title: Dynamic modeling of mean-reverting spreads for statistical arbitrage

abstract:
  Statistical arbitrage strategies, such as pairs trading and its
generalizations, rely on the construction of mean-reverting spreads enjoying a
certain degree of predictability. Gaussian linear state-space processes have
recently been proposed as a model for such spreads under the assumption that
the observed process is a noisy realization of some hidden states. Real-time
estimation of the unobserved spread process can reveal temporary market
inefficiencies which can then be exploited to generate excess returns. Building
on previous work, we embrace the state-space framework for modeling spread
processes and extend this methodology along three different directions. First,
we introduce time-dependency in the model parameters, which allows for quick
adaptation to changes in the data generating process. Second, we provide an
on-line estimation algorithm that can be constantly run in real-time. Being
computationally fast, the algorithm is particularly suitable for building
aggressive trading strategies based on high-frequency data and may be used as a
monitoring device for mean-reversion. Finally, our framework naturally provides
informative uncertainty measures of all the estimated parameters. Experimental
results based on Monte Carlo simulations and historical equity data are
discussed, including a co-integration relationship involving two
exchange-traded funds.


title: Analytic continuation in mapping spaces

abstract:
  We consider a Stein manifold $M$ of dimension $\geq 2$ and a compact subset
$K\subset M$ such that $M'=M\backslash K$ is connected. Let $S$ be a compact
differential manifold, and let $M_S$, resp. $M'_S$ stand for the complex
manifold of maps $S\to M$, resp. $S\to M'$, of some specified regularity, that
are homotopic to constant. We prove that any holomorphic function on $M'_S$
continues analytically to $M_S$ (perhaps as a multivalued function).


title: Electrical Control of Exchange Bias Mediated by Graphene

abstract:
  The role of graphene in mediating the exchange interaction is theoretically
investigated when it is placed between two ferromagnetic dielectric materials.
The calculation based on a tight-binding model illustrates that the magnetic
interactions at the interfaces affect not only the graphene band structure but
also the thermodynamic potential of the system. This induces an indirect
exchange interaction between the magnetic layers that can be considered in term
of an effective exchange bias field. The analysis clearly indicates a strong
dependence of the effective exchange bias on the properties of the mediating
layer, revealing an effective mechanism of electrical control even at room
temperature. This dependence also results in qualitatively different
characteristics for the cases involving mono- and bilayer graphene.


title: Loose Hamilton cycles in hypergraphs

abstract:
  We prove that any k-uniform hypergraph on n vertices with minimum degree at
least n/(2(k-1))+o(n) contains a loose Hamilton cycle. The proof strategy is
similar to that used by K\"uhn and Osthus for the 3-uniform case. Though some
additional difficulties arise in the k-uniform case, our argument here is
considerably simplified by applying the recent hypergraph blow-up lemma of
Keevash.


title: On the G_2 bundle of a Riemannian 4-manifold

abstract:
  We study the natural G_2 structure on the unit tangent sphere bundle SM of
any given orientable Riemannian 4-manifold M, as it was discovered in
\cite{AlbSal}. A name is proposed for the space. We work in the context of
metric connections, or so called geometry with torsion, and describe the
components of the torsion of the connection which imply certain equations of
the G_2 structure. This article is devoted to finding the G_2-torsion tensors
which classify our structure according to the theory in \cite{FerGray}.


title:
Curvature effect on the interaction between folded graphitic surface and
  silver clusters

abstract:
  Evidence of curvature effects on the interaction and binding of silver
clusters on folded graphitic surfaces has been shown from both experiment and
theory. Density Functional Theory (DFT) calculations within the local density
and generalized gradient approximations have been performed for the structural
relaxation of both Ag and Ag$_2$ on curved surfaces, showing a cross-over from
quantum to classical behaviour. Using Lennard-Jones potential to model the
interaction between a single cluster and the graphene surface, evidence is
found for the curvature effect on the binding of silver nano-particles to
folding graphitic surfaces. The theoretical results are compared to SEM and AFM
images of samples obtained from pre-formed silver cluster deposition on
carboneous substrates exhibiting anisotropic pleat structures.


title: Rapidly Rotating Suns and Active Nests of Convection

abstract:
  In the solar convection zone, rotation couples with intensely turbulent
convection to drive a strong differential rotation and achieve complex magnetic
dynamo action. Our sun must have rotated more rapidly in its past, as is
suggested by observations of many rapidly rotating young solar-type stars. Here
we explore the effects of more rapid rotation on the global-scale patterns of
convection in such stars and the flows of differential rotation and meridional
circulation which are self-consistently established. The convection in these
systems is richly time dependent and in our most rapidly rotating suns a
striking pattern of localized convection emerges. Convection near the equator
in these systems is dominated by one or two nests in longitude of locally
enhanced convection, with quiescent streaming flow in between at the highest
rotation rates. These active nests of convection maintain a strong differential
rotation despite their small size. The structure of differential rotation is
similar in all of our more rapidly rotating suns, with fast equators and slower
poles. We find that the total shear in differential rotation Delta Omega grows
with more rapid rotation while the relative shear Delta Omega/Omega_0
decreases. In contrast, at more rapid rotation the meridional circulations
decrease in energy and peak velocities and break into multiple cells of
circulation in both radius and latitude.


title: Coherent sheaves and cohesive sheaves

abstract:
  We consider coherent and cohesive sheaves of $\cO$--modules over open sets
$\Omega\subset\bC^n$. We prove that coherent sheaves, and certain other sheaves
derived from them, are cohesive; and conversely, certain sheaves derived from
cohesive sheaves are coherent. An important tool in all this, also proved here,
is that the sheaf of Banach space valued holomorphic germs is flat.


title:
Measurements of cosmic-ray secondary nuclei at high energies with the
  first flight of the CREAM balloon-borne experiment

abstract:
  We present new measurements of heavy cosmic-ray nuclei at high energies per-
formed during the first flight of the balloon-borne cosmic-ray experiment CREAM
(Cosmic-Ray Energetics And Mass). This instrument uses multiple charge
detectors and a transition radiation detector to provide the first high
accuracy measurements of the relative abundances of elements from boron to
oxygen up to energies around 1 TeV/n. The data agree with previous measurements
at lower energies and show a relatively steep decline (~E$^-0.6$ to E$^-0.5$)
at high energies. They further show the source abundance of nitrogen relative
to oxygen is ~10% in the TeV/n region.


title: A Probable New Globular Cluster in the Galactic Disk

abstract:
  We report the discovery of a probable new globular cluster in the disk of the
Milky Way. Visible in 2MASS and the GLIMPSE survey, it has an estimated
foreground extinction of A_V ~ 24 mag. The absolute magnitude of the cluster
and the luminosity function of the red giant branch are most consistent with
that of an old globular cluster with a mass of a few times 10^5 solar masses at
a distance of 4-8 kpc.


title:
Recursion Relations, Generating Functions, and Unitarity Sums in N=4 SYM
  Theory

abstract:
  We prove that the MHV vertex expansion is valid for any NMHV tree amplitude
of N=4 SYM. The proof uses induction to show that there always exists a complex
deformation of three external momenta such that the amplitude falls off at
least as fast as 1/z for large z. This validates the generating function for
n-point NMHV tree amplitudes. We also develop generating functions for anti-MHV
and anti-NMHV amplitudes. As an application, we use these generating functions
to evaluate several examples of intermediate state sums on unitarity cuts of
1-, 2-, 3- and 4-loop amplitudes. In a separate analysis, we extend the recent
results of arXiv:0808.0504 to prove that there exists a valid 2-line shift for
any n-point tree amplitude of N=4 SYM. This implies that there is a BCFW
recursion relation for any tree amplitude of the theory.


title:
Initial Results on the F-logic to OWL Bi-directional Translation on a
  Tabled Prolog Engine

abstract:
  In this paper, we show our results on the bi-directional data exchange
between the F-logic language supported by the Flora2 system and the OWL
language. Most of the TBox and ABox axioms are translated preserving the
semantics between the two representations, such as: proper inclusion,
individual definition, functional properties, while some axioms and
restrictions require a change in the semantics, such as: numbered and qualified
cardinality restrictions. For the second case, we translate the OWL definite
style inference rules into F-logic style constraints. We also describe a set of
reasoning examples using the above translation, including the reasoning in
Flora2 of a variety of ABox queries.


title: Broadband Radiation from Primary Electrons in Very Energetic Supernovae

abstract:
  A class of very energetic supernovae (hypernovae) is associated with long
gamma-ray bursts, in particular with a less energetic but more frequent
population of gamma-ray bursts. Hypernovae also appear to be associated with
mildly relativistic jets or outflows, even in the absence of gamma-ray bursts.
Here we consider radiation from charged particles accelerated in such mildly
relativistic outflows with kinetic energies of ~10^{50} erg. The radiation
processes of the primarily accelerated electrons considered are synchrotron
radiation and inverse-Compton scattering of synchrotron photons (synchrotron
self-Compton; SSC) and of supernova photons (external inverse-Compton; EIC). In
the soft X-ray regime, both the SSC and EIC flux can be the dominant component,
but due to their very different spectral shapes it should be easy to
distinguish between them. When the fraction of the kinetic energy going into
the electrons (\epsilon_e) is large, the SSC is expected to be important;
otherwise the EIC will dominate. The EIC flux is quite high, almost
independently of \epsilon_e, providing a good target for X-ray telescopes such
as XMM-Newton and Chandra. In the GeV gamma-ray regime, the EIC would be the
dominant radiation process and the Gamma-ray Large Area Space Telescope (GLAST)
should be able to probe the value of \epsilon_e, the spectrum of the electrons,
and their maximum acceleration energy. Accelerated protons also lead to photon
radiation through the secondary electrons produced by the photopion and
photopair processes. We find that over a significant range of parameters the
proton component is generally less prominent than the primary electron
component. We discuss the prospects for the detection of the X-ray and GeV
signatures of the mildly relativistic outflow of hypernovae.


title: Corner Junction as a Probe of Helical Edge States

abstract:
  We propose and analyze inter-edge tunneling in a quantum spin Hall corner
junction as a means to probe the helical nature of the edge states. We show
that electron-electron interactions in the one-dimensional helical edge states
result in Luttinger parameters for spin and charge that are intertwined, and
thus rather different than those for a quantum wire with spin rotation
invariance. Consequently, we find that the four-terminal conductance in a
corner junction has a distinctive form that could be used as evidence for the
helical nature of the edge states.


title: Non-linear Redshift-Space Power Spectra

abstract:
  Distances in cosmology are usually inferred from observed redshifts - an
estimate that is dependent on the local peculiar motion - giving a distorted
view of the three dimensional structure and affecting basic observables such as
the correlation function and power spectrum. We calculate the full non-linear
redshift-space power spectrum for Gaussian fields, giving results for both the
standard flat sky approximation and the directly-observable angular correlation
function and angular power spectrum. Coupling between large and small scale
modes boosts the power on small scales when the perturbations are small. On
larger scales power is slightly suppressed by the velocities perturbations on
smaller scales. The analysis is general, but we comment specifically on the
implications for future high-redshift observations, and show that the
non-linear spectrum has significantly more complicated angular structure than
in linear theory. We comment on the implications for using the angular
structure to separate cosmological and astrophysical components of 21 cm
observations.


