title: Incommensurate superfluidity of bosons in a double-well optical lattice

abstract:
  We study bosons in the first excited Bloch band of a double-well optical
lattice, recently realized at NIST. By calculating the relevant parameters from
a realistic nonseparable lattice potential, we find that in the most favorable
cases the boson lifetime in the first excited band can be several orders of
magnitude longer than the typical nearest-neighbor tunnelling timescales, in
contrast to that of a simple single-well lattice. In addition, for sufficiently
small lattice depths the excited band has minima at nonzero momenta
incommensurate with the lattice period, which opens a possibility to realize an
exotic superfluid state that spontaneously breaks the time-reversal,
rotational, and translational symmetries. We discuss possible experimental
signatures of this novel state.


title: Common Origin of (-)^L, (-)^{3B}, and Strong CP Conservation

abstract:
  The multiplicative conservation of both lepton and baryon numbers, i.e. (-)^L
and (-)^{3B}, is connected to an axionic solution of the strong CP problem in a
supersymmetric, unifiable model of quark and lepton interactions. New particles
are predicted at the TeV scale, with verifiable consequences at the Large
Hadron Collider.


title: Charge transport through weakly open one dimensional quantum wires

abstract:
  We consider resonant transmission through a finite-length quantum wire
connected to leads via finite transparency junctions. The coherent electron
transport is strongly modified by the Coulomb interaction. The low-temperature
current-voltage ($IV$) curves show step-like dependence on the bias voltage
determined by the distance between the quantum levels inside the conductor, the
pattern being dependent on the ratio between the charging energy and level
spacing. If the system is tuned close to the resonance condition by the gate
voltage, the low-voltage $IV$ curve is Ohmic. At large Coulomb energy and low
temperatures, the conductance is temperature-independent for any relationship
between temperature, level spacing, and coupling between the wire and the
leads.


title: Current driven quantum criticality in itinerant electron ferromagnets

abstract:
  We determine the effect of an in-plane current flow on the critical
properties of a 2d itinerant electron system near a ferromagnetic-paramagnetic
quantum critical point. We study a model in which a nonequilibrium steady state
is established as a result of exchange of particles and energy with an
underlying substrate. the current $\vec{j}$ gives rise not only to an effective
temperature equal to the voltage drop over a distance of order the mean free
path, but also to symmetry breaking terms of the form $\vec{j}\cdot
\vec{nabla}$ in the effective action. The effect of the symmetry breaking on
the fluctuational and critical properties is found to be small although (in
agreement with previous results) if rotational degrees of freedom are
important, the current can make the classically ordered state dynamically
unstable.


title: Narrow-Band Biphoton Generation near Atomic Resonance

abstract:
  Generating nonclassical light offers a benchmark tool for the fundamental
research and potential applications in quantum optics. Conventionally, it has
become a standard technique to produce the nonclassical light through the
nonlinear optical processes occurring in nonlinear crystals. In this review we
describe using cold atomic-gas media to generate such nonclassical light,
especially focusing on narrow-band biphoton generation. Compared with the
standard procedure, the new biphoton source has such properties as long
coherence time, long coherence length, high spectral brightness, and high
conversion efficiency. In this paper we concentrate on the theoretical aspect
of the entangled two-photon state produced from the four-wave mixing in a
multilevel atomic ensemble. We show that both linear and nonlinear optical
responses to the generated fields play an important role in determining the
biphoton waveform and, consequently on the two-photon temporal correlation.
There are two characteristic regimes determined by whether the linear or
nonlinear coherence time is dominant. In addition, our model provides a clear
physical picture that brings insight into understanding biphoton optics with
this new source. We apply our model to recent work on generating narrow-band
(and even subnatural linewidth) paired photons using the technique of
electromagnetically induced transparency and slow-light effect in cold atoms,
and find good agreements with experimental results.


title: Growth of Sobolev norms and controllability of Schr\"odinger equation

abstract:
  In this paper we obtain a stabilization result for the Schr\"odinger equation
under generic assumptions on the potential. Then we consider the Schr\"odinger
equation with a potential which has a random time-dependent amplitude. We show
that if the distribution of the amplitude is sufficiently non-degenerate, then
any trajectory of system is almost surely non-bounded in Sobolev spaces.


title: Theoretical interpretation of GRB060124: preliminary results

abstract:
  We show the preliminary results of the application of our "fireshell" model
to GRB060124. This source is very peculiar because it is the first event for
which both the prompt and the afterglow emission were observed simultaneously
by the three Swift instruments: BAT (15-350 keV), XRT (0.2-10 keV) and UVOT
(170-650 nm), due to the presence of a precursor ~ 570 s before the main burst.
We analyze GRB060124 within our "canonical" GRB scenario, identifying the
precursor with the P-GRB and the prompt emission with the afterglow peak
emission. In this way we reproduce correctly the energetics of both these two
components. We reproduce also the observed time delay between the precursor
(P-GRB) and the main burst. The effect of such a time delay in our model will
be discussed.


title: On the doubled tetrus

abstract:
  The tetrus is a sort of big brother to the tripus, W.P. Thurston's example of
a compact hyperbolic 3-manifold with totally geodesic boundary. We describe a
sixfold cover of the double of the tetrus, itself a double, which fibers over
the circle with fiber a closed surface of genus 19. We also record
arithmeticity of the doubles and certain twisted doubles of the tripus and
tetrus, and point out some consequences regarding families of covers.


title:
Charge carrier induced lattice strain and stress effects on As
  activation in Si

abstract:
  We studied lattice expansion coefficient due to As using density functional
theory with particular attention to separating the impact of electrons and
ions. Based on As deactivation mechanism under equilibrium conditions, the
effect of stress on As activation is predicted. We find that biaxial stress
results in minimal impact on As activation, which is consistent with
experimental observations by Sugii et al. [J. Appl. Phys. 96, 261 (2004)] and
Bennett et al.[J. Vac. Sci. Tech. B 26, 391 (2008)].


title: A Note on Support in Triangulated Categories

abstract:
  In this note, I define a notion of a compactly supported object in a
triangulated category. I prove a number of propositions relating this to
traditional notions of support and give an application to the theory of derived
Morita equivalence. I also discuss a connection to supersymmetric gauge
theories arising from D-branes at a singularity.


title: Gravitational Dynamics of Large Stellar Systems

abstract:
  Internal dynamical evolution can drive stellar systems into states of high
central density. For many star clusters and galactic nuclei, the time scale on
which this occurs is significantly less than the age of the universe. As a
result, such systems are expected to be sites of frequent interactions among
stars, binary systems, and stellar remnants, making them efficient factories
for the production of compact binaries, intermediate-mass black holes, and
other interesting and eminently observable astrophysical exotica. We describe
some elements of the competition among stellar dynamics, stellar evolution, and
other mechanisms to control the dynamics of stellar systems, and discuss
briefly the techniques by which these systems are modeled and studied.
Particular emphasis is placed on pathways leading to massive black holes in
present-day globular clusters and other potentially detectable sources of
gravitational radiation.


title:
Large-scale Monte Carlo simulations of the three-dimensional XY spin
  glass

abstract:
  We study the XY spin glass by large-scale Monte Carlo simulations for sizes
up to 24^3, down to temperatures below the transition temperature found in
earlier work. The data for the larger sizes show more marginal behavior than
that for the smaller sizes indicating that the lower critical dimension is
close to, and possibly equal to three. We find that the spins and chiralities
behave in a very similar manner. We also address the optimal ratio of
"over-relaxation" to "Metropolis" sweeps in the simulation.


title: Maximum likelihood estimation of a multidimensional log-concave density

abstract:
  Let X_1, ..., X_n be independent and identically distributed random vectors
with a log-concave (Lebesgue) density f. We first prove that, with probability
one, there exists a unique maximum likelihood estimator of f. The use of this
estimator is attractive because, unlike kernel density estimation, the method
is fully automatic, with no smoothing parameters to choose. Although the
existence proof is non-constructive, we are able to reformulate the issue of
computation in terms of a non-differentiable convex optimisation problem, and
thus combine techniques of computational geometry with Shor's r-algorithm to
produce a sequence that converges to the maximum likelihood estimate. For the
moderate or large sample sizes in our simulations, the maximum likelihood
estimator is shown to provide an improvement in performance compared with
kernel-based methods, even when we allow the use of a theoretical, optimal
fixed bandwidth for the kernel estimator that would not be available in
practice. We also present a real data clustering example, which shows that our
methodology can be used in conjunction with the Expectation--Maximisation (EM)
algorithm to fit finite mixtures of log-concave densities. An R version of the
algorithm is available in the package LogConcDEAD -- Log-Concave Density
Estimation in Arbitrary Dimensions.


title:
Density Fluctuations as Signature of a Non--Equilibrium First Order
  Phase Transition

abstract:
  We show that in the presence of spinodal instabilities which develop at a
first order phase transition, the fluctuations of conserved charges can be as
strong as those at the critical end point (CEP). In particular, the net baryon
number susceptibility diverges as the system crosses the isothermal spinodal
lines. This indicates that charge density fluctuations can be used not only to
probe the CEP but also the non--equilibrium first order chiral phase transition
in heavy ion collisions.


title: On Gravitational Motions

abstract:
  A new proof of the geodesic character of all motions of bodies that interact
only gravitationally - and a detailed illustration of the real meaning of the
linearized approximation of general relativity.


title:
Higgs boson decay into bottom quarks and uncertainties of perturbative
  QCD predictions

abstract:
  Different methods for treating the results of higher-order perturbative QCD
calculations of the decay width of the Standard Model Higgs boson into bottom
quarks are discusssed. Special attention is paid to the analysis of the $M_H$
dependence of the decay width $\Gamma(H\to \bar{b}b})$ in the cases when the
mass of b-quark is defined as the running parameter in the $\bar{MS}$-scheme
and as the quark pole mass. The relation between running and pole masses is
taken into account in the order $\alpha_s^4$-approximation. Some special
features of applications of Analytical Perturbation Theory (APT) are commented.


title:
Dielectron Production in C+C Collisions at 1 GeV/u and the Solution to
  the DLS Puzzle

abstract:
  The production of e+e- pairs in C+C collisions at 1 GeV/u was investigated
with the HADES experiment at GSI, Darmstadt. In the invariant-mass region $
0.15\: GeV/c^{2} \leq M_{ee} \leq 0.5\: GeV/c^{2}$ the measured pair yield
shows a strong excess above the contribution expected from hadron decays after
freeze-out. The data are in good agreement with the results of the former DLS
experiment for the same system and energy.


