title: Dynamics of Bloch Oscillations in Disordered Lattice Potentials

abstract:
  We present a detailed analysis of the dynamics of Bloch oscillations of
Bose-Einstein condensates in disordered lattice potentials. Due to the disorder
and the interparticle interactions these oscillations undergo a dephasing,
reflected in a damping of the center of mass oscillations, which should be
observable under realistic experimental conditions. The interplay between
interactions and disorder is far from trivial, ranging from an
interaction-enhanced damping due to modulational instability for strong
interactions, to an interaction-reduced damping due to a dynamical screening of
the disorder potential.


title: The Dark Side of ROTSE-III Prompt GRB Observations

abstract:
  We present several cases of optical observations during gamma-ray bursts
(GRBs) which resulted in prompt limits but no detection of optical emission.
These limits constrain the prompt optical flux densities and the optical
brightness relative to the gamma-ray emission. The derived constraints fall
within the range of properties observed in GRBs with prompt optical detections,
though at the faint end of optical/gamma flux ratios. The presently accessible
prompt optical limits do not require a different set of intrinsic or
environmental GRB properties, relative to the events with prompt optical
detections.


title:
Evidence for Three Subpopulations of Globular Clusters in the Early-Type
  Post-Starburst Shell Galaxy AM 0139-655

abstract:
  We present deep HST ACS images of the post-starburt shell galaxy AM 0139-655.
We find evidence for the presence of three distinct globular cluster
subpopulations associated with this galaxy: a centrally concentrated young
population (~ 0.4 Gyr), an intermediate age population (~ 1 Gyr) and an old,
metal-poor population similar to that seen around normal galaxies. The g-I
color distribution of the clusters is bimodal with peaks at 0.85 and 1.35. The
redder peak at g-I=1.35 is consistent with the predicted color for an old
metal-poor population. The clusters associated with the peak at g-I=0.85 are
centrally concentrated and interpreted as a younger and more metal-rich
population. We suggest that these clusters have an age of ~ 0.4 Gyr and solar
metallicity based on a comparison with population synthesis models. The
luminosity function of these "blue" clusters is well represented by a power
law. Interestingly, the brightest shell associated with the galaxy harbors some
of the youngest clusters observed. This seems to indicate that the same merger
event was responsible for the formation of both the shells and the young
clusters. The red part of the color distribution contains several very bright
clusters, which are not expected for an old, metal-poor population.
Furthermore, the luminosity function of the "red" GCs cannot be fit well by
either a single gaussian or a single power law. A composite (gaussian + power
law) fit to the LF of the red clusters yields both a low rms and very plausible
properties for an old population plus an intermediate-age population of GCs.
Hence, we suggest that the red clusters in AM 0139-655 consist of two distinct
GC subpopulations, one being an old, metal-poor population as seen in normal
galaxies and one having formed during a recent dissipative galaxy merger.


title: Photon emission rate from atomic systems in the CSL model

abstract:
  We calculate the photon emission rate from a general atomic system in the
mass- proportional CSL model. For an isolated charged particle emitting
kilovolt gamma rays, our results agree with those obtained by Fu. For a neutral
atomic system, photon emission is strongly suppressed for photon wavelengths
much larger than the atomic radius. However, for kilovolt gamma rays, Fu's
result is modified by a structure factor that is of order unity, giving no rate
suppression. Our calculation is readily generalized to the case of non-white
noise, noise couplings that are not mass-proportional, and general
(non-Gaussian) spatial correlation functions, and corresponding results are
given. We briefly discuss the implications of our calculation for upper bounds
on the CSL model parameters.


title:
Stress Tensor of Static Dipoles in strongly coupled $\cal{N}$=4 Gauge
  Theory

abstract:
  In the context of the AdS/CFT correspondence we calculate the induced stress
tensor of static dipoles (electric-electric and electric-magnetic) in a
strongly coupled ${\cal N}=4$ SYM gauge theory, by solving the linearized
Einstein equation with Maldecena string as a source. Analytic expressions are
given for the far-field and a near-field close to one charge, and compared to
what one has in weak coupling. The result can be compared to lattice results
for QCD-like theories in a deconfined but strongly coupled regime.


title: Towards an analytical theory for charged hard spheres

abstract:
  Ion mixtures require an exclusion core to avoid collapse. The Debye Hueckel
theory, where ions are point charges, is accurate only in the limit of infinite
dilution. The MSA is the embedding of hard cores into DH, is valid for higher
densities. In the MSA the properties of any ionic mixture can be represented by
a single screening parameter $\Gamma$. For equal ionic size restricted model is
obtained from the Debye parameter $\kappa$. This one parameter representation
(BIMSA) is valid for complex and associating systems, such as the general
n-polyelectrolytes. The BIMSA is the only theory that satisfies the infinite
dilution limit of the DH theory for any chain length. The contact pair
distribution function of hard ions mixture is a functional of $\Gamma$ and a
small mean field parameter. This yields good agreement with the Monte Carlo
(Bresme et al. Phys. Rev. E {\textbf 51} 289 (1995)) .


title:
Accurate theoretical fits to laser ARPES EDCs in the normal phase of
  cuprate superconductors

abstract:
  Anderson has recently proposed a theory of the strange metal state above Tc
in the high Tc superconductors. [arXiv:cond-mat/0512471] It is based on the
idea that the unusual transport properties and spectral functions are caused by
the strong Mott- Hubbard interactions and can be computed by using the formal
apparatus of Gutzwiller projection. In ref. 1 Anderson computed only the
tunneling spectrum and the power-law exponent of the infrared conductivity. He
had calculated the energy distribution curves (EDCs) in angle resolved
photoemission spectroscopy (ARPES) but was discouraged when these differed
radically from the best ARPES measurements available at the time, and did not
include them. In this letter we compare the spectral functions computed within
this model to the novel laser-ARPES data of the Dessau group.These are found to
capture the shape of the experimental EDCs with unprecedented accuracy and in
principle have only one free parameter.


title: ACM sets of points in multiprojective space

abstract:
  If X is a finite set of points in a multiprojective space P^n1 x ... x P^nr
with r >= 2, then X may or may not be arithmetically Cohen-Macaulay (ACM). For
sets of points in P^1 x P^1 there are several classifications of the ACM sets
of points. In this paper we investigate the natural generalizations of these
classifications to an arbitrary multiprojective space. We show that each
classification for ACM points in P^1 x P^1 fails to extend to the general case.
We also give some new necessary and sufficient conditions for a set of points
to be ACM.


title: Separators of points in a multiprojective space

abstract:
  In this note we develop some of the properties of separators of points in a
multiprojective space. In particular, we prove multigraded analogs of results
of Geramita, Maroscia, and Roberts relating the Hilbert function of X and X
\{P} via the degree of a separator, and Abrescia, Bazzotti, and Marino relating
the degree of a separator to shifts in the minimal multigraded free resolution
of the ideal of points.


title: Interaction-controlled transport of an ultracold Fermi gas

abstract:
  We explore the transport properties of an interacting Fermi gas in a
three-dimensional optical lattice. The center of mass dynamics of the atoms
after a sudden displacement of the trap minimum is monitored for different
interaction strengths and lattice fillings. With increasingly strong attractive
interactions the weakly damped oscillation, observed for the non-interacting
case, turns into a slow relaxational drift. Tuning the interaction strength
during the evolution allows us to dynamically control the transport behavior.
Strong attraction between the atoms leads to the formation of local pairs with
a reduced tunneling rate. The interpretation in terms of pair formation is
supported by a measurement of the number of doubly occupied lattice sites. This
quantity also allows us to determine the temperature of the non-interacting gas
in the lattice to be as low as (27\pm2)% of the Fermi temperature.


title: The Nature of CO Emission From z~6 Quasars

abstract:
  We investigate the nature of CO emission from z~6 quasars by combining
non-LTE radiative transfer calculations with merger-driven models of z~6 quasar
formation that arise naturally in LCDM cosmological simulations. We consider
four model quasars formed in 10^12-10^13 M_sun halos from different merging
histories. Our main results follow. Owing to massive starbursts and funneling
of dense gas into the nuclear regions of merging galaxies, the CO is highly
excited and the flux density peaks between J=5-8. The CO morphology of z~6
quasars often exhibits multiple emission peaks which arise from H2
concentrations which have not yet fully coalesced. Quasars at z~6 display a
large range of sightline dependent line widths such that the lines are
narrowest when the rotating H2 gas associated with the quasar is viewed face-on
(when L_B is largest), and broadest when the gas is seen edge-on (when L_B is
lowest). Thus for all models selection effects exist such that quasars selected
for optical luminosity are preferentially face-on which may result in detected
CO line widths narrower than the median. The sightline averaged line width is
reflective of the circular velocity (V_c) of the host halo, and ranges from
sigma~300-650 km/s. For optically selected QSOs, 10-25% (halo-mass dependant)
of sightlines have narrow line widths compatible with the sole CO detection at
z>6, J1148+5251. When accounting for both the temporal evolution of CO line
widths, as well as the redshift evolution of halo V_c, these models
self-consistently account for the CO line widths of both z~2 sub-mm galaxies
and QSO's. Finally, the dynamical mass derived from the sightline averaged line
widths provides a good estimate of the total mass, and allows for a stellar
bulge and SMBH consistent with the local M_BH-M_bulge relation. [abridged]


title: The Accretion Geometry in Radio-Loud Active Galaxies

abstract:
  We review the latest attempts to determine the accretion geometry in
radio-loud active galactic nuclei (AGN). These objects, which comprise ~10-20%
of the AGN population, produce powerful collimated radio jets that can extend
thousands of parsecs from the center of the host galaxy. Recent multiwavelength
surveys have shown that radio-loudness is more common in low-luminosity AGN
than in higher luminosity Seyfert galaxies or quasars. These low-luminosity AGN
have small enough accretion rates that they are most likely accreting via a
geometrically thick and radiatively inefficient accretion flow. In contrast,
X-ray spectroscopic observations of three higher luminosity broad-line radio
galaxies (3C 120, 4C+74.26 and PG 1425+267) have found evidence for an
untruncated thin disk extending very close to the black hole. These tentative
detections indicate that, for this class of radio-loud AGN, the accretion
geometry is very similar to their radio-quiet counterparts. These observations
suggest that there are three conditions to jet formation that must be
satisfied: the presence of a rapidly spinning black hole, an accretion flow
with a large H/r ratio, and a favorable magnetic field geometry.


title: A parameterization of the Fermat curves satisfying x^(2N)+y^(2N)=1

abstract:
  Note that the family of closed curves C_N={(x,y)\in R^2;x^(2N)+y^(2N)=1} for
N=1,2,3,... approaches the boundary of [-1,1]^2 as N \to \infty. In this paper
we exhibit a natural parameterization of these curves and generalize to a
larger class of equations.


