title: Conformally flat submanifolds in spheres and integrable systems

abstract:
  E. Cartan proved that conformally flat hypersurfaces in S^{n+1} for n>3 have
at most two distinct principal curvatures and locally envelop a one-parameter
family of (n-1)-spheres. We prove that the Gauss-Codazzi equation for
conformally flat hypersurfaces in S^4 is a soliton equation, and use a dressing
action from soliton theory to construct geometric Ribaucour transforms of these
hypersurfaces. We describe the moduli of these hypersurfaces in S^4 and their
loop group symmetries. We also generalise these results to conformally flat
n-immersions in (2n-2)-spheres with flat normal bundle and constant
multiplicities.


title:
Periodicity of non-central integral arrangements modulo positive
  integers

abstract:
  An integral coefficient matrix determines an integral arrangement of
hyperplanes in R^m. After modulo q reduction, the same matrix determines an
arrangement A_q of "hyperplanes" in Z^m. In the special case of central
arrangements, Kamiya, Takemura and Terao [J. Algebraic Combin., to appear]
showed that the cardinality of the complement of A_q in Z_q^m is a
quasi-polynomial in q. Moreover, they proved in the central case that the
intersection lattice of A_q is periodic from some q on. The present paper
generalizes these results to the case of non-central arrangements. The paper
also studies the arrangement B_m^{[0,a]} of Athanasiadis [J. Algebraic Combin.
Vol.10 (1999), 207-225] to illustrate our results.


title: Many-body treatment of quantum transport through single molecules

abstract:
  We develop a theoretical approach to quantum transport through single
conjugated organic molecules that accurately accounts for all molecular excited
and ground states via a semi-empirical many-body molecular Hamiltonian. We then
calculate the linear and non-linear transport properties of a benzenedithiol
molecule covalently bonded to two gold electrodes at room temperature,
eliminating all free parameters by comparing the calculated thermopower and
linear-conductance with experiment. The resulting `molecular diamond' structure
exhibits experimentally observed many-body effects inaccessible to mean-field
approaches.


title:
New reaction rate for 16O(p,gamma)17F and its influence on the oxygen
  isotopic ratios in massive AGB stars

abstract:
  The 16O(p,gamma)17F reaction rate is revisited with special emphasis on the
stellar temperature range of T=60-100 MK important for hot bottom burning in
asymptotic giant branch (AGB) stars. We evaluate existing cross section data
that were obtained since 1958 and, if appropriate, correct published data for
systematic errors that were not noticed previously, including the effects of
coincidence summing and updated effective stopping powers. The data are
interpreted by using two different models of nuclear reactions, that is, a
potential model and R-matrix theory. A new astrophysical S-factor and
recommended thermonuclear reaction rates are presented. As a result of our
work, the 16O(p,gamma)17F reaction has now the most precisely known rate
involving any target nucleus in the mass A >= 12 range, with reaction rate
errors of about 7% over the entire temperature region of astrophysical interest
(T=0.01-2.5 GK). The impact of the present improved reaction rate with its
significantly reduced uncertainties on the hot bottom burning in AGB stars is
discussed. In contrast to earlier results we find now that there is not clear
evidence to date for any stellar grain origin from massive AGB stars.


title: Uniform value in Dynamic Programming

abstract:
  We consider dynamic programming problems with a large time horizon, and give
sufficient conditions for the existence of the uniform value. As a consequence,
we obtain an existence result when the state space is precompact, payoffs are
uniformly continuous and the transition correspondence is non expansive. In the
same spirit, we give an existence result for the limit value. We also apply our
results to Markov decision processes and obtain a few generalizations of
existing results.


title: (l,k)-Routing on Plane Grids

abstract:
  The packet routing problem plays an essential role in communication networks.
It involves how to transfer data from some origins to some destinations within
a reasonable amount of time. In the $(\ell,k)$-routing problem, each node can
send at most $\ell$ packets and receive at most $k$ packets. Permutation
routing is the particular case $\ell=k=1$. In the $r$-central routing problem,
all nodes at distance at most $r$ from a fixed node $v$ want to send a packet
to $v$. In this article we study the permutation routing, the $r$-central
routing and the general $(\ell,k)$-routing problems on plane grids, that is
square grids, triangular grids and hexagonal grids. We use the
\emph{store-and-forward} $\Delta$-port model, and we consider both full and
half-duplex networks. We first survey the existing results in the literature
about packet routing, with special emphasis on $(\ell,k)$-routing on plane
grids. Our main contributions are the following:
  1. Tight permutation routing algorithms on full-duplex hexagonal grids, and
half duplex triangular and hexagonal grids.
  2. Tight $r$-central routing algorithms on triangular and hexagonal grids.
  3. Tight $(k,k)$-routing algorithms on square, triangular and hexagonal
grids.
  4. Good approximation algorithms (in terms of running time) for
$(\ell,k)$-routing on square, triangular and hexagonal grids, together with new
lower bounds on the running time of any algorithm using shortest path routing.
  These algorithms are all completely distributed, i.e., can be implemented
independently at each node. Finally, we also formulate the $(\ell,k)$-routing
problem as a \textsc{Weighted Edge Coloring} problem on bipartite graphs.


title:
3-loop Yang-Mills Condensate Dark Energy Model And Its Cosmological
  Constraints

abstract:
  This work is a comprehensive investigation of the Yang-Mills condensate (YMC)
dark energy (DE) model, which is extended to include the 3-loop quantum
corrections. We study its cosmic evolution and the possibility of crossing
phantom divide $w=-1$, examine in details the Hubble parameter $H$, the
deceleration parameter $q$, the statefinder diagnosis $(r,s)$, and the
$w-w^\prime$ diagnosis of the model without and with interaction, and compare
our results with other DE models. Besides, by using the observational data of
type Ia supernovae (SNIa), the shift parameter from cosmic microwave background
(CMB), and the baryon acoustic oscillation (BAO) peak from large scale
structures (LSS), we give the cosmological constraints on 3-loop YMC model. It
is found that the model can naturally solve the coincidence problem, and its
prediction of the afore-mentioned parameter is much closer to the $\Lambda$CDM
model than other dynamics DE models; the introduction of the matter-DE
interaction will make the YMC model deviating from the $\Lambda$CDM model, and
will give an equation of state (EOF) crossing -1. Moreover, it is also found
that, to fit the latest SNIa data alone, the $\Lambda$CDM model is slightly
better than the 3-loop YMC model; but in fitting of the combination of SNIa,
CMB and LSS data, the 3-loop YMC model performs better than the $\Lambda$CDM
model.


title:
Tunable hybridization of electronic states of graphene and a metal
  surface

abstract:
  We present an approach to monitor and control the strength of the
hybridization between electronic states of graphene and metal surfaces.
Inspecting the distribution of the $\pi$ band in a high-quality graphene layer
synthesized on Ni(111) by angle-resolved photoemission, we observe a new "kink"
feature which indicates a strong hybridization between $\pi$ and \textit{d}
states of graphene and nickel, respectively. Upon deposition and gradual
intercalation of potassium atoms into the graphene/Ni(111) interface, the
"kink" feature becomes less pronounced pointing at potassium mediated
attenuation of the interaction between the graphene and the substrate.


title: On the string solution in the SUSY - Skyrme model

abstract:
  In this paper, we have found the string solution in the SUSY Skyrme model.
Moreover, the mechanics of decay of SUSY - string was discussed.


title: Double species condensate with tunable interspecies interactions

abstract:
  We produce Bose-Einstein condensates of two different species, $^{87}$Rb and
$^{41}$K, in an optical dipole trap in proximity of interspecies Feshbach
resonances. We discover and characterize two Feshbach resonances, located
around 35 and 79 G, by observing the three-body losses and the elastic
cross-section. The narrower resonance is exploited to create a double species
condensate with tunable interactions. Our system opens the way to the
exploration of double species Mott insulators and, more in general, of the
quantum phase diagram of the two species Bose-Hubbard model.


title:
Coexistence of anomalous field effect and mesoscopic conductance
  fluctuations in granular aluminium

abstract:
  We perform electrical field effect measurements at 4 K on insulating granular
aluminium thin films. When the samples size is reduced below 100 micrometers,
reproducible and stable conductance fluctuations are seen as a function of the
gate voltage. Our results suggest that these fluctuations reflect the
incomplete self-averaging of largely distributed microscopic resistances. We
also study the anomalous field effect (conductance dip) already known to exit
in large samples and its slow conductance relaxation in the presence of the
conductance fluctuations. Within our measurements accuracy, the two phenomena
appear to be independent of each other, like two additive contributions to the
conductance. We discuss the possible physical meaning of this independence and
in particular whether or not this observation is in favor of an electron glass
interpretation of slow conductance anomaly relaxations.


title:
Galactic Cosmic Rays - Clouds Effect and Bifurcation Model of the Earth
  Global Climate. Part 1. Theory

abstract:
  Based on theoretical and experimental consideration of the first (the Twomey
effect) and second indirect aerosol effects the quasianalytic description of
physical connection between the galactic cosmic rays intensity and the Earth's
cloud cover is obtained. It is shown that the basic equation of the Earth's
climate energy-balance model is described by the bifurcation equation (with
respect to the temperature of the Earth's surface) in the form of assembly-type
catastrophe with the two governing parameters defining the variations of
insolation and Earth's magnetic field (or the galactic cosmic rays intensity in
the atmosphere), respectively. The principle of hierarchical climatic models
construction, which consists in the structural invariance of balance equations
of these models evolving on different time scales, is described.


title:
Galactic Cosmic Rays - Clouds Effect and Bifurcation Model of the Earth
  Global Climate. Part 2. Comparison of Theory with Experiment

abstract:
  The solution of energy-balance model of the Earth global climate and the
EPICA Dome C and Vostok experimental data of the Earth surface
palaeotemperature evolution over past 420 and 740 kyr are compared. In the
framework of proposed bifurcation model (i) the possible sharp warmings of the
Dansgaard-Oeschger type during the last glacial period due to stochastic
resonance is theoretically argued; (ii) the concept of climatic sensitivity of
water in the atmosphere, whose temperature instability has the form of
so-called hysteresis loop, is proposed, and based of this concept the time
series of global ice volume over the past 1000 kyr, which is in good agreement
with the time series of delta O-18 concentration in the sea sediments, is
obtained; (iii) the so-called "CO2 doubling" problem is discussed


title:
Potts models in the continuum. Uniqueness and exponential decay in the
  restricted ensembles

abstract:
  In this paper we study a continuum version of the Potts model. Particles are
points in R^d, with a spin which may take S possible values, S being at least
3. Particles with different spins repel each other via a Kac pair potential. In
mean field, for any inverse temperature there is a value of the chemical
potential at which S+1 distinct phases coexist. For each mean field pure phase,
we introduce a restricted ensemble which is defined so that the empirical
particles densities are close to the mean field values. Then, in the spirit of
the Dobrushin Shlosman theory, we get uniqueness and exponential decay of
correlations when the range of the interaction is large enough. In a second
paper, we will use such a result to implement the Pirogov-Sinai scheme proving
coexistence of S+1 extremal DLR measures.


