title:
Structure of bottle-brush polymers in solution: A Monte Carlo test of
  models for the scattering function

abstract:
  Extensive Monte Carlo results are presented for a lattice model of a
bottle-brush polymer under good solvent or Theta solvent conditions. Varying
the side chain length, backbone length, and the grafting density for a rigid
straight backbone, both radial density profiles of monomers and side chain ends
are obtained, as well as structure factors describing the scattering from a
single side chain and from the total bottle-brush polymer. To describe the
structure in the interior of a very long bottle-brush, a periodic boundary
condition in the direction along the backbone is used, and to describe effects
due to the finiteness of the backbone length, a second set of simulations with
free ends of the backbone is performed. In the latter case, the inhomogeneity
of the structure in the direction along the backbone is carefully investigated.
We use these results to test various phenomenological models that have been
proposed to interpret experimental scattering data for bottle-brush
macromolecules. These models aim to extract information on the radial density
profile of a bottle-brush from the total scattering via suitable convolution
approximations. Possibilities to improve such models, guided by our simulation
results, are discussed.


title:
Volume capture and volume reflection of ultrarelativistic particles in
  bent single crystals

abstract:
  Influence of volume capture on a process of volume reflection of
ultrarelativistic particles moving in bent single crystals was considered
analytically. Relations describing various distributions of particles involving
in the process, the probability of volume capture and behavior of channeling
and dechanneling fractions of a beam were obtained. Results of study will be
useful at creation of multicrystal devices for collimation and extraction of
beams on modern and future accelerators.


title: Observation of B0 -> chi_c0K*0 and evidence for B+ -> chi_c0K*+

abstract:
  We present the observation of the decay B0 -> chi_c0K*0 as well as evidence
of B+ -> chi_c0K*+, with an 8.9 and a 3.6 standard deviation significance,
respectively, using a data sample of 454 million Y(4S) -> BB decays collected
with the BaBar detector at the PEP-II B meson factory located at the Stanford
Linear Accelerator Center (SLAC). The measured branching fractions are: B(B0 ->
chi_c0K*0) = (1.7 +/- 0.3 +/- 0.2) * 10^{-4} and B(B+ -> chi_c0K^*+) = (1.4 +/-
0.5 +/- 0.2) * 10^{-4}, where the first quoted errors are statistical and the
second are systematic. We obtain a branching fraction upper limit of B(B+ ->
chi_c0K*+) < 2.1 * 10^{-4} at the 90% confidence level.


title:
Escape transition of a polymer chain from a nanotube: how to avoid
  spurious results by use of the force-biased pruned-enriched Rosenbluth
  algorithm

abstract:
  A polymer chain containing $N$ monomers confined in a finite cylindrical tube
of diameter $D$ grafted at a distance $L$ from the open end of the tube may
undergo a rather abrupt transition, where part of the chain escapes from the
tube to form a "crown-like" coil outside of the tube. When this problem is
studied by Monte Carlo simulation of self-avoiding walks on the simple cubic
lattice applying a cylindrical confinement and using the standard
pruned-enriched Rosenbluth method (PERM), one obtains spurious results,
however: with increasing chain length the transition gets weaker and weaker,
due to insufficient sampling of the "escaped" states, as a detailed analysis
shows. In order to solve this problem, a new variant of a biased sequential
sampling algorithm with re-sampling is proposed, force-biased PERM: the
difficulty of sampling both phases in the region of the first order transition
with the correct weights is treated by applying a force at the free end pulling
it out of the tube. Different strengths of this force need to be used and
reweighting techniques are applied. Using rather long chains (up to N=18000)
and wide tubes (up to D=29 lattice spacings), the free energy of the chain, its
end-to-end distance, the number of "imprisoned" monomers can be estimated, as
well as the order parameter and its distribution. It is suggested that this new
algorithm should be useful for other problems involving state changes of
polymers, where the different states belong to rather disjunct "valleys" in the
phase space of the system.


title:
Effect of frequency and temperature on microwave-induced
  magnetoresistance oscillations in two-dimensional electron systems

abstract:
  Experimental results on microwave-induced magnetoresistance oscillation in
two-dimensional electron systems show a similar behavior of these systems
regarding temperature and microwave frequency. It is found that these
oscillations tend to quench when frequency or temperature increase, approaching
magnetoresistance to the response of the dark system. In this work we show that
this experimental behavior can be addressed on the same theoretical basis.
Microwave radiation forces the electron orbits to move back and forth being
damped by interaction with the lattice. We show that this damping depends
dramatically on microwave frequency and also on temperature. An increase in
frequency or temperature gives rise to an increase in the lattice damping
producing eventually a quenching effect in the magnetoresistance oscillations.


title: Symmetries and exact solutions of the rotating shallow water equations

abstract:
  Lie symmetry analysis is applied to study the nonlinear rotating shallow
water equations. The 9-dimensional Lie algebra of point symmetries admitted by
the model is found. It is shown that the rotating shallow water equations are
related with the classical shallow water model with the change of variables.
The derived symmetries are used to generate new exact solutions of the rotating
shallow equations. In particular, a new class of time-periodic solutions with
quasi-closed particle trajectories is constructed and studied. The symmetry
reduction method is also used to obtain some invariant solutions of the model.
Examples of these solutions are presented with a brief physical interpretation.


title: The three-flavor chiral phase structure in hot and dense QCD matter

abstract:
  Chiral symmetry restoration at nonzero temperature and quark densities are
investigated in the framework of a linear sigma model with N_f=3 light quark
flavors. After the derivation of the grand potential in mean-field
approximation, the nonstrange and strange condensates, the in-medium masses of
the scalar and pseudoscalar nonets are analyzed in hot and dense medium. The
influence of the axial anomaly on the nonet masses and the isoscalar mixings on
the pseudoscalar \eta-\eta' and scalar \sigma(600)-f_0(1370) complex are
examined. The sensitivity of the chiral phase transition as well as the
existence and location of a critical end point in the phase diagram on the
value of the sigma mass is explored. The chiral critical surface with and
without the influence of the axial U(1)_A anomaly is elaborated as a function
of the pion and kaon masses for several values of the sigma mass.


title:
Giant fluctuations and gate control of the g-factor in InAs Nanowire
  Quantum Dots

abstract:
  We study the g-factor of discrete electron states in InAs nanowire based
quantum dots. The g values are determined from the magnetic field splitting of
the zero bias anomaly due to the spin 1/2-Kondo effect. Unlike to previous
studies based on 2DEG quantum dots, the g-factors of neighboring electron
states show a surprisingly large fluctuation: g can scatter between 2 and 18.
Furthermore electric gate tunability of the g-factor is demonstrated.


title: On Jordan type inequalities for hyperbolic functions

abstract:
  This paper deals with some inequalities for trigonometric and hyperbolic
functions such as the Jordan inequality and its generalizations. In particular,
lower and upper bounds for functions such as (sin x)/x and x/(sinh x) are
proved.


title:
Non-trivial length dependence of the conductance and negative
  differential resistance in atomic molecular wires

abstract:
  We study the electronic and transport properties of two novel molecular wires
made of atomic chains of carbon atoms (polyynes) capped with either,
benzene-thiols or pyridines. While both molecules are structurally similar, the
electrical conductance of benzene-thiol-capped chains attached to gold
electrodes is found to be much higher than that of pyridine-capped chains. We
predict that the conductance is almost independent of molecular length, which
suggests that these molecules could be ideal molecular wires for sub-10 nm
circuitry. Both systems exhibit negative differential resistance (NDR) but its
origin and characteristics depend on the type of molecule. We find a novel type
of NDR mechanism produced by the movement of the LUMO resonance with bias. We
also show that by gating the pyridine-capped molecules it is possible to make
the NDR disappear and dramatically modify the $I$-$V$ characteristics and the
length dependence.


title:
The finite harmonic oscillator and its applications to sequences,
  communication and radar

abstract:
  A novel system, called the oscillator system, consisting of order of p^3
functions (signals) on the finite field F_p; with p an odd prime, is described
and studied. The new functions are proved to satisfy good auto-correlation,
cross-correlation and low peak-to-average power ratio properties. Moreover, the
oscillator system is closed under the operation of discrete Fourier transform.
Applications of the oscillator system for discrete radar and digital
communication theory are explained. Finally, an explicit algorithm to construct
the oscillator system is presented.


title: Gluing Feynman diagrams in NDIM: Insights into the three-point vertex

abstract:
  Three-point vertex diagram plays a key role in the whole renormalization
program of several QFT (quantum field theory) models such as QED, QCD, the
Standard Model of eletroweak interactions and so forth. The exact analytic
result for the triangle diagram therefore is fundamental.
  In this work we calculate in two different ways a two-point two-loop massless
Feynman diagram using what we call a "gluing" technique in the context of NDIM
(Negative Dimensional Integration Method). The two-loop diagram in question can
be "glued" in two different ways and we show that both yield the same result
and reproduce the one calculated via NDIM for the complete diagram, which, of
course, is equivalent to the exact solution obtained by normal positive
dimensional calculation.
  Furthermore, in the process we conclude that the usual massless off-shell
triangle diagram result does not hold anymore and present a new solution for it
with only three hypergeometric functions $F_{4}$.


title: Boundary states and edge currents for free fermions

abstract:
  We calculate the ground state current densities for 2+1 dimensional free
fermion theories with local, translationally invariant boundary states.
Deformations of the bulk wave functions close to the edge and boundary states
both may cause edge current divergencies, which have to cancel in realistic
systems. This yields restrictions on the parameters of quantum field theories
which can arise as low energy limits of solid state systems. Some degree of
Lorentz invariance for boosts parallel to the boundary can be recovered, when
the cutoff is removed.


title:
Elliptic Cylindrical Invisibility Cloak, a Semianalytical Approach Using
  Mathieu Functions

abstract:
  An elliptic cylindrical wave expansion method by using Mathieu functions is
developed to obtain the scattering field for a two-dimensional elliptic
cylindrical invisibility cloak. The cloak material parameters are obtained from
the spatial transformation approach. A near-ideal model of the invisibility
cloak is set up to solve the boundary problem at the inner boundary in the
cloak shell. The proposed design provides a more practical cloak geometry when
compared to previous designs of elliptic cylindrical cloaks.