title:
The Distances to Open Clusters from Main-Sequence Fitting. IV. Galactic
  Cepheids, the LMC, and the Local Distance Scale

abstract:
  We derive the basic properties of seven Galactic open clusters containing
Cepheids and construct their period-luminosity (P-L) relations. For our cluster
main-sequence fitting we extend previous Hyades-based empirical
color-temperature corrections to hotter stars using the Pleiades as a template.
We use BVI_{C}JHK_{s} data to test the reddening law, and include metallicity
effects to perform a more comprehensive study for our clusters than prior
efforts. The ratio of total to selective extinction R_V that we derive is
consistent with expectations. Assuming the LMC P-L slopes, we find <M_V> =
-3.93 +/- 0.07 (statistical) +/- 0.14 (systematic) for 10-day period Cepheids,
which is generally fainter than those in previous studies. Our results are
consistent with recent HST and Hipparcos parallax studies when using the
Wesenheit magnitudes W(VI). Uncertainties in reddening and metallicity are the
major remaining sources of error in the V-band P-L relation, but a higher
precision could be obtained with deeper optical and near-infrared cluster
photometry. We derive distances to NGC4258, the LMC, and M33 of (m - M)_0 =
29.28 +/- 0.10, 18.34 +/- 0.06, and 24.55 +/- 0.28, respectively, with an
additional systematic error of 0.16 mag in the P-L relations. The distance to
NGC4258 is in good agreement with the geometric distance derived from water
masers [\Delta (m - M)_0 = 0.01 +/- 0.24]; our value for M33 is less consistent
with the distance from an eclipsing binary [\Delta (m - M)_0 = 0.37 +/- 0.34];
our LMC distance is moderately shorter than the adopted distance in the HST Key
Project, which formally implies an increase in the Hubble constant of 7% +/-
8%.


title:
Muon production in low-energy electron-nucleon and electron-nucleus
  scattering

abstract:
  Recently, muon production in electron-proton scattering has been suggested as
a possible candidate reaction for the identification of lepton-flavor violation
due to physics beyond the Standard Model. Here we point out that the
Standard-Model processes $e^- p \to \mu^- p \bar{\nu}_\mu \nu_e$ and $e^- p \to
e^- n \mu^+ \nu_\mu$ can cloud potential beyond-the-Standard-Model signals in
electron-proton collisions. We find that Standard-Model $e p \to \mu X$ cross
sections exceed those from lepton-flavor-violating operators by several orders
of magnitude. We also discuss the possibility of using a nuclear target to
enhance the $e p \to \mu X$ signal.


title: Detecting Early Galaxies Through Their 21-cm Signature

abstract:
  New observations over the next few years of the emission of distant objects
will help unfold the chapter in cosmic history around the era of the first
galaxies. These observations will use the neutral hydrogen emission or
absorption at a wavelength of 21-cm as a detector of the hydrogen abundance. We
predict the signature on the 21-cm signal of the early generations of galaxies.
We calculate the 21-cm power spectrum including two physical effects that were
neglected in previous calculations. The first is the redistribution of the UV
photons from the first galaxies due to their scattering off of the neutral
hydrogen, which results in an enhancement of the 21-cm signal. The second is
the presence of an ionized hydrogen bubble near each source, which produces a
cutoff at observable scales. We show that the resulting clear signature in the
21-cm power spectrum can be used to detect and study the population of galaxies
that formed just 200 million years after the Big Bang.


title:
A Model of Turbulence in Magnetized Plasmas: Implications for the
  Dissipation Range in the Solar Wind

abstract:
  This paper studies the turbulent cascade of magnetic energy in weakly
collisional magnetized plasmas. A cascade model is presented, based on the
assumptions of local nonlinear energy transfer in wavenumber space, critical
balance between linear propagation and nonlinear interaction times, and the
applicability of linear dissipation rates for the nonlinearly turbulent plasma.
The model follows the nonlinear cascade of energy from the driving scale in the
MHD regime, through the transition at the ion Larmor radius into the kinetic
Alfven wave regime, in which the turbulence is dissipated by kinetic processes.
The turbulent fluctuations remain at frequencies below the ion cyclotron
frequency due to the strong anisotropy of the turbulent fluctuations,
k_parallel << k_perp (implied by critical balance). In this limit, the
turbulence is optimally described by gyrokinetics; it is shown that the
gyrokinetic approximation is well satisfied for typical slow solar wind
parameters. Wave phase velocity measurements are consistent with a kinetic
Alfven wave cascade and not the onset of ion cyclotron damping. The conditions
under which the gyrokinetic cascade reaches the ion cyclotron frequency are
established. Cascade model solutions imply that collisionless damping provides
a natural explanation for the observed range of spectral indices in the
dissipation range of the solar wind. The dissipation range spectrum is
predicted to be an exponential fall off; the power-law behavior apparent in
observations may be an artifact of limited instrumental sensitivity. The
cascade model is motivated by a programme of gyrokinetic simulations of
turbulence and particle heating in the solar wind.


title: Decaying Dark Energy in Higher-Dimensional Gravity

abstract:
  We use data from observational cosmology to put constraints on
higher-dimensional extensions of general relativity in which the effective
four-dimensional dark-energy density (or cosmological "constant") decays with
time. In particular we study the implications of this decaying dark energy for
the age of the universe, large-scale structure formation, big-bang
nucleosynthesis and the magnitude-redshift relation for Type Ia supernovae. Two
of these tests (age and the magnitude-redshift relation) place modest lower
limits on the free parameter of the theory, a cosmological length scale L akin
to the de Sitter radius. These limits will improve if experimental
uncertainties on supernova magnitudes can be reduced around z=1.


title: Dissipation-Scale Turbulence in the Solar Wind

abstract:
  We present a cascade model for turbulence in weakly collisional plasmas that
follows the nonlinear cascade of energy from the large scales of driving in the
MHD regime to the small scales of the kinetic Alfven wave regime where the
turbulence is dissipated by kinetic processes. Steady-state solutions of the
model for the slow solar wind yield three conclusions: (1) beyond the observed
break in the magnetic energy spectrum, one expects an exponential cut-off; (2)
the widely held interpretation that this dissipation range obeys power-law
behavior is an artifact of instrumental sensitivity limitations; and, (3) over
the range of parameters relevant to the solar wind, the observed variation of
dissipation range spectral indices from -2 to -4 is naturally explained by the
varying effectiveness of Landau damping, from an undamped prediction of -7/3 to
a strongly damped index around -4.


title: Angular distribution of leptons from the decay of massive vector bosons

abstract:
  We examine the transverse momentum $Q_\perp$ dependence of the helicity
structure functions for massive vector bosons of mass $Q$ in hadron reactions.
We demonstrate that large logarithmic terms of the form $\ln(Q/Q_\perp)$ in the
helicity structure functions have the same origin as the logarithmic terms in
the angular-integrated cross section and that they can be resummed to all
orders in the strong coupling $\alpha_s$, in the same way as the
angular-integrated cross section. As a consequence of current conservation, the
resummed part of the helicity structure functions preserves the Lam-Tung
relation as a function of $Q_\perp$ to all orders in $\alpha_s$.


title:
Stable Tameness of Two-Dimensional Polynomial Automorphisms Over a
  Regular Ring

abstract:
  In this paper it is established that all two-dimensional polynomial
automorphisms over a regular ring R are stably tame. In the case R is a
Dedekind Q-algebra, some stronger results are obtained. A key element in the
proof is a theorem which yields the following corollary: Over an Artinian ring
A all two-dimensional polynomial automorphisms having Jacobian determinant one
are stably tame, and are tame if A is a Q-algebra. Another crucial ingredient,
of interest in itself, is that stable tameness is a local property: If an
automorphism is locally tame, then it is stably tame.


title: New Physics Effects in Higgs Decay to Tau Leptons

abstract:
  We study the possible effects of TeV scale new physics (NP) on the rate for
Higgs boson decays to charged leptons, focusing on the tau tau channel which
can be readily studied at the Large Hadron collider. Using an SU(3)_C X SU(2)_L
X U(1)_Y invariant effective theory valid below a NP scale Lambda, we determine
all effective operators up to dimension six that could generate appreciable
contributions to the decay rate and compute the dependence of the rate on the
corresponding operator coefficients. We bound the size of these operator
coefficients based on the scale of the tau mass, naturalness considerations,
and experimental constraints on the tau anomalous magnetic moment. These
considerations imply that contributions to the decay rate from a NP scale
Lambda ~ TeV could be comparable to the prediction based on the SM Yukawa
interaction. A reliable test of the Higgs mechanism for fermion mass generation
via the h-> tau tau channel is possible only after such NP effects are
understood and brought under theoretical control.


title: Consequences of the H-Theorem from Nonlinear Fokker-Planck Equations

abstract:
  A general type of nonlinear Fokker-Planck equation is derived directly from a
master equation, by introducing generalized transition rates. The H-theorem is
demonstrated for systems that follow those classes of nonlinear Fokker-Planck
equations, in the presence of an external potential. For that, a relation
involving terms of Fokker-Planck equations and general entropic forms is
proposed. It is shown that, at equilibrium, this relation is equivalent to the
maximum-entropy principle. Families of Fokker-Planck equations may be related
to a single type of entropy, and so, the correspondence between well-known
entropic forms and their associated Fokker-Planck equations is explored. It is
shown that the Boltzmann-Gibbs entropy, apart from its connection with the
standard -- linear Fokker-Planck equation -- may be also related to a family of
nonlinear Fokker-Planck equations.


title:
Hysteresis of spectral evolution in the soft state of black-hole binary
  LMC X-3

abstract:
  We report the discovery of hysteresis between the x-ray spectrum and
luminosity of black-hole binary LMC X-3. Our observations, with the
Proportional Counter Array on the Rossi X-ray Timing Explorer, took place
entirely within the soft spectral state, dominated by a spectral component that
was fitted well with a multicolor disk blackbody. A power-law component was
seen only during times when the luminosity of the disk blackbody was declining.
The x-ray luminosity at these times was comparable to that seen in transient
systems (x-ray novae) when they return to the hard state at the end of an
outburst. Our observations may represent partial transitions to the hard state;
complete transitions have been seen in this system by Wilms et al. (2001). If
they are related to the soft-to-hard transition in transients, then they
demonstrate that hysteresis effects can appear without a full state transition.
We discuss these observations in the context of earlier observations of
hysteresis within the hard state of binaries 1E 1740.7-2942 and GRS 1758-258
and in relation to published explanations of hysteresis in transients.


title:
A Random Change of Variables and Applications to the Stochastic Porous
  Medium Equation with Multiplicative Time Noise

abstract:
  A change of variables is introduced to reduce certain nonlinear stochastic
evolution equations with multiplicative noise to the corresponding
deterministic equation. The result is then used to investigate a stochastic
porous medium equation.


