title: Enhanced Rare Pion Decays from a Model of MeV Dark Matter

abstract:
  A model has been proposed in which neutral scalar particles chi, of mass 1-10
MeV, annihilate through the exchange of a light vector boson U, of mass 10-100
MeV, to produce the 511 keV line observed emanating from the center of the
galaxy. The chi interacts weakly with normal matter and is a viable dark matter
candidate. If the U-boson couples to quarks as well as to electrons, it could
enhance the branching ratio for the rare decay pi0 -> e+e-. A recent
measurement by the KTeV Collaboration lies three standard deviations above a
prediction by Dorokhov and Ivanov, and we relate this excess to the couplings
of the U-boson. The values are consistent with other constraints and
considerations. We make some comments on possible improvements in the data.


title: Neither black-holes nor regular solitons: a no-go theorem

abstract:
  By studying the BPS equations for electrostatic and spherically symmetric
configurations in N=2, d=5 gauged supergravity with vector multiplets and
hypermultiplets coupled, we demonstrate that no regular supersymmetric
black-hole solutions of this kind exist. Furthermore, we demonstrate that it is
not possible to construct supersymmetric regular solitons that have the above
symmetries. As a consequence the scalar flow associated to the BPS solutions is
always unbounded.


title: The Magnetic Fields of Anomalous X-ray Pulsars

abstract:
  Anomalous X-ray Pulsars (AXPs) belong to a class of neutron stars believed to
harbor the strongest magnetic fields in the universe, as indicated by their
energetic bursts and their rapid spindowns. We have developed a theoretical
model that takes into account processes in the atmospheres and magnetospheres
of ultramagnetic neutron stars, as well as the effects of their strong
gravitational fields on the observable properties. Using this model, we have
analyzed the X-ray spectra of a number of AXPs. We find that in all cases, the
X-ray spectra are described very well with this emission model. The
spectroscopically measured magnetic field strengths of these sources are in
close agreement with the values inferred from their spindown properties and
provide independent evidence for their magnetar nature. The analysis of
spectral data using this physical model also sheds light on the long-term
evolution of AXPs.


title: Probing the chiral limit with clover fermions II: The baryon sector

abstract:
  Algorithmic progress in recent years made it possible to simulate QCD with
Nf=2 flavours of O(a)-improved Wilson fermions at very light quark masses. We
present the current results for baryon spectrum states, the nucleon axial
coupling and the lowest moment of unpolarised nucleon structure functions.
Special emphasis is given to a comparison of our calculations with results from
chiral effective theories.


title: Complexity of hierarchical ensembles

abstract:
  Within the framework of generalized combinatorial approach, complexity is
determined as a disorder measure for hierarchical statistical ensembles related
to Cayley trees possessing arbitrary branching and number of levels. With
strengthening hierarchical coupling, the complexity is shown to increase
monotonically to the limit value that grows with tree branching. In contrast to
the temperature dependence of thermodynamic entropy, the complexity is reduced
by the variance of hierarchical statistical ensemble if the branching exponent
does not exceed the gold mean. Time dependencies are found for both the
probability distribution over ensemble states and the related complexity. The
latter is found explicitly for self-similar ensemble and generalized for
arbitrary hierarchical trees.


title:
The inner radius of T Tauri disks estimated from near-infrared
  interferometry: the importance of scattered light

abstract:
  For young Herbig Ae/Be stars, near-infrared interferometric measurements have
revealed a correlation between the luminosity of the central object and the
position of the disk inner rim. This correlation breaks down for the cooler T
Tauri stars, a fact often interpreted in terms of disks with larger inner
radii. In most cases, the conversion between the observed interferometric
visibility and the calculated disk inner radius was done with a crude disk
emission model. Here, we examine how the use of models that neglect scattered
light can lead to an overestimation of the disk sizes. To do so, synthetic disk
images (and visibilities) are calculated with a full treatment of the radiative
transfer. The relative contributions of thermal emission and scattered light
are compared. We find that the latter can not be neglected for cool stars. For
further comparison, the model visibilities are also converted into inner disk
radii using the same simple disk models as found in the literature. We find
that reliable inner radii can only be estimated for Herbig Ae/Be stars with
these models. However, they lead to a systematic overestimation of the disk
size, by a factor of 2 to 3, for T Tauri stars. We suggest that including
scattered light in the models is a simple (and sufficient) explanation of the
current interferometric measurements of T Tauri stars.


title: Coulomb interactions within Halo Effective Field Theory

abstract:
  I present preliminary results of effective field theory applied to nuclear
cluster systems, where Coulomb interactions play a significant role.


title: Entanglement Mechanisms in One-Dimensional Potential Scattering

abstract:
  When two non-relativistic particles scatter in one dimension, they can become
entangled. This entanglement process is constrained by the symmetries of the
scattering system and the boundary conditions on the incoming state. Applying
these constraints, three different mechanisms of entanglement can be
identified: the superposition of reflected and transmitted modes, momentum
correlations of the reflected mode due to inversion of the relative momentum,
and momentum correlations in the transmitted and reflected modes due to
dependence of the scattering amplitude on the relative momentum. We consider
three standard potentials, the hard core, Dirac delta, and double Dirac delta,
and show that the relative importance of these mechanisms depends on the
interaction and on the properties of the incoming wave function. We find that
even when the momenta distributions of the incoming articles are sharply
peaked, entanglement due to the momentum correlations generated by reflection
can be quite large for particles with unequal mass.


title: Phase transitions of bipartite entanglement

abstract:
  We study a random matrix model for the statistical properties of the purity
of a bipartite quantum system at a finite (fictitious) temperature. This
enables us to write the generating function for the cumulants, for both
balanced and unbalanced bipartitions. It also unveils an unexpected feature of
the system, namely the existence of two phase transitions, characterized by
different spectra of the density matrices. One of the critical phases is
described by the statistical mechanics of random surfaces, the other is a
second-order phase transition.


title: Light Higgses and Dark Matter at Bottom and Charm Factories

abstract:
  Neither Dark Matter nor scalar particles in the Higgs sector are ruled out at
energies accessible to bottom and charm factories. In Dark Matter searches, the
error on the mass of Dark Matter is $\sim 4$ GeV in the best LHC studies. For
light Dark Matter this could represent a 100% (or more) error. In Higgs
searches, the presence of a light singlet Higgs can make the LHC Higgs search
difficult, if not impossible. If Dark Matter or a Higgs scalar is light, it
will {\it require} a low-energy machine to precisely determine the couplings.
We review the models, modes of discovery and rate expectations for these new
particle searches at bottom and charm factories. We also discuss the options
for new runs at bottom and charm factories relevant for these searches.


title: An analytic model for the bispectrum of galaxies in redshift space

abstract:
  We develop an analytic theory for the redshift space bispectrum of dark
matter, haloes and galaxies. This is done within the context of the halo model
of structure formation, as this allows for the self-consistent inclusion of
linear and non-linear redshift space distortions and also for the non-linearity
of the halo bias. The model is applicable over a wide range of scales: on the
largest scales the predictions reduce to those of the standard perturbation
theory (PT); on smaller scales they are determined primarily by the nonlinear
virial velocities of galaxies within haloes, and this gives rise to the
U-shaped anisotropy in the reduced bispectrum -- a finger print of the
Finger-Of-God distortions. We then confront the predictions with bispectrum
measurements from an ensemble of numerical simulations. On very large scales,
k=0.05 h/Mpc, we find reasonably good agreement between our Halo Model, PT and
the data, to within the errors. On smaller scales, k=0.1 h/Mpc, the measured
bispectra differ from the PT at the level of 10-20%, especially for colinear
triangle configurations. The Halo Model predictions improve over PT, but are
accurate to no better than 10%. On smaller scales k=0.5-1.0 h/Mpc, our model
provides a significant improvement over PT, which breaks down. This implies
that studies which use the lowest order PT to extract galaxy bias information
are not robust on scales k>0.1 h/Mpc. The analytic and simulation results also
indicate that there is no observable scale for which the configuration
dependence of the reduced bispectrum is constant--hierarchical models for the
higher order correlation functions in redshift space are unlikely to be useful.
It is hoped that our model will facilitate extraction of information from
large-scale structure surveys of the Universe.


title: On observability of the free core nutation

abstract:
  Neither astronomical technique, including VLBI, can measure nutation
directly. Estimates of parameters of the nutation model are produced by solving
the LSQ problem of adjusting millions parameters using estimates of group
delay. The choice of the mathematical model for nutation used in the estimation
process of analysis of group delays affects our ability to interpret the
results. Ignoring these subtleties and using parameters of the nutation model
either in the form of time series, or in the form of empirical expansion as
"VLBI measurement of nutation", opens a room for misinterpretation and
mistakes. Detailed analysis of the problem reveals that the separation of
forced nutations, atmospheric nutations, ocean nutations, and the retrograde
free core nutation requires invoking some hypotheses, and beyond a specific
level becomes uncertain. This sets a limit of our ability to make an inference
about the free core nutation.


title: General relativistic velocity: the alternative to dark matter

abstract:
  We consider the gravitational collapse of a spherically symmetric ball of
dust in the general relativistic weak gravity regime. The velocity of the
matter as viewed by external observers is compared to the velocity gauged by
local observers. While the comparison in the case of very strong gravity is
seen to follow the pattern familiar from studies of test particles falling
towards a concentrated mass, the case of weak gravity is very different. The
velocity of the dust that is witnessed by external observers is derived for the
critically open case and is seen to differ markedly from the expectations based
upon Newtonian gravity theory. Viewed as an idealized model for a cluster of
galaxies, we find that with the general relativistic velocity expression, the
higher-than-expected constituent velocities observed can be readily correlated
with the solely baryonic measure of the mass, obviating the need to introduce
extraneous dark matter. Hitherto unexplained and subject-to-reinterpretation
astrophysical phenomena could also be considered within this context. It is
suggested that an attempt be made to formulate an experimental design at
smaller scales simulating or realizing a collapse with the aim of implementing
a new test of general relativity.


title: The Structure of a Bernoulli Process Variation of the Fibonacci Sequence

abstract:
  We consider the structure of a variation of the Fibonacci sequence which is
determined by a Bernoulli process. The associated structure of all Bernoulli
variations of the Fibonacci sequence can be represented by a directed binary
tree, which we denote X, with vertex labels representing the specific state of
the recurrence variation. Since X is a binary tree, we can consider the term of
a sequence variation given by a finite traversal of X represented by a binary
code t. We then prove that the traversal of X that is the reflection of the
digits of t gives exactly the integer term corresponding to t. We consider how
to further this result with the statement of an additional conjecture. Finally,
we give connections to Fibonacci expansions, the Stern-Brocot tree, and we
apply our methods to the Three Hat Problem as seen in ``Puzzle Corner'' of the
``Technology Review'' magazine.


