title:
Theoretical study of the magnetization dynamics of non-dilute
  ferrofluids

abstract:
  The paper is devoted to the theoretical investigation of the magnetodipolar
interparticle interaction effect on remagnetization dynamics in moderately
concentrated ferrofluids. We consider a homogeneous (without particle
aggregates) ferrofluid consisting of identical spherical particles and employ a
rigid dipole model, where magnetic moment of a particle is fixed with respect
to the particle itself. In particular, for the magnetization relaxation after
the external field is instantly switched off, we show that the magnetodipolar
interaction leads to the increase of the initial magnetization relaxation time.
For the complex ac-susceptibility we find that the this interaction leads to an
overall increase of the imaginary susceptibility part and shifts the peak on
its frequency dependence towards lower frequencies. Comparing results obtained
with our analytical approach (second order virial expansion) to numerical
simulation data (Langevin dynamics method), we demonstrate that the employed
virial expansion approximation gives a good qualitative description of the
ferrofluid magnetization dynamics and provides a satisfactory quantitative
agreement with numerical simulations for the dc magnetization relaxation - up
to the particle volume fraction c ~ 10% and for the ac-susceptibility - up to c
~ 5 %.


title:
Other Squashing Deformation and N=3 Superconformal Chern-Simons Gauge
  Theory

abstract:
  We consider one of the well-known solutions in eleven-dimensional
supergravity where the seven-dimensional Einstein space is given by a
SO(3)-bundle over the CP^2. By reexaming the AdS_4 supergravity scalar
potential, the holographic renormalization group flow from N=(0,1) SU(3) x
SU(2)-invariant UV fixed point to N=(3,0) SU(3) x SU(2)-invariant IR fixed
point is reinterpreted. A dual operator in three-dimensional superconformal
Chern-Simons matter theories corresponding to this RG flow is described.


title: Sigma-resonance and convergence of chiral perturbation theory

abstract:
  The dimensionless parameter $\xi' = M^2/(16 \pi^2 F^2)$, where $F$ is the
pion decay constant in the chiral limit and $M$ is the pion mass at leading
order in the quark mass, is expected to control the convergence of chiral
perturbation theory applicable to QCD. Here we demonstrate that a strongly
coupled lattice gauge theory model with the same symmetries as two-flavor QCD
but with a much lighter $\sigma$-resonance is different. Our model allows us to
study efficiently the convergence of chiral perturbation theory as a function
of $\xi'$. We first confirm that the leading low energy constants appearing in
the chiral Lagrangian are the same when calculated from the $\epsilon$-regime
and the $p$-regime. However, $\xi' \lesssim 0.002$ is necessary before 1-loop
chiral perturbation theory predicts the data within 1%. However, for $\xi' >
0.0035$ the data begin to deviate qualitatively from 1-loop chiral perturbation
theory predictions. We argue that this qualitative change is due to the
presence of a light $\sigma$-resonance in our model. Our findings may be useful
for lattice QCD studies.


title:
A new activity phase of the blazar 3C 454.3. Multifrequency observations
  by the WEBT and XMM-Newton in 2007-2008

abstract:
  We present and analyse the WEBT multifrequency observations of 3C 454.3 in
the 2007-2008 observing season, including XMM-Newton observations and near-IR
spectroscopic monitoring, and compare the recent emission behaviour with the
past one. In the optical band we observed a multi-peak outburst in July-August
2007, and other faster events in November 2007 - February 2008. During these
outburst phases, several episodes of intranight variability were detected. A mm
outburst was observed starting from mid 2007, whose rising phase was
contemporaneous to the optical brightening. A slower flux increase also
affected the higher radio frequencies, the flux enhancement disappearing below
8 GHz. The analysis of the optical-radio correlation and time delays, as well
as the behaviour of the mm light curve, confirm our previous predictions,
suggesting that changes in the jet orientation likely occurred in the last few
years. The historical multiwavelength behaviour indicates that a significant
variation in the viewing angle may have happened around year 2000. Colour
analysis reveals a complex spectral behaviour, which is due to the interplay of
different emission components. All the near-IR spectra show a prominent Halpha
emission line, whose flux appears nearly constant. The analysis of the
XMM-Newton data indicates a correlation between the UV excess and the
soft-X-ray excess, which may represent the head and the tail of the big blue
bump, respectively. The X-ray flux correlates with the optical flux, suggesting
that in the inverse-Compton process either the seed photons are synchrotron
photons at IR-optical frequencies or the relativistic electrons are those that
produce the optical synchrotron emission. The X-ray radiation would thus be
produced in the jet region from where the IR-optical emission comes.


title:
Nonequilibrium Green's functions approach to strongly correlated
  few-electron quantum dots

abstract:
  The effect of electron-electron scattering on the equilibrium properties of
few-electron quantum dots is investigated by means of nonequilibrium Green's
functions theory. The ground and equilibrium state is self-consistently
computed from the Matsubara (imaginary time) Green's function for the spatially
inhomogeneous quantum dot system whose constituent charge carriers are treated
as spin-polarized. To include correlations, the Dyson equation is solved,
starting from a Hartree-Fock reference state, within a conserving (second
order) self-energy approximation where direct and exchange contributions to the
electron-electron interaction are included on the same footing.
  We present results for the zero and finite temperature charge carrier
density, the orbital-resolved distribution functions and the self-consistent
total energies and spectral functions for isotropic, two-dimensional parabolic
confinement as well as for the limit of large anisotropy--quasi-one-dimensional
entrapment. For the considered quantum dots with N=2, 3 and 6 electrons, the
analysis comprises the crossover from Fermi gas/liquid (at large carrier
density) to Wigner molecule or crystal behavior (in the low-density limit).


title:
A combined R-matrix eigenstate basis set and finite-differences
  propagation method for the time-dependent Schr\"{od}dinger equation: the
  one-electron case

abstract:
  In this work we present the theoretical framework for the solution of the
time-dependent Schr\"{o}dinger equation (TDSE) of atomic and molecular systems
under strong electromagnetic fields with the configuration space of the
electron's coordinates separated over two regions, that is regions $I$ and
$II$. In region $I$ the solution of the TDSE is obtained by an R-matrix basis
set representation of the time-dependent wavefunction. In region $II$ a grid
representation of the wavefunction is considered and propagation in space and
time is obtained through the finite-differences method. It appears this is the
first time a combination of basis set and grid methods has been put forward for
tackling multi-region time-dependent problems. In both regions, a high-order
explicit scheme is employed for the time propagation. While, in a purely
hydrogenic system no approximation is involved due to this separation, in
multi-electron systems the validity and the usefulness of the present method
relies on the basic assumption of R-matrix theory, namely that beyond a certain
distance (encompassing region $I$) a single ejected electron is distinguishable
from the other electrons of the multi-electron system and evolves there (region
II) effectively as a one-electron system. The method is developed in detail for
single active electron systems and applied to the exemplar case of the hydrogen
atom in an intense laser field.


title: The multicomponent 2D Toda hierarchy: dispersionless limit

abstract:
  The factorization problem of the multi-component 2D Toda hierarchy is used to
analyze the dispersionless limit of this hierarchy. A dispersive version of the
Whitham hierarchy defined in terms of scalar Lax and Orlov--Schulman operators
is introduced and the corresponding additional symmetries and string equations
are discussed. Then, it is shown how KP and Toda pictures of the dispersionless
Whitham hierarchy emerge in the dispersionless limit. Moreover, the additional
symmetries and string equations for the dispersive Whitham hierarchy are
studied in this limit.


title: Vector boson scattering at high mass with ATLAS

abstract:
  In the absence of a light Higgs boson, the mechanism of electroweak symmetry
breaking will be best studied in processes of vector boson scattering at high
mass. Various models predict resonances in this channel. Scalar and vector
resonances have been investigated in the WW, WZ and ZZ channels. The ability of
ATLAS to measure the di-boson cross-section over a range of centre-of-mass
energies has been studied with particular attention paid to the reconstruction
of jet pairs with low opening angle resulting from the decays of highly boosted
vector bosons.


title:
Transient growth and evaporation kinetics at vicinal surfaces with
  non-local electromigration: step bunching instability

abstract:
  The steps at the crystal surfaces could be transparent for the migrating
adatoms. In the case of significant transparency the velocity of a given step
in a given moment is affected by detachment of atoms from rather distant steps
in rather earlier moments. The reason is that the adatom needs time to cross
many steps before attaching to a kink position. The theory of the
crystallization should account for the time dependence of the adatom
concentrations on the terraces. Such a transient growth model is developed here
for the limit of slow kinetics at the steps and fast surface diffusion. The
model accounts for the non-local electromigration of the adatoms. The central
results of this study are: - The vicinal surface with transparent steps is
unstable when the drift velocity of the adatoms multiplied with the relative
deviation of the adatom concentration from equilibrium is larger than the
critical velocity of the steps. - The most unstable mode has a wavelength
(expressed as a number of terraces) which is independent of the surface
orientation (the miscut angle of the vicinal) as well as on the magnitude of
step repulsion and the electromigration force and depends only on the relative
transparency of the steps.


title: Giving electrons a ride: nanomechanical electron shuttles

abstract:
  Nanomechanical shuttles transferring small groups of electrons or even
individual electrons from one electrode to another offer a novel approach to
the problem of controlled charge transport. Here, we report the fabrication of
shuttle-junctions consisting of a 20 nm diameter gold nanoparticle embedded
within the gap between two gold electrodes. The nanoparticle is attached to the
electrodes through a monolayer of flexible organic molecules which play the
role of springs so that when a sufficient voltage bias is applied, then
nanoparticle starts to oscillate transferring electrons from one electrode to
the other. Current-voltage characteristics for the fabricated devices have been
measured and compared with the results of our computer simulations.


title:
Resolving long-range spatial correlations in jammed colloidal systems
  using photon correlation imaging

abstract:
  We introduce a new dynamic light scattering method, termed photon correlation
imaging, which enables us to resolve the dynamics of soft matter in space and
time. We demonstrate photon correlation imaging by investigating the slow
dynamics of a quasi two-dimensional coarsening foam made of highly packed,
deformable bubbles and a rigid gel network formed by dilute, attractive
colloidal particles. We find the dynamics of both systems to be determined by
intermittent rearrangement events. For the foam, the rearrangements extend over
a few bubbles, but a small dynamical correlation is observed up to macroscopic
length scales. For the gel, dynamical correlations extend up to the system
size. These results indicate that dynamical correlations can be extremely
long-ranged in jammed systems and point to the key role of mechanical
properties in determining their nature.


