title: Fibers of Generic Projections

abstract:
  Let X be a smooth projective variety of dimension n in P^r. We study the
fibers of a general linear projection pi: X --> P^{n+c}, with c > 0. When n is
small it is classical that the degree of any fiber is bounded by n/c+1, but
this fails for n >> 0. We describe a new invariant of the fiber that agrees
with the degree in many cases and is always bounded by n/c+1. This implies, for
example, that if we write a fiber as the disjoint union of schemes Y' and Y''
such that Y' is the union of the locally complete intersection components of Y,
then deg Y'+deg Y''_red <= n/c+1 and this formula can be strengthened a little
further. Our method also gives a sharp bound on the subvariety of P^r swept out
by the l-secant lines of X for any positive integer l, and we discuss a
corresponding bound for highly secant linear spaces of higher dimension. These
results extend Ziv Ran's "Dimension+2 Secant Lemma".


title:
Radiative Efficiency and Content of Extragalactic Radio Sources: Toward
  a Universal Scaling Relation Between Jet Power and Radio Power

abstract:
  We present an analysis of the energetics and particle content of the lobes of
24 radio galaxies at the cores of cooling clusters. The radio lobes in these
systems have created visible cavities in the surrounding hot, X-ray-emitting
gas, which allow direct measurement of the mechanical jet power of radio
sources over six decades of radio luminosity, independently of the radio
properties themselves. Using these measurements, we examine the ratio between
radio power and total jet power (the radiative efficiency). We find that jet
(cavity) power increases with radio synchrotron power approximately as P_jet ~
(L_radio)^beta, where 0.35 < beta < 0.70 depending on the bandpass of
measurement and state of the source. However, the scatter about these relations
caused by variations in radiative efficiency spans more than four orders of
magnitude. After accounting for variations in synchrotron break frequency
(age), the scatter is reduced by ~ 50%, yielding the most accurate scaling
relation available between the lobe bolometric radio power and the jet (cavity)
power. We place limits on the magnetic field strengths and particle content of
the radio lobes using a variety of X-ray constraints. We find that the lobe
magnetic field strengths vary between a few to several tens of microgauss
depending on the age and dynamical state of the lobes. If the cavities are
maintained in pressure balance with their surroundings and are supported by
internal fields and particles in equipartition, the ratio of energy in
electrons to heavy particles (k) must vary widely from approximately unity to
4000, consistent with heavy (hadronic) jets.


title:
Investigating Off-shell Stability of Anti-de Sitter Space in String
  Theory

abstract:
  We propose an investigation of stability of vacua in string theory by
studying their stability with respect to a (suitable) world-sheet
renormalization group (RG) flow. We prove geometric stability of (Euclidean)
anti-de Sitter (AdS) space (i.e., $\mathbf{H}^n$) with respect to the simplest
RG flow in closed string theory, the Ricci flow. AdS space is not a fixed point
of Ricci flow. We therefore choose an appropriate flow for which it is a fixed
point, prove a linear stability result for AdS space with respect to this flow,
and then show this implies its geometric stability with respect to Ricci flow.
The techniques used can be generalized to RG flows involving other fields. We
also discuss tools from the mathematics of geometric flows that can be used to
study stability of string vacua.


title: Information-Theoretically Secure Voting Without an Honest Majority

abstract:
  We present three voting protocols with unconditional privacy and
information-theoretic correctness, without assuming any bound on the number of
corrupt voters or voting authorities. All protocols have polynomial complexity
and require private channels and a simultaneous broadcast channel. Our first
protocol is a basic voting scheme which allows voters to interact in order to
compute the tally. Privacy of the ballot is unconditional, but any voter can
cause the protocol to fail, in which case information about the tally may
nevertheless transpire. Our second protocol introduces voting authorities which
allow the implementation of the first protocol, while reducing the interaction
and limiting it to be only between voters and authorities and among the
authorities themselves. The simultaneous broadcast is also limited to the
authorities. As long as a single authority is honest, the privacy is
unconditional, however, a single corrupt authority or a single corrupt voter
can cause the protocol to fail. Our final protocol provides a safeguard against
corrupt voters by enabling a verification technique to allow the authorities to
revoke incorrect votes. We also discuss the implementation of a simultaneous
broadcast channel with the use of temporary computational assumptions, yielding
versions of our protocols achieving everlasting security.


title: Single Spin Asymmetries in Heavy Quark and Antiquark Productions

abstract:
  The single transverse spin asymmetries in heavy quark and anti-quark
production from the quark-antiquark annihilation channel contribution is
studied by taking into account the initial and final state interactions
effects. Because of the different color charges, the final state interaction
effects lead to about a factor of 3 difference in the spin asymmetry for heavy
quark over that for the anti-quark in the valence region of low energy pp
collisions. The experimental study of this model-independent prediction shall
provide a crucial test for the underlying mechanism for the single spin
asymmetry phenomena.


title: On superconducting and magnetic properties of iron-oxypnictides

abstract:
  Pairing symmetry in oxypnictides, a new family of multiband high-Tc
superconductors, is partially imposed by the positions of multiple Fermi
pockets, which itself can give rise to new order parameters, such as s+,-
states or the state of dx^2-y^2 symmetry. Other pairing states may appear on
small pockets for long range interactions, but they are expected to be
sensitive to defects. We identify the competing antiferromagnetic order with
the triplet exciton transition in the semi- metallic background and discuss
whether its coexistence with superconductivity explains the doping dependence
of Tc.


title: Variable slip coefficient in binary lattice Boltzmann models

abstract:
  We present a new method in order to get variable slip coefficient in binary
lattice Boltzmann models to simulate gaseous flows. Boundary layer theory is
presented. We study both the single- and multi-fluid BGK-type models as well.
The boundary slip and the Knudsen layer are analyzed in detail. Benchmark
simulations are carried out in order to compare the analytical derivation with
the numerical results. Excellent agreement is found between the two situations.


title: Algebraic density property of homogeneous spaces

abstract:
  Let $X$ be an affine algebraic variety with a transitive action of the
algebraic automorphism group. Suppose that $X$ is equipped with several
non-degenerate fixed point free $SL_2$-actions satisfying some mild additional
assumption. Then we show that the Lie algebra generated by completely
integrable algebraic vector fields on $X$ coincides with the set of all
algebraic vector fields. In particular, we show that apart from a few
exceptions this fact is true for any homogeneous space of form $G/R$ where $G$
is a linear algebraic group and $R$ is its proper reductive subgroup.


title:
Current status of Dirac-Brueckner-Hartree-Fock calculations in
  asymmetric nuclear matter

abstract:
  We review the current status of our microscopic calculations in asymmetric
nuclear matter. Updated predictions of the equation of state are made available
to potential users. We discuss the features of our EoS in relation to the
predicted neutron star maximum masses.


title:
Energy dependence of phi meson production in central Pb+Pb collisions at
  sqrt(s_nn) = 6 to 17 GeV

abstract:
  Phi meson production is studied by the NA49 Collaboration in central Pb+Pb
collisions at 20A, 30A, 40A, 80A and 158A GeV beam energy. The data are
compared with measurements at lower and higher energies and to microscopic and
thermal models. The energy dependence of yields and spectral distributions is
compatible with the assumption that partonic degrees of freedom set in at low
SPS energies.


title:
Effects of Magnetic Fields on the Diskoseismic Modes of Accreting Black
  Holes

abstract:
  The origin of the rapid quasi-periodic variabilities observed in a number of
accreting black hole X-ray binaries is not understood. It has been suggested
that these variabilities are associated with diskoseismic oscillation modes of
the black hole accretion disk. In particular, in a disk with no magnetic field,
the so-called g-modes (inertial oscillations) can be self-trapped at the inner
region of the disk due to general relativistic effects. Real accretion disks,
however, are expected to be turbulent and contain appreciable magnetic fields.
We show in this paper that even a weak magnetic field (with the magnetic energy
much less than the thermal energy) can modify or "destroy" the self-trapping
zone of disk g-modes, rendering their existence questionable in realistic black
hole accretion disks. The so-called corrugation modes (c-modes) are also
strongly affected when the poloidal field approaches equal-partition. On the
other hand, acoustic oscillations (p-modes), which do not have vertical
structure, are not affected qualitatively by the magnetic field, and therefore
may survive in a turbulent, magnetic disk.


title: Excited-state spectroscopy using single-spin manipulation in diamond

abstract:
  We use single-spin resonant spectroscopy to study the spin structure in the
orbital excited-state of a diamond nitrogen-vacancy center at room temperature.
We find that the excited state spin levels have a zero-field splitting that is
approximately half of the value of the ground state levels, a g-factor similar
to the ground state value, and a hyperfine splitting ~20x larger than in the
ground state. In addition, the width of the resonances reflects the electronic
lifetime in the excited state. We also show that the spin-splitting can
significantly differ between NV centers, likely due to the effects of local
strain, which provides a pathway to control over the spin Hamiltonian and may
be useful for quantum information processing.


title:
Borchers' Commutation Relations for Sectors with Braid Group Statistics
  in Low Dimensions

abstract:
  Borchers has shown that in a translation covariant vacuum representation of a
theory of local observables with positive energy the following holds: The
(Tomita) modular objects associated with the observable algebra of a fixed
wedge region give rise to a representation of the subgroup of the Poincare
group generated by the boosts and the reflection associated to the wedge, and
the translations. We prove here that Borchers' theorem also holds in charged
sectors with (possibly non-Abelian) braid group statistics in low space-time
dimensions. Our result is a crucial step towards the Bisognano-Wichmann theorem
for Plektons in d=3, namely that the mentioned modular objects generate a
representation of the proper Poincare group, including a CPT operator. Our main
assumptions are Haag duality of the observable algebra, and translation
covariance with positive energy as well as finite statistics of the sector
under consideration.


title: Dimer lambda_d Expansion, Dimensional Dependence of J_n Kernels

abstract:
  In previous papers an asymptotic expansion for the dimer lambda_d of the form
lambda_d ~ (1/2)ln(2d) - 1/2 + c_1/d + c_2/d^2 ... was developed. Kernels J_n
were a key ingredient in the theory. Herein we prove J_n are of the form J_n =
C_r/d^r + C_(r+1)/d^(r+1) + ... + C_(n-1)/d^(n-1) with r > (n/2)-1.


title:
A Fiber Approach to Harmonic Analysis of Unfolded Higher-Spin Field
  Equations

abstract:
  In Vasiliev's unfolded formulation of higher-spin dynamics the standard
fields are embedded on-shell into covariantly constant master fields valued in
Lorentz-covariant slices of the star-product algebra A of functions on the
singleton phase space. Correspondingly, the harmonic expansion is taken over
compact slices of A that are unitarizable in a rescaled trace-norm rather than
the standard Killing norm. Motivated by the higher-derivative nature of the
theory, we examine indecomposable unitarizable Harish-Chandra modules
consisting of standard massless particles plus linearized runaway solutions.
This extension arises naturally in the above fiber approach upon realizing
compact-weight states as non-polynomial analytic functions in A.