title: Gravity Duals of Lifshitz-like Fixed Points

abstract:
  We find candidate macroscopic gravity duals for scale-invariant but
non-Lorentz invariant fixed points, which do not have particle number as a
conserved quantity. We compute two-point correlation functions which exhibit
novel behavior relative to their AdS counterparts, and find holographic
renormalization group flows to conformal field theories. Our theories are
characterized by a dynamical critical exponent $z$, which governs the
anisotropy between spatial and temporal scaling $t \to \lambda^z t$, $x \to
\lambda x$; we focus on the case with $z=2$. Such theories describe
multicritical points in certain magnetic materials and liquid crystals, and
have been shown to arise at quantum critical points in toy models of the
cuprate superconductors. This work can be considered a small step towards
making useful dual descriptions of such critical points.


title:
X-Ray Emission from a Supermassive Black Hole Ejected from the Center of
  a Galaxy

abstract:
  Recent studies have indicated that the emission of gravitational waves at the
merger of two black holes gives a kick to the final black hole. If the
supermassive black hole at the center of a disk galaxy is kicked but the
velocity is not large enough to escape from the host galaxy, it will fall back
onto the the disk and accrete the interstellar medium in the disk. We study the
X-ray emission from the black holes with masses of ~10^7 M_sun recoiled from
the galactic center with velocities of ~600 km s^-1. We find that their
luminosities can reach ~>10^39 erg s^-1, when they pass the apastrons in the
disk. While the X-ray luminosities are comparable to those of ultra-luminous
X-ray sources (ULXs) observed in disk galaxies, ULXs observed so far do not
seem to be such supermassive black holes. Statical studies could constrain the
probability of merger and recoil of supermassive black holes.


title:
Mapping the Dark Matter From UV Light at High Redshift: An Empirical
  Approach to Understand Galaxy Statistics

abstract:
  We present a simple formalism to interpret two galaxy statistics, the UV
luminosity function and two-point correlation functions for star-forming
galaxies at z~4, 5, 6 in the context of LCDM cosmology. Both statistics are the
result of how star formation takes place in DM halos, and thus are used to
constrain how UV light depends on halo properties such as mass. The two
measures were taken from the GOODS data, thus ideal for joint analysis. The two
physical quantities we explore are the SF duty cycle, and the range of L_UV
that a halo of mass M can have (mean and variance). The former addresses the
typical duration of SF activity in halos while the latter addresses the
averaged SF history and regularity of gas inflow into these systems. We explore
various physical models consistent with data, and find the following: 1) the
typical duration of SF observed in the data is <0.4 Gyr (1 sig), 2) the
inferred scaling law between L_UV and halo mass M from the observed slope of
the LFs is roughly linear at all redshifts, and 3) L_UV for a fixed halo mass
decreases with time, implying that the SF efficiency (after dust extinction) is
higher at earlier times. We explore several physical scenarios relating star
formation to halo mass, but find that these scenarios are indistinguishable due
to the limited range of halo mass probed by our data. In order to discriminate
between different scenarios, we discuss constraining the bright-faint galaxy
cross-correlation functions and luminosity-dependence of galaxy bias.
(Abridged)


title:
A Tale of Two Herbig Ae stars -MWC275 and AB Aurigae: Comprehensive
  Models for SED and Interferometry

abstract:
  We present comprehensive models for the Herbig Ae stars MWC275 and AB Aur
that aim to explain their spectral energy distribution (from UV to millimeter)
and long baseline interferometry (from near-infrared to millimeter)
simultaneously. Data from the literature, combined with new mid-infrared (MIR)
interferometry from the Keck Segment Tilting Experiment, are modeled using an
axisymmetric Monte Carlo radiative transfer code. Models in which most of the
near-infrared (NIR) emission arises from a dust rim fail to fit the NIR
spectral energy distribution (SED) and sub-milli-arcsecond NIR CHARA
interferometry. Following recent work, we include an additional gas emission
component with similar size scale to the dust rim, inside the sublimation
radius, to fit the NIR SED and long-baseline NIR interferometry on MWC275 and
AB Aur. In the absence of shielding of star light by gas, we show that the
gas-dust transition region in these YSOs will have to contain highly refractory
dust, sublimating at ~1850K. Despite having nearly identical structure in the
thermal NIR, the outer disks of MWC275 and AB Aur differ substantially. In
contrast to the AB Aur disk, MWC275 lacks small grains in the disk atmosphere
capable of producing significant 10-20micron emission beyond ~7AU, forcing the
outer regions into the "shadow" of the inner disk


title: Dark Scalar Doublets and Neutrino Tribimaximal Mixing from A_4 Symmetry

abstract:
  In the context of A_4 symmetry, neutrino tribimaximal mixing is achieved
through the breaking of A_4 to Z_3 (Z_2) in the charged-lepton (neutrino)
sector respectively. The implied vacuum misalignment of the (1,1,1) and (1,0,0)
directions in A_4 space is a difficult technical problem, and cannot be treated
without many auxiliary fields and symmetries (and perhaps extra dimensions). It
is pointed out here that an alternative scenario exists with A_4 alone and no
redundant fields, if neutrino masses are "scotogenic", i.e. radiatively induced
by dark scalar doublets as recently proposed.


title:
Unambiguous modification of nonorthogonal single and two photon
  polarization states

abstract:
  In this work we propose a probabilistic method which allows an unambiguous
modification of two non-orthogonal quantum states. We experimentally implement
this protocol by using two-photon polarization states generated in the process
of spontaneous parametric down conversion. In the experiment, for codifying
initial quantum states, we consider single photon states and heralded
detection. We show that the application of this protocol to entangled states,
it allows a fine control of the amount of entanglement of the initial state.


title:
Generalized Polar Decompositions for Closed Operators in Hilbert Spaces
  and Some Applications

abstract:
  We study generalized polar decompositions of densely defined, closed linear
operators in Hilbert spaces and provide some applications to relatively (form)
bounded and relatively (form) compact perturbations of self-adjoint, normal,
and m-sectorial operators.


title: Pattern formation in growing sandpiles

abstract:
  Adding grains at a single site on a flat substrate in the Abelian sandpile
models produce beautiful complex patterns. We study in detail the pattern
produced by adding grains on a two-dimensional square lattice with directed
edges (each site has two arrows directed inward and two outward), starting with
a periodic background with half the sites occupied. The size of the pattern
formed scales with the number of grains added $N$ as $\sqrt{N}$. We give exact
characterization of the asymptotic pattern, in terms of the position and shape
of different features of the pattern.


title:
Magnetism Driven by Anion Vacancies in Superconducting
  $\alpha$--FeSe$_{1-x}$

abstract:
  To study the microscopic electronic and magnetic interactions in the
substoichiometric iron chalcogenide FeSe$_{1-x}$ which is observed to
superconduct at x~1/8 up to $T_c$=27 K, we use first principles methods to
study the Se vacancy in this nearly magnetic FeSe system. The vacancy forms a
ferrimagnetic cluster of eight Fe atoms, which for the ordered x=1/8 alloy
leads to half metallic conduction. Similar magnetic clusters are obtained for
FeTe$_{1-x}$ and for BaFe$_2$As$_2$ with an As vacancy, although neither of
these are half metallic. Based on fixed spin density results, we suggest the
low energy excitations in FeSe$_{1-x}$ are antiparamagnon-like with short
correlation length.


title: Observation of a continuous phase transition in a shape-memory alloy

abstract:
  Elastic neutron-scattering, inelastic x-ray scattering, specific-heat, and
pressure-dependent electrical transport measurements have been made on single
crystals of AuZn and Au_{0.52}Zn_{0.48} above and below their martensitic
transition temperatures (T_M=64K and 45K, respectively). In each composition,
elastic neutron scattering detects new commensurate Bragg peaks (modulation)
appearing at Q = (1.33,0.67,0) at temperatures corresponding to each sample's
T_M. Although the new Bragg peaks appear in a discontinuous manner in the
Au_{0.52}Zn_{0.48} sample, they appear in a continuous manner in AuZn.
Surprising us, the temperature dependence of the AuZn Bragg peak intensity and
the specific-heat jump near the transition temperature are in favorable accord
with a mean-field approximation. A Landau-theory-based fit to the pressure
dependence of the transition temperature suggests the presence of a critical
endpoint in the AuZn phase diagram located at T_M*=2.7K and p*=3.1GPa, with a
quantum saturation temperature \theta_s=48.3 +/- 3.7K.


title:
Hawking radiation via Anomaly and Tunneling method from Unruh's and
  Canonical acoustic black hole

abstract:
  Hawking radiation from Unruh's and Canonical acoustic black hole is
considered from viewpoint of anomaly cancellation method developed by Robinson
and Wilczek. Thus, the physics near the horizon can be described using an
infinite collection of massless two-dimensional scalar fields in the background
of a dilaton and the gravitational anomaly is canceled by the flux of a 1 + 1
dimensional blackbody at the Hawking temperature of the space-time.
Consequently, by this method, we can get the Hawking's temperature for
Canonical and Unruh's acoustic black hole.


title: Trapping in complex networks

abstract:
  We investigate the trapping problem in Erdos-Renyi (ER) and Scale-Free (SF)
networks. We calculate the evolution of the particle density $\rho(t)$ of
random walkers in the presence of one or multiple traps with concentration $c$.
We show using theory and simulations that in ER networks, while for short times
$\rho(t) \propto \exp(-Act)$, for longer times $\rho(t)$ exhibits a more
complex behavior, with explicit dependence on both the number of traps and the
size of the network. In SF networks we reveal the significant impact of the
trap's location: $\rho(t)$ is drastically different when a trap is placed on a
random node compared to the case of the trap being on the node with the maximum
connectivity. For the latter case we find
$\rho(t)\propto\exp\left[-At/N^\frac{\gamma-2}{\gamma-1}\av{k}\right]$ for all
$\gamma>2$, where $\gamma$ is the exponent of the degree distribution
$P(k)\propto k^{-\gamma}$.


