title:
Radiation Hydrodynamics in Kerr Spacetime: Equations without Coordinate
  Singularity at the Event Horizon

abstract:
  Equations of fully general relativistic radiation hydrodynamics around a
rotating black hole are derived by using the Kerr-Schild coordinate where there
is no coordinate singularity at the event horizon. Since the radiation
interacts with matter moving with relativistic velocities near the event
horizon, the interplay between the radiation and the matter should be described
fully relativistically. In the formalism used in this study, while the
interactions between matter and radiation are introduced in the comoving frame,
the equations and the equations and the derivatives for the description of the
global evolution of both matter and the radiation are given in the Kerr-Schild
frame (KSF) which is a frame fixed to the coordinate describing the central
black hole. As a frame fixed to the coordinate, we use the locally non-rotating
reference frame (LNRF) representing a radially falling frame when the
Kerr-Schild coordinate is used. Around the rotating black hole, both the matter
and the radiation are affected by the frame-dragging effects.


title: Circumventing the No-Go Theorem in Noncommutative Gauge Field Theory

abstract:
  Stringent restrictions for model building are imposed by a no-go theorem in
noncommutative gauge field theory. Circumventing this theorem is crucial for
the construction of realistic models of particle interactions. To this end, the
noncommutative construction of tensor representations of gauge groups using
half-infinite Wilson lines is extended to allow for gauge groups consisting of
an arbitrary number of $U_*(N)$ factors. This as well allows representations
other than the ones permitted by the no-go theorem.


title: Coxeter Groups, Wavelets, Multiresolution and Sampling

abstract:
  In this short note we discuss the interplay between finite Coxeter groups and
construction of wavelet sets, generalized multiresolution analysis and
sampling.


title: Remarks Concerning Lubotzky's Filtration

abstract:
  A discrete group which admits a faithful, finite dimensional, linear
representation over a field $\mathbb F$ of characteristic zero is called
linear. This note combines the natural structure of semi-direct products with
work of A. Lubotzky on the existence of linear representations to develop a
technique to give sufficient conditions to show that a semi-direct product is
linear.
  Let $G$ denote a discrete group which is a semi-direct product given by a
split extension $1 \to \pi \to G \to \Gamma \to 1$. This note defines an
additional type of structure for this semi-direct product called a stable
extension below. The main results are as follows:
  1. If $\pi$ and $\Gamma$ are linear, and the extension is stable, then $G$ is
also linear. Restrictions concerning this extension are necessary to guarantee
that $G$ is linear as seen from properties of the Formanek-Procesi "poison
group". 2. If the action of $\Gamma$ on $\pi$ has a "Galois-like" property that
it factors through the automorphisms of certain natural "towers of groups over
$\pi$" (to be defined below), then the associated extension is stable and thus
$G$ is linear. 3. The condition of a stable extension also implies that $G$
admits filtration quotients which themselves give a natural structure of Lie
algebra and which also imply earlier results of Kohno, and Falk-Randell on the
Lie algebra attached to the descending central series associated to the
fundamental groups of complex hyperplane complements.
  The methods here suggest that a possible technique for obtaining new
linearity results may be to analyze automorphisms of towers of groups.


title: Realization of two Fourier-limited solid-state single-photon sources

abstract:
  We demonstrate two solid-state sources of indistinguishable single photons.
High resolution laser spectroscopy and optical microscopy were combined at T =
1.4 K to identify individual molecules in two independent microscopes. The
Stark effect was exploited to shift the transition frequency of a given
molecule and thus obtain single photon sources with perfect spectral overlap.
Our experimental arrangement sets the ground for the realization of various
quantum interference and information processing experiments.


title: Pulsar High-Energy Emission From the Polar Cap and Slot Gap

abstract:
  Forty years after the discovery of rotation-powered pulsars, we still do not
understand many aspects of their pulsed emission. In the last few years there
have been some fundamental developments in acceleration and emission models. I
will review both the basic physics of the models as well as the latest
developments in understanding the high-energy emission of rotation-powered
pulsars, with particular emphasis on the polar-cap and slot-gap models. Special
and general relativistic effects play important roles in pulsar emission, from
inertial frame-dragging near the stellar surface to aberration, time-of-flight
and retardation of the magnetic field near the light cylinder. Understanding
how these effects determine what we observe at different wavelengths is
critical to unraveling the emission physics. I will discuss how current and
future X-ray and gamma-ray detectors can test the predictions of these models.


title:
HESS J1023-575: Non-thermal particle acceleration associated with the
  young stellar cluster Westerlund 2

abstract:
  The results from H.E.S.S. observations towards Westerlund 2 are presented.
The detection of very-high-energy gamma-ray emission towards the young stellar
cluster Westerlund 2 in the HII complex RCW49 by H.E.S.S. provides ample
evidence that particle acceleration to extreme energies is associated with this
region. A variety of possible emission scenarios is mentioned, ranging from
high-energy gamma-ray production in the colliding wind zone of the massive
Wolf-Rayet binary WR20a, collective wind scenarios, diffusive shock
acceleration at the boundaries of wind-blown bubbles in the stellar cluster,
and outbreak phenomena from hot stellar winds into the interstellar medium.
These scenarios are briefly compared to the characteristics of the associated
new VHE gamma-ray source HESS J1023-575, and conclusions on the validity of the
respective emission scenarios for high-energy gamma-ray production in the
Westerlund 2 system are drawn.


title: P-matrix recognition is co-NP-complete

abstract:
  This is a summary of the proof by G.E. Coxson that P-matrix recognition is
co-NP-complete. The result follows by a reduction from the MAX CUT problem
using results of S. Poljak and J. Rohn.


title: Three-way tiling sets in two dimensions

abstract:
  In this article we show that there exist measurable sets W in the plane with
finite measure that tile the plane in a measurable way under the action of a
expansive matrix A, an affine Weyl group W, and a full rank lattice G. This
note is follow-up research to the earlier article "Coxeter groups and wavelet
sets" by the first and second authors, and is also relevant to the earlier
article "Coxeter groups, wavelets, multiresolution and sampling" by M. Dobrescu
and the third author. After writing these two articles, the three authors
participated in a workshop at the Banff Center on "Operator methods in fractal
analysis, wavelets and dynamical systems," December 2 -- 7, 2006, organized by
O. Bratteli, P. Jorgensen, D. Kribs, G. Olafsson, and S. Silvestrov, and
discussed the interrelationships and differences between the articles, and
worked on two open problems posed in the Larson-Massopust article. We solved
part of Problem 2, including a surprising positive solution to a conjecture
that was raised, and we present our results in this article.


title: $C^*-$crossed product of groupoid actions on categories

abstract:
  Suppose that $G$ is a groupoid acting on a small category $H$ in the sense of
\cite[Definition 4]{NOT} and $H\times_\alpha G$ is the resulting semi-direct
product category (as in \cite[Proposition 8]{NOT}). We show that there exists a
subcategory $H_r \subseteq H$ satisfying some nice property called
``regularity'' such that $H_r \times_\alpha G = H\times_\alpha G$. Moreover, we
show that there exists a so-called ``quasi action'' (see Definition
\ref{quasi}) $\beta$ of $G$ on $C^*(H_r)$ (where $C^*(H_r)$ is the semigroupoid
$C^*$-algebra as defined in \cite{EXE}) such that $C^*(H_r\times_\alpha G) =
C^*(H_r)\times_\beta G$ (where the crossed product for $\beta$ is as defined in
Definition \ref{cross}).


title: K-string tensions at finite temperature and integrable models

abstract:
  It has recently been pointed out that simple scaling properties of Polyakov
correlation functions of gauge systems in the confining phase suggest that the
ratios of k-string tensions in the low temperature region is constant up to
terms of order T^3. Here we argue that, at least in a three-dimensional Z_4
gauge model, the above ratios are constant in the whole confining phase. This
result is obtained by combining numerical experiments with known exact results
on the mass spectrum of an integrable two-dimensional spin model describing the
infrared behaviour of the gauge system near the deconfining transition.


title: A combinatorial framework for RNA tertiary interaction

abstract:
  In this paper we show how to express RNA tertiary interactions via the
concepts of tangled diagrams. Tangled diagrams allow to formulate RNA base
triples and pseudoknot-interactions and to control the maximum number of
mutually crossing arcs. In particular we study two subsets of tangled diagrams:
3-noncrossing tangled-diagrams with $\ell$ vertices of degree two and
2-regular, 3-noncrossing partitions (i.e. without arcs of the form $(i,i+1)$).
Our main result is an asymptotic formula for the number of 2-regular,
3-noncrossing partitions, denoted by $p_{3,2}(n)$, 3-noncrossing partitions
over $[n]$. The asymptotic formula is derived by the analytic theory of
singular difference equations due to Birkhoff-Trjitzinsky. Explicitly, we prove
the formula $p_{3,2}(n+1)\sim K 8^{n}n^{-7}(1+c_{1}/n+c_{2}/n^2+c_3/n^3)$ where
$K,c_i$, $i=1,2,3$ are constants.


title: Construction of potentials using mixed scattering data

abstract:
  The long-standing problem of constructing a potential from mixed scattering
data is discussed. We first consider the fixed-$\ell$ inverse scattering
problem. We show that the zeros of the regular solution of the Schr\"odinger
equation, $r_{n}(E)$ which are monotonic functions of the energy, determine a
unique potential when the domain of energy is such that the $r_{n}(E)$'s range
from zero to infinity. The latter method is applied to the domain $\{E \geq
E_0, \ell=\ell_0 \} \cup \{E=E_0, \ell \geq \ell_0 \}$ for which the zeros of
the regular solution are monotonic in both parts of the domain and still range
from zero to infinity. Our analysis suggests that a unique potential can be
obtained from the mixed scattering data $\{\delta(\ell_0,k), k \geq k_0 \} \cup
\{\delta(\ell,k_0), \ell \geq \ell_0 \}$ provided that certain integrability
conditions required for the fixed $\ell$-problem, are fulfilled. The uniqueness
is demonstrated using the JWKB approximation.


title: Radiative B-L symmetry breaking in supersymmetric models

abstract:
  We propose a scheme where the three relevant physics scales related to the
supersymmetry, electroweak, and baryon minus lepton (B-L) breakings are linked
together and occur at the TeV scale. The phenomenological implications in the
Higgs and leptonic sectors are discussed.


