title: Do local analogs of Lyman Break Galaxies exist?

abstract:
  The optical properties of a number of supercompact ultraviolet luminous
galaxies (UVLG), recently discovered in the local Universe matching GALEX and
Sloan Digital Sky Survey (SDSS) data, are discussed. Detailed re-analysis of
the SDSS data for these and other similar but nearer galaxies shows that their
surface brightness radial profile in both R and u bands is in most cases well
described by an extended disk plus a central unresolved component (possibly a
bulge). Since the SDSS pipeline used a single disk component to derive the half
light radius of these UVLGs their size was severely underestimated.
Consequently, the average UV surface brightness is much lower that previously
quoted casting doubts on the claim that UVLGs are the local analogs of high
redshift Lyman break galaxies.


title: AGN effect on cooling flow dynamics

abstract:
  We analyzed the feedback of AGN jets on cooling flow clusters using
three-dimensional AMR hydrodynamic simulations. We studied the interaction of
the jet with the intracluster medium and creation of low X-ray emission
cavities (Bubbles) in cluster plasma. The distribution of energy input by the
jet into the system was quantified in its different forms, i.e. internal,
kinetic and potential. We find that the energy associated with the bubbles, (pV
+ gamma pV/(gamma-1)), accounts for less than 10 percent of the jet energy.


title: Electron Bunching in Stacks of Coupled Quantum Dots

abstract:
  We study the transport properties of two double quantum dots in a parallel
arrangement at temperatures of a few Kelvin. Thereby, we show that decoherence
entailed by the substrate phonons affects the shot noise. For asymmetric
coupling between the dots and the respective lead, the current noise is
sub-Poissonian for resonant tunneling, but super-Poissonian in the vicinity of
the resonances. Our results indicate that phonon emission and absorption is
responsible for the shot noise enhancement. The observed asymmetry of the peaks
at low temperatures stems from spontaneous emission.


title:
Collinear versus non-collinear magnetic order in Pd atomic clusters:
  ab-initio calculations

abstract:
  We present a thorough theoretical assessment of the stability of
non-collinear spin arrangements in small palladium clusters. We generally find
that ferromagnetic order is always preferred, but that antiferromagnetic and
non-collinear configurations of different sorts exist and compete for the first
excited isomers. We also show that the ground state is insensitive to the
choice of atomic configuration for the pseudopotential used and to the
approximation taken for the exchange and correlation potential. Moreover, the
existence and relative stability of the different excited configurations also
depends weakly on the approximations employed. These results provide strong
evidence on the transferability of pseudopotential and exchange and correlation
functionals for palladium clusters as opposed to the situation found for the
bulk phases of palladium.


title:
Mass distributions for nuclear disintegration from fission to
  evaporation

abstract:
  By a proper choice of the excitation energy per nucleon we analyze the mass
distributions of the nuclear fragmentation at various excitation energies.
Starting from low energies (between 0.1 and 1 MeV/nucleon) up to higher
energies about 12 MeV/n, we classified the mass yield characteristics for heavy
nuclei (A>200) on the basis of Statistical Multifragmentation Model. The
evaluation of fragment distribution with the excitation energy show that the
present results exhibit the same trend as the experimental ones.


title: Running of $\alpha_s$ and $m_b$ in the MSSM

abstract:
  A consistent evolution of the strong coupling constant $\alpha_s$ from $M_Z$
to the GUT scale is presented, involving three-loop running and two-loop
decoupling. The two-loop transition from the MS- to the DR-scheme is properly
taken into account. In the second part of the paper, the bottom quark mass in
the DR-scheme at the electroweak/SUSY scale is evaluated with four-loop
accuracy. We find that the three-loop effects are comparable to the
experimental uncertainty both for $\alpha_s$ and $m_b$.


title: Ergodicity properties of quantum expectation values in entangled states

abstract:
  Using a model Hamiltonian for a single-mode electromagnetic field interacting
with a nonlinear medium, we show that quantum expectation values of subsystem
observables can exhibit remarkably diverse ergodic properties even when the
dynamics of the total system is regular. The time series of the mean photon
number is studied over a range of values of the ratio of the strength $\gamma$
of the nonlinearity to that of the inter-mode coupling $g$. We obtain the power
spectrum, estimate the embedding dimension of the reconstructed phase space and
the maximal Liapunov exponent $\lambda_{\rm max}$, and find the recurrence-time
distribution of the coarse-grained dynamics. The dynamical behavior ranges from
quasiperiodicity (for $\gamma/g \ll 1$) to chaos as characterized by
$\lambda_{\rm max} > 0$ (for $\gamma/g \gtrsim 1$), and is interpreted.


title: Thue equations and torsion groups of elliptic curves

abstract:
  A new characterization of rational torsion subgroups of elliptic curves is
found, for points of order greater than 4, through the existence of solution
for systems of Thue equations.


title:
Density-dependent interactions and structure of charged colloidal
  dispersions in the weak screening regime

abstract:
  We determine the structure of charge-stabilized colloidal suspensions at low
ionic strength over an extended range of particle volume fractions using a
combination of light and small angle neutron scattering experiments. The
variation of the structure factor with concentration is analyzed within a
one-component model of a colloidal suspension. We show that the observed
structural behavior corresponds to a non-monotonic density dependence of the
colloid effective charge and the mean interparticle interaction energy. Our
findings are corroborated by similar observations from primitive model computer
simulations of salt-free colloidal suspensions.


title:
Reply to Comment on "A local realist model for correlations of the
  singlet state"

abstract:
  The general conclusion of Seevinck and Larsson is that our model exploits the
so-called coincidence-time loophole and produces sinusoidal (quantum-like)
correlations but does not model the singlet state because it does not violate
the relevant Bell inequality derived by Larsson and Gill, since in order to
obtain the sinusoidal correlations the probability of coincidences in our model
goes to zero. In this reply, we refute their arguments that lead to this
conclusion and demonstrate that our model can reproduce results of photon and
ion-trap experiments with frequencies of coincidences that are not in conflict
with the observations.


title: On the shadow boundary of a centrally symmetric convex body

abstract:
  We discuss the concept of the shadow boundary of a centrally symmetric convex
ball $K$ (actually being the unit ball of a Minkowski normed space) with
respect to a direction ${\bf x}$ of the Euclidean n-space $R^n$. We introduce
the concept of general parameter spheres of $K$ corresponding to this direction
and prove that the shadow boundary is a topological manifold if all of the
non-degenerated general parameter spheres are, too. In this case, using the
approximation theorem of cell-like maps we get that they are homeomorphic to
the $(n-2)$-dimensional sphere $S^{(n-2)}$. We also prove that the bisector
(equidistant set of the corresponding normed space) in the direction ${\bf x}$
is homeomorphic to $R^{(n-1)}$ iff all of the non-degenerated general parameter
spheres are $(n-2)$-manifolds implying that if the bisector is a homeomorphic
copy of $R^{(n-1)}$ then the corresponding shadow boundary is a topological
$(n-2)$-sphere.


title: The variability plane of accreting compact objects

abstract:
  Recently, it has been shown that soft-state black hole X-ray binaries and
active galactic nuclei populate a plane in the space defined by the black hole
mass, accretion rate and characteristic frequency. We show that this plane can
be extended to hard-state objects if one allows a constant offset for the
frequencies in the soft and the hard state. During a state transition the
frequencies rapidly move from one scaling to the other depending on an
additional parameter, possibly the disk-fraction. The relationship between
frequency, mass and accretion rate can be further extended by including weakly
accreting neutron stars. We explore if the lower kHz QPOs of neutron stars and
the dwarf nova oscillations of white dwarfs can be included as well and discuss
the physical implications of the found correlation.


title:
Constraints on top-down models for the origin of UHECRs from the Pierre
  Auger Observatory data

abstract:
  Taking into account the Pierre Auger Observatory limits on the photon
fraction among the highest energy cosmic rays, we show that the models based on
the decay of super-heavy dark matter in the halo of our Galaxy are essentially
excluded from being the sources of UHECRs unless their contribution becomes
significant only above 100 EeV. Some top-down models based on topological
defects are however compatible with the current data and may be best
constrained in the future by the high-energy neutrino flux limit.


title:
Structure of glassy lithium sulfate films sputtered in nitrogen (LISON):
  Insight from Raman spectroscopy and ab initio calculations

abstract:
  Raman spectra of thin solid electrolyte films obtained by sputtering a
lithium sulfate target in nitrogen plasma are measured and compared to ab
initio electronic structure calculations for clusters composed of 28 atoms.
Agreement between measured and calculated spectra is obtained when oxygen atoms
are replaced by nitrogen atoms and when the nitrogen atoms form bonds with each
other. This suggests that the incorporation of nitrogen during the sputtering
process leads to structures in the film, which prevent crystallization of these
thin film salt glasses.


title: Variable stars in the open cluster NGC 6791 and its surrounding field

abstract:
  Aims: This work presents a high--precision variability survey in the field of
the old, super metal-rich open cluster NGC 6791.
  Methods: The data sample consists of more than 75,000 high-precision CCD time
series measurements in the V band obtained mainly at the Canada-France-Hawaii
Telescope, with additional data from S. Pedro Martir and Loiano observatories,
over a time span of ten nights. The field covers an area of 42x28 arcmin^2.
  Results: We have discovered 260 new variables and re-determined periods and
amplitudes of 70 known variable stars. By means of a photometric evaluation of
the membership in NGC 6791, and a preliminary membership based on the proper
motions, we give a full description of the variable content of the cluster and
surrounding field in the range 16<V<23.5. Accurate periods can be given for the
variables with P<4.0 d, while for ones with longer periods the limited
time-baseline hampered precise determinations. We categorized the entire sample
as follows: 6 pulsating, 3 irregular, 3 cataclysmic, 89 rotational variables
and 61 eclipsing systems; moreover, we detected 168 candidate variables for
which we cannot give a variability class since their periods are much longer
than our time baseline.
  Conclusions: On the basis of photometric considerations, and of the positions
of the stars with respect to the center of the cluster, we inferred that 11 new
variable stars are likely members of the cluster, for 22 stars the membership
is doubtful and 137 are likely non-members. We also detected an outburst of
about 3 mag in the light curve of a very faint blue star belonging to the
cluster and we suggest that this star could be a new U Gem (dwarf nova)
cataclysmic variable.


title:
Outage Behavior of Discrete Memoryless Channels Under Channel Estimation
  Errors

abstract:
  Classically, communication systems are designed assuming perfect channel
state information at the receiver and/or transmitter. However, in many
practical situations, only an estimate of the channel is available that differs
from the true channel. We address this channel mismatch scenario by using the
notion of estimation-induced outage capacity, for which we provide an
associated coding theorem and its strong converse, assuming a discrete
memoryless channel. We illustrate our ideas via numerical simulations for
transmissions over Ricean fading channels under a quality of service (QoS)
constraint using rate-limited feedback channel and maximum likelihood (ML)
channel estimation. Our results provide intuitive insights on the impact of the
channel estimate and the channel characteristics (SNR, Ricean K-factor,
training sequence length, feedback rate, etc.) on the mean outage capacity.


