title: Canonical measures and the dynamical systems of Bergman kernels

abstract:
  In this article, we construct the canonical semipositive current or the
canonical measure ($=$ the potential of the canonical semipositive current) on
a smooth projective variety of nonnegative Kodaira dimension in terms of a
dynamical system of Bergman kernels. This current is considered to be a
generalization of a K\"{a}hler-Einstein metric and coincides the one
constructed independently by J. Song and G. Tian. The major difference between
their work and the present article is that they found the canonical measure in
terms of K\"{a}her-Ricci flows, while I found the canonical measure in terms of
the dynamical system of Bergman kernels. Hence the present approach can be
viewed as the discrete version of the K\"{a}hler-Ricci flow.


title: Temperature dependent transport in suspended graphene

abstract:
  The resistivity of ultra-clean suspended graphene is strongly temperature
dependent for 5K<T<240K. At T~5K transport is near-ballistic in a device of
~2um dimension and a mobility ~170,000 cm^2/Vs. At large carrier density,
n>0.5*10^11 cm^-2, the resistivity increases with increasing T and is linear
above 50K, suggesting carrier scattering from acoustic phonons. At T=240K the
mobility is ~120,000 cm^2/Vs, higher than in any known semiconductor. At the
charge neutral point we observe a non-universal conductivity that decreases
with decreasing T, consistent with a density inhomogeneity <10^8 cm^-2.


title: Sub-Rayleigh Quantum Imaging Using Single Photon Sources

abstract:
  We propose a technique capable of imaging a distinct physical object with
sub-Rayleigh resolution in an ordinary far-field imaging setup using
single-photon sources and linear optical tools only. We exemplify our method
for the case of a rectangular aperture and two or four single-photon emitters
obtaining a resolution enhanced by a factor of two or four, respectively.


title: Bosonic amplification of noise-induced suppression of phase diffusion

abstract:
  We study the effect of noise-induced dephasing on collisional phase-diffusion
in the two-site Bose-Hubbard model. Dephasing of the quasi-momentum modes may
slow down phase-diffusion in the quantum Zeno limit. Remarkably, the degree of
suppression is enhanced by a bosonic factor of order $N/\log{N}$ as the
particle number $N$ increases.


title: Complex structures on quasi-filiform nilpotent Lie algebras

abstract:
  We present the classification of real nilpotent quasi-filiform Lie algebras
endowed with a complex structure. A nilpotent Lie algebra g is called
quasi-filiform is the nilindex is equal to dim(n)-2. We recall that the
filiform case (nilindex =dim(g)-1) has already been studied.


title: Maximal symmetry and metric-affine f(R) gravity

abstract:
  The affine connection in a space-time with a maximally symmetric spatial
subspace is derived using the properties of maximally symmetric tensors. The
number of degrees of freedom in metric-affine gravity is thereby considerably
reduced while the theory allows spatio-temporal torsion and remains non-metric.
The Ricci tensor and scalar are calculated in terms of the connection and the
field equations derived for the Einstein-Hilbert as wells as for f(R)
Lagrangians. By considering specific forms of f(R), we demonstrate that the
resulting Friedmann equations in Palatini formalism without torsion and
metric-affine formalism with maximal symmetry are in general different in the
presence of matter.


title:
Effects of the (rho, omega, phi) mixing on the dipion mass spectrum in
  e+ e- annihilation and tau decay

abstract:
  A way to explain the puzzling difference between the pion form factor as
measured in e+ e- annihilations and in tau decays is discussed. We show that
isospin symmetry breaking, beside the already identified effects, produces also
a full mixing between the rho0, omega and phi mesons which generates an isospin
0 component inside the rho0 meson. This effect, not accounted for in current
treatments of the problem, seems able to account for the apparent mismatch
between e+ e- and tau data below the phi mass.


title: Coupled Dynamics on Networks

abstract:
  We study the synchronization of coupled dynamical systems on a variety of
networks. The dynamics is governed by a local nonlinear map or flow for each
node of the network and couplings connecting different nodes via the links of
the network. For small coupling strengths nodes show turbulent behavior but
form synchronized clusters as coupling increases. When nodes show synchronized
behaviour, we observe two interesting phenomena. First, there are some nodes of
the floating type that show intermittent behaviour between getting attached to
some clusters and evolving independently. Secondly, we identify two different
ways of cluster formation, namely self-organized clusters which have mostly
intra-cluster couplings and driven clusters which have mostly inter-cluster
couplings.


title:
Symbolic dynamics and synchronization of coupled map networks with
  multiple delays

abstract:
  We use symbolic dynamics to study discrete-time dynamical systems with
multiple time delays. We exploit the concept of avoiding sets, which arise from
specific non-generating partitions of the phase space and restrict the
occurrence of certain symbol sequences related to the characteristics of the
dynamics. In particular, we show that the resulting forbidden sequences are
closely related to the time delays in the system. We present two applications
to coupled map lattices, namely (1) detecting synchronization and (2)
determining unknown values of the transmission delays in networks with possibly
directed and weighted connections and measurement noise. The method is
applicable to multi-dimensional as well as set-valued maps, and to networks
with time-varying delays and connection structure.


title: Fractional Levy motion through path integrals

abstract:
  Fractional Levy motion (fLm) is the natural generalization of fractional
Brownian motion in the context of self-similar stochastic processes and stable
probability distributions. In this paper we give an explicit derivation of the
propagator of fLm by using path integral methods. The propagators of Brownian
motion and fractional Brownian motion are recovered as particular cases. The
fractional diffusion equation corresponding to fLm is also obtained.


title: Instability of frozen-in states in synchronous Hebbian neural networks

abstract:
  The full dynamics of a synchronous recurrent neural network model with Ising
binary units and a Hebbian learning rule with a finite self-interaction is
studied in order to determine the stability to synaptic and stochastic noise of
frozen-in states that appear in the absence of both kinds of noise. Both, the
numerical simulation procedure of Eissfeller and Opper and a new alternative
procedure that allows to follow the dynamics over larger time scales have been
used in this work. It is shown that synaptic noise destabilizes the frozen-in
states and yields either retrieval or paramagnetic states for not too large
stochastic noise. The indications are that the same results may follow in the
absence of synaptic noise, for low stochastic noise.


title: Effective Field Theory with a Variable Ultraviolet Cutoff

abstract:
  The properties of strongly gravitating systems suggest that field theory
overcounts the states of a system. Reducing the number of degrees of freedom,
without abandoning the notion of effective field theory, may be achieved
through a connection between the ultraviolet and infrared cutoffs. We provide
an implementation of this idea within the Wilsonian approach to the
renormalization group. We derive an exact flow equation that describes the
evolution of the effective action. We discuss the implications for the
existence of infrared fixed points and the running of couplings. We also give
an alternative derivation in the context of the perturbative renormalization
group.


title:
The extragalactic optical-infrared background radiations, their time
  evolution and the cosmic photon-photon opacity

abstract:
  The background radiations in the optical and the infrared constitute a
relevant cause of energy loss in the propagation of high energy particles
through space. In particular, TeV observations with Cherenkov telescopes of
extragalactic sources are influenced by the opacity effects due to the
interaction of the very high-energy source photons with the background light.
With the aim of assessing with the best possible detail these opacity terms, we
have modelled the extragalactic optical and IR backgrounds using available
information on cosmic sources in the universe from far-UV to sub-mm wavelengths
over a wide range of cosmic epochs. We have exploited the relevant cosmological
survey data - including number counts, redshift distributions, luminosity
functions - from ground-based observatories in the optical, near-IR, and
sub-mm, as well as multi-wavelength information coming from space telescopes,
HST, ISO and Spitzer. Additional constraints have been used from direct
measurements or upper limits on the extragalactic backgrounds by dedicated
missions (COBE). All data were fitted and interpolated with a multi-wavelength
backward evolutionary model, allowing us to estimate the background photon
density and its redshift evolution. From the redshift-dependent background
spectrum, the photon-photon opacities for sources of high-energy emission at
any redshifts were then computed. The same results can also be used to compute
the optical depths for any kind of processes in the intergalactic space
involving interactions with background photons (like scattering of cosmic-ray
particles). We have applied our photon-photon opacity estimates to the analysis
of spectral data at TeV energies on a few BLAZARs of particular interest.
[abridged]


title: A finiteness theorem for dual graphs of surface singularities

abstract:
  Consider a fixed connected, finite graph $\Gamma$ and equip its vertices with
weights $p_i$ which are non-negative integers. We show that there is a finite
number of possibilities for the coefficients of the canonical cycle of a
numerically Gorenstein surface singularity having $\Gamma$ as the dual graph of
the minimal resolution, the weights $p_i$ of the vertices being the arithmetic
genera of the corresponding irreducible components. As a consequence we get
that if $\Gamma$ is not a cycle, then there is a finite number of possibilities
of self-intersection numbers which one can attach to the vertices which are of
valency $\geq 2$, such that one gets the dual graph of the minimal resolution
of a numerically Gorenstein surface singularity. Moreover, we describe
precisely the situations when there exists an infinite number of possibilities
for the self-intersections of the component corresponding to some fixed vertex
of $\Gamma$.


title: Stability and structure of atomic chains on Si(111)

abstract:
  We study the stability and structure of self-assembled atomic chains on
Si(111) induced by monovalent, divalent and trivalent adsorbates, using
first-principles total-energy calculations and scanning tunneling microscopy.
We find that only structures containing exclusively silicon honeycomb or
silicon Seiwatz chains are thermodynamically stable, while mixed
configurations, with both honeycomb and Seiwatz chains, may be kinetically
stable. The stability and structure of these atomic chains can be understood
using a surprisingly simple electron-counting rule.


title:
Practical recipes for the model order reduction, dynamical simulation,
  and compressive sampling of large-scale open quantum systems

abstract:
  This article presents numerical recipes for simulating high-temperature and
non-equilibrium quantum spin systems that are continuously measured and
controlled. The notion of a spin system is broadly conceived, in order to
encompass macroscopic test masses as the limiting case of large-j spins. The
simulation technique has three stages: first the deliberate introduction of
noise into the simulation, then the conversion of that noise into an equivalent
continuous measurement and control process, and finally, projection of the
trajectory onto a state-space manifold having reduced dimensionality and
possessing a Kahler potential of multi-linear form. The resulting simulation
formalism is used to construct a positive P-representation for the thermal
density matrix. Single-spin detection by magnetic resonance force microscopy
(MRFM) is simulated, and the data statistics are shown to be those of a random
telegraph signal with additive white noise. Larger-scale spin-dust models are
simulated, having no spatial symmetry and no spatial ordering; the
high-fidelity projection of numerically computed quantum trajectories onto
low-dimensionality Kahler state-space manifolds is demonstrated. The
reconstruction of quantum trajectories from sparse random projections is
demonstrated, the onset of Donoho-Stodden breakdown at the Candes-Tao sparsity
limit is observed, a deterministic construction for sampling matrices is given,
and methods for quantum state optimization by Dantzig selection are given.


