title: Fluctuation bounds for the asymmetric simple exclusion process

abstract:
  We give a partly new proof of the fluctuation bounds for the second class
particle and current in the stationary asymmetric simple exclusion process. One
novelty is a coupling that preserves the ordering of second class particles in
two systems that are themselves ordered coordinatewise.


title: Adaptive Multi-Dimensional Particle In Cell

abstract:
  Kinetic Particle In Cell (PIC) methods can extend greatly their range of
applicability if implicit time differencing and spatial adaption are used to
address the wide range of time and length scales typical of plasmas. For
implicit differencing, we refer the reader to our recent summary of the
implicit moment PIC method implemented in our CELESTE3D code [G. Lapenta, Phys.
Plasmas, 13, 055904 (2006)]. Instead, the present document deals with the issue
of PIC spatial adaptation. Adapting a kinetic PIC code requires two tasks:
adapting the grid description of the fields and moments and adapting the
particle description of the distribution function. Below we address both
issues. First, we describe how grid adaptation can be guided by appropriate
measures of the local accuracy of the solution. Based on such information, grid
adaptation can be obtained by moving grid points from regions of lesser
interest to regions of higher interest or by adding and removing points. We
discuss both strategies. Second, we describe how to adapt the local number of
particles to reach the required statistical variance in the description of the
particle population. Finally two typical applications of adaptive PIC are
shown: collisionless shocks and charging of small bodies immersed in a plasma.


title:
Note: Axiomatic Derivation of the Doppler Factor and Related
  Relativistic Laws

abstract:
  The formula for the relativistic Doppler effect is investigated in the
context of two compelling invariance axioms. The axioms are expressed in terms
of an abstract operation generalizing the relativistic addition of velocities.
We prove the following results. (1) If the standard representation for the
operation is not assumed a priori, then each of the two axioms is consistent
with both the relativistic Doppler effect formula and the Lorentz-Fitzgerald
Contraction. (2) If the standard representation for the operation is assumed,
then the two axioms are equivalent to each other and to the relativistic
Doppler effect formula. Thus, the axioms are inconsistent with the
Lorentz-FitzGerald Contraction in this case. (3) If the Lorentz-FitzGerald
Contraction is assumed, then the two axioms are equivalent to each other and to
a different mathematical representation for the operation which applies in the
case of perpendicular motions. The relativistic Doppler effect is derived up to
one positive exponent parameter (replacing the square root). We prove these
facts under regularity and other reasonable background conditions.


title:
A generalization of Watts's Theorem: Right exact functors on module
  categories

abstract:
  Watts's Theorem says that a right exact functor F:Mod R-->Mod S that commutes
with direct sums is isomorphic to -\otimes_R B where B is the R-S-bimodule FR.
The main result in this paper is the following: if A is a cocomplete abelian
category and F:Mod R --> A is a right exact functor commuting with direct sums,
then F is isomorphic to - \otimes_R B where B is a suitable R-module in A,
i.e., a pair (B,f) consisting of an object B in A and a ring homomorphism f:R
--> Hom_A(B,B). Part of the point is to give meaning to the notation -\otimes_R
B. That is done in the paper by Artin and Zhang on Abstract Hilbert Schemes.
The present paper is a natural extension of some of the ideas in the first part
of their paper.


title:
Valence band and core level photoemission spectros-copy of
  LaFeAsO$_{1-x}$F$_{x}$

abstract:
  We have investigated the electronic structure of LaFeAsO$_{1-x}$F$_{x}$ (x =
0; 0.1; 0.2) by angle-integrated photoemission spectroscopy and local density
approximation (LDA) based band structure calculations. The valence band
consists of a low energy peak at E = -0.25 eV and a broad structure around E =
-5 eV in qualitative agreement with LDA. From the photon energy dependence of
these peaks we conclude that the former derives almost exclusively from Fe 3d
states. This constitutes experimental evidence for the strong iron character of
the relevant states in a broad window around EF and confirms theoretical
predictions.


title:
Quasimaps, straightening laws, and quantum cohomology for the Lagrangian
  Grassmannian

abstract:
  The Drinfel'd Lagrangian Grassmannian compactifies the space of algebraic
maps of fixed degree from the projective line into the Lagrangian Grassmannian.
It has a natural projective embedding arising from the canonical embedding of
the Lagrangian Grassmannian. We show that the defining ideal of any Schubert
subvariety of the Drinfel'd Lagrangian Grassmannian is generated by polynomials
which give a straightening law on an ordered set. Consequentially, any such
subvariety is Cohen-Macaulay and Koszul. The Hilbert function is computed from
the straightening law, leading to a new derivation of certain intersection
numbers in the quantum cohomology ring of the Lagrangian Grassmannian.


title: Pressure-induced polarization reversal in multiferroic $YMn_2O_5$

abstract:
  The low-temperature ferroelectric polarization of multiferroic $YMn_2O_5$ is
completely reversed at a critical pressure of 10 kbar and the phase transition
from the incommensurate to the commensurate magnetic phase is induced by
pressures above 14 kbar. The high-pressure data correlate with thermal
expansion measurements indicating a significant lattice strain at the
low-temperature transition into the incommensurate phase. The results support
the exchange striction model for the ferroelectricity in multiferroic
$RMn_2O_5$ compounds and they show the importance of magnetic frustration as
well as the spin-lattice coupling.


title: $p$-adic Hurwitz numbers

abstract:
  We introduce stable tropical curves and use these to count covers of the
$p$-adic projective line of fixed degree and ramification types by Mumford
curves in terms of tropical Hurwitz numbers. Our counts depend on the branch
loci of the covers.


title: Upper and Lower Bounds on Black-Box Steganography

abstract:
  We study the limitations of steganography when the sender is not using any
properties of the underlying channel beyond its entropy and the ability to
sample from it. On the negative side, we show that the number of samples the
sender must obtain from the channel is exponential in the rate of the
stegosystem. On the positive side, we present the first secret-key stegosystem
that essentially matches this lower bound regardless of the entropy of the
underlying channel. Furthermore, for high-entropy channels, we present the
first secret-key stegosystem that matches this lower bound statelessly (i.e.,
without requiring synchronized state between sender and receiver).


title: Performance Analysis of Multiple Antenna Multi-User Detection

abstract:
  We derive the diversity order of some multiple antenna multi-user
cancellation and detection schemes. The common property of these detection
methods is the usage of Alamouti and quasi-orthogonal space-time block codes.
For detecting $J$ users each having $N$ transmit antennas, these schemes
require only $J$ antennas at the receiver. Our analysis shows that when having
$M$ receive antennas, the array-processing schemes provide the diversity order
of $N(M-J+1)$. In addition, our results prove that regardless of the number of
users or receive antennas, when using maximum-likelihood decoding we get the
full transmit and receive diversities, i.e. $NM$, similar to the
no-interference scenario.


title: Hypersharp Resonant Capture of Anti-Neutrinos

abstract:
  Recent ideas suggest that the 18.6 keV antineutrino (nuebar) line from 2-body
decay of 3H in crystals is emitted with natural width, motionally narrowed by
lattice vibrations as in recoilless emission. It can be resonantly captured in
3He with geometrical cross section sigma ~10 ^ -17 cm2. A key technique solves
a basic obstacle for achieving resonance--the chemical difference of H and He
in metals. The low nue energy, the high sigma and the hypersharp sensitivity
DELTA E/E ~10^--29 make an extraordinary tool for bench scale tests of nue
theta13 oscillations and predicted Planck length limits on nuclear level widths
in models of quantum gravity.


title:
A Dynamic Programming Framework for Combinatorial Optimization Problems
  on Graphs with Bounded Pathwidth

abstract:
  In this paper we present an algorithmic framework for solving a class of
combinatorial optimization problems on graphs with bounded pathwidth. The
problems are NP-hard in general, but solvable in linear time on this type of
graphs. The problems are relevant for assessing network reliability and
improving the network's performance and fault tolerance. The main technique
considered in this paper is dynamic programming.


title: Is leptogenesis falsifiable at LHC?

abstract:
  It is well known that the leptogenesis mechanism offers an attractive
possibility to explain the baryon asymmetry of the universe. Its particular
robustness however comes with one major difficulty: it will be very hard if not
impossible to test experimentally in a foreseeable future, as most of the
mechanics typically takes place at high energy or results from suppressed
interactions, without unavoidable low-energy implications. An alternate
approach is taken by asking: can it be at least falsified? We show that
possible discoveries at current and future colliders, most notably that of
right-handed gauge interactions, would indeed forbid at least the "canonical"
leptogenesis mechanisms, namely those based on right-handed neutrino decay.
General lower bounds for successful leptogenesis on the mass of the
right-handed gauge boson W_R are given. Other possibilities to falsify
leptogenesis, including from the observation of a Z', are also considered.


title:
Local Ordering Of Polymer-Tethered Nanospheres And Nanorods And The
  Stabilization Of The Double Gyroid Phase

abstract:
  We present results of Brownian dynamics simulations of tethered nanospheres
and tethered nanorods. Immiscibility between tether and nanoparticle
facilitates microphase separation into the bicontinuous, double gyroid
structure (first reported by Iacovella et al. [Phys. Rev. E 75 (2007)] and
Horsch et al. [J. Chem. Phys. 125 (2006)] respectively). We demonstrate the
ability of these nanoparticles to adopt distinct, minimal energy local
packings, in which nanospheres form icosahedral-like clusters and nanorods form
splayed hexagonal bundles. These local structures reduce packing frustration
within the nodes of the double gyroid. We argue that the ability to locally
order into stable structures is key to the formation of the double gyroid phase
in these systems.


title:
The VLA Survey of the Chandra Deep Field South: I. Overview of the Radio
  Data

abstract:
  We report 20 and 6 cm VLA deep observations of the CDF-S including the
Extended CDF-S. We discuss the radio properties of 266 cataloged radio sources,
of which 198 are above a 20 cm completeness level reaching down to 43 microJy
at the center of the field. Survey observations made at 6 cm over a more
limited region covers the original CDF-S to a comparable level of sensitivity
as the 20 cm observations.
  Of 266 cataloged radio sources, 52 have X-ray counterparts in the CDF-S and a
further 37 in the E-CDF-S area not covered by the 1 Megasecond exposure. Using
a wide range of material, we have found optical or infrared counterparts for
254 radio sources, of which 186 have either spectroscopic or photometric
redshifts (Paper II). Three radio sources have no apparent counterpart at any
other wavelength. Measurements of the 20 cm radio flux density at the position
of each CDF-S X-ray source detected a further 30 radio sources above a
conservative 3-sigma detection limit.
  X-ray and sub-mm observations have been traditionally used as a measure of
AGN and star formation activity, respectively. These new observations probe the
faint end of both the star formation and radio galaxy/AGN population, as well
as the connection between the formation and evolution of stars and SMBHs. Both
of the corresponding gravitational and nuclear fusion driven energy sources can
lead to radio synchrotron emission. AGN and radio galaxies dominate at high
flux densities. Although emission from star formation becomes more prominent at
the microjansky levels reached by deep radio surveys, even for the weakest
sources, we still find an apparent significant contribution from low luminosity
AGN as well as from star formation.


