title:
Carter-like constants of the motion in Newtonian gravity and
  electrodynamics

abstract:
  For a test body orbiting an axisymmetric body in Newtonian gravitational
theory with multipole moments Q_L, (and for a charge in a non-relativistic
orbit about a charge distribution with the same multipole moments) we show that
there exists, in addition to the energy and angular momentum component along
the symmetry axis, a conserved quantity analogous to the Carter constant of
Kerr spacetimes in general relativity, if the odd-L moments vanish, and the
even-L moments satisfy Q_2L = m (Q_2/m)^L. Strangely, this is precisely the
relation among mass moments enforced by the no-hair theorems of rotating black
holes. By contrast, if Newtonian gravity is supplemented by a multipolar
gravitomagnetic field, whose leading term represents frame-dragging (or if the
electrostatic field is supplemented by a multipolar magnetic field), we are
unable to find an analogous Carter-like constant. This further highlights the
very special nature of the Kerr geometry of general relativity.


title: Isomorphisms of Additive Cellular Automata on Finite Groups

abstract:
  We study sources of isomorphisms of additive cellular automata on finite
groups (called index-group). It is shown that many isomorphisms (called
regular) of automata are reducible to the isomorphisms of underlying algebraic
structures (such as the index-group, monoid of automata rules, and its subgroup
of reversible elements). However for some groups there exist not regular
automata isomorphisms. A complete description of linear automorphisms of the
monoid is obtained. These automorphisms cover the most part of all automata
isomorphisms for small groups and are represented by reversible matrices M such
that for any index-group circulant C the matrix M^{-1}CM is an index-group
circulant.


title: On Families of (Phi,Gamma)-modules

abstract:
  Berger and Colmez introduced a theory of families of overconvergent \'etale
(Phi,Gamma)-modules associated to families of p-adic Galois representations
over p-adic Banach algebras. However, in contrast with the classical theory of
(Phi,Gamma)-modules, the functor they obtain is not an equivalence of
categories. In this paper, we prove that when the base is an affinoid space,
every family of (overconvergent) \'etale (Phi,Gamma)-modules can locally be
converted into a family of p-adic representations in a unique manner, providing
the "local" equivalence. There is a global mod p obstruction related to the
moduli of residual representations.


title:
Spin and orbital Hall effects for diffracting optical beams in
  gradient-index media

abstract:
  We examine the evolution of paraxial beams carrying intrinsic spin and
orbital angular momenta (AM) in gradient-index media. A parabolic-type equation
is derived which describes the beam diffraction in curvilinear coordinates
accompanying the central ray. The center of gravity of the beam experiences
transverse AM-dependent deflections -- the spin and orbital Hall effects. The
spin Hall effect generates a transverse translation of the beam as a whole, in
precise agreement with recent geometrical optics predictions. At the same time,
the orbital Hall effect is significantly affected by the diffraction in the
inhomogeneous medium and is accompanied by changes in the intrinsic orbital AM
and deformations of the beam.


title: Degeneracy, the virial theorem, and stellar collapse

abstract:
  Formulae for the energies of degenerate non-relativistic and
ultra-relativistic Fermi gases play multiple roles in simple arguments related
to the collapse of a stellar core to a neutron star. These formulae, deployed
in conjunction with the virial theorem and a few other basic physical
principles, provide surprisingly good estimates of the temperature, mass, and
radius (and therefore also density and entropy) of the core at the onset of
collapse; the final radius and composition of the cold compact remnant; and the
total energy lost to neutrino emission during collapse.


title: Vision as Adaptive Epistemology

abstract:
  In the last years the debate on complexity has been developing and developing
in transdisciplinary way to meet the need of explanation for highly organized
collective behaviors and sophisticated hierarchical arrangements in physical,
biological, cognitive and social systems. Unfortunately, no clear definition
has been reached, so complexity appears like an anti-reductionist paradigm in
search of a theory. In our short survey we aim to suggest a clarification in
relation to the notions of computational and intrinsic emergence, and to show
how the latter is deeply connected to the new Logical Openness Theory, an
original extension of Godel theorems to the model theory. The epistemological
scenario we are going to make use of is that of the theory of vision, a
particularly instructive one. Vision is an element of our primordial
relationship with the world;consequently it comes as no surprise that carefully
taking into consideration the processes of visual perception can lead us
straight to some significant questions useful to delineate a natural history of
knowledge. The common Greek etymological root of theory and vision sounds like
a metaphor pointing out the analogy between the modalities of vision and those
we use to see and build the world because them both can say us something about
the central role of the observer and the semantic complexity of cognitive
strategies.


title:
Dissociation of the benzene molecule by UV and soft X-rays in
  circumstellar environment

abstract:
  Benzene molecules, present in the proto-planetary nebula CRL 618, are ionized
and dissociated by UV and X-ray photons originated from the hot central star
and by its fast wind. Ionic species and free radicals produced by these
processes can lead to the formation of new organic molecules. The aim of this
work is to study the photoionization and photodissociation processes of the
benzene molecule, using synchrotron radiation and time of flight mass
spectrometry. Mass spectra were recorded at different energies corresponding to
the vacuum ultraviolet (21.21 eV) and soft X-ray (282-310 eV) spectral regions.
The production of ions from the benzene dissociative photoionization is here
quantified, indicating that C6H6 is more efficiently fragmented by soft X-ray
than UV radiation, where 50% of the ionized benzene molecules survive to UV
dissociation while only about 4% resist to X-rays. Partial ion yields of H+ and
small hydrocarbons such as C2H2+, C3H3+ and C4H2+ are determined as a function
of photon energy. Absolute photoionization and dissociative photoionization
cross sections have also been determined. From these values, half-life of
benzene molecule due to UV and X-ray photon fluxes in CRL 618 were obtained.


title:
Bounds for the annealed return probability on large finite percolation
  clusters

abstract:
  Bounds for the expected return probability of the delayed random walk on
finite clusters of an invariant percolation on transitive unimodular graphs are
derived. They are particularly suited for the case of critical Bernoulli
percolation and the associated heavy-tailed cluster size distributions. The
upper bound relies on the fact that cartesian products of finite graphs with
cycles of a certain minimal size are Hamiltonian. For critical Bernoulli bond
percolation on the homogeneous tree this bound is sharp. The asymptotic type of
the expected return probability for large times t in this case is of order of
the 3/4'th power of 1/t.


title:
Collective dynamical response of coupled oscillators with any network
  structure

abstract:
  We formulate a reduction theory that describes the response of an oscillator
network as a whole to external forcing applied nonuniformly to its constituent
oscillators. The phase description of multiple oscillator networks coupled
weakly is also developed. General formulae for the collective phase sensitivity
and the effective phase coupling between the oscillator networks are found. Our
theory is applicable to a wide variety of oscillator networks undergoing
frequency synchronization. Any network structure can systematically be treated.
A few examples are given to illustrate our theory.


title: Sub-Wavelength Resolution Imaging of the Solar Deep Interior

abstract:
  We derive expectations for signatures in the measured travel times of waves
that interact with thermal anomalies and jets. A series of numerical
experiments that involve the dynamic linear evolution of an acoustic wave field
in a solar-like stratified spherical shell in the presence of fully 3D
time-stationary perturbations are performed. The imprints of these interactions
are observed as shifts in wave travel times, which are extracted from these
data through methods of time-distance helioseismology \citep{duvall}. In
situations where at least one of the spatial dimensions of the scatterer was
smaller than a wavelength, oscillatory time shift signals were recovered from
the analyses, pointing directly to a means of resolving sub-wavelength
features. As evidence for this claim, we present analyses of simulations with
spatially localized jets and sound-speed perturbations. We analyze 1 years'
worth solar observations to estimate the noise level associated with the time
differences. Based on theoretical estimates, Fresnel zone time shifts
associated with the (possible) sharp rotation gradient at the base of the
convection zone are of the order 0.01 - 0.1 s, well below the noise level that
could be reached with the currently available amount of data ($\sim 0.15-0.2$ s
with 10 yrs of data).


title:
Leptogenesis Scenarios via Non-Thermally Produced Right-handed Neutrino
  and Sneutrino in Supersymmetric Seesaw Model

abstract:
  We reconsidered leptogenesis scenario from right-handed (s)neutrino produced
by the decay of inflaton. Besides the well-investigated case that the neutrino
decays instantaneously after the production, leptogenesis is possible if
neutrino decays after it dominates the universe. In the latter case,
right-handed (s)neutrino can decay either while it is relativistic or after it
becomes non-relativistic. Especially, the first case has not been discussed
seriously in literatures. Resultant lepton asymmetry and constraints from the
gravitino problem are studied in broad parameter region, including all cases of
this scenario. It is also shown how this leptogenesis scenario depends on the
parameters, the inflaton decay rate (the reheating temperature), the
right-handed neutrino mass, the washout parameter, and the constraint from the
gravitino problem. Leptogenesis from relativistic neutrino decay is interesting
because both thermal and non-thermal gravitino problems can be relaxed.


title: Testing Lorentz Invariance with Ultra High Energy Cosmic Ray Spectrum

abstract:
  The GZK cutoff predicted at the Ultra High Energy Cosmic Ray (UHECR) spectrum
as been observed by the HiRes and Auger experiments. The results put severe
constraints on the effect of Lorentz Invariance Violation(LIV) which has been
introduced to explain the absence of GZK cutoff indicated in the AGASA data.
Assuming homogeneous source distribution with a single power law spectrum, we
calculate the spectrum of UHECRs observed on Earth by taking the processes of
photopion production, $e^+e^-$ pair production and adiabatic energy loss into
account. The effect of LIV is also taken into account in the calculation. By
fitting the HiRes monocular spectra and the Auger combined spectra, we show
that the LIV parameter is constrained to $\xi=-0.8^{+3.2}_{-0.5}\times10^{-23}$
and $0.0^{+1.0}_{-0.4}\times10^{-23}$ respectively, which is well consistent
with strict Lorentz Invariance up to the highest energy.


title:
Geometric strong segregation theory for compositionally asymmetric
  diblock copolymer melts

abstract:
  We have identified the effect of the Wigner-Seitz cell geometry in the strong
segregation limit of diblock copolymer melts with strong composition asymmetry.
A variational problem is proposed describing the distortions of the chain paths
due to the geometric constraints imposed by the cell shape. We computed the
geometric excess energies for cylindrical phases arranged into hexagonal,
square, and triangular lattices and explicitly demonstrated that the hexagonal
lattice has the lowest energy for a fixed cell area.


