title: Etale and motivic cohomology and ultraproducts of schemes

abstract:
  This paper is a continuation of the authors article "Enlargements of schemes"
(Log. Anal.1 (2007), no. 1, 1-60) We mainly study the behaviour of etale
cohomology, algebraic cycles and motives under ultraproducts respectively
enlargements. The main motivation for that is to find methods to transfer
statements about etale cohomology and algebraic cycles from characteristic zero
to positive characteristic and vice versa. We give one application to the
independence of $l$ of Betti numbers in etale cohomology and applications to
the complexity of algebraic cycles.


title:
Two-Loop Electroweak Corrections to the A^0 gamma gamma and A^0 g g
  Couplings of the CP-Odd Higgs Boson

abstract:
  Using the asymptotic-expansion technique, we compute the dominant two-loop
electroweak corrections, of O(G_F m_t^2), to production and decay via a pair of
photons or gluons of the CP-odd Higgs boson A^0 in a two-Higgs-doublet model
with low- to intermediate values of the Higgs-boson masses and ratio
tan(beta)=v_2/v_1 of the vacuum expectation values. We also study the influence
of a sequential heavy-fermion generation. The appearance of three gamma_5
matrices in closed fermion loops requires special care in the dimensional
regularisation of ultraviolet divergences. The finite renormalisation constant
for the pseudoscalar current effectively restoring the anticommutativity of the
gamma_5 matrix, familiar from perturbative quantum chromodynamics, is found not
to receive a correction in this order. We also revisit the dominant two-loop
electroweak correction to the H -> gamma gamma decay width in the standard
model with a fourth fermion generation.


title: Diagonalisation schemes and applications

abstract:
  These notes develop aspects of perturbation theory of matrices related to
so-called diagonalisation schemes. Primary focus is on constructive tools to
derive asymptotic expansions for small/large parameters of eigenvalues and
eigenprojections of families of matrices depending upon real/complex
parameters.
  Applications of the schemes in different frameworks --including hyperbolic
polynomials, asymptotic integration of ordinary differential equations,
diagonalisation within symbolic hierarchies and pseudo-differential decoupling
of hyperbolic-parabolic coupled systems-- are also discussed and references to
further applications given.


title: Electronic Structure of New LiFeAs High-Tc Superconductor

abstract:
  We present results of it ab initio LDA calculations of electronic structure
of "next generation" layered ironpnictide High-Tc superconductor LiFeAs
(Tc=18K). Obtained electronic structure of LiFeAs is very similar to recently
studied ReOFeAs (Re=La,Ce,Pr,Nd,Sm) and AFe2As2 (A=Ba,Sr) compounds. Namely
close to the Fermi level its electronic properties are also determined ma inly
by Fe 3d-orbitals of FeAs4 two-dimensional layers. Band dispersions of LiFeAs
are very similar to the LaOFeAs and BaFe2As2 systems as well as the shape of
the Fe-3d density o f states and Fermi surface.


title:
An Analysis of States in the Phase Space: From Quantum Mechanics to
  General Relativity

abstract:
  The paper has heuristic character. The conceptual frame, based on the
assumption of quantum uncertainty only, has been formerly introduced in two
papers [S. Tosto, Il Nuovo Cimento B, vol. 111, n.2, 1996 and S. Tosto, Il
Nuovo Cimento D, vol. 18, n.12, 1996]. Instead of attempting to increase the
accuracy of some existing computational model through a new kind of
approximation, these papers acknowledge since the beginning the lack of
deterministic information about the local properties of the constituent
particles, considered random, unknown and unpredictable and thus ignored in
principle. The leading idea is that the physical properties of quantum systems
could be inferred merely considering the delocalization ranges of dynamical
variables, rather than their local values. In effect, despite the agnostic
character of the approach proposed, both papers show that the kind of physical
information reachable reproduces exactly in all cases examined that obtained
solving the pertinent wave equations. The concept of quantum uncertainty is
further extended in the present paper to both space and time coordinates,
considering thus a unique spacetime delocalization range and still discarding
since the beginning the local values of the conjugate dynamical variables. The
paper shows an unexpected wealth of information obtainable simply extending the
concept of space uncertainty to that of spacetime uncertainty: the results are
inherently consistent with that of the operator formalism of wave mechanics and
with the basic postulates of special relativity, both inferred as corollaries.
Moreover, even the gravity appears to be essentially a quantum phenomenon. The
most relevant outcomes of special and general relativity are achieved as
straightforward consequence of the space-time delocalization of particles using
the simple quantum formalism first introduced in the early papers.


title: Cauchon diagrams for quantized enveloping algebras

abstract:
  Let $\mathfrak{g}$ be a finite dimensional complex simple Lie algebra,
$\mathbb{K}$ a commutative field and $q$ a nonzero element of $\mathbb{K}$
which is not a root of unity. To each reduced decomposition of the longest
element $w_0$ of the Weyl group $W$ corresponds a PBW basis of the quantised
enveloping algebra $\mathcal{U}_q^+(\mathfrak{g})$, and one can apply the
theory of deleting-derivation to this iterated Ore extension. In particular,
for each decomposition of $w_0$, this theory constructs a bijection between the
set of prime ideals in $\mathcal{U}_q^+(\mathfrak{g})$ that are invariant under
a natural torus action and certain combinatorial objects called Cauchon
diagrams. In this paper, we give an algorithmic description of these Cauchon
diagrams when the chosen reduced decomposition of $w_0$ corresponds to a good
ordering (in the sense of Lusztig \cite{Lu2}) of the set of positive roots.
This algorithmic description is based on the constraints that are coming from
Lusztig's admissible planes \cite{Lu2}: each admissible plane leads to a set of
constraints that a diagram has to satisfy to be Cauchon. Moreover, we
explicitely describe the set of Cauchon diagrams for explicit reduced
decomposition of $w_0$ in each possible type. In any case, we check that the
number of Cauchon diagrams is always equal to the cardinal of $W$. In
\cite{CM}, we use these results to prove that Cauchon diagrams correspond
canonically to the positive subexpressions of $w_0$. So the results of this
paper also give an algorithmic description of the positive subexpressions of
any reduced decomposition of $w_0$ corresponding to a good ordering.


title:
From differential equations to Boolean networks: A Case Study in
  modeling regulatory networks

abstract:
  Methods of modeling cellular regulatory networks as diverse as differential
equations and Boolean networks co-exist, however, without any closer
correspondence to each other. With the example system of the fission yeast cell
cycle control network, we here set the two approaches in relation to each
other. We find that the Boolean network can be formulated as a specific
coarse-grained limit of the more detailed differential network model for this
system. This lays the mathematical foundation on which Boolean networks can be
applied to biological regulatory networks in a controlled way.


title: The escape problem under stochastic volatility: the Heston model

abstract:
  We solve the escape problem for the Heston random diffusion model. We obtain
exact expressions for the survival probability (which ammounts to solving the
complete escape problem) as well as for the mean exit time. We also average the
volatility in order to work out the problem for the return alone regardless
volatility. We look over these results in terms of the dimensionless normal
level of volatility --a ratio of the three parameters that appear in the Heston
model-- and analyze their form in several assymptotic limits. Thus, for
instance, we show that the mean exit time grows quadratically with large spans
while for small spans the growth is systematically slower depending on the
value of the normal level. We compare our results with those of the Wiener
process and show that the assumption of stochastic volatility, in an apparent
paradoxical way, increases survival and prolongs the escape time.


title: Matrix random products with singular harmonic measure

abstract:
  Any Zariski dense countable subgroup of $SL(d,R)$ is shown to carry a
non-degenerate finitely supported symmetric random walk such that its harmonic
measure on the flag space is singular. The main ingredients of the proof are:
(1) a new upper estimate for the Hausdorff dimension of the projections of the
harmonic measure onto Grassmannians in $R^d$ in terms of the associated
differential entropies and differences between the Lyapunov exponents; (2) an
explicit construction of random walks with uniformly bounded entropy and
Lyapunov exponents going to infinity.


title: A General Framework for Sound and Complete Floyd-Hoare Logics

abstract:
  This paper presents an abstraction of Hoare logic to traced symmetric
monoidal categories, a very general framework for the theory of systems. Our
abstraction is based on a traced monoidal functor from an arbitrary traced
monoidal category into the category of pre-orders and monotone relations. We
give several examples of how our theory generalises usual Hoare logics (partial
correctness of while programs, partial correctness of pointer programs), and
provide some case studies on how it can be used to develop new Hoare logics
(run-time analysis of while programs and stream circuits).


title: String Free Energy, Hagedorn and Gauge/String Duality

abstract:
  We give examples of modeling the string free energy whose behavior mimics
that of QCD: a power-law at high temperature and an exponential decrease at low
temperature. Although the effective description is in terms of strings, no
limiting temperature exists, as expected for a crossover.


title: Spectral variability of GX 339-4 in a hard-to-soft state transition

abstract:
  We report on INTEGRAL observations of the bright black-hole transient GX
339-4 performed during the period August-September 2004. Our data cover three
different spectral states, namely Hard/Intermediate State, Soft/Intermediate
State and High/Soft State. We investigate the spectral variability of the
source across the different spectral states. The hard X-ray spectrum becomes
softer during the HIMS-to-SIMS transition, but it hardens when reaching the HSS
state. A principal component analysis demonstrates that most of the variability
occurs through two independent modes: a pivoting of the spectrum around 6 keV
(responsible for 75% of the variance) and an intensity variation of the hard
component (responsible for 21%). The pivoting is interpreted as due to changes
in the soft cooling photon flux entering the corona, the second mode as
fluctuations of the heating rate in the corona. Our spectral analysis of the
spectra of GX 339-4 shows a high energy excess with respect to pure thermal
Comptonisation models in the HIMS: a non-thermal power-law component seems to
be requested by data. In all spectral states joint IBIS, SPI and JEM-X data are
well represented by hybrid thermal/non-thermal Comptonisation (EQPAIR). The
spectral evolution seems to be predominantly driven by a reduction of the ratio
of the electron heating rate to the soft cooling photon flux in the corona,
l_h/l_s. The inferred accretion disc soft thermal emission increases by about
two orders of magnitude, while the Comptonised luminosity decreases by at most
a factor of 3. This confirms that the softening we observed is due to a major
increase in the flux of soft cooling photons in the corona associated with a
modest reduction of the electron heating rate.


title:
Heisenberg antiferromagnets with uniaxial exchange and cubic
  anisotropies in a field

abstract:
  Classical Heisenberg antiferromagnets with uniaxial exchange anisotropy and a
cubic anisotropy term in a field on simple cubic lattices are studied with the
help of ground state considerations and extensive Monte Carlo simulations.
Especially, we analyze the role of non-collinear structures of biconical type
occurring in addition to the well-known antiferromagnetic and spin-flop
structures. Pertinent phase diagrams are determined, and compared to previous
findings.