title: Lessons about likelihood functions from nuclear physics

abstract:
  Least-squares data analysis is based on the assumption that the normal
(Gaussian) distribution appropriately characterizes the likelihood, that is,
the conditional probability of each measurement d, given a measured quantity y,
p(d | y). On the other hand, there is ample evidence in nuclear physics of
significant disagreements among measurements, which are inconsistent with the
normal distribution, given their stated uncertainties. In this study the
histories of 99 measurements of the lifetimes of five elementary particles are
examined to determine what can be inferred about the distribution of their
values relative to their stated uncertainties. Taken as a whole, the variations
in the data are somewhat larger than their quoted uncertainties would indicate.
These data strongly support using a Student t distribution for the likelihood
function instead of a normal. The most probable value for the order of the t
distribution is 2.6 +/- 0.9. It is shown that analyses based on long-tailed
t-distribution likelihoods gracefully cope with outlying data.


title:
Warm Molecular Gas in M51: Mapping the Excitation Temperature and Mass
  of H_2 with the Spitzer Infrared Spectrograph

abstract:
  We have mapped the warm molecular gas traced by the H_2 S(0) - H_2 S(5) pure
rotational mid-infrared emission lines over a radial strip across the nucleus
and disk of M51 (NGC 5194) using the Infrared Spectrograph (IRS) on the Spitzer
Space Telescope. The six H_2 lines have markedly different emission
distributions. We obtained the H_2 temperature and surface density
distributions by assuming a two temperature model: a warm (T = 100 - 300 K)
phase traced by the low J (S(0) - S(2)) lines and a hot phase (T = 400 - 1000
K) traced by the high J (S(2) - S(5)) lines. The lowest molecular gas
temperatures are found within the spiral arms (T ~ 155 K), while the highest
temperatures are found in the inter-arm regions (T > 700 K). The warm gas
surface density reaches a maximum of 11 M_sun/pc^2 in the northwestern spiral
arm, whereas the hot gas surface density peaks at 0.24 M_sun/pc^2 at the
nucleus. The spatial offset between the peaks in the warm and hot phases and
the differences in the distributions of the H_2 line emission suggest that the
warm phase is mostly produced by UV photons in star forming regions while the
hot phase is mostly produced by shocks or X-rays associated with nuclear
activity. The warm H_2 is found in the dust lanes of M51, spatially offset from
the brightest HII regions. The warm H_2 is generally spatially coincident with
the cold molecular gas traced by CO (J = 1 - 0) emission, consistent with
excitation of the warm phase in dense photodissociation regions (PDRs). In
contrast, the hot H_2 is most prominent in the nuclear region. Here, over a 0.5
kpc radius around the nucleus of M51, the hot H_2 coincides with [O IV](25.89
micron) and X-ray emission indicating that shocks and/or X-rays are responsible
for exciting this phase.


title:
Non-linear force-free field modeling of a solar active region around the
  time of a major flare and coronal mass ejection

abstract:
  Solar flares and coronal mass ejections are associated with rapid changes in
field connectivity and powered by the partial dissipation of electrical
currents in the solar atmosphere. A critical unanswered question is whether the
currents involved are induced by the motion of pre-existing atmospheric
magnetic flux subject to surface plasma flows, or whether these currents are
associated with the emergence of flux from within the solar convective zone. We
address this problem by applying state-of-the-art nonlinear force-free field
(NLFFF) modeling to the highest resolution and quality vector-magnetographic
data observed by the recently launched Hinode satellite on NOAA Active Region
10930 around the time of a powerful X3.4 flare. We compute 14 NLFFF models with
4 different codes and a variety of boundary conditions. We find that the model
fields differ markedly in geometry, energy content, and force-freeness. We
discuss the relative merits of these models in a general critique of present
abilities to model the coronal magnetic field based on surface vector field
measurements. For our application in particular, we find a fair agreement of
the best-fit model field with the observed coronal configuration, and argue (1)
that strong electrical currents emerge together with magnetic flux preceding
the flare, (2) that these currents are carried in an ensemble of thin strands,
(3) that the global pattern of these currents and of field lines are compatible
with a large-scale twisted flux rope topology, and (4) that the ~10^32 erg
change in energy associated with the coronal electrical currents suffices to
power the flare and its associated coronal mass ejection.


title: Super-Massive Neutron Stars

abstract:
  We present here the results of Arecibo timing of PSR B1516+02B, a 7.95-ms
pulsar in a binary system with a ~0.17 solar mass companion and an orbital
period of 6.85 days located in the globular cluster M5. The eccentricity of the
orbit (e = 0.14) has allowed a measurement of the rate of advance of
periastron: (0.0136 +/- 0.0007) degrees per year. It is very likely that the
periastron advance is due to the effects of general relativity; the total mass
of the binary system is (2.14 +/-0.16) solar masses. The small measured mass
function implies, in a statistical sense, that a very large fraction of this
total mass is contained in the pulsar: (1.94+0.17 -0.19) solar masses
(1-sigma); there is a 5% probability that the mass of this object is below 1.59
solar masses. With the possible exception of PSR J1748-2021B, this is the
largest neutron star mass measured to date. When combined with similar
measurements made previously for Terzan 5 I and J, we can exclude, in a
statistical sense, the ``soft'' equations of state for dense neutron matter,
implying that matter at the center of a neutron star is highly incompressible.
There is also some evidence for a bimodal distribution of MSP masses, the
reasons for that are not clear.


title: Equilibrium points for Optimal Investment with Vintage Capital

abstract:
  The paper concerns the study of equilibrium points, namely the stationary
solutions to the closed loop equation, of an infinite dimensional and infinite
horizon boundary control problem for linear partial differential equations.
Sufficient conditions for existence of equilibrium points in the general case
are given and later applied to the economic problem of optimal investment with
vintage capital. Explicit computation of equilibria for the economic problem in
some relevant examples is also provided. Indeed the challenging issue here is
showing that a theoretical machinery, such as optimal control in infinite
dimension, may be effectively used to compute solutions explicitly and easily,
and that the same computation may be straightforwardly repeated in examples
yielding the same abstract structure. No stability result is instead provided:
the work here contained has to be considered as a first step in the direction
of studying the behavior of optimal controls and trajectories in the long run.


title: Deconstructing the High-Mass Star-Forming Region IRAS 23033+5951

abstract:
  We report interferometric observations of the high-mass star-forming object
IRAS 23033+5951. Our observations reveal two massive molecular cloud cores,
designated IRAS 23033+5951-MMS1 and IRAS 23033+5951-MMS2. MMS1 has already
formed a massive protostar and MMS2 appears to be on the verge of doing so. The
latter core may be an example of a massive analogue to a "Class 0" star-forming
object. The more evolved core shows some evidence of N2H+ destruction near the
protostar, consistent with similar findings in low-mass star-forming objects.
In addition to the already-known prominent HCO+ outflow, our SiO 2--1, and
CH3OH 2--1 maps show evidence for two more candidate outflows, both presumably
less powerful than the main one. Both cores are embedded in an elongated
feature whose major axis is oriented almost exactly perpendicular to the axis
of the most prominent outflow in the region. Although it has many of the
characteristics of a disk, the 87,000 AU (0.42 pc) diameter of this structure
suggests that it is more likely to be the flattened, rotating remnant of the
natal molecular cloud fragment from which the star-forming cores condensed. We
conclude that IRAS 23033+5951 is an excellent example of massive star formation
proceeding in relative isolation, perhaps by the method of monolithic collapse
and disk accretion.


title:
A linear equation for Minkowski sums of polytopes relatively in general
  position

abstract:
  The objective of this paper is to study a special family of Minkowski sums,
that is of polytopes relatively in general position. We show that the maximum
number of faces in the sum can be attained by this family. We present a new
linear equation that is satisfied by f-vectors of the sum and the summands. We
study some of the implications of this equation.


title: Pluripolarity of manifolds

abstract:
  By the classical result of E. Bedford, a real-analytic non-generic manifold
is pluripolar. We extend this result for manifolds of the Gevrey class. This
also gives a generalization of the recent result of D. Coman, N. Levenberg and
E. Poletsky on pluripolarity of curves of the Gevrey class.


title:
Entropy growth in the early universe and confirmation of initial big
  bang conditions (Why the quark-gluon model is not the best analogy)

abstract:
  This paper shows how increased entropy values from an initially low big bang
level can be measured experimentally by counting relic gravitons. Furthermore
the physical mechanism of this entropy increase is explained via analogies with
early-universe phase transitions. The rapid increase in entropy so alluded to
without near sudden increases up to 10 to the 88 power may be enough to allow
successful modeling of relic graviton production for entropy in a manner
similar to zero point energy extraction from a vacuum state


title: Glass-forming liquids: One or more "order" parameters?

abstract:
  We first summarize the classical arguments that the vast majority of
glass-forming liquids require more than one "order" parameter for their
description. Critiques against this conventional wisdom are then presented, and
it is argued that the matter deserves to be reconsidered in light of recent
experimental developments. Out of the eight basic thermoviscoelastic
frequency-dependent response functions, there are generally three independent
functions. For stochastic dynamics we show that there are only two independent
response functions; for this case it is shown how analytic continuation may be
utilized to express the third response functions in terms of two others.
Operational criteria are presented for the linear thermoviscoelasticity being
described by a single "order" parameter, in which case there is just one
independent thermoviscoelastic response function. It is shown that a single
"order" parameter description applies to a good approximation whenever thermal
equilibrium fluctuations of fundamental variables like energy and pressure are
strongly correlated. Results from computer simulations showing that this is the
case for a number of simple glass-forming liquids, as well as a few exceptions,
are briefly presented. Finally, we discuss a new conjecture according to which
experiments at varying temperature and pressure follow the density-scaling
expression for the relaxation time, $\tau=F(\rho^x/T)$ ($\rho$ and $T$ are
density and temperature), if and only if the liquid is "strongly correlating,"
i.e., to a good approximation is described by a single "order" parameter.


title: Slider-pinning Rigidity: a Maxwell-Laman-type Theorem

abstract:
  We define and study slider-pinning rigidity, giving a complete combinatorial
characterization. This is done via direction-slider networks, which are a
generalization of Whiteley's direction networks.


title:
Other Meta-Stable Brane Configuration by Adding an Orientifold 6-Plane
  to Giveon-Kutasov

abstract:
  Giveon and Kutasov have found the type IIA intersecting nonsupersymmetric
meta-stable brane configuration where the electric gauge theory superpotential
has a quartic term as well as the mass term for quarks. In this paper, by
adding the orientifold 6-plane to this brane configuration, we describe the
brane configuration corresponding to the meta-stable nonsupersymmetric vacua of
the supersymmetric unitary gauge theory with symmetric flavor as well as
fundamental flavors.