title: On the Possibility of an Electronic-structure Modulation Transistor

abstract:
  We present a novel electronic-structure modulation transistor (EMT), which
can possibly be used for post-CMOS logic applications. The device principle is
based on the bandwidth modulation of a midgap or near-midgap localized state in
the channel by a gate voltage. A single-band tight-binding method coupled with
non-equilibrium Green's function formalism for quantum transport is employed to
predict the IV characteristics. Our objective is to confirm if an EMT has a
self gain and if it can overcome the 2.3kT/decade thermal limit with low supply
voltage. The ON current depends on the bandwidth of the state and is limited by
the quantum of conductance for a single band. The OFF current is set by the
gate leakage and tunneling through the higher bands, which is expected to be
small if these bands are a few eV above the energy level of the localized
state.


title: Possible Effects of Pair Echoes on Gamma-Ray Burst Afterglow Emission

abstract:
  High-energy emission from gamma-ray bursts (GRBs) is widely expected but had
been sparsely observed until recently when the Fermi satellite was launched. If
>TeV gamma rays are produced in GRBs and can escape from the emission region,
they are attenuated by the cosmic infrared background photons, leading to
regeneration of GeV-TeV secondary photons via inverse-Compton scattering. This
secondary emission can last for a longer time than the duration of GRBs, and it
is called a pair echo. We investigate how this pair echo emission affects
spectra and light curves of high energy afterglows, considering not only prompt
emission but also afterglow as the primary emission. Detection of pair echoes
is possible as long as the intergalactic magnetic field (IGMF) in voids is
weak. We find (1) that the pair echo from the primary afterglow emission can
affect the observed high-energy emission in the afterglow phase after the jet
break, and (2) that the pair echo from the primary prompt emission can also be
relevant, but only when significant energy is emitted in the TeV range,
typically E_{gamma, >0.1 TeV} > (Y/(1+Y)) epsilon_e E_k. Even non-detections of
the pair echoes could place interesting constraints on the strength of IGMF.
The more favorable targets to detect pair echoes may be the "naked" GRBs
without conventional afterglow emission, although energetic naked GRBs would be
rare. If the IGMF is weak enough, it is predicted that the GeV emission extends
to >30-300 s.


title: On Rank Problems for Planar Webs and Projective Structures

abstract:
  We present old and recent results on rank problems and linearizability of
geodesic planar webs.


title: 15 GHz VLBI detection of the HST-1 feature in the M87 jet

abstract:
  A bright feature 100 pc away from the core in the powerful jet of M 87 shows
mysterious properties. Earlier radio, optical and X-ray observations have shown
that this feature, labelled HST-1, is superluminal, and is possibly connected
with the TeV flare detected by HESS in 2005. To examine the possible
blazar-like nature of HST-1, we analyzed 2 cm VLBA data from dedicated
full-track observations and the 2 cm survey/MOJAVE VLBI monitoring programs
observed from 2000 to 2008. Applying wide-field imaging techniques, the HST-1
region was imaged at milliarcsecond resolutions. Here we present the first 15
GHz VLBI detection of this feature and discuss the connection between our radio
findings and the TeV detection.


title:
Phase diagrams of the Ising-Heisenberg chain with S=1/2 triangular XXZ
  clusters

abstract:
  The one dimensional spin system consisted of triangular $S=1/2$ $XXZ$
Heisenberg clusters alternating with single Ising spins is considered.
Partition function of the system is calculated exactly within the
transfer--matrix formalism. T=0 ground state phase diagrams, corresponding to
different regions of the values of system parameters are obtained.


title:
Quantum transfer matrix method for one-dimensional disordered electronic
  systems

abstract:
  We develop a novel quantum transfer matrix method to study thermodynamic
properties of one-dimensional (1D) disordered electronic systems. It is shown
that the partition function can be expressed as a product of $2\times2$ local
transfer matrices. We demonstrate this method by applying it to the 1D
disordered Anderson model. Thermodynamic quantities of this model are
calculated and discussed.


title: A simple proof of a theorem of Fukaya and Oh

abstract:
  We study the moduli space of pseudo pointed holomorphic disks with boundaries
mapped in the zero section of the cotangent bundle of a manifold. We define
perturbations of the equation for which it is possible to describe explicitly
all the solutions of the problem in terms of Morse graphs on the manifold. In
particular, this proves that the $A_\infty$ structure of the zero section of
the cotangent bundle is equivalent to the Morse $A_\infty$ structure of the
base manifold.


title:
Light Curve Morphology Study of UW CrB -- Evidence for a 5 d
  Superorbital Period

abstract:
  Since its discovery in 1990, UW CrB (also known as MS1603+2600) has remained
a peculiar source without firm classification. Our current understanding is
that it is an Accretion Disc Corona (ADC) low mass X-ray binary. In this paper
we present results from our photometric campaign dedicated to studying the
changing morphology of the optical light curves. We find that the optical light
curves show remarkable evidence for strongly evolving light curve shapes. In
addition we find that these changes show a modulation at a period of $\sim$ 5
days. We interpret these changes as either due to strong periodic accretion
disc warping or other geometrical changes due to disc precession at a period of
5 days. Finally, we have detected 11 new optical bursts, the phase distribution
of which supports the idea of a vertically extended asymmetric accretion disc.


title: Multiple intersection exponents

abstract:
  Let $p\ge2$, $n_1\le...\le n_p$ be positive integers and $B_1^1, ...,
B_{n_1}^1; ...; B_1^p, ..., B_{n_p}^{p}$ be independent planar Brownian motions
started uniformly on the boundary of the unit circle. We define a $p$-fold
intersection exponent $\varsigma(n_1,..., n_p)$, as the exponential rate of
decay of the probability that the packets $\bigcup_{j=1}^{n_i} B_j^i[0,t^2]$,
$i=1,...,p$, have no joint intersection. The case $p=2$ is well-known and,
following two decades of numerical and mathematical activity, Lawler, Schramm
and Werner (2001) rigorously identified precise values for these exponents. The
exponents have not been investigated so far for $p>2$. We present an extensive
mathematical and numerical study, leading to an exact formula in the case
$n_1=1$, $n_2=2$, and several interesting conjectures for other cases.


title: On-shell consistency of the Rarita-Schwinger field formulation

abstract:
  We prove that any bilinear coupling of a massive spin-3/2 field can be
brought into a gauge invariant form suggested by Pascalutsa by means of a
non-linear field redefinition. The corresponding field transformation is given
explicitly in a closed form and the implications for chiral effective field
theory with explicit Delta (1232) isobar degrees of freedom are discussed.


title: Diamond chains with multiple-spin exchange interactions

abstract:
  We study the phase diagram of a symmetric spin-1/2 Heisenberg diamond chain
with additional cyclic four-spin exchange interactions. The presented analysis
supplemented by numerical exact-diagonalization results for finite periodic
clusters implies a rich phase diagram containing, apart from standard magnetic
and spin-liquid phases, two different tetramer-dimer phases as well as an
exotic four-fold degenerate dimerized phase. The characteristics of the
established spin phases as well as the nature of quantum phase transitions are
discussed, as well.


title: Monopole blocking governed by a modified KdV type equation

abstract:
  A type of coupled variable coefficient modified Korteweg-de Vries system is
derived from a two-layered fluid system. It is known that the formation,
maintenance, and collapse of an atmospheric blocking are always related with
large-scale weather or shorts term climate anomalies. One special analytical
solution of the obtained system successfully features the evolution cycle of an
atmospheric monopole type blocking event. In particular, our theoretical
results captures a real monopole type blocking case happened during 19 Feb 2008
to 26 Feb 2008 can be well described by our analytical solution.


title:
Antiferromagnet-based nuclear spin model of scalable quantum register
  with inhomogeneous magnetic field

abstract:
  As a nuclear spin model of scalable quantum register, the one-dimensional
chain of the magnetic atoms with nuclear spins 1/2 substituting the basic atoms
in the plate of nuclear spin free easy-axis 3D antiferromagnet is considered.
It is formulated the generalized antiferromagnet Hamiltonian in spin-wave
approximation (low temperatures) considering the inhomogeneous external
magnetic field, which is directed along the easy axis normally to plane of the
plate and has a constant gradient along the nuclear spin chain. Assuming a weak
gradient, the asymptotic expression for coefficients of unitary transformations
to the diagonal form of antiferromagnet Hamiltonian is found. With this result
the expression for indirect interspin coupling, which is due to hyperfine
nuclear electron coupling in atoms and the virtual spin wave propagation in
antiferromagnet ground state, was evaluated.
  It is shown that the inhomogeneous magnetic field essentially modifies the
characteristics of indirect interspin coupling. The indirect interaction
essentially grows and even oscillates in relation to the interspin distance
when the local field value in the middle point of two considered nuclear spin
is close to the critical field for quantum phase transition of spin-flop type
in bulk antiferromagnet or close to antiferromagnetic resonance. Thus, the
external magnetic field, its gradient, microwave frequency and power can play
the role of control parameters for qubit states.
  Finally, the one and two qubit states decoherence and longitudinal relaxation
rate are caused by the interaction of nuclear spins with virtual spin waves in
antiferromagnet ground state are calculated.


title:
A mixed relaxed singular maximum principle for linear SDEs with random
  coefficients

abstract:
  We study singular stochastic control of a two dimensional stochastic
differential equation, where the first component is linear with random and
unbounded coefficients. We derive existence of an optimal relaxed control and
necessary conditions for optimality in the form of a mixed relaxed-singular
maximum principle in a global form. A motivating example is given in the form
of an optimal investment and consumption problem with transaction costs, where
we consider a portfolio with a continuum of bonds and where the portfolio
weights are modeled as measure-valued processes on the set of times to
maturity.


title:
Two dimensional frustrated magnetic state in superconducting
  RuSr2Eu1.5Ce0.5Cu2O10 (Ru-1222)

abstract:
  In this paper we investigate the magnetic state and the role of the
crystalline structure in RuSr2Eu1.5Ce0.5Cu2O10 (Ru-1222). Measurements were
made in the isomorphic series (Nb1-xRux)Sr2Eu1.5Ce0.5Cu2O10 [(Nb,Ru)-1222],
with x between 0 and 1. 3D XY fluctuations above the magnetic transition were
not observed in Ru-1222, suggesting a weak inter-plane coupling between the
RuO2 layers. The compositional dependence of the magnetic susceptibility shows
a rapid broadening with increasing Nb content, explained in terms of a
cluster-glass state. The variation of several superconducting parameters as a
function of Ru content is linear in the whole concentration range, with no
jumps at the critical concentration for which percolation of long range order
is expected. 3D Arrhenius and Vogel-Fulcher-type dependencies fail to describe
the dynamic properties. Fitting of a generalized Vogel-Fulcher-type dependence,
with ln(tau/tau0) = A(T-T0)^-B, yield B = 2.0, in excellent agreement with
Monte Carlo simulations for 2D systems. The value deduced for T0 agrees well
with the re-opening of hysteresis in the M(H) curves. The observed
superconducting and magnetic features are explained in terms of a scenario of
2D magnetic islands at the RuO2 layers, with no long range magnetic order.


