title: Cartan Invariants of Symmetric Groups and Iwahori-Hecke Algebras

abstract:
  K\"{u}lshammer, Olsson and Robinson conjectured that a certain set of numbers
determined the invariant factors of the $\ell$-Cartan matrix for $S_n$
(equivalently, the invariant factors of the Cartan matrix for the Iwahori-Hecke
algebra $\mathcal{H}_n(q)$, where $q$ is a primitive $\ell$th root of unity).
We call these invariant factors Cartan invariants.
  In a previous paper, the second author calculated these Cartan invariants
when $\ell=p^r$, $p$ prime, and $r\leq p$ and went on to conjecture that the
formulae should hold for all $r$. Another result was obtained, which is
surprising and counterintuitive from a block theoretic point of view. Namely,
given the prime decomposition $\ell=p_1^{r_1}... p_k^{r_k}$, the Cartan matrix
of an $\ell$-block of $S_n$ is a product of Cartan matrices associated to
$p_i^{r_i}$-blocks of $S_n$. In particular, the invariant factors of the Cartan
matrix associated to an $\ell$-block of $S_n$ can be recovered from the Cartan
matrices associated to the $p_i^{r_i}$-blocks.
  In this paper, we formulate an explicit combinatorial determination of the
Cartan invariants of $S_n$--not only for the full Cartan matrix, \emph{but for
an individual block}. We collect evidence for this conjecture, by showing that
the formulae predict the correct determinant of the $\ell$-Cartan matrix. We
then go on to show that Hill's conjecture implies the conjecture of KOR.


title: Trumpler 20 - an old and rich open cluster

abstract:
  We show that the open cluster Trumpler 20, contrary to the earlier findings,
is actually an old Galactic open cluster. New CCD photometry and
high-resolution spectroscopy are used to derive the main parameters of this
cluster. At [Fe/H]=-0.11 for a single red giant star, the metallicity is
slightly subsolar. The best fit to the color-magnitude diagrams is achieved
using a 1.3 Gyr isochrone with convective overshoot. The cluster appears to
have a significant reddening at E(B-V)=0.46 (for B0 spectral type), although
for red giants this high reddening yields the color temperature exceeding the
spectroscopic T_eff by about 200 K. Trumpler 20 is a very rich open cluster,
containing at least 700 members brighter than M_V=+4. It may extend over the
field-of-view available in our study at 20'x20'.


title:
Ground state cooling of nanomechanical resonator via parametric linear
  coupling

abstract:
  We present a ground state cooling scheme for a nanomechanical resonator
linearly coupled with a LC oscillator. The linear coupling, when periodically
modulated at red detuning, up-converts the low-frequency nanomechanical mode to
the high-frequency LC oscillator mode and generates backaction force that can
cool the resonator to its ground state in the resolved-sideband regime. We also
study the effect of the quantum backaction noise on the cooling due to the
counter rotating term in the linear coupling. The scheme can be compared with
laser cooling for the atomic systems and can be realized in superconducting
circuits.


title: Nanoelectronic Devices: A Unified View

abstract:
  Nanoscale electronic devices are of great interest for all kinds of
applications like switching, energy conversion and sensing. The objective of
this chapter, however, is not to discuss specific devices or applications.
Rather it is to convey the conceptual framework that has emerged over the last
twenty years, which is important not only because of the practical insights it
provides into the design of nanoscale devices, but also because of the
conceptual insights it affords regarding the meaning of resistance and the
essence of all non-equilibrium phenomena in general. We present a unified
description applicable to a wide variety of devices from molecular conductors
to carbon nanotubes to silicon transistors covering different transport regimes
from the ballistic to the diffusive limit, based on what we call the
NEGF-Landauer approach.


title: Towards fast quantum key distribution with quantum frames

abstract:
  We propose and investigate a fibre-based quantum key distribution system,
which employs polarization qubits encoded into faint laser pulses. As a novel
feature, it allows sending of classical framing information via sequences of
strong laser pulses that precede the quantum data. This allows synchronization,
sender and receiver identification, and compensation of time-varying
birefringence in the communication channel. Furthermore, this method also
provides a platform to communicate implementation specific information such as
encoding and protocol in view of future optical quantum networks. All optical
components can be operated at Gbps rates, which is a first requirement for Mbps
secret key rates.


title: Blue spectral inflation

abstract:
  We reconsider the nonlinear second order Abel equation of Stewart and Lyth,
which follows from a nonlinear second order slow-roll approximation. We find a
new eigenvalue spectrum in the blue regime. Some of the discrete values of the
spectral index n_s have consistent fits to the cumulative COBE data as well as
to recent ground-base CMB experiments.


title: Generation and syzygies of the first secant variety

abstract:
  Under certain effective positivity conditions, we show that the secant
variety to a smooth variety satisfies $N_{3,p}$. For smooth curves, we provide
the best possible effective bound on the degree $d$ of the embedding, $d\geq
2g+3+p$.


title:
Effective Theory of Braid Excitations of Quantum Geometry in terms of
  Feynman Diagrams

abstract:
  We study interactions amongst topologically conserved excitations of quantum
theories of gravity, in particular the braid excitations of four-valent spin
networks. These have been shown previously to propagate and interact under
evolution rules of spin foam models. We show that the dynamics of these braid
excitations can be described by an effective theory based on Feynman diagrams.
In this language, braids which are actively interacting are analogous to
bosons, in that the topological conservation laws permit them to be singly
created and destroyed. Exchanges of these excitations give rise to interactions
between braids which are charged under the topological conservation rules.


title:
A variation of the clock paradox and a distinguishing feature of an
  inertial frame

abstract:
  The clock paradox is analyzed for the case when the onward and return trips
cover the same <<distance>> (as observed by the traveling twin) but at unequal
velocities. In this case the stationary twin observes the distances covered by
her sister during the onward and return trips to be different. The analysis is
presented using formulations of special relativity and the only requirement for
consistency is that all observations are made from any one chosen inertial
frame. The analysis suggests that a defining feature of an inertial frame
should be based on the continued maintenance of the distinctive synchronicity
of the clocks co-moving with it. Published in Journal of Physical and Natural
Sciences Volume 1, Issue 1, 2007
http://www.scientificjournals.org/journals2007/articles/1102.pdf


title: A term-rewriting system for computer quantum algebra

abstract:
  Existing computer algebra packages do not fully support quantum mechanics
calculations in Dirac's notation. I present the foundation for building such
support: a mathematical system for the symbolic manipulation of expressions
used in the invariant formalism of quantum mechanics. I first describe the
essential mathematical features of the Hilbert-space invariant formalism. This
is followed by a formal characterisation of all possible algebraic expressions
in this formalism. This characterisation is provided in the form of a set of
terms. Rewrite rules over this set of terms are then developed that correspond
to allowed manipulations of the algebraic expressions. This approach is
contrasted with current attempts to build invariant quantum mechanics
calculations into computer algebra systems.


title:
Magnetic Behavior of Single Crystalline Pr_{5}Ge_{3} and
  Tb_{5}Ge_{3}Compounds

abstract:
  The results of the magnetization studies on Pr_{5}Ge_{3}and Tb_{5}Ge_{3}
single crystals are reported. Single Crystals of Pr_{5}Ge_{3} and Tb_{5}Ge_{3}
compounds were successfully grown by Czochralski method. These compounds
crystallize in a Mn_{5}Si_{3} type hexagonal structure with space group
P6_{3}/mcm. Ferromagnetic correlations set in at around 36 K in Pr_{5}Ge_{3} in
the ab plane followed by an antiferromagnetic transition at 13 K. Along the
c-axis the magnetization shows a ferromagnetic transition around 13 K with an
overall ferrimagnetic behavior. At 2K, the magnetic isotherm of the compound
along [0001] direction is typical for a ferromagnet, while a field induced
ferromagnetic type response is observed along the [10\overline{\mathit{1}}0]
direction. Hexagonal ab plane or [10\overline{\mathit{1}}0] direction was found
to be the easy axis of magnetization. Tb_{5}Ge_{3} orders antiferromagneticaly
at 85 K with the hexagonal ab plane as easy axis of magnetization. The compound
shows a field induced ferromagnetic behavior in its magnetic isotherm at 2 K.


title:
Non-Meissner electrodynamics and knotted solitons in two-component
  superconductors

abstract:
  I consider electrodynamics and the problem of knotted solitons in
two-component superconductors. Possible existence of knotted solitons in
multicomponent superconductors was predicted several years ago. However their
basic properties and stability in these systems remains an outstandingly
difficult question both for analytical and numerical treatment. Here I propose
a new perturbative approach to treat self-consistently all the degrees of
freedom in the problem. I show that there exists a length scale for a Hopfion
texture where the electrodynamics of a two-component superconductor is
dominated by a self-induced Faddeev term, which is a stark contrast to the
Meissner electrodynamics of single-component systems. I also show that at
certain short length scales knotted solitons in two-component Ginzburg-Landau
model are not described by a Faddeev-Skyrme-type model and are unstable.
However these solitons can be stable at some intermediate length scales. I
argue that configurations with a high topological charge may be more stable in
this system than low-topological-charge configurations. In the second part of
the paper I discuss qualitatively different physics of the stability of knotted
solitons in a more general Ginzburg-Landau model and point out the physically
relevant terms which enhance or suppress stability of the knotted solitons.
With this argument it is demonstrated that the generalized Ginburg-Landau model
possesses stable knotted solitons.


title: On Global Effects Caused by Locally Noneffective Unitary Operations

abstract:
  Given a bipartite quantum state rho with subsystems A and B of arbitrary
dimensions, we study the entanglement detecting capabilities of locally
noneffective, or cyclic, unitary operations [L. B. Fu, Europhys. Lett., vol.
75, pp. 1-7, 2006]. Local cyclic unitaries have the special property that they
leave their target subsystem invariant. We investigate the distance between rho
and the global state after local application of such unitaries as a possible
indicator of entanglement. To this end, we derive and discuss closed formulae
for the maximal such distance achievable for three cases of interest:
(pseudo)pure quantum states, Werner states, and two-qubit states. What makes
this criterion interesting, as we show here, is that it surprisingly displays
behavior similar to recent anomalies observed for non-locality measures in
higher dimensions, as well as demonstrates an equivalence to the CHSH
inequality for certain classes of two-qubit states. Yet, despite these
similarities, the criterion is not itself a non-locality measure. We also
consider entanglement detection in bound entangled states.


