title: Heterophilious dynamics enhances consensus

abstract:
  We review a general class of models for self-organized dynamics based on
alignment. The dynamics of such systems is governed solely by interactions
among individuals or "agents," with the tendency to adjust to their
`environmental averages'. This, in turn, leads to the formation of clusters,
e.g., colonies of ants, flocks of birds, parties of people, etc. A natural
question which arises in this context is to understand when and how clusters
emerge through the self-alignment of agents, and what type of "rules of
engagement" influence the formation of such clusters. Of particular interest to
us are cases in which the self-organized behavior tends to concentrate into one
cluster, reflecting a consensus of opinions, flocking or concentration of other
positions intrinsic to the dynamics.
  Many standard models for self-organized dynamics in social, biological and
physical science assume that the intensity of alignment increases as agents get
closer, reflecting a common tendency to align with those who think or act
alike. Moreover, "Similarity breeds connection," reflects our intuition that
increasing the intensity of alignment as the difference of positions decreases,
is more likely to lead to a consensus. We argue here that the converse is true:
when the dynamics is driven by local interactions, it is more likely to
approach a consensus when the interactions among agents \emph{increase} as a
function of their difference in position. \emph{Heterophily} --- the tendency
to bond more with those who are different rather than with those who are
similar, plays a decisive r\^{o}le in the process of clustering. We point out
that the number of clusters in heterophilious dynamics \emph{decreases} as the
heterophily dependence among agents increases. In particular, sufficiently
strong heterophilious interactions enhance consensus.


title: Pathway to the Square Kilometre Array - The German White Paper -

abstract:
  The Square Kilometre Array (SKA) is the most ambitious radio telescope ever
planned. With a collecting area of about a square kilometre, the SKA will be
far superior in sensitivity and observing speed to all current radio
facilities. The scientific capability promised by the SKA and its technological
challenges provide an ideal base for interdisciplinary research, technology
transfer, and collaboration between universities, research centres and
industry. The SKA in the radio regime and the European Extreme Large Telescope
(E-ELT) in the optical band are on the roadmap of the European Strategy Forum
for Research Infrastructures (ESFRI) and have been recognised as the essential
facilities for European research in astronomy.
  This "White Paper" outlines the German science and R&D interests in the SKA
project and will provide the basis for future funding applications to secure
German involvement in the Square Kilometre Array.


title:
A Macaulay2 package for characteristic classes and the topological Euler
  characteristic of complex projective schemes

abstract:
  The Macaulay2 package CharacteristicClasses provides commands for the
computation of the topological Euler characteristic, the degrees of the Chern
classes and the degrees of the Segre classes of a closed subscheme of complex
projective space. The computations can be done both symbolically and
numerically, the latter using an interface to Bertini. We provide some
background of the implementation and show how to use the package with the help
of examples.


title:
The role of screening in the density functional applied on transition
  metal defects in semiconductors

abstract:
  We study selected transition metal related point defects in silicon and
silicon carbide semiconductors by a range separated hybrid density functional
(HSE06). We find that HSE06 does not fulfill the generalized Koopmans' Theorem
for every defect which is due to the self-interaction error in the functional
in such cases. Restoring the so-called generalized Koopmans' Condition with a
simple correction in the functional can eliminate this error, and brings the
calculated charge transition levels remarkably close to the experimental data
as well as to the calculated quasi-particle levels from many-body perturbation
theory.


title:
Multiple Bernoulli series and volumes of moduli spaces of flat bundles
  over surfaces

abstract:
  Using Szenes formula for multiple Bernoulli series we explain how to compute
Witten series associated to classical Lie algebras. Particular instances of
these series compute volumes of moduli spaces of flat bundles over surfaces,
and also certain multiple zeta values.


title:
An algorithm for computing the topological Euler characteristic of
  complex projective varieties

abstract:
  We present an algorithm for the symbolic and numerical computation of the
degrees of the Chern-Schwartz-MacPherson classes of a closed subvariety of
projective space P^n. As the degree of the top Chern-Schwartz-MacPherson class
is the topological Euler characteristic, this also yields a method to compute
the topological Euler characteristic of projective varieties. The method is
based on Aluffi's symbolic algorithm to compute degrees of
Chern-Schwartz-MacPherson classes, a symbolic method to compute degrees of
Segre classes, and the regenerative cascade by Hauenstein, Sommese and Wampler.
The new algorithm complements the existing algorithms. We also give an example
for using a theorem by Huh to compute an invariant from algebraic statistics,
the maximum likelihood degree of an implicit model.


title:
The subdwarf B star SB 290 - A fast rotator on the extreme horizontal
  branch

abstract:
  Hot subdwarf B stars (sdBs) are evolved core helium-burning stars with very
thin hydrogen envelopes. In order to form an sdB, the progenitor has to lose
almost all of its hydrogen envelope right at the tip of the red giant branch.
In close binary systems, mass transfer to the companion provides the
extraordinary mass loss required for their formation. However, apparently
single sdBs exist as well and their formation is unclear since decades. The
merger of helium white dwarfs leading to an ignition of core helium-burning or
the merger of a helium core and a low mass star during the common envelope
phase have been proposed. Here we report the discovery of SB 290 as the first
apparently single fast rotating sdB star located on the extreme horizontal
branch indicating that those stars may form from mergers.


title: Imitation dynamics in a game of traffic

abstract:
  We study a model of traffic where drivers adopt different behavioral
strategies. These can be cooperative or defective according to a driver abiding
or not by a traffic rule. Drivers can change their strategy by imitating the
majority, with a rule that depends on the strategies with which they have
interacted. These interactions occur at intersections, where vehicles pay a
temporal cost according to their strategy. We analyze the conditions under
which different strategy compositions represent an advantage in the system
velocity. We found that the cooperators' mean speed is higher than the
defectors' even when the vehicle density is large. However, defectors can
obtain benefits in their mean speed when they are a minority in an essentially
cooperative population. The presence of a core of educated drivers, who persist
firmly in a cooperative behavior, optimizes the speed in the system, especially
for intermediate values of vehicular density and higher temporal costs.


title:
Energy-Efficient Scheduling with Time and Processors Eligibility
  Restrictions

abstract:
  While previous work on energy-efficient algorithms focused on assumption that
tasks can be assigned to any processor, we initially study the problem of task
scheduling on restricted parallel processors. The objective is to minimize the
overall energy consumption while speed scaling (SS) method is used to reduce
energy consumption under the execution time constraint (Makespan $C_{max}$). In
this work, we discuss the speed setting in the continuous model that processors
can run at arbitrary speed in $[s_{min},s_{max}]$. The energy-efficient
scheduling problem, involving task assignment and speed scaling, is inherently
complicated as it is proved to be NP-Complete. We formulate the problem as an
Integer Programming (IP) problem. Specifically, we devise a polynomial time
optimal scheduling algorithm for the case tasks have a uniform size. Our
algorithm runs in $O(mn^3logn)$ time, where $m$ is the number of processors and
$n$ is the number of tasks. We then present a polynomial time algorithm that
achieves an approximation factor of $2^{\alpha-1}(2-\frac{1}{m^{\alpha}})$
($\alpha$ is the power parameter) when the tasks have arbitrary size work.
Experimental results demonstrate that our algorithm could provide an efficient
scheduling for the problem of task scheduling on restricted parallel
processors.


title: An exact solution of the Dirac equation with CP violation

abstract:
  We consider Yukawa theory in which the fermion mass is induced by a Higgs
like scalar. In our model the fermion mass exhibits a temporal dependence,
which naturally occurs in the early Universe setting. Assuming that the complex
fermion mass changes as a tanh-kink, we construct an exact, helicity
conserving, CP-violating solution for the positive and negative frequency
fermionic mode functions, which is valid both in the case of weak and strong CP
violation. Using this solution we then study the fermionic currents both in the
initial vacuum and finite density/temperature setting. Our result shows that,
due to a potentially large state squeezing, fermionic currents can exhibit a
large oscillatory magnification. Having in mind applications to electroweak
baryogenesis, we then compare our exact results with those obtained in a
gradient approximation. Even though the gradient approximation does not capture
the oscillatory effects of squeezing, it describes quite well the averaged
current, obtained by performing a mode sum. Our main conclusion is: while the
agreement with the semiclassical force is quite good in the thick wall regime,
the difference is sufficiently significant to motivate a more detailed
quantitative study of baryogenesis sources in the thin wall regime in more
realistic settings.


title: Results on $\beta$ from BABAR

abstract:
  We present recent results from the BABAR collaboration of the time-dependent
analysis of B0 meson decays to KsKsKs, the Dalitz-plot analysis of B0->K+K-Ks
and the time-dependent CP asymmetry of partially reconstructed B0->D*+D*-
decays.


title:
The relationship between semi-classical Laguerre polynomials and the
  fourth Painlev\'e equation

abstract:
  We discuss the relationship between the recurrence coefficients of orthogonal
polynomials with respect to a semi-classical Laguerre weight and classical
solutions of the fourth Painlev\'e equation. We show that the coefficients in
these recurrence relations can be expressed in terms of Wronskians of parabolic
cylinder functions which arise in the description of special function solutions
of the fourth Painlev\'e equation.


title:
Superconductivity and Strong Non-Fermi-Liquid Behavior in Single-Crystal
  Ir3Te8

abstract:
  We observe superconductivity below a critical temperature TC = 1.8 K in
single-crystal Ir3Te8, which also exhibits normal-state diamagnetism and a
linear temperature dependence of electrical resistivity for a wide temperature
interval, 20 K < T < 700 K. Single-crystal Ir3Te8 also undergoes a structural
phase transition at TS = 350 K from a cubic (above TS) to a rhombohedral
lattice below TS. Our first-principles electronic structure calculations reveal
two bands crossing the Fermi level; despite the three-dimensional lattice, one
band is quasi-two-dimensional, and is responsible for the observed diamagnetism
and structure transition. The strong non-Fermi-liquid behavior characterized by
the observed linearity in resistivity in such a nonmagnetic state suggests
novel physics in this newly discovered superconductor.


