title:
Structural and optical investigations of the iron-chalcogenide
  superconductor Fe$_{1.03}$Se$_{0.5}$Te$_{0.5}$ under high pressure

abstract:
  Iron-chalcogenide superconductor Fe$_{1.03}$Se$_{0.5}$Te$_{0.5}$ has been
investigated under high pressure using synchrotron based x-ray diffraction and
mid-infrared reflectance measurements at room temperature. Pressure dependence
of the superconducting transition temperature (T$_c$) of the same sample has
been determined by temperature-dependent resistance measurements up to 10 GPa.
Although the high pressure orthorhombic phase ($\textit{Pbnm}$) starts emerging
at 4 GPa, structural transition becomes clearly observable above 10 GPa. A
strong correlation is observed between the Fe(Se,Te)$_{4}$ tetrahedral
deformation in the tetragonal phase ($\textit{P4/nmm}$) and the sharp rise of
T$_c$ up to $\sim$4 GPa, above which T$_c$ is found to be almost pressure
independent at least up to 10 GPa. A subtle structural modification of the
tetragonal phase is noticed above 10 GPa, suggesting a structural transition
with possible Fe$^{2+}$ spin-state transition. The evolution with pressure of
the optical conductivity shows that the Drude term increases systematically
with pressure up to 5.4 GPa, indicating the evolution of the tetragonal phase
towards a conventional metallic state. At further higher pressures the Drude
term reduces drastically implying a poor metallic character of the high
pressure orthorhombic phase. Our results suggest that occurrence of large onset
T$_c$ above 4 GPa is due to a systematic increase of high pressure orthorhombic
phase fraction.


title: The Hadronic Final State at HERA

abstract:
  The hadronic final state in electron-proton collisions at HERA has provided a
rich testing ground for development of the theory of the strong force, QCD. In
this review, over 200 publications from the H1 and ZEUS Collaborations are
summarised. Short distance physics, the measurement of processes at high energy
scales, has provided rigorous tests of perturbative QCD and constrained the
structure of the proton as well as allowing precise measurements of the strong
coupling constant to be made. Non-perturbative or low energy processes have
also been investigated and results on hadronisation interpreted together with
those from other experiments. Searches for exotic QCD objects, such as
pentaquarks, glueballs and instantons have been performed. The subject of
diffraction has been re-invigorated through its precise measurement, such that
it can now be described by perturbative QCD. After discussion of HERA, the H1
and ZEUS detectors and the techniques used to reconstruct differing hadronic
final states, the above subject areas are elaborated. The major achievements
are then condensed further in a final section summarising what has been
learned.


title:
Equations of motion in gravity theories with nonminimal coupling: a
  loophole to detect torsion macroscopically?

abstract:
  We derive multipolar equations of motion for gravitational theories with
general nonminimal coupling in spacetimes admitting torsion. Our very general
findings allow for the systematic testing of whole classes of theories by means
of extended test bodies. One peculiar feature of certain subclasses of
nonminimal theories turns out to be their sensitivity to post-Riemannian
spacetime structures even in experiments without microstructured test matter.


title: Drawing Planar Graphs with a Prescribed Inner Face

abstract:
  Given a plane graph $G$ (i.e., a planar graph with a fixed planar embedding)
and a simple cycle $C$ in $G$ whose vertices are mapped to a convex polygon, we
consider the question whether this drawing can be extended to a planar
straight-line drawing of $G$. We characterize when this is possible in terms of
simple necessary conditions, which we prove to be sufficient. This also leads
to a linear-time testing algorithm. If a drawing extension exists, it can be
computed in the same running time.


title:
Production of kshort, kstar(892)and phi(1020) in minimum bias events and
  kshort and lambda in jets in pbar p collisions at sqrt(s)=1.96 TeV

abstract:
  We report measurements of the inclusive transverse momentum pT distribution
of centrally produced kshort, kstar(892), and phi(1020) mesons up to pT = 10
GeV/c in minimum-bias events, and kshort and lambda particles up to pT = 20
GeV/c in jets with transverse energy between 25 GeV and 160 GeV in pbar p
collisions. The data were taken with the CDF II detector at the Fermilab
Tevatron at sqrt(s) = 1.96 TeV. We find that as pT increases, the pT slopes of
the three mesons (kshort, kstar, and phi) are similar, and the ratio of lambda
to kshort as a function of pT in minimum-bias events becomes similar to the
fairly constant ratio in jets at pT ~ 5 GeV/c. This suggests that the particles
with pT >~ 5 GeV/c in minimum-bias events are from soft jets, and that the pT
slope of particles in jets is insensitive to light quark flavor (u, d, or s)
and to the number of valence quarks. We also find that for pT <~ 4 GeV
relatively more lambda baryons are produced in minimum-bias events than in
jets.


title: Objective Information Theory: A Sextuple Model and 9 Kinds of Metrics

abstract:
  In the contemporary era, the importance of information is undisputed, but
there has never been a common understanding of information, nor a unanimous
conclusion to the researches on information metrics. Based on the previous
studies, this paper analyzes the important achievements in the researches of
the properties and metrics of information as well as their main
insufficiencies, and explores the essence and connotation, the mathematical
expressions and other basic problems related to information. On the basis of
the understanding of the objectivity of information, it proposes the
definitions and a Sextuple model of information; discusses the basic properties
of information, and brings forward the definitions and mathematical expressions
of nine kinds of metrics of information, i.e., extensity, detailedness,
sustainability, containability, delay, richness, distribution, validity and
matchability. Through these, this paper establishes a basic theory frame of
Objective Information Theory to support the analysis and research on
information and information system systematically and comprehensively.


title:
Hole propagation in the Kitaev-Heisenberg model: From quasiparticles in
  quantum Neel states to non-Fermi liquid in the Kitaev phase

abstract:
  We explore with exact diagonalization the propagation of a single hole in
four magnetic phases of the t-J-like Kitaev-Heisenberg model on a honeycomb
lattice: the Neel antiferromagnetic, stripe, zigzag and Kitaev spin-liquid
phase. We find coherent propagation of spin-polaron quasiparticles in the
antiferromagnetic phase by a similar mechanism as in the $t$-$J$ model for
high-$T_c$ cuprates. In the stripe and zigzag phases clear quasiparticles
features appear in spectral functions of those propagators where holes are
created and annihilated on one sublattice, while they remain largely {\it
hidden} in those spectral functions that correspond to photoemission
experiments. As the most surprising result, we find a totally incoherent
spectral weight distribution for the spectral function of a hole moving in the
Kitaev spin-liquid phase in the strong coupling regime relevant for iridates.
At intermediate coupling the finite systems calculation reveals a well defined
quasiparticle at the $\Gamma$ point, however, we find that the gapless spin
excitations wipe out quasiparticles at finite momenta. Also for this more
subtle case we conclude that in the thermodynamic limit the lightly doped
Kitaev liquid phase does not support quasiparticle states in the neighborhood
of $\Gamma$, and therefore yields a {\it non-Fermi liquid}, contrary to earlier
suggestions based on slave-boson studies. These observations are supported by
the presented study of the dynamic spin-structure factor for the Kitaev spin
liquid regime.


title:
Utilization of Noise-Only Samples in Array Processing With Prior
  Knowledge

abstract:
  For array processing, we consider the problem of estimating signals of
interest, and their directions of arrival (DOA), in unknown colored noise
fields. We develop an estimator that efficiently utilizes a set of noise-only
samples and, further, can incorporate prior knowledge of the DOAs with varying
degrees of certainty. The estimator is compared with state of the art
estimators that utilize noise-only samples, and the Cram\'{e}r-Rao bound,
exhibiting improved performance for smaller sample sets and in poor signal
conditions.


title:
Suppression of bulk conductivity in InAs/GaSb broken gap composite
  quantum wells

abstract:
  The two-dimensional topological insulator state in InAs/GaSb quantum wells
manifests itself by topologically protected helical edge channel transport
relying on an insulating bulk. This work investigates a way of suppressing bulk
conductivity by using gallium source materials of different degrees of impurity
concentrations. While highest-purity gallium is accompanied by clear conduction
through the sample bulk, intentional impurity incorporation lead to a bulk
resistance over 1 M\Omega. This resistance was found to be independent of
applied magnetic fields. Ultra high electron mobilities for GaAs/AlGaAs
structures fabricated in a molecular beam epitaxy system used for the growth of
Sb-based samples are reported.


title:
Using Coordinated Observations in Polarised White Light and Faraday
  Rotation to Probe the Spatial Position and Magnetic Field of an
  Interplanetary Sheath

abstract:
  Coronal mass ejections (CMEs) can be continuously tracked through a large
portion of the inner heliosphere by direct imaging in visible and radio
wavebands. White-light (WL) signatures of solar wind transients, such as CMEs,
result from Thomson scattering of sunlight by free electrons, and therefore
depend on both the viewing geometry and the electron density. The Faraday
rotation (FR) of radio waves from extragalactic pulsars and quasars, which
arises due to the presence of such solar wind features, depends on the
line-of-sight magnetic field component $B_\parallel$, and the electron density.
To understand coordinated WL and FR observations of CMEs, we perform forward
magnetohydrodynamic modelling of an Earth-directed shock and synthesise the
signatures that would be remotely sensed at a number of widely distributed
vantage points in the inner heliosphere. Removal of the background solar wind
contribution reveals the shock-associated enhancements in WL and FR. While the
efficiency of Thomson scattering depends on scattering angle, WL radiance $I$
decreases with heliocentric distance $r$ roughly according to the expression $I
\propto r^{-3}$. The sheath region downstream of the Earth-directed shock is
well viewed from the L4 and L5 Lagrangian points, demonstrating the benefits of
these points in terms of space weather forecasting. The spatial position of the
main scattering site $\mathbf{r}_{\rm sheath}$ and the mass of plasma at that
position $M_{\rm sheath}$ can be inferred from the polarisation of the
shock-associated enhancement in WL radiance. From the FR measurements, the
local $B_{\parallel {\rm sheath}}$ at $\mathbf{r}_{\rm sheath}$ can then be
estimated. Simultaneous observations in polarised WL and FR can not only be
used to detect CMEs, but also to diagnose their plasma and magnetic field
properties.


title:
Characterization of gradient Young measures generated by homeomorphisms
  in the plane

abstract:
  We characterize Young measures generated by gradients of bi-Lipschitz
orientation-preserving maps in the plane. This question is motivated by
variational problems in nonlinear elasticity where the orientation preservation
and injectivity of the admissible deformations are key requirements. These
results enable us to derive new weak$^*$ lower semicontinuity results for
integral functionals depending on gradients. As an application, we show the
existence of a minimizer for an integral functional with nonpolyconvex energy
density among bi-Lipschitz homeomorphisms.