title: Clumping effects on non-thermal particle spectra in massive star systems

abstract:
  Observational evidence exists that winds of massive stars are clumped. Many
massive star systems are known as non-thermal particle production sites, as
indicated by their synchrotron emission in the radio band. As a consequence
they are also considered as candidate sites for non-thermal high-energy photon
production up to gamma-ray energies. The present work considers the effects of
wind clumpiness expected on the emitting relativistic particle spectrum in
colliding wind systems, built up from the pool of thermal wind particles
through diffusive particle acceleration, and taking into account inverse
Compton and synchrotron losses. In comparison to a homogeneous wind, a clumpy
wind causes flux variations of the emitting particle spectrum when the clump
enters the wind collision region. It is found that the spectral features
associated with this variability moves temporally from low to high energy bands
with the time shift between any two spectral bands being dependent on clump
size, filling factor, and the energy-dependence of particle energy gains and
losses.


title: Toward theory of quantum Hall effect in graphene

abstract:
  We analyze a gap equation for the propagator of Dirac quasiparticles and
conclude that in graphene in a magnetic field, the order parameters connected
with the quantum Hall ferromagnetism dynamics and those connected with the
magnetic catalysis dynamics necessarily coexist (the latter have the form of
Dirac masses and correspond to excitonic condensates). This feature of graphene
could lead to important consequences, in particular, for the existence of
gapless edge states. Solutions of the gap equation corresponding to recently
experimentally discovered novel plateaus in graphene in strong magnetic fields
are described.


title: The H.E.S.S. survey of the inner Galactic plane

abstract:
  The High Energy Stereoscopic System (H.E.S.S.), located in the Khomas
Highlands of Namibia, is an array of four imaging atmospheric-Cherenkov
telescopes designed to detect gamma-rays in the very high energy (VHE; > 100
GeV) domain. Its high sensitivity and large field-of-view (5 deg) make it an
ideal instrument to perform a survey within the Galactic plane for new VHE
sources. Previous observations in 2004/2005 resulted in numerous detections of
VHE gamma-ray emitters in the region l = 330 deg - 30 deg Galactic longitude.
Recently the survey was extended, covering the regions l = 280 deg - 330 deg
and l = 30 deg - 60 deg, leading to the discovery of several previously unknown
sources with high statistical significance. The current status of the survey
will be presented.


title: Scalable experimental estimation of multipartite entanglement

abstract:
  We present an efficient experimental estimation of the multipartite
entanglement of mixed quantum states in terms of simple parity measurements.


title:
Clustering Properties of restframe UV selected galaxies I: the
  correlation length derived from GALEX data in the local Universe

abstract:
  We present the first measurements of the angular correlation function of
galaxies selected in the far (1530 A) and near (2310 A) Ultraviolet from the
GALEX survey fields overlapping SDSS DR5 in low galactic extinction regions.
The area used covers 120 sqdeg (GALEX - MIS) down to magnitude AB = 22,
yielding a total of 100,000 galaxies. The mean correlation length is ~ 3.7 \pm
0.6 Mpc and no significant trend is seen for this value as a function of the
limiting apparent magnitude or between the GALEX bands. This estimate is close
to that found from samples of blue galaxies in the local universe selected in
the visible, and similar to that derived at z ~ 3 for LBGs with similar rest
frame selection criteria. This result supports models that predict anti-biasing
of star forming galaxies at low redshift, and brings an additional clue to the
downsizing of star formation at z<1.


title:
$n$-blocks collections on Fano manifolds and sheaves with regularity
  $-\infty$

abstract:
  Let $X$ be a smooth Fano manifold equipped with a `` nice '' $n$-blocks
collection in the sense of \cite{cm2} and $\mathcal {F}$ a coherent sheaf on
$X$. Assume that $X$ is Fano and that all blocks are coherent sheaves. Here we
prove that $\mathcal {F}$ has regularity $-\infty$ in the sense of \cite{cm2}
if ${Supp}(\mathcal {F})$ is finite, the converse being true under mild
assumptions. The corresponding result is also true when $X$ has a geometric
collection in the sense of \cite{cm1}.


title:
Importance of Metastable States in the Free Energy Landscapes of
  Polypeptide Chains

abstract:
  We show that the interplay between excluded volume effects, hydrophobicity,
and hydrogen bonding of a tube-like representation of a polypeptide chain gives
rise to free energy landscapes that exhibit a small number of metastable minima
corresponding to common structural motifs observed in proteins. The complexity
of the landscape increases only moderately with the length of the chain.
Analysis of the temperature dependence of these landscapes reveals that the
stability of specific metastable states is maximal at a temperature close to
the mid-point of folding. These mestastable states are therefore likely to be
of particular significance in determining the generic tendency of proteins to
aggregate into potentially pathogenic agents.


title:
Mechanism of Ambipolar Field-Effect Transistors on One-Dimensional
  Organic Mott Insulators

abstract:
  The experimentally observed, ambipolar field-effect characteristics of Mott
insulators are reproduced in the one-dimensional Hubbard model attached to a
tight-binding model for source and drain electrodes. The formation of Schottky
barriers, originating from the work-function difference, is taken into account
by a potential satisfying the Poisson equation with an appropriate boundary
condition. Then, these field-effect characteristics are shown to be related by
unique current-voltage characteristics of metal-Mott-insulator interfaces.


title:
Influence of stellar X-ray luminosity distribution and its evolution on
  exoplanetary mass loss

abstract:
  Aims: We investigate the influence of high-energy stellar radiation at
close-in orbits on atmospheric mass loss during stellar evolution of a G-type
star. Methods: High-energy stellar luminosity varies over a wide range for G
field stars. The temporal evolution of the distribution of stellar X-ray
luminosity and its influence on the evolution of close-in exoplanets is
investigated. X-ray luminosity distributions from the Pleiades, the Hyades and
the field are used to derive a scaling law for the evolution of the stellar
X-ray luminosity distribution. A modified energy-limited escape approach is
used to calculate atmospheric mass loss for a broad range of planetary
parameters. Results: We show that the evolution of close-in exoplanets strongly
depends on the detailed X-ray luminosity history of their host stars, which
varies over several orders-of-magnitude for G stars. Stars located at the
high-energy tail of the luminosity distribution can evaporate most of its
planets within 0.5 AU, while for a moderate luminosity a significant fraction
of planets can survive. We show the change on an initial planetary mass
distribution caused by atmospheric escape.


title: JANUS: an FPGA-based System for High Performance Scientific Computing

abstract:
  This paper describes JANUS, a modular massively parallel and reconfigurable
FPGA-based computing system. Each JANUS module has a computational core and a
host. The computational core is a 4x4 array of FPGA-based processing elements
with nearest-neighbor data links. Processors are also directly connected to an
I/O node attached to the JANUS host, a conventional PC. JANUS is tailored for,
but not limited to, the requirements of a class of hard scientific applications
characterized by regular code structure, unconventional data manipulation
instructions and not too large data-base size. We discuss the architecture of
this configurable machine, and focus on its use on Monte Carlo simulations of
statistical mechanics. On this class of application JANUS achieves impressive
performances: in some cases one JANUS processing element outperfoms high-end
PCs by a factor ~ 1000. We also discuss the role of JANUS on other classes of
scientific applications.


title:
Common Beliefs and Public Announcements in Strategic Games with
  Arbitrary Strategy Sets

abstract:
  We provide an epistemic analysis of arbitrary strategic games based on
possibility correspondences. We first establish a generic result that links
true common beliefs (and, respectively, common knowledge) of players'
rationality defined by means of `monotonic' properties, with the iterated
elimination of strategies that do not satisfy these properties. It allows us to
deduce the customary results concerned with true common beliefs of rationality
and iterated elimination of strictly dominated strategies as simple
corollaries. This approach relies on Tarski's Fixpoint Theorem. We also provide
an axiomatic presentation of this generic result. This allows us to clarify the
proof-theoretic principles assumed in players' reasoning. Finally, we provide
an alternative characterization of the iterated elimination of strategies based
on the concept of a public announcement. It applies to `global properties'.
Both classes of properties include the notions of rationalizability and the
iterated elimination of strictly dominated strategies.


title: Two-pion-exchange effects in the $pp\to pp\pi^0$ reaction

abstract:
  We study the pp \to pp\pi^0 reaction near threshold based on heavy-baryon
chiral perturbation theory. We show that the two-pion-exchange diagrams give
much larger contribution than the one-pion-exchange diagram which is of lower
chiral order in Weinberg's counting scheme. We also discuss the relation of our
results to the momentum counting scheme.


title: Classical and new loglog-theorems

abstract:
  We present integral variants of results due to Carleman, Wolf, Levinson,
Sjoberg, and Matsaev on majorants of analytic functions. Main ingredient is a
complete description for radial projections of harmonic measures of strictly
star-shaped domains in the plane.


title:
Dynamics, dephasing and clustering of impurity atoms in Bose-Einstein
  condensates

abstract:
  We investigate the influence of a Bose-Einstein condensate (BEC) on the
properties of immersed impurity atoms, which are trapped in an optical lattice.
Assuming a weak coupling of the impurity atoms to the BEC, we derive a quantum
master equation for the lattice system. In the special case of fixed impurities
with two internal states the atoms represent a quantum register and the quantum
master equation reproduces the exact evolution of the qubits. We characterise
the qubit dephasing which is caused by the interspecies coupling and show that
the effect of sub- and superdecoherence is observable for realistic
experimental parameters. Furthermore, the BEC phonons mediate an attractive
interaction between the impurities, which has an important impact on their
spatial distribution. If the lattice atoms are allowed to move, there occurs a
sharp transition with the impurities aggregating in a macroscopic cluster at
experimentally achievable temperatures. We also investigate the impact of the
BEC on the transport properties of the impurity atoms and show that a crossover
from coherent to diffusive behaviour occurs with increasing interaction
strength.


title: N=2 supersymmetric spin foams in three dimensions

abstract:
  We construct the spin foam model for N=2 supergravity in three dimensions.
Classically, it is a BF theory with gauge algebra osp(2|2). This algebra has
representations which are not completely reducible. This complicates the
procedure when building a state sum. Fortunately, one can and should excise
these representations. We show that the restricted subset of representations
form a subcategory closed under tensor product. The resulting state-sum is once
again a topological invariant. Furthermore, within this framework one can
identify positively and negatively charged fermions propagating on the spin
foam. These results on osp(2|2) representations and intertwiners apply more
generally to spin network states for N=2 loop quantum supergravity (in 3+1
dimensions) where it allows to define a notion of BPS states.


title: Dynamical parallax of sigma Ori AB: mass, distance and age

abstract:
  The massive OB-type binary sigma Ori AB is in the centre of the very young
sigma Orionis cluster. I have computed the most probable distances and masses
of the binary for several ages using a dynamical parallax-like method. It
incorporates the BVRIH-band apparent magnitudes of both components, precise
orbital parameters, interstellar extinction and a widely used grid of stellar
models from the literature, the Kepler's third law and a chi^2 minimisation.
The derived distance is 334^(+25)_(-22) pc for an age of 3+/-2 Ma; larger ages
and distances are unlikely. The masses of the primary and the secondary lie on
the approximate intervals 16-20 and 10-12 Msol, respectively. I also discuss
the possibility of sigma Ori AB being a triple system at ~385 pc. These results
will help to constrain the properties of young stars and substellar objects in
the sigma Orionis cluster.


