title:
Proper Motions and Brightness Variations of Nonthermal X-ray Filaments
  in the Cassiopeia A Supernova Remnant

abstract:
  We present Chandra ACIS X-ray observations of the Galactic supernova remnant
Cassiopeia A taken in December 2007. Combining these data with previous
archival Chandra observations taken in 2000, 2002, and 2004, we estimate the
remnant's forward shock velocity at various points around the outermost shell
to range between 4200 and 5200 +/- 500 km/s. Using these results together with
previous analyses of Cas A's X-ray emission, we present a model for the
evolution of Cas A and find that it's expansion is well fit by a rho_ej ~
r^{-(7-9)} ejecta profile running into a circumstellar wind. We further find
that while the position of the reverse shock in this model is consistent with
that measured in the X-rays, in order to match the forward shock velocity and
radius we had to assume that ~ 30% of the explosion energy has gone into
accelerating cosmic rays at the forward shock. The new X-ray images also show
that brightness variations can occur for some forward shock filaments like that
seen for several nonthermal filaments seen projected in the interior of the
remnant. Spectral fits to exterior forward shock filaments and interior
nonthermal filaments show that they exhibit similar spectra. This together with
similar flux variations suggests that interior nonthermal filaments might be
simply forward shock filaments seen in projection and not located at the
reverse shock as has been recently proposed.


title: Sensitivity to parameters of STIRAP in a Cooper-Pair Box

abstract:
  The rapid experimental progress in the field of superconducting nanocircuits
gives rise to an increasing quest for advanced quantum-control techniques for
these macroscopically coherent systems. Here we demonstrate theoretically that
stimulated Raman adiabatic passage (STIRAP), a well-established method in
quantum optics, should be possible with the quantronium setup of a Cooper-pair
box. We find the parameters which optimize the procedure and show how the
scheme appears to be robust against decoherence and should be realizable even
with the existing technology.


title: Radiation damping, noncommutativity and duality

abstract:
  In this work, our main objective is to construct a N=2 supersymmetric
extension of the nonrelativistic $(2+1)$-dimensional model describing the
radiation damping on the noncommutative plane with scalar (electric) and vector
(magnetic) interactions by the N=2 superfield technique. We also introduce a
dual equivalent action to the radiation damping one using the Noether
procedure.


title:
Hilbert's fourteenth problem over finite fields, and a conjecture on the
  cone of curves

abstract:
  We give examples over arbitrary fields of rings of invariants that are not
finitely generated. The group involved can be as small as three copies of the
additive group, as in Mukai's examples over the complex numbers. The failure of
finite generation comes from certain elliptic fibrations or abelian surface
fibrations having positive Mordell-Weil rank.
  Our work suggests a generalization of the Morrison-Kawamata cone conjecture
from Calabi-Yau varieties to klt Calabi-Yau pairs. We prove the conjecture in
dimension 2 in the case of minimal rational elliptic surfaces.


title:
Quantization of Sine-Gordon solitons on the circle: semiclassical vs.
  exact results

abstract:
  We consider the semiclassical quantization of sine-Gordon solitons on the
circle with periodic and anti-periodic boundary conditions. The 1-loop quantum
corrections to the mass of the solitons are determined using zeta function
regularization in the integral representation. We compare the semiclassical
results with exact numerical calculations in the literature and find excellent
agreement even outside the plain semiclassical regime.


title:
Measurement of the color-suppressed decays anti-B0->D(*)0 pi0
  /omega/eta/eta prime branching fractions

abstract:
  We report results on the branching fraction ($\mathcal{BF}$) measurement of
the color-suppressed decays $\bar{B}^0\to D^0 \pi^0$, $D^{*0}\pi^0$, $D^0\eta$,
$D^{*0}\eta$, $D^0\omega$, $D^{*0}\omega$, $D^0\eta^{\prime}$, and
$D^{*0}\eta^{\prime}$. The result is based on a sample of $(454\pm 5)\times
10^{6} B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance from 1999 to
2007, with the $\babar$ detector at the PEP-II storage rings at the Stanford
Linear Accelerator Center. The measurements are compared to theoretical
predictions by factorization, SCET and pQCD.


title:
Observation of the Isotopic Evolution of Pressurized Water Reactor Fuel
  Using an Antineutrino Detector

abstract:
  By operating an antineutrino detector of simple design during several fuel
cycles, we have observed long term changes in antineutrino flux that result
from the isotopic evolution of a commercial Pressurized Water Reactor (PWR).
Measurements made with simple antineutrino detectors of this kind offer an
alternative means for verifying fissile inventories at reactors, as part of
International Atomic Energy Agency (IAEA) and other reactor safeguards regimes.


title: Fourier transform and middle convolution for irregular D-modules

abstract:
  S.Block and H.Esnault constructed the local Fourier transform for D-modules.
We present a different approach to the local Fourier transform, which makes its
properties almost tautological. We apply the local Fourier transform to compute
the local version of Katz's middle convolution.


title: Measurement of CP-Violating Asymmetries in the B0->K+K-Ks Dalitz Plot

abstract:
  We present a preliminary measurement of CP-violation parameters in the decay
B0->K+K-Ks, using approximately 465 million BBbar events collected by the BABAR
detector at SLAC. Reconstructing the neutral kaon as Ks->pi+pi- or Ks->pi0pi0,
we analyze the Dalitz plot distribution and measure fractions to intermediate
states. We extract CP parameters from the asymmetries in amplitudes and phases
between B0 and B0bar decays across the Dalitz plot. From a fit to the whole
Dalitz plot, we measure beta_eff = 0.44 +/- 0.07 +/- 0.02, A_CP = 0.03 +/- 0.07
+/- 0.02, where the first uncertainties are statistical and the second ones are
systematic. For decays to phiKs, we measure beta_eff = 0.13 +/- 0.13 +/- 0.02,
A_CP = 0.14 +/- 0.19 +/- 0.02. For decays to f0Ks, we measure beta_eff = 0.15
+/- 0.13 +/- 0.03, A_CP = 0.01 +/- 0.26 +/- 0.07. From a fit to the region of
the Dalitz plot with m_{K+K-}>1.1 GeV/c^2, we measure beta_eff = 0.52 +/- 0.08
+/- 0.03, A_CP = 0.05 +/- 0.09 +/- 0.04.


title: Effective theory for the cosmological generation of structure

abstract:
  The current understanding of structure formation in the early universe is
mainly built on a magnification of quantum fluctuations in an initial vacuum
state during an early phase of accelerated universe expansion. One usually
describes this process by solving equations for a quantum state of matter on a
given expanding background space-time, followed by decoherence arguments for
the emergence of classical inhomogeneities from the quantum fluctuations. Here,
we formulate the coupling of quantum matter fields to a dynamical gravitational
background in an effective framework which allows the inclusion of
back-reaction effects. It is shown how quantum fluctuations couple to classical
inhomogeneities and can thus manage to generate cosmic structure in an evolving
background. Several specific effects follow from a qualitative analysis of the
back-reaction, including a likely reduction of the overall amplitude of power
in the cosmic microwave background, the occurrence of small non-Gaussianities,
and a possible suppression of power for odd modes on large scales without
parity violation.


title:
Unifying cosmological and recent time variations of fundamental
  couplings

abstract:
  A number of positive and null results on the time variation of fundamental
constants have been reported. It is difficult to judge whether or not these
claims are mutually consistent, since the observable quantities depend on
several parameters, namely the coupling strengths and masses of particles. The
evolution of these coupling-parameters over cosmological history is also a
priori unknown. A direct comparison requires a relation between the couplings.
We explore several distinct scenarios based on unification of gauge couplings,
providing a representative (though not exhaustive) sample of such relations.
For each scenario we obtain a characteristic time dependence and discuss
whether a monotonic time evolution is allowed. For all scenarios, some
contradictions between different observations appear. We show how a clear
observational determination of non-zero variations would test the dominant
mechanism of varying couplings within unified theories.


title: Observation of ZZ production in ppbar collisions at sqrt(s) = 1.96 TeV

abstract:
  We present an observation for ZZ -> l+l-l'+l'- (l, l' = e or mu) production
in ppbar collisions at a center-of-mass energy of sqrt(s) = 1.96 TeV. Using 1.7
fb-1 of data collected by the D0 experiment at the Fermilab Tevatron Collider,
we observe three candidate events with an expected background of 0.14 +0.03
-0.02 events. The significance of this observation is 5.3 standard deviations.
The combination of D0 results in this channel, as well as in ZZ -> l+l-nunubar,
yields a significance of 5.7 standard deviations and a combined cross section
of sigma(ZZ) = 1.60 +/- 0.63 (stat.) +0.16 -0.17 (syst.) pb.


title:
Spin-independent elastic WIMP scattering and the DAMA annual modulation
  signal

abstract:
  We discuss the interpretation of the annual modulation signal seen in the
DAMA experiment in terms of spin-independent elastic WIMP scattering. Taking
into account channeling in the crystal as well as the spectral signature of the
modulation signal we find that the low-mass WIMP region consistent with DAMA
data is confined to WIMP masses close to $m_\chi \simeq 12$ GeV, in
disagreement with the constraints from CDMS and XENON. We conclude that even if
channeling is taken into account this interpretation of the DAMA modulation
signal is disfavoured. There are no overlap regions in the parameter space at
90% CL and a consistency test gives the probability of $1.2\times 10^{-5}$. We
study the robustness of this result with respect to variations of the WIMP
velocity distribution in our galaxy, by changing various parameters of the
distribution function, and by using the results of a realistic N-body dark
matter simulation. We find that only by making rather extreme assumptions
regarding halo properties can we obtain agreement between DAMA and CDMS/XENON.


title:
Strong and radiative decays of the scalars f0(980) and a0(980) in a
  hadronic molecule approach

abstract:
  We analyze the electromagnetic and strong decay properties of the light
scalars a0(980) and f0(980) within a hadronic molecule interpretation. Both
scalars are discussed within a covariant and gauge invariant model which also
allows for finite size effects due to their spatially extended structure in the
K Kbar-bound state picture. Allowing for f0-a0 mixing we also study its
influence on the radiative decays f0/a0 to gamma gamma, f0/a0 to gamma omega,
and f0/a0 to gamma rho as well as the phi production of the f0 and a0.
Furthermore, we apply our formalism to describe the strong f0 to pi pi and a0
to pi eta decay properties.


title: Gravity Waves and Linear Inflation from Axion Monodromy

abstract:
  Wrapped branes in string compactifications introduce a monodromy that extends
the field range of individual closed-string axions to beyond the Planck scale.
Furthermore, approximate shift symmetries of the system naturally control
corrections to the axion potential. This suggests a general mechanism for
chaotic inflation driven by monodromy-extended closed-string axions. We
systematically analyze this possibility and show that the mechanism is
compatible with moduli stabilization and can be realized in many types of
compactifications, including warped Calabi-Yau manifolds and more general
Ricci-curved spaces. In this broad class of models, the potential is linear in
the canonical inflaton field, predicting a tensor to scalar ratio r=0.07
accessible to upcoming cosmic microwave background (CMB) observations.


