title:
Multifractal analysis of the metal-insulator transition in the 3D
  Anderson model II: Symmetry relation under ensemble averaging

abstract:
  We study the multifractal analysis (MFA) of electronic wavefunctions at the
localisation-delocalisation transition in the 3D Anderson model for very large
system sizes up to $240^3$. The singularity spectrum $f(\alpha)$ is numerically
obtained using the \textsl{ensemble average} of the scaling law for the
generalized inverse participation ratios $P_q$, employing box-size and
system-size scaling. The validity of a recently reported symmetry law [Phys.
Rev. Lett. 97, 046803 (2006)] for the multifractal spectrum is carefully
analysed at the metal-insulator transition (MIT). The results are compared to
those obtained using different approaches, in particular the typical average of
the scaling law. System-size scaling with ensemble average appears as the most
adequate method to carry out the numerical MFA. Some conjectures about the true
shape of $f(\alpha)$ in the thermodynamic limit are also made.


title: Disorder and the elusive superfluid phase of para-hydrogen

abstract:
  The possibility that disorder may stabilize a superfluid phase of
para-hydrogen in two dimensions is investigated theoretically by means of
Quantum Monte Carlo simulations. We model disorder using a random distribution
of scatterers, and study the thermodynamic behavior of the system as a function
of the scatterer density. Disorder gives rise to equilibrium glassy phases with
no superfluid properties. Indeed, the propensity for quantum exchanges of
hydrogen molecules is reduced even with respect to what is observed if the
scatterers are arranged as a regular crystal, a physical setting that also
yields no superfluidity.


title:
Constants of extended Standard Model and search for their temporal
  variations

abstract:
  Some methods for the determination and the most precise values of constants
of an extended Standard Model, which include the gravitation interaction and
massive neutrinos, are presented. Accuracies of constants at different energy
scales are compared and the possible manifestations of temporal variations of
constants are considered. Theoretical estimations and obtained experimental
bounds of variations are listed, that is important as for search of SM
generalizations as to account for possible influence on metrological
characteristics of measurement standards.


title: Ramsey interferometry with a spin embedded in a Coulomb chain

abstract:
  We show that the statistical properties of a Coulomb crystal can be measured
by means of a standard interferometric procedure performed on the spin of one
ion in the chain. The ion spin, constituted by two internal levels of the ion,
couples to the crystal modes via spatial displacement induced by photon
absorption. The loss of contrast in the interferometric signal allows one to
measure the autocorrelation function of the crystal observables. Close to the
critical point, where the chain undergoes a second-order phase transition to a
zigzag structure, the signal gives the behaviour of the correlation function at
the critical point.


title:
Mechanism of phase transitions and the electronic density of states in
  (La,Sm)FeAsO$_{1-x}$F$_x$ from ab initio calculations

abstract:
  The structure and electronic density of states in layered
LnFeAsO$_{1-x}$F$_x$ (Ln=La,Sm; $x$=0.0, 0.125, 0.25) are investigated using
density functional theory. For the $x$=0.0 system we predict a complex
potential energy surface, formed by close-lying single-well and double-well
potentials, which gives rise to the tetragonal-to-orthorhombic structural
transition, appearance of the magnetic order, and an anomaly in the specific
heat capacity observed experimentally at temperatures below $\sim$140--160 K.
We propose a mechanism for these transitions and suggest that these phenomena
are generic to all compounds containing FeAs layers. For $x>$0.0 we demonstrate
that transition temperatures to the superconducting state and their dependence
on $x$ correlate well with the calculated magnitude of the electronic density
of states at the Fermi energy.


title: Status of AKK Fragmentation Functions

abstract:
  We summarize the improvements to the previous AKK extraction of fragmentation
functions for pi^{+-}, K^{+-}, p/p-bar, K_S^0 and Lambda/Lambda-bar hadrons at
next-to-leading order implemented in the AKK08 sets.


