title: Dark Energy from structure: a status report

abstract:
  The effective evolution of an inhomogeneous universe model in any theory of
gravitation may be described in terms of spatially averaged variables. In
Einstein's theory, restricting attention to scalar variables, this evolution
can be modeled by solutions of a set of Friedmann equations for an effective
volume scale factor, with matter and backreaction source terms. The latter can
be represented by an effective scalar field (`morphon field') modeling Dark
Energy.
  The present work provides an overview over the Dark Energy debate in
connection with the impact of inhomogeneities, and formulates strategies for a
comprehensive quantitative evaluation of backreaction effects both in
theoretical and observational cosmology. We recall the basic steps of a
description of backreaction effects in relativistic cosmology that lead to
refurnishing the standard cosmological equations, but also lay down a number of
challenges and unresolved issues in connection with their observational
interpretation.
  The present status of this subject is intermediate: we have a good
qualitative understanding of backreaction effects pointing to a global
instability of the standard model of cosmology; exact solutions and
perturbative results modeling this instability lie in the right sector to
explain Dark Energy from inhomogeneities. It is fair to say that, even if
backreaction effects turn out to be less important than anticipated by some
researchers, the concordance high-precision cosmology, the architecture of
current N-body simulations, as well as standard perturbative approaches may all
fall short in correctly describing the Late Universe.


title:
X-Ray Nuclei in Radio Galaxies: Exploring the Roles of Hot and Cold Gas
  Accretion

abstract:
  We present results from Chandra and XMM-Newton spectroscopic observations of
the nuclei of z<0.5 radio galaxies and quasars from the 3CRR catalog, and
examine in detail the dichotomy in the properties of low- and high-excitation
radio galaxies. The X-ray spectra of low-excitation sources (those with weak or
absent optical emission lines) are dominated by unabsorbed emission from a
parsec-scale jet, with no contribution from accretion-related emission. These
sources show no evidence for an obscuring torus, and are likely to accrete in a
radiatively inefficient manner. High-excitation sources (those with prominent
optical emission lines), on the other hand, show a significant contribution
from a radiatively efficient accretion disk, which is heavily absorbed in the
X-ray when they are oriented close to edge-on with respect to the observer.
However, the low-excitation/high-excitation division does not correspond to the
FRI/FRII division: thus the Fanaroff-Riley dichotomy remains a consequence of
the interaction between the jet and the hot-gas environment through which it
propagates. Finally, we suggest that accretion of the hot phase of the IGM is
sufficient to power all low-excitation radio sources, while high-excitation
sources require an additional contribution from cold gas that in turn forms the
cold disk and torus. This model explains a number of properties of the
radio-loud active galaxy population, and has important implications for AGN
feedback mechanisms.


title: The modular multiplication operator and the quantized bakers maps

abstract:
  The modular multiplication operator, a central subroutine in Shor's factoring
algorithm, is shown to be a coherent superposition of two quantum bakers maps
when the multiplier is 2. The classical limit of the maps being completely
chaotic, it is shown that there exist perturbations that push the modular
multiplication operator into regimes of generic quantum chaos with spectral
fluctuations that are those of random matrices. For the initial state of
relevance to Shor's algorithm we study fidelity decay due to phase and bit-flip
errors in a single qubit and show exponential decay with shoulders at multiples
or half-multiples of the order. A simple model is used to gain some
understanding of this behavior.


title: On Hilbert's construction of positive polynomials

abstract:
  In 1888, Hilbert described how to find real polynomials in more than one
variable which take only non-negative values but are not a sum of squares of
polynomials. His construction was so restrictive that no explicit examples
appeared until the late 1960s. We revisit and generalize Hilbert's construction
and present many such polynomials.


title: $pp \to pp\pi^0$ near threshold in pionless effective theory

abstract:
  The total cross section of the $pp\to pp\pi^0$ reaction near threshold is
calculated in pionless effective field theory with a di-baryon and external
pions. The amplitudes for a leading one-body and subleading contact neutral
pion production vertex are obtained including the initial and final state
interactions. After estimating a low-energy constant in the contact vertex, we
compare our results for the total cross section with the experimental data.


title:
Variable Selection and Model Averaging in Semiparametric Overdispersed
  Generalized Linear Models

abstract:
  We express the mean and variance terms in a double exponential regression
model as additive functions of the predictors and use Bayesian variable
selection to determine which predictors enter the model, and whether they enter
linearly or flexibly. When the variance term is null we obtain a generalized
additive model, which becomes a generalized linear model if the predictors
enter the mean linearly. The model is estimated using Markov chain Monte Carlo
simulation and the methodology is illustrated using real and simulated data
sets.


title: The spectrum of heavy-tailed random matrices

abstract:
  Let $X_N$ be an $N\ts N$ random symmetric matrix with independent
equidistributed entries. If the law $P$ of the entries has a finite second
moment, it was shown by Wigner \cite{wigner} that the empirical distribution of
the eigenvalues of $X_N$, once renormalized by $\sqrt{N}$, converges almost
surely and in expectation to the so-called semicircular distribution as $N$
goes to infinity. In this paper we study the same question when $P$ is in the
domain of attraction of an $\alpha$-stable law. We prove that if we renormalize
the eigenvalues by a constant $a_N$ of order $N^{\frac{1}{\alpha}}$, the
corresponding spectral distribution converges in expectation towards a law
$\mu_\alpha$ which only depends on $\alpha$. We characterize $\mu_\alpha$ and
study some of its properties; it is a heavy-tailed probability measure which is
absolutely continuous with respect to Lebesgue measure except possibly on a
compact set of capacity zero.


title: Splay Trees, Davenport-Schinzel Sequences, and the Deque Conjecture

abstract:
  We introduce a new technique to bound the asymptotic performance of splay
trees. The basic idea is to transcribe, in an indirect fashion, the rotations
performed by the splay tree as a Davenport-Schinzel sequence S, none of whose
subsequences are isomorphic to fixed forbidden subsequence. We direct this
technique towards Tarjan's deque conjecture and prove that n deque operations
require O(n alpha^*(n)) time, where alpha^*(n) is the minimum number of
applications of the inverse-Ackermann function mapping n to a constant. We are
optimistic that this approach could be directed towards other open conjectures
on splay trees such as the traversal and split conjectures.


title: Algebraic hierarchy of logics unifying fuzzy logic and quantum logic

abstract:
  In this paper, a short survey about the concepts underlying general logics is
given. In particular, a novel rigorous definition of a fuzzy negation as an
operation acting on a lattice to render it into a fuzzy logic is presented.
According to this definition, a fuzzy negation satisfies the weak double
negation condition, requiring double negation to be expansive, the antitony
condition, being equivalent to the disjunctive De Morgan law and thus
warranting compatibility of negation with the lattice operations, and the
Boolean boundary condition stating that the universal bounds of the lattice are
the negation of each other. From this perspective, the most general logics are
fuzzy logics, containing as special cases paraconsistent (quantum) logics,
quantum logics, intuitionistic logics, and Boolean logics, each of which given
by its own algebraic restrictions. New examples of a non-contradictory logic
violating the conjunctive De Morgan law, and of a typical non-orthomodular
fuzzy logic along with its explicit lattice representation are given.


title: Bar imprints on the inner gas kinematics of M33

abstract:
  We present measurements of the stellar and gaseous velocities in the central
5' of the Local Group spiral M33. The data were obtained with the ARC 3.5m
telescope. Blue and red spectra with resolutions from 2 to 4\AA covering the
principal gaseous emission and stellar absorption lines were obtained along the
major and minor axes and six other position angles. The observed radial
velocities of the ionized gas along the photometric major axis of M33 remain
flat at ~22 km s^{-1} all the way into the center, while the stellar velocities
show a gradual rise from zero to 22 km s^{-1} over that same region. The
central star cluster is at or very close to the dynamical center, with a
velocity that is in accordance with M33's systemic velocity to within our
uncertainties. Velocities on the minor axis are non-zero out to about 1' from
the center in both the stars and gas. Together with the major axis velocities,
they point at significant deviations from circular rotation. The most likely
explanation for the bulk of the velocity patterns are streaming motions along a
weak inner bar with a PA close to that of the minor axis, as suggested by
previously published IR photometric images. The presence of bar imprints in M33
implies that all major Local Group galaxies are barred. The non-circular
motions over the inner 200 pc make it difficult to constrain the shape of M33's
inner dark matter halo profile. If the non-circular motions we find in this
nearby Sc galaxy are present in other more distant late-type galaxies, they
might be difficult to recognize.


title:
Phonon-driven ultrafast exciton dissociation at donor-acceptor polymer
  heterojunctions

abstract:
  A quantum-dynamical analysis of phonon-driven exciton dissociation at polymer
heterojunctions is presented, using a hierarchical electron-phonon model
parameterized for three electronic states and 24 vibrational modes. Two
interfering decay pathways are identified: a direct charge separation, and an
indirect pathway via an intermediate bridge state. Both pathways depend
critically on the dynamical interplay of high-frequency C=C stretch modes and
low-frequency ring-torsional modes. The ultrafast, highly non-equilibrium
dynamics is consistent with time-resolved spectroscopic observations.


title:
Beyond the Maxwell Limit: Thermal Conduction in Nanofluids with
  Percolating Fluid Structures

abstract:
  In a well-dispersed nanofluid with strong cluster-fluid attraction, thermal
conduction paths can arise through percolating amorphous-like interfacial
structures. This results in a thermal conductivity enhancement beyond the
Maxwell limit of 3*phi, with phi being the nanoparticle volume fraction. Our
findings from non-equilibrium molecular dynamics simulations, which are
amenable to experimental verification, can provide a theoretical basis for the
development of future nanofluids.


title: Filtered Hirsch Algebras

abstract:
  Motivated by the cohomology theory of loop spaces, we consider a special
class of higher order homotopy commutative differential graded algebras and
construct the filtered Hirsch model for such an algebra $A$. When $x\in H(A)$
with $\mathbb{Z}$ coefficients and $x^{2}=0,$ the symmetric Massey products $%
\langle x\rangle ^{n}$ with $n\geq 3$ have a finite order (whenever defined).
However, if $\Bbbk $ is a field of characteristic zero, $\langle x\rangle ^{n}$
is defined and vanishes in $H(A\otimes \Bbbk )$ for all $n$. If $p$ is an odd
prime, the Kraines formula $\langle x\rangle ^{p}=-\beta \mathcal{P}_{1}(x)$
lifts to $H^{\ast }(A\otimes {\mathbb{Z}}_{p}).$ Applications of the existence
of polynomial generators in the loop homology and the Hochschild cohomology
with a $G$-algebra structure are given.


