title: A constitutive model for unsaturated cemented soils under cyclic loading

abstract:
  On the basis of plastic bounding surface model, the damage theory for
structured soils and unsaturated soil mechanics, an elastoplastic model for
unsaturated loessic soils under cyclic loading has been elaborated. Firstly,
the description of bond degradation in a damage framework is given, linking the
damage of soil's structure to the accumulated strain. The Barcelona Basic Model
(BBM) was considered for the suction effects. The elastoplastic model is then
integrated into a bounding surface plasticity framework in order to model
strain accumulation along cyclic loading, even under small stress levels. The
validation of the proposed model is conducted by comparing its predictions with
the experimental results from multi-level cyclic triaxial tests performed on a
natural loess sampled beside the Northern French railway for high speed train
and about 140 km far from Paris. The comparisons show the capabilities of the
model to describe the behaviour of unsaturated cemented soils under cyclic
loading.


title:
Collisional decoherence in trapped atom interferometers that use
  non-degenerate sources

abstract:
  The coherence time, and thus sensitivity, of trapped atom interferometers
that use non-degenerate gasses are limited by the collisions between the atoms.
An analytic model that describes the effects of collisions between atoms in an
interferometer is developed. It is then applied to an interferometer using a
harmonically trapped non-degenerate atomic gas that is manipulated with a
single set of standing wave laser pulses. The model is used to find the optimal
operating conditions of the interferometer and direct Monte-Carlo simulation of
the interferometer is used to verify the analytic model.


title:
The free energy of the non-isotropic Ising lattice with Brascamp-Kunz
  boundary conditions

abstract:
  The free energy of the finite and non-isotropic Ising lattice with
Brascamp-Kunz boundary conditions is calculated exactly as a series in the
absence of an external magnetic field.


title: A Schanuel property for exponentially transcendental powers

abstract:
  We prove the analogue of Schanuel's conjecture for raising to the power of an
exponentially transcendental real number. All but countably many real numbers
are exponentially transcendental. We also give a more general result for
several powers in a context which encompasses the complex case.


title: The synchrotron boiler and the spectral states of black hole binaries

abstract:
  We study the effects of synchrotron self-absorption on the Comptonising
electron distribution in the magnetised corona of accreting black holes. We
solve the kinetic equations assuming that power is supplied to the coronal
electrons through Coulomb collisions with a population of hot protons and/or
through the injection of non-thermal energetic electrons by some unspecified
acceleration process. We compute numerically the steady state particle
distributions and escaping photon spectra. These numerical simulations confirm
that synchrotron self-absorption, together with e-e Coulomb collisions,
constitute an efficient thermalising mechanism for the coronal electrons. When
compared to the data, they allow us to constrain the magnetic field and
temperature of the hot protons in the corona independently of any dynamical
accretion flow model or geometry. A preliminary comparison with the Low Hard
State (LHS) spectrum of Cygnus X-1 indicates a magnetic field below
equipartition with radiation, suggesting that the corona is not powered through
magnetic field dissipation (as assumed in most accretion disc corona models).
However, in the LHS of Cygnus X-1 and other sources, our results also point
toward proton temperatures substantially lower than what predicted by the
ADAF-like models. In contrast, in the High Soft State (HSS) both the proton
temperature and magnetic field could be much higher. We also show that in both
spectral states the magnetised corona could be powered essentially through
acceleration of non-thermal particles. The main differences between the LHS and
HSS coronal emission can then be understood as the consequence of the much
stronger radiative cooling in the HSS caused by the soft thermal radiation
coming from the geometrically thin accretion disc.


title: The Milne spacetime and the hadronic Rindler horizon

abstract:
  A direct relation between the time dependent Milne geometry and the Rindler
spacetime is shown. Milne's metric corresponds to that one beyond Rindler's
event horizon (in the region $t \succ |x|)$). It was found that the shear
tensor from the dissipative term of the RHIC expanding fireball has the same
structure as that corresponding to the anisotropic fluid from the black hole
interior, even though the latter geometry is curved.


title: Logics for XML

abstract:
  This thesis describes the theoretical and practical foundations of a system
for the static analysis of XML processing languages. The system relies on a
fixpoint temporal logic with converse, derived from the mu-calculus, where
models are finite trees. This calculus is expressive enough to capture regular
tree types along with multi-directional navigation in trees, while having a
single exponential time complexity. Specifically the decidability of the logic
is proved in time 2^O(n) where n is the size of the input formula.
  Major XML concepts are linearly translated into the logic: XPath navigation
and node selection semantics, and regular tree languages (which include DTDs
and XML Schemas). Based on these embeddings, several problems of major
importance in XML applications are reduced to satisfiability of the logic.
These problems include XPath containment, emptiness, equivalence, overlap,
coverage, in the presence or absence of regular tree type constraints, and the
static type-checking of an annotated query.
  The focus is then given to a sound and complete algorithm for deciding the
logic, along with a detailed complexity analysis, and crucial implementation
techniques for building an effective solver. Practical experiments using a full
implementation of the system are presented. The system appears to be efficient
in practice for several realistic scenarios.
  The main application of this work is a new class of static analyzers for
programming languages using both XPath expressions and XML type annotations
(input and output). Such analyzers allow to ensure at compile-time valuable
properties such as type-safety and optimizations, for safer and more efficient
XML processing.


title: Hyperentanglement of two photons in three degrees of freedom

abstract:
  A 6-qubit hyperentangled state has been realized by entangling two photons in
three degrees of freedom. These correspond to the polarization, the
longitudinal momentum and the indistinguishable emission produced by a
2-crystal system operating with Type I phase matching in the spontaneous
parametric down conversion regime. The state has been characterized by a
chained interferometric apparatus and its complete entangled nature has been
tested by a novel witness criterium specifically introduced for hyperentangled
states. The experiment represents the first realization of a genuine
hyperentangled state with the maximum entanglement between the two particles
allowed in the given Hilbert space.


title:
Parity doubling in the high baryon spectrum: near-degenerate three-quark
  quartets

abstract:
  We report on the first calculation of excited baryons with a chirally
symmetric Hamiltonian, modeled after Coulomb gauge QCD (or upgraded from the
Cornell meson potential model to a field theory in all of Fock-space) showing
the insensitivity to chiral symmetry breaking. As has recently been understood,
this leads to doubling between two hadrons of equal spin and opposite parity.
As a novelty we show that three-quark, for example Delta states, group into
quartets with two states of each parity, all four states having equal angular
momentum J. Diagonalizing the chiral charge expressed in terms of quarks we
show that the quartet is slightly split into two parity doublets by the tensor
force, all splittings decreasing to zero high in the spectrum. Our specific
calculation is for the family of maximum-spin excitations of the Delta baryon.
We provide a model estimate of the experimental accuracy needed to establish
Chiral Symmetry Restoration in the high spectrum.
  We suggest that a measurement of masses of high-partial wave Delta resonances
with an accuracy of 50 MeV should be sufficient to unambiguously establish the
approximate degeneracy, and test the concept of running quark mass in the
infrared.


title:
On the nature of striped phases: Striped phases as a stage of "melting"
  of 2D crystals

abstract:
  We discuss striped phases as a state of matter intermediate between two
extreme states: a crystalline state and a segregated state. We argue that this
state is very sensitive to weak interactions, compared to those stabilizing a
crystalline state, and to anisotropies. Moreover, under suitable conditions a
2D system in a striped phase decouples into (quasi) 1D chains. These
observations are based on results of our studies of an extension of a
microscopic quantum model of crystallization, proposed originally by Kennedy
and Lieb.


title:
Superdiffusive Heat Transport in a class of Deterministic
  One-Dimensional Many-Particle Lorentz gases

abstract:
  We study heat transport in a one-dimensional chain of a finite number $N$ of
identical cells, coupled at its boundaries to stochastic particle reservoirs.
At the center of each cell, tracer particles collide with fixed scatterers,
exchanging momentum. In a recent paper, \cite{CE08}, a spatially continuous
version of this model was derived in a scaling regime where the scattering
probability of the tracers is $\gamma\sim1/N$, corresponding to the Grad limit.
A Boltzmann type equation describing the transport of heat was obtained. In
this paper, we show numerically that the Boltzmann description obtained in
\cite{CE08} is indeed a bona fide limit of the particle model. Furthermore, we
also study the heat transport of the model when the scattering probability is
one, corresponding to deterministic dynamics. At a coarse grained level the
model behaves as a persistent random walker with a broad waiting time
distribution and strong correlations associated to the deterministic
scattering. We show, that, in spite of the absence of global conserved
quantities, the model leads to a superdiffusive heat transport.


title:
Centrality Dependence of Strangeness Enhancement in Ultrarelativistic
  Heavy Ion Collisions - a Core-Corona Effect

abstract:
  In ultrarelativistic heavy ion collisions, the multiplicity of multi-strange
baryons per participating nucleon increases with centrality in a different
fashion for different systems and energies. At RHIC, for copper+copper (CuCu)
collisions the increase is much steeper than for gold-gold (AuAu) collisions.
We show that this system size dependence is due to a core-corona effect: the
relative importance of the corona as compared to the core (thermalized matter)
contribution varies and the contribution of a corona nucleon to the
multiplicity differs from that of a core nucleon. $\phi$ mesons follow in
principle the same trend, but the difference between core and corona
multiplicity is relatively small, and therefore the CuCu and AuAu results are
quite similar. This simple geometrical explanation makes also a strong case in
favor of the validity of Glauber geometry in the peripheral regions of
ultrarelativistic heavy ion collisions, which is crucial for understanding the
early evolution of the system.


title:
High-Mobility Few-Layer Graphene Field Effect Transistors Fabricated on
  Epitaxial Ferroelectric Gate Oxides

abstract:
  The carrier mobility \mu of few-layer graphene (FLG) field-effect transistors
increases ten-fold when the SiO_2 substrate is replaced by single-crystal
epitaxial Pb(Zr_0.2Ti_0.8)O_3 (PZT). In the electron-only regime of the FLG,
\mu reaches 7x10^4 cm^2/Vs at 300K for n = 2.4x10^12/cm^2, 70% of the intrinsic
limit set by longitudinal acoustic (LA) phonons; it increases to 1.4x10^5
cm^2/Vs at low temperature. The temperature-dependent resistivity \rho(T)
reveals a clear signature of LA phonon scattering, yielding a deformation
potential D = 7.8+/-0.5 eV.


title: Renormalization group and bound states

abstract:
  Similarity renormalization group procedure identifies the role of bound
states in the low-energy rate of change of effective coupling constant in a
model Hamiltonian with asymptotic freedom.