title: Inclusive production of heavy-flavored hadrons at NLO in the GM-VFNS

abstract:
  We summarize recent progress in the theoretical description of
heavy-flavored-hadron inclusive production at next-to-leading order in the
general-mass variable-flavor-number scheme. Specifically, we discuss the
influence of finite-mass effects on the determination D-meson fragmentation
functions from a global fit to e^+e^- annihilation data and on the
transverse-momentum distribution of B-meson hadroproduction. We also
demonstrate that the fixed-flavor-number scheme, implemented with up-to-date
parton density functions and strong-coupling constant, provides a surprisingly
good description of B-meson data from run II at the Fermilab Tevatron.


title:
Photometric characterization of a well defined sample of isolated
  galaxies in the context of the AMIGA project

abstract:
  We perform a detailed photometric analysis (bulge-disk-bar decomposition and
Concentration-Asymmetry-Clumpiness - CAS parametrization) for a well defined
sample of isolated galaxies, extracted from the Catalog of Isolated Galaxies
(Karachentseva 1973) and reevaluated morphologically in the context of the
AMIGA project. We focus on Sb-Sc morphological types, as they are the most
representative population among the isolated spiral galaxies. Assuming that the
bulge Sersic index and/or Bulge/Total luminosity ratios are reasonable
diagnostics for pseudo- versus classical bulges, we conclude that the majority
of late-type isolated disk galaxies likely host pseudobulges rather than
classical bulges. Our parametrization of galactic bulges and disks suggests
that the properties of the pseudobulges are strongly connected to those of the
disks. This may indicate that pseudobulges are formed through internal
processes within the disks (i.e. secular evolution) and that bars may play an
important role in their formation. Although the sample under investigation
covers a narrow morphological range, a clear separation between Sb and Sbc-Sc
types is observed in various measures, e.g. the former are redder, brighter,
have larger disks and larger bars, more luminous bulges, are more concentrated,
more symmetric and clumpier than the latter. A comparison with samples of
spiral galaxies (within the same morphological range) selected without
isolation criteria reveals that the isolated galaxies tend to host larger bars,
are more symmetric, less concentrated and less clumpy.


title:
Multifractal analysis of the metal-insulator transition in the 3D
  Anderson model I: Symmetry relation under typical averaging

abstract:
  The multifractality of the critical eigenstate at the metal to insulator
transition (MIT) in the three-dimensional Anderson model of localization is
characterized by its associated singularity spectrum f(alpha). Recent works in
1D and 2D critical systems have suggested an exact symmetry relation in
f(alpha). Here we show the validity of the symmetry at the Anderson MIT with
high numerical accuracy and for very large system sizes. We discuss the
necessary statistical analysis that supports this conclusion. We have obtained
the f(alpha) from the box- and system-size scaling of the typical average of
the generalized inverse participation ratios. We show that the best symmetry in
f(alpha) for typical averaging is achieved by system-size scaling, following a
strategy that emphasizes using larger system sizes even if this necessitates
fewer disorder realizations.


title: Isometric Diamond Subgraphs

abstract:
  We describe polynomial time algorithms for determining whether an undirected
graph may be embedded in a distance-preserving way into the hexagonal tiling of
the plane, the diamond structure in three dimensions, or analogous structures
in higher dimensions. The graphs that may be embedded in this way form an
interesting subclass of the partial cubes.


title: On Certain Solutions for Confluent and Double-Confluent Heun Equations

abstract:
  This paper examines some solutions for confluent and double-confluent Heun
equations. In the first place, we review two Leaver's solutions in series of
regular and irregular confluent hypergeometric functions for the confluent
equation and introduce an additional expansion in series of irregular confluent
hypergeometric functions. Then, we find the conditions under which one of these
solutions can be written as a linear combination of the others. In the second
place, by means of limiting procedures we generate solutions for the
double-confluent equation as well as for special limits of both the confluent
and double-confluent equations. Finally, we present problems which are ruled by
each of these four equations and establish relations among Heun equations and
quasi-exactly solvable problems.


title: Quantum chromodynamics with advanced computing

abstract:
  We survey results in lattice quantum chromodynamics from groups in the USQCD
Collaboration. The main focus is on physics, but many aspects of the discussion
are aimed at an audience of computational physicists.


