Na, we demonstrate that within the simplest non-trivial model for
the energy dependency of the electron lifetimes, the rapidly increasing density
of states (DOS) across the Fermi energy is related to the sign of S in Li. The
exceptional energy dependence of the DOS is beyond the free-electron model, as
the dispersion is distorted by the Brillouin Zone edge, a stronger effect in Li
than other Aliki metals. The electron lifetime dependency on energy is central,
but the details of the electron-phonon interaction are found to be less
important, contrary to what has been believed for several decades. Band
engineering combined with the mechanism exposed here may open the door to new
"ambipolar" thermoelectric materials, with a tunable sign for the thermopower
even if either n- or p-type doping is impossible.


title: Prevalence of Earth-size planets orbiting Sun-like stars

abstract:
  Determining whether Earth-like planets are common or rare looms as a
touchstone in the question of life in the universe. We searched for Earth-size
planets that cross in front of their host stars by examining the brightness
measurements of 42,000 stars from National Aeronautics and Space
Administration's Kepler mission. We found 603 planets, including 10 that are
Earth size (1-2 Earth-radii) and receive comparable levels of stellar energy to
that of Earth (within a factor of four). We account for Kepler's imperfect
detectability of such planets by injecting synthetic planet-caused dimmings
into the Kepler brightness measurements and recording the fraction detected. We
find that $11\pm4%$ of Sun-like stars harbor an Earth-size planet receiving
between one and four times the stellar intensity as Earth. We also find that
the occurrence of Earth-size planets is constant with increasing orbital period
(P), within equal intervals of logP up to $\sim200$ d. Extrapolating, one finds
$5.7^{+1.7}_{-2.2}%$ of Sun-like stars harbor an Earth-size planet with orbital
periods of 200-400 d.


title:
Multi-scale comparative spectral analysis of satellite total solar
  irradiance measurements from 2003 to 2013 reveals a planetary modulation of
  solar activity and its non-linear dependence on the 11-year solar cycle

abstract:
  Herein we adopt a multi-scale dynamical spectral analysis technique to
compare and study the dynamical evolution of the harmonic components of the
overlapping ACRIMSAT/ACRIM3, SOHO/VIRGO and SORCE/TIM total solar irradiance
(TSI) records during 2003.15 to 2013.16 in solar cycles 23 and 24. The three
TSI time series present highly correlated patterns. Significant power spectral
peaks are common to these records and are observed at the following periods:
0.070 year, 0.097 year, 0.20 year, 0.25 year, 0.30-0.34 year, 0.39 year. Less
certain spectral peaks occur at about 0.55 year, 0.60-0.65 year and 0.7-0.9
year. Four main frequency periods at 24.8 days (0.068 year), 27.3 days (0.075
year), at 34-35 days (0.093-0.096 year) and 36-38 days (0.099-0.104 year)
characterize the solar rotation cycle. The amplitude of these oscillations, in
particular of those with periods larger than 0.5 year, appears to be modulated
by the 11-year solar cycle. Similar harmonics have been found in other solar
indices. The observed periodicities are found highly coherent with the spring,
orbital and synodic periods of Mercury, Venus, Earth and Jupiter. We conclude
that solar activity is likely modulated by planetary gravitational and
electromagnetic forces acting on the sun. The strength of the sun's response to
planetary forcing depends non-linearly on the state of internal solar dynamics:
planetary-sun coupling effects are enhanced during solar activity maxima and
attenuated during minima.


title:
Coherent cooling of atoms in a frequency-modulated standing laser wave:
  wave function and stochastic trajectory approaches

abstract:
  The wave function of a moderately cold atom in a stationary near-resonant
standing light wave delocalizes very fast due to wave packet splitting.
However, we show that frequency modulation of the field may suppress packet
splitting for some atoms having specific velocities in a narrow range. These
atoms remain localized in a small space for a long time. We demonstrate and
explain this effect numerically and analytically. Also we demonstrate that
modulated field can not only trap, but also cool the atoms. We perform a
numerical experiment with a large atomic ensebmble having wide initial velocity
and energy distribution. During the experiment, most of atoms leave the wave
while trapped atoms have narrow energy distribution


title:
A Novel Family of Adaptive Filtering Algorithms Based on The Logarithmic
  Cost

abstract:
  We introduce a novel family of adaptive filtering algorithms based on a
relative logarithmic cost. The new family intrinsically combines the higher and
lower order measures of the error into a single continuous update based on the
error amount. We introduce important members of this family of algorithms such
as the least mean logarithmic square (LMLS) and least logarithmic absolute
difference (LLAD) algorithms that improve the convergence performance of the
conventional algorithms. However, our approach and analysis are generic such
that they cover other well-known cost functions as described in the paper. The
LMLS algorithm achieves comparable convergence performance with the least mean
fourth (LMF) algorithm and extends the stability bound on the step size. The
LLAD and least mean square (LMS) algorithms demonstrate similar convergence
performance in impulse-free noise environments while the LLAD algorithm is
robust against impulsive interferences and outperforms the sign algorithm (SA).
We analyze the transient, steady state and tracking performance of the
introduced algorithms and demonstrate the match of the theoretical analyzes and
simulation results. We show the extended stability bound of the LMLS algorithm
and analyze the robustness of the LLAD algorithm against impulsive
interferences. Finally, we demonstrate the performance of our algorithms in
different scenarios through numerical examples.


title:
Identification of geometrical and elastostatic parameters of heavy
  industrial robots

abstract:
  The paper focuses on the stiffness modeling of heavy industrial robots with
gravity compensators. The main attention is paid to the identification of
geometrical and elastostatic parameters and calibration accuracy. To reduce
impact of the measurement errors, the set of manipulator configurations for
calibration experiments is optimized with respect to the proposed performance
measure related to the end-effector position accuracy. Experimental results are
presented that illustrate the advantages of the developed technique.