title:
Analyzing the Effects of Neutron Polarizabilities in Elastic Compton
  Scattering off ${}^3$He

abstract:
  Motivated by the fact that a polarized ${}^3$He nucleus behaves as an
`effective' neutron target, we examine manifestations of neutron
electromagnetic polarizabilities in elastic Compton scattering from the
Helium-3 nucleus. We calculate both unpolarized and double-polarization
observables using chiral perturbation theory to next-to-leading order
(${\mathcal O}(e^2 Q)$) at energies, $\omega \leq m_{\pi}$, where $m_{\pi}$ is
the pion mass. Our results show that the unpolarized differential cross section
can be used to measure neutron electric and magnetic polarizabilities, while
two double-polarization observables are sensitive to different linear
combinations of the four neutron spin polarizabilities.
  [Note added in 2018] The qualitative conclusions and analytic formulae
presented in this paper are correct, but several of the numerical results are
wrong: see the erratum posted as arXiv:1804.01206 for further details. A full
suite of corrected numerical results for cross sections and asymmetries can be
found in Margaryan et al., arXiv:1804.00956. They can also be obtained as an
interactive Mathematica notebook by emailing hgrie@gwu.edu.


title: Spin control in semiconductor quantum wires

abstract:
  We show that spin-flip rotation in a semiconductor quantum wire, caused by
the Rashba and the Dresselhaus interactions (both of arbitrary strengths), can
be suppressed by dint of an in-plane magnetic field. We found a new type of
symmetry, which arises at a particular set of intensity and orientation of the
magnetic field and explains this suppression. Based on our findings, we propose
a transport experiment to measure the strengths of the Rashba and the
Dresselhaus interactions.


title: Homotopy Equivalences induced by Balanced Pairs

abstract:
  We introduce the notion of balanced pair of additive subcategories in an
abelian category. We give sufficient conditions under which the balanced pair
of subcategories gives rise to equivalent homotopy categories of complexes. As
an application, we prove that for a left-Gorenstein ring, there exists a
triangle-equivalence between the homotopy category of its Gorenstein projective
modules and the homotopy category of its Gorenstein injective modules, which
restricts to a triangle-equivalence between the homotopy category of projective
modules and the homotopy category of injective modules. In the case of
commutative Gorenstein rings we prove that up to a natural isomorphism our
equivalence extends Iyengar-Krause's equivalence.


title:
A generalised Measurement Equation and van Cittert-Zernike theorem for
  wide-field radio astronomical interferometry

abstract:
  We derive a generalised van Cittert-Zernike (vC-Z) theorem for radio
astronomy that is valid for partially polarized sources over an arbitrarily
wide field-of-view (FoV). The classical vC-Z theorem is the theoretical
foundation of radio astronomical interferometry, and its application is the
basis of interferometric imaging. Existing generalised vC-Z theorems in radio
astronomy assume, however, either paraxiality (narrow FoV) or scalar
(unpolarized) sources. Our theorem uses neither of these assumptions, which are
seldom fulfilled in practice in radio astronomy, and treats the full
electromagnetic field. To handle wide, partially polarized fields, we extend
the two-dimensional electric field (Jones vector) formalism of the standard
"Measurement Equation" of radio astronomical interferometry to the full
three-dimensional formalism developed in optical coherence theory. The
resulting vC-Z theorem enables all-sky imaging in a single telescope pointing,
and imaging using not only standard dual-polarized interferometers (that
measure 2-D electric fields), but also electric tripoles and electromagnetic
vector-sensor interferometers. We show that the standard 2-D Measurement
Equation is easily obtained from our formalism in the case of dual-polarized
antenna element interferometers. We find, however, that such dual-polarized
interferometers can have polarimetric aberrations at the edges of the FoV that
are often correctable. Our theorem is particularly relevant to proposed and
recently developed wide FoV interferometers such as LOFAR and SKA, for which
direction-dependent effects will be important.


title:
Optical vortex soliton with self-defocusing Kerr-type nonlocal
  nonlinearity

abstract:
  We develop one numerical method to compute the optical vortex soliton with
self-defocusing Kerr-type nonlocal nonlinearity. With the numerical simulation
method, the propagation and interaction properties of such optical vortex
solitons are investigated.


title: Permutations sortable by n-4 passes through a stack

abstract:
  We characterise and enumerate permutations that are sortable by n-4 passes
through a stack. We conjecture the number of permutations sortable by n-5
passes, and also the form of a formula for the general case n-k, which involves
a polynomial expression.


title: Overview of Kbar-N and Kbar-nucleus dynamics

abstract:
  The main features of coupled-channel Kbar-N dynamics near threshold and its
repercussions in few-body Kbar-nuclear systems are briefly reviewed
highlighting the I=1/2 Kbar-N-N system. For heavier nuclei, the extension of
mean-field calculations to multi-Kbar nuclear quasibound states is discussed
focusing on kaon condensation.


title:
Suzaku Results on the Obscured Low-Luminosity Active Galactic Nucleus in
  NGC 4258

abstract:
  In 2006 June, the obscured low luminosity active galactic nucleus in the
nearby Seyfert 1.9 galaxy NGC 4258 was observed with Suzaku for ~ 100 ks.
Utilizing the XIS and the HXD, the nucleus emission was detected over 2 to 40
keV range, with an unabsorbed 2--10 keV luminosity of 8 x 10 40 erg / s, and
varied by a factor of ~ 2 during the observation. Its 2--40 keV spectrum is
reproduced by a single power law with photon index of ~ 2.0, absorbed by an
equivalent hydrogen column of ~ 1.0 x 10 23 cm2. The spectrum within 4' of the
nucleus required also a softer thin-thermal emission, as well as an
intermediate hardness component attributable to integrated point sources. A
weak neutral Fe-Kalpha florescence line was detected at an equivalent width of
~ 40 eV. The cold reflection component was not required by the data, with the
reflector solid angle Omega seen from the nucleus constrained as Omega / 2 pi <
0.3 assuming a general case of 60 deg inclination. The results suggest that the
cold reflecting material around the nucleus is localized along our line of
sight, rather than forming a thick torus.


title:
Lower Bounds on Performance of Metric Tree Indexing Schemes for Exact
  Similarity Search in High Dimensions

abstract:
  Within a mathematically rigorous model, we analyse the curse of
dimensionality for deterministic exact similarity search in the context of
popular indexing schemes: metric trees. The datasets $X$ are sampled randomly
from a domain $\Omega$, equipped with a distance, $\rho$, and an underlying
probability distribution, $\mu$. While performing an asymptotic analysis, we
send the intrinsic dimension $d$ of $\Omega$ to infinity, and assume that the
size of a dataset, $n$, grows superpolynomially yet subexponentially in $d$.
Exact similarity search refers to finding the nearest neighbour in the dataset
$X$ to a query point $\omega\in\Omega$, where the query points are subject to
the same probability distribution $\mu$ as datapoints. Let $\mathscr F$ denote
a class of all 1-Lipschitz functions on $\Omega$ that can be used as decision
functions in constructing a hierarchical metric tree indexing scheme. Suppose
the VC dimension of the class of all sets $\{\omega\colon f(\omega)\geq a\}$,
$a\in\R$ is $o(n^{1/4}/\log^2n)$. (In view of a 1995 result of Goldberg and
Jerrum, even a stronger complexity assumption $d^{O(1)}$ is reasonable.) We
deduce the $\Omega(n^{1/4})$ lower bound on the expected average case
performance of hierarchical metric-tree based indexing schemes for exact
similarity search in $(\Omega,X)$. In paricular, this bound is superpolynomial
in $d$.


title:
Complete convergence of message passing algorithms for some
  satisfiability problems

abstract:
  In this paper we analyze the performance of Warning Propagation, a popular
message passing algorithm. We show that for 3CNF formulas drawn from a certain
distribution over random satisfiable 3CNF formulas, commonly referred to as the
planted-assignment distribution, running Warning Propagation in the standard
way (run message passing until convergence, simplify the formula according to
the resulting assignment, and satisfy the remaining subformula, if necessary,
using a simple "off the shelf" heuristic) results in a satisfying assignment
when the clause-variable ratio is a sufficiently large constant.


title:
Silicon as a model ion trap: time domain measurements of donor Rydberg
  states

abstract:
  One of the great successes of quantum physics is the description of the
long-lived Rydberg states of atoms and ions. The Bohr model is equally
applicable to donor impurity atoms in semiconductor physics, where the
conduction band corresponds to the vacuum, and the loosely bound electron
orbiting a singly charged core has a hydrogen-like spectrum according to the
usual Bohr-Sommerfeld formula, shifted to the far-infrared due to the small
effective mass and high dielectric constant. Manipulation of Rydberg states in
free atoms and ions by single and multi-photon processes has been tremendously
productive since the development of pulsed visible laser spectroscopy. The
analogous manipulations have not been conducted for donor impurities in
silicon. Here we use the FELIX pulsed free electron laser to perform
time-domain measurements of the Rydberg state dynamics in phosphorus- and
arsenic-doped silicon and we have obtained lifetimes consistent with frequency
domain linewidths for isotopically purified silicon. This implies that the
dominant decoherence mechanism for excited Rydberg states is lifetime
broadening, just as for atoms in ion traps. The experiments are important
because they represent the first step towards coherent control and manipulation
of atomic-like quantum levels in the most common semiconductor and complement
magnetic resonance experiments in the literature, which show extraordinarily
long spin lattice relaxation times key to many well-known schemes for quantum
computing qubits for the same impurities. Our results, taken together with the
magnetic resonance data and progress in precise placement of single impurities,
suggest that doped silicon, the basis for modern microelectronics, is also a
model ion trap.


title:
Entire solutions of hydrodynamical equations with exponential
  dissipation

abstract:
  We consider a modification of the three-dimensional Navier--Stokes equations
and other hydrodynamical evolution equations with space-periodic initial
conditions in which the usual Laplacian of the dissipation operator is replaced
by an operator whose Fourier symbol grows exponentially as $\ue ^{|k|/\kd}$ at
high wavenumbers $|k|$. Using estimates in suitable classes of analytic
functions, we show that the solutions with initially finite energy become
immediately entire in the space variables and that the Fourier coefficients
decay faster than $\ue ^{-C(k/\kd) \ln (|k|/\kd)}$ for any $C<1/(2\ln 2)$. The
same result holds for the one-dimensional Burgers equation with exponential
dissipation but can be improved: heuristic arguments and very precise
simulations, analyzed by the method of asymptotic extrapolation of van der
Hoeven, indicate that the leading-order asymptotics is precisely of the above
form with $C= C_\star =1/\ln2$. The same behavior with a universal constant
$C_\star$ is conjectured for the Navier--Stokes equations with exponential
dissipation in any space dimension. This universality prevents the strong
growth of intermittency in the far dissipation range which is obtained for
ordinary Navier--Stokes turbulence. Possible applications to improved spectral
simulations are briefly discussed.