title:
Three dimensional structure of penumbral filaments from Hinode
  observations

abstract:
  We analyse spectropolarimetric observations of the penumbra of the NOAA AR
10953 at high spatial resolution (0.3"). The full Stokes profiles of the Fe I
lines at 630.1 nm and 630.2 nm have been obtained with the Solar Optical
Telescope (SOT) on board the Hinode satellite. The data have been inverted by
means of the SIR code, deriving the stratifications of temperature, line of
sight velocity, and the components of the magnetic field vector in optical
depth. In order to evaluate the gas pressure and to obtain an adequate
geometrical height scale, the motion equation has been integrated for each
pixel taking into account the terms of the Lorentz force. To establish the
boundary condition, a genetic algorithm has been applied. The final resulting
magnetic field has a divergence compatible with 0 inside its uncertainties.
First analyses of the correlation of the Wilson depression with velocity,
temperature, magnetic field strength, and field inclination strongly support
the uncombed penumbral model proposed by Solanki & Montavon (1993).


title:
Momentum-resolved single-particle spectral function for TiOCl from a
  combination of density functional and variational cluster calculations

abstract:
  We present results for the momentum-resolved single-particle spectral
function of the low-dimensional system TiOCl in the insulating state, obtained
by a combination of ab initio Density Functional Theory (DFT) and Variational
Cluster (VCA) calculations. This approach allows to combine a realistic band
structure and a thorough treatment of the strong correlations. We show that it
is important to include a realistic two-dimensional band structure of TiOCl
into the effective strongly-correlated models in order to explain the spectral
weight behavior seen in angle-resolved photoemission (ARPES) experiments. In
particular, we observe that the effect of the interchain couplings is a
considerable redistribution of the spectral weight around the Gamma point from
higher to lower binding energies as compared to a purely one-dimensional model
treatment. Hence, our results support a description of TiOCl as a
two-dimensional compound with strong anisotropy and also set a benchmark on the
spectral features of correlated coupled-chain systems.


title: Faster and better: a machine learning approach to corner detection

abstract:
  The repeatability and efficiency of a corner detector determines how likely
it is to be useful in a real-world application. The repeatability is importand
because the same scene viewed from different positions should yield features
which correspond to the same real-world 3D locations [Schmid et al 2000]. The
efficiency is important because this determines whether the detector combined
with further processing can operate at frame rate.
  Three advances are described in this paper. First, we present a new heuristic
for feature detection, and using machine learning we derive a feature detector
from this which can fully process live PAL video using less than 5% of the
available processing time. By comparison, most other detectors cannot even
operate at frame rate (Harris detector 115%, SIFT 195%). Second, we generalize
the detector, allowing it to be optimized for repeatability, with little loss
of efficiency. Third, we carry out a rigorous comparison of corner detectors
based on the above repeatability criterion applied to 3D scenes. We show that
despite being principally constructed for speed, on these stringent tests, our
heuristic detector significantly outperforms existing feature detectors.
Finally, the comparison demonstrates that using machine learning produces
significant improvements in repeatability, yielding a detector that is both
very fast and very high quality.


title: Quantum boolean functions

abstract:
  In this paper we introduce the study of quantum boolean functions, which are
unitary operators f whose square is the identity: f^2 = I. We describe several
generalisations of well-known results in the theory of boolean functions,
including quantum property testing; a quantum version of the Goldreich-Levin
algorithm for finding the large Fourier coefficients of boolean functions; and
two quantum versions of a theorem of Friedgut, Kalai and Naor on the Fourier
spectra of boolean functions. In order to obtain one of these generalisations,
we prove a quantum extension of the hypercontractive inequality of Bonami,
Gross and Beckner.


title:
Reply to Comment [arXiv:0809.2310] on Universal Charge-Radius Relation
  for Subatomic and Astrophysical Compact Objects [arXiv:0804.2140, PRL100
  (2008) 151102]

abstract:
  A reply to arXiv:0809.2310, "Comment on Universal Charge-Radius Relation for
Subatomic and Astrophysical Compact Objects"
[arXiv:0804.2140,PRL100(2008)151102]


title: Studying Strange Meson Production with FOPI

abstract:
  The production of mesons containing strangeness is studied using elementary
and heavy-ion probes with the FOPI detector at GSI-SIS. The observed inclusive
cross section of neutral kaons points to an in-medium modification in the
production. The momentum dependent ratio of cross sections of light and heavy
target nuclei turns out to be a sensitive observable for the in-medium
potential strength in transport codes. The experiments will continue studying
the production of charged kaons with elementary probes including the search for
deeply bound antikaon nuclear clusters in proton proton collisions.


title:
High-energy ball milling and synthesi temperature study to improve
  superconducting properties of MgB2 ex-situ tapes and wires

abstract:
  MgB2 monofilamentary nickel-sheated tapes and wires were fabricated by means
of the ex-situ powder-in-tube method using either high-energy ball milled and
low temperature synthesized powders. All sample were sintered at 920 C in Ar
flow. The milling time and the revolution speed were tuned in order to maximize
the critical current density in field (Jc): the maximum Jc value of 6 x 10e4
A/cm2 at 5 K and 4 T was obtained corresponding to the tape prepared with
powders milled for 144h at 180rpm. Vorious synthesis temperature were also
investigated (730-900 C) finding a best Jc value for the wire prepared with
powders synthesized at 745 C. We speculate that this optimal temperature is due
to the fluidifying effect of unreacted magnesium content before the sintering
process which could better connect the grains.


title:
The Higgs sector of supersymmetric theories and the implications for
  high-energy colliders

abstract:
  One of the main motivations for low energy supersymmetric theories is their
ability to address the hierarchy and naturalness problems in the Higgs sector
of the Standard Model. In these theories, at least two doublets of scalar
fields are required to break the electroweak symmetry and to generate the
masses of the elementary particles, resulting in a rather rich Higgs spectrum.
The search for the Higgs bosons of Supersymmetry and the determination of their
basic properties is one of the major goals of high--energy colliders and, in
particular, the LHC which will soon start operation. We review the salient
features of the Higgs sector of the Minimal Supersymmetric Standard Model and
of some of its extensions and summarize the prospects for probing them at the
LHC and at the future ILC.


title: Asteroseismic age and radius of Kepler stars

abstract:
  The Kepler mission's primary goal is the detection and characterization of
Earth-like planets by observing continuously a region of sky for a nominal
period of three-and-a-half years. Over 100,000 stars will be monitored, with a
small subset of these having a cadence of 1 minute, making asteroseismic
studies for many stars possible. The subset of targets will consist of mainly
solar-type and planet-hosting stars, and these will be observed for a minimum
period of 1 month and a maximum depending on the scientific yield of the
individual target. Many oscillation frequencies will be detected in these data,
and these will be used to constrain the star's fundamental parameters. I
investigate the effect that an increase in a) the length of observation and b)
the signal quality, has on the final determination of some stellar global
parameters, such as the radius and the age.


title: Thom polynomials and Schur functions: towards the singularities $A_i(-)$

abstract:
  We develop algebro-combinatorial tools for computing the Thom polynomials for
the Morin singularities $A_i(-)$ ($i\ge 0$). The main tool is the function
$F^{(i)}_r$ defined as a combination of Schur functions with certain numerical
specializations of Schur polynomials as their coefficients. We show that the
Thom polynomial ${\cal T}^{A_i}$ for the singularity $A_i$ (any $i$) associated
with maps $({\bf C}^{\bullet},0) \to ({\bf C}^{\bullet+k},0)$, with any
parameter $k\ge 0$, under the assumption that $\Sigma^j=\emptyset$ for all
$j\ge 2$, is given by $F^{(i)}_{k+1}$. Equivalently, this says that "the
1-part" of ${\cal T}^{A_i}$ equals $F^{(i)}_{k+1}$. We investigate 2 examples
when ${\cal T}^{A_i}$ apart from its 1-part consists also of the 2-part being a
single Schur function with some multiplicity. Our computations combine the
characterization of Thom polynomials via the "method of restriction equations"
of Rim\'anyi et al. with the techniques of Schur functions.


title: Testing the potential and limitations of seismic data

abstract:
  I describe the advantage of using singular value decomposition as a
diagnostic tool for exploring the potential and limitations of seismic data.
Using stellar models coupled with the expected errors in seismic and
complementary data we can predict the precision in the stellar parameters. This
in turn allows us to quantify if and to what extent we can distinguish between
various descriptions of the interior physical processes. This method can be
applied to a wide range of astrophysical problems, and here I present one such
example which shows that the convective core overshoot parameter can be
constrained with one identified mode if the pulsating component is in an
eclipsing binary system.


title:
K-meson vector and tensor decay constants and BK-parameter from Nf=2
  tmQCD

abstract:
  We present work in progress on the computation of the K-meson vector and
tensor decay constants, as well as the B-parameter in Kaon oscillations. Our
simulations are performed in a partially quenched setup, with two dynamical
(sea) Wilson quark flavours, having a maximally twisted mass term. Valence
quarks are either of the standard or the Osterwalder-Seiler maximally twisted
variety. These two regularizations can be suitably combined in order to obtain
a BK parameter which is both multiplicatively renormalizable and O(a) improved.


title: High Performance Quantum Computing

abstract:
  The architecture scalability afforded by recent proposals of a large scale
photonic based quantum computer, utilizing the theoretical developments of
topological cluster states and the photonic chip, allows us to move on to a
discussion of massively scaled Quantum Information Processing (QIP). In this
letter we introduce the model for a secure and unsecured topological cluster
mainframe. We consider the quantum analogue of High Performance Computing,
where a dedicated server farm is utilized by many users to run algorithms and
share quantum data. The scaling structure of photonics based topological
cluster computing leads to an attractive future for server based QIP, where
dedicated mainframes can be constructed and/or expanded to serve an
increasingly hungry user base with the ideal resource for individual quantum
information processing.


title: Thom polynomials and Schur funcions: the singularities $A_3(-)$

abstract:
  Combining the "method of restriction equations" of Rim\'anyi et al. with the
techniques of symmetric functions, we establish the Schur function expansions
of the Thom polynomials for the Morin singularities $A_3: ({\bf
C}^{\bullet},0)\to ({\bf C}^{\bullet + k},0)$ for any nonnegative integer $k$.


title: Block-diagonalisation of matrices and operators

abstract:
  In this short note we deal with a constructive scheme to decompose a
continuous family of matrices $A(\rho)$ asymptotically as $\rho\to0$ into
blocks corresponding to groups of eigenvalues of the limit matrix A(0). We also
discuss the extension of the scheme to matrix families depending upon
additional parameters and operators on Hilbert spaces.