title:
The Environment on few Mpc scales of Infrared Luminous Galaxies at
  Redshifts z~1

abstract:
  We investigate the environment of infrared luminous galaxies (L$_{IR}$[8-1000
$\mu $m$] >10^{11}$L$_{\sun}$). We focus on the redshift range 0.7 $\leq$ z
$\leq$ 1, where these galaxies dominate the star formation activity and play a
significant role in galaxy evolution. We employ MIPS 24$\mu$m data to identify
infrared galaxies in the Extended Groth Strip (EGS). We use a local density
indicator to probe the environment on few Mpc scales and a group member
catalog, both of which make use of the DEEP2 spectroscopic redshift catalog, to
quantify the environment of these galaxies.
  We find that the local environment of LIRGs and ULIRGs is intermediate
between that of blue and red galaxies. LIRGs and ULIRGs avoid underdense
environments and inhabit local environments that are more dense on average than
those of other DEEP2 galaxies at similar redshifts. However, when the
comparison sample of the non-IR DEEP2 galaxies is restricted to have the same
range of stellar mass, color, or luminosity as the IR--galaxies, there is no
longer any significant difference in environment; the IR-galaxies follow the
same trends in the color-environment and luminosity-environment relations
observed at z$\sim$1.
  We also find that about 30% of the LIRGs and ULIRGs belong to groups,
associated with a minimum dark matter halo of
6$\times10^{12}$M$_{\odot}$h$^{-1}$. The group members constitute 20 % of the
sources responsible for the IR star formation rate density and comoving energy
density at z$\sim$1.


title: Dark Energy Constraints from Galaxy Cluster Peculiar Velocities

abstract:
  Future multifrequency microwave background experiments with arcminute
resolution and micro-Kelvin temperature sensitivity will be able to detect the
kinetic Sunyaev-Zeldovich (kSZ) effect, providing a way to measure radial
peculiar velocities of massive galaxy clusters. We show that cluster peculiar
velocities have the potential to constrain several dark energy parameters. We
compare three velocity statistics (the distribution of radial velocities, the
mean pairwise streaming velocity, and the velocity correlation function) and
analyze the relative merits of these statistics in constraining dark energy
parameters. Of the three statistics, mean pairwise streaming velocity provides
constraints that are least sensitive to velocity errors: the constraints on
parameters degrades only by a factor of two when the random error is increased
from 100 to 500 km/s. We also compare cluster velocities with other dark energy
probes proposed in the Dark Energy Task Force report. For cluster velocity
measurements with realistic priors, the eventual constraints on the dark energy
density, the dark energy equation of state and its evolution are comparable to
constraints from supernovae measurements, and better than cluster counts and
baryon acoustic oscillations; adding velocity to other dark energy probes
improves constraints on the figure of merit by more than a factor of two. For
upcoming Sunyaev-Zeldovich galaxy cluster surveys, even velocity measurements
with errors as large as 1000 km/s will substantially improve the cosmological
constraints compared to using the cluster number density alone.


title:
On Myopic Sensing for Multi-Channel Opportunistic Access: Structure,
  Optimality, and Performance

abstract:
  We consider a multi-channel opportunistic communication system where the
states of these channels evolve as independent and statistically identical
Markov chains (the Gilbert-Elliot channel model). A user chooses one channel to
sense and access in each slot and collects a reward determined by the state of
the chosen channel. The problem is to design a sensing policy for channel
selection to maximize the average reward, which can be formulated as a
multi-arm restless bandit process. In this paper, we study the structure,
optimality, and performance of the myopic sensing policy. We show that the
myopic sensing policy has a simple robust structure that reduces channel
selection to a round-robin procedure and obviates the need for knowing the
channel transition probabilities. The optimality of this simple policy is
established for the two-channel case and conjectured for the general case based
on numerical results. The performance of the myopic sensing policy is analyzed,
which, based on the optimality of myopic sensing, characterizes the maximum
throughput of a multi-channel opportunistic communication system and its
scaling behavior with respect to the number of channels. These results apply to
cognitive radio networks, opportunistic transmission in fading environments,
and resource-constrained jamming and anti-jamming.


title: Distributed delays stabilize neural feedback systems

abstract:
  We consider the effect of distributed delays in neural feedback systems. The
avian optic tectum is reciprocally connected with the nucleus isthmi.
Extracellular stimulation combined with intracellular recordings reveal a range
of signal delays from 4 to 9 ms between isthmotectal elements. This observation
together with prior mathematical analysis concerning the influence of a delay
distribution on system dynamics raises the question whether a broad delay
distribution can impact the dynamics of neural feedback loops. For a system of
reciprocally connected model neurons, we found that distributed delays enhance
system stability in the following sense. With increased distribution of delays,
the system converges faster to a fixed point and converges slower toward a
limit cycle. Further, the introduction of distributed delays leads to an
increased range of the average delay value for which the system's equilibrium
point is stable. The enhancement of stability with increasing delay
distribution is caused by the introduction of smaller delays rather than the
distribution per se.


title:
Comparative study of strong coupling theories of a trapped Fermi gas at
  unitarity

abstract:
  We present a systematic comparison of the most recent thermodynamic
measurements of a trapped Fermi gas at unitarity with predictions from strong
coupling theories and quantum Monte Carlo (MC) simulations. The accuracy of the
experimental data, of the order of a few percent, allows a precise test of
different many-body approaches. We find that a Nozieres and Schmitt-Rink
treatment of fluctuations is in excellent agreement with the experimental data
and available MC calculations at unitarity.


title:
Transition form factors of the N*(1535) as a dynamically generated
  resonance

abstract:
  We discuss how electromagnetic properties provide useful tests of the nature
of resonances, and we study these properties for the N*(1535) which appears
dynamically generated from the strong interaction of mesons and baryons. Within
this coupled channel chiral unitary approach, we evaluate the A_1/2 and S_1/2
helicity amplitudes as a function of Q^2 for the electromagnetic N*(1535) to
gamma* N transition. Within the same formalism we evaluate the cross section
for the reactions gamma N to eta N. We find a fair agreement for the absolute
values of the transition amplitudes, as well as for the Q^2 dependence of the
amplitudes, within theoretical and experimental uncertainties discussed in the
paper. The ratios obtained between the S_1/2 and A_1/2 for the neutron or
proton states of the N*(1535) are in qualitative agreement with experiment and
there is agreement on the signs. The same occurs for the ratio of cross
sections for the eta photoproduction on neutron and proton targets in the
vicinity of the N*(1535) energy. The global results support the idea of this
resonance as being dynamically generated, hence, largely built up from meson
baryon components. However, the details of the model indicate that an admixture
with a genuine quark state is also demanded that could help obtain a better
agreement with experimental data.


title: Dynamical coupled-channels: the key to understanding resonances

abstract:
  Recent developments on a dynamical coupled-channels model of hadronic and
electromagnetic production of nucleon resonances are summarized.


title: Quantitative spectroscopy of Deneb

abstract:
  Quantitative spectroscopy of luminous BA-type supergiants offers a high
potential for modern astrophysics. The degree to which we can rely on
quantitative studies of this class of stars as a whole depends on the quality
of the analyses for benchmark objects. We constrain the basic atmospheric
parameters and fundamental stellar parameters as well as chemical abundances of
the prototype A-type supergiant Deneb to unprecedented accuracy (Teff = 8525
+/- 75 K, log(g) = 1.10 +/- 0.05 dex, M_spec = 19 +/- 3 M_sun, L = 1.96 +/-
0.32 *10^5 L_sun, R = 203 +/- 17 R_sun, enrichment with CN-processed matter) by
applying a sophisticated hybrid NLTE spectrum synthesis technique which has
recently been developed and tested. The study is based on a high-resolution and
high-S/N spectrum obtained with the Echelle spectrograph FOCES on the Calar
Alto 2.2m telescope. Practically all inconsistencies reported in earlier
studies are resolved. Multiple metal ionization equilibria and numerous
hydrogen lines from the Balmer, Paschen, Brackett and Pfund series are brought
into match simultaneously for the stellar parameter determination. Stellar wind
properties are derived from H_alpha line-profile fitting using line-blanketed
hydrodynamic non-LTE models. A self-consistent view of Deneb is thus obtained,
allowing us to discuss its evolutionary state in detail by comparison with the
most recent generation of evolution models for massive stars. (abridged)


title: Observational approaches to understanding dark energy

abstract:
  Illuminating the nature of dark energy is one of the most important
challenges in cosmology today. In this review I discuss several promising
observational approaches to understanding dark energy, in the context of the
recommendations by the U.S. Dark Energy Task Force and the ESA-ESO Working
Group on Fundamental Cosmology.


title:
On the Mutual Information Distribution of OFDM-Based Spatial
  Multiplexing: Exact Variance and Outage Approximation

abstract:
  This paper considers the distribution of the mutual information of
frequency-selective spatially-uncorrelated Rayleigh fading MIMO channels.
Results are presented for OFDM-based spatial multiplexing. New exact
closed-form expressions are derived for the variance of the mutual information.
In contrast to previous results, our new expressions apply for systems with
both arbitrary numbers of antennas and arbitrary-length channels. Simplified
expressions are also presented for high and low SNR regimes. The analytical
variance results are used to provide accurate analytical approximations for the
distribution of the mutual information and the outage capacity.


title:
Duality Orbits, Dyon Spectrum and Gauge Theory Limit of Heterotic String
  Theory on T^6

abstract:
  For heterotic string theory compactified on T^6, we derive the complete set
of T-duality invariants which characterize a pair of charge vectors (Q,P)
labelling the electric and magnetic charges of the dyon. Using this we can
identify the complete set of dyons to which the previously derived degeneracy
formula can be extended. By going near special points in the moduli space of
the theory we derive the spectrum of quarter BPS dyons in N=4 supersymmetric
gauge theory with simply laced gauge groups. The results are in agreement with
those derived from field theory analysis.


title: Quantum Statistical Transition

abstract:
  By analyzing the BCS-BEC crossover, I found that because of the pairing
interactions,a continuous family of quantum statistics interpolating between
fermions and bosons is possible, although it seems incapable to construct
reasonable wave function.


title: PT-Symmetry Quantum Electrodynamics--PTQED

abstract:
  The construction of $\mathcal{PT}$-symmetric quantum electrodynamics is
reviewed. In particular, the massless version of the theory in 1+1 dimensions
(the Schwinger model) is solved. Difficulties with unitarity of the $S$-matrix
are discussed.