title: Enrichments over symmetric Picard categories

abstract:
  Categorical rings were introduced by Jibladze and Pirashvili in their paper
"Third Mac Lane cohomology via categorical rings", Journal of Homotopy and
related structures, 2, 2007, 187-216. We call those "2-rings". In these notes
we present basic definitions and results regarding 2-modules. This is work in
progress.


title: A volume form on the Khovanov invariant

abstract:
  The Reidemeister torsion construction can be applied to the chain complex
used to compute the Khovanov homology of a knot or a link. This defines a
volume form on Khovanov homology. The volume form transforms correctly under
Reidemeister moves to give an invariant volume on the Khovanov homology. In
this paper, its construction and invariance under these moves is demonstrated.
Also, some examples of the invariant are presented for particular choices for
the bases of homology groups to obtain a numerical invariant of knots and
links. In these examples, the algebraic torsion seen in the Khovanov chain
complex when homology is computed over $\mathbb{Z}$ is recovered.


title: Duality in linearized gravity and holography

abstract:
  We consider spherical gravitational perturbations of AdS4 space-time
satisfying general boundary conditions at spatial infinity. Using the
holographic renormalization method, we compute the energy-momentum tensor and
show that it can always be cast in the form of Cotton tensor for a dual
boundary metric. In particular, axial and polar perturbations obeying the same
boundary conditions for the effective Schrodinger wave-functions exhibit an
energy-momentum/Cotton tensor duality at conformal infinity. We demonstrate
explicitly that this is holographic manifestation of the electric/magnetic
duality of linearized gravity in the bulk, which simply exchanges axial with
polar perturbations of AdS4 space-time. We note on the side that this
particular realization of gravitational duality is also valid for perturbations
near flat and dS4 space-time, depending on the value of cosmological constant.


title:
Stochastic Line-Motion and Stochastic Conservation Laws for Non-Ideal
  Hydromagnetic Models. I. Incompressible Fluids and Isotropic Transport
  Coefficients

abstract:
  We prove that smooth solutions of non-ideal (viscous and resistive)
incompressible magnetohydrodynamic equations satisfy a stochastic law of flux
conservation. This property involves an ensemble of surfaces obtained from a
given, fixed surface by advecting it backward in time under the plasma velocity
perturbed with a random white-noise. It is shown that the magnetic flux through
the fixed surface is equal to the average of the magnetic fluxes through the
ensemble of surfaces at earlier times. This result is an analogue of the
well-known Alfven theorem of ideal MHD and is valid for any value of the
magnetic Prandtl number. A second stochastic conservation law is shown to hold
at unit Prandtl number, a random version of the generalized Kelvin theorem
derived by Bekenstein-Oron for ideal MHD. These stochastic conservation laws
are not only shown to be consequences of the non-ideal MHD equations, but are
proved in fact to be equivalent to those equations. We derive similar results
for two more refined hydromagnetic models, Hall magnetohydrodynamics and the
two-fluid plasma model, still assuming incompressible velocities and isotropic
transport coefficients. Finally, we use these results to discuss briefly the
infinite-Reynolds-number limit of hydromagnetic turbulence and to support the
conjecture that flux-conservation remains stochastic in that limit.


title: Homotopy theory of C*-algebras

abstract:
  In this work we construct from ground up a homotopy theory of C*-algebras.
This is achieved in parallel with the development of classical homotopy theory
by first introducing an unstable model structure and second a stable model
structure. The theory makes use of a full fledged import of homotopy theoretic
techniques into the subject of C*-algebras.
  The spaces in C*-homotopy theory are certain hybrids of functors represented
by C*-algebras and spaces studied in classical homotopy theory. In particular,
we employ both the topological circle and the C*-algebra circle of
complex-valued continuous functions on the real numbers which vanish at
infinity. By using the inner workings of the theory, we may stabilize the
spaces by forming spectra and bispectra with respect to either one of these
circles or their tensor product. These stabilized spaces or spectra are the
objects of study in stable C*-homotopy theory.
  The stable homotopy category of C*-algebras gives rise to invariants such as
stable homotopy groups and bigraded cohomology and homology theories. We work
out examples related to the emerging subject of noncommutative motives and zeta
functions of C*-algebras. In addition, we employ homotopy theory to define a
new type of K-theory of C*-algebras.


title:
Universal versus Material-Dependent Two-Gap Behaviors in the High-Tc
  Cuprates: Angle-Resolved Photoemission Study of La2-xSrxCuO4

abstract:
  We have investigated the doping and temperature dependences of the
pseudogap/superconducting gap in the single-layer cuprate
La$_{2-x}$Sr$_x$CuO$_4$ by angle-resolved photoemission spectroscopy. The
results clearly exhibit two distinct energy and temperature scales, namely, the
gap around ($\pi$,0) of magnitude $\Delta^*$ and the gap around the node
characterized by the d-wave order parameter $\Delta_0$, like the double-layer
cuprate Bi2212. In comparison with Bi2212 having higher $T_c$'s, $\Delta_0$ is
smaller, while $\Delta^*$ and $T^*$ are similar. This result suggests that
$\Delta^*$ and $T^*$ are approximately material-independent properties of a
single CuO$_2$ plane, in contrast the material-dependent $\Delta_0$,
representing the pairing strength.


title: Pattern Recognition on Oriented Matroids: Three-Tope Committees

abstract:
  A three-tope committee K* for a simple oriented matroid M is a 3-subset of
its maximal covectors such that every positive halfspace of M contains at least
two topes from K*. We consider three-tope committees as the vertex sets of
triangles in graphs associated with the topes and enumerate them making use of
the properties of the poset of convex subsets of the ground set of M.


title: Distributed self-regulation of living tissue. Effects of nonideality

abstract:
  Self-regulation of living tissue as an example of self-organization phenomena
in active fractal systems of biological, ecological, and social nature is under
consideration. The characteristic feature of these systems is the absence of
any governing center and, thereby, their self-regulation is based on a
cooperative interaction of all the elements. The paper develops a mathematical
theory of a vascular network response to local effects on scales of individual
units of peripheral circulation.
  First, it formulates a model for the self-processing of information about the
cellular tissue state and cooperative interaction of blood vessels governing
redistribution of blood flow over the vascular network. Mass conservation
(conservation of blood flow as well as transported biochemical compounds) plays
the key role in implementing these processes. The vascular network is
considered to be of the tree form and the blood vessels are assumed to respond
individually to an activator in blood flowing though them.
  Second, the constructed governing equations are analyzed numerically. It is
shown that at the first approximation the blood perfusion rate depends locally
on the activator concentration in the cellular tissue, which is due to the
hierarchical structure of the vascular network. Then the distinction between
the reaction threshold of individual vessels and that of the vascular network
as a whole is demonstrated. In addition, the nonlocal component of the
dependence of the blood perfusion rate on the activator concentration is found
to change its form as the activator concentration increases.


title:
Effect of a in-plane magnetic field on the microwave assisted
  magnetotransport in a two-dimensional electron system

abstract:
  In this work we present a theoretical approach to study the effect of an
in-plane (parallel) magnetic field on the microwave-assisted transport
properties of a two-dimensional electron system. Previous experimental
evidences show that microwave-induced resistance oscillations and zero
resistance states are differently affected depending on the experimental
set-up: two magnetic fields (two-axis magnet) or one tilted magnetic field. In
the first case, experiments report a clear quenching of resistance oscillations
and zero resistance states. In a tilted field, one obtains oscillations
displacement and quenching but the latter is unbalanced and less intense. In
our theoretical proposal we explain these results in terms of the
microwave-driven harmonic motion performed by the electronic orbits and how
this motion is increasingly damped by the in-plane field.


title: Optimal sequential procedures with Bayes decision rules

abstract:
  In this article, a general problem of sequential statistical inference for
general discrete-time stochastic processes is considered. The problem is to
minimize an average sample number given that Bayesian risk due to incorrect
decision does not exceed some given bound. We characterize the form of optimal
sequential stopping rules in this problem. In particular, we have a
characterization of the form of optimal sequential decision procedures when the
Bayesian risk includes both the loss due to incorrect decision and the cost of
observations.


title:
Tumor suppressor and anti-inflammatory protein: an expanded view on
  insulin-degrading enzyme (IDE)

abstract:
  In 1994, I conjectured that insulin-degrading enzyme (IDE) acts as an
inhibitor of malignant transformation by degrading insulin and thus preventing
this major growth-stimulatory hormone from binding and thereby inactivating the
retinoblastoma tumor suppressor protein (RB). Ten years later, I discovered
that a carboxyterminal RB amino acid sequence resembles the catalytic center of
IDE. This structural homology raised the possibility that insulin degradation
is a basic mechanism for tumor suppression shared by RB and IDE. Subsequently,
a first immunohistochemical study on the differential expression of human IDE
in normal tissues, primary tumors and their corresponding lymph node metastases
further corroborated the initial conjecture on IDE being an antineoplastic
molecule. In this report, it is shown that IDE harbors ankyrin repeat-like
amino acid sequences through which it might bind and, as a result, antagonize
the pro-inflammatory factor NF-kappaB as well as cyclin-dependent kinases
(CDKs). As equally revealed here, IDE also contains 2 RXL cyclin-binding motifs
which could contribute to its presumed inhibition of CDKs. These new findings
suggest that IDE is potentially able to suppress both inflammation and
oncogenesis by several mechanisms that ultimately ensure RB function.


title:
Dual descriptions of spin two massive particles in $D=2+1$ via master
  actions

abstract:
  In the first part of this work we show the decoupling (up to contact terms)
of redundant degrees of freedom which appear in the covariant description of
spin two massive particles in $D=2+1$. We make use of a master action which
interpolates, without solving any constraints, between a first, second and
third order (in derivatives) self-dual model. An explicit dual map between
those models is derived. In our approach the absence of ghosts in the third
order self-dual model, which corresponds to a quadratic truncation of
topologically massive gravity, is due to the triviality (no particle content)
of the Einstein-Hilbert action in $D=2+1$. In the second part of the work, also
in $D=2+1$, we prove the quantum equivalence of the gauge invariant sector of a
couple of self-dual models of opposite helicities (+2 and -2) and masses $m_+$
and $m_-$ to a generalized self-dual model which contains a quadratic
Einstein-Hilbert action, a Chern-Simons term of first order and a Fierz-Pauli
mass term. The use of a first order Chern-Simons term instead of a third order
one avoids conflicts with the sign of the Einstein-Hilbert action.