title:
Stable Mode Sorting by Two-Dimensional Parity of Photonic Transverse
  Spatial States

abstract:
  We describe a mode sorter for two-dimensional parity of transverse spatial
states of light based on an out-of-plane Sagnac interferometer. Both
Hermite-Gauss (HG) and Laguerre-Gauss (LG) modes can be guided into one of two
output ports according to the two-dimensional parity of the mode in question.
Our interferometer sorts HG_nm input modes depending upon whether they have
even or odd order n+m; it equivalently sorts LG modes depending upon whether
they have an even or odd value of their orbital angular momentum. It functions
efficiently at the single-photon level, and therefore can be used to sort
single-photon states. Due to the inherent phase stability of this type of
interferometer as compared to those of the Mach-Zehnder type, it provides a
promising tool for the manipulation and filtering of higher order transverse
spatial modes for the purposes of quantum information processing. For example,
several similar Sagnacs cascaded together may allow, for the first time, a
stable measurement of the orbital angular momentum of a true single-photon
state. Furthermore, as an alternative to well-known holographic techniques, one
can use the Sagnac in conjunction with a multi-mode fiber as a spatial mode
filter, which can be used to produce spatial-mode entangled Bell states and
heralded single photons in arbitrary first-order (n+m=1) spatial states,
covering the entire Poincare sphere of first-order transverse modes.


title: QCD Sum Rules study of meson-baryon sigma terms

abstract:
  The pion-baryon sigma terms and the strange-quark condensates of the octet
and the decuplet baryons are calculated by employing the method of quantum
chromodynamics (QCD) sum rules. We evaluate the vacuum-to-vacuum transition
matrix elements of two baryon interpolating fields in an external
isoscalar-scalar field and use a Monte Carlo-based approach to systematically
analyze the sum rules and the uncertainties in the results. We extract the
ratios of the sigma terms, which have rather high accuracy and minimal
dependence on QCD parameters. We discuss the sources of uncertainties and
comment on possible strangeness content of the nucleon and the Delta.


title: A Generalized Construction for Lumps and Non-Abelian Vortices

abstract:
  We construct the general vortex solution in a fully-Higgsed, color-flavor
locked vacuum of a non-Abelian gauge theory, where the gauge group is taken to
be the product of an arbitrary simple group and U(1), with a Fayet-Iliopoulos
term. The strict correspondence between vortices and lumps in the associated
Non-Linear Sigma-Model which arise in the limit of strong coupling is pointed
out. The construction of the vortex moduli space is derived here as a
consequence of this correspondence.


title:
Renormalization factor and effective mass of the two-dimensional
  electron gas

abstract:
  We calculate the momentum distribution of the Fermi liquid phase of the
homogeneous, two-dimensional electron gas. We show that, close to the Fermi
surface, the momentum distribution of a finite system with $N$ electrons
approaches its thermodynamic limit slowly, with leading order corrections
scaling as $N^{-1/4}$. These corrections dominate the extrapolation of the
renormalization factor, $Z$, and the single particle effective mass, $m^*$, to
the infinite system size. We show how convergence can be improved analytically.
In the range $1 \le r_s \le 10$, we get a lower renormalization factor $Z$ and
a higher effective mass, $m^*>m$, compared to the perturbative RPA values.


title: Phason Disorder Effects in the Penrose Tiling Antiferromagnet

abstract:
  We discuss the ground state of a disordered two dimensional Heisenberg
antiferromagnet. The starting structure is taken to be a perfectly
deterministic quasiperiodic tiling, and the type of disorder we consider is
geometric, involving frozen phason flips of a randomly selected subset of
sites. We consider S=1/2 quantum spins placed on the vertices of the tiling,
and interacting with the nearest neighbor spins with a uniform exchange
interaction J. We calculate the energy spectrum, ground state energy and real
space local magnetization values as a function of degree of disorder. We find
that quantum fluctuations are enhanced by disorder. The real space staggered
magnetization loses its symmetry properties and the average staggered
magnetization decreases compared to the case of the perfect Penrose tiling. We
explain our results in terms of a simple Heisenberg star cluster model that
takes into account the changes of local environments due to phason flips.


title: An Indicator Function Limit Theorem in Dynamical Systems

abstract:
  We show by a constructive proof that in all aperiodic dynamical system, for
all sequences $(a_n)_{n\in\N}\subset\R_+$ such that $a_n\nearrow\infty$ and
$\frac{a_n}{n}\to 0$ as $n\to\infty$, there exists a set $A\in\A$ having the
property that the sequence of the distributions of
$(\frac{1}{a_{n}}S_{n}(\ind_A-\mu(A)))_{n\in\N}$ is dense in the space of all
probability measures on $\R$.


title:
Robust creation of entangled states of two coupled flux qubits via
  dynamic control of the transition frequencies

abstract:
  Coherent control and the creation of entangled states are discussed in a
system of two superconducting flux qubits interacting with each other through
their mutual inductance and identically coupling to a reservoir of harmonic
oscillators. We present different schemes using continuous-wave control fields
or Stark-chirped rapid adiabatic passages, both of which rely on a dynamic
control of the qubit transition frequencies via the external bias flux in order
to maximize the fidelity of the target states. For comparison, also special
area pulse schemes are discussed. The qubits are operated around the optimum
point, and decoherence is modelled via a bath of harmonic oscillators. As our
main result, we achieve controlled robust creation of different Bell states
consisting of the collective ground and excited state of the two-qubit system.


title: Kinematical correlations: from RHIC to LHC

abstract:
  Kinematical correlations between outgoing partons (elementary particles) are
discussed in the framework of $k_t$-factorization. Different unintegrated gluon
distributions are used. I discuss correlations between charm-anticharm, jets,
photon and jet, and between leptons from semileptonic decays of heavy quarks as
well as leptons produced in the Drell-Yan mechanism. Both correlations in
azimuth as well as in the length of transverse momenta are shown. General
conclusions are drawn.


title: Anomalous avoided level crossings in a Cooper-pair box spectrum

abstract:
  We have observed a few distinct anomalous avoided level crossings and voltage
dependent transitions in the excited state spectrum of an Al/AlOx/Al
Cooper-pair box (CPB). The device was measured at 40 mK in the 15 - 50 GHz
frequency range. We find that a given level crosses the CPB spectrum at two
different gate voltages; the frequency and splitting size of the two crossings
differ and the splitting size depends on the Josephson energy of the CPB. We
show that this behavior is not only consistent with the CPB being coupled to
discrete charged "two-level" quantum systems which move atomic distances in the
CPB junctions but that the spectra provide new information about the
fluctuators, which is not available from phase qubit spectra of anomalous
avoided levels. In particular by fitting a model Hamiltonian to our data, we
extract microscopic parameters for each fluctuator, including well asymmetry,
tunneling amplitude, and the minimum hopping distance for each fluctuator. The
tunneling rates range from less than 3.5 to 13 GHz, which represent values
between 5% and 150% of the well asymmetry, and the dipole moments give a
minimum hopping distance of 0.3 to 0.8 Anstrom. We have also found that these
discrete two-level systems have a pronounced effect on the relaxation time (T1)
of the quantum states of the CPB and hence can be a source of dissipation for
superconducting quantum bits.


title: Amenable actions of amalgamated free products

abstract:
  We prove that the amalgamated free product of two free groups of rank two
over a common cyclic subgroup, admits an amenable, faithful, transitive action
on an infinite countable set. We also show that any finite index subgroup
admits such an action, which applies for example to surface groups and
fundamental groups of surface bundles over $\mathbb{S}^1$.


title: The area above the Dyck path of a permutation

abstract:
  In this paper we study a mapping from permutations to Dyck paths. A Dyck path
gives rise to a (Young) diagram and we give relationships between statistics on
permutations and statistics on their corresponding diagrams. The distribution
of the size of this diagram is discussed and a generalisation given of a parity
result due to Simion and Schmidt. We propose a filling of the diagram which
determines the permutation uniquely. Diagram containment on a restricted class
of permutations is shown to be related to the strong Bruhat poset.


title:
Photoconductivity of CdS-CdSe granular films: influence of
  microstructure

abstract:
  We study experimentally the photoconductivity of CdS-CdSe sintered granular
films obtained by the screen printing method. We mostly focus on the
dependences of photoconductivity on film's microstructure, which varies with
changing heat-treatment conditions. The maximum photoconductivity is found for
samples with compact packing of individual grains, which nevertheless are
separated by gaps. Such a microstructure is typical for films heat-treated
during an intermediate (optimal) time. In order to understand whether the
dominant mechanism of charge transfer is identical with the one in
monocrystals, we perform temperature measurements of photoresistance.
Corresponding curves have the same peculiar nonmonotonic shape as in CdSe
monocrystals, from which we conclude that the basic mechanism is also the same.
It is suggested that the optimal heat-treatment time appears as a result of a
competition between two mechanisms: improvement of film's connectivity and its
oxidation. Photoresistance is also measured in vacuum and in helium atmosphere,
which suppress oxygen and water absorption/chemisorption at intergrain
boundaries. We demonstrate that this suppression increases photoconductivity,
especially at high temperatures.


title: Chiral low-energy constants L_10 and C_87 from hadronic tau decays

abstract:
  Using recent precise hadronic tau-decay data on the V-A spectral function and
general properties of QCD such as analyticity, the operator product expansion
and chiral perturbation theory, we get accurate values for the QCD chiral order
parameters L_10 and C_87. At order p^4 we obtain
L_10^r(M_rho)=-(5.22+-0.06)10^-3, whereas at order p^6 we get
L_10^r(M_rho)=-(4.06+-0.39)10^-3 and C_87^r(M_rho) = (4.89+-0.19)10^-3 GeV^-2.


title:
One-to-one direct modeling of experiments and astrophysical scenarios:
  pushing the envelope on kinetic plasma simulations

abstract:
  There are many astrophysical and laboratory scenarios where kinetic effects
play an important role. These range from astrophysical shocks and plasma shell
collisions, to high intensity laser-plasma interactions, with applications to
fast ignition and particle acceleration. Further understanding of these
scenarios requires detailed numerical modelling, but fully relativistic kinetic
codes are computationally intensive, and the goal of one-to-one direct
modelling of such scenarios and direct comparison with experimental results is
still difficult to achieve. In this paper we discuss the issues involved in
performing kinetic plasma simulations of experiments and astrophysical
scenarios, focusing on what needs to be achieved for one-to-one direct
modeling, and the computational requirements involved. We focus on code
efficiency and new algorithms, specifically on parallel scalability issues,
namely on dynamic load balancing, and on high-order interpolation and boosted
frame simulations to optimize simulation performance. We also discuss the new
visualization and data mining tools required for these numerical experiments
and recent simulation work illustrating these techniques is also presented.


