title: Inverse Limits of Uniform Covering Maps

abstract:
  In ``Rips complexes and covers in the uniform category'' the authors define,
following James, covering maps of uniform spaces and introduce the concept of
generalized uniform covering maps. Conditions for the existence of universal
uniform covering maps and generalized uniform covering maps are given. This
paper notes that the universal generalized uniform covering map is uniformly
equivalent to the inverse limit of uniform covering maps and is therefore
approximated by uniform covering maps. A characterization of generalized
uniform covering maps that are approximated by uniform covering maps is
provided as well as a characterization of generalized uniform covering maps
that are uniformly equivalent to the inverse limit of uniform covering maps.
Inverse limits of group actions that induce generalized uniform covering maps
are also treated.


title: Magnetocapacitance of a graphene monolayer

abstract:
  We present a theoretical study of magnetocapacitance in a graphene monolayer
at finite temperature taking into account the effects of disorder. The density
of states (DOS) and magnetocapacitance found for graphene are compared to those
found in standard two dimensional electron gas (2DEG) systems. The magnetic
oscillations in DOS and magnetocapacitance are found to be enhanced and much
more robust with respect to temperature damping in monolayer graphene in
comparison with a 2DEG. Furthermore, we find that there is a $\pi$ phase shift
between magnetic oscillations in the two systems which can be attributed to
Dirac electrons in graphene acquiring a Berry's phase as they traverse a closed
path in a magnetic field.


title:
On the Anomalous Silicate Emission Features of AGNs: A Possible
  Interpretation Based on Porous Dust

abstract:
  The recent Spitzer detections of the 9.7 micron Si--O silicate emission in
type 1 AGNs provide support for the AGN unification scheme. The properties of
the silicate dust are of key importance to understanding the physical, chemical
and evolutionary properties of the obscuring dusty torus around AGNs. Compared
to that of the Galactic interstellar medium (ISM), the 10 micron silicate
emission profile of type 1 AGNs is broadened and has a clear shift of peak
position to longer wavelengths. In literature this is generally interpreted as
an indication of the deviations of the silicate composition, size, and degree
of crystallization of AGNs from that of the Galactic ISM. In this Letter we
show that the observed peak shift and profile broadening of the 9.7 micron
silicate emission feature can be explained in terms of porous composite dust
consisting of ordinary interstellar amorphous silicate, amorphous carbon and
vacuum. Porous dust is naturally expected in the dense circumnuclear region
around AGNs, as a consequence of grain coagulation.


title: Swapping Lemmas for Regular and Context-Free Languages

abstract:
  In formal language theory, one of the most fundamental tools, known as
pumping lemmas, is extremely useful for regular and context-free languages.
However, there are natural properties for which the pumping lemmas are of
little use. One of such examples concerns a notion of advice, which depends
only on the size of an underlying input. A standard pumping lemma encounters
difficulty in proving that a given language is not regular in the presence of
advice. We develop its substitution, called a swapping lemma for regular
languages, to demonstrate the non-regularity of a target language with advice.
For context-free languages, we also present a similar form of swapping lemma,
which serves as a technical tool to show that certain languages are not
context-free with advice.


title: Optical Properties of Dust

abstract:
  Except in a few cases cosmic dust can be studied in situ or in terrestrial
laboratories, essentially all of our information concerning the nature of
cosmic dust depends upon its interaction with electromagnetic radiation. This
chapter presents the theoretical basis for describing the optical properties of
dust -- how it absorbs and scatters starlight and reradiates the absorbed
energy at longer wavelengths.


title:
Recent PHENIX Results on pi+, pi-, and eta Production in polarized pp
  Collisions at RHIC at sqrt(s) = 200 GeV

abstract:
  Measurements of double helicity asymmetries for inclusive hadron production
in polarized proton-proton collisions are sensitive to spin-dependent parton
distribution functions, in particular to the gluon distribution function. This
study focuses on double helicity asymmetries in eta and charged pion production
at mid-rapidity, as well as on the eta cross section and fragmentation
functions.


abstract:
  We define the Poisson quasi-Nijenhuis structures with background on Lie
algebroids and we prove that to any generalized complex structure on a Courant
algebroid which is the double of a Lie algebroid is associated such a
structure. We prove that any Lie algebroid with a Poisson quasi-Nijenhuis
structure with background constitutes, with its dual, a quasi-Lie bialgebroid.
We also prove that any pair $(\pi,\omega)$ of a Poisson bivector and a 2-form
induces a Poisson quasi-Nijenhuis structure with background and we observe that
particular cases correspond to already known compatibilities between $\pi$ and
$\omega$.


title: On Buckyonions as an Interstellar Grain Component

abstract:
  The carrier of the 2175 Angstrom interstellar extinction feature remains
unidentified since its first detection over 40 years ago. In recent years
carbon buckyonions have been proposed as a carrier of this feature, based on
the close similarity between the electronic transition spectra of buckyonions
and the 2175 Angstrom interstellar feature. We examine this hypothesis by
modeling the interstellar extinction with buckyonions as a dust component. It
is found that dust models containing buckyonions (in addition to amorphous
silicates, polycyclic aromatic hydrocarbon molecules, graphite) can closely
reproduce the observed interstellar extinction curve. To further test this
hypothesis, we call for experimental measurements and/or theoretical
calculations of the infrared vibrational spectra of hydrogenated buckyonions.
By comparing the infrared emission spectra predicted for buckyonions
vibrationally excited by the interstellar radiation with the observed emission
spectra of the diffuse interstellar medium, we will be able to derive (or place
an upper limit on) the abundance of interstellar buckyonions.


title: Spectral action and neutrino mass

abstract:
  We propose the extension of the spectral action principle to fermions and
show that the neutrino mass terms appear then naturally as next-order
corrections.


title:
Predictions for Supersymmetric Particle Masses in the CMSSM using
  Indirect Experimental and Cosmological Constraints

abstract:
  In view of the imminent start of the LHC experimental programme, we use the
available indirect experimental and cosmological information to estimate the
likely range of parameters of the constrained minimal supersymmetric extension
of the Standard Model (CMSSM), using a Markov-chain Monte Carlo (MCMC)
technique to sample the parameter space. The 95% confidence-level area in the
(m_0, m_1/2) plane of the CMSSM lies largely within the region that could be
explored with 1/fb of integrated luminosity at 14 TeV, and much of the 68%
confidence-level area lies within the region that could be explored with 50/pb
of integrated luminosity at 10 TeV. A same-sign dilepton signal could well be
visible in most of the 68% confidence-level area with 1/fb of integrated
luminosity at 14 TeV. We discuss the sensitivities of the preferred ranges to
variations in the most relevant indirect experimental and cosmological
constraints and also to deviations from the universality of the
supersymmetry-breaking contributions to the masses of the Higgs bosons.


title: On the Crystallinity of Silicate Dust in the Interstellar Medium

abstract:
  An accurate knowledge of the mineralogy (chemical composition and crystal
structure) of the silicate dust in the interstellar medium (ISM) is crucial for
understanding its origin in evolved stars, the physical and chemical processing
in the ISM, and its subsequent incorporation into protostellar nebulae,
protoplanetary disks and cometary nuclei where it is subjected to further
processing. While an appreciable fraction of silicate dust in evolved stars, in
protoplanetary disks around pre-main sequence stars, in debris disks around
main sequence stars, and in cometary nuclei is found to be in crystalline form,
very recent infrared spectroscopic studies of the dust along the sightline
toward the Galactic center source Sgr A* placed an upper limit of ~1.1% on the
silicate crystalline fraction, well below the previous estimates of ~5% or ~60%
derived from the observed 10 micron absorption profile for the local ISM toward
Cyg OB2 No.12. Since the sightline toward SgrA contains molecular cloud
materials as revealed by the detection of the 3.1 and 6.0 micron water ice
absorption features, we argue that by taking into account the presence of ice
mantles on silicate cores, the upper limit on the degree of silicate
crystallinity in the ISM is increased to ~3--5%.


title: Tentative Detection of the Rotation of Eris

abstract:
  We report a multi-week sequence of B-band photometric measurements of the
dwarf planet Eris using the {\it Swift} satellite. The use of an observatory in
low-Earth orbit provides better temporal sampling than is available with a
ground-based telescope. We find no compelling evidence for an unusually slow
rotation period of multiple days, as has been suggested previously. A
$\sim$1.08 day rotation period is marginally detected at a modest level of
statistical confidence ($\sim$97%). Analysis of the combination of the $Swift$
data with the ground-based B-band measurements of \citet{2007AJ....133...26R}
returns the same period ($\sim$1.08 day) at a slightly higher statistical
confidence ($\sim$99%).


title: Acoustooptic Bragg Diffraction in 2-Dimensional Photonic Crystals

abstract:
  The paper shows that silicon-based 2D photonic crystal can be a promising
material for acoustooptical devices. Isotropic and anisotropic Bragg
diffraction of light in photonic crystal is considered. The computational
method for calculation of frequency dependences of Bragg angle is developed. A
simple method of optimization of photonic crystal parameters to obtain Bragg
diffraction at necessary light and sound frequency is suggested.


title:
Prediction for the He I 10830A Absorption Wing in the Coming Event of
  Eta Carinae

abstract:
  We propose an explanation to the puzzling appearance of a wide blue
absorption wing in the He I 10830A P-Cygni profile of the massive binary star
Eta Carinae several months before periastron passage. Our basic assumption is
that the colliding winds region is responsible for the blue wing absorption. By
fitting observations, we find that the maximum outflow velocity of this
absorbing material is ~2300 km/s. We also assume that the secondary star is
toward the observer at periastron passage. With a toy-model we achieve two
significant results. (1) We show that the semimajor axis orientation we use can
account for the appearance and evolution of the wide blue wing under our basic
assumption. (2) We predict that the Doppler shift (the edge of the absorption
profile) will reach a maximum 0-3 weeks before periastron passage, and not
necessarily exactly at periastron passage or after periastron passage.


title:
Tableau-based decision procedure for the multi-agent epistemic logic
  with operators of common and distributed knowledge

abstract:
  We develop an incremental-tableau-based decision procedure for the
multi-agent epistemic logic MAEL(CD) (aka S5_n (CD)), whose language contains
operators of individual knowledge for a finite set Ag of agents, as well as
operators of distributed and common knowledge among all agents in Ag. Our
tableau procedure works in (deterministic) exponential time, thus establishing
an upper bound for MAEL(CD)-satisfiability that matches the (implicit)
lower-bound known from earlier results, which implies ExpTime-completeness of
MAEL(CD)-satisfiability. Therefore, our procedure provides a complexity-optimal
algorithm for checking MAEL(CD)-satisfiability, which, however, in most cases
is much more efficient. We prove soundness and completeness of the procedure,
and illustrate it with an example.


