title:
Critical current of spin transfer torque-driven magnetization dynamics
  in magnetic multilayers

abstract:
  The critical current of the spin transfer torque-driven magnetization
dynamics was studied by taking into account both spin pumping and the finite
penetration depth of the transverse spin current. We successfully reproduced
the recent experimental results obtained by Chen et al. [Phys. Rev. B {\bf 74},
144408 (2006)] and found that the critical current remains finite even in the
zero-thickness limit of the free layer. We showed that the remaining value of
the critical current is determined mainly by spin pumping.


title: Clifford Algebra of Nonrelativistic Phase Space and the Concept of Mass

abstract:
  Prompted by a recent demonstration that the structure of a single
quark-lepton generation may be understood via a Dirac-like linearization of the
form p^2+x^2, we analyze the corresponding Clifford algebra in some detail.
After classifying all elements of this algebra according to their U(1) x SU(3)
and SU(2) transformation properties, we identify the element which might be
associated with the concept of lepton mass. This element is then transformed
into a corresponding element for a single coloured quark. It is shown that -
although none of the three thus obtained individual quark mass elements is
rotationally invariant - the rotational invariance of the quark mass term is
restored when the sum over quark colours is performed.


title:
The B3-VLA CSS sample. VII: WSRT Polarisation Observations and the
  Ambient Faraday Medium Properties Revisited

abstract:
  We present new polarisation observations at 13 cm, acquired using the
Westerbork Synthesis Radio Telescope (WSRT), of 65 sources, from the B3-VLA
sample of Compact Steep-Spectrum sources. These new data are combined with our
VLA polarisation data, at 3.6, 6 and, 21 cm, presented in a previous paper. Due
to the multi-channel frequency capabilities of the WSRT, these new 13 cm
observations enable a more reliable determination of integrated Rotation
Measures, and of depolarisation behaviour with wavelength. The new data are
inconsistent with the depolarisation models that we used earlier, and we
propose an alternative model which seems to work properly. We also revise our
previous model for the external Faraday screen, and its dependence on the
source redshift.


title: Magnetic Fluctuations and Turbulence in the Venus Magnetosheath and Wake

abstract:
  Recent research has shown that distinct physical regions in the Venusian
induced magnetosphere are recognizable from the variations of strength and of
wave/fluctuation activity of the magnetic field. In this paper the statistical
properties of magnetic fluctuations are investigated in the Venusian
magnetosheath, terminator, and wake regions. The latter two regions were not
visited by previous missions. We found 1/f fluctuations in the magnetosheath,
large-scale structures near the terminator and more developed turbulence
further downstream in the wake. Location independent short-tailed non-Gaussian
statistics was observed.


title:
Fractional differential equations: alpha-entire solutions, regular and
  irregular singularities

abstract:
  We consider fractional differential equations of order $\alpha \in (0,1)$ for
functions of one independent variable $t\in (0,\infty)$ with the
Riemann-Liouville and Caputo-Dzhrbashyan fractional derivatives. A precise
estimate for the order of growth of $\alpha$-entire solutions is given. An
analog of the Frobenius method for systems with regular singularity is
developed. For a model example of an equation with a kind of an irregular
singularity, a series for a formal solution is shown to be convergent for $t>0$
(if $\alpha$ is an irrational number poorly approximated by rational ones) but
divergent in the distribution sense.


title:
Full Abstraction for a Recursively Typed Lambda Calculus with Parallel
  Conditional

abstract:
  We define the syntax and reduction relation of a recursively typed lambda
calculus with a parallel case-function (a parallel conditional). The reduction
is shown to be confluent. We interpret the recursive types as information
systems in a restricted form, which we call prime systems. A denotational
semantics is defined with this interpretation. We define the syntactical normal
form approximations of a term and prove the Approximation Theorem: The
semantics of a term equals the limit of the semantics of its approximations.
The proof uses inclusive predicates (logical relations). The semantics is
adequate with respect to the observation of Boolean values. It is also fully
abstract in the presence of the parallel case-function.


title: Gravitational Wave Production by Collisions: More Bubbles

abstract:
  We reexamine the production of gravitational waves by bubble collisions
during a first-order phase transition. The spectrum of the gravitational
radiation is determined by numerical simulations using the "envelope
approximation". We find that the spectrum rises as f^3.0 for small frequencies
and decreases as f^-1.0 for high frequencies. Thus, the fall-off at high
frequencies is significantly slower than previously stated in the literature.
This result has direct impact on detection prospects for gravity waves
originating from a strong first-order electroweak phase transition at
space-based interferometers, such as LISA or BBO. In addition, we observe a
slight dependence of the peak frequency on the bubble wall velocity.


title:
Study of reconnection-associated multi-scale fluctuations with Cluster
  and Double Star

abstract:
  The objective of the paper is to asses the specific spectral scaling
properties of magnetic reconnection associated fluctuations/turbulence at the
Earthward and tailward outflow regions observed simultaneously by the Cluster
and Double Star (TC-2) spacecraft on September 26, 2005. Systematic comparisons
of spectral characteristics, including variance anisotropy and scale-dependent
spectral anisotropy features in wave vector space were possible due to the
well-documented reconnection events, occurring between the positions of Cluster
(X = -14--16 $R_e$) and TC-2 (X = -6.6 $R_e$). Another factor of key importance
is that the magnetometers on the spacecraft are similar. The comparisons
provide further evidence for asymmetry of physical processes in
Earthward/tailward reconnection outflow regions. Variance anisotropy and
spectral anisotropy angles estimated from the multi-scale magnetic fluctuations
in the tailward outflow region show features which are characteristic for
magnetohydrodynamic cascading turbulence in the presence of a local mean
magnetic field. The multi-scale magnetic fluctuations in the Earthward outflow
region are exhibiting more power, lack of variance and scale dependent
anisotropies, but also having larger anisotropy angles. In this region the
magnetic field is more dipolar, the main processes driving turbulence are flow
breaking/mixing, perhaps combined with turbulence ageing and non-cascade
related multi-scale energy sources.


title: Detection of C3O in the low-mass protostar Elias 18

abstract:
  We have performed new laboratory experiments which gave us the possibility to
obtain an estimate of the amount of carbon chain oxides (namely C3O2, C2O, and
C3O) formed after irradiation (with 200 keV protons) of pure CO ice, at 16 K.
The analysis of laboratory data indicates that in dense molecular clouds, when
high CO depletion occurs, an amount of carbon chain oxides as high as 2-3x10^-3
with respect to gas phase carbon monoxide can be formed after ion irradiation
of icy grain mantles. Then we have searched for gas phase C2O and C3O towards
ten low-mass young stellar objects. Among these we have detected the C3O line
at 38486.891 MHz towards the low-mass protostar Elias 18. On the basis of the
laboratory results we suggest that in dense molecular clouds gas phase carbon
chain oxides are formed in the solid phase after cosmic ion irradiation of
CO-rich icy mantles and released to the gas phase after desorption of icy
mantles. We expect that the Atacama Large Millimeter Array (ALMA), thanks to
its high sensitivity and resolution, will increase the number of carbon chain
oxides detected in dense molecular clouds.


title: Alexandrov curvature of Kaehler curves

abstract:
  We study the intrinsic geometry of a one-dimensional complex space provided
with a Kaehler metric in the sense of Grauert. We show that if K is an upper
bound for the Gaussian curvature on the regular locus, then the intrinsic
metric has curvature at most K in the sense of Alexandrov.


title: Groupoid representations and modules over the convolution algebras

abstract:
  The classical Serre-Swan's theorem defines a bijective correspondence between
vector bundles and finitely generated projective modules over the algebra of
continuous functions on some compact Hausdorff topological space. We extend
these results to obtain a correspondence between the category of
representations of an etale Lie groupoid and the category of modules over its
convolution algebra that are of finite type and of constant rank. Both of these
constructions are functorially defined on the Morita bicategory of etale Lie
groupoids and the given correspondence represents a natural equivalence between
them.


title: Traveling waves and Compactons in Phase Oscillator Lattices

abstract:
  We study waves in a chain of dispersively coupled phase oscillators. Two
approaches -- a quasi-continuous approximation and an iterative numerical
solution of the lattice equation -- allow us to characterize different types of
traveling waves: compactons, kovatons, solitary waves with exponential tails as
well as a novel type of semi-compact waves that are compact from one side.
Stability of these waves is studied using numerical simulations of the initial
value problem.


title:
A Low-decoding-complexity, Large coding Gain, Full-rate, Full-diversity
  STBC for 4 X 2 MIMO System

abstract:
  This paper proposes a low decoding complexity, full-diversity and full-rate
space-time block code (STBC) for 4 transmit and 2 receive ($4\times 2$)
multiple-input multiple-output (MIMO) systems. For such systems, the best code
known is the DjABBA code and recently, Biglieri, Hong and Viterbo have proposed
another STBC (BHV code) which has lower decoding complexity than DjABBA but
does not have full-diversity like the DjABBA code. The code proposed in this
paper has the same decoding complexity as the BHV code for square QAM
constellations but has full-diversity as well. Compared to the best code in the
DjABBA family of codes, our code has lower decoding complexity, a better coding
gain and hence a better error performance as well. Simulation results
confirming these are presented.


title: Decay of light baryons by soft photon emission

abstract:
  A possible reason for the emission of soft photons in high energy
pp-collisions is discussed.


title: Index and nullity of the Gauss map of the Costa-Hoffman-Meeks surfaces

abstract:
  The aim of this work is to extend the results of S. Nayatani about the index
and the nullity of the Gauss map of the Costa-Hoffman-Meeks surfaces for values
of the genus bigger than 37. That allows us to state that these minimal
surfaces are non degenerate for all the values of the genus in the sense of the
definition of J. Perez and A. Ros.


title:
Stochastic equations with delay: optimal control via BSDEs and regular
  solutions of Hamilton-Jacobi-Bellman equations

abstract:
  We consider an Ito stochastic differential equation with delay, driven by
brownian motion, whose solution, by an appropriate reformulation, defines a
Markov process $X$ with values in a space of continuous functions $\mathbf C$,
with generator $\mathcal L$. We then consider a backward stochastic
differential equation depending on $X$, with unknown processes $(Y,Z)$, and we
study properties of the resulting system, in particular we identify the process
$Z$ as a deterministic functional of $X$. We next prove that the
forward-backward system provides a suitable solution to a class of parabolic
partial differential equations on the space $\mathbf C$ driven by $\mathcal L$,
and we apply this result to prove a characterization of the fair price and the
hedging strategy for a financial market with memory effects. We also include
applications to optimal stochastic control of differential equation with delay:
in particular we characterize optimal controls as feedback laws in terms the
process $X$.


