title:
Anderson localisation for an interacting two-particle quantum system on
  ${\mathbb Z}$

abstract:
  We study spectral properties of a system of two quantum particles on an
integer lattice with a bounded short-range two-body interaction, in an external
random potential field $V(x,\omega)$ with independent, identically distributed
values. The main result is that if the common probability density $f$ of random
variables $V(x,\omega)$ is analytic in a strip around the real line and the
amplitude constant $g$ is large enough (i.e. the system is at high disorder),
then, with probability one, the spectrum of the two-particle lattice
Schroedinger operator $H(\omega)$ (bosonic or fermionic) is pure point, and all
eigen-functions decay exponentially. The proof given in this paper is based on
a refinement of a multiscale analysis (MSA) scheme proposed by von Dreifus and
Klein, adapted to incorporate lattice systems with interaction.


title:
Central Limit Theorem for the Excited Random Walk in dimension $d \geq
  2$

abstract:
  We prove that a law of large numbers and a central limit theorem hold for the
excited random walk model in every dimension $d \geq 2$.


title: Linear systems on a class of anticanonical rational threefolds

abstract:
  Let X be the blow-up of the three dimensional complex projective space along
r general points of a smooth elliptic quartic curve B of P^3 and let L be any
line bundle of X. The aim of this paper is to provide an explicit algorithm for
determining the dimension of H^0(X,L).


title: HUDF-JD2: Mid-infrared Evidence for a z~2 Luminous Infrared Galaxy

abstract:
  The Hubble Ultra Deep Field source JD2 presented in Mobasher et al. (2005) is
an unusual galaxy that is very faint at all wavelengths shortward of 1.1
micron. Photometric redshift fits to data at 0.4 to 8 microns yield a
significant probability that it is an extremely massive galaxy at z~6.5. In
this paper we present new photometry at 16 microns and 22 micron from Spitzer
Infrared Spectrograph (IRS) peak-up imaging of the Great Observatories Origins
Deep Survey (GOODS) fields. We find that the spectral energy distribution shows
a factor of ~4 rise in flux density between the 16 micron and 22 micron
bandpass which is most likely due to the entrance of polycyclic aromatic
hydrocarbon emission features into the 22 micron and 24 micron passbands. The
flux ratio between these bandpasses can be best fit by a z~1.7 luminous
infrared galaxy with a bolometric luminosity of (2-6)\times10^{11} L_sun
corresponding to a star-formation rate of 80 M_sun/yr. The predicted flux
density values at other longer wavelengths are below the detection limits of
current instrumentation but such sources could potentially be detected in
lensed submillimeter surveys. Re-evaluation of the optical/near-infrared
photometry continues to favor z>6 photometric redshift solutions, but we argue
that the consistency of the multiwavelength parameters of this galaxy with
other dusty starbursts favor the z~2 mid-infrared photometric redshift. The
data presented here provide evidence that optically undetected near-infrared
sources which are detected at 24 microns are most likely dusty, starburst
galaxies at a redshift of z~2 with stellar masses >10^{10} M_sun.


title: SQUID-based instrumentation for ultra-low-field MRI

abstract:
  Magnetic resonance imaging at ultra-low fields (ULF MRI) is a promising new
imaging method that uses SQUID sensors to measure the spatially encoded
precession of pre-polarized nuclear spin populations at a microtesla-range
measurement field. In this work, a seven-channel SQUID system designed for
simultaneous 3D ULF MRI and magnetoencephalography (MEG) is described. The
system includes seven second-order SQUID gradiometers, characterized by
magnetic field resolutions of 1.2 - 2.8 fT/rtHz. It is also equipped with five
sets of coils for 3D Fourier imaging with pre-polarization. Essential technical
details of the design are discussed. The system's ULF MRI performance is
demonstrated by multi-channel 3D images of a preserved sheep brain acquired at
46 microtesla measurement field with pre-polarization at 40 mT. The imaging
resolution is 2.5 mm x 2.5 mm x 5 mm. The ULF MRI images are compared to images
of the same brain acquired using conventional high-field MRI. Different ways to
improve imaging SNR are discussed.


title:
Manifestly covariant current matrix elements in the Point Form
  Relativistic Hamiltonian Dynamics

abstract:
  A manifestly covariant expression for the current matrix elements of three
quark bound systems is derived in the framework of the Point Form Relativistic
Hamiltonian Dynamics. The relativistic impulse approximation is assumed in the
model. A critical comparison is made with other expressions usually given in
the literature.


title: Universality of three gaugino anomalous dimensions in N=4 SYM

abstract:
  We study maximal helicity three gaugino operators in N=4 Super Yang-Mills
theory. We show that the lowest anomalous dimension of scaling operators with
generic finite spin can be expressed in terms of the universal anomalous
dimension appearing at twist-2. This statement is rigourously proved at three
loops. The reason for this universality between sectors with different twist is
the hidden psu(1|1) invariance of the su(2|1) subsector of the theory.


title:
Hyperbolicity of exact hydrodynamics for three-dimensional linearized
  Grad's equations

abstract:
  We extend a recent proof of hyperbolicity of the exact (to all orders in
Knudsen number) linear hydrodynamic equations [M. Colangeli et al, Phys. Rev. E
(2007), in press; arXiv:cond-mat/0703791v2] to the three-dimensional Grad's
moment system. A proof of an H-theorem is also presented.


title:
Lagrangian subcategories and braided tensor equivalences of twisted
  quantum doubles of finite groups

abstract:
  We classify Lagrangian subcategories of the representation category of a
twisted quantum double of a finite group. In view of results of 0704.0195v2
this gives a complete description of all braided tensor equivalent pairs of
twisted quantum doubles of finite groups. We also establish a canonical
bijection between Lagrangian subcategories of the representation category of a
twisted quantum double of a finite group G and module categories over the
category of twisted G-graded vector spaces such that the dual tensor category
is pointed. This can be viewed as a quantum version of V. Drinfeld's
characterization of homogeneous spaces of a Poisson-Lie group in terms of
Lagrangian subalgebras of the double of its Lie bialgebra. As a consequence, we
obtain that two group-theoretical fusion categories are weakly Morita
equivalent if and only if their centers are equivalent as braided tensor
categories.


title: Validating module network learning algorithms using simulated data

abstract:
  In recent years, several authors have used probabilistic graphical models to
learn expression modules and their regulatory programs from gene expression
data. Here, we demonstrate the use of the synthetic data generator SynTReN for
the purpose of testing and comparing module network learning algorithms. We
introduce a software package for learning module networks, called LeMoNe, which
incorporates a novel strategy for learning regulatory programs. Novelties
include the use of a bottom-up Bayesian hierarchical clustering to construct
the regulatory programs, and the use of a conditional entropy measure to assign
regulators to the regulation program nodes. Using SynTReN data, we test the
performance of LeMoNe in a completely controlled situation and assess the
effect of the methodological changes we made with respect to an existing
software package, namely Genomica. Additionally, we assess the effect of
various parameters, such as the size of the data set and the amount of noise,
on the inference performance. Overall, application of Genomica and LeMoNe to
simulated data sets gave comparable results. However, LeMoNe offers some
advantages, one of them being that the learning process is considerably faster
for larger data sets. Additionally, we show that the location of the regulators
in the LeMoNe regulation programs and their conditional entropy may be used to
prioritize regulators for functional validation, and that the combination of
the bottom-up clustering strategy with the conditional entropy-based assignment
of regulators improves the handling of missing or hidden regulators.


title: Generating Unexpected Spin Echoes in Dipolar Solids with Pi Pulses

abstract:
  NMR spin echo measurements of C-13 in C60, Y-89 in Y2O3, and Si-29 in silicon
are shown to defy conventional expectations when more that one pi pulse is
used. Multiple pi-pulse echo trains may either freeze our or accelerate the
decay of the signal, depending on the pi-pulse phase. Average Hamiltonian
theory, combined with exact quantum calculations, reveals an intrinsic cause
for these coherent phenomena: the dipolar coupling has a many-body effect
during any real, finite pulse.


title:
Orbital degeneracy removed by charge order in triangular antiferromagnet
  AgNiO2

abstract:
  We report a high-resolution neutron diffraction study on the
orbitally-degenerate spin-1/2 hexagonal antiferromagnet AgNiO2. A structural
transition to a tripled unit cell with expanded and contracted NiO6 octahedra
indicates root(3) x root(3) charge order on the Ni triangular lattice. This
suggests charge order as a possible mechanism of lifting the orbital degeneracy
in the presence of charge fluctuations, as an alternative to Jahn-Teller
distortions. A novel magnetic ground state is observed at base temperatures
with the electron-rich S = 1 Ni sites arranged in alternating ferromagnetic
rows on a triangular lattice, surrounded by a honeycomb network of non-magnetic
and metallic Ni ions. We also report first-principles band-structure
calculations that explain microscopically the origin of these phenomena.


title: A Simplification of Combinatorial Link Floer Homology

abstract:
  We define a new combinatorial complex computing the hat version of link Floer
homology over Z/2Z, which turns out to be significantly smaller than the
Manolescu-Ozsvath-Sarkar one.


title: Surjunctivity for cellular automata in Besicovitch spaces

abstract:
  The Besicovitch pseudodistance measures the relative size of the set of
points where two functions take different values; the quotient space modulo the
induced equivalence relation is endowed with a natural metric. We study the
behavior of cellular automata in the new topology and show that, under suitable
additional hypotheses, they retain certain properties possessed in the usual
product topology; in particular, that injectivity still implies surjectivity.


title:
BEC-BCS Crossover of a Trapped Two-Component Fermi Gas with Unequal
  Masses

abstract:
  We determine the energetically lowest lying states in the BEC-BCS crossover
regime of s-wave interacting two-component Fermi gases under harmonic
confinement by solving the many-body Schrodinger equation using two distinct
approaches. Essentially exact basis set expansion techniques are applied to
determine the energy spectrum of systems with N=4 fermions. Fixed-node
diffusion Monte Carlo methods are applied to systems with up to N=20 fermions,
and a discussion of different guiding functions used in the Monte Carlo
approach to impose the proper symmetry of the fermionic system is presented.
The energies are calculated as a function of the s-wave scattering length a_s
for N=2-20 fermions and different mass ratios \kappa of the two species. On the
BEC and BCS sides, our energies agree with analytically-determined first-order
correction terms. We extract the scattering length and the effective range of
the dimer-dimer system up to \kappa = 20. Our energies for the
strongly-interacting trapped system in the unitarity regime show no shell
structure, and are well described by a simple expression, whose functional form
can be derived using the local density approximation, with one or two
parameters. The universal parameter \xi for the trapped system for various
\kappa is determined, and comparisons with results for the homogeneous system
are presented.


