title: On ergodic and mixing properties of the triangle map

abstract:
  In this paper we study in detail, both analytically and numerically, the
dynamical properties of the triangle map, a piecewise parabolic automorphism of
the two-dimensional torus, for different values of the two independent
parameters defining the map. The dynamics is studied numerically by means of
two different symbolic encoding schemes, both relying on the fact that it maps
polygons to polygons: in the first scheme we consider dynamically generated
partitions made out of suitable sets of disjoint polygons, in the second we
consider the standard binary partition of the torus induced by the
discontinuity set. These encoding schemes are studied in detail and shown to be
compatible, although not equivalent. The ergodic properties of the triangle map
are then investigated in terms of the Markov transition matrices associated to
the above schemes and furthermore compared to the spectral properties of the
Koopman operator in L2(T2). Finally, a stochastic version of the triangle map
is introduced and studied. A simple heuristic analysis of the latter yields the
correct statistical and scaling behaviours of the correlation functions of the
original map.


title: Interference Effects in the Brain

abstract:
  Interference effects are the most spectacular manifestation of the wave
nature of phenomena. This note proposes a systematic search for such effects in
the brain.


title:
Constructing Functional Braids for Low-Leakage Topological Quantum
  Computing

abstract:
  We discuss how to significantly reduce leakage errors in topological quantum
computation by introducing an irrelevant error in phase, using the construction
of a CNOT gate in the Fibonacci anyon model as a concrete example. To be
specific, we construct a functional braid in a six-anyon Hilbert space that
exchanges two neighboring anyons while conserving the encoded quantum
information. The leakage error is $\sim$$10^{-10}$ for a braid of $\sim$100
interchanges of anyons. Applying the braid greatly reduces the leakage error in
the construction of generic controlled-rotation gates.


title: Dalitz plot analysis of the D^+ -> K^-pi^+pi^+ decay

abstract:
  We perform a Dalitz plot analysis of D^+ -> K^-pi^+pi^+ decay with the CLEO-c
data set of 572 pb^-1 of e^+e^- collisions accumulated at the psi(3770). This
corresponds to 1.6 million D^+D^- pairs from which we select 140793 candidate
events with a small background of 1.1%. We compare our results with previous
measurements using the isobar model. We modify the isobar model with improved
description of some of the contributing resonances, and get better agreement
with our data. We also consider a quasi-model-independent approach and measure
the magnitude and phase of the contributing K pi S wave in the range of
invariant masses from the threshold to the maximum in this decay. This gives an
improved descriptions of our data over the isobar model. Finally we allow for
an isospin-two pi^+pi^+ S-wave contribution, and find that adding this to both
the isobar model and quasi-model-independent approach gives the best
description of our data.


title:
Equilibrium (Zipf) and Dynamic (Grasseberg-Procaccia) method based
  analyses of human texts. A comparison of natural (english) and artificial
  (esperanto) languages

abstract:
  A comparison of two english texts from Lewis Carroll, one (Alice in
wonderland), also translated into esperanto, the other (Through a looking
glass) are discussed in order to observe whether natural and artificial
languages significantly differ from each other. One dimensional time series
like signals are constructed using only word frequencies (FTS) or word lengths
(LTS). The data is studied through (i) a Zipf method for sorting out
correlations in the FTS and (ii) a Grassberger-Procaccia (GP) technique based
method for finding correlations in LTS. Features are compared : different power
laws are observed with characteristic exponents for the ranking properties, and
the {\it phase space attractor dimensionality}. The Zipf exponent can take
values much less than unity ($ca.$ 0.50 or 0.30) depending on how a sentence is
defined. This non-universality is conjectured to be a measure of the author
$style$. Moreover the attractor dimension $r$ is a simple function of the so
called phase space dimension $n$, i.e., $r = n^{\lambda}$, with $\lambda =
0.79$. Such an exponent should also conjecture to be a measure of the author
$creativity$. However, even though there are quantitative differences between
the original english text and its esperanto translation, the qualitative
differences are very minutes, indicating in this case a translation relatively
well respecting, along our analysis lines, the content of the author writing.


title:
The color gauge invariance and a possible origin of the Jaffe-Witten
  mass gap in QCD

abstract:
  The physical meaning of a mass gap introduced by Jaffe and Witten is to be
responsible for the large-scale (low-energy/momentum), i.e., the
non-perturbative structure of the true QCD vacuum. In order to make the
existence of a mass gap pefrectly clear it is defined as the difference between
the regularized full gluon self-energy and its subtracted (also regularized)
counterpart. The mass gap is mainly generated by the nonlinear interaction of
massless gluon modes. A self-consistent violation of SU(3) color gauge
invariance/symmetry is duscussed in order to realize a mass gap in QCD. For
this purpose, we propose not to impose the transversality condition on the full
gluon self-energy, while restoring the transversality of the full gluon
propagtor relevant for the non-perturbative QCD at the final stage. At the same
time, the Slavnov-Taylor identity for the full gluon propagator is always
preserved. All this allows one to establish the general structure of the full
gluon propagator in the presence of a mass gap. In this case, two independent
types of formal solutions for the full gluon propagator have been established.
The nonlinear iteration solution at which the gluons remain massless is
explicitly present. The existence of the solution with an effective gluon mass
is also demonstrated.


title:
Model error and sequential data assimilation. A deterministic
  formulation

abstract:
  Data assimilation schemes are confronted with the presence of model errors
arising from the imperfect description of atmospheric dynamics. These errors
are usually modeled on the basis of simple assumptions such as bias, white
noise, first order Markov process. In the present work, a formulation of the
sequential extended Kalman filter is proposed, based on recent findings on the
universal deterministic behavior of model errors in deep contrast with previous
approaches (Nicolis, 2004). This new scheme is applied in the context of a
spatially distributed system proposed by Lorenz (1996). It is found that (i)
for short times, the estimation error is accurately approximated by an
evolution law in which the variance of the model error (assumed to be a
deterministic process) evolves according to a quadratic law, in agreement with
the theory. Moreover, the correlation with the initial condition error appears
to play a secondary role in the short time dynamics of the estimation error
covariance. (ii) The deterministic description of the model error evolution,
incorporated into the classical extended Kalman filter equations, reveals that
substantial improvements of the filter accuracy can be gained as compared with
the classical white noise assumption. The universal, short time, quadratic law
for the evolution of the model error covariance matrix seems very promising for
modeling estimation error dynamics in sequential data assimilation.


title:
Signatures of polaronic charge ordering in optical and dc conductivity
  using dynamical mean field theory

abstract:
  We apply dynamical mean field theory to study a prototypical model that
describes charge ordering in the presence of both electron-lattice interactions
and intersite electrostatic repulsion between electrons. We calculate the
optical and d.c. conductivity, and derive approximate formulas valid in the
limiting electron-lattice coupling regimes. In the weak coupling regime, we
recover the usual behavior of charge density waves, characterized by a transfer
of spectral weight due to the opening of a gap in the excitation spectrum. In
the opposite limit of very strong electron-lattice coupling, instead, the
charge ordering transition is signaled by a global enhancement of the optical
absorption, with no appreciable spectral weight transfer. Such behavior is
related to the progressive suppression of thermally activated charge defects
taking place below the critical temperature. At intermediate values of the
coupling within the polaronic regime, a complex behavior is obtained where both
mechanisms of transfer and enhancement of spectral weight coexist.


title: Supernova VLBI in the present and with the SKA

abstract:
  VLBI is the only technology that will allow sub-milliarcsecond resolution
imaging in the near future. As such, it is the only way to image expanding
supernovae in nearby galaxies. Such images potentially allow us to study the
early evolution of neutron stars or black holes left behind by core-collapse
supernovae, the circumstellar wind history of the supernova progenitor stars,
the shock acceleration of cosmic-ray particles in supernovae as well as the
evolutionary process by which supernova shells merge into, and enrich, the ISM.
I will discuss the results of the on-going VLBI imaging campaigns on supernovae
1986J and 1993J. I will also discuss the impact on supernova VLBI of the
proposed South-African Karoo Array Telescope and Australian ASKAP arrays, as
well as the SKA itself, as these telescopes will greatly increase the
sensitivity of the global VLBI network.


title:
The kinematic status and mass content of the Sculptor dwarf spheroidal
  galaxy

abstract:
  We present VLT/FLAMES spectroscopic observations (R~6500) in the CaII triplet
region for 470 probable kinematic members of the Sculptor (Scl) dwarf
spheroidal galaxy. The accurate velocities (+- 2 km/s) and large area coverage
of Scl allow us to measure a velocity gradient of 7.6_{-2.2}^{+3.0} km/s
deg^{-1} along the Scl projected major axis, likely a signature of intrinsic
rotation. We also use our kinematic data to measure the mass distribution
within this system. By considering independently the kinematics of the distinct
stellar components known to be present in Scl, we are able to relieve known
degeneracies, and find that the observed velocity dispersion profiles are best
fitted by a cored dark matter halo with core radius r_c= 0.5 kpc and mass
enclosed within the last measured point M(< 1.8 kpc)=3.4 +- 0.7 x 10^8 M_sun,
assuming an increasingly radially anisotropic velocity ellipsoid. This results
in a mass-to-light ratio of 158+-33 (M/L)_sun inside 1.8 kpc. An NFW profile
with concentration c=20 and mass M(< 1.8 kpc) = 2.2_{-0.7}^{+1.0} x 10^8 M_sun
is also statistically consistent with the observations, but it tends to yield
poorer fits for the metal rich stars.


title: The Hierarchy Problem and the Self-Localized Higgs

abstract:
  We examine brane-world scenarios in which all the observed Standard Model
particles reside on a brane but the Higgs is an elementary extra-dimensional
scalar in the bulk. We show that, for codimension 2 branes, often-neglected
interactions between the bulk Higgs and the branes cause two novel effects.
First, they cause <H> to depend only logarithmically on the UV-sensitive
coefficient, m_B^2, of the mass term, m_B^2 H^*H, of the bulk potential, thus
providing a new mechanism for tackling the hierarchy problem. Second, the Higgs
brane couplings cause the lowest mass KK mode to localize near the brane
without any need for geometrical effects like warping. We explore some
preliminary implications such models have for the Higgs signature at the LHC,
both in the case where the extra dimensions arise at the TeV scale, and in ADD
models having Large Extra Dimensions. Novel Higgs features include couplings to
fermions which can be different from Standard Model values, m_f/v, despite the
fermions acquiring their mass completely from the Higgs expectation value.