title:
Cosmic-ray knee and diffuse gamma, e+ and pbar fluxes from collisions of
  cosmic rays with dark matter

abstract:
  In models with extra dimensions the fundamental scale of gravity M_D could be
of order TeV. In that case the interaction cross section between a cosmic
proton of energy E and a dark matter particle \chi will grow fast with E for
center of mass energies \sqrt{2m_\chi E} above M_D, and it could reach 1 mbarn
at E\approx 10^9 GeV. We show that these gravity-mediated processes would break
the proton and produce a diffuse flux of particles/antiparticles, while
boosting \chi with a fraction of the initial proton energy. We find that the
expected cross sections and dark matter densities are not enough to produce an
observable asymmetry in the flux of the most energetic (extragalactic) cosmic
rays. However, we propose that unsuppressed TeV interactions may be the origin
of the knee observed in the spectrum of galactic cosmic rays. The knee would
appear at the energy threshold for the interaction of dark matter particles
with cosmic protons trapped in the galaxy by \muG magnetic fields, and it would
imply a well defined flux of secondary antiparticles and TeV gamma rays.


title:
Interplay between magnetic properties and Fermi surface nesting in iron
  pnictides

abstract:
  The wave-vector q and doping (x,y) dependences of the magnetic energy, iron
moment, and effective exchange interactions in LaFeAsO{1-x}F{x} and
Ba{1-2y}K{2y}Fe2As2 are studied by self-consistent LSDA calculations for
co-planar spin spirals. For the undoped compounds (x=0, y=0), the minimum of
the calculated total energy, E(q), is for q corresponding to stripe
antiferromagnetic order. Already at low levels of electron doping (x), this
minimum becomes flat in LaFeAsO{1-x}F{x} and for x>=5, it shifts to an
incommensurate q. In Ba{1-2y}K{2y}Fe2As2, stripe order remains stable for hole
doping up to y=0.3. These results are explained in terms of the band structure.
The magnetic interactions cannot be accurately described by a simple classical
Heisenberg model and the effective exchange interactions fitted to E(q) depend
strongly on doping. The doping dependence of the E(q) curves is compared with
that of the noninteracting magnetic susceptibility for which similar trends are
found.


title: Relativistic multirank interaction kernels of the neutron-proton system

abstract:
  The multirank separable kernels of the neutron-proton interaction for
uncoupled $S$ and $P$ partial waves (with the total angular momentum $J$=0,1)
are proposed. Two different methods of a relativistic generalization of
initially nonrelativistic form factors parametrizing the kernel are considered.
Using the constructed kernels the experimental data for phase shifts in the
elastic neutron-proton scattering for the laboratory energy up to 3 GeV and
low-energy parameters are described. The comparison of our results with other
model calculations are presented.


title: Spin Dynamics in the Magnetoelectric Effect LiCoPO$_4$ Compound

abstract:
  Inelastic neutron scattering (INS) experiments were performed to investigate
the spin dynamics in magnetoelectric effect (ME) LiCoPO$_4$ single crystals.
Weak dispersion was detected in the magnetic excitation spectra along the three
principal crystallographic axes measured around the (0 1 0) magnetic
reflection. Analysis of the data using linear spin-wave theory indicate that
single-ion anisotropy in LiCoPO$_4$ is as important as the strongest
nearest-neighbor exchange coupling. Our results suggest that Co$^{2+}$
single-ion anisotropy plays an important role in the spin dynamics of
LiCoPO$_4$ and must be taken into account in understanding its physical
properties. High resolution INS measurements reveal an anomalous low energy
excitation that we hypothesize may be related to the magnetoelectric effect of
LiCoPO$_4$.


title:
The simplest problem in the collective dynamics of neural networks: Is
  synchrony stable?

abstract:
  For spiking neural networks we consider the stability problem of global
synchrony, arguably the simplest non-trivial collective dynamics in such
networks. We find that even this simplest dynamical problem -- local stability
of synchrony -- is non-trivial to solve and requires novel methods for its
solution. The dynamics in the vicinity of the synchronous state is determined
by a multitude of linear operators, in contrast to a single stability matrix in
conventional linear stability theory. This unusual property qualitatively
depends on network topology and may be neglected for globally coupled
homogeneous networks. For generic networks, however, the number of operators
increases exponentially with the size of the network. We present methods to
treat this multi-operator problem exactly. First, based on the Gershgorin and
Perron-Frobenius theorems, we derive bounds on the eigenvalues that provide
important information about the synchronization process but are not sufficient
to establish the asymptotic stability or instability of the synchronous state.
We then present a complete analysis of asymptotic stability for topologically
strongly connected networks using simple graph-theoretical considerations. For
inhibitory interactions between dissipative (leaky) oscillatory neurons the
synchronous state is stable, independent of the parameters and the network
connectivity. These results indicate that pulse-like interactions play a
profound role in network dynamical systems, and in particular in the dynamics
of biological synchronization, unless the coupling is homogeneous and
all-to-all.


title:
Quantum theory of spontaneous emission in multilayer dielectric
  structures

abstract:
  We present a fully quantum-electrodynamical formalism suitable to evaluate
the spontaneous emission rate and pattern from a dipole embedded in a
non-absorbing and lossless multilayer dielectric structure. In the model here
developed the electromagnetic field is quantized by a proper choice of a
complete and orthonormal set of classical spatial modes, which consists of
guided and radiative (partially and fully) states. In particular, by choosing a
set of radiative states characterized by a single outgoing component, we get
rid of the problem related to the quantum interference between different
outgoing modes, which arises when the standard radiative basis is used to
calculate spontaneous emission patterns. After the derivation of the local
density of states, the analytical expressions for the emission rates are
obtained within the framework of perturbation theory. First we apply our model
to realistic Silicon-based structures such as a single Silicon/air interface
and a Silicon waveguide in both the symmetric and asymmetric configurations.
Then, we focus on the analysis of the spontaneous emission process in a
silicon-on-insulator (SOI) Slot waveguide (a 6 layers model structure) doped
with erbium ions (emitting at the telecom wavelength). In this latter case we
find a very good agreement with the experimental evidence [M. Galli et al.,
Appl. Phys. Lett. 89, 241114 (2006)] of an enhanced TM/TE photoluminescence
signal. Hence, this model is relevant to study the spontaneous emission in
Silicon-based multilayer structures which nowadays play a fundamental role for
the development of highly integrated multifunctional devices.


title:
Stochastic optimization of a cold atom experiment using a genetic
  algorithm

abstract:
  We employ an evolutionary algorithm to automatically optimize different
stages of a cold atom experiment without human intervention. This approach
closes the loop between computer based experimental control systems and
automatic real time analysis and can be applied to a wide range of experimental
situations. The genetic algorithm quickly and reliably converges to the most
performing parameter set independent of the starting population. Especially in
many-dimensional or connected parameter spaces the automatic optimization
outperforms a manual search.


title: The shape of disorder broadened Landau subbands in graphene

abstract:
  Density of states (DOS) of graphene under a high uniform magnetic field and
white-noise random potential is numerically calculated. The disorder broadened
zero-energy Landau band has a Gaussian shape whose width is proportional to the
random potential variance and the square root of magnetic field. Wegner-type
calculation is used to justify the results.


title:
Laboratory investigations of the interaction between benzene and bare
  silicate grain surfaces

abstract:
  Experimental results on the thermal desorption of benzene (C6H6) from
amorphous silica (SiO2) are presented. The amorphous SiO2 substrate was imaged
using atomic force microscopy (AFM), revealing a surface morphology reminiscent
of that of interplanetary dust particles (IDPs). Temperature programmed
desorption (TPD) experiments were conducted for a wide range of C6H6 exposures,
yielding information on both C6H6-SiO2 interactions and the C6H6-C6H6
interactions present in the bulk C6H6 ice. The low coverage experiments reveal
complicated desorption behaviour that results both from porosity and roughness
in the SiO2 substrate, and repulsive interactions between C6H6 molecules.
Kinetic parameters were obtained through a combination of direct analysis of
the TPD traces and kinetic modelling, demonstrating the coverage dependence of
both desorption energy and pre-exponential factor. Experiments were also
performed whereby the pores were blocked by pre-exposure of the SiO2 to water
vapour. C6H6 was observed to be adsorbed preferentially on the SiO2 film not
covered by H2O at the temperature at which these experiments were performed.
This observation means that intermolecular repulsion likely becomes important
at smaller C6H6 exposures on grains with a H2O mantle. Kinetic modelling of
C6H6 multilayer desorption yields kinetic parameters in good agreement with
previous studies, with the SiO2 having little impact on the desorption beyond
the first few layers.


title: Tuning improved anisotropic actions in lattice perturbation theory

abstract:
  We discuss the tuning of the anisotropic clover action and Symanzik-improved
gauge action in lattice perturbation theory. The fermion action is constructed
from stout-smeared spatial links, which complicates the calculation
considerably. In addition, the full quark-mass dependence of the action
parameters is included in this study. We present results for the fermion and
gauge aspect ratios for varying bare aspect ratios, quark masses and smearing
parameters.


title: Conformal Structure of Minimal Surfaces with Finite Topology

abstract:
  In this paper, we show that a complete embedded minimal surface in $\Real^3$
with finite topology and one end is conformal to a once-punctured compact
Riemann surface. Moreover, using the conformality and embeddedness, we examine
the Weierstrass data and conclude that every such surface has Weierstrass data
asymptotic to that of the helicoid. More precisely, if $g$ is the stereographic
projection of the Gauss map, then in a neighborhood of the puncture, $g(p) =
\exp(i\alpha z(p) + F(p))$, where $\alpha \in \Real$, $z=x_3+ix_3^*$ is a
holomorphic coordinate defined in this neighborhood and $F(p)$ is holomorphic
in the neighborhood and extends over the puncture with a zero there. This
further implies that the end is actually Hausdorff close to a helicoid.


title:
Inherent correlations between thermodynamics and statistic physics in
  extensive and nonextensive systems

abstract:
  With the help of a general expression of the entropies in extensive and
nonextensive systems, some important relations between thermodynamics and
statistical mechanics are revealed through the views of thermodynamics and
statistic physics. These relations are proved through the MaxEnt approach once
again. It is found that for a reversible isothermal process, the information
contained in the first and second laws of thermodynamics and the MaxEnt
approach is equivalent. Moreover, these relations are used to derive the
probability distribution functions in nonextensive and extensive statistics and
calculate the generalized forces of some interesting systems. The results
obtained are of universal significance.