title:
Taxonomy of asteroid families among the Jupiter Trojans: Comparison
  between spectroscopic data and the Sloan Digital Sky Survey colors

abstract:
  We present a comparative analysis of the spectral slope and color
distributions of Jupiter Trojans, with particular attention to asteroid
families. We use a sample of data from the Moving Object Catalogue of the Sloan
Digital Sky Survey, together with spectra obtained from several surveys. A
first sample of 349 observations, corresponding to 250 Trojan asteroids, were
extracted from the Sloan Digital Sky Survey, and we also extracted from the
literature a second sample of 91 spectra, corresponding to 71 Trojans. The
spectral slopes were computed by means of a least-squares fit to a straight
line of the fluxes obtained from the Sloan observations in the first sample,
and of the rebinned spectra in the second sample. In both cases the reflectance
fluxes/spectra were renormalized to 1 at 6230 $\textrm{\AA}$. We found that the
distribution of spectral slopes among Trojan asteroids shows a bimodality.
About 2/3 of the objects have reddish slopes compatible with D-type asteroids,
while the remaining bodies show less reddish colors compatible with the P-type
and C-type classifications. The members of asteroid families also show a
bimodal distribution with a very slight predominance of D-type asteroids, but
the background is clearly dominated by the D-types. The L4 and L5 swarms show
different distributions of spectral slopes, and bimodality is only observed in
L4. These differences can be attributed to the asteroid families since the
backgraound asteroids show the same slope distribtuions in both swarms. The
analysis of individual families indicates that the families in L5 are
taxonomically homogeneous, but in L4 they show a mixture of taxonomic types. We
discuss a few scenarios that might help to interpret these results.


title:
Effective slip boundary conditions for flows over nanoscale chemical
  heterogeneities

abstract:
  We study slip boundary conditions for simple fluids at surfaces with
nanoscale chemical heterogeneities. Using a perturbative approach, we examine
the flow of a Newtonian fluid far from a surface described by a heterogeneous
Navier slip boundary condition. In the far-field, we obtain expressions for an
effective slip boundary condition in certain limiting cases. These expressions
are compared to numerical solutions which show they work well when applied in
the appropriate limits. The implications for experimental measurements and for
the design of surfaces that exhibit large slip lengths are discussed.


title:
Regge behaviour of distribution functions and evolution of gluon
  distribution function in Next-to-Leading order at low-x

abstract:
  Evolution of gluon distribution function from
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equation in
next-to-leading order (NLO) at low-x is presented assuming the Regge behaviour
of quarks and gluons at this limit. We compare our results of gluon
distribution function with MRST2004, GRV98LO and GRV98NLO parameterizations and
show the compatibility of Regge behaviour of quark and gluon distribution
functions with perturbative quantum chromodynamics (PQCD) at low-x.


title: Fillings method in number theory

abstract:
  Number of results in number theory have been developed using a new method.
The Goldbach binary conjecture in strengthened formulation have been among
them.


title:
The stress-energy tensor of a quark moving through a strongly-coupled
  N=4 supersymmetric Yang-Mills plasma: comparing hydrodynamics and AdS/CFT

abstract:
  The stress-energy tensor of a quark moving through a strongly coupled N=4
supersymmetric Yang-Mills plasma is evaluated using gauge/string duality. The
accuracy with which the resulting wake, in position space, is reproduced by
hydrodynamics is examined. Remarkable agreement is found between hydrodynamics
and the complete result down to distances less than 2/T away from the quark. In
performing the gravitational analysis, we use a relatively simple formulation
of the bulk to boundary problem in which the linearized Einstein field
equations are fully decoupled. Our analysis easily generalizes to other sources
in the bulk.


title:
Effect of heavy-quark energy loss on the muon differential production
  cross section in Pb-Pb collisions at \sqrtsNN=5.5 TeV

abstract:
  We study the nuclear modification factors RAA and RCP of the high transverse
momentum 5<pt<60 GeV/c distribution of muons in Pb--Pb collisions at LHC
energies. We consider two pseudo-rapidity ranges covered by the LHC
experiments: $|\eta|<2.5$ and $2.5<\eta<4$. Muons from semi-leptonic decays of
heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z)
are the main contributions to the muon pt distribution above a few GeV/c. We
compute the heavy quark contributions using available pQCD-based programs. We
include the nuclear shadowing modification of the parton distribution functions
and the in-medium radiative energy loss for heavy quarks, using the
mass-dependent BDMPS quenching weights. Muons from W and Z leptonic decays,
that dominate the yield at high pt, can be used as a medium-blind reference to
observe the medium-induced suppression of beauty quarks.


title:
Phase diagram of nuclear "pasta" and its uncertainties in supernova
  cores

abstract:
  We examine the model dependence of the phase diagram of inhomogeneous nulcear
matter in supernova cores using the quantum molecular dynamics (QMD).
Inhomogeneous matter includes crystallized matter with nonspherical nuclei -
"pasta" phases - and the liquid-gas phase separating nuclear matter. Major
differences between the phase diagrams of the QMD models can be explained by
the energy of pure neutron matter at low densities and the saturation density
of asymmetric nuclear matter. We show the density dependence of the symmetry
energy is also useful to understand uncertainties of the phase diagram. We
point out that, for typical nuclear models, the mass fraction of the pasta
phases in the later stage of the collapsing cores is higher than 10-20 %.


title: Directional recoil rates for WIMP direct detection

abstract:
  New techniques for the laboratory direct detection of dark matter weakly
interacting massive particles (WIMPs) are sensitive to the recoil direction of
the struck nuclei. We compute and compare the directional recoil rates
${dR}/{d\cos\theta}$ (where $\theta$ is the angle measured from a reference
direction in the sky) for several WIMP velocity distributions including the
standard dark halo and anisotropic models such as Sikivie's late-infall halo
model and logarithmic-ellipsoidal models. Since some detectors may be unable to
distinguish the beginning of the recoil track from its end (lack of head-tail
discrimination), we introduce a ``folded'' directional recoil rate
${dR}/{d|\cos\theta|}$, where $|\cos\theta|$ does not distinguish the head from
the tail of the track. We compute the CS$_2$ and CF$_4$ exposures required to
distinguish a signal from an isotropic background noise, and find that
${dR}/{d|\cos\theta|}$ is effective for the standard dark halo and some but not
all anisotropic models.


title: Variational Principles for Water Waves

abstract:
  We describe the Hamiltonian structures, including the Poisson brackets and
Hamiltonians, for free boundary problems for incompressible fluid flows with
vorticity. The Hamiltonian structure is used to obtain variational principles
for stationary gravity waves both for irrotational flows as well as flows with
vorticity.


title: Description of current-driven torques in magnetic tunnel junctions

abstract:
  A free electron description of spin-dependent tranport in magnetic tunnel
junctions with non collinear magnetizations is presented. We investigate the
origin of transverse spin density in tunnelling transport and the quantum
interferences which give rise to oscillatory torques on the local
magnetization. Spin transfer torque is also analyzed and an important bias
asymmetry is found as well as a damped oscillatory behaviour. Furthermore, we
investigate the influence of the s-d exchange coupling on torque in particular
in the case of half-metallic MTJ in which the spin transfer torque is due to
interfacial spin-dependent reflections.


title: Periodic orbits of period 3 in the disc

abstract:
  Let f be an orientation preserving homeomorphism of the disc D2 which
possesses a periodic point of period 3. Then either f is isotopic, relative the
periodic orbit, to a homeomorphism g which is conjugate to a rotation by 2 pi
/3 or 4 pi /3, or f has a periodic point of least period n for each n in N*.


title:
On Precision - Redundancy Relation in the Design of Source Coding
  Algorithms

abstract:
  We study the effects of finite-precision representation of source's
probabilities on the efficiency of classic source coding algorithms, such as
Shannon, Gilbert-Moore, or arithmetic codes. In particular, we establish the
following simple connection between the redundancy $R$ and the number of bits
$W$ necessary for representation of source's probabilities in computer's memory
($R$ is assumed to be small): \begin{equation*} W \lesssim \eta \log_2
\frac{m}{R}, \end{equation*} where $m$ is the cardinality of the source's
alphabet, and $\eta \leqslant 1$ is an implementation-specific constant. In
case of binary alphabets ($m=2$) we show that there exist codes for which $\eta
= 1/2$, and in $m$-ary case ($m > 2$) we show that there exist codes for which
$\eta = m/(m+1)$. In general case, however (which includes designs relying on
progressive updates of frequency counters), we show that $\eta = 1$. Usefulness
of these results for practical designs of source coding algorithms is also
discussed.


title:
Elliptic solutions of the Toda chain and a generalization of the
  Stieltjes-Carlitz polynomials

abstract:
  We construct new elliptic solutions of the restricted Toda chain. These
solutions give rise to a new explicit class of orthogonal polynomials which can
be considered as a generalization of the Stieltjes-Carlitz elliptic
polynomials. Relations between characteristic (i.e. positive definite)
functions, Toda chain and orthogonal polynomials are developed in order to
derive main properties of these polynomials. The recurrence coefficients and
the weight function of these polynomials are expressed explicitly. In the
degenerated cases of the elliptic functions the modified Meixner polynomials
and the Krall-Laguerre polynomials appear.


title: Entanglement-induced Decoherence and Energy Eigenstates

abstract:
  Using recent results in the field of quantum chaos we derive explicit
expressions for the time scale of decoherence induced by the system-environment
entanglement. For a generic system-environment interaction and for a generic
quantum chaotic system as environment, conditions are derived for energy
eigenstates to be preferred states in the weak coupling regime. A simple model
is introduced to numerically confirm our predictions. The results presented
here may also help understanding the dynamics of quantum entanglement
generation in chaotic quantum systems.


title: Dark-State Polaritons for multi-component and stationary light fields

abstract:
  We present a general scheme to determine the loss-free adiabatic
eigensolutions (dark-state polaritons) of the interaction of multiple probe
laser beams with a coherently driven atomic ensemble under conditions of
electromagnetically induced transparency. To this end we generalize the
Morris-Shore transformation to linearized Heisenberg-Langevin equations
describing the coupled light-matter system in the weak excitation limit. For
the simple lambda-type coupling scheme the generalized Morris-Shore
transformation reproduces the dark-state polariton solutions of slow light.
Here we treat a closed-loop dual-V scheme wherein two counter-propagating
control fields generate a quasi stationary pattern of two counter-propagating
probe fields -- so-called stationary light. We show that contrary to previous
predictions,there exists a single unique dark-state polariton; it obeys a
simple propagation equation.


title:
Feshbach shape resonance for high Tc superconductivity in superlattices
  of nanotubes

abstract:
  The case of a Feshbach shape resonance in the pairing mechanism for high T c
superconductivity in a crystalline lattice of doped metallic nanotubes is
described. The superlattice of doped metallic nanotubes provides a
superconductor with a strongly asymmetric gap. The disparity and different
spatial locations of the wave functions of electrons in different subbands at
the Fermi level should suppress the single electron impurity interband
scattering giving multiband superconductivity in the clean limit. The Feshbach
resonances will arise from the component single-particle wave functions out of
which the electron pair wave function is constructed: pairs of wave functions
which are time inverse of each other. The Feshbach shape resonance increases
the critical temperature by tuning the chemical potential at the Lifshitz
electronic topological transition (ETT) where the Fermi surface of one of the
bands changes from the one dimensional (1D) to the two dimensional (2D)
topology (1D/2D ETT).