title: Observation of D^+ to eta e^+ nu_e

abstract:
  Using a 281 pb^-1 data sample collected at the psi(3770) resonance with the
CLEO-c detector at the Cornell Electron Storage Ring, we report the first
observation of D^+ to eta e^+ nu_e. We also set upper limits for D^+ to eta'
e^+ nu_e and D^+ to phi e^+ nu_e that are about two orders of magnitude more
restrictive than those obtained by previous experiments.


title: Local analytic classification of $q$-difference equations with $|q|=1$

abstract:
  In this paper, we establish, under convenient diophantine assumptions, a
complete analytic classification of $q$-difference modules over the field of
germs of meromorphic functions at zero, proving some analytic analogs of the
results by Soibelman and Vologodsky, cf. math.AG/0205117, and by Baranovsky and
Ginzburg, cf. alg-geom/9607008.


title: Symplectic Reduction of Sheaves of $\mathcal{A}$-modules

abstract:
  Given an arbitrary sheaf $\mathcal{E}$ of $\mathcal{A}$-modules (or
$\mathcal{A}$-module in short) on a topological space $X$, we define
\textit{annihilator sheaves} of sub-$\mathcal{A}$-modules of $\mathcal{E}$ in a
way similar to the classical case, and obtain thereafter the analog of the
\textit{main theorem}, regarding classical annihilators in module theory, see
Curtis[\cite{curtis}, pp. 240-242]. The familiar classical properties,
satisfied by annihilator sheaves, allow us to set clearly the
\textit{sheaf-theoretic version} of \textit{symplectic reduction}, which is the
main goal in this paper.


title: Single-Proton Removal Reaction Study of 16B

abstract:
  The low-lying level structure of the unbound system $^{16}$B has been
investigated via single-proton removal from a 35 MeV/nucleon $^{17}$C beam. The
coincident detection of the beam velocity $^{15}$B fragment and neutron allowed
the relative energy of the in-flight decay of $^{16}$B to be reconstructed. The
resulting spectrum exhibited a narrow peak some 85 keV above threshold. It is
argued that this feature corresponds to a very narrow ($\Gamma \ll $100 keV)
resonance, or an unresolved multiplet, with a dominant $\pi (p_{3/2})^{-1}
\otimes \nu (d_{5/2}^3)_{J=3/2^+}$ + $\pi (p_{3/2})^{-1} \otimes \nu
(d_{5/2}^2,s_{1/2})_{J=3/2^+}$ configuration which decays by d-wave neutron
emission.


title: Limits Laws for Geometric Means of Free Random Variables

abstract:
  Let $\{T_{k}\}_{k=1}^{\infty}$ be a family of *--free identically distributed
operators in a finite von Neumann algebra. In this work we prove a
multiplicative version of the free central limit Theorem. More precisely, let
$B_{n}=T_{1}^{*}T_{2}^{*}... T_{n}^{*}T_{n}... T_{2}T_{1}$ then $B_{n}$ is a
positive operator and $B_{n}^{1/2n}$ converges in distribution to an operator
$\Lambda$. We completely determine the probability distribution $\nu$ of
$\Lambda$ from the distribution $\mu$ of $|T|^{2}$. This gives us a natural map
$\mathcal{G}:\mathcal{M_{+}}\to \mathcal{M_{+}}$ with $\mu\mapsto
\mathcal{G}(\mu)=\nu.$ We study how this map behaves with respect to additive
and multiplicative free convolution. As an interesting consequence of our
results, we illustrate the relation between the probability distribution $\nu$
and the distribution of the Lyapunov exponents for the sequence
$\{T_{k}\}_{k=1}^{\infty}$ introduced in \cite{LyaV}.


title: A Numerical Unitarity Formalism for One-Loop Amplitudes

abstract:
  The unitarity method for calculating one-loop amplitudes provides algorithms
of polynomial complexity. This is primarily beneficial for the computation of
multi-leg one loop amplitudes and it is therefore of great interest to develop
a numerical implementation of the unitarity method. We describe a
recently-developed, efficient, semi-numerical unitarity method for the
computation of the cut-constructible part of one-loop amplitudes.


title: Lepton Flavor Violation in Predictive Supersymmetric GUT Models

abstract:
  There have been many theoretical models constructed which aim to explain the
neutrino masses and mixing patterns. While many of the models will be
eliminated once more accurate determinations of the mixing parameters,
especially $\sin^2 2\theta_{13}$, are obtained, charged lepton flavor violation
(LFV) experiments are able to differentiate even further among the models. In
this paper, we investigate various rare LFV processes, such as $\ell_{i} \to
\ell_{j} + \gamma$ and $\mu-e$ conversion, in five predictive supersymmetric
(SUSY) SO(10) models and their allowed soft-SUSY breaking parameter space in
the constrained minimal SUSY standard model. Utilizing the Wilkinson Microwave
Anisotropy Probe dark matter constraints, we obtain lower bounds on the
branching ratios of these rare processes and find that at least three of the
five models we consider give rise to predictions for $\mu \to e + \gamma$ that
will be tested by the MEG Collaboration at PSI. In addition, the next
generation $\mu-e$ conversion experiment has sensitivity to the predictions of
all five models, making it an even more robust way to test these models. While
generic studies have emphasized the dependence of the branching ratios of these
rare processes on the reactor neutrino angle $\theta_{13}$ and the mass of the
heaviest right-handed neutrino $M_3$, we find very massive $M_3$ is more
significant than large $\theta_{13}$ in leading to branching ratios near to the
present upper limits.


title: Joint description of the e+e- annihilation into both four-pion channels

abstract:
  The e+e- --> pi+pi-pi0pi0 reaction cross section as a function of the
incident energy is calculated using a model that is an extension of our
recently published model of the e+e- annihilation into four charged pions. The
latter considered the intermediate states with the pi, rho, and a_1 mesons and
fixed the mixing angle of the a_1-rho-pi Lagrangian and other parameters by
fitting the cross section data. Here we supplement the original intermediate
states with those containing omega(782) and h_1(1170), but keep unchanged the
values of those parameters that enter both charged and mixed channel
calculations. The inclusion of omega is vital for obtaining a good fit to the
cross section data, while the intermediate states with h_1 further improve it.
Finally, we merge our models of the e+e- --> pi+pi-pi0pi0 and e+e- -->
pi+pi-pi+pi- reactions and obtain a simultaneous good fit.


title: Spinflation from Geometric Tachyon

abstract:
  We study the assisted inflation scenario from the rolling of $N$ BPS D3-brane
into the NS5-branes, on a transverse geometry of $R^3 \times S^1$, coupled to
four dimensional gravity. We assume that the branes are distributed along $S^1$
and the probe D3-branes spin along $R^3$ plane. Qualitatively this process is
similar to that of N-tachyon assisted inflation on unstable D-branes. We
further study the spinflation scenario numerically and analyze its effect.


title: Bi-partite entanglement entropy in integrable models with backscattering

abstract:
  In this paper we generalise the main result of a recent work by J. L. Cardy
and the present authors concerning the bi-partite entanglement entropy between
a connected region and its complement. There the expression of the leading
order correction to saturation in the large distance regime was obtained for
integrable quantum field theories possessing diagonal scattering matrices. It
was observed to depend only on the mass spectrum of the model and not on the
specific structure of the diagonal scattering matrix. Here we extend that
result to integrable models with backscattering (i.e. with non-diagonal
scattering matrices). We use again the replica method, which connects the
entanglement entropy to partition functions on Riemann surfaces with two branch
points. Our main conclusion is that the mentioned infrared correction takes
exactly the same form for theories with and without backscattering. In order to
give further support to this result, we provide a detailed analysis in the
sine-Gordon model in the coupling regime in which no bound states (breathers)
occur. As a consequence, we obtain the leading correction to the sine-Gordon
partition function on a Riemann surface in the large distance regime.
Observations are made concerning the limit of large number of sheets.


title:
Dynamical Masses for the Large Magellanic Cloud Massive Binary System
  [L72] LH 54-425

abstract:
  We present results from an optical spectroscopic investigation of the massive
binary system [L72] LH~54-425 in the LH 54 OB association in the Large
Magellanic Cloud. We revise the ephemeris of [L72] LH 54-425 and find an
orbital period of 2.247409 +/- 0.000010 days. We find spectral types of O3 V
for the primary and O5 V for the secondary. We made a combined solution of the
radial velocities and previously published V-band photometry to determine the
inclination for two system configurations, i = 52 degrees for the configuration
of the secondary star being more tidally distorted and i = 55 degrees for the
primary as the more tidally distorted star. We argue that the latter case is
more probable, and this solution yields masses and radii of M_1 = 47 +/- 2
M_Sun and R_1 = 11.4 +/- 0.1 R_Sun for the primary, and M_2 = 28 +/- 1 M_Sun
and R_2 = 8.1 +/- 0.1 R_Sun for the secondary. Our analysis places LH 54-425
amongst the most massive stars known. Based on the position of the two stars
plotted on a theoretical HR diagram, we find the age of the system to be about
1.5 Myr.


title:
Adaptive Sum Power Iterative Waterfilling for MIMO Cognitive Radio
  Channels

abstract:
  In this paper, the sum capacity of the Gaussian Multiple Input Multiple
Output (MIMO) Cognitive Radio Channel (MCC) is expressed as a convex problem
with finite number of linear constraints, allowing for polynomial time interior
point techniques to find the solution. In addition, a specialized class of sum
power iterative waterfilling algorithms is determined that exploits the
inherent structure of the sum capacity problem. These algorithms not only
determine the maximizing sum capacity value, but also the transmit policies
that achieve this optimum. The paper concludes by providing numerical results
which demonstrate that the algorithm takes very few iterations to converge to
the optimum.


title:
A Sample of Quasars with Strong Nitrogen Emission Lines from the Sloan
  Digital Sky Survey

abstract:
  We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750
emission lines (rest-frame equivalent width > 3 \AA) at 1.7 < z < 4.0 selected
from the Sloan Digital Sky Survey (SDSS) Fifth Data Release. These
nitrogen-rich (N-rich) objects comprise ~1.1% of the SDSS quasars. The
comparison between the N-rich quasars and other quasars shows that the two
quasar subsets share many common properties. We also confirm previous results
that N-rich quasars have much stronger Lya and NV lambda 1240 emission lines.
Strong nitrogen emission in all ionization states indicates high overall
nitrogen abundances in these objects. We find evidence that the nitrogen
abundance is closely related to quasar radio properties. The radio-loud
fraction in the NIII]-rich quasars is 26% and in the NIV]-rich quasars is 69%,
significantly higher than ~8% measured in other quasars with similar redshift
and luminosity. Therefore, the high nitrogen abundance in N-rich quasars could
be an indicator of a special quasar evolution stage, in which the radio
activity is also strong.