title: Gluelump spectrum from Coulomb gauge QCD

abstract:
  We compute the energy spectrum of gluelumps defined as gluonic excitations
bound to a localized, static octet source. We are able to reproduce the
nontrivial ordering of the spin-parity levels and show how this is related to
the non-abelian part of the Coulomb interaction between color charges.


title:
Accurate retrieval of structural information from laser-induced
  photoelectron and high-harmonic spectra by few-cycle laser pulses

abstract:
  By analyzing ``exact'' theoretical results from solving the time-dependent
Schr\"odinger equation of atoms in few-cycle laser pulses, we established the
general conclusion that differential elastic scattering and photo-recombination
cross sections of the target ion with {\em free} electrons can be extracted
accurately from laser-generated high-energy electron momentum spectra and
high-order harmonic spectra, respectively. Since both electron scattering and
photoionization (the inverse of photo-recombination) are the conventional means
for interrogating the structure of atoms and molecules, this result shows that
existing few-cycle infrared lasers can be implemented for ultrafast imaging of
transient molecules with temporal resolution of a few femtoseconds.


title: Quasiparticle mirages in the tunneling spectra of d-wave superconductors

abstract:
  We illustrate the importance of many-body effects in the Fourier transformed
local density of states (FT-LDOS) of d-wave superconductors from a model of
electrons coupled to an Einstein mode with energy Omega_0. For bias energies
significantly larger than Omega_0 the quasiparticles have short lifetimes due
to this coupling, and the FT-LDOS is featureless if the electron-impurity
scattering is treated within the Born approximation. In this regime it is
important to include boson exchange for the electron-impurity scattering which
provides a `step down' in energy for the electrons and allows for long
lifetimes. This many-body effect produces qualitatively different results,
namely the presence of peaks in the FT-LDOS which are mirrors of the
quasiparticle interference peaks which occur at bias energies smaller than ~
Omega_0. The experimental observation of these quasiparticle mirages would be
an important step forward in elucidating the role of many-body effects in
FT-LDOS measurements.


title: Rectification and nonlinear transport in chaotic dots and rings

abstract:
  We investigate the nonlinear current-voltage characteristic of mesoscopic
conductors and the current generated through rectification of an alternating
external bias. To leading order in applied voltages both the nonlinear and the
rectified current are quadratic. This current response can be described in
terms of second order conductance coefficients and for a generic mesoscopic
conductor they fluctuate randomly from sample to sample. Due to Coulomb
interactions the symmetry of transport under magnetic field inversion is broken
in a two-terminal setup. Therefore, we consider both the symmetric and
antisymmetric nonlinear conductances separately. We treat interactions
self-consistently taking into account nearby gates.
  The nonlinear current is determined by different combinations of second order
conductances depending on the way external voltages are varied away from an
equilibrium reference point (bias mode). We discuss the role of the bias mode
and circuit asymmetry in recent experiments. In a photovoltaic experiment the
alternating perturbations are rectified, and the fluctuations of the nonlinear
conductance are shown to decrease with frequency. Their asymptotical behavior
strongly depends on the bias mode and in general the antisymmetric conductance
is suppressed stronger then the symmetric conductance.
  We next investigate nonlinear transport and rectification in chaotic rings.
To this extent we develop a model which combines a chaotic quantum dot and a
ballistic arm to enclose an Aharonov-Bohm flux. In the linear two-probe
conductance the phase of the Aharonov-Bohm oscillation is pinned while in
nonlinear transport phase rigidity is lost. We discuss the shape of the
mesoscopic distribution of the phase and determine the phase fluctuations.


title: Random Walks in Random Environments

abstract:
  Random walks provide a simple conventional model to describe various
transport processes, for example propagation of heat or diffusion of matter
through a medium. However, in many practical cases the medium is highly
irregular due to defects, impurities, fluctuations etc., and it is natural to
model this as random environment. In the random walks context, such models are
referred to as Random Walks in Random Environments (RWRE). This is a relatively
new chapter in applied probability and physics of disordered systems, initiated
in the 1970s. Early interest was motivated by some problems in biology,
crystallography and metal physics, but later applications have spread through
numerous areas. After 30 years of extensive work, RWRE remain a very active
area of research, which has already led to many surprising discoveries. The
goal of this article is to give a brief introduction to the beautiful area of
RWRE. The principal model to be discussed is a random walk with
nearest-neighbor jumps in independent identically distributed (i.i.d.) random
environment in one dimension, although we shall also comment on some extensions
and generalizations. The focus is on rigorous results; however, heuristics is
used freely to motivate the ideas and explain the approaches and proofs. In a
few cases, sketches of the proofs have been included, which should help the
reader to appreciate the flavor of results and methods.


title:
The Subaru/XMM-Newton Deep Survey (SXDS). IV. Evolution of Lya Emitters
  from z=3.1 to 5.7 in the 1 deg^2 Field: Luminosity Functions and AGN

abstract:
  We present luminosity functions (LFs) and various properties of Lya emitters
(LAEs) at z=3.1, 3.7, and 5.7, in a 1 deg^2 sky of the Subaru/XMM-Newton Deep
Survey (SXDS) Field. We obtain a photometric sample of 858 LAE candidates based
on deep Subaru/Suprime-Cam imaging data, and a spectroscopic sample of 84
confirmed LAEs from Subaru/FOCAS and VLT/VIMOS spectroscopy in a survey volume
of ~10^6 Mpc^3 with a limiting Lya luminosity of ~3x10^42 erg/s. We derive the
LFs of Lya and UV-continuum (~1500 \AA) for each redshift, taking into account
the statistical error and the field-to-field variation. We find that the
apparent Lya LF shows no significant evolution between z=3.1 and 5.7 within
factors of 1.8 and 2.7 in L* and phi*, respectively. On the other hand, the UV
LF of LAEs increases from z=3.1 to 5.7, indicating that galaxies with Lya
emission are more common at earlier epochs. We identify six LAEs with AGN
activities from our spectra combined with VLA, Spitzer, and XMM-Newton data.
Among the photometrically selected LAEs at z=3.1 and 3.7, only ~1 % show AGN
activities, while the brightest LAEs with logL(Lya) >~ 43.4-43.6 erg/s appear
to always host AGNs. Our LAEs are bluer in UV-continuum color than dropout
galaxies, suggesting lower extinction and/or younger stellar populations. Our
stacking analyses provide upper limits to the radio luminosity and the
f(HeII)/f(Lya) line fraction, and constrain the hidden star formation
(+low-luminosity AGN) and the primordial population in LAEs.


title: Triple Higgs boson production in the Linear Collider

abstract:
  Triple Higgs boson production (3H) may provide essential information to
reconstruct the Higgs potential. We consider 3H-production in the International
Linear Collider (ILC) both in the Minimal Supersymmetric Standard Model (MSSM)
and in the general Two-Higgs-doublet Model (2HDM). We compute the total
cross-section for the various 3H final states, such as H^+ H^- h^0, H^0 A^0
h^0, etc. and compare with the more traditional double Higgs (2H) boson
production processes. While the cross-sections for the 2H final states lie
within the same order of magnitude in both the MSSM and 2HDM, we find that for
the 3H states the maximum 2HDM cross-sections, being of order 0.1 pb, are much
larger than the MSSM ones which in most cases are of order 10^{-6} pb or less.
Actually, the 3H processes could be the dominant mechanism for Higgs boson
production in the 2HDM. Ultimately the origin of the remarkable enhancement of
the 3H channels in the 2HDM case (for both type I and type II models)
originates in the structure of the trilinear Higgs boson couplings. The
extremely clean environment of the ILC should allow a relatively comfortable
tagging of the three Higgs boson events. In view of the fact that the MSSM
contribution is negligible, these events should manifest themselves mainly in
the form of 6 heavy-quark jet final states. Some of these signatures could be
spectacular, and in case of being detected would constitute strong evidence of
an extended Higgs sector of non-supersymmetric origin.


title: Intersection probabilities for a chordal SLE path and a semicircle

abstract:
  We derive a number of estimates for the probability that a chordal SLE path
in the upper half plane H intersects a semicircle centred on the real line. We
prove that if 0<kappa<8 and gamma:[0,infinity) to closure(H) is a chordal SLE
in H from 0 to infinity, then P(gamma[0,infinity) cap C(x;rx) neq emptyset)
asymp r^(4a-1) where a=2/kappa and C(x;rx) denotes the semicircle centred at
x>0 of radius rx, 0<r<1/3, in the upper half plane. As an application of our
results, for 0<kappa<8, we derive an estimate for the diameter of a chordal SLE
path in H between two real boundary points 0 and x>0. For 4<kappa<8, we also
estimate the probability that an entire semicircle on the real line is
swallowed at once by a chordal SLE path in H from 0 to infinity.


title:
The Symmetric Tensor Lichnerowicz Algebra and a Novel Associative
  Fourier-Jacobi Algebra

abstract:
  Lichnerowicz's algebra of differential geometric operators acting on
symmetric tensors can be obtained from generalized geodesic motion of an
observer carrying a complex tangent vector. This relation is based upon
quantizing the classical evolution equations, and identifying wavefunctions
with sections of the symmetric tensor bundle and Noether charges with geometric
operators. In general curved spaces these operators obey a deformation of the
Fourier-Jacobi Lie algebra of sp(2,R). These results have already been
generalized by the authors to arbitrary tensor and spinor bundles using
supersymmetric quantum mechanical models and have also been applied to the
theory of higher spin particles. These Proceedings review these results in
their simplest, symmetric tensor setting. New results on a novel and extremely
useful reformulation of the rank 2 deformation of the Fourier-Jacobi Lie
algebra in terms of an associative algebra are also presented. This new algebra
was originally motivated by studies of operator orderings in enveloping
algebras. It provides a new method that is superior in many respects to common
techniques such as Weyl or normal ordering.


title:
Extinction Corrected Star Formation Rates Empirically Derived from
  Ultraviolet-Optical Colors

abstract:
  Using a sample of galaxies from the Sloan Digital Sky Survey spectroscopic
catalog with measured star-formation rates (SFRs) and ultraviolet (UV)
photometry from the GALEX Medium Imaging Survey, we derived empirical linear
correlations between the SFR to UV luminosity ratio and the UV-optical colors
of blue sequence galaxies. The relations provide a simple prescription to
correct UV data for dust attenuation that best reconciles the SFRs derived from
UV and emission line data. The method breaks down for the red sequence
population as well as for very blue galaxies such as the local ``supercompact''
UV luminous galaxies and the majority of high redshift Lyman Break Galaxies
which form a low attenuation sequence of their own.