title: Towards a new concept of photomultiplier based on silicon technology

abstract:
  In order to build a new concept of photomultiplier based on silicon
technology, design and characterization of 5x5 arrays of a new generation of
single photon avalanche diodes (SPAD) manufactured by ST-Microelectronics have
been performed. Single photons sensitivity, dark noise and timing resolution of
the SPAD- STM devices in several experimental conditions have been evaluated.
Moreover, the effects arising from the multiple integration of many elements
and the study of their common read-out have been deeply investigated.


title: Updating the Phase Diagram of the Gross-Neveu Model in 2+1 Dimensions

abstract:
  The method of optimized perturbation theory (OPT) is used to study the phase
diagram of the massless Gross-Neveu model in 2+1 dimensions. In the temperature
and chemical potential plane, our results give strong support to the existence
of a tricritical point and line of first order phase transition, previously
only suspected to exist from extensive lattice Monte Carlo simulations. In
addition of presenting these results we discuss how the OPT can be implemented
in conjunction with the Landau expansion in order to determine all the relevant
critical quantities.


title: A new spinfoam vertex for quantum gravity

abstract:
  We introduce a new spinfoam vertex to be used in models of 4d quantum gravity
based on SU(2) and SO(4) BF theory plus constraints. It can be seen as the
conventional vertex of SU(2) BF theory, the 15j symbol, in a particular basis
constructed using SU(2) coherent states. This basis makes the geometric
interpretation of the variables transparent: they are the vectors normal to the
triangles within each tetrahedron. We study the condition under which these
states can be considered semiclassical, and we show that the semiclassical ones
dominate the evaluation of quantum correlations. Finally, we describe how the
constraints reducing BF to gravity can be directly written in terms of the new
variables, and how the semiclassicality of the states might improve
understanding the correct way to implement the constraints.


title:
Small scale aspects of flows in proximity of the turbulent/non-turbulent
  interface

abstract:
  The work reported below is a first of its kind study of the properties of
turbulent flow without strong mean shear in a Newtonian fluid in proximity of
the turbulent/non-turbulent interface, with emphasis on the small scale
aspects. The main tools used are a three-dimensional particle tracking system
(3D-PTV) allowing to measure and follow in a Lagrangian manner the field of
velocity derivatives and direct numerical simulations (DNS). The comparison of
flow properties in the turbulent (A), intermediate (B) and non-turbulent (C)
regions in the proximity of the interface allows for direct observation of the
key physical processes underlying the entrainment phenomenon. The differences
between small scale strain and enstrophy are striking and point to the definite
scenario of turbulent entrainment via the viscous forces originating in strain.


title:
Emergence of Tricritical Point and Liquid-Gas Phase in the Massless 2+1
  Dimensional Gross-Neveu Model

abstract:
  A complete thermodynamical analysis of the 2+1 dimensional massless
Gross-Neveu model is performed using the optimized perturbation theory. This is
a non-perturbative method that allows us to go beyond the known large-N results
already at lowest order. Our results, for a finite number of fermion species,
N, show the existence of a tricritical point in the temperature and chemical
potential phase diagram for discrete chiral phase transition allowing us to
precisely to locate it. By studying the phase diagram in the pressure and
inverse density plane, we also show the existence of a liquid-gas phase, which,
so far, was unknown to exist in this model. Finally, we also derive N dependent
analytical expressions for the fermionic mass, critical temperature and
critical chemical potential.


title: On the near-equality case of the Positive Mass Theorem

abstract:
  The Positive Mass Conjecture states that any complete asymptotically flat
manifold of nonnnegative scalar curvature has nonnegative mass. Moreover, the
equality case of the Positive Mass Conjecture states that in the above
situation, if the mass is zero, then the Riemannian manifold must be Euclidean
space. The Positive Mass Conjecture was proved by R. Schoen and S.-T. Yau for
all manifolds of dimension less than 8, and it was proved by E. Witten for all
spin manifolds. In this paper, we consider complete asymptotically flat
manifolds of nonnegative scalar curvature that are also harmonically flat in an
end. We show that, whenever the Positive Mass Theorem holds, any appropriately
normalized sequence of such manifolds whose masses converge to zero must have
metrics that are uniformly converging to Euclidean metrics outside a compact
region. This result is an ingredient in a forthcoming proof, co-authored with
H. Bray, of the Riemannian Penrose inequality in dimensions less than 8.


title: Bimodality in spectator fragmentation

abstract:
  The fluctuations of the largest fragment charge of a partition and of the
charge asymmetries of the two or three largest fragments in spectator decays
following 197Au + 197Au collisions at 1000 MeV per nucleon are investigated.
The observed bimodal distributions at specific values of the sorting variable
Z_bound exhibit features known from percolation theory where they appear as
finite-size effects. The underlying configurational fluctuations seem generic
for fragmentation processes in small systems.


title:
Two Qubit Entanglement in $XYZ$ Magnetic Chain with DM Antisymmetric
  Anisotropic Exchange Interaction

abstract:
  In the present paper we study two qubit entanglement in the most general
$XYZ$ Heisenberg magnetic chain with (non)homogeneous magnetic fields and the
DM anisotropic antisymmetric exchange interaction, arising from the spin-orbit
coupling . The model includes all known results as particular cases, for both
antiferromagnetic and ferromagnetic $XX, XY, XXX, XXZ, XYZ$ chains. The
concurrence of two qubit thermal entanglement and its dependence on anisotropic
parameters, external magnetic field and temperature are studied in details. We
found that in all cases, inclusion of the DM interaction, which is responsible
for weak ferromagnetism in mainly antiferromagnetic crystals and spin
arrangement in low symmetry magnets, creates (when it does not exist) or
strengthens (when it exists) entanglement in $XYZ$ spin chain. This implies
existence of a relation between arrangement of spins and entanglement, in which
the DM coupling plays an essential role. It suggests also that anisotropic
antisymmetric exchange interaction could be an efficient control parameter of
entanglement in the general $XYZ$ case.


title:
Production of light particles by very strong and slowly varying magnetic
  fields

abstract:
  The possibility that around some astrophysical objects there are non-static
magnetic fields of enormous intensity suggests that in these situations real
particles may be produced. The slowness of the variation is compensated by the
huge intensity. The main issue is the production of e+,e- pairs annihilating
into photons and the direct production of photons, as one of the concurrent
process in the GRB (gamma ray bursts). Then some simple effects due to the
presence of the intense gravity are studied and finally a look is given to the
production of other kinds of particles.


title:
Entanglement in a Jaynes-Cummings Model with Two Atoms and Two Photon
  Modes

abstract:
  We investigate the conditions of entanglement for a system of two atoms and
two photon modes in vacuum, using the Jaynes-Cummings model in the
rotating-wave approximation. It is found, by generalizing the existing results,
that the strength of entanglement is a periodic function of time. We explicitly
show that our results are in agreement with the existing results of
entanglement conditions under appropriate limits. Results for the two-atom and
two-photon system are generalized to the case of arbitrary values for the
atomic energies, corresponding to photon modes frequencies. Though it is
apparently a generalization of the existing work, we have considered for the
first time both the resonant and nonresonant conditions and found a general
equation which could be true for both cases. Moreover, we show that periodicity
of the entanglement is a distinct feature of resonant system. Considering the
two atoms and two photons system, in detail, we setup an approach which could
be generalized for many particle systems and the resulting master equation can
also be analyzed.


title: Analytic models of plausible gravitational lens potentials

abstract:
  Gravitational lenses on galaxy scales are plausibly modelled as having
ellipsoidal symmetry and a universal dark matter density profile, with a Sersic
profile to describe the distribution of baryonic matter. Predicting all lensing
effects requires knowledge of the total lens potential: in this work we give
analytic forms for that of the above hybrid model. Emphasising that complex
lens potentials can be constructed from simpler components in linear
combination, we provide a recipe for attaining elliptical symmetry in either
projected mass or lens potential. We also provide analytic formulae for the
lens potentials of Sersic profiles for integer and half-integer index. We then
present formulae describing the gravitational lensing effects due to
smoothly-truncated universal density profiles in cold dark matter model. For
our isolated haloes the density profile falls off as radius to the minus fifth
or seventh power beyond the tidal radius, functional forms that allow all
orders of lens potential derivatives to be calculated analytically, while
ensuring a non-divergent total mass. We show how the observables predicted by
this profile differ from that of the original infinite-mass NFW profile.
Expressions for the gravitational flexion are highlighted. We show how
decreasing the tidal radius allows stripped haloes to be modelled, providing a
framework for a fuller investigation of dark matter substructure in galaxies
and clusters. Finally we remark on the need for finite mass halo profiles when
doing cosmological ray-tracing simulations, and the need for readily-calculable
higher order derivatives of the lens potential when studying catastrophes in
strong lenses.


title:
Screening in the QCD plasma: effects of the gluons and of the
  confinement

abstract:
  The effects of a thermalized gas of gluons in a q,q bar plasma is
investigated. Then the interplay between Debye screening and confinement is
analyzed in a simplified model. While the one-gluon exchange gives results very
similar, but not equal, to the electric case, the phenomenological introduction
of confinement leads to very different results.


title: Elucidation of Conformational Hysteresis on a Giant DNA

abstract:
  The conformational behavior of a giant DNA mediated by condensing agents in
the bulk solution has been investigated through experimental and theoretical
approaches. Experimentally, a pronounced conformational hysteresis is observed
for folding and unfolding processes, by increasing and decreasing the
concentration of condensing agent PEG (Polyethylene glycol), respectively. To
elucidate the observed hysteresis, a semiflexible chain model is studied by
using Monte Carlo simulations for the coil-globule transition. In the
simulations, the hysteresis loop emerges for stiff enough chains, indicating
distinct pathways for folding and unfolding processes. Also, our results show
that globular state is thermodynamically more stable than coiled state in the
hysteresis loop. Our findings suggest that increasing chain stiffness may
reduce the chain conformations relevant to the folding pathway, which impedes
the folding process.


title:
PSR J1453+1902 and the radio luminosities of solitary versus binary
  millisecond pulsars

abstract:
  We present 3 yr of timing observations for PSR J1453+1902, a 5.79-ms pulsar
discovered during a 430-MHz drift-scan survey with the Arecibo telescope. Our
observations show that PSR J1453+1902 is solitary and has a proper motion of
8(2) mas/yr. At the nominal distance of 1.2 kpc estimated from the pulsar's
dispersion measure, this corresponds to a transverse speed of 46(11) km/s,
typical of the millisecond pulsar population. We analyse the current sample of
55 millisecond pulsars in the Galactic disk and revisit the question of whether
the luminosities of isolated millisecond pulsars are different from their
binary counterparts. We demonstrate that the apparent differences in the
luminosity distributions seen in samples selected from 430-MHz surveys can be
explained by small-number statistics and observational selection biases. An
examination of the sample from 1400-MHz surveys shows no differences in the
distributions. The simplest conclusion from the current data is that the spin,
kinematic, spatial and luminosity distributions of isolated and binary
millisecond pulsars are consistent with a single homogeneous population.