title: Homogeneous Lagrangian submanifolds of positive Euler characteristic

abstract:
  We fully classify all Lagrangian submanifolds of a complex Grassmannian which
are an orbit of a compact group of isometries and have positive Euler
characteristic.


title:
The UKIDSS-2MASS Proper Motion Survey I: Ultracool dwarfs from UKIDSS
  DR4

abstract:
  The UKIRT Infrared Deep Sky Survey (UKIDSS) is the first of a new generation
of infrared surveys. Here we combine the data from two UKIDSS components, the
Large Area Survey (LAS) and the Galactic Cluster Survey (GCS), with 2MASS data
to produce an infrared proper motion survey for low mass stars and brown
dwarfs. In total we detect 267 low mass stars and brown dwarfs with significant
proper motions. We recover all ten known single L dwarfs and the one known T
dwarf above the 2MASS detection limit in our LAS survey area and identify eight
additional new candidate L dwarfs. We also find one new candidate L dwarf in
our GCS sample. Our sample also contains objects from eleven potential common
proper motion binaries. Finally we test our proper motions and find that while
the LAS objects have proper motions consistent with absolute proper motions,
the GCS stars may have proper motions which are significantly under-estimated.
This is due possibly to the bulk motion of some of the local astrometric
reference stars used in the proper motion determination.


title:
Factor complexity of infinite words associated with non-simple Parry
  numbers

abstract:
  The factor complexity of the infinite word $\ubeta$ canonically associated to
a non-simple Parry number $\beta$ is studied. Our approach is based on the
notion of special factors introduced by Berstel and Cassaigne. At first, we
give a handy method for determining infinite left special branches; this method
is applicable to a broad class of infinite words which are fixed points of a
primitive substitution. In the second part of the article, we focus on infinite
words $\ubeta$ only. To complete the description of its special factors, we
define and study $(a,b)$-maximal left special factors. This enables us to
characterize non-simple Parry numbers $\beta$ for which the word $\ubeta$ has
affine complexity.


title: The Uncanny Precision of the Spectral Action

abstract:
  Noncommutative geometry has been slowly emerging as a new paradigm of
geometry which starts from quantum mechanics. One of its key features is that
the new geometry is spectral in agreement with the physical way of measuring
distances. In this paper we present a detailed introduction with an overview on
the study of the quantum nature of space-time using the tools of noncommutative
geometry. In particular we examine the suitability of using the spectral action
as action functional for the theory. To demonstrate how the spectral action
encodes the dynamics of gravity we examine the accuracy of the approximation of
the spectral action by its asymptotic expansion in the case of the round three
sphere. We find that the two terms corresponding to the cosmological constant
and the scalar curvature term already give the full result with remarkable
accuracy. This is then applied to the physically relevant case of the product
of the three sphere by a circle where we show that the spectral action in this
case is also given, for any test function, by the sum of two terms up to an
astronomically small correction, and in particular all higher order terms
vanish. This result is confirmed by evaluating the spectral action using the
heat kernel expansion where we check that the higher order terms a4 and a6 both
vanish due to remarkable cancelations. We also show that the Higgs potential
appears as an exact perturbation when the test function used is a smooth cutoff
function.


title: 1/N Effects in Non-Relativistic Gauge-Gravity Duality

abstract:
  We argue that higher-curvature terms in the gravitational Lagrangian lead,
via non-relativistic gauge-gravity duality, to finite renormalization of the
dynamical exponent of the dual conformal field theory. Our argument includes a
proof of the non-renormalization of the Schrodinger and Lifshitz metrics beyond
rescalings of their parameters, directly generalizing the AdS case. We use this
effect to construct string-theory duals of non-relativistic critical systems
with non-integer dynamical exponents, then use these duals to predict the
viscosity/entropy ratios of these systems. The predicted values weakly violate
the KSS bound.


title:
A scaling law for the cosmological constant from a stochastic model for
  cosmic structures

abstract:
  A set of scaling laws, based on the stochastic motions of the granular
components of astronomical systems, is applied to a cosmological model with a
positive cosmological constant. It follows that the mass of the dominant
particle in the observable universe must be proportional to the sixth root of
the cosmological constant and of the order of the nucleon mass, which is
consistent with the Zeldovich scaling law. The approach is a natural way to
solve the cosmic coincidence problem. On the other hand, the observed value of
the cosmological constant emerges as the result of a scaling law induced by the
stochastic mechanism which gives rise to the gravitationally bound systems.


title:
Stochastic Background of Gravitational Waves as a Benchmark for Extended
  Theories of Gravity

abstract:
  The cosmological background of gravitational waves can be tuned by Extended
Theories of Gravity. In particular, it can be shown that assuming a generic
function f(R) of the Ricci scalar R gives a parametric approach to control the
evolution and the production mechanism of gravitational waves in the early
Universe.


title: Quantum Field Theories on Algebraic Curves. I. Additive bosons

abstract:
  Using Serre's adelic interpretation of cohomology, we develop a `differential
and integral calculus' on an algebraic curve X over an algebraically closed
filed k of constants of characteristic zero, define algebraic analogs of
additive multi-valued functions on X and prove corresponding generalized
residue theorem. Using the representation theory of the global Heisenberg and
lattice Lie algebras, we formulate quantum field theories of additive and
charged bosons on an algebraic curve X. These theories are naturally connected
with the algebraic de Rham theorem. We prove that an extension of global
symmetries (Witten's additive Ward identities) from the k-vector space of
rational functions on X to the vector space of additive multi-valued functions
uniquely determines these quantum theories of additive and charged bosons.


title: Dark energy towards observational tests and data

abstract:
  A huge amount of good quality data converges towards the picture of a
spatially flat universe undergoing the today observed phase of accelerated
expansion. This new observational trend is commonly addressed as Precision
Cosmology. Despite of the excellent surveys, the nature of dark energy,
dominating the matter-energy content of the universe, is still unknown and a
lot of different scenarios are viable candidates to explain cosmic
acceleration. Methods to test these cosmological models are based on distance
measurements and lookback time toward astronomical objects used as standard
candles. The related degeneracy problem is the signal that more data at low
0<z<1, medium 1<z<10 and high 10 <z< 1000 redshift are needed to definitively
select realistic models.


title:
On the inapplicability of a negative-phase-velocity condition as a
  negative-refraction condition for active materials

abstract:
  A negative-phase-velocity condition derived by Depine and Lakhtakia
[Microwave Opt Technol Lett 41 (2004) 315] for isotropic, homogeneous, passive,
dielectric-magnetic materials is inapplicable as a negative-refraction
condition for active materials.


title: The Inverse of a Nearly Banded Matrix

abstract:
  A quantitative form of the Nullity Theorem is presented, which establishes a
linear relation between the singular values of the two submatrices involved in
the theorem up to the first order. The theorem is then extended to function
spaces and a corresponding form in infinite dimension is discussed.


title: A Note on Distributional Semi-Riemannian Geometry

abstract:
  We discuss some basic concepts of semi-Riemannian geometry in low-regularity
situations. In particular, we compare the settings of (linear) distributional
geometry in the sense of L. Schwartz and nonlinear distributional geometry in
the sense of J.F. Colombeau.


title: Magnetic Moment Formulas of Baryons Determined by Quantum Numbers

abstract:
  We propose that the magnetic moment formulas of baryons may be determined by
quantum numbers, and obtain three formulas. This is a new type of magnetic
moment formula, and agrees better with the experimental values. It is also
similar to corresponding mass formulas of hadrons.


title: New F-theory lifts

abstract:
  In this note, a procedure is developed to explicitly construct non-trivial
F-theory lifts of perturbative IIB orientifold models on Calabi-Yau complete
intersections in toric varieties. This procedure works on Calabi-Yau
orientifolds where the involution coordinate can have arbitrary projective
weight, as opposed to the well-known hypersurface cases where it has half the
weight of the equation defining the CY threefold. This opens up the possibility
of lifting more general setups, such as models that have O3-planes.


title: PT Symmetry and QCD: Finite Temperature and Density

abstract:
  The relevance of PT symmetry to quantum chromodynamics (QCD), the gauge
theory of the strong interactions, is explored in the context of finite
temperature and density. Two significant problems in QCD are studied: the sign
problem of finite-density QCD, and the problem of confinement. It is proven
that the effective action for heavy quarks at finite density is PT-symmetric.
For the case of 1+1 dimensions, the PT-symmetric Hamiltonian, although not
Hermitian, has real eigenvalues for a range of values of the chemical potential
$\mu$, solving the sign problem for this model. The effective action for heavy
quarks is part of a potentially large class of generalized sine-Gordon models
which are non-Hermitian but are PT-symmetric. Generalized sine-Gordon models
also occur naturally in gauge theories in which magnetic monopoles lead to
confinement. We explore gauge theories where monopoles cause confinement at
arbitrarily high temperatures. Several different classes of monopole gases
exist, with each class leading to different string tension scaling laws. For
one class of monopole gas models, the PT-symmetric affine Toda field theory
emerges naturally as the effective theory. This in turn leads to sine-law
scaling for string tensions, a behavior consistent with lattice simulations.


title: Loop Quantum Cosmology: An Overview

abstract:
  A brief overview of loop quantum cosmology of homogeneous isotropic models is
presented with emphasis on the origin of and subtleties associated with the
resolution of big bang and big crunch singularities. These results bear out the
remarkable intuition that John Wheeler had. Discussion is organized at two
levels. The the main text provides a bird's eye view of the subject that should
be accessible to non-experts. Appendices address conceptual and technical
issues that are often raised by experts in loop quantum gravity and string
theory.


title:
Molecular gas and star formation in the red-sequence counter-rotating
  disc galaxy NGC 4550

abstract:
  We present observations of the CO(1-0) emission in the central 750 pc (10
arcsec) of the counter-rotating disc galaxy NGC 4550, obtained at the Institut
de Radioastronomie Millimetrique (IRAM) Plateau de Bure Interferometer. Very
little molecular gas is detected, only 1 x 10^7 solar masses, and its
distribution is lopsided, with twice as much molecular gas observed at positive
relative velocities than at negative relative velocities. The velocity gradient
in the CO(1-0) emission shows that the molecular gas rotates like the thicker
of the two stellar discs, which is an unexpected alignment of rotations if the
thinner disc was formed by a major gas accretion event. However, a simulation
shows that the gas rotating like the thicker disc naturally results from the
coplanar merger of two counter-rotating disc galaxies, demonstrating the
feasibility of this scenario for the formation of NGC 4550. We investigate
various star formation tracers to determine whether the molecular gas in NGC
4550 is currently forming stars. UV imaging data and optical absorption
linestrengths both suggest a recent star formation episode; the best-fitting
two population model to the UV-optical colours yields a mass of young stars of
5.9 x 10^7 solar masses with an age of 280 Myr. The best information on the
current star formation rate is a far infrared-based upper limit of only 0.02
solar masses per year. We are thus witnessing NGC 4550 either in a dip within a
bursty star formation period or during a more continuous low-level star
formation episode.