title: Anomalous Attenuation of Transverse Sound in 3He

abstract:
  We present the first measurements of the attenuation of transverse sound in
superfluid 3He-B. We use fixed path length interferometry combined with the
magneto-acoustic Faraday effect to vary the effective path length by a factor
of two, resulting in absolute values of the attenuation. We find that
attenuation is significantly larger than expected from the theoretical
dispersion relation, in contrast to the phase velocity of transverse sound. We
suggest that the anomalous attenuation can be explained by surface Andreev
bound states.


title:
Partition Functions of Three-Dimensional Quantum Gravity and the Black
  Hole Entropy

abstract:
  We analyze aspects of the holographic principle relevant to the quantum
gravity partition functions in Euclidean sector of AdS$_3$. The sum of the
known contributions to the partitions functions can be presented exactly,
including corrections, in the form where the Patterson-Selberg zeta function
involves.


title:
Superconductivity in SrFe_(2-x)Co_xAs_2: Internal Doping of the Iron
  Arsenide Layers

abstract:
  In the electron doped compounds SrFe_(2-x)Co_xAs_2 superconductivity with T_c
up to 20 K is observed for 0.2 < x < 0.4. Results of structure determination,
magnetic susceptibility, electrical resistivity, and specific heat are
reported. The observation of bulk superconductivity in all thermodynamic
properties -- despite strong disorder in the Fe-As layer -- favors an itinerant
picture in contrast to the cuprates and renders a p- or d-wave scenario
unlikely. DFT calculations find that the substitution of Fe by Co (x > 0.3)
leads to the suppression of the magnetic ordering present in SrFe_2As_2 due to
a rigid down-shift of the Fe-3d_(x^2-y^2) related band edge in the density of
states.


title:
Transverse spin relaxation time in organic molecules: A possible
  platform for fault tolerant room temperature quantum computing

abstract:
  We report measurement of the ensemble averaged transverse spin relaxation
time (T2*) in bulk and few molecules of the organic semiconductor
tris(8-hydroxyquinolinolato aluminum) or Alq3. This system exhibits two
characteristic T2* times, the longer of which is temperature-independent and
the shorter is temperature-dependent, indicating that the latter is most likely
limited by spin-phonon interaction. Based on the measured data, we infer that
the single particle T2 time is long enough to meet Knill's criterion for fault
tolerant quantum computing, even at room temperature. Alq3 is also an optically
active organic and we propose a simple optical scheme for spin qubit read out.
Moreover, we found that the temperature-dependent T2* time is considerably
shorter in bulk Alq3 powder than in few molecules confined in 1-2 nm sized
cavities, which is suggestive of a new type of ``phonon bottleneck effect''.
This is very intriguing for organic molecules where carriers are always
localized over individual molecules but the phonons are delocalized.


title:
XMM-Newton reveals the intrinsically X-ray weak nature of the quasar PG
  0043+039

abstract: This paper was withdrawn due to a misidentification of the source.


title: Strong Field Ionization Rate for Arbitrary Laser Frequencies

abstract:
  A simple, analytical, nonrelativistic ionization rate formula for atoms and
positive ions in intense ultraviolet and x-ray electromagnetic fields is
derived. The rate is valid at arbitrary values of the Keldysh parameter and
confirmed by results from ab initio numerical solutions of the single active
electron, time-dependent Schroedinger equation. The proposed rate is
particularly relevant for experiments employing the new free electron laser
(FEL) sources under construction worldwide.