title:
AKK Update: Improvements from New Theoretical Input and Experimental
  Data

abstract:
  We perform a number of improvements to the previous AKK extraction of
fragmentation functions for $\pi^\pm$, $K^\pm$, $p/\bar{p}$, $K_S^0$ and
$\Lambda/\bar{\Lambda}$ particles at next-to-leading order. Inclusive hadron
production measurements from $pp(\bar{p})$ reactions at BRAHMS, CDF, PHENIX and
STAR are added to the data sample. We use the charge-sign asymmetry of the
produced hadrons in $pp$ reactions to constrain the valence quark
fragmentations. Data from $e^+ e^-$ reactions in regions of smaller $x$ and
lower $\sqrt{s}$ are added. Hadron mass effects are treated for all observables
and, for each particle, the hadron mass used for the description of the $e^+
e^-$ reaction is fitted. The baryons' fitted masses are found to be only around
1% above their true masses, while the values of the mesons' fitted masses have
the correct order of magnitude. Large $x$ resummation is applied in the
coefficient functions of the $e^+ e^-$ reactions, and also in the evolution of
the fragmentation functions, which in most cases results in a significant
reduction of the minimized $\chi^2$. To further exploit the data, all published
normalization errors are incorporated via a correlation matrix.


title: An update on semisimple quantum cohomology and F-manifolds

abstract:
  In the first section of this note we show that the Theorem 1.8.1 of
Bayer--Manin ([BaMa]) can be strengthened in the following way: {\it if the
even quantum cohomology of a projective algebraic manifold $V$ is generically
semi--simple, then $V$ has no odd cohomology and is of Hodge--Tate type.} In
particular, this addressess a question in [Ci].
  In the second section, we prove that {\it an analytic (or formal)
supermanifold $M$ with a given supercommutative associative
$\Cal{O}_M$--bilinear multiplication on its tangent sheaf $\Cal{T}_M$ is an
$F$--manifold in the sense of [HeMa], iff its spectral cover as an analytic
subspace of the cotangent bundle $T^*_M$ is coisotropic of maximal dimension.}
This answers a question of V. Ginzburg.
  Finally, we discuss these results in the context of mirror symmetry and
Landau--Ginzburg models for Fano varieties.


title: Min- and Max- Relative Entropies and a New Entanglement Monotone

abstract:
  Two new relative entropy quantities, called the min- and max-relative
entropies, are introduced and their properties are investigated. The well-known
min- and max- entropies, introduced by Renner, are obtained from these. We
define a new entanglement monotone, which we refer to as the max-relative
entropy of entanglement, and which is an upper bound to the relative entropy of
entanglement. We also generalize the min- and max-relative entropies to obtain
smooth min- and max- relative entropies. These act as parent quantities for the
smooth Renyi entropies, and allow us to define the analogues of the mutual
information, in the Smooth Renyi Entropy framework. Further, the spectral
divergence rates of the Information Spectrum approach are shown to be obtained
from the smooth min- and max-relative entropies in the asymptotic limit.


title: Hausdorff property of the Neron models of Green, Griffiths and Kerr

abstract:
  We prove the Hausdorff property of the Neron modle of the family of
intermediate Jacobians which is recently defined by Green, Griffiths and Kerr
assuming that the divisor at infinity is smooth. Using their result, this
implies in this case the analyticity of the closure of the zero locus of an
admissible normal function. The last assertion is also obtained by Brosnan and
Pearlstein generalizing their method in the curve case.


title: Testing chiral effective theory with quenched lattice QCD

abstract:
  We investigate two-point correlation functions of left-handed currents
computed in quenched lattice QCD with the Neuberger-Dirac operator. We consider
two lattice spacings a~0.09,0.12 fm and two different lattice extents L~ 1.5,
2.0 fm; quark masses span both the p- and the epsilon-regimes. We compare the
results with the predictions of quenched chiral perturbation theory, with the
purpose of testing to what extent the effective theory reproduces quenched QCD
at low energy. In the p-regime we test volume and quark mass dependence of the
pseudoscalar decay constant and mass; in the epsilon-regime, we investigate
volume and topology dependence of the correlators. While the leading order
behaviour predicted by the effective theory is very well reproduced by the
lattice data in the range of parameters that we explored, our numerical data
are not precise enough to test next-to-leading order effects.


title:
Multifractal detrended cross-correlation analysis for two nonstationary
  signals

abstract:
  It is ubiquitous in natural and social sciences that two variables, recorded
temporally or spatially in a complex system, are cross-correlated and possess
multifractal features. We propose a new method called multifractal detrended
cross-correlation analysis (MF-DXA) to investigate the multifractal behaviors
in the power-law cross-correlations between two records in one or higher
dimensions. The method is validated with cross-correlated 1D and 2D binomial
measures and multifractal random walks. Application to two financial time
series is also illustrated.


title:
An explicit construction of a maximal relative symplectic packing of the
  Clifford torus

abstract:
  In this paper we present an explicit construction of a relative symplectic
packing. This confirms the sharpness of the upper bound for the relative
packing of a ball into the pair (CP^2, T^2) of the standard complex projective
plane and the Clifford torus, obtained by Biran and Cornea.


title: Interplay of Spin and Orbital Angular Momentum in the Proton

abstract:
  We derive the consequences of the Myhrer-Thomas explanation of the proton
spin problem for the distribution of orbital angular momentum on the valence
and sea quarks. After QCD evolution these results are found to be in very good
agreement with both recent lattice QCD calculations and the experimental
constraints from Hermes and JLab.


title: Negative conductance in driven Josephson junctions

abstract:
  We investigate an optimal regime of negative-valued conductance, emerging in
a resistively and capacitively shunted Josephson junction, which is driven
simultaneously by both, a time-periodic (ac) and a constant (dc) current. We
analyze the current-voltage characteristics in the regime of absolute negative
conductance. We additionally explore the stability of the negative response
with respect to the ac-current frequency.


title: $R^2$ curvature-squared corrections on drag force

abstract:
  The effect of finite-coupling corrections to the drag force on a moving heavy
quark in the Super Yang-Mills plasma is investigated. These corrections are
related to curvature-squared corrections in the corresponding gravity dual. The
results are compared with the dual gauge theory. It is shown that
curvature-squared corrections affect the drag force. It is shown that
corrections to the drag force depend on the velocity of the heavy quark. The
diffusion coefficient of non-relativistic heavy quarks is calculated from the
drag force. In addition, we also calculate the drag force on a moving heavy
quark in the Gauss-Bonnet background.


title:
q-Pascal's triangle and irreducible representations of the braid group
  B_3 in arbitrary dimension

abstract:
  We construct a [(n+1)/2]+1 parameters family of irreducible representations
of the Braid group B_3 in arbitrary dimension n\in N, using a q-deformation of
the Pascal triangle. This construction extends in particular results by
S.P.Humphries [8], who constructed representations of the braid group B_3 in
arbitrary dimension using the classical Pascal triangle. E.Ferrand [7] obtained
an equivalent representation of B_3 by considering two special operators in the
space C^n[X]. Slightly more general representations were given by I.Tuba and
H.Wenzl [11]. They involve [(n+1)/2] parameters (and also use the classical
Pascal triangle). The latter authors also gave the complete classification of
all simple representations of B_3 for dimension n\leq 5. Our construction
generalize all mentioned results and throws a new light on some of them. We
also study the irreducibility and the equivalence of the representations.
  In [17] we establish the connection between the constructed representation of
the braid group B_3 and the highest weight modules of U(sl_2) and quantum group
U_q(sl_2).


title:
Measurement of the ttbar production cross section in ppbar collisions at
  sqrt{s} = 1.96 TeV

abstract:
  We measure the ttbar production cross section in ppbar collisions at
sqrt{s}=1.96 TeV in the lepton+jets channel. Two complementary methods
discriminate between signal and background, b-tagging and a kinematic
likelihood discriminant. Based on 0.9 fb-1 of data collected by the D0 detector
at the Fermilab Tevatron Collider, we measure sigma_ttbar=7.62+/-0.85 pb,
assuming the current world average m_t=172.6 GeV. We compare our cross section
measurement with theory predictions to determine a value for the top quark mass
of 170+/-7 GeV.


title:
Detection of interaction-induced nonlocal effects using perfectly
  transmitting nanostructures

abstract:
  We consider one-dimensional transport through an interacting region in series
with a point-like one-body scatterer. When the conductance of the interacting
region is perfect, independently of the interaction strength, a nonlocal
interaction effect yields a total conductance of the composed system that
depends on the interaction strength and is lower than the transmission of the
one-body scatterer. This qualitative nonlocal effect allows to probe the
dressing cloud of an interacting system by ideal noninteracting leads. The
conductance correction increases with the strength of the interaction and the
reflection of the one-body scatterer (attaining relative changes >50%), and
decreases with the distance between the interacting region and the one-body
scatterer. Scaling laws are obtained and possible experimental realizations are
suggested.


title: Functoriality of the canonical fractional Galois ideal

abstract:
  The fractional Galois ideal of [Victor P. Snaith, Stark's conjecture and new
Stickelberger phenomena, Canad. J. Math. 58 (2) (2006) 419--448] is a
conjectural improvement on the higher Stickelberger ideals defined at negative
integers, and is expected to provide non-trivial annihilators for higher
K-groups of rings of integers of number fields. In this article, we extend the
definition of the fractional Galois ideal to arbitrary (possibly infinite and
non-abelian) Galois extensions of number fields under the assumption of Stark's
conjectures, and prove naturality properties under canonical changes of
extension. We discuss applications of this to the construction of ideals in
non-commutative Iwasawa algebras.


