title: Minimal immersions of Riemannian manifolds in products of space forms

abstract:
  In this note, we give natural extensions to cylinders and tori of a classical
result due to T. Takahashi about minimal immersions into spheres. More
precisely, we deal with Euclidean isometric immersions whose projections in R^N
satisfy a spectral condition of their Laplacian.


title: Higgs bundles over elliptic curves

abstract:
  In this paper we study $G$-Higgs bundles over an elliptic curve when the
structure group $G$ is a classical complex reductive Lie group. Modifying the
notion of family, we define a new moduli problem for the classification of
semistable $G$-Higgs bundles of a given topological type over an elliptic curve
and we give an explicit description of the associated moduli space as a finite
quotient of a product of copies of the cotangent bundle of the elliptic curve.
We construct a bijective morphism from this new moduli space to the usual
moduli space of semistable $G$-Higgs bundles, proving that the former is the
normalization of the latter. We also obtain an explicit description of the
Hitchin fibration for our (new) moduli space of $G$-Higgs bundles and we study
the generic and non-generic fibres.


title:
Markov chain Monte Carlo methods for the regular two-level fractional
  factorial designs and cut ideals

abstract:
  It is known that a Markov basis of the binary graph model of a graph $G$
corresponds to a set of binomial generators of cut ideals $I_{\widehat{G}}$ of
the suspension $\widehat{G}$ of $G$. In this paper, we give another application
of cut ideals to statistics. We show that a set of binomial generators of cut
ideals is a Markov basis of some regular two-level fractional factorial design.
As application, we give a Markov basis of degree 2 for designs defined by at
most two relations.


title:
Fast and reliable identification of atomically thin layers of TaSe2
  crystals

abstract:
  Deposition of clean and defect-free atomically thin two-dimensional
crystalline flakes on surfaces by mechanical exfoliation of layered bulk
materials has proven to be a powerful technique, but it requires a fast,
reliable and non-destructive way to identify the atomically thin flakes among a
crowd of thick flakes. In this work, we provide general guidelines to identify
ultrathin flakes of TaSe2 by means of optical microscopy and Raman
spectroscopy. Additionally, we determine the optimal substrates to facilitate
the optical identification of atomically thin TaSe2 crystals. Experimental
realization and isolation of ultrathin layers of TaSe2 enables future studies
on the role of the dimensionality in interesting phenomena such as
superconductivity and charge density waves.


title:
Parton Shower Effects on W and Z Production via Vector Boson Fusion at
  NLO QCD

abstract:
  We present the implementation of electroweak Zjj and Wjj production via
vector boson fusion with fully leptonic decays at NLO QCD in the POWHEG
framework. These processes represent an important background to Higgs searches
in vector boson fusion, but they also can be seen as signal processes to study
anomalous triple vector boson couplings as well as the impact of a central jet
veto. Observables related to the third jet are sensitive to the parton shower
which is used, a fact which is demonstrated by a comparison between PYTHIA, the
standard angular-ordered HERWIG++ shower and the new p_T-ordered Dipole Shower
in HERWIG++.


title: Top properties in $t\bar{t}$ events at CMS (includes mass)

abstract:
  Selected results from the following topics are presented: Measurements of
several top quark properties are obtained from the CMS data collected in 2011
at a center-of-mass energy of 7 TeV. The results include measurements of the
top quark mass, the W helicity in top decays, the top quark charge, and of the
$t\bar{t}$ spin correlation and the search for anomalous couplings.


title:
Symmetric Monge-Kantorovich problems and polar decompositions of vector
  fields

abstract:
  For any given integer $N\geq 2$, we show that every bounded measurable vector
field from a bounded domain $\Omega$ into $\R^d$ is $N$-cyclically monotone up
to a measure preserving $N$-involution. The proof involves the solution of a
multidimensional symmetric Monge-Kantorovich problem, which we first study in
the case of a general cost function on a product domain $\Omega^N$. The polar
decomposition described above corresponds to a special cost function derived
from the vector field in question (actually $N-1$ of them). In this case, we
show that the supremum over all probability measures on $\Omega^N$ which are
invariant under cyclic permutations and with a given first marginal $\mu$, is
attained on a probability measure that is supported on the graph of a function
of the form $x\to (x, Sx, S^2x,..., S^{N-1}x)$, where $S$ is a $\mu$-measure
preserving transformation on $\Omega$ such that $S^N=I$ a.e. The proof exploits
a remarkable duality between such involutions and those Hamiltonians that are
$N$-cyclically antisymmetric.


title:
Theoretical formulation of Doppler redistribution in scattering
  polarization within the framework of the velocity-space density matrix
  formalism

abstract:
  Within the framework of the density matrix theory for the generation and
transfer of polarized radiation, velocity density matrix correlations represent
an important physical aspect that, however, is often neglected in practical
applications by adopting the simplifying approximation of complete
redistribution on velocity. In this paper, we present an application of the
Non-LTE problem for polarized radiation taking such correlations into account
through the velocity-space density matrix formalism. We consider a two-level
atom with infinitely sharp upper and lower levels, and we derive the
corresponding statistical equilibrium equations neglecting the contribution of
velocity-changing collisions. Coupling such equations with the radiative
transfer equations for polarized radiation, we derive a set of coupled
equations for the velocity-dependent source function. This set of equations is
then particularized to the case of a plane-parallel atmosphere. The equations
presented in this paper provide a complete and solid description of the physics
of pure Doppler redistribution, a phenomenon generally described within the
framework of the redistribution matrix formalism. The redistribution matrix
corresponding to this problem (generally referred to as R_I) is derived
starting from the statistical equilibrium equations for the velocity-space
density matrix and from the radiative transfer equations for polarized
radiation, thus showing the equivalence of the two approaches.


title: Hard exclusive processes

abstract:
  We present the theory of hard exclusive processes, at medium and asymptotical
energies, illustrated through some selected examples.


title:
A Parallel General Purpose Multi-Objective Optimization Framework, with
  Application to Beam Dynamics

abstract:
  Particle accelerators are invaluable tools for research in the basic and
applied sciences, in fields such as materials science, chemistry, the
biosciences, particle physics, nuclear physics and medicine. The design,
commissioning, and operation of accelerator facilities is a non-trivial task,
due to the large number of control parameters and the complex interplay of
several conflicting design goals. We propose to tackle this problem by means of
multi-objective optimization algorithms which also facilitate a parallel
deployment. In order to compute solutions in a meaningful time frame a fast and
scalable software framework is required. In this paper, we present the
implementation of such a general-purpose framework for simulation-based
multi-objective optimization methods that allows the automatic investigation of
optimal sets of machine parameters. The implementation is based on a
master/slave paradigm, employing several masters that govern a set of slaves
executing simulations and performing optimization tasks. Using evolutionary
algorithms as the optimizer and OPAL as the forward solver, validation
experiments and results of multi-objective optimization problems in the domain
of beam dynamics are presented. The high charge beam line at the Argonne
Wakefield Accelerator Facility was used as the beam dynamics model. The 3D beam
size, transverse momentum, and energy spread were optimized.


title:
The magnetic and crystal structures of Sr2IrO4: A neutron diffraction
  study

abstract:
  We report a single-crystal neutron diffraction study of the layered $\rm
Sr_2IrO_4$. This work unambiguously determines the magnetic structure of the
system and reveals that the spin orientation rigidly tracks the staggered
rotation of the $\rm IrO_6$ octahedra in $\rm Sr_2IrO_4$. The long-range
antiferromagnetic order has a canted spin configuration with an ordered moment
of 0.208(3) $\mu_B$/Ir site within the basal plane; a detailed examination of
the spin canting yields 0.202(3) and 0.049(2) $\mu_B$/site for the a axis and
the b axis, respectively. It is intriguing that forbidden nuclear reflections
of space group $I4_1/acd$ are also observed in a wide temperature range from 4
K to 600 K, which suggests a reduced crystal structure symmetry. This
neutron-scattering work provides a direct, well-refined experimental
characterization of the magnetic and crystal structures that are crucial to the
understanding of the unconventional magnetism exhibited in this unusual
magnetic insulator.


title:
Induction-Detection Electron Spin Resonance with Sensitivity of 1000
  Spins: En Route to Scalable Quantum Computations

abstract:
  Spin-based quantum computation (QC) in the solid state is considered to be
one of the most promising approaches to scalable quantum computers. However, it
faces problems such as initializing the spins, selectively addressing and
manipulating single spins, and reading out the state of the individual spins.
We have recently sketched a scheme that potentially solves all of these
problems5. This is achieved by making use of a unique phosphorus-doped 28Si
sample (28Si:P), and applying powerful new electron spin resonance (ESR)
techniques for parallel excitation, detection, and imaging in order to
implement QCs and efficiently obtain their results. The beauty of our proposed
scheme is that, contrary to other approaches, single-spin detection sensitivity
is not required and a capability to measure signals of ~100-1000 spins is
sufficient to implement it. Here we take the first experimental step towards
the actual implementation of such scheme. We show that, by making use of the
smallest ESR resonator constructed to date (~5 microns), together with a unique
cryogenic amplification scheme and sub-micron imaging capabilities, a
sensitivity of less than 1000 electron spin is obtained with spatial resolution
of ~500 nm. This is the most sensitive induction-detection experiment carried
out to date, and such capabilities put this approach on the fast track to the
demonstration of a scalable QC capability.


title:
Search for a Higgs boson decaying into a b-quark pair and produced in
  association with b quarks in proton-proton collisions at 7 TeV

abstract:
  A search for a neutral Higgs boson decaying to a pair of b quarks, and
produced in association with at least one additional b quark, is presented.
Multijet final states with three jets identified as originating from b quarks,
at least one of which may include a non-isolated muon, are studied. The data
used in this analysis correspond to an integrated luminosity of 2.7-4.8 inverse
femtobarns, collected by the CMS experiment in proton-proton collisions at the
LHC at a center-of-mass energy of 7 TeV. This search is particularly sensitive
to Higgs bosons in scenarios of the Minimal Supersymmetric Model (MSSM) with
large values of tan(beta). No excess over the predicted background from
standard model processes is observed. Stringent upper limits on cross section
times branching fraction are derived and interpreted as bounds in the MSSM
tan(beta) and M[A] parameter-space. Observed 95% confidence level upper limits
reach as low as tan(beta) approximately 18 for M[A] approximately 100 GeV.