title: Chromospheric Dynamics and Line Formation

abstract:
  The solar chromosphere is very dynamic, due to the presence of large
amplitude hydrodynamic waves. Their propagation is affected by NLTE radiative
transport in strong spectral lines, which can in turn be used to diagnose the
dynamics of the chromosphere. We give a basic introduction into the equations
of NLTE radiation hydrodynamics and describe how they are solved in current
numerical simulations. The comparison with observation shows that
one-dimensional codes can describe strong brightenings quite well, but the
overall chromospheric dynamics appears to be governed by three-dimensional
shock propagation.


title:
An explicit formula for the action of a finite group on a commutative
  ring

abstract:
  Let G be a group which acts on a commutative ring k. We exhibit an induction
formula which expresses an element x_G with tr_G(x_G)=1 by elements x_P with
tr_P(x_P)=1, where P varies over prime order subgroups of P.


title: Charge radius and dipole response of $^{11}$Li

abstract:
  We investigate the consistency of the measured charge radius and dipole
response of $^{11}$Li within a three-body model. We show how these observables
are related to the mean square distance between the $^9$Li core and the center
of mass of the two valence neutrons. In this representation we find by
considering the effect of smaller corrections that the discrepancy between the
results of the two measurements is of the order of 1.5$\sigma$. We also
investigate the sensitivity to the three-body structure of $^{11}$Li and find
that the charge radius measurement favors a model with a 50% s-wave component
in the ground state of the two-neutron halo, whereas the dipole response is
consistent with a smaller s-wave component of about 25% value.


title:
On positive solutions of minimal growth for singular p-Laplacian with
  potential term

abstract:
  Let $\Omega$ be a domain in $\mathbb{R}^d$, $d\geq 2$, and $1<p<\infty$. Fix
$V\in L_{\mathrm{loc}}^\infty(\Omega)$. Consider the functional $Q$ and its
G\^{a}teaux derivative $Q^\prime$ given by
  Q(u):=\frac{1}{p}\int_\Omega (|\nabla u|^p+V|u|^p)\dx,
  Q^\prime (u):=-\nabla\cdot(|\nabla u|^{p-2}\nabla u)+V|u|^{p-2}u.
  It is assumed that $Q\geq 0$ on $C_0^\infty(\Omega)$. In a previous paper we
discussed relations between the absence of weak coercivity of the functional
$Q$ on $C_0^\infty(\Omega)$ and the existence of a generalized ground state. In
the present paper we study further relationships between functional-analytic
properties of the functional $Q$ and properties of positive solutions of the
equation $Q^\prime (u)=0$.


title: Evidence of Exponential Decay Emission in the Swift Gamma-ray Bursts

abstract:
  We present a systematic study of the steep decay emission from gamma-ray
bursts (GRBs) observed by the Swift X-Ray Telescope (XRT). In contrast to the
analysis described in recent literature, we produce composite Burst Alert
Telescope (BAT) and XRT light curves by extrapolating the XRT data (2-10 keV)
into the BAT energy range (15-25 keV) rather than extrapolating the BAT data
into the XRT energy band (0.3-10 keV). Based on the fits to the composite light
curves, we have confirmed the existence of an exponential decay component which
smoothly connects the BAT prompt data to the XRT steep decay for several GRBs.
We also find that the XRT steep decay for some of the bursts can be well fit by
a combination of a power-law with an exponential decay model. We discuss this
exponential component within the frame work of both the internal and the
external shock model.


title: Influence of Vacancies on the Nanoparticle Pulsation

abstract:
  Computer modeling of the one-dimensional and three-dimensional nanoparticles
with Van-der-Waals interaction was performed. The arrangement of atoms was
defined on the grounds of an energy minimum. The calculations have shown that
in the presence of vacancies in a nanoparticle and the account of a relaxation
and oscillations the nanoparticle will pulse. This pulsation on distance
between atoms of a nanoparticle is observed in both one-dimensional and a
three-dimensional cases.


title: Neutral current coherent pion production

abstract:
  We investigate the neutrino induced coherent pion production reaction at low
and intermediate energies. The model includes pion, nucleon and Delta(1232)
resonance as the relevant hadronic degrees of freedom. Nuclear medium effects
on the production mechanisms and pion distortion are taken into account. We
obtain that the dominance of the Delta excitation holds due to large
cancellations among the background contributions. We consider two sets of
vector and axial-vector N-Delta transition form-factors, evidencing the strong
sensitivity of the results to the axial coupling C5A(0). The differences
between neutrino and antineutrino cross sections, emerging from interference
terms, are also discussed.


title:
Cyclic (v;r,s;lambda) difference families with two base blocks and v <=
  50

abstract:
  We construct many new cyclic (v;r,s;lambda) difference families with v less
than or equal 50. In particular we construct the difference families with
parameters (45;18,10;9), (45;22,22;21), (47;21,12;12), (47;19,15;12),
(47;22,14;14), (48;20,10;10), (48;24,4;12), (50;25,20;20) for which the
existence question was an open problem. The (45;22,22;21) difference family
gives a BIBD with parameters v=45, b=90, r=44, k=22 and lambda=21, and the one
with parameters (50;25,20;20) gives a pair of binary sequences of length 50
with zero periodic autocorrelation function (the periodic analog of a Golay
pair). We also construct nine new D-optimal designs. A normal form for cyclic
difference families is proposed and used effectively in compiling the list of
known and new difference families.


title: General Very Special Relativity is Finsler Geometry

abstract:
  We ask whether Cohen and Glashow's Very Special Relativity model for Lorentz
violation might be modified, perhaps by quantum corrections, possibly producing
a curved spacetime with a cosmological constant. We show that its symmetry
group ISIM(2) does admit a 2-parameter family of continuous deformations, but
none of these give rise to non-commutative translations analogous to those of
the de Sitter deformation of the Poincar\'e group: spacetime remains flat. Only
a 1-parameter family DISIM_b(2) of deformations of SIM(2) is physically
acceptable. Since this could arise through quantum corrections, its
implications for tests of Lorentz violations via the Cohen-Glashow proposal
should be taken into account. The Lorentz-violating point particle action
invariant under DISIM_b(2) is of Finsler type, for which the line element is
homogeneous of degree 1 in displacements, but anisotropic. We derive
DISIM_b(2)-invariant wave equations for particles of spins 0, 1/2 and 1. The
experimental bound, $|b|<10^{-26}$, raises the question ``Why is the
dimensionless constant $b$ so small in Very Special Relativity?''


title: Morita equivalence of Poisson manifold via stack groupoids

abstract:
  This is a condensed exposition of the results of a future work, based on a
talk of the second author at the Oberwolfach workshop "Poisson Geometry", April
30--4 May 2007.


title:
Benefit of Delay on the Diversity-Multiplexing Tradeoffs of MIMO
  Channels with Partial CSI

abstract:
  This paper re-examines the well-known fundamental tradeoffs between rate and
reliability for the multi-antenna, block Rayleigh fading channel in the high
signal to noise ratio (SNR) regime when (i) the transmitter has access to
(noiseless) one bit per coherence-interval of causal channel state information
(CSI) and (ii) soft decoding delays together with worst-case delay guarantees
are acceptable. A key finding of this work is that substantial improvements in
reliability can be realized with a very short expected delay and a slightly
longer (but bounded) worst-case decoding delay guarantee in communication
systems where the transmitter has access to even one bit per coherence interval
of causal CSI. While similar in spirit to the recent work on communication
systems based on automatic repeat requests (ARQ) where decoding failure is
known at the transmitter and leads to re-transmission, here transmit
side-information is purely based on CSI. The findings reported here also lend
further support to an emerging understanding that decoding delay (related to
throughput) and codeword blocklength (related to coding complexity and delays)
are distinctly different design parameters which can be tuned to control
reliability.


title: Preheating in Derivatively-Coupled Inflation Models

abstract:
  We study preheating in theories where the inflaton couples derivatively to
scalar and gauge fields. Such couplings may dominate in natural models of
inflation, in which the flatness of the inflaton potential is related to an
approximate shift symmetry of the inflaton. We compare our results with
previously studied models with non-derivative couplings. For sufficiently heavy
scalar matter, parametric resonance is ineffective in reheating the universe,
because the couplings of the inflaton to matter are very weak. If scalar matter
fields are light, derivative couplings lead to a mild long-wavelength
instability that drives matter fields to non-zero expectation values. In this
case however, long-wavelength fluctuations of the light scalar are produced
during inflation, leading to a host of cosmological problems. In contrast,
axion-like couplings of the inflaton to a gauge field do not lead to production
of long-wavelength fluctuations during inflation. However, again because of the
weakness of the couplings to the inflaton, parametric resonance is not
effective in producing gauge field quanta.


title: Stimulated radiative laser cooling

abstract:
  Building a refrigerator based on the conversion of heat into optical energy
is an ongoing engineering challenge. Under well-defined conditions, spontaneous
anti-Stokes fluorescence of a dopant material in a host matrix is capable of
lowering the host temperature. The fluorescence is conveying away a part of the
thermal energy stored in the vibrational oscillations of the host lattice. In
particular, applying this principle to the cooling of (solid-state) lasers
opens up many potential device applications, especially in the domain of
high-power lasers. In this paper, an alternative optical cooling scheme is
outlined, leading to radiative cooling of solid-state lasers. It is based on
converting the thermal energy stored in the host, into optical energy by means
of a stimulated nonlinear process, rather than a spontaneous process. This
should lead to better cooling efficiencies and a higher potential of applying
the principle for device applications.


title:
Confinement for all values of the coupling in four-dimensional SU(2)
  gauge theory

abstract:
  A derivation is given from first principles of the fact that the SU(2) gauge
theory is in a confining phase for all values of the coupling $0 < g < \infty$
defined at lattice spacing (UV regulator) $a$, and space-time dimension $d \leq
4$. The strategy is to employ approximate RG decimation transformations of the
potential moving type which give both upper and lower bounds on the partition
function at each successive decimation step. By interpolation between these
bounds an exact representation of the partition function is obtained on
progressively coarser lattices. In the same manner, one obtains a
representation of the partition function in the presence of external center
flux. Under successive decimations the flow of the effective action in these
representations is constrained by that in the upper and lower bounds which are
easily explicitly computable. Confining behavior for the vortex free energy
order parameter (ratio of partition functions with and without external flux),
hence `area law' for the Wilson loop, is the result for any initial coupling.
Keeping the string tension fixed determines the dependence $g(a)$, which is
such that $g(a) \to 0$ for $a \to 0$.


title:
Physical properties of a new cuprate superconductor
  Pr_2Ba_4Cu_7O_{15-\delta}

abstract:
  We present studies of the thermal, magnetic and electrical transport
properties of reduced polycrystalline Pr_2Ba_4Cu_7O_{15-\delta} (Pr247) showing
a superconducting transition at Tc = 10 - 16 K and compare them with those of
as-sintered non-superconducting Pr247. The electrical resistivity in the normal
state exhibited T2 dependence up to approximately 150 K. A clear specific heat
anomaly was observed at Tc for Pr247 reduced in a vacuum for 24 hrs, proving
the bulk nature of the superconducting state. By the reduction treatment, the
magnetic ordering temperature TN of Pr moments decreased from 16 to 11 K, and
the entropy associated with the ordering increased, while the effective
paramagnetic moments obtained from the DC magnetic susceptibility varied from
2.72 to 3.13 mB. The sign of Hall coefficient changed from positive to negative
with decreasing temperature in the normal state of a superconducting Pr247,
while that of as-sintered one was positive down to 5 K. The electrical
resistivity under high magnetic fields was found to exhibit T^a dependence (a =
0.08 - 0.4) at low temperatures. A possibility of superconductivity in the
so-called CuO double chains is discussed.