title: Deep Mixing and Metallicity: Carbon Depletion in Globular Cluster Giants

abstract:
  We present the results of an observational study of the efficiency of deep
mixing in globular cluster red giants as a function of stellar metallicity. We
determine [C/Fe] abundances based on low-resolution spectra taken with the Kast
spectrograph on the 3m Shane telescope at Lick Observatory. Spectra centered on
the 4300 Angstrom CH absorption band were taken for 42 bright red giants in 11
Galactic globular clusters ranging in metallicity from M92 ([Fe/H]=-2.29) to
NGC 6712 ([Fe/H]=-1.01). Carbon abundances were derived by comparing values of
the CH bandstrength index S2(CH) measured from the data with values measured
from a large grid of SSG synthetic spectra. Present-day abundances are combined
with theoretical calculations of the time since the onset of mixing, which is
also a function of stellar metallicity, to calculate the carbon depletion rate
across our metallicity range. We find that the carbon depletion rate is twice
as high at a metallicity of [Fe/H]=-2.3 than at [Fe/H]=-1.3, which is a result
qualitatively predicted by some theoretical explanations of the deep mixing
process.


title: Kramers degeneracy theorem in nonrelativistic QED

abstract:
  Degeneracy of the eigenvalues of the Pauli-Fierz Hamiltonian with spin 1/2 is
proven by the Kramers degeneracy theorem. The Pauli-Fierz Hamiltonian at fixed
total momentum is also investigated.


title: Search for charged massive long-lived particles with the D0 detector

abstract:
  We search for charged massive long-lived particles using 1.1 fb$^{-1}$ of
data collected by the D0 detector at the Fermilab Tevatron $p\bar{p}$ Collider.
Time-of-flight information is used to search for pair produced long-lived tau
sleptons, gaugino-like charginos, and higgsino-like charginos. We find no
evidence of a signal and set 95% C.L. cross section upper limits for staus,
which vary from 0.31pb to 0.04pb for stau masses between 60 GeV and 300 GeV. We
also set lower mass limits of 206 GeV (171 GeV) for pair produced charged
gauginos (higgsinos).


title:
Fermions and gauge bosons in $SU(4)_L \times U(1)_X$ models with little
  Higgs

abstract:
  We discuss the aspects of the little Higgs model with the $SU(4)_L \times
U(1)_X$ electroweak gauge group as an alternative solution to the naturalness
and fine-tuning issues. We introduce anomaly-free fermion spectra, and present
their interactions with the physical gauge bosons. We also discuss some
phenomenological implications of these fermions and the extra gauge bosons
based on recent experimental results.


title:
Probing the intrinsic state of a one-dimensional quantum well with a
  photon-assisted tunneling

abstract:
  The photon-assisted tunneling (PAT) through a single wall carbon nanotube
quantum well (QW) under influence an external electromagnetic field for probing
of the Tomonaga Luttinger liquid (TLL) state is suggested. The elementary TLL
excitations inside the quantum well are density ($\rho_{\pm}$) and spin
($\sigma_{\pm} $) bosons. The bosons populate the quantized energy levels
$\epsilon^{\rho +}_n =\Delta n/ g$ and $\epsilon^{\rho -(\sigma \pm)}_n =
\Delta n$ where $\Delta = h v_F /L $ is the interlevel spacing, $n$ is an
integer number, $L$ is the tube length, $g$ is the TLL parameter. Since the
electromagnetic field acts on the $\rho_{+}$ bosons only while the neutral
$\rho_{-}$ and $\sigma_{\pm} $ bosons remain unaffected, the PAT spectroscopy
is able of identifying the $\rho_{+}$ levels in the QW setup. The spin
$\epsilon_n^{\sigma+} $ boson levels in the same QW are recognized from Zeeman
splitting when applying a d.c. magnetic field $H \neq 0$ field. Basic TLL
parameters are readily extracted from the differential conductivity curves.


title: Discovery of A Very Bright, Strongly-Lensed z=2 Galaxy in the SDSS DR5

abstract:
  We report on the discovery of a very bright z = 2.00 star-forming galaxy that
is strongly lensed by a foreground z=0.422 luminous red galaxy (LRG). This
system was found in a systematic search for bright arcs lensed by LRGs and
brightest cluster galaxies in the Sloan Digital Sky Survey Data Release 5
sample. Follow-up observations on the Subaru 8.2m telescope on Mauna Kea and
the Astrophysical Research Consortium 3.5m telescope at Apache Point
Observatory confirmed the lensing nature of this system. A simple lens model
for the system, assuming a singular isothermal ellipsoid mass distribution,
yields an Einstein radius of 3.82 +/- 0.03 arcsec or 14.8 +/- 0.1 kpc/h at the
lens redshift. The total projected mass enclosed within the Einstein radius is
2.10 +/- 0.03 x 10^12 M_sun/h, and the magnification factor for the source
galaxy is 27 +/- 1. Combining the lens model with our gVriz photometry, we find
an (unlensed) star formation rate for the source galaxy of 32 M_sun/h / yr,
adopting a fiducial constant star formation rate model with an age of 100 Myr
and E(B-V) = 0.25. With an apparent magnitude of r = 19.9, this system is among
the very brightest lensed z >= 2 galaxies, and provides an excellent
opportunity to pursue detailed studies of the physical properties of an
individual high-redshift star-forming galaxy.


title: Directional photoelectric current across the bilayer graphene junction

abstract:
  A directional photon-assisted resonant chiral tunneling through a bilayer
graphene barrier is considered. An external electromagnetic field applied to
the barrier switches the transparency $T$ in the longitudinal direction from
its steady state value T=0 to the ideal T=1 at no energy costs. The switch
happens because the a.c. field affects the phase correlation between the
electrons and holes inside the graphene barrier changing the whole angular
dependence of the chiral tunneling (directional photoelectric effect). The
suggested phenomena can be implemented in relevant experiments and in various
sub-millimeter and far-infrared optical electronic devices.


title:
The second rational homology group of the moduli space of curves with
  level structures

abstract:
  Let $\Gamma$ be a finite-index subgroup of the mapping class group of a
closed genus $g$ surface that contains the Torelli group. For instance,
$\Gamma$ can be the level $L$ subgroup or the spin mapping class group. We show
that $H_2(\Gamma;\Q) \cong \Q$ for $g \geq 5$. A corollary of this is that the
rational Picard groups of the associated finite covers of the moduli space of
curves are equal to $\Q$. We also prove analogous results for surface with
punctures and boundary components.


title:
Three-dimensional N=8 conformal supergravity and its coupling to BLG
  M2-branes

abstract:
  This paper is concerned with the problem of coupling the N=8 superconformal
Bagger-Lambert-Gustavsson (BLG) theory to N=8 conformal supergravity in three
dimensions. We start by constructing the on-shell N=8 conformal supergravity in
three dimensions consisting of a Chern-Simons type term for each of the gauge
fields: the spin connection, the SO(8) R-symmetry gauge field and the spin 3/2
Rarita-Schwinger (gravitino) field. We then proceed to couple this theory to
the BLG theory. The final theory should have the same physical content, i.e.,
degrees of freedom, as the ordinary BLG theory. We discuss briefly the
properties of this "topologically gauged" BLG theory and why this theory may be
useful.


title:
Noncommutative Symmetric Functions VII: Free Quasi-Symmetric Functions
  Revisited

abstract:
  We prove a Cauchy identity for free quasi-symmetric functions and apply it to
the study of various bases. A free Weyl formula and a generalization of the
splitting formula are also discussed.


title: Inversion of some series of free quasi-symmetric functions

abstract:
  We give a combinatorial formula for the inverses of the alternating sums of
free quasi-symmetric functions of the form F_{\omega(I)} where I runs over
compositions with parts in a prescribed set C. This proves in particular three
special cases (no restriction, even parts, and all parts equal to 2) which were
conjectured by B. C. V. Ung in [Proc. FPSAC'98, Toronto].


title: Applications of patching to quadratic forms and central simple algebras

abstract:
  This paper provides applications of patching to quadratic forms and central
simple algebras over function fields of curves over henselian valued fields. In
particular, we use a patching approach to reprove and generalize a recent
result of Parimala and Suresh on the u-invariant of p-adic function fields, for
p odd. The strategy relies on a local-global principle for homogeneous spaces
for rational algebraic groups, combined with local computations.


title: Star-Planet Interactions

abstract:
  Much effort has been invested in recent years, both observationally and
theoretically, to understand the interacting processes taking place in
planetary systems consisting of a hot Jupiter orbiting its star within 10
stellar radii. Several independent studies have converged on the same scenario:
that a short-period planet can induce activity on the photosphere and upper
atmosphere of its host star. The growing body of evidence for such magnetic
star-planet interactions includes a diverse array of photometric, spectroscopic
and spectropolarimetric studies. The nature of which is modeled to be strongly
affected by both the stellar and planetary magnetic fields, possibly
influencing the magnetic activity of both bodies, as well as affecting
irradiation and non-thermal and dynamical processes. Tidal interactions are
responsible for the circularization of the planet orbit, for the
synchronization of the planet rotation with the orbital period, and may also
synchronize the outer convective envelope of the star with the planet. Studying
such star-planet interactions (SPI) aids our understanding of the formation,
migration and evolution of hot Jupiters.


title:
Charge order, dynamics, and magneto-structural transition in
  multiferroic LuFe$_2$O$_4$

abstract:
  We investigated the series of temperature and field-driven transitions in
LuFe$_2$O$_4$ by optical and M\"{o}ssbauer spectroscopies, magnetization, and
x-ray scattering in order to understand the interplay between charge,
structure, and magnetism in this multiferroic material. We demonstrate that
charge fluctuation has an onset well below the charge ordering transition,
supporting the "order by fluctuation" mechanism for the development of charge
order superstructure. Bragg splitting and large magneto optical contrast
suggest a low temperature monoclinic distortion that can be driven by both
temperature and magnetic field.


title: Llull and Copeland Voting Computationally Resist Bribery and Control

abstract:
  The only systems previously known to be resistant to all the standard control
types were highly artificial election systems created by hybridization. We
study a parameterized version of Copeland voting, denoted by Copeland^\alpha,
where the parameter \alpha is a rational number between 0 and 1 that specifies
how ties are valued in the pairwise comparisons of candidates. We prove that
Copeland^{0.5}, the system commonly referred to as "Copeland voting," provides
full resistance to constructive control, and we prove the same for
Copeland^\alpha, for all rational \alpha, 0 < \alpha < 1. Copeland voting is
the first natural election system proven to have full resistance to
constructive control. We also prove that both Copeland^1 (Llull elections) and
Copeland^0 are resistant to all standard types of constructive control other
than one variant of addition of candidates. Moreover, we show that for each
rational \alpha, 0 \leq \alpha \leq 1, Copeland^\alpha voting is fully
resistant to bribery attacks, and we establish fixed-parameter tractability of
bounded-case control for Copeland^\alpha. We also study Copeland^\alpha
elections under more flexible models such as microbribery and extended control
and we integrate the potential irrationality of voter preferences into many of
our results.