title: Charm mixing at LHCb

abstract:
  We report a measurement of the time-dependent ratio of $D^0\to K^+\pi^-$ to
$D^0\to K^-\pi^+$ decay rates in $D^{*+}$-tagged events using 1.0\,fb$^{-1}$ of
integrated luminosity recorded by the LHCb experiment. We measure the mixing
parameters $x'^2=(-0.9\pm1.3)\times10^{-4}$, $y'=(7.2\pm2.4)\times10^{-3}$ and
the ratio of doubly-Cabibbo-suppressed to Cabibbo-favored decay rates
$R_D=(3.52\pm0.15)\times10^{-3}$. The result excludes the no-mixing hypothesis
with a probability corresponding to 9.1 standard deviations and represents the
first observation of charm mixing from a single measurement


title:
Effects of Family Nonuniversal Z' Boson on Leptonic Decays of Higgs and
  Weak Bosons

abstract:
  Though not completely a surprise according to the standard model and existing
indirect constraints, the Higgs-like particle, h, of mass around 125 GeV
recently observed at the LHC may offer an additional window to physics beyond
the standard model. In particular, its decay pattern can be modified by the
existence of new particles. One of the popular scenarios involves a Z' boson
associated with an extra Abelian gauge group. In this study, we explore the
potential effects of such a boson with family-nonuniversal couplings on the
leptonic decays of h, both flavor-conserving and flavor-changing. For current
constraints, we take into account leptonic decays at the Z pole, LEP II
scattering data, limits on various flavor-changing lepton transitions, and
lepton magnetic dipole moments. Adopting a model-independent approach and
assuming that the Z' has negligible mixing with the Z boson, we find that
present data allow the Z' effects to reach a few percent or higher on h decays
into a pair of leptons. Future measurements on h at the LHC or a linear
collider can therefore detect the Z' contributions or impose further
constraints on its couplings. We also consider Z'-mediated four-lepton decays
of the Z and W bosons.


title: Optimized random chemistry

abstract:
  The random chemistry algorithm of Kauffman can be used to determine an
unknown subset S of a fixed set V. The algorithm proceeds by zeroing in on S
through a succession of nested subsets V=V_0,V_1,...,V_m=S. In Kauffman's
original algorithm, the size of each V_i is chosen to be half the size of
V_{i-1}. In this paper we determine the optimal sequence of sizes so as to
minimize the expected run time of the algorithm.


title: Localization dynamics of fluids in random confinement

abstract:
  The dynamics of two-dimensional fluids confined within a random matrix of
obstacles is investigated using both colloidal model experiments and molecular
dynamics simulations. By varying fluid and matrix area fractions in the
experiment, we find delocalized tracer particle dynamics at small matrix area
fractions and localized motion of the tracers at high matrix area fractions. In
the delocalized region, the dynamics is subdiffusive at intermediate times, and
diffusive at long times, while in the localized regime, trapping in finite
pockets of the matrix is observed. These observations are found to agree with
the simulation of an ideal gas confined in a weakly correlated matrix. Our
results show that Lorentz gas systems with soft interactions are exhibiting a
smoothening of the critical dynamics and consequently a rounded
delocalization-to-localization transition.


title: Generation of single photons from an atom-cavity system

abstract:
  A single rubidium atom trapped within a high-finesse optical cavity is an
efficient source of single photons. We theoretically and experimentally study
single-photon generation using a vacuum stimulated Raman adiabatic passage. We
experimentally achieve photon generation efficiencies of up to 34% and 56% on
the D1 and D2 line, respectively. Output coupling with 89% results in
record-high efficiencies for single photons in one spatiotemporally
well-defined propagating mode. We demonstrate that the observed generation
efficiencies are constant in a wide range of applied pump laser powers and
virtual level detunings. This allows for independent control over the frequency
and wave packet envelope of the photons without loss in efficiency. In
combination with the long trapping time of the atom in the cavity, our system
constitutes a significant advancement toward an on-demand, highly efficient
single-photon source for quantum information processing tasks.


title: Mathematics in the Age of the Turing Machine

abstract:
  The article gives a survey of mathematical proofs that rely on computer
calculations and formal proofs.


title: Gorenstein cut polytopes

abstract:
  An integral convex polytope ${\mathcal P}$ is said to be Gorenstein if its
toric ring $K[{\mathcal P}]$ is normal and Gorenstein. In this paper,
Gorenstein cut polytopes of graphs are characterized explicitly. First, we
prove that Gorenstein cut polytopes are compressed (i.e., all of whose reverse
lexicographic triangulations are unimodular). Second, by applying
Athanasiadis's theory for Gorenstein compressed polytopes, we show that a cut
polytope of a graph $G$ is Gorenstein if and only if $G$ has no $K_5$-minor and
$G$ is either a bipartite graph without induced cycles of length $\geq 6$ or a
bridgeless chordal graph.


title:
Finite-size scaling method for the Berezinskii-Kosterlitz-Thouless
  transition

abstract:
  We test an improved finite-size scaling method for reliably extracting the
critical temperature $T_{\rm BKT}$ of a Berezinskii-Kosterlitz-Thouless (BKT)
transition. Using known single-parameter logarithmic corrections to the spin
stiffness $\rho_s$ at $T_{\rm BKT}$ in combination with the Kosterlitz-Nelson
relation between the transition temperature and the stiffness, $\rho_s(T_{\rm
BKT})=2T_{\rm BKT}/\pi$, we define a size dependent transition temperature
$T_{\rm BKT}(L_1,L_2)$ based on a pair of system sizes $L_1,L_2$, e.g.,
$L_2=2L_1$. We use Monte Carlo data for the standard two-dimensional classical
XY model to demonstrate that this quantity is well behaved and can be reliably
extrapolated to the thermodynamic limit using the next expected logarithmic
correction beyond the ones included in defining $T_{\rm BKT}(L_1,L_2)$. For the
Monte Carlo calculations we use GPU (graphical processing unit) computing to
obtain high-precision data for $L$ up to 512. We find that the sub-leading
logarithmic corrections have significant effects on the extrapolation. Our
result $T_{\rm BKT}=0.8935(1)$ is several error bars above the previously best
estimates of the transition temperature; $T_{\rm BKT} \approx 0.8929$. If only
the leading log-correction is used, the result is, however, consistent with the
lower value, suggesting that previous works have underestimated $T_{\rm BKT}$
because of neglect of sub-leading logarithms. Our method is easy to implement
in practice and should be applicable to generic BKT transitions.


title:
Fluctuation-induced noise in out-of-equilibrium disordered
  superconducting films

abstract:
  We study out-of-equilibrium transport in disordered superconductors close to
the superconducting transition. We consider a thin film connected by resistive
tunnel interfaces to thermal reservoirs having different chemical potentials
and temperatures. The nonequilibrium longitudinal current-current correlation
function is calculated within the nonlinear sigma model description and
nonlinear dependence on temperatures and chemical potentials is obtained.
Different contributions are calculated, originating from the
fluctuation-induced suppression of the quasiparticle density of states, Maki-
Thompson and Aslamazov-Larkin processes. As a special case of our results,
close-to-equilibrium we obtain the longitudinal ac conductivity using the
fluctuation-dissipation theorem.


title: Quasicomplex N=2, d=1 Supersymmetric Sigma Models

abstract:
  We derive and discuss a new type of N=2 supersymmetric quantum mechanical
sigma models which appear when the superfield action of the (1,2,1) multiplets
is modified by adding an imaginary antisymmetric tensor to the target space
metric, thus completing the latter to a non-symmetric Hermitian metric. These
models are not equivalent to the standard de Rham sigma models, but are related
to them through a certain special similarity transformation of the
supercharges. On the other hand, they can be obtained by a Hamiltonian
reduction from the complex supersymmetric N=2 sigma models built on the
multiplets (2,2,0) and describing the Dolbeault complex on the manifolds with
proper isometries. We study in detail the extremal two-dimensional case, when
the target space metric is defined solely by the antisymmetric tensor, and show
that the corresponding quantum systems reveal a hidden N=4 supersymmetry.


title:
Slavnov-Taylor identities, non-commutative gauge theories and infrared
  divergences

abstract:
  In this work we clarify some properties of the one-loop IR divergences in
non-Abelian gauge field theories on non-commutative 4-dimensional Moyal space.
Additionally, we derive the tree-level Slavnov-Taylor identities relating the
two, three and four point functions, and verify their consistency with the
divergent one-loop level results. We also discuss the special case of two
dimensions.


title: One-dimensional array of ion chains coupled to an optical cavity

abstract:
  We present a novel hybrid system where an optical cavity is integrated with a
microfabricated planar-electrode ion trap. The trap electrodes produce a
tunable periodic potential allowing the trapping of up to 50 separate ion
chains spaced by 160 $\mu$m along the cavity axis. Each chain can contain up to
20 individually addressable Yb\textsuperscript{+} ions coupled to the cavity
mode. We demonstrate deterministic distribution of ions between the sites of
the electrostatic periodic potential and control of the ion-cavity coupling.
The measured strength of this coupling should allow access to the strong
collective coupling regime with $\lesssim$10 ions. The optical cavity could
serve as a quantum information bus between ions or be used to generate a strong
wavelength-scale periodic optical potential.


title: Evidence for galaxies being pre-processed before accreted into clusters

abstract:
  I use the spectroscopic data for galaxies in and around nearby (0.02<z<0.06)
X-ray bright galaxy clusters, to show that the incidence of k+a (or
post-starburst) galaxies (EW(Ha)<2 ang in emission and EW(Hd)>3 ang in
absorption) may be correlated with the accretion of small galaxy groups in
clusters. At r<2r200, the k+a galaxies are found in regions of higher galaxy
density relative to other cluster galaxies. The k+a galaxies have a positively
skewed distribution of absolute velocity,|v_los|/sigma_v, where v_los is the
difference between the line-of-sight velocity of the galaxy and the cluster's
mean, and sigma_v is the cluster's velocity dispersion. This distribution is
statistically different from that of other cluster galaxies within 2r200, and
in the same absolute velocity range. Moreover, 87% of clusters in the sample
studied here show statistically significant substructure in their velocity
distribution, and 91.4% of all k+a galaxies are found to be a part of one of
these substructures with 4-10 members. These results suggest that star
formation in these k+a galaxies is likely to have been quenched due to
"pre-processing" in a poor group-like environment before they are accreted into
clusters. I also find a mild, but statistically significant trend in the
fraction of k+a galaxies increasing with the temperature of the X-ray emitting
gas in clusters.