title:
Gauge invariant Lagrangian construction for massive bosonic mixed
  symmetry higher spin fields

abstract:
  We develop the BRST approach to gauge invariant Lagrangian construction for
the massive mixed symmetry integer higher spin fields described by the rank-two
Young tableaux in arbitrary dimensional Minkowski space. The theory is
formulated in terms of auxiliary Fock space. No off-shell constraints on the
fields and the gauge parameters are imposed. The approach under consideration
automatically leads to a gauge invariant Lagrangian for massive theory with all
appropriate Stuckelberg fields. It is shown that all the restrictions defining
an irreducible representation of the Poincare group arise from Lagrangian
formulation as a consequence of the equations of motion and gauge
transformations. As an example of the general procedure, we derive the
gauge-invariant Lagrangian for massive rank-2 antisymmetric tensor field
containing the complete set of auxiliary fields and gauge parameters.


title:
Design of Multistage Decimation Filters Using Cyclotomic Polynomials:
  Optimization and Design Issues

abstract:
  This paper focuses on the design of multiplier-less decimation filters
suitable for oversampled digital signals. The aim is twofold. On one hand, it
proposes an optimization framework for the design of constituent decimation
filters in a general multistage decimation architecture. The basic building
blocks embedded in the proposed filters belong, for a simple reason, to the
class of cyclotomic polynomials (CPs): the first 104 CPs have a z-transfer
function whose coefficients are simply {-1,0,+1}. On the other hand, the paper
provides a bunch of useful techniques, most of which stemming from some key
properties of CPs, for designing the proposed filters in a variety of
architectures. Both recursive and non-recursive architectures are discussed by
focusing on a specific decimation filter obtained as a result of the
optimization algorithm.
  Design guidelines are provided with the aim to simplify the design of the
constituent decimation filters in the multistage chain.


title:
Strain distribution in quantum dot of arbitrary polyhedral shape:
  Analytical solution in closed form

abstract:
  An analytical expression of the strain distribution due to lattice mismatch
is obtained in an infinite isotropic elastic medium (a matrix) with a
three-dimensional polyhedron-shaped inclusion (a quantum dot). The expression
was obtained utilizing the analogy between electrostatic and elastic theory
problems. The main idea lies in similarity of behavior of point charge electric
field and the strain field induced by point inclusion in the matrix. This opens
a way to simplify the structure of the expression for the strain tensor. In the
solution, the strain distribution consists of contributions related to faces
and edges of the inclusion. A contribution of each face is proportional to the
solid angle at which the face is seen from the point where the strain is
calculated. A contribution of an edge is proportional to the electrostatic
potential which would be induced by this edge if it is charged with a constant
linear charge density. The solution is valid for the case of inclusion having
the same elastic constants as the matrix. Our method can be applied also to the
case of semi-infinite matrix with a free surface. Three particular cases of the
general solution are considered--for inclusions of pyramidal, truncated
pyramidal, and "hut-cluster" shape. In these cases considerable simplification
was achieved in comparison with previously published solutions. A
generalization of the obtained solution to the case of anisotropic media is
discussed.


title:
Interplay of polarization geometry and rotational dynamics in high
  harmonic generation from coherently rotating linear molecule

abstract:
  Recent reports on intense-field pump-probe experiments for high harmonic
generation from coherently rotating linear molecules, have revealed remarkable
characteristic effects of the simultaneous variation of the polarization
geometry and the time delay on the high harmonic signals. We analyze the
effects and give a unified theoretical account of the experimental observations


title: Mod\'elisation Dynamique d'un Robot Parall\`ele \`a 3-DDL : l'Orthoglide

abstract:
  In this article, we propose a method for calculation of the inverse and
direct dynamic models of the Orthoglide, a parallel robot with threedegrees of
freedom in translation. These models are calculated starting from the elements
of the dynamic model of the kinematic chain structure and equations of
Newton-Euler applied to the platform. These models are obtained in explicit
form having an interesting physical interpretation.


title:
Weakly infinitely divisible measures on some locally compact Abelian
  groups

abstract:
  On the torus group, on the group of p-adic integers and on the p-adic
solenoid, we give a construction of an arbitrary weakly infinitely divisible
probability measure using a random element with values in a product of
(possibly infinitely many) subgroups of the real numbers. As a special case of
our results, we have a new construction of the Haar measure on the p-adic
solenoid.


title:
Nucleosynthesis in Core-Collapse Supernovae and GRB--Metal-Poor Star
  Connection

abstract:
  We review the nucleosynthesis yields of core-collapse supernovae (SNe) for
various stellar masses, explosion energies, and metallicities. Comparison with
the abundance patterns of metal-poor stars provides excellent opportunities to
test the explosion models and their nucleosynthesis. We show that the abundance
patterns of extremely metal-poor (EMP) stars, e.g., the excess of C, Co, Zn
relative to Fe, are in better agreement with the yields of hyper-energetic
explosions (Hypernovae, HNe) rather than normal supernovae.
  We note that the variation of the abundance patterns of EMP stars are related
to the diversity of the Supernova-GRB connection. We summarize the diverse
properties of (1) GRB-SNe, (2) Non-GRB HNe/SNe, (3) XRF-SN, and (4) Non-SN GRB.
In particular, the Non-SN GRBs (dark hypernovae) have been predicted in order
to explain the origin of C-rich EMP stars. We show that these variations and
the connection can be modeled in a unified manner with the explosions induced
by relativistic jets. Finally, we examine whether the most luminous supernova
2006gy can be consistently explained with the pair-instability supernova model.


title:
On the Origin of the Kinematical Differences Between the Stellar Halo
  and the Old Globular Cluster System in the Large Magellanic Cloud

abstract:
  We discuss structural and kinematical properties of the stellar halo and the
old globular cluster system (GCS) in the Large Magellanic Cloud (LMC) based on
numerical simulations of the LMC formation. We particularly discuss the
observed possible GCS's rotational kinematics (V/sigma > 2) that appears to be
significantly different from the stellar halo's one with a large velocity
dispersion (~50 km/s). We consider that both halo field stars and old GCs can
originate from low-mass subhalos virialized at high redshifts (z >6). We
investigate the final dynamical properties of the two old components in the
LMC's halo formed from merging of low-mass subhalos with field stars and GCs.
We find that the GCS composed of old globular clusters (GCs) formed at high
redshifts (z > 6) has little rotation (V/sigma ~0.4) and structure and
kinematics similar to those of the stellar halo. This inconsistency between the
simulated GCS's kinematics and the observed one is found to be seen in models
with different parameters. This inconsistency therefore implies that if old,
metal-poor GCs in the LMC have rotational kinematics, they are highly unlikely
to originate from the low-mass subhalos that formed the stellar halo. We thus
discuss a scenario in which the stellar halo was formed from low-mass subhalos
with no/few GCs whereas the GCS was formed at the very early epoch of the LMC's
disk formation via dissipative minor and major merging of gas-rich subhalos and
gas infall. We suggest that there can be a threshold subhalo mass above which
GCs can be formed within subhalos at high redshifts and thus that this
threshold causes differences in physical properties between stellar halos and
GCSs in less luminous galaxies like the LMC.


title: Real Closed Rings and Real Closed * Rings

abstract:
  Here we try to distinguish and compare different notions of real closedness
mainly one developed by N. Schwartz in his Habilitationschrift and the other
developed by A. Sankaranand K. Varadarajan which we shall call real closed *.
We stick to the definition of real closed rings as defined and characterized N.
Schwartz and we try to determine and characterize real closed rings that are
real closed *. The main result is that real closed rings have unique real
closure * and that real closure of real closed * rings arent necessarily real
closed *.


title:
Solutions of the problem of Erd\"os-Sierpi\'nski:
  $\sigma(n)=\sigma(n+1)$

abstract:
  For $n\leq 1.5 \cdot 10^{10}$, we have found a total number of 1268 solutions
to the Erd\"os-Sierpi\'nski problem finding positive integer solutions of
$\sigma(n)=\sigma(n+1)$, where $\sigma(n)$ is the sum of the positive divisors
of n. On the basis of that set of solutions the following empirical properties
are enunciated: first, all the $\sigma(n)$, $n$ being a solution, are divisible
by 6; second, the repetition of solutions leads to the formulation of a new
problem: \emph{Find the natural numbers $n$ such that
$\sigma(n)=\sigma(n+1)=\sigma(n+k)=\sigma(n+k+1)$ for some positive integer
$k$}. A third empirical property concerns the asymptotic behavior of the
function of $n$ that gives the number of solutions for $m$ less or equal to
$n$, which we find to be as $n^{1/3}$. Finally some theorems related to the
Erd\"os-Sierpi\'nski problem are enunciated and proved.


title:
Word statistics in Blogs and RSS feeds: Towards empirical universal
  evidence

abstract:
  We focus on the statistics of word occurrences and of the waiting times
between such occurrences in Blogs. Due to the heterogeneity of words'
frequencies, the empirical analysis is performed by studying classes of
"frequently-equivalent" words, i.e. by grouping words depending on their
frequencies. Two limiting cases are considered: the dilute limit, i.e. for
those words that are used less than once a day, and the dense limit for
frequent words. In both cases, extreme events occur more frequently than
expected from the Poisson hypothesis. These deviations from Poisson statistics
reveal non-trivial time correlations between events that are associated with
bursts of activities. The distribution of waiting times is shown to behave like
a stretched exponential and to have the same shape for different sets of words
sharing a common frequency, thereby revealing universal features.


title:
A generalization of Hamilton's differential Harnack inequality for the
  Ricci flow

abstract:
  In [10], R. Hamilton established a differential Harnack inequality for
solutions to the Ricci flow with nonnegative curvature operator. We show that
this inequality holds under the weaker condition that M x R^2 has nonnegative
isotropic curvature.