title:
Digitize Your Body and Action in 3-D at Over 10 FPS: Real Time Dense
  Voxel Reconstruction and Marker-less Motion Tracking via GPU Acceleration

abstract:
  In this paper, we present an approach to reconstruct 3-D human motion from
multi-cameras and track human skeleton using the reconstructed human 3-D point
(voxel) cloud. We use an improved and more robust algorithm, probabilistic
shape from silhouette to reconstruct human voxel. In addition, the annealed
particle filter is applied for tracking, where the measurement is computed
using the reprojection of reconstructed voxel. We use two different ways to
accelerate the approach. For the CPU only acceleration, we leverage Intel TBB
to speed up the hot spot of the computational overhead and reached an
accelerating ratio of 3.5 on a 4-core CPU. Moreover, we implement an
intensively paralleled version via GPU acceleration without TBB. Taking account
all data transfer and computing time, the GPU version is about 400 times faster
than the original CPU implementation, leading the approach to run at a
real-time speed.


title:
The role of cluster mergers and travelling shocks in shaping the
  H$\alpha$ luminosity function at $\bf z\sim0.2$: `sausage' and `toothbrush'
  clusters

abstract:
  The most extreme cluster mergers can lead to massive cluster-wide travelling
shock waves. The CIZA J2242.8+5301 ('sausage') and 1RXS J0603.3+4213
(`toothbrush') clusters ($z\sim0.2$) host enormous radio-emitting shocks with
simple geometry. We investigate the role of mergers and shocks in shaping the
H$\alpha$ luminosity function, using custom-made narrow-band filters matching
the cluster redshifts mounted on the INT. We surveyed $\sim0.28$ deg$^2$ for
each cluster and found $181$ line emitters in the `sausage' (volume of
$3.371\times10^3$ Mpc$^3$ for H$\alpha$ at $z=0.1945$) and $141$ in the
`toothbrush' ($4.546\times10^3$ Mpc$^3$ for H$\alpha$ at $z=0.225$), out of
which $49$ (`sausage') and $30$ (`toothbrush') are expected to be H$\alpha$. We
build luminosity functions for the field-of-view down to an average limiting
star formation rate of $0.14$ M$_{\odot}$ yr$^{-1}$, find good agreement with
field luminosity functions at $z=0.2$, but significant differences between the
shapes of the luminosity functions for the two clusters. We discover extended,
tens-of-kpc-wide H$\alpha$ haloes in galaxies neighbouring relics, which were
possibly disrupted by the passage of the shock wave. By comparing the `sausage'
cluster with blank fields and other clusters, we also uncover an order of
magnitude boost (at $9\sigma$ level) in the normalisation $\phi^*$ of the
luminosity function in the relic areas. Our results suggest that cluster
mergers may play an important role in the evolution of cluster galaxies through
shock-induced star formation.


title: Lensing and time-delay contributions to galaxy correlations

abstract:
  Galaxy clustering on very large scales can be probed via the 2-point
correlation function in the general case of wide and deep separations,
including all the lightcone and relativistic effects. Using our recently
developed formalism, we analyze the behavior of the local and integrated
contributions and how these depend on redshift range, linear and angular
separations and luminosity function. Relativistic corrections to the local part
of the correlation can be non-negligible but they remain generally
sub-dominant. On the other hand, the additional correlations arising from
lensing convergence and time-delay effects can become very important and even
dominate the observed total correlation function. We investigate different
configurations formed by the observer and the pair of galaxies, and we find
that the case of near-radial large-scale separations is where these effects
will be the most important.


title: A physical model for the flickering variability in cataclysmic variables

abstract:
  Aperiodic broad-band variability (also known as flickering) is observed
throughout all types of accreting compact objects. Many statistical properties
of this variability can be naturally explained with the fluctuating accretion
disk model, where variations in the mass-transfer rate through the disk are
modulated on the local viscous timescale and propagate towards the central
compact object. Here, a recently developed implementation of the model is
applied for the first time to the time-averaged, high-frequency variability of
a cataclysmic variable star (MV Lyrae) observed with the Kepler satellite. A
qualitatively good fit to the data is achieved, suggesting the presence of
geometrically thick inner flow with large viscosity parameter, extending from
$\sim0.12R_{\odot}$ all the way to the white dwarf surface. A simple spectral
model of the system suggests that the geometrically thick component would not
contribute much to the observed optical flux originating from the geometrically
thin outer disk. Instead, X-ray reprocessing from the geometrically thick disk
onto the thin disk is proposed as a mechanism to explain the observed
variability. Similar flows are also deduced in accreting neutron stars/black
holes (X-ray binaries) and Active Galactic Nuclei. Additionally, eclipse
mapping studies of cataclysmic variables also seem to suggest the presence of a
geometrically extended flow towards the inner-edges of the accretion disk. The
fluctuating accretion disk model applied here is encouraging in understanding
the origin of flickering in cataclysmic variables, as well as in X-ray binaries
and Active Galactic Nuclei, by providing a unifying scheme by which to explain
the observed broad-band variability features observed throughout all compact
accreting systems.


title:
Anomalous gauge couplings from composite Higgs and warped extra
  dimensions

abstract:
  We examine trilinear and quartic anomalous gauge couplings (AGCs) generated
in composite Higgs models and models with warped extra dimensions. We first
revisit the SU(2)_L x U(1)_Y effective Lagrangian and derive the charged and
two-photon neutral AGCs. We derive the general perturbative contributions to
the pure field-strength operators from spin 0, 1/2, 1 resonances by means of
the heat kernel method. In the composite Higgs framework, we derive the pattern
of expected deviations from typical SO(N) embeddings of the light composite top
partner. We then study a generic warped extra dimension framework with AdS_5
background, recasting in few parameters the features of models relevant for
AGCs. We also present a detailed study of the latest bounds from electroweak
and Higgs precision observables, with and without brane kinetic terms. For
vanishing brane kinetic terms, we find that the S and T parameters exclude KK
gauge modes of the RS custodial [non-custodial] scenario below 7.7 [14.7] TeV,
for a brane Higgs and below 6.6 [8.1] TeV for a Pseudo Nambu-Goldstone Higgs,
at 95% CL. These constraints can be relaxed in presence of brane kinetic terms.
The leading AGCs are probing the KK gravitons and the KK modes of bulk gauge
fields in parts of the parameter space. In these scenarios, the future CMS and
ATLAS forward proton detectors could be sensitive to the effect of KK gravitons
in the multi-TeV mass range.