title:
On the $L_{q,p}$-cohomology of Riemannian Manifolds with Negative
  Curvature

abstract:
  We prove a non-vanishing result for the $L_{q,p}$-cohomology of complete
simply-connected Riemannian manifolds with pinched negative curvature.


title: Center Vortices and the Dirac Spectrum

abstract:
  We study correlations between center vortices and the low-lying eigenmodes of
the Dirac operator, in both the overlap and asqtad formulations. In particular
we address a puzzle raised some years ago by Gattnar et al. [Nucl. Phys. B 716,
105 (2005)], who noted that the low-lying Dirac eigenmodes required for chiral
symmetry breaking do not appear to be present in center-projected
configurations. We show that the low-lying modes are in fact present in the
staggered (asqtad) formulation, but not in the overlap and ``chirally
improved'' formulations, and suggest a reason for this difference. We also
confirm and extend the results of Kovalenko et al. [Phys. Lett. B 648, 383
(2007)], showing that there is a correlation between center vortex locations,
and the scalar density of low-lying Dirac eigenmodes derived from unprojected
configurations. This correlation is strongest at points which are associated,
in the vortex picture, with non-vanishing topological charge density, such as
vortex intersection and ``writhing'' points. We present supporting evidence
that the lowest Dirac eigenmodes, in both asqtad and overlap formulations, have
their largest concentrations in point-like regions, rather than on submanifolds
of higher dimensionality.


title:
Coherent state quantization of angle, time, and more irregular functions
  and distributions

abstract:
  The domain of application of quantization methods is traditionally restricted
to smooth classical observables. We show that the coherent states or
"anti-Wick" quantization enables us to construct fairly reasonable quantum
versions of irregular observables living on the classical phase space, such as
the angle function, the time function of a free particle and even a large set
of distributions comprising the tempered distributions.


title:
On the Dynamics of Proto-Neutron Star Winds and r-Process
  Nucleosynthesis

abstract:
  We study here the formation of heavy r-process nuclei in the high-entropy
environment of rapidly expanding neutrino-driven winds from compact objects. In
particular, we explore the sensitivity of the element creation in the A>130
region to the low-temperature behavior of the outflows. For this purpose we
employ a simplified model of the dynamics and thermodynamical evolution for
radiation dominated, adiabatic outflows. It consists of a first stage of fast,
exponential cooling, followed by a second phase of slower evolution, either
assuming constant density and temperature or a power-law decay of these
quantities. These cases are supposed to capture the most relevant effects of a
strong deceleration or decreasing acceleration of the transsonic outflows,
respectively, e.g. in a wind termination shock caused by the collision with the
slower, preceding supernova ejecta. We find that not only the transition
temperature between the two expansion phases can make a big difference in the
formation of the platinum peak, but also the detailed cooling law during the
later phase. Unless the transition temperature and corresponding (free neutron)
density become too small (T < 2*10^8 K), a lower temperature or faster
temperature decline during this phase allow for a stronger appearance of the
third abundance peak. Since the nuclear photodisintegration rates between
~2*10^8 K and ~10^9 K are more sensitive to the temperature than the n-capture
rates are to the free neutron density, a faster cooling in this temperature
regime shifts the r-process path closer to the n-drip line. With low (gamma,n)-
but high beta-decay rates, the r-processing then does not proceed through a
(gamma,n)-(n,gamma) equilibrium but through a quasi-equilibrium of
(n,gamma)-reactions and beta-decays, as recently also pointed out by Wanajo.


title:
Are There Magnetars in High Mass X-ray Binaries? The Case of SuperGiant
  Fast X-Ray Transients

abstract:
  In this paper we survey the theory of wind accretion in high mass X-ray
binaries hosting a magnetic neutron star and a supergiant companion.
  We concentrate on the different types of interaction between the inflowing
wind matter and the neutron star magnetosphere that are relevant when accretion
of matter onto the neutron star surface is largely inhibited; these include the
inhibition through the centrifugal and magnetic barriers. Expanding on earlier
work, we calculate the expected luminosity for each regime and derive the
conditions under which transition from one regime to another can take place. We
show that very large luminosity swings (~10^4 or more on time scales as short
as hours) can result from transitions across different regimes.
  The activity displayed by supergiant fast X-ray transients, a recently
discovered class of high mass X-ray binaries in our galaxy, has often been
interpreted in terms of direct accretion onto a neutron star immersed in an
extremely clumpy stellar wind. We show here that the transitions across the
magnetic and/or centrifugal barriers can explain the variability properties of
these sources as a results of relatively modest variations in the stellar wind
velocity and/or density. According to this interpretation we expect that
supergiant fast X-ray transients which display very large luminosity swings and
host a slowly spinning neutron star are characterized by magnetar-like fields,
irrespective of whether the magnetic or the centrifugal barrier applies.
  Supergiant fast X-ray transients might thus provide a new opportunity to
detect and study magnetars in binary systems.


title:
Nature and distribution of iron sites in a sodium silicate glass
  investigated by neutron diffraction and EPSR simulation

abstract:
  The short and medium range structure of a NaFeSi2O6 (NFS) glass has been
investigated by high-resolution neutron diffraction with Fe isotopic
substitution, combined with Empirical Potential Structure Refinement (EPSR)
simulations. The majority (~60%) of Fe is 4-coordinated ([4]Fe) and corresponds
only to ferric iron, Fe3+, with a distance d[4]Fe3+-O=1.87$\pm$0.01{\AA} . This
is at variance with the 3D-structure predicted by glass stoichiometry. The
existence of a majority of [4]Fe3+ sites illustrates a glass structure that
differs from the structure of crystalline NaFeSi2O6, which contains only
octahedral Fe3+. The EPSR modeling of glass structure shows that [4]Fe3+ is
randomly distributed in the silicate network and shares corner with silicate
tetrahedra. The existence of a majority of [4]Fe3+ sites differs from the
structure of the corresponding crystalline phase, which contains only
octahedral Fe3+. The network-forming behavior of [4]Fe3+, coupled with the
presence of Na+ ions acting as charge-compensators, is at the origin of
peculiar physical properties of Fe-bearing glasses, such as the increase of the
elastic modulus of sodium silicate glasses with increasing Fe-concentration.
Our data provide also direct evidence for 5-coordinated Fe, with an average
distance d[5]Fe-O=2.01$\pm$0.01{\AA}. This second Fe population concerns both
Fe2+ and Fe3+. 5-coordinated Fe atoms tend to segregate by sharing mainly
edges. The direct structural evidence of the dual role of ferric iron in NFS
glass provides support for understanding the peculiar properties of NFS glass,
such as magnetic, optical, electronic or thermodynamic properties.


title: Lorentz Symmetry Violation and Galactic Magnetism

abstract:
  We analyze the generation of primordial magnetic fields during de Sitter
inflation in a Lorentz-violating theory of Electrodynamics containing a
Chern-Simons term which couples the photon to an external four-vector. We find
that, for appropriate magnitude of the four-vector, the generated field is
maximally helical and, through an inverse cascade caused by turbulence of
primeval plasma, reaches at the time of protogalactic collapse an intensity and
correlation length such as to directly explain galactic magnetism.


title:
Time dependent current in a nonstationary environment: A microscopic
  approach

abstract:
  Based on a microscopic system reservoir model,where the associated bath is
not in thermal equilibrium, we simulate the nonstationary Langevin dynamics and
obtained the generalized nonstationary fluctuation dissipation relation (FDR)
which asymptotically reduces to the traditional form. Our Langevin dynamics
incorporates non-Markovian process also, the origin of which lies on the
decaying term of the nonstationary FDR. We then follow the stochastic dynamics
of the Langevin particle based on the Fokker-Planck-Smoluchowski description,
in ratchet potential to obtain the steady and time dependent current in an
analytic form. We also examine the influence of initial excitation and
subsequent relaxation of bath modes on the transport of the Langevin particle
to show that the nonequilibrium nature of the bath leads to both strong
non-exponential dynamics as well as nonstationary current.


title:
Intermediate range order in (Fe,Al) silicate network glasses: a neutron
  diffraction and EPSR modeling investigation

abstract:
  The local structural environment and the spatial distribution of iron and
aluminum ions in sodosilicate glasses with composition NaFexAl1-xSi2O6 (x = 1,
0.8, 0.5 and 0) is studied by high-resolution neutron diffraction combined with
structural modeling using the Empirical Potential Structure Refinement (EPSR)
code. This work gives evidence of differences in the structural behavior of
Al3+ and Fe3+, which are both often considered to act as network formers in
charge-balanced compositions. The short-range environment and the structural
role of the two cations are not composition dependent, and hence the structure
of intermediate glasses can then be seen as a mixture of the structures of the
two end-members. All Al3+ is 4-coordinated for a distance
d[4]Al3+-O=1.76$\pm$0.01{\AA}. The high-resolution neutron data allows
deciphering between two populations of Fe. The majority of Fe3+ is
4-coordinated (d[4]Fe3+-O=1.87$\pm$0.01{\AA}) while the remaining Fe3+ and all
Fe2+ (~12% of total Fe) are 5-coordinated (d[5]Fe-O=2.01$\pm$0.01{\AA}). Both
AlO4 and FeO4 are randomly distributed and connected with the silicate network
in which they share corners with SiO4 tetrahedra, in agreement with a
network-forming role of those species. On the contrary FeO5 tends to form
clusters and to share edges with each other. 5-coordinated Fe is interpreted as
network modifier and it turns out that, even if this coordination number is
rare in crystals, it is more common in glasses in which they can have a key
role on physical properties.


title: A New Algorithm for Interactive Structural Image Segmentation

abstract:
  This paper proposes a novel algorithm for the problem of structural image
segmentation through an interactive model-based approach. Interaction is
expressed in the model creation, which is done according to user traces drawn
over a given input image. Both model and input are then represented by means of
attributed relational graphs derived on the fly. Appearance features are taken
into account as object attributes and structural properties are expressed as
relational attributes. To cope with possible topological differences between
both graphs, a new structure called the deformation graph is introduced. The
segmentation process corresponds to finding a labelling of the input graph that
minimizes the deformations introduced in the model when it is updated with
input information. This approach has shown to be faster than other segmentation
methods, with competitive output quality. Therefore, the method solves the
problem of multiple label segmentation in an efficient way. Encouraging results
on both natural and target-specific color images, as well as examples showing
the reusability of the model, are presented and discussed.