title: A New Unconventional Antiferromagnet, Yb$_3$Pt$_4$

abstract:
  We report the synthesis and basic properties of single crystals of a new
binary compound, Yb$_{3}$Pt$_{4}$. The Yb ions in this compound are fully
trivalent, and heat capacity measurements show that the crystal field scheme
involves a doublet ground state, well separated from the excited states, which
are fully occupied above $\sim$ 150 K. The heat capacity displays a large,
weakly first order anomaly at 2.4 K, where a cusp is observed in the magnetic
susceptibility signalling the onset of antiferromagnetic order. The entropy
associated with this order is the full Rln2 of the doublet ground state,
however the magnetic susceptibility in the ordered phase is dominated by a
large and temperature independent component below the Neel temperature. The
heat capacity in the ordered state originates with ferromagnetic spin waves,
giving evidence for the inherently local moment character of the ordered state.
The electrical resistivity is unusually large, and becomes quadratic in
temperature exactly at the Neel temperature. The absence of analogous Fermi
liquid behavior in the heat capacity and the magnetic susceptibility implies
that Yb$_{3}$Pt$_{4}$ is a low electron density system, where the Fermi surface
is further gapped by the onset of magnetic order.


title:
Fermionic vacuum polarization by a composite topological defect in
  higher-dimensional space-time

abstract:
  We investigate the vacuum polarization effects associated with a charged
massless spin-1/2 field in a higher-dimensional space-time, induced by a
composite topological defect. The defect is constituted by a global monopole
living on a three-brane and two-dimensional conical space transverse to the
latter. In addition, we assume the presence of an extra magnetic flux along the
core of the conical space. The heat kernel and the Feynman Green function are
presented in the form of a sum of two terms. The first one corresponds to the
contribution coming from the bulk with global monopole in the absence of
conical structure of the orthogonal two-space, and the second one is induced by
this structure and the magnetic flux. We explicitly evaluate the part in the
vacuum expectation value of the energy-momentum tensor induced by the flux
carrying conical structure. As in pure cosmic string geometries, only the
fractional part of the ratio of the magnetic flux to flux quantum leads to
non-trivial effects. The vacuum energy-momentum tensor is an even function of
this parameter. We show that for strong gravitational fields corresponding to
large values of the solid angle deficit, the effects induced by the conical
structure and flux are exponentially suppressed.


title: Complexity in atoms: an approach with a new analytical density

abstract:
  In this work, the calculation of complexity on atomic systems is considered.
In order to unveil the increasing of this statistical magnitude with the atomic
number due to the relativistic effects, recently reported in [A. Borgoo, F. De
Proft, P. Geerlings, K.D. Sen, Chem. Phys. Lett., 444 (2007) 186], a new
analytical density to describe neutral atoms is proposed. This density is
inspired in the Tietz potential model. The parameters of this density are
determined from the normalization condition and from a variational calculation
of the energy, which is a functional of the density. The density is
non-singular at the origin and its specific form is selected so as to fit the
results coming from non-relativistic Hartree-Fock calculations. The main
ingredients of the energy functional are the non-relativistic kinetic energy,
the nuclear-electron attraction energy and the classical term of the electron
repulsion. The relativistic correction to the kinetic energy and the Weizsacker
term are also taken into account. The Dirac and the correlation terms are shown
to be less important than the other terms and they have been discarded in this
study. When the statistical measure of complexity is calculated in position
space with the analytical density derived from this model, the increasing trend
of this magnitude as the atomic number increases is also found.

categories: nlin.CD cs.IT math.IT physics.atom-ph quant-ph


title: Semitoric integrable systems on symplectic 4-manifolds

abstract:
  Let M be a symplectic 4-manifold. A semitoric integrable system on M is a
pair of real-valued smooth functions J, H on M for which J generates a
Hamiltonian S^1-action and the Poisson brackets {J,H} vanish. We shall
introduce new global symplectic invariants for these systems; some of these
invariants encode topological or geometric aspects, while others encode
analytical information about the singularities and how they stand with respect
to the system. Our goal is to prove that a semitoric system is completely
determined by the invariants we introduce.


title:
On a heuristic point of view related to quantum nonequilibrium
  statistical mechanics

abstract:
  In this paper I propose a new way for counting the microstates of a system
out of equilibrium. As, according to quantum mechanics, things happen as if a
given particle can be found in more than one state at once, I extend this
concept to propose the coherent access by a particle to the available states of
a system. By coherent access I mean the possibility for the particle to act as
if it is populating more than one microstate at once. This hypothesis has
experimental implications, since the thermodynamical probability and, as a
consequence, the Bose-Einstein distribution as well as the argument of the
Boltzmann factor is modified.


title: Tight Bounds for Hashing Block Sources

abstract:
  It is known that if a 2-universal hash function $H$ is applied to elements of
a {\em block source} $(X_1,...,X_T)$, where each item $X_i$ has enough
min-entropy conditioned on the previous items, then the output distribution
$(H,H(X_1),...,H(X_T))$ will be ``close'' to the uniform distribution. We
provide improved bounds on how much min-entropy per item is required for this
to hold, both when we ask that the output be close to uniform in statistical
distance and when we only ask that it be statistically close to a distribution
with small collision probability. In both cases, we reduce the dependence of
the min-entropy on the number $T$ of items from $2\log T$ in previous work to
$\log T$, which we show to be optimal. This leads to corresponding improvements
to the recent results of Mitzenmacher and Vadhan (SODA `08) on the analysis of
hashing-based algorithms and data structures when the data items come from a
block source.


title: Stochastic processes in turbulent transport

abstract:
  This is a set of four lectures devoted to simple ideas about turbulent
transport, a ubiquitous non-equilibrium phenomenon. In the course similar to
that given by the author in 2006 in Warwick [45], we discuss lessons which have
been learned from naive models of turbulent mixing that employ simple random
velocity ensembles and study related stochastic processes. In the first
lecture, after a brief reminder of the turbulence phenomenology, we describe
the intimate relation between the passive advection of particles and fields by
hydrodynamical flows. The second lecture is devoted to some useful tools of the
multiplicative ergodic theory for random dynamical systems. In the third
lecture, we apply these tools to the example of particle flows in the Kraichnan
ensemble of smooth velocities that mimics turbulence at intermediate Reynolds
numbers. In the fourth lecture, we extends the discussion of particle flows to
the case of non-smooth Kraichnan velocities that model fully developed
turbulence. We stress the unconventional aspects of particle flows that appear
in this regime and lead to phase transitions in the presence of
compressibility. The intermittency of scalar fields advected by fully turbulent
velocities and the scenario linking it to hidden statistical conservation laws
of multi-particle flows are briefly explained.


title: Non-Gaussian halo bias and future galaxy surveys

abstract:
  We forecast constraints on primordial non-Gaussianity achievable from
forthcoming surveys by exploiting the scale-dependent halo bias introduced on
large scales by non-Gaussian initial conditions. We explore the performance of
exploiting both the shape of the galaxy power-spectrum on large scales and the
cross-correlation of galaxies with Cosmic Microwave Background maps through the
Integrated Sachs Wolfe effect. We find that future surveys can detect
primordial non-Gaussianity of the local form with a non-Gaussianity parameter
$|f_{\rm NL}|$ of order unity. This is particularly exciting because, while the
simplest single-field slow-roll models of inflation predict a primordial
$|f_{\rm NL}|\ll 1$, this signal sources extra contributions to the effective
$f_{\rm NL}$ of large-scale structures that are expected to be above our
predicted detection threshold.


title: Core creation in galaxies and haloes via sinking massive objects

abstract:
  We perform a detailed investigation into the disruption of central cusps via
the transfer of energy from sinking massive objects. Constant density inner
regions form at the radius where the enclosed mass approximately matches the
mass of the infalling body. We explore parameter space using numerical
simulations and give an empirical relation for the size of the resulting core
within structures that have different initial cusp slopes. We find that
infalling bodies always stall at the edge of these newly formed cores,
experiencing no dynamical friction over many dynamical times. As applications,
we consider the resulting decrease in the dark matter annihilation flux due to
centrally destroyed cusps, and we present a new theory for the formation of
close binary nuclei -- the `stalled binary' model. We focus on one particularly
interesting binary nucleus system, the dwarf spheroidal galaxy VCC 128 which is
dark matter dominated at all radii. We show that its nuclei would rapidly
coalesce within a few million years if it has a central dark matter cusp slope
steeper than r^{-1}. However, if its initial dark matter cusp is slightly
shallower than a log slope of -0.75 at ~0.1% of the virial radius, then the
sinking nuclei naturally create a core equal to their observed separation and
stall. This is close to the log slope measured a recent billion particle CDM
halo simulation.


title: A 20 Year Radio Light Curve for the Young Supernova Remnant G1.9+0.3

abstract:
  The radio source G1.9+0.3 has recently been identified as the youngest known
Galactic supernova remnant, with a putative age of ~100 years. We present a
radio light curve for G1.9+0.3 based on 25 epochs of observation with the
Molonglo Observatory Synthesis Telescope, spanning 20 years from 1988 to 2007.
These observations are all at the same frequency (843 MHz) and comparable
resolutions (43" x 91" or 43" x 95") and cover one fifth of the estimated
lifetime of the supernova remnant. We find that the flux density has increased
at a rate of 1.22 +0.24/-0.16 per cent per year over the last two decades,
suggesting that G1.9+0.3 is undergoing a period of magnetic field
amplification.


title: Staggered Multi-Field Inflation

abstract:
  We investigate multi-field inflationary scenarios with fields that drop out
of the model in a staggered fashion. This feature is natural in certain
multi-field inflationary setups within string theory; for instance, it can
manifest itself when fields are related to tachyons that condense, or
inter-brane distances that become meaningless when branes annihilate.
Considering a separable potential, and promoting the number of fields to a
smooth time-dependent function, we derive the formalism to deal with these
models at the background and perturbed level, providing general expressions for
the scalar spectral index and the running. We recover known results of e.g. a
dynamically relaxing cosmological constant in the appropriate limits. We
further show that isocurvature perturbations are suppressed during inflation,
so that perturbations are adiabatic and nearly Gaussian. The resulting setup
might be interpreted as a novel type of warm inflation, readily implemented
within string theory and without many of the shortcomings associated with warm
inflation.
  To exemplify the applicability of the formalism we consider three concrete
models: assisted inflation with exponential potentials as a simple toy model (a
graceful exit becomes possible), inflation from multiple tachyons (a constant
decay rate of the number of fields and negligible slow roll contributions turns
out to be in good agreement with observations) and inflation from multiple
M5-branes within M-theory (a narrow stacking of branes yields a consistent
scenario).