title: A benzene interference single-electron transistor

abstract:
  Interference effects strongly affect the transport characteristics of a
benzene single-electron transistor (SET) and for this reason we call it
interference SET (I-SET). We focus on the effects of degeneracies between
many-body states of the isolated benzene. We show that the particular current
blocking and selective conductance suppression occurring in the benzene I-SET
are due to interference effects between the orbitally degenerate states.
Further we study the impact of reduced symmetry due to anchor groups or
potential drop over the molecule. We identify in the quasi-degeneracy of the
involved molecular states the necessary condition for the robustness of the
results.


title: Stability and Total Variation Estimates on General Scalar Balance Laws

abstract:
  Consider the general scalar balance law $\partial_t u + \Div f(t, x,u) =
F(t,x,u)$ in several space dimensions. The aim of this note is to estimate the
dependence of its solutions from the flow $f$ and from the source $F$. To this
aim, a bound on the total variation in the space variables of the solution is
obtained. This result is then applied to obtain well posedness and stability
estimates for a balance law with a non local source.


title: Structure and dynamics of penumbral filaments

abstract:
  High-resolution observations of sunspots have revealed the existence of dark
cores inside the bright filaments of the penumbra. Here we present the
stationary solution of the heat transfer equation in a stratified penumbra
consisting of nearly horizontal magnetic flux tubes embedded in a stronger and
more vertical field. The tubes and the external medium are in horizontal
mechanical equilibrium. This model produces bright filaments with dark cores as
a consequence of the higher density of the plasma inside the flux tube, which
shifts the surface of optical depth unity toward higher (cooler) layers. Our
results suggest that the surplus brightness of the penumbra is a natural
consequence of the Evershed flow, and that magnetic flux tubes about 250 km in
diameter can explain the morphology of sunspot penumbra.


title: pi-pi Scattering in Twisted Mass Chiral Perturbation Theory

abstract:
  In this report we describe both I=2 and I=0 pi-pi scattering for twisted mass
lattice QCD utilizing twisted mass chiral perturbation theory at
next-to-leading order. Focusing on the lattice spacing (b) corrections, we
demonstrate that in the exotic I=2, I_3=+-2 channels, the leading scaling
violations of pi-pi scattering at maximal twist begin at O(m_pi^2 b^2). This is
not the case in any other isospin channel, for which the scaling violations at
maximal twist begin at O(b^2). Furthermore, we demonstrate the existence of a
mixing between the I=2, I_3 = 0 and I=0 scattering channels due to the breaking
of isospin symmetry by the twisted mass term. The mixing term, although
formally next-to-leading order, is relatively large, thus necessitating the use
of a coupled channel analysis. We argue that this mixing likely renders the
computation of the I=0 channel impractical with twisted mass lattice QCD.


title:
On Normalized Ricci Flow and Smooth Structures on Four-Manifolds with
  $b^+=1$

abstract:
  We find an obstruction to the existence of non-singular solutions to the
normalized Ricci flow on four-manifolds with $b^+=1$. By using this
obstruction, we study the relationship between the existence or non-existence
of non-singular solutions of the normalized Ricci flow and exotic smooth
structures on the topological 4-manifolds ${\mathbb C}{P}^2 # l
\overline{{\mathbb C}{P}^2}$, where $5 \leq l \leq 8$.


title: Structures conformes asymptotiquement plates

abstract:
  In the first part of this article we revisit the theory of weighted spinors
on conformal manifolds. In the second part we introduce the notions of
asymptotically flat Weyl structures and of associated mass, and we prove a
conformal version of the positive mass theorem on conformal spin manifolds.


title:
Parabolic Harnack Inequality and Local Limit Theorem for Percolation
  Clusters

abstract:
  We consider the random walk on supercritical percolation clusters in the
d-dimensional Euclidean lattice. Previous papers have obtained Gaussian heat
kernel bounds, and a.s. invariance principles for this process. We show how
this information leads to a parabolic Harnack inequality, a local limit theorem
and estimates on the Green's function.


title: Quark Mass Dependence of the QCD Equation of State on N_tau=8 Lattices

abstract:
  We currently perform calculations with an improved staggered fermion action
(p4fat3). We use a strange quark mass that has been tuned to its physical value
and light quarks of mass m_s/20 on lattices of size 32^3x8. This corresponds to
an almost physical light quark mass. We present first results on the low
temperature part of the equation of state of QCD. Through comparison with the
preliminary hotQCD results on the N_tau=8 equation of state, which have been
obtained with twice heavier light quark masses, we can quantify the quark mass
dependence of the equation of state in the low temperature regime. We also
comment on the quark mass dependence of the equation of state at high
temperature.


title:
Upper critical fields and thermally-activated transport of
  Nd(O_0.7F_0.3)FeAs single crystal

abstract:
  We present measurements of the resistivity and the upper critical field H_c2
of Nd(O_0.7F_0.3)FeAs single crystals in strong DC and pulsed magnetic fields
up to 45 T and 60 T, respectively. We found that the field scale of H_c2 is
comparable to ~100 T of high T_c cuprates. H_c2(T) parallel to the c-axis
exhibits a pronounced upward curvature similar to what was extracted from
earlier measurements on polycrystalline samples. Thus this behavior is indeed
an intrinsic feature of oxypnictides, rather than manifestation of vortex
lattice melting or granularity. The orientational dependence of H_c2 shows
deviations from the one-band Ginzburg-Landau scaling. The mass anisotropy
decreases as T decreases, from 9.2 at 44K to 5 at 34K. Spin dependent
magnetoresistance and nonlinearities in the Hall coefficient suggest
contribution to the conductivity from electron-electron interactions modified
by disorder reminiscent that of diluted magnetic semiconductors. The Ohmic
resistivity measured below T_c but above the irreversibility field exhibits a
clear Arrhenius thermally activated behavior over 4-5 decades. The activation
energy has very different field dependencies for H||ab and H\perp ab. We
discuss to what extent different pairing scenarios can manifest themselves in
the observed behavior of H_{c2}, using the two-band model of superconductivity.
The results indicate the importance of paramagnetic effects on H_c2(T),which
may significantly reduce H_c2(0) as compared toH_c2(0)~200-300 T based on
extrapolations of H_c2(T) near T_c down to low temperatures.


title: A crystal cleavage mechanism for UHV STM

abstract:
  A device for UHV cleavage of crystal specimens for the use with STM has been
suggested and developed. We present a device suitable for the precise cleavage
of semiconductors. The device needs only small space and can be easily mounted
in a small and compact UHV chamber equipped with a wobble stick manipulator. In
order to prove the technique UHV STM measurements on InAs(110) surfaces with
different bulk conductivities (p-and n-type) have been performed.


title: Effect of pressure and Ir substitution in YbRh2Si2

abstract:
  In this article we present a study of the electrical resistivity of
Yb(Rh-xIrx)2Si2, x=0.06, under high pressure and in magnetic field. Ir
substitution is expanding the unit cell and leads to a suppression of the
antiferromagnetic transition temperature to zero, where eventually a quantum
critical point (QCP) exists. We applied hydrostatic pressure to reverse the
effect of substitution. Our results indicate that Yb(Rh0.94Ir0.06)2Si2 is
situated in the immediate proximity to a volume controlled QCP, but still on
the magnetically ordered side of the phase diagram. The temperature - pressure
phase diagram of Yb(Rh0.94Ir0.06)2Si2 resembles that of the pure compound.
Substitution acts mainly as chemical pressure. Disorder introduced by
substitution has only minor effects.


title:
Thermodynamic properties and electrical conductivity of strongly
  correlated plasma media

abstract:
  We study thermodynamic properties and the electrical conductivity of dense
hydrogen and deuterium using three methods: classical reactive Monte Carlo
(REMC), direct path integral Monte Carlo (PIMC) and a quantum dynamics method
in the Wigner representation of quantum mechanics. We report the calculation of
the deuterium compression quasi-isentrope in good agreement with experiments.
We also solve the Wigner-Liouville equation of dense degenerate hydrogen
calculating the initial equilibrium state by the PIMC method. The obtained
particle trajectories determine the momentum-momentum correlation functions and
the electrical conductivity and are compared with available theories and
simulations.


title:
Diffusion of two particles with a finite interaction potential in one
  dimension

abstract:
  We investigate the dynamics of two interacting diffusing particles in an
infinite effectively one dimensional system; the particles interact through a
step-like potential of width b and height phi_0 and are allowed to pass one
another. By solving the corresponding 2+1-variate Fokker-Planck equation an
exact result for the two particle conditional probability density function
(PDF) is obtained for arbitrary initial particle positions. From the
two-particle PDF we obtain the overtake probability, i.e. the probability that
the two particles has exchanged positions at time t compared to the initial
configuration. In addition, we calculate the trapping probability, i.e. the
probability that the two particles are trapped close to each other (within the
barrier width b) at time t, which is mainly of interest for an attractive
potential, phi_0<0. We also investigate the tagged particle PDF, relevant for
describing the dynamics of one particle which is fluorescently labeled. Our
analytic results are in excellent agreement with the results of stochastic
simulations, which are performed using the Gillespie algorithm.


title:
Anomalous electron-phonon interaction in doped LaOFeAs: a First
  Principles calculation

abstract:
  We present first principles calculations of the atomic and electronic
structure of electron-doped LaOFeAs. We find that whereas the undoped compound
has an antiferromagnetic arrangement of magnetic moments at the Fe atoms, the
doped system becomes non magnetic at a critical electron concentration. We have
studied the electron-phonon interaction in the doped paramagnetic phase. For
the $A_{1g}$ phonon, the separation between the As and Fe planes induces a
non-collinear arrangement of the Fe magnetic moments. This arrangement is anti
parallel for interactions mediated by As, and perpendicular for Fe-Fe direct
interactions, thus avoiding frustration. This coupling of magnetism with
vibrations induces anharmonicities and an electron-phonon interaction much
larger than in the pure paramagnetic case. We propose that such enhanced
interactions play an essential role in superconducting compounds close to an
atiferromagnetic phase transition.