title:
Transport and percolation in a low-density high-mobility two-dimensional
  hole system

abstract:
  We present a study of the temperature and density dependence of the
resistivity of an extremely high quality two-dimensional hole system grown on
the (100) surface of GaAs. For high densities in the metallic regime ($p\agt 4
\times 10^{9}$ cm$^{-2}$), the nonmonotonic temperature dependence ($\sim
50-300$ mK) of the resistivity is consistent with temperature dependent
screening of residual impurities. At a fixed temperature of $T$= 50 mK, the
conductivity vs. density data indicates an inhomogeneity driven
percolation-type transition to an insulating state at a critical density of
$3.8\times 10^9$ cm$^{-2}$.


title: The significance of numerical coincidences in nature

abstract:
  This is the first part of a survey whose ultimate purpose is to clarify the
significance of the famous coincidence between the Hubble age of the universe
and a certain combination of microphysical parameters. In this part the way is
prepared by a discussion of the manner in which familiar local phenomena depend
qualitatively, and in order of magnitude, quantitatively on the fundamental
parameters of microphysics. In order to keep the account concise while
remaining self contained, only the barest essentials of the standard nuclear
physical and astrophysical calculations involved are given. Only six of the
fundamental parameters play a dominant part, namely the coupling constants of
the strong, electromagnetic, and gravitational forces, and the mass ratios of
the proton, neutron, electron and pi-meson. Attention is drawn to the important
consequences of three coincidental relationships between these parameters. It
is shown that most of the principle limiting masses of astrophysics arise (in
fundamental units) simply as the reciprocal of the gravitational fine structure
constant, with relatively small adjustment factors. The dividing point between
red dwarf and blue giant stars turns out to be an exception: this division
occurs within the range of the main sequence stars only as a consequence of the
rather exotic coincidence that the ninth power of the electromagnetic fine
structure constant is roughly equal to the square root of the gravitational
fine structure constant.


title:
Wigner functions, Fresnel optics, and symplectic connections on phase
  space

abstract:
  We prove that Wigner functions contain a symplectic connection. The latter
covariantises the symplectic exterior derivative on phase space. We analyse the
role played by this connection and introduce the notion of local symplectic
covariance of quantum-mechanical states. This latter symmetry is at work in the
Schroedinger equation on phase space.


title: Search for Dark Matter Annihilation in Draco with STACEE

abstract:
  For some time, the Draco dwarf spheroidal galaxy has garnered interest as a
possible source for the indirect detection of dark matter. Its large
mass-to-light ratio and relative proximity to the Earth provide favorable
conditions for the production of detectable gamma rays from dark matter
self-annihilation in its core. The Solar Tower Atmospheric Cherenkov Effect
Experiment (STACEE) is an air-shower Cherenkov telescope located in
Albuquerque, NM capable of detecting gamma rays at energies above 100 GeV. We
present the results of the STACEE observations of Draco during the 2005-2006
observing season totaling 10 hours of livetime after cuts.


title: OCHA and the swiss-cheese operad

abstract:
  In this paper we show that the relation between Kajiura-Stasheff's OCHA and
A. Voronov's swiss-cheese operad is analogous to the relation between SH Lie
algebras and the little discs operad. More precisely, we show that the OCHA
operad is quasi-isomorphic to the operad of top-dimensional homology classes of
the swiss-cheese operad.


title: Quantum Noise, Scaling and Domain Formation in a Spinor BEC

abstract:
  In this paper we discuss Bose-Einstein spinor condensates for F=1 atoms in
the context of 87Rb, as studied experimentally by the Stamper-Kurn group
[Sadler et al. Nature (2006)]. The dynamical quantum fluctuations of a sample
that starts as a condensate of N atoms in a pure F=1, m_F = 0 state are
described in analogy to the `two-mode squeezing' of quantum optics in terms of
an su(1,1) algebra. In this system the initial m_F=0 condensate acts as a
source (`pump') for the creation pairs of m_F =+1,-1 atoms. We show that even
though the system as a whole is described by a pure state with zero entropy,
the reduced density matrix for the m_F = +1 degree of freedom, obtained by
tracing out the m_F = -1,0 degrees of freedom, corresponds to a thermal state.
Furthermore, these quantum fluctuations of the initial dynamics of the system
provide the seeds for the formation of domains of ferromagnetically aligned
spins.


title:
Single and binary evolution of Population III stars and their supernovae
  light curves

abstract:
  We present stellar evolution calculations for Population III stars for both
single and binary star evolution. Our models include 10 Msun and 16.5 Msun
single stars and a 10 Msun model star that undergoes an episode of accretion
resulting in a final mass of 16.1 Msun. For comparison, we present the
evolution of a solar heavy element abundance model. We use the structure from
late stage evolution models to calculate simulated supernova light curves.
Light curve comparisons are made between accretion and non-accretion progenitor
models, and models for single star evolution of comparable masses. Where
possible, we make comparisons to previous works. Similar investigations have
been carried out, but primarily for solar or near solar heavy metal abundance
stars and not including both the evolution and supernovae explosions in one
work.


title:
Two-Qubit Hilbert-Schmidt Separability Functions and Probabilities for
  Full-Dimensional Even-Dyson-Index Scenarios

abstract:
  We extend the findings and analyses of our two recent studies (Phys. Rev. A,
75, 032326 [2007] and arXiv:0704.3723) by, first, obtaining numerical estimates
of the separability function based on the (Euclidean, flat) Hilbert-Schmidt
(HS) metric for the 27-dimensional convex set of quaternionic two-qubit
systems. The estimated function appears to be strongly consistent with our
previously-formulated Dyson-index (beta = 1, 2, 4) ansatz, dictating that the
quaternionic (beta=4) separability function should be exactly proportional to
the square of the separability function for the 15-dimensional convex set of
two-qubit complex (beta=2) systems, as well as the fourth power of the
separability function for the 9-dimensional convex set of two-qubit real
(beta=1) systems. In particular, we conclude that S_{quat}(mu) =(6/71)^2
((3-mu^2) mu)^4 =(S_{complex}(mu))^2. Here, mu =(rho_{11} rho_{44}/(rho_{22}
rho_{33})^(1/2), where rho is a 4 x 4 two-qubit density matrix. We can, thus,
supplement (and fortify) our previous assertion that the HS separability
probability of the two-qubit complex states is 8/33= 0.242424, by claiming that
its quaternionic counterpart is 72442944/936239725 = 0.0773765. We also comment
on and analyze the odd beta=1 and 3 cases.


title: Free frobenius algebra on the differential forms of a manifold

abstract:
  We construct an action of a free resolution of the Frobenius properad on the
differential forms of a closed oriented manifold. As a consequence, the forms
of a manifold with values in a semi-simple Lie algebra have an additional
structure given by an action of a free resolution of the properad describing
Lie di-algebras with module compatibility.


title: Rubber friction on (apparently) smooth lubricated surfaces

abstract:
  We study rubber sliding friction on hard lubricated surfaces. We show that
even if the hard surface appears smooth to the naked eye, it may exhibit short
wavelength roughness, which may give the dominant contribution to rubber
friction. That is, the observed sliding friction is mainly due to the
viscoelastic deformations of the rubber by the substrate surface asperities.
The presented results are of great importance for rubber sealing and other
rubber applications involving (apparently) smooth surfaces.


title: Testing Born-Infeld electrodynamics in waveguides

abstract:
  Waveguides can be employed to test non-linear effects in electrodynamics. We
solve Born-Infeld equations for TE waves in a rectangular waveguide. We show
that the energy velocity acquires a dependence on the amplitude, and harmonic
components appear as a consequence of the non-linear behavior.


title: Homotopical interpretation of globular complex by multipointed d-space

abstract:
  Globular complexes were introduced by E. Goubault and the author in
arXiv:math/0107060 to model higher dimensional automata. Globular complexes are
topological spaces equipped with a globular decomposition which is the directed
analogue of the cellular decomposition of a CW-complex. We prove that there
exists a combinatorial model category such that the cellular objects are
exactly the globular complexes and such that the homotopy category is
equivalent to the homotopy category of flows introduced in arXiv:math/0308054.
The underlying category of this model category is a variant of M. Grandis'
notion of d-space over a topological space colimit generated by simplices. This
result enables us to understand the relationship between the framework of flows
and other works in directed algebraic topology using d-spaces. It also enables
us to prove that the underlying homotopy type functor of flows constructed in
arXiv:math/0308063 can be interpreted up to equivalences of categories as the
total left derived functor of a left Quillen adjoint.


title:
Optimization of a Neutrino Factory: Discovery Machine versus Precision
  Instrument

abstract:
  We discuss the optimization of a neutrino factory experiment for the purpose
of sin^2(2theta_13), mass hierarchy, and CP violation discoveries. This
includes a review of possible optimization strategies, as well as an
application of these to different sin^2(2theta_13) regions.


title: H-> WZ and H->Wgamma in the MSSM

abstract:
  We study the complete one loop contribution to $H^\pm\to W^\pm Z$ and $H^\pm
\to W^\pm \gamma$ in the Minimal Supersymmetric Standard Model (MSSM).


title: Graphene Terahertz Plasmon Oscillators

abstract:
  In this paper we propose and discuss coherent terahertz sources based on
charge density wave (plasmon) amplification in two dimensional graphene. The
coupling of the plasmons to interband electron-hole transitions in population
inverted graphene layers can lead to plasmon amplification through stimulated
emission. Plasmon gain values in graphene can be very large due to the small
group velocity of the plasmons and the strong confinement of the plasmon field
in the vicinity of the graphene layer. We present a transmission line model for
plasmon propagation in graphene that includes plasmon dissipation and plasmon
interband gain due to stimulated emission. Using this model, we discuss design
for terahertz plasmon oscillators and derive the threshold condition for
oscillation taking into account internal losses and also losses due to external
coupling. The large gain values available at terahertz frequencies in graphene
can lead to integrated oscillators that have dimensions in the 1-10 micron
range.


