title: "Illusion of control" in Minority and Parrondo Games

abstract:
  Human beings like to believe they are in control of their destiny. This
ubiquitous trait seems to increase motivation and persistence, and is probably
evolutionarily adaptive. But how good really is our ability to control? How
successful is our track record in these areas? There is little understanding of
when and under what circumstances we may over-estimate or even lose our ability
to control and optimize outcomes, especially when they are the result of
aggregations of individual optimization processes. Here, we demonstrate
analytically using the theory of Markov Chains and by numerical simulations in
two classes of games, the Minority game and the Parrondo Games, that agents who
optimize their strategy based on past information actually perform worse than
non-optimizing agents. In other words, low-entropy (more informative)
strategies under-perform high-entropy (or random) strategies. This provides a
precise definition of the "illusion of control" in set-ups a priori defined to
emphasize the importance of optimization.


title: Classification of Noncommuting Quadrilaterals of Factors

abstract:
  A quadrilateral of factors is an irreducible inclusion of factors $N \subset
M$ with intermediate subfactors $P$ and $Q$ such that $P$ and $Q$ generate $M$
and the intersection of $P$ and $Q$ is $N$. We investigate the structure of a
non-commuting quadrilateral of factors with all the elementary inclusions
$P\subset M$, $Q\subset M$, $N\subset P$, and $N\subset Q$ 2-supertransitive.
In particular we classify such quadrilaterals with the indices of the
elementary subfactors less than or equal to 4. We also compute the angles
between $P$ and $Q$ for quadrilaterals coming from $\alpha$-induction and
asymptotic inclusions.


title:
Investigation of Energy Spectrum of EGRET Gamma-ray Sources by an
  Extensive Air Shower Experiment

abstract:
  Ultra-High-Energy (UHE) ($E>100 $TeV) Extensive Air Showers (EASs) have been
monitored for a period of five years (1997-2003), using a small array of
scintillation detectors in Tehran, Iran. The data have been analyzed to take in
to account of the dependence of source counts on zenith angle. Because of
varying thickness of the overlaying atmosphere, the shower count rate is
extremely dependent on zenith angle. During a calendar year different sources
come in the field of view of the array at varying zenith angles and have
different effective observation time equivalent to zenith in a day. High energy
gamma-ray sources from the EGRET third catalogue where observed and the data
were analyzed using an excess method. Upper limits were obtained for 10 EGRET
sources. Then we investigated the EAS event rates for these 10 sources and
obtained a flux for each of them using parameters of our experiment results and
simulations. Finally we investigated the gamma-ray spectrum in the UHE range
using these fluxes with reported fluxes of the EGRET sources.


title:
Conjugate field and fluctuation-dissipation relation for the dynamic
  phase transition in the two-dimensional kinetic Ising model

abstract:
  The two-dimensional kinetic Ising model, when exposed to an oscillating
applied magnetic field, has been shown to exhibit a nonequilibrium,
second-order dynamic phase transition (DPT), whose order parameter Q is the
period-averaged magnetization. It has been established that this DPT falls in
the same universality class as the equilibrium phase transition in the
two-dimensional Ising model in zero applied field. Here we study for the first
time the scaling of the dynamic order parameter with respect to a nonzero,
period-averaged, magnetic `bias' field, H_b, for a DPT produced by a
square-wave applied field. We find evidence that the scaling exponent,
\delta_d, of H_b at the critical period of the DPT is equal to the exponent for
the critical isotherm, \delta_e, in the equilibrium Ising model. This implies
that H_b is a significant component of the field conjugate to Q. A finite-size
scaling analysis of the dynamic order parameter above the critical period
provides further support for this result. We also demonstrate numerically that,
for a range of periods and values of H_b in the critical region, a
fluctuation-dissipation relation (FDR), with an effective temperature
T_{eff}(T, P, H_0) depending on the period, and possibly the temperature and
field amplitude, holds for the variables Q and H_b. This FDR justifies the use
of the scaled variance of Q as a proxy for the nonequilibrium susceptibility,
\partial<Q> / \partial H_b, in the critical region.


title: Non-commutativity and Open Strings Dynamics in Melvin Universes

abstract:
  We compute the Moyal phase factor for open strings ending on D3-branes
wrapping a NSNS Melvin universe in a decoupling limit explicitly using world
sheet formalism in cylindrical coordinates.


title:
High Galactic Latitude Interstellar Neutral Hydrogen Structure and
  Associated (WMAP) High Frequency Continuum Emission

abstract:
  Spatial associations have been found between interstellar neutral hydrogen
(HI) emission morphology and small-scale structure observed by the Wilkinson
Microwave Anisotropy Probe (WMAP) in an area bounded by l = 60 & 180 deg, b =
30 & 70 deg, which was the primary target for this study. This area is marked
by the presence of highly disturbed local HI and a preponderance of
intermediate- and high-velocity gas. The HI distribution toward the brightest
peaks in the WMAP Internal Linear Combination (ILC) map for this area is
examined and by comparing with a second area on the sky it is demonstrated that
the associations do not appear to be the result of chance coincidence. Close
examination of several of the associations reveals important new properties of
diffuse interstellar neutral hydrogen structure. In the case of high-velocity
cloud MI, the HI and WMAP ILC morphologies are similar and an excess of soft
X-ray emission and H-alpha emission have been reported for this feature. It is
suggested that the small angular-scale, high frequency continuum emission
observed by WMAP may be produced at the surfaces of HI features interacting one
another, or at the interface between moving HI structures and regions of
enhanced plasma density in the surrounding interstellar medium. It is possible
that dust grains play a role in producing the emission. However, the primary
purpose of this report is to draw attention to these apparent associations
without offering an unambiguous explanation as to the relevant emission
mechanism(s).


title:
Negative- and positive-phase-velocity propagation in an isotropic chiral
  medium moving at constant velocity

abstract:
  Analysis of electromagnetic planewave propagation in a medium which is a
spatiotemporally homogeneous, temporally nonlocal, isotropic, chiral medium in
a co-moving frame of reference shows that the medium is both spatially and
temporally nonlocal with respect to all non-co-moving inertial frames of
reference. Using the Lorentz transformations of electric and magnetic fields,
we show that plane waves which have positive phase velocity in the co-moving
frame of reference can have negative phase velocity in certain non-co-moving
frames of reference. Similarly, plane waves which have negative phase velocity
in the co-moving frame can have positive phase velocity in certain
non-co-moving frames.


title:
Sensitivity of solar off-limb line profiles to electron density
  stratification and the velocity distribution anisotropy

abstract:
  The effect of the electron density stratification on the intensity profiles
of the H I Ly-$\alpha$ line and the O VI and Mg X doublets formed in solar
coronal holes is investigated. We employ an analytical 2-D model of the large
scale coronal magnetic field that provides a good representation of the corona
at the minimum of solar activity. We use the mass-flux conservation equation to
determine the outflow speed of the solar wind at any location in the solar
corona and take into account the integration along the line of sight (LOS). The
main assumption we make is that no anisotropy in the kinetic temperature of the
coronal species is considered. We find that at distances greater than 1 Rsun
from the solar surface the widths of the emitted lines of O VI and Mg X are
sensitive to the details of the adopted electron density stratification.
However, Ly-$\alpha$, which is a pure radiative line, is hardly affected. The
calculated total intensities of Ly-$\alpha$ and the O VI doublet depend to a
lesser degree on the density stratification and are comparable to the observed
ones for most of the considered density models. The widths of the observed
profiles of Ly-$\alpha$ and Mg X are well reproduced by most of the considered
electron density stratifications, while for the O VI doublet only few
stratifications give satisfying results. The densities deduced from SOHO data
result in O VI profiles whose widths and intensity ratio are relatively close
to the values observed by UVCS although only isotropic velocity distributions
are employed. These density profiles also reproduce the other considered
observables with good accuracy. Thus the need for a strong anisotropy of the
velocity distribution (i.e. a temperature anisotropy) is not so clear cut as
previous investigations of UVCS data suggested. ...


title: Subfactors and Hadamard Matrices

abstract:
  To any complex Hadamard matrix H one associates a spin model commuting
square, and therefore a hyperfinite subfactor. The standard invariant of this
subfactor captures certain "group-like" symmetries of H. To gain some insight,
we compute the first few relative commutants of such subfactors for Hadamard
matrices of small dimensions. Also, we show that subfactors arising from Dita
type matrices have intermediate subfactors, and thus their standard invariants
have some extra structure besides the Jones projections.


title:
SW Sextantis stars: the dominant population of CVs with orbital periods
  between 3-4 hours

abstract:
  [Abridged] We present time-series optical photometry of five new CVs
identified by the Hamburg Quasar Survey. The eclipses observed in HS 0129+2933,
HS 0220+0603, and HS 0455+8315 provided very accurate orbital periods of
3.35129827(65), 3.58098501(34), and 3.56937674(26) h, respectively. HS
0805+3822 shows grazing eclipses and has a likely orbital period of 3.2169(2)
h. Time-resolved optical spectroscopy of the new CVs (with the exception of HS
0805+3822) is also presented. Radial velocity studies provided an orbital
period of 3.55 h for HS 1813+6122, which allowed us to identify the observed
photometric signal at 3.39 h as a negative superhump wave. The spectroscopic
behaviour clearly identifies these new CVs as new SW Sextantis stars. These new
additions increase the number of known SW Sex stars to 35. Almost 40 per cent
of the total SW Sex population do not show eclipses, invalidating the
requirement of eclipses as a defining characteristic of the class and the
models based on a high orbital inclination geometry alone. On the other hand,
the predominance of orbital periods in the narrow 3-4.5 h range is becoming
more pronounced. In fact, almost half the CVs which populate the 3-4.5 h period
interval are definite members of the class. These statistics are confirmed by
our results from the Hamburg Quasar Survey CVs. Remarkably, 54 per cent of the
Hamburg nova-like variables have been identified as SW Sex stars with orbital
periods in the 3-4.5 h range. The observation of this pile-up of systems close
to the upper boundary of the period gap is difficult to reconcile with the
standard theory of CV evolution, as the SW Sex stars are believed to have the
highest mass transfer rates among CVs. Finally, we review the full range of
common properties that the SW Sex stars exhibit.


