title:
A microfluidic device based on droplet storage for screening solubility
  diagrams

abstract:
  This work describes a new microfluidic device developed for rapid screening
of solubility diagrams. In several parallel channels, hundreds of
nanoliter-volume droplets of a given solution are first stored with a gradual
variation in the solute concentration. Then, the application of a temperature
gradient along these channels enables us to read directly and quantitatively
phase diagrams, concentration vs. temperature. We show, using a solution of
adipic acid, that we can measure ten points of the solubility curve in less
than 1 hr and with only 250 $\mu$L of solution.


title: Composite fermion wave functions as conformal field theory correlators

abstract:
  It is known that a subset of fractional quantum Hall wave functions has been
expressed as conformal field theory (CFT) correlators, notably the Laughlin
wave function at filling factor $\nu=1/m$ ($m$ odd) and its quasiholes, and the
Pfaffian wave function at $\nu=1/2$ and its quasiholes. We develop a general
scheme for constructing composite-fermion (CF) wave functions from conformal
field theory. Quasiparticles at $\nu=1/m$ are created by inserting anyonic
vertex operators, $P_{\frac{1}{m}}(z)$, that replace a subset of the electron
operators in the correlator. The one-quasiparticle wave function is identical
to the corresponding CF wave function, and the two-quasiparticle wave function
has correct fractional charge and statistics and is numerically almost
identical to the corresponding CF wave function. We further show how to exactly
represent the CF wavefunctions in the Jain series $\nu = s/(2sp+1)$ as the CFT
correlators of a new type of fermionic vertex operators, $V_{p,n}(z)$,
constructed from $n$ free compactified bosons; these operators provide the CFT
representation of composite fermions carrying $2p$ flux quanta in the $n^{\rm
th}$ CF Landau level. We also construct the corresponding quasiparticle- and
quasihole operators and argue that they have the expected fractional charge and
statistics. For filling fractions 2/5 and 3/7 we show that the chiral CFTs that
describe the bulk wave functions are identical to those given by Wen's general
classification of quantum Hall states in terms of $K$-matrices and $l$- and
$t$-vectors, and we propose that to be generally true. Our results suggest a
general procedure for constructing quasiparticle wave functions for other
fractional Hall states, as well as for constructing ground states at filling
fractions not contained in the principal Jain series.


title: $\Bz\to\pip\pim\piz$ Time Dependent Dalitz analysis at BaBar

abstract:
  I present here results of a time-dependent analysis of the Dalitz structure
of neutral $B$ meson decays to
  $\pip\pim\piz$ from a dataset of 346 million $B \bar B$ pairs collected at
the $\Upsilon(4S)$ center of mass energy by the BaBar detector at the SLAC
PEP-II $e^+e^-$ accelerator. No significant CP violation effects are observed
and 68% confidence interval is derived on the weak angle $\alpha$ to be
[75$^o$,152$^o$]


title:
New Organic thermally stable materials for optoelectronics devices - A
  linear spectroscopy study

abstract:
  Thermally stable polymers have attracted a lot of interest due to their
potential use as the active component in electronic, optical and optoelectronic
applications, such as light-emitting diodes, light emitting electrochemical
cells, photodiodes, photovoltaic cells, field effect transistors, optocouplers
and optically pumped lasers in solution and solid state.We report results of
investigations into the use of thermal treatment of poly(p-phenylene vinylene)
(PPV) films grown on a variety of substrates (quartz and glass). Film
thickness, morphology and structural properties were investigated by a range of
techniques in particular: atomic force microscope - AFM, DEKTAK method,
Ellipsometry and UV-VIS spectroscopy.


title:
Elativistic treatment in}$D$ - Dimensions to a spin-zero particle with
  noncentral equal scalar and vector ring-shaped Kratzer potential

abstract:
  The Klein-Gordon equation in D-dimensions for a recently proposed Kratzer
potential plus ring-shaped potential is solved analytically by means of the
conventional Nikiforov-Uvarov method. The exact energy bound-states and the
corresponding wave functions of the Klein-Gordon are obtained in the presence
of the noncentral equal scalar and vector potentials. The results obtained in
this work are more general and can be reduced to the standard forms in
three-dimensions given by other works.


title:
On the potential of transit surveys in star clusters: Impact of
  correlated noise and radial velocity follow-up

abstract:
  We present an extension of the formalism recently proposed by Pepper & Gaudi
to evaluate the yield of transit surveys in homogeneous stellar systems,
incorporating the impact of correlated noise on transit time-scales on the
detectability of transits, and simultaneously incorporating the magnitude
limits imposed by the need for radial velocity follow-up of transit candidates.
New expressions are derived for the different contributions to the noise budget
on transit time-scales and the least-squares detection statistic for box-shaped
transits, and their behaviour as a function of stellar mass is re-examined.
Correlated noise that is constant with apparent stellar magnitude implies a
steep decrease in detection probability at the high mass end which, when
considered jointly with the radial velocity requirements, can severely limit
the potential of otherwise promising surveys in star clusters. However, we find
that small-aperture, wide field surveys may detect hot Neptunes whose radial
velocity signal can be measured with present-day instrumentation in very nearby
(<100 pc) clusters.


title: A non-perturbative proof of Bertrand's theorem

abstract:
  We discuss an alternative non-perturbative proof of Bertrand's theorem that
leads in a concise way directly to the two allowed fields: the newtonian and
the isotropic harmonic oscillator central fields.


title:
Neutron-Capture Elements in the Double-Enhanced Star HE 1305-0007: a New
  s- and r-Process Paradigm

abstract:
  The star HE 1305-0007 is a metal-poor double-enhanced star with metallicity
[Fe/H] $=-2.0$, which is just at the upper limit of the metallicity for the
observed double-enhanced stars. Using a parametric model, we find that almost
all s-elements were made in a single neutron exposure. This star should be a
member of a post-common-envelope binary. After the s-process material has
experienced only one neutron exposure in the nucleosynthesis region and is
dredged-up to its envelope, the AGB evolution is terminated by the onset of
common-envelope evolution. Based on the high radial-velocity of HE 1305-0007,
we speculate that the star could be a runaway star from a binary system, in
which the AIC event has occurred and produced the r-process elements.


title: Membrane in M5-branes Background

abstract:
  In this paper, we investigate the properties of a membrane in the M5-brane
background. Through solving the classical equations of motion of the membrane,
we can understand the classical dynamics of the membrane in this background.


title: 3D photospheric velocity field of a Supergranular cell

abstract:
  We investigate the plasma flow properties inside a Supergranular (SG) cell,
in particular its interaction with small scale magnetic field structures. The
SG cell has been identified using the magnetic network (CaII wing brightness)
as proxy, applying the Two-Level Structure Tracking (TST) to high spatial,
spectral and temporal resolution observations obtained by IBIS. The full 3D
velocity vector field for the SG has been reconstructed at two different
photospheric heights. In order to strengthen our findings, we also computed the
mean radial flow of the SG by means of cork tracing. We also studied the
behaviour of the horizontal and Line of Sight plasma flow cospatial with
cluster of bright CaII structures of magnetic origin to better understand the
interaction between photospheric convection and small scale magnetic features.
The SG cell we investigated seems to be organized with an almost radial flow
from its centre to the border. The large scale divergence structure is probably
created by a compact region of constant up-flow close to the cell centre. On
the edge of the SG, isolated regions of strong convergent flow are nearby or
cospatial with extended clusters of bright CaII wing features forming the knots
of the magnetic network.


title: Substructures in WINGS clusters

abstract:
  We search for and characterize substructures in the projected distribution of
galaxies observed in the wide field CCD images of the 77 nearby clusters of the
WIde-field Nearby Galaxy-cluster Survey (WINGS). This sample is complete in
X-ray flux in the redshift range 0.04<z<0.07. We search for substructures in
WINGS clusters with DEDICA, an adaptive-kernel procedure. We test the procedure
on Monte-Carlo simulations of the observed frames and determine the reliability
for the detected structures. DEDICA identifies at least one reliable structure
in the field of 55 clusters. 40 of these clusters have a total of 69
substructures at the same redshift of the cluster (redshift estimates of
substructures are from color-magnitude diagrams). The fraction of clusters with
subclusters (73%) is higher than in most studies. The presence of subclusters
affects the relative luminosities of the brightest cluster galaxies (BCGs).
Down to L ~ 10^11.2 L_Sun, our observed differential distribution of subcluster
luminosities is consistent with the theoretical prediction of the differential
mass function of substructures in cosmological simulations.


title:
Ising-like dynamics and frozen states in systems of ultrafine magnetic
  particles

abstract:
  We use Monte-Carlo simulations to study aging phenomena and the occurence of
spinglass phases in systems of single-domain ferromagnetic nanoparticles under
the combined influence of dipolar interaction and anisotropy energy, for
different combinations of positional and orientational disorder. We find that
the magnetic moments oriente themselves preferably parallel to their anisotropy
axes and changes of the total magnetization are solely achieved by 180 degree
flips of the magnetic moments, as in Ising systems. Since the dipolar
interaction favorizes the formation of antiparallel chain-like structures,
antiparallel chain-like patterns are frozen in at low temperatures, leading to
aging phenomena characteristic for spin-glasses. Contrary to the intuition,
these aging effects are more pronounced in ordered than in disordered
structures.


title: Counting characters in linear group actions

abstract:
  Let $G$ be a finite group and $V$ be a finite $G$--module. We present upper
bounds for the cardinalities of certain subsets of $\Irr(GV)$, such as the set
of those $\chi\in\Irr(GV)$ such that, for a fixed $v\in V$, the restriction of
$\chi$ to $<v>$ is not a multiple of the regular character of $<v>$. These
results might be useful in attacking the non--coprime $k(GV)$--problem.


title:
Continuous interfaces with disorder: Even strong pinning is too weak in
  2 dimensions

abstract:
  We consider statistical mechanics models of continuous height effective
interfaces in the presence of a delta-pinning at height zero. There is a
detailed mathematical understanding of the depinning transition in 2 dimensions
without disorder. Then the variance of the interface height w.r.t. the Gibbs
measure stays bounded uniformly in the volume for any positive pinning force
and diverges like the logarithm of the pinning force when it tends to zero.
  How does the presence of a quenched disorder term in the Hamiltonian modify
this transition? We show that an arbitarily weak random field term is enough to
beat an arbitrarily strong delta-pinning in 2 dimensions and will cause
delocalization. The proof is based on a rigorous lower bound for the overlap
between local magnetizations and random fields in finite volume. In 2
dimensions it implies growth faster than the volume which is a contradiction to
localization. We also derive a simple complementary inequality which shows that
in higher dimensions the fraction of pinned sites converges to one when the
pinning force tends to infinity.