title: How the Scalar Field of Unified Dark Matter Models Can Cluster

abstract:
  We use scalar-field Lagrangians with a non-canonical kinetic term to obtain
unified dark matter models where both the dark matter and the dark energy, the
latter mimicking a cosmological constant, are described by the scalar field
itself. In this framework, we propose a technique to reconstruct models where
the effective speed of sound is small enough that the scalar field can cluster.
These models avoid the strong time evolution of the gravitational potential and
the large Integrated Sachs-Wolfe effect which have been a serious drawback of
previously considered models. Moreover, these unified dark matter scalar field
models can be easily generalized to behave as dark matter plus a dark energy
component behaving like any type of quintessence fluid.


title:
On Modelling a Relativistic Hierarchical (Fractal) Cosmology by Tolman's
  Spacetime. III. Numerical Results

abstract:
  This paper presents numerical solutions of particular Lemaitre-Tolman models
approximating a fractal behaviour along the past light cone, as discussed in
paper I (0807.0866) of this series. The initial conditions of the numerical
problem are discussed and the algorithm used to carry out the numerical
integrations is presented. It was found that the numerical solutions are stiff
across the flat-curved interface necessary to obtain the initial conditions of
the problem. The spatially homogeneous Friedmann models are treated as special
cases of the Lemaitre-Tolman solution and solved numerically. Extending the
results of paper II (0807.0869) on the Einstein-de Sitter model, to the $K =
\pm 1$ models, it was found that the open and closed Friedmann models also do
not appear to remain homogeneous along the backward null cone, with a vanishing
volume (average) density as one approaches the Big Bang singularity
hypersurface. Fractal solutions, that is, solutions representing an averaged
and smoothed-out single fractal, were obtained in all three classes of the
Lemaitre-Tolman metric, but only the hyperbolic ones were found to be in
agreement with observations, meaning that a possible Friedmann background
universe would have to be an open one. The best fractal metric obtained through
numerical simulations is also analysed in terms of evolution, homothetic
self-similarity, comparison with the respective spatially homogeneous case and
the fitting problem in cosmology. The paper finishes with a discussion on some
objections raised by some authors against a fractal cosmology.


title:
Single-particle and collective mode couplings associated with 1- and
  2-directional electronic ordering in metallic RTe$_3$ (R = Ho, Dy, Tb)

abstract:
  The coupling of phonons with collective modes and single-particle gap
excitations associated with one (1d) and two-directional (2d)
electronically-driven charge-density wave (CDW) ordering in metallic RTe_3 is
investigated as a function of rare-earth ion chemical pressure (R=Tb, Dy, Ho)
using femtosecond pump-probe spectroscopy. From the T-dependence of the CDW gap
\Delta_{CDW} and the amplitude mode (AM) we find that while the transition to a
1d-CDW ordered state at T_{c1} initially proceeds in an exemplary mean-field
(MF) -like fashion, below T_{c1}, \Delta_{CDW} is depressed and departs from
the MF behavior. The effect is apparently triggered by resonant mode-mixing of
the amplitude mode (AM) with a totally symmetric phonon at 1.75 THz. At low
temperatures, when the state evolves into a 2d-CDW ordered state at T_{c2} in
the DyTe_3 and HoTe_3, additional much weaker mode mixing is evident but no
soft mode is observed.


title: Finite dimensional representations of W-algebras

abstract:
  W-algebras of finite type are certain finitely generated associative algebras
closely related to the universal enveloping algebras of semisimple Lie
algebras. In this paper we prove a conjecture of Premet that gives an almost
complete classification of finite dimensional irreducible modules for
W-algebras. Also we study a relation between Harish-Chandra bimodules and
bimodules over $W$-algebras.


title: New Results from the Auger Observatory

abstract:
  The Auger project was designed to study the high-energy cosmic rays by
measuring the properties of the showers produced in the atmosphere. The
Southern Auger Observatory has taken data since January 2004 and is now
completed. Results on mass composition, energy spectrum and anisotropy of the
arrival directions are presented together with upper limits on the neutrino
fraction. The most important result is the recent observation of correlations
with nearby extragalactic objects.


title: Forward pi+/- production in p-O2 and p-N2 interactions at 12 GeV/c

abstract:
  Measurements of double-differential charged pion production cross-sections in
interactions of 12 GeV/c protons on O_2 and N_2 thin targets are presented in
the kinematic range 0.5 GeV/c < p_{\pi} < 8 GeV/c and 50 mrad < \theta_{\pi} <
250 mrad (in the laboratory frame) and are compared with p--C results. For
p--N_2 (p--O_2) interactions the analysis is performed using 38576 (7522)
reconstructed secondary pions. The analysis uses the beam instrumentation and
the forward spectrometer of the HARP experiment at CERN PS. The measured
cross-sections have a direct impact on the precise calculation of atmospheric
neutrino fluxes and on the improved reliability of extensive air shower
simulations by reducing the uncertainties of hadronic interaction models in the
low energy range. In particular, the present results allow the common
hypothesis that p--C data can be used to predict the p--N_2 and p--O_2 pion
production cross-sections to be tested.


title: Spin network coherent states for planar gravitational waves. I

abstract:
  This paper constructs coherent states for spin networks with planar symmetry.
After gauge-fixing, the full SU(2) symmetry is broken to U(1), but one cannot
simply use the U(1) limit of SU(2) coherent states, because the planar states
exhibit an unexpected O(3) symmetry arising from the closed loop character of
the transverse directions. The coherent states constructed in this paper obey
this symmetry. They are superpositions of holonomies which obey the residual
U(1) symmetry only on average; some holonomies in the superposition violate the
symmetry, although the U(1) quantum numbers of these holonomies are peaked at
values which obey the symmetry. Operators acting on coherent states give back a
c-number times the original state, plus small correction states, which make the
coherent state an approximate, rather than exact eigenstate of the operator. In
a follow-on paper, these small correction states are used to calculate small
corrections to the volume operator.


title: Lower bounds on dissipation upon coarse graining

abstract:
  By different coarse-graining procedures we derive lower bounds on the total
mean work dissipated in Brownian systems driven out of equilibrium. With
several analytically solvable examples we illustrate how, when, and where the
information on the dissipation is captured.


title:
Density matrix of the superposition of excitation on coherent states
  with thermal light and its statistical properties

abstract:
  A beam's density matrix that is described by the superposition of excitation
on coherent states with thermal noise (SECST) is presented, and its matrix
elements in Fock space are calculated. The maximum information transmitted by
the SECST beam is derived. It is more than that by coherent light beam and
increases as the excitation photon number increases. In addition, the
nonclassicality of density matrix is demonstrated by calculating its Wigner
function.


title:
Mode-locked oscillators in the positive and negative dispersion regimes:
  scenarios of destabilization

abstract:
  We analyze the influence of spectrally modulated dispersion and loss on the
stability of mode-locked oscillators. In the negative dispersion regime, a
soliton oscillator can be stabilized in a close proximity to zero-dispersion
wavelength, when spectral modulation of dispersion and loss are strong and
weak, respectively. If the dispersion is close to zero but positive, we observe
chaotic mode-locking or a stable coexistence of the pulse with the CW signal.
The results are confirmed by experiments with a Cr:YAG oscillator.


title: Gaussian Multiplicative Chaos revisited

abstract:
  In this article, we extend the theory of multiplicative chaos for positive
definite functions in Rd of the form f(x) = 2 ln+ T|x|+ g(x) where g is a
continuous and bounded function. The construction is simpler and more general
than the one defined by Kahane in 1985. As main application, we give a rigorous
mathematical meaning to the Kolmogorov-Obukhov model of energy dissipation in a
turbulent flow.


title:
The homotopy type of the space of symplectic balls in rational ruled
  4-manifolds

abstract:
  Let M:=(M^{4},\om) be a 4-dimensional rational ruled symplectic manifold and
denote by w_{M} its Gromov width. Let Emb_{\omega}(B^{4}(c),M) be the space of
symplectic embeddings of the standard ball B^4(c) \subset \R^4 of radius r and
of capacity c:= \pi r^2 into (M,\om). By the work of Lalonde and Pinsonnault,
we know that there exists a critical capacity \ccrit \in (0,w_{M}] such that,
for all c\in(0,\ccrit), the embedding space Emb_{\omega}(B^{4}(c),M) is
homotopy equivalent to the space of symplectic frames \SFr(M). We also know
that the homotopy type of Emb_{\omega}(B^{4}(c),M) changes when c reaches
\ccrit and that it remains constant for all c \in [\ccrit,w_{M}). In this
paper, we compute the rational homotopy type, the minimal model, and the
cohomology with rational coefficients of \Emb_{\omega}(B^{4}(c),M) in the
remaining case c \in [\ccrit,w_{M}). In particular, we show that it does not
have the homotopy type of a finite CW-complex.


title: The Word and Geodesic Problems in Free Solvable Groups

abstract:
  We study the computational complexity of the Word Problem (WP) in free
solvable groups $S_{r,d}$, where $r \geq 2$ is the rank and $d \geq 2$ is the
solvability class of the group. It is known that the Magnus embedding of
$S_{r,d}$ into matrices provides a polynomial time decision algorithm for WP in
a fixed group $S_{r,d}$. Unfortunately, the degree of the polynomial grows
together with $d$, so the uniform algorithm is not polynomial in $d$. In this
paper we show that WP has time complexity $O(r n \log_2 n)$ in $S_{r,2}$, and
$O(n^3 r d)$ in $S_{r,d}$ for $d \geq 3$. However, it turns out, that a
seemingly close problem of computing the geodesic length of elements in
$S_{r,2}$ is $NP$-complete. We prove also that one can compute Fox derivatives
of elements from $S_{r,d}$ in time $O(n^3 r d)$, in particular one can use
efficiently the Magnus embedding in computations with free solvable groups. Our
approach is based on such classical tools as the Magnus embedding and Fox
calculus, as well as, on a relatively new geometric ideas, in particular, we
establish a direct link between Fox derivatives and geometric flows on Cayley
graphs.


title:
Isovector energy-weighted sums for hot nuclei in presence of relaxation
  processes

abstract:
  We investigate the collective response function and the energy-weighted sums
m_k for isovector mode in hot nuclei. The approach is based on the collisional
kinetic theory and takes into consideration the temperature and the relaxation
effects. Taking into account a connection between the isovector sound mode and
the corresponding surface vibrations we have established the A-dependence of
the enhancement factor for the isovector sum rule in a good agreement with
experimental data. We have shown that the enhancement factor for the "model
independent" sum m_1 is only slightly sensitive to the temperature change.