title: Higher localized analytic indices and strict deformation quantization

abstract:
  This paper is concerned with the localization of higher analytic indices for
Lie groupoids. Let $\gr$ be a Lie groupoid with Lie algebroid $A\gr$. Let
$\tau$ be a (periodic) cyclic cocycle over the convolution algebra $\cg$. We
say that $\tau$ can be localized if there is a correspondence
K^0(A^*\gr)\stackrel{Ind_{\tau}}{\longrightarrow}\mathbb{C} satisfying
$Ind_{\tau}(a)=< ind D_a,\tau>$ (Connes pairing). In this case, we call
$Ind_{\tau}$ the higher localized index associated to $\tau$. In {Ca4} we use
the algebra of functions over the tangent groupoid introduced in {Ca2}, which
is in fact a strict deformation quantization of the Schwartz algebra
$\sw(A\gr)$, to prove the following results: \item Every bounded continuous
cyclic cocycle can be localized. \item If $\gr$ is {\'e}tale, every cyclic
cocycle can be localized. We will recall this results with the difference that
in this paper, a formula for higher localized indices will be given in terms of
an asymptotic limit of a pairing at the level of the deformation algebra
mentioned above. We will discuss how the higher index formulas of
Connes-Moscovici, Gorokhovsky-Lott fit in this unifying setting.


title:
Thermodynamical approaches to efficient sympathetic cooling in ultracold
  Fermi-Bose atomic mixtures

abstract:
  We discuss the cooling efficiency of ultracold Fermi-Bose mixtures in
species-selective traps using a thermodynamical approach. The dynamics of
evaporative cooling trajectories is analyzed in the specific case of
bichromatic optical dipole traps also taking into account the effect of partial
spatial overlap between the Fermi gas and the thermal component of the Bose
gas. We show that large trapping frequency ratios between the Fermi and the
Bose species allow for the achievement of a deeper Fermi degeneracy,
consolidating in a thermodynamic setting earlier arguments based on more
restrictive assumptions. In particular, we confirm that the minimum temperature
of the mixture is obtained at the crossover between boson and fermion heat
capacities, and that below such a temperature sympathetic cooling vanishes.
When the effect of partial overlap is taken into account, optimal sympathetic
cooing of the Fermi species may be achieved by properly tuning the relative
trapping strength of the two species in a time-dependent fashion.
Alternatively, the dimensionality of the trap in the final stage of cooling can
be changed by increasing the confinement strength, which also results in a
crossover of the heat capacities at deeper Fermi degeneracies. This technique
may be extended to Fermi-Bose degenerate mixtures in optical lattices.


title: Probing eV-scale axions with CAST

abstract:
  We have searched for solar axions or other pseudoscalar particles that couple
to two photons by using the CERN Axion Solar Telescope (CAST) setup. Whereas we
previously have reported results from CAST with evacuated magnet bores (Phase
I), setting limits on lower mass axions, here we report results from CAST where
the magnet bores were filled with \hefour gas (Phase II) of variable pressure.
The introduction of gas generated a refractive photon mass $m_\gamma$, thereby
achieving the maximum possible conversion rate for those axion masses \ma that
match $m_\gamma$. With 160 different pressure settings we have scanned \ma up
to about 0.4 eV, taking approximately 2 h of data for each setting. From the
absence of excess X-rays when the magnet was pointing to the Sun, we set a
typical upper limit on the axion-photon coupling of $\gag\lesssim 2.17\times
10^{-10} {\rm GeV}^{-1}$ at 95% CL for $\ma \lesssim 0.4$ eV, the exact result
depending on the pressure setting. The excluded parameter range covers
realistic axion models with a Peccei-Quinn scale in the neighborhood of $f_{\rm
a}\sim10^{7}$ GeV. Currently in the second part of CAST Phase II, we are
searching for axions with masses up to about 1.2 eV using \hethree as a buffer
gas.


title:
Faddeev-type calculations of few-body nuclear reactions including
  Coulomb interaction

abstract:
  The method of screening and renormalization is used to include the Coulomb
interaction between the charged particles in the description of few-body
nuclear reactions. Calculations are done in the framework of Faddeev-type
equations in momentum-space. The reliability of the method is demonstrated. The
Coulomb effect on observables is discussed.


title: Model- and calibration-independent test of cosmic acceleration

abstract:
  We present a calibration-independent test of the accelerated expansion of the
universe using supernova type Ia data. The test is also model-independent in
the sense that no assumptions about the content of the universe or about the
parameterization of the deceleration parameter are made and that it does not
assume any dynamical equations of motion. Yet, the test assumes the universe
and the distribution of supernovae to be statistically homogeneous and
isotropic. A significant reduction of systematic effects, as compared to our
previous, calibration-dependent test, is achieved. Accelerated expansion is
detected at significant level (4.3 sigma in the 2007 Gold sample, 7.2 sigma in
the 2008 Union sample) if the universe is spatially flat. This result depends,
however, crucially on supernovae with a redshift smaller than 0.1, for which
the assumption of statistical isotropy and homogeneity is less well
established.


title: Skewness Premium with L\'evy Processes

abstract:
  We study the skewness premium (SK) introduced by Bates (1991) in a general
context using L\'evy Processes. Under a symmetry condition Fajardo and Mordecki
(2006) obtain that SK is given by the Bate's $x%$ rule. In this paper we study
SK under the absence of that symmetry condition. More exactly, we derive
sufficient conditions for SK to be positive, in terms of the characteristic
triplet of the L\'evy Process under the risk neutral measure.


title: Optical Lenses for Atomic Beams

abstract:
  Superpositions of paraxial laser beam modes to generate atom-optical lenses
based on the optical dipole force are investigated theoretically. Thin, wide,
parabolic, cylindrical and circular atom lenses with numerical apertures much
greater than those reported in the literature to date can be synthesized. This
superposition approach promises to make high quality atom beam imaging and
nano-deposition feasible.


title: Supporting degrees of multi-graded local cohomolgoy modules

abstract:
  For a finitely generated graded module $M$ over a positively-graded
commutative Noetherian ring $R$, the second author established in 1999 some
restrictions, which can be formulated in terms of the Castelnuovo regularity of
$M$ or the so-called $a^*$-invariant of $M$, on the supporting degrees of a
graded-indecomposable graded-injective direct summand, with associated prime
ideal containing the irrelevant ideal of $R$, of any term in the minimal
graded-injective resolution of $M$. Earlier, in 1995, T. Marley had established
connections between finitely graded local cohomology modules of $M$ and local
behaviour of $M$ across $\Proj(R)$. The purpose of this paper is to present
some multi-graded analogues of the above-mentioned work.


title: A quantum interface between light and nuclear spins in quantum dots

abstract:
  The coherent coupling of flying photonic qubits to stationary matter-based
qubits is an essential building block for quantum communication networks. We
show how such a quantum interface can be realized between a traveling-wave
optical field and the polarized nuclear spins in a singly charged quantum dot
strongly coupled to a high-finesse optical cavity. By adiabatically eliminating
the electron a direct effective coupling is achieved. Depending on the laser
field applied, interactions that enable either write-in or read-out are
obtained.


title: Zeno Quantum Gates in Semiconductor Quantum Dots

abstract:
  We propose a scheme for a two-qubit conditional phase gate by quantum Zeno
effect with semiconductor quantum dots. The system consists of two charged dots
and one ancillary dot that can perform Rabi oscillations under a resonant laser
pulse. The quantum Zeno effect is induced by phonon-assisted exciton relaxation
between the ancillary dot and the charged dots, which is equivalent to a
continuous measurement. We solve analytically the master equation and simulate
the dynamics of the system using a realistic set of parameters. In contrast to
standard schemes, larger phonon relaxation rates increase the fidelity of the
operations.


title:
Recent updates on the ArDM project: A Liquid Argon TPC for Dark Matter
  Detection

abstract:
  ArDM is a new-generation WIMP detector which will measure simultaneously
light and charge from scintillation and ionization of liquid argon. Our goal is
to construct, characterize and operate a 1 ton liquid argon underground
detector. The project relies on the possibility to extract the electrons
produced by ionization from the liquid into the gas phase of the detector, to
amplify and read out with Large Electron Multipliers detectors. Argon VUV
scintillation light has to be converted with wavelength shifters such as
TetraPhenyl Butadiene in order to be detected by photomultipliers with bialkali
photocathodes. We describe the status of the LEM based charge readout and light
readout system R&D and the first light readout tests with warm and cold argon
gas in the full size detector.


title: Sharp large deviations for the fractional Ornstein-Uhlenbeck process

abstract:
  We investigate the sharp large deviation properties of the energy and the
maximum likelihood estimator for the Ornstein-Uhlenbeck process driven by a
fractional Brownian motion with Hurst index greater than one half.


title: Model Categories and Quantum Gravity

abstract:
  We propose a mathematically concrete way of modelling the suggestion that in
quantum gravity the spacetime disappears, replacing it with a discrete
approximation to the causal path space described as an object in a model
category. One of the versions of our models appears as a thickening of
spacetime, which we interpret as a formulation of relational geometry. Avenues
toward constructing an actual quantum theory of gravity on our models are given
a preliminary exploration.


title: Excision boundary conditions for the conformal metric

abstract:
  Shibata, Ury\=u and Friedman recently suggested a new decomposition of
Einstein's equations that is useful for constructing initial data. In contrast
to previous decompositions, the conformal metric is no longer treated as a
freely-specifiable variable, but rather is determined as a solution to the
field equations. The new set of freely-specifiable variables includes only
time-derivatives of metric quantities, which makes this decomposition very
attractive for the construction of quasiequilibrium solutions. To date, this
new formalism has only been used for binary neutron stars. Applications
involving black holes require new boundary conditions for the conformal metric
on the domain boundaries. In this paper we demonstrate how these boundary
conditions follow naturally from the conformal geometry of the boundary
surfaces and the inherent gauge freedom of the conformal metric.


title: The TeV emitter structure in LS 5039

abstract:
  LS 5039 is an X-ray binary detected at very high energies. Along the orbit,
there is a significant detection even during the superior conjunction of the
compact object, when very large gamma-ray opacities are expected.
Electromagnetic cascades, which may make the system more transparent to
gamma-rays, are hardly efficient for reasonable magnetic fields in the massive
star surroundings. A jet-like flow could transport energy to regions where the
photon-photon absorption is much lower and the TeV radiation is not so severely
absorbed. Otherwise, in the standard pulsar scenario for LS 5039, the emitter
would be located between the star and the compact object, which would imply the
violation of the observational constraints at X-rays.


title:
The Gravitational-Electromagnetic Analogy: A Possible Solution to the
  Vacuum-Energy and Dark-Energy Problems

abstract:
  There is a set of first-order differential equations for the curvature tensor
in general relativity (the curvature equations or CEs for short) that are
strikingly similar to the Maxwell equations of electrodynamics. This paper
considers whether Mother Nature may have used the same basic pattern for her
laws of gravitation and electrodynamics, in which case the CEs might be viewed
as the field equations of gravitation in place of Einstein's equation. This is
not a new theory of gravitation (because the curvature equations are derivable
from Einstein's equation), but rather is a mild reinterpretation of general
relativity that solves the vacuum-energy problem and the dark-energy problem of
cosmology. The results of this paper allow one to understand how the effective
energy density of the observed cosmological constant can be so vastly smaller
than estimates of the vacuum energy of quantum fields and why the vacuum energy
of quantum fields does not contribute as a source of curvature.


