title: Collisional statistics of the hard-sphere gas

abstract:
  We investigate the probability distribution function of the free flight time
and of the number of collisions in a hard sphere gas at equilibrium. At
variance with naive expectation, the latter quantity does not follow Poissonian
statistics, even in the dilute limit which is the focus of the present
analysis. The corresponding deviations are addressed both numerically and
analytically. In writing an equation for the generating function of the
cumulants of the number of collisions, we came across a perfect mapping between
our problem and a previously introduced model: the probabilistic ballistic
annihilation process [Coppex et al., Phys. Rev. E 69 11303 (2004)]. We exploit
this analogy to construct a Monte-Carlo like algorithm able to investigate the
asymptotically large time behavior of the collisional statistics within a
reasonable computational time. In addition, our predictions are confronted
against the results of Molecular Dynamics simulations and Direct Simulation
Monte Carlo technique. An excellent agreement is reported.


title:
Fidelity susceptibility and long-range correlation in the Kitaev
  honeycomb model

abstract:
  We study exactly both the ground-state fidelity susceptibility and bond-bond
correlation function in the Kitaev honeycomb model. Our results show that the
fidelity susceptibility can be used to identify the topological phase
transition from a gapped A phase with Abelian anyon excitations to a gapless B
phase with non-Abelian anyon excitations. We also find that the bond-bond
correlation function decays exponentially in the gapped phase, but
algebraically in the gapless phase. For the former case, the correlation length
is found to be $1/\xi=2\sinh^{-1}[\sqrt{2J_z -1}/(1-J_z)]$, which diverges
around the critical point $J_z=(1/2)^+$.


title: Lobachevsky geometry of (super)conformal mechanics

abstract:
  We give a simple geometric explanation for the similarity transformation
mapping one-dimensional conformal mechanics to free-particle system. Namely, we
show that this transformation corresponds to the inversion of the Klein model
of Lobachevsky space (non-compact complex projective plane). We also extend
this picture to the N=2k superconformal mechanics described in terms of
Lobachevsky superspace.


title: q1 Eri: a solar-type star with a planet and a dust belt

abstract:
  Only very few solar-type stars exhibiting an infrared excess and harbouring
planets are known to date. Indeed, merely a single case of a star-planet-disk
system has previously been detected at submillimeter (submm) wavelengths.
Consequently, one of our aims is to understand the reasons for these poor
statistics, i.e., whether these results reflected the composition and/or the
physics of the planetary disks or were simply due to observational bias and
selection effects. Finding more examples would be very significant. The
selected target, q1 Eri, is a solar-type star, which was known to possess a
planet, q1 Eri b, and to exhibit excess emission at IRAS wavelengths, but had
remained undetected in the millimeter regime. Therefore, submm flux densities
would be needed to better constrain the physical characteristics of the
planetary disk. Consequently, we performed submm imaging observations of q1
Eri. The detected dust toward q1 Eri at 870 micron exhibits the remarkable fact
that the entire SED, from the IR to mm-wavelengths, is fit by a single
temperature blackbody function (60 K). This would imply that the emitting
regions are confined to a narrow region (ring) at radial distances much larger
than the orbital distance of q1 Eri b, and that the emitting particles are
considerably larger than some hundred micron. However, the 870 micron source is
extended, with a full-width-half-maximum of roughly 600 AU. Therefore, a
physically more compelling model also invokes a belt of cold dust (17 K),
located at 300 AU from the star and about 60 AU wide. The minimum mass of 0.04
Mearth (3 Mmoon) of 1 mm-size icy ring-particles is considerable, given the
stellar age of about 1 Gyr. These big grains form an inner edge at about 25 AU,
which may suggest the presence of an unseen outer planet (q1 Eri c).


title: $Z^+(4430)$ as a $D_1'{D}^* $ ($D_1{D}^* $) molecular state

abstract:
  We reexamine whether $Z^+(4430)$ could be a $D_1'-{D}^*$ or $D_1-{D}^*$
molecular state after considering both the pion and $\sigma$ meson exchange
potentials and introducing the form factor to take into account the structure
effect of the interaction vertex. Our numerical analysis with Matlab package
MATSLISE indicates the contribution from the sigma meson exchange is small for
the $D_1'-{D}^*$ system and significant for the $D_1-{D}^*$ system. The S-wave
$D_1-\bar{D}^*$ molecular state with only $J^{P}=0^-$ and $D_1'-{D}^*$
molecular states with $J^P=0^-,1^-,2^-$ may exist with reasonable parameters.
One should investigate whether the broad width of $D_1'$ disfavors the possible
formation of molecular states in the future. The bottom analog $Z_B$ of
$Z^+(4430)$ has a larger binding energy, which may be searched at Tevatron and
LHC. Experimental measurement of the quantum number of $Z^+(4430)$ may help
uncover its underlying structure.


title:
On the Topology of the Restricted Delaunay Triangulation and Witness
  Complex in Higher Dimensions

abstract:
  It is a well-known fact that, under mild sampling conditions, the restricted
Delaunay triangulation provides good topological approximations of 1- and
2-manifolds. We show that this is not the case for higher-dimensional
manifolds, even under stronger sampling conditions. Specifically, it is not
true that, for any compact closed submanifold M of R^n, and any sufficiently
dense uniform sampling L of M, the Delaunay triangulation of L restricted to M
is homeomorphic to M, or even homotopy equivalent to it. Besides, it is not
true either that, for any sufficiently dense set W of witnesses, the witness
complex of L relative to M contains or is contained in the restricted Delaunay
triangulation of L.


title: Atom-to-molecule conversion efficiency and adiabatic fidelity

abstract:
  The efficiency of converting two-species fermionic atoms into bosonic
molecules is investigated in terms of mean-field Lagrangian density. We find
that the STIRAP technique aided by Feshbach resonance is more effective than
the bare Fechbach resonance for $^6$Li atoms rather than $^{40}$K atoms. We
also make general consideration on the symmetry and its relevant conservation
law, which enable us to introduce a natural definition of adiabatic fidelity
for CPT state. The calculated values of the fidelity then provide an
interpretation on why the conversion efficiencies for $^{40}$K and $^6$Li are
distinctly different.


title: Inverse scattering on conformally compact manifolds

abstract:
  We study inverse scattering for $\Delta_g+V$ on $(X,g)$ a conformally compact
manifold with metric $g,$ with variable sectional curvature $-\alf^2(y)$ at the
boundary and $V\in C^\infty(X)$ not vanishing at the boundary. We prove that
the scattering matrix at a fixed energies $(\lambda_1,$ $\lambda_2)$ in a
suitable subset of $\mc$, determines $\alf,$ and the Taylor series of both the
potential and the metric at the boundary.


title:
Charges and Mass Spectrum in the Pisano-Pleitez-Frampton 3-3-1 Gauge
  Model

abstract:
  The Pisano-Pleitez-Frampton 3-3-1 model is revisited here within the
framework of the general method for solving gauge models with high symmetries.
This exact algebraical approach - proposed several years ago by one of us - was
designed to include a minimal Higgs mechanism that spontaneously breaks the
gauge symmetry up to the universal $U(1)_{em}$ electromagnetic one and,
consequently, to supply the mass spectrum and the couplings of the currents for
all the particles in the model. We prove in this paper that this powerful tool,
when is applied to the PPF 3-3-1 model, naturally recovers the whole Standard
Model phenomenology and, in addition, predicts - since a proper parametrization
is employed - viable results such as: (i) the exact expressions for the boson
and fermion masses, (ii) the couplings of the charged and neutral currents and
(iii) a plausible neutrino mass pattern. A generalized Weinberg transformation
is implemented, while the mixing between the neutral bosons $Z$ and
$Z^{\prime}$ is performed as a necessary step by the method itself. Some
phenomenological consequences are also sketched, including the strange
possibility that simultaneously $m(Z)=m(Z^{\prime})$ and $m(W)=m(V)$ hold.


title: A volume-weighted measure for eternal inflation

abstract:
  I propose a new volume-weighted probability measure for cosmological
"multiverse" scenarios involving eternal inflation. The "reheating-volume (RV)
cutoff" calculates the distribution of observable quantities on a portion of
the reheating hypersurface that is conditioned to be finite. The RV measure is
gauge-invariant, does not suffer from the "youngness paradox," and is
independent of initial conditions at the beginning of inflation. In slow-roll
inflationary models with a scalar inflaton, the RV-regulated probability
distributions can be obtained by solving nonlinear diffusion equations. I
discuss possible applications of the new measure to "landscape" scenarios with
bubble nucleation. As an illustration, I compute the predictions of the RV
measure in a simple toy landscape.


title: Kinematics of AGN and Quasar Jets

abstract:
  The major multi-epoch VLBA programs are described and discussed in terms of
relativistic beaming models. Broadly speaking the observed kinematics are
consistent with models having a parent population which is only mildly
relativistic but with Lorentz factors extending up to about 30. While the
collimation and acceleration appears to mainly occur close to the central
engine, there is evidence of accelerations up to 1 kpc downstream. Generally
the motion appears to be linear, but in some sources the motion follows a
curved trajectory. In other sources, successive features appear to be ejected
in different directions possibly the result of a precessing nozzle.
  The launch of GLAST in 2008 will offer new opportunities to study the
relation between radio and gamma-ray activity, and possibly to locate the
source of the gamma-ray emission. VSOP-2 will give enhanced resolution and will
facilitate the study of the two-dimensional structure of relativistic jets,
while RadioAstron will provide unprecedented resolution to study the fine scale
structure of the jet base.


title:
Rational structure on algebraic tangles and closed incompressible
  surfaces in the complements of algebraically alternating knots and links

abstract:
  Let $F$ be an incompressible, meridionally incompressible and not
boundary-parallel surface with boundary in the complement of an algebraic
tangle $(B,T)$. Then $F$ separates the strings of $T$ in $B$ and the boundary
slope of $F$ is uniquely determined by $(B,T)$ and hence we can define the
slope of the algebraic tangle. In addition to the Conway's tangle sum, we
define a natural product of two tangles. The slopes and binary operation on
algebraic tangles lead an algebraic structure which is isomorphic to the
rational numbers.
  We introduce a new knot and link class, algebraically alternating knots and
links, roughly speaking which are constructed from alternating knots and links
by replacing some crossings with algebraic tangles. We give a necessary and
sufficient condition for a closed surface to be incompressible and meridionally
incompressible in the complement of an algebraically alternating knot or link
$K$, in particular we show that if $K$ is a knot, then the complement of $K$
does not contain such a surface.