title: Pairing in ultracold Fermi gases in the lowest Landau level

abstract:
  We study a rapidly rotating gas of unpolarized spin-1/2 ultracold fermions in
the two-dimensional regime when all atoms reside in the lowest Landau level.
Due to the presence of the spin degree of freedom both s-wave and p-wave
interactions are allowed at ultralow temperatures. We investigate the phase
diagram of this system as a function of the filling factor in the lowest Landau
level and in terms of the ratio between s- and p-wave interaction strengths. We
show that the presence of attractive interactions induces a wide regime of
phase separation with formation of maximally compact droplets that are either
fully polarized or composed of spin-singlets. In the regime with no phase
separation, we give evidence for fractional quantum Hall states. Most notably,
we find two distinct singlet states at the filling nu =2/3 for different
interactions. One of these states is accounted for by the composite fermion
theory while the other one is a paired state for which we identify two
competing descriptions with different topological structure. This paired state
may be an Abelian liquid of composite spin-singlet Bose molecules with Laughlin
correlations. Alternatively, it may be a known non-Abelian paired state,
indicated by good overlaps with the corresponding trial wavefunction. By fine
tuning of the scattering lengths it is possible to create the non-Abelian
critical Haldane-Rezayi state for nu =1/2 and the permanent state of Moore and
Read for nu =1. For purely repulsive interactions, we also find evidence for a
gapped Halperin state at nu=2/5.


title: Planar spin network coherent states II. Small corrections

abstract:
  This paper is the second of two which construct coherent states for spin
networks with planar symmetry. Paper 1 constructs set of coherent states peaked
at specific values of holonomy and triad. These operators acting on the
coherent state give back the coherent state plus small correction (SC) states.
The present paper proves that these SC states form a complete subset of the
overcomplete set of coherent states. The subset is used to construct a
perturbation expansion of the inverse of the volume operator. Appendices
calculate the standard deviations of the angles occurring in the holonomies,
demonstrate that standard deviations are given by matrix elements of the SC
states, and estimate the rate of spreading of a coherent state wave packet.


title: KPZ formula for log-infinitely divisible multifractal random measures

abstract:
  We consider the continuous model of log-infinitely divisible multifractal
random measures (MRM) introduced in \cite{bacry} . If M is a non degenerate
multifractal measure with associated metric $\rho(x,y)=M([x,y])$ and structure
function $\zet a$, we show that we have the following relation between the
(Euclidian) Hausdorff dimension ${\rm dim}_H$ of a measurable set K and the
Hausdorff dimension ${\rm dim}_H^{\rho}$ with respect to \rho of the same set:
$\zeta({\rm dim}_H^{\rho}(K))={\r m dim}_H(K)$. Our results can be extended to
higher dimensions in the log normal case: inspired by quantum gravity in dime
nsion 2, we consider the 2 dimensional case.


title:
Local moment versus Kondo behavior of the 4f-electrons in rare-earth
  iron oxypnictides

abstract:
  We consider the role played by the 4f states in the rare-earth oxyarsenides
REOFeAs (RE=Ce,Pr,Nd) and the oxyphosphate CeOFeP, using a first-principles
technique that combines the local density approximation and dynamical
mean-field theory (LDA+DMFT). In the Pr and Nd compounds, the 4f states are
located well below and above the Fermi level E_F, and essentially do not
interact with the iron 3d bands located near E_F, resulting in local moment
behavior. In the Ce compounds, our results reveal a qualitatively different
picture, with the 3d-4f hybridization being sufficiently strong to give rise to
an observable Kondo screening of the local 4f moment. Our LDA+DMFT electronic
structure calculations allow us to estimate the Kondo temperature T_K for both
CeOFeP and CeOFeAs. For the phosphate, the order of magnitude of our estimate
is consistent with the experimental observation of T_K around 10 K. At ambient
pressure, T_K is found to be negligibly small for CeOFeAs. Under applied
hydrostatic pressure, we predict an exponential increase of T_K which reaches
values comparable to the superconducting T_c around 40 K at pressures above 10
GPa. We conjecture that the competition between the Kondo effect and
superconductivity may be at the origin of the monotonous decrease of T_c
observed in CeOFeAs under pressure. We argue that the quantitative aspects of
this competition are inconsistent with a weak-coupling BCS description of the
superconductivity in the oxyarsenides.


title:
Di-Jet Conical Correlations Associated with Heavy Quark Jets in anti--de
  Sitter Space/Conformal Field Theory Correspondence

abstract:
  We show that far zone Mach and diffusion wake ``holograms'' produced by
supersonic strings in anti--de Sitter space/conformal field theory (AdS/CFT)
correspondence do not lead to observable conical angular correlations in the
strict $N_c\to\infty$ supergravity limit if Cooper-Frye hadronization is
assumed. However, a special {\em nonequilibrium} ``neck'' zone near the jet is
shown to produce an apparent sonic boom azimuthal angle distribution that is
roughly independent of the heavy quark's velocity. Our results indicate that a
measurement of the dependence of the away-side correlations on the velocity of
associated identified heavy quark jets at the BNL Relativistic Heavy Ion
Collider and CERN LHC will provide a direct test of the nonperturbative
dynamics involved in the coupling between jets and the strongly-coupled
Quark-Gluon Plasma (sQGP) implied by AdS/CFT correspondence.


title: Keynotes on membrane proteomics

abstract:
  This review article deals with the specificities of the proteomics analysis
of membrane proteins.


title:
Optical spectroscopy of superconducting Ba{0.55}K{0.45}Fe2As2: evidence
  for strong coupling to low energy bosons

abstract:
  Optical spectroscopy on single crystals of the new iron arsenide
superconductor Ba{0.55}K{0.45}Fe2As2 shows that the infrared spectrum consists
of two major components: a strong metallic Drude band and a well separated mid
infrared absorption centered at 0.7 eV. It is difficult to separate the two
components unambiguously but several fits of Lorentzian peaks suggest a model
with a Drude peak having a plasma frequency of 1.8 to 2.1 eV and a midinfrared
peak with a plasma frequency of 2.5 eV. In contrast to the cuprate
superconductors the scattering rate obtained from the extended Drude model
saturates at 150 meV as compared to 500 meV for a typical cuprate. Detailed
analysis of the frequency dependent scattering rate shows that the charge
carriers interact with broad bosonic spectrum with a peak at 25 meV and a
coupling constant lambda =approx 2 at low temperature. As the temperature
increases this coupling weakens to lambda=0.6 at ambient temperature. This
suggests a bosonic spectrum that is similar to what is seen in the lower Tc
cuprates.


title: Oxidative stress response: a proteomic view

abstract:
  The oxidative stress response is characterized by various effects on a range
of biologic molecules. When examined at the protein level, both expression
levels and protein modifications are altered by oxidative stress. While these
effects have been studied in the past by classic biochemical methods, the
recent onset of proteomics methods has allowed the oxidative stress response to
be studied on a much wider scale. The input of proteomics in the study of
oxidative stress response and in the evidence of an oxidative stress component
in biologic phenomena is reviewed in this paper.


title: Hydrodynamic turbulence and intermittent random fields

abstract:
  In this article, we construct two families of nonsymmetrical multifractal
fields. One of these families is used for the modelization of the velocity
field of turbulent flows.


title: On the Classical Limit of Spin Network Gravity: Two Conjectures

abstract:
  Estimates are given of the time scales which govern spreading of a coherent
state wave packet. The estimates, based on dimensional analysis, suggest that
spreading should be small for coherent states with average angular momentum of
order 100 or larger. It is conjectured that in the classical limit, terms in
the Hamiltonian which add a new vertex will be suppressed, compared to terms
which modify the existing spin network without changing the number of vertices.


title:
Muon spin relaxation studies of magnetic order and superfluid density in
  antiferromagnetic NdOFeAs, BaFe2As2 and superconducting (Ba,K)Fe2As2

abstract:
  Zero-field (ZF) muon spin relaxation ($\mu$SR) measurements have revealed
static commensurate magnetic order of Fe moments in NdOFeAs below $T_{N} \sim
135$ K, with the ordered moment size nearly equal to that in LaOFeAs, and
confirmed similar behavior in BaFe$_{2}$As$_{2}$. In single crystals of
superconducting (Ba$_{0.55}$K$_{0.45}$)Fe$_{2}$As$_{2}$, $\mu$SR spectra
indicate static magnetism with incommensurate or short-ranged spin structure in
$\sim$ 70 % of volume below $T_{N} \sim$ 80 K, coexisting with remaining volume
which exhibits superfluid-response consistent with nodeless gap below
$T_{c}\sim 30$ K.


title: $AC(\sigma)$ operators

abstract:
  In this paper we present a new extension of the theory of well-bounded
operators to cover operators with complex spectrum. In previous work a new
concept of the class of absolutely continuous functions on a nonempty compact
subset $\sigma$ of the plane, denoted $AC(\sigma)$, was introduced. An
$\AC(\sigma)$ operator is one which admits a functional calculus for this
algebra of functions. The class of $AC(\sigma)$ operators includes all of the
well-bounded operators and trigonometrically well-bounded operators, as well as
all scalar-type spectral operators, but is strictly smaller than Berkson and
Gillespie's class of $AC$ operators. This paper develops the spectral
properties of $AC(\sigma)$ operators and surveys some of the problems which
remain in extending results from the theory of well-bounded operators.


title: Higgs versus Matter in the Heterotic Landscape

abstract:
  In supersymmetric extensions of the standard model there is no basic
difference between Higgs and matter fields, which leads to the well known
problem of potentially large baryon and lepton number violating interactions.
Although these unwanted couplings can be forbidden by continuous or discrete
global symmetries, a theoretical guiding principle for their choice is missing.
We examine this problem for a class of vacua of the heterotic string
compactified on an orbifold. As expected, in general there is no difference
between Higgs and matter. However, certain vacua happen to possess unbroken
matter parity and discrete $R$-symmetries which single out Higgs fields in the
low energy effective field theory. We present a method how to identify maximal
vacua in which the perturbative contribution to the $\mu$-term and the
expectation value of the superpotential vanish. Two vacua are studied in
detail, one with two pairs of Higgs doublets and one with partial gauge-Higgs
unification.


title:
Reduction of superintegrable systems: the anisotropic harmonic
  oscillator

abstract:
  We introduce a new 2N--parametric family of maximally superintegrable systems
in N dimensions, obtained as a reduction of an anisotropic harmonic oscillator
in a 2N--dimensional configuration space. These systems possess closed bounded
orbits and integrals of motion which are polynomial in the momenta. They
generalize known examples of superintegrable models in the Euclidean plane.


title:
How the surrounding water changes the electronic and magnetic properties
  of DNA

abstract:
  Strong influence of water molecules on the transport and magnetic properties
of DNA, observed in this study, opens up real opportunities for application of
DNA in molecular electronics. Interaction of the nucleobases with water
molecules leads to breaking of some of the $\pi$ bonds and appearance of
unbound pi electrons. These unbound electrons contribute significantly to the
charge transfer at room temperature by up to 1000 times, but at low temperature
the efficiency of charge transfer is determined by the spin interaction of the
two unbound electrons located on the intrastrand nucleobases. The charge
exchange between the nucleobases is allowed only when the spins of unbound
electrons are antiparallel. Therefore, the conductance of the DNA molecule can
be controlled by a magnetic field. That effect has potential applications for
developing a nanoscale spintronic device based on the DNA molecule, where
efficiency of spin interaction will be determined by the DNA sequence.