title:
A version of geometric motivic integration that specializes to p-adic
  integration via point counting

abstract:
  We give a version of geometric motivic integration that specializes to p-adic
integration via point counting. This has been done before for stable sets; we
extend this to more general sets. The main problem in doing this is that it
requires to take limits, hence the measure will have to take values in a
completion of the (localized) Grothendieck ring of varieties. The standard
choice is to complete with respect to the dimension filtration; however, since
the point counting homomorphism is not continuous with respect to this topology
we have to use a stronger one. The first part of the paper is devoted to
defining this topology; in the second part we will then see that many of the
standard constructions of geometric motivic integration work also in this
setting.


title: Hadron form factors from sum rules for vacuum-to-hadron correlators

abstract:
  We analyse the extraction of the bound-state form factor from
vacuum-to-hadron correlator, which is the basic object for the calculation of
hadron form factors in the method of light-cone sum rules in QCD. We study this
correlator in quantum mechanics, calculate it exactly, and derive the
corresponding OPE. We then apply the standard procedures of QCD sum rules to
isolate the ground-state form factor from this correlator. We demonstrate that
fixing the effective continuum threshold, one of the key ingredients of the
sum-rule calculation of bound-state parameters, poses a serious problem for sum
rules based on vacuum-to-hadron correlators.


title: Phonon dynamics in Sr0.6K0.4Fe2As2 and Ca0.6Na0.4Fe2As2

abstract:
  We report inelastic neutron scattering measurements of the phonon
density-of-states in superconducting Sr0.6K0.4Fe2As2 (Tc=30 K) and
Ca0.6Na0.4Fe2As2 (Tc=18 K). Compared with the parent compound BaFe2As2 doping
affects mainly the lower and intermediate frequency part of the vibrations.
Mass effects and lattice contraction cannot explain these changes. A lattice
dynamical model has been used to identify the character of the various phonon
bands. Softening of phonon modes below 10 meV has been observed in both samples
on cooling from 300 K to 140 K. In the Ca doped compound the softening amounts
to about 1 meV while for the Sr doped compound the softening is about 0.5 meV.
There is no appreciable change in the phonon density of states when crossing
Tc.


title:
Coupled Mode Equations and Gap Solitons for the 2D Gross-Pitaevskii
  equation with a non-separable periodic potential

abstract:
  Gap solitons near a band edge of a spatially periodic nonlinear PDE can be
formally approximated by solutions of Coupled Mode Equations (CMEs). Here we
study this approximation for the case of the 2D Periodic Nonlinear
Schr\"{o}dinger / Gross-Pitaevskii Equation with a non-separable potential of
finite contrast. We show that unlike in the case of separable potentials [T.
Dohnal, D. Pelinovsky, and G. Schneider, J. Nonlin. Sci. {\bf 19}, 95--131
(2009)] the CME derivation has to be carried out in Bloch rather than physical
coordinates. Using the Lyapunov-Schmidt reduction we then give a rigorous
justification of the CMEs as an asymptotic model for reversible non-degenerate
gap solitons and even potentials and provide $H^s$ estimates for this
approximation. The results are confirmed by numerical examples including some
new families of CMEs and gap solitons absent for separable potentials.


title: Cooling ultracold bosons in optical lattices by spectral transform

abstract:
  It is shown theoretically how to directly obtain the energy distribution of a
weakly interacting gas of bosons confined in an optical lattice in the
tight-binding limit. This is accomplished by adding a linear potential to a
suitably prepared lattice, and allowing the gas to evolve under the influence
of the total potential. After a prescribed time, a spectral transform is
effected where each (highly non-local) energy state is transformed into a
distinct site of the lattice, thus allowing the energy distribution to be
(non-destructively) imaged in real space. Evolving for twice the time returns
the atoms to their initial state. The results suggest efficient methods to both
measure the temperature in situ, as well as to cool atoms within the lattice:
after applying the spectral transform one simply needs to remove atoms from all
but a few lattice sites. Using exact numerical calculations, the effects of
interactions and errors in the application of the lattice are examined.


title: Dispersion and fidelity in quantum interferometry

abstract:
  We consider Mach-Zehnder and Hong-Ou-Mandel interferometers with nonclassical
states of light as input, and study the effect that dispersion inside the
interferometer has on the sensitivity of phase measurements. We study in detail
a number of different one- and two-photon input states, including Fock, dual
Fock, N00N states, and photon pairs from parametric downconversion. Assuming
there is a phase shift $\phi_0$ in one arm of the interferometer, we compute
the probabilities of measurement outcomes as a function of $\phi_0$, and then
compute the Shannon mutual information between $\phi_0$ and the measurements.
This provides a means of quantitatively comparing the utility of various input
states for determining the phase in the presence of dispersion. In addition, we
consider a simplified model of parametric downconversion for which
probabilities can be explicitly computed analytically, and which serves as a
limiting case of the more realistic downconversion model.


title: Quadratic functors on pointed categories

abstract:
  We study polynomial functors of degree 2, called quadratic, with values in
the category of abelian groups $Ab$, and whose source category is an arbitrary
category $\C$ with null object such that all objects are colimits of copies of
a generating object $E$ which is small and regular projective; this includes
all pointed algebraic varieties. More specifically, we are interested in such
quadratic functors $F$ from $\C$ to $Ab$ which preserve filtered colimits and
suitable coequalizers; one may take reflexive ones if $\C$ is Mal'cev and Barr
exact. A functorial equivalence is established between such functors $F:\C\to
Ab$ and certain minimal algebraic data which we call quadratic $\C$-modules:
these involve the values on $E$ of the cross-effects of $F$ and certain
structure maps generalizing the second Hopf invariant and the Whitehead
product. Applying this general result to the case where $E$ is a cogroup these
data take a particularly simple form. This application extends results of Baues
and Pirashvili obtained for $\C$ being the category of groups or of modules
over some ring; here quadratic $\C$-modules are equivalent with abelian square
groups or quadratic $R$-modules, respectively.


title: A generalisation of Schramm's formula for SLE(2)

abstract:
  The scaling limit of planar loop-erased random walks is described by a
stochastic Loewner evolution with parameter kappa=2. In this note SLE(2) in the
upper half-plane H minus a simply-connected compact subset K of H is studied.
As a main result, the left-passage probability with respect to K is explicitly
determined.


title: The law of series

abstract:
  We consider an ergodic process on finitely many states, with positive
entropy. Our first main result asserts that the distribution function of the
normalized waiting time for the first visit to a small (i.e., over a long
block) cylinder set $B$ is, for majority of such cylinders and up to epsilon,
dominated by the exponential distribution function $1-e^{-t}$. That is, the
occurrences of so understood "rare event" $B$ along the time axis can appear
either with gap sizes of nearly exponential distribution (like in the
independent Bernoulli process), or they "attract" each-other. Our second main
result states that a {\it typical} ergodic process of positive entropy has the
following property: the distribution functions of the normalized hitting times
for the majority of cylinders $B$ of lengths $n'$ converge to zero along a \sq\
$n'$ whose upper density is 1. The occurrences of such a cylinder $B$ "strongly
attract", i.e., they appear in "series" of many frequent repetitions separated
by huge gaps of nearly complete absence.
  These results, when properly and carefully interpreted, shed some new light,
in purely statistical terms, independently from physics, on a century old (and
so far rather avoided by serious science) common-sense phenomenon known as {\it
the law of series}, asserting that rare events in reality, once occurred, have
a mysterious tendency for untimely repetitions.


title: Quasi-isometries between visual hyperbolic spaces

abstract:
  We prove that a PQ-symmetric homeomorphism between two complete metric spaces
can be extended to a quasi-isometry between their hyperbolic approximations.
  This result is used to prove that two visual Gromov hyperbolic spaces are
quasi-isometric if and only if there is a PQ-symmetric homeomorphism between
their boundaries.


title:
Optimal spin-quantization axes for the polarization of dileptons with
  large transverse momentum

abstract:
  The leading-order parton processes that produce a dilepton with large
transverse momentum predict that the transverse polarization should increase
with the transverse momentum for almost any choice of the quantization axis for
the spin of the virtual photon. The rate of approach to complete transverse
polarization depends on the choice of spin quantization axis. We propose axes
that optimize that rate of approach. They are determined by the momentum of the
dilepton and the direction of the jet that provides most of the balancing
transverse momentum.


title: Strong NP-Hardness of the Quantum Separability Problem

abstract:
  Given the density matrix rho of a bipartite quantum state, the quantum
separability problem asks whether rho is entangled or separable. In 2003,
Gurvits showed that this problem is NP-hard if rho is located within an inverse
exponential (with respect to dimension) distance from the border of the set of
separable quantum states. In this paper, we extend this NP-hardness to an
inverse polynomial distance from the separable set. The result follows from a
simple combination of works by Gurvits, Ioannou, and Liu. We apply our result
to show (1) an immediate lower bound on the maximum distance between a bound
entangled state and the separable set (assuming P != NP), and (2) NP-hardness
for the problem of determining whether a completely positive trace-preserving
linear map is entanglement-breaking.


title:
Logarithmic dimension bounds for the maximal function along a polynomial
  curve

abstract:
  Let M denote the maximal function along the polynomial curve
p(t)=(t,t^2,...,t^d) in R^d: M(f)=sup_{r>0} (1/2r) \int_{|t|<r} |f(x-p(t))| dt.
We show that the L^2-norm of this operator grows at most logarithmically with
the parameter d: ||M||_2 < c log d ||f||_2, where c>0 is an absolute constant.
The proof depends on the explicit construction of a "parabolic" semi-group of
operators which is a mixture of stable semi-groups.


title:
Spontaneous clustering in theoretical and some empirical stationary
  processes

abstract:
  In a stationary ergodic process, clustering is defined as the tendency of
events to appear in series of increased frequency separated by longer breaks.
Such behavior, contradicting the theoretical "unbiased behavior" with
exponential distribution of the gaps between appearances, is commonly observed
in experimental processes and often difficult to explain. In the last section
we relate one such empirical example of clustering, in the area of marine
technology. In the theoretical part of the paper we prove, using ergodic theory
and the notion of category, that clustering (even very strong) is in fact
typical for "rare events" defined as long cylinder sets in processes generated
by a finite partition of an arbitrary (infinite aperiodic) ergodic measure
preserving transformation.


