title: Searching for Multijet Resonances at the LHC

abstract:
  Recently it was shown that there is a class of models in which colored vector
and scalar resonances can be copiously produced at the Tevatron with decays to
multijet final states, consistent with all experimental constraints and having
strong discovery potential. We investigate the collider phenomenology of TeV
scale colored resonances at the LHC and demonstrate a strong discovery
potential for the scalars with early data as well as the vectors with
additional statistics. We argue that the signal can be self-calibrating and
using this fact we propose a search strategy which we show to be robust to
systematic errors typically expected from Monte Carlo background estimates. We
model the resonances with a phenomenological Lagrangian that describes them as
bound states of colored vectorlike fermions due to new confining gauge
interactions. However, the phenomenological Lagrangian treatment is quite
general and can represent other scenarios of microscopic physics as well.


title:
Current Fluctuations and Statistics During a Large Deviation Event in an
  Exactly-Solvable Transport Model

abstract:
  We study the distribution of the time-integrated current in an
exactly-solvable toy model of heat conduction, both analytically and
numerically. The simplicity of the model allows us to derive the full current
large deviation function and the system statistics during a large deviation
event. In this way we unveil a relation between system statistics at the end of
a large deviation event and for intermediate times. Midtime statistics is
independent of the sign of the current, a reflection of the time-reversal
symmetry of microscopic dynamics, while endtime statistics do depend on the
current sign, and also on its microscopic definition. We compare our exact
results with simulations based on the direct evaluation of large deviation
functions, analyzing the finite-size corrections of this simulation method and
deriving detailed bounds for its applicability. We also show how the
Gallavotti-Cohen fluctuation theorem can be used to determine the range of
validity of simulation results.


title:
Exponential Squared Integrability for the Discrepancy Function in Two
  Dimensions

abstract:
  Let A_N be an N-point distribution in the unit square in the Euclidean plane.
We consider the Discrepancy function D_N(x) in two dimensions with respect to
rectangles with lower left corner anchored at the origin and upper right corner
at the point x. This is the difference between the actual number of points of
A_N in such a rectangle and the expected number of points - N x_1x_2 - in the
rectangle. We prove sharp estimates for the BMO norm and the exponential
squared Orlicz norm of D_N(x). For example we show that necessarily
||D_N||_(expL^2) >c(logN)^(1/2) for some aboslute constant c>0. On the other
hand we use a digit scrambled version of the van der Corput set to show that
this bound is tight in the case N=2^n, for some positive integer n. These
results unify the corresponding classical results of Roth and Schmidt in a
sharp fashion.


title: Nanogranular Thermoelectrics

abstract:
  We investigate thermopower and thermoelectric coefficient of nano-granular
materials at large tunneling conductance between the grains, g_{T} >> 1. We
show that at intermediate temperatures, T >= g_{T}\delta, where \delta is the
mean energy level spacing for a single grain, electron-electron interaction
leads to an increase of the thermopower with decreasing grain size. We discuss
our results in the light of new types of thermoelectric materials and present
the behavior of the figure of merit depending on system parameters.


title: The Hall algebra of a spherical object

abstract:
  We determine the Hall algebra, in the sense of Toen, of the algebraic
triangulated category generated by a spherical object.


title: Seesaw Neutrino Mass and New U(1) Gauge Symmetry

abstract:
  The three electroweak doublet neutrinos $\nu_{e,\mu,\tau}$ of the Standard
Model may acquire small seesaw masses, using either three Majorana fermion
singlets $N$ or three Majorana fermion triplets $(\Sigma^+,\Sigma^0,\Sigma^-)$.
It is well-known that the former accommodates the U(1) gauge symmetry $B-L$. It
has also been shown some years ago that the latter supports a new $U(1)_X$
gauge symmetry. Here we study two variations of this $U(1)_X$, one for two $N$
and one $\Sigma$, the other for one $N$ and two $\Sigma$. Phenomenological
consequences are discussed.


abstract:
  Forces on a nanoparticle in an optical trap are analysed. Brownian motion is
found to be one of the major challenges to trap a nanoparticle. Accordingly,
suitable spatial electric field distribution of laser beam is suggested to
enhance the trapping force on a nanoparticle. Theoretical analysis is carried
out to obtain conditions for stable optical trap by incorporating the
temperature variation at large laser intensities. Numerical analysis is made
for single quantum dot of CdS in buffer solution irradiated by an Nd:YAG laser.


title: On the Stochastic Rank of Metric Functions

abstract:
  For a class of integral operators with kernels metric functions on manifold
we find some necessary and sufficient conditions to have finite rank. The
problem we pose has a stochastic nature and boils down to the following
alternative question. For a random sample of discrete points, what will be the
probability the symmetric matrix of pairwise distances to have full rank? When
the metric is an analytic function, the question finds full and satisfactory
answer. As an important application, we consider a class of tensor systems of
equations formulating the problem of recovering a manifold distribution from
its covariance field and solve this problem for representing manifolds such as
Euclidean space and unit sphere.


title: Light-Meson Two-Photon Decays in Full QCD

abstract:
  We present a study of two-photon decays of light mesons, focusing on the
neutral pion decay. This important process highlights the effects of the axial
anomaly in QCD but has been little studied on the lattice. By applying the
Lehmann-Symanzik-Zimmermann (LSZ) reduction formula, we reconstruct the
electromagnetic matrix elements from three-point vector-vector Green functions
calculated on 2+1-flavor isotropic clover lattices.


title: A Theory of Truncated Inverse Sampling

abstract:
  In this paper, we have established a new framework of truncated inverse
sampling for estimating mean values of non-negative random variables such as
binomial, Poisson, hyper-geometrical, and bounded variables. We have derived
explicit formulas and computational methods for designing sampling schemes to
ensure prescribed levels of precision and confidence for point estimators.
Moreover, we have developed interval estimation methods.


title: On a Selberg-Schur integral

abstract:
  A generalization of Selberg's beta integral involving Schur polynomials
associated with partitions with entries not greater than 2 is explicitly
computed. The complex version of this integral is given after proving a general
statement concerning the complex extensions of Selberg-Schur integrals. All
these results have interesting applications in both mathematics and physics,
particularly in conformal field theory, since the conformal blocks for the
$SL(2,\mathbb{R})$ Wess-Zumino-Novikov-Witten model can be obtained by
analytical continuation of these integrals.


title:
Cosmic transparency: A test with the baryon acoustic feature and type Ia
  supernovae

abstract:
  Conservation of the phase-space density of photons plus Lorentz invariance
requires that the cosmological luminosity distance be larger than the angular
diameter distance by a factor of $(1+z)^2$, where $z$ is the redshift. Because
this is a fundamental symmetry, this prediction--known sometimes as the
"Etherington relation" or the "Tolman test"--is independent of world model, or
even the assumptions of homogeneity and isotropy. It depends, however, on
Lorentz invariance and transparency. Transparency can be affected by
intergalactic dust or interactions between photons and the dark sector. Baryon
acoustic feature and type Ia supernovae measures of the expansion history are
differently sensitive to the angular diameter and luminosity distances and can
therefore be used in conjunction to limit cosmic transparency. At the present
day, the comparison only limits the change $\Delta\tau$ in the optical depth
from redshift 0.20 to 0.35 at visible wavelengths to $\Delta\tau < 0.13$ at 95%
confidence. In a model with a constant comoving number density $n$ of
scatterers of constant proper cross-section $\sigma$, this limit implies $n
\sigma< 2\times10^{-4} h \Mpc^{-1}$. These limits depend weakly on the
cosmological world model. Within the next few years, the limits could extend to
redshifts $z\approx2.5$ and improve to $n \sigma<1.1 \times10^{-5} h
\Mpc^{-1}$. Cosmic variance will eventually limit the sensitivity of any test
using the BAF at the $n \sigma\sim 4\times10^{-7} h \Mpc^{-1}$ level.
Comparison with other measures of the transparency is provided; no other
measure in the visible is as free of astrophysical assumptions.


title:
LISA detection of massive black hole binaries: imprint of seed
  populations and of exterme recoils

abstract:
  All the physical processes involved in the formation, merging, and accretion
history of massive black holes along the hierarchical build--up of cosmic
structures are likely to leave an imprint on the gravitational waves detectable
by future space--borne missions, such as LISA. We report here the results of
recent studies, carried out by means of dedicated simulations of black hole
build--up, aiming at understanding the impact on LISA observations of two
ingredients that are crucial in every massive black hole formation scenario,
namely: (i) the nature and abundance of the first black hole seeds and (ii) the
large gravitational recoils following the merger of highly spinning black
holes. We predict LISA detection rates spanning two order of magnitude, in the
range 3-300 events per year, depending on the detail of the assumed massive
black hole seed model. On the other hand, large recoil velocities do not
dramatically compromise the efficiency of LISA observations. The number of
detections may drop substantially (by ~60%), in scenarios characterized
byabundant light seeds, but if seeds are already massive and/or relatively
rare, the detection rate is basically unaffected.


title: TeV variability in blazars: how fast can it be?

abstract:
  Recent Cerenkov observations of the two BL Lac objects PKS 2155-304 and Mkn
501 revealed TeV flux variability by a factor ~2 in just 3-5 minutes. Even
accounting for the effects of relativistic beaming, such short timescales are
challenging simple and conventional emitting models, and call for alternative
ideas. We explore the possibility that extremely fast variable emission might
be produced by particles streaming at ultra-relativistic speeds along magnetic
field lines and inverse Compton scattering any radiation field already present.
This would produce extremely collimated beams of TeV photons. While the
probability for the line of sight to be within such a narrow cone of emission
would be negligibly small, one would expect that the process is not confined to
a single site, but can take place in many very localised regions, along almost
straight magnetic lines. A possible astrophysical setting realising these
conditions is magneto-centrifugal acceleration of beams of particles. In this
scenario, the variability timescale would not be related to the physical
dimension of the emitting volume, but might be determined by either the typical
duration of the process responsible for the production of these high energy
particle beams or by the coherence length of the magnetic field. It is
predicted that even faster TeV variability - with no X-ray counterpart - should
be observed by the foreseen more sensitive Cerenkov telescopes.