title: Local models and EPR quantum correlations

abstract:
  A model for two entangled systems in an EPR setting is shown to reproduce the
quantum-mechanical outcomes and expectation values. Each system is represented
by a small sphere containing a point-like particle embedded in a field. A
quantum state appears as an equivalence class of several possible
particle-field configurations. Contrarily to Bell-type hidden variables models,
the fields account for the non-commutative aspects of the measurements and deny
the simultaneous reality of incompatible physical quantities, thereby allowing
to escape EPR's ``completeness or locality'' dilemma.


title: The two Josephson junction flux qubit with large tunneling amplitude

abstract:
  In this paper we discuss solid-state nanoelectronic realizations of Josephson
flux qubits with large tunneling amplitude between the two macroscopic states.
The latter can be controlled via the height and wells form of the potential
barrier, which is determined by quantum-state engineering of the flux qubit
circuit. The simplest circuit of the flux qubit is a superconducting loop
interrupted by a Josephson nanoscale tunnel junction. The tunneling amplitude
between two macroscopically different states can be essentially increased, by
engineering of the qubit circuit, if tunnel junction is replaced by a ScS
contact. However, only Josephson tunnel junctions are particularly suitable for
large-scale integration circuits and quantum detectors with preset-day
technology. To overcome this difficulty we consider here the flux qubit with
high-level energy separation between "ground" and "excited" states, which
consists of a superconducting loop with two low-capacitance Josephson tunnel
junctions in series. We demonstrate that for real parameters of resonant
superposition between the two macroscopic states the tunneling amplitude can
reach values greater than 1K. Analytical results for the tunneling amplitude
obtained within semiclassical approximation by instanton technique show good
correlation with a numerical solution.


title: Surface melting of nanoscopic epitaxial films

abstract:
  By introducing finite size surface and interfacial excess quantities,
interactions between interfaces are shown to modify the usual surface
premelting phenomenon. It is the case of surface melting of a thin solid film s
deposited on a planar solid substrate S. More precisely to the usual wetting
condition of the solid s by its own melt l, necessary for premelting (wetting
factor F<0), is adjoined a new quantity G describing the interactions of the
l/s interface with the s/S interface. When G>0 this interface attraction boosts
the premelting so that a two stage boosted surface premelting is foreseen: a
continuous premelting, up to roughly half the deposited film, is followed by an
abrupt first order premelting. When G<0 these interfaces repell each other so
that premelting is refrained and the film remains partly solid above the bulk
melting point (overheating) what is called astride melting. Elastic stress
modifies both types of melting curves. Bulk and surface stresses have to be
distinguished.


title: Terahertz Parametric Gain in Semiconductor Superlattices

abstract:
  We consider a high-frequency response of electrons in a single miniband of
superlattice subject to dc and ac electric fields. Action of ac electric field
causes oscillations of electron's effective mass in miniband, which result in a
parametric resonance. We have established a theoretical feasibility of
phase-sensitive parametric amplification at the resonance. The parametric
amplification does not require operation in conditions of negative differential
conductance. Therefore a formation of destructive domains of high electric
field inside the superlattice can be prevented. Here we concentrate on the
parametric up- and down-conversion of electromagnetic radiation from available
frequencies to desirable THz frequency range.


title: Random resistor network model of minimal conductivity in graphene

abstract:
  Transport in undoped graphene is related to percolating current patterns in
the networks of {\em N-} and {\em P}-type regions reflecting the strong bipolar
charge density fluctuations. Transmissions of the {\em P-N} junctions, though
small, are vital in establishing the macroscopic conductivity. We propose a
random resistor network model to analyze scaling dependencies of the
conductance on the doping and disorder, the quantum magnetoresistance and the
corresponding dephasing rate.


title: Optical spectroscopy of RU Cam, a pulsating carbon star

abstract:
  We analysed the high resolution spectra of a RU Cam, classified as W Vir type
star. The atmospheric parameters of RU Cam were estimated Teff=5250K and log
g=1.0. The hydrogen deficiency of RU Cam was not confirmed. The iron abundance,
[Fe/H]=-0.37, is close to the solar one. Abundances of most other elements are
also close to normal. We found considerable excesses of carbon and nitrogen:
[C/Fe]=+0.98, [N/Fe]=+0.60. The carbon to oxygen ratio is C/O$\ge$1. The carbon
isotopic abundance ratio is equal to C^12/C^13=4.5. For sodium a moderate
overabundance Na/Fe=+0.55 was obtained. For two moments of observations we
found close heliocentric velocity values, Vr=-21.7+/-0.8 and -23.1+/-1.0 km/s.
Both spectra contain a peculiar feature - an emission component of NaI doublet
which location agrees with the radial velocity from the bulk of metallic lines.
For our two observing moments we found no dependence of radial velocities on
the formation depth or on excitation energy for metallic lines.


title: On Scattering for CMV Matrices

abstract:
  Adamjan-Arov (Lax--Phillips) model space is considered as a scattering
representation space for a CMV matrix in context of an extended
Marchenko--Faddeev scattering theory. That is, there exists a basis in which
the multiplication by independent variable is a CMV matrix. This basis as well
as Verblunski coefficients are computed explicitly in terms of Nehari
interpolation. Asymptotically the Verblynski coefficients go to zero. Moreover,
relations between the basis and wandering subspaces are established.
Transformation from scattering representation to spectral representation is
given.


title: Entropy profiles in X-ray luminous galaxy clusters at z>0.1

abstract:
  [Abridged] The entropy distribution of the intracluster gas reflects both
accretion history of the gas and processes of feedback which provide a further
non-gravitational energy besides the potential one. In this work, we study the
profiles and the scaling properties of the gas entropy in 24 hot (kT_{gas} > 6
keV) galaxy clusters observed with Chandra in the redshift range 0.14-0.82 and
showing different states of relaxation. We recover the gas density, temperature
and entropy profiles in a non-parametric way. Adding the hydrostatic
equilibrium hypothesis, radial profiles are also obtained from the deprojection
of the surface brightness, allowing to verify whether the hydrostatic
equilibrium is a tenable hypothesis by comparison with the spectral
measurements. We confirm that this is the case on scales larger than 100 kpc
and discuss the deviations observed in few non-cooling core clusters in the
inner regions. We show that the entropy profiles are remarkably similar outside
the core and can be described by simple power-laws with slope of 1.0-1.2. We
measure an entropy level at 0.1 R_{200} of 100-500 keV cm^2 and a central
plateau which spans a wide range of value (~ a few-200 keV cm^2) depending on
the state of relaxation of the source. To characterize the energetic of the
central regions, we compare the radial behaviour of the temperature of the gas
with the temperature of the dark matter T_{DM} by estimating the excess of
energy Delta E = 3/2 k(T_{gas}- T_{DM}). We point out that Delta E ranges from
~ 0 in typical cooling-core clusters to few keV within 100 kpc in non-cooling
core systems. We also measure a significant correlation between the total iron
mass and the entropy outside the cooling region,whereas in the inner regions
they anti-correlate strongly.


title:
Electron-positron annihilation into phi f_{0}(980) and clues for a new
  1^{--} resonance

abstract:
  We study the e^{+}e^{-} to phi pi pi reaction for pions in an isoscalar
s-wave which is dominated by loop mechanisms. For kaon loops we start from the
conventional RCHPT, but use the unitarized amplitude for KbarK-pipi scattering
and the full kaon form factor instead of the lowest order terms. We study also
effects of vector mesons using RCHPT supplemented with the conventional
anomalous term for VVP interactions and taking into account the effects of
heavy vector mesons in the K*K transition form factor. We find a peak in the
dipion invariant mass around the f_{0}(980) as in the experiment. Selecting the
phi f_{0}(980) contribution as a function of the e^{+}e^{-} energy we also
reproduce the experimental data except for a narrow peak, yielding support to
the existence of a 1^{--} resonance above the phi f_{0}(980) threshold,
coupling strongly to this state.


title:
Nontrivial critical crossover between directed percolation models:
  Effect of infinitely many absorbing states

abstract:
  At non-equilibrium phase transitions into absorbing (trapped) states, it is
well known that the directed percolation (DP) critical scaling is shared by two
classes of models with a single (S) absorbing state and with infinitely many
(IM) absorbing states. We study the crossover behavior in one dimension,
arising from a considerable reduction of the number of absorbing states
(typically from the IM-type to the S-type DP models), by following two
different (excitatory or inhibitory) routes which make the auxiliary field
density abruptly jump at the crossover. Along the excitatory route, the system
becomes overly activated even for an infinitesimal perturbation and its
crossover becomes discontinuous. Along the inhibitory route, we find continuous
crossover with the universal crossover exponent $\phi\simeq 1.78(6)$, which is
argued to be equal to $\nu_\|$, the relaxation time exponent of the DP
universality class on a general footing. This conjecture is also confirmed in
the case of the directed Ising (parity-conserving) class. Finally, we discuss
the effect of diffusion to the IM-type models and suggest an argument why
diffusive models with some hybrid-type reactions should belong to the DP class.


title: Remote laboratories: new technology and standard based architecture

abstract:
  E-Laboratories are important components of e- learning environments,
especially in scientific and technical disciplines. First widespread E-Labs
consisted in proposing simulations of real systems (virtual labs), as building
remote labs (remote control of real systems) was difficult by lack of
industrial standards and common protocols. Nowadays, robotics and automation
technologies make easier the interfacing of systems with computers. In this
frame, many researchers (such as those mentioned in [1]) focus on how to set up
such a remote control. But, only a few of them deal with the educational point
of view of the problem. This paper outlines our current research and reflection
about remote laboratory modelling.


title: U_{PMNS} = U_ell^dagger U_nu

abstract:
  We consider corrections to vanishing U_{e3} and maximal atmospheric neutrino
mixing originating from the relation U = U_ell^dagger U_nu, where U is the PMNS
mixing matrix and U_ell (U_nu) is associated with the diagonalization of the
charged lepton (neutrino) mass matrix. We assume that in the limit of U_ell or
U_nu being the unit matrix, one has U_{e3} = 0 and theta_{23} = pi/4, while the
solar neutrino mixing angle is a free parameter. Well-known special cases of
the indicated scenario are the bimaximal and tri-bimaximal mixing schemes. If
U_{e3} \neq 0 and theta_{23} \neq pi/4 due to corrections from the charged
leptons, |U_{e3}| can be sizable (close to the existing upper limit) and we
find that the value of the solar neutrino mixing angle is linked to the
magnitude of CP violation in neutrino oscillations. In the alternative case of
the neutrino sector correcting U_{e3} = 0 and theta_{23} = pi/4, we obtain a
generically smaller |U_{e3}| than in the first case. Now the magnitude of CP
violation in neutrino oscillations is connected to the value of the atmospheric
neutrino mixing angle theta_{23}. We find that both cases are in agreement with
present observations. We also introduce parametrization independent "sum-rules"
for the oscillation parameters.