title: A pricing measure to explain the risk premium in power markets

abstract:
  In electricity markets, it is sensible to use a two-factor model with mean
reversion for spot prices. One of the factors is an Ornstein-Uhlenbeck (OU)
process driven by a Brownian motion and accounts for the small variations. The
other factor is an OU process driven by a pure jump L\'evy process and models
the characteristic spikes observed in such markets. When it comes to pricing, a
popular choice of pricing measure is given by the Esscher transform that
preserves the probabilistic structure of the driving L\'evy processes, while
changing the levels of mean reversion. Using this choice one can generate
stochastic risk premiums (in geometric spot models) but with
(deterministically) changing sign. In this paper we introduce a pricing change
of measure, which is an extension of the Esscher transform. With this new
change of measure we also can slow down the speed of mean reversion and
generate stochastic risk premiums with stochastic non constant sign, even in
arithmetic spot models. In particular, we can generate risk profiles with
positive values in the short end of the forward curve and negative values in
the long end. Finally, our pricing measure allows us to have a stationary spot
dynamics while still having randomly fluctuating forward prices for contracts
far from maturity.


title:
Localized orthogonal decomposition techniques for boundary value
  problems

abstract:
  In this paper we propose a Local Orthogonal Decomposition method (LOD) for
elliptic partial differential equations with inhomogeneous Dirichlet- and
Neumann boundary conditions. For this purpose, we present new boundary
correctors which preserve the common convergence rates of the LOD, even if the
boundary condition has a rapidly oscillating fine scale structure. We prove a
corresponding a-priori error estimate and present numerical experiments. We
also demonstrate numerically that the method is reliable with respect to thin
conductivity channels in the diffusion matrix. Accurate results are obtained
without resolving these channels by the coarse grid and without using patches
that contain the channels.


title: Vertex-pursuit in random directed acyclic graphs

abstract:
  We examine a dynamic model for the disruption of information flow in
hierarchical social networks by considering the vertex-pursuit game Seepage
played in directed acyclic graphs (DAGs). In Seepage, agents attempt to block
the movement of an intruder who moves downward from the source node to a sink.
The minimum number of such agents required to block the intruder is called the
green number. We propose a generalized stochastic model for DAGs with given
expected total degree sequence. Seepage and the green number is analyzed in
stochastic DAGs in both the cases of a regular and power law degree sequence.
For each such sequence, we give asymptotic bounds (and in certain instances,
precise values) for the green number.


title: High dimensional Sparse Gaussian Graphical Mixture Model

abstract:
  This paper considers the problem of networks reconstruction from
heterogeneous data using a Gaussian Graphical Mixture Model (GGMM). It is well
known that parameter estimation in this context is challenging due to large
numbers of variables coupled with the degeneracy of the likelihood. We propose
as a solution a penalized maximum likelihood technique by imposing an $l_{1}$
penalty on the precision matrix. Our approach shrinks the parameters thereby
resulting in better identifiability and variable selection. We use the
Expectation Maximization (EM) algorithm which involves the graphical LASSO to
estimate the mixing coefficients and the precision matrices. We show that under
certain regularity conditions the Penalized Maximum Likelihood (PML) estimates
are consistent. We demonstrate the performance of the PML estimator through
simulations and we show the utility of our method for high dimensional data
analysis in a genomic application.


title:
The $\gamma p \to n a^+_2(1320) \to n \rho^0 \pi^+$ reactions within an
  effective Lagrangian approach

abstract:
  We investigate the $a_2(1320)$ meson photon production in the $\gamma p \to n
a^+_2(1320)$ and $\gamma p \to n \rho^0 \pi^+$ reactions within the effective
Lagrangian method. For $\gamma p \to n a^+_2(1320)$ reaction, by considering
the contributions only from the $t-$channel $\pi^+$ exchange, we get a fairly
good description of the current experimental total cross section data. We also
studied the $\gamma p \to n \rho^0 \pi^+$ reaction, which mainly contribute to
the $\gamma p \to n \pi^+ \pi^+ \pi^-$ reaction. The latter reaction has
measured by the CLAS Collaboration. The total cross sections, invariant mass
distribution, and the Dalitz Plot of $\gamma p \to n \rho^0 \pi^+$ reaction are
shown, which can be tested by future experiments.


title: Axioms for graph clustering quality functions

abstract:
  We investigate properties that intuitively ought to be satisfied by graph
clustering quality functions, that is, functions that assign a score to a
clustering of a graph. Graph clustering, also known as network community
detection, is often performed by optimizing such a function. Two axioms
tailored for graph clustering quality functions are introduced, and the four
axioms introduced in previous work on distance based clustering are
reformulated and generalized for the graph setting. We show that modularity, a
standard quality function for graph clustering, does not satisfy all of these
six properties. This motivates the derivation of a new family of quality
functions, adaptive scale modularity, which does satisfy the proposed axioms.
Adaptive scale modularity has two parameters, which give greater flexibility in
the kinds of clusterings that can be found. Standard graph clustering quality
functions, such as normalized cut and unnormalized cut, are obtained as special
cases of adaptive scale modularity.
  In general, the results of our investigation indicate that the considered
axiomatic framework covers existing `good' quality functions for graph
clustering, and can be used to derive an interesting new family of quality
functions.


title: Consistency Analysis of Sensor Data Distribution

abstract:
  In this paper we analyze the probability of consistency of sensor data
distribution systems (SDDS), and determine suitable evaluation models. This
problem is typically difficult, since a reliable model taking into account all
parameters and processes which affect the system consistency is unavoidably
very complex. The simplest candidate approach consists of modeling the state
sojourn time, or holding time, as memoryless, and resorting to the well known
solutions of Markovian processes. Nevertheless, it may happen that this
approach does not fit with some working conditions. In particular, the correct
modeling of the SDDS dynamics requires the introduction of a number of
parameters, such as the packet transfer time or the packet loss probability,
the value of which may determine the suitability of unsuitability of the
Markovian model. Candidate alternative solutions include the Erlang phase-type
approximation of nearly constant state holding time and a more refined model to
account for overlapping events in semi-Markov processes.


title: Meyniel's conjecture on the cop number: a survey

abstract:
  Meyniel's conjecture is one of the deepest open problems on the cop number of
a graph. It states that for a connected graph $G$ of order $n,$ $c(G) =
O(\sqrt{n}).$ While largely ignored for over 20 years, the conjecture is
receiving increasing attention. We survey the origins of and recent
developments towards the solution of the conjecture. We present some new
results on Meyniel extremal families containing graphs of order $n$ satisfying
$c(G) \ge d\sqrt{n},$ where $d$ is a constant.


title: Finite volume effects in low-energy neutron-deuteron scattering

abstract:
  We present a lattice calculation of neutron-deuteron scattering at very low
energies and investigate in detail the impact of the topological finite-volume
corrections. Our calculations are carried out in the framework of pionless
effective field theory at leading order in the low-energy expansion. Using
lattice sizes and a lattice spacing comparable to those employed in nuclear
lattice simulations, we find that the topological volume corrections must be
taken into account in order to obtain correct results for the neutron-proton
S-wave scattering lengths.


title: Enhanced diffusion of tracer particles in dilute bacterial suspensions

abstract:
  Swimming bacteria create long-range velocity fields that stir a large volume
of fluid and move around passive particles dispersed in the fluid. Recent
experiments and simulations have shown that long-time mean-squared displacement
of passive particles in a bath of swimming bacteria exhibits diffusive
behaviour with the effective diffusion coefficient significantly larger than
its thermal counterpart. Comprehensive theoretical prediction of this effective
diffusion coefficient and understanding of the enhancement mechanism remain a
challenge. Here, we adapt the kinetic theory by Lin et al., J. Fluid Mech. 669,
167 (2011) developed for 'squirmers' to the bacterial case to quantitatively
predict enhanced diffusivity of tracer particles in dilute two- and
three-dimensional suspensions of swimming bacteria. We demonstrate that the
effective diffusion coefficient is a product of the bacterial number density,
their swimming speed, a geometric factor characterising the velocity field
created by a single bacterium, and a numerical factor. We show that the
numerical factor is, in fact, a rather strong function of the system
parameters, most notably the run length of the bacteria, and that these
dependencies have to be taken into account to quantitatively predict the
enhanced diffusivity. We perform molecular-dynamics-type simulations to confirm
the conclusions of the kinetic theory. Our results are in a good agreement with
the values of enhanced diffusivity measured in recent two- and
three-dimensional experiments.


title: Models of on-line social networks

abstract:
  We present a deterministic model for on-line social networks (OSNs) based on
transitivity and local knowledge in social interactions. In the Iterated Local
Transitivity (ILT) model, at each time-step and for every existing node $x$, a
new node appears which joins to the closed neighbour set of $x.$ The ILT model
provably satisfies a number of both local and global properties that were
observed in OSNs and other real-world complex networks, such as a densification
power law, decreasing average distance, and higher clustering than in random
graphs with the same average degree. Experimental studies of social networks
demonstrate poor expansion properties as a consequence of the existence of
communities with low number of inter-community edges. Bounds on the spectral
gap for both the adjacency and normalized Laplacian matrices are proved for
graphs arising from the ILT model, indicating such bad expansion properties.
The cop and domination number are shown to remain the same as the graph from
the initial time-step $G_0$, and the automorphism group of $G_0$ is a subgroup
of the automorphism group of graphs generated at all later time-steps. A
randomized version of the ILT model is presented, which exhibits a tuneable
densification power law exponent, and maintains several properties of the
deterministic model.


title: $Z'$-ino-driven Electroweak Baryogenesis in the UMSSM

abstract:
  The viable window to electroweak baryogenesis in a supersymmetric $U(1)'$
model is studied in light of the 126 GeV Higgs boson. To investigate the
decoupling of the sphaleron process in the broken phase, we evaluate the
sphaleron rate and order of the electroweak phase transition. In this model,
the electroweak phase transition is strongly first order due to the
doublet-singlet Higgs mixing. Consequently, for typical parameter sets the $Z'$
boson has to be lighter than (150-300) GeV and thus leptophobic to be
consistent with the collider bounds. We also estimate the baryon asymmetry of
the universe based on the closed-time-path formalism, and find that the
CP-violating source term fueled by the $Z'$-ino can generate sufficient baryon
asymmetry.


title: Some Notes on Compact Sets in Soft Metric Spaces

abstract:
  The first aim of this study is to define soft sequential compact metric
spaces and to investigate some important theorems on soft sequential compact
metric space. Second is to introduce net and totally bounded soft metric space
and study properties of this space. Third is to define Lebesque number and soft
uniformly continuous mapping and investigate some theorems in detail.


