title: Electronic exchange in quantum rings

abstract:
  Quantum rings can be characterized by a specific radius and ring width. For
this rich class of physical systems, an accurate approximation for the
exchange-hole potential and thus for the exchange energy is derived from first
principles. Excellent agreement with the exact-exchange results is obtained
regardless of the ring parameters, total spin, current, or the external
magnetic field. The description can be applied as a density functional
outperforming the commonly used local-spin-density approximation, which is here
explicitly shown to break down in the quasi-one-dimensional limit. The
dimensional crossover, which is of extraordinary importance in low-dimensional
systems, is fully captured by our functional.


title: Number of natively unfolded proteins scales with genome size

abstract:
  Natively unfolded proteins exist as an ensemble of flexible conformations
lacking a well defined tertiary structure along a large portion of their
polypeptide chain. Despite the absence of a stable configuration, they are
involved in important cellular processes. In this work we used from three
indicators of folding status, derived from the analysis of mean packing and
mean contact energy of a protein sequence as well as from VSL2, a disorder
predictor, and we combined them into a consensus score to identify natively
unfolded proteins in several genomes from Archaea, Bacteria and Eukarya. We
found a high correlation among the number of predicted natively unfolded
proteins and the number of proteins in the genomes. More specifically, the
number of natively unfolded proteins scaled with the number of proteins in the
genomes, with exponent 1.81 +- 0.10. This scaling law may be important to
understand the relation between the number of natively unfolded proteins and
their roles in cellular processes.


title: Phase Transitions and Chaos in Long-Range Models of Coupled Oscillators

abstract:
  We study the chaotic behavior of the synchronization phase transition in the
Kuramoto model. We discuss the relationship with analogous features found in
the Hamiltonian Mean Field (HMF) model. Our numerical results support the
connection between the two models, which can be considered as limiting cases
(dissipative and conservative, respectively) of a more general dynamical system
of damped-driven coupled pendula. We also show that, in the Kuramoto model, the
shape of the phase transition and the largest Lyapunov exponent behavior are
strongly dependent on the distribution of the natural frequencies.

categories: cond-mat.stat-mech astro-ph nlin.CD nucl-th physics.class-ph physics.plasm-ph


title:
Characterization of the reactive flow field dynamics in a gas turbine
  injector using high frequency PIV

abstract:
  The present work details the analysis of the aerodynamics of an experimental
swirl stabilized burner representative of gas turbine combustors. This analysis
is carried out using High Frequency PIV (HFPIV) measurements in a reactive
situation. While this information is usually available at a rather low rate,
temporally resolved PIV measurements are necessary to better understand highly
turbulent swirled flows, which are unsteady by nature. Thanks to recent
technical improvements, a PIV system working at 12 kHz has been developed to
study this experimental combustor flow field. Statistical quantities of the
burner are first obtained and analyzed, and the measurement quality is checked,
then a temporal analysis of the velocity field is carried out, indicating that
large coherent structures periodically appear in the combustion chamber. The
frequency of these structures is very close to the quarter wave mode of the
chamber, giving a possible explanation for combustion instability coupling.


title: Brown representability does not come for free

abstract:
  We exhibit a triangulated category T having both products and coproducts, and
a triangulated subcategory S of T which is both localizing and colocalizing,
for which neither a Bousfield localization nor a colocalization exists. It
follows that neither the category S nor its dual satisfy Brown
representability. Our example involves an abelian category whose derived
category does not have small Hom-sets.


title:
Turbulence energetics in stably stratified geophysical flows: strong and
  weak mixing regimes

abstract:
  Traditionally, turbulence energetics is characterized by turbulent kinetic
energy (TKE) and modelled using solely the TKE budget equation. In stable
stratification, TKE is generated by the velocity shear and expended through
viscous dissipation and work against buoyancy forces. The effect of
stratification is characterized by the ratio of the buoyancy gradient to
squared shear, called Richardson number, Ri. It is widely believed that at Ri
exceeding a critical value, Ric, local shear cannot maintain turbulence, and
the flow becomes laminar. We revise this concept by extending the energy
analysis to turbulent potential and total energies (TPE and TTE = TKE + TPE),
consider their budget equations, and conclude that TTE is a conservative
parameter maintained by shear in any stratification. Hence there is no
"energetics Ric", in contrast to the hydrodynamic-instability threshold,
Ric-instability, whose typical values vary from 0.25 to 1. We demonstrate that
this interval, 0.25<Ri<1, separates two different turbulent regimes: strong
mixing and weak mixing rather than the turbulent and the laminar regimes, as
the classical concept states. This explains persistent occurrence of turbulence
in the free atmosphere and deep ocean at Ri>>1, clarify principal difference
between turbulent boundary layers and free flows, and provide basis for
improving operational turbulence closure models.

categories: physics.ao-ph astro-ph.EP nlin.CD physics.flu-dyn


title: Approaching the thermodynamic limit in equilibrated scale-free networks

abstract:
  We discuss how various models of scale-free complex networks approach their
limiting properties when the size N of the network grows. We focus mainly on
equilibrated networks and their finite-size degree distributions. Our results
show that subleading corrections to the scaling of the position of the cutoff
are strong even for networks of order 10^9 nodes. We observe also a logarithmic
correction to the scaling for degenerated graphs when the degree distribution
follows a power law k^(-3). We study also the distribution of the maximal
degree and show that it may have a different scaling than the cutoff and,
moreover, it approaches the thermodynamic limit much faster. We present also
some results on the cutoff function and the distribution of the maximal degree
in equilibrated networks.


title: The cluster glass state in the two-dimensional extended t-J model

abstract:
  The recent observation of an electronic cluster glass state composed of
random domains with unidirectional modulation of charge density and/or spin
density on Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta} reinvigorates the debate of
existence of competing interactions and their importance in high temperature
superconductivity. By using a variational approach, here we show that the
presence of the cluster glass state is actually an inherent nature of the model
based on the antiferromagnetic interaction (J) only, i.e. the well known t-J
model. There is no need yet to introduce a competing interaction to understand
the existence of the cluster glass state. The long-range pairing correlation is
not much influenced by the disorder in the glass state which also has nodes and
linear density of states. In the antinodal region, the spectral weight is
almost completely suppressed. The modulation also produces subgap structures
inside the "coherent" peaks of the local density of states.


title: Teichmuller geometry of moduli space, II: M(S) seen from far away

abstract:
  We construct a metric simplicial complex which is an almost isometric model
of the moduli space M(S) of Riemann surfaces. We then use this model to compute
the "tangent cone at infinity" of M(S): it is the topological cone on the
quotient of the complex of curves C(S) by the mapping class group of S, endowed
with an explicitly described metric. The main ingredient is Minsky's product
regions theorem.


title: Nonlinear Schrodinger-Pauli Equations

abstract:
  We obtain novel nonlinear Schr\"{o}dinger-Pauli equations through a formal
non-relativistic limit of appropriately constructed nonlinear Dirac equations.
This procedure automatically provides a physical regularisation of potential
singularities brought forward by the nonlinear terms and suggests how to
regularise previous equations studied in the literature. The enhancement of
contributions coming from the regularised singularities suggests that the
obtained equations might be useful for future precision tests of quantum
nonlinearity.


title: On asymptotic stability of solitons for nonlinear Sch\"odinger equation

abstract:
  The long-time asymptotics is analyzed for finite energy solutions of the 1D
Schr\"odinger equation coupled to a nonlinear oscillator; mathematically the
system under study is a nonlinear Schr\"odinger equation, whose nonlinear term
includes a Dirac delta. The coupled system is invariant with respect to the
phase rotation group U(1). This article, which extends the results of a
previous one, provides a proof of asymptotic stability of solitary wave
solutions in the case that the linearization contains a single discrete
oscillatory mode satisfying a non-degeneracy assumption of the type known as
the Fermi Golden Rule.


title: Measuring co-authorship and networking-adjusted scientific impact

abstract:
  Appraisal of the scientific impact of researchers, teams and institutions
with productivity and citation metrics has major repercussions. Funding and
promotion of individuals and survival of teams and institutions depend on
publications and citations. In this competitive environment, the number of
authors per paper is increasing and apparently some co-authors don't satisfy
authorship criteria. Listing of individual contributions is still sporadic and
also open to manipulation. Metrics are needed to measure the networking
intensity for a single scientist or group of scientists accounting for patterns
of co-authorship. Here, I define I1 for a single scientist as the number of
authors who appear in at least I1 papers of the specific scientist. For a group
of scientists or institution, In is defined as the number of authors who appear
in at least In papers that bear the affiliation of the group or institution. I1
depends on the number of papers authored Np. The power exponent R of the
relationship between I1 and Np categorizes scientists as solitary (R>2.5),
nuclear (R=2.25-2.5), networked (R=2-2.25), extensively networked (R=1.75-2) or
collaborators (R<1.75). R may be used to adjust for co-authorship networking
the citation impact of a scientist. In similarly provides a simple measure of
the effective networking size to adjust the citation impact of groups or
institutions. Empirical data are provided for single scientists and
institutions for the proposed metrics. Cautious adoption of adjustments for
co-authorship and networking in scientific appraisals may offer incentives for
more accountable co-authorship behaviour in published articles.


title: Inflation-Dark Energy unified through Quantum Regeneration

abstract:
  We study a scalar phi field that unifies inflation and dark energy with a
long period of a hot decelerating universe in between these two stages of
inflation. A key feature is that the transition between the intermediate
decelerated phase to the dark energy phase is related to a quantum regeneration
of the scalar field phi instead to purely classical dynamics. The interaction
V_int(phi,varphi) between phi and a second scalar field varphi allows not only
for phi to decay at a high energy E_I, even though phi does not oscillate
around the minimum of its potential, but it also regenerates phi at an energy
E_{BD} \simeq E_I^2 close to present time. It predicts extra relativistic
energy and an interacting dark energy which may account for a w<-1. In the
model presented here we have E_I \simeq 100 TeV and E_{BD} \simeq 1 eV. The low
value of the back decay energy E_{BD} gives an explanation of the coincidence
problem.


title: Time-resolved detection of single-electron interference

abstract:
  We demonstrate real-time detection of self-interfering electrons in a double
quantum dot embedded in an Aharonov-Bohm interferometer, with visibility
approaching unity. We use a quantum point contact as a charge detector to
perform time-resolved measurements of single-electron tunneling. With increased
bias voltage, the quantum point contact exerts a back-action on the
interferometer leading to decoherence. We attribute this to emission of
radiation from the quantum point contact, which drives non-coherent electronic
transitions in the quantum dots.


