title: Exploring the powering source of the TeV X-ray binary LS 5039

abstract:
  LS 5039 is one of the four TeV emitting X-ray binaries detected up to now.
The powering source of its multi-wavelength emission can be accretion in a
microquasar scenario or wind interaction in a young non-accreting pulsar
scenario. These two scenarios predict different morphologic and peak position
changes along the orbital cycle of 3.9 days, which can be tested at
milliarcsecond scales using VLBI techniques. Here we present a campaign of 5
GHz VLBA observations conducted in June 2000 (2 runs five days apart). The
results show a core component with a constant flux density, and a fast change
in the morphology and the position angle of the elongated extended emission,
but maintaining a stable flux density. These results are difficult to fit
comfortably within a microquasar scenario, whereas they appear to be compatible
with the predicted behavior for a non-accreting pulsar.


title:
Black holes and the classical model of a particle in Einstein non-linear
  electrodynamics theory

abstract:
  Modified by a logarithmic term, the non-linear electrodynamics (NED) model of
the Born-Infeld (BI) action is reconsidered. Unlike the standard BI action,
this choice provides interesting integrals of the Einstein-NED equations. It is
found that the spherical matching process for a regular black hole entails
indispensable surface stresses that vanish only for a specific value of the BI
parameter. This solution represents a classical model of an elementary particle
whose radius coincides with the horizon. In flat space time, a charged particle
becomes a conducting shell with a radius proportional to the BI parameter.


title: Some applications of the Poisson summation formula

abstract:
  We derive special forms of the Poisson summation formula for even and odd
functions, which are applied to obtain representations for Euler-type numbers
and to sum various series related to elliptic functions.


title: Spitzer observations of extended Lyman-alpha Clouds in the SSA22 field

abstract:
  We present the results of a Spitzer IRAC and MIPS 24 micron study of extended
Lyman-alpha clouds (or Lyman-alpha Blobs, LABs) within the SSA22 filamentary
structure at z = 3.09. We detect 6/26 LABs in all IRAC filters, four of which
are also detected at 24 micron, and find good correspondence with the 850
micron measurements of Geach et al. 2005. An analysis of the rest-frame
ultraviolet, optical, near- and mid-infrared colors reveals that these six
systems exhibit signs of nuclear activity (AGN)and/or extreme star formation.
Notably, they have properties that bridge galaxies dominated by star formation
(Lyman-break galaxies; LBGs) and those with AGNs (LBGs classified as QSOs). The
LAB systems not detected in all four IRAC bands, on the other hand, are, as a
group, consistent with pure star forming systems, similar to the majority of
the LBGs within the filament. These results indicate that the galaxies within
LABs do not comprise a homogeneous population, though they are also consistent
with scenarios in which the gas halos are ionized through a common mechanism
such as galaxy-scale winds driven by the galaxies within them, or gravitational
heating of the collapsing cloud itself.


title: Supersymmetric hydrodynamics from the AdS/CFT correspondence

abstract:
  We compute holographically the dispersion relation for a hydrodynamic mode of
fluctuation (the phonino) of the density of supersymmetry current in N = 4 SYM
at strong coupling. The mode appears as a pole at low frequency and momentum in
the correlator of supercurrents. It has a wave-like propagation, and we find
its speed and coefficient of attenuation.


title:
Spherically Symmetric Black Hole Formation in Painlev\'e-Gullstrand
  Coordinates

abstract:
  We perform a numerical study of black hole formation from the spherically
symmetric collapse of a massless scalar field. The calculations are done in
Painlev\'e-Gullstrand (PG) coordinates that extend across apparent horizons and
allow the numerical evolution to proceed until the onset of singularity
formation. We generate spacetime maps of the collapse and illustrate the
evolution of apparent horizons and trapping surfaces for various initial data.
We also study the critical behaviour and find the expected Choptuik scaling
with universal values for the critical exponent and echoing period consistent
with the accepted values of $\gamma=0.374$ and $\Delta = 3.44$, respectively.
The subcritical curvature scaling exhibits the expected oscillatory behaviour
but the form of the periodic oscillations in the supercritical mass scaling
relation, while universal with respect to initial PG data, is non-standard: it
is non-sinusoidal with large amplitude cusps.


title: Kinetic description of W and Z boson creation in the early universe

abstract:
  We consider an alternative mechanism for the production of the cosmic
microwave background (CMB) radiation. It is basically due to vacuum pair
creation (VPC) of vector bosons (W and Z) as a consequence of a rapid W and Z
mass generation during the electroweak phase transition in the early Universe.
The mechanism is as follows: after their pair crreation, the vector bosons may
either annihilate directly into photons or decay into leptons and quarks which
subsequently annihilate as lepton-antilepton and quark-antiquark pairs into
photons. Preliminary estimates show that the number of CMB photons obtained
this way can be sufficient to explain the presently observed CMB photon
density. In this contribution we present an exactly soluble model for vacuum
pair creation kinetics.


title:
A note on the ultracold neutrons production by neutron deceleration on
  clusters in liquid helium

abstract:
  An evaluation of slow neutrons deceleration through their interaction with
nanoclusters in liquid helium is performed. It is shown that process is
strongly suppresed if the clusters are bound by the van der Waals interaction.


title: Nonlinear Regge Trajectories in Theory and Practice

abstract:
  The problems related to nonlinear behavior of Regge trajectories (RT) and
their renormalization group invariance are discussed.


title: Controlling Multiparticle System on the Line, II - Periodic case

abstract:
  As in arXiv: math. 0809.2365 we consider classical system of interacting
particles $\mathcal{P}_1, ..., \mathcal{P}_n$ on the line with only neighboring
particles involved in interaction. On the contrast to arXiv: math. 0809.2365
now {\it periodic boundary conditions} are imposed onto the system, i.e.
$\mathcal{P}_1$ and $\mathcal{P}_n$ are considered neighboring. Periodic Toda
lattice would be a typical example. We study possibility to control periodic
multiparticle systems by means of forces applied to just few of its particles;
mainly we study system controlled by single force. The free dynamics of
multiparticle systems in periodic and nonperiodic case differ substantially. We
see that also the controlled periodic multiparticle system does not mimic its
non-periodic counterpart.
  Main result established is global controllability by means of single
controlling force of the multiparticle system with ageneric potential of
interaction. We study the nongeneric potentials for which controllability and
accessibility properties may lack. Results are formulated and proven in
Sections~2,3.


title:
Transition to complete synchronization in phase coupled oscillators with
  nearest neighbours coupling

abstract:
  We investigate synchronization in a Kuramoto-like model with nearest
neighbour coupling. Upon analyzing the behaviour of individual oscillators at
the onset of complete synchronization, we show that the time interval between
bursts in the time dependence of the frequencies of the oscillators exhibits
universal scaling and blows up at the critical coupling strength. We also bring
out a key mechanism that leads to phase locking. Finally, we deduce forms for
the phases and frequencies at the onset of complete synchronization.


title: The macroscopic qubit delusion

abstract:
  There exists a large number of experimental and theoretical results
supporting the picture of "macroscopic qubits" implemented, for instance, by
Rydberg atoms, Josephson junctions or Bose-Einstein condensates - the systems
which should rather emerge in localized semiclassical states. In this note it
is shown how, under realistic conditions, the false qubit interpretation can be
consistent with the restricted set of experimental data collected for
semiclassical systems. The recent experiments displaying semiclassical
character of Bose-Einstein condensates and possible quantumness tests for a
single system are briefly invoked also.


title:
The mass of the black hole in Centaurus A from SINFONI AO-assisted
  integral-field observations of stellar kinematics

abstract:
  We present a determination of the mass of the supermassive black hole (BH)
and the nuclear stellar orbital distribution of the elliptical galaxy Centaurus
A (NGC5128) using high-resolution integral-field observations of the stellar
kinematics. The observations were obtained with SINFONI at the ESO Very Large
Telescope in the near-infrared (K-band), using adaptive optics to correct for
the blurring effect of the earth atmosphere. The data have a spatial resolution
of 0.17" FWHM and high S/N>80 per spectral pixel so that the shape of the
stellar line-of-sight velocity-distribution can be reliably extracted. We
detect clear low-level stellar rotation, which is counter-rotating with respect
to the gas. We fit axisymmetric three-integral dynamical models to the data to
determine the best fitting values for the BH mass M_BH=(5.5+/-3.0)*10^7 Msun
(3sigma errors) and (M/L)_K=(0.65+/-0.15) in solar units. These values are in
excellent agreement with previous determinations from the gas kinematics, and
in particular with our own published values, extracted from the same data. This
provides one of the cleanest gas versus stars comparisons of BH determination,
due to the use of integral-field data for both dynamical tracers and due to a
very well resolved BH sphere of influence R_BH~0.70". We derive an accurate
profile of the orbital anisotropy and we carefully test its reliability using
spherical Jeans models with radially varying anisotropy. We find an increase in
the tangential anisotropy close to the BH, but the spatial extent of this
effect seems restricted to the size of R_BH instead of that R_b~3.9" of the
core in the surface brightness profile, contrary to detailed predictions of
current simulations of the binary BH scouring mechanism. More realistic
simulations would be required to draw conclusions from this observation.


title: Multipole surface solitons in layered thermal media

abstract:
  We address the existence and properties of multipole solitons localized at a
thermally insulating interface between uniform or layered thermal media and a
linear dielectric. We find that in the case of uniform media, only surface
multipoles with less than three poles can be stable. In contrast, we reveal
that periodic alternation of the thermo-optic coefficient in layered thermal
media makes possible the stabilization of higher order multipoles.


title:
Formation of ultracold dipolar molecules in the lowest vibrational
  levels by photoassociation

abstract:
  We recently reported the formation of ultracold LiCs molecules in the
rovibrational ground state X1Sigma+,v''=0,J''=0 [J. Deiglmayr et al., PRL 101,
133004 (2008)]. Here we discuss details of the experimental setup and present a
thorough analysis of the photoassociation step including the photoassociation
line shape. We predict the distribution of produced ground state molecules
using accurate potential nergy curves combined with an ab-initio dipole
transition moment and compare this prediction with experimental ionization
spectra. Additionally we improve the value of the dissociation energy for the
X1Sigma+ state by high resolution spectroscopy of the vibrational ground state.