title: Relativeca Dopplera efekto \^ce unuforme akcelata movo -- II

abstract:
  Extending physics/0701092, a light source of monochromatic radiation, in
rectilinear motion under constant proper acceleration, passes near an observer
at rest. In the context of special relativity, we describe the observed Doppler
effect. We describe also the interesting discontinuous effect when riding
through occurs. An English version of this article is available.
  -----
  Da^urigante physics/0701092, luma fonto de unukolora radiado ^ce rekta movo
^ce konstanta propra akcelo pasas preter restanta observanto. ^Ce la
special-relativeco, ni priskribas la observatan Doppleran efikon. Ni anka^u
priskribas la interesan nekontinuan efikon se trapaso okazas.


title: Finding (or not) New Gamma-ray Pulsars with GLAST

abstract:
  Young energetic pulsars will likely be the largest class of Galactic sources
observed by GLAST, with many hundreds detected. Many will be unknown as radio
pulsars, making pulsation detection dependent on radio and/or x-ray
observations or on blind periodicity searches of the gamma-rays. Estimates for
the number of pulsars GLAST will detect in blind searches have ranged from tens
to many hundreds. I argue that the number will be near the low end of this
range, partly due to observations being made in a scanning as opposed to a
pointing mode. This paper briefly reviews how blind pulsar searches will be
conducted using GLAST, what limits these searches, and how the computations and
statistics scale with various parameters.


title: Did time begin? Will time end?

abstract:
  Did time begin at a Big Bang? Will the present expansion of the universe last
for a finite or infinite time? These questions sound philosophical but are
becoming, now in the twenty-first century, central to the scientific study of
cosmology. The answers, which should become clarified in the next decade or
two, could have profound implications for how we see our own role in the
universe. Since the original publication of Stephen Hawking's {\it A Brief
History of Time} in 1988, the answers to these questions have progressed as a
result of research by the community of active theoretical physicists including
myself. To present the underlying ideas requires discussion of a wide range of
topics in cosmology, especially the make up of the energy content of the
universe. A brief summary of my conclusions, that of three different
possibilities concerning the history and future of time, the least likely is
the conventional wisdom (time began and will never end) and most likely is a
cyclic model (time never begins or ends), is in the short final Chapter which
could be read first. To understand the reasoning leading to my conclusions
could encourage reading of my entire book. My hope in writing this, my first
popular book, is that it will engender reflection about time. Many a
non-scientist may already hold a philosophical opinion about whether time
begins and ends. This book's aim is to present some recently discovered
scientific facts which can focus the reader's consideration of the two short
questions in my title.


title:
FUSE Observations of the Dwarf Novae UU Aql, BV Cen, and CH UMa in
  Quiescence

abstract:
  We report on FUSE spectra of three U Gem-type, long period, dwarf novae, UU
Aql, BV Cen and CH UMa taken during their quiescence intervals. We discuss the
line identifications in their spectra and attempt to characterize the source(s)
of their FUV flux distribution. Archival IUE spectrum of CH UMa and BV Cen in
quiescence were identified as having a matching flux level with the FUSE
spectra and these were combined with each FUSE spectrum to broaden the
wavelength coverage and further constrain model fits. Multi-component synthetic
spectral fits from our model grids, consisting of single temperature white
dwarfs, two-temperature white dwarfs, accretion disks and white dwarfs plus
accretion disks, were applied to the FUSE spectra alone and to the combined
FUSE + IUE spectra. We present the results of our model analyses and their
implications.


title:
Experimental and theoretical study of light scattering by individual
  mature red blood cells by use of scanning flow cytometry and discrete dipole
  approximation

abstract:
  Elastic light scattering by mature red blood cells (RBCs) was theoretically
and experimentally analyzed with the discrete dipole approximation (DDA) and
the scanning flow cytometry (SFC), respectively. SFC permits measurement of
angular dependence of light-scattering intensity (indicatrix) of single
particles. A mature RBC is modeled as a biconcave disk in DDA simulations of
light scattering. We have studied the effect of RBC orientation related to the
direction of the incident light upon the indicatrix. Numerical calculations of
indicatrices for several aspect ratios and volumes of RBC have been carried
out. Comparison of the simulated indicatrices and indicatrices measured by SFC
showed good agreement, validating the biconcave disk model for a mature RBC. We
simulated the light-scattering output signals from the SFC with the DDA for
RBCs modeled as a disk-sphere and as an oblate spheroid. The biconcave disk,
the disk-sphere, and the oblate spheroid models have been compared for two
orientations, i.e. face-on and rim-on incidence. Only the oblate spheroid model
for rim-on incidence gives results similar to the rigorous biconcave disk
model.


title:
Inflation, bifurcations of nonlinear curvature Lagrangians and dark
  energy

abstract:
  A possible equivalence of scalar dark matter, the inflaton, and modified
gravity is analyzed. After a conformal mapping, the dependence of the effective
Lagrangian on the curvature is not only singular but also bifurcates into
several almost Einsteinian spaces, distinguished only by a different effective
gravitational strength and cosmological constant. A swallow tail catastrophe in
the bifurcation set indicates the possibility for the coexistence of different
Einsteinian domains in our Universe. This `triple unification' may shed new
light on the nature and large scale distribution not only of dark matter but
also on `dark energy', regarded as an effective cosmological constant, and
inflation.


title: Stability of Chaplygin gas thin-shell wormholes

abstract:
  In this paper we construct spherical thin-shell wormholes supported by a
Chaplygin gas. For a rather general class of geometries we introduce a new
approach for the stability analysis of static solutions under perturbations
preserving the symmetry. We apply this to wormholes constructed from
Schwarzschild, Schwarzschild-de Sitter, Schwarzschild-anti de Sitter and
Reissner-Nordstrom metrics. In the last two cases, we find that there are
values of the parameters for which stable static solutions exist.


title:
Lattice refining loop quantum cosmology, anisotropic models and
  stability

abstract:
  A general class of loop quantizations for anisotropic models is introduced
and discussed, which enhances loop quantum cosmology by relevant features seen
in inhomogeneous situations. The main new effect is an underlying lattice which
is being refined during dynamical changes of the volume. In general, this leads
to a new feature of dynamical difference equations which may not have constant
step-size, posing new mathematical problems. It is discussed how such models
can be evaluated and what lattice refinements imply for semiclassical behavior.
Two detailed examples illustrate that stability conditions can put strong
constraints on suitable refinement models, even in the absence of a fundamental
Hamiltonian which defines changes of the underlying lattice. Thus, a large
class of consistency tests of loop quantum gravity becomes available. In this
context, it will also be seen that quantum corrections due to inverse powers of
metric components in a constraint are much larger than they appeared recently
in more special treatments of isotropic, free scalar models where they were
artificially suppressed.


title: Testing Disk Instability Models for Giant Planet Formation

abstract:
  Disk instability is an attractive yet controversial means for the rapid
formation of giant planets in our solar system and elsewhere. Recent concerns
regarding the first adiabatic exponent of molecular hydrogen gas are addressed
and shown not to lead to spurious clump formation in the author's disk
instability models. A number of disk instability models have been calculated in
order to further test the robustness of the mechanism, exploring the effects of
changing the pressure equation of state, the vertical temperature profile, and
other parameters affecting the temperature distribution. Possible reasons for
differences in results obtained by other workers are discussed. Disk
instability remains as a plausible formation mechanism for giant planets.


title: High-dimensional variable selection

abstract:
  This paper explores the following question: what kind of statistical
guarantees can be given when doing variable selection in high-dimensional
models? In particular, we look at the error rates and power of some multi-stage
regression methods. In the first stage we fit a set of candidate models. In the
second stage we select one model by cross-validation. In the third stage we use
hypothesis testing to eliminate some variables. We refer to the first two
stages as "screening" and the last stage as "cleaning." We consider three
screening methods: the lasso, marginal regression, and forward stepwise
regression. Our method gives consistent variable selection under certain
conditions.


title: Depletion effects in smectic phases of hard rod--hard sphere mixtures

abstract:
  It is known that when hard spheres are added to a pure system of hard rods
the stability of the smectic phase may be greatly enhanced, and that this
effect can be rationalised in terms of depletion forces. In the present paper
we first study the effect of orientational order on depletion forces in this
particular binary system, comparing our results with those obtained adopting
the usual approximation of considering the rods parallel and their orientations
frozen. We consider mixtures with rods of different aspect ratios and spheres
of different diameters, and we treat them within Onsager theory. Our results
indicate that depletion effects, and consequently smectic stability, decrease
significantly as a result of orientational disorder in the smectic phase when
compared with corresponding data based on the frozen--orientation
approximation. These results are discussed in terms of the $\tau$ parameter,
which has been proposed as a convenient measure of depletion strength. We
present closed expressions for $\tau$, and show that it is intimately connected
with the depletion potential. We then analyse the effect of particle geometry
by comparing results pertaining to systems of parallel rods of different shapes
(spherocylinders, cylinders and parallelepipeds). We finally provide results
based on the Zwanzig approximation of a Fundamental--Measure
density--functional theory applied to mixtures of parallelepipeds and cubes of
different sizes. In this case, we show that the $\tau$ parameter exhibits a
linear asymptotic behaviour in the limit of large values of the hard--rod
aspect ratio, in conformity with Onsager theory, as well as in the limit of
large values of the ratio of rod breadth to cube side length, $d$, in contrast
to Onsager approximation, which predicts $\tau\sim d^3$.


title: In Search of the Spacetime Torsion

abstract:
  Whether torsion plays or not a role in the description of the gravitational
interaction is a problem that can only be solved by experiment. This is,
however, a difficult task: since there are different possible interpretations
for torsion, there is no a model-independent way to look for it. In these
notes, two different possibilities will be reviewed, their consistency
analyzed, and the corresponding experimental outputs briefly discussed.


title: Observations of chemical differentiation in clumpy molecular clouds

abstract:
  We have extensively mapped a sample of dense molecular clouds (L1512, TMC-1C,
L1262, Per 7, L1389, L1251E) in lines of HC3N, CH3OH, SO and C^{18}O. We
demonstrate that a high degree of chemical differentiation is present in all of
the observed clouds. We analyse the molecular maps for each cloud,
demonstrating a systematic chemical differentiation across the sample, which we
relate to the evolutionary state of the cloud. We relate our observations to
the cloud physical, kinematical and evolutionary properties, and also compare
them to the predictions of simple chemical models. The implications of this
work for understanding the origin of the clumpy structures and chemical
differentiation observed in dense clouds are discussed.