title:
Identified particle measurements at large transverse momenta from p+p to
  Au+Au collisions at RHIC

abstract:
  Measurements of various particle species over an extended momentum range
provide a sensitive experimental tool for investigating particle production
mechanisms in hadronic collisions. Comparison of the spectral shapes from
different collision centralities measured with the STAR detector at RHIC allows
one to study the interplay of soft and hard particle production for mesons and
investigate various baryon-meson effects. Systematic studies of identified
particle spectra for various colliding systems and different incident energies
provide additional insights toward the interplay between fragmentation and
non-fragmentation contributions to the particle production. In these
proceedings we present a systematic study of transverse momentum spectra for
charged pions, protons and antiprotons from Au+Au and Cu+Cu data at
sqrt(s_NN)=200 and 62.4 GeV as a function of collision centrality. We compare
those measurements with p+p and d+Au data, investigating the system effects on
energy loss.


title: Modules-at-infinity for quantum vertex algebras

abstract:
  This is a sequel to \cite{li-qva1} and \cite{li-qva2} in a series to study
vertex algebra-like structures arising from various algebras such as quantum
affine algebras and Yangians. In this paper, we study two versions of the
double Yangian $DY_{\hbar}(sl_{2})$, denoted by $DY_{q}(sl_{2})$ and
$DY_{q}^{\infty}(sl_{2})$ with $q$ a nonzero complex number. For each nonzero
complex number $q$, we construct a quantum vertex algebra $V_{q}$ and prove
that every $DY_{q}(sl_{2})$-module is naturally a $V_{q}$-module. We also show
that $DY_{q}^{\infty}(sl_{2})$-modules are what we call
$V_{q}$-modules-at-infinity. To achieve this goal, we study what we call
$\S$-local subsets and quasi-local subsets of $\Hom (W,W((x^{-1})))$ for any
vector space $W$, and we prove that any $\S$-local subset generates a (weak)
quantum vertex algebra and that any quasi-local subset generates a vertex
algebra with $W$ as a (left) quasi module-at-infinity. Using this result we
associate the Lie algebra of pseudo-differential operators on the circle with
vertex algebras in terms of quasi modules-at-infinity.


title: Results of the IGEC-2 search for gravitational wave bursts during 2005

abstract:
  The network of resonant bar detectors of gravitational waves resumed
coordinated observations within the International Gravitational Event
Collaboration (IGEC-2). Four detectors are taking part in this collaboration:
ALLEGRO, AURIGA, EXPLORER and NAUTILUS. We present here the results of the
search for gravitational wave bursts over 6 months during 2005, when IGEC-2 was
the only gravitational wave observatory in operation. The network data analysis
implemented is based on a time coincidence search among AURIGA, EXPLORER and
NAUTILUS, keeping the data from ALLEGRO for follow-up studies. With respect to
the previous IGEC 1997-2000 observations, the amplitude sensitivity of the
detectors to bursts improved by a factor about 3 and the sensitivity bandwidths
are wider, so that the data analysis was tuned considering a larger class of
detectable waveforms. Thanks to the higher duty cycles of the single detectors,
we decided to focus the analysis on three-fold observation, so to ensure the
identification of any single candidate of gravitational waves (gw) with high
statistical confidence. The achieved false detection rate is as low as 1 per
century. No candidates were found.


title: Unparticle physics on direct CP violation

abstract:
  The effects of the peculiar CP conserving phases in unparticle propagators
are explored. We find that the phases have a great impact on CP-violation. We
adopt the decays $B_{d}\to \pi^{+} \pi^{-}$ and $B_{d}\to \ell^{-}\ell^{+}$ as
the illustrators to demonstrate the influences of these phases on the direct CP
asymmetries. In particular, we emphasize that unparticle physics is the only
model suggested to date that could give the direct CP asymmetries in $B_d\to
\ell^{-} \ell^{+}$ as large as 15%. We also point out that the unparticle
phases could be probed in $B\to K^* \ell^{+} \ell^{-}$ decays by using T-odd
correlations.


title: Dynamic Properties of Molecular Motors in Burnt-Bridge Models

abstract:
  Dynamic properties of molecular motors that fuel their motion by actively
interacting with underlying molecular tracks are studied theoretically via
discrete-state stochastic ``burnt-bridge'' models. The transport of the
particles is viewed as an effective diffusion along one-dimensional lattices
with periodically distributed weak links. When an unbiased random walker passes
the weak link it can be destroyed (``burned'') with probability p, providing a
bias in the motion of the molecular motor. A new theoretical approach that
allows one to calculate exactly all dynamic properties of motor proteins, such
as velocity and dispersion, at general conditions is presented. It is found
that dispersion is a decreasing function of the concentration of bridges, while
the dependence of dispersion on the burning probability is more complex. Our
calculations also show a gap in dispersion for very low concentrations of weak
links which indicates a dynamic phase transition between unbiased and biased
diffusion regimes. Theoretical findings are supported by Monte Carlo computer
simulations.


title: System size dependence of freeze-out properties at RHIC

abstract:
  The STAR experiment at RHIC has measured identified pi(+/-), K(+/-) and
p(pbar) spectra and ratios from sqrt(s_NN) = 62.4 and 200 GeV Cu+Cu collisions.
The new Cu+Cu results are studied with hydro-motivated blast-wave and
statistical model frameworks in order to characterize the freeze-out properties
of this system. Along with measurements from Au+Au and p+p collisions, the
obtained freeze-out parameters are discussed as a function of collision energy,
system size, centrality and inferred energy density. This multi-dimensional
systematic study reveals the importance of the collision geometry and furthers
our understanding of the QCD phases.


title: Light-Cone Distribution Amplitudes of Axial-vector Mesons

abstract:
  We have presented a detailed study of twist-2 and twist-3 light-cone
distribution amplitudes of $1^3P_1$ and $1^1P_1$ axial-vector mesons, based on
QCD conformal partial wave expansion. Applying equations of motion, the
twist-three two-parton light-cone distribution amplitudes can be expressed in
terms of leading-twist and twist-three three-parton light-cone distribution
amplitudes. The relevant G-parity invariant and violating parameters,
containing the corrections due to the SU(3) breaking effects, are evaluated
from the QCD sum rule method. The results for axial-vector decay constants of
$1^3P_1$ states are presented. The values of tensor decay constants and
Gegenbauer moments of the leading twist distribution amplitudes for $1^1P_1$
states are updated. Using Gell-Mann-Okubo mass formula, the mixing angle for
the $f_8$ and $f_1$ of $1^3P_1$ states is $\theta_{^3P_1}\sim 38^\circ$, and
that for $h_8$ and $h_1$ of $1^1P_1$ states is $\theta_{^1P_1}\sim 10^\circ$.
The detailed properties for physical states $f_1(1285), f_1(1420), h_1(1170)$,
and $h_1(1380)$ are given. Assuming the mixing angle between $K_{1A}$ and
$K_{1B}$ to be $\theta_K=45^\circ$ or $-45^\circ$, we also give the detailed
study for $K_1(1270)$ and $K_1(1400)$. Using the conformal partial wave
expansion, we obtain the models for light-cone distribution amplitudes,
containing contributions up to conformal spin 9/2. It is interesting to note
that some distribution amplitudes have significant asymmetric behaviors, which
should be phenomenologically attractive.


title: Learning to Bluff

abstract:
  The act of bluffing confounds game designers to this day. The very nature of
bluffing is even open for debate, adding further complication to the process of
creating intelligent virtual players that can bluff, and hence play,
realistically. Through the use of intelligent, learning agents, and carefully
designed agent outlooks, an agent can in fact learn to predict its opponents
reactions based not only on its own cards, but on the actions of those around
it. With this wider scope of understanding, an agent can in learn to bluff its
opponents, with the action representing not an illogical action, as bluffing is
often viewed, but rather as an act of maximising returns through an effective
statistical optimisation. By using a tee dee lambda learning algorithm to
continuously adapt neural network agent intelligence, agents have been shown to
be able to learn to bluff without outside prompting, and even to learn to call
each others bluffs in free, competitive play.


title:
On Lagrangian submanifolds in complex hyperquadrics and isoparametric
  hypersurfaces in spheres

abstract:
  The $n$-dimensional complex hyperquadric is a compact complex algebraic
hypersurface defined by the quadratic equation in the $(n+1)$-dimensional
complex projective space, which is isometric to the real Grassmann manifold of
oriented 2- planes and is a compact Hermitian symmetric space of rank 2. In
this paper we study geometry of compact Lagrangian submanifolds in complex
hyperquadrics from the viewpoint of the theory of isoparametric hypersurfaces
in spheres. From this viewpoint we provide a classification theorem of compact
homogeneous Lagrangian submanifolds in complex hyperquadrics by using the
moment map technique. Moreover we determine the Hamiltonian stability of
compact minimal Lagrangian submanifolds embedded in complex hyperquadrics which
are obtained as Gauss images of isoparametric hypersurfaces in spheres with
$g(=1,2,3)$ distinct principal curvatures.


title:
Quasiparticle Poisoning and Quantum Coherence in a Differential Charge
  Qubit

abstract:
  We demonstrate the operation of a differential single Cooper-pair box, a
charge qubit consisting of two aluminum islands, isolated from ground, coupled
by a pair of small-area Josephson junctions, and read out with a
superconducting differential radio-frequency single electron transistor. We
have tested four devices, all of which show evidence of quasiparticle
poisoning. The devices are characterized with microwave spectroscopy and
temperature dependence studies, and Coulomb staircases are shown to be
e-periodic in all samples. However, coherent control is still possible with
non-adiabatic voltage pulses. Coherent oscillation experiments and a relaxation
time measurement were performed using a charge derivative readout technique.


title: Primordial nucleosynthesis as a probe of fundamental physics parameters

abstract:
  We analyze the effect of variation of fundamental couplings and mass scales
on primordial nucleosynthesis in a systematic way. The first step establishes
the response of primordial element abundances to the variation of a large
number of nuclear physics parameters, including nuclear binding energies. We
find a strong influence of the n-p mass difference (for the 4He abundance), of
the nucleon mass (for deuterium) and of A=3,4,7 binding energies (for 3He, 6Li
and 7Li). A second step relates the nuclear parameters to the parameters of the
Standard Model of particle physics. The deuterium, and, above all, 7Li
abundances depend strongly on the average light quark mass hat{m} \equiv
(m_u+m_d)/2. We calculate the behaviour of abundances when variations of
fundamental parameters obey relations arising from grand unification. We also
discuss the possibility of a substantial shift in the lithium abundance while
the deuterium and 4He abundances are only weakly affected.