title: SrFeAsF as a parent compound for iron pnictide superconductors

abstract:
  We have successfully synthesized the fluo-arsenide SrFeAsF, a new parent
phase with the ZrCuAsSi structure. The temperature dependence of resistivity
and dc magnetization both reveal an anomaly at about T_{an} = 173 K, which may
correspond to the structural and/or Spin-Density-Wave (SDW) transition. Strong
Hall effect and magnetoresistance were observed below T_{an}. Interestingly,
the Hall coefficient R_H is positive below T_{an}, which is opposite to the
cases in the two parent phases of FeAs-based systems known so far, i.e.,
LnFeAsO (Ln = rare earth elements) and (Ba, Sr)Fe_2As_2 where the Hall
coefficient R_H is negative. This strongly suggests that the gapping to the
Fermi surfaces induced by the SDW order is more complex than we believed before
that it removes the density of states on some Fermi pockets and leaves one of
the electron pockets less-gapped or un-gapped. Our data clearly show that it is
possible for the parent phase to have electron-like or hole-like charge
carriers.


title: The OPERA Long Baseline Experiment: Status and First Results

abstract:
  OPERA (Oscillation Project with Emulsion tRacking Apparatus)is an
international collaboration between Europe and Asia, aiming to give the first
direct proof of tau neutrino appearance in a pure muon neutrino beam, in order
to validate the hypothesis for atmospheric neutrino oscillations. The first
european long baseline neutrino beam called CNGS is produced at CERN and sent
in the direction of the Gran Sasso underground laboratory 730 km away, where
the OPERA detector is located. Since 2006 the electronic detector part is fully
commissioned and running. Cosmic ray events have been recorded on a regular
basis and the first neutrino beam events have been observed in the target
elements made of very precise emulsion films and lead sheets during the last
run in autumn 2007. This paper reviews the status of the detector, the beam
performances, the first results from the neutrino event analysis and the
prospects.


title: A visible factor of the special L-value

abstract:
  Let~$A$ be a quotient of $J_0(N)$ associated to a newform $f$ such that the
special $L$-value of $A$ (at $s=1$) is non-zero. We give a formula for the
ratio of the special $L$-value to the real period of $A$ that expresses this
ratio as a rational number. We extract an integer factor from the numerator of
this formula; this factor is non-trivial in general and is related to certain
congruences of $f$ with eigenforms of positive analytic rank. We use the
techniques of visibility to show that, under certain hypotheses (which includes
the first part of the Birch and Swinnerton-Dyer conjecture on rank), if an odd
prime $q$ divides this factor, then $q$ divides either the order of the
Shafarevich-Tate group or the order of a component group of $A$. Suppose $p$ is
an odd prime such that $p^2$ does not divide $N$, $p$ does not divide the order
of the rational torsion subgroup of $A$, and $f$ is congruent modulo a prime
ideal over $p$ to an eigenform whose associated abelian variety has positive
Mordell-Weil rank. Then we show that $p$ divides the factor mentioned above; in
particular, $p$ divides the numerator of the ratio of the special $L$-value to
the real period of $A$. Both of these results are as implied by the second part
of the Birch and Swinnerton-Dyer conjecture, and thus provide theoretical
evidence towards the conjecture.


title: The spatial distribution of polar hydrogen deposits on the Moon

abstract:
  A new analysis of the Lunar Prospector epithermal neutron data is presented,
providing an improved map of the distribution of hydrogen near to the lunar
poles. This is achieved using a specially developed pixon image reconstruction
algorithm to deconvolve the instrumental response of the Lunar Prospector's
neutron spectrometer from the observed data, while simultaneously suppressing
the statistical noise. The results show that these data alone require the
hydrogen to be concentrated into the cold traps at up to 1 wt% water-equivalent
hydrogen. This combination of localisation and high concentration suggests that
the hydrogen is present either in the form of a volatile compound or as solar
wind protons implanted into small regolith grains.


title: On Izumi's theorem on comparison of valuations

abstract:
  We prove that the sequence of MacLane key polynomials constructed in
\cite{Mac1} and \cite{Sp2} for a valuation extension $(K,\nu)\subset
(K(x),\mu)$ is finite, provided that both $\nu$ and $\mu$ are divisorial and
$\mu$ is centered over an analytically irreducible local domain
$(R,\frak{m})\subset K[x]$. As a corollary, we prove Izumi's theorem on
comparison of divisorial valuations. %We show that the existence of Izumi
constants is equivalent to the finiteness of the sequence of the MacLane
key-polynomials. We give explicit bounds for the Izumi constant in terms of the
key polynomials of the valuations. We show that this bound can be attained in
some cases.


title: Aspects of dual models many years ago

abstract:
  Invited contribution to the collection of articles: `The Birth of String
Theory', edited by Andrea Cappelli, Elena Castellani, Filippo Colomo and Paolo
Di Vecchia.


title: Gamma-Ray Burst at the extreme: "the naked-eye burst" GRB 080319B

abstract:
  On 19 March 2008, the northern sky was the stage of a spectacular optical
transient that for a few seconds remained visible to the naked eye. The
transient was associated with GRB 080319B, a gamma-ray burst at a luminosity
distance of about 6 Gpc (standard cosmology), making it the most luminous
optical object ever recorded by human kind. We present comprehensive sky
monitoring and multi-color optical follow-up observations of GRB 080319B
collected by the RAPTOR telescope network covering the development of the
explosion and the afterglow before, during, and after the burst. The extremely
bright prompt optical emission revealed features that are normally not
detectable. The optical and gamma-ray variability during the explosion are
correlated, but the optical flux is much greater than can be reconciled with
single emission mechanism and a flat gamma-ray spectrum. This extreme optical
behavior is best understood as synchrotron self-Compton model (SSC). After a
gradual onset of the gamma-ray emission, there is an abrupt rise of the prompt
optical flux suggesting that variable self-absorption dominates the early
optical light curve. Our simultaneous multi-color optical light curves
following the flash show spectral evolution consistent with a rapidly decaying
red component due to large angle emission and the emergence of a blue forward
shock component from interaction with the surrounding environment. While
providing little support for the reverse shock that dominates the early
afterglow, these observations strengthen the case for the universal role of the
SSC mechanism in generating gamma-ray bursts.


title: Strangeness and glue in the nucleon from lattice QCD

abstract:
  We study the strangeness contribution to nucleon matrix elements using Nf=2+1
dynamical clover fermion configurations generated by the CP-PACS/JLQCD
collaboration. In order to evaluate the disconnected insertion (DI), we use the
Z(4) stochastic method, along with unbiased subtraction from the hopping
parameter expansion which reduces the off-diagonal noises in the stochastic
method. Furthermore, we find that using many nucleon sources for each
configuration is effective in improving the signal. Our results for the quark
contribution to the first moment <x>_q in the DI, and the strangeness magnetic
moment show that the statistical errors are under control with these
techniques. We also study the gluonic contribution to the nucleon using the
overlap operator to construct the gauge field tensor, F_{mu,nu}. The
application to the calculation of first moment, <x>_G, gives a good signal in
quenched lattice QCD.


title:
Energetic selection of ordered states in a model of the Er2Ti2O7
  frustrated pyrochlore XY antiferromagnet

abstract:
  We consider the possibility that the discrete long-range ordered states of
Er2Ti2O7 are selected energetically at the mean field level as an alternative
scenario that suggests selection via thermal fluctuations. We show that nearest
neighbour exchange interactions alone are not sufficient for this purpose, but
that anisotropies arising from excited single ion crystal field states in
Er2Ti2O7, together with appropriate anisotropic exchange interactions, can
produce the required long range order. However, the effect of the single ion
anisotropies is rather weak so we expect thermal or quantum fluctuations, in
some guise, to be ultimately important in this material. We reproduce recent
experimental results for the variation of magnetic Bragg peak intensities as a
function of magnetic field.


title:
Dynamics in the Metabasin Space of a Lennard-Jones Glass Former:
  Connectivity and Transition Rates

abstract:
  Using simulations, we construct the effective dynamics in metabasin space for
a Lennard-Jones glass-former. Metabasins are identified via a scheme that
measures transition rates between inherent structures, and generates clusters
of inherent structures by drawing in branches that have the largest transition
rates. The effective dynamics is shown to be Markovian but differs
significantly from the simplest trap models. We specifically show that
retaining information about the connectivity in metabasin space is crucial for
reproducing the slow dynamics observed in this system.


title:
Investigation of Vertical Spiral Resonators for Low Frequency
  Metamaterial Design

abstract:
  This paper thoroughly explores the characteristics of vertical spiral
resonators (VSR). They exhibit rela-tively high Q factors and sizes around a
few percent of the free space wavelength, which make them ideal candi-dates for
assembling metamaterial devices. A quasistatic model of VSR is obtained from
simple analytical ex-pressions, and the effects of certain geometrical
parameters on the resonant frequency are investigated.


title: Dynamic assignment: there is an equilibrium !

abstract:
  Given a network with a continuum of users at some origins, suppose that the
users wish to reach specific destinations, but that they are not indifferent to
the time needed to reach their destination. They may have several possibilities
(of routes or deparure time), but their choices modify the travel times on the
network. Hence, each user faces the following problem: given a pattern of
travel times for the different possible routes that reach the destination, find
a shortest path. The situation in a context of perfect information is a
so-called Nash equilibrium, and the question whether there is such an
equilibrium and of finding it if it exists is the so-called equilibrium
assignment problem. It arises for various kind of networks, such as computers,
communication or transportation network. When each user occupies permanently
the whole route from the origin to its destination, we call it the static
assignment problem, which has been extensively studied with pioneers works by
Wardrop or Beckmann. A less studied, but more realistic, and maybe more
difficult, problem is when the time needed to reach an arc is taken into
account. We speak then of a dynamic assignment problem. Several models have
been proposed. For some of them, the existence of an equilibrium has been
proved, but always under some technical assumptions or in a very special case
(a network with one arc for the case when the users may chose their departure
time). The present paper proposes a compact model, with minimal and natural
assumptions. For this model, we prove that there is always an equilibrium. To
our knowledge, this imply all previous results about existence of an
equilibrium for the dynamic assignment problem.


title:
Visibility and the Birch and Swinnerton-Dyer conjecture for analytic
  rank one

abstract:
  Let $E$ be an optimal elliptic curve over $\Q$ of conductor $N$ having
analytic rank one, i.e., such that the $L$-function $L_E(s)$ of $E$ vanishes to
order one at $s=1$. Let $K$ be a quadratic imaginary field in which all the
primes dividing $N$ split and such that the $L$-function of $E$ over $K$
vanishes to order one at $s=1$. Suppose there is another optimal elliptic curve
over $\Q$ of the same conductor $N$ whose Mordell-Weil rank is greater than one
and whose associated newform is congruent to the newform associated to $E$
modulo an integer $r$. The theory of visibility then shows that under certain
additional hypotheses, $r$ divides the order of the Shafarevich-Tate group of
$E$ over $K$. We show that under somewhat similar hypotheses, $r$ divides the
order of the Shafarevich-Tate group of $E$ over $K$. We show that under
somewhat similar hypotheses, $r$ also divides the Birch and Swinnerton-Dyer
{\em conjectural} order of the Shafarevich-Tate group of $E$ over $K$, which
provides new theoretical evidence for the second part of the Birch and
Swinnerton-Dyer conjecture in the analytic rank one case.