title: Two new Intermediate Polars with a soft X-ray component

abstract:
  We analyze the first X-ray observations with XMM-Newton of RXS
J070407.9+262501 and 1RXS 180340.0+401214, in order to characterize their
broad-band temporal and spectral properties, also in the UV/optical domain, and
to confirm them as Intermediate Polars. For both objects, we performed a timing
analysis of the X-ray and UV/optical light curves to detect the white dwarf
spin pulsations and study their energy dependence. For 1RXS 180340.0+401214 we
also analyzed optical spectroscopic data to determine the orbital period. X-ray
spectra were analyzed in the 0.2-10.0 keV range to characterize the emission
properties of both sources. We find that the X-ray light curves of both systems
are energy dependent and are dominated, below 3-5 keV, by strong pulsations at
the white dwarf rotational periods (480 s for 1RXS J070407.9+262501 and 1520.5
s for 1RXS 180340.0+401214). In 1RXS 180340.0+401214 we also detect an X-ray
beat variability at 1697 s which, together with our new optical spectroscopy,
favours an orbital period of 4.4 hr that is longer than previously estimated.
Both systems show complex spectra with a hard (up to 40 keV) optically thin and
a soft (85-100 eV) optically thick components heavily absorbed by material
partially covering the X-ray sources. Our observations confirm the two systems
as Intermediate Polars and also add them as new members of the growing group of
'soft' systems which show the presence of a soft X-ray blackbody component.
Differences in the temperatures of the blackbodies are qualitatively explained
in terms of reprocessing over different sizes of the white dwarf spot. We
suggest that systems showing cooler soft X-ray blackbody components also
possess white dwarfs irradiated by cyclotron radiation.


title: Cerenkov radiation of spinning particle

abstract:
  The Cerenkov radiation of a neutral particle with magnetic moment is
considered, as well as the spin-dependent contribution to the Cerenkov
radiation of a charged spinning particle. The corresponding radiation intensity
is obtained for an arbitrary value of spin and for an arbitrary spin
orientation with respect to velocity.


title:
Genuine phase diffusion of a Bose-Einstein condensate in the
  microcanonical ensemble: A classical field study

abstract:
  Within the classical field model, we find that the phase of a Bose-Einstein
condensate undergoes a true diffusive motion in the microcanonical ensemble,
the variance of the condensate phase change between time zero and time $t$
growing linearly in $t$. The phase diffusion coefficient obeys a simple scaling
law in the double thermodynamic and Bogoliubov limit. We construct an
approximate calculation of the diffusion coefficient, in fair agreement with
the numerical results over the considered temperature range, and we extend this
approximate calculation to the quantum field.


title: Circular Law Theorem for Random Markov Matrices

abstract:
  Consider an nxn random matrix X with i.i.d. nonnegative entries with bounded
density, mean m, and finite positive variance sigma^2. Let M be the nxn random
Markov matrix with i.i.d. rows obtained from X by dividing each row of X by its
sum. In particular, when X11 follows an exponential law, then M belongs to the
Dirichlet Markov Ensemble of random stochastic matrices. Our main result states
that with probability one, the counting probability measure of the complex
spectrum of n^(1/2)M converges weakly as n tends to infinity to the uniform law
on the centered disk of radius sigma/m. The bounded density assumption is
purely technical and comes from the way we control the operator norm of the
resolvent.


title:
Significance of a combined approach for replacement stones in the
  heritage buildings' conservation frame

abstract:
  Stone substitution is a conventional operation during heritage buildings'
restoration, but becomes problematic for architects and restorers when the
quarry is mined out. The compatibility of the substitution stones with the
original ones has been for long mainly based on the aesthetical aspect, this
resulting too often in a patchwork of original and substitution stones with
different patina after several years because of differences of properties. In
this study, the objective is to show how substitution stones can be selected by
combining aesthetic criteria and stones properties that are relevant for
analyzing their compatibility. A couple of French limestones with their
potential substitution stones were selected for the study. Our results showed
that potential substitution stones selected on their aesthetic criteria require
to be rejected because of their differences of physical properties. On the
other hand, our results showed also the possibility to select substitution
stones with satisfactory aesthetic aspect and properties that enable to expect
a satisfactory compatibility with the original stone.


title: Open and hidden charm in proton-nucleus and heavy-ion collisions

abstract:
  We review the collectivity and the suppression pattern of charmed mesons -
produced in proton-nucleus and nucleus-nucleus collisions at SPS (158 AGeV) and
RHIC energies (21 ATeV) - in comparison to dynamical and thermal models. In
particular, we examine the charmonium `melting' and the `comover dissociation'
scenarios - implemented in a microscopic transport approach - in comparison to
the available data from the SPS and RHIC. The analysis shows that the dynamics
of c, c-bar quarks at RHIC are dominated by partonic or `pre-hadronic'
interactions in the strongly coupled plasma stage. Both the `charmonium
melting' and the hadronic `comover absorption and recreation model' are found,
however, to be compatible with the experimental observation at SPS energies;
the experimental ratio of Psi'/J/Psi versus centrality clearly favors the
`hadronic comover' scenario. We find that the collective flow of charm in the
purely hadronic Hadron-String Dynamics (HSD) transport appears compatible with
the data at SPS energies, but substantially underestimates the data at top RHIC
energies. Thus, the large elliptic flow v2 of D-mesons and the low R_AA(p_T) of
J/Psi seen experimentally have to be attributed to early interactions of
non-hadronic degrees of freedom. Simultaneously, we observe that non-hadronic
interactions are mandatory in order to describe the narrowing of the J/Psi
rapidity distribution from pp to central Au+Au collisions at the top RHIC
energy. We demonstrate additionally that the strong quenching of low-pT J/Psi's
in central Au+Au collisions indicates that a large fraction of final J/Psi
mesons is created by a coalescence mechanism close to the phase boundary.
Throughout this review we, furthermore, provide predictions for charm
observables from Au+Au collisions at FAIR energies of 25-35 AGeV.


title:
An Almost-Surely Terminating Polynomial Protocol for Asynchronous
  Byzantine Agreement with Optimal Resilience

abstract:
  Consider an asynchronous system with private channels and $n$ processes, up
to $t$ of which may be faulty. We settle a longstanding open question by
providing a Byzantine agreement protocol that simultaneously achieves three
properties:
  1. (optimal) resilience: it works as long as $n>3t$
  2. (almost-sure) termination: with probability one, all nonfaulty processes
terminate
  3. (polynomial) efficiency: the expected computation time, memory
consumption, message size, and number of messages sent are all polynomial in
$n$.
  Earlier protocols have achieved only two of these three properties. In
particular, the protocol of Bracha is not polynomially efficient, the protocol
of Feldman and Micali is not optimally resilient, and the protocol of Canetti
and Rabin does not have almost-sure termination. Our protocol utilizes a new
primitive called shunning (asynchronous) verifiable secret sharing (SVSS),
which ensures, roughly speaking, that either a secret is successfully shared or
a new faulty process is ignored from this point onwards by some nonfaulty
process.


title:
Magnetic dipolar interaction in an atomic Bose Einstein condensate
  interferometer

abstract:
  We study the role played by the magnetic dipole interaction in an atomic
interferometer based on an alkali Bose-Einstein condensate with tunable
scattering length. We tune the s-wave interaction to zero using a magnetic
Feshbach resonance and measure the decoherence of the interferometer induced by
the weak residual interaction between the magnetic dipoles of the atoms. We
prove that with a proper choice of the scattering length it is possible to
compensate for the dipolar interaction and extend the coherence time of the
interferometer. We put in evidence the anisotropic character of the dipolar
interaction by working with two different experimental configurations for which
the minima of decoherence are achieved for a positive and a negative value of
the scattering length, respectively. Our results are supported by a theoretical
model we develop. This model indicates that the magnetic dipole interaction
should not represent a serious source of decoherence in atom interferometers
based on Bose-Einstein condensates.


title: New results on the least common multiple of consecutive integers

abstract:
  When studying the least common multiple of some finite sequences of integers,
the first author introduced the interesting arithmetic functions $g_k$ $(k \in
\mathbb{N})$, defined by $g_k(n) := \frac{n (n + 1) ... (n + k)}{\lcm(n, n + 1,
>..., n + k)}$ $(\forall n \in \mathbb{N} \setminus \{0\})$. He proved that
$g_k$ $(k \in \mathbb{N})$ is periodic and $k!$ is a period of $g_k$. He raised
the open problem consisting to determine the smallest positive period $P_k$ of
$g_k$. Very recently, S. Hong and Y. Yang have improved the period $k!$ of
$g_k$ to $\lcm(1, 2, ..., k)$. In addition, they have conjectured that $P_k$ is
always a multiple of the positive integer $\frac{\lcm(1, 2, >..., k, k + 1)}{k
+ 1}$. An immediate consequence of this conjecture states that if $(k + 1)$ is
prime then the exact period of $g_k$ is precisely equal to $\lcm(1, 2, ...,
k)$.
  In this paper, we first prove the conjecture of S. Hong and Y. Yang and then
we give the exact value of $P_k$ $(k \in \mathbb{N})$. We deduce, as a
corollary, that $P_k$ is equal to the part of $\lcm(1, 2, ..., k)$ not
divisible by some prime.


title:
Comparison between CPBPV, ESC/Java, CBMC, Blast, EUREKA and Why for
  Bounded Program Verification

abstract:
  This report describes experimental results for a set of benchmarks on program
verification. It compares the capabilities of CPBVP "Constraint Programming
framework for Bounded Program Verification" [4] with the following frameworks:
ESC/Java, CBMC, Blast, EUREKA and Why.


title:
Regular dependence on initial data for stochastic evolution equations
  with multiplicative Poisson noise

abstract:
  We prove existence, uniqueness and Lipschitz dependence on the initial datum
for mild solutions of stochastic partial differential equations with Lipschitz
coefficients driven by Wiener and Poisson noise. Under additional assumptions,
we prove Gateaux and Frechet differentiability of solutions with respect to the
initial datum. As an application, we obtain gradient estimates for the
resolvent associated to the mild solution. Finally, we prove the strong Feller
property of the associated semigroup.


title: The effect of stellar winds on the formation of a protocluster

abstract:
  We present SPH simulations of protoclusters including the effects of winds
from massive stars. Using a particle-injection method, we investigate the
effect of structure close to the wind sources and the short-timescale influence
of winds on protoclusters. Structures such as disks and gaseous filaments have
a strong collimating effect. By a different technique of injecting momentum
from point sources, we compare the large-scale, long-term effects of isotropic
and intrinsically-collimated winds and find them to be similar. Both types of
wind dramatically slow the global star formation process, but the timescale on
which they expel significant mass from the cluster is rather long (approaching
10 freefall times). Clusters may then experience rapid star formation early in
their lifetimes, before switching to a mode where gas is gradually expelled,
while star formation proceeds much more slowly. This complicates conclusions
regarding slow star formation derived from measuring the star-formation
efficiency per freefall time. Estimates of the efficacy of winds in dispersing
clusters derived simply from the total wind momentum flux may not be very
reliable. This is due to material being expelled from deep within stellar
potential wells, often to velocities well in excess of the cluster escape
velocity, and also to the loss of momentum flux through holes in the gas
distribution. Winds have little effect on the accretion--driven stellar IMF
except at the very high-mass end, where they serve to prevent some of the most
massive objects accreting. We also find that the morphology of the gas, the
rapid motions of the wind sources and the action of accretion flows prevent the
formation of bubble-like structures. This may make it difficult to discern the
influence of winds on very young clusters.