title: Predicting evolution and visualizing high-dimensional fitness landscapes

abstract:
  The tempo and mode of an adaptive process is strongly determined by the
structure of the fitness landscape that underlies it. In order to be able to
predict evolutionary outcomes (even on the short term), we must know more about
the nature of realistic fitness landscapes than we do today. For example, in
order to know whether evolution is predominantly taking paths that move upwards
in fitness and along neutral ridges, or else entails a significant number of
valley crossings, we need to be able to visualize these landscapes: we must
determine whether there are peaks in the landscape, where these peaks are
located with respect to one another, and whether evolutionary paths can connect
them. This is a difficult task because genetic fitness landscapes (as opposed
to those based on traits) are high-dimensional, and tools for visualizing such
landscapes are lacking. In this contribution, we focus on the predictability of
evolution on rugged genetic fitness landscapes, and determine that peaks in
such landscapes are highly clustered: high peaks are predominantly close to
other high peaks. As a consequence, the valleys separating such peaks are
shallow and narrow, such that evolutionary trajectories towards the highest
peak in the landscape can be achieved via a series of valley crossings


title:
Suzaku X-Ray Observations of the Accreting NGC 4839 Group of Galaxies
  and the Radio Relic in the Coma Cluster

abstract:
  Based on Suzaku X-ray observations, we study the hot gas around the NGC4839
group of galaxies and the radio relic in the outskirts of the Coma cluster. We
find a gradual decline in the gas temperature from 5 keV around NGC4839 to 3.6
keV at the radio relic, across which there is a further, steeper drop down to
1.5 keV. This drop as well as the observed surface brightness profile are
consistent with a shock with Mach number M = 2.2 pm 0.5 and velocity vs = (1410
pm 110) km s^-1. A lower limit of B > 0.33 mu G is derived on the magnetic
field strength around the relic from upper limits to inverse Compton X-ray
emission. Although this suggests that the non-thermal electrons responsible for
the relic are generated by diffusive shock acceleration (DSA), the relation
between the measured Mach number and the electron spectrum inferred from radio
observations are inconsistent with that expected from the simplest,
test-particle theory of DSA. Nevertheless, DSA is still viable if it is
initiated by the injection of a pre-existing population of non-thermal
electrons. Combined with previous measurements, the temperature profile of Coma
in the southwest direction is shallower outside NGC4839 and also slightly
shallower in the outermost region. The metal abundance around NGC4839 is
confirmed to be higher than in its vicinity, implying a significant peak in the
abundance profile that decreases to 0.2 solar toward the outskirts. We
interpret these facts as due to ram pressure stripping of metal-enriched gas
from NGC4839 as it falls into Coma. The relic shock may result from the
combined interaction of pre-existing intracluster gas, gas associated with NGC
4839, and cooler gas flowing in from the large-scale structure filament in the
southwest.


title: Symmetry of Differential Equations and Quantum Theory

abstract:
  The symmetry study of main differential equations of mechanics and
electrodynamics has shown, that differential equations, which are invariant
under transformations of groups, which are symmetry groups of mathematical
numbers (considered within the frames of the number theory) determine the
mathematical nature of the quantities, incoming in given equations. It allowed
to proof the main postulate of quantum mechanics, consisting in that, that to
any mechanical quantity can be set up into the correspondence the Hermitian
matrix by quantization.
  High symmetry of Maxwell equations allows to show, that to quantities,
incoming in given equations can be set up into the correspondence the
Quaternion (twice-Hermitian) matrix by their quantization.
  It is concluded, that the equations of the dynamics of mechanical systems are
not invariant under transformations of quaternion multiplicative group and,
consecuently, direct application of quaternions with usually used basis \{e, i,
j, k \} to build the new version of quantum mechanics, which was undertaken in
the number of modern publications, is incorrect. It is the consequence of
non-abelian character of given group. At the same time we have found the
correct ways for the creation of the new versions of quantum mechanics on the
quaternion base by means of choice of new bases in quaternion ring, from which
can be formed the bases for complex numbers under multiplicative groups of
which the equations of the dynamics of mechanical systems are invariant.


title: Risk estimation for LCF crack initiation

abstract:
  An accurate risk assessment for fatigue damage is of vital importance for the
design and service of today's turbomachinery components. We present an approach
for quantifying the probability of crack initiation due to surface driven
low-cycle fatigue (LCF). This approach is based on the theory of failure-time
processes and takes inhomogeneous stress fields and size effects into account.
The method has been implemented as a finite-element postprocessor which uses
quadrature formulae of higher order. Results of applying this new approach to
an example case of a gas-turbine compressor disk are discussed.


title:
General Rotational Surfaces with Pointwise 1-Type Gauss Map in Pseudo-
  Euclidean Space E42

abstract:
  In this paper, we study general rotational surfaces in the 4- dimensional
pseudo-Euclidean space E4-2 and obtain a characterization of flat general
rotation surfaces with pointwise 1-type Gauss map in E4-2 and give an example
of such surfaces.


title:
Role Of Generalized Cosmic Chaplygin Gas In Accelerating Universe : A
  Field Theoretical Prescription

abstract:
  In this paper we investigate the role played by dark energy in the form of
Generalized cosmic Chaplygin gas in an accelerating universe described by FRW
cosmology. We have tried to describe the model from the theoretical point of
view of a field, by introducing a scalar field $\phi$ and a self interacting
potential $V(\phi)$. The corresponding expressions for the field are obtained
for the given model. Statefinder parameters have been used to characterize the
dark energy model. Plots have been generated for characterizing different
phases of universe diagrammatically and a comparative study is performed with
the Modified Chaplygin gas model. As an outcome of the study, Generalized
cosmic Chaplygin gas is identified as a much less constrained form of dark
energy as compared to modified Chaplygin gas.


title:
Galaxy environments over cosmic time: the non-evolving radial galaxy
  distributions around massive galaxies since z=1.6

abstract:
  We present a statistical study of the environments of massive galaxies in
four redshift bins between z=0.04 and z=1.6, using data from the Sloan Digital
Sky Survey (SDSS) and the NEWFIRM Medium Band Survey (NMBS). We measure the
projected radial distribution of galaxies in cylinders around a constant number
density selected sample of massive galaxies and utilize a statistical
subtraction of contaminating sources. Our analysis shows that massive primary
galaxies typically live in group halos and are surrounded by 2 to 3 satellites
with masses more than one-tenth of the primary galaxy mass. The cumulative
stellar mass in these satellites roughly equals the mass of the primary galaxy
itself. We further find that the radial number density profile of galaxies
around massive primaries has not evolved significantly in either slope or
overall normalization in the past 9.5 Gyr. A simplistic interpretation of this
result can be taken as evidence for a lack of mergers in the studied groups and
as support for a static evolution model of halos containing massive primaries.
Alternatively, there exists a tight balance between mergers and accretion of
new satellites such that the overall distribution of galaxies in and around the
halo is preserved. The latter interpretation is supported by a comparison to a
semi-analytic model, which shows a similar constant average satellite
distribution over the same redshift range.


title:
Helium-ignited violent mergers as a unified model for normal and rapidly
  declining Type Ia Supernovae

abstract:
  The progenitors of Type Ia Supernovae (SNe Ia) are still unknown, despite
significant progress during the last years in theory and observations. Violent
mergers of two carbon--oxygen (CO) white dwarfs (WDs) are one candidate
suggested to be responsible for at least a significant fraction of normal SNe
Ia. Here, we simulate the merger of two CO WDs using a moving-mesh code that
allows for the inclusion of thin helium (He) shells (0.01\,\msun) on top of the
WDs, at an unprecedented numerical resolution. The accretion of He onto the
primary WD leads to the formation of a detonation in its He shell. This
detonation propagates around the CO WD and sends a converging shock wave into
its core, known to robustly trigger a second detonation, as in the well-known
double-detonation scenario for
  He-accreting CO WDs. However, in contrast to that scenario where a massive He
shell is required to form a detonation through thermal instability, here the He
detonation is ignited dynamically. Accordingly the required He-shell mass is
significantly smaller, and hence its burning products are unlikely to affect
the optical display of the explosion. We show that this scenario, which works
for CO primary WDs with CO- as well as He-WD companions, has the potential to
explain the different brightness distributions, delay times and relative rates
of normal and fast declining SNe Ia. Finally, we discuss extensions to our
unified merger model needed to obtain a comprehensive picture of the full
observed diversity of SNe Ia.


title:
The double pulsar: evidence for neutron star formation without an iron
  core-collapse supernova

abstract:
  The double pulsar system PSR J0737-3039A/B is a double neutron star binary,
with a 2.4-hour orbital period, which has allowed measurement of relativistic
orbital perturbations to high precision. The low mass of the second-formed
neutron star, as well as the low system eccentricity and proper motion, point
to a different evolutionary scenario compared to most other known double
neutron star systems. We describe analysis of the pulse profile shape over 6
years of observations, and present the resulting constraints on the system
geometry. We find the recycled pulsar in this system, PSR J0737-3039A, to be a
near-orthogonal rotator, with an average separation between its spin and
magnetic axes of 90 +/- 11 +/- 5 deg. Furthermore, we find a mean 95% upper
limit on the misalignment between its spin and orbital angular momentum axes of
3.2 deg, assuming that the observed emission comes from both magnetic poles.
This tight constraint lends credence to the idea that the supernova that formed
the second pulsar was relatively symmetric, possibly involving electron-capture
onto an O-Ne-Mg core.


title:
Hybrid dynamical electroweak symmetry breaking with heavy quarks and the
  125 GeV Higgs

abstract:
  Existing models of dynamical electroweak symmetry breaking (EWSB) find it
very difficult to get a Higgs of mass lighter than $m_t$. Consequently, in
light of the LHC discovery of the ~125 GeV Higgs, such models face a
significant obstacle. Moreover, with three generations those models have a
superheavy cut-off around $10^{17}$ GeV, requiring a significant fine-tuning.
To overcome these twin difficulties, we propose a hybrid framework for EWSB, in
which the Higgs mechanism is combined with a Nambu-Jona-Lasinio mechanism. The
model introduces a strongly coupled doublet of heavy quarks with a mass around
500 GeV, which forms a condensate at a compositeness scale $\Lambda$ about a
few TeV, and an additional unconstrained scalar doublet which behaves as a
"fundamental" doublet at $\Lambda$. This "fundamental"-like doublet has a
vanishing quartic term at $\Lambda$ and is, therefore, not the SM doublet, but
should rather be viewed as a pseudo-Goldstone boson of the underlying strong
dynamics. This setup is matched at the compositeness scale $\Lambda$ to a
tightly constrained hybrid two Higgs doublet model, where both the composite
and unconstrained scalars participate in EWSB. This allows us to get a good
candidate for the recently observed 125 GeV scalar which has properties very
similar to the Standard Model Higgs. The heavier (mostly composite) CP-even
scalar has a mass around 500 GeV, while the pseudoscalar and the charged Higgs
particles have masses in the range 200 -300 GeV.