title:
Superconductivity and short range order in metallic glasses
  Fe$_{x}$Ni$_{1-x}$Zr$_{2}$

abstract:
  In amorphous superconductors, superconducting and vortex pinning properties
are strongly linked to the absence of long range order. Consequently,
superconductivity and vortex phases can be studied to probe the underlying
microstructure and order of the material. This is done here from resistance and
local magnetization measurements in the superconducting state of
Fe$_{x}$Ni$_{1-x}$Zr$_{2}$ metallic glasses with $0\leq x \leq 0.6$. Firstly,
we present typical superconducting properties such as the critical temperature
and fields and their dependence on Fe content in these alloys. Then, the
observations of peculiar clockwise hysteresis loops, wide double-step
transitions and large magnetization fluctuations in glasses containing a large
amount of Fe are analyzed to reveal a change in short range order with Fe
content.


title:
Prediction of spectral shifts proportional to source distances by
  time-varying frequency or wavelength selection

abstract:
  Any frequency selective device with an ongoing drift will cause observed
spectra to be variously and simultaneously scaled in proportion to their source
distances. The reason is that detectors after the drifting selection will
integrate instantaneous electric or magnetic field values from successive
sinusoids, and these sinusoids would differ in both frequency and phase. Phase
differences between frequencies are ordinarily irrelevant, and recalibration
procedures at most correct for frequency differences. With drifting selection,
however, each integrated field value comes from *the sinusoid of the
instantaneously selected frequency at its instantaneous received phase*, hence
the waveform constructed by the integration will follow the drifting selection
with a phase acceleration given by the drift rate times the slope of the
received phase spectrum. A phase acceleration is literally a frequency shift,
and the phase spectrum slope of a received waveform is an asymptotic measure of
the source distance, as the path delay presents phase offsets proportional to
frequency times the distance, and eventually exceeding all initial phase
differences. Tunable optics may soon be fast enough for realizing such shifts
by Fourier switching, and could lead to pocket X-ray devices; sources
continuously variable from RF to gamma rays; capacity multiplication with
jamming and noise immunity in both fibre and radio channels, passive ranging
from ground to deep space; etc.


title:
Double affine Hecke algebras and bispectral quantum
  Knizhnik-Zamolodchikov equations

abstract:
  We use the double affine Hecke algebra of type GL_N to construct an explicit
consistent system of q-difference equations, which we call the bispectral
quantum Knizhnik-Zamolodchikov (BqKZ) equations. BqKZ includes, besides
Cherednik's quantum affine KZ equations associated to principal series
representations of the underlying affine Hecke algebra, a compatible system of
q-difference equations acting on the central character of the principal series
representations. We construct a meromorphic self-dual solution \Phi of BqKZ
which, upon suitable specializations of the central character, reduces to
symmetric self-dual Laurent polynomial solutions of quantum KZ equations. We
give an explicit correspondence between solutions of BqKZ and solutions of a
particular bispectral problem for the Ruijsenaars' commuting trigonometric
q-difference operators. Under this correspondence \Phi becomes a self-dual
Harish-Chandra series solution \Phi^+ of the bispectral problem. Specializing
the central character as above, we recover from \Phi^+ the symmetric self-dual
Macdonald polynomials.


title: The BMV project: Search for photon oscillations into massive particles

abstract:
  In this contribution to PSAS08 we report on the research activities developed
in our Toulouse group, in the framework of the BMV project, concerning the
search for photon oscillations into massive particles, such as axion-like
particles in the presence of a strong transverse magnetic field. We recall our
main result obtained in collaboration with LULI at \'Ecole Polytechnique
(Palaiseau, France). We also present the very preliminary results obtained with
the BMV experiment which is set up at LNCMP (Toulouse, France).


title:
Performance Expectations for a Tomography System Using Cosmic Ray Muons
  and Micro Pattern Gas Detectors for the Detection of Nuclear Contraband

abstract:
  We present results from a detailed GEANT4 simulation of a proposed Muon
Tomography System that employs compact Micro Pattern Gas Detectors with high
spatial resolution. A basic Point-Of-Closest-Approach algorithm is applied to
reconstructed muon tracks for forming 3D tomographic images of interrogated
targets. Criteria for discriminating materials by Z and discrimination power
achieved by the technique for simple scenarios are discussed for different
integration times. The simulation shows that Muon Tomography can clearly
distinguish high-Z material from low-Z and medium-Z material. We have studied
various systematic effects that affect the performance of the MT and the
discrimination power. The implications of the simulation results for the
planned development of a prototype MT station are discussed.


title: Energy Relaxation of Hot Dirac Fermions in Graphene

abstract:
  We develop a theory for the energy relaxation of hot Dirac fermions in
graphene. We obtain a generic expression for the energy relaxation rate due to
electron-phonon interaction and calculate the power loss due to both optical
and acoustic phonon emission as a function of electron temperature
$T_{\mathrm{e}}$ and density $n$. We find an intrinsic power loss weakly
dependent on carrier density and non-vanishing at the Dirac point $n = 0$,
originating from interband electron-optical phonon scattering by the intrinsic
electrons in the graphene valence band. We obtain the total power loss per
carrier $\sim 10^{-12} - 10^{-7} \mathrm{W}$ within the range of electron
temperatures $\sim 20 - 1000 \mathrm{K}$. We find optical (acoustic) phonon
emission to dominate the energy loss for $T_{\mathrm{e}} > (<) 200-300
\mathrm{K}$ in the density range $n = 10^{11}-10^{13} \mathrm{cm}^{-2}$.


title:
Survival Probability of a Local Excitation in a Non-Markovian
  Environment: Survival Collapse, Zeno and Anti-Zeno effects

abstract:
  The decay dynamics of a local excitation interacting with a non-Markovian
environment, modeled by a semi-infinite tight-binding chain, is exactly
evaluated. We identify distinctive regimes for the dynamics. Sequentially: (i)
early quadratic decay of the initial-state survival probability, up to a
spreading time $t_{S}$, (ii) exponential decay described by a self-consistent
Fermi Golden Rule, and (iii) asymptotic behavior governed by quantum diffusion
through the return processes and leading to an inverse power law decay. At this
last cross-over time $t_{R}$ a survival collapse becomes possible. This could
reduce the survival probability by several orders of magnitude. The cross-overs
times $t_{S}$ and $t_{R}$ allow to assess the range of applicability of the
Fermi Golden Rule and give the conditions for the observation of the Zeno and
Anti-Zeno effect.


title: De-Trending Time Series for Astronomical Variability Surveys

abstract:
  We present a de-trending algorithm for the removal of trends in time series.
Trends in time series could be caused by various systematic and random noise
sources such as cloud passages, changes of airmass, telescope vibration or CCD
noise. Those trends undermine the intrinsic signals of stars and should be
removed. We determine the trends from subsets of stars that are highly
correlated among themselves. These subsets are selected based on a hierarchical
tree clustering algorithm. A bottom-up merging algorithm based on the departure
from normal distribution in the correlation is developed to identify subsets,
which we call clusters. After identification of clusters, we determine a trend
per cluster by weighted sum of normalized light-curves. We then use quadratic
programming to de-trend all individual light-curves based on these determined
trends. Experimental results with synthetic light-curves containing artificial
trends and events are presented. Results from other de-trending methods are
also compared. The developed algorithm can be applied to time series for trend
removal in both narrow and wide field astronomy.


title: A numerical study of the self-similar solutions of the Schroedinger Map

abstract:
  We present a numerical study of the self-similar solutions of the Localized
Induction Approximation of a vortex filament. These self-similar solutions,
which constitute a one-parameter family, develop a singularity at finite time.
We study a number of boundary conditions that allow us reproduce the mechanism
of singularity formation. Some related questions are also considered.


title:
Adaptive Uncertainty Resolution in Bayesian Combinatorial Optimization
  Problems

abstract:
  In several applications such as databases, planning, and sensor networks,
parameters such as selectivity, load, or sensed values are known only with some
associated uncertainty. The performance of such a system (as captured by some
objective function over the parameters) is significantly improved if some of
these parameters can be probed or observed. In a resource constrained
situation, deciding which parameters to observe in order to optimize system
performance itself becomes an interesting and important optimization problem.
This general problem is the focus of this paper.
  One of the most important considerations in this framework is whether
adaptivity is required for the observations. Adaptive observations introduce
blocking or sequential operations in the system whereas non-adaptive
observations can be performed in parallel. One of the important questions in
this regard is to characterize the benefit of adaptivity for probes and
observation.
  We present general techniques for designing constant factor approximations to
the optimal observation schemes for several widely used scheduling and metric
objective functions. We show a unifying technique that relates this
optimization problem to the outlier version of the corresponding deterministic
optimization. By making this connection, our technique shows constant factor
upper bounds for the benefit of adaptivity of the observation schemes. We show
that while probing yields significant improvement in the objective function,
being adaptive about the probing is not beneficial beyond constant factors.


title: On the Past Asymptotic Dynamics of Non-minimally Coupled Dark Energy

abstract:
  We apply dynamical systems techniques to investigate cosmological models
inspired in scalar-tensor theories written in the Einstein frame. We prove that
if the potential and the coupling function are sufficiently smooth functions,
the scalar field almost always diverges into the past. The dynamics of two
important invariant sets is investigated in some detail. By assuming some
regularity conditions for the potential and for the coupling function, it is
constructed a dynamical system well suited to investigate the dynamics where
the scalar field diverges, i.e. near the initial singularity. The critical
points therein are investigated and the cosmological solutions associated to
them are characterized. We find that our system admits scaling solutions. Some
examples are taken from the bibliography to illustrate the major results. Also
we present asymptotic expansions for the cosmological solutions near the
initial space-time singularity, which extend in a way previous results of other
researchers.


title:
Adaptive Spam Detection Inspired by a Cross-Regulation Model of Immune
  Dynamics: A Study of Concept Drift

abstract:
  This paper proposes a novel solution to spam detection inspired by a model of
the adaptive immune system known as the crossregulation model. We report on the
testing of a preliminary algorithm on six e-mail corpora. We also compare our
results statically and dynamically with those obtained by the Naive Bayes
classifier and another binary classification method we developed previously for
biomedical text-mining applications. We show that the cross-regulation model is
competitive against those and thus promising as a bio-inspired algorithm for
spam detection in particular, and binary classification in general.


title: Replacing Anthropy with entropy: Does it work?

abstract:
  Probably not, because there are lots of manifestly unanthropic ways of
producing entropy. We demonstrate that the Causal Entropic Principle (CEP), as
a replacement for the anthropic principle to explain the properties of the
observed universe, suffers from many of the same problems of adopting myopic
assumptions in order to predict that various fundamental parameters take
approximately the observed values. In particular, we demonstrate that four
mechanisms -- black hole production, black hole decay, phase transitions, and
dark matter annihilations or decays -- will manifestly change the conclusions
of the CEP to predict that we should live in a universe quite different than
the one in which we find ourselves.