title: Spectral Sparsification of Graphs

abstract:
  We introduce a new notion of graph sparsificaiton based on spectral
similarity of graph Laplacians: spectral sparsification requires that the
Laplacian quadratic form of the sparsifier approximate that of the original.
This is equivalent to saying that the Laplacian of the sparsifier is a good
preconditioner for the Laplacian of the original. We prove that every graph has
a spectral sparsifier of nearly linear size. Moreover, we present an algorithm
that produces spectral sparsifiers in time $\softO{m}$, where $m$ is the number
of edges in the original graph. This construction is a key component of a
nearly-linear time algorithm for solving linear equations in
diagonally-dominant matrcies. Our sparsification algorithm makes use of a
nearly-linear time algorithm for graph partitioning that satisfies a strong
guarantee: if the partition it outputs is very unbalanced, then the larger part
is contained in a subgraph of high conductance.


title:
Achieving the Empirical Capacity Using Feedback Part I: Memoryless
  Additive Models

abstract:
  We address the problem of universal communications over an unknown channel
with an instantaneous noiseless feedback, and show how rates corresponding to
the empirical behavior of the channel can be attained, although no rate can be
guaranteed in advance. First, we consider a discrete modulo-additive channel
with alphabet $\mathcal{X}$, where the noise sequence $Z^n$ is arbitrary and
unknown and may causally depend on the transmitted and received sequences and
on the encoder's message, possibly in an adversarial fashion. Although the
classical capacity of this channel is zero, we show that rates approaching the
empirical capacity $\log|\mathcal{X}|-H_{emp}(Z^n)$ can be universally
attained, where $H_{emp}(Z^n)$ is the empirical entropy of $Z^n$. For the more
general setting where the channel can map its input to an output in an
arbitrary unknown fashion subject only to causality, we model the empirical
channel actions as the modulo-addition of a realized noise sequence, and show
that the same result applies if common randomness is available. The results are
proved constructively, by providing a simple sequential transmission scheme
approaching the empirical capacity. In part II of this work we demonstrate how
even higher rates can be attained by using more elaborate models for channel
actions, and by utilizing possible empirical dependencies in its behavior.


title:
Equation-of-State Dependent Features in Shock-Oscillation Modulated
  Neutrino and Gravitational-Wave Signals from Supernovae

abstract:
  We present 2D hydrodynamic simulations of the long-time accretion phase of a
15 solar mass star after core bounce and before the launch of a supernova
explosion. Our simulations are performed with the Prometheus-Vertex code,
employing multi-flavor, energy-dependent neutrino transport and an effective
relativistic gravitational potential. Testing the influence of a stiff and a
soft equation of state for hot neutron star matter, we find that the non-radial
mass motions in the supernova core due to the standing accretion shock
instability (SASI) and convection impose a time variability on the neutrino and
gravitational-wave signals. These variations have larger amplitudes as well as
higher frequencies in the case of a more compact nascent neutron star. After
the prompt shock-breakout burst of electron neutrinos, a more compact accreting
remnant radiates neutrinos with higher luminosities and larger mean energies.
The observable neutrino emission in the direction of SASI shock oscillations
exhibits a modulation of several 10% in the luminosities and ~1 MeV in the mean
energies with most power at typical SASI frequencies of 20-100 Hz. At times
later than 50-100 ms after bounce the gravitational-wave amplitude is dominated
by the growing low-frequency (<200 Hz) signal associated with anisotropic
neutrino emission. A high-frequency wave signal is caused by nonradial gas
flows in the outer neutron star layers, which are stirred by anisotropic
accretion from the SASI and convective regions. The gravitational-wave power
then peaks at about 300-800 Hz with distinctively higher spectral frequencies
originating from the more compact and more rapidly contracting neutron star.
The detectability of the SASI effects in the neutrino and gravitational-wave
signals is briefly discussed. (abridged)


title: Effect of Induced Spin-Orbit Coupling for Atoms via Laser Fields

abstract:
  We propose an experimental scheme to study spin-orbit coupling effects in a
of two-dimensional (2D) Fermi atomic gas cloud by coupling its internal
electronic states (pseudospins) to radiation in a delta configuration. The
induced spin-orbit coupling can be of the Dresselhaus and Rashba type with and
without a Zeeman term. We show that the optically induced spin-orbit coupling
can lead to a spin-dependent effective mass under appropriate condition, with
one of them able to be tuned between positive and negative effective mass. As a
direct observable we show that in the expansion dynamics of the atomic cloud
the initial atomic cloud splits into two clouds for the positive effective mass
case regime, and into four clouds for the negative effective mass regime.


title: Bianchi-B\"{a}cklund transforms and dressing actions, revisited

abstract:
  We characterize Bianchi-B\"{a}cklund transformations of surfaces of positive
constant Gauss curvature in terms of dressing actions of the simplest type on
the space of harmonic maps.


title:
Transversity and Transverse-Momentum-Dependent Distribution Measurements
  from PHENIX and BRAHMS

abstract:
  A variety of measurements performed utilizing transversely polarized proton-
proton collisions at the Relativistic Heavy Ion Collider (RHIC) are now avail-
able. Recent results from the PHENIX and BRAHMS experiments are presented and
discussed.


title: Fidelity approach to the disordered quantum XY model

abstract:
  We study the random XY spin chain in a transverse field by analyzing the
susceptibility of the ground state fidelity, numerically evaluated through a
standard mapping of the model onto quasi-free fermions. It is found that the
fidelity susceptibility and its scaling properties provide useful information
about the phase diagram. In particular it is possible to determine the Ising
critical line and the Griffiths phase regions, in agreement with previous
analytical and numerical results.


title:
General Relativistic Hydrodynamic Simulations and Linear Analysis of the
  Standing Accretion Shock Instability around a Black Hole

abstract:
  We study the stability of standing shock waves in advection-dominated
accretion flows into a Schwarzschild black hole by 2D general relativistic
hydrodynamic simulations as well as linear analysis in the equatorial plane. We
demonstrate that the accretion shock is stable against axisymmetric
perturbations but becomes unstable to non-axisymmetric perturbations. The
results of dynamical simulations show good agreement with linear analysis on
the stability, oscillation and growing time scales. The comparison of different
wave-travel times with the growth time scales of the instability suggests that
the instability is likely to be of the Papaloizou-Pringle type, induced by the
repeated propagations of acoustic waves. However, the wavelengths of
perturbations are too long to clearly define the reflection point. By analyzing
the non-linear phase in the dynamical simulations, it is shown that quadratic
mode couplings precede the non-linear saturation. It is also found that not
only short-term random fluctuations by turbulent motions but also quasi
periodic oscillations take place on longer time scales in the non-linear phase.
We give some possible implications of the instability for quasi periodic
oscillations (QPOs) and the central engine for gamma ray bursts (GRBs).


title: Observation of the doubly strange b baryon Omega_b-

abstract:
  We report the observation of the doubly strange b baryon Omega_b- in the
decay channel Omega_b- to J/psi Omega-, with J/psi to mu+ mu- and Omega- to
Lambda K-, in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV. Using approximately
1.3 fb$^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron
Collider, we observe 17.8 +/- 4.9 (stat) +/- 0.8 (syst) Omega_b- signal events
at a mass of 6.165 +/- 0.010 (stat) +/- 0.013(syst.) GeV. The significance of
the observed signal is 5.4 sigma, corresponding to a probability of 6.7 x
10^{-8} of it arising from a background fluctuation.


title: Adiabaticity and localization in one-dimensional incommensurate lattices

abstract:
  We experimentally investigate the role of localization on the adiabaticity of
loading a Bose-Einstein condensate into a one-dimensional optical potential
comprised of a shallow primary lattice plus one or two perturbing lattice(s) of
incommensurate period. We find that even a very weak perturbation causes
dramatic changes in the momentum distribution and makes adiabatic loading of
the combined lattice much more difficult than for a single period lattice. We
interpret our results using a band structure model and the one-dimensional
Gross-Pitaevskii equation.


title: Asymptotic and descent formulas for weighted orbital integrals

abstract:
  We rewrite Arthur's asymptotic formula for weighted orbital integrals on real
groups with the aid of a residue calculus and extend the resulting formula to
the Schwartz space. Then we extract the available information about the
coefficients in the decomposition of the Fourier transforms of Arthur's
invariant distributions I_M(\gamma) in terms of standard solutions of the
pertinent holonomic system of differential equations. This allows us to
determine some of those coefficients explicitly. Finally, we prove descent
formulas for those differential equations, for their standard solutions and for
the aforementioned coefficients, which reduce each of them to the case that
\gamma is elliptic in M.


title:
Resistance Fluctuations in Composite Fermion State near Landau Level
  Filling Factor $\nu= 1/2$ in A Square Quantum Well

abstract:
  We have studied the magnetotransport near Landau level filling factor $\nu =
1/2$ in a GaAs-Al0.3Ga0.7As square quantum well (width 35 nm) in magnetic field
up to 42 T and in a temperature range between 50 mK and 1.5 K. In low
temperatures T < 200 mK, the Rxx exhibits a deep, strongly
temperature-dependent minimum centered at $\nu = 1/2$. The concomitant Rxy is
not strictly linear with magnetic field (B) and the first derivative of Rxy
with respect to B shows a sharp cusp at $\nu = 1/2$, indicating a non-classical
Hall effect. We verify these characteristics are being single-layer origin by
applying an in-plane magnetic field or electrostatic gates. The data may signal
frustrations in the composite fermion state towards $\nu = 1/2$ pairing in the
quantum well where the electron layer thickness far exceeds the magnetic
length.


title: Dynamic Connectivity in ALOHA Ad Hoc Networks

abstract:
  In a wireless network the set of transmitting nodes changes frequently
because of the MAC scheduler and the traffic load. Previously, connectivity in
wireless networks was analyzed using static geometric graphs, and as we show
leads to an overly constrained design criterion. The dynamic nature of the
transmitting set introduces additional randomness in a wireless system that
improves the connectivity, and this additional randomness is not captured by a
static connectivity graph. In this paper, we consider an ad hoc network with
half-duplex radios that uses multihop routing and slotted ALOHA for the MAC
contention and introduce a random dynamic multi-digraph to model its
connectivity. We first provide analytical results about the degree distribution
of the graph. Next, defining the path formation time as the minimum time
required for a causal path to form between the source and destination on the
dynamic graph, we derive the distributional properties of the connection delay
using techniques from first-passage percolation and epidemic processes. We
consider the giant component of the network formed when communication is
noise-limited (by neglecting interference). Then, in the presence of
interference, we prove that the delay scales linearly with the
source-destination distance on this giant component. We also provide simulation
results to support the theoretical results.