title:
Generalized Bloch analysis and propagators on Riemannian manifolds with
  a discrete symmetry

abstract:
  We consider an invariant quantum Hamiltonian $H=-\Delta_{LB}+V$ in the
$L^{2}$ space based on a Riemannian manifold $\tilde{M}$ with a countable
discrete symmetry group $\Gamma$. Typically, $\tilde{M}$ is the universal
covering space of a multiply connected Riemannian manifold $M$ and $\Gamma$ is
the fundamental group of $M$. On the one hand, following the basic step of the
Bloch analysis, one decomposes the $L^{2}$ space over $\tilde{M}$ into a direct
integral of Hilbert spaces formed by equivariant functions on $\tilde{M}$. The
Hamiltonian $H$ decomposes correspondingly, with each component $H_{\Lambda}$
being defined by a quasi-periodic boundary condition. The quasi-periodic
boundary conditions are in turn determined by irreducible unitary
representations $\Lambda$ of $\Gamma$. On the other hand, fixing a
quasi-periodic boundary condition (i.e., a unitary representation $\Lambda$ of
$\Gamma$) one can express the corresponding propagator in terms of the
propagator associated to the Hamiltonian $H$. We discuss these procedures in
detail and show that in a sense they are mutually inverse.


title: Frame transforms, star products and quantum mechanics on phase space

abstract:
  Using the notions of frame transform and of square integrable projective
representation of a locally compact group $G$, we introduce a class of
isometries (tight frame transforms) from the space of Hilbert-Schmidt operators
in the carrier Hilbert space of the representation into the space of square
integrable functions on the direct product group $G\times G$. These transforms
have remarkable properties. In particular, their ranges are reproducing kernel
Hilbert spaces endowed with a suitable 'star product' which mimics, at the
level of functions, the original product of operators. A 'phase space
formulation' of quantum mechanics relying on the frame transforms introduced in
the present paper, and the link of these maps with both the Wigner transform
and the wavelet transform are discussed.


title: Safety alternating automata on data words

abstract:
  A data word is a sequence of pairs of a letter from a finite alphabet and an
element from an infinite set, where the latter can only be compared for
equality. Safety one-way alternating automata with one register on infinite
data words are considered, their nonemptiness is shown EXPSPACE-complete, and
their inclusion decidable but not primitive recursive. The same complexity
bounds are obtained for satisfiability and refinement, respectively, for the
safety fragment of linear temporal logic with freeze quantification. Dropping
the safety restriction, adding past temporal operators, or adding one more
register, each causes undecidability.


title: Multi-epoch spectroscopy of the globular cluster black hole in NGC 4472

abstract:
  We present a study of the X-ray spectral properties of the highly variable
X-ray emitting black hole in a globular cluster in the elliptical galaxy NGC
4472. The XMM-Newton spectrum of the source in its bright epoch is well
described by a multiple blackbody model with a characteristic temperature
$kT_{in}\approx$ 0.2 keV. The spectrum of an archival Chandra observation of
the source obtained 3.5 years before the XMM data gives similar estimates for
the blackbody parameters. We confirm that the fainter interval of the
XMM-Newton observation has a spectrum that is consistent with the brighter
epoch, except for an additional level of foreground absorption. We also
consider other possible mechanisms for the variability. Based on the timescale
of the X-ray flux decline and the estimated size of the X-ray emission region
we argue that an eclipsing companion is highly unlikely. We find the most
likely means of producing the absorption changes on the observed timescale is
through partial obscuration by a precessing warped accretion disk.


title:
Unitary Correlation Operator Method and Similarity Renormalization
  Group: Connections and Differences

abstract:
  We discuss relations and differences between two methods for the construction
of unitarily transformed effective interactions, the Similarity Renormalization
Group (SRG) and Unitary Correlation Operator Method (UCOM). The aim of both
methods is to construct a soft phase-shift equivalent effective interaction
which is well suited for many-body calculations in limited model spaces. After
contrasting the two conceptual frameworks, we establish a formal connection
between the initial SRG-generator and the static generators of the UCOM
transformation. Furthermore we propose a mapping procedure to extract UCOM
correlation functions from the SRG evolution. We compare the effective
interactions resulting from the UCOM-transformation and the SRG-evolution on
the level of matrix elements, in no-core shell model calculations of light
nuclei, and in Hartree-Fock calculations up to 208-Pb. Both interactions
exhibit very similar convergence properties in light nuclei but show a
different systematic behavior as function of particle number.


title: Resummations in QCD hard-scattering at large and small x

abstract:
  We discuss different resummations of large logarithms that arise in
hard-scattering cross sections of quarks and gluons in regions of large and
small x. The large-x logarithms are typically dominant near threshold for the
production of a specified final state. These soft and collinear gluon
corrections produce large enhancements of the cross section for many processes,
notably top quark and Higgs production, and typically the higher-order
corrections reduce the factorization and renormalization scale dependence of
the cross section. The small-x logarithms are dominant in the regime where the
momentum transfer of the hard sub-process is much smaller than the total
collision energy. These logarithms are important to describe multijet final
states in deep inelastic scattering and hadron colliders, and in the study of
parton distribution functions. The resummations at small and large x are linked
by the eikonal approximation and are dominated by soft gluon anomalous
dimensions. We will review their role in both contexts and provide some
explicit calculations at one and two loops.


title: Raman scattering in a d-wave superconductor - a one gap scenario

abstract:
  Recent Raman scattering data in B_{1g} and B_{2g} geometries in the
superconducting state of underdoped cuprates were interpreted as evidence for
two distinct energy gaps. We argue that these data can be equally well
explained within a one gap scenario if final state interactions are taken into
account. In particular, we show that they can account for the differing doping
dependences of the Raman peaks in these two geometries.


title: Note on Integer Factoring Methods IV

abstract:
  This note continues the theoretical development of deterministic integer
factorization algorithms based on systems of polynomials equations. The main
result establishes a new deterministic time complexity bench mark in integer
factorization.


title: Bare and dressed particles in collision theory

abstract:
  The bare-dressed technique is, for the first time, used in collision theory.
The approach is valid for classical as well for quantum binary elastic
collisions in the non relativistic regime. The same formalism can be used for
inelastic collisions, when the particles undergo only a change of their
internal quantum states during the collision process. All kinematic results can
be obtained by a simple matrix transformation. Moreover, to make also simple
and clear the results, for the inelastic collisions, the restitution
coefficient formulation of inelastic processes has been used.


title: Call Admission Control Algorithm for pre-stored VBR video streams

abstract:
  We examine the problem of accepting a new request for a pre-stored VBR video
stream that has been smoothed using any of the smoothing algorithms found in
the literature. The output of these algorithms is a piecewise constant-rate
schedule for a Variable Bit-Rate (VBR) stream. The schedule guarantees that the
decoder buffer does not overflow or underflow. The problem addressed in this
paper is the determination of the minimal time displacement of each new
requested VBR stream so that it can be accomodated by the network and/or the
video server without overbooking the committed traffic. We prove that this
call-admission control problem for multiple requested VBR streams is
NP-complete and inapproximable within a constant factor, by reducing it from
the VERTEX COLOR problem. We also present a deterministic morphology-sensitive
algorithm that calculates the minimal time displacement of a VBR stream
request. The complexity of the proposed algorithm make it suitable for
real-time determination of the time displacement parameter during the call
admission phase.


title:
VINE -- A numerical code for simulating astrophysical systems using
  particles I: Description of the physics and the numerical methods

abstract:
  We present a Fortran 95 code for simulating the evolution of astrophysical
systems using particles to represent the underlying fluid flow. The code is
designed to be versatile, flexible and extensible, with modular options that
can be selected either at compile time or at run time. We include a number of
general purpose modules describing a variety of physical processes commonly
required in the astrophysical community. The code can be used as an N-body code
to evolve a set of particles in two or three dimensions using either a Leapfrog
or Runge-Kutta-Fehlberg integrator, with or without individual timesteps for
each particle. Particles may interact gravitationally as $N$-body particles,
and all or any subset may also interact hydrodynamically, using the Smoothed
Particle Hydrodynamic (SPH) method. Massive point particles (`stars') which may
accrete nearby SPH or $N$-body particles may also be included. The default free
boundary conditions can be replaced by a module to include periodic boundaries.
Cosmological expansion may also be included. An interface with special purpose
`GRAPE' hardware may also be selected. If available, forces obtained from the
GRAPE coprocessors may be transparently substituted for those obtained from the
default tree based calculation. The code may be run without modification on
single processors or in parallel using OpenMP compiler directives on large
scale, shared memory parallel machines. In comparison to the Gadget-2 code of
Springel 2005, the gravitational force calculation is $\approx 3.5 - 4.8$ times
faster with VINE when run on 8 Itanium~2 processors in an SGI Altix, while
producing nearly identical outcomes in our test problems. We present
simulations of several test problems, including a merger simulation of two
elliptical galaxies with 800000 particles.


title:
Physical realization of coupled Hilbert-space mirrors for quantum-state
  engineering

abstract:
  Manipulation of superpositions of discrete quantum states has a mathematical
counterpart in the motion of a unit-length statevector in an N-dimensional
Hilbert space. Any such statevector motion can be regarded as a succession of
two-dimensional rotations. But the desired statevector change can also be
treated as a succession of reflections, the generalization of Householder
transformations. In multidimensional Hilbert space such reflection sequences
offer more efficient procedures for statevector manipulation than do sequences
of rotations. We here show how such reflections can be designed for a system
with two degenerate levels - a generalization of the traditional two-state atom
- that allows the construction of propagators for angular momentum states. We
use the Morris-Shore transformation to express the propagator in terms of
Morris-Shore basis states and Cayley-Klein parameters, which allows us to
connect properties of laser pulses to Hilbert-space motion. Under suitable
conditions on the couplings and the common detuning, the propagators within
each set of degenerate states represent products of generalized Householder
reflections, with orthogonal vectors. We propose physical realizations of this
novel geometrical object with resonant, near-resonant and far-off-resonant
laser pulses. We give several examples of implementations in real atoms or
molecules.


title: Numerical study of entanglement entropy in SU(2) lattice gauge theory

abstract:
  The entropy of entanglement between a three-dimensional slab of thickness l
and its complement is studied numerically for four-dimensional SU(2) lattice
gauge theory. We find a signature of a nonanalytic behavior of the entanglement
entropy, which was predicted recently for large N_c confining gauge theories in
the framework of AdS/CFT correspondence. The derivative of the entanglement
entropy over l is likely to have a discontinuity at some l = l_c. It is argued
that such behavior persists even at finite temperatures, probably turning into
a sort of crossover for temperatures larger than the temperature of the
deconfinement phase transition. We also confirm that the entanglement entropy
contains quadratically divergent l-independent term, and that the nondivergent
terms behave as the inverse square of l at small distances.