title:
Characterizing the velocity field in hydrodynamical simulations of
  low-mass star formation using spectral line profiles

abstract:
  When low-mass stars form, the collapsing cloud of gas and dust goes through
several stages which are usually characterized by the shape of their spectral
energy distributions. Such classification is based on the cloud morphology only
and does not address the dynamical state of the object. In this paper we
investigate the initial cloud collapse and subsequent disk formation through
the dynamical behavior as reflected in the sub-millimeter spectral emission
line profiles. If a young stellar object is to be characterized by its
dynamical structure it is important to know how accurately information about
the velocity field can be extracted and which observables provide the best
description of the kinematics. Of particular interest is the transition from
infalling envelope to rotating disk, because this provides the initial
conditions for the protoplanetary disk, such as mass and size. We use a
hydrodynamical model, describing the collapse of a core and formation of a
disk, to produce synthetic observables which we compare to calculated line
profiles of a simple parameterized model. Because we know the velocity field
from the hydrodynamical simulation we can determine in a quantitative way how
well our best-fit parameterized velocity field reproduces the original. We use
a molecular line excitation and radiation transfer code to produce spectra of
both our hydro dynamical simulation as well as our parameterized model. We find
that information about the velocity field can reasonably well be derived by
fitting a simple model to either single-dish lines or interferometric data, but
preferentially by using a combination of the two. Our result shows that it is
possible to establish relative ages of a sample of young stellar objects using
this method, independently of the details of the hydrodynamical model.


title: Chirped-pulse oscillators: an impact of the dynamic gain saturation

abstract:
  An effect of the dynamic gain saturation on chirped-pulse oscillator was
investigated. It was found, that the dynamic gain saturation causes strong
perturbations of the pulse front that destabilizes an oscillator. As a result,
the chirped-pulse exists only within some limited range of dispersions and
there is a limit of energy growth for a given resonator period.


title:
Quasi Normal Modes description of transmission properties for Photonic
  Band Gap structures

abstract:
  In this paper, we use the 'Quasi Normal Modes' (QNM) approach for discussing
the transmission properties of double-side opened optical cavities: in
particular, this approach is specified for one dimensional (1D) 'Photonic Band
Gap' (PBG) structures. Moreover, we conjecture that the density of the modes
(DOM) is a dynamical variable which has the flexibility of varying with respect
to the boundary conditions as well as the initial conditions; in fact, the e.m.
field generated by two monochromatic counter-propagating pump waves leads to
interference effects inside a quarter-wave (QW) symmetric 1D-PBG structure.
Finally, here, for the first time, a large number of theoretical assumptions on
QNM metrics for an open cavity, never discussed in literature, are proved, and
a simple and direct method to calculate the QNM norm for a 1D-PBG structure is
reported.


title: Compact $AC(\sigma)$ operators

abstract:
  All compact $AC(\sigma)$ operators have a representation analogous to that
for compact normal operators. As a partial converse we obtain conditions which
allow one to construct a large number of such operators. Using the results in
the paper, we answer a number of questions about the decomposition of a compact
$AC(\sigma)$ into real and imaginary parts.


title:
On the kinetic equation of linear fractional stable motion and
  applications to modeling the scaling of intermittent bursts

abstract:
  Levy flights and fractional Brownian motion (fBm) have become exemplars of
the heavy tailed jumps and long-ranged memory widely seen in physics. 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 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 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 and elsewhere.


title: Light scalar mesons in the soft-wall model of AdS/QCD

abstract:
  We study light scalar mesons in the AdS/QCD soft-wall model with a background
dilaton field. The masses and decay constants are compatible with experiment
and QCD determinations if $a_0(980)$ and $f_0(980)$ are identified as the
lightest scalar mesons; moreover, the states are organized in linear Regge
trajectories with the same slope of vector mesons. Comparing the two-point
correlation function of scalar operators in AdS and QCD, information about the
condensates can be derived. Strong couplings of scalar states to pairs of light
pseudoscalar mesons turn out to be small, at odds with experiment and QCD
estimates: this discrepancy is related to the description of chiral symmetry
breaking in this model.


title:
Shoot regeneration seedlings from transverse thin cell layer explants
  excised from cotyledon, petiole, hypocotyl of [{Brassica juncea} L. Czern.]
  in the presence of CdCl$_2$

abstract:
  The present work describes a novel neoformation process of \textit{Brassica
juncea} (L.) Czern. seedlings from transverse thin cell layers in the presence
of CdCl$_2$. In order to investigate the regeneration ability of this crop, the
effect of CdCl$_2$ on shoot regeneration (frequency of regeneration and bud
number per tTCL) was examined. The tTCL explants were excised from cotyledon,
petiole and hypocotyl of 7 day-old \textit{B. juncea} seedlings and cultivated
on a solid basal MS medium supplemented with $\alpha $-naphtalenacetic acid
(NAA : 3.22 $\mu$M), 6-benzylamino-purine (BAP : 26.6 $\mu$M), sucrose (2 %,
w/v), silver nitrate (AgNO3 : 10 $\mu$M) and various concentrations of CdCl$_2$
(0 - 250 $\mu$M). A concentration of CdCl$_2$ of 5 $\mu$M is enough to reduce
significantly the percentage of regenerated tTCL from 95-100 % to 77-86 % for
all organs tested. In addition, 5 $\mu$M of CdCl$_2$ reduces the bud number
from 4.5 to 2.98 and 3.2 to 2.02 of hypocotyl and petiole tTCLs, but not for
cotyledon tTCLs. Besides, 250 $\mu$M of CdCl$_2$ is lethal for all tTCLs
whatever the organ, and 200 $\mu$M is lethal only for cotyledon and petiole
tTCLs but not for hypocotyl explants which had 3.6 % of frequency of shoot
regeneration. Plantlets regenerated from all shoots, whatever the treatment,
developed and flowered normally 6 weeks after the transfer to pots. The
regenerated plants were fertile and identical to source plants.


title: The GMRT EoR Experiment: Limits on Polarized Sky Brightness at 150 MHz

abstract:
  The GMRT reionization effort aims to map out the large scale structure of the
Universe during the epoch of reionization (EoR). Removal of polarized Galactic
emission is a difficult part of any 21 cm EoR program, and we present new upper
limits to diffuse polarized foregrounds at 150 MHz. We find no high
significance evidence of polarized emission in our observed field at mid
galactic latitude (J2000 08h26m+26). We find an upper limit on the
2-dimensional angular power spectrum of diffuse polarized foregrounds of [l^2
C_l/(2 PI)]^{1/2}< 3K in frequency bins of width 1 MHz at 300<l<1000. The
3-dimensional power spectrum of polarized emission, which is most directly
relevant to EoR observations, is [k^3 P_p(k)/(2 PI^2)]^{1/2}< 2K at k_perp >
0.03 h/Mpc, k < 0.1 h/Mpc. This can be compared to the expected EoR signal in
total intensity of [k^3 P(k)/ (2 PI^2) ]^{1/2} ~ 10 mK. We find polarized
structure is substantially weaker than suggested by extrapolation from higher
frequency observations, so the new low upper limits reported here reduce the
anticipated impact of these foregrounds on EoR experiments. We discuss Faraday
beam and depth depolarization models and compare predictions of these models to
our data. We report on a new technique for polarization calibration using
pulsars, as well as a new technique to remove broadband radio frequency
interference. Our data indicate that, on the edges of the main beam at GMRT,
polarization squint creates ~ 3% leakage of unpolarized power into polarized
maps at zero rotation measure. Ionospheric rotation was largely stable during
these solar minimum night time observations.


title: Time-dependent CO depletion during the formation of protoplanetary disks

abstract:
  Understanding the gas abundance distribution is essential when tracing star
formation using molecular line observations. Changing density and temperature
conditions cause gas to freeze-out onto dust grains, and this needs to be taken
into account when modeling a collapsing molecular cloud. This study aims to
provide a realistic estimate of the CO abundance distribution throughout the
collapse of a molecular cloud. We provide abundance profiles and synthetic
spectral lines which can be compared to observations. We use a 2D
hydrodynamical simulation of a collapsing cloud and subsequent formation of a
protoplanetary disk as input for the chemical calculations. From the resulting
abundances, synthetic spectra are calculated using a molecular excitation and
radiation transfer code. We compare three different methods to calculate the
abundance of CO. Our models also consider cosmic ray desorption and the effects
of an increased CO binding energy. The resulting abundance profiles are
compared to observations from the literature and are found to agree well. The
resulting abundance profiles agree well with analytic approximations, and the
corresponding line fluxes match observational data. Our developed method to
calculate abundances in hydrodynamical simulations should greatly aid in
comparing these to observations, and can easily be generalized to include
gas-phase reaction networks.


title: top2008 Conference Summary

abstract:
  This is a summary of the talks presented at the International Workshop on Top
Quark Physics (top2008) held in Elba, Italy, May 18-24, 2008.


title:
Potential Phytoextraction with in-vitro regenerated plantlets of
  Brassica juncea (L.) Czern. in presence of CdCl$_2$: Cadmium accumulation and
  physiological parameter measurement

abstract:
  Heavy metal contamination of agricultural land is partly responsible for
limiting crop productivity. Cd$^{2+}$ is known as a non-essentiel HM that can
be harmful to plants even at low concentrations. Brassica juncea (L.) is able
to accumulate more than 400 $\mu$g.g$^{-1}$ D.W. in the shoot, a physiological
trait which may be exploited for the phytoremediation of contaminated soils and
waters. . The application of 75 $\mu$M CdCl$_2$ for three days does not show
any effect in the B. juncea growth parameters (F.W. and D.W.) whatever the type
of plantlets. This application decreases also the contents of chlorophyll a,
carotenoids and Chl a/b ratio (2.26) for plantlets regenerated in the absence
of CdCl$_2$ but not those of plantlets regenerated in its presence. Roots have
the highest contents (3071; 1544 $\mu$g.g$^{-1}$ D.W.) followed by stems (850;
687$\mu$g.g$^{-1}$ D.W.) and leaves (463; 264$\mu$g.g$^{-1}$ D.W.)
respectively. In our conditions, we suggest that the low accumulation in the
plantlets regenerated in the presence of CdCl$_2$ by the means of in-vitro
regeneration technology is still benefical, to some extent, for the
phytoextraction process and seems to be an interesting technology that allows
the cultivation of these plantlets in contaminated soils with low accumulation
of metal in their shoots and probably in their seeds used in many food
technologies.