title:
Technical report: Adaptivity and optimality of the monotone least
  squares estimator for four different models

abstract:
  In this paper we will consider the estimation of a monotone regression (or
density) function in a fixed point by the least squares (Grenander) estimator.
We will show that this estimator is fully adaptive, in the sense that the
attained rate is given by a functional relation using the underlying function
$f_0$, and not by some smoothness parameter, and that this rate is optimal when
considering the class of all monotone functions, in the sense that there exists
a sequence of alternative monotone functions $f_1$, such that no other
estimator can attain a better rate for both $f_0$ and $f_1$. We also show that
under mild conditions the estimator attains the same rate in $L^q$ sense, and
we give general conditions for which we can calculate a (non-standard) limiting
distribution for the estimator.


title:
Use of group theory and Clifford algebra in the study of generalized
  Dirac equation for particles with arbitrary spin

abstract:
  Using condition of relativistic invariance, group theory and Clifford algebra
the component Lorentz invariance generalized Dirac equation for a particle with
arbitrary mass and spin is suggested, where In the case of half-integral spin
particles, this equation is reduced to the sets of two-component independent
matrix equations. It is shown that the relativistic scalar and integral spin
particles are described by component equation.


title: The Gaussian Many-Help-One Distributed Source Coding Problem

abstract:
  Jointly Gaussian memoryless sources are observed at N distinct terminals. The
goal is to efficiently encode the observations in a distributed fashion so as
to enable reconstruction of any one of the observations, say the first one, at
the decoder subject to a quadratic fidelity criterion. Our main result is a
precise characterization of the rate-distortion region when the covariance
matrix of the sources satisfies a "tree-structure" condition. In this
situation, a natural analog-digital separation scheme optimally trades off the
distributed quantization rate tuples and the distortion in the reconstruction:
each encoder consists of a point-to-point Gaussian vector quantizer followed by
a Slepian-Wolf binning encoder. We also provide a partial converse that
suggests that the tree structure condition is fundamental.


title:
Spin asymmetry for the 16O(gamma,pi- p) reaction in the Delta(1232)
  region within an effective Lagrangian approach

abstract:
  The spin asymmetry of the photon in the exclusive A(gamma,pi N)A-1 reaction
is computed employing a recently developed fully relativistic model based on
elementary pion production amplitudes that include a consistent treatment of
the spin-3/2 nucleon resonances. We compare the results of this model to the
only available data on Oxygen [Phys. Rev. C 61 (2000) 054609] and find that,
contrary to other models, the predicted spin asymmetry compares well to the
available experimental data in the Delta(1232) region. Our results indicate
that no major medium modifications in the Delta(1232) properties are needed in
order to describe the measured spin asymmetries.


title: Constructing the Simplest Possible Phylogenetic Network from Triplets

abstract:
  A phylogenetic network is a directed acyclic graph that visualises an
evolutionary history containing so-called reticulations such as recombinations,
hybridisations or lateral gene transfers. Here we consider the construction of
a simplest possible phylogenetic network consistent with an input set T, where
T contains at least one phylogenetic tree on three leaves (a triplet) for each
combination of three taxa. To quantify the complexity of a network we consider
both the total number of reticulations and the number of reticulations per
biconnected component, called the level of the network. We give polynomial-time
algorithms for constructing a level-1 respectively a level-2 network that
contains a minimum number of reticulations and is consistent with T (if such a
network exists). In addition, we show that if T is precisely equal to the set
of triplets consistent with some network, then we can construct such a network
with smallest possible level in time O(|T|^(k+1)), if k is a fixed upper bound
on the level of the network.


title: Unconditional basic sequences in spaces of large density

abstract:
  We study the problem of the existence of unconditional basic sequences in
Banach spaces of high density. We show, in particular, the relative consistency
with GCH of the statement that every Banach space of density $\aleph_\omega$
contains an unconditional basic sequence.


title: Central Charge for 2D Gravity on AdS(2) and AdS(2)/CFT(1) Correspondence

abstract:
  We study 2D Maxwell-dilaton gravity on AdS(2). We distinguish two distinctive
cases depending on whether the AdS(2) solution can be lifted to an AdS(3)
geometry. In both cases, in order to get a consistent boundary condition we
need to work with a twisted energy momentum tensor which has non-zero central
charge. With this central charge and the explicit form of the twisted Virasoro
generators we compute the entropy of the system using the Cardy formula. The
entropy is found to be the same as that obtained from gravity calculations for
a specific value of the level of the U(1) current. The agreement is an
indication of $AdS(2)/CFT(1) correspondence.


title: On the nonradiating motion of point charges

abstract:
  We investigate the possible existence of nonradiating motions of systems of
point charges, according to classical electrodynamics with retarded potentials.
We prove that two point particles of arbitrary electric charges cannot move for
an infinitely long time within a finite region of space without radiating
electromagnetic energy. We show however with an example that nonradiating
accelerated motions of systems of point charges do in general exist.


title:
Cell contamination and branching process in random environment with
  immigration

abstract:
  We consider a branching model for a population of dividing cells infected by
parasites. Each cell receives parasites by inheritance from its mother cell and
independent contamination from outside the population. Parasites multiply
randomly inside the cell and are shared randomly between the two daughter cells
when the cell divides. The law of the number of parasites which contaminate a
given cell depends only on whether the cell is already infected or not. We
determine the asymptotic behavior of the number of parasites in a cell line,
which follows a branching process in random environment with state dependent
immigration. We then derive a law of large numbers for the asymptotic
proportions of cells with a given number of parasites. The main tools are
branching processes in random environment and laws of large numbers for Markov
tree.


title: Direct spectroscopic observations of clumping in O-star winds

abstract:
  We report the detection and monitoring of transient substructures in the
radiation-driven winds of five massive, hot stars in different evolutionary
stages. Clumping in the winds of these stars shows up as variable, narrow
subpeaks superposed on their wide, wind-broadened (optical) emission lines.
Similar patterns of emission-line profile variations are detected in the Of
stars zeta Puppis and HD93129A, in the more evolved hydrogen-rich, luminous,
Of-like WN stars HD93131 and HD93162, and in the more mass-depleted WC star in
gamma2 Velorum. These observations strongly suggest that stochastic wind
clumping is a universal phenomenon in the radiation-driven, hot winds from all
massive stars, with similar clumping factors in all stages of mass depletion.


title: A origami of genus 2 with a translation

abstract:
  We study an example of a Teichmueller curve in the moduli space of algebraic
curves of genus 2 coming from an origami S. It is particular in that its points
admit the Klein four group as a subgroup of the automorphism group. We give an
explicit description of its points in terms of affine plane curves, we show
that the Teichmueller curve is a nonsingular, affine curve of genus 0 and we
determine the number of cusps in the boundary of the moduli space.


title: Perfect transfer of m-qubit GHZ states

abstract:
  By using some techniques such as spectral distribution and stratification
associated with the graphs, employed in [1,2] for the purpose of Perfect state
transfer (PST) of a single qubit over antipodes of distance-regular spin
networks and PST of a $d$-level quantum state over antipodes of pseudo-distance
regular networks, PST of an m-qubit GHZ state is investigated. To do so, we
employ the particular distance-regular networks (called Johnson networks)
J(2m,m) to transfer an m-qubit GHZ state initially prepared in an arbitrary
node of the network (called the reference node) to the corresponding antipode,
perfectly.
  Keywords: Perfect state transferenc, GHZ states, Johnson network,
Stratification, Spectral distribution
  PACs Index: 01.55.+b, 02.10.Yn


title:
Superluminal problem in diffusion of relativistic particles and its
  phenomenological solution

abstract:
  We discuss the superluminal problem in the diffusion of ultra high energy
protons with energy losses taken into account. The phenomenological solution of
this problem is found with help of the generalized J\"uttner propagator,
originally proposed for relativization of the Maxwellian gas distribution. It
is demonstrated that the generalized J\"uttner propagator gives the correct
expressions in the limits of diffusive and rectilinear propagation of the
charged particles in the magnetic fields, together with the intermediate
regime, in all cases without superluminal velocities. This solution, very
general for the diffusion, is considered for two particular cases: diffusion
inside the stationary objects, like e.g. galaxies, clusters of galaxies etc,
and for expanding universe. The comparison with the previously obtained
solutions for propagation of UHE protons in magnetic fields is performed.


title:
On the applicability of bosonization and the Anderson-Yuval methods at
  the strong-coupling limit of quantum impurity problems

abstract:
  The applicability of bosonization and the Anderson-Yuval (AY) approach at
strong coupling is investigated by considering two generic impurity models: the
multichannel interacting resonant-level and the anisotropic Kondo models. The
two methods differ in the renormalization of the conduction-electron density of
states (DoS) near the impurity site. Reduction of the DoS, absent in
bosonization but accounted for in the AY approach, is shown to be vital in some
models yet redundant in others. The criterion being the stability of the
strong-coupling fixed point. Renormalization of the DoS is essential for an
unstable fixed point, but redundant when a decoupled entity with local dynamics
is formed. This rule can be used to boost the accuracy of both methods at
strong coupling.


title: Boundary conditions in local electrostatics algorithms

abstract:
  We study the simulation of charged systems in the presence of general
boundary conditions in a local Monte Carlo algorithm based on a constrained
electric field. We firstly show how to implement constant-potential, Dirichlet,
boundary conditions by introducing extra Monte Carlo moves to the algorithm.
Secondly, we show the interest of the algorithm for studying systems which
require anisotropic electrostatic boundary conditions for simulating planar
geometries such as membranes.


title:
Reference-less detection, astrometry, and photometry of faint companions
  with adaptive optics

abstract:
  We propose a complete framework for the detection, astrometry, and photometry
of faint companions from a sequence of adaptive optics corrected short
exposures. The algorithms exploit the difference in statistics between the
on-axis and off-axis intensity. Using moderate-Strehl ratio data obtained with
the natural guide star adaptive optics system on the Lick Observatory's 3-m
Shane Telescope, we compare these methods to the standard approach of PSF
fitting. We give detection limits for the Lick system, as well as a first guide
to expected accuracy of differential photometry and astrometry with the new
techniques. The proposed approach to detection offers a new way of determining
dynamic range, while the new algorithms for differential photometry and
astrometry yield accurate results for very faint and close-in companions where
PSF fitting fails. All three proposed algorithms are self-calibrating, i.e.
they do not require observation of a calibration star thus improving the
observing efficiency.