title: Challenges for MSSM Higgs searches at Hadron Colliders

abstract:
  In this article we analyze the impact of B-physics and Higgs physics at LEP
on standard and non-standard Higgs bosons searches at the Tevatron and the LHC,
within the framework of minimal flavor violating supersymmetric models. The
B-physics constraints we consider come from the experimental measurements of
the rare B-decays b -> s gamma and B_u -> tau nu and the experimental limit on
the B_s -> mu+ mu- branching ratio. We show that these constraints are severe
for large values of the trilinear soft breaking parameter A_t, rendering the
non-standard Higgs searches at hadron colliders less promising. On the contrary
these bounds are relaxed for small values of A_t and large values of the
Higgsino mass parameter mu, enhancing the prospects for the direct detection of
non-standard Higgs bosons at both colliders. We also consider the available
ATLAS and CMS projected sensitivities in the standard model Higgs search
channels, and we discuss the LHC's ability in probing the whole MSSM parameter
space. In addition we also consider the expected Tevatron collider
sensitivities in the standard model Higgs h -> b bbar channel to show that it
may be able to find 3 sigma evidence in the B-physics allowed regions for small
or moderate values of the stop mixing parameter.


title: Optimization in Gradient Networks

abstract:
  Gradient networks can be used to model the dominant structure of complex
networks. Previous works have focused on random gradient networks. Here we
study gradient networks that minimize jamming on substrate networks with
scale-free and Erd\H{o}s-R\'enyi structure. We introduce structural
correlations and strongly reduce congestion occurring on the network by using a
Monte Carlo optimization scheme. This optimization alters the degree
distribution and other structural properties of the resulting gradient
networks. These results are expected to be relevant for transport and other
dynamical processes in real network systems.


title:
Fermionic construction of partition function for multi-matrix models and
  multi-component TL hierarchy

abstract:
  We use $p$-component fermions $(p=2,3,...)$ to present $(2p-2)N$-fold
integrals as a fermionic expectation value. This yields fermionic
representation for various $(2p-2)$-matrix models. Links with the $p$-component
KP hierarchy and also with the $p$-component TL hierarchy are discussed. We
show that the set of all (but two) flows of $p$-component TL changes standard
matrix models to new ones.


title: The Plasma Puddle as a Perturbative Black Hole

abstract:
  We argue that the weak coupling regime of a large N gauge theory in the Higgs
phase contains black hole-like objects. These so-called ``plasma puddles'' are
meta-stable lumps of hot plasma lying in locally un-Higgsed regions of space.
They decay via O(1/N) thermal radiation and, perhaps surprisingly, absorb all
incident matter. We show that an incident particle of energy E striking the
plasma puddle will shower into an enormous number of decay products whose
multiplicity grows linearly with E, and whose average energy is independent of
E. Once these ultra-soft particles reach the interior they are thermalized by
the plasma within, and so the object appears ``black.'' We determine some gross
properties like the size and temperature of the the plasma puddle in terms of
fundamental parameters in the gauge theory. Interestingly, demanding that the
plasma puddle emit thermal Hawking radiation implies that the object is black
(i.e. absorbs all incident particles), which implies classical stability, which
implies satisfaction of the Bekenstein entropy bound. Because of the AdS/CFT
duality and the many similarities between plasma puddles and black holes, we
conjecture that black objects are a robust feature of quantum gravity.


title: Information, complexity, brains and reality (Kolmogorov Manifesto)

abstract:
  I discuss several aspects of information theory and its relationship to
physics and neuroscience. The unifying thread of this somewhat chaotic essay is
the concept of Kolmogorov or algorithmic complexity (Kolmogorov Complexity, for
short). I argue that it is natural to interpret cognition as the art of finding
algorithms that apprach the Solomonoff-Kolmogorov-Chaitin (algorithmic)
Complexity limit with appropriate tradeoffs. In addition, I claim that what we
call the universe is an interpreted abstraction--a mental construct--based on
the observed coherence between multiple sensory input streams and our own
interactions. Hence, the notion of Universe is itself a model.


title:
Aspects of stochastic resonance in reaction-diffusion systems: The
  nonequilibrium-potential approach

abstract:
  We analyze several aspects of the phenomenon of stochastic resonance in
reaction-diffusion systems, exploiting the nonequilibrium potential's
framework. The generalization of this formalism (sketched in the appendix) to
extended systems is first carried out in the context of a simplified scalar
model, for which stationary patterns can be found analytically. We first show
how system-size stochastic resonance arises naturally in this framework, and
then how the phenomenon of array-enhanced stochastic resonance can be further
enhanced by letting the diffusion coefficient depend on the field. A yet less
trivial generalization is exemplified by a stylized version of the
FitzHugh-Nagumo system, a paradigm of the activator-inhibitor class. After
discussing for this system the second aspect enumerated above, we derive from
it -through an adiabatic-like elimination of the inhibitor field- an effective
scalar model that includes a nonlocal contribution. Studying the role played by
the range of the nonlocal kernel and its effect on stochastic resonance, we
find an optimal range that maximizes the system's response.


title: Distortion of Gravitational-Wave Packets Due to their Self-Gravity

abstract:
  When a source emits a gravity-wave (GW) pulse over a short period of time,
the leading edge of the GW signal is redshifted more than the inner boundary of
the pulse. The GW pulse is distorted by the gravitational effect of the
self-energy residing in between these shells. We illustrate this distortion for
GW pulses from the final plunge of black hole (BH) binaries, leading to the
evolution of the GW profile as a function of the radial distance from the
source. The distortion depends on the total GW energy released and the duration
of the emission, scaled by the total binary mass, M. The effect should be
relevant in finite box simulations where the waveforms are extracted within a
radius of <~ 100M. For characteristic emission parameters at the final plunge
between binary BHs of arbitrary spins, this effect could distort the simulated
GW templates for LIGO and LISA by a fraction of 0.001. Accounting for the wave
distortion would significantly decrease the waveform extraction errors in
numerical simulations.


title:
Fermionic approach to the evaluation of integrals of rational symmetric
  functions

abstract:
  We use the fermionic construction of two-matrix model partition functions to
evaluate integrals over rational symmetric functions. This approach is
complementary to the one used in the paper ``Integrals of Rational Symmetric
Functions, Two-Matrix Models and Biorthogonal Polynomials'' \cite{paper2},
where these integrals were evaluated by a direct method.


title:
Old Main-Sequence Turnoff Photometry in the Small Magellanic Cloud. I.
  Constraints on the Star Formation History in Different Fields

abstract:
  We present ground-based B and R-band color-magnitude diagrams (CMDs),
reaching the oldest main-sequence turnoffs with good photometric accuracy for
twelve fields in the Small Magellanic Cloud (SMC). Our fields, located between
~1 and ~4 degrees from the center of the galaxy, are situated in different
parts of the SMC such as the "Wing'' area, and towards the West and South. In
this paper we perform a first analysis of the stellar content in our SMC fields
through comparison with theoretical isochrones and color functions (CFs). We
find that the underlying spheroidally distributed population is composed of
both intermediate-age and old stars and that its age composition does not show
strong galacto-centric gradients. The three fields situated toward the east, in
the Wing region, show very active current star formation. However, only in the
eastern field closest to the center do we find an enhancement of recent star
formation with respect to a constant SFR(t). The fields corresponding to the
western side of the SMC present a much less populated young MS, and the CF
analysis indicates that the SFR(t) greatly diminished around 2 Gyr ago in these
parts. Field smc0057, the closest to the center of the galaxy and located in
the southern part, shows recent star formation, while the rest of the southern
fields present few bright MS stars. The structure of the red clump in all the
CMDs is consistent with the large amount of intermediate-age stars inferred
from the CMDs and color functions. None of the SMC fields presented here are
dominated by old stellar populations, a fact that is in agreement with the lack
of a conspicuous horizontal branch in all these SMC CMDs. This could indicate
that a disk population is ruling over a possible old halo in all the observed
fields.


title: Curvature perturbations from ekpyrotic collapse with multiple fields

abstract:
  A scale-invariant spectrum of isocurvature perturbations is generated during
collapse in the ekpyrotic scaling solution in models where multiple fields have
steep negative exponential potentials. The scale invariance of the spectrum is
realized by a tachyonic instability in the isocurvature field. This instability
drives the scaling solution to the late time attractor that is the old
ekpyrotic collapse dominated by a single field. We show that the transition
from the scaling solution to the single field dominated ekpyrotic collapse
automatically converts the initial isocurvature perturbations about the scaling
solution to comoving curvature perturbations about the late-time attractor. The
final amplitude of the comoving curvature perturbation is determined by the
Hubble scale at the transition.


title: Asymmetric Di-jet Production in Polarized Hadronic Collisions

abstract:
  Using the collinear QCD factorization approach, we study the
single-transverse-spin dependent cross section Delta sigma(S_perp) for the
hadronic production of two jets of momenta P_1=P+q/2 and P_2=-P+q/2. We
consider the kinematic region where the transverse components of the momentum
vectors satisfy P_perp >> q_perp >> Lambda_QCD. For the case of initial-state
gluon radiation, we show that at the leading power in q_perp/P_perp and at the
lowest non-trivial perturbative order, the dependence of Delta sigma(S_perp) on
q_perp decouples from that on P_perp, so that the cross section can be
factorized into a hard part that is a function only of the single scale P_perp,
and into perturbatively generated transverse-momentum dependent (TMD) parton
distributions with transverse momenta k_perp = O(q_perp).


title: Information, information processing and gravity

abstract:
  I discuss fundamental limits placed on information and information processing
by gravity. Such limits arise because both information and its processing
require energy, while gravitational collapse (formation of a horizon or black
hole) restricts the amount of energy allowed in a finite region. Specifically,
I use a criterion for gravitational collapse called the hoop conjecture. Once
the hoop conjecture is assumed a number of results can be obtained directly:
the existence of a fundamental uncertainty in spatial distance of order the
Planck length, bounds on information (entropy) in a finite region, and a bound
on the rate of information processing in a finite region. In the final section
I discuss some cosmological issues related to the total amount of information
in the universe, and note that almost all detailed aspects of the late universe
are determined by the randomness of quantum outcomes. This paper is based on a
talk presented at a 2007 Bellairs Research Institute (McGill University)
workshop on black holes and quantum information.