title: Luminous Red Galaxies in hierarchical cosmologies

abstract:
  Luminous red galaxies (LRGs) are much rarer and more massive than L*
galaxies. Coupled with their extreme colours, LRGs therefore provide a
demanding testing ground for the physics of massive galaxy formation. We
present the first self-consistent predictions for the abundance and properties
of LRGs in hierarchical structure formation models. We test two published
models which use quite different mechanisms to suppress the formation of
massive galaxies: the Bower et al. (2006) model, which invokes ``AGN-feedback''
to prevent gas from cooling in massive haloes, and the Baugh et al. (2005)
model which relies upon a ``superwind'' to eject gas before it is turned into
stars. Without adjusting any parameters, the Bower et al. model gives an
excellent match to the observed luminosity function of LRGs in the SDSS (with a
median redshift of z=0.24) and to their clustering; the Baugh et al. model is
less successful in these respects. Both models fail to match the observed
abundance of LRGs at z=0.5 to better than a factor of ~2. In the models, LRGs
are typically bulge dominated systems with M* of ~2x10^11 h^{-1} M_sun and
velocity dispersions of ~250 km s^{-1}. Around half of the stellar mass in the
model LRGs is already formed by z~2.2 and is assembled into one main progenitor
by z~1.5; on average, only 25% of the mass of the main progenitor is added
after z~1. LRGs are predicted to be found in a wide range of halo masses, a
conclusion which relies on properly taking into account the scatter in the
formation histories of haloes. Remarkably, we find that the correlation
function of LRGs is predicted to be a power law down to small pair separations,
in excellent agreement with observational estimates. Neither the Bower et al.
nor the Baugh et al. model is able to reproduce the observed radii of LRGs.


title: Magnetic fields and the dynamics of spiral galaxies

abstract:
  We investigate the dynamics of magnetic fields in spiral galaxies by
performing 3D MHD simulations of galactic discs subject to a spiral potential.
Recent hydrodynamic simulations have demonstrated the formation of inter-arm
spurs as well as spiral arm molecular clouds provided the ISM model includes a
cold HI phase. We find that the main effect of adding a magnetic field to these
calculations is to inhibit the formation of structure in the disc. However,
provided a cold phase is included, spurs and spiral arm clumps are still
present if $\beta \gtrsim 0.1$ in the cold gas. A caveat to two phase
calculations though is that by assuming a uniform initial distribution, $\beta
\gtrsim 10$ in the warm gas, emphasizing that models with more consistent
initial conditions and thermodynamics are required. Our simulations with only
warm gas do not show such structure, irrespective of the magnetic field
strength. Furthermore, we find that the introduction of a cold HI phase
naturally produces the observed degree of disorder in the magnetic field, which
is again absent from simulations using only warm gas. Whilst the global
magnetic field follows the large scale gas flow, the magnetic field also
contains a substantial random component that is produced by the velocity
dispersion induced in the cold gas during the passage through a spiral shock.
Without any cold gas, the magnetic field in the warm phase remains relatively
well ordered apart from becoming compressed in the spiral shocks. Our results
provide a natural explanation for the observed high proportions of disordered
magnetic field in spiral galaxies and we thus predict that the relative
strengths of the random and ordered components of the magnetic field observed
in spiral galaxies will depend on the dynamics of spiral shocks.


title: Separation of Attractors in 1-modulus Quantum Corrected Special Geometry

abstract:
  We study the attractor equations for a quantum corrected prepotential
F=t^3+i\lambda, with \lambda \in R,which is the only correction which preserves
the axion shift symmetry and modifies the geometry.
  By performing computations in the ``magnetic'' charge configuration, we find
evidence for interesting phenomena (absent in the classical limit of vanishing
\lambda). For a certain range of the quantum parameter \lambda we find a
``separation'' of attractors, i.e. the existence of multiple solutions to the
Attractor Equations for fixed supporting charge configuration. Furthermore, we
find that, away from the classical limit, a ``transmutation'' of the
supersymmetry-preserving features of the attractors takes place when \lambda
reaches a particular critical value.


title: HE 0515-4414 - an unusual sub-damped Ly alpha system revisited

abstract:
  Using STIS and VLT UVES observations we have examined the ionization,
abundances, and differential dust depletion of metals, the kinematic structure,
and the physical conditions in the molecular hydrogen-bearing sub-damped Ly
alpha system toward HE 0515-4414 at z = 1.15. The velocity interval of
associated metal lines extends for 700 km/s. In addition, saturated H I
absorption is detected in the blue damping wing of the main component. The
column density ratios of associated Al II, Al III, and Fe II lines indicate
that the absorbing material is ionized. 19 of in total 31 detected metal line
components are formed within peripheral H II regions, while only 12 components
are associated with the predominantly neutral main absorber. For the main
absorber the observed abundance ratios of refractory elements to Zn range from
Galactic warm disk [Si/Zn] = - 0.40, [Fe/Zn] = -1.10 to halo-like and
essentially undepleted patterns. The dust-corrected metal abundances indicate a
nucleosynthetic odd-even effect and might imply an anomalous depletion of Si
relative to Fe for two components, but otherwise do correspond to solar ratios.
The intrinsic average metallicity is almost solar [Fe/H] = -0.08, whereas the
uncorrected average is [Zn/H] = -0.38. The ion abundances in the periphery
conform with solar element composition. The detection of H II as well as the
large variation in dust depletion for this sight line raises the question
whether in future studies of damped Ly alpha systems ionization and depletion
effects have to be considered in further detail. Ionization effects, for
instance, may pretend an enrichment of alpha elements. An empirical recipe for
detecting H II regions is provided.


title:
Stationary probability density of stochastic search processes in global
  optimization

abstract:
  A method for the construction of approximate analytical expressions for the
stationary marginal densities of general stochastic search processes is
proposed. By the marginal densities, regions of the search space that with high
probability contain the global optima can be readily defined. The density
estimation procedure involves a controlled number of linear operations, with a
computational cost per iteration that grows linearly with problem size.


title:
Neutrino induced threshold production of two pions and N^*(1440)
  electroweak form factors

abstract:
  We study the threshold production of two pions induced by neutrinos in
nucleon targets. The contribution of nucleon, pion and contact terms are
calculated using a chiral Lagrangian. The contribution of the Roper resonance,
neglected in earlier studies, has also been taken into account. The numerical
results for the cross sections are presented and compared with the available
experimental data. It has been found that in the two pion channels with
$\pi^+\pi^-$ and $\pi^0\pi^0$ in the final state, the contribution of the
$N^*(1440)$ is quite important and could be used to determine the $N^*(1440)$
electroweak transition form factors if experimental data with better statistics
become available in the future.


title: Langmuir wave filamentation instability

abstract:
  A Langmuir wave (LW) model is constructed whose equilibria are consistent
with stimulated Raman scatter optimization, with Hamiltonian dynamics and with
rotational invariance. Linear instability analysis includes terms to all orders
in wave amplitude and fluctuation wavenumber expansions, deltak. Resultant LW
modulational instability is nonstandard: as the LW amplitude increases,
unstable deltak range first expands and then shrinks to zero. Large amplitude
wave model dynamics requires hyper-diffraction terms if k LambdaD < 0.45, lest
artificially small length scales become unstable.


title: Some comments on embedding inflation in the AdS/CFT correspondence

abstract:
  The anti-de Sitter space/conformal field theory correspondence (AdS/CFT) can
potentially provide a complete formulation of string theory on a landscape of
stable and metastable vacua that naturally give rise to eternal inflation. As a
model for this process, we consider bubble solutions with de Sitter interiors,
obtained by patching together dS and Schwarzschild-AdS solutions along a bubble
wall. For an interesting subclass of these solutions the bubble wall reaches
spacelike infinity in the black hole interior. Including the effects of
perturbations leads to a null singularity emanating from this point. Such
solutions are interpreted as states in a single CFT, and are shown to be
compatible with holographic entropy bounds. The construction suggests de Sitter
entropy be interpreted as the total number of degrees of freedom in effective
field theory, with a novel adaptive stepsize cutoff.


title: Robustness of key features of loop quantum cosmology

abstract:
  Loop quantum cosmology of the k=0 FRW model (with a massless scalar field) is
shown to be exactly soluble if the scalar field is used as the internal time
already in the classical Hamiltonian theory. Analytical methods are then used
i) to show that the quantum bounce is generic; ii) to establish that the matter
density has an absolute upper bound which, furthermore, equals the critical
density that first emerged in numerical simulations and effective equations;
iii) to bring out the precise sense in which the Wheeler DeWitt theory
approximates loop quantum cosmology and the sense in which this approximation
fails; and iv) to show that discreteness underlying LQC is fundamental.
Finally, the model is compared to analogous discussions in the literature and
it is pointed out that some of their expectations do not survive a more careful
examination. An effort has been made to make the underlying structure
transparent also to those who are not familiar with details of loop quantum
gravity.


title: Markov Chain Methods For Analyzing Complex Transport Networks

abstract:
  We have developed a steady state theory of complex transport networks used to
model the flow of commodity, information, viruses, opinions, or traffic. Our
approach is based on the use of the Markov chains defined on the graph
representations of transport networks allowing for the effective network
design, network performance evaluation, embedding, partitioning, and network
fault tolerance analysis. Random walks embed graphs into Euclidean space in
which distances and angles acquire a clear statistical interpretation. Being
defined on the dual graph representations of transport networks random walks
describe the equilibrium configurations of not random commodity flows on
primary graphs. This theory unifies many network concepts into one framework
and can also be elegantly extended to describe networks represented by directed
graphs and multiple interacting networks.


title: Nonlinear NMR dynamics in hyperpolarized liquid 3He

abstract:
  In a highly polarized liquid (laser-polarized 3He-4He mixtures in our
experiment), dipolar magnetic interactions within the liquid introduce a
significant nonlinear and nonlocal contribution to the Bloch equation that
leads to instabilities during NMR evolution. We have launched a study of these
instabilities using spin echo techniques. At high magnetizations, a simple 180
degree rf pulse fails to refocus magnetization, so we use a standard
solid-state NMR pulse sequence: the magic sandwich. We report an experimental
and numerical investigation of the effect of this sequence on unstable NMR
evolution. Using a series of repeated magic sandwich sequences, the transverse
magnetization lifetime can be increased by up to three orders of magnitude.


title: A criterion for an abelian variety to be simple

abstract:
  In this note we give a numerical criterion that expresses the condition that
an abelian variety be simple in terms of an invariant that is closely related
to the s-invariant of Ein-Cutkosky-Lazarsfeld. The criterion yields new
examples where s-invariants are irrational. It may also be viewed as a
statement about the geometry of the ample cone.


title: On the Eisenstein ideal of Drinfeld modular curves

abstract:
  Let $\goth E(\goth p)$ denote the Eisenstein ideal in the Hecke algebra $\Bbb
T(\goth p)$ of the Drinfeld modular curve $X_0(\goth p)$ parameterizing
Drinfeld modules of rank two over $\Bbb F_q[T]$ of general characteristic with
Hecke level $\goth p$-structure, where $\goth p\triangleleft\Bbb F_q[T]$ is a
non-zero prime ideal. We prove that the characteristic $p$ of the field $\Bbb
F_q$ does not divide the order of the quotient $\Bbb T(\goth p)/\goth E(\goth
p)$ and the Eisenstein ideal $\goth E(\goth p)$ is locally principal.