title: Interaction-induced beats of Friedel oscillations in quantum wires

abstract:
  We analyze the spectrum of electron density oscillations in an interacting
one-dimensional electron system with an impurity. The system's inhomogeneity is
characterized by different values of Fermi wave vectors $k_F=k_{L/R}$ on
left/right side of the scatterer, leading to a Landauer dipole formation. We
demonstrate, that while in the noninteracting system the Friedel oscillations
possess only one periodicity related to the local $k_F$, say $k_L$ on the left
side, the interplay of the interactions and the Landauer dipole generates an
additional peak in the spectrum of density oscillations at the counterpart
$k_R$. Being only present in correlated systems, the position and shape of this
spectral feature, which in coordinate space is observable as a beating pattern
in the Friedel oscillations, reveals many important details about the nature of
interactions. Thus it has a potential to become an investigation tool in
condensed matter physics.


title: On the measurements regarding random observables

abstract:
  Both classical and respectively quantum observables can be modeled as
somewhat similar examples of random variables. In such a model the associated
measurements preserve the values spectrum of an observable but change the
corresponding probabilistic weights (probability density or respectively the
wave function). Such a model ensures theoretical estimations for predicted
errors specific to the mean values as well as to the fluctuations of both types
of observables. The model stands out of ourdays prevalent opinion that
measurement theories must be depicted in entirely different manners in the
classical respectively quantum cases.


title: Magneto-static vortices in two dimensional Abelian gauge theories

abstract:
  We study the existence of vortices of the Klein-Gordon-Maxwell equations in
the two dimensional case. In particular we find sufficient conditions for the
existence of vortices in the magneto-static case, i.e when the electric
potential $\phi=0$. This result, due to the lack of suitable embedding theorems
for the vector potential $\A$ is achieved with the help of a penalization
method.


title:
Representations of the braid group B_n and the highest weight modules of
  U(sl_{n-1}) and U_q(sl_{n-1})

abstract:
  In [1] we have constructed a [n+1/2]+1 parameters family of irreducible
representations of the Braid group B_3 in arbitrary dimension using a
$q-$deformation of the Pascal triangle. This construction extends in particular
results by S.P. Humphries (2000), who constructed representations of the braid
group B_3 in arbitrary dimension using the classical Pascal triangle. E.
Ferrand (2000) obtained an equivalent representation of B_3 by considering two
special operators in the space ${\mathbb C}^n[X].$ Slightly more general
representations were given by I. Tuba and H. Wenzl (2001). They involve [n+1/2]
parameters (and also use the classical Pascal's triangle). The latter authors
also gave the complete classification of all simple representations of $B_3$
for dimension $n\leq 5$. Our construction generalize all mentioned results and
throws a new light on some of them. We also study the irreducibility and
equivalence of the constructed representations.
  In the present article we show that all representations constructed in [1]
may be obtained by taking exponent of the highest weight modules of U(sl}_2 and
U_q(sl_2). We generalize these connections between the representation of the
braid group $B_n$ and the highest weight modules of the U_q(sl_{n-1}) for
arbitrary} n using the well-known reduced Burau representation.


title:
Classification of topological insulators and superconductors in three
  spatial dimensions

abstract:
  We systematically study topological phases of insulators and superconductors
(SCs) in 3D. We find that there exist 3D topologically non-trivial insulators
or SCs in 5 out of 10 symmetry classes introduced by Altland and Zirnbauer
within the context of random matrix theory. One of these is the recently
introduced Z_2 topological insulator in the symplectic symmetry class. We show
there exist precisely 4 more topological insulators. For these systems, all of
which are time-reversal (TR) invariant in 3D, the space of insulating ground
states satisfying certain discrete symmetry properties is partitioned into
topological sectors that are separated by quantum phase transitions. 3 of the
above 5 topologically non-trivial phases can be realized as TR invariant SCs,
and in these the different topological sectors are characterized by an integer
winding number defined in momentum space. When such 3D topological insulators
are terminated by a 2D surface, they support a number (which may be an
arbitrary non-vanishing even number for singlet pairing) of Dirac fermion
(Majorana fermion when spin rotation symmetry is completely broken) surface
modes which remain gapless under arbitrary perturbations that preserve the
characteristic discrete symmetries. In particular, these surface modes
completely evade Anderson localization. These topological phases can be thought
of as 3D analogues of well known paired topological phases in 2D such as the
chiral p-wave SC. In the corresponding topologically non-trivial and
topologically trivial 3D phases, the wavefunctions exhibit markedly distinct
behavior. When an electromagnetic U(1) gauge field and fluctuations of the gap
functions are included in the dynamics, the SC phases with non-vanishing
winding number possess non-trivial topological ground state degeneracies.


title:
Successive phase transitions to antiferromagnetic and weak-ferromagnetic
  long-range orders in quasi-one-dimensional antiferromagnet Cu$_3$Mo$_2$O$_9$

abstract:
  Investigation of the magnetism of Cu$_3$Mo$_2$O$_9$ single crystal, which has
antiferromagnetic (AF) linear chains interacting with AF dimers, reveals an AF
second-order phase transition at $T_{\rm N} = 7.9$ K. Although weak
ferromagnetic-like behavior appears at lower temperatures in low magnetic
fields, complete remanent magnetization cannot be detected down to 0.5 K.
However, a jump is observed in the magnetization below weak ferromagnetic (WF)
phase transition at $T_{\rm c} \simeq 2.5$ K when a tiny magnetic field along
the a axis is reversed, suggesting that the coercive force is very weak. A
component of magnetic moment parallel to the chain forms AF long-range order
(LRO) below $T_{\rm N}$, while a perpendicular component is disordered above
$T_{\rm c}$ at zero magnetic field and forms WF-LRO below $T_{\rm c}$.
Moreover, the WF-LRO is also realized with applying magnetic fields even
between $T_{\rm c}$ and $T_{\rm N}$. These results are explainable by both
magnetic frustration among symmetric exchange interactions and competition
between symmetric and asymmetric Dzyaloshinskii-Moriya exchange interactions.


title:
Simultaneous cooling and entanglement of mechanical modes of a
  micromirror in an optical cavity

abstract:
  Laser cooling of a mechanical mode of a resonator by the radiation pressure
of a detuned optical cavity mode has been recently demonstrated by various
groups in different experimental configurations. Here we consider the effect of
a second mechanical mode with a close, but different resonance frequency. We
show that the nearby mechanical resonance is simultaneously cooled by the
cavity field, provided that the difference between the two mechanical
frequencies is not too small. When this frequency difference becomes smaller
than the effective mechanical damping of the secondary mode, the two cooling
processes interfere destructively and cavity cooling is suppressed in the limit
of identical mechanical frequencies. We show that also the entanglement
properties of the steady state of the tripartite system crucially depend upon
on the difference between the two mechanical frequencies. If the latter is
larger than the effective damping of the second mechanical mode, the state
shows fully tripartite entanglement and each mechanical mode is entangled with
the cavity mode. If instead the frequency difference is smaller, the steady
state is a two-mode biseparable state, inseparable only when one splits the
cavity mode from the two mechanical modes. In this latter case, the
entanglement of each mechanical mode with the cavity mode is extremely fragile
with respect to temperature.


title:
The random energy model in a magnetic field and joint source-channel
  coding

abstract:
  We demonstrate that there is an intimate relationship between the magnetic
properties of Derrida's random energy model (REM) of spin glasses and the
problem of joint source--channel coding in Information Theory. In particular,
typical patterns of erroneously decoded messages in the coding problem have
``magnetization'' properties that are analogous to those of the REM in certain
phases, where the non--uniformity of the distribution of the source in the
coding problem, plays the role of an external magnetic field applied to the
REM. We also relate the ensemble performance (random coding exponents) of joint
source--channel codes to the free energy of the REM in its different phases.


title: 12CO(3-2) Emission in Spiral Galaxies: Warm Molecular Gas in Action?

abstract:
  Using the APEX sub-millimeter telescope we have investigated the 12CO(3-2)
emission in five face-on nearby barred spiral galaxies, where three of them are
high surface brightness galaxies (HSBs) lying at the Freeman limit, and two are
low surface brightness galaxies (LSBs). We have positive detections for two of
three HSB spirals and non-detections for the LSBs. For the galaxies with
positive detection (NGC0521 and PGC070519), the emission is confined to their
bulges, with velocity dispersions of ~90 and ~73 km/s and integrated
intensities of 1.20 and 0.76 K/km/s, respectively. For the non-detections, the
estimated upper limit for the integrated intensity is ~0.54 K/km/s. With these
figures we estimate the H2 masses as well as the atomic-to-molecular mass
ratios. Although all the galaxies are barred, we observe 12CO(3-2) emission
only for galaxies with prominent bars. We speculate that bars could dynamically
favor the 12CO(3-2) emission, as a second parameter after surface brightness.
Therefore, secular evolution could play a major role in boosting collisional
transitions of molecular gas, such as 12CO(3-2), especially in LSBs.


title:
SiO line emission from C-type shock waves : interstellar jets and
  outflows

abstract:
  We study the production of SiO in the gas phase of molecular outflows,
through the sputtering of Si--bearing material in refractory grain cores, which
are taken to be olivine; we calculate also the rotational line spectrum of the
SiO. The sputtering is driven by neutral particle impact on charged grains, in
steady--state C-type shock waves, at the speed of ambipolar diffusion. The
emission of the SiO molecule is calculated by means of an LVG code. A grid of
models has been generated. We compare our results with those of an earlier
study (Schilke et al. 1997). Improvements in the treatment of the coupling
between the charged grains and the neutral fluid lead to narrower shock waves
and lower fractions of Si being released into the gas phase. More realistic
assumptions concerning the initial fractional abundance of O2 lead to SiO
formation being delayed, so that it occurs in the cool, dense postshock flow.
Good agreement is obtained with recent observations of SiO line intensities in
the L1157 and L1448 molecular outflows. The inferred temperature, opacity, and
SiO column density in the emission region differ significantly from those
estimated by means of LVG `slab' models. The fractional abundance of SiO is
deduced. Observed line profiles are wider than predicted and imply multiple,
unresolved shock regions within the beam.


title:
Negative Differential Resistance Induced by Mn Substitution at
  SrRuO3/Nb:SrTiO3 Schottky Interfaces

abstract:
  We observed a strong modulation in the current-voltage characteristics of
SrRuO$_3$/Nb:SrTiO$_3$ Schottky junctions by Mn substitution in SrRuO$_3$,
which induces a metal-insulator transition in bulk. The temperature dependence
of the junction ideality factor indicates an increased spatial inhomogeneity of
the interface potential with substitution. Furthermore, negative differential
resistance was observed at low temperatures, indicating the formation of a
resonant state by Mn substitution. By spatially varying the position of the Mn
dopants across the interface with single unit cell control, we can isolate the
origin of this resonant state to the interface SrRuO$_3$ layer. These results
demonstrate a conceptually different approach to controlling interface states
by utilizing the highly sensitive response of conducting perovskites to
impurities.