title: Heteronuclear quantum gas mixtures

abstract:
  This PhD tutorial article is a review of our experiments on heteronuclear
quantum gas mixtures at the University of Hamburg. We introduce basic
properties of trapped Fermi-Bose mixtures and demonstrate the achievement of
large quantum degenerate mixtures of 40K and 87Rb. Using heteronuclear Feshbach
resonances, we show how the heteronuclear interaction can be tuned, allowing us
to induce phase separation and collapse for large repulsive and attractive
interactions, respectively. We realize Fermi-Bose mixtures in 3D optical
lattices as a novel quantum many-body system and study coherence properties of
the mixture. Combining our experiments on lattices and Feshbach resonances, we
present the first realization of ultracold heteronuclear Feshbach molecules.
The molecules are created at individual sites of a 3D optical lattice. We
discuss lifetime, binding energy and rf association efficiency in terms of a
universal model and give an outlook for possible future developments.


title: On the compactification of concave ends

abstract:
  Let X be a complex manifold of dimension 2, which admits a strictly
plurisubharmonic function r which is proper as a function with values in the
intervall ]inf r, sup r[. We prove that the concave end of X can be
compactified, if and only if, the first cohomology of X is Hausdorff.


title: Modeling of Body Mass Index by Newton's Second Law

abstract:
  Since laws of physics exist in nature, their possible relationship to
terrestial growth is introduced. By considering the human body as a dynamic
system of variable mass (and volume), growing under a gravity field, it is
shown how natural laws may influence the vertical growth of humans. This
approach makes sense because the non-linear percentile curves of different
aspects of human physical growth from childhood to adolescence can be described
in relation to physics laws independently of gender and nationality. Analytical
relations for the dependence of stature, measured mass (weight), growth
velocity (and their mix as the body mass index) on age are deduced with a set
of common statistical parameters which could relate environmental, genetics and
metabolism and different aspects of physical growth on earth. A relationship to
the monotone smoothing using functional data analysis to estimate growth curves
and its derivatives is established. A preliminary discussion is also presented
on horizontal growth in an essentially weightless environment (i.e., aquatic)
with a connection to the Laird-Gompertz formula for growth.


title: Spin-lozenge thermodynamics and magnetic excitations in Na$_3$RuO$_4$

abstract:
  We report inelastic and elastic neutron scattering, magnetic susceptibility,
and heat capacity measurements of polycrystalline sodium ruthenate
(Na$_3$RuO$_4$). Previous work suggests this material consists of isolated
tetramers of $S=3/2$ Ru$^{5+}$ ions in a so-called "lozenge" configuration.
Using a Heisenberg antiferromagnet Hamiltonian, we analytically determine the
energy eigenstates for general spin $S$. From this model, the neutron
scattering cross-sections for excitations associated with spin-3/2
spin-tetramer configurations is determined. Comparison of magnetic
susceptibility and inelastic neutron scattering results shows that the proposed
"lozenge" model is not distinctly supported, but provides evidence that the
system may be better described as a pair of non-interacting inequivalent
dimers, \textit{i.e} double dimers. However, the existence of long-range
magnetic order below $T_c \approx 28$ K immediately questions such a
description. Although no evidence of the lozenge model is observed, future
studies on single crystals may further clarify the appropriate magnetic
Hamiltonian.


title:
Testing the Dark Matter Interpretation of the DAMA/LIBRA Result with
  Super-Kamiokande

abstract:
  We consider the prospects for testing the dark matter interpretation of the
DAMA/LIBRA signal with the Super-Kamiokande experiment. The DAMA/LIBRA signal
favors dark matter with low mass and high scattering cross section. We show
that these characteristics imply that the scattering cross section that enters
the DAMA/LIBRA event rate determines the annihilation rate probed by
Super-Kamiokande. Current limits from Super-Kamiokande through-going events do
not test the DAMA/LIBRA favored region. We show, however, that upcoming
analyses including fully-contained events with sensitivity to dark matter
masses from 5 to 10 GeV may corroborate the DAMA/LIBRA signal. We conclude by
considering three specific dark matter candidates, neutralinos, WIMPless dark
matter, and mirror dark matter, which illustrate the various model-dependent
assumptions entering our analysis.


title: Latest supernovae constraints on f(R) cosmologies

abstract:
  A class of modified gravity, known as $f(R)$-gravity, has presently been
applied to Cosmology as a realistic alternative to dark energy. In this paper
we use the most recent Type-Ia Supernova (SNe Ia) data, the so-called
\emph{Union} sample of 307 SNe Ia, to place bounds on a theory of the form
$f(R)=R - \beta/R^n$ within the Palatini approach. Given the complementarity of
SNe Ia data with other cosmological observables, a joint analysis with
measurements of baryon acoustic oscillation peak and estimates of the {\rm CMB}
shift parameter is also performed. We show that, for the allowed intervals of
$n$, $\Omega_{mo}$, and $\beta$, models based on $f(R) = R - \beta/R^{n}$
gravity in the Palatini approach can produce the sequence of
radiation-dominated, matter-dominated, and accelerating periods without need of
dark energy.


title: PAHs in Comets: An Overview

abstract:
  Polycyclic aromatic hydrocarbon (PAH) molecules, ubiquitously seen in the
interstellar medium (ISM) of our own and external galaxies, might have been
incorporated into comets if they are formed from relatively unprocessed
interstellar matter. The detection of PAHs in comets would be an important link
between the ISM and comets. This review compiles our current knowledge on
cometary PAHs, based on ground-based and space-borne observations of infrared
vibrational and ultraviolet fluorescence spectra of comets, and laboratory
analysis of interplanetary dust particles possibly of cometary origin and
cometary samples returned to Earth by the Stardust spacecraft. The latter
provided the most unambiguous evidence for the presence of PAHs in cometary
nuclei.


title:
Constraining the AGN Contribution in a Multiwavelength Study of Seyfert
  Galaxies

abstract:
  We have studied the relationship between the high- and low-ionization [O IV]
lambda 25.89 micron, [Ne III] lambda 15.56 micron and [Ne II] lambda 12.81
micron emission lines with the aim of constraining the active galactic nuclei
(AGN) and star formation contributions for a sample of 103 Seyfert galaxies. We
used the [O IV] and [Ne II] emission as tracers for the AGN power and star
formation to investigate the ionization state of the emission-line gas. We find
that Seyfert 2 galaxies have, on average, lower [O IV]/[Ne II] ratios than
those of Seyfert 1 galaxies. This result suggests two possible scenarios: 1)
Seyfert 2 galaxies have intrinsically weaker AGN, or 2) Seyfert 2 galaxies have
relatively higher star formation rates than Seyfert 1 galaxies. We estimate the
fraction of [Ne II] directly associated with the AGN and find that Seyfert 2
galaxies have a larger contribution from star formation, by a factor of ~1.5 on
average, than what is found in Seyfert 1 galaxies. Using the stellar component
of [Ne II] as a tracer of the current star formation we found similar star
formation rates in Seyfert 1 and Seyfert 2 galaxies. We examined the mid- and
far-infrared continua and find that [Ne II] is well correlated with the
continuum luminosity at 60 micron and that both [Ne III] and [O IV] are better
correlated with the 25 micron luminosities than with the continuum at longer
wavelengths, suggesting that the mid-infrared continuum luminosity is dominated
by the AGN, while the far-infrared luminosity is dominated by star formation.
Overall, these results test the unified model of AGN, and suggest that the
differences between Seyfert galaxies cannot be solely due to viewing angle
dependence.


title: Quiver Chern-Simons theories and crystals

abstract:
  We consider N=2 quiver Chern-Simons theories described by brane tilings,
whose moduli spaces are toric Calabi-Yau 4-folds. Simple prescriptions to
obtain toric data of the moduli space and a corresponding brane crystal from a
brane tiling are proposed.


title: Rate-Distortion via Markov Chain Monte Carlo

abstract:
  We propose an approach to lossy source coding, utilizing ideas from Gibbs
sampling, simulated annealing, and Markov Chain Monte Carlo (MCMC). The idea is
to sample a reconstruction sequence from a Boltzmann distribution associated
with an energy function that incorporates the distortion between the source and
reconstruction, the compressibility of the reconstruction, and the point sought
on the rate-distortion curve. To sample from this distribution, we use a `heat
bath algorithm': Starting from an initial candidate reconstruction (say the
original source sequence), at every iteration, an index i is chosen and the
i-th sequence component is replaced by drawing from the conditional probability
distribution for that component given all the rest. At the end of this process,
the encoder conveys the reconstruction to the decoder using universal lossless
compression. The complexity of each iteration is independent of the sequence
length and only linearly dependent on a certain context parameter (which grows
sub-logarithmically with the sequence length). We show that the proposed
algorithms achieve optimum rate-distortion performance in the limits of large
number of iterations, and sequence length, when employed on any stationary
ergodic source. Experimentation shows promising initial results. Employing our
lossy compressors on noisy data, with appropriately chosen distortion measure
and level, followed by a simple de-randomization operation, results in a family
of denoisers that compares favorably (both theoretically and in practice) with
other MCMC-based schemes, and with the Discrete Universal Denoiser (DUDE).


title:
No Evidence for Variability of Intervening Absorption Lines toward GRB
  060206: Implications for the Mg II Incidence Problem

abstract:
  We examine variability of absorption line strength of intervening systems
along the line of sight to GRB 060206 at $z = 4.05$, by the low-resolution
optical spectra obtained by the Subaru telescope from six to ten hours after
the burst. Strong variabilities of Fe\emissiontype{II} and Mg\emissiontype{II}
lines at $z=1.48$ during $t=$5--8 hours have been reported for this GRB
\citep{Hao07}, and this has been used to support the idea of clumpy
Mg\emissiontype{II} cloudlets that was originally proposed to explain the
anomalously high incidence of Mg\emissiontype{II} absorbers in GRB spectra
compared with quasars . However, our spectra with higher signal-to-noise ratio
do not show any evidence for variability in $t=$6-10 hours. There is a clear
discrepancy between our data and Hao et al. data in the overlapping time
interval. Furthermore, the line strengths in our data are in good agreement
with those observed at $t \sim$ 2 hours by \citet{Tho08}. We also detected
Fe\emissiontype{II} and Mg\emissiontype{II} absorption lines for a system at $z
= 2.26$, and these lines do not show evidence for variability either. Therefore
we conclude that there is no strong evidence for variability of intervening
absorption lines toward GRB 060206, significantly weakening the support to the
Mg\emissiontype{II} cloudlet hypothe sis by the GRB 060206 data.


title: Stability criteria for q-expectation values

abstract:
  In statistical physics lately a specific kind of average, called the
q-expectation value, has been extensively used in the context of q-generalized
statistics dealing with distributions following power-laws. In this context
q-expectation values appear naturally. After it has been recently shown that
this non-linear functional is instable, under a very strong notion of
stability, it is therefore of high interest to know sufficient conditions for
when the results of q-expectations are robust under small variations of the
underlying distribution function. We show that reasonable restrictions on the
domain of admissible probability distributions restore uniform continuity for
the q-expectation. Bounds on the size of admissible variations can be given.
The practical usefulness of the theorems for estimating the robustness of the
q-expectation value with respect to small variations is discussed.