title: Coexistence of qubit effects

abstract:
  We characterize all coexistent pairs of qubit effects. This gives an
exhaustive description of all pairs of events allowed, in principle, to occur
in a single qubit measurement. The characterization consists of three disjoint
conditions which are easy to check for a given pair of effects. Known special
cases are shown to follow from our general characterization theorem.


title:
Geometrical origin of entropy during inflation from the STM theory of
  gravity

abstract:
  Using a recently introduced 5D Riemann flat metric, we investigate the
possibility of introducing dissipation in the dynamics of the inflaton field on
an effective 4D FRW metric, in the framework of the STM theory of gravity.


title:
Experimental investigation of the ratchet effect in a two-dimensional
  electron system with broken spatial inversion symmetry

abstract:
  We report on experimental evidence of directed electron transport, induced by
external linear-polarized microwave irradiation, in a two-dimensional
spatially-periodic asymmetrical system called ratchet. The broken spatial
symmetry was introduced in a high mobility two-dimensional electron gas based
on AlGaAs/GaAs heterojunction, by patterning an array of artificial
semi-discs-shaped antidots. We show that the direction of the transport is
efficiently changed by microwave polarization. The dependence of the effect on
magnetic field and temperature is investigated. This represents a significant
step towards the realization of new microwave detectors and current generators.


title: Gravitational lensing of transient neutrino sources by black holes

abstract:
  In this work we study gravitational lensing of neutrinos by Schwarzschild
black holes. In particular, we analyze the case of a neutrino transient source
associated with a gamma-ray burst lensed by a supermassive black hole located
at the center of an interposed galaxy. We show that the primary and secondary
images have an angular separation beyond the resolution of forthcoming km-scale
detectors, but the signals from each image have time delays between them that
in most cases are longer than the typical duration of the intrinsic events. In
this way, the signal from different images can be detected as separate events
coming from the very same location in the sky. This would render an event that
otherwise might have had a low signal-to-noise ratio a clear detection, since
the probability of a repetition of a signal from the same direction is
negligible. The relativistic images are so faint and proximate that are beyond
the sensitivity and resolution of the next-generation instruments.


title: Global Birkhoff coordinates for the periodic Toda lattice

abstract:
  In this paper we prove that the periodic Toda lattice admits globally defined
Birkhoff coordinates.


title:
VINE -- A numerical code for simulating astrophysical systems using
  particles II: Implementation and performance characteristics

abstract:
  We continue our presentation of VINE. We begin with a description of relevant
architectural properties of the serial and shared memory parallel computers on
which VINE is intended to run, and describe their influences on the design of
the code itself. We continue with a detailed description of a number of
optimizations made to the layout of the particle data in memory and to our
implementation of a binary tree used to access that data for use in
gravitational force calculations and searches for SPH neighbor particles. We
describe modifications to the code necessary to obtain forces efficiently from
special purpose `GRAPE' hardware. We conclude with an extensive series of
performance tests, which demonstrate that the code can be run efficiently and
without modification in serial on small workstations or in parallel using
OpenMP compiler directives on large scale, shared memory parallel machines. We
analyze the effects of the code optimizations and estimate that they improve
its overall performance by more than an order of magnitude over that obtained
by many other tree codes. Scaled parallel performance of the gravity and SPH
calculations, together the most costly components of most simulations, is
nearly linear up to maximum machine sizes available to us (120 processors on an
Origin~3000). At similar accuracy, performance of VINE, used in GRAPE-tree
mode, is approximately a factor two slower than that of VINE, used in host-only
mode. Optimizations of the GRAPE/host communications could improve the speed by
as much as a factor of three, but have not yet been implemented in VINE.


title:
Coherent pulsed excitation of degenerate multistate systems: Exact
  analytic solutions

abstract:
  We show that the solution of a multistate system composed of N degenerate
lower (ground) states and one upper (excited) state can be reduced by using the
Morris-Shore transformation to the solution of a two-state system involving
only the excited state and a (bright) superposition of ground states. In
addition, there are N-1 dark states composed of ground states. We use this
decomposition to derive analytical solutions for degenerate extensions of the
most popular exactly soluble models: the resonance solution, the Rabi,
Landau-Zener, Rosen-Zener, Allen-Eberly and Demkov-Kunike models. We suggest
various applications of the multistate solutions, for example, as tools for
creating multistate coherent superpositions by generalized resonant pi-pulses.
We show that such generalized pi-pulses can occur even when the upper state is
far off resonance, at special detunings, which makes it possible to operate in
the degenerate ground-state manifold without populating the (possibly lossy)
upper state, even transiently.


title: The quadratic character experiment

abstract:
  A fast new algorithm is used compute the zeros of the quadratic character
L-functions for all negative fundamental discriminants with absolute value
10^12<d<10^12+10^7. These are compared to the 1-level density, including
various lower order terms. These terms come from, on the one hand the Explicit
Formula, and on the other the L-functions Ratios Conjecture. The latter give a
much better fit to the data, providing numerical evidence for the conjecture.


title:
Tuning the gap in bilyaer graphene using chemical functionalization: DFT
  calculations

abstract:
  Opening, in a controllable way, the energy gap in the electronic spectrum of
graphene is necessary for many potential applications, including an efficient
carbon-based transistor. We have shown that this can be achieved by chemical
functionalization of bilayer graphene. Using various dopants, such as H, F, Cl,
Br, OH, CN, CCH, NH2, COOH, and CH3 one can vary the gap smoothly between 0.64
and 3 eV and the state with the energy gap is stable corresponding to the
lowest-energy configurations. The peculiarities of the structural properties of
bilayer graphene in comparison with bulk graphite are discussed.


title:
Some remarks on the Einstein and M{\o}ller pseudotensors for static and
  spherically-symmetric configurations

abstract:
  It is shown that for the spherically-symmetric and static systems the
hypotheses posed by Yang and Radinschi and by Vagenas can be related to the
particular distribution of the source. Simple proofs are given and a number of
examples are discussed with the special emphasis put on the quantum corrected
Schwarzschild black hole.


title: Measurement of the Bc meson mass in the exclusive decay Bc --> Jpsi Pi

abstract:
  A fully reconstructed Bc --> Jpsi Pi signal is observed with the D0 detector
at the Fermilab Tevatron p-pbar collider. Using 1.3 inverse femtobarns of
integrated luminosity, the signal is extracted with a significance more than
five standard deviations above background. The measured Bc meson mass is 6300
(+-) 14 (stat) (+-) 5 (sys) MeV/cc


title:
Molecular Systems with Infinite and Finite Degrees of Freedom. Part I:
  Multi-Scale Analysis

abstract:
  The paper analyses stochastic systems describing reacting molecular systems
with a combination of two types of state spaces, a finite-dimensional, and an
infinite dimenional part. As a typical situation consider the interaction of
larger macro-molecules, finite and small in numbers per cell (like protein
complexes), with smaller, very abundant molecules, for example metabolites. We
study the construction of the continuum approximation of the associated Master
Equation (ME) by using the Trotter approximation [27]. The continuum limit
shows regimes where the finite degrees of freedom evolve faster than the
infinite ones. Then we develop a rigourous asymptotic adiabatic theory upon the
condition that the jump process arising from the finite degrees of freedom of
the Markov Chain (MC, typically describing conformational changes of the
macro-molecules) occurs with large frequency. In a second part of this work,
the theory is applied to derive typical enzyme kinetics in an alternative way
and interpretation within this framework.


title: Hypercontractivity for log-subharmonic functions

abstract:
  We prove strong hypercontractivity (SHC) inequalities for logarithmically
subharmonic functions on $\RR^n$ and different classes of measures: Gaussian
measures on $\RR^n$, symmetric Bernoulli and symmetric uniform probability
measures on $\RR$, as well as their convolutions. Surprisingly, a slightly
weaker strong hypercontractivity property holds for {\em any} symmetric measure
on $\RR$. For all measures on $\R$ for which we know the (SHC) holds, we prove
that a log--Sobolev inequality holds in the log-subharmonic category with a
constant {\em smaller} than the one for Gaussian measure in the classical
context. This result is extended to all dimensions for compactly-supported
measures.


title:
Near-threshold Z-pair production in the semi-phenomenological model of
  unstable particles

abstract:
  Near-threshold production of neutral boson pairs is considered within the
framework of the model of unstable particles with smeared mass. The results of
calculations are in good agreement with LEP II data and Monte-Carlo
simulations.


title:
A Cosmology-Independent Calibration of Gamma-Ray Burst Luminosity
  Relations and the Hubble Diagram

abstract:
  An important concern in the application of gamma-ray bursts (GRBs) to
cosmology is that the calibration of GRB luminosity/energy relations depends on
the cosmological model, due to the lack of a sufficient low-redshift GRB
sample. In this paper, we present a new method to calibrate GRB relations in a
cosmology-independent way. Since objects at the same redshift should have the
same luminosity distance and since the distance moduli of Type Ia supernovae
(SNe Ia) obtained directly from observations are completely cosmology
independent, we obtain the distance modulus of a GRB at a given redshift by
interpolating from the Hubble diagram of SNe Ia. Then we calibrate seven GRB
relations without assuming a particular cosmological model and construct a GRB
Hubble diagram to constrain cosmological parameters. From the 42 GRBs at
$1.4<z\le6.6$, we obtain $\Omega_{\rm M}=0.25_{-0.05}^{+0.04}$,
$\Omega_{\Lambda}=0.75_{-0.04}^{+0.05}$ for the flat $\Lambda$CDM model, and
for the dark energy model with a constant equation of state
$w_0=-1.05_{-0.40}^{+0.27}$, which is consistent with the concordance model in
a 1-$\sigma$ confidence region.


title:
Proton-proton correlations observed in two-proton decay of $^{19}$Mg and
  $^{16}$Ne

abstract:
  Proton-proton correlations were observed for the two-proton decays of the
ground states of $^{19}$Mg and $^{16}$Ne. The trajectories of the respective
decay products, $^{17}$Ne+p+p and $^{14}$O+p+p, were measured by using a
tracking technique with microstrip detectors. These data were used to
reconstruct the angular correlations of fragments projected on planes
transverse to the precursor momenta. The measured three-particle correlations
reflect a genuine three-body decay mechanism and allowed us to obtain
spectroscopic information on the precursors with valence protons in the $sd$
shell.