title: On the KK-theory of strongly self-absorbing C*-algebras

abstract:
  Let $\Dh$ and $A$ be unital and separable $C^{*}$-algebras; let $\Dh$ be
strongly self-absorbing. It is known that any two unital $^*$-homomorphisms
from $\Dh$ to $A \otimes \Dh$ are approximately unitarily equivalent. We show
that, if $\Dh$ is also $K_{1}$-injective, they are even asymptotically
unitarily equivalent. This in particular implies that any unital endomorphism
of $\Dh$ is asymptotically inner. Moreover, the space of automorphisms of $\Dh$
is compactly-contractible (in the point-norm topology) in the sense that for
any compact Hausdorff space $X$, the set of homotopy classes $[X,\Aut(\Dh)]$
reduces to a point. The respective statement holds for the space of unital
endomorphisms of $\Dh$. As an application, we give a description of the
Kasparov group $KK(\Dh, A\ot \Dh)$ in terms of $^*$-homomorphisms and
asymptotic unitary equivalence. Along the way, we show that the Kasparov group
$KK(\Dh, A\ot \Dh)$ is isomorphic to $K_0(A\ot \Dh)$.


title: Effective interactions from q-deformed inspired transformations

abstract:
  From the mass term for the transformed quark fields, we obtain effective
contact interactions of the NJL type. The parameters of the model that maps a
system of non-interacting transformed fields into quarks interacting via NJL
contact terms are discussed.


title: Magnetospectroscopy of epitaxial few-layer graphene

abstract:
  The inter-Landau level transitions observed in far-infrared transmission
experiments on few-layer graphene samples show a behaviour characteristic of
the linear dispersion expected in graphene. This behaviour persists in
relatively thick samples, and is qualitatively different from that of thin
samples of bulk graphite.


title: Dust Formation and Survival in Supernova Ejecta

abstract:
  The presence of dust at high redshift requires efficient condensation of
grains in SN ejecta, in accordance with current theoretical models. Yet,
observations of the few well studied SNe and SN remnants imply condensation
efficiencies which are about two orders of magnitude smaller. Motivated by this
tension, we have (i) revisited the model of Todini & Ferrara (2001) for dust
formation in the ejecta of core collapse SNe and (ii) followed, for the first
time, the evolution of newly condensed grains from the time of formation to
their survival - through the passage of the reverse shock - in the SN remnant.
We find that 0.1 - 0.6 M_sun of dust form in the ejecta of 12 - 40 M_sun
stellar progenitors. Depending on the density of the surrounding ISM, between
2-20% of the initial dust mass survives the passage of the reverse shock, on
time-scales of about 4-8 x 10^4 yr from the stellar explosion. Sputtering by
the hot gas induces a shift of the dust size distribution towards smaller
grains. The resulting dust extinction curve shows a good agreement with that
derived by observations of a reddened QSO at z =6.2. Stochastic heating of
small grains leads to a wide distribution of dust temperatures. This supports
the idea that large amounts (~ 0.1 M_sun) of cold dust (T ~ 40K) can be present
in SN remnants, without being in conflict with the observed IR emission.


title:
Preferential interaction coefficient for nucleic acids and other
  cylindrical poly-ions

abstract:
  The thermodynamics of nucleic acid processes is heavily affected by the
electric double-layer of micro-ions around the polyions. We focus here on the
Coulombic contribution to the salt-polyelectrolyte preferential interaction
(Donnan) coefficient and we report extremely accurate analytical expressions
valid in the range of low salt concentration (when polyion radius is smaller
than the Debye length). The analysis is performed at Poisson-Boltzmann level,
in cylindrical geometry, with emphasis on highly charged poly-ions (beyond
``counter-ion condensation''). The results hold for any electrolyte of the form
$z_-$:$z_+$. We also obtain a remarkably accurate expression for the electric
potential in the vicinity of the poly-ion.


title: A new approach to mutual information

abstract:
  A new expression as a certain asymptotic limit via "discrete micro-states" of
permutations is provided to the mutual information of both continuous and
discrete random variables.


title:
Analysis of the real estate market in Las Vegas: Bubble, seasonal
  patterns, and prediction of the CSW indexes

abstract:
  We analyze 27 house price indexes of Las Vegas from Jun. 1983 to Mar. 2005,
corresponding to 27 different zip codes. These analyses confirm the existence
of a real-estate bubble, defined as a price acceleration faster than
exponential, which is found however to be confined to a rather limited time
interval in the recent past from approximately 2003 to mid-2004 and has
progressively transformed into a more normal growth rate comparable to
pre-bubble levels in 2005. There has been no bubble till 2002 except for a
medium-sized surge in 1990. In addition, we have identified a strong yearly
periodicity which provides a good potential for fine-tuned prediction from
month to month. A monthly monitoring using a model that we have developed could
confirm, by testing the intra-year structure, if indeed the market has returned
to ``normal'' or if more turbulence is expected ahead. We predict the evolution
of the indexes one year ahead, which is validated with new data up to Sep.
2006. The present analysis demonstrates the existence of very significant
variations at the local scale, in the sense that the bubble in Las Vegas seems
to have preceded the more global USA bubble and has ended approximately two
years earlier (mid 2004 for Las Vegas compared with mid-2006 for the whole of
the USA).


title:
A Low Complexity Algorithm and Architecture for Systematic Encoding of
  Hermitian Codes

abstract:
  We present an algorithm for systematic encoding of Hermitian codes. For a
Hermitian code defined over GF(q^2), the proposed algorithm achieves a run time
complexity of O(q^2) and is suitable for VLSI implementation. The encoder
architecture uses as main blocks q varying-rate Reed-Solomon encoders and
achieves a space complexity of O(q^2) in terms of finite field multipliers and
memory elements.


title:
Quantum criticality and disorder in the antiferromagnetic critical point
  of NiS$_{2}$ pyrite

abstract:
  A quantum critical point (QCP) between the antiferromagnetic and the
paramagnetic phases was realized by applying a hydrostatic pressure of ~ 7 GPa
on single crystals of NiS_{2} pyrite with a low residual resistivity, rho_{0},
of 0.5 mu-Omega-cm. We found that the critical behavior of the resistivity,
rho, in this clean system contrasts sharply with those observed in its
disordered analogue, NiS_{2-x}Se_{x} solid-solution, demonstrating the
unexpectedly drastic effect of disorder on the quantum criticality. Over a
whole paramagnetic region investigated up to P = 9 GPa, a crossover
temperature, defined as the onset of T^{2} dependence of rho, an indication of
Fermi liquid, was suppressed to a substantially low temperature T sim 2 K and,
instead, a non Fermi liquid behavior of rho, T^{3/2}-dependence, robustly
showed up.


title: Spin coherence of holes in GaAs/AlGaAs quantum wells

abstract:
  The carrier spin coherence in a p-doped GaAs/(Al,Ga)As quantum well with a
diluted hole gas has been studied by picosecond pump-probe Kerr rotation with
an in-plane magnetic field. For resonant optical excitation of the positively
charged exciton the spin precession shows two types of oscillations. Fast
oscillating electron spin beats decay with the radiative lifetime of the
charged exciton of 50 ps. Long lived spin coherence of the holes with dephasing
times up to 650 ps. The spin dephasing time as well as the in-plane hole g
factor show strong temperature dependence, underlining the importance of hole
localization at cryogenic temperatures.


title:
Local-field effects in radiatively broadened magneto-dielectric media:
  negative refraction and absorption reduction

abstract:
  We give a microscopic derivation of the Clausius-Mossotti relations for a
homogeneous and isotropic magneto-dielectric medium consisting of radiatively
broadened atomic oscillators. To this end the diagram series of electromagnetic
propagators is calculated exactly for an infinite bi-cubic lattice of
dielectric and magnetic dipoles for a lattice constant small compared to the
resonance wavelength $\lambda$. Modifications of transition frequencies and
linewidth of the elementary oscillators are taken into account in a
selfconsistent way by a proper incorporation of the singular self-interaction
terms. We show that in radiatively broadened media sufficiently close to the
free-space resonance the real part of the index of refraction approaches the
value -2 in the limit of $\rho \lambda^3 \gg 1$, where $\rho$ is the number
density of scatterers. Since at the same time the imaginary part vanishes as
$1/\rho$ local field effects can have important consequences for realizing
low-loss negative index materials.


title: Search for a fourth generation b'-quark at LEP-II at sqrt{s}=196-209 GeV

abstract:
  A search for the pair production of fourth generation b'-quarks was performed
using data taken by the DELPHI detector at LEP-II. The analysed data were
collected at centre-of-mass energies ranging from 196 to 209 GeV, corresponding
to an integrated luminosity of 420 pb^{-1}. No evidence for a signal was found.
Upper limits on BR(b' -> bZ) and BR(b' -> cW) were obtained for b' masses
ranging from 96 to 103 GeV/c^2. These limits, together with the theoretical
branching ratios predicted by a sequential four generations model, were used to
constrain the value of R_{CKM}=|V_{cb'}/V_{tb'}V_{tb}|, where V_{cb'}, V_{tb'}
and V_{tb} are elements of the extended CKM matrix.


title: About curvature, conformal metrics and warped products

abstract:
  We consider the curvature of a family of warped products of two
pseduo-Riemannian manifolds $(B,g_B)$ and $(F,g_F)$ furnished with metrics of
the form $c^{2}g_B \oplus w^2 g_F$ and, in particular, of the type $w^{2
\mu}g_B \oplus w^2 g_F$, where $c, w \colon B \to (0,\infty)$ are smooth
functions and $\mu$ is a real parameter. We obtain suitable expressions for the
Ricci tensor and scalar curvature of such products that allow us to establish
results about the existence of Einstein or constant scalar curvature structures
in these categories. If $(B,g_B)$ is Riemannian, the latter question involves
nonlinear elliptic partial differential equations with concave-convex
nonlinearities and singular partial differential equations of the
Lichnerowicz-York type among others.

categories: math.DG gr-qc hep-th math-ph math.AP math.MP


title: The local structure of conformally symmetric manifolds

abstract:
  This is a final step in a local classification of pseudo-Riemannian manifolds
with parallel Weyl tensor that are not conformally flat or locally symmetric.


title:
Investigation of Colour Reconnection in WW Events with the DELPHI
  detector at LEP-2

abstract:
  In the reaction e+e- -> WW -> (q_1 qbar_2)(q_3 qbar_4) the usual
hadronization models treat the colour singlets q_1 qbar_2 and q_3 qbar_4 coming
from two W bosons independently. However, since the final state partons may
coexist in space and time, cross-talk between the two evolving hadronic systems
may be possible during fragmentation through soft gluon exchange. This effect
is known as Colour Reconnection. In this article the results of the
investigation of Colour Reconnection effects in fully hadronic decays of W
pairs in DELPHI at LEP are presented. Two complementary analyses were
performed, studying the particle flow between jets and W mass estimators, with
negligible correlation between them, and the results were combined and compared
to models. In the framework of the SK-I model, the value for its kappa
parameter most compatible with the data was found to be: kappa_{SK-I} =
2.2^{+2.5}_{-1.3} corresponding to the probability of reconnection P_{reco} to
be in the range 0.31 < P_{reco} < 0.68 at 68% confidence level with its best
value at 0.52.