title: Hole Localization in One-Dimensional Doped Anderson-Hubbard Model

abstract:
  We study the interplay of disorder and correlation in the one-dimensional
hole-doped Hubbard-model with disorder (Anderson-Hubbard model) by using the
density-matrix renormalization group method. Concentrating on the doped-hole
density profile, we find in a large $U/t$ regime that the clean system exhibits
a simple fluid-like behavior whereas finite disorders create locally Mott
regions which expand their area with increasing the disorder strength contrary
to the ordinary sense. We propose that such an anomalous Mott phase formation
assisted by disorder is observable in atomic Fermi gases by setup of the box
shape trap.


title: Critical tunneling currents in the regime of bilayer excitons

abstract:
  We have investigated the tunneling properties of an electron double quantum
well system where the lowest Landau level of each quantum well is half filled.
This system is expected to be a Bose condensate of excitons. Our four-terminal
dc measurements reveal a nearly vanishing interlayer voltage and the existence
of critical tunneling currents which depend on the strength of the condensate
state.


title: Correlations of eigenvalues and Riemann zeros

abstract:
  We present a new approach to obtaining the lower order terms for
$n$-correlation of the zeros of the Riemann zeta function. Our approach is
based on the `ratios conjecture' of Conrey, Farmer, and Zirnbauer. Assuming the
ratios conjecture we prove a formula which explicitly gives all of the lower
order terms in any order correlation. Our method works equally well for random
matrix theory and gives a new expression, which is structurally the same as
that for the zeta function, for the $n$-correlation of eigenvalues of matrices
from U(N).


title:
A pedestrian's view on interacting particle systems, KPZ universality,
  and random matrices

abstract:
  These notes are based on lectures delivered by the authors at a Langeoog
seminar of SFB/TR12 "Symmetries and universality in mesoscopic systems" to a
mixed audience of mathematicians and theoretical physicists. After a brief
outline of the basic physical concepts of equilibrium and nonequilibrium
states, the one-dimensional simple exclusion process is introduced as a
paradigmatic nonequilibrium interacting particle system. The stationary measure
on the ring is derived and the idea of the hydrodynamic limit is sketched. We
then introduce the phenomenological Kardar-Parisi-Zhang (KPZ) equation and
explain the associated universality conjecture for surface fluctuations in
growth models. This is followed by a detailed exposition of a seminal paper of
Johansson that relates the current fluctuations of the totally asymmetric
simple exclusion process (TASEP) to the Tracy-Widom distribution of random
matrix theory. The implications of this result are discussed within the
framework of the KPZ conjecture.

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


title: Multiplication for solutions of the equation $\grad{f} = M\grad{g}$

abstract:
  Linear first order systems of partial differential equations of the form
$\nabla f = M\nabla g,$ where $M$ is a constant matrix, are studied on vector
spaces over the fields of real and complex numbers, respectively. The
Cauchy--Riemann equations belong to this class. We introduce a bilinear
$*$-multiplication on the solution space, which plays the role of a nonlinear
superposition principle, that allows for algebraic construction of new
solutions from known solutions. The gradient equations $\nabla f = M\nabla g$
constitute only a simple special case of a much larger class of systems of
partial differential equations which admit a bilinear multiplication on the
solution space, but we prove that any gradient equation has the exceptional
property that the general analytic solution can be expressed through power
series of certain simple solutions, with respect to the $*$-multiplication.


title: Towards fault-tolerant quantum computing with trapped ions

abstract:
  Today ion traps are among the most promising physical systems for
constructing a quantum device harnessing the computing power inherent in the
laws of quantum physics. The standard circuit model of quantum computing
requires a universal set of quantum logic gates for the implementation of
arbitrary quantum operations. As in classical models of computation, quantum
error correction techniques enable rectification of small imperfections in gate
operations, thus allowing for perfect computation in the presence of noise. For
fault-tolerant computation, it is commonly believed that error thresholds
ranging between 10^-4 and 10^-2 will be required depending on the noise model
and the computational overhead for realizing the quantum gates. Up to now, all
experimental implementations have fallen short of these requirements. Here, we
report on a Molmer-Sorensen type gate operation entangling ions with a fidelity
of 99.3(1)% which together with single-qubit operations forms a universal set
of quantum gates. The gate operation is performed on a pair of qubits encoded
in two trapped calcium ions using a single amplitude-modulated laser beam
interacting with both ions at the same time. A robust gate operation, mapping
separable states onto maximally entangled states is achieved by adiabatically
switching the laser-ion coupling on and off. We analyse the performance of a
single gate and concatenations of up to 21 gate operations. The gate mechanism
holds great promise not only for two-qubit but also for multi-qubit operations.


title: Signatures for right-handed neutrinos at the Large Hadron Collider

abstract:
  We explore possible signatures for right-handed neutrinos in TeV scale B-L
extension of the Standard Model (SM) at the Large Hadron Collider (LHC). The
studied four lepton signal has a tiny SM background. We find the signal
experimentally accessible at LHC for the considered parameter regions.


title: Lie algebras of smooth sections

abstract:
  Lie algebras of smooth sections are Lie algebras obtained from bundles of Lie
algebras, where the latter are vector bundles of which the fibers are Lie
algebras. We also consider the $\operatorname{C}^k$-sections for $k \in
\mathbb{N}$. This paper studies the derivations, the centroid and the
isomorphisms of such Lie algebras and generalizes some facts from Pierre
Lecomte's publications in 1979 and 1980 to the case where the fiber is perfect
or centerfree and it gives some more explicit proofs.


title: The Subaru/XMM-Newton Deep Field - II. The 37 brightest radio sources

abstract:
  We study the 37 brightest radio sources in the Subaru/XMM-Newton Deep Field
(SXDF). We have spectroscopic redshifts for 24 of 37 objects and photometric
redshifts for the remainder, yielding a median redshift z_med for the whole
sample of z_med ~= 1.1 and a median radio luminosity close to the `FRI/FRII'
luminosity divide. Using mid-IR (Spitzer MIPS 24 um) data we expect to trace
nuclear accretion activity, even if it is obscured at optical wavelengths,
unless the obscuring column is extreme. Our results suggest that above the
FRI/FRII radio luminosity break most of the radio sources are associated with
objects that have excess mid-IR emission, only some of which are broad-line
objects, although there is one clear low-accretion-rate object with an FRI
radio structure. For extended steep-spectrum radio sources, the fraction of
objects with mid-IR excess drops dramatically below the FRI/FRII luminosity
break, although there exists at least one high-accretion-rate `radio-quiet'
QSO. We have therefore shown that the strong link between radio luminosity (or
radio structure) and accretion properties, well known at z ~ 0.1, persists to z
~ 1. Investigation of mid-IR and blue excesses shows that they are correlated
as predicted by a model in which, when significant accretion exists, a torus of
dust absorbs ~30% of the light, and the dust above and below the torus scatters
>~1% of the light.


title:
Measurement of the baryonic acoustic oscillation scale in 21 cm
  intensity fluctuations during the reionisation era

abstract:
  It has recently been suggested that the power spectrum of redshifted 21cm
fluctuations could be used to measure the scale of baryonic acoustic
oscillations (BAOs) during the reionisation era. The resulting measurements are
potentially as precise as those offered by the next generation of galaxy
redshift surveys at lower redshift. However unlike galaxy redshift surveys,
which in the linear regime are subject to a scale independent galaxy bias, the
growth of ionised regions during reionisation is thought to introduce a
strongly scale dependent relationship between the 21cm and mass power spectra.
We use a semi-numerical model for reionisation to assess the impact of ionised
regions on the precision and accuracy with which the BAO scale could be
measured using redshifted 21cm observations. For a model in which reionisation
is completed at z~6, we find that the constraints on the BAO scale are not
systematically biased at z > 6.5. In this scenario, and assuming the
sensitivity attainable with a low-frequency array comprising 10 times the
collecting area of the Murchison Widefield Array, the BAO scale could be
measured to within 1.5 per cent in the range 6.5 < z < 7.5.


title:
An Identity of Andrews and a New Method for the Riordan Array Proof of
  Combinatorial Identities

abstract:
  We consider an identity relating Fibonacci numbers to Pascal's triangle
discovered by G. E. Andrews. Several authors provided proofs of this identity,
most of them rather involved or else relying on sophisticated number
theoretical arguments. We present a new proof, quite simple and based on a
Riordan array argument. The main point of the proof is the construction of a
new Riordan array from a given Riordan array, by the elimination of elements.
We extend the method and as an application we obtain other identities, some of
which are new. An important feature of our construction is that it establishes
a nice connection between the generating function of the $A-$sequence of a
certain class of Riordan arrays and hypergeometric functions.


title:
Note on the equivalence of the label propagation method of community
  detection and a Potts model approach

abstract:
  We show that the recently introduced label propagation method for detecting
communities in complex networks is equivalent to find the local minima of a
simple Potts model. Applying to empirical data, the number of such local minima
was found to be very high, much larger than the number of nodes in the graph.
The aggregation method for combining information from more local minima shows a
tendency to fragment the communities into very small pieces.


title:
Impact of misfit strain on the properties of tetragonal Pb(Zr,Ti)O3 thin
  film heterostructures

abstract:
  Heterostructures consisting of PbZr0.2Ti0.8O3 and PbZr0.4Ti0.6O3 films grown
on a SrTiO3 (100) substrate with a SrRuO3 bottom electrode were prepared by
pulsed laser deposition. Using the additional interface provided by the
ferroelectric bilayer structure and changing the sequence of the layers, the
dislocation content and domain patterns were varied. The resulting
microstructure was investigated by transmission electron microscopy.
Macroscopic ferroelectric measurements have shown a large impact of the
formation of dislocations and the a/c domain structure on the ferroelectric
polarization and dielectric constant. A thermodynamic analysis using the
LANDAU-GINZBURG-DEVONSHIRE approach that takes into account the ratio of the
thicknesses of the two ferroelectric layers and electrostatic coupling is used
to describe the experimental data.


title: Nanoribbons in external electric fields

abstract:
  We consider the Schr\"odinger operator on nanoribbons (tight-binding models)
in an external electric potentials $V$. The corresponding electric field is
perpendicular to the axis of the nanoribbon. If V=0, then the spectrum of the
Schr\"odinger operator consists of two spectral bands and the flat band (i.e.,
the eigenvalue with infinite multiplicity) between them. If we switch on an
weak electric potential $V\to 0$, then we determine the asymptotics of the
spectral bands for small fields. In particular, we describe all potentials when
the unperturbed eigenvalue remains the flat band and when one becomes the small
band of the continuous spectrum.