title:
Long-distance frequency transfer over an urban fiber link using optical
  phase stabilization

abstract:
  We transferred the frequency of an ultra-stable laser over 86 km of urban
fiber. The link is composed of two cascaded 43-km fibers connecting two
laboratories, LNE-SYRTE and LPL in Paris area. In an effort to realistically
demonstrate a link of 172 km without using spooled fiber extensions, we
implemented a recirculation loop to double the length of the urban fiber link.
The link is fed with a 1542-nm cavity stabilized fiber laser having a sub-Hz
linewidth. The fiber-induced phase noise is measured and cancelled with an all
fiber-based interferometer using commercial off the shelf pigtailed
telecommunication components. The compensated link shows an Allan deviation of
a few 10-16 at one second and a few 10-19 at 10,000 seconds.


title: Granular Solid Hydrodynamics

abstract:
  Granular elasticity, an elasticity theory useful for calculating static
stress distribution in granular media, is generalized to the dynamic case by
including the plastic contribution of the strain. A complete hydrodynamic
theory is derived based on the hypothesis that granular medium turns
transiently elastic when deformed. This theory includes both the true and the
granular temperatures, and employs a free energy expression that encapsulates a
full jamming phase diagram, in the space spanned by pressure, shear stress,
density and granular temperature. For the special case of stationary granular
temperatures, the derived hydrodynamic theory reduces to {\em hypoplasticity},
a state-of-the-art engineering model.


title: Hamiltonian Cosmology

abstract:
  The cosmological scale factor $a(t)$ of the flat-space Robertson-Walker
geometry is examined from a Hamiltonian perspective wherein $a(t)$ is
interpreted as an independent dynamical coordinate and the curvature density
$\sqrt {- g(a)} R({a,\dot a,\ddot a})$ is regarded as an action density in
Minkowski spacetime. The resulting Hamiltonian for $a(t)$ is just the first
Friedmann equation of the traditional approach (i.e. the Robertson-Walker
cosmology of General Relativity), as might be expected. The utility of this
approach however stems from the fact that each of the terms matter, radiation,
and vacuum, and including the kinetic / gravitational field term, are formally
energy densities, and the equation as a whole becomes a formal statement of
energy conservation. An advantage of this approach is that it facilitates an
intuitive understanding of energy balance and exchange on the cosmological
scale that is otherwise absent in the traditional presentation. Each coordinate
system has its own internally consistent explanation for how energy balance is
achieved. For example, in the spacetime with line element $ds^2 = dt^2 - a^2(t)
d{\bf{x}}^2$, cosmological red-shift emerges as due to a post-recombination
interaction between the scalar field $a(t)$ and the EM fields in which the
latter loose energy as if propagating through a homogeneous lossy medium, with
the energy lost to the scale factor helping drive the cosmological expansion.


title: Evaporation of extrasolar planets

abstract:
  Atomic hydrogen escaping from the extrasolar giant planet HD209458b provides
the largest observational signature ever detected for an extrasolar planet
atmosphere. In fact, the upper atmosphere of this planet is evaporating.
Observational evidences and interpretations coming from various models are
reviewed. Implications for exoplanetology are discussed.


title:
Crystallization of trions in SU(3) cold atom gases trapped in optical
  lattices

abstract:
  Cold Fermionic atoms with three different hyperfine states confined in
optical lattices show pronounced Atomic Density Waves (ADWs). These ADWs are
pinned due to the confining potential that traps the atoms in the optical
lattice and can be considered a crystal of strongly bound trions. We show that
the crystalline phase is incompressible and robust against SU(3) symmetry
breaking interaction. We also show that it is generic in the presence of the
trap due to its incompressible characteristics. A simulation of the time
evolution of the fermionic gas after the trapping potential is switch off shows
that the formation of the trionic crystal is marked by a freezing of the
dynamics in the lattice.


title:
Experimental and Theoretical Study on 2D Ordered and 3D Disordered
  SIS-type Arrays of Josephson Junctions

abstract:
  By employing mutual-inductance technique and using a high-sensitive bridge,
we have thoroughly investigated (both experimentally and theoretically) the
temperature and magnetic field dependence of complex AC susceptibility of
artificially prepared highly ordered (periodic) two-dimensional Josephson
junction arrays (2D-JJA) of both shunted and unshunted Nb-based tunnel
junctions as well as disordered three-dimensional arrays (3D-JJA). This paper
reviews some of our latest results regarding the influence of non-uniform
critical current density profile on magnetic field behavior of AC
susceptibility in 2D-JJA, and the origin of remanent magnetization in
disordered 3D-JJAs.


title:
Minimal Agent Based Model For The Origin And Self-Organization Of
  Stylized Facts In Financial Markets

abstract:
  We introduce a minimal Agent Based Model with two classes of agents,
fundamentalists (stabilizing) and chartists (destabilizing) and we focus on the
essential features which can generate the stylized facts. This leads to a
detailed understanding of the origin of fat tails and volatility clustering and
we propose a mechanism for the self-organization of the market dynamics in the
quasi-critical state. The stylized facts are shown to correspond to finite size
effects which, however, can be active at different time scales. This implies
that universality cannot be expected in describing these properties in terms of
effective critical exponents. The introduction of a threshold in the agents'
action (small price fluctuations lead to no-action) triggers the
self-organization towards the quasi-critical state. Non-stationarity in the
number of active agents and in their action plays a fundamental role. The model
can be easily generalized to more realistic variants in a systematic way.


title:
Scattering Amplitudes, Wilson Loops and the String/Gauge Theory
  Correspondence

abstract:
  We review, in a self-contained and pedagogical manner, recent developments
and techniques for the evaluation of the scattering amplitudes of planar N=4
SYM theory at both weak and strong coupling. Special emphasis is placed on the
newly discovered connection between a special class of amplitudes and the
expectation values of particular cusped light-like Wilson loops.


title:
The DEEP2 Redshift Survey: Lyman Alpha Emitters in the Spectroscopic
  Database

abstract:
  We present the first results of a search for Lyman-alpha emitters (LAEs) in
the DEEP2 spectroscopic database that uses a search technique that is different
from but complementary to traditional narrowband imaging surveys. We have
visually inspected ~20% of the available DEEP2 spectroscopic data and have
found nine high-quality LAEs with clearly asymmetric line profiles and an
additional ten objects of lower quality, some of which may also be LAEs. Our
survey is most sensitive to LAEs at z=4.4-4.9 and that is indeed where all but
one of our high-quality objects are found. We find the number density of our
spectroscopically-discovered LAEs to be consistent with those found in
narrowband imaging searches. The combined, averaged spectrum of our nine
high-quality objects is well fit by a two-component model, with a second,
lower-amplitude component redshifted by ~420 km/s with respect to the primary
Lyman-alpha line, consistent with large-scale outflows from these objects. We
conclude by discussing the advantages and future prospects of blank-sky
spectroscopic surveys for high-z LAEs.


title: Online Scheduling to Minimize the Maximum Delay Factor

abstract:
  In this paper two scheduling models are addressed. First is the standard
model (unicast) where requests (or jobs) are independent. The other is the
broadcast model where broadcasting a page can satisfy multiple outstanding
requests for that page. We consider online scheduling of requests when they
have deadlines. Unlike previous models, which mainly consider the objective of
maximizing throughput while respecting deadlines, here we focus on scheduling
all the given requests with the goal of minimizing the maximum {\em delay
factor}.We prove strong lower bounds on the achievable competitive ratios for
delay factor scheduling even with unit-time requests.For the unicast model we
give algorithms that are $(1 + \eps)$-speed $O({1 \over \eps})$-competitive in
both the single machine and multiple machine settings. In the broadcast model
we give an algorithm for similar-sized pages that is $(2+ \eps)$-speed $O({1
\over \eps^2})$-competitive. For arbitrary page sizes we give an algorithm that
is $(4+\eps)$-speed $O({1 \over \eps^2})$-competitive.


title: On quasiinvariants of $S_n$ of hook shape

abstract:
  Chalykh, Veselov and Feigin introduced the notions of quasiinvariants for
Coxeter groups, which is a generalization of invariants. In [2], Bandlow and
Musiker showed that for the symmetric group $S_n$ of order $n$, the space of
quasiinvariants has a decomposition indexed by standard tableaux. They gave a
description of basis for the components indexed by standard tableaux of shape
$(n-1,1)$. In this paper, we generalize their results to a description of basis
for the components indexed by standard tableaux of arbitrary hook shape.


title:
Bogoliubov Angle, Particle-Hole Mixture and Angular Resolved
  Photoemission Spectroscopy in Superconductors

abstract:
  Superconducting excitations -- Bogoliubov quasiparticles -- are the quantum
mechanical mixture of negatively charged electron (-e) and positively charged
hole (+e). We propose a new observable for Angular Resolved Photoemission
Spectroscopy (ARPES) studies that is the manifestation of the particle-hole
entanglement of the superconducting quasiparticles. We call this observable a
{\em Bogoliubov angle}. This angle measures the relative weight of particle and
hole amplitude in the superconducting (Bogoliubov) quasiparticle. We show how
this quantity can be measured by comparing the ratio of spectral intensities at
positive and negative energies.


title:
Temperature effects on magnetoplasmon spectrum of a weakly modulated
  graphene monolayer

abstract:
  In this work, we determine the effects of temperature on the magnetoplasmon
spectrum of an electrically modulated graphene monolayer as well as the
two-dimensional electron gas (2DEG). The intra-Landau-band magnetoplasmon
spectrum within the Self Consistent Field (SCF) approach is investigated for
both the aforementioned systems. Results obtained not only exhibit Shubnikov-de
Hass (SdH) oscillations but also commensurability oscillations (Weiss
oscillations). These oscillations are periodic as a function of inverse
magnetic field. We find that both the magnetic oscillations, SdH and Weiss,
have a greater amplitude and are more robust against temperature in graphene
compared to conventional 2DEG. Furthermore, there is a $\pi$ phase shift
between the magnetoplasmon oscillations in the two systems which can be
attributed to Dirac electrons in graphene acquiring a Berry's phase as they
traverse a closed path in a magnetic field.