title: The Long-Term Dynamical Evolution of Planetary Systems

abstract:
  This chapter concerns the long-term dynamical evolution of planetary systems
from both theoretical and observational perspectives. We begin by discussing
the planet-planet interactions that take place within our own Solar System. We
then describe such interactions in more tightly-packed planetary systems. As
planet-planet interactions build up, some systems become dynamically unstable,
leading to strong encounters and ultimately either ejections or collisions of
planets. After discussing the basic physical processes involved, we consider
how these interactions apply to extrasolar planetary systems and explore the
constraints provided by observed systems. The presence of a residual
planetesimal disc can lead to planetary migration and hence cause instabilities
induced by resonance crossing; however, such discs can also stabilise planetary
systems. The crowded birth environment of a planetary system can have a
significant impact: close encounters and binary companions can act to
destabilise systems, or sculpt their properties. In the case of binaries, the
Kozai mechanism can place planets on extremely eccentric orbits which may later
circularise to produce hot Jupiters.


title: BAO cosmography

abstract:
  Cosmography provides a model-independent way to map the expansion history of
the Universe. In this paper we simulate a Euclid-like survey and explore
cosmographic constraints from future Baryonic Acoustic Oscillations (BAO)
observations. We derive general expressions for the BAO transverse and radial
modes and discuss the optimal order of the cosmographic expansion that provide
reliable cosmological constraints. Through constraints on the deceleration and
jerk parameters, we show that future BAO data have the potential to provide a
model-independent check of the cosmic acceleration as well as a discrimination
between the standard $\Lambda$CDM model and alternative mechanisms of cosmic
acceleration.


title:
The 3 Ms Chandra Campaign on Sgr A*: A Census of X-ray Flaring Activity
  from the Galactic Center

abstract:
  Over the last decade, X-ray observations of Sgr A* have revealed a black hole
in a deep sleep, punctuated roughly once per day by brief flares. The extreme
X-ray faintness of this supermassive black hole has been a long-standing puzzle
in black hole accretion. To study the accretion processes in the Galactic
Center, Chandra (in concert with numerous ground- and space-based
observatories) undertook a 3 Ms campaign on Sgr A* in 2012. With its excellent
observing cadence, sensitivity, and spectral resolution, this Chandra X-ray
Visionary Project (XVP) provides an unprecedented opportunity to study the
behavior of the closest supermassive black hole. We present a progress report
from our ongoing study of X-ray flares, including the brightest flare ever seen
from Sgr A*. Focusing on the statistics of the flares and the quiescent
emission, we discuss the physical implications of X-ray variability in the
Galactic Center.


title:
Spatial Correlations and the Insulating Phase of the High-$T_c$
  Cuprates: Insights from a Configuration-Interaction-Based Solver for
  Dynamical Mean Field Theory

abstract:
  A recently proposed configuration-interaction based impurity solver is used
in combination with the single-site and four-site cluster dynamical mean field
approximations to investigate the three-band copper oxide model believed to
describe the electronic structure of high transition temperature copper-oxide
superconductors. Use of the configuration interaction solver enables
verification of the convergence of results with respect to the number of bath
orbitals. The spatial correlations included in the cluster approximation
substantially shift the metal-insulator phase boundary relative to the
prediction of the single-site approximation and increase the predicted energy
gap of the insulating phase by about 1 eV above the single-site result. Vertex
corrections occurring in the four-site approximation act to dramatically
increase the value of the optical conductivity near the gap edge, resulting in
a better agreement with the data. The calculations reveal two distinct
correlated insulating states: the `magnetically correlated insulator', in which
nontrivial intersite correlations play an essential role in stabilizing the
insulating state, and the strongly correlated insulator, in which local physics
suffices. Comparison of the calculations to the data place the cuprates in the
magnetically correlated Mott insulator regime.


title: Matrix Elements for $D$- and $B$-Mixing from 2+1 Flavor Lattice QCD

abstract:
  We present the status of our calculation of hadronic matrix elements for $D$-
and $B$-meson mixing. We use a large set of the MILC collaboration's $N_f=2+1$
asqtad ensembles, which includes lattice spacings in the range
$a\approx0.12$-0.045 fm, and up/down to strange quark mass ratios as low as
0.05. The asqtad action is also employed for the light valence quarks. For the
heavy quarks we use the Sheikholeslami-Wohlert action with the Fermilab
interpretation. Our calculation covers the complete set of five local operators
needed to describe $B$-meson mixing in the Standard Model and Beyond. In the
charm sector, our calculation of local mixing matrix elements may be used to
constrain new physics models. We present final correlator fit results on the
full data set for the $B$-meson mixing project and preliminary fit results for
the $D$-meson mixing project.


title: A Class of Orthogonal Sequences

abstract:
  This paper presents a class of random orthogonal sequences associated with
the number theoretic Hilbert transform. We present a constructive procedure for
finding the random sequences for different modulus values. These random
sequences have autocorrelation function that is zero everywhere excepting at
the origin. These sequences may be used as keys and in other cryptography
applications.