title:
Conformal Windows of SU(N) Gauge Theories, Higher Dimensional
  Representations and The Size of The Unparticle World

abstract:
  We present the conformal windows of SU(N) supersymmetric and
nonsupersymmetric gauge theories with vector-like matter transforming according
to higher irreducible representations of the gauge group. We determine the
fraction of asymptotically free theories expected to develop an infrared fixed
point and find that it does not depend on the specific choice of the
representation. This result is exact in supersymmetric theories while it is an
approximate one in the nonsupersymmetric case. The analysis allows us to size
the unparticle world related to the existence of underlying gauge theories
developing an infrared stable fixed point. We find that exactly 50 % of the
asymptotically free theories can develop an infrared fixed point while for the
nonsupersymmetric theories it is circa 25 %. When considering multiple
representations, only for the nonsupersymmetric case, the conformal regions
quickly dominate over the nonconformal ones. For four representations, 70 % of
the asymptotically free space is filled by the conformal region.
  According to our theoretical landscape survey the unparticle physics world
occupies a sizable amount of the particle world, at least in theory space, and
before mixing it (at the operator level) with the nonconformal one.


title: Rational Tate classes

abstract:
  In despair, as Deligne (2000) put it, of proving the Hodge and Tate
conjectures, we can try to find substitutes. For abelian varieties in
characteristic zero, Deligne (1982) constructed a theory of Hodge classes
having many of the properties that the algebraic classes would have if the
Hodge conjecture were known. In this article I investigate whether there exists
a theory of "rational Tate classes" on varieties over finite fields having the
properties that the algebraic classes would have if the Hodge and Tate
conjectures were known. v3. Submitted version.


title: Wormholes in Maximal Supergravity

abstract:
  In this brief note, we reconsider the problem of finding Euclidean wormhole
solutions to maximal supergravity in d dimensions. We find that such solutions
exists for all d less than or equal to 9. However, we argue that, in
toroidally-compactified string theories, these saddle points never contribute
to the path integral because of a tension with U-duality.


title: Traces on operator ideals and arithmetic means

abstract:
  This article - a part of a multipaper project investigating arithmetic mean
ideals - investigates the codimension of commutator spaces [I, B(H)] of
operator ideals on a separable Hilbert space, i.e., ``How many traces can an
ideal support?" We conjecture that the codimension can be only zero, one, or
infinity. Using the arithmetic mean (am) operations on ideals introduced by
Dykema, Figiel, Weiss, and Wodzicki, and the analogous am operations at
infinity that we develop in this article, the conjecture is proven for all
ideals not contained in the largest am-infinity stable ideal and not containing
the smallest am-stable ideal. It is also proven for all soft-edged ideals
(i.e., I= IK(H)) and all soft-complemented ideals (i.e., I= I/K(H)), which
include many classical operator ideals. In the process, we prove that an ideal
of trace class operators supports a unique trace (up to scalar multiples) if
and only if it is am-infinity stable and that, for a principal ideal,
am-infinity stability is equivalent to regularity at infinity of the sequence
of s-numbers of the generator. Furthermore, we apply trace extension methods to
two problems on elementary operators studied by V. Shulman and to
Fuglede-Putnam type problems of the second author.


title: Inductive Definition and Domain Theoretic Properties of Fully Abstract

abstract:
  A construction of fully abstract typed models for PCF and PCF^+ (i.e., PCF +
"parallel conditional function"), respectively, is presented. It is based on
general notions of sequential computational strategies and wittingly consistent
non-deterministic strategies introduced by the author in the seventies.
Although these notions of strategies are old, the definition of the fully
abstract models is new, in that it is given level-by-level in the finite type
hierarchy. To prove full abstraction and non-dcpo domain theoretic properties
of these models, a theory of computational strategies is developed. This is
also an alternative and, in a sense, an analogue to the later game strategy
semantics approaches of Abramsky, Jagadeesan, and Malacaria; Hyland and Ong;
and Nickau. In both cases of PCF and PCF^+ there are definable universal
(surjective) functionals from numerical functions to any given type,
respectively, which also makes each of these models unique up to isomorphism.
Although such models are non-omega-complete and therefore not continuous in the
traditional terminology, they are also proved to be sequentially complete (a
weakened form of omega-completeness), "naturally" continuous (with respect to
existing directed "pointwise", or "natural" lubs) and also "naturally"
omega-algebraic and "naturally" bounded complete -- appropriate generalisation
of the ordinary notions of domain theory to the case of non-dcpos.


title:
Intrinsic Impurity in the High Temperature Superconductor
  Bi_2Sr_2CaCu_2O$_{8+\delta}$

abstract:
  The {}^{17}O NMR spectra of Bi_2Sr_2CaCu_2O$_{8+\delta}$ (Bi-2212) single
crystals were measured in the temperature range from 4 K to 200 K and magnetic
fields from 3 to 29 T, reported here principally at 8 T. The NMR linewidth of
the oxygen in the CuO_{2} plane was found to be magnetically broadened with the
temperature dependence of a Curie law where the Curie coefficient decreases
with increased doping. This inhomogeneous magnetism is an impurity effect
intrinsic to oxygen doping and persists unmodified into the superconducting
state.


title:
Equivariant orbifold structures on the projective line and integrable
  hierarchies

abstract:
  Let $\CP^1_{k,m}$ be the orbifold structure on $\CP^1$ obtained via
uniformizing the neighborhoods of 0 and $\infty$ respectively by $z\mapsto z^k$
and $w\mapsto w^m.$ The diagonal action of the torus on the projective line
induces naturally an orbifold action on $\CP^1_{k,m}.$ In this paper we prove
that if k and m are co-prime then Givental's prediction of the equivariant
total descendent Gromov-Witten potential of $\CP^1_{k,m}$ satisfies certain
Hirota Quadratic Equations (HQE for short). We also show that after an
appropriate change of the variables, similar to Getzler's change in the
equivariant Gromov-Witten theory of $\CP^1$, the HQE turn into the HQE of the
2-Toda hierarchy, i.e., the Gromov-Witten potential of $\CP^1_{k,m}$ is a
tau-function of the 2-Toda hierarchy. More precisely, we obtain a sequence of
tau-functions of the 2-Toda hierarchy from the descendent potential via some
translations. The later condition, that all tau-functions in the sequence are
obtained from a single one via translations, imposes a serious constraint on
the solution of the 2-Toda hierarchy. Our theorem leads to the discovery of a
new integrable hierarchy (we suggest to be called the Equivariant Bi-graded
Toda Hierarchy). We conjecture that this new hierarchy governs, i.e., uniquely
determines, the equivariant Gromov-Witten invariants of $\CP^1_{k,m}.$


title:
Points on Shimura varieties over finite fields: the conjecture of
  Langlands and Rapoport

abstract:
  We state an improved version of the conjecture of Langlands and Rapoport, and
we prove the conjecture for a large class of Shimura varieties. In particular,
we obtain the first proof of the (original) conjecture for Shimura varieties of
PEL-type.


title:
A new characterization for the m-quasiinvariants of S_n and explicit
  basis for two row hook shapes

abstract:
  In 2002, Feigin and Veselov defined the space of m-quasiinvariants for any
Coxeter group, building on earlier work of Chalykh and Veselov. While many
properties of those spaces were proven from this definition, an explicit
computation of a basis was only done in certain cases. In particular, Feigin
and Veselov computed bases for the m-quasiinvariants of dihedral groups,
including S_3, and Felder and Veselov computed the non-symmetric
m-quasiinvariants of lowest degree for general S_n. In this paper, we provide a
new characterization of the m-quasiinvariants of S_n, and use this to provide a
basis for the isotypic component indexed by the partition [n-1,1]. This builds
on a previous paper in which we computed a basis for S_3 via combinatorial
methods.


title: Stacked OSTBC: Error Performance and Rate Analysis

abstract:
  It is well known, that the Alamouti scheme is the only space-time code from
orthogonal design achieving the capacity of a multiple-input multiple-output
(MIMO) wireless communication system with n_T=2 transmit antennas and n_R=1
receive antenna. In this work, we propose the n-times stacked Alamouti scheme
for n_T=2n transmit antennas and show that this scheme achieves the capacity in
the case of n_R=1 receive antenna. This result may regarded as an extension of
the Alamouti case. For the more general case of more than one receive antenna,
we show that if the number of transmit antennas is higher than the number of
receive antennas we achieve a high portion of the capacity with this scheme.
Further, we show that the MIMO capacity is at most twice the rate achieved with
the proposed scheme for all SNR. We derive lower and upper bounds for the rate
achieved with this scheme and compare it with upper and lower bounds for the
capacity. In addition to the capacity analysis based on the assumption of a
coherent channel, we analyze the error rate performance of the stacked OSTBC
with the optimal ML detector and with the suboptimal lattice-reduction (LR)
aided zero-forcing detector. We compare the error rate performance of the
stacked OSTBC with spatial multiplexing (SM) and full-diversity achieving
schemes. Finally, we illustrate the theoretical results by numerical
simulations.


title:
Photocurrent Imaging of p-n Junctions and Local Defects in Ambipolar
  Carbon Nanotube Transistors

abstract:
  We use scanning photocurrent microscopy (SPCM) to investigate the properties
of internal p-n junctions as well as local defects in ambipolar carbon nanotube
(CNT) transistors. Our SPCM images show strong signals near metal contacts
whose polarity and positions change depending on the gate bias. SPCM images
analyzed in conjunction with the overall conductance also indicate the
existence and gate-dependent evolution of internal p-n junctions near contacts
in the n-type operation regime. To determine the p-n junction position and the
depletion width with a nanometer scale resolution, a Gaussian fit was used. We
also measure the electric potential profile of CNT devices at different gate
biases, which shows that both local defects and induced electric fields can be
imaged using the SPCM technique. Our experiment clearly demonstrates that SPCM
is a valuable tool for imaging and optimizing electrical and optoelectronic
properties of CNT based devices.


title: Towards a proof of the conjecture of Langlands and Rapoport

abstract:
  A conference talk discussing the conjecture of Langlands and Rapoport
concerning the structure of the points on a Shimura variety modulo a prime of
good reduction.


title: Vanishing theorems for toric polyhedra

abstract:
  A toric polyhedron is a reduced closed subscheme of a toric variety that are
partial unions of the orbits of the torus action. We prove vanishing theorems
for toric polyhedra. We also give a proof of the $E_1$-degeneration of Hodge to
de Rham type spectral sequence for toric polyhedra in any characteristic.
Finally, we give a very powerful extension theorem for ample line bundles.


title: Combinatorial Aspects of Elliptic Curves

abstract:
  Given an elliptic curve C, we study here $N_k = #C(F_{q^k})$, the number of
points of C over the finite field F_{q^k}. This sequence of numbers, as k runs
over positive integers, has numerous remarkable properties of a combinatorial
flavor in addition to the usual number theoretical interpretations. In
particular we prove that $N_k = - W_k(q, - N_1)$ where W_k(q,t) is a
(q,t)-analogue of the number of spanning trees of the wheel graph. Additionally
we develop a determinantal formula for N_k where the eigenvalues can be
explicitly written in terms of q, N_1, and roots of unity. We also discuss here
a new sequence of bivariate polynomials related to the factorization of N_k,
which we refer to as elliptic cyclotomic polynomials because of their various
properties.