title:
A model for the waveform behavior of accreting millisecond pulsars:
  Nearly aligned magnetic fields and moving emission regions

abstract:
  We investigate further a model of the accreting millisecond X-ray pulsars we
proposed earlier. In this model, the X-ray-emitting regions of these pulsars
are near their spin axes but move. This is to be expected if the magnetic poles
of these stars are close to their spin axes, so that accreting gas is channeled
there. As the accretion rate and the structure of the inner disk vary, gas is
channeled along different field lines to different locations on the stellar
surface, causing the X-ray-emitting areas to move. We show that this "nearly
aligned moving spot model" can explain many properties of the accreting
millisecond X-ray pulsars, including their generally low oscillation amplitudes
and nearly sinusoidal waveforms; the variability of their pulse amplitudes,
shapes, and phases; the correlations in this variability; and the similarity of
the accretion- and nuclear-powered pulse shapes and phases in some. It may also
explain why accretion-powered millisecond pulsars are difficult to detect, why
some are intermittent, and why all detected so far are transients. This model
can be tested by comparing with observations the waveform changes it predicts,
including the changes with accretion rate.


title:
Using Relative Entropy to Find Optimal Approximations: an Application to
  Simple Fluids

abstract:
  We develop a maximum relative entropy formalism to generate optimal
approximations to probability distributions. The central results consist in (a)
justifying the use of relative entropy as the uniquely natural criterion to
select a preferred approximation from within a family of trial parameterized
distributions, and (b) to obtain the optimal approximation by marginalizing
over parameters using the method of maximum entropy and information geometry.
As an illustration we apply our method to simple fluids. The "exact" canonical
distribution is approximated by that of a fluid of hard spheres. The proposed
method first determines the preferred value of the hard-sphere diameter, and
then obtains an optimal hard-sphere approximation by a suitably weighed average
over different hard-sphere diameters. This leads to a considerable improvement
in accounting for the soft-core nature of the interatomic potential. As a
numerical demonstration, the radial distribution function and the equation of
state for a Lennard-Jones fluid (argon) are compared with results from
molecular dynamics simulations.

categories: cond-mat.stat-mech cs.IT math.IT math.PR physics.data-an


title:
Periodic Radio and H-alpha Emission from the L Dwarf Binary 2MASSW
  J0746425+200032: Exploring the Magnetic Field Topology and Radius of an L
  Dwarf

abstract:
  [Abridged] We present an 8.5-hour simultaneous radio, X-ray, UV, and optical
observation of the L dwarf binary 2MASSW J0746+20. We detect strong radio
emission, dominated by short-duration periodic pulses at 4.86 GHz with
P=124.32+/-0.11 min. The stability of the pulse profiles and arrival times
demonstrates that they are due to the rotational modulation of a B~1.7 kG
magnetic field. A quiescent non-variable component is also detected, likely due
to emission from a uniform large-scale field. The H-alpha emission exhibits
identical periodicity, but unlike the radio pulses it varies sinusoidally and
is offset by exactly 1/4 of a phase. The sinusoidal variations require
chromospheric emission from a large-scale field structure, with the radio
pulses likely emanating from the magnetic poles. While both light curves can be
explained by a rotating mis-aligned magnetic field, the 1/4 phase lag rules out
a symmetric dipole topology since it would result in a phase lag of 1/2
(poloidal field) or zero (toroidal field). We therefore conclude that either
(i) the field is dominated by a quadrupole configuration, which can naturally
explain the 1/4 phase lag; or (ii) the H-alpha and/or radio emission regions
are not trivially aligned with the field. Regardless of the field topology, we
use the measured period along with the known rotation velocity (vsini=27 km/s),
and the binary orbital inclination (i=142 deg), to derive a radius for the
primary star of 0.078+/-0.010 R_sun. This is the first measurement of the
radius of an L dwarf, and along with a mass of 0.085+/-0.010 M_sun it provides
a constraint on the mass-radius relation below 0.1 M_sun. We find that the
radius is about 30% smaller than expected from theoretical models, even for an
age of a few Gyr.


title:
Evolving black hole-neutron star binaries in general relativity using
  pseudospectral and finite difference methods

abstract:
  We present a code for solving the coupled Einstein-hydrodynamics equations to
evolve relativistic, self-gravitating fluids. The Einstein field equations are
solved in generalized harmonic coordinates on one grid using pseudospectral
methods, while the fluids are evolved on another grid using shock-capturing
finite difference or finite volume techniques. We show that the code accurately
evolves equilibrium stars and accretion flows. Then we simulate an equal-mass
nonspinning black hole-neutron star binary, evolving through the final four
orbits of inspiral, through the merger, to the final stationary black hole. The
gravitational waveform can be reliably extracted from the simulation.


title:
Electron Spin Dephasing due to Hyperfine Interactions with a Nuclear
  Spin Bath

abstract:
  We investigate pure dephasing decoherence (free induction decay and spin
echo) of a spin qubit interacting with a nuclear spin bath. While for infinite
magnetic field B the only decoherence mechanism is spectral diffusion due to
dipolar flip-flops of nuclear spins, with decreasing B the hyperfine-mediated
interactions between the nuclear spins become important. We give a theory of
decoherence due to these interactions which takes advantage of their long-range
nature. For a thermal uncorrelated bath we show that our theory is applicable
down to B~10 mT, allowing for comparison with recent experiments in GaAs
quantum dots.


title: Can you hear the shape of a Beatty sequence?

abstract:
  Let K(x_1,...,x_d) be a polynomial. If you are not given the real numbers
\alpha_1, \alpha_2, ...,\alpha_d, but are given the polynomial K and the
sequence a_n=K(\floor{n\alpha_1},\floor{n\alpha_2},...,\floor{n\alpha_d}), can
you deduce the values of \alpha_i? Not, it turns out, in general. But with
additional irrationality hypotheses and certain polynomials, it is possible. We
also consider the problem of deducing \alpha_i from the integer sequence with
nested flooring (\floor{\floor{... \floor{\floor{n\alpha_1}\alpha_2}...
\alpha_{d-1}}\alpha_d})_{n=1}^\infty.


title:
Strongly Coupled Radiation from Moving Mirrors and Holography in the
  Karch-Randall model

abstract:
  Motivated by the puzzles in understanding how Black Holes evaporate into a
strongly coupled Conformal Field Theory, we study particle creation by an
accelerating mirror. We model the mirror as a gravitating Domain Wall and
consider a CFT coupled to it through gravity, in asymptotically Anti de Sitter
space. This problem (backreaction included) can be solved exactly at one loop.
At strong coupling, this is dual to a Domain Wall localized on the brane in the
Karch-Randall model, which can be fully solved as well. Hence, in this case one
can see how the particle production is affected by A) strong coupling and B)
its own backreaction. We find that A) the amount of CFT radiation at strong
coupling is not suppressed relative to the weak coupling result; and B) once
the boundary conditions in the AdS_5 bulk are appropriately mapped to the
conditions for the CFT on the boundary of AdS_4, the Karch-Randall model and
the CFT side agree to leading order in the backreaction. This agreement holds
even for a new class of self-consistent solutions (the `Bootstrap' Domain Wall
spacetimes) that have no classical limit. This provides a quite precise check
of the holographic interpretation of the Karch-Randall model. We also comment
on the massive gravity interpretation.
  As a byproduct, we show that relativistic Cosmic Strings (pure tension
codimension 2 branes) in Anti de Sitter are repulsive and generate long-range
tidal forces even at classical level. This is the phenomenon dual to particle
production by Domain Walls.


title: Galaxy Clusters in the Swift/BAT era: Hard X-rays in the ICM

abstract:
  We report about the detection of 10 clusters of galaxies in the ongoing
Swift/BAT all-sky survey. This sample, which comprises mostly merging clusters,
was serendipitously detected in the 15--55 keV band. We use the BAT sample to
investigate the presence of excess hard X-rays above the thermal emission. The
BAT clusters do not show significant (e.g. >2 $\sigma$) non-thermal hard X-ray
emission. The only exception is represented by Perseus whose high-energy
emission is likely due to NGC 1275. Using XMM-Newton, Swift/XRT, Chandra and
BAT data, we are able to produce upper limits on the Inverse Compton (IC)
emission mechanism which are in disagreement with most of the previously
claimed hard X-ray excesses. The coupling of the X-ray upper limits on the IC
mechanism to radio data shows that in some clusters the magnetic field might be
larger than 0.5 $\mu$G. We also derive the first logN-logS and luminosity
function distribution of galaxy clusters above 15 keV.


title: Searching supersymmetry at the LHCb with displaced vertices

abstract:
  Supersymmetric theories with bilinear R-parity violation can give rise to the
observed neutrino masses and mixings. One important feature of such models is
that the lightest supersymmetric particle might have a sufficiently large
lifetime to give rise to detached vertices. Working in the framework of
supergravity models we analyze the potential of the LHCb experiment to search
for supersymmetric models exhibiting bilinear R-parity violation. We show that
the LHCb experiment can probe a large fraction of the $m_0 \otimes m_{1/2}$
being able to explore gluino masses up to 1.3 TeV. The LHCb discover potential
for this kind of models is similar to the ATLAS and CMS ones in the low
luminosity phase of operation of the LHC.


title:
On the Theoretical Possibility of Quantum Visual Information Transfer to
  the Human Brain

abstract:
  The feasibility of wave function collapse in the human brain has been the
subject of vigorous scientific debates since the advent of quantum theory.
Scientists like Von Neumann, London, Bauer and Wigner (initially) believed that
wave function collapse occurs in the brain or is caused by the mind of the
observer. It is a legitimate question to ask how human brain can receive subtle
external visual quantum information intact when it must pass through very noisy
and complex pathways from the eye to the brain? There are several approaches to
investigate information processing in the brain, each of which presents a
different set of conclusions. Penrose and Hameroff have hypothesized that there
is quantum information processing inside the human brain whose material
substrate involves microtubules and consciousness is the result of a collective
wavefunction collapse occurring in these structures. Conversely, Tegmark stated
that owing to thermal decoherence there cannot be any quantum processing in
neurons of the brain and processing in the brain must be classical for
cognitive processes. However, Rosa and Faber presented an argument for a middle
way which shows that none of the previous authors are completely right and
despite the presence of decoherence, it is still possible to consider the brain
to be a quantum system. Additionally, Thaheld, has concluded that quantum
states of photons do collapse in the human eye and there is no possibility for
collapse of visual quantum states in the brain and thus there is no possibility
for the quantum state reduction in the brain. In this paper we conclude that if
we accept the main essence of the above approaches taken together, each of them
can provide a different part of a teleportation mechanism.