title: Black Rings in (Anti)-deSitter space

abstract:
  We construct solutions for thin black rings in Anti-deSitter and deSitter
spacetimes using approximate methods. Black rings in AdS exist with arbitrarily
large radius and satisfy a bound |J| \leq LM, which they saturate as their
radius becomes infinitely large. For angular momentum near the maximum, they
have larger area than rotating AdS black holes. Thin black rings also exist in
deSitter space, with rotation velocities varying between zero and a maximum,
and with a radius that is always strictly below the Hubble radius. Our general
analysis allows us to include black Saturns as well, which we discuss briefly.
We present a simple physical argument why supersymmetric AdS black rings must
not be expected: they do not possess the necessary pressure to balance the AdS
potential. We discuss the possible existence or absence of `large AdS black
rings' and their implications for a dual hydrodynamic description. An analysis
of the physical properties of rotating AdS black holes is also included.


title:
Observation of Cholesterol Dissolved in Microscopic Deposits of Free
  Fatty Acids in the Lumen of an Aorta of a Mouse Model for Human
  Atherosclerosis

abstract:
  The Raman spectrum of microscopic droplets of lipid material on the lumen of
the aorta of an apolipoprotein E knock-out mouse were reported in the
proceedings of an SPIE conference. Based on the absence of the carbonyl band in
the spectrum, at that time it was determined that the spectrum represents free
fatty acids rather than triglycerides. More recent examination of the spectrum
indicates that these droplets contain dissolved cholesterol, and thus can be
used as an early indicator of the atherosclerosis process in animal models
during drug development.


title:
Large Scale Impact of the Cosmological Population of Expanding Radio
  Galaxies

abstract:
  We seek to compute the fraction of the volume of the Universe filled by
expanding cocoons of the cosmological population of radio galaxies over the
Hubble time as well as the magnetic field infused by them, in order to assess
their importance in the cosmic evolution of the Universe. Using N-body
$\Lambda$CDM simulations, radio galaxies distributed according to the observed
radio luminosity function are allowed to evolve in a cosmological volume as
using well defined prescriptions for their expansion. We find that the radio
galaxies permeate $10 - 30%$ of the total volume with $\sim 10^{-8}$ G magnetic
field by the present epoch.


title: A Dedekind Finite Borel Set

abstract:
  In this paper we prove three theorems about the theory of Borel sets in
models of ZF without any form of the axiom of choice. We prove that if B is a
G-delta-sigma set, then either B is countable or B contains a perfect subset.
Second, we prove that if the real line is the countable union of countable
sets, then there exists an F-sigma-delta set which is uncountable but contains
no perfect subset. Finally, we construct a model of ZF in which we have an
infinite Dedekind finite set of reals which is F-sigma-delta.


title: Beam diagnostics at DAFNE with fast uncooled IR detectors

abstract:
  Bunch-by-bunch longitudinal diagnostics is a key issue of modern
accelerators. To face up this challenging demand, tests of mid-IR compact
uncooled photoconductive HgCdTe detectors have been recently performed at
DAFNE. Different devices were used to monitor the emission of e- bunches. The
first experiments allowed recording of 2.7 ns long e- bunches with a FWHM of a
single pulse of about 600 ps. These results address the possibility to improve
diagnostics at DAFNE and to this purpose an exit port on a bending magnet of
the positron ring has been set-up. An HV chamber, hosting a gold-coated plane
mirror that collects and deflects the radiation through a ZnSe window, is the
front-end of this port. After the window, a simple optical layout in air allows
focusing IR radiation on different detectors. The instrumentation will allow
comparison in the sub-ns time domain between the two rings and to identify and
characterize bunch instabilities. Moreover, to improve performances tests of
new photovoltaic detectors with sub-ns response times are in progress. We will
briefly summarize the actual status of the 3+L experiment and will discuss
future applications of fast IR photovoltaic detectors and the development of
fast IR array detectors.


title:
Complex tropical localization, coamoebas, and mirror tropical
  hypersurfaces

abstract:
  We introduce in this paper the concept of tropical mirror hypersurfaces and
we prove a complex tropical localization Theorem which is a version of
Kapranov's Theorem \cite{K-00} in tropical geometry. We give a geometric and a
topological equivalence between coamoebas of complex algebraic hypersurfaces
defined by a maximally sparse polynomial and coamoebas of maximally sparse
complex tropical hypersurfaces.


title: Perturbative Super-Yang-Mills from the Topological AdS_5xS^5 Sigma Model

abstract:
  A topological sigma model based on the pure spinor formalism was recently
proposed for the small radius limit of the AdS_5xS^5 superstring. Physical
states in this model can be constructed by connecting holes on the worldsheet
with Wilson lines of the worldsheet gauge field. The contribution of these
states to the topological amplitude is claimed to reproduce the usual Feynman
diagram expansion of gauge-invariant super-Yang-Mills correlation functions.


title: Broadband frequency mode entanglement in waveguided PDC

abstract:
  We report the observation of beatings of the coincidence event rate in a
Hong-Ou-Mandel interference (HOMI) between signal and idler photons from a
parametric downconversion (PDC) process inside a multi-mode KTP waveguide. As
explanation we introduce bi-photonic states entangled in their broadband
frequency modes generated by waveguide mode triples and propose a suitable
entanglement detection scheme.


title: Spin Dependence of Dark Matter Scattering

abstract:
  New experiments designed to discover a weakly interacting dark matter (DM)
particle via spin dependent scattering can distinguish models of electroweak
symmetry breaking. The plane of spin dependent versus spin independent DM
scattering cross sections is a powerful model diagnostic. We detail
representative predictions of mSUGRA, singlet extended SM and MSSM, a new Dirac
neutrino, Littlest Higgs with T-parity (LHT) and Minimal Universal Extra
Dimensions (mUED) models. Of these models, the nMSSM has the largest spin
dependent (SD) cross section. It has a very light neutralino which would give
lower energy nuclear recoils. The Focus Point region of mSUGRA, mUED and the
right handed neutrino also predict a very large SD cross section and predict a
large signal of high energy neutrinos in the IceCube experiment from
annihilations of dark matter in the Sun. We also describe a model independent
treatment of the scattering of DM particles of different intrinsic spins.


title: On divergence form SPDEs with VMO coefficients in a half space

abstract:
  We extend several known results on solvability in the Sobolev spaces
$W^{1}_{p}$, $p\in[2,\infty)$, of SPDEs in divergence form in $\bR^{d}_{+}$ to
equations having coefficients which are discontinuous in the space variable.


title: SUSY breaking mediation by D-brane instantons

abstract:
  It is well known that D-brane instantons can generate contributions to the
effective superpotential of gauge theories living on D-branes which are
perturbatively forbidden by global U(1) symmetries. We extend this idea to
theories with supersymmetry breaking, studying the effect of D-brane instantons
stretched between the SUSY-breaking and visible sectors. Analogously to what
happens in the SUSY case, this mechanism can give rise to perturbatively
forbidden soft terms (among other effects). We introduce and discuss general
properties of instanton mediation. We illustrate our ideas in simple Type IIB
toroidal orientifolds. As a bi-product, we present a string theory realization
of a Polonyi hidden sector.


title:
Dynamic light scattering study on phase separation of a protein-water
  mixture: Application on cold cataract development in the ocular lens

abstract:
  We present a detailed dynamic light scattering study on the phase separation
in the ocular lens emerging during cold cataract development. Cold cataract is
a phase separation effect that proceeds via spinodal decomposition of the lens
cytoplasm with cooling. Intensity auto-correlation functions of the lens
protein content are analyzed with the aid of two methods providing information
on the populations and dynamics of the scattering elements associated with cold
cataract. It is found that the temperature dependence of many measurable
parameters changes appreciably at the characteristic temperature ~16+1 oC which
is associated with the onset of cold cataract. Extending the temperature range
of this work to previously inaccessible regimes, i.e. well below the phase
separation or coexistence curve at Tcc, we have been able to accurately
determine the temperature dependence of the collective and self-diffusion
coefficient of proteins near the spinodal. The analysis showed that the
dynamics of proteins bears some resemblance to the dynamics of structural
glasses where the apparent activation energy for particle diffusion increases
below Tcc indicating a highly cooperative motion. Application of ideas
developed for studying the critical dynamics of binary protein/solvent
mixtures, as well as the use of a modified Arrhenius equation, enabled us to
estimate the spinodal temperature Tsp of the lens nucleus. The applicability of
dynamic light scattering as a non-invasive, early-diagnostic tool for ocular
diseases is also demonstrated in the light of the findings of the present
paper.


title:
Carrier multiplication yields in PbS and PbSe nanocrystals measured by
  transient photoluminescence

abstract:
  We report here an assessment of carrier multiplication (CM) yields in PbSe
and PbS nanocrystals (NCs) by a quantitative analysis of biexciton and exciton
dynamics in transient photoluminescence decays. Interest in CM, the generation
of more than one electron and hole in a semiconductor after absorption of one
photon, has renewed in recent years because of reports suggesting greatly
increased efficiencies in nanocrystalline materials compared to the bulk form,
in which CM was otherwise too weak to be of consequence in photovoltaic energy
conversion devices. In our PbSe and PbS NC samples, however, we estimate using
transient photoluminescence that at most 0.25 additional e-h pairs are
generated per photon even at energies hv > 5Eg, instead of the much higher
values reported in the literature. We argue by comparing NC CM estimates and
reported bulk values on an absolute energy basis, which we justify as
appropriate on physical grounds, that the data reported thus far are
inconclusive with respect to the importance of nanoscale-specific phenomena in
the CM process.


title:
Combining weak and strong cluster lensing: Applications to simulations
  and MS 2137

abstract:
  AIMS. While weak lensing cannot resolve cluster cores and strong lensing is
almost insensitive to density profiles outside the scale radius, combinations
of both effects promise to constrain density profiles of galaxy clusters well,
and thus to allow testing of the CDM expectation on dark-matter halo density
profiles.
  METHODS. We develop an algorithm further that we had recently proposed for
this purpose. It recovers a lensing potential optimally reproducing
observations of both strong and weak-lensing effects by combining high
resolution in cluster cores with the larger-scale information from weak
lensing. The main extensions concern the accommodation of mild non-linearity in
inner iterations, the progressive increase in resolution in outer iterations,
and the introduction of a suitable regularisation term. The linearity of the
method is essentially preserved.
  RESULTS. We demonstrate the success of the algorithm with both idealised and
realistic simulated data, showing that the simulated lensing mass distribution
and its density profile are well reproduced. We then apply it to weak and
strong lensing data of the cluster MS 2137 and obtain a parameter-free solution
which is in good qualitative agreement with earlier parametric studies.


