title:
CLUSTEREASY: A Program for Simulating Scalar Field Evolution on Parallel
  Computers

abstract:
  We describe a new, parallel programming version of the scalar field
simulation program LATTICEEASY. The new C++ program, CLUSTEREASY, can simulate
arbitrary scalar field models on distributed-memory clusters. The speed and
memory requirements scale well with the number of processors. As with the
serial version of LATTICEEASY, CLUSTEREASY can run simulations in one, two, or
three dimensions, with or without expansion of the universe, with customizable
parameters and output. The program and its full documentation are available on
the LATTICEEASY website at
http://www.science.smith.edu/departments/Physics/fstaff/gfelder/latticeeasy/.
In this paper we provide a brief overview of what CLUSTEREASY does and the ways
in which it does and doesn't differ from the serial version of LATTICEEASY.


title: Log-average periodogram estimator of the memory parameter

abstract:
  This paper introduces a semiparametric regression estimator of the memory
parameter for long-memory time series process. It is based on the regression in
a neighborhood of the zero-frequency of the periodogram averaged over epochs.
The proposed estimator is theoretically justified and empirical Monte Carlo
investigation gives evidence that the method is very promising to estimate the
long-memory parameter.


title: Primitivity of finitely presented monomial algebras

abstract:
  We study prime monomial algebras. Our main result is that a prime finitely
presented monomial algebra is either primitive or it has GK dimension one and
satisfies a polynomial identity. More generally, we show this result holds for
the class of \emph{automaton algebras}; that is, monomial algebras that have a
basis consisting of the set of words recognized by some finite state automaton.
This proves a special case of a conjecture of the first author and Agata
Smoktunowicz.


title:
The thickness of HI in galactic discs under MOND: theory and application
  to the Galaxy

abstract:
  The outskirts of galaxies are a very good laboratory for testing the nature
of the gravitational field at low accelerations. By assuming that the neutral
hydrogen gas is in hydrostatic equilibrium in the gravitational potential of
the host galaxy, the observed flaring of the gas layer can be used to test
modified gravities. For the first time we construct a simple framework to
derive the scaleheight of the neutral hydrogen gas disc in the MOND scenario
and apply this to the Milky Way. It is shown that using a constant gas velocity
dispersion of ~9 km/s, MOND is able to give a very good fit to the observed HI
flaring beyond a galactocentric distance of 17 kpc up to the last measured
point (~40 kpc). Between 10 and 16 kpc, however, the observed scaleheight is
about 40% more than what MOND predicts for the standard interpolating function
and 70% for the form suggested by Famaey & Binney. Given the uncertainties in
the non-thermal pressure support by cosmic rays and magnetic fields, MOND seems
to be a plausible alternative to dark matter in explaining the Milky Way
flaring. Studying the flaring of extended HI discs in external edge-on galaxies
may be a promising approach to assess the viability of MOND.


title:
Loop quantization of spherically symmetric midi-superspaces : the
  interior problem

abstract:
  We continue the study of spherically symmetric vacuum space-times in loop
quantum gravity by treating the interior of a black hole. We start from a
midi-superspace approach, but a simple gauge fixing leads to a Kantowski--Sachs
form for the variables. We show that one can solve the quantum theory exactly
in the (periodic) connection representation, including the inner product. The
evolution can be solved exactly by de-parameterizing the theory and can be
easily interpreted as a semi-classical evolution plus quantum corrections. A
relational evolution can also be introduced in a precise manner, suggesting
what may happen in situations where it is not possible to de-parameterize. We
show that the singularity is replaced by a bounce at which quantum effects are
important and that the extent of the region at the bounce where one departs
from classical general relativity depends on the initial data.


title: Multiplicity of Codimension Three Almost Complete Intersections

abstract:
  We establish the upper bound in the multiplicity conjecture of Herzog, Huneke
and Srinivasan for the codimension three almost complete intersections. We also
give some partial results in the case where I is the aci linked to a complete
intersection in one step.


title: Spectra and semigroup smoothing for non-elliptic quadratic operators

abstract:
  We study non-elliptic quadratic differential operators. Quadratic
differential operators are non-selfadjoint operators defined in the Weyl
quantization by complex-valued quadratic symbols. When the real part of their
Weyl symbols is a non-positive quadratic form, we point out the existence of a
particular linear subspace in the phase space, intrinsically associated to the
Weyl symbols, called a singular space, such that when the singular space has a
symplectic structure, the associated heat semigroup is smoothing in every
direction of its symplectic orthogonal complement. When the Weyl symbol of such
an operator is elliptic on the singular space, this space is always symplectic
and we prove that the spectrum of the operator is discrete and can be described
as in the globally elliptic case. We also describe the large time behavior of
contraction semigroups generated by these operators.


title:
The epitaxial-graphene/graphene-oxide junction, an essential step
  towards epitaxial graphene electronics

abstract:
  Graphene oxide (GO) flakes have been deposited to bridge the gap between two
epitaxial graphene electrodes to produce all-graphene devices. Electrical
measurements indicate the presence of Schottky barriers (SB) at the
graphene/graphene oxide junctions, as a consequence of the band-gap in GO. The
barrier height is found to be about 0.7 eV, and is reduced after annealing at
180 $^\circ$C, implying that the gap can be tuned by changing the degree of
oxidation. A lower limit of the GO mobility was found to be 850 cm$^2$/Vs,
rivaling silicon. {\it In situ} local oxidation of patterned epitaxial graphene
has been achieved.


title: A General Relativistic Rotating Evolutionary Universe

abstract:
  We show that when we work with coordinate cosmic time, which is not proper
time, Robertson-Walker's metric, includes a possible rotational state of the
Universe. An exact formula for the angular speed and the temporal metric
coefficient, is found.


title: Condensation of Determinants

abstract:
  In this paper we tried to condense the determinant of n square matrix to the
determinant of (n - 1) square matrix with the mathematical proof.


title: Why are there so few hot Jupiters?

abstract:
  We use numerical simulations to model the migration of massive planets at
small radii and compare the results with the known properties of 'hot Jupiters'
(extrasolar planets with semi-major axes a < 0.1 AU). For planet masses Mp sin
i > 0.5 MJup, the evidence for any `pile-up' at small radii is weak
(statistically insignificant), and although the mass function of hot Jupiters
is deficient in high mass planets as compared to a reference sample located
further out, the small sample size precludes definitive conclusions. We suggest
that these properties are consistent with disc migration followed by entry into
a magnetospheric cavity close to the star. Entry into the cavity results in a
slowing of migration, accompanied by a growth in orbital eccentricity. For
planet masses in excess of 1 Jupiter mass we find eccentricity growth
timescales of a few x 10^5 years, suggesting that these planets may often be
rapidly destroyed. Eccentricity growth appears to be faster for more massive
planets which may explain changes in the planetary mass function at small radii
and may also predict a pile-up of lower mass planets, the sample of which is
still incomplete.


title: Thermal Balance in the Intracluster Medium: Is AGN Feedback Necessary?

abstract:
  A variety of physical heating mechanisms are combined with radiative cooling
to explore, via one dimensional hydrodynamic simulations, the expected thermal
properties of the intracluster medium (ICM) in the context of the cooling flow
problem. Energy injection from type Ia supernovae, thermal conduction, and
dynamical friction (DF) from orbiting satellite galaxies are considered. The
novel feature of this work is the exploration of a wide range of efficiencies
of each heating process. While the latter two can provide a substantial amount
of energy, neither mechanism operating alone can produce nor maintain an ICM in
thermal balance over cosmological timescales, in stark contrast with
observations. For simulated clusters with initially isothermal temperature
profiles, both mechanisms acting in combination result in long-term thermal
balance for a range of ICM temperatures and for central electron densities less
than n_e~0.02 cm^-3; at greater densities catastrophic cooling invariably
occurs. Furthermore, these heating mechanisms can neither produce nor maintain
clusters with a declining temperature profile in the central regions, implying
that the observed "cooling-core'' clusters, which have such declining
temperature profiles, cannot be maintained with these mechanisms alone. Thus,
while there appears to be an abundant supply of energy capable of heating the
ICM in clusters, it is extremely difficult for the energy deposition to occur
in such a way that the ICM remains in thermal balance over cosmological
time-scales. These results strongly suggest that a more dynamic heating process
such as feedback from a central black hole is required to generate the
properties of observed intracluster media. (ABRIDGED)


title:
Interaction effects in 2D electron gas in a random magnetic field:
  Implications for composite fermions and quantum critical point

abstract:
  We consider a clean two-dimensional interacting electron gas subject to a
random perpendicular magnetic field, h({\bf r}). The field is nonquantizing, in
the sense, that {\cal N}_h-a typical flux into the area \lambda_{\text{\tiny
F}}^2 in the units of the flux quantum (\lambda_{\text{\tiny F}} is the de
Broglie wavelength) is small, {\cal N}_h\ll 1. If the spacial scale, \xi, of
change of h({\bf r}) is much larger than \lambda_{\text{\tiny F}}, the
electrons move along semiclassical trajectories. We demonstrate that a weak
field-induced curving of the trajectories affects the interaction-induced
electron lifetime in a singular fashion: it gives rise to the correction to the
lifetime with a very sharp energy dependence. The correction persists within
the interval \omega \sim \omega_0= E_{\text{\tiny F}}{\cal N}_h^{2/3} much
smaller than the Fermi energy, E_{\text{\tiny F}}. It emerges in the third
order in the interaction strength; the underlying physics is that a small phase
volume \sim (\omega/E_{\text{\tiny F}})^{1/2} for scattering processes,
involving {\em two} electron-hole pairs, is suppressed by curving. Even more
surprising effect that we find is that {\em disorder-averaged} interaction
correction to the density of states, \delta\nu(\omega), exhibits {\em
oscillatory} behavior, periodic in \bigl(\omega/\omega_0\bigr)^{3/2}. In our
calculations of interaction corrections random field is incorporated via the
phases of the Green functions in the coordinate space. We discuss the relevance
of the new low-energy scale for realizations of a smooth random field in
composite fermions and in disordered phase of spin-fermion model of
ferromagnetic quantum criticality.