title: Gauss-Bonnet boson stars

abstract:
  We construct boson stars in (4+1)-dimensional Gauss-Bonnet gravity. We study
the properties of the solutions in dependence on the coupling constants and
investigate these in detail. While the "thick wall" limit is independent of the
value of the Gauss-Bonnet coupling, we find that the spiraling behaviour
characteristic for boson stars in standard Einstein gravity disappears for
large enough values of the Gauss-Bonnet coupling. Our results show that in this
case the scalar field can not have arbitrarily high values at the center of the
boson star and that it is hence impossible to reach the "thin wall" limit.
Moreover, for large enough Gauss-Bonnet coupling we find a unique relation
between the mass and the radius (qualitatively similar to those of neutron
stars) which is not present in the Einstein gravity limit.


title:
Self-Sealing Shells: Blowouts and Blisters on the Surfaces of Leaky
  Wind-Blown-Bubbles and Supernova Remnants

abstract:
  Blowouts can occur when a dense shell confining hot, high pressure, gas
ruptures. The venting gas inflates a blister on the surface of the shell. Here
we examine the growth of such blisters on the surfaces of wind-blown-bubbles
(WBBs) and supernova remnants (SNRs) due to shell rupture caused by the
Vishniac instability. On WBBs the maximum relative size of the blister
(R_bstall/R) is found to grow linearly with time, but in many cases the blister
radius will not exceed 20 per cent of the bubble radius. Thus blowouts
initiated by the Vishniac instability are unlikely to have a major effect on
the global dynamics and properties of the bubble. The relative size of blisters
on SNRs is even smaller than on WBBs, with blisters only growing to a radius
comparable to the thickness of the cold shell of SNRs. The small size of the
SNR blowouts is, however, in good agreement with observations of blisters in
the Vela SNR. The difference in relative size between WBB and SNR blisters is
due to the much higher speed at which gas vents out of WBBs, which translates
into a greater energy flux through a rupture of a given size from interior gas
of a given pressure. Larger blisters are possible if shell ruptures are bigger
than expected.
  We expect the observed velocity structure of SNR shells to be affected by the
presence of blisters until the shell is no longer susceptible to ruptures,
since the initial expansion of blisters is faster than the ongoing expansion of
the shell.


title: Cosmology with matter diffusion

abstract:
  We construct a viable cosmological model based on velocity diffusion of
matter particles. In order to ensure the conservation of the total
energy-momentum tensor in the presence of diffusion, we include a cosmological
scalar field $\phi$ which we identify with the dark energy component of the
Universe. The model is characterized by only one new degree of freedom, the
diffusion parameter $\sigma$. The standard $\Lambda$CDM model can be recovered
by setting $\sigma=0$. If diffusion takes place ($\sigma >0$) the dynamics of
the matter and of the dark energy fields are coupled. We argue that the
existence of a diffusion mechanism in the Universe can serve as a theoretical
motivation for interacting models. We constrain the background dynamics of the
diffusion model with Supernovae, H(z) and BAO data. We also perform a
perturbative analysis of this model in order to understand structure formation
in the Universe. We calculate the impact of diffusion both on the CMB spectrum,
with particular attention to the integrated Sachs-Wolfe signal, and on the
matter power spectrum $P(k)$. The latter analysis places strong constraints on
the magnitude of the diffusion mechanism but does not rule out the model.


title: Superrosy fields and valuations

abstract:
  We prove that every non-trivial valuation on an infinite superrosy field of
positive characteristic has divisible value group and algebraically closed
residue field. In fact, we prove the following more general result. Let $K$ be
a field such that for every finite extension $L$ of $K$ and for every natural
number $n>0$ the index $[L^*:(L^*)^n]$ is finite and, if $char(K)=p>0$ and $f:
L \to L$ is given by $f(x)=x^p-x$, the index $[L^+:f[L]]$ is also finite. Then
either there is a non-trivial definable valuation on $K$, or every non-trivial
valuation on $K$ has divisible value group and, if $char(K)>0$, it has
algebraically closed residue field. In the zero characteristic case, we get
some partial results of this kind.
  We also notice that minimal fields have the property that every non-trivial
valuation has divisible value group and algebraically closed residue field.


title:
Ground State of the Hydrogen Atom via Dirac Equation in a Minimal Length
  Scenario

abstract:
  In this work we calculate the correction to the ground state energy of the
hydrogen atom due to contributions arising from the presence of a minimal
length. The minimal length scenario is introduced by means of modifying the
Dirac equation through a deformed Heisenberg algebra (kempf algebra). With the
introduction of the Coulomb potential in the new Dirac energy operator, we
calculate the energy shift of the ground state of the hydrogen atom in first
order of the parameter related to the minimal length via perturbation theory.


title: Stable Fixed Points of Card Trick Functions

abstract:
  The 21-card trick is a way of dealing cards in order to predict the card
selected by a volunteer. We give a mathematical explanation of why the
well-known 21-card trick works using a simple linear discrete function. The
function has a stable fixed point which corresponds to the position where the
selected card reaches at the end of the trick. We then generalize the 21(7 x
3)-card trick to a p x q - card trick where p and q are odd integers greater
than or equal to three, determine the fixed point and prove that it is also
stable.


title: Data-Driven Estimation in Equilibrium Using Inverse Optimization

abstract:
  Equilibrium modeling is common in a variety of fields such as game theory and
transportation science. The inputs for these models, however, are often
difficult to estimate, while their outputs, i.e., the equilibria they are meant
to describe, are often directly observable. By combining ideas from inverse
optimization with the theory of variational inequalities, we develop an
efficient, data-driven technique for estimating the parameters of these models
from observed equilibria. We use this technique to estimate the utility
functions of players in a game from their observed actions and to estimate the
congestion function on a road network from traffic count data. A distinguishing
feature of our approach is that it supports both parametric and
\emph{nonparametric} estimation by leveraging ideas from statistical learning
(kernel methods and regularization operators). In computational experiments
involving Nash and Wardrop equilibria in a nonparametric setting, we find that
a) we effectively estimate the unknown demand or congestion function,
respectively, and b) our proposed regularization technique substantially
improves the out-of-sample performance of our estimators.


title: Higher Derivative Gravity and Asymptotic Safety in Diverse Dimensions

abstract:
  We derive the one-loop beta functions for a theory of gravity with generic
action containing up to four derivatives. The calculation is done in arbitrary
dimension and on an arbitrary background. The special cases of three, four,
near four, five and six dimensions are discussed in some detail. We find that
the theories have nontrivial UV fixed points and are asymptotically safe in all
dimensions we study. We also find an indication that Weyl-invariant fixed point
exists in four dimensions. The new massive gravity in three dimensions does not
correspond to any fixed point.


title:
A rapid and highly accurate approximation for the error function of
  complex argument

abstract:
  We present efficient approximation of the error function obtained by Fourier
expansion of the exponential function $\exp [{- {(t - 2 \sigma)^2}/4}]$. The
error analysis reveals that it is highly accurate and can generate numbers that
match up to the last decimal digits with reference values. Due to simple
representation the proposed error function approximation can be utilized in a
rapid algorithm.


title:
Guiding Designs of Self-Organizing Swarms: Interactive and Automated
  Approaches

abstract:
  Self-organization of heterogeneous particle swarms is rich in its dynamics
but hard to design in a traditional top-down manner, especially when many types
of kinetically distinct particles are involved. In this chapter, we discuss how
we have been addressing this problem by (1) utilizing and enhancing interactive
evolutionary design methods and (2) realizing spontaneous evolution of self
organizing swarms within an artificial ecosystem.


title: On the consistency of non-minimally coupled f(R) gravity

abstract:
  Theories with a non-minimal coupling between the space-time curvature and
matter fields introduce an extra force due to the non-conservation of the
matter energy momentum. In the present work the theoretical consistency of such
couplings is studied using a scalar field Lagrangian to model the matter
content. The conditions that the coupling does not introduce ghosts, classical
instabilities or superluminal propagation of perturbations are derived. These
consistency conditions are then employed to rule out or severely restrict the
forms of the non-minimal coupling functions considered in the previous
literature. For example, a power-law coupling is viable only for sublinear
positive power of the curvature scalar.


title:
Pathway drug cocktail: targeting Ras signaling based on structural
  pathways

abstract:
  Tumors bearing Ras mutations are notoriously difficult to treat. Drug
combinations targeting the Ras protein or its pathway have also not met with
success. Pathway drug cocktails, which are combinations aiming at parallel
pathways, appear more promising; however, to be usefully exploited, a
repertoire of classified pathway combinations is desirable. This challenge
would be facilitated by the availability of the structural network of signaling
pathways. When integrated with functional and systems-level clinical data they
can be powerful in advancing novel therapeutic platforms. Based on structural
knowledge, drug cocktails may tear into multiple cellular processes that drive
tumorigenesis, and help in deciphering the interrelationship between Ras
mutations and the rewired Ras network. The pathway drug cocktail paradigm can
be applied to other signaling protein targets.


title:
A new characterization of the CR shpere and the sharp eigenvalue
  estimate for the Kohn Laplacian

abstract:
  Motivated by a sharp eigenvalue estimate for the Kohn Laplacian, we prove a
theorem that characterizes the CR sphere in terms of the existence of a
non-trivial complex-valued function satisfying a certain overdetermined system.


title: On the isoperimetric constant of symmetric spaces of noncompact type

abstract:
  We prove that the isoperimetric constant is positive for all symmetric spaces
of noncompact type and compute it explicitly.


title: On Some Recent MAX SAT Approximation Algorithms

abstract:
  Recently a number of randomized 3/4-approximation algorithms for MAX SAT have
been proposed that all work in the same way: given a fixed ordering of the
variables, the algorithm makes a random assignment to each variable in
sequence, in which the probability of assigning each variable true or false
depends on the current set of satisfied (or unsatisfied) clauses. To our
knowledge, the first such algorithm was proposed by Poloczek and Schnitger; Van
Zuylen subsequently gave an algorithm that set the probabilities differently
and had a simpler analysis. She also set up a framework for deriving such
algorithms. Buchbinder, Feldman, Naor, and Schwartz, as a special case of their
work on maximizing submodular functions, also give a randomized
3/4-approximation algorithm for MAX SAT with the same structure as these
previous algorithms. In this note we give a gloss on the Buchbinder et al.
algorithm that makes it even simpler, and show that in fact it is equivalent to
the previous algorithm of Van Zuylen. We also show how it extends to a
deterministic LP rounding algorithm; such an algorithm was also given by Van
Zuylen.