title:
Noise-induced phase transitions: Effects of the noises' statistics and
  spectrum

abstract:
  The local, uncorrelated multiplicative noises driving a second-order, purely
noise-induced, ordering phase transition (NIPT) were assumed to be Gaussian and
white in the model of [Phys. Rev. Lett. \textbf{73}, 3395 (1994)]. The
potential scientific and technological interest of this phenomenon calls for a
study of the effects of the noises' statistics and spectrum. This task is
facilitated if these noises are dynamically generated by means of stochastic
differential equations (SDE) driven by white noises. One such case is that of
Ornstein--Uhlenbeck noises which are stationary, with Gaussian pdf and a
variance reduced by the self-correlation time (\tau), and whose effect on the
NIPT phase diagram has been studied some time ago. Another such case is when
the stationary pdf is a (colored) Tsallis' (q)--\emph{Gaussian} which, being a
\emph{fat-tail} distribution for (q>1) and a \emph{compact-support} one for
(q<1), allows for a controlled exploration of the effects of the departure from
Gaussian statistics. As done before with stochastic resonance and other
phenomena, we now exploit this tool to study--within a simple mean-field
approximation and with an emphasis on the \emph{order parameter} and the
``\emph{susceptibility}''--the combined effect on NIPT of the noises'
statistics and spectrum. Even for relatively small (\tau), it is shown that
whereas fat-tail noise distributions ((q>1)) counteract the effect of
self-correlation, compact-support ones ((q<1)) enhance it. Also, an interesting
effect on the susceptibility is seen in the last case.


title: The Mid-Infrared Emission of M87

abstract:
  We discuss Subaru and Spitzer Space Telescope imaging and spectroscopy of M87
in the mid-infrared from 5-35 um. These observations allow us to investigate
mid-IR emission mechanisms in the core of M87 and to establish that the
flaring, variable jet component HST-1 is not a major contributor to the mid-IR
flux. The Spitzer data include a high signal-to-noise 15-35 $\mu$m spectrum of
the knot A/B complex in the jet, which is consistent with synchrotron emission.
However, a synchrotron model cannot account for the observed {\it nuclear}
spectrum, even when contributions from the jet, necessary due to the degrading
of resolution with wavelength, are included. The Spitzer data show a clear
excess in the spectrum of the nucleus at wavelengths longer than 25 um, which
we model as thermal emission from cool dust at a characteristic temperature of
55 \pm 10 K, with an IR luminosity \sim 10^{39} {\rm ~erg ~s^{-1}}. Given
Spitzer's few-arcsecond angular resolution, the dust seen in the nuclear
spectrum could be located anywhere within ~5'' (390 pc) of the nucleus. In any
case, the ratio of AGN thermal to bolometric luminosity indicates that M87 does
not contain the IR-bright torus that classical unified AGN schemes invoke.
However, this result is consistent with theoretical predictions for
low-luminosity AGNs


title: Fermionic construction of tau functions and random processes

abstract:
  Tau functions expressed as fermionic expectation values are shown to provide
a natural and straightforward description of a number of random processes and
statistical models involving hard core configurations of identical particles on
the integer lattice, like a discrete version simple exclusion processes (ASEP),
nonintersecting random walkers, lattice Coulomb gas models and others, as well
as providing a powerful tool for combinatorial calculations involving paths
between pairs of partitions. We study the decay of the initial step function
within the discrete ASEP (d-ASEP) model as an example.

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


title: Novelty and Collective Attention

abstract:
  The subject of collective attention is central to an information age where
millions of people are inundated with daily messages. It is thus of interest to
understand how attention to novel items propagates and eventually fades among
large populations. We have analyzed the dynamics of collective attention among
one million users of an interactive website -- \texttt{digg.com} -- devoted to
thousands of novel news stories. The observations can be described by a
dynamical model characterized by a single novelty factor. Our measurements
indicate that novelty within groups decays with a stretched-exponential law,
suggesting the existence of a natural time scale over which attention fades.


title: Characterization of open cluster remnants

abstract:
  Despite progress in the theoretical knowledge of open cluster remnants and
the growing search for observational identifications in recent years, open
questions still remain. The methods used to analyze open cluster remnants and
criteria to define them as physical systems are not homogeneous. In this work
we present a systematic method for studying these objects that provides a view
of their properties and allows their characterization. Eighteen remnant
candidates are analyzed by means of photometric and proper motion data. These
data provide information on objects and their fields. We establish criteria for
characterizing open cluster remnants, taking observational uncertainties into
account. 2MASS J and H photometry is employed (i) to study structural
properties of the objects by means of radial stellar density profiles, (ii) to
test for any similarity between objects and fields with a statistical
comparison method applied to the distributions of stars in the CMDs, and (iii)
to obtain ages, reddening values, and distances from the CMD, taking an index
of isochrone fit into account. The UCAC2 proper motions allowed an objective
comparison between objects and large solid angle offset fields. The objective
analysis based on the present methods indicates 13 open-cluster remnants in the
sample. Evidence of the presence of binary stars is found, as expected for
dynamically evolved systems. Finally, we infer possible evolutionary stages
among remnants from the structure, proper motion, and CMD distributions. The
low stellar statistics for individual objects is overcome by means of the
construction of composite proper motion and CMD diagrams. The distributions of
remnants in the composite diagrams resemble the single-star and unresolved
binary star distributions of open clusters.


title: Hall conductivity from dyonic black holes

abstract:
  A class of strongly interacting 2+1 dimensional conformal field theories in a
transverse magnetic field can be studied using the AdS/CFT duality. We compute
zero momentum hydrodynamic response functions of maximally supersymmetric 2+1
dimensional SU(N) Yang-Mills theory at the conformal fixed point, in the large
N limit. With background magnetic field B and electric charge density rho, the
Hall conductivity is found to be rho/B. The result, anticipated on kinematic
grounds in field theory, is obtained from perturbations of a four dimensional
AdS black hole with both electric and magnetic charges.


title:
The Fincher-Burke spin excitations and omega/T scaling in the insulating
  5% Sr-doped La2CuO4

abstract:
  Insulating La1.95Sr0.05CuO4 shares with superconducting cuprates the same
Fincher-Burke-like spin excitations, which usually are observed in itinerant
antiferromagnets. The local spectral function satisfies omega/T scaling above
~16 K for this incommensurate insulating cuprate. Together with previous
results in commensurate insulating and incommensurate superconducting cuprates,
these results further support the general scaling prediction for square-lattice
quantum spin S=1/2 systems. The width of incommensurate peaks in
La1.95Sr0.05CuO4 scales to a similar finite value as at optimal doping,
strongly suggesting that they are similarly distant from a quantum critical
point. They might both be limited to a finite correlation length by the partial
spin-glass freezing.


title: Binary Capture Rates for Massive Protostars

abstract:
  The high multiplicity of massive stars in dense, young clusters is
established early in their evolution. The mechanism behind this remains
unresolved. Recent results suggest that massive protostars may capture
companions through disk interactions with much higher efficiency than their
solar mass counterparts. However, this conclusion is based on analytic
determinations of capture rates and estimates of the robustness of the
resulting binaries. We present the results of coupled n-body and SPH
simulations of star-disk encounters to further test the idea that disk-captured
binaries contribute to the observed multiplicity of massive stars.


title:
Sharp Asymptotics for KPP Pulsating Front Speed-up and Diffusion
  Enhancement by Flows

abstract:
  We study KPP pulsating front speed-up and effective diffusivity enhancement
by general periodic incompressible flows. We prove the existence of and
determine the limits $c^*(A)/A$ and $D(A)/A^2$ as $A\to\infty$, where $c^*(A)$
is the minimal front speed and $D(A)$ the effective diffusivity.


title: Pulsating Front Speed-up and Quenching of Reaction by Fast Advection

abstract:
  We consider reaction-diffusion equations with combustion-type non-linearities
in two dimensions and study speed-up of their pulsating fronts by general
periodic incompressible flows with a cellular structure. We show that the
occurence of front speed-up in the sense $\lim_{A\to\infty} c_*(A)=\infty$,
with $A$ the amplitude of the flow and $c_*(A)$ the (minimal) front speed, only
depends on the geometry of the flow and not on the reaction function. In
particular, front speed-up happens for KPP reactions if and only if it does for
ignition reactions. We also show that the flows which achieve this speed-up are
precisely those which, when scaled properly, are able to quench any ignition
reaction.


title: Electroweak Higgs as a pseudo-Goldstone boson of broken scale invariance

abstract:
  We point out that it is possible to associate the electroweak Higgs boson
with the pseudo-Goldstone boson of broken scale invariance, thus resolving the
hierarchy problem in a technically natural way. We illustrate this idea with
two specific gauge models. Besides being consistent with all currently
available experimental data, both models maintain the predictive power of the
standard model, since the first model has only one additional parameter beyond
the standard model, and the second has the same number of free parameters as
the standard model.


title:
A linear reformulation of the Kuramoto model of self-synchronizing
  oscillators

abstract:
  The present paper introduces a linear reformulation of the Kuramoto model
describing a self-synchronizing phase transition in a system of globally
coupled oscillators that in general have different characteristic frequencies.
The reformulated model provides an alternative coherent framework through which
one can analytically tackle synchronization problems that are not amenable to
the original Kuramoto analysis. It allows one to solve explicitly for the
synchronization order parameter and the critical point of 1) the full
phase-locking transition for a system with a finite number of oscillators
(unlike the original Kuramoto model, which is solvable implicitly only in the
mean-field limit) and 2) a new class of continuum systems. It also makes it
possible to probe the system's dynamics as it moves towards a steady state.
While discussion in this paper is restricted to systems with global coupling,
the new formalism introduced by the linear reformulation also lends itself to
solving systems that exhibit local or asymmetric coupling.


title: Electron Transport in Nanogranular Ferromagnets

abstract:
  We study electronic transport properties of ferromagnetic nanoparticle arrays
and nanodomain materials near the Curie temperature in the limit of weak
coupling between the grains. We calculate the conductivity in the Ohmic and
non-Ohmic regimes and estimate the magnetoresistance jump in the resistivity at
the transition temperature. The results are applicable for many emerging
materials, including artificially self-assembled nanoparticle arrays and a
certain class of manganites, where localization effects within the clusters can
be neglected.


title:
Electronic Properties of Carbon Nanotubes Calculated from Density
  Functional Theory and the Empirical pi-Bond Model

abstract:
  The validity of the DFT models implemented by FIREBALL for CNT electronic
device modeling is assessed. The effective masses, band gaps, and transmission
coefficients of semi-conducting, zigzag, (n,0) carbon nanotubes (CNTs)
resulting from the ab initio tight-binding density functional theory (DFT) code
FIREBALL and the empirical, nearest-neighbor pi-bond model are compared for all
semiconducting n values 5 <(=) n <(=) 35. The DFT values for the effective
masses differ from the pi-bond values by +(-) 9% over the range of n values, 17
<(=) n <(=) 29, most important for electronic device applications. Over the
range 13 <(=) n <(=) 35, the DFT bandgaps are less than the empirical bandgaps
by 20-180 meV depending on the functional and the n value. The pi-bond model
gives results that differ signifcantly from the DFT results when the CNT
diameter goes below 1 nm due to the large curvature of the CNT. The pi-bond
model quickly becomes inaccurate away from the bandedges for a (10, 0) CNT, and
it is completely inaccurate for n <(=) 8.