title:
A representation-valued relative Riemann-Hurwitz theorem and the
  Hurwitz-Hodge bundle

abstract:
  We provide a formula describing the G-module structure of the Hurwitz-Hodge
bundle for admissible G-covers in terms of the Hodge bundle of the base curve,
and more generally, for describing the G-module structure of the push-forward
to the base of any sheaf on a family of admissible G-covers. This formula can
be interpreted as a representation-ring-valued relative Riemann-Hurwitz formula
for families of admissible G-covers.


title: Quasisymmetric Schur functions

abstract:
  We introduce a new basis for quasisymmetric functions, which arise from a
specialization of nonsymmetric Macdonald polynomials to standard bases, also
known as Demazure atoms. Our new basis is called the basis of quasisymmetric
Schur functions, since the basis elements refine Schur functions in a natural
way. We derive expansions for quasisymmetric Schur functions in terms of
monomial and fundamental quasisymmetric functions, which give rise to
quasisymmetric refinements of Kostka numbers and standard (reverse) tableaux.
  From here we derive a Pieri rule for quasisymmetric Schur functions that
naturally refines the Pieri rule for Schur functions. After surveying
combinatorial formulas for Macdonald polynomials, including an expansion of
Macdonald polynomials into fundamental quasisymmetric functions, we show how
some of our results can be extended to include the $t$ parameter from
Hall-Littlewood theory.


title:
Numerical and experimental studies of resonators with reduced resonant
  frequencies and small electrical sizes

abstract:
  Methods on reducing resonant frequencies and electrical sizes of resonators
are reported in this paper. Theoreti-cal and numerical analysis has been used
and the results for the broadside-coupled resonators from both studies exhibit
good agreement. Initial fabrication techniques are proposed and measurement
results are compared with simulations. Further high resolution techniques have
been envisaged to enhance the performance of the resona-tors. This class of
small resonators with low resonant frequencies indicates a variety of
applications in the design of microwave devices.


title: High-fidelity fast quantum transport with imperfect controls

abstract:
  Effective transport of quantum information is an essential element of quantum
computation. We consider the problem of transporting a quantum state by using a
moving potential well, while maintaining the encoded quantum information. In
particular, we look at a set of cases where the input control defining the
position of the potential well is subject to different types of distortion,
each of which is motivated by experimental considerations. We show that even
under these conditions, we are able to perfectly transfer the quantum
information non-adiabatically over any given distance.


title: Critical points of pairs of varieties of algebras

abstract:
  For a class V of algebras, denote by Conc(V) the class of all semilattices
isomorphic to the semilattice Conc(A) of all compact congruences of A, for some
A in V. For classes V1 and V2 of algebras, we denote by crit(V1,V2) the
smallest cardinality of a semilattice in Conc(V1) which is not in Conc(V2) if
it exists, infinity otherwise. We prove a general theorem, with categorical
flavor, that implies that for all finitely generated congruence-distributive
varieties V1 and V2, crit(V1,V2) is either finite, or aleph_n for some natural
number n, or infinity. We also find two finitely generated modular lattice
varieties V1 and V2 such that crit(V1,V2)=aleph_1, thus answering a question by
J. Tuma and F. Wehrung.


title: Leptonic B decays at BaBar

abstract:
  We will present the most recent results on leptonic B decays
  $B^{\pm(0)} \to K^{* \pm (0)} \nu \bar{\nu}$ and
  $B^{\pm} \to \mu^{\pm} \nu$, based on the data collected by the BaBar
detector at PEP-II, an asymmetric $e^+ e^-$ collider at the center of mass
energy of the $\Upsilon(4S)$ resonance .


title:
HINODE Observations of Chromospheric Brightenings in the Ca II H Line
  during small-scale Flux Emergence Events

abstract:
  \ion{Ca}{2} H emission is a well-known indicator of magnetic activity in the
Sun and other stars. It is also viewed as an important signature of
chromospheric heating. However, the \ion{Ca}{2} H line has not been used as a
diagnostic of magnetic flux emergence from the solar interior. Here we report
on Hinode observations of chromospheric \ion{Ca}{2} H brightenings associated
with a repeated, small-scale flux emergence event. We describe this process and
investigate the evolution of the magnetic flux, G-band brightness, and
\ion{Ca}{2} H intensity in the emerging region. Our results suggest that energy
is released in the chromosphere as a consequence of interactions between the
emerging flux and the pre-existing magnetic field, in agreement with recent 3D
numerical simulations.


title:
Three useful bounds in quantum mechanics - easily obtained by Wiener
  integration

abstract:
  In a reasonably self-contained and explicit presentation we illustrate the
efficiency of the Feynman-Kac formula for the rigorous derivation of three
inequalities of interest in non-relativistic quantum mechanics.


title: Ordering dynamics in the presence of multiple phases

abstract:
  The dynamics of the 2D Potts ferromagnet when quenched below the transition
temperature is investigated in the case of discontinuous phase transition,
which is interesting for understandingthe non equilibrium dynamics of systems
with many competing equivalent low temperature phases, that appears to be not
much explored. After briefly reviewing some recent findings, we focus on the
numerical study of quenches just below the transition temperature on square
lattices. We show that, up to a certain time, metastable states can be observed
for which energy stays constant above the equilibrium energy and the
self-correlation function displays a fast decay.


title:
Semiprojectivity of universal C*-algebras generated by algebraic
  elements

abstract:
  Let $p$ be a polynomial in one variable whose roots either all have
multiplicity more than 1 or all have multiplicity exactly 1. It is shown that
the universal $C^*$-algebra of a relation $p(x)=0$, $\|x\| \le 1$ is
semiprojective. In the case of all roots multiple it is shown that the
universal $C^*$-algebra is also residually finite-dimensional. Applications to
polynomially compact operators are given.


title: Widths of tetraquarks with open charm

abstract:
  In the framework of coupled-channel formalism the relativistic four-quark
equations are found. The dynamical mixing of the meson-meson states with the
four-quark states is considered. The four-quark amplitudes of the tetraquarks
with open charm, including u, d, s, c quarks, are constructed. The poles of
these amplitudes determine the masses and widths of tetraquarks.


title: POET: POlarimeters for Energetic Transients

abstract:
  POET (Polarimeters for Energetic Transients) is a Small Explorer mission
concept proposed to NASA in January 2008. The principal scientific goal of POET
is to measure GRB polarization between 2 and 500 keV. The payload consists of
two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of
polarization measurements in the energy range from 2-15 keV and a high energy
polarimeter (Gamma-Ray Polarimeter Experiment -- GRAPE) that will measure
polarization in the 60-500 keV energy range. Spectra will be measured from 2
keV up to 1 MeV. The POET spacecraft provides a zenith-pointed platform for
maximizing the exposure to deep space. Spacecraft rotation will provide a means
of effectively dealing with systematics in the polarization response. POET will
provide sufficient sensitivity and sky coverage to measure statistically
significant polarization for up to 100 GRBs in a two-year mission. Polarization
data will also be obtained for solar flares, pulsars and other sources of
astronomical interest.


title: The Maximal C*-Algebra of Quotients as an Operator Bimodule

abstract:
  We establish a description of the maximal C*-algebra of quotients of a unital
C*-algebra $A$ as a direct limit of spaces of completely bounded bimodule
homomorphisms from certain operator submodules of the Haagerup tensor product
$A\otimes_h A$ labelled by the essential closed right ideals of $A$ into $A$.
In addition the invariance of the construction of the maximal C*-algebra of
quotients under strong Morita equivalence is proved.


title: Propagation of ultra high energy cosmic rays

abstract:
  We briefly describe the energy loss processes of ultrahigh energy protons,
heavier nuclei and gamma rays in interactions with the universal photon fields
of the Universe. We then discuss the modification of the accelerated cosmic ray
energy spectrum in propagation by the energy loss processes and the charged
cosmic ray scattering in the extragalactic magnetic fields. The energy lost by
the ultrahigh energy cosmic rays goes into gamma rays and neutrinos that carry
additional information about the sources of highest energy particles. The new
experimental results of the HiRes and the Auger collaborations are discussed in
view of the predictions from propagation calculations.


title: Coherent spin rotation in the presence of a phonon-bottleneck effect

abstract:
  A characteristic of spin reversal in the presence of phonon-bottleneck is the
deviation of the magnetization cycle from a reversible function into an opened
hysterezis cycle. In recent experiments on molecular magnets (e.g. V$_{15}$ and
Ru$_2$), the zero-field level repulsion was sufficiently large to ensure an
otherwise adiabatic passage through zero-field and the magnetization curves can
be described by using only a phonon-bottleneck model. Here, we generalize the
phonon-bottleneck model into a model able to blend the non-adiabatic dynamics
of spins with the presence of a non-equilibrium phonon bath. In this simple
phenomenological model, Bloch equations are written in the eigenbasis of the
effective spin Hamiltonian, considered to be a two-level system at low
temperatures. The relaxation term is given by the phonon-bottleneck mechanism.
To the expense of calculus time, the method can be generalized to multi-level
systems, where the notion of Bloch sphere does not apply but the density matrix
formalism is still applicable.


title: A Causal Alternative for c=0 Strings

abstract:
  We review a recently discovered continuum limit for the one-matrix model
which describes "causal" two-dimensional quantum gravity. The behaviour of the
quantum geometry in this limit is different from the quantum geometry of
Euclidean two-dimensional quantum gravity defined by taking the "standard"
continuum limit of the one-matrix model. Geodesic distance and time scale with
canonical dimensions in this new limit, contrary to the situation in Euclidean
two-dimensional quantum gravity. Remarkably, whenever we compare, the known
results of (generalized) causal dynamical triangulations are reproduced exactly
by the one-matrix model. We complement previous results by giving a geometrical
interpretation of the new model in terms of a generalization of the loop
equation of Euclidean dynamical triangulations. In addition, we discuss the
time evolution of the quantum geometry.