title: Possible optical detection of a fast, nearby radio pulsar PSR B1133+16

abstract:
  Aims: We performed deep optical observations of the field of an old,
fast-moving radio pulsar PSR B1133+16 in an attempt to detect its optical
counterpart and a bow shock nebula.
  Methods: The observations were carried out using the direct imaging mode of
  FORS1 at the ESO VLT/UT1 telescope in the B, R, and H_alpha bands. We also
used archival images of the same field obtained with the VLT in the B band and
with the Chandra/ACIS in X-rays.
  Results: In the B band we detected a faint (B=28.1+/-0.3) source that may be
the optical counterpart of PSR B1133+16, as it is positionally consistent with
the radio pulsar and with the X-ray counterpart candidate published earlier.
Its upper limit in the R band implies a color index B-R <0.5, which is
compatible with the index values for most pulsars identified in the optical
range. The derived optical luminosity and its ratio to the X-ray luminosity of
the candidate are consistent with expected values derived from a sample of
pulsars detected in both spectral domains. No Balmer bow shock was detected,
implying a low density of ambient matter around the pulsar. However, in the
X-ray and H_alpha images we found the signature of a trail extending ~4"-5"
behind the pulsar and coinciding with the direction of its proper motion. If
confirmed by deeper studies, this is the first time such a trail has been seen
in the optical and X-ray wavelengths.
  Conclusions: Further observations at later epochs are necessary to confirm
the identification of the pulsar by the candidate's proper motion measurements.


title:
Volume growth and the topology of manifolds with nonnegative Ricci
  curvature

abstract:
  Let $M^n$ be a complete, open Riemannian manifold with $\Ric \geq 0$. In
1994, Grigori Perelman showed that there exists a constant $\delta_{n}>0$,
depending only on the dimension of the manifold, such that if the volume growth
satisfies $\alpha_M := \lim_{r \to \infty} \frac{\Vol(B_p(r))}{\omega_n r^n}
\geq 1-\delta_{n}$, then $M^n$ is contractible. Here we employ the techniques
of Perelman to find specific lower bounds for the volume growth, $\alpha(k,n)$,
depending only on $k$ and $n$, which guarantee the individual $k$-homotopy
group of $M^n$ is trivial.


title: Models for the Formation of Massive Stars

abstract:
  The formation of massive stars is currently an unsolved problems in
astrophysics. Understanding the formation of massive stars is essential because
they dominate the luminous, kinematic, and chemical output of stars.
Furthermore, their feedback is likely to play a dominant role in the evolution
of molecular clouds and any subsequent star formation therein. Although
significant progress has been made observationally and theoretically, we still
do not have a consensus as to how massive stars form. There are two contending
models to explain the formation of massive stars, Core Accretion and
Competitive Accretion. They differ primarily in how and when the mass that
ultimately makes up the massive star is gathered. In the core accretion model,
the mass is gathered in a prestellar stage due to the overlying pressure of a
stellar cluster or a massive pre-cluster cloud clump. In contrast, competitive
accretion envisions that the mass is gathered during the star formation process
itself, being funneled to the centre of a stellar cluster by the gravitational
potential of the stellar cluster. Although these differences may not appear
overly significant, they involve significant differences in terms of the
physical processes involved. Furthermore, the differences also have important
implications in terms of the evolutionary phases of massive star formation, and
ultimately that of stellar clusters and star formation on larger scales. Here
we review the dominant models, and discuss prospects for developing a better
understanding of massive star formation in the future.


title:
Classical Spin Models with Broken Continuous Symmetry: Random Field
  Induced Order and Persistence of Spontaneous Magnetization

abstract:
  We consider a classical spin model, of two-dimensional spins, with continuous
symmetry, and investigate the effect of a symmetry breaking unidirectional
quenched disorder on the magnetization of the system. We work in the mean field
regime. We show, by numerical simulations and by perturbative calculations in
the low as well as in the high temperature limits, that although the continuous
symmetry of the magnetization is lost, the system still magnetizes, albeit with
a lower value as compared to the case without disorder. The critical
temperature at which the system starts magnetizing, also decreases with the
introduction of disorder. However, with the introduction of an additional
constant magnetic field, the component of magnetization in the direction that
is transverse to the disorder field increases with the introduction of the
quenched disorder. We discuss the same effects also for three-dimensional
spins.


title:
Design, construction and tests of a 3 GHz proton linac booster (LIBO)
  for cancer therapy

abstract:
  In the last ten years the use of proton beams in radiation therapy has become
a clinical tool for treatment of deep-seated tumours. LIBO is a RF compact and
low cost proton linear accelerator (SCL type) for hadrontherapy. It is
conceived by TERA Foundation as a 3 GHz Linac Booster, to be mounted downstream
of an existing cyclotron in order to boost the energy of the proton beam up to
200 MeV, needed for deep treatment (~25 cm) in the human body. With this
solution it is possible to transform a low energy commercial cyclotron,
normally used for eye melanoma therapy, isotope production and nuclear physics
research, into an accelerator for deep-seated tumours. A prototype module of
LIBO has been built and successfully tested with full RF power at CERN and with
proton beam at INFN Laboratori Nazionali del Sud (LNS) in Catania, within an
international collaboration between TERA Foundation, CERN, the Universities and
INFN groups of Milan and Naples. The mid-term aim of the project is the
technology transfer of the accumulated know-how to a consortium of companies
and to bring this novel medical tool to hospitals. The design, construction and
tests of the LIBO prototype are described in detail.


title:
Tunneling conductance in $s$- and d-wave superconductor-graphene
  junctions: Extended Blonder-Tinkham-Klapwijk formalism

abstract:
  We investigate the conductance spectra of a normal/superconductor graphene
junction using the extended Blonder-Tinkham-Klapwijk formalism, considering
pairing potentials that are both conventional (isotropic s-wave) and
unconventional (anisotropic d-wave). In particular, we study the full crossover
from normal to specular Andreev reflection without restricting ourselves to
special limits and approximations, thus expanding results obtained in previous
work. In addition, we investigate in detail how the conductance spectra are
affected if it is possible to induce an unconventional pairing symmetry in
graphene, for instance a d-wave order parameter. We also discuss the recently
reported conductance-oscillations that take place in normal/superconductor
graphene junctions, providing both analytical and numerical results.


title: First variation of the Log Entropy functional along the Ricci flow

abstract:
  In this note, we establish the first variation formula of the adjusted log
entropy functional $\mathcal Y_a$ introduced by Ye in \cite{Y2}. As a direct
consequence, we also obtain the monotonicity of $\mathcal Y_a$ along the Ricci
flow.


title: Projective equivalence of ideals in Noetherian integral domains

abstract:
  Let I be a nonzero proper ideal in a Noetherian integral domain R. In this
paper we establish the existence of a finite separable integral extension
domain A of R and a positive integer m such that all the Rees integers of IA
are equal to m. Moreover, if R has altitude one, then all the Rees integers of
J = Rad(IA) are equal to one and the ideals J^m and IA have the same integral
closure. Thus Rad(IA) = J is a projectively full radical ideal that is
projectively equivalent to IA. In particular, if R is Dedekind, then there
exists a Dedekind domain A having the following properties: (i) A is a finite
separable integral extension of R; and (ii) there exists a radical ideal J of A
and a positive integer m such that IA = J^m.


title:
The 2003 Nov 14 occultation by Titan of TYC 1343-1865-1. II. Analysis of
  light curves

abstract:
  We observed a stellar occultation by Titan on 2003 November 14 from La Palma
Observatory using ULTRACAM with three Sloan filters: u', g', and i' (358, 487,
and 758 nm, respectively). The occultation probed latitudes 2 degrees S and 1
degrees N during immersion and emersion, respectively. A prominent central
flash was present in only the i' filter, indicating wavelength-dependent
atmospheric extinction. We inverted the light curves to obtain six lower-limit
temperature profiles between 335 and 485 km (0.04 and 0.003 mb) altitude. The
i' profiles agreed with the temperature measured by the Huygens Atmospheric
Structure Instrument [Fulchignoni, M. et al., 2005. Nature 438, 785-791] above
415 km (0.01 mb). The profiles obtained from different wavelength filters
systematically diverge as altitude decreases, which implies significant
extinction in the light curves. Applying an extinction model [Elliot, J.L.,
Young, L.A., 1992. Astron. J. 103, 991-1015] gave the altitudes of line of
sight optical depth equal to unity: 396 +/- 7 km and 401 +/- 20 km (u'
immersion and emersion); 354 +/- 7 km and 387 +/- 7 km (g' immersion and
emersion); and 336 +/- 5 km and 318 +/- 4 km (i' immersion and emersion).
Further analysis showed that the optical depth follows a power law in
wavelength with index 1.3 +/- 0.2. We present a new method for determining
temperature from scintillation spikes in the occulting body's atmosphere.
Temperatures derived with this method are equal to or warmer than those
measured by the Huygens Atmospheric Structure Instrument. Using the highly
structured, three-peaked central flash, we confirmed the shape of Titan's
middle atmosphere using a model originally derived for a previous Titan
occultation [Hubbard, W.B. et al., 1993. Astron. Astrophys. 269, 541-563].


title: Universal dynamical conductance in graphite

abstract:
  We find experimentally that the optical sheet conductance of graphite per
graphene layer is very close to $(\pi/2)e^2/h$, which is the theoretically
expected value of dynamical conductance of isolated monolayer graphene. Our
calculations within the Slonczewski-McClure-Weiss model explain well why the
interplane hopping leaves the conductance of graphene sheets in graphite almost
unchanged for photon energies between 0.1 and 0.6 eV, even though it
significantly affects the band structure on the same energy scale. The f-sum
rule analysis shows that the large increase of the Drude spectral weight as a
function of temperature is at the expense of the removed low-energy optical
spectral weight of transitions between hole and electron bands.


title: Evolving localizations in reaction-diffusion cellular automata

abstract:
  We consider hexagonal cellular automata with immediate cell neighbourhood and
three cell-states. Every cell calculates its next state depending on the
integral representation of states in its neighbourhood, i.e. how many
neighbours are in each one state. We employ evolutionary algorithms to breed
local transition functions that support mobile localizations (gliders), and
characterize sets of the functions selected in terms of quasi-chemical systems.
Analysis of the set of functions evolved allows to speculate that mobile
localizations are likely to emerge in the quasi-chemical systems with limited
diffusion of one reagent, a small number of molecules is required for
amplification of travelling localizations, and reactions leading to stationary
localizations involve relatively equal amount of quasi-chemical species.
Techniques developed can be applied in cascading signals in nature-inspired
spatially extended computing devices, and phenomenological studies and
classification of non-linear discrete systems.