title: Holographic bound and protein linguistics

abstract:
  The holographic bound in physics constrains the complexity of life. The
finite storage capability of information in the observable universe requires
the protein linguistics in the evolution of life. We find that the evolution of
genetic code determines the variance of amino acid frequencies and genomic GC
content among species. The elegant linguistic mechanism is confirmed by the
experimental observations based on all known entire proteomes.


title: Externally-polluted white dwarfs with dust disks

abstract:
  We report Spitzer Space Telescope photometry of eleven externally-polluted
white dwarfs. Of the nine stars for which we have IRAC photometry, we find that
GD 40, GD 133 and PG 1015+161 each has an infrared excess that can be
understood as arising from a flat, opaque, dusty disk. GD 56 also has an
infrared excess characteristic of circumstellar dust, but a flat-disk model
cannot reproduce the data unless there are grains as warm as 1700 K and perhaps
not even then. Our data support the previous suggestion that the metals in the
atmosphere of GD 40 are the result of accretion of a tidally-disrupted asteroid
with a chondritic composition.


title:
Highly synchronized noise-driven oscillatory behavior of a
  FitzHugh-Nagumo ring with phase-repulsive coupling

abstract:
  We investigate a ring of $N$ FitzHugh--Nagumo elements coupled in
\emph{phase-repulsive} fashion and submitted to a (subthreshold) common
oscillatory signal and independent Gaussian white noises. This system can be
regarded as a reduced version of the one studied in [Phys. Rev. E \textbf{64},
041912 (2001)], although externally forced and submitted to noise. The
noise-sustained synchronization of the system with the external signal is
characterized.


title: Disentanglement in a quantum critical environment

abstract:
  We study the dynamical process of disentanglement of two qubits and two
qutrits coupled to an Ising spin chain in a transverse field, which exhibits a
quantum phase transition. We use the concurrence and negativity to quantify
entanglement of two qubits and two qutrits, respectively. Explicit connections
between the concurrence (negativity) and the decoherence factors are given for
two initial states, the pure maximally entangled state and the mixed Werner
state. We find that the concurrence and negativity decay exponentially with
fourth power of time in the vicinity of critical point of the environmental
system.


title:
The Deviation of the Vacuum Refractive Index Induced by a Static
  Gravitational Field

abstract:
  We analyzed the influence of static gravitational field on the vacuum and
proposed the concept of inhomogeneous vacuum. According to the observational
result of the light deflection in solar gravitational field as well as the
corresponding Fermat's principle in the general relativity, we derived an
analytical expression of the refractive index of vacuum in a static
gravitational field. We found that the deviation of the vacuum refractive index
is composed of two parts: one is caused by the time dilation effect, the other
is caused by the length contraction effect. As an application, we simulated the
effect of the gravitational lensing through computer programming and found that
the missing central imaging could be interpreted in a reasonable way.


title: Deaconstructing Functions on Quadratic Surfaces into Multipoles

abstract:
  Any homogeneous polynomial $P(x, y, z)$ of degree $d$, being restricted to a
unit sphere $S^2$, admits essentially a unique representation of the form
$\lambda + \sum_{k = 1}^d [\prod_{j = 1}^k L_{kj}]$, where $L_{kj}$'s are
linear forms in $x, y$ and $z$ and $\lambda$ is a real number. The coefficients
of these linear forms, viewed as 3D vectors, are called \emph{multipole}
vectors of $P$. In this paper we consider similar multipole representations of
polynomial and analytic functions on other quadratic surfaces $Q(x, y, z) = c$,
real and complex. Over the complex numbers, the above representation is not
unique, although the ambiguity is essentially finite. We investigate the
combinatorics that depicts this ambiguity. We link these results with some
classical theorems of harmonic analysis, theorems that describe decompositions
of functions into sums of spherical harmonics. We extend these classical
theorems (which rely on our understanding of the Laplace operator
$\Delta_{S^2}$) to more general differential operators $\Delta_Q$ that are
constructed with the help of the quadratic form $Q(x, y, z)$. Then we introduce
modular spaces of multipoles. We study their intricate geometry and topology
using methods of algebraic geometry and singularity theory. The multipole
spaces are ramified over vector or projective spaces, and the compliments to
the ramification sets give rise to a rich family of $K(\pi, 1)$-spaces, where
$\pi$ runs over a variety of modified braid groups.


title:
Complete synchronization of convective patterns between Gray-Scott
  systems

abstract:
  Two identical 1D autocatalytic systems with Gray--Scott kinetics--driven
towards convectively unstable regimes and submitted to independent
spatiotemporal Gaussian white noises--are coupled unidirectionally, but
otherwise linearly. Numerical simulation then reveals that (even when perturbed
by noise) the slave system replicates the convective patterns arising in the
master one to a very high degree of precision, as indicated by several measures
of synchronization.


title: Hydrodynamical model atmospheres and 3D spectral synthesis

abstract:
  We discuss three issues in the context of three-dimensional (3D)
hydrodynamical model atmospheres for late-type stars, related to spectral line
shifts, radiative transfer in metal-poor 3D models, and the solar oxygen
abundance. We include a brief overview about the model construction, taking the
radiation-hydrodynamics code CO5BOLD (COnservative COde for the COmputation of
COmpressible COnvection in a BOx of L Dimensions with L=2,3) and the related
spectral synthesis package Linfor3D as examples.


title: Temperature effects on quantum cloning of states and entanglement

abstract:
  Performances of the symmetric universal and phase-covariant cloning
transformations and entanglement cloners -- qubit case -- are investigated when
the initial state of the hardware or the original state to be cloned is weakly
coupled to a thermal environment. Different behaviors of each of these
transformations are analyzed and contrasted with the ideal cases.


title: Large Gauge Hierarchy in Gauge-Higgs Unification

abstract:
  We study a five dimensional nonsupersymmetric SU(3) gauge theory compactified
on $M^4\times S^1/Z_2$. The gauge hierarchy is discussed in the scenario of the
gauge-Higgs unification. We present two models in which the large gauge
hierarchy is realized, that is, the weak scale is naturally is obtained from an
unique large scale such as a GUT and the Planck scale. We also study the Higgs
mass in each model.


title:
Self-organized metal nanostructures through laser driven thermocapillary
  convection

abstract:
  When ultrathin metal films are subjected to multiple cycles of rapid melting
and resolidification by a ns pulsed laser, spatially correlated interfacial
nanostructures can result from a competition among several possible thin film
self-organizing processes. Here we investigate self-organization and the
ensuing length scales when Co films (1-8 nm thick) on SiO_{\text{2}} surfaces
are repeatedly and rapidly melted by non-uniform (interference) laser
irradiation. Pattern evolution produces nanowires, which eventually break-up
into nanoparticles exhibiting spatial order in the nearest neighbor spacing,
\lambda_{NN2}.The scaling behavior is consistent with pattern formation by
thermocapillary flow and a Rayleigh-like instability. For h_{0}\leq2 nm, a
hydrodynamic instability of a spinodally unstable film leads to the formation
of nanoparticles.


title: Full Additivity of the Entanglement of Formation

abstract:
  We present a general strategy that allows a more flexible method for the
construction of fully additive multipartite entanglement monotones than the
ones so far reported in the literature of axiomatic entanglement measures.
Within this framework we give a proof of a conjecture of outstanding
implications in information theory: the full additivity of the Entanglement of
Formation.


title:
Simulation of four-body interaction in a nuclear magnetic resonance
  quantum information processor

abstract:
  Four-body interaction plays an important role in many-body systems, and it
can exhibit interesting phase transition behaviors. Historically it was the
need to efficiently simulate quantum systems that lead the idea of a quantum
computer. In this Letter, we report the experimental demonstration of a
four-body interaction in a four- qubit nuclear magnetic resonance quantum
information processor. The strongly modulating pulse is used to implement spin
selective excitation. The results show a good agreement between theory and
experiment.


title: An Optical Source Catalog of the North Ecliptic Pole Region

abstract:
  We present a five (u*,g',r',i',z') band optical photometry catalog of the
sources in the North Ecliptic Pole (NEP) region based on deep observations made
with MegaCam at CFHT. The source catalog covers about 2 square degree area
centered at the NEP and reaches depths of about 26 mag for u*, g', r' bands,
about 25 mag for i' band, and about 24 mag for z' band (4 sigma detection over
an 1 arcsec aperture). The total number of cataloged sources brighter than r'=
23 mag is about 56,000 including both point sources and extended sources. From
the investigation of photometric properties using the color-magnitude diagrams
and color-color diagrams, we have found that the colors of extended sources are
mostly (u*-r') < 3.0 and (g'-z') > 0.5. This can be used to separate the
extended sources from the point sources reliably, even for the faint source
domain where typical morphological classification schemes hardly work
efficiently. We have derived an empirical color-redshift relation of the red
sequence galaxies using the Sloan Digital Sky Survey data. By applying this
relation to our photometry catalog and searching for any spatial overdensities,
we have found two galaxy clusters and one nearby galaxy group.


title:
Confirmation of Cylindrical Perfect Invisibility Cloak Using
  Fourier-Bessel Analysis

abstract:
  A cylindrical wave expansion method is developed to obtain the scattering
field for an ideal two-dimensional cylindrical invisibility cloak. A near-ideal
model of the invisibility cloak is set up to solve the boundary problem at the
inner boundary of the cloak shell. We confirm that a cloak with the ideal
material parameters is a perfect invisibility cloak by systematically studying
the change of the scattering coefficients from the near-ideal case to the ideal
one. However, due to the slow convergence of the zero$^{th}$ order scattering
coefficients, a tiny perturbation on the cloak would induce a noticeable field
scattering and penetration.


title: Sufficiency Criterion for the Validity of the Adiabatic Approximation

abstract:
  We examine the quantitative condition which has been widely used as a
criterion for the adiabatic approximation but was recently found insufficient.
Our results indicate that the usual quantitative condition is sufficient for a
special class of quantum mechanical systems. For general systems, it may not be
sufficient, but it along with additional conditions is sufficient. The usual
quantitative condition and the additional conditions constitute a general
criterion for the validity of the adiabatic approximation, which is applicable
to all $N-$dimensional quantum systems. Moreover, we illustrate the use of the
general quantitative criterion in some physical models.