title:
Applying Mellin-Barnes technique and Groebner bases to the three-loop
  static potential

abstract:
  The Mellin-Barnes technique to evaluate master integrals and the algorithm
called FIRE to solve IBP relations with the help of Groebner bases are briefly
reviewed. In FIRE, an extension of the classical Buchberger algorithm to
construct Groebner bases is combined with the well-known Laporta algorithm. It
is explained how both techniques are used when evaluating the three-loop
correction to the static QCD quark potential. First results are presented: the
coefficients of n_l^3 and n_l^2, where n_l is the number of light quarks.


title:
Avoidance of Partially Ordered Generalized Patterns of the form
  $k$-$\sigma$-$k$

abstract:
  Sergey Kitaev has shown that the exponential generating function for
permutations avoiding the generalized pattern $\sigma$-$k$, where $\sigma$ is a
pattern without dashes and $k$ is one greater than the biggest element in
$\sigma$, is determined by the exponential generating function for permutations
avoiding $\sigma$.
  We show that this also holds for permutations avoiding all the generalized
patterns $\sigma_1$-$k_1$, $...$, $\sigma_n$-$k_n$, where $\sigma_1$, $...$,
$\sigma_n$ are patterns without dashes and $k_i$ is one greater than the
biggest element in $\sigma_i$. Similarly the exponential generating function
for permutations avoiding the partially ordered generalized patterns
$k_1$-$\sigma_1$-$k_1$, $...$, $k_n$-$\sigma_n$-$k_n$ can be determined from
the exponential generating function for permutations avoiding the generalized
patterns $\sigma_1$, $...$, $\sigma_n$, where $\sigma_1$, $...$, $\sigma_n$ are
patterns without dashes and $k_i$ is one greater than the largest element in
$\sigma_i$.
  Using this we construct a bijection between bicolored set partitions and
permutations avoiding the partially ordered generalized pattern 3-12-3 (that
is, permutations avoiding both the patterns 3-12-4 and 4-12-3). By using this
method twice, we find a closed formula for the exponential generating function
for permutations avoiding the partially ordered generalized pattern 3-121-3.
  Finally, we give a complete classification of when single partially ordered
generalized patterns have the same set of avoiders.


title: DARWIN - A Mission to Detect, and Search for Life on, Extrasolar Planets

abstract:
  The discovery of extra-solar planets is one of the greatest achievements of
modern astronomy. The detection of planets with a wide range of masses
demonstrates that extra-solar planets of low mass exist. In this paper we
describe a mission, called Darwin, whose primary goal is the search for, and
characterization of, terrestrial extrasolar planets and the search for life.
Accomplishing the mission objectives will require collaborative science across
disciplines including astrophysics, planetary sciences, chemistry and
microbiology. Darwin is designed to detect and perform spectroscopic analysis
of rocky planets similar to the Earth at mid-infrared wavelengths (6 - 20
micron), where an advantageous contrast ratio between star and planet occurs.
The baseline mission lasts 5 years and consists of approximately 200 individual
target stars. Among these, 25 to 50 planetary systems can be studied
spectroscopically, searching for gases such as CO2, H2O, CH4 and O3. Many of
the key technologies required for the construction of Darwin have already been
demonstrated and the remainder are estimated to be mature in the near future.
Darwin is a mission that will ignite intense interest in both the research
community and the wider public.


title: Two-Point Functions of Chiral Fields at One Loop in Type II

abstract:
  We compute the two-point functions for chiral matter states in toroidal
intersecting D6-brane models. In particular, we provide the techniques to
calculate Moebius strip diagrams including the worldsheet instanton
contribution.


title: The holomorphy conjecture for ideals in dimension two

abstract:
  The holomorphy conjecture predicts that the local Igusa zeta function
associated to a hypersurface and a character is holomorphic on $\mathbb{C}$
whenever the order of the character does not divide the order of any eigenvalue
of the local monodromy of the hypersurface. In this note we propose the
holomorphy conjecture for arbitrary subschemes at the level of the topological
zeta function and we prove this conjecture for subschemes defined by an ideal
that is generated by a finite number of complex polynomials in two variables.


title: Taking the Temperature of a Black Hole

abstract:
  We use the global embedding of a black hole spacetime into a higher
dimensional flat spacetime to define a local temperature for observers in free
fall outside a static black hole. The local free-fall temperature remains
finite at the event horizon and in asymptotically flat spacetime it approaches
the Hawking temperature at spatial infinity. Freely falling observers outside
an AdS black hole do not see any high-temperature thermal radiation even if the
Hawking temperature of such black holes can be arbitrarily high.


title: Perfect tag identification protocol in RFID networks

abstract:
  Radio Frequency IDentification (RFID) systems are becoming more and more
popular in the field of ubiquitous computing, in particular for objects
identification. An RFID system is composed by one or more readers and a number
of tags. One of the main issues in an RFID network is the fast and reliable
identification of all tags in the reader range. The reader issues some queries,
and tags properly answer. Then, the reader must identify the tags from such
answers. This is crucial for most applications. Since the transmission medium
is shared, the typical problem to be faced is a MAC-like one, i.e. to avoid or
limit the number of tags transmission collisions. We propose a protocol which,
under some assumptions about transmission techniques, always achieves a 100%
perfomance. It is based on a proper recursive splitting of the concurrent tags
sets, until all tags have been identified. The other approaches present in
literature have performances of about 42% in the average at most. The
counterpart is a more sophisticated hardware to be deployed in the manufacture
of low cost tags.


title:
Poles of the topological zeta function for plane curves and Newton
  polyhedra

abstract:
  The local topological zeta function is a rational function associated to a
germ of a complex holomorphic function. This function can be computed from an
embedded resolution of singularities of the germ. For nondegenerate functions
it is also possible to compute it from the Newton polyhedron. Both ways give
rise to a set of candidate poles of the topological zeta function, containing
all poles. For plane curves, Veys showed how to filter the actual poles out of
the candidate poles induced by the resolution graph. In this note we show how
to determine from the Newton polyhedron of a nondegenerate plane curve which
candidate poles are actual poles.


title:
Influence of the polarization in grazing scattering of fast hellium
  atoms from LiF(001) surfaces

abstract:
  Grazing scattering of neutral atoms from insulator surfaces is investigated
in the intermediate velocity range, in which interference effects have been
recently observed. To describe this process we introduce a distorted-wave
method, based on the use of the eikonal wave function, which takes into account
the phase of the scattering state along the classical projectile path. The
eikonal theory is applied to evaluate the angular distribution of few keV
helium atoms after impinging on a LiF(001) surface along low-index
crystallographic directions. The interest focuses on the role played by the
projectile polarization produced by cations and anions of the crystal surface.
For the considered collision system we found a polarization channel,
corresponding to the direction <110>, which is affected by this effect, while
for incidence in the direction <100> the polarization contribution is nearly
negligible. The proposed eikonal approach, including polarization effects,
provides angular projectile spectra in good agreement with the experimental
data.


title: Weak gravitational lensing

abstract:
  In this brief review I consider the advances made in weak gravitational
lensing over the last 8 years, concentrating on the large scales - cosmic
shear. I outline the theoretical developments, observational status, and the
challenges which cosmic shear must overcome to realise its full potential.
Finally I consider the prospects for probing Dark Energy and extra-dimensional
gravity theories with future experiments.


title: Soil Moisture Monitorization Using GNSS Reflected Signals

abstract:
  The use of GNSS signals as a source of opportunity for remote sensing
applications, GNSS-R, has been a research area of interest for more than a
decade. One of the possible applications of this technique is soil moisture
monitoring. The retrieval of soil moisture with GNSS-R systems is based on the
variability of the ground dielectric properties associated to soil moisture.
Higher concentrations of water in the soil yield a higher dielectric constant
and reflectivity, which incurs in signals that reflect from the Earth surface
with higher peak power. Previous investigations have demonstrated the
capability of GPS bistatic scatterometers to obtain high enough signal to noise
ratios in order to sense small changes in surface reflectivity. Furthermore,
these systems present some advantages with respect to others currently used to
retrieve soil moisture. Upcoming satellite navigation systems, such as the
European Galileo, will represent an excellent source of opportunity for soil
moisture remote sensing for various reasons. First, the existence of pilot
signals will provide the possibility to extend coherent integration times,
which will contribute to the increase of received signals SNR. In addition, the
availability of Galileo L1 and L5 signals will allow the multi-spectral
analysis of the reflected signals and the development of inversion models which
will be able to account more precisely for adverse effects, such as surface
roughness and vegetation canopy. In this paper we present some of the recent
theoretical work and experiments carried out at Starlab focusing on the
development of dedicated Soil Moisture GNSS-R systems.


title: The CMS magnet test and cosmic challenge

abstract:
  The CMS detector is under construction for imminent operation at the Large
Hadron Collider at CERN near Geneva, Switzerland. The installation and
commissioning is performed in a surface hall. Thereafter, all the main heavy
elements of the detector, the disks and wheels, are lowered in the experimental
cavern starting at the end of 2006. The superconducting magnet of CMS requires
testing before lowering, providing a unique opportunity to operate all the
sub-detectors and sub-systems together and to take data with cosmic muons as an
important commissioning test. This is called the MTCC - Magnet Test and Cosmic
Challenge. The participating systems include a 60 degree sector of the Muon
System comprising gas detectors like the drift tubes (DTs), Cathode Strip
Chambers (CSCs) and Resistive Plate Chambers (RPCs), both in the Barrel and
Endcaps. The tracking system comprises elements of the Silicon-Strip Tracker,
and parts of the Electromagnetic and Hadronic Calorimeter detected energy
depositions of the traversing muons. In this article, a description of the
operational experience and the lessons learnt are presented.


title: Evolution and Distribution of Current Helicity in Full-Sun Simulations

abstract:
  Current helicity quantifies the location of twisted and sheared non-potential
structures in a magnetic field. We simulate the evolution of magnetic fields in
the solar atmosphere in response to flux emergence and shearing by photospheric
motions. In our global-scale simulation over many solar rotations the
latitudinal distribution of current helicity develops a clear statistical
pattern, matching the observed hemispheric sign at active latitudes. In
agreement with observations there is significant scatter and intermixing of
both signs of helicity, where we find local values of current helicity density
that are much higher than those predicted by linear force-free extrapolations.
Forthcoming full-disk vector magnetograms from Solar Dynamics Observatory will
provide an ideal opportunity to test our theoretical results on the evolution
and distribution of current helicity, both globally and in single active
regions.