title:
The Properties of Long-Period Variables in the Large Magellanic Cloud
  from MACHO

abstract:
  We present a new analysis of the long-period variables in the Large
Magellanic Cloud (LMC) from the MACHO Variable Star Catalog. Three-quarters of
our sample of evolved, variable stars have periodic light curves. We
characterize the stars in our sample using the multiple periods found in their
frequency spectra. Additionally, we use single-epoch Two Micron All Sky Survey
measurements to construct the average infrared light curves for different
groups of these stars. Comparison with evolutionary models shows that stars on
the red giant branch (RGB) or the early asymptotic giant branch (AGB) often
show non-periodic variability, but begin to pulsate with periods on the two
shortest period-luminosity sequences (3 & 4) when they brighten to K_s ~ 13.
The stars on the thermally pulsing AGB are more likely to pulsate with longer
periods that lie on the next two P-L sequences (1 & 2), including the sequence
associated with the Miras in the LMC. The Petersen diagram and its variants
show that multi-periodic stars on each pair of these sequences (3 & 4, and 1 &
2) typically pulsate with periods associated only with that pair. The periods
in these multi-periodic stars become longer and stronger as the star evolves.
We further constrain the mechanism behind the long secondary periods (LSPs)
seen in half of our sample, and find that there is a close match between the
luminosity functions of the LSP stars and all of the stars in our sample, and
that these star's pulsation amplitudes are relatively wavelength independent.
Although this is characteristic of stellar multiplicity, the large number of
these variables is problematic for that explanation.


title: Mapping low-latitude stellar substructure with SEGUE photometry

abstract:
  Encircling the Milky Way at low latitudes, the Low Latitude Stream is a large
stellar structure, the origin of which is as yet unknown. As part of the SEGUE
survey, several photometric scans have been obtained that cross the Galactic
plane, spread over a longitude range of 50 to 203 degrees. These data allow a
systematic study of the structure of the Galaxy at low latitudes, where the Low
Latitude Stream resides. We apply colour-magnitude diagram fitting techniques
to map the stellar (sub)structure in these regions, enabling the detection of
overdensities with respect to smooth models. These detections can be used to
distinguish between different models of the Low Latitude Stream, and help to
shed light on the nature of the system.


title: Critical Charges on Strange Quark Nuggets and Other Extended Objects

abstract:
  We investigate the behavior of the critical charge for spontaneous pair
production, $Z_C$, defined as the charge at which the total energy of a
$K$-shell electron is $E=-m_e$, as a function of the radius $R$ of the charge
distribution. Our approach is to solve the Dirac equation for a potential
$V(r)$ consisting of a spherically symmetrical charge distribution of radius
$R$ and a Coulomb tail. For a spherical shell distribution of the type usually
associated with color-flavor locked strange quark nuggets, we confirm the
relation $Z_C=0.71 R({\rm fm})$ for sufficiently large $R$ obtained by Madsen,
who used an approach based on the Thomas-Fermi model. We also present results
for a uniformly charged sphere and again find that $Z_C\sim R$ for large enough
$R$. Also discussed is the behavior of $Z_C$ when simple {\it ad hoc}
modifications are made to the potential for $0\leq r < R$.


title: Gamma-Ray Emission from the Broad-Line Radio Galaxy 3C111

abstract:
  The broad-line radio galaxy 3C111 has been suggested as the counterpart of
the gamma-ray source 3EGJ0416+3650. While 3C111 meets most of the criteria for
a high-probability identification, like a bright flat-spectrum radio core and a
blazar-like broadband SED, in the Third EGRET Catalog, the large positional
offset of about 1.5 degrees put 3C111 outside the 99% probability region for
3EGJ0416+3650, making this association questionable. We present a re-analysis
of all available data for 3C111 from the EGRET archives, resulting in probable
detection of high-energy gamma-ray emission above 1000MeV from a position close
to the nominal position of 3C111, in two separate viewing periods (VPs), at a
3-sigma level in each. A new source, GROJ0426+3747, appears to be present
nearby. For >100MeV, one source seems to account for most of the EGRET-detected
emission of 3EGJ0416+3650. A follow-up Swift UVOT/XRT observation reveals one
moderately bright X-ray source in the error box of 3EGJ0416+3650, but because
of the large EGRET position uncertainty, it is not certain that the X-ray and
gamma-ray sources are associated. Another Swift observation, of GROJ0426+3747,
detected no X-ray source nearby.


title: D-bar Spark Theory and Deligne Cohomology

abstract:
  We study the Harvey-Lawson spark characters of level p on complex manifolds.
Presenting Deligne cohomology classes by sparks of level $p$, we give an
explicit analytic product formula for Deligne cohomology. We also define
refined Chern classes in Deligne cohomology for holomorphic vector bundles over
complex manifolds. Applications to algebraic cycles are given. A Bott-type
vanishing theorem in Deligne cohomology for holomorphic foliations is
established. A general construction of Nadel-type invariants is given together
with a new proof of Nadel's conjecture.


title:
Weakly turbulent solutions for the cubic defocusing nonlinear
  Schr\"odinger equation

abstract:
  We consider the cubic defocusing nonlinear Schr\"odinger equation on the two
dimensional torus. We exhibit smooth solutions for which the support of the
conserved energy moves to higher Fourier modes. This weakly turbulent behavior
is quantified by the growth of higher Sobolev norms: given any delta << 1, K
>>1, s >1, we construct smooth initial data u_0 with ||u_0||_{{H}^s} < delta,
so that the corresponding time evolution u satisfies ||u(T)||_{{H}^s} > K at
some time T. This growth occurs despite the Hamiltonian's bound on
||u(t)||_{\dot{H}^1} and despite the conservation of the quantity
||u(t)||_{L^2}.
  The proof contains two arguments which may be of interest beyond the
particular result described above. The first is a construction of the
solution's frequency support that simplifies the system of ODE's describing
each Fourier mode's evolution. The second is a construction of solutions to
these simpler systems of ODE's which begin near one invariant manifold and
ricochet from arbitrarily small neighborhoods of an arbitrarily large number of
other invariant manifolds. The techniques used here are related to but are
distinct from those traditionally used to prove Arnold Diffusion in
perturbations of Hamiltonian systems.


title: Central Simple Algebras with Involution: A Geometric Approach

abstract:
  Let $k$ be an algebraically closed base field of characteristic zero. The
category equivalence between central simple algebras and irreducible,
generically free $PGL_n$-varieties is extended to the context of central simple
algebras with involution. The associated variety of a central simple algebra
with involution comes with an action of the semidirect product
$P_{n,\tau}:=PGL_n\rtimes<\tau>$, where $\tau$ is the automorphism of $\PGLn$
given by $\tau(h)=(h^{-1})^transpose$. Basic properties of an involution are
described in terms of the action of $P_{n,\tau}$ on the associated variety, and
in particular in terms of the stabilizer in general position for this action.


title: Our Brothers' Keepers: Secure Routing with High Performance

abstract:
  The Trinity (Brodsky et al., 2007) spam classification system is based on a
distributed hash table that is implemented using a structured peer-to-peer
overlay. Such an overlay must be capable of processing hundreds of messages per
second, and must be able to route messages to their destination even in the
presence of failures and malicious peers that misroute packets or inject
fraudulent routing information into the system. Typically there is tension
between the requirements to route messages securely and efficiently in the
overlay.
  We describe a secure and efficient routing extension that we developed within
the I3 (Stoica et al. 2004) implementation of the Chord (Stoica et al. 2001)
overlay. Secure routing is accomplished through several complementary
approaches: First, peers in close proximity form overlapping groups that police
themselves to identify and mitigate fraudulent routing information. Second, a
form of random routing solves the problem of entire packet flows passing
through a malicious peer. Third, a message authentication mechanism links each
message to it sender, preventing spoofing. Fourth, each peer's identifier links
the peer to its network address, and at the same time uniformly distributes the
peers in the key-space.
  Lastly, we present our initial evaluation of the system, comprising a 255
peer overlay running on a local cluster. We describe our methodology and show
that the overhead of our secure implementation is quite reasonable.


title: Approximate Killing Fields as an Eigenvalue Problem

abstract:
  Approximate Killing vector fields are expected to help define physically
meaningful spins for non-symmetric black holes in general relativity. However,
it is not obvious how such fields should be defined geometrically. This paper
relates a definition suggested recently by Cook and Whiting to an older
proposal by Matzner, which seems to have been overlooked in the recent
literature. It also describes how to calculate approximate Killing fields based
on these proposals using an efficient scheme that could be of immediate
practical use in numerical relativity.


title: Genus Two Surface and Quarter BPS Dyons: The Contour Prescription

abstract:
  Following the suggestion of hep-th/0506249 and hep-th/0612011, we represent
quarter BPS dyons in N=4 supersymmetric string theories as string network
configuration and explore the role of genus two surfaces in determining the
spectrum of such dyons. Our analysis leads to the correct contour prescription
for integrating the partition function to determine the spectrum in different
domains of the moduli space separated by the walls of marginal stability.


title: Unparticle effects in neutrino telescopes

abstract:
  Recently H.Georgi has introduced the concept of unparticles in order to
describe the low energy physics of a nontrivial scale invariant sector of an
effective theory. We investigate its physical effects on the neutrino flux to
be detected in a kilometer cubic neutrino telescope such as IceCube. We study
the effects, on different observables, of the survival neutrino flux after
through the Earth and the regeneration originated in the neutral currents. We
calculate the contribution of unparticle physics to the neutrino-nucleon
interaction and, then, to the observables in order to evaluate detectable
effects in IceCUbe. Our results are compared with the bounds obtained by other
non-underground experiments. Finally, the results are presented as an exclusion
plot in the relevant parameters of the new physics stuff.


title: Thermal Canting of Spin-Bond Order

abstract:
  Magnetism arising from coupled spin and spatial degrees of freedom underlies
the properties of a broad array of physical systems. We study here the
interplay between correlations in spin and space for the quantum compass model
in a finite external field, using quantum Monte Carlo methods. We find that
finite temperatures cant the spin and space (bond) correlations, with
increasing temperature even reorienting spin correlations between orthogonal
spatial directions. We develop a coupled mean field theory to understand this
effect in terms of the underlying quantum critical properties of crossed Ising
chains in transverse fields and an effective field that weakens upon increasing
temperature. Thermal canting offers an experimental signature of spin-bond
anisotropy.


title: On the chain-level intersection pairing for PL pseudomanifolds

abstract:
  James McClure recently showed that the domain for the intersection pairing of
PL chains on a PL manifold $M$ is a subcomplex of $C_*(M)\otimes C_*(M)$ that
is quasi-isomorphic to $C_*(M)\otimes C_*(M)$ and, more generally, that the
intersection pairing endows $C_*(M)$ with the structure of a partially-defined
commutative DGA. We generalize this theorem to intersection pairings of PL
intersection chains on PL stratified pseudomanifolds and demonstrate the
existence of a partial restricted commutative DGA structure. This structure is
shown to generalize the iteration of the Goresky-MacPherson intersection
product. As an application, we construct an explicit "roof" representation of
the intersection homology pairing in the derived category of sheaves and verify
that this sheaf theoretic pairing agrees with that arising from the geometric
Goresky-MacPherson intersection pairing.