title:
Incorporating Voice Permutations into the Theory of Neo-Riemannian
  Groups and Lewinian Duality

abstract:
  A familiar problem in neo-Riemannian theory is that the P, L, and R
operations defined as contextual inversions on pitch-class segments do not
produce parsimonious voice leading. We incorporate permutations into
T/I-PLR-duality to resolve this issue and simultaneously broaden the
applicability of this duality. More precisely, we construct the dual group to
the permutation group acting on n-tuples with distinct entries, and prove that
the dual group to permutations adjoined with a group G of invertible affine
maps Z12 -> Z12 is the internal direct product of the dual to permutations and
the dual to G. Musical examples include Liszt, R. W. Venezia, S. 201 and
Schoenberg, String Quartet Number 1, Opus 7. We also prove that the Fiore--Noll
construction of the dual group in the finite case works, and clarify the
relationship of permutations with the RICH transformation.


title:
When you talk about "Information processing" what actually do you have
  in mind?

abstract:
  "Information Processing" is a recently launched buzzword whose meaning is
vague and obscure even for the majority of its users. The reason for this is
the lack of a suitable definition for the term "information". In my attempt to
amend this bizarre situation, I have realized that, following the insights of
Kolmogorov's Complexity theory, information can be defined as a description of
structures observable in a given data set. Two types of structures could be
easily distinguished in every data set - in this regard, two types of
information (information descriptions) should be designated: physical
information and semantic information. Kolmogorov's theory also posits that the
information descriptions should be provided as a linguistic text structure.
This inevitably leads us to an assertion that information processing has to be
seen as a kind of text processing. The idea is not new - inspired by the
observation that human information processing is deeply rooted in natural
language handling customs, Lotfi Zadeh and his followers have introduced the
so-called "Computing With Words" paradigm. Despite of promotional efforts, the
idea is not taking off yet. The reason - a lack of a coherent understanding of
what should be called "information", and, as a result, misleading research
roadmaps and objectives. I hope my humble attempt to clarify these issues would
be helpful in avoiding common traps and pitfalls.


title:
Spatially resolved investigation of strain and composition variations in
  (In,Ga)N/GaN epilayers

abstract:
  The strain state and composition of a 400 nm thick (In,Ga)N layer grown by
metal-organic chemical vapor deposition on a GaN template are investigated by
spatially integrated x-ray diffraction and cathodoluminescence (CL)
spectroscopy as well as by spatially resolved CL and energy dispersive x-ray
analysis. The CL investigations confirm a process of strain relaxation
accompanied by an increasing indium content toward the surface of the (In,Ga)N
layer, which is known as the compositional pulling effect. Moreover, we
identify the strained bottom, unstrained top, and gradually relaxed
intermediate region of the (In,Ga)N layer. In addition to an increase of the
indium content along the growth direction, the strain relaxation leads to an
enhancement of the lateral variations of the indium distribution toward the
surface.


title: Topological quantum memory interfacing atomic and superconducting qubits

abstract:
  We propose a scheme to manipulate a topological spin qubit which is realized
with cold atoms in a one-dimensional optical lattice. In particular, by
introducing a quantum opto-electro-mechanical interface, we are able to first
transfer a superconducting qubit state to an atomic qubit state and then to
store it into the topological spin qubit. In this way, an efficient topological
quantum memory could be constructed for the superconducting qubit. Therefore,
we can consolidate the advantages of both the noise resistance of the
topological qubits and the scalability of the superconducting qubits in this
hybrid architecture.


title: Panchromatic fits to the Globular Cluster NGC 6366

abstract:
  We present panchromatic isochrone fits to the color magnitude data of the
globular cluster NGC 6366, based on HST ACS/WFC and SOAR photometric data.
Before performing the isochrone fits, we corrected the photometric data for
differential reddening and calculated the mean ridge line of the color
magnitude diagrams. We compared the isochrones of Dartmouth Stellar Evolution
Database and PAdova and TRieste Stellar Evolution Code (with microscopic
diffusion starting on the main sequence). Based on previous determinations of
the metallicity of this cluster we test it from [Fe/H]=-1.00 to [Fe/H]= -0.50,
and the age from 9 to 13 Gyrs. The uncertainties do not decrease when we fit
simultaneous colors. We also find that the Dartmouth Stellar Evolution Database
isochrones have a better fit in the sub giant branch and low main sequence than
the PAdova and TRieste Stellar Evolution Code. Considering the most recent
spectroscopic determination of the metallicity ([Fe/H]= -0.67), we find
E(B-V)=0.69+/-0.02, (m-M)_V=15.02+/-0.07 and 11+/-2 Gyr for NGC 6366.


title:
Lattice Study of the Extent of the Conformal Window in Two-Color
  Yang-Mills Theory

abstract:
  We perform a lattice calculation of the Schr\"odinger functional running
coupling in SU(2) Yang-Mills theory with six massless Wilson fermions in the
fundamental representation. The aim of this work is to determine whether the
above theory has an infrared fixed point. Due to sensitivity of the $SF$
renormalized coupling to the tuning of the fermion bare mass we were unable to
reliably extract the running coupling for stronger bare couplings.


title: Strong Nernst-Ettingshausen effect in folded graphene

abstract:
  We study electronic transport in graphene under the influence of a
transversal magnetic field $\f{B}(\f{r})=B(x)\f{e}_z$ with the asymptotics
$B(x\to\pm\infty)=\pm B_0$, which could be realized via a folded graphene sheet
in a constant magnetic field, for example. By solving the effective Dirac
equation, we find robust modes with a finite energy gap which propagate along
the fold -- where particles and holes move in opposite directions. Exciting
these particle-hole pairs with incident photons would then generate a nearly
perfect charge separation and thus a strong magneto-thermoelectric
(Nernst-Ettingshausen) or magneto-photoelectric effect -- even at room
temperature.


title: Koide's Z_3-symmetric parametrization, quark masses and mixings

abstract:
  The sets of charged-lepton (L) and quark (D,U) masses may be parametrized in
a Z_3-symmetric language appropriate for the discussion of Koide's formula.
Experiment suggests that at the low-energy scale the relevant phase parameters
\delta_f take on possibly exact values of \delta_L=3\delta_D/2=3\delta_U=2/9.
For k_f (the other parameter relevant for the pattern of masses), a similarly
simple expression (k_L=1) is known for charged leptons only. Using the
Fritzsch-Xing decomposition of quark-mixing matrices, we show that the
suggested pattern of low-energy quark masses is consistent with an earlier
conjecture that k_{D,U} \approx 1 in the weak basis.


title: Non-parametric Bayesian modelling of digital gene expression data

abstract:
  Next-generation sequencing technologies provide a revolutionary tool for
generating gene expression data. Starting with a fixed RNA sample, they
construct a library of millions of differentially abundant short sequence tags
or "reads", which constitute a fundamentally discrete measure of the level of
gene expression. A common limitation in experiments using these technologies is
the low number or even absence of biological replicates, which complicates the
statistical analysis of digital gene expression data. Analysis of this type of
data has often been based on modified tests originally devised for analysing
microarrays; both these and even de novo methods for the analysis of RNA-seq
data are plagued by the common problem of low replication. We propose a novel,
non-parametric Bayesian approach for the analysis of digital gene expression
data. We begin with a hierarchical model for modelling over-dispersed count
data and a blocked Gibbs sampling algorithm for inferring the posterior
distribution of model parameters conditional on these counts. The algorithm
compensates for the problem of low numbers of biological replicates by
clustering together genes with tag counts that are likely sampled from a common
distribution and using this augmented sample for estimating the parameters of
this distribution. The number of clusters is not decided a priori, but it is
inferred along with the remaining model parameters. We demonstrate the ability
of this approach to model biological data with high fidelity by applying the
algorithm on a public dataset obtained from cancerous and non-cancerous neural
tissues.


title: Full-sky CMB lensing reconstruction in presence of sky-cuts

abstract:
  We consider the reconstruction of the CMB lensing potential and its power
spectrum of the full sphere in presence of sky-cuts due to point sources and
Galactic contaminations. Those two effects are treated separately. Small
regions contaminated by point sources are filled in using Gaussian constrained
realizations. The Galactic plane is simply masked using an apodized mask before
lensing reconstruction. This algorithm recovers the power spectrum of the
lensing potential with no significant bias.


title: Sub-exponential mixing of random billiards driven by thermostats

abstract:
  We study the class of open continuous-time mechanical particle systems
introduced in the paper by Khanin and Yarmola [Ergodic Properties of Random
Billiards Driven by Thermostats. Commun. Math. Phys. 320, no. 1, 121-147
(2013)]. Using the discrete-time results from that paper we demonstrate
rigorously that, in continuous time, a unique steady state exists and is
sub-exponentially mixing. Moreover, all initial distributions converge to the
steady state and, for a large class of initial distributions, convergence to
the steady state is sub-exponential. The main obstacle to exponential
convergence is the existence of slow particles in the system.


title:
Multiple Structures with Arbitrarily Large Projective Dimension on
  Linear Subspaces

abstract:
  Let $K$ be an algebraically closed field. There has been much interest in
characterizing multiple structures in $\P^n_K$ defined on a linear subspace of
small codimension under additional assumptions (e.g. Cohen-Macaulay). We show
that no such finite characterization of multiple structures is possible if one
only assumes Serre's $(S_1)$ property holds. Specifically, we prove that for
any positive integers $h, e \ge 2$ with $(h,e) \neq (2,2)$ and $p \ge 5$ there
is a homogeneous ideal $I$ in a polynomial ring over $K$ such that (1) the
height of $I$ is $h$, (2) the Hilbert-Samuel multiplicity of $R/I$ is $e$, (3)
the projective dimension of $R/I$ is at least $p$ and (4) the ideal $I$ is
primary to a linear prime $(x_1,..., x_h)$. This result is in stark contrast to
Manolache's characterization of Cohen-Macaulay multiple structures in
codimension 2 and multiplicity at most 4 and also to Engheta's characterization
of unmixed ideals of height 2 and multiplicity 2.


title:
Renormalization Group approach to Gravity: the running of G and L inside
  galaxies and additional details on the elliptical NGC 4494

abstract:
  We explore the phenomenology of nontrivial quantum effects on low-energy
gravity. These effects come from the running of the gravitational coupling
parameter G and the cosmological constant L in the Einstein-Hilbert action, as
induced by the Renormalization Group (RG). The Renormalization Group corrected
General Relativity (RGGR model) is used to parametrize these quantum effects,
and it is assumed that the dominant dark matter-like effects inside galaxies is
due to these nontrivial RG effects. Here we present additional details on the
RGGR model application, in particular on the Poisson equation extension that
defines the effective potential, also we re-analyse the ordinary elliptical
galaxy NGC 4494 using a slightly different model for its baryonic contribution,
and explicit solutions are presented for the running of G and L. The values of
the NGC 4494 parameters as shown here have a better agreement with the general
RGGR picture for galaxies, and suggest a larger radial anisotropy than the
previously published result.