title: Renormalization group flow for fermionic superfluids at zero temperature

abstract:
  We present a comprehensive analysis of quantum fluctuation effects in the
superfluid ground state of an attractively interacting Fermi system, employing
the attractive Hubbard model as a prototype. The superfluid order parameter,
and fluctuations thereof, are implemented by a bosonic Hubbard-Stratonovich
field, which splits into two components corresponding to longitudinal and
transverse (Goldstone) fluctuations. Physical properties of the system are
computed from a set of approximate flow equations obtained by truncating the
exact functional renormalization group flow of the coupled fermion-boson
action. The equations capture the influence of fluctuations on non-universal
quantities such as the fermionic gap, as well as the universal infrared
asymptotics present in every fermionic superfluid. We solve the flow equations
numerically in two dimensions and compute the asymptotic behavior analytically
in two and three dimensions. The fermionic gap \Delta is reduced significantly
compared to the mean-field gap, and the bosonic order parameter \alpha, which
is equivalent to \Delta in mean-field theory, is suppressed to values below
\Delta by fluctuations. The fermion-boson vertex is only slightly renormalized.
In the infrared regime, transverse order parameter fluctuations associated with
the Goldstone mode lead to a strong renormalization of longitudinal
fluctuations: the longitudinal mass and the bosonic self-interaction vanish
linearly as a function of the scale in two dimensions, and logarithmically in
three dimensions, in agreement with the exact behavior of an interacting Bose
gas.


title: A Mechanism for Coronal Hole Jets

abstract:
  Bald patches are magnetic topologies in which the magnetic field is concave
up over part of a photospheric polarity inversion line. A bald patch topology
is believed to be the essential ingredient for filament channels and is often
found in extrapolations of the observed photospheric field. Using an analytic
source-surface model to calculate the magnetic topology of a small bipolar
region embedded in a global magnetic dipole field, we demonstrate that although
common in closed-field regions close to the solar equator, bald patches are
unlikely to occur in the open-field topology of a coronal hole. Our results
give rise to the following question: What happens to a bald patch topology when
the surrounding field lines open up? This would be the case when a bald patch
moves into a coronal hole, or when a coronal hole forms in an area that
encompasses a bald patch. Our magnetostatic models show that, in this case, the
bald patch topology almost invariably transforms into a null point topology
with a spine and a fan. We argue that the time-dependent evolution of this
scenario will be very dynamic since the change from a bald patch to null point
topology cannot occur via a simple ideal evolution in the corona. We discuss
the implications of these findings for recent Hinode XRT observations of
coronal hole jets and give an outline of planned time-dependent 3D MHD
simulations to fully assess this scenario.


title: Phase structure of a surface model with many fine holes

abstract:
  We study the phase structure of a surface model by using the canonical Monte
Carlo simulation technique on triangulated, fixed connectivity, and spherical
surfaces with many fine holes. The size of a hole is assumed to be of the order
of lattice spacing (or bond length) and hence can be negligible compared to the
surface size in the thermodynamic limit. We observe in the numerical data that
the model undergoes a first-order collapsing transition between the smooth
phase and the collapsed phase. Moreover the Hasudorff dimension H remains in
the physical bound, i.e., H<3 not only in the smooth phase but also in the
collapsed phase at the transition point. The second observation is that the
collapsing transition is accompanied by a continuous transition of surface
fluctuations. This second result distinguishes the model in this paper and the
previous one with many holes, whose size is of the order of the surface size,
because the previous surface model with large-sized holes has only the
collapsing transition and no transition of surface fluctuations.


title: High-field Current-carrying Capacity of Semiconducting Carbon Nanotubes

abstract:
  It is shown that current saturation in semiconducting carbon nanotubes is
indistinguishable from metallic nanotubes if the carrier density is above a
critical value determined by the bandgap and the LO phonon energy. This feature
stems from the higher number of current-carrying states in the semiconducting
tubes due to the van-Hove singularity at the band-edge. Above this critical
carrier density, the ensemble saturation velocity at high-fields is found to be
independent of the bandgap, but strongly dependent on the carrier density,
explaining recent observations.


title:
The evolving starburst-AGN connection: Implications for SKA and its
  pathfinders

abstract:
  How well is the modern-day starburst-AGN connection mirrored in the early
Universe? This is starting to be answered by deep wide radio surveys such as
ATLAS, which are giving us a new view of high redshift galaxies. For example,
we find powerful radio-loud AGNs which look like star-forming spirals in the
optical and infrared, a composite which is almost unknown in the modern
Universe. We find radio-bright objects which are unexpectedly invisible in the
infrared, and which may be very high redshift radio galaxies and quasars. And
although the radio-far-infrared correlation for star-forming galaxies has now
been extended down to microJy levels, we still cannot reliably distinguish
between starburst and AGN. So what do we need to do to ensure that SKA and its
pathfinders will be able to understand galaxy evolution in the early Universe?


title: Symmetry-breaking vacua and baryon condensates in AdS/CFT

abstract:
  We study the gravity duals of symmetry-breaking deformations of
superconformal field theories, AdS/CFT dual to Type IIB string theory on AdS_5
x Y where Y is a Sasaki-Einstein manifold. In these vacua both conformal
invariance and baryonic symmetries are spontaneously broken. We present a
detailed discussion of the supergravity moduli space, which involves flat form
fields on asymptotically conical Calabi-Yau manifolds, and match this to the
gauge theory vacuum moduli space. We discuss certain linearised fluctuations of
the moduli, identifying the Goldstone bosons associated with spontaneous
breaking of non-anomalous baryonic symmetries. The remaining moduli fields are
related to spontaneous breaking of anomalous baryonic symmetries. We also
elaborate on the proposal that computing condensates of baryon operators is
equivalent to computing the partition function of a non-compact Euclidean
D3-brane in the background supergravity solution, with fixed boundary
conditions at infinity.


title: Minimal Neutrino Beta Beam for Large theta_13

abstract:
  We discuss the minimum requirements for a neutrino beta beam if theta_13 is
discovered by an upcoming reactor experiment, such as Double Chooz or Daya Bay.
We require that both neutrino mass hierarchy and leptonic CP violation can be
measured to competitive precisions with a single-baseline experiment in the
entire remaining theta_13 range. We find that for very high isotope production
rates, such as they might be possible using a production ring, a (B,Li) beta
beam with a gamma as low as 60 could already be sufficient to perform all of
these measurements. If only the often used nominal source luminosities can be
achieved, for example, a (Ne,He) beta beam from Fermilab to a possibly existing
water Cherenkov detector at Homestake with gamma \sim 190-350 (depending on the
Double Chooz best-fit) could outperform practically any other beam technology
including wide-band beam and neutrino factory.


title:
Galaxy bulges and their black holes: a requirement for the quenching of
  star formation

abstract:
  One of the central features of the last 8 to 10 billion years of cosmic
history has been the emergence of a well-populated red sequence of
non-star-forming galaxies. A number of models of galaxy formation and evolution
have been devised to attempt to explain this behavior. Most current models
require feedback from supermassive black holes (AGN feedback) to quench star
formation in galaxies in the centers of their dark matter halos (central
galaxies). Such models make the strong prediction that all quenched central
galaxies must have a large supermassive black hole (and, by association, a
prominent bulge component). I show using data from the Sloan Digital Sky Survey
that the observations are consistent with this prediction. Over 99.5% of red
sequence galaxies with stellar masses in excess of 10^{10} M_{\sun} have a
prominent bulge component (as defined by having a Sersic index n above 1.5).
Those very rare red sequence central galaxies with little or no bulge (n<1.5)
usually have detectable star formation or AGN activity; the fraction of truly
quenched bulgeless central galaxies is <0.1% of the total red sequence
population. I conclude that a bulge, and by implication a supermassive black
hole, is an absolute requirement for full quenching of star formation in
central galaxies. This is in agreement with the most basic prediction of the
AGN feedback paradigm.


title: Models of the Cosmic Horseshoe Gravitational Lens

abstract:
  We model the extremely massive and luminous lens galaxy in the Cosmic
Horseshoe Einstein ring system, recently discovered in the Sloan Digital Sky
Survey. We use the semi-linear method of Warren & Dye (2003), which pixelises
the source surface brightness distribution, to invert the Einstein ring for
sets of parameterised lens models. Here, the method is refined by exploiting
Bayesian inference to optimise adaptive pixelisation of the source plane and to
choose between three differently parameterised models: a singular isothermal
ellipsoid, a power law model and a NFW profile. The most probable lens model is
the power law with a volume mass density that scales as r^(-1.96+/-0.02) and an
axis ratio of ~0.8. The mass within the Einstein ring (i.e., within a cylinder
with projected distance of ~30 kpc from the centre of the lens galaxy) is
(5.02+/-0.09)*10^12 M_solar, and the mass-to-light ratio is ~30. Even though
the lens lies in a group of galaxies, the preferred value of the external shear
is almost zero. This makes the Cosmic Horseshoe unique amongst large separation
lenses, as almost all the deflection comes from a single, very massive galaxy
with little boost from the environment.


title: Adiabatic nonlinear probes of one-dimensional Bose gases

abstract:
  We discuss two complementary problems: adiabatic loading of one-dimensional
bosons into an optical lattice and merging two one-dimensional Bose systems.
Both problems can be mapped to the sine-Gordon model. This mapping allows us to
find power-law scalings for the number of excitations with the ramping rate in
the regime where the conventional linear response approach fails. We show that
the exponent of this power law is sensitive to the interaction strength. In
particular, the response is larger, or less adiabatic, for strongly (weakly)
interacting bosons for the loading (merging) problem. Our results illustrate
that in general the nonlinear response to slow relevant perturbations can be a
powerful tool for characterizing properties of interacting systems.


title: Ultrasoft contribution to heavy-quark pair production near threshold

abstract:
  We compute the third-order correction to the heavy-quark current correlation
function due to the emission and absorption of an ultrasoft gluon. Our result
supplies a missing contribution to top-quark pair production near threshold and
the determination of the bottom quark mass from QCD sum rules.


title: Numerical Algorithms for Finding Balanced Metrics on Vector Bundles

abstract:
  In \cite{D3}, Donaldson defines a dynamical system on the space of
Fubini-Study metrics on a polarized compact K\"ahler manifold. Sano proved that
if there exists a balanced metric for the polarization, then this dynamical
system always converges to the balanced metric (\cite{S}). In \cite{DKLR},
Douglas, et. al., conjecture that the same holds in the case of vector bundles.
In this paper, we give an affirmative answer to their conjecture.