title: GJ 900: A new hierarchical system with low-mass components

abstract:
  Speckle interferometric observations made with the 6 m telescope of the
Special Astrophysical Observatory of the Russian Academy of Sciences in 2000
revealed the triple nature of the nearby ($\pi_{Hip}=51.80\pm1.74$ mas)
low-mass young ($\approx200$ Myr) star GJ 900. The configuration of the triple
system allowed it to be dynamically unstable. Differential photometry performed
from 2000 through 2004 yielded $I$- and $K$-band absolute magnitudes and
spectral types for the components to be $I_{A}$=6.66$\pm$0.08,
$I_{B}$=9.15$\pm$0.11, $I_{C}$=10.08$\pm$0.26, $K_{A}$=4.84$\pm$0.08,
$K_{B}$=6.76$\pm$0.20, $K_{C}$=7.39$\pm$0.31, $Sp_{A}$$\approx$K5--K7,
$Sp_{B}$$\approx$M3--M4, $Sp_{C}$$\approx$M5--M6. The ``mass--luminosity''
relation is used to estimate the individual masses of the components:
$\mathcal{M}_{A}$$\approx0.64\mathcal{M}_{\odot}$,
$\mathcal{M}_{B}$$\approx0.21\mathcal{M}_{\odot}$,
$\mathcal{M}_{C}$$\approx0.13\mathcal{M}_{\odot}$. From the observations of the
components relative motion in the period 2000--2006, we conclude that GJ 900 is
a hierarchical triple star with the possible orbital periods
P$_{A-BC}$$\approx$80 yrs and P$_{BC}$$\approx$20 yrs. An analysis of the 2MASS
images of the region around GJ 900 leads us to suggest that the system can
include other very-low-mass components.


title: Probability Distributions in Complex Systems

abstract:
  We review briefly the concepts underlying complex systems and probability
distributions. The later are often taken as the first quantitative
characteristics of complex systems, allowing one to detect the possible
occurrence of regularities providing a step toward defining a classification of
the different levels of organization (the ``universality classes''). A rapid
survey covers the Gaussian law, the power law and the stretched exponential
distributions. The fascination for power laws is then explained, starting from
the statistical physics approach to critical phenomena, out-of-equilibrium
phase transitions, self-organized criticality, and ending with a large but not
exhaustive list of mechanisms leading to power law distributions. A check-list
for testing and qualifying a power law distribution from your data is described
in 7 steps. This essay enlarges the description of distributions by proposing
that ``kings'', i.e., events even beyond the extrapolation of the power law
tail, may reveal an information which is complementary and perhaps sometimes
even more important than the power law distribution. We conclude a list of
future directions.


title:
Generalized information theoretic measure to discern the quantumness of
  correlations

abstract:
  A novel measure, quantumness of correlations is introduced here for bipartite
states, by incorporating the required measurement scheme crucial in defining
any such quantity. Quantumness coincides with the previously proposed measures
in special cases and it vanishes for separable states - a feature not captured
by the measures proposed earlier. It is found that an optimal generalized
measurement on one of the parts leaves the overall state in its closest
separable form, which shares the same marginal for the other part, implying
that quantumness is non-zero for all entangled bipartite states and it serves
as an upper bound to the relative entropy of entanglement.


title:
The single-particle density matrix and the momentum distribution of dark
  "solitons" in a Tonks-Girardeau gas

abstract:
  We study the reduced single-particle density matrix (RSPDM), the momentum
distribution, natural orbitals and their occupancies, of dark "soliton" (DS)
states in a Tonks-Girardeau gas. DS states are specially tailored excited
many-body eigenstates, which have a dark solitonic notch in their
single-particle density. The momentum distribution of DS states has a
characteristic shape with two sharp spikes. We find that the two spikes arise
due to the high degree of correlation observed within the RSPDM between the
mirror points ($x$ and $-x$) with respect to the dark notch at $x=0$; the
correlations oscillate rather than decay as the points $x$ and $-x$ are being
separated.


title: Mechanical measurement of equilibrium spin currents in the Rashba medium

abstract:
  We demonstrate that an equilibrium spin current in a 2D electron gas with
Rashba spin-orbit interaction (Rashba medium) results in a mechanical torque on
a substrate near an edge of the medium. If the substrate is a cantilever, the
mechanical torque displaces the free end of the cantilever. The effect can be
enhanced and tuned by a magnetic field. Observation of this displacement would
be an effective method to prove existence of equilibrium spin currents. The
analysis of edges of the Rashba medium demonstrates the existence of localized
edge states. They form a 1D continuum of states. This suggests a new type of
quantum wire: spin-orbit quantum wire.


title: eta Chameleontis: abnormal initial mass function or dynamical evolution?

abstract:
  Eta Chamaeleontis is a unique young (~9 Myr) association with 18 systems
concentrated in a radius of ~35 arcmin, i.e. 1pc at the cluster distance of
97pc. No other members have been found up to 1.5 degrees from the cluster
centre. The cluster mass function is consistent with the IMF of other rich
young open clusters in the higher mass range but shows a clear deficit of low
mass stars and brown dwarfs with no objects below 0.1Msun. The aim of this
paper is to test whether this peculiar mass function could result from
dynamical evolution despite the young age of the cluster. We performed N-body
numerical calculations starting with a log-normal IMF and different initial
conditions in terms of number of systems and cluster radius using the code
NBODY3. We simulated the cluster dynamical evolution over 10 Myr and compared
the results to the observations. We found that it is possible to reproduce eta
Cha when starting with a very compact configuration (with Ninit=40 and
R0=0.005pc) which suggests that the IMF of the association might not be
abnormal. The high initial density might also explain the deficit of wide
binaries that is observed in the cluster.


title:
Observational constraints on the braneworld model with brane-bulk energy
  exchange

abstract:
  We investigate the viability of the braneworld model with energy exchange
between the brane and bulk, by using the most recent observational data related
to the background evolution. We show that this energy exchange behaves like a
source of dark energy and can alter the profile of the cosmic expansion. The
new Supernova Type Ia (SNIa) Gold sample, Supernova Legacy Survey (SNLS) data,
the position of the acoustic peak at the last scattering surface from the
Wilkinson Microwave Anisotropy Probe (WMAP) observations and the baryon
acoustic oscillation peak found in the Sloan Digital Sky Survey (SDSS) are used
to constrain the free parameters of this model. To infer its consistency with
the age of the Universe, we compare the age of old cosmological objects with
what computed using the best fit values for the model parameters. At 68% level
of confidence, the combination of Gold sample SNIa, Cosmic Microwave Background
(CMB) shift parameter and SDSS databases provide
$\Omega_m=0.29_{-0.02}^{+0.03}$, $\Omega_{A}=-0.71_{-0.03}^{+0.03}$ and
$\mu=-0.40_{-0.26}^{+0.28}$, hence a spatially flat Universe with
$\Omega_K=0.00_{-0.04}^{+0.04}$. The same combination with SNLS supernova
observation give $\Omega_m=0.27_{-0.02}^{+0.02}$,
$\Omega_{A}=-0.74_{-0.02}^{+0.04}$ and $\mu=0.00_{-0.30}^{+0.30}$ consequently
provides a spatially flat Universe $\Omega_K=-0.01_{-0.03}^{+0.04}$. These
results obviously seem to be compatible with the most recent WMAP results
indicating a flat Universe.


title: uvby--beta photoelectric photometry of NGC 7063

abstract:
  From uvby photometry of 75 stars in the direction of NGC 7063 we were able to
determine membership of some stars and fix the distance (722 +- 105 pc), log
age (of 8.146) and reddening (E(b-y) = 0.091 +- 0.039 mag) for the cluster.


title:
Influence of spin filtering and spin mixing on the subgap structure of
  I-V characteristics in superconducting quantum point contact

abstract:
  The effect of spin filtering and spin mixing on the dc electric current for
voltage biased magnetic quantum point contact with superconducting leads is
theoretically studied. The I-V characteristics are calculated for the whole
range of spin filtering and spin mixing parameters. It is found that with
increasing of spin filtering the subharmonic step structure of the dc electric
current, typical for low-transparency junction and junction without
considerable spin filtering qualitatively changes. In the lower voltage region
and for small enough spin mixing the peak structure arises. When spin mixing
increases the peak subgap structure evolves to the step structure. The voltages
where subharmonic gap features are located are found to be sensitive to the
value of spin filtering. The positions of peaks and steps are calculated
analytically and the evolution of the subgap structure from well-known tunnel
limit to the large spin filtering case is explained in terms of multiple
Andreev reflection (MAR) processes. In particular, it is found that for large
spin filtering the subgap feature at $eV_k$ arises from $2k^{\rm th}$ and
$(2k\pm 1)^{\rm th}$ order MAR processes, while in the tunnel limit the step at
$eV_n$ is known to result from $n^{\rm th}$ order MAR process.


title: Saturation model in the non-Glauber approach

abstract:
  In this paper a new saturation model is presented. This model is based on the
theoretical solution for the generating functional, and it is quite different
and not more complicated than the Glauber-like approach used before. The model
describes the structure function F_{2} of the proton, as well as the
diffractive structure function F_{2}^{D}. We show the difference between our
model, and the eikonal approach by calculating the multiplicity distribution,
using the AGK cutting rules strategy.


title:
On influence of experimental resolution on the statistical significance
  of a signal: implication for pentaquark searches

abstract:
  An analytical relationship between the statistical significance of an
observed signal and the signal width in case of a large background was
obtained. It can help to explain why high-energy experiments may have different
conclusions on the existence of new particles. We illustrate our approach using
the experimental data on searches for the Theta+(1530) pentaquark state. The
obtained relationship is also useful for planning of future experiments
designed to search for signals of new particles in invariant-mass
distributions.


title:
Deformation Quantization of Odd Dimensional anti-de Sitter Spaces as
  Contact Manifolds

abstract:
  We quantize odd dimensional anti-de Sitter spaces by applying the method of
deforming contact manifolds proposed by Rajeev. The construction in the present
paper consists of the identification of the odd dimensional anti-de Sitter
space as a hypersurface of contact type and the subsequent use of
'symplectization' principle. We also show that this construction generalizes to
any odd dimensional hypersurface which can be represented as a nonzero level
set of a homogenous function.


title:
Chiral Symmetry of Double-Walled Carbon Nanotubes detected in
  First-principles Optical Absorption Spectra

abstract:
  The linear polarizability absorption spectra of the double-walled carbon
nanotubes (DWNTs) have been calculated by using the tight-binding (TB) model
and sum-over-state (SOS) method, supplemented by the first principles CASTEP
calculations. It is found that the chiral symmetries of both outer and inner
tubes in the DWNTs can always be identified distinctly by the characteristic
peaks in the absorption spectra of the DWNTs, no matter what kind of the outer
tube is, offering a powerful experimental tool to measure precisely the chiral
angle of the inner tube of a DWNT.


title:
Photometry and astrometry of SS Leo Minoris during the 2006 October
  superoutburst

abstract:
  We report unfiltered CCD observations of the first confirmed superoutburst of
the SU UMa-type dwarf nova SS LMi in October 2006. From a quiescent magnitude
of around 21.7 it rose to 16.2, an outburst amplitude of about 5.5 magnitudes.
It declined at 0.17 mag/d for 5 days before slowing to 0.11 mag/d for a further
3 days. The light curve revealed common superhumps with a peak-to-peak
amplitude of 0.3 magnitude, which decayed and then re-grew concurrently with
the change in decline rate. These were followed by a phase-changing transition
to late superhumps. Analysis of these observations has revealed evidence for an
orbital period of 0.05572(19) d and a common superhump period of 0.05664(2) d,
giving a fractional superhump period excess of 0.017(5). From astrometry of SS
LMi in outburst we have established for the first time its correct position as
RA 10h 34m 05.85(1)s, Dec +31deg 08m 00.00(18)s (J2000). The position commonly
given for SS LMi is that of a nearby star.