title: Action in a fractal universe and the holographic upper bound

abstract:
  The basic scaling laws for structures in a fractal universe require that the
characteristic quantity of action associated with astronomical bodies should be
of order near the maximum possible action allowed by the holographic upper
bound. That conclusion is consistent with the observed parameters of galaxies
and clusters.


title:
Prevalence of Tidal Interactions among Local Seyfert Galaxies: The
  Control Experiment

abstract:
  We test whether there is a relation between the observed tidal interactions
and Seyfert activity by imaging in HI twenty inactive galaxies at the same
spatial resolution and detection threshold as the Seyfert sample. This control
sample of inactive galaxies were closely matched in Hubble type, range in size
and inclination, and have roughly comparable galaxy optical luminosity to the
Seyfert galaxies. We find that only ~15% of the galaxies in our control sample
are disturbed in HI, whereas the remaining ~85% show no disturbances whatsoever
in HI. Even at a spatial resolution of ~10 kpc, none of the latter galaxies
show appreciable HI disturbances reminiscent of tidal features.
  In a companion paper (Kuo et al. 2008), we report results from the first
systematic imaging survey of Seyfert galaxies in atomic hydrogen (HI) gas. We
find that only ~28% of the eighteen Seyfert galaxies in that sample are visibly
disturbed in optical starlight. By contrast, ~94% of the same Seyfert galaxies
are disturbed spatially and usually also kinematically in HI gas on galactic
scales of >~20 kpc. In at least ~67% and up to perhaps ~94% of cases, the
observed disturbances can be traced to tidal interactions with neighboring
galaxies detected also in HI. The dramatic contrast between the observed
prevalence of HI disturbances in the Seyfert and control samples implicates
tidal interactions in initiating events that lead to luminous Seyfert activity
in a large fraction of local disk galaxies.


title: Group action on bimodule categories

abstract:
  We study group action on bimodules and bimodule categories and prove for them
analogues of the results known for representations of skew group algebras,
mainly in the case, when the action is separable.


title:
Model of response spectrum and modal interaction in coupled
  nanomechanical resonators

abstract:
  We develop a simple continuum model to analyze the vibrational modes of a
nanomechanical multi-element structure. In this model, arrays of sub-micron
cantilevers located symmetrically on both sides of the central clamped-clamped
nanobeam are replaced by a continuum. In this approach, the punctual shear
forces exerted by the cantilevers on the central beam are smoothed out and the
equations of motion of the structure become exactly solvable. Our analytical
results capture the main features of the vibrational modes observed both
numerically and experimentally. Furthermore, using a perturbative approach to
treat the nonlinear dynamics of the structure, we establish its
frequency-amplitude response and analyze the mechanism of anharmonic coupling
between two specific widely spaced modes of the resonator.


title:
Temperature Dependence of the Frequency and Noise of Superconducting
  Coplanar Waveguide Resonators

abstract:
  We present measurements of the temperature and power dependence of the
resonance frequency and frequency noise of superconducting niobium thin-film
coplanar waveguide resonators, carried out at temperatures well below the
superconducting transition (T_{c}=9.2 K). The noise decreases by nearly two
orders of magnitude as the temperature is increased from 120 to 1200 mK, while
the variation of the resonance frequency with temperature over this range
agrees well with the standard two-level system (TLS) model for amorphous
dielectrics. These results support the hypothesis that TLS are responsible for
the noise in superconducting microresonators, and have important implications
for resonator applications such as qubits and photon detectors.


title: On pseudo-Hermitian operators with generalized $\mathcal{C}$-symmetries

abstract:
  The concept of $\mathcal{C}$-symmetries for pseudo-Hermitian Hamiltonians is
studied in the Krein space framework. A generalization of
$\mathcal{C}$-symmetries is suggested.


title: Propagation Rules of Subsystem Codes

abstract:
  We demonstrate propagation rules of subsystem code constructions by
extending, shortening and combining given subsystem codes. Given an
$[[n,k,r,d]]_q$ subsystem code, we drive new subsystem codes with parameters
$[[n+1,k,r,\geq d]]_q$, $[[n-1,k+1,r,\geq d-1]]_q$, $[[n,k-1,r+1,d]]_q$. The
interested readers shall consult our companion papers for upper and lower
bounds on subsystem codes parameters, and introduction, trading dimensions,
families, and references on subsystem codes [1][2][3] and references therein.


title:
Anisotropic modification of the effective hole $g$-factor by
  electrostatic confinement

abstract:
  We investigate effects of lateral confinement on spin splitting of energy
levels in 2D hole gases grown on [311] GaAs. We found that lateral confinement
enhances anisotropy of spin splitting relative to the 2D gas for both confining
directions. Unexpectedly, the effective $g$-factor does not depend on the 1D
energy level number $N$ for $B\|[0\bar{1}1]$ while it has strong $N$-dependence
for $B\|[\bar{2}33]$. Apart from quantitative difference in the spin splitting
of energy levels for the two orthogonal confinement directions we also report
qualitative differences in the appearance of spin-split plateaus, with
non-quantized plateaus observed only for the confinement in $[0\bar{1}1]$
direction. In our samples we can clearly associate the difference with
anisotropy of spin-orbit interactions.


title: On the dynamics of certain homoclinic tangles

abstract:
  In this paper we study homoclinic tangles formed by transversal intersections
of the stable and the unstable manifold of a {\it non-resonant, dissipative}
homoclinic saddle point in periodically perturbed second order equations. We
prove that the dynamics of these homoclinic tangles are that of {\it infinitely
wrapped horseshoe maps}. Using $\mu$ as a parameter representing the magnitude
of the perturbations, we prove that (a) there exist infinitely many disjoint
open intervals of $\mu$, accumulating at $\mu = 0$, such that the entire
homoclinic tangle of the perturbed equation consists of one single horseshoe of
infinitely many symbols, (b) there are parameters in between each of these
parameter intervals, such that the homoclinic tangle contains attracting
periodic solutions, and (c) there are also parameters in between where the
homoclinic tangles admit non-degenerate transversal homoclinic tangency of
certain dissipative hyperbolic periodic solutions. In particular, (c) implies
the existence of strange attractors with SRB measures for a positive measure
set of parameters.


title:
Chromium at High Pressures: Weak Coupling and Strong Fluctuations in an
  Itinerant Antiferromagnet

abstract:
  The spin- and charge-density-wave order parameters of the itinerant
antiferromagnet chromium are measured directly with non-resonant x-ray
diffraction as the system is driven towards its quantum critical point with
high pressure using a diamond anvil cell. The exponential decrease of the spin
and charge diffraction intensities with pressure confirms the harmonic scaling
of spin and charge, while the evolution of the incommensurate ordering vector
provides important insight into the difference between pressure and chemical
doping as means of driving quantum phase transitions. Measurement of the charge
density wave over more than two orders of magnitude of diffraction intensity
provides the clearest demonstration to date of a weakly-coupled, BCS-like
ground state. Evidence for the coexistence of this weakly-coupled ground state
with high-energy excitations and pseudogap formation above the ordering
temperature in chromium, the charge-ordered perovskite manganites, and the blue
bronzes, among other such systems, raises fundamental questions about the
distinctions between weak and strong coupling.


title: Loop Quantum Cosmology: Effective theories and oscillating universes

abstract:
  Despite its great successes in accounting for the current observations, the
so called `standard' model of cosmology faces a number of fundamental
unresolved questions. Paramount among these are those relating to the nature of
the origin of the universe and its early evolution. Regarding the question of
origin, the main difficulty has been the fact that within the classical general
relativistic framework, the `origin' is almost always a singular event at which
the laws of physics break down, thus making it impossible for such an event, or
epochs prior to it, to be studied. Recent studies have shown that Loop Quantum
Cosmology may provide a non-singular framework where these questions can be
addressed. The crucial role here is played by quantum effects, i.e.\
corrections to the classical equations of motion, which are incorporated in
effective equations employed to develop cosmological scenarios.
  In this chapter we shall consider the three main types of quantum effects
expected to be present within such a framework and discuss some of their
consequences for the effective equations. In particular we discuss how such
corrections can allow the construction of non-singular emergent scenarios for
the origin of the universe, which are past-eternal, oscillating and naturally
emerge into an inflationary phase. These scenarios provide a physically
plausible picture for the origin and early phases of the universe, which is in
principle testable. We pay special attention to the interplay between these
different types of correction terms. Given the absence, so far, of a complete
derivation of such corrections in general settings, it is important to bear in
mind the questions of consistency and robustness of scenarios based on partial
inclusion of such effects.


title: Bright solitary waves of trapped atomic Bose-Einstein condensates

abstract:
  Motivated by recent experimental observations, we study theoretically
multiple bright solitary waves of trapped Bose-Einstein condensates. Through
variational and numerical analyses, we determine the threshold for collapse of
these states. Under $\pi$-phase differences between adjacent waves, we show
that the experimental states lie consistently at the threshold for collapse,
where the corresponding in-phase states are highly unstable. Following the
observation of two long-lived solitary waves in a trap, we perform detailed
three-dimensional simulations which confirm that in-phase waves undergo
collapse while a $\pi$-phase difference preserves the long-lived dynamics and
gives excellent quantitative agreement with experiment. Furthermore,
intermediate phase differences lead to the growth of population asymmetries
between the waves, which ultimately triggers collapse.


title: Fermion- and Spin-Counting in Strongly Correlated Systems

abstract:
  We apply the atom counting theory to strongly correlated Fermi systems and
spin models, which can be realized with ultracold atoms. The counting
distributions are typically sub-Poissonian and remain smooth at quantum phase
transitions, but their moments exhibit critical behavior, and characterize
quantum statistical properties of the system. Moreover, more detailed
characterizations are obtained with experimentally feasible spatially resolved
counting distributions.


title:
A new method to integrate (2+1)-wave equations with Dirac's delta
  functions as sources

abstract:
  Unlike in the Schwarzschild black hole background, gravitational
perturbations in a Kerr black hole background can not be decomposed into simple
tensor harmonics in the time domain. Here, we make mode decompositions only in
the azimuthal direction. As a first step, we discuss the resulting
(2+1)-dimensional Klein-Gordon differential equation for scalar perturbations
with a two dimensional Dirac's $\delta$-function as a source representing a
point particle orbiting a much larger black hole. To make this equation
amenable for numerical integrations we explicitly remove analytically the
singular behavior of the source and compute a global, well bahaved, effective
source for the corresponding waveform.