title: Traces on Hecke algebras and families of p-adic modular forms

abstract:
  In this preprint we prove that any finite slope modular form fits into a
p-adic family of modular forms which is indexed by the weight. Here, the term
p-adic family means that p-adic congruences between weights entail certain
p-adic congruences between the corresponding modular forms. We also show that
the dimension of the slope subspace of the space of modular forms does not
depend on the weight. Both statements are predicted by the Mazur-Gouvea
Conjecture, which has been proven by Coleman using methods from rigid analytic
geometry. In contrast our proof is based on a comparison of (topological) trace
formulas.


title: Phase and frequency noise metrology

abstract:
  As a consequence of a general trend in the physics of oscillators and clocks
towards optics, phase and frequency metrology is rapidly moving to optics too.
Yet, optics is not replacing the traditional radio-frequency (RF) and microwave
domains. Instead, it adds tough challenges. Precision frequency-stability
measurements are chiefly based on the measurement of phase noise, which is the
main focus of this article. Major progress has been achieved in two main areas.
The first is the extreme low-noise measurements, based on the bridge
(interferometric) method in real time or with sophisticated correlation and
averaging techniques. The second is the emerging field of microwave photonics,
which combines optics and RF/microwaves. This includes the femtosecond laser,
the two-way fiber links, the noise measurement systems based on the fiber and
the photonic oscillator. Besides, the phenomenology of flicker (1/f) noise is
better understood, though the ultimate reasons are still elusive.


title:
Universal condition for critical percolation thresholds of kagome-like
  lattices

abstract:
  Lattices that can be represented in a kagome-like form are shown to satisfy a
universal percolation criticality condition, expressed as a relation between
P_3, the probability that all three vertices in the triangle connect, and P_0,
the probability that none connect. A linear approximation for P_3(P_0) is
derived and appears to provide a rigorous upper bound for critical thresholds.
A numerically determined relation for P_3(P_0) gives thresholds for the kagome,
site-bond honeycomb, (3-12^2), and "stack-of-triangle" lattices that compare
favorably with numerical results.


title:
Minimal Faithful Permutation Degrees for Irreducible Coxeter Groups and
  Binary Polyhedral Groups

abstract:
  In this article we calculate the minimal faithful permutation degree for all
of the irreducible Coxeter groups. We also exhibit new examples of finite
groups that possess a quotient whose minimal degree is strictly greater than
that of the group.


title: From Quarks to Strings

abstract:
  In this article, prepared for the book "The birth of string theory", I recall
the sequence of ideas which led to non-critical strings and gauge/strings
duality. I also comment on some promising future directions.


title: Generalized Bunce-Deddens algebras

abstract:
  We define a broad class of crossed product C*-algebras of the form C(G)xG,
where G is a discrete countable amenable residually finite group, and G is a
profinite completion of G. We show that they are unital separable simple
nuclear quasidiagonal C*-algebras, or real rank zero, stable rank one, with
comparability of projections and with a unique trace.


title: Infinite statistics, symmetry breaking and combinatorial hierarchy

abstract:
  The physics of symmetry breaking in theories with strongly interacting quanta
obeying infinite (quantum Boltzmann) statistics known as quons is discussed.
The picture of Bose/Fermi particles as low energy excitations over nontrivial
quon condensate is advocated. Using induced gravity arguments it is
demonstrated that the Planck mass in such low energy effective theory can be
factorially (in number of degrees of freedom) larger than its true ultraviolet
cutoff. Thus, the assumption that statistics of relevant high energy
excitations is neither Bose nor Fermi but infinite can remove the hierarchy
problem without necessity to introduce any artificially large numbers. Quantum
mechanical model illustrating this scenario is presented.


title:
The Cepheid Period-Luminosity Relation (The Leavitt Law) at Mid-Infrared
  Wavelengths: III. Cepheids in NGC 6822

abstract:
  We present the first application of mid-infrared Period-Luminosity relations
to the determination of a Cepheid distance beyond the Magellanic Clouds. Using
archival IRAC imaging data on NGC 6822 from Spitzer we were able to measure
single-epoch magnitudes for sixteen long-period (10 to 100-day) Cepheids at
3.6um, fourteen at 4.5um, ten at 5.8um and four at 8.0um. The measured slopes
and the observed scatter both conform to the relations previously measured for
the Large Magellanic Cloud Cepheids, and fitting to those relations gives
apparent distance moduli of mod{3.6} = 23.57 +/- 0.06, mod{4.5} = 23.55 +/-
0.07, mod{5.8} = 23.60 +/- 0.09 and mod{8.0} = 23.51 +/-0.08 mag. A
multi-wavelength fit to the new IRAC moduli, and previously published BVRIJHK
moduli, allows for a final correction for interstellar reddening and gives a
true distance modulus of 23.49 +/- 0.03 mag with E(B-V) = 0.26 mag,
corresponding to a metric distance of 500 +/-8 kpc.


title:
Nucleon and gamma N -> Delta lattice form factors in a constituent quark
  model

abstract:
  A covariant quark model, based both on the spectator formalism and on vector
meson dominance, and previously calibrated by the physical data, is here
extended to the unphysical region of the lattice data by means of one single
extra adjustable parameter - the constituent quark mass in the chiral limit. We
calculated the Nucleon (N) and the gamma N -> Delta form factors in the
universe of values for that parameter described by quenched lattice QCD. A
qualitative description of the Nucleon and gamma N -> Delta form factors
lattice data is achieved for light pions.


title: On quantum integrability of the Landau-Lifshitz model

abstract:
  We investigate the quantum integrability of the Landau-Lifshitz model and
solve the long-standing problem of finding the local quantum Hamiltonian for
the arbitrary n-particle sector. The particular difficulty of the LL model
quantization, which arises due to the ill-defined operator product, is dealt
with by simultaneously regularizing the operator product, and constructing the
self-adjoint extensions of a very particular structure. The diagonalizibility
difficulties of the Hamiltonian of the LL model, due to the highly singular
nature of the quantum-mechanical Hamiltonian, are also resolved in our method
for the arbitrary n-particle sector. We explicitly demonstrate the consistency
of our construction with the quantum inverse scattering method due to Sklyanin,
and give a prescription to systematically construct the general solution, which
explains and generalizes the puzzling results of Sklyanin for the particular
two-particle sector case. Moreover, we demonstrate the S-matrix factorization
and show that it is a consequence of the discontinuity conditions on the
functions involved in the construction of the self-adjoint extensions.


title:
Reduced free products of unital AH algebras and Blackadar and
  Kirchberg's MF algebras

abstract:
  In the paper, we prove that reduced free products of unital AH algebras with
respect to given faithful tracial states, in the sense of Voiculescu, are
Blackadar and Kirhcberg's MF algebras. We also show that the reduced free
products of unital AH algebras with respect to given faithful tracial states,
under mild conditions, are not quasidiagonal. Therefore we conclude, for a
large class of AH algebras, the Brown-Douglas-Fillmore extension semigroups of
the reduced free products of these AH algebras with respect to given faithful
tracial states are not groups. Our result is based on Haagerup and
Thorbj{\o}rsen's work on the reduced C$^*$-algebras of free groups.


title: Identifying the Potential Biosphere of Mars

abstract:
  Our current knowledge of life on Earth indicates a basic requirement for
liquid water. The locations of present liquid water are therefore the logical
sites to search for current life on Mars. We develop a picture of where on Mars
the regions with the highest potential near-surface liquid water abundance can
be found through a study of gullies. We also use rampart craters to sound the
depth of water ice on Mars and where the highest concentrations of water ice
occur. We estimate that low latitude gullies and rampart craters with depths
greater than 100 m at 30 degrees (absolute) latitude, greater than 1.3 km at 35
degrees and greater than 2.6 km at 40 degrees latitude will give access to
current liquid water environments capable of supporting microbial life. Our
data is most consistent with the formation of these gullies through shallow
aquifer discharge. These features should therefore be high priority targets for
further study and high-resolution imaging with HiRISE.


title:
Calculation of the relative metastabilities of proteins in subcellular
  compartments of Saccharomyces cerevisiae

abstract:
  [abridged] Background: The distribution of chemical species in an open system
at metastable equilibrium can be expressed as a function of environmental
variables which can include temperature, oxidation-reduction potential and
others. Calculations of metastable equilibrium for various model systems were
used to characterize chemical transformations among proteins and groups of
proteins found in different compartments of yeast cells.
  Results: With increasing oxygen fugacity, the relative metastability fields
of model proteins for major subcellular compartments go as mitochondrion,
endoplasmic reticulum, cytoplasm, nucleus. In a metastable equilibrium setting
at relatively high oxygen fugacity, proteins making up actin are predominant,
but those constituting the microtubule occur with a low chemical activity. A
reaction sequence involving the microtubule and spindle pole proteins was
predicted by combining the known intercompartmental interactions with a
hypothetical program of oxygen fugacity changes in the local environment. In
further calculations, the most-abundant proteins within compartments generally
occur in relative abundances that only weakly correspond to a metastable
equilibrium distribution. However, physiological populations of proteins that
form complexes often show an overall positive or negative correlation with the
relative abundances of proteins in metastable assemblages.
  Conclusions: This study explored the outlines of a thermodynamic description
of chemical transformations among interacting proteins in yeast cells. The
results suggest that these methods can be used to measure the degree of
departure of a natural biochemical process or population from a local minimum
in Gibbs energy.


title:
A Simple Performance Analysis of a Core Node in an Optical Burst
  Switched Network

abstract: This paper has been withdrawn


title:
Contention Resolution in Optical Burst Switched Networks using Spectral-
  Amplitude-Coding Optical Code Division Multiple Access

abstract: This paper has been withdrawn by the authors.