title: The Interaction Of Multiple Convection Zones In A-type Stars

abstract:
  A-type stars have a complex internal structure with the possibility of
multiple convection zones. If not sufficiently separated, such zones will
interact through the convectively stable regions that lie between them. It is
therefore of interest to ask whether the typical conditions that exist within
such stars are such that these convections zones can ever be considered as
disjoint.
  In this paper we present results from numerical simulations that help in
understanding how increasing the distance between the convectively unstable
regions are likely to interact through the stable region that separates them.
This has profound implications for mixing and transport within these stars.


title: Rational formality of function spaces

abstract:
  Let $X$ be a nilpotent space such that there exists $N\geq 1$ with
$H^N(X,\mathbb Q) \ne 0$ and $H^n(X,\mathbb Q)=0$ if $n>N$. Let $Y$ be a
m-connected space with $m\geq N+1$ and $H^*(Y,\mathbb Q)$ is finitely generated
as algebra. We assume that the odd part of the rational Hurewicz homomorphism:
$\pi_{odd}(X)\otimes \mathbb Q\to H_{odd}(X,\mathbb Q)$ is non-zero. We prove
that if the space $\mathcal F(X,Y)$ of continuous maps from $X$ to $Y$ is
rationally formal, then $Y$ has the rational homotopy type of a finite product
of Eilenberg Mac Lane spaces. At the opposite, we exhibit an example of a
rationally formal space $\mathcal F(S^2,Y)$ where $Y$ is not rationally
equivalent to a product of Eilenberg Mac Lane spaces.


title:
Quantum and semiclassical phase functions for the quantization of
  symmetric oscillators

abstract:
  We investigate symmetric oscillators, and in particular their quantization,
by employing semiclassical and quantum phase functions introduced in the
context of Liouville-Green transformations of the Schr\"{o}dinger equation. For
anharmonic oscillators, first order semiclassical quantization is seldom
accurate and the higher order expansions eventually break down given the
asymptotic nature of the series. A quantum phase that allows in principle to
retrieve the exact quantum mechanical quantization condition and wavefunctions
is given along with an iterative scheme to compute it. The arbitrariness
surrounding quantum phase functions is lifted by supplementing the phase with
boundary conditions involving high order semiclassical expansions. This allows
to extend the definition of oscillation numbers, that determine the
quantization of the harmonic oscillator, to the anharmonic case. Several
illustrations involving homogeneous as well as coupling constant dependant
anharmonic oscillators are given.


title:
Security problems with a SC-CNN-based Chaotic Masking Secure
  Communication System

abstract:
  This paper studies the security of a chaotic cryptosystem based on the Chua
circuit and implemented with State Controlled Cellular Neural Networks. It is
shown that the plaintext can be retrieved by ciphertext band-pass filtering
after an imperfect decoding with wrong receiver parameters. It is also shown
that the key space of the system can be notably reduced easing a brute force
attack. The system parameters were determined with high precision through the
analysis of the decoding error produced by the mismatch between receiver and
transmitter parameters.


title: Kinetics of cell division in epidermal maintenance

abstract:
  The rules governing cell division and differentiation are central to
understanding the mechanisms of development, aging and cancer. By utilising
inducible genetic labelling, recent studies have shown that the clonal
population in transgenic mouse epidermis can be tracked in vivo. Drawing on
these results, we explain how clonal fate data may be used to infer the rules
of cell division and differentiation underlying the maintenance of adult murine
tail-skin. We show that the rates of cell division and differentiation may be
evaluated by considering the long-time and short-time clone fate data, and that
the data is consistent with cells dividing independently rather than
synchronously. Motivated by these findings, we consider a mechanism for cancer
onset based closely on the model for normal adult skin. By analysing the
expected changes to clonal fate in cancer emerging from a simple two-stage
mutation, we propose that clonal fate data may provide a novel method for
studying the earliest stages of the disease.


title: Moduli space of Brody curves, energy and mean dimension

abstract:
  We study the mean dimension of the moduli space of Brody curves. We introduce
the notion of "mean energy" and show that this can be used to estimate the mean
dimension.


title: Dimensional Reduction applied to QCD at higher orders

abstract:
  Recent developments in higher order calculations within the framework of
Dimensional Reduction, the preferred regularization scheme for supersymmetric
theories, are reported on. Special emphasis is put on the treatment of
evanescent couplings, the equivalence to Dimensional Regularization, and the
evaluation of $\alpha_s(M_GUT)$ from $\alpha_s(M_Z)$.


title:
Real Forms of Complex Higher Spin Field Equations and New Exact
  Solutions

abstract:
  We formulate four dimensional higher spin gauge theories in spacetimes with
signature (4-p,p) and nonvanishing cosmological constant. Among them are chiral
models in Euclidean (4,0) and Kleinian (2,2) signature involving half-flat
gauge fields. Apart from the maximally symmetric solutions, including de Sitter
spacetime, we find: (a) SO(4-p,p) invariant deformations, depending on a
continuous and infinitely many discrete parameters, including a degenerate
metric of rank one; (b) non-maximally symmetric solutions with vanishing Weyl
tensors and higher spin gauge fields, that differ from the maximally symmetric
solutions in the auxiliary field sector; and (c) solutions of the chiral models
furnishing higher spin generalizations of Type D gravitational instantons, with
an infinite tower of Weyl tensors proportional to totally symmetric products of
two principal spinors. These are apparently the first exact 4D solutions with
non-vanishing massless higher spin fields.


title:
QED collinear radiation factors in the next-to-leading logarithmic
  approximation

abstract:
  The effect of the collinear photon radiation by charged particles is
considered in the second order of the perturbation theory. Double and single
photon radiation is evaluated. The corresponding radiation factors are
obtained. The QED renormalization group approach is exploited in the
next-to-leading order. The results are suited to perform a systematic treatment
of the second order next-to-leading logarithmic radiative corrections to
various processes either analytically or numerically.


title:
Characterization of an asynchronous source of heralded single photons
  generated at a wavelength of 1550 nm

abstract:
  We make a thorough analysis of heralded single photon sources regarding how
factors such as the detector gate-period, the photon rates, the fiber coupling
efficiencies, and the system losses affect the performance of the source. In
the course of this we give a detailed description of how to determine fiber
coupling efficiencies from experimentally measurable quantities. We show that
asynchronous sources perform, under most conditions, better than synchronous
sources with respect to multiphoton events, but only for nearly perfect
coupling efficiencies. We apply the theory to an asynchronous source of
heralded single photons based on spontaneous parametric downconversion in a
periodically poled, bulk, KTiOPO4 crystal. The source generates light with
highly non-degenerate wavelengths of 810 nm and 1550 nm, where the 810 nm
photons are used to announce the presence of the 1550 nm photons inside a
single-mode optical fiber. For our setup we find the probability of having a
1550 nm photon present in the single-mode fiber, as announced by the 810 nm
photon, to be 48%. The probability of multiphoton events is strongly suppressed
compared to a Poissonian light source, giving highly sub-Poisson photon
statistics.


title: Dark Matter and Dark Energy

abstract:
  This is a short review, aimed at a general audience, of several current
subjects of research in cosmology. The topics discussed include the cosmic
microwave background (CMB), with particular emphasis on its relevance for
testing inflation; dark matter, with a brief review of astrophysical evidence
and more emphasis on particle candidates; and cosmic acceleration and some of
the ideas that have been put forward to explain it. A glossary of technical
terms and acronyms is provided.


title: Explicit birational geometry of threefolds of general type

abstract:
  Let $V$ be a complex nonsingular projective 3-fold of general type. We prove
$P_{12}(V)>0$ and $P_{24}(V)>1$ (which answers an open problem of J. Kollar and
S. Mori). We also prove that the canonical volume has an universal lower bound
$\text{Vol}(V) \geq 1/2660$ and that the pluri-canonical map $\Phi_m$ is
birational onto its image for all $m\geq 77$. As an application of our method,
we prove Fletcher's conjecture on weighted hyper-surface 3-folds with terminal
quotient singularities. Another featured result is the optimal lower bound
$\text{Vol}(V)\geq {1/420}$ among all those 3-folds $V$ with $\chi({\mathcal
O}_V)\leq 1$.


title: Parton distribution functions and quark orbital motion

abstract:
  Covariant version of the quark-parton model is studied. Dependence of the
structure functions and parton distributions on the 3D quark intrinsic motion
is discussed. The important role of the quark orbital momentum, which is a
particular case of intrinsic motion, appears as a direct consequence of the
covariant description. Effect of orbital motion is substantial especially for
polarized structure functions. At the same time, the procedure for obtaining
the quark momentum distributions of polarized quarks from the combination of
polarized and unpolarized structure functions is suggested.


title:
Low-energy Dipole Excitations in Nuclei at the N=50,82 and Z=50 Shell
  Closures as Signatures for a Neutron Skin

abstract:
  Low-energy dipole excitations have been investigated theoretically in N=50,
several N=82 isotones and the Z=50 Sn isotopes. For this purpose a method
incorporating both HFB and multi-phonon QPM theory is applied. A concentration
of one-phonon dipole strength located below the neutron emission threshold has
been calculated in these nuclei. The analysis of the corresponding neutron and
proton dipole transition densities allows to assign a genuine pattern to the
low-energy excitations and making them distinct from the conventional GDR
modes. Analyzing also the QRPA wave functions of the states we can identify
these excitations as Pygmy Dipole Resonance (PDR) modes, recently studied also
in Sn and N=82 nuclei. The results for N=50 are exploratory for an experimental
project designed for the bremsstrahlung facility at the ELBE accelerator.


title: QCD dynamics at low x in ep collisions at HERA

abstract:
  Forward jet and multijet production has been measured at low Bjorken x at
HERA. The measured cross sections and correlations were compared to predictions
from DGLAP-based fixed-order calculations. Further comparisons were made to
DGLAP-based and CCFM-based leading-order Monte Carlo predictions, as well as to
Colour-Dipole model predictions. For the majority of the phase space covered in
the HERA kinematic region, fixed-order calculations describe the data well,
while the leading-order models provide an inconsistent description of the data.