title: Low Energy Probes of CP Violation in a Flavor Blind MSSM

abstract:
  We analyze the low energy implications of a flavor blind supersymmetric
scenario (where the CKM matrix is the only source of flavor violation) in the
presence of new CP violating but flavor conserving phases in the soft sector.
We find that the best probes of this rather restricted scenario are i) the
electric dipole moments (EDMs) of the electron (d_e) and the neutron (d_n) and
ii) flavor changing and CP violating processes in B systems, like the CP
asymmetries in b->s gamma and B->phi(eta^')K_S, i.e. A_CP(b->s gamma) and
S_phi(eta^')K_S, respectively. The non-standard values for S_phi(eta^')K_S,
measured at the B factories, can find a natural explanation within our scenario
and this would unambiguously imply i) positive and often large (non-standard)
values for A_CP(b->s gamma) and ii) a lower bound for the electron and neutron
EDMs at the level of d_e,n > 10^-28 e cm. Moreover, we predict positive New
Physics (NP) contributions to epsilon_K which could be welcomed in view of the
recently lowered Standard Model value for epsilon_K. Interestingly, an
explanation for the non-standard values for S_phi(eta^')K_S can also naturally
lead to an explanation for the anomaly of the muon anomalous magnetic moment.
Finally, we outline the role and the interplay of the direct NP searches at the
LHC with the indirect searches performed by low energy flavor physics
observables.


title:
Local antiferromagnetic correlations in the iron pnictide
  superconductors LaFeAsO{1-x}F{x} and Ca(Fe,Co)2As2 as seen via normal-state
  susceptibility

abstract:
  We have studied the interplay of magnetism and superconductivity in
LaFeAsO$_{1-x}$F$_x$ and Ca(Fe$_{1-x}$Co$_x$)$_2$As$_2$. While
antiferromagnetic spin density wave formation is suppressed and
superconductivity evolves, all samples show a doping independent strong
increase of the normal state susceptibility upon heating which appears a
general feature of iron pnictides. The data provide evidence for robust local
antiferromagnetic correlations persisting even in the superconducting regime of
the phase diagram.


title: Fine Structure of Avalanches in the Abelian Sandpile Model

abstract:
  We study the two-dimensional Abelian Sandpile Model on a square lattice of
linear size L. We introduce the notion of avalanche's fine structure and
compare the behavior of avalanches and waves of toppling. We show that
according to the degree of complexity in the fine structure of avalanches,
which is a direct consequence of the intricate superposition of the boundaries
of successive waves, avalanches fall into two different categories. We propose
scaling ans\"{a}tz for these avalanche types and verify them numerically. We
find that while the first type of avalanches has a simple scaling behavior, the
second (complex) type is characterized by an avalanche-size dependent scaling
exponent. This provides a framework within which one can understand the failure
of a consistent scaling behavior in this model.


title:
Trans-Debye Scale Plasma Modeling & Stochastic GRB Wakefield Plasma
  Processes

abstract:
  Modeling plasma physical processes in astrophysical context demands for both
detailed kinetics and large scale development of the electromagnetic field
densities.
  We present a new framework for modeling plasma physics of hot tenuous plasmas
by a two-split scheme, in which the large scale fields are modeled by means of
a particle-in-cell (PIC) code, and in which binary collision processes and
single-particle processes are modeled through a Monte-Carlo approach. Our novel
simulation tool -- the PhotonPlasma code -- is a unique hybrid model; it
combines a highly parallelized (Vlasov) particle-in-cell approach with
continuous weighting of particles and a sub-Debye Monte-Carlo binary particle
interaction framework.
  As an illustration of the capabilities we present results from a numerical
study of Gamma-Ray Burst - Circumburst Medium interaction and plasma
preconditioning via Compton scattering. We argue that important microphysical
processes can only viably be investigated by means of hybrid codes such as the
PhotonPlasma code.
  Our first results from 3D simulations with this new simulation tool suggest
that magnetic fields and plasma filaments are created in the wakefield of
prompt gamma-ray bursts. Furthermore, the photon flux density gradient impacts
on particle acceleration in the burst head and wakefield. We discuss some
possible implications of the circumburst medium being preconditioned for a
trailing afterglow shock front. We also discuss important improvements for
future studies of GRB wakefields processes, using the PhotonPlasma code.


title: Support union recovery in high-dimensional multivariate regression

abstract:
  In multivariate regression, a $K$-dimensional response vector is regressed
upon a common set of $p$ covariates, with a matrix $B^*\in\mathbb{R}^{p\times
K}$ of regression coefficients. We study the behavior of the multivariate group
Lasso, in which block regularization based on the $\ell_1/\ell_2$ norm is used
for support union recovery, or recovery of the set of $s$ rows for which $B^*$
is nonzero. Under high-dimensional scaling, we show that the multivariate group
Lasso exhibits a threshold for the recovery of the exact row pattern with high
probability over the random design and noise that is specified by the sample
complexity parameter $\theta(n,p,s):=n/[2\psi(B^*)\log(p-s)]$. Here $n$ is the
sample size, and $\psi(B^*)$ is a sparsity-overlap function measuring a
combination of the sparsities and overlaps of the $K$-regression coefficient
vectors that constitute the model. We prove that the multivariate group Lasso
succeeds for problem sequences $(n,p,s)$ such that $\theta(n,p,s)$ exceeds a
critical level $\theta_u$, and fails for sequences such that $\theta(n,p,s)$
lies below a critical level $\theta_{\ell}$. For the special case of the
standard Gaussian ensemble, we show that $\theta_{\ell}=\theta_u$ so that the
characterization is sharp. The sparsity-overlap function $\psi(B^*)$ reveals
that, if the design is uncorrelated on the active rows, $\ell_1/\ell_2$
regularization for multivariate regression never harms performance relative to
an ordinary Lasso approach and can yield substantial improvements in sample
complexity (up to a factor of $K$) when the coefficient vectors are suitably
orthogonal. For more general designs, it is possible for the ordinary Lasso to
outperform the multivariate group Lasso. We complement our analysis with
simulations that demonstrate the sharpness of our theoretical results, even for
relatively small problems.


title:
Origin and consequence of an unpinned helical magnet: application to
  partial order in MnSi under pressure

abstract:
  We study a classical ferromagnetic Heisenberg model in the presence of
Dzyaloshinskii-Moriya interactions on the corner-shared triangle lattice formed
by the Mn sites of MnSi. We show that a sizable spin helicity can be obtained
only when the microscopic Moriya vectors lie parallel to the Mn-Mn bonds.
Further, such vectors are shown to produce an unpinned helical order
characterized by a particular ordering wavevector magnitude but unpinned
direction, dubbed partial order, at physically realizable temperatures. A
consequence of such an unpinned helical ordering is that the neutron scattering
intensity is sharply peaked at this wavevector magnitude. The surface formed by
connecting these wavevectors is a sphere, around which the neutron scattering
weight is spread. We further show that the observed neutron scattering
intensity can be anisotropic along this surface and that this anisotropy is
dependent on the experimentalist's choice of lattice Bragg peak through a
geometric factor. A neutron scattering measurement near the Bragg point
($\frac{2\pi}{a}$,$\frac{2\pi}{a}$,0) naturally leads to a highest intensity
along the (1,1,0) direction consistent with the observed anisotropy in MnSi
[Pfleiderer {\it{et al.}} Nature {\bf{427}} 227 (2004)]. A possible mechanism
for pinning the helical order, and a way to distinguish an ordered and a
partially ordered state in the context of neutron scattering are discussed.


title:
Comparison of Numerical and Post-Newtonian Waveforms for Generic
  Precessing Black-Hole Binaries

abstract:
  We compare waveforms and orbital dynamics from the first long-term, fully
non-linear, numerical simulations of a generic black-hole binary configuration
with post-Newtonian predictions. The binary has mass ratio q~0.8 with
arbitrarily oriented spins of magnitude S_1/m_1^2~0.6 and S_2/m_2^2~0.4 and
orbits 9 times prior to merger. The numerical simulation starts with an initial
separation of r~11M, with orbital parameters determined by initial 2.5PN and
3.5PN post-Newtonian evolutions of a quasi-circular binary with an initial
separation of r=50M. The resulting binaries have very little eccentricity
according to the 2.5PN and 3.5PN systems, but show significant eccentricities
of e~0.01-0.02 and e~0.002-0.005 in the respective numerical simulations, thus
demonstrating that 3.5PN significantly reduces the eccentricity of the binary
compared to 2.5PN. We perform three numerical evolutions from r~11M with
maximum resolutions of h=M/48,M/53.3,M/59.3, to verify numerical convergence.
We observe a reasonably good agreement between the PN and numerical waveforms,
with an overlap of nearly 99% for the first six cycles of the (l=2,m=+-2)
modes, 91% for the (l=2,m=+-1) modes, and nearly 91% for the (l=3,m=+-3) modes.
The phase differences between numerical and post-Newtonian approximations
appear to be independent of the (l,m) modes considered and relatively small for
the first 3-4 orbits. An advantage of the 3.5 PN model over the 2.5 PN one
seems to be observed, which indicates that still higher PN order (perhaps even
4.0PN) may yield significantly better waveforms. In addition, we identify
features in the waveforms likely related to precession and precession-induced
eccentricity.


title: Determining the extragalactic extinction law with SALT

abstract:
  We present CCD imaging observations of early-type galaxies with dark lanes
obtained with the Southern African Large Telescope (SALT) during its
performance-verification phase. We derive the extinction law by the
extragalactic dust in the dark lanes in the spectral range 1.11mu m^{-1} <
lambda^{-1} < 2.94 mu m^{-1} by fitting model galaxies to the unextinguished
parts of the image, and subtracting from these the actual images. We find that
the extinction curves run parallel to the Galactic extinction curve, which
implies that the properties of dust in the extragalactic enviroment are similar
to those of the Milky Way. The ratio of the total V band extinction to the
selective extinction between the V and B bands is derived for each galaxy with
an average of 2.82+-0.38, compared to a canonical value of 3.1 for the Milky
Way. The similar values imply that galaxies with well-defined dark lanes have
characteristic dust grain sizes similar to those of Galactic dust.