title: Fluorescent excitation of Balmer lines in gaseous nebulae: case D

abstract:
  (abridged) Non-ionizing stellar continua are a source of photons for
continuum pumping in the hydrogen Lyman transitions. In the environments where
these transitions are optically thick, deexcitation occurs through higher
series lines, so that the flux in these lines has a fluorescent contribution in
addition to recombination; in particular, Balmer emissivities are
systematically enhanced above case B. The effectiveness of such mechanism in
HII regions and the adequacy of photoionization models as a tool to study it
are the two main focuses of this work. We find that photoionization models of H
II regions illuminated by low-resolution population synthesis models
significantly overpredict the fluorescent contribution to the Balmer lines.
Conversely, photoionization models in which the non-ionizing part of the
continuum is omitted or is not transferred underpredict the fluorescent
contribution to the Balmer lines, producing a bias of similar amplitude in the
opposite direction. In this paper, we carry out realistic estimations of the
fluorescent Balmer intensity and discuss the variations to be expected as the
simulated observational setup and the stellar population's parameters are
varied. In all the cases explored, we find that fluorescent excitation provides
a significant contribution. We also show that differential fluorescent
enhancement may produce line-of-sight differences in the Balmer decrement,
mimicking interstellar extinction. Fluorescent excitation emerges from our
study as a small but important mechanism for the enhancement of Balmer lines,
which should be taken into account in the abundance analysis of photoionized
regions, particularly in the case of high-precision applications such as the
determination of primordial helium.


title: An Effective Theory of Dirac Dark Matter

abstract:
  A stable Dirac fermion with four-fermion interactions to leptons suppressed
by a scale Lambda ~ 1 TeV is shown to provide a viable candidate for dark
matter. The thermal relic abundance matches cosmology, while nuclear recoil
direct detection bounds are automatically avoided in the absence of (large)
couplings to quarks. The annihilation cross section in the early Universe is
the same as the annihilation in our galactic neighborhood. This allows Dirac
fermion dark matter to naturally explain the positron ratio excess observed by
PAMELA with a minimal boost factor, given present astrophysical uncertainties.
We use the Galprop program for propagation of signal and background; we discuss
in detail the uncertainties resulting from the propagation parameters and, more
importantly, the injected spectra. Fermi/GLAST has an opportunity to see a
feature in the gamma-ray spectrum at the mass of the Dirac fermion. The excess
observed by ATIC/PPB-BETS may also be explained with Dirac dark matter that is
heavy. A supersymmetric model with a Dirac bino provides a viable UV model of
the effective theory. The dominance of the leptonic operators, and thus the
observation of an excess in positrons and not in anti-protons, is naturally
explained by the large hypercharge and low mass of sleptons as compared with
squarks. Minimizing the boost factor implies the right-handed selectron is the
lightest slepton, which is characteristic of our model. Selectrons (or
sleptons) with mass less than a few hundred GeV are an inescapable consequence
awaiting discovery at the LHC.


title:
A spectroscopic survey of dwarf galaxies in the Coma Cluster: Stellar
  populations, environment and downsizing

abstract:
  We investigate the stellar populations in a sample of 89 faint (M*+2 to M*+4)
red galaxies in the Coma cluster, using high S/N spectroscopy from the MMT. Our
sample is drawn from two 1-degree fields, one centred on the cluster core and
the other located a degree to the south west of the cluster centre. For a
comparison sample we use published high-S/N data for red-sequence galaxies in
the Shapley Supercluster. We use state-of-the-art stellar population models to
infer the SSP-equivalent age and metallicity (Fe/H) for each galaxy, as well as
the abundances of the light elements Mg, Ca, C and N. The ages of the Coma
dwarfs span a wide range from <2 Gyr to >10 Gyr, with a strong environmental
dependence. The oldest galaxies are found only in the core, while most of the
galaxies in the outer south-west field have ages ~3 Gyr. The galaxies have a
metallicity range -1.0 < [Fe/H] < 0.0, and follow the same age-metallicity-mass
plane as high-mass galaxies, but with increased intrinsic scatter. The Mg/Fe
abundance ratios are on average slightly super-solar, and span a range -0.1 <
[Mg/Fe] < +0.4. The highest Mg enhancements are found only in the cluster core,
while solar ratios predominate in the outskirts. Depending on the assumed
star-formation history (quenched versus burst-dominated), the number of dwarf
galaxies on the red sequence in the Coma core has doubled since z~0.4-0.7.
These estimates bracket the red-sequence growth timescales found by direct
studies of distant clusters. In the south-west field, the red sequence was
established only at z~0.1-0.2. Our observations confirm previous indications of
very recently quenched star formation in this part of the cluster. Our results
support the picture in which much of the cluster passive dwarf population was
generated by environment-driven transformation of infalling late-type galaxies.


title: Topological regluing of rational functions

abstract:
  Regluing is a topological operation that helps to construct topological
models for rational functions on the boundaries of certain hyperbolic
components. It also has a holomorphic interpretation, with the flavor of
infinite dimensional Thurston--Teichm\"uller theory. We will discuss a
topological theory of regluing, and trace a direction in which a holomorphic
theory can develop.


title: Impacts of WIMP dark matter upon stellar evolution: main-sequence stars

abstract:
  The presence of large amounts of WIMP dark matter in stellar cores has been
shown to have significant effects upon models of stellar evolution. We present
a series of detailed grids of WIMP-influenced stellar models for main sequence
stars, computed using the DarkStars code. We describe the changes in stellar
structure and main sequence evolution which occur for masses ranging from 0.3
to 2.0 solar masses and metallicities from Z = 0.0003-0.02, as a function of
the rate of energy injection by WIMPs. We then go on to show what rates of
energy injection can be obtained using realistic orbital parameters for stars
near supermassive black holes, including detailed considerations of dark matter
halo velocity and density profiles. Capture and annihilation rates are strongly
boosted when stars follow elliptical rather than circular orbits, causing WIMP
annihilation to provide up to 100 times the energy of hydrogen fusion in stars
at the Galactic centre.


title:
A High Precision, Optical Polarimeter to Measure Inclinations of High
  Mass X-Ray Binaries

abstract:
  We present commissioning data for the POLISH instrument obtained on the Hale
5-m telescope. The goal of this high precision polarimeter is to constrain
orbital inclination of high mass X-ray binaries and to therefore obtain
independent mass estimates for their black hole companions. We have obtained
photon shot noise limited precision on standard stars, and we have measured the
polarization of bright stars at the part per million level on a nightly basis.
Systematic effects have been reduced to less than 1% of the measured
polarization for polarized sources and to the part per million level for weakly
polarized sources. The high sensitivity of this instrument to asymmetry
suggests that valuable contributions will be made in many other fields,
including studies of extrasolar planets, debris disks, and stellar
astrophysics.


title: Well, Papa, can you multiply triplets?

abstract:
  We show that the classical algebra of quaternions is a commutative
$\Z_2\times\Z_2\times\Z_2$-graded algebra. A similar interpretation of the
algebra of octonions is impossible.


title: Hamiltonians with purely discrete spectrum

abstract:
  We discuss criteria for a self-adjoint operator on L^2(X) to have empty
essential spectrum. We state a general result for the case of a locally compact
abelian group X and give examples for X=R^n.


title: Efficient resolution of the Colebrook equation

abstract:
  A robust, fast and accurate method for solving the Colebrook-like equations
is presented. The algorithm is efficient for the whole range of parameters
involved in the Colebrook equation. The computations are not more demanding
than simplified approximations, but they are much more accurate. The algorithm
is also faster and more robust than the Colebrook solution expressed in term of
the Lambert W-function. Matlab and FORTRAN codes are provided.


title: Limit Behaviour of Sequential Empirical Measure Processes

abstract:
  In this paper, we obtain some uniform laws of large numbers and functional
central limit theorems for sequential empirical measure processes indexed by
classes of product functions satisfying appropriate Vapnik-Chervonenkis
properties.


title: Homology of framed links embedded in thickened surfaces

abstract:
  We construct an infinite family of homology theories of framed links in
thickened surfaces, as well as a homology theory whose graded Euler
characteristic is exactly the Kauffman bracket of the link in the surface. Both
theories are based on ideas coming from Asaeda, Przytycki and Sikora's
categorification of the Kauffman bracket skein module of I-bundles over
surfaces. This is accomplished by borrowing ideas from Bar-Natan's Khovanov
homology theory for tangles and cobordisms and using embedded surfaces to
generate the chain groups, instead of diagrams.


title:
An example of Brunet-Derrida behavior for a branching-selection particle
  system on $\Z$

abstract:
  We consider a branching-selection particle system on $\Z$ with $N \geq 1$
particles. During a branching step, each particle is replaced by two new
particles, whose positions are shifted from that of the original particle by
independently performing two random walk steps according to the distribution $p
\delta_{1} + (1-p) \delta_{0}$, from the location of the original particle.
During the selection step that follows, only the N rightmost particles are kept
among the 2N particles obtained at the branching step, to form a new population
of $N$ particles. After a large number of iterated branching-selection steps,
the displacement of the whole population of $N$ particles is ballistic, with
deterministic asymptotic speed $v_{N}(p)$. As $N$ goes to infinity, $v_{N}(p)$
converges to a finite limit $v_{\infty}(p)$. The main result is that, for every
$0<p<1/2$, as $N$ goes to infinity, the order of magnitude of the difference
$v_{\infty}(p)- v_{N}(p)$ is $\log(N)^{-2}$. This is called Brunet-Derrida
behavior in reference to the 1997 paper by E. Brunet and B. Derrida "Shift in
the velocity of a front due to a cutoff" (see the reference within the paper),
where such a behavior is established for a similar branching-selection particle
system, using both numerical simulations and heuristic arguments.


title:
Effect of Sm-, Gd- codoping on structural modifications in
  aluminoborosilicate glasses under beta-irradiation

abstract:
  Two series of Sm-, Gd-codoped aluminoborosilicate glasses with different
total rare earth content have been studied in order to examine the codoping
effect on the structural modifications of beta-irradiated glasses. The data
obtained by Electron Paramagnetic Resonance spectroscopy indicated that
relative amount of Gd3+ ions located in network former position reveals
non-linear dependence on Sm/Gd ratio. Besides, codoping leads to the evolution
of the EPR signal attributed to defects created by irradiation: superhyperfine
structure of boron oxygen hole centres EPR line becomes less noticeable and
resolved with increase of Gd amount. This fact manifests that Gd3+ ions are
mainly diluted in vicinity of the boron network. By Raman spectroscopy, we
showed that the structural changes induced by the irradiation also reveal
non-linear behaviour with Sm/Gd ratio. In fact, the shift of the Si-O-Si
bending vibration modes has a clear minimum for the samples containing equal
amount of Sm and Gd (50:50) in both series of the investigated glasses. In
contrast, for single doped glass there is no influence of dopant's content on
Si-O-Si shift (in case of Gd) or its diminution (in case of Sm) occurs which is
explained by the reduction process influence. At the same time, no noticeable
effect of codoping on Sm3+ intensity as well as on Sm2+ emission or on Sm
reduction process was observed.