title: Intersection homology Kunneth theorems

abstract:
  Cohen, Goresky and Ji showed that there is a Kunneth theorem relating the
intersection homology groups $I^{\bar p}H_*(X\times Y)$ to $I^{\bar p}H_*(X)$
and $I^{\bar p}H_*(Y)$, provided that the perversity $\bar p$ satisfies rather
strict conditions. We consider biperversities and prove that there is a
K\"unneth theorem relating $I^{\bar p,\bar q}H_*(X\times Y)$ to $I^{\bar
p}H_*(X)$ and $I^{\bar q}H_*(Y)$ for all choices of $\bar p$ and $\bar q$.
Furthermore, we prove that the Kunneth theorem still holds when the
biperversity $p,q$ is "loosened" a little, and using this we recover the
Kunneth theorem of Cohen-Goresky-Ji.


title: The role of microtubule movement in bidirectional organelle transport

abstract:
  We study the role of microtubule movement in bidirectional organelle
transport in Drosophila S2 cells and show that EGFP-tagged peroxisomes in cells
serve as sensitive probes of motor induced, noisy cytoskeletal motions.
Multiple peroxisomes move in unison over large time windows and show
correlations with microtubule tip positions, indicating rapid microtubule
fluctuations in the longitudinal direction. We report the first high-resolution
measurement of longitudinal microtubule fluctuations performed by tracing such
pairs of co-moving peroxisomes. The resulting picture shows that
motor-dependent longitudinal microtubule oscillations contribute significantly
to cargo movement along microtubules. Thus, contrary to the conventional view,
organelle transport cannot be described solely in terms of cargo movement along
stationary microtubule tracks, but instead includes a strong contribution from
the movement of the tracks.


title:
Coupling optical and electrical gating for electronic read-out of
  quantum dot dynamics

abstract:
  We explore the coherent transfer of electronic signatures from a strongly
correlated, optically gated nanoscale quantum dot to a weakly interacting,
electrically backgated microscale channel. In this unique side-coupled `T'
geometry for transport, we predict a novel mechanism for detecting Rabi
oscillations induced in the dot through quantum, rather than electrostatic
means. This detection shows up as a field-tunable split in the Fano lineshape
arising due to interference between the dipole coupled dot states and the
channel continuum. The split is further modified by the Coulomb interactions
within the dot that influence the detuning of the Rabi oscillations.
Furthermore, time-resolving the signal we see clear beats when the Rabi
frequencies approach the intrinsic Bohr frequencies in the dot. Capturing these
coupled dynamics, including memory effects and quantum interference in the
channel and the many-body effects in the dot requires coupling a Fock-space
master equation for the dot dynamics with the phase-coherent, non-Markovian
time-dependent non-equilibrium Green's function (TDNEGF) transport formalism in
the channel through a properly evaluated self-energy and a Coulomb integral.
The strength of the interactions can further be modulated using a backgate that
controls the degree of hybridization and charge polarization at the transistor
surface.


title: Index wiki database: design and experiments

abstract:
  With the fantastic growth of Internet usage, information search in documents
of a special type called a "wiki page" that is written using a simple markup
language, has become an important problem. This paper describes the software
architectural model for indexing wiki texts in three languages (Russian,
English, and German) and the interaction between the software components (GATE,
Lemmatizer, and Synarcher). The inverted file index database was designed using
visual tool DBDesigner. The rules for parsing Wikipedia texts are illustrated
by examples. Two index databases of Russian Wikipedia (RW) and Simple English
Wikipedia (SEW) are built and compared. The size of RW is by order of magnitude
higher than SEW (number of words, lexemes), though the growth rate of number of
pages in SEW was found to be 14% higher than in Russian, and the rate of
acquisition of new words in SEW lexicon was 7% higher during a period of five
months (from September 2007 to February 2008). The Zipf's law was tested with
both Russian and Simple Wikipedias. The entire source code of the indexing
software and the generated index databases are freely available under GPL (GNU
General Public License).


title: On the K-theory of Toric Stack Bundles

abstract:
  Simplicial toric stack bundles are smooth Deligne-Mumford stacks over smooth
varieties with fibre a toric Deligne-Mumford stack. We compute the Grothendieck
$K$-theory of simplicial toric stack bundles and study the Chern character
homomorphism.


title: Superstring Sigma Model Computations Using the Pure Spinor Formalism

abstract:
  In this thesis are presented two aplications of the sigma model for the
superstring in the pure spinor formulation. The first aplication concerns the
computation of the one-loop conformal invariance for the type II superstring,
resulting in equations of motion written in superspace for the background
fields coupled to the superstring. The second application is related to the
BRST invariance of the heterotic superstring at the quantum level, which allows
to find stringy corrections to the ten-dimensional super
Yang-Mills/supergravity constraints.


title: On Hecke Eigenvalues at Piatetski-Shapiro Primes

abstract:
  Let $\lambda(n)$ be the normalized n-th Fourier coefficient of a holomorphic
cusp form for the full modular group. We show that for some constant $C > 0$
depending on the cusp form and every fixed $c$ in the range $1 < c < 8/7$, the
mean value of $\lambda(p)$ is $\ll \exp (-C \sqrt{\log N})$ as p runs over all
(Piatetski-Shapiro) primes of the form $[n^c]$ with a natural number $n \leq
N$.


title:
Particle Acceleration in Solar Flares and Enrichment of 3He and Heavy
  Ions

abstract:
  We discuss possible mechanisms of acceleration of particles in solar flares
and show that turbulence plays an important role in all the mechanism. It is
also argued that stochastic particle acceleration by turbulent plasma waves is
the most likely mechanism for production of the high energy electrons and ions
responsible for observed radiative signatures of solar flares and for solar
energetic particle or SEPs, and that the predictions of this model agrees well
with many past and recent high spectral and temporal observations of solar
flares. It is shown that, in addition, the model explains many features of SEPs
that accompany flares. In particular we show that it can successfully explain
the observed extreme enhancement, relative to photospheric values, of $^3$He
ions and the relative spectra of $^3$He and $^4$He. It has also the potential
of explaining the relative abundances of most ions including the increasing
enhancements of heavy ions with ion mass or mass-to-charge ratio.


title:
Electron-electron interaction effects on the photophysics of metallic
  single-walled carbon nanotubes

abstract:
  Single-walled carbon nanotubes are strongly correlated systems with large
Coulomb repulsion between two electrons occupying the same $p_z$ orbital.
Within a molecular Hamiltonian appropriate for correlated $\pi$-electron
systems, we show that optical excitations polarized parallel to the nanotube
axes in the so-called metallic single-walled carbon nanotubes are to excitons.
Our calculated absolute exciton energies in twelve different metallic
single-walled carbon nanotubes, with diameters in the range 0.8 - 1.4 nm, are
in nearly quantitative agreement with experimental results. We have also
calculated the absorption spectrum for the (21,21) single-walled carbon
nanotube in the E$_{22}$ region. Our calculated spectrum gives an excellent fit
to the experimental absorption spectrum. In all cases our calculated exciton
binding energies are only slightly smaller than those of semiconducting
nanotubes with comparable diameters, in contradiction to results obtained
within the {\it ab initio} approach, which predicts much smaller binding
energies. We ascribe this difference to the difficulty of determining the
behavior of systems with strong on-site Coulomb interactions within theories
based on the density functional approach. As in the semiconducting nanotubes we
predict in the metallic nanotubes a two-photon exciton above the lowest
longitudinally polarized exciton that can be detected by ultrafast pump-probe
spectroscopy. We also predict a subgap absorption polarized perpendicular to
the nanotube axes below the lowest longitudinal exciton, blueshifted from the
exact midgap by electron-electron interactions.


title: Rabi oscillations and photocurrent in quantum-dot tunnelling junctions

abstract:
  Motivated by the experiments by Zrenner et al. [Nature 418, 612 (2002)], we
study the influence of relaxation processes on converting Rabi oscillations in
a strongly biased single-quantum-dot photodiode into deterministic
photocurrents. We show that the behavior of a quantum dot with different tunnel
rates for electron and holes is qualitatively different from that with the
equal tunnel rates: in the latter case the current shows attenuating
oscillations with the Rabi frequency. In contrast, for different electrons and
holes tunnelling rates, the frequency of these oscillations diminishes, and
they disappear beyond a definite asymmetry threshold. We give an analytical
solution of the problem and a numerical example showing a different behaviour
of the transferred charge in the small attenuation limit for equal and
different tunnel rates for electrons and holes.


title: A relative version of Kummer theory

abstract:
  Let $E/F$ be a cyclic Galois extension of degree $p^l$ with Galois group $G$.
It is shown that the Galois module structure of both sides of the Kummer
pairing (for Kummer extensions of $E$) are the same. In other words, we show
that the Kummer duality holds in the level of finitely generated $G$-modules.


title: Injective and non-injective realizations with symmetry

abstract:
  In this paper, we introduce a natural classification of bar and joint
frameworks that possess symmetry. This classification establishes the
mathematical foundation for extending a variety of results in rigidity, as well
as infinitesimal or static rigidity, to frameworks that are realized with
certain symmetries and whose joints may or may not be embedded injectively in
the space. In particular, we introduce a symmetry-adapted notion of `generic'
frameworks with respect to this classification and show that `almost all'
realizations in a given symmetry class are generic and all generic realizations
in this class share the same infinitesimal rigidity properties. Within this
classification we also clarify under what conditions group representation
theory techniques can be applied to further analyze the rigidity properties of
a (not necessarily injective) symmetric realization.


title: Communication Complexities of XOR functions

abstract:
  We call $F:\{0, 1\}^n\times \{0, 1\}^n\to\{0, 1\}$ a symmetric XOR function
if for a function $S:\{0, 1, ..., n\}\to\{0, 1\}$, $F(x, y)=S(|x\oplus y|)$,
for any $x, y\in\{0, 1\}^n$, where $|x\oplus y|$ is the Hamming weight of the
bit-wise XOR of $x$ and $y$.
  We show that for any such function, (a) the deterministic communication
complexity is always $\Theta(n)$ except for four simple functions that have a
constant complexity, and (b) up to a polylog factor, the error-bounded
randomized and quantum communication complexities are $\Theta(r_0+r_1)$, where
$r_0$ and $r_1$ are the minimum integers such that $r_0, r_1\leq n/2$ and
$S(k)=S(k+2)$ for all $k\in[r_0, n-r_1)$.


title:
CMB polarimetry with BICEP: instrument characterization, calibration,
  and performance

abstract:
  BICEP is a ground-based millimeter-wave bolometric array designed to target
the primordial gravity wave signature on the polarization of the cosmic
microwave background (CMB) at degree angular scales. Currently in its third
year of operation at the South Pole, BICEP is measuring the CMB polarization
with unprecedented sensitivity at 100 and 150 GHz in the cleanest available 2%
of the sky, as well as deriving independent constraints on the diffuse
polarized foregrounds with select observations on and off the Galactic plane.
Instrument calibrations are discussed in the context of rigorous control of
systematic errors, and the performance during the first two years of the
experiment is reviewed.


title: Did Gravitational Waves Affect the Evolution of the Universe?