title:
Distributed Parameter Estimation in Sensor Networks: Nonlinear
  Observation Models and Imperfect Communication

abstract:
  The paper studies distributed static parameter (vector) estimation in sensor
networks with nonlinear observation models and noisy inter-sensor
communication. It introduces \emph{separably estimable} observation models that
generalize the observability condition in linear centralized estimation to
nonlinear distributed estimation. It studies two distributed estimation
algorithms in separably estimable models, the $\mathcal{NU}$ (with its linear
counterpart $\mathcal{LU}$) and the $\mathcal{NLU}$. Their update rule combines
a \emph{consensus} step (where each sensor updates the state by weight
averaging it with its neighbors' states) and an \emph{innovation} step (where
each sensor processes its local current observation.) This makes the three
algorithms of the \textit{consensus + innovations} type, very different from
traditional consensus. The paper proves consistency (all sensors reach
consensus almost surely and converge to the true parameter value,) efficiency,
and asymptotic unbiasedness. For $\mathcal{LU}$ and $\mathcal{NU}$, it proves
asymptotic normality and provides convergence rate guarantees. The three
algorithms are characterized by appropriately chosen decaying weight sequences.
Algorithms $\mathcal{LU}$ and $\mathcal{NU}$ are analyzed in the framework of
stochastic approximation theory; algorithm $\mathcal{NLU}$ exhibits mixed
time-scale behavior and biased perturbations, and its analysis requires a
different approach that is developed in the paper.


title:
Needlet Detection of Features in WMAP CMB Sky and the Impact on
  Anisotropies and Hemispherical Asymmetries

abstract:
  We apply spherical needlets to the Wilkinson Microwave Anisotropy Probe
5-year cosmic microwave background (CMB) dataset, to search for imprints of
non-isotropic features in the CMB sky. We use the needlets localization
properties to resolve peculiar features in the CMB sky and to study how these
features contribute to the anisotropy power spectrum of the CMB. In addition to
the now well-known "cold spot" of the CMB map in the southern hemisphere, we
also find two hot spots at greater than 99% confidence level, again in the
southern hemisphere and closer to the Galactic plane. While the cold spot
contributes to the anisotropy power spectrum in the multipoles between l=6 to
l=33, the hot spots are found to be dominating the anisotropy power in the
range between l=6 and l=18. Masking both the cold and the two hot spots results
in a reduction by about 15% in the amplitude of the angular power spectrum of
CMB around l=10. The resulting changes to the cosmological parameters when the
power spectrum is estimated masking these features (in addition to the WMAP
team's KQ85 mask) are within the 1$\sigma$ errors published with the WMAP mask
only. We also study the asymmetry between the angular power spectra evaluated
on the northern and southern hemispheres. When the features detected by
needlets are masked, we find that the difference in the power, measured in
terms of the anisotropy variance between l=4 and l=18, is reduced by a factor
2. We make available a mask related to needlet features for more detailed
studies on asymmetries in the CMB anisotropy sky.


title: Jamming as Information: a Geometric Approach

abstract:
  In this paper I discuss the kinds of information that can be extracted by our
enemy if our jamming is too precise. I show geometric solutions for
reconstructing linear routes given certain information about them, such as the
shortest distance to a point or the times of entering and exiting a circle.


title: Propagation Effects in Magnetized Transrelativistic Plasmas

abstract:
  The transfer of polarized radiation in magnetized and non-magnetized
relativistic plasmas is an area of research with numerous flaws and gaps. The
present paper is aimed at filling some gaps and eliminating the flaws. Starting
from a Trubnikov's linear response tensor for a vacuum wave with ${\bf
k}=\omega/c$ in thermal plasma, the analytic expression for the dielectric
tensor is found in the limit of high frequencies. The Faraday rotation and
Faraday conversion measures are computed in their first orders in the ratio of
the cyclotron frequency $\Omega_0$ to the observed frequency $\omega$. The
computed temperature dependencies of propagation effects bridge the known
non-relativistic and ultra-relativistic limiting formulas. The fitting
expressions are found for high temperatures, where the higher orders in
$\Omega_0/\omega$ cannot be neglected. The plasma eigenmodes are found to
become linearly polarized at much larger temperatures than thought before. The
results are applied to the diagnostics of the hot ISM, hot accretion flows, and
jets.


title:
Situational diagnosis for preservice elementary teachers on some basic
  astronomical phenomena

abstract:
  The present situation of the teaching-learning relationship in astronomy is
rarely investigated in our country. This is so, even when it is widely
recognized that astronomy is an integral discipline, at the crossroads of
advances in physics, geology, chemistry, etc. In this project we aim at
contributing with the situational diagnosis in topics of astronomy of
preservice elementary teachers, and to try and develop didactic tools that
better collaborate with their formal education. We work with an open written
questionnaire, designed to put in evidence some of the most frequently used
models on a few basic astronomical notions. We here describe the main questions
included in the test, and show our first results and some conclusions after
having addressed the questionnaire to a number of preservice elementary
teachers.


title:
Spin Fluctuation Dynamics and Multiband Superconductivity in Iron
  Pnictides

abstract:
  Multiband superconductivity, involving resonant pair scattering between
different bands, has emerged as a possible explanation of some of the main
characteristics of the recently discovered iron pnictides. A key feature of
such interband pairing mechanism is that it can generate or enhance
superconducting pairing irrespective of whether it is attractive or repulsive.
The latter case typically leads to the superconducting gap switching its sign
among different sections of the Fermi surface. In iron pnictides, the natural
scenario is that the gap changes sign between the hole and the electron Fermi
surfaces. However, the macroscopic symmetry of such an extended s'-wave state
still belongs to the general s-wave category, raising the question of how to
distinguish it from an ordinary s-wave. In such a quest, it is essential to use
experimental techniques that have a momentum space resolution and can probe
momenta of order M, the wavevector that separates the hole and the electron
Fermi surfaces in the Brillouin zone. Here we study experimental signatures in
the spin fluctuation dynamics of the fully-gapped s- and s'-wave
superconducting states, as well as those of the nodal d- and p-wave. The
coupling between spin fluctuations of the incipient nearly-nested spin
density-wave (SDW) and the Bogoliubov-deGennes quasiparticles of the
superconducting state leads to the Landau-type damping of the former. The
intrinsic structure of the superconducting gap leaves a distinctive signature
in the form of this damping, allowing it to be used to diagnose the nature of
iron-based superconductivity in neutron scattering and other experiments
sensitive to spin fluctuations in momentum space. We also discuss the
coexistence between superconductivity and SDW order.


title:
On the structure of the Sun and alpha Centauri A and B in the light of
  seismic and non-seismic constraints

abstract:
  The small separation (delta nu 01, delta nu 02 and delta nu 13) between the
oscillations with low degree l is dependent primarily on the sound speed
profile within the stellar core, where nuclear evolution occurs. The detection
of such oscillations for a star offers a very good opportunity to determine the
stage of its nuclear evolution, and hence its age. In this context, we
investigate the Sun and alpha Cen A and B. For alpha Cen A and B, each of the
small separations delta nu 01, delta nu 02 and delta nu 13 gives a different
age. Therefore, in our fitting process, we also employ the second difference,
defined as nu n2 - 2 nu n1 + nu n0, which is 2 delta nu 01- delta nu 02. In
addition to this, we also use frequency ratio (nu n0/ nu n2). For the Sun,
these expressions areequivalent and give an age of about 4.9-5.0 Gyr. For alpha
Cen A and B, however, the small separation and the second difference give very
different ages. This conflict may be solved by the detection of oscillation
frequencies that can be measured much more precisely than the current
frequencies. When we fit the models to the observations, we find (i) Z 0=0.020,
t=3.50 Gyr and M B=1.006 Msun from the small separations delta nu 01, delta nu
02 and delta nu 13 of alpha Cen B; and (ii) a variety of solutions from the
non-seismic constraints and delta nu 02 of alpha Cen A and B, in which the
masses of alpha Cen A and B are slightly modified and the age of the system is
about 5.2-5.3 Gyr. For Z=0.025, the closest masses we find to the observed
masses are M B=0.922 Msun and M A=1.115 Msun.The differences between these
masses and the corresponding observed masses are about 0.01 Msun.


title: An overview of the transmission capacity of wireless networks

abstract:
  This paper surveys and unifies a number of recent contributions that have
collectively developed a metric for decentralized wireless network analysis
known as transmission capacity. Although it is notoriously difficult to derive
general end-to-end capacity results for multi-terminal or \adhoc networks, the
transmission capacity (TC) framework allows for quantification of achievable
single-hop rates by focusing on a simplified physical/MAC-layer model. By using
stochastic geometry to quantify the multi-user interference in the network, the
relationship between the optimal spatial density and success probability of
transmissions in the network can be determined, and expressed -- often fairly
simply -- in terms of the key network parameters. The basic model and
analytical tools are first discussed and applied to a simple network with path
loss only and we present tight upper and lower bounds on transmission capacity
(via lower and upper bounds on outage probability). We then introduce random
channels (fading/shadowing) and give TC and outage approximations for an
arbitrary channel distribution, as well as exact results for the special cases
of Rayleigh and Nakagami fading. We then apply these results to show how TC can
be used to better understand scheduling, power control, and the deployment of
multiple antennas in a decentralized network. The paper closes by discussing
shortcomings in the model as well as future research directions.


title: On cuspidal sections of algebraic fundamental groups

abstract:
  Rational points in the boundary of a hyperbolic curve over a field with
sufficiently nontrivial Kummer theory are the source for an abundance of
sections of the fundamental group exact sequence. We follow and refine
Nakamura's approach towards these boundary sections. For example, we obtain a
weak anabelian theorem for hyperbolic genus 0 curves over quite general fields
including for example the maximal abelian extension of the rational numbers.


title: Second symmetric powers of chain complexes

abstract:
  We investigate Buchbaum and Eisenbud's construction of the second symmetric
power S^2_R(X) of a chain complex X of modules over a commutative ring R. We
state and prove a number of results from the folklore of the subject for which
we know of no good direct references. We also provide several explicit
computations and examples. We use this construction to prove the following
version of a result of Avramov, Buchweitz, and Sega: Let R \to S be a
module-finite ring homomorphism such that R is noetherian and local, and such
that 2 is a unit in R. Let X be a complex of finite rank free S-modules such
that X_n = 0 for each n < 0. If \cup_n Ass_R(H_n(X \otimes_S X)) \subseteq
Ass(R) and if X_P \simeq S_P for each P \in Ass(R), then X \simeq S.


title: Comodules for some simple $\mathcal O$-forms of $\mathbb G_m$

abstract:
  This paper gives a rather concrete description of the category Rep(G) for
certain flat commutative affine group schemes G over a discrete valuation ring
such that the general fiber of G is the multiplicative group.