title: Nonsupersymmetric Flux Vacua and Perturbed N=2 Systems

abstract:
  We geometrically engineer N=2 theories perturbed by a superpotential by
adding 3-form flux with support at infinity to local Calabi-Yau geometries in
type IIB. This allows us to apply the formalism of Ooguri, Ookouchi, and Park
[arXiv:0704.3613] to demonstrate that, by tuning the flux at infinity, we can
stabilize the dynamical complex structure moduli in a metastable,
supersymmetry-breaking configuration. Moreover, we argue that this setup can
arise naturally as a limit of a larger Calabi-Yau which separates into two
weakly interacting regions; the flux in one region leaks into the other, where
it appears to be supported at infinity and induces the desired superpotential.
In our endeavor to confirm this picture in cases with many 3-cycles, we also
compute the CIV-DV prepotential for arbitrary number of cuts up to fifth order
in the glueball fields.


title: Searching for mid-IR obscured AGN in the CDF-N

abstract:
  The efficiency of mid-infrared selection methods for finding obscured AGN is
investigated using data in the \chandra Deep Field North. It is shown that
samples of AGN candidates compiled on the basis of mid-infrared colours only
suffer substantial contamination from normal galaxies. X-ray stacking analysis
reveals a soft mean X-ray spectrum for these sources, consistent with
Gamma~2.1. This suggests that star-forming galaxies and not obscured AGN
dominate the stacked signal. In contrast AGN selection methods that combine
mid-infrared with optical criteria are more successful in finding heavily
obscured AGN candidates. A method similar to the one proposed by Fiore et al.
(2008) is adopted to select extremely red objects (R-[3.6]>3.7mag) with high
24micron to optical flux ratio (f_24/f_R>1000). About 80% of these sources are
not detected at X-ray wavelengths. Stacking the X-ray photons at the positions
of these sources shows a flat mean X-ray spectrum (Gamma~0.8), which suggests
Compton-thick sources, low-luminosity and moderately obscured (N_H~8e22) AGN,
or a combination of the two. The mid-infrared colours and luminosities of these
sources are consistent with ULIRGs at z~2, while HST/ACS images, available for
the optically brighter of these sources, show disturbed optical morphologies in
many of them. The evidence above suggests that this population includes systems
in the process of formation.


title: Revealing the High-Redshift Star Formation Rate with Gamma-Ray Bursts

abstract:
  While the high-z frontier of star formation rate (SFR) studies has advanced
rapidly, direct measurements beyond z ~ 4 remain difficult, as shown by
significant disagreements among different results. Gamma-ray bursts, owing to
their brightness and association with massive stars, offer hope of clarifying
this situation, provided that the GRB rate can be properly related to the SFR.
The Swift GRB data reveal an increasing evolution in the GRB rate relative to
the SFR at intermediate z; taking this into account, we use the highest-z GRB
data to make a new determination of the SFR at z = 4-7. Our results exceed the
lowest direct SFR measurements, and imply that no steep drop exists in the SFR
up to at least z ~ 6.5. We discuss the implications of our result for cosmic
reionization, the efficiency of the universe in producing stellar-mass black
holes, and ``GRB feedback'' in star-forming hosts.


title: A Mott insulator of fermionic atoms in an optical lattice

abstract:
  In a solid material strong interactions between the electrons can lead to
surprising properties. A prime example is the Mott insulator, where the
suppression of conductivity is a result of interactions and not the consequence
of a filled Bloch band. The proximity to the Mott insulating phase in fermionic
systems is the origin for many intriguing phenomena in condensed matter
physics, most notably high-temperature superconductivity. Therefore it is
highly desirable to use the novel experimental tools developed in atomic
physics to access this regime. Indeed, the Hubbard model, which encompasses the
essential physics of the Mott insulator, also applies to quantum gases trapped
in an optical lattice. However, the Mott insulating regime has so far been
reached only with a gas of bosons, lacking the rich and peculiar nature of
fermions. Here we report on the formation of a Mott insulator of a repulsively
interacting two-component Fermi gas in an optical lattice. It is signalled by
three features: a drastic suppression of doubly occupied lattice sites, a
strong reduction of the compressibility inferred from the response of double
occupancy to atom number increase, and the appearance of a gapped mode in the
excitation spectrum. Direct control of the interaction strength allows us to
compare the Mott insulating and the non-interacting regime without changing
tunnel-coupling or confinement. Our results pave the way for further studies of
the Mott insulator, including spin ordering and ultimately the question of
d-wave superfluidity.


title:
Oersted fields and current density profiles in spin-torque driven
  magnetization dynamics -- Finite element modelling of realistic geometries

abstract:
  The classical impact of electrical currents on magnetic nanostructures is
analyzed with numerical calculations of current-density distributions and
Oersted fields in typical contact geometries. For the Oersted field
calculation, a hybrid finite element / boundary element method (FEM/BEM)
technique is presented which can be applied to samples of arbitrary shape.
Based on the FEM/BEM analysis, it is argued that reliable micromagnetic
simulations on spin-tranfer-torque driven magnetization processes should
include precise calculations of the Oersted field, particularly in the case of
pillar contact geometries. Similarly, finite-element simulations demonstrate
that numerical calculations of current-density distributions are required,
e.g., in the case of magnetic strips with an indentation. Such strips are
frequently used for the design of devices based on current-driven domain-wall
motion. A dramatic increase of the current density is found at the apex of the
notch, which is expected to strongly affect the magnetization processes in such
strips.


title: On Possible Light-Torsion Mixing in Background Magnetic Field

abstract:
  The interaction of the light with propagating axial torsion fields in the
presence of an external magnetic field has been investigated. Axial torsion
fields appearing in higher derivative quantum gravity possess two states, with
spin one and zero, with different masses. The torsion field with spin-0 state
is a ghost that can be removed if its mass is infinite. We investigate the
possibility when the light mixes with the torsion fields resulting in the
effect of vacuum birefringence and dichroism. The expressions for ellipticity
and the rotation of light polarization axis depending on the coupling constant
and the external magnetic field have been obtained.


title: Which Ambient Spaces Admit Isoperimetric Inequalities for Submanifolds?

abstract:
  We give simple conditions on an ambient manifold that are necessary and
sufficient for isoperimetric inequalities (for submanifolds) to hold.


title: Effective electromagnetic theory for dielectric media

abstract:
  Light in a dielectric medium moves slower than in vacuum. The corresponding
electromagnetic field equations are then no longer invariant under ordinary
Lorentz transformations, but only under such transformations corresponding to
this reduced velocity. Based on this physical symmetry, an effective theory for
low-energy electromagnetic phenomena in dielectrics is constructed. It has none
of the problems of the old formulations of Minkowski and Abraham. Dispersion in
the optical regime and the Kerr effect arise in a natural way from higher order
interaction terms. The effective field theory is quantized by standard methods
and quantum corrections can be calculated in a systematic way. Thus it relates
many different classical and quantum optical phenomena into a unified
description.


title: On sublattice determinants in reduced bases

abstract:
  We prove several inequalities on the determinants of sublattices in
LLL-reduced bases. They generalize the inequalities on the length of the
shortest vector proven by Lenstra, Lenstra, and Lovasz, and show that
LLL-reduction finds not only a short vector, but more generally, sublattices
with small determinants. We also prove new upper bounds on the product of the
norms of the first few vectors.


title:
Conformal Relativistic Viscous Hydrodynamics: Applications to RHIC
  results at sqrt(s_NN) = 200 GeV

abstract:
  A new set of equations for relativistic viscous hydrodynamics that captures
both weak-coupling and strong-coupling physics to second order in gradients has
been developed recently. We apply this framework to bulk physics at RHIC, both
for standard (Glauber-type) as well as for Color-Glass-Condensate initial
conditions and show that the results do not depend strongly on the values for
the second-order transport coefficients. Results for multiplicity, radial flow
and elliptic flow are presented and we quote the ratio of viscosity over
entropy density for which our hydrodynamic model is consistent with
experimental data. For Color-Glass-Condensate initial conditions, early
thermalization does not seem to be required in order for hydrodynamics to
describe charged hadron elliptic flow.


title: Very Long Baseline Array astrometry of low-mass young stellar objects

abstract:
  Multi-epoch radio-interferometric observations of young stellar objects can
be used to measure their displacement over the celestial sphere with a level of
precision that currently cannot be attained at any other wavelength. In
particular, the accuracy achieved using carefully calibrated, phase-referenced
observations with the Very Long Baseline Array is better than 50
micro-arcseconds. This is sufficient to measure the trigonometric parallax and
the proper motion of any radio-emitting young star within several hundred
parsecs of the Sun with an accuracy better than a few percents. Taking
advantage of this situation, we have initiated a large project aimed mainly at
measuring the distance to the nearest regions of star-formation (Taurus,
Ophiuchus, Perseus, etc.). Here, we will present the results for several stars
in Taurus and Ophiuchus, and show that the accuracy obtained is already more
than one order of magnitude better than that of previous estimates. The proper
motion obtained from the data can also provide important information,
particularly in multiple stellar systems. To illustrate this point, we will
present the case of the famous system T Tauri, where the VLBA data provide
crucial information for the characterization of the orbital path.


title:
Exploring Early Parton Momentum Distribution with the Ridge from the
  Near-Side Jet

abstract:
  In a central nucleus-nucleus collision at high-energies, medium partons
kicked by a near-side jet acquire a momentum along the jet direction and
subsequently materialize as the observed ridge particles. They carry direct
information on the early parton momentum distribution which can be extracted by
using the ridge data for central AuAu collisions at \sqrt{s_{NN}}=200 GeV. The
extracted parton momentum distribution has a thermal-like transverse momentum
distribution but a non-Gaussian, relatively flat rapidity distribution at
mid-rapidity with sharp kinematic boundaries at large rapidities that depend on
the transverse momentum.


title: Milli-arcsecond Binaries

abstract:
  As part of an astrometric program, we have used the Very Long Baseline Array
to measure the trigonometric parallax of several young stars in the Taurus and
Ophiuchus star-forming regions with great accuracy. Additionally, we have
obtained an unprecedented sample of high-resolution (~ 1 mas) images of several
young stellar systems. These images revealed that about 70% of the stars in our
sample are very tight binary stars (with separations of a few mas). Since it is
highly unlikely that 70% of all stars are such tight binaries, we argue that
selection effects are at work.


title: Distinguishing Number of Countable Homogeneous Relational Structures

abstract:
  The distinguishing number of a graph $G$ is the smallest positive integer $r$
such that $G$ has a labeling of its vertices with $r$ labels for which there is
no non-trivial automorphism of $G$ preserving these labels. Albertson and
Collins computed the distinguishing number for various finite graphs, and
Imrich, Klav\v{z}ar and Trofimov computed the distinguishing number of some
infinite graphs, showing in particular that the Random Graph has distinguishing
number 2. We compute the distinguishing number of various other finite and
countable homogeneous structures, including undirected and directed graphs, and
posets. We show that this number is in most cases two or infinite, and besides
a few exceptions conjecture that this is so for all primitive homogeneous
countable structures.