title: From Kadanoff-Baym dynamics to off-shell parton transport

abstract:
  This review provides a written version of the lectures presented at the
Schladming Winter School 2008, Austria, on 'Nonequilibrium Aspects of Quantum
Field Theory'. In particular, it shows the way from quantum-field theory - in
two-particle irreducible approximation - to the Kadanoff-Baym (KB) equations
and various approximations schemes of the KB equations in phase space. This
ultimately leads to the formulation of an off-shell transport theory that well
incorporates the underlying quantum physics. Remarkably, these transport
equations may be solved within a testparticle representation that allows to
study non-equilibrium quantum systems in the weak and strong coupling regime.
Actual applications to dilepton production in heavy-ion reactions are presented
in comparison with available data. The approach, furthermore, allows to address
the hadronization process from partonic to hadronic degrees of freedom.


title:
Bulge Formation by the Coalescence of Giant Clumps in Primordial Disk
  Galaxies

abstract:
  Gas-rich disks in the early universe are highly turbulent and have giant
star-forming clumps. Models suggest the clumps form by gravitational
instabilities, and if they resist disruption by star formation, then they
interact, lose angular momentum, and migrate to the center to form a bulge.
Here we study the properties of the bulges formed by this mechanism. They are
all thick, slowly rotating, and have a high Sersic index, like classical
bulges. Their rapid formation should also give them relatively high
alpha-element abundances. We consider fourteen low-resolution models and four
high-resolution models, three of which have supernova feedback. All models have
an active halo, stellar disk, and gaseous disk, three of the models have a
pre-existing bulge and three others have a cuspy dark matter halo. All show the
same basic result except the one with the highest feedback, in which the clumps
are quickly destroyed and the disk thickens too much. The coalescence of
massive disk clumps in the center of a galaxy is like a major merger in terms
of orbital mixing. It differs by leaving a bulge with no specific dark matter
component, unlike the merger of individual galaxies. Normal supernova feedback
has little effect because the high turbulent speed in the gas produces tightly
bound clumps. A variety of indirect observations support the model, including
clumpy disks with young bulges at high redshift and bulges with relatively
little dark matter.


title: New estimates for the length of the Erdos-Herzog-Piranian lemniscate

abstract:
  Let p(z) be a monic polynomial of degree n. Consider the lemniscate
L={z:|p(z)|=1}. It has been conjectured that L has the largest length when
p(z)=z^n-1. We show that the length of L attains a local maximum at this
polynomial and prove the asymptotically sharp bound |L|<2n+o(n).


title: Suppression of Magnetic Order by Pressure in BaFe2As2

abstract:
  We performed the dc resistivity and the ZF 75As-NMR measurement of BaFe2As2
under high pressure. The T-P phase diagram of BaFe2As2 determined from
resistivity anomalies and the ZF 75As-NMR clearly revealed that the SDW anomaly
is quite robust against P.


title:
Pair Production of Two-Higgs-Doublet_Model Light Higgs Bosons in $\gamma
  \gamma$ Collisions

abstract:
  We study the production of a pair of light, neutral, CP-even Higgs bosons in
photon--photon collisions within the general Two Higgs Doublet Model (THDM).
This is a process for which the lowest order contribution in both, the Standard
Model and the THDM, appears at one loop. We find that the cross section for
this process can be much larger in the THDM than in the Standard Model and the
number of events expected at the Photon Collider will allow a determination of
some of the parameters in the scalar potential.


title: Global geometry under isotropic Brownian flows

abstract:
  We consider global geometric properties of a codimension one manifold
embedded in Euclidean space, as it evolves under an isotropic and volume
preserving Brownian flow of diffeomorphisms. In particular, we obtain
expressions describing the expected rate of growth of the Lipschitz-Killing
curvatures, or intrinsic volumes, of the manifold under the flow.
  These results shed new light on some of the intriguing growth properties of
flows from a global perspective, rather than the local perspective, on which
there is a much larger literature.


title:
SDSS J120923.7+264047: A new massive galaxy cluster with a bright giant
  arc

abstract:
  Highly magnified lensed galaxies allow us to probe the morphological and
spectroscopic properties of high-redshift stellar systems in great detail.
However, such objects are rare, and there are only a handful of lensed galaxies
which are bright enough for a high-resolution spectroscopic study with current
instrumentation. We report the discovery of a new massive lensing cluster, SDSS
J120923.7+264047, at z=0.558. Present around the cluster core, at angular
distances of up to ~40'', are many arcs and arc candidates, presumably due to
lensing of background galaxies by the cluster gravitational potential. One of
the arcs, 21'' long, has an r-band magnitude of 20, making it one of the
brightest known lensed galaxies. We obtained a low-resolution spectrum of this
galaxy, using the Keck-I telescope, and found it is at redshift of z=1.018.


title:
Insufficiency of the Quantum State for Deducing Observational
  Probabilities

abstract:
  It is usually assumed that the quantum state is sufficient for deducing all
probabilities for a system. This may be true when there is a single observer,
but it is not true in a universe large enough that there are many copies of an
observer. Then the probability of an observation cannot be deduced simply from
the quantum state (say as the expectation value of the projection operator for
the observation, as in traditional quantum theory). One needs additional rules
to get the probabilities. What these rules are is not logically deducible from
the quantum state, so the quantum state itself is insufficient for deducing
observational probabilities. This is the measure problem of cosmology.


title: ODE, RDE and SDE Models of Cell Cycle Dynamics and Clustering in Yeast

abstract:
  Biologists have long observed periodic-like oxygen consumption oscillations
in yeast populations under certain conditions and several unsatisfactory
explanations for this phenomenon have been proposed. These "autonomous
oscillations" have often appeared with periods that are nearly integer divisors
of the calculated doubling time of the culture.
  We hypothesize that these oscillations could be caused by a weak form of cell
cycle synchronization that we call clustering. We develop some novel ordinary
differential equation models of the cell cycle. For these models, and for
random and stochastic perturbations, we give both rigorous proofs and
simulations showing that both positive and negative growth rate feedback within
the cell cycle are possible agents that can cause clustering of populations
within the cell cycle. It occurs for a variety of models and for a broad
selection of parameter values. These results suggest that the clustering
phenomenon is robust and is likely to be observed in nature. Since there are
necessarily an integer number of clusters, clustering would lead to
periodic-like behavior with periods that are nearly integer divisors of the
period of the cell cycle.


title: On the ring structure of spark characters

abstract:
  We give a new description of the ring structure on the differential
characters of a smooth manifold via the smooth hyperspark complex. We show the
explicit product formula, and as an application, calculate the product for
differential characters of the unit circle. Applying the presentation of spark
classes by smooth hypersparks, we give an explicit construction of the
isomorphism between groups of spark classes and the $(p,p)$ part of smooth
Deligne cohomology groups associated to a smooth manifold. We then give a new
direct proof that this is an isomorphism of ring structures.


title: Petal-shape probability areas: complete quantum state discrimination

abstract:
  We find the allowed complex numbers associated with the inner product of N
equally separated pure quantum states. The allowed areas on the unitary complex
plane have the form of petals. A point inside the petal-shape represents a set
of N linearly independent (LI) pure states, and a point on the edge of that
area represents a set of N linearly dependent (LD) pure states. For each one of
those LI sets we study the complete discrimination of its N equi-separated
states combining sequentially the two known strategies: first the unambiguous
identification protocol for LI states, followed, if necessary, by the
error-minimizing measurement scheme for LD states. We find that the
probabilities of success for both unambiguous and ambiguous discrimination
procedures depend on both the module and the phase of the involved inner
product complex number. We show that, with respect to the phase-parameter, the
maximal probability of discriminating unambiguously the N non-orthogonal pure
states holds just when there no longer be probability of obtaining ambiguously
information about the prepared state by applying the second protocol if the
first one was not successful.


title: Mixing and CP Violation at the Tevatron

abstract:
  Measurements of meson mixing and CP violation parameters obtained by the CDF
and D0 experiments at the Fermilab Tevatron are presented. These include
results on $B_s$ and $D$ meson mixing, and searches for CP violation in the
decay $B^+ \to J/\psi K^+$, in mixing through semileptonic $B_s$ meson decays,
and in the interference between mixing and decay in the process $B_s \to J/\psi
\phi$.


title: Conformal weldings and Dispersionless Toda hierarchy

abstract:
  Given a $C^1$ homeomorphism of the unit circle $\gamma$, let $f$ and $g$ be
respectively the normalized conformal maps from the unit disc and its exterior
so that $\gamma= g^{-1}\circ f$ on the unit circle. In this article, we show
that by suitably defined time variables, the evolutions of the pairs $(g, f)$
and $(g^{-1}, f^{-1})$ can be described by an infinite set of nonlinear partial
differential equations known as dispersionless Toda hierarchy. Relations to the
integrable structure of conformal maps first studied by Wiegmann and Zabrodin
\cite{WZ} are discussed. An extension of the hierarchy which contains both our
solution and the solution of \cite{WZ} is defined.


title: SUSY Searches at the Tevatron

abstract:
  Numerous searches for evidence of supersymmetry at the Tevatron have been
performed by the CDF and D0 collaborations. Recent results are presented here
including squarks and gluinos in jets and missing transverse energy, stop in
several different decay modes, charginos and neutralinos in trileptons,
neutralinos in di-photons, R-parity violating sneutrinos in e+mu events, and
long-lived particles. These explore many variations of SUSY such as MSSM,
mSUGRA, and GMSB. While no evidence of SUSY production is observed, 95% CL
limits on cross sections and SUSY parameter space are set. Most of these limits
are the world's best.


title:
An approximation to density functional theory for an accurate
  calculation of band-gaps of semiconductors

abstract:
  The local-density approximation (LDA), together with the half-occupation
(transition state) is notoriously successful in the calculation of atomic
ionization potentials. When it comes to extended systems, such as a
semiconductor infinite system, it has been very difficult to find a way to
half-ionize because the hole tends to be infinitely extended (a Bloch wave).
The answer to this problem lies in the LDA formalism itself. One proves that
the half-occupation is equivalent to introducing the hole self-energy
(electrostatic and exchange-correlation) into the Schroedinger equation. The
argument then becomes simple: the eigenvalue minus the self-energy has to be
minimized because the atom has a minimal energy. Then one simply proves that
the hole is localized, not infinitely extended, because it must have maximal
self-energy. Then one also arrives at an equation similar to the SIC equation,
but corrected for the removal of just 1/2 electron. Applied to the calculation
of band gaps and effective masses, we use the self-energy calculated in atoms
and attain a precision similar to that of GW, but with the great advantage that
it requires no more computational effort than standard LDA.


title: Trees = Networks ?!?

abstract:
  This work addresses the intrinsic relationship between trees and networks
(i.e. graphs). A complete (invertible) mapping is presented which allows trees
to be mapped into weighted graphs and then backmapped into the original tree
without loss of information. The extension of this methodology to more general
networks, including unweighted structures, is also discussed and illustrated.
It is shown that the identified duality between trees and graphs underlies
several key concepts and issues of current interest in complex networks,
including comprehensive characterization of trees and community detection. For
instance, additional information about tree structures (e.g. phylogenetic
trees) can be immediately obtained by taking into account several off-the-shelf
network measurements -- such as the clustering coefficient, degree correlations
and betweenness centrality. At the same time, the hierarchical structure of
networks, including the respective communities, becomes clear when the network
is represented in terms of the respective tree. Indeed, the network-tree
mapping described in this work provides a simple and yet effective means of
community detection.