title:
Magnetoresistance and collective Coulomb blockade in super-lattices of
  ferromagnetic CoFe nanoparticles

abstract:
  We report on transport properties of millimetric super-lattices of CoFe
nanoparticles surrounded by organic ligands. R(T)s follow R(T) =
R_0.exp(T/T_0)^0.5 with T_0 ranging from 13 to 256 K. At low temperature I(V)s
follow I=K[(V-V_T)/V_T]^ksi with ksi ranging 3.5 to 5.2. I(V) superpose on a
universal curve when shifted by a voltage proportional to the temperature.
Between 1.8 and 10 K a high-field magnetoresistance with large amplitude and a
strong voltage-dependence is observed. Its amplitude only depends on the
magnetic field/temperature ratio. Its origin is attributed to the presence of
paramagnetic states present at the surface or between the nanoparticles. Below
1.8 K, this high-field magnetoresistance abruptly disappears and inverse
tunnelling magnetoresistance is observed, the amplitude of which does not
exceed 1%. At this low temperature, some samples display in their I(V)
characteristics abrupt and hysteretic transitions between the Coulomb blockade
regime and the conductive regime. The increase of the current during these
transitions can be as high as a factor 30. The electrical noise increases when
the sample is near the transition. The application of a magnetic field
decreases the voltage at which these transitions occur so magnetic-field
induced transitions are also observed. Depending on the applied voltage, the
temperature and the amplitude of the magnetic field, the magnetic-field induced
transitions are either reversible or irreversible. These abrupt and hysteretic
transitions are also observed in resistance-temperature measurements. They
could be the soliton avalanches predicted by Sverdlov et al. [Phys. Rev. B 64,
041302 (R), 2001] or could also be interpreted as a true phase transition
between a Coulomb glass phase to a liquid phase of electrons.


title:
Micropropagation of three genotypes of Indian mustard [{Brassica juncea}
  (L.) Czern.] using seedling-derived transverse thin cell layer (tTCL)
  explants

abstract:
  Micropropagation of three genotypes of Indian mustard [\textit{Brassica
juncea} (L.) Czern.] using 7-days old seedling-derived transverse thin cell
layer (tTCL) explants was accomplished.
  The genotype, explant source and addition of silver nitrate to the medium
significantly influenced shoot bud induction. MS medium with 26.6 $\mu$M of
6-Benzylaminopurin (BAP) and 3.22 $\mu$M of 1-naphtaleneacetic acid (NAA) was
identical (in the case of cotyledon tTCLs whatever the organ) and superior for
the induction of buds (in the cases of petiole tTCL explants of genotypes 1 and
2 and hypocotyl tTCL explants of genotypes 1 and 3) than 53.3 $\mu$M of BAP and
3.22 $\mu$M of NAA. However, 53.3 $\mu$M of BAP was superior for the induction
of buds than 26.6 $\mu$M in the presence of the same concentration of NAA for
petiole tTCL explants of genotype 3 and hypocotyl tTCL explants of genotype 2.
  The addition of silver nitrate significantly enhanced the rate of shoot
induction in all genotypes. Cotyledon-derived tTCL explants exhibited the
highest shoot bud induction potential and was followed by petiole- and
hypocotyl-derived ones. Addition of 10 $\mu$M of silver nitrate to BAP and NAA
supplemented medium induced higher frequency shoot bud induction (up to 100 %)
with the highest means of 4.45 shoots per cotyledon-derived tTCL explants
obtained with the genotype 2. Shoot regenerated were rooted on MS basal medium
without PGRs which induced 99 % of roots per shoot. The plantlets established
in greenhouse conditions with 99 % survival, flowered normally and set seeds.


title: VSI: the VLTI spectro-imager

abstract:
  The VLTI Spectro Imager (VSI) was proposed as a second-generation instrument
of the Very Large Telescope Interferometer providing the ESO community with
spectrally-resolved, near-infrared images at angular resolutions down to 1.1
milliarcsecond and spectral resolutions up to R=12000. Targets as faint as K=13
will be imaged without requiring a brighter nearby reference object. The unique
combination of high-dynamic-range imaging at high angular resolution and high
spectral resolution enables a scientific program which serves a broad user
community and at the same time provides the opportunity for breakthroughs in
many areas of astrophysic including: probing the initial conditions for planet
formation in the AU-scale environments of young stars; imaging convective cells
and other phenomena on the surfaces of stars; mapping the chemical and physical
environments of evolved stars, stellar remnants, and stellar winds; and
disentangling the central regions of active galactic nuclei and supermassive
black holes. VSI will provide these new capabilities using technologies which
have been extensively tested in the past and VSI requires little in terms of
new infrastructure on the VLTI. At the same time, VSI will be able to make
maximum use of new infrastructure as it becomes available; for example, by
combining 4, 6 and eventually 8 telescopes, enabling rapid imaging through the
measurement of up to 28 visibilities in every wavelength channel within a few
minutes. The current studies are focused on a 4-telescope version with an
upgrade to a 6-telescope one. The instrument contains its own fringe tracker
and tip-tilt control in order to reduce the constraints on the VLTI
infrastructure and maximize the scientific return.


title: On Geometry of the R\"ossler system of equations

abstract:
  On a basis of theory of Riemann extension of the space of constant affine
connection associated with the R\"ossler system of equations relations between
its parameters are investigated.


title: Static Universe: Infinite, Eternal and Self-Sustainable

abstract:
  In this work, we present a study like a "stellar dynamics" model of an
infinite Universe, in which the matter distribution follow a relationship
inversely proportional to the square power with respect to the distance from
the center of rotation of cluster and supercluster of galaxies (that have a
common centre of rotation). In this study, we considered that the Universe have
infinite centers similar in structure and in dynamic equilibrium between them.
The stars in the galaxies are supposed to be homogeneously distributed with a
spherical symmetry and with an average radius and, in turn, the galaxies in the
Universe. Also, we consider a smoothed potential of this kind of universe and
study the effect of gravity in the radiation of the stars: applying the
equivalence principle we obtain a mathematical expression for the Hubble's law
and a formula for its redshift that could explain this phenomenon like a
gravitational effect. Also we obtain an approximated calculation of the Cosmic
Background Radiation (CBR), taking as hypothesis that this radiation is the
light of all stars in the Universe that arrive until us with an extreme
gravitational redshift. In conclusion, we present here an alternative
explanation for the redshift and CBR, like an alternative to the presented by
the Big Bang theory, or Steady State theory, postulating in consequence a new
theory about the structure of the Universe: static, infinite, eternal and
self-sustainable.


title:
Differential forms on Wasserstein space and infinite-dimensional
  Hamiltonian systems

abstract:
  Let M denote the space of probability measures on R^D endowed with the
Wasserstein metric. A differential calculus for a certain class of absolutely
continuous curves in M was introduced by Ambrosio, Gigli and Savare'. In this
paper we develop a calculus for the corresponding class of differential forms
on M. In particular we prove an analogue of Green's theorem for 1-forms and
show that the corresponding first cohomology group, in the sense of de Rham,
vanishes. For D=2d we then define a symplectic distribution on M in terms of
this calculus, thus obtaining a rigorous framework for the notion of
Hamiltonian systems as introduced by Ambrosio and Gangbo. Throughout the paper
we emphasize the geometric viewpoint and the role played by certain
diffeomorphism groups of R^D.


title:
Global regularity and probabilistic schemes for free boundary surfaces
  of multivariate American derivatives and their Greeks

abstract:
  In a rather general setting of multivariate stochastic volatility market
models we derive global iterative probabilistic schemes for computing the free
boundary and its Greeks for a generic class of American derivative models using
front-fixing methods. Convergence is closely linked to a proof of global
regularity of the free boundary surface.


title:
The XMM-Newton Serendipitous Survey. V. The Second XMM-Newton
  Serendipitous Source Catalogue

abstract:
  Aims: Pointed observations with XMM-Newton provide the basis for creating
catalogues of X-ray sources detected serendipitously in each field. This paper
describes the creation and characteristics of the 2XMM catalogue. Methods: The
2XMM catalogue has been compiled from a new processing of the XMM-Newton EPIC
camera data. The main features of the processing pipeline are described in
detail. Results: The catalogue, the largest ever made at X-ray wavelengths,
contains 246,897 detections drawn from 3491 public XMM-Newton observations over
a 7-year interval, which relate to 191,870 unique sources. The catalogue fields
cover a sky area of more than 500 sq.deg. The non-overlapping sky area is ~360
sq.deg. (~1% of the sky) as many regions of the sky are observed more than once
by XMM-Newton. The catalogue probes a large sky area at the flux limit where
the bulk of the objects that contribute to the X-ray background lie and
provides a major resource for generating large, well-defined X-ray selected
source samples, studying the X-ray source population and identifying rare
object types. The main characteristics of the catalogue are presented,
including its photometric and astrometric properties .


title: Z-prime Searches at the LHC: Some QCD Precision Studies in Drell-Yan

abstract:
  Discovery potentials for extra neutral interactions at the Large Hadron
Collider in forthcoming experiments are analyzed in Drell-Yan. For this purpose
we use high precision next-to-next-to-leading order (NNLO) determination of the
mass invarian distributions and of the total cross sections in the kinematic
region around 1 TeV. In this region we explore the possibility to make a
preliminary distinction between different anomaly-free extentions of the
Standard Model.


title: Exploring the evolutionary paths of the most massive galaxies since z~2

abstract:
  We use Spitzer MIPS data from the FIDEL Legacy Project in the Extended Groth
Strip to analyze the stellar mass assembly of massive (M>10^11 M_sun) galaxies
at z<2 as a function of structural parameters. We find 24 micron emission for
more than 85% of the massive galaxies morphologically classified as disks, and
for more than 57% of the massive systems morphologically classified as
spheroids at any redshift, with about 8% of sources harboring a bright X-ray
and/or infrared emitting AGN. More noticeably, 60% of all compact massive
galaxies at z=1-2 are detected at 24 micron, even when rest-frame optical
colors reveal that they are dead and evolving passively. For spheroid-like
galaxies at a given stellar mass, the sizes of MIPS non-detections are smaller
by a factor of 1.2 in comparison with IR-bright sources. We find that disk-like
massive galaxies present specific SFRs ranging from 0.04 to 0.2 Gyr^-1 at z<1
(SFRs ranging from 1 to 10 M_sun/yr), typically a factor of 3-6 higher than
massive spheroid-like objects in the same redshift range. At z>1, and more
pronouncedly at z>1.3, the median specific SFRs of the disks and spheroids
detected by MIPS are very similar, ranging from 0.1 to 1 Gyr^-1 (SFR=10-200
M_sun/yr). We estimate that massive spheroid-like galaxies may have doubled (at
the most) their stellar mass from star-forming events at z<2: less than 20%
mass increase at 1.7<z<2.0, up to 40% more at 1.1<z<1.7, and less than 20%
additional increase at z<1. Disk-like galaxies may have tripled (at the most)
their stellar mass at z<2 from star formation alone: up to 40% mass increase at
1.7<z<2.0, and less than 180% additional increase below z=1.7 occurred at a
steady rate.