title: The problem of the body of revolution of minimal resistance

abstract:
  Newton's problem of the body of minimal aerodynamic resistance is
traditionally stated in the class of {\it convex} axially symmetric bodies with
fixed length and width. We state and solve the minimal resistance problem in
the wider class of axially symmetric but {\it generally nonconvex} bodies. The
infimum in this problem is not attained. We construct a sequence of bodies
minimizing the resistance. This sequence approximates a convex body with smooth
front surface, while the surface of approximating bodies becomes more and more
complicated. The shape of the resulting convex body and the value of minimal
resistance are compared with the corresponding results for Newton's problem and
for the problem in the intermediate class of axisymmetric bodies satisfying the
{\it single impact} assumption \cite{CL1}. In particular, the minimal
resistance in our class is smaller than in Newton's problem; the ratio goes to
1/2 as (length)/(width of the body) $\to 0$, and to 1/4 as (length)/(width)
$\to +\infty$.


title: Effects of interfacial curvature on Rayleigh-Taylor instability

abstract:
  In this work a non-trivial effect of the interfacial curvature on the
stability of accelerated interfaces, such as liquid rims, is uncovered. The new
stability analysis, based on operator and boundary perturbation theories,
reveals and quantifies influence of the interfacial curvature on the growth
rate and on the wavenumber selection of the Rayleigh-Taylor instability. The
systematic approach developed here also provides a rigorous generalization of
the widely used \textit{ad hoc} idea, due to Layzer [Astrophys. J.
\textbf{122}, 1-12 (1955)], of approximating the potential velocity field near
the interface.


title: Quantum-inspired interferometry with chirped laser pulses

abstract:
  We introduce and implement an interferometric technique based on chirped
femtosecond laser pulses and nonlinear optics. The interference manifests as a
high-visibility (> 85%) phase-insensitive dip in the intensity of an optical
beam when the two interferometer arms are equal to within the coherence length
of the light. This signature is unique in classical interferometry, but is a
direct analogue to Hong-Ou-Mandel quantum interference. Our technique exhibits
all the metrological advantages of the quantum interferometer, but with signals
at least 10^7 times greater. In particular we demonstrate enhanced resolution,
robustness against loss, and automatic dispersion cancellation. Our
interferometer offers significant advantages over previous technologies, both
quantum and classical, in precision time delay measurements and biomedical
imaging.


title: Two Dimensional Spin-Polarized Electron Gas at the Oxide Interfaces

abstract:
  The formation of a novel spin-polarized 2D electron gas at the LaMnO$_3$
monolayer embedded in SrMnO$_3$ is predicted from the first-principles
density-functional calculations. The La (d) electrons become confined in the
direction normal to the interface in the potential well of the La layer,
serving as a positively-charged layer of electron donors. These electrons
mediate a ferromagnetic alignment of the Mn t$_{2g}$ spins near the interface
via the Anderson-Hasegawa double exchange and become, in turn, spin-polarized
due to the internal magnetic fields of the Mn moments.


title:
An Accreting Black Hole in the Nuclear Star Cluster of the Bulgeless
  Galaxy NGC 1042

abstract:
  We present spectroscopic evidence for a low-luminosity, low-excitation active
galactic nucleus (AGN) in NGC 1042, powered by an intermediate-mass black hole.
These findings are significant in that the AGN is coincident with a compact
star cluster known to reside in the nucleus, thus providing an example where
the two types of central mass concentration coexist. The existence of a central
black hole is additionally remarkable in that NGC 1042 lacks a stellar bulge.
Objects such as NGC 1042 may have an important role in testing theories for the
genesis of massive black holes in galaxy nuclei, and the extent to which they
are in symbiosis with the larger stellar host.


title:
Yukawa corrections to Higgs production associated with two bottom quarks
  at the LHC

abstract:
  We investigate the leading one-loop Yukawa corrections to the process pp-> b
anti-b H in the Standard Model. We find that the next-to-leading order
correction to the cross section is small about -4% if the Higgs mass is 120GeV.
However, the appearance of leading Landau singularity when $M_H > 2M_W$ can
lead to a large correction at the next-to-next-to-leading order level for a
Higgs mass around 160GeV.


title:
19-F NMR Investigation of Iron-pnictide Superconductor
  LaFeAsO(0.89)F(0.11)

abstract:
  We report 19-F NMR investigation of the new high temperature superconductor
LaFeAsO(0.89)F(0.11) (Tc ~ 28K). We demonstrate that low frequency spin
fluctuations exhibit pseudo gap behavior above Tc. We also deduce the London
penetration depth lambda from NMR line broadening below Tc.


title:
Simulation of Current Experiments on the Tunneling Effect of Narrow
  $\epsilon$-Near-Zero Channels

abstract:
  In this paper, we discussed the current experiments on the tunneling effect
of electromagnetic energy through narrow channels of $\epsilon$-near-zero(ENZ)
medium in the microwave range. Using the finite element method, we carried out
a full wave simulation of the two kinds of experimental configurations at
present. It was shown that the ability of the electromagnetic waves penetrating
into the ENZ medium is very necessary. The present experimental setups only
using metamaterial-filled narrow channel in the configuration of parallel plate
waveguides are unlikely to realize effective tunneling. Contrarily, the
artificial plasma medium emulated using hollow metallic waveguide can achieve
nearly perfect tunneling in a narrow channel without any transition section
around its cutoff frequency, which exceed the scope of original ENZ tunneling
theory and can be described by a simple equivalent circuit model.


title: Possible Competing Order-Induced Fermi Arcs in Cuprate Superconductors

abstract:
  We investigate the scenario of competing order (CO) induced Fermi arcs and
pseudogap in cuprate superconductors. For hole-type cuprates, both phenomena as
a function of temperature and doping level can be accounted for if the CO
vanishes at $T^{\ast}$ above the superconducting transition $T_c$ and the CO
wave-vector Q is parallel to the antinodal direction. In contrast, the absence
of these phenomena and the non-monotonic d-wave gap in electron-type cuprates
may be attributed to $T^{\ast} < T_c$ and a CO wave-vector Q parallel to the
nodal direction.


title:
Markov chain Monte Carlo searches for Galactic binaries in Mock LISA
  Data Challenge 1B data sets

abstract:
  We are developing a Bayesian approach based on Markov chain Monte Carlo
techniques to search for and extract information about white dwarf binary
systems with the Laser Interferometer Space Antenna (LISA). Here we present
results obtained by applying an initial implementation of this method to some
of the data sets released in Round 1B of the Mock LISA Data Challenges. For
Challenges 1B.1.1a and 1b the signals were recovered with parameters lying
within the 95.5% posterior probability interval and the correlation between the
true and recovered waveform is in excess of 99%. Results were not submitted for
Challenge 1B.1.1c due to some convergence problems of the algorithms, despite
this, the signal was detected in a search over a 2 mHz band.


title: Infinitely many solution for prescribed curvature problem on $S^N$

abstract:
  We consider the following prescribed scalar curvature problem on $ S^N$
(*)$$\left\{\begin{array}{l} - \Delta_{S^N} u + \frac{N(N-2)}{2} u = \tilde{K}
u^{\frac{N+2}{N-2}} {on} S^N, u >0 \end{array}\right. $$ where $ \tilde{K}$ is
positive and rotationally symmetric.
  We show that if $\tilde{K}$ has a local maximum point between the poles then
equation (*) has {\bf infinitely many non-radial positive} solutions, whose
energy can be made arbitrarily large.


title:
Infinitely many positive solutions for the nonlinear Shcrodinger
  equations in $R^N$

abstract:
  We consider the following nonlinear problem in $\R^N$ $$\label{eq} - \Delta u
+V(|y|)u=u^{p},\quad u>0 {in} \R^N, u \in H^1(\R^N) $$ where $V(r)$ is a
positive function, $1<p <\frac{N+2}{N-2}$. We show that if $V(r)$ has the
following expansion: There are constants $a>0$, $m>1$, $\theta>0$, and $V_0>0$,
such that \[ V(r)= V_0+\frac a {r^m} +O\bigl(\frac1{r^{m+\theta}}\bigr),\quad
\text{as $r\to +\infty$,} \] then \eqref{eq} has {\bf infinitely many
non-radial positive} solutions, whose energy can be made arbitrarily large.


title:
Frequentist Coverage Properties of Uncertainty Intervals for Weak
  Poisson Signals in the Presence of Background

abstract:
  We construct uncertainty intervals for weak Poisson signals in the presence
of background. We consider the case where a primary experiment yields a
realization of the signal plus background, and a second experiment yields a
realization of the background. The data acquisitions times for the
background-only experiment,T_bg, and the primary experiment,T, are selected so
that their ratio varies from 1 to 25. The expected number of background counts
in the primary experiment varies from 0.2 to 2. We construct 90 and 95 percent
confidence intervals based on a propagation-of-errors method as well as two
implementations of a Neyman procedure where acceptance regions are constructed
based on a likelihood-ratio criterion that automatically determines whether the
resulting confidence interval is one-sided or two-sided. The first Neyman
procedure (due to Feldman and Cousins) neglects uncertainty in the background.
In the other Neyman procedure, we account for uncertainty in the background
with a parametric bootstrap method. We also construct minimum length Bayesian
credibility intervals. For each method, we test for the presence of a signal
based on the value of the lower endpoint of the uncertainty interval. When
T_bg/T is 5 or more and the expected background is 2 or less, the Feldman
Cousins method outperforms the other methods considered.


title: Some Issues in a Gauge Model of Unparticles

abstract:
  We address in a recent gauge model of unparticles the issues that are
important for consistency of a gauge theory, i.e., unitarity and Ward identity
of physical amplitudes. We find that non-integrable singularities arise in
physical quantities like cross section and decay rate from gauge interactions
of unparticles. We also show that Ward identity is violated due to the lack of
a dispersion relation for charged unparticles although the Ward-Takahashi
identity for general Green functions is incorporated in the model. A previous
observation that the unparticle's (with scaling dimension d) contribution to
the gauge boson self-energy is a factor (2-d) of the particle's has been
extended to the Green function of triple gauge bosons. This (2-d) rule may be
generally true for any point Green functions of gauge bosons. This implies that
the model would be trivial even as one that mimics certain dynamical effects on
gauge bosons in which unparticles serve as an interpolating field.


title: Nematic and chiral orders for planar spins on triangular lattice

abstract:
  We propose a variant of the antiferromagnetic XY model on the triangular
lattice to study the interplay between the chiral and nematic orders in
addition to the magnetic order. The model has a significant bi-quadratic
interaction of the planar spins. When the bi-quadratic exchange energy
dominates, a large temperature window is shown to exist over which the nematic
and the chiral orders co-exist without the magnetic order, thus defining a
chiral-nematic state. The phase diagram of the model and some of its critical
properties are derived by means of the Monte Carlo simulation.