title: Explicit exact expression for the Thomas precession

abstract:
  This work gives an explicit exact expression for the Thomas precession
arising in the framework of Special Theory of Relativity as the spatial
rotation resulting from two subsequence Lorentz boosts. The final result for
the orthogonal matrix of Thomas precession is given by Eqs. (21)--(25). A
trivial calculation leads to the compact formula (26) for the angle of rotation
due to Thomas precession.
  In the framework of Gaia the special-relativistic Thomas precession is an
important step in the derivation of an aberrational formula with the
Mansouri-Sexl parameters. The latter formula will be used to test the Local
Lorentz Invariance with Gaia data as will be explained elsewhere.


title: Euler-Hurwitz series and non-linear Euler sums

abstract:
  In this paper we derive two expressions for the Hurwitz zeta function
involving the complete Bell polynomials in the restricted case where q is a
positive integer greater than 1. The arguments of the complete Bell polynomials
comprise the generalised harmonic number functions. These in turn give rise to
Euler-Hurwitz series which may then be used to determine identities for
combinations of both linear and non-linear Euler sums.


title:
More on Algebraic Structure of the Complete Partition Function for the $
  Z_n $ - Potts Model, Part 1

abstract:
  In this first part of a larger review undertaking the results of the first
author and a part of the second author doctor dissertation are presented. Next
we plan to give a survey of a nowadays situation in the area of investigation.
Here we report on what follows.
  Calculation of the partition function for any vector potts model is at first
reduced to the calculation of traces of products of the generalized clifford
algebra generators. The formula for such traces is derived. This enables one,
in principle, to use an explicit calculation algorithm for partition functions
also in other models for which the transfer matrix is an element from
generalized clifford algebra. The method - simple for $Z_2$ case - becomes
complicated for $Z_n$, $n>2$, however everything is controlled, in principle,
due to knowledge of the corresponding algebra properties and those of
generalized cosh function. The discussion of the content of the in statu
nascendi second part is to be found at the end of this presentation. This
constitutes the last section.


title: An evaluation of the osmotic method of controlling suction

abstract:
  Experimental techniques of testing the mechanical properties of unsaturated
soils are complex and difficult to conduct. As a consequence, complete sets of
parameters that characterise the behaviour of unsaturated soils remain scarce
and necessary. In this context, it has been found useful to gather the
information obtained after some years of practice of the osmotic technique of
controlling suction. As compared to the more documented axis-translation
technique, the osmotic technique has its own advantages and drawbacks that are
discussed in this paper, together with some potential future developments. The
osmotic method has been developed by soil scientists in the 1960s and adapted
to geotechnical testing in the early 1970s. This paper presents the osmotic
technique and comments on its advantages (including suction condition close to
reality and higher suctions easily attained) and drawbacks (including some
concern with the membrane resistance and some membrane effects in the
suction/concentration calibration). Various applications to geotechnical
testing are presented such as the determination of the water retention curve,
oedometer and triaxial testing procedures and the determination of the
permeability of unsaturated soils. Recent developments, that include the
extension of the method up to high suctions (10 MPa) are also described,
together with some recent and novel applications such as data from high
controlled suction oedometer compression test and the determination of the
oil/water retention properties of oil reservoir chalks.


title:
Pion-less Effective Field Theory on Low-Energy Deuteron
  Electro-Disintegration

abstract:
  In view of its relation to Big-Bang Nucleo-Synthesis and a reported
discrepancy between nuclear models and data taken at S-DALINAC, electro-induced
deuteron break-up 2H(e,e' p)n is studied at momentum transfer q<100MeV and
close to threshold in the low-energy nuclear Effective Field Theory without
dynamical pions. The result at N2LO for electric dipole currents and at NLO for
magnetic ones converges order-by-order better than quantitatively predicted and
contains no free parameter. It is at this order determined by simple,
well-known observables. Decomposing the doubly differential cross-section into
the longitudinal-plus-transverse (L+T), transverse-transverse (TT) and
longitudinal-transverse interference (LT) terms, we find excellent agreement
with a potential-model calculation by Arenh"ovel et al using the Bonn
potential. Theory and data also agree well on \sigma_{L+T}. There is however no
space on the theory-side for the discrepancy of up to 30%, 3-\sigma between
theory and experiment in \sigma_{LT}. From universality, we conclude that no
theoretical approach with the correct deuteron asymptotic wave-function can
explain the data. Un-determined short-distance contributions that could affect
\sigma_{LT} enter only at high orders, i.e. at the few-percent level. We notice
some issues with the kinematics and normalisation of the data reported.


title: Subsidence and capillary effects in chalks

abstract:
  Based on the concepts of the mechanics of unsaturated soils where capillary
phenomena arise between the wetting fluid (water) and the non-wetting one
(air), the subsidence of chalks containing oil (non-wetting fluid) during water
injection (wetting fluid) is analysed. It is shown that the collapse phenomenon
of unsaturated soils under wetting provides a physical explanation and a
satisfactory prediction of the order of magnitude of the subsidence of the
chalk. The use of a well established constitutive model for unsaturated soils
allows a description of the hydro-mechanical history of the chalk, from its
deposition to the oil exploitation.


title:
Zeldovich Lambda and Weinberg Relation: An Explanation for the
  Cosmological Coincidences

abstract:
  In 1937 Dirac proposed the large number hypothesis (LNH). The idea was to
explain that these numbers were large because the Universe is old. A time
variation of certain constants was assumed. So far, no experimental evidence
has significantly supported this time variation. Here we present a simplified
cosmological model. We propose a new cosmological system of units, including a
cosmological Planck constant that absorbs the well known large number 10120.
With this new Planck constant no large numbers appear at the cosmological
level. They appear at lower levels, e.g. at the quantum world. We note here
that Zeldovich formula, for the cosmological constant, is equivalent to the
Weinberg relation. The immediate conclusion is that the speed of light c must
be proportional to the Hubble parameter H, and therefore decrease with time. We
find that the gravitational radius of the Universe and its size are one and the
same constant (Mach principle). The usual cosmological omega parameters for
mass, lambda and curvature turn out to be all constants of order one. The
anthropic principle is not necessary in this theory. It is shown that a factor
of 1061converts in this theory a Planck fluctuation (a quantum black hole) into
a cosmological quantum black hole: the Universe today. General relativity and
quantum mechanics give the same local solution of an expanding Universe with
the law const. t. This constant is just the speed of light today. Then the
Hubble parameter is exactly H = 1/t.


title: Note sur les corps 2-rationnels

abstract:
  We compute the Galois group of the maximal 2-ramified pro-2-extension of a
2-rational number field


title:
Reconstructing the universe history, from inflation to acceleration,
  with phantom and canonical scalar fields

abstract:
  We consider the reconstruction technique in theories with a single or
multiple (phantom and/or canonical) scalar fields. With the help of several
examples, it is demonstrated explicitly that the universe expansion history,
unifying early-time inflation and late-time acceleration, can be realized in
scalar-tensor gravity. This is generalized to the theory of a scalar field
coupled non-minimally to the curvature and to a Brans-Dicke-like theory.
Different examples of unification of inflation with cosmic acceleration, in
which de Sitter, phantom, and quintessence type fields play the fundamental
role--in different combinations--are worked out. Specifically, the frame
dependence and stability properties of de Sitter space scalar field theory are
studied. Finally, for two-scalar theories, the late-time acceleration and
early-time inflation epochs are successfully reconstructed, in realistic
situations in which the more and more stringent observational bounds are
satisfied, using the freedom of choice of the scalar field potential, and of
the kinetic factor.


title: Crystal-to-stripe reordering of sodium ions in NaxCoO2 (x>=0.75)

abstract:
  The sodium reordering in NaxCoO2 in the vicinity of room temperature is
rationalized at high x in terms of phase transitions between square and striped
phases. A striking hexagon-of-hexagons diffraction pattern observed for x=0.78
can be reproduced using coexisting square and striped phases that are related
by simple shear deformations. All compositions exhibit a partial melting
transition to a disordered stripe phase just below room temperature, which
alters the topology of the electrical conduction pathways.


title:
A proof by calibration of an isoperimetric inequality in the Heisenberg
  group H^n

abstract:
  Let $D$ be a closed disk centered at the origin in the horizontal hyperplane
$\{t=0\}$ of the sub-Riemannian Heisenberg group $\hh^n$, and $C$ the vertical
cylinder over $D$. We prove that any finite perimeter set $E$ such that
$D\subset E\subset C$ has perimeter larger than or equal to the one of the
rotationally symmetric sphere with constant mean curvature of the same volume,
and that equality holds only for the spheres using a recent result by Monti and
Vittone [12].


title:
Examples of area-minimizing surfaces in the subriemannian Heisenberg
  group H^1 with low regularity

abstract:
  We give new examples of entire area-minimizing t-graphs in the subriemannian
Heisenberg group H^1. Most of the examples are locally lipschitz in Euclidean
sense. Some regular examples have prescribed singular set consisting of either
a horizontal line or a finite number of horizontal halflines extending from a
given point. Amongst them, a large family of area-minimizing cones is obtained.


title: Gauge-String Dualities and Some Applications

abstract:
  The first part of these lectures contains an introductory review of the
AdS/CFT duality and of its tests. Applications to thermal gauge theory are also
discussed briefly. The second part is devoted to a review of gauge-string
dualities based on various warped conifold backgrounds, and to their
cosmological applications.


title: Octonionic twists for supermembrane matrix models

abstract:
  A certain G_2 times U(1) invariant Hamiltonian arising from the standard
membrane matrix model via conjugating any of the supercharges by a cubic,
octonionic, exponential is proven to have a spectrum covering the whole
positive half-axis. The model could be useful in determining a normalizable
zero-energy state in the original SO(9) invariant SU(N) matrix model.


title: Simplices and spectra of graphs

abstract:
  In this note we show the n-2-dimensional volumes of codimension 2 faces of an
n-dimensional simplex are algebraically independent functions of the lengths of
edges. In order to prove this we compute the complete spectrum of a
combinatorially interesting graph.


title:
Global regularity for a modified critical dissipative quasi-geostrophic
  equation

abstract:
  In this paper, we consider the modified quasi-geostrophic equation
\begin{gather*} \del_t \theta + (u \cdot \grad) \theta + \kappa \Lambda^\alpha
\theta = 0 u = \Lambda^{\alpha - 1} R^{\perp}\theta. \end{gather*} with $\kappa
> 0$, $\alpha \in (0,1]$ and $\theta_0 \in \lp{2}(\R^2)$. We remark that the
extra $\Lambda^{\alpha - 1}$ is introduced in order to make the scaling
invariance of this system similar to the scaling invariance of the critical
quasi-geostrophic equations. In this paper, we use Besov space techniques to
prove global existence and regularity of strong solutions to this system.