title: T-Parity Violation by Anomalies

abstract:
  Little Higgs theories often rely on an internal parity ("T-parity'') to
suppress non-standard electroweak effects or to provide a dark matter
candidate. We show that such a symmetry is generally broken by anomalies, as
described by the Wess-Zumino-Witten term. We study a simple SU(3) x SU(3)/SU(3)
Little Higgs scheme where we obtain a minimal form for the topological
interactions of a single Higgs field. The results apply to more general models,
including [SU(3) x SU(3)/SU(3)]^4, SU(5)/SO(5), and SU(6)/Sp(6).


title: Signed q-Analogs of Tornheim's Double Series

abstract:
  We introduce signed q-analogs of Tornheim's double series, and evaluate them
in terms of double q-Euler sums. As a consequence, we provide explicit
evaluations of signed and unsigned Tornheim double series, and correct some
mistakes in the literature.


title:
A Documentary of High-Mass Star Formation: Probing the Dynamical
  Evolution of Orion Source I on 10-100 AU Scales using SiO Masers

abstract:
  A comprehensive picture of high-mass star formation has remained elusive, in
part because examples of high-mass YSOs tend to be relatively distant, deeply
embedded, and confused with other emission sources. These factors have impeded
dynamical investigations within tens of AU of high-mass YSOs--scales that are
critical for probing the interfaces where outflows from accretion disks are
launched and collimated. Using observations of SiO masers obtained with the VLA
and the VLBA, the KaLYPSO project is overcoming these limitations by mapping
the structure and dynamical/temporal evolution of the material 10-1000 AU from
the nearest high-mass YSO: Radio Source I in the Orion BN/KL region. Our data
include ~40 epochs of VLBA observations over a several-year period, allowing us
to track the proper motions of individual SiO maser spots and to monitor
changes in the physical conditions of the emitting material with time.
Ultimately these data will provide 3-D maps of the outflow structure over
approximately 30% of the outflow crossing time. Here we summarize recent
results from the KaLYPSO project, including evidence that high-mass star
formation is occurring via disk-mediated accretion.


title: Inflated Beta Distributions

abstract:
  This paper considers the issue of modeling fractional data observed in the
interval [0,1), (0,1] or [0,1]. Mixed continuous-discrete distributions are
proposed. The beta distribution is used to describe the continuous component of
the model since its density can have quite diferent shapes depending on the
values of the two parameters that index the distribution. Properties of the
proposed distributions are examined. Also, maximum likelihood and method of
moments estimation is discussed. Finally, practical applications that employ
real data are presented.


title:
The Early Spectrophotometric Evolution of V1186 Scorpii (Nova Scorpii
  2004 #1)

abstract:
  We report optical photometry and optical through mid-infrared spectroscopy of
the classical nova V1186 Sco. This slowly developing nova had an complex light
curve with multiple secondary peaks similar to those seen in PW Vul. The time
to decline 2 magnitudes, t$_2$, was 20 days but the erratic nature of the light
curve makes determination of intrinsic properties based on the decline time
(e.g., luminosity) problematic, and the often cited MMRD relationship of Della
Valle and Livio (1995) fails to yield a plausible distance. Spectra covering
0.35 to 35 $\mu$m were obtained in two separate epochs during the first year of
outburst. The first set of spectra, taken about 2 months after visible maximum,
are typical of a CO-type nova with narrow line emission from \ion{H}{1},
\ion{Fe}{2}, \ion{O}{1} and \ion{He}{1}. Later data, obtained between 260 and
380 days after maximum, reveal an emerging nebular spectrum. \textit{Spitzer}
spectra show weakening hydrogen recombination emission with the emergence of
[\ion{Ne}{2}] (12.81 $\mu$m) as the strongest line. Strong emission from
[\ion{Ne}{3}] (15.56 $\mu$m) is also detected. Photoionization models with low
effective temperature sources and only marginal neon enhancement (Ne $\sim$ 1.3
Ne$_{\odot}$) are consistent with these IR fine-structure neon lines indicating
that V1186 Sco did not occur on a ONeMg white dwarf. In contrast, the slow and
erratic light curve evolution, spectral development, and photoionization
analysis of the ejecta imply the outburst occurred on a low mass CO white
dwarf. We note that this is the first time strong [\ion{Ne}{2}] lines have been
detected so early in the outburst of a CO nova and suggests that the presence
of mid-infrared neon lines is not directly indicative of a ONeMg nova event.


title: An X-ray Imaging Study of the Stellar Population in RCW49

abstract:
  We present the results of a high-resolution X-ray imaging study of the
stellar population in the Galactic massive star-forming region RCW49 and its
central OB association Westerlund 2. We obtained a 40 ks X-ray image of a
17'x17' field using the Chandra X-ray Observatory and deep NIR images using the
Infrared Survey Facility in a concentric 8'3x8'3 region. We detected 468 X-ray
sources and identified optical, NIR, and Spitzer Space Telescope MIR
counterparts for 379 of them. The unprecedented spatial resolution and
sensitivity of the X-ray image, enhanced by optical and infrared imaging data,
yielded the following results: (1) The central OB association Westerlund 2 is
resolved for the first time in the X-ray band. X-ray emission is detected from
all spectroscopically-identified early-type stars in this region. (2) Most
(86%) X-ray sources with optical or infrared identifications are cluster
members in comparison with a control field in the Galactic Plane. (3) A loose
constraint (2--5 kpc) for the distance to RCW49 is derived from the mean X-ray
luminosity of T Tauri stars. (4) The cluster X-ray population consists of
low-mass pre--main-sequence and early-type stars as obtained from X-ray and NIR
photometry. About 30 new OB star candidates are identified. (5) We estimate a
cluster radius of 6'--7' based on the X-ray surface number density profiles.
(6) A large fraction (90%) of cluster members are identified individually using
complimentary X-ray and MIR excess emission. (7) The brightest five X-ray
sources, two Wolf-Rayet stars and three O stars, have hard thermal spectra.


title: Production of a sterile species: quantum kinetics

abstract:
  Production of a sterile species is studied within an effective model of
active-sterile neutrino mixing in a medium in thermal equilibrium. The quantum
kinetic equations for the distribution functions and coherences are obtained
from two independent methods: the effective action and the quantum master
equation. The decoherence time scale for active-sterile oscillations is
$\tau_{dec} = 2/\Gamma_{aa}$, but the evolution of the distribution functions
is determined by the two different time scales associated with the damping
rates of the quasiparticle modes in the medium: $\Gamma_1=\Gamma_{aa}\cos^2\tm
; \Gamma_2=\Gamma_{aa}\sin^2\tm$ where $\Gamma_{aa}$ is the interaction rate of
the active species in absence of mixing and $\tm$ the mixing angle in the
medium. These two time scales are widely different away from MSW resonances and
preclude the kinetic description of active-sterile production in terms of a
simple rate equation. We give the complete set of quantum kinetic equations for
the active and sterile populations and coherences and discuss in detail the
various approximations. A generalization of the active-sterile transition
probability \emph{in a medium} is provided via the quantum master equation. We
derive explicitly the usual quantum kinetic equations in terms of the
``polarization vector'' and show their equivalence to those obtained from the
quantum master equation and effective action.


title:
Search for $D^0-{\bar D}^0$ Mixing Using Doubly Flavor Tagged
  Semileptonic Decay Modes

abstract:
  We have searched for $D^0 - \bar{D}^0$ mixing in $D^{*+} \to \pi^+ D^0$
decays with $D^0 \to K^{(*)} e \nu$ in a sample of $e^+ e^- \to {c\bar c}$
events produced near 10.58 GeV. The charge of the slow pion from charged $D^*$
decay tags the charm flavor at production, and it is required to be consistent
with the flavor of a fully reconstructed second charm decay in the same event.
We observe 3 mixed candidates compared to 2.85 background events expected from
simulation. We ascribe a 50% systematic uncertainty to this expected background
rate. We find a central value for the mixing rate of $0.4 \times 10^{-4}$.
Using a frequentist method, we set corresponding 68% and 90% confidence
intervals at $(-5.6, 7.4) \times 10^{-4}$ and $(-13, 12) \times 10^{-4}$,
respectively.


title: Non-commutative Renormalization

abstract:
  A new version of scale analysis and renormalization theory has been found on
the non-commutative Moyal space. It could be useful for physics beyond the
standard model or for standard physics in strong external field. The good news
is that quantum field theory is better behaved on non-commutative than on
ordinary space: indeed it has no Landau ghost. Noncommutativity might therefore
be an alternative to supersymmetry. We review this rapidly growing subject.


title:
Intervening Metal Systems in GRB and QSO sight-lines: The Mgii and Civ
  Question

abstract:
  Prochter et al. 2006 recently found that the number density of strong
intervening 0.5<z<2 MgII absorbers detected in gamma-ray burst (GRB) afterglow
spectra is nearly 4 times larger than in QSO spectra. We have conducted a
similar study using CIV absorbers. Our CIV sample, consisting of a total of 20
systems, is drawn from 3 high resolution and high to moderate S/N VLT/UVES
spectra of 3 long-duration GRB afterglows, covering the redshift interval 1.6<
z<3.1. The column density distribution and number density of this sample do not
show any statistical difference with the same quantities measured in QSO
spectra. We discuss several possibilities for the discrepancy between CIV and
MgII absorbers and conclude that a higher dust extinction in the MgII QSO
samples studied up to now would give the most straightforward solution.
However, this effect is only important for the strong MgII absorbers.
Regardless of the reasons for this discrepancy, this result confirms once more
that GRBs can be used to detect a side of the universe that was unknown before,
not necessarily connected with GRBs themselves, providing an alternative and
fundamental investigative tool of the cosmic evolution of the universe.


title: TeV Gamma-Ray Sources from a Survey of the Galactic Plane with Milagro

abstract:
  A survey of Galactic gamma-ray sources at a median energy of ~20 TeV has been
performed using the Milagro Gamma Ray Observatory. Eight candidate sources of
TeV emission are detected with pre-trials significance $>4.5\sigma$ in the
region of Galactic longitude $l\in[30^\circ,220^\circ]$ and latitude
$b\in[-10^\circ,10^\circ]$. Four of these sources, including the Crab nebula
and the recently published MGRO J2019+37, are observed with significances
$>4\sigma$ after accounting for the trials involved in searching the 3800
square degree region. All four of these sources are also coincident with EGRET
sources. Two of the lower significance sources are coincident with EGRET
sources and one of these sources is Geminga. The other two candidates are in
the Cygnus region of the Galaxy. Several of the sources appear to be spatially
extended. The fluxes of the sources at 20 TeV range from ~25% of the Crab flux
to nearly as bright as the Crab.