title:
Two Trends of Composition Variation of Zircons and Their Significance in
  Origin Discrimination

abstract:
  Zircons can crystallize in a wide range of physical and chemical conditions.
At the same time, they have high stability and durability. Therefore zircons
can grow and survive in a variety of geological processes. In addition, the
diffusivity of chemical compositions in their crystals is very low.
Consequently,we can trace back the evolution history of the planetary materials
containing zircon by zircon U-Th-Pb geochronology and geochemistry studies.
However, this depends on our ability to decipher its genesis,namely magmatic or
metamorphic origins. In this paper, we have found that there are obvious
differences between magmatic and metamorphic zircons in their chemical
composition zonations. The magmatic zircons exhibit composition zonation of
increasing HfO2, and (UO2 + ThO2) content and decreasing ZrO2/HfO2 ratio and
ZrO2 content from inner to outer parts within each growth zone or from core to
rim of a crysta1. The metamorphic zircons exhibit compositional variation trend
opposite to that of magmatic (igneous) zircons,tending to decrease in HfO2,
(UO2+ ThO2)and increase in ZrO2/HfO2 ratio and ZrO2 from core to rim of a
crystal. These chemical composition variation trends are thought to be
controlled by the crystal chemical features of ions themselves and the
evolution trends of magmatism and metamorphism respectively, and can be used to
identify the genesis of zircons. Their morphological features are also
discussed.


title:
The Minerageny of Two Groups of Zircons from Plagioclase- Amphibolite of
  Mayuan Group in Northern Fujian

abstract:
  Zircons can crystallize in a wide range of physical and chemical conditions.
At the same time, they have high stability and durability. Therefore zircons
can grow and survive in a variety of geological processes. In addition, the
diffusivity of chemical compositions in their crystals is very low.
Consequently,we can trace back the evolution history of the planetary materials
containing zircon with zircon U-Th-Pb geochronology and geochemistry studies.
However, this depends on our ability to decipher its genesis, namely magmatic
or metamorphic origins. In this paper, magmatic and metamorphic zircons were
found from plagioclase-amphibolite samples. Their geneses have been determined
by zircon morphology, chemical composition zonations and geological field
setting combined with their zircon U-Th-Pb ages. We have found obvious
differences in micro-scale Raman spectra between these magmatic and metamorphic
zircons. The magmatic zircons exhibit a high sloping background in their Raman
spectra, but the metamorphic zircons exhibit a low horizontal background in
their Raman spectra, which suggest that the magmatic zircons may contain a much
higher concentration of fluorescent impurities than the metamorphic zircons.
Moreover, reverse variation trends in Raman spectrum peak intensities from core
to rim of a crystal between the magmatic and metamorphic zircons have been
found. We think that this can be attributed to their reverse chemical
composition zonations. These differences can be used to distinguish magmatic
and metamorphic zircons.


title: Collider Signals of Gravitational Fixed Points

abstract:
  Recent studies have shown that the poor perturbative behavior of General
Relativity in the ultraviolet regime may be ameliorated by the existence of a
non-Gaussian fixed point which renders the theory asymptotically safe and
possibly non-perturbatively renormalizable. This results in a running of the
(effective) gravitational coupling such that gravity becomes weaker at high
energies. We parameterize this effective coupling with a form factor and study
its consequences at the LHC and ILC in models with large extra dimensions or
warped extra dimensions. We find significant effects in the processes of
Kaluza-Klein (KK) graviton exchange or resonant KK graviton production in both
the Drell-Yan reaction as well as in $e^+e^-\to f\bar f$. On the otherhand,
processes leading to KK graviton emission show qualitatively less sensitivity
to the presence of a form factor. In addition, we examine tree-level
perturbative unitarity in $2\to 2$ gravity-mediated scattering and find that
this form factor produces a far better behaved amplitude at large center of
mass energies.


title:
Ferromagnetism as a universal feature of nanoparticles of the otherwise
  nonmagnetic oxides

abstract:
  Room-temperature ferromagnetism has been observed in the nanoparticles (7 -
30 nm dia) of nonmagnetic oxides such as CeO2, Al2O3, ZnO, In2O3 and SnO2. The
saturated magnetic moments in CeO_2 and Al_2O_3 nanoparticles are comparable to
those observed in transition metal doped wide band semiconducting oxides. The
other oxide nanoparticles show somewhat lower values of magnetization but with
a clear hysteretic behavior. Conversely, the bulk samples obtained by sintering
the nanoparticles at high temperatures in air or oxygen became diamagnetic. As
there were no magnetic impurities present, we assume that the origin of
ferromagnetism may be due to the exchange interactions between localized
electron spin moments resulting from oxygen vacancies at the surfaces of
nanoparticles. We suggest that ferromagnetism may be a universal characteristic
of nanopartilces of metal oxides


title:
A Raman spectroscopic study of zircons on micro-scale and Its
  significance in explaining the origin of zircons

abstract:
  The magmatic and metamorphic zircons were investigated with Raman spectrum
microprobe analysis. We found notable differences between these two kinds of
zircons exhibited by the variation trend of Raman peak intensity from core to
rim of a crystal. In magmatic zircons, the intensity and the ratio H/W of Raman
spectrum peaks gradually decrease from core to rim of a crystal, which is
produced by an increase in metamictization degree and suggests an increase in U
and Th concentrations from core to rim. In metamorphic zircons, there are two
kinds of crystals according to their Raman spectra: the first group of zircons
exhibits a variation trend opposite to those of magmatic zircons, tending to
increase in the Raman peak intensity and H/W value from core to rim of a
crystal, which is produced by a decrease in metamictization degree and
indicates a decrease of U and Th concentrations from core to rim of a crystal.
The second group of zircons exhibits no change in Raman peak intensity and H/W
value through a crystal. The data of infrared and Raman spectra of these
crystals show that they are well crystallized and have no lattice destruction
induced by metamictization, and are thought to crystallize in high temperature
stages of metamorphism. During these stages, the U and Th ions have been
removed by metamorphic fluids from the parent rocks of these zircons. The other
difference between magmatic and metamorphic zircons is the background level of
their Raman spectra, which is high and sloped in magmatic zircons, but low and
horizontal in metamorphic zircons. The differences between magmatic and
metamorphic zircons can be used to identify the genesis of zircons and
understand the origin and evolution history of their parent rocks.


title: Random generation of finitely generated subgroups of a free group

abstract:
  We give an efficient algorithm to randomly generate finitely generated
subgroups of a given size, in a finite rank free group. Here, the size of a
subgroup is the number of vertices of its representation by a reduced graph
such as can be obtained by the method of Stallings foldings. Our algorithm
randomly generates a subgroup of a given size n, according to the uniform
distribution over size n subgroups. In the process, we give estimates of the
number of size n subgroups, of the average rank of size n subgroups, and of the
proportion of such subgroups that have finite index. Our algorithm has average
case complexity $\O(n)$ in the RAM model and $\O(n^2\log^2n)$ in the bitcost
model.


title:
Kinematic and stiffness analysis of the Orthoglide, a PKM with simple,
  regular workspace and homogeneous performances

abstract:
  The Orthoglide is a Delta-type PKM dedicated to 3-axis rapid machining
applications that was originally developed at IRCCyN in 2000-2001 to meet the
advantages of both serial 3-axis machines (regular workspace and homogeneous
performances) and parallel kinematic architectures (good dynamic performances
and stiffness). This machine has three fixed parallel linear joints that are
mounted orthogonally. The geometric parameters of the Orthoglide were defined
as function of the size of a prescribed cubic Cartesian workspace that is free
of singularities and internal collision. The interesting features of the
Orthoglide are a regular Cartesian workspace shape, uniform performances in all
directions and good compactness. In this paper, a new method is proposed to
analyze the stiffness of overconstrained Delta-type manipulators, such as the
Orthoglide. The Orthoglide is then benchmarked according to geometric,
kinematic and stiffness criteria: workspace to footprint ratio, velocity and
force transmission factors, sensitivity to geometric errors, torsional
stiffness and translational stiffness.


title:
The barnes G function and its relations with sums and products of
  generalized Gamma convolution variables

abstract:
  We give a probabilistic interpretation for the Barnes G-function which
appears in random matrix theory and in analytic number theory in the important
moments conjecture due to Keating-Snaith for the Riemann zeta function, via the
analogy with the characteristic polynomial of random unitary matrices. We show
that the Mellin transform of the characteristic polynomial of random unitary
matrices and the Barnes G-function are intimately related with products and
sums of gamma, beta and log-gamma variables. In particular, we show that the
law of the modulus of the characteristic polynomial of random unitary matrices
can be expressed with the help of products of gamma or beta variables, and that
the reciprocal of the Barnes G-function has a L\'{e}vy-Khintchin type
representation. These results lead us to introduce the so called generalized
gamma convolution variables.


title:
The cubic nonlinear Schr\"odinger equation in two dimensions with radial
  data

abstract:
  We establish global well-posedness and scattering for solutions to the
mass-critical nonlinear Schr\"odinger equation $iu_t + \Delta u = \pm |u|^2 u$
for large spherically symmetric L^2_x(\R^2) initial data; in the focusing case
we require, of course, that the mass is strictly less than that of the ground
state. As a consequence, we deduce that in the focusing case, any spherically
symmetric blowup solution must concentrate at least the mass of the ground
state at the blowup time.
  We also establish some partial results towards the analogous claims in other
dimensions and without the assumption of spherical symmetry.


title: Fusion Algebras of Logarithmic Minimal Models

abstract:
  We present explicit conjectures for the chiral fusion algebras of the
logarithmic minimal models LM(p,p') considering Virasoro representations with
no enlarged or extended symmetry algebra. The generators of fusion are
countably infinite in number but the ensuing fusion rules are quasi-rational in
the sense that the fusion of a finite number of representations decomposes into
a finite direct sum of representations. The fusion rules are commutative,
associative and exhibit an sl(2) structure but require so-called Kac
representations which are reducible yet indecomposable representations of rank
1. In particular, the identity of the fundamental fusion algebra is in general
a reducible yet indecomposable Kac representation of rank 1. We make detailed
comparisons of our fusion rules with the results of Gaberdiel and Kausch for
p=1 and with Eberle and Flohr for (p,p')=(2,5) corresponding to the logarithmic
Yang-Lee model. In the latter case, we confirm the appearance of indecomposable
representations of rank 3. We also find that closure of a fundamental fusion
algebra is achieved without the introduction of indecomposable representations
of rank higher than 3. The conjectured fusion rules are supported, within our
lattice approach, by extensive numerical studies of the associated integrable
lattice models. Details of our lattice findings and numerical results will be
presented elsewhere. The agreement of our fusion rules with the previous fusion
rules lends considerable support for the identification of the logarithmic
minimal models LM(p,p') with the augmented c_{p,p'} (minimal) models defined
algebraically.