title: On Matter Coupling in 5D Kaluza-Klein Model

abstract:
  We analyze some unphysical features of the geodesic approach to matter
coupling in a compactified Kaluza-Klein scenario, like the q/m puzzle and the
huge massive modes. We propose a new approach, based on Papapetrou multipole
expansion, that provides a new equation for the motion of a test particle. We
show how this equation provides right couplings and does not generate huge
massive modes.


title: Statistics of work performed on a forced quantum oscillator

abstract:
  Various aspects of the statistics of work performed by an external classical
force on a quantum mechanical system are elucidated for a driven harmonic
oscillator. In this special case two parameters are introduced that are
sufficient to completely characterize the force protocol. Explicit results for
the characteristic function of work and the respective probability distribution
are provided and discussed for three different types of initial states of the
oscillator: microcanonical, canonical and coherent states. Depending on the
choice of the initial state the probability distributions of the performed work
may grossly differ. This result in particular holds also true for identical
force protocols. General fluctuation and work theorems holding for
microcanonical and canonical initial states are confirmed.


title: On some congruence properties of elliptic curves

abstract:
  In this paper, as a result of a theorem of Serre on congruence properties, a
complete solution is given for an open question (see the text) presented
recently by Kim, Koo and Park. Some further questions and results on similar
types of congruence properties of elliptic curves are also presented and
discussed.


title:
Paradan's wall crossing formula for partition functions and
  Khovanski-Pukhlikov differential operator

abstract:
  We give an elementary algebraic proof of Paradan's wall crossing formulae for
partition functions. We also express such jumps in volume and partition
functions by one dimensional residue formulae. Subsequently we reprove the
relation between them as given by the application of a generalized
Khovanskii-Pukhlikov differential operator.


title: Transmutation of momentum into position in magnetic vortices

abstract:
  We show that transmutation of linear momentum into position may occur in a
system of three magnetic vortices thanks to a direct link between topology and
dynamics in a ferromagnet. This happens via exchange between the linear
momentum of a vortex-antivortex pair and the position of a single vortex during
a semi-elastic scattering process. Vortex polarity switching occurs in the case
of inelastic collisions.


title:
Using Spatially Varying Pixels Exposures and Bayer-covered Photosensors
  for High Dynamic Range Imaging

abstract:
  The method of a linear high dynamic range imaging using solid-state
photosensors with Bayer colour filters array is provided in this paper. Using
information from neighbour pixels, it is possible to reconstruct linear images
with wide dynamic range from the oversaturated images. Bayer colour filters
array is considered as an array of neutral filters in a quasimonochromatic
light. If the camera's response function to the desirable light source is known
then one can calculate correction coefficients to reconstruct oversaturated
images. Reconstructed images are linearized in order to provide a linear high
dynamic range images for optical-digital imaging systems. The calibration
procedure for obtaining the camera's response function to the desired light
source is described. Experimental results of the reconstruction of the images
from the oversaturated images are presented for red, green, and blue
quasimonochromatic light sources. Quantitative analysis of the accuracy of the
reconstructed images is provided.


title:
Traffic Grooming in Unidirectional WDM Rings with Bounded Degree Request
  Graph

abstract:
  Traffic grooming is a major issue in optical networks. It refers to grouping
low rate signals into higher speed streams, in order to reduce the equipment
cost. In SONET WDM networks, this cost is mostly given by the number of
electronic terminations, namely ADMs. We consider the case when the topology is
a unidirectional ring. In graph-theoretical terms, the traffic grooming problem
in this case consists in partitioning the edges of a request graph into
subgraphs with a maximum number of edges, while minimizing the total number of
vertices of the decomposition. We consider the case when the request graph has
bounded maximum degree $\Delta$, and our aim is to design a network being able
to support any request graph satisfying the degree constraints. The existing
theoretical models in the literature are much more rigid, and do not allow such
adaptability. We formalize the problem, and solve the cases $\Delta=2$ (for all
values of $C$) and $\Delta = 3$ (except the case C=4). We also provide lower
and upper bounds for the general case.


title: Neutrinos, Axions and Conformal Symmetry

abstract:
  We demonstrate that radiative breaking of conformal symmetry (and
simultaneously electroweak symmetry) in the Standard Model with right-chiral
neutrinos and a minimally enlarged scalar sector induces spontaneous breaking
of lepton number symmetry, which naturally gives rise to an axion-like particle
with some unusual features. The couplings of this `axion' to Standard Model
particles, in particular photons and gluons, are entirely determined (and
computable) via the conformal anomaly, and their smallness turns out to be
directly related to the smallness of the masses of light neutrinos.


title:
Magnetic field-induced one-magnon Raman scattering in the magnon
  Bose-Einstein condensation phase of TlCuCl$_{3}$

abstract:
  We report the observation of the $A_{\rm g}$-symmetric one-magnon Raman peak
in the magnon Bose-Einstein condensation phase of TlCuCl$_{3}$. Its Raman shift
traces the one-magnon energy at the magnetic $\Gamma$ point, and its intensity
is proportional to the squared transverse magnetization. The appearance of the
one-magnon Raman scattering originates from the exchange magnon Raman process
and reflects the change of the magnetic-state symmetry. Using the bond-operator
representation, we theoretically clarify the Raman selection rules, being
consistent with the experimental results.


title: The infrared conductivity of graphene

abstract:
  We study the infrared conductivity of graphene at finite chemical potential
and temperature taking into account the effect of phonons and disorder due to
charged impurities and unitary scatterers. The screening of the long-range
Coulomb potential is treated using the random phase approximation coupled to
the coherent potential approximation. The effect of the electron-phonon
coupling is studied in second-order perturbation theory. The theory has
essentially one free parameter, namely, the number of charge impurities per
carbon, n^{{\rm C}}_i. We find an anomalous enhancement of the conductivity in
a frequency region that is blocked by Pauli exclusion and an impurity
broadening of the conductivity threshold. We also find that phonons induce
Stokes and anti-Stokes lines that produce an excess conductivity, when compared
to the far infrared value of \sigma_0 = (\pi/2) e^2/h.


title:
On the lack of strong O-line excess in the Coma cluster outskirts from
  Suzaku

abstract:
  About half of the baryons in the local Universe are thought to reside in the
so-called warm-hot intergalactic medium (WHIM) at temperatures of 0.1-10
million K. Thermal soft excess emission in the spectrum of some cluster
outskirts that contains OVII and/or OVIII emission lines is regarded as
evidence of the WHIM, although the origin of the lines is controversial due to
strong Galactic and solar system foreground emission. We observed the Coma-11
field, where the most prominent thermal soft excess has ever been reported,
with Suzaku XIS in order to make clear the origin of the excess. We did not
confirm OVII or OVIII excess emission. The OVII and OVIII intensity in Coma-11
is more than 5 sigma below that reported before and we obtained 2 sigma upper
limits of 2.8 and 2.9 photons cm^-2 s^-1 sr^-1 for OVII and OVIII,
respectively. The intensities are consistent with those in another field
(Coma-7) that we measured, and with other measurements in the Coma outskirts
(Coma-7 and X Com fields with XMM-Newton). We did not confirm the spatial
variation within Coma outskirts. The strong oxygen emission lines previously
reported are likely due to solar wind charge exchange.


title:
Influence of van der Waals forces on the adsorption structure of benzene
  on silicon

abstract:
  Two different adsorption configurations of benzene on the Si(001)-(2x1)
surface, the tight-bridge and butterfly structures, were studied using density
functional theory. Several exchange and correlation functionals were used,
including the recently developed vdW-DF functional, which accounts for the
effect of van der Waals forces. In contrast to the PBE, revPBE and other GGA
functionals, the vdW-DF functional finds that, for most coverages, the
adsorption energy of the butterfly structure is greater than that of the
tight-bridge structure.


title: On five-dimensional non-extremal charged black holes and FRW cosmology

abstract:
  We consider static non-extremal charged black hole solutions in the context
of N=2 gauged supergravity theories in five dimensions, and we show that they
satisfy first-order flow equations. Then we analyze the motion of the dual
brane in these black hole backgrounds. We express the entropy in terms of a
Cardy-Verlinde-type formula, and we show that the equations describing the FRW
cosmology on the brane have a form that is similar to the equations for the
entropy and for the Casimir energy on the brane. We also briefly comment on the
inclusion of a Gauss-Bonnet term in the analysis.


title: The VLT-FLAMES Survey of Massive Stars

abstract:
  The VLT-FLAMES Survey of Massive Stars was an ESO Large Programme to
understand rotational mixing and stellar mass-loss in different metallicity
environments, in order to better constrain massive star evolution. We gathered
high-quality spectra of over 800 stars in the Galaxy and in the Magellanic
Clouds. A sample of this size is unprecedented, enabled by the first
high-resolution, wide-field, multi-object spectrograph on an 8-m telescope. We
developed spectral analysis techniques that, in combination with non-LTE,
line-blanketed model atmospheres, were used to quantitatively characterise
every star. The large sample, combined with the theoretical developments, has
produced exciting new insights into the evolution of the most massive stars.


title: Mean-periodicity and zeta functions

abstract:
  This paper establishes new bridges between number theory and modern harmonic
analysis, namely between the class of complex functions, which contains zeta
functions of arithmetic schemes and closed with respect to product and
quotient, and the class of mean-periodic functions in several spaces of
functions on the real line. In particular, the meromorphic continuation and
functional equation of the zeta function of arithmetic scheme with its expected
analytic shape is shown to correspond to mean-periodicity of a certain
explicitly defined function associated to the zeta function. This
correspondence can be viewed as an extension of the Hecke--Weil correspondence.
The case of elliptic curves over number fields and their regular models is
treated in more details, and many other examples are included as well.


title: N=4 SYM on S^3 with Near Critical Chemical Potentials

abstract:
  We study the N = 4 theory at weak coupling, on a three sphere in the grand
canonical ensemble with R symmetry chemical potentials. We focus attention on
near critical values for the chemical potentials, above which the classical
theory has no ground state. By computing a one loop effective potential for the
light degrees of freedom in this regime, we show the existence of flat
directions of complex dimension N, 2N and 3N for one, two and three critical
chemical potentials respectively; these correspond to one half, one quarter and
one-eighth BPS states becoming light respectively at the critical values. At
small finite temperature we show that the chemical potentials can be continued
beyond their classical limiting values to yield a deconfined metastable phase
with lifetime diverging in the large N limit. Our low temperaure analysis
complements the high temperature metastability found by Yamada and Yaffe. The
resulting phase diagram at weak coupling bears a striking resemblance to the
strong coupling phase diagram for charged AdS black holes. Our analysis also
reveals subtle qualitative differences between the two regimes.