title:
Temperature dependence of hole spin coherence in (In,Ga)As quantum dots
  measured by mode-locking and echo techniques

abstract:
  The temperature dependence of the coherence time of hole spins confined in
self-assembled (In,Ga)As/GaAs quantum dots is studied by spin mode-locking and
spin echo techniques. Coherence times limited to about a \mu s are measured for
temperatures below 8 K. For higher temperatures a fast drop occurs down to a
few ns over a 10 K range. The hole-nuclear hyperfine interaction appears too
weak to account for these limitations. We suggest that spin-orbit related
interactions are the decisive sources for hole spin decoherence.


title: Scaling analyses based on wavelet transforms for the Talbot effect

abstract:
  The fractal properties of the transverse Talbot images are analysed with two
well-known scaling methods, the wavelet transform modulus maxima (WTMM) and the
wavelet transform multifractal detrended fluctuation analysis (WT-MFDFA). We
use the widths of the singularity spectra, Delta alpha=alpha_H-alpha_min, as a
characteristic feature of these Talbot images. The tau scaling exponents of the
q moments are linear in q within the two methods, which proves the
monofractality of the transverse diffractive paraxial field in the case of
these images


title: Turbulent transport in radiative zones of stars

abstract:
  Context. In stellar interiors, rotation is able to drive turbulent motions,
and the related transport processes have a significant influence on the
evolution of stars. Turbulent mixing in the radiative zones is currently taken
into account in stellar evolution models through a set of diffusion
coefficients that are generally poorly constrained.
  Aims. We want to constrain the form of one of them, the radial diffusion
coefficient of chemical elements due to the turbulence driven by radial
differential rotation, derived by Zahn (1974, 1992) on phenomenological grounds
and largely used since.
  Methods. We performed local, direct numerical simulations of stably
stratified homogeneous sheared turbulence using the Boussinesq approximation.
The domain of low P\'eclet numbers found in stellar interiors is currently
inaccessible to numerical simulations without approximation. It is explored
here thanks to a suitable asymptotic form of the Boussinesq equations. The
turbulent transport of a passive scalar is determined in statistical steady
states.
  Results. We provide a first quantitative determination of the turbulent
diffusion coefficient and find that the form proposed by Zahn is in good
agreement with the results of the numerical simulations.


title: Comodule Hom-coalgebras

abstract:
  We introduce the concept of comodule Hom-coalgebras and show that comodule
Hom-coalgebras can be deformed from comodule coalgebras via endomorphisms.


title: Vud from Nuclear Mirror Transitions

abstract:
  We review the determination of Vud from nuclear mirror transitions and
describe current experimental and theoretical efforts aimed at improving its
precision.


title: A Proof of Radford's Biproduct Theorem by Using Braided Diagrams

abstract:
  We give a proof of the Radford's Biproduct Theorem in S. Montgomery's book
[Hopf Algebras and Their Actions on Rings, CBMS 82, AMS,1993.] by using Majid's
braided diagrams method and Yu.Bespalov and V. Lyubashenko's "t-angles.sty"
package.


title: A Search-free DOA Estimation Algorithm for Coprime Arrays

abstract:
  Recently, coprime arrays have been in the focus of research because of their
potential in exploiting redundancy in spanning large apertures with fewer
elements than suggested by theory. A coprime array consists of two uniform
linear subarrays with inter-element spacings $M\lambda/2$ and $N\lambda/2$,
where $M$ and $N$ are coprime integers and $\lambda$ is the wavelength of the
signal. In this paper, we propose a fast search-free method for
direction-of-arrival (DOA) estimation with coprime arrays. It is based on the
use of methods that operate on the uniform linear subarrays of the coprime
array and that enjoy many processing advantages. We first estimate the DOAs for
each uniform linear subarray separately and then combine the estimates from the
subarrays. For combining the estimates, we propose a method that projects the
estimated point in the two-dimensional plane onto one-dimensional line segments
that correspond to the entire angular domain. By doing so, we avoid the search
step and consequently, we greatly reduce the computational complexity of the
method. We demonstrate the performance of the method with computer simulations
and compare it with that of the FD-root MUSIC method.


title: Emergent non-trivial lattices for topological insulators

abstract:
  Materials with non-trivial lattice geometries allow for the creation of
exotic states of matter like topologically insulating states. Therefore
searching for such materials is an important aspect of current research in
solid-state physics. In the field of ultracold gases there are ongoing studies
aiming to create non-trivial lattices using optical means. In this paper we
study two species of fermions trapped in a square optical lattice and show how
non-trivial lattices can emerge due to strong interaction between atoms. We
theoretically investigate regimes of tunable parameters in which such
self-assembly may take place and describe the necessary experimental
conditions. Moreover we discuss the possibility of such emergent lattices
hosting topologically insulating states.


title: On the Product Rule for Classification Problems

abstract:
  We discuss theoretical aspects of the product rule for classification
problems in supervised machine learning for the case of combining classifiers.
We show that (1) the product rule arises from the MAP classifier supposing
equivalent priors and conditional independence given a class; (2) under some
conditions, the product rule is equivalent to minimizing the sum of the squared
distances to the respective centers of the classes related with different
features, such distances being weighted by the spread of the classes; (3)
observing some hypothesis, the product rule is equivalent to concatenating the
vectors of features.


title: Temporal Wilson loop in the Hamiltonian approach in Coulomb gauge

abstract:
  We investigate the temporal Wilson loop using the Hamiltonian approach to
Yang-Mills theory. In simple cases such as the Abelian theory or the
non-Abelian theory in (1+1) dimensions, the known results can be derived using
unitary transformations to take care of time evolution. Alternatively, the
exact solution can also be found in Coulomb gauge using the exact ground state
wave functional which is known explicitly in these simple cases. The Coulomb
gauge technique can also be applied to the more realistic case of Yang-Mills
theory in (3+1) dimensions, where one has to rely on the approximate vacuum
wave functional obtained e.g. in recent variational approaches. We use this
formulation to compute the temporal Wilson loop in (3+1) dimensional Yang-Mills
theory, and find that the Wilson and Coulomb string tension agree within this
approximation scheme. Possible improvements of these findings are briefly
discussed.


title: Tomonaga-Luttinger physics in electronic quantum circuits

abstract:
  In one-dimensional conductors, interactions result in correlated electronic
systems. At low energy, a hallmark signature of the so-called
Tomonaga-Luttinger liquids (TLL) is the universal conductance curve predicted
in presence of an impurity. A seemingly different topic is the quantum laws of
electricity, when distinct quantum conductors are assembled in a circuit. In
particular, the conductances are suppressed at low energy, a phenomenon called
dynamical Coulomb blockade (DCB). Here we investigate the conductance of
mesoscopic circuits constituted by a short single-channel quantum conductor in
series with a resistance, and demonstrate a proposed link to TLL physics. We
reformulate and establish experimentally a recently derived phenomenological
expression for the conductance using a wide range of circuits, including carbon
nanotube data obtained elsewhere. By confronting both conductance data and
phenomenological expression with the universal TLL curve, we demonstrate
experimentally the predicted mapping between DCB and the transport across a TLL
with an impurity.


title:
Random cascade model in the limit of infinite integral scale as the
  exponential of a non-stationary $1/f$ noise. Application to volatility
  fluctuations in stock markets

abstract:
  In this paper we propose a new model for volatility fluctuations in financial
time series. This model relies on a non-stationary gaussian process that
exhibits aging behavior. It turns out that its properties, over any finite time
interval, are very close to continuous cascade models. These latter models are
indeed well known to reproduce faithfully the main stylized facts of financial
time series. However, it involve a large scale parameter (the so-called
"integral scale" where the cascade is initiated) that is hard to interpret in
finance. Moreover the empirical value of the integral scale is in general
deeply correlated to the overall length of the sample. This feature is
precisely predicted by our model that turns out, as illustrated on various
examples from daily stock index data, to quantitatively reproduce the empirical
observations.


title: Semisimple Hopf actions on commutative domains

abstract:
  Let H be a semisimple (so, finite dimensional) Hopf algebra over an
algebraically closed field k of characteristic zero and let A be a commutative
domain over k. We show that if A arises as an H-module algebra via an inner
faithful H-action, then H must be a group algebra. This answers a question of
E. Kirkman and J. Kuzmanovich and partially answers a question of M. Cohen.
  The main results of this article extend to working over k of positive
characteristic. On the other hand, we obtain results on Hopf actions on Weyl
algebras as a consequence of the main theorem.


title:
Stone-Wales defects can cause a metal-semiconductor transition in carbon
  nanotubes depending on their orientation

abstract:
  It has been shown that the two different orientations of Stone-Wales (SW)
defects, i.e. longitudinal and circumferential SW defects, on carbon nanotubes
(CNTs) result in two different electronic structures. Based on density
functional theory we have shown that the longitudinal SW defects do not open a
bandgap near the Fermi energy, while a relatively small bandgap emerges in
tubes with circumferential defects. We argue that the bandgap opening in the
presence of circumferential SW defects is a consequence of long-range symmetry
breaking which can spread all the way along the tube. Specifically, the
distribution of contracted and stretched bond lengths due to the presence of
defects, and hopping energies for low-energy electrons, i.e. the 2pz electrons,
show two different patterns for the two types of defects. Interplay between the
geometric features and the electronic properties of the tubes have also been
studied for different defect concentrations. Considering $\pi$-orbital charge
density, it has also been shown that the deviations of bond lengths from their
relaxed length result in different doping for two defect orientations around
the defects -- electron-rich for a circumferential defect and hole-rich for a
longitudinal one. We have also shown that, in the tubes having both types of
defects, circumferential defects would dominate and impose their electronic
properties.


title: Confinement from Correlation Functions

abstract:
  We compute the Polyakov loop potential in Yang--Mills theory from the fully
dressed primitively divergent correlation functions only. This is done in a
variety of functional approaches ranging from functional renormalisation group
equations over Dyson--Schwinger equations to two-particle irreducible
functionals. We present a confinement criterion that links the infrared
behaviour of propagators and vertices to the Polyakov loop expectation value.
The present work extends the works of [1-3] to general functional methods and
sharpens the confinement criterion presented there. The computations are based
on the thermal correlation functions in the Landau gauge calculated in [4-6].