title:
Nonoscillation and Stability of the Second Order Ordinary Differential
  Equations with a Damping Term

abstract:
  In this paper we consider the linear ordinary equation of the second order $$
L x(t)\equiv \ddot{x}(t) +a(t)\dot{x}(t)+b(t)x(t)=f(t), \eqno{(1)} $$ and the
corresponding homogeneous equation $$ \ddot{x}(t) +a(t)\dot{x}(t)+b(t)x(t)=0.
\eqno{(2)} $$ Note that $[\alpha ,\beta ]$ is called a nonoscillation interval
if every nontrivial solution has at most one zero on this interval. Many
investigations which seem to have no connection such as differential
inequalities, the Polia-Mammana decomposition (i.e. representation of the
operator $L$ in the form of products of the first order differential
operators), unique solvability of the interpolation problems, kernels
oscillation, separation of zeros, zones of Lyapunov's stability and some others
have a certain common basis - nonoscillation. Presumably Sturm was the first to
consider the two problems which naturally appear here: to develop corollaries
of nonoscillation and to find methods to check nonoscillation. In this paper we
obtain several tests for nonoscillation on the semiaxis and apply them to
propose new results on asymptotic properties and the exponential stability of
the second order equation (2). Using the Floquet representations and upper and
lower estimates of nonoscillation intervals of oscillatory solutions we deduce
results on the exponential and Lyapunov's stability and instability of equation
(2).


title: Structure and superconductivity of LiFeAs

abstract:
  The lithium ions in Lithium iron arsenide phases with compositions close to
LiFeAs have been located using powder neutron diffraction. These phases exhibit
superconductivity at temperatures at least as high as 16 K demonstrating that
superconductivity in compounds with [FeAs]- anti-PbO-type anionic layers occurs
in compounds with at least three different structure types and occurs for a
wide range of As-Fe-As bond angles.


title: The inequality of charge and spin diffusion coefficients

abstract:
  Since spin and charge are both carried by electrons (or holes) in a solid, it
is natural to assume that charge and spin diffusion coefficients will be the
same. Drift-diffusion models of spin transport typically assume so. Here, we
show analytically that the two diffusion coefficients can be vastly different
in quantum wires. Although we do not consider quantum wells or bulk systems, it
is likely that the two coefficients will be different in those systems as well.
Thus, it is important to distinguish between them in transport models,
particularly those applied to quantum wire based devices


title:
Tracing jet--ISM interaction in young AGN: correlations between [OIII]
  5007 and 5-GHz emission

abstract:
  *AIMS: To study the interaction between young AGN and their host galaxies
based on their ionized gas and radio emission, and to analyze possible
implications for the radio galaxy evolution.
  *METHODS: The [OIII] 5007 line and 5-GHz radio properties are compared and
studied on a large, representative sample of GPS and CSS (i.e., young) quasars
and radio galaxies as well as large-scale sources using [OIII] 5007 line and
5-GHz radio data from literature and our observations.
  *RESULTS: Several correlations between the [OIII] 5007 line and 5-GHz radio
emission have been found. The main result is that the [OIII] 5007 emission is
strongly related to the GPS/CSS source size indicating that the [OIII] 5007
emission is clearly enhanced by the jet expansion through the host galaxy ISM.
Shocks are the most likely enhancing mechanism, although jet-induced star
formation could also be, partly, responsible for the [OIII] 5007 emission. The
data also suggests a possible deceleration of the jet as it grows. In this
case, however, the correlation is weak.


title:
Hausdorff dimension for ergodic measures of interval exchange
  transformations

abstract:
  I show that there exist minimal interval exchange transformations with an
ergodic measure whose Hausdorff dimension is arbitrarily small, even 0. I will
also show that in particular cases one can bound the Hausdorff dimension
between $\frac 1 {2r+4}$ and $\frac 1 r$ for any r greater than 1.


title:
Nondegenerate parametric down conversion in coherently prepared
  two-level atomic gas

abstract:
  We describe parametric down conversion process in a two-level atomic gas,
where the atoms are in a superposition state of relevant energy levels. This
superposition results in splitting of the phase matching condition into three
different conditions. Another, more important, peculiarity of the system under
discussion is the nonsaturability of amplification coefficients with increasing
pump wave intensity, under "sideband" generation conditions.


title:
Aspects of area formulas by way of Luzin, Rad\'o, and Reichelderfer on
  metric measure spaces

abstract:
  We consider some measure-theoretic properties of functions belonging to a
Sobolev-type class on metric measure spaces that admit a Poincar\'e inequality
and are equipped with a doubling measure. The properties we have selected to
study are those that are related to area formulas.