title: Curvature flows and CMC hypersurfaces

abstract:
  We give an overview of the existence and regularity results for curvature
flows and how these flows can be used to solve some problems in geometry and
physics.


title: DM particles: how warm they can be?

abstract:
  One of important questions concerning particles which compose the Dark Matter
(DM) is their average speed. We consider the model of relativistic weakly
interacting massive particles and try to impose an upper bound on their actual
and past warmness through the analysis of density perturbations and comparison
with the LSS data. It is assumed that the DM can be described by the recently
invented model of reduced relativistic gas (RRG). The equation of state of the
RRG model is closely reproducing the one of the Maxwell distribution, while
being much simpler. This advantage of the RRG model makes our analysis very
efficient. As a result we arrive at the rigid and model-independent bound for
the DM warmness without using the standard (much more sophisticated) approach
based on the Einstein-Boltzmann system of equations.


title:
Single transverse-spin asymmetry for $D$-meson production in
  semi-inclusive deep inelastic scattering

abstract:
  We study the single-transverse spin asymmetry for open charm production in
the semi-inclusive lepton-hadron deep inelastic scattering. We calculate the
asymmetry in terms of the QCD collinear factorization approach for $D$ mesons
at high enough $P_{h\perp}$, and find that the asymmetry is proportional to the
twist-three tri-gluon correlation function in the proton. With a simple model
for the tri-gluon correlation function, we estimate the asymmetry for both
COMPASS and eRHIC kinematics, and discuss the possibilities of extracting the
tri-gluon correlation function in these experiments.


title: Electroweak Baryogenesis with a Pseudo-Goldstone Higgs

abstract:
  We examine the nature of electroweak Baryogenesis when the Higgs boson's
properties are modified by the effects of new physics. We utilize the effective
potential to one loop (ring improving the finite temperature perturbative
expansion) while retaining parametrically enhanced dimension six operators of
O(v^2/f^2) in the Higgs sector. These parametrically enhanced operators would
be present if the Higgs is a pseudo-goldstone boson of a new physics sector
with a characteristic mass scale Lambda ~ TeV, a coupling constant (4 pi) > g >
1 and a strong decay constant scale f = Lambda/g. We find that generically the
effect of new physics of this form allows a sufficiently first order
electro-weak phase transition so that the produced Baryon number can avoid
washing out, and has enhanced effects due to new sources CP violation. We also
improve the description of the electroweak phase transition in perturbation
theory by determining the thermal mass eigenstate basis of the standard model
gauge boson fields. This improves the calculation of the finite temperature
effects through incorporating mixing in the determination of the vector boson
thermal masses of the standard model. These effects are essential to
determining the nature of the phase transition in the standard model and are of
interest in our Pseudo-Goldstone Baryogenesis scenario.


title: Universal computation by quantum walk

abstract:
  In some of the earliest work on quantum mechanical computers, Feynman showed
how to implement universal quantum computation by the dynamics of a
time-independent Hamiltonian. I show that this remains possible even if the
Hamiltonian is restricted to be a sparse matrix with all entries equal to 0 or
1, i.e., the adjacency matrix of a low-degree graph. Thus quantum walk can be
regarded as a universal computational primitive, with any desired quantum
computation encoded entirely in some underlying graph. The main idea of the
construction is to implement quantum gates by scattering processes.


title:
Peering through the stellar wind of IGR J19140+0951 with simultaneous
  INTEGRAL/RXTE observations

abstract:
  We have used the RXTE and INTEGRAL satellites simultaneously to observe the
High Mass X-ray binary IGR J19140+0951. The spectra obtained in the 3--80 keV
range have allowed us to perform a precise spectral analysis of the system
along its binary orbit. The spectral evolution confirms the supergiant nature
of the companion star and the neutron star nature of the compact object. Using
a simple stellar wind model to describe the evolution of the photoelectric
absorption, we were able to restrict the orbital inclination angle in the range
38--75 degrees. This analysis leads to a wind mass-loss rate from the companion
star of ~5x 10e-8 Msun/year, consistent with an OB I spectral type. We have
detected a soft excess in at least four observations, for the first time for
this source. Such soft excesses have been reported in several HMXBs in the
past. We discuss the possible origin of this excess, and suggest, based on its
spectral properties and occurrences around the superior conjunction, that it
may be explained as the reprocessing of the X-ray emission originating from the
neutron star by the surrounding ionised gas.


title: On the question of ergodicity for minimal group actions on the circle

abstract:
  This work is devoted to the study of minimal, smooth actions of finitely
generated groups on the circle. We provide a sufficient condition for such an
action to be ergodic (with respect to the Lebesgue measure), and we illustrate
this condition by studying two relevant examples. Under an analogous
hypothesis, we also deal with the problem of the zero Lebesgue measure for
exceptional minimal sets. This hypothesis leads to many other interesting
conclusions, mainly concerning the stationary and conformal measures. Moreover,
several questions are left open. The methods work as well for codimension-one
foliations, though the results for this case are not explicitly stated.


title: The moduli space of flat SU(2)-bundles over a nonorientable surface

abstract:
  We study the topology of the moduli space of flat SU(2)-bundles over a
nonorientable surface X. This moduli space may be identified with the space of
homomorphisms Hom(\pi_1(X),SU(2)) modulo conjugation by SU(2). In particular,
we compute the (rational) equivariant cohomology ring of Hom(\pi_1(X),SU(2))
and use this to compute the ordinary cohomology groups of the quotient
Hom(\pi_1(X),SU(2))/SU(2). A key property is that the conjugation action is
equivariantly formal.


title:
Projections of Singular Vectors of Verma Modules over Rank 2 Kac-Moody
  Lie Algebras

abstract:
  We prove an explicit formula for a projection of singular vectors in the
Verma module over a rank 2 Kac-Moody Lie algebra onto the universal enveloping
algebra of the Heisenberg Lie algebra and of $sl_{2}$ (Theorem 3). The formula
is derived from a more general but less explicit formula due to Feigin, Fuchs
and Malikov [Funct. Anal. Appl. 20 (1986), no. 2, 103-113]. In the simpler case
of $A_{1}^{1}$ the formula was obtained in [Fuchs D., Funct. Anal. Appl. 23
(1989), no. 2, 154-156].


title: Adjoint string breaking in the pseudoparticle approach

abstract:
  We apply the pseudoparticle approach to SU(2) Yang-Mills theory and perform a
detailed study of the potential between two static charges for various
representations. Whereas for charges in the fundamental representation we find
a linearly rising confining potential, we clearly observe string breaking, when
considering charges in the adjoint representation. We also demonstrate Casimir
scaling and compute gluelump masses for different spin and parity. Numerical
results are in qualitative agreement with lattice results.


title: Max Cut and the Smallest Eigenvalue

abstract:
  We describe a new approximation algorithm for Max Cut. Our algorithm runs in
$\tilde O(n^2)$ time, where $n$ is the number of vertices, and achieves an
approximation ratio of $.531$. On instances in which an optimal solution cuts a
$1-\epsilon$ fraction of edges, our algorithm finds a solution that cuts a
$1-4\sqrt{\epsilon} + 8\epsilon-o(1)$ fraction of edges.
  Our main result is a variant of spectral partitioning, which can be
implemented in nearly linear time. Given a graph in which the Max Cut optimum
is a $1-\epsilon$ fraction of edges, our spectral partitioning algorithm finds
a set $S$ of vertices and a bipartition $L,R=S-L$ of $S$ such that at least a
$1-O(\sqrt \epsilon)$ fraction of the edges incident on $S$ have one endpoint
in $L$ and one endpoint in $R$. (This can be seen as an analog of Cheeger's
inequality for the smallest eigenvalue of the adjacency matrix of a graph.)
Iterating this procedure yields the approximation results stated above.
  A different, more complicated, variant of spectral partitioning leads to an
$\tilde O(n^3)$ time algorithm that cuts $1/2 + e^{-\Omega(1/\eps)}$ fraction
of edges in graphs in which the optimum is $1/2 + \epsilon$.


title: Magnetism in small bimetallic Mn-Co clusters

abstract:
  Effects of alloying on the electronic and magnetic properties of
Mn$_{x}$Co$_{y}$ ($x+y$=$n$=2-5; $x$=0-$n$) and Mn$_2$Co$_{11}$ nanoalloy
clusters are investigated using the density functional theory (DFT). Unlike the
bulk alloy, the Co-rich clusters are found to be ferromagnetic and the magnetic
moment increases with Mn-concentration, and is larger than the moment of pure
Co$_n$ clusters of same size. For a particular sized cluster the magnetic
moment increases by 2 $\mu_B$/Mn-substitution, which is found to be independent
of the size and composition. All these results are in good agreement with
recent Stern-Gerlach (SG) experiments [Phys. Rev. B {\bf 75}, 014401 (2007) and
Phys. Rev. Lett. {\bf 98}, 113401 (2007)]. Likewise in bulk Mn$_x$Co$_{1-x}$
alloy, the local Co-moment decreases with increasing Mn-concentration.


title: Time-dependent CP Asymmetries in $B^0\to K^0_S\rho^0\gamma$ Decays

abstract:
  We report the first measurement of CP-violation parameters in B^0 ->
K_S^0\rho^0\gamma decays based on 657 million B\bar B pairs collected with the
Belle detector at the KEKB asymmetric-energy collider. We measure the
time-dependent CP violating parameter S_{K_S^0\rho^0\gamma}= 0.11 +/-
0.33(stat.)^{+0.05}_{-0.09}(syst.). We also obtain the effective direct CP
violating parameter A_eff=0.05 +/- 0.18(stat.) +/- 0.06(syst.) for
m_{K_S\pi^+\pi^-}<1.8 GeV/c^2 and 0.6 GeV/c^2<m_{\pi^+\pi^-}<0.9 GeV/c^2.


title: Simple SL(n)-Modules with Normal Closures of Maximal Torus Orbits

abstract:
  Let $T$ be the subgroup of diagonal matrices in the group SL(n). The aim of
this paper is to find all finite-dimensional simple rational SL(n)-modules $V$
with the following property: for each point $v\in V$ the closure $\bar{Tv}$ of
its $T$-orbit is a normal affine variety. Moreover, for any SL(n)-module
without this property a $T$-orbit with non-normal closure is constructed. The
proof is purely combinatorial: it deals with the set of weights of simple
SL(n)-modules. The saturation property is checked for each subset in the set of
weights.