title: The Case for Dynamic Models of Learners' Ontologies in Physics

abstract:
  In a series of well-known papers, Chi and Slotta (Chi, 1992; Chi & Slotta,
1993; Chi, Slotta & de Leeuw, 1994; Slotta, Chi & Joram, 1995; Chi, 2005;
Slotta & Chi, 2006) have contended that a reason for students' difficulties in
learning physics is that they think about concepts as things rather than as
processes, and that there is a significant barrier between these two
ontological categories. We contest this view, arguing that expert and novice
reasoning often and productively traverses ontological categories. We cite
examples from everyday, classroom, and professional contexts to illustrate
this. We agree with Chi and Slotta that instruction should attend to learners'
ontologies; but we find these ontologies are better understood as dynamic and
context-dependent, rather than as static constraints. To promote one
ontological description in physics instruction, as suggested by Slotta and Chi,
could undermine novices' access to productive cognitive resources they bring to
their studies and inhibit their transition to the dynamic ontological
flexibility required of experts.


title:
Molecular Systems with Infinite and Finite Degrees of Freedom. Part II:
  Deterministic Dynamics and Examples

abstract:
  In this paper we consider deterministic limits of molecular stochastic
systems with finite and infinite degrees of freedom. The method to obtain the
deterministic vector field is based on the continuum limit of such microscopic
systems which has been derived in [11]. With the aid of the theory we finally
develop a new approach for molecular systems that describe typical enzyme
kinetics or other interactions between molecular machines like genetic elements
and smaller communicating molecules. In contrast to the literature on enzyme
kinetics the resulting deterministic functional responses are not derived by
time-scale arguments on the macroscopic level, but are a result of time scaling
transition rates on the discrete microscopic level. We present several examples
of common functional responses found in the literature, like Michaelis-Menten
and Hill equation. We finally give examples of more complex but typical
macro-molecular machinery.


title:
Exterior differential systems, Lie algebra cohomology, and the rigidity
  of homogenous varieties

abstract:
  These are expository notes from the 2008 Srni Winter School. They have two
purposes: (1) to give a quick introduction to exterior differential systems
(EDS), which is a collection of techniques for determining local existence to
systems of partial differential equations, and (2) to give an exposition of
recent work (joint with C. Robles) on the study of the Fubini-Griffiths-Harris
rigidity of rational homogeneous varieties, which also involves an advance in
the EDS technology.


title: On the dynamics of a time-periodic equation

abstract:
  In this paper we use the second order equation $\frac{d^2 q}{dt^2} + (\lambda
- \gamma q^2) \frac{d q}{dt} - q + q^3 = \mu q^2 \sin \omega t$ as a
demonstrative example to illustrate how to apply the analysis of \cite{WO} and
\cite{WOk} to the studies of concrete equations. We prove, among many other
things, that there are positive measure sets of parameters $(\lambda, \gamma,
\mu, \omega)$ corresponding to the case of intersected and the case of
separated stable and unstable manifold of the solution $q(t) = 0$, $t \in
\mathbb R$ respectively, so that the corresponding equations admit strange
attractors with SRB measures.


title:
Distributed Opportunistic Scheduling For Ad-Hoc Communications Under
  Noisy Channel Estimation

abstract:
  Distributed opportunistic scheduling is studied for wireless ad-hoc networks,
where many links contend for one channel using random access. In such networks,
distributed opportunistic scheduling (DOS) involves a process of joint channel
probing and distributed scheduling. It has been shown that under perfect
channel estimation, the optimal DOS for maximizing the network throughput is a
pure threshold policy. In this paper, this formalism is generalized to explore
DOS under noisy channel estimation, where the transmission rate needs to be
backed off from the estimated rate to reduce the outage. It is shown that the
optimal scheduling policy remains to be threshold-based, and that the rate
threshold turns out to be a function of the variance of the estimation error
and be a functional of the backoff rate function. Since the optimal backoff
rate is intractable, a suboptimal linear backoff scheme that backs off the
estimated signal-to-noise ratio (SNR) and hence the rate is proposed. The
corresponding optimal backoff ratio and rate threshold can be obtained via an
iterative algorithm. Finally, simulation results are provided to illustrate the
tradeoff caused by increasing training time to improve channel estimation at
the cost of probing efficiency.


title: Dissipative homoclinic loops and rank one chaos

abstract:
  We prove that when subjected to periodic forcing of the form $p_{\mu, \rh,
\om} (t) = \mu (\rh h(x,y) + \sin (\om t))$, certain second order systems of
differential equations with dissipative homoclinic loops admit strange
attractors with SRB measures for a set of forcing parameters $(\mu, \rh, \om)$
of positive measure. Our proof applies the recent theory of rank one maps,
developed by Wang and Young based on the analysis of strongly dissipative
H\'enon maps by Benedicks and Carleson.


title: Distributed Opportunistic Scheduling for MIMO Ad-Hoc Networks

abstract:
  Distributed opportunistic scheduling (DOS) protocols are proposed for
multiple-input multiple-output (MIMO) ad-hoc networks with contention-based
medium access. The proposed scheduling protocols distinguish themselves from
other existing works by their explicit design for system throughput improvement
through exploiting spatial multiplexing and diversity in a {\em distributed}
manner. As a result, multiple links can be scheduled to simultaneously transmit
over the spatial channels formed by transmit/receiver antennas. Taking into
account the tradeoff between feedback requirements and system throughput, we
propose and compare protocols with different levels of feedback information.
Furthermore, in contrast to the conventional random access protocols that
ignore the physical channel conditions of contending links, the proposed
protocols implement a pure threshold policy derived from optimal stopping
theory, i.e. only links with threshold-exceeding channel conditions are allowed
for data transmission. Simulation results confirm that the proposed protocols
can achieve impressive throughput performance by exploiting spatial
multiplexing and diversity.


title: Modular functionals and perturbations of Nakano spaces

abstract:
  We settle several questions regarding the model theory of Nakano spaces left
open by the PhD thesis of Pedro Poitevin \cite{Poitevin:PhD}. We start by
studying isometric Banach lattice embeddings of Nakano spaces, showing that in
dimension two and above such embeddings have a particularly simple and rigid
form. We use this to show show that in the Banach lattice language the modular
functional is definable and that complete theories of atomless Nakano spaces
are model complete. We also show that up to arbitrarily small perturbations of
the exponent Nakano spaces are $\aleph_0$-categorical and $\aleph_0$-stable. In
particular they are stable.


title: Definability of groups in $\aleph_0$-stable metric structures

abstract:
  We prove that in a continuous $\aleph_0$-stable theory every type-definable
group is definable. The two main ingredients in the proof are:
\begin{enumerate} \item Results concerning Morley ranks (i.e., Cantor-Bendixson
ranks) from \cite{BenYaacov:TopometricSpacesAndPerturbations}, allowing us to
prove the theorem in case the metric is invariant under the group action; and
\item Results concerning the existence of translation-invariant definable
metrics on type-definable groups and the extension of partial definable metrics
to total ones. \end{enumerate}


title: Delayed (sudden) birth of entanglement

abstract:
  The concept of time delayed creation of entanglement by the dissipative
process of spontaneous emission is investigated. A threshold effect for the
creation of entanglement is found that the initially unentangled qubits can be
entangled after a finite time despite the fact that the coherence between the
qubits exists for all times. This delayed creation of entanglement, that we
call sudden birth of entanglement, is opposite to the currently extensively
discussed sudden death of entanglement and is characteristic for transient
dynamics of one-photon entangled states of the system. We determine the
threshold time for the creation of entanglement and find that it is related to
time at which the antisymmetric state remains the only excited state being
populated. It is shown that the threshold time can be controlled by the
distance between the qubits and the direction of initial excitation relative to
the interatomic axis. This effect suggests a new alternative for the study of
entanglement and provides an interesting resource for creation on demand of
entanglement between two qubits.


title:
The 2dF-SDSS LRG and QSO survey: evolution of the clustering of luminous
  red galaxies since z = 0.6

abstract:
  We present an analysis of the small-to-intermediate scale clustering of
samples of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey and
the 2dF-SDSS LRG and QSO (2SLAQ) survey carefully matched to have the same
rest-frame colours and luminosity. We study the spatial two-point
auto-correlation function in both redshift-space and real-space of a combined
sample of over 10,000 LRGs, which represent the most massive galaxies in the
universe with stellar masses > 10^11 h^-1 M_sun and space densities 10^-4 h^-3
Mpc^-3. We find no significant evolution in the amplitude r_0 of the
correlation function with redshift, but do see a slight decrease in the slope
with increasing redshift over 0.19 < z < 0.55 and scales of 0.32 < r < 32 h^-1
Mpc. We compare our measurements with the predicted evolution of dark matter
clustering and use the halo model to interpret our results. We find that our
clustering measurements are inconsistent (>99.9% significance) with a passive
model whereby the LRGs do not merge with one another; a model with a merger
rate of 7.5 +/- 2.3% from z = 0.55 to z = 0.19 (i.e. an average rate of 2.4%
Gyr^-1) provides a better fit to our observations. Our clustering and number
density measurements are consistent with the hypothesis that the merged LRGs
were originally central galaxies in different haloes which, following the
merger of these haloes, merged to create a single Brightest Cluster Galaxy. In
addition, we show that the small-scale clustering signal constrains the scatter
in halo merger histories. When combined with measurements of the luminosity
function, our results suggest that this scatter is sub-Poisson. While this is a
generic prediction of hierarchical models, it has not been tested before.


title: Quantum critical transport in clean graphene

abstract:
  We describe electrical transport in ideal single-layer graphene at zero
applied bias. There is a crossover from collisionless transport at frequencies
larger than k_B T/hbar (T is the temperature) to collision-dominated transport
at lower frequencies. The d.c. conductivity is computed by the solution of a
quantum Boltzmann equation. Due to a logarithmic singularity in the collinear
scattering amplitude (a consequence of relativistic dispersion in two
dimensions) quasi-particles and -holes moving in the same direction tend to an
effective equilibrium distribution whose parameters depend on the direction of
motion. This property allows us to find the non-equilibrium distribution
functions and the quantum critical conductivity exactly to leading order in
1/|ln(alpha)| where alpha is the coupling constant characterizing the Coulomb
interactions.


title: Accurate Mass Determinations in Decay Chains with Missing Energy

abstract:
  Many beyond the Standard Model theories include a stable dark matter
candidate that yields missing / invisible energy in collider detectors. If
observed at the Large Hadron Collider, we must determine if its mass and other
properties (and those of its partners) predict the correct dark matter relic
density. We give a new procedure for determining its mass with small error.