title: gamma-vibrational states in superheavy nuclei

abstract:
  Recent experimental advances have made it possible to study excited structure
in superheavy nuclei. The observed states have often been interpreted as
quasi-particle excitations. We show that in superheavy nuclei collective
vibrations systematically appear as low-energy excitation modes. By using the
microscopic Triaxial Projected Shell Model, we make a detailed prediction on
gamma-vibrational states and their E2 transition probabilities to the ground
state band in Fermium and Nobelium isotopes where active structure research is
going on, and in 270Ds, the heaviest isotope where decay data have been
obtained for the ground-state and for an isomeric state.


title:
Combined Intra- and Inter-domain Traffic Engineering using Hot-Potato
  Aware Link Weights Optimization

abstract:
  A well-known approach to intradomain traffic engineering consists in finding
the set of link weights that minimizes a network-wide objective function for a
given intradomain traffic matrix. This approach is inadequate because it
ignores a potential impact on interdomain routing. Indeed, the resulting set of
link weights may trigger BGP to change the BGP next hop for some destination
prefixes, to enforce hot-potato routing policies. In turn, this results in
changes in the intradomain traffic matrix that have not been anticipated by the
link weights optimizer, possibly leading to degraded network performance.
  We propose a BGP-aware link weights optimization method that takes these
effects into account, and even turns them into an advantage. This method uses
the interdomain traffic matrix and other available BGP data, to extend the
intradomain topology with external virtual nodes and links, on which all the
well-tuned heuristics of a classical link weights optimizer can be applied. A
key innovative asset of our method is its ability to also optimize the traffic
on the interdomain peering links. We show, using an operational network as a
case study, that our approach does so efficiently at almost no extra
computational cost.


title: Period changes in six semi-detached Algol-type binaries

abstract:
  Six semi-detached Algol-type binaries lacking a period analysis were chosen
to test for a presence of a third body. The O-C diagrams of these binaries were
analyzed with the least-squares method by using all available times of minima.
Also fourteen new minima, obtained from our observations, were included in the
present research. The light-time effect was adopted as a main factor for the
detailed description of the long-term period changes. Third bodies were found
with orbital periods from 46 up to 84 years, and eccentricities from 0.0 to
0.78 for the selected binaries. The mass functions and the minimal masses of
such bodies were also calculated.


title: Lattice Boltzmann simulations of soft matter systems

abstract:
  This article concerns numerical simulations of the dynamics of particles
immersed in a continuum solvent. As prototypical systems, we consider colloidal
dispersions of spherical particles and solutions of uncharged polymers. After a
brief explanation of the concept of hydrodynamic interactions, we give a
general overview over the various simulation methods that have been developed
to cope with the resulting computational problems. We then focus on the
approach we have developed, which couples a system of particles to a lattice
Boltzmann model representing the solvent degrees of freedom. The standard D3Q19
lattice Boltzmann model is derived and explained in depth, followed by a
detailed discussion of complementary methods for the coupling of solvent and
solute. Colloidal dispersions are best described in terms of extended particles
with appropriate boundary conditions at the surfaces, while particles with
internal degrees of freedom are easier to simulate as an arrangement of mass
points with frictional coupling to the solvent. In both cases, particular care
has been taken to simulate thermal fluctuations in a consistent way. The
usefulness of this methodology is illustrated by studies from our own research,
where the dynamics of colloidal and polymeric systems has been investigated in
both equilibrium and nonequilibrium situations.


title:
Impact of CSI on Distributed Space-Time Coding in Wireless Relay
  Networks

abstract:
  We consider a two-hop wireless network where a transmitter communicates with
a receiver via $M$ relays with an amplify-and-forward (AF) protocol. Recent
works have shown that sophisticated linear processing such as beamforming and
distributed space-time coding (DSTC) at relays enables to improve the AF
performance. However, the relative utility of these strategies depend on the
available channel state information at transmitter (CSIT), which in turn
depends on system parameters such as the speed of the underlying fading channel
and that of training and feedback procedures. Moreover, it is of practical
interest to have a single transmit scheme that handles different CSIT
scenarios. This motivates us to consider a unified approach based on DSTC that
potentially provides diversity gain with statistical CSIT and exploits some
additional side information if available. Under individual power constraints at
the relays, we optimize the amplifier power allocation such that pairwise error
probability conditioned on the available CSIT is minimized. Under perfect CSIT
we propose an on-off gradient algorithm that efficiently finds a set of relays
to switch on. Under partial and statistical CSIT, we propose a simple
waterfilling algorithm that yields a non-trivial solution between maximum power
allocation and a generalized STC that equalizes the averaged amplified noise
for all relays. Moreover, we derive closed-form solutions for M=2 and in
certain asymptotic regimes that enable an easy interpretation of the proposed
algorithms. It is found that an appropriate amplifier power allocation is
mandatory for DSTC to offer sufficient diversity and power gain in a general
network topology.


title: Quantum optics with bosons and fermions

abstract:
  Atom optics, a field which takes much inspiration from traditional optics,
has advanced to the point that some of the fundamental experiments of quantum
optics, involving photon correlations, have found atomic analogs. We discuss
some recent experiments on atom bunching and anti-bunching as well as some
prospects for extending them to the field of many body physics.


title: A gauge theory analog of some "stringy" D-instantons

abstract:
  We argue that one can see a specific class of "stringy" D-instantons in the
underlying 4D gauge theory as the UV completion of an ordinary gauge instanton
of a completely broken gauge group corresponding to the "empty" cycle the
D-instanton is located on. In this sense, the D-instanton induced
non-perturbative superpotential can be qualitatively inferred directly from
pure field-theory considerations.


title: On Monge-Kantorovich Problem in the Plane

abstract:
  We transfer the celebrating Monge-Kontorovich problem in a bounded domain of
Euclidean plane into a Dirichlet boundary problem associated to a quasi-linear
elliptic equation with $0-$order term missing in its diffusion coefficients:
\begin{eqnarray*} A(x, F'_x)F''_{xx}+B(y, F'_y)F''_{yy}&=&C(x, y, F'_x, F'_y)
\end{eqnarray*} where $A(.,.)>0, B(.,.)>0$ and $C$ are functions based on the
initial distributions, $F$ is an unknown probability distribution function and
therefore closed the former problem.


title: A Laboratory Study of the Reduction of Iron Oxides by Hydrogen

abstract:
  To reduce the emission of greenhouse gases by the steel industry,
particularly for ironmaking, the production of DRI (Direct Reduced Iron) using
hydrogen as the reducing gas instead of carbon monoxide is being considered. In
this context, the reduction of pure hematite by hydrogen was studied at the
laboratory scale, varying the experimental conditions and observing the rate
and the course of the reaction. All the reduction experiments were performed in
a thermobalance and supplementary characterization methods were used like
scanning and transmission electron microscopy, X-ray diffraction, and
M\"ossbauer spectrometry. The influence of rising temperature in the range
550-900 degrees C is to accelerate the reaction; no slowing down was observed,
contrary to some literature conclusions. A series of experiments consisted in
interrupting the runs before complete conversion, thus enabling the
characterization of partially reduced samples. Interpretation confirms the
occurrence of three successive and rather separate reduction steps, through
magnetite and wustite to iron, and illustrates a clear structural evolution of
the samples. Finally, the influence of the sample type was revealed comparing a
regular powder, a nanopowder and a sintered sample. The regular powder proved
to be the most reactive despite its larger grain size, due to a more porous
final structure.


title: Kondo physics in a dissipative environment

abstract:
  We report nonperturbative results for the interacting quantum-critical
behavior in a Bose-Fermi Kondo model describing a spin-1/2 coupled both to a
fermionic band with a pseudogap density of states and to a dissipative bosonic
bath. The model serves as a paradigm for studying the interplay between Kondo
physics and low-energy dissipative modes in strongly correlated systems.


title:
A kinetic equation for linear fractional stable motion with applications
  to space plasma physics

abstract:
  Levy flights and fractional Brownian motion (fBm) have become exemplars of
the heavy tailed jumps and long-ranged memory seen in space physics and
elsewhere. Natural time series frequently combine both effects, and Linear
Fractional Stable Motion (LFSM) is a model process of this type, combining
alpha-stable jumps with a memory kernel. In contrast complex physical
spatiotemporal diffusion processes where both the above effects compete-dubbed
"ambivalent" by Brockmann et al (2006}-have for many years been modelled using
the fully fractional (FF) kinetic equation for the continuous time random walk
(CTRW), with power laws in the pdfs of both jump size and waiting time. We
derive the analogous kinetic equation for LFSM and show that it has a diffusion
coefficient with a power law in time rather than having a fractional time
derivative like the CTRW. We develop earlier comments by Lutz (2001) on how fBm
differs from its fractional time process counterpart. We go on to argue more
physically why LFSM and the FFCTRW might indeed be expected to differ, and
discuss some preliminary results on the scaling of burst "sizes" and
"durations" in LFSM time series, with applications to modelling existing
observations in space physics.


title: A prime sensitive Hankel determinant of Jacobi symbol enumerators

abstract:
  We show that the determinant of a Hankel matrix of odd dimension n whose
entries are the enumerators of the Jacobi symbols which depend on the row and
the column indices vanishes iff n is composite. If the dimension is a prime p,
then the determinant evaluates to a polynomial of degree p-1 which is the
product of a power of p and the generating polynomial of the partial sums of
Legendre symbols. The sign of the determinant is determined by the quadratic
character of -1 modulo p. The proof of the evaluation makes use of elementary
properties of Legendre symbols, quadratic Gauss sums and orthogonality of
trigonometric functions.


title:
Charged Higgs Boson Effects in the Production and Decay of a Heavy
  Majorana Neutrino at the LHC

abstract:
  We consider a new interaction between a heavy Majorana neutrino (N) and a
charged Higgs boson (H+) and show that it can have drastic implications on
lepton number violating (LNV) signal of same-sign dileptons at the LHC. The LNV
signal of heavy Majorana neutrinos previously considered at the LHC, pp -> l+ N
-> l+ l+ W-, may be overwhelmed by pp -> l+ N -> l+ l+ H-. With the subsequent
decays H- -> b t(bar) or H- -> W- H^0, the heavy Majorana neutrino production
leads to the spectacular events of l+ l+ b b(bar) + 2 jets. We also explore the
case m_N < m_{H+}, where the decay H+ -> l+ N can become the dominant
N-production mechanism at the LHC. In particular, we show that the process g b
-> t H- followed by t -> b W+ and H- -> l- N -> l- l- W+ could lead to another
type of spectacular events of l- l- b + 4 jets.