title: Wave propagation in axion electrodynamics

abstract:
  In this paper, the axion contribution to the electromagnetic wave propagation
is studied. First we show how the axion electrodynamics model can be embedded
into a premetric formalism of Maxwell electrodynamics. In this formalism, the
axion field is not an arbitrary added Chern-Simon term of the Lagrangian, but
emerges in a natural way as an irreducible part of a general constitutive
tensor.We show that in order to represent the axion contribution to the wave
propagation it is necessary to go beyond the geometric approximation, which is
usually used in the premetric formalism. We derive a covariant dispersion
relation for the axion modified electrodynamics. The wave propagation in this
model is studied for an axion field with timelike, spacelike and null
derivative covectors. The birefringence effect emerges in all these classes as
a signal of Lorentz violation. This effect is however completely different from
the ordinary birefringence appearing in classical optics and in premetric
electrodynamics. The axion field does not simple double the ordinary light cone
structure. In fact, it modifies the global topological structure of light cones
surfaces. In CFJ-electrodynamics, such a modification results in violation of
causality. In addition, the optical metrics in axion electrodynamics are not
pseudo-Riemannian. In fact, for all types of the axion field, they are even
non-Finslerian.


title: Strong Lensing Analysis of the Cluster RCS0224-0002 at $z=0.77$

abstract:
  We present a detailed mass reconstruction of the cluster RCS0224-0002 at
$z=0.773$ from the strong lensing features observed with HST/WFPC2. The mass
profile is reconstructed using a parametric approach. We introduce a novel
method to fit extended multiple images based on the Modified Hausdorff Distance
between observed arcs and the arcs reproduced by the model. We perform the
detailed error analysis of the model parameter using the MCMC method. Our model
reproduces all the observed strong lensing features of the RCS0224-0002 and
predicts the redshift of one of the arcs systems to be $z\approx 2.65$ (the
other system has an spectroscopic redshift of $z=4.87$). The reconstructed
inner mass profile is well fitted by a non-singular isothermal sphere, rather
than with an NFW model. Dark matter substructure, derived from the light
distribution of the most luminous cluster members, is crucial for reproducing
the complexity of the quadrupole image system, which could not be achieved
otherwise. The reconstructed mass distribution closely follows the light,
however it is significantly shifted from the X-ray emission of the gas. The
mass of RCS0224-0002 derived from the lensing model, $\approx 2\times10^{14}
M_\odot$ is in a very good agreement with the one obtained from the X-ray
temperature measured with deep Chandra observations.


title: Sensitivity of the NEMO detector to galactic microquasars

abstract:
  We present the results of Monte Carlo simulation studies of the capability of
the proposed NEMO km$^3$ telescope to detect TeV muon neutrinos from Galactic
microquasars. In particular we determined the detector sensitivity to each
known microquasar, optimizing the event selection in order to reject the
atmospheric background. We also determined the expected number of source and
background events surviving the selection.


title:
The cluster galaxy luminosity function at $z=0.3$: a recent origin for
  the faint-end upturn ?

abstract:
  We derive deep luminosity functions (to $M_z=-15$) for galaxies in Abell 1835
($z=0.25$) and AC 114 ($z=0.31$) and compare these with the local $z'$
luminosity function for 69 clusters. The data show that the faint-end upturn,
the excess of galaxies above a single Schechter function at $M_z < -17$, does
not exist in the higher redshift clusters. This suggests that the faint-end
upturn galaxies have been created recently, by infall into clusters of
star-forming field populations or via tidal disruption of brighter objects.^M


title: Injectivity and Projectivity in Analysis and Topology

abstract:
  We give new proofs for many injectivity results in analysis that make more
careful use of the duality between unital abelian C*-algebras and compact
Hausdorff spaces. We then extend many of these results to incorporate group
actions. Our approach uses only elementary topological constructions and
eliminates the need for results from the theory of Boolean algebras and
AW*-algebras that were used in earlier proofs.


title: The forgotten monoid

abstract:
  We study properties of the forgotten monoid which appeared in work of Lascoux
and Schutzenberger and recently resurfaced in the construction of dual
equivalence graphs by Assaf. In particular, we provide an explicit
characterization of the forgotten classes in terms of inversion numbers and
show that there are n^2-3n+4 forgotten classes in the symmetric group S_n. Each
forgotten class contains a canonical element that can be characterized by
pattern avoidance. We also show that the sum of Gessel's quasi-symmetric
functions over a forgotten class is a 0-1 sum of ribbon-Schur functions.


title: Constraining the Two-Higgs-Doublet-Model parameter space

abstract:
  We confront the Two-Higgs-Doublet Model with a variety of experimental
constraints as well as theoretical consistency conditions. The most
constraining data are the \bar B\to X_s\gamma decay rate (at low values of
M_{H^\pm}), and \Delta\rho (at both low and high M_{H^\pm}). We also take into
account the B\bar B oscillation rate and R_b, or the width \Gamma(Z\to b\bar b)
(both of which restrict the model at low values of \tan\beta), and the
B^-\to\tau\nu_\tau decay rate, which restricts the model at high \tan\beta and
low M_{H^\pm}. Furthermore, the LEP2 non-discovery of a light, neutral Higgs
boson is considered, as well as the muon anomalous magnetic moment. Since
perturbative unitarity excludes high values of \tan\beta, the model turns out
to be very constrained. We outline the remaining allowed regions in the
\tan\beta-M_{H^\pm} plane for different values of the masses of the two
lightest neutral Higgs bosons, and describe some of their properties.


title: Conformal oxide coating of Carbon Nanotubes

abstract:
  The International Roadmap for Ferroelectric Memories requires
three-dimensional integration of high-dielectric materials onto metal
interconnects or bottom electrodes by 2010. We report the first integration of
high-dielectric oxide films onto carbon nanotube electrodes with an aim of
ultra-high integration density of FeRAMs (Tb/in2).


title: Searches in Photon and Jet States

abstract:
  We present recent results from the Collider Detector at Fermilab (CDF) and D0
experiments using data from proton-antiproton collisions with sqrt(s) = 1.96
TeV at Run II of the Fermilab Tevatron. New physics may appear in events with
high transverse momentum objects, including photons and quark or gluon jets.
The results described here are of signature-based searches and model-based
searches probing supersymmetry, leptoquarks, 4th generation quarks, and large
extra dimensions.


title:
Discovery of diffuse radio emission at the center of the most
  X-ray-luminous cluster RX J1347.5-1145

abstract:
  We report on new VLA radio observations of the distant cluster RX
J1347.5-1145, which is the most luminous in X-rays. We aim at investigating the
possible presence of diffuse and extended radio emission in this very peculiar
system which shows both a massive cooling flow and merging signatures. New low
resolution (~18 arcsec) VLA radio observations of this cluster are combined
with higher resolution (~2 arcsec) data available in the VLA archive. We
discover the presence of a diffuse and extended (~500 kpc) radio source
centered on the cluster, unrelated to the radio emission of the central AGN.
The properties of the radio source, in particular a) its occurrence at the
center of a massive cooling flow cluster, b) its total size comparable to that
of the cooling region, c) its agreement with the observational trend between
radio luminosity and cooling flow power, indicate that RX J1347.5-1145 hosts a
radio mini-halo. We suggest that the radio emission of this mini-halo, which is
the most distant object of its class discovered up to now, is due to electron
re-acceleration triggered by the central cooling flow. However, we also note
that the morphology of the diffuse radio emission shows an elongation
coincident with the position of a hot subclump detected in X-rays, thus
suggesting that additional energy for the electron re-acceleration might be
provided by the submerger event.


title:
Mass distribution in the most X-ray-luminous galaxy cluster RX
  J1347.5-1145 studied with XMM-Newton

abstract:
  We report on the analysis of XMM-Newton observations of RX J1347.5-1145
(z=0.451), the most X-ray-luminous galaxy cluster. We present a detailed total
and gas mass determination up to large distances (~1.7 Mpc), study the scaling
properties of the cluster, and explore the role of AGN heating in the cluster
cool core. By means of spatially resolved spectroscopy we derive density,
temperature, entropy, and cooling time profiles of the intra-cluster medium. We
compute the total mass profile of the cluster in the assumption of hydrostatic
equilibrium. If the disturbed south-east region of the cluster is excluded from
the analysis, our results on shape, normalization, scaling properties of
density, temperature, entropy, and cooling time profiles are fully consistent
with those of relaxed, cool core clusters. We compare our total and gas mass
estimates with previous X-ray, lensing, dynamical, and SZ studies. We find good
agreement with other X-ray results, dynamical mass measurements, weak lensing
masses and SZ results. We confirm a discrepancy of a factor ~2 between strong
lensing and X-ray mass determinations and find a gross mismatch between our
total mass estimate and the mass reconstructed through the combination of both
strong and weak lensing. We explore the effervescent heating scenario in the
core of RX J1347.5-1145 and find support to the picture that AGN outflows and
heat conduction are able to quenching radiative cooling.


title:
Potential energy curves and transition moments for the excimer states
  0u+ (3P1) and 1u (3P2) of Ar2

abstract:
  Exactly solvable rererence potentials of several smoothly joined Morse-type
components were constructed for the lowest two excimer states of Ar2 molecule.
The parameters of the potentials have been ascertained by fitting to the
experimental data, and they are reliable in a wide range of nuclear
separations. A large number of quantum mechanical Franck-Condon factors for
bound-free and bound-bound transitions have been calculated and compared with
the observed spectroscopic features. The fitting procedure also involved dipole
transition moments, which have been adjusted to the known radiative lifetimes
of the vibrational levels. The resulting potential energy curves accurately
reproduce the first and the second emission continua of Ar2* as well as the
oscillatory spectrum related to their inner turning point region. The numbering
and the positions of the vibrational levels reported by Herman et al. [P. R.
Herman, P. E. LaRocque, and B. P. Stoicheff, J. Chem. Phys. 89, 4535 (1988)]
have been confirmed.


title:
Connections between real polynomial solutions of hypergeometric-type
  differential equations with Rodrigues formula

abstract:
  Starting from the Rodrigues representation of polynomial solutions of the
general hypergeometric-type differential equation complementary polynomials are
constructed using a natural method. Among the key results is a generating
function in closed form leading to short and transparent derivations of
recursion relations and an addition theorem. The complementary polynomials
satisfy a hypergeometric-type differential equation themselves, have a
three-term recursion among others and obey Rodrigues formulas. Applications to
the classical polynomials are given.


title: Strong extinction of a far-field laser beam by a single quantum dot

abstract:
  Through the utilization of index-matched GaAs immersion lens techniques we
demonstrate a record extinction (12%) of a far-field focused laser by a single
InAs/GaAs quantum dot. This contrast level enables us to report for the first
time resonant laser transmission spectroscopy on a single InAs/GaAs quantum dot
without the need for phase-sensitive lock-in detection.