title:
Imaging the antiferromagnetic to ferromagnetic first order phase
  transition of FeRh

abstract:
  The antiferromagnetic (AFM) to ferromagnetic (FM) first order phase
transition of an epitaxial FeRh thin-film has been studied with x-ray magnetic
circular dichroism using photoemission electron microscopy. The FM phase is
magnetized in-plane due to shape anisotropy, but the magnetocrystalline
anisotropy is negligible and there is no preferred in-plane magnetization
direction. When heating through the AFM to FM phase transition the nucleation
of the FM phase occurs at many independent nucleation sites with random domain
orientation. The domains subsequently align to form the final FM domain
structure. We observe no pinning of the FM domain structure.


title: Colour-Kinematics Duality for One-Loop Rational Amplitudes

abstract:
  Colour-kinematics duality is the conjecture of a group theory-like structure
for the kinematic dependence of scattering amplitudes in gauge theory and
gravity. This structure has been verified at tree level in various ways, but
similar progress has been lacking at loop level, where the power of the duality
would be most significant. Here we explore colour-kinematics duality at one
loop using the self-dual sector as a starting point. The duality is shown to
exist in pure Yang-Mills theory for two infinite classes of amplitudes:
amplitudes with any number of particles either all of the same helicity or with
one particle helicity opposite the rest. We provide a simple Lagrangian-based
argument in favour of the double copy relation between gauge theory and gravity
amplitudes in these classes, and provide some explicit examples. We further
discuss aspects of the duality which persist after integration, leading to
relations among partial amplitudes. Finally, we describe form factors in the
self-dual theory at tree level which also satisfy the duality.


title:
Exact higher-spin symmetry in CFT: free fermion correlators from
  Vasiliev Theory

abstract:
  N-point correlation functions of conserved currents and weight-two scalar
operators of the three-dimensional free fermion vector model are found as
invariants of the higher-spin symmetry in four-dimensional AdS. These are the
correlators of the unbroken Vasiliev higher-spin theory. The results extend the
recent work arXiv:1210.7963 and are complementary to arXiv:1301.3123 where the
correlators were computed entirely on the boundary.


title: Some Notes on Blinded Sample Size Re-Estimation

abstract:
  This note investigates a number of scenarios in which unadjusted testing
following a blinded sample size re-estimation leads to type I error violations.
For superiority testing, this occurs in certain small-sample borderline cases.
We discuss a number of alternative approaches that keep the type I error rate.
The paper also gives a reason why the type I error inflation in the superiority
context might have been missed in previous publications and investigates why it
is more marked in case of non-inferiority testing.


title: Herded Gibbs Sampling

abstract:
  The Gibbs sampler is one of the most popular algorithms for inference in
statistical models. In this paper, we introduce a herding variant of this
algorithm, called herded Gibbs, that is entirely deterministic. We prove that
herded Gibbs has an $O(1/T)$ convergence rate for models with independent
variables and for fully connected probabilistic graphical models. Herded Gibbs
is shown to outperform Gibbs in the tasks of image denoising with MRFs and
named entity recognition with CRFs. However, the convergence for herded Gibbs
for sparsely connected probabilistic graphical models is still an open problem.


title:
Error estimates and specification parameters for functional
  renormalization

abstract:
  We present a strategy for estimating the error of truncated functional flow
equations. While the basic functional renormalization group equation is exact,
approximated solutions by means of truncations do not only depend on the choice
of the retained information, but also on the precise definition of the
truncation. Therefore, results depend on specification parameters that can be
used to quantify the error of a given truncation. We demonstrate this for the
BCS-BEC crossover in ultracold atoms. Within a simple truncation the precise
definition of the frequency dependence of the truncated propagator affects the
results, indicating a shortcoming of the choice of a frequency independent
cutoff function.


title:
Rydberg atoms with a reduced sensitivity to dc and low-frequency
  electric fields

abstract:
  A non-resonant microwave dressing field at 38.465 GHz was used to eliminate
the static electric dipole moment difference between the $49s_{1/2}$ and
$48s_{1/2}$ Rydberg states of $^{87}$Rb in dc fields of approximately 1 V/cm.
The reduced susceptibility to electric field fluctuations was measured using
2-photon microwave spectroscopy. An anomalous spectral doublet is attributed to
polarization ellipticity in the dressing field. The demonstrated ability to
inhibit static dipole moment differences --- while retaining sensitivity to
high frequency fields --- is applicable to sensors and/or quantum devices using
Rydberg atoms.


title: Affinity Weighted Embedding

abstract:
  Supervised (linear) embedding models like Wsabie and PSI have proven
successful at ranking, recommendation and annotation tasks. However, despite
being scalable to large datasets they do not take full advantage of the extra
data due to their linear nature, and typically underfit. We propose a new class
of models which aim to provide improved performance while retaining many of the
benefits of the existing class of embedding models. Our new approach works by
iteratively learning a linear embedding model where the next iteration's
features and labels are reweighted as a function of the previous iteration. We
describe several variants of the family, and give some initial results.


title:
External field control of spin-dependent rotational decoherence of
  ultracold polar molecules

abstract:
  We determine trapping conditions for ultracold polar molecules, where pairs
of internal states experience identical trapping potentials. Such conditions
could ensure that detrimental effects of inevitable inhomogeneities across an
ultracold sample are significantly reduced. In particular, we investigate the
internal rovibronic and hyperfine quantum states of ultracold fermionic
ground-state $^{40}$K$^{87}$Rb polar molecules, when static magnetic, static
electric, and trapping laser fields are simultaneously applied. Understanding
the effect of changing the relative orientation or polarization of these three
fields is of crucial importance for creation of decoherence-free subspaces
built from two or more rovibronic states. Moreover, we evaluate the induced
dipole moment of the molecule in the presence of these fields, which will allow
control of interactions between molecules in different sites of an optical
lattice and study the influence of the interaction anisotropy on the ability to
entangle polar molecules.


title: Diversity and no arbitrage

abstract:
  A stock market is called diverse if no stock can dominate the market in terms
of relative capitalization. On one hand, this natural property leads to
arbitrage in diffusion models under mild assumptions. On the other hand, it is
also easy to construct diffusion models which are both diverse and free of
arbitrage. Can one tell whether an observed diverse market admits arbitrage?
  In the present paper we argue that this may well be impossible by proving
that the known examples of diverse markets in the literature (which do admit
arbitrage) can be approximated uniformly (on the logarithmic scale) by models
which are both diverse and arbitrage-free.


title: EVH Black Hole Solutions With Higher Derivative Corrections

abstract:
  We analyze the effect of higher derivative corrections to the near horizon
geometry of the extremal vanishing horizon (EVH) black hole solutions in four
dimensions. We restrict ourselves to the Gauss-Bonnet correction with a
dilation dependent coupling in an Einstein Maxwell dilaton theory. This action
may represent the effective action as it arises in tree level heterotic string
theory compactified to four dimensions or the K3 compactification of type II
string theory. We show that EVH black holes, in this theory, develop an AdS3
throat in their near horizon geometry.


title: JPCam: A 1.2Gpixel camera for the J-PAS survey

abstract:
  JPCam is a 14-CCD mosaic camera, using the new e2v 9k-by-9k 10microm-pixel
16-channel detectors, to be deployed on a dedicated 2.55m wide-field telescope
at the OAJ (Observatorio Astrofisico de Javalambre) in Aragon, Spain. The
camera is designed to perform a Baryon Acoustic Oscillations (BAO) survey of
the northern sky. The J-PAS survey strategy will use 54 relatively narrow-band
(~13.8nm) filters equi-spaced between 370 and 920nm plus 3 broad-band filters
to achieve unprecedented photometric red-shift accuracies for faint galaxies
over ~8000 square degrees of sky. The cryostat, detector mosaic and read
electronics is being supplied by e2v under contract to J-PAS while the
mechanical structure, housing the shutter and filter assembly, is being
designed and constructed by a Brazilian consortium led by INPE (Instituto
Nacional de Pesquisas Espaciais). Four sets of 14 filters are placed in the
ambient environment, just above the dewar window but directly in line with the
detectors, leading to a mosaic having ~10mm gaps between each CCD. The massive
500mm aperture shutter is expected to be supplied by the Argelander-Institut
fur Astronomie, Bonn. We will present an overview of JPCam, from the filter
configuration through to the CCD mosaic camera. A brief outline of the main
J-PAS science projects will be included.


title: A magic square from Yang-Mills squared

abstract:
  We give a unified description of D = 3 super-Yang-Mills theory with N = 1, 2,
4, and 8 supersymmeties in terms of the four division algebras: reals (R),
complexes (C), quaternions (H) and octonions (O). Tensoring left and right
super-Yang-Mills multiplets with N = 1, 2, 4, 8 we obtain a magic square RR,
CR, CC, HR, HC, HH, OR, OC, OH, OO description of D = 3 supergravity with N =
2, 3, 4, 5, 6, 8, 9, 10, 12, 16.


title: Network Throughput Optimization via Error Correcting Codes

abstract:
  A new network construction method is presented for building of scalable, high
throughput, low latency networks. The method is based on the exact equivalence
discovered between the problem of maximizing network throughput (measured as
bisection bandwidth) for a large class of practically interesting Cayley graphs
and the problem of maximizing codeword distance for linear error correcting
codes. Since the latter problem belongs to a more mature research field with
large collections of optimal solutions available, a simple translation recipe
is provided for converting the existent optimal error correcting codes into
optimal throughput networks. The resulting networks, called here Long Hop
networks, require 1.5-5 times fewer switches, 2-6 times fewer internal cables
and 1.2-2 times fewer `average hops' than the best presently known networks for
the same number of ports provided and the same total throughput. These
advantage ratios increase with the network size and switch radix. Independently
interesting byproduct of the discovered equivalence is an efficient O(n*log(n))
algorithm based on Walsh-Hadamard transform for computing exact bisections of
this class of Cayley graphs (this is NP complete problem for general graphs).


title: Motion of macroscopic bodies in the electromagnetic field

abstract:
  A theory is presented for calculating the effect of the electromagnetic field
on the centre of mass of a macroscopic dielectric body that is valid in both
quantum and classical regimes. We apply the theory to find the classical
equation of motion for the centre of mass of a macroscopic object in a
classical field, and the spreading of an initially localized wave-packet
representing the centre of mass of a small object, in a quantum field. The
classical force is found to be consistent with the identification of the
Abraham momentum with the mechanical momentum of light, and the motion of the
wave-packet is found to be subject to an acceleration due to the Casimir force,
and a time dependent fluctuating motion due the creation of pairs of
excitations within the object. The theory is valid for any dielectric that has
susceptibilities satisfying the Kramers-Kronig relations, and is not subject
to arguments regarding the form of the electromagnetic energy-momentum tensor
within a medium.