title: Muntz type Theorems I

abstract:
  In this paper, we concentrate our attention on the Muntz problem in the
univariate setting and for the uniform norm.


title:
Group Theoretical Construction of Nucleon Operators using All-to-All
  Quark Propagators

abstract:
  We describe a method to construct irreducible baryon operators using
all-to-all quark propagators. It was demonstrated earlier that a large basis of
extended baryon operators on anisotropic, quenched lattices can be used to
reliably extract the masses of 5 or more excited states in the nucleon channel.
All-to-all quark propagators are expected to be needed when studying these
excited states on light, dynamical configurations because contributions from
multi-particle states are expected to be significant. The dilution method is
used to approximate the all-to-all quark propagators. Low-lying eigenmodes can
also be used if necessary. For efficient computation of matrix elements of the
interpolating operators, the algorithms should exploit the fact that many
extended baryon operators can be obtained from the different linear
combinations of three-quark colour-singlet operators. The sparseness of the
diluted noise vectors also afford several computation simplifications. Some
preliminary results are presented for nucleon effective masses.


title: Theory of semiconductor quantum-wire based single- and two-qubit gates

abstract:
  A GaAs/AlGaAs based two-qubit quantum device that allows the controlled
generation and straightforward detection of entanglement by measuring a
stationary current-voltage characteristic is proposed. We have developed a
two-particle Green's function method of open systems and calculate the
properties of three-dimensional interacting entangled systems
non-perturbatively. We present concrete device designs and detailed, charge
self-consistent predictions. One of the qubits is an all-electric Mach-Zehnder
interferometer that consists of two electrostatically defined quantum wires
with coupling windows, whereas the second qubit is an electrostatically defined
double quantum dot located in a second two-dimensional electron gas beneath the
quantum wires. We find that the entanglement of the device can be controlled
externally by tuning the tunneling coupling between the two quantum dots.


title: On the failure of the Poincar\'e Lemma for de-bar-sub-M II

abstract:
  We obtain very sharp results about the lack of validity of the Poincare lemma
for the tangential Cauchy Riemann equations, acting on tangential forms,
tangential to a CR manifold M of general CR dimension n, and general CR
codimension k. This generalizes the classical nonsolvability example of H.
Lewy. We also discuss the CR structure on the characteristic bundle to M, due
to certain degeneracies in the Levi form. A number of naturally geometrically
occuring examples are given.


title:
A graph theoretic expansion formula for cluster algebras of classical
  type

abstract:
  In this paper we give a graph theoretic combinatorial interpretation for the
cluster variables that arise in most cluster algebras of finite type. In
particular, we provide a family of graphs such that a weighted enumeration of
their perfect matchings encodes the numerator of the associated Laurent
polynomial while decompositions of the graphs correspond to the denominator.
This complements recent work by Schiffler and Carroll-Price for a cluster
expansion formula for the A_n case while providing a novel interpretation for
the B_n, C_n, and D_n cases.


title: Fundamental Limit to Linear One-Dimensional Slow Light Structures

abstract:
  Using a new general approach to limits in optical structures that counts
orthogonal waves generated by scattering, we derive an upper limit to the
number of bits of delay possible in one-dimensional slow light structures that
are based on linear optical response to the signal field. The limit is
essentially the product of the length of the structure in wavelengths and the
largest relative change in dielectric constant anywhere in the structure at any
frequency of interest. It holds for refractive index, absorption or gain
variations with arbitrary spectral or spatial form. It is otherwise completely
independent of the details of the structure's design, and does not rely on
concepts of group velocity or group delay.


title:
Entanglement between charge qubits induced by a common dissipative
  environment

abstract:
  We study entanglement generation between two charge qubits due to the strong
coupling with a common bosonic environment (Ohmic bath). The coupling to the
boson bath is a source of both quantum noise (leading to decoherence) and an
indirect interaction between qubits. As a result, two effects compete as a
function of the coupling strength with the bath: entanglement generation and
charge localization induced by the bath. These two competing effects lead to a
non-monotonic behavior of the concurrence as a function of the coupling
strength with the bath. As an application, we present results for charge qubits
based on double quantum dots.


title: External Momentum, Volume Effects, and the Nucleon Magnetic Moment

abstract:
  We analyze the determination of volume effects for correlation functions that
depend on an external momentum. As a specific example, we consider finite
volume nucleon current correlators, and focus on the nucleon magnetic moment.
Because the multipole decomposition relies on SO(3) rotational invariance, the
structure of such finite volume corrections is unrelated to infinite volume
multipole form factors. One can deduce volume corrections to the magnetic
moment only when a zero-mode photon coupling vanishes, as occurs at
next-to-leading order in heavy baryon chiral perturbation theory. To deduce
such finite volume corrections, however, one must assume continuous momentum
transfer. In practice, volume corrections with momentum transfer dependence are
required to address the extraction of the magnetic moment, or other observables
that arise in momentum dependent correlation functions. Additionally we shed
some light on a puzzle concerning differences in lattice form factor data at
equal values of momentum transfer squared.


title: Creation of macroscopic quantum superposition states by a measurement

abstract:
  We propose a novel protocol for the creation of macroscopic quantum
superposition (MQS) states based on a measurement of a non-monotonous function
of a quantum collective variable. The main advantage of this protocol is that
it does not require switching on and off nonlinear interactions in the system.
We predict this protocol to allow the creation of multiatom MQS by measuring
the number of atoms coherently outcoupled from a two-component (spinor)
Bose-Einstein condensate.


title: Holomorphic correspondences between CR manifolds

abstract:
  It is proved that a germ of a real analytic CR map from a smooth
real-analytic minimal CR manifold M to an essentially finite real-algebraic
generic submanifold M' of P^N of the same CR-dimension extends as a holomorphic
correspondence along M. Applications are given for pseudoconcave submanifolds
of P^N.


title: Computer Based Analytical Simulations of the Chiral Hadronic Processes

abstract:
  The availability of computational modeling tools for subatomic physics (Form,
FeynArts, FormCalc, and FeynCalc) has made it possible to perform sophisticated
calculations in perturbative quantum field theory. We have adapted these
packages in order to apply them to the effective chiral field theory of
hadronic interactions. A detailed description of this Computational Hadronic
Model is presented here, along with sample calculations.


title: Discrimination between evolution operators

abstract:
  Under broad conditions, evolutions due to two different Hamiltonians are
shown to lead at some moment to orthogonal states. For two spin-1/2 systems
subject to precession by different magnetic fields the achievement of
orthogonalization is demonstrated for every scenario but a special one. This
discrimination between evolutions is experimentally much simpler than
procedures proposed earlier based on either sequential or parallel application
of the unknown unitaries. A lower bound for the orthogonalization time is
proposed in terms of the properties of the two Hamiltonians.


title: Earth's extensive entropy bound

abstract:
  The possibility of planetary mass black hole production by crossing entropy
limits is addressed. Such a possibility is given by pointing out that two
geophysical quantities have comparable values: first, Earth's total negative
entropy flux integrated over geological time and, second, its extensive entropy
bound, which follows as a tighter bound to the Bekenstein limit when entropy is
an extensive function. The similarity between both numbers suggests that the
formation of black holes from planets may be possible through a strong
fluctuation toward thermodynamic equilibrium which results in gravothermal
instability and final collapse. Briefly discussed are implications for the
astronomical observation of low mass black holes and for Fermi's paradox.


title:
Off-center impurity in alkali halides: reorientation, electric
  polarization and pairing to F center. IV. Reorientational rate

abstract:
  This last Part IV is aimed at deriving relaxation rates (times) of an
off-center Li+ impurity. We follow Christov's reaction rate method to define
general rate equations in terms of the exact Mathieu eigenvalues, as well as of
harmonic-oscillator eigenvalues approximating for the energy spectrum near the
bottom of the reorientational wells. To calculate the rate in each particular
case, we derive configurational tunneling probabilities by either Mathieu
eigenfunctions or by harmonic oscillator eigenfunctions. The electron-transfer
probability is calculated by generalizing Landau-Zener's method. Typical
examples are considered and compared with experimental relaxation times in
KCl:Li+.


title:
Boundary of central tiles associated with Pisot beta-numeration and
  purely periodic expansions

abstract:
  This paper studies tilings related to the beta-transformation when beta is a
Pisot number (that is not supposed to be a unit). Then it applies the obtained
results to study the set of rational numbers having a purely periodic
beta-expansion. Special focus is given to some quadratic examples.


title: (Extra)Ordinary Gauge Mediation

abstract:
  We study models of "(extra)ordinary gauge mediation," which consist of taking
ordinary gauge mediation and extending the messenger superpotential to include
all renormalizable couplings consistent with SM gauge invariance and an
R-symmetry. We classify all such models and find that their phenomenology can
differ significantly from that of ordinary gauge mediation. Some highlights
include: arbitrary modifications of the squark/slepton mass relations, small mu
and Higgsino NLSP's, and the possibility of having fewer than one effective
messenger. We also show how these models lead naturally to extremely simple
examples of direct gauge mediation, where SUSY and R-symmetry breaking occur
not in a hidden sector, but due to the dynamics of the messenger sector itself.


title:
Baryon oscillations in galaxy and matter power-spectrum covariance
  matrices

abstract:
  We investigate large-amplitude baryon acoustic oscillations (BAO's) in
off-diagonal entries of cosmological power-spectrum covariance matrices. These
covariance-matrix BAO's describe the increased attenuation of power-spectrum
BAO's caused by upward fluctuations in large-scale power. We derive an analytic
approximation to covariance-matrix entries in the BAO regime, and check the
analytical predictions using N-body simulations. These BAO's look much stronger
than the BAO's in the power spectrum, but seem detectable only at about a
one-sigma level in gigaparsec-scale galaxy surveys. In estimating cosmological
parameters using matter or galaxy power spectra, including the
covariance-matrix BAO's can have a several-percent effect on error-bar widths
for some parameters directly related to the BAO's, such as the baryon fraction.
Also, we find that including the numerous galaxies in small haloes in a survey
can reduce error bars in these cosmological parameters more than the simple
reduction in shot noise might suggest.