title: The repulsive force in continous space models of pedestrian movement

abstract:
  Pedestrian movements can be modeled at different degrees of detail. While
flux models (Predeshensky/Milinski 1971) and cellular automata models
(Schreckenberg 2002) give answers to some important questions and are fast and
easy to use, continuous space modeling has the potential of full flexibility in
geometry and realistic description of individual movements in arbitrary fine
resolution. While the acceleration forces in these models are known with good
reliability, there is no agreement on the repulsive forces, not even on the
functional form of these forces (Lakoba 2005, Molnar 1996, Parisi 2005, Yu
2005). We give some basic consideration to define the minimal complexity of the
functional form of the repulsive forces together with some estimates of the
values of parameters. From these considerations it becomes obvious that the
repulsive forces have to depend not only on the relative position of persons,
but also on the speeds and speed differences. The parameters of these forces
will be situation dependant. They can in principle be derived from video
observations of people moving, although the large scatter of data and the
complexity involved makes for large uncertainties.


title: Hopf algebras of primitive Lie pseudogroups and Hopf cyclic cohomology

abstract:
  We associate to each infinite primitive Lie pseudogroup a Hopf algebra of
`transverse symmetries', by refining a procedure due to Connes and the first
author in the case of the general pseudogroup. The affiliated Hopf algebra can
be viewed as a `quantum group' counterpart of the infinite-dimensional
primitive Lie algebra of the pseudogroup. It is first constructed via its
action on the \'etale groupoid associated to the pseudogroup, and then realized
as a bicrossed product of a universal enveloping algebra by a Hopf algebra of
regular functions on a formal group. The bicrossed product structure allows to
express its Hopf cyclic cohomology in terms of a bicocyclic bicomplex analogous
to the Chevalley-Eilenberg complex. As an application, we compute the relative
Hopf cyclic cohomology modulo the linear isotropy for the Hopf algebra of the
general pseudogroup, and find explicit cocycle representatives for the
universal Chern classes in Hopf cyclic cohomology. As another application, we
determine all Hopf cyclic cohomology groups for the Hopf algebra associated to
the pseudogroup of local diffeomorphisms of the line.


title: Treewidth computation and extremal combinatorics

abstract:
  For a given graph G and integers b,f >= 0, let S be a subset of vertices of G
of size b+1 such that the subgraph of G induced by S is connected and S can be
separated from other vertices of G by removing f vertices. We prove that every
graph on n vertices contains at most n\binom{b+f}{b} such vertex subsets. This
result from extremal combinatorics appears to be very useful in the design of
several enumeration and exact algorithms. In particular, we use it to provide
algorithms that for a given n-vertex graph G - compute the treewidth of G in
time O(1.7549^n) by making use of exponential space and in time O(2.6151^n) and
polynomial space; - decide in time O(({\frac{2n+k+1}{3})^{k+1}\cdot kn^6}) if
the treewidth of G is at most k; - list all minimal separators of G in time
O(1.6181^n) and all potential maximal cliques of G in time O(1.7549^n). This
significantly improves previous algorithms for these problems.


title: A complex surface of general type with p_g=0, K^2=3 and H_1=Z/2Z

abstract:
  This paper is an addendum to [4], in which the authors constructed a simply
connected minimal complex surface of general type with p_g=0 and K^2=3. In this
paper we construct a new non-simply connected minimal surface of general type
with p_g=0, K^2=3 and H_1=Z/2Z using a rational blow-down surgery and
Q-Gorenstein smoothing theory.


title:
A Game Theoretic Framework for Decentralized Power Allocation in IDMA
  Systems

abstract:
  In this contribution we present a decentralized power allocation algorithm
for the uplink interleave division multiple access (IDMA) channel. Within the
proposed optimal strategy for power allocation, each user aims at selfishly
maximizing its own utility function. An iterative chip by chip (CBC) decoder at
the receiver and a rational selfish behavior of all the users according to a
classical game-theoretical framework are the underlying assumptions of this
work. This approach leads to a power allocation based on a channel inversion
policy where the optimal power level is set locally at each terminal based on
the knowledge of its own channel realization, the noise level at the receiver
and the number of active users in the network.


title: Cluster Dynamical Mean Field Theory of the Mott Transition

abstract:
  We address the nature of the Mott transition in the Hubbard model at
half-filling using cluster Dynamical Mean Field Theory (DMFT). We compare
cluster DMFT results with those of single site DMFT. We show that inclusion of
the short range correlations on top of the on-site correlations, already
treated exactly in single site DMFT, do not change the nature of the transition
between the paramagnetic metal and the paramagnetic Mott insulator, which
remains first order. However, the short range correlations reduce substantially
the critical $U$ and modify the shape of transition lines. Moreover, they lead
to very different physical properties of the metallic and insulating phases
near the transition, in particular in the region of the phase diagram where the
two solutions coexist. Approaching the transition from the metallic side, we
find an anomalous metallic state with very low coherence scale at temperatures
as low as $T=0.01t$. The insulating state is characterized by the relatively
narrow Mott gap with pronounced peaks at the gap edge.


title:
Entropy driven stabilization of energetically unstable crystal
  structures explained from first principles theory

abstract:
  Conventional methods to calculate the thermodynamics of crystals evaluate the
harmonic phonon spectra and therefore do not work in frequent and important
situations where the crystal structure is unstable in the harmonic
approximation, such as the body-centered cubic (bcc) crystal structure when it
appears as a high-temperature phase of many metals. A method for calculating
temperature dependent phonon spectra self consistently from first principles
has been developed to address this issue. The method combines concepts from
Born's inter-atomic self-consistent phonon approach with first principles
calculations of accurate inter-atomic forces in a super-cell. The method has
been tested on the high temperature bcc phase of Ti, Zr and Hf, as
representative examples, and is found to reproduce the observed high
temperature phonon frequencies with good accuracy.


title: Classical Electrodynamics without Fields and the Aharonov-Bohm effect

abstract:
  The Darwin-Breit Hamiltonian is applied to the Aharonov-Bohm experiment. In
agreement with the standard Maxwell-Lorentz theory, the force acting on
electrons from infinite solenoids or ferromagnetic rods vanishes. However, the
interaction energies and phase factors of the electron wave packets are
non-zero. This allows us to explain the Aharonov-Bohm effect without
involvement of electromagnetic potentials, fields, and topological properties
of space.


title: Covariants and the no-name lemma

abstract:
  A close connection between the no-name lemma (concerning algebraic groups
acting on vector bundles) and the existence of sufficiently many independent
rational covariants is pointed out. In particular, this leads to a new natural
proof of the no-name lemma. For linearly reductive groups, the approach has a
refined variant based on integral covariants. This fits into the usual context
of invariant theory, and yields a version of the no-name lemma that has a
constructive nature.


title: Quivers with potentials associated to triangulated surfaces

abstract:
  We attempt to relate two recent developments: cluster algebras associated to
triangulations of surfaces by Fomin-Shapiro-Thurston, and quivers with
potentials and their mutations introduced by Derksen-Weyman-Zelevinsky. To each
ideal triangulation of a bordered surface with marked points we associate a
quiver with potential, in such a way that whenever two ideal triangulations are
related by a flip of an arc, the respective quivers with potentials are related
by a mutation with respect to the flipped arc. We prove that if the surface has
non-empty boundary, then the quivers with potentials associated to its
triangulations are rigid and hence non-degenerate.


title:
Cyanopolyynes and sulphur bearing species in hot cores: Chemical and
  line excitation models

abstract:
  We present results from a time dependent gas phase chemical model of a hot
core based on the physical conditions of G305.2+0.2. While the cyanopolyyne
HC_3N has been observed in hot cores, the longer chained species, HC_5N, HC_7N,
and HC_9N have not been considered typical hot core species. We present results
which show that these species can be formed under hot core conditions. We
discuss the important chemical reactions in this process and, in particular,
show that their abundances are linked to the parent species acetylene which is
evaporated from icy grain mantles. The cyanopolyynes show promise as `chemical
clocks' which may aid future observations in determining the age of hot core
sources. The abundance of the larger cyanopolyynes increase and decrease over
relatively short time scales, ~10^2.5 years. We also discuss several sulphur
bearing species. We present results from a non-LTE statistical equilibrium
excitation model as a series of density, temperature and column density
dependent contour plots which show both the line intensities and several line
ratios. These aid in the interpretation of spectral line data, even when there
is limited line information available.


title: Application of Quantum Darwinism to Diffusion during Cosmic Inflation

abstract:
  A baby-universe model of cosmic inflation is analyzed using quantum
Darwinism. In this model cosmic inflation can be approximated as Brownian
motion of a quantum field, and quantum Darwinism implies that decoherence is
the result of quantum Brownian motion of the wave function. The quantum
Darwinism approach to decoherence in the baby-universe cosmic-inflation model
yields the decoherence times of the baby-universes. The result is the equation
relating the baby-universe's decoherence time with the Hubble parameter. A
brief discussion of the relation between Darwinism and determinism is provided
in the Appendix.


title: Arithmetic Groups Have Rational Representation Growth

abstract:
  Let G be an arithmetic lattice in a semisimple algebraic group over a number
field. We show that if G has the congruence subgroup property, then the number
of n-dimensional irreducible representations of G grows like n^a, where a is a
rational number.


title: Cohen-Macaulay admissible clutters

abstract:
  There is a one-to-one correspondence between square-free monomial ideals and
clutters, which are also known as simple hypergraphs. It was conjectured that
unmixed admissible clutters are Cohen-Macaulay. We prove the conjecture for
uniform admissible clutters of heights 2 and 3. For admissible clutters of
greater heights, we give a family of examples to show that the conjecture may
fail. When the height is 4, we give an additional condition under which unmixed
admissible clutters are Cohen-Macaulay.


title: Minimality of the well-rounded retract

abstract:
  We prove that the well-rounded retract of SO_n\SL_n(R) is a minimal
SL_n(Z)-invariant spine.


title: Two possible approaches to form sub-millisecond pulsars

abstract:
  Pulsars have been recognized as normal neutron stars or quark stars.
Sub-millisecond pulsars, if detected, would play an essential and important
role in distinguishing quark stars from neutron stars. A key question is how
sub-millisecond pulsars could form. Both sub-Keplerian (for neutron and quark
stars) and super-Keplerian cases (only for quark stars, which are bound
additionally by strong interaction) have been discussed in this paper in order
to investigate possible ways of forming sub-millisecond pulsars. In the
sub-Keplerian case, the equilibrium periods of both neutron and quark stars
could be as low as ~0.4 ms when they are spun up through accretion in binary
systems. In the super-Keplerian case, pulsars could very likely have an initial
period of ~0.1 ms if quark stars with different mass could be formed from
accretion-induced collapse (AIC) of white dwarfs. The timescale for a
sub-millisecond pulsar to keep its period <1 ms is restricted due to
gravitational wave radiation. We found that the timescales of neutron stars
within sub-millisecond periods are approximately ~10 yr, but the timescales
estimated (>10 Myr) for low-mass quark stars could be long enough for us to
detect.