abstract:
  As Cosmologists struggle to understand the evolution of our universe, an
often over-looked element is the affect of gravitational radiation on the
primordial plasma field. This appears to be due to the inaccurate approximation
of the primordial plasma field as a simple hydrodynamic fluid, therefore
neglecting the full dynamics of the magneto-fluid. In this paper, we show how
gravitational waves may have had a significant impact on the evolution of our
universe. While more work is needed, the author hopes to eventually develop a
large-scale simulation of structure formation in the early universe, which
takes the interactions of scalar perturbations, gravitational waves, magnetic
fields and a dynamic plasma field into account.


title:
Planetary systems around close binary stars: the case of the very dusty,
  Sun-like, spectroscopic binary BD+20 307

abstract:
  Field star BD+20 307 is the dustiest known main sequence star, based on the
fraction of its bolometric luminosity, 4%, that is emitted at infrared
wavelengths. The particles that carry this large IR luminosity are unusually
warm, comparable to the temperature of the zodiacal dust in the solar system,
and their existence is likely to be a consequence of a fairly recent collision
of large objects such as planets or planetary embryos. Thus, the age of BD+20
307 is potentially of interest in constraining the era of terrestrial planet
formation. The present project was initiated with an attempt to derive this age
using the Chandra X-ray Observatory to measure the X-ray flux of BD+20 307 in
conjunction with extensive photometric and spectroscopic monitoring
observations from Fairborn Observatory. However, the recent realization that
BD+20 307 is a short period, double-line, spectroscopic binary whose components
have very different lithium abundances, vitiates standard methods of age
determination. We find the system to be metal-poor; this, combined with its
measured lithium abundances, indicates that BD+20 307 may be several to many
Gyr old. BD+20 307 affords astronomy a rare peek into a mature planetary system
in orbit around a close binary star (because such systems are not amenable to
study by the precision radial velocity technique).


title: The Optimal Quantile Estimator for Compressed Counting

abstract:
  Compressed Counting (CC) was recently proposed for very efficiently computing
the (approximate) $\alpha$th frequency moments of data streams, where $0<\alpha
<= 2$. Several estimators were reported including the geometric mean estimator,
the harmonic mean estimator, the optimal power estimator, etc. The geometric
mean estimator is particularly interesting for theoretical purposes. For
example, when $\alpha -> 1$, the complexity of CC (using the geometric mean
estimator) is $O(1/\epsilon)$, breaking the well-known large-deviation bound
$O(1/\epsilon^2)$. The case $\alpha\approx 1$ has important applications, for
example, computing entropy of data streams.
  For practical purposes, this study proposes the optimal quantile estimator.
Compared with previous estimators, this estimator is computationally more
efficient and is also more accurate when $\alpha> 1$.


title:
Quantum Statistical Mechanics of $\mathbb{Q}$-lattices and
  noncommutative geometry

abstract:
  After recalling some basic notions of quantum statistical mechanics, we
explain the Bost-Connes system that relates the structure of the maximal
abelian extension of $\mathbb{Q}$ to the space of \kms states of a
\cs-dynamical system. Afterwards, we study briefly the Connes-Marcolli
$\text{GL}_2$-system as a generalization of the former system.


title:
Quadratic fermionic interactions yield effective Hamiltonians for
  adiabatic quantum computing

abstract:
  Polynomially-large ground-state energy gaps are rare in many-body quantum
systems, but useful for adiabatic quantum computing. We show analytically that
the gap is generically polynomially-large for quadratic fermionic Hamiltonians.
We then prove that adiabatic quantum computing can realize the ground states of
Hamiltonians with certain random interactions, as well as the ground states of
one, two, and three-dimensional fermionic interaction lattices, in polynomial
time. Finally, we use the Jordan-Wigner transformation and a related
transformation for spin-3/2 particles to show that our results can be restated
using spin operators in a surprisingly simple manner. A direct consequence is
that the one-dimensional cluster state can be found in polynomial time using
adiabatic quantum computing.


title:
Spectroscopic Confirmation of the Fifth Image of SDSS J1004+4112 and
  Implications for the M_BH-sigma_* Relation at z=0.68

abstract:
  We present the results of deep spectroscopy for the central region of the
cluster lens SDSS J1004+4112 with the Subaru telescope. A secure detection of
an emission line of the faint blue stellar object (component E) near the center
of the brightest cluster galaxy (G1) confirms that it is the central fifth
image of the lensed quasar system. In addition, we measure the stellar velocity
dispersion of G1 to be sigma_* = 352+-13 km/s. We combine these results to
obtain constraints on the mass M_BH of the putative black hole (BH) at the
center of the inactive galaxy G1, and hence on the M_BH-sigma_* relation at the
lens redshift z_l=0.68. From detailed mass modeling, we place an upper limit on
the black hole mass, M_BH < 2.1x10^{10}M_sun at 1-sigma level
(<3.1x10^{10}M_sun at 3-sigma), which is consistent with black hole masses
expected from the local and redshift-evolved M_BH-sigma_* relations,
M_BH~10^{9}-10^{10}M_sun.


title:
Superharmonic Perturbations of a Gaussian Measure, Equilibrium Measures
  and Orthogonal Polynomials

abstract:
  This work concerns superharmonic perturbations of a Gaussian measure given by
a special class of positive weights in the complex plane of the form $w(z) =
\exp(-|z|^2 + U^{\mu}(z))$, where $U^{\mu}(z)$ is the logarithmic potential of
a compactly supported positive measure $\mu$. The equilibrium measure of the
corresponding weighted energy problem is shown to be supported on subharmonic
generalized quadrature domains for a large class of perturbing potentials
$U^{\mu}(z)$. It is also shown that the $2\times 2$ matrix d-bar problem for
orthogonal polynomials with respect to such weights is well-defined and has a
unique solution given explicitly by Cauchy transforms. Numerical evidence is
presented supporting a conjectured relation between the asymptotic distribution
of the zeroes of the orthogonal polynomials in a semi-classical scaling limit
and the Schwarz function of the curve bounding the support of the equilibrium
measure, extending the previously studied case of harmonic polynomial
perturbations with weights $w(z)$ supported on a compact domain.


title:
A Very Efficient Scheme for Estimating Entropy of Data Streams Using
  Compressed Counting

abstract:
  Compressed Counting (CC)} was recently proposed for approximating the
$\alpha$th frequency moments of data streams, for $0<\alpha \leq 2$. Under the
relaxed strict-Turnstile model, CC dramatically improves the standard algorithm
based on symmetric stable random projections}, especially as $\alpha\to 1$. A
direct application of CC is to estimate the entropy, which is an important
summary statistic in Web/network measurement and often serves a crucial
"feature" for data mining. The R\'enyi entropy and the Tsallis entropy are
functions of the $\alpha$th frequency moments; and both approach the Shannon
entropy as $\alpha\to 1$. A recent theoretical work suggested using the
$\alpha$th frequency moment to approximate the Shannon entropy with
$\alpha=1+\delta$ and very small $|\delta|$ (e.g., $<10^{-4}$).
  In this study, we experiment using CC to estimate frequency moments, R\'enyi
entropy, Tsallis entropy, and Shannon entropy, on real Web crawl data. We
demonstrate the variance-bias trade-off in estimating Shannon entropy and
provide practical recommendations. In particular, our experiments enable us to
draw some important conclusions:
  (1) As $\alpha\to 1$, CC dramatically improves {\em symmetric stable random
projections} in estimating frequency moments, R\'enyi entropy, Tsallis entropy,
and Shannon entropy. The improvements appear to approach "infinity."
  (2) Using {\em symmetric stable random projections} and $\alpha = 1+\delta$
with very small $|\delta|$ does not provide a practical algorithm because the
required sample size is enormous.


title:
Effective mass calculations of SrTiO3-based superlattices for
  thermoelectric applications lead to new layer design

abstract:
  The effective mass is one of the main factors for enlarging the Seebeck
coefficient and electronic conductivity of SrTiO3-based thermoelectric
materials [1,2]. The goal of this paper is to clarify, how superlattices can
change the effective mass and other features of the bandstructure. The natural
Ruddlesden-Popper phase (SrTiO3)n(SrO)m with n=2, m=1 the situation changes,
because the TiO6-octahedrons are slightly extended, due to diluted density of
the SrO layer. Another effect is the deformed electron density, which leads to
reduced effective mass perpendicular to the layer, but enlarged parallel to the
plane [3]. The average value of the effective mass over this anisotropy of the
2-dimensional electron gas (2DEG) for pure Ruddlesden-Popper phases is smaller,
but can increase beyond the value of pure Pervoskite for certain doping
elements. In the same way, artificial superlattices (SrTiO3)x/(SrTi1-z(Nb)zO3)y
were examined. When fine nanostructures (n=2, m=3 or n=3, m=2) are present the
effective mass increases, when the structure becomes coarser (n=4, m=1) smaller
values are determined.


title:
"I Know She Invented Fire, but What Has She Done Recently?" or "I Have
  Come to Praise Ch., not Bury Her!" or `On the Second Renaissance of Charm
  Physics'

abstract:
  $D^0$ oscillations, for which the $B$ factories have found strong evidence,
provide a new stage for our search for New Physics in heavy flavour dynamics.
While the theoretical verdict on the observed values of $x_D$ and $y_D$ is
ambiguous -- they could be fully generated by SM dynamics, yet could contain
also a sizable contribution from New Physics -- such oscillations can enhance
the observability of \cp violation driven by New Physics. After emphasizing the
unique role of charm among up-type quarks, I sketch the \cp phenomenology for
partial widths and final state distributions.


title:
Nonpositively curved metric in the positive cone of a finite von Neumann
  algebra

abstract:
  In this paper we study the metric geometry of the space $\Sigma$ of positive
invertible elements of a von Neumann algebra ${\mathcal A}$ with a finite,
normal and faithful tracial state $\tau$. The trace induces an incomplete
Riemannian metric $<x,y>_a=\tau (ya^{-1}xa^{-1})$, and though the techniques
involved are quite different, the situation here resembles in many relevant
aspects that of the $n\times n$ matrices when they are regarded as a symmetric
space. For instance we prove that geodesics are the shortest paths for the
metric induced, and that the geodesic distance is a convex function; we give an
intrinsic (algebraic) characterization of the geodesically convex submanifolds
$M$ of $\Sigma$, and under suitable hypothesis we prove a factorization theorem
for elements in the algebra that resembles the Iwasawa decomposition for
matrices. This factorization is obtained \textit{via} a nonlinear orthogonal
projection $\Pi_M:\Sigma\to M$, a map which turns out to be contractive for the
geodesic distance.


title: Indecomposable $PD_3$-complexes

abstract:
  We show that if $X$ is an indecomposable $PD_3$-complex and $\pi_1(X) is the
fundamental group of a reduced finite graph of finite groups but is not
virtually cyclic then $X$ is orientable, the underlying graph is a tree, all
the edge groups are $Z/2Z$ and all but at most one of the vertex groups is
dihedral of order $2m$ with $m$ odd. Every such group is realized by some
$PD_3$-complex.
  We also propose a strategy for tackling the question of whether every
$PD_3$-complex has a finite covering space which is homotopy equivalent to a
closed orientable 3-manifold.