title:
Star Formation History up to z = 7.4: Implications for Gamma-Ray Bursts
  and the Cosmic Metallicity Evolution

abstract:
  The current Swift sample of gamma-ray bursts (GRBs) with measured redshifts
allows to test the assumption that GRBs trace the star formation in the
Universe. Some authors have claimed that the rate of GRBs increases with cosmic
redshift faster than the star formation rate, whose cause is not known yet. In
this paper, I investigate the possibility for interpreting the observed
discrepancy between the GRB rate history and the star formation rate history by
the cosmic metallicity evolution, motivated by the observation that the cosmic
metallicity evolves with redshift and GRBs prefer to occur in low metallicity
galaxies. First, I derive a star formation history up to redshift z=7.4 from an
updated sample of star formation rate densities obtained by adding the new UV
measurements of Bouwens et al. and the new UV and infrared measurements of
Reddy et al. to the existing sample compiled by Hopkins & Beacom. Then,
adopting a simple model for the relation between the GRB production and the
cosmic metallicity history as proposed by Langer & Norman, I show that the
observed redshift distribution of the Swift GRBs can be reproduced with a
fairly good accuracy. Although the results are limited by the small size of the
GRB sample and the poorly understood selection biases in detection and
localization of GRBs and in redshift determination, they suggest that GRBs
trace both the star formation and the metallicity evolution. If the star
formation history can be accurately measured with other approaches, which is
presumably achievable in the near future, it will be possible to determine the
cosmic metallicity evolution with the study on the redshift distribution of
GRBs.


title:
A Comparison of Weak Lensing Measurements From Ground- and Space-Based
  Facilities

abstract:
  We assess the relative merits of weak lensing surveys, using overlapping
imaging data from the ground-based Subaru telescope and the Hubble Space
Telescope (HST). Our tests complement similar studies undertaken with simulated
data. From observations of 230,000 matched objects in the 2 square degree
COSMOS field, we identify the limit at which faint galaxy shapes can be
reliably measured from the ground. Our ground-based shear catalog achieves
sub-percent calibration bias compared to high resolution space-based data, for
galaxies brighter than i'~24.5 and with half-light radii larger than 1.8". This
selection corresponds to a surface density of ~15 galaxies per sq arcmin
compared to ~71 per sq arcmin from space. On the other hand the survey speed of
current ground-based facilities is much faster than that of HST, although this
gain is mitigated by the increased depth of space-based imaging desirable for
tomographic (3D) analyses. As an independent experiment, we also reconstruct
the projected mass distribution in the COSMOS field using both data sets, and
compare the derived cluster catalogs with those from X-ray observations. The
ground-based catalog achieves a reasonable degree of completeness, with minimal
contamination and no detected bias, for massive clusters at redshifts
0.2<z<0.5. The space-based data provide improved precision and a greater
sensitivity to clusters of lower mass or at higher redshift.


title:
Threshold singularities in the dynamic response of gapless integrable
  models

abstract:
  We develop a method of an asymptotically exact treatment of threshold
singularities in dynamic response functions of gapless integrable models. The
method utilizes the integrability to recast the original problem in terms of
the low-energy properties of a certain deformed Hamiltonian. The deformed
Hamiltonian is local, hence it can be analysed using the conventional field
theory methods. We apply the technique to spinless fermions on a lattice with
nearest-neighbors repulsion, and evaluate the exponent characterizing the
threshold singularity in the dynamic structure factor.


title:
Protoplanetary disk fragmentation with varying radiative physics,
  initial conditions and numerical techniques

abstract:
  We review recent results of SPH simulations of gravitational instability in
gaseous protoplanetary disks,emphasizing the role of thermodynamics in both
isolated and binary systems. Contradictory results appeared in the literature
regarding disk fragmentation at tens of AU from the central star are likely due
to the different treatment of radiation physics as well as reflecting different
initial conditions. Further progress on the subject requires extensive
comparisons between different codes with the requirement that the same initial
conditions are adopted. It is discussed how the local conditions of the disks
undergoing fragmentation at $R < 25$ AU in recent SPH simulations are in rough
agreement with the prediction of analytical models, with small differences
being likely related to the inability of analytical models to account for the
dynamics and thermodynamics of three-dimensional spiral shocks. We report that
radically different adaptive hydrodynamical codes, SPH and adaptive mesh
refinement (AMR), yield very similar results on disk fragmentation at
comparable resolution in the simple case of an isothermal equation of state. A
high number of refinements in AMR codes is necessary but not sufficient to
correctly follow fragmentation, rather an initial resolution of the grid high
enough to capture the wavelength of the strongest spiral modes when they are
still barely nonlinear is essential. These tests represent a useful benchmark
and a starting point for a forthcoming code comparison with realistic radiation
physics.


title: Detection of methane on Kuiper Belt Object (50000) Quaoar

abstract:
  The near-infrared spectrum of (50000) Quaoar obtained at the Keck Observatory
shows distinct absorption features of crystalline water ice, solid methane and
ethane, and possibly other higher order hydrocarbons. Quaoar is only the fifth
Kuiper belt object on which volatile ices have been detected. The small amount
of methane on an otherwise water ice dominated surface suggests that Quaoar is
a transition object between the dominant volatile-poor small Kuiper belt
objects (KBOs) and the few volatile-rich large KBOs such as Pluto and Eris.


title:
Numerical Study of a Three-Dimensional Mixed Ising Ferrimagnet in the
  Presence of an External Field

abstract:
  We present a numerical study based on Monte Carlo algorithm of the magnetic
properties of a mixed Ising ferrimagnetic model on a cubic lattice where spins
$\sigma =\pm 1/2$ and spins $S=0,\pm 1$ are in alternating sites on the
lattice. We carried out exact ground state calculations and employ a Monte
Carlo simulation to obtain the finite-temperature phase diagram of the model. A
compensation point appears when the next-nearest-neighbor interaction between
the spins $\sigma =\pm 1/2$ exceeds a minimum value. We found a strong
dependence of the compensation temperature with the interactions in the
Hamiltonian, particulary the crystal field and the external field. An applied
field can change the range of values of the compensation temperature from zero
up to a maximum value that depends on the field.


title:
HE 1113-0641: The Smallest Separation Gravitational Lens Identified by a
  Ground-based Optical Telescope

abstract:
  The Hamburg/ESO quasar HE 1113-0641 is found to be a quadruple gravitational
lens, based on observations with the twin 6.5m Magellan telescopes at the Las
Campanas Observatory, and subsequently with the Hubble Space Telescope. The
z_S=1.235 quasar appears in a cross configuration, with i' band magnitudes
ranging from 18.0 to 18.8. With a maximum image separation of 0.67'', this is
the smallest-separation quadruple ever identified using a ground-based optical
telescope. PSF subtraction reveals a faint lensing galaxy. A simple lens model
succeeds in predicting the observed positions of the components, but fails to
match their observed flux ratios by up to a magnitude. We estimate the redshift
of the lensing galaxy to be z_L~0.7. Time delay estimates are on the order of a
day, suggesting that the flux ratio anomalies are not due to variability of the
quasar, but may result from substructure or microlensing in the lens galaxy.


title:
Influence of Impact Parameter Fluctuations on Transverse Momentum
  Fluctuations

abstract:
  The preliminary NA49 results on the energy dependence of transverse momentum
fluctuations over the whole SPS energy range exhibit an unexpected effect. The
$\Phi_{p_{T}}$ fluctuation measure - used by the NA49 experiment - manifests a
different behavior for different charge combinations. Whereas the
$\Phi_{p_{T}}$ is consistent with zero and independent of energy for negatively
charged particles, it significantly increases for both all charged and
positively charged particles at lower SPS energies. The string-hadronic model
UrQMD is applied here to explain this effect. The UrQMD simulations show that
the number of protons is strongly correlated with impact parameter and that the
event-by-event impact parameter fluctuations are responsible for the
event-by-event transverse momentum fluctuations of positively charged and all
charged particles where protons are included. The observations presented in
this article are important for all experiments measuring event-by-event
fluctuations, especially for those using all charged particles in the analysis.
The results can be also crucial for detectors with acceptances extending to the
beam/target spectator domains.


title: On gradient Ricci solitons with Symmetry

abstract:
  We study gradient Ricci solitons with maximal symmetry. First we show that
there are no non-trivial homogeneous gradient Ricci solitons. Thus the most
symmetry one can expect is an isometric cohomogeneity one group action. Many
examples of cohomogeneity one gradient solitons have been constructed. However,
we apply the main result in our paper "Rigidity of gradient Ricci solitons" to
show that there are no noncompact cohomogeneity one shrinking gradient solitons
with nonnegative curvature.


title:
Surface Enhanced Raman Scattering Investigation of Uranium Hydride and
  Uranium Oxide

abstract:
  The present approach to SERS does not rely on a hihj electrical conductivity
substrate or admixture to enable the SERS process. The novelty of our method is
to create an artificial periodic electron distribution on a surface by
illumination with ultraviolet radiation whose photon energy is above the
photoelectric work function of the material.


title: Electromagnetic reactions on light nuclei using chiral effective theory

abstract:
  I describe the use of chiral effective theory (ChiET) to compute
electromagnetic reactions in two- and three-nucleon systems. I first explain
how chiral perturbation theory can be extended to the few-nucleon sector. I
then explain the predictions of the resulting ChiET for electron-deuteron
scattering, and how they will be tested by forthcoming data from BLAST. I
conclude by displaying predictions for elastic Compton scattering from
deuterium and Helium-3 nuclei. These computations, in concert with future data
from MAX-Lab and HIGS, should give significant new information on neutron
polarizabilities, and hence yield insight into the structure of the nucleon.


title:
Scalar field exact solutions for non-flat FLRW cosmology: A technique
  from non-linear Schr\"odinger-type formulation

abstract:
  We report a method of solving for canonical scalar field exact solution in a
non-flat FLRW universe with barotropic fluid using non-linear Schr\"{o}dinger
(NLS)-type formulation in comparison to the method in the standard Friedmann
framework. We consider phantom and non-phantom scalar field cases with
exponential and power-law accelerating expansion. Analysis on effective
equation of state to both cases of expansion is also performed. We speculate
and comment on some advantage and disadvantage of using the NLS formulation in
solving for the exact solution.


title: Hamilton relativity group for noninertial states in quantum mechanics

abstract:
  Physical states in quantum mechanics are rays in a Hilbert space. Projective
representations of a relativity group transform between the quantum physical
states that are in the admissible class. The physical observables of position,
time, energy and momentum are the Hermitian representation of the
Weyl-Heisenberg algebra. We show that there is a consistency condition that
requires the relativity group to be a subgroup of the group of automorphisms of
the Weyl-Heisenberg algebra. This, together with the requirement of the
invariance of classical time, results in the inhomogeneous Hamilton group that
is the relativity group for noninertial frames in classical Hamilton's
mechanics. The projective representation of a group is equivalent to unitary
representations of its central extension. The central extension of the
inhomogeneous Hamilton group and its corresponding Casimir invariants are
computed. One of the Casimir invariants is a generalized spin that is invariant
for noninertial states. It is the familiar inertial Galilean spin with
additional terms that may be compared to noninertial experimental results.