title: Macroscopic graphene membranes and their extraordinary stiffness

abstract:
  The properties of suspended graphene are currently attracting enormous
interest, but the small size of available samples and the difficulties in
making them severely restrict the number of experimental techniques that can be
used to study the optical, mechanical, electronic, thermal and other
characteristics of this one-atom-thick material. Here we describe a new and
highly-reliable approach for making graphene membranes of a macroscopic size
(currently up to 100 microns in diameter) and their characterization by
transmission electron microscopy. In particular, we have found that long
graphene beams supported by one side only do not scroll or fold, in striking
contrast to the current perception of graphene as a supple thin fabric, but
demonstrate sufficient stiffness to support extremely large loads, millions of
times exceeding their own weight, in agreement with the presented theory. Our
work opens many avenues for studying suspended graphene and using it in various
micromechanical systems and electron microscopy.


title: Threshold Resummation for the Top Quark Charge Asymmetry

abstract:
  We study the QCD charge asymmetry in t\bar{t} production at the Tevatron. We
investigate the role of higher orders in perturbation theory by considering the
resummation of potentially large logarithmic corrections that arise near
partonic threshold. This requires us to employ the rapidity-dependent anomalous
dimension matrices that describe color mixing due to soft gluon emission in
both quark- and gluon-initiated processes. The charge asymmetry appears
directly in the resummed cross section at next-to-leading logarithm (NLL), and
we find that the first-order expansion of the NLL resummed charge asymmetry
reproduces the known fixed-order result for the asymmetry well. Beyond its
lowest order, the asymmetric component of the cross section is enhanced by the
same leading-logarithmic threshold corrections as the total cross section. As a
result, the charge asymmetry is robust with respect to the higher-order
perturbative corrections generated by threshold resummation. We observe that
the asymmetry increases with pair mass and with scattering angle.


title: Platform-Independent Firewall Policy Representation

abstract:
  In this paper we will discuss the design of abstract firewall model along
with platform-independent policy definition language. We will also discuss the
main design challenges and solutions to these challenges, as well as examine
several differences in policy semantics between vendors and how it could be
mapped to our platform-independent language. We will also touch upon a
processing model, describing the mechanism by which an abstract policy could be
compiled into a concrete firewall policy syntax. We will discuss briefly some
future research directions, such as policy optimization and validation


title: Effective categoricity of equivalence Structures

abstract:
  An equivalence structure is a set with a single binary relation, satisfying
sentences stating that the relation is an equivalence relation. A computable
structure A is said to be $\Delta^0_\alpha$ categorical if for any computable
structure B isomorphic to A there is a $\Delta^0_\alpha$ function witnessing
that the two are isomorphic.
  The present paper gives an exact characterization of $\Delta^0_\alpha$
equivalence structures where $\alpha = 1$ or $\alpha \geq 3$. Extensive results
for $\alpha = 2$ are also given, and open cases are exhaustively described.


title: Unparticles: Interpretation and Cosmology

abstract:
  We discuss the physical interpretation of unparticles and review the
constraints from cosmology. Unparticles may be understood in terms of confined
states of a strongly-coupled scale-invariant theory, where scale-invariance
implies that the confined states have continuous masses. This picture is
consistent with the observation that unparticle operators can be represented in
terms of continuous mass fields. Finite results in scattering processes are
obtained by compensating the infinite number of unparticle final states with an
infinitesimal coupling per unparticle. As a result, unparticles are stable with
respect to decay or annihilation to Standard Model particles, implying a
one-way flow of energy from the Standard Model sector to the unparticle sector.
The qualitative properties of unparticles, which result from their continuous
mass nature, are unchanged in the case where scale-invariance is broken by a
mass gap. Unparticles with a mass gap can evade constraints from astrophysical
and 5th force considerations, in which case cosmology provides the strongest
constraints.


title: Effective categoricity of Abelian p-groups

abstract:
  Let p be a fixed prime. An Abelian p-group is an Abelian group (not
necessarily finitely generated) in which every element has for its order some
power of p. The countable Abelian p-groups are classified by Ulm's theorem, and
Khisamiev characterized the Abelian p-groups with computable copies. A
computable structure A is said to be $\Delta^0_\alpha$ categorical if for any
computable structure B isomorphic to A there is a $\Delta^0_\alpha$ function
witnessing that the two are isomorphic.
  The present paper seeks to characterize $\Delta^0_\alpha$ categoricity for
Abelian p-groups, and results of this kind are given for broad classes of
Abelian p-groups and values of $\alpha$. The remaining open cases are
exhaustively described.


title:
Instantaneous Multiphoton Ionization Rate and Initial Distribution of
  Electron Momenta

abstract:
  The Yudin-Ivanov formula [Phys. Rev. A 64, 013409 (2001)] is generalized such
that the most general analytical expression for single-electron spectra, which
includes the dependence on the instantaneous laser phase, is obtained within
the strong field approximation. No assumptions on the momentum of the electron
are made. Previously known formulas for single-electron spectra can be obtained
as approximations to the general formula.


title: Topological Entanglement Entropy and Holography

abstract:
  We study the entanglement entropy in confining theories with gravity duals
using the holographic prescription of Ryu and Takayanagi. The entanglement
entropy between a region and its complement is proportional to the minimal area
of a bulk hypersurface ending on their border. We consider a disk in 2+1
dimensions and a ball in 3+1 dimensions and find in both cases two types of
bulk hypersurfaces with different topology, similar to the case of the slab
geometry considered by Klebanov, Kutasov and Murugan. Depending on the value of
the radius, one or the other type of hypersurfaces dominates the calculation of
entanglement entropy. In 2+1 dimensions a useful measure of topological order
of the ground state is the topological entanglement entropy, which is defined
to be the constant term in the entanglement entropy of a disk in the limit of
large radius. We compute this quantity and find that it vanishes for confining
gauge theory, in accord with our expectations. In 3+1 dimensions the analogous
quantity is shown to be generically nonzero and cutoff-dependent.


title:
Instanton representation of Plebanski gravity: XIII. Canonical structure
  of the Petrov classification of nondegenerate spacetimes

abstract:
  The instanton representation of Plebanski gravity admits a natural canonical
structure where the (densitized) eigenvalues of the CDJ matrix are the basic
momentum space variables. Canonically conjugate configuration variables exist
for six distinct configurations in the full theory, referred to as quantizable
configurations. The CDJ matrix relates to the Petrov classification and
principal null directions of spacetime, which we directly correlate to these
quantizable degrees of freedom. The implication of this result is the ability
to perform a quantization procedure for spacetimes of Petrov Type I, D, and O,
using the instanton representation.


title:
A brief survey of the renormalizability of four dimensional gravity for
  generalized Kodama states

abstract:
  We continue the line of research from previous works in assessing the
suitability of the pure Kodama state both as a ground state for the generalized
Kodama states, as well as characteristic of a good semiclassical limit of
general relativity. We briefly introduce the quantum theory of fluctuations
about DeSitter spacetime, which enables one to examine some perturbative
aspects of the state. Additionally, we also motivate the concept of the cubic
tree network, which enables one to view the generalized Kodama states in
compact form as a nonlinear transformation of the pure Kodama states
parametrized by the matter content of the proper classical limit. It is hoped
that this work constitutes a first step in addressing the nonperturbative
renormalizability of general relativity in Ashtekar variables. Remaining issues
to address, including the analysis of specific matter models, include
finiteness and normalizability of the generalized Kodama state as well as
reality conditions on the Ashtekar variables, which we relegate to separate
works.


title:
Hubble Space Telescope Imaging of Bright Lyman-break Galaxy Candidates
  from the Sloan Digital Sky Survey: Not LBGs After All

abstract:
  We present deep Hubble Space Telescope ACS and NICMOS images of six bright
Lyman-break galaxy candidates that were previously discovered in the Sloan
Digital Sky Survey. We find that five of the objects are consistent with
unresolved point sources. Although somewhat atypical of the class, they are
most likely LoBAL quasars, perhaps FeLoBALs. The sixth object, J1147, has a
faint companion galaxy located ~0.8 arcsec to the southwest. The companion
contributes ~8% of the flux in the observed-frame optical and infrared. It is
unknown whether this companion is located at the same redshift as J1147.


title: Janus field theories from multiple M2 branes

abstract:
  Based on the recent proposal of N=8 superconformal gauge theories of the
multiple M2 branes, we derive (2+1)-dimensional supersymmetric Janus field
theories with a space-time dependent coupling constant. From the original
Bagger-Lambert model, we get a supersymmetric field theory with a similar
action to the N D2 branes, but the coupling varies with the space-time as a
function of the light-cone coordinate, g(t+x). Half of the supersymmetries can
be preserved. We further investigate the M2 brane action deformed by mass and
Myers-like terms. In this case, the final YM action is deformed by mass and
Myers terms and the coupling behaves as exp(\mu x) where \mu is a constant mass
parameter. Weak coupling gauge theory is continuously changed to strong
coupling in the large x region.


title: Condensed Matter Physics with Cold Polar Molecules

abstract:
  In this review chapter we focus on the many-body dynamics of cold polar
molecules in the strongly interacting regime. In particular, we discuss a
toolbox for engineering many-body Hamiltonians based on the manipulation of the
electric dipole moments of the molecules, and thus of molecular interactions,
using external static and microwave fields. This forms the basis for the
realization of novel quantum phases in these systems.


title:
Minimal Lagrangian diffeomorphisms between domains in the hyperbolic
  plane

abstract:
  Let N be a complete, simply-connected surface of constant curvature \kappa
\leq 0. Moreover, suppose that \Omega and \tilde{\Omega} are strictly convex
domains in N with the same area. We show that there exists an area-preserving
diffeomorphism from \Omega to \tilde{\Omega} whose graph is a minimal
submanifold of N \times N.


title: Gamma-ray emission from massive star forming regions

abstract:
  Recent radio observations support a picture for star formation where there is
accretion of matter onto a central protostar with the ejection of molecular
outflows that can affect the surrounding medium. The impact of a supersonic
outflow on the ambient gas can produce a strong shock that could accelerate
particles up to relativistic energies. A strong evidence of this has been the
detection of non-thermal radio emission coming from the jet termination region
of some young massive stars. In the present contribution, we study the possible
high-energy emission due to the interaction of relativistic particles,
electrons and protons, with the magnetic, photon and matter fields inside a
giant molecular cloud. Electrons lose energy via relativistic Bremsstrahlung,
synchrotron radiation and inverse Compton interactions, and protons cool mainly
through inelastic collisions with atoms in the cloud. We conclude that some
massive young stellar objects might be detectable at gamma-rays by next
generation instruments, both satellite-borne and ground based.