title: Random Matrices and Chaos in Nuclear Physics

abstract:
  The authors review the evidence for the applicability of random--matrix
theory to nuclear spectra. In analogy to systems with few degrees of freedom,
one speaks of chaos (more accurately: quantum chaos) in nuclei whenever
random--matrix predictions are fulfilled. An introduction into the basic
concepts of random--matrix theory is followed by a survey over the extant
experimental information on spectral fluctuations, including a discussion of
the violation of a symmetry or invariance property. Chaos in nuclear models is
discussed for the spherical shell model, for the deformed shell model, and for
the interacting boson model. Evidence for chaos also comes from random--matrix
ensembles patterned after the shell model such as the embedded two--body
ensemble, the two--body random ensemble, and the constrained ensembles. All
this evidence points to the fact that chaos is a generic property of nuclear
spectra, except for the ground--state regions of strongly deformed nuclei.


title:
Effective Theory of Magnetization Plateaux in the Shastry-Sutherland
  Lattice

abstract:
  We use the non-perturbative Contractor-Renormalization method (CORE) in order
to derive an effective model for triplet excitations on the Shastry-Sutherland
lattice. For strong enough magnetic fields, various magnetization plateaux are
observed, e.g. at 1/8, 1/4, 1/3 of the saturation, as found experimentally in a
related compound. Moreover, other stable plateaux are found at 1/9, 1/6 or 2/9.
We give a critical review of previous works and try to resolve some apparent
inconsistencies between various theoretical approaches.


title: Discrete time nonlinear filters with informative observations are stable

abstract:
  The nonlinear filter associated with the discrete time signal-observation
model $(X_k,Y_k)$ is known to forget its initial condition as $k\to\infty$
regardless of the observation structure when the signal possesses sufficiently
strong ergodic properties. Conversely, it stands to reason that if the
observations are sufficiently informative, then the nonlinear filter should
forget its initial condition regardless of any properties of the signal. We
show that for observations of additive type $Y_k=h(X_k)+\xi_k$ with invertible
observation function $h$ (under mild regularity assumptions on $h$ and on the
distribution of the noise $\xi_k$), the filter is indeed stable in a weak sense
without any assumptions at all on the signal process. If the signal satisfies a
uniform continuity assumption, weak stability can be strengthened to stability
in total variation.


title: A simple method for generating rational triangles

abstract:
  In the early part of the paper, various geometrical formulas are derived.
Then, at some point in the paper, the concept of a Pythagorean rational is
introduced. A Pythagorean rational is a rational number which is the ratio of
two integers which are the leglengths of a Pythagorean triangle. Using the idea
of Pythagorean rationals, we generate two families of rational triangles. We
define a rational triangle to be a triangle with rational sidelengths and area.


title: A Massive Study of M2-brane Proposals

abstract:
  We test the proposals for the worldvolume theory of M2-branes by studying its
maximally supersymmetric mass-deformation. We check the simplest prediction for
the mass-deformed theory on N M2-branes: that there should be a set of discrete
vacua in one-to-one correspondence with partitions on N. For the mass-deformed
Lorentzian three-algebra theory, we find only a single classical vacuum,
casting doubt on its M2-brane interpretation. For the mass-deformed ABJM
theory, we do find a discrete set of solutions, but these are more numerous
than predicted. We discuss possible resolutions of this puzzling discrepancy.
We argue that the classical vacuum solutions of the mass-deformed ABJM theory
display properties of fuzzy three-spheres, as expected from their gravitational
dual interpretation.


title: Thomas-Fermi Statistical Models of Finite Quark Matter

abstract:
  I introduce and discuss models of finite quark matter using the formalism of
the Thomas-Fermi statistical model. Similar to bag models, a vacuum energy term
is introduced to model long distance confinement, but the model produces bound
states from the residual color Coulomb attraction even in the absence of such a
term. I discuss three baryonic applications: an equal mass nonrelativistic
model with and without volume pressure, the ultra-relativistic limit confined
by volume pressure, and a color-flavor locking massless model. These model may
be extended to multi-meson and other mixed hadronic states. Hopefully, it can
help lead to a better understanding of the phenomenology of high multi-quark
states in preparation for more detailed lattice QCD calculations.


title:
Can a primordial magnetic field originate large-scale anomalies in WMAP
  data?

abstract:
  Several accurate analyses of the CMB temperature maps from the Wilkinson
Microwave Anisotropy Probe (WMAP) have revealed a set of anomalous results, at
large angular scales, that appears inconsistent with the statistical isotropy
expected in the concordance cosmological model $\Lambda$CDM. Because these
anomalies seem to indicate a preferred direction in the space, here we
investigate the signatures that a primordial magnetic field, possibly present
in the photon-baryon fluid during the decoupling era, could have produced in
the large-angle modes of the observed CMB temperature fluctuations maps. To
study these imprints we simulate Monte Carlo CMB maps, which are statistically
anisotropic due to the correlations between CMB multipoles induced by the
magnetic field. Our analyses reveal the presence of the North-South angular
correlations asymmetry phenomenon in these Monte Carlo maps, and we use these
information to establish the statistical significance of such phenomenon
observed in WMAP maps. Moreover, because a magnetic field produces planarity in
the low-order CMB multipoles, where the planes are perpendicular to the
preferred direction defined by the magnetic field, we investigate the
possibility that two CMB anomalous phenomena, namely the North-South asymmetry
and the quadrupole-octopole planes alignment, could have a common origin. Our
results, for large-angles, show that the correlations between low-order CMB
multipoles introduced by a sufficiently intense magnetic field, can reproduce
some of the large-angle anisotropic features mapped in WMAP data. We also
reconfirm, at more than 95% CL, the existence of a North-South power asymmetry
in the WMAP five-year data.


title: Spin and Lattice Structure of Single Crystal SrFe2As2

abstract:
  We use neutron scattering to study the spin and lattice structure on single
crystals of SrFe2As2, the parent compound of the FeAs based superconductor
(Sr,K)Fe2As2. We find that SrFe2As2 exhibits an abrupt structural phase
transitions at 220K, where the structure changes from tetragonal with lattice
parameters c > a = b to orthorhombic with c > a > b. At almost the same
temperature, Fe spins in SrFe2As2 develop a collinear antiferromagnetic
structure along the orthorhombic a-axis with spin direction parallel to this
a-axis. These results are consistent with earlier work on the RFeAsO (R = rare
earth elements) families of materials and on BaFe2As2, and therefore suggest
that static antiferromagnetic order is ubiquitous for the parent compound of
these FeAs-based high-transition temperature superconductors.


title: Crystalline representations of G_Qp^a with coefficients

abstract:
  This paper studies crystalline representations of G_K with coefficients of
any dimension, where K is the unramified extension of Q_p of degree a. We prove
a theorem of Fontaine-Laffaille type when \sigma-invariant Hodge-Tate weight
less than p-1, which establishes the bijection between Galois stable lattices
in crystalline representations and strongly divisible \phi-lattice. In
generalizing Breuil's work, we classify all reducible and irreducible
crystalline representations of G_K of dimensional 2, then describe their mod p
reductions. We generalize some results (of Deligne, Fontaine-Serre, and
Edixhoven) to representations arising from Hilbert modular forms when
\sigma-invariant Hodge-Tate weight less than p-1.


title:
Interpretation of the Arithmetic in certain groups of piecewise affine
  permutations of an interval

abstract:
  The Arithmetic is interpreted in all the groups of Richard Thompson and
Graham Higman, as well as in other groups of piecewise affine permutations of
an interval which generalize the groups of Thompson and Higman. In particular,
the elementary theories of all these groups are undecidable. Moreover,
Thompson's group $F$ and some of its generalizations interpret the Arithmetic
without parameters.


title:
Identification of Extra Neutral Gauge Bosons at the LHC Using b- and
  t-Quarks

abstract:
  New Neutral Gauge Bosons, Z' 's, are predicted by many models of physics
beyond the Standard Electroweak Theory. It is possible that a Z' would be
discovered early in the Large Hadron Collider program. The next step would be
to measure its properties to identify the underlying theory that gave rise to
the Z'. Heavy quarks have the unique property that they can be identified in
the final states. In this letter we demonstrate that measuring Z' decays to b-
and t-quark final states can act as an effective means of discriminating
between models with extra gauge bosons.


title:
Nonlinear Differential Equations Satisfied by Certain Classical Modular
  Forms

abstract:
  A unified treatment is given of low-weight modular forms on \Gamma_0(N),
N=2,3,4, that have Eisenstein series representations. For each N, certain
weight-1 forms are shown to satisfy a coupled system of nonlinear differential
equations, which yields a single nonlinear third-order equation, called a
generalized Chazy equation. As byproducts, a table of divisor function and
theta identities is generated by means of q-expansions, and a transformation
law under \Gamma_0(4) for the second complete elliptic integral is derived.
More generally, it is shown how Picard-Fuchs equations of triangle subgroups of
PSL(2,R) which are hypergeometric equations, yield systems of nonlinear
equations for weight-1 forms, and generalized Chazy equations. Each triangle
group commensurable with \Gamma(1) is treated.


title:
Particle Multiplicity in Jets and Sub-jets with Jet Axis from Color
  Current

abstract:
  We study the particle multiplicity in a jet or sub-jet as derived from an
energy-multiplicity 2-particle correlation. This definition avoids the notion
of a globally fixed jet axis and allows for the study of smaller jet cone
openings in a more stable way. The results are sensitive to the mean color
current $<C >_{A_0} $ in the jet from primary parton $A_0$ which takes into
account intermediate partonic processes in the sub-jet production where $C_F< <
C >_{A_0} < N_c$ at high energies. We generalize previous calculations in
Leading Logarithmic Approximation (LLA). The size of the effects related to
this jet axis definition are computed for multiplicities in sub-jets with
different opening angles and energies by including contributions from the
Modified LLA (MLLA) and Next-to-MLLA to the leading order QCD results.


title: Magnetic activity in the young star SAO 51891

abstract:
  We present preliminary results on a study based on contemporaneous
photometric and spectroscopic observations of the young K0-1V star SAO 51891.
We find that SAO 51891, a possible member of the Local Association, shows
emission cores in the CaII H&K and fillings in the Halpha and CaII Infra-Red
Triplet (IRT) lines. Moreover, we detect absorption lines of HeI-D3 and LiI and
measure a v sini of 19 km/s. A clear rotational modulation of both the light
and the photospheric temperature, due to photospheric spots, has been detected.
The net Halpha chromospheric emission does not show any detectable variation,
while the CaII IRT emission displays a fair modulation.