title:
Marrying {\it ab initio} calculations and Halo-EFT: the case of
  ${}^7{\rm Li} + n \rightarrow {}^8{\rm Li} + \gamma$

abstract:
  We report a leading-order calculation of radiative ${}^{7}\mathrm{Li}$
neutron captures to both the ground and first excited state of
${}^{8}\mathrm{Li}$ in the framework of a low-energy effective field theory
(Halo-EFT). Each of the possible final states is treated as a shallow bound
state composed of both $n+{}^{7}\mathrm{Li}$ and $n+{}^{7}\mathrm{Li}^{*}$
(core excitation) configurations. The {\it ab initio} variational Monte Carlo
method is used to compute the asymptotic normalization coefficients of these
bound states, which are then used to fix couplings in our EFT. We calculate the
total and partial cross sections in the radiative capture process using this
calibrated EFT. Fair agreement with measured total cross sections is achieved
and excellent agreement with the measured branching ratio between the two final
states is found. In contrast,a previous Halo-EFT calculation [G. Rupak and R.
Higa, Phys. Rev. Lett {\bf 106}, 222501 (2011)] assumes that the
$n$-${}^{7}\mathrm{Li}$ couplings in different spin channels are equal, fits
the $P$-wave "effective-range" parameter to the threshold cross section for
${}^7{\rm Li} + n \rightarrow {}^8{\rm Li} + \gamma$, and assumes the core
excitation is at high enough energy scale that it can be integrated out.


title: Composite Higgsino

abstract:
  Several supersymmetric models in which there is a (partially) composite Higgs
boson arising from (coupled to) a strong sector have been proposed. Such strong
dynamics would help to cause the electroweak symmetry breaking naturally. In
this paper, we focus on the compositeness of the Higgsinos in such models. We
show that such a Higgsino compositeness can induce the characteristic decay
branching fraction of the neutralinos. In such scenarios, the decay branching
fraction of the second lightest neutral Higgsino into the lightest neutral
Higgsino with photon can be large due to a dipole interaction. We also discuss
the Higgsino dark matter feature. The annihilation cross section into gamma Z
can be large.


title: Plasmon-supported emission of entangled photons and zero-point energy

abstract:
  Emission of pairs of photons in the interface metal-dielectric under the
laser excitation arising due to the time-dependent perturbation of the
zero-point fluctuations of the electromagnetic field by photons of the laser is
considered. The enhancement of this emission by surface plasmons may be used
for getting polarization-entangled photons. A possibility to compensate the
energy of the zero-point fluctuations of bosons by other fluctuations with
negative energy is discussed.


title: Dynamics of the chiral phase transition

abstract:
  The intention of this study is the search for signatures of the chiral phase
transition in heavy-ion collisions. To investigate the impact of fluctuations,
e.g., of the baryon number, at the transition or at a critical point, the
linear sigma model is treated in a dynamical (3+1)-dimensional numerical
simulation. Chiral fields are approximated as classical mean fields, and quarks
are described as quasi particles in a Vlasov equation. Additional dynamics is
implemented by quark-quark and quark-sigma-field interactions. For a consistent
description of field-particle interactions, a new Monte-Carlo-Langevin-like
formalism has been developed and is discussed.


title:
EPECUR setup for the search of narrow baryon resonances in the
  pion-proton scattering

abstract:
  EPECUR experimental setup is aimed at the search of narrow resonant states by
precision measurement of differential and total reaction cross sections of
pion-nucleon interaction with 1 MeV pion energy steps. In five years passed
from the idea of the experiment till the start of the data taking in April of
2009, a new apparatus was build from scratch at the universal beam line 322 of
ITEP proton synchrotron U-10. The setup is essentially a non-magnetic
spectrometer with a liquid hydrogen target based on the large aperture drift
chambers with hexagonal structure. The unique properties of the beam line allow
individual pion momentum measurement with the accuracy better than 0.1%. The
momentum tagging is done with 1 mm pitch proportional chambers located in the
first focus of the beam line. The design of numerous subsystems of the setup is
based on modern electronic components including microprocessors and FPGA. All
the subsystems are tuned and tested both individually and as parts of the whole
working setup. The distributed data acquisition system uses widely spread USB
and Ethernet protocols, which allows to achieve high performance and take full
advantage of the industrial solutions.


title: Electronic and plasmonic phenomena at graphene grain boundaries

abstract:
  Graphene, a two-dimensional honeycomb lattice of carbon atoms, is of great
interest in (opto)electronics and plasmonics and can be obtained by means of
diverse fabrication techniques, among which chemical vapor deposition (CVD) is
one of the most promising for technological applications. The electronic and
mechanical properties of CVD-grown graphene depend in large part on the
characteristics of the grain boundaries. However, the physical properties of
these grain boundaries remain challenging to characterize directly and
conveniently. Here, we show that it is possible to visualize and investigate
the grain boundaries in CVD-grown graphene using an infrared nano-imaging
technique. We harness surface plasmons that are reflected and scattered by the
graphene grain boundaries, thus causing plasmon interference. By recording and
analyzing the interference patterns, we can map grain boundaries for a large
area CVD-grown graphene film and probe the electronic properties of individual
grain boundaries. Quantitative analysis reveals that grain boundaries form
electronic barriers that obstruct both electrical transport and plasmon
propagation. The effective width of these barriers (~10-20 nm) depends on the
electronic screening and it is on the order of the Fermi wavelength of
graphene. These results uncover a microscopic mechanism that is responsible for
the low electron mobility observed in CVD-grown graphene, and suggest the
possibility of using electronic barriers to realize tunable plasmon reflectors
and phase retarders in future graphene-based plasmonic circuits.


title:
Self-diffusion and cross-diffusion equations: $w^{1,p}$-estimates and
  global existence of smooth solutions

abstract:
  We investigate the global time existence of smooth solutions for the
Shigesada-Kawasaki-Teramoto system of cross-diffusion equations of two
competing species in population dynamics. If there are self-diffusion in one
species and no cross-diffusion in the other, we show that the system has a
unique smooth solution for all time in bounded domains of any dimension. We
obtain this result by deriving global $W^{1,p}$-estimates of
Calder\'{o}n-Zygmund type for a class of nonlinear reaction-diffusion equations
with self-diffusion. These estimates are achieved by employing Caffarelli-Peral
perturbation technique together with a new two-parameter scaling argument.