title: Microwave Rectification by a Carbon Nanotube Schottky Diode

abstract:
  Carbon nanotube Schottky diodes have been fabricated in an
all-photolithographic process using dissimilar contact metals on high-frequency
compatible substrates (quartz and sapphire). Diodes show near-ideal behavior,
and rectify currents of up to 100 nA and at frequencies up to 18 GHz. The
voltage and frequency dependence is used to estimate the junction capacitance
of ~10-18 F and the intrinsic device cut-off frequency of ~400 GHz.


title: Synchronous Quantum Gravity

abstract:
  The implications of restricting the covariance principle within a Gaussian
gauge are developed both on a classical and a quantum level. Hence, we
investigate the cosmological issues of the obtained Schr\"odinger Quantum
Gravity with respect to the asymptotically early dynamics of a generic
Universe. A dualism between time and the reference frame fixing is then
inferred.


title: Elementary particle interaction from a Kaluza-Klein scheme

abstract:
  We discuss properties of particles and fields in a multi-dimensional
space-time, where the geometrization of gauge interactions can be performed. As
far as spinors are concerned, we outline how the gauge coupling can be
recognized by a proper dependence on extra-coordinates and by the dimensional
reduction procedure. Finally applications to the Electro-Weak model are
presented.


title: Setting the boundary free in AdS/CFT

abstract:
  We describe a new class of boundary conditions for AdS_{d+1} under which the
boundary metric becomes a dynamical field. The key technical point is to show
that contributions from boundary counter-terms in the bulk gravitational action
render such fluctuations normalizable. In the context of AdS/CFT, the analogue
of Neumann boundary conditions for AdS promotes the CFT metric to a dynamical
field but adds no explicit gravitational dynamics; the gravitational dynamics
is just that induced by the conformal fields. Other AdS boundary conditions
couple the CFT to a gravity theory of choice. We use this correspondence to
briefly explore the coupled CFT + gravity theories and, in particular, for d=3
we show that coupling topologically massive gravity to a large N CFT preserves
the perturbative stability of the theory with negative (3-dimensional) Newton's
constant.


title: Coupled-channels calculations of $^{16}$O+$^{16}$O fusion

abstract:
  Fusion data for $^{16}$O+$^{16}$O are analyzed by coupled-channels
calculations. It is shown that the calculated cross sections are sensitive to
the couplings to the $2^+$ and $3^-$ excitation channels even at low energies,
where these channels are closed. The sensitivity to the ion-ion potential is
investigated by applying a conventional Woods-Saxon potential and the
M3Y+repulsion potential, consisting of the M3Y double-folding potential and a
repulsive term that simulates the effect of the nuclear incompressibility. The
best overall fit to the data is obtained with a M3Y+repulsion potential which
produces a shallow potential in the entrance channel. The stepwise increase in
measured fusion cross sections at high energies is also consistent with such a
shallow potential. The steps are correlated with overcoming the barriers for
the angular momenta $L$ = 12, 14, 16, and 18. To improve the fit to the
low-energy data requires a shallower potential and this causes a even stronger
hindrance of fusion at low energies. It is therefore difficult, based on the
existing fusion data, to make an accurate extrapolation to energies that are of
interest to astrophysics.


title: Spherical harmonics, invariant theory and Maxwell's poles

abstract:
  I discuss the relation between harmonic polynomials and invariant theory and
show that homogeneous, harmonic polynomials correspond to ternary forms that
are apolar to a base conic (the absolute). The calculation of Schlesinger that
replaces such a form by a polarised binary form is reviewed. It is suggested
that Sylvester's theorem on the uniqueness of Maxwell's pole expression for
harmonics is renamed the Clebsch-Sylvester theorem. The relation between
certain constructs in invariant theory and angular momentum theory is enlarged
upon and I resurrect the Joos--Weinberg matrices. Hilbert's projection
operators are considered and their generalisations by Story and Elliott are
related to similar, more recent constructions in group theory and quantum
mechanics, the ternary case being equivalent to SU(3).


title: Dark matter and the LHC

abstract:
  An abundance of astrophysical evidence indicates that the bulk of matter in
the universe is made up of massive, electrically neutral particles that form
the dark matter (DM). While the density of DM has been precisely measured, the
identity of the DM particle (or particles) is a complete mystery. In fact,
within the laws of physics as we know them (the Standard Model, or SM), none of
the particles have the right properties to make up DM. Remarkably, many new
physics extensions of the SM -- designed to address theoretical issues with the
electroweak symmetry breaking sector -- require the introduction of new
particles, some of which are excellent DM candidates. As the LHC era begins,
there are high hopes that DM particles, along with their associated new matter
states, will be produced in pp collisions. We discuss how LHC experiments,
along with other DM searches, may serve to determine the identity of DM
particles and elucidate the associated physics. Most of our discussion centers
around theories with weak-scale supersymmetry, and allows for several different
DM candidate particles.


title:
On the martingale probem associated to the 2D and 3D Stochastic
  Navier-Stokes equations

abstract:
  We consider the martingale problem associated to the Navier-Stokes in
dimension 2 or 3. Existence is well known and it has been recently shown that
markovian transition semi group associated to these equations can be
constructed. We study the Kolmogorov operator associated to these equations. It
can be defined formally as a differential operator on an infinite dimensional
Hilbert space. It can be also defined in an abstract way as the infinitesimal
generator of the transition semi group. We explicit cores for these abstract
operators and identify them with the concrete differential operators on these
cores. In dimension 2, the core is explicit and we can use a classical argument
to prove uniqueness for the martingale problem. In dimension 3, we are only
able to exhibit a core which is defined abstractly and does not allow to prove
uniqueness for the martingale problem. Instead, we exhibit a core for a
modified Kolmogorov operator which enables us to prove uniqueness for the
martingale problem up to the time the solutions are regular.


title: On one property of distances in the infinite random quadrangulation

abstract:
  We show that the Schaeffer's tree for an infinite quadrangulation only
changes locally when changing the root of the quadrangulation. This follows
from one property of distances in the infinite uniform random quadrangulation.


title: A Rotating, Inhomogeneous Dust Interior for the BTZ Black Hole

abstract:
  We present exact solutions describing rotating, inhomogeneous dust with
generic initial data in 2+1 dimensional AdS spacetime and show how they are
smoothly matched to the Banados-Teitelboim-Zanelli (BTZ) solution in the
exterior. The metrics, which are the rotational analogues of the 2+1
dimensional LeMaitre-Tolman-Bondi (LTB) family, are described by their angular
momentum and one additional constant which, together with the angular momentum,
determines the energy density of the dust cloud. The weak energy condition
gives a constraint on the angular momentum profile inside the cloud. Solutions
can be stationary or time dependent, but only the time dependent solutions can
be matched consistently to a BTZ exterior. No singularity is formed in either
the stationary or the time dependent cases.


title: On universal Lie nilpotent associative algebras

abstract:
  We study the quotient Q_i(A) of a free algebra A by the ideal M_i(A)
generated by relation that the i-th commutator of any elements is zero. In
particular, we completely describe such quotient for i=4 (for i<=3 this was
done previously by Feigin and Shoikhet). We also study properties of the ideals
M_i(A), e.g. when M_i(A)M_j(A) is contained in M_{i+j-1}(A) (by a result of
Gupta and Levin, it is always contained in M_{i+j-2}(A)).


title: Aharonov-Bohm effect with many vortices

abstract:
  The Aharonov-Bohm effect is the prime example of a zero-field-strength
configuration where a non-trivial vector potential acquires physical
significance, a typical quantum mechanical effect. We consider an extension of
the traditional A-B problem, by studying a two-dimensional medium filled with
many point-like vortices. Systems like this might be present within a Type II
superconducting layer in the presence of a strong magnetic field perpendicular
to the layer, and have been studied in different limits. We construct an
explicit solution for the wave function of a scalar particle moving within one
such layer when the vortices occupy the sites of a square lattice and have all
the same strength, equal to half of the flux quantum. From this construction we
infer some general characteristics of the spectrum, including the conclusion
that such a flux array produces a repulsive barrier to an incident low-energy
charged particle, so that the penetration probability decays exponentially with
distance from the edge.

categories: cond-mat.supr-con cond-mat.str-el hep-th math-ph math.MP quant-ph


title:
String theory and the crisis of particle physics II or the ascent of
  metaphoric arguments

abstract:
  This is a completely reformulated presentation of a previous paper with the
same title; this time with a much stronger emphasis on conceptual aspects of
string theory and a detailed review of its already more than four decades
lasting history within a broader context, including some little-known details.
Although there have been several books and essays on the sociological impact
and its philosophical implications, there is yet no serious attempt to
scrutinize its claims about particle physics using the powerful conceptual
arsenal of contemporary local quantum physics. I decided to leave the previous
first version on the arXiv because it may be interesting to the reader to
notice the change of viewpoint and the reason behind it. Other reasons for
preventing my first version to go into print and to rewrite it in such a way
that its content complies with my different actual viewpoint can be found at
the end of the article. The central message, contained in sections 5 and 6, is
that string theory is not what string theorists think and claim it is. The
widespread acceptance of a theory whose interpretation has been obtained by
metaphoric reasoning had a corroding influence on the rest of particle physics
theory as will be illustrated in several concrete cases. The work is dedicated
to the memory of Juergen Ehlers with whom I shared many critical ideas, but
their formulation in this essay is fully within my responsibility.


title: Search for Intrinsic Excitations in 152Sm

abstract:
  The 685 keV excitation energy of the first excited 0+ state in 152Sm makes it
an attractive candidate to explore expected two-phonon excitations at low
energy. Multiple-step Coulomb excitation and inelastic neutron scattering
studies of 152Sm are used to probe the E2 collectivity of excited 0+ states in
this "soft" nucleus and the results are compared with model predictions. No
candidates for two-phonon K=0+ quadrupole vibrational states are found. A 2+,
K=2 state with strong E2 decay to the first excited K=0+ band and a probable 3+
band member are established.


title: The type IIb SN 2008ax: the nature of the progenitor

abstract:
  A source coincident with the position of the type IIb supernova (SN) 2008ax
is identified in pre-explosion Hubble Space Telescope (HST) Wide Field
Planetary Camera 2 observations in three optical filters. We identify and
constrain two possible progenitor systems: (i) a single massive star that lost
most of its hydrogen envelope through radiatively driven mass loss processes,
prior to exploding as a helium-rich Wolf-Rayet star with a residual hydrogen
envelope, and (ii) an interacting binary in a low mass cluster producing a
stripped progenitor. Late time, high resolution observations along with
detailed modelling of the SN will be required to reveal the true nature of this
progenitor star.