title: Anderson localization: 2-D system in an external magnetic field

abstract:
  The analytical approach developed by us for the calculation of the phase
diagram for the Anderson localization via disorder [J.Phys.: Condens. Matter
14, 13777 (2002)] is generalized here to the case of a strong magnetic field
when $q$ subbands ($q=1,2,3$) arise. It is shown that in a line with the
generally accepted point of view, each subband is characterized by a critical
point with a divergent localization length $\xi$ which reveals anomaly in
energy and disorder parameters. These critical points belong to the phase
coexistence area which cannot be interpreted by means of numerical
investigations. The reason for this is a logical incompleteness of the
algorithm used for analysis of a computer modelling for finite systems in the
parameter range where the finite-size scaling is no longer valid.


title:
Class of exactly solvable SO(n) symmetric spin chains with matrix
  product ground states

abstract:
  We introduce a class of exactly solvable SO(n) symmetric Hamiltonians with
matrix product ground states. For an odd $n\geq 3$ case, the ground state is a
translational invariant Haldane gap spin liquid state; while for an even $n\geq
4$ case, the ground state is a spontaneously dimerized state with twofold
degeneracy. In the matrix product ground states for both cases, we identify a
hidden antiferromagnetic order, which is characterized by nonlocal string order
parameters. The ground-state phase diagram of a generalized SO(n) symmetric
bilinear-biquadratic model is discussed.


title: An analytic study towards instabilities of the glasma

abstract:
  Strong longitudinal color flux fields will be created in the initial stage of
high-energy nuclear collisions. We investigate analytically time evolution of
such boost-invariant color fields from Abelian-like initial conditions, and
next examine stability of the boost-invariant configurations against rapidity
dependent fluctuations. We find that the magnetic background field has an
instability induced by the lowest Landau level whose amplitude grows
exponentially. For the electric background field there is no apparent
instability although pair creations due to the Schwinger mechanism should be
involved.


title: Searches for hyperbolic extra dimensions at the LHC

abstract:
  We investigate a model of large extra dimensions where the internal space has
the geometry of a hyperbolic disc. Compared with the ADD model, this model
provides a more satisfactory solution to the hierarchy problem between the
electroweak scale and the Planck scale, and it also avoids constraints from
astrophysics. In general, a novel feature of this model is that the physical
results depend on the position of the brane in the internal space, and in
particular, the signal almost disappears completely if the brane is positioned
at the center of the disc. Since there is no known analytic form of the
Kaluza-Klein spectrum for our choice of geometry, we obtain a spectrum based on
a combination of approximations and numerical computations. We study the
possible signatures of our model for hadron colliders, especially the LHC,
where the most important processes are the production of a graviton together
with a hadronic jet or a photon. We find that the signals are similar to those
of the ADD model, regarding both qualitative behavior and strength. For the
case of hadronic jet production, it is possible to obtain relatively strong
signals, while for the case of photon production, this is much more difficult.


title: Probing for cosmological parameters with LAMOST measurement

abstract:
  In this paper we study the sensitivity of the Large Sky Area Multi-Object
Fiber Spectroscopic Telescope (LAMOST) project to the determination of
cosmological parameters, employing the Monte Carlo Markov Chains (MCMC) method.
For comparison, we first analyze the constraints on cosmological parameters
from current observational data, including WMAP, SDSS and SN Ia. We then
simulate the 3D matter power spectrum data expected from LAMOST, together with
the simulated CMB data for PLANCK and the SN Ia from 5-year Supernovae Legacy
Survey (SNLS). With the simulated data, we investigate the future improvement
on cosmological parameter constraints, emphasizing the role of LAMOST. Our
results show the potential of LAMOST in probing for the cosmological
parameters, especially in constraining the equation-of-state (EoS) of the dark
energy and the neutrino mass.


title: An adaptive routing strategy for packet delivery in complex networks

abstract:
  We present an efficient routing approach for delivering packets in complex
networks. On delivering a message from a node to a destination, a node forwards
the message to a neighbor by estimating the waiting time along the shortest
path from each of its neighbors to the destination. This projected waiting time
is dynamical in nature and the path through which a message is delivered would
be adapted to the distribution of messages in the network. Implementing the
approach on scale-free networks, we show that the present approach performs
better than the shortest-path approach and another approach that takes into
account of the waiting time only at the neighboring nodes. Key features in
numerical results are explained by a mean field theory. The approach has the
merit that messages are distributed among the nodes according to the
capabilities of the nodes in handling messages.


title: Two-field cosmological models and large-scale cosmic magnetic fields

abstract:
  We consider two different toy cosmological models based on two fields (one
normal scalar and one phantom) realizing the same evolution of the Bang-to-Rip
type. One of the fields (pseudoscalar) interacts with the magnetic field
breaking the conformal invariance of the latter. The effects of the
amplification of cosmic magnetic fields are studied and it is shown that the
presence of such effects can discriminate between different cosmological models
realizing the same global evolution of the universe.


title:
An efficient approach of controlling traffic congestion in scale-free
  networks

abstract:
  We propose and study a model of traffic in communication networks. The
underlying network has a structure that is tunable between a scale-free growing
network with preferential attachments and a random growing network. To model
realistic situations where different nodes in a network may have different
capabilities, the message or packet creation and delivering rates at a node are
assumed to depend on the degree of the node. Noting that congestions are more
likely to take place at the nodes with high degrees in networks with scale-free
character, an efficient approach of selectively enhancing the
message-processing capability of a small fraction (e.g. 3%) of the nodes is
shown to perform just as good as enhancing the capability of all nodes. The
interplay between the creation rate and the delivering rate in determining
non-congested or congested traffic in a network is studied more numerically and
analytically.


title: Detrended fluctuation analysis of traffic data

abstract:
  Different routing strategies may result in different behaviors of traffic on
internet. We analyze the correlation of traffic data for three typical routing
strategies by the detrended fluctuation analysis (DFA) and find that the degree
of correlation of the data can be divided into three regions, i.e., weak,
medium, and strong correlation. The DFA scalings are constants in both the
regions of weak and strong correlation but monotonously increase in the region
of medium correlation. We suggest that it is better to consider the traffic on
complex network as three phases, i.e., the free, buffer, and congestion phase,
than just as two phases believed before, i.e., the free and congestion phase.


title:
Theory of defects in one-dimensional systems: the case of Al in Si
  nanowires

abstract:
  The energetic cost of creating a defect within a host material is given by
the formation energy. Here we present a formulation allowing the calculation of
formation energies in one-dimensional nanostructures, which overcomes the
difficulties involved in defining the chemical potential of the constituent
species and the possible passivation of the surface. We also develop a formula
for the Madelung correction for general dielectric tensors and computational
cell shapes. We apply this formalism to the formation energies of charged Al
impurities in silicon nanowires, obtaining concentrations significantly larger
than in their bulk counterparts.


title:
Darboux transforms and spectral curves of Hamiltonian stationary
  Lagrangian tori

abstract:
  The multiplier spectral curve of a conformal torus in the 4-sphere is
essentially, see arXiv:0712.2311, given by all Darboux transforms of the
conformal torus. In the particular case when the conformal immersion is a
Hamiltonian stationary torus in Euclidean 4-space, the left normal of the
immersion is harmonic, hence we can associate a second Riemann surface: the
eigenline spectral curve of the left normal, as defined by Hitchin. We show
that the multiplier spectral curve of a Hamiltonian stationary torus and the
eigenline spectral curve of its left normal are biholomorphic Riemann surfaces
of genus zero. Moreover, we prove that all Darboux transforms, which arise from
generic points on the spectral curve, are Hamiltonian stationary whereas we
also provide examples of Darboux transforms which are not even Lagrangian.


title: Base-point-free pencils on triple covers of smooth curves

abstract:
  Let $X$ be a smooth algebraic curve. Suppose that there exists a triple
covering $f : X \to Y$ where $Y$ is a smooth algebraic curve. In this paper, we
investigate the existence of morphisms from $X$ to the projective line
$\mathbf{P}^1$ which do not factor through the covering $f$. For this purpose,
we generalize the classical results of Maroni concerning base-point-free
pencils on trigonal curves to the case of triple covers of arbitrary smooth
irrational curves.


title: Tunneling through Color Glass Condensate and True Black Disks

abstract:
  We discover new vacuum solutions of the JIMWLK equation, which correspond to
center of a gauge group. We improve the color glass condensate (CGC) model by
an explicit usage of a density matrix. Studying scattering of CGC states in an
external color field, we observe that an amplitude is naturally expressed via
group characters. We construct an example that shows how new thin effects may
be potentially observed in peripheral collisions. We prove that at any parton
density a gluonic CGC state does not become a true black disk. We find a wave
function of a true black disk and show that it necessarily contains many
quarks. This result corresponds to the necessity of nonvacuum Reggeon loops in
a formation of a true black disk.


title:
Intrinsic spin Hall effect in graphene: Numerical calculations in a
  multi-orbital mode

abstract:
  We study the spin Hall effect (SHE) in graphene using a realistic
multi-orbital tight-binding model that includes the atomic spin-orbit
interaction. The SHE is found to be induced by the spin-dependent Aharonov-Bohm
phase. In the metallic case, the calculated values for the spin Hall
conductivity (SHC) are much smaller than the quantized Hall conductivity for
realistic parameter values of metallic graphene. In the insulating case,
quantization of the SHC is violated due to the multi-orbital effect. The
present study suggests that the SHE in a honeycomb lattice is enhanced by
chemical doping, such as the substitution of carbon atoms with boron atoms.


title: Spin-Polarized STM for a Kondo adatom

abstract:
  We investigate the bias dependence of the tunneling conductance between a
spin-polarized (SP) scanning tunneling microscope (STM) tip and the surface
conduction states of a normal metal with a Kondo adatom. Quantum interference
between tip-host metal and tip-adatom-host metal conduction paths is studied in
the full range of the Fano parameter $q$. The spin-polarized STM gives rise to
a splitting of the Kondo peak and asymmetry in the zero-bias anomaly depending
on the lateral tip-adatom distance. For increasing lateral distances, the Kondo
peak-splitting shows a strong suppression and the spin-polarized conductance
exhibits the standard Fano-Kondo profile.


title: Scaling law for topologically ordered systems at finite temperature

abstract:
  Understanding the behaviour of topologically ordered lattice systems at
finite temperature is a way of assessing their potential as fault-tolerant
quantum memories. We compute the natural extension of the topological
entanglement entropy for T > 0, namely the subleading correction
$I_{\textrm{topo}}$ to the area law for mutual information. Its dependence on T
can be written, for Abelian Kitaev models, in terms of information-theoretic
functions and readily identifiable scaling behaviour, from which the interplay
between volume, temperature, and topological order, can be read. These
arguments are extended to non-Abelian quantum double models, and numerical
results are given for the $D(S_3)$ model, showing qualitative agreement with
the Abelian case.