title: Quantum cryptography using partially entangled states

abstract:
  We show that non-maximally entangled states can be used to build a quantum
key distribution (QKD) scheme whose security and key rate transmission is
nearly equivalent to those of standard QKD protocols. These aspects can be
controlled by using the new free parameter in the present scheme, namely, the
degree of partial entanglement. Furthermore, we discuss how to build a
controlled QKD scheme, also based on partially entangled states, where a third
party can decide whether or not Alice and Bob are allowed to share a key.


title: Conical Di-jet Correlations from a Chromo-Viscous Neck in AdS/CFT

abstract:
  We show that Mach-like correlations from heavy quark jets in the Gubser et al
AdS/CFT string drag model arise not from the expected (weak) hydrodynamical
Mach sound wakes zone but from a near ``Neck'' zone where strong chromo-viscous
field effects dominated and lead to a distinctive stress in the plasma of the
form $T^{\mu\nu}_{Neck} \propto \surd \lambda T_0^2 Y^{\mu\nu}(x)/x^2$. We
propose that measurement of the jet velocity dependence of moderate $p_T$
hadrons associated with future {\em identified heavy quark jets} at RHIC and
LHC could be used to look for this novel source of conical correlations which
are unrelated to Mach's law.


title:
The ruggedness of protein-protein energy landscape and the cutoff for
  1/r^n potentials

abstract:
  The interaction cutoff contribution to the ruggedness of protein-protein
energy landscape (the artificial ruggedness) is studied in terms of relative
energy fluctuations for 1/r^n potentials based on a simplistic model of a
protein complex. Contradicting the principle of minimal frustration, the
artificial ruggedness exists for short cutoffs and gradually disappears with
the cutoff increase. The critical values of the cutoff were calculated for each
of eleven popular power-type potentials with n=0-9, 12 and for two thresholds
of 5% and 10%. The artificial ruggedness decreases to tolerable thresholds for
cutoffs longer than the critical ones. The results showed that for both
thresholds the critical cutoff is a non-monotonic function of the potential
power n. The functions reach the maximum at n=3-4 and then decrease with the
increase of the potential power. The difference between two cutoffs for 5% and
10% artificial ruggedness becomes negligible for potentials decreasing faster
than 1/r^12. The results suggest that cutoffs longer than critical ones can be
recommended for protein-protein potentials.


title: Superconductivity at 22 K in Co-doped BaFe2As2 Crystals

abstract:
  Here we report bulk superconductivity in BaFe1.8Co0.2As2 single crystals
below Tc = 22 K, as demonstrated by resistivity, magnetic susceptibility, and
specific heat data. Hall data indicate that the dominant carriers are
electrons, as expected from simple chemical reasoning. This is the first
example of superconductivity induced by electron doping in this family of
materials. In contrast to the cuprates, the BaFe2As2 system appears to tolerate
considerable disorder in the FeAs planes. First principles calculations for
BaFe1.8Co0.2As2 indicate the inter-band scattering due to Co is weak.


title: Comparison of cobordism theories

abstract:
  Relying on results of Hopkins-Morel, we show that, for $X$ a quasi-projective
variety over a field of characteristic zero, the canonical map $\Omega_n(X)\to
MGL_{2n,n}'(X)$ is an isomorphism. Here $\Omega_*(X)$ is the theory of
algebraic cobordism defined by Levine-Morel, and $MGL_{*,*}'$ is the
Borel-Moore homology version of the theory of algebraic cobordism defined via
the algebraic Thom complex in the Morel-Voevodsky motivic stable homotopy
category.