title: Circumstellar absorption in double detonation Type Ia supernovae

abstract:
  Upon formation, degenerate He core white dwarfs are surrounded by a radiative
H-rich layer primarily supported by ideal gas pressure. In this Letter, we
examine the effect of this H-rich layer on mass transfer in He+C/O double white
dwarf binaries that will eventually merge and possibly yield a Type Ia
supernova (SN Ia) in the double detonation scenario. Because its thermal
profile and equation of state differ from the underlying He core, the H-rich
layer is transferred stably onto the C/O white dwarf prior to the He core's
tidal disruption. We find that this material is ejected from the binary system
and sweeps up the surrounding interstellar medium hundreds to thousands of
years before the SN Ia. The close match between the resulting circumstellar
medium profiles and values inferred from recent observations of circumstellar
absorption in SNe Ia gives further credence to the resurgent double detonation
scenario.


title: Critical Exponents for Supercooled Liquids

abstract:
  We compute critical exponents governing universal features of supercooled
liquids through the effective theory of an overlap field. The correlation
length diverges with the Ising exponent; the size of dynamically heterogeneous
patches grows more rapidly; and the relaxation time obeys a generalized
Vogel-Fulcher-Tammann relation.


title: One-loop Chern-Simons terms in five dimensions

abstract:
  We compute one-loop corrections to five-dimensional gauge and gravitational
Chern-Simons terms induced by integrating out charged massive fields. The
considered massive fields are spin-1/2 and spin-3/2 fermions, as well as
complex two-forms with first order kinetic terms. Consistency with
six-dimensional gravitational anomalies of (1,0) and (2,0) theories is shown by
interpreting the massive fields as excited Kaluza-Klein modes in a circle
compactification. The results are in accordance with the geometric predictions
of the M-theory to F-theory duality as well as the comparison with an explicit
one-loop computation in heterotic string theory compactified on K3 x S^1.


title:
Angular velocity of gravitational radiation from precessing binaries and
  the corotating frame

abstract:
  This paper defines an angular velocity for time-dependent functions on the
sphere, and applies it to gravitational waveforms from compact binaries.
Because it is geometrically meaningful and has a clear physical motivation, the
angular velocity is uniquely useful in helping to solve an important---and
largely ignored---problem in models of compact binaries: the inverse problem of
deducing the physical parameters of a system from the gravitational waves
alone. It is also used to define the corotating frame of the waveform. When
decomposed in this frame, the waveform has no rotational dynamics and is
therefore as slowly evolving as possible. The resulting simplifications lead to
straightforward methods for accurately comparing waveforms and constructing
hybrids. As formulated in this paper, the methods can be applied robustly to
both precessing and nonprecessing waveforms, providing a clear, comprehensive,
and consistent framework for waveform analysis. Explicit implementations of all
these methods are provided in accompanying computer code.


title: PRIMUS: Infrared and X-ray AGN Selection Techniques at 0.2<z<1.2

abstract:
  We present a study of Spitzer/IRAC and X-ray active galactic nuclei (AGNs)
selection techniques in order to quantify the overlap, uniqueness,
contamination, and completeness of each. We investigate how the overlap and
possible contamination of the samples depends on the IR and X-ray depths. We
use Spitzer/IRAC imaging, Chandra and XMM X-ray imaging, and PRism MUlti-object
Survey (PRIMUS) spectroscopic redshifts to construct galaxy and AGN samples at
0.2<z<1.2 over 8 deg^2. We construct samples over a wide range of IRAC flux
limits (SWIRE to GOODS depth) and X-ray flux limits (10 ks to 2 Ms). We compare
IR-AGN samples defined using the IRAC color selection of Stern et al. and
Donley et al. with X-ray detected AGN samples. For roughly similar depth IR and
X-ray surveys, we find that ~75% of IR-AGN are identified as X-ray AGN. This
fraction increases to ~90% when comparing against the deepest X-ray data,
indicating that only ~10% of IR-selected AGN may be heavily obscured. The
IR-AGN selection proposed by Stern et al. suffers from contamination by
star-forming galaxies at various redshifts when using deeper IR data, though
the selection technique works well for shallow IR data. While similar overall,
the IR-AGN samples preferentially contain more luminous AGN, while the X-ray
AGN samples preferentially contain lower specific accretion rate AGN, where the
host galaxy light dominates at IR wavelengths. The host galaxy populations of
the IR and X-ray AGN samples have similar restframe colors and stellar masses;
both selections identify AGN in blue, star-forming and red, quiescent galaxies.


title:
Realization of Pristine and Locally-Tunable One-Dimensional Electron
  Systems in Carbon Nanotubes

abstract:
  Recent years have seen the development of several experimental systems
capable of tuning local parameters of quantum Hamiltonians. Examples include
ultracold atoms, trapped ions, superconducting circuits, and photonic crystals.
By design, these systems possess negligible disorder, granting them a high
level of tunability. Conversely, electrons in conventional condensed matter
systems exist inside an imperfect host material, subjecting them to
uncontrollable, random disorder, which often destroys delicate correlated
phases and precludes local tunability. The realization of a condensed matter
system that is disorder-free and locally-tunable thus remains an outstanding
challenge. Here, we demonstrate a new technique for deterministic creation of
locally-tunable, ultra-low-disorder electron systems in carbon nanotubes
suspended over circuits of unprecedented complexity. Using transport
experiments we show that electrons can be localized at any position along the
nanotube and that the confinement potential can be smoothly moved from location
to location. Nearly perfect mirror symmetry of transport characteristics about
the centre of the nanotube establishes the negligible effects of electronic
disorder, thus allowing experiments in precision engineered one-dimensional
potentials. We further demonstrate the ability to position multiple nanotubes
at chosen separations, generalizing these devices to coupled one-dimensional
systems. These new capabilities open the door to a broad spectrum of new
experiments on electronics, mechanics, and spins in one dimension.


title: Mott Transition and Glassiness in the Face Centered Cubic Lattice

abstract:
  We study the half-filled Hubbard model on the geometrically frustrated face
centered cubic (FCC) lattice, using an auxiliary field based real space
technique. The low temperature state is a paramagnetic metal at weak
interaction, an antiferromagnetic insulator (AFI) with flux like order at
intermediate interaction, and an AFI with `C type' order at very strong
interaction. Remarkably, there is a narrow window between the paramagnetic
metal and the AFI where the system exhibits spin glass behaviour arising from
the presence of disordered but `frozen' local moments. The spin glass state is
metallic at weaker interaction but shows crossover to pseudogap behaviour and
an insulating resistivity with growing interaction. We compare our results to
available experiments on FCC and pyrochlore based materials and suggest that
several of these features are typical of three dimensional correlated systems
with geometric frustration.


title: Lepton Asymmetry and Neutrino Oscillations Interplay

abstract:
  We discuss the interplay between lepton asymmetry L and neutrino oscillations
in the early Universe. Neutrino oscillations may suppress or enhance previously
existing L. On the other hand L is capable to suppress or enhance neutrino
oscillations. The mechanism of L enhancement in MSW resonant neutrino
oscillations in the early Universe is numerically analyzed. L cosmological
effects through neutrino oscillations are discussed.
  We discuss how L may change the cosmological BBN constraints on neutrino and
show that BBN model with electron-sterile neutrino oscillations is extremely
sensitive to L - it allows to obtain the most stringent constraints on L value.
We discuss also the cosmological role of active-sterile neutrino mixing and L
in connection with the indications about additional relativistic density in the
early Universe, pointed out by BBN, CMB and LSS data and the analysis of global
neutrino data.


title: Quantum quenches of holographic plasmas

abstract:
  We employ holographic techniques to study quantum quenches at finite
temperature, where the quenches involve varying the coupling of the boundary
theory to a relevant operator with an arbitrary conformal dimension
$2\leq\D\leq4$. The evolution of the system is studied by evaluating the
expectation value of the quenched operator and the stress tensor throughout the
process. The time dependence of the new coupling is characterized by a fixed
timescale and the response of the observables depends on the ratio of the this
timescale to the initial temperature. The observables exhibit universal scaling
behaviours when the transitions are either fast or slow, i.e. when this ratio
is very small or very large. The scaling exponents are smooth functions of the
operator dimension. We find that in fast quenches, the relaxation time is set
by the thermal timescale regardless of the operator dimension or the precise
quenching rate.


title:
Standardizing Type Ia Supernova Absolute Magnitudes Using Gaussian
  Process Data Regression

abstract:
  We present a novel class of models for Type Ia supernova time-evolving
spectral energy distributions (SED) and absolute magnitudes: they are each
modeled as stochastic functions described by Gaussian processes. The values of
the SED and absolute magnitudes are defined through well-defined regression
prescriptions, so that data directly inform the models. As a proof of concept,
we implement a model for synthetic photometry built from the spectrophotometric
time series from the Nearby Supernova Factory. Absolute magnitudes at peak $B$
brightness are calibrated to 0.13 mag in the $g$-band and to as low as 0.09 mag
in the $z=0.25$ blueshifted $i$-band, where the dispersion includes
contributions from measurement uncertainties and peculiar velocities. The
methodology can be applied to spectrophotometric time series of supernovae that
span a range of redshifts to simultaneously standardize supernovae together
with fitting cosmological parameters.


title:
Spectroscopic Observations of SN 2012fr: A Luminous Normal Type Ia
  Supernova with Early High Velocity Features and Late Velocity Plateau

abstract:
  We present 65 optical spectra of the Type Ia supernova SN 2012fr, of which 33
were obtained before maximum light. At early times SN 2012fr shows clear
evidence of a high-velocity feature (HVF) in the Si II 6355 line which can be
cleanly decoupled from the lower velocity "photospheric" component. This Si II
6355 HVF fades by phase -5; subsequently, the photospheric component exhibits a
very narrow velocity width and remains at a nearly constant velocity of
v~12,000 km/s until at least 5 weeks after maximum brightness. The Ca II
infrared (IR) triplet exhibits similar evidence for both a photospheric
component at v~12,000 km/s with narrow line width and long velocity plateau, as
well as a high-velocity component beginning at v~31,000 km/s two weeks before
maximum. SN 2012fr resides on the border between the "shallow silicon" and
"core-normal" subclasses in the Branch et al. (2009) classification scheme, and
on the border between normal and "high-velocity" SNe Ia in the Wang et al.
(2009a) system. Though it is a clear member of the "low velocity gradient"
(LVG; Benetii et al., 2005) group of SNe Ia and exhibits a very slow
light-curve decline, it shows key dissimilarities with the overluminous SN
1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed
SN Ia at the luminous end of the normal SN Ia distribution, and a key
transitional event between nominal spectroscopic subclasses of SNe Ia.