title:
Active Galactic Nuclei - the Physics of Individual Sources and the
  Cosmic History of Formation and Evolution

abstract:
  In this paper we give a brief review of the astrophysics of active galactic
nuclei (AGN). After a general introduction motivating the study of AGNs, we
discuss our present understanding of the inner workings of the central engines,
most likely accreting black holes with masses between a million and ten billion
solar masses. We highlight recent results concerning the jets (collimated
outflows) of AGNs derived from X-ray observations (Chandra) of kpc-scale jets
and gamma-ray observations of AGNs (Fermi, Cherenkov telescopes) with jets
closely aligned with the lines of sight (blazars), and discuss the
interpretation of these observations. Subsequently, we summarize our knowledge
about the cosmic history of AGN formation and evolution. We conclude with a
description of upcoming observational opportunities.


title: Temporal Decomposition Studies of GRB Lightcurves

abstract:
  Gamma-ray bursts (GRB) are extremely energetic events and produce highly
diverse light curves. Light curves are believed to be resulting from internal
shocks reflecting the activities of the GRB central engine. Hence their
temporal studies can potentially lead to the understanding of the GRB central
engine and its evolution. The light curve variability time scale is an
interesting parameter which most models attribute to a physical origin e.g.,
central engine activity, clumpy circumburst medium, or relativistic turbulence.
We develop a statistical method to estimate the GRB minimum variability time
scale (MVT) for long and short GRBs detected by GBM. We find that the MVT of
short bursts is distinctly shorter than that for long GRBs supprting the
possibility of a more compact central engine of the former. We find that MVT
estimated by this method is consistent with the shortest rise time of the
fitted pulses. Hence we use the fitted pulse rise times to study the evolution
of burst variability time scale. Variability time is in turn related to the
minimum bulk Lorentz factor. Using this we relate the GRB spectral evolution to
the evolution of the variability time scale. %Gamma-ray burst (GRB) light
curves are believed to result from internal shocks reflecting the activities of
the GRB central engine. %Hence their temporal deconvolution studies can
potentially lead to the understanding of the evolution of the minimum
variability %time scales which in turn is related to the minimum bulk Lorentz
factor. We relate the GRB spectral evolution to the evolution of the %minimum
variability time scale.


title: Gravitational- and Self- Coupling of Partially Massless Spin 2

abstract:
  We show that higher spin systems specific to cosmological spaces are subject
to the same problems as models with Poincar'e limits. In particular, we analyse
partially massless (PM) spin 2 and find that both its gravitational coupling
and nonlinear extensions suffer from the usual [background- and self-coupling]
difficulties: Consistent free field propagation does not extend beyond
background Einstein geometries. Then, using conformal Weyl gravity (CG), which
consists of relative ghost PM and graviton excitations, we find that avoiding
graviton-ghosts restricts CG-generated PM self-couplings to the usual, safe,
Noether current cubic ones.


title:
Current noise and higher order fluctuations in semiconducting bilayer
  systems

abstract:
  We analyze the transport properties of a semiconductor based bilayer system
under non-equilibrium conditions with special emphasis on the charge transfer
statistics in the regime dominated by the exciton transport. We consider two
different models. In one of them the transport occurs incoherently and is
dominated by incoherent tunneling processes of individual excitons, while in
the other system no disorder is present and transport processes are fully
coherent. We find that the strength of cross correlations of currents in
different layers is only insignificantly affected by the disorder and shows up
similar behaviour in both systems. We discuss possible experimental
realizations and make predictions for measurable quantities.


title: On Graphical Models via Univariate Exponential Family Distributions

abstract:
  Undirected graphical models, or Markov networks, are a popular class of
statistical models, used in a wide variety of applications. Popular instances
of this class include Gaussian graphical models and Ising models. In many
settings, however, it might not be clear which subclass of graphical models to
use, particularly for non-Gaussian and non-categorical data. In this paper, we
consider a general sub-class of graphical models where the node-wise
conditional distributions arise from exponential families. This allows us to
derive multivariate graphical model distributions from univariate exponential
family distributions, such as the Poisson, negative binomial, and exponential
distributions. Our key contributions include a class of M-estimators to fit
these graphical model distributions; and rigorous statistical analysis showing
that these M-estimators recover the true graphical model structure exactly,
with high probability. We provide examples of genomic and proteomic networks
learned via instances of our class of graphical models derived from Poisson and
exponential distributions.


title:
Improving the Spectral Efficiency of Nonlinear Satellite Systems through
  Time-Frequency Packing and Advanced Processing

abstract:
  We consider realistic satellite communications systems for broadband and
broadcasting applications, based on frequency-division-multiplexed linear
modulations, where spectral efficiency is one of the main figures of merit. For
these systems, we investigate their ultimate performance limits by using a
framework to compute the spectral efficiency when suboptimal receivers are
adopted and evaluating the performance improvements that can be obtained
through the adoption of the time-frequency packing technique. Our analysis
reveals that introducing controlled interference can significantly increase the
efficiency of these systems. Moreover, if a receiver which is able to account
for the interference and the nonlinear impairments is adopted, rather than a
classical predistorter at the transmitter coupled with a simpler receiver, the
benefits in terms of spectral efficiency can be even larger. Finally, we
consider practical coded schemes and show the potential advantages of the
optimized signaling formats when combined with iterative detection/decoding.


title: A new entropy power inequality for integer-valued random variables

abstract:
  The entropy power inequality (EPI) provides lower bounds on the differential
entropy of the sum of two independent real-valued random variables in terms of
the individual entropies. Versions of the EPI for discrete random variables
have been obtained for special families of distributions with the differential
entropy replaced by the discrete entropy, but no universal inequality is known
(beyond trivial ones). More recently, the sumset theory for the entropy
function provides a sharp inequality $H(X+X')-H(X)\geq 1/2 -o(1)$ when $X,X'$
are i.i.d. with high entropy. This paper provides the inequality $H(X+X')-H(X)
\geq g(H(X))$, where $X,X'$ are arbitrary i.i.d. integer-valued random
variables and where $g$ is a universal strictly positive function on $\mR_+$
satisfying $g(0)=0$. Extensions to non identically distributed random variables
and to conditional entropies are also obtained.


title:
Dark Matter Mass Constrained by the Relic Abundance, Direct Detections,
  and Colliders

abstract:
  We take into account a generic form of a Dirac fermionic dark matter (DM),
which communicates with the Standard Model quarks via a scalar mediator, in a
model-independent way. Four special interaction scenarios are investigated,
where one is parity conserving and the other three are parity violating. Three
of them result in the $v$ suppressed DM-nucleon cross sections, where $v \sim
10^{-3} c$ is the velocity of the DM in the laboratory frame. We constrain the
masses of the dark matter and mediator as well as the couplings from the
thermal relic abundance, and the recent results of the XENON100 direct
detection and collider experiments involving the two channels: (i) monojet plus
large missing transverse energy, and (ii) dijet. The current monojet constraint
is not stronger than that from the requirement of the correct relic density and
the null result by the XENON100 direct detection. We find that the dijet
resonance measurements can exclude a large part of the parameter space
$(m_\chi, m_Y)$, where the couplings for the mediator coupled to the dark
matter and to the quarks are small and have roughly the same magnitude. The
constraint from indirect detections and diphoton resonance searches is also
briefly discussed.

categories: hep-ph astro-ph.CO astro-ph.GA astro-ph.HE hep-ex


title:
Dynamical localization in chaotic systems: spectral statistics and
  localization measure in the kicked rotator as a paradigm for time-dependent
  and time-independent systems

abstract:
  We study quantum kicked rotator in the classically fully chaotic regime, in
the domain of the semiclassical behaviour. We use Izrailev's N-dimensional
model for various N<=4000, which in the limit N-> infinity tends to the
quantized kicked rotator, not only for K=5 as studied previously, but for many
different values of the classical kick parameter 5<=K<=35, and also of the
quantum parameter k. We describe the dynamical localization of chaotic
eigenstates as a paradigm for other both time-periodic and time-independent
fully chaotic or/and mixed type Hamilton systems. We generalize the
localization length L and the scaling variable (L/N) to the case of anomalous
classical diffusion. We study the generalized classical diffusion also in the
regime where the simple minded theory of the normal diffusion fails. We greatly
improve the accuracy of the numerical calculations with the following
conclusions: The level spacings distribution of the eigenphases is very well
described by the Brody distribution, systematically better than by other
proposals, for various Brody exponents. When N->infinity and L is fixed we have
always Poisson, even in fully chaotic regime. We study the eigenfunctions of
the Floquet operator and characterize their localization properties using the
information entropy measure describing the degree of dynamical localization of
the eigenfunction. The resulting localization parameter is found to be almost
equal to the Brody parameter. We show the existence of a scaling law between
the localization parameter and the scaling variable L/N, now including the
regimes of anomalous diffusion. The above findings are important also in
time-independent Hamilton systems, like in mixed type billiards, where the
Brody distribution is confirmed to a very high degree of precision for
dynamically localized chaotic eigenstates.


title: Optimal synchronizability of bearings

abstract:
  Bearings are mechanical dissipative systems that, when perturbed, relax
toward a synchronized (bearing) state. Here we find that bearings can be
perceived as physical realizations of complex networks of oscillators with
asymmetrically weighted couplings. Accordingly, these networks can exhibit
optimal synchronization properties through fine tuning of the local interaction
strength as a function of node degree [Motter, Zhou, and Kurths, Phys. Rev. E
71, 016116 (2005)]. We show that, in analogy, the synchronizability of bearings
can be maximized by counterbalancing the number of contacts and the inertia of
their constituting rotor disks through the mass-radius relation, $m\sim
r^{\alpha}$, with an optimal exponent $\alpha=\alpha_{\times}$ which converges
to unity for a large number of rotors. Under this condition, and regardless of
the presence of a long-tailed distribution of disk radii composing the
mechanical system, the average participation per disk is maximized and the
energy dissipation rate is homogeneously distributed among elementary rotors.