title: Two Stellar Components in the Halo of the Milky Way

abstract:
  The halo of the Milky Way provides unique elemental abundance and kinematic
information on the first objects to form in the Universe, which can be used to
tightly constrain models of galaxy formation and evolution. Although the halo
was once considered a single component, evidence for its dichotomy has slowly
emerged in recent years from inspection of small samples of halo objects. Here
we show that the halo is indeed clearly divisible into two broadly overlapping
structural components -- an inner and an outer halo -- that exhibit different
spatial density profiles, stellar orbits and stellar metallicities (abundances
of elements heavier than helium). The inner halo has a modest net prograde
rotation, whereas the outer halo exhibits a net retrograde rotation and a peak
metallicity one-third that of the inner halo. These properties indicate that
the individual halo components probably formed in fundamentally different ways,
through successive dissipational (inner) and dissipationless (outer) mergers
and tidal disruption of proto-Galactic clumps.


title:
Recollement of Deformed Preprojective Algebras and the Calogero-Moser
  Correspondence

abstract:
  The aim of this paper is to clarify the relation between the following
objects: $ (a) $ rank 1 projective modules (ideals) over the first Weyl algebra
$ A_1(\C)$; $ (b) $ simple modules over deformed preprojective algebras $
\Pi_{\lambda}(Q) $ introduced by Crawley-Boevey and Holland; and $ (c) $ simple
modules over the rational Cherednik algebras $ H_{0,c}(S_n) $ associated to
symmetric groups. The isomorphism classes of each type of these objects can be
parametrized geometrically by the same space (namely, the Calogero-Moser
algebraic varieties); however, no natural functors between the corresponding
module categories seem to be known. We construct such functors by translating
our earlier results on $\A$-modules over $ A_1 $ to a more familiar setting of
representation theory. In the last section we extend our construction to the
case of Kleinian singularities $ \C^2/\Gamma $, where $ \Gamma $ is a finite
cyclic subgroup of $ \SL(2, \C) $.


title: Relations among Supersymmetric Lattice Gauge Theories via Orbifolding

abstract:
  We show how to derive Catterall's supersymmetric lattice gauge theories
directly from the general principle of orbifolding followed by a variant of the
usual deconstruction. These theories are forced to be complexified due to a
clash between charge assignments under U(1)-symmetries and lattice assignments
in terms of scalar, vector and tensor components for the fermions. Other
prescriptions for how to discretize the theory follow automatically by
orbifolding and deconstruction. We find that Catterall's complexified model for
the two-dimensional N=(2,2) theory has two independent preserved
supersymmetries. We comment on consistent truncations to lattice theories
without this complexification and with the correct continuum limit. The
construction of lattice theories this way is general, and can be used to derive
new supersymmetric lattice theories through the orbifolding procedure. As an
example, we apply the prescription to topologically twisted four-dimensional
N=2 supersymmetric Yang-Mills theory. We show that a consistent truncation is
closely related to the lattice formulation previously given by Sugino.


title:
A Generic Deployment Framework for Grid Computing and Distributed
  Applications

abstract:
  Deployment of distributed applications on large systems, and especially on
grid infrastructures, becomes a more and more complex task. Grid users spend a
lot of time to prepare, install and configure middleware and application
binaries on nodes, and eventually start their applications. The problem is that
the deployment process is composed of many heterogeneous tasks that have to be
orchestrated in a specific correct order. As a consequence, the automatization
of the deployment process is currently very difficult to reach. To address this
problem, we propose in this paper a generic deployment framework allowing to
automatize the execution of heterogeneous tasks composing the whole deployment
process. Our approach is based on a reification as software components of all
required deployment mechanisms or existing tools. Grid users only have to
describe the configuration to deploy in a simple natural language instead of
programming or scripting how the deployment process is executed. As a toy
example, this framework is used to deploy CORBA component-based applications
and OpenCCM middleware on one thousand nodes of the French Grid5000
infrastructure.


title:
Application of a design space exploration tool to enhance interleaver
  generation

abstract:
  This paper presents a methodology to efficiently explore the design space of
communication adapters. In most digital signal processing (DSP) applications,
the overall performance of the system is significantly affected by
communication architectures, as a consequence the designers need specifically
optimized adapters. By explicitly modeling these communications within an
effective graph-theoretic model and analysis framework, we automatically
generate an optimized architecture, named Space-Time AdapteR (STAR). Our design
flow inputs a C description of Input/Output data scheduling, and user
requirements (throughput, latency, parallelism...), and formalizes
communication constraints through a Resource Constraints Graph (RCG). Design
space exploration is then performed through associated tools, to synthesize a
STAR component under time-to-market constraints. The proposed approach has been
tested to design an industrial data mixing block example: an Ultra-Wideband
interleaver.


title: Quasi-invariance properties of a class of subordinators

abstract:
  We study absolute-continuity properties of a class of stochastic processes,
including the gamma and the Dirichlet processes. We prove that the laws of a
general class of non-linear transformations of such processes are locally
equivalent to the law of the original process and we compute explicitly the
associated Radon-Nikodym densities. This work unifies and generalizes to random
non-linear transformations several previous results on quasi-invariance of
gamma and Dirichlet processes.


title:
Axial Nucleon and Nucleon to Delta form fractors and the
  Goldberger-Treiman Relations from Lattice QCD

abstract:
  We evaluate the nucleon axial form factor, $G_A(q^2)$, and induced
pseudoscalar form factor, $G_p(q^2)$, as well as the pion-nucleon form factor,
$G_{\pi N N}(q^2)$, in lattice QCD. We also evaluate the corresponding nucleon
to $\Delta$ transition form factors, $C_5^A(q^2)$ and $C_6^A(q^2)$, and the
pion-nucleon-$\Delta$ form factor $G_{\pi N\Delta}(q^2)$. The nucleon form
factors are evaluated in the quenched theory and with two degenerate flavors of
dynamical Wilson fermions. The nucleon to $\Delta$ form factors, besides Wilson
fermions, are evaluated using domain wall valence fermions with staggered sea
quark configurations for pion masses as low as about 350 MeV. Using these form
factors, together with an evaluation of the renormalized quark mass, we
investigate the validity of the diagonal and non-diagonal Goldberger-Treiman
relations. The ratios $G_{\pi N\Delta}(q^2)/G_{\pi NN}(q^2)$ and
$2C_5^A(q^2)/G_A(q^2)$ are constant as a function of the momentum transfer
squared and show almost no dependence on the quark mass. We confirm equality of
these two ratios consistent with the Goldberger-Treiman relations extracting a
mean value of $1.61(2)$.


title: Unbound exotic nuclei studied by projectile fragmentation

abstract:
  We call "projectile fragmentation" of neutron halo nuclei the elastic breakup
(diffraction) reaction, when the observable studied is the neutron-core
relative energy spectrum. This observable has been measured in relation to the
Coulomb breakup on heavy target and recently also on light targets. Such data
enlighten the effect of the neutron final state interaction with the core of
origin. Projectile fragmentation is studied here by a time dependent model for
the excitation of a nucleon from a bound state to a continuum resonant state in
a neutron-core complex potential which acts as a final state interaction.
  The final state is described by an optical model S-matrix so that both
resonant and non resonant states of any continuum energy can be studied as well
as deeply bound initial states. It turns out that due to the coupling between
the initial and final states, the neutron-core free particle phase shifts are
modified, in the exit channel, by an additional phase.
  Some typical numerical calculations for the relevant observables are
presented and compared to experimental data. It is suggest that the excitation
energy spectra of an unbound nucleus might reflect the structure of the parent
nucleus from whose fragmentation they are obtained.


title:
Oscillation regimes of a solid-state ring laser with active beat note
  stabilization : from a chaotic device to a ring laser gyroscope

abstract:
  We report experimental and theoretical study of a rotating diode-pumped
Nd-YAG ring laser with active beat note stabilization. Our experimental setup
is described in the usual Maxwell-Bloch formalism. We analytically derive a
stability condition and some frequency response characteristics for the
solid-state ring laser gyroscope, illustrating the important role of mode
coupling effects on the dynamics of such a device. Experimental data are
presented and compared with the theory on the basis of realistic laser
parameters, showing a very good agreement. Our results illustrate the duality
between the very rich non linear dynamics of the diode-pumped solid-state ring
laser (including chaotic behavior) and the possibility to obtain a very stable
beat note, resulting in a potentially new kind of rotation sensor.


title:
Bayesian Calibrated Significance Levels Applied to the Spectral Tilt and
  Hemispherical Asymmetry

abstract:
  Bayesian model selection provides a formal method of determining the level of
support for new parameters in a model. However, if there is not a specific
enough underlying physical motivation for the new parameters it can be hard to
assign them meaningful priors, an essential ingredient of Bayesian model
selection. Here we look at methods maximizing the prior so as to work out what
is the maximum support the data could give for the new parameters. If the
maximum support is not high enough then one can confidently conclude that the
new parameters are unnecessary without needing to worry that some other prior
may make them significant. We discuss a computationally efficient means of
doing this which involves mapping p-values onto upper bounds of the Bayes
factor (or odds) for the new parameters. A p-value of 0.05 ($1.96\sigma$)
corresponds to odds less than or equal to 5:2 which is below the `weak' support
at best threshold. A p-value of 0.0003 ($3.6\sigma$) corresponds to odds of
less than or equal to 150:1 which is the `strong' support at best threshold.
Applying this method we find that the odds on the scalar spectral index being
different from one are 49:1 at best. We also find that the odds that there is
primordial hemispherical asymmetry in the cosmic microwave background are 9:1
at best.


title: Oxide spintronics

abstract:
  Concomitant with the development of metal-based spintronics in the late
1980's and 1990's, important advances were made on the growth of high-quality
oxide thin films and heterostructures. While this was at first motivated by the
discovery of high-temperature superconductivity in perovskite Cu oxides, this
technological breakthrough was soon applied to other transition metal oxides,
and notably mixed-valence manganites. The discovery of colossal
magnetoresistance in manganite films triggered an intense research activity on
these materials, but the first notable impact of magnetic oxides in the field
of spintronics was the use of such manganites as electrodes in magnetic tunnel
junctions, yielding tunnel magnetoresistance ratios one order of magnitude
larger than what had been obtained with transition metal electrodes. Since
then, the research on oxide spintronics has been intense with the latest
developments focused on diluted magnetic oxides and more recently on
multiferroics. In this paper, we will review the most important results on
oxide spintronics, emphasizing materials physics as well as spin-dependent
transport phenomena, and finally give some perspectives on how the flurry of
new magnetic oxides could be useful for next-generation spintronics devices.


title:
AC conductivity of graphene: from tight-binding model to 2+1-dimensional
  quantum electrodynamics

abstract:
  We consider the relationship between the tight-binding Hamiltonian of the
two-dimensional honeycomb lattice of carbon atoms with nearest neighbor hopping
only and the 2+1 dimensional Hamiltonian of quantum electrodynamics which
follows in the continuum limit. We pay particular attention to the symmetries
of the free Dirac fermions including spatial inversion, time reversal, charge
conjugation and chirality. We illustrate the power of such a mapping by
considering the effect of the possible symmetry breaking which corresponds to
the creation of a finite Dirac mass, on various optical properties. In
particular, we consider the diagonal AC conductivity with emphasis on how the
finite Dirac mass might manifest itself in experiment. The optical sum rules
for the diagonal and Hall conductivities are discussed.