title: Precision Polarimetry at the International Linear Collider

abstract:
  The International Linear Collider (ILC) will collide polarised electrons and
positrons at beam energies of 45.6 GeV to 250 GeV and optionally up to 500 GeV.
To fully exploit the physics potential of this machine, not only the luminosity
and beam energy have to be known precisely, but also the polarisation of the
particles has to be measured with an unprecedented precision of dP/P ~ 0.25%
for both beams.
  An overall concept of high precision polarisation measurements at high beam
energies will be presented. The focus will be on the polarimeters (up- and
downstream of the e+e- interaction point) embedded in the ILC beam delivery
system. Some challenges concerning the design of the Compton spectrometers and
the appropriate Cherenkov detectors for each polarimeter are discussed.
Detailed studies of photodetectors and their readout electronics are presented
focusing specifically on the linearity of the device, since this is expected to
be the limiting factor on the precision of the polarisation measurement at the
ILC.


title:
Comparison of High-degree Solar Acoustic Frequencies and Asymmetry
  between Velocity and Intensity Data

abstract:
  Using the local helioseismic technique of ring diagram we analyze the
frequencies of high--degree f- and p-modes derived from both velocity and
continuum intensity data observed by MDI. Fitting the spectra with asymmetric
peak profiles, we find that the asymmetry associated with velocity line
profiles is negative for all frequency ranges agreeing with previous
observations while the asymmetry of the intensity profiles shows a complex and
frequency dependent behavior. We also observe systematic frequency differences
between intensity and velocity spectra at the high end of the frequency range,
mostly above 4 mHz. We infer that this difference arises from the fitting of
the intensity rather than the velocity spectra. We also show that the frequency
differences between intensity and velocity do not vary significantly from the
disk center to the limb when the spectra are fitted with the asymmetric profile
and conclude that only a part of the background is correlated with the
intensity oscillations.


title:
Top-antitop and Top-top Resonances in the Dilepton Channel at the CERN
  LHC

abstract:
  We perform a model-independent study for top-antitop and top-top resonances
in the dilepton channel at the Large Hadtron Collider. In this channel, we can
solve the kinematic system to obtain the momenta of all particles including the
two neutrinos, and hence the resonance mass and spin. For discovering
top-antitop resonances, the dilepton channel is competitive to the semileptonic
channel because of the good resolution of lepton momentum measurement and small
standard model backgrounds. Moreover, the charges of the two leptons can be
identified, which makes the dilepton channel advantageous for discovering
top-top resonances and for distinguishing resonance spins. We discuss and
provide resolutions for difficulties associated with heavy resonances and
highly boosted top quarks.


title:
Towards accurate modelling of the ISW effect, the non-linear
  contribution

abstract:
  In a universe with a cosmological constant, the large-scale gravitational
potential varies in time and this is, in principle, observable. Using an N-body
simulation of a $\Lambda$CDM universe, we show that linear theory is not
sufficiently accurate to predict the power spectrum of the time derivative,
$\dot{\Phi}$, needed to compute the imprint of large-scale structure on the
cosmic microwave background (CMB). The linear part of the $\dot{\Phi}$ power
spectrum (the integrated Sachs-Wolfe effect or ISW) drops quickly as the
relative importance of $\Omega_{\Lambda}$ diminishes at high redshift, while
the non-linear part (the Rees-Sciama effect or RS) evolves more slowly with
redshift. Therefore, the deviation of the total power spectrum from linear
theory occurs at larger scales at higher redshifts. The deviation occurs at
$k\sim 0.1 $ $h$ Mpc$^{-1}$ at $z=0$. The cross-correlation power spectrum of
the density $\delta$ with $\dot{\Phi}$ behaves differently to the power
spectrum of $\dot{\Phi}$. Firstly, the deviation from linear theory occurs at
smaller scales ($k\sim 1 $ $h$ Mpc$^{-1}$ at $z=0$). Secondly, the correlation
becomes negative when the non-linear effect dominates. For the
cross-correlation power spectrum of galaxy samples with the CMB, the non-linear
effect becomes significant at $l\sim 500$ and rapidly makes the cross power
spectrum negative. For high redshift samples, the cross-correlation is expected
to be suppressed by $5-10%$ on arcminute scales. The RS effect makes a
negligible contribution to the large-scale ISW cross-correlation measurement.
However, on arc-minute scales it will contaminate the expected
cross-correlation signal induced by the Sunyaev-Zel'dovich effect.


title: Using Millimeter VLBI to Constrain RIAF Models of Sagittarius A*

abstract:
  The recent detection of Sagittarius A* at lambda = 1.3 mm on a baseline from
Hawaii to Arizona demonstrates that millimeter wavelength very long baseline
interferometry (VLBI) can now spatially resolve emission from the innermost
accretion flow of the Galactic center region. Here, we investigate the ability
of future millimeter VLBI arrays to constrain the spin and inclination of the
putative black hole and the orientation of the accretion disk major axis within
the context of radiatively inefficient accretion flow (RIAF) models. We examine
the range of baseline visibility and closure amplitudes predicted by RIAF
models to identify critical telescopes for determining the spin, inclination,
and disk orientation of the Sgr A* black hole and accretion disk system. We
find that baseline lengths near 3 gigalambda have the greatest power to
distinguish amongst RIAF model parameters, and that it will be important to
include new telescopes that will form north-south baselines with a range of
lengths. If a RIAF model describes the emission from Sgr A*, it is likely that
the orientation of the accretion disk can be determined with the addition of a
Chilean telescope to the array. Some likely disk orientations predict
detectable fluxes on baselines between the continental United States and even a
single 10-12 m dish in Chile. The extra information provided from closure
amplitudes by a four-antenna array enhances the ability of VLBI to discriminate
amongst model parameters.


title: Estimating the Parameters of Sgr A*'s Accretion Flow Via Millimeter VLBI

abstract:
  Recent millimeter-VLBI observations of Sagittarius A* (Sgr A*) have, for the
first time, directly probed distances comparable to the horizon scale of a
black hole. This provides unprecedented access to the environment immediately
around the horizon of an accreting black hole. We leverage both existing
spectral and polarization measurements and our present understanding of
accretion theory to produce a suite of generic radiatively inefficient
accretion flow (RIAF) models of Sgr A*, which we then fit to these recent
millimeter-VLBI observations. We find that if the accretion flow onto Sgr A* is
well described by a RIAF model, the orientation and magnitude of the black
hole's spin is constrained to a two-dimensional surface in the spin,
inclination, position angle parameter space. For each of these we find the
likeliest values and their 1-sigma & 2-sigma errors to be a=0(+0.4+0.7),
inclination=50(+10+30)(-10-10) degrees, and position angle=-20(+31+107)(-16-29)
degrees, when the resulting probability distribution is marginalized over the
others. The most probable combination is a=0(+0.2+0.4), inclination=90(-40-50)
degrees and position angle=-14(+7+11)(-7-11) degrees, though the uncertainties
on these are very strongly correlated, and high probability configurations
exist for a variety of inclination angles above 30 degrees and spins below
0.99. Nevertheless, this demonstrates the ability millimeter-VLBI observations,
even with only a few stations, to significantly constrain the properties of Sgr
A*.


title:
On surface brightness fluctuations: probabilistic and statistical bases
  I: Stellar population and theoretical SBF

abstract:
  This work aims to provide a theoretical formulation of Surface Brightness
Fluctuations (SBF) in the framework of probabilistic synthesis models, and to
distinguish between the different distributions involved in the SBF definition.
RESULTS: We propose three definitions of SBF: (i) stellar population SBF, which
can be computed from synthesis models and provide an intrinsic metric of fit
for stellar population studies; (ii) theoretical SBF, which include the stellar
population SBF plus an additional term that takes into account the distribution
of the number of stars per resolution element psi(N); theoretical SBF coincide
with Tonry & Schneider (1998) definition in the very particular case that
psi(N) is assumed to be a Poisson distribution. However, the Poisson
contribution to theoretical SBF is around 0.1% of the contribution due to the
stellar population SBF, so there is no justification to include any reference
to Poisson statistics in the SBF definition; (iii) observational SBF, which are
those obtained in observations that are distributed around the theoretical SBF.
Finally, we show alternative ways to compute SBF and extend the application of
stellar population SBF to defining a metric of fitting for standard stellar
population studies. CONCLUSIONS: We demostrate that SBF are observational
evidence of a probabilistic paradigm in population synthesis, where integrated
luminosities have an intrinsic distributed nature, and they rule out the
commonly assumed deterministic paradigm of stellar population modeling.


title: A New Approach to mu-Bmu

abstract:
  We present a new approach to the mu-Bmu problem of gauge mediated
supersymmetry breaking. Rather than reducing the generically large contribution
to Bmu we point out that acceptable electroweak symmetry breaking can be
achieved with mu^2 << Bmu if at the same time Bmu << m_Hd^2. This hierarchy can
easily appear in models where the Higgs fields are directly coupled to the
supersymmetry breaking sector. Such models can yield novel electroweak symmetry
breaking vacua, can deal with the supersymmetric flavor and CP problems, allow
for gauge coupling unification, and result in distinct phenomenological
predictions for the spectrum of superparticles.


title: The ionizing background at the end of overlap

abstract:
  One of the most sought-after signatures of reionization is a rapid increase
in the ionizing background (usually measured through the Lyman-alpha optical
depth toward distant quasars). Conventional wisdom associates this with the
"overlap" phase when ionized bubbles merge, allowing each source to affect a
much larger volume. We argue that this picture fails to describe the transition
to the post-overlap Universe, where Lyman-limit systems absorb ionizing photons
over moderate lengthscales (20-100 Mpc). Using an analytic model, we compute
the probability distribution of the amplitude of the ionizing background
throughout reionization, including both discrete ionized bubbles and
Lyman-limit systems (parameterized by an attenuation length). We show that
overlap does not by itself cause a rapid increase in the ionizing background or
a rapid decrease in the mean Lyman-alpha transmission toward distant quasars.
More detailed semi-numeric models support these conclusions. We argue that
rapid changes should instead be interpreted as evolution in the attenuation
length itself, which may or may not be directly related to overlap.


title: Supercurrent: Vector Hair for an AdS Black Hole

abstract:
  In arXiv:0803.3295 [hep-th] a holographic black hole solution is discussed
which exhibits a superconductor like transition. In the superconducting phase
the black holes show infinite DC conductivity. This gives rise to the
possibility of deforming the solutions by turning on a time independent current
(supercurrent), without any electric field. This type of deformation does not
exist for normal (non-superconducting) black holes, due to the no-hair
theorems. In this paper we have studied such a supercurrent solution and the
associated phase diagram. Interestingly, we have found a "special point"
(critical point) in the phase diagram where the second order superconducting
phase transition becomes first order. Supercurrent in superconducting materials
is a well studied phenomenon in condensed matter systems. We have found some
qualitative agreement with known results.