title:
Structural Disorder, Octahedral Coordination, and 2-Dimensional
  Ferromagnetism in Anhydrous Alums

abstract:
  The crystal structures of the triangular lattice, layered anhydrous alums
KCr(SO4)2, RbCr(SO4)2 and KAl(SO4)2 are characterized by X-ray and neutron
powder diffraction at temperatures between 1.4 and 773 K. The compounds all
crystallize in the space group P-3, with octahedral coordination of the
trivalent cations. In all cases, small amounts of disorder in the stacking of
the triangular layers of corner sharing MO6 octahedra and SO4 tetrahedra is
seen, with the MO6-SO4 network rotated in opposite directions between layers.
The electron diffraction study of KCr(SO4)2 supports this model, which on
average can be taken to imply trigonal prismatic coordination for the M3+ ions;
as was previously reported for the prototype anhydrous alum KAl(SO4)2. The
temperature dependent magnetic susceptibilities for ACr(SO4)2 (A = K,Rb,Cs)
indicate the presence of predominantly ferromagnetic interactions. Low
temperature powder neutron diffraction reveals that the magnetic ordering is
ferromagnetic in-plane, with antiferromagnetic ordering between planes below 3
K.


title: Superconductivity up to 29 K in SrFe2As2 and BaFe2As2 at high pressures

abstract:
  We report the discovery of superconductivity at high pressure in SrFe2As2 and
BaFe2As2. The superconducting transition temperatures are up to 27 K in
SrFe2As2 and 29 K in BaFe2As2, making these the highest pressure-induced
superconducting materials discovered thus far.


title: Looking at the Gregory-Laflamme instability through quasi-normal modes

abstract:
  We study evolution of gravitational perturbations of black strings. It is
well known that for all wavenumber less than some threshold value, the black
string is unstable against scalar type of gravitational perturbations, which is
named the Gregory-Laflamme instability. Using numerical methods, we find the
quasinormal modes and time-domain profiles of the black string perturbations in
the stable sector and also show the appearance of the Gregory-Laflamme
instability in the time domain. The dependence of the black string quasinormal
spectrum and late time tails on such parameters as the wave vector and the
number of extra dimensions is discussed. There is a numerical evidence that in
the threshold point of instability the static solution of the wave equation is
dominant. For wavenumbers slightly larger than the threshold value, in the
region of stability, we see tiny oscillations with very small damping rate.
While, for wavenumbers slightly smaller than the threshold value, in the region
of the Gregory-Laflamme instability, we observe tiny oscillations with very
small growth rate. We also find the level crossing of imaginary part of
quasinormal modes between the fundamental mode and the first overtone mode,
which accounts for the peculiar time domain profiles.


title: Universal Features in the Genome-level Evolution of Protein Domains

abstract:
  Protein domains are found on genomes with notable statistical distributions,
which bear a high degree of similarity. Previous work has shown how these
distributions can be accounted for by simple models, where the main ingredients
are probabilities of duplication, innovation, and loss of domains. However, no
one so far has addressed the issue that these distributions follow definite
trends depending on protein-coding genome size only. We present a stochastic
duplication/innovation model, falling in the class of so-called Chinese
Restaurant Processes, able to explain this feature of the data. Using only two
universal parameters, related to a minimal number of domains and to the
relative weight of innovation to duplication, the model reproduces two
important aspects: (a) the populations of domain classes (the sets, related to
homology classes, containing realizations of the same domain in different
proteins) follow common power-laws whose cutoff is dictated by genome size, and
(b) the number of domain families is universal and markedly sublinear in genome
size. An important ingredient of the model is that the innovation probability
decreases with genome size. We propose the possibility to interpret this as a
global constraint given by the cost of expanding an increasingly complex
interactome.


title: A ~1-hour X-ray periodicity in an active galaxy RE J1034+396

abstract:
  Active galactic nuclei and quasars are thought to be scaled up versions of
Galactic black hole binaries, powered by accretion onto supermassive black
holes with masses of 10^6-10^9 M_Sun, as opposed to the ~10 M_Sun in binaries.
One example of the similarities between these two types of systems is the
characteristic rapid X-ray variability seen from the accretion flow. The power
spectrum of this variability in black hole binaries consists of a broad,
band-limited noise with multiple quasi-periodic oscillations superimposed,
where power is concentrated over a narrow range of frequencies. Although the
broad noise component has been observed in many active galactic nuclei, there
are no significant detections of quasi-periodic oscillations. Here we report
the discovery of a ~1h X-ray periodicity in a bright active galaxy RE
J1034+396. The signal is highly statistically significant (at the 5.6 sigma
level) and very coherent, with quality factor Q > 16. This reinforces the link
between stellar and supermassive black holes, emphasizing the universal
properties of accretion onto objects with very different masses. The X-ray
modulation arises from the direct vicinity of the black hole, so this provides
a new tool for studying active galactic nuclei.


title: Classification of Almost Quarter-Pinched Manifolds

abstract:
  We show that if a simply connected manifold is almost quarter pinched then it
is diffeomorphic to a CROSS (a compact rank one symmetric space) or a sphere.


title:
Matter--wave emission in optical lattices: Single particle and
  collective effects

abstract:
  We introduce a simple set--up corresponding to the matter-wave analogue of
impurity atoms embedded in an infinite photonic crystal and interacting with
the radiation field. Atoms in a given internal level are trapped in an optical
lattice, and play the role of the impurities. Atoms in an untrapped level play
the role of the radiation field. The interaction is mediated by means of lasers
that couple those levels. By tuning the lasers parameters, it is possible to
drive the system through different regimes, and observe phenomena like matter
wave superradiance, non-Markovian atom emission, and the appearance of bound
atomic states.


title: Radial Dependence of the Pattern Speed of M51

abstract:
  The grand-design spiral galaxy M51 has long been a crucial target for
theories of spiral structure. Studies of this iconic spiral can address the
question of whether strong spiral structure is transient (e.g.
interaction-driven) or long-lasting. As a clue to the origin of the structure
in M51, we investigate evidence for radial variation in the spiral pattern
speed using the radial Tremaine-Weinberg (TWR) method. We implement the method
on CO observations tracing the ISM-dominant molecular component. Results from
the method's numerical implementation--combined with regularization, which
smooths intrinsically noisy solutions--indicate two distinct patterns speeds
inside 4 kpc at our derived major axis PA=170 deg., both ending at corotation
and both significantly higher than the conventionally adopted global value.
Inspection of the rotation curve suggests that the pattern speed interior to 2
kpc lacks an ILR, consistent with the leading structure seen in HST near-IR
observations. We also find tentative evidence for a lower pattern speed between
4 and 5.3 kpc measured by extending the regularized zone. As with the original
TW method, uncertainty in major axis position angle (PA) is the largest source
of error in the calculation; in this study, where \delta PA=+/-5 deg. a ~20%
error is introduced to the parameters of the speeds at PA=170 deg. Accessory to
this standard uncertainty, solutions with PA=175 deg. (also admitted by the
data) exhibit only one pattern speed inside 4 kpc, and we consider this
circumstance under the semblance of a radially varying PA.


title:
Execution and Other Details for New Space Experiment Proposed for
  General Relativity

abstract:
  Following two dictums roadmap of Einstein (one, for incorporation of maximum
of empirical facts, and the other, on long continued experimental verifications
for perfecting a scientific theory) for future generations to make his General
Relativity Theory (GRT) evolve to perfection, it is necessary to experimentally
confirm his concept on General relativistic nature of speed of light, c, which
relates to the variation of c under the influence of gravitational field, and
whose experimental confirmation is long overdue.
  This paper gives the Execution and some Additional Details for the Space
Experiment Proposed for GRT, so that any of the Space research organizations
(viz., NASA, ESA, ASI, ISRO, etc.) would conduct this low cost experiment,
during Space missions to Mercury, Venus, or the sun, or may choose to conduct
it as an independent space mission as the cost may be brought down by sending
micro satellites using the launch sharing facility of any other lending
country. Even an advanced country may conduct this experiment at low cost by
sending a micro satellite (called a co-passenger satellite) by arranging with
the Space research organization of any lending country, which is sending a
primary satellite for a space mission to any of the desired locations.
  At present, even a small country interested in making a historic contribution
for making GRT of Einstein evolve, but not having a Space research
organization, may contract with an experienced organization, or hire the
services of an experienced project director who
  * can organize the planning, procurement, and launching of a micro satellite
carrying the laser device, from launch pad of another country (adopting the
piggy back launching method), and
  * can guide (else, can hire the services of a Principal Investigator, from
some renowned institute) remote operation of the laser device for a few days.


title: A space-time characterization of the Kerr-Newman metric

abstract:
  In the present paper, the characterization of the Kerr metric found by Marc
Mars is extended to the Kerr-Newman family. A simultaneous alignment of the
Maxwell field, the Ernst two-form of the pseudo-stationary Killing vector
field, and the Weyl curvature of the metric is shown to imply that the
space-time is locally isometric to domains in the Kerr-Newman metric. The paper
also presents an extension of Ionescu and Klainerman's null tetrad formalism to
explicitly include Ricci curvature terms.


title: Two-Dimensional Wess-Zumino Models at Intermediate Couplings

abstract:
  We consider the two-dimensional N=(2,2) Wess-Zumino model with a cubic
superpotential at weak and intermediate couplings. Refined algorithms allow for
the extraction of reliable masses in a region where perturbation theory no
longer applies. We scrutinize the Nicolai improvement program which is supposed
to guarantee lattice supersymmetry and compare the results for ordinary and
non-standard Wilson fermions with those for SLAC derivatives. It turns out that
this improvement completely fails to enhance simulations for Wilson fermions
and only leads to better results for SLAC fermions. Furthermore, even without
improvement terms the models with all three fermion species reproduce the
correct values for the fermion masses in the continuum limit.


title:
Extension of Inagaki General Weighted Operators and A New Fusion Rule
  Class of Proportional Redistribution of Intersection Masses

abstract:
  In this paper we extend Inagaki Weighted Operators fusion rule (WO) in
information fusion by doing redistribution of not only the conflicting mass,
but also of masses of non-empty intersections, that we call Double Weighted
Operators (DWO). Then we propose a new fusion rule Class of Proportional
Redistribution of Intersection Masses (CPRIM), which generates many interesting
particular fusion rules in information fusion. Both formulas are presented for
any number of sources of information. An application and comparison with other
fusion rules are given in the last section.


title:
The hyperfine energy levels of alkali metal dimers: ground-state polar
  molecules in electric and magnetic fields

abstract:
  We investigate the energy levels of heteronuclear alkali metal dimers in
levels correlating with the lowest rotational level of the ground electronic
state, which are important in efforts to produce ground-state ultracold
molecules. We use density-functional theory to calculate nuclear quadrupole and
magnetic coupling constants for RbK and RbCs and explore the hyperfine
structure in the presence of electric and magnetic fields. For nonrotating
states, the zero-field splittings are dominated by the electron-mediated part
of the nuclear spin-spin coupling. They are a few kHz for RbK isotopologs and a
few tens of kHz for RbCs isotopologs.