title: Form factor decomposition of the off-shell four-gluon amplitudes

abstract:
  We show how to use the Bern-Kosower master formula, originally a generating
functional for on-shell gluon matrix elements, to derive well-organized form
factor decompositions of the off-shell one-particle-irreducible N - gluon
vertices. Two such algorithms are presented which can be used for any N, the
first one optimized with respect to the nonabelian gauge invariance, the second
one with respect to transversality. We give explicit results for the three- and
four-gluon cases. The second algorithm in the three-point case reproduces
precisely the well-known Ball-Chiu decomposition, and in the four-point case a
natural generalization thereof. A particularly simple structure emerges in the
N=4 SYM case.


title: Ergodicity of Random Walks on Random DFA

abstract:
  Given a DFA we consider the random walk that starts at the initial state and
at each time step moves to a new state by taking a random transition from the
current state. This paper shows that for typical DFA this random walk induces
an ergodic Markov chain. The notion of typical DFA is formalized by showing
that ergodicity holds with high probability when a DFA is sampled uniformly at
random from the set of all automata with a fixed number of states. We also show
the same result applies to DFA obtained by minimizing typical DFA.


title: Properties of the Eclipsing Double-White Dwarf Binary NLTT 11748

abstract:
  We present high-quality ULTRACAM photometry of the eclipsing detached
double-white dwarf binary NLTT 11748. This system consists of a carbon/oxygen
white dwarf and an extremely-low mass (< 0.2 Msun) helium-core white dwarf in a
5.6 hr orbit. To date such extremely-low mass WDs, which can have thin,
stably-burning outer layers, have been modeled via poorly-constrained
atmosphere and cooling calculations where uncertainties in the detailed
structure can strongly influence the eventual fates of these systems when
mass-transfer begins. With precise (individual precision ~1%) high-cadence (~2
s) multi-color photometry of multiple primary and secondary eclipses spanning
>1.5 yr, we constrain the masses and radii of both objects in the NLTT 11748
system to a statistical uncertainty of a few percent. However, we find that
overall uncertainty in the thickness of the envelope of the secondary
carbon/oxygen white dwarf leads to a larger (~13%) systematic uncertainty in
the primary He WD's mass. Over the full range of possible envelope thicknesses
we find that our primary mass (0.136-0.162 Msun) and surface gravity
(log(g)=6.32-6.38; radii are 0.0423-0.0433 Rsun) constraints do not agree with
previous spectroscopic determinations. We use precise eclipse timing to detect
the Romer delay at 7 sigma significance, providing an additional weak
constraint on the masses and limiting the eccentricity to e*cos(omega)= -4e-5
+/- 5e-5. Finally, we use multi-color data to constrain the secondary's
effective temperature (7600+/-120 K) and cooling age (1.6-1.7 Gyr).


title:
Electrically and mechanically tunable electron spins in silicon carbide
  color centers

abstract:
  The electron spins of semiconductor defects can have complex interactions
with their host, particularly in polar materials like SiC where electrical and
mechanical variables are intertwined. By combining pulsed spin resonance with
ab-initio simulations, we show that spin-spin interactions within SiC neutral
divacancies give rise to spin states with an enhanced Stark effect, sub-10**-6
strain sensitivity, and highly spin-dependent photoluminescence with intensity
contrasts of 15-36%. These results establish SiC color centers as compelling
systems for sensing nanoscale fields.


title: Tamagawa Torsors of an Abelian Variety

abstract:
  For an abelian variety $A$ over a number field $K$, we define the set of
Tamagawa torsors of $A$ at a prime $v$ of $K$ to be the set of principal
homogeneous spaces of $A$ over the completion $K_v$ of $K$ at $v$ that are
split by an unramified extension of $K_v$. In this paper, we study the
arithmetic properties of the Tamagawa torsors.


title: Semi-Supervised Sparse Coding

abstract:
  Sparse coding approximates the data sample as a sparse linear combination of
some basic codewords and uses the sparse codes as new presentations. In this
paper, we investigate learning discriminative sparse codes by sparse coding in
a semi-supervised manner, where only a few training samples are labeled. By
using the manifold structure spanned by the data set of both labeled and
unlabeled samples and the constraints provided by the labels of the labeled
samples, we learn the variable class labels for all the samples. Furthermore,
to improve the discriminative ability of the learned sparse codes, we assume
that the class labels could be predicted from the sparse codes directly using a
linear classifier. By solving the codebook, sparse codes, class labels and
classifier parameters simultaneously in a unified objective function, we
develop a semi-supervised sparse coding algorithm. Experiments on two
real-world pattern recognition problems demonstrate the advantage of the
proposed methods over supervised sparse coding methods on partially labeled
data sets.


title:
Increasing LIGO sensitivity by feedforward subtraction of auxiliary
  length control noise

abstract:
  LIGO, the Laser Interferometer Gravitational-wave Observatory, has been
designed and constructed to measure gravitational wave strain via differential
arm length. The LIGO 4-km Michelson arms with Fabry-Perot cavities have
auxiliary length control servos for suppressing Michelson motion of the
beam-splitter and arm cavity input mirrors, which degrades interferometer
sensitivity. We demonstrate how a post-facto pipeline (AMPS) improves a data
sample from LIGO Science Run 6 with feedforward subtraction. Dividing data into
1024-second windows, we numerically fit filter functions representing the
frequency-domain transfer functions from Michelson length channels into the
gravitational-wave strain data channel for each window, then subtract the
filtered Michelson channel noise (witness) from the strain channel (target). In
this paper we describe the algorithm, assess achievable improvements in
sensitivity to astrophysical sources, and consider relevance to future
interferometry.