title:
Stability of the vanishing of the $\overline\partial_b$-cohomology under
  small horizontal perturbations of the CR structure in compact abstract
  q-concave CR manifolds

abstract:
  We consider perturbations of CR structures which preserve the complex tangent
bundle. For a compact generic CR manifold its concavity properties and hence
the finiteness of some $\overline\partial_b$-cohomology groups are also
preserved by such perturbations of the CR structure. Here we study the
stability of the vanishing of these groups.


title: Resolution of the Distance Ambiguity for Galactic HII Regions

abstract:
  We resolve the kinematic distance ambiguity for 266 inner Galaxy HII regions
out of a sample of 291 using existing HI and 13CO sky surveys. Our sample
contains all HII regions with measured radio recombination line (RRL) emission
over the extent of the 13CO Boston University-Five College Radio Astronomy
Observatory Galactic Ring Survey (18 deg, < l < 55 deg. and |b| < 1) and
contains ultra compact, compact, and diffuse HII regions. We use two methods
for resolving the distance ambiguity for each HII region: HI
emission/absorption (HIEA) and HI self-absorption (HISA). We find that the HIEA
and HISA methods can resolve the distance ambiguity for 72% and 87% of our
sample, respectively. When projected onto the Galactic plane, this large sample
appears to reveal aspects of Galactic structure, with spiral arm-like features
at Galactocentric radii of 4.5 and 6 kpc, and a lack of HII regions within 3.5
kpc of the Galactic center. Our HII regions are approximately in the ratio of 2
to 1 for far verses near distances. The ratio of far to near distances for
ultra-compact HII regions is 2.2 to 1. Compact HII regions are preferentially
at the near distance; their ratio of far to near distances is 1.6 to 1. Diffuse
HII regions are preferentially at the far distance; their ratio of far to near
distances is 3.8 to 1. This implies that the distinction between ultra compact
and compact HII regions is due largely to distance, and that the large angular
size of diffuse HII regions is not due solely to proximity to the Sun.


title: A note on hyperbolic leaves and wild laminations of rational functions

abstract:
  We study the affine orbifold laminations that were constructed by Lyubich and
Minsky. An important question left open in their construction is whether these
laminations are always locally compact. We show that this is not the case.
  The counterexample we construct has the property that the regular leaf space
contains (many) hyperbolic leaves that intersect the Julia set; whether this
can happen is itself a question raised by Lyubich and Minsky.


title: Enriched spin curves on stable curves with two components

abstract:
  L. Maino constructed a moduli space for enriched stable curves, by blowing-up
the moduli space of Deligne-Mumford stable curves. We introduce enriched spin
curves, showing that a parameter space for these objects is obtained by
blowing-up the moduli space of spin curves.


title:
A branch-and-bound feature selection algorithm for U-shaped cost
  functions

abstract:
  This paper presents the formulation of a combinatorial optimization problem
with the following characteristics: i.the search space is the power set of a
finite set structured as a Boolean lattice; ii.the cost function forms a
U-shaped curve when applied to any lattice chain. This formulation applies for
feature selection in the context of pattern recognition. The known approaches
for this problem are branch-and-bound algorithms and heuristics, that explore
partially the search space. Branch-and-bound algorithms are equivalent to the
full search, while heuristics are not. This paper presents a branch-and-bound
algorithm that differs from the others known by exploring the lattice structure
and the U-shaped chain curves of the search space. The main contribution of
this paper is the architecture of this algorithm that is based on the
representation and exploration of the search space by new lattice properties
proven here. Several experiments, with well known public data, indicate the
superiority of the proposed method to SFFS, which is a popular heuristic that
gives good results in very short computational time. In all experiments, the
proposed method got better or equal results in similar or even smaller
computational time.


title: Neutrino Mass Seesaw Version 3: Recent Developments

abstract:
  The origin of neutrino mass is usually attributed to a seesaw mechanism,
either through a heavy Majorana fermion singlet (version 1) or a heavy scalar
triplet (version 2). Recently, the idea of using a heavy Majorana fermion
triplet (version 3) has gained some attention. This is a review of the basic
idea involved, its U(1) gauge extension, and some recent developments.


title: Detection of parallel steps in programs with arrays

abstract:
  The problem of detecting of information and logically independent (DILD)
steps in programs is a key for equivalent program transformations. Here we are
considering the problem of independence of loop iterations, the concentration
of massive data processing and hence the most challenge construction for
parallelizing. We introduced a separated form of loops when loop's body is a
sequence of procedures each of them are used array's elements selected in a
previous procedure. We prove that any loop may be algorithmically represented
in this form and number of such procedures is invariant. We show that for this
form of loop the steps connections are determined with some integer equations
and hence the independence problem is algorithmically unsolvable if index
expressions are more complex than cubical. We suggest a modification of index
semantics that made connection equations trivial and loops iterations can be
executed in parallel.


title:
Using Subsystem MT2 for Complete Mass Determinations in Decay Chains
  with Missing Energy at Hadron Colliders

abstract:
  We propose to use the MT2 concept to measure the masses of all particles in
SUSY-like events with two unobservable, identical particles. To this end we
generalize the usual notion of MT2 and define a new MT2(n,p,c) variable, which
can be applied to various subsystem topologies, as well as the full event
topology. We derive analytic formulas for its endpoint MT2{max}(n,p,c) as a
function of the unknown test mass Mc of the final particle in the subchain and
the transverse momentum pT due to radiation from the initial state. We show
that the endpoint functions MT2{max}(n,p,c)(Mc,pT) may exhibit three different
types of kinks and discuss the origin of each type. We prove that the subsystem
MT2(n,p,c) variables by themselves already yield a sufficient number of
measurements for a complete determination of the mass spectrum (including the
overall mass scale). As an illustration, we consider the simple case of a decay
chain with up to three heavy particles, X2 -> X1 -> X0, which is rather
problematic for all other mass measurement methods. We propose three different
MT2-based methods, each of which allows a complete determination of the masses
of particles X0, X1 and X2. The first method only uses MT2(n,p,c) endpoint
measurements at a single fixed value of the test mass Mc. In the second method
the unknown mass spectrum is fitted to one or more endpoint functions
MT2{max}(n,p,c)(Mc,pT) exhibiting a kink. The third method is hybrid, combining
MT2 endpoints with measurements of kinematic edges in invariant mass
distributions. As a practical application of our methods, we show that the
dilepton W+W- and tt-bar samples at the Tevatron can be used for an independent
determination of the masses of the top quark, the W boson and the neutrino,
without any prior assumptions.


title: Touchscreen Voting Machines Cause Long Lines and Disenfranchise Voters

abstract:
  Computerized touchscreen "Direct Recording Electronic" DRE voting systems
have been used by over 1/3 of American voters in recent elections. In many
places, insufficient DRE numbers in combination with lengthy ballots and high
voter traffic have caused long lines and disenfranchised voters who left
without voting. We have applied computer queuing simulation to the voting
process and conclude that far more DREs, at great expense, would be needed to
keep waiting times low. Alternatively, paper ballot-optical scan systems can be
easily and economically scaled to prevent long lines and meet unexpected
contingencies.


title: Anonymizing Graphs

abstract:
  Motivated by recently discovered privacy attacks on social networks, we study
the problem of anonymizing the underlying graph of interactions in a social
network. We call a graph (k,l)-anonymous if for every node in the graph there
exist at least k other nodes that share at least l of its neighbors. We
consider two combinatorial problems arising from this notion of anonymity in
graphs. More specifically, given an input graph we ask for the minimum number
of edges to be added so that the graph becomes (k,l)-anonymous. We define two
variants of this minimization problem and study their properties. We show that
for certain values of k and l the problems are polynomial-time solvable, while
for others they become NP-hard. Approximation algorithms for the latter cases
are also given.


title:
Density imbalance effect on the Coulomb drag upturn in an electron-hole
  bialyer

abstract:
  A low-temperature upturn of the Coulomb drag resistivity measured in an
undoped electron-hole bilayer (uEHBL) device, possibly manifesting from exciton
formation or condensation, was recently observed. The effects of density
imbalance on this upturn are examined. Measurements of drag as a function of
temperature in a uEHBL with a 20 nm wide Al$_{.90}$Ga$_{.10}$As barrier layer
at various density imbalances are presented. The results show drag increasing
as the density of either two dimensional system was reduced, both within and
above the upturn temperature regime. A comparison of the data with numerical
calculations of drag in the presence of electron-hole pairing fluctuations,
which qualitatively reproduce the drag upturn behavior, is also presented. The
calculations, however, predict a peak in drag at matched densities, which is
not reflected by the measurements.


title:
Energy dependence of transverse momentum fluctuations in Pb+Pb
  collisions at the CERN Super Proton Synchrotron (SPS) at 20A to 158A GeV

abstract:
  Results are presented on event-by-event fluctuations of transverse momenta
$p_T$ in central Pb+Pb interactions at 20$A$, 30$A$, 40$A$, 80$A$, and 158$A$
GeV. The analysis was performed for charged particles at forward center-of-mass
rapidity ($1.1 < y^{*}_{\pi} < 2.6$). Three fluctuation measures were studied:
the distribution of average transverse momentum - $M(p_T)$ - in the event, the
$\Phi_{p_{T}}$ fluctuation measure and two-particle transverse momentum
correlations. Fluctuations of $p_T$ are small and show no significant energy
dependence in the energy range of the CERN Super Proton Synchrotron. Results
are compared with QCD-inspired predictions for the critical point, and with the
UrQMD model. Transverse momentum fluctuations, similar to multiplicity
fluctuations, do not show the increase expected for freeze-out near the
critical point of QCD.


title: Direct "Delay" Reductions of the Toda Equation

abstract:
  A new direct method of obtaining reductions of the Toda equation is
described. We find a canonical and complete class of all possible reductions
under certain assumptions. The resulting equations are ordinary
differential-difference equations, sometimes referred to as delay-differential
equations. The representative equation of this class is hypothesized to be a
new version of one of the classical Painlev\'e equations. The Lax pair
associated to this equation is obtained, also by reduction.


title: Anonymizing Unstructured Data

abstract:
  In this paper we consider the problem of anonymizing datasets in which each
individual is associated with a set of items that constitute private
information about the individual. Illustrative datasets include market-basket
datasets and search engine query logs. We formalize the notion of k-anonymity
for set-valued data as a variant of the k-anonymity model for traditional
relational datasets. We define an optimization problem that arises from this
definition of anonymity and provide O(klogk) and O(1)-approximation algorithms
for the same. We demonstrate applicability of our algorithms to the America
Online query log dataset.