title:
First-principles statistical mechanics approach to step decoration at
  surfaces

abstract:
  Using a first-principles parameterized lattice-gas Hamiltonian we study the
adsorbate ordering behavior at atomic steps of a Pd(100) surface exposed to an
oxygen environment. We identify a wide range of gas-phase conditions comprising
near atmospheric pressures and elevated temperatures around 900 K, in which the
step is decorated by a characteristic O zigzag arrangement. For catalytic
processes like the high-temperature combustion of methane that operate under
these conditions our approach thus provides first insight into the structure
and composition at a prominent defect on the working surface.


title:
Nonlinear rheological properties of dense colloidal dispersions close to
  a glass transition under steady shear

abstract:
  The nonlinear rheological properties of dense colloidal suspensions under
steady shear are discussed within a first principles approach. It starts from
the Smoluchowski equation of interacting Brownian particles in a given shear
flow, derives generalized Green-Kubo relations, which contain the transients
dynamics formally exactly, and closes the equations using mode coupling
approximations. Shear thinning of colloidal fluids and dynamical yielding of
colloidal glasses arise from a competition between a slowing down of structural
relaxation, because of particle interactions, and enhanced decorrelation of
fluctuations, caused by the shear advection of density fluctuations. The
integration through transients approach takes account of the dynamic
competition, translational invariance enters the concept of wavevector
advection, and the mode coupling approximation enables to quantitatively
explore the shear-induced suppression of particle caging and the resulting
speed-up of the structural relaxation. Extended comparisons with shear stress
data in the linear response and in the nonlinear regime measured in model
thermo-sensitive core-shell latices are discussed. Additionally, the single
particle motion under shear observed by confocal microscopy and in computer
simulations is reviewed and analysed theoretically.


title: Universality in open system entanglement dynamics

abstract:
  We show that the entanglement evolution of an open quantum system is the same
for the vast majority of initial pure states, in the limit of large Hilbert
space dimensions.


title: Calculation of the spectra of the superheavy element Z=112

abstract:
  Accurate ab initio calculations of the energy levels of the superheavy
elements Z=112 are presented. Relativistic Hartree-Fock and configuration
interaction methods are combined with the many-body perturbation theory to
construct the many-electron wave function for valence electrons and to include
core-valence correlations. Two different approaches in which the element is
treated as a system with two or twelve external electrons above closed shells
are used and compared. Similar calculations for mercury are used to control the
accuracy of the calculations. The results are compared with other calculations.


title: Universality in the stock exchange

abstract:
  We analyze the constituents stocks of the Dow Jones Industrial Average
(DJIA30) and the Standard & Poor's 100 index (S&P100) of the NYSE stock
exchange market. Surprisingly, we discover the data collapse of the histograms
of the DJIA30 price fluctuations and of the S&P100 price fluctuations to the
universal non-parametric Bramwell-Holdsworth-Pinton (BHP) distribution. Since
the BHP probability density function appears in several other dissimilar
phenomena, our result reveals an universal feature of the stock exchange
market.


title:
Universal emission intermittency in quantum dots, nanorods, and
  nanowires

abstract:
  Virtually all known fluorophores, including semiconductor nanoparticles,
nanorods and nanowires exhibit unexplainable episodes of intermittent emission
blinking. A most remarkable feature of the fluorescence intermittency is a
universal power law distribution of on- and off-times. For nanoparticles the
resulting power law extends over an extraordinarily wide dynamic range: nine
orders of magnitude in probability density and five to six orders of magnitude
in time. The exponents hover about the ubiquitous value of -3/2. Dark states
routinely last for tens of seconds, which are practically forever on quantum
mechanical time scales. Despite such infinite states of darkness, the dots
miraculously recover and start emitting again. Although the underlying
mechanism responsible for this phenomenon remains an enduring mystery and many
questions remain, we argue that substantial theoretical progress has been made.


title:
Comparison of structure and transport properties of concentrated hard
  and soft sphere fluids

abstract:
  Using Newtonian and Brownian dynamics simulations, the structural and
transport properties of hard and soft spheres have been studied. The soft
spheres were modeled using inverse power potentials ($V\sim r^{-n}$, with $1/n$
the potential softness). Although the pressure, diffusion coefficient and
viscosity depend at constant density on the particle softness up to extremely
high values of $n$, we show that scaling the density with the freezing point
for every system effectively collapses these parameters for $n\geq 18$
(including hard spheres), for large densities. At the freezing points, the long
range structure of all systems is identical, when the distance is measured in
units of the interparticle distance, but differences appear at short distances
(due to the different shape of the interaction potential). This translates into
differences at short times in the velocity and stress autocorrelation
functions, although they concur to give the same value of the corresponding
transport coefficient (for the same density to freezing ratio); the microscopic
dynamics also affects the short time behaviour of the correlation functions and
absolute values of the transport coefficients, but the same scaling with the
freezing density works for Newtonian or Brownian dynamics. For hard spheres,
the short time behaviour of the stress autocorrelation function has been
studied in detail, confirming quantitatively the theoretical forms derived for
it.


title:
Thermocapillary effects in driven dewetting and self-assembly of pulsed
  laser-irradiated metallic films

abstract:
  In this paper the lubrication-type dynamical model is developed of a molten,
pulsed laser-irradiated metallic film. The heat transfer problem that
incorporates the absorbed heat from a single beam or interfering beams is
solved analytically. Using this temperature field, we derive the 3D long-wave
evolution PDE for the film height. To get insights into dynamics of dewetting,
we study the 2D version of the evolution equation by means of a linear
stability analysis and by numerical simulations. The stabilizing and
destabilizing effects of various system parameters, such as the peak laser beam
intensity, the film optical thickness, the Biot and Marangoni numbers, etc. are
elucidated. It is observed that the film stability is promoted for such
parameters variations that increase the heat production in the film. In the
numerical simulations the impacts of different irradiation modes are
investigated. In particular, we obtain that in the interference heating mode
the spatially periodic irradiation results in a spatially periodic film rupture
with the same, or nearly equal period. The 2D model qualitatively reproduces
the results of the experimental observations of a film stability and spatial
ordering of a re-solidified nanostructures.


title: Optical identification of hard X-ray source IGRJ18257-0707

abstract:
  We present the results of the optical identification of hard X-ray source
IGRJ18257-0707 trough the spectroscopic observations of its optical counterpart
with RTT150 telescope. Accurate position of the X-ray source, determined using
Chandra observations, allowed us to associate this source with the faint
optical object (m_R=~20.4), which shows broad H_\alpha emission line in its
optical spectrum. Therefore we conclude that the source IGRJ18257-0707 is a
type 1 Seyfert galaxy at redshift z=0.037.


title: The Impact of Mobility on Gossip Algorithms

abstract:
  The influence of node mobility on the convergence time of averaging gossip
algorithms in networks is studied. It is shown that a small number of fully
mobile nodes can yield a significant decrease in convergence time. A method is
developed for deriving lower bounds on the convergence time by merging nodes
according to their mobility pattern. This method is used to show that if the
agents have one-dimensional mobility in the same direction the convergence time
is improved by at most a constant. Upper bounds are obtained on the convergence
time using techniques from the theory of Markov chains and show that simple
models of mobility can dramatically accelerate gossip as long as the mobility
paths significantly overlap. Simulations verify that different mobility
patterns can have significantly different effects on the convergence of
distributed algorithms.


title:
Uniqueness of self-similar solutions to the network flow in a given
  topological class

abstract:
  In this paper we study the uniqueness of expanding self-similar solutions to
the network flow in a fixed topological class. We prove the result via the
parabolic Allen-Cahn approximation proved in \cite{triodginz}.
  Moreover, we prove that any regular evolution of connected tree-like network
(with an initial condition that might be not regular) is unique in a given a
topological class.


title: Dichotomy in the Dynamical Status of Massive Cores in Orion

abstract:
  To study the evolution of high mass cores, we have searched for evidence of
collapse motions in a large sample of starless cores in the Orion molecular
cloud. We used the Caltech Submillimeter Observatory telescope to obtain
spectra of the optically thin (\H13CO+) and optically thick (\HCO+) high
density tracer molecules in 27 cores with masses $>$ 1 \Ms. The red- and
blue-asymmetries seen in the line profiles of the optically thick line with
respect to the optically thin line indicate that 2/3 of these cores are not
static. We detect evidence for infall (inward motions) in 9 cores and outward
motions for 10 cores, suggesting a dichotomy in the kinematic state of the
non-static cores in this sample. Our results provide an important observational
constraint on the fraction of collapsing (inward motions) versus non-collapsing
(re-expanding) cores for comparison with model simulations.


title:
Absolutely Continuous Spectrum for the Anderson Model on Some Tree-like
  Graphs

abstract:
  We prove persistence of absolutely continuous spectrum for the Anderson model
on a general class of tree-like graphs.


title: Multirate integration of axisymmetric step-flow equations

abstract:
  We present a multirate method that is particularly suited for integrating the
systems of Ordinary Differential Equations (ODEs) that arise in step models of
surface evolution. The surface of a crystal lattice, that is slightly miscut
from a plane of symmetry, consists of a series of terraces separated by steps.
Under the assumption of axisymmetry, the step radii satisfy a system of ODEs
that reflects the steps' response to step line tension and step-step
interactions. Two main problems arise in the numerical solution of these
equations. First, the trajectory of the innermost step can become singular,
resulting in a divergent step velocity. Second, when a step bunching
instability arises, the motion of steps within a bunch becomes very strongly
stable, resulting in "local stiffness". The multirate method introduced in this
paper ensures that small time steps are taken for singular and locally stiff
components, while larger time steps are taken for the remaining ones. Special
consideration is given to the construction of high order interpolants during
run time which ensures fourth order accuracy of scheme for components of the
solution sufficiently far away from singular trajectories.


title: Obscured and powerful AGN and starburst activities at z~3.5

abstract:
  We report the discovery of two sources at z=3.867 and z=3.427 that exhibit
powerful starburst and AGN activities. They benefit from data from radio to X
rays from the CFHTLS-D1/SWIRE/XMDS surveys. Follow-up optical and near-infrared
spectroscopy, and millimeter IRAM/MAMBO observations are also available. We
performed an analysis of their spectral energy distributions to understand the
origin of their emission and constrain their luminosities. A comparison with
other composite systems at similar redshifts from the literature is also
presented. The AGN and starburst bolometric luminosities are ~10^13 Lsun. The
AGN emission dominates at X ray, optical, mid-infrared wavelengths, and
probably in the radio. The starburst emission dominates in the far-infrared.
The estimated star formation rates range from 500 to 3000Msun/yr. The AGN
near-infrared and X ray emissions are heavily obscured in both sources with an
estimated dust extinction Av>4, and Compton-thick gas column densities. The two
sources are the most obscured and most luminous AGNs detected at millimeter
wavelengths currently known. The sources presented in this work are heavily
obscured QSOs, but their properties are not fully explained by the standard AGN
unification model. In one source, the ultraviolet and optical spectra suggest
the presence of outflowing gas and shocks, and both sources show emission from
hot dust, most likely in the vicinity of the nucleus. Evidence of moderate
AGN-driven radio activity is found in both sources. The two sources lie on the
local M_BH-M_bulge relation. To remain on this relation, their star formation
rate has to decrease. Our results support evolutionary models that invoke radio
feedback as star formation quenching mechanism, and suggest that such a
mechanism might play a major role also in powerful AGNs.