title: Sharp error terms for return time statistics under mixing conditions

abstract:
  We describe the statistics of repetition times of a string of symbols in a
stochastic process. Denote by T(A) the time elapsed until the process spells
the finite string A and by S(A) the number of consecutive repetitions of A. We
prove that, if the length of the string grows unbondedly, (1) the distribution
of T(A), when the process starts with A, is well aproximated by a certain
mixture of the point measure at the origin and an exponential law, and (2) S(A)
is approximately geometrically distributed. We provide sharp error terms for
each of these approximations. The errors we obtain are point-wise and allow to
get also approximations for all the moments of T(A) and S(A). To obtain (1) we
assume that the process is phi-mixing while to obtain (2) we assume the
convergence of certain contidional probabilities.


title:
Illustrating Some Implications of the Conservation Laws in Relativistic
  Mechanics

abstract:
  The conservation laws of nonrelativistic and relativistic systems are
reviewed and some simple illustrations are provided for the restrictive nature
of the relativistic conservation law involving the center of energy compared to
the nonrelativistic conservation law for the center of restmass. Extension of
the nonrelativistic interaction of particles through a potential to a system
which is Lorentz-invariant through order v^2/c^2 is found to require new
velocity- and acceleration-dependent forces which are suggestive of field
theory where the no-interaction theorem of Currie, Jordan, and Sudershan does
not hold.


title: Introducing the q-Theil index

abstract:
  Starting from the idea of Tsallis on non-extensive statistical mechanics and
the {\it q-entropy} notion, we recall the Theil index $Th$ and transform it
into the $Th_q$ index. Both indices can be used to map onto themselves any time
series in a non linear way. We develop an application of the $Th_q$ to the GDP
evolution of 20 rich countries in the time interval [1950 - 2003] and search
for a proof of globalization of their economies. First we calculate the
distances between the "new" time series and to their mean, from which such data
simple networks are constructed. We emphasize that it is useful to, and we do,
take into account different time "parameters": (i) the moving average time
window for the raw time series to calculate the $Th_q$ index; (ii) the moving
average time window for calculating the time series distances; (iii) a
correlation time lag. This allows us to deduce optimal conditions to measure
the features of the network, i.e. the appearance in 1970 of a globalization
process in the economy of such countries and the present beginning of
deviations. The $q$ value hereby used is that which measures the overall data
distribution and is equal to 1.8125.


title: A versatile and reliably re-usable ultrahigh vacuum viewport

abstract:
  We present a viewport for use in Ultra-high vacuum (UHV) based upon the
preflattened solder seal design presented in earlier work, Cox et al. Rev. Sci.
Inst. 74, 3185 (2003). The design features significant modifications to improve
long term performance. The windows have been leak tested to less than 10^-10
atm cm^3/s . From atom number measurements in an optical dipole trap loaded
from a vapor cell magneto-optical trap (MOT) inside a vacuum chamber
accommodating these viewports, we measure a trap lifetime of 9.5s suggesting a
pressure of around 10^-10 Torr limited by background Rubidium vapor pressure.
We also present a simplified design where the UHV seal is made directly to a
vacuum pipe


title:
Sensitivity of cosmic-ray experiments to ultra-high-energy photons:
  reconstruction of the spectrum and limits on the superheavy dark matter

abstract:
  We estimate the sensitivity of various experiments detecting
ultra-high-energy cosmic rays to primary photons with energies above 10^19 eV.
We demonstrate that the energy of a primary photon may be significantly (up to
a factor of ~ 10) under- or overestimated for particular primary energies and
arrival directions. We consider distortion of the reconstructed cosmic-ray
spectrum for the photonic component. As an example, we use these results to
constrain the parameter space of models of superheavy dark matter by means of
both the observed spectra and available limits on the photon content. We find
that a significant contribution of ultra-high-energy particles (photons and
protons) from decays of superheavy dark matter is allowed by all these
constraints.


title:
Search for the Lepton-Flavor Violating Decays Upsilon(3S) -> e tau and
  Upsilon(3S) -> mu tau

abstract:
  Charged lepton-flavor violating processes are extremely rare in the Standard
Model, but they may occur in several beyond-the-Standard Model theories,
including Supersymmetry or models with leptoquarks or compositeness. We present
a search for such processes in a sample of 117M Upsilon(3S) decays recorded
with the BaBar detector. We place upper limits on the branching fractions
BF(Upsilon(3S) -> e tau) < 5.0e-6 and BF(Upilon(3S) -> mu tau) < 4.1e-6 at 90%
confidence level. These results are used to place lower limits on the mass
scale of beyond-the-Standard Model physics contributing to lepton-flavor
violating decays of the Upsilon(3S).


title: FERENGI: Redshifting galaxies from SDSS to GEMS, STAGES and COSMOS

abstract:
  We describe the creation of a set of artificially "redshifted" galaxies in
the range 0.1<z<1.1 using a set of ~100 SDSS low redshift (v<7000 km/s) images
as input. The intention is to generate a training set of realistic images of
galaxies of diverse morphologies and a large range of redshifts for the GEMS
and COSMOS galaxy evolution projects. This training set allows other studies to
investigate and quantify the effects of cosmological redshift on the
determination of galaxy morphologies, distortions and other galaxy properties
that are potentially sensitive to resolution, surface brightness and bandpass
issues. We use galaxy images from the SDSS in the u, g, r, i, z filter bands as
input, and computed new galaxy images from these data, resembling the same
galaxies as located at redshifts 0.1<z<1.1 and viewed with the Hubble Space
Telescope Advanced Camera for Surveys (HST ACS). In this process we take into
account angular size change, cosmological surface brightness dimming, and
spectral change. The latter is achieved by interpolating a spectral energy
distribution that is fit to the input images on a pixel-to-pixel basis. The
output images are created for the specific HST ACS point spread function and
the filters used for GEMS (F606W and F850LP) and COSMOS (F814W). All images are
binned onto the desired pixel grids (0.03" for GEMS and 0.05" for COSMOS) and
corrected to an appropriate point spread function. Noise is added corresponding
to the data quality of the two projects and the images are added onto empty sky
pieces of real data images. We make these datasets available from our website,
as well as the code - FERENGI: "Full and Efficient Redshifting of Ensembles of
Nearby Galaxy Images" - to produce datasets for other redshifts and/or
instruments.


title: Impurity-induced frustration in correlated oxides

abstract:
  Using the example of Zn-doped La2CuO4, we demonstrate that a spinless
impurity doped into a non-frustrated antiferromagnet can induce substantial
frustrating interactions among the spins surrounding it. This counterintuitive
result is the key to resolving discrepancies between experimental data and
earlier theories. Analytic and quantum Monte Carlo studies of the
impurity-induced frustration are in a close accord with each other and
experiments. The mechanism proposed here should be common to other correlated
oxides as well.


title:
Spin-3/2 physics of semiconductor hole nanowires: Valence-band mixing
  and tunable interplay between bulk-material and orbital bound-state spin
  splittings

abstract:
  We present a detailed theoretical study of the electronic spectrum and Zeeman
splitting in hole quantum wires. The spin-3/2 character of the topmost
bulk-valence-band states results in a strong variation of subband-edge g
factors between different subbands. We elucidate the interplay between quantum
confinement and heavy-hole - light-hole mixing and identify a certain
robustness displayed by low-lying hole-wire subband edges with respect to
changes in the shape or strength of the wire potential. The ability to address
individual subband edges in, e.g., transport or optical experiments enables the
study of holes states with nonstandard spin polarization, which do not exist in
spin-1/2 systems. Changing the aspect ratio of hole wires with rectangular
cross-section turns out to strongly affect the g factor of subband edges,
providing an opportunity for versatile in-situ tuning of hole-spin properties
with possible application in spintronics. The relative importance of cubic
crystal symmetry is discussed, as well as the spin splitting away from
zone-center subband edges.


title: A Map of the Integrated Sachs-Wolfe Signal from Luminous Red Galaxies

abstract:
  We construct a map of the time derivative of the gravitational potential
traced by SDSS Luminous Red Galaxies. The potential decays on large scales due
to cosmic acceleration, leaving an imprint on cosmic microwave background (CMB)
radiation through the integrated Sachs-Wolfe (ISW) effect. With a template fit,
we directly measure this signature on the CMB at a 2-sigma confidence level.
The measurement is consistent with the cross-correlation statistic,
strengthening the claim that dark energy is indeed the cause of the
correlation. This new approach potentially simplifies the cosmological
interpretation. Our constructed linear ISW map shows no evidence for
degree-scale cold and hot spots associated with supervoid and supercluster
structures. This suggests that the linear ISW effect in a concordance
Lambda-CDM cosmology is insufficient to explain the strong CMB imprints from
these structures that we previously reported.


title:
Particle and Wave: Developing the Quantum Wave Accompanying a Classical
  Particle

abstract:
  The relationship between classical and quantum mechanics is explored in an
intuitive manner by the exercise of constructing a wave in association with a
classical particle. Using special relativity, the time coordinate in the frame
of reference of a moving particle is expressed in terms of the coordinates in
the laboratory frame of reference in order to provide an initial spatiotemporal
function to work from in initiating the development of a quantum wave. When
temporal periodicity is ascribed to the particle, a provisional spatiotemporal
function for a particle travelling at constant velocity manifests itself as an
running wave characterized by parameters associated with the moving particle. A
wave description for bidirectional motion is generated based on an average time
coordinate for a combination of oppositely directed elementary running waves,
and the resulting spatiotemporal function exhibits wave behavior characteristic
of a standing wave. Ascribing directional orientation to the intrinsic
periodicity of the particle introduces directional sub-states; variations in
the relative number of sub-states as a function of angle in combined states
lead to spatially varying magnitudes for the associated waves. Further analysis
leads to full mathematical expression for all waves representing free particle
motion. A generalization for particles subject to force fields enables us to
develop a governing differential equation identical in form to the Schroedinger
equation.


title:
Habitability of Super-Earth Planets around Other Suns: Models including
  Red Giant Branch Evolution

abstract:
  The unexpected diversity of exoplanets includes a growing number of super-
Earth planets, i.e., exoplanets with masses of up to several Earth masses and a
similar chemical and mineralogical composition as Earth. We present a thermal
evolution model for a 10 Earth mass planet orbiting a star like the Sun. Our
model is based on the integrated system approach, which describes the
photosynthetic biomass production taking into account a variety of
climatological, biogeochemical, and geodynamical processes. This allows us to
identify a so-called photosynthesis-sustaining habitable zone (pHZ) determined
by the limits of biological productivity on the planetary surface. Our model
considers the solar evolution during the main-sequence stage and along the Red
Giant Branch as described by the most recent solar model. We obtain a large set
of solutions consistent with the principal possibility of life. The highest
likelihood of habitability is found for "water worlds". Only mass-rich water
worlds are able to realize pHZ-type habitability beyond the stellar
main-sequence on the Red Giant Branch.