title:
Electric displacement as the fundamental variable in
  electronic-structure calculations

abstract:
  Finite-field calculations in periodic insulators are technically and
conceptually challenging, due to fundamental problems in defining polarization
in extended solids. While significant progress has been made recently with the
establishment of techniques to fix the electric field E or the macroscopic
polarization P in first-principles calculations, both methods lack the ease of
use and conceptual clarity of standard zero-field calculations. Here we develop
a new formalism in which the electric displacement D, rather than E or P, is
the fundamental electrical variable. Fixing D has the intuitive interpretation
of imposing open-circuit electrical boundary conditions, which is particularly
useful in studying ferroelectric systems. Furthermore, the analogy to
open-circuit capacitors suggests an appealing reformulation in terms of free
charges and potentials, which dramatically simplifies the treatment of stresses
and strains. Using PbTiO3 as an example, we show that our technique allows full
control over the electrical variables within the density functional formalism.


title: Black hole mimickers: regular versus singular behavior

abstract:
  Black hole mimickers are possible alternatives to black holes, they would
look observationally almost like black holes but would have no horizon. The
properties in the near-horizon region where gravity is strong can be quite
different for both type of objects, but at infinity it could be difficult to
discern black holes from their mimickers. To disentangle this possible
confusion, we examine the near-horizon properties, and their connection with
far away properties, of some candidates to black mimickers. We study
spherically symmetric uncharged or charged but non-extremal objects, as well as
spherically symmetric charged extremal objects. Within the uncharged or charged
but non-extremal black hole mimickers, we study non-extremal
$\epsilon$-wormholes on the threshold of the formation of an event horizon, of
which a subclass are called black foils, and gravastars. Within the charged
extremal black hole mimickers we study extremal $\epsilon$-wormholes on the
threshold of the formation of an event horizon, quasi-black holes, and
wormholes on the basis of quasi-black holes from Bonnor stars. We elucidate,
whether or not the objects belonging to these two classes remain regular in the
near-horizon limit. The requirement of full regularity, i.e., finite curvature
and absence of naked behavior, up to an arbitrary neighborhood of the
gravitational radius of the object enables one to rule out potential mimickers
in most of the cases. A list ranking the best mimickers up to the worse is
given. Since, in observational astrophysics it is difficult to find extremal
configurations (the best mimickers in the ranking), whereas non-extremal
configurations are really bad mimickers, the task of distinguishing black holes
from their mimickers seems to be less difficult than one could think of.


title: Dynamics in the quantum Hall effect and the phase diagram of graphene

abstract:
  The dynamics responsible for lifting the degeneracy of the Landau levels in
the quantum Hall (QH) effect in graphene is studied by utilizing a low-energy
effective model with a contact interaction. A detailed analysis of the
solutions of the gap equation for Dirac quasiparticles is performed at both
zero and nonzero temperatures. The characteristic feature of the solutions is
that the order parameters connected with the QH ferromagnetism and magnetic
catalysis scenarios necessarily coexist. The solutions reproduce correctly the
experimentally observed novel QH plateaus in graphene in strong magnetic
fields. The phase diagram of this system in the plane of temperature and
electron chemical potential is analyzed. The phase transitions corresponding to
the transitions between different QH plateaus in graphene are described.


title:
Light CP-odd Higgs and Small $\tan \beta$ Scenario in the MSSM and
  Beyond

abstract:
  We study the Higgs sector of supersymmetric models containing two Higgs
doublets with a light MSSM-like CP odd Higgs, $m_A \lesssim 10$ GeV, and $\tan
\beta \lesssim 2.5$. In this scenario all of the Higgses resulting from two
Higgs doublets: light and heavy CP even Higgses, $h$ and $H$, the CP odd Higgs,
$A$, and the charged Higgs, $H^\pm$, could have been produced at LEP or the
Tevatron, but would have escaped detection because they decay in modes that
have not been searched for or the experiments are not sensitive to. Especially
$H \to ZA$ and $H^\pm \to W^{\pm \star} A$ with $A \to c \bar c, \tau^+ \tau^-$
present an opportunity to discover some of the Higgses at LEP, the Tevatron and
also at B factories. Typical $\tau$- and $c$-rich decay products of all Higgses
require modified strategies for their discovery at the LHC.


title: Top-tagging: A Method for Identifying Boosted Hadronic Tops

abstract:
  A method is introduced for distinguishing top jets (boosted, hadronically
decaying top quarks) from light quark and gluon jets using jet substructure.
The procedure involves parsing the jet cluster to resolve its subjets, and then
imposing kinematic constraints. With this method, light quark or gluon jets
with pT ~ 1 TeV can be rejected with an efficiency of around 99% while
retaining up to 40% of top jets. This reduces the dijet background to heavy
t-tbar resonances by a factor of ~10,000, thereby allowing resonance searches
in t-tbar to be extended into the all-hadronic channel. In addition,
top-tagging can be used in t-tbar events when one of the tops decays
semi-leptonically, in events with missing energy, and in studies of b-tagging
efficiency at high pT.


title:
Vortices, zero modes and fractionalization in bilayer-graphene exciton
  condensate

abstract:
  A real-space formulation is given for the recently discussed exciton
condensate in a symmetrically biased graphene bilayer. We show that in the
continuum limit an oddly-quantized vortex in this condensate binds exactly one
zero mode per valley index of the bilayer. In the full lattice model the zero
modes are split slightly due to intervalley mixing. We support these results by
an exact numerical diagonalization of the lattice Hamiltonian. We also discuss
the effect of the zero modes on the charge content of these vortices and deduce
some of their interesting properties.


title:
Substructure and Scatter in the Mass-Temperature Relations of Simulated
  Clusters

abstract:
  Galaxy clusters exhibit regular scaling relations among their bulk
properties. These relations establish vital links between halo mass and cluster
observables. Precision cosmology studies that depend on these links benefit
from a better understanding of scatter in the mass-observable scaling
relations. Here we study the role of merger processes in introducing scatter
into the $M$-$T_{\rm X}$ relation, using a sample of 121 galaxy clusters
simulated with radiative cooling and supernova feedback, along with three
statistics previously proposed to measure X-ray surface brightness
substructure. These are the centroid variation ($w$), the axial ratio ($\eta$),
and the power ratios ($P_{20}$ and $P_{30}$). We find that in this set of
simulated clusters, each substructure measure is correlated with a cluster's
departures $\delta \ln T_{\rm X}$ and $\delta \ln M$ from the mean $M$-$T_{\rm
X}$ relation, both for emission-weighted temperatures $T_{\rm EW}$ and for
spectroscopic-like temperatures $T_{\rm SL}$, in the sense that clusters with
more substructure tend to be cooler at a given halo mass. In all cases, a
three-parameter fit to the $M$-$T_{\rm X}$ relation that includes substructure
information has less scatter than a two-parameter fit to the basic $M$-$T_{\rm
X}$ relation.


title: A Hubble Space Telescope transit light curve for GJ436b

abstract:
  We present time series photometry for six partial transits of GJ436b obtained
with the Fine Guidance Sensor instrument on the Hubble Space Telescope (HST).
Our analysis of these data yields independent estimates of the host star's
radius R_star = 0.505 +0.029/-0.020 R_sun, and the planet's orbital period P =
2.643882 +0.000060/-0.000058 d, orbital inclination i = 85.80 +0.21/-0.25 deg,
mean central transit time T_c = 2454455.279241 +0.00026/-0.00025 HJD, and
radius R_p = 4.90 +0.45/-0.33 R_earth. The radius we determine for the planet
is larger than the previous findings from analyses of an infrared light curve
obtained with the Spitzer Space Telescope. Although this discrepancy has a 92%
formal significance (1.7 sigma), it might be indicative of systematic errors
that still influence the analyses of even the highest-precision transit light
curves. Comparisons of all the measured radii to theoretical models suggest
that GJ436b has a H/He envelope of ~10% by mass. We also find that the transit
times for GJ436b are constant to within 10 s over the 11 planetary orbits that
the HST data span. However, the ensemble of published values exhibits a
long-term drift and our mean transit time is 128 s later than that expected
from the Spitzer ephemeris. The sparseness of the currently available data
hinders distinguishing between an error in the orbital period or perturbations
arising from an additional object in the system as the cause of the apparent
trend. Assuming the drift is due to an error in the orbital period we obtain an
improved estimate for it of P = 2.643904 +/- 0.000005 d. This value and our
measured transit times will serve as important benchmarks in future studies of
the GJ436 system. (abridged)


title: Explaining the mass-to-light ratios of globular clusters

abstract:
  The majority of observed mass-to-light ratios of globular clusters are too
low to be explained by `canonical' cluster models, in which dynamical effects
are not accounted for. Moreover, these models do not reproduce a recently
reported trend of increasing M/L with cluster mass, but instead predict
mass-to-light ratios that are independent of cluster mass for a fixed age and
metallicity. This study aims to explain the M/L of globular clusters in four
galaxies by including stellar evolution, stellar remnants, and the preferential
loss of low-mass stars due to energy equipartition. Analytical cluster models
are applied that account for stellar evolution and dynamical cluster
dissolution to samples of globular clusters in Cen A, the Milky Way, M31 and
the LMC. The models include stellar remnants and cover metallicities in the
range Z=0.0004-0.05. Both the low observed mass-to-light ratios and the trend
of increasing M/L with cluster mass can be reproduced by including the
preferential loss of low-mass stars, assuming reasonable values for the
dissolution timescale. This leads to a mass-dependent M/L evolution and
increases the explained percentage of the observations from 39% to 92%. This
study shows that the hitherto unexplained discrepancy between observations and
models of the mass-to-light ratios of globular clusters can be explained by
dynamical effects, provided that the globular clusters exhibiting low M/L have
dissolution timescales within the ranges assumed in this Letter. Furthermore,
it substantiates that M/L cannot be assumed to be constant with mass at fixed
age and metallicity.


title: Stability of Galactic Gas Disks and the Formation of Massive Clusters

abstract:
  We study gravitational instabilities in disks, with special attention to the
most massive clumps that form because they are expected to be the progenitors
of globular-type clusters. The maximum unstable mass is set by rotation and
depends only on the surface density and orbital frequency of the disk. We
propose that the formation of massive clusters is related to this largest scale
in galaxies not stabilized by rotation. Using data from the literature, we
predict that globular-like clusters can form in nuclear starburst disks and
protogalactic disks but not in typical spiral galaxies, in agreement with
observations.