title: Perturbative sigma models, elliptic cohomology and the Witten genus

abstract:
  We provide a differential cocycle model for elliptic cohomology with complex
coefficients and use analytic methods to construct a cocycle representative for
the Witten class in this language. Our motivation stems from the conjectural
connection between 2-dimensional field theories and elliptic cohomology
originally due to G. Segal and E. Witten. The specifics of our constructions
are informed by the work of S. Stolz and P. Teichner on super Euclidean field
theories and K. Costello's construction of the Witten genus using perturbative
quantization. As a warm-up, we prove analogous results for supersymmetric
quantum mechanics and K-theory with complex coefficients.


title: Fast Resource Scheduling in HetNets with D2D Support

abstract:
  Resource allocation in LTE networks is known to be an NP-hard problem. In
this paper, we address an even more complex scenario: an LTE-based, 2-tier
heterogeneous network where D2D mode is supported under the network control.
All communications (macrocell, microcell and D2D-based) share the same
frequency bands, hence they may interfere. We then determine (i) the network
node that should serve each user and (ii) the radio resources to be scheduled
for such communication. To this end, we develop an accurate model of the system
and apply approximate dynamic programming to solve it. Our algorithms allow us
to deal with realistic, large-scale scenarios. In such scenarios, we compare
our approach to today's networks where eICIC techniques and proportional
fairness scheduling are implemented. Results highlight that our solution
increases the system throughput while greatly reducing energy consumption. We
also show that D2D mode can effectively support content delivery without
significantly harming macrocells or microcells traffic, leading to an increased
system capacity. Interestingly, we find that D2D mode can be a low-cost
alternative to microcells.


title: Learning Prices for Repeated Auctions with Strategic Buyers

abstract:
  Inspired by real-time ad exchanges for online display advertising, we
consider the problem of inferring a buyer's value distribution for a good when
the buyer is repeatedly interacting with a seller through a posted-price
mechanism. We model the buyer as a strategic agent, whose goal is to maximize
her long-term surplus, and we are interested in mechanisms that maximize the
seller's long-term revenue. We define the natural notion of strategic regret
--- the lost revenue as measured against a truthful (non-strategic) buyer. We
present seller algorithms that are no-(strategic)-regret when the buyer
discounts her future surplus --- i.e. the buyer prefers showing advertisements
to users sooner rather than later. We also give a lower bound on strategic
regret that increases as the buyer's discounting weakens and shows, in
particular, that any seller algorithm will suffer linear strategic regret if
there is no discounting.


title: Picking Planar Edges; or, Drawing a Graph with a Planar Subgraph

abstract:
  Given a graph $G$ and a subset $F \subseteq E(G)$ of its edges, is there a
drawing of $G$ in which all edges of $F$ are free of crossings? We show that
this question can be solved in polynomial time using a Hanani-Tutte style
approach. If we require the drawing of $G$ to be straight-line, and allow at
most one crossing along each edge in $F$, the problem turns out to be as hard
as the existential theory of the real numbers.


title:
Variational approach vs accessible soliton approximation in nonlocal
  nonlinear media

abstract:
  We discuss differences between the variational approach to solitons and the
accessible soliton approximaion in a highly nonlocal nonlinear medium. We
compare results of both approximations by considering the same system of
equations in the same spatial region, under the same boundary conditions. We
also compare these approximations with the numerical solution of the equations.
We find that the variational highly nonlocal approximation provides more
accurate results and as such is more appropriate solution than the accessible
soliton approximation. The accessible soliton model offers a radical
simplification in the treatment of highly nonlocal nonlinear media, with easy
comprehension and convenient parallels to quantum harmonic oscillator, however
with a hefty price tag: a systematic numerical discrepancy of up to 100% with
the numerical results.


title: Observables in Loop Quantum Gravity with a cosmological constant

abstract:
  An open issue in loop quantum gravity (LQG) is the introduction of a
non-vanishing cosmological constant $\Lambda$. In 3d, Chern-Simons theory
provides some guiding lines: $\Lambda$ appears in the quantum deformation of
the gauge group. The Turaev-Viro model, which is an example of spin foam model
is also defined in terms of a quantum group. By extension, it is believed that
in 4d, a quantum group structure could encode the presence of $\Lambda\neq0$.
In this article, we introduce by hand the quantum group
$\mathcal{U}_{q}(\mathfrak{su}(2))$ into the LQG framework, that is we deal
with $\mathcal{U}_{q}(\mathfrak{su}(2))$-spin networks. We explore some of the
consequences, focusing in particular on the structure of the observables. Our
fundamental tools are tensor operators for $\mathcal{U}_{q}(\mathfrak{su}(2))$.
We review their properties and give an explicit realization of the spinorial
and vectorial ones. We construct the generalization of the U($n$) formalism in
this deformed case, which is given by the quantum group
$\mathcal{U}_{q}(\mathfrak{u}(n))$. We are then able to build geometrical
observables, such as the length, area or angle operators ... We show that these
operators characterize a quantum discrete hyperbolic geometry in the 3d LQG
case. Our results confirm that the use of quantum group in LQG can be a tool to
introduce a non-zero cosmological constant into the theory.


title: Characteristics of Universal Embezzling Families

abstract:
  We derive properties of general universal embezzling families for bipartite
embezzlement protocols, where any pure state can be converted to any other
without communication, but in the presence of the embezzling family. Using this
framework, we exhibit various families inequivalent to that proposed by van Dam
and Hayden. We suggest a possible improvement and present detail numerical
analysis.


title:
On homogenized conductivity and fractal structure in a high contrast
  continuum percolation model

abstract:
  In the previous article (S. Matsutani and Y. Shimosako and Y. Wang, Physica A
\bf{391} (2012) 5802-5809) we numerically investigated an electric potential
problem with high contrast local conductivities ($\gamma_0$ and $\gamma_1$,
$0<\gamma_0 \ll \gamma_1$) for a two-dimensional continuum percolation model
(CPM). As numerical results, we showed there that the equipotential curves
exhibit the fractal structure around the threshold $p_c$ and gave an
approximated curve representing a relation between the homogenized conductivity
and the volume fraction $p$ over $[p_c,1]$. In this article, using the duality
of the conductivities and the quasi-harmonic properties, we re-investigate
these topics to improve these results. We show that at $\gamma_0\to0$, the
quasi-harmonic potential problem in CPM is quasiconformally equivalent to a
random slit problem, which leads us to an observation between the conformal
property and the fractal structure at the threshold. Further we extend the
domain $[p_c,1]$ of the approximated curve to $[0,1]$ based on the these
results, which is partially generalized to three dimensional case. These curves
represent well the numerical results of the conductivities.