title: Origin of the S Stars in the Galactic Center

abstract:
  Over the last 15 years, around a hundred very young stars have been observed
in the central parsec of our Galaxy. While the presence of young stars forming
one or two stellar disks at approx. 0.1 pc from the supermassive black hole
(SMBH) can be understood through star formation in accretion disks, the origin
of the S stars observed a factor of 10 closer to the SMBH has remained a major
puzzle. Here we show the S stars to be a natural consequence of dynamical
interaction of two stellar disks at larger radii. Due to precession and Kozai
interaction, individual stars achieve extremely high eccentricities at random
orientation. Stellar binaries on such eccentric orbits are disrupted due to
close passages near the SMBH, leaving behind a single S star on a much tighter
orbit. The remaining star may be ejected from the vicinity of the SMBH, thus
simultaneously providing an explanation for the observed hypervelocity stars in
the Milky Way halo.


title: X-ray selected AGN in groups at redshifts z~1

abstract:
  We explore the role of the group environment in the evolution of AGN at the
redshift interval 0.7<z<1.4, by combining deep Chandra observations with
extensive optical spectroscopy from the All-wavelength Extended Groth strip
International Survey (AEGIS). The sample consists of 3902 optical sources and
71 X-ray AGN. Compared to the overall optically selected galaxy population,
X-ray AGN are more frequently found in groups at the 99% confidence level. This
is partly because AGN are hosted by red luminous galaxies, which are known to
reside, on average, in dense environments. Relative to these sources, the
excess of X-ray AGN in groups is significant at the 91% level only. Restricting
the sample to 0.7<z<0.9 and M_B<-20mag in order to control systematics we find
that X-ray AGN represent (4.7\pm1.6) and (4.5\pm1.0)% of the optical galaxy
population in groups and in the field respectively. These numbers are
consistent with the AGN fraction in low redshift clusters, groups and the
field. The results above, although affected by small number statistics, suggest
that X-ray AGN are spread over a range of environments, from groups to the
field, once the properties of their hosts (e.g. colour, luminosity) are
accounted for. There is also tentative evidence, significant at the 98% level,
that the field produces more X-ray luminous AGN compared to groups, extending
similar results at low redshift to z~1. This trend may be because of either
cold gas availability or the nature of the interactions occurring in the denser
group environment (i.e. prolonged tidal encounters).


title:
Spitzer Observations of Bok Globule B335: Isolated Star Formation
  Efficiency and Cloud Structure

abstract:
  We present infrared and millimeter observations of Barnard 335, the
prototypical isolated Bok globule with an embedded protostar. Using Spitzer
data we measure the source luminosity accurately; we also constrain the density
profile of the innermost globule material near the protostar using the
observation of an 8.0 um shadow. HHT observations of 12CO 2 --> 1 confirm the
detection of a flattened molecular core with diameter ~10000 AU and the same
orientation as the circumstellar disk (~100 to 200 AU in diameter). This
structure is probably the same as that generating the 8.0 um shadow and is
expected from theoretical simulations of collapsing embedded protostars. We
estimate the mass of the protostar to be only ~5% of the mass of the parent
globule.


title:
Bayesian analysis of sparse anisotropic universe models and application
  to the 5-yr WMAP data

abstract:
  We extend the previously described CMB Gibbs sampling framework to allow for
exact Bayesian analysis of anisotropic universe models, and apply this method
to the 5-year WMAP temperature observations. This involves adding support for
non-diagonal signal covariance matrices, and implementing a general spectral
parameter MCMC sampler. As a worked example we apply these techniques to the
model recently introduced by Ackerman et al., describing for instance
violations of rotational invariance during the inflationary epoch. After
verifying the code with simulated data, we analyze the foreground-reduced
5-year WMAP temperature sky maps. For l <= 400 and the W-band data, we find
tentative evidence for a preferred direction pointing towards (l,b) = (110 deg,
10 deg) with an anisotropy amplitude of g_* = 0.15 +/- 0.039. Similar results
are obtained from the V-band data [g_* = 0.10 +/- 0.04; (l,b) = (130 deg, 20
deg)]. Further, the preferred direction is stable with respect to multipole
range, seen independently in both l=[2,100] and [100,400], although at lower
statistical significance. We have not yet been able to establish a fully
satisfactory explanation for the observations in terms of known systematics,
such as non-cosmological foregrounds, correlated noise or asymmetric beams, but
stress that further study of all these issues is warranted before a
cosmological interpretation can be supported.