title: Open flavour Charmed Mesons

abstract:
  We present here recent results on the investigations of the mass spectrum
(S-states and P-states), decay constants, decay widths and life time of the D,
$D_s$,and $B_c$mesons within the framework of phenomenological potential
models.We also present the binding energy and the masses of the di-meson
molecular systems with one or more charm meson combinations. Many of the newly
found experimental open charm states are identified with the orbital
excitations of the conventional open charm mesons while others like X(3872),
Y(3930), $D_{sJ}$(2632, 2700) \emph{etc.}, are identified as molecular like
states.


title: Spin-charge Separation in Nodal Antiferromagnetic Insulator

abstract:
  In this paper, by using two dimensional (2D) Hubbard models with pi-flux
phase and that on a hexagonal lattice as examples, we explore
spin-charge-separated solitons in nodal antiferromagnetic (AF) insulator - an
AF order with massive Dirac fermionic excitations (see detail in the paper). We
calculate fermion zero modes and induced quantum numbers on solitons (half
skyrmions) in the continuum limit, which are similar to that in the quasi
one-dimensional conductor polyacetylene (CH)x and that in topological band
insulator. In particular, we find some novel phenomena : thanks to an induced
staggered spin moment, a mobile half skyrmion becomes a fermionic particle;
when a hole or an electron is added, the half skyrmion turns into a bosonic
particle with charge degree of freedom only. Our results imply that nontrivial
induced quantum number on solitons may be a universal feature of spin-charge
separation in different systems.


title: Frame-like gauge invariant formulation for massive high spin particles

abstract:
  In this paper we extend a so called frame-like formulation of massless high
spin particles to massive case. We start with two explicit examples of massive
spin 2 and spin 3 particles and then construct gauge invariant description for
arbitrary integer spin case. Similarly, for the fermionic case we start with
first non-trivial example -- massive spin 5/2 particle and then construct gauge
invariant description for arbitrary half-integer spin case. In all cases we
consider massive particles in (A)dS spaces with arbitrary cosmological constant
(including flat Minkowski space) and this allows one to investigate all
possible massless and partially massless limits for such particles.


title:
Spin Filter, Spin Amplifier and Other Spintronic Applications in
  Graphene Nanodisks

abstract:
  Graphene nanodisk is a graphene derivative with a closed edge. The trigonal
zigzag nanodisk with size $N$ has $N$-fold degenerated zero-energy states. A
nanodisk can be interpletted as a quantum dot with an internal degree of
freedom. The grand state of nanodisk has been argued to be a quasi-ferromagnet,
which is a ferromagnetic-like states with a finite but very long life time. We
investigate the spin-filter effects in the system made of nanodisks and leads
based on the master equation. The finite-size effect on spin filter is
intriguing due to a reaction from the polarization of incoming current to a
quasi-ferromagnet. Analyzing the relaxation process with the use of the
Landau-Lifshitz-Gilbert equation, we explore the response to four types of
incoming currents, namely, unpolarized current, perfectly polarized current,
partially polarized current and pulse polarized current. We propose some
applications for spintronics, such as spin memory, spin amplifier, spin valve,
spin-field-effect transistor and spin diode.


title: Wobbling of What?

abstract:
  A simple explanation for the symmetry of the genetic code has been suggested.
An alternative to the wobble hypothesis has been proposed. The facts revealed
in this study offer a new insight into physical mechanisms of the functioning
of the genetic code.


title: Spin-Domain Formation in Antiferromagnetic Condensates

abstract:
  Antiferromagnetic condensates are generally believed not to display
modulational instability and subsequent spin-domain formation. Here we
demonstrate that in he presence of a homogeneous magnetic field
antiferromagnetic spin-1 Bose-Einstein condensates can undergo spatial
modulational instability followed by the subsequent generation of spin domains.
Employing numerical simulations for realistic conditions, we show how this
novel effect can be observed in sodium condensates confined in an optical trap.
Finally, we link this instability and spin-domain formation with stationary
modes of the condensate.


title: Architectural design for a topological cluster state quantum computer

abstract:
  The development of a large scale quantum computer is a highly sought after
goal of fundamental research and consequently a highly non-trivial problem.
Scalability in quantum information processing is not just a problem of qubit
manufacturing and control but it crucially depends on the ability to adapt
advanced techniques in quantum information theory, such as error correction, to
the experimental restrictions of assembling qubit arrays into the millions. In
this paper we introduce a feasible architectural design for large scale quantum
computation in optical systems. We combine the recent developments in
topological cluster state computation with the photonic module, a simple chip
based device which can be used as a fundamental building block for a large
scale computer. The integration of the topological cluster model with this
comparatively simple operational element addresses many significant issues in
scalable computing and leads to a promising modular architecture with complete
integration of active error correction exhibiting high fault-tolerant
thresholds.


title: Criticality in the Quantum Kicked Rotor with a Smooth Potential

abstract:
  We investigate the possibility of an Anderson type transition in the quantum
kicked rotor with a smooth potential due to dynamical localization of the
wavefunctions. Our results show the typical characteristics of a critical
behavior i.e multifractal eigenfunctions and a scale-invariant level-statistics
at a critical kicking strength which classically corresponds to a mixed regime.
This indicates the existence of a localization to delocalization transition in
the quantum kicked rotor.
  Our study also reveals the possibility of other type of transitions in the
quantum kicked rotor, with a kicking strength well within strongly chaotic
regime. These transitions, driven by the breaking of exact symmetries e.g.
time-reversal and parity, are similar to weak-localization transitions in
disordered metals.


title:
Superconductivity in layered iron Selenide induced by cobalt- and
  sodium-doping

abstract:
  Superconductivity with zero resistance transition temperature (Tc) up to 8.4
K and 8.3 K can be obtained by doping cobalt and sodium in alfa-FeSe with the
nominal composition of Fe0.92Co0.08Se and Na0.1FeSe, respectively. The
electrical resistivity and AC magnetic susceptibility of the prepared samples,
measured with physical property measurement system (PPMS), unambiguously
consistent with each other to indicate that the samples are superconductive.
The respective doping mechanisms for cobalt and sodium into the parent
alfa-FeSe are the Fe-site substitution and the interlayer insertion. It is the
first time that alfa-FeSe can be induced to be a superconductor with Na+
intercalated into the interlayers.


title:
The structure and dynamics of young star clusters: King 16, NGC 1931,
  NGC 637 and NGC 189

abstract:
  In this paper, using 2MASS photometry, we study the structural and dynamical
properties of four young star clusters viz. King 16, NGC 1931, NGC 637 and NGC
189. For the clusters King 16, NGC 1931, NGC 637 and NGC 189, we obtain the
limiting radii of 7', 12', 6' and 5' which correspond to linear radii of 3.6
pc, 8.85 pc, 3.96 pc and 2.8 pc respectively. The reddening values $E(B-V)$
obtained for the clusters are 0.85, 0.65--0.85, 0.6 and 0.53 and their true
distances are 1786 pc, 3062 pc, 2270 pc and 912 pc respectively. Ages of the
clusters are 6 Myr, 4 Myr, 4 Myr and 10 Myr respectively. We compare their
structures, luminosity functions and mass functions ($\phi(M) = dN/dM \propto
M^{-(1+\chi)}$) to the parameter $\tau = t_{age}/t_{relax}$ to study the star
formation process and the dynamical evolution of these clusters. We find that,
for our sample, mass seggregation is observed in clusters or their cores only
when the ages of the clusters are comparable to their relaxation times ($\tau
\geq 1$). These results suggest mass seggregation due to dynamical effects. The
values of $\chi$, which characterise the overall mass functions for the
clusters are 0.96 $\pm$ 0.11, 1.16 $\pm$ 0.18, 0.55 $\pm$ 0.14 and 0.66 $\pm$
0.31 respectively. The change in $\chi$ as a function of radius is a good
indicator of the dynamical state of clusters.


title:
Generation of fluctuations during inflation: comparison of stochastic
  and field-theoretic approaches

abstract:
  We prove that the stochastic and standard field-theoretical approaches
produce exactly the same results for the amount of light massive scalar field
fluctuations generated during inflation in the leading order of the slow-roll
approximation. This is true both in the case for which this field is a test one
and inflation is driven by another field, and the case for which the field
plays the role of inflaton itself. In the latter case, in order to calculate
the average of the mean square of the gauge-invariant inflaton fluctuation, the
logarithm of the scale factor $a$ has to be used as the time variable in the
Fokker-Planck equation in the stochastic approach. The implications of particle
production during inflation for the second stage of inflation and for the
moduli problem are also discussed. The case of a massless self-interacting test
scalar field in a de Sitter background with a zero initial renormalized mean
square is also considered in order to show how the stochastic approach can
easily produce results corresponding to diagrams with an arbitrary number of
scalar field loops in the field-theoretical approach (explicit results up to 4
loops inclusive are presented).


title: Transitive-Closure Spanners

abstract:
  Given a directed graph G = (V,E) and an integer k>=1, a
k-transitive-closure-spanner (k-TC-spanner) of G is a directed graph H = (V,
E_H) that has (1) the same transitive-closure as G and (2) diameter at most k.
These spanners were implicitly studied in access control, data structures, and
property testing, and properties of these spanners have been rediscovered over
the span of 20 years. The main goal in each of these applications is to obtain
the sparsest k-TC-spanners. We bring these diverse areas under the unifying
framework of TC-spanners.
  We initiate the study of approximability of the size of the sparsest
k-TC-spanner for a given directed graph. We completely resolve the
approximability of 2-TC-spanners, showing that it is Theta(log n) unless P =
NP. For k>2, we present a polynomial-time algorithm that finds a k-TC-spanner
with size within O((n log n)^{1-1/k}) of the optimum. Our algorithmic
techniques also yield algorithms with the best-known approximation ratio for
well-studied problems on directed spanners when k>3: DIRECTED k-SPANNER,
CLIENT/SERVER DIRECTED k-SPANNER, and k-DIAMETER SPANNING SUBGRAPH. For
constant k>=3, we show that the size of the sparsest k-TC-spanner is hard to
approximate with 2^{log^{1-eps} n} ratio unless NP \subseteq DTIME(n^{polylog
n}}). Finally, we study the size of the sparsest k-TC-spanners for H-minor-free
graph families. Combining our constructions with our insight that 2-TC-spanners
can be used for designing property testers, we obtain a monotonicity tester
with O(log^2 n /eps) queries for any poset whose transitive reduction is an
H-minor free digraph, improving the Theta(sqrt(n) log n/eps)-queries required
of the tester due to Fischer et al (2002).