title:
Estimating the Ratio of Two Functions in a Nonparametric Regression
  Model

abstract:
  Due to measurement noise, a common problem in in various fields is how to
estimate the ratio of two functions. We consider this problem of estimating the
ratio of two functions in a nonparametric regression model. Assuming the noise
is normally distributed, this is equivalent to estimating the ratio of the
means of two normally distributed random variables. We identified a consistent
estimator that gives the mean squared loss of order $O(1/n)$ ($n$ is the sample
size) when conditioned on a highly probable event. We also present our result
applied to both the real data from EAPS and on simulated data, confirming our
theoretical results.


title: Lower bounds for the truncated Hilbert transform

abstract:
  Given two intervals $I, J \subset \mathbb{R}$, we ask whether it is possible
to reconstruct a real-valued function $f \in L^2(I)$ from knowing its Hilbert
transform $Hf$ on $J$. When neither interval is fully contained in the other,
this problem has a unique answer (the nullspace is trivial) but is severely
ill-posed. We isolate the difficulty and show that by restricting $f$ to
functions with controlled total variation, reconstruction becomes stable. In
particular, for functions $f \in H^1(I)$, we show that $$ \|Hf\|_{L^2(J)} \geq
c_1 \exp{\left(-c_2 \frac{\|f_x\|_{L^2(I)}}{\|f\|_{L^2(I)}}\right)} \| f
\|_{L^2(I)} ,$$ for some constants $c_1, c_2 > 0$ depending only on $I, J$.
This inequality is sharp, but we conjecture that $\|f_x\|_{L^2(I)}$ can be
replaced by $\|f_x\|_{L^1(I)}$.


title: Transport of Particles in Liquid Crystals

abstract:
  Colloidal particles in a liquid crystal (LC) behave very differently from
their counterparts in isotropic fluids. Elastic nature of the orientational
order and surface anchoring of the director cause long-range anisotropic
interactions and lead to the phenomenon of levitation. The LC environment
enables new mechanisms of particle transport that are reviewed in this work.
Among them the motion of particles caused by gradients of the director, and
effects in the electric field: backflow powered by director reorientations,
dielectrophoresis in LC with varying dielectric permittivity and LC-enabled
nonlinear electrophoresis with velocity that depends on the square of the
applied electric field and can be directed differently from the field
direction.


title: A complete degeneration of the moduli of $G$-bundles on a curve

abstract:
  For a semi simple group G it is known the moduli stack of principal G-bundles
over a fixed nodal curve is not complete. Finding a completion requires
compactifying the group G. However it was shown in [34] that this is not
sufficient to complete the moduli stack over a family of curves. In this paper
I describe how to use an embedding of the loop group LG to provide a completion
of the stack of G-bundles over a one dimensional family of curves degenerating
to a nodal curve. The completion comes with a modular interpretation inspired
by the work of Gieseker, Seshadri, Kausz and Thaddeus and Martens.


title: Random Residue Sequences and the Number Theoretic Hilbert Transform

abstract:
  This paper presents random residue sequences derived from the number
theoretic Hilbert (NHT) transform and their correlation properties. The
autocorrelation of a NHT derived sequence is zero for all non-zero shifts which
illustrates that these are self-orthogonal sequences. The cross correlation
function between two sequences may be computed with respect to the moduli of
the either sequence. There appears to be some kind of an inverse qualitative
relationship between these two different computations for many sets of residue
sequences.


title:
Testing against a linear regression model using ideas from
  shape-restricted estimation

abstract:
  A formal likelihood ratio hypothesis test for the validity of a parametric
regression function is proposed, using a large-dimensional, nonparametric
double cone alternative. For example, the test against a constant function uses
the alternative of increasing or decreasing regression functions, and the test
against a linear function uses the convex or concave alternative. The proposed
test is exact, unbiased and the critical value is easily computed. The power of
the test increases to one as the sample size increases, under very mild
assumptions -- even when the alternative is mis-specified. That is, the power
of the test converges to one for any true regression function that deviates (in
a non-degenerate way) from the parametric null hypothesis. We also formulate
tests for the linear versus partial linear model, and consider the special case
of the additive model. Simulations show that our procedure behaves well
consistently when compared with other methods. Although the alternative fit is
non-parametric, no tuning parameters are involved.


title: Quantum chromatic numbers via operator systems

abstract:
  We define several new types of quantum chromatic numbers of a graph and
characterise them in terms of operator system tensor products. We establish
inequalities between these chromatic numbers and other parameters of graphs
studied in the literature and exhibit a link between them and non-signalling
correlation boxes.


title:
Quantum Spin-$1$ Anisotropic Ferromagnetic Heisenberg Model in a Crystal
  Field: A Variational Approach

abstract:
  A variational approach based on Bogoliubov inequality for the free energy is
employed in order to treat the quantum spin-$1$ anisotropic ferromagnetic
Heisenberg model in the presence of a crystal field. Within the Bogoliubov
scheme an improved pair approximation has been used. The temperature dependent
thermodynamic functions have been obtained and provide much better results than
the previous simple mean-field scheme. In one dimension, which is still
non-integrable for quantum spin-$1$, we get the exact results in the classical
limit, or near-exact results in the quantum case, for the free energy,
magnetization and quadrupole moment, as well for the transition temperature. In
two and three dimensions the corresponding global phase diagrams have been
obtained as a function of the parameters of the Hamiltonian. First-order
transition lines, second-order transition lines, tricritical and tetracritical
points, and critical endpoints have been located through the analysis of the
minimum of the Helmholtz free energy and a Landau like expansion in the
approximated free energy. Only first-order quantum transitions have been found
at zero temperature. Limiting cases, such as isotropic Heisenberg, Blume-Capel
and Ising models have been analyzed and compared to previous results obtained
from other analytical approaches as well as from Monte Carlo simulations.