title: Comment on "Arbitrated quantum-signature scheme"

abstract:
  We investigate the quantum signature scheme proposed by Zeng and Keitel
[Phys. Rev. A 65, 042312 (2002)]. It uses Greenberger-Horne-Zeilinger (GHZ)
states and the availability of a trusted arbitrator. However, in our opinion
the protocol is not clearly operationally defined and several steps are
ambiguous. Moreover, we argue that the security statements claimed by the
authors are incorrect.


title: Iterations of nonlinear entanglement witnesses

abstract:
  We describe a generic way to improve a given linear entanglement witness by a
quadratic, nonlinear term. This method can be iterated, leading to a whole
sequence of nonlinear witnesses, which become stronger in each step of the
iteration. We show how to optimize this iteration with respect to a given
state, and prove that in the limit of the iteration the nonlinear witness
detects all states that can be detected by the positive map corresponding to
the original linear witness.


title: New Proposed Mechanism of Actin-Polymerization-Driven Motility

abstract:
  We present the first numerical simulation of actin-driven propulsion by
elastic filaments. Specifically, we use a Brownian dynamics formulation of the
dendritic nucleation model of actin-driven propulsion. We show that the model
leads to a self-assembled network that exerts forces on a disk and pushes it
with an average speed. This simulation approach is the first to observe a speed
that varies non-monotonically with the concentration of branching proteins
(Arp2/3), capping protein and depolymerization rate (ADF), in accord with
experimental observations. Our results suggest a new interpretation of the
origin of motility that can be tested readily by experiment.


title:
A new (?) continued fraction expansion for the reciprocal of a
  $q$-series

abstract:
  We prove a continued fraction expansion for the reciprocal of a certain
$q$-series. All the specialists in the world are asked whether it is new or
not.


title:
Upper bounds on the performance of differential-phase-shift quantum key
  distribution

abstract:
  In this paper, we investigate limitations imposed by sequential attacks on
the performance of a differential-phase-shift (DPS) quantum key distribution
(QKD) protocol with weak coherent pulses. Specifically, we analyze a sequential
attack based on optimal unambiguous discrimination of the relative phases
between consecutive signal states emitted by the source. We show that this
attack can provide tighter upper bounds for the security of a DPS QKD scheme
than those derived from sequential attacks where the eavesdropper aims to
identify the state of each signal emitted by the source unambiguously.


title:
Summation formula over the zeros of the associated Legendre function
  with a physical application

abstract:
  Associated Legendre functions arise in many problems of mathematical physics.
By using the generalized Abel-Plana formula, in this paper we derive a
summation formula for the series over the zeros of the associated Legendre
function of the first kind with respect to the degree. The summation formula
for the series over the zeros of the Bessel function, previously discussed in
the literature, is obtained as a limiting case. The Wightman function for a
scalar field with general curvature coupling parameter is considered inside a
spherical boundary on background of constant negative curvature space. The
corresponding mode sum contains series over the zeros of the associated
Legendre function. The application of the summation formula allows us to
present the Wightman function in the form of the sum of two integrals. The
first one corresponds to the Wightman function for the bulk geometry without
boundaries and the second one is induced by the presence of the spherical
shell. For points away from the boundary the latter is finite in the
coincidence limit. In this way the renormalization of the vacuum expectation
value of the field squared is reduced to that for the boundary-free part.


title: On the Security of Liaw et al.'s Scheme

abstract:
  Recently, Liaw et al. proposed a remote user authentication scheme using
smartcards. They claimed a number of features of their scheme, e.g. a
dictionary of verification tables is not required to authenticate users; users
can choose their password freely; mutual authentication is provided between the
user and the remote system; the communication cost and the computational cost
are very low; users can update their password after the registration phase; a
session key agreed by the user and the remote system is generated in every
session; and the nonce-based scheme which does not require a timestamp (to
solve the serious time synchronization problem) etc.
  In this paper We show that Liaw et al.'s scheme does not stand with various
security requirements and is completely insecure.
  Keywords: Authentication, Smartcards, Remote system, Attack.


title:
Studying Cosmic Evolution with the XMM-Newton Distant Cluster Project:
  X-ray Luminous Galaxy Clusters at z>~1 and their Galaxy Populations

abstract:
  Investigating X-ray luminous galaxy clusters at z>~1 provides a fundamental
constraint on evolutionary studies of the largest virialized structures in the
Universe, the baryonic matter in form of the hot ICM, their galaxy populations,
and the effects of Dark Energy. The main aim of this work is to establish the
observational foundation for the XMM-Newton Distant Cluster Project (XDCP).
This new serendipitous survey is focused on the most distant systems at z>1,
based on the selection of extended X-ray sources, their identification as
clusters via two-band imaging, and their final spectroscopic confirmation.
Almost 1000 extended sources were selected as cluster candidates from the
analysis of 80 deg^2 of deep XMM-Newton archival data, of which 75% could be
readily identified as systems at z<~0.6. For the remaining 250 distant cluster
candidates a new strategy for their confirmation and redshift estimates was
adopted, based on Z- and H-band photometry and the observed Z-H red-sequence
color of early-type cluster galaxies. From observations of 25% of the sample,
more than 20 X-ray clusters were discovered at a photometric redshift of
z>~0.9. The new Z-H method has allowed a cluster sample study over an
unprecedented redshift baseline of 0.2<~z<~1.5. From a comparison of the
observed color evolution of the red-sequence with model predictions, the
formation epoch of early-type galaxies could be constrained as z_f=4.2+-1.1,
confirming their well-established old age. The preliminary investigation of the
H-band luminosity evolution of 63 BCGs provides for the first time direct
observational indications that the most massive cluster galaxies have doubled
their stellar mass since z~1.5. The finding that BCGs were assembled in the
last 9Gyr is now in qualitative agreement with the latest simulations.


title:
Quasars Probing Quasars III: New Clues to Feedback, Quenching, and the
  Physics of Massive Galaxy Formation

abstract:
  Galaxies hosting z~2 quasars are the high-$z$ progenitors of today's massive
`red-and-dead' galaxies. With close pairs of quasars at different redshifts, a
background quasar can be used to study a foreground quasar's halo gas in
absorption, providing a wealth of information about feedback, quenching, and
the physics of massive galaxy formation. We present a Keck/HIRES spectrum of
the bright background quasar in a projected pair with angular separation 13.3"
corresponding to 108kpc at the redshift of the foreground quasar z_fg=2.4360
+/- 0.0005, precisely determined from Gemini/GNIRS near-IR spectroscopy. Our
echelle spectrum reveals optically thick gas (NHI~10^19.7), coincident with the
foreground quasar redshift. The ionic transitions of associated metal-lines
reveal the following properties of the foreground quasar's halo: (1) the
kinematics are extreme with absorption extending to +780km/s relative to z_fg;
(2) the metallicity is nearly solar; (3) the temperature of the predominantly
ionized gas is T<~20,000K; (4) the electron density is n_e~1 cm^-3 indicating a
characteristic size ~10 - 100pc for the absorbing `clouds'; (7) there is a
negligible amount of warm gas 10^5K < T < 10^6K; (8) the gas is unlikely
illuminated by the foreground quasar, implying anisotropic or intermittent
emission. The mass of cold T~10^4K gas implied by our observations is
significant, amounting to a few percent of the total expected baryonic mass
density of the foreground quasar's dark halo at r~100kpc. The origin of this
material is still unclear, and we discuss several possibilities in the context
of current models of feedback and massive galaxy formation.


title:
Evolution of stellar collision products in open clusters. I. Blue
  stragglers in N-body models of M67

abstract:
  Stellar collisions are an important formation channel for blue straggler
stars in globular and old open clusters. Hydrodynamical simulations have shown
that the remnants of such collisions are out of thermal equilibrium, are not
strongly mixed and can rotate very rapidly.
  Detailed evolution models of collision products are needed to interpret
observed blue straggler populations and to use them to probe the dynamical
history of a star cluster. We expand on previous studies by presenting an
efficient procedure to import the results of detailed collision simulations
into a fully implicit stellar evolution code. Our code is able to evolve
stellar collision products in a fairly robust manner and allows for a
systematic study of their evolution.
  Using our code we have constructed detailed models of the collisional blue
stragglers produced in the $N$-body simulation of M67 performed by Hurley
\emph{et al.} in 2005. We assume the collisions are head-on and thus ignore the
effects of rotation in this paper.
  Our detailed models are more luminous than normal stars of the same mass and
in the same stage of evolution, but cooler than homogeneously mixed versions of
the collision products. The increased luminosity and inefficient mixing
decrease the remaining main-sequence lifetimes of the collision products, which
are much shorter than predicted by the simple prescription commonly used in
$N$-body simulations.


title: Maple Symbolic Computation in the Calculus of Variations

abstract:
  It is the aim of this work to identify and illustrate the potential and
weaknesses of the computer algebra system Maple in the area of the Calculus of
Variations: a classical area of mathematics that studies the methods for
finding maximum and minimum values of functionals of integral type. Variational
problems are usually solved with the help of the necessary optimality
conditions of Euler-Lagrange, which are, in general, nonlinear and difficult
second order differential equations to be solved. We show how the computer
algebra system Maple can be useful in the determination and resolution of these
equations. We will also present the solution to the celebrated brachistochrone
problem from the point of view of the calculus of variations and the Maple
system, and a reformulation of the classical problem obtained by restricting
the class of admissible functions.


title:
Evolution of stellar collision products in open clusters. II. A grid of
  low-mass collisions

abstract:
  In a companion paper we studied the detailed evolution of stellar collision
products that occurred in an $N$-body simulation of the old open cluster M67
and compared our detailed models to simple prescriptions. In this paper we
extend this work by studying the evolution of the collision products in open
clusters as a function of mass and age of the progenitor stars.
  We calculated a grid of head-on collisions covering the section of parameter
space relevant for collisions in open clusters. We create detailed models of
the merger remnants using an entropy-sorting algorithm and follow their
subsequent evolution during the initial contraction phase, through the main
sequence and up to the giant branch with our detailed stellar evolution code.
  We compare the location of our models in a colour-magnitude diagram to the
observed blue straggler population of the old open clusters M67 and NGC 188 and
find that they cover the observed blue straggler region of both clusters. For
M67, collisions need to have taken place recently. Differences between the
evolution tracks of the collision products and normal main sequence stars can
be understood quantitatively using a simple analytic model. We present an
analytic recipe that can be used in an $N$-body code to transform a precomputed
evolution track for a normal star into an evolution track for a collision
product.