title: GammeV: a milli-eV particle search at Fermilab

abstract:
  GammeV is an experiment conducted at Fermilab that employs the light shining
through a wall technique to search for axion-like particles and employs a
particle in a jar technique to search for dilaton-like chameleon particles. We
obtain limits on the coupling of photons to an axion-like particle that extend
previous limits for both scalars and pseudoscalars in the milli-eV mass range.
We are able to exclude the axion-like particle interpretation of the anomalous
PVLAS 2006 result by more than 5 standard deviations. We also present results
on a search for chameleons and set limits on their possible coupling to
photons.


title: Constructing Stein manifolds after Eliashberg

abstract:
  A unified summary is given of the existence theory of Stein manifolds in all
dimensions, based on published and pending literature. Eliashberg's
characterization of manifolds admitting Stein structures requires an extra
delicate hypothesis in complex dimension 2, which can be eliminated by passing
to the topological setting and invoking Freedman theory. The situation is quite
similar if one asks which open subsets of a fixed complex manifold can be made
Stein by an isotopy. As an application of these theorems, one can construct
uncountably many diffeomorphism types of exotic R^4's realized as Stein open
subsets of C^2 (i.e. domains of holomorphy). More generally, every domain of
holomorphy in C^2 is topologically isotopic to other such domains realizing
uncountably many diffeomorphism types. Any tame n-complex in a complex
n-manifold can be isotoped to become a nested intersection of Stein open
subsets, provided the isotopy is topological when n=2. In the latter case, the
Stein neighborhoods are homeomorphic, but frequently realize uncountably many
diffeomorphism types. It is also proved that every exhausting Morse function
can be subdivided to yield a locally finite handlebody of the same maximal
index, both in the context of smooth n-manifolds and for Stein surfaces.


title:
eta and eta-prime production in nucleon-nucleon collisions near
  thresholds

abstract:
  The production of eta and eta-prime mesons in nucleon-nucleon collisions near
thresholds is considered within a one-boson exchange model. We show the
feasibility of an experimental access to transition formfactors.


title: Results from Seven Years of AMANDA-II

abstract:
  AMANDA is a first-generation high energy neutrino telescope, which has taken
data at the South Pole in its final configuration since 2000. Results from
seven years of operation are presented here, including observation of the
atmopheric neutrino flux and searches for astrophysical neutrinos from cosmic
ray accelerators, gamma ray bursts, and dark matter annihilations. In 2007,
AMANDA was incorporated into the IceCube neutrino telescope, where its higher
density of instrumentation improves the low energy response. In the near
future, AMANDA will be replaced by the IceCube Deep Core, a purpose-built low
energy extension of IceCube.


title: Detection of the 13CO(J=6-5) Transition in the Starburst Galaxy NGC 253

abstract:
  We report the detection of 13CO(J=6-5) emission from the nucleus of the
starburst galaxy NGC 253 with the redshift (z) and Early Universe Spectrometer
(ZEUS), a new submillimeter grating spectrometer. This is the first
extragalactic detection of the 13CO(J=6-5) transition, which traces warm, dense
molecular gas. We employ a multi-line LVG analysis and find ~ 35% - 60% of the
molecular ISM is both warm (T ~ 110 K) and dense (n(H2) ~ 10^4 cm^-3). We
analyze the potential heat sources, and conclude that UV and X-ray photons are
unlikely to be energetically important. Instead, the molecular gas is most
likely heated by an elevated density of cosmic rays or by the decay of
supersonic turbulence through shocks. If the cosmic rays and turbulence are
created by stellar feedback within the starburst, then our analysis suggests
the starburst may be self-limiting.


title: Quantum Behaviors on an Excreting Black Hole

abstract:
  Often, geometries with horizons offer insights into the intricate
relationships between general relativity and quantum physics. However, some
subtle aspects of gravitating quantum systems might be difficult to ascertain
using static backgrounds, since quantum mechanics incorporates dynamic
measurability constraints (such as the uncertainty principle, etc.).
  For this reason, the behaviors of quantum systems on a dynamic black hole
background are explored in this paper. The velocities and trajectories of
representative outgoing, ingoing, and stationary classical particles are
calculated and contrasted, and the dynamics of simple quantum fields (both
massless and massive) on the space-time are examined. Invariant densities
associated with the quantum fields are exhibited on the Penrose diagram that
represents the excreting black hole.
  Furthermore, a generic approach for the consistent mutual gravitation of
quanta in a manner that reproduces the given geometry is developed. The
dynamics of the mutually gravitating quantum fields are expressed in terms of
the affine parameter that describes local motions of a given quantum type on
the space-time. Algebraic equations that relate the energy-momentum densities
of the quantum fields to Einstein's tensor can then be developed. An example
mutually gravitating system of macroscopically coherent quanta along with a
core gravitating field is demonstrated. Since the approach is generic and
algebraic, it can be used to represent a variety of systems with specified
boundary conditions.


title: A three-parameter neutrino mass matrix with maximal CP violation

abstract:
  Using the seesaw mechanism, we construct a model for the light-neutrino
Majorana mass matrix which yields trimaximal lepton mixing together with
maximal CP violation and maximal atmospheric-neutrino mixing. We demonstrate
that, in our model, the light-neutrino mass matrix retains its form under the
one-loop renormalization-group evolution. With our neutrino mass matrix, the
absolute neutrino mass scale is a function of |U_e3| and of the atmospheric
mass-squared difference. We study the effective mass in neutrinoless double
beta-decay as a function of |U_e3|, showing that it contains a fourfold
ambiguity.


title:
A priori estimates for the motion of a self-gravitating incompressible
  liquid with free surface boundary

abstract:
  In this paper, we prove a priori estimates in Lagrangian coordinates for the
equations of motion of an incompressible, inviscid, self-gravitating fluid with
free boundary. The estimates show that on a finite time interval we control
five derivatives of the fluid velocity and five and a half derivatives of the
coordinates of the moving domain.


title: Generic bounds for Frobenius closure and tight closure

abstract:
  We use geometric and cohomological methods to show that given a degree bound
for membership in ideals of a fixed degree type in the polynomial ring
P=k[x_0,..., x_d], one obtains a good generic degree bound for membership in
the tight closure of an ideal of that degree type in any standard-graded
k-algebra R of dimension d+1. This indicates that the tight closure of an ideal
behaves more uniformly than the ideal itself. Moreover, if R is normal, one
obtains a generic bound for membership in the Frobenius closure. If d is at
most 2, then the bound for ideal membership in P can be computed from the known
cases of the Froeberg conjecture and yields explicit generic tight closure
bounds.


title: Master Space, Hilbert Series and Seiberg Duality

abstract:
  We analyze the action of Toric (Seiberg) duality on the combined mesonic and
baryonic moduli space of quiver gauge theories obtained from D3 branes at
Calabi-Yau singularities. We analyze in particular the structure of the master
space, the complete moduli space for one brane, for different toric phases of a
given singularity. We show that the Hilbert Series for the largest component of
the master space of different phases is the same, when refined with all the non
anomalous charges. This reflects the fact that the quiver gauge theories
associated with different phases are related by Seiberg duality when the number
of branes is greater than one.


title: Detecting the Cosmic Dipole Anisotropy in Large-Scale Radio Surveys

abstract:
  The detection of a dipole anisotropy in the sky distribution of sources in
large-scale radio surveys can be used to constrain the magnitude and direction
of our local motion with respect to an isotropically distributed extragalactic
radio source population. Such a population is predicted to be present at
cosmological redshifts in an isotropically expanding universe. The
extragalactic radio source population is observed to have a median redshift of
z ~ 1, a much later epoch than the cosmic microwave background (z ~ 1100). I
consider the detectability of a velocity dipole anisotropy in radio surveys
having a finite number of source counts. The statistical significance of a
velocity dipole detection from radio source counts is also discussed in detail.
I find that existing large-scale radio survey catalogs do not have a sufficient
number of sources to detect the expected velocity dipole with statistical
significance, even if survey masking and flux calibration complications can be
completely eliminated (i.e., if both the surveys and observing instruments are
perfect). However, a dipole anisotropy should be easily detectable in future
radio surveys planned with next-generation radio facilities, such as the Low
Frequency Array and the Square Kilometer Array; tight constraints on the dipole
magnitude and direction should be possible if flux calibration problems can be
sufficiently minimized or corrected and contamination from local sources
eliminated.


title: Gravitational Radiation by Cosmic Strings in a Junction

abstract:
  The formalism for computing the gravitational power radiation from
excitations on cosmic strings forming a junction is presented and applied to
the simple case of co-planar strings at a junction when the excitations are
generated along one string leg. The effects of polarization of the excitations
and of the back-reaction of the gravitational radiation on the small scale
structure of the strings are studied.


title: Transitive orientations in bull-reducible Berge graphs

abstract:
  A bull is a graph with five vertices $r, y, x, z, s$ and five edges $ry$,
$yx$, $yz$, $xz$, $zs$. A graph $G$ is bull-reducible if no vertex of $G$ lies
in two bulls. We prove that every bull-reducible Berge graph $G$ that contains
no antihole is weakly chordal, or has a homogeneous set, or is transitively
orientable. This yields a fast polynomial time algorithm to color exactly the
vertices of such a graph.


title: Quadratic Binomial APN Functions and Absolutely Irreducible Polynomials

abstract:
  We show that many quadratic binomial functions on a finite field of
characteristic 2 are not APN infinitely often. This is of interest in the light
of recent discoveries of new families of quadratic binomial APN functions. The
proof uses the Weil bound from algebraic geometry.


title: Some new examples with almost positive curvature

abstract:
  As a means to better understanding manifolds with positive curvature, there
has been much recent interest in the study of non-negatively curved manifolds
which contain points at which all 2-planes have positive curvature. We show
that there are generalisations of the well-known Eschenburg spaces and
quotients of $\sph^7 \x \sph^7$ which admit metrics with this property.


title: Fuzzballs and the information paradox: a summary and conjectures

abstract:
  The black hole information paradox is one of the most important issues in
theoretical physics. We review some recent progress using string theory in
understanding the nature of black hole microstates. For all cases where these
microstates have been constructed, one finds that they are horizon sized
`fuzzballs'. Most computations are for extremal states, but recently one has
been able to study a special family of non-extremal microstates, and see
`information carrying radiation' emerge from these gravity solutions. We
discuss how the fuzzball picture can resolve the information paradox. We use
the nature of fuzzball states to make some conjectures on the dynamical aspects
of black holes, observing that the large phase space of fuzzball solutions can
make the black hole more `quantum' than assumed in traditional treatments.