title:
Opportunistic Scheduling and Beamforming for MIMO-OFDMA Downlink Systems
  with Reduced Feedback

abstract:
  Opportunistic scheduling and beamforming schemes with reduced feedback are
proposed for MIMO-OFDMA downlink systems. Unlike the conventional beamforming
schemes in which beamforming is implemented solely by the base station (BS) in
a per-subcarrier fashion, the proposed schemes take advantages of a novel
channel decomposition technique to perform beamforming jointly by the BS and
the mobile terminal (MT). The resulting beamforming schemes allow the BS to
employ only {\em one} beamforming matrix (BFM) to form beams for {\em all}
subcarriers while each MT completes the beamforming task for each subcarrier
locally. Consequently, for a MIMO-OFDMA system with $Q$ subcarriers, the
proposed opportunistic scheduling and beamforming schemes require only one BFM
index and $Q$ supportable throughputs to be returned from each MT to the BS, in
contrast to $Q$ BFM indices and $Q$ supportable throughputs required by the
conventional schemes. The advantage of the proposed schemes becomes more
evident when a further feedback reduction is achieved by grouping adjacent
subcarriers into exclusive clusters and returning only cluster information from
each MT. Theoretical analysis and computer simulation confirm the effectiveness
of the proposed reduced-feedback schemes.


title:
Strong Lensing in Abell 1703: Constraints on the Slope of the Inner Dark
  Matter Distribution

abstract:
  In this article, we apply strong lensing techniques in Abell 1703, a massive
X-ray luminous galaxy cluster at z=0.28. Our analysis is based on imaging data
both from space and ground in 8 bands, complemented with a spectroscopic
survey. Abell 1703 looks rather circular from the general shape of its multiply
imaged systems and present a dominant giant elliptical cD galaxy in its centre.
This cluster exhibits a remarkable bright 'central ring' formed by 4 bright
images at z_{spec}=0.888 located very close to the cD galaxy, providing
observational constraints that are potentially very interesting to probe the
central mass distribution. The stellar contribution from the cD galaxy (~1.25
10^{12} M_{sun} within 7") is accounted for in our parametric mass modelling,
and the underlying smooth dark matter component distribution is described using
a generalized NFW profile parametrized with a central logarithmic slope \alpha.
We find that within the range where observational constraints are present (from
~5" to ~50"), the slope of the dark matter distribution in Abell1703 is equal
to 1.09^{+0.05}_{-0.11} (3\sigma confidence level). The concentration parameter
is equal to c_{200} ~ 3.5, and the scale radius is constrained to be larger
than the region where observational constraints are available. Within this
radius, the 2D mass is equal to M(50")=2.4 10^{14} M_{\sun}. We cannot draw any
conclusions on cosmological models at this point since we lack results from
realistic numerical simulations containing baryons to make a proper comparison.
We advocate the need for a sample of observed and simulated unimodal relaxed
galaxy clusters in order to make reliable comparisons, and potentially provide
a test of cosmological models.


title: Reduced Incidence algebras description of cobweb posets and KoDAGs

abstract:
  After identifying the reduced incidence algebra of an arbitrary cobweb poset
the very first properties of these algebras are being disclosed.


title: A measure-conjugacy invariant for free group actions

abstract:
  This paper introduces a new measure-conjugacy invariant for actions of free
groups. Using this invariant, it is shown that two Bernoulli shifts over a
finitely generated free group are measurably conjugate if and only if their
base measures have the same entropy. This answers a question of Ornstein and
Weiss.


title:
BDDC by a frontal solver and the stress computation in a hip joint
  replacement

abstract:
  A parallel implementation of the BDDC method using the frontal solver is
employed to solve systems of linear equations from finite element analysis, and
incorporated into a standard finite element system for engineering analysis by
linear elasticity. Results of computation of stress in a hip replacement are
presented. The part is made of titanium and loaded by the weight of human body.
The performance of BDDC with added constraints by averages and with added
corners is compared.


title: Update on g-mode research

abstract:
  Since the beginning of this century we have attended a blooming of the
gravity-mode research thanks to the unprecedented quality of the data
available, either from space with SoHO, or from the ground-based networks as
BiSON or GONG. From the first upper limit of the gravity-mode amplitudes fixed
at 10 mm/s at 200 microHz given by Appourchaux et al. (2000), on one hand, a
peak was supposed to be a component of the l=1, n=1 mixed mode (Garcia et al.
2001a, b; Gabriel et al. 2002) and, on the other hand, a couple of patterns
--multiplets-- were attributed to gravity modes (Turck-Chieze et al. 2004;
Mathur et al. 2007). One of these patterns, found around 220 microHz, could be
labeled as the l=2, n =-3 g mode, which is expected to be the one with the
highest surface amplitude (Cox and Guzik 2004). Finally, in 2007, Garcia et al.
were able to measure the fingertips of the dipole gravity modes looking for
their asymptotic properties. In the present paper we present an update of the
recent developments on this subject with special attention to the 220 microHz
region, the dipole asymptotic properties and the impact of the incoming g-mode
observations on the knowledge of the solar structure and rotation profile.


title:
An XMM-Newton study of the environments, particle content and impact of
  low-power radio galaxies

abstract:
  We present a detailed study of the environments of a sample of nine low-power
radio galaxies, based on new and archival XMM-Newton observations. We report
new detections of group-scale environments around three radio galaxies, 3C 296,
NGC 1044 and 3C 76.1. As with previous studies, we find that FR-I radio
galaxies inhabit group environments ranging over nearly two orders of magnitude
in bolometric X-ray luminosity, but find no evidence for a tight relationship
between large-scale X-ray environment and radio-source properties such as size,
radio luminosity, and axial ratio. We confirm earlier work showing that
equipartition internal pressures are typically lower than the external
pressures acting on the radio lobes, so that additional non-radiating particles
must be present or the lobes must be magnetically dominated. We present the
first direct observational evidence that entrainment may provide this missing
pressure, in the form of a relationship between radio-source structure and
apparent pressure imbalance. Finally, our study provides further support for
the presence of an apparent temperature excess in radio-loud groups compared to
the group population as a whole. For five of eight temperature excesses, the
energy required to inflate the radio lobes is comparable to the energy required
to produce this excess by heating of the group gas; however, in three cases the
current radio source appears too weak to produce the temperature excess. It
remains unclear whether the temperature excess can be directly associated with
the current phase of AGN activity, or whether it is instead either a signature
of previous AGN activity or simply an indicator of the particular set of group
properties most conducive to the growth of an FR-I radio galaxy.


title:
Nonlocal operator basis from the path representation of the M(k+1,k+2)
  and the M(k+1,2k+3) minimal models

abstract:
  We reinterpret a path describing a state in an irreducible module of the
unitary minimal model M(k+1,k+2) in terms of a string of charged operators
acting on the module's ground-state path. Each such operator acts non-locally
on a path. The path characteristics are then translated into a set of
conditions on sequences of operators that provide an operator basis. As an
application, we re-derive the vacuum finite fermionic character by constructing
the generating function of these basis states.
  These results generalize directly to the M(k+1,2k+3) models, the close
relatives of the unitary models in terms of path description.


title:
SINR Analysis of Opportunistic MIMO-SDMA Downlink Systems with Linear
  Combining

abstract:
  Opportunistic scheduling (OS) schemes have been proposed previously by the
authors for multiuser MIMO-SDMA downlink systems with linear combining. In
particular, it has been demonstrated that significant performance improvement
can be achieved by incorporating low-complexity linear combining techniques
into the design of OS schemes for MIMO-SDMA. However, this previous analysis
was performed based on the effective signal-to-interference ratio (SIR),
assuming an interference-limited scenario, which is typically a valid
assumption in SDMA-based systems. It was shown that the limiting distribution
of the effective SIR is of the Frechet type. Surprisingly, the corresponding
scaling laws were found to follow $\epsilon\log K$ with $0<\epsilon<1$, rather
than the conventional $\log\log K$ form.
  Inspired by this difference between the scaling law forms, in this paper a
systematic approach is developed to derive asymptotic throughput and scaling
laws based on signal-to-interference-noise ratio (SINR) by utilizing extreme
value theory. The convergence of the limiting distribution of the effective
SINR to the Gumbel type is established. The resulting scaling law is found to
be governed by the conventional $\log\log K$ form. These novel results are
validated by simulation results. The comparison of SIR and SINR-based analysis
suggests that the SIR-based analysis is more computationally efficient for
SDMA-based systems and it captures the asymptotic system performance with
higher fidelity.


title: The Kashiwara-Vergne conjecture and Drinfeld's associators

abstract:
  The Kashiwara-Vergne (KV) conjecture is a property of the Campbell-Hausdorff
series put forward in 1978. It has been settled in the positive by E.
Meinrenken and the first author in 2006. In this paper, we study the uniqueness
issue for the KV problem. To this end, we introduce a family of infinite
dimensional groups KV_n, and an extension \hat{KV}_2 of the group KV_2. We show
that the group \hat{KV}_2 contains the Grothendieck-Teichmueller group GRT as a
subgroup, and that it acts freely and transitively on the set of solutions of
the KV problem Sol(KV). Furthermore, we prove that Sol(KV) is isomorphic to a
direct product of a line \k (\k being a field of characteristic zero) and the
set of solutions of the pentagon equation with values in the group KV_3. The
latter contains the set of Drinfeld's associators as a subset. As a by-product,
we obtain a new proof of the Kashiwara-Vergne conjecture based on the
Drinfeld's theorem on existence of associators.


title: A U(3)_C X U(3)_L X U(3)_R gauge symmetry from intersecting D-branes

abstract:
  A three-family non-supersymmetric model with U(3)^3 gauge symmetry is
analyzed in the context of intersecting D-branes. This is equivalent to the
`trinification' model extended by three U(1) factors which survive as global
symmetries in the low energy effective model. The Standard Model fermions are
accommodated in the three possible bifundamental multiplets represented by
strings with endpoints attached on different brane-stacks of this particular
setup. Further, a natural Quark-Lepton hierarchy is realized due to the
existence of the additional abelian symmetries


title: Frobenius splittings of toric varieties

abstract:
  We discuss a characteristic free version of Frobenius splittings for toric
varieties and give a polyhedral criterion for a toric variety to be diagonally
split. We apply this criterion to show that section rings of nef line bundles
on diagonally split toric varieties are normally presented and Koszul, and that
Schubert varieties are not diagonally split in general.


title: A new signature for color octet pseudoscalars at the LHC

abstract:
  Color octet (pseudo)scalars, if they exist, will be copiously produced at the
CERN Large Hadron Collider (LHC). However, their detection can become a very
challenging task. In particular, if their decay into a pair of top quarks is
kinematically forbidden, the main decay channel would be into two jets, with a
very large background. In this Brief Report we explore the possibility of using
anomaly-induced decays of the color octet pseudoscalars into gauge bosons to
find them at the LHC.