title: Reduction of static field equation of Faddeev model

abstract:
  A method to solve the static field equation of the Faddeev model is
presented. For an special combination of the concerned field, we adopt a form
which is compatible with the field equation and involves two arbitrary complex
functions. As a result, the static field equation is reduced to a set of first
order partial differential equations.


title: Breakdown of chiral expansion for parton distributions

abstract:
  In the framework of the chiral perturbation theory we computed two- and
three-loop corrections to the pion parton distributions which posses
$\delta$-function singularities at x->0. This calculation explicitly
demonstrates that in the region of small x ~ mpi^2/(4 pi F)^2 standard ChPT
breaks down and one needs resummation of all orders. We give an example of such
resummation.


title: Stabilization of the spatial oscillations of an elastic system model

abstract:
  A system of partial differential equations describing the spatial
oscillations of an Euler-Bernoulli beam with a tip mass is considered. The
linear system considered is actuated by two independent controls and separated
into a pair of differential equations in a Hilbert space. A feedback control
ensuring strong stability of the equilibrium in the sense of Lyapunov is
proposed. The proof of the main result is based on the theory of strongly
continuous semigroups.


title: Ultracold scattering processes in three-atomic helium systems

abstract:
  We review results on scattering observables for $^4$He--$^4$He$_2$ and
$^3$He--$^4$He$_2$ collisions. We also study the effect of varying the coupling
constant of the atom-atom interaction on the scattering length.


title:
Linear and nonlinear low frequency electrodynamics of the surface
  superconducting states in an yttrium hexaboride a single crystal

abstract:
  We report the low-frequency and tunneling studies of yttrium hexaboride
single crystal. Ac susceptibility at frequencies 10 - 1500 Hz has been measured
in parallel to the crystal surface DC felds, H0. We found that in the DC feld
H0 > Hc2 DC magnetic moment completely disappears while the ac response
exhibited the presence of superconductivity at the surface. Increasing of the
DC field from Hc2 revealed the enlarging of losses with a maximum in the feld
between Hc2 and Hc3. Losses at the maximum were considerably larger than in the
mixed and in the normal states. The value of the DC field, where loss peak was
observed, depends on the amplitude and frequency of the ac feld. Close to Tc
this peak shifts below Hc2 which showed the coexistence of surface
superconducting states and Abrikosov vortices. We observed a logarithmic
frequency dependence of the in-phase component of the susceptibility. Such
frequency dispersion of the inphase component resembles the response of
spin-glass systems, but the out-of-phase component also exhibited frequency
dispersion that is not a known feature of the classic spin-glass response.
Analysis of the experimental data with Kramers-Kronig relations showed the
possible existence of the loss peak at very low frequencies (< 5 Hz). We found
that the amplitude of the third harmonic was not a cubic function of the ac
amplitude even at considerably weak ac felds. This does not leave any room for
treating the nonlinear effects on the basis of perturbation theory. We show
that the conception of surface vortices or surface critical currents could not
adequately describe the existing experimental data. Consideration of a model of
slow relaxing nonequilibrium order parameter permits one to explain the partial
shielding and losses of weak ac field for H0 > Hc2.


title:
Light-driven liquid crystalline nonlinear oscillator under optical
  periodic forcing

abstract:
  An all-optically driven strategy to govern a liquid crystalline collective
molecular nonlinear oscillator is discussed. It does not require external
feedbacks of any kind while the oscillator and a time-depending perturbation
both are sustained by incident light. Various dynamical regimes such as
frequency -locked, quasiperiodic, forced and chaotic are observed in agreement
with a theoretical approach developed in the limit of the plane wave
approximation.


title:
Dynamical localization of a particle coupled to a two-level systems
  thermal reservoir

abstract:
  Using the functional-integral method, we investigate the effect of a
two-level systems thermal reservoir on the single particle dynamics. We find
that at low temperatures, within the sub-ohmic regime, the particle becomes
{}``dynamically'' localized at long times due to an effective potential
generated by the particle-reservoir interaction. This behavior is different
from the one obtained for the usual bath of harmonic oscillators and is
fundamentally related with the non-Markovian character of the dissipative
process.


title: Anomalous thermal expansion in $\alpha$-titanium

abstract:
  We provide a complete quantitative explanation for the anisotropic thermal
expansion of hcp Ti at low temperature. The observed negative thermal expansion
along the c-axis is reproduced theoretically by means of a parameter free
theory which involves both the electron and phonon contributions to the free
energy. The thermal expansion of titanium is calculated and found to be
negative along the c-axis for temperatures below $\sim$ 170 K, in good
agreement with observations. We have identified a saddle-point Van Hove
singularity near the Fermi level as the main reason for the anisotropic thermal
expansion in $\alpha-$titanium.


title: Detection of massive multi-particle beams by two-particle ionization

abstract:
  Multi-photon absorption is a well-known phenomenon. With atom lasers a
similar process could take place for massive particles, the ionization of an
atom or molecule by the successive interaction with various particles. This
process would lead to multi-particle detection events for incident
multi-particle beams. We show that two-particle detections would introduce a
correction (proportional to the fourth power of the wavefunction modulus) to
the usual one-particle detection probability (only proportional to the second
power).


title: Double beta decay: experiments and theory review

abstract:
  Neutrinoless double beta decay is one of the most powerful tools to set the
neutrino mass absolute scale and establish whether the neutrino is a Majorana
particle. After a summary of the neutrinoless double beta decay phenomenology,
the present status of the experimental search for this rare decay is reported
and the prospects for next generation experiments are reviewed.


title: The Killing spinor equation with higher order potentials

abstract:
  Let (M^n,g) be a Riemannian spin manifold. The basic equations in
supergravity models of type IIa string theory with 4-form flux involve a 3-form
T, a 4-form F, a spinorial covariant derivative \nabla depending on \nabla^g,
T, F, and a \nabla-parallel spinor field \Psi. We classify and construct many
explicit families of solutions to this system of spinorial field equations by
means of non-integrable special geometries. The latter include \alpha-Sasakian
structures in dimensions 5 and 7, almost Hermitian structures in dimension 6
and cocalibrated G_2-structures in dimension 7. We show that there are several
examples also satisfying an additional constraint for the energy-momentum
tensor.


title: HCOOH high resolution spectroscopy in the 9.18$\mu$m region

abstract:
  We report on higly accurate absolute frequency measurement against a
femtosecond frequency comb of 6 saturated absorption lines of formic acid
(HCOOH) with an accuracy of 1 kHz. We also report the frequency measurement of
17 other lines with an accuracy of 2 kHz. Those lines are in quasi coincidence
with the 9R(36) to 9R(42) CO$_2$ laser emission lines and are probed either by
a CO$_2$ or a widely tunable quantum cascade laser phase locked to a master
CO$_2$ laser. The relative stability of two HCOOH stabilized lasers is
characterized by a relative Allan deviation of 4.5 10$^{-12}$ $\tau^{-1/2}$.
They give suitable frequency references for H$_2^+$ Doppler free two-photon
spectroscopy.


title: Hypernovae and their Gamma-Ray Bursts Connection

abstract:
  The connection between long Gamma Ray Bursts (GRBs) and Supernovae (SNe),
have been established through the well observed cases of GRB980425/SN 1998bw,
GRB030329/SN 2003dh and GRB031203/SN 2003lw. These events can be explained as
the prompt collapse to a black hole (BH) of the core of a massive star (M ~ 40
Msun) that had lost its outer hydrogen and helium envelopes. All these SNe
exhibited strong oxygen lines, and their energies were much larger than those
of typical SNe, thus these SNe are called Hypernovae (HNe). The case of SN
2006aj/GRB060218 appears different: the GRB was weak and soft (an X-Ray Flash,
XRF); the SN is dimmer and has very weak oxygen lines. The explosion energy of
SN 2006aj was smaller, as was the ejected mass. In our model, the progenitor
star had a smaller mass than other GRB/SNe (M ~ 20 Msun), suggesting that a
neutron star (NS) rather than a black hole was formed. If the nascent neutron
star was strongly magnetized (a so-called magnetar) and rapidly spinning, it
may launch a weak GRB or an XRF. The final fate of 20-30 Msun stars show
interesting variety, as seen in the very peculiar Type Ib/c SN 2005bf. This
mass range corresponds to the NS to BH transition. We also compare the
nucleosynthesis feature of HNe with the metal-poor stars and suggest the
Hypernova-First Star connection.


title: A remark on invariants for C*-algebras of stable rank one

abstract:
  It is shown that, for a C*-algebra of stable rank one (i.e., in which the
invertible elements are dense), two well-known isomorphism invariants, the
Cuntz semigroup and the Thomsen semigroup, contain the same information. More
precisely, these two invariants, viewed appropiately, determine each other in a
natural way.


title: On some properties of travelling water waves with vorticity

abstract:
  We prove that for a large class of vorticity functions the crest of a
corresponding travelling water wave is necessarily a point of maximal
horizontal velocity. We also show that for waves with nonpositive vorticity the
pressure in the flow is everywhere larger than the atmospheric pressure. A
related a priori estimate for waves with nonnegative vorticity is also given.


title:
Impact picture for the analyzing power $A_N$ in very forward $pp$
  elastic scattering

abstract:
  In the framework of the impact picture we compute the analyzing power $A_N$
for $pp$ elastic scattering at high energy and in the very forward direction.
We consider the full set of Coulomb amplitudes and show that the interference
between the hadronic non-flip amplitude and the single-flip Coulomb amplitude
is sufficient to obtain a good agreement with the present experimental data.
This leads us to conclude that the single-flip hadronic amplitude is small in
this low momentum transfer region and it strongly suggests that this process
can be used as an absolute polarimeter at the BNL-RHIC $pp$ collider.


title: "Disproof of Bell's Theorem" : more critics

abstract:
  In a series of recent papers (quant-ph/0703179, quant-ph/0703244,
arXiv:0707.1333) Joy Christian claims to have "disproved Bell's theorem".
Though his work is certainly intellectually stimulating, we argue below that
his main claim is unwarranted.


title:
On the existence of extreme waves and the Stokes conjecture with
  vorticity

abstract:
  This is a study of singular solutions of the problem of traveling gravity
water waves on flows with vorticity. We show that, for a certain class of
vorticity functions, a sequence of regular waves converges to an extreme wave
with stagnation points at its crests. We also show that, for any vorticity
function, the profile of an extreme wave must have either a corner of
$120^\circ$ or a horizontal tangent at any stagnation point about which it is
supposed symmetric. Moreover, the profile necessarily has a corner of
$120^\circ$ if the vorticity is nonnegative near the free surface.