title: Comments on staggered fermions / Panel discussion

abstract:
  The rooting procedure commonly used with staggered fermions does not
correctly treat non-perturbative effects associated with gauge field topology.
In practice these effects are small for the physics of flavor non-singlet
particles. However large uncontrolled systematic errors are expected for flavor
singlet issues, such as the mass of the eta prime meson. While the relative
speed of the algorithm in large scale simulations may justify its use, the
method is an approximation and should not be promoted as a first principles
approach to the strong interactions.


title: Towards Real-time Classification of Astronomical Transients

abstract:
  Exploration of time domain is now a vibrant area of research in astronomy,
driven by the advent of digital synoptic sky surveys. While panoramic surveys
can detect variable or transient events, typically some follow-up observations
are needed; for short-lived phenomena, a rapid response is essential. Ability
to automatically classify and prioritize transient events for follow-up studies
becomes critical as the data rates increase. We have been developing such
methods using the data streams from the Palomar-Quest survey, the Catalina Sky
Survey and others, using the VOEventNet framework. The goal is to automatically
classify transient events, using the new measurements, combined with archival
data (previous and multi-wavelength measurements), and contextual information
(e.g., Galactic or ecliptic latitude, presence of a possible host galaxy
nearby, etc.); and to iterate them dynamically as the follow-up data come in
(e.g., light curves or colors). We have been investigating Bayesian
methodologies for classification, as well as discriminated follow-up to
optimize the use of available resources, including Naive Bayesian approach, and
the non-parametric Gaussian process regression. We will also be deploying
variants of the traditional machine learning techniques such as Neural Nets and
Support Vector Machines on datasets of reliably classified transients as they
build up.


title: Form factors of tetraquarks

abstract:
  The electromagnetic form factors of tetraquarks are calculated in the
framework of relativistic quark model at small and intermediate momentum
transfers Q^2 < 1 GeV^2. The charge radii of X(3872) and X(3940) tetraquarks
are determined.


title: The response of interferometric gravitational wave detectors

abstract:
  The derivation of the response function of an interferometric gravitational
wave detector is a paradigmatic calculation in the field of gravitational wave
detection. Surprisingly, the standard derivation of the response wave detectors
makes several unjustifiable assumptions, both conceptual and quantitative,
regarding the coordinate trajectory and coordinate velocity of the null
geodesic the light travels along. These errors, which appear to have remained
unrecognized for at least 35 years, render the "standard" derivation inadequate
and misleading as an archetype calculation. Here we identify the flaws in the
existing derivation and provide, in full detail, a correct derivation of the
response of a single-bounce Michelson interferometer to gravitational waves,
following a procedure that will always yield correct results; compare it to the
"standard", but incorrect, derivation; show where the earlier mistakes were
made; and identify the general conditions under which the "standard" derivation
will yield correct results. By a fortuitous set of circumstances, not generally
so, the final result is the same in the case of Minkowski background spacetime,
synchronous coordinates, transverse-traceless gauge metric perturbations, and
arm mirrors at coordinate rest.


title: Filiform nilsolitons of dimension 8

abstract:
  A Riemannian manifold (M,g) is said to be Einstein if its Ricci tensor
satisfies ric(g) = cg, for some real number c. In the homogeneous case, a
problem that is still open is the so called Alekseevskii Conjecture. This
conjecture says that any homogeneous Einstein space with negative scalar
curvature (i.e. c < 0) is a solvmanifold: a simply connected solvable Lie group
endowed with a left invariant Riemannian metric. The aim of this paper is to
classify Einstein solvmanifolds of dimension 9 whose nilradicals are 7-step
nilpotent Lie algebras of dimension 8.


title: The loop cohomology of a space with the polynomial cohomology algebra

abstract:
  Given a simply connected space $X$ with the cohomology $H^*(X;{\mathbb Z}_2)$
to be polynomial, we calculate the loop cohomology algebra $H^*(\Omega
X;{\mathbb Z}_2)$ by means of the action of the Steenrod cohomology operation
$Sq_1$ on $H^*(X;{\mathbb Z}_2).$ As a consequence we obtain that $H^*(\Omega
X;{\mathbb Z}_2)$ is the exterior algebra if and only if $Sq_1$ is
multiplicatively decomposable on $H^{\ast}(X;{\mathbb Z}_2).$ The last
statement in fact contains a converse of a theorem of A. Borel.


title:
Perturbative criteria for Anderson localization in long-ranged 1D
  tight-binding models

abstract:
  We develop an alternative scaling approach to determine the criteria for
Anderson localization in one-dimensional tight-binding models with random site
energies having a bandwidth that decays as a power law in space, $H_{ij}
\propto |i - j|^{-\alpha}$. At the first order in perturbation theory the scale
dependence of the exchange-narrowed energy of the disorder is compared to the
energy level spacing of the ideal system to establish whether or not the
disorder has a perturbative effect on the Bloch states. We find that at $\alpha
=1$, the perturbative condition is satisfied and for sufficiently weak disorder
strength all states are extended. For $\alpha > 1$, all states are localized
for arbitrary disorder strength, in agreement with the earlier renormalization
group treatment by Levitov.


title: More on eikonal approximation for high energy scattering

abstract:
  We formulate eikonal approximation to the calculation of high energy
scattering amplitude in the frame where both colliding objects are very
energetic. We express the eikonal scattering matrix in terms of the color
charge densities of the colliding objects. The calculation is performed in the
Hamiltonian formalism. We also show that the appearance of the longitudinal
electric and magnetic fields immediately following the collision is fully taken
into account in the eikonal approximation.


title: Mixing and CP Violation in Decays of Charm Mesons

abstract:
  The phenomenon of mixing in neutral meson systems has now been observed in
all flavours, but only in the past year in the D0 system. The standard model
anticipated that, for the charm sector, the mixing rate would be small, and
also that CP violation, either in mixing or in direct decay, would be below the
present levels of observability. It is hoped that further study of these
phenomena might reveal signs of new physics. A review of recently available,
experimental results is given.


title: Units of ring spectra and Thom spectra

abstract:
  We review and extend the theory of Thom spectra and the associated
obstruction theory for orientations. We recall (from May, Quinn, and Ray) that
a commutative ring spectrum A has a spectrum of units gl(A). To a map of
spectra f: b -> bgl(A), we associate a commutative A-algebra Thom spectrum Mf,
which admits a commutative A-algebra map to R if and only if b -> bgl(A) ->
bgl(R) is null.
  If A is an associative ring spectrum, then to a map of spaces f: B -> BGL(A)
we associate an A-module Thom spectrum Mf, which admits an R-orientation if and
only if B -> BGL(A) -> BGL(R) is null. We also note that BGL(A) classifies the
twists of A-theory.
  We develop and compare two approaches to the theory of Thom spectra. The
first involves a rigidified model of A-infinity and E-infinity spaces. Our
second approach is via infinity categories. In order to compare these
approaches to one another and to the classical theory, we characterize the Thom
spectrum functor from the perspective of Morita theory.


title: Hard Probes of the ATLAS Heavy Ion Physics Program

abstract:
  We review the physics performance of the ATLAS detector for hard probes in
heavy ion collisions, focusing on three topics: jet reconstruction, direct
photon measurement, and heavy flavor jet tagging.


title: Quantum Brownian Motion in a Simple Model System

abstract:
  We consider a quantum particle coupled (with strength $\la$) to a spatial
array of independent non-interacting reservoirs in thermal states (heat baths).
Under the assumption that the reservoir correlations decay exponentially in
time, we prove that the long-time behavior of the particle is diffusive for
small, but finite $\la$. Our proof relies on an expansion around the kinetic
scaling limit ($\la \searrow 0$, while time and space scale as $\la^{-2}$) in
which the particle satisfies a Boltzmann equation. We also show an
equipartition theorem: the distribution of the kinetic energy of the particle
tends to a Maxwell-Boltzmann distribution, up to a correction of $O(\la^2)$.


title: Report of IAU Commission 30 on Radial Velocities (2006-2009)

abstract:
  Brief summaries are given on the following subjects: Radial velocities and
exoplanets (Toward Earth-mass planets; Retired A stars and their planets;
Current status and prospects); Toward higher radial velocity precision; Radial
velocities and asteroseismology; Radial velocities in Galactic and
extragalactic clusters; Radial velocities for field giants; Galactic structure
-- Large surveys (The Geneva-Copenhagen Survey; Sloan Digital Sky Survey;
RAVE); Working groups (WG on radial velocity standards; WG on stellar radial
velocity bibliography; WG on the catalogue of orbital elements of spectroscopic
binaries [SB9]).


title: All-graphene integrated circuits via strain engineering

abstract:
  We propose a route to all-graphene integrated electronic devices by exploring
the influence of strain on the electronic structure of graphene. We show that
strain can be easily tailored to generate electron beam collimation, 1D
channels, surface states and confinement, the basic elements for all-graphene
electronics. In addition this proposal has the advantage that patterning can be
made on substrates rather than on the graphene sheet, thereby protecting the
integrity of the latter.


title: On the Age of the Widest Very Low Mass Binary

abstract:
  We have recently identified the widest very low-mass binary (2M0126AB),
consisting of an M6.5V and an M8V dwarf with a separation of ~5100 AU, which is
twice as large as that of the second widest known system and an order of
magnitude larger than those of all other previously known wide very low-mass
binaries. If this binary belongs to the field population, its constituents
would have masses of ~0.09 Msun, at the lower end of the stellar regime.
However, in the discovery paper we pointed out that its proper motion and
position in the sky are both consistent with being a member of the young (30
Myr) Tucana/Horologium association, raising the possibility that the binary is
a pair of ~0.02 Msun brown dwarfs. We obtained optical spectroscopy at the
Gemini South Observatory in order to constrain the age of the pair and clarify
its nature. The absence of lithium absorption at 671 nm, modest Halpha
emission, and the strength of the gravity-sensitive Na doublet at 818 nm all
point toward an age of at least 200 Myr, ruling out the possibility that the
binary is a member of Tucana/Horologium. We further estimate that the binary is
younger than 2 Gyr based on its expected lifetime in the galactic disk.


title: Argyres-Seiberg duality and the Higgs branch

abstract:
  We demonstrate the agreement between the Higgs branches of two N=2 theories
proposed by Argyres and Seiberg to be S-dual, namely the SU(3) gauge theory
with six quarks, and the SU(2) gauge theory with one pair of quarks coupled to
the superconformal theory with E_6 flavor symmetry. In mathematical terms, we
demonstrate the equivalence between a hyperkaehler quotient of a linear space
and another hyperkaehler quotient involving the minimal nilpotent orbit of E_6,
modulo the identification of the twistor lines.