title: Some extensions of the class of convex bodies

abstract:
  We introduce and study a new class of $\eps$-convex bodies (extending the
class of convex bodies) in metric and normed linear spaces. We analyze
relations between characteristic properties of convex bodies, demonstrate how
$\eps$-convex bodies connect with some classical results of Convex Geometry, as
Helly theorem, and find applications to geometric tomography. We introduce the
notion of a circular projection and investigate the problem of determination of
$\eps$-convex bodies by their projection-type images. The results generalize
corresponding stability theorems by H. Groemer.


title:
The NGC 672 and NGC 784 Galaxy Groups: Evidence for Galaxy Formation and
  Growth Along a Nearby Dark Matter Filament

abstract:
  (Abridged): We present U, B, V, R, I, H-alpha and NUV photometry of 14
galaxies in the very local Universe (within 10 Mpc that are dwarf irregular
galaxies (dIrr), are at low redshift (51<v<610 km/s), and appear as a six
degree long linear filament.. We examine the star formation (SF) properties of
individual objects with the current SF rate (SFR) derived directly from the
H-alpha line flux and compare the multi-band photometry with results of galaxy
evolution assuming short SF bursts separated by long quiescence periods. Most
objects contain at least one "old" stellar population (>1-10 Gyr) and one
"young" population (<30 Myr) with the recent SF bursts occurring a few to a few
10s of Myr ago, arguing for synchronicity in star formation in these objects.
We propose that the ~synchronous star formation in all objects is caused by the
accretion of cold gas from intergalactic space onto dark matter haloes arranged
along a filament threading the void where these dwarf galaxies reside and point
out this galaxy sample as an ideal target to study hierarchical clustering and
galaxy formation among very nearby objects.


title:
Magnetic flux penetration and AC loss in a composite superconducting
  wire with ferromagnetic parts

abstract:
  The current distribution and the AC loss in a composite superconducting tape
containing a layer from magnetic material is calculated and compared with
experiments, showing a very good agreement. The situations of an alternating
uniform applied field or a transport current are studied. The newly developed
numerical model is an approximation to the critical state model, adapted for
the applicability to commercial finite elements codes that solve the vector
potential. Substantial feature of this procedure is that it can be carried out
in the case when the critical current density in superconductor depends on the
magnetic field and the magnetic layer material is non- linear. Additionally,
the hysteresis loss in the magnetic material is estimated, based on its
measured magnetization loops. Measurements on Bi-2223 multifilamentary tapes
covered on edges by nickel confirmed our predictions, showing a substantial ac
loss reduction in both the investigated regimes.


title:
Perturbative calculations for the HISQ action: the gluon action at
  $O(N_f\alpha_sa^2)$

abstract:
  We present a new (and general) algorithm for deriving lattice Feynman rules
which is capable of handling actions as complex as the Highly Improved
Staggered Quark (HISQ) action. This enables us to perform a perturbative
calculation of the influence of dynamical HISQ fermions on the perturbative
improvement of the gluonic action in the same way as we have previously done
for asqtad fermions. We find the fermionic contributions to the radiative
corrections in the L\"uscher-Weisz gauge action to be somewhat larger for HISQ
fermions than for asqtad.


title:
On the number of allelic types for samples taken from exchangeable
  coalescents with mutation

abstract:
  Let $K_n$ denote the number of types of a sample of size $n$ taken from an
exchangeable coalescent process ($\Xi$-coalescent) with mutation. A
distributional recursion for the sequence $(K_n)_{n\in{\mathbb N}}$ is derived.
If the coalescent does not have proper frequencies, i.e., if the characterizing
measure $\Xi$ on the infinite simplex $\Delta$ does not have mass at zero and
satisfies $\int_\Delta |x|\Xi(dx)/(x,x)<\infty$, where $|x|:=\sum_{i=1}^\infty
x_i$ and $(x,x):=\sum_{i=1}^\infty x_i^2$ for $x=(x_1,x_2,...)\in\Delta$, then
$K_n/n$ converges weakly as $n\to\infty$ to a limiting variable $K$ which is
characterized by an exponential integral of the subordinator associated with
the coalescent process. For so-called simple measures $\Xi$ satisfying
$\int_\Delta\Xi(dx)/(x,x)<\infty$ we characterize the distribution of $K$ via a
fixed-point equation.


title: Curvaton with Polynomial Potential

abstract:
  In general a weakly self-interacting curvaton field is expected and the
curvaton potential takes the polynomial form. The curvaton potential can be
dominated by the self-interaction term during the period of inflation if the
curvaton field stays at a large vacuum expectation value. We use the $\delta
{\cal N}$ formalism to calculate the primordial curvature perturbation in the
various possible scenarios which make the curvaton model much richer.


title: Neon and Chemical Fractionation Trends in Late-type Stellar Atmospheres

abstract:
  A survey of Ne, O and Fe coronal abundances culled from the recent literature
for about 60 late-type stars confirms that the Ne/O ratio of stellar outer
atmospheres is about two times the value recently recommended by Asplund et al.
The mean Ne/O remains flat from the most active stars down to at least
intermediate activity levels (-5L_X/L_bol<-2), with some evidence for a decline
toward the lowest activity levels sampled. The abundances surveyed are all
based on emission measure distribution analyses and the mean Ne/O is about 0.1
dex lower than that found from line ratios in the seminal study of mostly
active stars by Drake & Testa (2005), but is within the systematic
uncertainties of that study. We also confirm a pattern of strongly decreasing
Fe/O with increasing stellar activity. The observed abundance patterns are
reminiscent of the recent finding of a dependence of the solar Ne/O and Fe/O
ratios on active region plasma temperature and indicate a universal
fractionation process is at work. The firm saturation in stellar Ne/O at higher
activity levels combined with variability in the solar coronal Ne/O leads us to
suggest that Ne is generally depleted in the solar outer atmosphere and
photospheric values are reflected in active stellar coronae. The solution to
the recent solar model problem would then appear to lie in a combination of the
Asplund et al O abundance downward revision being too large, and the Ne
abundance being underestimated for the Sun by about a factor of 2.


title: A classification of smooth embeddings of 4-manifolds in 7-space, II

abstract:
  Let N be a closed, connected, smooth 4-manifold with H_1(N;Z)=0. Our main
result is the following classification of the set E^7(N) of smooth embeddings
N->R^7 up to smooth isotopy. Haefliger proved that the set E^7(S^4) with the
connected sum operation is a group isomorphic to Z_{12}. This group acts on
E^7(N) by embedded connected sum. Boechat and Haefliger constructed an
invariant BH:E^7(N)->H_2(N;Z) which is injective on the orbit space of this
action; they also described im(BH). We determine the orbits of the action: for
u in im(BH) the number of elements in BH^{-1}(u) is GCD(u/2,12) if u is
divisible by 2, or is GCD(u,3) if u is not divisible by 2. The proof is based
on a new approach using modified surgery as developed by Kreck.


title:
A study of quark-gluon vertices using the lattice Coulomb gauge domain
  wall fermion

abstract:
  I calculate the quark-gluon vertex of the tensor type
$\Gamma(p,q)=g_3(p,q)p_4 \Slash{\Vec q}$, vector type $g_2(p,q)\Vec q$ and
scalar type $g_1(p,q)$, for a small spacial momentum transfer $q=\bf q$ using
the gauge configuration of the Domain Wall Fermion (DWF) provided by the
RBC-UKQCD collaboration.
  The quark propagator of Coulomb gauge in the cylinder cut, i.e. the four
momentum $p$ is directed along the diagonal of the hyper-cubic space has small
fluctuation and I use this propagator in the evaluation of the operators by
applying the non-perturbative renormalization method.
  The $q$ dependence of the running coupling $\alpha_{s,g_1}(q)$ is compared
with $\alpha_I(q)$ measured by the ghost-gluon vertex in Coulomb gauge and
$\alpha_s(q)$ measured in Landau gauge.


title: On the Production of Jets and Hadrons

abstract:
  The ratio of the semivertical cone angles of the quark and gluon jets
calculated in the statistical model is found to be in exact agreement with that
derived from QCD.In hadron production also,the model's prediction of the power
law type of behaviour for the inclusive distribtuion is strikingly close to the
the corresponding experimental findings;these spectacular results are
significant for the model to be realistic.


title:
Quantum Time-evolution in Qubit Readout Process with a Josephson
  Bifurcation Amplifier

abstract:
  We analyzed the Josephson bifurcation amplifier (JBA) readout process of a
superconducting qubit quantum mechanically. This was achieved by employing
numerical analyses of the dynamics of the density operator of a driven
nonlinear oscillator and a qubit coupled system during the measurement process.
In purely quantum cases, the wavefunction of the JBA is trapped in a
quasienergy-state, and bifurcation is impossible. Introducing decoherence
enables us to reproduce the bifurcation with a finite hysteresis. Moreover, we
discuss in detail the dynamics involved when a qubit is initially in a
superposition state. We have observed the qubit-probe (JBA) entangled state and
it is divided into two separable states at the moment of the JBA transition
begins. This corresponds to "projection". To readout the measurement result,
however, we must wait until the two JBA states are macroscopically well
separated. The waiting time is determined by the strength of the decoherence in
the JBA.


title: BRST Exact Action For N=1, D=4, Supersymmetric Yang-Mills Theory

abstract:
  The action for classical and consequently quantum N=1, D=4, supersymmetric
Yang-Mills theories is proven to be written as a BRST exact term. In order to
show this, the space of fields in the theory must be enlarged to include an
extrafield as a non dynamical auxiliary field.


title:
Renormalization of O(N) model in 1/N expansion in auxiliary field
  formalism

abstract:
  We study the renormalization of the O(N) model using the auxiliary field
formalism (Hubbard-Stratonovich transformation) in the 1/N expansion at finite
temperature. We provide the general strategy of renormalization for arbitrary
order, and make calculation up to next-to-leading order. We show that
renormalization is possible for any values of the condensates, prove the
temperature independence of the counterterms and determine the cutoff
dependence of the first nontrivial counterterm parts.


title:
Multidirectional analysis of the oscillating (T = 24 hours) Earth's
  electric field recorded on ground surface

abstract:
  The Earth's preseismic oscillating (T = 24h) electric field recorded for a
short-time period of some days is analyzed in terms of its intensity vector
azimuthal direction calculated at one monitoring site. The calculated azimuthal
directions are compared to the concurrent seismicity observed for the same
period of time. Examples are presented for proving the agreement between the
electric field intensity vectors calculated azimuths and the corresponding ones
referring to the EQs - monitoring site location. Finally, an example is
presented on account of the use of this methodology upon three different
monitoring sites for the utilization of the estimation of the epicentral area
of a large future EQ at the Methoni, Greece seismogenic area.


title: Compute and Storage Clouds Using Wide Area High Performance Networks

abstract:
  We describe a cloud based infrastructure that we have developed that is
optimized for wide area, high performance networks and designed to support data
mining applications. The infrastructure consists of a storage cloud called
Sector and a compute cloud called Sphere. We describe two applications that we
have built using the cloud and some experimental studies.