title: Confinement and Localization on Domain Walls

abstract:
  We continue the studies of localization of the U(1) gauge fields on domain
walls. Depending on dynamics of the bulk theory the gauge field localized on
the domain wall can be either in the Coulomb phase or squeezed into flux tubes
implying (Abelian) confinement of probe charges on the wall along the wall
surface. First, we consider a simple toy model with one flavor in the bulk at
weak coupling (a minimal model) realizing the latter scenario. We then suggest
a model presenting an extension of the Seiberg--Witten theory which is at
strong coupling, but all theoretical constructions are under full control if we
base our analysis on a dual effective action. Finally, we compare our findings
with the wall in a "nonminimal" theory with two distinct quark flavors that had
been studied previously. In this case the U(1) gauge field trapped on the wall
is exactly massless because it is the Goldstone boson of a U(1) symmetry in the
bulk spontaneously broken on the wall. The theory on the wall is in the Coulomb
phase. We explain why the mechanism of confinement discussed in the first part
of the paper does not work in this case, and strings are not formed on the
walls.


title:
Generation of optical combs in a whispering gallery mode resonator from
  a bichromatic pump

abstract:
  An optical comb is shown to arise from a whispering gallery mode resonator
pumped by two optical frequencies. Two externally excited modes couple due to
Kerr nonlinearity to initially empty modes and give rise to new frequency
components. This thresholdles process is much more efficient than the
previously reported single-pump four-wave mixing. As a result, a few milliwatt
pump is sufficient to generate strong secondary fields, that efficiently
generate higher-order frequency components and so on, in a cascade process
leading to an optical comb.


title:
Influence of atomic collisions on spectrum of light scattered from an
  f-deformed Bose-Einstein condensate

abstract:
  In this paper, we investigate the spectrum of light scattered from a
Bose-Einstein condensate in the framework of f-deformed boson. We use an
f-deformed quantum model in which the Gardiners phonon operators for BEC are
deformed by an operator-valued function, f(n), of the particle-number operator
n. We consider the collisions between the atoms as a special kind of
f-deformation. The collision rate k is regarded as the deformation parameter
and the spectrum of light scattered from the deformed BEC is analyzed. In
particular, we find that with increasing the values of deformation parameters k
and eta=1/N (N, total number of condensate atoms) the scattering spectrum shows
deviation from the spectrum associated with nondeformed Bose-Einstein
condensate.


title: String orientations of simplicial homology manifolds

abstract:
  Simplicial homology manifolds are proposed as an interesting class of
geometric objects, more general than topological manifolds but still quite
tractable, in which questions about the microstructure of space-time can be
naturally formulated. Their string orientations are classified by $H^3$ with
coefficients in an extension of the usual group of D-brane charges, by
cobordism classes of homology three-spheres with trivial Rokhlin invariant.


title: Real-Time Calibration of the Murchison Widefield Array

abstract:
  The interferometric technique known as peeling addresses many of the
challenges faced when observing with low-frequency radio arrays, and is a
promising tool for the associated calibration systems. We investigate a
real-time peeling implementation for next-generation radio interferometers such
as the Murchison Widefield Array (MWA). The MWA is being built in Australia and
will observe the radio sky between 80 and 300 MHz. The data rate produced by
the correlator is just over 19 GB/s (a few Peta-Bytes/day). It is impractical
to store data generated at this rate, and software is currently being developed
to calibrate and form images in real time. The software will run on-site on a
high-throughput real-time computing cluster at several tera-flops, and a
complete cycle of calibration and imaging will be completed every 8 seconds.
Various properties of the implementation are investigated using simulated data.
The algorithm is seen to work in the presence of strong galactic emission and
with various ionospheric conditions. It is also shown to scale well as the
number of antennas increases, which is essential for many upcoming instuments.
Lessons from MWA pipeline development and processing of simulated data may be
applied to future low-frequency fixed dipole arrays.


title: Revision of Star-Formation Measures

abstract:
  Rotation plays a major role in the evolution of massive stars. A revised grid
of stellar evolutionary tracks accounting for rotation has recently been
released by the Geneva group and implemented into the Starburst99 evolutionary
synthesis code. Massive stars are predicted to be hotter and more luminous than
previously thought, and the spectral energy distributions of young populations
mirror this trend. The hydrogen ionizing continuum in particular increases by a
factor of up to 3 in the presence of rotating massive stars. The effects of
rotation generally increase towards shorter wavelengths and with decreasing
metallicity. Revised relations between star-formation rates and monochromatic
luminosities for the new stellar models are presented.


title:
Stochastic backgrounds of relic gravitons, T$\Lambda$CDM paradigm and
  the stiff ages

abstract:
  Absent any indirect tests on the thermal history of the Universe prior to the
formation of light nuclear elements, it is legitimate to investigate situations
where, before nucleosyntheis, the sound speed of the plasma was larger than
$c/\sqrt{3}$, at most equalling the speed of light $c$. In this plausible
extension of the current cosmological paradigm, hereby dubbed
Tensor-$\Lambda$CDM (i.e. T$\Lambda$CDM) scenario, high-frequency gravitons are
copiously produced. Without conflicting with the bounds on the tensor to scalar
ratio stemming from the combined analysis of the three standard cosmological
data sets (i.e. cosmic microwave background anisotropies, large-scale structure
and supenovae), the spectral energy density of the relic gravitons in the
T$\Lambda$CDM scenario can be potentially observable by wide-band
interferometers (in their advanced version) operating in a frequency window
which ranges between few Hz and few kHz.


title: Theory and laboratory tests of the multi-stage phase mask coronagraph

abstract:
  A large number of coronagraphs have been proposed to overcome the ratio that
exists between the star and its planet. The planet finder of the Extremely
Large Telescope, which is called EPICS, will certainly need a more efficient
coronagraph than the ones that have been developed so far. We propose to use a
combination of chromatic Four Quadrant Phase Mask coronagraph to achromatize
the dephasing of the device while maintaining a high rejection performance.
After describing this multi-stage FQPM coronagraph, we show preliminary results
of a study on its capabilities in the framework of the EPICS instrument, the
planet finder of the European Extremely Large Telescope. Eventually, we present
laboratory tests of a rough prototype of a multi-stage four-quadrant phase
mask. On one hand, we deduce from our laboratory data that a detection at the
10^-10 level is feasible in monochromatic light. On the other hand, we show the
detection of a laboratory companion fainter than 10^-8 with a spectral
bandwidth larger than 20%.


title: Initial logarithmic Lie algebras of hypersurface singularities

abstract:
  We introduce a Lie algebra of initial terms of logarithmic vector fields
along a hypersurface singularity. Extending the formal structure theorem in
[GS06, Thm. 5.4], we show that the completely reducible part of its linear
projection lifts formally to a linear Lie algebra of logarithmic vector fields.
For quasihomogeneous singularities, we prove convergence of this linearization.
We relate our construction to the work of Hauser and M"uller [M"ul86, HM89] on
Levi subgroups of automorphism groups of singularities, which proves
convergence even for algebraic singularities. Based on the initial Lie algebra,
we introduce a notion of reductive hypersurface singularity and show that any
reductive free divisor is linear. As an application, we describe a lower bound
for the dimension of hypersurface singularities in terms of the semisimple part
of their initial Lie algebra.


title: Deep inelastic scattering from gauge string duality in D3-D7 brane model

abstract:
  We calculate deep inelastic structure functions for mesons in the D3-D7 brane
model, that incorporates flavour to the AdS/CFT correspondence. We consider two
different prescriptions for the hadronic current dual: a gauge field in the AdS
bulk and a gauge field on the D7 brane. We also calculate elastic form factors
in both cases. We compare our results with other holographic models.


title: On the Gaussian q-Distribution

abstract:
  We present a study of the Gaussian q-measure introduced by Diaz and Teruel
from a probabilistic and from a combinatorial viewpoint. A main motivation for
the introduction of the Gaussian q-measure is that its moments are exactly the
q-analogues of the double factorial numbers. We show that the Gaussian
q-measure interpolates between the uniform measure on the interval [-1,1] and
the Gaussian measure on the real line.


title:
The Johnson-Lindenstrauss lemma almost characterizes Hilbert space, but
  not quite

abstract:
  Let $X$ be a normed space that satisfies the Johnson-Lindenstrauss lemma (J-L
lemma, in short) in the sense that for any integer $n$ and any
$x_1,\ldots,x_n\in X$ there exists a linear mapping $L:X\to F$, where
$F\subseteq X$ is a linear subspace of dimension $O(\log n)$, such that
$\|x_i-x_j\|\le\|L(x_i)-L(x_j)\|\le O(1)\cdot\|x_i-x_j\|$ for all $i,j\in
\{1,\ldots, n\}$. We show that this implies that $X$ is almost Euclidean in the
following sense: Every $n$-dimensional subspace of $X$ embeds into Hilbert
space with distortion $2^{2^{O(\log^*n)}}$. On the other hand, we show that
there exists a normed space $Y$ which satisfies the J-L lemma, but for every
$n$ there exists an $n$-dimensional subspace $E_n\subseteq Y$ whose Euclidean
distortion is at least $2^{\Omega(\alpha(n))}$, where $\alpha$ is the inverse
Ackermann function.


title:
Optical to UV spectra and birefringence of SiO$_2$ and TiO$_2$:
  First-principles calculations with excitonic effects

abstract:
  A first principles approach is presented for calculations of optical --
ultraviolet (UV) spectra including excitonic effects. The approach is based on
Bethe-Salpeter equation calculations using the \textsc{NBSE} code combined with
ground-state density-functional theory calculations from the electronic
structure code \textsc{ABINIT}. Test calculations for bulk Si are presented,
and the approach is illustrated with calculations of the optical spectra and
birefringence of $\alpha$-phase SiO$_2$ and the rutile and anatase phases of
TiO$_2$. An interpretation of the strong birefringence in TiO$_2$ is presented.