categories: hep-th cond-mat.stat-mech math-ph math.MP


title:
Electromagnetism and perfect fluids interplay in multidimensional
  spacetimes

abstract:
  We consider fields in (D>2)-dimensional spacetime, whose potential is r-form
(skew-symmetric tensor of rank r), the field tensor F being its exterior
derivative and the Lagrangian, a function of the quadratic invariant I of this
tensor. It is shown that vector field (r=1) describes electromagnetic field
only for D=4. In particular, for D=3 and the Lagrangean L as any function of
the above-mentioned invariant, the (r=1)-field has energy-momentum tensor
identical with that of a perfect fluid whose equation of state depends on the
choice of L(I).


title: Toward Coupling Flow Driven and Magnetically Driven Dynamos

abstract:
  Most large scale dynamo research for astrophysical rotators focuses on
interior flow driven helical dynamos (FDHDs), but larger scale coronal fields
most directly influence observations. It is thus important to understand the
relationship between coronal and interior fields. Coronal field relaxation is
actually a type of magnetically dominated helical dynamo (MDHD). MDHDs also
occur in fusion plasma devices where they drive a system toward its relaxed
state in response to magnetic helicity injection that otherwise drives the
system away from this state. Global scale fields of astrophysical rotators and
jets are thus plausibly produced by a direct coupling between an interior FDHD
and a coronal MDHD, interfaced by magnetic helicity transport through their
mutual boundary. Tracking the magnetic helicity also elucidates how both FDHD
and MDHDs evolve and saturate. The utility of magnetic helicity is unhampered
by its non-gauge invariance since physical fields can always be recovered.


title: Zeeman-type dragging in the Kerr--Newman and NUT spacetimes

abstract:
  In this communication we discuss two distinct Zeeman-type gravitomagnetic
effects deserving attention since they can be easily characterized in their
exact form, not via approximation procedures. Some observations are also made
on gravitoelectric effects.


title:
Nariai--Bertotti--Robinson spacetimes as a building material for one-way
  wormholes with horizons, but without singularity

abstract:
  We discuss the problem of wormholes from the viewpoint of gluing together two
Reissner--Nordstr\"om-type universes while putting between them a segment of
the Nariai-type world (in both cases there are also present electromagnetic
fields as well as the cosmological constant). Such a toy wormhole represents an
example of one-way topological communication free from causal paradoxes, though
involving a travel to next spacetime sheet since one has to cross at least a
pair of horizons through which the spacetimes' junction occurs. We also
consider the use of thin shells in these constructions. Such a ``material'' for
wormholes we choose taking into account specific properties of the
Nariai--Bertotti--Robinson spacetimes.


title: T-odd asymmetries in radiative top-quark decays

abstract:
  We study the angular distribution of the charged lepton in the top-quark
decay into a bottom quark and a W boson which subsequently decays into
\ell\nu_{\ell}, when a hard gluon is radiated off. The absorptive part of the t
\to bWg decay amplitudes, which gives rise to T-odd asymmetries in the
distribution, is calculated at the one-loop level in perturbative QCD. The
asymmetries at a few percent level are predicted, which may be observable at
future colliders.


title: Galilean geometry of motions

abstract:
  In this paper we show that Galilean group is a matrix Lie group and find its
structure. Then provide the invariants of special Galilean geometry of motions,
by Olver's method of moving coframes, we also find the corresponding
$\{e\}-$structure.


title: Effect of Soft Modes on the Shear Viscosity of Quark Matter

abstract:
  We calculate shear viscosity of the quark matter at finite temperature and
density. If we assume that the quark interacts with the soft mode, which is a
collective mode of quark-antiquark pair, the self energy of the quark is
calculated by using the quasi-particle random phase approximation. It is shown
that its imaginary part is large and the mean free path of the quark is short.
With the use of the Kubo formula, the shear viscosity of quark matter becomes
small. The Reynolds number of the quark matter is estimated to be about $3\sim
30$. As the temperature increases, the shear viscosity increases gradually for
$T>200{\rm MeV}$. Moreover it is shown that the shear viscosity is not
sensitive to the chemical potential.


title:
Phase diagram for the one-dimensional Hubbard-Holstein model: A
  density-matrix renormalization group study

abstract:
  Phase diagram of the Hubbard-Holstein model in the coexistence of
electron-electron and electron-phonon interactions has been theoretically
obtained with the density-matrix renormalization group method for
one-dimensional (1D) systems, where an improved warm-up (the recursive sweep)
procedure has enabled us to calculate various correlation functions. We have
examined the cases of (i) the systems half-filled by electrons for the full
parameter space spanned by the electron-electron and electron-phonon coupling
constants and the phonon frequency, (ii) non-half-filled system, and (iii)
trestle lattice. For (i), we have detected a region where both the charge and
on-site pairing correlations decay with power-laws in real space, which
suggests a metallic behavior. While pairing correlations are not dominant in
(i), we have found that they become dominant as the system is doped in (ii), or
as the electronic band structure is modified (with a broken electron-hole
symmetry) in (iii) in certain parameter regions.


title: Growth-optimal portfolios under transaction costs

abstract:
  This paper studies a portfolio optimization problem in a discrete-time
Markovian model of a financial market, in which asset price dynamics depend on
an external process of economic factors. There are transaction costs with a
structure that covers, in particular, the case of fixed plus proportional
costs. We prove that there exists a self-financing trading strategy maximizing
the average growth rate of the portfolio wealth. We show that this strategy has
a Markovian form. Our result is obtained by large deviations estimates on
empirical measures of the price process and by a generalization of the
vanishing discount method to discontinuous transition operators.


title: Review of diffraction at HERA and Tevatron

abstract:
  We present and discuss the recent results on diffraction from the HERA and
Tevatron experiments.


title:
Enhancing single-molecule photostability by optical feedback from
  quantum-jump detection

abstract:
  We report an optical technique that yields an enhancement of single-molecule
photostability, by greatly suppressing photobleaching pathways which involve
photoexcitation from the triplet state. This is accomplished by dynamically
switching off the excitation laser when a quantum-jump of the molecule to the
triplet state is optically detected. This procedure leads to a lengthened
single-molecule observation time and an increased total number of detected
photons. The resulting improvement in photostability unambiguously confirms the
importance of photoexcitation from the triplet state in photobleaching
dynamics, and may allow the investigation of new phenomena at the
single-molecule level.


title:
Evidence for a breakdown of the Isobaric Multiplet Mass Equation: A
  study of the A=35, T=3/2 isospin quartet

abstract:
  Mass measurements on radionuclides along the potassium isotope chain have
been performed with the ISOLTRAP Penning trap mass spectrometer. For 35K
T1/2=178ms) to 46K (T1/2=105s) relative mass uncertainties of 2x10-8 and better
have been achieved. The accurate mass determination of 35K (dm=0.54keV) has
been exploited to test the Isobaric Multiplet Mass Equation (IMME) for the
A=35, T=3/2 isospinquartet. The experimental results indicate a deviation from
the generally adopted quadratic form.


title:
Stability in the instantaneous Bethe-Salpeter formalism:
  harmonic-oscillator reduced Salpeter equation

abstract:
  A popular three-dimensional reduction of the Bethe-Salpeter formalism for the
description of bound states in quantum field theory is the Salpeter equation,
derived by assuming both instantaneous interactions and free propagation of all
bound-state constituents. Numerical (variational) studies of the Salpeter
equation with confining interaction, however, observed specific instabilities
of the solutions, likely related to the Klein paradox and rendering (part of
the) bound states unstable. An analytic investigation of this problem by a
comprehensive spectral analysis is feasible for the reduced Salpeter equation
with only harmonic-oscillator confining interactions. There we are able to
prove rigorously that the bound-state solutions correspond to real discrete
energy spectra bounded from below and are thus free of any instabilities.


title: Geo-neutrinos and Earth's interior

abstract:
  The deepest hole that has ever been dug is about 12 km deep. Geochemists
analyze samples from the Earth's crust and from the top of the mantle.
Seismology can reconstruct the density profile throughout all Earth, but not
its composition. In this respect, our planet is mainly unexplored.
Geo-neutrinos, the antineutrinos from the progenies of U, Th and K40 decays in
the Earth, bring to the surface information from the whole planet, concerning
its content of natural radioactive elements. Their detection can shed light on
the sources of the terrestrial heat flow, on the present composition, and on
the origins of the Earth. Geo-neutrinos represent a new probe of our planet,
which can be exploited as a consequence of two fundamental advances that
occurred in the last few years: the development of extremely low background
neutrino detectors and the progress on understanding neutrino propagation. We
review the status and the prospects of the field.

categories: physics.geo-ph astro-ph hep-ph nucl-ex nucl-th


title: Emergence of the NMSGUT

abstract:
  We trace the emergence of the ``New Minimal'' supersymmetric SO(10) GUT
(NMSGUT) out of the debris created by our demonstration that the MSGUT is
falsified by the data. The NMSGUT is based on ${\bf{210\oplus 10\oplus
120\oplus 126\oplus {\bar {126}}}}$ Higgs system. It has only spontaneous CP
violation and Type I seesaw. With only 24 real superpotential parameters it is
the simplest model capable of accommodating the known 18 parameter fermion mass
data set and yet has enough freedom to accommodate the still unknown Leptonic
CP violation and neutrino mass scale parameters. Our focus is on the two most
salient features uncovered by our analysis: the domination of the
${\bf{\bar{126}}}$ Yukawa couplings by those of the ${\bf{10,120}}$ (required
for evasion of the no-go that trapped the MSGUT) and the inescapable raising of
the Baryon violation scales(and thus suppression of proton decay) decreed by a
proper inclusion of the threshold effects associated with the calculated
superheavy spectra. These two structural features are shown to be
complementary.


title: Neutrality and Many-Valued Logics

abstract:
  In this book, we consider various many-valued logics: standard, linear,
hyperbolic, parabolic, non-Archimedean, p-adic, interval, neutrosophic, etc. We
survey also results which show the tree different proof-theoretic frameworks
for many-valued logics, e.g. frameworks of the following deductive calculi:
Hilbert's style, sequent, and hypersequent. We present a general way that
allows to construct systematically analytic calculi for a large family of
non-Archimedean many-valued logics: hyperrational-valued, hyperreal-valued, and
p-adic valued logics characterized by a special format of semantics with an
appropriate rejection of Archimedes' axiom. These logics are built as different
extensions of standard many-valued logics (namely, Lukasiewicz's, Goedel's,
Product, and Post's logics). The informal sense of Archimedes' axiom is that
anything can be measured by a ruler. Also logical multiple-validity without
Archimedes' axiom consists in that the set of truth values is infinite and it
is not well-founded and well-ordered. On the base of non-Archimedean valued
logics, we construct non-Archimedean valued interval neutrosophic logic INL by
which we can describe neutrality phenomena.