title:
The littlest Higgs model with T-parity and single top production at $ep$
  collision

abstract:
  Based on calculating the contributions of the littlest Higgs model with
T-parity (called $LHT$ model) to the anomalous top coupling $tq\gamma$ ($q=u$
or $c$), we consider single top production via the t-channel partonic process
$eq\to et$ at $ep$ collision. Our numerical results show that the production
cross section in the $LHT$ model can be significantly enhanced relative to that
in the standard model.


title: Primitive Central Idempotents of the Group Algebra

abstract:
  An approach to representations of finite groups is presented without recourse
to character theory. Considering the group algebra C[G] as an algebra of linear
maps on C[G] (by left multiplication), we derive the primitive central
idempotents as a simultaneous eigenbasis of the centre, Z(C[G]). We apply this
framework to obtain the irreducible representations of a class of finite
meta-abelian groups. In particular, we give a general construction of the
isomorphism between simple blocks of C[G] and the corresponding matrix algebra
where G can be any finite group.


title:
Analysis of Incident-Photon-Energy and Polarization Dependent Resonant
  Inelastic X-Ray Scattering from La$_{2}$CuO$_{4}$

abstract:
  We present a detailed analysis of the incident-photon-energy and polarization
dependences of the resonant inelastic x-ray scattering (RIXS) spectra at the Cu
$K$ edge in La$_{2}$CuO$_{4}$. Our analysis is based on the formula developed
by Nomura and Igarashi, which describes the spectra by a product of an
incident-photon-dependent factor and a density-density correlation function for
3d states. We calculate the former factor using the $4p$ density of states from
an ab initio band structure calculation and the latter using a multiorbital
tight-binding model within the Hartree-Fock approximation and the random phase
approximation. We obtain spectra with rich structures in the energy-loss range
2-5 eV, which vary with varying momentum and incident-photon energy, in
semi-quantitative agreement with recent experiments. We clarify the origin of
such changes as a combined effect of the incident-photon-dependent factor and
the density-density correlation function.


title:
Anomalies, effective action and Hawking temperatures of a Schwarzschild
  black hole in the isotropic coordinates

abstract:
  Motivated by the universality of Hawking radiation and that of the anomaly
cancellation technique as well as that of the effective action method, we
investigate the Hawking radiation of a Schwarzschild black hole in the
isotropic coordinates via the cancellation of gravitational anomaly. After
performing a dimensional reduction from the four-dimensional isotropic
Schwarzschild metric, we show that this reduction procedure will, in general,
result in two classes of two-dimensional effective metrics: the conformal
equivalent and the inequivalent ones. For the physically equivalent class, the
two-dimensional effective metric displays such a distinct feature that the
determinant is not equal to the unity ($\sqrt{-g} \neq 1$), but also vanishes
at the horizon, the latter of which possibly invalidates the anomaly analysis
there. ...
  This is an updated version to replace our e-print arXiv:0709.0044 [hep-th].
Abstract is too long to exceed the limit of 24 lines by arXiv.


title:
Generating function for GL_n-invariant differential operators in the
  skew Capelli identity

abstract:
  Let Alt_n be the vector space of all alternating n-by-n complex matrices, on
which the complex general linear group GL_n acts by $x \mapsto g x g^t$. The
aim of this paper is to show that Pfaffian of a certain matrix whose entries
are multiplication operators or derivations acting on polynomials on Alt_n
provides a generating function for the GL_n-invariant differential operators
that play a role in the skew Capelli identity, with coefficients the Hermite
polynomials.


title: Quantum Field Theory and Differential Geometry

abstract:
  We introduce the historical development and physical idea behind topological
Yang-Mills theory and explain how a physical framework describing subatomic
physics can be used as a tool to study differential geometry. Further, we
emphasize that this phenomenon demonstrates that the interrelation between
physics and mathematics have come into a new stage.

categories: physics.pop-ph hep-th math-ph math.DG math.MP


title: Two ultracold atoms in a completely anisotropic trap

abstract:
  As a limiting case of ultracold atoms trapped in deep optical lattices, we
consider two interacting atoms trapped in a general anisotropic harmonic
oscillator potential, and obtain exact solutions of the Schrodinger equation
for this system. The energy spectra for different geometries of the trapping
potential are compared.


title:
Teleportation of composite systems for communication and information
  processing

abstract:
  We describe two protocols for efficient data transmission using a single
passive bus. Different types of interactions are obtained enabling
deterministic transfer and teleportation of composite quantum systems for
arbitrary subsystem dimension and for arbitrary numbers of subsystems. The
subsystems may become entangled in the transmission in which case the protocols
can serve generalized teleportation based information processing as well as
storage and transmission functions. We explore the cases of two qubits and two
qutrits in detail, obtaining a maximally entangling mapping of the composite
systems and discuss the use of a continuous variable bus.


title:
Boundary criticality and multifractality at the 2D spin quantum Hall
  transition

abstract:
  Multifractal scaling of critical wave functions at a disorder-driven
(Anderson) localization transition is modified near boundaries of a sample.
Here this effect is studied for the example of the spin quantum Hall plateau
transition using the supersymmetry technique for disorder averaging. Upon
mapping of the spin quantum Hall transition to the classical percolation
problem with reflecting boundaries, a number of multifractal exponents
governing wave function scaling near a boundary are obtained exactly. Moreover,
additional exact boundary scaling exponents of the localization problem are
extracted, and the problem is analyzed in other geometries.


title: Wild Harmonic Bundles and Wild Pure Twistor D-modules

abstract:
  We study (i) asymptotic behaviour of wild harmonic bundles, (ii) the relation
between semisimple meromorphic flat connections and wild harmonic bundles,
(iii) the relation between wild harmonic bundles and polarized wild pure
twistor $D$-modules. As an application, we show the hard Lefschetz theorem for
algebraic semisimple holonomic $D$-modules, conjectured by M. Kashiwara.


title: Line junction in a quantum Hall system with two filling fractions

abstract:
  We present a microscopic model for a line junction formed by counter or
co-propagating single mode quantum Hall edges corresponding to different
filling factors. The ends of the line junction can be described by two possible
current splitting matrices which are dictated by the conditions of both lack of
dissipation and the existence of a linear relation between the bosonic fields.
Tunneling between the two edges of the line junction then leads to a
microscopic understanding of a phenomenological description of line junctions
introduced some time ago. The effect of density-density interactions between
the two edges is considered, and renormalization group ideas are used to study
how the tunneling parameter changes with the length scale. This leads to a
power law variation of the conductance of the line junction with the
temperature. Depending on the strength of the interactions the line junction
can exhibit two quite different behaviors. Our results can be tested in bent
quantum Hall systems fabricated recently.


title:
Good formal structure for meromorphic flat connections on smooth
  projective surfaces

abstract:
  We prove the algebraic version of a conjecture of C. Sabbah on the existence
of the good formal structure for meromorphic flat connections on surfaces after
some blow up.


title: On Hawking/Unruh Process: Where does the Radiation Come from?

abstract:
  The energy source of the radiation in Unruh/Hawking process is investigated
with emphasis on the particle number definition based on conservation laws. It
has been shown that the particle radiation is not the result of pair creation
by the gravitational force, but the result of difference in the conservation
laws to define the particle number. The origin of the radiated energy in the
distant future corresponds to the zero point oscillations with infinitely large
wave numbers. This result implies the need of reconsideration on the scenario
of black hole evaporation.


title:
A report on "Regulators of canonical extension are torsion; the smooth
  divisor case"

abstract:
  In this note, we report on a work jointly done with C. Simpson on a
generalization of Reznikov's theorem which says that the Chern-Simons classes
and in particular the Deligne Chern classes (in degrees $> 1$) are torsion, of
a flat vector bundle on a smooth complex projective variety. We consider the
case of a smooth quasi--projective variety with an irreducible smooth divisor
at infinity. We define the Chern-Simons classes of the Deligne's
\textit{canonical extension} of a flat vector bundle with unipotent monodromy
at infinity, which lift the Deligne Chern classes and prove that these classes
are torsion. The details of the proof can be found in arxiv:0707.0372
[math.AG].


title: Dynamical mean-field approximation for unitary Fermi gas

abstract:
  Dynamical mean-field approximation with explicit pairing is utilized to study
the properties of a two-component Fermi gas at unitarity. The problem is
approximated by the lattice Hubbard Hamiltonian, and the continuum limit is
realized by diluting the lattice. We have found that at zero temperature the
predictions of this theory for the energy and the pairing gap agree remarkably
well with the results of full numerical Monte-Carlo simulations. Investigating
the evolution of the system with temperature we identify the existence of a
second order phase transition associated with a jump in the heat capacity and
the collapse of the pairing gap.


title: Quantum Correlations over Long-distances Using Noisy Quantum Repeaters

abstract:
  Quantum correlations as the resource for quantum communication can be
distributed over long distances by quantum repeaters. In this Letter, we
introduce the notion of a noisy quantum repeater, and examine its role in
quantum communication. Quantum correlations shared through noisy quantum
repeaters are then characterized and their secrecy properties are studied.
Remarkably, noisy quantum repeaters naturally introduce private states in the
key distillation scenario, and consequently key distillation protocols are
demonstrated to be more tolerant.


title:
Defect generation in a spin-1/2 transverse XY chain under repeated
  quenching of the transverse field

abstract:
  We study the quenching dynamics of a one-dimensional spin-1/2 $XY$ model in a
transverse field when the transverse field $h(=t/\tau)$ is quenched repeatedly
between $-\infty$ and $+\infty$. A single passage from $h \to - \infty$ to $h
\to +\infty$ or the other way around is referred to as a half-period of
quenching. For an even number of half-periods, the transverse field is brought
back to the initial value of $-\infty$; in the case of an odd number of
half-periods, the dynamics is stopped at $h \to +\infty$. The density of
defects produced due to the non-adiabatic transitions is calculated by mapping
the many-particle system to an equivalent Landau-Zener problem and is generally
found to vary as $1/\sqrt{\tau}$ for large $\tau$; however, the magnitude is
found to depend on the number of half-periods of quenching. For two successive
half-periods, the defect density is found to decrease in comparison to a single
half-period, suggesting the existence of a corrective mechanism in the reverse
path. A similar behavior of the density of defects and the local entropy is
observed for repeated quenching. The defect density decays as $1/{\sqrt\tau}$
for large $\tau$ for any number of half-periods, and shows a increase in kink
density for small $\tau$ for an even number; the entropy shows qualitatively
the same behavior for any number of half-periods. The probability of
non-adiabatic transitions and the local entropy saturate to 1/2 and $\ln 2$,
respectively, for a large number of repeated quenching.