title:
Reconstructing the Guitar: Blowing Bubbles with a Pulsar Bow Shock Back
  Flow

abstract:
  The Guitar Nebula is an H-alpha nebula produced by the interaction of the
relativistic wind of a very fast pulsar, PSR B2224+65, with the interstellar
medium. It consists of a ram-pressure confined bow shock near its head and a
series of semi-circular bubbles further behind, the two largest of which form
the body of the Guitar. We present a scenario in which this peculiar morphology
is due to instabilities in the back flow from the pulsar bow shock. From
simulations, these back flows appear similar to jets and their kinetic energy
is a large fraction of the total energy in the pulsar's relativistic wind. We
suggest that, like jets, these flows become unstable some distance down-stream,
leading to rapid dissipation of the kinetic energy into heat, and the formation
of an expanding bubble. We show that in this scenario the sizes, velocities,
and surface brightnesses of the bubbles depend mostly on observables, and that
they match roughly what is seen for the Guitar. Similar instabilities may
account for features seen in other bow shocks.


title:
A PL-manifold of nonnegative curvature homeomorphic to $S^2 \times S^2$
  is a direct metric product (Preliminary version)

abstract:
  Let $M^4$ be a PL-manifold of nonnegative curvature that is homeomorphic to a
product of two spheres, $S^2 \times S^2$. We prove that $M$ is a direct metric
product of two spheres endowed with some polyhedral metrics. In other words,
$M$ is a direct metric product of the surfaces of two convex polyhedra in
$\mathbb{R}^3$.
  The background for the question is the following. The classical H.Hopf's
hypothesis states: for any Riemannian metric on $S^2 \times S^2$ of nonnegative
sectional curvature the curvature cannot be strictly positive at all points.
There is no quick answer to this question: it is known that a Riemannian metric
on $S^2 \times S^2$ of nonnegative sectional curvature need not be a product
metric. However, M.Gromov has pointed out that the condition of nonnegative
curvature in the PL-case appears to be stronger than nonnegative sectional
curvature of Riemannian manifolds and analogous to some condition on the
curvature operator. So the motivation for the question addressed in this text
is to settle the PL-version of the Hopf's hypothesis.


title:
Emergent multipolar spin correlations in a fluctuating spiral - The
  frustrated ferromagnetic S=1/2 Heisenberg chain in a magnetic field

abstract:
  We present the phase diagram of the frustrated ferromagnetic S=1/2 Heisenberg
J_1-J_2 chain in a magnetic field, obtained by large scale exact
diagonalizations and density matrix renormalization group simulations. A vector
chirally ordered state, metamagnetic behavior and a sequence of spin-multipolar
Luttinger liquid phases up to hexadecupolar kind are found. We provide
numerical evidence for a locking mechanism, which can drive spiral states
towards spin-multipolar phases, such as quadrupolar or octupolar phases. Our
results also shed light on previously discovered spin-multipolar phases in
two-dimensional $S=1/2$ quantum magnets in a magnetic field.


title:
N=6 super Chern-Simons theory S-matrix and all-loop Bethe ansatz
  equations

abstract:
  We propose the exact S-matrix for the planar limit of the N=6 super
Chern-Simons theory recently proposed by Aharony, Bergman, Jafferis, and
Maldacena for the AdS_4/CFT_3 correspondence. Assuming SU(2|2) symmetry,
factorizability and certain crossing-unitarity relations, we find the S-matrix
including the dressing phase. We use this S-matrix to formulate the asymptotic
Bethe ansatz. Our result for the Bethe-Yang equations and corresponding Bethe
ansatz equations confirms the all-loop Bethe ansatz equations recently
conjectured by Gromov and Vieira.


title:
Uncovering Extremely Metal-Poor Stars in the Milky Way's Ultra-Faint
  Dwarf Spheroidal Satellite Galaxies

abstract:
  We present new metallicity measurements for 298 individual red giant branch
stars in eight of the least luminous dwarf spheroidal galaxies (dSphs) in the
Milky Way (MW) system. Our technique is based on medium resolution Keck/DEIMOS
spectroscopy coupled with spectral synthesis. We present the first
spectroscopic metallicities at [Fe/H] < -3.0 of stars in a dwarf galaxy, with
individual stellar metallicities as low as [Fe/H] = -3.3. Because our [Fe/H]
measurements are not tied to empirical metallicity calibrators and are
sensitive to arbitrarily low metallicities, we are able to probe this extremely
metal-poor regime accurately. The metallicity distribution of stars in these
dSphs is similar to the MW halo at the metal-poor end. We also demonstrate that
the luminosity-metallicity relation previously seen in more luminous dSph
galaxies (M_V = -13.4 to -8.8) extends smoothly down to an absolute magnitude
of M_V = -3.7. The discovery of extremely metal-poor stars in dSphs lends
support to the LCDM galaxy assembly paradigm wherein dwarf galaxies dissolve to
form the stellar halo of the MW.


title: Treating the b quark distribution function with reliable uncertainties

abstract:
  The parton distribution function for a b quark in the B meson (called the
shape function) plays an important role in the analysis of the B -> X_s gamma
and B -> X_u l nu data, and gives one of the dominant uncertainties in the
determination of |Vub|. We introduce a new framework to treat the shape
function, which consistently incorporates its renormalization group evolution
and all constraints on its shape and moments in any short distance mass scheme.
At the same time it allows a reliable treatment of the uncertainties. We
develop an expansion in a suitable complete set of orthonormal basis functions,
which provides a procedure for systematically controlling the uncertainties due
to the unknown functional form of the shape function. This is a significant
improvement over fits to model functions. Given any model for the shape
function, our construction gives an orthonormal basis in which the model occurs
as the first term, and corrections to it can be studied. We introduce a new
short distance scheme, the "invisible scheme", for the kinetic energy matrix
element, lambda_1. We obtain closed form results for the differential rates
that incorporate perturbative corrections and a summations of logarithms at any
order in perturbation theory, and present results using known
next-to-next-to-leading order expressions. The experimental implementation of
our framework is straightforward.


title: Systematics of multi-field effects at the end of warped brane inflation

abstract:
  We investigate in the context of brane inflation the possibility of
additional light scalar fields generating significant power spectrum and
non-Gaussianities at the end of inflation affecting the CMB scale observations.
We consider the specific mechanism outlined by Lyth and describe the necessary
criteria for it to be potentially important in a warped throat. We also discuss
different mechanisms for uplifting the vacuum energy which can lead to
different dominant contributions of the inflaton potential near the end of
inflation. We then apply such criteria to one of the most detailed brane
inflation models to date, and show that inflation can persist towards the tip
of the throat, however for the specific stable inflationary trajectory, the
light residual isometry direction becomes degenerate. We also estimate the
effects for other inflationary trajectories with non-degenerate residual
isometries.


title:
Towards the Albedo of an Exoplanet: MOST Satellite Observations of
  Bright Transiting Exoplanetary Systems

abstract:
  The Canadian MOST satellite is a unique platform for observations of bright
transiting exoplanetary systems. Providing nearly continuous photometric
observations for up to 8 weeks, MOST can produce important observational data
to help us learn about the properties of exosolar planets. We review our
current observations of HD 209458, HD 189733 with implications towards the
albedo and our progress towards detecting reflected light from an exoplanet.


title:
The Galactic Center as a laboratory for extreme mass ratio gravitational
  wave source dynamics

abstract:
  The massive Galactic black hole and the stars around it are a unique
laboratory for studying how relaxation processes lead to close interactions of
stars and compact remnants with the central massive black hole, in particular
those leading to the emission of gravitational waves. I review new results on
the processes of strong mass segregation and loss-cone refilling by massive
perturbers and resonant relaxation; describe observational evidence that these
processes play a role in the Galactic Center and can be studied there; and
discuss some of the implications for Extreme Mass Ration Inspiral event rates
and their properties.


title: Astrometric Detection of exo-Earths in the Presence of Stellar Noise

abstract:
  Space astrometry is capable of sub-microarcsecond measurements of star
positions. A hundred visits over several years could yield relative astrometric
precision of ~0.1 uas, below the astrometric signature (0.3 uas) of a Sun-Earth
system at a distance of 10 parsecs. We investigate the impact of starspots on
the detectability, via astrometric and radial velocity techniques, of Earthlike
planets orbiting Sunlike stars. We find that for nearby stars, although
starspot noise imposes severe restrictions on detectability by the radial
velocity technique, it does not significantly affect astrometric detectability
of habitable zone planets down to below an Earth mass.


title: Multipole Formulae for Gravitational Lensing Shear and Flexion

abstract:
  The gravitational lensing equations for convergence, potential, shear, and
flexion are simple in polar coordinates and separate under a multipole
expansion once the shear and flexion spinors are rotated into a ``tangential''
basis. We use this to investigate whether the useful monopole aperture-mass
shear formulae generalize to all multipoles and to flexions. We re-derive the
result of Schneider and Bartelmann that the shear multipole m at radius R is
completely determined by the mass multipole at R, plus specific moments Q^m_in
and Q^m_out of the mass multipoles internal and external, respectively, to R.
The m>=0 multipoles are independent of Q_out. But in contrast to the monopole,
the m<0 multipoles are independent of Q_in. These internal and external mass
moments can be determined by shear (and/or flexion) data on the complementary
portion of the plane, which has practical implications for lens modelling. We
find that the ease of E/B separation in the monopole aperture moments does {\em
not} generalize to m!=0: the internal monopole moment is the {\em only}
non-local E/B discriminant available from lensing observations. We have also
not found practical local E/B discriminants beyond the monopole, though they
could exist. We show also that the use of weak-lensing data to constrain a
constant shear term near a strong-lensing system is impractical without strong
prior constraints on the neighboring mass distribution.


title: Detection of Magnetic Massive Stars in the Open Cluster NGC 3766

abstract:
  A growing number of observations indicate that magnetic fields are present
among a small fraction of massive O- and B-type stars, yet the origin of these
fields remains unclear. Here we present the results of a VLT/FORS1
spectropolarimetric survey of 15 B-type members of the open cluster NGC 3766.
We have detected two magnetic B stars in the cluster, including one with a
large field of nearly 2 kG, and we find marginal detections of two additional
stars. There is no correlation between the observed longitudinal field
strengths and the projected rotational velocity, suggesting that a dynamo
origin for the fields is unlikely. We also use the Oblique Dipole Rotator model
to simulate populations of magnetic stars with uniform or slightly varying
magnetic flux on the ZAMS. None of the models successfully reproduces our
observed range in B_l and the expected number of field detections, and we rule
out a purely fossil origin for the observed fields.