title:
Relativistic Three-Fermion Wave Equations in Reformulated QED and
  Relativistic Effects in Muonium Minus

abstract:
  The variational method, within the Hamiltonian formalism of reformulated QED
is used to determine relativistic wave equations for a system of three fermions
of arbitrary mass interacting electromagnetically. The interaction kernels of
the equations are, in essence, the invariant $\mathcal{M}$ matrices in lowest
order. The equations are used to obtain relativistic $O(\alpha^2)$ corrections
to the non-relativistic ground state energy levels of the Muonium negative ion
($\mu^+ e^- e^-$) as well as of $\mathrm{Ps}^-$ and $\mathrm{H}^-$, using
approximate variational three-body wave functions. The results are compared
with other calculations, where available. The relativistic correction for
Mu$^-$ is found to be $-1.0773 \times 10^{-4}$ eV.


title:
Tomographic Representation of Minisuperspace Quantum Cosmology and
  Noether Symmetries

abstract:
  The probability representation, in which cosmological quantum states are
described by a standard positive probability distribution, is constructed for
minisuperspace models selected by Noether symmetries. In such a case, the
tomographic probability distribution provides the classical evolution for the
models and can be considered an approach to select "observable" universes. Some
specific examples, derived from Extended Theories of Gravity, are worked out.
We discuss also how to connect tomograms, symmetries and cosmological
parameters.


title: Neutrino Backgrounds to Dark Matter Searches

abstract:
  Neutrino coherent scattering cross sections can be as large as 10^{-39} cm^2,
while current dark matter experiments have sensitivities to WIMP coherent
scattering cross sections five orders of magnitude smaller; future experiments
plan to have sensitivities to cross sections as small as 10^{-48} cm^2. With
large target masses and few keV recoil energy detection thresholds, neutral
current coherent scattering of solar neutrinos becomes an irreducible
background in dark matter searches. In the current zero-background analysis
paradigm, neutrino coherent scattering will limit the achievable sensitivity to
dark matter scattering cross sections, at the level of 10^{-46} cm^2.


title: Unconventional elasticity in smectic-A elastomers

abstract:
  We study two aspects of the elasticity of smectic-$A$ elastomers that make
these materials genuinely and qualitatively different from conventional
uniaxial rubbers. Under strain applied parallel to the layer normal, monodomain
smectic-$A$ elastomers exhibit a drastic change in Young's modulus above a
threshold strain value of about 3%, as has been measured in experiments by
Nishikawa and Finkelmann [Macromol. Chem. Phys. {\bf 200}, 312 (1999)]. Our
theory predicts that such strains induce a transition to a smectic-$C$-like
state and that it is this transition that causes the change in elastic modulus.
We calculate the stress-strain behavior as well as the tilt of the smectic
layers and the molecular orientation for strain along the layer normal, and we
compare our findings with the experimental data. We also study the
electroclinic effect in chiral smectic-$A^\ast$ elastomers. According to
experiments by Lehmann {\em et al}. [Nature {\bf 410}, 447 (2001)] and
K\"{o}hler {\em et al}. [Applied Physics A {\bf 80}, 381 (2003)], this effect
leads in smectic-$A^\ast$ elastomers to a giant or, respectively, at least very
large lateral electrostriction. Incorporating polarization into our theory, we
calculate the height change of smectic-$A^\ast$ elastomer films in response to
a lateral external electric field, and we compare this result to the
experimental findings.


title: Independence property and hyperbolic groups

abstract:
  We prove that existentially closed $CSA$-groups have the independence
property. This is done by showing that there exist words having the
independence property relatively to the class of torsion-free hyperbolic
groups.


title: Dynamical tunneling in macroscopic systems

abstract:
  We investigate macroscopic dynamical quantum tunneling (MDQT) in the driven
Duffing oscillator, charateristic for Josephson junction physics and
nanomechanics. Under resonant conditions between stable coexisting states of
such systems we calculate the tunneling rate. In macroscopic systems coupled to
a heat bath, MDQT can be masked by driving-induced activation. We compare both
processes, identify conditions under which tunneling can be detected with
present day experimental means and suggest a protocol for its observation.


title:
Impact of the Neutrino Magnetic Moment on the Neutrino Fluxes and the
  Electron Fraction in core-collapse Supernovae

abstract:
  We explore the effect of the neutrino magnetic moment on neutrino scattering
with matter in a core-collapse Supernova. We study the impact both on the
neutrino fluxes and on the electron fraction. We find that sizeable
modifications require very large magnetic moments both for Dirac and Majorana
neutrinos.


title: On a generalization of Dehn's algorithm

abstract:
  Viewing Dehn's algorithm as a rewriting system, we generalise to allow an
alphabet containing letters which do not necessarily represent group elements.
This extends the class of groups for which the algorithm solves the word
problem to include nilpotent groups, many relatively hyperbolic groups
including geometrically finite groups and fundamental groups of certain
geometrically decomposable manifolds. The class has several nice closure
properties. We also show that if a group has an infinite subgroup and one of
exponential growth, and they commute, then it does not admit such an algorithm.
We dub these Cannon's algorithms.


title:
Contact Interactions and Resonance-Like Physics at Present and Future
  Colliders from Unparticles

abstract:
  High scale conformal physics can lead to unusual unparticle stuff at our low
energies. In this paper we discuss how the exchange of unparticles between
Standard Model fields can lead to new contact interaction physics as well as a
pseudoresonance-like structure, an unresonance, that might be observable at the
Tevatron or LHC in, e.g., the Drell-Yan channel. The specific signatures of
this scenario are quite unique and can be used to easily identify this new
physics given sufficient integrated luminosity.


title:
Precise Determination of the I=2 pipi Scattering Length from
  Mixed-Action Lattice QCD

abstract:
  The I=2 pipi scattering length is calculated in fully-dynamical lattice QCD
with domain-wall valence quarks on the asqtad-improved coarse MILC
configurations (with fourth-rooted staggered sea quarks) at four light-quark
masses. Two- and three-flavor mixed-action chiral perturbation theory at
next-to-leading order is used to perform the chiral and continuum
extrapolations. At the physical charged pion mass, we find m_pi a_pipi(I=2) =
-0.04330 +- 0.00042, where the error bar combines the statistical and
systematic uncertainties in quadrature.


title:
Final state radiation and a possibility to test a pion-photon
  interaction model near two-pion threshold

abstract:
  Final state radiation in the process $e^+e^-\to\pi^+\pi^-$ is considered for
the cuts used in the analysis of KLOE data at large angles. By means of a Monte
Carlo event generator FEVA, effects of non-pointlike behaviour of pions are
estimated in the framework of Resonance Perturbation Theory. An additional
complication related with the $\phi$ meson intermediate state is taken into
account and the corresponding contributions (the direct decay
$\phi\to\pi^+\pi^-\gamma$ and the double resonance decay
$\phi\to\rho^\pm\pi^\mp\to\pi^+\pi^-\gamma$) are added to FEVA. A method to
test effects of non-pointlike behaviour of pions in a model-independent way is
proposed.


title: On the discreteness and rationality of F-jumping coefficients

abstract:
  This paper studies the jumping coefficients of principal ideals of regular
local rings.
  Recently M. Blickle, M. Mustata and K. Smith showed that, when $R$ is of
essentially finite type over a field and $F$-finite, bounded intervals contain
finitely many jumping coefficients and that those are rational. In a later
paper they extended these results to principal ideals of $F$-finite complete
regular local rings. The aim of this paper is to extend these results on the
discreteness and rationality of jumping coefficients to principal ideals of
arbitrary (i.e. not necessarily $F$-finite) excellent regular local rings
containing fields of positive characteristic.
  Our proof uses a very different method: we do not use $D$-modules and instead
we analyze the modules of nilpotents elements in the injective hull or $R$
under some non-standard Frobenius actions. This new method undoubtedly holds a
potential for more applications.


title: Using integral transforms to estimate higher order derivatives

abstract:
  Integral transformations are used to estimate high order derivatives of
various special functions. Applications are given to numerical integration,
where estimates of high order derivatives of the integrand are needed to
achieve bounds on the error. The main idea is to find a suitable integral
representation of the function whose derivatives are to be estimated,
differentiate repeatedly under the integral sign, and estimate the resulting
integral.


title:
A Comparative Study of Optical and Ultraviolet Effective Temperatures
  for DA White Dwarfs from the IUE Archive

abstract:
  We present a comparative study of effective temperatures determined from the
hydrogen Balmer lines and from the UV energy distribution for 140 DA white
dwarfs drawn from the IUE archive. Our results indicate that the optical and UV
temperatures of the majority of stars below T~40,000 K and within ~75 pc are in
fairly good agreement given the uncertainties. At higher temperatures and/or
larger distances, however, significant discrepancies are observed. Several
mechanisms are investigated to account for these discrepancies including the
effect of interstellar reddening, the presence of metals in the photosphere,
and the existence of unresolved binary white dwarfs. The results of our
analysis reveal that wavelength-dependent extinction is the most natural
explanation for the observed temperature differences. We also attempt to
predict the differences in optical and UV temperatures expected from unresolved
degenerate binaries by performing an exhaustive simulation of composite model
spectra. In light of these simulations, we then discuss some known double
degenerates and identify new binary candidates by restricting our analysis to
stars located within 75 pc where the effect of interstellar reddening is
significantly reduced.


title: Duality of antidiagonals and pipe dreams

abstract:
  Weighted enumeration of reduced pipe dreams (or rc-graphs) results in a
combinatorial expression for Schubert polynomials. The duality between the set
of reduced pipe dreams and certain antidiagonals has important geometric
implications [A. Knutson and E. Miller, Gr\"obner geometry of Schubert
polynomials, Ann. Math. 161, 1245-1318]. The original proof of the duality was
roundabout, relying on the algebra of certain monomial ideals and a recursive
characterization of reduced pipe dreams. This paper provides a direct
combinatorial proof.


title: The Solar Radius in the EUV during the Cycle XXIII

abstract:
  Aims. To determine the solar transition region and coronal radius at EUV
wavelengths and its time evolution during Solar Cycle XXIII.
  Methods. We use daily 30.4 and 17.1 nm images obtained by the Extreme
Ultraviolet Imager (EIT) aboard the SoHO satellite and derive the solar radius
by fitting a circle to the limb brightness ring.
  Results. The weighted mean of the temporal series gives (967''.56 +/- 0''.04)
and (969''.54 +/- 0''.02) at 30.4 and 17.1 nm respectively. No significant
correlation was found with the solar cycle at any of the two wavelengths.
  Conclusions. Since the temperature formation of the 30.4 nm line is between
(60 - 80) 10^3 K (Transition Region), the obtained result is bigger than that
derived from present atmospheric models. On the contrary this height is
compatible with radio models.