title:
The Physical Scale of the Far-Infrared Emission in the Most Luminous
  Submillimeter Galaxies

abstract:
  We present high resolution submillimeter interferometric imaging of two of
the brightest high-redshift submillimeter galaxies known: GN20 and AzTEC1 at
0.8 and 0.3 arcsec resolution respectively. Our data - the highest resolution
submillimeter imaging of high redshift sources accomplished to date - was
collected in three different array configurations: compact, extended, and very
extended. We derive angular sizes of 0.6 and 1.0 arcsec for GN20 and 0.3 and
0.4 arcsec for AzTEC1 from modeling their visibility functions as a Gaussian
and elliptical disk respectively. Because both sources are B-band dropouts,
they likely lie within a relatively narrow redshift window around z~4, which
indicates their angular extent corresponds to physical scales of 4-8 and 1.5-3
kpc respectively for the starburst region. By way of a series of simple
assumptions, we find preliminary evidence that these hyperluminous starbursts -
with star formation rates >1000 $M_\odot$ yr$^{-1}$ - are radiating at or close
to their Eddington limit. Should future high resolution observations indicate
that these two objects are typical of a population of high redshift
Eddington-limited starbursts, this could have important consequences for models
of star formation and feedback in extreme environments.


title: Dark Matter and LHC: What is the Connection?

abstract:
  We review what can (and cannot) be learned if dark matter is detected in one
or more experiments, emphasizing the importance of combining LHC data with
direct, astrophysical and cosmological probes of dark matter. We briefly review
the conventional picture of a thermally produced WIMP relic density and its
connection with theories of electroweak symmetry breaking. We then discuss both
experimental and theoretical reasons why one might generically expect this
picture to fail. If this is the case, we argue that a combined effort bringing
together all types of data -- combined with explicitly constructed theoretical
models -- will be the only way to achieve a complete understanding of the dark
matter in our universe and become confident that any candidate actually
provides the relic density.


title: Nemirovski's Inequalities Revisited

abstract:
  An important tool for statistical research are moment inequalities for sums
of independent random vectors. Nemirovski and coworkers (1983, 2000) derived
one particular type of such inequalities: For certain Banach spaces
$(\B,\|\cdot\|)$ there exists a constant $K = K(\B,\|\cdot\|)$ such that for
arbitrary independent and centered random vectors $X_1, X_2, ..., X_n \in \B$,
their sum $S_n$ satisfies the inequality $ E \|S_n \|^2 \le K \sum_{i=1}^n E
\|X_i\|^2$. We present and compare three different approaches to obtain such
inequalities: Nemirovski's results are based on deterministic inequalities for
norms. Another possible vehicle are type and cotype inequalities, a tool from
probability theory on Banach spaces. Finally, we use a truncation argument plus
Bernstein's inequality to obtain another version of the moment inequality
above. Interestingly, all three approaches have their own merits.


title: Entropy Functions with 5D Chern-Simons terms

abstract:
  In this note we reconsider Sen's entropy function analysis for 5D
supergravity actions containing Chern-Simons terms. The apparent lack of gauge
invariance is usually tackled via a 4D reduction. Here we motivate how a
systematic 5D procedure also works. In doing so, it becomes important to
identify the correct 5D charges. In particular, we perform explicit
calculations for the black ring and 5D black hole. In the black ring analysis,
we find Chern-Simons induced spectral flow shifts emerging out of Sen's
formalism. We find that the entropy function nevertheless remains gauge
invariant and the resulting electric charges are identified as Page charges.
For the black hole too, 5D gauge invariance is confirmed. Our 5D analysis
enables us to fix a mismatch that arose in the electric charges of Goldstein
and Jena's 4D-reduced calculation. Finally we provide an interpretation for the
e^0 - p^0 exchange in the entropy function as an interpolation between black
hole and black ring geometries in Taub-NUT.