title:
Scaling and commensurate-incommensurate crossover for the d=2, z=2
  quantum critical point of itinerant antiferromagnets

abstract:
  Quantum critical points exist at zero temperature, yet, experimentally their
influence seems to extend over a large part of the phase diagram of systems
such as heavy-fermion compounds and high-temperature superconductors.
Theoretically, however, it is generally not known over what range of parameters
the physics is governed by the quantum critical point. We answer this question
for the spin-density wave to fermi-liquid quantum critical point in the
two-dimensional Hubbard model. This problem is in the $d=2,z=2$ universality
class. We use the Two-Particle Self-Consistent approach, which is accurate from
weak to intermediate coupling, and whose critical behavior is the same as for
the self-consistent-renormalized approach of Moriya. Despite the presence of
logarithmic corrections, numerical results demonstrate that quantum critical
scaling for the static magnetic susceptibility can extend up to very high
temperatures but that the commensurate to incommensurate crossover leads to
deviations to scaling.


title: Spin Correlations in the Geometrically Frustrated Pyrochlore Tb2Mo2O7

abstract:
  We report neutron scattering studies of the spin correlations of the
geometrically frustrated pyrochlore Tb2Mo2O7 using single crystal samples. This
material undergoes a spin-freezing transition below Tg~24 K, similar to
Y2Mo2O7, and has little apparent chemical disorder. Diffuse elastic peaks are
observed at low temperatures, indicating short-range ordering of the Tb moments
in an arrangement where the Tb moments are slightly rotated from the preferred
directions of the spin ice structure. In addition, a Q-independent signal is
observed which likely originates from frozen, but completely uncorrelated, Tb
moments. Inelastic measurements show the absence of sharp peaks due to crystal
field excitations. These data show how the physics of the Tb sublattice
responds to the glassy behavior of the Mo sublattice with the associated
effects of lattice disorder.


title: Crosslinked networks of stiff filaments exhibit negative normal stress

abstract:
  Motivated by recent experiments showing that stiff biopolymer gels exhibit
highly unusual negative normal elastic stresses, we develop a computational
model for stiff polymer networks subject to large strains. In all cases, we
find that such networks develop normal stresses that are both negative and of
magnitude comparable to the corresponding shear stress. We find that these
normal stresses coincide with other nonlinearities in our networks, and
specifically with compressive bucking of the individual filaments. Our results
suggest that negative normal stresses are a characteristic feature of stiff
(bio)polymer gels that have been shown to exhibit strong nonlinear elastic
properties.


title: Twist instability in strongly correlated carbon nanotubes

abstract:
  We show that strong Luttinger correlations of the electron liquid in armchair
carbon nanotubes lead to a significant enhancement of the onset temperature of
the putative twist Peierls instability. The instability results in a
spontaneous uniform twist deformation of the lattice at low temperatures, and a
gapped ground state. Depending on values of the coupling constants the umklapp
electron scattering processes can assist or compete with the twist instability.
In case of the competition the umklapp processes win in wide tubes. In narrow
tubes the outcome of the competition depends on the relative strength of the
e-e and e-ph backscattering. Our estimates show that the twist instability may
be realized in free standing (5,5) tubes.


title:
Security of two-way quantum cryptography against asymmetric Gaussian
  attacks

abstract:
  Recently, we have shown the advantages of two-way quantum communications in
continuous variable quantum cryptography. Thanks to this new approach, two
honest users can achieve a non-trivial security enhancement as long as the
Gaussian interactions of an eavesdropper are independent and identical. In this
work, we consider asymmetric strategies where the Gaussian interactions can be
different and classically correlated. For several attacks of this kind, we
prove that the enhancement of security still holds when the two-way protocols
are used in direct reconciliation.


title:
Particle absorption by black holes and the generalized second law of
  thermodynamics

abstract:
  The change in entropy, /DeltaS, associated with the quasi-static absorption
of a particle of energy u by a Schwarzschild black hole (ScBH) is approximately
(u/T)-s, where T is the Hawking temperature of the black hole and s is the
entropy of the particle. Motivated by the statistical interpretation of
entropy, it is proposed here that absorption should be suppressed, but not
forbidden, when /DeltaS<0, which requires the absorption cross-section to be
sensitive to /DeltaS. A purely thermodynamic formulation of the probability for
absorption is obtained from the standard relationship between microstates and
entropy. If /DeltaS>>1 and s<<u/T then the probability for the particle not to
be absorbed is approximately exp[-u/T], which is identical to the probability
for quantum mechanical reflection by the horizon of a ScBH. The manifestation
of quantum behaviors in the new probability function may intimate a fundamental
physical unity between thermodynamics and quantum mechanics.


title:
Noncommutative Black Holes, The Final Appeal To Quantum Gravity: A
  Review

abstract:
  We present the state of the art regarding the relation between the physics of
Quantum Black Holes and Noncommutative Geometry. We start with a review of
models proposed in the literature for describing deformations of General
Relativity in the presence of noncommutativity, seen as an effective theory of
Quantum Gravity. We study the resulting metrics, proposed to replace or at
least to improve the conventional black hole solutions of Einstein's equation.
In particular, we analyze noncommutative-inspired solutions obtained in terms
of quasi-classical noncommutative coordinates: indeed because of their
surprising new features, these solutions enable us to circumvent long standing
problems with Quantum Field Theory in Curved Space and to cure the singular
behavior of gravity at the centers of black holes. As a consequence, for the
first time, we get a complete description of what we may call the black hole
SCRAM, the shut down of the emission of thermal radiation from the black hole:
in place of the conventional scenario of runaway evaporation in the Planck
phase, we find a zero temperature final state, a stable black hole remnant,
whose size and mass are determined uniquely in terms of the noncommutative
parameter $\theta$. This result turns out to be of vital importance for the
physics of the forthcoming experiments at the LHC, where mini black hole
production is foreseen in extreme energy hadron collisions. Because of this, we
devote the final part of this review to higher dimensional solutions and their
phenomenological implications for TeV Gravity.


title: The Role of Collinear Photons in the Rare Decay anti-B --> X(s) l+ l-

abstract:
  We review the phenomenology of the rare decay \bar B -> X_s l+ l-. We present
the results of a detailed phenomenological analysis and discuss the role of the
decay in the search for new physics at present and future colliders. Moreover,
we extensively elaborate on the size of electromagnetic logarithms
ln(m_b^2/m_l^2) in view of experimental cuts. We point out the differences in
the analyses of BaBar and Belle and give suggestions on how to treat collinear
photons in the experimental analyses. These recommendations correspond
precisely to theoretical prescriptions and can be combined with measurements
performed at a Super-B factory.


title:
Long-Range Multiplicity Correlations in Relativistic Heavy Ion
  Collisions as a Signal for Dense Partonic Matter

abstract:
  A dense form of matter is formed in relativistic heavy ion collisions. The
constituent degrees of freedom in this dense matter are currently unknown.
Long-range, forward-backward multiplicity correlations (LRC) are expected to
arise due to multiple partonic interactions. Model independent and dependent
arguments suggest that such correlations are due to multiple partonic
interactions. These correlations are predicted in the context of the Dual
Parton Model (DPM). The DPM describes soft partonic processes and
hadronization. This model indicates that the underlying mechanism creating
these long-range multiplicity correlations in the bulk matter is due to
multiple partonic interactions.
  In this thesis, long-range multiplicity correlations have been studied in
heavy ion (Au+Au and Cu+Cu) and hadron-hadron ({\it pp}) collisions. The
behavior has been studied as a function of pseudorapidity gap ($\Delta\eta$)
about $\eta$ = 0, the centrality, atomic number, and incident energy dependence
of the colliding particles. Strong, long-range correlations ($\Delta\eta >$
1.0) as a function of $\Delta\eta$ are found for central collisions of %(full
overlap) heavy ions at an energy of $\sqrt{s_{NN}}$ = 200 GeV. This indicates
substantial amounts of dense partonic matter are formed in central heavy ion
collisions at an energy of $\sqrt{s_{NN}}$ = 200 GeV.


title: Clues to Radial Migration from the Properties of Outer Disks

abstract:
  The outer disks of galaxies present a unique laboratory for studying the
process of disk formation. A considerable fraction of observed disks exhibit a
break in their surface brightness profiles. The ubiquity of these features
points to a crucial aspect of disk formation which must be explained. Recent
theoretical work suggests that such breaks are related to significant amounts
of radial migration. We discuss the current observational evidence which
supports this picture.


title: Failure of antibiotic treatment in microbial populations

abstract:
  The tolerance of bacterial populations to biocidal or antibiotic treatment
has been well documented in both biofilm and planktonic settings. However,
there is still very little known about the mechanisms that produce this
tolerance. Evidence that small, non-mutant subpopulations of bacteria are not
affected by antibiotic challenge has been accumulating and provides an
attractive explanation for the failure of typical dosing protocols. Although a
dosing challenge can kill all the susceptible bacteria, the remaining persister
cells can serve as a source of population regrowth. We give a robust condition
for the failure of a periodic dosing protocol for a general chemostat model,
which supports the mathematical conclusions and simulations of an earlier, more
specialized batch model. Our condition implies that the treatment protocol
fails globally, in the sense that a mixed bacterial population will ultimately
persist above a level that is independent of the initial composition of the
population. We also give a sufficient condition for treatment success, at least
for initial population compositions near the steady state of interest,
corresponding to bacterial washout. Finally, we investigate how the speed at
which the bacteria are wiped out depends on the duration of administration of
the antibiotic. We find that this dependence is not necessarily monotone,
implying that optimal dosing does not necessarily correspond to continuous
administration of the antibiotic. Thus, genuine periodic protocols can be more
advantageous in treating a wide variety of bacterial infections.


title:
Binarity in Cool Asymptotic Giant Branch Stars: A Galex Search for
  Ultraviolet Excesse

abstract:
  The search for binarity in AGB stars is of critical importance for our
understanding of how planetary nebulae acquire the dazzling variety of
aspherical shapes which characterises this class. However, detecting binary
companions in such stars has been severely hampered due to their extreme
luminosities and pulsations. We have carried out a small imaging survey of AGB
stars in ultraviolet light (using GALEX) where these cool objects are very
faint, in order to search for hotter companions. We report the discovery of
significant far-ultraviolet excesses towards nine of these stars. The
far-ultraviolet excess most likely results either directly from the presence of
a hot binary companion, or indirectly from a hot accretion disk around the
companion.


title: Dynamics of Quantum Vorticity in a Random Potential

abstract:
  I study the dynamics of a superfluid vortex in a random potential, as in the
inner crust of a neutron star. Below a critical flow velocity of the ambient
superfluid, a vortex is effectively immobilized by lattice forces even in the
limit of zero dissipation. Low-velocity, translatory motion is not dynamically
possible, a result with important implications for understanding neutron star
precession and the dynamical properties of superfluid nuclear matter.