title: Coherent control near metallic nanostructures

abstract:
  We study coherent control in the vicinity of metallic nanostructures. Unlike
in the case of control in gas or liquid phase, the collective response of
electrons in a metallic nanostructure can significantly enhance different
frequency components of the control field. This enhancement strongly depends on
the geometry of the nanostructure and can substantially modify the temporal
profile of the local control field. The changes in the amplitude and phase of
the control field near the nanostructure are studied using linear response
theory. The inverse problem of finding the external electromagnetic field to
generate the desired local control field is considered and solved.


title: Dynamics, robustness and fragility of trust

abstract:
  Trust is often conveyed through delegation, or through recommendation. This
makes the trust authorities, who process and publish trust recommendations,
into an attractive target for attacks and spoofing. In some recent empiric
studies, this was shown to lead to a remarkable phenomenon of *adverse
selection*: a greater percentage of unreliable or malicious web merchants were
found among those with certain types of trust certificates, then among those
without. While such findings can be attributed to a lack of diligence in trust
authorities, or even to conflicts of interest, our analysis of trust dynamics
suggests that public trust networks would probably remain vulnerable even if
trust authorities were perfectly diligent. The reason is that the process of
trust building, if trust is not breached too often, naturally leads to
power-law distributions: the rich get richer, the trusted attract more trust.
The evolutionary processes with such distributions, ubiquitous in nature, are
known to be robust with respect to random failures, but vulnerable to adaptive
attacks. We recommend some ways to decrease the vulnerability of trust
building, and suggest some ideas for exploration.


title:
LaMnO$_3$ is a Mott Insulator: an precise definition and an evaluation
  of the local interaction strength

abstract:
  We compare the interaction parameters measured on LaMnO$_3$ to single site
dynamical mean field estimates of the critical correlation strength needed to
drive a Mott transition, finding that the total correlation strength
(electron-electron plus electron-lattice) is very close to but slightly larger
than the critical value, while if the electron lattice interaction is neglected
the model is metallic. Our results emphasize the importance of additional
physics including the buckling of the Mn-O-Mn bonds.


title:
From Equilibrium to Transport Properties of Strongly Correlated Fermi
  Liquids

abstract:
  We summarize recent results regarding the equilibrium and non-equilibrium
behavior of cold dilute atomic gases in the limit in which the two body
scattering length a goes to infinity. In this limit the system is described by
a Galilean invariant (non-relativistic) conformal field theory. We discuss the
low energy effective lagrangian appropriate to the limit a->infinity, and
compute low energy coefficients using an epsilon-expansion. We also show how to
combine the effective lagrangian with kinetic theory in order to compute the
shear viscosity, and compare the kinetic theory predictions to experimental
results extracted from the damping of collective modes in trapped Fermi gases.


title: Neutrino Astrophysics

abstract:
  I review the current status of neutrino astrophysics, including solar
neutrinos; atmospheric neutrinos; neutrino mass and oscillations; supernova
neutrinos; neutrino nucleosynthesis (Big Bang nucleosynthesis, the neutrino
process, the r-process); neutrino cooling and red giants; and high energy
neutrino astronomy.


title: Theoretical Description of Pseudocubic Manganites

abstract:
  A comprehensive theoretical model for the bulk manganite system
La$_{1-x}$(Ca,Sr)$_x$MnO$_3$ is presented. The model includes local and
cooperative Jahn-Teller distortions and the on-site Coulomb and exchange
interaction. The model is is solved in the single-site dynamical mean field
approximation using a solver based on the semiclassical approximation. The
model semi-quantitatively reproduces the observed phase diagram for the doping
$0 \leq x<0.5$ and implies that the manganites are in the strong coupling
region but close to Mott insulator/metal phase boundary. The results establish
a formalism for use in a broader range of calculations, for example on
heterostructures.


title:
Nonradiative Recombination of Excitons in Carbon Nanotubes Mediated by
  Free Charge Carriers

abstract:
  Free electrons or holes can mediate the nonradiative recombination of
excitons in carbon nanotubes. Kinematic constraints arising from the quasi
one-dimensional nature of excitons and charge carriers lead to a thermal
activation barrier for the process. However, a model calculation suggests that
the rate for recombination mediated by a free electron is the same order of
magnitude as that of two-exciton recombination. Small amounts of doping may
contribute to the short exciton lifetimes and low quantum yields observed in
carbon nanotubes.


title:
Breakdown of the Schmid law in bcc molybdenum related to the effect of
  shear stress perpendicular to the slip direction

abstract:
  The breakdown of the Schmid law in bcc metals has been known for a long time.
The asymmetry of shearing in the slip direction <111> in the positive and
negative sense, respectively, commonly identified with the
twinning-antitwinning asymmetry, is undoubtedly one of the reasons. However,
effect of stress components other than the shear stress in the slip direction
may be important. In this paper we investigate by atomistic modeling the effect
of shear stresses perpendicular to the Burgers vector on the glide of a/2<111>
screw dislocations. We show that these shear stresses can significantly elevate
or reduce the critical resolved shear stress (CRSS) in the direction of the
Burgers vector needed for the dislocation motion, i.e. the Peierls stress. This
occurs owing to the changes of the core induced by these stresses. This effect
may be the reason why slip systems with smaller Schmid factors may be preferred
over that with the largest Schmid factor.


title: Boolean formulae, hypergraphs and combinatorial topology

abstract:
  With a view toward studying the homotopy type of spaces of Boolean formulae,
we introduce a simplicial complex, called the theta complex, associated to any
hypergraph, which is the Alexander dual of the more well-known independence
complex. In particular, the set of satisfiable formulae in k-conjunctive normal
form with less than or equal to n variables has the homotopy type of
Theta(Cube(n,n-k)), where Cube(n,n-k) is a hypergraph associated to the
(n-k)-skeleton of an n-cube. We make partial progress in calculating the
homotopy type of theta for these cubical hypergraphs, and we also give
calculations and examples for other hypergraphs as well. Indeed studying the
theta complex of hypergraphs is an interesting problem in its own right.


title: Theory of Manganite Superlattice

abstract:
  A theoretical model is proposed for the (0,0,1) superlattice manganite system
(LaMnO$_3$)$_n$(SrMnO$_3$)$_m$. The model includes the electron-electron,
electron-phonon, and cooperative Jahn-Teller interactions. It is solved using a
version of single-site the dynamical mean field approximation generalized to
incorporate the cooperative Jahn-Teller effect. The phase diagram and
conductivities are calculated. The behavior of the superlattice is found to a
good approximation to be an average over the density-dependent properties of
individual layers, with the density of each layer fixed by electrostatics.


title: Logarithm laws and shrinking target properties

abstract:
  We survey some of the recent developments in the study of logarithm laws and
shrinking target properties for various families of dynamical systems. We
discuss connections to geometry, diophantine approximation, and probability
theory.


title: Rigid irregular connections on P^1

abstract:
  N.Katz's middle convolution algorithm provides a description of rigid
connections on the projective line with regular singularities. We extend the
algorithm by adding the Fourier transform to it. The extended algorithm
provides a description of rigid connections with arbitrary singularities.


title:
Kerr nonlinearities and nonclassical states with superconducting qubits
  and nanomechanical resonators

abstract:
  We propose the use of a superconducting charge qubit capacitively coupled to
two resonant nanomechanical resonators to generate Yurke-Stoler states, i.e.
quantum superpositions of pairs of distinguishable coherent states 180$^\circ$
out of phase with each other. This is achieved by effectively implementing Kerr
nonlinearities induced through application of a strong external driving field
in one of the resonators. A simple study of the effect of dissipation on our
scheme is also presented, and lower bounds of fidelity and purity of the
generated state are calculated. Our procedure to implement a Kerr nonlinearity
in this system may be used for high precision measurements in nanomechanical
resonators.


title:
First order magnetic transition in single crystal CaFe$_2$As$_2$
  detected by $^{75}$As NMR

abstract:
  We report $^{75}$As Nuclear Magnetic Resonance data in a single crystal of
CaFe$_2$As$_2$. The Knight shift, electric field gradient, and spin-lattice
relaxation rate are strongly temperature dependent in the paramagnetic state,
and change discontinuously at the structural transition temperature,
$T_S=T_N=167$ K. Immediately below, the NMR spectra reveal an internal field at
the As site associated with the presence of a commensurate magnetic order.
These results indicate that the structural and magnetic transitions in
CaFe$_2$As$_2$ are first order and strongly coupled, and that the electron
density in the FeAs plane is highly sensitive to the out-of-plane structure.


title: Relay-Assisted User Scheduling in Wireless Networks with Hybrid-ARQ

abstract:
  This paper studies the problem of relay-assisted user scheduling for downlink
wireless transmission. The base station or access point employs hybrid
automatic-repeat-request (HARQ) with the assistance of a set of fixed relays to
serve a set of mobile users. By minimizing a cost function of the queue lengths
at the base station and the number of retransmissions of the head-of-line
packet for each user, the base station can schedule an appropriate user in each
time slot and an appropriate transmitter to serve it. It is shown that a
priority-index policy is optimal for a linear cost function with packets
arriving according to a Poisson process and for an increasing convex cost
function where packets must be drained from the queues at the base station.


title: String Gas Cosmology

abstract:
  String gas cosmology is a string theory-based approach to early universe
cosmology which is based on making use of robust features of string theory such
as the existence of new states and new symmetries. A first goal of string gas
cosmology is to understand how string theory can effect the earliest moments of
cosmology before the effective field theory approach which underlies standard
and inflationary cosmology becomes valid. String gas cosmology may also provide
an alternative to the current standard paradigm of cosmology, the inflationary
universe scenario. Here, the current status of string gas cosmology is
reviewed.


title: Uncertainties in the Anti-neutrino Production at Nuclear Reactors

abstract:
  Anti-neutrino emission rates from nuclear reactors are determined from
thermal power measurements and fission rate calculations. The uncertainties in
these quantities for commercial power plants and their impact on the calculated
interaction rates in electron anti-neutrino detectors is examined. We discuss
reactor-to-reactor correlations between the leading uncertainties and their
relevance to reactor anti-neutrino experiments.


title: Communication in XYZ All-to-All Quantum Networks with a Missing Link

abstract:
  We explicitate the relation between Hamiltonians for networks of interacting
qubits in the XYZ model and graph Laplacians. We then study evolution in
networks in which all sites can communicate with each other. These are modeled
by the complete graph K_{n} and called all-to-all networks. It turns out that
K_{n} does not exhibit perfect state transfer (PST). However, we prove that
deleting an edge in K_{n} allows PST between the two non-adjacent sites, when n
is a multiple of four. An application is routing a qubit over n different
sites, by switching off the link between the sites that we wish to put in
communication. Additionally, we observe that, in certain cases, the unitary
inducing evolution in K_{n} is equivalent to the Grover operator.