title: On modular forms for some noncongruence subgroups of SL_2(Z) II

abstract:
  In this paper we show two classes of noncongruence subgroups satisfy the
so-called unbounded denominator property. In particular, we establish our
conjecture in [KL08] which says that every type II noncongruence character
group of Gamma^0(11) satisfies the unbounded denominator property.


title: A spectral method for elliptic equations: the Dirichlet problem

abstract:
  An elliptic partial differential equation Lu=f with a zero Dirichlet boundary
condition is converted to an equivalent elliptic equation on the unit ball. A
spectral Galerkin method is applied to the reformulated problem, using
multivariate polynomials as the approximants. For a smooth boundary and smooth
problem parameter functions, the method is proven to converge faster than any
power of 1/n with n the degree of the approximate Galerkin solution. Examples
in two and three variables are given as numerical illustrations. Empirically,
the condition number of the associated linear system increases like O(N), with
N the order of the linear system.


title:
Lagrangians for dissipative nonlinear oscillators: the method of Jacobi
  Last Multiplier

abstract:
  We present a method devised by Jacobi to derive Lagrangians of any
second-order differential equation: it consists in finding a Jacobi Last
Multiplier. We illustrate the easiness and the power of Jacobi's method by
applying it to several equations and also a class of equations studied by
Musielak with his own method [Musielak ZE, Standard and non-standard
Lagrangians for dissipative dynamical systems with variable coefficients. J.
Phys. A: Math. Theor. 41 (2008) 055205 (17pp)], and in particular to a
Li\`enard type nonlinear oscillator, and a second-order Riccati equation.


title:
Production of Almost Fermiophobic Gauge Bosons in the Minimal Higgsless
  Model at the LHC

abstract:
  We study the production of the heavy W' and Z' bosons in the three site
higgsless model at the LHC. We focus on the s-channel production mode to
estimate the prospects for measuring their suppressed couplings to standard
model fermions.


title: Game Theory with Costly Computation

abstract:
  We develop a general game-theoretic framework for reasoning about strategic
agents performing possibly costly computation. In this framework, many
traditional game-theoretic results (such as the existence of a Nash
equilibrium) no longer hold. Nevertheless, we can use the framework to provide
psychologically appealing explanations to observed behavior in well-studied
games (such as finitely repeated prisoner's dilemma and rock-paper-scissors).
Furthermore, we provide natural conditions on games sufficient to guarantee
that equilibria exist. As an application of this framework, we consider a
notion of game-theoretic implementation of mediators in computational games. We
show that a special case of this notion is equivalent to a variant of the
traditional cryptographic definition of protocol security; this result shows
that, when taking computation into account, the two approaches used for dealing
with "deviating" players in two different communities -- Nash equilibrium in
game theory and zero-knowledge "simulation" in cryptography -- are intimately
related.


title: The length of time's arrow

abstract:
  An unresolved problem in physics is how the thermodynamic arrow of time
arises from an underlying time reversible dynamics. We contribute to this issue
by developing a measure of time-symmetry breaking, and by using the work
fluctuation relations, we determine the time asymmetry of recent single
molecule RNA unfolding experiments. We define time asymmetry as the
Jensen-Shannon divergence between trajectory probability distributions of an
experiment and its time-reversed conjugate. Among other interesting properties,
the length of time's arrow bounds the average dissipation and determines the
difficulty of accurately estimating free energy differences in nonequilibrium
experiments.


title: Gauge Mediation with D-terms

abstract:
  I propose implementing General Gauge Mediation using the class of $SU(N)
\times U(1)$ SUSY breaking models. As an existence proof, I have utilized the
4-1 model in building multi-parameter gauge mediation. These hidden sectors are
relatively easy to use and avoid several model building pitfalls such as
runaway directions. In addition models require no special tuning and may
produce as many parameters as general gauge mediation allows.


title: Kramers Theory for Conformational Transitions of Macromolecules

abstract:
  We consider the application of Kramers theory to the microscopic calculation
of rates of conformational transitions of macromolecules. The main difficulty
in such an approach is to locate the transition state in a huge configuration
space. We present a method which identifies the transition state along the most
probable reaction pathway. It is then possible to microscopically compute the
activation energy, the damping coefficient, the eigenfrequencies at the
transition state and obtain the rate, without any a-priori choice of a reaction
coordinate. Our theoretical results are tested against the results of Molecular
Dynamics simulations for transitions in a 2-dimensional double well and for the
cis-trans isomerization of a linear molecule.


title:
The index of projective families of elliptic operators: the decomposable
  case

abstract:
  An index theory for projective families of elliptic pseudodifferential
operators is developed when the twisting, i.e. Dixmier-Douady, class is
decomposable. One of the features of this special case is that the
corresponding Azumaya bundle can be realized in terms of smoothing operators.
The topological and the analytic index of a projective family of elliptic
operators both take values in the twisted K-theory of the parameterizing space.
The main result is the equality of these two notions of index. The twisted
Chern character of the index class is then computed by a variant of Chern-Weil
theory.


title: A Dual Role for Sex?

abstract:
  The two classic theories for the existence of sexual replication are that sex
purges deleterious mutations from a population, and that sex allows a
population to adapt more rapidly to changing environments. These two theories
have often been presented as opposing explanations for the existence of sex.
Here, we develop and analyze evolutionary models based on the asexual and
sexual replication pathways in Saccharomyces cerevisiae (Baker's yeast), and
show that sexual replication can both purge deleterious mutations in a static
environment, as well as lead to faster adaptation in a dynamic environment.
This implies that sex can serve a dual role, which is in sharp contrast to
previous theories.


title:
The Masses of Transition Circumstellar Disks: Observational Support for
  Photoevaporation Models

abstract:
  We report deep Sub-Millimeter Array observations of 26 pre-main-sequence
(PMS) stars with evolved inner disks. These observations measure the mass of
the outer disk (r ~20-100 AU) across every stage of the dissipation of the
inner disk (r < 10 AU) as determined by the IR spectral energy distributions
(SEDs). We find that only targets with high mid-IR excesses are detected and
have disk masses in the 1-5 M_Jup range, while most of our objects remain
undetected to sensitivity levels of M_DISK ~0.2-1.5 M_Jup. To put these results
in a more general context, we collected publicly available data to construct
the optical to millimeter wavelength SEDs of over 120 additional PMS stars. We
find that the near-IR and mid-IR emission remain optically thick in objects
whose disk masses span 2 orders of magnitude (~0.5-50 M_Jup). Taken together,
these results imply that, in general, inner disks start to dissipate only after
the outer disk has been significantly depleted of mass. This provides strong
support for photoevaporation being one of the dominant processes driving disk
evolution.


title: Dzyaloshinskii-Moriya interactions in valence bond systems

abstract:
  We investigate the effect of Dzyaloshinskii-Moriya interactions on the low
temperature magnetic susceptibility for a system whose low energy physics is
dominated by short-range valence bonds (singlets). Our general perturbative
approach is applied to specific models expected to be in this class, including
the Shastry-Sutherland model of the spin-dimer compound SrCu_2(BO_3)_2 and the
antiferromagnetic Heisenberg model of the recently discovered S=1/2 kagome
compound ZnCu_3(OH)_6Cl_2. The central result is that a short-ranged valence
bond phase, when perturbed with Dzyaloshinskii-Moriya interactions, will remain
time-reversal symmetric in the absence of a magnetic field but the
susceptibility will be nonzero in the T\to 0 limit. Applied to
ZnCu_3(OH)_6Cl_2, this model provides an avenue for reconciling experimental
results, such as the lack of magnetic order and lack of any sign of a spin gap,
with known theoretical facts about the kagome Heisenberg antiferromagnet.


title:
A Variational Inference Framework for Soft-In-Soft-Out Detection in
  Multiple Access Channels

abstract:
  We propose a unified framework for deriving and studying soft-in-soft-out
(SISO) detection in interference channels using the concept of variational
inference. The proposed framework may be used in multiple-access interference
(MAI), inter-symbol interference (ISI), and multiple-input multiple-outpu
(MIMO) channels. Without loss of generality, we will focus our attention on
turbo multiuser detection, to facilitate a more concrete discussion. It is
shown that, with some loss of optimality, variational inference avoids the
exponential complexity of a posteriori probability (APP) detection by
optimizing a closely-related, but much more manageable, objective function
called variational free energy. In addition to its systematic appeal, there are
several other advantages to this viewpoint. First of all, it provides unified
and rigorous justifications for numerous detectors that were proposed on
radically different grounds, and facilitates convenient joint detection and
decoding (utilizing the turbo principle) when error-control codes are
incorporated. Secondly, efficient joint parameter estimation and data detection
is possible via the variational expectation maximization (EM) algorithm, such
that the detrimental effect of inaccurate channel knowledge at the receiver may
be dealt with systematically. We are also able to extend BPSK-based SISO
detection schemes to arbitrary square QAM constellations in a rigorous manner
using a variational argument.


title:
The density of Lawrence-Krammer and non-conjugate braid representations
  of links

abstract:
  We use some Lie group theory and Budney's unitarization of the
Lawrence-Krammer representation, to prove that for generic parameters of
definite form the image of the representation (also on certain types of
subgroups) is dense in the unitary group. This implies that, except possibly
for closures of full-twist braids, all links have infinitely many conjugacy
classes of braid representations on any non-minimal number of (and at least 4)
strands.


title: Quantum random walks without walking

abstract:
  Quantum random walks have received much interest due to their non-intuitive
dynamics, which may hold the key to a new generation of quantum algorithms.
What remains a major challenge is a physical realization that is experimentally
viable and not limited to special connectivity criteria. We present a scheme
for walking on arbitrarily complex graphs, which can be realized using a
variety of quantum systems such as a BEC trapped inside an optical lattice.
This scheme is particularly elegant since the walker is not required to
physically step between the nodes; only flipping coins is sufficient.


title: The Kinematics of Circular Motion

abstract:
  In this paper we introduce a proposal for the kinematics of bodies in uniform
circular motion. This model could contribute for the explanation of the two
main problems of contemporary cosmology: dark matter and dark energy. We use
one of the physical properties of space - the gravitational waves - to define a
reference frame at rest with respect to the space and to determine a mechanism
for the synchronization of clocks. So we derive through a Postulate the
so-called transformations of Lorentz and a new velocity of the bodies in
uniform circular motion. This rotational velocity could contribute to clarify
both cosmological problems. This contribution would come from effects due to a
single phenomenon: the rotational velocity of bodies with respect to the
reference frame at rest on the space. And finally, we interpret physically the
Postulate - the major point in this model - which allows, inclusive, a
comparison with the Relativity Principle and also new theoretical previews.


title:
Correlation Classes on the Landscape: To What Extent is String Theory
  Predictive?