title: Jet modification in 200 AGeV Au-Au collisions

abstract:
  The computation of hard processes in hadronic collisions is a major success
of perturbative Quantum Chromodynamics. The environment of heavy-ion collisions
offers the opportunity to embed such hard processes into a soft medium which is
created simultaneously and study the medium-induced modifications. On the level
of single high transverse momentum hadrons, a reduction in yield, the so-called
quenching is observed. However, on the level of jets, the energy-momentum flux
carried by hadrons is conserved, i.e. the effect of the medium is a
redistribution of energy and momentum, and statements about quenching of jets
can only be made for specific cuts used to identify the jet. In this paper, we
present a baseline computation for the expected modification of the
longitudinal momentum distribution in jets by the medium created in 200 AGeV
Au-Au collisions given a realistic set of experimental cuts used to identify
jets in a heavy-iron environment. For this purpose, we use a Monte-Carlo code
developed to simulate in-medium shower evolution following a hard process and a
3-d hydrodynamical evolution to simulate the soft medium.


title: Parity Violating Effects in Elastic Electron Deuteron Scattering

abstract:
  The general expressions for parity violation observables in elastic
scattering of polarized and/or unpolarized electrons from unpolarized deuterons
are given and are numerically evaluated for the kinematics of SAMPLE, PVA4 and
G0 experiments. The dominant contribution from the interference of $\gamma$ and
Z exchange as well as the smaller contributions from strangeness ($s{\bar{s}}$)
components of the nucleon, parity odd admixtures in the deuteron wave function,
anapole moments and radiative corrections are included and discussed in the
context of parity violating electron scattering experiments of present
interest.


title: Entropy of the FRW cosmology based on the brick wall method

abstract:
  The brick wall method in calculations of the entropy of black holes can be
applied to the FRW cosmology in order to study the statistical entropy. An
appropriate cutoff satisfying the covariant entropy bound can be chosen so that
the entropy has a definite bound. Among the entropy for each of cosmological
eras, the vacuum energy-dominated era turns out to give the maximal entropy
which is in fact compatible with assumptions from the brick wall method.


title:
Ballistic propagation of thermal excitations near a vortex in superfluid
  He3-B

abstract:
  Andreev scattering of thermal excitations is a powerful tool for studying
quantized vortices and turbulence in superfluid He3-B at very low temperatures.
We write Hamilton's equations for a quasiparticle in the presence of a vortex
line, determine its trajectory, and find under wich conditions it is Andreev
reflected. To make contact with experiments, we generalize our results to the
Onsager vortex gas, and find values of the intervortex spacing in agreement
with less rigorous estimates.


title:
Double-Lepton Polarization Asymmetries and Polarized Forward Backward
  Asymmetries in the Rare b \to s \ell^+ \ell^- Decays in a Single Universal
  Extra Dimension Scenario

abstract:
  We study the double-lepton polarization asymmetries and single and
double-lepton polarization forward backward asymmetries of the rare b \to s
\ell^+ \ell^- mode within the Standard Model and in the
Appelquist-Cheng-Dobrescu model, which is a new physics scenario with a single
universal extra dimension. In particular, we examine the sensitivity of the
observables to the radius R of the compactified extra-dimension, which is the
new parameter in this new physics model.


title: Conflations of Probability Distributions

abstract:
  The conflation of a finite number of probability distributions P_1,..., P_n
is a consolidation of those distributions into a single probability
distribution Q=Q(P_1,..., P_n), where intuitively Q is the conditional
distribution of independent random variables X_1,..., X_n with distributions
P_1,..., P_n, respectively, given that X_1= ... =X_n. Thus, in large classes of
distributions the conflation is the distribution determined by the normalized
product of the probability density or probability mass functions. Q is shown to
be the unique probability distribution that minimizes the loss of Shannon
Information in consolidating the combined information from P_1,..., P_n into a
single distribution Q, and also to be the optimal consolidation of the
distributions with respect to two minimax likelihood-ratio criteria. When
P_1,..., P_n are Gaussian, Q is Gaussian with mean the classical
weighted-mean-squares reciprocal of variances. A version of the classical
convolution theorem holds for conflations of a large class of a.c. measures.


title:
Observation of an Orbital Selective Electron-Mode Coupling in Fe-Based
  High-$T_c$ Superconductors

abstract:
  We have performed an angle-resolved photoemission spectroscopy study of the
new superconductor Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ in the low energy range. We
report the observation of an anomaly around 25 meV in the dispersion of
superconducting Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ samples that nearly vanishes
above $T_c$. The energy scale of the related mode (13$\pm$2 meV) and its strong
dependence on orbital and temperature indicates that it is unlikely related to
phonons. Moreover, the momentum locations of the kink can be connected by the
antiferromagnetic wavevector. Our results point towards an unconventional
electronic origin of the mode and the superconducting pairing in the Fe-based
superconductors, and strongly support the anti-phase s-wave pairing symmetry.


title:
In-gap state and effect of light illumination in CuIr$_2$S$_4$ probed by
  photoemission spectroscopy

abstract:
  We have studied disorder-induced in-gap states and effect of light
illumination in the insulating phase of spinel-type CuIr$_2$S$_4$ using
ultra-violet photoemission spectroscopy (UPS). The Ir$^{3+}$/Ir$^{4+}$
charge-ordered gap appears below the metal-insulator transition temperature.
However, in the insulating phase, in-gap spectral features with $softgap$ are
observed in UPS just below the Fermi level ($E_F$), corresponding to the
variable range hopping transport observed in resistivity. The spectral weight
at $E_F$ is not increased by light illumination, indicating that the
Ir$^{4+}$-Ir$^{4+}$ dimer is very robust although the long-range octamer order
would be destructed by the photo-excitation. Present results suggest that the
Ir$^{4+}$-Ir$^{4+}$ bipolaronic hopping and disorder effects are responsible
for the conductivity of CuIr$_2$S$_4$.


title:
The Cold Spot as a Large Void: Rees-Sciama effect on CMB Power Spectrum
  and Bispectrum

abstract:
  The detection of a "Cold Spot" in the CMB sky could be explained by the
presence of an anomalously large spherical underdense region (with radius of a
few hundreds Mpc/h) located between us and the Last Scattering Surface.
Modeling such an underdensity with an LTB metric, we investigate whether it
could produce significant signals on the CMB power spectrum and bispectrum, via
the Rees-Sciama effect. We find that this leads to a bump on the power
spectrum, that corresponds to an O(5%-25%) correction at multipoles 5 < l < 50;
in the cosmological fits, this would modify the \chi^2 by an amount of order
unity. We also find that the signal should be visible in the bispectrum
coefficients with a signal-to-noise S/N ~ O (1-10), localized at 10 < l < 40.
Such a signal would lead to an overestimation of the primordial f_{NL} by an
amount \Delta f_{NL} ~ 1 for WMAP and by \Delta f_{NL} ~ 0.1 for Planck.


title:
Near-Infrared Photometry and Radio Continuum Study of the Massive Star
  Forming Regions IRAS 21413+5442 and IRAS 21407+5441

abstract:
  IRAS 21413+5442 and IRAS 21407+5441 are two massive star forming regions of
high luminosity, likely associated with each other. Near-infrared photometry on
these two IRAS sources was performed at UKIRT using the UFTI under excellent
seeing conditions yielding an angular resolution of $\sim$ 0.5 arcsec. Our
results reveal details of stellar content to a completeness limit (90%) of J =
18.5, H = 18.0, and K = 17.5 mag in the two regions. In IRAS 21413+5442, we
identify a late O type star, having large (H-K) color, to be near the centre of
the CO jets observed by earlier authors. The UKIRT images reveal in IRAS
21407+5441, a faint but clear compact HII region around a central high -
intermediate mass star cluster. We have detected a number of sources with large
(H-K) color which are not detected in J band. We also present the GMRT radio
continuum map at 1.28 GHz covering the entire region surrounding the two star
forming clouds. The radio continuum fluxes are used to estimate the properties
of HII regions which seem to support our near-IR photometric results. Based on
our radio continuum map and the archival MSX 8.2 $\mu$m image, we show that the
two IRAS sources likely belong to the same parent molecular cloud and
conjecture that a high mass star of large IR colors, present in between the two
sources, might have triggered star formation in this region. However one can
not rule out the alternative possibility that Star A could be a nearby
foreground star.


title: Shellability and the strong gcd-condition

abstract:
  Shellability is a well-known combinatorial criterion for verifying that a
simplicial complex is Cohen-Macaulay. Another notion familiar to commutative
algebraists, but which has not received as much attention from
combinatorialists as the Cohen-Macaulay property, is the notion of a Golod
ring. Recently, a criterion on simplicial complexes reminiscent of
shellability, called the strong gcd-condition, was shown to imply Golodness of
the associated Stanley-Reisner ring. The two algebraic notions were tied
together by Herzog, Reiner and Welker who showed that if the Alexander dual of
a complex is sequentially Cohen-Macaulay then the complex itself is Golod. In
this paper, we present a combinatorial companion of this result, namely that if
the Alexander dual of a complex is (non-pure) shellable then the complex itself
satisfies the strong gcd-condition. Moreover, we show that all implications
just mentioned are strict in general but that they are equivalences for flag
complexes.


title: Computing with almost periodic functions

abstract:
  The paper develops a method for discrete computational Fourier analysis of
functions defined on quasicrystals and other almost periodic sets. A key point
is to build the analysis around the emerging theory of quasicrystals and
diffraction in the setting on local hulls and dynamical systems. Numerically
computed approximations arising in this way are built out of the Fourier module
of the quasicrystal in question, and approximate their target functions
uniformly on the entire infinite space.
  The methods are entirely group theoretical, being based on finite groups and
their duals, and they are practical and computable. Examples of functions based
on the standard Fibonacci quasicrystal serve to illustrate the method (which is
applicable to all quasicrystals modeled on the cut and project formalism).


title: Braneworld Models of Scalar Fields with Generalized Dynamics

abstract:
  This work deals with braneworld models driven by real scalar fields with
nonstandard dynamics. We develop the first-order formalism for models with
standard gravity but with the scalar fields having generalized dynamics. We
illustrate the results with examples of current interest, and we find
analytical and numerical solutions for warp factors and scalar fields. The
results indicate that the generalized braneworld scenario is classically
stable, and capable of localizing gravity


title:
Reduced fidelity susceptibility in the one-dimensional transverse field
  Ising model

abstract:
  We study critical behaviors of the reduced fidelity susceptibility for two
neighboring sites in the one-dimensional transverse field Ising model. It is
found that the divergent behaviors of the susceptibility take the form of
square of logarithm, in contrast with the global ground-state fidelity
susceptibility which is power divergence. In order to perform a scaling
analysis, we take the square root of the susceptibility and determine the
scaling exponent analytically and the result is further confirmed by numerical
calculations.