title:
Cosmic-ray diffusion in a sectored magnetic field in the distant
  heliosheath

abstract:
  Very high intensities of galactic cosmic rays measured by Voyager 1 in the
heliosheath appear to be incompatible with the presence of a modulation "wall"
near the heliopause produced by a pile up of the heliospheric magnetic field.
We propose that the modulation wall is a structure permeable to cosmic rays as
a result of a sectored magnetic field topology compressed by plasma slowdown on
approach to the heliopause and stretched to high latitudes by latitudinal flows
in the heliosheath. The tightly folded warped current sheet permits efficient
cosmic-ray transport in the radial direction via a drift-like mechanism. We
show that when stochastic variations in the sector widths are taken into
account, particle transport becomes predominantly diffusive both along and
across the magnetic sectors. Using a test-particle model for cosmic rays in the
heliosheath we investigate the dependence of the diffusion coefficients on the
properties of the sector structure and on particle energy.


title:
Modulated Ground State of Gravity Theories with Stabilized Conformal
  Factor

abstract:
  We discuss the stabilization of the conformal factor by higher derivative
terms in a conformally reduced $R+R^2$ Euclidean gravity theory. The flat
spacetime is unstable towards the condensation of modes with nonzero momentum,
and they "condense" in a modulated phase above a critical value of the coupling
$\beta$ of the $R^2$ term. By employing a combination of variational, numerical
and lattice methods we show that in the semiclassical limit the corresponding
functional integral is dominated by a single nonlinear plane wave of frequency
$\approx 1/\sqrt{\beta} \lp$. We argue that the ground state of the theory is
characterized by a spontaneous breaking of translational invariance at
Planckian scales.


title:
Measurement of the cross-section for W boson production in association
  with b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

abstract:
  This paper reports a measurement of the W+b-jets production cross-section in
proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC. These
results are based on data corresponding to an integrated luminosity of 4.6
fb-1, collected with the ATLAS detector. Cross-sections are presented as a
function of jet multiplicity and of the transverse momentum of the leading
b-jet for both the muon and electron decay modes of the W boson. The W+b-jets
cross-section, corrected for all known detector effects, is quoted in a limited
kinematic range, using jets reconstructed with the anti-k_t clustering
algorithm with transverse momentum above 25 GeV and rapidity within +/- 2.1.
Combining the muon and electron channels, the fiducial cross-section for
W+b-jets is measured to be 7.1 +/- 0.5 (stat) +/- 1.4 (syst) pb, consistent
with next-to-leading order QCD calculations within 1.5 standard deviations.


title: Probing the inner structure of distant AGNs with gravitational lensing

abstract:
  Microlensing is a powerful technique which can be used to study the continuum
and the broad line emitting regions in distant AGNs. After a brief description
of the methods and required data, we present recent applications of this
technique. We show that microlensing allows one to measure the temperature
profile of the accretion disc, estimate the size and study the geometry of the
region emitting the broad emission lines.


title: Flat bi-Hamiltonian structures and invariant densities

abstract:
  A bi-Hamiltonian structure is a pair of Poisson structures $\mathcal P$,
$\mathcal Q$ which are compatible, meaning that any linear combination $\alpha
\mathcal P + \beta \mathcal Q$ is again a Poisson structure. A bi-Hamiltonian
structure $(\mathcal P, \mathcal Q)$ is called flat if $\mathcal P$ and
$\mathcal Q$ can be simultaneously brought to a constant form in a neighborhood
of a generic point. We prove that a generic bi-Hamiltonian structure $(\mathcal
P, \mathcal Q)$ on an odd-dimensional manifold is flat if and only if there
exists a local density which is preserved by all vector fields Hamiltonian with
respect to $\mathcal P$, as well as by all vector fields Hamiltonian with
respect to $\mathcal Q$.


title:
Atoms and Molecules in Intense Laser Fields: Gauge Invariance of Theory
  and Models

abstract:
  Gauge invariance was discovered in the development of classical
electromagnetism and was required when the latter was formulated in terms of
the scalar and vector potentials. It is now considered to be a fundamental
principle of nature, stating that different forms of these potentials yield the
same physical description: they describe the same electromagnetic field as long
as they are related to each other by gauge transformations. Gauge invariance
can also be included into the quantum description of matter interacting with an
electromagnetic field by assuming that the wave function transforms under a
given local unitary transformation. The result of this procedure is a quantum
theory describing the coupling of electrons, nuclei and photons. Therefore, it
is a very important concept: it is used in almost every fields of physics and
it has been generalized to describe electroweak and strong interactions in the
standard model of particles. A review of quantum mechanical gauge invariance
and general unitary transformations is presented for atoms and molecules in
interaction with intense short laser pulses, spanning the perturbative to
highly nonlinear nonperturbative interaction regimes. Various unitary
transformations for single spinless particle Time Dependent Schr\"odinger
Equations, TDSE, are shown to correspond to different time-dependent
Hamiltonians and wave functions. Accuracy of approximation methods involved in
solutions of TDSE's such as perturbation theory and popular numerical methods
depend on gauge or representation choices which can be more convenient due to
faster convergence criteria. We focus on three main representations: length and
velocity gauges, in addition to the acceleration form which is not a gauge, to
describe perturbative and nonperturbative radiative interactions. Numerical
schemes for solving TDSE's in different representations are also discussed.


title:
Bilinear Strichartz estimates for the Zakharov-Kuznetsov equation and
  applications

abstract:
  This article is concerned with the Zakharov-Kuznetsov equation {equation}
\label{ZK0} \partial_tu+\partial_x\Delta u+u\partial_xu=0 . {equation} We prove
that the associated initial value problem is locally well-posed in $H^s(\mathbb
R^2)$ for $s>\frac12$ and globally well-posed in $H^1(\mathbb R\times \mathbb
T)$ and in $H^s(\R^3) $ for $ s>1$. Our main new ingredient is a bilinear
Strichartz estimate in the context of Bourgain's spaces which allows to control
the high-low frequency interactions appearing in the nonlinearity of
\eqref{ZK0}. In the $\mathbb R^2$ case, we also need to use a recent result by
Carbery, Kenig and Ziesler on sharp Strichartz estimates for homogeneous
dispersive operators. Finally, to prove the global well-posedness result in $
\R^3 $, we need to use the atomic spaces introduced by Koch and Tataru.


title: Impact of gluon damping on heavy-quark quenching

abstract:
  In this conference contribution, we discuss the influence of
gluon-bremsstrahlung damping in hot, absorptive QCD matter on the heavy-quark
radiation spectra. Within our Monte-Carlo implementation for the description of
the heavy-quark in-medium propagation we demonstrate that as a consequence of
gluon damping the quenching of heavy quarks becomes significantly affected at
higher transverse momenta.


title: The D-topology for diffeological spaces

abstract:
  Diffeological spaces are generalizations of smooth manifolds which include
singular spaces and function spaces. For each diffeological space,
Iglesias-Zemmour introduced a natural topology called the $D$-topology.
However, the $D$-topology has not yet been studied seriously in the existing
literature. In this paper, we develop the basic theory of the $D$-topology for
diffeological spaces. We explain that the topological spaces that arise as the
$D$-topology of a diffeological space are exactly the $\Delta$-generated spaces
and give results and examples which help to determine when a space is
$\Delta$-generated. Our most substantial results show how the $D$-topology on
the function space $C^{\infty}(M,N)$ between smooth manifolds compares to other
well-known topologies.


title:
Scattering of quantum wave packets by shallow potential islands: A
  quantum lens

abstract:
  We consider the problem of quantum scattering of a localized wave packet by a
weak Gaussian potential in two spatial dimensions. We show that, under certain
conditions, this problem bears close analogy with that of focusing (or
defocusing) of light rays by a thin optical lens: Quantum interference between
straight paths yields the same lens equation as for refracted rays in classical
optics.


title: The Biological Origin of Linguistic Diversity

abstract:
  In contrast with animal communication systems, diversity is characteristic of
almost every aspect of human language. Languages variously employ tones,
clicks, or manual signs to signal differences in meaning; some languages lack
the noun-verb distinction (e.g., Straits Salish), whereas others have a
proliferation of fine-grained syntactic categories (e.g., Tzeltal); and some
languages do without morphology (e.g., Mandarin), while others pack a whole
sentence into a single word (e.g., Cayuga). A challenge for evolutionary
biology is to reconcile the diversity of languages with the high degree of
biological uniformity of their speakers. Here, we model processes of language
change and geographical dispersion and find a consistent pressure for flexible
learning, irrespective of the language being spoken. This pressure arises
because flexible learners can best cope with the observed high rates of
linguistic change associated with divergent cultural evolution following human
migration. Thus, rather than genetic adaptations for specific aspects of
language, such as recursion, the coevolution of genes and fast-changing
linguistic structure provides the biological basis for linguistic diversity.
Only biological adaptations for flexible learning combined with cultural
evolution can explain how each child has the potential to learn any human
language.


title:
Mathematical Equivalence vs. Physical Equivalence between Extended
  Theories of Gravitations

abstract:
  We shall show that although Palatini f(R)-theories are equivalent to
Brans-Dicke theories, still the first pass the Mercury precession of perihelia
test, while the second do not. We argue that the two models are not physically
equivalent due to a different assumptions about free fall. We shall also go
through perihelia test without fixing a conformal gauge (clocks or rulers) in
order to highlight what can be measured in a conformal invariant way and what
cannot. We shall argue that the conformal gauge is broken by choosing a
definition of clock, rulers or, equivalently, of masses.


title: Fermion Zero Modes for Abelian BPS Monopoles

abstract:
  Fermion zero modes for abelian BPS monopoles are considered. In the
spherically symmetric case the normalisable zero modes are determined for
arbitrary monopole charge N. If N>1 the zero modes are zero along $N-1$
half-lines emanating from the monopole.


title:
Traits and Characteristics of Interacting Dirac fermions in Monolayer
  and Bilayer Graphene

abstract:
  The relativistic-like behavior of electrons in graphene significantly
influences the interaction properties of these electrons in a quantizing
magnetic field, resulting in more stable fractional quantum Hall effect states
as compared to those in conventional (non-relativistic) semiconductor systems.
In bilayer graphene the interaction strength can be controlled by a bias
voltage and by the orientation of the magnetic field. The finite bias voltage
between the graphene monolayers can in fact, enhance the interaction strength
in a given Landau level. As a function of the bias voltage, a graphene bilayer
system shows transitions from a state with weak electron-electron interactions
to a state with strong interactions. Interestingly, the in-plane component of a
tilted magnetic field can also alter the interaction strength in bilayer
graphene. We also discuss the nature of the Pfaffian state in bilayer graphene
and demonstrate that the stability of this state can be greatly enhanced by
applying an in-plane magnetic field.