title: Rational 6-cycles under iteration of quadratic polynomials

abstract:
  We present a proof, which is conditional on the Birch and Swinnerton-Dyer
Conjecture for a specific abelian variety, that there do not exist rational
numbers x and c such that x has exact period N = 6 under the iteration x |->
x^2 + c. This extends earlier results by Morton for N = 4 and by Flynn, Poonen
and Schaefer for N = 5.


title:
Using Sohn's law of additive reaction times for modeling a multiparticle
  reactor. The case of the moving bed furnace converting uranium trioxide into
  tetrafluoride

abstract:
  One of the major issues with multiparticle reactors is to handle their
multiscale aspect. For modeling, it usually comes to coupling a reactor model
(describing the phenomena at the macroscopic scale) with a so-called grain
model (simulating the behavior of a single grain or a particle). An interesting
approach proposed by H.Y. Sohn (1978) is to use the law of additive reaction
times in order to calculate, approximately but analytically, the reaction rate
of a particle in the reactor model. Its great advantage, compared to a
numerical grain model, is to drastically reduce the computation time,
particularly in the case of complex reactor models. This is the approach we
retained for modeling the moving bed furnace, a counter-current gas-solid
reactor used in the nuclear fuel-making route for producing uranium
tetrafluoride from uranium trioxide. The numerical model we developed is
2-dimensional, steady-state and based on the finite volume method. It describes
solid and gas flow, convective, conductive and radiative heat transfers, and
six chemical reactions involved in the process. The law of additive reaction
times is used to calculate analytically the rate of the three principal
gas-solid reactions at every discrete point in the reactor. We have
demonstrated the validity of this approach by comparing its results with those
calculated from a numerical grain model. Also detailed in the paper are the
main results of the moving bed furnace model itself and the possibilities of
optimizing the process revealed by the calculations.


title: A study of B->X(3872) K, with X(3872)->J/Psi pi+ pi-

abstract:
  We present measurements of the decays B+ -> X(3872) K+ and B0 -> X(3872) K0
with X(3872) -> Jpsi pi+ pi-. The data sample used, collected with the BABAR
detector at the PEP-II e+e- asymmetric-energy storage ring, corresponds to 455
x 10^6 BBbar pairs. Branching fraction measurements of BF(B+ -> X(3872) K+) x
BF(X(3872) -> Jpsi pi+ pi-) = (8.4 +/- 1.5 +/- 0.7) x 10^{-6} and BF(B0 ->
X(3872) K0) x BF(X(3872) -> Jpsi pi+ pi- = (3.5 +/- 1.9 +/- 0.4) x 10^{-6} are
obtained. We set an upper limit on the natural width of the X(3872) of Gamma <
3.3 MeV/c^2 at the 90% confidence level.


title:
Aggregation by exponential weighting, sharp PAC-Bayesian bounds and
  sparsity

abstract:
  We study the problem of aggregation under the squared loss in the model of
regression with deterministic design. We obtain sharp PAC-Bayesian risk bounds
for aggregates defined via exponential weights, under general assumptions on
the distribution of errors and on the functions to aggregate. We then apply
these results to derive sparsity oracle inequalities.


title:
IPHAS discoveries of young stars towards Cyg OB2 and its southern
  periphery

abstract:
  We report on the discovery of over 50 strong Halpha emitting objects towards
the large OB association Cyg OB2 and the HII region DR 15 on its southern
periphery. This was achieved using the INT Photometric Halpha Survey of the
Northern Galactic Plane (IPHAS), combined with follow-up spectroscopy using the
MMT multi-object spectrometer HectoSpec. We present optical spectra,
supplemented with optical r', i' and Halpha photometry from IPHAS, and
near-infrared J, H, and K photometry from 2MASS. The position of the objects in
the (J - H) versus (H - K) diagram strongly suggests most of them are young.
Many show CaII IR triplet emission indicating that they are in a pre-main
sequence phase of evolution of T Tauri and Herbig Ae nature. Among these, we
have uncovered pronounced clustering of T Tauri stars roughly a degree south of
the centre of Cyg OB2, in an arc close to the HII region DR 15, and the radio
ring nebula G79.29+0.46, for which we discuss its candidacy as a luminous blue
variable (LBV). The emission line objects toward Cyg OB2 itself could be the
brightest most prominent component of a population of lower mass pre-main
sequence stars that has yet to be uncovered. Finally, we discuss the nature of
the ongoing star formation in Cyg OB2 and the possibility that the central OB
stars have triggered star formation in the periphery.


title: Auslander-Reiten theory revisited

abstract:
  We recall several results in Auslander-Reiten theory for finite-dimensional
algebras over fields and orders over complete local rings. Then we introduce
$n$-cluster tilting subcategories and higher theory of almost split sequences
and Auslander algebras there. Several examples are explained.


title:
Admission Control to Minimize Rejections and Online Set Cover with
  Repetitions

abstract:
  We study the admission control problem in general networks. Communication
requests arrive over time, and the online algorithm accepts or rejects each
request while maintaining the capacity limitations of the network. The
admission control problem has been usually analyzed as a benefit problem, where
the goal is to devise an online algorithm that accepts the maximum number of
requests possible. The problem with this objective function is that even
algorithms with optimal competitive ratios may reject almost all of the
requests, when it would have been possible to reject only a few. This could be
inappropriate for settings in which rejections are intended to be rare events.
  In this paper, we consider preemptive online algorithms whose goal is to
minimize the number of rejected requests. Each request arrives together with
the path it should be routed on. We show an $O(\log^2 (mc))$-competitive
randomized algorithm for the weighted case, where $m$ is the number of edges in
the graph and $c$ is the maximum edge capacity. For the unweighted case, we
give an $O(\log m \log c)$-competitive randomized algorithm. This settles an
open question of Blum, Kalai and Kleinberg raised in \cite{BlKaKl01}. We note
that allowing preemption and handling requests with given paths are essential
for avoiding trivial lower bounds.


title: Dynamics in shear flow studied by X-ray Photon Correlation Spectroscopy

abstract:
  X-ray photon correlation spectroscopy was used to measure the diffusive
dynamics of colloidal particles in a shear flow. The results presented here
show how the intensity autocorrelation functions measure both the diffusive
dynamics of the particles and their flow-induced, convective motion. However,
in the limit of low flow/shear rates, it is possible to obtain the diffusive
component of the dynamics, which makes the method suitable for the study of the
dynamical properties of a large class of complex soft-matter and biological
fluids. An important benefit of this experimental strategy over more
traditional X-ray methods is the minimization of X-ray induced beam damage.
While the method can be applied also for photon correlation spectroscopy in the
visible domain, our analysis shows that the experimental conditions under which
it is possible to measure the diffusive dynamics are easier to achieve at
higher q values (with X-rays).


title: Exploring a SNR/Molecular Cloud Association Within HESS J1745-303

abstract:
  HESS J1745-303 is an extended, unidentified VHE (very high energy) gamma-ray
source discovered using HESS in the Galactic Plane Survey. Since no obvious
counterpart has previously been found in longer-wavelength data, the processes
that power the VHE emission are not well understood. Combining the latest VHE
data with recent XMM-Newton observations and a variety of source catalogs and
lower-energy survey data, we attempt to match (from an energetic and positional
standpoint) the various parts of the emission of HESS J1745-303 with possible
candidates. Though no single counterpart is found to fully explain the VHE
emission, we postulate that at least a fraction of the VHE source may be
explained by a supernova-remnant/molecular-cloud association and/or a
high-spin-down-flux pulsar.


title: Dragging a polymer chain into a nanotube and subsequent release

abstract:
  We present a scaling theory and Monte Carlo (MC) simulation results for a
flexible polymer chain slowly dragged by one end into a nanotube. We also
describe the situation when the completely confined chain is released and
gradually leaves the tube. MC simulations were performed for a self-avoiding
lattice model with a biased chain growth algorithm, the pruned-enriched
Rosenbluth method. The nanotube is a long channel opened at one end and its
diameter $D$ is much smaller than the size of the polymer coil in solution. We
analyze the following characteristics as functions of the chain end position
$x$ inside the tube: the free energy of confinement, the average end-to-end
distance, the average number of imprisoned monomers, and the average stretching
of the confined part of the chain for various values of $D$ and for the number
of monomers in the chain, $N$. We show that when the chain end is dragged by a
certain critical distance $x^*$ into the tube, the polymer undergoes a
first-order phase transition whereby the remaining free tail is abruptly sucked
into the tube. This is accompanied by jumps in the average size, the number of
imprisoned segments, and in the average stretching parameter. The critical
distance scales as $x^*\sim ND^{1-1/\nu}$. The transition takes place when
approximately 3/4 of the chain units are dragged into the tube. The theory
presented is based on constructing the Landau free energy as a function of an
order parameter that provides a complete description of equilibrium and
metastable states. We argue that if the trapped chain is released with all
monomers allowed to fluctuate, the reverse process in which the chain leaves
the confinement occurs smoothly without any jumps. Finally, we apply the theory
to estimate the lifetime of confined DNA in metastable states in nanotubes.


title:
Susceptibilities and fluctuations in a Quark-Hadron System with
  Dynamical Recombination

abstract:
  Within the framework of the dynamical recombination approach implemented in
the partonic/hadronic quark Molecular Dynamics (qMD) model, we investigate
numerous QGP signals constructed from the correlations and fluctuations of
conserved charges, namely charged particle ratio fluctuations, charge transfer
fluctuations as well as various ratios of susceptibilities. We argue that more
generally, the covariances and the variances of the conserved charges divided
by the number of charged particles are a measure of the quark number
susceptibilities and are thus sensitive to the phase of the system.
Computations carried within samples of central qMD events from low AGS energies
on ($E_{lab}=2$ AGeV) up to the highest RHIC energies available
($\sqrt{s_{NN}}=200$ GeV) show that the final state calculations are always
compatible with the hadronic result. From analyses performed as a function of
time with our sample of events at $\sqrt{s_{NN}}=200$ GeV, we find the
recombination-like hadronization process the qMD system undergoes to be
responsible for the vanishing of the early stage QGP correlations and
fluctuations. These results might explain the compatibility of the measurements
on charged particle ratio fluctuations with the hadronic expectations and leave
no room for the experimental observation of any QGP fluctuation/correlation
signals based upon the susceptibilities of the conserved charges.