abstract:
  In light of recent discussions of the string landscape, it is essential to
understand the degree to which string theory is predictive. We argue that it is
unlikely that the landscape as a whole will exhibit unique correlations amongst
low-energy observables, but rather that different regions of the landscape will
exhibit different overlapping sets of correlations. We then provide a
statistical method for quantifying this degree of predictivity, and for
extracting statistical information concerning the relative sizes and overlaps
of the regions corresponding to these different correlation classes. Our method
is robust and requires no prior knowledge of landscape properties, and can be
applied to the landscape as a whole as well as to any relevant subset.


title: Simulation Studies of Nanomagnet-Based Architecture

abstract:
  We report a simulation study on interacting ensembles of Co nanomagnets that
can perform basic logic operations and propagate logic signals, where the state
variable is the magnetization direction. Dipole field coupling between
individual nanomagnets drives the logic functionality of the ensemble and
coordinated arrangements of the nanomagnets allow for the logic signal to
propagate in a predictable way. Problems with the integrity of the logic signal
arising from instabilities in the constituent magnetizations are solved by
introducing a biaxial anisotropy term to the Gibbs magnetic free energy of each
nanomagnet. The enhanced stability allows for more complex components of a
logic architecture capable of random combinatorial logic, including horizontal
wires, vertical wires, junctions, fanout nodes, and a novel universal logic
gate. Our simulations define the focus of scaling trends in nanomagnet-based
logic and provide estimates of the energy dissipation and time per nanomagnet
reversal.


title:
Path integral study of the role of correlation in exchange coupling of
  spins in double quantum dots and optical lattices

abstract:
  We explore exchange coupling of a pair of spins in a double dot and in an
optical lattice. Our algorithm uses the frequency of exchanges in a bosonic
path integral, evaluated with Monte Carlo. This algorithm is simple enough to
be a "black box" calculator, yet gives insights into the role of correlation
through two-particle probability densities, visualization of instantons, and
pair correlation functions. We map the problem to Hubbard model and see that
exchange and correlation renormalize the effective parameters, dramatically
lowering U at larger separations.


title:
Decoherence of coherent electronic excited state in the reaction center
  of the photosynthetic purple bacterium Rhodobacter sphaeroides

abstract:
  In this paper, we present a theoretical description to the quantum coherence
and decoherence phenomena of energy transfer in photosynthesis observed in a
recent experiment [see Science 316, 1462 (2007)]. As a successive two-color
laser pulses with selected frequencies cast on a sample of the photosynthetic
purple bacterium Rb. sphaeroides two resonant excitations of electrons in
chromophores can be generated. However, this effective two-level subsystem will
interact with its protein environment and decoherence is inevitable. We
describe this subsystem coupled with its environment as a dynamical spin-boson
model. The non-Markovian decoherence dynamics is described using a
quasi-adiabatic propagator path integral (QUAPI) approach. With the
photon-induced effective time-dependent level splitting energy and level flip
coupling coefficient between the two excited states and the environment-induced
non-Markovian decoherence dynamics, our theoretical result is in good agreement
with the experimental data.


title:
Phase Separation in two-Species Atomic Bose-Einstein Condensate with
  Interspecies Feshbach Resonance

abstract:
  We consider a mixture of two-species atomic Bose-Einstein codensates coupled
to a bound molecular state at zero temperature via interspecies Feshbach
resonance. The interspecies Feshbach coupling precludes the possibility of
doubly mixed phases while enables not only the pure molecular superfluid but
also the pure atomic superfluids to exist as distinct phases. We show that this
system is able to support a rich set of phase separations, including that
between two distinct mixed atom-molecule phases. We pay particular attention to
the effects of the Feschbach coupling and the particle collisions on the
miscibility of this multi-component condensate system.


title: A new family of iron pnictides: BaFeAs2 and BaFeSb2

abstract:
  We investigate the structural, electronic, and magnetic properties of the
hypothetical compound BaFePn2 (Pn = As and Sb), which is isostructural to the
parent compound of the high temperature superconductor LaFeAsO1-xFx. Using
density functional theory, we show that the Fermi surface, electronic structure
and the spin density wave instability of BaFePn2 are very similar to the Fe
based superconductors. Additionally, there are very dispersive metallic bands
of a spacer Pn layer, which are almost decoupled from FePn layer. Our results
show that experimental study of BaFePn2 can test the role of charge and
polarization fluctuation, importance of two dimensionality in mechanism of
superconductivity.


title:
Evidence for X(3872) --> psi(2S) gamma in B+/- --> X(3872) K+/- decays,
  and a study of B --> ccbar gamma K

abstract:
  In a search for B --> ccbar gamma K decays with the BaBar detector, where
ccbar includes J/psi and psi(2S), and K includes K+, Ks, and K*(892), we find
evidence for X(3872) --> J/psi gamma and X(3872) --> psi(2S) gamma with 3.6
sigma and 3.5 sigma significance, respectively. We measure the product of
branching fractions BR(B+ --> X(3872) K+) x BR(X(3872) --> J/psi gamma) = (2.8
+/- 0.8(stat.) +/- 0.2(syst.)) x 10^(-6) and BR(B+ --> X(3872) K+) x BR(X(3872)
--> psi(2S) gamma) = (9.9 +/- 2.9(stat.) +/- 0.6(syst.)) x 10^(-6).


title: Comment on `A collider signature of the supersymmetric golden region'

abstract:
  We show that $Z$ polarization measurement is useful for distinguishing the
signal decay chain of the `golden region' in the minimal supersymmetric
standard model(MSSM) parameter space, which involves the stop decay of $\tilde
t_2 \to \tilde t_1 + Z$, from other decay chains involving the neutralino decay
of $\tilde\chi_2^0 \to \tilde\chi_1^0 + Z$ in different MSSM scenarios.


title: Effect of Rattling Phonons on Sommerfeld Constant

abstract:
  By employing a numerical renormalization group technique, we evaluate
electronic specific heat coefficient $\gamma$ of the Anderson model coupled
with local anharmonic phonons for the oscillation of a caged atom. For the
rattling-type cage potential with a flat and wide region in the bottom, we find
that phonon-mediated attraction is largely enhanced. When the potential shape
is deformed from the rattling type, there occurs a cancellation between Coulomb
repulsion and the phonon-mediated attraction. In such a situation, spin and
charge fluctuations are comparable to each other, leading to the realization of
exotic electron-phonon complex state with large and magnetically robust
$\gamma$.


title: Diffusion and binding of finite-size particles in confined geometries

abstract:
  Describing the diffusion of particles through crowded, confined environments
with which they can interact is of considerable biological and technological
interest. Under conditions where the confinement dimensions become comparable
to the particle dimensions, steric interactions between particles, as well as
particle-wall interactions, will play a crucial role in determining transport
properties. To elucidate the effects of these interactions on particle
transport, we consider the diffusion and binding of finite-size particles
within a channel whose diameter is comparable to the size of the particles.
Using a simple lattice model of this process, we calculate the steady-state
current and density profiles of both bound and free particles in the channel.
We show that the system can exhibit qualitatively different behavior depending
on the ratio of the channel width to the particle size. We also perform
simulations of this system, and find excellent agreement with our analytic
results.


title: Time-periodic universes

abstract:
  In this letter we construct a new time-periodic solution of the vacuum
Einstein's field equations whose Riemann curvature norm takes the infinity at
some points. We show that this solution is intrinsically time-periodic and
describes a time-periodic universe with the "black hole". New physical
phenomena are investigated and new singularities are analyzed for this
universal model.


title:
Control of Domain Wall Position by Electrical Current in Structured
  Co/Ni Wire with Perpendicular Magnetic Anisotropy

abstract:
  We report the direct observation of the current-driven domain wall (DW)
motion by magnetic force microscopy in a structured Co/Ni wire with
perpendicular magnetic anisotropy. The wire has notches to define the DW
position. It is demonstrated that single current pulses can precisely control
the DW position from notch to notch with high DW velocity of 40 m/s.


title: Global search for new physics at CDF

abstract:
  A model-independent global search for new physics has been performed at the
CDF experiment. This search examines 399 final states, looking for
discrepancies between observation and the standard model expectation in
populations, kinematic shapes, bumps in mass distributions suggestive of new
resonances and the tails of the summed transverse momentum distribution. This
global search reveals no evidence of physics beyond the Standard Model in 2.0
fb^-1 of p-pbar collisions at sqrt(s)=1.96 TeV.


title:
Charm hadron production in relativistic heavy ion collisions within a
  quark combination model

abstract:
  We investigate the charm hadron production in relativistic heavy-ion
collisions with the quark combination model. The $p_{T}$ dependencies of the
charm baryon to meson ratios such as
$\frac{\Lambda_{c}+\bar{\Lambda}_{c}}{D^{0}+\bar{D}^{0}}$,
$\frac{\Lambda_{c}+\bar{\Lambda}_{c}}{D^{+}+D^{-}}$ and
$\frac{\Lambda_{c}+\bar{\Lambda}_{c}}{D_{s}^{+}+D_{s}^{-}}$ in Au+Au collisions
at 200 GeV are obtained. The charm baryon enhancement in the intermediate
$p_{T}$ range is very prominent, which further, together with the strangeness
enhancement, affect the charm hadron ratios and lead to a $\sim17%$ larger
charm cross-section given by PHENIX. The dependencies of the charm hadron
ratios on energy, centrality, and other parameters are also investigated.
Predictions of the charm hadron ratios for the upgrade of RHIC and for LHC are
presented.


title: High redshift galaxy surveys

abstract:
  A brief overview on the current status of the census of the early universe
population is given. Observational surveys of high redshift galaxies provide
direct opportunities to witness the cosmic dawn and to have better
understanding of how and when infant galaxies evolve into mature ones. It is a
much more astronomical approach in contrast to the physical approach of to
study the spatial fluctuation of cosmic microwave radiation. Recent findings in
these two areas greatly advanced our understanding of the early Universe. I
will describe the basic properties of several target objects we are looking for
and the concrete methods astronomers are using to discover those objects in
early Universe. My talk starts with Lyman alpha emitters and Lyman break
galaxies, then introduces a clever approach to use gravitational lensing effect
of clusters of galaxies to detect distant faint galaxies behind the clusters.
Finally I will touch on the status and prospects of surveys for quasars and
gamma-ray bursts.


title: Topological states and braiding statistics using quantum circuits

abstract:
  Using superconducting quantum circuits, we propose an approach to construct a
Kitaev lattice, i.e., an anisotropic spin model on a honeycomb lattice with
three types of nearest-neighbor interactions. We study two particular cases to
demonstrate topological states (i.e., the vortex and bond states) and show how
the braiding statistics can be revealed. Our approach provides an
experimentally realizable many-body system for demonstrating exotic properties
of topological phases.