title: Chandra's View of the Ram Pressure Stripped Galaxy M86

abstract:
  We present results from a mosaic of nine Chandra observations of M86 and the
surrounding field. We detect three main diffuse components: the Virgo ICM at
~2.4 keV, the extended halo of M86 at ~1.2 keV, and the cooler central and
stripped gas of M86 at ~0.8 keV. The most striking feature is a long tail of
emission, which consists of a plume ~ 4' north of M86 and two main extensions
emanating from the plume. Based on the morphology and temperature structure of
the tail, we conclude that it is formed by ram pressure stripping of M86 as it
falls into the Virgo cluster and interacts with the Virgo ICM, in agreement
with earlier work. The tail is 150 kpc in projection, and a simple estimate
gives a lower limit on the true length of the tail of 380 kpc, making this the
longest ram pressure stripped tail presently known. The total gas mass in the
plume (7x10^8 M_sun) and tail (1x10^9 M_sun) is about three times that in the
core of M86, which supports the scenario where most of the gas was stripped
rapidly and recently. The projected position of the plume can be understood if
M86 has an aspherical potential, as suggested by optical isophotes. Ram
pressure stripping from an aspherical potential can also explain the split
"double tails" seen in M86 and in other Virgo cluster galaxies in the field.
The large line-of-sight velocity of M86 (1550 km/s with respect to M87), its
position relative to the Virgo cluster, and the orientation of the tail tightly
constrain its orbital parameters. The data are inconsistent with a radial
orbit, and imply inner and outer turning radii of r_i ~ 300 kpc and r_o > 8.8
Mpc, indicating that M86 is, at best, only weakly bound to the Virgo cluster.


title: Noncommutative Dunkl operators and braided Cherednik algebras

abstract:
  We introduce braided Dunkl operators that are acting on a q-polynomial
algebra and q-commute. Generalizing the approach of Etingof and Ginzburg, we
explain the q-commutation phenomenon by constructing braided Cherednik algebras
for which the above operators form a representation. We classify all braided
Cherednik algebras using the theory of braided doubles developed in our
previous paper. Besides ordinary rational Cherednik algebras, our
classification gives new algebras attached to an infinite family of subgroups
of even elements in complex reflection groups, so that the corresponding
braided Dunkl operators pairwise anti-commute. We explicitly compute these new
operators in terms of braided partial derivatives and divided differences.


title: On an integrable two-component Camassa-Holm shallow water system

abstract:
  The interest in the Camassa-Holm equation inspired the search for various
generalizations of this equation with interesting properties and applications.
In this letter we deal with such a two-component integrable system of coupled
equations. First we derive the system in the context of shallow water theory.
Then we show that while small initial data develop into global solutions, for
some initial data wave breaking occurs. We also discuss the solitary wave
solutions. Finally, we present an explicit construction for the peakon
solutions in the short wave limit of system.


title:
Signatures of neutral quantum Hall modes in transport through
  low-density constrictions

abstract:
  Constrictions in fractional quantum Hall (FQH) systems not only facilitate
backscattering between counter-propagating edge modes, but also may reduce the
constriction filling fraction $\nu_c$ with respect to the bulk filling fraction
$\nu_b$. If both $\nu_b$ and $\nu_c$ correspond to incompressible FQH states,
at least part of the constriction region is surrounded by composite edges,
whose low energy dynamics is characterized by a charge mode and one or several
neutral modes. In the incoherent regime, decay of neutral modes describes the
equilibration of composite FQH edges, while in the limit of coherent transport,
the presence of neutral modes gives rise to universal conductance fluctuations.
In addition, neutral modes renormalize the strength of scattering across the
constriction, and thus can determine the relative strength of forward and
backwards scattering.


title: The Euler-Poincare theory of Metamorphosis

abstract:
  In the pattern matching approach to imaging science, the process of
``metamorphosis'' is template matching with dynamical templates. Here, we
recast the metamorphosis equations of into the Euler-Poincare variational
framework of and show that the metamorphosis equations contain the equations
for a perfect complex fluid \cite{Ho2002}. This result connects the ideas
underlying the process of metamorphosis in image matching to the physical
concept of order parameter in the theory of complex fluids. After developing
the general theory, we reinterpret various examples, including point set, image
and density metamorphosis. We finally discuss the issue of matching measures
with metamorphosis, for which we provide existence theorems for the initial and
boundary value problems.


title: Elliptic Littlewood identities

abstract:
  We prove analogues for elliptic interpolation functions of Macdonald's
version of the Littlewood identity for (skew) Macdonald polynomials, in the
process developing an interpretation of general elliptic "hypergeometric" sums
as skew interpolation functions. One such analogue has an interpretation as a
"vanishing integral", generalizing a result of arXiv:math/0606204; the
structure of this analogue gives sufficient insight to enable us to conjecture
elliptic versions of most of the other vanishing integrals of
arXiv:math/0606204 as well. We are thus led to formulate ten conjectures, each
of which can be viewed as a multivariate quadratic transformation, and can be
proved in a number of special cases.


title: Blow-up of generalized complex 4-manifolds

abstract:
  We introduce blow-up and blow-down operations for generalized complex
4-manifolds. Combining these with a surgery analogous to the logarithmic
transform, we then construct generalized complex structures on nCP2 # m
\bar{CP2} for n odd, a family of 4-manifolds which admit neither complex nor
symplectic structures unless n=1. We also extend the notion of a symplectic
elliptic Lefschetz fibration, so that it expresses a generalized complex
4-manifold as a fibration over a two-dimensional manifold with boundary.


title:
Extracting (n,g) direct capture cross sections from Coulomb
  dissociation: application to $^{14}$C(n,$\gamma$)$^{15}$C

abstract:
  A methodology for extracting neutron direct capture rates from Coulomb
dissociation data is developed and applied to the Coulomb dissociation of 15C
on 208Pb at 68 MeV/nucleon. Full Continuum Discretized Coupled Channel
calculations are performed and an asymptotic normalization coefficient is
determined from a fit to the breakup data. Direct neutron capture calculations
using the extracted asymptotic normalization coefficient provide $(n,\gamma)$
cross sections consistent with direct measurements. Our results show that the
Coulomb Dissociation data can be reliably used for extracting the cross section
for 14C(n,g)15C if the appropriate reaction theory is used. The resulting error
bars are of comparable magnitude to those from the direct measurement. This
procedure can be used more generally to extract capture cross sections from
breakup reactions whenever the desired capture process is fully peripheral.


title:
Towards sustainable transport: wireless detection of passenger trips on
  public transport buses

abstract:
  An important problem in creating efficient public transport is obtaining data
about the set of trips that passengers make, usually referred to as an
Origin/Destination (OD) matrix. Obtaining this data is problematic and
expensive in general, especially in the case of buses because on-board
ticketing systems do not record where and when passengers get off a bus. In
this paper we describe a novel and inexpensive system that uses off-the-shelf
Bluetooth hardware to accurately record passenger journeys. Here we show how
our system can be used to derive passenger OD matrices, and additionally we
show how our data can be used to further improve public transport services.


title: Fault-tolerant holonomic quantum computation

abstract:
  We explain how to combine holonomic quantum computation (HQC) with fault
tolerant quantum error correction. This establishes the scalability of HQC,
putting it on equal footing with other models of computation, while retaining
the inherent robustness the method derives from its geometric nature.


title:
Heavy Majorana Neutrinos in the Effective Lagrangian Description:
  Application to Hadron Colliders

abstract:
  We consider the effects of heavy Majorana neutrinos N with sub-TeV masses. We
argue that the mere presence of these particles would be a signal of physics
beyond the minimal seesaw mechanism and their interactions are, therefore, best
described using an effective Lagrangian. We then consider the complete set of
leading effective operators (up to dimension 6) involving the N and Standard
Model fields and show that these interactions can be relatively easy to track
at high-energy colliders. For example, we find that an exchange of a TeV-scale
heavy vector field can yield thousands of characteristic same-sign lepton
number violating l^+ l^+ j j events (j=light jet) at the LHC if m_N < 600 GeV,
which can also have a distinctive forward-backward asymmetry signal; even the
Tevatron has good prospects for this signature if m_N < 300 GeV.


title: A note on Artin-Markov normal form theorem for braid groups

abstract:
  In a recent paper by L. A. Bokut, V. V. Chaynikov and K. P. Shum in 2007,
Braid group $B_n$ is represented by Artin-Burau's relations. For such a
representation, it is told that all other compositions can be checked in the
same way. In this note, we support this claim and check all compositions.


title:
The Gram matrix of a Temperley-Lieb algebra is similar to the matrix of
  chromatic joins

abstract:
  In this paper we show that the matrix of chromatic joins and the Gram matrix
of the Temperley-Lieb algebra are similar (after rescaling), with the change of
basis given by diagonal matrices.


title: Characterization of Vibrating Plates by Bi-Laplacian Eigenvalue Problems

abstract:
  In this paper we derive boundary integral identities for the bi-Laplacian
eigenvalue problems under Dirichlet, Navier and simply-supported boundary
conditions. By using these identities, we first obtain the uniqueness criteria
for the solutions of the bi-Laplacian eigenvalue problems, and then prove that
each eigenvalue of the problem with simply-supported boundary condition
increases strictly with Poisson's ratio, thereby showing that each natural
frequency of a simply-supported vibrating plate increases strictly with
Poisson's ratio. In addition, we obtain boundary integral representations for
the strain energies of the vibrating plates under the three boundary
conditions.


title: On randomly placed arcs on the circle

abstract:
  We completely describe in terms of Hausdorff measures the size of the set of
points of the circle that are covered infinitely often by a sequence of random
arcs with given lengths. We also show that this set is a set with large
intersection.


title: Weighted grassmannians and stable hyperplane arrangements

abstract:
  We give a common generalization of (1) Hassett's weighted stable curves, and
(2) Hacking-Keel-Tevelev's stable hyperplane arrangements.


title:
Phase transitions induced by complex nonlinear noise in a system of
  self-propelled agents

abstract:
  We propose a comprehensive dynamical model for cooperative motion of
self-propelled particles, e.g., flocking, by combining well-known elements such
as velocity-alignment interactions, spatial interactions, and angular noise
into a unified Lagrangian treatment. Noise enters into our model in an
especially realistic way: it incorporates correlations, is highly nonlinear,
and it leads to a unique collective behavior. Our results show distinct
stability regions and an apparent change in the nature of one class of
noise-induced phase transitions, with respect to the mean velocity of the
group, as the range of the velocity-alignment interaction increases. This
phase-transition change comes accompanied with drastic modifications of the
microscopic dynamics, from nonintermittent to intermittent. Our results
facilitate the understanding of the origin of the phase transitions present in
other treatments.