title:
Pion-to-photon transition distribution amplitudes in the non-local
  chiral quark model

abstract:
  We apply the non-local chiral quark model to study vector and axial
pion-to-photon transition amplitudes that are needed as a nonperturbative input
to estimate the cross section of pion annihilation into the real and virtual
photon. We use a simple form of the non-locality that allows to perform all
calculations in the Minkowski space and guaranties polynomiality of the TDA's.
We note only residual dependence on the precise form of the cut-off function,
however vector TDA that is symmetric in skewedness parameter in the local quark
model is no longer symmetric in the non-local case. We calculate also the
transition form-factors and compare them with existing experimental
parametrizations.


title: Self-repelling random walk with directed edges on Z

abstract:
  We consider a variant of self-repelling random walk on the integer lattice Z
where the self-repellence is defined in terms of the local time on oriented
edges. The long-time asymptotic scaling of this walk is surprisingly different
from the asymptotics of the similar process with self-repellence defined in
terms of local time on unoriented edges. We prove limit theorems for the local
time process and for the position of the random walker. The main ingredient is
a Ray-Knight-type of approach. At the end of the paper, we also present some
computer simulations which show the strange scaling behaviour of the walk
considered.


title: Galileo In-Situ Dust Measurements in Jupiter's Gossamer Rings

abstract:
  During its late orbital mission at Jupiter the Galileo spacecraft made two
passages through the giant planet's gossamer ring system. The impact-ionization
dust detector on board successfully recorded dust impacts during both ring
passages and provided the first in-situ measurements from a dusty planetary
ring. In all, a few thousand dust impacts were counted with the instrument
accumulators during both ring passages, but only a total of 110 complete data
sets of dust impacts were transmitted to Earth. Detected particle sizes range
from about 0.2 to 5 micron, extending the known size distribution by an order
of magnitude towards smaller particles than previously derived from optical
imaging (Showalter et al. 2008). The grain size distribution increases towards
smaller particles and shows an excess of these tiny motes in the Amalthea
gossamer ring compared to the Thebe ring. The size distribution for the
Amalthea ring derived from our in-situ measurements for the small grains agrees
very well with the one obtained from images for large grains. Our analysis
shows that particles contributing most to the optical cross-section are about 5
micron in radius, in agreement with imaging results. The measurements indicate
a large drop in particle flux immediately interior to Thebe's orbit and some
detected particles seem to be on highly-tilted orbits with inclinations up to
20 deg.


title:
Rigorous sufficient conditions for index-guided mode in microstructured
  dielectric waveguides

abstract:
  We derive a sufficient condition for the existence of index-guided modes in a
very general class of dielectric waveguides, including photonic-crystal fibers
(arbitrary periodic claddings, such as ``holey fibers''), anisotropic
materials, and waveguides with periodicity along the propagation direction.
This condition provides a rigorous guarantee of cutoff-free index-guided modes
in any such structure where the core is formed by increasing the index of
refraction (e.g. removing a hole). It also provides a weaker guarantee of
guidance in cases where the refractive index is increased ``on average''
(precisely defined). The proof is based on a simple variational method,
inspired by analogous proofs of localization for two-dimensional attractive
potentials in quantum mechanics.


title: Rise and fall of hidden string order of lattice bosons

abstract:
  We investigate the ground state properties of a newly discovered phase of one
dimensional lattice bosons with extended interactions (see E. G. Dalla Torre et
al., Phys. Rev. Lett. \textbf{97}, 260401 (2006)). The new phase, termed the
Haldane Insulator (HI) in analogy with the gapped phase of spin-1 chains, is
characterized by a non local order parameter, which can only be written as an
infinite string in terms of the bosonic densities. We show that the string
order can nevertheless be probed with physical fields that couple locally, via
the effect those fields have on the quantum phase transitions separating the
exotic phase from the conventional Mott and density wave phases. Using a field
theoretical analysis we show that a perturbation which breaks lattice inversion
symmetry gaps the critical point separating the Mott and Haldane phases and
eliminates the sharp distinction between them. This is remarkable given that
neither of these phases involves broken inversion symmetry. We also investigate
the evolution of the phase diagram with the tunable coupling between parallel
chains in an optical lattice setup. We find that inter-chain tunneling destroys
the direct phase transition between the Mott and Haldane insulators by
establishing an intermediate superfluid phase. On the other hand coupling the
chains only by weak repulsive interactions does not modify the structure of the
phase diagram. The theoretical predictions are confirmed with numerical
calculations using the Density Matrix Renormalization Group (DMRG).


title:
Tunneling study of cavity grade Nb: possible magnetic scattering at the
  surface

abstract:
  Tunneling spectroscopy was performed on Nb pieces prepared by the same
processes used to etch and clean superconducting radio frequency (SRF)
cavities. Air exposed, electropolished Nb exhibited a surface superconducting
gap delta=1.55 meV, characteristic of clean, bulk Nb. However the tunneling
density of states (DOS) was broadened significantly. The Nb pieces treated with
the same mild baking used to improve the Q-slope in SRF cavities, reveal a
sharper DOS. Good fits to the DOS were obtained using Shiba theory, suggesting
that magnetic scattering of quasiparticles is the origin of the gapless surface
superconductivity and a heretofore unrecognized contributor to the Q-slope
problem of Nb SRF cavities.


title: Note on constancy of some formal meromorphic maps

abstract:
  Segre sets are superfluous to verify that quotients of formal holomorphic
maps that are real on a minimal generic submanifold of positive CR dimension
must necessarily be constant.


title: Searching for Communities in Bipartite Networks

abstract:
  Bipartite networks are a useful tool for representing and investigating
interaction networks. We consider methods for identifying communities in
bipartite networks. Intuitive notions of network community groups are made
explicit using Newman's modularity measure. A specialized version of the
modularity, adapted to be appropriate for bipartite networks, is presented; a
corresponding algorithm is described for identifying community groups through
maximizing this measure. The algorithm is applied to networks derived from the
EU Framework Programs on Research and Technological Development. Community
groups identified are compared using information-theoretic methods.


title: Gravitons scattering from classical matter

abstract:
  The low energy scattering of gravitons from a composite extended system,
which is made of classical massive bodies, is considered; by using the Feynman
rules of effective quantum gravity, the corresponding cross-section is computed
to lowest order in powers of the gravitational coupling constant. For the
gravitons scattering from a rotating planet or a star, it is shown that the
classical limit of the matter-gravitons coupling in the effective quantum
gravity lagrangian leads to a low energy scattering amplitude which coincides
with the expression obtained in classical general relativity.


title:
Figuring out Actors in Text Streams: Using Collocations to establish
  Incremental Mind-maps

abstract:
  The recognition, involvement, and description of main actors influences the
story line of the whole text. This is of higher importance as the text per se
represents a flow of words and expressions that once it is read it is lost. In
this respect, the understanding of a text and moreover on how the actor exactly
behaves is not only a major concern: as human beings try to store a given input
on short-term memory while associating diverse aspects and actors with
incidents, the following approach represents a virtual architecture, where
collocations are concerned and taken as the associative completion of the
actors' acting. Once that collocations are discovered, they become managed in
separated memory blocks broken down by the actors. As for human beings, the
memory blocks refer to associative mind-maps. We then present several priority
functions to represent the actual temporal situation inside a mind-map to
enable the user to reconstruct the recent events from the discovered temporal
results.


title:
Magnetic phases of one-dimensional lattices with 2 to 4 fermions per
  site

abstract:
  We study the spectral and magnetic properties of one-dimensional lattices
filled with 2 to 4 fermions (with spin 1/2) per lattice site. We use a
generalized Hubbard model that takes account all interactions on a lattice
site, and solve the many-particle problem by exact diagonalization. We find an
intriguing magnetic phase diagram which includes ferromagnetism, spin-one
Heisenberg antiferromagnetism, and orbital antiferromagnetism.


title: Nuclear excitation by electron capture followed by fast x-ray emission

abstract:
  The resonance strength of the two-step process of nuclear excitation by
electron capture followed by $\gamma$ decay of the nucleus can be significantly
increased in highly charged ions if the resonant capture proceeds via an
excited electronic state with subsequent fast x-ray emission. For fully ionized
$^{238}_{92}\mathrm{U}$ and $^{232}_{90}\mathrm{Th}$, the {x-ray} decay
stabilizes the system against internal conversion of the captured electron,
with an increase of both nuclear lifetimes and resonance strengths of up to two
orders of magnitude compared with the case when occupied atomic orbitals
prevent the x-ray de-excitation. Applications of this effect to the measurement
of the not yet experimentally observed nuclear excitation by electron capture
and to dense astrophysical plasmas are discussed.


title:
Statistical complexity, Fisher-Shannon information, and Bohr orbits in
  the H-atom

abstract:
  The Fisher-Shannon information and a statistical measure of complexity are
calculated in the position and momentum spaces for the wave functions of the
H-atom. For each level of energy, it is found that these two indicators take
their minimum values on the orbitals that correspond to the classical
(circular) orbits in the Bohr atomic model, just those with the highest orbital
angular momentum.


title: A model of HIV budding and self-assembly, role of cell membrane

abstract:
  Budding from the plasma membrane of the host cell is an indispensable step in
the life cycle of the Human Immunodeficiency Virus (HIV), which belongs to a
large family of enveloped RNA viruses, retroviruses. Unlike regular enveloped
viruses, retrovirus budding happens {\em concurrently} with the self-assembly
of retrovirus protein subunits (Gags) into spherical virus capsids on the cell
membrane. Led by this unique budding and assembly mechanism, we study the free
energy profile of retrovirus budding, taking into account of the Gag-Gag
attraction energy and the membrane elastic energy. We find that if the Gag-Gag
attraction is strong, budding always proceeds to completion. During early stage
of budding, the zenith angle of partial budded capsids, $\alpha$, increases
with time as $\alpha \propto t^{1/3}$. However, when Gag-Gag attraction is
weak, a metastable state of partial budding appears. The zenith angle of these
partially spherical capsids is given by
$\alpha_0\simeq(\tau^2/\kappa\sigma)^{1/4}$ in a linear approximation, where
$\kappa$ and $\sigma$ are the bending modulus and the surface tension of the
membrane, and $\tau$ is a line tension of the capsid proportional to the
strength of Gag-Gag attraction. Numerically, we find $\alpha_0<0.3\pi$ without
any approximations. Using experimental parameters, we show that HIV budding and
assembly always proceed to completion in normal biological conditions. On the
other hand, by changing Gag-Gag interaction strength or membrane rigidity, it
is relatively easy to tune it back and forth between complete budding and
partial budding. Our model agrees reasonably well with experiments observing
partial budding of retroviruses including HIV.