title: A random walker on a ratchet potential: Effect of a non Gaussian noise

abstract:
  We analyze the effect of a colored non Gaussian noise on a model of a random
walker moving along a ratchet potential. Such a model was motivated by the
transport properties of motor proteins, like kinesin and myosin. Previous
studies have been realized assuming white noises. However, for real situations,
in general we could expect that those noises be correlated and non Gaussian.
Among other aspects, in addition to a maximum in the current as the noise
intensity is varied, we have also found another optimal value of the current
when departing from Gaussian behavior. We show the relevant effects that arise
when departing from Gaussian behavior, particularly related to current's
enhancement, and discuss its relevance for both biological and technological
situations.


title: Index theory for actions of compact Lie groups on C*-algebras

abstract:
  We study the index theory for actions of compact Lie groups on C*-algebras
with an emphasis on principal actions. Given an invariant semifinite trace on
the C*-algebra we obtain semifinite spectral triples. For circle actions we
consider the relation to the dual Pimsner-Voiculescu sequence. On the way we
show that the notions ``saturated'' and ``principal'' are equivalent for
actions by compact Lie groups.


title:
Amplification of gravitational waves signal in Michelson
  coherent-squeezed interferometer

abstract:
  Gravitational waves reaching a Michelson interferometer are expected to
induce a very small change in the length of its arms causing a phase shift
between them, but it is very difficult to observe the extremely small phase
shift signals produced. In the present letter we show that the gravitational
waves signal could be amplified by orders of magnitude by using very special
conditions for a coherent-squeezed Michelson interferometer in which the
coherent state enters one port of the interferometer and the squeezed vacuum
enters in the other port. We treat the case where without the gravitational
induced phase shift the very strong coherent state goes out of one output port
while the squeezed vacuum goes out the other output port (the ``dark'' port).
While the phase shift produced by the gravitation waves does not give any
significant change in the strong coherent output, the light intensity in the
``dark'' port is amplified with decreased fluctuations as the squeezing
increases.


title:
Commensurability effects for fermionic atoms trapped in 1D optical
  lattices

abstract:
  Fermionic atoms in two different hyperfine states confined in optical
lattices show strong commensurability effects due to the interplay between the
atomic density wave (ADW) ordering and the lattice potential. We show that
spatially separated regions of commensurable and incommensurable phases can
coexist. The commensurability between the harmonic trap and the lattice sites
can be used to control the amplitude of the atomic density waves in the central
region of the trap.


title:
Applications of the change-of-rings spectral sequence to the computation
  of Hochschild cohomology

abstract:
  We consider the change-of-rings spectral sequence as it applies to Hochschild
cohomology, obtaining a description of the differentials on the first page
which relates it to the multiplicative stucture on cohomology. Using this
information, we are able to completely describe the cohomology structure of
monogenic algebras as well as some information on the structure of the
cohomology in more general situations.
  We also show how to use the spectral sequence to reprove and generalize
results of M. Auslander et. al. about homological epimorphisms. We derive from
this a rather general version of the long exact sequence due to D. Happel for a
one-point (co)-extension of a finite dimensional algebra and show how it can be
put to use in concrete examples.


title:
Asymptotic behavior and orbital stability of galactic dynamics in
  relativistic scalar gravity

abstract:
  The Nordstr\"om-Vlasov system is a relativistic Lorentz invariant
generalization of the Vlasov-Poisson system in the gravitational case. The
asymptotic behavior of solutions and the non-linear stability of steady states
are investigated. It is shown that solutions of the Nordstr\"om-Vlasov system
with energy grater or equal to the mass satisfy a dispersion estimate in terms
of the conformal energy. When the energy is smaller than the mass, we prove
existence and non-linear (orbital) stability of a class of static solutions
(isotropic polytropes) against general perturbations. The proof of orbital
stability is based on a variational problem associated to the minimization of
the energy functional under suitable constraints.


title:
Signature of chirality in scanning-probe imaging of charge flow in
  graphene

abstract:
  We theoretically propose to directly observe the chiral nature of charge
carriers in graphene mono- and bilayers within a controlled scattering
experiment. The charge located on a capacitively coupled scanning probe
microscope (SPM) tip acts as a scattering center with controllable position on
the graphene sheet. Unambiguous features from the chirality of the particles in
single and bilayer graphene arise in the ballistic transport in the presence of
such a scattering center. To theoretically model the scattering from the smooth
potential created by the SPM tip, we develop the scattering formalism within
first-order Born approximation. We calculate the current through a device with
an SPM tip between two constrictions (quantum point contacts) as a function of
the tip position.


title:
Demonstration of Temporal Distinguishability of Three and Four Photons
  with Asymmetric Beam Splitter

abstract:
  By using an asymmetric beam splitter, we observe the generalized
Hong-Ou-Mandel effects for three and four photons, respectively. Furthermore,
we can use this generalized Hong-Ou-Mandel interferometer to characterize
temporal distinguishability.


title:
The quantum solvation, adiabatic versus nonadiabatic, and Markovian
  versus non-Markovian nature of electron transfer rate processes

abstract:
  In this work, we revisit the electron transfer rate theory, with particular
interests in the distinct quantum solvation effect, and the characterizations
of adiabatic/nonadiabatic and Markovian/non-Markovian rate processes. We first
present a full account for the quantum solvation effect on the electron
transfer in Debye solvents, addressed previously in J. Theore. & Comput. Chem.
{\bf 5}, 685 (2006). Distinct reaction mechanisms, including the quantum
solvation-induced transitions from barrier-crossing to tunneling, and from
barrierless to quantum barrier-crossing rate processes, are shown in the fast
modulation or low viscosity regime. This regime is also found in favor of
nonadiabatic rate processes. We further propose to use Kubo's motional
narrowing line shape function to describe the Markovian character of the
reaction. It is found that a non-Markovian rate process is most likely to occur
in a symmetric system in the fast modulation regime, where the electron
transfer is dominant by tunneling due to the Fermi resonance.


title: Many-Body Separability of Warm Qubits

abstract:
  We analyze the separability of the joint state of a collection of two-level
systems at finite temperature T. The fact that only separable states are found
in the neighborhood of their thermal equilibrium state guarantees that
decoherence will destroy any initially arranged entanglement in a finite time.


title: Complex cobordism and algebraic topology

abstract: This is a historical survey, beginning where Atiyah and Sullivan leave off...


title: Soft ideals and arithmetic mean ideals

abstract:
  This article investigates the soft-interior and the soft-cover of operator
ideals. These operations, and especially the first one, have been widely used
before, but making their role explicit and analyzing their interplay with the
arithmetic mean operations is essential for the study of the multiplicity of
traces (see arXiv:0707.3169v1 [math.FA]). Many classical ideals are "soft",
i.e., coincide with their soft interior or with their soft cover, and many
ideal constructions yield soft ideals. Arithmetic mean (am) operations were
proven to be intrinsic to the theory of operator ideals by the work of Dykema,
Figiel, Weiss, and Wodzicki on the structure of commutators and arithmetic mean
operations at infinity were studied in arXiv:0707.3169v1 [math.FA]. Here we
focus on the commutation relations between these operations and soft
operations. In the process we characterize the am-interior and the am-infinity
interior of an ideal.


title: Satellite Luminosities in Galaxy Groups

abstract:
  Halo model interpretations of the luminosity dependence of galaxy clustering
assume that there is a central galaxy in every sufficiently massive halo, and
that this central galaxy is very different from all the others in the halo. The
halo model decomposition makes the remarkable prediction that the mean
luminosity of the non-central galaxies in a halo should be almost independent
of halo mass: the predicted increase is about 20% while the halo mass increases
by a factor of more than 20. In contrast, the luminosity of the central object
is predicted to increase approximately linearly with halo mass at low to
intermediate masses, and logarithmically at high masses. We show that this
weak, almost non-existent mass-dependence of the satellites is in excellent
agreement with the satellite population in group catalogs constructed by two
different collaborations. This is remarkable, because the halo model prediction
was made without ever identifying groups and clusters. The halo model also
predicts that the number of satellites in a halo is drawn from a Poisson
distribution with mean which depends on halo mass. This, combined with the weak
dependence of satellite luminosity on halo mass, suggests that the Scott
effect, such that the luminosities of very bright galaxies are merely the
statistically extreme values of a general luminosity distribution, may better
apply to the most luminous satellite galaxy in a halo than to BCGs. If galaxies
are identified with halo substructure at the present time, then central
galaxies should be about 4 times more massive than satellite galaxies of the
same luminosity, whereas the differences between the stellar M/L ratios should
be smaller. Therefore, a comparison of the weak lensing signal from central and
satellite galaxies should provide useful constraints. [abridged]


title: Unitarity and real properties of the neutral meson complex

abstract:
  The proof of the Khalfin Theorem for neutral meson complex is analyzed. It is
shown that the unitarity of the time evolution operator for the total system
under considerations assures that the Khalfin's Theorem holds. The consequences
of this Theorem for the neutral mesons system are discussed: it is shown, eg.,
that diagonal matrix elements of the exact effective Hamiltonian for the
neutral meson complex can not be equal if CPT symmetry holds and CP symmetry is
violated. Properties of time evolution governed by a time--independent
effective Hamiltonian acting in the neutral mesons subspace of states are
considered. Using the Khalfin's Theorem it is shown that if such Hamiltonian is
time--independent then the evolution operator for the total system containing
the neutral meson complex can not be a unitary operator. It is shown
graphically for a given specific model how the Khalfin's Theorem works. It is
also shown for this model how the difference of the mentioned diagonal matrix
elements of the effective Hamiltonian varies in time.


title:
First-principles modeling of BaCeO_{3}: structure and stabilization of O
  vacancies by Pd-doping

abstract:
  We use first-principles density functional theory (DFT) calculations to
investigate the ground state structures of both BaCeO_{3} (BC) and Pd-doped BC
(BCP). The relaxed structures match closely with recent experimental scattering
studies, and also provide a local picture of how the BC perovskite lattice
accommodates Pd. Both stoichiometric and oxygen-deficient materials are
considered, and structures with an O vacancy adjacent to each Pd are predicted
to be favored. The oxidation state of Pd in each doped structure is
investigated through a structural analysis, the results of which are supported
by an orbital-resolved projected density of states. The vacancy stabilization
by Pd in BCP is explained through redox chemistry and lattice strain relief.