title: On Certain Quantization Aspects of (Generalized) Toda Systems

abstract:
  Ordinary and gl(n,R) generalized Toda systems as well as a related hierarchy
are probed with respect to certain quantization characteristics. "Quantum"
canonical and Poisson transformations are used to study quantizations of
transformed Toda systems. With a Lax pair setting, a hierarchy of related
systems are shown and their quantizations discussed. Finally, comments are
added about quantum aspects of gl(n,R) generalized Toda systems with the
approaches of deformation quantization or quantum groups in mind.


title: Polar Cremona Transformations and Monodromy of Polynomials

abstract:
  Consider the gradient map associated to any non-constant homogeneous
polynomial $f\in \C[x_0,...,x_n]$ of degree $d$, defined by \[\phi_f=grad(f):
D(f)\to \CP^n, (x_0:...:x_n)\to (f_0(x):...:f_n(x))\] where $D(f)=\{x\in \CP^n;
f(x)\neq 0\}$ is the principal open set associated to $f$ and
$f_i=\frac{\partial f}{\partial x_i}$. This map corresponds to polar Cremona
transformations. In Proposition \ref{p1} we give a new lower bound for the
degree $d(f)$ of $\phi_f$ under the assumption that the projective hypersurface
$V:f=0 $ has only isolated singularities. When $d(f)=1$, Theorem \ref{t4}
yields very strong conditions on the singularities of $V$.


title: On Conformally Kaehler, Einstein Manifolds

abstract:
  We prove that any compact complex surface with positive first Chern class
admits an Einstein metric which is conformally related to a Kaehler metric. The
key new ingredient is the existence of such a metric on the blow-up of the
complex projective plane at two distinct points.


title: Off-center HII regions in power-law density distributions

abstract:
  The expansion of ionization fronts in uniform and spherically symmetric
power-law density distributions is a well-studied topic. However, in many
situations, such as a star formed at the edge of a molecular cloud core, an
offset power-law density distribution would be more appropriate. In this paper
a few of the main issues of the formation and expansion of HII regions in such
media are outlined and results are presented for the particular cases where the
underlying power laws are 1/r^2 and 1/r^3. A simple criterion is developed for
determining whether the initial photoionized region will be unbounded, which
depends on the power-law exponent and the ratio of the equivalent Stroemgren
radius produced by the star in a uniform medium to the stellar offset distance.
In the expansion stage, the ionized volumes will eventually become unbounded
unless pressure balance with the external medium is reached before the
ionization front velocity becomes supersonic with respect to the ionized gas.


title: Reflection Positivity and Monotonicity

abstract:
  We prove general reflection positivity results for both scalar fields and
Dirac fields on a Riemannian manifold, and comment on applications to quantum
field theory. As another application, we prove the inequality $C_D \leq C_N$
between Dirichlet and Neumann covariance operators on a manifold with a
reflection.


title: Spin-exchange collisions of submerged shell atoms below 1 Kelvin

abstract:
  Angular momentum changing collisions can be suppressed in atoms whose valence
electrons are submerged beneath filled shells of higher principle quantum
number. To determine whether spin-exchange collisions are suppressed in these
"submerged shell" atoms, we measured spin-exchange collisions of six hyperfine
states of Mn at temperatures below 1 K. Although the 3d valence electrons in Mn
are submerged beneath a filled 4s orbital, we find that the spin exchange rate
coefficients are similar to those of Na and H (which are non-submerged shell
atoms).


title: CKM and Tri-bimaximal MNS Matrices in a SU(5) x (d)T Model

abstract:
  We propose a model based on SU(5) x {}^{(d)}T which successfully gives rise
to near tri-bimaximal leptonic mixing as well as realistic CKM matrix elements
for the quarks. The Georgi-Jarlskog relations for three generations are also
obtained. Due to the {}^{(d)}T transformation property of the matter fields,
the b-quark mass can be generated only when the {}^{(d)}T symmetry is broken,
giving a dynamical origin for the hierarchy between m_{b} and m_{t}. There are
only nine operators allowed in the Yukawa sector up to at least mass dimension
seven due to an additional Z_{12} x Z'_{12} symmetry, which also forbids, up to
some high orders, operators that lead to proton decay. The resulting model has
a total of nine parameters in the charged fermion and neutrino sectors, and
hence is very predictive. In addition to the prediction for \theta_{13} \simeq
\theta_{c}/3 \sqrt{2}, the model gives rise to a sum rule,
\tan^{2}\theta_{\odot} \simeq \tan^{2} \theta_{\odot, \mathrm{TBM}} - {1/2}
\theta_{c} \cos\beta, which is a consequence of the Georgi-Jarlskog relations
in the quark sector. This deviation could account for the difference between
the experimental best fit value for the solar mixing angle and the value
predicted by the tri-bimaximal mixing matrix.


title: Sum-product estimates via directed expanders

abstract:
  Let $\F_q$ be a finite field of order $q$ and $P$ be a polynomial in
$\F_q[x_1, x_2]$. For a set $A \subset \F_q$, define $P(A):=\{P(x_1, x_2) | x_i
\in A \}$. Using certain constructions of expanders, we characterize all
polynomials $P$ for which the following holds
  \vskip2mm \centerline{\it If $|A+A|$ is small, then $|P(A)|$ is large.}
\vskip2mm
  The case $P=x_1x_2$ corresponds to the well-known sum-product problem.


title: Light Curve Calculations of Supernovae from Fallback Gamma-Ray Bursts

abstract:
  The currently-favored model for long-duration gamma-ray bursts (GRBs) invokes
explosions from the collapse of a massive star down to a black hole: either
directly or through fallback. Those GRBs forming via fallback will produce much
less radioactive nickel, and hence it has been argued (without any real
calculation) that these systems produce dim supernovae. These fallback
black-hole GRBs have been recently been argued as possible progenitors of a
newly discovered set of GRBs lacking any associated supernovae. Here we present
the first ever radiation-hydrodynamics calculations of the light-curves
produced in the hypernova explosion by a delayed-fallback gamma-ray burst. We
find that the bolometric light-curve is dominated by shock-deposited energy,
not the decay of radioactive elements. As such, observations of such bursts
actually probe the density in the progenitor wind more than it does the
production of radioactive nickel.


title: Strange duality and the Hitchin/WZW connection

abstract:
  For a compact Riemann surface X of positive genus, the space of sections of
certain theta bundle on moduli of bundles of rank r and level k admits a
natural map to (the dual of) a similar space of sections of rank k and level r
(the strange duality isomorphism). Both sides of the isomorphism carry
projective connections as X varies in a family. We prove that this map is
(projectively) flat.


title: Field-Theoretic Simulations of Polyelectrolyte Complexation

abstract:
  We briefly discuss our recent field-theoretic study of polyelectrolyte
complexation, which occurs in solutions of two oppositely charged
polyelectrolytes. Charged systems require theoretical methods beyond the
mean-field (or self-consistent field) approximation; indeed, mean-field theory
is qualitatively incorrect for such polyelectrolyte solutions. Both analytical
(one-loop) and numerical (complex Langevin) methods to account for charge
correlations are discussed. In particular, the first application of
field-theoretic simulations to polyelectrolyte systems is reported. The
polyelectrolyte charge-charge correlation length and a phase diagram are
provided; effects of charge redistribution are qualitatively explored.


title: Limit cycles in the presence of convection, a travelling wave analysis

abstract:
  We consider a diffusion model with limit cycle reaction functions, in the
presence of convection. We select a set of functions derived from a realistic
reaction model: the Schnakenberg equations. This resultant form is
unsymmetrical. We find a transformation which maps the irregular equations into
model form. Next we transform the dependent variables into polar form. From
here, a travelling wave analysis is performed on the radial variable. Results
are complex, but we make some simple estimates.
  We carry out numerical experiments to test our analysis. An initial `knock'
starts the propagation of pattern. The speed of the travelling wave is not
quite as expected. We investigate further. The system demonstrates distinctly
different behaviour to the left and the right. We explain how this phenomenon
occurs by examining the underlying behaviour.


title:
Energy Distribution of a Charged Black Hole with a Minimally Coupled
  Scalar Field

abstract:
  Using three different energy-momentum complexes, the Einstein,
Landau-Lifshitz, and Papapetrou prescriptions, we calculate the energy of an
electrically charged black hole exact solution with a self-interacting,
minimally-coupled scalar field and the asymptotic region locally an
Anti-deSitter spacetime. Writing the metric in Kerr-Schild Cartesian
coordinates, we demonstrate that this metric belongs to the Kerr-Schild class
of solutions. Applying each of the three energy-momentum prescriptions and
comparing the results, we find consistency among these complexes, suggesting
their utility as localized measures of energy.


title:
Zero-variance zero-bias quantum Monte Carlo estimators of the
  spherically and system-averaged pair density

abstract:
  We construct improved quantum Monte Carlo estimators for the spherically- and
system-averaged electron pair density (i.e. the probability density of finding
two electrons separated by a relative distance u), also known as the
spherically-averaged electron position intracule density I(u), using the
general zero-variance zero-bias principle for observables, introduced by
Assaraf and Caffarel. The calculation of I(u) is made vastly more efficient by
replacing the average of the local delta-function operator by the average of a
smooth non-local operator that has several orders of magnitude smaller
variance. These new estimators also reduce the systematic error (or bias) of
the intracule density due to the approximate trial wave function. Used in
combination with the optimization of an increasing number of parameters in
trial Jastrow-Slater wave functions, they allow one to obtain well converged
correlated intracule densities for atoms and molecules. These ideas can be
applied to calculating any pair-correlation function in classical or quantum
Monte Carlo calculations.

categories: physics.chem-ph cond-mat.mtrl-sci cond-mat.other physics.comp-ph


title: BIons in topological string theory

abstract:
  When many fundamental strings are stacked together, they puff up into
D-branes. BIons and giant gravitons are the examples of such D-brane
configurations that arise from coincident strings. We propose and demonstrate
analogous transitions in topological string theory. Such transitions can also
be understood in terms of the Fourier transform of D-brane amplitudes.


title: Partial sums of the M{\"o}bius function

abstract:
  Assuming the Riemann Hypothesis we establish an upper bound for the sum of
the M{\" o}bius function up to $x$. Our method is based on estimating the
frequency with which intervals of a given length can contain an unusual number
of ordinates of zeros of the Riemann zeta-function.


title:
Reciprocal Symmetric Boltzmann Function and Unified Boson-Fermion
  Statistics

abstract:
  The differential equation for Boltzmann's function is replaced by the
corresponding discrete finite difference equation. The difference equation is,
then, symmetrized so that the equation remains invariant when step d is
replaced by -d. The solutions of this equation come in Boson-Fermion pairs.
Reciprocal symmetric Boltzmann's function, thus, unifies both Bosonic and
Fermionic distributions.