title:
Surface tension in an intrinsic curvature model with fixed
  one-dimensional boundaries

abstract:
  A triangulated fixed connectivity surface model is investigated by using the
Monte Carlo simulation technique. In order to have the macroscopic surface
tension \tau, the vertices on the one-dimensional boundaries are fixed as the
edges (=circles) of the tubular surface in the simulations. The size of the
tubular surface is chosen such that the projected area becomes the regular
square of area A. An intrinsic curvature energy with a microscopic bending
rigidity b is included in the Hamiltonian. We found that the model undergoes a
first-order transition of surface fluctuations at finite b, where the surface
tension \tau discontinuously changes. The gap of \tau remains constant at the
transition point in a certain range of values A/N^\prime at sufficiently large
N^\prime, which is the total number of vertices excluding the fixed vertices on
the boundaries. The value of \tau remains almost zero in the wrinkled phase at
the transition point while \tau remains negative finite in the smooth phase in
that range of A/N^\prime.


title: SDE in Random Population Growth

abstract:
  In this paper we extend the recent work of C.A. Braumann \cite{B2007} to the
case of stochastic differential equation with random coefficients. Furthermore,
the relationship of the It\^o-Stratonovich stochastic calculus to studies of
random population growth is also explained.


title: Effects of epidemic threshold definition on disease spread statistics

abstract:
  We study the statistical properties of the SIR epidemics in heterogeneous
networks, when an epidemic is defined as only those SIR propagations that reach
or exceed a minimum size s_c. Using percolation theory to calculate the average
fractional size <M_SIR> of an epidemic, we find that the strength of the
spanning link percolation cluster $P_{\infty}$ is an upper bound to <M_SIR>.
For small values of s_c, $P_{\infty}$ is no longer a good approximation, and
the average fractional size has to be computed directly. The value of s_c for
which $P_{\infty}$ is a good approximation is found to depend on the
transmissibility T of the SIR. We also study Q, the probability that an SIR
propagation reaches the epidemic mass s_c, and find that it is well
characterized by percolation theory. We apply our results to real networks
(DIMES and Tracerouter) to measure the consequences of the choice s_c on
predictions of average outcome sizes of computer failure epidemics.


title: Positive Dehn Twist Expression for a $\mathbb{Z}_3$ action on $\Sigma_g$

abstract:
  A positive Dehn twist product for a $\mathbb{Z}_3$ action with $g+2$ fixed
points on the 2-dimensional closed, compact, oriented surface $\Sigma_g$ is
presented. The homeomorphism invariants of the resulting symplectic 4-manifolds
are computed.


title:
Ranking Catamorphisms and Unranking Anamorphisms on Hereditarily Finite
  Datatypes

abstract:
  Using specializations of unfold and fold on a generic tree data type we
derive unranking and ranking functions providing natural number encodings for
various Hereditarily Finite datatypes.
  In this context, we interpret unranking operations as instances of a generic
anamorphism and ranking operations as instances of the corresponding
catamorphism.
  Starting with Ackerman's Encoding from Hereditarily Finite Sets to Natural
Numbers we define pairings and tuple encodings that provide building blocks for
a theory of Hereditarily Finite Functions.
  The more difficult problem of ranking and unranking Hereditarily Finite
Permutations is then tackled using Lehmer codes and factoradics.
  The self-contained source code of the paper, as generated from a literate
Haskell program, is available at
\url{http://logic.csci.unt.edu/tarau/research/2008/fFUN.zip}.
  Keywords: ranking/unranking, pairing/tupling functions, Ackermann encoding,
hereditarily finite sets, hereditarily finite functions, permutations and
factoradics, computational mathematics, Haskell data representations


title:
A Functional Hitchhiker's Guide to Hereditarily Finite Sets, Ackermann
  Encodings and Pairing Functions

abstract:
  The paper is organized as a self-contained literate Haskell program that
implements elements of an executable finite set theory with focus on
combinatorial generation and arithmetic encodings. The code, tested under GHC
6.6.1, is available at http://logic.csci.unt.edu/tarau/research/2008/fSET.zip .
  We introduce ranking and unranking functions generalizing Ackermann's
encoding to the universe of Hereditarily Finite Sets with Urelements. Then we
build a lazy enumerator for Hereditarily Finite Sets with Urelements that
matches the unranking function provided by the inverse of Ackermann's encoding
and we describe functors between them resulting in arithmetic encodings for
powersets, hypergraphs, ordinals and choice functions. After implementing a
digraph representation of Hereditarily Finite Sets we define {\em decoration
functions} that can recover well-founded sets from encodings of their
associated acyclic digraphs. We conclude with an encoding of arbitrary digraphs
and discuss a concept of duality induced by the set membership relation.
  Keywords: hereditarily finite sets, ranking and unranking functions,
executable set theory, arithmetic encodings, Haskell data representations,
functional programming and computational mathematics


title: The kinematic footprints of five stellar streams in Andromeda's halo

abstract:
  (abridged) We present a spectroscopic analysis of five stellar streams (`A',
`B', `Cr', `Cp' and `D') as well as the extended star cluster, EC4, which lies
within streamC, all discovered in the halo of M31 from our CFHT/MegaCam survey.
These spectroscopic results were initially serendipitous, making use of our
existing observations from the DEep Imaging Multi-Object Spectrograph mounted
on the Keck II telescope, and thereby emphasizing the ubiquity of tidal streams
that account for ~70% of the M31 halo stars in the targeted fields. Subsequent
spectroscopy was then procured in streamCr/p and streamD to trace the velocity
gradient along the streams. For the cluster EC4, candidate member stars with
average [Fe/H]~-1.4 (Fe/H_spec=-1.6), are found at v_{hel}=-285 km/s suggesting
it could be related to streamCp. No similarly obvious cold kinematic candidate
is found for streamD, although candidates are proposed in both of two
spectroscopic pointings along the stream (both at -400 km/s). Spectroscopy near
the edge of streamB suggests a likely kinematic detection, while a candidate
kinematic detection of streamA is found (plausibly associated to M33 rather
than M31). The low dispersion of the streams in kinematics, physical thickness,
and metallicity makes it hard to reconcile with a scenario whereby these stream
structures as an ensemble are related to the giant southern stream. We conclude
that the M31 stellar halo is largely made up of multiple kinematically cold
streams.


title: Novel definition of Grassmann numbers and spinor fields

abstract:
  The goal of this paper is to define fermionic field in terms of
non-orthonormal vierbeins, where fluctuations away from orthonormality are
viewed as fermionic field. Furthermore, Grassmann numbers are defined in a way
that makes literal sense.


title: The properties of penumbral microjets inclination

abstract:
  We investigate the dependence of penumbral microjets inclination on the
position within penumbra. The high cadence observations taken on 10 November
2006 with the Hinode satellite through the \ion{Ca}{ii} H and G--band filters
were analysed to determine the inclination of penumbral microjets. The results
were then compared with the inclination of the magnetic field determined
through the inversion of the spectropolarimetric observations of the same
region. The penumbral microjet inclination is increasing towards the outer edge
of the penumbra. The results suggest that the penumbral microjet follows the
opening magnetic field lines of a vertical flux tube that creates the sunspot.


title:
Evaluation of the Theoretical Uncertainties in the W to Lepton and
  Neutrino Cross Sections at the LHC

abstract:
  We study the sources of systematic errors in the measurement of the W to
lepton and neutrino cross-sections at the LHC. We consider the systematic
errors in both the total cross-section and acceptance for anticipated
experimental cuts. We include the best available analysis of QCD effects at
NNLO in assessing the effect of higher order corrections and PDF and scale
uncertainties on the theoretical acceptance. In addition, we evaluate the error
due to missing NLO electroweak corrections and propose which MC generators and
computational schemes should be implemented to best simulate the events.


title:
Rapidly spinning massive black holes in active galactic nuclei: evidence
  from the black hole mass function

abstract:
  The comparison of the black hole mass function (BHMF) of active galactic
nuclei (AGN) relics with the measured mass function of the massive black holes
in galaxies provides strong evidence for the growth of massive black holes
being dominated by mass accretion. We derive the Eddington ratio distributions
as functions of black hole mass and redshift from a large AGN sample with
measured Eddington ratios given by Kollmeier et al. We find that, even at the
low mass end, most black holes are accreting at Eddington ratio ~0.2, which
implies that the objects accreting at extremely high rates should be rare or
such phases are very short. Using the derived Eddington ratios, we explore the
cosmological evolution of massive black holes with an AGN bolometric luminosity
function (LF). It is found that the resulted BHMF of AGN relics is unable to
match the measured local BHMF of galaxies for any value of (constant) radiative
efficiency. Motivated by Volonteri, Sikora & Lasota's study on the spin
evolution of massive black holes, we assume the radiative efficiency to be
dependent of black hole mass, i.e., it is low for M<10^8 solar masses and it
increases with black hole mass for black holes with >10^8 solar masses. We find
that the BHMF of AGN relics can roughly reproduce the local BHMF of galaxies if
the radiative efficiency ~0.08 for the black holes with <10^8 solar masses and
it increases to ~0.18 for black holes with >10^9 solar masses, which implies
that most massive black holes (>10^9 solar masses) are spinning very rapidly.


title:
Declarative Combinatorics: Boolean Functions, Circuit Synthesis and BDDs
  in Haskell

abstract:
  We describe Haskell implementations of interesting combinatorial generation
algorithms with focus on boolean functions and logic circuit representations.
  First, a complete exact combinational logic circuit synthesizer is described
as a combination of catamorphisms and anamorphisms.
  Using pairing and unpairing functions on natural number representations of
truth tables, we derive an encoding for Binary Decision Diagrams (BDDs) with
the unique property that its boolean evaluation faithfully mimics its
structural conversion to a a natural number through recursive application of a
matching pairing function.
  We then use this result to derive ranking and unranking functions for BDDs
and reduced BDDs.
  Finally, a generalization of the encoding techniques to Multi-Terminal BDDs
is provided.
  The paper is organized as a self-contained literate Haskell program,
available at http://logic.csci.unt.edu/tarau/research/2008/fBDD.zip .
  Keywords: exact combinational logic synthesis, binary decision diagrams,
encodings of boolean functions, pairing/unpairing functions, ranking/unranking
functions for BDDs and MTBDDs, declarative combinatorics in Haskell


title: Effective superpotentials for compact D5-brane Calabi-Yau geometries

abstract:
  For compact Calabi-Yau geometries with D5-branes we study N=1 effective
superpotentials depending on both open- and closed-string fields. We develop
methods to derive the open/closed Picard-Fuchs differential equations, which
control D5-brane deformations as well as complex structure deformations of the
compact Calabi-Yau space. Their solutions encode the flat open/closed
coordinates and the effective superpotential. For two explicit examples of
compact D5-brane Calabi-Yau hypersurface geometries we apply our techniques and
express the calculated superpotentials in terms of flat open/closed
coordinates. By evaluating these superpotentials at their critical points we
reproduce the domain wall tensions that have recently appeared in the
literature. Finally we extract orbifold disk invariants from the
superpotentials, which, up to overall numerical normalizations, correspond to
orbifold disk Gromov-Witten invariants in the mirror geometry.