title: Universal resonant ultracold molecular scattering

abstract:
  The elastic scattering amplitudes of indistinguishable, bosonic,
strongly-polar molecules possess universal properties at the coldest
temperatures due to wave propagation in the long-range dipole-dipole field.
Universal scattering cross sections and anisotropic threshold angular
distributions, independent of molecular species, result from careful tuning of
the dipole moment with an applied electric field. Three distinct families of
threshold resonances also occur for specific field strengths, and can be both
qualitatively and quantitatively predicted using elementary adiabatic and
semi-classical techniques. The temperatures and densities of heteronuclear
molecular gases required to observe these univeral characteristics are
predicted. PACS numbers: 34.50.Cx, 31.15.ap, 33.15.-e, 34.20.-b


title: Nonaxial-octupole effect in superheavy nuclei

abstract:
  The triaxial-octupole Y$_{32}$ correlation in atomic nuclei has long been
expected to exist but experimental evidence has not been clear. We find, in
order to explain the very low-lying 2$^-$ bands in the transfermium mass
region, that this exotic effect may manifest itself in superheavy elements.
Favorable conditions for producing triaxial-octupole correlations are shown to
be present in the deformed single-particle spectrum, which is further supported
by quantitative Reflection Asymmetric Shell Model calculations. It is predicted
that the strong nonaxial-octupole effect may persist up to the element 108. Our
result thus represents the first concrete example of spontaneous breaking of
both axial and reflection symmetries in the heaviest nuclear systems.


title: Classification of curves in 2D and 3D via affine integral signatures

abstract:
  We propose a robust classification algorithm for curves in 2D and 3D, under
the special and full groups of affine transformations. To each plane or spatial
curve we assign a plane signature curve. Curves, equivalent under an affine
transformation, have the same signature. The signatures introduced in this
paper are based on integral invariants, which behave much better on noisy
images than classically known differential invariants. The comparison with
other types of invariants is given in the introduction. Though the integral
invariants for planar curves were known before, the affine integral invariants
for spatial curves are proposed here for the first time. Using the inductive
variation of the moving frame method we compute affine invariants in terms of
Euclidean invariants. We present two types of signatures, the global signature
and the local signature. Both signatures are independent of parameterization
(curve sampling). The global signature depends on the choice of the initial
point and does not allow us to compare fragments of curves, and is therefore
sensitive to occlusions. The local signature, although is slightly more
sensitive to noise, is independent of the choice of the initial point and is
not sensitive to occlusions in an image. It helps establish local equivalence
of curves. The robustness of these invariants and signatures in their
application to the problem of classification of noisy spatial curves extracted
from a 3D object is analyzed.


title: Dissipative accretion flows around a rotating black hole

abstract:
  We study the dynamical structure of a cooling dominated rotating accretion
flow around a spinning black hole. We show that non-linear phenomena such as
shock waves can be studied in terms of only three flow parameters, namely, the
specific energy (${\cal E}$), the specific angular momentum ($\lambda$) and the
accretion rate (${\dot m}$) of the flow. We present all possible accretion
solutions. We find that a significant region of the parameter space in the
${\cal E}-\lambda$ plane allows global accretion shock solutions. The effective
area of the parameter space for which the Rankine-Hugoniot shocks are possible
is maximum when the flow is dissipation free. It decreases with the increase of
cooling effects and finally disappears when the cooling is high enough. We show
that shock forms further away when the black hole is rotating compared to the
solution around a Schwarzschild black hole with identical flow parameters at a
large distance. However, in a normalized sense, the flow parameters for which
the shocks form around the rotating black holes are produced shocks closer to
the hole. The location of the shock is also dictated by the cooling efficiency
in that higher the accretion rate (${\dot m}$), the closer is the shock
location. We believe that some of the high frequency quasi-periodic
oscillations may be due to the flows with higher accretion rate around the
rotating black holes.


title: Nodal Superconductivity with Multiple Gaps in SmFeAsO$_{0.9}$F$_{0.1}$

abstract:
  We report the observation of two gaps in the superconductor
SmFeAsO$_{0.9}$F$_{0.1}$ (F-SmFeAsO) with $T_c=51.5K$ as measured by
point-contact spectroscopy. Both gaps decrease with temperature and vanish at
$T_c$ and the temperature dependence of the gaps are described by the
theoretical prediction of the Bardeen-Cooper-Schrieffer (BCS) theory. A
zero-bias conductance peak (ZBCP) was observed, indicating the presence of
Andreev bound states at the surface of F-SmFeAsO. Our results strongly suggest
an unconventional nodal superconductivity with multiple gaps in F-SmFeAsO.


title: Renormalizable minimal SO(10) GUT in 4D and 5D

abstract:
  This report is a review of the present status of GUT, especially
renormalizable minimal SO(10) GUT, and its future prospect.
  It consists of two parts. In part I, I review how the minimal renormalizable
supersymmetric SO(10) GUT, an SO(10) framework with only one ${\bf 10}$ and one
$\bar{\bf 126}$ Higgs multiplets in the Yukawa sector, is attractive because of
its high predictivity. Indeed it not only gave a consistent predictions on
neutrino oscillation data but also did reasonable and interesting values for
Leptogenesis, LFV, muon g-2, neutrinoless double beta decay etc. However, this
model suffers from problems, apart from the small deviations from the observed
values, related to running of gauge couplings and proton decay. The gauge
coupling unification may be spoiled due to the presence of intermediate scales
much lighter than the grand unification (GUT) scale. In addition, the gauge
couplings blow up around the GUT scale because of the presence of Higgs
multiplets of large representations. In order to remedy these pathologies, in
part II, we extend GUT into 5D. We propose two approaches: one is to consider
the warped extra dimension, using the bulk Higgs profile to explain the
intermediate energy scales. Another is to use the orbifold GUT. Both approaches
are complementary to each other.


title:
Statistical Characterization of a 1D Random Potential Problem - with
  applications in score statistics of MS-based peptide sequencing

abstract:
  We provide a complete thermodynamic solution of a 1D hopping model in the
presence of a random potential by obtaining the density of states. Since the
partition function is related to the density of states by a Laplace transform,
the density of states determines completely the thermodynamic behavior of the
system. We have also shown that the transfer matrix technique, or the so-called
dynamic programming, used to obtain the density of states in the 1D hopping
model may be generalized to tackle a long-standing problem in statistical
significance assessment for one of the most important proteomic tasks - peptide
sequencing using tandem mass spectrometry data.


title:
Perturbative Photon Fluxes Generated by High-Frequency Gravitational
  Waves and Their Physical Effects

abstract:
  We consider the electromagnetic (EM) perturbative effects produced by the
high-frequency gravitational waves (HFGWs) in the GHz band in a special EM
resonance system, which consists of fractal membranes, a Gaussian beam (GB)
passing through a static magnetic field. It is predicted, under the
synchroresonance condition, coherence modulation of the HFGWs to the
preexisting transverse components of the GB produces the transverse
perturbative photon flux (PPF),which has three novel and important properties:
(1)The PPF has maximum at a longitudinal symmetrical surface of the GB where
the transverse background photon flux (BPF) vanishes; (2) the resonant effect
will be high sensitive to the propagating directions of the HFGWs; (3) the PPF
reflected or transmitted by the fractal membrane exhibits a very small decay
compared with very large decay of the much stronger BPF. Such properties might
provide a new way to distinguish and display the perturbative effects produced
by the HFGWs. We also discuss the high-frequency asymptotic behavior of the
relic GWs in the microwave band and the positive definite issues of their
energy-momentum pseudo-tensor.


title: Coulomb Branch of the Lorentzian Three Algebra Theory

abstract:
  We analyze the coulomb branch of the non-unitary Lorentzian three algebra
theory that has been proposed as a possible candidate for describing the world
volume theory of multiple M2-branes. In order that it describes the theory of
multiple M2-branes in flat eleven dimensional space-time, the ghost fields must
decouple and the physical theory must be independent of the eight coordinates
of the moduli space representing the center of mass coordinates of the branes.
We show that the structure of the Coulomb branch is consistent with this
requirement. While the full moduli space has the structure of a Lorentzian
space modded out by a Lorentz transformation, the physical subspace has the
correct structure of the moduli space of multiple M2-branes. We also suggest a
systematic procedure for testing the consistency of the theory by computing the
higher derivative corrections to the effective action obtained by integrating
out the massive modes propagating in the loop.


title: Roton softening and supersolidity in Rb spinor condensates

abstract:
  Superfluids with a tendency towards periodic crystalline order have both a
phonon and roton like spectrum of collective modes. The softening of the roton
spectrum provides one route to a supersolid. We show that roton softening
occurs in 87Rb spinor condensates once dipolar interactions and spin dynamics
are taken into account. By including the effects of a quasi-two-dimensional
geometry and rapid Larmor precession, we show a dynamical instability develops
in the collective mode spectrum at finite wavevectors. We construct phase
diagrams showing a variety of instabilities as a function of the direction of
the magnetic field and strength of the quadratic Zeeman shift. Our results
provide a possible explanation of current experiments in the Berkeley group
Phys. Rev. Lett. 100:170403 (2008).


title: Surface-sensitive NMR in optically pumped semiconductors

abstract:
  We present a scheme of surface-sensitive nuclear magnetic resonance in
optically pumped semiconductors, where an NMR signal from a part of the surface
of a bulk compound semiconductor is detected apart from the bulk signal. It
utilizes optically oriented nuclei with a long spin-lattice relaxation time as
a polarization reservoir for the second (target) nuclei to be detected. It
provides a basis for the nuclear spin polarizer [IEEE Trans. Appl. Supercond.
14, 1635 (2004)], which is a polarization reservoir at a surface of the
optically pumped semiconductor that polarizes nuclear spins in a target
material in contact through the nanostructured interfaces.


title: Words Maps and Spectra of Random Graph Lifts

abstract:
  We begin with a new analysis of formal words. Let w be a formal word in
letters g_1,...,g_k. The word map associated with w maps the permutations
s_1,...,s_k in S_n to the permutation obtained by replacing for each i, every
occurrence of g_i in w by s_i. We investigate the random variable X_w^n that
counts the fixed points in this permutation when the s_i are selected uniformly
at random. A major ingredient of our work is a new categorization of words
which considerably extends the dichotomy of primitive vs. imprimitive words. We
establish some results and make a few conjectures about the relation between
the expectation E(X_w^n) and this new categorization.
  This analysis contributes deeply to our study of the spectra of random lifts
of graphs. Let G be a connected graph, and let the infinite tree T be its
universal cover space. If L and R are the spectral radii of G and T
respectively, then, as shown by J. Friedman, for almost every n-lift H of G,
all "new" eigenvalues of H are < O(L^(1/2)R^(1/2)). We improve this upper bound
to O(L^(1/3)R^(2/3)), and our aforementioned conjectures suggest a possible
approach to proving an upper bound of O(R). This is a generalization of the
problem of bounding the second eigenvalue in a random 2d-regular graph.
  As an aside, we obtain a new conceptual and relatively simple proof of a
theorem of A. Nica, which determines, for every fixed w, the limit distribution
(as n \to \infty) of X_w^n. A surprising aspect of this theorem is that the
answer depends only on the largest integer d so that w=u^d for some word u.