title: Gravitational fields as generalized string models

abstract:
  We show that Einstein's main equations for stationary axisymmetric fields in
vacuum are equivalent to the motion equations for bosonic strings moving on a
special nonflat background. This new representation is based on the analysis of
generalized harmonic maps in which the metric of the target space explicitly
depends on the parametrization of the base space. It is shown that this
representation is valid for any gravitational field which possesses two
commuting Killing vector fields. We introduce the concept of dimensional
extension which allows us to consider this type of gravitational fields as
strings embedded in D-dimensional nonflat backgrounds, even in the limiting
case where the Killing vector fields are hypersurface orthogonal.


title: Dominated polynomials on infinite dimensional spaces

abstract:
  The aim of this paper is to prove a stronger version of a conjecture on the
existence of non-dominated scalar-valued m-homogeneous polynomials (m>=3) on
arbitrary infinite dimensional Banach spaces.


title: SIMP: A Near-Infrared Proper Motion Survey

abstract:
  SIMP is a proper motion (PM) survey made with the Observatoire du Mont
Megantic (OMM) wide-field near-infrared camera CPAPIR at the CTIO 1.5 m and OMM
1.6 m telescopes. The SIMP observations were initiated in early 2005, are still
ongoing and, to date, have covered 28% of the sky at high galactic latitudes.
The PMs of the sources detected are determined by comparing their measured
positions with those listed in the 2MASS point source catalog, giving a time
baseline of 4 to 10 years. The 5 sigma uncertainty on the relative SIMP and
2MASS astrometry is 1", equivalent to a PM lower limit of 0.125-0.250"/yr, or a
tangential velocity limit of 15-30 km/s at 25 pc. Up to the 2MASS magnitude
limit (J~16.5), T dwarfs are found out to ~25 pc, while L dwarfs may be found
as far as 100 pc away.


title: Doping single wall carbon nanotubes with differently charged porphyrins

abstract:
  Photoluminescence (PL) measurements of porphyrin-doped single wall carbon
nanotubes (SWNT) were studied in sodium dodecylbenzenesulfonate (NaDDBS)
aqueous dispersions. The PL spectra were used to draw PL maps were the maxima
corresponds to absorption-emission excitonic processes related to (E11, E22)
first Van Hove singularities of the SWNT electronic structure. The influence of
the net charge of the porphyrin was a determinant factor in the energy map
maximum shifts (EMMS) compared to the energy map of a pristine NaDDBS/SWNT
dispersion. A non-interacting porphyrin is used as a reference to discard the
influence of the dielectric constant of the medium in the EMMS.


title:
A Possible Approach to Inclusion of Space and Time in Frame Fields of
  Quantum Representations of Real and Complex Numbers

abstract:
  This work is based on the field of reference frames based on quantum
representations of real and complex numbers described in other work. Here frame
domains are expanded to include space and time lattices. Strings of qukits are
described as hybrid systems as they are both mathematical and physical systems.
As mathematical systems they represent numbers. As physical systems in each
frame the strings have a discrete Schrodinger dynamics on the lattices. The
frame field has an iterative structure such that the contents of a stage j
frame have images in a stage j-1 (parent) frame. A discussion of parent frame
images includes the proposal that points of stage j frame lattices have images
as hybrid systems in parent frames. The resulting association of energy with
images of lattice point locations, as hybrid systems states, is discussed.
Representations and images of other physical systems in the different frames
are also described.


title:
Characterization of the Oblique Projector $U(VU)^+V$ with Application to
  Constrained Least Squares

abstract:
  We provide a full characterization of the oblique projector $U(VU)^+V$ in the
general case where the range of $U$ and the null space of $V$ are not
complementary subspaces. We discuss the new result in the context of
constrained least squares minimization.


title: Audio Classification from Time-Frequency Texture

abstract:
  Time-frequency representations of audio signals often resemble texture
images. This paper derives a simple audio classification algorithm based on
treating sound spectrograms as texture images. The algorithm is inspired by an
earlier visual classification scheme particularly efficient at classifying
textures. While solely based on time-frequency texture features, the algorithm
achieves surprisingly good performance in musical instrument classification
experiments.


title: Entanglement entropy in SU(N) gauge theory

abstract:
  The entanglement entropy of SU(N) lattice gauge theory is studied exactly in
1+1 space-time dimensions and in Migdal-Kadanoff approximation in higher
dimensional space. The existence of a non-analytical behavior reminiscent of a
phase transition for a characteristic size of the entangled region is
demonstrated for higher dimensional theories.


title: Lessons from Random Matrix Theory for QCD at Finite Density

abstract:
  In this lecture we discuss various aspects of QCD at nonzero chemical
potential, including its phase diagram and the Dirac spectrum, and summarize
what chiral random matrix theory has contributed to this subject. To illustrate
the importance of the phase of the fermion determinant, we particularly
highlight the differences between QCD and phase quenched QCD.


title:
Molecular cloud chemistry and the importance of dielectronic
  recombination

abstract:
  Dielectronic recombination (DR) of singly charged ions is a reaction pathway
that is commonly neglected in chemical models of molecular clouds. In this
study we include state-of-the-art DR data for He$^+$, C$^+$, N$^+$, O$^+$,
Na$^+$, and Mg$^+$ in chemical models used to simulate dense molecular clouds,
protostars, and diffuse molecular clouds. We also update the radiative
recombination (RR) rate coefficients for H$^+$, He$^+$, C$^+$, N$^+$, O$^+$,
Na$^+$, and Mg$^+$ to the current state-of-the-art values. The new RR data has
little effect on the models. However, the inclusion of DR results in
significant differences in gas-grain models of dense, cold molecular clouds for
the evolution of a number of surface and gas-phase species. We find differences
of a factor of 2 in the abundance for 74 of the 655 species at times of
$10^4$--$10^6$ years in this model when we include DR. Of these 74 species, 16
have at least a factor of 10 difference in abundance. We find the largest
differences for species formed on the surface of dust grains. These differences
are due primarily to the addition of C$^+$ DR, which increases the neutral C
abundance, thereby enhancing the accretion of C onto dust. These results may be
important for the warm-up phase of molecular clouds when surface species are
desorbed into the gas phase. We also note that no reliable state-of-the-art RR
or DR data exist for Si$^+$, P$^+$, S$^+$, Cl$^+$, and Fe$^+$. Modern
calculations for these ions are needed to better constrain molecular cloud
models.


title:
Constraining the LRG Halo Occupation Distribution using
  Counts-in-Cylinders

abstract:
  The low number density of the Sloan Digital Sky Survey (SDSS) Luminous Red
Galaxies (LRGs) suggests that LRGs occupying the same dark matter halo can be
separated from pairs occupying distinct dark matter halos with high fidelity.
We present a new technique, Counts-in-Cylinders (CiC), to constrain the
parameters of the satellite contribution to the LRG Halo-Occupation
Distribution (HOD). For a fiber collision-corrected SDSS spectroscopic LRG
subsample at 0.16 < z < 0.36, we find the CiC multiplicity function is fit by a
halo model where the average number of satellites in a halo of mass M is
<Nsat(M)> = ((M - Mcut)/M1)^alpha with Mcut = 5.0 +1.5/-1.3 (+2.9/-2.6) X 10^13
Msun, M1 = 4.95 +0.37/-0.26 (+0.79/-0.53) X 10^14 Msun, and alpha = 1.035
+0.10/-0.17 (+0.24/-0.31) at the 68% and 95% confidence levels using a WMAP3
cosmology and z=0.2 halo catalog.
  Our method tightly constrains the fraction of LRGs that are satellite
galaxies, 6.36 +0.38/-0.39, and the combination Mcut/10^{14} Msun + alpha =
1.53 +0.08/-0.09 at the 95% confidence level. We also find that mocks based on
a halo catalog produced by a spherical overdensity (SO) finder reproduce both
the measured CiC multiplicity function and the projected correlation function,
while mocks based on a Friends-of-Friends (FoF) halo catalog has a deficit of
close pairs at ~1 Mpc/h separations. Because the CiC method relies on higher
order statistics of close pairs, it is robust to the choice of halo finder. In
a companion paper we will apply this technique to optimize Finger-of-God (FOG)
compression to eliminate the 1-halo contribution to the LRG power spectrum.


title: On a possible connection between Chandler wobble and dark matter

abstract:
  Chandler wobble excitation and damping, one of the open problems in
geophysics, is treated as a consequence in part of the interaction between
Earth and a hypothetical oblate ellipsoid made of dark matter. The physical and
geometrical parameters of such an ellipsoid and the interacting torque strength
is calculated in such a way to reproduce the Chandler wobble component of the
polar motion in several epochs, available in the literature. It is also
examined the consequences upon the geomagnetic field dynamo and generation of
heat in the Earth outer core.


title:
On the consequences of twisted Poincare' symmetry upon QFT on Moyal
  noncommutative spaces

abstract:
  We explore some general consequences of a consistent formulation of
relativistic quantum field theory (QFT) on the Groenewold-Moyal-Weyl
noncommutative versions of Minkowski space with covariance under the twisted
Poincare' group of Chaichian et al. [12], Wess [44], Koch et al. [31], Oeckl
[34]. We argue that a proper enforcement of the latter requires braided
commutation relations between any pair of coordinates $\hat x,\hat y$
generating two different copies of the space, or equivalently a $\star$-tensor
product $f(x)\star g(y)$ (in the parlance of Aschieri et al. [3]) between any
two functions depending on $x,y$. Then all differences $(x-y)^\mu$ behave like
their undeformed counterparts. Imposing (minimally adapted) Wightman axioms one
finds that the $n$-point functions fulfill the same general properties as on
commutative space. Actually, upon computation one finds (at least for scalar
fields) that the $n$-point functions remain unchanged as functions of the
coordinates' differences both if fields are free and if they interact (we treat
interactions via time-ordered perturbation theory). The main, surprising
outcome seems a QFT physically equivalent to the undeformed counterpart (to
confirm it or not one should however first clarify the relation between
$n$-point functions and observables, in particular S-matrix elements).
  These results are mainly based on a joint work [24] with J. Wess


title: Dirac constraints in field theory and exterior differential systems

abstract:
  The usual treatment of a (first order) classical field theory such as
electromagnetism has a little drawback: It has a primary constraint submanifold
that arise from the fact that the dynamics is governed by the antisymmetric
part of the jet variables. So it is natural to ask if there exists a
formulation of this kind of field theories which avoids this problem, retaining
the versatility of the known approach. The following paper deals with a family
of variational problems, namely, the so called non standard variational
problems, which intends to capture the data necessary to set up such a
formulation for field theories; moreover, we will formulate a multisymplectic
structure for the family of non standard variational problems, and we will
relate this with the (pre)symplectic structure arising on the space of sections
of the bundle of fields. In this setting the Dirac theory of constraints will
be studied, obtaining among other things a novel characterization of the
constraint manifold which arises in this theory, as generators of an exterior
differential system associated to the equations of motion and the chosen
slicing. Several examples of application of this formalism are discussed: Two
of them motivated from the physical point of view, that is, electromagnetism
and Poisson sigma models, and two examples of mathematical application. In the
case of electromagnetism, it is shown that this formulation avoids the problems
arising in the usual approach.