title:
A mathematical interpretation of the Feynman path integral equivalent to
  the formalism of Green functions

abstract:
  We define the notion of distribution on an infinite dimensional space
motivated by the notion of Feynman path integral and by construction of
probability measures for generalized random fields. This notion of distribution
turns out to be mathematically equivalent to the notion of generating
functional of Green functions.


title: The Electroweak Phase Transition in Nearly Conformal Technicolor

abstract:
  We examine the temperature-dependent electroweak phase transition in
extensions of the Standard Model in which the electroweak symmetry is
spontaneously broken via strongly coupled, nearly-conformal dynamics. In
particular, we focus on the low energy effective theory used to describe
Minimal Walking Technicolor at the phase transition. Using the one-loop
effective potential with ring improvement, we identify significant regions of
parameter space which yield a sufficiently strong first order transition for
electroweak baryogenesis. The composite particle spectrum corresponding to
these regions can be produced and studied at the Large Hadron Collider
experiment. We note the possible emergence of a second phase transition at
lower temperatures. This occurs when the underlying technicolor theory
possesses a nontrivial center symmetry.


title: Optimal Markov Approximations and Generalized Embeddings

abstract:
  Based on information theory, we present a method to determine an optimal
Markov approximation for modelling and prediction from time series data. The
method finds a balance between minimal modelling errors by taking as much as
possible memory into account and minimal statistical errors by working in
embedding spaces of rather small dimension. A key ingredient is an estimate of
the statistical error of entropy estimates. The method is illustrated with
several examples and the consequences for prediction are evaluated by means of
the root mean squard prediction error for point prediction.


title: Shape waves in 2D Josephson junctions: exact solutions and time dilation

abstract:
  We predict a new class of excitations propagating along a Josephson vortex in
two-dimensional Josephson junctions. These excitations are associated with the
distortion of a Josephson vortex line and have an analogy with shear waves in
solid mechanics. Their shapes can have an arbitrary profile, which is retained
when propagating. We derive a universal analytical expression for the energy of
arbitrary shape excitations, investigate their influence on the dynamics of a
vortex line, and discuss conditions where such excitations can be created.
Finally, we show that such excitations play the role of a clock for a
relativistically-moving Josephson vortex and suggest an experiment to measure a
time dilation effect analogous to that in special relativity.


title:
On the application of homotopy--perturbation and Adomian decomposition
  methods to the linear and nonlinear Schr\"{o}dinger equations

abstract:
  I discuss a recent application of homotopy perturbation and Adomian
decomposition methods to the linear and nonlinear Schr\"odinger equations. I
propose a generalization of the procedure for the treatment of a wider class of
problems.


title:
Anomalous Josephson Current in Junctions with Spin-Polarizing Quantum
  Point Contacts

abstract:
  We consider a ballistic Josephson junction with a quantum point contact in a
two-dimensional electron gas with Rashba spin-orbit coupling. The point contact
acts as a spin filter when embedded in a circuit with normal electrodes. We
show that with an in-plane external magnetic field an anomalous supercurrent
appears even for zero phase difference between the superconducting electrodes.
In addition, the external field induces large critical current asymmetries
between the two flow directions, leading to supercurrent rectifying effects.


title:
The power of multifolds: Folding the algebraic closure of the rational
  numbers

abstract:
  It is well known that the usual Huzita-Hatori axioms for origami enable angle
trisection but not angle quintisection. Using the concept of a multifold, Lang
has achieved quintisection but not arbitrary algebraic numbers. We define the
n-parameter multifold and show how to use one-parameter multifolds to obtain
the algebraic closure of the rational numbers.


title: Constructive Gelfand duality for C*-algebras

abstract:
  We present a constructive proof of Gelfand duality for C*-algebras by
reducing the problem to Gelfand duality for real C*-algebras.


title: De Morgan classifying toposes

abstract:
  We present a general method for deciding whether a Grothendieck topos
satisfies De Morgan's law (resp. the law of excluded middle) or not;
applications to the theory of classifying toposes follow. Specifically, we
obtain a syntactic characterization of the class of geometric theories whose
classifying toposes satisfy De Morgan's law (resp. are Boolean), as well as
model-theoretic criteria for theories whose classifying toposes arise as
localizations of a given presheaf topos.


title:
Resonant excitations of single and two-qubit systems coupled to a tank
  circuit

abstract:
  The interaction of flux qubits with a low frequency tank circuit is studied.
It is shown that changes in the state of the interacting qubits influence the
effective impedance of the circuit, which is the essence of the so-called
impedance measurement technique. The multiphoton resonant excitations in both
single flux qubits and pairs of coupled flux qubits are investigated. In
particular, we compare our theoretical results with recent spectroscopy
measurements, Landau-Zener interferometry, and multiphoton fringes.


title: Radial kinematics of brightest cluster galaxies

abstract:
  This is the first of a series of papers devoted to the investigation of a
large sample of brightest cluster galaxies (BCGs), their kinematic and stellar
population properties, and the relationships between those and the properties
of the cluster. We have obtained high signal-to-noise ratio, long-slit spectra
of these galaxies with Gemini and WHT with the primary purpose of investigating
their stellar population properties. This paper describes the selection methods
and criteria used to compile a new sample of galaxies, concentrating on BCGs
previously classified as containing a halo (cD galaxies), together with the
observations and data reduction. Here, we present the full sample of galaxies,
and the measurement and interpretation of the radial velocity and velocity
dispersion profiles of 41 BCGs. We find clear rotation curves for a number of
these giant galaxies. In particular, we find rapid rotation (> 100 km/s) for
two BCGs, NGC6034 and NGC7768, indicating that it is unlikely that they formed
through dissipationless mergers. Velocity substructure in the form of
kinematically decoupled cores is detected in 12 galaxies, and we find five
galaxies with velocity dispersion increasing with radius. The amount of
rotation, the velocity substructure and the position of BCGs on the
anisotropy-luminosity diagram are very similar to those of "ordinary" giant
ellipticals in high density environments.


title: Integrals and Valuations

abstract:
  We construct a homeomorphism between the compact regular locale of integrals
on a Riesz space and the locale of (valuations) on its spectrum. In fact, we
construct two geometric theories and show that they are biinterpretable. The
constructions are elementary and tightly connected to the Riesz space
structure.


title:
Two-loop neutrino masses with large R-parity violating interactions in
  supersymmetry

abstract:
  We attempt to reconcile large trilinear R-parity violating interactions in a
supersymmetric (SUSY) theory with the observed pattern of neutrino masses and
mixing. We show that, with a restricted number of such interaction terms with
the $\lambda'$-type couplings in the range (0.1-1.0), it is possible to forbid
one-loop contributions to the neutrino mass matrix. This is illustrated with
the help of a `working example' where an econnomic choice of SUSY parameters is
made, with three non-vanishing and `large' R-parity violating terms in the
superpotential. The two-loop contributions in such a case can not only generate
the masses in the requisite order but can also lead us to specific allowed
regions of the parameter space.


title:
High-Frequency Microstrip Cross Resonators for Circular Polarization EPR
  Spectroscopy

abstract:
  In this article we discuss the design and implementation of a novel
microstrip resonator which allows for the absolute control of the microwaves
polarization degree for frequencies up to 30 GHz. The sensor is composed of two
half-wavelength microstrip line resonators, designed to match the 50 Ohms
impedance of the lines on a high dielectric constant GaAs substrate. The line
resonators cross each other perpendicularly through their centers, forming a
cross. Microstrip feed lines are coupled through small gaps to three arms of
the cross to connect the resonator to the excitation ports. The control of the
relative magnitude and phase between the two microwave stimuli at the input
ports of each line allows for tuning the degree and type of polarization of the
microwave excitation at the center of the cross resonator. The third (output)
port is used to measure the transmitted signal, which is crucial to work at low
temperatures, where reflections along lengthy coaxial lines mask the signal
reflected by the resonator. EPR spectra recorded at low temperature in an S=
5/2 molecular magnet system show that 82%-fidelity circular polarization of the
microwaves is achieved over the central area of the resonator.


title: Bounding sup-norms of cusp forms of large level

abstract:
  Let f be an $L^2$-normalized weight zero Hecke-Maass cusp form of square-free
level N, character $\chi$ and Laplacian eigenvalue $\lambda\geq 1/4$. It is
shown that $\| f \|_{\infty} \ll_{\lambda} N^{-1/37}$, from which the hybrid
bound $\|f \|_{\infty} \ll \lambda^{1/4} (N\lambda)^{-\delta}$ (for some
$\delta > 0$) is derived. The first bound holds also for $f = y^{k/2}F$ where F
is a holomorphic cusp form of weight k with the implied constant now depending
on k.


title:
Comment on "Gauge Invariance and $k_T$-Factorization of Exclusive
  Processes"

abstract:
  We point out mistakes made in the one-loop calculation of some diagrams for
the process $\pi \gamma^* \to \gamma$ in the preprint arXiv:0807.0296, and
present correct results. Especially, we have difficulty to understand their
argument that a highly off-shell gluon generates a light-cone (infrared)
singularity. It is shown by means of the Ward identity that the gauge-dependent
light-cone singularity found in arXiv:0807.0296 does not exist. It is then
shown that a hard kernel derived in the $k_T$ factorization of exclusive
processes is gauge invariant and free of the light-cone singularity.


title: An alternative parameterisation for binary-lens caustic-crossing events

abstract:
  Microlensing events are being discovered and alerted by the two survey teams
OGLE and MOA at an increasing rate. Around ten percent of these events involve
binary lenses. Such events potentially contain much information on the physical
properties of the observed binary systems, which can then be used for e.g.
statistical studies on binary objects in the Galactic disk or bulge. However,
such events are usually not straightforward to study, because the model
equations are strongly non-linear and there are many local minima that can fool
the search for the best solution if the parameter space is not inspected with
great care. In this work an alternative parameterisation for the binary lens
fitting problem is proposed, in which the parameters involved are defined to
represent as closely as possible the caustic-crossing features observed in most
binary lens light curves. Furthermore, we work out an extension of the method
in order to make use of the straight line fold caustic approximation, when the
latter applies for both the caustic entry and exit. We introduce an alternative
parameterisation in order to confine the exploration of the parameter space to
regions where the models only involve caustic crossing at the dates seen in the
light curve. We find that the proposed parameterisation provides more
robustness to the light curve fitting process, in particular in avoiding a code
to get stuck in false minima.