title:
Microfluidic velocimetry reveals spatial cooperativity in soft glassy
  flows

abstract:
  Amorphous glassy materials of diverse nature -- concentrated emulsions,
granular materials, pastes, molecular glasses -- display complex flow
properties, intermediate between solid and liquid, which are at the root of
their use in many applications. A classical feature, well documented yet not
really understood, is the very non-linear nature of the flow rule relating
stresses and strain rates. Using a microfluidic velocimetry technique, we
characterize the flow of thin layers of concentrated emulsions, confined in
gaps of different thicknesses by surfaces of different roughness. Beyond the
classical non-linearities of the rheological behaviour, we evidence finite size
effects in the flow behaviour and the absence of an intrinsic local flow rule.
In contrast, a rather simple non-local flow rule is shown to account for all
the velocity profiles. This non-locality of the dynamics is quantified by a
length, characteristic of the cooperativity of the flow at these scales, that
is unobservable in the liquid state (lower concentrations) and that increases
with concentration in the jammed state. Beyond its practical importance for
applications involving thin layers, e.g. coatings, our assessment of
non-locality and cooperativity echoes observations on other glassy, jammed and
granular systems, suggesting a possible fundamental universality.


title:
Probabilistic signatures of spatiotemporal intermittency in the coupled
  sine circle map lattice

abstract:
  The phase diagram of the coupled sine circle map lattice exhibits a variety
of interesting phenomena including spreading regions with spatiotemporal
intermittency, non-spreading regions with spatial intermittency, and coherent
structures termed solitons. A cellular automaton mapping of the coupled map
lattice maps the spreading to non-spreading transition to a transition from a
probabilistic to a deterministic cellular automaton. The solitonic sector of
the map shows spatiotemporal intermittency with soliton creation, propagation
and annihilation. A probabilistic cellular automaton mapping is set up for this
sector which can identify each one of these phenomena.


title: The Tayler instability and the Hall effect in protoneutron stars

abstract:
  Collapse calculations indicate that the hot newly born protoneutron stars
(PNS) rotate differentially so that strong toroidal magnetic field components
should exist in the outer crust where also the Hall effect appears to be
important when the Hall parameter \hat\beta=\omega_B \tau is of order unity.
The amplitudes of the induced toroidal magnetic fields are limited from above
by the Tayler instability. An important characteristic of the Hall effect is
its distinct dependence on the {\em sign} of the magnetic field. We find for
fast rotation that positive (negative) Hall parameters essentially reduce
(increase) the stability domain. It is thus concluded that the toroidal field
belts in PNS induced by their differential rotation should have different
amplitudes in both hemispheres which later are frozen in. Due to the effect of
magnetic suppression of the heat conductivity also the brightness of the two
hemispheres should be different. As a possible example for our scenario the
isolated neutron star RBS 1223 is considered which has been found to exhibit
different X-ray brightness at both hemispheres.


title:
Parallelism of quantum computations from prequantum classical
  statistical field theory (PCSFT)

abstract:
  This paper is devoted to such a fundamental problem of quantum computing as
quantum parallelism. It is well known that quantum parallelism is the basis of
the ability of quantum computer to perform in polynomial time computations
performed by classical computers for exponential time. Therefore better
understanding of quantum parallelism is important both for theoretical and
applied research, cf. e.g. David Deutsch \cite{DD}. We present a realistic
interpretation based on recently developed prequantum classical statistical
field theory (PCSFT). In the PCSFT-approach to QM quantum states (mixed as well
as pure) are labels of special ensembles of classical fields. Thus e.g. a
single (!) ``electron in the pure state'' $\psi$ can be identified with a
special `` electron random field,'' say $\Phi_\psi(\phi).$ Quantum computer
operates with such random fields. By one computational step for e.g. a Boolean
function $f(x_1,...,x_n)$ the initial random field $\Phi_{\psi_0}(\phi)$ is
transformed into the final random field $\Phi_{\psi_f}(\phi)$ ``containing all
values'' of $f.$ This is the objective of quantum computer's ability to operate
quickly with huge amounts of information -- in fact, with classical random
fields.


title:
Modified Kolmogorov Wave Turbulence in QCD matched onto "Bottom-up"
  Thermalization

abstract:
  We investigate modification of Kolmogorov wave turbulence in QCD calculating
gluon spectra as functions of time in the presence of a low energy source which
feeds in energy density in the infrared region at a time-dependent rate. Then
considering the picture of saturation constraints as has been constructed in
the "bottom-up" thermalization approach we revisit that picture for RHIC
center-mass energy, $W = 130 {GeV}$, and also extend it to LHC center-mass
energy, $W = 5500 {GeV}$, thus for two cases having an opportunity to calculate
the equilibration time, $tau_{eq|therm}$, of the gluon system produced in a
central heavy ion collision at mid-rapidity region. Thereby, at RHIC and LHC
energies we can match the equilibration time, obtained from the late stage
gluon spectrum of the modified Kolmogorov wave turbulence, onto that of the
"bottom-up" thermalization and other evolutional approaches as well. In
addition, from the revised "bottom-up" approach we find the gluon liberation
coefficient to be on the average, $c = 0.81 - 1.06$ at RHIC and $c = 0.50 -
0.56$ at LHC. We also present other phenomenological estimates of $tau_{therm}$
which, at QCD realistic couplings, yield $0.45fm - 0.65fm < tau_{therm} <
0.97fm - 2.72fm$ at RHIC and $0.31fm - 0.40fm < tau_{therm} < 0.86fm - 2.04fm$
at LHC, both reflecting the original and modified Kolmogorov wave turbulent
scenarios. In the latter case, at certain conditions, taking also into account
both very small and realistic couplings we give estimates - $0.65fm <
tau_{therm} < 1.29fm$ at RHIC and $0.52fm < tau_{therm} < 1.16fm$ at LHC, as
well as at realistic couplings we find $0.53 < tau_{therm} < 0.7fm$ at RHIC and
$0.41 < tau_{therm} < 0.65fm$ at LHC.


title:
Comment on "Quantum and Classical Glass Transitions in
  LiHo$_{x}$Y$_{1-x}$F$_4$" by C. Ancona-Torres, D.M. Silevitch, G. Aeppli, and
  T. F. Rosenbaum, Phys. Rev. Lett. 101, 057201 (2008)

abstract:
  We show in this comment that the claim by Ancona-Torres et al. of an
equilibrium quantum or classical phase transition in the LiHo$_x$Y$_{1-x}$F$_4$
system is not supported by a rigorous scaling analysis.


title:
Resonant electron heating and molecular phonon cooling in single
  C$_{60}$ junctions

abstract:
  We study heating and heat dissipation of a single \c60 molecule in the
junction of a scanning tunneling microscope (STM) by measuring the electron
current required to thermally decompose the fullerene cage. The power for
decomposition varies with electron energy and reflects the molecular resonance
structure. When the STM tip contacts the fullerene the molecule can sustain
much larger currents. Transport simulations explain these effects by molecular
heating due to resonant electron-phonon coupling and molecular cooling by
vibrational decay into the tip upon contact formation.


title:
On flows associated to Sobolev vector fields in Wiener spaces: an
  approach \`a la DiPerna-Lions

abstract:
  In this paper we extend the DiPerna-Lions theory on ODEs with Sobolev vector
fields to the setting of abstract Wiener spaces.


title: On the need for a global academic internet platform

abstract:
  The article collects arguments for the necessity of a global academic
internet platform, which is organized as a kind of ``global scientific
parliament''. With such a constitution educational and research institutions
will have direct means for communicating scientific results, as well as a
platform for representing academia and scientific life in the public.


title:
Discovery of a Young, Energetic 70.5 ms Pulsar Associated with the TeV
  Gamma-ray Source HESS J1837-069

abstract:
  We report the discovery of 70.5 ms pulsations from the X-ray source AX
J1838.0-0655 using the Rossi X-ray Timing Explorer (RXTE). PSR J1838-0655 is a
rotation-powered pulsar with spin-down luminosity Edot = 5.5e36 ergs/s,
characteristic age tau = P/2Pdot = 23 kyr, and surface dipole magnetic field
strength Bs = 1.9e12 G. It coincides with an unresolved INTEGRAL source and the
extended TeV source HESS J1837-069. At an assumed distance of 6.6 kpc by
association with an adjacent massive star cluster, the efficiency of PSR
J1838-0655 converting spin-down luminosity to radiation is 0.8% for the 2-10
keV ASCA flux, 9% for the 20-300 keV INTEGRAL flux and ~3% for the >200 GeV
emission of HESS J1837-069, making it a plausible power source for the latter.
A Chandra X-ray observation resolves AX J1838.0-0655 into a bright point source
surrounded by a ~2' diameter, centrally peaked nebula. The spectra of the
pulsar and nebula are each well fitted by power laws, with photon indices Gamma
= 0.5(0.3-0.7) and Gamma = 1.6(1.1-2.0), respectively. The 2-10 keV X-ray
luminosities of the pulsar and nebula are L(PSR) = 4.6e34 d(6.6)^2 ergs/s and
L(PWN) = 5.2e33 d(6.6)^2 ergs/s. A second X-ray source adjacent to the TeV
emission, AX J1837.3-0652, is resolved into an apparent pulsar/PWN; it may also
contribute to HESS J1837-069. The star cluster RSGC1 may have given birth to
one or both pulsars, while fueling TeV emission from the extended PWN with
target photons for inverse Compton scattering.


title:
Bigravity: a bimetric model of the Universe with variable constants,
  inluding VSL (variable speed of light)

abstract:
  The Universe, far to be homogenous, expands in large empty bubbles of the
large-scale structure, but not in mass concentrations like galaxies, so that
the Robertson-Walker solution does not fit. We suggest that a symmetry breaking
occurred in a distant past, during the radiation-dominated era. Before, the
three-dimensional hypersurface was invariant under the action of O(3) and the
Robertson-Walker metric could be used. But this obliges the so-called constants
and physics, length and time scale factors to be involved through a generalized
gauge process, which is built. The subsequent variation of the speed of light
solves the horizon problem, while the Planck barrier disappears


title: First order phase transitions in nanoscopic systems

abstract:
  The problem of first order phase transitions in nanoscopic systems is
investigated in the framework of Hill's nanothermodynamics. We obtain the
equilibrium conditions and a generalized version of the Clapeyron-Clausius
equation for a nanoscopic system which contains two phases. Our study is
exemplified for the case when one of the phases consists of an ideal gas.


title: Diversification and limited information in the Kelly game

abstract:
  Financial markets, with their vast range of different investment
opportunities, can be seen as a system of many different simultaneous games
with diverse and often unknown levels of risk and reward. We introduce
generalizations to the classic Kelly investment game [Kelly (1956)] that
incorporates these features, and use them to investigate the influence of
diversification and limited information on Kelly-optimal portfolios. In
particular we present approximate formulas for optimizing diversified
portfolios and exact results for optimal investment in unknown games where the
only available information is past outcomes.