title:
A unified approach to split absorbing boundary conditions for nonlinear
  Schr\"{o}dinger equations

abstract:
  An efficient method is proposed for numerical solutions of nonlinear
Schr\"{o}dinger equations in an unbounded domain. Through approximating the
kinetic energy term by a one-way equation and uniting it with the potential
energy equation, absorbing boundary conditions are designed to truncate the
unbounded domain, which are in nonlinear form and can perfectly absorb the
waves outgoing from the truncated domain. We examine the stability of the
induced initial boundary value problems defined on the computational domain
with the boundary conditions by a normal mode analysis. Numerical examples are
given to illustrate the stable and tractable advantages of the method.


title:
AGILE and Swift simultaneous observations of the blazar S50716+714
  during the bright flare of October 2007

abstract:
  We present the results of a series of optical, UV, X-ray and gamma-ray
observations of the BL Lac object S50716+714 carried out by the Swift and AGILE
satellites in late 2007 when this blazar was flaring close to its historical
maximum at optical frequencies. We have found that the optical through soft
X-ray emission, likely due to Synchrotron radiation, was highly variable and
displayed a different behavior in the optical UV and soft X-ray bands. The 4-10
keV flux, most probably dominated by the inverse Compton component, remained
instead constant. The counting statistics in the relatively short AGILE GRID
observation was low and consistent with a constant gamma-ray flux at a level
similar to the maximum observed by EGRET. An estimate of the gamma-ray spectral
slope gives a value of the photon index that is close to 2 suggesting that the
peak of the inverse Compton component in the Spectral Energy Distribution (SED)
is within the AGILE energy band. The different variability behavior observed in
different parts of the SED exclude interpretations predicting highly correlated
flux variability like changes of the beaming factor or of the magnetic field in
simple SSC scenarios. The observed SED changes may instead be interpreted as
due to the sum of two SSC components, one of which is constant while the other
is variable and with a systematically higher synchrotron peak energy.


title:
Large-scale magnetic fields from inflation due to Chern-Simons-like
  effective interaction

abstract:
  We discuss the generation of large-scale magnetic fields due to the breaking
of the conformal invariance in the electromagnetic field through the $CPT$-even
dimension-six Chern-Simons-like effective interaction with a fermion current in
inflationary cosmology. It is shown that the magnetic fields on 1Mpc scale with
the field strength of $\sim 10^{-9}$G at the present time can be generated even
for the scale of the effective interaction being the Planck scale.


title: Spiraling spectra of geodesic lines in negatively curved manifolds

abstract:
  Given a negatively curved geodesic metric space M, we study the asymptotic
penetration behaviour of geodesic lines of M in small neighbourhoods of closed
geodesics and of other compact convex subsets of M. We define a spiraling
spectrum which gives precise information on the asymptotic spiraling lengths of
geodesic lines around these objects. We prove analogs of the theorems of
Dirichlet, Hall and Cusick in this context. As a consequence, we obtain
Diophantine approximation results of real numbers, complex numbers, or elements
of the Heisenberg group by irrational quadratic ones.


title: Modified Sonine approximation for granular binary mixtures

abstract:
  We evaluate in this work the hydrodynamic transport coefficients of a
granular binary mixture in $d$ dimensions. In order to eliminate the observed
disagreement (for strong dissipation) between computer simulations and
previously calculated theoretical transport coefficients for a monocomponent
gas, we obtain explicit expressions of the seven Navier-Stokes transport
coefficients with the use of a new Sonine approach in the Chapman-Enskog
theory. Our new approach consists in replacing, where appropriate in the
Chapman-Enskog procedure, the Maxwell-Boltzmann distribution weight function
(used in the standard first Sonine approximation) by the homogeneous cooling
state distribution for each species. The rationale for doing this lies in the
fact that, as it is well known, the non-Maxwellian contributions to the
distribution function of the granular mixture become more important in the
range of strong dissipation we are interested in. The form of the transport
coefficients is quite common in both standard and modified Sonine
approximations, the distinction appearing in the explicit form of the different
collision frequencies associated with the transport coefficients. Additionally,
we numerically solve by means of the direct simulation Monte Carlo method the
inelastic Boltzmann equation to get the diffusion and the shear viscosity
coefficients for two and three dimensions. As in the case of a monocomponent
gas, the modified Sonine approximation improves the estimates of the standard
one, showing again the reliability of this method at strong values of
dissipation.


title: Mathematical Foundation of Quantum Annealing

abstract:
  Quantum annealing is a generic name of quantum algorithms to use
quantum-mechanical fluctuations to search for the solution of optimization
problem. It shares the basic idea with quantum adiabatic evolution studied
actively in quantum computation. The present paper reviews the mathematical and
theoretical foundation of quantum annealing. In particular, theorems are
presented for convergence conditions of quantum annealing to the target optimal
state after an infinite-time evolution following the Schroedinger or stochastic
(Monte Carlo) dynamics. It is proved that the same asymptotic behavior of the
control parameter guarantees convergence both for the Schroedinger dynamics and
the stochastic dynamics in spite of the essential difference of these two types
of dynamics. Also described are the prescriptions to reduce errors in the final
approximate solution obtained after a long but finite dynamical evolution of
quantum annealing. It is shown there that we can reduce errors significantly by
an ingenious choice of annealing schedule (time dependence of the control
parameter) without compromising computational complexity qualitatively. A
review is given on the derivation of the convergence condition for classical
simulated annealing from the view point of quantum adiabaticity using a
classical-quantum mapping.


title:
Concentration and Length Dependence of DNA Looping in Transcriptional
  Regulation

abstract:
  In many cases, transcriptional regulation involves the binding of
transcription factors at sites on the DNA that are not immediately adjacent to
the promoter of interest. This action at a distance is often mediated by the
formation of DNA loops: Binding at two or more sites on the DNA results in the
formation of a loop, which can bring the transcription factor into the
immediate neighborhood of the relevant promoter. Though there have been a
variety of insights into the combinatorial aspects of transcriptional control,
the mechanism of DNA looping as an agent of combinatorial control in both
prokaryotes and eukaryotes remains unclear. We use single-molecule techniques
to dissect DNA looping in the lac operon. In particular, we measure the
propensity for DNA looping by the Lac repressor as a function of the
concentration of repressor protein and as a function of the distance between
repressor binding sites. As with earlier single-molecule studies, we find (at
least) two distinct looped states and demonstrate that the presence of these
two states depends both upon the concentration of repressor protein and the
distance between the two repressor binding sites. We find that loops form even
at interoperator spacings considerably shorter than the DNA persistence length,
without the intervention of any other proteins to prebend the DNA. The
concentration measurements also permit us to use a simple statistical
mechanical model of DNA loop formation to determine the free energy of DNA
looping, or equivalently, the J-factor for looping.


title: Power-law deformation of Wishart-Laguerre ensembles of random matrices

abstract:
  We introduce a one-parameter deformation of the Wishart-Laguerre or chiral
ensembles of positive definite random matrices with Dyson index beta=1,2 and 4.
Our generalised model has a fat-tailed distribution while preserving the
invariance under orthogonal, unitary or symplectic transformations. The
spectral properties are derived analytically for finite matrix size NxM for all
three beta, in terms of the orthogonal polynomials of the standard
Wishart-Laguerre ensembles. For large-N in a certain double scaling limit we
obtain a generalised Marcenko-Pastur distribution on the macroscopic scale, and
a generalised Bessel-law at the hard edge which is shown to be universal. Both
macroscopic and microscopic correlations exhibit power-law tails, where the
microscopic limit depends on beta and the difference M-N. In the limit where
our parameter governing the power-law goes to infinity we recover the
correlations of the Wishart-Laguerre ensembles. To illustrate these findings
the generalised Marcenko-Pastur distribution is shown to be in very good
agreement with empirical data from financial covariance matrices.

categories: math-ph cond-mat.stat-mech hep-th math.MP


title: Front pinning in capillary filling of chemically coated channels

abstract:
  The dynamics of capillary filling in the presence of chemically coated
heterogeneous boundaries is investigated, both theoretically and numerically.
In particular, by mapping the equations of front motion onto the dynamics of a
dissipative driven oscillator, an analytical criterion for front pinning is
derived, under the condition of diluteness of the coating spots. The criterion
is tested against two dimensional Lattice Boltzmann simulations, and found to
provide satisfactory agreement as long as the width of the front interface
remains much thinner than the typical heterogeneity scale of the chemical
coating.


title: On pro-p fundamental groups of marked arithmetic curves

abstract:
  Let k be a global field, p an odd prime number different from char(k) and S,
T disjoint, finite sets of primes of k. Let G_S^T(k)(p)=Gal(k_S^T(p)|k) be the
Galois group of the maximal p-extension of k which is unramified outside S and
completely split at T. We prove the existence of a finite set of primes S_0,
which can be chosen disjoint from any given set M of Dirichlet density zero,
such that the cohomology of G_{S\cup S_0}^T(k)(p) coincides with the etale
cohomology of the associated marked arithmetic curve. In particular, cd
G_{S\cup S_0}^T(k)(p)=2. Furthermore, we can choose S_0 in such a way that
k_{S\cup S_0}^T(p) realizes the maximal p-extension k_\p(p) of the local field
k_\p for all \p\in S\cup S_0, the cup-product H^1(G_{S\cup S_0}^T(k)(p),\F_p)
\otimes H^1(G_{S\cup S_0}^T(k)(p),\F_p) --> H^2(G_{S\cup S_0}^T(k)(p),\F_p) is
surjective and the decomposition groups of the primes in S establish a free
product inside G_{S\cup S_0}^T(k)(p). This generalizes previous work of the
author where similar results were shown in the case T=\emptyset under the
restrictive assumption p\nmid Cl(k) and \zeta_p\notin k.


title: Trends in Fast Feedback R&D

abstract:
  In this paper, starting from the basic description of the equation that
governs the bunch motion and looking at the advances of the technology, three
examples of feedback designs versus technology trend are presented and
discussed. In particular the author compares three digital systems implemented
or proposed for DAFNE and other e+/e- accelerators. Descriptions of some
relevant features are also done. Conclusions on the digital feedback design
trend are reported.