title: Eigenvalue Asymptotics in a Twisted Waveguide

abstract:
  We consider a twisted quantum wave guide, and are interested in the spectral
analysis of the associated Dirichlet Laplacian H. We show that if the
derivative of rotation angle decays slowly enough at infinity, then there is an
infinite sequence of discrete eigenvalues lying below the infimum of the
essential spectrum of H, and obtain the main asymptotic term of this sequence.


title: On the complexity group of stable curves

abstract:
  In this paper, we study combinatorial properties of stable curves. To the
dual graph of any nodal curve, it is naturally associated a group, which is the
group of components of the N\'eron model of the generalized Jacobian of the
curve. We study the order of this group, called the complexity. In particular,
we provide a partial characterization of the stable curves having maximal
complexity, and we provide an upper bound, depending only on the genus $g$ of
the curve, on the maximal complexity of stable curves; this bound is
asymptotically sharp for $g\gg 0$. Eventually, we state some conjectures on the
behavior of stable curves with maximal complexity, and prove partial results in
this direction.


title:
Tan(beta)-enhanced supersymmetric corrections to the anomalous magnetic
  moment of the muon

abstract:
  We report on a two-loop supersymmetric contribution to the magnetic moment
(g-2)_mu of the muon which is enhanced by two powers of tan(beta). This
contribution arises from a shift in the relation between the muon mass and
Yukawa coupling and can increase the supersymmetric contribution to (g-2)_mu
sizably. As a result, if the currently observed 3 sigma deviation between the
experimental and SM theory value of (g-2)_mu is analyzed within the Minimal
Supersymmetric Standard Model (MSSM), the derived constraints on the parameter
space are modified significantly: If (g-2)_mu is used to determine tan(beta) as
a function of the other MSSM parameters, our corrections decrease tan(beta) by
roughly 10% for tan(beta)=50.


title: A statistical approximation to solve ordinary differential equations

abstract:
  We propose a physical analogy between finding the solution of an ordinary
differential equation (ODE) and a $N$ particle problem in statistical
mechanics. It uses the fact that the solution of an ODE is equivalent to obtain
the minimum of a functional. Then, we link these two notions, proposing this
functional to be the interaction potential energy or thermodynamic potential of
an equivalent particle problem. Therefore, solving this statistical mechanics
problem amounts to solve the ODE. If only one solution exists, our method
provides the unique solution of the ODE. In case we treat an eigenvalue
equation, where infinite solutions exist, we obtain the absolute minimum of the
corresponding functional or fundamental mode. As a result, it is possible to
establish a general relationship between statistical mechanics and ODEs which
allows not only to solve them from a physical perspective but also to obtain
all relevant thermodynamical equilibrium variables of that particle system
related to the differential equation.


title: Graph States for Quantum Secret Sharing

abstract:
  We consider three broad classes of quantum secret sharing with and without
eavesdropping and show how a graph state formalism unifies otherwise disparate
quantum secret sharing models. In addition to the elegant unification provided
by graph states, our approach provides a generalization of threshold classical
secret sharing via insecure quantum channels beyond the current requirement of
100% collaboration by players to just a simple majority in the case of five
players. Another innovation here is the introduction of embedded protocols
within a larger graph state that serves as a one-way quantum information
processing system.


title: The third order helicity of magnetic fields via link maps

abstract:
  We introduce an alternative approach to the third order helicity of a volume
preserving vector field $B$, which leads us to a lower bound for the
$L^2$-energy of $B$. The proposed approach exploits correspondence between the
Milnor $\bar{\mu}_{123}$-invariant for 3-component links and the homotopy
invariants of maps to configuration spaces, and we provide a simple geometric
proof of this fact in the case of Borromean links. Based on these connections
we develop a formulation for the third order helicity of $B$ on invariant
\emph{unlinked} domains of $B$, and provide Arnold's style ergodic
interpretation of this invariant as an average asymptotic
$\bar{\mu}_{123}$-invariant of orbits of $B$.


title: The derivative nonlinear Schr\"odinger equation on the half-line

abstract:
  We analyze the derivative nonlinear Schr\"odinger equation $iq_t + q_{xx} =
i(|q|^2q)_x$ on the half-line using the Fokas method. Assuming that the
solution $q(x,t)$ exists, we show that it can be represented in terms of the
solution of a matrix Riemann-Hilbert problem formulated in the plane of the
complex spectral parameter $\zeta$. The jump matrix has explicit $x,t$
dependence and is given in terms of the spectral functions $a(\zeta)$,
$b(\zeta)$ (obtained from the initial data $q_0(x) = q(x,0)$) as well as
$A(\zeta)$, $B(\zeta)$ (obtained from the boundary values $g_0(t) = q(0,t)$ and
$g_1(t) = q_x(0,t)$). The spectral functions are not independent, but related
by a compatibility condition, the so-called global relation. Given initial and
boundary values $\{q_0(x), g_0(t), g_1(t)\}$ such that there exist spectral
function satisfying the global relation, we show that the function $q(x,t)$
defined by the above Riemann-Hilbert problem exists globally and solves the
derivative nonlinear Schr\"odinger equation with the prescribed initial and
boundary values.


title: Nonabelian Generalized Gauge Multiplets

abstract:
  We give the nonabelian extension of the newly discovered N = (2, 2)
two-dimensional vector multiplets. These can be used to gauge symmetries of
sigma models on generalized Kahler geometries. Starting from the transformation
rule for the nonabelian case we find covariant derivatives and gauge covariant
field-strengths and write their actions in N = (2, 2) and N = (1, 1)
superspace.


title: Direct observation of quantum criticality in Ising spin chains

abstract:
  We use NMR quantum simulators to study antiferromagnetic Ising spin chains
undergoing quantum phase transitions. Taking advantage of the sensitivity of
the systems near criticality, we detect the critical points of the transitions
using a direct measurement of the Loschmidt echo. We test our simulators for
spin chains of even and odd numbers of spins, and compare the experimental
results to theoretical predictions.


title: On Spectral Gap,U(1) Symmetry and Split Property in Quantum Spin Chains

abstract:
  We consider a class of ground states for quantum spin chains on an integer
lattice. First we show that presence of the spectral gap between the ground
state energy and the rest of spectrum implies the split property of certain
subsystems.As a corollary, we show that gapless excitation exists for spinless
Fermion if the pure gauge invariant ground state is non-trivial and
translationally invariant.


title:
Heterogeneous expectations and long range correlation of the volatility
  of asset returns

abstract:
  Inspired by the recent literature on aggregation theory, we aim at relating
the long range correlation of the stocks return volatility to the heterogeneity
of the investors' expectations about the level of the future volatility. Based
on a semi-parametric model of investors' anticipations, we make the connection
between the distributional properties of the heterogeneity parameters and the
auto-covariance/auto-correlation functions of the realized volatility. We
report different behaviors, or change of convention, whose observation depends
on the market phase under consideration. In particular, we report and justify
the fact that the volatility exhibits significantly longer memory during the
phases of speculative bubble than during the phase of recovery following the
collapse of a speculative bubble.


title:
The kinetic temperature of a molecular cloud at redshift 0.9: Ammonia in
  the gravitational lens PKS1830-211

abstract:
  Using the Green Bank Telescope (GBT), we have detected the (J,K) = (1,1) to
(10,10) ammonia inversion lines, up to 1030 K above the ground state, in a
face-on spiral galaxy viewed against the radio continuum of the lensed
background source PKS 1830-211. The ammonia absorption lines, seen at redshift
0.886, appear to be optically thin with absolute peak flux densities up to 2.5
percent of the total continuum of the background source. Measured intensities
are consistent with a kinetic temperature of 80 K for 80-90 percent of the
ammonia column. The remaining gas is warmer, reaching at least 600 K. Column
density and fractional abundance are of order (5-10) x 10^14 cm^-2 and
(1.5-3.0) x 10^-8. Similarities with a hot ammonia absorption component
observed toward the Sgr B2 region close to the Galactic center may suggest that
the Sgr B2 component also originates from warm diffuse low-density molecular
gas. The warm ammonia column observed toward PKS 1830-211 is unique in the
sense that it originates in a spiral arm.


title:
The magnetic field and the location of the TeV emitter in Cygnus X-1 and
  LS 5039

abstract:
  Cygnus X-1 and LS 5039 are two X-ray binaries observed at TeV energies. Both
sources are compact systems, contain jet-like (radio) structures, and harbor
very luminous O stars. A TeV signal has been found around the superior
conjunction of the compact object in both objects, when the highest gamma-ray
opacities are expected. We investigate the implications of finding TeV emission
from Cygnus X-1 and LS 5039 around the superior conjunction, since this can
give information on the system magnetic field and the location of the TeV
emitter. Using the very high-energy spectra and fluxes observed around the
superior conjunction in Cygnus X-1 and LS 5039, we compute the absorbed
luminosity that is caused by pair creation in the stellar photon field for
different emitter positions with respect to the star and the observer line of
sight. The role of the magnetic field and electromagnetic cascading are
discussed. For the case of inefficient electromagnetic cascading, the expected
secondary synchrotron fluxes are compared with the observed ones at X-ray
energies. We find that, in Cygnus X-1 and LS 5039, either the magnetic field in
the star surroundings is much smaller than the one expected for O stars or the
TeV emitter is located at a distance >10^12 cm from the compact object. Our
results strongly suggest that the TeV emitters in Cygnus X-1 and LS 5039 are
located at the borders of the binary system and well above the orbital plane.
This would not agree with those models for which the emitter is well inside the
system, like the innermost-jet region (Cygnus X-1 and LS 5039; microquasar
scenario), or the region between the pulsar and the primary star (LS 5039;
standard pulsar scenario).


title:
About the inconsistency between Bohr-Wheelers transition-state method
  and Kramers' escape rate in nuclear fission

abstract:
  The problem of an apparent inconsistency between the fission rates derived on
the basis of Bohr-Wheeler's transition-state method and Kramers' dynamical
model of nuclear fission, first pointed out by Strutinsky in 1973, is
revisited. The study is based on studying the features of individual
trajectories on the fission path.


title: Tevatron Electron Lenses: Design and Operation

abstract:
  The beam-beam effects have been the dominating sources of beam loss and
lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron
lenses were originally proposed for compensation of electromagnetic long-range
and head-on beam-beam interactions of proton and antiproton beams [2]. Results
of successful employment of two electron lenses built and installed in the
Tevatron are reported in [3,4,5]. In this paper we present design features of
the Tevatron electron lenses (TELs), discuss the generation of electron beams,
describe different modes of operation and outline the technical parameters of
various subsystems.