title:
Evolutionary Neural Gas (ENG): A Model of Self Organizing Network from
  Input Categorization

abstract:
  Despite their claimed biological plausibility, most self organizing networks
have strict topological constraints and consequently they cannot take into
account a wide range of external stimuli. Furthermore their evolution is
conditioned by deterministic laws which often are not correlated with the
structural parameters and the global status of the network, as it should happen
in a real biological system. In nature the environmental inputs are noise
affected and fuzzy. Which thing sets the problem to investigate the possibility
of emergent behaviour in a not strictly constrained net and subjected to
different inputs. It is here presented a new model of Evolutionary Neural Gas
(ENG) with any topological constraints, trained by probabilistic laws depending
on the local distortion errors and the network dimension. The network is
considered as a population of nodes that coexist in an ecosystem sharing local
and global resources. Those particular features allow the network to quickly
adapt to the environment, according to its dimensions. The ENG model analysis
shows that the net evolves as a scale-free graph, and justifies in a deeply
physical sense- the term gas here used.


title: X-ray Dichroism and the Pseudogap Phase of Cuprates

abstract:
  A recent polarized x-ray absorption experiment on the high temperature
cuprate superconductor Bi2Sr2CaCu2O8 indicates the presence of broken parity
symmetry below the temperature, T*, where a pseudogap appears in photoemission.
We critically analyze the x-ray data, and conclude that a parity-breaking
signal of the kind suggested is unlikely based on the crystal structures
reported in the literature. Possible other origins of the observed dichroism
signal are discussed. We propose x-ray scattering experiments that can be done
in order to determine whether such alternative interpretations are valid or
not.


title: Solvability of linear equations within weak mixing sets

abstract:
  We introduce a new class of "random" subsets of natural numbers, WM sets.
This class contains normal sets (sets whose characteristic function is a normal
binary sequence). We establish necessary and sufficient conditions for
solvability of systems of linear equations within every WM set and within every
normal set. We also show that partition-regular system of linear equations with
integer coefficients is solvable in any WM set.


title:
D-\bar D mixing and rare D decays in the Littlest Higgs model with
  non-unitarity matrix

abstract:
  We study the $D-\bar D$ mixing and rare D decays in the Littlest Higgs model.
As the new weak singlet quark with the electric charge of 2/3 is introduced to
cancel the quadratic divergence induced by the top-quark, the standard unitary
$3\times 3$ Cabibbo-Kobayashi-Maskawa matrix is extended to a non-unitary
$4\times 3$ matrix in the quark charged currents and Z-mediated flavor changing
neutral currents are generated at tree level. In this model, we show that the
$D-\bar D$ mixing parameter can be as large as the current experimental value
and the decay branching ratio (BR) of $D\to X_u \ga$ is small but its direct CP
asymmetry could be $O(10%)$. In addition, we find that the BRs of $D\to X_u
\ell^{+} \ell^{-}$, $D\to X_u\nu \bar \nu$ and $D\to \mu^{+} \mu^{-}$ could be
enhanced to be $O(10^{-9})$, $O(10^{-8})$ and $O(10^{-9})$, respectively.


title: Alternative Large Nc Schemes and Chiral Dynamics

abstract:
  We compare the dependences on the number of colors of the leading pion pion
scattering amplitudes using the single index quark field and two index quark
fields. These are seen to have different relationships to the scattering
amplitudes suggested by chiral dynamics which can explain the long puzzling
pion pion s wave scattering up to about 1 GeV. This may be interesting for
getting a better understanding of the large Nc approach as well as for
application to recently proposed technicolor models.


title:
The height dependence of temperature - velocity correlation in the solar
  photosphere

abstract:
  We derive correlation coefficients between temperature and line-of-sight
velocity as a function of optical depth throughout the solar photosphere for
the non-magnetic photosphere and a small area of enhanced magnetic activity.
The maximum anticorrelation of about -0.6 between temperature and line-of-sight
velocity in the non-magnetic photosphere occurs at log tau5 = -0.4. The
magnetic field is another decorrelating factor along with 5-min oscillations
and seeing.


title:
Magnetism in the high-Tc analogue Cs2AgF4 studied with muon-spin
  relaxation

abstract:
  We present the results of a muon-spin relaxation study of the high-Tc
analogue material Cs2AgF4. We find unambiguous evidence for magnetic order,
intrinsic to the material, below T_C=13.95(3) K. The ratio of inter- to
intraplane coupling is estimated to be |J'/J|=1.9 x 10^-2, while fits of the
temperature dependence of the order parameter reveal a critical exponent
beta=0.292(3), implying an intermediate character between pure two- and three-
dimensional magnetism in the critical regime. Above T_C we observe a signal
characteristic of dipolar interactions due to linear F-mu-F bonds, allowing the
muon stopping sites in this compound to be characterized.


title:
Reconciling the X(3872) with the near-threshold enhancement in the
  D^0\bar{D}^{*0} final state

abstract:
  We investigate the enhancement in the D^0\bar{D}^0\pi^0 final state with the
mass M=3875.2\pm 0.7^{+0.3}_{-1.6}\pm 0.8 MeV found recently by the Belle
Collaboration in the B\to K D^0\bar{D}^0\pi^0 decay and test the possibility
that this is yet another manifestation of the well-established resonance
X(3872). We perform a combined Flatte analysis of the data for the
D^0\bar{D}^0\pi^0 mode, and for the \pi^+\pi^- J/\psi mode of the X(3872). Only
if the X(3872) is a virtual state in the D^0\bar{D}^{*0} channel, the data on
the new enhancement comply with those on the X(3872). In our fits, the mass
distribution in the D^0\bar{D}^{*0} mode exhibits a peak at 2-3 MeV above the
D^0\bar{D}^{*0} threshold, with a distinctive non-Breit-Wigner shape.


title:
Three-dimensional effects in "atom diodes": atom-optical devices for
  one-way motion

abstract:
  The ``atom diode'' is a laser device that lets the ground state atom pass in
one direction but not in the opposite direction. We examine three-dimensional
effects of that device for arbitrary atomic incidence angles on flat laser
sheets and set breakdown limiting angles and velocities. It is found that a
correct diodic behavior independent of the incident angle can be obtained with
blue detuned lasers.


title:
Plasmon Amplification through Stimulated Emission at Terahertz
  Frequencies in Graphene

abstract:
  We show that plasmons in two-dimensional graphene can have net gain at
terahertz frequencies. The coupling of the plasmons to interband electron-hole
transitions in population inverted graphene layers can lead to plasmon
amplification through the process of stimulated emission. We calculate plasmon
gain for different electron-hole densities and temperatures and show that the
gain values can exceed $10^{4}$ cm$^{-1}$ in the 1-10 terahertz frequency
range, for electron-hole densities in the $10^{9}$-$10^{11}$ cm$^{-2}$ range,
even when plasmon energy loss due to intraband scattering is considered.
Plasmons are found to exhibit net gain for intraband scattering times shorter
than 100 fs. Such high gain values could allow extremely compact terahertz
amplifiers and oscillators that have dimensions in the 1-10 $\mu$m range.


title: On the homology of two-dimensional elimination

abstract:
  We study birational maps with empty base locus defined by almost complete
intersection ideals. Birationality is shown to be expressed by the equality of
two Chern numbers. We provide a relatively effective method of their
calculation in terms of certain Hilbert coefficients. In dimension two the
structure of the irreducible ideals leads naturally to the calculation of
Sylvester determinants via a computer-assisted method. For degree at most 5 we
produce the full set of defining equations of the base ideal. The results
answer affirmatively some questions raised by D. Cox.


title:
The effectiveness of quantum operations for eavesdropping on sealed
  messages

abstract:
  A quantum protocol is described which enables a user to send sealed messages
and that allows for the detection of active eavesdroppers. We examine a class
of eavesdropping strategies, those that make use of quantum operations, and we
determine the information gain versus disturbance caused by these strategies.
We demonstrate this tradeoff with an example and we compare this protocol to
quantum key distribution, quantum direct communication, and quantum seal
protocols.


title: Shocks in nonlocal media

abstract:
  We investigate the formation of collisionless shocks along the spatial
profile of a gaussian laser beam propagating in nonlocal nonlinear media. For
defocusing nonlinearity the shock survives the smoothing effect of the nonlocal
response, though its dynamics is qualitatively affected by the latter, whereas
for focusing nonlinearity it dominates over filamentation. The patterns
observed in a thermal defocusing medium are interpreted in the framework of our
theory.

categories: physics.optics cond-mat.soft nlin.PS physics.flu-dyn


title: Modeling the field of laser welding melt pool by RBFNN

abstract:
  Efficient control of a laser welding process requires the reliable prediction
of process behavior. A statistical method of field modeling, based on
normalized RBFNN, can be successfully used to predict the spatiotemporal
dynamics of surface optical activity in the laser welding process. In this
article we demonstrate how to optimize RBFNN to maximize prediction quality.
Special attention is paid to the structure of sample vectors, which represent
the bridge between the field distributions in the past and future.


title:
Solving The High Energy Evolution Equation Including Running Coupling
  Corrections

abstract:
  We study the solution of the nonlinear BK evolution equation with the
recently calculated running coupling corrections [hep-ph/0609105,
hep-ph/0609090]. Performing a numerical solution we confirm the earlier result
of [hep-ph/0408216] that the high energy evolution with the running coupling
leads to a universal scaling behavior for the dipole scattering amplitude. The
running coupling corrections calculated recently significantly change the shape
of the scaling function as compared to the fixed coupling case leading to a
considerable increase in the anomalous dimension and to a slow-down of the
evolution with rapidity. The difference between the two recent calculations is
due to an extra contribution to the evolution kernel, referred to as the
subtraction term, which arises when running coupling corrections are included.
These subtraction terms were neglected in both recent calculations. We evaluate
numerically the subtraction terms for both calculations, and demonstrate that
when the subtraction terms are added back to the evolution kernels obtained in
the two works the resulting dipole amplitudes agree with each other! We then
use the complete running coupling kernel including the subtraction term to find
the numerical solution of the resulting full non-linear evolution equation with
the running coupling corrections. Again the scaling regime is recovered at very
large rapidity.


title: Anomalous c-axis transport in layered metals

abstract:
  Transport in metals with strongly anisotropic single-particle spectrum is
studied. Coherent band transport in all directions, described by the standard
Boltzmann equation, is shown to withstand both elastic and inelastic scattering
as long as $E_F\tau\gg 1$. A model of phonon-assisted tunneling via resonant
states located in between the layers is suggested to explain a non-monotonic
temperature dependence of the c-axis resistivity observed in experiments.