title:
Magnetic effects and oversized M dwarfs in the young open cluster NGC
  2516

abstract:
  By combining rotation periods with spectroscopic determinations of projected
rotation velocity, Jackson, Jeffries & Maxted (2009) have found that the mean
radii for low-mass M-dwarfs in the young, open cluster NGC 2516 are larger than
model predictions at a given absolute I magnitude or I - K color and also
larger than measured radii of magnetically inactive M-dwarfs. The relative
radius difference is correlated with magnitude, increasing from a few per cent
at MI = 7 to greater than 50 per cent for the lowest luminosity stars in their
sample at MI about 9.5. Jackson et al (2009) have suggested that a
two-temperature star spot model is capable of explaining the observations, but
their model requires spot coverage fractions of at least 50 per cent in rapidly
rotating M-dwarfs. Here we examine these results in terms of stellar models
that include the inhibiting effects of magnetic fields on convective energy
transport, with and without the effects of star spots. We find that a pure spot
model is inconsistent with the color - magnitude diagram. The observations of
radii versus color and radii versus absolute magnitude in NGC 2516 are
consistent with models which include only magnetic inhibition or a combination
of magnetic inhibition and spots. At a given mass we find a large dispersion in
the strength of the vertical component of the magnetic field in the stellar
photosphere but the general trend is that the vertical field increases with
decreasing mass from a few hundred Gauss at 0.65 Msun to 600 - 900 Gauss,
depending on spot coverage, in the lowest mass stars in the sample at 0.25
Msun.


title:
AGN III - primordial activity in nuclei of late-type galaxies with
  pseudobulges

abstract:
  1. Based on observational data on evolution of quasars and galaxies of
different types along with the results of numerical simulations we make a
conclusion that on low redshifts ($z<0.5$) QSOI/II objects in massive
elliptical and spiral galaxies with classical bulges cannot be in late single
activity event (be "primordial"). Instead of it they have had events of
activity earlier in their evolution. It means that their presence on low
redshifts is connected with the recurrence phenomenon, sequential wet minor
mergings, because timescale of the activity does not exceed several units of
$10^7$ years.
  2. We define a new class - "AGN III" as active galactic nuclei in isolated
late-type spirals with low-mass rapidly rotating pseudobulges. We also state
that only such objects can be in the primordial phase of activity at low
redshifts. Black holes in such galaxies have masses $M_{BH}<10^7M_\odot$ and
also, probably very high spin. Such properties can explain their peculiar
emission spectra.
  A good representative of AGN III might be the galaxies with narrow (${\rm
FWHM}(H\beta)\leq1200$ km/s) broad permitted emission lines - NLS. It is
believed that their black hole masses are less than $M_{BH}<10^7M_\odot$ and
their host galaxies have pseudobulges instead of the classical ones. Because
host galaxies of NLS have pseudobulges and BLS (Broad-Line Seyfert galaxies)
have classical bulges these two types of objects cannot have evolutionary
connection. Presumably, the parent population of NLS are the quasars of
"population A".


title: Effective Conductivities of Thin-Interphase Composites

abstract:
  A method is presented for approximating the effective conductivity of
composite media with thin interphase regions, which is exact to first order in
the interphase thickness. The approximations are computationally efficient in
the sense the fields need to be computed only in a reference composite in which
the interphases have been replaced by perfect interfaces. The results apply
whether any two phases of the composite are separated by a single interphase or
multiple interphases, whether the conductivities of the composite phases are
isotropic or anisotropic, and whether the thickness of an interphase is uniform
or varies as a function of position. It is assumed that the conductivities of
the interphase materials have intermediate values as opposed to very high or
very low conductivities.


title:
Quadratic Chabauty: p-adic height pairings and integral points on
  hyperelliptic curves

abstract:
  We give a formula for the component at p of the p-adic height pairing of a
divisor of degree 0 on a hyperelliptic curve. We use this to give a
Chabauty-like method for finding p-adic approximations to p-integral points on
such curves when the Mordell-Weil rank of the Jacobian equals the genus. In
this case we get an explicit bound for the number of such p-integral points,
and we are able to use the method in explicit computation. An important aspect
of the method is that it only requires a basis of the Mordell-Weil group
tensored with the rationals.


title: Anomalous superfluid density in quantum critical superconductors

abstract:
  When a second-order magnetic phase transition is tuned to zero temperature by
a non-thermal parameter, quantum fluctuations are critically enhanced, often
leading to the emergence of unconventional superconductivity. In these `quantum
critical' superconductors it has been widely reported that the normal-state
properties above the superconducting transition temperature $T_c$ often exhibit
anomalous non-Fermi liquid behaviors and enhanced electron correlations.
However, the effect of these strong critical fluctuations on the
superconducting condensate below $T_c$ is less well established. Here we report
measurements of the magnetic penetration depth in heavy-fermion, iron-pnictide,
and organic superconductors located close to antiferromagnetic quantum critical
points showing that the superfluid density in these nodal superconductors
universally exhibit, unlike the expected $T$-linear dependence, an anomalous
3/2 power-law temperature dependence over a wide temperature range. We propose
that this non-integer power-law can be explained if a strong renormalization of
effective Fermi velocity due to quantum fluctuations occurs only for momenta
$\bm{k}$ close to the nodes in the superconducting energy gap $\Delta(\bm{k})$.
We suggest that such `nodal criticality' may have an impact on low-energy
properties of quantum critical superconductors.


title:
Perturbations and expressions of the Moore--Penrose metric generalized
  inverses and applications to the stability of some operator equations

abstract:
  In this paper, the problems of perturbation and expression for the
Moore--Penrose metric generalized inverses of bounded linear operators on
Banach spaces are further studied. By means of certain geometric assumptions of
Banach spaces, we first give some equivalent conditions for the Moore--Penrose
metric generalized inverse of perturbed operator to have the simplest
expression $T^M(I+ \delta TT^M)^{-1}$. Then, as an application our results, we
investigate the stability of some operator equations in Banach spaces under
different type perturbations.


title:
Topological Bose-Mott Insulators in a One-Dimensional Optical
  Superlattice

abstract:
  We study topological properties of the Bose-Hubbard model with repulsive
interactions in a one-dimensional optical superlattice. We find that the Mott
insulator states of the single-component (two-component) Bose-Hubbard model
under fractional fillings are topological insulators characterized by a nonzero
charge (or spin) Chern number with nontrivial edge states. For ultracold atomic
experiments, we show that the topological Chern number can be detected through
measuring the density profiles of the bosonic atoms in a harmonic trap.


title: On the Redshift of the Very High Energy Blazar 3C 66A

abstract:
  As a bright gamma-ray source, 3C 66A is of great interest to the high-energy
astrophysics community, having a potential for placing cosmological constraints
on models for the extragalactic background light (EBL) and the processes which
contribute to this photon field. No firm spectroscopic redshift measurement has
been possible for this blazar due to a lack of intrinsic emission and
absorption features in optical spectra. We present new far-ultraviolet spectra
from the Hubble Space Telescope/Cosmic Origins Spectrograph (HST/COS) of the BL
Lac object 3C 66A covering the wavelength range 1132 to 1800 Angstroms . The
data show a smooth continuum with intergalactic medium absorption features
which can be used to place a firm lower limit on the blazar redshift of
z>0.3347. An upper limit is set by statistically treating the non-detection of
additional absorbers beyond z=0.3347, indicating a redshift of less than 0.41
at 99% confidence and ruling out z>0.444 at 99.9% confidence. We conclude by
showing how the redshift limits derived from the COS spectra remove the
potential for this gamma-ray emitting blazar to place an upper limit on the
flux of the EBL using high energy data from a flare in October of 2009.


title:
SPINVERT: A program for refinement of paramagnetic diffuse scattering
  data

abstract:
  We present a program (SPINVERT; http://spinvert.chem.ox.ac.uk)for refinement
of magnetic diffuse scattering data for frustrated magnets, spin liquids, spin
glasses, and other magnetically disordered materials. The approach uses reverse
Monte Carlo refinement to fit a large configuration of spins to experimental
powder neutron diffraction data. Despite fitting to spherically-averaged data,
this approach allows the recovery of the three-dimensional magnetic diffuse
scattering pattern and the spin-pair correlation function. We illustrate the
use of the SPINVERT program with two case studies. First we use simulated
powder data for the canonical Heisenberg kagome model to discuss the
sensitivity of SPINVERT refinement to both pairwise and higher-order spin
correlations. The effect of limited experimental data on the results is also
considered. Second, we re-analyse published experimental data on the frustrated
system Y0.5Ca0.5BaCo4O7. The results from SPINVERT refinement indicate
similarities between Y0.5Ca0.5BaCo4O7 and its parent compound YBaCo4O7, which
were overlooked in previous analysis using powder data.


title:
Eigenvalues of congruence covers of geometrically finite hyperbolic
  manifolds

abstract:
  Let G=SO(n,1) and Gamma a geometrically finite Zariski dense subgroup of G
which is contained in an arithmetic subgroup of G. Denoting by Gamma(q) the
principal congruence subgroup of Gamma of level q, and fixing a positive number
\lambda_0 strictly smaller than (n-1)^2/4, we show that, as q tends to infinity
along primes, the number of Laplacian eigenvalues of the congruence cover
Gamma(q)\ H^n smaller than lambda_0 is at most of order [Gamma:Gamma(q)]^c for
some c=c(\lambda_0)>0.


title: A K matrix Construction of Symmetry Enriched Phases of Matter

abstract:
  We construct in the K matrix formalism concrete examples of symmetry enriched
topological phases, namely intrinsically topological phases with global
symmetries. We focus on the Abelian and non-chiral topological phases and
demonstrate by our examples how the interplay between the global symmetry and
the fusion algebra of the anyons of a topologically ordered system determines
the existence of gapless edge modes protected by the symmetry and that a
(quasi)-group structure can be defined among these phases. Our examples include
phases that display charge fractionalization and more exotic non-local anyon
exchange under global symmetry that correspond to general group extensions of
the global symmetry group.


title:
The Mean Value Theorem and Basic Properties of the Obstacle Problem for
  Divergence Form Elliptic Operators

abstract:
  In 1963, Littman, Stampacchia, and Weinberger proved a mean value theorem for
elliptic operators in divergence form with bounded measurable coefficients. In
the Fermi lectures in 1998, Caffarelli stated a much simpler mean value theorem
for the same situation, but did not include the details of the proof. We show
all of the nontrivial details needed to prove the formula stated by Caffarelli,
and in the course of showing these details we establish some of the basic facts
about the obstacle problem for general elliptic divergence form operators, in
particular, we show a basic quadratic nondegeneracy property.