title: Statistical Methods for Investigating the Cosmic Ray Energy Spectrum

abstract:
  Two separate statistical tests are described and developed in order to test
un-binned data sets for adherence to the power-law form. The first test employs
the TP-statistic, a function defined to deviate from zero when the sample
deviates from the power-law form, regardless of the value of the power index.
The second test employs a likelihood ratio test to reject a power-law
background in favor of a model signal distribution with a cut-off.


title: A Possible Orbital Solution For The Triple Star WDS 18253+4846

abstract:
  We present here the orbital elements for the pair BC of visual binary star
WDS 18253+4846 (ADS 11344 = HD 170109) and ephemerides for the period
2008-2014. As the orbital elements of pair AB already existed we analyzed mass
ratio between these two pairs and concluded that components C is the biggest
one in this triple system.


title: Multichannel chiral approach for kaonic hydrogen

abstract:
  We present an exact solution to the $K^{-}$-proton bound state problem
formulated in the momentum space. The 1s level characteristics of the kaonic
hydrogen are described together with the available low energy $\bar{K}N$ data.


title:
On a Clique-Based Integer Programming Formulation of Vertex Colouring
  with Applications in Course Timetabling

abstract:
  Vertex colouring is a well-known problem in combinatorial optimisation, whose
alternative integer programming formulations have recently attracted
considerable attention. This paper briefly surveys seven known formulations of
vertex colouring and introduces a formulation of vertex colouring using a
suitable clique partition of the graph. This formulation is applicable in
timetabling applications, where such a clique partition of the conflict graph
is given implicitly. In contrast with some alternatives, the presented
formulation can also be easily extended to accommodate complex performance
indicators (``soft constraints'') imposed in a number of real-life course
timetabling applications. Its performance depends on the quality of the clique
partition, but encouraging empirical results for the Udine Course Timetabling
problem are reported.


title: On the existence of Lyapounov variables for Schroedinger evolution

abstract:
  The theory of (classical and) quantum mechanical microscopic irreversibility
developed by B. Misra, I. Prigogine and M. Courbage (MPC) and various other
contributors is based on the central notion of a Lyapounov variable - i.e., a
dynamical variable whose value varies monotonically as time increases.
Incompatibility between certain assumed properties of a Lyapounov variable and
semiboundedness of the spectrum of the Hamiltonian generating the quantum
dynamics led MPC to formulate their theory in Liouville space. In the present
paper it is proved, in a constructive way, that a Lyapounov variable can be
found within the standard Hilbert space formulation of quantum mechanics and,
hence, the MPC assumptions are more restrictive than necessary for the
construction of such a quantity. Moreover, as in the MPC theory, the existence
of a Lyapounov variable implies the existence of a transformation mapping the
original quantum mechanical problem to an equivalent irreversible
representation. In addition, it is proved that in the irreversible
representation there exists a natural time observable splitting the Hilbert
space at each t>0 into past and future subspaces.


title: A Kolmogorov Extension Theorem for POVMs

abstract:
  We prove a theorem about positive-operator-valued measures (POVMs) that is an
analog of the Kolmogorov extension theorem, a standard theorem of probability
theory. According to our theorem, if a sequence of POVMs G_n on $\mathbb{R}^n$
satisfies the consistency (or projectivity) condition $G_{n+1}(A\times
\mathbb{R}) = G_n(A)$ then there is a POVM G on the space
$\mathbb{R}^\mathbb{N}$ of infinite sequences that has G_n as its marginal for
the first n entries of the sequence. We also describe an application in quantum
theory.


title: Distributional Limits for the Symmetric Exclusion Process

abstract:
  Strong negative dependence properties have recently been proved for the
symmetric exclusion process. In this paper, we apply these results to prove
convergence to the Poisson and normal distributions for various functionals of
the process.


title: Vector bundles on contractible smooth schemes

abstract:
  We discuss algebraic vector bundles on smooth k-schemes X contractible from
the standpoint of A^1-homotopy theory; when k = C, the smooth manifolds X(C)
are contractible as topological spaces. The integral algebraic K-theory and
integral motivic cohomology of such schemes are that of Spec k. One might hope
that furthermore, and in analogy with the classification of topological vector
bundles on manifolds, algebraic vector bundles on such schemes are all
isomorphic to trivial bundles; this is almost certainly true when the scheme is
affine. However, in the non-affine case this is false: we show that
(essentially) every smooth A^1-contractible strictly quasi-affine scheme that
admits a U-torsor whose total space is affine, for U a unipotent group,
possesses a non-trivial vector bundle. Indeed we produce explicit arbitrary
dimensional families of non-isomorphic such schemes, with each scheme in the
family equipped with "as many" (i.e., arbitrary dimensional moduli of)
non-isomorphic vector bundles, of every sufficiently large rank n, as one
desires; neither the schemes nor the vector bundles on them are distinguishable
by algebraic K-theory. We also discuss the triviality of vector bundles for
certain smooth complex affine varieties whose underlying complex manifolds are
contractible, but that are not necessarily A^1-contractible.


title: Embedding Bratteli-Vershik systems in cellular automata

abstract:
  Many dynamical systems can be naturally represented as `Bratteli-Vershik' (or
`adic') systems, which provide an appealing combinatorial description of their
dynamics. If an adic system X satisfies two technical conditions (`focus' and
`bounded width') then we show how to represent X using a two-dimensional
subshift of finite type Y; each `row' in a Y-admissible configuration
corresponds to an infinite path in the Bratteli diagram of X, and the vertical
shift on Y corresponds to the `successor' map of X. Any Y-admissible
configuration can then be recoded as the spacetime diagram of a one-dimensional
cellular automaton F; in this way X is `embedded' in F (i.e. X is conjugate to
a subsystem of F). With this technique, we can embed many odometers, Toeplitz
systems, and constant-length substitution systems in one-dimensional cellular
automata.


title:
CARS polarized microscopy of three-dimensional director structures in
  liquid crystals

abstract:
  We demonstrate three-dimensional vibrational imaging of director structures
in liquid crystals using coherent anti-Stokes Raman scattering (CARS) polarized
microscopy. Spatial mapping of the structures is based on sensitivity of a
polarized CARS signal to orientation of anisotropic molecules in liquid
crystals. As an example, we study structures in a smectic material and
demonstrate that single-scan CARS and two-photon fluorescence images of
molecular orientation patterns are consistent with each other and with the
structure model.

categories: cond-mat.soft cond-mat.mtrl-sci physics.bio-ph physics.chem-ph physics.optics


title:
Effects of a tungsten addition on the morphological evolution, spatial
  correlations, and temporal evolution of a model Ni-Al-Cr superalloy

abstract:
  The effect of adding 2 at.% W to a model Ni-Al-Cr superalloy on the
morphological evolution, spatial correlations and temporal evolution of
g'(L12)-precipitates at 1073 K is studied with scanning electron microscopy and
atomic force microscopy. Adding W yields a larger microhardness, earlier onset
of spheroidal-to-cuboidal precipitate morphological transition, larger volume
fraction (from ~20 to 30%), reduction in coarsening kinetics by one third and a
larger number density (Nv) of smaller mean radii (<R>) precipitates. The
kinetics of <R> and interfacial area per unit volume obey t1/3 and t-1/3
relationships, respectively, which is consistent with coarsening driven by
interfacial energy reduction. The Nv power law dependencies deviate, however,
from model predictions indicating that a stationary-state is not achieved.
Quantitative analyses with precipitate size distributions, pair correlation
functions, and edge-to-edge interprecipitate distance distributions gives
insight into 2D microstructural evolution, including the elastically driven
transition from a uniform g'-distribution to one-dimensional <001>-strings to
eventually clustered packs of g'-precipitates in the less densely packed
Ni-Al-Cr alloy.


title: Speeding up HMC with better integrators

abstract:
  We discuss how dynamical fermion computations may be made yet cheaper by
using symplectic integrators that conserve energy much more accurately without
decreasing the integration step size. We first explain why symplectic
integrators exactly conserve a ``shadow'' Hamiltonian close to the desired one,
and how this Hamiltonian may be computed in terms of Poisson brackets. We then
discuss how classical mechanics may be implemented on Lie groups and derive the
form of the Poisson brackets and force terms for some interesting integrators
such as those making use of second derivatives of the action (Hessian or force
gradient integrators). We hope that these will be seen to greatly improve
energy conservation for only a small additional cost and that their use will
significantly reduce the cost of dynamical fermion computations.


title: Adaptive Multigrid Algorithm for the QCD Dirac-Wilson Operator

abstract:
  We present a new multigrid solver that is suitable for the Dirac operator in
the presence of disordered gauge fields. The key behind the success of the
algorithm is an adaptive projection onto the coarse grids that preserves the
near null space. The resulting algorithm has weak dependence on the gauge
coupling and exhibits mild critical slowing down in the chiral limit. Results
are presented for the Wilson Dirac operator of the 2d U(1) Schwinger model.


title: FFLO state in thin superconducting films

abstract:
  We present the analysis of the inhomogeneous Fulde-Ferrell-Larkin-Ovchinnikov
(FFLO) superconducting state in thin superconducting films in the parallel
magnetic field. For the tetragonal crystal symmetry (relevant to CeCoIn$_{5}$ -
the most probable candidate for the FFLO state formation) we predict a very
peculiar in-plane angular dependence of the FFLO critical field due to the
orbital effect. In the uniform superconducting state the critical field should
be isotropic. The magnetic field pins also the direction of the FFLO modulation
permitting thus to study the critical current anisotropy. Our calculations
reveal a strong critical current anisotropy in the FFLO state in sharp contrast
with the usual superconducting state. The predicted characteristic anisotropies
of the critical field and critical current may provide an unambiguous probe of
the FFLO phase formation.


title: Star Clusters in the Nearby Late-Type Galaxy NGC 1311

abstract:
  Ultraviolet, optical and near infrared images of the nearby (D ~ 5.5 Mpc) SBm
galaxy NGC 1311, obtained with the Hubble Space Telescope, reveal a small
population of 13 candidate star clusters. We identify candidate star clusters
based on a combination of their luminosity, extent and spectral energy
distribution. The masses of the cluster candidates range from ~1000 up to
~100000 Solar masses, and show a strong positive trend of larger mass with
increasing with cluster age. Such a trend follows from the fading and
dissolution of old, low-mass clusters, and the lack of any young super star
clusters of the sort often formed in strong starbursts. The cluster age
distribution is consistent with a bursting mode of cluster formation, with
active episodes of age ~10 Myr, ~100 Myr and ~1 Gyr. The ranges of age and mass
we probe are consistent with those of the star clusters found in quiescent
Local Group dwarf galaxies.