title: The type IIb SN 2008ax: spectral and light curve evolution

abstract:
  We present spectroscopy and photometry of the He-rich supernova (SN) 2008ax.
The early-time spectra show prominent P-Cygni H lines, which decrease with time
and disappear completely about two months after the explosion. In the same
period He I lines become the most prominent spectral features. SN 2008ax
displays the ordinary spectral evolution of a type IIb supernova. A stringent
pre-discovery limit constrains the time of the shock breakout of SN 2008ax to
within only a few hours. Its light curve, which peaks in the B band about 20
days after the explosion, strongly resembles that of other He-rich
core-collapse supernovae. The observed evolution of SN 2008ax is consistent
with the explosion of a young Wolf-Rayet (of WNL type) star, which had retained
a thin, low-mass shell of its original H envelope. The overall characteristics
of SN 2008ax are reminiscent of those of SN 1993J, except for a likely smaller
H mass. This may account for the findings that the progenitor of SN 2008ax was
a WNL star and not a K supergiant as in the case of SN 1993J, that a prominent
early-time peak is missing in the light curve of SN 2008ax, and that Halpha is
observed at higher velocities in SN 2008ax than in SN 1993J.


title: Static and Dry Friction due to Multiscale Surface Roughness

abstract:
  It is shown on the basis of scaling arguments that a disordered interface
between two elastic solids will quite generally exhibit static and "dry
friction" (i.e., kinetic friction which does not vanish as the sliding velocity
approaches zero), because of Tomlinson model instabilities that occur for small
length scale asperities. This provides a possible explanation for why static
and "dry" friction are virtually always observed, and superlubricity almost
never occurs.


title: Analytification is the limit of all tropicalizations

abstract:
  We introduce extended tropicalizations for closed subvarieties of toric
varieties and show that the analytification of a quasprojective variety over a
nonarchimedean field is naturally homeomorphic to the inverse limit of the
tropicalizations of its quasiprojective embeddings.


title: Fayet-Iliopoulos Terms in AdS/CFT with Flavour

abstract:
  We construct the gravity dual of a field theory with flavour in which there
are Fayet-Iliopoulos (FI) terms present. For this purpose we turn on a constant
Kalb-Ramond B field in four internal space directions of AdS_5 x S^5 together
with a D7 brane probe wrapping AdS_5 x S^3. The B field induces
noncommutativity on the four internal directions of the D7 brane probe
perpendicular to the AdS boundary. We argue on general grounds that the moduli
space of the Higgs part of mixed Coulomb-Higgs states in the dual field theory
at the boundary is described by the ADHM equations for noncommutative
instantons on the four internal directions of the D7 brane probe. In
particular, the global symmetries match. The FI term arises as the holographic
dual of an anti-selfdual B field. We discuss possible applications for this
construction.


title: Fourier transform and related integral transforms in superspace

abstract:
  In this paper extensions of the classical Fourier, fractional Fourier and
Radon transforms to superspace are studied. Previously, a Fourier transform in
superspace was already studied, but with a different kernel. In this work, the
fermionic part of the Fourier kernel has a natural symplectic structure,
derived using a Clifford analysis approach. Several basic properties of these
three transforms are studied. Using suitable generalizations of the Hermite
polynomials to superspace (see [H. De Bie, F. Sommen, Hermite and Gegenbauer
polynomials in superspace using Clifford analysis, J. Phys. A 40 (2007)
10441-10456]) an eigenfunction basis for the Fourier transform is constructed.


title: The cosmological properties of AGN in the XMM-Newton Hard Bright Survey

abstract:
  (ABRIDGED) We investigate here the XLF of absorbed (Nh between 4E21 and E24
cm-2) and unabsorbed (Nh < 4E21 cm-2) AGN, the fraction of absorbed AGN as a
function of Lx (and z), the intrinsic Nh distribution of the AGN population,
and the XLF of Compton Thick (Nh > E24 cm-2) AGN. To carry out this
investigation we have used the XMM-Newton Hard Bright Serendipitous Sample
(HBSS) a complete sample of bright X-ray sources (fx > 7E-14 cgs) at high
galactic latitude (|b| > 20 deg) selected in the 4.5-7.5 keV energy band. The
HBSS sample is now almost completely identified (97% spectroscopic ID) and it
can be safely used for a statistical investigation. The HBSS contains 62 AGN
out of which 40 are unabsorbed (or marginally absorbed; Nh < 4E21 cm-2) and 22
are absorbed (Nh between 4E21 and E24 cm-2). Absorbed and unabsorbed AGN are
characterized by two different XLF with the absorbed AGN population being
described by a steeper XLF, if compared with the unabsorbed ones, at all
luminosities. The intrinsic fraction F of absorbed AGN with L(2-10 keV) > 3E42
cgs is 0.57+/-0.11; we find that F decreases with the intrinsic luminosity, and
probably, increases with the redshift. Our data are consistent with a flat Log
Nh distribution for Nh between E20 and E24 cm-2. Finally, by comparing the
results obtained here with those obtained using an optically selected sample of
AGN we derive, in an indirect way, the XLF of Compton Thick AGN. The density
ratio between Compton Thick AGN (Nh > E24 cm-2) and Compton Thin AGN (Nh < E24
cm-2) decreases from 1.08+/-0.44 at Lx E43 cgs to 0.23+/-0.15 at Lx E45 cgs.


title: Constraining massive neutrinos using cosmological 21 cm observations

abstract:
  Observations of neutrino oscillations show that neutrinos have mass. However,
the best constraints on this mass currently come from cosmology, via
measurements of the cosmic microwave background and large scale structure. In
this paper, we explore the prospects for using low-frequency radio observations
of the redshifted 21 cm signal from the epoch of reionization to further
constrain neutrino masses. We use the Fisher matrix formalism to compare future
galaxy surveys and 21 cm experiments. We show that by pushing to smaller scales
and probing a considerably larger volume 21 cm experiments can provide stronger
constraints on neutrino masses than even very large galaxy surveys. Finally, we
consider the possibility of going beyond measurements of the total neutrino
mass to constraining the mass hierarchies. For a futuristic, 21 cm experiment
we show that individual neutrino masses could be measured separately from the
total neutrino mass.


title:
Getting Lucky with Adaptive Optics: Fast AO Image Selection in the
  Visible with a Large Telescope

abstract:
  We describe the results from a new instrument which combines Lucky Imaging
and Adaptive Optics to give the first routine direct diffraction-limited
imaging in the visible on a 5m telescope. With fast image selection behind the
Palomar AO system we obtained Strehl ratios of 5-20% at 700 nm in a typical
range of seeing conditions, with a median Strehl of approximately 12% when 10%
of the input frames are selected. At wavelengths around 700 nm the system gave
diffraction-limited 35 milliarcsecond FWHMs. At 950 nm the output Strehl ratio
was as high as 36% and at 500 nm the FWHM resolution was as small as 42
milliarcseconds, with a low Strehl ratio but resolution improved by factor of
~20 compared to the prevailing seeing. To obtain wider fields we also used
multiple Lucky-Imaging guide stars in a configuration similar to a ground layer
adaptive optics system. With eight guide stars but very undersampled data we
obtained 300 milliarcsecond resolution across a 30X30 arcsec field of view in
i' band.


title: The Rate of Type Ia Supernovae at z~0.2 from SDSS-I Overlapping Fields

abstract:
  In the course of the Sloan Digital Sky Survey (SDSS-I), a large fraction of
the surveyed area was observed more than once due to field tiling overlap,
usually at different epochs. We utilize some of these data to perform a
supernova (SN) survey at a mean redshift of z=0.2. Our archival search, in ~ 5%
of the SDSS-I overlap area, produces 29 SN candidates clearly associated with
host galaxies. Using the Bayesian photometric classification algorithm of
Poznanski et al., and correcting for classification bias, we find 17 of the 29
candidates are likely Type Ia SNe. Accounting for the detection efficiency of
the survey and for host extinction, this implies a Type Ia SN rate of
R=14.0+(2.5,1.4}-(2.5,1.1}+/-2.5 10^-14 h(70)^2 yr^-1 L_sun^-1, where the
errors are Poisson error, systematic detection efficiency error, and systematic
classification error, respectively. The volumetric rate is
R=1.89+(0.42,0.18)-(0.34,0.15)+/-0.42 10^-5 yr^-1 h(70)^3 Mpc^-3. Our
measurement is consistent with other rate measurements at low redshift. An
order of magnitude increase in the number of SNe is possible by analyzing the
full SDSS-I database.


title:
Muon-spin rotation studies of SmFeAsO_0.85 and NdFeAsO_0.85
  superconductors

abstract:
  Measurements of the in-plane magnetic field penetration depth \lambda_{ab} in
Fe-based superconductors with the nominal composition SmFeAsO_0.85
(T_c\simeq52K) and NdFeAsO_0.85 (T_c\simeq51K) were carried out by means of
muon-spin-rotation. The absolute values of \lambda_{ab} at T=0 were found to be
189(5)nm and 195(5)nm for Sm and Nd substituted samples, respectively. The
analysis of the magnetic penetration depth data within the Uemura
classification scheme, which considers the correlation between the
superconducting transition temperature T_c and the effective Fermi temperature
T_F, reveal that both families of Fe-based superconductors (with and without
fluorine) falls to the same class of unconventional superconductors.


title:
Extrinsic orbital angular momentum of entangled photon-pairs in
  spontaneous parametric down-conversion

abstract:
  Starting from the standard Hamiltonian describing the optical non-linear
process of spontaneous parametric down-conversion, we theoretically show that
the generated entangled photon-pairs carry non-negligible orbital angular
momentum in the degrees of freedom of relative movement in the type-II cases
due to spatial symmetry breaking. We also show that the orbital angular
momentum carried by photon-pairs in these degrees of freedom escapes detection
in the traditional measurement scheme, which demands development of new
techniques for further experimental investigations.


title: Shearing active gels close to the isotropic-nematic transition

abstract:
  We study numerically the rheological properties of a slab of active gel close
o the isotropic-nematic transition. The flow behavior shows strong dependence
on sample size, boundary conditions, and on the bulk constitutive curve, which,
on entering the nematic phase, acquires an activity-induced discontinuity at
the origin. The precursor of this within the metastable isotropic phase for
contractile systems ({\em e.g.,} actomyosin gels) gives a viscosity divergence;
its counterpart for extensile ({\em e.g.,} {\em B. subtilis}) suspensions
admits instead a shear-banded flow with zero apparent viscosity.