title: The Divisor Matrix, Dirichlet Series and SL(2,Z)

abstract:
  A representation of SL(2,Z) by integer matrices acting on the space of
analytic ordinary Dirichlet series is constructed, in which the standard
unipotent element acts as multiplication by the Riemann zeta function. It is
then shown that the Dirichlet series in the orbit of the zeta function are
related to it by algebraic equations.


title: Probing Noise in Flux Qubits via Macroscopic Resonant Tunneling

abstract:
  Macroscopic resonant tunneling between the two lowest lying states of a
bistable RF-SQUID is used to characterize noise in a flux qubit. Measurements
of the incoherent decay rate as a function of flux bias revealed a Gaussian
shaped profile that is not peaked at the resonance point, but is shifted to a
bias at which the initial well is higher than the target well. The r.m.s.
amplitude of the noise, which is proportional to the decoherence rate 1/T_2^*,
was observed to be weakly dependent on temperature below 70 mK. Analysis of
these results indicates that the dominant source of low frequency (1/f) flux
noise in this device is a quantum mechanical environment in thermal
equilibrium.


title:
Identification, Classifications, and Absolute Properties of 773
  Eclipsing Binaries Found in the TrES Survey

abstract:
  In recent years we have witnessed an explosion of photometric time-series
data, collected for the purpose of finding a small number of rare sources, such
as transiting extrasolar planets and gravitational microlenses. Once combed,
these data are often set aside, and are not further searched for the many other
variable sources that they undoubtedly contain. To this end, we describe a
pipeline that is designed to systematically analyze such data, while requiring
minimal user interaction. We ran our pipeline on a subset of the Trans-Atlantic
Exoplanet Survey dataset, and used it to identify and model 773 eclipsing
binary systems. For each system we conducted a joint analysis of its light
curve, colors, and theoretical isochrones. This analysis provided us with
estimates of the binary's absolute physical properties, including the masses
and ages of their stellar components, as well as their physical separations and
distances. We identified three types of eclipsing binaries that are of
particular interest and merit further observations. The first category includes
11 low-mass candidates, which may assist current efforts to explain the
discrepancies between the observation and the models of stars at the bottom of
the main-sequence. The other two categories include 34 binaries with eccentric
orbits, and 20 binaries with abnormal light curves. Finally, this uniform
catalog enabled us to identify a number of relations that provide further
constraints on binary population models and tidal circularization theory.


title: A Universal Kernel for Learning Regular Languages

abstract:
  We give a universal kernel that renders all the regular languages linearly
separable. We are not able to compute this kernel efficiently and conjecture
that it is intractable, but we do have an efficient $\eps$-approximation.


title:
Numerical Simulation of the Double Slit Interference with Ultracold
  Atoms

abstract:
  We present a numerical simulation of the double slit interference experiment
realized by F. Shimizu, K. Shimizu and H. Takuma with ultracold atoms. We show
how the Feynman path integral method enables the calculation of the
time-dependent wave function. Because the evolution of the probability density
of the wave packet just after it exits the slits raises the issue of the
interpreting the wave/particle dualism, we also simulate trajectories in the de
Broglie-Bohm interpretation.


title:
Environment and mass dependencies of galactic $\lambda$ spin parameter:
  cosmological simulations and observed galaxies compared

abstract:
  We use a sample of galaxies from the Sloan Digital Sky Survey (SDSS) to
search for correlations between the $\lambda$ spin parameter and the
environment and mass of galaxies. In order to calculate the total value of
$\lambda$ for each observed galaxy, we employed a simple model of the dynamical
structure of the galaxies, which allows a rough estimate of the value of
$\lambda$ using only readily obtainable observables from the luminous galaxies.
Use of a large volume-limited sample (upwards of 11,000) allows reliable
inferences of mean values and dispersions of $\lambda$ distributions. We find,
in agreement with some N-body cosmological simulations, no significant
dependence of $\lambda$ on the environmental density of the galaxies. For the
case of mass, our results show a marked correlation with $\lambda$, in the
sense that low-mass galaxies present both higher mean values of $\lambda$ and
associated dispersions, than high-mass galaxies. These results provide
interesting constrain on the mechanisms of galaxy formation and acquisition of
angular momentum, a valuable test for cosmological models.


title:
The Magic Angle "Mystery" in Electron Energy Loss Spectroscopy:
  Relativistic and Dielectric Corrections

abstract:
  Recently it has been demonstrated that a careful treatment of both
longitudinal and transverse matrix elements in electron energy loss spectra can
explain the mystery of relativistic effects on the {\it magic angle}. Here we
show that there is an additional correction of order $(Z\alpha)^2$ where $Z$ is
the atomic number and $\alpha$ the fine structure constant, which is not
necessarily small for heavy elements. Moreover, we suggest that macroscopic
electrodynamic effects can give further corrections which can break the
sample-independence of the magic angle.


title:
Reflected Brownian motion in a wedge: sum-of-exponential stationary
  densities

abstract:
  We give necessary and sufficient conditions for the stationary density of
semimartingale reflected Brownian motion in a wedge to be written as a finite
sum of terms of exponential product form. Relying on geometric ideas
reminiscent of the reflection principle, we give an explicit formula for the
density in such cases.


title: Macroscopic Resonant Tunneling in the Presence of Low Frequency Noise

abstract:
  We develop a theory of macroscopic resonant tunneling of flux in a
double-well potential in the presence of realistic flux noise with significant
low-frequency component. The rate of incoherent flux tunneling between the
wells exhibits resonant peaks, the shape and position of which reflect
qualitative features of the noise, and can thus serve as a diagnostic tool for
studying the low-frequency flux noise in SQUID qubits. We show, in particular,
that the noise-induced renormalization of the first resonant peak provides
direct information on the temperature of the noise source and the strength of
its quantum component.


title: ECoG observations of power-law scaling in the human cortex

abstract:
  We report the results of our search for power-law electrical signals in the
human brain, using subdural electrocorticographic recordings from the surface
of the cortex. The power spectral density (PSD) of these signals has the
power-law form $ P(f)\sim f^{-\chi} $ from 80 to 500 Hz. This scaling index
$\chi = 4.0\pm 0.1$ is universal, across subjects, area in the cortex, and
local neural activity levels. The shape of the PSD does not change with local
cortex activity, only its amplitude increases. We observe a knee in the spectra
at $f_0\simeq 70$ Hz, implying the existence of a characteristic time scale
$\tau=(2\pi f_0)^{-1}\simeq 2-4$ msec. For $f<f_0$ we find evidence for a
power-law with $\chi_L\simeq 2.0\pm 0.4$.


title: The Contribution of Halo White Dwarf Binaries to the LISA Signal

abstract:
  Galactic double white dwarfs were postulated as a source of confusion limited
noise for LISA, the future space-based gravitational wave observatory. Until
very recently, the Galactic population consisted of a relatively well studied
disk population, a somewhat studied smaller bulge population and a mostly
unknown, but potentially large halo population. It has been argued that the
halo population may produce a signal that is much stronger (factor of ~5 in
spectral amplitude) than the disk population. However, this surprising result
was not based on an actual calculation of a halo white dwarf population but was
derived on (i) the assumption that one can extrapolate the halo population
properties from those of the disk population and (ii) the postulated
(unrealistically) high number of white dwarfs in the halo. We perform the first
calculation of a halo white dwarf population using population synthesis models.
Our comparison with the signal arising from double white dwarfs in the Galactic
disk+bulge clearly shows that it is impossible for the double white dwarf halo
signal to exceed that of the rest of the Galaxy. Using microlensing results to
give an upper limit on the content of white dwarfs in the halo (~30 % baryonic
mass in white dwarfs), our predicted halo signal is a factor of 10 lower than
the disk+bulge signal. Even in the implausible case where all of the baryonic
halo mass is found in white dwarfs, the halo signal does not become comparable
to that of the disk+bulge, and thus would still have a negligible effect on the
detection of other LISA sources.


title: Ewens measures on compact groups and hypergeometric kernels

abstract:
  On unitary compact groups the decomposition of a generic element into product
of reflections induces a decomposition of the characteristic polynomial into a
product of factors. When the group is equipped with the Haar probability
measure, these factors become independent random variables with explicit
distributions. Beyond the known results on the orthogonal and unitary groups
(O(n) and U(n)), we treat the symplectic case. In U(n), this induces a family
of probability changes analogous to the biassing in the Ewens sampling formula
known for the symmetric group. Then we study the spectral properties of these
measures, connected to the pure Fisher-Hartvig symbol on the unit circle. The
associated orthogonal polynomials give rise, as $n$ tends to infinity to a
limit kernel at the singularity.


title:
Some open problems in random matrix theory and the theory of integrable
  systems

abstract:
  We describe a list of open problems in random matrix theory and integrable
systems which was presented at the conference ``Integrable Systems, Random
Matrices, and Applications'' at the Courant Institute in May 2006.


title: Singular Monopoles via the Nahm Transform

abstract:
  We present explicit expressions for the fields of a charge one BPS monopole
with two Dirac singularities. These are solutions of the nonlinear Bogomolny
equations with the gauge group U(2) or SO(3). We derive these expressions by
applying the technique of the Nahm transform. By exploring various limits we
find a number of other solutions.


title:
First measurement of the forward-backward charge asymmetry in top quark
  pair production

abstract:
  We present the first measurement of the integrated forward-backward charge
asymmetry in top-antitop quark pair (ttbar) production in proton-antiproton
collisions in the lepton plus jets final state. Using a b-jet tagging algorithm
and kinematic reconstruction assuming ttbar+X production and decay, a sample of
0.9fb-1 of data, collected by the D0 experiment at the Fermilab Tevatron
Collider, is used to measure the asymmetry for different jet multiplicities.
The result is also used to set upper limits on ttbar+X production via a Z'
resonance.


title: Lepton number violating mSUGRA and neutrino masses

abstract:
  We perform a quantitative study of neutrino phenomenology in the framework of
minimal supergravity (mSUGRA) with grand unified theory (GUT)-scale tri-linear
lepton number violation. We show that only two non-zero GUT scale lepton number
violating parameters and three charged lepton mixing angles are sufficient to
account for current neutrino oscillation data. This allows collider studies to
be performed in a manageable parameter space. We discuss some phenomenological
consequences of the models, including tuning issues.