title:
Explaining the Dark Energy, Baryon and Dark Matter Coincidence via
  Domain-Dependent Random Densities

abstract:
  The dark energy, dark matter and baryon densities in the Universe are
observed to be similar, with a factor of no more than 20 between the largest
and smallest densities. We show that this coincidence can be understood via
superhorizon domains of randomly varying densities when the baryon density at
initial collapse of galaxy-forming perturbations is determined by anthropic
selection. The baryon and dark matter densities are assumed to be dependent on
random variables \theta_{d} and \theta_{b} according to \rho_{dm} ~
\theta_{d}^{\alpha} and \rho_{b} ~ \theta_{b}^{\beta}, while the effectively
constant dark energy density is dependent upon a random variable \phi_{Q}
according to \rho_{Q} ~ \phi_{Q}^{n}. The ratio of the baryon density to the
dark energy density at initial collapse, r_{Q}, and the baryon-to-dark matter
ratio, r, are then determined purely statistically, with no dependence on the
anthropically-preferred baryon density. We compute the probability distribution
for r_{Q} and r and show that the observed values of r_{Q} and r can be
naturally understood within this framework. In particular, for the case \alpha
= 2, \beta = 1 and n = 4, which can be physically realized via a combination of
axion dark matter, Affleck-Dine baryogenesis and frozen quintessence with a
\phi_{Q}^4 potential, the range of r_{Q} and r which corresponds to the
observed Universe is a quite natural, with a probability which is broadly
similar to other ranges of r_{Q} and r.


title: Phyllotaxis, Pushed Pattern-Forming Fronts and Optimal Packing

abstract:
  We demonstrate that the pattern forming partial differential equation derived
from the auxin distribution model proposed by Meyerowitz, Traas and others
gives rise to all spiral phyllotaxis properties observed on plants. We show how
the advancing pushed pattern front chooses spiral families enumerated by
Fibonacci sequences with all attendant self similar properties and connect the
results with the optimal packing based algorithms previously used to explain
phyllotaxis. Our results allow us to make experimentally testable predictions.


title: A bootstrap strategy for asymptotic safety

abstract:
  A search strategy for asymptotic safety is put forward and tested for a
simplified version of gravity in four dimensions using the renormalization
group. Taking the action to be a high-order polynomial of the Ricci scalar, a
self-consistent ultraviolet fixed point is found where curvature invariants
become increasingly irrelevant with increasing mass dimension. Intriguingly,
universal scaling exponents take near-Gaussian values despite the presence of
residual interactions. Asymptotic safety of metric gravity would seem in reach
if this pattern carries over to the full theory.


title: On the formation of structure in growing networks

abstract:
  Based on the formation of triad junctions, the proposed mechanism generates
networks that exhibit extended rather than single power law behavior. Triad
formation guarantees strong neighborhood clustering and community-level
characteristics as the network size grows to infinity. The asymptotic behavior
is of interest in the study of directed networks in which (i) the formation of
links cannot be described according to the principle of preferential
attachment; (ii) the in-degree distribution fits a power law for nodes with a
high degree and an exponential form otherwise; (iii) clustering properties
emerge at multiple scales and depend on both the number of links that newly
added nodes establish and the probability of forming triads; and (iv) groups of
nodes form modules that feature less links to the rest of the nodes.


title:
A Markov chain model of evolution in asexually reproducing populations:
  insight and analytical tractability in the evolutionary process

abstract:
  The evolutionary process has been modelled in many ways using both stochastic
and deterministic models. We develop an algebraic model of evolution in a
population of asexually reproducing organisms in which we represent a
stochastic walk in phenotype space, constrained to the edges of an underlying
graph representing the genotype, with a time-homogeneous Markov Chain. We show
its equivalence to a more standard, explicit stochastic model and show the
algebraic model's superiority in computational efficiency. Because of this
increase in efficiency, we offer the ability to simulate the evolution of much
larger populations in more realistic genotype spaces. Further, we show how the
algebraic properties of the Markov Chain model can give insight into the
evolutionary process and allow for analysis using familiar linear algebraic
methods.


title:
Financial Portfolio Optimization: Computationally guided agents to
  investigate, analyse and invest!?

abstract:
  Financial portfolio optimization is a widely studied problem in mathematics,
statistics, financial and computational literature. It adheres to determining
an optimal combination of weights associated with financial assets held in a
portfolio. In practice, it faces challenges by virtue of varying math.
formulations, parameters, business constraints and complex financial
instruments. Empirical nature of data is no longer one-sided; thereby
reflecting upside and downside trends with repeated yet unidentifiable cyclic
behaviours potentially caused due to high frequency volatile movements in asset
trades. Portfolio optimization under such circumstances is theoretically and
computationally challenging. This work presents a novel mechanism to reach an
optimal solution by encoding a variety of optimal solutions in a solution bank
to guide the search process for the global investment objective formulation. It
conceptualizes the role of individual solver agents that contribute optimal
solutions to a bank of solutions, a super-agent solver that learns from the
solution bank, and, thus reflects a knowledge-based computationally guided
agents approach to investigate, analyse and reach to optimal solution for
informed investment decisions.
  Conceptual understanding of classes of solver agents that represent varying
problem formulations and, mathematically oriented deterministic solvers along
with stochastic-search driven evolutionary and swarm-intelligence based
techniques for optimal weights are discussed. Algorithmic implementation is
presented by an enhanced neighbourhood generation mechanism in Simulated
Annealing algorithm. A framework for inclusion of heuristic knowledge and human
expertise from financial literature related to investment decision making
process is reflected via introduction of controlled perturbation strategies
using a decision matrix for neighbourhood generation.


title:
A hybrid OpenMP and MPI implementation of a conservative spectral method
  for the Boltzmann equation

abstract:
  We demonstrate the implementation of a hybrid OpenMP and MPI parallelization
of a conservative spectral method for the Boltzmann equation originally
developed by Gamba and Tharkabhushaman. We perform a scaling analysis to
demonstrate that the problem is well suited to parallelization, and find that
the computational time scales linearly with the number of compute nodes on high
performance computing resources. The original method has also been improved to
higher order in space and time and is implemented on non-uniform grids in
physical space. We test this scheme for an example problem in which a kinetic
boundary layer generates a shock wave for large space and long times. This is
the first time that the fully nonlinear Boltzmann collision operator has been
used to compute this problem.


title: Embedding Theorems for the Dunkl Harmonic Oscillator on the Line

abstract:
  Embedding results of Sobolev type are proved for the Dunkl harmonic
oscillator on the line.


title: Negative Baryon density and the Folding structure of the B=3 Skyrmion

abstract:
  The Skyrme model is a non-linear field theory whose solitonic solutions, once
quantised, describe atomic nuclei. The classical static soliton solutions,
so-called Skyrmions, have interesting discrete symmetries and can only be
calculated numerically. Mathematically, these Skyrmions can be viewed as maps
between to two three-manifolds and, as such, their stable singularities can
only be folds, cusps and swallowtails. Physically, the occurrence of
singularities is related to negative baryon density. In this paper, we
calculate the charge three Skyrmion to a high resolution in order to examine
its singularity structure in detail. Thereby, we explore regions of negative
baryon density. We also discuss how the negative baryon density depends on the
pion mass.


title: Schwarzschild Solution in R-spacetime

abstract:
  Here we construct new solution for the Einstein equations -- some analog of
the Schwarzschild metric in anti--de Sitter--Beltrami space in the $c\to
\infty$ limit ($R$-space). In this case we derive an adiabatic invariant for
finite movement of the massive point particle and separate variables
Hamilton--Jacobi equation. Quasi orbital motion is analyzed and its radius time
dependence is obtained.


title:
Multichannel generalization of eigen-phase preserving supersymmetric
  transformations

abstract:
  We generalize eigen-phase preserving (EPP) supersymmetric (SUSY)
transformations to $N>2$ channel Schr\"odinger equation with equal thresholds.
It is established that EPP SUSY transformations exist only in the case of even
number of channels, $N=2M$. A single EPP SUSY transformation provides an
$M(M-1)+2$ parametric deformation of the matrix Hamiltonian without affecting
eigen-phase shifts of the scattering matrix.


title:
Enabling Operator Reordering in Data Flow Programs Through Static Code
  Analysis

abstract:
  In many massively parallel data management platforms, programs are
represented as small imperative pieces of code connected in a data flow. This
popular abstraction makes it hard to apply algebraic reordering techniques
employed by relational DBMSs and other systems that use an algebraic
programming abstraction. We present a code analysis technique based on reverse
data and control flow analysis that discovers a set of properties from user
code, which can be used to emulate algebraic optimizations in this setting.


title:
Chemical enrichment of Damped Lyman Alpha systems as a direct constraint
  on Population III star formation

abstract:
  Damped Ly-alpha absorbers (DLAs) can be used to measure gas-phase
metallicities at large cosmological lookback times with high precision.
Relative abundances can still be measured accurately deep into the reionization
epoch (z > 6) using transitions redward of Ly-alpha. Here we study chemical
evolution of DLAs using a constrained model for evolution of galaxies and IGM
to determine the degree to which DLA abundance measurements can probe
Population III enrichment. We find that if the critical metallicity of
Population III to II transition is < 10^-4 Zsun, the cosmic Population III SFR
is zero for z<8. Nevertheless, at high redshift (z ~ 6) Population III chemical
signatures are retained in low-mass galaxies (halo mass < 10^9 Msun). This is
because photoionization feedback suppresses star formation in these galaxies
until relatively low redshift (z ~ 10), and the chemical record of early
Population III star formation is retained. We model DLAs as these galaxies by
assigning to them a mass-dependent H I absorption cross section and predict
distribution of DLA abundance ratios. We find that these distributions are
anchored towards abundance ratios set by Population II yields, but exhibit a
tail that depends on the Population III IMF for z > 5. Thus, a sample of DLA
abundance measurements at high redshift holds the promise to constrain
Population III IMF. A sample of just 10 DLAs with relative abundances measured
to an accuracy of 0.1 dex is sufficient to constrain the Population III IMF at
4-sigma. These constraints may prove stronger than other probes such as
metal-poor stars and individual DLAs. Our results provide a global picture of
the cosmic thermal, ionization, and chemical evolution, and can rule out
certain Population III scenarios.


title:
A general inversion formula for summatory arithmetic functions and its
  application to the summatory function of the Moebius function

abstract:
  We prove an inversion formula for summatory arithmetic functions. As an
application, we obtain an arithmetic relationship between summatory Piltz
divisor functions and a sum of the M\"obius function over certain integers,
denoted by $M(x,y)$. With this relationship, using bounds for the main and
remainder terms in the $k$-divisor problems we deduce conditional and
unconditional results concerning $M(x,y)$ and the zero-free region of the
Riemann zeta-function and Dirichlet $L$-functions.