title: Proper holomorphic mappings of the spectral unit ball

abstract:
  We prove an Alexander type theorem for the spectral unit ball $\Omega_n$
showing that there are no non-trivial proper holomorphic mappings in
$\Omega_n$, $n\geq 2$.


title: Parsimony via concensus

abstract:
  The parsimony score of a character on a tree equals the number of state
changes required to fit that character onto the tree. We show that for
unordered, reversible characters this score equals the number of tree
rearrangements required to fit the tree onto the character. We discuss
implications of this connection for the debate over the use of consensus trees
or total evidence, and show how it provides a link between incongruence of
characters and recombination.


title:
Millimeter imaging of HD 163296: probing the disk structure and
  kinematics

abstract:
  We present new multi-wavelength millimeter interferometric observations of
the Herbig Ae star HD 163296 obtained with the IRAM/PBI, SMA and VLA arrays
both in continuum and in the 12CO, 13CO and C18O emission lines. Gas and dust
properties have been obtained comparing the observations with self-consistent
disk models for the dust and CO emission. The circumstellar disk is resolved
both in the continuum and in CO. We find strong evidence that the circumstellar
material is in Keplerian rotation around a central star of 2.6 Msun. The disk
inclination with respect to the line of sight is 46+-4 deg with a position
angle of 128+-4 deg. The slope of the dust opacity measured between 0.87 and 7
mm (beta=1) confirms the presence of mm/cm-size grains in the disk midplane.
The dust continuum emission is asymmetric and confined inside a radius of 200
AU while the CO emission extends up to 540 AU. The comparison between dust and
CO temperature indicates that CO is present only in the disk interior. Finally,
we obtain an increasing depletion of CO isotopomers from 12CO to 13CO and C18O.
We argue that these results support the idea that the disk of HD 163296 is
strongly evolved. In particular, we suggest that there is a strong depletion of
dust relative to gas outside 200 AU; this may be due to the inward migration of
large bodies that form in the outer disk or to clearing of a large gap in the
dust distribution by a low mass companion.


title:
Spectropolarimetric observations of the Ca II 8498 A and 8542 A lines in
  the quiet Sun

abstract:
  The Ca II infrared triplet is one of the few magnetically sensitive
chromospheric lines available for ground-based observations. We present
spectropolarimetric observations of the 8498 A and 8542 A lines in a quiet Sun
region near a decaying active region and compare the results with a simulation
of the lines in a high plasma-beta regime. Cluster analysis of Stokes V profile
pairs shows that the two lines, despite arguably being formed fairly close,
often do not have similar shapes. In the network, the local magnetic topology
is more important in determining the shapes of the Stokes V profiles than the
phase of the wave, contrary to what our simulations show. We also find that
Stokes V asymmetries are very common in the network, and the histograms of the
observed amplitude and area asymmetries differ significantly from the
simulation. Both the network and internetwork show oscillatory behavior in the
Ca II lines. It is stronger in the network, where shocking waves, similar to
those in the high-beta simulation, are seen and large self-reversals in the
intensity profiles are common.


title:
Number of moduli of irreducible families of plane curves with nodes and
  cusps

abstract:
  Consider the family S of irreducible plane curves of degree n with d nodes
and k cusps as singularities. Let W be an irreducible component of S. We
consider the natural rational map from W to the moduli space of curves of genus
g=(n-1)(n-2)/2-d-k. We define the "number of moduli of W" as the dimension of
the image of W with respect to this map. If W has the expected dimension equal
to 3n+g-1-k, then the number of moduli of W is at most equal to the min(3g-3,
3g-3+\rho-k), dove \rho is the Brill-Neother number of the linear series of
degree n and dimension 2 on a smooth curve of genus g. We say that W has the
expected number of moduli if the equality holds. In this paper we construct
examples of families of irreducible plane curves with nodes and cusps as
singularities having expected number of moduli and with non-positive
Brill-Noether number.


title:
Search for Heavy Neutral MSSM Higgs Bosons with CMS: Reach and
  Higgs-Mass Precision

abstract:
  The search for MSSM Higgs bosons will be an important goal at the LHC. We
analyze the search reach of the CMS experiment for the heavy neutral MSSM Higgs
bosons with an integrated luminosity of 30 or 60 fb^-1. This is done by
combining the latest results for the CMS experimental sensitivities based on
full simulation studies with state-of-the-art theoretical predictions of MSSM
Higgs-boson properties. The results are interpreted in MSSM benchmark scenarios
in terms of the parameters tan_beta and the Higgs-boson mass scale, M_A. We
study the dependence of the 5 sigma discovery contours in the M_A-tan_beta
plane on variations of the other supersymmetric parameters. The largest effects
arise from a change in the higgsino mass parameter mu, which enters both via
higher-order radiative corrections and via the kinematics of Higgs decays into
supersymmetric particles. While the variation of $\mu$ can shift the
prospective discovery reach (and correspondingly the ``LHC wedge'' region) by
about Delta tan_beta = 10, we find that the discovery reach is rather stable
with respect to the impact of other supersymmetric parameters. Within the
discovery region we analyze the accuracy with which the masses of the heavy
neutral Higgs bosons can be determined. We find that an accuracy of 1-4% should
be achievable, which could make it possible in favourable regions of the MSSM
parameter space to experimentally resolve the signals of the two heavy MSSM
Higgs bosons at the LHC.


title: White dwarf masses derived from planetary nebulae modelling

abstract:
  We compare the mass distribution of central stars of planetary nebulae (CSPN)
with those of their progeny, white dwarfs (WD). We use a dynamical method to
measure masses with an uncertainty of 0.02 M$_\odot$. The CSPN mass
distribution is sharply peaked at $0.61 \rm M_\odot$. The WD distribution peaks
at lower masses ($0.58 \rm M_\odot$) and shows a much broader range of masses.
Some of the difference can be explained if the early post-AGB evolution is
faster than predicted by the Bl\"ocker tracks. Between 30 and 50 per cent of WD
may avoid the PN phase because of too low mass. However, the discrepancy cannot
be fully resolved and WD mass distributions may have been broadened by
observational or model uncertainties.


title: Uniqueness theorems for Cauchy integrals

abstract:
  If $\mu$ is a finite complex measure in the complex plane $\C$ we denote by
$C^\mu$ its Cauchy integral defined in the sense of principal value. The
measure $\mu$ is called reflectionless if it is continuous (has no atoms) and
$C^\mu=0$ at $\mu$-almost every point. We show that if $\mu$ is reflectionless
and its Cauchy maximal function $C^\mu_*$ is summable with respect to $|\mu|$
then $\mu$ is trivial. An example of a reflectionless measure whose maximal
function belongs to the "weak" $L^1$ is also constructed, proving that the
above result is sharp in its scale. We also give a partial geometric
description of the set of reflectionless measures on the line and discuss
connections of our results with the notion of sets of finite perimeter in the
sense of De Giorgi.


title: On the number of moduli of plane sextics with six cusps

abstract:
  Let S be the variety of irreducible sextics with six cusps as singularities.
Let W be one of irreducible components of W. Denoting by M_4 the space of
moduli of smooth curves of genus 4, the moduli map of W is the rational map
from W to M_4 sending the general point of W, corresponding to a plane curve D,
to the point of M_4 parametrizing the normalization curve of D. The number of
moduli of W is, by definition the dimension of the image of W with respect to
the moduli map. We know that this number is at most equal to seven. In this
paper we prove that both irreducible components of S have number of moduli
exactly equal to seven.


title: Algorithm for anisotropic diffusion in hydrogen-bonded networks

abstract:
  In this paper I describe a specialized algorithm for anisotropic diffusion
determined by a field of transition rates. The algorithm can be used to
describe some interesting forms of diffusion that occur in the study of proton
motion in a network of hydrogen bonds. The algorithm produces data that require
a nonstandard method of spectral analysis which is also developed here.
Finally, I apply the algorithm to a simple specific example.


title:
Temporal Evolution of Step-Edge Fluctuations Under Electromigration
  Conditions

abstract:
  The temporal evolution of step-edge fluctuations under electromigration
conditions is analysed using a continuum Langevin model. If the
electromigration driving force acts in the step up/down direction, and
step-edge diffusion is the dominant mass-transport mechanism, we find that
significant deviations from the usual $t^{1/4}$ scaling of the terrace-width
correlation function occurs for a critical time $\tau$ which is dependent upon
the three energy scales in the problem: $k_{B}T$, the step stiffness, $\gamma$,
and the bias associated with adatom hopping under the influence of an
electromigration force, $\pm \Delta U$. For ($t < \tau$), the correlation
function evolves as a superposition of $t^{1/4}$ and $t^{3/4}$ power laws. For
$t \ge \tau$ a closed form expression can be derived. This behavior is
confirmed by a Monte-Carlo simulation using a discrete model of the step
dynamics. It is proposed that the magnitude of the electromigration force
acting upon an atom at a step-edge can by estimated by a careful analysis of
the statistical properties of step-edge fluctuations on the appropriate
time-scale.


title: Renormgroup origin and analysis of Split Higgsino scenario

abstract:
  We present a renormalization group motivation of scale hierarchies in SUSY
SU(5) model. The Split Higgsino scanrio with a high scale of the SUSY breaking
is considered in detail. Its manifestations in experiments are discussed.


title:
Probing dark energy with steerable wavelets through correlation of WMAP
  and NVSS local morphological measures

abstract:
  Using local morphological measures on the sphere defined through a steerable
wavelet analysis, we examine the three-year WMAP and the NVSS data for
correlation induced by the integrated Sachs-Wolfe (ISW) effect. The steerable
wavelet constructed from the second derivative of a Gaussian allows one to
define three local morphological measures, namely the signed-intensity,
orientation and elongation of local features. Detections of correlation between
the WMAP and NVSS data are made with each of these morphological measures. The
most significant detection is obtained in the correlation of the
signed-intensity of local features at a significance of 99.9%. By inspecting
signed-intensity sky maps, it is possible for the first time to see the
correlation between the WMAP and NVSS data by eye. Foreground contamination and
instrumental systematics in the WMAP data are ruled out as the source of all
significant detections of correlation. Our results provide new insight on the
ISW effect by probing the morphological nature of the correlation induced
between the cosmic microwave background and large scale structure of the
Universe. Given the current constraints on the flatness of the Universe, our
detection of the ISW effect again provides direct and independent evidence for
dark energy. Moreover, this new morphological analysis may be used in future to
help us to better understand the nature of dark energy.


title:
Electromagnetic structure and weak decay of meson K in a light-front
  QCD-inspired

abstract:
  The kaon electromagnetic (e.m.) form factor is reviewed considering a
light-front constituent quark model. In this approach, it is discussed the
relevance of the quark-antiquark pair terms for the full covariance of the e.m.
current. It is also verified, by considering a QCD dynamical model, that a good
agreement with experimental data can be obtained for the kaon weak decay
constant once a probability of about 80% of the valence component is taken into
account.