title:
Periodic very high energy gamma-ray emission from LS I +61 303 observed
  with the MAGIC telescope

abstract:
  The MAGIC collaboration has recently reported the discovery of gamma-ray
emission from the binary system LS I +61 303 in the TeV energy region. Here we
present new observational results on this source in the energy range between
300 GeV and 3 TeV. In total 112 hours of data were taken between September and
December 2006 covering 4 orbital cycles of this object. This large amount of
data allowed us to produce an integral flux light curve covering for the first
time all orbital phases of LS I +61 303. In addition, we also obtained a
differential energy spectrum for two orbital phase bins covering the phase
range 0.5<phi<0.6 and 0.6<phi<0.7. The photon index in the two phase bins is
consistent within the errors with an average index
Gamma=2.6+-0.2_{stat}+-0.2_{sys}. LS I +61 303 was found to be variable at TeV
energies on timescales of days. These new MAGIC measurements allowed us to
search for intra-night variability of the VHE emission; however, no evidence
for flux variability on timescales down to 30 minutes was found. To test for
possible periodic structures in the light curve, we apply the formalism
developed by Lomb and Scargle to the LS I +61 303 data taken in 2005 and 2006.
We found the LS I +61 303 data set to be periodic with a period of (26.8+-0.2)
days (with a post-trial chance probability of 10^{-7}), close to the orbital
period.


title:
A Variational Principle for Block Operator Matrices and its Application
  to the Angular Part of the Dirac Operator in Curved Spacetime

abstract:
  The operator associated to the angular part of the Dirac equation in the
Kerr-Newman background metric is a block operator matrix with bounded diagonal
and unbounded off-diagonal entries. The aim of this paper is to establish a
variational principle for block operator matrices of this type and to derive
thereof upper and lower bounds for the angular operator mentioned above. In the
last section, these analytic bounds are compared to numerical values from the
literature.


title:
Turbulent pair separation due to multi scale stagnation point structure
  and its time asymmetry in two-dimensional turbulence

abstract:
  The pair separation model of Goto and Vassilicos (S Goto and J C Vassilicos,
2004, New J.Phys., 6, p.65) is revisited and placed on a sound mathematical
foundation. A DNS of two dimensional homogeneous isotropic turbulence with an
inverse energy cascade and a k^{-5/3} power law is used to investigate
properties of pair separation in two dimensional turbulence. A special focus
lies on the time asymmetry observed between forward and backward separation.
Application of the present model to this data suffers from finite inertial
range effects and thus, conditional averaging on scales rather than on time has
been employed to obtain values for the Richardson constants and their ratio.
The Richardson constants for the forward and backward case are found to be
(1.066 +/- 0.020) and (0.999 +/- 0.007) respectively. The ratio of Richardson
constants for the backwards and forwards case is therefore g_b/g_f = (0.92 +/-
0.03), and hence exhibits a qualitatively different behavior from pair
separation in three dimensional turbulence, where g_b > g_f (J Berg et al.,
2006, Phys.Rev.E, 74(1), p.016304). This indicates that previously proposed
explanations for this time asymmetry based on the strain tensor eigenvalues are
not sufficient to describe this phenomenon in two dimensional turbulence. We
suggest an alternative qualitative explanation based on the time asymmetry
related to the inverse versus forward energy cascade. In two dimensional
turbulence, this asymmetry manifests itself in merging eddies due to the
inverse cascade, leading to the observed ratio of Richardson constants.


title: Charm Mixing and CP-violations - Theory

abstract:
  I begin by commenting on the most recent experimental compilation of D^0
mixing data, emphasizing the so-called 'strong phase' issue. This is followed
by a review of the theory underlying charm mixing, both Standard Model and New
Physics. The mechanism of R_p-violation is used to illustrate the methodology
for New Physics contributions and the relation of this to rare D^0 decays is
pointed out. Finally, I address the subject of CP-violating asymmetries by
describing some suggestions for future experimental studies and a recent
theoretical analysis of New Physics contributions.


title: The challenge of unravelling magnetic properties in LaFeAsO

abstract:
  First principles calculations of magnetic and, to a lesser extent, electronic
properties of the novel LaFeAsO-based superconductors show substantial apparent
controversy, as opposed to most weakly or strongly correlated materials. Not
only do different reports disagree about quantitative values, there is also a
schism in terms of interpreting the basic physics of the magnetic interactions
in this system. In this paper, we present a systematic analysis using four
different first principles methods and show that while there is an unusual
sensitivity to computational details, well-converged full-potential
all-electron results are fully consistent among themselves. What makes results
so sensitive and the system so different from simple local magnetic moments
interacting via basic superexchange mechanisms is the itinerant character of
the calculated magnetic ground state, where very soft magnetic moments and
long-range interactions are characterized by a particular structure in the
reciprocal (as opposed to real) space. Therefore, unravelling the magnetic
interactions in their full richness remains a challenging, but utterly
important task.


title:
Analytical predictions of non-Gaussian distribution parameters for
  stellar plasmas

abstract:
  Stimulated by the recent debate on the physical relevance and on the
predictivity of q-Gaussian formalism, we present specific analytical
expressions for the parameters characterizing non-Gaussian distributions, such
as the nonextensive parameter q, expressions that we have proposed for
different physical systems, an important example being plasmas in the stellar
cores.


title: Prospects in Constraining the Dark Energy Potential

abstract:
  We generalize to non-flat geometries the formalism of Simon et al. (2005) to
reconstruct the dark energy potential. This formalism makes use of quantities
similar to the Horizon-flow parameters in inflation, can, in principle, be made
non-parametric and is general enough to be applied outside the simple, single
scalar field quintessence. Since presently available and forthcoming data do
not allow a non-parametric and exact reconstruction of the potential, we
consider a general parametric description in term of Chebyshev polynomials. We
then consider present and future measurements of H(z), Baryon Acoustic
Oscillations surveys and Supernovae type 1A surveys, and investigate their
constraints on the dark energy potential. We find that, relaxing the flatness
assumption increases the errors on the reconstructed dark energy evolution but
does not open up significant degeneracies, provided that a modest prior on
geometry is imposed. Direct measurements of H(z), such as those provided by BAO
surveys, are crucially important to constrain the evolution of the dark energy
potential and the dark energy equation of state, especially for non-trivial
deviations from the standard LambdaCDM model.


title: Contact switching as a control strategy for epidemic outbreaks

abstract:
  We study the effects of switching social contacts as a strategy to control
epidemic outbreaks. Connections between susceptible and infective individuals
can be broken by either individual, and then reconnected to a randomly chosen
member of the population. It is assumed that the reconnecting individual has no
previous information on the epidemiological condition of the new contact. We
show that reconnection can completely suppress the disease, both by continuous
and discontinuous transitions between the endemic and the infection-free
states. For diseases with an asymptomatic phase, we analyze the conditions for
the suppression of the disease, and show that, even when these conditions are
not met, the increase of the endemic infection level is usually rather small.
We conclude that, within some simple epidemiological models, contact switching
is a quite robust and effective control strategy. This suggests that it may
also be an efficient method in more complex situations.


title: Making research on symmetric functions using MuPAD-Combinat

abstract:
  We present an overview of the implementation of symmetric functions in
MuPAD-Combinat. We also explain how to interface C++ programs with MuPAD in
order to make efficient research during concrete work sessions.


title:
Anisotropic thermodynamic and transport properties of single crystalline
  (Ba$_{1-x}$K$_x$)Fe$_2$As$_2$ (x = 0 and 0.45)

abstract:
  Single crystals of BaFe$_2$As$_2$ and (Ba$_{0.55}$K$_{0.45}$)Fe$_2$As$_2$
have been grown out of excess Sn with 1% or less incorporation of solvent. The
crystals are exceptionally micaceous, are easily exfoliated and can have
dimensions as large as 3 x 3 x 0.2 mm$^3$. The BaFe$_2$As$_2$ single crystals
manifest a structural phase transition from a high temperature tetragonal phase
to a low temperature orthorhombic phase near 85 K and do not show any sign of
superconductivity down to 1.8 K. This transition can be detected in the
electrical resistivity, Hall resistivity, specific heat and the anisotropic
magnetic susceptibility. In the (Ba$_{0.55}$K$_{0.45}$)Fe$_2$As$_2$ single
crystals this transition is suppressed and instead superconductivity occurs
with a transition temperature near 30 K. Whereas the superconducting transition
is easily detected in resistivity and magnetization measurements, the change in
specific heat near $T_c$ is small, but resolvable, giving $\Delta C_p/\gamma
T_c \approx 1$. The application of a 140 kOe magnetic field suppresses $T_c$ by
only $\sim 4$ K when applied along the c-axis and by $\sim 2$ K when applied
perpendicular to the c-axis. The ratio of the anisotropic upper critical
fields, $\gamma = H_{c2}^{\perp c} / H_{c2}^{\| c}$, varies between 2.5 and 3.5
for temperatures down to $\sim 2$ K below $T_c$.


title:
Fluctuation relations in simple examples of non-equilibrium steady
  states

abstract:
  We discuss fluctuation relations in simple cases of non-equilibrium Langevin
dynamics. In particular, we show that close to non-equilibrium steady states
with non-vanishing probability currents some of these relations reduce to a
modified version of the fluctuation-dissipation theorem. The latter may be
interpreted as the equilibrium-like relation in the reference frame moving with
the mean local velocity determined by the probability current.


title:
Faraday Rotation Limits on a Primordial Magnetic Field from WMAP
  Five-Year Data

abstract:
  A primordial magnetic field in the early universe will cause Faraday rotation
of the linear polarization of the cosmic microwave background generated via
Compton scattering at the surface of last scattering. This rotation induces a
non-zero parity-odd (B-mode) polarization component. The Wilkinson Microwave
Anisotropy Probe (WMAP) 5-year data puts an upper limit on the magnitude of the
B-polarization power spectrum; assuming that the B-polarization signal is
totally due to the Faraday rotation effect, the upper limits on the comoving
amplitude of a primordial stochastic magnetic field range from $6 \times
10^{-8}$ to $2 \times 10^{-6}$ G on a comoving length scale of 1 Mpc, depending
on the power spectrum of the magnetic field.