title: Computing Gorenstein Colength

abstract:
  Given an Artinian local ring $R$, we define its Gorenstein colength $g(R)$ to
measure how closely we can approximate $R$ by a Gorenstein Artin local ring. In
this paper, we show that $R = T/I$ satisfies the inequality $g(R) \leq
\lambda(R/\soc(R))$ in the following two cases: (a) $T$ is a power series ring
over a field of characteristic zero and $I$ an ideal that is the power of a
system of parameters or (b) $T$ is a 2-dimensional regular local ring with
infinite residue field and $I$ is primary to the maximal ideal of $T$.
  In the first case, we compute $g(R)$ by constructing a Gorenstein Artin local
ring mapping onto $R$. We further use this construction to show that an ideal
that is the $n$th power of a system of parameters is directly linked to the
$(n-1)$st power via Gorenstein ideals. A similar method shows that such ideals
are also directly linked to themselves via Gorenstein ideals.
  Keywords: Gorenstein colength; Gorenstein linkage.


title: $Z_7$ Orbifold Models in M-Theory

abstract:
  Among $T^7/\Gamma$ orbifold compactifications of $M$-theory, we examine
models containing the particle physics Standard Model in four-dimensional
spacetimes, which appear as fixed subspaces of the ten-dimensional spacetimes
at each end of the interval, $I^1\simeq S^1/Z_2$, spanning the $11^\text{th}$
dimension. Using the $Z_7$ projection to break the $E_8$ gauge symmetry in each
of the four-planes and a limiting relation to corresponding heterotic string
compactifications, we discuss the restrictions on the possible resulting gauge
field and matter spectra. In particular, some of the states are non-local: they
connect two four-dimensional Worlds across the $11^\text{th}$ dimension.
  We illustrate our programmable calculations of the matter field spectrum,
including the anomalous U(1) factor which satisfies a universal Green-Schwarz
relation, discuss a Dynkin diagram technique to showcase a model with
$SU(3)\times SU(2)\times U(1)^5$ gauge symmetry, and discuss generalizations to
higher order orbifolds.


title: Alternative algebras with the hyperbolic property

abstract:
  We investigate the structure of an alternative finite dimensional
$\Q$-algebra $\mathfrak{A}$ subject to the condition that for a $\Z$-order
$\Gamma \subset \mathfrak{A}$, and thus for every $\Z$-order of $\mathfrak{A}$,
the loop of units of $\U (\Gamma)$ does not contain a free abelian subgroup of
rank two. In particular, we prove that the radical of such an algebra
associates with the whole algebra. We also classify $RA$-loops $L$ for which
$\mathbb{Z}L$ has this property. The classification for group rings is still an
open problem.


title: tbW vertex in the Littlest Higgs Model with T-parity

abstract:
  A study of the effective tbW vertex is done in the littlest Higgs model with
T parity that includes the one loop induced weak dipole coefficient f_{2R}. The
top's width, the W-boson helicity in the t-> bW^+ decay as well as the
t-channel and the s-channel modes of single top quark production at the LHC are
then obtained for the tbW coupling. Our calculation is done in the Feynman-'t
Hooft gauge, and we provide details of the analysis, like exact formulas (to
all orders of the expansion variable v/f) of masses and mixing angles of all
the particles involved. Also, a complete and exact diagonalization (and
normalization) of the scalar sector of the model is made.


title: Spin relaxation in quantum dots due to electron exchange with leads

abstract:
  We calculate spin relaxation rates in lateral quantum dot systems due to
electron exchange between dots and leads. Using rate equations, we develop a
theoretical description of the experimentally observed electric current in the
spin blockade regime of double quantum dots. Single expression fits the entire
current profile and describes the structure of both the conduction peaks and of
the suppressed (`valley') region. Extrinsic rates calculated here have to be
taken into account for accurate extraction of intrinsic relaxation rates due to
the spin-orbit and hyperfine spin scattering mechanisms from spin blockade
measurements.


title: Hierarchies of Biocomplexity: modeling lifes energetic complexity

abstract:
  In this paper, a model for understanding the effects of selection using
systems- level computational approaches is introduced. A number of concepts and
principles essential for understanding the motivation for constructing the
model will be introduced first. This will be followed by a description of
parameters, measurements, and graphical representations used in the model. Four
possible outcomes for this model are then introduced and described. In
addition, the relationship of relative fitness to selection is described.
Finally, the consequences and potential lessons learned from the model are
discussed.


title: N-body Dynamics of Giant Magnons in RxS2

abstract:
  We pursue the question of multi-magnon dynamics, focusing on the simplest
case of magnons moving on RxS2 and working at the semiclassical level. Through
a Pohlmeyer reduction, the problem reduces to another well known integrable
field theory, the sine-Gordon model, which can be exactly described through an
N-body model of Calogero type. The two theories coincide at the level of
equations of motion, but physical quantities like the energies (of magnons and
solitons) and the associated phase shifts are different. We start from the
equivalence of the two systems at the level of equations of motion and require
that the new (string theory) model reproduces the correct magnon energies and
the phase shift, both of which differ from the soliton case. From the
comparison of energies we suggest a Hamiltonian, and from requiring the correct
phase shift we are led to a nontrivial Poisson structure representing the
magnons.


title: Electric polarization in a Chern insulator

abstract:
  We extend the Berry-phase concept of polarization to insulators having a
non-zero value of the Chern invariant. The generalization to such Chern
insulators requires special care because of the partial occupation of chiral
edge states. We show how the integrated bulk current arising from an adiabatic
evolution can be related to a difference of bulk polarizations. We also show
how the surface charge can be related to the bulk polarization, but only with a
knowledge of the wavevector at which the occupancy of the edge state is
discontinuous. Furthermore we present numerical calculations on a model
Hamiltonian to provide additional support for our analytic arguments.


title: Probing embryonic tissue mechanics with laser hole-drilling

abstract:
  We use laser hole-drilling to assess the mechanics of an embryonic epithelium
during development - in vivo and with subcellular resolution. We ablate a
subcellular cylindrical hole clean through the epithelium, and track the
subsequent recoil of adjacent cells (on ms time scales). We investigate dorsal
closure in the fruit fly with emphasis on apical constriction of amnioserosa
cells. The mechanical behavior of this epithelium falls between that of a
continuous sheet and a 2D cellular foam (a network of tensile interfaces).
Tensile stress is carried both by cell-cell interfaces and by the cells' apical
actin networks. Our results show that stress is slightly concentrated along
interfaces (1.6-fold), but only in early closure. Furthermore, closure is
marked by a decrease in the recoil power-law exponent - implying a transition
to a more solid-like tissue. We use the site- and stage-dependence of the
recoil kinetics to constrain how the cellular mechanics change during closure.
We apply these results to test extant computational models.


title: DUSEL Theory White Paper

abstract:
  The NSF has chosen the site for the Deep Underground Science and Engineering
Laboratory (DUSEL) to be in Lead, South Dakota. In fact, the state of South
Dakota has already stepped up to the plate and contributed its own funding for
the proposed lab, see http://www.sanfordlaboratoryathomestake.org/index.html.
The final decision by NSF for funding the Initial Suite of Experiments for
DUSEL will be made early in 2009. At that time the NSF Science Board must make
a decision.
  Of order 200 experimentalists have already expressed an interest in
performing experiments at DUSEL. In order to assess the interest of the
theoretical community, the Center for Cosmology and Astro-Particle Physics
(CCAPP) at The Ohio State University (OSU) organized a 3-day DUSEL Theory
Workshop in Columbus, Ohio from April 4 - 6, 2008. The workshop focused on the
scientific case for six proposed experiments for DUSEL: long baseline neutrino
oscillations, proton decay, dark matter, astrophysical neutrinos, neutrinoless
double beta decay and N-Nbar oscillations.
  The outcome of this workshop is the DUSEL Theory White paper addressing the
scientific case at a level which may be useful in the decision making process
for policy makers at the NSF and in the U.S. Congress. In order to assess the
physics interest in the DUSEL project we have posted the DUSEL Theory White
paper on the following CCAPP link http://ccapp.osu.edu/whitepaper.html . Please
read the white paper and, if you are interested, use the link to show your
support by co-signing the white paper.


title: Non-thermal Electrons at the Earth's Bow Shock: A `Gradual' Event

abstract:
  Earth's bow shock is known to produce non-thermal electrons which are
generally observed as a `spike' in their flux profile. Here, in this paper, we
present an analysis of electron and whistler wave properties for a
quasi-perpendicular shock crossing that is supercritical, but subcritical to
the so-called whistler critical Mach number, M$^w_{\rm crit}$, above which
whistler waves cannot propagate upstream. We have found that the amplitudes of
whistler waves increased exponentially as a function of time prior to the shock
encounter, while the suprathermal ($>$ 2 keV) electron flux similarly increased
with time, although with differing $e$-folding time scales. Comparison of the
electron energy spectrum measured within the ramp with predictions from
diffusive shock acceleration theory was poor, but the variation of pitch angle
distribution showed scattering of non-thermal electrons in the upstream region.
While not finding a specific mechanism to account for the electron diffusion,
we suggest that the whistlers seen probably account for the differences
observed between this `gradual' event and the `spike' events seen at shocks
with no upstream whistlers.


title: Online Coordinate Boosting

abstract:
  We present a new online boosting algorithm for adapting the weights of a
boosted classifier, which yields a closer approximation to Freund and
Schapire's AdaBoost algorithm than previous online boosting algorithms. We also
contribute a new way of deriving the online algorithm that ties together
previous online boosting work. We assume that the weak hypotheses were selected
beforehand, and only their weights are updated during online boosting. The
update rule is derived by minimizing AdaBoost's loss when viewed in an
incremental form. The equations show that optimization is computationally
expensive. However, a fast online approximation is possible. We compare
approximation error to batch AdaBoost on synthetic datasets and generalization
error on face datasets and the MNIST dataset.


title:
Low-temperature behavior of the Abelian Higgs model in anti-de Sitter
  space

abstract:
  We explore the low-temperature behavior of the Abelian Higgs model in AdS_4,
away from the probe limit in which back-reaction of matter fields on the metric
can be neglected. Over a significant range of charges for the complex scalar,
we observe a second order phase transition at finite temperature. The
symmetry-breaking states are superconducting black holes. At least when the
charge of the scalar is not too small, we observe at low temperatures the
emergence of a domain wall structure characterized by a definite index of
refraction. We also compute the conductivity as a function of frequency.


title: Wave refraction in left-handed materials

abstract:
  We examine the response of a plane wave incident on a flat surface of a
medium characterized by simultaneously negative electric and magnetic
susceptibilities by solving Maxwell's equations explicitly and without making
any assumptions on the way. In the literature up to date, it has been assumed
that negative refractive materials are necessarily frequency dispersive. We
propose an alternative to this assumption by suggesting that the requirement of
positive energy density should be relaxed, and discuss the implications of such
a proposal. More specifically, we show that once negative energy solutions are
accepted, the necessity for frequency dispersion is no longer necessary.
Finally, we argue that, for the purposes of discussing negative index
materials, the use of group velocity as the physically significant quantity is
misleading, and suggest that any discussion involving it should be carefully
reconsidered.