title: Dynamical Tides in Rotating Planets and Stars

abstract:
  Tidal dissipation may be important for the internal evolution as well as the
orbits of short-period massive planets--hot Jupiters. We revisit a mechanism
proposed by Ogilvie and Lin for tidal forcing of inertial waves, which are
short-wavelength, low-frequency disturbances restored primarily by Coriolis
rather than buoyancy forces. This mechanism is of particular interest for hot
Jupiters because it relies upon a rocky core, and because these bodies are
otherwise largely convective. Compared to waves excited at the base of the
stratified, externally heated atmosphere, waves excited at the core are more
likely to deposit heat in the convective region and thereby affect the
planetary radius. However, Ogilvie and Lin's results were numerical, and the
manner of the wave excitation was not clear. Using WKB methods, we demonstrate
the production of short waves by scattering of the equilibrium tide off the
core at critical latitudes. The tidal dissipation rate associated with these
waves scales as the fifth power of the core radius, and the implied tidal $Q$
is of order ten million for nominal values of the planet's mass, radius,
orbital period, and core size. We comment upon an alternative proposal by Wu
for exciting inertial waves in an unstratified fluid body by means of
compressibility rather than a core. We also find that even a core of rock is
unlikely to be rigid. But Ogilvie and Lin's mechanism should still operate if
the core is substantially denser than its immediate surroundings.


title:
Uncovering protein interaction in abstracts and text using a novel
  linear model and word proximity networks

abstract:
  We participated in three of the protein-protein interaction subtasks of the
Second BioCreative Challenge: classification of abstracts relevant for
protein-protein interaction (IAS), discovery of protein pairs (IPS) and text
passages characterizing protein interaction (ISS) in full text documents. We
approached the abstract classification task with a novel, lightweight linear
model inspired by spam-detection techniques, as well as an uncertainty-based
integration scheme. We also used a Support Vector Machine and the Singular
Value Decomposition on the same features for comparison purposes. Our approach
to the full text subtasks (protein pair and passage identification) includes a
feature expansion method based on word-proximity networks. Our approach to the
abstract classification task (IAS) was among the top submissions for this task
in terms of the measures of performance used in the challenge evaluation
(accuracy, F-score and AUC). We also report on a web-tool we produced using our
approach: the Protein Interaction Abstract Relevance Evaluator (PIARE). Our
approach to the full text tasks resulted in one of the highest recall rates as
well as mean reciprocal rank of correct passages. Our approach to abstract
classification shows that a simple linear model, using relatively few features,
is capable of generalizing and uncovering the conceptual nature of
protein-protein interaction from the bibliome. Since the novel approach is
based on a very lightweight linear model, it can be easily ported and applied
to similar problems. In full text problems, the expansion of word features with
word-proximity networks is shown to be useful, though the need for some
improvements is discussed.


title:
Mistuning-based Control Design to Improve Closed-Loop Stability of
  Vehicular Platoons

abstract:
  We consider a decentralized bidirectional control of a platoon of N identical
vehicles moving in a straight line. The control objective is for each vehicle
to maintain a constant velocity and inter-vehicular separation using only the
local information from itself and its two nearest neighbors. Each vehicle is
modeled as a double integrator. To aid the analysis, we use continuous
approximation to derive a partial differential equation (PDE) approximation of
the discrete platoon dynamics. The PDE model is used to explain the progressive
loss of closed-loop stability with increasing number of vehicles, and to devise
ways to combat this loss of stability.
  If every vehicle uses the same controller, we show that the least stable
closed-loop eigenvalue approaches zero as O(1/N^2) in the limit of a large
number (N) of vehicles. We then show how to ameliorate this loss of stability
by small amounts of "mistuning", i.e., changing the controller gains from their
nominal values. We prove that with arbitrary small amounts of mistuning, the
asymptotic behavior of the least stable closed loop eigenvalue can be improved
to O(1/N) All the conclusions drawn from analysis of the PDE model are
corroborated via numerical calculations of the state-space platoon model.


title: Nuclear magnetic resonance in the heavy fermion superconductors

abstract:
  Nuclear magnetic resonance has emerged as a vital technique for investigating
strongly correlated electron systems, and is particularly important for
studying superconductivity. In this paper the basic features of NMR as a
technique for probing the superconducting state are reviewed. Topics include
include spin relaxation processes, studies of vortex lattices, and phenomena
associated with unconventional pairing symmetries. Recent experimental work is
reviewed, with a particular emphasis on the heavy fermion superconductors.


title: Lipschitz Characterisation of Polytopal Hilbert Geometries

abstract:
  We prove that the Hilbert Geometry of a convex set is bi-lipschitz equivalent
to a normed vector space if and only if the convex is a polytope.


title:
A New Window of Exploration in the Mass Spectrum: Strong Lensing by
  Galaxy Groups in the SL2S

abstract:
  The existence of strong lensing systems with Einstein radii (Re) covering the
full mass spectrum, from ~1-2" (produced by galaxy scale dark matter haloes) to
>10" (produced by galaxy cluster scale haloes) have long been predicted. Many
lenses with Re around 1-2" and above 10" have been reported but very few in
between. In this article, we present a sample of 13 strong lensing systems with
Re in the range 3"- 8", i.e. systems produced by galaxy group scale dark matter
haloes, spanning a redshift range from 0.3 to 0.8. This opens a new window of
exploration in the mass spectrum, around 10^{13}- 10^{14} M_{sun}, which is a
crucial range for understanding the transition between galaxies and galaxy
clusters. Our analysis is based on multi-colour CFHTLS images complemented with
HST imaging and ground based spectroscopy. Large scale properties are derived
from both the light distribution of the elliptical galaxies group members and
weak lensing of the faint background galaxy population. On small scales, the
strong lensing analysis yields Einstein radii between 2.5" and 8". On larger
scales, the strong lenses coincide with the peak of the light distribution,
suggesting that mass is traced by light. Most of the luminosity maps have
complicated shapes, indicating that these intermediate mass structures are
dynamically young. Fitting the reduced shear with a Singular Isothermal Sphere,
we find sigma ~ 500 km/s and an upper limit of ~900 km/s for the whole sample.
The mass to light ratio for the sample is found to be M/L_i ~ 250 (solar units,
corrected for evolution), with an upper limit of 500. This can be compared to
mass to light ratios of small groups (with sigma ~ 300 km/s and galaxy clusters
with sigma > 1000 km/s, thus bridging the gap between these mass scales.


title:
Eclipse Timings of the Transient Low Mass X-ray Binary EXO0748-676. IV.
  The Rossi X-Ray Timing Explorer Eclipses

abstract:
  We report our complete database of X-ray eclipse timings of the low mass
X-ray binary EXO0748-676 observed by the Rossi X-Ray Timing Explorer (RXTE)
satellite. As of this writing we have accumulated 443 full X-ray eclipses, 392
of which have been observed with the Proportional Counter Array on RXTE. These
include both observations where an eclipse was specifically targeted and those
eclipses found in the RXTE data archive. Eclipse cycle count has been
maintained since the discovery of the EXO0748-676 system in February 1985. We
describe our observing and analysis techniques for each eclipse and describe
improvements we have made since the last compilation by Wolff et al. (2002).
The principal result of this paper is the database containing the timing
results from a seven-parameter fit to the X-ray light curve for each observed
eclipse along with the associated errors in the fitted parameters. Based on the
standard O-C analysis, EXO0748-676 has undergone four distinct orbital period
epochs since its discovery. In addition, EXO0748-676 shows small-scale events
in the O-C curve that are likely due to short-lived changes in the secondary
star.


title: Evidence of the \Theta^+ in the \gamma d \to K^+K^-pn reaction

abstract:
  The \gamma d \to K^+K^-pn reaction has been studied to search for the
evidence of the \Theta^+ by detecting K^+K^- pairs at forward angles. The
Fermi-motion corrected nK^+ invariant mass distribution shows a narrow peak at
1.524 +- 0.002 + 0.003 GeV/c^2. The statistical significance of the peak
calculated from a shape analysis is 5.1 \sigma, and the differential
cross-section for the \gamma n \to K^- \Theta^+ reaction is estimated to be 12
+- 2 nb/sr in the photon energy range from 2.0 GeV to 2.4 GeV in the LEPS
angular range by assuming the isotropic production of the \Theta^+ in the
\gamma n center-of-mass system. The obtained results support the existence of
the \Theta^+.


title: Density of isoperimetric spectra

abstract:
  We show that the set of k-dimensional isoperimetric exponents of finitely
presented groups is dense in the interval [1, \infty) for k > 1. Hence there is
no higher-dimensional analogue of Gromov's gap (1,2) in the isoperimetric
spectrum.


title: Linear theory and velocity correlations of clusters

abstract:
  Linear theory provides a reasonable description of the velocity correlations
of biased tracers both perpendicular and parallel to the line of separation,
provided one accounts for the fact that the measurement is almost always made
using pair-weighted statistics. This introduces an additional term which, for
sufficiently biased tracers, may be large. Previous work suggesting that linear
theory was grossly in error for the components parallel to the line of
separation ignored this term.


title: Gamma-Ray Burst afterglows: theory and observations

abstract:
  I discuss some theoretical expectations for the synchrotron emission from a
relativistic blast-wave interacting with the ambient medium, as a model for GRB
afterglows, and compare them with observations. An afterglow flux evolving as a
power-law in time, a bright optical flash during/after the burst, and a
light-curve break due to a tight ejecta collimation are the major predictions
that were confirmed observationally, but it should be recognized that
light-curve decay indices are not correlated with the spectral slopes (as would
be expected), optical flashes are quite rare, and jet-breaks harder to find in
Swift X-ray afterglows.
  The slowing of the early optical flux decay rate is accompanied by a spectral
evolution, indicating that the emission from ejecta (energized by the reverse
shock) is dominant in the optical over that from the forward shock (which
energizes the ambient medium) only up to 1 ks. However, a long-lived reverse
shock is required to account for the slow radio flux decays observed in many
afterglows after ~10 day.
  X-ray light-curve plateaus could be due to variations in the average
energy-per-solid-angle of the blast-wave, confirming to two other anticipated
features of GRB outflows: energy injection and angular structure. The latter is
also the more likely origin of the fast-rises seen in some optical
light-curves. To account for the existence of both chromatic and achromatic
afterglow light-curve breaks, the overall picture must be even more complex and
include a new mechanism that dominates occasionally the emission from the
blast-wave: either late internal shocks or scattering (bulk and/or
inverse-Compton) of the blast-wave emission by an outflow interior to it.