title:
Continuous Time Random Walks (CTRWs): Simulation of continuous
  trajectories

abstract:
  Continuous time random walks have been developed as a straightforward
generalisation of classical random walk processes. Some 10 years ago, Fogedby
introduced a continuous representation of these processes by means of a set of
Langevin equations [H. C. Fogedby, Phys. Rev. E 50 (1994)]. The present work is
devoted to a detailed discussion of Fogedby's model and presents its
application for the robust numerical generation of sample paths of continuous
time random walk processes.


title: When is g_{tt} g_{rr} = -1?

abstract:
  The Schwarzschild metric, its Reissner-Nordstrom-de Sitter generalizations to
higher dimensions, and some further generalizations all share the feature that
g_{tt} g_{rr}=-1 in Schwarzschild-like coordinates. In this pedagogical note we
trace this feature to the condition that the Ricci tensor (and stress-energy
tensor in a solution to Einstein's equation) has vanishing radial null-null
component, i.e. is proportional to the metric in the t-r subspace. We also show
this condition holds if and only if the area-radius coordinate is an affine
parameter on the radial null geodesics.


title:
The Circumstellar Structure and Excitation Effects around the Massive
  Protostar Cepheus A HW 2

abstract:
  We report SMA 335 GHz continuum observations with angular resolution of
~0.''3, together with VLA ammonia observations with ~1'' resolution toward Cep
A HW 2. We find that the flattened disk structure of the dust emission observed
by Patel et al. is preserved at the 0.''3 scale, showing an elongated structure
of ~$0.''6 size (450 AU) peaking on HW 2. In addition, two ammonia cores are
observed, one associated with a hot-core previously reported, and an elongated
core with a double peak separated by ~1.''3 and with signs of heating at the
inner edges of the gas facing HW 2. The double-peaked ammonia structure, as
well as the double-peaked CH3CN structure reported previously (and proposed to
be two independent hot-cores), surround both the dust emission as well as the
double-peaked SO2 disk structure found by Jimenez-Serra et al. All these
results argue against the interpretation of the elongated dust-gas structure as
due to a chance-superposition of different cores; instead, they imply that it
is physically related to the central massive object within a disk-protostar-jet
system.


title: Tight-binding modeling of charge migration in DNA devices

abstract:
  Long range charge transfer experiments in DNA oligomers and the subsequently
measured -- and very diverse -- transport response of DNA wires in solid state
experiments exemplifies the need for a thorough theoretical understanding of
charge migration in DNA-based natural and artificial materials. Here we present
a review of tight-binding models for DNA conduction which have the intrinsic
merit of containing more structural information than plain rate-equation models
while still retaining sufficient detail of the electronic properties. This
allows for simulations of transport properties to be more manageable with
respect to density functional theory methods or correlated first principle
algorithms.


title: Gluon contributions to the pion mass and light cone momentum fraction

abstract:
  We calculate the matrix elements of the gluonic contributions to the
energy-momentum tensor for a pion of mass 600 < Mpi < 1100 MeV in quenched
lattice QCD. We find that gluons contribute (37 +/- 8 +/- 12)% of the pion's
light cone momentum. The bare matrix elements corresponding to the trace
anomaly contribution to the pion mass are also obtained. The discretizations of
the energy-momentum tensor we use have other promising applications, ranging
from calculating the origin of hadron spin to QCD thermodynamics.


title: Invariants of Closed 3-Manifolds via Nullhomotopic Filling Dehn Spheres

abstract:
  We provide a calculus for the presentation of closed 3-manifolds via
nullhomotopic filling Dehn spheres and we use it to define an invariant of
closed 3-manifolds by applying the state-sum machinery. As a potential
application of this invariant, we show how to get lower bounds for the Matveev
complexity of P2-irreducible closed 3-manifolds. We also describe an easy
algorithm for constructing a nullhomotopic filling Dehn sphere of each closed
3-manifold from any of its one-vertex triangulations.


title:
Direct and reverse log-Sobolev inequalities in $\mu$-deformed
  Segal-Bargmann analysis

abstract:
  Both direct and reverse log-Sobolev inequalities, relating the Shannon
entropy with a $\mu$-deformed energy, are shown to hold in a family of
$\mu$-deformed Segal-Bargmann spaces. This shows that the $\mu$-deformed energy
of a state is finite if and only if its Shannon entropy is finite. The direct
inequality is a new result, while the reverse inequality has already been shown
by the authors but using different methods. Next the $\mu$-deformed energy of a
state is shown to be finite if and only if its Dirichlet form energy is finite.
This leads to both direct and reverse log-Sobolev inequalities that relate the
Shannon entropy with the Dirichlet energy. We obtain that the Dirichlet energy
of a state is finite if and only if its Shannon entropy is finite. The main
method used here is based on a study of the reproducing kernel function of
these spaces and the associated integral kernel transform.


title:
1- Brane Sources for the Lightcone Worldsheet: Q-branion - {\bar
  Q}-branion Scattering to One Loop

abstract:
  This paper extends the study, initiated by Rozowsky and Thorn [1], of gauge
fields in interaction with Dirac fields living on separated parallel 1-branes.
In a lightcone description, replacing static point sources by 1-brane sources
allows p^+ conservation to be maintained in their presence, which simplifies
the lightcone quantization procedure. Here we calculate on-shell branion
scattering amplitudes through 1 loop in lightcone gauge, and thereby resolve a
puzzling ambiguity encountered in the off-shell calculations of [1]. We confirm
that infrared divergences cancel in properly defined scattering probabilities.
This work lays the groundwork for the incorporation of 1-brane sources in the
lightcone worldsheet formalism.


title: Leibniz seminorms for "Matrix algebras converge to the sphere"

abstract:
  In an earlier paper of mine relating vector bundles and Gromov-Hausdorff
distance for ordinary compact metric spaces, it was crucial that the Lipschitz
seminorms from the metrics satisfy a strong Leibniz property. In the present
paper, for the now non-commutative situation of matrix algebras converging to
the sphere (or to other spaces) for quantum Gromov-Hausdorff distance, we show
how to construct suitable seminorms that also satisfy the strong Leibniz
property. This is in preparation for making precise certain statements in the
literature of high-energy physics concerning "vector bundles" over matrix
algebras that "correspond" to monopole bundles over the sphere. We show that a
fairly general source of seminorms that satisfy the strong Leibniz property
consists of derivations into normed bimodules. For matrix algebras our main
technical tools are coherent states and Berezin symbols.


title: Is WMAP3 normalization compatible with the X-Ray cluster abundance?

abstract:
  We present the mass and X-ray temperature functions derived from a sample of
more than 15,000 galaxy clusters of the MareNostrum Universe cosmological SPH
simulations. In these simulations, we follow structure formation in a cubic
volume of 500/h Mpc on a side assuming cosmological parameters consistent with
either the first or third year WMAP data and gaussian initial conditions. We
compare our numerical predictions with the most recent observational estimates
of the cluster X-ray temperature functions and find that the low normalization
cosmological model inferred from the 3 year WMAP data results is barely
compatible with the present epoch X-ray cluster abundances. We can only
reconcile the simulations with the observational data if we assume a
normalization of the Mass-Temperature relation which is a factor of 2.5--3
smaller than our non-radiative simulations predict. This deviation seems to be
too large to be accounted by the effects of star formation or cooling in the
ICM, not taken into account in these simulations.


title: Estimation of Small s-t Reliabilities in Acyclic Networks

abstract:
  In the classical s-t network reliability problem a fixed network G is given
including two designated vertices s and t (called terminals). The edges are
subject to independent random failure, and the task is to compute the
probability that s and t are connected in the resulting network, which is known
to be #P-complete. In this paper we are interested in approximating the s-t
reliability in case of a directed acyclic original network G. We introduce and
analyze a specialized version of the Monte-Carlo algorithm given by Karp and
Luby. For the case of uniform edge failure probabilities, we give a worst-case
bound on the number of samples that have to be drawn to obtain an epsilon-delta
approximation, being sharper than the original upper bound. We also derive a
variance reduction of the estimator which reduces the expected number of
iterations to perform to achieve the desired accuracy when applied in
conjunction with different stopping rules. Initial computational results on two
types of random networks (directed acyclic Delaunay graphs and a slightly
modified version of a classical random graph) with up to one million vertices
are presented. These results show the advantage of the introduced Monte-Carlo
approach compared to direct simulation when small reliabilities have to be
estimated and demonstrate its applicability on large-scale instances.


title:
Comparison between the Blue and the Red Galaxy Alignments Detected in
  the Sloan Digital Sky Survey

abstract:
  We measure the intrinsic alignments of the blue and the red galaxies
separately by analyzing the spectroscopic data of the Sloan Digital Sky Survey
Data Release 6 (SDSS DR6). For both samples of the red and the blue galaxies
with axial ratios of b/a <= 0.8, we detect a 3 sigma signal of the ellipticity
correlation in the redshift range of 0 <= z <= 0.4 for r-band absolute (model)
magnitude cut of M_r <= -19.2 (no K correction). We note a difference in the
strength and the distance scale for the red and the blue galaxy correlation
eta_{2D}(r): For the bright blue galaxies, it behaves as a quadratic scaling of
the linear density correlation of xi(r) as eta_{2D}(r) proportional to
xi^{2}(r) with strong signal detected only at small distance bin of r <= 3
Mpc/h. While for the bright red galaxies it follows a linear scaling as
eta_{2D}(r) proportional to xi(r) with signals detected at larger distance out
to r~6 Mpc/h. We also test whether the detected correlation signal is intrinsic
or spurious by quantifying the systematic error and find that the effect of the
systematic error on the ellipticity correlation is negligible. It is finally
concluded that our results will be useful for the weak lensing measurements as
well as the understanding of the large scale structure formation.


title:
Measure-valued equations for Kolmogorov operators with unbounded
  coefficients

abstract:
  Given a real and separable Hilbert space H we consider the measure-valued
equation \begin{equation*} \int_H\phi(x)\mu_t(dx)- \int_H\phi(x)\mu(dx)=
  \int_0^t(\int_HK_0\phi(x)\mu_s(dx))ds, \end{equation*} where K_0 is the
Kolmogorov differential operator \[
  K_0\phi(x)=\frac12\textrm{Trace}\big[BB^*D^2\phi(x)\big]+< x,A^*D\phi(x)>+<
D\phi(x),F(x)>, \] $x\in H$, $\phi:H\to \Rset$ is a suitable smooth function,
$A:D(A)\subset H\to H $ is linear, $F:H\to H$ is a globally Lipschitz function
and $B:H\to H$ is linear and continuous. In order prove existence and
uniqueness of a solution for the above equation, we show that $K_0$ is a core,
in a suitable way, of the infinitesimal generator associated to the solution of
a certain stochastic differential equation in H.
  We also extend the above results to a reaction-diffusion operator with
polinomial nonlinearities.