title: Embedded, Accreting Disks in Massive Star Formation

abstract:
  Recent advances in our understanding of massive star formation have made
clear the important role of protostellar disks in mediating accretion. Here we
describe a simple, semi-analytic model for young, deeply embedded, massive
accretion disks. Our approach enables us to sample a wide parameter space of
stellar mass and environmental variables, providing a means to make predictions
for a variety of sources that next generation telescopes like ALMA and the EVLA
will observe. Moreover we include, at least approximately, multiple mechanisms
for angular momentum transport, a comprehensive model for disk heating and
cooling, and a realistic estimate for the angular momentum in the gas
reservoir. We make predictions for the typical sizes, masses, and temperatures
of the disks, and describe the role of gravitational instabilities in
determining the binarity fraction and upper mass cut-off.


title: Simulations on the electromechanical poling of ferroelectric ceramics

abstract:
  Based on the two-step-switching model, the process of electromechanical
poling of a ferroelectric ceramics is simulated. A difference of the remnant
polarizations between two poling protocols (mechanical stress is applied before
and after the application of poling field) is found from our simulations, which
is also observed in experiment. An explanation is given to illustrate why the
remnant polarization for the case that mechanical stress is loaded after the
application of electric field is larger than the case that mechanical stress is
loaded before the application of electric field. Our simulation results supply
a proof for the validity of the two-step-switching model in the
electromechanical poling of polycrystalline ferroelectric ceramics.


title:
Ab initio no-core shell model and microscopic reactions: recent
  achievements

abstract:
  We report on recent microscopic calculations of reaction properties based
upon the nuclear structure of the ab initio no-core shell model (NCSM).


title: The Strong and Gravitational Couplings of Knotted Solitons

abstract:
  We extend our earlier study of the electroweak interactions of quantum knots
to their gravitational and strong interactions. The knots are defined by
appropriate quantum groups and are intended to describe all knotted field
structures that conserve mass and spin, charge and hypercharge, as well as
color charge and color hypercharge. As sources of the gravitational fields the
knots are described as representations of the quantum group $SL_q(2)$ and as
sources of the electroweak and strong fields they are described by $SU_q(2)$.
When the point sources of the standard theory are replaced by the quantum
knots, the interaction terms of the new Lagrangian density acquire knot form
factors and the standard local gauge invariance is supplemented by an
additional global $U(1)\times U(1)$ invariance of the $SU_q(2)$ algebra.


title: On Zonal Jets in Oceans

abstract:
  We find that in parameter regimes relevant to the recently observed
alternating zonal jets in oceans, the formation of these jets can be explained
as due to an arrest of the turbulent inverse-cascade of energy by {\em free}
Rossby waves (as opposed to Rossby {\em basin} modes) and a subsequent
redirection of that energy into zonal modes. This mechanism, originally studied
in the context of alternating jets in Jovian atmospheres and two dimensional
turbulence in zonally-periodic configurations survives in spite of the presence
of the meridional boundaries in the oceanic context.


title:
Volume Reflection and Refraction of Relativistic Particles in Bent
  Crystals

abstract:
  The quasi-channeling of positive and negative relativistic particles in a
bent crystal is studied using the classical deflection function. It was shown
that the potential scattering in a central field of bounded ring-like
potentials may produce the ``reflected'' and ``refracted'' fractions of
scattered particles. For particles with positive charge the ``reflected''
fraction is mainly presented; at the same time we predict that for particles
with negative charge the ``refracted'' fraction should dominate. The effect of
``empty core'' for central scattering is also discussed. The average deflection
angles for volume ``reflection'' and ``refraction'' are derived for accepted
potential model of the crystal. The calculated average ``reflection'' angle is
in satisfactory agreement with recent experimental data \cite{ivanov_2006}


title:
Testing the nature of S0 galaxies using planetary nebula kinematics in
  NGC 1023

abstract:
  We investigate the manner in which lenticular galaxies are formed by studying
their stellar kinematics: an S0 formed from a fading spiral galaxy should
display similar cold outer disc kinematics to its progenitor, while an S0
formed in a minor merger should be more dominated by random motions. In a pilot
study to attempt to distinguish between these scenarios, we have measured the
planetary nebula (PN) kinematics of the nearby S0 system NGC 1023. Using the
Planetary Nebula Spectrograph, we have detected and measured the line-of-sight
velocities of 204 candidate PNe in the field of this galaxy. Out to
intermediate radii, the system displays the kinematics of a normal
rotationally-supported disc system. After correction of its rotational
velocities for asymmetric drift, the galaxy lies just below the spiral galaxy
Tully-Fisher relation, as one would expect for a fading system. However, at
larger radii the kinematics undergo a gradual but major transition to random
motion with little rotation. This transition does not seem to reflect a change
in the viewing geometry or the presence of a distinct halo component, since the
number counts of PNe follow the same simple exponential decline as the stellar
continuum with the same projected disc ellipticity out to large radii. The
galaxy's small companion, NGC 1023A, does not seem to be large enough to have
caused the observed modification either. This combination of properties would
seem to indicate a complex evolutionary history in either the transition to
form an S0 or in the past life of the spiral galaxy from which the S0 formed.
More data sets of this type from both spirals and S0s are needed in order to
definitively determine the relationship between these types of system.


title:
Mass Models for Low Surface Brightness Galaxies with High Resolution
  Optical Velocity Fields

abstract:
  We present high-resolution optical velocity fields from DensePak integral
field spectroscopy, along with derived rotation curves, for a sample of low
surface brightness galaxies. In the limit of no baryons, we fit the NFW and
pseudoisothermal halo models to the data and find the rotation curve shapes and
halo central densities to be better described by the isothermal halo. For those
galaxies with photometry, we present halo fits for three assumptions of the
stellar mass-to-light ratio. We find that the velocity contribution from the
baryons is significant enough in the maximum disk case that maximum disk and
the NFW halo are mutually exclusive. We find a substantial cusp mass excess at
the centers of the galaxies, with at least two times more mass expected in the
cuspy CDM halo than is allowed by the data. We also find that to reconcile the
data with LCDM, ~20 km/s noncircular motions are needed and/or the power
spectrum has a lower amplitude on the scales we probe.


title:
Effects of anisotropic in-plane strains on the phase diagram of
  BaxSr1-xTiO3 thin film

abstract:
  Based on Landau-Devonshire (LD) phenomenological theory, phase diagram of
epitaxial BST50/50 thin films on anisotropic in-plane strains is investigated.
Different from BaTiO3 thin films, the paraelectric phase appears under the
anisotropic misfit strains on BST50/50 thin films at the room temperature. The
pyroelectric property of the BST films is also calculated, we find that the
position of pyroelectric peak greatly depends on anisotropic misfit strains.
Keywords: anisotropic in-plane strains; BST thin films; phase diagram


title:
The correspondence between Tracy-Widom (TW) and Adler-Shiota-van
  Moerbeke (ASvM) approaches in random matrix theory: the Gaussian case

abstract:
  Two approaches (TW and ASvM) to derivation of integrable differential
equations for random matrix probabilities are compared. Both methods are
rewritten in such a form that simple and explicit relations between all TW
dependent variables and $\tau$-functions of ASvM are found, for the example of
finite size Gaussian matrices. Orthogonal function systems and Toda lattice are
seen as the core structure of both approaches and their relationship.


title: An Improved Error Bound for Gaussian Interpolation

abstract:
  An error bound for Gaussian Interpolation which is better than the current
exponential-type error bound is presented.


title: A New Error Bound for Shifted Surface Spline Interpolation

abstract:
  A New Error Bound for shifted surface spline interpolation is presented. This
error bound probably is the most powerful one up to now.


title:
Rigorous description of exchange-correlation energy of many-electron
  systems

abstract:
  With the eigenfunctional theory, we study a general interacting electron
system, and give a rigorous expression of its ground state energy which is
composed of two parts, one part is contributed by the non-interacting
electrons, and another one is represented by the correlation functions that are
controlled by the electron correlation. Moreover, according to the rigorous
expression of the ground state energy, an effective method beyond the local
density approximation of the density functional theory is proposed.


title: Alexander polynomials and hyperbolic volume of arborescent links

abstract:
  We realize a given (monic) Alexander polynomial by a (fibered) hyperbolic
arborescent knot and link of any number of components, and by infinitely many
such links of at least 4 components. As a consequence, a Mahler measure
minimizing polynomial, if it exists, is realized as the Alexander polynomial of
a fibered hyperbolic link of at least 2 components. For given polynomial, we
give also an upper bound on the minimal hyperbolic volume of knots/links, and
contrarily, construct knots of arbitrarily large volume, which are arborescent,
or have given free genus at least 2.


title:
On Non-Relativistic Conformal Field Theory and Trapped Atoms: Virial
  Theorems and the State-Operator Correspondence in Three Dimensions

abstract:
  The field theory of nonrelativistic fermions interacting via contact
interactions can be used to calculate the properties of few-body systems of
cold atoms confined in harmonic traps. The state-operator correspondence of
Non-Relativistic Conformal Field Theory (NRCFT) shows that the energy
eigenvalues (in oscillator units) of N harmonically trapped fermions can be
calculated from the scaling dimensions of N-fermion operators in the NRCFT.
They are also in one-to-one correspondence with zero-energy, scale-invariant
solutions to the N-body problem in free space. We show that these two mappings
of the trapped fermion problem to free space problems are related by an
automorphism of the SL(2,R) algebra of the conformal symmetry of fermions at
the unitary limit. This automorphism exchanges the internal Hamiltonian of the
gas with the trapping potential and hence provides a novel method for deriving
virial theorems for trapped Fermi gases at the unitary limit. We also show that
the state-operator correspondence can be applied directly in three spatial
dimensions by calculating the scaling dimensions of two- and three-fermion
operators and finding agreement with known exact results for energy levels of
two and three trapped fermions at the unitary limit.


title: The geometry of thermodynamics

abstract:
  We present a review of the main aspects of geometrothermodynamics, an
approach which allows us to associate a specific Riemannian structure to any
classical thermodynamic system. In the space of equilibrium states, we consider
a Legendre invariant metric, which is given in terms of the fundamental
equation of the corresponding thermodynamic system, and analyze its geometric
properties in the case of the van der Waals gas, and black holes. We conclude
that the geometry of this particular metric reproduces the thermodynamic
behavior of the van der Waals gas, and the Reissner-Nordstr\"om black hole, but
it is not adequate for the thermodynamic description of Kerr black holes.


title: Quantum graphs with spin Hamiltonians

abstract:
  The article surveys quantization schemes for metric graphs with spin.
Typically quantum graphs are defined with the Laplace or Schrodinger operator
which describe particles whose intrinsic angular momentum (spin) is zero.
However, in many applications, for example modeling an electron (which has
spin-1/2) on a network of thin wires, it is necessary to consider operators
which allow spin-orbit interaction. The article presents a review of
quantization schemes for graphs with three such Hamiltonian operators, the
Dirac, Pauli and Rashba Hamiltonians. Comparing results for the trace formula,
spectral statistics and spin-orbit localization on quantum graphs with spin
Hamiltonians.