title: A Pilot Survey for the H$_2$O Southern Galactic Plane Survey (HOPS)

abstract:
  We describe observations with the Mopra radiotelescope designed to assess the
feasibility of the H$_2$O maser southern Galactic plane survey (HOPS). We
mapped two one-square-degree regions along the Galactic plane using the new 12
mm receiver and the UNSW Mopra spectrometer (MOPS). We covered the entire
spectrum between 19.5 and 27.5 GHz using this setup with the main aims of
finding out which spectral lines can be detected with a quick mapping survey.
We report on detected emission from H$_2$O masers, NH$_3$ inversion transitions
(1,1), (2,2) and (3,3), HC$_3$N (3-2), as well as several radio recombination
lines.


title:
The Zamolodchikov-Faddeev algebra for open strings attached to giant
  gravitons

abstract:
  We extend the Zamolodchikov-Faddeev algebra for the superstring sigma model
on $AdS_{5}\times S^{5}$, which was formulated by Arutyunov, Frolov and
Zamaklar, to the case of open strings attached to maximal giant gravitons,
which was recently considered by Hofman and Maldacena. We obtain boundary
$S$-matrices which satisfy the standard boundary Yang-Baxter equation.


title: Broadband Quasi-Periodic Radio and X-ray Pulsations in a Solar Flare

abstract:
  We describe microwave and hard X-ray observations of strong quasiperiodic
pulsations from the GOES X1.3 solar flare on 15 June 2003. The radio
observations were made jointly by the Owens Valley Solar Array (OVSA), the
Nobeyama Polarimeter (NoRP), and the Nobeyama Radioheliograph (NoRH). Hard
X-ray observations were made by the Ramaty High Energy Solar Spectroscopic
Imager (RHESSI). Using Fourier analysis, we study the frequency- and
energy-dependent oscillation periods, differential phase, and modulation
amplitudes of the radio and X-ray pulsations. Focusing on the more complete
radio observations, we also examine the modulation of the degree of circular
polarization and of the radio spectral index. The observed properties of the
oscillations are compared with those derived from two simple models for the
radio emission. In particular, we explicitly fit the observed modulation
amplitude data to the two competing models. The first model considers the
effects of MHD oscillations on the radio emission. The second model considers
the quasi-periodic injection of fast electrons. We demonstrate that
quasiperiodic acceleration and injection of fast electrons is the more likely
cause of the quasiperiodic oscillations observed in the radio and hard X-ray
emission, which has important implications for particle acceleration and
transport in the flaring sources.


title:
On the principal symbols of $K_{\mathbb C}$-invariant differential
  operators on Hermitian symmetric spaces

abstract:
  Let $(G,K)$ be one of the following classical irreducible Hermitian symmetric
pairs of noncompact type: $(SU(p,q), S(U(p) \times U(q))),(Sp(n,R), U(n))$, or
$(SO*(2n), U(n))$. Let $G_{\mathbb C}$ and $K_{\mathbb C}$ be complexifications
of $G$ and $K$, respectively, and let $P$ be a maximal parabolic subgroup of
$G_{\mathbb C}$ whose Levi subgroup is $K_{\mathbb C}$. Let $V$ be the
holomorphic part of the complexifiaction of the tangent space at the origin of
$G/K$. It is well known that the ring of $K_{\mathbb C}$-invariant differential
operators on $V$ has a generating system $\{\varGamma_k \}$ given in terms of
determinant or Pfaffian that plays an essential role in the Capelli identities.
Our main result of this paper is that determinant or Pfaffian of the ``moment
map'' on the holomorphic cotangent bundle of $G_{\mathbb C}/P$ provides a
generating function for the principal symbols of $\varGamma_k$'s.


title:
Energy and Time Efficient Scheduling of Tasks with Dependencies on
  Asymmetric Multiprocessors

abstract:
  In this work we study the problem of scheduling tasks with dependencies in
multiprocessor architectures where processors have different speeds. We present
the preemptive algorithm "Save-Energy" that given a schedule of tasks it post
processes it to improve the energy efficiency without any deterioration of the
makespan. In terms of time efficiency, we show that preemptive scheduling in an
asymmetric system can achieve the same or better optimal makespan than in a
symmetric system. Motivited by real multiprocessor systems, we investigate
architectures that exhibit limited asymmetry: there are two essentially
different speeds. Interestingly, this special case has not been studied in the
field of parallel computing and scheduling theory; only the general case was
studied where processors have $K$ essentially different speeds. We present the
non-preemptive algorithm ``Remnants'' that achieves almost optimal makespan. We
provide a refined analysis of a recent scheduling method. Based on this
analysis, we specialize the scheduling policy and provide an algorithm of $(3 +
o(1))$ expected approximation factor. Note that this improves the previous best
factor (6 for two speeds). We believe that our work will convince researchers
to revisit this well studied scheduling problem for these simple, yet
realistic, asymmetric multiprocessor architectures.


title: Evidence for a companion to BM Gem, a silicate carbon star

abstract:
  Balmer and Paschen continuum emission as well as Balmer series lines of P
Cygni-type profile from H_gamma through H_23 are revealed in the violet spectra
of BM Gem, a carbon star associated with an oxygen-rich circumstellar shell
(`silicate carbon star') observed with the high dispersion spectrograph (HDS)
on the Subaru telescope. The blue-shifted absorption in the Balmer lines
indicates the presence of an outflow, the line of sight velocity of which is at
least 400 km s^-1, which is the highest outflow velocity observed to date in a
carbon star. We argue that the observed unusual features in BM Gem are strong
evidence for the presence of a companion, which should form an accretion disk
that gives rise to both an ionized gas region and a high velocity, variable
outflow. The estimated luminosity of ~0.2 (0.03-0.6) L_sun for the ionized gas
can be maintained by a mass accretion rate to a dwarf companion of ~10^-8 M_sun
yr^-1, while ~10^-10 M_sun yr^-1 is sufficient for accretion to a white dwarf
companion. These accretion rates are feasible for some detached binary
configurations on the basis of the Bond-Hoyle type accretion process. We
concluded that the carbon star BM Gem is in a detached binary system with a
companion of low mass and low luminosity. However, we are unable to determine
whether this companion object is a dwarf or a white dwarf. The upper limits for
binary separation are 210 AU and 930 AU for a dwarf and a white dwarf,
respectively. We also note that the observed features of BM Gem mimic those of
Mira (omi Cet), which may suggest actual similarities in their binary
configurations and circumstellar structures.


title:
Parametric instabilities of large-amplitude parallel propagating Alfven
  waves: 2-D PIC simulation

abstract:
  We discuss the parametric instabilities of large-amplitude parallel
propagating Alfven waves using the 2-D PIC simulation code. First, we confirmed
the results in the past study [Sakai et al, 2005] that the electrons are heated
due to the modified two stream instability and that the ions are heated by the
parallel propagating ion acoustic waves. However, although the past study
argued that such parallel propagating longitudinal waves are excited by
transverse modulation of parent Alfven wave, we consider these waves are more
likely to be generated by the usual, parallel decay instability. Further, we
performed other simulation runs with different polarization of the parent
Alfven waves or the different ion thermal velocity. Numerical results suggest
that the electron heating by the modified two stream instability due to the
large amplitude Alfven waves is unimportant with most parameter sets.


title:
Uncorrectable Errors of Weight Half the Minimum Distance for Binary
  Linear Codes

abstract:
  A lower bound on the number of uncorrectable errors of weight half the
minimum distance is derived for binary linear codes satisfying some condition.
The condition is satisfied by some primitive BCH codes, extended primitive BCH
codes, Reed-Muller codes, and random linear codes. The bound asymptotically
coincides with the corresponding upper bound for Reed-Muller codes and random
linear codes. By generalizing the idea of the lower bound, a lower bound on the
number of uncorrectable errors for weights larger than half the minimum
distance is also obtained, but the generalized lower bound is weak for large
weights. The monotone error structure and its related notion larger half and
trial set, which are introduced by Helleseth, Kl{\o}ve, and Levenshtein, are
mainly used to derive the bounds.


title: Conformal Invariance and Shape-Dependent Conductance of Graphene Samples

abstract:
  For a sample of an arbitrary shape, the dependence of its conductance on the
longitudinal and Hall conductivity is identical to that of a rectangle. We use
analytic results for a conducting rectangle, combined with the semicircle model
for transport coefficients, to study properties of the monolayer and bilayer
graphene. A conductance plateau centered at the neutrality point, predicted for
square geometry, is in agreement with recent experiments. For rectangular
geometry, the conductance exhibits maxima at the densities of compressible
quantum Hall states for wide samples, and minima for narrow samples. The
positions and relative sizes of these features are different in the monolayer
and bilayer cases, indicating that the conductance can be used as a tool for
sample diagnostic.


title: Isospin mass splittings of heavy baryons in HQS

abstract:
  In this paper, the electromagnetic mass differences of heavy hadrons are
discussed, while ignoring the relevant hyperfine interactions. The effects of
one-photon exchange interaction and up-down quark mass difference are
parameterized. Two mass difference equations 2\Sigma_c^+ - (\Sigma_c^{++} +
\Sigma_c^0) = 2\Sigma_b^0 - (\Sigma_b^+ + \Sigma_b^-) and (\Xi_{cc}^+ -
\Xi_{cc}^{++}) + (\Xi_{bb}^- - \Xi_{bb}^{0}) =2(\Xi_{bc}^0 - \Xi_{bc}^{+}) for
the heavy baryons are obtained. In addition, the masses of \Sigma_b^0, \Xi_b^0,
and \Xi_{cc}^{++} are predicted based on the known experimental data.


title:
A classification of phenomena in a two double-slit experiment in terms
  of symmetries of permutations of particle labels and attributes

abstract:
  Permutations of particle labels are usually used to illustrate the
relationship between classical and quantum statistics. We use permutations of
attributes/properties of particles to express properties of waves. We express
events of the well-known two-double-slit experiment (in regimes that are
appropriate to quantum interference and classical interference) in terms of
symmetries of permutations of particle labels and attributes. We also obtain a
new system called residual interference, and suggest an experiment to detect
it.