title:
On the holomorphic point of view in the theory of quantum knot
  invariants

abstract:
  In this paper we describe progress made toward the construction of the
Witten-Reshetikhin-Turaev theory of knot invariants from the geometric point of
view. This is done in the perspective of a joint result of the author with A.
Uribe which relates the quantum group and the Weyl quantizations of the moduli
space of flat SU(2)-connections on the tours. Two results are emphasized: the
reconstruction from Weyl quantization of the restriction to the torus of the
modular functor, and a description of a basis of the space of quantum
observables on the torus in terms of colored curves, which answers a question
related to quantum computing.


title:
Defect Induced Photoluminescence from Dark Excitonic States in
  Individual Single-Walled Carbon Nanotubes

abstract:
  We show that new low-energy photoluminescence (PL) bands can be created in
semiconducting single-walled carbon nanotubes by intense pulsed excitation. The
new bands are attributed to PL from different nominally dark excitons that are
"brightened" due to defect-induced mixing of states with different parity
and/or spin. Time-resolved PL studies on single nanotubes reveal a significant
reduction of the bright exciton lifetime upon brightening of the dark excitons.
The lowest energy dark state has longer lifetimes and is not in thermal
equilibrium with the bright state.


title:
Metallicity determination in gas-rich galaxies with semiempirical
  methods

abstract:
  A study of the precision of the semiempirical methods used in the
determination of the chemical abundances in gas-rich galaxies is carried out.
In order to do this the oxygen abundances of a total of 438 galaxies were
determined using the electronic temperature, the $R_{23}$ and the P methods.
The new calibration of the P method gives the smaller dispersion for the low
and high metallicity regions, while the best numbers in the turnaround region
are given by the $R_{23}$ method. We also found that the dispersion correlates
with the metallicity. Finally, it can be said that all the semiempirical
methods studied here are quite insensitive to metallicity with a value of
$8.0\pm0.2$ dex for more than 50% of the total sample.
  \keywords{ISM: abundances; (ISM): H {\sc ii} regions}


title:
\sqrt{s}_min: a global inclusive variable for determining the mass scale
  of new physics in events with missing energy at hadron colliders

abstract:
  We propose a new global and fully inclusive variable \sqrt{s}_{min} for
determining the mass scale of new particles in events with missing energy at
hadron colliders. We define \sqrt{s}_{min} as the minimum center-of-mass parton
level energy consistent with the measured values of the total calorimeter
energy E and the total visible momentum \vec{P}. We prove that for an arbitrary
event, \sqrt{s}_{min} is simply given by the formula
\sqrt{s}_{min}=\sqrt{E^2-P_z^2}+\sqrt{\met^2+M_{inv}^2}, where M_{inv} is the
total mass of all invisible particles produced in the event. We use t\bar{t}
production and several supersymmetry examples to argue that the peak in the
\sqrt{s}_{min} distribution is correlated with the mass threshold of the parent
particles originally produced in the event. This conjecture allows a
determination of the heavy superpartner mass scale (as a function of the LSP
mass) in a completely general and model-independent way, and without the need
for any exclusive event reconstruction. In our SUSY examples of several
multijet plus missing energy signals, the accuracy of the mass measurement
based on \sqrt{s}_{min} is typically at the percent level, and never worse than
10%. After including the effects of initial state radiation and multiple parton
interactions, the precision gets worse, but for heavy SUSY mass spectra remains
10%.


title: Algebraic Methods in Discrete Analogs of the Kakeya Problem

abstract:
  We prove the joints conjecture, showing that for any $N$ lines in ${\Bbb
R}^3$, there are at most $O(N^{{3 \over 2}})$ points at which 3 lines intersect
non-coplanarly. We also prove a conjecture of Bourgain showing that given $N^2$
lines in ${\Bbb R}^3$ so that no $N$ lines lie in the same plane and so that
each line intersects a set $P$ of points in at least $N$ points then the
cardinality of the set of points is $\Omega(N^3)$. Both our proofs are
adaptations of Dvir's argument for the finite field Kakeya problem.


title: Crossover transition in bag-like models

abstract:
  We formulate a simple model for a gas of extended hadrons at zero chemical
potential by taking inspiration from the compressible bag model. We show that a
crossover transition qualitatively similar to lattice QCD can be reproduced by
such a system by including some appropriate additional dynamics. Under certain
conditions, at high temperature, the system consist of a finite number of
infinitely extended bags, which occupy the entire space. In this situation the
system behaves as an ideal gas of quarks and gluons.


title: Social networks that matter: Twitter under the microscope

abstract:
  Scholars, advertisers and political activists see massive online social
networks as a representation of social interactions that can be used to study
the propagation of ideas, social bond dynamics and viral marketing, among
others. But the linked structures of social networks do not reveal actual
interactions among people. Scarcity of attention and the daily rythms of life
and work makes people default to interacting with those few that matter and
that reciprocate their attention. A study of social interactions within Twitter
reveals that the driver of usage is a sparse and hidden network of connections
underlying the declared set of friends and followers.


title:
Phenomenology of One-Dimensional Quantum Liquids Beyond the Low-Energy
  Limit

abstract:
  We consider zero temperature behavior of dynamic response functions of 1D
systems near edges of support in momentum-energy plane $(k, \omega).$ The
description of the singularities of dynamic response functions near an edge
$\epsilon(k)$ is given by the effective Hamiltonian of a mobile impurity moving
in a Luttinger liquid. For Galilean-invariant systems, we relate the parameters
of such an effective Hamiltonian to the properties of the function $\epsilon
(k).$ This allows us to express the exponents which characterize singular
response functions of spinless bosonic or fermionic liquids in terms of
$\epsilon(k)$ and Luttinger liquid parameters for any $k.$ For an
antiferromagnetic Heisenberg spin-1/2 chain in a zero magnetic field, SU(2)
invariance fixes the exponents from purely phenomenological considerations.


title: Theory of inter-edge superexchange in zigzag edge magnetism

abstract:
  A graphene nanoribbon with zigzag edges has a gapped magnetic ground state
with an antiferromagnetic inter-edge superexchange interaction. We present a
theory based on asymptotic properties of the Dirac-model ribbon wavefunction
which predicts $W^{-2}$ and $W^{-1}$ ribbon-width dependencies for the
superexchange interaction strength and the charge gap respectively. We find
that, unlike the case of conventional atomic scale superexchange, opposite
spin-orientations on opposite edges of the ribbon are favored by both kinetic
and interaction energies.


title:
Might we eventually understand the origin of the dark matter velocity
  anisotropy?

abstract:
  The density profile of simulated dark matter structures is fairly
well-established, and several explanations for its characteristics have been
put forward. In contrast, the radial variation of the velocity anisotropy has
still not been explained. We suggest a very simple origin, based on the shapes
of the velocity distributions functions, which are shown to differ between the
radial and tangential directions. This allows us to derive a radial variation
of the anisotropy profile which is in good agreement with both simulations and
observations. One of the consequences of this suggestion is that the velocity
anisotropy is entirely determined once the density profile is known. We
demonstrate how this explains the origin of the \gamma-\beta relation, which is
the connection between the slope of the density profile and the velocity
anisotropy. These findings provide us with a powerful tool, which allows us to
close the Jeans equations.


title: Instabilities in the Aether

abstract:
  We investigate the stability of theories in which Lorentz invariance is
spontaneously broken by fixed-norm vector "aether" fields. Models with generic
kinetic terms are plagued either by ghosts or by tachyons, and are therefore
physically unacceptable. There are precisely three kinetic terms that are not
manifestly unstable: a sigma model $(\partial_\mu A_\nu)2$, the Maxwell
Lagrangian $F_{\mu\nu}F^{\mu\nu}$, and a scalar Lagrangian $(\partial_\mu
A^\mu)2$. The timelike sigma-model case is well-defined and stable when the
vector norm is fixed by a constraint; however, when it is determined by
minimizing a potential there is necessarily a tachyonic ghost, and therefore an
instability. In the Maxwell and scalar cases, the Hamiltonian is unbounded
below, but at the level of perturbation theory there are fewer degrees of
freedom and the models are stable. However, in these two theories there are
obstacles to smooth evolution for certain choices of initial data.


title: Sigma-Model Aether

abstract:
  Theories of low-energy Lorentz violation by a fixed-norm "aether" vector
field with two-derivative kinetic terms have a globally bounded Hamiltonian and
are perturbatively stable only if the vector is timelike and the kinetic term
in the action takes the form of a sigma model. Here we investigate the
phenomenological properties of this theory. We first consider the propagation
of modes in the presence of gravity, and show that there is a unique choice of
curvature coupling that leads to a theory without superluminal modes.
Experimental constraints on this theory come from a number of sources, and we
examine bounds in a two-dimensional parameter space. We then consider the
cosmological evolution of the aether, arguing that the vector will naturally
evolve to be orthogonal to constant-density hypersurfaces in a
Friedmann-Robertson-Walker cosmology. Finally, we examine cosmological
evolution in the presence of an extra compact dimension of space, concluding
that a vector can maintain a constant projection along the extra dimension in
an expanding universe only when the expansion is exponential.


title:
Heavy-quark energy loss and thermalization in a strongly coupled SYM
  plasma

abstract:
  Using the AdS/CFT correspondence, we compute the radiative energy loss of a
slowly decelerating heavy quark with mass M moving through a supersymmetric
Yang Mills (SYM) plasma at temperature T at large t'Hooft coupling \lambda. The
calculation is carried out in terms of perturbation in \sqrt{\lambda}T/M, and
the rate of the energy loss is computed up to second order. We explain the
physical meaning of each correction and estimate the thermalization time of a
heavy quark moving in a strongly-coupled plasma.


title:
The Coyote Universe I: Precision Determination of the Nonlinear Matter
  Power Spectrum

abstract:
  Near-future cosmological observations targeted at investigations of dark
energy pose stringent requirements on the accuracy of theoretical predictions
for the clustering of matter. Currently, N-body simulations comprise the only
viable approach to this problem. In this paper we demonstrate that N-body
simulations can indeed be sufficiently controlled to fulfill these requirements
for the needs of ongoing and near-future weak lensing surveys. By performing a
large suite of cosmological simulation comparison and convergence tests we show
that results for the nonlinear matter power spectrum can be obtained at 1%
accuracy out to k~1 h/Mpc. The key components of these high accuracy
simulations are: precise initial conditions, very large simulation volumes,
sufficient mass resolution, and accurate time stepping. This paper is the first
in a series of three, with the final aim to provide a high-accuracy prediction
scheme for the nonlinear matter power spectrum.