title:
Axi-symmetric Models of B[e] Supergiants: I. The Effective Temperature
  and Mass-loss Dependence of the Hydrogen and Helium Ionization Structure

abstract:
  We calculate the hydrogen and helium ionization in B[e] envelopes and explore
their dependence on mass-loss and effective temperature. We also present
simulated observations of the Halpha emission line and the C IV 1550 doublet,
and study their behavior. This paper reports our first results in an ongoing
study of B[e] supergiants, and provides a glimpse on the ionization of the most
important elements in self-consistent numerical simulations.
  Our newly developed 2D stellar atmosphere code, ASTAROTH, was used for the
numerical simulations. The code self-consistently solves for the continuum
radiation, non-LTE level populations, and electron temperature in axi-symmetric
stellar envelopes. Observed profiles were calculated by an auxiliary program
developed separately from ASTAROTH.
  In all but one of our models, H remained fully ionized. Due to ionizations
from excited states it is much more difficult to get a H neutral disk than
indicated by previous analytical calculations. Near the poles, the ionization
is high in all models, while helium recombined in the equatorial regions for
all but our lowest mass-loss rate. Although the model parameters were not
adjusted to provide fits to any particular star, the theoretical profiles show
some features seen in the profiles of R126. These include the partially
resolved double peaked profile of Halpha, and the weak emission associated with
the UV C IV resonance line.


title:
Balancing forward and feedback error correction for erasure channels
  with unreliable feedback

abstract:
  The traditional information theoretic approach to studying feedback is to
consider ideal instantaneous high-rate feedback of the channel outputs to the
encoder. This was acceptable in classical work because the results were
negative: Shannon pointed out that even perfect feedback often does not improve
capacity and in the context of symmetric DMCs, Dobrushin showed that it does
not improve the fixed block-coding error exponents in the interesting high rate
regime. However, it has recently been shown that perfect feedback does allow
great improvements in the asymptotic tradeoff between end-to-end delay and
probability of error, even for symmetric channels at high rate. Since gains are
claimed with ideal instantaneous feedback, it is natural to wonder whether
these improvements remain if the feedback is unreliable or otherwise limited.
  Here, packet-erasure channels are considered on both the forward and feedback
links. First, the feedback channel is considered as a given and a strategy is
given to balance forward and feedback error correction in the suitable
information-theoretic limit of long end-to-end delays. At high enough rates,
perfect-feedback performance is asymptotically attainable despite having only
unreliable feedback! Second, the results are interpreted in the zero- sum case
of "half-duplex" nodes where the allocation of bandwidth or time to the
feedback channel comes at the direct expense of the forward channel. It turns
out that even here, feedback is worthwhile since dramatically lower asymptotic
delays are possible by appropriately balancing forward and feedback error
correction.
  The results easily generalize to channels with strictly positive
zero-undeclared-error capacities.


title:
Magnetohydrodynamic Simulations of Disk Galaxy Formation: the
  Magnetization of The Cold and Warm Medium

abstract:
  Using magnetohydrodynamic (MHD) adaptive mesh refinement simulations, we
study the formation and early evolution of disk galaxies with a magnetized
interstellar medium. For a $10^{10}$ \msun halo with initial NFW dark matter
and gas profiles, we impose a uniform $10^{-9}$ G magnetic field and follow its
collapse, disk formation and evolution up to 1 Gyr. Comparing to a purely
hydrodynamic simulation with the same initial condition, we find that a
protogalactic field of this strength does not significantly influence the
global disk properties. At the same time, the initial magnetic fields are
quickly amplified by the differentially rotating turbulent disk. After the
initial rapid amplification lasting $\sim500$ Myr, subsequent field
amplification appears self-regulated. As a result, highly magnetized material
begin to form above and below the disk. Interestingly, the field strengths in
the self-regulated regime agrees well with the observed fields in the Milky Way
galaxy both in the warm and the cold HI phase and do not change appreciably
with time. Most of the cold phase shows a dispersion of order ten in the
magnetic field strength. The global azimuthal magnetic fields reverse at
different radii and the amplitude declines as a function of radius of the disk.
By comparing the estimated star formation rate (SFR) in hydrodynamic and MHD
simulations, we find that after the magnetic field strength saturates, magnetic
forces provide further support in the cold gas and lead to a decline of the
SFR.


title:
The price of ignorance: The impact of side-information on delay for
  lossless source-coding

abstract:
  Inspired by the context of compressing encrypted sources, this paper
considers the general tradeoff between rate, end-to-end delay, and probability
of error for lossless source coding with side-information. The notion of
end-to-end delay is made precise by considering a sequential setting in which
source symbols are revealed in real time and need to be reconstructed at the
decoder within a certain fixed latency requirement. Upper bounds are derived on
the reliability functions with delay when side-information is known only to the
decoder as well as when it is also known at the encoder.
  When the encoder is not ignorant of the side-information (including the
trivial case when there is no side-information), it is possible to have
substantially better tradeoffs between delay and probability of error at all
rates. This shows that there is a fundamental price of ignorance in terms of
end-to-end delay when the encoder is not aware of the side information. This
effect is not visible if only fixed-block-length codes are considered. In this
way, side-information in source-coding plays a role analogous to that of
feedback in channel coding.
  While the theorems in this paper are asymptotic in terms of long delays and
low probabilities of error, an example is used to show that the qualitative
effects described here are significant even at short and moderate delays.


title:
Discovery of Extended X-Ray emission from the unidentified TeV source
  HESS J1614-518 using the Suzaku Satellite

abstract:
  We report the Suzaku results of HESS J1614-518, which is the brightest
extended TeV gamma-ray source discovered in the Galactic plane survey conducted
using the H.E.S.S. telescope. We discovered three X-ray objects in the field of
view of the X-ray Imaging Spectrometer (XIS), which were designated as Suzaku
J1614-5141 (src A), Suzaku J1614-5152 (src B), and Suzaku J1614-5148 (src C).
Src A is an extended source located at the peak position of HESS J1614-518, and
therefore it is a plausible counterpart to HESS J1614-518. The X-ray flux in
the 2-10 keV band is 5e-13 erg/s/cm^2, which is an order of magnitude smaller
than the TeV flux. The photon index is 1.7, which is smaller than the canonical
value of synchrotron emissions from high-energy electrons found in some
supernova remnants. These findings present a challenge to models in which the
origin of the TeV emission is the inverse Compton scattering of the cosmic
microwave background by accelerated electrons that emit X-rays via synchrotron
emission. Src B is located at a relatively dim region in the TeV band image;
however, its hydrogen column density is the same as that of src A. Therefore,
src B may also be physically related to HESS J1614-518. Src C is a foreground
late-type B star. We also discovered a soft extended X-ray emission near HESS
J1614-518.


title:
Boundary layers and the vanishing viscosity limit for incompressible 2D
  flow

abstract:
  This manuscript is a survey on results related to boundary layers and the
vanishing viscosity limit for incompressible flow. It is the lecture notes for
a 10 hour minicourse given at the Morningside Center, Academia Sinica, Beijing,
PRC from 11/28 to 12/07, 2007. The main topics covered are: a derivation of
Prandtl's boundary layer equation; an outline of the rigorous theory of
Prandtl's equation, without proofs; Kato's criterion for the vanishing
viscosity limit; the vanishing viscosity limit with Navier friction condition;
rigorous boundary layer theory for the Navier friction condition and boundary
layers for flows in a rotating cylinder.


title: Gauge fixing and BRST formalism in non-Abelian gauge theories

abstract:
  In this Thesis we present a comprehensive study of perturbative and
non-perturbative non-Abelian gauge theories in the light of gauge-fixing
procedures, focusing our attention on the BRST formalism in Yang-Mills theory.
We propose first a model to re-write the Faddeev-Popov quantisation method in
terms of group-theoretical techniques and then we give a possible way to solve
the no-go theorem of Neuberger for lattice Yang-Mills theory with double BRST
symmetry. In the final part we present a study of the Batalin-Vilkovisky
quantisation method for non-linear gauges in non-Abelian gauge theories.


title:
Suzaku Spectroscopy of an X-Ray Reflection Nebula and a New Supernova
  Remnant Candidate in the Sgr B1 Region

abstract:
  We made a 100 ks observation of the Sagittarius (Sgr) B1 region at (l, b) =
(0.5, -0.1) near to the Galactic center (GC) with the Suzaku/XIS. Emission
lines of S XV, Fe I, Fe XXV, and Fe XXVI were clearly detected in the spectrum.
We found that the Fe XXV and Fe XXVI line emissions smoothly distribute over
the Sgr B1 and B2 regions connecting from the GC. This result suggests that the
GC hot plasma extends at least up to the Sgr B region with a constant
temperature. There are two diffuse X-ray sources in the observed region. One of
the two (G0.42-0.04) is newly discovered, and exhibits a strong S XV Ka
emission line, suggesting a candidate for a supernova remnant located in the GC
region. The other one (M0.51-0.10), having a prominent Fe I Ka emission line
and a strongly absorbed continuum, is likely to be an X-ray reflection nebula.
There is no near source bright enough to irradiate M0.51-0.10. However, the Fe
I Ka emission can be explained if Sgr A* was ~ 10^6 times brighter 300 years
ago, the light travel time for 100 pc to M0.51-0.10, than it is at present.


title: Friedel oscillations of screening in nanotubes

abstract:
  In 3D and 2D electronic systems the singular contribution to the static
permittivity $\epsilon$ (Kohn singularity) is a small correction to the regular
part of $\epsilon$ but it results in the leading term in asymptotic behavior of
the screened potential (Friedel oscillations). In the present letter we show
that for nanotubes quite different results are valid: $\epsilon$ becomes
infinitely large at the singular point and the Friedel oscillations do not play
the dominant role in the screening at the large distances. Moreover, the zero
and highest cylindrical harmonics of the effective potential are screened by
quite different mechanisms.