title:
Multiplicity and angular distribution of particles emitted in
  relativistic nuclear-nuclear interactions

abstract:
  We discuss the experimental results on the behavior of the average
multiplicities and angular distributions of slow particles emitted in
hadron-nuclear and nuclear-nuclear interactions at relativistic energies as a
function of the centrality of collisions. It is observed that by increasing the
mass of the projectiles the angular distributions of slow particles change and
the structure which was demonstrated in the case of pi-mesons, protons and
light nuclear projectiles, almost disappears. During the interaction of the
heavier projectile with nuclear target, the number of secondary interactions as
well as number of nucleon-nucleon elastic scattering and re-scattering events
increases. We suggest to restore this information using the heavy ion
generators taking into account the multiplicity distributions. Because our
investigations show that the formation of the percolation cluster sufficiently
influences the behaviour of the average multiplicity of the slow particles
emitted in these interactions.


title: Suppression of the critical current of a balanced SQUID

abstract:
  We present an experimental study of the magnetic flux dependence of the
critical current of a balanced SQUID with three Josephson junctions in
parallel. Unlike for ordinary dc SQUIDs, the suppression of the critical
current does not depend on the exact parameters of the Josephson junctions. The
suppression is essentially limited only by the inductances of the SQUID loops.
We demonstrate a critical current suppression ratio of higher than 300 in a
balanced SQUID with a maximum critical current 30 nA.


title:
Melting of Single Lipid Components in Binary Lipid Mixtures: A
  Comparison between FTIR Spectroscopy, DSC and Monte Carlo Simulations

abstract:
  Monte Carlo (MC) Simulations, Differential Scanning Calorimetry (DSC) and
Fourier Transform InfraRed (FTIR) spectroscopy were used to study the melting
behavior of single lipid components in two-component membranes of
1,2-Dimyristoyl-D54-sn-Glycero-3-Phosphocholine (DMPC-d54) and
1,2-Distearoyl-sn-Glycero-3-Phosphocholine (DSPC). Microscopic information on
the temperature dependent melting of the single lipid species could be
investigated using FTIR. The microscopic behavior measured could be well
described by the results from the MC simulations. These simulations also
allowed to calculate heat capacity profiles as determined with DSC. These ones
provide macroscopic information about melting enthalpies and entropy changes
which are not accessible with FTIR. Therefore, the MC simulations allowed us to
link the two different experimental approaches of FTIR and DSC.


title:
Linear arrays of non homogeneous Cu sites in the CuO2 plane, a new
  scenario for pairing mechanisms in a currugated-iron-like plane

abstract:
  Experimental results obtained by using x-ray absorption spectroscopy show
that the configurations of Cu sites in the CuO2 plane of Bi 2:2:1:2 high Tc
superconductors are not homogeneous. Different Cu sites are characterized by
short 0.23 nm and long 0.245 nm Cu-O(apical) distances. The linear arrays of
different Cu sites forming domains with a corrugated-iron like shape is
proposed to be a key characteristic of superconducting domains in the CuO2
plane. The wavelength of the modulation is close to the superconducting
coherence length. The ordering of the distorted Cu sites is suggested to be
evidence for ordering of polarons driven by the pseudo Jahn Teller electron
lattice interaction. The Cu L3 XAS experiments on Bi 2:2:1:2 system indicate
that the electronic states added by doping, 4% have the a1 symmetry (i.e. with
Cu 3d(3z2-r2), the combination of O (planar) 2px,y orbital with a1 symmetry
L(a1), and O(apical) 2pz orbital character) and 15% have the b1 symmetry
(3d(x2-y2) and the combination of O (planar) 2p(x,y) orbital with b1 symmetry
L(b1)). This new scenario supports the pairing mechanisms for high Tc
superconductivity in the presence of two components: 1) the more delocalized
component with b1 symmetry and 2) the more localized component, with partially
a1 symmetry associated with different parts of the Fermi surface.


title:
Extension of a Borel subalgebra symmetry into the sl(2) loop algebra
  symmetry for the twisted XXZ spin chain at roots of unity and the Onsager
  algebra

abstract:
  We discuss a conjecture that the twisted transfer matrix of the six-vertex
model at roots of unity with some discrete twist angles should have the sl(2)
loop algebra symmetry. As an evidence of this conjecture, we show the following
mathematical result on a subalgebra of the sl(2) loop algebra, which we call a
Borel subalgebra: any given finite-dimensional highest weight representation of
the Borel subalgebra is extended into that of the sl(2) loop algebra, if the
parameters associated with it are nonzero. Thus, if operators commuting or
anti-commuting with the twisted transfer matrix of the six-vertex model at
roots of unity generate the Borel subalgebra, then they also generate the sl(2)
loop algebra. The result should be useful for studying the connection of the
sl(2) loop algebra symmetry to the Onsager algebra symmetry of the
superintegrable chiral Potts model.


title: Bigravity as an interpretation of the cosmic acceleration

abstract:
  A bimetric description of the universe is proposed, which explains cosmic
acceleration deduced from optically observed high-redshift objects. This
phenomenon is classically charged to a mysterious repulsive "dark energy" whose
true nature is unknown. This is identified in this model with a set of
particles having negative mass and energy. These negative mass particles,
emitting negative energy photons, are not observable using optical instruments.


title: Janet's Algorithm

abstract:
  We have introduced the Janet's algorithm for the Stanley decomposition of a
monomial ideal I in a polynomial ring S = K[x_1,...,x_n] and prove that Janet's
algorithm gives the squarefree Stanley decomposition of S/I for a squarefree
monomial ideal I. We have also shown that the Janet's algorithm gives a
partition of a simplicial complex.


title:
Generalized Bochner theorem: characterization of the Askey-Wilson
  polynomials

abstract:
  Assume that there is a set of monic polynomials $P_n(z)$ satisfying the
second-order difference equation $$ A(s) P_n(z(s+1)) + B(s) P_n(z(s)) + C(s)
P_n(z(s-1)) = \lambda_n P_n(z(s)), n=0,1,2,..., N$$ where $z(s), A(s), B(s),
C(s)$ are some functions of the discrete argument $s$ and $N$ may be either
finite or infinite. The irreducibility condition $A(s-1)C(s) \ne 0$ is assumed
for all admissible values of $s$. In the finite case we assume that there are
$N+1$ distinct grid points $z(s), \: s=0,1,..., N$ such that $z(i) \ne z(j), \:
i \ne j$. If $N=\infty$ we assume that the grid $z(s)$ has infinitely many
different values for different values of $s$. In both finite and infinite cases
we assume also that the problem is non-degenerate, i.e. $\lambda_n \ne
\lambda_m, n \ne m$. Then we show that necessarily: (i) the grid $z(s)$ is at
most quadratic or q-quadratic in $s$; (ii) corresponding polynomials $P_n(z)$
are at most the Askey-Wilson polynomials corresponding to the grid $z(s)$. This
result can be considered as generalizing of the Bochner theorem (characterizing
the ordinary classical polynomials) to generic case of arbitrary difference
operator on arbitrary grids.


title: Isospin Effects on Meson Production in Relativistic Heavy Ion Collisions

abstract:
  We show that the phenomenology of isospin effects on heavy ion reactions at
intermediate energies (few AGeV range) is extremely rich and can allow a
``direct'' study of the covariant structure of the isovector interaction in a
high density hadron medium. We work within a relativistic transport frame,
beyond a cascade picture, consistently derived from effective Lagrangians,
where isospin effects are accounted for in the mean field and collision terms.
We show that rather sensitive observables are provided by the pion/kaon
production (\pi^-/\pi^+, K^0/K^+ yields). Relevant non-equilibrium effects are
stressed. The possibility of the transition to a mixed hadron-quark phase, at
high baryon and isospin density, is finally suggested. Some signatures could
come from an expected ``neutron trapping'' effect.


title:
Continuum Coupling Effects in Spectra of Mirror Nuclei and Binding
  Systematics

abstract:
  Continuum-coupling correction to binding energies in neutron rich oxygen and
fluorine isotopes and to excitation energies of 2+ states in 36Ca and 36S
mirror nuclei are studied using the real-energy continuum shell model.


title:
Coupling times with ambiguities for particle systems and applications to
  context-dependent DNA substitution models

abstract:
  We define a notion of coupling time with ambiguities for interacting particle
systems, and show how this can be used to prove ergodicity and to bound the
convergence time to equilibrium and the decay of correlations at equilibrium. A
motivation is to provide simple conditions which ensure that perturbed particle
systems share some properties of the underlying unperturbed system. We apply
these results to context-dependent substitution models recently introduced by
molecular biologists as descriptions of DNA evolution processes. These models
take into account the influence of the neighboring bases on the substitution
probabilities at a site of the DNA sequence, as opposed to most usual
substitution models which assume that sites evolve independently of each other.


title: Solitons in isotropic antiferromagnets: beyond a sigma model

abstract:
  Isotropic antiferromagnets shows a reach variety of magnetic solitons with
non-trivial static and dynamic properties. One-dimensional soliton elementary
excitations have a periodic dispersion law. For two-dimensional case, planar
antiferromagnetic vortices having non-singular macroscopic core with the
saturated magnetic moment are present. The dynamic properties of these planar
antiferromagnetic vortex are characterized by presence of a gyroforce


title: A note on the phases of natural evolution

abstract:
  The natural evolution of life seems to proceed through steps characterized by
phases of relatively rapid changes, followed by longer, more stable periods. In
the light of the string-theory derived physical scenario proposed in [1], we
discuss how this behaviour can be related to a sequence of resonances of the
energy of natural sources of radiation and absorption energies of the DNA,
responsible for mutagenesis. In a scenario in which these energy scales run
independently as functions of the age of the Universe, the conditions for
evolutionary mutagenesis are satisfied only at discrete points of the time
axis, and for a short period, corresponding to the width of the resonance. We
consider in particular the evolution of the primates through subsequent steps
of increasing cranio-facial contraction, and the great Eras of life (Paleozoic,
Mesozoic, Cenozoic), showing that the transitions occur at the predicted times
of resonance.