title:
Rapidity gap survival in central exclusive diffraction: Dynamical
  mechanisms and uncertainties

abstract:
  We summarize our understanding of the dynamical mechanisms governing rapidity
gap survival in central exclusive diffraction, pp -> p + H + p (H = high-mass
system), and discuss the uncertainties in present estimates of the survival
probability. The main suppression of diffractive scattering is due to inelastic
soft spectator interactions at small pp impact parameters and can be described
in a mean-field approximation (independent hard and soft interactions).
Moderate extra suppression results from fluctuations of the partonic
configurations of the colliding protons. At LHC energies absorptive
interactions of hard spectator partons associated with the gg -> H process
reach the black-disk regime and cause substantial additional suppression,
pushing the survival probability below 0.01.


title: Long-term optical observations of Be/X-Ray binary system V0332+53

abstract:
  We have been monitoring the binary system V0332+53 (optical counterpart is BQ
Cam) since 2004 using 45 cm ROTSEIIId telescope and RTT150 (Russian-Turkish 1.5
m Telescope) located at Bakirlitepe, Antalya, Turkey. We report on the
long-term variability of this system up to the present date. There exists a
fading of 0.2 mag in the light of BQ Cam after MJD 53400. The fading in the
light curve of BQ Cam could be due to a decrease in the density or in the size
of the circumstellar disk.
  We present optical spectroscopic observations obtained before (at MJD 54730)
and during (at MJD 54768) the new X-ray activity reported by Krimm et al.
(2008). The observed Ha line profiles were single-peaked and almost symmetric.
The present EW values are found to be similar to the ones observed during the
fading of infrared magnitudes of Negueruela et al. (1999). Ha emission lines
were found to be red-shifted by ~140 km/s which were larger than the findings
of Corbet et al. (1986). We suggest that brightening of the disk after MJD
54700 may be due to the precession of the disk.


title: On stability of odd-frequency superconducting state

abstract:
  Odd-frequency pairing mechanism of superconductivity has been investigated
for several decades. Nevertheless, its properties, including the thermodynamic
stability, have remained unclear. In particular, it has been argued that the
odd-frequency state is thermodynamically unstable, has an unphysical (anti-)
Meissner effect, and thus can not exist as a homogeneous equilibrium phase. We
argue that this conclusion is incorrect because it implicitly relies on the
inappropriate assumption that the odd-frequency superconductor can be described
by an effective Hamiltonian that breaks the particle conservation symmetry. We
demonstrate that the odd-frequency state can be properly described within the
functional integral approach using non-local-in-time effective action. Within
the saddle point approximation, we find that this phase is thermodynamically
stable, exhibits ordinary Meissner effect, and therefore can be realized as an
equilibrium homogenous state of matter.


title:
Reply to Comment [arXiv:0810.3244v1] by R.S. Decca et al. on
  "Contribution of drifting carriers to the Casimir-Lifshitz and Casimir-Polder
  interactions with semiconductor materials"

abstract:
  We show that the claims expressed in the Comment arXiv:0810.3244v1 by R.S.
Decca et al against our paper, D.A.R. Dalvit and S.K. Lamoreaux, Phys. Rev.
Lett. {\bf 101}, 163203 (2008), are wrong and manifestly inconsistent with
basic principles of statistical physics.


title:
Icosahedral (A5) Family Symmetry and the Golden Ratio Prediction for
  Solar Neutrino Mixing

abstract:
  We investigate the possibility of using icosahedral symmetry as a family
symmetry group in the lepton sector. The rotational icosahedral group, which is
isomorphic to A5, the alternating group of five elements, provides a natural
context in which to explore (among other possibilities) the intriguing
hypothesis that the solar neutrino mixing angle is governed by the golden
ratio. We present a basic toolbox for model-building using icosahedral
symmetry, including explicit representation matrices and tensor product rules.
As a simple application, we construct a minimal model at tree level in which
the solar angle is related to the golden ratio, the atmospheric angle is
maximal, and the reactor angle vanishes to leading order. The approach provides
a rich setting in which to investigate the flavor puzzle of the Standard Model.


title:
Theory of Tunneling Spectroscopy in a Mn$_{12}$ Single-Electron
  Transistor by Density-Functional Theory Methods

abstract:
  We consider tunneling transport through a Mn$_{12}$ molecular magnet using
spin density functional theory. A tractable methodology for constructing
many-body wavefunctions from Kohn-Sham orbitals allows for the determination of
spin-dependent matrix elements for use in transport calculations. The tunneling
conductance at finite bias is characterized by peaks representing transitions
between spin multiplets, separated by an energy on the order of the magnetic
anisotropy. The energy splitting of the spin multiplets and the spatial part of
their many-body wave functions, describing the orbital degrees of freedom of
the excess charge, strongly affect the electronic transport, and can lead to
negative differential conductance.


title: Nonlocal Gravity Simulates Dark Matter

abstract:
  A nonlocal generalization of Einstein's theory of gravitation is constructed
within the framework of the translational gauge theory of gravity. In the
linear approximation, the nonlocal theory can be interpreted as linearized
general relativity but in the presence of "dark matter" that can be simply
expressed as an integral transform of matter. It is shown that this approach
can accommodate the Tohline-Kuhn treatment of the astrophysical evidence for
dark matter.


title:
Stability of Relativistic Jets from Rotating, Accreting Black Holes via
  Fully Three-Dimensional Magnetohydrodynamic Simulations

abstract:
  Rotating magnetized compact objects and their accretion discs can generate
strong toroidal magnetic fields driving highly magnetized plasmas into
relativistic jets. Of significant concern, however, has been that a strong
toroidal field in the jet should be highly unstable to the non-axisymmetric
helical kink (screw) $m=1$ mode leading to rapid disruption. In addition, a
recent concern has been that the jet formation process itself may be unstable
due to the accretion of non-dipolar magnetic fields. We describe large-scale
fully three-dimensional global general relativistic magnetohydrodynamic
simulations of rapidly rotating, accreting black holes producing jets. We study
both the stability of the jet as it propagates and the stability of the jet
formation process during accretion of dipolar and quadrupolar fields. For our
dipolar model, despite strong non-axisymmetric disc turbulence, the jet reaches
Lorentz factors of $\Gamma\sim 10$ with opening half-angle $\theta_j\sim
5^\circ$ at $10^3$ gravitational radii without significant disruption or
dissipation with only mild substructure dominated by the $m=1$ mode. On the
contrary, our quadrupolar model does not produce a steady relativistic
($\Gamma\gtrsim 3$) jet due to mass-loading of the polar regions caused by
unstable polar fields. Thus, if produced, relativistic jets are roughly stable
structures and may reach up to an external shock with strong magnetic fields.
We discuss the astrophysical implications of the accreted magnetic geometry
playing such a significant role in relativistic jet formation, and we outline
avenues for future work.


title: Decidability of the Equivalence of Multi-Letter Quantum Finite Automata

abstract:
  Multi-letter {\it quantum finite automata} (QFAs) were a quantum variant of
classical {\it one-way multi-head finite automata} (J. Hromkovi\v{c}, Acta
Informatica 19 (1983) 377-384), and it has been shown that this new one-way
QFAs (multi-letter QFAs) can accept with no error some regular languages
$(a+b)^{*}b$ that are unacceptable by the previous one-way QFAs. In this paper,
we study the decidability of the equivalence of multi-letter QFAs, and the main
technical contributions are as follows: (1) We show that any two automata, a
$k_{1}$-letter QFA ${\cal A}_1$ and a $k_{2}$-letter QFA ${\cal A}_2$, over the
same input alphabet $\Sigma$ are equivalent if and only if they are
$(n^2m^{k-1}-m^{k-1}+k)$-equivalent, where $m=|\Sigma|$ is the cardinality of
$\Sigma$, $k=\max(k_{1},k_{2})$, and $n=n_{1}+n_{2}$, with $n_{1}$ and $n_{2}$
being the numbers of states of ${\cal A}_{1}$ and ${\cal A}_{2}$, respectively.
When $k=1$, we obtain the decidability of equivalence of measure-once QFAs in
the literature. It is worth mentioning that our technical method is essentially
different from that for the decidability of the case of single input alphabet
(i.e., $m=1$). (2) However, if we determine the equivalence of multi-letter
QFAs by checking all strings of length not more than $ n^2m^{k-1}-m^{k-1}+k$,
then the worst time complexity is exponential, i.e.,
$O(n^6m^{n^2m^{k-1}-m^{k-1}+2k-1})$. Therefore, we design a polynomial-time
$O(m^{2k-1}n^{8}+km^kn^{6})$ algorithm for determining the equivalence of any
two multi-letter QFAs. Here, the time complexity is concerning the number of
states in the multi-letter QFAs, and $k$ is thought of as a constant.


title: Improved Volterra Kernel Methods with Applications to the Visual System

abstract:
  Volterra analysis and its variants have long been prominent among methods for
modeling multi-input non-linear systems. The product of Volterra analysis, the
Volterra kernels, are particularly suited to quantifying intra- and inter-input
interactions. They are also readily interpretable, which means that they can be
related directly to physical behaviors, and more distantly, to the underlying
processing mechanisms of the system being tested. However, accurate estimation
of a sufficient set of classical kernels is often not possible for complex
systems because the number of kernels that need to be determined, and hence
experiment time, increases radically with system memory, response frequency
bandwidth, and non-linear interaction order. Practical approaches to kernel
estimation often involve forced reductions of the generality of the analysis
that in turn compromise interpretability.
  Here we illustrate the effects on kernel interpretability of two common
reductions, slow-stimulation and the use of binary inputs, using both numerical
simulations and data from a Visual Evoked Potential experiment. We show how a
non-standard version of binary analysis, involving a different coding of the
inputs and the use of particular groupings of kernel slices, improves kernel
interpretability. We bring together, in a comprehensive fashion, all of the
mathematical considerations needed to apply and interpret the results of
Volterra kernel analyses. The input-coding method we describe allows one to
correctly quantify multi-input interactive effects that occur both within the
separate input channels and across them.