title: Quasi-particle propagation in quantum Hall systems

abstract:
  We study various geometrical aspects of the propagation of particles obeying
fractional statistics in the physical setting of the quantum Hall system. We
find a discrete set of zeros for the two-particle kernel in the lowest Landau
level; these arise from a combination of a two-particle Aharonov-Bohm effect
and the exchange phase related to fractional statistics. The kernel also shows
short distance exclusion statistics, for instance, in a power law behavior as a
function of initial and final positions of the particles. We employ the
one-particle kernel to compute impurity-mediated tunneling amplitudes between
different edges of a finite-sized quantum Hall system and and find that they
vanishes for certain strengths and locations of the impurity scattering
potentials. We show that even in the absence of scattering, the correlation
functions between different edges exhibits unusual features for a narrow enough
Hall bar.


title:
Loss of superfluidity in the Bose-Einstein condensate in an optical
  lattice with cubic and quintic nonlinearity

abstract:
  In a one-dimensional shallow optical lattice, in the presence of both cubic
and quintic nonlinearity, a superfluid density wave is identified in a
Bose-Einstein condensate. Interestingly, it ceases to exist when only one of
these interactions is operative. We predict the loss of superfluidity through a
classical dynamical phase transition, where modulational instability leads to
the loss of phase coherence. In a certain parameter domain, the competition
between lattice potential and the interactions is shown to give rise to a
stripe phase, where atoms are confined in finite domains. In a pure two-body
case, apart from the known superfluid and insulating phases, a density wave
insulating phase is found to exist, possessing two frequency modulations
commensurate with the lattice potential.


title: On the "degrees of freedom" of the lasso

abstract:
  We study the effective degrees of freedom of the lasso in the framework of
Stein's unbiased risk estimation (SURE). We show that the number of nonzero
coefficients is an unbiased estimate for the degrees of freedom of the lasso--a
conclusion that requires no special assumption on the predictors. In addition,
the unbiased estimator is shown to be asymptotically consistent. With these
results on hand, various model selection criteria--$C_p$, AIC and BIC--are
available, which, along with the LARS algorithm, provide a principled and
efficient approach to obtaining the optimal lasso fit with the computational
effort of a single ordinary least-squares fit.


title:
Critical line in undirected Kauffman boolean networks - the role of
  percolation

abstract:
  We show that to correctly describe the position of the critical line in the
Kauffman random boolean networks one must take into account percolation
phenomena underlying the process of damage spreading. For this reason, since
the issue of percolation transition is much simpler in random undirected
networks, than in the directed ones, we study the Kauffman model in undirected
networks. We derive the mean field formula for the critical line in the giant
component of these networks, and show that the critical line characterizing the
whole network results from the fact that the ordered behavior of small clusters
shields the chaotic behavior of the giant component. We also show a possible
attitude towards the analytical description of the shielding effect. The
theoretical derivations given in this paper quite tally with numerical
simulations done for classical random graphs.


title:
Understanding the physics of oligonucleotide microarrays: the Affymetrix
  spike-in data reanalysed

abstract:
  The Affymetrix U95 and U133 Latin Square spike-in datasets are reanalysed,
together with a dataset from a version of the U95 spike-in experiment without a
complex non-specific background. The approach uses a physico-chemical model
which includes the effects the specific and non-specific hybridisation and
probe folding at the microarray surface, target folding and hybridisation in
the bulk RNA target solution, and duplex dissociation during the
post-hybridisatoin washing phase. The model predicts a three parameter
hyperbolic response function that fits well with fluorescence intensity data
from all three datasets. The importance of the various hybridisation and
washing effects in determining each of the three parameters is examined, and
some guidance is given as to how a practical algorithm for determining specific
target concentrations might be developed.


title:
Very weak lensing in the CFHTLS Wide: Cosmology from cosmic shear in the
  linear regime

abstract:
  We present an exploration of weak lensing by large-scale structure in the
linear regime, using the third-year (T0003) CFHTLS Wide data release. Our
results place tight constraints on the scaling of the amplitude of the matter
power spectrum sigma_8 with the matter density Omega_m. Spanning 57 square
degrees to i'_AB = 24.5 over three independent fields, the unprecedented
contiguous area of this survey permits high signal-to-noise measurements of
two-point shear statistics from 1 arcmin to 4 degrees. Understanding systematic
errors in our analysis is vital in interpreting the results. We therefore
demonstrate the percent-level accuracy of our method using STEP simulations, an
E/B-mode decomposition of the data, and the star-galaxy cross correlation
function. We also present a thorough analysis of the galaxy redshift
distribution using redshift data from the CFHTLS T0003 Deep fields that probe
the same spatial regions as the Wide fields. We find sigma_8(Omega_m/0.25)^0.64
= 0.785+-0.043 using the aperture-mass statistic for the full range of angular
scales for an assumed flat cosmology, in excellent agreement with WMAP3
constraints. The largest physical scale probed by our analysis is 85 Mpc,
assuming a mean redshift of lenses of 0.5 and a LCDM cosmology. This allows for
the first time to constrain cosmology using only cosmic shear measurements in
the linear regime. Using only angular scales theta> 85 arcmin, we find
sigma_8(Omega_m/0.25)_lin^0.53 = 0.837+-0.084, which agree with the results
from our full analysis. Combining our results with data from WMAP3, we find
Omega_m=0.248+-0.019 and sigma_8 = 0.771+-0.029.


title:
Lightest scalar and tensor resonances in $\gamma\gamma\to\pi\pi$ after
  the Belle experiment

abstract:
  New high statistics Belle data on the $\gamma\gamma\to\pi^+\pi^-$ reaction
cross section measured in the range of pion-pair invariant masses $\sqrt{s}$
between 0.8 GeV and 1.5 GeV are analyzed to clarify the current situation
around the $\sigma(600)$, $f_0(980)$, and $f_2(1270)$ resonances in
$\gamma\gamma$ collisions. The present analysis shows that the direct coupling
constants of the $\sigma(600)$ and $f_0(980)$ resonances to $\gamma\gamma$ are
small, and the $\sigma(600)\to\gamma\gamma$ and $f_0(980)\to\gamma\gamma$
decays are four-quark transitions caused by the $\pi^+\pi^-$ and $K^+K^-$ loop
mechanisms, respectively. The chiral shielding of the $\sigma(600)$ resonance
takes place in the reactions $\gamma\gamma\to\pi\pi$ as well as in $\pi\pi$
scattering. Some results of a simultaneous description of the
$\gamma\gamma\to\pi^+\pi^-$ and $\gamma\gamma\to\pi^0\pi^0$ Belle data are also
presented. In particular, the following tentative estimate of the
$f_2(1270)\to\gamma\gamma$ decay width is obtained:
$\Gamma_{f_2\to\gamma\gamma}(m^2_{f_2})\approx 3.68$ keV.


title:
Towards Mirror Symmetry with Semi-Realistic Intersecting Brane
  Configurations

abstract:
  A T6 orbifold compactification is discussed from the somewhat unconventional
perspective as the large radius limit of a Landau-Ginzburg model. The features
of the model are in principle familiar, but the way they enter here is
different from the way they enter when using more commonly used methods. It is
hoped that the point of view presented here can supplement the understanding of
the features used in string compactifications, notably in terms of naturalness
and completeness. More precisely, the analyzed T6 / Z_4 x Z_4 features two
different kinds of O-planes, branes in the bulk as well as fractional branes,
continuous and discrete Wilson lines as well as an orientifold action which can
act in different ways on the Wilson lines. The D-branes are desribed by matrix
factorizations. This work is also intended to be a showcase for the potentials
of matrix factorizations which are for the first time geared to their full
level of sophistication in this paper. Throughout the analyis everything is
mapped from the B-model side of the LG-model to the A side by mirror symmetry.
The work could be extended straightforwardly yet tediously to perform mirror
symmetry on a general intersecting brane configuration and to compute Yukawa
couplings. The analysis presented here can also be applied to non-toroidal
backgrounds with an intersecting brane configuration on it, so I hope that it
will be a helpful basis for later applications of mirror symmetry to models
exhibiting real world properties.


title:
A random walk description of the heterogeneous glassy dynamics of
  attracting colloids

abstract:
  We study the heterogeneous dynamics of attractive colloidal particles close
to the gel transition using confocal microscopy experiments combined with a
theoretical statistical analysis. We focus on single particle dynamics and show
that the self part of the van Hove distribution function is not the Gaussian
expected for a Fickian process, but that it reflects instead the existence, at
any given time, of colloids with widely different mobilities. Our confocal
microscopy measurements can be described well by a simple analytical model
based on a conventional continuous time random walk picture, as already found
in several other glassy materials. In particular, the theory successfully
accounts for the presence of broad tails in the van Hove distributions that
exhibit exponential, rather than Gaussian, decay at large distance.


title: Abilities of multidimensional gravity

abstract:
  We show that a number of problems of modern cosmology may be addressed and
solved in the framework of multidimensional gravity with high-order curvature
invariants, without invoking other fields. As applications of this approach, we
mention primordial inflation and particle production after it; description of
the modern accelerated stage of the Universe with stable compact extra
dimensions; construction of asymmetric thick brane-world models.


title: Gaia: Organisation and challenges for the data processing

abstract:
  Gaia is an ambitious space astrometry mission of ESA with a main objective to
map the sky in astrometry and photometry down to a magnitude 20 by the end of
the next decade. While the mission is built and operated by ESA and an
industrial consortium, the data processing is entrusted to a consortium formed
by the scientific community, which was formed in 2006 and formally selected by
ESA one year later. The satellite will downlink around 100 TB of raw telemetry
data over a mission duration of 5 years from which a very complex iterative
processing will lead to the final science output: astrometry with a final
accuracy of a few tens of microarcseconds, epoch photometry in wide and narrow
bands, radial velocity and spectra for the stars brighter than 17 mag. We
discuss the general principles and main difficulties of this very large data
processing and present the organisation of the European Consortium responsible
for its design and implementation.


title: On closure operators and reflections in Goursat categories

abstract:
  By defining a closure operator on effective equivalence relations in a
regular category $C$, it is possible to establish a bijective correspondence
between these closure operators and the regular epireflective subcategories $L$
of $C$. When $C$ is an exact Goursat category this correspondence restricts to
a bijection between the Birkhoff closure operators on effective equivalence
relations and the Birkhoff subcategories of $C$. In this case it is possible to
provide an explicit description of the closure, and to characterise the
congruence distributive Goursat categories.


title: Statistical physics in deformed spaces with minimal length

abstract:
  We considered the thermodynamics in spaces with deformed commutation relation
leading to existence of the minimal length. We developed a classical method of
the partition function evaluation. We calculated the partition function and
heat capacity for ideal gas and harmonic oscillators using this method. The
obtained results are in good agreement with the exact quantum ones. We also
showed that the minimal length introduction reduces degrees of freedom of an
arbitrary system in the high temperature limit significantly.