title:
Black hole puncture initial data with realistic gravitational wave
  content

abstract:
  We present improved post-Newtonian-inspired initial data for non-spinning
black-hole binaries, suitable for numerical evolution with punctures. We
revisit the work of Tichy et al. [W. Tichy, B. Bruegmann, M. Campanelli, and P.
Diener, Phys. Rev. D 67, 064008 (2003)], explicitly calculating the remaining
integral terms. These terms improve accuracy in the far zone and, for the first
time, include realistic gravitational waves in the initial data. We investigate
the behavior of these data both at the center of mass and in the far zone,
demonstrating agreement of the transverse-traceless parts of the new metric
with quadrupole-approximation waveforms. These data can be used for numerical
evolutions, enabling a direct connection between the merger waveforms and the
post-Newtonian inspiral waveforms.


title: Measurement of the Decay Constant $f_D{_S^+}$ using $D_S^+ --> ell^+ nu

abstract:
  We measure the decay constant fDs using the Ds -> l+ nu channel, where the l+
designates either a mu+ or a tau+, when the tau+ -> pi+ nu. Using both
measurements we find fDs = 274 +-13 +- 7 MeV. Combining with our previous
determination of fD+, we compute the ratio fDs/fD+ = 1.23 +- 0.11 +- 0.04. We
compare with theoretical estimates.


title:
The $e^+ e^-\to K^+ K^- \pi^+\pi^-$, $K^+ K^- \pi^0\pi^0$ and $K^+ K^-
  K^+ K^-$ Cross Sections Measured with Initial-State Radiation

abstract:
  We study the processes $e^+ e^-\to K^+ K^- \pi^+\pi^-\gamma$,
$K^+K^-\pi^0\pi^0\gamma$ and $K^+ K^- K^+ K^-\gamma$, where the photon is
radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed
events, respectively, are selected from 232 \invfb of \babar data. The
invariant mass of the hadronic final state defines the effective \epem
center-of-mass energy, so that the $K^+ K^- \pi^+\pi^-\gamma$ data can be
compared with direct measurements of the $e^+ e^-\to K^+K^- \pipi$ reaction; no
direct measurements exist for the $e^+ e^-\to K^+ K^- \pi^0\pi^0$ or $\epem\to
K^+ K^- K^+ K^-$ reactions. Studying the structure of these events, we find
contributions from a number of intermediate states, and we extract their cross
sections where possible. In particular, we isolate the contribution from $e^+
e^-\to\phi(1020) f_{0}(980)$ and study its structure near threshold. In the
charmonium region, we observe the $J/\psi$ in all three final states and
several intermediate states, as well as the $\psi(2S)$ in some modes, and
measure the corresponding branching fractions. We see no signal for the Y(4260)
and obtain an upper limit of
$\BR_{Y(4260)\to\phi\pi^+\pi^-}\cdot\Gamma^{Y}_{ee}<0.4 \ev$ at 90% C.L.


title:
Orthogonality criterion for banishing hydrino states from standard
  quantum mechanics

abstract:
  Orthogonality criterion is used to shown in a very simple and general way
that anomalous bound-state solutions for the Coulomb potential (hydrino states)
do not exist as bona fide solutions of the Schr\"{o}dinger, Klein-Gordon and
Dirac equations.


title: Detecting and Characterizing Planetary Systems with Transit Timing

abstract:
  In the coming decades, research in extrasolar planets aims to advance two
goals: 1) detecting and characterizing low-mass planets increasingly similar to
the Earth, and 2) improving our understanding of planet formation. We present a
new planet detection method that is capable of making large advances towards
both of these objectives and describe a modest network of telescopes that is
able to make the requisite observations. In a system where a known planet
transits its host star, a second planet in that system will cause the time
between transits to vary. These transit timing variations can be used to infer
the orbital elements and mass of the perturbing planet even if it has a mass
that is smaller than the mass of the Earth. This detection technique
complements other techniques because it is most sensitive in mean-motion
resonances where, due to degeneracies, other techniques have reduced
sensitivity. Small ground-based observatories have already exceeded the
photometric precision necessary to detect sub-Earth mass planets. However, TTV
planet searches are currently limited by the relatively small number of
high-precision transit data and insufficient observing time on existing
telescopes. These issues will be compounded as the number of known transiting
planets suitable for TTV study will increase substantially in the near future.
A relatively modest investment in a ground-based network of small ($\sim 0.5
{\rm m}$ telescopes could provide the needed coverage and so dramatically
increase the effectiveness of transit timing observations.


title: d-wave superconductivity from electron-phonon interactions

abstract:
  I examine electron-phonon mediated superconductivity in the intermediate
coupling and phonon frequency regime of the quasi-2D Holstein model. I use an
extended Migdal-Eliashberg theory which includes vertex corrections and spatial
fluctuations. I find a d-wave superconducting state that is unique close to
half-filling. The order parameter undergoes a transition to s-wave
superconductivity on increasing filling. I explain how the inclusion of both
vertex corrections and spatial fluctuations is essential for the prediction of
a d-wave order parameter. I then discuss the effects of a large Coulomb
pseudopotential on the superconductivity (such as is found in contemporary
superconducting materials like the cuprates), which results in the destruction
of the s-wave states, while leaving the d-wave states unmodified.


title:
A Finite Element framework for computation of protein normal modes and
  mechanical response

abstract:
  A coarse-grained computational procedure based on the Finite Element Method
is proposed to calculate the normal modes and mechanical response of proteins
and their supramolecular assemblies. Motivated by the elastic network model,
proteins are modeled as homogeneous isotropic elastic solids with volume
defined by their solvent-excluded surface. The discretized Finite Element
representation is obtained using a surface simplification algorithm that
facilitates the generation of models of arbitrary prescribed spatial
resolution. The procedure is applied to compute the normal modes of a mutant of
T4 phage lysozyme and of filamentous actin, as well as the critical Euler
buckling load of the latter when subject to axial compression. Results compare
favorably with all-atom normal mode analysis, the Rotation Translation Blocks
procedure, and experiment. The proposed methodology establishes a computational
framework for the calculation of protein mechanical response that facilitates
the incorporation of specific atomic-level interactions into the model,
including aqueous-electrolyte-mediated electrostatic effects. The procedure is
equally applicable to proteins with known atomic coordinates as it is to
electron density maps of proteins, protein complexes, and supramolecular
assemblies of unknown atomic structure.


title:
Reply to 'Comment on 'Heavy element production in inhomogeneous big bang
  nucleosynthesis''

abstract:
  This is a reply report to astro-ph/0604264. We studied heavy element
production in high baryon density region in early universe astro-ph/0507439.
However it is claimed in astro-ph/0604264 that small scale but high baryon
density region contradicts observations for the light element abundance or in
order not to contradict to observations high density region must be so small
that it cannot affect the present heavy element abundance.
  In this paper we study big bang nucleosynthesis in high baryon density region
and show that in certain parameter spaces it is possible to produce enough
amount of heavy element without contradiction to CMB and light element
observations.


title:
Sum-over-states vs quasiparticle pictures of coherent correlation
  spectroscopy of excitons in semiconductors; femtosecond analogues of
  multidimensional NMR

abstract:
  Two-dimensional correlation spectroscopy (2DCS) based on the nonlinear
optical response of excitons to sequences of ultrafast pulses, has the
potential to provide some unique insights into carrier dynamics in
semiconductors. The most prominent feature of 2DCS, cross peaks, can best be
understood using a sum-over-states picture involving the many-body eigenstates.
However, the optical response of semiconductors is usually calculated by
solving truncated equations of motion for dynamical variables, which result in
a quasiparticle picture. In this work we derive Green's function expressions
for the four wave mixing signals generated in various phase-matching directions
and use them to establish the connection between the two pictures. The formal
connection with Frenkel excitons (hard-core bosons) and vibrational excitons
(soft-core bosons) is pointed out.


title:
Are constant loop widths an artifact of the background and the spatial
  resolution?

abstract:
  We study the effect of the coronal background in the determination of the
diameter of EUV loops, and we analyze the suitability of the procedure followed
in a previous paper (L\'opez Fuentes, Klimchuk & D\'emoulin 2006) for
characterizing their expansion properties. For the analysis we create different
synthetic loops and we place them on real backgrounds from data obtained with
the Transition Region and Coronal Explorer (\textit{TRACE}). We apply to these
loops the same procedure followed in our previous works, and we compare the
results with real loop observations. We demonstrate that the procedure allows
us to distinguish constant width loops from loops that expand appreciably with
height, as predicted by simple force-free field models. This holds even for
loops near the resolution limit. The procedure can easily determine when loops
are below resolution limit and therefore not reliably measured. We find that
small-scale variations in the measured loop width are likely due to
imperfections in the background subtraction. The greatest errors occur in
especially narrow loops and in places where the background is especially bright
relative to the loop. We stress, however, that these effects do not impact the
ability to measure large-scale variations. The result that observed loops do
not expand systematically with height is robust.


title:
Polarizations of J/psi and psi(2S) Mesons Produced in ppbar Collisions
  at 1.96 TeV

abstract:
  We have measured the polarizations of $\jpsi$ and $\psiprime$ mesons as
functions of their transverse momentum $\pt$ when they are produced promptly in
the rapidity range $|y|<0.6$ with $\pt \geq 5 \pgev$. The analysis is performed
using a data sample with an integrated luminosity of about $800 \ipb$ collected
by the CDF II detector. For both vector mesons, we find that the polarizations
become increasingly longitudinal as $\pt$ increases from 5 to $30 \pgev$. These
results are compared to the predictions of nonrelativistic quantum
chromodynamics and other contemporary models. The effective polarizations of
$\jpsi$ and $\psiprime$ mesons from $B$-hadron decays are also reported.


title: A measure of the non-Gaussian character of a quantum state

abstract:
  We address the issue of quantifying the non-Gaussian character of a bosonic
quantum state and introduce a non-Gaussianity measure based on the
Hilbert-Schmidt distance between the state under examination and a reference
Gaussian state. We analyze in details the properties of the proposed measure
and exploit it to evaluate the non-Gaussianity of some relevant single- and
multi-mode quantum states. The evolution of non-Gaussianity is also analyzed
for quantum states undergoing the processes of Gaussification by loss and
de-Gaussification by photon-subtraction. The suggested measure is easily
computable for any state of a bosonic system and allows to define a
corresponding measure for the non-Gaussian character of a quantum operation.


title: Skew-Hadamard matrices of orders 188 and 388 exist

abstract:
  We construct several difference families on cyclic groups of orders 47 and
97, and use them to construct skew-Hadamard matrices of orders 188 and 388.
Such difference families and matrices are constructed here for the first time.
The matrices are constructed by using the Goethals-Seidel array.