title: Gauge theory of Lorentz group on the lattice

abstract:
  The model with the fermions coupled in the non - minimal way to the gauge
theory of Lorentz group is considered. The lattice regularization is suggested.
It is argued that this model may exist in the phase with broken chiral symmetry
and without confinement. We speculate about the possibility that this
construction may serve as an origin of the dynamical electroweak symmetry
breaking.


title: Fatou Components with Punctured Limit Sets

abstract:
  We study invariant Fatou components for holomorphic endomorphisms in
$\mathbb{P}^2$. In the recurrent case these components were classified by
Sibony and the second author in 1995. In 2008 Ueda completed this
classification by proving that it is not possible for the limit set to be a
punctured disk. Recently Lyubich and the third author classified non-recurrent
invariant Fatou components, under the additional hypothesis that the limit set
is unique. Again all possibilities in this classification were known to occur,
except for the punctured disk. Here we show that the punctured disk can indeed
occur as the limit set of a non-recurrent Fatou component. We provide many
additional examples of holomorphic and polynomial endomorphisms of
$\mathbb{C}^2$ with non-recurrent Fatou components on which the orbits converge
to the regular part of arbitrary analytic sets.


title: Bogomolov multipliers for unitriangular groups

abstract:
  The Bogomolov multiplier $B_0(G)$ of a finite group $G$ is defined as the
subgroup of the Schur multiplier consisting of the cohomology classes vanishing
after restriction to all abelian subgroups of $G$. In this paper we give a
positive answer to an open problem posed by Kang and Kunyavski\u{i} in
\cite{KK}. Namely, we prove that if $G$ is either a unitriangular group over
$\f$, a quotient of its lower central series, a subgroup of its lower central
series, or a central product of two unitriangular groups, then $B_0(G)=0$.


title:
Angular analysis and branching fraction measurement of the decay B0 to
  K*0 mu+ mu-

abstract:
  The angular distributions and the differential branching fraction of the
decay B0 to K*(892)0 mu+ mu- are studied using a data sample corresponding to
an integrated luminosity of 5.2 inverse femtobarns collected with the CMS
detector at the LHC in pp collisions at sqrt(s) = 7 TeV. From more than 400
signal decays, the forward-backward asymmetry of the muons, the K*(892)0
longitudinal polarization fraction, and the differential branching fraction are
determined as a function of the square of the dimuon invariant mass. The
measurements are in good agreement with standard model predictions.


title:
Characterization of quantum correlations with local dimension
  constraints and its device-independent applications

abstract:
  The future progress of semi-device independent quantum information science
depends crucially on our ability to bound the strength of the nonlocal
correlations achievable with finite dimensional quantum resources. In this
work, we characterize quantum nonlocality under local dimension constraints via
a complete hierarchy of semidefinite programming relaxations. In the bipartite
case, we find that the first level of the hierarchy returns non-trivial bounds
in all cases considered, allowing to study nonlocality scenarios with four
measurement settings on one side and twelve (12) on the other in a normal
desktop. In the tripartite case, we apply the hierarchy to derive a Bell-type
inequality that can only be violated when each of the three parties has local
dimension greater than two, hence certifying three-dimensional tripartite
entanglement in a device independent way. Finally, we show how the new method
can be trivially modified to detect non-separable measurements in two-qubit
scenarios.


title:
Phonon-Spectrum Narrowing Induced by Ultrafast Charge Fluctuation in an
  Organic Dimer Mott Insulator

abstract:
  We have observed the characteristic temperature dependence of the
intermolecular phonon spectrum in the organic dimer Mott insulator
kappa-(ET)2Cu2(CN)3 exhibiting a dielectric anomaly at 30 K. The anomalous
spectral narrowing of the 55 cm-1 phonon peak at 30 K was analyzed in terms of
motional narrowing within the framework of a stationary Gaussian process, i.
e., the phonon frequency is modulated by the ultrafast charge fluctuation. The
spectral narrowing occurs because the time constant of the correlation time
tau_c and the amplitude of the frequency modulation delta satisfy the relation
tau_c<delta at 30 K. At temperatures below 30 K, the motional narrowing is
disturbed by the increasing of tau_c, near the charge-glass or the short-range
order at 6 K. On the other hand, for temperatures above 30 K, the motional
narrowing is disturbed by the increase of delta with increasing temperature.


title:
The VLT-FLAMES Tarantula Survey - XI. A census of the hot luminous stars
  and their feedback in 30 Doradus

abstract:
  We compile the first comprehensive census of hot luminous stars in the 30
Doradus (30 Dor) star forming region of the LMC. The census extends to a radius
of 10arcmin (150pc) from the central cluster, R136. Stars were selected
photometrically and combined with the latest spectral types. 1145 candidate hot
luminous stars were identified of which >700 were considered genuine early type
stars that contribute to feedback. We assess the spectroscopic completeness to
be 85% in outer regions (>5pc) but fall to 35% in the vicinity of R136, giving
a total of 500 hot luminous stars with spectroscopy. Stellar calibrations and
models were used to obtain their physical parameters before integrated values
were compared to global observations and the population synthesis code,
Starburst99. The 31 W-R and Of/WN stars made large contributions to the total
ionising and wind luminosities of ~40% and ~50%, respectively. Stars with
Minit>100Msun also showed high contributions to the global feedback, ~25% in
both cases. Such massive stars are not accounted for by the current Starburst99
code, which underestimated the ionising and wind luminosities of R136 by
factors of ~2 and ~9, respectively. The census inferred a SFR of
0.073+/-0.04Msun/yr for 30 Dor, typically higher than results from popular SFR
calibrations. However, it remained consistent with a far-UV luminosity tracer
and a combined Halpha and mid-infrared tracer, but only after correcting for
Halpha extinction. The global ionising output exceeded measurements from the
associated gas and dust, suggesting ~6(+55/-6)% of ionising photons escape the
region. When studying very luminous star forming regions, it is therefore
essential to include the most massive stars to ensure a reliable energy budget.
If 30 Dor is typical of other large star forming regions, estimates of the SFR
will be underpredicted if this escape fraction is not accounted for.(abridged)


title: Friedmann-Robertson-Walker like cosmologies with spherical symmetry

abstract:
  We reconsider the cosmological model discussed by Sung-Won Kim [Phys. Rev D
53, 6889 (1996)] in the context of Friedmann-Robertson-Walker cosmologies with
a traversable wormhole, where it is assumed that the matter content is divided
into two parts: the cosmic part that depends on time only and the wormhole part
that depends on space only. The cosmic part obeys the barotropic equation of
state $p_c=\gamma \rho_c$. The complete analysis requires further care and
reveals more interesting results than what was previously shown by the author.
They can be readily applied to the evolution of a large class of cosmological
models which are more general than FRW models.


title: Theoretical expectation of large Seebeck effect in PtAs$_2$ and PtP$_2$

abstract:
  Motivated by a recent observation of good thermoelectric properties in %a
%pyrite material PtSb$_2$, we theoretically study related pyrites %materials in
an attempt to %find a %better thermoelectric material. %Our aim is to seek for
a material which overcomes the suppression of the Seebeck coefficient at high
temperatures.% in PtSb$_2$. We find that PtAs$_2$ and PtP$_2$ are good
candidates, where a larger band gap than in PtSb$_2$ combined with the overall
flatness of the band top gives rise to a monotonically increasing Seebeck
coefficient up to high temperatures. This expectation has been confirmed quite
recently for hole doped PtAs$_2$, where a very large power factor of $\sim$
65$\mu$W/cmK$^2$ at T=440 K is observed.


title:
The Relationship Between EUV Nonthermal Line Broadening and High-energy
  Particle During Solar Flare

abstract:
  We have studied the relationship between the location of EUV nonthermal
broadening and high-energy particles during the large flares by using EUV
imaging spectrometer onboard {\it Hinode}, Nobeyama Radio Polarimeter, Nobeyama
Radioheliograph, and Atmospheric Imaging Assembly onboard {\it Solar Dynamic
Observatory}. We have analyzed the five large flare events which contain
thermal rich, intermediate, and thermal poor flares classified by the
definition discussed in the paper. We found that, in the case of thermal rich
flares, the nonthermal broadening of \ion{Fe}{24} occurred at the top of the
flaring loop at the beginning of the flares. The source of the 17 GHz microwave
is located at the footpoint of the flare loop. On the other hand, in the case
of intermediate/thermal poor flares, the nonthermal broadening of \ion{Fe}{24}
occurred at the footpoint of the flare loop at the beginning of the flares. The
source of the 17 GHz microwave is located at the top of the flaring loop. We
discussed the difference between thermal rich and intermediate/thermal poor
flare based on the spatial information of nonthermal broadening, which may give
a clue for the presence of turbulence playing an important role in the pitch
angle scattering of the high-energy electron.


title:
Tuning Parameter Selection in Regularized Estimations of Large
  Covariance Matrices

abstract:
  Recently many regularized estimators of large covariance matrices have been
proposed, and the tuning parameters in these estimators are usually selected
via cross-validation. However, there is no guideline on the number of folds for
conducting cross-validation and there is no comparison between cross-validation
and the methods based on bootstrap. Through extensive simulations, we suggest
10-fold cross-validation (nine-tenths for training and one-tenth for
validation) be appropriate when the estimation accuracy is measured in the
Frobenius norm, while 2-fold cross-validation (half for training and half for
validation) or reverse 3-fold cross-validation (one-third for training and
two-thirds for validation) be appropriate in the operator norm. We also suggest
the "optimal" cross-validation be more appropriate than the methods based on
bootstrap for both types of norm.


title:
Eigenvalue of Fricke involution on newforms of level 4 and of trivial
  character

abstract:
  In this note, we consider the newforms of integral weight, level 4 and of
trivial character, and prove that all of them are actually level 1 forms of
some non-Dirichlet character. As a byproduct, we can prove that all of them are
eigenfunctions of the Fricke involution with eigenvalue -1.


title:
The Interpolating Airy Kernels for the beta=1 and beta=4 Elliptic
  Ginibre Ensembles

abstract:
  We consider two families of non-Hermitian Gaussian random matrices, namely
the elliptical Ginibre ensembles of asymmetric N-by-N matrices with Dyson index
beta=1 (real elements) and with beta=4 (quaternion-real elements). Both
ensembles have already been solved for finite N using the method of
skew-orthogonal polynomials, given for these particular ensembles in terms of
Hermite polynomials in the complex plane. In this paper we investigate the
microscopic weakly non-Hermitian large-N limit of each ensemble in the vicinity
of the largest or smallest real eigenvalue. Specifically, we derive the
limiting matrix-kernels for each case, from which all the eigenvalue
correlation functions can be determined. We call these new kernels the
"interpolating" Airy kernels, since we can recover -- as opposing limiting
cases -- not only the well-known Airy kernels for the Hermitian ensembles, but
also the complementary error function and Poisson kernels for the maximally
non-Hermitian ensembles at the edge of the spectrum. Together with the known
interpolating Airy kernel for beta=2, which we rederive here as well, this
completes the analysis of all three elliptical Ginibre ensembles in the
microscopic scaling limit at the spectral edge.