categories: cond-mat.mes-hall cond-mat.stat-mech cond-mat.str-el cond-mat.supr-con quant-ph


title:
Quantum double and $\kappa$-Poincar\'e symmetries in (2+1)-gravity and
  Chern-Simons theory

abstract:
  We review the role of Drinfeld doubles and kappa-Poincare symmetries in
quantised (2+1)-gravity and Chern-Simons theory. We discuss the conditions
under which a given Hopf algebra symmetry is compatible with a Chern-Simons
theory and determine this compatibility explicitly for the Drinfeld doubles and
kappa-Poincare symmetries associated with the isometry groups of (2+1)-gravity.
In particular, we explain that the usual kappa-Poincare symmetries with a
timelike deformation are not directly associated with (2+1)-gravity. These
kappa-Poincare symmetries are linked to Chern-Simons theory only in the de
Sitter case, and the relevant Chern-Simons theory is physically inequivalent to
(2+1)-gravity.


title: A Radio Survey of Seven Southern X-ray Luminous Clusters of Galaxies

abstract:
  The Australia Telescope Compact Array (ATCA) has been used at 1.38 and 2.38
GHz to survey seven southern Abell clusters of galaxies with high X-ray
luminosities: A2746, A2837, A3126, A3216, A3230, A3827 and A3836. The clusters
have also been surveyed at 0.843 GHz with the Molonglo Observatory Synthesis
Telescope (MOST). We have listed a complete 1.38-GHz sample of 149 radio
sources within the Abell circles centred on their X-ray centroids. We compare
their identification fractions, emitted 1.38-GHz and optical powers, radio
spectral indices and radial variation in projected source density with those of
the radio-selected samples of Slee et al. (1998). We compare our fractional
radio luminosity function with that of the radio-selected samples of Ledlow and
Owen (1996) and Slee et al. (1998). Three significant differences are noted
between X-ray and radio-selected samples of clusters; (1) the X-ray sample has
an excess of flat-spectrum radio sources; (2) the fractional radio luminosity
function for the FR I sources in the X-ray selected sample is much steeper,
implying that fewer of their cluster galaxies become hosts for the stronger FR
I radio galaxies; (3) a complete absence of FR II radio galaxies in the X-ray
selected sample. The average excess projected density of radio sources near our
cluster centres is approx. 5 times the background source density.


title:
Phase locking of two independent degenerate coherent anti-Stokes Raman
  scattering processes

abstract:
  We propose an elegant scheme towards phase locking of two independent
degenerate coherent anti-Stokes Raman scattering (CARS) processes. The optical
implementation involves a modified Mach-Zehnder interferometer that is utilized
to transfer phase coherence from three totally uncorrelated laser beams into
two degenerate CARS beams which are independently produced in two distinct
Raman active samples. Such a phase-transport interferometer allows for explicit
measurement and control of phase differences between the two phase-locked
degenerate CARS processes, hence may lead to applications in other pertinent
research fields.


title:
Comment on "Sizes and relative geoeffectiveness of interplanetary
  coronal mass ejections and the preceding shock sheaths during intense storms
  in 1996-2005" by J. Zhang et al

abstract:
  Recently Zhang et al. [2008] presented a statistical study of sizes and
relative geoeffectiveness of ICMEs (bodies of magnetic clouds) and preceding
sheaths for 46 events responsible for intense (Dst < -100 nT) geomagnetic
storms in 1996-2005 in which only a single ICME was responsible for generating
the storm. Here we would like to comment several results and conclusions of
this paper.


title:
Binding between endohedral Na atoms in Si clathrate I; a first
  principles study

abstract:
  We investigate the binding nature of the endohedral sodium atoms with the
ensity functional theory methods, presuming that the clathrate I consists of a
sheaf of one-dimensional connections of Na@Si$_{24}$ cages interleaved in three
perpendicular directions. Each sodium atom loses 30% of the 3s$^1$ charge to
the frame, forming an ionic bond with the cage atoms; the rest of the electron
contributes to the covalent bond between the nearest Na atoms. The presumption
is proved to be valid; the configuration of the two Na atoms in the nearest
Si$_{24}$ cages is more stable by 0.189 eV than that in the Si$_{20}$ and
Si$_{24}$ cages. The energy of the beads of the two distorted Na atoms is more
stable by 0.104 eV than that of the two infinitely separated Na atoms. The
covalent bond explains both the preferential occupancies in the Si$_{24}$ cages
and the low anisotropic displacement parameters of the endohedral atoms in the
Si$_{24}$ cages in the [100] directions of the clathrate I.


title: Cosmological Models and Latest Observational Data

abstract:
  In this note, we consider the observational constraints on some cosmological
models by using the 307 Union type Ia supernovae (SNIa), the 32 calibrated
Gamma-Ray Bursts (GRBs) at $z>1.4$, the updated shift parameter $R$ from WMAP
5-year data (WMAP5), and the distance parameter $A$ of the measurement of the
baryon acoustic oscillation (BAO) peak in the distribution of SDSS luminous red
galaxies with the updated scalar spectral index $n_s$ from WMAP5. The tighter
constraints obtained here update the ones obtained previously in the
literature.


title:
Weil-Petersson geometry for families of hyperbolic conical Riemann
  Surfaces

abstract:
  We study the Weil-Petersson geometry for holomorphic families of Riemann
Surfaces equipped with the unique conical metric of constant curvature -1.


title:
Assessment of the RE(OH)3 Ising-like Magnetic Materials as Possible
  Candidates for the Study of Transverse-Field-Induced Quantum Phase
  Transitions

abstract:
  The LiHo$_x$Y$_{1-x}$F$_4$ Ising magnetic material subject to a magnetic
field, $B_x$, perpendicular to the Ho$^{3+}$ Ising direction has shown over the
past twenty years to be a host of very interesting thermodynamic and magnetic
phenomena. Unfortunately, the availability of other magnetic materials other
than LiHo$_x$Y$_{1-x}$F$_4$ that may be described by a transverse field Ising
model remains very much limited. It is in this context that we use here
mean-field theory to investigate the suitability of the Ho(OH)$_{3}$,
Dy(OH)$_{3}$ and Tb(OH)$_3$ insulating hexagonal dipolar Ising-like
ferromagnets for the study of the quantum phase transition induced by a
magnetic field, $B_x$, applied perpendicular to the Ising spin direction. From
our calculations we estimate the critical transverse field, $B_{x}^{c}$, to
destroy ferromagnetic order at zero temperature to be $B_{x}^{c}=$4.35 T,
$B_{x}^{c}=$5.03 T and $B_{x}^{c}=$54.81 T for Ho(OH)$_{3}$, Dy(OH)$_{3}$ and
Tb(OH)$_{3}$, respectively. We conclude from our calculations that Ho(OH)$_{3}$
and Dy(OH)$_{3}$, and their Y$^{3+}$ diamagnetically diluted variants,
Ho$_{x}$Y$_{1-x}$(OH)$_{3}$ and Dy$_{x}$Y$_{1-x}$(OH)$_{3}$, are potentially
interesting systems to study transverse-field induced quantum fluctuations
effects in hard axis (Ising-like) magnetic materials.


title: Model Checking Probabilistic Timed Automata with One or Two Clocks

abstract:
  Probabilistic timed automata are an extension of timed automata with discrete
probability distributions. We consider model-checking algorithms for the
subclasses of probabilistic timed automata which have one or two clocks.
Firstly, we show that PCTL probabilistic model-checking problems (such as
determining whether a set of target states can be reached with probability at
least 0.99 regardless of how nondeterminism is resolved) are PTIME-complete for
one-clock probabilistic timed automata, and are EXPTIME-complete for
probabilistic timed automata with two clocks. Secondly, we show that, for
one-clock probabilistic timed automata, the model-checking problem for the
probabilistic timed temporal logic PCTL is EXPTIME-complete. However, the
model-checking problem for the subclass of PCTL which does not permit both
punctual timing bounds, which require the occurrence of an event at an exact
time point, and comparisons with probability bounds other than 0 or 1, is
PTIME-complete for one-clock probabilistic timed automata.


title: Ultracold Molecules in the Ro-Vibrational Triplet Ground State

abstract:
  We report here on the production of an ultracold gas of tightly bound Rb2
molecules in the ro-vibrational triplet ground state, close to quantum
degeneracy. This is achieved by optically transferring weakly bound Rb2
molecules to the absolute lowest level of the ground triplet potential with a
transfer efficiency of about 90%. The transfer takes place in a 3D optical
lattice which traps a sizeable fraction of the tightly bound molecules with a
lifetime exceeding 200 ms.


title:
The Stochastic Logarithmic Norm for Stability Analysis of Stochastic
  Differential Equations

abstract:
  To analyze the stability of It\^o stochastic differential equations with
multiplicative noise, we introduce the stochastic logarithmic norm. The
logarithmic norm was originally introduced by G. Dahlquist in 1958 as a tool to
study the growth of solutions to ordinary differential equations and for
estimating the error growth in discretization methods for their approximate
solutions. We extend the concept to the stability analysis of It\^o stochastic
differential equations with multiplicative noise. Stability estimates for
linear It\^o SDEs using the one, two and $\infty$-norms in the $l$-th mean,
where $1 \leq l < \infty $, are derived and the application of the stochastic
logarithmic norm is illustrated with examples.


title:
Simultaneous Modular Reduction and Kronecker Substitution for Small
  Finite Fields

abstract:
  We present algorithms to perform modular polynomial multiplication or modular
dot product efficiently in a single machine word. We pack polynomials into
integers and perform several modular operations with machine integer or
floating point arithmetic. The modular polynomials are converted into integers
using Kronecker substitution (evaluation at a sufficiently large integer). With
some control on the sizes and degrees, arithmetic operations on the polynomials
can be performed directly with machine integers or floating point numbers and
the number of conversions can be reduced. We also present efficient ways to
recover the modular values of the coefficients. This leads to practical gains
of quite large constant factors for polynomial multiplication, prime field
linear algebra and small extension field arithmetic.


title: Weak convergence of the regularization path in penalized M-estimation

abstract:
  We consider an estimator $\hbbeta_n(t)$ defined as the element
$\bphi\in\bPhi$ minimizing a contrast process $\pencontrast(\bphi, t)$ for each
t. We give some general results for deriving the weak convergence of
$\sqrt{n}(\hbbeta_n-\bbeta)$ in the space of bounded functions, where, for each
t, $\bbeta(t)$ is the $\bphi\in\bPhi$ minimizing the limit of
$\pencontrast(\bphi, t)$ as $n\to\infty$. These results are applied in the
context of penalized M-estimation, that is, when $\pencontrast(\bphi,
t)=M_n(\bphi)+ t J_n(\bphi)$, where $M_n$ is a usual contrast process and $J_n$
a penalty such as the $\ell^1$ norm or the squared $\ell^2$ norm. The function
$\hbbeta_n$ is then called a \emph{regularization path}. For instance we show
that the central limit theorem established for the lasso estimator in Knight
and Fu (2000) continues to hold in a functional sense for the regularization
path. Other examples include various possible contrast processes for $M_n$ such
as those considered in Pollard (1985).