title: Quantum engineering of photon states with entangled atomic ensembles

abstract:
  We propose and analyze a new method to produce single and entangled photons
which does not require cavities. It relies on the collective enhancement of
light emission as a consequence of the presence of entanglement in atomic
ensembles. Light emission is triggered by a laser pulse, and therefore our
scheme is deterministic. Furthermore, it allows one to produce a variety of
photonic entangled states by first preparing certain atomic states using simple
sequences of quantum gates. We analyze the feasibility of our scheme, and
particularize it to: ions in linear traps, atoms in optical lattices, and in
cells at room temperature.


title: Direct photons and dileptons via color dipoles

abstract:
  Drell-Yan dilepton pair production and inclusive direct photon production can
be described within a unified framework in the color dipole approach. The
inclusion of non-perturbative primordial transverse momenta and DGLAP evolution
is studied. We successfully describe data for dilepton spectra from 800-GeV pp
collisions, inclusive direct photon spectra for pp collisions at RHIC energies
$\sqrt{s}=200$ GeV, and for $p\bar{p}$ collisions at Tevatron energies
$\sqrt{s}=1.8$ TeV, in a formalism that is free from any extra parameters.


title: Mapping the Youngest Galaxies to Redshift One

abstract:
  We describe results of a narrow band search for ultra-strong emission line
galaxies (USELs) with EW(H beta) > 30 A. 542 candidate galaxies are found in a
half square degree survey using two ~100 Angstrom 8150 A and 9140 A filters
with Subaru/SuprimeCam. Followup spectroscopy for randomly selected objects in
the sample with KeckII/DEIMOS shows they consist of [OIII] 5007, [OII] 3727,
and H alpha selected strong-emission line galaxies at intermediate redshifts (z
< 1), and Ly alpha emitting galaxies at high-redshift (z >> 5). We determine
the H beta luminosity functions and the star formation density of the USELs,
which is 5-10% of the value found from ultraviolet continuum objects at z=0-1,
suggesting they correspond to a major epoch in galaxy formation at these
redshifts. Many USELs show the temperature-sensitive [OIII] 4363 auroral lines
and about a dozen have oxygen abundances characteristic of eXtremely Metal Poor
Galaxies (XMPGs). These XMPGs are the most distant known today. Our high yield
rate of XMPGs suggests this is a powerful method for finding such populations.
The lowest metallicity measured in our sample is 12+log(O/H) = 7.06
(6.78-7.44), close to the minimum metallicity found in local galaxies. The
luminosities, metallicities and star formation rates of USELs are consistent
with the strong emitters being start-up intermediate mass galaxies and suggest
that galaxies are still forming in relatively chemically pristine sites at z <
1.


title: On the HOMFLY and Tutte polynomials

abstract:
  A celebrated result of F. Jaeger states that the Tutte polynomial of a planar
graph is determined by the HOMFLY polynomial of an associated link. Here we are
interested in the converse of this result. We consider the question `to what
extent does the Tutte polynomial determine the HOMFLY polynomial of any knot?'
We show that the HOMFLY polynomial of a knot is determined by Tutte polynomials
of plane graphs associated to the knot.


title: Discovery of extreme asymmetry in the debris disk surrounding HD 15115

abstract:
  We report the first scattered light detection of a dusty debris disk
surrounding the F2V star HD 15115 using the Hubble Space Telescope in the
optical, and Keck adaptive optics in the near-infrared. The most remarkable
property of the HD 15115 disk relative to other debris disks is its extreme
length asymmetry. The east side of the disk is detected to ~315 AU radius,
whereas the west side of the disk has radius >550 AU. We find a blue optical to
near-infrared scattered light color relative to the star that indicates grain
scattering properties similar to the AU Mic debris disk. The existence of a
large debris disk surrounding HD 15115 adds further evidence for membership in
the Beta Pic moving group, which was previously argued based on kinematics
alone. Here we hypothesize that the extreme disk asymmetry is due to dynamical
perturbations from HIP 12545, an M star 0.5 degrees (0.38 pc) east of HD 15115
that shares a common proper motion vector, heliocentric distance, galactic
space velocity, and age.


title: The Mathematical Universe

abstract:
  I explore physics implications of the External Reality Hypothesis (ERH) that
there exists an external physical reality completely independent of us humans.
I argue that with a sufficiently broad definition of mathematics, it implies
the Mathematical Universe Hypothesis (MUH) that our physical world is an
abstract mathematical structure. I discuss various implications of the ERH and
MUH, ranging from standard physics topics like symmetries, irreducible
representations, units, free parameters, randomness and initial conditions to
broader issues like consciousness, parallel universes and Godel incompleteness.
I hypothesize that only computable and decidable (in Godel's sense) structures
exist, which alleviates the cosmological measure problem and help explain why
our physical laws appear so simple. I also comment on the intimate relation
between mathematical structures, computations, simulations and physical
systems.


title: Testing String Theory with CMB

abstract:
  Future detection/non-detection of tensor modes from inflation in CMB
observations presents a unique way to test certain features of string theory.
Current limit on the ratio of tensor to scalar perturbations, r=T/S, is r <
0.3, future detection may take place for r > 10^{-2}-10^{-3}. At present all
known string theory inflation models predict tensor modes well below the level
of detection. Therefore a possible experimental discovery of tensor modes may
present a challenge to string cosmology.
  The strongest bound on r in string inflation follows from the observation
that in most of the models based on the KKLT construction, the value of the
Hubble constant H during inflation must be smaller than the gravitino mass. For
the gravitino mass in the usual range, m_{3/2} < O(1) TeV, this leads to an
extremely strong bound r < 10^{-24}. A discovery of tensor perturbations with r
> 10^{-3} would imply that the gravitinos in this class of models are
superheavy, m_{3/2} > 10^{13} GeV. This would have important implications for
particle phenomenology based on string theory.


title: Behavioral response to strong aversive stimuli: A neurodynamical model

abstract:
  In this paper a theoretical model of functioning of a neural circuit during a
behavioral response has been proposed. A neural circuit can be thought of as a
directed multigraph whose each vertex is a neuron and each edge is a synapse.
It has been assumed in this paper that the behavior of such circuits is
manifested through the collective behavior of neurons belonging to that
circuit. Behavioral information of each neuron is contained in the coefficients
of the fast Fourier transform (FFT) over the output spike train. Those
coefficients form a vector in a multidimensional vector space. Behavioral
dynamics of a neuronal network in response to strong aversive stimuli has been
studied in a vector space in which a suitable pseudometric has been defined.
The neurodynamical model of network behavior has been formulated in terms of
existing memory, synaptic plasticity and feelings. The model has an analogy in
classical electrostatics, by which the notion of force and potential energy has
been introduced. Since the model takes input from each neuron in a network and
produces a behavior as the output, it would be extremely difficult or may even
be impossible to implement. But with the help of the model a possible
explanation for an hitherto unexplained neurological observation in human brain
has been offered. The model is compatible with a recent model of sequential
behavioral dynamics. The model is based on electrophysiology, but its relevance
to hemodynamics has been outlined.


title: Quivers with potentials and their representations I: Mutations

abstract:
  We study quivers with relations given by non-commutative analogs of Jacobian
ideals in the complete path algebra. This framework allows us to give a
representation-theoretic interpretation of quiver mutations at arbitrary
vertices. This gives a far-reaching generalization of
Bernstein-Gelfand-Ponomarev reflection functors. The motivations for this work
come from several sources: superpotentials in physics, Calabi-Yau algebras,
cluster algebras.


title: Coherent macroscopic quantum tunneling in boson-fermion mixtures

abstract:
  We show that the cold atom systems of simultaneously trapped Bose-Einstein
condensates (BEC's) and quantum degenerate fermionic atoms provide promising
laboratories for the study of macroscopic quantum tunneling. Our theoretical
studies reveal that the spatial extent of a small trapped BEC immersed in a
Fermi sea can tunnel and coherently oscillate between the values of the
separated and mixed configurations (the phases of the phase separation
transition of BEC-fermion systems). We evaluate the period, amplitude and
dissipation rate for $^{23}$Na and $^{40}$K-atoms and we discuss the
experimental prospects for observing this phenomenon.


title: Efficiency of thin film photocells

abstract:
  We propose a new concept for the design of high-efficiency photocells based
on ultra-thin (submicron) semiconductor films of controlled thickness. Using a
microscopic model of a thin dielectric layer interacting with incident
electromagnetic radiation we evaluate the efficiency of conversion of solar
radiation into the electric power. We determine the optimal range of parameters
which maximize the efficiency of such photovoltaic element.


title: Galactic Wind Signatures around High Redshift Galaxies

abstract:
  We carry out cosmological chemodynamical simulations with different strengths
of supernova (SN) feedback and study how galactic winds from star-forming
galaxies affect the features of hydrogen (HI) and metal (CIV and OVI)
absorption systems in the intergalactic medium at high redshift. We find that
the outflows tend to escape to low density regions, and hardly affect the dense
filaments visible in HI absorption. As a result, the strength of HI absorption
near galaxies is not reduced by galactic winds, but even slightly increases. We
also find that a lack of HI absorption for lines of sight (LOS) close to
galaxies, as found by Adelberger et al., can be created by hot gas around the
galaxies induced by accretion shock heating. In contrast to HI, metal
absorption systems are sensitive to the presence of winds. The models without
feedback can produce the strong CIV and OVI absorption lines in LOS within 50
kpc from galaxies, while strong SN feedback is capable of creating strong CIV
and OVI lines out to about twice that distance. We also analyze the mean
transmissivity of HI, CIV, and OVI within 1 h$^{-1}$ Mpc from star-forming
galaxies. The probability distribution of the transmissivity of HI is
independent of the strength of SN feedback, but strong feedback produces LOS
with lower transmissivity of metal lines. Additionally, strong feedback can
produce strong OVI lines even in cases where HI absorption is weak. We conclude
that OVI is probably the best tracer for galactic winds at high redshift.


title: `St\"uckelberg interferometry' with ultracold molecules

abstract:
  We report on the realization of a time-domain `St\"uckelberg interferometer',
which is based on the internal state structure of ultracold Feshbach molecules.
Two subsequent passages through a weak avoided crossing between two different
orbital angular momentum states in combination with a variable hold time lead
to high-contrast population oscillations. This allows for a precise
determination of the energy difference between the two molecular states. We
demonstrate a high degree of control over the interferometer dynamics. The
interferometric scheme provides new possibilities for precision measurements
with ultracold molecules.