title:
Correlation functions in the prethermalized regime after a quantum
  quench of a spin-chain

abstract:
  Results are presented for a two-point correlation function of a spin-chain
after a quantum quench for an intermediate time regime where inelastic effects
are weak. A Callan-Symanzik like equation for the correlation function is
explicitly constructed which is used to show the appearance of three distinct
scaling regimes. One is for spatial separations within a light-cone, the second
is for spatial separations on the light-cone, and the third is for spatial
separations outside the light-cone. In these three regimes, the correlation
function is found to decay with power-laws with nonequilibrium exponents that
differ from those in equilibrium, as well as from those obtained from quenches
in a quadratic Luttinger liquid theory. A detailed discussion is presented on
how the existence of scaling depends on the properties of the initial state
before the quench.


title:
On the Distribution of the Product and the Sum of Generalized Shifted
  Gamma Random Variables

abstract:
  In general, while obtaining the probability density function of sums and
products of shifted random variables, ordinary analytical methods such as
Fourier and Mellin transforms tend to provide integrals which cannot be
expressed in terms of ordinary Meijer G and H functions. This way, the need of
defining new functions which easily enable one to write such integrals in a
closed-form is inherent to the development of this area of statistical
sciences. By generalizing the Mellin transform which defines the H function, a
new function is established. A direct application of the so-called
$\widehat{I}$ is discussed while developing the probability density function of
the sum and the product of shifted generalized gamma random variables.
Important special cases of the $\widehat{I}$ and their applications in science
are also discussed in order to show the applicability of the function hereby
defined.


title:
The Luminosity function of Narrow-Line Seyfert galaxies based on SDSS
  data

abstract:
  We present measurements of AGN type 1 luminosity function in the forbidden
line [OIII]5007\AA using data from SDSS DR7. A special attention is paid to a
subclass of Seyfert galaxies - the Narrow-Line Seyfert galaxies. These galaxies
have relatively narrow broad permitted emission lines with FWHM $\leq 2000$
km/s. A new approach in calculation of the luminosity function is presented. We
also account for the large-scale structure variations of the Universe density.
The results obtained are compared with the ones from the literature. A
prediction of x-ray luminosity function based on our results shows an agreement
with observations. One of our preliminary conclusions is that NLSy1 seem to
occupy a more narrow range in the nuclear luminosity than BLSy1, but the
average values are within errors.


title:
Spinodal density enhancements in simulations of relativistic nuclear
  collisions

abstract:
  We recently introduced a fluid-dynamical model for simulating relativistic
nuclear collisions in the presence of a first-order phase transition and made
explorative studies of head-on lead-lead collisions. We give here a more
detailed account of this novel theoretical tool and carry out more exhaustive
studies of the phase-separation dynamics. Extracting the density enhancement
caused by the spinodal instabilities, the associated clump size distribution,
and the resulting transverse flow velocity, we examine the sensitivity of these
quantities to the strength of the gradient term that promotes the phase
separation, to the details of the initial density fluctuations that form the
seeds for the subsequent amplification, and to the equation of state.


title:
The extremely low metallicity star SDSS J102915+172927: a subgiant
  scenario

abstract:
  Spectroscopic analysis of the Galactic halo star SDSS J102915+172927 has
shown it to have a very low heavy element abundance, Z < 7.4 10-7, with [Fe/H]
= -4.89 plus/minus 0.10 and an upper limit on the C abundance of [C/H] < -4.5.
The low C/Fe ratio distinguishes this object from most other extremely metal
poor stars. The effective temperature and surface gravity have been determined
to be Teff = 5811 plus/minus 150 K and log g = 4.0 plus/minus 0.5. The surface
gravity estimate is problematical in that it places the star between the main
sequence and the subgiants in the Hertzsprung-Russell diagram. If it is assumed
that the star is on the main sequence, its mass and are estimated to be M =
0.72 plus/minus 0.06 Msun and L = 0.45 plus/minus 0.10 Lsun, placing it at a
distance of 1.35 plus/minus 0.16 kpc. The upper limit on the lithium abundance,
A(Li) < 0.9, is inconsistent with the star being a dwarf, assuming that mixing
is due only to convection. In this paper, we propose that SJ102915 is a
sub-giant that formed with significantly higher Z than currently observed, in
agreement with theoretical predictions for the minimum C and/or O abundances
needed for low mass star formation. In this scenario, extremely low Z and low
Li abundance result from gravitational settling on the main sequence followed
by incomplete convective dredge-up during subgiant evolution. The observed Fe
abundance requires the initial Fe abundance to be enhanced compared to C and O,
which we interpret as formation of SJ102915 occurring in the vicinity of a type
Ia supernova.


title:
Hybrids of a Genetically Engineered Antibody and a Carbon Nanotube
  Transistor for Detection of Prostate Cancer Biomarkers

abstract:
  We developed a novel detection method for osteopontin (OPN), a new biomarker
for prostate cancer, by attaching a genetically engineered single chain
variable fragment (scFv) protein with high binding affinity for OPN to a carbon
nanotube field-effect transistor (NTFET). Chemical functionalization using
diazonium salts is used to covalently attach scFv to NT-FETs, as confirmed by
atomic force microscopy, while preserving the activity of the biological
binding site for OPN. Electron transport measurements indicate that
functionalized NT-FET may be used to detect the binding of OPN to the
complementary scFv protein. A concentration-dependent increase in the
source-drain current is observed in the regime of clinical significance, with a
detection limit of approximately 30 fM. The scFv-NT hybrid devices exhibit
selectivity for OPN over other control proteins. These devices respond to the
presence of OPN in a background of concentrated bovine serum albumin, without
loss of signal. Based on these observations, the detection mechanism is
attributed to changes in scattering at scFv protein-occupied defect sites on
the carbon nanotube sidewall. The functionalization procedure described here is
expected to be generalizable to any antibody containing an accessible amine
group, and to result in biosensors appropriate for detection of corresponding
complementary proteins at fM concentrations.


title: A Carbon Nanotube Immunosensor for Salmonella

abstract:
  Antibody-functionalized carbon nanotube devices have been suggested for use
as bacterial detectors for monitoring of food purity in transit from the farm
to the kitchen. Here we report progress towards that goal by demonstrating
specific detection of Salmonella in complex nutrient broth solutions using
nanotube transistors functionalized with covalently-bound anti-Salmonella
antibodies. The small size of the active device region makes them compatible
with integration in large-scale arrays. We find that the on-state current of
the transistor is sensitive specifically to the Salmonella concentration and
saturates at low concentration (<1000 cfu/ml). In contrast, the carrier
mobility is affected comparably by Salmonella and other bacteria types, with no
sign of saturation even at much larger concentrations (10^8 cfu/ml).


title:
Towards Quantifying the electrostatic transduction mechanism in carbon
  nanotube molecular sensors

abstract:
  Despite the great promise of carbon nanotube field effect transistors (CNT
FETs) for applications in chemical and biochemical detection, a quantitative
understanding of sensor responses is lacking. To explore the role of
electrostatics in sensor transduction, experiments were conducted with a set of
highly similar compounds designed to adsorb onto the CNT FET via a pyrene
linker group and take on a set of known charge states under ambient conditions.
Acidic and basic species were observed to induce threshold voltage shifts of
opposite sign, consistent with gating of the CNT FET by local charges due to
protonation or deprotonation of pyrene compounds by interfacial water. The
magnitude of the gate voltage shift was controlled by the distance between the
charged group and the CNT. Additionally, functionalization with an un-charged
pyrene compound showed a threshold shift ascribed to its molecular dipole
moment. This work illustrates a method to produce CNT FETs with controlled
values of the turnoff gate voltage, and more generally, these results will
inform the development of quantitative models for the response of CNT FET
chemical and biochemical sensors.


title:
Detecting Lyme Disease Using Antibody-Functionalized Single-Walled
  Carbon Nanotube Transistors

abstract:
  We examined the potential of antibody-functionalized single-walled carbon
nanotube (SWNT) field-effect transistors (FETs) for use as a fast and accurate
sensor for a Lyme disease antigen. Biosensors were fabricated on oxidized
silicon wafers using chemical vapor deposition grown carbon nanotubes that were
functionalized using diazonium salts. Attachment of Borrelia burgdorferi (Lyme)
flagellar antibodies to the nanotubes was verified by Atomic Force Microscopy
and electronic measurements. A reproducible shift in the turn-off voltage of
the semiconducting SWNT FETs was seen upon incubation with Borrelia burgdorferi
flagellar antigen, indicative of the nanotube FET being locally gated by the
residues of flagellar protein bound to the antibody. This sensor effectively
detected antigen in buffer at concentrations as low as 1 ng/ml, and the
response varied strongly over a concentration range coinciding with levels of
clinical interest. Generalizable binding chemistry gives this biosensing
platform the potential to be expanded to monitor other relevant antigens,
enabling a multiple vector sensor for Lyme disease. The speed and sensitivity
of this biosensor make it an ideal candidate for development as a medical
diagnostic test.


title:
Self-assembled ErSb nanostructures of tunable shape and orientation:
  growth and plasmonic properties

abstract:
  Self-assembled, semimetallic ErSb single crystal nanostructures, grown by
molecular beam epitaxy, are embedded within a semiconductor GaSb matrix.
Formation, evolution and orientation of a variety of nanostructures, including
spherical nanoparticles, elongated nanorods, octagonal shaped nanowires
oriented along the surface normal and nanowires oriented in the growth plane,
are controlled simply by the Er fraction. The plasmonic properties of the
semimetal/semiconductor composites are characterized and quantified by three
polarization-resolved spectroscopy techniques, spanning more than three orders
of magnitude in frequency from 100 GHz up to 300 THz. The effect of the size,
shape and orientation of the nanostructures is characterized by
polarization-sensitive response and modeled by a Maxwell-Garnett effective
medium theory.


title:
Geant4 Applications for Modeling Molecular Transport in Complex Vacuum
  Geometries

abstract:
  We discuss a novel use of the Geant4 simulation toolkit to model molecular
transport in a vacuum environment, in the molecular flow regime. The Geant4
toolkit was originally developed by the high energy physics community to
simulate the interactions of elementary particles within complex detector
systems. Here its capabilities are utilized to model molecular vacuum transport
in geometries where other techniques are impractical. The techniques are
verified with an application representing a simple vacuum geometry that has
been studied previously both analytically and by basic Monte Carlo simulation.
We discuss the use of an application with a very complicated geometry, that of
the Large Synoptic Survey Telescope camera cryostat, to determine probabilities
of transport of contaminant molecules to optical surfaces where control of
contamination is crucial.