title: Scenario Planning and Nanotechnological Futures

abstract:
  Scenario planning may assist us in harnessing the benefits of nanotechnology
and managing the associated risks for the good of the society. Scenario
planning is a way to describe the present state of the world and develop
several hypotheses about the future of the world, thereby enabling discussions
about how the world ought to be. Scenario planning thus is not only a tool for
learning and foresight, but also for leadership. Informed decision-making by
experts and political leaders becomes possible, while simultaneously allaying
public's perception of the risks of new and emerging technologies such as
nanotechnology. Two scenarios of the societal impact of nanotechnology are the
mixed-signals scenario and the confluence scenario. Technoscientists have major
roles to play in both scenarios.


title: CM-stability of blow-ups and canonical metrics

abstract:
  An asymptotic formula for the Tian-Paul CM-line of a flat family blown-up at
a flat closed sub-scheme is given. As an application we prove that the blow-up
of a polarized manifold along a (relatively) Chow-unstable submanifold admits
no (extremal) constant scalar curvature Kahler metrics in classes making the
exceptional divisors sufficiently small. Moreover a geometric characterization
of relatively Chow-unstable configuration of points in the projective space is
given. From this we get new examples of classes admitting no extremal Kahler
metric also in the case of the projective plane blown-up at a finite set of
points.


title:
Fabrication of micro-structures for optically driven micromachines using
  two-photon photopolymerization of UV curing resins

abstract:
  Two-photon photopolymerization of UV curing resins is an attractive method
for the fabrication of microscopic transparent objects with size in the tens of
micrometers range. We have been using this method to produce three-dimensional
structures for optical micromanipulation, in an optical system based on a
femtosecond laser. By carefully adjusting the laser power and the exposure time
we were able to create micro-objects with well-defined 3D features and with
resolution below the diffraction limit of light. We discuss the performance and
capabilities of a microfabrication system, with some examples of its products.


title: Magnetoelectric Spin Wave Amplifier for Spin Wave Logic Circuits

abstract:
  We propose and analyze a spin wave amplifier aimed to enhance the amplitude
of the propagating spin wave via the magnetoelectric effect. The amplifier is a
two-layer multiferroic structure, which comprises piezoelectric and
ferromagnetic materials. By applying electric field to the piezoelectric layer,
the stress is produced. In turn, the stress changes the direction of the easy
axis in the ferromagnetic layer and the direction of the anisotropy field. The
rotation frequency of the easy axis is the same as the frequency of the spin
wave propagating through the ferromagnetic layer. As a result of this two-stage
process, the amplitude of the spin wave can be amplified depending on the angle
of the easy axis rotation. We present results of numerical simulations
illustrating the operation of the proposed amplifier. According to numerical
estimates, the amplitude of the spin wave signal can be increased by several
orders of magnitude. The energy efficiency of the electric-to-magnetic power
conversion is discussed. The proposed amplifier preserves the phase of the
initial signal, which is important for application to logic circuits based on
spin waves.


title: More Results on Regular Ultrafilters in ZFC

abstract:
  We prove, in ZFC alone, some new results on regularity and decomposability of
ultrafilters.
  We also list some problems, and furnish applications to topological spaces
and to extended logics.


title:
The magnetic state of 1212-type ruthenocuprate in magnetocaloric and
  magnetoresistivity measurements of polycrystalline samples of
  RuSr2Gd1-xCexCu2O8 and Ru1-xSr2GdCu2O8

abstract:
  The magnetic properties of superconducting Ru1-xSr2GdCu2O8 (x=0, 0.02) and
non-superconducting RuSr2Gd1-xCexCu2O8 (x=0.07, 0.1) were investigated by means
of magnetocaloric experiments with complementary magnetoresistivity and ac
susceptibility measurements. The isothermal magnetocaloric coefficient M_{T}(B)
assumes positive values in a broad range of temperatures (20K<T<231 K) and
magnetic fields (0<B<13 T), i.e. also in the magnetically ordered state
(T_{m}=132 K for RuSr2GdCu2O8 and T_{m}=150 K for RuSr2Gd0.93Ce0.07Cu2O8),
which indicates no gain in the system's magnetic entropy with increasing
magnetic field. The maximum in the M_{T}(B) dependence was observed for
RuSr2GdCu2O8 in a temperature vicinity of T_{m}, which indicates a
ferromagnetic character of the accessed magnetic correlations. No spontaneous
ferromagnetic order was revealed as the M_{T} assumes limiting zero values at
zero magnetic field for the whole range of investigated temperatures.
Temperature dependencies of the specific heat reveal the magnetic-field-induced
positive temperature shift of the anomaly associated with the magnetic
transition in the Ru spin system. The M_{T}(B) dependencies and the
magnetoresistivity data suggest that the magnetic system may be inhomogeneous.


title: A Three-Terminal Spin-Wave Device for Logic Applications

abstract:
  We demonstrate a three-terminal spin wave-based device utilizing spin wave
interference. The device consists of three coplanar transmission lines
inductively coupled to the 100nm thick CoFe film. Two spin wave signals are
excited by microwave fields produced by electric current in two sets of lines,
and the output signal is detected by the third set. The initial phases of the
spin wave signals are controlled by the direction of the current flow in the
excitation set of lines. Experimental data show prominent output signal
modulation as a function of the relative phase (in-phase and out-of phase) of
two input signals. The micrometer scale device operates in the GHz frequency
range and at room temperature. Our experimental results show that spin-wave
devices exploiting spin wave interference may be scaled to micrometer and
nanometer scales for potential logic circuit application.


title: Signal Processing for Pico-second Resolution Timing Measurements

abstract:
  The development of large-area homogeneous photo-detectors with sub-millimeter
path lengths for direct Cherenkov light and for secondary-electrons opens the
possibility of large time-of-flight systems for relativistic particles with
resolutions in the pico-second range. Modern ASIC techniques allow fast
multi-channel front-end electronics capable of sub-pico-second resolution
directly integrated with the photo-detectors. However, achieving resolution in
the pico-second range requires a precise knowledge of the signal generation
process in order to understand the pulse waveform, the signal dynamics, and the
noise induced by the detector itself, as well as the noise added by the
processing electronics. Using the parameters measured for fast photo-detectors
such as micro-channel plates photo-multipliers, we have simulated and compared
the time-resolutions for four signal processing techniques: leading edge
discriminators, constant fraction discriminators, multiple-threshold
discriminators and pulse waveform sampling.


title: Energy-momentum diffusion from spacetime discreteness

abstract:
  We study potentially observable consequences of spatiotemporal discreteness
for the motion of massive and massless particles. First we describe some simple
intrinsic models for the motion of a massive point particle in a fixed causal
set background. At large scales, the microscopic swerves induced by the
underlying atomicity manifest themselves as a Lorentz invariant diffusion in
energy-momentum governed by a single phenomenological parameter, and we derive
in full the corresponding diffusion equation. Inspired by the simplicity of the
result, we then derive the most general Lorentz invariant diffusion equation
for a massless particle, which turns out to contain two phenomenological
parameters describing, respectively, diffusion and drift in the particle's
energy. The particles do not leave the light cone however: their worldlines
continue to be null geodesics. Finally, we deduce bounds on the drift and
diffusion constants for photons from the blackbody nature of the spectrum of
the cosmic microwave background radiation.


title: Fractional recurrence in discrete-time quantum walk

abstract:
  Quantum recurrence theorem holds for quantum systems with discrete energy
eigenvalues and fails to hold in general for systems with continuous energy. We
show that during quantum walk process dominated by interference of amplitude
corresponding to different paths fail to satisfy the complete quantum
recurrence theorem. Due to the revival of the fractional wave packet, a
fractional recurrence characterized using quantum P\'olya number can be seen.


title:
A Simple Statistical Mechanical Approach for Studying Multilayer
  Adsorption of Interacting Polyatomics

abstract:
  A simple statistical mechanical approach for studying multilayer adsorption
of interacting polyatomic adsorbates (k-mers) has been presented. The new
theoretical framework has been developed on a generalization in the spirit of
the lattice-gas model and the classical Bragg-Williams (BWA) and quasi-chemical
(QCA) approximations. The derivation of the equilibrium equations allows the
extension of the well-known Brunauer-Emmet-Teller (BET) isotherm to more
complex systems. The formalism reproduces the classical theory for monomers,
leads to the exact statistical thermodynamics of interacting k-mers adsorbed in
one dimension, and provides a close approximation for two-dimensional systems
accounting multisite occupancy and lateral interactions in the first layer.
Comparisons between analytical data and Monte Carlo simulations were performed
in order to test the validity of the theoretical model. The study showed that:
(i) the resulting thermodynamic description obtained from QCA is significantly
better than that obtained from BWA and still mathematically handable; (ii) for
non-interacting k-mers, the BET equation leads to an underestimate of the true
monolayer volume; (iii) attractive lateral interactions compensate the effect
of the multisite occupancy and the monolayer volume predicted by BET equation
agrees very well with the corresponding true value; and (iv) repulsive
couplings between the admolecules hamper the formation of the monolayer and the
BET results are not good (even worse than those obtained in the non-interacting
case).


title: 6+1 lessons from f(R) gravity

abstract:
  There has been a recent stimulus in the study of alternative theories of
gravity lately, mostly triggered from combined motivation coming from
cosmology/astrophysics and high energy physics. Among the proposed theories,
one that has attracted much attention is f(R) gravity. It is certainly
debatable whether such a simplistic modification of General Relativity can
constitute a viable alternative theory of gravitation. However, it is quite
straightforward to see the merits of such a theory when viewed as a toy theory
whose role is to help us understand the implications and difficulties of
beyond-Einstein gravity. Under this perspective, I review some of the main
lessons we seem to have learned from the study of f(R) gravity in the recent
past.


title:
Fields of Parametrization and Optimal Affine Reparametrization of
  Rational Curves

abstract:
  In this paper we present three related results on the subject of fields of
parametrization. Let C be a rational curve over a field of characteristic zero.
Let K be a field finitely generated over Q, such that it is a field of
definition of C but not a field of parametrization. It is known that there are
quadratic extensions of K that parametrize C. First, we prove that there are
infinitely many quadratic extensions of K that are fields of parametrization of
C.
  As a consequence, we prove that the witness variety, that appear in the
context of the parametric Weil's descente method, is always a special curve
related to algebraic extensions, called hypercircle. It is possible that the
witness variety is not a hypercircle for the given extension, but for an
alternative one.
  We use these two facts to present an algorithm to solve the following optimal
reparametrization problem. Given a birational parametrization f(t) of a curve
C, compute the affine reparametrization at+b such f(at+b) has coefficients over
a field as small as possible. The main advantage of this algorithm is that it
does not need to compute any rational point on the curve.