title:
Study of the pi+pi-J/psi Mass Spectrum via Initial-State Radiation at
  BABAR

abstract:
  We present an update of the study of the Y(4260) resonance, produced in the
process $e^+e^-\to\gamma_{ISR} \pi^+\pi^-J/\psi$ using initial-state radiation
events at the PEP-II $e^+e^-$ storage rings. This study is based on
454fb$^{-1}$ of data recorded with the {\slshape B\kern-0.1em{\smaller
A}\kern-0.1em B\kern-0.1em{\smaller A\kern-0.2em R}} detector at a
center-of-mass energy in the $\Upsilon(4S)$ resonance region. From a fit with a
single non-relativistic Breit-Wigner shape we obtain updated parameters for the
Y(4260) resonance which are $m_Y = 4252 \pm6 ^{+2}_{-3}$MeV/c$^2$ and $\Gamma_Y
= 105 \pm 18^{+4}_{-6}$MeV/c$^2$; we also measure
${\calB}(\pi^+\pi^-J/\psi)\Gamma_{e^+e^-} = (7.5\pm 0.9 \pm0.8)$ eV. We cannot
confirm the recent BELLE observation of a broad structure around 4.05GeV/c$^2$
in this decay mode.


title: Muon Capture on the Proton and Deuteron

abstract:
  By measuring the lifetime of the negative muon in pure protium (hydrogen-1),
the MuCap experiment determines the rate of muon capture on the proton, from
which the proton's pseudoscalar coupling g_p may be inferred. A precision of
15% for g_p has been published; this is a step along the way to a goal of 7%.
This coupling can be calculated precisely from heavy baryon chiral perturbation
theory and therefore permits a test of QCD's chiral symmetry. Meanwhile, the
MuSun experiment is in its final design stage; it will measure the rate of muon
capture on the deuteron using a similar technique. This process can be related
through pionless effective field theory and chiral perturbation theory to other
two-nucleon reactions of astrophysical interest, including proton-proton fusion
and deuteron breakup.


title: Flares as fingerprints of inner solar darkness

abstract:
  X-ray flares and other solar brightenings have been discarded as potential
axion signatures. An axion X-ray signal must appear exclusively near the disk
centre, and its spectrum must peak at ~4.2keV, contrary to observation. We
argue here that due to Compton scattering off the (plasma) electrons the
outward propagation of X-rays from axions converted near the Sun's surface can
explain energy distribution and non direcivity. Simulation points at the
photosphere as the birth place of the presumed axion conversion, implying an
axion rest mass of ~0.01eV. At present, even optimistic parameter values can
not reproduce the measured intensities. The simulated photon spectrum peaks at
low energies. Quiet Sun hard X-rays are in favour of massive and/or light axion
involvement.


title:
The Study of Entangled States in Quantum Computation and Quantum
  Information Science

abstract:
  This thesis explores the use of entangled states in quantum computation and
quantum information science. Entanglement, a quantum phenomenon with no
classical counterpart, has been identified as an important and quantifiable
resource in many areas of theoretical quantum information science, including
quantum error correction, quantum cryptography, and quantum algorithms. We
first investigate the equivalence classes of a particular class of entangled
states (known as graph states due to their association with mathematical
graphs) under local operations. We prove that for graph states corresponding to
graphs with neither cycles of length 3 nor 4, the equivalence classes can be
characterized in a very simple way. We also present software for analyzing and
manipulating graph states. We then study quantum error-correcting codes whose
codewords are highly entangled states. An important area of investigation
concerning QECCs is to determine which resources are necessary in order to
carry out any computation on the code to an arbitrary degree of accuracy, while
simultaneously maintaining a high degree of resistance to noise. We prove that
transversal gates, which are designed to prevent the propagation of errors
through a system, are insufficient to achieve universal computation on almost
all QECCs. Finally, we study the problem of creating efficient quantum circuits
for creating entangling measurements. Entangling measurements can be used to
harness the apparent extra computing power of quantum systems by allowing us to
extract information about the global, collective properties of a quantum state
using local measurements. We construct explicit quantum circuits that create
entangling measurements, and show that these circuits scale polynomially in the
input parameters.


title: Integration with Functions of a Quaternionic Variable

abstract:
  Recent innovations in the differential calculus for functions of
non-commuting variables, beginning with a quaternionic variable, are now
extended to consider some integration.


title: Vortices near the Mott phase of a trapped Bose-Einstein condensate

abstract:
  We present a theoretical study of vortices within a harmonically trapped
Bose-Einstein condensate in a rotating optical lattice. We find that proximity
to the Mott insulating state dramatically effects the vortex structures. To
illustrate we give examples in which the vortices: (i) all sit at a fixed
distance from the center of the trap, forming a ring, or (ii) coalesce at the
center of the trap, forming a giant vortex. We model time-of-flight expansion
to demonstrate the experimental observability of our predictions.


title: The Peculiar Phase Structure of Random Graph Bisection

abstract:
  The mincut graph bisection problem involves partitioning the n vertices of a
graph into disjoint subsets, each containing exactly n/2 vertices, while
minimizing the number of "cut" edges with an endpoint in each subset. When
considered over sparse random graphs, the phase structure of the graph
bisection problem displays certain familiar properties, but also some
surprises. It is known that when the mean degree is below the critical value of
2 log 2, the cutsize is zero with high probability. We study how the minimum
cutsize increases with mean degree above this critical threshold, finding a new
analytical upper bound that improves considerably upon previous bounds.
Combined with recent results on expander graphs, our bound suggests the unusual
scenario that random graph bisection is replica symmetric up to and beyond the
critical threshold, with a replica symmetry breaking transition possibly taking
place above the threshold. An intriguing algorithmic consequence is that
although the problem is NP-hard, we can find near-optimal cutsizes (whose ratio
to the optimal value approaches 1 asymptotically) in polynomial time for
typical instances near the phase transition.

categories: cond-mat.stat-mech cond-mat.dis-nn cs.CC cs.DM


title: Smoothable del Pezzo surfaces with quotient singularities

abstract:
  We give a complete classification of del Pezzo surfaces with quotient
singularities and Picard rank 1 which admit a Q-Gorenstein smoothing.
  There are 14 infinite families of toric examples. The surfaces in each family
correspond to solutions of a Markov-type equation. The remaining surfaces are
obtained as deformations of the toric surfaces or belong to a finite list of
sporadic surfaces.


title: On SYZ mirror transformations

abstract:
  In this expository paper, we discuss how Fourier-Mukai-type transformations,
which we call SYZ mirror transformations, can be applied to provide a geometric
understanding of the mirror symmetry phenomena for semi-flat Calabi-Yau
manifolds and toric Fano manifolds. We also speculate the possible applications
of these transformations to other more general settings.


title: Note on the thermal history of decoupled massive particles

abstract:
  This note provides an alternative approach to the momentum decay and thermal
evolution of decoupled massive particles. Although the ingredients in our
results have been addressed in Ref.\cite{Weinberg}, the strategies employed
here are simpler, and the results obtained here are more general.


title: Remark on quantum mechanics with conformal Galilean symmetry

abstract:
  Conformal Galilei algebra contains so(1,2) subalgebra which is the conformal
algebra in one dimension. In this note we generalize methods previously
developed for one-dimensional many-body systems and construct a unitary map
relating a quantum mechanics invariant under the conformal Galilean
transformations to a set of decoupled particles for which the same symmetry is
realized in a nonlocal way. Possible applications of the map are discussed.


title: Long wavelength limit of two dimensional photonic crystals

abstract:
  We solve {\bf analytically} the multiple scattering (KKR) equations for the
two dimensional photonic crystals in the long wavelength limit. Different
approximations of the electric and magnetic susceptibilities are presented from
a unified pseudopotential point of view. The nature of the so called
plasmon-polariton bands are clarified. Its frequency as a function of the wire
radius is discussed.


title:
Recent star formation in nearby 3CR radio-galaxies from UV HST
  observations

abstract:
  We analyzed HST images of 31 nearby (z <~ 0.1) 3CR radio-galaxies. We
compared their UV and optical images to detect evidence of recent star
formation. Six objects were excluded because they are highly nucleated or had
very low UV count rates. After subtracting the emission from their nuclei
and/or jets, 12 of the remaining 25 objects, presenting an UV/optical colors
NUV - r < 5.4, are potential star-forming candidates. Considering the
contamination from other AGN-related processes (UV emission lines, nebular
continuum, and scattered nuclear light), there are 6 remaining star-forming
"blue" galaxies.
  We then divide the radio galaxies, on the basis of the radio morphology,
radio power, and diagnostic optical line ratios, into low and high excitation
galaxies, LEG and HEG. While there is no correlation between the FR type (or
radio power) and color, the FR type is clearly related to the spectroscopic
type. In fact, all HEG (with one possible exception) show morphological
evidence of recent star formation in UV compact knots, extended over 5-20 kpc.
Conversely, there is only 1 "blue" LEG out of 19, including in this class also
FR I galaxies.
  The picture that emerges, considering color, UV, optical, and dust
morphology, is that only in HEG recent star formation is associated with these
relatively powerful AGN, which are most likely triggered by a recent, major,
wet merger. Conversely, in LEG galaxies the fraction of actively star-forming
objects is not enhanced with respect to quiescent galaxies. The AGN activity in
these sources can be probably self-sustained by their hot interstellar medium.


title:
High-gain DC-mode operated Gaseous Photomultipliers for the visible
  spectral range

abstract:
  We shortly describe recent progress in photon detectors combining bi-alkali
photocathodes and cascaded patterned gas-avalanche electron multipliers. It
permitted the development and the first feasibility demonstration of high-gain
gaseous photomultipliers sensitive in the visible spectral range, operated in
DC mode with single-photon sensitivity.


title: Superconductivity at 2.2K in La3Ni4P4O2

abstract:
  We report the observation of superconductivity in La3Ni4P4O2 at 2.2 K. The
layer stacking in this compound results in an asymmetric distribution of charge
reservoir layers around the Ni2P2 planes. The estimated Wilson ratio, Rw ~ 5,
indicates the presence of a strongly enhanced normal state susceptibility, but
many of the basic superconducting characteristics are conventional. The
estimated electronic contribution to the specific heat, gamma ~ 6.2 mJ
mol-Ni^-1K^-2, is about 2/3 of that found in layered nickel borocarbide
superconductors.