title:
Sakurai's Object: characterising the near-infrared CO ejecta between
  2003 and 2007

abstract:
  We present observations of Sakurai's Object obtained at 1-5um between 2003
and 2007. By fitting a radiative transfer model to an echelle spectrum of CO
fundamental absorption features around 4.7um, we determine the excitation
conditions in the line-forming region. We find 12C/13C~3.5, consistent with CO
originating in ejecta processed by the very late thermal pulse, rather than in
the pre-existing planetary nebula. We demonstrate the existence of
2.2e-6<M<2.7e-6 Msun of CO ejecta outside the dust, forming a high-velocity
wind of 500+/-80 km/s. We find evidence for significant weakening of the CO
band and cooling of the dust around the central star between 2003 and 2005. The
gas and dust temperatures are implausibly high for stellar radiation to be the
sole contributor.


title: Baryon Spectroscopy from Lattice QCD

abstract:
  Progress in extracting excited-state baryon masses in lattice QCD using large
sets of spatially-extended operators is presented. The use of stochastic
estimates of all-to-all quark propagators with variance reduction techniques is
described. Such techniques are crucial for incorporating multi-hadron operators
into the correlation matrices of the hadron operators.


title: The $J$-matrix method

abstract:
  Given an operator L acting on a function space, the J-matrix method consists
of finding a sequence y_n of functions such that the operator L acts
tridiagonally on y_n with respect to n. Once such a tridiagonalization is
obtained, a number of characteristics of such an operator L can be obtained. In
particular, information on eigenvalues and eigenfunctions, bound states,
spectral decompositions, etc. can be obtained in this way. We review the
general set-up, and we discuss two examples in detail; the Schrodinger operator
with Morse potential and the Lame equation.


title: Waveguide-based single-pixel up-conversion infrared spectrometer

abstract:
  A periodically poled lithium niobate (PPLN) waveguide-based single-pixel
up-conversion infrared spectrometer was demonstrated. Sum-frequency generation
between a 1.5 micrometer band scanning pump laser and a 1.3 micrometer band
signal generated visible radiation which was detected by a silicon
single-photon detector. The noise equivalent power of the upconversion
spectrometer was two-orders-of-magnitude lower than that of a commercial
optical spectrum analyzer.


title:
Interplay between interaction and (un)correlated disorder in
  one-dimensional many-particle systems: delocalization and global entanglement

abstract:
  We consider a one-dimensional quantum many-body system and investigate how
the interplay between interaction and on-site disorder affects spatial
localization and quantum correlations. The hopping amplitude is kept constant.
To measure localization, we use the number of principal components (NPC), which
quantifies the spreading of the system eigenstates over vectors of a given
basis set. Quantum correlations are determined by a global entanglement measure
$Q$, which quantifies the degree of entanglement of multipartite pure states.
Our studies apply analogously to a one-dimensional system of interacting
spinless fermions, hard-core bosons, or yet to an XXZ Heisenberg spin-1/2
chain. Disorder is characterized by both: uncorrelated and long-range
correlated random on-site energies. Dilute and half-filled chains are analyzed.
In half-filled clean chains, delocalization is maximum when the particles do
not interact, whereas multi-partite entanglement is largest when they do. In
the presence of uncorrelated disorder, NPC and Q show a non-trivial behavior
with interaction, peaking in the chaotic region. The inclusion of correlated
disorder may further extend two-particle states, but the effect decreases with
the number of particles and strength of their interactions. In half-filled
chains with large interaction, correlated disorder may even enhance
localization.


title:
Observational $5-20\mu$m Interstellar Extinction Curves Toward
  Star-Forming Regions Derived from Spitzer IRS Spectra

abstract:
  Using \emph{Spitzer} Infrared Spectrograph observations of G0--M4 III stars
behind dark clouds, I construct $5-20\mu$m empirical extinction curves for
$0.3\leq A_K<7$, which is equivalent to $A_V$ between $\approx$ 3 and 50. For
$A_K<1$ the curve appears similar to the \citet{mathis90} diffuse interstellar
medium extinction curve, but with a greater degree of extinction. For $A_K>1$,
the curve exhibits lower contrast between the silicate and absorption
continuum, developes ice absorption, and lies closer to the \citet{wd01}
$R_V=5.5$ case B curve, a result which is consistent with that of
\citet{flaherty07} and \citet{chiar07}. Recently work using \emph{Spitzer}
Infrared Array Camera data by \citet{chapman08} independently reaches a similar
conclusion, that the shape of the extinction curve changes as a function of
increasing $A_K$. By calculating the optical depths of the $9.7\mu$m silicate
and 6.0, 6.8, and 15.2 $\mu$m ice features, I determine that a process
involving ice is responsible for the changing shape of the extinction curve and
speculate that this process is coagulation of ice-mantled grains rather than
ice-mantled grains alone.


title: Manifolds of semi-negative curvature

abstract:
  The notion of nonpositive curvature in Alexandrov's sense is extended to
include p-uniformly convex Banach spaces. Infinite dimensional manifolds of
semi-negative curvature with a p-uniformly convex tangent norm fall in this
class on nonpositively curved spaces, and several well-known results, such as
existence and uniqueness of best approximations from convex closed sets, or the
Bruhat-Tits fixed point theorem, are shown to hold in this setting, without
dimension restrictions. Homogeneous spaces G/K of Banach-Lie groups of
semi-negative curvature are also studied, explicit estimates on the geodesic
distance and sectional curvature are obtained. A characterization of convex
homogeneous submanifolds is given in terms of the Banach-Lie algebras. A
splitting theorem via convex expansive submanifolds is proven, inducing the
corresponding splitting of the Banach-Lie group G. Finally, these notions are
used to study the structure of the classical Banach-Lie groups of bounded
linear operators acting on a Hilbert space, and the splittings induced by
conditional expectations in such setting.


title:
Measurement of the Partial Cross Sections s(TT), s(LT) and
  [s(T)+epsilon*s(L)] of the p(e,e' pi+)n Reaction in the Delta(1232) Resonance

abstract:
  We report new precision p(e,e' pi+})n measurements in the Delta(1232)
resonance at Q2 = 0.127(GeV/c)2 obtained at the MIT-Bates Out-Of-Plane
scattering facility. These are the lowest, but non-zero, Q2 measurements in the
pi+ channel. The data offer new tests of the theoretical calculations,
particularly of the background amplitude contributions. The chiral effective
field theory and Sato-Lee model calculations are not in agreement with this
experiment.


title:
Epsilon Eridani's Planetary Debris Disk: Structure and Dynamics based on
  Spitzer and CSO Observations

abstract:
  Spitzer and Caltech Submillimeter Observatory (CSO) images and
spectrophotometry of epsilon Eridani at wavelengths from 3.5 to 350 um reveal
new details of its bright debris disk. The 350 um map confirms the presence of
a ring at r = 11-28 arcsec (35-90 AU) observed previously at longer sub-mm
wavelengths. The Spitzer mid- and far-IR images do not show the ring, but
rather a featureless disk extending from within a few arcsec of the star across
the ring to r ~ 34 arcsec (110 AU). The spectral energy distribution (SED) of
the debris system implies a complex structure. A model constrained by the
surface brightness profiles and the SED indicates that the sub-mm ring emission
is primarily from large (a ~ 135 um) grains, with smaller (a ~ 15 um) grains
also present in and beyond the ring. The Spitzer IRS and MIPS SED-mode
spectrophotometry data clearly show the presence of spatially compact excess
emission at lambda > 15 um that requires the presence of two additional narrow
belts of dust within the sub-mm ring's central void. The innermost belt at r ~
3 AU is composed of silicate dust. A simple dynamical model suggests that dust
produced collisionally by a population of about 11 M_Earth of planetesimals in
the sub-mm ring could be the source of the emission from both in and beyond the
sub-mm ring. Maintaining the inner belts and the inner edge to the sub-mm ring
may require the presence of three planets in this system including the
candidate radial velocity object.


title: Non-linear Study of Bell's Cosmic Ray Current-driven Instability

abstract:
  The cosmic ray current-driven (CRCD) instability, predicted by Bell (2004),
consists of non-resonant, growing plasma waves driven by the electric current
of cosmic rays (CRs) that stream along the magnetic field ahead of both
relativistic and non-relativistic shocks. Combining an analytic, kinetic model
with one-, two-, and three-dimensional particle-in-cell simulations, we confirm
the existence of this instability in the kinetic regime and determine its
saturation mechanisms. In the linear regime, we show that, if the background
plasma is well magnetized, the CRCD waves grow exponentially at the rates and
wavelengths predicted by the analytic dispersion relation. The magnetization
condition implies that the growth rate of the instability is much smaller than
the ion cyclotron frequency. As the instability becomes non-linear, significant
turbulence forms in the plasma. This turbulence reduces the growth rate of the
field and damps the shortest wavelength modes, making the dominant wavelength,
\lambda_d, grow proportional to the square of the field. At constant CR
current, we find that plasma acceleration along the motion of CRs saturates the
instability at the magnetic field level such that v_A ~ v_{d,cr}, where v_A is
the Alfven velocity in the amplified field, and v_{d,cr} is the drift velocity
of CRs. The instability can also saturate earlier if CRs get strongly deflected
by the amplified field, which happens when their Larmor radii get close to
\lambda_d. We apply these results to the case of CRs in the upstream medium of
supernova remnants. Considering only the most energetic CRs that escape from
the shock, we obtain that the field amplification factor of ~10 can be reached.
This confirms the CRCD instability as a potentially important component of
magnetic amplification process in astrophysical shocks.


title: Forward and midrapidity charmonium production at RHIC

abstract:
  $J/\psi$ production at forward and midrapidity at the Relativistic Heavy-Ion
Collider (RHIC) is calculated within a previously constructed rate-equation
approach accounting for both direct production and regeneration from $c$ and
$\bar c$. The results are compared to experimental data. The observed stronger
suppression at forward rapidity can be qualitatively explained by a smaller
statistical regeneration component together with stronger cold nuclear matter
induced suppression compared to midrapidity. The $\chi_c$ over $J/\psi$ ratio
and $\psi'$ over $J/\psi$ ratio are also calculated.


title: Simplicity of finitely-aligned k-graph C*-algebras

abstract:
  It is shown that no local periodicity is equivalent to the aperiodicity
condition for arbitrary finitely-aligned k-graphs. This allows us to conclude
that C*(\Lambda) is simple if and only if \Lambda is cofinal and has no local
periodicity.