title: Programming languages with algorithmically parallelizing problem

abstract:
  The study consists of two parts. Objective of the first part is modern
language constructions responsible for algorithmically insolvability of
parallelizing problem. Second part contains several ways to modify the
constructions to make the problem algorithmically solvable


title: Gamow-Siegert functions and Darboux-deformed short range potentials

abstract:
  Darboux-deformations of short range one-dimensional potentials are
constructed by means of Gamow-Siegert functions (resonance states). Results
include both Hermitian and non-Hermitian short range potentials which are
exactly solvable. As illustration, the method is applied to square wells and
barriers for which the transmission coefficient is a superposition of
Fock-Breit-Wigner distributions. Resonance levels are calculated in the long
lifetime limit by means of analytical and numerical approaches. The new complex
potentials behave as an optical device which both refracts and absorbs light
waves.


title: Spectral Bounds for Dirac Operators on Open Manifolds

abstract:
  We extend several classical eigenvalue estimates for Dirac operators on
compact manifolds to noncompact, even incomplete manifolds. This includes
Friedrich's estimate for manifolds with positive scalar curvature as well as
the author's estimate on surfaces.


title:
Dynamics of Galactic Disks and Mergers at z~1.6: Spatially Resolved
  Spectroscopy with Keck Laser Guide Star Adaptive Optics

abstract:
  We present 0.2" resolution near-infrared integral field spectroscopy of
H-alpha emission from six star forming galaxies at z~1.6 (look-back time of
~9.6 Gyr). These observations were obtained with OSIRIS using the Keck Laser
Guide Star Adaptive Optics system. All sources have a compact spatial extent of
~1", with an average half light radius of r=2.9 kpc and average dereddened star
formation rate of 22 Msolar per year. Based on H-alpha kinematics we find that
these six galaxies are dynamically distinguishable, and we classify them as
either merger or disk candidate systems. We find three merger systems
(HDF-BX1287, HDF-BX1315, and Q1623-BX491) with varying geometries and dynamical
properties. Three galaxies (HDF-BMZ1299, Q2343-BX344, and Q2343-BM145) are
well-fit by an inclined-disk model with low velocity residuals (20 to 46
km/sec). An average plateau velocity of v_p=185 km/sec is achieved within 1.0
kpc. The majority of observed velocity dispersions (~88 km/sec) can be
explained by the residual seeing halo, and are not intrinsic to our sources.
However, one merger and one disk candidate have high velocity dispersions (>
200 km/sec) that cannot be solely explained by beam smearing. For two disk
candidates, we detect [NII] emission and are able to map the [NII]/H-alpha
ratio on kiloparsec scales. In both cases, [NII] emission is more concentrated
than H-alpha emission (< 0.2"), and peak ratios are best explained by the
presence of an AGN. These are among the weakest known AGN at high redshift,
however their emission is strong enough to impact high redshift metallicity
studies that use nebular ratios. All disk candidates have likely completed only
a few orbital periods, and if left unperturbed are excellent candidates to
become present-day spiral galaxies.


title: Approximation by Lipschitz, analytic maps on certain Banach spaces

abstract:
  We show that on separable Banach spaces admitting a separating polynomial,
any uniformly continuous, bounded, real-valued function can be uniformly
approximated by Lipschitz, analytic maps on bounded sets.


title:
Universal spectral parameter-dependent Lax operators for the Drinfeld
  double of the dihedral group $D_3$

abstract:
  Two universal spectral parameter-dependent Lax operators are presented in
terms of the elements of the Drinfeld double $D(D_3)$ of the dihedral group
$D_3$. Applying representations of $D(D_3)$ to these yields matrix solutions of
the Yang-Baxter equation with spectral parameter.


title: Fourier Analytic Approach to Phase Estimation

abstract:
  For a unified analysis on the phase estimation, we focus on the limiting
distribution. It is shown that the limiting distribution can be given by the
absolute square of the Fourier transform of $L^2$ function whose support
belongs to $[-1,1]$. Using this relation, we study the relation between the
variance of the limiting distribution and its tail probability. As our result,
we prove that the protocol minimizing the asymptotic variance does not minimize
the tail probability. Depending on the width of interval, we derive the
estimation protocol minimizing the tail probability out of a given interval.
Such an optimal protocol is given by a prolate spheroidal wave function which
often appears in wavelet or time-limited Fourier analysis. Also, the minimum
confidence interval is derived with the framework of interval estimation that
assures a given confidence coefficient.


title:
Evidence of Systematic Bias in 2008 Presidential Polling (preliminary
  report)

abstract:
  Political polls achieve their results by sampling a small number of potential
voters rather than the population as a whole. This leads to sampling error
which most polling agencies dutifully report. But factors such as
nonrepresentative samples, question wording and nonresponse can produce
non-sampling errors. While pollsters are aware of such errors, they are
difficult to quantify and seldom reported. When a polling agency, whether by
intention or not, produces results with non-sampling errors that systematically
favor one candidate over another, then that agency's poll is biased. We
analyzed polling data for the (on-going) 2008 Presidential race, and though our
methods do not allow us to identify which agencies' polls are biased, they do
provide significant evidence that some agencies' polls are.
  We compared polls produced by major television networks with those produced
by Gallup and Rasmussen. We found that, taken as a whole, polls produced by the
networks were significantly to the left of those produced by Gallup and
Rasmussen. We used the available data to provide a tentative ordering of the
major television networks' polls from right to left. Our order was: FOX, CNN,
NBC (which partners with the Wall Street Journal), ABC (which partners with the
Washington Post), CBS (which partners with the New York Times). These results
appear to comport well with the informal perceptions of the political leanings
of these agencies.
  Our findings are preliminary, but they make a case for further research into
the causes of and remedies for polling bias.


title: Q curvature prescription; forbidden functions and the GJMS null space

abstract:
  On an even conformal manifold $(M,c)$, such that the critical GJMS operator
has non-trivial kernel, we identify and discuss the role of a finite
dimensional vector space $N(Q)$ of functions determined by the conformal
structure. Using these we describe an infinite dimensional class of functions
that cannot be the Q-curvature $Q^g$ for any $g$ in $c$. If certain functions
arise in $N(Q)$ then $Q^g$ cannot be constant for any $g$ in $c$.


title: The Pentagram map: a discrete integrable system

abstract:
  The pentagram map is a projectively natural iteration defined on polygons,
and also on objects we call twisted polygons (a twisted polygon is a map from Z
into the projective plane that is periodic modulo a projective transformation).
We find a Poisson structure on the space of twisted polygons and show that the
pentagram map relative to this Poisson structure is completely integrable in
the sense of Arnold-Liouville. For certain families of twisted polygons, such
as those we call universally convex, we translate the integrability into a
statement about the quasi-periodic motion for the dynamics of the pentagram
map. We also explain how the pentagram map, in the continuous limit,
corresponds to the classical Boussinesq equation. The Poisson structure we
attach to the pentagram map is a discrete version of the first Poisson
structure associated with the Boussinesq equation.


title:
Fragment properties of fragmenting heavy nuclei produced in central and
  semi-peripheral collisions

abstract:
  Fragment properties of hot fragmenting sources of similar sizes produced in
central and semi-peripheral collisions are compared in the excitation energy
range 5-10 AMeV. For semi-peripheral collisions a method for selecting compact
quasi-projectiles sources in velocity space similar to those of fused systems
(central collisions) is proposed. The two major results are related to
collective energy. The weak radial collective energy observed for
quasi-projectile sources is shown to originate from thermal pressure only. The
larger fragment multiplicity observed for fused systems and their more
symmetric fragmentation are related to the extra radial collective energy due
to expansion following a compression phase during central collisions. A first
attempt to locate where the different sources break in the phase diagram is
proposed.


title:
Science with UT's Dichroic-Mirror Camera (DMC), 15-band simultaneous
  imager

abstract:
  We introduce the Dichroic-Mirror Camera (DMC), an instrument developed at the
University of Tokyo which is capable of performing simultaneous imaging in
fifteen bands. The main feature of the DMC is the dichroic mirrors, which split
incoming light into red and blue components. Combination of dichroic mirrors
split light from the telescope focus into fifteen intermediate-width bands
across 390 -- 950 nm. The fifteen bands of DMC provide measurements of the
object's spectral energy distribution (SED) at fifteen wavelength points.
During May -- June 2007 and March 2008, observing run of the DMC was carried
out at Higashi-Hiroshima Observatory, Japan. We observed several objects i.e.
planets, asteroids, standard stars & star clusters, planetary nebulae,
galaxies, and supernovae. We describe several early scientific results from the
DMC.


title:
Measurements of the observed cross sections for e+e -> exclusive light
  hadrons containing K^S_0 meson at \sqrt{s} = 3.773 and 3.650 GeV

abstract:
  By analyzing the data sets of 17.3 pb$^{-1}$ taken at $\sqrt s= 3.773$ GeV
and of 6.5 pb$^{-1}$ taken at $\sqrt s= 3.650$ GeV with the BES-II detector at
the BEPC collider, we measure the observed cross sections for the exclusive
light hadron final states of $K_S^0K^-\pi^+$, $K_S^0K^-\pi^+\pi^0$,
$K_S^0K^-\pi^+\pi^+\pi^-$, $K_S^0K^-\pi^+\pi^+\pi^-\pi^0$,
$K_S^0K^-\pi^+\pi^+\pi^+\pi^-\pi^-$ and $K_S^0K^-\pi^+\pi^0\pi^0$ produced in
$e^+ e^-$ annihilation at the two energy points. We set the upper limits on the
observed cross sections and the branching fractions for $\psi(3770)$ decay to
these final states at 90% C.L..


title: Charmed baryon in a string model

abstract:
  Charm spectroscopy has studied under a string model. Charmed baryons are
composed of diquark and charm quark which are connected by a constant tension.
In a diquark picture, the quantum numbers $J^P$ of confirmed baryons are well
assigned. We give energy predictions for the first and second orbital
excitations. We see some correspondences with the experimental data. Meanwhile,
we have obtained diquark masses in the background of charm quark which satisfy
a splitting relation based on spin-spin interaction.


title:
The BCS Gap Equation on a Banach Space Consisting of Functions both of
  the Temperature and of the Wave Vector

abstract:
  In previous mathematical studies of the BCS gap equation of
superconductivity, the gap function was regarded as an element of a space
consisting of functions of the wave vector only. But we regard it as an element
of a Banach space consisting of functions both of the temperature and of the
wave vector. On the basis of the implicit function theorem we first show that
there is a unique solution of class $C^2$ with respect to the temperature, to
the simplified gap equation obtained from the BCS gap equation. We then regard
the BCS gap equation as a nonlinear integral equation on the Banach space
above, and show that there is a unique solution to the BCS gap equation on the
basis of the Schauder fixed-point theorem. We find that the solution to the BCS
gap equation is continuous with respect to both the temperature and the wave
vector, and that the solution is approximated by a function of class $C^2$ with
respect to both the temperature and the wave vector. Moreover, the solution to
the BCS gap equation is shown to reduce to the solution to the simplified gap
equation under a certain condition.