title:
An integral field spectroscopic survey for high redshift damped
  Lyman-alpha galaxies

abstract:
  We search for galaxy counterparts to damped Lyman-alpha absorbers (DLAs) at
z>2 towards nine quasars, which have 14 DLAs and 8 sub-DLAs in their spectra.
We use integral field spectroscopy to search for Ly-alpha emission line objects
at the redshifts of the absorption systems. Besides recovering two previously
confirmed objects, we find six statistically significant candidate Ly-alpha
emission line objects. The candidates are identified as having wavelengths
close to the DLA line where the background quasar emission is absorbed. In
comparison with the six currently known Ly-alpha emitting DLA galaxies the
candidates have similar line fluxes and line widths, while velocity offsets
between the emission lines and systemic DLA redshifts are larger. The impact
parameters are larger than 10 kpc, and lower column density systems are found
at larger impact parameters. Assuming that a single gas cloud extends from the
QSO line of sight to the location of the candidate emission line, we find that
the average candidate DLA galaxy is surrounded by neutral gas with an
exponential scale length of ~5 kpc.


title: Exploring the Variable Sky with the Sloan Digital Sky Survey

abstract:
  We quantify the variability of faint unresolved optical sources using a
catalog based on multiple SDSS imaging observations. The catalog covers SDSS
Stripe 82, and contains 58 million photometric observations in the SDSS ugriz
system for 1.4 million unresolved sources. In each photometric bandpass we
compute various low-order lightcurve statistics and use them to select and
study variable sources. We find that 2% of unresolved optical sources brighter
than g=20.5 appear variable at the 0.05 mag level (rms) simultaneously in the g
and r bands. The majority (2/3) of these variable sources are low-redshift (<2)
quasars, although they represent only 2% of all sources in the adopted
flux-limited sample. We find that at least 90% of quasars are variable at the
0.03 mag level (rms) and confirm that variability is as good a method for
finding low-redshift quasars as is the UV excess color selection (at high
Galactic latitudes). We analyze the distribution of lightcurve skewness for
quasars and find that is centered on zero. We find that about 1/4 of the
variable stars are RR Lyrae stars, and that only 0.5% of stars from the main
stellar locus are variable at the 0.05 mag level. The distribution of
lightcurve skewness in the g-r vs. u-g color-color diagram on the main stellar
locus is found to be bimodal (with one mode consistent with Algol-like
behavior). Using over six hundred RR Lyrae stars, we demonstrate rich halo
substructure out to distances of 100 kpc. We extrapolate these results to
expected performance by the Large Synoptic Survey Telescope and estimate that
it will obtain well-sampled 2% accurate, multi-color lightcurves for ~2 million
low-redshift quasars, and will discover at least 50 million variable stars.


title:
Necessary optimality conditions for the calculus of variations on time
  scales

abstract:
  We study more general variational problems on time scales. Previous results
are generalized by proving necessary optimality conditions for (i) variational
problems involving delta derivatives of more than the first order, and (ii)
problems of the calculus of variations with delta-differential side conditions
(Lagrange problem of the calculus of variations on time scales).


title:
The Boundary Conditions of the Heliosphere: Photoionization Models
  Constrained by Interstellar and In Situ Data

abstract:
  The boundary conditions of the heliosphere are set by the ionization, density
and composition of inflowing interstellar matter. Constraining the properties
of the Local Interstellar Cloud (LIC) at the heliosphere requires radiative
transfer ionization models. We model the background interstellar radiation
field using observed stellar FUV and EUV emission and the diffuse soft X-ray
background. We also model the emission from the boundary between the LIC and
the hot Local Bubble (LB) plasma, assuming that the cloud is evaporating
because of thermal conduction. We create a grid of models covering a plausible
range of LIC and LB properties, and use the modeled radiation field as input to
radiative transfer/thermal equilibrium calculations using the Cloudy code. Data
from in situ observations of He^O, pickup ions and anomalous cosmic rays in the
heliosphere, and absorption line measurements towards epsilon CMa were used to
constrain the input parameters. A restricted range of assumed LIC HI column
densities and LB plasma temperatures produce models that match all the
observational constraints. The relative weakness of the constraints on N(HI)
and T_h contrast with the narrow limits predicted for the H^O and electron
density in the LIC at the Sun, n(H^0) = 0.19 - 0.20 cm^-3, and n(e) = 0.07 +/-
0.01 cm^-3. Derived abundances are mostly typical for low density gas, with
sub-solar Mg, Si and Fe, possibly subsolar O and N, and S about solar; however
C is supersolar. The interstellar gas at the Sun is warm, low density, and
partially ionized, with n(H) = 0.23 - 0.27 cm^-3, T = 6300 K, X(H^+) ~ 0.2, and
X(He^+) ~ 0.4. These results appear to be robust since acceptable models are
found for substantially different input radiation fields. Our results favor low
values for the reference solar abundances for the LIC composition.


title:
Collective excitations in a magnetically doped quantized Hall
  ferromagnet

abstract:
  A theory of collective states in a magnetically quantized two-dimensional
electron gas (2DEG) with half-filled Landau level (quantized Hall ferromagnet)
in the presence of magnetic 3d impurities is developed. The spectrum of bound
and delocalized spin-excitons as well as the renormalization of Zeeman
splitting of the impurity 3d levels due to the indirect exchange interaction
with the 2DEG are studied for the specific case of n-type GaAs doped with Mn
where the Lande` g-factors of impurity and 2DEG have opposite signs. If the
sign of the 2DEG g-factor is changed due to external influences, then impurity
related transitions to new ground state phases, presenting various spin-flip
and skyrmion-like textures, are possible. Conditions for existence of these
phases are discussed. PACS: 73.43.Lp, 73.21.Fg, 72.15.Rn


title: Long Gamma-Ray Burst Progenitors: Boundary Conditions and Binary Models

abstract:
  The observed association of Long Gamma-Ray Bursts (LGRBs) with peculiar Type
Ic supernovae gives support to Woosley`s collapsar/hypernova model, in which
the GRB is produced by the collapse of the rapidly rotating core of a massive
star to a black hole. The association of LGRBs with small star-forming galaxies
suggests low-metallicity to be a condition for a massive star to evolve to the
collapsar stage. Both completely-mixed single star models and binary star
models are possible. In binary models the progenitor of the GRB is a massive
helium star with a close companion. We find that tidal synchronization during
core-helium burning is reached on a short timescale (less than a few
millennia). However, the strong core-envelope coupling in the subsequent
evolutionary stages is likely to rule out helium stars with main-sequence
companions as progenitors of hypernovae/GRBs. On the other hand, helium stars
in close binaries with a neutron-star or black-hole companion can, despite the
strong core-envelope coupling in the post-helium burning phase, retain
sufficient core angular momentum to produce a hypernova/GRB.


title:
Multiscale model of electronic behavior and localization in stretched
  dry DNA

abstract:
  When the DNA double helix is subjected to external forces it can stretch
elastically to elongations reaching 100% of its natural length. These
distortions, imposed at the mesoscopic or macroscopic scales, have a dramatic
effect on electronic properties at the atomic scale and on electrical transport
along DNA. Accordingly, a multiscale approach is necessary to capture the
electronic behavior of the stretched DNA helix. To construct such a model, we
begin with accurate density-functional-theory calculations for electronic
states in DNA bases and base pairs in various relative configurations
encountered in the equilibrium and stretched forms. These results are
complemented by semi-empirical quantum mechanical calculations for the states
of a small size [18 base pair poly(CG)-poly(CG)] dry, neutral DNA sequence,
using previously published models for stretched DNA. The calculated electronic
states are then used to parametrize an effective tight-binding model that can
describe electron hopping in the presence of environmental effects, such as the
presence of stray water molecules on the backbone or structural features of the
substrate. These effects introduce disorder in the model hamiltonian which
leads to electron localization. The localization length is smaller by several
orders of magnitude in stretched DNA relative to that in the unstretched
structure.


title: Ample subvarieties and rationally connected fibrations

abstract:
  Under some positivity assumptions, extension properties of rationally
connected fibrations from a submanifold to its ambient variety are studied.
Given a family of rational curves on a complex projective manifold X inducing a
covering family on a submanifold Y with ample normal bundle in X, the main
results relate, under suitable conditions, the associated rational connected
fiber structures on X and on Y. Applications of these results include an
extension theorem for Mori contractions of fiber type and a classification
theorem in the case Y has a structure of projective bundle or quadric
fibration.


title:
Bounds for Multiplicities of Unitary Representations of Cohomological
  Type in Spaces of Cusp Forms

abstract:
  Let $\Goo$ be a semisimple real Lie group with unitary dual $\Ghat$. The goal
of this note is to produce new upper bounds for the multiplicities with which
representations $\pi \in \Ghat$ of cohomological type appear in certain spaces
of cusp forms on $\Goo$.


title: Decoherence of Quantum-Enhanced Timing Accuracy

abstract:
  Quantum enhancement of optical pulse timing accuracy is investigated in the
Heisenberg picture. Effects of optical loss, group-velocity dispersion, and
Kerr nonlinearity on the position and momentum of an optical pulse are studied
via Heisenberg equations of motion. Using the developed formalism, the impact
of decoherence by optical loss on the use of adiabatic soliton control for
beating the timing standard quantum limit [Tsang, Phys. Rev. Lett. 97, 023902
(2006)] is analyzed theoretically and numerically. The analysis shows that an
appreciable enhancement can be achieved using current technology, despite an
increase in timing jitter mainly due to the Gordon-Haus effect. The decoherence
effect of optical loss on the transmission of quantum-enhanced timing
information is also studied, in order to identify situations in which the
enhancement is able to survive.


title: Stock market return distributions: from past to present

abstract:
  We show that recent stock market fluctuations are characterized by the
cumulative distributions whose tails on short, minute time scales exhibit power
scaling with the scaling index alpha > 3 and this index tends to increase
quickly with decreasing sampling frequency. Our study is based on
high-frequency recordings of the S&P500, DAX and WIG20 indices over the
interval May 2004 - May 2006. Our findings suggest that dynamics of the
contemporary market may differ from the one observed in the past. This effect
indicates a constantly increasing efficiency of world markets.


title:
Global well-posedness and scattering for the energy-critical, defocusing
  Hartree equation for radial data

abstract:
  We consider the defocusing, $\dot{H}^1$-critical Hartree equation for the
radial data in all dimensions $(n\geq 5)$. We show the global well-posedness
and scattering results in the energy space. The new ingredient in this paper is
that we first take advantage of the term $\displaystyle - \int_{I}\int_{|x|\leq
A|I|^{1/2}}|u|^{2}\Delta \Big(\frac{1}{|x|}\Big)dxdt$ in the localized Morawetz
identity to rule out the possibility of energy concentration, instead of the
classical Morawetz estimate dependent of the nonlinearity.


title: String inspired explanation for the super-acceleration of our universe

abstract:
  We investigate the effect of the bulk content in the general Gauss-Bonnet
braneworld on the evolution of the universe. We find that the Gauss-Bonnet term
and the combination of the dark radiation and the matter content of the bulk
play a crucial role in the universe evolution. We show that our model can
describe the super-acceleration of our universe with the equation of state of
the effective dark energy in agreement with observations.