title: Toward Full Spatio-Temporal Control on the Nanoscale

abstract:
  We introduce an approach to implement full coherent control on nanometer
length scales. It is based on spatio-temporal modulation of the surface plasmon
polariton (SPP) fields at the thick edge of a nanowedge. The SPP wavepackets
propagating toward the sharp edge of this nanowedge are compressed and
adiabatically concentrated at a nanofocus, forming an ultrashort pulse of local
fields. The one-dimensional spatial profile and temporal waveform of this pulse
are completely coherently controlled.


title:
Diversity of Decline-Rate-Corrected Type Ia Supernova Rise Times: One
  Mode or Two?

abstract:
  B-band light-curve rise times for eight unusually well-observed nearby Type
Ia supernovae (SNe) are fitted by a newly developed template-building
algorithm, using light-curve functions that are smooth, flexible, and free of
potential bias from externally derived templates and other prior assumptions.
  From the available literature, photometric BVRI data collected over many
months, including the earliest points, are reconciled, combined, and fitted to
a unique time of explosion for each SN. On average, after they are corrected
for light-curve decline rate, three SNe rise in 18.81 +- 0.36 days, while five
SNe rise in 16.64 +- 0.21 days. If all eight SNe are sampled from a single
parent population (a hypothesis not favored by statistical tests), the rms
intrinsic scatter of the decline-rate-corrected SN rise time is 0.96 +0.52
-0.25 days -- a first measurement of this dispersion. The corresponding global
mean rise time is 17.44 +- 0.39 days, where the uncertainty is dominated by
intrinsic variance. This value is ~2 days shorter than two published averages
that nominally are twice as precise, though also based on small samples. When
comparing high-z to low-z SN luminosities for determining cosmological
parameters, bias can be introduced by use of a light-curve template with an
unrealistic rise time. If the period over which light curves are sampled
depends on z in a manner typical of current search and measurement strategies,
a two-day discrepancy in template rise time can bias the luminosity comparison
by ~0.03 magnitudes.


title: Multi-center MICZ-Kepler systems

abstract:
  We present the classical solutions of the two-center MICZ-Kepler and
MICZ-Kepler-Stark systems. Then we suggest the model of multi-center
MICZ-Kepler system on the curved spaces equipped with $so(3)$-invariant
conformal flat metrics.


title: Nonholonomic Ricci Flows: Exact Solutions and Gravity

abstract:
  In a number of physically important cases, the nonholonomically
(nonintegrable) constrained Ricci flows can be modelled by exact solutions of
Einstein equations with nonhomogeneous (anisotropic) cosmological constants. We
develop two geometric methods for constructing such solutions: The first
approach applies the formalism of nonholonomic frame deformations when the
gravitational evolution and field equations transform into systems of nonlinear
partial differential equations which can be integrated in general form. The
second approach develops a general scheme when one (two) parameter families of
exact solutions are defined by any source-free solutions of Einstein's
equations with one (two) Killing vector field(s). A successive iteration
procedure results in a class of solutions characterized by an infinite number
of parameters for a non-Abelian group involving arbitrary functions on one
variable. We also consider nonlinear superpositions of some mentioned classes
of solutions in order to construct more general integral varieties of the Ricci
flow and Einstein equations depending on infinite number of parameters and
three/ four coordinates on four/ five dimensional (semi) Riemannian spaces.


title:
Nonholonomic Ricci Flows and Parametric Deformations of the Solitonic
  pp--Waves and Schwarzschild Solutions

abstract:
  We study Ricci flows of some classes of physically valuable solutions in
Einstein and string gravity. The anholonomic frame method is applied for
generic off-diagonal metric ansatz when the field/ evolution equations are
transformed into exactly integrable systems of partial differential equations.
The integral varieties of such solutions, in four and five dimensional gravity,
depend on arbitrary generation and integration functions of one, two and/ or
three variables. Certain classes of nonholonomic frame constraints allow us to
select vacuum and/or Einstein metrics, to generalize such solutions for
nontrivial string (for instance, with antisymmetric torsion fields) and matter
field sources. A very important property of this approach (originating from
Finsler and Lagrange geometry but re-defined for semi-Riemannian spaces) is
that new classes of exact solutions can be generated by nonholonomic
deformations depending on parameters associated to some generalized Geroch
transforms and Ricci flow evolution. In this paper, we apply the method to
construct in explicit form some classes of exact solutions for multi-parameter
Einstein spaces and their nonholonomic Ricci flows describing evolutions/
interactions of solitonic pp-waves and deformations of the Schwarzschild
metric. We explore possible physical consequences and speculate on their
importance in modern gravity.


title:
Reciprocal Symmetry and Unified Classico-Quantum Oscillator And
  Consistency between a Particle in a Potential Well and a Harmonic Oscillator

abstract:
  The function exp(iwt) describes an oscillating motion. Energy of the
oscillator is proportional to the square of w. exp(iwt) is the solution of a
differential equation. We have replaced this differential equation by the
corresponding finite-time difference equation with d as the smallest span of
time. We have, then, symmetrized the equation so that it remains invariant
under the change d going to -d. This symmetric equation has solutions in pairs.
The angular speed w is modified to w' or w". w' contains a part with an
integer. w" contains a part with a half-integer. This corresponds to quantum
mechanical oscillator energy levels. F= a.exp(iwt) describes oscillation
between -a and +a. If we make w=0, F describes free oscillation between -a and
+a. Reciprocal symmetric oscillator, thus, unifies quantum and classical
harmonic oscillators on one hand, and a harmonic oscillator and a free particle
in a potential well on the other hand. No quantum mechanical postulates are
involved.


title:
Theory of enhanced dynamical photo-thermal bi-stability effects in
  cuprous oxide/organic hybrid heterostructure

abstract:
  We theoretically demonstrate the formation of multiple bi-stability regions
in the temperature pattern on the interface between a cuprous oxide quantum
well and DCM2:CA:PS organic compound. The Frenkel molecular exciton of the DCM2
is brought into resonance with the $1S$ quadrupole Wannier-Mott exciton in the
cuprous oxide by "solvatochromism" with CA. The resulting hybrid is thermalized
with surrounding helium bath. This leads to strongly non-linear temperature
dependence of the laser field detuning from the quadrupole exciton energy band
which is associated with the temperature induced red shift of the Wannier
exciton energy. Numerical up and down-scan for the detuning reveals
hysteresis-like temperature distribution. The obtained \emph{multiple}
bi-stability regions are at least three orders of magnitude bigger ($meV$) than
the experimentally observed bi-stability in bulk cuprous oxide ($\mu eV$). The
effective absorption curve exhibits highly asymmetrical behavior for the
Frenkel-like (above the $1S$ energy) and Wannier-like (below the $1S$ energy)
branches of the hybrid.


title:
Integrals Over Polytopes, Multiple Zeta Values and Polylogarithms, and
  Euler's Constant

abstract:
  Let $T$ be the triangle with vertices (1,0), (0,1), (1,1). We study certain
integrals over $T$, one of which was computed by Euler. We give expressions for
them both as a linear combination of multiple zeta values, and as a polynomial
in single zeta values. We obtain asymptotic expansions of the integrals, and of
sums of certain multiple zeta values with constant weight. We also give related
expressions for Euler's constant. In the final section, we evaluate more
general integrals -- one is a Chen (Drinfeld-Kontsevich) iterated integral --
over some polytopes that are higher-dimensional analogs of $T$. This leads to a
relation between certain multiple polylogarithm values and multiple zeta
values.


title:
Mixing and decoherence to nearest separable states in quantum
  measurements

abstract:
  We illustrate through numerical results a number of features of
environment-induced decoherence under a broad class of apparatus-environment
interactions in quantum measurements wherein the reduced system-apparatus
density matrix evolves towards the nearest separable state and, in addition,
there occurs a mixing in relevant groups of apparatus microstates (see below).
The resulting final state is unique and correctly embodies the measurement
statistics even in the absence of environment-induced superselection because of
energy differences between these groups of states. The partial transpose
remains non-positive throughout the process.


title: Soft constraint abstraction based on semiring homomorphism

abstract:
  The semiring-based constraint satisfaction problems (semiring CSPs), proposed
by Bistarelli, Montanari and Rossi \cite{BMR97}, is a very general framework of
soft constraints. In this paper we propose an abstraction scheme for soft
constraints that uses semiring homomorphism. To find optimal solutions of the
concrete problem, the idea is, first working in the abstract problem and
finding its optimal solutions, then using them to solve the concrete problem.
  In particular, we show that a mapping preserves optimal solutions if and only
if it is an order-reflecting semiring homomorphism. Moreover, for a semiring
homomorphism $\alpha$ and a problem $P$ over $S$, if $t$ is optimal in
$\alpha(P)$, then there is an optimal solution $\bar{t}$ of $P$ such that
$\bar{t}$ has the same value as $t$ in $\alpha(P)$.


title: AdS_3, Black Holes and Higher Derivative Corrections

abstract:
  Using AdS/CFT correspondence and the Euclidean action formalism for black
hole entropy Kraus and Larsen have argued that the entropy of a BTZ black hole
in three dimensional supergravity with (0,4) supersymmetry does not receive any
correction from higher derivative terms in the action. We argue that as a
consequence of AdS/CFT correspondence the action of a three dimensional
supergravity with (0,4) supersymmetry cannot receive any higher derivative
correction except for those which can be removed by field redefinition. The
non-renormalization of the entropy then follows as a consequence of this and
the invariance of Wald's formula under a field redefinition.


title: On monoidal equivalences and Ann-equivalences

abstract:
  In this paper, we show another proof of the problem by constructing a strict
monoidal category M(C) consisting of M-functors and M-morphisms of a category C
and we prove C is equivalent to it. The proof is based on a basic character of
monoidal equivalences. Ideas and techniques of these proofs can been used to
prove the equivalence between an Ann-category and an almost strict
Ann-category.


title:
Orbifoldes speciales et classification bimeromorphe des varietes
  kaehleriennes compactes

abstract:
  This is a sequel to [Ca01]=math.AG/0110051. We define the bimeromorphic {\it
category} of geometric orbifolds. These interpolate between (compact K\" ahler)
manifolds and such manifolds with logarithmic structure. These geometric
orbifolds are considered from the point of view of their geometry, and thus
equipped with the usual invariants of varieties: morphisms and bimeromorphic
maps, differential forms, fundamental groups and universal covers, fields of
definition and rational points. The most elementary properties, directly
adapted from the case of varieties without orbifold structure, are established
here. The arguments of [Ca01] can then be directly adapted to extend the main
structure results to this orbifold category. We hope to come back to deeper
aspects later. The motivation is that the natural frame for the theory of
classification of compact K\" ahler (and complex projective) manifolds includes
at least the category of orbifolds, as shown in [Ca01] by the fonctorial
decomposition of {\it special} manifolds as tower of orbifolds with either
$\kappa_+=-\infty$ or $\kappa=0$, and also, seemingly, by the minimal model
program, in which most proofs work only after the adjunction of a "boundary".
  Also, fibrations enjoy in the bimeromorphic category of geometric orbifolds
extension properties not satisfied in the category of varieties without
orbifold structure, permitting to express invariants of the total space from
those of the generic fibre and of the base. For example, the natural sequence
of fundamental groups is exact there; also the total space is special if so are
the generic fibre and the base. This makes this category suitable to lift
properties from orbifolds having either $\kappa_+=-\infty$ or $\kappa=0$ to
those which are special.