title: On the Convergence of Optimal Measures

abstract:
  Using recent results of Berman and Boucksom we show that for a non-pluripolar
compact set K in C^d and an admissible weight function w=e^{-\phi} any sequence
of so-called optimal measures converges weak-* to the equilibrium measure
\mu_{K,\phi} of (weighted) Pluripotential Theory for K,\phi.


title:
Experimental mathematics on the magnetic susceptibility of the square
  lattice Ising model

abstract:
  We calculate very long low- and high-temperature series for the
susceptibility $\chi$ of the square lattice Ising model as well as very long
series for the five-particle contribution $\chi^{(5)}$ and six-particle
contribution $\chi^{(6)}$. These calculations have been made possible by the
use of highly optimized polynomial time modular algorithms and a total of more
than 150000 CPU hours on computer clusters. For $\chi^{(5)}$ 10000 terms of the
series are calculated {\it modulo} a single prime, and have been used to find
the linear ODE satisfied by $\chi^{(5)}$ {\it modulo} a prime.
  A diff-Pad\'e analysis of 2000 terms series for $\chi^{(5)}$ and $\chi^{(6)}$
confirms to a very high degree of confidence previous conjectures about the
location and strength of the singularities of the $n$-particle components of
the susceptibility, up to a small set of ``additional'' singularities. We find
the presence of singularities at $w=1/2$ for the linear ODE of $\chi^{(5)}$,
and $w^2= 1/8$ for the ODE of $\chi^{(6)}$, which are {\it not} singularities
of the ``physical'' $\chi^{(5)}$ and $\chi^{(6)},$ that is to say the
series-solutions of the ODE's which are analytic at $w =0$.
  Furthermore, analysis of the long series for $\chi^{(5)}$ (and $\chi^{(6)}$)
combined with the corresponding long series for the full susceptibility $\chi$
yields previously conjectured singularities in some $\chi^{(n)}$, $n \ge 7$.
  We also present a mechanism of resummation of the logarithmic singularities
of the $\chi^{(n)}$ leading to the known power-law critical behaviour occurring
in the full $\chi$, and perform a power spectrum analysis giving strong
arguments in favor of the existence of a natural boundary for the full
susceptibility $\chi$.

categories: math-ph cond-mat.stat-mech hep-th math.MP


title: Skein theory for the D_{2n} planar algebras

abstract:
  We give a combinatorial description of the ``$D_{2n}$ planar algebra,'' by
generators and relations. We explain how the generator interacts with the
Temperley-Lieb braiding. This shows the previously known braiding on the even
part extends to a `braiding up to sign' on the entire planar algebra.
  We give a direct proof that our relations are consistent (using this
`braiding up to sign'), give a complete description of the associated tensor
category and principal graph, and show that the planar algebra is positive
definite. These facts allow us to identify our combinatorial construction with
the standard invariant of the subfactor $D_{2n}$.


title: Tensorial hydrodynamic slip

abstract:
  We describe a tensorial generalization of the Navier slip boundary condition
and illustrate its use in solving for flows around anisotropic textured
surfaces. Tensorial slip can be derived from molecular or microstructural
theories or simply postulated as an constitutive relation, subject to certain
general constraints on the interfacial mobility. The power of the tensor
formalism is to capture complicated effects of surface anisotropy, while
preserving a simple fluid domain. This is demonstrated by exact solutions for
laminar shear flow and pressure-driven flow between parallel plates of
arbitrary and different textures. From such solutions, the effects of rotating
a texture follow from simple matrix algebra. Our results may be useful to
extracting local slip tensors from global measurements, such as the
permeability of a textured channel or the force required to move a patterned
surface, in experiments or simulations.


title: Dynamics of k-core percolation in a random graph

abstract:
  We study the edge deletion process of random graphs near a k-core percolation
point. We find that the time-dependent number of edges in the process exhibits
critically divergent fluctuations. We first show theoretically that the k-core
percolation point is exactly given as the saddle-node bifurcation point in a
dynamical system. We then determine all the exponents for the divergence based
on a universal description of fluctuations near the saddle-node bifurcation.


title: On Time. 5b: Electromagnetic Time

abstract:
  We formulate the 2-body problem of electrodynamics using functional
differential equations, and explain the peculiar features of these equations
which indicate a paradigm shift in physics. We examine the possible empirical
existence of advanced interactions using various absorber theories of
radiation. Functional differential equations were connected to quantum
mechanics in a subsequent paper in this series and in later publications.


title: Foundations of Information Theory

abstract:
  Information is the basic concept of information theory. However, there is no
definition of this concept that can encompass all uses of the term information
in information theories and beyond. Many question a possibility of such a
definition. However, foundations of information theory developed in the context
of the general theory of information made it possible to build such a relevant
and at the same time, encompassing definition. Foundations of information
theory are built in a form of ontological principles, which reflect basic
features of information and information processes.


title:
The correlation of black hole mass with metallicity index of host
  spheroid

abstract:
  We investigate the correlation between the mass of the supermassive black
holes (SMBHs) and metal abundance, using existing data sets. The SMBH mass
$M_{bh}$ is well correlated with integrated stellar feature of Mgb. For 28
galaxies, the best-fit $M_{bh}$-Mgb relation has a small scatter, which is an
equivalent level with other well-known relation, such as a correlation between
the stellar velocity dispersion and the mass. An averaged iron index $<$Fe$>$
also positively correlates with $M_{bh}$, but the best-fit $M_{bh}$-$<$Fe$>$
relation has a larger scatter. The difference comes from the synthesis and
evolution mechanisms, and may be important for the SMBH and star formation
history in the host spheroid.


title: Discovery potential of the next-to-minimal supergravity-motivated model

abstract:
  Applying a likelihood analysis to the next-to-minimal supergravity-motivated
model, we identify parameter space regions preferred by present experimental
limits from collider, astrophysical, and low energy measurements. We then show
that favored regions are amenable to detection by a combination of the CERN
Large Hadron Collider and an upgraded Cryogenic Dark Matter Search, provided
that the more than three sigma discrepancy in the difference of the
experimental and the standard theoretical values of the anomalous magnetic
moment of the muon prevails in the future.


title: Electromagnetic Productions of KLambda and KSigma on the Nucleons

abstract:
  We briefly review the progress and problems in the electromagnetic production
of KLambda on the nucleon. The problem of the data discrepancy in this channel
as well as the corresponding physics consequence are highlighted. We also
discuss the effect of the new beam-recoil polarization data Cx and Cz on our
analysis. For this purpose we use the isobar model Kaon-Maid and a recent
multipoles model that can describe recent experimental data. We also present a
new multipoles model for the KSigma channels to complete our analysis.


title: Low-Density Instability of Multi-Component Matter with Trapped Neutrinos

abstract:
  The effect of neutrino trapping on the longitudinal dielectric function at
low densities has been investigated by using different relativistic mean field
models. Parameter sets G2 of Furnstahl-Serot-Tang and Z271 of
Horowitz-Piekarewicz, along with the adjusted parameter sets of both models,
have been used in this study. The role of the isovector adjustment and the
effect of the Coulomb interaction have been also studied. The effect of the
isovector adjustment is found to be more significant in the
Horowitz-Piekarewicz model, not only in the neutrinoless matter, but also in
the matter with neutrino trapping. Although almost independent to the variation
of the leptonic fraction, the instability region of matter with neutrino
trapping is found to be larger. The presence of more protons and electrons
compared to the neutrinoless case is the reason behind this finding. For
parameter sets with soft equation of states at low density, the appearance of a
large and negative epsilon_L (q, q0 = 0) in some parts of the edge of the
instability region in matter with neutrino trapping is understood as a
consequence of the fact that the Coulomb interaction produced by electrons and
protons interaction is larger than the repulsive isovector interaction created
by the asymmetry between the proton and neutron numbers.


title: A Necessary Condition for Individual Time-Steps in SPH Simulations

abstract:
  We show that the smoothed particle hydrodynamics (SPH) method, used with
individual time-steps in the way described in the literature, cannot handle
strong explosion problems correctly. In the individual time-step scheme,
particles determine their time-steps essentially from a local Courant
condition. Thus they cannot respond to a strong shock, if the pre-shock
timescale is too long compared to the shock timescale. This problem is not
severe in SPH simulations of galaxy formation with a temperature cutoff in the
cooling function at $10^4 {\rm K}$, while it is very dangerous for simulations
in which the multiphase nature of the interstellar medium under $10^4 {\rm K}$
is taken into account. A solution for this problem is to introduce a time-step
limiter which reduces the time-step of a particle if it is too long compared to
the time-steps of its neighbor particles. Thus this kind of time-step
constraint is essential for the correct treatment of explosions in
high-resolution SPH simulations with individual time-steps.


title: Elementary Techniques for Erdos-Ko-Rado-like Theorems

abstract:
  The well-known Erdos-Ko-Rado Theorem states that if F is a family of
k-element subsets of {1,2,...,n} (n>2k-1) such that every pair of elements in F
has a nonempty intersection, then |F| is at most $\binom{n-1}{k-1}$. The
theorem also provides necessary and sufficient conditions for attaining the
maximum. We present elementary methods for deriving generalizations of the
Erdos-Ko-Rado Theorem on several classes of combinatorial objects. We also
extend our results to systems under Hamming intersection.


title: R&D progress on second-generation crystals for Laue lens applications

abstract:
  The concept of a gamma-ray telescope based on a Laue lens offers the
possibility to increase the sensitivity by more than an order of magnitude with
respect to existing instruments. Laue lenses have been developed by our
collaboration for several years : the main achievement of this R&D program was
the CLAIRE lens prototype. Since then, the endeavour has been oriented towards
the development of efficient diffracting elements (crystal slabs), the aim
being to step from a technological Laue lens to a scientifically exploitable
lens. The latest mission concept featuring a gamma-ray lens is the European
Gamma-Ray Imager (GRI) which intends to make use of the Laue lens to cover
energies from 200 keV to 1300 keV.
  Investigations of two promising materials, low mosaicity copper and gradient
concentration silicon-germanium are presented in this paper. The measurements
have been performed during three runs on beamline ID15A of the European
Synchrotron Radiation Facility, and on the GAMS 4 instrument of the Institute
Laue-Langevin (both in Grenoble, France) using highly monochromatic beam of
energy close to 500 keV. Despite it was not perfectly homogeneous, the
presented copper crystal exhibits peak reflectivity of 25% in accordance with
theoretical predictions, and a mosaicity around 26 arcsec, the ideal range for
the realization of a Laue lens such as GRI. Silicon-germanium featuring a
constant gradient have been measured for the very first time at 500 keV. Two
samples showed a quite homogeneous reflectivity reaching 26%, which is far from
the 48% already observed in experimental crystals but a very encouraging
beginning. This results have been used to estimate the performance of the GRI
Laue lens design.