title:
Microscopic study of the effect of impurities on the first order spin
  density wave transition in BaFe$_2$As$_2$

abstract:
  We report an $^{75}$As NMR study of BaFe$_2$As$_2$ in both single crystals
and polycrystal forms. We find that Sn impurities in the single crystal
dramatically alter the low energy spin fluctuations and suppress the ordering
temperature from 138 K to 85 K. In contrast to Sn-free samples, we find that
the temperature dependence of the $^{75}$As NMR spectra and spin lattice
relaxation rates reveal a second order phase transition to a state of
incommensurate magnetic order.


title: True solar analogues in the open cluster M67

abstract:
  The solar analogues are fundamental targets for a better understanding of our
Sun and Solar System. Notwithstanding the efforts, this research is usually
limited to field stars. The open cluster M67 offers a unique opportunity to
search for solar analogues because its chemical composition and age are very
similar to those of our star. In this work, we analyze FLAMES@VLT spectra of
about one hundred of M67 main sequence stars with the aim to identify solar
analogues. We first determine cluster members which are likely not binaries, by
combining both proper motions and radial velocity measurements. Then, we
concentrate our analysis on the determination of stellar effective temperature,
using the analyzes of line-depth ratios and Halpha wings. Finally, we also
compute lithium abundance for all the stars. Thanks to the our analysis, we
find ten solar analogues, which allow us to derive a solar color
(B-V)=0.649+/-0.016 and a cluster distance modulus of 9.63+/-0.08, very close
to values found by previous authors. Among them, five are the best solar twins
with temperature determinations within 60 K from the solar values. Our results
lead us to do further spectroscopic investigations because the solar analogues
candidates are suitable for planet search.


title:
Observation of the bottomonium ground state in the decay Upsilon(3S) ->
  gamma eta_b

abstract:
  We report the results of a search for the bottomonium ground state eta_b(1S)
in the photon energy spectrum with a sample of (109 +/- 1) million of
Upsilon(3S) recorded at the Upsilon(3S) energy with the BABAR detector at the
PEP-II B factory at SLAC. We observe a peak in the photon energy spectrum at
E_gamma = 921.2 {+2.1} {-2.8} (stat) +/- 2.4(syst) MeV with a significance of
10 standard deviations. We interpret the observed peak as being due to
monochromatic photons from the radiative transition Upsilon(3S) -> gamma
eta_b(1S). This photon energy corresponds to an eta_b(1S) mass of $9388.9
{+3.1} {-2.3} (stat) +/- 2.7(syst) MeV/c2. The hyperfine Upsilon(1S)-eta_b(1S)
mass splitting is 71.4 {+2.3} {-3.1} (stat) +/- 2.7(syst) MeV/c2. The branching
fraction for this radiative Upsilon(3S) decay is estimated to be (4.8 +/-
0.5(stat) +/- 1.2 (syst)) x 10^(-4).


title: Controlling the propagation of light in disordered scattering media

abstract:
  This thesis describes experimental work on the use of wavefront shaping to
steer light through strongly scattering materials. We find that scattering does
not irreversibly scramble the incident wave. By shaping the incident wavefront,
we make opaque objects focus light as sharply as aberration free lenses. We use
feedback from a target behind, or in, an opaque object to shape the incident
wave. This way, light is focused through, or inside, opaque objects for the
first time ever.


title: The Pioneer Anomaly

abstract:
  Analysis of the radio-metric data from Pioneer 10 and 11 spacecrafts has
indicated the presence of an unmodeled acceleration starting at 20 AU, which
has become known as the Pioneer anomaly. The nature of this acceleration is
uncertain. In this paper we give a description of the effect and review some
relevant mechanisms proposed to explain the observed anomaly. We also discuss
on some future projects to investigate this phenomenon.


title:
Effect of pressure on the structural phase transition and
  superconductivity in (Ba$_{1-x}$K$_x$)Fe$_2$As$_2$ ($x = 0$ and 0.45) single
  crystals

abstract:
  The effects of pressure up to $\sim 20$ kbar, on the structural phase
transition of lightly Sn-doped BaFe$_2$As$_2$, as well as on the
superconducting transition temperature and upper critical field of
(Ba$_{0.55}$K$_{0.45}$)Fe$_2$As$_2$ single crystals have been studied. Both
transitions decrease with pressure in an almost linear fashion. Under pressure,
the upper critical field curve, $H_{c2}(T)$, shifts down in temperature to
follow the zero field $T_c$ with very little change in slope.


title: Non-enlargeable operators and self-cancelling operators

abstract:
  The epsilon-enlargement of a maximal monotone operator is a construct similar
to the Br{\o}ndsted and Rocakfellar epsilon-subdifferential enlargement of the
subdifferential. Like the epsilon-subdifferential, the epsilon-enlargement of a
maximal monotone operator has practical and theoretical applications.
  In a recent paper in Journal of Convex Analysis Burachik and Iusem studied
conditions under which a maximal monotone operator is non-enlargeable, that is,
its epsilon-enlargement coincides with the operator. Burachik and Iusem studied
these non-enlargeable operators in reflexive Banach spaces, assuming the
interior of the domain of the operator to be nonempty. In the present work, we
remove the assumption on the domain of non-enlargeable operators and also
present partial results for the non-reflexive case.


title: Quasar Host Galaxies in the FORS Deep Field

abstract:
  (abriged)In this paper we study different properties of quasars and their
host galaxies at high redshifts up to z~3.4. We compare our results to those of
other authors and discuss the correlation between galaxy evolution and quasar
activity. We analysed broad-band images in eight filters (from U to K) of eight
quasars in the FORS Deep Field with redshifts between z=0.87 and z=3.37. A
fully 2-dimensional decomposition was carried out to detect and resolve the
host galaxies. We were able to resolve the host galaxies of two out of eight
quasars between z=0.87 and z=2.75. Additionally, two host galaxies were
possibly resolved. The resolved low-redshift quasar (z=0.9) was identified as a
late type galaxy with a moderate star formation rate of 1.8 M_{sun}/yr hosting
a supermassive black hole with a mass of <10^{8}M_{sun}. The resolved high
redshift host galaxy (z=2.8) shows moderate star formation of 4.4-6.9
M_{sun}/yr, for the black hole mass we found a lower limit of >10^{7}M_{sun}.
All quasars host supermassive black hole with masses in the range
~10^{7}-10^{9}M_{sun}. Our findings are well consistent with those of other
authors.


title: Search for Cosmic Axions using an Optical Interferometer

abstract:
  A high finesse optical cavity can be used to search for cosmic axions in the
mass range 10^{-6}< m_a <10^{-4} eV. Either a two-arm or a single-arm cavity is
suitable and in either case the signal as resonant sidebands imposed on the
carrier. Assuming for the local axion density the usual figure of 500 MeV/cm^3
[8], the KSVZ axion line [4] g/m_a = 0.4 Gev^{-2}, can be reached over the full
mass range in a one year search.


title: Decoherence and Entropy Production in Relativistic Nuclear Collisions

abstract:
  Short thermalization times of less than 1 fm/c for quark and gluon matter
have been suggested by recent experiments at the Relativistic Heavy Ion
Collider (RHIC). It has been difficult to justify this rapid thermalization in
first-principle calculations based on perturbation theory or the color glass
condensate picture. Here, we address the related question of the decoherence of
the gluon field, which is a necessary component of thermalization. We present a
simplified leading-order computation of the decoherence time of a gluon
ensemble subject to an incoming flux of Weizsacker-Williams gluons. We also
discuss the entropy produced during the decoherence process and its relation to
the entropy in the final state which has been measured experimentally.


title:
Probing superconducting energy gap from infrared spectroscopy on a
  Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ single crystal with T$_c$=37 K

abstract:
  We performed optical spectroscopy measurement on a superconducting
Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ single crystal with T$_c$=37 K. Formation of
the superconducting energy gaps in the far-infared reflectance spectra below
T$_c$ is clearly observed. The gap amplitudes match well with the two distinct
superconducting gaps observed in angle-resolved photoemission spectroscopy
experiments on different Fermi surfaces. We determined absolute value of the
penetration depth at 10 K as $\lambda\simeq2000 \AA$. A spectral weight
analysis shows that the Ferrell-Glover-Timkham sum rule is satisfied at low
energy scale, less than 6$\Delta$.


title:
Dual superconformal symmetry of scattering amplitudes in N=4
  super-Yang-Mills theory

abstract:
  We argue that the scattering amplitudes in the maximally supersymmetric N=4
super-Yang-Mills theory possess a new symmetry which extends the previously
discovered dual conformal symmetry. To reveal this property we formulate the
scattering amplitudes as functions in the appropriate dual superspace.
Rewritten in this form, all tree-level MHV and next-to-MHV amplitudes exhibit
manifest dual superconformal symmetry. We propose a new, compact and Lorentz
covariant formula for the tree-level NMHV amplitudes for arbitrary numbers and
types of external particles. The dual conformal symmetry is broken at loop
level by infrared divergences. However, we provide evidence that the anomalous
contribution to the MHV and NMHV superamplitudes is the same and, therefore,
their ratio is a dual conformal invariant function. We identify this function
by an explicit calculation of the six-particle amplitudes at one loop. We
conjecture that these properties hold for all, MHV and non-MHV, superamplitudes
in N=4 SYM both at weak and at strong coupling.


title: Electric Dipole Moments in U(1)' Models

abstract:
  We study electric dipole moments (EDM) of electron and proton in
E(6)--inspired supersymmetric models with an extra U(1) invariance. Compared to
the Minimal Supersymmetric Standard Model (MSSM), in addition to offering a
natural solution to the mu problem and predicting a larger mass for the
lightest Higgs boson, these models are found to yield suppressed EDMs.


title: Probing Electron-Capture Supernovae: X-Ray Binaries in Starbursts

abstract:
  Presenting population models of high-mass X-ray binaries (HMXBs) formed after
bursts of star formation, we investigate the effect of electron-capture
supernovae (ECS) of massive ONeMg white dwarfs and the hypothesis that ECS
events are associated with typically low supernova kicks imparted to the
nascent neutron stars. We identify an interesting ECS bump in the time
evolution of HMXB numbers; this bump is caused by significantly increased
production of wind-fed HMXBs 20-60 Myr post starburst. The amplitude and age
extent of the ECS bump depend on the strength of ECS kicks and the mass range
of ECS progenitors. We also find that ECS-HMXBs form through a specific
evolutionary channel that is expected to lead to binaries with Be donors in
wide orbits. These characteristics, along with their sensitivity to ECS
properties, provide us with an intriguing opportunity to probe ECS physics and
progenitors through studies of starbursts of different ages. Specifically, the
case of the Small Magellanic Cloud, with a significant observed population of
Be HMXBs and starburst activity 30-60 Myr ago, arises as a promising laboratory
for understanding the role of electron-capture supernovae in neutron star
formation.