title:
Five-dimensional N = 1 AdS superspace: Geometry, off-shell multiplets
  and dynamics

abstract:
  As a step towards formulating projective superspace techniques for
supergravity theories with eight supercharges, this work is devoted to field
theory in five-dimensional N = 1 anti-de Sitter superspace AdS^{5|8} =
SU(2,2|1)/SO(4,1) x U(1) which is a maximally symmetric curved background. We
develop the differential geometry of AdS^{5|8} and describe its isometries in
terms of Killing supervectors. Various off-shell supermultiplets in AdS^{5|8} x
S^2 are defined, and supersymmetric actions are constructed both in harmonic
and projective superspace approaches. Several families of supersymmetric
theories are presented including nonlinear sigma-models, Chern-Simons theories
and vector-tensor dynamical systems. Using a suitable coset representative, we
make use of the coset construction to develop an explicit realization for one
half of the superspace AdS^{5|8} as a trivial fiber bundle with fibers
isomorophic to four-dimensional Minkowski superspace.


title: Domain wall entropy of the bimodal two-dimensional Ising spin glass

abstract:
  We report calculations of the domain wall entropy for the bimodal
two-dimensional Ising spin glass in the critical ground state. The L * L system
sizes are large with L up to 256. We find that it is possible to fit the
variance of the domain wall entropy to a power function of L. However, the
quality of the data distributions are unsatisfactory with large L > 96.
Consequently, it is not possible to reliably determine the fractal dimension of
the domain walls.


title: Magnetic structure of CeRhIn$_{5}$ under magnetic field

abstract:
  The magnetically ordered ground state of CeRhIn$_{5}$ at ambient pressure and
zero magnetic field is an incomensurate helicoidal phase with the propagation
vector $\bf{k}$=(1/2, 1/2, 0.298) and the magnetic moment in the basal plane of
the tetragonal structure. We determined by neutron diffraction the two
different magnetically ordered phases of CeRhIn$_{5}$ evidenced by bulk
measurements under applied magnetic field in its basal plane. The low
temperature high magnetic phase corresponds to a sine-wave structure of the
magnetization being commensurate with $\bf{k}$=(1/2, 1/2, 1/4). At high
temperature, the phase is incommensurate with $\bf{k}$=(1/2, 1/2, 0.298) and a
possible small ellipticity. The propagation vector of this phase is the same as
the one of the zero-field structure.


title: Fermionic Collective Modes in QGP near Critical Temperatures

abstract:
  We investigate the quark spectrum in the quark-gluon plasma phase near color
superconducting (CS) and chiral phase transitions. Owing to the precursory soft
modes of the phase transitions, there appear novel excitaion spectra: In the CS
transition, the quark matter shows non-Fermi liquid behavior and leads to the
pseudogap in the density of states of quarks. In the chiral transition, three
collective excitations appear in the quark spectrum.


title:
The Kinematics and Dynamics of the Globular Clusters and the Planetary
  Nebulae of NGC 5128

abstract:
  A new kinematic and dynamic study of the halo of the giant elliptical galaxy,
NGC 5128, is presented. From a spectroscopically confirmed sample of 340
globular clusters and 780 planetary nebulae, the rotation amplitude, rotation
axis, velocity dispersion, and the total dynamical mass are determined for the
halo of NGC 5128. The globular cluster kinematics were searched for both radial
dependence and metallicity dependence by subdividing the globular cluster
sample into 158 metal-rich ([Fe/H] > -1.0) and 178 metal-poor ([Fe/H] < -1.0)
globular clusters. Our results show the kinematics of the metal-rich and
metal-poor subpopulations are quite similar. The kinematics are compared to the
planetary nebula population where differences are apparent in the outer regions
of the halo. The total mass of NGC 5128 is found using the Tracer Mass
estimator (Evans et al. 2003), to determine the mass supported by internal
random motions, and the spherical component of the Jeans equation to determine
the mass supported by rotation. We find a total mass of (1.0+/-0.2) x 10^(12)
Msun from the planetary nebulae data out to a projected radius of 90 kpc and
(1.3+/-0.5) x 10^(12) Msun from the globular clusters out to a projected radius
of 50 kpc. Lastly, we present a new and homogeneous catalog of known globular
clusters in NGC 5128. This catalog combines all previous definitive cluster
identifications from radial velocity studies and HST imaging studies, as well
as 80 new globular clusters from a study of M.A. Beasley et al. (2007, in
preparation).


title: Topological Properties of Phase Singularities in Wave Fields

abstract:
  Phase singularities as topological objects of wave fields appear in a variety
of physical, chemical, and biological scenarios. In this paper, by making use
of the $\phi$-mapping topological current theory, we study the topological
properties of the phase singularities in two and three dimensional space in
details. The topological inner structure of the phase singularities are
obtained, and the topological charge of the phase singularities are expressed
by the topological numbers: Hopf indices and Brouwer degrees. Furthermore, the
topological invariant of the closed and knotted phase singularities in three
dimensional space are also discussed in details.


title: Five Intermediate-Period Planets from the N2K Sample

abstract:
  We report the detection of five Jovian mass planets orbiting high metallicity
stars. Four of these stars were first observed as part of the N2K program and
exhibited low RMS velocity scatter after three consecutive observations.
However, follow-up observations over the last three years now reveal the
presence of longer period planets with orbital periods ranging from 21 days to
a few years. HD 11506 is a G0V star with a planet of \msini = 4.74 \mjup in a
3.85 year orbit. HD 17156 is a G0V star with a 3.12 \mjup planet in a 21.2 day
orbit. The eccentricity of this orbit is 0.67, one of the highest known for a
planet with a relatively short period. The orbital period for this planet
places it in a region of parameter space where relatively few planets have been
detected. HD 125612 is a G3V star with a planet of \msini = 3.5 \mjup in a 1.4
year orbit. HD 170469 is a G5IV star with a planet of \msini = 0.67 \mjup in a
3.13 year orbit. HD 231701 is an F8V star with planet of 1.08 \mjup in a 142
day orbit. All of these stars have supersolar metallicity. Three of the five
stars were observed photometrically but showed no evidence of brightness
variability. A transit search conducted for HD 17156 was negative but covered
only 25% of the search space and so is not conclusive.


title: Arithmetic homology and an integral version of Katos conjecture

abstract:
  We define an integral Borel-Moore homology theory over finite fields, called
arithmetic homology, and an integral version of Kato homology. Both types of
groups are expected to be finitely generated, and sit in a long exact sequence
with higher Chow groups of zero-cycles.


title:
Production of Anticentauro Events in Ultra-Relativistic Heavy Ion
  Collisions

abstract:
  We propose a novel method for studying the production of anticentauro events
in high energy heavy ion collisions utilizing Chebyshev expansion coefficients.
These coefficients have proved to be very efficient in investigating the
pattern of fluctuations in neutral pion fraction. For the anticentauro like
events, the magnitude of first few coefficients is strongly enhanced (~3 times)
as compared to those of normal HIJING events. Various characteristics of
Chebyshev coefficients are studied in detail and the probability of formation
of exotic events is calculated from the simulated events.


title:
Finite-size scaling of pseudo-critical point distributions in the random
  transverse-field Ising chain

abstract:
  We study the distribution of finite size pseudo-critical points in a
one-dimensional random quantum magnet with a quantum phase transition described
by an infinite randomness fixed point. Pseudo-critical points are defined in
three different ways: the position of the maximum of the average entanglement
entropy, the scaling behavior of the surface magnetization, and the energy of a
soft mode. All three lead to a log-normal distribution of the pseudo-critical
transverse fields, where the width scales as $L^{-1/\nu}$ with $\nu=2$ and the
shift of the average value scales as $L^{-1/\nu_{typ}}$ with $\nu_{typ}=1$,
which we related to the scaling of average and typical quantities in the
critical region.


title: On the Kaehler rank of compact complex surfaces

abstract:
  Harvey and Lawson introduced the Kaehler rank and computed it in connection
to the cone of positive exact currents of bidimension (1,1) for many classes of
compact complex surfaces. In this paper we extend these computations to the
only further known class of surfaces not considered by them, that of Kato
surfaces. Our main tool is the reduction to the dynamics of associated
holomorphic contractions.


title:
Novel algorithm to calculate hypervolume indicator of Pareto
  approximation set

abstract:
  Hypervolume indicator is a commonly accepted quality measure for comparing
Pareto approximation set generated by multi-objective optimizers. The best
known algorithm to calculate it for $n$ points in $d$-dimensional space has a
run time of $O(n^{d/2})$ with special data structures. This paper presents a
recursive, vertex-splitting algorithm for calculating the hypervolume indicator
of a set of $n$ non-comparable points in $d>2$ dimensions. It splits out
multiple child hyper-cuboids which can not be dominated by a splitting
reference point. In special, the splitting reference point is carefully chosen
to minimize the number of points in the child hyper-cuboids. The complexity
analysis shows that the proposed algorithm achieves $O((\frac{d}{2})^n)$ time
and $O(dn^2)$ space complexity in the worst case.


title: Statistical properties of giant pulses from the Crab pulsar

abstract:
  We have studied the statistics of giant pulses from the Crab pulsar for the
first time with particular reference to their widths. We have analyzed data
collected during 3.5 hours of observations conducted with the Westerbork
Synthesis Radio Telescope operated in a tied-array mode at a frequency of 1200
MHz. The PuMa pulsar backend provided voltage recording of X and Y linear
polarization states in two conjugate 10 MHz bands. We restricted the time
resolution to 4 microseconds to match the scattering on the interstellar
inhomogeneities. In total about 18000 giant pulses (GP) were detected in full
intensity with a threshold level of 6 sigma. Cumulative probability
distributions (CPD) of giant pulse energies were analyzed for groups of GPs
with different effective widths in the range 4 to 65 microseconds. The CPDs
were found to manifest notable differences for the different GP width groups.
The slope of a power-law fit to the high-energy portion of the CPDs evolves
from -1.7 to -3.2 when going from the shortest to the longest GPs. There are
breaks in the CPD power-law fits indicating flattening at low energies with
indices varying from -1.0 to -1.9 for the short and long GPs respectively. The
GPs with a stronger peak flux density were found to be of shorter duration. We
compare our results with previously published data and discuss the importance
of these peculiarities in the statistical properties of GPs for the heoretical
understanding of the emission mechanism responsible for GP generation.


title: A Doubly Distributed Genetic Algorithm for Network Coding

abstract:
  We present a genetic algorithm which is distributed in two novel ways: along
genotype and temporal axes. Our algorithm first distributes, for every member
of the population, a subset of the genotype to each network node, rather than a
subset of the population to each. This genotype distribution is shown to offer
a significant gain in running time. Then, for efficient use of the
computational resources in the network, our algorithm divides the candidate
solutions into pipelined sets and thus the distribution is in the temporal
domain, rather that in the spatial domain. This temporal distribution may lead
to temporal inconsistency in selection and replacement, however our experiments
yield better efficiency in terms of the time to convergence without incurring
significant penalties.