title:
On the evolution of eccentric and inclined protoplanets embedded in
  protoplanetary disks

abstract:
  Young planets embedded in their protoplanetary disk interact gravitationally
with it leading to energy and angular momentum exchange. This interaction
determines the evolution of the planet through changes to the orbital
parameters. We investigate changes in the orbital elements of a 20 Earth--mass
planet due to the torques from the disk. We focus on the non-linear evolution
of initially non-vanishing eccentricity $e$ and/or inclination $i$. We treat
the disk as a two- or three-dimensional viscous fluid and perform
hydrodynamical simulations with an embedded planet. We find rapid exponential
decay of the planet orbital eccentricity and inclination for small initial
values of $e$ and $i$, in agreement with linear theory. For larger values of $e
> 0.1$ the decay time increases and the decay rate scales as $\dot{e} \propto
e^{-2}$, consistent with existing theoretical models. For large inclinations
($i$ > 6 deg) the inclination decay rate shows an identical scaling $di/dt
\propto i^{-2}$. We find an interesting dependence of the migration on the
eccentricity. In a disk with aspect ratio $H/r=0.05$ the migration rate is
enhanced for small non-zero eccentricities ($e < 0.1$), while for larger values
we see a significant reduction by a factor of $\sim 4$. We find no indication
for a reversal of the migration for large $e$, although the torque experienced
by the planet becomes positive when $e \simeq 0.3$. This inward migration is
caused by the persisting energy loss of the planet.
  For non gap forming planets, eccentricity and inclination damping occurs on a
time scale that is very much shorter than the migration time scale. The results
of non linear hydrodynamic simulations are in very good agreement with linear
theory for small $e$ and $i$.


title:
Thermodynamical Equilibrium of Vortices in the Isotropic Bidimensional
  Kac Rotator

abstract:
  We consider here the problem of extrema for the Kac functional with long
range, ferromagnetic interaction, and vorticity conditions at infinity which
make it not weakly closed. Using a gradient-flow dynamics, we investigate local
minima, showing strong analogies with the Ginzburg-Landau functional in
infinite volume.


title:
Degeneracy study of the forward kinematics of planar 3-RPR parallel
  manipulators

abstract:
  This paper investigates two situations in which the forward kinematics of
planar 3-RPR parallel manipulators degenerates. These situations have not been
addressed before. The first degeneracy arises when the three input joint
variables r1, r2 and r3 satisfy a certain relationship. This degeneracy yields
a double root of the characteristic polynomial in t, which could be erroneously
interpreted as two coalesce assembly modes. But, unlike what arises in
non-degenerate cases, this double root yields two sets of solutions for the
position coordinates (x, y) of the platform. In the second situation, we show
that the forward kinematics degenerates over the whole joint space if the base
and platform triangles are congruent and the platform triangle is rotated by
180 deg about one of its sides. For these "degenerate" manipulators, which are
defined here for the first time, the forward kinematics is reduced to the
solution of a 3rd-degree polynomial and a quadratics in sequence. Such
manipulators constitute, in turn, a new family of analytic planar manipulators
that would be more suitable for industrial applications.


title: Kinematic Analysis of a Family of 3R Manipulators

abstract:
  The workspace topologies of a family of 3-revolute (3R) positioning
manipulators are enumerated. The workspace is characterized in a half-cross
section by the singular curves. The workspace topology is defined by the number
of cusps that appear on these singular curves. The design parameters space is
shown to be divided into five domains where all manipulators have the same
number of cusps. Each separating surface is given as an explicit expression in
the DH-parameters. As an application of this work, we provide a necessary and
sufficient condition for a 3R orthogonal manipulator to be cuspidal, i.e. to
change posture without meeting a singularity. This condition is set as an
explicit expression in the DH parameters.


title:
The Computation of All 4R Serial Spherical Wrists With an Isotropic
  Architecture

abstract:
  A spherical wrist of the serial type with n revolute (R) joints is said to be
isotropic if it can attain a posture whereby the singular values of its
Jacobian matrix are all equal to sqrt(n/3). What isotropy brings about is
robustness to manufacturing, assembly, and measurement errors, thereby
guaranteeing a maximum orientation accuracy. In this paper we investigate the
existence of redundant isotropic architectures, which should add to the
dexterity of the wrist under design by virtue of its extra degree of freedom.
The problem formulation, for, leads to a system of eight quadratic equations
with eight unknowns. The Bezout number of this system is thus 2^8=256, its BKK
bound being 192. However, the actual number of solutions is shown to be 32. We
list all solutions of the foregoing algebraic problem. All these solutions are
real, but distinct solutions do not necessarily lead to distinct manipulators.
Upon discarding those algebraic solutions that yield no new wrists, we end up
with exactly eight distinct architectures, the eight corresponding manipulators
being displayed at their isotropic postures.


title:
Ab initio relativistic many-body calculation of hyperfine splitting of
  ^{113}Cd^+

abstract:
  This work presents accurate ab initio determination of the hyperfine
splitting for the ground state and few low-lying excited states of 113Cd+;
important candidates for the frequency standard in the microwave region, using
coupled-cluster theory (CC) in the relativistic framework. The calculated
hyperfine splitting are well in agreement with recent experimental results. We
have also carried out the lifetimes of the 5p2P1=2 and 5p2P3=2 states, which
are in well agreement with recent experimental result (Moehring et al., PRA 73
023413, 2006). The roles of different electron correlation effects in the
determination of these quantities are discussed and their contributions are
presented in the CC terms.


title: EAS Longitudinal Development and the Knee

abstract:
  It is shown that Extensive Air Shower (EAS) longitudinal development has a
critical point where an equilibrium between the main hadronic component and the
secondary electromagnetic one exhibits a brake. This results in a change of
slope in quasi-power law function $N_{e}(Eo)$. The latter leads to a knee in
the EAS size spectrum at primary energy of about 100 TeV/nucleon. Many
``strange'' experimental results can be successfully explained in the frames of
current approach.


title:
Backward scattering of low-energy antiprotons by highly charged and
  neutral uranium: Coulomb glory

abstract:
  Collisions of antiprotons with He-, Ne-, Ni-like, bare, and neutral uranium
are studied theoretically for scattering angles close to 180$^{\circ}$ and
antiproton energies with the interval 100 eV -- 10 keV. We investigate the
Coulomb glory effect which is caused by a screening of the Coulomb potential of
the nucleus and results in a prominent maximum of the differential cross
section in the backward direction at some energies of the incident particle. We
found that for larger numbers of electrons in the ion the effect becomes more
pronounced and shifts to higher energies of the antiproton. On the other hand,
a maximum of the differential cross section in the backward direction can also
be found in the scattering of antiprotons on a bare uranium nucleus. The latter
case can be regarded as a manifestation of the screening property of the
vacuum-polarization potential in non-relativistic collisions of heavy
particles.


title: Nondecoupling of Heavy Fermions and a Special Yukawa Texture

abstract:
  Talk based on work entitled ``Yukawa textures, new physics and
nondecoupling,'' done in collaboration with G. C. Branco and J. I.
Silva-Marcos, arXiv:hep-ph/0612252, to appear in Phys. Rev. D. In this work we
pointed out that New Physics can play an important r\^ ole in rescuing some of
the Yukawa texture zero ans\" atze which would otherwise be eliminated by the
recent, more precise measurements of $V_{CKM}$. We have shown that the presence
of an isosinglet vector-like quark which mixes with standard quarks, can render
viable a particularly interesting four texture zero Yukawa ansatz. The crucial
point is the nondecoupling of the effects of the isosinglet quark, even for
arbitrary large values of its mass.


title:
State-dependent diffusion: thermodynamic consistency and its path
  integral formulation

abstract:
  The friction coefficient of a particle can depend on its position as it does
when the particle is near a wall. We formulate the dynamics of particles with
such state-dependent friction coefficients in terms of a general Langevin
equation with multiplicative noise, whose evaluation requires the introduction
of specific rules. Two common conventions, the Ito and the Stratonovich,
provide alternative rules for evaluation of the noise, but other conventions
are possible. We show the requirement that a particle's distribution function
approach the Boltzmann distribution at long times dictates that a drift term
must be added to the Langevin equation. This drift term is proportional to the
derivative of the diffusion coefficient times a factor that depends on the
convention used to define the multiplicative noise. We explore the consequences
of this result in a number examples with spatially varying diffusion
coefficients. We also derive path integral representations for arbitrary
interpretation of the noise, and use it in a perturbative study of correlations
in a simple system.


title:
Dynamics of bacterial flow: Emergence of spatiotemporal coherent
  structures

abstract:
  We propose a simple model of self-propelled particles to show that coherent
structures, such as jets and swirls, can arise from a plausible microscopic
mechanisms: (i) the elongated shape of the self-propelled particles with (ii)
the hardcore interactions among them. We demonstrate via computer simulation
that these coherent structures, which emerge at sufficiently high densities of
particles, have characteristics that are similar to those observed in recent
experiments in bacteria baths.


title:
Probability Bracket Notation: Probability Space, Conditional Expectation
  and Introductory Martingales

abstract:
  In this paper, we continue to explore the consistence and usability of
Probability Bracket Notation (PBN) proposed in our previous articles. After a
brief review of PBN with dimensional analysis, we investigate probability
spaces in terms of PBN by introducing probability spaces associated with random
variables (R.V) or associated with stochastic processes (S.P). Next, we express
several important properties of conditional expectation (CE) and some their
proofs in PBN. Then, we introduce martingales based on sequence of R.V or based
on filtration in PBN. In the process, we see PBN can be used to investigate
some probability problems, which otherwise might need explicit usage of Measure
theory. Whenever applicable, we use dimensional analysis to validate our
formulas and use graphs for visualization of concepts in PBN. We hope this
study shows that PBN, stimulated by and adapted from Dirac notation in Quantum
Mechanics (QM), may have the potential to be a useful tool in probability
modeling, at least for those who are already familiar with Dirac notation in
QM.