title:
The estimate of kinetic powers of jets in FRII radio galaxies: existence
  of invisible components?

abstract:
  We investigate the total kinetic powers (L_j) and ages (t_age) of powerful
jets in FR II radio galaxies by comparison of the dynamical model of expanding
cocoons with observations. We select four FR II radio sources (Cygnus A, 3C
223, 3C 284, and 3C 219), for which the mass-density profiles of intracluster
medium (ICM) are known in the literature. It is found that large fractions >
0.02 - 0.7 of the Eddington luminosity (L_Edd) are carried away as a kinetic
power of jet. The upper limit of estimated 2 L_j / L_Edd are larger than unity
(< 10) for some sources, suggesting a possibility of super-Eddington mass
accretions. As a consequence of the large powers, we also find that the total
energy stored in the cocoon (E_c) exceeds the energy derived from the minimum
energy condition for the energy of radiating non-thermal electrons and magnetic
fields (E_min): 4< E_c /E_min <310. This implies that most of the energy in
cocoon is carried by invisible components such as thermal leptons (electron and
positron) and/or protons.


title: Future Foam

abstract:
  We study pocket universes which have zero cosmological constant and
non-trivial boundary topology. These arise from bubble collisions in eternal
inflation. Using a simplified dust model of collisions we find that boundaries
of any genus can occur. Using a radiation shell model we perform analytic
studies in the thin wall limit to show the existence of geometries with a
single toroidal boundary. We give plausibility arguments that higher genus
boundaries can also occur. In geometries with one boundary of any genus a
timelike observer can see the entire boundary. Geometries with multiple
disconnected boundaries can also occur. In the spherical case with two
boundaries the boundaries are separated by a horizon. Our results suggest that
the holographic dual description for eternal inflation, proposed by Freivogel,
Sekino, Susskind and Yeh, should include summation over the genus of the base
space of the dual conformal field theory. We point out peculiarities of this
genus expansion compared to the string perturbation series.


title: Magnetic Propeller for Uniform Magnetic Field Levitation

abstract:
  Three new approaches to generating thrust in uniform magnetic fields are
proposed. The first direction is based on employing Lorentz force acting on
partial magnetically shielded 8-shaped loop with current in external magnetic
field, whereby a net force rather than a torque origins. Another approach,
called a Virtual Wire System, is based on creating a magnetic field having an
energetic symmetry (a virtual wire), with further superposition of external
field. The external field breaks the symmetry causing origination of a net
force. Unlike a wire with current, having radial energetic symmetry, the
symmetry of the Virtual Wire System is closer to an axial wire. The third
approach refers to the first two. It is based on creation of developed surface
system, comprising the elements of the first two types. The developed surface
approach is a way to drastically increase a thrust-to-weight ratio. The
conducted experiments have confirmed feasibility of the proposed approaches.


title:
Virtual Transmission Method, A New Distributed Algorithm to Solve Sparse
  Linear System

abstract:
  In this paper, we propose a new parallel algorithm which could work naturally
on the parallel computer with arbitrary number of processors. This algorithm is
named Virtual Transmission Method (VTM). Its physical backgroud is the lossless
transmission line and microwave network. The basic idea of VTM is to insert
lossless transmission lines into the sparse linear system to achieve
distributed computing.
  VTM is proved to be convergent to solve SPD linear system. Preconditioning
method and performance model are presented. Numerical experiments show that VTM
is efficient, accurate and stable.
  Accompanied with VTM, we bring in a new technique to partition the symmetric
linear system, which is named Generalized Node & Branch Tearing (GNBT). It is
based on Kirchhoff's Current Law from circuit theory. We proved that GNBT is
feasible to partition any SPD linear system.


title: Support of Study on Engineering Technology from Physics and Mathematics

abstract:
  An approach that provides students with an ability to transfer learning in
physics and mathematics to the engineering-technology courses through
e-teaching and e-learning process is proposed. E-modules of courses in
mathematics, physics, computer systems technology, and electrical and
telecommunications engineering technology have been developed. These modules
being used in the Blackboard and Web-based communications systems create a
virtual interdisciplinary learning community, which helps the students to
transfer knowledge from physics and mathematics to their study in engineering
technology.


title: Phenomenological models of baryon

abstract:
  In this paper, I present almost my works performed during my time at VNU. I
was interested in the composite Skyrme model proposed by H. Y. Cheung and F.
Gursey. The expanding for this model based on results obtained from the
original Skyrme model given by T. H. R. Skyrme in 1961 was general and
interesting.


title:
Spontaneous Generation of Vortex Array Beams from a Thin-Slice
  Solid-State Laser with Wide-Aperture Laser-Diode Pumping

abstract:
  We studied complex lasing pattern formations in a thin-slice solid-state
laser with wide-aperture laser-diode end-pumping. Radial and rectangular vortex
arrays were found to be formed in a controlled fashion with symmetric and
asymmetric pump beam profiles, respectively. Most of these vortices exhibited
single-frequency oscillations arising from a spontaneous process of transverse
mode locking of nearly degenerate modes assisted by the laser nonlinearity.
Single-frequency rectangular array beams consisting of a large number of
vortices, e.g., closely packed 36 or 46 vortex pixels, were generated,
originating from Ince-Gaussian modes excited by the asymmetric pumping.


title:
Electronic structures of organic molecule encapsulated BN nanotubes
  under transverse electric field

abstract:
  The electronic structures of boron nitride nanotubes (BNNTs) doped by
different organic molecules under a transverse electric field were investigated
via first-principles calculations. The external field reduces the energy gap of
BNNT, thus makes the molecular bands closer to the BNNT band edges and enhances
the charge transfers between BNNT and molecules. The effects of the electric
field direction on the band structure are negligible. The electric field
shielding effect of BNNT to the inside organic molecules is discussed. Organic
molecule doping strongly modifies the optical property of BNNT, and the
absorption edge is red-shifted under static transverse electric field.


title: Influence of firing mechanisms on gain modulation

abstract:
  We studied the impact of a dynamical threshold on the f-I curve-the
relationship between the input and the firing rate of a neuron-in the presence
of background synaptic inputs. First, we found that, while the leaky
integrate-and-fire model cannot reproduce the f-I curve of a cortical neuron,
the leaky integrate-and-fire model with dynamical threshold can reproduce it
very well. Second, we found that the dynamical threshold modulates the onset
and the asymptotic behavior of the f-I curve. These results suggest that a
cortical neuron has an adaptation mechanism and that the dynamical threshold
has some significance for the computational properties of a neuron.


title: Summary of Experimental Results: Photons, Leptons and Heavy Quarks

abstract:
  This is a summary of experimental results on photons, leptons, and heavy
quarks presented at Quark Matter 2008. A first measurement of the bottom to
charm contribution to the lepton spectrum has given experimental indication for
the suppression of charm and bottom. Excess dileptons have been observed and
studied by both NA60 and PHENIX, which may arise from the early production of
thermal dileptons and/or the modification of mesons.


title: A possible common halo of the Magellanic Clouds

abstract:
  Recent observational and theoretical studies on the three-dimensional (3D)
space motions of the Large and the Small Magellanic Clouds (LMC and SMC,
respectively) have strongly suggested that the latest proper motion
measurements of the Magellanic Clouds (MCs) are consistent with their orbital
evolution models in which the MCs have arrived in the Galaxy quite recently for
the first time. The suggested orbital models appear to be seriously
inconsistent with the tidal interaction models in which the Magellanic Stream
(MS) can be formed as a result of the mutual tidal interaction between the MCs
and the Galaxy for the last ~2 Gyr. Based on orbital models of the MCs, we
propose that if the MCs have a common diffuse dark halo with the mass larger
than ~ 2 * 10^{10} M_sun, the MCs can not only have the present 3D velocities
consistent with the latest proper motion measurements but also interact
strongly with each other and with the Galaxy for the last 2 Gyr.These results
imply that if the observed proper motions of the MCs are true ones of the
centers of mass for the MCs, the common halo of the MCs would need to be
considered in constructing self-consistent MS formation models. We discuss
whether the origin of the possible common halo can be closely associated either
with the past binary formation or with the MCs having been in a small group.


title: Putting the Warp into Warp Drive

abstract:
  Over the last decade, there has been a respectable level of scientific
interest regarding the concept of a warp drive. This is a hypothetical
propulsion device that could theoretically circumvent the traditional
limitations of special relativity which restricts spacecraft to sub-light
velocities. Any breakthrough in this field would revolutionize space
exploration and open the doorway to interstellar travel. This article discusses
a novel approach to generating the warp bubble necessary for such propulsion;
the mathematical details of this theory are discussed in an article published
in the Journal of the British Interpanetary Society. The theory is based on
some of the exciting predictions coming out of string theory and it is the aim
of this article to introduce the warp drive idea from a non-mathematical
perspective that should be accessible to a wide range of readers.


title:
Rational symplectic coordinates on the space of Fuchs equations $m
  \times m$-case

abstract:
  A method of constructing of Darboux coordinates on a space that is a
symplectic reduction with respect to a diagonal action of $GL(m})$ on a
Cartesian product of $N$ orbits of coadjoint representation of $GL(m)$ is
presented. The method gives an explicit symplectic birational isomorphism
between the reduced space on the one hand and a Cartesian product of $N-3$
coadjoint orbits of dimension $m(m-1)$ on an orbit of dimension $(m-1)(m-2)$ on
the other hand. In a generic case of the diagonalizable matrices it gives just
the isomorphism that is birational and symplectic between some open, in a
Zariski topology, domain of the reduced space and the Cartesian product of the
orbits in question. The method is based on a Gauss decomposition of a matrix on
a product of upper-triangular, lower-triangular and diagonal matrices. It works
uniformly for the orbits formed by diagonalizable or not-diagonalizable
matrices. It is elaborated for the orbits of maximal dimension that is
$m(m-1)$.


title:
BOKASUN: a fast and precise numerical program to calculate the Master
  Integrals of the two-loop sunrise diagrams

abstract:
  We present the program BOKASUN for fast and precise evaluation of the Master
Integrals of the two-loop self-mass sunrise diagram for arbitrary values of the
internal masses and the external four-momentum. We use a combination of two
methods: a Bernoulli accelerated series expansion and a Runge-Kutta numerical
solution of a system of linear differential equations.


title: Cluster algebras, quiver representations and triangulated categories

abstract:
  This is an introduction to some aspects of Fomin-Zelevinsky's cluster
algebras and their links with the representation theory of quivers and with
Calabi-Yau triangulated categories. It is based on lectures given by the author
at summer schools held in 2006 (Bavaria) and 2008 (Jerusalem). In addition to
by now classical material, we present the outline of a proof of the periodicity
conjecture for pairs of Dynkin diagrams (details will appear elsewhere) and
recent results on the interpretation of mutations as derived equivalences.