title:
On modifications of Reichenbach's principle of common cause in light of
  Bell's theorem

abstract:
  Bell's 1964 theorem causes a severe problem for the notion that correlations
require explanation, encapsulated in Reichenbach's Principle of Common Cause.
Despite being a hallmark of scientific thought, dropping the principle has been
widely regarded as a much less bitter medicine than the perceived
alternative---dropping relativistic causality. Recently, however, some authors
have proposed that modified forms of Reichenbach's principle could be
maintained even with relativistic causality. Here we break down Reichenbach's
principle into two independent assumptions---the Principle of Common Cause
proper, and Factorisation of Probabilities. We show how Bell's theorem can be
derived from these two assumptions plus Relativistic Causality and the Law of
Total Probability for actual events, and we review proposals to drop each of
these assumptions in light of the theorem. In particular, we show that the
non-commutative common causes of Hofer-Szabo and Vecsernyes fail to have an
analogue of the notion that the common causes can explain the observed
correlations. Moreover, we show that their definition can be satisfied
trivially by any quantum product state for any quantum correlations. We also
discuss how the conditional states approach of Leifer and Spekkens fares in
this regard.


title:
Channel, Phase Noise, and Frequency Offset in OFDM Systems: Joint
  Estimation, Data Detection, and Hybrid Cramer-Rao Lower Bound

abstract:
  Oscillator phase noise (PHN) and carrier frequency offset (CFO) can adversely
impact the performance of orthogonal frequency division multiplexing (OFDM)
systems, since they can result in inter carrier interference and rotation of
the signal constellation. In this paper, we propose an expectation conditional
maximization (ECM) based algorithm for joint estimation of channel, PHN, and
CFO in OFDM systems. We present the signal model for the estimation problem and
derive the hybrid Cramer-Rao lower bound (HCRB) for the joint estimation
problem. Next, we propose an iterative receiver based on an extended Kalman
filter for joint data detection and PHN tracking. Numerical results show that,
compared to existing algorithms, the performance of the proposed ECM-based
estimator is closer to the derived HCRB and outperforms the existing estimation
algorithms at moderate-to-high signal-to-noise ratio (SNR). In addition, the
combined estimation algorithm and iterative receiver are more computationally
efficient than existing algorithms and result in improved average uncoded and
coded bit error rate (BER) performance.


title:
$F_4$ Quantum Integrable, rational and trigonometric models:
  space-of-orbits view

abstract:
  Algebraic-rational nature of the four-dimensional, $F_4$-invariant integrable
quantum Hamiltonians, both rational and trigonometric, is revealed and
reviewed. It was shown that being written in $F_4$ Weyl invariants, polynomial
and exponential, respectively, both similarity-transformed Hamiltonians are in
algebraic form, they are quite similar the second order differential operators
with polynomial coefficients; the flat metric in the Laplace-Beltrami operator
has polynomial (in invariants) matrix elements. Their potentials are calculated
for the first time: they are meromorphic (rational) functions with
singularities at the boundaries of the configuration space. Ground state
eigenfunctions are algebraic functions in a form of polynomials in some
degrees. Both Hamiltonians preserve the same infinite flag of polynomial spaces
with characteristic vector $(1, 2, 2, 3)$, it manifests exact solvability. A
particular integral common for both models is derived. The first polynomial
eigenfunctions are presented explicitly.


title: Lone Axes in Outer Space

abstract:
  Handel and Mosher define the axis bundle for a fully irreducible outer
automorphism in "Axes in Outer Space." In this paper we give a necessary and
sufficient condition for the axis bundle to consist of a unique periodic fold
line. As a consequence, we give a setting, and means for identifying in this
setting, when two elements of an outer automorphism group $Out(F_r)$ have
conjugate powers.


title: Note on the subgraph component polynomial

abstract:
  Tittmann, Averbouch and Makowsky [P. Tittmann, I. Averbouch, J.A. Makowsky,
The enumeration of vertex induced subgraphs with respect to the number of
components, European Journal of Combinatorics, 32 (2011) 954-974], introduced
the subgraph component polynomial $Q(G;x,y)$ which counts the number of
connected components in vertex induced subgraphs. It contains much of the
underlying graph's structural information, e.g. the order, the size, the
independence number. We show that there are several other graph invariants,
like the connectivity, the number of cycles of length four in a regular
bipartite graph, are determined by the subgraph component polynomial. Using the
obtained results, we find several well-known families of graphs are determined
by $Q(G;x,y)$: paths, cycles, tadpole graphs, complete bipartite graphs,
friendship graphs, book graphs and hypercubes. Moreover, we study the
distinguish power and find some simple graphs which are not distinguished by
the subgraph component polynomial but distinguished by the Tutte polynomial and
the character polynomial. These are answers to three questions concerning the
subgraph component polynomial proposed by Tittmann et al.


title: Agriculture driving male expansion in Neolithic Time

abstract:
  The emergence of agriculture is suggested to have driven extensive human
population growths. However, genetic evidence from maternal mitochondrial
genomes suggests major population expansions began before the emergence of
agriculture. Therefore, role of agriculture that played in initial population
expansions still remains controversial. Here, we analyzed a set of globally
distributed whole Y chromosome and mitochondrial genomes of 526 male samples
from 1000 Genome Project. We found that most major paternal lineage expansions
coalesced in Neolithic Time. The estimated effective population sizes through
time revealed strong evidence for 10- to 100-fold increase in population growth
of males with the advent of agriculture. This sex-biased Neolithic expansion
might result from the reduction in hunting-related mortality of males.