title:
Paramagnonlike excitations and spin diffusion in magnetic resonance
  studies of copper oxide superconductors

abstract:
  The relaxation function theory for a doped two-dimensional Heisenberg
antiferromagnetic system in the paramagnetic state for all wave vectors through
the Brillouin zone is presented in view of low frequency response of high-$T_c$
copper oxide superconductors. We deduced the regions of long lifetime [$T
\lesssim 400(1-4x)$ K] and "overdamped" [$T \gtrsim 700(1-4x)$ K]
paramagnonlike excitations in the temperature ($T$)-doping index ($x$) phase
diagram from plane oxygen nuclear spin-lattice relaxation rate $^{17}(1/T_1)$
data in up to optimally doped La$_{2-x}$Sr$_{x}$CuO$_{4}$ thus providing the
regimes for the spin wave concept and the ''overdamped'' mode.


title:
Coincidences of Dark Energy with Dark Matter -- Clues for a Simple
  Alternative?

abstract:
  A rare coincidence of scales in standard particle physics is needed to
explain why $\Lambda$ or the negative pressure of cosmological dark energy (DE)
coincides with the positive pressure $P_0$ of random motion of dark matter (DM)
in bright galaxies. Recently Zlosnik et al. (2007) propose to modify the
Einsteinian curvature by adding a non-linear pressure from a medium flowing
with a four-velocity vector field $U^\mu$. We propose to check whether a smooth
extension of GR with a simple kinetic Lagrangian of $U^\mu$ can be constructed,
and whether the pressure can bend space-time sufficiently to replace the roles
of a $w=-1$ DE, $w=0$ Cold DM and heavy neutrinos in explaining anomalous
accelerations at all scales. As a specific proof of concept we find a
Vector-for-$\Lambda$ model (${\mathbf V\Lambda}$-model) and its variants. With
essentially {\it no free parameters}, these appear broadly consistent with the
solar system, gravitational potentials in dwarf spiral galaxies and the bullet
cluster of galaxies, early universe with inflation, structure formation and
BBN, and late acceleration with a 1:3 ratio of DM:DE.


title: Top physics at the Tevatron Collider

abstract:
  The top quark has been discovered in 1995 at the CDF and DO experiments
located in the Tevatron ring at the Fermilab laboratory. After more than a
decade the Tevatron collider, with its center-of-mass energy collisions of 1.96
TeV, is still the only machine capable of producing such exceptionally heavy
particle. Here I present a selection of the most recent CDF and DO measurements
performed analyzing ~ 1 fb-1 of integrated luminosity.


title: Fast algorithms for matching CCD images to a stellar catalogue

abstract:
  Two new algorithms are described for matching two dimensional coordinate
lists of point sources that are signifcantly faster than previous methods. By
matching rarely occurring triangles (or more complex shapes) in the two lists,
and by ordering searches by decreasing probability of success, it is
demonstrated that very few candidates need be considered to find a successful
match. Moreover, by immediately testing the suitability of a potential match
using an efficient mechanism, the need to process the entire candidate set is
avoided, yielding considerable performance improvements. Triangles are
described by a cosine metric that reduces the density of triangle space,
permitting efficient searches. An alternative shape characterization method
that reduces computational overhead in the construction phase is discussed. The
algorithms are tested on a set of 10 063 wide-field survey images, with
fields-of-view up to 4.8 x 3.6 deg, successfully matching 100% of the images in
a mean elapsed time of 6 ms (2.4 GHz Athlon CPU). The elapsed time of the
searching phase is shown to vary by less than 1 ms for list sizes between 10
and 200 points, demonstrating that fast, robust searches may be completed in
nearly constant time, independent of list size.


title: Eternally inflating cosmologies from intersecting spacelike branes

abstract:
  Intersecting spacelike braneworld cosmologies are investigated. The time axis
is set on the scale parameter of extra space, which may include more than one
timelike metric. Obtained are eternally inflating (i.e. undergoing late-time
inflation) Robertson-Walker spacetime and extra space with a constant scale
factor. In the case of multibrane solutions, some dimensions are static or
shrink. The fact that the largest supersymmetry algebra contains 32
supercharges in 4 dimensions imposes a restriction on the geometry of extra
space.


title: Nonlinear completion of massive gravity of the Fierz-Pauli type

abstract:
  A possible nonlinear completion of massive gravity of the Fierz-Pauli type is
proposed. The theory describes a system consisting of a massive tensor field of
the Fierz-Pauli type and an additional massive vector field. Massless limit as
well as flat-spacetime limit can be taken smoothly. Constructing a nonlinear
version of the physical-state condition which drives an extra scalar ghost from
physical states is still unsettled.


title: Numerical removal of water-vapor effects from THz-TDS measurements

abstract:
  One source of disturbance in a pulsed T-ray signal is attributed to ambient
water vapor. Water molecules in the gas phase selectively absorb T-rays at
discrete frequencies corresponding to their molecular rotational transitions.
This results in prominent resonances spread over the T-ray spectrum, and in the
time domain the T-ray signal is observed as fluctuations after the main pulse.
These effects are generally undesired, since they may mask critical
spectroscopic data. So, ambient water vapor is commonly removed from the T-ray
path by using a closed chamber during the measurement. Yet, in some
applications a closed chamber is not applicable. This situation, therefore,
motivates the need for another method to reduce these unwanted artifacts. This
paper presents a study on a computational means to address the problem.
Initially, a complex frequency response of water vapor is modeled from a
spectroscopic catalog. Using a deconvolution technique, together with fine
tuning of the strength of each resonance, parts of the water-vapor response are
removed from a measured T-ray signal, with minimal signal distortion.


title: Hyperon-nucleon potentials from lattice QCD

abstract:
  We calculate $p\Xi^0$ potentials from the equal-time Bethe-Salpeter amplitude
measured in the quenched QCD simulation with the spatial lattice volume, (4.4
fm)$^3$. The standard Wilson gauge action with the gauge coupling $\beta=5.7$
on $32^4$ lattice together with the standard Wilson quark action are used. The
hopping parameter $\kappa_{ud}=0.1678$ is chosen for $u$ and $d$ quarks, which
corresponds to $m_{\pi}\simeq 0.37$ GeV. The physical strange quark mass is
used by taking the parameter $\kappa_s=0.1643$ which is deduced from the
physical $K$ meson mass. The lattice spacing $a=0.1420$ fm is determined by the
physical $\rho$ meson mass. We find that the $p\Xi^0$ potential has strong spin
dependence. Strong repulsive core is found in $^1S_0$ channel while the
effective central potential in the $^3S_1$ channel has relatively weak
repulsive core. The potentials also have weak attractive parts in the medium to
long distance region (0.6 fm $\lsim r \lsim 1.2$ fm) in both of the $^1S_0$ and
$^3S_1$ channels.


title: Subsonic Flows for the Full Euler Equations in Half Plane

abstract:
  We study the subsonic flows governed by full Euler equations in the half
plane bounded below by a piecewise smooth curve asymptotically approaching
x1-axis. Nonconstant conditions in the far field are prescribed to ensure the
real Euler flows. The Euler system is reduced to a single elliptic equation for
the stream function. The existence, uniqueness and asymptotic behaviors of the
solutions for the reduced equation are established by Schauder fixed point
argument and some delicate estimates. The existence of subsonic flows for the
original Euler system is proved based on the results for the reduced equation,
and their asymptotic behaviors in the far field are also obtained.


title: Cosmology of Gravitino LSP Scenario with Right-Handed Sneutrino NLSP

abstract:
  We consider supersymmetric model with right-handed (s)neutrinos where the
neutrino masses are purely Dirac-type. We discuss cosmology based on such a
scenario, paying particular attention to the case that the gravitino is the
lightest superparticles (LSP) while the right-handed sneutrino is the next-LSP.
It will be shown that the cosmological constraints on the gravitino-LSP
scenario (in particular, those from the big-bang nucleosynthesis) are
drastically relaxed in such a case. We will also consider the implication of
such scenario to the structure formation.


title:
Lattice calculation of the QGP viscosities - Present results and next
  project -

abstract:
  The shear and bulk viscosities of gluon plasma are calculated by accumulating
a large amount of data for the Matsubara Green function ($G_{\beta}(t_m)$) on
isotropic $24^3 \times 8$ and $16^3 \times 8$ lattices. In the case of
Iwasaki's improved action, the calculations of $G_{\beta}(t_m)$ are carried out
on roughly 6 million configurations, while for the standard action the
calculations are done on more than 16 million configurations. The shear
viscosities increase roughly with $T^3$, and $\eta/s$ ratios are close to the
KSS lower bound in the region where $1<T/T_c<25$. Using these data the bulk
viscosities are also determined in the region where $T/T_c < 2$. They are
roughly one order of magnitude smaller than the shear viscosities. Our next
target is to determine the transport coefficients more precisely by a
maximum-entropy method. For this purpose the most effective method may be to
adopt an anisotropic lattice. In this report, we study the possible systematic
error due to the deformation of the anisotropic lattice at short distances.
Near the critical temperature, it is found that the standard action suffers
from a large deformation on the anisotropic lattice at short distances, while
the deformation is slight for Iwasaki's improved action. To reduce the
fluctuation of the Matsubara Green function, the improvement of the energy
momentum tensor operator by using clover-type loops is promising. We are also
attempting to apply the multi-level algorithm to reduce fluctuation.


title: Twenty Years of Searching for (and Finding) Globular Cluster Pulsars

abstract:
  Globular clusters produce orders of magnitude more millisecond pulsars per
unit mass than the Galactic disk. Since the first cluster pulsar was uncovered
twenty years ago, at least 138 have been identified - most of which are binary
millisecond pulsars. Because of their origins involving stellar encounters,
many of these systems are exotic objects that would never be observed in the
Galactic disk. Examples include pulsar-main sequence binaries, extremely rapid
rotators (including the current record holder), and millisecond pulsars in
highly eccentric orbits. These systems are allowing new probes of the
interstellar medium, the equation of state of material at supra-nuclear
density, the mass distribution of neutron stars, and the dynamics of globular
clusters.


title: Homotopy on spatial graphs and generalized Sato-Levine invariants

abstract:
  Edge-homotopy and vertex-homotopy are equivalence relations on spatial graphs
which are generalizations of Milnor's link-homotopy. Fleming and the author
introduced some edge (resp. vertex)-homotopy invariants of spatial graphs by
applying the Sato-Levine invariant for the constituent 2-component
algebraically split links. In this paper, we construct some new edge (resp.
vertex)-homotopy invariants of spatial graphs without any restriction of
linking numbers of the constituent 2-component links by applying the
generalized Sato-Levine invariant.


title: Universal Baxterization for $\mathbb{Z}$-graded Hopf algebras

abstract:
  We present a method for Baxterizing solutions of the constant Yang-Baxter
equation associated with $\mathbb{Z}$-graded Hopf algebras. To demonstrate the
approach, we provide examples for the Taft algebras and the quantum group
$U_q[sl(2)]$.