title: The Optimization of a Novel Prismatic Drive

abstract:
  The design of a mechanical transmission taking into account the transmitted
forces is reported in this paper. This transmission is based on Slide-o-Cam, a
cam mechanism with multiple rollers mounted on a common translating follower.
The design of Slide-o-Cam, a transmission intended to produce a sliding motion
from a turning drive, or vice versa, was reported elsewhere. This transmission
provides pure-rolling motion, thereby reducing the friction of rack-and-pinions
and linear drives. The pressure angle is a relevant performance index for this
transmission because it determines the amount of force transmitted to the load
vs. that transmitted to the machine frame. To assess the transmission
capability of the mechanism, the Hertz formula is introduced to calculate the
stresses on the rollers and on the cams. The final transmission is intended to
replace the current ball-screws in the Orthoglide, a three-DOF parallel robot
for the production of translational motions, currently under development for
machining applications at Ecole Centrale de Nantes.


title: Composability in a certain family of entropies

abstract:
  It is shown that the Tsallis entropies are the only entropies of the form
$H(P)=-\sum_i f(p_i)$, with suitable assumptions on $f$, satisfying the
condition of composability.


title: Gravitational lensing by stable C-field wormhole

abstract:
  It has been recently shown that Hoyle-Narlikar's C-field theory admits
wormhole geometry. We derive the deflection angle of light rays caused by
C-field wormhole in the strong field limit approach of gravitational lensing
theory. The linearized stability of C-field wormhole under spherically
symmetric perturbations about static equilibrium is also explored.


title: On the torsion of Brieskorn modules of homogeneous polynomials

abstract:
  Let $f\in \mathbb{C}[X_1,..., X_n]$ be a homogeneous polynomial and B(f) be
the corresponding Brieskorn module. We describe the torsion of the Brieskorn
module B(f) for n=2 and show that any torsion element has order 1. For n>2, we
find some examples in which the torsion order is strictly greater than 1.


title: MIMO detection employing Markov Chain Monte Carlo

abstract:
  We propose a soft-output detection scheme for Multiple-Input-Multiple-Output
(MIMO) systems. The detector employs Markov Chain Monte Carlo method to compute
bit reliabilities from the signals received and is thus suited for coded MIMO
systems. It offers a good trade-off between achievable performance and
algorithmic complexity.


title: Nonperturbative physics at short distances

abstract:
  There is accumulating evidence in lattice QCD that attempts to locate
confining fields in vacuum configurations bring results explicitly depending on
tha lattice spacing (that is, ultraviolet cut off). Generically, one deals with
low-dimensional vacuum defects which occupy a vanishing fraction of the total
four-dimensional space. We review briefly existing data on the vacuum defects
and their significance for confinement and other nonperturbative phenomena. We
introduce the notion of `quantum numbers' of the defects and draw an analogy,
rather formal one, to developments which took place about 50 years ago and were
triggered by creation of the Sakata model.


title: Classical and Quantum Interaction of the Dipole Revisited

abstract:
  The interaction of the electric and magnetic dipole moments of a particle
with the electromagnetic field is investigated in an approach that deals with
four-dimensional (4D) geometric quantities. The new commutation relations for
the 4D orbital and intrinsic angular momentums and also for the 4D dipole
moments are introduced. The expectation value of the quantum 4-force, which
holds in any frame, is worked out in terms of them. In contrast to it the whole
calculation in [1] ([1] J. Anandan, Phys. Rev. Lett. \textbf{85}, 1354 (2000))
has been made only in the rest frame of the dipole. It is proved that, e.g.,
the expression for the 3D force $\mathbf{f}%_{S}$ in [1] is not
relativistically correct and that the quantum 4-force is not zero in the
experiments proposed in [1]. This means that the phase shifts that could be
observed in such experiments are not topological phase shifts.


title: The ontology of temperature in nonequilibrium systems

abstract:
  The laws of thermodynamics provide a clear concept of the temperature for an
equilibrium system in the continuum limit. Meanwhile, the equipartition theorem
allows one to make a connection between the ensemble average of the kinetic
energy and the uniform temperature. When a system or its environment is far
from equilibrium, however, such an association does not necessarily apply. In
small systems, the regression hypothesis may not even apply. Herein, we show
that in small nonequilibrium systems, the regression hypothesis still holds
though with a generalized definition of the temperature. The latter must now be
defined for each such manifestation.


title:
The Higgs sector of the complex MSSM at two-loop order: QCD
  contributions

abstract:
  Results are presented for the leading two-loop contributions of O(alpha_t
alpha_s) to the masses and mixing effects in the Higgs sector of the MSSM with
complex parameters. They are obtained in the Feynman-diagrammatic approach
using on-shell renormalization. The full dependence on all complex phases is
taken into account. The renormalization of the appropriate contributions of the
Higgs-boson sector and the scalar top and bottom sector is discussed. Our
numerical analysis for the lightest MSSM Higgs-boson mass is based on the new
two-loop corrections, supplemented by the full one-loop result. The corrections
induced by the phase variation in the scalar top sector are enhanced by the
two-loop contributions. We find that the corresponding shift in M_h1 can amount
to 5 GeV.


title: Damped Corrections to Inflationary Spectra from a Fluctuating Cutoff

abstract:
  We reconsider trans-Planckian corrections to inflationary spectra by taking
into account a physical effect which has been overlooked and which could have
important consequences. We assume that the short length scale characterizing
the new physics is endowed with a finite width, the origin of which could be
found in quantum gravity. As a result, the leading corrections responsible for
superimposed osillations in the CMB temperature anisotropies are generically
damped by the blurring of the UV scale. To determine the observational
ramifications of this damping, we compare it to that which effectively occurs
when computing the angular power spectrum of temperature anisotropies. The
former gives an overall change of the oscillation amplitudes whereas the latter
depends on the angular scale. Therefore, in principle they could be
distinguished. In any case, the observation of superimposed oscillations would
place tight constraint on the variance of the UV cutoff.


title:
Ratios of star cluster core and half-mass radii: a cautionary note on
  intermediate-mass black holes in star clusters

abstract:
  There is currently much interest in the possible presence of
intermediate-mass black holes in the cores of globular clusters. Based on
theoretical arguments and simulation results it has previously been suggested
that a large core radius -- or particularly a large ratio of the core radius to
half-mass radius -- is a promising indicator for finding such a black hole in a
star cluster. In this study N-body models of 100000 stars with and without
primordial binaries are used to investigate the long-term structural evolution
of star clusters. Importantly, the simulation data is analysed using the same
processes by which structural parameters are extracted from observed star
clusters. This gives a ratio of the core and half-mass (or half-light) radii
that is directly comparable to the Galactic globular cluster sample. As a
result, it is shown that the ratios observed for the bulk of this sample can be
explained without the need for an intermediate-mass black hole. Furthermore, it
is possible that clusters with large core to half-light radius ratios harbour a
black-hole binary (comprised of stellar mass black holes) rather than a single
massive black hole. This work does not rule out the existence of
intermediate-mass black holes in the cores of at least some star clusters.


title: Evanescent quadrupole polariton

abstract:
  In the work we demonstrate the formation of new type of polariton on the
interface between a cuprous oxide slab and a polystyrene micro-sphere placed on
the slab. The evanescent field of the resonant whispering gallery mode (WGM)
has a substantial gradient, and therefore effectively couples with the
quadrupole $1S$ excitons in cuprous oxide. This evanescent polariton has a long
life-time ($1.7 ns$), which is determined only by its excitonic component. The
polariton lower branch has a well pronounced minimum. This suggests that this
excitation can be utilized for BEC. The spatial coherence of the polariton can
be improved by assembling the micro-spheres in a linear chain.


title: A Closer Look at a Gamma-Ray Burst

abstract:
  A study of gamma rays produced when stars collapse or collide reveals details
of the explosion mechanism, particularly the role of magnetic fields.


title: Approximate textual retrieval

abstract:
  An approximate textual retrieval algorithm for searching sources with high
levels of defects is presented. It considers splitting the words in a query
into two overlapping segments and subsequently building composite regular
expressions from interlacing subsets of the segments. This procedure reduces
the probability of missed occurrences due to source defects, yet diminishes the
retrieval of irrelevant, non-contextual occurrences.


title: The E_{11} origin of all maximal supergravities

abstract:
  Starting from the eleven dimensional E_{11} non-linear realisation of
M-theory we compute all possible forms, that is objects with totally
antisymmetrised indices, that occur in four dimensions and above as well as all
the 1-forms and 2-forms in three dimensions. In any dimension D, the D-1-forms
lead to maximal supergravity theories with cosmological constants and they are
in precise agreement with the patterns of gauging found in any dimension using
supersymmetry. The D-forms correspond to the presence of space-filling branes
which are crucial for the consistency of orientifold models and have not been
derived from an alternative approach, with the exception of the 10-dimensional
case. It follows that the gaugings of supergravities and the spacetime-filling
branes possess an eleven dimensional origin within the E_{11} formulation of
M-theory. This and previous results very strongly suggest that all the fields
in the adjoint representation of E_{11} have a physical interpretation.


title: Transcritical bifurcations in non-integrable Hamiltonian systems

abstract:
  We report on transcritical bifurcations of periodic orbits in non-integrable
two-dimensional Hamiltonian systems. We discuss their existence criteria and
some of their properties using a recent mathematical description of
transcritical bifurcations in families of symplectic maps. We then present
numerical examples of transcritical bifurcations in a class of generalized
H\'enon-Heiles Hamiltonians and illustrate their stabilities and unfoldings
under various perturbations of the Hamiltonians. We demonstrate that for
Hamiltonians containing straight-line librating orbits, the transcritical
bifurcation of these orbits is the typical case which occurs also in the
absence of any discrete symmetries, while their isochronous pitchfork
bifurcation is an exception. We determine the normal forms of both types of
bifurcations and derive the uniform approximation required to include
transcritically bifurcating orbits in the semiclassical trace formula for the
density of states of the quantum Hamiltonian. We compute the coarse-grained
density of states in a specific example both semiclassically and quantum
mechanically and find excellent agreement of the results.