title: The non-perturbative equation of state for gluon matter

abstract:
  In order to derive equation of state for the pure SU(3) Yang-Mills fields
from first principles, it is proposed to generalize the effective potential
approach for composite operators to non-zero temperatures. It is essentially
non-perturbative by construction, since it assumes the summation of an infinite
number of the corresponding contributions. There is no dependence on the
coupling constant, only a dependence on the mass gap, which is responsible for
the large-scale structure of the QCD ground state. The equation of state
generalizes the Bag constant at non-zero temperatures, while its nontrivial
Yang-Mills part has been approximated by the generalization of the free gluon
propagator to non-zero temperatures, as a first necessary step. Even in this
case we were able to show explicitly that the pressure may almost continuously
change its regime at $T^* = 266.5 MeV$.All the other thermodynamical quantities
such as energy density, entropy, etc. are to be understood to have drastic
changes in their regimes in the close vicinity of $T^*$. All this is in
qualitative and quantitative agreement with thermal lattice QCD results for the
pure Yang-Mills fields. We have firmly established the behavior of all the
thermodynamical quantities in the region of low temperatures, where thermal
lattice QCD calculations suffer from big uncertainties.


title: Fusion of conformal interfaces

abstract:
  We study the fusion of conformal interfaces in the c=1 conformal field
theory. We uncover an elegant structure reminiscent of that of black holes in
supersymmetric theories. The role of the BPS black holes is played by
topological interfaces, which (a) minimize the entropy function, (b) fix
through an attractor mechanism one or both of the bulk radii, and (c) are
(marginally) stable under splitting. One significant difference is that the
conserved charges are logarithms of natural numbers, rather than vectors in a
charge lattice, as for BPS states. Besides potential applications to
condensed-matter physics and number theory, these results point to the
existence of large solution-generating algebras in string theory.


title: D-brane width

abstract:
  Loop quantum gravity predicts that there are non-zero minimal area, and
non-zero minimal volume in (3+1) dimensions. Given this, one can easily guess
that one will have a non-zero minimal 9-volume in (9+1) dimensions. Therefore,
in this paper, we argue that not only D9-brane but also Dp-brane for p less
than 9 has a 9-volume. This idea is new, as the present view states that such a
Dp-brane has p-volume but no 9 volume. To demonstrate this, first, we equate
D8-brane action with D9-brane action and show that 9th direction which is
perpendicular to D8-brane has non-zero width. We repeat this step for different
ps; we equate Dp-brane action with Dp-1 brane action. By this iteration and
induction we conclude that Dp-brane has non-zero widths for each of (9-p)
directions perpendicular to the Dp-brane, and therefore, non-zero volume. When
antisymmetric tensor and field strength are zero, this width is calculated to
be 2 pi sqrt(alpha') for all (9-p) directions. For non-vanishing antisymmetric
tensor and field strength, the width receives small corrections. In this paper,
we only calculate up to the first order correction.


title: Birational geometry of Fano double covers

abstract:
  We prove divisorial canonicity of Fano double hypersurfaces of general
position.


title:
Non-Oberbeck-Boussinesq effects in turbulent thermal convection in
  ethane close to the critical point

abstract:
  As shown in earlier work (Ahlers et al., J. Fluid Mech. 569, p.409 (2006)),
non-Oberbeck Boussinesq (NOB) corrections to the center temperature in
turbulent Rayleigh-Benard convection in water and also in glycerol are governed
by the temperature dependences of the kinematic viscosity and the thermal
diffusion coefficient. If the working fluid is ethane close to the critical
point the origin of non-Oberbeck-Boussinesq corrections is very different, as
will be shown in the present paper. Namely, the main origin of NOB corrections
then lies in the strong temperature dependence of the isobaric thermal
expansion coefficient \beta(T). More precisely, it is the nonlinear
T-dependence of the density \rho(T) in the buoyancy force which causes another
type of NOB effect. We demonstrate that through a combination of experimental,
numerical, and theoretical work, the latter in the framework of the extended
Prandtl-Blasius boundary layer theory developed in Ahlers et al., J. Fluid
Mech. 569, p.409 (2006). The latter comes to its limits, if the temperature
dependence of the thermal expension coefficient \beta(T) is significant.


title: Universal Landauer conductance in chiral symmetric 2d systems

abstract:
  We study transport properties of an arbitrarily shaped ultraclean graphene
sheet, adiabatically connected to leads,composed by the same material. If the
localized interactions do not destroy chiral symmetry, we show that the
conductance is quantized, since it is dominated by the quasi one-dimensional
leads. As an example, we show that smooth structural deformations of the
graphene plane do not modify the conductance quantization.


title: Radiative Strength Functions for Dipole Transitions in 57, 59Co

abstract:
  Average-resonance data on the (p,gamma) reaction on 56,58Fe that were taken
at proton energies of Ep=1.5-3.0 MeV are used to determine the absolute values
of the radiative strength functions for energies below 10 MeV. The results
obtained in this way are compared with the results of the calculations that
rely on the statistical approach and which take into account the temperature of
the nucleus and its shell structure. Good agreement with experimental data is
achieved without any variation of parameters.


title:
Density perturbations in f(R) gravity theories in metric and Palatini
  formalisms

abstract:
  We make a detailed study of matter density perturbations in both metric and
Palatini formalisms in theories whose Lagrangian density is a general function,
f(R), of the Ricci scalar. We derive these equations in a number of gauges. We
show that for viable models that satisfy cosmological and local gravity
constraints (LGC), matter perturbation equations derived under a sub-horizon
approximation are valid even for super-Hubble scales provided the oscillating
mode (scalaron) does not dominate over the matter-induced mode. Such
approximate equations are especially reliable in the Palatini formalism because
of the absence of scalarons.
  Using these equations we make a comparative study of the behaviour of density
perturbations as well as gravitational potentials for a number of classes of
theories. In the metric formalism the parameter m=Rf_{,RR}/f_{,R}
characterising the deviation from the Lambda CDM model is constrained to be
very small during the matter era in order to ensure compatibility with LGC, but
the models in which m grows to the order of 10^{-1} around the present epoch
can be allowed. These models also suffer from an additional fine tuning due to
the presence of scalaron modes which are absent in the Palatini case.
  In Palatini formalism LGC and background cosmological constraints provide
only weak bounds on |m| by constraining it to be smaller than ~ 0.1. This is in
contrast to matter density perturbations which, on galactic scales, place far
more stringent constraints on the present deviation parameter m of the order of
|m| < 10^{-5} - 10^{-4}. This is due to the peculiar evolution of matter
perturbations in the Palatini case which exhibits a rapid growth or a damped
oscillation depending on the sign of m.


title: Smearing Distributions and their use in Financial Markets

abstract:
  It is shown that superpositions of path integrals with arbitrary Hamiltonians
and different scaling parameters v ("variances") obey the Chapman-Kolmogorov
relation for Markovian processes if and only if the corresponding smearing
distributions for v have a specific functional form. Ensuing "smearing"
distributions substantially simplify the coupled system of Fokker-Planck
equations for smeared and un-smeared conditional probabilities. Simple
application in financial models with stochastic volatility is presented.


title: From vectors to mnesors

abstract:
  The mnesor theory is the adaptation of vectors to artificial intelligence.
The scalar field is replaced by a lattice. Addition becomes idempotent and
multiplication is interpreted as a selection operation. We also show that
mnesors can be the foundation for a linear calculus.


title: On some global problems in the tetrad approach to quasi-local quantities

abstract:
  The potential global topological obstructions to the tetrad approach to
finding the quasi-local conserved quantities, associated with closed,
orientable spacelike 2-surfaces S, are investigated. First we show that the
Lorentz frame bundle is always globally trivializable over an open
neighbourhood U of any such S if an open neighbourhood of S is space and time
orientable, and hence a globally trivializable SL(2,C) spin frame bundle can
also be introduced over U. Then it is shown that all the spin frames belonging
to the same spinor structure on S have always the same homotopy class. On the
other hand, on a 2-surface with genus g, there are $2^{2g}$ homotopically
different Lorentz frame fields, and there is a natural one-to-one
correspondence between these homotopy classes and the different SL(2,C) spinor
structures.


title: Galaxy Formation

abstract:
  I review the current status of theoretical studies of galaxy formation. I
outline the importance of the physics of baryonic component in galaxy formation
by showing results obtained by using two major tools, semi-analytical
approaches and cosmological simulations. In particular, I emphasis on roles of
feedback in galaxy formation and discuss whether apparent conflictions between
the standard theory of structure formation, the cold dark matter model, and
observations can be solved by the feedback. I also discuss future prospects in
numerical simulations of galaxy formation.


title:
Scalar, vectorial and tensorial damage parameters from the mesoscopic
  background

abstract:
  In the mesoscopic theory a distribution of different crack sizes and crack
orientations is introduced. A scalar damage parameter, a second order damage
tensor and a vectorial damage parameter are defined in terms of this
distribution function. As an example of a constitutive quantity the free energy
density is given as a function of the damage tensor. This equation is reduced
in the uniaxial case to a function of the damage vector and in case of a
special geometry to a function of the scalar damage parameter.


title: Elliptic Flow in Central Collisions of Deformed Nuclei

abstract:
  Non-trivial geometrical effects in relativistic central collisions of
deformed nuclei are studied using a simple version of optical Glauber model.
For very small impact parameters large centrality and eccentricity fluctuations
are observed. In very high multiplicity collisions of oblate nuclei (e.g. Au
and Cu) significant fraction of events with elliptic flow strength v_2
dependent on oblateness beta_2 is predicted.


title:
Dynamical Coupled-Channels Model Analysis of \pi-N Scattering and
  Electromagnetic Pion Production Reactions

abstract:
  The ability of the coupled-channels model (MSL) developed in recently in Ref.
\cite{msl} to account simultaneously for the $\pi N$ scattering data and the
$\pi$ photoproduction reactions on the nucleon is presented. An accurate
description of $\pi N$ scattering has been obtained. A preliminary description
of $\pi$ photoproduction is also discussed.


title: The Geometry of Dyonic Instantons in 5-dimensional Supergravity

abstract:
  We systematically construct and study smooth supersymmetric solutions in 5
dimensional N=1 Yang-Mills-Einstein supergravity. Our solution is based on the
ADHM construction of (dyonic) multi-instantons in Yang-Mills theory, which
extends to the gravity-coupled system. In a simple supergravity model obtained
from N=2 theory, our solutions are regular ring-like configurations, which can
also be interpreted as supertubes. By studying the SU(2) 2-instanton example in
detail, we find that angular momentum is maximized, with fixed electric charge,
for circular rings. This feature is qualitatively same as that of supertubes.
Related to the existence of this upper bound of angular momentum, we also check
the absence of closed timelike curves for the circular rings. Finally, in
supergravity and gauge theory models with non-Abelian Chern-Simons terms, we
point out that the solution in the symmetric phase carries electric charge
which does not contribute to the energy. A possible explanation from the
dynamics on the instanton moduli space is briefly discussed.