title:
Electric-field switching of exciton spin splitting in coupled quantum
  dots

abstract:
  We investigate theoretically the spin splitting of the exciton states in
semiconductor coupled quantum dots (CQDs) containing a single magnetic ion. We
find that the spin splitting can be switched on/off in the CQDs \textit{via}
the \textit{sp-d}exchange interaction using the electric field. An interesting
bright-to-dark exciton transition can be found and significantly affects the
photoluminescence spectrum. This phenonmenon is induced by the transition of
the ground exciton state, arising from the hole mixing effect, between the
bonding and antibonding states.


title:
Multiple time scales in cataclysmic binaries. The low-field magnetic
  dwarf nova DO Draconis

abstract:
  We study the variability of the cataclysmic variable DO Dra, on time-scales
of between minutes and decades.
  The characteristic decay time dt/dm=0.902(3) days/mag was estimated from our
3 nights of CCD R observations. The quiescent data show a photometric wave with
a cycle about 303(15)d. We analyzed the profile of the composite (or mean)
outburst. We discovered however, that a variety of different outburst heights
and durations had occurred, contrary to theoretical predictions. With
increasing maximum brightness, we find that the decay time also increases; this
is in contrast to the model predictions, which indicate that outbursts should
have a constant shape. This is interpreted as representing the presence of
outburst-to-outburst variability of the magnetospheric radius. A presence of a
number of missed weak narrow outbursts is predicted from this statistical
relationship. A new type of variability is detected, during 3 subsequent nights
in 2007: periodic (during one nightly run) oscillations with rapidly-decreasing
frequency from 86 to 47 cycles/day and a semi-amplitude increasing from 0.06 to
0. 10, during a monotonic brightness increase from 14. 27 to 14. 13. This
phenomenon was observed only during an unusually prolonged event of about 1 mag
brightening in 2007 (lasting till autumn), during which no (expected) outburst
was detected. We refer to this behaviour as to the transient periodic
oscillations (TPO). To study this new and interesting phenomenon, new regular
photometric and spectral (in a target of opportunity mode) observations are
required.


title: On explicit free field realizations of current algebras

abstract:
  We construct the explicit free field representations of the current algebras
$so(2n)_k$, $so(2n+1)_k$ and $sp(2n)_k$ for a generic positive integer $n$ and
an arbitrary level $k$. The corresponding energy-momentum tensors and screening
currents of the first kind are also given in terms of free fields.


title: Chiral Properties of Baryon Fields with Flavor SU(3) Symmetry

abstract:
  We investigate chiral properties of local (non-derivative) fields of baryons
consisting of three quarks with flavor SU(3) symmetry. We construct explicitly
independent local three-quark fields belonging to definite Lorentz and flavor
representations. Chiral symmetry is spontaneously broken and therefore the
baryon fields can have different chiral representations. It turns out that the
allowed chiral representations are strongly correlated with the Lorentz group
representations due to the color and spatial structure of the local three-quark
fields. We discuss some implications of the allowed chiral symmetry
representations on phenomenological Lagrangians with chiral U(3)_L \otimes
U(3)_R symmetry.


title: The I^G J^{PC}=1^- 1^{-+} Tetraquark States

abstract:
  We study the tetraquark states with I^G J^{PC}=1^- 1^{-+} in the QCD sum
rule. After exhausting all possible flavor structures, we analyses both the SVZ
and finite energy sum rules. Both approaches lead to a mass around 1.6 GeV for
the state with the quark contents q q q_bar q_bar, and around 2.0 GeV for the
state with the quark contents q s q_bar s_bar. The flavor structure 3_bar *
6_bar + 6 * 3 is preferred. Our analysis strongly indicates that both pi1(1600)
and pi1(2015) are also compatible with the exotic tetraquark interpretation,
which are sometimes labeled as candidates of the 1^{-+} hybrid mesons. Moreover
one of their dominant decay modes is a pair of axial-vector and pseudoscalar
mesons such as b1(1235) pi, which is sometimes considered as the characteristic
decay mode of the hybrid mesons.


title: On the minima and convexity of Epstein Zeta function

abstract:
  Let $Z_n(s; a_1,..., a_n)$ be the Epstein zeta function defined as the
meromorphic continuation of the function
  \sum_{k\in\Z^n\setminus\{0\}}(\sum_{i=1}^n [a_i k_i]^2)^{-s},
  \text{Re} s>\frac{n}{2}
  to the complex plane. We show that for fixed $s\neq n/2$, the function
$Z_n(s; a_1,..., a_n)$, as a function of $(a_1,..., a_n)\in (\R^+)^n$ with
fixed $\prod_{i=1}^n a_i$, has a unique minimum at the point $a_1=...=a_n$.
When $\sum_{i=1}^n c_i$ is fixed, the function $$(c_1,..., c_n)\mapsto Z_n(s;
e^{c_1},..., e^{c_n})$$ can be shown to be a convex function of any $(n-1)$ of
the variables $\{c_1,...,c_n\}$. These results are then applied to the study of
the sign of $Z_n(s; a_1,..., a_n)$ when $s$ is in the critical range $(0,
n/2)$. It is shown that when $1\leq n\leq 9$, $Z_n(s; a_1,..., a_n)$ as a
function of $(a_1,..., a_n)\in (\R^+)^n$, can be both positive and negative for
every $s\in (0,n/2)$. When $n\geq 10$, there are some open subsets $I_{n,+}$ of
$s\in(0,n/2)$, where $Z_{n}(s; a_1,..., a_n)$ is positive for all $(a_1,...,
a_n)\in(\R^+)^n$. By regarding $Z_n(s; a_1,..., a_n)$ as a function of $s$, we
find that when $n\geq 10$, the generalized Riemann hypothesis is false for all
$(a_1,...,a_n)$.


title:
Security proof of differential phase shift quantum key distribution in
  the noiseless case

abstract:
  Differential phase shift quantum key distribution systems have a high
potential for achieving high speed key generation. However, its unconditional
security proof is still missing, even though it has been proposed for many
years. Here, we prove its security against collective attacks with a weak
coherent light source in the noiseless case (i.e. no bit error). The only
assumptions are that quantum theory is correct, the devices are perfect and
trusted and the key size is infinite. Our proof works on threshold detectors.
We compute the lower bound of the secret key generation rate using the
information-theoretical security proof method. Our final result shows that the
lower bound of the secret key generation rate per pulse is linearly
proportional to the channel transmission probability if Bob's detection counts
obey the binomial distribution.


title:
"GiGa": the Billion Galaxy HI Survey -- Tracing Galaxy Assembly from
  Reionization to the Present

abstract:
  In this paper, we review the Billion Galaxy Survey that will be carried out
at radio--optical wavelengths to micro--nanoJansky levels with the telescopes
of the next decades. These are the Low-Frequency Array, the Square Kilometer
Array and the Large Synoptic Survey Telescope as survey telescopes, and the
Thirty Meter class Telescopes for high spectral resolution+AO, and the James
Webb Space Telescope (JWST) for high spatial resolution near--mid IR follow-up.
With these facilities, we will be addressing fundamental questions like how
galaxies assemble with super-massive black-holes inside from the epoch of First
Light until the present, how these objects started and finished the
reionization of the universe, and how the processes of star-formation, stellar
evolution, and metal enrichment of the IGM proceeded over cosmic time. We also
summarize the high-resolution science that has been done thus far on high
redshift galaxies with the Hubble Space Telescope (HST). Faint galaxies have
steadily decreasing sizes at fainter fluxes and higher redshifts, reflecting
the hierarchical formation of galaxies over cosmic time. HST has imaged this
process in great structural detail to z<~6. We show that ultradeep
radio-optical surveys may slowly approach the natural confusion limit, where
objects start to unavoidably overlap because of their own sizes, which only SKA
can remedy with HI redshifts for individual sub-clumps. Finally, we summarize
how the 6.5 meter James Webb Space Telescope (JWST) will measure first light,
reionization, and galaxy assembly in the near--mid-IR.


title:
Differential rotation in giant planets maintained by density-stratified
  turbulent convection

abstract:
  The zonal winds on the surfaces of giant planets vary with latitude. Jupiter
and Saturn, for example, have several bands of alternating eastward (prograde)
and westward (retrograde) jets relative to the angular velocity of their global
magnetic fields. These surface wind profiles are likely manifestations of the
variations in depth and latitude of angular velocity deep within the liquid
interiors of these planets. Two decades ago it was proposed that this
differential rotation could be maintained by vortex stretching of convective
fluid columns that span the interiors of these planets from the northern
hemisphere surface to the southern hemisphere surface. This now classic
mechanism explains the differential rotation seen in laboratory experiments and
in computer simulations of, at best, weakly turbulent convection in rotating
constant-density fluid spheres. However, these experiments and simulations are
poor approximations for the density-stratified strongly-turbulent interiors of
giant planets. The long thin global convective columns predicted by the classic
geostrophic theory for these planets would likely not develop. Here we propose
a much more robust mechanism for maintaining differential rotation in radius
based on the local generation of vorticity as rising plumes expand and sinking
plumes contract. Our high-resolution two-dimensional computer simulations
demonstrate how this mechanism could maintain either prograde or retrograde
surface winds in the equatorial region of a giant planet depending on how the
density scale height varies with depth.


title: Worldsheet theories for non-geometric string backgrounds

abstract:
  We show that twisted doubled tori can be used to construct a general class of
worldsheet models describing non-geometric string backgrounds. By employing a
first order formulation of interacting chiral bosons, we first refine the
analysis on the general conditions of worldsheet Lorentz invariance and then
prove that twisted doubled tori provide good duality symmetric backgrounds.
Subsequently we apply our general analysis to several examples which enable us
to gain new insight on the difference between geometric, locally geometric and
genuine non-geometric backgrounds.