title:
s+is State with Broken Time Reversal Symmetry in Fe-Based
  Superconductors

abstract:
  We analyze the evolution of the superconducting gap structure in strongly
hole doped Ba_{1-x}K_xFe_2As_2 between x=1 and x ~ 0.4 (optimal doping). In the
latter case, the pairing state is most likely s+-, with different gap signs on
hole and electron pockets, but with the same signs of the gap on the two
Gamma-centered hole pockets (a ++ state on hole pockets). In a pure KFe_2As_2
(x=1), which has only hole pockets, laser ARPES data suggested another s+-
state, in which the gap changes sign between hole pockets (a +- state). We
analyze how ++ gap transforms into a +- gap as x -> 1. We found that this
transformation occurs via an intermediate s+is, state in which the gaps on the
two hole pockets differ in phase by `phi', which gradually involves from `phi'
= pi (the +- state) to phi =0 (the ++ state). This state breaks time-reversal
symmetry and has huge potential for applications. We compute the dispersion of
collective excitations and show that two different Leggett-type phase modes
soften at the two end points of TRSB state.


title: Thermal Hyperbolic Metamaterials

abstract:
  We explore the near-field radiative thermal energy transfer properties of
hyperbolic metamaterials. The presence of unique electromagnetic states in a
broad bandwidth leads to super-planckian thermal energy transfer between
metamaterials separated by a nano-gap. We consider practical phonon-polaritonic
metamaterials for thermal engineering in the mid-infrared range and show that
the effect exists in spite of the losses, absorption and finite unit cell size.
For thermophotovoltaic energy conversion applications requiring energy transfer
in the near-infrared range we introduce high temperature hyperbolic
metamaterials based on plasmonic materials with a high melting point. Our work
paves the way for practical high temperature radiative thermal energy transfer
applications of hyperbolic metamaterials.


title: The Family of MapReduce and Large Scale Data Processing Systems

abstract:
  In the last two decades, the continuous increase of computational power has
produced an overwhelming flow of data which has called for a paradigm shift in
the computing architecture and large scale data processing mechanisms.
MapReduce is a simple and powerful programming model that enables easy
development of scalable parallel applications to process vast amounts of data
on large clusters of commodity machines. It isolates the application from the
details of running a distributed program such as issues on data distribution,
scheduling and fault tolerance. However, the original implementation of the
MapReduce framework had some limitations that have been tackled by many
research efforts in several followup works after its introduction. This article
provides a comprehensive survey for a family of approaches and mechanisms of
large scale data processing mechanisms that have been implemented based on the
original idea of the MapReduce framework and are currently gaining a lot of
momentum in both research and industrial communities. We also cover a set of
introduced systems that have been implemented to provide declarative
programming interfaces on top of the MapReduce framework. In addition, we
review several large scale data processing systems that resemble some of the
ideas of the MapReduce framework for different purposes and application
scenarios. Finally, we discuss some of the future research directions for
implementing the next generation of MapReduce-like solutions.


title: Possible Evidence of Thermodynamic Equilibrium in Dark Matter Haloes

abstract:
  After deducing the density profiles and gravitational potential functions of
eight galaxies from the rotation velocity data from THINGS, we find that the
density decreases exponentially with the potential in substantial regions of
the haloes. Such behavior is in agreement with that of a single-component
isothermal Boltzmann gas, and suggests that an effective description in terms
of a Boltzmann gas is possible for dark matter in these regions. This could be
an indication that dark matter self-interactions are sufficient in strength and
number to lead to thermal equilibrium in these regions. We write down the
dynamics and boundary conditions for a Boltzmann gas description and examine
some of its qualitative and quantitative consequences. Solutions to the
dynamical system are determined by three dimensionfull parameters, and provide
reasonable fits to the rotational velocity data in the regions where the
Boltzmann-like behavior was found. Unlike in the usual approach to curve
fitting, we do not assume a specific form for the dark matter density profile
and we do not require a detailed knowledge of the baryonic content of the
galaxy.


title:
Particle dynamics in two-dimensional random energy landscapes -
  experiments and simulations

abstract:
  The dynamics of individual colloidal particles in random potential energy
landscapes were investigated experimentally and by Monte Carlo simulations. The
value of the potential at each point in the two-dimensional energy landscape
follows a Gaussian distribution. The width of the distribution, and hence the
degree of roughness of the energy landscape, was varied and its effect on the
particle dynamics studied. This situation represents an example of Brownian
dynamics in the presence of disorder. In the experiments, the energy landscapes
were generated optically using a holographic set-up with a spatial light
modulator, and the particle trajectories were followed by video microscopy. The
dynamics are characterized using, e.g., the time-dependent diffusion
coefficient, the mean squared displacement, the van Hove function and the
non-Gaussian parameter. In both, experiments and simulations, the dynamics are
initially diffusive, show an extended sub-diffusive regime at intermediate
times before diffusive motion is recovered at very long times. The dependence
of the long-time diffusion coefficient on the width of the Gaussian
distribution agrees with theoretical predictions. Compared to the dynamics in a
one-dimensional potential energy landscape, the localization at intermediate
times is weaker and the diffusive regime at long times reached earlier, which
is due to the possibility to avoid local maxima in two-dimensional energy
landscapes.


title:
Towards Identification of Relevant Variables in the observed Aerosol
  Optical Depth Bias between MODIS and AERONET observations

abstract:
  Measurements made by satellite remote sensing, Moderate Resolution Imaging
Spectroradiometer (MODIS), and globally distributed Aerosol Robotic Network
(AERONET) are compared. Comparison of the two datasets measurements for aerosol
optical depth values show that there are biases between the two data products.
In this paper, we present a general framework towards identifying relevant set
of variables responsible for the observed bias. We present a general framework
to identify the possible factors influencing the bias, which might be
associated with the measurement conditions such as the solar and sensor zenith
angles, the solar and sensor azimuth, scattering angles, and surface
reflectivity at the various measured wavelengths, etc. Specifically, we
performed analysis for remote sensing Aqua-Land data set, and used machine
learning technique, neural network in this case, to perform multivariate
regression between the ground-truth and the training data sets. Finally, we
used mutual information between the observed and the predicted values as the
measure of similarity to identify the most relevant set of variables. The
search is brute force method as we have to consider all possible combinations.
The computations involves a huge number crunching exercise, and we implemented
it by writing a job-parallel program.


title:
Velocity selective trapping of atoms in a frequency-modulated standing
  laser wave

abstract:
  The wave function of a moderately cold atom in a stationary near-resonant
standing light wave delocalizes very fast due to wave packet splitting.
However, we show that frequency modulation of the field may suppress packet
splitting for some atoms having specific velocities in a narrow range. These
atoms remain localized in a small space for a long time. We propose that in a
real experiment with cold atomic gas this effect may decrease the velocity
distribution of atoms (the field traps the atoms with such specific velocities
while all other atoms leave the field)


title:
A Local Limit Theorem and Loss of Rotational Symmetry of Planar
  Symmetric Simple Random Walk

abstract:
  We derive a local limit theorem for normal, moderate, and large deviations
for symmetric simple random walk on the square lattice in dimensions one and
two that is an improvement of existing results for points that are particularly
distant from the walk's starting point. More specifically, we give explicit
asymptotic expressions in terms of $n$ and $x$, where $x$ is thought of as
dependent on $n$, in dimensions one and two for $P(S_n=x)$, the probability
that symmetric simple random walk $S$ started at the origin is at some point
$x$ at time $n$, that are valid for all $x$. We also show that the behavior of
planar symmetric simple random walk differs radically from that of planar
standard Brownian motion outside of the disk of radius $n^{3/4}$, where the
random walk ceases to be approximately rotationally symmetric. Indeed, if
$n^{3/4}=o(|S_n|)$, $S_n$ is more likely to be found along the coordinate axes.
In this paper, we give a description of how the transition from approximate
rotational symmetry to complete concentration of $S$ along the coordinate axes
occurs.


title:
Discrete Schlesinger Transformations, their Hamiltonian Formulation, and
  Difference Painlev\'e Equations

abstract:
  Schlesinger transformations are algebraic transformations of a Fuchsian
system that preserve its monodromy representation and act on the characteristic
indices of the system by integral shifts. One of the important reasons to study
such transformations is the relationship between Schlesinger transformations
and discrete Painlev\'e equations; this is also the main theme behind our work.
We derive \emph{discrete Schlesinger evolution equations} describing discrete
dynamical systems generated by elementary Schlesinger transformations and give
their discrete Hamiltonian description w.r.t.~the standard symplectic structure
on the space of Fuchsian systems. As an application, we compute explicitly two
examples of reduction from Schlesinger transformations to difference Painlev\'e
equations. The first example, d-$P\big(D_{4}^{(1)}\big)$ (or difference
Painlev\'e V), corresponds to B\"acklund transformations for continuous
$P_{\text{VI}}$. The second example, d-$P\big(A_{2}^{(1)*}\big)$ (with the
symmetry group $E_{6}^{(1)}$), is purely discrete. We also describe the role
played by the geometry of the Okamoto space of initial conditions in comparing
different equations of the same type.


title: Combinatorics of Matrix Factorizations and Integrable Systems

abstract:
  We study relations between the eigenvectors of rational matrix functions on
the Riemann sphere. Our main result is that for a subclass of functions that
are products of two elementary blocks it is possible to represent these
relations in a combinatorial-geometric way using a diagram of a cube. In this
representation, vertices of the cube represent eigenvectors, edges are labeled
by differences of locations of zeroes and poles of the determinant of our
matrix function, and each face corresponds to a particular choice of a
coordinate system on the space of such functions. Moreover, for each face this
labeling encodes, in a neat and efficient way, a generating function for the
expressions of the remaining four eigenvectors that label the opposing face of
the cube in terms of the coordinates represented by the chosen face. The main
motivation behind this work is that when our matrix is a Lax matrix of a
discrete integrable system, such generating functions can be interpreted as
Lagrangians of the system, and a choice of a particular face corresponds to a
choice of the direction of the motion.


title:
Four Decades of Computing in Subnuclear Physics - from Bubble Chamber to
  LHC

abstract:
  This manuscript addresses selected aspects of computing for the
reconstruction and simulation of particle interactions in subnuclear physics.
Based on personal experience with experiments at DESY and at CERN, I cover the
evolution of computing hardware and software from the era of track chambers
where interactions were recorded on photographic film up to the LHC experiments
with their multi-million electronic channels.