title:
Measurements of the observed cross sections for $e^+e^-\to$ exclusive
  light hadrons containing $\pi^0\pi^0$ at $\sqrt s= 3.773$, 3.650 and 3.6648
  GeV

abstract:
  By analyzing the data sets of 17.3, 6.5 and 1.0 pb$^{-1}$ taken,
respectively, at $\sqrt s= 3.773$, 3.650 and 3.6648 GeV with the BES-II
detector at the BEPC collider, we measure the observed cross sections for
$e^+e^-\to \pi^+\pi^-\pi^0\pi^0$, $K^+K^-\pi^0\pi^0$, $2(\pi^+\pi^-\pi^0)$,
$K^+K^-\pi^+\pi^-\pi^0\pi^0$ and $3(\pi^+\pi^-)\pi^0\pi^0$ at the three energy
points. Based on these cross sections we set the upper limits on the observed
cross sections and the branching fractions for $\psi(3770)$ decay into these
final states at 90% C.L..


title: ac-driven Brownian motors: a Fokker-Planck treatment

abstract:
  We consider a primary model of ac-driven Brownian motors, i.e., a classical
particle placed in a spatial-time periodic potential and coupled to a heat
bath. The effects of fluctuations and dissipations are studied by a
time-dependent Fokker-Planck equation. The approach allows us to map the
original stochastic problem onto a system of ordinary linear algebraic
equations. The solution of the system provides complete information about
ratchet transport, avoiding such disadvantages of direct stochastic
calculations as long transients and large statistical fluctuations. The
Fokker-Planck approach to dynamical ratchets is instructive and opens the space
for further generalizations.


title: Anticipatory synchronization with variable time delay and reset

abstract:
  A method to synchronize two chaotic systems with anticipation or lag, coupled
in the drive response mode, is proposed. The coupling involves variable delay
with three time scales. The method has the advantage that synchronization is
realized with intermittant information about the driving system at intervals
fixed by a reset time. The stability of the synchronization manifold is
analyzed with the resulting discrete error dynamics. The numerical calculations
in standard systems like the Rossler and Lorenz systems are used to demonstrate
the method and the results of the analysis.


title: Intergalactic dust and its photoelectric heating

abstract:
  We have examined the dust photoelectric heating in the intergalactic medium
(IGM). The heating rate in a typical radiation field of the IGM is represented
by $\Gamma_{\rm pe} = 1.2\times10^{-34}$ erg s$^{-1}$ cm$^{-3}$ $({\cal
D}/10^{-4})(n_{\rm H}/10^{-5} {\rm cm^{-3}})^{4/3} (J_{\rm L}/10^{-21} {\rm erg
s^{-1} cm^{-2} Hz^{-1} sr^{-1}})^{2/3} (T/10^4 {\rm K})^{-1/6}$, where ${\cal
D}$ is the dust-to-gas mass ratio, $n_{\rm H}$ is the hydrogen number density,
$J_{\rm L}$ is the mean intensity at the hydrogen Lyman limit of the background
radiation, and $T$ is the gas temperature, if we assume the new X-ray
photoelectric yield model by Weingartner et al. (2006) and the dust size
distribution in the Milky Way by Mathis, Rumpl, & Nordsieck (1977). This
heating rate dominates the HI and HeII photoionization heating rates when the
hydrogen number density is less than $\sim10^{-6}$ cm$^{-3}$ if ${\cal
D}=10^{-4}$ which is 1% of that in the Milky Way, although the heating rate is
a factor of 2--4 smaller than that with the old yield model by Weingartner &
Draine (2001). The grain size distribution is very important. If only large
($\ge0.1$ $\mu$m) grains exist in the IGM, the heating rate is reduced by a
factor of $\simeq5$. Since the dust heating is more efficient in a lower
density medium relative to the photoionization heating, it may cause an
inverted temperature--density relation in the low density IGM suggested by
Bolton et al. (2008). Finally, we have found that the dust heating is not very
important in the mean IGM before the cosmic reionization.


title:
Conjugation-free geometric presentations of fundamental groups of
  arrangements

abstract:
  We introduce the notion of a conjugation-free geometric presentation for a
fundamental group of a line arrangement's complement, and we show that the
fundamental groups of the following family of arrangements have a
conjugation-free geometric presentation: A real arrangement L, whose graph of
multiple points is a union of disjoint cycles, has no line with more than two
multiple points, and where the multiplicities of the multiple points are
arbitrary.
  We also compute the exact group structure (by means of a semi-direct product
of groups) of the arrangement of 6 lines whose graph consists of a cycle of
length 3, and all the multiple points have multiplicity 3.


title: Concatenated Control Sequences based on Optimized Dynamic Decoupling

abstract:
  Two recent developments in quantum control, concatenation and optimization of
pulse intervals, are combined to yield a strategy to suppress unwanted
couplings in quantum systems to high order. Longitudinal relaxation and
transverse dephasing can be suppressed so that systems with a small splitting
between their energy levels can be kept isolated from their environment. The
required number of pulses grows exponentially with the desired order but is
only the square root of the number needed if only concatenation is used. An
approximate scheme even brings the number down to polynomial growth. The
approach is expected to be useful for quantum information and for
high-precision nuclear magnetic resonance.


title: Galaxy Interactions, Star Formation History, and Bulgeless Galaxies

abstract:
  Hierarchical Lambda CDM models provide a successful paradigm for the growth
of dark matter on large scales, but they face important challenges in
predicting how the baryonic components of galaxies evolve. I present
constraints on two aspects of this evolution: (1) The interaction history of
galaxies over the last 7 Gyr and the impact of interactions on their star
formation properties, based on Jogee et al. (2008a,b); (2) Constraints on the
origin of bulges in hierarchical models and the challenge posed in accounting
for galaxies with low bulge-to-total ratios, based on Weinzirl, Jogee, Khochar,
Burkert, and Kormendy (2008, hereafter WJKBK08)


title: A rigidity theorem for quaternionic Kaehler structures

abstract:
  We study the moduli space of quaternionic Kaehler structures on a compact
manifold of dimension 4n (n>2) from a point of view of Riemannian geometry, not
twistor theory. Then we obtain a rigidity theorem for quaternionic Kaehler
structures of nonzero scalar curvature by observing the moduli space.


title:
Jack deformations of Plancherel measures and traceless Gaussian random
  matrices

abstract:
  We study random partitions $\lambda=(\lambda_1,\lambda_2,...,\lambda_d)$ of
$n$ whose length is not bigger than a fixed number $d$. Suppose a random
partition $\lambda$ is distributed according to the Jack measure, which is a
deformation of the Plancherel measure with a positive parameter $\alpha>0$. We
prove that for all $\alpha>0$, in the limit as $n \to \infty$, the joint
distribution of scaled $\lambda_1,..., \lambda_d$ converges to the joint
distribution of some random variables from a traceless Gaussian
$\beta$-ensemble with $\beta=2/\alpha$. We also give a short proof of Regev's
asymptotic theorem for the sum of $\beta$-powers of $f^\lambda$, the number of
standard tableaux of shape $\lambda$.


title: New Primordial-Magnetic-Field Limit from The Latest LIGO S5 data

abstract:
  Since the energy momentum tensor of a magnetic field always contains a spin-2
component in its anisotropic stress, stochastic primordial magnetic field (PMF)
in the early universe must generate stochastic gravitational wave (GW)
background. This process will greatly affect the relic gravitational wave
(RGW), which is one of major scientific goals of the laser interferometer GW
detections. Recently, the fifth science (S5) run of laser interferometer
gravitational-wave observatory (LIGO) gave a latest upper limit
$\Omega_{GW}<6.9\times10^{-6}$ on the RGW background. Utilizing this upper
limit, we derive new PMF Limits: for a scale of galactic cluster $\lambda=1$
Mpc, the amplitude of PMF, that produced by the electroweak phase transition
(EPT), has to be weaker than $B_{\lambda} \leq 4\times 10^{-7}$ Gauss; for a
scale of supercluster $\lambda=100$ Mpc, the amplitude of PMF has to be weaker
than $B_{\lambda} \leq 9\times 10^{-11}$ Gauss. In this manner, GW observation
has potential to make interesting contributions to the study of primordial
magnetic field.


title: Conformally Osserman manifolds

abstract:
  An algebraic curvature tensor is called Osserman if the eigenvalues of the
associated Jacobi operator are constant on the unit sphere. A Riemannian
manifold is called conformally Osserman if its Weyl conformal curvature tensor
at every point is Osserman. We prove that a conformally Osserman manifold of
dimension $n \ne 3, 4, 16$ is locally conformally equivalent either to a
Euclidean space or to a rank-one symmetric space.


title: Stationary Phase and the Theory of Measurement -- 1/N expansion --

abstract:
  The measuring process is studied, where a macroscopic number N of particles
in the detector interact with the object. The macrovariable accompanies the
stationary phase in the path-integral form, which is in one-to-one
correspondence with the eigen-value of the object operator O to be measured.
When N goes to infinity, the fluctuation of the object between different
eigenvalues of O is suppressed, frozen to one the same state while the detector
is on. A model is studied which produces the ideal result when N is infinite,
and the correction terms are calculated in powers of 1/N. It is identical to
the expansion including the fluctuation of the object successively.


title:
Coexistence of Antiferromagnetism and Superconductivity in
  PrFeAsO$_{1-\delta}$

abstract:
  A high-quality PrFeAsO$_{1-\delta}$ single crystal ($T_{\rm c}=44$ K) has
been investigated by the magnetic torque. Antiferromagnetism of the Pr$^{3+}$
ions was found to coexist with superconductivity in PrFeAsO$_{1-\delta}$ at
temperatures below $T_\mathrm{N}=14$ K. We predict a magnetic structure that is
not in accordance with earlier neutron studies performed using polycrystalline
nonsuperconducting specimens. As the temperature decreases, the superconducting
anisotropy $\gamma\sim 4$ of PrFeAsO$_{1-\delta}$ increases near $T_c$ and
tends to decrease slightly at lower temperatures.


title:
Effect of external electric field on the charge density waves in one
  dimensional Hubbard superlattices

abstract:
  We have studied the ground state of the one dimensional Hubbard superlattice
structures with different unit cell sizes in the presence of electric field.
Self consistent Hartree-Fock approximation calculation is done in the weak to
intermediate interaction regime. Studying the charge gap at the Fermi level and
the charge density structure factor, we get an idea how the charge modulation
on the superlattice is governed by the competition between the electronic
correlation and the external electric field.