title: Colliding clusters and dark matter self-interactions

abstract:
  When a dark matter halo moves through a background of dark matter particles,
self-interactions can lead to both deceleration and evaporation of the halo and
thus shift its centroid relative to the collisionless stars and galaxies. We
study the magnitude and time evolution of this shift for two classes of dark
matter self-interactions, viz. frequent self-interactions with small momentum
transfer (e.g. due to long-range interactions) and rare self-interactions with
large momentum transfer (e.g. contact interactions), and find important
differences between the two cases. We find that neither effect can be strong
enough to completely separate the dark matter halo from the galaxies, if we
impose conservative bounds on the self-interaction cross-section. The majority
of both populations remain bound to the same gravitational potential and the
peaks of their distributions are therefore always coincident. Consequently any
apparent separation is mainly due to particles which are leaving the
gravitational potential, so will be largest shortly after the collision but not
observable in evolved systems. Nevertheless the fraction of collisions with
large momentum transfer is an important characteristic of self-interactions,
which can potentially be extracted from observational data and provide an
important clue as to the nature of dark matter.


title: 3D Printing for Math Professors and Their Students

abstract:
  In this primer, we will describe a number of projects that can be completed
with a 3D printer, particularly by mathematics professors and their students.
For many of the projects, we will utilize Mathematica to design objects that
mathematicians may be interested in printing. Included in the projects that are
described is a method to acquire data from an XBox Kinect.


title: Magnetic field generation and amplification in an expanding plasma

abstract:
  Particle-in-cell simulations are used to investigate the formation of
magnetic fields, B, in plasmas with perpendicular electron density and
temperature gradients. For system sizes, L, comparable to the ion skin depth,
d_i, it is shown that B ~ d_i/L, consistent with the Biermann battery effect.
However, for large L/d_i, it is found that the Weibel instability (due to
electron temperature anisotropy) supersedes the Biermann battery as the main
producer of B. The Weibel-produced fields saturate at a finite amplitude
(plasma \beta \approx 100), independent of L. The magnetic energy spectra below
the electron Larmor radius scale is well fitted by power law with slope -16/3,
as predicted in Schekochihin et al., Astrophys. J. Suppl. Ser 182, 310 (2009).


title:
Time-dependent polarization states of high power, ultrashort laser
  pulses during atmospheric propagation

abstract:
  We investigate, through simulation, the evolution of polarization states
during atmospheric propagation of high power, ultrashort laser pulses. A
delayed rotational response model handling arbitrary, transverse polarization
couples both the amplitude and phase of the polarization states. We find that,
while circularly and linearly polarized pulses maintain their polarization,
elliptically polarized pulses become depolarized due to energy equilibration
between left and right circularly polarized states. The depolarization can be
detrimental to remote radiation generation schemes and obscures time-integrated
polarization measurements.


title:
Chains(R) does not admit a geometrically meaningful properadic homotopy
  Frobenius algebra structure

abstract:
  The embedding Chains(R) into Cochains(R) as the compactly supported cochains
might lead one to expect Chains(R) to carry a nonunital commutative Frobenius
algebra structure, up to a degree shift and some homotopic weakening of the
axioms. We prove that under reasonable "locality" conditions, a cofibrant
resolution of the dioperad controlling nonunital shifted-Frobenius algebras
does act on Chains(R), and in a homotopically-unique way. But we prove that
this action does not extend to a homotopy Frobenius action at the level of
properads or props. This gives an example of a geometrically meaningful
algebraic structure on homology that does not lift in a geometrically
meaningful way to the chain level.


title:
Redox reactions with empirical potentials: Atomistic battery discharge
  simulations

abstract:
  Batteries are pivotal components in overcoming some of today's greatest
technological challenges. Yet to date there is no self-consistent atomistic
description of a complete battery. We take first steps toward modeling of a
battery as a whole microscopically. Our focus lies on phenomena occurring at
the electrode-electrolyte interface which are not easily studied with other
methods. We use the redox split-charge equilibration (redoxSQE) method that
assigns a discrete ionization state to each atom. Along with exchanging partial
charges across bonds, atoms can swap integer charges. With redoxSQE we study
the discharge behavior of a nano-battery, and demonstrate that this reproduces
the generic properties of a macroscopic battery qualitatively. Examples are the
dependence of the battery's capacity on temperature and discharge rate, as well
as performance degradation upon recharge.


title:
Experimental determination of conduction channels in atomic scale
  conductors based on shot noise measurements

abstract:
  We present an experimental procedure for obtaining the conduction channels of
low-dimensional conductors based on shot noise measurements. The transmission
coefficient for each channel is determined numerically from the measured
conductance and Fano factor. The channel analysis is demonstrated for atomic
contacts of Ag, Au, Al and Pt, showing their channel evolution as a function of
conductance and mechanical elongation. This approach can be readily applied to
map the conduction channels in a wide range of nanoscale conductors under
different conditions.


title:
Magnetic Phase Diagram of a Five-Orbital Hubbard Model in the Real-Space
  Hartree Fock Approximation Varying the Electronic Density

abstract:
  Using the real-space Hartree Fock approximation, the magnetic phase diagram
of a five-orbital Hubbard model for the iron-based superconductors is studied
varying the electronic density $n$ in the range from 5 to 7 electrons per
transition metal atom. The Hubbard interaction $U$ is also varied, at a fixed
Hund coupling $J/U=0.25$. Several qualitative trends and a variety of competing
magnetic states are observed. At $n$=5, a robust G-type antiferromagnetic
insulator is found, in agreement with experimental results for BaMn$_2$As$_2$.
As $n$ increases away from 5, magnetic states with an increasing number of
nearest-neighbors ferromagnetic links become energetically stable. This
includes the well-known C-type antiferromagnetic state at $n$=6, the E-phase
known to exist in FeTe, and also a variety of novel states not found yet
experimentally, some of them involving blocks of ferromagnetically oriented
spins. Regions of phase separation, as in Mn-oxides, have also been detected.
Comparison with previous theoretical investigations indicate that these
qualitative trends may be generic characteristics of phase diagrams of
multiorbital Hubbard models.


title:
Some sharp bounds on the distance signless Laplacian spectral radius of
  graphs

abstract:
  M. Aouchiche and P. Hansen proposed the distance Laplacian and the distance
signless Laplacian of a connected graph [Two Laplacians for the distance matrix
of a graph, LAA 439 (2013) 21{33]. In this paper, we obtain three theorems on
the sharp upper bounds of the spectral radius of a nonnegative matrix, then
apply these theorems to signless Laplacian matrices and the distance signless
Laplacian matrices to obtain some sharp bounds on the spectral radius,
respectively. We also proposed a known result about the sharp bound of the
signless Laplacian spectral radius has a defect.


title: Spintronics and Pseudospintronics in Graphene and Topological Insulators

abstract:
  The two-dimensional electron systems in graphene and in topological
insulators are described by massless Dirac equations. Although the two systems
have similar Hamiltonians, they are polar opposites in terms of spin-orbit
coupling strength. We briefly review the status of efforts to achieve long spin
relaxation times in graphene with its weak spin-orbit coupling, and to achieve
large current-induced spin polarizations in topological-insulator surface
states that have strong spin-orbit coupling. We also comment on differences
between the magnetic responses and dilute-moment coupling properties of the two
systems, and on the pseudospin analog of giant magnetoresistance in bilayer
graphene.


title: On the Moore-Penrose inverse in $C^*$-algebras

abstract:
  In this article, two results regarding the Moore-Penrose inverse in the frame
of $C^*$-algebras are considered. In first place, a characterization of the
so-called reverse order law is given, which provides a solution of a problem
posed by M. Mbekhta. On the other hand, Moore-Penrose hermitian elements, that
is $C^*$-algebra elements which coincide with their Moore-Penrose inverse, are
introduced and studied. In fact,these elements will be fully characterized both
in the Hilbert space and in the $C^*$-algebra setting. Furthermore, it will be
proved that an element is normal and Moore-Penrose hermitian if and only if it
is a hermitian partial isometry.


title: Centralizers in Ore extensions of polynomial rings

abstract:
  In this paper we consider centralizers of single elements in Ore extensions
of the ring of polynomials in one variable over a field. We show that they are
commutative and finitely generated as an algebra. We also show that for certain
classes of elements their centralizer is singly generated as an algebra.


title: Zero measure Cantor spectra for continuum one-dimensional quasicrystals

abstract:
  We study Schr\"odinger operators on $\R$ with measures as potentials.
  Choosing a suitable subset of measures we can work with a dynamical system
consisting of measures. We then relate properties of this dynamical system with
spectral properties of the associated operators.
  The constant spectrum in the strictly ergodic case coincides with the union
of the zeros of the Lyapunov exponent and the set of non-uniformities of the
transfer matrices.
  This result enables us to prove Cantor spectra of zero Lebesgue measure for a
large class of operator families, including many operator families generated by
aperiodic subshifts.


title:
Estimating or Propagating Gradients Through Stochastic Neurons for
  Conditional Computation

abstract:
  Stochastic neurons and hard non-linearities can be useful for a number of
reasons in deep learning models, but in many cases they pose a challenging
problem: how to estimate the gradient of a loss function with respect to the
input of such stochastic or non-smooth neurons? I.e., can we "back-propagate"
through these stochastic neurons? We examine this question, existing
approaches, and compare four families of solutions, applicable in different
settings. One of them is the minimum variance unbiased gradient estimator for
stochatic binary neurons (a special case of the REINFORCE algorithm). A second
approach, introduced here, decomposes the operation of a binary stochastic
neuron into a stochastic binary part and a smooth differentiable part, which
approximates the expected effect of the pure stochatic binary neuron to first
order. A third approach involves the injection of additive or multiplicative
noise in a computational graph that is otherwise differentiable. A fourth
approach heuristically copies the gradient with respect to the stochastic
output directly as an estimator of the gradient with respect to the sigmoid
argument (we call this the straight-through estimator). To explore a context
where these estimators are useful, we consider a small-scale version of {\em
conditional computation}, where sparse stochastic units form a distributed
representation of gaters that can turn off in combinatorially many ways large
chunks of the computation performed in the rest of the neural network. In this
case, it is important that the gating units produce an actual 0 most of the
time. The resulting sparsity can be potentially be exploited to greatly reduce
the computational cost of large deep networks for which conditional computation
would be useful.