title: Topological Free Entropy Dimension of in Unital C^*-algebras

abstract:
  The notion of topological free entropy dimension of $n-$tuples of elements in
a unital C$^*$ algebra was introduced by Voiculescu. In the paper, we compute
topological free entropy dimension of one self-adjoint element and topological
orbit dimension of one self-adjoint element in a unital C$^*$ algebra.
Moreover, we calculate the values of topological free entropy dimensions of
families of generators of some unital C$^*$ algebras (for example: irrational
rotation C$^*$ algebras or minimal tensor product of two reduced C$^*$ algebras
of free groups).


title: J/psi Production in an Equilibrating Partonic System

abstract:
  Any color singlet or octet ccbar pair is created at short distances and then
expands to a full size of J/psi. Such a dynamical evolution process is included
here in calculations for the J/psi number distribution as a function of
transverse momentum and rapidity in central Au-Au collisions at both RHIC and
LHC energies. The ccbar pairs are produced in the initial collision and in the
partonic system during the prethermal and thermal stages through the partonic
channels ab to ccbar [{2S+1}L_J] and ab to ccbar [{2S+1}L_J]x, and then they
dissociate in the latter two stages. Dissociation of ccbar in the medium occurs
via two reactions: (a) color singlet ccbar plus a gluon turns to color octet
ccbar, (b) color octet ccbar plus a gluon persists as color octet. There are
modest yields of ccbar in the prethermal stage at RHIC energy and through the
reactions ab to ccbar [{2S+1}L_J] at LHC energy for partons with large average
momentum in the prethermal stage at both collider energies and in the thermal
stage at LHC energy. Production from the partonic system competes with the
suppression of the initial yield in the deconfined medium. Consequently, a
bulge within -1.5<y<1.5 has been found for the J/psi number distribution and
the ratio of J/psi number distributions for Au-Au collisions to nucleon-nucleon
collisions. This bulge is caused by the partonic system and is thus an
indicator of a deconfined partonic medium. Based on this result we suggest the
rapidity region worth measuring in future experiments at RHIC and LHC to be
-3<y<3.


title: Reduced and Extended Weak Coupling Limit

abstract:
  We give an extended review of recent work on the extended weak coupling
limit. Background material on completely positive semigroups and their unitary
dilations is given, as well as a particularly easy construction of `quadratic
noises'.


title:
Complete Set of Polarization Transfer Observables for the $^{12}{\rm
  C}(p,n)$ Reaction at 296 MeV and 0$^{\circ}$

abstract:
  A complete set of polarization transfer observables has been measured for the
$^{12}{\rm C}(p,n)$ reaction at $T_p=296 {\rm MeV}$ and $\theta_{\rm
lab}=0^{\circ}$. The total spin transfer $\Sigma(0^{\circ})$ and the observable
$f_1$ deduced from the measured polarization transfer observables indicate that
the spin--dipole resonance at $E_x \simeq 7 {\rm MeV}$ has greater $2^-$
strength than $1^-$ strength, which is consistent with recent experimental and
theoretical studies. The results also indicate a predominance of the spin-flip
and unnatural-parity transition strength in the continuum. The exchange tensor
interaction at a large momentum transfer of $Q \simeq 3.6 {\rm fm}^{-1}$ is
discussed.


title: Learning from compressed observations

abstract:
  The problem of statistical learning is to construct a predictor of a random
variable $Y$ as a function of a related random variable $X$ on the basis of an
i.i.d. training sample from the joint distribution of $(X,Y)$. Allowable
predictors are drawn from some specified class, and the goal is to approach
asymptotically the performance (expected loss) of the best predictor in the
class. We consider the setting in which one has perfect observation of the
$X$-part of the sample, while the $Y$-part has to be communicated at some
finite bit rate. The encoding of the $Y$-values is allowed to depend on the
$X$-values. Under suitable regularity conditions on the admissible predictors,
the underlying family of probability distributions and the loss function, we
give an information-theoretic characterization of achievable predictor
performance in terms of conditional distortion-rate functions. The ideas are
illustrated on the example of nonparametric regression in Gaussian noise.


title: Hamiltonian formalism in Friedmann cosmology and its quantization

abstract:
  We propose a Hamiltonian formalism for a generalized
Friedmann-Roberson-Walker cosmology model in the presence of both a variable
equation of state (EOS) parameter $w(a)$ and a variable cosmological constant
$\Lambda(a)$, where $a$ is the scale factor. This Hamiltonian system containing
1 degree of freedom and without constraint, gives Friedmann equations as the
equation of motion, which describes a mechanical system with a variable mass
object moving in a potential field. After an appropriate transformation of the
scale factor, this system can be further simplified to an object with constant
mass moving in an effective potential field. In this framework, the $\Lambda$
cold dark matter model as the current standard model of cosmology corresponds
to a harmonic oscillator. We further generalize this formalism to take into
account the bulk viscosity and other cases. The Hamiltonian can be quantized
straightforwardly, but this is different from the approach of the
Wheeler-DeWitt equation in quantum cosmology.


title:
Optimal stimulus and noise distributions for information transmission
  via suprathreshold stochastic resonance

abstract:
  Suprathreshold stochastic resonance (SSR) is a form of noise enhanced signal
transmission that occurs in a parallel array of independently noisy identical
threshold nonlinearities, including model neurons. Unlike most forms of
stochastic resonance, the output response to suprathreshold random input
signals of arbitrary magnitude is improved by the presence of even small
amounts of noise. In this paper the information transmission performance of SSR
in the limit of a large array size is considered. Using a relationship between
Shannon's mutual information and Fisher information, a sufficient condition for
optimality, i.e. channel capacity, is derived. It is shown that capacity is
achieved when the signal distribution is Jeffrey's prior, as formed from the
noise distribution, or when the noise distribution depends on the signal
distribution via a cosine relationship. These results provide theoretical
verification and justification for previous work in both computational
neuroscience and electronics.


title: Three Different Types of Galaxy Alignment within Dark Matter Halos

abstract:
  Using a large galaxy group catalogue based on the Sloan Digital Sky Survey
Data Release 4 we measure three different types of intrinsic galaxy alignment
within groups: halo alignment between the orientation of the brightest group
galaxies (BGG) and the distribution of its satellite galaxies, radial alignment
between the orientation of a satellite galaxy and the direction towards its
BGG, and direct alignment between the orientation of the BGG and that of its
satellites. In agreement with previous studies we find that satellite galaxies
are preferentially located along the major axis. In addition, on scales r < 0.7
Rvir we find that red satellites are preferentially aligned radially with the
direction to the BGG. The orientations of blue satellites, however, are
perfectly consistent with being isotropic. Finally, on scales r < 0.1 \Rvir, we
find a weak but significant indication for direct alignment between satellites
and BGGs. We briefly discuss the implications for weak lensing measurements.


title: Proto-Neutron Star Winds, Magnetar Birth, and Gamma-Ray Bursts

abstract:
  We begin by reviewing the theory of thermal, neutrino-driven proto-neutron
star (PNS) winds. Including the effects of magnetic fields and rotation, we
then derive the mass and energy loss from magnetically-driven PNS winds for
both relativistic and non-relativistic outflows, including important
multi-dimensional considerations. With these simple analytic scalings we argue
that proto-magnetars born with ~ millisecond rotation periods produce
relativistic winds just a few seconds after core collapse with luminosities,
timescales, mass-loading, and internal shock efficiencies favorable for
producing long-duration gamma-ray bursts.


title: A very massive runaway star from Cygnus OB2

abstract:
  Aims: We analyze the available information on the star BD+43 3654 to
investigate the possibility that it may have had its origin in the massive OB
association Cygnus OB2.
  Methods: We present new spectroscopic observations allowing a reliable
spectral classification of the star, and discuss existing MSX observations of
its associated bow shock and astrometric information not previously studied.
  Results: Our observations reveal that BD+43 3654 is a very early and luminous
star of spectral type O4If, with an estimated mass of (70 +/- 15) solar masses
and an age of about 1.6 Myr. The high spatial resolution of the MSX
observations allows us to determine its direction of motion in the plane of the
sky by means of the symmetry axis of the well-defined bow shock, which matches
well the orientation expected from the proper motion. Tracing back its path
across the sky we find that BD+43 3654 was located near the central, densest
region of Cygnus OB2 at a time in the past similar to its estimated age.
  Conclusions: BD+43 3654 turns out to be one of the three most massive runaway
stars known, and it most likely formed in the central region of Cygnus OB2. A
runaway formation mechanism by means of dynamical ejection is consistent with
our results.


title: Optical spectrum of the post-AGB star HD56126 in the region 4010-8790 AA

abstract:
  We studied in detail the optical spectrum of the post-AGB star HD56126
(IRAS07134+1005). We use high resolution spectra (R=25000 and 60000) obtained
with the echelle spectrographs of the 6-m telescope. About one and a half
thousand absorptions of neutral atoms and ions, absorption bands of C_2, CN,
and CH molecules, and interstellar bands (DIBs) are identified in the 4010 to
8790 AA wavelength region, and the depths and radial velocities of these
spectral features are measured. Differences are revealed between the variations
of the radial velocities measured from spectral features of different
excitation. In addition to the well-known variability of the Halpha profile, we
found variations in the profiles of a number of FeII, YII, and BaII lines. We
also produce an atlas of the spectrum of HD56126 and its comparison staralpha
Per. The full version of the atlas is available in electronic form from
Web-address: http://www.sao.ru/hq/ssl/Atlas/Atlas.html


title:
Generation of Large Number-Path Entanglement Using Linear Optics and
  Feed-Forward

abstract:
  We show how an idealised measurement procedure can condense photons from two
modes into one, and how, by feeding forward the results of the measurement, it
is possible to generate efficiently superpositions of components for which only
one mode is populated, commonly called ``N00N states''. For the basic
procedure, sources of number states leak onto a beam splitter, and the output
ports are monitored by photodetectors. We find that detecting a fixed fraction
of the input at one output port suffices to direct the remainder to the same
port with high probability, however large the initial state. When instead
photons are detected at both ports, Schr\"{o}dinger cat states are produced. We
describe a circuit for making the components of such a state orthogonal, and
another for subsequent conversion to a N00N state. Our approach scales
exponentially better than existing proposals. Important applications include
quantum imaging and metrology.


title: Finite branch solutions to Painleve VI around a fixed singular point

abstract:
  Every finite branch solutions to the sixth Painleve equation around a fixed
singular point is an algebraic branch solution. In particular a global solution
is an algebraic solution if and only if it is finitely many-valued globally.
The proof of this result relies on algebraic geometry of Painleve VI,
Riemann-Hilbert correspondence, geometry and dynamics on cubic surfaces,
resolutions of Kleinian singularities, and power geometry of algebraic
differential equations. In the course of the proof we are also able to classify
all finite branch solutions up to Backlund transformations.