title:
On surrogate dimension reduction for measurement error regression: An
  invariance law

abstract:
  We consider a general nonlinear regression problem where the predictors
contain measurement error. It has been recently discovered that several
well-known dimension reduction methods, such as OLS, SIR and pHd, can be
performed on the surrogate regression problem to produce consistent estimates
for the original regression problem involving the unobserved true predictor. In
this paper we establish a general invariance law between the surrogate and the
original dimension reduction spaces, which implies that, at least at the
population level, the two dimension reduction problems are in fact equivalent.
Consequently we can apply all existing dimension reduction methods to
measurement error regression problems. The equivalence holds exactly for
multivariate normal predictors, and approximately for arbitrary predictors. We
also characterize the rate of convergence for the surrogate dimension reduction
estimators. Finally, we apply several dimension reduction methods to real and
simulated data sets involving measurement error to compare their performances.


title:
Anomalous transport in biased ac-driven Josephson junctions: Negative
  conductances

abstract:
  We investigate classical anomalous electrical transport in a driven,
resistively and capacitively shunted Josephson junction device. Novel transport
phenomena are identified in chaotic regimes when the junction is subjected to
both, a time periodic (ac) and a constant, biasing (dc) current. The dependence
of the voltage across the junction on the dc-current exhibits a rich diversity
of anomalous transport characteristics: In particular, depending on the chosen
parameter regime we can identify so termed absolute negative conductance around
zero dc-bias, the occurrence of negative differential conductance and, after
crossing a zero conductance, the emergence of a negative nonlinear conductance
in the non-equilibrium response regime remote from zero dc-bias.


title:
Optimal third root asymptotic bounds in the statistical estimation of
  thresholds

abstract:
  This paper is concerned with estimating the intersection point of two
densities, given a sample of both of the densities. This problem arises in
classification theory. The main results provide lower bounds for the
probability of the estimation errors to be large on a scale determined by the
inverse cube root of the sample size. As corollaries, we obtain probabilistic
bounds for the prediction error in a classification problem. The key to the
proof is an entropy estimate. The lower bounds are based on bounds for general
estimators, which are applicable in other contexts as well. Furthermore, we
introduce a class of optimal estimators whose errors asymptotically meet the
border permitted by the lower bounds.


title: A mean-field model for the electron glass dynamics

abstract:
  We study a microscopic mean-field model for the dynamics of the electron
glass, near a local equilibrium state. Phonon-induced tunneling processes are
responsible for generating transitions between localized electronic sites,
which eventually lead to the thermalization of the system. We find that the
decay of an excited state to a locally stable state is far from being
exponential in time, and does not have a characteristic time scale. Working in
a mean-field approximation, we write rate equations for the average occupation
numbers, and describe the return to the locally stable state using the
eigenvalues of a rate matrix, A, describing the linearized time-evolution of
the occupation numbers. Analyzing the probability distribution of the
eigenvalues of A we find that, under certain physically reasonable assumptions,
it takes the form $P(\lambda) \sim \frac{1}{|\lambda|}$, leading naturally to a
logarithmic decay in time. While our derivation of the matrix A is specific for
the chosen model, we expect that other glassy systems, with different
microscopic characteristics, will be described by random rate matrices
belonging to the same universality class of A. Namely, the rate matrix has
elements with a very broad distribution, i.e., exponentials of a variable with
nearly uniform distribution.


title: Quantum state decorrelation

abstract:
  We address the general problem of removing correlations from quantum states
while preserving local quantum information as much as possible. We provide a
complete solution in the case of two qubits, by evaluating the minimum amount
of noise that is necessary to decorrelate covariant sets of bipartite states.
We show that two harmonic oscillators in arbitrary Gaussian state can be
decorrelated by a Gaussian covariant map. Finally, for finite-dimensional
Hilbert spaces, we prove that states obtained from most cloning channels (e.g.,
universal and phase-covariant cloning) can be decorrelated only at the expense
of a complete erasure of information about the copied state. More generally, in
finite dimension, cloning without correlations is impossible for continuous
sets of states. On the contrary, for continuos variables cloning, a slight
modification of the customary set-up for cloning coherent states allows one to
obtain clones without correlations.


title: Reactor Neutrino Experiments

abstract:
  Precisely measuring $\theta_{13}$ is one of the highest priority in neutrino
oscillation study. Reactor experiments can cleanly determine $\theta_{13}$.
Past reactor neutrino experiments are reviewed and status of next precision
$\theta_{13}$ experiments are presented. Daya Bay is designed to measure
$\sin^22\theta_{13}$ to better than 0.01 and Double Chooz and RENO are designed
to measure it to 0.02-0.03. All are heading to full operation in 2010. Recent
improvements in neutrino moment measurement are also briefed.


title:
Variance estimation in nonparametric regression via the difference
  sequence method

abstract:
  Consider a Gaussian nonparametric regression problem having both an unknown
mean function and unknown variance function. This article presents a class of
difference-based kernel estimators for the variance function. Optimal
convergence rates that are uniform over broad functional classes and bandwidths
are fully characterized, and asymptotic normality is also established. We also
show that for suitable asymptotic formulations our estimators achieve the
minimax rate.


title:
Doppler imaging an X-ray flare on the ultrafast rotator BO Mic - A
  contemporaneous multiwavelength study using XMM-Newton and VLT

abstract:
  We present an analysis of contemporaneous photospheric, chromospheric and
coronal structures on the highly active K-dwarf star BO Mic (Speedy Mic). We
localize a moderate flare in the stellar atmosphere and study its energetics,
size and thermal behaviour. The analysis is based on strictly simultaneous
X-ray, UV- and optical observations carried out by XMM-Newton and the VLT. We
use Doppler imaging and related methods for the localization of features. Based
on X-ray spectroscopy we study the the coronal plasma in and outside the flare.
The flare emits in X-rays and UV, but is not detected in white light; it is
located at intermediate latitude between an extended spot group and the weakly
spotted pole. We estimate its height below 0.4 stellar radii making it clearly
distinct in longitude and height from the prominences found about two stellar
radii above the surface. While BO Mic's photospheric brightness is modulated
due to extended starspots, neither the chromospheric nor the X-ray emission
show a pronounced rotational modulation.


title:
Modeling the pressure Hessian and viscous Laplacian in Turbulence:
  comparisons with DNS and implications on velocity gradient dynamics

abstract:
  Modeling the velocity gradient tensor A along Lagrangian trajectories in
turbulent flow requires closures for the pressure Hessian and viscous Laplacian
of A. Based on an Eulerian-Lagrangian change of variables and the so-called
Recent Fluid Deformation closure, such models were proposed recently. The
resulting stochastic model was shown to reproduce many geometric and anomalous
scaling properties of turbulence. In this work, direct comparisons between
model predictions and Direct Numerical Simulation (DNS) data are presented.
First, statistical properties of A are described using conditional averages of
strain skewness, enstrophy production, energy transfer and vorticity
alignments, conditioned upon invariants of A. These conditionally averaged
quantities are found to be described accurately by the stochastic model. More
detailed comparisons that focus directly on the terms being modeled in the
closures are also presented. Specifically, conditional statistics associated
with the pressure Hessian and the viscous Laplacian are measured from the model
and are compared with DNS. Good agreement is found in strain-dominated regions.
However, some features of the pressure Hessian linked to rotation dominated
regions are not reproduced accurately by the model. Geometric properties such
as vorticity alignment with respect to principal axes of the pressure Hessian
are mostly predicted well. In particular, the model predicts that an
eigenvector of the rate-of-strain will be also an eigenvector of the pressure
Hessian, in accord to basic properties of the Euler equations. The analysis
identifies under what conditions the Eulerian-Lagrangian change of variables
with the Recent Fluid Deformation closure works well, and in which flow regimes
it requires further improvements.


title:
Iterative estimating equations: Linear convergence and asymptotic
  properties

abstract:
  We propose an iterative estimating equations procedure for analysis of
longitudinal data. We show that, under very mild conditions, the probability
that the procedure converges at an exponential rate tends to one as the sample
size increases to infinity. Furthermore, we show that the limiting estimator is
consistent and asymptotically efficient, as expected. The method applies to
semiparametric regression models with unspecified covariances among the
observations. In the special case of linear models, the procedure reduces to
iterative reweighted least squares. Finite sample performance of the procedure
is studied by simulations, and compared with other methods. A numerical example
from a medical study is considered to illustrate the application of the method.


title: Orthogonal black di-ring solution

abstract:
  We construct a five dimensional exact solution of the orthogonal black
di-ring which has two black rings whose $S^1$-rotating planes are orthogonal.
This solution has four free parameters which represent radii of and speeds of
$S^1$-rotation of the black rings. We use the inverse scattering method. This
method needs the seed metric. We also present a systematic method how to
construct a seed metric. Using this method, we can probably construct other
solutions having many black rings on the two orthogonal planes with or without
a black hole at the center.


title: Neutrino Sector with Majorana Mass Terms and Friedberg-Lee Symmetry

abstract:
  We examine a recently proposed symmetry/condition by Friedberg and Lee in the
framework where three right-handed neutrinos are added to the spectrum of the
three-family Minimal Standard Model. It is found that the right-handed
neutrinos are very special, with respect to this symmetry. In the symmetry
limit the neutrinos are massless and that may be a hint about why they are
light. Imposed as a condition and not as a full symmetry, we find that one of
the three right-handed neutrinos simply decouples (has only gravitational
interactions) and that there is a massless interacting neutrino. The possible
relation of the model to the see-saw mechanism is briefly discussed.


title: On optimality of Bayesian testimation in the normal means problem

abstract:
  We consider a problem of recovering a high-dimensional vector $\mu$ observed
in white noise, where the unknown vector $\mu$ is assumed to be sparse. The
objective of the paper is to develop a Bayesian formalism which gives rise to a
family of $l_0$-type penalties. The penalties are associated with various
choices of the prior distributions $\pi_n(\cdot)$ on the number of nonzero
entries of $\mu$ and, hence, are easy to interpret. The resulting Bayesian
estimators lead to a general thresholding rule which accommodates many of the
known thresholding and model selection procedures as particular cases
corresponding to specific choices of $\pi_n(\cdot)$. Furthermore, they achieve
optimality in a rather general setting under very mild conditions on the prior.
We also specify the class of priors $\pi_n(\cdot)$ for which the resulting
estimator is adaptively optimal (in the minimax sense) for a wide range of
sparse sequences and consider several examples of such priors.