title: Quantum algorithm design using dynamic learning

abstract:
  We present a dynamic learning paradigm for "programming" a general quantum
computer. A learning algorithm is used to find the control parameters for a
coupled qubit system, such that the system at an initial time evolves to a
state in which a given measurement corresponds to the desired operation. This
can be thought of as a quantum neural network. We first apply the method to a
system of two coupled superconducting quantum interference devices (SQUIDs),
and demonstrate learning of both the classical gates XOR and XNOR. Training of
the phase produces a gate congruent to the CNOT modulo a phase shift. Striking
out for somewhat more interesting territory, we attempt learning of an
entanglement witness for a two qubit system. Simulation shows a reasonably
successful mapping of the entanglement at the initial time onto the correlation
function at the final time for both pure and mixed states. For pure states this
mapping requires knowledge of the phase relation between the two parts;
however, given that knowledge, this method can be used to measure the
entanglement of an otherwise unknown state. The method is easily extended to
multiple qubits or to quNits.


title: Global solutions in gravity. Euclidean signature

abstract:
  We consider a wide class of two-dimensional metrics having one Killing
vector. The method is proposed for the construction of maximally extended
surfaces with the given Riemannian metric which is the analog of the conformal
block method for two-dimensional Lorentzian signature metrics. The
Schwarzschild solution is considered as an example.


title: Liouville Quantum Gravity and KPZ

abstract:
  Consider a bounded planar domain D, an instance h of the Gaussian free field
on D (with Dirichlet energy normalized by 1/(2\pi)), and a constant 0 < gamma <
2. The Liouville quantum gravity measure on D is the weak limit as epsilon
tends to 0 of the measures \epsilon^{\gamma^2/2} e^{\gamma h_\epsilon(z)}dz,
where dz is Lebesgue measure on D and h_\epsilon(z) denotes the mean value of h
on the circle of radius epsilon centered at z. Given a random (or
deterministic) subset X of D one can define the scaling dimension of X using
either Lebesgue measure or this random measure. We derive a general quadratic
relation between these two dimensions, which we view as a probabilistic
formulation of the KPZ relation from conformal field theory. We also present a
boundary analog of KPZ (for subsets of the boundary of D). We discuss the
connection between discrete and continuum quantum gravity and provide a
framework for understanding Euclidean scaling exponents via quantum gravity.


title:
Measuring Dislocation Density in Aluminum with Resonant Ultrasound
  Spectroscopy

abstract:
  Dislocations in a material will, when present in enough numbers, change the
speed of propagation of elastic waves. Consequently, two material samples,
differing only in dislocation density, will have different elastic constants, a
quantity that can be measured using Resonant Ultrasound Spectroscopy.
Measurements of this effect on aluminum samples are reported. They compare well
with the predictions of the theory.


title: Persistence of zero modes in a gauged Dirac model for bilayer graphene

abstract:
  A recently constructed model for low lying excitations in bilayer graphene
exhibits mid-gap, zero energy modes in its Dirac-like spectrum, when a scalar
order parameter takes a vortex profile. We show that these modes persist when
the dynamics is extended by a gauge field interaction, which also renders
finite the vortex energy. The effect of the gauge field on the zero energy wave
function is to shift the phase of the (damped) oscillatory component of the
wave function in the absence of the gauge field.


title:
Beyond the frame rate: Measuring high-frequency fluctuations with light
  intensity modulation

abstract:
  Power spectral density measurements of any sampled signal are typically
restricted by both acquisition rate and frequency response limitations of
instruments, which can be particularly prohibitive for video-based
measurements. We have developed a new method called Intensity Modulation
Spectral Analysis (IMSA) that circumvents these limitations, dramatically
extending the effective detection bandwidth. We demonstrate this by
video-tracking an optically-trapped microsphere while oscillating an LED
illumination source. This approach allows us to quantify fluctuations of the
microsphere at frequencies over 10 times higher than the Nyquist frequency,
mimicking a significantly higher frame rate.


title:
On the structure of the wave operators in one dimensional potential
  scattering

abstract:
  In the framework of one dimensional potential scattering we prove that,
modulo a compact term, the wave operators can be written in terms of a
universal operator and of the scattering operator. The universal operator is
related to the one dimensional Hilbert transform and can be expressed as a
function of the generator of dilations. As a consequence, we show how
Levinson's theorem can be rewritten as an index theorem, and obtain the
asymptotic behaviour of the wave operators at high and low energy and at large
and small scale.


title:
Obscured clusters. II. GLIMPSE-C02 - A new metal rich globular cluster
  in the Milky Way

abstract:
  The estimated total number of Milky Way globulars is 160+-20. The question of
whether there are any more undiscovered globular clusters in the Milky Way is
particularly relevant with advances in near and mid-IR instrumentation. This
investigation is a part of a long-term project to search the inner Milky Way
for hidden star clusters and to study them in detail. GLIMPSE-C02 (G02) is one
of these objects, situated near the Galactic plane (l=14.129deg, b=-0.644deg).
Our analysis is based on SOFI/NTT JHKs imaging and low resolution (R~1400)
spectroscopy of three bright cluster red giants in the K atmospheric window. We
derived the metal abundance by analysis of these spectra and from the slope of
the RGB. The cluster is deeply embedded in dust and undergoes a mean reddening
of Av~24.8+-3 mag. The distance to the object is D=4.6+-0.7kpc. The metal
abundance of G02 is [Fe/H](H96)=-0.33+-0.14 and [Fe/H](CG)=-0.16+-0.12 using
different scales. The best fit to the radial surface brightness profile with a
single-mass King's model yields a core radius rc=0.70 arcmin (0.9pc), tidal
radius rt=15 arcmin (20pc), and central oncentration c=1.33. We demonstrate
that G02 is new Milky Way globular cluster, among the most metal rich globular
clusters in the Galaxy. The object is physically located at the inner edge of
the thin disk and the transition region with the bulge, and also falls in the
zone of the "missing" globulars toward the central region of the Milky Way.


title:
Structural, Vibrational and Thermodynamic Properties of AgnCu34-n
  Nanoparticles

abstract:
  We report results of a systematic study of structural, vibrational and
thermodynamical properties of 34-atom bimetallic nanoparticles from the
AgnCu34-n family using model interaction potentials as derived from the
embedded atom method and in the harmonic approximation of lattice dynamics.
Systematic trends in the bond length and dynamical properties can be explained
largely on arguments based on local coordination and elemental environment.
Thus increase in the number of silver atoms in a given neighborhood introduces
a monotonic increase in bond length while increase of the copper content does
the reverse. Moreover, based on bond lengths of the lowest coordinated (6 and
8) copper atoms with their nearest neighbors (Cu atoms), we find that the
nanoparticles divide into two groups with average bond length either close to
(~ 2.58 A) or smaller (~ 2.48 A) than that in bulk copper, accompanied by
characteristic features in their vibrational density of states. For the entire
set of nanoparticles, vibrational modes are found above the bulk bands of
copper/silver. Furthermore, a blue shift in the high frequency end with
increasing number of copper atoms in the nanoparticles is traced to a shrinkage
of bond lengths from bulk values. The vibrational densities of states at the
low frequency end of the spectrum scale linearly with frequency as for single
element nanoparticles, however, the effect is more pronounced for these
nanoalloys. The Debye temperature was found to be about one third of that of
the bulk for pure copper and silver nanoparticles with a non-linear increase
with increasing number of copper atoms in the nanoalloys.


title:
Sivers Asymmetries for Inclusive Pion and Kaon Production in
  Deep-Inelastic Scattering

abstract:
  We calculate the Sivers distribution functions induced by the final-state
interaction due to one-gluon exchange in diquark models of nucleon structure,
treating the cases of scalar and axial-vector diquarks with both dipole and
Gaussian form factors. We use these distribution functions to calculate the
Sivers single-spin asymmetries for inclusive pion and kaon production in
deep-inelastic scattering. We compare our calculations with the results of
HERMES and COMPASS, finding good agreement for pi+ production at HERMES, and
qualitative agreement for pi0 and K+ production. Our predictions for pion and
kaon production at COMPASS could be probed with increased statistics. The
successful comparison of our calculations with the HERMES data constitutes
prima facie evidence that the quarks in the nucleon have some orbital angular
momentum in the infinite-momentum frame.


title: Spacings and pair correlations for finite Bernoulli convolutions

abstract:
  We consider finite Bernoulli convolutions with a parameter $1/2 < r < 1$
supported on a discrete point set, generically of size $2^N$. These sequences
are uniformly distributed with respect to the infinite Bernoulli convolution
measure $\nu_r$, as $N$ tends to infinity. Numerical evidence suggests that for
a generic $r$, the distribution of spacings between appropriately rescaled
points is Poissonian. We obtain some partial results in this direction; for
instance, we show that, on average, the pair correlations do not exhibit
attraction or repulsion in the limit. On the other hand, for certain algebraic
$r$ the behavior is totally different.


title: Semi-Flatland

abstract:
  We study perturbative compactifications of Type II string theory that rely on
a fibration structure of the extra dimensions a la SYZ. Non-geometric spaces
are obtained by using T-dualities as monodromies. These vacua generically
preserve N=1 supersymmetry in four dimensions, and are U-dual to M-theory on G2
manifolds. Several examples are discussed, some of which admit an asymmetric
orbifold description. The massless spectrum is matched to that of the dual
M-theory compactification on a Joyce manifold when a comparison is possible. We
explore the possibility of twisted reductions where left-moving spacetime
fermion number Wilson lines are turned on in the fiber. We also give an
explanation from this semiflat viewpoint for the Hanany-Witten brane-creation
effect and for the equivalence of the Type IIA orientifold on T5/Z2 and Type
IIB on S1 x K3.


title: Superhorizon Perturbations and the Cosmic Microwave Background

abstract:
  Superhorizon perturbations induce large-scale temperature anisotropies in the
cosmic microwave background (CMB) via the Grishchuk-Zel'dovich effect. We
analyze the CMB temperature anisotropies generated by a single-mode adiabatic
superhorizon perturbation. We show that an adiabatic superhorizon perturbation
in a LCDM universe does not generate a CMB temperature dipole, and we derive
constraints to the amplitude and wavelength of a superhorizon potential
perturbation from measurements of the CMB quadrupole and octupole. We also
consider constraints to a superhorizon fluctuation in the curvaton field, which
was recently proposed as a source of the hemispherical power asymmetry in the
CMB.