categories: q-fin.PM physics.data-an physics.soc-ph stat.AP


title: Dilational Hilbert Scales and Deconvolutional Sharpening

abstract:
  Operationally, index functions of variable Hilbert scales can be viewed as
generators for families of spaces and norms. Using a one parameter family of
index functions based on the dilations of a given index function, a new class
of scales (dilational Hilbert scales (DHS)) is derived which generates new
interpolatory inequalities (dilational interpolatory inequalities (DII)) which
have the ordinary Hilbert scales (OHS) interpolatory inequalities as special
cases. They therefore represent a one-parameter family generalization of OHS,
and are a precise and concise subset of VHS approriate for deriving error
estimates for deconvolution. The role of the Hilbert scales in deriving error
estimates for the approximate solution of inverse problems is discussed along
with an application of DHS to deconvolution sharpening.


title:
Studying Diquark Structure of Heavy Baryons in Relativistic Heavy Ion
  Collisions

abstract:
  We propose the enhancement of $\Lambda_c$ yield in heavy ion collisions at
RHIC and LHC as a novel signal for the existence of diquarks in the strongly
coupled quark-gluon plasma produced in these collisions as well as in the
$\Lambda_c$. Assuming that stable bound diquarks can exist in the quark-gluon
plasma, we argue that the yield of $\Lambda_c$ would be increased by two-body
collisions between $ud$ diquarks and $c$ quarks, in addition to normal
three-body collisions among $u$, $d$ and $c$ quarks. A quantitative study of
this effect based on the coalescence model shows that including the
contribution of diquarks to $\Lambda_c$ production indeed leads to a
substantial enhancement of the $\Lambda_c/D$ ratio in heavy ion collisions.


title: Freedom in Nature

abstract:
  The paper starts with the proposal that the cause of the apparent
insolubility of the free-will problem are several popular but strongly
metaphysical notions and hypotheses. To reduce the metaphysics, some ideas are
borrowed from physics. A concept of event causality is discussed. The
importance of Hume's Principle of Causality is stressed and his Principle of
Causation is weakened. The key concept of the paper, the so-called relative
freedom, is also suggested by physics. It is a kind of freedom that can be
observed everywhere in nature. Turning to biology, incomplete knowledge is
defined for all organisms. They cope with the problem by Popper's trial and
error processes. One source of their success is the relative freedom of choice
from the basic option ranges: mutations, motions and neural connections.
Finally, the conjecture is adopted that communicability can be used as a
criterion of consciousness and free will is defined as a conscious version of
relative freedom. The resulting notion is logically self-consistent and it
describes an observable phenomenon that agrees with our experience.


title: Screening correlators with chiral Fermions

abstract:
  We study screening correlators of quark-antiquark composites at T=2T_c, where
T_c is the QCD phase transition temperature, using overlap quarks in the
quenched approximation of lattice QCD. As the lattice spacing is changed from
1/4T to a=1/6T and 1/8T, we find that screening correlators change little, in
contrast with the situation for other types of lattice fermions. All
correlators are close to the ideal gas prediction at small separations. The
long distance falloff is clearly exponential, showing that a parametrization by
a single screening length is possible at distances z > 1/T. The correlator
corresponding to the thermal vector is close to the ideal gas value at all
distances, whereas that for the thermal scalar deviates at large distances.
This is examined through the screening lengths and momentum space correlators.
There is strong evidence that the screening transfer matrix does not have
reflection positivity.


title:
Baryons in the large N limit of the massive two-dimensional
  Nambu-Jona-Lasinio model

abstract:
  Baryons in the massive Nambu-Jona-Lasinio model in 1+1 dimensions (the
massive chiral Gross-Neveu model) are studied in the limit of an infinite
number of flavors. The baryon mass is evaluated for a wide range of bare
fermion masses and filling fractions, combining analytical asymptotic
expansions with a full numerical Hartree-Fock calculation.


title: Are Flyby Anomalies an ASTG Phenomenon?

abstract:
  This reading expounds with expediency on the recently proposed Azimuthally
Symmetric Theory of Gravitation (ASTG) set-up earlier. At its inspection, it
was demonstrated that the ASTG is capable (among others solar anomalies) of
explaining the precession of the perihelion of solar planets. In the present,
we show that the ASTG is capable of explaining the puzzling observations of
flyby anomalies, i.e. the anomalous asymptotic speed increases of the
osculating hyperbolic speed excess. It is shown that these flyby anomalies
occur naturally in the ASTG. We derive the empirical formula proposed by
Anderson et al. in 2008, which up to now has no physical or foundational basis
except that experience suggest it. If the ASTG model is correct, then for the
first time the Anderson et al. formula is given a physical meaning.


title:
Stability of Five-dimensional Myers-Perry Black Holes with Equal Angular
  Momenta

abstract:
  We study the stability of five-dimensional Myers-Perry black holes with equal
angular momenta which have an enlarged symmetry, U(2). Using this symmetry, we
derive master equations for a part of metric perturbations which are relevant
to the stability. Based on the master equations, we prove the stability of
Myers-Perry black holes under these perturbations. Our result gives a strong
evidence for the stability of Myers-Perry black holes with equal angular
momenta.


title:
Effects of stochastic population fluctuations in two models of
  biological macroevolution

abstract:
  Two mathematical models of macroevolution are studied. These models have
population dynamics at the species level, and mutations and extinction of
species are also included. The population dynamics are updated by difference
equations with stochastic noise terms that characterize population
fluctuations. The effects of the stochastic population fluctuations on
diversity and total population sizes on evolutionary time scales are studied.
In one model, species can make either predator-prey, mutualistic, or
competitive interactions, while the other model allows only predator-prey
interactions. When the noise in the population dynamics is strong enough, both
models show intermittent behavior and their power spectral densities show
approximate $1/f$ fluctuations. In the noiseless limit, the two models have
different power spectral densities. For the predator-prey model, $1/f^2$
fluctuations appears, indicating random-walk like behavior, while the other
model still shows $1/f$ noise. These results indicate that stochastic
population fluctuations may significantly affect long-time evolutionary
dynamics.


title:
1E161348-5055 in the Supernova Remnant RCW 103: A Magnetar in a Young
  Low Mass Binary System?

abstract:
  We suggest that the unique X-ray source 1E161348-5055 at the centre of the
supernova remnant RCW 103 consists of a neutron star in close orbit with a low
mass main sequence star. The time signature of 6.67 hr is interpreted as the
neutron star's spin period. This requires the neutron star to be endowed with a
high surface magnetic field of~10^15 G. Magnetic or/and material (propeller)
torques are able to spin rapidly the young neutron star down to an asymptotic,
equilibrium spin period in close synchronism with the orbital period, similarly
to what happens in the Polar Cataclysmic Variables. 1E161348-5055 could be the
first case of a magnetar born in a young low mass binary system.


title: Different fractal properties of positive and negative returns

abstract:
  We perform an analysis of fractal properties of the positive and the negative
changes of the German DAX30 index separately using Multifractal Detrended
Fluctuation Analysis (MFDFA). By calculating the singularity spectra
$f(\alpha)$ we show that returns of both signs reveal multiscaling. Curiously,
these spectra display a significant difference in the scaling properties of
returns with opposite sign. The negative price changes are ruled by stronger
temporal correlations than the positive ones, what is manifested by larger
values of the corresponding H\"{o}lder exponents. As regards the properties of
dominant trends, a bear market is more persistent than the bull market
irrespective of the sign of fluctuations.


title:
Effects of orbital occupancies on the neutrinoless beta-beta matrix
  element of 76Ge

abstract:
  In this work we use the recently measured neutron occupancies in the 76Ge and
76Se nuclei as a guideline to define the neutron quasiparticle states in the
1p0f0g shell. We define the proton quasiparticles by inspecting the odd-mass
nuclei adjacent to 76Ge and 76Se. We insert the resulting quasiparticles in a
proton-neutron quasiparticle random-phase approximation (pnQRPA) calculation of
the nuclear matrix element of the neutrinoless double beta (0-nu-beta-beta)
decay of 76Ge. A realistic model space and effective microscopic two-nucleon
interactions are used. We include the nucleon-nucleon short-range correlations
and other relevant corrections at the nucleon level. It is found that the
resulting 0-nu-beta-beta matrix element is smaller than in the previous pnQRPA
calculations, and closer to the recently reported shell-model results.


title: Deformed relativistic Hartree-Bogoliubov model for exotic nuclei

abstract:
  A deformed relativistic Hartree-Bogoliubov (DRHB) model is developed aiming
at a proper description of exotic nuclei, particularly deformed ones with large
spatial extension. In order to give an adequate description of both the
contribution of the continuum and the large spatial distribution in exotic
nuclei, the DRHB equations are solved in a Woods-Saxon basis in which the
radial wave functions have proper asymptotic behaviors at large distance from
the nuclear center which is crucial for the formation of halo. The formalism
and the numerical procedure of the DRHB model in a Woods-Saxon basis are
briefly presented.


title: Formation of dispersive hybrid bands at an organic-metal interface

abstract:
  An electronic band with quasi-one dimensional dispersion is found at the
interface between a monolayer of a charge-transfer complex (TTF-TCNQ) and a
Au(111) surface. Combined local spectroscopy and numerical calculations show
that the band results from a complex mixing of metal and molecular states. The
molecular layer folds the underlying metal states and mixes with them
selectively, through the TTF component, giving rise to anisotropic hybrid
bands. Our results suggest that, by tuning the components of such molecular
layers, the dimensionality and dispersion of organic-metal interface states can
be engineered.


title: A gauge invariant infrared stabilization of 3D Yang-Mills gauge theories

abstract:
  We demonstrate that the inversion method can be a very useful tool in
providing an infrared stabilization of 3D gauge theories, in combination with
the mass operator $A^2$ in the Landau gauge. The numerical results will be
unambiguous, since the corresponding theory is ultraviolet finite in
dimensional regularization, making a renormalization scale or scheme obsolete.
The proposed framework is argued to be gauge invariant, by showing that the
nonlocal gauge invariant operator $A^2_{\min}$, which reduces to $A^2$ in the
Landau gauge, could be treated in 3D, in the sense that it is power counting
renormalizable in any gauge. As a corollary of our analysis, we are able to
identify a whole set of powercounting renormalizable nonlocal operators of
dimension two.


title: Finite temperature transport in disordered Heisenberg chains

abstract:
  Using numerical diagonalization techniques, we explore the effect of local
and bond disorder on the finite temperature spin and thermal conductivities of
the one dimensional anisotropic spin-1/2 Heisenberg model. High-temperature
results for local disorder show that the dc conductivties are finite, apart
from the uncorrelated - XY case - where dc transport vanishes. Moreover, at
strong disorder, we find finite dc conductivities at all temperatures $T$,
except T=0. The low frequency conductivities are characterized by a nonanalytic
cusp shape. Similar behavior is found for bond disorder.