title: Stallings' Foldings and Subgroups of Amalgams of Finite Groups

abstract:
  In the 1980's Stallings showed that every finitely generated subgroup of a
free group is canonically represented by a finite minimal immersion of a
bouquet of circles. In terms of the theory of automata, this is a minimal
finite inverse automaton. This allows for the deep algorithmic theory of finite
automata and finite inverse monoids to be used to answer questions about
finitely generated subgroups of free groups.
  In this paper we attempt to apply the same methods to other classes of
groups. A fundamental new problem is that the Stallings folding algorithm must
be modified to allow for ``sewing'' on relations of non-free groups. We look at
the class of groups that are amalgams of finite groups. It is known that these
groups are locally quasiconvex and thus all finitely generated subgroups are
represented by finite automata. We present an algorithm to compute such a
finite automaton and use it to solve various algorithmic problems.


title: Metallic phase in the two-dimensional ionic Hubbard model

abstract:
  We investigate the phases of the ionic Hubbard model in a two-dimensional
square lattice using determinant quantum Monte Carlo (DQMC). At half-filling,
when the interaction strength or the staggered potential dominate we find Mott
and band insulators, respectively. When these two energies are of the same
order we find a metallic region. Charge and magnetic structure factors
demonstrate the presence of antiferromagnetism only in the Mott region,
although the externally imposed density modulation is present everywhere in the
phase diagram. Away from half-filling, other insulating phases are found.
Kinetic energy correlations do not give clear signals for the existence of a
bond-ordered phase.


title: A generalized photon propagator

abstract:
  A covariant gauge independent derivation of the generalized dispersion
relation of electromagnetic waves in a medium with local and linear
constitutive law is presented. A generalized photon propagator is derived. For
Maxwell constitutive tensor, the standard light cone structure and the standard
Feynman propagator are reinstated.


title: A Pionic Hadron Explains the Muon Magnetic Moment Anomaly

abstract:
  A significant discrepancy exists between experiment and calculations of the
muon's magnetic moment. We find that standard formulas for the hadronic vacuum
polarization term have overlooked pionic states known to exist. Coulomb binding
alone guarantees $\pi^+ \pi^-$ states that quantum mechanically mix with the
$\rho$ meson. A simple 2-state mixing model explains the magnetic moment
discrepancy for a mixing angle of order $\alpha \sim 10^{-2}$. The relevant
physical state is predicted to give a tiny observable bump in the ratio R(s) of
$e^+ e^-$ annihilation at a low energy not previously searched. The burden of
proof is reversed for claims that conventional physics cannot explain the
muon's anomalous moment.


title: Equivalence of three-dimensional spacetimes

abstract:
  A solution to the equivalence problem in three-dimensional gravity is given
and a practically useful method to obtain a coordinate invariant description of
local geometry is presented. The method is a nontrivial adaptation of Karlhede
invariant classification of spacetimes of general relativity. The local
geometry is completely determined by the curvature tensor and a finite number
of its covariant derivatives in a frame where the components of the metric are
constants. The results are presented in the framework of real two-component
spinors in three-dimensional spacetimes, where the algebraic classifications of
the Ricci and Cotton-York spinors are given and their isotropy groups and
canonical forms are determined. As an application we discuss Goedel-type
spacetimes in three-dimensional General Relativity. The conditions for local
space and time homogeneity are derived and the equivalence of three-dimensional
Goedel-type spacetimes is studied and the results are compared with previous
works on four-dimensional Goedel-type spacetimes.


title: Algorithmic Problems in Amalgams of Finite Groups

abstract:
  Geometric methods proposed by Stallings for treating finitely generated
subgroups of free groups were successfully used to solve a wide collection of
decision problems for free groups and their subgroups.
  It turns out that Stallings' methods can be effectively generalized for the
class of amalgams of finite groups. In the present paper we employ subgroup
graphs constructed by the generalized Stallings' folding algorithm to solve
various algorithmic problems in amalgams of finite groups.


title:
Equivalence of LP Relaxation and Max-Product for Weighted Matching in
  General Graphs

abstract:
  Max-product belief propagation is a local, iterative algorithm to find the
mode/MAP estimate of a probability distribution. While it has been successfully
employed in a wide variety of applications, there are relatively few
theoretical guarantees of convergence and correctness for general loopy graphs
that may have many short cycles. Of these, even fewer provide exact ``necessary
and sufficient'' characterizations.
  In this paper we investigate the problem of using max-product to find the
maximum weight matching in an arbitrary graph with edge weights. This is done
by first constructing a probability distribution whose mode corresponds to the
optimal matching, and then running max-product. Weighted matching can also be
posed as an integer program, for which there is an LP relaxation. This
relaxation is not always tight. In this paper we show that \begin{enumerate}
\item If the LP relaxation is tight, then max-product always converges, and
that too to the correct answer. \item If the LP relaxation is loose, then
max-product does not converge. \end{enumerate} This provides an exact,
data-dependent characterization of max-product performance, and a precise
connection to LP relaxation, which is a well-studied optimization technique.
Also, since LP relaxation is known to be tight for bipartite graphs, our
results generalize other recent results on using max-product to find weighted
matchings in bipartite graphs.


title: Bayesian Approach to Neuro-Rough Models

abstract:
  This paper proposes a neuro-rough model based on multi-layered perceptron and
rough set. The neuro-rough model is then tested on modelling the risk of HIV
from demographic data. The model is formulated using Bayesian framework and
trained using Monte Carlo method and Metropolis criterion. When the model was
tested to estimate the risk of HIV infection given the demographic data it was
found to give the accuracy of 62%. The proposed model is able to combine the
accuracy of the Bayesian MLP model and the transparency of Bayesian rough set
model.


title:
The bounded isometry conjecture for the Kodaira-Thurston manifold and
  4-Torus

abstract:
  The purpose of this note is to study the bounded isometry conjecture proposed
by Lalonde and Polterovich. In particular, we show that the conjecture holds
for the Kodaira-Thurston manifold with the standard symplectic form and for the
4-torus with all linear symplectic forms.


title:
A new Generation of Spectrometer Calibration Techniques based on Optical
  Frequency Combs

abstract:
  Typical astronomical spectrographs have a resolution ranging between a few
hundred to 200.000. Deconvolution and correlation techniques are being employed
with a significance down to 1/1000 th of a pixel. HeAr and ThAr lamps are
usually used for calibration in low and high resolution spectroscopy,
respectively. Unfortunately, the emitted lines typically cover only a small
fraction of the spectrometer's spectral range. Furthermore, their exact
position depends strongly on environmental conditions. A problem is the strong
intensity variation between different (intensity ratios {>300). In addition,
the brightness of the lamps is insufficient to illuminate a spectrograph via an
integrating sphere, which in turn is important to calibrate a long-slit
spectrograph, as this is the only way to assure a uniform illumination of the
spectrograph pupil.
  Laboratory precision laser spectroscopy has experienced a major advance with
the development of optical frequency combs generated by pulsed femto-second
lasers. These lasers emit a broad spectrum (several hundred nanometers in the
visible and near infra-red) of equally-spaced "comb" lines with almost uniform
intensity (intensity ratios typically <10). Self-referencing of the laser
establishes a precise ruler in frequency space that can be stabilized to the
10e-18 uncertainty level, reaching absolute frequency inaccuracies at the
10e-12 level per day when using the Global Positioning System's (GPS) time
signal as the reference. The exploration of the merits of this new technology
holds the promise for broad-band, highly accurate and reproducible calibration
required for reliable operation of current and next generation astronomic
spectrometers.


title:
Symmetries in Differential Geometry: A Computational Approach to
  Prolongations

abstract:
  The aim of this work is to develop a systematic manner to close
overdetermined systems arising from conformal Killing tensors (CKT). The
research performs this action for 1-tensor and 2-tensors. This research makes
it possible to develop a new general method for any rank of CKT. This method
can also be applied to other types of Killing equations, as well as to
overdetermined systems constrained by some other conditions.
  The major methodological apparatus of the research is a decomposition of the
section bundles where the covariant derivatives of the CKT land via generalized
gradients. This decomposition generates a tree in which each row represents a
higher derivative. After using the conformal Killing equation, just a few
components (branches) survive, which means that most of them can be expressed
in terms of lower order terms. This results in a finite number of independent
jets. Thus, any higher covariant derivative can be written in terms of these
jets.
  The findings of this work are significant methodologically and, more
specifically, in the potential for the discovery of symmetries. First, this
work has uncovered a new method that could be used to close overdetermined
systems arising from conformal Killing tensors (CKT). Second, through an
application of this method, this research finds higher symmetry operators of
first and second degree, which are known by other means, for the Laplace
operator. The findings also reveal the first order symmetry operators for the
Yamabe case. Moreover, the research leads to conjectures about the second order
symmetries of the Yamabe operator.


title: Geometric dissipation in kinetic equations

abstract:
  A new symplectic variational approach is developed for modeling dissipation
in kinetic equations. This approach yields a double bracket structure in phase
space which generates kinetic equations representing coadjoint motion under
canonical transformations. The Vlasov example admits measure-valued
single-particle solutions. Such solutions are reversible; and the total entropy
is a Casimir, and thus is preserved.


title: Manifolds with 1/4-pinched Curvature are Space Forms

abstract:
  Let (M,g_0) be a compact Riemannian manifold with pointwise 1/4-pinched
sectional curvatures. We show that the Ricci flow deforms g_0 to a constant
curvature metric. The proof uses the fact, also established in this paper, that
positive isotropic curvature is preserved by the Ricci flow in all dimensions.
We also rely on earlier work of Hamilton and of Bohm and Wilking.


title: The Quantum-Corrected Fermion Mode Function during Inflation

abstract:
  My project computed the one loop fermion self-energy for massless Dirac +
Einstein in the presence of a locally de Sitter background. I employed
dimensional regularization and obtain a fully renormalized result by absorbing
all divergences with Bogliubov, Parasiuk, Hepp and Zimmermann (BPHZ)
counterterms. An interesting technical aspect of my computation was the need
for a noninvariant counterterm, owing to the breaking of de Sitter invariance
by our gauge condition. I also solved the effective Dirac equation for massless
fermions during inflation in the simplest gauge, including all one loop
corrections from quantum gravity. At late times the result for a spatial plane
wave behaves as if the classical solution were subjected to a time-dependent
field strength renormalization of Z_2(t) = 1 - 17(4 pi) *G H^2 *ln(a) + O(G^2).
I showed that this also follows from making the Hartree approximation, although
the numerical coefficients differ.


title:
A succinct method for investigating the sums of infinite series through
  differential formulae

abstract:
  Translation of "Methodus succincta summas serierum infinitarum per formulas
differentiales investigandi" (1780). Euler wants to represent some given series
of functions S(x)=X(x)+X(x+1)+X(x+2)+etc. in a different way. He writes S as a
series in derivatives of X with unknown coefficients. He makes a generating
function V(z) out of these coefficients, which is the same as a generating
function that involves the Bernoulli numbers.