title: Gas and dust mass in the disk around the Herbig Ae star HD169142

abstract:
  We investigate the physical structure of the gas component of the disk around
the pre-main-sequence star HD169142. The 13CO and C18O J=2-1 line emission is
observed from the disk with 1.4'' resolution using the Submillimeter Array. We
adopt the disk physical structure derived from a model which fits the spectral
energy distribution of HD169142. We obtain the full three-dimensional
information on the CO emission with the aid of a molecular excitation and
radiative transfer code. This information is used for the analysis of our
observations and previous 12CO J=2-1 and 1.3 mm continuum data. The disk is in
Keplerian rotation and seen at an inclination close to 13 deg from face-on. We
conclude that the regions traced by different CO isotopologues are distinct in
terms of their vertical location within the disk, their temperature and their
column densities. With the given disk structure, we find that freeze-out is not
efficient enough to remove a significant amount of CO from gas phase. Both
observed lines match the model prediction both in flux and in the spatial
structure of the emission. Therefore we use our data to derive the 13CO and
C18O mass and consequently the 12CO mass using standard isotopic ratios. We
constrain the total disk gas mass to (0.6-3.0)x10(-2) Msun. Adopting a maximum
dust opacity of 2 cm2 per gram of dust we derive a minimum dust mass of
2.16x10(-4) Msun from the fit to the 1.3 mm data. Comparison of the derived gas
and dust mass shows that the gas to dust mass ratio of 100 is only possible
under the assumption of a dust opacity of 2 cm2/g and 12CO abundance of 10(-4)
with respect to H2. However, our data are also compatible with a gas to dust
ratio of 25, with a dust opacity of 1 cm2/g and 12CO abundance of 2x10(-4).


title: Mock Jacobi forms in basic hypergeometric series

abstract:
  We show that some $q$-series such as universal mock theta functions are
linear sums of theta quotients and mock Jacobi forms of weight 1/2, which
become holomorphic parts of real analytic modular forms when they are
restricted to torsion points and multiplied by suitable powers of $q$. And we
prove that certain linear sums of $q$-series are weakly holomorphic modular
forms of weight 1/2 due to annihilation of mock Jacobi forms or completion by
mock Jacobi forms. As an application, we obtain a relation between the rank and
crank of a partition.


title: Equality of multiplicity free skew characters

abstract:
  In this paper we show that two skew diagrams lambda/mu and alpha/beta can
represent the same multiplicity free skew character [lambda/mu]=[alpha/beta]
only in the the trivial cases when lambda/mu and alpha/beta are the same up to
translation or rotation or if lambda=alpha is a staircase partition
lambda=(l,l-1,...,2,1) and lambda/mu and alpha/beta are conjugate of each
other.


title:
Comparison of 3.6 - 8.0 Micron Spitzer/IRAC Galactic Center Survey Point
  Sources with Chandra X-Ray Point Sources in the Central 40x40 Parsecs

abstract:
  We have studied the correlation between 2357 Chandra X-ray point sources in a
40 x 40 parsec field and ~20,000 infrared sources we observed in the
corresponding subset of our 2 x 1.4 degree Spitzer/IRAC Galactic Center Survey
at 3.6-8.0 um, using various spatial and X-ray hardness thresholds. The
correlation was determined for source separations of less than 0.5", 1" or 2".
Only the soft X-ray sources show any correlation with infrared point sources on
these scales, and that correlation is very weak. The upper limit on hard X-ray
sources that have infrared counterparts is <1.7% (3 sigma). However, because of
the confusion limit of the IR catalog, we only detect IR sources with absolute
magnitudes < ~1. As a result, a stronger correlation with fainter sources
cannot be ruled out. Only one compact infrared source, IRS 13, coincides with
any of the dozen prominent X-ray emission features in the 3 x 3 parsec region
centered on Sgr A*, and the diffuse X-ray and infrared emission around Sgr A*
seems to be anti-correlated on a few-arcsecond scale. We compare our results
with previous identifications of near-infrared companions to Chandra X-ray
sources.


title: Robust plasmon waveguides in strongly-interacting nanowire arrays

abstract:
  Arrays of parallel metallic nanowires are shown to provide a tunable, robust,
and versatile platform for plasmon interconnects, including high-curvature
turns with minimum signal loss. The proposed guiding mechanism relies on gap
plasmons existing in the region between adjacent nanowires of dimers and
multi-wire arrays. We focus on square and circular silver nanowires in silica,
for which excellent agreement between both boundary element method and multiple
multipolar expansion calculations is obtained. Our work provides the tools for
designing plasmon-based interconnects and achieving high degree of integration
with minimum cross talk between adjacent plasmon guides.


title:
Experimental observation of an entire family of four-photon entangled
  states

abstract:
  A single linear optical set-up is used to observe an entire family of
four-photon entangled states. This approach breaks with the inflexibility of
present linear-optical set-ups usually designed for the observation of a
particular multi-partite entangled state only. The family includes several
prominent entangled states that are known to be highly relevant for quantum
information applications.


title: On the space of quantum fields in massive two-dimensional theories

abstract:
  For a large class of integrable quantum field theories we show that the
S-matrix determines a space of fields which decomposes into subspaces labeled,
besides the charge and spin indices, by an integer k. For scalar fields k is
non-negative and is naturally identified as an off-critical extension of the
conformal level. To each particle we associate an operator acting in the space
of fields whose eigenvectors are primary (k=0) fields of the massive theory. We
discuss how the existing results for models as different as Z_n, sine-Gordon or
Ising with magnetic field fit into this classification.


abstract:
  (abridged) The Observatory for Multi-Epoch Gravitational Lens Astrophysics
(OMEGA) is a mission concept for a 1.5-m near-UV through near-IR space
observatory that will be dedicated to frequent imaging and spectroscopic
monitoring of ~100 multiply-imaged active galactic nuclei over the whole sky.
Using wavelength-tailored dichroics with extremely high transmittance,
efficient imaging in six channels will be done simultaneously during each visit
to each target. The separate spectroscopic mode, engaged through a flip-in
mirror, uses an image slicer spectrograph. After a period of many visits to all
targets, the resulting multidimensional movies can then be analyzed to a)
measure the mass function of dark matter substructure; b) measure precise
masses of the accreting black holes as well as the structure of their accretion
disks and their environments over several decades of physical scale; and c)
measure a combination of the local Hubble expansion and cosmological distances
to unprecedented precision.


title: Unitary polarized Fermi gas under adiabatic rotation

abstract:
  We discuss the effect of an adiabatic rotation on the phase separation
between the superfluid and normal component of a trapped polarized Fermi gas at
unitarity and zero temperature, under the assumption that quantized vortices
are not formed. We show that the Chandrasekhar-Clogston limit
$n_{\downarrow}/\n_{\uparrow}$ characterizing the local polarization in the
normal phase at the interface is enhanced by the rotation as a consequence of
the centrifugal effect. The density profiles (local and column integral) of the
two spin species are calculated as a function of the angular velocity for
different values of the polarization. The critical value of the angular
velocity at which the superfluid exhibits a spontaneous quadrupole deformation
is also calculated for the unpolarized case.


title:
The Hot Interstellar Medium in Normal Elliptical Galaxies III: The
  Thermal Structure of the Gas

abstract:
  This is the third paper in a series analyzing X-ray emission from the hot
interstellar medium in a sample of 54 normal elliptical galaxies observed by
Chandra, focusing on 36 galaxies with sufficient signal to compute radial
temperature profiles. We distinguish four qualitatively different types of
profile: positive gradient (outwardly rising), negative gradients (falling),
quasi-isothermal (flat) and hybrid (falling at small radii, then rising). We
measure the mean logarithmic temperature gradients in two radial regions: from
0--2 $J$-band effective radii $R_J$ (excluding the central point source), and
from 2--$4R_J$. We find the outer gradient to be uncorrelated with intrinsic
host galaxy properties, but strongly influenced by the environment: galaxies in
low-density environments tend to show negative outer gradients, while those in
high-density environments show positive outer gradients, suggesting influence
of circumgalactic hot gas. The inner temperature gradient is unaffected by the
environment but strongly correlated with intrinsic host galaxy characteristics:
negative inner gradients are more common for smaller, optically faint, low
radio-luminosity galaxies, whereas positive gradients are found in bright
galaxies with stronger radio sources. There is no evidence for bimodality in
the distribution of inner or outer gradients. We propose three scenarios to
explain the inner temperature gradients: (1) Weak AGN heat the ISM locally,
higher-luminosity AGN heat the system globally through jets inflating cavities
at larger radii; (2) The onset of negative inner gradients indicates a
declining importance of AGN heating relative to other sources, such as
compressional heating or supernovae; (3) The variety of temperature profiles
are snapshots of different stages of a time-dependent flow.


title: A family of transversely nonsimple knots

abstract:
  We apply knot Floer homology to exhibit an infinite family of transversely
nonsimple prime knots starting with $10_{132}$. We also discuss the
combinatorial relationship between grid diagrams, braids, and Legendrian and
transverse knots in standard contact $\mathbb{R}^3$.


title:
The optical spectrum of a large isolated polycyclic aromatic
  hydrocarbon: hexa-peri-hexabenzocoronene, C42H18

abstract:
  The first optical spectrum of an isolated polycyclic aromatic hydrocarbon
large enough to survive the photophysical conditions of the interstellar medium
is reported. Vibronic bands of the first electronic transition of the all
benzenoid polycyclic aromatic hydrocarbon hexa-peri-hexabenzocoronene were
observed in the 4080-4530 Angstrom range by resonant 2-color 2-photon
ionization spectroscopy. The strongest feature at 4264 Angstrom is estimated to
have an oscillator strength of f=1.4x10^-3, placing an upper limit on the
interstellar abundance of this polycyclic aromatic hydrocarbon at 4x10^12
cm^-2, accounting for a maximum of ~0.02% of interstellar carbon. This study
opens up the possibility to rigorously test neutral polycyclic aromatic
hydrocarbons as carriers of the diffuse interstellar bands in the near future.


title:
Hydrodynamic equations of anisotropic, polarized and inhomogeneous
  superfluid vortex tangles

abstract:
  We include the effects of anisotropy and polarization in the hydrodynamics of
inhomogeneous vortex tangles, thus generalizing the well known
Hall-Vinen-Bekarevich-Khalatnikov equations, which do not take them in
consideration. These effects contribute to the mutual friction force ${\bf
F}_{ns}$ between normal and superfluid components and to the vortex tension
force $\rho_s{\bf T}$. These equations are complemented by an evolution
equation for the vortex line density $L$, which takes into account these
contributions. These equations are expected to be more suitable than the usual
ones for rotating counterflows, or turbulence behind a cylinder, or turbulence
produced by a grid of parallel thin cylinders towed across a superfluid,
because in these situations polarization is expected to play a relevant role.


title:
Existence of weak solutions for general nonlocal and nonlinear
  second-order parabolic equations

abstract:
  In this article, we provide existence results for a general class of nonlocal
and nonlinear second-order parabolic equations. The main motivation comes from
front propagation theory in the cases when the normal velocity depends on the
moving front in a nonlocal way. Among applications, we present level-set
equations appearing in dislocations' theory and in the study of Fitzhugh-Nagumo
systems.