title:
Multipartite Bell-type inequalities for arbitrary numbers of settings
  and outcomes per site

abstract:
  For a multipartite correlation experiment with an arbitrary number of
settings and any spectral type of outcomes at each site, we introduce a single
general representation incorporating in a unique manner all Bell-type
inequalities for either correlation functions or joint probabilities that have
been introduced or will be introduced in the literature. Specifying this
general representation for correlation functions, we prove that the form of any
correlation Bell-type inequality does not depend on a spectral type of observed
outcomes, in particular, on their numbers at different sites, and is determined
only by extremal values of outcomes at each site. We also specify the general
form of bounds in Bell-type inequalities on joint probabilities. Our approach
to the derivation of Bell-type inequalities is universal, concise and can be
applied to a multipartite correlation experiment with outcomes of any spectral
type, discrete or continuous. We, in particular, prove that, for an N-partite
quantum state, possibly, infinite dimensional, admitting the 2x...x2-setting
LHV description, the Mermin-Klyshko inequality holds for any two bounded
quantum observables per site, not necessarily dichotomic.


title:
Fourier-Mukai partners of a K3 surface and the cusps of its Kahler
  moduli

abstract:
  Using lattice theory, we establish a one-to-one correspondence between the
set of Fourier-Mukai partners of a projective $K3$ surface and the set of
0-dimensional standard cusps of its Kahler moduli. We also study the relation
between twisted Fourier-Mukai partners and general 0-dimensional cusps, and the
relation between Fourier-Mukai partners with elliptic fibrations and certain
1-dimensional cusps.


title:
Transparent metamaterials with a negative refractive index determined by
  spatial dispersion

abstract:
  The paper considers an opportunity for the creation of an artificial
two-component metamaterial with a negative refractive index within the radio
and optical frequency band, which possesses a spatial dispersion. It is shown
that there exists a spectral region where, under certain ratio of volume
fraction unit occupied with components, the metamaterial appears transparent
without attenuating the electromagnetic wave passing through it and possessing
a phase and group velocity of the opposite sign.


title:
The effect of screening long-range Coulomb interactions on the metallic
  behavior in two-dimensional hole systems

abstract:
  We have developed a technique utilizing a double quantum well heterostructure
that allows us to study the effect of a nearby ground-plane on the metallic
behavior in a GaAs two-dimensional hole system (2DHS) in a single sample and
measurement cool-down, thereby maintaining a constant disorder potential. In
contrast to recent measurements of the effect of ground-plane screening of the
long-range Coulomb interaction in the insulating regime, we find surprisingly
little effect on the metallic behavior when we change the distance between the
2DHS and the nearby ground-plane.


title: Matchgates and classical simulation of quantum circuits

abstract:
  Let G(A,B) denote the 2-qubit gate which acts as the 1-qubit SU(2) gates A
and B in the even and odd parity subspaces respectively, of two qubits. Using a
Clifford algebra formalism we show that arbitrary uniform families of circuits
of these gates, restricted to act only on nearest neighbour (n.n.) qubit lines,
can be classically efficiently simulated. This reproduces a result originally
proved by Valiant using his matchgate formalism, and subsequently related by
others to free fermionic physics. We further show that if the n.n. condition is
slightly relaxed, to allowing the same gates to act only on n.n. and next-n.n.
qubit lines, then the resulting circuits can efficiently perform universal
quantum computation. From this point of view, the gap between efficient
classical and quantum computational power is bridged by a very modest use of a
seemingly innocuous resource (qubit swapping). We also extend the simulation
result above in various ways. In particular, by exploiting properties of
Clifford operations in conjunction with the Jordan-Wigner representation of a
Clifford algebra, we show how one may generalise the simulation result above to
provide further classes of classically efficiently simulatable quantum
circuits, which we call Gaussian quantum circuits.


title:
Non-universal scalar masses: a signal-based analysis for the Large
  Hadron Collider

abstract:
  We study the possible signatures of non-universal scalar masses in
supersymmetry at the Large Hadron Collider (LHC). This is done, following our
recent study on gaugino non-universality, via a multichannel analysis, based
largely on the ratios of event rates for different final states, aimed at
minimizing irregularity in the pattern due to extraneous effects and errors. We
have studied (a) squark-slepton non-universality, (b) non-universality in
sfermion masses of the third family, (c) the effects of $SO(10) D$-terms in
supersymmetric Grand Unified Theories. After presenting an elaborate numerical
analysis of like- and opposite-sign dileptons, inclusive and hadronically quiet
trileptons as well as inclusive jet final states, we point out specific
features of the spectrum in each case, which can be differentiated in the above
channels from the spectrum for a minimal supergravity scenario with a universal
scalar mass at high scale. The event selection criteria, and the situations
where the signals are sizable enough for a comparatve study, are also
delineated. It is found that, with some exceptions, the trilepton channels are
likely to be especially useful for this purpose.


title:
Eigenvalue distributions and Weyl laws for semi-classical
  non-self-adjoint operators in 2 dimensions

abstract:
  In this note we compare two recent results about the distribution of
eigenvalues for semi-classical pseudodifferential operators in two dimensions.
For classes of analytic operators A. Melin and the author obtained a complex
Bohr-Sommerfeld rule, showing that the eigenvalues are situated on a distorted
lattice. On the other hand, with M. Hager we showed in any dimension that Weyl
asymptotics holds with probability close to 1 for small random perturbations of
the operator. In both cases the eigenvalues distribute to leading order
according two smooth densities and we show here that the two densities are in
general different.


title: Gravity duals for non-relativistic CFTs

abstract:
  We attempt to generalize the AdS/CFT correspondence to non-relativistic
conformal field theories which are invariant under Galilean transformations.
Such systems govern ultracold atoms at unitarity, nucleon scattering in some
channels, and more generally, a family of universality classes of quantum
critical behavior. We construct a family of metrics which realize these
symmetries as isometries. They are solutions of gravity with negative
cosmological constant coupled to pressureless dust. We discuss realizations of
the dust, which include a bulk superconductor. We develop the holographic
dictionary and compute some two-point correlators. A strange aspect of the
correspondence is that the bulk geometry has two extra noncompact dimensions.


title: Unparticles in diphoton production to NLO in QCD at the LHC

abstract:
  We compute to next-to-leading order in QCD the tensor unparticle contribution
to the diphoton production at the LHC, wherein the unparticle sector is a
consequence of (a) scale invariance but not full conformal invariance and (b)
conformal invariance. We use the semi-analytical two cutoff phase space slicing
method to handle the ${\cal O}(\alpha_s)$ corrections to the $p p \to \gamma
\gamma X$ and show that our results are insensitive to the soft and collinear
cutoffs. In order to avoid the contribution of the photons due to
fragmentation, we employ the smooth cone isolation criterion. Significance of
the QCD corrections to the diphoton events including unparticles is
highlighted.


title: Tri-bimaximal Mixing from Cascades

abstract:
  We study fermion mass matrices of the cascade form which are compatible with
the tri-bimaximal lepton mixing and generation mass hierarchy. The flat-cascade
lepton matrices imply a parameter-independent relation among the mixing angles
and mass eigenvalues. The relation has several indications that the atmospheric
neutrino mixing angle is close to maximal and the other two angles have a
correlation independently of neutrino mass eigenvalues. We also discuss
phenomenological aspects of the cascade matrices; flavor-violating rare decays
of charged leptons, thermal leptogenesis, and leptonic CP violation. Possible
dynamical origins of the cascades are illustrated based on flavor symmetry and
in higher-dimensional theory.


title:
Nonideal evolution of nonaxisymmetric, force-free magnetic fields in a
  magnetar

abstract:
  Recent numerical magnetohydrodynamic calculations by Braithwaite and
collaborators support the `fossil field' hypothesis regarding the origin of
magnetic fields in compact stars and suggest that the resistive evolution of
the fossil field can explain the reorganisation and decay of magnetar magnetic
fields. Here, these findings are modelled analytically by allowing the stellar
magnetic field to relax through a quasistatic sequence of nonaxisymmetric,
force-free states, by analogy with spheromak relaxation experiments, starting
from a random field. Under the hypothesis that the force-free modes approach
energy equipartition in the absence of resistivity, the output of the numerical
calculations is semiquantitatively recovered: the field settles down to a
linked poloidal-toroidal configuration, which inflates and becomes more
toroidal as time passes. A qualitatively similar (but not identical) end state
is reached if the magnetic field evolves by exchanging helicity between small
and large scales according to an $\alpha$-dynamo-like, mean-field mechanism,
arising from the fluctuating electromotive force produced by the initial random
field. The impossibility of matching a force-free internal field to a potential
exterior field is discussed in the magnetar context.


title:
The fluorine abundance in a Galactic Bulge AGB star measured from CRIRES
  spectra

abstract:
  We present measurements of the fluorine abundance in a Galactic Bulge
Asymptotic Giant Branch (AGB) star. The measurements were performed using high
resolution K-band spectra obtained with the CRIRES spectrograph, which has been
recently installed at ESO's VLT, together with state-of-the-art model
atmospheres and synthetic spectra. This represents the first fluorine abundance
measurement in a Galactic Bulge star, and one of few measurements of this kind
in a third dredge-up oxygen-rich AGB star. The F abundance is found to be close
to the solar value scaled down to the metallicity of the star, and in agreement
with Disk giants that are comparable to the Bulge giant studied here. The
measurement is of astrophysical interest also because the star's mass can be
estimated rather accurately ($1.4 \lesssim M/\mathrm{M}_{\sun} \lesssim 2.0$).
AGB nucleosynthesis models predict only a very mild enrichment of F in such low
mass AGB stars. Thus, we suggest that the fluorine abundance found in the
studied star is representative for the star's natal cloud, and that fluorine
must have been produced at a similar level in the Bulge and in the Disk.


title: Symmetry and Asymmetry in "born again" Planetary Nebulae

abstract:
  While in the past spheroidicity was assumed, and still is used in modeling of
most nebulae, we know now that only a small number of planetary nebulae (PNe)
are really spherical or at least nearly round. Round planetary nebulae are the
minority of objects. In case of those objects that underwent a very late helium
flash (called VLTP or "born-again" PNe) it seems to be different. The first,
hydrogen rich PN, is more or less round. The ejecta from the VLTP event is
extremely asymmetrically. Angular momentum is mostly assumed to be the main
reason for the asymmetry in PNe. Thus we have to find processes either changing
their behavior within a few hundred to a few thousands of years or change their
properties dramatically due to the variation of the abundance. They most likely
have a strong link or dependency with the abundance of the ejecta.


title: Long-range antiferromagnetic interactions in ZnFe2O4 and CdFe2O4

abstract:
  For the first time, the Fe-Fe interactions in the geometrically frustrated
antiferromagnetic systems of zinc and cadmium ferrites are determined
quantitatively by the first-principles methods of density functional theory.
Both the generalized gradient approximation (GGA) as well as GGA plus the
onesite Coulomb interaction (GGA+U) are considered for the exchange-correlation
energy functional. The interactions up to third neighbours are found to be all
antiferromagnetic for both materials, regardless of which approximation scheme
(GGA or GGA+U) is used. Surprisingly, the thirdneighbour interactions are
estimated to be much stronger than the second-neighbour interactions and on the
same order in magnitude as the first-neighbour interactions.