title: Forward Physics at the LHC: within and beyond the Standard Model

abstract:
  We review the detection capabilities in the forward direction of the various
LHC experiments together with the associated physics programme. A selection of
measurements accessible with near-beam instrumentation in various sectors (and
extensions) of the Standard Model (SM) is outlined, including QCD (diffractive
and elastic scattering, low-x parton dynamics, hadronic Monte Carlos for
cosmic-rays), electroweak processes in gamma-gamma interactions, and Higgs
physics (vector-boson-fusion and central exclusive production).


title:
Gauge Invariance of the Muonium-Antimuonium Oscillation Time Scale and
  Limits on Right-Handed Neutrino Masses

abstract:
  The gauge invariance of the muonium-antimuonium ($M\bar{M}$) oscillation time
scale is explicitly demonstrated in the Standard Model modified only by the
inclusion of singlet right-handed neutrinos and allowing for general
renormalizable interactions. The see-saw mechanism is exploited resulting in
three light Majorana neutrinos and three heavy Majorana neutrinos with mass
scale $M_R\gg M_W$. The leading order matrix element contribution to the
$M\bar{M}$ oscillation process is computed in $R_\xi$ gauge and shown to be
$\xi$ independent thereby establishing the gauge invariance to this order.
Present experimental limits resulting from the non-observation of the
oscillation process sets a lower limit on $M_R$ roughly of order 600 GeV.


title:
Raman spectra in iron-based quaternary CeO$_{1-x}$F$_x$FeAs and
  LaO$_{1-x}$F$_x$FeAs

abstract:
  Raman spectra have been measured on iron-based quaternary
CeO$_{1-x}$F$_x$FeAs and LaO$_{1-x}$F$_x$FeAs with varying fluorine doping at
room temperatures. A group analysis has been made to clarify the optical modes.
Based on the first principle calculations, the observed phonon modes can be
assigned accordingly. In LaO$_{1-x}$F$_x$FeAs, the E$_g$ and A$_{1g}$ modes
related to the vibrations of La, are suppressed with increasing F doping.
However F doping only has a small effect on the E$_g$ and A$_{1g}$ modes of Fe
and As. The Raman modes of La and As are absent in rare-earth substituted
CeO$_{1-x}$F$_x$FeAs, and the E$_g$ mode of oxygen, corresponding to the
in-plane vibration of oxygen, moves to around 450 cm$^{-1}$ and shows a very
sharp peak. Electronic scattering background is low and electron-phonon
coupling is not evident for the observed phonon modes. Three features are found
above 500 cm$^{-1}$, which may be associated with multi-phonon process.
Nevertheless it is also possible that they are related to magnetic fluctuations
or interband transitions of d orbitals considering their energies.


title:
The use of Geant4 for simulations of a plastic beta-detector and its
  application to efficiency calibration

abstract:
  Precise beta-branching-ratio measurements are required in order to determine
ft-values as a part of our program to test the Electroweak Standard Model via
unitarity of the Cabibbo-Kobayashi-Moskawa matrix. For the measurements to be
useful in this test, their precision must be close to 0.1 %. In a
branching-ratio measurement, we position the radioactive sample between a thin
plastic scintillator used to detect beta-particles, and a HPGe detector for
gamma-rays. Both beta singles and beta-gamma coincidences are recorded.
Although the branching ratio depends most strongly on the HPGe detector
efficiency, it has some sensitivity to the energy dependence of the
beta-detector efficiency. We report here on a study of our beta-detector
response function, which used Monte Carlo calculations performed by the Geant4
toolkit. Results of the simulations are compared to measured beta-spectra from
several standard beta-sources.


title: Partial K-way negativities and three tangle for three qubit states

abstract:
  We obtain, analytically, the global negativity, partial $K-$way negativities
(K=2, 3), Wooter's tangle and three tangle for the generic three qubit
canonical state. It is found that the product of global negativity and partial
three way negativity is equal to three tangle, while the partial two way
negativity is related to tangle of qubit pairs. We also calculate similar
quantities for the state canonical to a single parameter (0<q<1) pure state
which is a linear combination of a GHZ state and a W state. In this case for
q=0.62685, the state has zero three tangle and zero three-way negativity,
having only W-like entanglement. The difference between the product of global
and partial three way negativity and three tangle for a given state is a
quantitative measure of two qubit coherences transformed by unitary
transformations on canonical state into three qubit coherences. The global
negativity and partial K-way negativities, obtained by selective partial
transpositions on multi-qubit state operator, satisfy inequalities which for
three qubits are equivalent to CKW (Coffman-Kundu-Wootter) inequality.


title:
A close relationship at z~2: submillimetre galaxies and BzK-selected
  galaxies

abstract:
  We investigate the relationship between two massive star-forming galaxy
populations at redshift z~ 2; i.e. submillimetre galaxies (SMGs) and
BzK-selected galaxies (BzKs). Out of 60 SMGs found in the Subaru/XMM-Newton
deep field, we collect optical--NIR photometry of 28 radio counterparts for 24
SMGs, based on refined sky positions with a radio map for 35 SMGs (Ivison et
al. 2007). We find a correlation between their K-band magnitudes and BzK [=
(z-K)-(B-z)] colours: almost all of the K-faint (K_AB > 21.3) radio-detected
SMGs have BzK>-0.2, and therefore BzKs. This result gives strong support to
perform direct optical identification of SMGs by searching for BzKs around
SMGs. We calculate the formal significance (P' value) for each of the BzK
associations around radio-undetected SMGs, and find 6 new robust
identifications, including one double identification. From this analysis, we
obtain the current best estimate on the surface density of BzK-selected SMGs,
which indicates that only ~1 per cent of BzKs are SMGs. If BzKs are normal
disk-like galaxies at z~ 2 as indicated by the correlation between their star
formation rate (SFR) and stellar mass and also by dynamical properties, SMGs
are likely to be merging BzKs. In this case, a typical enhancement of SFR due
to merging is only a factor of ~ 3, which is an order of magnitude lower than
that of local ULIRGs. This may indicate that most of the merging BzKs could be
observed as SMGs. Considering a possible high fraction of mergers at z~ 2 (at
least it would be higher than the fraction at z> 1 of ~ 10 per cent), it is
rather puzzling to find such a low fraction of SMGs in the progenitor
population, i.e. BzKs.


title: The Muon Magnetic Moment in the TeV Scale Seesaw Models

abstract:
  The reported discrepancy of the muon abnormal magnetic moment $a_\mu^{}$ has
impacts on the low energy phenomenology. In this paper we calculate the
corrections to $a_\mu$ in the standard model extended by the TeV scale seesaw
models. We show that the correction induced by the type-I seesaw model is
negative and of the order ${\cal O} (10^{-11})$, which can be neglected
compared with $a_\mu^{\rm SM}$. The correction induced by the type-II seesaw
model, which depends on the mass of the Higgs triplet $m_\Delta$ and the Yukawa
coupling $Y_\Delta$, can be of the order ${\cal O}(10^{-10})$ and compensate
for the discrepancy between $a_\mu^{\rm SM}$ and $a_{\mu}^{\rm exp}$. The
correction induced by the type-III seesaw model is also negative and can be of
the order ${\cal O}(10^{-10})$.


title: A Z' Boson and the Higgs Boson Mass

abstract:
  The Standard Model fit prefers values of the Higgs boson mass that are below
the 114 GeV direct lower limit from LEP II. The discrepancy is acute if the 3.2
sigma disagreement for the effective weak interaction mixing angle from the two
most precise measurements is attributed to underestimated systematic error. In
that case the data suggests new physics to raise the predicted value of the
Higgs mass. One of the simplest possibilities is a Z' boson, which would
generically increase the prediction for the Higgs mass as a result of Z-Z'
mixing. We explore the effect of Z-Z' mixing on the Higgs mass prediction,
using both the full data set and the reduced data set that omits the hadronic
asymmetry measurements of the weak mixing angle, which are more likely than the
leptonic asymmetry measurements to have underestimated systematic uncertainty.


title: Quantum noise theory for quantum transport through nanostructures

abstract:
  We develop a quantum noise approach to study quantum transport through
nanostructures. The nanostructures, such as quantum dots, are regarded as
artificial atoms, subject to quasi-equilibrium fermionic reservoirs of
electrons in biased leads. Noise operators characterizing the quantum
fluctuation in the reservoirs are related to the damping and fluctuation of the
artificial atoms through the quantum Langevin equation. The average current and
current noise are derived in terms of the reservoir noise correlations. In the
white-noise limit, we show that the current and current noise can be exactly
calculated by the quantum noise approach, even in the presence of interaction
such as Coulomb blockade. As a typical application, the average current and
current noise through a single quantum dot are studied.


title: On Zeros of Fourier Transforms

abstract:
  In this work we verify the sufficiency of a Jensen's necessary and sufficient
condition for a class of genus 0 or 1 entire functions to have only real zeros.
They are Fourier transforms of even, positive, indefinitely differentiable, and
very fast decreasing functions. We also apply our result to several important
special functions in mathematics, such as modified Bessel function $K_{iz}(a),\
a>0$ as a function of variable $z$, Riemann Xi function $\Xi(z)$, and character
Xi function $\Xi(z;\chi)$ when $\chi$ is a real primitive non-principal
character satisfying $\varphi(u;\chi)\ge0$ on the real line, we prove these
entire functions have only real zeros.


title:
Electromagnetic beam modulating through transformation optical
  structures

abstract:
  The transformation media concept based on the form-invariant Maxwell's
equations under coordinate transformations has opened up new possibilities to
manipulate the electromagnetic fields. In this paper we report on applying the
finite-embedded coordinate transformation method to design electromagnetic beam
modulating devices both in the Cartesian coordinates and in the cylindrical
coordinates. By designing the material constitutive tensors of the
transformation optical structures through different kinds of coordinate
transformations, either the beam width of an incident Gaussian plane wave could
be modulated by a slab, or the wave propagating direction of an
omni-directional source could be modulated through a cylindrical shell. We
present the design procedures and the full wave electromagnetic simulations
that clearly confirm the performance of the proposed beam modulating devices.


title: Convergence of the chiral expansion in two-flavor lattice QCD

abstract:
  We test the convergence property of the chiral perturbation theory (ChPT)
using a lattice QCD calculation of pion mass and decay constant with two
dynamical quark flavors. The lattice calculation is performed using the overlap
fermion formulation, which realizes exact chiral symmetry at finite lattice
spacing. By comparing various expansion prescriptions, we find that the chiral
expansion is well saturated at the next-to-leading order (NLO) for pions
lighter than $\sim$450 MeV. Better convergence behavior is found in particular
for a resummed expansion parameter $\xi$, with which the lattice data in the
pion mass region 290$\sim$750 MeV can be fitted well with the
next-to-next-to-leading order (NNLO) formulae. We obtain the results in
two-flavor QCD for the low energy constants $\bar{l}_3$ and $\bar{l}_4$ as well
as the pion decay constant, the chiral condensate, and the average up and down
quark mass.