title:
Identification of microscopic spin-polarization coupling in the
  ferroelectric phase of a magnetoelectric multiferroic CuFe1-xAlxO2

abstract:
  We have performed synchrotron radiation X-ray and neutron diffraction
measurements on magnetoelectric multiferroic CuFe1-xAlxO2 (x=0.0155), which has
a proper helical magnetic structure with incommensurate propagation wave vector
in the ferroelectric phase. The present measurements revealed that the
ferroelectric phase is accompanied by lattice modulation with a wave number 2q,
where q is the magnetic modulation wave number. We have calculated the Fourier
spectrum of the spatial modulations in the local electric polarization using a
microscopic model proposed by Arima [T. Arima, J. Phys. Soc. Jpn. 76, 073702
(2007)]. Comparing the experimental results with the calculation results, we
found that the origin of the 2q-lattice modulation is not conventional
magnetostriction but the variation in the metal-ligand hybridization between
the magnetic Fe^3+ ions and ligand O^2- ions. Combining the present results
with the results of a previous polarized neutron diffraction study [Nakajima et
al., Phys. Rev. B 77 052401 (2008)], we conclude that the microscopic origin of
the ferroelectricity in CuFe1-xAlxO2 is the variation in the metal-ligand
hybridization with spin-orbit coupling.


title:
SAPHIR - a multi-scale, multi-resolution modeling environment targeting
  blood pressure regulation and fluid homeostasis

abstract:
  We present progress on a comprehensive, modular, interactive modeling
environment centered on overall regulation of blood pressure and body fluid
homeostasis. We call the project SAPHIR, for "a Systems Approach for
PHysiological Integration of Renal, cardiac, and respiratory functions". The
project uses state-of-the-art multi-scale simulation methods. The basic core
model will give succinct input-output (reduced-dimension) descriptions of all
relevant organ systems and regulatory processes, and it will be modular,
multi-resolution, and extensible, in the sense that detailed submodules of any
process(es) can be "plugged-in" to the basic model in order to explore, eg.
system-level implications of local perturbations. The goal is to keep the basic
core model compact enough to insure fast execution time (in view of eventual
use in the clinic) and yet to allow elaborate detailed modules of target
tissues or organs in order to focus on the problem area while maintaining the
system-level regulatory compensations.


title: Fusion de classifieurs pour la classification d'images sonar

abstract:
  In this paper, we present some high level information fusion approaches for
numeric and symbolic data. We study the interest of such method particularly
for classifier fusion. A comparative study is made in a context of sea bed
characterization from sonar images. The classi- fication of kind of sediment is
a difficult problem because of the data complexity. We compare high level
information fusion and give the obtained performance.


title:
Experts Fusion and Multilayer Perceptron Based on Belief Learning for
  Sonar Image Classification

abstract:
  The sonar images provide a rapid view of the seabed in order to characterize
it. However, in such as uncertain environment, real seabed is unknown and the
only information we can obtain, is the interpretation of different human
experts, sometimes in conflict. In this paper, we propose to manage this
conflict in order to provide a robust reality for the learning step of
classification algorithms. The classification is conducted by a multilayer
perceptron, taking into account the uncertainty of the reality in the learning
stage. The results of this seabed characterization are presented on real sonar
images.


title:
Generalized proportional conflict redistribution rule applied to Sonar
  imagery and Radar targets classification

abstract:
  In this chapter, we present two applications in information fusion in order
to evaluate the generalized proportional conflict redistribution rule presented
in the chapter \cite{Martin06a}. Most of the time the combination rules are
evaluated only on simple examples. We study here different combination rules
and compare them in terms of decision on real data. Indeed, in real
applications, we need a reliable decision and it is the final results that
matter. Two applications are presented here: a fusion of human experts opinions
on the kind of underwater sediments depict on sonar image and a classifier
fusion for radar targets recognition.


title: Unparticle Realization Through Continuous Mass Scale Invariant Theories

abstract:
  We consider scale invariant theories of continuous mass fields, and show how
interactions of these fields with the standard model can reproduce unparticle
interactions. There is no fixed point or dimensional transmutation involved in
this approach. We generalize interactions of the standard model to multiple
unparticles in this formalism and explicitly work out some examples, in
particular we show that the product of two scalar unparticles behaves as a
normalized scalar unparticle with dimension equal to the sum of the two
composite unparticle dimensions. Extending the formalism to scale invariant
interactions of continuous mass fields, we calculate three point function of
unparticles.


title:
Optical and gamma-ray emissions from internal forward-reverse shocks:
  application to GRB 080319B?

abstract:
  In the popular internal shock model for the prompt emission of gamma-ray
bursts (GRBs), collisions between a series of relativistic shells generate lots
of paired forward and reverse shocks. We show that the synchrotron emission
produced by the forward and reverse shocks respectively could peak at two quite
different energy bands if the Lorentz factors of these two types of shocks are
significantly different with each other (e.g., one shock is relativistic and
the other is Newtonian). We then investigate whether this scenario is
applicable to the case of GRB 080319B and find that a bimodal distribution of
the shell Lorentz factors, peaking at $\sim400$ and $\sim10^5$, is required. In
addition, this scenario predicts an accompanying inverse-Compton (IC) GeV
emission with a luminosity comparable to (not much higher than) that of the
synchrotron MeV emission, which can be tested with future \textit{Fermi}
observations.


title: Examples of limits of Frobenius (type) structures: the singularity case

abstract:
  We give examples of families of Frobenius type structures on the punctured
plane and we study their limits at the boundary. We then discuss the existence
of a limit Frobenius manifold. We also give an example of a logarithmic
Frobenius manifold.


title: Uniformly frustrated bosonic Josephson-junction arrays

abstract:
  We derive a uniformly frustrated $XY$ model that describes two-dimensional
Josephson-junction arrays consisting of rotating Bose-Einstein condensates
trapped by both a harmonic trap and a corotating deep optical lattice. The
harmonic trap makes the coupling constant of the model have a nonuniform
parabolic dependance. We study the ground state through Monte Carlo simulations
in a wide range of the frustration parameter $f$, revealing a rich variety of
vortex patterns.


title: Some Studies in Noncommutative Quantum Field Theories

abstract:
  The central theme of this thesis is to study some aspects of noncommutative
quantum mechanics and noncommutative quantum field theory. We explore how
noncommutative structures can emerge and study the consequences of such
structures in various physical models.


title:
Zeta functions, heat kernels and spectral asymptotics on degenerating
  families of discrete tori

abstract:
  By a discrete torus we mean the Cayley graph associated to a finite product
of finite cycle groups with generating set given by choosing a generator for
each cyclic factor. In this article we study the spectral theory of the
combinatorial Laplacian for sequences of discrete tori when the orders of the
cyclic factors tend to infinity at comparable rates. First we show that the
sequence of heat kernels corresponding to the degenerating family converges,
after re-scaling, to the heat kernel on an associated real torus. We then
establish an asymptotic expansion, in the degeneration parameter, of the
determinant of the combinatorial Laplacian. The zeta-regularized determinant of
the Laplacian of the limiting real torus appears as the constant term in this
expansion. On the other hand, using a classical theorem by Kirchhoff the
determinant of the combinatorial Laplacian of a finite graph divided by the
number of vertices equals the number of spanning trees, called the complexity,
of the graph. As a result, we establish a precise connection between the
complexity of the Cayley graphs of finite abelian groups and heights of real
tori. It is also known that spectral determinants on discrete tori can be
expressed using trigonometric functions and that spectral determinants on real
tori can be expressed using modular forms on general linear groups. Another
interpretation of our analysis is thus to establish a link between limiting
values of certain products of trigonometric functions and modular forms. The
heat kernel analysis which we employ uses a careful study of I-Bessel
functions. Our methods extend to prove the asymptotic behavior of other
spectral invariants through degeneration, such as special values of spectral
zeta functions and Epstein-Hurwitz type zeta functions.


title:
Hawking radiation as tunneling derived from Black Hole Thermodynamics
  through the quantum horizon

abstract:
  We show that the first law of the black hole thermodynamics can lead to the
tunneling probability through the quantum horizon by calculating the change of
entropy with the quantum gravity correction and the change of surface gravity
is presented clearly in the calculation. The method is also applicable to the
general situation which is independent on the form of black hole entropy and
this verifies the connection of black hole tunneling with thermodynamics
further. In the end we discuss the crucial role of the relation between the
radiation temperature and surface gravity in this derivation.


title: Present status of the KADoNiS database

abstract:
  The "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars" (KADoNiS)
project is an online database for experimental cross sections relevant to the
$s$ process and $p$ process. It is available under
\http://nuclear-astrophysics.fzk.de/kadonis and consists of two parts. Part 1
is an updated sequel to the well-known Bao et al. compilations from 1987 and
2000, which is online since April 2005. An extension of this $s$-process
database to $(n,p)$ and $(n,\alpha)$ cross sections at $kT$= 30 keV, as in the
first version of the Bao compilation, is planned. The second part of KADoNiS is
a $p$-process library, which includes all available experimental data from
$(p,\gamma)$, $(p,n)$, $(\alpha,\gamma)$, $(\alpha,n)$, $(\alpha,\alpha)$,
$(n,\alpha)$ and $(\gamma,n)$ reactions in or close to the respective Gamow
window. Despite the great number of reactions required for a $p$-process
reaction network, experimental data is still scarce and up to now restricted to
stable targets. Given here is a short overview about the present status of the
KADoNiS database.


title:
Entanglement in a class of multiqubit mixed states without multipartite
  tangles

abstract:
  Based on quantum complementary relations (QCRs) and a purification scenario,
we analyze a class of N-qubit mixed states that are entangled but do not have
two-, and genuine three-, four-, ..., N-qubit entanglements. It is shown that
entanglement (one-tangle or negativity) in these mixed states is closely
related to the QCR entanglement of their purified states. In particular, it is
elaborated that when the mixed state does not have multipartite tangles (two-
and higher tangles), its entanglement is actually a kind of genuine
multipartite QCR entanglement between the system and its environment.


title:
Neutrino mass effects on vector and tensor CMB anisotropies in the
  presence of a primordial magnetic field

abstract:
  If a primordial magnetic field (PMF) is present during photon decoupling and
afterward, a finite neutrino mass can affect all modes of the CMB. In this
work, we expand on earlier studies of the scalar mode effects by constructing
the vector and tensor mode equations in the presence of massive neutrinos and a
PMF. We compute the power spectrum of the various modes in an illustrative
example and find that the neutrino mass can significantly affect the vector and
tensor modes when a PMF exists, while the effects are negligible for no PMF.
The most prominent result of the present analysis is the behavior of the EE
component of the tensor mode at low multipoles. For massive neutrinos the EE
mode can become comparable to the observed primary anisotropy. Therefore, if
and when the EE mode power spectrum is measured at low multipoles the
possibility exists to place a strong constraint on the sum of the neutrino
masses.


title: Discrete PT-symmetric models of scattering

abstract:
  One-dimensional scattering mediated by non-Hermitian Hamiltonians is studied.
A schematic set of models is used which simulate two point interactions at a
variable strength and distance. The feasibility of the exact construction of
the amplitudes is achieved via the discretization of the coordinate. By direct
construction it is shown that in all our models the probability is conserved.
This feature is tentatively attributed to the space- and time-reflection
symmetry (a.k.a. PT-symmetry) of our specific Hamiltonians.