title: Spectropolarimetry of the Type Ib/c SN 2005bf

abstract:
  We present spectropolarimetric observations of the peculiar Type Ib/c SN
2005bf, in MCG+00-27-005, from 3600-8550\AA. The SN was observed on 2005 April
30.9, 18 days after the first B-band light-curve maximum and 6 days before the
second B-band light-curve maximum. The degree of the Interstellar Polarization,
determined from depolarized emission lines in the spectrum, is found to be
large with $p_{max}(ISP)=1.6%$ and $\theta(ISP)=149$\fdg$7\pm4.0$, but this may
be an upper limit on the real value of the ISP. After ISP subtraction,
significant polarization is observed over large wavelength regions, indicating
a significant degree of global asymmetry, $\gtrsim 10%$. Polarizations of 3.5%
and 4% are observed for absorption components of Ca II H&K and IR triplet, and
1.3% for He I 5876\AA and Fe II. On the $Q-U$ plane clear velocity-dependent
loop structure is observed for the He I 5876\AA line, suggestive of departures
from an axial symmetry and possible clumping of the SN ejecta. Weak High
Velocity components of $\mathrm{H\alpha}$, $\mathrm{H\beta}$ and
$\mathrm{H\gamma}$ are observed, with velocities of -15 000\kms. The low degree
of polarization observed at H$\beta$ suggests that the polarization observed
for the other Balmer lines ($\sim 0.4%$ above the background polarization) may
rather be due to blending of $\mathrm{H\alpha}$ and $\mathrm{H\gamma}$ with
polarized Si II and Fe II lines, respectively. We suggest a model in which a
jet of material, that is rich in $\mathrm{^{56}Ni}$, has penetrated the C-O
core, but not the He mantle. The jet axis is tilted with respect to the axis of
the photosphere. This accounts for the lack of significant polarization of O I
7774\AA, the delayed excitation and, hence, observability of He I and,
potentially, the varied geometries of He and Ca.


title:
A design oriented study for 3R Orthogonal Manipulators With Geometric
  Simplifications

abstract:
  This paper proposes a method to calculate the largest Regular Dextrous
Workspace (RDW) of some types of three-revolute orthogonal manipulators that
have at least one of their DH parameters equal to zero. Then a new performance
index based on the RDW is introduced, the isocontours of this index are plotted
in the parameter space of the interesting types of manipulators and finally an
inspection of the domains of the parameter spaces is conducted in order to
identify the better manipulator architectures. The RDW is a part of the
workspace whose shape is regular (cube, cylinder) and the performances
(conditioning index) are bounded inside. The groups of 3R orthogonal
manipulators studied have interesting kinematic properties such as, a
well-connected workspace that is fully reachable with four inverse kinematic
solutions and that does not contain any void. This study is of high interest
for the design of alternative manipulator geometries.


title:
Saddle-point van Hove singularity and the phase diagram of high-Tc
  cuprates

abstract:
  We examine the generic phase behavior of high-Tc cuprate superconductors in
terms a universal van Hove singularity in the strongly overdoped region. Using
a rigid ARPES-derived dispersion we solve the BCS gap equation and show that
the pairing interaction or pairing energy cutoff must be a rapidly declining
function of doping. This result is prejudicial to a phonon-based pairing
interaction and more consistent with a magnetic or magnetically enhanced
interaction.


title: The Eruption from a Sigmoidal Solar Active Region on 2005 May 13

abstract:
  This paper presents a multiwavelength study of the M8.0 flare and its
associated fast halo CME that originated from a bipolar active region NOAA
10759 on 2005 May 13. The source active region has a conspicuous sigmoid
structure at TRACE 171 A channel as well as in the SXI soft X-ray images, and
we mainly concern ourselves with the detailed process of the sigmoid eruption
as evidenced by the multiwavelength data ranging from Halpha, WL, EUV/UV,
radio, and hard X-rays (HXRs). The most important finding is that the flare
brightening starts in the core of the active region earlier than that of the
rising motion of the flux rope. This timing clearly addresses one of the main
issues in the magnetic eruption onset of sigmoid, namely, whether the eruption
is initiated by an internal tether-cutting to allow the flux rope to rise
upward or a flux rope rises due to a loss of equilibrium to later induce tether
cutting below it. Our high time cadence SXI and Halpha data shows that the
first scenario is relevant to this eruption. As other major findings, we have
the RHESSI HXR images showing a change of the HXR source from a confined
footpoint structure to an elongated ribbon-like structure after the flare
maximum, which we relate to the sigmoid-to-arcade evolution. Radio dynamic
spectrum shows a type II precursor that occurred at the time of expansion of
the sigmoid and a drifting pulsating structure in the flare rising phase in
HXR. Finally type II and III bursts are seen at the time of maximum HXR
emission, simultaneous with the maximum reconnection rate derived from the
flare ribbon motion in UV. We interpret these various observed properties with
the runaway tether-cutting model proposed by Moore et al. in 2001.


title: Etude Des Solutions Meromorphes D'Equations Differentielles

abstract:
  In this paper we shall study differential equations in the complex domain.
The method of indeterminate coefficients and the majorant method lead to a
proof of the existence and uniqueness of meromorphic solution of differential
equations. We discuss their connection with the concept of algebraic
integrability systems.


title:
Carrier Statistics and Quantum Capacitance of Graphene Sheets and
  Ribbons

abstract:
  In this work, fundamental results for carrier statistics in graphene
2-dimensional sheets and nanoscale ribbons are derived. Though the behavior of
intrinsic carrier densities in 2d graphene sheets is found to differ
drastically from traditional semiconductors, very narrow (sub-10 nm) ribbons
are found to be similar to traditional narrow-gap semiconductors. The quantum
capacitance, an important parameter in the electrostatic design of devices, is
derived for both 2d graphene sheets and nanoribbons.


title: Dissipative Dynamics of Matter Wave Soliton in Nonlinear Optical Lattice

abstract:
  Dynamics and stability of solitons in two-dimensional (2D) Bose-Einstein
condensates (BEC), with low-dimensional (1D) conservative plus dissipative
nonlinear optical lattices are investigated. In the case of focusing media
(with attractive atomic systems) the collapse of the wave packet is arrested by
the dissipative periodic nonlinearity. The adiabatic variation of the
background scattering length leads to metastable matter-wave solitons.
  When the atom feeding mechanism is used, a dissipative soliton can exist in
focusing 2D media with 1D periodic nonlinearity. In the defocusing media
(repulsive BEC case) with harmonic trap in one dimension and one dimensional
nonlinear optical lattice in other direction, the stable soliton can exist.
This prediction of variational approach is confirmed by the full numerical
simulation of 2D Gross-Pitaevskii equation.


title:
Enhancement of Carrier Mobility in Semiconductor Nanostructures by
  Dielectric Engineering

abstract:
  We propose a technique for achieving large improvements in carrier mobilities
in 2- and 1-dimensional semiconductor nanostructures by modifying their
dielectric environments. We show that by coating the nanostructures with
high-$\kappa$ dielectrics, scattering from Coulombic impurities can be strongly
damped. Though screening is also weakened, the damping of Coulombic scattering
is much larger, and the resulting improvement in mobilities of carriers can be
as much as an order of magnitude for thin 2D semiconductor membranes, and more
for semiconductor nanowires.


title:
Some phenomenological considerations on the nuclear collisions at high
  energies

abstract:
  We present some results obtained by applying the chaos theory on the
numerical study of one threedimensional, relativistic, many-body quark system.
The asymptotic freedom property is introduced by employing a harmonic term in
the bi-particle potential. In this context, we used also the outcome of a
semiclassical study, applied to the quark constituents of nucleons. Depending
on the initial temperature parameter, the system can evolve toward an
oscillating or an expansion regime. It is important to notice also a transition
region, characterized by a partial fragmentation (higher degree of order). This
effect can be observed near the critical temperature and is related to the
partial overcoming of the potential barrier (corresponding to the farthest
particles from the system). The degree of fragmentation is defined on the
Shannon entropy basis and using the graphs theory. For analyzing the expansion
tendency of one relativistic many-body system, we employed also the virial
coefficient.


title: Fibered Correspondence

abstract:
  Base of fibered correspondence is arbitrary correspondence. Fibered
correspondence is interesting when we consider relationship between different
bundles. However composition of fibered correspondences may not always be
defined. Reduced fibered correspondence is defined only between fibers over the
same point of base. Reduced fibered correspondence in bundle is called 2-ary
fibered relation. We considered fibered equivalence and isomorphism theorem in
case of fibered morphisms.


title:
Generic initial ideals, graded Betti numbers and $k$-Lefschetz
  properties

abstract:
  We introduce the $k$-strong Lefschetz property ($k$-SLP) and the $k$-weak
Lefschetz property ($k$-WLP) for graded Artinian $K$-algebras, which are
generalizations of the Lefschetz properties. The main results obtained in this
paper are as follows:
  1. Let $I$ be a graded ideal of $R=K[x_1, x_2, x_3]$ whose quotient ring
$R/I$ has the SLP. Then the generic initial ideal of $I$ is the unique almost
revlex ideal with the same Hilbert function as $R/I$.
  2. Let $I$ be a graded ideal of $R=K[x_1, x_2, ..., x_n]$ whose quotient ring
$R/I$ has the $n$-SLP. Suppose that all $k$-th differences of the Hilbert
function of $R/I$ are quasi-symmetric. Then the generic initial ideal of $I$ is
the unique almost revlex ideal with the same Hilbert function as $R/I$.
  3. We give a sharp upper bound on the graded Betti numbers of Artinian
$K$-algebras with the $k$-WLP and a fixed Hilbert function.


title: The crystal commutor and Drinfeld's unitarized R-matrix

abstract:
  Drinfeld defined a unitarized R-matrix for any quantum group U_q(g). This
gives a commutor for the category of U_q(g) representations, making it into a
coboundary category. Henriques and Kamnitzer defined another commutor which
also gives U_q(g) representations the structure of a coboundary category. We
show that a particular case of Henriques and Kamnitzer's construction agrees
with Drinfeld's commutor. We then describe the action of Drinfeld's commutor on
a tensor product of two crystal bases, and explain the relation to the crystal
commutor.


title:
A Subaru Weak Lensing Survey I: Cluster Candidates and Spectroscopic
  Verification

abstract:
  We present the results of an ongoing weak lensing survey conducted with the
Subaru telescope whose initial goal is to locate and study the distribution of
shear-selected structures or halos. Using a Suprime-cam imaging survey spanning
21.82 square degree, we present a catalog of 100 candidate halos located from
lensing convergence maps. Our sample is reliably drawn from that subset of our
survey area, (totaling 16.72 square degree) uncontaminated by bright stars and
edge effects and limited at a convergence signal to noise ratio of 3.69. To
validate the sample detailed spectroscopic measures have been made for 26
candidates using the Subaru multi-object spectrograph, FOCAS. All are confirmed
as clusters of galaxies but two arise as the superposition of multiple clusters
viewed along the line of sight. Including data available in the literature and
an ongoing Keck spectroscopic campaign, a total of 41 halos now have reliable
redshifts. For one of our survey fields, the XMM LSS (Pierre et al. 2004)
field, we compare our lensing-selected halo catalog with its X-ray equivalent.
Of 15 halos detected in the XMM-LSS field, 10 match with published X-ray
selected clusters and a further 2 are newly-detected and spectroscopically
confirmed in this work. Although three halos have not yet been confirmed, the
high success rate within the XMM-LSS field (12/15) confirms that weak lensing
provides a reliable method for constructing cluster catalogs, irrespective of
the nature of the constituent galaxies or the intracluster medium.