title: Nuclear matrix elements for double-{\beta} decay

abstract:
  Background: Direct determination of the neutrino mass through double-$\beta$
decay is at the present time one of the most important areas of experimental
and theoretical research in nuclear and particle physics. Purpose: We calculate
nuclear matrix elements for the extraction of the average neutrino mass in
neutrinoless double-$\beta$ decay. Methods: The microscopic interacting boson
model (IBM-2) is used. Results: Nuclear matrix elements in the closure
approximation are calculated for $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr,
$^{100}$Mo, $^{110}$Pd, $^{116}$Cd, $^{124}$Sn, $^{128}$Te, $^{130}$Te,
$^{148}$Nd, $^{150}$Nd, $^{154}$Sm, $^{160}$Gd, and $^{198}$Pt decay.
Conclusions: Realistic predictions for the expected half-lives in neutrinoless
double-$\beta$ decay with light and heavy neutrino exchange in terms of
neutrino masses are made and limits are set from current experiments.


title:
DSAT-MAC : Dynamic Slot Allocation based TDMA MAC protocol for Cognitive
  Radio Networks

abstract:
  Cognitive Radio Networks (CRN) have enabled us to efficiently reuse the
underutilized radio spectrum. The MAC protocol in CRN defines the spectrum
usage by sharing the channels efficiently among users. In this paper we propose
a novel TDMA based MAC protocol with dynamically allocated slots. Most of the
MAC protocols proposed in the literature employ Common Control Channel (CCC) to
manage the resources among Cognitive Radio (CR) users. Control channel
saturation in case of large number of CR users is one of the main drawbacks of
the CCC based MAC protocols. In contrast with CCC based MAC protocols, DSAT-MAC
protocol is based on the TDMA mechanism, without using any CCC for control
information exchange. The channels are divided into time slots and CR users
send their control or data packets over their designated slot. The protocol
ensures that no slot is left vacant. This guarantees full use of the available
spectrum. The protocol includes the provision for Quality of Service, where
real-time and safety critical data is transmitted with highest priority and
least delay. The protocol also ensures a fair sharing of available spectrum
among the CR users, with the mechanism to regulate the transmission of
malicious nodes. Energy saving techniques are also presented for longer life of
battery operated CR nodes. Theoretical analysis and simulations over ns-2 of
the proposed protocol reveal that the protocol performs better in various CR
adhoc network applications.


title: Valley Chern Numbers and Boundary Modes in Gapped Bilayer Graphene

abstract:
  Electronic states at domain walls in bilayer graphene are studied by
analyzing their four and two band continuum models, by performing numerical
calculations on the lattice, and by using quantum geometric arguments. The
continuum theories explain the distinct electronic properties of boundary modes
localized near domain walls formed by interlayer electric field reversal, by
interlayer stacking reversal, and by simultaneous reversal of both quantities.
Boundary mode properties are related to topological transitions and gap
closures which occur in the bulk Hamiltonian parameter space. The important
role played by intervalley coupling effects not directly captured by the
continuum model is addressed using lattice calculations for specific domain
wall structures.


title:
Structure of the Group of Balanced Labelings on Graphs, its Subgroups
  and Quotient Groups

abstract:
  We discuss functions from edges and vertices of an undirected graph to an
Abelian group. Such functions, when the sum of their values along any cycle is
zero, are called balanced labelings. The set of balanced labelings forms an
Abelian group. We study the structure of this group and the structure of two
closely related to it groups: the subgroup of balanced labelings which consists
of functions vanishing on vertices and the corresponding factor-group. This
work is completely self-contained, except the algorithm for obtaining the
3-edge-connected components of an undirected graph, for which we make
appropriate references to the literature.


title:
Anticipatory Systems, Preferences, Averages: Inflation, Uncertain
  Phenomena, Management

abstract:
  Behavior of systems that are functions of anticipated behavior of other
systems, whose own behavior is also anticipatory but homeostatic and determined
by hierarchical ordering, which changes over time, of sets of possible
environments that are not co-possible, is proven to be highly non-linear and
sensitively dependent on precise parameters. Averages and other kinds of
aggregates cannot be calculated for sets of measurements of behavior of
systems, defined in this essay, that are "index complex" in this way. This
includes many systems, for instance, social behavior, where anticipation of
behavior of other individuals plays a central role. Anticipation of preferences
of economic actors are discussed in this way. Analysis by way of generalized
functions of complex variables is done for these kinds of systems, and
equations of change of state are formally described. Behavior that comprises of
responses to market interest rates is taken for example. Continuity assumptions
in economics analyzed in this context. Anticipatory responses to inflation in
economics are discussed. Applications to theory of production are presented.


title:
Characteristics of plasmonic at a metal /chiral sculptured thin film
  interface

abstract:
  The propagation of surface plasmon polariton at an interface of metallic thin
film and chiral sculptured thin film theoretically has been investigated using
the transfer matrix method in the Kretschman configuration. The optical
absorption of structure as a function of polar incident angle for linear
polarization P and S has been calculated at different structural parameters.
The results show that exist multiple plasmon peaks for P-polarization, while
there are the weak plasmon peaks when incident of light is S- polarized plane
wave.


title:
A note on configurations in sets of positive density which occur at all
  large scales

abstract:
  Furstenberg, Katznelson and Weiss proved in the early 1980s that every
measurable subset of the plane with positive density at infinity has the
property that all sufficiently large real numbers are realised as the Euclidean
distance between points in that set. Their proof used ergodic theory to study
translations on a space of Lipschitz functions corresponding to closed subsets
of the plane, combined with a measure-theoretical argument. We consider an
alternative dynamical approach in which the phase space is given by the set of
measurable functions from $\mathbb{R}^d$ to $[0,1]$, which we view as a compact
subspace of $L^\infty(\mathbb{R}^d)$ in the weak-* topology. The pointwise
ergodic theorem for $\mathbb{R}^d$-actions implies that with respect to any
translation-invariant measure on this space, almost every function is
asymptotically close to a constant function at large scales. This observation
leads to a general sufficient condition for a configuration to occur in every
set of positive upper Banach density at all sufficiently large scales,
extending a recent theorem of B. Bukh. To illustrate the use of this criterion
we apply it to prove a new result concerning three-point configurations in
measurable subsets of the plane which form the vertices of a triangle with
specified area and side length, yielding a new proof of a result related to
work of R. Graham.


title: Bivariant Algebraic Cobordism

abstract:
  We associate a bivariant theory to any suitable oriented Borel-Moore homology
theory on the category of algebraic schemes or the category of algebraic
G-schemes. Applying this to the theory of algebraic cobordism yields
operational cobordism rings and operational G-equivariant cobordism rings
associated to all schemes in these categories. In the case of toric varieties,
the operational T-equivariant cobordism ring may be described as the ring of
piecewise graded power series on the fan with coefficients in the Lazard ring.


title: Information-related complexity: a problem-oriented approach

abstract:
  A general notion of information-related complexity applicable to both natural
and man-made systems is proposed. The overall approach is to explicitly
consider a rational agent performing a certain task with a quantifiable degree
of success. The complexity is defined as the minimum (quasi-)quantity of
information that's necessary to complete the task to the given extent --
measured by the corresponding loss. The complexity so defined is shown to
generalize the existing notion of statistical complexity when the system in
question can be described by a discrete-time stochastic process. The proposed
definition also applies, in particular, to optimization and decision making
problems under uncertainty in which case it gives the agent a useful measure of
the problem's "susceptibility" to additional information and allows for an
estimation of the potential value of the latter.


title: Non-Markovian Toy Quantum Chain

abstract:
  We propose a simple structure for stationary non-Markovian quantum chains in
the framework of collisional dynamics of open quantum systems. To this end, we
modify the microscopic Markovian system--reservoir model, consider multiple
collisions with each of the molecules with an overlap between the collisional
time intervals. We show how the equivalent Markovian quantum chain can be
constructed with the addition of satellite quantum memory to the system. We
distinguish quantum from classical non-Markovianity. Moreover, we define the
counts of non-Markovianity by the required number of satellite qubits and bits,
respectively. As the particular measure of quantum non-Markovianity the discord
of the satellite w.r.t. the system is suggested. Simplest qubit realizations
are discussed, and the significance for real system--environment dynamics is
also pointed out.


title:
Surface plasmon resonance of two segmented Au Cu nanowires in
  polycarbonate template

abstract:
  Two segmented gold copper nanowires were grown inside the pores of
polycarbonate track (PCT) etched membranes from two separate solutions by
electrodeposition method. Optical absorption spectra of two segmented Au Cu
nanowires in PCT template were shown a surface plasmon- polariton peak appeared
at about 900 nm for incident angle of theta = 65 degrees but for theta= 0 there
are not any peaks in spectra.


title: Probing new physics with tau-leptons at the LHC

abstract:
  We discuss new physics that can show up in the $\tau^+\tau^-$ production
process at the LHC but not in the dimuon or the dielectron channels. We
consider three different generic possibilities: a new resonance in the
Drell-Yan process in the form of a non-universal $Z^\prime$; a new non-resonant
contribution to $q\bar{q}\to \tau^+\tau^-$ in the form of leptoquarks; and
contributions from gluon fusion due to effective lepton gluonic couplings. We
emphasize the use of the charge asymmetry both to discover new physics and to
distinguish between different possibilities


title: Forces on Solitons in Finite, Nonlinear, Planar Waveguides

abstract:
  The forces acting on and the energies of solitons governed by the nonlinear
Schr\"odinger equation in finite, planar waveguides with periodic and with
homogeneous Dirichlet, Neumann and Robin boundary conditions are determined by
means of a quantum analogy. It is shown that these densities have S-shape
profiles and increase as the hardness of the boundary conditions is increased.


title:
Synthesis of Nanoparticles of the Giant Dielectric Material, CaCu3Ti4O12
  from a Precursor Route

abstract:
  A complex oxalate precursor, CaCu3(TiO)4(C2O4)8.9H2O, was synthesized and the
precipitate that obtained was confirmed to be monophasic by the wet chemical
analyses, X-ray diffraction, FTIR absorption and TG, DTA analyses. The thermal
decomposition of this oxalate precursor led to the formation of phase-pure
calcium copper titanate, CaCu3Ti4O12, at 680oC. The bright field TEM
micrographs revealed that the size of the as synthesized crystallites to be in
the 30 to 80 nm range. The powders so obtained had excellent sinterability
resulting in high density ceramics which exhibited giant dielectric constants
upto 40000 (1 kHz) at 25oC accompanied by low dielectric losses, less than
0.07.