title: The hyperbolic mean curvature flow

abstract:
  We introduce a geometric evolution equation of hyperbolic type, which governs
the evolution of a hypersurface moving in the direction of its mean curvature
vector. The flow stems from a geometrically natural action containing kinetic
and internal energy terms. As the mean curvature of the hypersurface is the
main driving factor, we refer to this model as the hyperbolic mean curvature
flow (HMCF). The case that the initial velocity field is normal to the
hypersurface is of particular interest: this property is preserved during the
evolution and gives rise to a comparatively simpler evolution equation. We also
consider the case where the manifold can be viewed as a graph over a fixed
manifold. Our main results are as follows. First, we derive several balance
laws satisfied by the hypersurface during the evolution. Second, we establish
that the initial-value problem is locally well-posed in Sobolev spaces; this is
achieved by exhibiting a convexity property satisfied by the energy density
which is naturally associated with the flow. Third, we provide some criteria
ensuring that the flow will blow-up in finite time. Fourth, in the case of
graphs, we introduce a concept of weak solutions suitably restricted by an
entropy inequality, and we prove that a classical solution is unique in the
larger class of entropy solutions. In the special case of one-dimensional
graphs, a global-in-time existence result is established.


title: Antiferromagnetic spherical spin-glass model

abstract:
  We study the thermodynamic properties and the phase diagrams of a multi-spin
antiferromagnetic spherical spin-glass model using the replica method. It is a
two-sublattice version of the ferromagnetic spherical p-spin glass model. We
consider both the replica-symmetric and the one-step replica-symmetry-breaking
solutions, the latter being the most general solution for this model. We find
paramagnetic, spin-glass, antiferromagnetic and mixed or glassy
antiferromagnetic phases. The phase transitions are always of second order in
the thermodynamic sense, but the spin-glass order parameter may undergo a
discontinuous change.


title: Symplectic Jacobi diagrams and the Lie algebra of homology cylinders

abstract:
  Let S be a compact connected oriented surface, whose boundary is connected or
empty. A homology cylinder over the surface S is a cobordism between S and
itself, homologically equivalent to the cylinder over S. The Y-filtration on
the monoid of homology cylinders over S is defined by clasper surgery. Using a
functorial extension of the Le-Murakami-Ohtsuki invariant, we show that the
graded Lie algebra associated to the Y-filtration is isomorphic to the Lie
algebra of ``symplectic Jacobi diagrams.'' This Lie algebra consists of the
primitive elements of a certain Hopf algebra whose multiplication is a
diagrammatic analogue of the Moyal-Weyl product.
  The mapping cylinder construction embeds the Torelli group into the monoid of
homology cylinders, sending the lower central series to the Y-filtration. We
give a combinatorial description of the graded Lie algebra map induced by this
embedding, by connecting Hain's infinitesimal presentation of the Torelli group
to the Lie algebra of symplectic Jacobi diagrams. This Lie algebra map is shown
to be injective in degree two, and the question of the injectivity in higher
degrees is discussed.


title: Zero diffusion-dispersion limits for scalar conservation laws

abstract:
  We consider solutions of hyperbolic conservation laws regularized with
vanishing diffusion and dispersion terms. Following a pioneering work by
Schonbek, we establish the convergence of the regularized solutions toward
discontinuous solutions of the hyperbolic conservation law. The proof relies on
the method of compensated compactness in the $L^2$ setting. Our result improves
upon Schonbek's earlier results and provides an optimal condition on the
balance between the relative sizes of the diffusion and the dispersion
parameters. A convergence result is also established for multi-dimensional
conservation laws by relying on DiPerna's uniqueness theorem for entropy
measure-valued solutions.


title:
Collider Phenomenology of Gauge-Higgs Unification Scenarios in Warped
  Extra Dimensions

abstract:
  We compute the couplings of the zero modes and first excited states of
gluons, $W$'s, $Z$ gauge bosons, as well as the Higgs, to the zero modes and
first excited states of the third generation quarks, in an RS Gauge-Higgs
unification scenario based on a bulk $SO(5)\times U(1)_X$ gauge symmetry, with
gauge and fermion fields propagating in the bulk. Using the parameter space
consistent with electroweak precision tests and radiative electroweak symmetry
breaking, we study numerically the dependence of these couplings on the
parameters of our model. Furthermore, after emphasizing the presence of light
excited states of the top quark, which couple strongly to the Kaluza Klein
gauge bosons, the associated collider phenomenology is analyzed. In particular,
we concentrate on the possible detection of the first excited state of the top,
$t^1$, which tends to have a higher mass than the ones accessible via regular
QCD production processes. We stress that the detection of these particles is
still possible due to an increase in the pair production of $t^1$ induced by
the first excited state of the gluon, $G^1$.


title:
Auxiliary Information and A Priori Values in Construction of Improved
  Estimators

abstract:
  This volume is a collection of six papers on the use of auxiliary information
and 'a priori' values in construction of improved estimators. The work included
here will be of immense application for researchers and students who emply
auxiliary information in any form.


title:
Redundancy Estimates for Word-Based Encoding of Sequences Produced by a
  Bernoulli Source

abstract:
  The efficiency of a code is estimated by its redundancy $R$, while the
complexity of a code is estimated by its average delay $\bar N$. In this work
we construct word-based codes, for which $R \lesssim \bar N^{-5/3}$. Therefore,
word-based codes can attain the same redundancy as block-codes while being much
less complex.
  We also consider uniform on the output codes, the benefit of which is the
lack of a running synchronization error. For such codes $\bar N^{-1} \lesssim R
\lesssim \bar N^{-1}$, except for a case when all input symbols are
equiprobable, when $R \leqslant \bar N^{-2}$ for infinitely many $\bar N$.


title:
Global wellposedness in the energy space for the Maxwell-Schr\"odinger
  system

abstract:
  We prove that the Maxwell-Schr\"odinger system in $\R^{3+1}$ is globally
well-posed in the energy space. The key element of the proof is to obtain a
short time wave packet parametrix for the magnetic Schr\"odinger equation,
which leads to linear, bilinear and trilinear estimates. These, in turn, are
extended to larger time scales via a bootstrap argument.


title:
Optical spin-to-orbital angular momentum conversion in inhomogeneous
  anisotropic media

abstract:
  We demonstrate experimentally an optical process in which the spin angular
momentum carried by a circularly polarized light beam is converted into orbital
angular momentum, leading to the generation of helical modes with a wavefront
helicity controlled by the input polarization. This phenomenon requires the
interaction of light with matter that is both optically inhomogeneous and
anisotropic. The underlying physics is also associated with the so-called
Pancharatnam-Berry geometrical phases involved in any inhomogeneous
transformation of the optical polarization.


title: The UKIDSS Galactic Plane Survey

abstract:
  The UKIDSS Galactic Plane Survey (GPS) is one of the five near infrared
Public Legacy Surveys that are being undertaken by the UKIDSS consortium, using
the Wide Field Camera on the United Kingdom Infrared Telescope. It is surveying
1868 sq.deg. of the northern and equatorial Galactic plane at Galactic
latitudes -5<b<5 in the J, H and K filters and a ~200 sq.deg. area of the
Taurus-Auriga-Perseus molecular cloud complex in these three filters and the
2.12 um (1-0) H_2 filter. It will provide data on ~2 billion sources. Here we
describe the properties of the dataset and provide a user's guide for its
exploitation. We also present brief Demonstration Science results from DR2 and
from the Science Verification programme. These results illustrate how GPS data
will frequently be combined with data taken in other wavebands to produce
scientific results. The Demonstration Science includes studies of: (i) the star
formation region G28.983-0.603, cross matching with Spitzer-GLIMPSE data to
identify YSOs; (ii) the M17 nebula; (iii) H_2 emission in the rho Ophiuchi dark
cloud; (iv) X-ray sources in the Galactic Centre; (v) external galaxies in the
Zone of Avoidance; (vi) IPHAS-GPS optical-infrared spectrophotometric typing.
(abridged).


title:
Pancharatnam-Berry phase optical elements for wavefront shaping in the
  visible domain: switchable helical modes generation

abstract:
  We report the realization of a Pancharatnam-Berry phase optical element [Z.
Bomzon, G. Biener, V. Kleiner, and E. Hasman, Opt. Lett. \textbf{27}, 1141
(2002)] for wavefront shaping working in the visible spectral domain, based on
patterned liquid crystal technology. This device generates helical modes of
visible light with the possibility of electro-optically switching between
opposite helicities by controlling the handedness of the input circular
polarization. By cascading this approach, fast switching among multiple
wavefront helicities can be achieved, with potential applications to
multi-state optical information encoding. The approach demonstrated here can be
generalized to other polarization-controlled devices for wavefront shaping,
such as switchable lenses, beam-splitters, and holographic elements.


title: Univoque numbers and an avatar of Thue-Morse

abstract:
  Univoque numbers are real numbers $\lambda > 1$ such that the number 1 admits
a unique expansion in base $\lambda$, i.e., a unique expansion $1 = \sum_{j
\geq 0} a_j \lambda^{-(j+1)}$, with $a_j \in \{0, 1, ..., \lceil \lambda \rceil
-1\}$ for every $j \geq 0$. A variation of this definition was studied in 2002
by Komornik and Loreti, together with sequences called {\em admissible
sequences}. We show how a 1983 study of the first author gives both a result of
Komornik and Loreti on the smallest admissible sequence on the set $\{0, 1,
>..., b\}$, and a result of de Vries and Komornik (2007) on the smallest
univoque number belonging to the interval $(b, b+1)$, where $b$ is any positive
integer. We also prove that this last number is transcendental. An avatar of
the Thue-Morse sequence, namely the fixed point beginning in 3 of the morphism
$3 \to 31$, $2 \to 30$, $1 \to 03$, $0 \to 02$, occurs in a "universal" manner.


title:
A Construction of Quantum Stabilizer Codes Based on Syndrome Assignment
  by Classical Parity-Check Matrices

abstract:
  In quantum coding theory, stabilizer codes are probably the most important
class of quantum codes. They are regarded as the quantum analogue of the
classical linear codes and the properties of stabilizer codes have been
carefully studied in the literature. In this paper, a new but simple
construction of stabilizer codes is proposed based on syndrome assignment by
classical parity-check matrices. This method reduces the construction of
quantum stabilizer codes to the construction of classical parity-check matrices
that satisfy a specific commutative condition. The quantum stabilizer codes
from this construction have a larger set of correctable error operators than
expected. Its (asymptotic) coding efficiency is comparable to that of CSS
codes. A class of quantum Reed-Muller codes is constructed, which have a larger
set of correctable error operators than that of the quantum Reed-Muller codes
developed previously in the literature. Quantum stabilizer codes inspired by
classical quadratic residue codes are also constructed and some of which are
optimal in terms of their coding parameters.