title:
Phonon assisted dynamical Coulomb blockade in a thin suspended graphite
  sheet

abstract:
  The differential conductance in a suspended few layered graphene sample is
fou nd to exhibit a series of quasi-periodic sharp dips as a function of bias
at l ow temperature. We show that they can be understood within a simple model
of dyn amical Coulomb blockade where energy exchanges take place between the
charge carriers transmitted trough the sample and a dissipative electromagnetic
envir onment with a resonant phonon mode strongly coupled to the electrons.


title: Short Hard Gamma Ray Bursts And Their Afterglows

abstract:
  Long duration gamma ray bursts (GRBs) and X-ray flashes (XRFs) are produced
by highly- relativistic jets ejected in core-collapse supernova explosions. The
origin of short hard gamma-ray bursts (SHBs) has not been established. They may
be produced by highly relativistic jets ejected in various processes: mergers
of compact stellar objects; large-mass accretion episodes onto compact stars in
close binaries or onto intermediate-mass black holes in dense stellar regions;
phase transition of compact stars. Natural environments of such events are the
dense cores of globular clusters, superstar clusters and young supernova
remnants. We have used the cannonball model of GRBs to analyze all Swift SHBs
with a well-sampled X-ray afterglow. We show that their prompt gamma-ray
emission can be explained by inverse Compton scattering (ICS) of the
progenitor's glory light, and their extended soft emission component by ICS of
high density light or synchrotron radiation (SR) in a high density interstellar
medium within the cluster. The mechanism generating the afterglow is
synchrotron radiation outside the cluster. No associated supernova could be
detected in the low luminosity nearby GRBs 060614 and 060505. We interpret them
as SHBs seen relatively far off axis.


title:
Energy image density property and the lent particle method for Poisson
  measures

abstract:
  We introduce a new approach to absolute continuity of laws of Poisson
functionals. It is based on the {\it energy image density} property for
Dirichlet forms and on what we call {\it the lent particle method} which
consists in adding a particle and taking it back after some calculation.


title: The massless supersymmetric ladder with L rungs

abstract:
  We show that in the massless N=1 supersymmetric Wess-Zumino theory it is
possible to devise a computational strategy by which the x-space calculation of
the ladder 4-point correlators can be carried out without introducing any
regularization. As an application we derive a representation valid at all loop
orders in terms of conformal invariant integrals. We obtain an explicit
expression of the 3-loop ladder diagram for collinear external points.


title: Noether symmetry for non-minimally coupled fermion fields

abstract:
  A cosmological model where a fermion field is non-minimally coupled with the
gravitational field is studied. By applying Noether symmetry the possible
functions for the potential density of the fermion field and for the coupling
are determined. Cosmological solutions are found showing that the non-minimally
coupled fermion field behaves as an inflaton describing an accelerated
inflationary scenario, whereas the minimally coupled fermion field describes a
decelerated period being identified as dark matter.


title:
Wigner Distribution Functions and the Representation of Canonical
  Transformations in Time-Dependent Quantum Mechanics

abstract:
  For classical canonical transformations, one can, using the Wigner
transformation, pass from their representation in Hilbert space to a kernel in
phase space. In this paper it will be discussed how the time-dependence of the
uncertainties of the corresponding time-dependent quantum problems can be
incorporated into this formalism.


title: On the Real Multidimensional Rational K-Moment Problem

abstract:
  We present a solution to the real multidimensional rational K-moment problem,
where K is defined by finitely many polynomial inequalities. More precisely,
let S be a finite set of real polynomials in X=(X_1,...,X_n) such that the
corresponding basic closed semialgebraic set K_S is nonempty. Let E=D^{-1}R[X]
be a localization of the real polynomial algebra, and T_S^E the preordering on
E generated by S. We show that every linear functional L on E that is
nonnegative on T_S^E is represented by a positive measure on a certain subset
of K_S, provided D contains an element that grows fast enough on K_S.


title:
Empirically Consistent Electroweak Radiative Corrections with the
  Two-Higgs Doublet Model

abstract:
  The electroweak radiative correction, which turned out to be marginal within
the standard electroweak model having the minimal Higgs sector in view of the
present experimental information, fits well the experiment when the Higgs
sector is extended to have two Higgs doublets. We predict the range where the
charged and CP odd Higgs boson masses would lie, taking the two CP even neutral
Higgs boson masses to be degenerate which makes the analysis in multiparameter
space feasible. It is shown that the mass of neutral Higgs doublet boson can
arbitrarily be large consistently with the $W$ mass, if the charged Higgs boson
is present and it's mass lies in some appropriate ranges.


title:
Approximation for radiation power of electrons due to inverse-Compton
  process in the black-body photon field

abstract:
  An approximation for the inverse-Compton radiation power of electrons in the
isotropic black-body photon field is presented. The approximation allows one to
calculate inverse-Compton emissivity as integral over the energies of incident
electrons rather than over the field photon energies. Such an approach allows
for accurate modeling of IC emission of electrons with energy spectra being
different from power-law, in situation where the CPU resources are limited.
High accuracy of this approximation allows one to use it in a wide range of
conditions, from Thomson to extreme Klein-Nishina limits. The approach adopted
results also in some new analytic expressions representing known results in the
Thomson limit.


title: Diophantine sets of polynomials over number fields

abstract:
  Let R be a recursive subring of a number field. We show that recursively
enumerable sets are diophantine for the polynomial ring R[Z].


title:
The fourth family: a simple explanation for the observed pattern of
  anomalies in B-CP asymmetries

abstract:
  We show that a fourth family of quarks with $m_{t'}$ in the range of (400 -
600) GeV provides a rather simple explanation for the several indications of
new physics that have been observed involving CP asymmetries of the b-quark.
The built-in hierarchy of the 4$\times$4 mixing matrix is such that the $t'$
readily provides a needed {\it perturbation} ($\approx 15%$) to $\sin 2 \beta$
as measured in $B \to \psi K_s$ and simultaneously is the dominant source of CP
asymmetry in $B_s \to \psi \phi$. The correlation between CP asymmetries in
$B_s \to\psi \phi$ and $B_d\to\phi K_s$ suggests $m_{t'} \approx$ (400 - 600)
GeV. Such heavy masses point to the tantalizing possibility that the 4th family
plays an important role in the electroweak symmetry breaking.


title: On Scattering of Solitons for Maxwell Equation Coupled to a Particle

abstract:
  We establish long time soliton asymptotics for the nonlinear system of
Maxwell equations coupled to a charged particle. The coupled system has a six
dimensional manifold of soliton solutions. We show that in the long time
approximation, any solution, with an initial state close to the solitary
manifold, is a sum of a soliton and a dispersive wave which is a solution of
the free Maxwell equations. It is assumed that the charge density satisfies the
Wiener condition. The proof further develops the general strategy based on the
symplectic projection in Hilbert space onto the solitary manifold, modulation
equations for the parameters of the projection, and decay of the transversal
component.


title: Dark Matter Density in Disk Galaxies

abstract:
  I show that the predicted densities of the inner dark matter halos in LCDM
models of structure formation appear to be higher than estimates from real
galaxies and constraints from dynamical friction on bars. This inconsistency
would not be a problem for the LCDM model if physical processes that are
omitted in the collisionless collapse simulations were able to reduce the dark
matter density in the inner halos. I review the mechanisms proposed to achieve
the needed density reduction.


title: A 12CO, 13CO, and C18O Survey of Infrared Dark Clouds

abstract:
  InfraRed Dark Clouds (IRDCs) are extinction features against the Galactic
infrared background, mainly in mid-infrared band. Recently they were proposed
to be potential sites of massive star formation. In this work we have made
12CO, 13CO, and C18O (J=1-0) survey of 61 IRDCs, 52 of which are in the first
Galactic quadrant, selected from a catalog given by Simon et al. (2006), while
the others are in the outer Galaxy, selected by visually inspecting the MSX
images. Detection rates in the three CO lines are 90%, 71%, and 62%
respectively. The distribution of IRDCs in the first Galactic quadrant is
consistent with the 5 kpc molecular ring picture, while slight trace of spiral
pattern can also be noticed, which needs to be further examined. The IRDCs have
typical excitation temperature of 10 K and typical column density of several
10^{22} cm^{-2}. Their typical physical size is estimated to be several pcs
using angular sizes from the Simon catalog. Typical volume density and typical
LTE mass are ~5000 cm^{-3} and ~5000 M_{sun} respectively. The IRDCs are in or
near virial equilibrium. The properties of IRDCs are similar to those of star
forming molecular clumps, and they seem to be intermediate between giant
molecular clouds and Bok globules, thus they may represent early stages of
massive star formation.


title: An Upper Estimate for the Overpseudoprime Counting Function

abstract:
  We prove that the number of overpseudoprimes to base 2 not exceeding x does
not exceed x^(3/4)(1+o(1)).


title: Many-flavor electron gas approach to electron-hole drops

abstract:
  A many-flavor electron gas (MFEG) is analyzed, such as could be found in a
multi-valley semiconductor or semimetal. Using the re-derived polarizability
for the MFEG an exact expression for the total energy of a uniform MFEG in the
many-flavor approximation is found; the interacting energy per particle is
shown to be -0.574447E_h a_0^3/4 m*^3/4 n^1/4 with E_h being the Hartree
energy, a_0 Bohr radius, and m^* particle effective mass. The short
characteristic length-scale of the MFEG motivates a local density
approximation, allowing a gradient expansion in the energy density, and the
expansion scheme is applied to electron-hole drops, finding a new form for the
density profile and its surface scaling properties.


title:
Chiral-Odd Generalized Parton Distributions from Exclusive pi^o
  Electroproduction

abstract:
  Exclusive $\pi^o$ electroproduction is suggested for extracting both the
tensor charge and the transverse anomalous magnetic moment from experimental
data. A connection between partonic degrees of freedom, given in terms of
Generalized Parton Distributions, and Regge phenomenology is discussed.
Calculations are performed using a physically motivated parametrization that is
valid at values of the skewness, $\zeta \neq 0$. Our method makes use of
information from the nucleon form factor data, from deep inelastuc scattering
parton distribution functions, and from lattice results on the Mellin moments
of generalized parton distributions. It provides, therefore, a step towards a
model independent extraction of generalized distributions from the data,
alternative to other mathematical ansatze available in the literature.