title: BTZ black holes inspired by noncommutative geometry

abstract:
  In this paper a Banados, Teitelboim and Zanelli (BTZ) black hole is
constructed from an exact solution of the Einstein field equations in a
(2+1)-dimensional anti-de Sitter spacetime in the context of noncommutative
geometry. The BTZ black hole turns out to have two horizons, no horizon or a
single horizon corresponding to a minimal mass. Certain thermodynamical
properties are investigated, including Hawking temperature, entropy and heat
capacity. Also discussed is the geodesic structure of BTZ black holes for both
massless and massive particles. In particular, it is shown that bound orbits
for test particles are possible.


title:
Structural, Thermal and Electrical properties of Poly(methyl
  methacrylate)-CaCu3Ti4O12 composite sheets fabricated via melt mixing

abstract:
  Poly(Methyl Methacrylate) (PMMA) and CaCu3Ti4O12 (CCTO) composites were
fabricated via melt mixing followed by hot pressing technique. These were
characterized using X-ray diffraction (XRD), thermo gravimetric (TGA), Thermo
Mechanical (TMA), Differential scanning calorimetry (DSC), Fourier transform
infrared (FTIR), and Impedance analyser for their structural, thermal and
dielectric properties. Composites were found to have better thermal stability
than that of pure PMMA. However, there was no significant difference in the
glass transition (Tg) temperature between the polymer and the composite. The
appearance of additional vibrational frequencies in the range 400-600 cm-1 in
FTIR spectra indicated a possible interaction between PMMA and CCTO. The
composite, with 38 Vol % of CCTO (in PMMA), exhibited remarkably low dielectric
loss at high frequencies and the low frequency relaxation is attributed to the
space charge polarization/MWS effect. The origin of AC conductivity
particularly in the high frequency region was attributed to the electronic
polarization.


title: Interactions and Focusing of Nonlinear Water Waves

abstract:
  The coupled cubic nonlinear Schr\"odinger (CNLS) equations are used to study
modulational instabilities of a pair of nonlinearly interacting two-dimensional
waves in deep water. It has been shown that the full dynamics of these
interacting waves gives rise to localized large-amplitude wavepackets (wave
focusing). In this short letter we attempt to verify this result numerically
using a Fourier spectral method for the CNLS equations.


title:
A Research Note on the Implementation of Star Formation and Stellar
  Feedback in Semi-Analytic Models

abstract:
  We study the impact of star formation and stellar feedback prescriptions on
galaxy properties predicted by means of "stripped-down" versions of
independently developed semi-analytic models (SAMs). These include cooling,
star formation, feedback from supernovae (SNe) and simplified prescriptions for
galaxy merging, but no chemical evolution, disc instabilities or AGN feedback.
We run these versions on identical samples of dark matter (DM) haloes extracted
from high-resolution N-body simulations in order to perform both statistical
analysis and object-by-object comparisons. We compare our results with previous
work based on stripped-down versions of the same SAMs including only gas
cooling, and show that all feedback models provide coherent modifications in
the distribution of baryons between the various gas phases. In particular, we
find that the predicted hot gas fractions are considerably increased by up to a
factor of three, while the corresponding cold gas fractions are correspondingly
decreased, and a significant amount of mass is ejected from the DM halo.
Nonetheless, we also find relevant differences in the predicted properties of
model galaxies among the three SAMs: these deviations are more relevant at mass
scales comparable to that of our own Galaxy, and are reduced at larger masses,
confirming the varying impact of stellar feedback at different mass scales. We
also check the effect of enhanced star formation events (i.e. starbursts
modes), defined in connection with galaxy mergers. We find that, in general,
these episodes have a limited impact in the overall star formation histories of
model galaxies, even in massive DM halos where merger-driven star formation has
often been considered very important.


title: Neutrino Mass from a d=7 Effective Operator in a SUSY-GUT Framework

abstract:
  Models, where neutrino mass originates from physics at the TeV scale and
which are potentially testable at the LHC, need additional suppression
mechanisms to describe the smallness of neutrino masses. We consider models in
which neutrino mass is generated from the d=7 operator $L L H_u H_u H_d H_u$ in
the context of SUSY-GUTs containing an SU(5) subgroup, here the d=5 Weinberg
operator can be forbidden by a discrete symmetry. That is, we identify the
embeddings in GUT multiplets and their consequences for phenomenology and
renormalization group evolution. We use a specific example to exemplify the
challenges. In this case, additional heavy d-quarks are predicted, which are
constrained by cosmology, in particular, by big bang nucleosynthesis and direct
searches for heavy nuclei. We show that in the NMSSM extension of the model,
the discrete symmetry needs to be broken, which can be the origin of deviations
from tri-bimaximal mixings. Finally we demonstrate that our example is the only
tree level decomposition which is consistent with perturbativity up to the GUT
scale and neutrino mass generation by a leading d=7 contribution.


title: Dimer Mott Insulator in an Oxide Heterostructure

abstract:
  We study the problem of designing an artificial Mott insulator in a
correlated oxide heterostructure. We consider the extreme limit of quantum
confinement based on ionic discontinuity doping, and argue that a unique dimer
Mott insulator can be achieved for the case of a single SrO layer in a
GdTiO$_3$ matrix. In the dimer Mott insulator, electrons are localized not to
individual atoms but to bonding orbitals on molecular dimers formed across a
bilayer of two TiO$_2$ planes, and is analogous to the Mott insulating state of
Hubbard ladders, studied in the 1990s. We verify the existence of the dimer
Mott insulator through both ab initio and model Hamiltonian studies, and find
for reasonable values of Hubbard $U$ that it is stable and ferromagnetic with a
clear bonding/anti-bonding splitting of order 0.65eV, and a significant smaller
Mott gap whose size depends upon $U$. The combined effects of polar
discontinuity, strong structural relaxation and electron correlations all
contribute to the realization of this unique ground state.


title: Excitation spectra of disordered dimer magnets near quantum criticality

abstract:
  For coupled-dimer magnets with quenched disorder, we introduce a
generalization of the bond-operator method, appropriate to describe both
singlet and magnetically ordered phases. This allows for a numerical
calculation of the magnetic excitations at all energies across the phase
diagram, including the strongly inhomogeneous Griffiths regime near quantum
criticality. We apply the method to the bilayer Heisenberg model with bond
randomness and characterize both the broadening of excitations and the transfer
of spectral weight induced by disorder. Inside the antiferromagnetic phase this
model features the remarkable combination of sharp magnetic Bragg peaks and
broad magnons, the latter arising from the tendency to localization of
low-energy excitations.


title: Emergence of the Electroweak Scale through the Higgs Portal

abstract:
  Having discovered a candidate for the final piece of the Standard Model, the
Higgs boson, the question remains why its vacuum expectation value and its mass
are so much smaller than the Planck scale (or any other high scale of new
physics). One elegant solution was provided by Coleman and Weinberg, where all
mass scales are generated from dimensionless coupling constants via dimensional
transmutation. However, the original Coleman-Weinberg scenario predicts a Higgs
mass which is too light; it is parametrically suppressed compared to the mass
of the vectors bosons, and hence is much lighter than the observed value. In
this paper we argue that a mass scale, generated via the Coleman-Weinberg
mechanism in a hidden sector and then transmitted to the Standard Model through
a Higgs portal, can naturally explain the smallness of the electroweak scale
compared to the UV cutoff scale, and at the same time be consistent with the
observed value. We analyse the phenomenology of such a model in the context of
present and future colliders and low energy measurements.


title:
Super-Eddington accreting massive black holes as long-lived cosmological
  standards

abstract:
  Super-Eddington accreting massive black holes (SEAMBHs) reach saturated
luminosities above a certain accretion rate due to photon trapping and
advection in slim accretion disks. We show that these SEAMBHs could provide a
new tool for estimating cosmological distances if they are properly identified
by hard X-ray observations, in particular by the slope of their 2-10 keV
continuum. To verify this idea we obtained black hole mass estimates and X-ray
data for a sample of 60 narrow line Seyfert 1 galaxies that we consider to be
the most promising SEAMBH candidates. We demonstrate that the distances derived
by the new method for the objects in the sample get closer to the standard
luminosity distances as the hard X-ray continuum gets steeper. The results
allow us to analyze the requirements for using the method in future samples of
active black holes and to demonstrate that the expected uncertainty, given
large enough samples, can make them into a useful, new cosmological ruler.

categories: astro-ph.CO astro-ph.GA astro-ph.HE gr-qc


title: Theory of interacting dislocations on cylinders

abstract:
  We study the mechanics and statistical physics of dislocations interacting on
cylinders, motivated by the elongation of rod-shaped bacterial cell walls and
cylindrical assemblies of colloidal particles subject to external stresses. The
interaction energy and forces between dislocations are solved analytically, and
analyzed asymptotically. The results of continuum elastic theory agree well
with numerical simulations on finite lattices even for relatively small
systems. Isolated dislocations on a cylinder act like grain boundaries. With
colloidal crystals in mind, we show that saddle points are created by a
Peach-Koehler force on the dislocations in the circumferential direction,
causing dislocation pairs to unbind. The thermal nucleation rate of dislocation
unbinding is calculated, for an arbitrary mobility tensor and external stress,
including the case of a twist-induced Peach-Koehler force along the cylinder
axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite
their vanishing Gaussian curvature.


title: Impact of metallicity on the evolution of young star clusters

abstract:
  We discuss the results of N-body simulations of intermediate-mass young star
clusters (SCs) with three different metallicities (Z=0.01, 0.1 and 1 Zsun),
including metallicity-dependent stellar evolution recipes and
metallicity-dependent prescriptions for stellar winds and remnant formation.
The initial half-mass relaxation time of the simulated young SCs (~10 Myr) is
comparable to the lifetime of massive stars. We show that mass-loss by stellar
winds influences the reversal of core collapse and the expansion of the
half-mass radius. In particular, the post-collapse re-expansion of the core is
weaker for metal-poor SCs than for metal-rich SCs, because the former lose less
mass (through stellar winds) than the latter. As a consequence, the half-mass
radius expands faster in metal-poor SCs. The difference in the half-light
radius between metal-poor SCs and metal-rich SCs is (up to a factor of two)
larger than the difference in the half-mass radius.