title:
Observation of Two-source Interference in the Photoproduction Reaction
  $Au Au \to Au Au \rho^0$

abstract:
  In ultra-peripheral relativistic heavy-ion collisions, a photon from the
electromagnetic field of one nucleus can fluctuate to a quark-antiquark pair
and scatter from the other nucleus, emerging as a $\rho^0$. The $\rho^0$
production occurs in two well-separated (median impact parameters of 20 and 40
fermi for the cases considered here) nuclei, so the system forms a 2-source
interferometer. At low transverse momenta, the two amplitudes interfere
destructively, suppressing $\rho^0$ production. Since the $\rho^0$ decay before
the production amplitudes from the two sources can overlap, the two-pion system
can only be described with an entangled non-local wave function, and is thus an
example of the Einstein-Podolsky-Rosen paradox. We observe this suppression in
200 GeV per nucleon-pair gold-gold collisions. The interference is $87% \pm 5%
{\rm (stat.)}\pm 8%$ (syst.) of the expected level. This translates into a
limit on decoherence due to wave function collapse or other factors, of 23% at
the 90% confidence level.


title: Graph Minors and Minimum Degree

abstract:
  Let $\mathcal{D}_k$ be the class of graphs for which every minor has minimum
degree at most $k$.
  Then $\mathcal{D}_k$ is closed under taking minors.
  By the Robertson-Seymour graph minor theorem, $\mathcal{D}_k$ is
characterised by a finite family of minor-minimal forbidden graphs, which we
denote by $\widehat{\mathcal{D}}_k$.
  This paper discusses $\widehat{\mathcal{D}}_k$ and related topics. We obtain
four main results:
  We prove that every $(k+1)$-regular graph with less than ${4/3}(k+2)$
vertices is in $\widehat{\mathcal{D}}_k$, and this bound is best possible.
  We characterise the graphs in $\widehat{\mathcal{D}}_{k+1}$ that can be
obtained from a graph in $\widehat{\mathcal{D}}_k$ by adding one new vertex.
  For $k\leq 3$ every graph in $\widehat{\mathcal{D}}_k$ is $(k+1)$-connected,
but for large $k$, we exhibit graphs in $\widehat{\mathcal{D}}_k$ with
connectivity 1. In fact, we construct graphs in $\mathcal{D}_k$ with arbitrary
block structure.
  We characterise the complete multipartite graphs in
$\widehat{\mathcal{D}}_k$, and prove analogous characterisations with minimum
degree replaced by connectivity, treewidth, or pathwidth.


title: Total photoproduction cross-section at very high energy

abstract:
  In this paper we apply to photoproduction total cross-section a model we have
proposed for purely hadronic processes and which is based on QCD mini-jets and
soft gluon re-summation. We compare the predictions of our model with the HERA
data as well as with other models. For cosmic rays, our model predicts
substantially higher cross-sections at TeV energies than models based on
factorization but lower than models based on mini-jets alone, without soft
gluons. We discuss the origin of this difference.


title: Pure Quantum Correlations Between Bright Optical Beams

abstract:
  The pure quantum correlations totally independent of the classical coherence
of light have been experimentally demonstrated. By measuring the visibility of
the interference fringes and the correlation variances of amplitude and phase
quadratures between a pair of bright twin optical beams with different
frequencies produced from a non-degenerate optical parametric oscillator, we
found that when classical interference became worse even vanished, the
quadrature quantum correlations were not influenced, completely. The presented
experiment obviously shows the quantum correlations of light do not necessarily
imply the classical coherence.


title:
Stau detection at neutrino telescopes in scenarios with supersymmetric
  dark matter

abstract:
  We have studied the detection of long-lived staus at the IceCube neutrino
telescope, after their production inside the Earth through the inelastic
scattering of high energy neutrinos. The theoretical predictions for the stau
flux are calculated in two scenarios in which the presence of long-lived staus
is naturally associated to viable supersymmetric dark matter. Namely, we
consider the cases with superWIMP (gravitino or axino) and neutralino dark
matter (along the coannihilation region). In both scenarios the maximum value
of the stau flux turns out to be about 1 event/yr in regions with a light stau.
This is consistent with light gravitinos, with masses constrained by an upper
limit which ranges from 0.2 to 15 GeV, depending on the stau mass. Likewise, it
is compatible with axinos with a mass of about 1 GeV and a very low reheating
temperature of order 100 GeV. In the case of the neutralino dark matter this
favours regions with a low value of tan(beta), for which the neutralino-stau
coannihilation region occurs for smaller values of the stau mass. Finally, we
study the case of a general supergravity theory and show how for specific
choices of non-universal soft parameters the predicted stau flux can increase
moderately.


title:
In-gap bound states and tunneling conductance of multiband
  superconductors through a normal/superconductor/superconductor junction

abstract:
  The tunneling conductance between a metal and a multiband s-wave
superconductor with a thin layer of single-band s-wave superconductor
sandwiched in between is examined in this paper. We show that an in-gap peak in
conductance curve is found as a result of the formation of in-gap bound state
between the single-band and multiband superconductor junctions if the phases of
the superconducting order parameters of the multiband superconductor are
frustrated. The implication of this result in determining the gap symmetry of
the iron-based superconductors is discussed.


title:
Simple simulation for electron energy levels in geometrical potential
  wells

abstract:
  An octopus program is demonstrated to generate electron energy levels in
three-dimensional geometrical potential wells. The wells are modeled to have
shapes similar to cone, pyramid and truncated-pyramid. To simulate the electron
energy levels in quantum mechanical scheme like the ones in parabolic band
approximation scheme, the program is run initially to find a suitable electron
mass fraction that can produce ground-state energies in the wells as close to
those in quantum dots as possible and further to simulate excited-state
energies. The programs also produce wavefunctions for exploring and determining
their degeneracies and vibrational normal modes.


title: Polynomial fusion rings of W-extended logarithmic minimal models

abstract:
  The countably infinite number of Virasoro representations of the logarithmic
minimal model LM(p,p') can be reorganized into a finite number of
W-representations with respect to the extended Virasoro algebra symmetry W.
Using a lattice implementation of fusion, we recently determined the fusion
algebra of these representations and found that it closes, albeit without an
identity for p>1. Here, we provide a fusion-matrix realization of this fusion
algebra and identify a fusion ring isomorphic to it. We also consider various
extensions of it and quotients thereof, and introduce and analyze commutative
diagrams with morphisms between the involved fusion algebras and the
corresponding quotient polynomial fusion rings. One particular extension is
reminiscent of the fundamental fusion algebra of LM(p,p') and offers a natural
way of introducing the missing identity for p>1. Working out explicit fusion
matrices is facilitated by a further enlargement based on a pair of mutual
Moore-Penrose inverses intertwining between the W-fundamental and enlarged
fusion algebras.


title:
Generic susceptibilities of the half-filled Hubbard model in infinite
  dimensions

abstract:
  Around a metal-to-insulator transition driven by repulsive interaction (Mott
transition) the single particle excitations and the collective excitations are
equally important. Here we present results for the generic susceptibilities at
zero temperature in the half-filled Hubbard model in infinite dimensions.
Profiting from the high resolution of dynamic density-matrix renormalization at
all energies, results for the charge, spin and Cooper-pair susceptibilities in
the metallic and the insulating phase are computed. In the insulating phase, an
almost saturated local magnetic moment appears. In the metallic phase a
pronounced low-energy peak is found in the spin response.


title:
Multiresolution community detection for megascale networks by
  information-based replica correlations

abstract:
  We use a Potts model community detection algorithm to accurately and
quantitatively evaluate the hierarchical or multiresolution structure of a
graph. Our multiresolution algorithm calculates correlations among multiple
copies ("replicas") of the same graph over a range of resolutions. Significant
multiresolution structures are identified by strongly correlated replicas. The
average normalized mutual information, the variation of information, and other
measures in principle give a quantitative estimate of the "best" resolutions
and indicate the relative strength of the structures in the graph. Because the
method is based on information comparisons, it can in principle be used with
any community detection model that can examine multiple resolutions. Our
approach may be extended to other optimization problems. As a local measure,
our Potts model avoids the "resolution limit" that affects other popular
models. With this model, our community detection algorithm has an accuracy that
ranks among the best of currently available methods. Using it, we can examine
graphs over 40 million nodes and more than one billion edges. We further report
that the multiresolution variant of our algorithm can solve systems of at least
200000 nodes and 10 million edges on a single processor with exceptionally high
accuracy. For typical cases, we find a super-linear scaling, O(L^{1.3}) for
community detection and O(L^{1.3} log N) for the multiresolution algorithm
where L is the number of edges and N is the number of nodes in the system.


title: Spatially resolved spectroscopy of monolayer graphene on SiO2

abstract:
  We have carried out scanning tunneling spectroscopy measurements on
exfoliated monolayer graphene on SiO$_2$ to probe the correlation between its
electronic and structural properties. Maps of the local density of states are
characterized by electron and hole puddles that arise due to long range
intravalley scattering from intrinsic ripples in graphene and random charged
impurities. At low energy, we observe short range intervalley scattering which
we attribute to lattice defects. Our results demonstrate that the electronic
properties of graphene are influenced by intrinsic ripples, defects and the
underlying SiO$_2$ substrate.


title: Towards the Probabilistic Earth-System Model

abstract:
  Multi-model ensembles provide a pragmatic approach to the representation of
model uncertainty in climate prediction. However, such representations are
inherently ad hoc, and, as shown, probability distributions of climate
variables based on current-generation multi-model ensembles, are not accurate.
Results from seasonal re-forecast studies suggest that climate model ensembles
based on stochastic-dynamic parametrisation are beginning to outperform
multi-model ensembles, and have the potential to become significantly more
skilful than multi-model ensembles.
  The case is made for stochastic representations of model uncertainty in
future-generation climate prediction models. Firstly, a guiding characteristic
of the scientific method is an ability to characterise and predict uncertainty;
individual climate models are not currently able to do this. Secondly, through
the effects of noise-induced rectification, stochastic-dynamic parametrisation
may provide a (poor man's) surrogate to high resolution. Thirdly,
stochastic-dynamic parametrisations may be able to take advantage of the
inherent stochasticity of electron flow through certain types of low-energy
computer chips, currently under development.
  These arguments have particular resonance for next-generation Earth-System
models, which purport to be comprehensive numerical representations of climate,
and where integrations at high resolution may be unaffordable.


title: Evolutionary dynamics and fixation probabilities in directed networks

abstract:
  We investigate the evolutionary dynamics in directed and/or weighted
networks. We study the fixation probability of a mutant in finite populations
in stochastic voter-type dynamics for several update rules. The fixation
probability is defined as the probability of a newly introduced mutant in a
wild-type population taking over the entire population. In contrast to the case
of undirected and unweighted networks, the fixation probability of a mutant in
directed networks is characterized not only by the degree of the node that the
mutant initially invades but by the global structure of networks. Consequently,
the gross connectivity of networks such as small-world property or modularity
has a major impact on the fixation probability.