title: Two Essays on the Archimedean versus Non-Archimedean Debate

abstract:
  Part 1 : For more than two millennia, ever since Euclid's geometry, the so
called Archimedean Axiom has been accepted without sufficiently explicit
awareness of that fact. The effect has been a severe restriction of our views
of space-time, a restriction which above all affects Physics. Here it is argued
that, ever since the invention of Calculus by Newton, we may actually have {\it
empirical evidence} that time, and thus space as well, are not Archimedean.
  Part 2 : There is an insufficient awareness about the {\it rich and complex}
structure of various totally ordered scalar fields obtained through the {\it
ultrapower} construction. This rich and complex structure comes from the
presence of {\it infinitesimals} in such fields, presence which leads to the
fact that such fields are {\it non-Archimedean}. Here, with the concept of {\it
walkable world}, which has highly intuitive and pragmatic geometric meaning,
the mentioned rich and complex structure is illustrated. The issues presented
have relevance for what are usually called the "infinities in physics".


title: Critical behavior at edge singularities in one dimensional spin models

abstract:
  In ferromagnetic spin models above the critical temperature ($T > T_{cr}$)
the partition function zeros accumulate at complex values of the magnetic field
($H_E$) with a universal behavior for the density of zeros $\rho (H) \sim | H -
H_E |^{\sg}$. The critical exponent $\sg$ is believed to be universal at each
space dimension and it is related to the magnetic scaling exponent $y_h$ via
$\sg = (d-y_h)/y_h$. In two dimensions we have $y_h=12/5 (\sg = -1/6)$ while
$y_h=2 (\sg=-1/2)$ in $d=1$. For the one dimensional Blume-Capel and
Blume-Emery-Griffiths models we show here, for different temperatures, that a
new value $y_h=3 (\sg =-2/3)$ can emerge if we have a triple degeneracy of the
transfer matrix eigenvalues.


title: An edge index for the Quantum Spin-Hall effect

abstract:
  Quantum Spin-Hall systems are topological insulators displaying
dissipationless spin currents flowing at the edges of the samples. In
contradistinction to the Quantum Hall systems where the charge conductance of
the edge modes is quantized, the spin conductance is not and it remained an
open problem to find the observable whose edge current is quantized. In this
paper, we define a particular observable and the edge current corresponding to
this observable. We show that this current is quantized and that the
quantization is given by the index of a certain Fredholm operator. This
provides a new topological invariant that is shown to take same values as the
Spin-Chern number previously introduced in the literature. The result gives an
effective tool for the investigation of the edge channels' structure in Quantum
Spin-Hall systems. Based on a reasonable assumption, we also show that the edge
conducting channels are not destroyed by a random edge.

categories: cond-mat.mes-hall cond-mat.stat-mech math-ph math.MP


title:
Conformal Field Theory as Microscopic Dynamics of Incompressible Euler
  and Navier-Stokes Equations

abstract:
  We consider the hydrodynamics of relativistic conformal field theories at
finite temperature. We show that the limit of slow motions of the ideal
hydrodynamics leads to the non-relativistic incompressible Euler equation. For
viscous hydrodynamics we show that the limit of slow motions leads to the
non-relativistic incompressible Navier-Stokes equation. We explain the physical
reasons for the reduction and discuss the implications. We propose that
conformal field theories provide a fundamental microscopic viewpoint of the
equations and the dynamics governed by them.


title:
Dynamics with Infinitely Many Derivatives: Variable Coefficient
  Equations

abstract:
  Infinite order differential equations have come to play an increasingly
significant role in theoretical physics. Field theories with infinitely many
derivatives are ubiquitous in string field theory and have attracted interest
recently also from cosmologists. Crucial to any application is a firm
understanding of the mathematical structure of infinite order partial
differential equations. In our previous work we developed a formalism to study
the initial value problem for linear infinite order equations with constant
coefficients. Our approach relied on the use of a contour integral
representation for the functions under consideration. In many applications,
including the study of cosmological perturbations in nonlocal inflation, one
must solve linearized partial differential equations about some time-dependent
background. This typically leads to variable coefficient equations, in which
case the contour integral methods employed previously become inappropriate. In
this paper we develop the theory of a particular class of linear infinite order
partial differential equations with variable coefficients. Our formalism is
particularly well suited to the types of equations that arise in nonlocal
cosmological perturbation theory. As an example to illustrate our formalism we
compute the leading corrections to the scalar field perturbations in p-adic
inflation and show explicitly that these are small on large scales.


title: Spectroscopy with dynamical Chirally Improved quarks

abstract:
  We present recent results of our dynamical simulations with Chirally Improved
fermions and report on new developments in the determination of excited
light-quark meson states using interpolators constructed by applying covariant
derivatives on Jacobi-smeared quark sources within the framework of the
variational method.


title: Local smoothing effects for the water-wave problem with surface tension

abstract: This paper has been merged to 0908.3255.


title: Kinematical & Chemical Characteristics of the Thin and Thick Disks

abstract:
  I discuss how the chemical abundance distributions, kinematics and age
distributions of stars in the thin and thick disks of the Galaxy can be used to
decipher the merger history of the Milky Way, a typical large galaxy. The
observational evidence points to a rather quiescent past merging history,
unusual in the context of the `consensus' cold-dark-matter cosmology favoured
from observations of structure on scales larger than individual galaxies.


title: KBS 13 -- a Rare Reflection Effect sdB Binary with an M Dwarf Secondary

abstract:
  We report preliminary VRI differential photometric and spectroscopic results
for KBS 13, a recently discovered non-eclipsing sdB+dM system. Radial velocity
measurements indicate an orbital period of 0.2923 +/- 0.0004 days with a
semi-amplitude velocity of 22.82 +/- 0.23 km s-1. This suggests the smallest
secondary minimum mass yet found. We discuss the distribution of orbital
periods and secondary minimum masses for other similar systems.


title: Global Dimension of Polynomial Rings in Partially Commuting Variables

abstract:
  For any free partially commutative monoid $M(E,I)$, we compute the global
dimension of the category of $M(E,I)$-objects in an Abelian category with exact
coproducts. As a corollary, we generalize Hilbert's Syzygy Theorem to
polynomial rings in partially commuting variables.


title: Equidistribution of Dilations of Polynomial Curves in Nilmanifolds

abstract:
  In this paper we study the asymptotic behaviour under dilations of
probability measures supported on polynomial curves in nilmanifolds. We prove,
under some mild conditions, effective equidistribution of such measures to the
Haar measure. We also formulate a mean ergodic theorem for
$\R^n$-representations on Hilbert spaces, restricted to a moving phase of low
dimension. Furthermore, we bound the necessary dilation of a given smooth curve
in $ \R^n$ so that the canonical projection onto $ \T^n $ is $ \eps$-dense.


title: Rescaled Lotka-Volterra Models Converge to Super Stable Processes

abstract:
  Recently, it has been shown that stochastic spatial Lotka-Volterra models
when suitably rescaled can converge to a super Brownian motion. We show that
the limit process could be a super stable process if the kernel of the
underlying motion is in the domain of attraction of a stable law. The
corresponding results in Brownian setting were proved by Cox and Perkins (2005,
2008). As applications of the convergence theorems, some new results on the
asymptotics of the voter model started from single 1 at the origin are obtained
which improve the results by Bramson and Griffeath (1980).


title: Calogero-Moser Spaces over Algebraic Curves

abstract:
  In these notes, we give a survey of the main results of [BC] and [BW]. Our
aim is to generalize the geometric classification of (one-sided) ideals of the
first Weyl algebra $ A_1(C) $ (see [BW1, BW2]) to the ring $ D(X) $ of
differential operators on an arbitrary complex smooth affine curve X. We
approach this problem in two steps: first, we classify the ideals of D(X) up to
stable isomorphism, in terms of the Picard group of X; then, we refine this
classification by describing each stable isomorphism class as a disjoint union
of (certain quotients of) generalized Calogero-Moser spaces C_n(X, I). The
latter are defined as representation varieties of deformed preprojective
algebras over a one-point extension of the ring of regular functions on X by
the line bundle I. As in the classical case, C_n(X, I) turn out to be smooth
irreducible varieties of dimension 2n.


title:
Isomorphic classical molecular dynamics model for an excess electron in
  a supercritical fluid

abstract:
  Ring polymer molecular dynamics (RPMD) is used to directly simulate the
dynamics of an excess electron in a supercritical fluid over a broad range of
densities. The accuracy of the RPMD model is tested against numerically exact
path integral statistics through the use of analytical continuation techniques.
At low fluid densities, the RPMD model substantially underestimates the
contribution of delocalized states to the dynamics of the excess electron.
However, with increasing solvent density, the RPMD model improves, nearly
satisfying analytical continuation constraints at densities approaching those
of typical liquids. In the high density regime, quantum dispersion
substantially decreases the self-diffusion of the solvated electron.
  In this regime where the dynamics of the electron is strongly coupled to the
dynamics of the atoms in the fluid, trajectories that can reveal diffusive
motion of the electron are long in comparison to $\beta\hbar$.


title: Turbulence: A Probe of the Dynamics and Physics of the Magellanic Stream

abstract:
  A recent paper by Stanimirovic etal (2008) presents quit interesting results
from HI observations of the Magellanic Stream (MS) tip. The high spatial
resolution of the data reveals rich and complex morphological and kinematic
structures; notably four coherent HI substreams extending over angular size of
about 20 deg were found.
  We use the position-velocity images of Stanimirovic etal (2008) to derive
spatial power spectra for the velocity residuals. These, indicate the presence
of a large scale turbulence with size comparable to that of the streams
themselves. The turbulent velocity on the largest scale is estimated to be
about 15 km/s . Adopting, a distance of 120 kpc, implies a turbulent largest
scale of 40 kpc and timescale for decay of about 3 Gyr. For a turbulence with
scale that large, the natural energy source is the tidal interaction between
the Magellanic Clouds, and between them and the Milky Way galaxy. The shape of
derived turbulence spectrum is used here to obtain constraints on the
inclination of the streams and on the density of the emitting neutral hydrogen.