title: Gibbsian and non-Gibbsian states at Eurandom

abstract:
  We review some of the work on non-Gibbsian states of the last ten years,
emphasizing the developments in which Eurandom played a role.


title:
The chemical composition of red giant stars in four intermediate-age
  clusters of the Large Magellanic Cloud

abstract:
  This paper presents the chemical abundance analysis of a sample of 27 red
giant stars located in 4 popolous intermediate-age globular clusters in the
Large Magellanic Cloud, namely NGC 1651, 1783, 1978 and 2173. This analysis is
based on high-resolution (R ~ 47000) spectra obtained with the UVES@VLT
spectrograph. For each cluster we derived up to 20 abundance ratios sampling
the main chemical elemental groups, namely light odd-Z, alpha, iron-peak and
neutron-capture elements. All the analysed abundance patterns behave similarly
in the 4 clusters and also show negligible star-to-star scatter within each
cluster. We find [Fe/H]=-0.30+-0.03, -0.35+-0.02, -0.38+-0.02 and -0.51+-0.03
dex for NGC 1651, 1783, 1978 and 2173, respectively. The measurement of light
odd-Z nuclei gives slightly subsolar [Na/Fe] and a more significant [Al/Fe]
depletion (~ -0.50 dex). The [alpha / Fe] abundance ratios are nearly solar,
while the iron-peak elements well trace that one of the iron. s-process
elements behave in a peculiar way: light s-elements give subsolar [Y/Fe] and
[Zr/Fe] abundance ratios, while heavy s-elements give enhanced [Ba/Fe], [La/Fe]
and [Nd/Fe] with respect to the solar values. Also, the [Eu/Fe] abundance ratio
turns out to be enhanced (~ 0.4 dex).


title:
On the exceptional locus of the birational projections of normal surface
  singularity into a plane

abstract:
  Given a normal surface singularity $(X, Q)$ and a birational morphism to a
non- singular surface $\pi : X \to S$, we investigate the local geometry of the
exceptional divisor $L$ of $\pi$. We prove that the dimension of the tangent
space to $L$ at $Q$ equals the number of exceptional components meeting at $Q$.
Consequences relative to the existence of such birational projections
contracting a prescribed number of irreducible curves are deduced. A new
characterization of minimal singularities is obtained in these terms.


title:
Dynamical symmetries of two-dimensional systems in relativistic quantum
  mechanics

abstract:
  The two-dimensional Dirac Hamiltonian with equal scalar and vector potentials
has been proved commuting with the deformed orbital angular momentum $L$. When
the potential takes the Coulomb form, the system has an SO(3) symmetry, and
similarly the harmonic oscillator potential possesses an SU(2) symmetry. The
generators of the symmetric groups are derived for these two systems
separately. The corresponding energy spectra are yielded naturally from the
Casimir operators. Their non-relativistic limits are also discussed.


title:
Structural, magnetic and electronic properties of quaternary
  oxybismuthides LaOMBi (where M = Sc, Ti ... Ni, Cu) - possible parent phases
  for new superconducting materials

abstract:
  The extensive ab initio total energy calculations using the VASP-PAW method
with the generalized gradient approximation (GGA) for the exchange-correlation
potential are applied to systematic investigation of structural, electronic and
magnetic properties in quaternary oxybismuthides LaOMBi (where M = Sc, Ti...Ni,
Cu). The energy spectrum features similar to lanthanum-iron oxyarsenide LaOFeAs
and non-magnetic ground state are indicative of superconductivity possible in
lanthanum-nickel oxybismuthide LaONiBi.


title: Geometric construction of cluster algebras and cluster categories

abstract:
  In this note we explain how to obtain cluster algebras from triangulations of
(punctured) discs following the approach of S. Fomin, M. Shapiro and D.
Thurston. Furthermore, we give a description of m-cluster categories via
diagonals (arcs) in (punctured) polygons and of m-cluster categories via powers
of translation quivers as given in joint work with R. Marsh.


title: Heterotic AdS_3/CFT_2 duality with (0,4) spacetime supersymmetry

abstract:
  We discuss the AdS_3/CFT_2 duality of a heterotic three-charge model with
(0,4) target space supersymmetry. The worldsheet theory for heterotic strings
on the AdS_3 x S^3/Z_N x T^4 near-horizon geometry was constructed by Kutasov,
Larsen and Leigh in [hep-th/9812027]. We propose that the dual conformal field
theory is given by a two-dimensional (0,4) sigma model arising on the Higgs
branch of an orbifolded ADHM model. As a non-trivial consistency check of the
correspondence, we find that the left- and right-moving central charges of the
infrared conformal field theory agree with those predicted by the worldsheet
model. Moreover, using the entropy function formalism, we show that to
next-to-leading order the central charge can also be obtained from an
alpha'-corrected supergravity theory.


title: Brans-Dicke geometry

abstract:
  We reveal the non-metric geometry underlying omega-->0 Brans-Dicke theory by
unifying the metric and scalar field into a single geometric structure. Taking
this structure seriously as the geometry to which matter universally couples,
we show that the theory is fully consistent with solar system tests. This is in
striking constrast with the standard metric coupling, which grossly violates
post-Newtonian experimental constraints.


title:
FASTLens (FAst STatistics for weak Lensing) : Fast method for Weak
  Lensing Statistics and map making

abstract:
  With increasingly large data sets, weak lensing measurements are able to
measure cosmological parameters with ever greater precision. However this
increased accuracy also places greater demands on the statistical tools used to
extract the available information. To date, the majority of lensing analyses
use the two point-statistics of the cosmic shear field. These can either be
studied directly using the two-point correlation function, or in Fourier space,
using the power spectrum. But analyzing weak lensing data inevitably involves
the masking out of regions or example to remove bright stars from the field.
Masking out the stars is common practice but the gaps in the data need proper
handling. In this paper, we show how an inpainting technique allows us to
properly fill in these gaps with only $N \log N$ operations, leading to a new
image from which we can compute straight forwardly and with a very good
accuracy both the pow er spectrum and the bispectrum. We propose then a new
method to compute the bispectrum with a polar FFT algorithm, which has the main
advantage of avoiding any interpolation in the Fourier domain. Finally we
propose a new method for dark matter mass map reconstruction from shear
observations which integrates this new inpainting concept. A range of examples
based on 3D N-body simulations illustrates the results.


title:
Morphologies of the Nebulae around "born-again" Central Stars of
  Planetary Nebulae

abstract:
  While in the past spherodicity was assumed, and still is used in modeling of
most nebulae, we know now that only a small number of planetary nebulae (PNe)
are really spherical or at least nearly round. Round planetary nebulae are the
minority of objects. In the case of those objects that underwent a very late
helium flash (called VLTP objects or ``born-again'' PNe) it seems to be
different. The first, hydrogen-rich PN, is more or less round. The ejecta from
the VLTP event, in contrast, are extremely asymmetrical.


title:
The effects of distributed life cycles on the dynamics of viral
  infections

abstract:
  We explore the role of cellular life cycles for viruses and host cells in an
infection process. For this purpose, we derive a generalized version of the
basic model of virus dynamics (Nowak, M.A., Bangham, C.R.M., 1996. Population
dynamics of immune responses to persistent viruses. Science 272, 74-79) from a
mesoscopic description. In its final form the model can be written as a set of
Volterra integrodifferential equations. We consider the role of age-distributed
delays for death times and the intracellular (eclipse) phase. These processes
are implemented by means of probability distribution functions. The basic
reproductive ratio $R_0$ of the infection is properly defined in terms of such
distributions by using an analysis of the equilibrium states and their
stability. It is concluded that the introduction of distributed delays can
strongly modify both the value of $R_0$ and the predictions for the virus
loads, so the effects on the infection dynamics are of major importance. We
also show how the model presented here can be applied to some simple situations
where direct comparison with experiments is possible. Specifically,
phage-bacteria interactions are analysed. The dynamics of the eclipse phase for
phages is characterized analytically, which allows us to compare the
performance of three different fittings proposed before for the one-step growth
curve.


title: Logic Mining Using Neural Networks

abstract:
  Knowledge could be gained from experts, specialists in the area of interest,
or it can be gained by induction from sets of data. Automatic induction of
knowledge from data sets, usually stored in large databases, is called data
mining. Data mining methods are important in the management of complex systems.
There are many technologies available to data mining practitioners, including
Artificial Neural Networks, Regression, and Decision Trees. Neural networks
have been successfully applied in wide range of supervised and unsupervised
learning applications. Neural network methods are not commonly used for data
mining tasks, because they often produce incomprehensible models, and require
long training times. One way in which the collective properties of a neural
network may be used to implement a computational task is by way of the concept
of energy minimization. The Hopfield network is well-known example of such an
approach. The Hopfield network is useful as content addressable memory or an
analog computer for solving combinatorial-type optimization problems. Wan
Abdullah [1] proposed a method of doing logic programming on a Hopfield neural
network. Optimization of logical inconsistency is carried out by the network
after the connection strengths are defined from the logic program; the network
relaxes to neural states corresponding to a valid interpretation. In this
article, we describe how Hopfield network is able to induce logical rules from
large database by using reverse analysis method: given the values of the
connections of a network, we can hope to know what logical rules are entrenched
in the database.


title:
Probing minimal supergravity in the type-I seesaw mechanism with lepton
  flavour violation at the CERN LHC

abstract:
  The most general supersymmetric seesaw mechanism has too many parameters to
be predictive and thus can not be excluded by any measurements of lepton
flavour violating (LFV) processes. We focus on the simplest version of the
type-I seesaw mechanism assuming minimal supergravity boundary conditions. We
compute branching ratios for the LFV scalar tau decays, ${\tilde \tau}_2 \to
(e,\mu) + \chi^0_1$, as well as loop-induced LFV decays at low energy, such as
$l_i \to l_j + \gamma$ and $l_i \to 3 l_j$, exploring their sensitivity to the
unknown seesaw parameters. We find some simple, extreme scenarios for the
unknown right-handed parameters, where ratios of LFV branching ratios correlate
with neutrino oscillation parameters. If the overall mass scale of the left
neutrinos and the value of the reactor angle were known, the study of LFV
allows, in principle, to extract information about the so far unknown
right-handed neutrino parameters.


title: Grainy Numbers

abstract:
  Grainy numbers are defined as tuples of bits. They form a lattice where the
meet and the join operations are an addition and a multiplication. They may be
substituted for the real numbers in the definition of fuzzy sets. The aim is to
propose an alternative negation for the complement that we'll call supplement.