title: The outskirts of Cygnus OB2

abstract:
  We investigate the possible existence of an extended halo of early-type stars
around Cygnus OB2, which is hinted at by near-infrared color-color diagrams,
and its relationship to Cygnus OB2 itself, as well as to the nearby association
Cygnus OB9 and to the star forming regions in the Cygnus X North complex. A
total of 96 early-type stars are identified in the targeted region, which
amounts to nearly half of the observed sample. Most of them have featureless
near-infrared spectra as expected from OB stars at the available resolution.
Another 18 stars that display Brackett emission lines can be divided between
evolved massive stars (most likely Be stars) and Herbig Ae/Be stars based on
their infrared excesses. A component associated with Cygnus OB9/NGC 6910 is
clearly identified, as well as an enhancement in the surface density of
early-type stars at Cygnus X North. We also find a field population, consisting
largely of early B giants and supergiants, which is probably the same as
identified in recent studies of the inner 1-degree circle around Cygnus OB2.
The age and large extension of this population discards a direct relationship
with Cygnus OB2 or any other particular association. Earlier claims of the
possible large extent of Cygnus OB2 beyond its central, very massive aggregate
seem to be dismissed by our findings. The existence of a nearly ubiquitous
population of evolved stars with massive precursors suggests a massive star
formation history in Cygnus having started long before the formation of the
currently observed OB associations in the region.


title:
Quantum Chernoff bound as a measure of nonclassicality for one-mode
  Gaussian states

abstract:
  We evaluate a Gaussian distance-type degree of nonclassicality for a
single-mode Gaussian state of the quantum radiation field by use of the
recently discovered quantum Chernoff bound. The general properties of the
quantum Chernoff overlap and its relation to the Uhlmann fidelity are
interestingly illustrated by our approach.


title:
D\'efinition d'une structure adaptative de r\'eseau local sans fil \`a
  consommation optimis\'ee

abstract:
  The strong growth of low rate wireless personal area networks (LR-WPAN),
leads us to consider the autonomy problems, thus node lifetime in a network,
knowing that the power supplies replacement is often difficult to realize. The
inherent mobility in this type of equipment is an essential element. It will
provide routing constraints, so a complex problem to solve. This article
provides work lines to assess the performance of such a network in terms of
energy consumption and mobility. The objectives are contradictory; it will
necessarily find a compromise. In addition, if we want to guarantee a maximum
delay for the transmitted messages, possibility offered by the IEEE 802.15-4
standard, another compromise necessitate a strictly fixed structure and a fully
mobile structure. Therefore, we present a quantization of the energy cost
related to the desired data rate and compared to the sleep duration of nodes in
the network. Then, we open reflexion lines to find the best compromise:
consumption / mobility / guaranteed deadlines, in suggesting an adaptive
network structure from a concept of MANET.


title: Extrapolation of Threshold-Limited Null Measurement Frequencies

abstract:
  The total measurable level of a pathogen is due to many sources, which
produce a variety of pulses, overlapping in time, that rise suddenly and then
decay. What is measured is the level of the total contribution of the sources
at a given time. But since we are only capable of measuring the total level
above some threshold $x_0$, we would like to predict the distribution below
this level. Our principal model assumption is that of the asymptotic
exponential decay of all pulses. We show that this implies a power law
distribution for the frequencies of low amplitude observations. As a
consequence, there is a simple extrapolation procedure for carrying the data to
the region below $x_0$.


title:
\'Evaluation d'une application de transmission d'images m\'edicales avec
  un r\'eseau sans fil

abstract:
  We offer a platform for database consultations and/or biomedical images
exchanges, adapted to the low rate wireless transmission, and intended for
general practitioners or specialists. The goal can be preventive, diagnostic
and therapeutic. it Concerns specialties such as radiology, ultrasound, the
anatomical pathology or endoscopy. The main features required in such a context
are to adjust the data compression of both the specific needs of telemedicine
and limited capabilities of wireless communication networks. We present our
approach in which we have set out criteria on Biomedical images quality,
compressed by the wavelet method to retain all the necessary information for an
accurate diagnosis, and determined the characteristics of a wireless network
with minimal performances for the transmission of these images within
constraints related to the modality and the data flow, in this case Wifi based
on the IEEE 802.11 standard. Our results will assess the capacity of this
standard in terms of speed, to transmit images at a rate of 10 frames per
second. It will be necessary to quantify the amount of information to add to
the image datas to enable a transmission in good conditions and the appropriate
modus operandi.


title:
Identification of community structure in networks with convex
  optimization

abstract:
  We reformulate the problem of modularity maximization over the set of
partitions of a network as a conic optimization problem over the completely
positive cone, converting it from a combinatorial optimization problem to a
convex continuous one. A semidefinite relaxation of this conic program then
allows to compute upper bounds on the maximum modularity of the network. Based
on the solution of the corresponding semidefinite program, we design a
randomized algorithm generating partitions of the network with suboptimal
modularities. We apply this algorithm to several benchmark networks,
demonstrating that it is competitive in accuracy with the best algorithms
previously known. We use our method to provide the first proof of optimality of
a partition for a real-world network.


title: Thermodynamics of Plasmaballs and Plasmarings in 3+1 Dimensions

abstract:
  We study localized plasma configurations in 3+1 dimensional massive field
theories obtained by Scherk-Schwarz compactification of 4+1 dimensional CFT to
predict the thermodynamic properties of localized blackholes and blackrings in
Scherk-Schwarz compactified $AdS_6$ using the AdS/CFT correspondence. We
present an exact solution to the relativistic Navier-Stokes equation in the
thin ring limit of the fluid configuration. We also perform a thorough
numerical analysis to obtain the thermodynamic properties of the most general
solution. Finally we compare our results with the recent proposal for the phase
diagram of blackholes in six flat dimensions and find some similarities but
other differences.


title:
The Stochastic Heat Equation Driven by a Gaussian Noise: germ Markov
  Property

abstract:
  Let $u=\{u(t,x);t \in [0,T], x \in {\mathbb{R}}^{d}\}$ be the process
solution of the stochastic heat equation $u_{t}=\Delta u+ \dot F, u(0,\cdot)=0$
driven by a Gaussian noise $\dot F$, which is white in time and has spatial
covariance induced by the kernel $f$. In this paper we prove that the process
$u$ is locally germ Markov, if $f$ is the Bessel kernel of order $\alpha=2k,k
\in \bN_{+}$, or $f$ is the Riesz kernel of order $\alpha=4k,k \in \bN_{+}$.


title:
Modeling single- and multiple-electron resonances for
  electric-field-sensitive scanning probes

abstract:
  We have developed a modeling method suitable to analyze single- and
multiple-electron resonances detected by electric-field-sensitive scanning
probe techniques. The method is based on basic electrostatics and a numerical
boundary-element approach. The results compare well to approximate analytical
expressions and experimental data.


title:
Collapse of the Electron Gas to Two Dimensions in Density Functional
  Theory

abstract:
  Local and semilocal density-functional approximations for the
exchange-correlation energy fail badly in the zero-thickness limit of a
quasi-two-dimensional electron gas, where the density variation is rapid almost
everywhere. Here we show that a fully nonlocal fifth-rung functional, the
inhomogeneous Singwi-Tosi-Land-Sj\"olander (STLS) approach, which employs both
occupied and unoccupied Kohn-Sham orbitals, recovers the true two-dimensional
STLS limit and appears to be remarkably accurate for any thickness of the slab
(and thus for the dimensional crossover). We also show that this good behavior
is only partly due to the use of the full exact exchange energy.


title: Minimal surfaces in circle bundles over Riemann surfaces

abstract:
  For a compact 3-manifold $M$ which is a circle bundle over a compact Riemann
surface $\Sigma$ with even Euler number $e(M)$, and with a Riemannian metric
compatible with the bundle projection, there exists a compact minimal surface
$S$ in $M$. $S$ is embedded and is a section of the restriction of the bundle
to the complement of a finite number of points in $\Sigma$.


title: Transport equation: extension of classical results for div $b\in$ BMO

abstract:
  We investigate the transport equation: $u_t+b \cdot \nabla u=0$. Our result
improves the criteria on uniqueness of weak solutions, replacing the classical
condition: $\div b \in L_\infty$ by $\div b \in BMO$.


title: Quantum time scales in alpha tunneling

abstract:
  The theoretical treatment of alpha decay by Gamow is revisited by
investigating the quantum time scales in tunneling. The time spent by an alpha
particle in front of the barrier and traversing it before escape is evaluated
using microscopic alpha nucleus potentials. The half-life of a nucleus is shown
to correspond to the time spent by the alpha knocking in front of the barrier.
Calculations for medium and super heavy nuclei show that from a multitude of
available tunneling time definitions, the transmission dwell time gives the
bulk of the lifetime of the decaying state, in most cases.


title:
Effective mapping of spin-1 chains onto integrable fermionic models. A
  study of string and Neel correlation functions

abstract:
  We derive the dominant contribution to the large-distance decay of
correlation functions for a spin chain model that exhibits both Haldane and
Neel phases in its ground state phase diagram. The analytic results are
obtained by means of an approximate mapping between a spin-1 anisotropic
Hamiltonian onto a fermionic model of noninteracting Bogolioubov quasiparticles
related in turn to the XY spin-1/2 chain in a transverse field. This approach
allows us to express the spin-1 string operators in terms of fermionic
operators so that the dominant contribution to the string correlators at large
distances can be computed using the technique of Toeplitz determinants. As
expected, we find long-range string order both in the longitudinal and in the
transverse channel in the Haldane phase, while in the Neel phase only the
longitudinal order survives. In this way, the long-range string order can be
explicitly related to the components of the magnetization of the XY model.
Moreover, apart from the critical line, where the decay is algebraic, we find
that in the gapped phases the decay is governed by an exponential tail
multiplied by algebraic factors. As regards the usual two points correlation
functions, we show that the longitudinal one behaves in a 'dual' fashion with
respect to the transverse string correlator, namely both the asymptotic values
and the decay laws exchange when the transition line is crossed. For the
transverse spin-spin correlator, we find a finite characteristic length which
is an unexpected feature at the critical point. We also comment briefly the
entanglement features of the original system versus those of the effective
model. The goodness of the approximation and the analytical predictions are
checked versus density-matrix renormalization group calculations.

categories: cond-mat.stat-mech cond-mat.str-el hep-th quant-ph


title: Thermalized Non-Equilibrated Matter: Compound Processes and Beyond

abstract:
  A characteristic feature of thermalized non-equilibrated matter is that, in
spite of energy relaxation (thermalization), a phase memory of the way the
strongly interacting many-body system was excited remains. In this contribution
we analyze a low energy evaporating proton data in nucleon induced reactions at
$\simeq$62 MeV incident energy with $^{197}$Au, $^{208}$Pb, $^{209}$Bi and
$^{nat}$U. Our analysis demonstrates that the thermalized non-equilibrated
matter survives a cascade of several evaporating particles. Thus the
experiments show that the effect of the anomalously slow phase relaxation, with
upper limits of the phase relaxation widths in the range 1-10$^{-4}$ eV, is
stable with respect to the multi-step evaporating cascade from the thermalized
compound nuclei. We also briefly mention manifestations and implications of the
thermalized non-equilibrated matter for some other fields.