title: Two-band ferromagnetic Kondo-lattice model for local-moment half-metals

abstract:
  We introduce a two-band Kondo-lattice model to describe ferromagnetic
half-metals with local magnetic moments. In a model study, the electronic and
magnetic properties are presented by temperature dependent magnetization
curves, band-structures, spin polarizations and plasma frequencies. These are
obtained from numerically evaluated equations, based on the single-electron
Green functions. We show that the mutual influence between the itinerant
electrons and the local magnetic moments is responsible for several phase
transitions of the half-metals, namely first and second order magnetic phase
transitions, as well as half-metal to semiconductor and half-metal to semimetal
transitions.


title: Rising Total Hadron-Hadron Cross Sections

abstract:
  A historical summary is made on the measurements concerning the rising total
hadron-hadron cross sections at high energies. The first part of this paper
concerns the total cross section measurements performed at the Brookhaven,
Serpukhov and Fermilab fixed target accelerators; then the measurements at the
CERN Intersecting Storage Rings (ISR), and at the CERN and at the Tevatron
Fermilab proton-antiproton colliders; finally the cosmic ray measurements at
even higher energies. A short discussion on Conclusions and Perspectives
follows.


title:
A first-principles study of the electronic structure and stability of
  Be(BH4)2

abstract:
  Alanates and boranates are studied intensively because of their potential use
as hydrogen storage materials. In this paper we present a first-principles
study of the electronic structure and the energetics of beryllium boranate,
Be(BH4)2. From total energy calculations we show that - in contrast to the
other boranates and alanates - hydrogen desorption directly to the elements is
likely, and is at least competitive with desorption to the elemental hydride
(BeH2). The formation enthalpy of Be(BH4)2 is only -0.12 eV/H2 (at T=0K). This
low value can be rationalized by the participation of all atoms in the covalent
bonding, in contrast to the ionic bonding observed in other boranates. From
calculations of thermodynamic properties at finite temperature we estimate a
decomposition temperature of 162 K at a pressure of 1 bar.


title:
Theory of Operation of Direct String Magnetic Gradiometer with
  Proportional and Integral Feedback

abstract:
  A quantitative theory of operation of a novel device, namely Direct String
Magnetic Gradiometer (DSMG), is presented. The paper provides a detailed
analysis of DSMG basic functions and measured quantities, represented in terms
of physical parameters that are known either a priori or can be experimentally
determined. It leaves a reasonable degree of freedom to further investigate
some of the finer detail of this new instrument based on experimental results
coming both from the laboratory environment and from field trials. The analysis
also allows us to quantitatively evaluate the error budget for an optimised
DSMG.


title: Physics and Performance Evaluation Group

abstract:
  We summarize the objectives and results of the ``international scoping study
of a future neutrino factory and superbeam facility'' (ISS) physics working
group. Furthermore, we discuss how the ISS study should develop into a neutrino
factory design study (IDS-NF) from the point of view of physics and performance
evaluation.


title:
A Lohner-type algorithm for control systems and ordinary differential
  inclusions

abstract:
  We describe a Lohner-type algorithm for the computation of rigorous upper
bounds for reachable set for control systems, solutions of ordinary
differential inclusions and perturbations of ODEs.


title: Implementation of an Optimised Cassegrain System for Radio Telescopes

abstract:
  We present the antenna design for a radio interferometer, the Arcminute
Microkelvin Imager, together with its beam pattern measurement. Our aim was to
develop a low-cost system with high aperture efficiency and low ground-spill
across the frequency range 12-18GHz. We use a modified cassegrain system
consisting of a commercially-available paraboloidal primary mirror with a
diameter of 3.7m, and a shaped secondary mirror. The secondary mirror is
oversized with respect to a ray-optics design and has a surface that is bent
towards the primary near its outer edge using a square term for the shaping.
The antennas are simple to manufacture and therefore their cost is low. The
design increased the antenna gain by approximately 10 per cent compared to a
normal Cassegrain system while still maintaining low contamination from
ground-spill and using a simple design for the horn.


title: Empirical regularities of order placement in the Chinese stock market

abstract:
  Using ultra-high-frequency data extracted from the order flows of 23 stocks
traded on the Shenzhen Stock Exchange, we study the empirical regularities of
order placement in the opening call auction, cool period and continuous
auction. The distributions of relative logarithmic prices against reference
prices in the three time periods are qualitatively the same with quantitative
discrepancies. The order placement behavior is asymmetric between buyers and
sellers and between the inside-the-book orders and outside-the-book orders. In
addition, the conditional distributions of relative prices in the continuous
auction are independent of the bid-ask spread and volatility. These findings
are crucial to build an empirical behavioral microscopic model based on order
flows for Chinese stocks.


title: The radial structure of protostellar accretion disks: influence of jets

abstract:
  The radial structure of accretion disks is a fundamental issue regarding star
and planet formation. Many theoretical studies, focussing on different aspects
such as e.g. disk emissivity or ionization, have been conducted in the context
of the Standard Accretion Disk (SAD) model, where no jet is present. We wish to
calculate the structure of YSO accretion disks in an approach that takes into
account the presence of the protostellar jets. The radial structure of these
Jet Emitting Disks (JED) should then be compared to that of standard accretion
disks. The analytical treatment used in this work is very similar to that of
standard accretion disks but is using the parameter space of Magnetised
Accretion-Ejection Structures that include the jet torque on the underlying
disk. In this framework, the analytical expressions of key quantities, such as
mid-plane temperatures, surface densities or disk aspect ratio are derived. It
is found that JEDs present a structure very different from the SADs and that
can be observationally tested. The implications on planet formation in the
inner regions of accretion disks are briefly discussed. We also supply sets of
analytical formulae, valid in different opacity regimes, for the disk
quantities. These expressions can be readily used for any work where the disk
structure is needed as an input for the model.


title: Contraction semigroups on metric graphs

abstract:
  The main objective of the present work is to study contraction semigroups
generated by Laplace operators on metric graphs, which are not necessarily
self-adjoint. We prove criteria for such semigroups to be continuity and
positivity preserving. Also we provide a characterization of generators of
Feller semigroups on metric graphs.


title: Differentiability of the volume of a region enclosed by level sets

abstract:
  The level of a function f on an n-dimensional space encloses a region. The
volume of a region between two such levels depends on both levels. Fixing one
of them the volume becomes a function of the remaining level. We show that if
the function f is smooth, the volume function is again smooth for regular
values of f. For critical values of f the volume function is only finitely
differentiable. The initial motivation for this study comes from Radiotherapy,
where such volume functions are used in an optimization process. Thus their
differentiability properties become important.


title:
Finite de Finetti theorem for conditional probability distributions
  describing physical theories

abstract:
  We work in a general framework where the state of a physical system is
defined by its behaviour under measurement and the global state is constrained
by no-signalling conditions. We show that the marginals of symmetric states in
such theories can be approximated by convex combinations of independent and
identical conditional probability distributions, generalizing the classical
finite de Finetti theorem of Diaconis and Freedman. Our results apply to
correlations obtained from quantum states even when there is no bound on the
local dimension, so that known quantum de Finetti theorems cannot be used.


title: Some properties of finite meadows

abstract:
  The aim of this note is to describe the structure of finite meadows. We will
show that the class of finite meadows is the closure of the class of finite
fields under finite products. As a corollary, we obtain a unique representation
of minimal meadows in terms of prime fields.


title: Some thoughts about matrix coordinate transformations

abstract:
  Matrix coordinate transformations are defined as substitution operators
without requiring an ordering prescription or an inclusion function from the
Abelian coordinate transformations. We construct transforming objects mimicking
most of the properties of tensors. We point out some problems with the matrix
generalization of contravariant vectors. We suggest to use the substitution
operators to search for an inclusion function.


title: Modeling slow deformation of polygonal particles using DEM

abstract:
  We introduce two improvements in the numerical scheme to simulate collision
and slow shearing of irregular particles. First, we propose an alternative
approach based on simple relations to compute the frictional contact forces.
The approach improves efficiency and accuracy of the Discrete Element Method
(DEM) when modeling the dynamics of the granular packing. We determine the
proper upper limit for the integration step in the standard numerical scheme
using a wide range of material parameters. To this end, we study the kinetic
energy decay in a stress controlled test between two particles. Second, we show
that the usual way of defining the contact plane between two polygonal
particles is, in general, not unique which leads to discontinuities in the
direction of the contact plane while particles move. To solve this drawback, we
introduce an accurate definition for the contact plane based on the shape of
the overlap area between touching particles, which evolves continuously in
time.


title: Choice Number and Energy of Graphs

abstract:
  The energy of a graph G, denoted by E(G), is defined as the sum of the
absolute values of all eigenvalues of G. It is proved that E(G)>=
2(n-\chi(\bar{G}))>= 2(ch(G)-1) for every graph G of order n, and that E(G)>=
2ch(G) for all graphs G except for those in a few specified families, where
\bar{G}, \chi(G), and ch(G) are the complement, the chromatic number, and the
choice number of G, respectively.


title: Going Beyond Bell's Theorem

abstract:
  Bell's Theorem proved that one cannot in general reproduce the results of
quantum theory with a classical, deterministic local model. However, Einstein
originally considered the case where one could define an 'element of reality',
namely for the much simpler case where one could predict with certainty a
definite outcome for an experiment. For this simple case, Bell's Theorem says
nothing. But by using a slightly more complicated model than Bell, one can show
that even in this simple case where one can make definite predictions, one
still cannot generally introduce deterministic, local models to explain the
results.


title: Transgression and Clifford algebras

abstract:
  Let $W$ be a differential (not necessarily commutative) algebra which carries
a free action of a polynomial algebra $SP$ with homogeneous generators $p_1,
>..., p_r$. We show that for $W$ acyclic, the cohomology of the quotient
$H(W/<p_1, ..., p_r>)$ is isomorphic to a Clifford algebra $\text{Cl}(P,B)$,
where the (possibly degenerate) bilinear form $B$ depends on $W$. This
observation is an analogue of an old result of Borel in a non-commutative
context. As an application, we study the case of $W$ given by the quantized
Weil algebra $\qWg = \Ug \otimes \Clg$ for $\Lieg$ a reductive Lie algebra. The
resulting cohomology of the canonical Weil differential gives a Clifford
algebra, but the bilinear form vanishes on the space of primitive invariants of
the semi-simple part. As an application, we consider the deformed Weil
differential (following Freed, Hopkins and Teleman).