title:
Finite-frequency dynamics of vortex loops at the $^4$He superfluid phase
  transition

abstract:
  The finite-frequency dynamics of the $^4$He superfluid phase transition can
be formulated in terms of the response of thermally excited vortex loops to an
oscillating flow field. The key parameter is the Hausdorff fractal dimension
$d_H$ of the loops, which affects the dynamics because the frictional force on
a loop is proportional to the total perimeter $P$ of the loop, which varies as
$P \sim a^{d_H}$ where $a$ is the loop diameter. Solving the 3D Fokker-Planck
equation for the loop response at frequency $\omega $ yields a superfluid
density which varies at $T_{\lambda}$ as $\omega^{1/(d_H -1)}$. This power-law
variation with $\omega$ agrees with the scaling form found by Fisher, Fisher,
and Huse, since the dynamic exponent $z$ is identified as $z = d_H-1$. Flory
scaling for the self-avoiding loops gives a fractal dimension in terms of the
space dimension $d$ as $d_H = (d+2)/2$, yielding $z = d/2 = 3/2$ for d = 3, in
complete agreement with dynamic scaling.


title:
Resource Requirements for Fault-Tolerant Quantum Simulation: The
  Transverse Ising Model Ground State

abstract:
  We estimate the resource requirements, the total number of physical qubits
and computational time, required to compute the ground state energy of a 1-D
quantum Transverse Ising Model (TIM) of N spin-1/2 particles, as a function of
the system size and the numerical precision. This estimate is based on
analyzing the impact of fault-tolerant quantum error correction in the context
of the Quantum Logic Array (QLA) architecture. Our results show that due to the
exponential scaling of the computational time with the desired precision of the
energy, significant amount of error correciton is required to implement the TIM
problem. Comparison of our results to the resource requirements for a
fault-tolerant implementation of Shor's quantum factoring algorithm reveals
that the required logical qubit reliability is similar for both the TIM problem
and the factoring problem.


title:
Adsorption properties and third sound propagation in superfluid $^4$He
  films on carbon nanotubes

abstract:
  We consider the adsorption properties of superfluid $^4$He films on carbon
nanotubes. One major factor in the adsorption is the surface tension force
arising from the very small diameter of the nanotubes. Calculations show that
surface tension keeps the film thickness on the tubes very thin even when the
helium vapor is increased to the saturated pressure. The weakened Van der Waals
force due to the cylindrical geometry also contributes to this. Both of these
effects act to lower the predicted velocity of third sound propagation along
the tubes. It does not appear that superfluidity will be possible on
single-walled nanotubes of diameter about one nm, since the film thickness is
less than 3 atomic layers even at saturation. Superfluidity is possible on
larger-diameter nanotube bundles and multi-walled nanotubes, however. We have
observed third sound signals on nanotube bundles of average diameter 5 nm which
are sprayed onto a Plexiglass surface, forming a network of tubes.


title:
Operator product expansion for B-meson distribution amplitude and
  dimension-5 HQET operators

abstract:
  When the bilocal heavy-quark effective theory (HQET) operator for the B-meson
distribution amplitude has a light-like distance t between the quark and
antiquark fields, the scale \sim 1/t separates the UV and IR regions, which
induce the cusp singularity in radiative corrections and the mixing of
multiparticle states in nonperturbative corrections, respectively. We treat
these notorious UV and IR behaviors simultaneously using the operator product
expansion, with the local operators of dimension $d \le 5$ and radiative
corrections at order \alpha_s for the corresponding Wilson coefficients. The
result is derived in the coordinate space, which manifests the Wilson
coefficients with Sudakov-type double logarithms and the higher-dimensional
operators with additional gluons. This result yields the B-meson distribution
amplitude for t less than \sim 1 GeV^{-1}, in terms of $\bar{\Lambda}=m_B -
m_b$ and the two additional HQET parameters as matrix elements of dimension-5
operators. The impact of these novel HQET parameters on the integral relevant
to exclusive B decays, \lambda_B, is also discussed.


title: Simultaneous Binary Collisions for Collinear Four-Body Problem

abstract:
  In this paper, we use canonical transformations to collectively analytically
continue the singularities of the simultaneous binary collision solutions for
the collinear four- body problem in both the decoupled case and the coupled
case. All the solutions are found and more importantly, we describe the
relationship between the decoupled solutions and the coupled solutions.


title:
Suzaku observations of metallicity distribution in the intracluster
  medium of the NGC 5044 group

abstract:
  The metallicity distribution in the intracluster medium of the NGC 5044 group
was studied up to 0.3 r_180 using the XIS instrument on board the Suzaku
satellite. Abundances of O, Mg, Si, S, and Fe were measured with high accuracy.
The region within a radius of 0.05 r_180 from the center shows approximately
solar abundances of Mg, Si, S, and Fe, while the O/Fe ratio is about 0.5--0.6
in solar units. In the outer region, the Fe abundance gradually drops to 0.3
solar. Radial abundance profiles of Mg, Si and S are similar to that of Fe,
while that of O seems to be flatter. At r>0.05 r_180, the mass density profile
of O differs from that of Fe, showing a shoulder-like structure that traces the
luminosity density profile of galaxies. The mass-to-light ratios for O and Fe
in NGC 5044 are one of the largest among groups of galaxies, but they are still
smaller than those in rich clusters. These abundance features probably reflect
the metal enrichment history of this relaxed group hosting a giant elliptical
galaxy in the center.


title: Temporal Difference Updating without a Learning Rate

abstract:
  We derive an equation for temporal difference learning from statistical
principles. Specifically, we start with the variational principle and then
bootstrap to produce an updating rule for discounted state value estimates. The
resulting equation is similar to the standard equation for temporal difference
learning with eligibility traces, so called TD(lambda), however it lacks the
parameter alpha that specifies the learning rate. In the place of this free
parameter there is now an equation for the learning rate that is specific to
each state transition. We experimentally test this new learning rule against
TD(lambda) and find that it offers superior performance in various settings.
Finally, we make some preliminary investigations into how to extend our new
temporal difference algorithm to reinforcement learning. To do this we combine
our update equation with both Watkins' Q(lambda) and Sarsa(lambda) and find
that it again offers superior performance without a learning rate parameter.


title:
The exact probability distribution of saturating states in random
  sequential adsorption

abstract:
  We consider the non-overlapping irreversible random sequential adsorption
(RSA) process on one-dimensional finite line, which is known also as the car
parking process. The probability of each coverage in saturating states is
analytically and exactly obtained. In the derivation, a new representation of
states in RSA process is introduced, which effectively works to make the
calculation clear and simple.


title:
Reconstructing Extended Perfect Binary One-Error-Correcting Codes from
  Their Minimum Distance Graphs

abstract:
  The minimum distance graph of a code has the codewords as vertices and edges
exactly when the Hamming distance between two codewords equals the minimum
distance of the code. A constructive proof for reconstructibility of an
extended perfect binary one-error-correcting code from its minimum distance
graph is presented. Consequently, inequivalent such codes have nonisomorphic
minimum distance graphs. Moreover, it is shown that the automorphism group of a
minimum distance graph is isomorphic to that of the corresponding code.


title: Lattice QCD: a critical status report

abstract:
  The substantial progress that has been achieved in lattice QCD in the last
years is pointed out. I compare the simulation cost and systematic effects of
several lattice QCD formulations and discuss a number of topics such as lattice
spacing scaling, applications of chiral perturbation theory, non-perturbative
renormalization and finite volume effects. Additionally, the importance of
demonstrating universality is emphasized.


title: Two-time quantum transport and quantum diffusion

abstract:
  Based on the nonequilibrium Green's function technique, a unified theory is
developed that covers quantum transport and quantum diffusion in bulk
semiconductors on the same footing. This approach, which is applicable to
transport via extended and localized states, extends previous
semi-phenomenological studies and puts them on a firm microscopic basis. The
approach is sufficiently general and applies not only to well-studied quantum
transport problems, but also to models, in which the Hamiltonian does not
commute with the dipole operator. It is shown that, even for the unified
treatment of quantum transport and quantum diffusion in homogeneous systems,
all quasi-momenta of the carrier distribution function are present and fulfill
their specific function. Particular emphasis is put on the double-time nature
of quantum kinetics. To demonstrate the existence of robust macroscopic
transport effects that have a true double-time character, a phononless
steady-state current is identified that appears only beyond the generalized
Kadanoff-Baym ansatz.


title:
On the Possibility of Learning in Reactive Environments with Arbitrary
  Dependence

abstract:
  We address the problem of reinforcement learning in which observations may
exhibit an arbitrary form of stochastic dependence on past observations and
actions, i.e. environments more general than (PO)MDPs. The task for an agent is
to attain the best possible asymptotic reward where the true generating
environment is unknown but belongs to a known countable family of environments.
We find some sufficient conditions on the class of environments under which an
agent exists which attains the best asymptotic reward for any environment in
the class. We analyze how tight these conditions are and how they relate to
different probabilistic assumptions known in reinforcement learning and related
fields, such as Markov Decision Processes and mixing conditions.


title: Chemical Diversity in High-Mass Star Formation

abstract:
  Massive star formation exhibits an extremely rich chemistry. However, not
much evolutionary details are known yet, especially at high spatial resolution.
Therefore, we synthesize previously published Submillimeter Array
high-spatial-resolution spectral line observations toward four regions of
high-mass star formation that are in various evolutionary stages with a range
of luminosities. Estimating column densities and comparing the spatially
resolved molecular emission allows us to characterize the chemical evolution in
more detail. Furthermore, we model the chemical evolution of massive warm
molecular cores to be directly compared with the data. The four regions reveal
many different characteristics. While some of them, e.g., the detection rate of
CH3OH, can be explained by variations of the average gas temperatures, other
features are attributed to chemical effects. For example, C34S is observed
mainly at the core-edges and not toward their centers because of
temperature-selective desorption and successive gas-phase chemistry reactions.
Most nitrogen-bearing molecules are only found toward the hot molecular cores
and not the earlier evolutionary stages, indicating that the formation and
excitation of such complex nitrogen-bearing molecules needs significant heating
and time to be fully developed. Furthermore, we discuss the observational
difficulties to study massive accretion disks in the young deeply embedded
phase of massive star formation. The general potential and limitations of such
kind of dataset are discussed, and future directions are outlined. The analysis
and modeling of this source sample reveals many interesting features toward a
chemical evolutionary sequence. However, it is only an early step, and many
observational and theoretical challenges in that field lie ahead.