title:
The mixing time evolution of Glauber dynamics for the mean-field Ising
  model

abstract:
  We consider Glauber dynamics for the Ising model on the complete graph on $n$
vertices, known as the Curie-Weiss model. It is well-known that the mixing-time
in the high temperature regime ($\beta < 1$) has order $n\log n$, whereas the
mixing-time in the case $\beta > 1$ is exponential in $n$. Recently, Levin,
Luczak and Peres proved that for any fixed $\beta < 1$ there is cutoff at time
$[2(1-\beta)]^{-1} n\log n$ with a window of order $n$, whereas the mixing-time
at the critical temperature $\beta=1$ is $\Theta(n^{3/2})$. It is natural to
ask how the mixing-time transitions from $\Theta(n\log n)$ to $\Theta(n^{3/2})$
and finally to $\exp(\Theta(n))$. That is, how does the mixing-time behave when
$\beta=\beta(n)$ is allowed to tend to 1 as $n\to\infty$.
  In this work, we obtain a complete characterization of the mixing-time of the
dynamics as a function of the temperature, as it approaches its critical point
$\beta_c=1$. In particular, we find a scaling window of order $1/\sqrt{n}$
around the critical temperature. In the high temperature regime, $\beta = 1 -
\delta$ for some $0 < \delta < 1$ so that $\delta^2 n \to\infty$ with $n$, the
mixing-time has order $(n/\delta)\log(\delta^2 n)$, and exhibits cutoff with
constant 1/2 and window size $n/\delta$. In the critical window, $\beta = 1\pm
\delta$ where $\delta^2 n$ is O(1), there is no cutoff, and the mixing-time has
order $n^{3/2}$. At low temperature, $\beta = 1 + \delta$ for $\delta > 0$ with
$\delta^2 n \to\infty$ and $\delta=o(1)$, there is no cutoff, and the mixing
time has order $(n/\delta)\exp(({3/4}+o(1))\delta^2 n)$.


title:
Evidence for competition between the superconducting and the pseudogap
  state in (BiPb)_2(SrLa)_2CuO_{6+\delta} from muon-spin rotation experiments

abstract:
  The in-plane magnetic penetration depth \lambda_{ab} in optimally doped
(BiPb)_2(SrLa)_2CuO_{6+\delta} (OP Bi2201) was studied by means of muon-spin
rotation. The measurements of \lambda_{ab}^{-2}(T) are inconsistent with a
simple model of a d-wave order parameter and a uniform quasiparticle weight
around the Fermi surface. The data are well described assuming the angular gap
symmetry obtained in ARPES experiments [Phys. Rev. Lett {\bf 98}, 267004
(2007)], where it was shown that the superconducting gap in OP Bi2201 exists
only in segments of the Fermi surface near the nodes. We find that the
remaining parts of the Fermi surface, which are strongly affected by the
pseudogap state, do not contribute significantly to the superconducting
condensate. Our data provide evidence that high temperature superconductivity
and pseudogap behavior in cuprates are competing phenomena.


title: Topology of the Fermi Surface Beyond the Quantum Critical Point

abstract:
  We examine the nature of phase transitions occurring in strongly correlated
Fermi systems at the quantum critical point (QCP) associated with a divergent
effective mass. Conventional scenarios for the QCP involving collective degrees
of freedom are shown to have serious shortcomings. Working within the original
Landau quasiparticle picture, we propose an alternative topological scenario
for the QCP, in systems that obey standard Fermi liquid (FL) theory in advance
of the QCP. Applying the technique of Poincar\'e mapping, we analyze the
sequence of iterative maps generated by the Landau equation for the
single-particle spectrum at zero temperature. It is demonstrated that the Fermi
surface is subject to rearrangement beyond the QCP. If the sequence of maps
converges, a multi-connected Fermi surface is formed. If it fails to converge,
the Fermi surface swells into a volume that provides a measure of entropy
associated with formation of an exceptional state of the system characterized
by partial occupation of single-particle states and dispersion of their
spectrum proportional to temperature. Based on this dual scenario, the
thermodynamics of Fermi systems beyond the QCP exhibits striking departures
from the predictions of standard FL theory. Mechanisms for the release of the
entropy excess of the exceptional state are discussed.


title: Formation dynamics and distribution function of cities population

abstract:
  From the data analysis we defined distribution function against the
population on the level of various structure units, namely regions, federal
districts and the country on the whole. We have studied peculiarities of the
distribution function deformation due to the structure units' enlargement.
Using the master equation in the continuous approximation, we obtain the
Fokker-Plank equation for the distribution function with symmetric transition
rates. In addition, we offer a model where transitions only between neighbour
states are possible. Moreover in this case it is proposed the in and out
transition probability rate for any states are different We define condition
for the formal equivalence of both models to the problem that is described by
the stochastic differential equation with additive and multiplicative white
noises. We have analyzed the corresponding Fokker-Plank equation in the Ito and
Stratonovich calculus, and obtained a solution of the Tsallis distribution
type. We demonstrate a comparison of theoretical results with those of the data
analysis on the level a cumulative distributions. We have used the maximum
likelihood method for fitting. The obtained results allow us to attribute the
specific value of the Tsallis distribution nonextensivity parameter to the
empiric curves.


title: Absolute Physical Calibration in the Infrared

abstract:
  We determine an absolute calibration for the MIPS 24 microns band and
recommend adjustments to the published calibrations for 2MASS, IRAC, and IRAS
photometry to put them on the same scale. We show that consistent results are
obtained by basing the calibration on either an average A0V star spectral
energy distribution (SED), or by using the absolutely calibrated SED of the sun
in comparison with solar-type stellar photometry (the solar analog method).
After the rejection of a small number of stars with anomalous SEDs (or bad
measurements), upper limits of ~ 1.5% (rms) are placed on the intrinsic
infrared SED variations in both A dwarf and solar-type stars. These types of
stars are therefore suitable as general-purpose standard stars in the infrared.
We provide absolutely calibrated SEDs for a standard zero magnitude A star and
for the sun to allow extending this work to any other infrared photometric
system. They allow the recommended calibration to be applied from 1 to 25
microns with an accuracy of ~2 %, and with even higher accuracy at specific
wavelengths such as 2.2, 10.6, and 24 microns, near which there are direct
measurements. However, we confirm earlier indications that Vega does not behave
as a typical A0V star between the visible and the infrared, making it
problematic as the defining star for photometric systems. The integration of
measurements of the sun with those of solar-type stars also provides an
accurate estimate of the solar SED from 1 through 30 microns, which we show
agrees with theoretical models.


title:
Diagonal free field matrix correlators, global symmetries and giant
  gravitons

abstract:
  We obtain a basis of diagonal free field multi-matrix 2-point correlators in
a theory with global symmetry group G. The operators fall into irreducible
representations of G. This applies for gauge group U(N) at finite N. For
composites made of n fundamental fields, this is expressed in terms of
Clebsch-Gordan coefficients for the decomposition of the n-fold tensor products
of the fundamental field representation in terms of G \times S_n
representations. We use this general construction in the case of the SL(2)
sector of \cN=4 SYM. In this case, by using oscillator constructions, we reduce
the computation of the relevant Clebsch-Gordans coupling infinite dimensional
discrete series irreps of SL(2) to a problem in symmetric groups. Applying
these constructions we write down gauge invariant operators with a Fock space
structure similar to that arising in a large angular momentum limit of
worldvolume excitations of giant gravitons. The Fock space structure emerges
from Clebsch multiplicities of tensor products of symmetric group
representations. We also give the action of the 1-loop dilatation operator of
\cN=4 SYM on this basis of multi-matrix operators.


title: Bitwist 3-manifolds

abstract:
  Our earlier twisted-face-pairing construction showed how to modify an
arbitrary orientation-reversing face-pairing on a faceted 3-ball in a
mechanical way so that the quotient is automatically a closed, orientable
3-manifold. The modifications were, in fact, parametrized by a finite set of
positive integers, arbitrarily chosen, one integer for each edge class of the
original face-pairing. This allowed us to find very simple face-pairing
descriptions of many, though presumably not all, 3-manifolds.
  Here we show how to modify the construction to allow negative parameters, as
well as positive parameters, in the twisted-face-pairing construction. We call
the modified construction the bitwist construction. We prove that all closed
connected orientable 3-manifolds are bitwist manifolds. As with the twist
construction, we analyze and describe the Heegaard splitting naturally
associated with a bitwist description of a manifold.


title: Quantum Stephani Universe in vicinity of the symmetry center

abstract:
  We study a class of spherically symmetric Stephani cosmological models in the
presence of a self-interacting scalar field in both classical and quantum
domains. We discuss the construction of `canonical' wave packets resulting from
the solutions of a class of Wheeler-DeWitt equations in the Stephani Universe.
We suggest appropriate initial conditions which result in wave packets
containing some desirable properties, most importantly good classical and
quantum correspondence. We also study the situation from de-Broglie Bohm
interpretation of quantum mechanics to recover the notion of time and compare
the classical and Bohmian results. We exhibit that the usage of the canonical
prescription and appropriate choices of expansion coefficients result in the
suppression of the quantum potential and coincidence between classical and
Bohmian results. We show that, in some cases, contrary to
Friedmann-Robertson-Walker case, the bound state solutions also exist for all
positive values of the cosmological constant.


title: Error analysis of nuclear mass fits

abstract:
  We discuss the least-square and linear-regression methods, which are relevant
for a reliable determination of good nuclear-mass-model parameter sets and
their errors. In this perspective, we define exact and inaccurate models and
point out differences in using the standard error analyses for them. As an
illustration, we use simple analytic models for nuclear binding energies and
study the validity and errors of models' parameters, and uncertainties of its
mass predictions. In particular, we show explicitly the influence of
mass-number dependent weights on uncertainties of liquid-drop global
parameters.