title: Diffractive and Exclusive Production at the Tevatron

abstract:
  We report new results from CDF on single-diffractive dijet and W/Z
production, and on exclusive dijet, diphoton, and dilepton production in
proton-antiproton collisions at sqrt{s}=1.96 TeV at the Fermilab Tevatron. The
measured exclusive dijet and diphoton cross sections provide a test of
theoretical predictions for exclusive Higgs production at the LHC.


title: Hadronic Fluctuations and Correlations

abstract:
  We will provide a review of some of the physics which can be addressed by
studying fluctuations and correlations in heavy ion collisions. We will discuss
Lattice QCD results on fluctuations and correlations and will put them into
context with observables which have been measured in heavy-ion collisions.
Special attention will be given to the QCD critical point and the first order
co-existence region, and we will discuss how the measurement of fluctuations
and correlations can help in an experimental search for non-trivial structures
in the QCD phase diagram.


title:
Asymptotic behavior of a nonlocal parabolic problem in Ohmic heating
  process

abstract:
  In this paper, we consider the asymptotic behavior of the nonlocal parabolic
problem \[ u_{t}=\Delta u+\displaystyle\frac{\lambda
f(u)}{\big(\int_{\Omega}f(u)dx\big)^{p}}, x\in \Omega, t>0, \] with homogeneous
Dirichlet boundary condition, where $\lambda>0, p>0$, $f$ is nonincreasing. It
is found that: (a) For $0<p\leq1$, $u(x,t)$ is globally bounded and the unique
stationary solution is globally asymptotically stable for any $\lambda>0$; (b)
For $1<p<2$, $u(x,t)$ is globally bounded for any $\lambda>0$; (c) For $p=2$,
if $0<\lambda<2|\partial\Omega|^2$, then $u(x,t)$ is globally bounded, if
$\lambda=2|\partial\Omega|^2$, there is no stationary solution and $u(x,t)$ is
a global solution and $u(x,t)\to\infty$ as $t\to\infty$ for all $x\in\Omega$,
if $\lambda>2|\partial\Omega|^2$, there is no stationary solution and $u(x,t)$
blows up in finite time for all $x\in\Omega$; (d) For $p>2$, there exists a
$\lambda^*>0$ such that for $\lambda>\lambda^*$, or for
$0<\lambda\leq\lambda^*$ and $u_0(x)$ sufficiently large, $u(x,t)$ blows up in
finite time. Moreover, some formal asymptotic estimates for the behavior of
$u(x,t)$ as it blows up are obtained for $p\geq2$.


title:
Constraints to Energy Spectra of Blazars based on Recent EBL Limits from
  Galaxy Counts

abstract:
  We combine the recent estimate of the contribution of galaxies to the 3.6
micron intensity of the extragalactic background light (EBL) with optical and
near-infrared (IR) galaxy counts to set new limits on intrinsic spectra of some
of the most distant TeV blazars 1ES 0229+200, 1ES 1218+30.4, and 1ES 1101-232,
located at redshifts 0.1396, 0.182, and 0.186, respectively. The new lower
limit on the 3.6 micron EBL intensity is significantly higher than the previous
one set by the cumulative emission from resolved Spitzer galaxies. Correcting
for attenuation by the revised EBL, we show that the differential spectral
index of the intrinsic spectrum of the three blazars is 1.28 +- 0.20 or harder.
These results present blazar emission models with the challenge of producing
extremely hard intrinsic spectra in the sub-TeV to multi-TeV regime. These
results also question the reliability of recently derived upper limits on the
near-IR EBL intensity that are solely based on the assumption that intrinsic
blazar spectra should not be harder than 1.5.


title: Optical absorption and emission of a quantum dot in the Kondo regime

abstract:
  A variant of the Anderson model, that describes hybridization between
localized state (c-state) of a quantum dot and a Fermi sea conduction band, is
investigated. We demonstrate that, as a function of the hybridization parameter
v, the system undergoes a crossover from the state where the conduction band
and the c-level are fully coupled to a state where these are decoupled. The
c-electron spectrum, however, has a gap together with the presence of the Kondo
peak in the former state. For the latter, we have a Mott-like localization
where the c-electron spectrum again has a gap without the Kondo peak. Within
this gap the conduction electrons fully recover the free band density of states
and the effective hybridization is practically zero. Our main aim, however, is
to study the emission and absorption in a quantum dot with strongly correlated
Kondo ground state. We use the Green function equation of motion method for
this purpose. We calculate the absorption/emission (A/E) spectrum in the Kondo
regime through a symmetrized quantum autocorrelation function obtainable
directly within perturbation theory using the Fermi golden rule approximation.
The spectrum reveals a sharp, tall peak close to Kondo-Abrikosov-Suhl peak and
a few smaller, distinguishable ones on either side. The former clearly
indicates that the Kondo phenomenon has its impact on A/E (non-Kondo
processes), which are driven by the coupling involving the dipole moment of
quantum dot transitions reflecting the physical structure of the dot including
the confinement potential, in the Kondo regime.


title: Channel-Optimized Quantum Error Correction

abstract:
  We develop a theory for finding quantum error correction (QEC) procedures
which are optimized for given noise channels. Our theory accounts for
uncertainties in the noise channel, against which our QEC procedures are
robust. We demonstrate via numerical examples that our optimized QEC procedures
always achieve a higher channel fidelity than the standard error correction
method, which is agnostic about the specifics of the channel. This demonstrates
the importance of channel characterization before QEC procedures are applied.
Our main novel finding is that in the setting of a known noise channel the
recovery ancillas are redundant for optimized quantum error correction. We show
this using a general rank minimization heuristic and supporting numerical
calculations. Therefore, one can further improve the fidelity by utilizing all
the available ancillas in the encoding block.


title: Viscoelastic Behavior of Solid $^4$He

abstract:
  Over the last five years several experimental groups have reported anomalies
in the temperature dependence of the period and amplitude of a torsional
oscillator containing solid $^4$He. We model these experiments by assuming that
$^4$He is a viscoelastic solid--a solid with frequency dependent internal
friction. We find that while our model can provide a quantitative account of
the dissipation observed in the torsional oscillator experiments, it only
accounts for about 10% of the observed period shift, leaving open the
possibility that the remaining period shift is due to the onset of
superfluidity in the sample.


title: Infrared behavior of QCD from the Dyson-Schwinger formalism

abstract:
  We discuss the properties of two different types of infrared solutions of
Landau gauge Yang-Mills theory and argue for one of these (the 'scaling
solution'). We furthermore clarify the status of previously obtained results
from DSEs on a four-torus. Including quarks we discuss a relation between
confinement and dynamical chiral symmetry breaking based on the scaling
solution of Yang-Mills theory. An infrared singularity in the quark-gluon
vertex allows for a solution of the $U_A$(1) problem along the lines of a
mechanism suggested by Kogut and Susskind long ago.


title:
The dispersion-managed Ginzburg-Landau equation and its application to
  femtosecond lasers

abstract:
  The complex Ginzburg-Landau equation has been used extensively to describe
various non-equilibrium phenomena. In the context of lasers, it models the
dynamics of a pulse by averaging over the effects that take place inside the
cavity. Ti:sapphire femtosecond lasers, however, produce pulses that undergo
significant changes in different parts of the cavity during each round-trip.
The dynamics of such pulses is therefore not adequately described by an average
model that does not take such changes into account. The purpose of this work is
severalfold. First we introduce the dispersion-managed Ginzburg-Landau equation
(DMGLE) as an average model that describes the long-term dynamics of systems
characterized by rapid variations of dispersion, nonlinearity and gain in a
general setting, and we study the properties of the equation. We then explain
how in particular the DMGLE arises for Ti:sapphire femtosecond lasers and we
characterize its solutions. In particular, we show that, for moderate values of
the gain/loss parameters, the solutions of the DMGLE are well approximated by
those of the dispersion-managed nonlinear Schrodinger equation (DMNLSE), and
the main effect of gain and loss dynamics is simply to select one among the
one-parameter family of solutions of the DMNLSE.


title: Parameterizing density matrices for composite quantum systems

abstract:
  A parametrization of density operators for bipartite quantum systems is
proposed. It is based on the particular parametrization of the unitary group
found recently by Jarlskog. It is expected that this parametrization will find
interesting applications in the study of quantum properties of many partite
systems.


title: On the Throughput Maximization in Dencentralized Wireless Networks

abstract:
  A distributed single-hop wireless network with $K$ links is considered, where
the links are partitioned into a fixed number ($M$) of clusters each operating
in a subchannel with bandwidth $\frac{W}{M}$. The subchannels are assumed to be
orthogonal to each other. A general shadow-fading model, described by
parameters $(\alpha,\varpi)$, is considered where $\alpha$ denotes the
probability of shadowing and $\varpi$ ($\varpi \leq 1$) represents the average
cross-link gains. The main goal of this paper is to find the maximum network
throughput in the asymptotic regime of $K \to \infty$, which is achieved by: i)
proposing a distributed and non-iterative power allocation strategy, where the
objective of each user is to maximize its best estimate (based on its local
information, i.e., direct channel gain) of the average network throughput, and
ii) choosing the optimum value for $M$. In the first part of the paper, the
network hroughput is defined as the \textit{average sum-rate} of the network,
which is shown to scale as $\Theta (\log K)$. Moreover, it is proved that in
the strong interference scenario, the optimum power allocation strategy for
each user is a threshold-based on-off scheme. In the second part, the network
throughput is defined as the \textit{guaranteed sum-rate}, when the outage
probability approaches zero. In this scenario, it is demonstrated that the
on-off power allocation scheme maximizes the throughput, which scales as
$\frac{W}{\alpha \varpi} \log K$. Moreover, the optimum spectrum sharing for
maximizing the average sum-rate and the guaranteed sum-rate is achieved at M=1.