title:
A phase-resolved spectroscopic study of the X-ray binary system
  4U0115+63 based on Beppo-Sax observations

abstract:
  We present a phase resolved spectral analysis of the X-ray binary 4U0115+63
based upon Beppo-Sax satellite observations. Three strong absorption lines have
been detected at all phases. We interpreted them as a cyclotron resonant
scattering. Existence of the fourth cyclotron line has been confirmed at some
phases. The cyclotron feature is found to be strongly dependent on the phase of
the source, while the continuum part of the spectrum depends on the phase
relatively weakly. The cyclotron lines turned out to be very nonequidistant.
The second line is almost always deeper then the first one. We discussed
physical conditions in the active regions of the source, under which a
cyclotron feature similar to the observed one can appear.


title: Logic Learning in Hopfield Networks

abstract:
  Synaptic weights for neurons in logic programming can be calculated either by
using Hebbian learning or by Wan Abdullah's method. In other words, Hebbian
learning for governing events corresponding to some respective program clauses
is equivalent with learning using Wan Abdullah's method for the same respective
program clauses. In this paper we will evaluate experimentally the equivalence
between these two types of learning through computer simulations.


title:
A family of series representations of the multiparameter fractional
  Brownian motion

abstract:
  We derive a family of series representations of the multiparameter fractional
Brownian motion in the centred ball of radius $R$ in the $N$-dimensional space
$\mathbb{R}^N$. Some known examples of series representations are shown to be
the members of the family under consideration.


title: Adiabatic Theorem in the Case of Continuous Spectra

abstract:
  In this paper,we present a rigorous demonstration and discussion of the
quantum adiabatic theorem for systems having a non degenerate continuous
spectrum. A new strategy is initiated by defining a kind of gap, "a virtual
gap", for the continuous spectrum through the notion of eigendifferential
(Weyl's packet) and using the differential projector operator. Finally we
obtain the validity condition of the adiabatic approximation.


title: A note on standard systems and ultrafilters

abstract:
  Let $(M,\scott X) \models \ACA$ be such that $P_\scott X$, the collection of
all unbounded sets in $\scott X$, admits a definable complete ultrafilter and
let $T$ be a theory extending first order arithmetic coded in $\scott X$ such
that $M$ thinks $T$ is consistent. We prove that there is an end-extension $N
\models T$ of $M$ such that the subsets of $M$ coded in $N$ are precisely those
in $\scott X$. As a special case we get that any Scott set with a definable
ultrafilter coding a consistent theory $T$ extending first order arithmetic is
the standard system of a recursively saturated model of $T$.


title: Spectral extrema and Lifshitz tails for non monotonous alloy type models

abstract:
  In the present note, we determine the ground state energy and study the
existence of Lifshitz tails near this energy for some non monotonous alloy type
models. Here, non monotonous means that the single site potential coming into
the alloy random potential changes sign. In particular, the random operator is
not a monotonous function of the random variables.


title: Electroweak Precision Constraints on Vector-like Fermions

abstract:
  We calculate the oblique electroweak corrections and confront with the
experiments in an extension of the Standard Model. The new fields added are a
vector-like weak doublet and a singlet fermion. After electroweak symmetry
breaking there is a mixing between the components of the new fields, but no
mixing allowed with the standard fermions. Four electroweak parameters,
$\hat{S}$, $\hat{T}$, W, Y are presented in the formalism of Barbieri et al.,
these are the generalization of the Peskin-Takeuchi S, T, U's. The vector-like
extension is slightly constrained, $\hat{T}$ requires the new neutral fermion
masses not to be very far from each other, allowing higher mass difference for
higher masses and smaller mixing. $\hat{S}, W, Y$ gives practically no
constraints on the masses. This extension can give a positive contribution to
$\hat{T} $, allowing a heavy Higgs boson in electroweak precision tests of the
Standard Model.


title: Comparison of detrending methods for fluctuation analysis

abstract:
  We examine several recently suggested methods for the detection of long-range
correlations in data series based on similar ideas as the well-established
Detrended Fluctuation Analysis (DFA). In particular, we present a detailed
comparison between the regular DFA and two recently suggested methods: the
Centered Moving Average (CMA) Method and a Modified Detrended Fluctuation
Analysis (MDFA). We find that CMA is performing equivalently as DFA in long
data with weak trends and slightly superior to DFA in short data with weak
trends. When comparing standard DFA to MDFA we observe that DFA performs
slightly better in almost all examples we studied. We also discuss how several
types of trends affect the different types of DFA. For weak trends in the data,
the new methods are comparable with DFA in these respects. However, if the
functional form of the trend in data is not a-priori known, DFA remains the
method of choice. Only a comparison of DFA results, using different detrending
polynomials, yields full recognition of the trends. A comparison with
independent methods is recommended for proving long-range correlations.


title: Generalized Geometrical Phase in the Case of Continuous Spectra

abstract:
  A quantal system in an eigenstate, of operators with a continuous
nondegenerate eigenvalue spectrum, slowly transported round a circuit C by
varing parameters in its Hamiltonian, will acquire a generalized geometrical
phase factor. An explicit formula for a generalized geometrical phase is
derived in terms of the eigenstates of the Hamiltonian. As an illustration the
generalized geometrical phase is calculated for relativistic spinning particles
in slowly-changing electromagnetic fields. It is shown that the the S-matrix
and the usual scattering (with negligible reflexion) phase shift can be
interpreted as a generalized geometrical phase.


title:
On the geometry of the $B$-connection on quasi-K\"ahler manifolds with
  Norden metric

abstract:
  The $B$-connection on almost complex manifolds with Norden metric is an
analogue of the first canonical connection of Lihnerovich in Hermitian
geometry. In the present paper it is considered a $B$-connection in the class
of the quasi-K\"ahler manifold with Norden metric. Some necessary and
sufficient conditions are derived for the corresponding curvature tensor to be
K\"ahlerian. Curvature properties for this connection are obtained. Conditions
are given for the considered manifolds to be isotropic-K\"ahler.


title:
Lie groups as 4-dimensional Riemannian or pseudo-Riemannian almost
  product manifolds with nonintegrable structure

abstract:
  A Lie group as a 4-dimensional pseudo-Riemannian manifold is considered. This
manifold is equipped with an almost product structure and a Killing metric in
two ways. In the first case Riemannian almost product manifold with
nonintegrable structure is obtained, and in the second case - a
pseudo-Riemannian one. Each belongs to a 4-parametric family of manifolds,
which are characterized geometrically.


title:
A connection with skew symmetric torsion and K\"ahler curvature tensor
  on quasi-K\"ahler manifolds with Norden metric

abstract:
  There is considered a connection with skew symmetric torsion on a
quasi-K\"ahler manifold with Norden metric. Some necessary and sufficient
conditions are derived for the corresponding curvature tensor to be
K\"ahlerian. In the case when this tensor is K\"ahlerian, some relations are
obtained between its scalar curvature and the scalar curvature of other
curvature tensors. Conditions are given for the considered manifolds to be
isotropic-K\"ahler.


title:
Atomic Structures of Graphene, Benzene and Methane with Bond Lengths as
  Sums of the Single, Double and Resonance Bond Radii of Carbon

abstract:
  Two dimensional layers of graphene are currently drawing a great attention in
fundamental and applied nanoscience. Graphene consists of interconnected
hexagons of carbon atoms as in graphite. This article presents for the first
time the structures of graphene at the atomic level and shows how it differs
from that of benzene, due to the difference in the double bond and resonance
bond based radii of carbon. The carbon atom of an aliphatic compound such as
methane has a longer covalent single bond radius as in diamond. All the atomic
structures presented here have been drawn to scale.


title:
Weiss oscillations in the magnetoconductivity of modulated graphene
  bilayer

abstract:
  We present a theoretical study of Weiss oscillations in magnetoconductivity
of bilayer graphene. Bilayer graphene in the presence of a perpendicular
magnetic field and a unidirectional weak electric modulation is considered.We
determine the $\sigma_{yy}$ component of the magnetoconductivity tensor for
this system which is shown to exhibit Weiss oscillations. We show that Weiss
oscillations in the magnetoconductivity of bilayer graphene are enhanced and
more robust with temperature compared to those in conventional two-dimensional
electron gas systems whereas they are less robust with temperature compared to
monolayer graphene. In addition, we also find phase differences of $\pi$ and
$2\pi$ in the magnetoconductivity oscillations compared to monolayer graphene
and conventional 2DEG system which arises due to the chiral nature of
quasiparticles in graphene.


title:
Causal signal transmission by quantum fields. I. Response of the
  harmonic oscillator

abstract:
  It is shown that response properties of a quantum harmonic oscillator are in
essence those of a classical oscillator, and that, paradoxical as it may be,
these classical properties underlie all quantum dynamical properties of the
system. The results are extended to non-interacting bosonic fields, both
neutral and charged.

categories: quant-ph cond-mat.stat-mech math-ph math.MP


title: Kinematics of flows on curved, deformable media

abstract:
  In this article, we first investigate the kinematics of specific geodesic
flows on two dimensional media with constant curvature, by explicitly solving
the evolution (Raychaudhuri) equations for the expansion, shear and rotation
along the flows. We point out the existence of singular (within a finite value
of the time parameter) and non-singular solutions and illustrate our results
through a `phase' diagram. This diagram demonstrates under which initial
conditions (or combinations thereof) we end up with a singularity in the
congruence and when, if at all, we encounter non--singular solutions for the
kinematic variables. Our analysis illustrates the differences which arise due
to a positive or negative value of the curvature. Subsequently, we move on to
geodesic flows on two dimensional spaces with varying curvature. As an example,
we discuss flows on a torus, where interesting oscillatory features of the
expansion, shear and rotation emerge, which are found to depend on the ratio of
the radii of the torus. The singular (within a finite time)/non--singular
nature of the solutions are also discussed. Finally, we arrive at some general
statements and point out similarities or dissimilarities that arise in
comparison to our earlier work on media in flat space.

categories: physics.class-ph gr-qc math-ph math.MP physics.gen-ph


title: An effective local routing strategy on the BA network

abstract:
  In this paper, We propose a effective routing strategy on the basis of the
so-called nearest neighbor search strategy by introducing a preferential
delivering exponent alpha. we assume that the handling capacity of one vertex
is proportional to its degree when the degree is smaller than a cut-off value
$K$, and is infinite otherwise. It is found that by tuning the parameter alpha,
the scale-free network capacity measured by the order parameter is considerably
enhanced compared to the normal nearest-neighbor strategy. Traffic dynamics
both near and far away from the critical generating rate R_c are discussed. We
also investigate R_c as functions of m (connectivity density), K (cutoff
value). Due to the low cost of acquiring nearest-neighbor information and the
strongly improved network capacity, our strategy may be useful and reasonable
for the protocol designing of modern communication networks.