title:
Detection of the microwave spin pumping using the inverse spin Hall
  effect

abstract:
  We report electrical detection of the dynamical part of the spin pumping
current emitted during ferromagnetic resonance (FMR) using the inverse Spin
Hall Effect (ISHE). The experiment is performed on a YIG$|$Pt bilayer. The
choice of YIG, a magnetic insulator, ensures that no charge current flows
between the two layers and only pure spin current produced by the magnetization
dynamics are transferred into the adjacent strong spin-orbit Pt layer via spin
pumping. To avoid measuring the parasitic eddy currents induced at the
frequency of the microwave source, a resonance at half the frequency is induced
using parametric excitation in the parallel geometry. Triggering this nonlinear
effect allows to directly detect on a spectrum analyzer the microwave component
of the ISHE voltage. Signals as large as 30 $\mu$V are measured for precession
angles of a couple of degrees. This direct detection provides a novel efficient
means to study magnetization dynamics on a very wide frequency range with great
sensitivity.


title: Evolution of the L1 halo family in the radial solar sail CRTBP

abstract:
  We present a detailed investigation of the dramatic changes that occur in the
$\mathcal{L}_1$ halo family when radiation pressure is introduced into the
Sun-Earth circular restricted three-body problem (CRTBP). This
photo-gravitational CRTBP can be used to model the motion of a solar sail
orientated perpendicular to the Sun-line. The problem is then parameterized by
the sail lightness number, the ratio of solar radiation pressure acceleration
to solar gravitational acceleration. Using boundary-value problem numerical
continuation methods and the AUTO software package (Doedel et al. 1991) the
families can be fully mapped out as the parameter $\beta$ is increased.
Interestingly, the emergence of a branch point in the retrograde satellite
family around the Earth at $\beta\approx0.0387$ acts to split the halo family
into two new families. As radiation pressure is further increased one of these
new families subsequently merges with another non-planar family at
$\beta\approx0.289$, resulting in a third new family. The linear stability of
the families changes rapidly at low values of $\beta$, with several small
regions of neutral stability appearing and disappearing. By using existing
methods within AUTO to continue branch points and period-doubling bifurcations,
and deriving a new boundary-value problem formulation to continue the folds and
Krein collisions, we track bifurcations and changes in the linear stability of
the families in the parameter $\beta$ and provide a comprehensive overview of
the halo family in the presence of radiation pressure. The results demonstrate
that even at small values of $\beta$ there is significant difference to the
classical CRTBP, providing opportunity for novel solar sail trajectories.
Further, we also find that the branch points between families in the solar sail
CRTBP provide a simple means of generating certain families in the classical
case.


title: A note on discrete R symmetries in Z6-II orbifolds with Wilson lines

abstract:
  We re-derive the R symmetries for the Z6-II orbifold with non-trivial Wilson
lines and find expressions for the R charges which differ from those in the
literature.


title:
Reference frame independent quantum key distribution server with telecom
  tether for on-chip client

abstract:
  We demonstrate a client-server quantum key distribution (QKD) scheme, with
large resources such as laser and detectors situated at the server-side, which
is accessible via telecom-fibre, to a client requiring only an on-chip
polarisation rotator, that may be integrated into a handheld device. The
detrimental effects of unstable fibre birefringence are overcome by employing
the reference frame independent QKD protocol for polarisation qubits in
polarisation maintaining fibre, where standard QKD protocols fail, as we show
for comparison. This opens the way for quantum enhanced secure communications
between companies and members of the general public equipped with handheld
mobile devices, via telecom-fibre tethering.


title:
Multi-dimensional radiative transfer to analyze Hanle effect in Ca {\sc
  ii} K line at 3933 \AA\,

abstract:
  Radiative transfer (RT) studies of the linearly polarized spectrum of the Sun
(the second solar spectrum) have generally focused on the line formation, with
an aim to understand the vertical structure of the solar atmosphere using
one-dimensional (1D) model atmospheres. Modeling spatial structuring in the
observations of the linearly polarized line profiles requires the solution of
multi-dimensional (multi-D) polarized RT equation and a model solar atmosphere
obtained by magneto-hydrodynamical (MHD) simulations of the solar atmosphere.
Our aim in this paper is to analyze the chromospheric resonance line Ca {\sc
ii} K at 3933 \AA\ using multi-D polarized RT with Hanle effect and partial
frequency redistribution in line scattering. We use an atmosphere which is
constructed by a two-dimensional snapshot of the three-dimensional MHD
simulations of the solar photosphere, combined with columns of an 1D atmosphere
in the chromosphere. This paper represents the first application of polarized
multi-D RT to explore the chromospheric lines using multi-D MHD atmospheres,
with PRD as the line scattering mechanism. We find that the horizontal
inhomogeneities caused by MHD in the lower layers of the atmosphere are
responsible for strong spatial inhomogeneities in the wings of the linear
polarization profiles, while the use of horizontally homogeneous chromosphere
(FALC) produces spatially homogeneous linear polarization in the line core.


title: Identification of hybrid node and link communities in complex networks

abstract:
  Identification of communities in complex networks has become an effective
means to analysis of complex systems. It has broad applications in diverse
areas such as social science, engineering, biology and medicine. Finding
communities of nodes and finding communities of links are two popular schemes
for network structure analysis. These schemes, however, have inherent drawbacks
and are often inadequate to properly capture complex organizational structures
in real networks. We introduce a new scheme and effective approach for
identifying complex network structures using a mixture of node and link
communities, called hybrid node-link communities. A central piece of our
approach is a probabilistic model that accommodates node, link and hybrid
node-link communities. Our extensive experiments on various real-world
networks, including a large protein-protein interaction network and a large
semantic association network of commonly used words, illustrated that the
scheme for hybrid communities is superior in revealing network characteristics.
Moreover, the new approach outperformed the existing methods for finding node
or link communities separately.


title:
Interpretation of $Z_c(4025)$ as the Hidden Charm Tetraquark States via
  QCD Sum Rules

abstract:
  By using QCD Sum Rules, we found that the charged hidden charm tetraquark $[c
u][\bar{c} \bar{d}]$ states with $ J^P = 1^-$ and $ 2^+$, which are possible
quantum numbers of the newly observed charmonium-like resonance $Z_c(4025)$,
have masses of $m_{1^-}^c = (4.54 \pm 0.20) \, \text{GeV}$ and $m_{2^+}^c =
(4.04 \pm 0.19) \, \text{GeV}$. The contributions up to dimension eight in the
Operator Product Expansion (OPE) were taken into account in the calculation.
The tetraquark mass of $J^{P} = 2^{+}$ state was consistent with the
experimental data of $Z_c(4025)$, suggesting the $Z_c(4025)$ state possessing
the quantum number of $J^P = 2^+$. Extending to the b-quark sector, the
corresponding tetraquark masses $m_{1^-}^b = (10.97 \pm 0.25) \, \text{GeV}$
and $m_{2^+}^b = (10.35 \pm 0.25) \, \text{GeV}$ were obtained, which are
testable in future B-factories.


title:
Strong magnetic fields and large rotation measures in protogalaxies by
  supernova seeding

abstract:
  We present a model for the seeding and evolution of magnetic fields in
protogalaxies. Supernova (SN) explosions during the assembly of a protogalaxy
provide magnetic seed fields, which are subsequently amplified by compression,
shear flows and random motions. We implement the model into the MHD version of
the cosmological N-body / SPH simulation code GADGET and we couple the magnetic
seeding directly to the underlying multi-phase description of star formation.
We perform simulations of Milky Way-like galactic halo formation using a
standard LCDM cosmology and analyse the strength and distribution of the
subsequent evolving magnetic field. A dipole-shape divergence-free magnetic
field is injected at a rate of 10^{-9}G / Gyr within starforming regions, given
typical dimensions and magnetic field strengths in canonical SN remnants.
Subsequently, the magnetic field strength increases exponentially on timescales
of a few ten million years. At redshift z=0, the entire galactic halo is
magnetized and the field amplitude is of the order of a few $\mu$G in the
center of the halo, and 10^{-9} G at the virial radius. Additionally, we
analyse the intrinsic rotation measure (RM) of the forming galactic halo over
redshift. The mean halo intrinsic RM peaks between redshifts z=4 and z=2 and
reaches absolute values around 1000 rad m^{-2}. While the halo virializes
towards redshift z=0, the intrinsic RM values decline to a mean value below 10
rad m^{-2}. At high redshifts, the distribution of individual starforming, and
thus magnetized regions is widespread. In our model for the evolution of
galactic magnetic fields, the seed magnetic field amplitude and distribution is
no longer a free parameter, but determined self-consistently by the star
formation process occuring during the formation of cosmic structures.


title:
Experimental realization of transverse mode conversion using optically
  induced transient long-period gratings

abstract:
  We present the experimental realization of transverse mode conversion in an
optical fiber via an optically induced long-period grating. The transient
gratings are generated by femtosecond laser pulses, exploiting the Kerr effect
to translate intensity patterns emerging from multimode interference into a
spatial refractive index modulation. Since these modulations exist only while
the pump beam is present, they can be used for optical switching of transverse
modes. As only a localized part of the grating was written at a time and the
probe beam was co-propagating with the pump beam the required pulse energies
could be reduced to 120\,nJ which is about a factor of 600 lower than in
previous quasi-continuous-wave experiments. Accompanying numerical simulations
allow a better understanding of the involved effects and show excellent
agreement to the experimental results.


title: Remarks on Finsler Geometry and Lorentz Violation

abstract:
  The physics of classical particles in a Lorentz-breaking spacetime has
numerous features resembling the properties of Finsler geometry. In particular,
the Lagrange function plays a role similar to that of a Finsler structure
function. A summary is presented of recent results, including new calculable
Finsler structures based on Lagrange functions appearing in the
Lorentz-violation framework known as the Standard-Model Extension.


title:
Polarized Line Formation in Multi-dimensional Media. V. Effects of
  Angle-Dependent Partial Frequency Redistribution

abstract:
  The solution of polarized radiative transfer equation with angle-dependent
(AD) partial frequency redistribution (PRD) is a challenging problem. Modeling
the observed, linearly polarized strong resonance lines in the solar spectrum
often requires the solution of the AD line transfer problems in one-dimensional
(1D) or multi-dimensional (multi-D) geometries. The purpose of this paper is to
develop an understanding of the relative importance of the AD PRD effects and
the multi-D transfer effects and particularly their combined influence on the
line polarization. This would help in a quantitative analysis of the second
solar spectrum (the linearly polarized spectrum of the Sun). We consider both
non-magnetic and magnetic media. In this paper we reduce the Stokes vector
transfer equation to a simpler form using a Fourier decomposition technique for
multi-D media. A fast numerical method is also devised to solve the concerned
multi-D transfer problem. The numerical results are presented for a
two-dimensional medium with a moderate optical thickness (effectively thin),
and are computed for a collisionless frequency redistribution. We show that the
AD PRD effects are significant, and can not be ignored in a quantitative fine
analysis of the line polarization. These effects are accentuated by the finite
dimensionality of the medium (multi-D transfer). The presence of magnetic
fields (Hanle effect) modifies the impact of these two effects to a
considerable extent.