title:
Experimental Measurement of Lower and Upper Bounds of Concurrence for
  Mixed Quantum States

abstract:
  We experimentally measure the lower and upper bounds of concurrence for a set
of two-qubit mixed quantum states using photonic systems. The measured
concurrence bounds are in agreement with the results evaluated from the density
matrices reconstructed through quantum state tomography. In our experiment, we
propose and demonstrate a simple method to provide two faithful copies of a
two-photon mixed state required for parity measurements: Two photon pairs
generated by two neighboring pump laser pulses through optical parametric down
conversion processes represent two identical copies. This method can be
conveniently generalized for entanglement estimation of multi-photon mixed
states.


title: A Conversation with Peter Huber

abstract:
  Peter J. Huber was born on March 25, 1934, in Wohlen, a small town in the
Swiss countryside. He obtained a diploma in mathematics in 1958 and a Ph.D. in
mathematics in 1961, both from ETH Zurich. His thesis was in pure mathematics,
but he then decided to go into statistics. He spent 1961--1963 as a postdoc at
the statistics department in Berkeley where he wrote his first and most famous
paper on robust statistics, ``Robust Estimation of a Location Parameter.''
After a position as a visiting professor at Cornell University, he became a
full professor at ETH Zurich. He worked at ETH until 1978, interspersed by
visiting positions at Cornell, Yale, Princeton and Harvard. After leaving ETH,
he held professor positions at Harvard University 1978--1988, at MIT
1988--1992, and finally at the University of Bayreuth from 1992 until his
retirement in 1999. He now lives in Klosters, a village in the Grisons in the
Swiss Alps. Peter Huber has published four books and over 70 papers on
statistics and data analysis. In addition, he has written more than a dozen
papers and two books on Babylonian mathematics, astronomy and history. In 1972,
he delivered the Wald lectures. He is a fellow of the IMS, of the American
Association for the Advancement of Science, and of the American Academy of Arts
and Sciences. In 1988 he received a Humboldt Award and in 1994 an honorary
doctorate from the University of Neuch\^{a}tel. In addition to his fundamental
results in robust statistics, Peter Huber made important contributions to
computational statistics, strategies in data analysis, and applications of
statistics in fields such as crystallography, EEGs, and human growth curves.


title: Double quantum dot as detector of spin bias

abstract:
  It was proposed that a double quantum dot can be used to be a detector of
spin bias. Electron transport through a double quantum dot is investigated
theoretically when a pure spin bias is applied on two conducting leads
contacted to the quantum dot. It is found that the spin polarization in the
left and right dots may be induced spontaneously while the intra-dot levels are
located within the spin bias window and breaks the left-right symmetry of the
two quantum dots. As a result, a large current emerges. For an open external
circuit an charge bias instead of a charge current will be induced in
equilibrium, which is believed to be measurable according to the current
nanotechnology. This method may provide a practical and whole electrical
approach to detect the spin bias (or the spin current) by measuring the charge
bias or current in a double quantum dot.


title:
Two elementary proofs of the Wigner theorem on symmetry in quantum
  mechanics

abstract:
  In quantum theory, symmetry has to be defined necessarily in terms of the
family of unit rays, the state space. The theorem of Wigner asserts that a
symmetry so defined at the level of rays can always be lifted into a linear
unitary or an antilinear antiunitary operator acting on the underlying Hilbert
space. We present a proof of this theorem which is both elementary and
economical. Central to our proof is the recognition that a given Wigner
symmetry can, by post-multiplication by a unitary symmetry, be taken into
either the identity or complex conjugation. Our analysis involves a judicious
interplay between the effect a given Wigner symmetry has on certain
two-dimensional subspaces and the effect it has on the entire Hilbert space.


title: LLE with low-dimensional neighborhood representation

abstract:
  The local linear embedding algorithm (LLE) is a non-linear dimension-reducing
technique, widely used due to its computational simplicity and intuitive
approach. LLE first linearly reconstructs each input point from its nearest
neighbors and then preserves these neighborhood relations in the
low-dimensional embedding. We show that the reconstruction weights computed by
LLE capture the high-dimensional structure of the neighborhoods, and not the
low-dimensional manifold structure. Consequently, the weight vectors are highly
sensitive to noise. Moreover, this causes LLE to converge to a linear
projection of the input, as opposed to its non-linear embedding goal. To
overcome both of these problems, we propose to compute the weight vectors using
a low-dimensional neighborhood representation. We prove theoretically that this
straightforward and computationally simple modification of LLE reduces LLE's
sensitivity to noise. This modification also removes the need for
regularization when the number of neighbors is larger than the dimension of the
input. We present numerical examples demonstrating both the perturbation and
linear projection problems, and the improved outputs using the low-dimensional
neighborhood representation.


title:
The Early Statistical Years: 1947--1967 A Conversation with Howard
  Raiffa

abstract:
  Howard Raiffa earned his bachelor's degree in mathematics, his master's
degree in statistics and his Ph.D. in mathematics at the University of
Michigan. Since 1957, Raiffa has been a member of the faculty at Harvard
University, where he is now the Frank P. Ramsey Chair in Managerial Economics
(Emeritus) in the Graduate School of Business Administration and the Kennedy
School of Government. A pioneer in the creation of the field known as decision
analysis, his research interests span statistical decision theory, game theory,
behavioral decision theory, risk analysis and negotiation analysis. Raiffa has
supervised more than 90 doctoral dissertations and written 11 books. His new
book is Negotiation Analysis: The Science and Art of Collaborative Decision
Making. Another book, Smart Choices, co-authored with his former doctoral
students John Hammond and Ralph Keeney, was the CPR (formerly known as the
Center for Public Resources) Institute for Dispute Resolution Book of the Year
in 1998. Raiffa helped to create the International Institute for Applied
Systems Analysis and he later became its first Director, serving in that
capacity from 1972 to 1975. His many honors and awards include the
Distinguished Contribution Award from the Society of Risk Analysis; the Frank
P. Ramsey Medal for outstanding contributions to the field of decision analysis
from the Operations Research Society of America; and the Melamed Prize from the
University of Chicago Business School for The Art and Science of Negotiation.
He earned a Gold Medal from the International Association for Conflict
Management and a Lifetime Achievement Award from the CPR Institute for Dispute
Resolution. He holds honorary doctor's degrees from Carnegie Mellon University,
the University of Michigan, Northwestern University, Ben Gurion University of
the Negev and Harvard University. The latter was awarded in 2002.


title: Comment on "Learning to Build the Bomb"

abstract:
  According to Alisa Carrigan's opinion in Physics Today Dec 2007, to prevent
proliferation of nuclear weapons, certain rules should be set to prevent the
spread of a particular kind of knowledge. Here, I argue that a knowledge
blockade does not work, and it is not a suitable means to establish a
sustainable peace.


title:
Growth rate and extinction rate of a reaction diffusion equation with a
  singular nonlinearity

abstract:
  We prove the growth rate of global solutions of the equation $u_t=\Delta
u-u^{-\nu}$ in $\R^n\times (0,\infty)$, $u(x,0)=u_0>0$ in $\R^n$, where $\nu>0$
is a constant. More precisely for any $0<u_0\in C(\R^n)$ satisfying
$A_1(1+|x|^2)^{\alpha_1}\le u_0\le A_2(1+|x|^2)^{\alpha_2}$ in $\R^n$ for some
constants $1/(1+\nu)\le\alpha_1<1$, $\alpha_2\ge\alpha_1$ and $A_2\ge A_1=
(2\alpha_1(1-\3)(n+2\alpha_1-2))^{-1/(1+\nu)}$ where $0<\3<1$ is a constant,
the global solution $u$ exists and satisfies $A_1(1+|x|^2+b_1t)^{\alpha_1}\le
u(x,t)\le A_2(1+|x|^2+b_2t)^{\alpha_2}$ in $\R^n\times (0,\infty)$ where
$b_1=2(n+2\alpha_1-2)\3$ and $b_2=2n$ if $0<\alpha_2\le 1$ and
$b_2=2(n+2\alpha_2-2)$ if $\alpha_2>1$. We also find various conditions on the
initial value for the solution to extinct in a finite time and obtain the
corresponding decay rate of the solution near the extinction time.


title: Spin Nernst effect and Nernst effect in two-dimensional electron systems

abstract:
  We study the Nernst effect and the spin Nernst effect, that a longitudinal
thermal gradient induces a transverse voltage and a spin current. A mesoscopic
four-terminal cross-bar device having the Rashba spin-orbit interaction (SOI)
under a perpendicular magnetic field is considered. For zero SOI, the Nernst
coefficient peaks when the Fermi level crosses the Landau Levels. In the
presence of the SOI, the Nernst peaks split, and the spin Nernst effect appears
and exhibits a series of oscillatory structures. The larger SOI is or the
weaker magnetic field is, the more pronounced the spin Nernst effect is. The
results also show that the Nernst and spin Nernst coefficients are sensitive to
the detailed characteristics of the sample and the contacts. In addition, the
Nernst effect is found to survive in strong disorder than the spin Nernst
effect does.


title: Chevalley Supergroups

abstract:
  In the framework of algebraic supergeometry, we give a construction of the
scheme-theoretic supergeometric analogue of Chevalley groups, namely affine
algebraic supergroups associated to simple Lie superalgebras of classical type.
In particular both basic (even exceptional) and strange cases are covered.
  This provides a unified approach to most of the algebraic supergroups
considered so far in literature, and an effective method to construct new ones.
  As an intermediate step, we prove an existence theorem for Chevalley bases of
simple classical Lie superalgebras and a PBW-like theorem for their associated
Kostant superalgebras.


title: Ab-initio band structure of doped graphene

abstract:
  We present an \emph{ab-initio} study of the graphene quasi-particle band
structure as function of the doping in G_0 W_0 approximation. We show that the
LDA Fermi velocity is substantially renormalized and this renormalization
rapidly decreases as function of the doping. We found, in agreement with
previous papers, that close to the Dirac point the linear dispersion of the
bands is broken but this behaviour disappears with a small doping. We discuss
our results in the light of recent experiments on graphene and intercalate
graphite.