title:
Study of resonant processes for multi-pion production in $\bar p
  +p\to\ell ^++\ell^- +n_\pi \pi$ annihilation

abstract:
  In frame of a phenomenological approach based on Compton-like Feynman
amplitudes, we study multi-pion production in antiproton nucleon collisions.
The main interest of this reaction is related to the possibility to study the
properties of the presumable $\bar N N$ atom and of its resonances. For the
case of formation of a scalar or pseudoscalar resonant state, with
$I^G(J^{P})=1^-(0^{\pm}),~0^+(0^-)$ numerical results are obtained. The
differential cross section in an experimental set-up where the pions invariant
mass is measured, is given with explicit dependence on the lepton pair and
pions invariant mass.


title:
Low frequency dispersive estimates for the Schrodinger group in higher
  dimensions

abstract:
  We prove dispersive estimates for the low frequency part of the Schrodinger
group for a large class of potentials in dimensions greater or equal to four.
As a consequence, we extend the result of Journe, Sofer and Sogge to a larger
class of potentials. In this revised version a mistake in the proof of the
estimate (B.4) is removed.


title:
Evaluation of the Axial Vector Commutator Sum Rule for Pion-Pion
  Scattering

abstract:
  We consider the sum rule proposed by one of us (SLA), obtained by taking the
expectation value of an axial vector commutator in a state with one pion. The
sum rule relates the pion decay constant to integrals of pion-pion cross
sections, with one pion off the mass shell. We remark that recent data on
pion-pion scattering allow a precise evaluation of the sum rule. We also
discuss the related Adler--Weisberger sum rule (obtained by taking the
expectation value of the same commutator in a state with one nucleon),
especially in connection with the problem of extrapolation of the pion momentum
off its mass shell. We find, with current data, that both the pion-pion and
pion-nucleon sum rules are satisfied to better than six percent, and we give
detailed estimates of the experimental and extrapolation errors in the closure
discrepancies.


title:
Colour pairs for constraining the age and metallicity of stellar
  populations

abstract:
  Using a widely used stellar population synthesis model, we study the ability
of using pairs of AB system colours to break the well-known stellar
age--metallicity degeneracy and give constraints on the two stellar-population
parameters (age and metallicity). The relative age and metallicity
sensitivities of AB system colours that relate to u, B, g, V, r, R, i, I, z, J,
H, and K bands are presented, and the abilities of various colour pairs for
breaking the age--metallicity degeneracy are quantified by an uncertainty
parameter (UP) method. Our results suggest that a few pairs of colours can be
used to constrain the two above stellar-population parameters. This will be
very useful for exploring the stellar populations of distant galaxies. In
detail, colour pairs [(r-K), (u-R)] and [(r-K), (u-r)] are shown to be the best
pairs for estimating stellar ages and metallicities. They can constrain two
stellar-population parameters on average with age uncertainties less than 3.89
Gyr and metallicity uncertainties less than 0.34 dex for typical uncertainties
in colours. Some other colour pairs, such as [(R-K), (u-R)], [(I-K), (u-R)],
[(R-K), (u-r)] and [(i-J), (u-R)], can possibly be used for constraining the
two parameters, too. As a whole, our results suggest that colours relating to
both UBVRIJHK and ugriz magnitudes are much better than either UBVRIJHK colours
or ugriz colours for breaking the well-known degeneracy. The results also show
that the stellar ages and metallicities of galaxies observed by the Sloan
Digital Sky Survey (SDSS) and the Two-Micron All-Sky Survey (2MASS) can be
estimated via photometry data. It is also shown that the colours can be used in
conjunction with line indices to measure stellar-population parameters.


title: On the Fine Structure of QCD Confining String

abstract:
  This paper had been withdrawn because the prime reported effect had not been
confirmed in further investigations (see arXiv:0812.4488 [hep-lat]).


title:
The effect of supernova asymmetry on coalescence rates of binary neutron
  stars

abstract:
  We study the effect of the kick velocity -- neutron star spin alignment
observed in young radio pulsars on the coalescence rate of binary neutron
stars. The effect is shown to be especially strong for large kick amplitudes
and tight alignments, reducing the galactic rate of binary neutron star
coalescences up to an order of magnitude with respect to the rates calculated
for random kicks. The spin-kick correlation also leads to much narrower NS
spin-orbit misalignments compared to random kicks.


title: Electronic structure of the zigzag spin-chain compound In$_2$VO$_5$

abstract:
  Band structure calculations within the local spin-density approximation are
presented in order to investigate the electronic and magnetic properties of the
zigzag spin-chain compound In$_2$VO$_5$. The essential structural feature of
the system is a double chain of VO$_6$-octahedra, which leads to competing
intrachain and interchain magnetic couplings. Frustration of the spin-chains is
expected for the proposed antiferromagnetic ordering at low temperatures.
However, the band calculations show that the experimental room temperature
crystal structure is incompatible with antiferromagnetism. Both the intrachain
and interchain coupling is found to be ferromagnetic.


title: Elasticity with Arbitrarily Shaped Inhomogeneity

abstract:
  A classical problem in elasticity theory involves an inhomogeneity embedded
in a material of given stress and shear moduli. The inhomogeneity is a region
of arbitrary shape whose stress and shear moduli differ from those of the
surrounding medium. In this paper we present a new, semi-analytic method for
finding the stress tensor for an infinite plate with such an inhomogeneity. The
solution involves two conformal maps, one from the inside and the second from
the outside of the unit circle to the inside, and respectively outside, of the
inhomogeneity. The method provides a solution by matching the conformal maps on
the boundary between the inhomogeneity and the surrounding material. This
matching converges well only for relatively mild distortions of the unit circle
due to reasons which will be discussed in the article. We provide a comparison
of the present result to known previous results.


title: Asymptotic profiles of solutions to viscous Hamilton-Jacobi equations

abstract:
  The large time behavior of solutions to Cauchy problem for viscous
Hamilton-Jacobi equation is classified. The large time asymptotics are given by
very singular self-similar solutions on one hand and by self-similar viscosity
solutions on the other hand


title: Asymptotic profiles of solutions to convection-diffusion equations

abstract:
  The large time behavior of zero mass solutions to the Cauchy problem for a
convection-diffusion equation. We provide conditions on the size and shape of
the initial datum such that the large time asymptotics of solutions is given
either by the derivative of the Guass-Weierstrass kernel or by a self-similar
solution or by a hyperbolic N-wave


title:
Characterization of fragment emission in ^{20}Ne (7 - 10 MeV/nucleon) +
  ^{12}C reactions

abstract:
  The inclusive energy distributions of the complex fragments (3 $\leq$ Z
$\leq$ 7) emitted from the bombardment of ^{12}C by ^{20}Ne beams with incident
energies between 145 and 200 MeV have been measured in the angular range
10$^{o} \leq \theta_{lab} \leq$ 50^{o}. Damped fragment yields in all the cases
have been found to be the characteristic of emission from fully energy
equilibrated composites. The binary fragment yields are compared with the
standard statistical model predictions. Enhanced yields of entrance channel
fragments (5 $\leq$ Z $\leq$ 7) indicate the survival of orbiting-like process
in ^{20}Ne + ^{12}C system at these energies.


title: The dynamics of Jupiter and Saturn in the gaseous proto-planetary disk

abstract:
  We study the possibility that the mutual interactions between Jupiter and
Saturn prevented Type II migration from driving these planets much closer to
the Sun. Our work extends previous results by Masset and Snellgrove (2001), by
exploring a wider set of initial conditions and disk parameters, and by using a
new hydrodynamical code that properly describes for the global viscous
evolution of the disk. Initially both planets migrate towards the Sun, and
Saturn's migration tends to be faster. As a consequence, they eventually end up
locked in a mean motion resonance. If this happens in the 2:3 resonance, the
resonant motion is particularly stable, and the gaps opened by the planets in
the disk may overlap. This causes a drastic change in the torque balance for
the two planets, which substantially slows down the planets' inward migration.
If the gap overlap is substantial, planet migration may even be stopped or
reversed. As the widths of the gaps depend on disk viscosity and scale height,
this mechanism is particularly efficient in low viscosity, cool disks. We
discuss the compatibility of our results with the initial conditions adopted in
Tsiganis et al. (2005) and Gomes et al. (2005) to explain the current orbital
architecture of the giant planets and the origin of the Late Heavy Bombardment
of the Moon.


title: Kinetic Theory for Binary Granular Mixtures at Low-Density

abstract:
  Many features of granular media can be modelled as a fluid of hard spheres
with {\em inelastic} collisions. Under rapid flow conditions, the macroscopic
behavior of grains can be described through hydrodynamic equations. At
low-density, a fundamental basis for the derivation of the hydrodynamic
equations and explicit expressions for the transport coefficients appearing in
them is provided by the Boltzmann kinetic theory conveniently modified to
account for inelastic binary collisions. The goal of this chapter is to give an
overview of the recent advances made for binary granular gases by using kinetic
theory tools. Some of the results presented here cover aspects such as
transport properties, energy nonequipartition, instabilities, segregation or
mixing, non-Newtonian behavior, .... In addition, comparison of the analytical
results with those obtained from Monte Carlo and molecular dynamics simulations
is also carried out, showing the reliability of kinetic theory to describe
granular flows even for strong dissipation.


title: Optical carrier wave shocking: detection and dispersion

abstract:
  Carrier wave shocking is studied using the Pseudo-Spectral Spatial Domain
(PSSD) technique. We describe the shock detection diagnostics necessary for
this numerical study, and verify them against theoretical shocking predictions
for the dispersionless case. These predictions show Carrier Envelope Phase
(CEP) and pulse bandwidth sensitivity in the single-cycle regime. The flexible
dispersion management offered by PSSD enables us to independently control the
linear and nonlinear dispersion. Customized dispersion profiles allow us to
analyze the development of both carrier self-steepening and shocks. The results
exhibit a marked asymmetry between normal and anomalous dispersion, both in the
limits of the shocking regime and in the (near) shocked pulse waveforms.
Combining these insights, we offer some suggestions on how carrier shocking (or
at least extreme self-steepening) might be realised experimentally.