title:
Concentration, Spin and Shape of Dark Matter Haloes as a Function of the
  Cosmological Model: WMAP1, WMAP3 and WMAP5 results

abstract:
  We investigate the effects of changes in the cosmological parameters between
the WMAP 1st, 3rd, and 5th year results on the structure of dark matter haloes.
We use a set of simulations that cover 5 decades in halo mass ranging from the
scales of dwarf galaxies (V_c ~30 km/s) to clusters of galaxies (V_c ~ 1000
km/s). We find that the concentration mass relation is a power law in all three
cosmologies. However the slope is shallower and the zero point is lower moving
from WMAP1 to WMAP5 to WMAP3. For haloes of mass log(M_200/Msun) = 10, 12, and
14 the differences in the concentration parameter between WMAP1 and WMAP3 are a
factor of 1.55, 1.41, and 1.29, respectively. As we show, this brings the
central densities of dark matter haloes in good agreement with the central
densities of dwarf and low surface brightness galaxies inferred from their
rotation curves, for both the WMAP3 and WMAP5 cosmologies. We also show that
none of the existing toy models for the concentration-mass relation can
reproduce our simulation results over the entire range of masses probed. In
particular, the model of Bullock et al (B01) fails at the higher mass end (M >
1e13 Msun), while the NFW model of Navarro, Frenk & White (1997) fails
dramatically at the low mass end (M < 1e12 Msun). We present a new model, based
on a simple modification of that of B01, which reproduces the
concentration-mass relations in our simulations over the entire range of masses
probed (1e10 Msun < M < 1e15 Msun). Haloes in the WMAP3 cosmology (at a fixed
mass) are more flatted compared to the WMAP1 cosmology, with a medium to long
axis ration reduced by ~10 %. Finally, we show that the distribution of halo
spin parameters is the same for all three cosmologies.


title: Optimal light storage with full pulse shape control

abstract:
  We experimentally demonstrate optimal storage and retrieval of light pulses
of arbitrary shape in atomic ensembles. By shaping auxiliary control pulses, we
attain efficiencies approaching the fundamental limit and achieve precise
retrieval into any predetermined temporal profile. Our techniques, demonstrated
in warm Rb vapor, are applicable to a wide range of systems and protocols. As
an example, we present their potential application to the creation of optical
time-bin qubits and to controlled partial retrieval.


title:
On the long-term tidal evolution of GJ 436b in the presence of a
  resonant companion

abstract:
  In order to explain the significant orbital eccentricity of the short-period
transiting Neptune-mass planet GJ 436b and at the same time satisfy various
observational constraints and anomalies, Ribas, Font-Ribera and Beaulieu have
proposed the existence of an eccentric low-mass companion planet at the
position of the outer 2:1 resonance. The authors demonstrate the viability of
their proposal using point-mass three-body integrations, arguing that as long
as the system appears to be dynamically stable, the short-term secular
variations ought to dominate the long-term dissipative evolution. Here we
demonstrate that if one includes tidal dissipation, both orbits circularize
after a few times the circularization timescale of the inner planet. We
conclude that with or without a nearby companion planet, in or out of the 2:1
resonance, the Q-value of GJ 436b must be near the upper bound estimate for
Neptune if the system is as young as 1 Gyr, and an order of magnitude higher if
the system is as old as 10 Gyr. We show detail of passage through resonance and
conclude that even out of resonance, a companion planet should still be
detectable through transit timing variations.


title:
Tracing the equation of state and the density of cosmological constant
  along z

abstract:
  We investigate the equation of state w(z) in a non-parametric form using the
latest compilations of distance luminosity from SNe Ia at high z. We combine
the inverse problem approach with a Monte Carlo to scan the space of priors. On
the light of these high redshift supernova data sets, we reconstruct w(z). A
comparison between a sample including the latest results at z>1 and a sample
without those results show the improvement achieved by observations of very
high z supernovae. We present the prospects to measure the variation of dark
energy density along z by this method.


title: Effects of AGN feedback on LCDM galaxies

abstract:
  We study the effects of Active Galactic Nuclei (AGN) feedback on the
formation and evolution of galaxies in a semi-analytic model of galaxy
formation. This model is an improved version of the one described by Cora
(2006), which now considers the growth of black holes (BHs) as driven by (i)
gas accretion during merger-driven starbursts and mergers with other BHs, (ii)
accretion during starbursts triggered by disc instabilities, and (iii)
accretion of gas cooled from quasi-hydrostatic hot gas haloes. It is assumed
that feedback from AGN operates in the later case. The model has been
calibrated in order to reproduce observational correlations between BH mass and
mass, velocity dispersion, and absolute magnitudes of the galaxy bulge. AGN
feedback has a strong impact on reducing or even suppressing gas cooling, an
effect that becomes important at lower redshifts. This phenomenon helps to
reproduce the observed galaxy luminosity function (LF) in the optical and near
IR bands at z=0, and the cosmic star formation rate and stellar mass functions
over a wide redshift range (0<z<5). It also allows to have a population of
massive galaxies already in place at z>1, which are mostly early-type and have
older and redder stellar populations than lower mass galaxies, reproducing the
observed bimodality in the galaxy colour distribution, and the morphological
fractions. The evolution of the optical QSO LF is also reproduced, provided
that the presence of a significant fraction of obscured QSOs is assumed. We
explore the effects of AGN feedback during starbursts and new recent
prescriptions for dynamical friction time-scales. (ABRIDGED)


title: The Sloan Lens ACS Survey. V. The Full ACS Strong-Lens Sample

abstract:
  We present the definitive data for the full sample of 131 strong
gravitational lens candidates observed with the Advanced Camera for Surveys
(ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey.
All targets were selected for higher-redshift emission lines and lower-redshift
continuum in a single Sloan Digital Sky Survey (SDSS) spectrum. The foreground
galaxies are primarily of early-type morphology, with redshifts from
approximately 0.05 to 0.5 and velocity dispersions from 160 km/s to 400 km/s;
the faint background emission-line galaxies have redshifts ranging from about
0.2 to 1.2. We confirm 70 systems showing clear evidence of multiple imaging of
the background galaxy by the foreground galaxy, as well as an additional 19
systems with probable multiple imaging. For 63 clear lensing systems, we
present singular isothermal ellipsoid and light-traces-mass gravitational lens
models fitted to the ACS imaging data. These strong-lensing mass measurements
are supplemented by magnitudes and effective radii measured from ACS
surface-brightness photometry and redshifts and velocity dispersions measured
from SDSS spectroscopy. These data constitute a unique resource for the
quantitative study of the inter-relations between mass, light, and kinematics
in massive early-type galaxies. We show that the SLACS lens sample is
statistically consistent with being drawn at random from a parent sample of
SDSS galaxies with comparable spectroscopic parameters and effective radii,
suggesting that the results of SLACS analyses can be generalized to the massive
early-type population.


title:
The Sloan Lens ACS Survey. VII. Elliptical Galaxy Scaling Laws from
  Direct Observational Mass Measurements

abstract:
  We use a sample of 53 massive early-type strong gravitational lens galaxies
with well-measured redshifts (ranging from z=0.06 to 0.36) and stellar velocity
dispersions (between 175 and 400 km/s) from the Sloan Lens ACS (SLACS) Survey
to derive numerous empirical scaling relations. The ratio between central
stellar velocity dispersion and isothermal lens-model velocity dispersion is
nearly unity within errors. The SLACS lenses define a fundamental plane (FP)
that is consistent with the FP of the general population of early-type
galaxies. We measure the relationship between strong-lensing mass M_lens within
one-half effective radius (R_e/2) and the dimensional mass variable M_dim =
G^-1 sigma_e2^2 R_e/2 to be log_10 [M_lens/10^11 M_Sun] = (1.03 +/- 0.04)
log_10 [M_dim/10^11 M_Sun] + (0.54 +/- 0.02) (where sigma_e2 is the projected
stellar velocity dispersion within R_e/2). The near-unity slope indicates that
the mass-dynamical structure of massive elliptical galaxies is independent of
mass, and that the "tilt" of the SLACS FP is due entirely to variation in total
(luminous plus dark) mass-to-light ratio with mass. Our results imply that
dynamical masses serve as a good proxies for true masses in massive elliptical
galaxies. Regarding the SLACS lenses as a homologous population, we find that
the average enclosed 2D mass profile goes as log_10 [M(<R)/M_dim] = (1.10 +/-
0.09) log_10 [R/R_e] + (0.85 +/- 0.03), consistent with an isothermal (flat
rotation curve) model when de-projected into 3D. This measurement is
inconsistent with the slope of the average projected aperture luminosity
profile at a confidence level greater than 99.9%, implying a minimum
dark-matter fraction of f_DM = 0.38 +/- 0.07 within one effective radius.
(abridged)


title: Schr\"odinger equation with delta potential in superspace

abstract:
  A superspace version of the Schr\"odinger equation with a delta potential is
studied using Fourier analysis. An explicit expression for the energy of the
single bound state is found as a function of the super-dimension M in case M is
smaller than or equal to 1. In the case when there is one commuting and 2n
anti-commuting variables also the wave function is given explicitly.


title:
Distortion and preservation of Giant resonances in Endohedral Atoms
  A@C60

abstract:
  It is demonstrated in this Letter that the effect of the fullerene shell upon
atomic Giant resonance decisively depends upon energy of photoelectrons, by
which the resonance decay. According to the prediction in [1], the Giant
resonance in Xe is strongly modified in the endohedral Xe@C60 being transformed
from a single broad and powerful maximum in Xe into four quite narrow but with
almost the same total oscillator strength. On the contrary, the 4d Giant
resonances in ions Ce3+ (the electronic structure that Ce has, when stuffed
into fullerene), in Ce4+, and Eu are considered. In none of them the 4d Giant
resonance in endohedrals is affected essentially. This is because the decay of
the Giant resonances in these endohedrals proceeds by emission of fast
photoelectrons that are almost unaffected by the C60 shell. The results
obtained give at least qualitative explanation to the fact that recent
observation of 4d Giant resonance in Ce@C82+, where the Giant resonance was
observed as a maximum without noticeable structure.


title: Krull dimension for limit groups II: aligning JSJ decompositions

abstract:
  This is the second paper in a sequence on Krull dimension for limit groups,
answering a question of Z. Sela. In it we develop the notion of a resolution of
a sequence of limit groups and show how to derive resolutions of low complexity
from resolutions of high complexity.