title:
Effect of antiferromagnetic spin correlations on lattice distortion and
  charge ordering in Pr$_{0.5}$Ca$_{1.5}$MnO$_{4}$

abstract:
  We use neutron scattering to study the lattice and magnetic structure of the
layered half-doped manganite Pr$_{0.5}$Ca$_{1.5}$MnO$_4$. On cooling from high
temperature, the system first becomes charge- and orbital- ordered (CO/OO) near
$T_{CO}=300$ K and then develops checkerboard-like antiferromagnetic (AF) order
below $T_{N}=130$ K. At temperatures above $T_{N}$ but below $T_{CO}$
($T_N<T<T_{CO}$), the appearance of short-range AF spin correlations suppresses
the CO/OO induced orthorhombic strain, contrasting with other half-doped
manganites, where AF order has no observable effect on the lattice distortion.
These results suggest that a strong spin-lattice coupling and the competition
between AF exchange and CO/OO ordering ultimately determines the
low-temperature properties of the system.


title:
Enhancement of the dielectron continuum in sqrt{s_NN} = 200 GeV Au+Au
  collisions

abstract:
  The PHENIX experiment has measured the dielectron continuum in sqrt{s_NN} =
200 GeV Au+Au collisions. In minimum bias collisions the dielectron yield in
the mass range between 150 and 750 MeV/c^2 is enhanced by a factor of 3.4 +/-
0.2(stat.) +/- 1.3(syst.) +/- 0.7(model) compared to the expectation from our
model of hadron decays. The integrated yield increases faster with the
centrality of the collisions than the number of participating nucleons,
suggesting emission from scattering processes in the hot and dense medium. The
continuum yield between the masses of the phi and the J/psi mesons is
consistent with expectations from correlated c-cbar production, though other
mechanisms are not ruled out.


title: Massive Clumps in the NGC 6334 Star Forming Region

abstract:
  We report observations of dust continuum emission at 1.2 mm toward the star
forming region NGC 6334 made with the SEST SIMBA bolometer array. The
observations cover an area of $\sim 2$ square degrees with approximately
uniform noise. We detected 181 clumps spanning almost three orders of magnitude
in mass (3\Msun$-6\times10^3$ \Msun) and with sizes in the range 0.1--1.0 pc.
We find that the clump mass function $dN/d\log M$ is well fit with a power law
of the mass with exponent -0.6 (or equivalently $dN/dM \propto M^{-1.6}$). The
derived exponent is similar to those obtained from molecular line emission
surveys and is significantly different from that of the stellar initial mass
function. We investigated changes in the mass spectrum by changing the
assumptions on the temperature distribution of the clumps and on the
contribution of free-free emission to the 1.2 mm emission, and found little
changes on the exponent. The Cumulative Mass Distribution Function is also
analyzed giving consistent results in a mass range excluding the high-mass end
where a power-law fit is no longer valid. The masses and sizes of the clumps
observed in NGC 6334 indicate that they are not direct progenitors of stars and
that the process of fragmentation determines the distribution of masses later
on or occurs at smaller spatial scales. The spatial distribution of the clumps
in NGC 6334 reveals clustering which is strikingly similar to that exhibited by
young stars in other star forming regions. A power law fit to the surface
density of companions gives $\Sigma\propto \theta^{-0.62}$.


title: The Hubbard model: bosonic excitations and zero-frequency constants

abstract:
  A fully self-consistent calculation of the bosonic dynamics of the Hubbard
model is developed within the Composite Operator Method. From one side we
consider a basic set of fermionic composite operators (Hubbard fields) and
calculate the retarded propagators. On the other side we consider a basic set
of bosonic composite operators (charge, spin and pair) and calculate the causal
propagators. The equations for the Green's functions (GF) (retarded and
causal), studied in the polar approximation, are coupled and depend on a set of
parameters not determined by the dynamics. First, the pair sector is
self-consistently solved together with the fermionic one and the zero-frequency
constants (ZFC) are calculated not assuming the ergodic value, but fixing the
representation of the GF in such a way to maintain the constrains required by
the algebra of the composite fields. Then, the scheme to compute the charge and
spin sectors, ZFCs included, is given in terms of the fermionic and pair
correlators.


title: Implicit function density computation

abstract:
  If two random variables X and A are functionally related via f(X)=A for some
strictly monotone continuously differentiable function f:R->R, the distribution
of X may easily be computed from the distribution of A.


title:
Separability of a family of one parameter W and GHZ multiqubit states
  using Abe-Rajagopal q-conditional entropy approach

abstract:
  We employ conditional Tsallis q entropies to study the separability of
symmetric one parameter W and GHZ multiqubit mixed states. The strongest
limitation on separability is realized in the limit q-->infinity, and is found
to be much superior to the condition obtained using the von Neumann conditional
entropy (q=1 case). Except for the example of two qubit and three qubit
symmetric states of GHZ family, the $q$-conditional entropy method leads to
sufficient - but not necessary - conditions on separability.


title: The spectral density function of a toric variety

abstract:
  For a Kahler manifold (X, \omega) with a holomorphic line bundle L and metric
h such that the Chern form of L is \omega, the spectral measures are the
measures \mu_N = \sum |s_{N,i}|^2 \nu, where \{s_{N,i}\}_i is an
L^2-orthonormal basis for H^0(X, L^{\otimes N}), and \nu is Liouville measure.
We study the asymptotics in N of \mu_N for (X, L) a Hamiltonian toric manifold,
and give a precise expansion in terms of powers 1/N^j and data on the moment
polytope \Delta of the Hamiltonian torus K acting on X. In addition, for an
infinitesimal character k of K and the unique unit eigensection s_{Nk} for the
character Nk of the torus action on H^0(X, L^N), we give a similar expansion
for the measures \mu_{Nk} = |s_{Nk}|^2 \nu. A final remark shows that the
eigenbasis \{s_{k}, k \in \Delta \cap \mathbb{Z}^{\dim K} \} is a
Bohr-Sommerfeld basis in the sense of Tyurin. Some of the present results are
related to work of Shiffman, Tate and Zelditch. The present paper uses no
microlocal analysis, but rather an Euler-Maclaurin formula for Delzant
polytopes.


title:
Experimental observation of strong photon localization in disordered
  photonic crystal waveguides

abstract:
  We demonstrate experimentally that structural perturbations imposed on
highly-dispersive photonic crystal-based waveguides give rise to spectral
features that bear signatures of Anderson localization. Sharp resonances with
the effective Qs of over 30,000 are found in scattering spectra of disordered
waveguides. The resonances are observed in a ~20-nm bandwidth centered at the
cutoff of slowly-guided Bloch-modes. Their origin can be explained with
interference of coherently scattered electromagnetic waves which results in the
formation of a narrow impurity (or localization) band populated with spectrally
distinct quasistates. Standard photon localization criteria are fulfilled in
the localization band.


title:
Population synthesis of radio and gamma-ray millisecond pulsars from the
  Galactic disk

abstract:
  We present results of a population synthesis of millisecond pulsars from the
Galactic disk. Excluding globular clusters, we model the spatial distribution
of millisecond pulsars by assuming their birth in the Galactic disk with a
random kick velocity and evolve them to the present within the Galactic
potential. We assume that normal and millisecond pulsars are standard candles
described with a common radio luminosity model that invokes a new relationship
between radio core and cone emission suggested by recent studies. In modeling
the radio emission beams, we explore the relativistic effects of time delay,
aberration and sweepback of the open field lines. While these effects are
essential in understanding pulse profiles, the phase-averaged flux is
adequately described without a relativistic model. We use a polar cap
acceleration model for the gamma-ray emission. We present the preliminary
results of our recent study and the implications for observing millisecond
pulsars with GLAST and AGILE.


title:
Turbulent transport of material particles: An experimental study of
  finite size effects

abstract:
  We use an acoustic Lagrangian tracking technique, particularly adapted to
measurements in open flows, and a versatile material particles generator (in
the form of soap bubbles with adjustable size and density) to characterize
Lagrangian statistics of finite sized, neutrally bouyant, particles transported
in an isotropic turbulent flow of air. We vary the size of the particles in a
range corresponding to turbulent inertial scales and explore how the turbulent
forcing experienced by the particles depends on their size. We show that, while
the global shape of the intermittent acceleration probability density function
does not depend significantly on particle size, the acceleration variance of
the particles decreases as they become larger in agreement with the classical
scaling for the spectrum of Eulerian pressure fluctuations in the carrier flow.


title: Carbon and Strontium Abundances of Metal-Poor Stars

abstract:
  We present carbon and strontium abundances for 100 metal-poor stars measured
from R$\sim $7000 spectra obtained with the Echellette Spectrograph and Imager
at the Keck Observatory. Using spectral synthesis of the G-band region, we have
derived carbon abundances for stars ranging from [Fe/H]$=-1.3$ to
[Fe/H]$=-3.8$. The formal errors are $\sim 0.2$ dex in [C/Fe]. The strontium
abundance in these stars was measured using spectral synthesis of the resonance
line at 4215 {\AA}. Using these two abundance measurments along with the barium
abundances from our previous study of these stars, we show it is possible to
identify neutron-capture-rich stars with our spectra. We find, as in other
studies, a large scatter in [C/Fe] below [Fe/H]$ = -2$. Of the stars with
[Fe/H]$<-2$, 9$\pm$4% can be classified as carbon-rich metal-poor stars. The Sr
and Ba abundances show that three of the carbon-rich stars are
neutron-capture-rich, while two have normal Ba and Sr. This fraction of carbon
enhanced stars is consistent with other studies that include this metallicity
range.


title:
On McQuillan's "tautological inequality" and the Weyl-Ahlfors theory of
  associated curves

abstract:
  In 1941, L. Ahlfors gave another proof of a 1933 theorem of H. Cartan on
approximation to hyperplanes of holomorphic curves in P^n. Ahlfors' proof built
on earlier work of H. and J. Weyl (1938), and proved Cartan's theorem by
studying the associated curves of the holomorphic curve. This work has
subsequently been reworked by H.-H. Wu in 1970, using differential geometry, M.
Cowen and P. A. Griffiths in 1976, further emphasizing curvature, and by Y.-T.
Siu in 1987 and 1990, emphasizing meromorphic connections. This paper gives
another variation of the proof, motivated by successive minima as in the proof
of Schmidt's Subspace Theorem, and using McQuillan's "tautological inequality."
In this proof, essentially all of the analysis is encapsulated within a
modified McQuillan-like inequality, so that most of the proof primarily uses
methods of algebraic geometry, in particular flag varieties. A diophantine
conjecture based on McQuillan's inequality is also posed.