title:
New infrared emission of the NV centre in diamond: Zeeman and uniaxial
  stress studies

abstract:
  An emission band in the infrared is shown to be associated with a transition
within the negative nitrogen-vacancy center in diamond. The band has a
zero-phonon line at 1046 nm, and uniaxial stress and magnetic field
measurements indicate that the emission is associated with a transition between
1E and 1A1 singlet levels. Inter-system crossing to these singlets causes the
spin polarisation that makes the NV- centre attractive for quantum information
processing, and the infrared emission band provides a new avenue for using the
centre in such applications.


title: Calculations of the spectra of superheavy elements E119 and E120+

abstract:
  High-precision calculations of the energy levels of the superheavy elements
E119 and E120+ are presented. Dominating correlation corrections beyond
relativistic Hartree-Fock are included to all orders in the Coulomb interaction
using the Feynman diagram technique and the correlation potential method. The
Breit interaction and quantum electrodynamics radiative corrections are
considered. Also, the volume isotope shift is determined. A similar treatment
for Cs, Fr, Ba+ and Ra+ is used to gauge the accuracy of the calculations and
to refine the ab initio results.


title: Observation of multiple sausage oscillations in cool postflare loop

abstract:
  Using simultaneous high spatial (1.3 arc sec) and temporal (5 and 10 s)
resolution H-alpha observations from the 15 cm Solar Tower Telescope at ARIES,
we study the oscillations in the relative intensity to explore the possibility
of sausage oscillations in the chromospheric cool postflare loop. We use
standard wavelet tool, and find the oscillation period of ~ 587 s near the loop
apex, and ~ 349 s near the footpoint. We suggest that the oscillations
represent the fundamental and the first harmonics of fast sausage waves in the
cool postflare loop. Based on the period ratio P1/P2 ~ 1.68, we estimate the
density scale height in the loop as ~ 17 Mm. This value is much higher than the
equilibrium scale height corresponding to H-alpha temperature, which probably
indicates that the cool postflare loop is not in hydrostatic equilibrium.
Seismologically estimated Alfv\'en speed outside the loop is ~ 300-330 km/s.
The observation of multiple oscillations may play a crucial role in
understanding the dynamics of lower solar atmosphere, complementing such
oscillations already reported in the upper solar atmosphere (e.g., hot flaring
loops).


title:
A novel method to construct stationary solutions of the Vlasov-Maxwell
  system : the relativistic case

abstract:
  A method to derive stationary solutions of the relativistic Vlasov-Maxwell
system is explored. In the non-relativistic case, a method using the Hermite
polynomial series to describe the deviation from the Maxwell-Boltzmann
distribution is found to be successful in deriving a few stationary solutions
including two dimensional one. Instead of the Hermite polynomial series, two
special orthogonal polynomial series, which are appropriate to expand the
deviation from the Maxwell-J\"uttner distribution, are introduced in this
paper. By applying this method, a new two-dimensional equilibrium is derived,
which may provide an initial setup for investigations of three-dimensional
relativistic collisionless reconnection of magnetic fields.


title:
A Nonparametric Approach to 3D Shape Analysis from Digital Camera Images
  - I. in Memory of W.P. Dayawansa

abstract:
  In this article, for the first time, one develops a nonparametric methodology
for an analysis of shapes of configurations of landmarks on real 3D objects
from regular camera photographs, thus making 3D shape analysis very accessible.
A fundamental result in computer vision by Faugeras (1992), Hartley, Gupta and
Chang (1992) is that generically, a finite 3D configuration of points can be
retrieved up to a projective transformation, from corresponding configurations
in a pair of camera images. Consequently, the projective shape of a 3D
configuration can be retrieved from two of its planar views. Given the inherent
registration errors, the 3D projective shape can be estimated from a sample of
photos of the scene containing that configuration. Projective shapes are here
regarded as points on projective shape manifolds. Using large sample and
nonparametric bootstrap methodology for extrinsic means on manifolds, one gives
confidence regions and tests for the mean projective shape of a 3D
configuration from its 2D camera images.


title: Cu, Pu and Fe high Tc superconductors: all the same mechanism!

abstract:
  The new iron based high Tc superconductors with Tc up to 55 K have stirred
new interest in this field. It is consensus that the BCS mechanism is not able
to explain the high Tc's. In the following we propose that spin holes in
antiferromagnetic clusters combine to make nonmagnetic bipolarons, which can
condense and lead to superconductivity.


title: Tridiagonal pairs and the q-tetrahedron algebra

abstract:
  In this paper we further develop the connection between tridiagonal pairs and
the q-tetrahedron algebra $\boxtimes_q$. Let V denote a finite dimensional
vector space over an algebraically closed field and let A, A^* denote a
tridiagonal pair on V. For $0 \leq i \leq d$ let $\theta_i$ (resp.
$\theta^*_i$) denote a standard ordering of the eigenvalues of A (resp. A^*).
Fix a nonzero scalar q which is not a root of unity. T. Ito and P. Terwilliger
have shown that when $\theta_i = q^{2i-d}$ and $\theta^*_i = q^{d-2i}$ there
exists an irreducible $\boxtimes_q$-module structure on V such that the
$\boxtimes_q$ generators x_{01}, x_{23} act as A, A^* respectively. In this
paper we examine the case in which there exists a nonzero scalar c in K such
that $\theta_i = q^{2i-d}$ and $\theta^*_i = q^{2i-d} + c q^{d-2i}$. In this
case we associate to A,A^* a polynomial P and prove the following equivalence.
The following are equivalent: (i) There exists a $\boxtimes_q$-module structure
on V such that x_{01} acts as A and x_{30} + cx_{23} acts as A^*, where x_{01},
x_{30}, x_{23} are standard generators for $\boxtimes_q$. (ii) P(q^{2d-2}
(q-q^{-1})^{-2}) \neq 0. Suppose (i),(ii) hold. Then the $\boxtimes_q$-module
structure on V is unique and irreducible.


title:
Fluctuations of energy flux in a simple dissipative out-of-equilibrium
  system

abstract:
  We report the statistical properties of the fluctuations of the energy flux
in an electronic RC circuit driven with a stochastic voltage. The fluctuations
of the power injected in the circuit are measured as a function of the damping
rate and the forcing parameters. We show that its distribution exhibits a cusp
close to zero and two asymmetric exponential tails, the asymmetry being driven
by the mean dissipation. This simple experiment allows to capture the
qualitative features of the energy flux distribution observed in more complex
dissipative systems. We also show that the large fluctuations of injected power
averaged on a time lag do not verify the Fluctuation Theorem even for long
averaging time. This is in contrast with the findings of previous experiments
due to their small range of explored fluctuation amplitude. The injected power
in a system of N components either correlated or not is also studied to mimic
systems with large number of particles, such as in a dilute granular gas.

categories: cond-mat.stat-mech cond-mat.other math.ST stat.TH


title: On the Capacity of Gaussian Relay Channels

abstract:
  This paper has been withdrawn due to that the same conclusion has been
proposed before.


title: Involutions of 3-dimensional handlebodies

abstract:
  We study the orientation preserving involutions of the orientable
3-dimensional handlebody $H_g$, for any genus $g$. A complete classification of
such involutions is given in terms of their fixed points.


title:
Channel Capacity Limits of Cognitive Radio in Asymmetric Fading
  Environments

abstract:
  Cognitive radio technology is an innovative radio design concept which aims
to increase spectrum utilization by exploiting unused spectrum in dynamically
changing environments. By extending previous results, we investigate the
capacity gains achievable with this dynamic spectrum approach in asymmetric
fading channels. More specifically, we allow the secondary-to-primary and
secondary-to-secondary user channels to undergo Rayleigh or Rician fading, with
arbitrary link power. In order to compute the capacity, we derive the
distributions of ratios of Rayleigh and Rician variables. Compared to the
symmetric fading scenario, our results indicate several interesting features of
the capacity behaviour under both average and peak received power constraints.
Finally, the impact of multiple primary users on the capacity under asymmetric
fading has also been studied.


title: Homotopy Type of the Boolean Complex of a Coxeter System

abstract:
  In any Coxeter group, the set of elements whose principal order ideals are
boolean forms a simplicial poset under the Bruhat order. This simplicial poset
defines a cell complex, called the boolean complex. In this paper it is shown
that, for any Coxeter system of rank n, the boolean complex is homotopy
equivalent to a wedge of (n-1)-dimensional spheres. The number of such spheres
can be computed recursively from the unlabeled Coxeter graph, and defines a new
graph invariant called the boolean number. Specific calculations of the boolean
number are given for all finite and affine irreducible Coxeter systems, as well
as for systems with graphs that are disconnected, complete, or stars. One
implication of these results is that the boolean complex is contractible if and
only if a generator of the Coxeter system is in the center of the group. of
these results is that the boolean complex is contractible if and only if a
generator of the Coxeter system is in the center of the group.


title:
Experimental demonstration of deterministic one-way quantum computing on
  a NMR quantum computer

abstract:
  One-way quantum computing is an important and novel approach to quantum
computation. By exploiting the existing particle-particle interactions, we
report the first experimental realization of the complete process of
deterministic one-way quantum Deutsch-Josza algorithm in NMR, including graph
state preparation, single-qubit measurements and feed-forward corrections. The
findings in our experiment may shed light on the future scalable one-way
quantum computation.


title: High frequency sound in superfluid 3He-B

abstract:
  We present measurements of the absolute phase velocity of transverse and
longitudinal sound in superfluid 3He-B at low temperature, extending from the
imaginary squashing mode to near pair-breaking. Changes in the transverse phase
velocity near pair-breaking have been explained in terms of an order parameter
collective mode that arises from f-wave pairing interactions, the so-called
J=4- mode. Using these measurements, we establish lower bounds on the energy
gap in the B-phase. Measurement of attenuation of longitudinal sound at low
temperature and energies far above the pair-breaking threshold, are in
agreement with the lower bounds set on pair-breaking. Finally, we discuss our
estimations for the strength of the f-wave pairing interactions and the Fermi
liquid parameter, F4s.