title:
Directionality of contact networks suppresses selection pressure in
  evolutionary dynamics

abstract:
  Individuals of different types, may it be genetic, cultural, or else, with
different levels of fitness often compete for reproduction and survival. A
fitter type generally has higher chances of disseminating their copies to other
individuals. The fixation probability of a single mutant type introduced in a
population of wild-type individuals quantifies how likely the mutant type
spreads. How much the excess fitness of the mutant type increases its fixation
probability, namely, the selection pressure, is important in assessing the
impact of the introduced mutant. Previous studies mostly based on undirected
and unweighted contact networks of individuals showed that the selection
pressure depends on the structure of networks and the rule of reproduction.
Real networks underlying ecological and social interactions are usually
directed or weighted. Here we examine how the selection pressure is modulated
by directionality of interactions under several update rules. Our conclusions
are twofold. First, directionality discounts the selection pressure for
different networks and update rules. Second, given a network, the update rules
in which death events precede reproduction events significantly decrease the
selection pressure than the other rules.


title:
$B_s^0 - \bar B_s^0$ mixing and $b \to s $ transitions in isosinglet
  down quark model

abstract:
  The recent observation of the mass difference in $B_s$ system seems to be not
in complete agreement with the corresponding standard model value. We consider
the model with an extra vector like down quark to explain this discrepancy and
obtain the constraints on the new physics parameters. Thereafter, we show that
with these new constraints this model can successfully explain other observed
deviations associated with $b \to s$ transitions, namely, $B_s \to \psi \phi$,
$B\to K \pi$ and $B\to \phi K_s$.


title: Open Orbits and Augmentations of Dynkin Diagrams

abstract:
  Given any representation V of a complex linear reductive Lie group G_0, we
show that a larger semi-simple Lie group G with g=g_0 + V + V* + ..., exists
precisely when V has a finite number of G_0-orbits. In particular, V admits an
open G_0-orbit. Furthermore, this corresponds to an augmentation of the Dynkin
diagram of g_0.
  The representation theory of g should be useful in describing the geometry of
manifolds with stable forms as studied by Hitchin.


title:
Time dependence of cosmological and inflationary parameters in slow-roll
  inflation

abstract:
  The dependence of cosmological and inflationary parameters on time during the
last 60 e-folds in inflation is investigated using a slow-roll inflation model.
The time dependence of the inflaton field is calculated for the case of chaotic
inflation by a numerical method rather than the familiar approximations. It is
found that the Hubble parameter and the spectral index decrease in the last 60
e-folds. The dependence of the power spectrum of the curvature perturbation on
the size perturbation k is calculated numerically, and it is shown that the
overall constant value of the power spectrum thus determined differs from that
given by the familiar method. However, the k-dependent spectra of the numerical
calculation, the Bessel function approximation, and the familiar Taylor
expansion are all found to be consistent.


title: Hilbert geometry of polytopes

abstract:
  It is shown that the Hilbert metric on the interior of a convex polytope is
bilipschitz to a normed vector space of the same dimension.


title: Tachyon warm inflationary universe model in the weak dissipative regime

abstract:
  Warm inflationary universe model in a tachyon field theory is studied in the
weak dissipative regime. We develop our model for an exponential potential and
the dissipation parameter $\Gamma=\Gamma_0$=constant. We describe scalar and
tensor perturbations for this scenario.


title: Yb$_3$Pt$_4$: A New Route to Quantum Criticality

abstract:
  We have studied the evolution of the weakly first order antiferromagnetic
transition in heavy fermion Yb$_3$Pt$_4$ using a combination of specific heat,
magnetic susceptibility, and electrical resistivity experiments. We show that
magnetic fields suppress the Neel temperature, as well as the specific heat
jump, the latent heat, and the entropy of the transition, driving a critical
endpoint at 1.2 K and 1.5 T. At higher fields, the antiferromagnetic transition
becomes second order, and this line of transitions in turn terminates at a
quantum critical point at 1.62 T. Both the ordered and high field paramagnetic
states are Fermi liquids at low temperature, although the former has a much
larger magnetic susceptibility and stronger quasiparticle scattering. Unlike
previously studied quantum critical systems, the quasiparticle mass in
Yb$_3$Pt$_4$ does not diverge at the quantum critical point, implying that here
the quasiparticle interactions drive the zero temperature transition. The Fermi
liquid parameters are nearly field-independent in the ordered state, indicating
that the fluctuations never become fully critical, as their divergences are
interrupted by the first order antiferromagnetic transition.


title: Heavy Quark Effects in the Virtual Photon Structure Functions

abstract:
  We investigate the heavy quark mass effects in the virtual photon structure
functions $F_{2}^{\gamma}(x, Q^2, P^2)$ and $F_{L}^{\gamma}(x, Q^2, P^2)$ in
the framework of the mass-independent renormalization group equation (RGE). We
study a formalism in which the heavy quark mass effects are treated based on
parton picture as well as on the operator product expansion (OPE), and perform
the numerical evaluation of $F_{\rm eff}^{\gamma}(x, Q^2, P^2)$ to the
next-leading order (NLO) in QCD.


title:
Both necessary and sufficient conditions for Bayesian exponential
  consistency

abstract:
  The last decade has seen a remarkable development in the theory of
asymptotics of Bayesian nonparametric procedures. Exponential consistency has
played an important role in this area. It is known that the condition of $f_0$
being in the Kullback-Leibler support of the prior cannot ensure exponential
consistency of posteriors. Many authors have obtained additional sufficient
conditions for exponential consistency of posteriors, see, for instance,
Schwartz (1965), Barron, Schervish and Wasserman (1999), Ghosal, Ghosh and
Ramamoorthi (1999), Walker (2004), Xing and Ranneby (2008). However, given the
Kullback-Leibler support condition, less is known about both necessary and
sufficient conditions. In this paper we give one type of both necessary and
sufficient conditions. As a consequence we derive a simple sufficient condition
on Bayesian exponential consistency, which is weaker than the previous
sufficient conditions.


title: Embedding solenoids in foliations

abstract:
  In this paper we find smooth embeddings of solenoids in smooth foliations. We
show that if a smooth foliation F of a manifold M contains a compact leaf L
with H^1(L;R)= 0 and if the foliation is a product foliation in some saturated
open neighbourhood U of L, then there exists a foliation F' on M which is
C^1-close to F, and F' has an uncountable set of solenoidal minimal sets
contained in U that are pair wise non-homeomorphic. If H^1(L;R) is not 0, then
it is known that any sufficiently small perturbation of F contains a saturated
product neighbourhood. Thus, our result can be thought of as an instability
result complementing the stability results of Reeb, Thurston and Langevin and
Rosenberg.


title: Retinal oscillations carry visual information to cortex

abstract:
  Thalamic relay cells fire action potentials that transmit information from
retina to cortex. The amount of information that spike trains encode is usually
estimated from the precision of spike timing with respect to the stimulus.
Sensory input, however, is only one factor that influences neural activity. For
example, intrinsic dynamics, such as oscillations of networks of neurons, also
modulate firing pattern. Here, we asked if retinal oscillations might help to
convey information to neurons downstream. Specifically, we made whole-cell
recordings from relay cells to reveal retinal inputs (EPSPs) and thalamic
outputs (spikes) and analyzed these events with information theory. Our results
show that thalamic spike trains operate as two multiplexed channels. One
channel, which occupies a low frequency band (<30 Hz), is encoded by average
firing rate with respect to the stimulus and carries information about local
changes in the image over time. The other operates in the gamma frequency band
(40-80 Hz) and is encoded by spike time relative to the retinal oscillations.
Because these oscillations involve extensive areas of the retina, it is likely
that the second channel transmits information about global features of the
visual scene. At times, the second channel conveyed even more information than
the first.


title: New results for Petrov type D pure radiation fields

abstract:
  We present a new family of Petrov type D pure radiation spacetimes with a
shear-free, non-diverging geodesic principal null congruence.


title: Invariant Measures on Stationary Bratteli Diagrams

abstract:
  We study dynamical systems acting on the path space of a stationary
(non-simple) Bratteli diagram. For such systems we explicitly describe all
ergodic probability measures invariant with respect to the tail equivalence
relation (or the Vershik map). These measures are completely described by the
incidence matrix of the diagram. Since such diagrams correspond to substitution
dynamical systems, this description gives an algorithm for finding invariant
probability measures for aperiodic non-minimal substitution systems. Several
corollaries of these results are obtained. In particular, we show that the
invariant measures are not mixing and give a criterion for a complex number to
be an eigenvalue for the Vershik map.


title: Chebyshev Knots

abstract:
  A Chebyshev knot is a knot which admits a parametrization of the form $
x(t)=T_a(t); \ y(t)=T_b(t) ; \ z(t)= T_c(t + \phi), $ where $a,b,c$ are
pairwise coprime, $T_n(t)$ is the Chebyshev polynomial of degree $n,$ and $\phi
\in \RR .$ Chebyshev knots are non compact analogues of the classical Lissajous
knots. We show that there are infinitely many Chebyshev knots with $\phi = 0.$
We also show that every knot is a Chebyshev knot.


title:
Highest weight categories arising from Khovanov's diagram algebra III:
  category O

abstract:
  We prove that integral blocks of parabolic category O associated to the
subalgebra gl(m) x gl(n) of gl(m+n) are Morita equivalent to quasi-hereditary
covers of generalised Khovanov algebras. Although this result is in principle
known, the existing proof is quite indirect, going via perverse sheaves on
Grassmannians. Our new approach is completely algebraic, exploiting Schur-Weyl
duality for higher levels. As a by-product we get a concrete combinatorial
construction of 2-Kac-Moody representations in the sense of Rouquier
corresponding to level two weights in finite type A.


title: Communicating the Difference of Correlated Gaussian Sources Over a MAC

abstract:
  This paper considers the problem of transmitting the difference of two
jointly Gaussian sources over a two-user additive Gaussian noise multiple
access channel (MAC). The goal is to recover this difference within an average
mean squared error distortion criterion. Each transmitter has access to only
one of the two Gaussian sources and is limited by an average power constraint.
In this work, a lattice coding scheme that achieves a distortion within a
constant of a distortion lower bound is presented if the signal to noise ratio
(SNR) is greater than a threshold. Further, uncoded transmission is shown to be
worse in performance to lattice coding methods. An alternative lattice coding
scheme is presented that can potentially improve on the performance of uncoded
transmission.