title:
Response to arXiv:0811.1802 "Comment on 'Conjectures on exact solution
  of three-dimensional (3D) Ising lattices'" by Perk and Singularities at/near
  infinite temperature: Reply to Perk's Rejoinder arXiv:0901.2935

abstract:
  Part I: The error of eq. (15b) in my article [Z.D. Zhang, Phil. Mag. 87, 5309
(2007), arXiv:0705.1045] in the application of the Jordan-Wigner transformation
does not affect the validity of the putative exact solution, since the solution
is not derived directly from it. Other objections of Perk's Comment
arXiv:0811.1802v2 are the same as those in Wu et al's Comments arXiv:0811.3876
and arXiv:0812.2837, which do not stand on solid ground and have been rejected
in the previous Response arXiv:0812.2330. The conjectured solution can be
utilized to understand critical phenomena in various systems, while the
conjectures are open to prove rigorously. Part II: This is a Reply to Perk's
Rejoinder arXiv:0901.2935. It is shown that the basis of the objections in
Perk's Rejoinder, with respect to singularities at/near infinite temperature,
is based on an error that mixes the concepts of T approaching infinite and T =
infinite. It is shown that the reduced free energy per site f can be used only
for finite temperatures (beta > 0), not for 'exactly' infinite temperature
(beta = 0). At the thermodynamic limit N approaches infinite, besides
infinite-temperature zeros of Z at z = -1 for H = +/- i infinite in the limit
of beta approaching zero, there exists another singularity at z = 1 for the
partition function, which is usually concealed in literature by setting Z to
the power of 1/N and dividing the total free energy F by N (equally,
disregarding the singularity of zeros of 1/Z. The objections in Perk's
Rejoinder are thoroughly disproved.


title: Toric ideals generated by circuits

abstract:
  Let I be the toric ideal of a homogeneous normal configuration. We prove that
I is generated by circuits if and only if each unbalanced circuit of I has a
"connector" which is a linear combination of circuits with a square-free term.
In particular if each circuit of I with non-square-free terms is balanced, then
I is generated by circuits. As a consequence we prove that the toric ideal of a
normal edge subring of a multigraph is generated by circuits with a square-free
term.


title: Some characterizations of affinely full-dimensional factorial designs

abstract:
  A new class of two-level non-regular fractional factorial designs is defined.
We call this class an {\it affinely full-dimensional factorial design}, meaning
that design points in the design of this class are not contained in any affine
hyperplane in the vector space over $\mathbb{F}_2$. The property of the
indicator function for this class is also clarified. A fractional factorial
design in this class has a desirable property that parameters of the main
effect model are simultaneously identifiable. We investigate the property of
this class from the viewpoint of $D$-optimality. In particular, for the
saturated designs, the $D$-optimal design is chosen from this class for the run
sizes $r \equiv 5,6,7$ (mod 8).


title: Zigzag Persistence

abstract:
  We describe a new methodology for studying persistence of topological
features across a family of spaces or point-cloud data sets, called zigzag
persistence. Building on classical results about quiver representations, zigzag
persistence generalises the highly successful theory of persistent homology and
addresses several situations which are not covered by that theory. In this
paper we develop theoretical and algorithmic foundations with a view towards
applications in topological statistics.


title: Convergence to Equilibrium in Local Interaction Games and Ising Models

abstract:
  Coordination games describe social or economic interactions in which the
adoption of a common strategy has a higher payoff. They are classically used to
model the spread of conventions, behaviors, and technologies in societies. Here
we consider a two-strategies coordination game played asynchronously between
the nodes of a network. Agents behave according to a noisy best-response
dynamics.
  It is known that noise removes the degeneracy among equilibria: In the long
run, the ``risk-dominant'' behavior spreads throughout the network. Here we
consider the problem of computing the typical time scale for the spread of this
behavior. In particular, we study its dependence on the network structure and
derive a dichotomy between highly-connected, non-local graphs that show slow
convergence, and poorly connected, low dimensional graphs that show fast
convergence.


title: The effects of flux transport on interface dynamos

abstract:
  The operation of an interface dynamo (as has been suggested for the Sun and
other stars with convective envelopes) relies crucially upon the effective
transport of magnetic flux between two spatially disjoint generation regions.
In the simplest models communication between the two regions is achieved solely
by diffusion. Here we incorporate a highly simplified anisotropic transport
mechanism in order to model the net effect of flux conveyance by magnetic
pumping and by magnetic buoyancy. We investigate the influence of this
mechanism on the efficiency of kinematic dynamo action. It is found that the
effect of flux transport on the efficiency of the dynamo is dependent upon the
spatial profile of the transport. Typically, transport hinders the onset of
dynamo action and increases the frequency of the dynamo waves. However, in
certain cases there exists a preferred magnitude of transport for which dynamo
action is most efficient. Furthermore, we demonstrate the importance of the
imposition of boundary conditions in drawing conclusions on the role of
transport.


title: Spherical Collapse and Cluster Counts in Modified Gravity Models

abstract:
  Modifications to the gravitational potential affect the nonlinear
gravitational evolution of large scale structures in the Universe. To
illustrate some generic features of such changes, we study the evolution of
spherically symmetric perturbations when the modification is of Yukawa type;
this is non-trivial, because we should not and do not assume that Birkhoff's
theorem applies. We then show how to estimate the abundance of virialized
objects in such models. Comparison with numerical simulations shows reasonable
agreement: When normalized to have the same fluctuations at early times, weaker
large scale gravity produces fewer massive halos. However, the opposite can be
true for models that are normalized to have the same linear theory power
spectrum today, so the abundance of rich clusters potentially places
interesting constraints on such models. Our analysis also indicates that the
formation histories and abundances of sufficiently low mass objects are
unchanged from standard gravity. This explains why simulations have found that
the nonlinear power-spectrum at large k is unaffected by such modifications to
the gravitational potential. In addition, the most massive objects in
CMB-normalized models with weaker gravity are expected to be similar to the
high-redshift progenitors of the most massive objects in models with stronger
gravity. Thus, the difference between the cluster and field galaxy populations
is expected to be larger in models with stronger large-scale gravity.


title: A general type of twisted anomaly cancellation formulas

abstract:
  For even dimensional manifolds, we prove some twisted anomaly cancellation
formulas which generalize some well-known cancellation formulas. For odd
dimensional manifolds, we obtain some modularly invariant characteristic forms
by the Chern-Simons transgression and we also get some twisted anomaly
cancellation formulas.


title:
Intermittent Peel Front Dynamics and the Crackling Noise in an Adhesive
  Tape

abstract:
  We report a comprehensive investigation of a model for peeling of an adhesive
tape along with a nonlinear time series analysis of experimental acoustic
emission signals in an effort to understand the origin of intermittent peeling
of an adhesive tape and its connection to acoustic emission. The model
represents the acoustic energy dissipated in terms of Rayleigh dissipation
functional that depends on the local strain rate. We show that the nature of
the peel front exhibits rich spatiotemporal patterns ranging from smooth,
rugged and stuck-peeled configurations that depend on three parameters, namely,
the ratio of inertial time scale of the tape mass to that of the roller, the
dissipation coefficient and the pull velocity. The stuck-peeled configurations
are reminiscent of fibrillar peel front patterns observed in experiments. We
show that while the intermittent peeling is controlled by the peel force
function, the model acoustic energy dissipated depends on the nature of the
peel front and its dynamical evolution. Even though the acoustic energy is a
fully dynamical quantity, it can be quite noisy for a certain set of parameter
values suggesting the deterministic origin of acoustic emission in experiments.
To verify this suggestion, we have carried out a dynamical analysis of
experimental acoustic emission time series for a wide range of traction
velocities. Our analysis shows an unambiguous presence of chaotic dynamics
within a subinterval of pull speeds within the intermittent regime. Time series
analysis of the model acoustic energy signals is also found to be chaotic
within a subinterval of pull speeds.

categories: nlin.CD cond-mat.mtrl-sci cond-mat.stat-mech nlin.PS


title: Universal entanglement entropy in 2D conformal quantum critical points

abstract:
  We study the scaling behavior of the entanglement entropy of two dimensional
conformal quantum critical systems, i.e. systems with scale invariant wave
functions. They include two-dimensional generalized quantum dimer models on
bipartite lattices and quantum loop models, as well as the quantum Lifshitz
model and related gauge theories. We show that, under quite general conditions,
the entanglement entropy of a large and simply connected sub-system of an
infinite system with a smooth boundary has a universal finite contribution, as
well as scale-invariant terms for special geometries. The universal finite
contribution to the entanglement entropy is computable in terms of the
properties of the conformal structure of the wave function of these quantum
critical systems. The calculation of the universal term reduces to a problem in
boundary conformal field theory.


title: Hodge decomposition in the homology of long knots

abstract:
  The paper describes a natural splitting in the rational homology and homotopy
of the spaces of long knots. This decomposition presumably arises from the
cabling maps in the same way as a natural decomposition in the homology of loop
spaces arises from power maps. The generating function for the Euler
characteristics of the terms of this splitting is presented. Based on this
generating function we show that both the homology and homotopy ranks of the
spaces in question grow at least exponentially. Using natural graph-complexes
we show that this splitting on the level of the bialgebra of chord diagrams is
exactly the splitting defined earlier by Dr. Bar-Natan. In the Appendix we
present tables of computer calculations of the Euler characteristics. These
computations give a certain optimism that the Vassiliev invariants of order >
20 can distinguish knots from their inverses.


title:
Shell model study of single-particle and collective structure in
  neutron-rich Cr isotopes

abstract:
  The structure of neutron-rich Cr isotopes is systematically investigated by
using the spherical shell model. The calculations reproduce well the known
energy levels for the even-even $^{52-62}$Cr and odd-mass $^{53-59}$Cr nuclei,
and predict a lowering of excitation energies around neutron number N=40. The
calculated $B(E2;2_{1}^{+}\to 0_{1}^{+})$ systematics shows a pronounced
collectivity around N=40; a similar characteristic behavior has been suggested
for Zn and Ge isotopes. Causes for the sudden drop of the $9/2_{1}^{+}$ energy
in $^{59}$Cr and the appearance of very low $0_{2}^{+}$ states around N=40 are
discussed. We also predict a new band with strong collectivity built on the
$0_{2}^{+}$ state in the N=40 isotope $^{64}$Cr.


title:
Heat transport measurements in turbulent rotating Rayleigh-Benard
  convection

abstract:
  We present experimental heat transport measurements of turbulent
Rayleigh-B\'{e}nard convection with rotation about a vertical axis. The fluid,
water with Prandtl number ($\sigma$) about 6, was confined in a cell which had
a square cross section of 7.3 cm$\times$7.3 cm and a height of 9.4 cm. Heat
transport was measured for Rayleigh numbers $2\times 10^5 <$ Ra $ < 5\times
10^8$ and Taylor numbers $0 <$ Ta $< 5\times 10^{9}$. We show the variation of
normalized heat transport, the Nusselt number, at fixed dimensional rotation
rate $\Omega_D$, at fixed Ra varying Ta, at fixed Ta varying Ra, and at fixed
Rossby number Ro. The scaling of heat transport in the range $10^7$ to about
$10^9$ is roughly 0.29 with a Ro dependent coefficient or equivalently is also
well fit by a combination of power laws of the form $a Ra^{1/5} + b Ra^{1/3}$.
The range of Ra is not sufficient to differentiate single power law or combined
power law scaling. The overall impact of rotation on heat transport in
turbulent convection is assessed.