title: Relative Yamabe invariant and c-concordant metrics

abstract:
  We show a surgery formula for the relative Yamabe invariant and give
applications to the study of concordance classes of metrics.


title: A complex-angle rotation and geometric complementarity in fermion mixing

abstract:
  The mixing among flavors in quarks or leptons in terms of a single rotation
angle is defined such that three flavor eigenvectors are transformed into three
mass eigenvectors by a single rotation about a common axis. We propose that a
geometric complementarity condition exists between the complex angle of quarks
and that of leptons in $\mathbb{C}^2$ space. The complementarity constraint has
its rise in quark-lepton unification and is reduced to the correlation among
$\theta_{12}, \theta_{23}, \theta_{13}$ and the CP phase $\delta$. The CP phase
turns out to have a non-trivial dependence on all the other angles. We will
show that further precise measurements in real angles can narrow down the
allowed region of $\delta$. In comparison with other complementarity schemes,
this geometric one can avoid the problem of the $\theta_{13}$ exception and can
naturally keep the lepton basis being independent of quark basis.


title: On positivity in algebras of tempered generalized functions

abstract:
  An explicit counterexample shows that contrary to the situation in the
special Colombeau algebra, positivity and invertibility cannot be characterized
pointwise in algebras of tempered generalized functions. Further a point value
characterization of the latter is refined.


title: Nuclear structure of Ac-231

abstract:
  The low-energy structure of 231Ac has been investigated by means of gamma ray
spectroscopy following the beta-decay of 231Ra. Multipolarities of 28
transitions have been established by measuring conversion electrons with a
mini-orange electron spectrometer. The decay scheme of 231Ra --> 231Ac has been
constructed for the first time. The Advanced Time Delayed beta-gamma-gamma(t)
method has been used to measure the half-lives of five levels. The moderately
fast B(E1) transition rates derived suggest that the octupole effects, albeit
weak, are still present in this exotic nucleus.


title: Knotted holomorphic discs in C^2

abstract: We construct knotted proper holomorphic embeddings of the unit disc in C^2.


title: Selected Items in Jet Algorithms

abstract:
  I provide a very brief overview of recent developments in jet algorithms,
mostly focusing on the issue of infrared-safety.


title:
Self-Regulated Fueling of Galaxy Centers: Evidence for Star-Formation
  Feedback in IC342's Nucleus

abstract:
  Using new, high-resolution interferometric observations of the CO and HCN
molecules, we directly compare the molecular and ionized components of the
interstellar medium in the center of the nearby spiral galaxy IC342, on spatial
scales of ~ 10pc. The morphology of the tracers suggests that the molecular gas
flow caused by a large-scale stellar bar has been strongly affected by the
mechanical feedback from recent star formation activity within the central
100pc in the nucleus of the galaxy. Possibly, stellar winds and/or supernova
shocks originating in the nuclear star cluster have compressed, and likely
pushed outward, the infalling molecular gas, thus significantly reducing the
gas supply to the central 10pc. Although our analysis currently lacks kinematic
confirmation due to the face-on orientation of IC342, the described scenario is
supported by the generally observed repetitive nature of star formation in the
nuclear star clusters of late-type spiral galaxies.


title: Understanding photonic quantum-logic gates: The road to fault tolerance

abstract:
  Fault-tolerant quantum computing requires gates which function correctly
despite the presence of errors, and are scalable if the error
probability-per-gate is below a threshold value. To date, no method has been
described for calculating this probability from measurements on a gate. Here we
introduce a technique enabling quantitative benchmarking of quantum-logic gates
against fault-tolerance thresholds for any architecture. We demonstrate our
technique experimentally using a photonic entangling-gate. The relationship
between experimental errors and their quantum logic effect is non-trivial:
revealing this relationship requires a comprehensive theoretical model of the
quantum-logic gate. We show the first such model for any architecture, and find
multi-photon emission--a small effect previously regarded as secondary to
mode-mismatch--to be the dominant source of logic error. We show that reducing
this will move photonic quantum computing to within striking distance of
fault-tolerance.


title:
A discrete element study of settlement in vibrated granular layers: role
  of contact loss and acceleration

abstract:
  This paper deals with the vibration of granular materials due to cyclic
external excitation. It highlights the effect of the acceleration on the
settlement speed and proves the existence of a relationship between settlement
and loss of contacts in partially confined granular materials under vibration.
The numerical simulations are carried out using the Molecular Dynamics method,
where the discrete elements consist of polygonal grains. The data analyses are
conducted based on multivariate autoregressive models to describe the
settlement and permanent contacts number with respect to the number of loading
cycles.


title:
Experimental and theoretical studies of sequence effects on the
  fluctuation and melting of short DNA molecules

abstract:
  Understanding the melting of short DNA sequences probes DNA at the scale of
the genetic code and raises questions which are very different from those posed
by very long sequences, which have been extensively studied. We investigate
this problem by combining experiments and theory. A new experimental method
allows us to make a mapping of the opening of the guanines along the sequence
as a function of temperature. The results indicate that non-local effects may
be important in DNA because an AT-rich region is able to influence the opening
of a base pair which is about 10 base pairs away. An earlier mesoscopic model
of DNA is modified to correctly describe the time scales associated to the
opening of individual base pairs well below melting, and to properly take into
account the sequence. Using this model to analyze some characteristic sequences
for which detailed experimental data on the melting is available [Montrichok et
al. 2003 Europhys. Lett. {\bf 62} 452], we show that we have to introduce
non-local effects of AT-rich regions to get acceptable results. This brings a
second indication that the influence of these highly fluctuating regions of DNA
on their neighborhood can extend to some distance.


title: Measurements of ttbar production cross-section with D0 experiment

abstract:
  The recent measurements of the top anti-top quark pair production
cross-section in proton antiproton collisions at sqrt{s}=1.96 TeV in lepton +
jets and dilepton (including tau lepton) channels are presented. These
measurements are based on 1 fb^{-1} of data collected with the DO experiment at
the Fermilab Tevatron collider. The measured values are compatible with the
standard model prediction and have the uncertainty close to the uncertainty of
the theoretical prediction ~10%.


title:
Physical understanding of an echo-Doppler test with voice-induced
  vibration

abstract:
  The physical understanding of a method of detecting mammalian cancer via
vocalization during a normal echo-Doppler test is provided. The backscattered
ultrasound frequency in the case of a vocal humming resonating in the chest
wall is computed: the overall effect is that the signal/noise ratio could be
easily improved at no cost. Clinical results are to appear separately
elsewhere.


title: Modelling DNA at the mesoscale: a challenge for nonlinear science?

abstract:
  When it is viewed at the scale of a base pair, DNA appears as a nonlinear
lattice. Modelling its properties is a fascinating goal. The detailed
experiments that can be performed on this system impose constraints on the
models and can be used as a guide to improve them. There are nevertheless many
open problems, particularly to describe DNA at the scale of a few tens of base
pairs, which is relevant for many biological phenomena.


title: Sub-barrier fusion excitation for the system $^7$Li+$^{28}$Si

abstract:
  The sub-barrier fusion excitation functions are measured for the first time
for the system $^7$Li +$^{28}$Si by the characteristic $\gamma$-ray method in
the energy range $E_{lab}$= 7-11.5 MeV. The results show an enhancement, below
the barrier, by about a factor of two when compared with the one-dimensional
barrier penetration (1D BPM) model. Introduction of coupling with the
rotational 2$^{+}$ state (1.779MeV) of the target improves the fit somewhat,
but still an enhancement of about 25-40% remains.


title:
Backward stochastic variational inequalities with locally bounded
  generators

abstract:
  The paper deals with the existence and uniqueness of the solution of the
backward stochastic variational inequality: \begin{equation}
\left\{\begin{array} {l}-dY_{t}+\partial \varphi(Y_{t})dt \ni
F(t,Y_{t},Z_{t})dt-Z_{t}dB_{t},\;0\leq t<T \\ Y_{T}=\eta, \end{array}
\right.\end{equation} where $F$ satisfies a local boundedness condition.


title:
Identification of Nodal Kink in Electron-Doped
  (Nd$_{1.85}$Ce$_{0.15}$)CuO$_4$ Superconductor from Laser-Based
  Angle-Resolved Photoemission Spectroscopy

abstract:
  High-resolution laser-based angle-resolved photoemission measurements have
been carried out on the electron-doped (Nd$_{1.85}$Ce$_{0.15}$)CuO$_4$ high
temperature superconductor. We have revealed a clear kink at $\sim$60 meV in
the dispersion along the (0,0)-($\pi$,$\pi$) nodal direction, accompanied by a
peak-dip-hump feature in the photoemission spectra. This indicates that the
nodal electrons are coupled to collective excitations (bosons) in
electron-doped superconductors, with the phonons as the most likely candidate
of the boson. This finding has established a universality of nodal electron
coupling in both hole- and electron-doped high temperature cuprate
superconductors.


title:
On the Question of Temperature Transformations under Lorentz and Galilei
  Boosts

abstract:
  We provide a quantum statistical thermodynamical solution of the long
standing problem of temperature transformations of uniformly moving bodies. Our
treatment of this question is based on the well established quantum statistical
result that the thermal equilibrium conditions demanded by both the Zeroth and
Second Laws of Thermodynamics are precisely those of Kubo, Martin and Schwinger
(KMS). We prove that, in both the special relativistic and nonrelativistic
settings, a state of a body cannot satisfy these conditions for different
inertial frames with non-zero relative velocity. Hence a body that serves as a
thermal reservoir, in the sense of the Zeroth Law, in an inertial rest frame
cannot do so in a laboratory frame relative to which it moves with non-zero
uniform velocity. Consequently, there is no law of temperature transformation
under either Lorentz or Galilei boosts, and so the concept of temperature
stemming from the Zeroth Law is restricted to states of bodies in their rest
frames.


title:
Granularity and vortex dynamics in LaO_0.92F_0.08FeAs as probed by
  harmonics of the AC magnetic susceptibility

abstract:
  Fundamental and higher harmonics of the AC magnetic susceptibility have been
measured on a LaO_0.92F_0.08FeAs sample as a function of the temperature, at
various amplitudes and frequencies of the AC magnetic field, with a small
superimposed DC field parallel to the AC field. The granularity of the sample
has been investigated and the inter-grain and intra-grain contributions have
been clearly individuated looking at both the first and third harmonics. The
vortex dynamics has been also analyzed, and a comparison with the magnetic
behavior of both the MgB_2 and the cuprate superconductors has been performed.
Some vortex dissipative phenomena, i.e. the thermally activated flux flow and
the flux creep, have been detected in the presented measurements, similar to
what obtained on YBCO. Nevertheless, although the general behavior is similar,
several differences have been also evidenced between these different classes of
superconductors, mainly in the third harmonics. We infer that different vortex
dynamics have to be included into the analysis of the magnetic response in this
iron-based new material.