title:
The Frobenius action on rank 2 vector bundles over curves in small genus
  and small characteristic

abstract:
  Let X be a general proper and smooth curve of genus 2 (resp. of genus 3)
defined over an algebraically closed field of characteristic p. When 3\leq p
\leq 7, the action of Frobenius on rank 2 semi-stable vector bundles with
trivial determinant is completely determined by its restrictions to the 30
lines (resp. the 126 Kummer surfaces) that are invariant under the action of
some order 2 line bundle over X. Those lines (resp. those Kummer surfaces) are
closely related to the elliptic curves (resp. the abelian varieties of
dimension 2) that appear as the Prym varieties associated to double \'etale
coverings of X. We are therefore able to compute explicit equations of this
action in these cases. We perform some of these computations and draw some
consequences.


title: 174P/Echeclus: a strange case of outburst

abstract:
  Context. More than ten Centaurs are now known to have cometary activity at
large heliocentric distance (i.e. $\simeq$ 5-13 AU). Among these objects,
174P/Echeclus which showed cometary activity at 13 AU from the Sun, is a unique
case, because of: (i) the amplitude of its outburst, (ii) the source of
cometary activity that appears distinct from Echeclus itself.
  Aims. This paper aims at investigating the physical conditions that have led
to this unusual outburst. The purpose is also to quantify this phenomenon and
to provide observational constraints for its modeling.
  Methods. We use observations from different telescopes, performed before,
during, and after the outburst. We performed the main observations on March 23
and 30, 2006, with the 8.2-m ESO Very Large Telescope and FORS 1 instrument.
They consist of visible images and spectra.
  Results. Our main results are: (i) a cometary source distinct from Echeclus
itself that presents a brightness distribution compatible with a diffuse
source; (ii) a total dust production rate Q_dust equal to about 86 kg.s^-1 and
a parameter Afrho equal to 10,000cm; (iii) no emission lines (CN and C_2) can
be detected in the visible range; (iv) the upper limits for the CN and C_2
production rates are about 3.8x10^25 and 10^26 molecules.s^-1 respectively; (v)
we detected no Echeclus' satellite before the outburst up to M_R equal to about
26; (vi) the upper limit for the object generating the coma is about 8 km in
diameter; (vii) and we detected no cometary activity one year later, in March
2007.


title: Rigidity results for some boundary quasilinear phase transitions

abstract:
  We consider a quasilinear equation given in the half-space, i.e. a so called
boundary reaction problem. Our concerns are a geometric Poincar\'e inequality
and, as a byproduct of this inequality, a result on the symmetry of
low-dimensional bounded stable solutions, under some suitable assumptions on
the nonlinearities. More precisely, we analyze the following boundary problem
$$ \left\{\begin{matrix} -{\rm div} (a(x,|\nabla u|)\nabla u)+g(x,u)=0 \qquad
{on $\R^n\times(0,+\infty)$} -a(x,|\nabla u|)u_x = f(u) \qquad{\mbox{on
$\R^n\times\{0\}$}}\end{matrix} \right.$$ under some natural assumptions on the
diffusion coefficient $a(x,|\nabla u|)$ and the nonlinearities $f$ and $g$.
  Here, $u=u(y,x)$, with $y\in\R^n$ and $x\in(0,+\infty)$. This type of PDE can
be seen as a nonlocal problem on the boundary $\partial \R^{n+1}_+$. The
assumptions on $a(x,|\nabla u|)$ allow to treat in a unified way the
$p-$laplacian and the minimal surface operators.


title:
Abundance stratification in Type Ia Supernovae - II: The rapidly
  declining, spectroscopically normal SN 2004eo

abstract:
  The variation of properties of Type Ia supernovae, the thermonuclear
explosions of Chandrasekhar-mass carbon-oxygen white dwarfs, is caused by
different nucleosynthetic outcomes of these explosions, which can be traced
from the distribution of abundances in the ejecta. The composition
stratification of the spectroscopically normal but rapidly declining SN2004eo
is studied performing spectrum synthesis of a time-series of spectra obtained
before and after maximum, and of one nebular spectrum obtained about eight
months later. Early-time spectra indicate that the outer ejecta are dominated
by oxygen and silicon, and contain other intermediate-mass elements (IME),
implying that the outer part of the star was subject only to partial burning.
In the inner part, nuclear statistical equilibrium (NSE) material dominates,
but the production of 56Ni was limited to ~0.43 \pm 0.05 Msun. An innermost
zone containing ~0.25 Msun of stable Fe-group material is also present. The
relatively small amount of NSE material synthesised by SN2004eo explains both
the dimness and the rapidly evolving light curve of this SN.


title:
3D-xy critical properties of YBa2Cu4O8 and magnetic field induced 3D to
  1D crossover

abstract:
  We present reversible magnetization data of a YBa2Cu4O8 single crystal and
analyze the evidence for 3D-xy critical behavior and a magnetic field induced
3D to 1D crossover. Remarkable consistency with these phenomena is observed in
agreement with a magnetic field induced finite size effect, whereupon the
correlation length transverse to the applied magnetic field cannot grow beyond
the limiting magnetic length scale L_H. By applying the appropriate scaling
form we obtain the zero-field critical temperature, the 3D to 1D crossover, the
vortex melting line and the universal ratios of the related scaling variables.
Accordingly there is no continuous phase transition in the (H,T)-plane along
the H_c2-lines as predicted by the mean-field treatment.


title: Decomposition of Complex Reaction Networks into Reactons

abstract:
  The analysis of complex reaction networks is of great importance in several
chemical and biochemical fields (interstellar chemistry, prebiotic chemistry,
reaction mechanism, etc). In this article, we propose to simultaneously refine
and extend for general chemical reaction systems the formalism initially
introduced for the description of metabolic networks. The classical approaches
through the computation of the right null space leads to the decomposition of
the network into complex ``cycles'' of reactions concerned with all
metabolites. We show how, departing from the left null space computation, the
flux analysis can be decoupled into linear fluxes and single loops, allowing a
more refine qualitative analysis as a function of the antagonisms and
connections among these local fluxes. This analysis is made possible by the
decomposition of the molecules into elementary subunits, called "reactons" and
the consequent decomposition of the whole network into simple first order unary
partial reactions related with simple transfers of reactons from one molecule
to another. This article explains and justifies the algorithmic steps leading
to the total decomposition of the reaction network into its constitutive
elementary subpart.


title:
Collective multipole expansions and the perturbation theory in the
  quantum three-body problem

abstract:
  The perturbation theory with respect to the potential energy of three
particles is considered. The first-order correction to the continuum wave
function of three free particles is derived. It is shown that the use of the
collective multipole expansion of the free three-body Green function over the
set of Wigner $D$-functions can reduce the dimensionality of perturbative
matrix elements from twelve to six. The explicit expressions for the
coefficients of the collective multipole expansion of the free Green function
are derived. It is found that the $S$-wave multipole coefficient depends only
upon three variables instead of six as higher multipoles do. The possible
applications of the developed theory to the three-body molecular break-up
processes are discussed.

categories: physics.atom-ph math-ph math.MP physics.chem-ph


title: Quasi-Minimal, Pseudo-Minimal Systems and Dense Orbits

abstract:
  We give a short discussion about a weaker form of minimality (called
quasi-minimality). We call a system quasi-minimal if all dense orbits form an
open set. It is hard to find examples which are not already minimal. Since
elliptic behaviour makes them minimal, these systems are regarded as parabolic
systems. Indeed, we show that a quasi-minimal homeomorphism on a manifold is
not expansive (hyperbolic).


title: From nuclear multifragmentation reactions to supernova explosions

abstract:
  In this talk I discuss properties of hot stellar matter at sub-nuclear
densities which is formed in supernova explosions. I emphasize that
thermodynamic conditions there are rather similar to those created in the
laboratory by intermediate-energy heavy-ion collisions. Theoretical methods
developed for the description of multi-fragment final states in such reactions
can be used also for description of the stellar matter. I present main steps of
the statistical approach to the equation of state and nuclear composition,
dealing with an ensemble of nuclear species instead of one "average" nucleus.


title: Determining the Fractal Dimension of the Interstellar Medium

abstract:
  The Interstellar Medium seems to have an underlying fractal structure, which
can be characterized through its fractal dimension (Df). However, several
factors may affect the determination of Df, such as distortions due to
projection, low image resolution, opacity of the cloud, and low signal-to-noise
ratio. Here we use both simulated clouds and real molecular cloud maps to study
these effects in order to estimate Df in a reliable way. Our results indicate
in a self-consistent way that the fractal dimension of the Interstellar Medium
is in the range 2.6 < Df < 2.8, which is significantly higher than the value Df
= 2.3 usually assumed in the literature.


title: Tate modules of universal p-divisible groups

abstract:
  A p-divisible group over a complete local domain determines a Galois
representation on the Tate module of its generic fibre. We determine the image
of this representation for the universal deformation in mixed characteristic of
a bi-infinitesimal group and for the p-rank strata of the universal deformation
in positive characteristic of an infinitesimal group. The method is a reduction
to the known case of one-dimensional groups by a deformation argument based on
properties of the stratification by Newton polygons.


title:
Quantum-like Representation Algorithm: Transformation of Probabilistic
  Data into vectors on Bloch's Sphere

abstract:
  In this paper we present a simple algorithm for representation of statistical
data of any origin by complex probability amplitudes. Numerical simulation with
Mathematica-6 is performed. The Bloch's sphere is used for visualization of
results of numerical simulation. On the one hand, creation of such a
quantum-like (QL) representation and its numerical approval is an important
step in clarification of extremely complicated interrelation between classical
and quantum randomness. On the other hand, it opens new possibilities for
application the mathematical formalism of QM in other domains of science.


title: Evidence that the Y(4660) is a f_0(980)psi' bound state

abstract:
  We demonstrate that the experimental information currently available for the
Y(4660) is consistent with its being a f_0(980)psi' molecule. Possible
experimental tests of our hypothesis are presented.


title: On inversion formulas and Fibonomial coefficients

abstract:
  A research problem for undergraduates and graduates is being posed as a cap
for the prior antecedent regular discrete mathematics exercises. [Here cap is
not necessarily CAP=Competitive Access Provider, though nevertheless ...] The
object of the cap problem of final interest i.e. array of fibonomial
coefficients and the issue of its combinatorial meaning is to be found in
A.K.Kwa\'sniewski's source papers. The cap problem number seven - still opened
for students has been placed on Mathemagics page of the first author
[http://ii.uwb.edu.pl/akk/dydaktyka/dyskr/dyskretna.htm]. The indicatory
references are to point at a part of the vast domain of the foundations of
computer science in ArXiv affiliation noted as CO.cs.DM. The presentation has
been verified in a tutor system of communication with a couple of intelligent
students. The result is top secret.Temporarily. [Contact: Wikipedia; Theory of
cognitive development].