title:
Extensions of the auxiliary field method to solve Schr\"{o}dinger
  equations

abstract:
  It has recently been shown that the auxiliary field method is an interesting
tool to compute approximate analytical solutions of the Schr\"{o}dinger
equation. This technique can generate the spectrum associated with an arbitrary
potential $V(r)$ starting from the analytically known spectrum of a particular
potential $P(r)$. In the present work, general important properties of the
auxiliary field method are proved, such as scaling laws and independence of the
results on the choice of $P(r)$. The method is extended in order to find
accurate analytical energy formulae for radial potentials of the form $a
P(r)+V(r)$, and several explicit examples are studied. Connections existing
between the perturbation theory and the auxiliary field method are also
discussed.


title:
$\mu$SR studies of the frustrated quasi-2d square-lattice spin system
  Cu(Cl,Br)La(Nb,Ta)$_{2}$O$_{7}$: evolution from spin-gap to antiferromagnetic
  state

abstract:
  We report muon spin relaxation ($\mu$SR) and magnetic susceptibility
measurements on Cu(Cl,Br)La(Nb,Ta)$_{2}$O$_{7}$, which demonstrate: (a) the
absence of static magnetism in (CuCl)LaNb$_{2}$O$_{7}$ down to 15 mK confirming
a spin-gapped ground state; (b) phase separation between partial volumes with a
spin-gap and static magnetism in (CuCl)La(Nb,Ta)$_{2}$O$_{7}$; (c)
history-dependent magnetization in the (Nb,Ta) and (Cl,Br) substitution
systems; (d) a uniform long-range collinear antiferromagnetic state in
(CuBr)LaNb$_{2}$O$_{7}$; and (e) a decrease of N\'eel temperature with
decreasing Br concentration $x$ in Cu(Cl$_{1-x}$Br$_{x}$)LaNb$_{2}$O$_{7}$ with
no change in the ordered Cu moment size for $0.33 \leq x \leq 1$. Together with
several other $\mu$SR studies of quantum phase transitions in
geometrically-frustrated spin systems, the present results reveal that the
evolution from a spin-gap to a magnetically ordered state is often associated
with phase separation and/or a first order phase transition.


title:
Perfectly matched layers for the stationary Schrodinger equation in a
  periodic structure

abstract:
  We construct a perfectly matched absorbing layer for stationary Schrodinger
equation with analytic slowly decaying potential in a periodic structure. We
prove the unique solvability of the problem with perfectly matched layer of
finite length and show that solution to this problem approximates a solution to
the original problem with an error that exponentially tends to zero as the
length of perfectly matched layer tends to infinity.


title: Shadows and intersections: stability and new proofs

abstract:
  We give a short new proof of a version of the Kruskal-Katona theorem due to
Lov\'asz. Our method can be extended to a stability result, describing the
approximate structure of configurations that are close to being extremal, which
answers a question of Mubayi. This in turn leads to another combinatorial proof
of a stability theorem for intersecting families, which was originally obtained
by Friedgut using spectral techniques and then sharpened by Keevash and Mubayi
by means of a purely combinatorial result of Frankl. We also give an algebraic
perspective on these problems, giving yet another proof of intersection
stability that relies on expansion of a certain Cayley graph of the symmetric
group, and an algebraic generalisation of Lov\'asz's theorem that answers a
question of Frankl and Tokushige.


title: Eclipse mapping of RW Tri in the low luminosity state

abstract:
  We analyzed the eclipse light curve of the nova-like star RW Tri in its low
luminosity state. During approximately 150 days, RW Tri was about one magnitude
fainter than in its usual state. Our eclipse map shows that the brightness
temperature in the disc ranges from 19000 K near the white dwarf to 8700 at the
disc edge. For the inner parts of accretion disc, the radial temperature
distribution is flatter than that predicted from the steady state models, and
for the outer parts, it is close to the R^(-3/4) law. Fitting of the
temperature distribution with one for the steady state disc model gives a mean
accretion rate of (3.85+-0.19) 10^{-9} M year^(-1). The hotspot in the disc is
placed at a distance of 0.17a from the white dwarf, where a is the orbital
separation.


title:
Calculating the Mordell-Weil rank of elliptic threefolds and the
  cohomology of singular hypersurfaces

abstract:
  In this paper we give a method for calculating the rank of a general elliptic
curve over the field of rational functions in two variables. We reduce this
problem to calculating the cohomology of a singular hypersurface in a weighted
projective 4-space. We then give a method for calculating the cohomology of a
certain class of singular hypersurfaces, extending work of Dimca for the
isolated singularity case.


title:
Precise Wavefront Correction with an Unbalanced Nulling Interferometer
  for Exo-Planet Imaging Coronagraphs

abstract:
  Very high dynamical range coronagraphs targeting direct exo-planet detection
(10^9 - 10^10 contrast) at small angular separation (few lambda/D units)
usually require an input wavefront quality on the order of ten thousandths of
wavelength RMS. We propose a novel method based on a pre-optics setup that
behaves partly as a low-efficiency coronagraph, and partly as a
high-sensitivity wavefront aberration compensator (phase and amplitude). The
combination of the two effects results in a highly accurate corrected
wavefront. First, an (intensity-) unbalanced nulling interferometer (UNI)
performs a rejection of part of the wavefront electric field. Then the
recombined output wavefront has its input aberrations magnified. Because of the
unbalanced recombination scheme, aberrations can be free of phase singular
points (zeros) and can therefore be compensated by a downstream phase and
amplitude correction (PAC) adaptive optics system, using two deformable
mirrors. In the image plane, the central star's peak intensity and the noise
level of its speckled halo are reduced by the UNI-PAC combination: the
output-corrected wavefront aberrations can be interpreted as an improved
compensation of the initial (eventually already corrected) incident wavefront
aberrations. The important conclusion is that not all the elements in the
optical setup using UNI-PAC need to reach the lambda/10000 rms surface error
quality.


title: Triangle packings and 1-factors in oriented graphs

abstract:
  An oriented graph is a directed graph which can be obtained from a simple
undirected graph by orienting its edges. In this paper we show that any
oriented graph G on n vertices with minimum indegree and outdegree at least
(1/2-o(1))n contains a packing of cyclic triangles covering all but at most 3
vertices. This almost answers a question of Cuckler and Yuster and is best
possible, since for n = 3 mod 18 there is a tournament with no perfect triangle
packing and with all indegrees and outdegrees (n-1)/2 or (n-1)/2 \pm 1. Under
the same hypotheses, we also show that one can embed any prescribed almost
1-factor, i.e. for any sequence n_1,...,n_t with n_1+...+n_t < n-O(1) we can
find a vertex-disjoint collection of directed cycles with lengths n_1,...,n_t.
In addition, under quite general conditions on the n_i we can remove the O(1)
additive error and find a prescribed 1-factor.


title:
Direct imaging of the structural change generated by dielectric
  breakdown in MgO based magnetic tunnel junctions

abstract:
  MgO based magnetic tunnel junctions are prepared to investigate the
dielectric breakdown of the tunnel barrier. The breakdown is directly
visualized by transmission electron microscopy measurements. The broken tunnel
junctions are prepared for the microscopy measurements by focussed ion beam out
of the junctions characterized by transport investigations. Consequently, a
direct comparison of transport behavior and structure of the intact and broken
junctions is obtained. Compared to earlier findings in Alumina based junctions,
the MgO barrier shows much more microscopic pinholes after breakdown. This can
be explained within a simple model assuming a relationship between the current
density at the breakdown and the rate of pinhole formation.


title:
An insight into spin-chain magnetism through Moessbauer spectroscopic
  investigations in Eu-doped Ca3Co2O6 and Ca3CoRhO6

abstract:
  We report the results of 151Eu Moessbauer effect and magnetization
measurements in the Eu-doped Ca3Co2O6 and Ca3CoRhO6, which are of great current
interest in the fields of spin-chain magnetism and geometrical frustration. We
find that there is a pronounced increase in the line-width of the Moessbauer
spectra below a certain characteristic temperature which is well-above the one
at which three-diensional ordering features set in. This unusual broadening of
the spectra indicates the existence of a characteristic temperature in these
'exotic' magnetic systems, attributable to the onset of incipient
one-dimensional magnetic order. This is inferred from an intriguing correlation
of this characteristic temperature with the paramagnetic Curie temperature (a
measure of intrachain coupling strength in these cases).


title: Magnetic behavior of nanocrystalline LaMn2Ge2

abstract:
  The compound, LaMn2Ge2, crystallizing in ThCr2Si2-type tetragonal crystal
structure, has been known to undergo ferromagnetic order below (T_C=) 326 K. In
this article, we report the magnetic behavior of nanocrystalline form of this
compound, obtained by high-energy ball-milling. T_C of this compound is reduced
maginally for the nanoform, whereas there is a significant reduction of the
magnitude of the saturation magnetic moment with increasing milling time. The
coercive field however increases with decreasing particle size. Thus, this work
provides a route to tune these parameters by reducing the particle size in this
ternary family.


title:
Atomistic Simulations of Elastic and Plastic Properties in Amorphous
  Silicon

abstract:
  We present here potential dependent mechanical properties of amorphous
silicon studied through molecular dynamics (MD) at low temperature. On average,
the localization of elementary plastic events and the co-ordination
defect-sites appears to be correlated. For Tersoff potential and SW potential
the plastic events centered on defects-sites prefer 5-fold defect sites, while
for modified Stillinger-Weber potential such plastic events choose 3-fold
defect sites. We also analyze the non-affine displacement field in amorphous
silicon obtained for different shear regime. The non-affine displacement field
localizes when plastic events occur and shows elementary shear band formation
at higher shear strains.


title: Emergent Gravity and Noncommutative Branes from Yang-Mills Matrix Models

abstract:
  The framework of emergent gravity arising from Yang-Mills matrix models is
developed further, for general noncommutative branes embedded in R^D. The
effective metric on the brane turns out to have a universal form reminiscent of
the open string metric, depending on the dynamical Poisson structure and the
embedding metric in R^D. A covariant form of the tree-level equations of motion
is derived, and the Newtonian limit is discussed. This points to the necessity
of branes in higher dimensions. The quantization is discussed qualitatively,
which singles out the IKKT model as a prime candidate for a quantum theory of
gravity coupled to matter. The Planck scale is then identified with the scale
of N=4 SUSY breaking. A mechanism for avoiding the cosmological constant
problem is exhibited.


title:
Unique mixing of the shift on the C*--algebras generated by the
  q--canonical commutation relations

abstract:
  The shift on the C^*--algebras generated by the Fock representation of the
q--commutation relations has the strong ergodic property of unique mixing, when
|q|<1.