title: Beryllium Abundances in Stars of One-Solar-Mass

abstract:
  We have determined Be abundances in 50 F and G dwarfs in the mass range of
0.9 $\leq$ M$_\odot$ $\leq$ 1.1 as determined by Lambert & Reddy. The effective
temperatures are 5600 to 6400 K and metallicities from $-$0.65 to +0.11. The
spectra were taken primarily with Keck I + HIRES. The Be abundances were found
via spectral synthesis of Be II lines near 3130 \AA. The Be abundances were
investigated as a function of age, temperature, metallicity and Li abundance in
this narrow mass range. Even though our stars are similar in mass, they show a
range in Be abundances of a factor of $>$40. We find that [Be/Fe] has no
dependence on temperature, but does show a spread of a factor of 6 at a given
temperature. The reality of the spread is shown by two identical stars which
differ from each other by a factor of two only in their abundances of Li and
Be. Our thin-disk-star sample fits the trend between Be abundance and [Fe/H]
found for halo and thick disk stars, extending it to about 4 orders of
magnitude in the two logarithmic quantities. Both Fe and Be appear to increase
similarly over time in the Galaxy. One-third of our sample may be classified as
subgiants; these more-evolved stars have lower Be abundances than the dwarfs.
They have undergone Be depletion by slow mixing on the main sequence and Be
dilution during their trip toward the red giant base. There are both Li and Be
detections in 60 field stars in the "Li-plateau" of 5900 - 6300 K now and the
abundances of the two light elements are correlated with a slope of 0.34
$\pm$0.05, with greater Li depletion than Be depletion.


title: Compositions of consistent systems of rank one discrete valuation rings

abstract:
  Let V be a rank one discrete valuation ring (DVR) on a field F and let L/F be
a finite separable algebraic field extension with [L:F] = m. The integral
closure of V in L is a Dedekind domain that encodes the following invariants:
(i) the number of extensions of V to a valuation ring W on L, (ii) the residue
degree of each W over V, and (iii) the ramification degree of each W over V.
Given a finite set of DVRs on F, an m-consistent system is a family of sets
enumerating what is theoretically possible for the above invariants of each V
in the set. The m-consistent system is realizable if there exists a finite
separable extension field L/F that gives for each V the listed invariants. We
investigate the realizability of m-consistent systems.


title: Fundamental Theorem of Calculus

abstract:
  A simple but rigorous proof of the Fundamental Theorem of Calculus is given
in geometric calculus, after the basis for this theory in geometric algebra has
been explained. Various classical examples of this theorem, such as the Green's
and Stokes' theorem are discussed, as well as the new theory of monogenic
functions, which generalizes the concept of an analytic function of a complex
variable to higher dimensions.


title:
Global existence for compressible Navier-Stokes-Poisson equations in
  three and higher dimensions

abstract:
  The compressible Navier-Stokes-Poisson system is concerned in the present
paper, and the global existence and uniqueness of the strong solution is shown
in the framework of hybrid Besov spaces in three and higher dimensions.


title:
Connection between Coulomb and harmonic oscillator potentials in
  relativistic quantum mechanics

abstract:
  The Levi-Civita transformation is applied in the two-dimensional (2D) Dirac
and Klein-Gordon (KG) equations with equal external scalar and vector
potentials. The Coulomb and harmonic oscillator problems are connected via the
Levi-Civita transformation. These connections lead to an approach to solve the
Coulomb problems using the results of the harmonic oscillator potential in the
above-mentioned relativistic systems.


title:
The Equivalence of Semidefinite Relaxation MIMO Detectors for
  Higher-Order QAM

abstract:
  In multi-input-multi-output (MIMO) detection, semidefinite relaxation (SDR)
has been shown to be an efficient high-performance approach. Developed
initially for BPSK and QPSK, SDR has been found to be capable of providing
near-optimal performance (for those constellations). This has stimulated a
number of recent research endeavors that aim to apply SDR to the high-order QAM
cases. These independently developed SDRs are different in concept and
structure, and presently no serious analysis has been given to compare these
methods. This paper analyzes the relationship of three such SDR methods, namely
the polynomial-inspired SDR (PI-SDR) by Wiesel et al., the bound-constrained
SDR (BC-SDR) by Sidiropoulos and Luo, and the virtually-antipodal SDR (VA-SDR)
by Mao et al. The result that we have proven is somehow unexpected: the three
SDRs are equivalent. Simply speaking, we show that solving any one SDR is
equivalent to solving the other SDRs. This paper also discusses some
implications arising from the SDR equivalence, and provides simulation results
to verify our theoretical findings.


title: Mining Meaning from Wikipedia

abstract:
  Wikipedia is a goldmine of information; not just for its many readers, but
also for the growing community of researchers who recognize it as a resource of
exceptional scale and utility. It represents a vast investment of manual effort
and judgment: a huge, constantly evolving tapestry of concepts and relations
that is being applied to a host of tasks.
  This article provides a comprehensive description of this work. It focuses on
research that extracts and makes use of the concepts, relations, facts and
descriptions found in Wikipedia, and organizes the work into four broad
categories: applying Wikipedia to natural language processing; using it to
facilitate information retrieval and information extraction; and as a resource
for ontology building. The article addresses how Wikipedia is being used as is,
how it is being improved and adapted, and how it is being combined with other
structures to create entirely new resources. We identify the research groups
and individuals involved, and how their work has developed in the last few
years. We provide a comprehensive list of the open-source software they have
produced.


title: Synchrony-optimized Networks of Non-identical Kuramoto Oscillators

abstract:
  In this letter we discuss a method for generating synchrony-optimized
coupling architectures of Kuramoto oscillators with a heterogeneous
distribution of native frequencies. The method allows us to relate the
properties of the coupling network to its synchronizability. These relations
were previously only established from a linear stability analysis of the
identical oscillator case. We further demonstrate that the heterogeneity in the
oscillator population produces heterogeneity in the optimal coupling network as
well. Two rules for enhancing the synchronizability of a given network by a
suitable placement of oscillators are given: (i) native frequencies of adjacent
oscillators must be anti-correlated and (ii) frequency magnitudes should
positively correlate with the degree of the node they are placed at.


title: Topological meaning of Z$_2$ numbers in time reversal invariant systems

abstract:
  We show that the Z$_2$ invariant, which classifies the topological properties
of time reversal invariant insulators, has deep relationship with the global
anomaly. Although the second Chern number is the basic topological invariant
characterizing time reversal systems, we show that the relative phase between
the Kramers doublet reduces the topological quantum number Z to Z$_2$.


title: Speckle instability: coherent effects in nonlinear disordered media

abstract:
  We numerically investigate the properties of speckle patterns formed by
nonlinear point scatterers. We show that, in the weak localization regime,
dynamical instability appears, eventually leading to chaotic behavior of the
system. Analysing the statistical properties of the instability thresholds for
different values of the system size and disorder strength, a scaling law is
emphasized. The later is also found to govern the smallest decay rate of the
linear system, putting thus forward the crucial importance of interference
effects. This is also underlined by the fact that coherent backscattering is
still observed even in the chaotic regime.

categories: cond-mat.mes-hall nlin.CD physics.atom-ph quant-ph


title:
Combining photoemission and optical spectroscopies for reliable valence
  determination in YbS and Yb metal

abstract:
  Hard x-ray photoemission and optical spectroscopies have been performed on
YbS and Yb metal to determine the precise $f$-electron occupation. A comparison
of the photoemission spectra with the energy loss functions in bulk and
surface, obtained from optical reflectivity, enables us to distinguish between
the energy loss satellite of Yb$^{2+}$ peak and Yb$^{3+}$ multiplet. The
results clearly indicate a purely divalent Yb state except for the surface of
YbS. We demonstrate that the present method is highly reliable in identifying
the electronic structure and the mean valence in $f$-electron systems.


title: Exact Chiral Fermions and Finite Density on Lattice

abstract:
  Any mu^2-divergence is shown analytically to be absent for a class of actions
for Overlap and Domain Wall Fermions with nonzero chemical potential. All such
actions are, however, shown to violate the chiral invariance. While the
parameter M of these actions can be shown to be irrelevant in the continuum
limit, as expected, it is shown numerically that the continuum limit can be
reached with relatively coarser lattices for M in the range of 1.5-1.6.


title: A class of inflation models with non-minimal coupling

abstract:
  We show that the potential of the scalar field in the Einstein frame is flat
if the nonminimal coupling term is properly chosen that it satisfies the
condition (V(phi)/K^2(phi)-> constant) as phi gets large. The cosmological
implication of this theory is studied.


title:
Reconstruction of the primordial fluctuation spectrum from the five-year
  WMAP data by the cosmic inversion method with band-power decorrelation
  analysis

abstract:
  The primordial curvature fluctuation spectrum is reconstructed by the cosmic
inversion method using the five-year WMAP data of the cosmic microwave
background temperature anisotropy. We apply the covariance matrix analysis and
decompose the reconstructed spectrum into statistically independent
band-powers. The statistically significant deviation from a simple power-law
spectrum suggested by the analysis of the first-year data is not found in the
five-year data except possibly at one point near the border of the wavenumber
domain where accurate reconstruction is possible.


title:
Damping of the baryon acoustic oscillations in the matter power spectrum
  as a probe of the growth factor

abstract:
  We investigate the damping of the baryon acoustic oscillations (BAO)
signature in the matter power spectrum due to the quasi-nonlinear clustering of
density perturbations. On the basis of the third order perturbation theory, we
construct a fitting formula of the damping in an analytic way. This
demonstrates that the damping is closely related with the growth factor and the
amplitude of the matter power spectrum. Then, we investigate the feasibility of
constraining the growth factor through a measurement of the damping of the BAO
signature. An extension of our formula including higher order corrections of
density perturbations is also discussed.


title:
New Insights into the Quasar Type1/Type2 Dichotomy from Correlations
  between Quasar Host Orientation and Polarization

abstract:
  We investigate correlations between the direction of the optical linear
polarization and the orientation of the host galaxy/extended emission for type1
and type2 radio-loud and radio-quiet quasars. We have used high resolution
Hubble Space Telescope data and a deconvolution process to obtain a good
determination of the host galaxy/extended emission (EE) position angle. With
these new measurements and a compilation of data from the literature, we find a
significant correlation, different for type1 and type2 objects, between the
linear polarization position angle and the orientation of the EE, suggesting
scattering by an extended UV/blue region in both types of objects. Our
observations support the extension of the Unification Model to the higher
luminosity AGNs like the quasars, assuming a two component scattering model.


title: Higher radiative corrections in HQET

abstract:
  After a brief introduction to Heavy Quark Effective Theory, we discuss
$\alpha$ representation in HQET and methods of calculation of some kinds of
HQET diagrams up to three loops.