title: Gauge Mediation in F-Theory GUT Models

abstract:
  We study a simple framework for gauge-mediated supersymmetry-breaking in
local GUT models based on F-theory 7-branes and demonstrate that a mechanism
for solving both the \mu and \mu/B_{\mu} problems emerges in a natural way. In
particular, a straightforward coupling of the messengers to the Higgs sector
leads to a geometry which not only provides us with an approximate U(1)_{PQ}
symmetry that forbids the generation of \mu at the GUT scale, it also forces
the SUSY-breaking spurion field to carry a nontrivial PQ charge. This connects
the breaking of SUSY to the generation of \mu so that the same scale enters
both. Moreover, the messenger sector naturally realizes the D3-instanton
triggered Polonyi model of arXiv:0808.1286 so this scale is exponentially
suppressed relative to M_{GUT}. The effective action at low scales is in fact
precisely of the form of the "sweet spot supersymmetry" scenario studied by Ibe
and Kitano in arXiv:0705.3686.


title:
Circles-in-the-sky searches and observable cosmic topology in the
  inflationary limit

abstract:
  While the topology of the Universe is at present not specified by any known
fundamental theory, it may in principle be determined through observations. In
particular, a non-trivial topology will generate pairs of matching circles of
temperature fluctuations in maps of the cosmic microwave background, the
so-called circles-in-the-sky. A general search for such pairs of circles would
be extremely costly and would therefore need to be confined to restricted
parameter ranges. To draw quantitative conclusions from the negative results of
such partial searches for the existence of circles we need a concrete
theoretical framework. Here we provide such a framework by obtaining
constraints on the angular parameters of these circles as a function of
cosmological density parameters and the observer's position. As an example of
the application of our results, we consider the recent search restricted to
pairs of nearly back-to-back circles with negative results. We show that
assuming the Universe to be very nearly flat, with its total matter-energy
density satisfying the bounds $ 0 <|\Omega_0 - 1| \lesssim 10^{-5}$, compatible
with the predictions of typical inflationary models, this search, if confirmed,
could in principle be sufficient to exclude a detectable non-trivial cosmic
topology for most observers. We further relate explicitly the fraction of
observers for which this result holds to the cosmological density parameters.


title:
Systematic Analysis of Frustration Effects in Anisotropic Checkerboard
  Lattice Hubbard Model

abstract:
  We study the ground state properties of the geometrically frustrated Hubbard
model on the anisotropic checkerboard lattice with nearest-neighbor hopping $t$
and next nearest-neighbor hopping $t'$. By using the path-integral
renormalization group method, we study the phase diagram in the parameter space
of the Hubbard interaction $U$ and the frustration-control parameter $t'/t$.
Close examinations of the effective hopping, the double occupancy, the momentum
distribution and the spin/charge correlation functions allow us to determine
the phase diagram at zero temperature, where the plaquette-singlet insulator
emerges besides the antiferromagnetic insulator and the paramagnetic metal.
Spin-liquid insulating states without any kind of symmetry breaking cannot be
found in our frustrated model.


title: The Evolution of Late-Time Optical Emission From SN 1979C

abstract:
  Optical spectra of the bright Type II-L supernova SN 1979C obtained in April
2008 with the 6.5 m MMT telescope are compared with archival late-time spectra
to follow the evolution of its optical emission over the age range of 11 to 29
years. We estimate an Halpha flux decrease of around 35% from 1993 to 2008 but
noticeable increases in the strength of blueshifted emission of forbidden
oxygen lines. While the maximum expansion of the broad ~6700 km/s Halpha
emission appears largely unchanged from 1993, we find a significant narrowing
of the double-peaked emission profiles in the [O I] 6300, 6364 and [O II] 7319,
7330 lines. A comparison of late-time optical spectra of a few other Type II
supernovae which, like SN 1979C, exhibit bright late-time X-ray, optical, and
radio emissions, suggests that blueshifted double-peaked oxygen emission
profiles may be a common phenomenon. Finally, detection of a faint, broad
emission bump centered around 5800 Angstroms suggests the presence of WC type
Wolf-Rayet stars in the supernova's host star cluster.


title: Discovery of a Wide Substellar Companion to a Nearby Low-Mass Star

abstract:
  We report the discovery of a wide (135+/-25 AU), unusually blue L5 companion
2MASS J17114559+4028578 to the nearby M4.5 dwarf G 203-50 as a result of a
targeted search for common proper motion pairs in the Sloan Digital Sky Survey
and the Two Micron All Sky Survey. Adaptive Optics imaging with Subaru
indicates that neither component is a nearly equal mass binary with separation
> 0.18", and places limits on the existence of additional faint companions. An
examination of TiO and CaH features in the primary's spectrum is consistent
with solar metallicity and provides no evidence that G 203-50 is metal poor. We
estimate an age for the primary of 1-5 Gyr based on activity. Assuming
coevality of the companion, its age, gravity and metallicity can be constrained
from properties of the primary, making it a suitable benchmark object for the
calibration of evolutionary models and for determining the atmospheric
properties of peculiar blue L dwarfs. The low total mass (M_tot=0.21+/-0.03
M_sun), intermediate mass ratio (q=0.45+/-0.14), and wide separation of this
system demonstrate that the star formation process is capable of forming wide,
weakly bound binary systems with low mass and BD components. Based on the
sensitivity of our search we find that no more than 2.2% of early-to-mid M
dwarfs (9.0 < M_V < 13.0) have wide substellar companions with m > 0.06 M_sun.


title: The equilibrium intrinsic crystal-liquid interface of colloids

abstract:
  We use confocal microscopy to study an equilibrated crystal-liquid interface
in a colloidal suspension. Capillary waves roughen the surface, but locally the
intrinsic interface is sharply defined. We use local measurements of the
structure and dynamics to characterize the intrinsic interface, and different
measurements find slightly different widths of this interface. In terms of the
particle diameter $d$, this width is either $1.5d$ (based on structural
information) or $2.4d$ (based on dynamics), both not much larger than the
particle size. This work is the first direct experimental visualization of an
equilibrated crystal-liquid interface.


title:
Electrostatic deposition of graphene in a gaseous environment: A
  deterministic route to synthesize rolled graphenes?

abstract:
  The synthesis of single-wall carbon nanotubes (SWCNTs) of desired diameters
and chiralities is critical to the design of nanoscale electronic devices with
desired properties.1-6 The existing methods are based on self-assembly, 7-16
therefore lacking the control over their diameters and chiralities. The present
work reports a direct route to roll graphene. Specifically, we found that the
electrostatic deposition of graphene yielded: (i) flat graphene layers under
high vacuum (10-7 Torr), (ii) completely scrolled graphene under hydrogen
atmosphere, (iii) partially scrolled graphene under nitrogen atmosphere, and
(iv) no scrolling for helium atmospheres. Our study shows that the application
of the electrostatic field facilitates the rolling of graphene sheets exposed
to appropriate gases and allows the rolling of any size graphene. The technique
proposed here, in conjunction with a technique that produces graphene
nanoribbons (GNRs) of uniform widths, will have significant impact on the
development of carbon nanotube based devices. Furthermore, the present
technique may be applied to obtain tubes/scrolls of other layered materials.


title:
On the Phase Diagram of Spin-Polarized Attractive Hubbard Model: Weak
  Coupling Limit

abstract:
  The superfluid properties of the attractive Hubbard model in a Zeeman
magnetic field, and in the weak coupling regime have been investigated. The
temperature and magnetic field dependencies of the order parameter have been
analyzed. Furthermore, the temperature vs. magnetic field and temperature vs.
spin polarization phase diagrams for the 2D and 3D lattices have been obtained.
For some parameters a reentrant transition has been found.


title:
Transverse Commensurability Effect for Vortices in Periodic Pinning
  Arrays

abstract:
  Using computer simulations, we demonstrate a new type of commensurability
that occurs for vortices moving longitudinally through periodic pinning arrays
in the presence of an additional transverse driving force. As a function of
vortex density, there is a series of broad maxima in the transverse critical
depinning force that do not fall at the matching fields where the number of
vortices equals an integer multiple of the number of pinning sites. The
commensurability effects are associated with dynamical states in which evenly
spaced structures consisting of one or more moving rows of vortices form
between rows of pinning sites. Remarkably, the critical transverse depinning
force can be more than an order of magnitude larger than the longitudinal
depinning force.


title: Varying-Alpha Cosmologies with Potentials

abstract:
  We generalize the Bekenstein-Sandvik-Barrow-Magueijo (BSBM) model for the
variation of the fine structure 'constant', $\alpha ,$ to include an
exponential or inverse power-law self-potential for the scalar field $% \phi $
which drives the time variation of $\alpha $, and consider the dynamics of
$\phi$ in such models. We find solutions for the evolution of $\phi $ or
$\alpha $ in matter-, radiation- and dark-energy-dominated cosmic eras. In
general, the evolution of $\phi $ is well determined solely by either the
self-potential or the coupling to matter, depending on the model parameters.
The results are general and applicable to other models where the evolution of a
scalar field is governed by a matter coupling and a self-potential. We find
that the existing astronomical data stringently constrains the possible
evolution of $\alpha $ between redshifts $z\simeq 1-3.5$ and the present, and
this leads to very strong limit on the allowed deviation of the potential from
that of a pure cosmological constant.


title: On Conway and Kochen's "Thou shalt not clone one bit!"

abstract:
  A physicists' explanation of why thou shalt not clone one bit gives a
stronger version of Conway and Kochen's theorem.


title: On the absence of a measurement problem in quantum computer science

abstract:
  I comment on GianCarlo Ghirardi's criticism of my claim that quantum
computation has no measurement problem.


title: SDiff Gauge Theory and the M2 Condensate

abstract:
  We develop a general formalism for the construction, in $D$-dimensional
Minkowski space, of gauge theories for which the gauge group is the
infinite-dimensional group SDiff$_n$ of volume-preserving diffeomorphisms of
some closed $n$-dimensional manifold. We then focus on the D=3 SDiff$_3$
superconformal gauge theory describing a condensate of M2-branes; in
particular, we derive its ${\cal N}=8$ superfield equations from a pure-spinor
superspace action, and we describe its relationship to the D=3 SDiff$_2$
super-Yang-Mills theory describing a condensate of D2-branes.


title: Link invariants from finite Coxeter racks

abstract:
  We study Coxeter racks over $\mathbb{Z}_n$ and the knot and link invariants
they define. We exploit the module structure of these racks to enhance the rack
counting invariants and give examples showing that these enhanced invariants
are stronger than the unenhanced rack counting invariants.