title: Baxter's Relations and Spectra of Quantum Integrable Models

abstract:
  Generalized Baxter's relations on the transfer-matrices (also known as
Baxter's TQ relations) are constructed and proved for an arbitrary untwisted
quantum affine algebra. Moreover, we interpret them as relations in the
Grothendieck ring of the category O introduced by Jimbo and the second author
in arXiv:1104.1891 involving infinite-dimensional representations constructed
in arXiv:1104.1891, which we call here "prefundamental". We define the
transfer-matrices associated to the prefundamental representations and prove
that their eigenvalues on any finite-dimensional representation are polynomials
up to a universal factor. These polynomials are the analogues of the celebrated
Baxter polynomials. Combining these two results, we express the spectra of the
transfer-matrices in the general quantum integrable systems associated to an
arbitrary untwisted quantum affine algebra in terms of our generalized Baxter
polynomials. This proves a conjecture of Reshetikhin and the first author
formulated in 1998 (arXiv:math/9810055). We also obtain generalized Bethe
Ansatz equations for all untwisted quantum affine algebras.

categories: math.QA cond-mat.stat-mech hep-th math-ph math.MP math.RT


title: The Electromagnetic Calorimeter for the T2K Near Detector ND280

abstract:
  The T2K experiment studies oscillations of an off-axis muon neutrino beam
between the J-PARC accelerator complex and the Super-Kamiokande detector.
Special emphasis is placed on measuring the mixing angle theta_13 by observing
electron neutrino appearance via the sub-dominant muon neutrino to electron
neutrino oscillation, and searching for CP violation in the lepton sector. The
experiment includes a sophisticated, off-axis, near detector, the ND280,
situated 280 m downstream of the neutrino production target in order to measure
the properties of the neutrino beam and to understand better neutrino
interactions at the energy scale below a few GeV. The data collected with the
ND280 are used to study charged- and neutral-current neutrino interaction rates
and kinematics prior to oscillation, in order to reduce uncertainties in the
oscillation measurements by the far detector. A key element of the near
detector is the ND280 electromagnetic calorimeter (ECal), consisting of active
scintillator bars sandwiched between lead sheets and read outwith multi-pixel
photon counters (MPPCs). The ECal is vital to the reconstruction of neutral
particles, and the identification of charged particle species. The ECal
surrounds the Pi-0 detector (P0D) and the tracking region of the ND280, and is
enclosed in the former UA1/NOMAD dipole magnet. This paper describes the
design, construction and assembly of the ECal, as well as the materials from
which it is composed. The electronic and data acquisition (DAQ) systems are
discussed, and performance of the ECal modules, as deduced from measurements
with particle beams, cosmic rays, the calibration system, and T2K data, is
described.


title: PMT Triggering and Readout for the MicroBooNE Experiment

abstract:
  This paper presents the proposed PMT readout and triggering system that will
be used in the MicroBooNE LArTPC experiment. The triggering scheme has been
designed to study beam neutrino events as well as fully characterize cosmic
rays. In addition, exploration of important physics applications including
"late" scintillation light in argon and Michel electrons from muon decay will
be possible. Various types of triggers and how they will be implemented in the
combined PMT+TPC readout electronics system will be discussed.


title:
Polarized Line Formation in Multi-dimensional Media. IV. A Fourier
  Decomposition Technique To Formulate The Transfer Equation With
  Angle-Dependent Partial Frequency Redistribution

abstract:
  To explain the linear polarization observed in spatially resolved structures
in the solar atmosphere, the solution of polarized radiative transfer (RT)
equation in multi-dimensional (multi-D) geometries is essential. For strong
resonance lines partial frequency redistribution (PRD) effects also become
important. In a series of papers we have been investigating the nature of
Stokes profiles formed in multi-D media including PRD in line scattering. For
numerical simplicity so far we restricted our attention to the particular case
of PRD functions which are averaged over all the incident and scattered
directions. In this paper we formulate the polarized RT equation in multi-D
media that takes into account Hanle effect with angle-dependent PRD functions.
We generalize here to the multi-D case, the method of Fourier series expansion
of angle-dependent PRD functions originally developed for RT in 1D geometry. We
show that the Stokes source vector $\bm{S}=(S_I,S_Q,S_U)^T$ and the Stokes
vector $\bm{I}=(I,Q,U)^T$ can be expanded in terms of infinite sets of
components ${\tilde{\bm{\mathcal{S}}}}^{(k)}$,
${\tilde{\bm{\mathcal{I}}}}^{(k)}$ respectively, $k\in[0,+\infty)$. We show
that the components ${\tilde{\bm{\mathcal{S}}}}^{(k)}$ become independent of
the azimuthal angle ($\varphi$) of the scattered ray, whereas the components
${\tilde{\bm{\mathcal{I}}}}^{(k)}$ remain dependent on $\varphi$ due to the
nature of RT in multi-D geometry. We also establish that
${\tilde{\bm{\mathcal{S}}}}^{(k)}$ and ${\tilde{\bm{\mathcal{I}}}}^{(k)}$
satisfy a simple transfer equation, which can be solved by any iterative method
like an Approximate Lambda Iteration (ALI) or a Biconjugate-Gradient type
projection method provided we truncate the Fourier series to have a finite
number of terms.


title: U-spin breaking in CP asymmetries in B decays

abstract:
  U-spin symmetry predicts equal CP rate asymmetries with opposite signs in
pairs of $\Delta S=0$ and $\Delta S=1$ $B$ meson decays in which initial and
final states are related by U-spin reflection. Of particular interest are six
decay modes to final states with pairs of charged pions or kaons, including
$B_s \to \pi^+K^-$ and $B_s\to K^+K^-$ for which asymmetries have been reported
recently by the LHCb collaboration. After reviewing the current status of these
predictions, highlighted by the precision of a relation between asymmetries in
$B_s \to \pi^+K^-$ and $B^0\to K^+\pi^-$, we perform a perturbative study of
U-spin breaking corrections, searching for relations for combined asymmetries
which hold to first order. No such relation is found in these six decays, in
two-body decays involving a neutral kaon, and in three-body $B^+$ decays to
charged pions and kaons.


title: Self-Affine Elastic Contacts: Percolation and Leakage

abstract:
  We study fluid flow at the interfaces between elastic solids with randomly
rough, self-affine surfaces. We show by numerical simulation that elastic
deformation lowers the relative contact area at which contact patches percolate
in comparison to traditional approaches to seals. Elastic deformation also
suppresses leakage through contacts even far away from the percolation
threshold. Reliable estimates for leakage can be obtained by combining
Persson's contact mechanics theory with a slightly modified version of
Bruggeman's effective-medium solution of the Reynolds equation.


title: Interacting Ghost Dark Energy Models with Variable $G$ and $\Lambda$

abstract:
  In this paper we consider several phenomenological models of variable
$\Lambda$. Model of a flat Universe with variable $\Lambda$ and $G$ is
accepted. It is well known, that varying $G$ and $\Lambda$ gives rise to
modified field equations and modified conservation laws, which gives rise to
many different manipulations and assumptions in literature. We will consider
two component fluid, which parameters will enter to $\Lambda$. Interaction
between fluids with energy densities $\rho_{1}$ and $\rho_{2}$ assumed as
$Q=3Hb(\rho_{1}+\rho_{2})$. We have numerical analyze of important cosmological
parameters like EoS parameter of the composed fluid and deceleration parameter
$q$ of the model.


title: Equational Noetherian Algebras and Chain Conditions

abstract:
  In this article, we describe the relation between the properties of being
equational noetherian and ascending chain condition on ideals of an arbitrary
algebra. We also give a formulation of Hilbert's basis theorem for varieties of
algebras and obtain a criterion to investigate it for a given variety.


title: A combinatorial approach to rational exponential groups

abstract:
  We give a suitable definition of the concept of rational complex and prove
that every rational exponential group is the fundamental group of some such a
complex. In this framework, we prove that the variety of rational exponential
groups is a Schreier variety.


title: Electrodynamic Effects of Inflationary Gravitons

abstract:
  We calculate the one-loop corrections from inflationary gravitons to the
electromagnetic fields of a point charge and a point magnetic dipole on a
locally de Sitter space background. Results are obtained both for an observer
at rest in co-moving coordinates, whose physical distance from the sources
increases with the expanding universe, and for an observer at rest in static
coordinates, whose physical distance from the sources is constant. The fields
of both sources show the de Sitter analogs of the fractional $G/r^2$
corrections which occur in flat space, but there are also some fractional $G
H^2$ corrections due to the scattering of virtual photons from the vast
ensemble of infrared gravitons produced by inflation. The co-moving observer
perceives the magnitude of the point charge to increase linearly with co-moving
time and logarithmically with the co-moving position, however, the magnetic
dipole shows only a negative logarithmic spatial variation. The static observer
perceives no secular change of the point charge but he does report a secular
enhancement of the magnetic dipole moment.


title:
Congruences for Ramanujan's f and {\omega} functions via generalized
  Borcherds products

abstract:
  Bruinier and Ono recently developed the theory of generalized Borcherds
products, which uses coefficients of certain Maass forms as exponents in
infinite product expansions of meromorphic modular forms. Using this, one can
use classical results on congruences of modular forms to obtain congruences for
Maass forms. In this note we work out the example of Ramanujan's mock theta
functions f and {\omega} in detail.


title: A Stronger Bell Argument for (Some Kind of) Parameter Dependence

abstract:
  It is widely accepted that the violation of Bell inequalities excludes local
theories of the quantum realm. This paper presents a new derivation of the
inequalities from non-trivial non-local theories and formulates a stronger Bell
argument excluding also these non-local theories. Taking into account all
possible theories, the conclusion of this stronger argument provably is the
strongest possible consequence from the violation of Bell inequalities on a
qualitative probabilistic level (given usual background assumptions). Among the
forbidden theories is a subset of outcome dependent theories showing that
outcome dependence is not sufficient for explaining a violation of Bell
inequalities. Non-local theories which can violate Bell inequalities (among
them quantum theory) are rather characterised by the fact that at least one of
the measurement outcomes in some sense (which is made precise)
probabilistically depends both on its local as well as on its distant
measurement setting ('parameter'). When Bell inequalities are found to be
violated, the true choice is not 'outcome dependence or parameter dependence'
but between two kinds of parameter dependences, one of them being what is
usually called 'parameter dependence'. Against the received view established by
Jarrett and Shimony that on a probabilistic level quantum non-locality amounts
to outcome dependence, this result confirms and makes precise Maudlin's claim
that some kind of parameter dependence is required.