title: Hydrodynamics with conserved current from the gravity dual

abstract:
  We determine the structure of the hydrodynamics with conserved current, using
the gauge/gravity duality of charged black-hole background. It turns out that
even in the presence of the external electromagnetic field at the boundary,
bulk Einstein equation is equivalent to the boundary conservation of energy
momentum tensor and that of current. As a consequence, the thermal conductivity
and electric conductivity are calculated in terms of the parameters of the
fundamental theory. We find that Wiedermann-Franz law hold with Lorentz number
$1/e^2$


title: New arrangement of common approach to calculating the QCD ground state

abstract:
  The quark behaviour in the background of intensive stochastic gluon field is
studied. An approximate procedure for calculating the effective Hamiltonian is
developed and the corresponding ground state within the Hartree-Fock-Bogolyubov
approach is found. The comparative analysis of various model Hamiltonian is
given and transition to the chiral limit in the Keldysh model is discused in
detail.


title: Green-Kubo formula for heat conduction in open systems

abstract:
  We obtain an exact Green-Kubo type linear response result for the heat
current in an open system. The result is derived for classical Hamiltonian
systems coupled to heat baths. Both lattice models and fluid systems are
studied and several commonly used implementations of heat baths, stochastic as
well as deterministic, are considered. The results are valid in arbitrary
dimensions and for any system sizes. Our results are useful for obtaining the
linear response transport properties of mesoscopic systems. Also we point out
that for systems with anomalous heat transport, as is the case in
low-dimensional systems, the use of the standard Green-Kubo formula is
problematic and the open system formula should be used.


title:
Comment on "Absence of the Mott Glass Phase in 1D Disordered Fermionic
  Systems"

abstract:
  Comment on the paper "Absence of the Mott Glass Phase in 1D Disordered
Fermionic Systems" by T. Nattermann, A. Petkovic, Z. Ristivojevic, and F.
Schutze, Phys. Rev. Lett. 99, 186402 (2007).


title: The quantum speed up as advanced knowledge of the solution

abstract:
  With reference to a search in a database of size N, Grover states: "What is
the reason that one would expect that a quantum mechanical scheme could
accomplish the search in O(square root of N) steps? It would be insightful to
have a simple two line argument for this without having to describe the details
of the search algorithm". The answer provided in this work is: "because any
quantum algorithm takes the time taken by a classical algorithm that knows in
advance 50% of the information that specifies the solution of the problem".
This empirical fact, unnoticed so far, holds for both quadratic and exponential
speed ups and is theoretically justified in three steps: (i) once the physical
representation is extended to the production of the problem on the part of the
oracle and to the final measurement of the computer register, quantum
computation is reduction on the solution of the problem under a relation
representing problem-solution interdependence, (ii) the speed up is explained
by a simple consideration of time symmetry, it is the gain of information about
the solution due to backdating, to before running the algorithm, a
time-symmetric part of the reduction on the solution; this advanced knowledge
of the solution reduces the size of the solution space to be explored by the
algorithm, (iii) if I is the information acquired by measuring the content of
the computer register at the end of the algorithm, the quantum algorithm takes
the time taken by a classical algorithm that knows in advance 50% of I, which
brings us to the initial statement.


title: The rotation-magnetic field relation

abstract:
  Today, the generation of magnetic fields in solar-type stars and its relation
to activity and rotation can coherently be explained, although it is certainly
not understood in its entirety. Rotation facilitates the generation of magnetic
flux that couples to the stellar wind, slowing down the star. There are still
many open questions, particularly at early phases (young age), and at very low
mass. It is vexing that rotational braking becomes inefficient at the threshold
to fully convective interiors, although no threshold in magnetic activity is
seen, and the generation of large scale magnetic fields is still possible for
fully convective stars. This article briefly outlines our current understanding
of the rotation-magnetic field relation.


title: More non semigroup Lie gradings

abstract:
  This note is devoted to the construction of two very easy examples, of
respective dimensions 4 and 6, of graded Lie algebras whose grading is not
given by a semigroup, the latter one being a semisimple algebra. It is shown
that 4 is the minimal possible dimension.


title: Entanglement through conformal interfaces

abstract:
  We consider entanglement through permeable interfaces in the c=1
(1+1)-dimensional conformal field theory. We compute the partition functions
with the interfaces inserted. By the replica trick, the entanglement entropy is
obtained analytically. The entropy scales logarithmically with respect to the
size of the system, similarly to the universal scaling of the ordinary
entanglement entropy in (1+1)-dimensional conformal field theory. Its
coefficient, however, is not constant but controlled by the permeability, the
dependence on which is expressed through the dilogarithm function. The
sub-leading term of the entropy counts the winding numbers, showing an analogy
to the topological entanglement entropy which characterizes the topological
order in (2+1)-dimensional systems.


title:
Pair formation and collapse in imbalanced Fermion populations with
  unequal masses

abstract:
  We present an exact Quantum Monte Carlo study of the effect of unequal masses
on pair formation in Fermionic systems with population imbalance loaded into
optical lattices. We have considered three forms of the attractive interaction
and find in all cases that the system is unstable and collapses as the mass
difference increases and that the ground state becomes an inhomogeneous
collapsed state. We also address the question of canonical vs grand canonical
ensemble and its role, if any, in stabilizing certain phases.


title:
A 100 mW monolithic Yb waveguide laser fabricated using the femtosecond
  laser direct-write technique

abstract:
  A femtosecond laser-written monolithic waveguide laser (WGL) oscillator based
on a distributed feedback (DFB) architecture and fabricated in ytterbium doped
phosphate glass is reported. The device lased at 1033 nm with an output power
of 102 mW and a bandwidth less than 2 pm when bidirectionally pumped at 976 nm.
The WGL device was stable and operated for 50 hours without degradation. This
demonstration of a high performance WGL opens the possibility for creating a
variety of narrow-linewidth laser designs in bulk glasses.


title: Kinetics of the Bose-Einstein Condensation

abstract:
  We study the bosonic Boltzmann-Nordheim kinetic equation, which describes the
kinetic regime of weakly interacting bosons with s-wave scattering only. We
consider a spatially homogeneous fluid with an isotropic momentum distribution.
The issue of the dynamical formation of a Bose-Einstein condensate has been
studied extensively. We supply here the completed equations of motion for the
coupled system, the energy density distribution of the normal fluid and the
density of the condensate. With this information the post-nucleation
self-similar solution is investigated in more detail than before.


title:
Multi-object spectroscopy of low-redshift EIS clusters IV. Reliability
  of matched-filter results at z~0.3-0.4

abstract:
  abridged) In this paper we present new redshifts for 747 galaxies in 23 ESO
Imaging Survey (EIS) cluster fields. We use the "gap"-technique to search for
significant overdensities in redshift space for identifying groups/clusters of
galaxies. In this way we spectroscopically confirm systems in 10 of the 23
cluster candidate fields with a matched-filter estimated redshift z_MF=0.3-0.4
and with spectroscopic redshifts in the range from z=0.158 to z=0.534. We find
that the systems identified in the present paper span a broad range of
one-dimensional velocity dispersion (175-497 km/s) and richness
(12L*<=L<=65L*). Both undersampling and contamination by substructures
contribute to the uncertainty of these measurements. From the analysis of the
colours of the galaxy populations we find that ~60% of the spectroscopically
confirmed systems have a "significant" red sequence with a colour matching
passive stellar evolution models. With this paper we complete our spectroscopic
survey of the fields of 58 EIS cluster candidates with estimated redshifts
z<=0.4. We have measured a total of 1954 galaxy redshifts in the range z=0.0065
to z=0.6706. Of the 58 systems we confirm 42 (~75%) with redshifts between
z=0.095 and z=0.534.


title:
Numerical revision of the universal amplitude ratios for the
  two-dimensional 4-state Potts model

abstract:
  Monte Carlo (MC) simulations and series expansion (SE) data for the energy,
specific heat, magnetization and susceptibility of the ferromagnetic 4-state
Potts model on the square lattice are analyzed in a vicinity of the critical
point in order to estimate universal combinations of critical amplitudes. The
quality of the fits is improved using predictions of the renormalization group
(RG) approach and of conformal invariance, and restricting the data within an
appropriate temperature window.
  The RG predictions on the cancelation of the logarithmic corrections in the
universal amplitude ratios are tested. A direct calculation of the effective
ratio of the energy amplitudes using duality relations explicitly demonstrates
this cancelation of logarithms, thus supporting the predictions of RG.
  We emphasize the role of corrections of background terms on the determination
of the amplitudes. The ratios of the critical amplitudes of the
susceptibilities obtained in our analysis differ significantly from those
predicted theoretically and supported by earlier SE and MC analysis. This
disagreement might signal that the two-kink approximation used in the
analytical estimates is not sufficient to describe with fair accuracy the
amplitudes of the 4-state model.


title: Infinite rate mutually catalytic branching

abstract:
  Consider the mutually catalytic branching process with finite branching rate
$\gamma$. We show that as $\gamma\to\infty$, this process converges in
finite-dimensional distributions (in time) to a certain discontinuous process.
We give descriptions of this process in terms of its semigroup in terms of the
infinitesimal generator and as the solution of a martingale problem. We also
give a strong construction in terms of a planar Brownian motion from which we
infer a path property of the process. This is the first paper in a series or
three, wherein we also construct an interacting version of this process and
study its long-time behavior.


title: The Natural Logarithm on Time Scales

abstract:
  We define an appropriate logarithm function on time scales and present its
main properties. This gives answer to a question posed by M. Bohner in [J.
Difference Equ. Appl. {\bf 11} (2005), no. 15, 1305--1306].


title: Cosmological perturbations through the big bang

abstract:
  Several scenarios have been proposed in which primordial perturbations could
originate from quantum vacuum fluctuations in a phase corresponding to a
collapse phase (in an Einstein frame) preceding the Big Bang. I briefly review
three models which could produce scale-invariant spectra during collapse: (1)
curvature perturbations during pressureless collapse, (2) axion field
perturbations in a pre big bang scenario, and (3) tachyonic fields during
multiple-field ekpyrotic collapse. In the separate universes picture one can
derive generalised perturbation equations to describe the evolution of large
scale perturbations through a semi-classical bounce, assuming a large-scale
limit in which inhomogeneous perturbations can be described by locally
homogeneous patches. For adiabatic perturbations there exists a conserved
curvature perturbation on large scales, but isocurvature perturbations can
change the curvature perturbation through the non-adiabatic pressure
perturbation on large scales. Different models for the origin of large scale
structure lead to different observational predictions, including gravitational
waves and non-Gaussianity.


title: On the Brown--Shields conjecture for cyclicity in the Dirichlet space

abstract:
  Let $\cD$ be the Dirichlet space, namely the space of holomorphic functions
on the unit disk whose derivative is square-integrable. We establish a new
sufficient condition for a function $f\in\cD$ to be {\em cyclic}, i.e. for
$\{pf: p\text{a polynomial}\}$ to be dense in $\cD$. This allows us to prove a
special case of the conjecture of Brown and Shields that a function is cyclic
in $\cD$ iff it is outer and its zero set (defined appropriately) is of
capacity zero.