title: Homological Dimensions in Cotorsion Pairs

abstract:
  Two classes $\mathcal A$ and $\mathcal B$ of modules over a ring $R$ are said
to form a cotorsion pair $(\mathcal A, \mathcal B)$ if $\mathcal A={\rm Ker
Ext}^1_R(-,\mathcal B)$ and $\mathcal B={\rm Ker Ext}^1_R(\mathcal A,-)$. We
investigate relative homological dimensions in cotorsion pairs. This can be
applied to study the big and the little finitistic dimension of $R$. We show
that $\Findim R<\infty$ if and only if the following dimensions are finite for
some cotorsion pair $(\mathcal A, \mathcal B)$ in $\mathrm{Mod} R$: the
relative projective dimension of $\A$ with respect to itself, and the $\mathcal
A$-resolution dimension of the category $\mathcal P$ of all $R$-modules of
finite projective dimension. Moreover, we obtain an analogous result for
$\findim R$, and we characterize when $\Findim R=\findim R.$


title: Glassy states in fermionic systems with strong disorder and interactions

abstract:
  We study the competition between interactions and disorder in two dimensions.
Whereas a noninteracting system is always Anderson localized by disorder in two
dimensions, a pure system can develop a Mott gap for sufficiently strong
interactions. Within a simple model, with short-ranged repulsive interactions,
we show that, even in the limit of strong interaction, the Mott gap is
completely washed out by disorder for an infinite system for dimensions $D\le
2$. The probability of a nonzero gap falls onto a universal curve, leading to a
glassy state for which we provide a scaling function for the frequency
dependent susceptibility.


title: The structure of electronic polarization and its strain dependence

abstract:
  The $\phi(\kpp)\sim \kpp$ relation is called polarization structure. By
density functional calculations, we study the polarization structure in
ferroelectric perovskite PbTiO$_3$, revealing (1) the $\kpp$ point that
contributes most to the electronic polarization, (2) the magnitude of
bandwidth, and (3) subtle curvature of polarization dispersion. We also
investigate how polarization structure in PbTiO$_3$ is modified by compressive
inplane strains. The bandwidth of polarization dispersion in PbTiO$_3$ is shown
to exhibit an unusual decline, though the total polarization is enhanced. As
another outcome of this study, we formulate an analytical scheme for the
purpose of identifying what determine the polarization structure at arbitrary
$\kpp$ points by means of Wannier functions. We find that $\phi(\kpp)$ is
determined by two competing factors: one is the overlaps between neighboring
Wannier functions within the plane {\it perpendicular} to the polarization
direction, and the other is the localization length {\it parallel} to the
polarization direction. Inplane strain increases the former while decreases the
latter, causing interesting non-monotonous effects on polarization structure.
Finally, polarization dispersion in another paradigm ferroelectric BaTiO$_3$ is
discussed and compared with that of PbTiO$_3$.


title: A Generalized Publication Bias Model

abstract:
  Scargle (2000) has discussed Rosenthal and Rubin's (1978) "fail-safe number"
(FSN) method for estimating the number of unpublished studies in meta-analysis.
He concluded that this FSN cannot possibly be correct because a central
assumption the authors used conflicts with the very definition of publication
bias. While this point has been made by others before (Elsahoff, 1978;
Darlington, 1980; Thomas, 1985, Iyengar & Greenhouse, 1988), Scargle showed, by
way of a simple 2-parameter model, how far off Rosenthal & Rubin' s estimate
can be in practice. However, his results relied on the assumption that the
decision variable is normally distributed with zero mean. In this case the
ratio of unpublished to published papers is large only in a tiny region of the
parameter plane.
  Building on these results, we now show that (1) Replacing densities with
probability masses greatly simplifies Scargle's derivations and permits an
explicit statement of the relation between the probability alpha of Type I
errors and the step-size beta; (2) This result does not require any
distribution assumptions; (3) The distinction between 1-sided and 2-sided
rejection regions becomes immaterial; (4) This distribution-free approach leads
to an immediate generalization to partitions involving more than two intervals,
and thus covers more general selection functions.


title: On the average growth exponent for beta-expansions

abstract:
  Let $\be\in(1,2)$. Each $x\in I_\be:=[0,\frac{1}{\be-1}]$ can be represented
in the form \[ x=\sum_{k=1}^\infty a_k\be^{-k}, \] where $a_k\in\{0,1\}$ for
all $k$ (a $\be$-expansion of $x$). It was shown in \cite{S} that a.e. $x\in
I_\be$ has a continuum of distinct $\be$-expansions. In this paper we show that
for a generic $x$, this continuum has one and the same growth rate, i.e., the
general $\be$-expansions exhibit an ergodic behaviour.
  When $\be<\frac{1+\sqrt5}2$, we show that the set of $\be$-expansions grows
exponentially for every $x\in(0,\frac{1}{\be-1})$. Special attention is paid to
the case $\be=\frac{1+\sqrt5}2$, for which we explicitly compute the average
growth exponent and apply this result to evaluating the local dimension of the
corresponding Bernoulli convolution at a Lebesgue-generic $x$.


title: The Network Species Model

abstract:
  We propose a theoretical model for species that is focused on intrinsic
organization and processes. Specifically, we regard species to be networks of
organisms integrated by reproductive mechanisms (e.g., conjugation, meiosis,
syngamy) regardless of degree or type of divergence, longevity, size, fate, or
other criteria. Ramifications of viewing units of diversity in terms of
inherent organization include the following: (1) Species, subspecies,
population, deme, Evolutionary Significant Unit (ESU), and related terms cannot
be distinguished on the basis of inherent organization and, consequently, do
not reflect a hierarchy of organization. In other words, only one model is
required to explain systems composed of organisms. (2) Temporarily isolated
networks of organisms possess the same intrinsic organization and, therefore,
the same ontological status as permanently isolated systems. (3) Units of
diversity are recognized regardless of kind or degree of divergence. (4) Fate
is not an intrinsic property of systems and is an inappropriate consideration
in species models. (5) Networks are recognized at the moment they become
isolated; therefore, resultant classifications reflect the causal events that
generate diversity (e.g., vicariance) rather than post-vicariance events such
as character evolution and, consequently, have greater historical relevance
(e.g., biogeography). (6) Because the proposed model is based on organization,
it is similar to models in other disciplines (e.g., astronomy, chemistry, and
physics) and should lead to greater unification of thought within biology and
among scientific disciplines. (7) Lineage concepts are problematic because they
do not describe a unique level of biological organization and because
ancestor-descendant relationships are not unique to living systems.


title:
A scalable, high-speed measurement-based quantum computer using trapped
  ions

abstract:
  We describe a scalable, high-speed, and robust architecture for
measurement-based quantum-computing with trapped ions. Measurement-based
architectures offer a way to speed-up operation of a quantum computer
significantly by parallelizing the slow entangling operations and transferring
the speed requirement to fast measurement of qubits. We show that a 3D cluster
state suitable for fault-tolerant measurement-based quantum computing can be
implemented on a 2D array of ion traps. We propose the projective measurement
of ions via multi-photon photoionization for nanosecond operation and discuss
the viability of such a scheme for Ca ions.


title: The sharp energy-capacity inequality

abstract:
  Using the Oh-Schwarz spectral invariants and some arguments of Frauenfelder,
Ginzburg, and Schlenk, we show that the \pi_1-sensitive Hofer-Zehnder capacity
of any subset of a closed symplectic manifold is less than or equal to its
displacement energy. This estimate is sharp, and implies some new extensions of
the Non-Squeezing Theorem.


title:
High-energy Particle Acceleration and Production of Ultra-high-energy
  Cosmic Rays in the Giant Lobes of Centaurus A

abstract:
  The nearby radio galaxy Centaurus A is poorly studied at high frequencies
with conventional radio telescopes because of its very large angular size, but
is one of a very few extragalactic objects to be detected and resolved by the
Wilkinson Microwave Anisotropy Probe (WMAP). We have used the five-year WMAP
data for Cen A to constrain the high-frequency radio spectra of the 10-degree
giant lobes and to search for spectral changes as a function of position along
the lobes. We show that the high-frequency radio spectra of the northern and
southern giant lobes are significantly different: the spectrum of the southern
lobe steepens monotonically (and is steeper further from the active nucleus)
whereas the spectrum of the northern lobe remains consistent with a power law.
The inferred differences in the northern and southern giant lobes may be the
result of real differences in their high-energy particle acceleration
histories, perhaps due to the influence of the northern middle lobe, an
intermediate-scale feature which has no detectable southern counterpart. In
light of these results, we discuss the prospects for Fermi Gamma-ray Space
Telescope detections of inverse-Compton emission from the giant lobes and the
lobes' possible role in the production of the ultra-high energy cosmic rays
(UHECR) detected by the Pierre Auger Observatory. We show that the possibility
of a Fermi detection depends sensitively on the physical conditions in the
giant lobes, with the northern lobe more likely to be detected, and that any
emission observed by Fermi is likely to be dominated by photons at the soft end
of the Fermi energy band. On the other hand we argue that the estimated
conditions in the giant lobes imply that UHECRs can be accelerated there, with
a potentially detectable gamma-ray signature at TeV energies.


title:
Extremely high precision VLBI astrometry of PSR J0437-4715 and
  implications for theories of gravity

abstract:
  Using the recently upgraded Long Baseline Array, we have measured the
trigonometric parallax of PSR J0437-4715 to better than 1% precision, the most
precise pulsar distance determination made to date. Comparing this VLBI
distance measurement to the kinematic distance obtained from pulsar timing,
which is calculated from the pulsar's proper motion and apparent rate of change
of orbital period, gives a precise limit on the unmodeled relative acceleration
between the Solar System and PSR J0437-4715, which can be used in a variety of
applications. Firstly, it shows that Newton's gravitational constant G is
stable with time (\dot{G}/G = (-5 +- 26) x 10^{-13} yr^{-1}, 95% confidence).
Secondly, if a stochastic gravitational wave background existed at the
currently quoted limit, this null result would fail ~50% of the time. Thirdly,
it excludes Jupiter-mass planets within 226 AU of the Sun in 50% of the sky
(95% confidence). Finally, the ~1% agreement of the parallax and orbital period
derivative distances provides a fundamental confirmation of the parallax
distance method upon which all astronomical distances are based.


title:
Decoding the Mechanism for the Origin of Dark Matter in the Early
  Universe Using LHC Data

abstract:
  It is shown that LHC data can allow one to decode the mechanism by which dark
matter is generated in the early universe in supersymmetric theories. We focus
on two of the major mechanisms for such generation of dark matter which are
known to be the Stau Coannihilation (Stau-Co) where the neutralino is typically
Bino like and annihilation on the Hyperbolic Branch (HB) where the neutralino
has a significant Higgsino component. An investigation of how one may
discriminate between the Stau-Co region and the HB region using LHC data is
given for the mSUGRA model. The analysis utilizes several signatures including
multi leptons, hadronic jets, b-tagging, and missing transverse momentum. A
study of the SUSY signatures reveals several correlated smoking gun signals
allowing a clear discrimination between the Stau-Co and the HB regions where
dark matter in the early universe can originate.