title:
A New View of the Super Star Clusters in the Low-Metallicity Galaxy SBS
  0335-052

abstract:
  We present a study of the individual super star clusters (SSCs) in the
low-metallicity galaxy SBS 0335-052 using new near-infrared and archival
optical Hubble Space Telescope observations. The physical properties of the
SSCs are derived from fitting model spectral energy distributions (SEDs) to the
optical photometry, as well as from the H_alpha and Pa_alpha nebular emission.
Among the clusters, we find a significant age spread that is correlated with
position in the galaxy, suggesting successive cluster formation occurred in SBS
0335-052 triggered by a large-scale disturbance traveling through the galaxy at
a speed of ~35 km/s. The SSCs exhibit I-band (~0.8 um) and near-IR (~1.6-2.1
um) excesses with respect to model SEDs fit to the optical data. We hypothesize
that the I-band excess is dominated by a photoluminescent process known as
Extended Red Emission; however, this mechanism cannot account for the excesses
observed at longer near-IR wavelengths. From the cluster SEDs and colors, we
find that the primary origin of the near-IR excess observed in the youngest
SSCs (<3 Myr) is hot dust emission, while evolved red supergiants dominate the
near-IR light in the older (>7 Myr) clusters. We also find evidence for a
porous and clumpy interstellar medium (ISM) surrounding the youngest, embedded
SSCs: the ionized gas emission underpredicts the expected ionizing luminosities
from the optical stellar continuum, suggesting ionizing photons are leaking out
of the immediate vicinity of the clusters before ionizing hydrogen. The
corrected, intrinsic ionizing luminosities of the two SSCs younger than ~3 Myr
are each ~ 5x10^52 s^-1, which is equivalent to each cluster hosting ~5000 O7.5
V stars. The inferred masses of these SSCs are ~10^6 M_sun.


title: Heating up Galilean holography

abstract:
  We embed a holographic description of a quantum field theory with Galilean
conformal invariance in string theory. The key observation is that such field
theories may be realized as conventional superconformal field theories with a
known string theory embedding, twisted by the R-symmetry in a light-like
direction. Using the Null Melvin Twist, we construct the appropriate dual
geometry and its non-extremal generalization. From the nonzero temperature
solution we determine the equation of state. We also discuss the hydrodynamic
regime of these non-relativistic plasmas and show that the shear viscosity to
entropy density ratio takes the universal value one over four pi typical of
strongly interacting field theories with gravity duals.


title:
Comments on string theory backgrounds with non-relativistic conformal
  symmetry

abstract:
  We consider non-relativistic conformal quantum mechanical theories that arise
by doing discrete light cone quantization of field theories. If the field
theory has a gravity dual, then the conformal quantum mechanical theory can
have a gravity dual description in a suitable finite temperature and finite
density regime. Using this we compute the thermodynamic properties of the
system. We give an explicit example where we display both the conformal quantum
mechanical theory as well as the gravity dual. We also discuss the string
theory embedding of certain backgrounds with non-relativistic conformal
symmetry that were recently discussed. Using this, we construct finite
temperature and finite density solutions, with asymptotic non-relativistic
conformal symmetry. In addition, we derive consistent Kaluza-Klein truncations
of type IIB supergravity to a five dimensional theory with massive vector
fields.


title: Conditions for large non-Gaussianity in two-field slow-roll inflation

abstract:
  We study the level of primordial non-Gaussianity in slow-roll two-field
inflation. Using an analytic formula for the nonlinear parameter f_nl in the
case of a sum or product separable potential, we find that it is possible to
generate significant non-Gaussianity even during slow-roll inflation with
Gaussian perturbations at Hubble exit. In this paper we give the general
conditions to obtain large non-Gaussianity and calculate the level of
fine-tuning required to obtain this. We present explicit models in which the
non-Gaussianity at the end of inflation can exceed the current observational
bound of |f_nl|<100.


title: Classification of N=6 superconformal theories of ABJM type

abstract:
  Studying the supersymmetry enhancement mechanism of Aharony, Bergman,
Jafferis and Maldacena, we find a simple condition on the gauge group
generators for the matter fields. We analyze all possible compact Lie groups
and their representations. The only allowed gauge groups leading to the
manifest N=6 supersymmetry are, up to discrete quotients, SU(n) x U(1), Sp(n) x
U(1), SU(n) x SU(n), and SU(n) x SU(m) x U(1) with possibly additional U(1)'s.
Matter representations are restricted to be the (bi)fundamentals. As a
byproduct we obtain another proof of the complete classification of the three
algebras considered by Bagger and Lambert.


title: Globular Clusters in the Outer Galactic Halo: AM-1 and Palomar 14

abstract:
  AM-1, at ~120 kpc, and Pal 14, at ~70 kpc, are two of the most distant
Galactic globular clusters known. We present Hubble Space Telescope WFPC2
photometry of AM-1 and Pal 14 that reveals unprecedented depth and detail in
the color-magnitude diagrams of these two clusters. Absolute and relative age
measurements confirm that both are younger than the inner halo globular cluster
M 3 by 1.5-2 Gyr, assuming all three clusters have similar compositions. Thus
AM-1 and Pal 14 join Pal 3, Pal 4, and Eridanus (studied by Stetson et al.) as
distant Galactic globular clusters with red horizontal branches and young ages
relative to the inner halo. Within the context of the entire body of research
on the ages of second parameter globular clusters, the observed correlation
between age and horizontal branch morphology suggests that age is the best
candidate for the second parameter. However, this conclusion is tempered by the
lack of precise chemical abundance determinations for a significant fraction of
second parameter globular clusters.


title: Evidence for a bound on the lifetime of de Sitter space

abstract:
  Recent work has suggested a surprising new upper bound on the lifetime of de
Sitter vacua in string theory. The bound is parametrically longer than the
Hubble time but parametrically shorter than the recurrence time. We investigate
whether the bound is satisfied in a particular class of de Sitter solutions,
the KKLT vacua. Despite the freedom to make the supersymmetry breaking scale
exponentially small, which naively would lead to extremely stable vacua, we
find that the lifetime is always less than about exp(10^(22)) Hubble times, in
agreement with the proposed bound.


title: Induced Kozai Migration and Formation of Close-in Planets in Binaries

abstract:
  Many recent observational studies have concluded that planetary systems
commonly exist in multiple-star systems. At least ~20%, and presumably a larger
fraction of the known extrasolar planetary systems are associated with one or
more stellar companions. These stellar companions normally exist at large
distances from the planetary systems (typical projected binary separations are
on the orders 100-10000AU) and are often faint (ranging from F to T spectral
types). Yet, secular cyclic angular momentum exchange with these distant
stellar companions can significantly alter the orbital configuration of the
planets around the primaries. One of the most interesting and fairly common
outcomes seen in numerical simulations is the opening of a large mutual
inclination angle between the planetary orbits, forced by differential nodal
precessions caused by the binary companion. The growth of the mutual
inclination angle between planetary orbits induces additional large-amplitude
eccentricity oscillations of the inner planet due to the quadrupole
gravitational perturbation by the outer planet. This eccentricity oscillation
may eventually result in the orbital decay of the inner planet through tidal
friction, as previously proposed as Kozai migration or Kozai cycles with tidal
friction (KCTF). This orbital decay mechanism induced by the binary
perturbation and subsequent tidal dissipation may stand as an alternative
formation channel for close-in extrasolar planets.


title:
Principal components analysis for sparsely observed correlated
  functional data using a kernel smoothing approach

abstract:
  In this paper, we consider the problem of estimating the covariance kernel
and its eigenvalues and eigenfunctions from sparse, irregularly observed, noise
corrupted and (possibly) correlated functional data. We present a method based
on pre-smoothing of individual sample curves through an appropriate kernel. We
show that the naive empirical covariance of the pre-smoothed sample curves
gives highly biased estimator of the covariance kernel along its diagonal. We
attend to this problem by estimating the diagonal and off-diagonal parts of the
covariance kernel separately. We then present a practical and efficient method
for choosing the bandwidth for the kernel by using an approximation to the
leave-one-curve-out cross validation score. We prove that under standard
regularity conditions on the covariance kernel and assuming i.i.d. samples, the
risk of our estimator, under $L^2$ loss, achieves the optimal nonparametric
rate when the number of measurements per curve is bounded. We also show that
even when the sample curves are correlated in such a way that the noiseless
data has a separable covariance structure, the proposed method is still
consistent and we quantify the role of this correlation in the risk of the
estimator.


title:
Five-Branes in M-Theory and a Two-Dimensional Geometric Langlands
  Duality

abstract:
  A recent attempt to extend the geometric Langlands duality to affine
Kac-Moody groups, has led Braverman and Finkelberg [arXiv:0711.2083] to
conjecture a mathematical relation between the intersection cohomology of the
moduli space of G-bundles on certain singular complex surfaces, and the
integrable representations of the Langlands dual of an associated affine
G-algebra, where G is any simply-connected semisimple group. For the A-type
groups, where the conjecture has been mathematically verified to a large
extent, we show that the relation has a natural physical interpretation in
terms of six-dimensional compactifications of M-theory with coincident
five-branes wrapping certain hyperkahler four-manifolds; in particular, it can
be understood as an expected invariance in the resulting spacetime BPS spectrum
under string dualities. By replacing the singular complex surface with a smooth
multi-Taub-NUT manifold, we find agreement with a closely related result
demonstrated earlier via purely field-theoretic considerations by Witten. By
adding OM five-planes to the original analysis, we argue that an analogous
relation involving the non-simply-connected D-type groups, ought to hold as
well. This is the first example of a string-theoretic interpretation of such a
two-dimensional extension to complex surfaces of the geometric Langlands
duality for the A-D groups.


title: Looking Beyond Lambda with the Union Supernova Compilation

abstract:
  The recent robust and homogeneous analysis of the world's supernova
distance-redshift data, together with cosmic microwave background and baryon
acoustic oscillation data, provides a powerful tool for constraining
cosmological models. Here we examine particular classes of scalar field,
modified gravity, and phenomenological models to assess whether they are
consistent with observations even when their behavior deviates from the
cosmological constant Lambda. Some models have tension with the data, while
others survive only by approaching the cosmological constant, and a couple are
statistically favored over LCDM. Dark energy described by two equation of state
parameters has considerable phase space to avoid Lambda and next generation
data will be required to constrain such physics.


title:
The Galaxy and its stellar halo - insights from a hybrid cosmological
  approach

abstract:
  We use a series of high-resolution N-body simulations of a `Milky-Way' halo,
coupled to semi-analytic techniques, to study the formation of our own Galaxy
and of its stellar halo. Our model Milky Way galaxy is a relatively young
system whose physical properties are in quite good agreement with observational
determinations. In our model, the stellar halo is mainly formed from a few
massive satellites accreted early on during the galaxy's lifetime. The stars in
the halo do not exhibit any metallicity gradient, but higher metallicity stars
are more centrally concentrated than stars with lower abundances. This is due
to the fact that the most massive satellites contributing to the stellar halo
are also more metal rich, and dynamical friction drags them closer to the inner
regions of the host halo.