title:
A remark on the uniqueness of positive solutions to semilinear elliptic
  equations with double power nonlinearities

abstract:
  We consider the uniqueness of positive solutions to semilinear elliptic
equations with double power nonlinearities. We deduce the uniqueness from the
argument in the classical paper by Peletier and Serrin, thereby recovering a
part of the uniqueness result of Ouyang and Shi.


title: Simulating acceleration and radiation processes in X-ray binaries

abstract:
  The high energy emission of microquasars is thought to originate from high
energy particles. Depending on the spectral state, the distribution of these
particles can be thermal with a high temperature (typically 100 keV) or
non-thermal and extending to even higher energy. The properties of high energy
plasmas are governed by a rich microphysics involving particle-particle
collisions and particles-photons interactions.
  We present a new code developed to address the evolution of relativistic
plasmas. This one-zone code focuses on the microphysics and solves the coupled
kinetic equations for particles and photons, including Compton scattering,
synchrotron emission and absorption, pair production and annihilation,
bremsstrahlung emission and absorption, Coulomb interactions, and prescriptions
for additional particle acceleration and heating. It can in particular describe
mechanisms such a thermalisation by synchrotron self-absorption and Coulomb
collisions.
  Using the code, we investigate whether various acceleration processes, namely
thermal heating, non-thermal acceleration and stochastic acceleration, can
reproduce the different spectral states of microquasars. Premilinary results
are presented.


title: Radiation processes around accreting black holes

abstract:
  Accreting sources such as AGN, X-ray binaries or gamma-ray bursts are known
to be strong, high energy emitters. The hard emission is though to originate
from plasmas of thermal and/or non-thermal high energy particles. Not only does
this emission allow to probe the unique properties of the matter in an extreme
environment, but it also has a crucial backreaction on the energetics and the
dynamics of the emitting medium itself. Understanding interactions between
radiation and matter has become a key issue in the modelling of high energy
sources. Although most cross sections are well known, they are quite complex
and the way all processes couple non-linearly is still an open issue.
  We present a new code that solves the local, kinetic evolution equations for
distributions of electrons, positrons and photons, interacting by radiation
processes such as self-absorbed synchrotron and brems-strahlung radiation,
Compton scattering, pair production/annihilation, and by Coulomb collisions.
The code is very general and aimed to modelled various high energy sources. As
an application, we study the spectral states of X-ray binaries, including
thermalization by Coulomb collisions and synchrotron self-absorption. It is
found that the low-hard and high-soft states can be modelled with different
illumination but the same non-thermal acceleration mechanism.


title: Forcings constructed along morasses

abstract:
  In a previous paper, we introduced a way of constructing a forcing along a
simplified gap-1 morass such that the forcing satisfies a chain condition. Now,
we generalize this to gap-2 morasses. As an application, we prove that GCH is
consistent with the existence of a 0-dimensional Hausdorff topology on
$\omega_3$ which has spread $\omega_1$.


title:
Diffusion Monte Carlo study of a valley degenerate electron gas and
  application to quantum dots

abstract:
  A many-flavor electron gas (MFEG) in a semiconductor with a valley degeneracy
ranging between 6 and 24 was analyzed using diffusion Monte Carlo (DMC)
calculations. The DMC results compare well with an analytic expression derived
by one of us [Phys. Rev. B 78, 035111 (2008)] for the total energy to within 1%
over an order of magnitude range of density, which increases with valley
degeneracy. For Bi2Te3 (six-fold valley degeneracy) the applicable charge
carrier densities are between 7*10^19cm^{-3} and 2*10^20cm^{-3}. DMC
calculations distinguished between an exact and a useful approximate expression
for the 24-fold degenerate MFEG polarizability for wave numbers 2p_F<q<7p_F.
The analytical result for the MFEG is generalized to inhomogeneous systems by
means of a gradient correction, the validity range of this approach is
obtained. Employed within a density functional theory calculation this
approximation compares well with DMC results for a quantum dot.


title: Pseudo-Hermitian Representation of Quantum Mechanics

abstract:
  A diagonalizable non-Hermitian Hamiltonian having a real spectrum may be used
to define a unitary quantum system, if one modifies the inner product of the
Hilbert space properly. We give a comprehensive and essentially self-contained
review of the basic ideas and techniques responsible for the recent
developments in this subject. We provide a critical assessment of the role of
the geometry of the Hilbert space in conventional quantum mechanics to reveal
the basic physical principle motivating our study. We then offer a survey of
the necessary mathematical tools and elaborate on a number of relevant issues
of fundamental importance. In particular, we discuss the role of the antilinear
symmetries such as PT, the true meaning and significance of the charge
operators C and the CPT-inner products, the nature of the physical observables,
the equivalent description of such models using ordinary Hermitian quantum
mechanics, the pertaining duality between local-non-Hermitian versus
nonlocal-Hermitian descriptions of their dynamics, the corresponding classical
systems, the pseudo-Hermitian canonical quantization scheme, various methods of
calculating the (pseudo-) metric operators, subtleties of dealing with
time-dependent quasi-Hermitian Hamiltonians and the path-integral formulation
of the theory, and the structure of the state space and its ramifications for
the quantum Brachistochrone problem. We also explore some concrete physical
applications of the abstract concepts and tools that have been developed in the
course of this investigation. These include applications in nuclear physics,
condensed matter physics, relativistic quantum mechanics and quantum field
theory, quantum cosmology, electromagnetic wave propagation, open quantum
systems, magnetohydrodynamics, quantum chaos, and biophysics.


title:
Regularities in the frequency spacings of Delta Scuti stars and the s-f
  Diagram

abstract:
  Statistical analyses of several Delta Scuti stars (FG Vir, 44 Tau, BL Cam and
others) show that the photometrically observed frequencies cluster around the
frequencies of the radial modes over many radial orders. The observed
regularities can be partly explained by modes trapped in the stellar envelope.
This mode selection mechanism was already proposed by Dziembowski & Krolikowska
(1990) and was shown to be efficient for l=1 modes. New pulsation model
calculations confirm the observed regularities. We present the s-f diagram,
which compares the average separation of the radial frequencies (s) with the
frequency of the lowest unstable radial mode (f). The diagram provides an
estimate for the log g value of the observed star, if we assume that the
centers of the observed frequency clusters correspond to the radial mode
frequencies. This assumption is confirmed by examples of well-studied Delta
Scuti variables in which radial modes were definitely identified.


title: A theory of generalized Donaldson-Thomas invariants

abstract:
  Let X be a Calabi-Yau 3-fold over C. The Donaldson-Thomas invariants of X are
integers DT^a(t) which count stable sheaves with Chern character a on X, with
respect to a Gieseker stability condition t. They are defined only for Chern
characters a for which there are no strictly semistable sheaves on X. They have
the good property that they are unchanged under deformations of X. Their
behaviour under change of stability condition t was not understood until now.
  This book defines and studies a generalization of Donaldson-Thomas
invariants. Our new invariants \bar{DT}^a(t) are rational numbers, defined for
all Chern characters a, and are equal to DT^a(t) if there are no strictly
semistable sheaves in class a. They are deformation-invariant, and have a known
transformation law under change of stability condition.
  To prove all this we study the local structure of the moduli stack M of
coherent sheaves on X. We show that an atlas for M may be written locally as
Crit(f) for f a holomorphic function on a complex manifold, and use this to
deduce identities on the Behrend function of M.
  We compute our invariants in examples, and make a conjecture about their
integrality properties. We extend the theory to abelian categories of
representations of a quiver with relations coming from a superpotential, and
connect our ideas with Szendroi's "noncommutative Donaldson-Thomas invariants"
and work by Reineke and others.
  This book is surveyed in the paper arXiv:0910.0105.


title: On semilinear elliptic equations with global coupling

abstract:
  We consider nonlinear elliptic equations which contains global coupling as a
nonlinear term. We classify the existence of all possible positive solutions to
this problem.


title:
Kaltofen's division-free determinant algorithm differentiated for matrix
  adjoint computation

abstract:
  Kaltofen has proposed a new approach in 1992 for computing matrix
determinants without divisions. The algorithm is based on a baby steps/giant
steps construction of Krylov subspaces, and computes the determinant as the
constant term of a characteristic polynomial. For matrices over an abstract
ring, by the results of Baur and Strassen, the determinant algorithm, actually
a straight-line program, leads to an algorithm with the same complexity for
computing the adjoint of a matrix. However, the latter adjoint algorithm is
obtained by the reverse mode of automatic differentiation, hence somehow is not
"explicit". We present an alternative (still closely related) algorithm for the
adjoint thatcan be implemented directly, we mean without resorting to an
automatic transformation. The algorithm is deduced by applying program
differentiation techniques "by hand" to Kaltofen's method, and is completely
decribed. As subproblem, we study the differentiation of programs that compute
minimum polynomials of lineraly generated sequences, and we use a lazy
polynomial evaluation mechanism for reducing the cost of Strassen's avoidance
of divisions in our case.


title: Relative Oscillation Theory for Jacobi Matrices

abstract:
  We develop relative oscillation theory for Jacobi matrices which, rather than
counting the number of eigenvalues of one single matrix, counts the difference
between the number of eigenvalues of two different matrices. This is done by
replacing nodes of solutions associated with one matrix by weighted nodes of
Wronskians of solutions of two different matrices.


title: Optical Anisotropy of Electronic Excitations in Elliptical Quantum Dots

abstract:
  The authors report that anisotropic confining potentials in laterally-coupled
semiconductor quantum dots (QDs) have large impacts in optical transitions and
energies of inter-shell collective electronic excitations. The observed
anisotropies are revealed by inelastic light scattering as a function of the
in-plane direction of light polarization and can be finely controlled by
modifying the geometrical shape of the QDs. These experiments show that the
tuning of the QD confinement potential offers a powerful method to manipulate
electronic states and far-infrared inter-shell optical transitions in quantum
dots.


title: Multi-Avalanche Correlations in Directed Sandpile Models

abstract:
  Multiple avalanches, initiated by simultaneously toppling neighbouring sites,
are studied in three different directed sandpile models. It is argued that,
while the single avalanche exponents are different for the three models, a
suitably defined two-avalanche distribution has identical exponents. The origin
of this universality is traced to particle conservation.


title: Is the spectrum of highly excited mesons purely coulombian?

abstract:
  We show that a static central potential may provide a precise description of
highly excited light unflavoured mesons. Due to string breaking this potential
becomes of chromoelectric type at sufficiently large quark-antiquark distances
giving rise to a coulombian spectrum. The same conclusion can be inferred for
any other meson sector through a straightforward extension of our analysis.