title:
The Future is Now: the Formation of Single Low Mass White Dwarfs in the
  Solar Neighborhood

abstract:
  Low mass helium-core white dwarfs (M < 0.45 Msun) can be produced from
interacting binary systems, and traditionally all of them have been attributed
to this channel. However, a low mass white dwarf could also result from a
single star that experiences severe mass loss on the first ascent giant branch.
A large population of low mass He-core white dwarfs has been discovered in the
old metal-rich cluster NGC 6791. There is therefore a mechanism in clusters to
produce low mass white dwarfs without requiring binary star interactions, and
we search for evidence of a similar population in field white dwarfs. We argue
that there is a significant field population (of order half of the detected
systems) that arises from old metal rich stars which truncate their evolution
prior to the helium flash from severe mass loss. There is a consistent absence
of evidence for nearby companions in a large fraction of low mass white dwarfs.
The number of old metal-rich field dwarfs is also comparable with the
apparently single low mass white dwarf population, and our revised estimate for
the space density of low mass white dwarfs produced from binary interactions is
also compatible with theoretical expectations. This indicates that this channel
of stellar evolution, hitherto thought hypothetical only, has been in operation
in our own Galaxy for many billions of years. One strong implication of our
model is that single low mass white dwarfs should be good targets for planet
searches because they are likely to arise from metal-rich progenitors. We also
discuss other observational tests and implications, including the potential
impact on SN Ia rates and the frequency of planetary nebulae.


title: Seismic study of the chemical composition of the solar convection zone

abstract:
  Recent downward revision of solar heavy-element abundances using
three-dimensional atmospheric model has introduced serious discrepancies
between standard solar models and helioseismic inferences about solar
structure. In this paper, we investigate the possibility of determining the
heavy-element abundances using helioseismic inversion techniques with the hope
of providing an independent estimate. We use the adiabatic index, Gamma_1
(logarithmic partial derivative of pressure with respect to density at constant
entropy) as a probe to examine the effects of the total heavy-element
abundance, as well as the effects due to the abundance of individual elements.
Our inversion results show that the new, lower, abundance increases the
discrepancy between the Sun and the solar models.


title: The Radio Properties of Type Ibc Supernovae

abstract:
  Over the past few years, long-duration gamma-ray bursts (GRBs), including the
subclass of X-ray flashes (XRFs), have been revealed to be a rare variety of
Type Ibc supernova (SN Ibc). While all these events result from the death of
massive stars, the electromagnetic luminosities of GRBs and XRFs exceed those
of ordinary Type Ibc SNe by many orders of magnitude. The observed diversity of
stellar death corresponds to large variations in the energy, velocity, and
geometry of the explosion ejecta. Using multi-wavelength (radio, optical,
X-ray) observations of the nearest GRBs, XRFs, and SNe Ibc, I show that while
GRBs and XRFs couple at least 10^48 erg to relativistic material, SNe Ibc
typically couple less than 10^48 erg to their fastest (albeit non-relativistic)
outflows. Specifically, I find that less than 3% of local SNe Ibc show any
evidence for association with a GRB or XRF. Recently, a new class of GRBs and
XRFs has been revealed which are under-luminous in comparison with the
statistical sample of GRBs. Owing to their faint high-energy emission, these
sub-energetic bursts are only detectable nearby (z < 0.1) and are likely 10
times more common than cosmological GRBs. In comparison with local SNe Ibc and
typical GRBs/XRFs, these explosions are intermediate in terms of both
volumetric rate and energetics. Yet the essential physical process that causes
a dying star to produce a GRB, XRF, or sub-energetic burst, and not just a SN,
remains a crucial open question. Progress requires a detailed understanding of
ordinary SNe Ibc which will be facilitated with the launch of wide-field
optical surveys in the near future.


title: A Dark Core in Abell 520

abstract:
  The rich cluster Abell 520 (z=0.201) exhibits truly extreme and puzzling
multi-wavelength characteristics. It may best be described as a "cosmic train
wreck." It is a major merger showing abundant evidence for ram pressure
stripping, with a clear offset in the gas distribution compared to the galaxies
(as in the bullet cluster 1E 0657-558). However, the most striking feature is a
massive dark core (721 h_70 M_sun/L_sun) in our weak lensing mass
reconstruction. The core coincides with the central X-ray emission peak, but is
largely devoid of galaxies. An unusually low mass to light ratio region lies
500 kpc to the east, and coincides with a shock feature visible in radio
observations of the cluster. Although a displacement between the X-ray gas and
the galaxy/dark matter distributions may be expected in a merger, a mass peak
without galaxies cannot be easily explained within the current collisionless
dark matter paradigm. Interestingly, the integrated gas mass fraction (~0.15),
mass-to-light ratio (220 h_70 M_sun/L_sun), and position on the X-ray
luminosity-temperature and mass-temperature relations are unremarkable. Thus
gross properties and scaling relations are not always useful indicators of the
dynamical state of clusters.


title: Beyond Twisted Tori

abstract:
  Exploiting the fact that Kaluza-Klein monopoles and the associated
generalized orbifold planes are sources for geometrical fluxes, omega, we show
that the standard constraint omega.omega=0, valid for superstring
compactifications on twisted tori, can be consistently relaxed. This leads to
novel possibilities for constructing superstring models with fluxes and
localized sources, as well as for stabilizing moduli. This also explains the
ten-dimensional origin of a family of N=4 gauged supergravities, whose
interpretation in type-IIA orientifold compactifications was lacking.


title:
Dark matter from "strong gravity" - consistent with CRESST, CoGeNT and
  DAMA/LIBRA

abstract:
  Kelso, Hooper and Buckley [arXiv:1110.5338] found CRESST, CoGeNT and
DAMA/LIBRA results are consistent with 10 - 15 GeV dark matter particles.
Hennawi and Ostriker [arXiv:astro-ph/0108203] analyzed supermassive black hole
formation in the centers of galaxies, finding a best fit for dark matter
(self-interaction cross-section)/mass ratio = 0.02 cm^{2}/g, with round-off
error of 25%. Combining the Hennawi/Ostriker result with the "strong gravity"
model for dark matter [arXiv:0706.3050] requires dark matter particles with
mass between 10.5 GeV and 17.5 GeV, overlapping the Kelso/Hooper/Buckley dark
matter particle mass range.


title:
Molecular Dipolar Crystals as High Fidelity Quantum Memory for Hybrid
  Quantum Computing

abstract:
  We study collective excitations of rotational and spin states of an ensemble
of polar molecules, which are prepared in a dipolar crystalline phase, as a
candidate for a high fidelity quantum memory. While dipolar crystals are formed
in the high density limit of cold clouds of polar molecules under 1D and 2D
trapping conditions, the crystalline structure protects the molecular qubits
from detrimental effects of short range collisions. We calculate the lifetime
of the quantum memory by identifying the dominant decoherence mechanisms, and
estimate their effects on gate operations, when a molecular ensemble qubit is
transferred to a superconducting strip line cavity (circuit QED). In the case
rotational excitations coupled by dipole-dipole interactions we identify
phonons as the main limitation of the life time of qubits. We study specific
setups and conditions, where the coupling to the phonon modes is minimized.
Detailed results are presented for a 1D dipolar chain.


title: Two Classes of Hot Jupiters

abstract:
  We identify two classes of transiting planet, based on their equilibrium
temperatures and Safronov numbers. We examine various possible explanations for
the dichotomy. It may reflect the influence of planet or planetesimal
scattering in determining when planetary migration stops. Another possibility
is that some planets lose more mass to evaporation than others. If this
evaporation process preferentially removes Helium from the planet, the
consequent reduction in the mean molecular weight may explain why some planets
have anomalously large radii.


title:
A Survey of Intrinsic Absorption in Active Galaxies using the Far
  Ultraviolet Spectroscopic Explorer

abstract:
  We present a survey of 72 Seyfert galaxies and quasars observed by the it Far
Ultraviolet Spectroscopic Explorer (FUSE). We have determined that 72 of 253
available active galactic nuclei (AGN) targets are viable targets for detection
of intrinsic absorption lines. We examined these spectra for signs of intrinsic
absorption in the O VI doublet (lambda 1031.9, 1037.6) and Lyman beta (lambda
1025.7). The fraction of Seyfert 1 galaxies and low-redshift quasars at z <
0.15 that show evidence of intrinsic UV absorption is ~50%, which is slightly
lower than Crenshaw et al. (1999) found (60%) based on a smaller sample of
Seyfert 1 galaxies observed with the Hubble Space Telescope (HST). With this
new fraction we find a global covering factor of the absorbing gas with respect
to the central nucleus of ~0.4. Our survey is to date the largest searching for
intrinsic UV absorption with high spectral resolution, and is the first step
toward a more comprehensive study of intrinsic absorption in low-redshift AGN.


title: The perfect lens on a finite bandwidth

abstract:
  The resolution associated with the so-called perfect lens of thickness $d$ is
$-2\pi d/\ln(|\chi+2|/2)$. Here the susceptibility $\chi$ is a Hermitian
function in $H^2$ of the upper half-plane, i.e., a $H^2$ function satisfying
$\chi(-\omega)=\bar{\chi(\omega)}$. An additional requirement is that the
imaginary part of $\chi$ be nonnegative for nonnegative arguments. Given an
interval $I$ on the positive half-axis, we compute the distance in
$L^\infty(I)$ from a negative constant to this class of functions. This result
gives a surprisingly simple and explicit formula for the optimal resolution of
the perfect lens on a finite bandwidth.


title: A primer on the (2+1) Einstein universe

abstract:
  The Einstein universe is the conformal compactification of Minkowski space.
It also arises as the ideal boundary of anti-de Sitter space. The purpose of
this article is to develop the synthetic geometry of the Einstein universe in
terms of its homogeneous submanifolds and causal structure, with particular
emphasis on dimension $2 + 1$, in which there is a rich interplay with
symplectic geometry.


title: Neutrino-driven explosions twenty years after SN1987A

abstract:
  The neutrino-heating mechanism remains a viable possibility for the cause of
the explosion in a wide mass range of supernova progenitors. This is
demonstrated by recent two-dimensional hydrodynamic simulations with detailed,
energy-dependent neutrino transport. Neutrino-driven explosions were not only
found for stars in the range of 8-10 solar masses with ONeMg cores and in case
of the iron core collapse of a progenitor with 11 solar masses, but also for a
``typical'' progenitor model of 15 solar masses. For such more massive stars,
however, the explosion occurs significantly later than so far thought, and is
crucially supported by large-amplitude bipolar oscillations due to the
nonradial standing accretion shock instability (SASI), whose low (dipole and
quadrupole) modes can develop large growth rates in conditions where convective
instability is damped or even suppressed. The dominance of low-mode deformation
at the time of shock revival has been recognized as a possible explanation of
large pulsar kicks and of large-scale mixing phenomena observed in supernovae
like SN 1987A.