title:
Symmetric Systems and their Applications to Root Systems Extended by
  Abelian Groups

abstract:
  We investigate the class of root systems R obtained by extending an
irreducible root system by a torsion-free group G. In this context there is a
Weyl group W and a group U with the presentation by conjugation. We show under
additional hypotheses that the kernel of the natural homomorphism from U to W
is isomorphic to the kernel of the homomorphism from the abelianization of U to
that of W. For this we introduce the concept of a symmetric system, a discrete
version of the concept of a symmetric space. Mathematics Subject Classification
2000: 20F55, 17B65, 17B67, 22E65, 22E40. Key Words and Phrases: Weyl group,
root system, presentation by conjugation, extended affine Weyl group (EAWeG),
extended affine root system (EARS), irreducible root system extended by an
abelian group.


title: On estimating the memory for finitarily Markovian processes

abstract:
  Finitarily Markovian processes are those processes
$\{X_n\}_{n=-\infty}^{\infty}$ for which there is a finite $K$ ($K =
K(\{X_n\}_{n=-\infty}^0$) such that the conditional distribution of $X_1$ given
the entire past is equal to the conditional distribution of $X_1$ given only
$\{X_n\}_{n=1-K}^0$. The least such value of $K$ is called the memory length.
We give a rather complete analysis of the problems of universally estimating
the least such value of $K$, both in the backward sense that we have just
described and in the forward sense, where one observes successive values of
$\{X_n\}$ for $n \geq 0$ and asks for the least value $K$ such that the
conditional distribution of $X_{n+1}$ given $\{X_i\}_{i=n-K+1}^n$ is the same
as the conditional distribution of $X_{n+1}$ given $\{X_i\}_{i=-\infty}^n$. We
allow for finite or countably infinite alphabet size.


title: Hessian estimates for the sigma-2 equation in dimension three

abstract:
  We derive a priori interior Hessian estimates for the special Lagrangian
equation $\sigma_{2}=1$ in dimension three.


title: Morse-Novikov cohomology of locally conformally K\"ahler manifolds

abstract:
  A locally conformally Kahler (LCK) manifold is a complex manifold admitting a
Kahler covering, with the monodromy acting on this covering by homotheties. We
define three cohomology invariants, the Lee class, the Morse-Novikov class, and
the Bott-Chern class, of an LCK-structure. These invariants together play the
same role as the Kahler class in Kahler geometry. If these classes for two
LCK-structures coincide, the difference between these structures can be
expressed by a smooth potential, similar to the Kahler case. We show that the
Morse-Novikov class and the Bott-Chern class of a Vaisman manifold vanishes.
Moreover, for any LCK-structure on a Vaisman manifold, we prove that its
Morse-Novikov class vanishes. We show that a compact LCK-manifold $M$ with
vanishing Bott-Chern class admits a holomorphic embedding to a Hopf manifold,
if $\dim_\C M \geq 3$, a result which parallels the Kodaira embedding theorem.


title:
On the moduli of constant mean curvature cylinders of finite type in the
  3-sphere

abstract:
  We show that one-sided Alexandrov embedded constant mean curvature cylinders
of finite type in the 3-sphere are surfaces of revolution. This confirms a
conjecture by Pinkall and Sterling that the only embedded constant mean
curvature tori in the 3-sphere are rotational.


title: Recommended Practices for Spreadsheet Testing

abstract:
  This paper presents the authors recommended practices for spreadsheet
testing. Documented spreadsheet error rates are unacceptable in corporations
today. Although improvements are needed throughout the systems development life
cycle, credible improvement programs must include comprehensive testing.
Several forms of testing are possible, but logic inspection is recommended for
module testing. Logic inspection appears to be feasible for spreadsheet
developers to do, and logic inspection appears to be safe and effective.


title:
Comment on "Group method analysis of magneto-elastico-viscous flow along
  a semi-infinite flat plate with heat transfer", by Helal and Abd-el-Malek

abstract:
  Comment on Group method analysis of magneto-elastico-viscous flow along a
semi-infinite flat plate with heat transfer,Helal and Abd-el-Malek, Journal of
Computational and Applied Mathematics 173 (2005) 199-210.
  In the above paper the authors treat the boundary layer flow of a elasto-
viscous liquid along an infinite plate in the presence of a transverse magnetic
field. The plate temperature is higher than the ambient fluid temperature. The
boundary layer equations are transformed into ordinary ones using the group
theory and subsequently are solved numerically. Velocity, temperature, shear
stress and heat transfer profiles are presented for values of magnetic
parameter M=0, 0.5 and 1. This is an interesting work but there are some
fundamental errors which are presented below.


title: Random sampling of plane partitions

abstract:
  This article presents uniform random generators of plane partitions according
to the size (the number of cubes in the 3D interpretation). Combining a
bijection of Pak with the method of Boltzmann sampling, we obtain random
samplers that are slightly superlinear: the complexity is $O(n (\ln n)^3)$ in
approximate-size sampling and $O(n^{4/3})$ in exact-size sampling
  (under a real-arithmetic computation model). To our knowledge, these are the
first polynomial-time samplers for plane partitions according to the size
(there exist polynomial-time samplers of another type, which draw plane
partitions that fit inside a fixed bounding box). The same principles yield
efficient samplers for $(a\times b)$-boxed plane partitions (plane partitions
with two dimensions bounded), and for skew plane partitions. The random
samplers allow us to perform simulations and observe limit shapes and frozen
boundaries, which have been analysed recently by Cerf and Kenyon for plane
partitions, and by Okounkov and Reshetikhin for skew plane partitions.


title: Atomic Diagnostics of X-ray Irradiated Protoplanetary Disks

abstract:
  We study atomic line diagnostics of the inner regions of protoplanetary disks
with our model of X-ray irradiated disk atmospheres which was previously used
to predict observable levels of the NeII and NeIII fine-structure transitions
at 12.81 and 15.55mum. We extend the X-ray ionization theory to sulfur and
calculate the fraction of sulfur in S, S+, S2+ and sulfur molecules. For the
D'Alessio generic T Tauri star disk, we find that the SI fine-structure line at
25.55mum is below the detection level of the Spitzer Infrared Spectrometer
(IRS), in large part due to X-ray ionization of atomic S at the top of the
atmosphere and to its incorporation into molecules close to the mid-plane. We
predict that observable fluxes of the SII 6718/6732AA forbidden transitions are
produced in the upper atmosphere at somewhat shallower depths and smaller radii
than the neon fine-structure lines. This and other forbidden line transitions,
such as the OI 6300/6363AA and the CI 9826/9852AA lines, serve as complementary
diagnostics of X-ray irradiated disk atmospheres. We have also analyzed the
potential role of the low-excitation fine-structure lines of CI, CII, and OI,
which should be observable by SOFIA and Herschel.


title:
Triaxial orbit based galaxy models with an application to the (apparent)
  decoupled core galaxy NGC 4365

abstract:
  We present a flexible and efficient method to construct triaxial dynamical
models of galaxies with a central black hole, using Schwarzschild's orbital
superposition approach. Our method is general and can deal with realistic
luminosity distributions, which project to surface brightness distributions
that may show position angle twists and ellipticity variations. The models are
fit to measurements of the full line-of-sight velocity distribution (wherever
available). We verify that our method is able to reproduce theoretical
predictions of a three-integral triaxial Abel model. In a companion paper (van
de Ven, de Zeeuw & van den Bosch), we demonstrate that the method recovers the
phase-space distribution function. We apply our method to two-dimensional
observations of the E3 galaxy NGC 4365, obtained with the integral-field
spectrograph SAURON, and study its internal structure, showing that the
observed kinematically decoupled core is not physically distinct from the main
body and the inner region is close to oblate axisymmetric.


title: Similarity of operators and geometry of eigenvector bundles

abstract:
  We characterize the contractions that are similar to the backward shift in
the Hardy space $H^2$. This characterization is given in terms of the geometry
of the eigenvector bundles of the operators.


title:
Vertical stratified turbulent transport mechanism indicated by remote
  sensing

abstract:
  Satellite and shipboard data reveal the intermittent vertical information
transport mechanism of turbulence and internal waves that mixes the ocean,
atmosphere, planets and stars.


title: Generalized Cohn's Theorem

abstract:
  We introduce the notion of a free associative $\mathcal{Z}_2$-algebra on the
union of two disjoint sets and prove a generalization of Cohn's Theorem on
Jordan algebras.


title: Color superconducting quark matter in compact stars

abstract:
  Recent indications for high neutron star masses (M \sim 2 M_sun) and large
radii (R > 12 km) could rule out soft equations of state and have provoked a
debate whether the occurence of quark matter in compact stars can be excluded
as well. We show that modern quantum field theoretical approaches to quark
matter including color superconductivity and a vector meanfield allow a
microscopic description of hybrid stars which fulfill the new, strong
constraints. For these objects color superconductivity turns out to be an
essential ingredient for a successful description of the cooling phenomenology
in accordance with recently developed tests. We discuss the energy release in
the neutrino untrapping transition as a new aspect of the problem that hybrid
stars masquerade themselves as neutron stars. Quark matter searches in future
generations of low-temperature/high-density nucleus-nucleus collision
experiments such as low-energy RHIC and CBM @ FAIR might face the same problem
of an almost crossover behavior of the deconfinement transition. Therefore,
diagnostic tools shall be derived from effects of color superconductivity.


title: Reanalysis of the (0^+,1^+) states B_{s0} and B_{s1} with QCD sum rules

abstract:
  In this article, we calculate the masses and decay constants of the $P$-wave
strange-bottomed mesons $B_{s0}$ and $B_{s1}$ with the QCD sum rules, and
observe that the central values of the masses of the $B_{s0}$ and $B_{s1}$ are
smaller than the corresponding $BK$ and $B^*K$ thresholds respectively, the
strong decays $B_{s0}\to BK$ and $B_{s1}\to B^*K$ are kinematically forbidden.
They can decay through the isospin violation precesses $B_{s0}\to B_s\eta\to
B_s\pi^0$ and $B_{s1}\to B_s^*\eta\to B_s^*\pi^0$. The bottomed mesons $B_{s0}$
and $B_{s1}$, just like their charmed cousins $D_{s0}(2317)$ and
$D_{s1}(2460)$, maybe very narrow.


title: Measurement of Ultrafast Carrier Dynamics in Epitaxial Graphene

abstract:
  Using ultrafast optical pump-probe spectroscopy, we have measured carrier
relaxation times in epitaxial graphene layers grown on SiC wafers. We find two
distinct time scales associated with the relaxation of nonequilibrium
photogenerated carriers. An initial fast relaxation transient in the 70-120 fs
range is followed by a slower relaxation process in the 0.4-1.7 ps range. The
slower relaxation time is found to be inversely proportional to the degree of
crystalline disorder in the graphene layers as measured by Raman spectroscopy.
We relate the measured fast and slow time constants to carrier-carrier and
carrier-phonon intraband and interband scattering processes in graphene.