title:
CMB map derived from the WMAP data through Harmonic Internal Linear
  Combination

abstract:
  We are presenting an Internal Linear Combination (ILC) CMB map, in which the
foreground is reduced through harmonic variance minimization. We have derived
our method by converting a general form of pixel-space approach into spherical
harmonic space, maintaining full correspondence. By working in spherical
harmonic space, spatial variability of linear weights is incorporated in a
self-contained manner and our linear weights are continuous functions of
position over the entire sky. The full correspondence to pixel-space approach
enables straightforward physical interpretation on our approach. In variance
minimization of a linear combination map, the existence of a cross term between
residual foregrounds and CMB makes the linear combination of minimum variance
differ from that of minimum foreground. We have developed an iterative
foreground reduction method, where perturbative correction is made for the
cross term. Our CMB map derived from the WMAP data is in better agreement with
the WMAP best-fit $\Lambda$CDM model than the WMAP team's Internal Linear
Combination map. We find that our method's capacity to clean foreground is
limited by the availability of enough spherical harmonic coefficients of good
Signal-to-Noise Ratio (SNR).


title:
A Vlbi Survey of Weak Extragalactic Radio Sources for the Alignment of
  the Icrf and the Future Gaia Frame

abstract:
  The space astrometry mission GAIA will construct a dense optical QSO-based
celestial reference frame. For consistency between the optical and radio
positions, it will be important to align the GAIA frame and the International
Celestial Reference Frame (ICRF) with the highest accuracy. Currently, it is
found that only 10% of the ICRF sources are suitable to establish this link,
either because they are not bright enough at optical wavelengths or because
they have significant extended radio emission which precludes reaching the
highest astrometric accuracy. In order to improve the situation, we have
initiated a VLBI survey dedicated to finding additional high-quality radio
sources for aligning the two frames. The sample consists of about 450 sources,
typically 20 times weaker than the current ICRF sources, which have been
selected by cross-correlating optical and radio catalogues. The paper presents
the observing strategy and includes preliminary results of observation of 224
of these sources with the European VLBI Network in June 2007.


title:
Analysis and comparison of precise long-term nutation series, strictly
  determined with OCCAM 6.1 VLBI software

abstract:
  The IAU/IUGG Working Group on "Nutation for a non-rigid Earth", led by
V\'eronique Dehant, won the European Descartes Prize in 2003, for its work
developing a new model for the precession and the nutations of the Earth. This
model (MHB2000, Mathews et al. 2002) was adopted by the IAU (International
Astronomical Union) during the General Assembly in Manchester, in 2000. It is
based (i) on some improvements for the precession model (with respect to the
previous one of Lieske et al. 1977) owing to the VLBI technique, and (ii) on a
very accurate nutation model, close to the observations. With this prize, the
Descartes nutation project could offer for international scientists some
grants, to be used for further improvements of the precession-nutation Earth
model. At the IGG (Institute of Geodesy and Geophysics), with the OCCAM 6.1
VLBI analysis software and the best data and models available, we re-analyzed
the whole VLBI sessions available (from 1985 till 2005) solving for the Earth
Orientation Parameters (EOP). In this paper we present the results obtained for
the EOP and more particularly for the nutation series. We compare them with the
other IVS analysis centers results, as well as with the IVS combined EOP series
from the analysis coordinator. The series are in good agreement, except for the
polar motion coordinates that show a shift with respect to the other ones and
that we discuss here. Finally, we analyse the nutation series in the framework
of the free core nutation (FCN) study and modelisation.


title:
Experimental demonstration of multi-watt CW supercontinuum tailoring in
  photonic crystal fibers

abstract:
  We demonstrate experimentally that the spectral broadening of CW
supercontinuum can be controlled by using photonic crystal fibers with two
zero-dispersion wavelengths pumped by an Yb fiber laser at 1064 nm. The
spectrum is bounded by two dispersive waves whose spectral location depends on
the two zero-dispersion wavelengths of the fiber. The bandwidth of the
generated spectrum and the spectral power density may thus be tailored for
particular applications, such as high-resolution optical coherence tomography
or optical spectroscopy.


title: Exponential sums and rank of triple persymmetric matrices over F_2

abstract:
  We obtain using exponential quadratic sums, explicit expressions for the
number of triple persymmetric matrices over F_2 of given rank. (A matrix
[a(i,j)] is persymmetric if a(i,j) = a(r,s) for i+j = r+s)


title: Pseudoknot RNA structures with arc-length $\ge 4$

abstract:
  In this paper we study $k$-noncrossing RNA structures with minimum arc-length
4 and at most $k-1$ mutually crossing bonds. Let ${\sf T}_{k}^{[4]}(n)$ denote
the number of $k$-noncrossing RNA structures with arc-length $\ge 4$ over $n$
vertices. We prove (a) a functional equation for the generating function
$\sum_{n\ge 0}{\sf T}_{k}^{[4]}(n)z^n$ and (b) derive for $k\le 9$ the
asymptotic formula ${\sf T}_{k}^{[4]}(n)\sim c_k n^{-((k-1)^2+(k-1)/2)}
\gamma_k^{-n}$. Furthermore we explicitly compute the exponential growth rates
$\gamma_k^{-1}$ and asymptotic formulas for $4\le k\le 9$.


title: Tops from Light Quarks: Full Mass Dependence at Two-Loops in QCD

abstract:
  I present the two-loop QCD corrections to the production of a massive
quark-anti-quark pair in the massless quark-anti-quark annihilation channel.
The result is obtained as a combination of a deep expansion in the mass around
the high energy limit and of a numerical integration of a system of
differential equations. The primary application of the outcome and developed
methods is top quark pair production at the Large Hadron Collider.


title: On the curvature of the present-day Universe

abstract:
  We discuss the effect of curvature and matter inhomogeneities on the averaged
scalar curvature of the present-day Universe. Motivated by studies of averaged
inhomogeneous cosmologies, we contemplate on the question whether it is
sensible to assume that curvature averages out on some scale of homogeneity, as
implied by the standard concordance model of cosmology, or whether the averaged
scalar curvature can be largely negative today, as required for an explanation
of Dark Energy from inhomogeneities. We confront both conjectures with a
detailed analysis of the kinematical backreaction term and estimate its
strength for a multi-scale inhomogeneous matter and curvature distribution. Our
main result is a formula for the spatially averaged scalar curvature involving
quantities that are all measurable on regional (i.e. up to 100 Mpc) scales. We
propose strategies to quantitatively evaluate the formula, and pinpoint the
assumptions implied by the conjecture of a small or zero averaged curvature. We
reach the conclusion that the standard concordance model needs fine-tuning in
the sense of an assumed equipartition law for curvature in order to reconcile
it with the estimated properties of the averaged physical space, whereas a
negative averaged curvature is favoured, independent of the prior on the value
of the cosmological constant.


title: Layer interdependence of transport in an undoped electron-hole bilayer

abstract:
  The layer interdependence of transport in an undoped electron-hole bilayer
(uEHBL) device was studied as a function of carrier density, interlayer
electric field, and temperature. The uEHBL device consisted of a density
tunable, independently contacted two-dimensional electron gas (2DEG) and
two-dimensional hole gas (2DHG) induced via field effect in distinct GaAs
quantum wells separated by a 30 nm Al$_{0.9}$Ga$_{0.1}$As barrier. Transport
measurements were made simultaneously on each layer using the van der Pauw
method. An increase in 2DHG mobility with increasing 2DEG density was observed,
while the 2DEG mobility showed negligible dependence on the 2DHG density.
Decreasing the interlayer electric-field and thereby increasing interlayer
separation also increased the 2DHG mobility with negligible effects on the 2DEG
mobility. The change in interlayer separation as interlayer electric-field
changed was estimated using 2DHG Coulomb drag measurements. The results were
consistent with mobility of each layer being only indirectly dependent on the
adjacent layer density and dominated by background impurity scattering.
Temperature dependencies were also determined for the resistivity of each
layer.


title: Internal dynamics and particle acceleration in Tycho's SNR

abstract:
  The consequences of a newly suggested value for the SN explosion energy
1.2x10^{51} erg are explored for the case of Tycho's supernova remnant (SNR). A
nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs is employed to
investigate the properties of Tycho's SNR and their correspondence to the
existing experimental data. It is demonstrated that the large mean ratio
between the radii of the contact discontinuity and the forward shock is
consistent with the very effective acceleration of nuclear energetic particles
at the forward shock. It is also argued that consistency of the value E_{sn} =
1.2x10^{51} erg with the gas dynamics, acceleration theory, and the existing
gamma-ray measurements requires the source distance to be greater than 3.3 kpc.
The corresponding ambient gas number density is lower than 0.4 cm^{-3}. Since
the expected gamma-ray flux strongly depends on the source distance,
F_{\gamma}\propto d^{-7}, a future experimental determination of the actual
gamma-ray flux from Tycho's SNR will make it possible to determine the values
of the source distance and of the mean ambient gas density. A simple inverse
Compton model without a dominant population of nuclear CRs is not compatible
with the present upper limit for the gamma-ray emission for any reasonable
ambient interstellar B-field. Given the consistency between acceleration theory
and overall, as well as internal, gas dynamics, a future gamma-ray detection
would make the case for nuclear particle acceleration in Tycho's SNR
incontrovertible in our view.


title: Network of recurrent events for the Olami-Feder-Christensen model

abstract:
  We numerically study the dynamics of a discrete spring-block model introduced
by Olami, Feder and Christensen (OFC) to mimic earthquakes and investigate to
which extent this simple model is able to reproduce the observed spatiotemporal
clustering of seismicty. Following a recently proposed method to characterize
such clustering by networks of recurrent events [Geophys. Res. Lett. {\bf 33},
L1304, 2006], we find that for synthetic catalogs generated by the OFC model
these networks have many non-trivial statistical properties. This includes
characteristic degree distributions -- very similar to what has been observed
for real seismicity. There are, however, also significant differences between
the OFC model and earthquake catalogs indicating that this simple model is
insufficient to account for certain aspects of the spatiotemporal clustering of
seismicity.


title: Collisional Properties of p-Wave Feshbach Molecules

abstract:
  We detected the formation of p-wave Feshbach molecules for all three
combinations of the two lowest atomic spin states of 6Li. By creating a pure
molecular sample in an optical trap, we measured the inelastic collision rates
of p-wave molecules. The elastic collision rate was measured from the
thermalization rate of a breathing mode excited spontaneously upon molecular
formation.