title: Quasi-stationary Random Overlap Structures and the Continuous Cascades

abstract:
  A random overlap structure (ROSt) is a measure on pairs (X,Q) where X is a
locally finite sequence in the real line with a maximum and Q a positive
semidefinite matrix of overlaps intrinsic to the particles X. Such a measure is
said to be quasi-stationary provided that the joint law of the gaps of X and
overlaps Q is stable under a stochastic evolution driven by a Gaussian sequence
with covariance Q. Aizenman et al. have shown that quasi-stationary ROSts serve
as an important computational tool in the study of the Sherrington-Kirkpatrick
(SK) spin-glass model from the perspective of cavity dynamics and the related
ROSt variational principle for its free energy. In this framework, the Parisi
solution is reflected in the ansatz that the overlap matrix exhibit a certain
hierarchical structure. Aizenman et al. have posed the question of whether the
ansatz could be explained by showing that the only ROSts that are
quasi-stationary in a robust sense are given by a special class of hierarchical
ROSts known as both the Ruelle Probability Cascades as well the GREM. Arguin
and Aizenman have given an affirmative answer in the special case that the set
of values S_Q taken on by the entries of Q is finite. We prove that this result
holds even when |S_Q| is infinite provided that Q satisfies the technical
condition that the closure of S_Q has no limit points from below. This is
relevant to the understanding of the ground states of the SK model, as they
satisfy |S_Q| = infinity.


title: Measurement of the quenching factor of Na recoils in NaI(Tl)

abstract:
  Measurements of the quenching factor for sodium recoils in a 5 cm diameter
NaI(Tl) crystal at room temperature have been made at a dedicated neutron
facility at the University of Sheffield. The crystal has been exposed to 2.45
MeV mono-energetic neutrons generated by a Sodern GENIE 16 neutron generator,
yielding nuclear recoils of energies between 10 and 100 keVnr. A cylindrical
BC501A detector has been used to tag neutrons that scatter off sodium nuclei in
the crystal. Cuts on pulse shape and time of flight have been performed on
pulses recorded by an Acqiris DC265 digitiser with a 2 ns sampling time.
Measured quenching factors of Na nuclei range from 19% to 26% in good agreement
with other experiments, and a value of 25.2 \pm 6.4% has been determined for 10
keV sodium recoils. From pulse shape analysis, the mean times of pulses from
electron and nuclear recoils have been compared down to 2 keVee. The
experimental results are compared to those predicted by Lindhard theory,
simulated by the SRIM Monte Carlo code, and a preliminary curve calculated by
Prof. Akira Hitachi.


title: The Kohn Algorithm on Denjoy-Carleman Classes

abstract:
  The equivalence of the Kohn finite ideal type and the D'Angelo finite type
with the subellipticity of the $\bar\partial$-Neumann problem is extended to
pseudoconvex domains in $C^n$ whose defining function is in a Denjoy-Carleman
quasianalytic class closed under differentiation. The proof involves algebraic
geometry over a ring of germs of Denjoy-Carleman quasianalytic functions that
is not known to be Noetherian and that is intermediate between the ring of
germs of real-analytic functions and the ring of germs of smooth functions. It
is also shown that this type of ring of germs of Denjoy-Carleman functions
satisfies the $\sqrt{acc}$ property, one of the strongest properties a
non-Noetherian ring could possess.


title: Analysis of Social Voting Patterns on Digg

abstract:
  The social Web is transforming the way information is created and
distributed. Blog authoring tools enable users to publish content, while sites
such as Digg and Del.icio.us are used to distribute content to a wider
audience. With content fast becoming a commodity, interest in using social
networks to promote and find content has grown, both on the side of content
producers (viral marketing) and consumers (recommendation). Here we study the
role of social networks in promoting content on Digg, a social news aggregator
that allows users to submit links to and vote on news stories. Digg's goal is
to feature the most interesting stories on its front page, and it aggregates
opinions of its many users to identify them. Like other social networking
sites, Digg allows users to designate other users as ``friends'' and see what
stories they found interesting. We studied the spread of interest in news
stories submitted to Digg in June 2006. Our results suggest that pattern of the
spread of interest in a story on the network is indicative of how popular the
story will become. Stories that spread mainly outside of the submitter's
neighborhood go on to be very popular, while stories that spread mainly through
submitter's social neighborhood prove not to be very popular. This effect is
visible already in the early stages of voting, and one can make a prediction
about the potential audience of a story simply by analyzing where the initial
votes come from.


title: Non-linear index coding outperforming the linear optimum

abstract:
  The following source coding problem was introduced by Birk and Kol: a sender
holds a word $x\in\{0,1\}^n$, and wishes to broadcast a codeword to $n$
receivers, $R_1,...,R_n$. The receiver $R_i$ is interested in $x_i$, and has
prior \emph{side information} comprising some subset of the $n$ bits. This
corresponds to a directed graph $G$ on $n$ vertices, where $i j$ is an edge iff
$R_i$ knows the bit $x_j$. An \emph{index code} for $G$ is an encoding scheme
which enables each $R_i$ to always reconstruct $x_i$, given his side
information. The minimal word length of an index code was studied by
Bar-Yossef, Birk, Jayram and Kol (FOCS 2006). They introduced a graph
parameter, $\minrk_2(G)$, which completely characterizes the length of an
optimal \emph{linear} index code for $G$. The authors of BBJK showed that in
various cases linear codes attain the optimal word length, and conjectured that
linear index coding is in fact \emph{always} optimal.
  In this work, we disprove the main conjecture of BBJK in the following strong
sense: for any $\epsilon > 0$ and sufficiently large $n$, there is an
$n$-vertex graph $G$ so that every linear index code for $G$ requires codewords
of length at least $n^{1-\epsilon}$, and yet a non-linear index code for $G$
has a word length of $n^\epsilon$. This is achieved by an explicit
construction, which extends Alon's variant of the celebrated Ramsey
construction of Frankl and Wilson.
  In addition, we study optimal index codes in various, less restricted,
natural models, and prove several related properties of the graph parameter
$\minrk(G)$.


title: Analogue of Sylvester-Cayley formula for invariants of ternary form

abstract:
  The number $\nu_d(n)$ of linearly independed homogeneous invariants of degree
$n$ for the ternary form of degree $d$ is calculated.


title:
Thermal Conductivity of Thermally-Isolating Polymeric and Composite
  Structural Support Materials Between 0.3 and 4 K

abstract:
  We present measurements of the low-temperature thermal conductivity of a
number of polymeric and composite materials from 0.3 to 4 K. The materials
measured are Vespel SP-1, Vespel SP-22, unfilled PEEK, 30% carbon fiber-filled
PEEK, 30% glass-filled PEEK, carbon fiber Graphlite composite rod, Torlon 4301,
G-10/FR-4 fiberglass, pultruded fiberglass composite, Macor ceramic, and
graphite rod. These materials have moderate to high elastic moduli making them
useful for thermally-isolating structural supports.


title:
Reply to Wernsdorfer's post: "Correspondence on: Quantum interference of
  tunnel trajectories between states of different spin lenght in a dimeric
  molecular nanomagnet"

abstract:
  We present here an exact version of our response (dated April 27) to
Wernsdorfer's correspondence submitted to Nature Physics on March 31, 2008.
After consultation with a referee, Nature Physics chose not publish any part of
this exchange. We would therefore like to point out that our original study has
now been considered favorably by four separate referees chosen by Nature
Physics. Unfortunately, Wernsdorfer subsequently posted two further variations
of his correspondence on this archive (arXiv:0804.1246v1 and
arXiv:0804.1246v2). We note that aspects of the most recent posting (dated
after submission of our response) contradict the version submitted to Nature
Physics. However, none of the revisions add weight to Wernsdorfer's original
correspondence.


title:
Panglossian Prospects for Detecting Neutralino Dark Matter in Light of
  Natural Priors

abstract:
  In most global fits of the constrained minimal supersymmetric model (CMSSM)
to indirect data, the a priori likelihoods of any two points in tan beta are
treated as equal, and the more fundamental mu and B Higgs potential parameters
are fixed by potential minimization conditions. We find that, if instead a flat
("natural")prior measure on mu and B is placed, a strong preference exists for
the focus point region from fits to particle physics and cosmological data. In
particular, we find that the lightest neutralino is strongly favored to be a
mixed bino-higgsino (~10% higgsino). Such mixed neutralinos have large elastic
scattering cross sections with nuclei, leading to extremely promising prospects
for both underground direct detection experiments and neutrino telescopes. In
particular, the majority of the posterior probability distribution falls within
parameter space within an order of magnitude of current direct detection
constraints. Furthermore, neutralino annihilations in the sun are predicted to
generate thousands of neutrino induced muon events per years at IceCube. Thus,
assuming the framework of the CMSSM and using the natural prior measure, modulo
caveats regarding astrophysical uncertainties, we are likely to be living in a
world with good prospects for the direct and indirect detection of neutralino
dark matter.


title:
A characterisation of the Hoffman-Wohlgemuth surfaces in terms of their
  symmetries

abstract:
  For an embedded singly periodic minimal surface M with genus bigger than or
equal to 4 and annular ends, some weak symmetry hypotheses imply its congruence
with one of the Hoffman-Wohlgemuth examples. We give a very geometrical proof
of this fact, along which they come out many valuable clues for the
understanding of these surfaces.


title: On divergence form SPDEs with VMO coefficients

abstract:
  We present several results on solvability in Sobolev spaces $W^{1}_{p}$ of
SPDEs in divergence form in the whole space.


title: On Picture (2+1)-TQFTs

abstract:
  The goal of the paper is an exposition of the simplest $(2+1)$-TQFTs in a
sense following a pictorial approach. In the end, we fell short on details in
the later sections where new results are stated and proofs are outlined.
Comments are welcome and should be sent to the 4th author.


title: A conjecture on the forms of the roots of equations

abstract:
  E30 in the Enestrom index. Translated from the Latin original "De formis
radicum aequationum cuiusque ordinis coniectatio" (1733). For an equation of
degree n, Euler wants to define a "resolvent equation" of degree n-1 whose
roots are related to the roots of the original equation. Thus by solving the
resolvent we can solve the original equation. In sections 2 to 7 he works this
out for quadratic, cubic and biquadratic equations. Apparently he gives a new
method for solving the quartic in section 5. Then in section 8 Euler says that
he wants to try the same approach for solving the quintic equation and general
nth degree equations. In the rest of the paper Euler tries to figure out in
what cases resolvents will work.
  Two references I found useful were Chapter 14, p.p. 106-113 of C. Edward
Sandifer, "The Early Mathematics of Leonhard Euler", published 2007 by The
Mathematical Association of America and Olaf Neumann, "Cyclotomy: from Euler
through Vandermonde to Gauss", p.p. 323-362 in the collection "Leonhard Euler:
Life, Work and Legacy" edited by Bradley and Sandifer, 2007. Stacy Langton has
given a lot of details about Euler's work on the theory of equations, and also
some advice on the translation; of course any mistakes are my own. If Langton
ends up writing anything about Euler' and the theory of equations I would
highly recommend reading it.