title: Outage and Local Throughput and Capacity of Random Wireless Networks

abstract:
  Outage probabilities and single-hop throughput are two important performance
metrics that have been evaluated for certain specific types of wireless
networks. However, there is a lack of comprehensive results for larger classes
of networks, and there is no systematic approach that permits the convenient
comparison of the performance of networks with different geometries and levels
of randomness.
  The uncertainty cube is introduced to categorize the uncertainty present in a
network. The three axes of the cube represent the three main potential sources
of uncertainty in interference-limited networks: the node distribution, the
channel gains (fading), and the channel access (set of transmitting nodes). For
the performance analysis, a new parameter, the so-called {\em spatial
contention}, is defined. It measures the slope of the outage probability in an
ALOHA network as a function of the transmit probability $p$ at $p=0$. Outage is
defined as the event that the signal-to-interference ratio (SIR) is below a
certain threshold in a given time slot. It is shown that the spatial contention
is sufficient to characterize outage and throughput in large classes of
wireless networks, corresponding to different positions on the uncertainty
cube. Existing results are placed in this framework, and new ones are derived.
  Further, interpreting the outage probability as the SIR distribution, the
ergodic capacity of unit-distance links is determined and compared to the
throughput achievable for fixed (yet optimized) transmission rates.


title:
Electronic State of Na_xCoO_2 Based on the Two Dimensional Triangular
  Lattice d-p Model

abstract:
  The electronic state in a CoO_2 plane of the layered cobalt oxides
Na_{x}CoO_2 is investigated by using the 11 band d-p model on a two-dimensional
triangular lattice, where the tight-binding parameters are determined so as to
fit the LDA band structure. Effects of the Coulomb interaction at a Co site:
the intra- and inter-orbital direct terms U and U', the exchange coupling J and
the pair-transfer J', are treated within the Hartree-Fock approximation. We
also consider the effect of the Na order at x=0.5, where Na ions form one
dimensional chains, by taking into account of an effective one-dimensional
potential Delta epsilon_{d} on the CoO_2 plane. It is found that the Na order
enhances the Fermi surface nesting resulting in the antiferromagnetism (AFM)
which is suppressed due to the frustration effect in the case without the Na
order. When U and Delta epsilon_{d} are varied, we observe three types of the
AFM: (1) the metallic AFM with large density of states N_F at the Fermi level
for small values of U and Delta epsilon_{d}, (2) the semimetallic AFM with tiny
N_F for large U with small Delta epsilon_{d} and (3) the insulating AFM with a
finite energy gap for large values of U and Delta epsilon_{d}.


title:
Antiferromagnetic, Charge and Orbital Ordered States of Na0.5CoO2 Based
  on the Two-Dimensional Triangular Lattice d-p Model

abstract:
  We investigate the electronic state of a CoO_2 plane in the layered cobalt
oxides Na_xCoO_2 using the 11 band d-p model on a two-dimensional triangular
lattice, where the tight-binding parameters are determined so as to fit the LDA
band structure. Effects of the Coulomb interaction at a Co site: the intra- and
inter-orbital direct terms U and U', the exchange coupling J and the
pair-transfer J', are treated within the Hartree-Fock approximation. We also
consider the effect of the Na order at x=0.5, where Na ions form
one-dimensional chains, by taking into account of an effective one-dimensional
potential Delta epsilon_{d}. It is found that the one-dimensional Na order
enhances the Fermi surface nesting and antiferromagnetism is caused which is
suppressed due to the frustration effect in the case without the Na order. %It
is found that the Na order enhances the Fermi surface nesting resulting in a
metallic antiferromagnetism which is suppressed due to the frustration effect
in the case without the Na order. Furthermore, we consider the effect of the
Coulomb interaction between the nearest-neighbor Co sites V and find that a
coexistence of the magnetic, charge and orbital ordered state takes place for
V>V_c where the system becomes insulator.


title: On the possibility of metamaterial properties in spin plasmas

abstract:
  The fluid theory of plasmas is extended to include the properties of electron
spin. The linear theory of waves in a magnetized plasma is presented, and it is
shown that the spin effects causes a change of the magnetic permeability.
Furthemore, by changing the direction of the external magnetic field, the
magnetic permability may become negative. This leads to instabilities in the
long wavelength regimes. If these can be controlled, however, the spin plasma
becomes a metamaterial for a broad range of frequencies, i.e. above the ion
cyclotron frequency but below the electron cyclotron frequency. The
consequences of our results are discussed.


title:
Edge-state Fabry-Perot interferometer as a high sensitivity charge
  detector

abstract:
  We present a scheme for high sensitivity charge detection in the integer
quantum Hall regime using two point contacts in a series. The setup is an
electronic analog of an optical Fabry-Perot interferometer. We show that for
small transmission through the point contacts the sensitivity of the
interferometer is very high due to multiple reflections at the point contacts.
The sensitivity can be further enhanced twice by using electrons in spin
entangled state. We show that for point contacts having different reflection
probabilities, the interferometer can be tuned for the quantum limited
measurement.


title:
Computation of Topological Entropy via $\phi$-expansion, an Inverse
  Problem for the Dynamical Systems $\beta x+\alpha \mod 1$

abstract:
  We give an algorithm, based on the $\phi$-expansion of Parry, in order to
compute the topological entropy of a class of shift spaces. The idea is the
solve an inverse problem for the dynamical systems $\beta x+\alpha \mod1$.The
first part is an exposition of the $\phi$-expansion applied to piecewise
monotone dynamical systems. We formulate for the validity of the
$\phi$-expansion, necessary and sufficient conditions, which are different from
those in Parry's paper.


title: High-energy photon collisions at the LHC - dream or reality?

abstract:
  We discuss the potential of high-energy photon collisions at the LHC for
improving our understanding of QCD and studying the physics beyond the Standard
Model. After reviewing briefly the legacy of past photoproduction experiments
at LEP and HERA, we examine the gold-plated channels proposed for a photon
collider at the ILC for their potential in a hadron collider environment. We
stress that initial-state photon interactions have indeed been observed at RHIC
and at the Tevatron. Three promising channels at the LHC are then presented in
some detail: exclusive vector-meson production, measurements of possibly
anomalous electroweak gauge-boson or top-quark couplings, and slepton
production.


title: Perfect fluid and scalar field in the Reissner-Nordstrom metric

abstract:
  We describe spherically symmetric steady-state accretion of perfect fluid in
the Reissner-Nordstrom metric. We present analytic solutions for accretion of a
fluid with the linear equations of state and of the Chaplygin gas. It is also
shown that, under reasonable physical conditions, there is no steady-state
accretion of a perfect fluid onto a Reissner-Nordstrom naked singularity.
Instead, a static atmosphere of fluid is formed. We discuss a possibility of
violation of the third law of black hole thermodynamics for a phantom fluid
accretion.


title: Reflected Solutions of Backward Doubly Stochastic Differential Equations

abstract:
  We study reflected solutions of one-dimensional backward doubly stochastic
differential equations (BDSDEs in short). The "reflected" keeps the solution
above a given stochastic process. We get the uniqueness and existence by
penalization. For the existence of backward stochastic integral, our proof is
different from [KKPPQ] slightly. We also obtain a comparison theorem for
reflected BDSDEs.


title:
Asymptotics of the maximal radius of an $L^r$-optimal sequence of
  quantizers

abstract:
  Let $P$ be a probability distribution on $\mathbb{R}^d$ (equipped with an
Euclidean norm $|\cdot|$). Let $ r> 0 $ and let $(\alpha_n)_{n \geq1}$ be an
(asymptotically) $L^r(P)$-optimal sequence of $n$-quantizers. We investigate
the asymptotic behavior of the maximal radius sequence induced by the sequence
$(\alpha_n)_{n \geq1}$ defined for every $n \geq1$ by $\rho(\alpha_n) =
\max{|a|, a \in\alpha_n}$. When $\card(\supp(P))$ is infinite, the maximal
radius sequence goes to $\sup{|x|, x \in\operatorname{supp}(P)}$ as $n$ goes to
infinity. We then give the exact rate of convergence for two classes of
distributions with unbounded support: distributions with hyper-exponential
tails and distributions with polynomial tails. In the one-dimensional setting,
a sharp rate and constant are provided for distributions with hyper-exponential
tails.


title: Calculus on Lie algebroids, Lie groupoids and Poisson manifolds

abstract:
  We begin with a short presentation of the basic concepts related to Lie
groupoids and Lie algebroids, but the main part of this paper deals with Lie
algebroids. A Lie algebroid over a manifold is a vector bundle over that
manifold whose properties are very similar to those of a tangent bundle. Its
dual bundle has properties very similar to those of a cotangent bundle: in the
graded algebra of sections of its external powers, one can define an operator
similar to the exterior derivative. We present the theory of Lie derivatives,
Schouten-Nijenhuis brackets and exterior derivatives in the general setting of
a Lie algebroid, its dual bundle and their exterior powers. All the results
(which, for their most part, are already known) are given with detailed proofs.
In the final sections, the results are applied to Poisson manifolds, whose
links with Lie algebroids are very close.


title:
Drawing (Complete) Binary Tanglegrams: Hardness, Approximation,
  Fixed-Parameter Tractability

abstract:
  A \emph{binary tanglegram} is a drawing of a pair of rooted binary trees
whose leaf sets are in one-to-one correspondence; matching leaves are connected
by inter-tree edges. For applications, for example, in phylogenetics, it is
essential that both trees are drawn without edge crossings and that the
inter-tree edges have as few crossings as possible. It is known that finding a
tanglegram with the minimum number of crossings is NP-hard and that the problem
is fixed-parameter tractable with respect to that number.
  We prove that under the Unique Games Conjecture there is no constant-factor
approximation for binary trees. We show that the problem is NP-hard even if
both trees are complete binary trees. For this case we give an $O(n^3)$-time
2-approximation and a new, simple fixed-parameter algorithm. We show that the
maximization version of the dual problem for binary trees can be reduced to a
version of MaxCut for which the algorithm of Goemans and Williamson yields a
0.878-approximation.


title: The Mixing Time of Glauber Dynamics for Colouring Regular Trees

abstract:
  We consider Metropolis Glauber dynamics for sampling proper $q$-colourings of
the $n$-vertex complete $b$-ary tree when $3\leq q\leq b/2\ln(b)$. We give both
upper and lower bounds on the mixing time. For fixed $q$ and $b$, our upper
bound is $n^{O(b/\log b)}$ and our lower bound is $n^{\Omega(b/q \log(b))}$,
where the constants implicit in the $O()$ and $\Omega()$ notation do not depend
upon $n$, $q$ or $b$.


title: The sawtooth chain: From Heisenberg spins to Hubbard electrons

abstract:
  We report on recent studies of the spin-half Heisenberg and the Hubbard model
on the sawtooth chain. For both models we construct a class of exact
eigenstates which are localized due to the frustrating geometry of the lattice
for a certain relation of the exchange (hopping) integrals. Although these
eigenstates differ in details for the two models because of the different
statistics, they share some characteristic features. The localized eigenstates
are highly degenerate and become ground states in high magnetic fields
(Heisenberg model) or at certain electron fillings (Hubbard model),
respectively. They may dominate the low-temperature thermodynamics and lead to
an extra low-temperature maximum in the specific heat. The ground-state
degeneracy can be calculated exactly by a mapping of the manifold of localized
ground states onto a classical hard-dimer problem, and explicit expressions for
thermodynamic quantities can be derived which are valid at low temperatures
near the saturation field for the Heisenberg model or around a certain value of
the chemical potential for the Hubbard model, respectively.