title: Topology of Manifolds with Asymptotically Nonnegative Ricci Curvature

abstract:
  In this paper, we study the topology of complete noncompact Riemannian
manifolds with asymptotically nonnegative Ricci curvature. We show that a
complete noncompact manifold with asymptoticaly nonnegative Ricci curvature and
sectional curvature decay at most quadratically is diffeomorphic to a Euclidean
n-space R^n under some conditions on the density of rays starting from the base
point p or on the volume growth of geodesic balls in M.


title: A note on smoothness and differential bases in positive characteristic

abstract:
  Let $u:A\to B$ be a morphism of noetherian local rings. We obtain smoothness
criteria for algebras with differential bases, in the case of rings containing
a field of characteristic $p>0.$ We also give smoothness criteria for reduced
morphisms.


title: Boundary non-crossings of Brownian pillow

abstract:
  Let B_0(s,t) be a Brownian pillow with continuous sample paths, and let
h,u:[0,1]^2\to R be two measurable functions. In this paper we derive upper and
lower bounds for the boundary non-crossing probability
\psi(u;h):=P{B_0(s,t)+h(s,t) \le u(s,t), \forall s,t\in [0,1]}. Further we
investigate the asymptotic behaviour of $\psi(u;\gamma h)$ with $\gamma$
tending to infinity, and solve a related minimisation problem.


title: Stable string operations are trivial

abstract:
  We show that in closed string topology and in open-closed string topology
with one $D$-brane, higher genus stable string operations are trivial. This is
a consequence of Harer's stability theorem and related stability results on the
homology of mapping class groups of surfaces with boundaries. In fact, this
vanishing result is a special case of a general result which applies to all
homological conformal field theories with a property that in the associated
topological quantum field theories, the string operations associated to genus
one cobordisms with one or two boundaries vanish. In closed string topology,
the base manifold can be either finite dimensional, or infinite dimensional
with finite dimensional cohomology for its based loop space. The above
vanishing result is based on the triviality of string operations associated to
homology classes of mapping class groups which are in the image of stabilizing
maps.


title: Cloud formation in substellar atmospheres

abstract:
  Clouds seem like an every-day experience. But -- do we know how clouds form
on brown dwarfs and extra-solar planets? How do they look like? Can we see
them? What are they composed of? Cloud formation is an old-fashioned but still
outstanding problem for the Earth atmosphere, and it has turned into a
challenge for the modelling of brown dwarf and exo-planetary atmospheres. Cloud
formation imposes strong feedbacks on the atmospheric structure, not only due
to the clouds own opacity, but also due to the depletion of the gas phase,
possibly leaving behind a dynamic and still supersaturated atmosphere. I
summarise the different approaches taken to model cloud formation in substellar
atmospheres and workout their differences. Focusing on the
phase-non-equilibrium approach to cloud formation, I demonstrate the inside we
gain from detailed micro-physical modelling on for instance the material
composition and grain size distribution inside the cloud layer on a Brown Dwarf
atmosphere. A comparison study on four different cloud approaches in Brown
Dwarf atmosphere simulations demonstrates possible uncertainties in
interpretation of observational data.


title: Monopoles and the 't Hooft tensor for generic gauge group

abstract:
  We study monopoles and corresponding 't Hooft tensor in a generic gauge
theory. This issue is relevant to the understanding of color confinement.


title: Large-scale magnetic topologies of M dwarfs

abstract:
  We present here the first results of a spectropolarimetric analysis of a
small sample (about 20) of active stars ranging from spectral type M0 to M8,
which are either fully-convective or possess a very small radiative core. This
study aims at providing new constraints on dynamo processes in fully-convective
stars.
  Results for stars with spectral types M0-M4 -- i.e. with masses above or just
below the full convection threshold (about 0.35Msun) -- are presented.
Tomographic imaging techniques allow us to reconstruct the surface magnetic
topologies from the rotationally modulated time-series of circularly polarised
profiles.
  We find strong differences between partly and fully convective stars
concerning magnetic field topology and characteristic scales, and differential
rotation. Our results suggest that magnetic field generation in fully
convective stars relies on different dynamo processes than those acting in the
Sun and other partly convective stars, in agreement with theoretical
expectations.


title:
Deep low-frequency observations with the Giant Metrewave Radio
  Telescope: a search for relic radio emission

abstract:
  We present deep multifrequency observations using the Giant Metrewave Radio
Telescope at 153, 244, 610 and 1260 MHz of a field centered on J0916+6348, to
search for evidence of fossil radio lobes which could be due to an earlier
cycle of episodic activity of the parent galaxy, as well as halos and relics in
clusters of galaxies. We do not find any unambiguous evidence of episodic
activity in a list of 374 sources, suggesting that such activity is rare even
in relatively deep low-frequency observations. We examine the spectra of all
the sources by combining our observations with those from the Westerbork
Northern Sky Survey, NRAO VLA Sky Survey and the Faint Images of the Radio Sky
at Twenty-centimeters survey. Considering only those which have measurements at
a minimum of three different frequencies, we find that almost all sources are
consistent with a straight spectrum with a median spectral index,
$\alpha\sim$0.8 (S$(\nu)\propto\nu^{-\alpha}$), which appears steeper than
theoretical expectations of the injection spectral index. We identify 14 very
steep-spectrum sources with $\alpha\geq$1.3. We examine their optical fields
and discuss the nature of some of these sources.


title: Global Electroweak Fits and the Higgs Boson Mass

abstract:
  The current electroweak data and the constraints on the Higgs mass are
discussed. Within the context of the Standard Model the data prefer a
relatively light Higgs mass.


title: Two-dimensional subwavelength focusing using a slotted meta-screen

abstract:
  A transmission screen with subwavelength slots is described which can focus
electromagnetic radiation to a two-dimensional subwavelength spot. Unlike
negative-refractive-index focusing implementations, this "meta-screen" does not
suffer from image degradation when losses are introduced and is easily scalable
from microwave to Terahertz frequencies and beyond. The slotted geometry is
designed using a theory of shifted beams to determine the necessary weighting
factors for each slot element, which are then converted to appropriate slot
dimensions. The screen was designed using a pair of rotated orthogonal focusing
axes to produce a spot on a focal plane located 0.25 \lambda away. Full-wave
simulations are corroborated by experimental measurements at 10 GHz reporting a
full-width half-maximum beam width of 0.27 \lambda along the x-axis and 0.38
\lambda along the z-axis.


title:
GW approximation with LSDA+U method and applications to NiO, MnO, and
  V$_2$O$_3$

abstract:
  A GW approximation (GWA) method named U+GWA is proposed, where we can start
GWA with more localized wave functions obtained by the local spin-density
approximation (LSDA)+U method. Then GWA and U+GWA are applied to MnO, NiO, and
V$_2$O$_3$ in antiferromagnetic phase. The band gaps and energy spectra show an
excellent agreement with the experimentally observed results and are discussed
in details. The calculated width of d-bands of V$_2$O$_3$ is much narrower than
that of the observed one which may be a mixture of t$_{2g}^2$ multiplet and
single electron t$_{2g}$ level. GWA or U+GWA does not work also in the
paramagnetic phase of V$_2$O$_3$ and the reason for thois is clarified. The
method of the unique choice of on-site Coulomb interaction is discussed in
details. The criterion for whether we should adopt GWA or U+GWA is discussed
and is assessed with the help of the off-diagonal elements of the self-energy.


title:
Sum rules for correlation functions of ionic mixtures in arbitrary
  dimension $d\geq 2$

abstract:
  The correlations in classical multi-component ionic mixtures with spatial
dimension $d\geq 2$ are studied by using a restricted grand-canonical ensemble
and the associated hierarchy equations for the correlation functions. Sum rules
for the first few moments of the two-particle correlation function are derived
and their dependence on $d$ is established. By varying $d$ continuously near
$d=2$ it is shown how the sum rules for the two-dimensional mixture are related
to those for mixtures at higher $d$.


title: Stock market volatility: An approach based on Tsallis entropy

abstract:
  One of the major issues studied in finance that has always intrigued, both
scholars and practitioners, and to which no unified theory has yet been
discovered, is the reason why prices move over time. Since there are several
well-known traditional techniques in the literature to measure stock market
volatility, a central point in this debate that constitutes the actual scope of
this paper is to compare this common approach in which we discuss such popular
techniques as the standard deviation and an innovative methodology based on
Econophysics. In our study, we use the concept of Tsallis entropy to capture
the nature of volatility. More precisely, what we want to find out is if
Tsallis entropy is able to detect volatility in stock market indexes and to
compare its values with the ones obtained from the standard deviation. Also, we
shall mention that one of the advantages of this new methodology is its ability
to capture nonlinear dynamics. For our purpose, we shall basically focus on the
behaviour of stock market indexes and consider the CAC 40, MIB 30, NIKKEI 225,
PSI 20, IBEX 35, FTSE 100 and SP 500 for a comparative analysis between the
approaches mentioned above.


title: SubRiemannian geometry on the sphere $\mathbb{S}^3$

abstract:
  The present paper starts with an introduction to quaternions and then defines
the 3-dimmensional sphere as the set of quaternions of length one. The
quaternion group induces on $\mathbb{S}^3$ a structure of noncommutative Lie
group. This group is compact and the results obtained in this case are very
different than those obtained in the case of the Heisenberg group, which is a
noncompact Lie group. Like in the Heisenberg group case, we introduce a
nonintegrable distribution on the sphere and a metric on it using two of the
noncommutative left invariant vector fields. This way $\mathbb{S}^3$ becomes a
subRiemannian manifold. It is known that the group $SU(2) $ is isomorphic with
the sphere $\mathbb{S}^3$ and represents an example of subRiemannian manifold
where the elements are matrices. The main issue here is to study the
connectivity by horizontal curves and its geodesics on this manifold. In this
paper, we are using Lagrangian method to study the connectivity theorem on
${\mathbb S}^3$ by horizontal curves with minimal arc-length. We show that for
any two points in ${\mathbb S}^3$, there exists such a geodesic joining these
two points.


title: Anomalies, Horizons and Hawking radiation

abstract:
  Hawking radiation is obtained from the Reissner-Nordstr\"{o}m blackhole with
a global monopole and the Garfinkle-Horowitz-Strominger blackhole falling in
the class of the most general spherically symmetric blackholes
$(\sqrt{-g}\neq1)$, using only chiral anomaly near the event horizon and
covariant boundary condition at the event horizon. The approach differs from
the anomaly cancellation approach since apart from the covariant boundary
condition, the chiral anomaly near the horizon is the only input to derive the
Hawking flux.


title: A diatribe on expanding space

abstract:
  Some comments are made on the usefulness or otherwise of the concept of
`expanding space' in cosmology. These notes are an expanded version of material
first published in 2001 but not previously available online except at
www.roe.ac.uk/japwww. Since that personal webpage has been referred to in
published work, it seems sensible to give these notes a more permanent home.