title: Group Actions and Covering Maps in the Uniform Category

abstract:
  In Rips Complexes and Covers in the Uniform Category (arXiv:0706.3937) we
define, following James, covering maps of uniform spaces and introduce the
concept of generalized uniform covering maps. In this paper we investigate when
these covering maps are induced by group actions. Also, as an application of
our results we present an exposition of Prajs' homogeneous curve that is
path-connected but not locally connected.


title: Geodesic Motion on Closed Spaces: Two Numerical Examples

abstract:
  The geodesic structure is very closely related to the trace of the Laplace
operator, involved in the calculation of the expectation value of the energy
momentum tensor in Universes with non trivial topology. The purpose of this
work is to provide concrete numerical examples of geodesic flows. Two manifolds
with genus $g=0$ are given. In one the chaotic regions, form sets of negligible
or zero measure. In the second example the geodesic flow, shows the presence of
measurable chaotic regions. The approach is "experimental", numerical, and
there is no attempt to an analytical calculation.


title: Degree and valuation of the Schur elements of cyclotomic Hecke algebras

abstract:
  Following the generalization of the notion of families of characters, defined
by Lusztig for Weyl groups, to the case of complex reflection groups, thanks to
the definition given by Rouquier, we show that the degree and the valuation of
the Schur elements (functions A and a) remain constant on the "families" of the
cyclotomic Hecke algebras of the exceptional complex reflection groups. The
same result has already been obtained for the groups of the infinite series and
for some special cases of exceptional groups.


title:
A O(n^8) X O(n^7) Linear Programming Model of the Quadratic Assignment
  Problem

abstract:
  This paper has been withdrawn because Theorem 21 and Corollary 22 are in
error; The modeling idea is OK, but it needs 9-dimensional variables instead of
the 8-dimensional variables defined in notations 6.9.
  Examples of the correct model (with 9-index variables) are: (1) Diaby, M.,
"Linear Programming Formulation of the Set Partitioning Problem," International
Journal of Operational Research 8:4 (August 2010) pp. 399-427; (2) Diaby, M.,
"Linear Programming Formulation of the Vertex Coloring Problem," International
Journal of Mathematics in Operational Research 2:3 (May 2010) pp. 259-289; (3)
Diaby, M., "The Traveling Salesman Problem: A Linear Programming Formulation,"
WSEAS Transactions on Mathematics, 6:6 (June 2007) pp. 745-754.


title: On types for unramified p-adic unitary groups

abstract:
  Folloing the methods of Bushnell-Kutzko for general linear groups, we
construct simple types attached to certain skew simple strata for a symplectic
group and an unramified unitary group over a non-archimedean local field.


title: Macroscopic superposition states in rotating ring lattices

abstract:
  We investigate the effects of rotation on one-dimensional ultracold bosons
confined to optical ring lattices. First, we show that there exists a critical
rotation frequency at which the ground state of a weakly-interacting and
integer-filled atomic gas is fragmented into a macroscopic superposition state
with different circulation. Second, we point out several advantages of using
slightly non-uniform ring lattices. Finally, we demonstrate that different
quasi-momentum states can be distinguished in time-of-flight absorption imaging
and propose to probe correlations via the many-body oscillations induced by a
sudden change in the rotation frequency.


title:
The Mandelstam-Terning Line Integral in Unparticle Physics -- A Reply to
  Galloway, Martin and Stancato

abstract:
  We show that the path ordered Wilson line integral used in 0802.0313 to make
a nonlocal action gauge invariant is mathematically inconsistent. We also show
that it can lead to reasonable gauge field vertexes by the use of a second
mathematically unjustifiable procedure.


title:
Multistep Bayesian strategy in coin-tossing games and its application to
  asset trading games in continuous time

abstract:
  We study multistep Bayesian betting strategies in coin-tossing games in the
framework of game-theoretic probability of Shafer and Vovk (2001). We show that
by a countable mixture of these strategies, a gambler or an investor can
exploit arbitrary patterns of deviations of nature's moves from independent
Bernoulli trials. We then apply our scheme to asset trading games in continuous
time and derive the exponential growth rate of the investor's capital when the
variation exponent of the asset price path deviates from two.


title: Curves That Must Be Retraced

abstract:
  We exhibit a polynomial time computable plane curve GAMMA that has finite
length, does not intersect itself, and is smooth except at one endpoint, but
has the following property. For every computable parametrization f of GAMMA and
every positive integer n, there is some positive-length subcurve of GAMMA that
f retraces at least n times. In contrast, every computable curve of finite
length that does not intersect itself has a constant-speed (hence
non-retracing) parametrization that is computable relative to the halting
problem.


title: Vortices on closed surfaces

abstract:
  We consider $N$ point vortices $s_j$ of strengths $\kappa_j$ moving on a
closed (compact, boundaryless, orientable) surface $S$ with riemannian metric
$g$. As far as we know, only the sphere or surfaces of revolution, the latter
qualitatively, have been treated in the available literature. The aim of this
note is to present an intrinsic geometric formulation for the general case. We
give a simple proof of Kimura's conjecture that a dipole describes geodesic
motion. Searching for integrable vortex pairs systems on Liouville surfaces is
in order. The vortex pair system on a triaxial ellipsoid extends Jacobi's
geodesics. Is it Arnold-Liouville integrable? Not in our wildest dreams is
another possibility: that quantizing a vortex system could relate with a
million dollars worth question, but we took courage - nerve is more like it -
to also present it.


title:
Identifying phases of quantum many-body systems that are universal for
  quantum computation

abstract:
  Quantum computation can proceed solely through single-qubit measurements on
an appropriate quantum state, such as the ground state of an interacting
many-body system. We investigate a simple spin-lattice system based on the
cluster-state model, and by using nonlocal correlation functions that quantify
the fidelity of quantum gates performed between distant qubits, we demonstrate
that it possesses a quantum (zero-temperature) phase transition between a
disordered phase and an ordered "cluster phase" in which it is possible to
perform a universal set of quantum gates.


title:
Giant Phonon-induced Conductance in Scanning Tunneling Spectroscopy of
  Gate-tunable Graphene

abstract:
  The honeycomb lattice of graphene is a unique two-dimensional (2D) system
where the quantum mechanics of electrons is equivalent to that of relativistic
Dirac fermions. Novel nanometer-scale behavior in this material, including
electronic scattering, spin-based phenomena, and collective excitations, is
predicted to be sensitive to charge carrier density. In order to probe local,
carrier-density dependent properties in graphene we have performed
atomically-resolved scanning tunneling spectroscopy measurements on
mechanically cleaved graphene flake devices equipped with tunable back-gate
electrodes. We observe an unexpected gap-like feature in the graphene tunneling
spectrum which remains pinned to the Fermi level (E_F) regardless of graphene
electron density. This gap is found to arise from a suppression of electronic
tunneling to graphene states near E_F and a simultaneous giant enhancement of
electronic tunneling at higher energies due to a phonon-mediated inelastic
channel. Phonons thus act as a "floodgate" that controls the flow of tunneling
electrons in graphene. This work reveals important new tunneling processes in
gate-tunable graphitic layers.


title:
Estimation of Domain Size in Nano Ferroelectrics from NMR T1
  Measurements

abstract:
  The spin lattice relaxation of I=3/2 quadrupolar spin system due to domain
walls in order-disorder ferroelectrics has been studied and a general method is
proposed for the measurement of domain width in nano ferroelectrics. Based on
the fact that electric polarization undergoes spiral orientation as one moves
from one domain to the other, it is assumed that at low temperatures the spins
at and near domain walls undergo relaxation due to possible easy reorientation
of electric polarization in domain walls even though such a relaxation in the
main body of the domain has almost ceased. The spins present inside the domain
undergo relaxation through transfer of magnetization to the domain walls
through a spin diffusion process by nearest neighbour interaction. Rate
equations for spin populations are formed by representing the ferroelectric
domain by a one-dimensional chain of equidistant spins having dipolar coupling.
Spin populations are calculated as a function of time for different ratios of
quadrupolar to dipolar transition probabilities for a sample subjected to
selective rf pulse. Expression for spin- lattice relaxation time T1 is derived
in terms of domain width and ratio of quadrupolar to dipolar transition
probabilities. It is found that the domain width can be estimated provided the
value of spin lattice relaxation time T1 is known for the corresponding crystal
with normal sized grains. The results are quite general and can be applied to
any order disorder ferroelectric with nano sized domains and having spin I=3/2
nuclei.


title:
Bayesball: A Bayesian hierarchical model for evaluating fielding in
  major league baseball

abstract:
  The use of statistical modeling in baseball has received substantial
attention recently in both the media and academic community. We focus on a
relatively under-explored topic: the use of statistical models for the analysis
of fielding based on high-resolution data consisting of on-field location of
batted balls. We combine spatial modeling with a hierarchical Bayesian
structure in order to evaluate the performance of individual fielders while
sharing information between fielders at each position. We present results
across four seasons of MLB data (2002--2005) and compare our approach to other
fielding evaluation procedures.


title: Network Quotients: Structural Skeletons of Complex Systems

abstract:
  A defining feature of many large empirical networks is their intrinsic
complexity. However, many networks also contain a large degree of structural
repetition. An immediate question then arises: can we characterize essential
network complexity while excluding structural redundancy?
  In this article we utilize inherent network symmetry to collapse all
redundant information from a network, resulting in a coarse-graining which we
show to carry the essential structural information of the `parent' network. In
the context of algebraic combinatorics, this coarse-graining is known as the
\emph{quotient}. We systematically explore the theoretical properties of
network quotients and summarize key statistics of a variety of `real-world'
quotients with respect to those of their parent networks. In particular, we
find that quotients can be substantially smaller than their parent networks yet
typically preserve various key functional properties such as complexity
(heterogeneity and hubs vertices) and communication (diameter and mean geodesic
distance), suggesting that quotients constitute the essential structural
skeleton of their parent network. We summarize with a discussion of potential
uses of quotients in analysis of biological regulatory networks and ways in
which using quotients can reduce the computational complexity of network
algorithms.


title: Determinant Expansions of Signed Matrices and of Certain Jacobians

abstract:
  This paper treats two topics: matrices with sign patterns and Jacobians of
certain mappings. The main topic is counting the number of plus and minus
coefficients in the determinant expansion of sign patterns and of these
Jacobians. The paper is motivated by an approach to chemical networks initiated
by Craciun and Feinberg. We also give a graph-theoretic test for determining
when the Jacobian of a chemical reaction dynamics has a sign pattern.