title:
Spin-polarized transport through weakly coupled double quantum dots in
  the Coulomb-blockade regime

abstract:
  We analyze cotunneling transport through two quantum dots in series weakly
coupled to external ferromagnetic leads. In the Coulomb blockade regime the
electric current flows due to third-order tunneling, while the second-order
single-barrier processes have indirect impact on the current by changing the
occupation probabilities of the double dot system. We predict a zero-bias
maximum in the differential conductance, whose magnitude is conditioned by the
value of the inter-dot Coulomb interaction. This maximum is present in both
magnetic configurations of the system and results from asymmetry in cotunneling
through different virtual states. Furthermore, we show that tunnel
magnetoresistance exhibits a distinctively different behavior depending on
temperature, being rather independent of the value of inter-dot correlation.
Moreover, we find negative TMR in some range of the bias voltage.


title: Possible origin of Larson's lows

abstract:
  It was found that approximately constant column densities of giant molecular
clouds (Larson's low) can be explained as cloud existence condition in external
(galactic) gravitational field. This condition can be also applied to objects
(clumps and cores) embedded into the cloud and its gravitational field. Derived
existence condition do not rely on any internal dynamic of a cloud and embedded
objects.


title:
Double Neutron Stars: Evidence For Two Different Neutron-Star Formation
  Mechanisms

abstract:
  Six of the eight double neutron stars known in the Galactic disk have low
orbital eccentricities (< 0.27) indicating that their second-born neutron stars
received only very small velocity kicks at birth. This is similar to the case
of the B-emission X-ray binaries, where a sizable fraction of the neutron stars
received hardly any velocity kick at birth (Pfahl et al. 2002). The masses of
the second-born neutron stars in five of the six low-eccentricity double
neutron stars are remarkably low (between 1.18 and 1.30 Msun). It is argued
that these low-mass, low-kick neutron stars were formed by the electron-capture
collapse of the degenerate O-Ne-Mg cores of helium stars less massive than
about 3.5 Msun, whereas the higher-mass, higher kick-velocity neutron stars
were formed by the collapses of the iron cores of higher initial mass. The
absence of low-velocity single young radio pulsars (Hobbs et al. 2005) is
consistent with the model proposed by Podsiadlowski et al. (2004), in which the
electron-capture collapse of degenerate O-Ne-Mg cores can only occur in binary
systems, and not in single stars.


title: Large Scale Self-Similar Skeletal Structure of the Universe

abstract:
  An analysis of the redshift maps of galaxies and quasars has revealed
large-scale self-similar skeletal structures of the Universe of the same
topology which had been found earlier in a wide range of phenomena, spatial
scales and environments. The "cartwheel" type of structure with diameter ~ 1.5
10^27 cm is discovered in this analysis by means of the method of multi-level
dynamical contrasting. Similar skeletal structures in size up to 1.5 10^28 cm
are found also in the redshift maps of quasars.


title: The Manin conjecture in dimension 2

abstract:
  These lecture notes describe the current state of affairs for Manin's
conjecture in the context of del Pezzo surfaces.


title:
The impact of radio feedback from active galactic nuclei in cosmological
  simulations: Formation of disk galaxies

abstract:
  In this paper, we present a new implementation of feedback due to active
galactic nuclei (AGN) in cosmological simulations of galaxy formation. We
assume that a fraction of jet energy, which is generated by an AGN, is
transferred to the surrounding gas as thermal energy. Combining a theoretical
model of mass accretion onto black holes with a multiphase description of
star-forming gas, we self-consistently follow evolution of both galaxies and
their central black holes. The novelty in our model is that we consider two
distinct accretion modes: standard radiatively efficient thin accretion disks
and radiatively inefficient accretion flows which we will generically refer to
as RIAFs; motivated by theoretical models for jet production in accretion
disks, we assume that only the RIAF is responsible for the AGN feedback. We
find that, after an initial episode of bursting star formation, the accretion
rate onto the central black hole drops so that the accretion disk switches to a
RIAF structure. At this point, the feedback from the AGN becomes efficient and
slightly suppresses star formation in the galactic disk and almost completely
halts star formation in the bulge. As a result, the nucleus becomes a
stochastically fuelled low-luminosity AGN (Seyfert galaxy) with recurrent
short-lived episodes of activity after the star bursts. Our model predicts
several properties of the low-luminosity AGN including the bolometric
luminosity, jet powers, the effect on kpc-scale of the radio jet and the AGN
lifetime, which are in broad agreement with observations of Seyfert galaxies
and their radio activity. We also find that the mass ratios between the central
black hole and the the host spheroid at z = 0 are ~10^{-3} regardless of the
strength of either supernova feedback or AGN feedback. (abridged)


title:
Y-formalism and $b$ ghost in the Non-minimal Pure Spinor Formalism of
  Superstrings

abstract:
  We present the Y-formalism for the non-minimal pure spinor quantization of
superstrings. In the framework of this formalism we compute, at the quantum
level, the explicit form of the compound operators involved in the construction
of the $b$ ghost, their normal-ordering contributions and the relevant
relations among them. We use these results to construct the quantum-mechanical
$b$ ghost in the non-minimal pure spinor formalism. Moreover we show that this
non-minimal $b$ ghost is cohomologically equivalent to the non-covariant $b$
ghost.


title:
A multi-transition molecular line study of candidate massive young
  stellar objects associated with methanol masers

abstract:
  We characterize the molecular environment of candidate massive young stellar
objects (MYSOs) signposted by methanol masers. Single pixel observations of 10
transitions of HCO^+, CO and CS isotopomers were carried out, using the IRAM
30m telescope. We studied a sample of 28 targets for which the 6.7GHz maser
emission positions are known with a sub-arcsecond accuracy. The systemic
velocity inferred from the optically thin lines agrees within 3km/s with the
central velocity of the maser emission for most of the sources. About 64% of
the sources show line wings in one or more transitions of CO, HCO^+ and CS
species, indicating the presence of molecular outflows. Comparison of the
widths of line wings and methanol maser emission suggests that the 6.7GHz maser
line traces the environment of MYSO of various kinematic regimes. Therefore
conditions conducive for the methanol maser can exist in the inner parts of
molecular clouds or circumstellar discs as well as in the outer parts
associated with molecular outflows. Calculations of the physical conditions
based on the CO and HCO^+ lines and the CS line intensity ratios refine the
input parameters for maser models.


title: Dynamics of the Tippe Top via Routhian Reduction

abstract:
  We consider a tippe top modeled as an eccentric sphere, spinning on a
horizontal table and subject to a sliding friction. Ignoring translational
effects, we show that the system is reducible using a Routhian reduction
technique. The reduced system is a two dimensional system of second order
differential equations, that allows an elegant and compact way to retrieve the
classification of tippe tops in six groups as proposed in [1] according to the
existence and stability type of the steady states.


title: Plasmaneutrino spectrum

abstract:
  Spectrum of the neutrinos produced in the massive photon and longitudal
plasmon decay process has been computed with four levels of approximation for
the dispersion relations. Some analytical formulae in limiting cases are
derived. Interesting conclusions related to previous calculations of the energy
loss in stars are presented. High energy tail of the neutrino spectrum is shown
to be proportional to exp(-E/kT), where E is the neutrino energy and kT is the
temperature of the plasma.


title:
Quadratic BSDEs with random terminal time and elliptic PDEs in infinite
  dimension

abstract:
  In this paper we study one dimensional backward stochastic differential
equations (BSDEs) with random terminal time not necessarily bounded or finite
when the generator F(t,Y,Z) has a quadratic growth in Z. We provide existence
and uniqueness of a bounded solution of such BSDEs and, in the case of infinite
horizon, regular dependence on parameters. The obtained results are then
applied to prove existence and uniqueness of a mild solution to elliptic
partial differential equations in Hilbert spaces.


title: Non-minimal Wu-Yang wormhole

abstract:
  We discuss exact solutions of three-parameter non-minimal Einstein-Yang-Mills
model, which describe the wormholes of a new type. These wormholes are
considered to be supported by SU(2)-symmetric Yang-Mills field, non-minimally
coupled to gravity, the Wu-Yang ansatz for the gauge field being used. We
distinguish between regular solutions, describing traversable non-minimal
Wu-Yang wormholes, and black wormholes possessing one or two event horizons.
The relation between the asymptotic mass of the regular traversable Wu-Yang
wormhole and its throat radius is analysed.


title: Patterns of dominant flows in the world trade web

abstract:
  The large-scale organization of the world economies is exhibiting
increasingly levels of local heterogeneity and global interdependency.
Understanding the relation between local and global features calls for
analytical tools able to uncover the global emerging organization of the
international trade network. Here we analyze the world network of bilateral
trade imbalances and characterize its overall flux organization, unraveling
local and global high-flux pathways that define the backbone of the trade
system. We develop a general procedure capable to progressively filter out in a
consistent and quantitative way the dominant trade channels. This procedure is
completely general and can be applied to any weighted network to detect the
underlying structure of transport flows. The trade fluxes properties of the
world trade web determines a ranking of trade partnerships that highlights
global interdependencies, providing information not accessible by simple local
analysis. The present work provides new quantitative tools for a dynamical
approach to the propagation of economic crises.


title:
Hydrogen 2p--2s transition: signals from the epochs of recombination and
  reionization

abstract:
  We propose a method to study the epoch of reionization based on the possible
observation of 2p--2s fine structure lines from the neutral hydrogen outside
the cosmological H {\sc ii} regions enveloping QSOs and other ionizing sources
in the reionization era. We show that for parameters typical of luminous
sources observed at $z \simeq 6.3$ the strength of this signal, which is
proportional to the H {\sc i} fraction, has a brightness temperature $\simeq 20
  \mu K$ for a fully neutral medium. The fine structure line from this redshift
is observable at $\nu \simeq 1 \rm GHz$ and we discuss prospects for the
detection with several operational and future radio telescopes. We also compute
the characteristics of this signal from the epoch of recombination: the peak
brightness is expected to be $\simeq 100 \mu K$; this signal appears in the
frequency range 5-10 MHz. The signal from the recombination era is nearly
impossible to detect owing to the extreme brightness of the Galactic emission
at these frequencies.


title:
Superconductor strip in a closed magnetic environment: exact analytic
  representation of the critical state

abstract:
  An exact analytic representation of the critical state of a current-carrying
type-II superconductor strip located inside a cylindrical magnetic cavity of
high permeability is derived. The obtained results show that, when the cavity
radius is small, penetration of magnetic flux fronts is strongly reduced as
compared to the situation in an isolated strip. From our generic representation
it is possible to establish current profiles in closed cavities of various
other geometries too by means of conformal mapping of the basic configuration
addressed.