title:
Modeling the Structure and Dynamics of the Consonant Inventories: A
  Complex Network Approach

abstract:
  We study the self-organization of the consonant inventories through a complex
network approach. We observe that the distribution of occurrence as well as
cooccurrence of the consonants across languages follow a power-law behavior.
The co-occurrence network of consonants exhibits a high clustering coefficient.
We propose four novel synthesis models for these networks (each of which is a
refinement of the earlier) so as to successively match with higher accuracy (a)
the above mentioned topological properties as well as (b) the linguistic
property of feature economy exhibited by the consonant inventories. We conclude
by arguing that a possible interpretation of this mechanism of network growth
is the process of child language acquisition. Such models essentially increase
our understanding of the structure of languages that is influenced by their
evolutionary dynamics and this, in turn, can be extremely useful for building
future NLP applications.


title:
UV caps, IR modification of gravity, and recovery of 4D gravity in
  regularized braneworlds

abstract:
  In the context of six-dimensional conical braneworlds we consider a simple
and explicit model that incorporates long distance modification of gravity and
regularization of codimension-2 singularities. To resolve the conical
singularities we replace the codimension-2 branes with ring-like codimension-1
branes, filling in the interiors with regular caps. The six-dimensional Planck
scale in the cap is assumed to be much greater than the bulk Planck scale,
which gives rise to the effect analogous to brane-induced gravity. Weak gravity
on the regularized brane is studied in the case of a sharp conical bulk. We
show by a linear analysis that gravity at short distances is effectively
described by the four-dimensional Brans-Dicke theory, while the higher
dimensional nature of gravity emerges at long distances. The linear analysis
breaks down at some intermediate scale, below which four-dimensional Einstein
gravity is shown to be recovered thanks to the second-order effects of the
brane bending.


title:
Swift uncovers that SAX J0840.7+2248 is not an X-ray Binary, but
  BeppoSAX X-ray Rich GRB 980429

abstract:
  During our Swift/XRT program to obtain X-ray positions at arcsecond level for
a sample of Galactic X-ray binaries, we discovered that SAX J0840.7+2248 is not
a binary, but rather BeppoSAX/WFC+GRBM X-ray Rich GRB 980429. Here we report on
this discovery and on the properties of this long, X-ray rich gamma-ray burst,
from prompt to (very) late followup.


title:
High pressure synthesis of late rare earth RFeAs(O,F) superconductors; R
  = Tb and Dy

abstract:
  New TbFeAs(O,F) and DyFeAs(O,F) superconductors with critical temperatures
Tc= 46 and 45 K and very high critical fields over 100 T have been prepared at
1100- 1150C and 10-12 GPa, demonstrating that high pressure may be used to
synthesise late rare earth derivatives of the recently reported RFeAs(O,F) (R =
La - Nd, Sm, Gd) high temperature superconductors.


title: Asteroseismic constraints on the OPAL opacity interpolation

abstract:
  The frequency difference between a model used only two-point interpolation of
opacity and a model used piecewise linear interpolation of opacity is of the
order of several microHertz at a certain stage, which is almost 10 times worse
than the observational precision of p-modes of solar-like stars. Therefore, the
two-point interpolation of opacity is unsuitable in modelling of solar-like
stars with element diffusion.


title: Drawing Binary Tanglegrams: An Experimental Evaluation

abstract:
  A binary tanglegram is a pair <S,T> of binary trees whose leaf sets are in
one-to-one correspondence; matching leaves are connected by inter-tree edges.
For applications, for example in phylogenetics or software engineering, it is
required that the individual trees are drawn crossing-free. A natural
optimization problem, denoted tanglegram layout problem, is thus to minimize
the number of crossings between inter-tree edges.
  The tanglegram layout problem is NP-hard and is currently considered both in
application domains and theory. In this paper we present an experimental
comparison of a recursive algorithm of Buchin et al., our variant of their
algorithm, the algorithm hierarchy sort of Holten and van Wijk, and an integer
quadratic program that yields optimal solutions.


title:
Wind structure of late B supergiants I. Multi-line analyses of
  near-surface and wind structure in HD 199 478 (B8 Iae)

abstract:
  We provide a quantitative analysis of time-variable phenomena in the
photospheric, near-star, and outflow regions of the late-B supergiant (SG) HD
199478. The analysis is based primarily on optical spectroscopic datasets
secured between 1999 and 2000 from the Bulgarian NAO, Tartu, and Ritter
Observatories. The temporal behaviour of HD 199478 is characterised by three
key empirical properties: (i) systematic central velocity shifts in the
photospheric absorption lines, including C II and He I, over a characteristic
time-scale of abou 20 days; (ii) extremely strong, variable H alpha emission
with no clear modulation signal, and (iii) the occurrence in 2000 of a (rare)
high-velocity absorption (HVA) event in H alpha, which evolved over about 60
days, showing the clear signature of mass infall and outflows. In these
properties HD 199478 resembles few other late-B SGs with peculiar emission and
HVAs in H alpha (HD 91619, HD 34085, HD 96919). Non-LTE line synthesis
modelling is conducted using FASTWIND for these late-B SGs to constrain and
compare their fundamental parameters within the context of extreme behaviour in
the H alpha lines. Our analysis indicate that at the cooler temperature edge of
B SGs, there are objects whose wind properties, as traced by H alpha, are
inconsistent with the predictions of the smooth, spherically symmetric wind
approximation. This discordance is still not fully understood and may highlight
the role of a non-spherical, disk-like, geometry, which may result from
magnetically-driven equatorial compression of the gas. Ordered dipole magnetic
fields may also lead to confined plasma held above the stellar surface, which
ultimately gives rise to transient HVA events.


title: Matching univalent functions and conformal welding

abstract:
  Given a conformal mapping $f$ of the unit disk $\mathbb D$ onto a simply
connected domain $D$ in the complex plane bounded by a closed Jordan curve, we
consider the problem of constructing a matching conformal mapping, i.e., the
mapping of the exterior of the unit disk $\mathbb D^*$ onto the exterior domain
$D^*$ regarding to $D$. The answer is expressed in terms of a linear
differential equation with a driving term given as the kernel of an operator
dependent on the original mapping $f$. Examples are provided. This study is
related to the problem of conformal welding and to representation of the
Virasoro algebra in the space of univalent functions.


title:
Public Channel Cryptography: Chaos Synchronization and Hilbert's Tenth
  Problem

abstract:
  The synchronization process of two mutually delayed coupled deterministic
chaotic maps is demonstrated both analytically and numerically. The
synchronization is preserved when the mutually transmitted signal is concealed
by two commutative private filters that are placed on each end of the
communication channel. We demonstrate that when the transmitted signal is a
convolution of the truncated time delayed output signals or some powers of the
delayed output signals synchronization is still maintained. The task of a
passive attacker is mapped onto Hilbert's tenth problem, solving a set of
nonlinear Diophantine equations, which was proven to be in the class of
NP-Complete problems. This bridge between two different disciplines,
synchronization in nonlinear dynamical processes and the realm of the NPC
problems, opens a horizon for a new type of secure public-channel protocols.


title:
A path integral approach to closed-form option pricing formulas with
  applications to stochastic volatility and interest rate models

abstract:
  We present a path integral method to derive closed-form solutions for option
prices in a stochastic volatility model. The method is explained in detail for
the pricing of a plain vanilla option. The flexibility of our approach is
demonstrated by extending the realm of closed-form option price formulas to the
case where both the volatility and interest rates are stochastic. This
flexibility is promising for the treatment of exotic options. Our new
analytical formulas are tested with numerical Monte Carlo simulations.


title: Cycles Of Given Length In Oriented Graphs

abstract:
  We show that for each \ell\geq 4 every sufficiently large oriented graph G
with \delta^+(G), \delta^-(G) \geq \lfloor |G|/3 \rfloor +1 contains an
\ell-cycle. This is best possible for all those \ell\geq 4 which are not
divisible by 3. Surprisingly, for some other values of \ell, an \ell-cycle is
forced by a much weaker minimum degree condition. We propose and discuss a
conjecture regarding the precise minimum degree which forces an \ell-cycle
(with \ell \geq 4 divisible by 3) in an oriented graph. We also give an
application of our results to pancyclicity and consider \ell-cycles in general
digraphs.


title: Prime pairs and Zeta's zeros

abstract:
  There is extensive numerical support for the prime-pair conjecture (PPC) of
Hardy and Littlewood (1923) on the asymptotic behavior of pi_{2r}(x), the
number of prime pairs (p,p+2r) with p not exceeding x. However, it is still not
known whether there are infinitely many prime pairs with given even difference!
Using a strong hypothesis on (weighted) equidistribution of primes in
arithmetic progressions, Goldston, Pintz and Yildirim have shown (2007) that
there are infinitely many pairs of primes differing by at most sixteen. The
present author uses a Tauberian approach to derive that the PPC is equivalent
to specific boundary behavior of certain functions involving zeta's complex
zeros. Under Riemann's Hypothesis and on the real axis, these functions
resemble pair-correlation expressions. A speculative extension of Montgomery's
classical work (1973) would imply that there must be an abundance of prime
pairs.


title:
Diagnostic of the temperature and differential emission measure (DEM)
  based on Hinode/XRT data

abstract:
  We discuss here various methodologies and an optimal strategy of the
temperature and emission measure diagnostics based on Hinode X-Ray Telescope
data. As an example of our results we present determination of the temperature
distribution of the X-rays emitting plasma using filters ratio method and three
various methods of the calculation of the differential emission measure (DEM).
We have found that all these methods give results similar to the two filters
ratio method. Additionally, all methods of the DEM calculation gave similar
solutions. We can state that the majority of the pairs of the Hinode filters
allows one to derive the temperature and emission measure in the isothermal
plasma approximation using standard diagnostic based on two filters ratio
method. In cases of strong flares one can also expect well conformity of the
results obtained using a Withbroe - Sylwester, genetic algorithm and
least-square methods of the DEM evaluation.


title:
On convergence-sensitive bisimulation and the embedding of CCS in timed
  CCS

abstract:
  We propose a notion of convergence-sensitive bisimulation that is built just
over the notions of (internal) reduction and of (static) context. In the
framework of timed CCS, we characterise this notion of `contextual'
bisimulation via the usual labelled transition system. We also remark that it
provides a suitable semantic framework for a fully abstract embedding of
untimed processes into timed ones. Finally, we show that the notion can be
refined to include sensitivity to divergence.