title:
Entangling photons by means of the nonlinear response of quantum wells
  to an ultrashort pulse

abstract:
  We show that many-body correlations among excitons originating from the Pauli
exclusion principle in a quantum well embedded inside a microcavity provide a
possibility to produce pairs of entangled photons by ultrashort laser pulses
with a yield of $\sim 10^{-2}$. The quantum-field theoretical two-particle
density matrix in second quantization is used to calculate entanglement for
arbitrary emission angles. %At time scales where the heavy-light hole splitting
is resolved the resonances corresponding to different two-exciton %states
develop, which allow for a simple kinematic theory relating the %states of the
outgoing photons with the respective two-exciton states. Largest response can
be expected at symmetric emission angles for resonances with the heavy-heavy
and light-light two-exciton states with remarkably nontrivial dependence of
entanglement on the emission angles and on the ellipticity parameters of the
excitation. We show that the angle dependence can be tailored by means of the
microcavity. Interestingly, the emitted entangled 2-photon states are always in
a triplet state.


title:
International Comparison of Labor Productivity Distribution for
  Manufacturing and Non-Manufacturing Firms

abstract:
  Labor productivity was studied at the microscopic level in terms of
distributions based on individual firm financial data from Japan and the US. A
power-law distribution in terms of firms and sector productivity was found in
both countries' data. The labor productivities were not equal for nation and
sectors, in contrast to the prevailing view in the field of economics. It was
found that the low productivity of the Japanese non-manufacturing sector
reported in macro-economic studies was due to the low productivity of small
firms.


title: Optimal Tracking of Distributed Heavy Hitters and Quantiles

abstract:
  We consider the the problem of tracking heavy hitters and quantiles in the
distributed streaming model. The heavy hitters and quantiles are two important
statistics for characterizing a data distribution. Let $A$ be a multiset of
elements, drawn from the universe $U=\{1,...,u\}$. For a given $0 \le \phi \le
1$, the $\phi$-heavy hitters are those elements of $A$ whose frequency in $A$
is at least $\phi |A|$; the $\phi$-quantile of $A$ is an element $x$ of $U$
such that at most $\phi|A|$ elements of $A$ are smaller than $A$ and at most
$(1-\phi)|A|$ elements of $A$ are greater than $x$. Suppose the elements of $A$
are received at $k$ remote {\em sites} over time, and each of the sites has a
two-way communication channel to a designated {\em coordinator}, whose goal is
to track the set of $\phi$-heavy hitters and the $\phi$-quantile of $A$
approximately at all times with minimum communication. We give tracking
algorithms with worst-case communication cost $O(k/\eps \cdot \log n)$ for both
problems, where $n$ is the total number of items in $A$, and $\eps$ is the
approximation error. This substantially improves upon the previous known
algorithms. We also give matching lower bounds on the communication costs for
both problems, showing that our algorithms are optimal. We also consider a more
general version of the problem where we simultaneously track the
$\phi$-quantiles for all $0 \le \phi \le 1$.


title: On determinism and well-posedness in multiple time dimensions

abstract:
  We study the initial value problem for the wave equation and the
ultrahyperbolic equation for data posed on initial surface of mixed signature
(both spacelike and timelike). Under a nonlocal constraint, we show that the
Cauchy problem on codimension-one hypersurfaces has global unique solutions in
the Sobolev spaces $H^{m}$, thus it is well-posed. In contrast, we show that
the initial value problem on higher codimension hypersurfaces is ill-posed, at
least when specifying a finite number of derivatives of the data, due to the
failure of uniqueness. This is in contrast to a uniqueness result which Courant
and Hilbert deduce from Asgeirsson's mean value theorem, for which we give an
independent derivation. The proofs use Fourier synthesis and the Holmgren-John
uniqueness theorem.


title:
Localization in Correlated Bi-Layer Structures: From Photonic Cristals
  to Metamaterials and Electron Superlattices

abstract:
  In a unified approach, we study the transport properties of
periodic-on-average bi-layered photonic crystals, metamaterials and electron
superlattices. Our consideration is based on the analytical expression for the
localization length derived for the case of weakly fluctuating widths of
layers, that also takes into account possible correlations in disorder. We
analyze how the correlations lead to anomalous properties of transport. In
particular, we show that for quarter stack layered media specific correlations
can result in a $\omega^2$-dependence of the Lyapunov exponent in all spectral
bands.


title: Quantum of area from gravitation on complex octonions

abstract:
  Using spin 1/2 particle elastic scattering on a fixed target, in a 1/|x|
potential on Euclidean metric, a minimum scattering cross section appears from
the spin contribution. Interpreted as semi-classical limit of an earlier
proposed operator formulation of four dimensional Euclidean quantum gravity,
using non-associative complex octonion algebra, this is understood as an area
quantum for the observation: Existence of finite (quantized) charges yields a
minimum area element of interaction. This suggests that models built on the
fundamental assumption of a quantized area element (namely as in Loop Quantum
Gravity) may in principle approximate General Relativity in the non-quantum
limit.


title: Local aspects of free open bosonic string field theory

abstract:
  We show that strictly local observables with arbitrarily small support in
space-time exist in covariant free open bosonic string field theory. The main
ingredient of the proof is a modified version of the well known DDF operators,
which we rigourously define. This result allows in principle the definition of
a net of local observable algebras and should be considered as a first step
towards the application of algebraic quantum field theory to this case


title: An Analytic Approach to Stability

abstract:
  The stability method is very useful for obtaining exact solutions of many
extremal graph problems. Its key step is to establish the stability property
which, roughly speaking, states that any two almost optimal graphs of the same
order $n$ can be made isomorphic by changing o(n^2) edges.
  Here we show how the recently developed theory of graph limits can be used to
give an analytic approach to stability. As an application, we present a new
proof of the Erdos-Simonovits Stability Theorem.
  Also, we investigate various properties of the edit distance. In particular,
we show that the combinatorial and fractional versions are within a constant
factor from each other, thus answering a question of Goldreich, Krivelevich,
Newman, and Rozenberg.


title: Face vectors of two-dimensional Buchsbaum complexes

abstract:
  In this paper, we characterize all possible h-vectors of 2-dimensional
Buchsbaum simplicial complexes.


title:
Study of phase stability of MnCr using the augmented space recursion
  based orbital peeling technique

abstract:
  In an earlier communication we have developed a recursion based approach to
the study of phase stability and transition of binary alloys. We had combined
the recursion method introduced by Haydock, Heine and Kelly and the our
augmented space approach with the orbital peeling technique proposed by Burke
to determine the small energy differences involved in the discussion of phase
stability. We extend that methodology for the study of MnCr alloys.


title:
On bi-hamiltonian geometry of some integrable systems on the sphere with
  cubic integral of motion

abstract:
  We obtain bi-Hamiltonian structure for a family of integrable systems on the
sphere S with an additional integral of third order in momenta. These results
are applied to the Goryachev system and Goryachev-Chaplygin top for which we
give an explicit procedure to find the separated coordinates and the separated
relations.


title:
Quantum trajectory equation for multiple qubits in circuit QED:
  Generating entanglement by measurement

abstract:
  In this paper we derive an effective master equation and quantum trajectory
equation for multiple qubits in a single resonator and in the large resonator
decay limit. We show that homodyne measurement of the resonator transmission is
a weak measurement of the collective qubit inversion. As an example of this
result, we focus on the case of two qubits and show how this measurement can be
used to generate an entangled state from an initially separable state. This is
realized without relying on an entangling Hamiltonian. We show that, for {\em
current} experimental values of both the decoherence and measurement rates,
this approach can be used to generate highly entangled states. This scheme
takes advantage of the fact that one of the Bell states is decoherence-free
under Purcell decay.


title:
Neutrino Signals from Annihilating/Decaying Dark Matter in the Light of
  Recent Measurements of Cosmic Ray Electron/Positron Fluxes

abstract:
  The excess of cosmic-ray electron and positron fluxes measured by the PAMELA
satellite and ATIC balloon experiments may be interpreted as the signals of the
dark matter annihilation or decay into leptons. In this letter we show that the
dark matter annihilation/decay which reproduces the electron/positron excess
may yield a significant amount of high-energy neutrinos from the Galactic
center. In the case, future kilometer-square size experiments may confirm such
a scenario, or even the Super-Kamiokande results already put constraints on
some dark matter models.


title: Qubit dispersive readout scheme with a microstrip squid amplifier

abstract:
  A flux qubit readout scheme involving a dispersive technique coupled to a
microstrip squid amplifier has been tested experimentally. Thanks to the almost
quantum limited noise of this amplifier at low temperature, this readout device
is very promising for a design with actual qubits. It's proof of principle and
low noise performance have been tested by simulating the qubit presence
applying a tiny flux change in the input squid. The resonant frequency of the
amplifier is adjusted in-situ with a varactor diode to approach the frequency
of the tank circuit. Depending on the sign of the transfer function, two
operating mode (crossing or anticrossing regime) have been identified.


title:
Singular Hermitian-Einstein monopoles on the product of a circle and a
  Riemann surface

abstract:
  In this paper, the moduli space of singular unitary Hermitian--Einstein
monopoles on the product of a circle and a Riemann surface is shown to
correspond to a moduli space of stable pairs on the Riemann surface. These
pairs consist of a holomorphic vector bundle on the surface and a meromorphic
automorphism of the bundle. The singularities of this automorphism correspond
to the singularities of the singular monopole. We then consider the complex
geometry of the moduli space; in particular, we compute dimensions, both from
the complex geometric and the gauge theoretic point of view.


title:
Cryogenic spectroscopy of ultra-low density colloidal lead chalcogenide
  quantum dots on chip-scale optical cavities towards single quantum dot
  near-infrared cavity QED

abstract:
  We present evidence of cavity quantum electrodynamics from a sparse density
of strongly quantum-confined Pb-chalcogenide nanocrystals (between 1 and 10)
approaching single-dot levels on moderately high-Q mesoscopic silicon optical
cavities. Operating at important near-infrared (1500-nm) wavelengths, large
enhancements are observed from devices and strong modifications of the QD
emission are achieved. Saturation spectroscopy of coupled QDs is observed at
77K, highlighting the modified nanocrystal dynamics for quantum information
processing.