title:
Two novel approaches for photometric redshift estimation based on SDSS
  and 2MASS databases

abstract:
  We investigate two training-set methods: support vector machines (SVMs) and
Kernel Regression (KR) for photometric redshift estimation with the data from
the Sloan Digital Sky Survey Data Release 5 and Two Micron All Sky Survey
databases. We probe the performances of SVMs and KR for different input
patterns. Our experiments show that the more parameters considered, the
accuracy doesn't always increase, and only when appropriate parameters chosen,
the accuracy can improve. Moreover for different approaches, the best input
pattern is different. With different parameters as input, the optimal bandwidth
is dissimilar for KR. The rms errors of photometric redshifts based on SVM and
KR methods are less than 0.03 and 0.02, respectively. Finally the strengths and
weaknesses of the two approaches are summarized. Compared to other methods of
estimating photometric redshifts, they show their superiorities, especially KR,
in terms of accuracy.


title: "Phase Diagram" of the Spin Hall Effect

abstract:
  We obtain analytic formulas for the frequency-dependent spin-Hall
conductivity of a two-dimensional electron gas (2DEG) in the presence of
impurities, linear spin-orbit Rashba interaction, and external magnetic field
perpendicular to the 2DEG. We show how different mechanisms (skew-scattering,
side-jump, and spin precession) can be brought in or out of focus by changing
controllable parameters such as frequency, magnetic field, and temperature. We
find, in particular, that the d.c. spin Hall conductivity vanishes in the
absence of a magnetic field, while a magnetic field restores the
skew-scattering and side-jump contributions proportionally to the ratio of
magnetic and Rashba fields.


title: On the Rapid Collapse and Evolution of Molecular Clouds

abstract:
  Stars generally form faster than the ambipolar diffusion time, suggesting
that several processes short circuit the delay and promote a rapid collapse.
These processes are considered here, including turbulence compression in the
outer parts of giant molecular cloud (GMC) cores and GMC envelopes, GMC core
formation in an initially supercritical state, and compression-induced
triggering in dispersing GMC envelopes. The classical issues related to star
formation timescales are addressed: high molecular fractions, low efficiencies,
long consumption times for CO and HCN, rapid GMC core disruption and the lack
of a stable core, long absolute but short relative timescales with accelerated
star formation, and the slow motions of protostars. We consider stimuli to
collapse from changes in the density dependence of the ionization fraction, the
cosmic ray ionization rate, and various dust properties at densities above
~10^5 cm^{-3}. We favor the standard model of subcritical GMC envelops and
suggest they would be long lived if not for disruption by rapid star formation
in GMC cores. The lifecycle of GMCs is illustrated by a spiral arm section in
the Hubble Heritage image of M51, showing GMC formation, star formation, GMC
disruption with lingering triggered star formation, and envelope dispersal.
There is no delay between spiral arm dustlanes and star formation; the
classical notion results from heavy extinction in the dust lane and triggered
star formation during cloud dispersal. Differences in the IMF for the different
modes of star formation are considered.


title: Zener double exchange from local valence fluctuations in magnetite

abstract:
  Magnetite (Fe$_{3}$O$_{4}$) is a mixed valent system where electronic
conductivity occurs on the B-site (octahedral) iron sublattice of the spinel
structure. Below $T_{V}=122$ K, a metal-insulator transition occurs which is
argued to arise from the charge ordering of 2+ and 3+ iron valences on the
B-sites (Verwey transition). Inelastic neutron scattering measurements show
that optical spin waves propagating on the B-site sublattice ($\sim$80 meV) are
shifted upwards in energy above $T_{V}$ due to the occurrence of B-B
ferromagnetic double exchange in the mixed valent metallic phase. The double
exchange interaction affects only spin waves of $\Delta_{5}$ symmetry, not all
modes, indicating that valence fluctuations are slow and the double exchange is
constrained by electron correlations above $T_{V}$.


title:
Nonlinear Thermal Properties of Three-Terminal Mesoscopic Dielectric
  Systems

abstract:
  This paper studies the thermal properties of three-terminal mesoscopic
dielectric systems in the nonlinear response regime at low temperature. For a
symmetric three-terminal system, when the temperature is finitely different
between the left and right thermal reservoirs, the temperature of the central
thermal reservoir is always higher than the averaging temperature of the
others. This nonlinear thermal phenomenon is also observed for asymmetric
three-terminal systems. At the end, a model of thermal rectification is
presented.


title:
The r-Process in Supersonic Neutrino-Driven Winds: The Roll of Wind
  Termination Shock

abstract:
  Recent hydrodynamic studies of core-collapse supernovae imply that the
neutrino-heated ejecta from a nascent neutron star develops to supersonic
outflows. These supersonic winds are influenced by the reverse shock from the
preceding supernova ejecta, forming the wind termination shock. We investigate
the effects of the termination shock in neutrino-driven winds and its roll on
the r-process. Supersonic outflows are calculated with a semi-analytic
neutrino-driven wind model. Subsequent termination-shocked, subsonic outflows
are obtained by applying the Rankine-Hugoniot relations. We find a couple of
effects that can be relevant for the r-process. First is the sudden slowdown of
the temperature decrease by the wind termination. Second is the entropy jump by
termination-shock heating, up to several 100NAk. Nucleosynthesis calculations
in the obtained winds are performed to examine these effects on the r-process.
We find that 1) the slowdown of the temperature decrease plays a decisive roll
to determine the r-process abundance curves. This is due to the strong
dependences of the nucleosynthetic path on the temperature during the r-process
freezeout phase. Our results suggest that only the termination-shocked winds
with relatively small shock radii (~500km) are relevant for the bulk of the
solar r-process abundances (A~100-180). The heaviest part in the solar
r-process curve (A~180-200), however, can be reproduced both in shocked and
unshocked winds. These results may help to constrain the mass range of
supernova progenitors relevant for the r-process. We find, on the other hand,
2) negligible roles of the entropy jump on the r-process. This is a consequence
that the sizable entropy increase takes place only at a large shock radius
(~10,000km) where the r-process has already ceased.


title:
On the First Law of Thermodynamics for (2+1) Dimensional Charged BTZ
  Black Hole and Charged de Sitter Space

abstract:
  In this paper we will show that using the cosmological constant as a new
thermodynamical state variable, the differential and integral mass formulas of
the first law of thermodynamics for asymptotic flat spacetimes can be extended
to (2+1) dimensional charged BTZ black holes and charged de Sitter space.


title: A Bayes method for a Bathtub Failure Rate via two $\mathbf{S}$-paths

abstract:
  A class of semi-parametric hazard/failure rates with a bathtub shape is of
interest. It does not only provide a great deal of flexibility over existing
parametric methods in the modeling aspect but also results in a closed and
tractable Bayes estimator for the bathtub-shaped failure rate (BFR). Such an
estimator is derived to be a finite sum over two $\mathbf{S}$-paths due to an
explicit posterior analysis in terms of two (conditionally independent)
$\mathbf{S}$-paths. These, newly discovered, explicit results can be proved to
be a Rao-Blackwellization of counterpart results in terms of partitions that
are readily available by a specialization of James (2005)'s work. We develop
both iterative and non-iterative computational procedures based on existing
efficient Monte Carlo methods for sampling one single $\mathbf{S}$-path.
Nmerical simulations are given to demonstrate the practicality and the
effectiveness of our methodology. Last but not least, two applications of the
proposed method are discussed, of which one is about a Bayesian test for
failure rates and the other is related to modeling with covariates.


title: Solar activity forecast with a dynamo model

abstract:
  Although systematic measurements of the solar polar magnetic field exist only
from mid 1970s, other proxies can be used to infer the polar field at earlier
times. The observational data indicate a strong correlation between the polar
field at a sunspot minimum and the strength of the next cycle, although the
strength of the cycle is not correlated well with the polar field produced at
its end. This suggests that the Babcock Leighton mechanism of poloidal field
generation from decaying sunspots involves randomness, whereas the other
aspects of the dynamo process must be reasonably ordered and deterministic.
Only if the magnetic diffusivity within the convection zone is assumed to be
high, we can explain the correlation between the polar field at a minimum and
the next cycle. We give several independent arguments that the diffusivity must
be of this order. In a dynamo model with diffusivity like this, the poloidal
field generated at the mid latitudes is advected toward the poles by the
meridional circulation and simultaneously diffuses towards the tachocline,
where the toroidal field for the next cycle is produced. To model actual solar
cycles with a dynamo model having such high diffusivity, we have to feed the
observational data of the poloidal field at the minimum into the theoretical
model. We develop a method of doing this in a systematic way. Our model
predicts that cycle 24 will be a very weak cycle. Hemispheric asymmetry of
solar activity is also calculated with our model and compared with
observational data.


title: A spectral Erdos-Stone-Bollobas theorem

abstract:
  We give a bound on the spectral radius of a graph implying a quantitative
version of the Erdos-Stone theorem.


title: PEPS as unique ground states of local Hamiltonians

abstract:
  In this paper we consider projected entangled pair states (PEPS) on arbitrary
lattices. We construct local parent Hamiltonians for each PEPS and isolate a
condition under which the state is the unique ground state of the Hamiltonian.
This condition, verified by generic PEPS and examples like the AKLT model, is
an injective relation between the boundary and the bulk of any local region.
While it implies the existence of an energy gap in the 1D case we will show
that in certain cases (e.g., on a 2D hexagonal lattice) the parent Hamiltonian
can be gapless with a critical ground state. To show this we invoke a mapping
between classical and quantum models and prove that in these cases the
injectivity relation between boundary and bulk solely depends on the lattice
geometry.

categories: quant-ph cond-mat.stat-mech math-ph math.MP


title: Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b

abstract:
  We present Spitzer Space Telescope infrared photometry of a primary transit
of the hot Neptune GJ 436b. The observations were obtained using the 8 microns
band of the InfraRed Array Camera (IRAC). The high accuracy of the transit data
and the weak limb-darkening in the 8 microns IRAC band allow us to derive
(assuming M = 0.44 +- 0.04 Msun for the primary) a precise value for the
planetary radius (4.19 +0.21-0.16 Rearth), the stellar radius (0.463
+0.022-0.017 Rsun), the orbital inclination (85.90 +0.19-0.18 degrees) and
transit timing (2454280.78186 +0.00015-0.00008 HJD). Assuming current planet
models, an internal structure similar to that of Neptune with a small H/He
envelope is necessary to account for the measured radius of GJ 436b.


title:
Irreducible Sp-representations and subgroup distortion in the mapping
  class group

abstract:
  We prove that various subgroups of the mapping class group $Mod(\Sigma)$ of a
surface $\Sigma$ are at least exponentially distorted. Examples include the
Torelli group (answering a question of Hamenstadt), the "point-pushing" and
surface braid subgroups, and the Lagrangian subgroup. Our techniques include a
method to compute lower bounds on distortion via representation theory and an
extension of Johnson theory to arbitrary subgroups of $H_1(\Sigma;\mathbb{Z})$.