title: Morse theory for the Hofer length functional

abstract:
  Following \cite{citeSavelyevVirtualMorsetheoryon$Omega$Ham$(Momega)$.}, we
develop here a connection between Morse theory for the (positive) Hofer length
functional $L: \Omega \text {Ham}(M, \omega) \to \mathbb{R}$, with
Gromov-Witten/Floer theory, for monotone symplectic manifolds $ (M, \omega) $.
This gives some immediate restrictions on the topology of the group of
Hamiltonian symplectomorphisms (possibly relative to the Hofer length
functional), and a criterion for non-existence of certain higher index
geodesics for the Hofer length functional. The argument is based on a certain
automatic transversality phenomenon which uses Hofer geometry to conclude
transversality and may be useful in other contexts. Strangely the monotone
assumption seems essential for this argument, as abstract perturbations
necessary for the virtual moduli cycle, decouple us from underlying Hofer
geometry, causing automatic transversality to break.


title: Field-theoretical study of the Bose polaron

abstract:
  We study the properties of the Bose polaron, an impurity strongly interacting
with a Bose-Einstein condensate, using a field-theoretic approach and make
predictions for the spectral function and various quasiparticle properties that
can be tested in experiment. We find that most of the spectral weight is
contained in a coherent attractive and a metastable repulsive polaron branch.
We show that the qualitative behavior of the Bose polaron is well described by
a non-selfconsistent T-matrix approximation by comparing analytical results to
numerical data obtained from a fully selfconsistent T-matrix approach. The
latter takes into account an infinite number of bosons excited from the
condensate.


title:
On a local-global principle for $H^3$ of function fields of surfaces
  over a finite field

abstract:
  Let K be the function field of a smooth projective surface over a finite
field. In this article, following the work of Parimala and Suresh, we establish
a local-global principle for the divisibility of elements in H^3(K,Z/l) by
elements in H^2(K,Z/l).


title: Simple Semigroup Graded Rings

abstract:
  We show that if $R$ is a, not necessarily unital, ring graded by a semigroup
$G$ equipped with an idempotent $e$ such that $G$ is cancellative at $e$, the
non-zero elements of $eGe$ form a hypercentral group and $R_e$ has a non-zero
idempotent $f$, then $R$ is simple if and only if it is graded simple and the
center of the corner subring $f R_{eGe} f$ is a field. This is a generalization
of a result of E. Jespers' on the simplicity of a unital ring graded by a
hypercentral group. We apply our result to partial skew group rings and obtain
necessary and sufficient conditions for the simplicity of a, not necessarily
unital, partial skew group ring by a hypercentral group. Thereby, we generalize
a very recent result of D. Gon\c{c}alves'. We also point out how E. Jespers'
result immediately implies a generalization of a simplicity result, recently
obtained by A. Baraviera, W. Cortes and M. Soares, for crossed products by
twisted partial actions.


title: Quantum single electron solitons near metal surface

abstract:
  A possibility of a quantum single electron soliton (QSES) formation in
structures with different dimensionality (0, 1, 2, and 3D) and spectrum
(parabolic and linear) placed near metal surface is discussed. These solitons
originate as solutions of the nonlinear Schrodinger equation allowing for
interaction with image charges in metal. The binding energy of those
quasi-particles could exceed the thermal energy at room temperature.


title: Interface states in CoFe2O4 spin-filter tunnel junctions

abstract:
  Spin-filter tunneling is a promising way to generate highly spin-polarized
current, a key component for spintronics applications. In this work we explore
the tunneling conductance across the spin-filter material CoFe2O4 interfaced
with Au electrodes, a geometry which provides nearly perfect lattice matching
at the CoFe2O4/Au(001) interface. Using density functional theory calculations
we demonstrate that interface states play a decisive role in controlling the
transport spin polarization in this tunnel junction. For a realistic CoFe2O4
barrier thickness, we predict a tunneling spin polarization of about -60%. We
show that this value is lower than what is expected based solely on
considerations of the spin-polarized band structure of CoFe2O4, and therefore
that these interface states can play a detrimental role. We argue this is a
rather general feature of ferrimagnetic ferrites and could make an important
impact on spin-filter tunneling applications.


title:
Update of the Binoth Les Houches Accord for a standard interface between
  Monte Carlo tools and one-loop programs

abstract:
  We present an update of the Binoth Les Houches Accord (BLHA) to standardise
the interface between Monte Carlo programs and codes providing one-loop matrix
elements.


title:
Field-induced superfluids and Bose liquids in Projected Entangled Pair
  States

abstract:
  In two-dimensional incompressible quantum spin liquids, a large enough
magnetic field generically induces "doping" of polarized S=1 triplons or S=1/2
spinons. We review a number of cases such as spin-3/2 AKLT or spin-1/2
Resonating Valence Bond (RVB) liquids where the Projected Entangled Pair States
(PEPS) framework provides very simple and comprehensive pictures. On the
bipartite honeycomb lattice, simple PEPS can describe Bose condensed triplons
(AKLT) or spinons (RVB) superfluids with transverse staggered (N\'eel) magnetic
order. On the Kagome lattice, doping the RVB state with deconfined spinons or
triplons (i.e. spinon bound pairs) yields uncondensed Bose liquids preserving
U(1) spin-rotation symmetry. We find that spinon (triplon) doping destroys
(preserves) the topological Z_2 symmetry of the underlying RVB state. We also
find that spinon doping induces longer range interactions in the entanglement
Hamiltonian, suggesting the emergence of (additive) log-corrections to the
entanglement entropy.


title: Regular quantum plasmons in segments of graphene nanoribbons

abstract:
  Graphene plasmons have advantages over noble metal plasmons, such as high
tunability and low loss. However, for graphene nanostructures smaller than 10
nm, little is known about their plasmons or whether a regular plasmonic
behavior exists, despite their potential applications. Here, we present
first-principles calculations of plasmon excitations in zigzag graphene
nanoribbon segments. Regular plasmonic behavior is found: Only one plasmon mode
exists in the low-energy regime (< 1.5 eV). The classical electrostatic scaling
law still approximately holds when the width (W) is larger than about 1.5 nm
but totally fails when W < 1.5 nm due to quantum effects. The scaling with
different doping densities shows that the plasmon is nearly free-electron
plasmon instead of Dirac plasmon.


title: Low Frequency Electronic Noise in Single-Layer MoS2 Transistors

abstract:
  Ubiquitous low frequency 1/f noise can be a limiting factor in the
performance and application of nanoscale devices. Here, we quantitatively
investigate low frequency electronic noise in single-layer transition metal
dichalcogenide MoS2 field-effect transistors. The measured 1/f noise can be
explained by an empirical formulation of mobility fluctuations with the Hooge
parameter ranging between 0.005 and 2.0 in vacuum (< 10-5 Torr). The
field-effect mobility decreased and the noise amplitude increased by an order
of magnitude in ambient conditions, revealing the significant influence of
atmospheric adsorbates on charge transport. In addition, single Lorentzian
generation-recombination noise was observed to increase by an order of
magnitude as the devices were cooled from 300 K to 6.5 K.


title: Palindrome Recognition In The Streaming Model

abstract:
  In the Palindrome Problem one tries to find all palindromes (palindromic
substrings) in a given string. A palindrome is defined as a string which reads
forwards the same as backwards, e.g., the string "racecar". A related problem
is the Longest Palindromic Substring Problem in which finding an arbitrary one
of the longest palindromes in the given string suffices. We regard the
streaming version of both problems. In the streaming model the input arrives
over time and at every point in time we are only allowed to use sublinear
space. The main algorithms in this paper are the following: The first one is a
one-pass randomized algorithm that solves the Palindrome Problem. It has an
additive error and uses $O(\sqrt n$) space. The second algorithm is a two-pass
algorithm which determines the exact locations of all longest palindromes. It
uses the first algorithm as the first pass. The third algorithm is again a
one-pass randomized algorithm, which solves the Longest Palindromic Substring
Problem. It has a multiplicative error using only $O(\log(n))$ space. We also
give two variants of the first algorithm which solve other related practical
problems.


title: Improved likelihood inference in generalized linear models

abstract:
  We address the issue of performing testing inference in generalized linear
models when the sample size is small. This class of models provides a
straightforward way of modeling normal and non-normal data and has been widely
used in several practical situations. The likelihood ratio, Wald and score
statistics, and the recently proposed gradient statistic provide the basis for
testing inference on the parameters in these models. We focus on the
small-sample case, where the reference chi-squared distribution gives a poor
approximation to the true null distribution of these test statistics. We derive
a general Bartlett-type correction factor in matrix notation for the gradient
test which reduces the size distortion of the test, and numerically compare the
proposed test with the usual likelihood ratio, Wald, score and gradient tests,
and with the Bartlett-corrected likelihood ratio and score tests. Our
simulation results suggest that the corrected test we propose can be an
interesting alternative to the other tests since it leads to very accurate
inference even for very small samples. We also present an empirical application
for illustrative purposes.


title:
Dirac Gauginos in Supersymmetry -- Suppressed Jets + MET Signals: A
  Snowmass Whitepaper

abstract:
  We consider the modifications to squark production in the presence of a
naturally heavier Dirac gluino. First generation squark production is highly
suppressed, providing an interesting but challenging signal find or rule out.
No dedicated searches for supersymmetry with a Dirac gluino have been
performed, however a reinterpretation of a "decoupled gluino" simplified model
suggests the bounds on a common first and second generation squark mass is much
smaller than in the MSSM: $\lsim 850$ GeV for a massless LSP, and no bound for
an LSP heavier than about 300 GeV. We compare and contrast the squark
production cross sections between a model with a Dirac gluino and one with a
Majorana gluino, updating earlier results in the literature to a $pp$ collider
operating at $\sqrt{s} = 14$ and 33 TeV. Associated production of squark+gluino
is likely very small at $\sqrt{s} = 14$ TeV, while is a challenging but
important signal at even higher energy $pp$ colliders. Several other salient
implications of Dirac gauginos are mentioned, with some thought-provoking
discussion as it regards the importance of the various experiments planned or
proposed.


title: Intersection local times for interlacements

abstract:
  We define renormalized intersection local times for random interlacements of
L\'evy processes in R^{d} and prove an isomorphism theorem relating
renormalized intersection local times with associated Wick polynomials.