title:
Adittional levels between Landau bands due to vacancies in graphene:
  towards a defect engineering

abstract:
  We describe the effects of vacancies on the electronic properties of a
graphene sheet in the presence of a perpendicular magnetic field: from a single
defect to an organized vacancy lattice. An isolated vacancy is the minimal
possible inner edge, showing an antidotlike behaviour, which results in an
extra level between consecutive Landau levels. Two close vacancies may couple
to each other, forming a vacancy molecule tuned by the magnetic field. We show
that a vacancy lattice introduce an extra band in between Landau levels with
localization properties that could lead to extra Hall resistance plateaus.


title: Tight-binding theory of lanthanum strontium manganate

abstract:
  An earlier analysis of manganese oxides in various charge states indicated
that free-atom term values and universal coupling gave a reasonable account of
the cohesion. This approach is here extended to LaxSr(1-x)MnO3 in a perovskite
structure, and a wide range of properties, with comparable success, including
the cohesion, as a function of x. Magnetic and electronic properties are
treated in terms of the same parameters and the cluster orbitals used for
cohesion. This includes an estimate of the Neel and Curie-Weiss temperatures
for SrMnO3, an antiferromagnetic insulator, and the magnitude of a Jahn-Teller
distortion in LaMnO3 which makes it also insulating with (100) ferromagnetic
planes (due to a novel double-exchange for the distorted state),
antiferromagnetically stacked, as observed. We estimate the Neel temperature
and its volume dependence, and the ferromagnetic Curie-Weiss temperature which
applies between the Neel and Jahn-Teller temperatures. We expect hopping
conductivity when there is doping (0<x<1) and estimate it in the context of
small-polaron theory. It is in accord with experiment between the Neel and
Jahn-Teller temperatures, but below the Neel temperature the conduction appears
to be band-like, for which we estimate a hole mass as enhanced in large-polaron
theory. We see that above the Jahn-Teller temperature LaMnO3 should be metallic
as observed, and paramagnetic with a ferromagnetic Curie-Weiss constant which
we estimate. Many of these predictions are not so accurate, but are
sufficiently close to provide a clear understanding of all of these properties
in terms of a simple theory and parameters known at the outset. We provide also
these parameters for Fe, Co, and Ca so that formulae for the properties can
readily be evaluated for similar systems.


title:
Mathematical Analysis of a Kinetic Model for Cell Movement in Network
  Tissues

abstract:
  Mesenchymal motion describes the movement of cells in biological tissues
formed by fiber networks. An important example is the migration of tumor cells
through collagen networks during the process of metastasis formation. We
investigate the mesenchymal motion model proposed by T. Hillen (J. Math. Biol.
53:585-616, 2006) in higher dimensions. We formulate the problem as an
evolution equation in a Banach space of measure-valued functions and use
methods from semigroup theory to show the global existence of classical
solutions. We investigate steady states of the model and show that patterns of
network type exist as steady states. For the case of constant fiber
distribution, we find an explicit solution and we prove the convergence to the
parabolic limit.


title: Inelastic Dark Matter in Light of DAMA/LIBRA

abstract:
  Inelastic dark matter, in which WIMP-nucleus scatterings occur through a
transition to an excited WIMP state ~ 100 keV above the ground state, provides
a compelling explanation of the DAMA annual modulation signal. We demonstrate
that the relative sensitivities of various dark matter direct detection
experiments are modified such that the DAMA annual modulation signal can be
reconciled with the absence of a reported signal at CDMS-Soudan, XENON10,
ZEPLIN, CRESST, and KIMS for inelastic WIMPs with masses O(100 GeV). We review
the status of these experiments, and make predictions for upcoming ones. In
particular, we note that inelastic dark matter leads to highly suppressed
signals at low energy, with most events typically occurring between 20 to 45
keV (unquenched) at xenon and iodine experiments, and generally no events at
low (~ 10 keV) energies. Suppressing the background in this high energy region
is essential to testing this scenario. The recent CRESST data suggest seven
observed tungsten events, which is consistent with expectations from this
model. If the tungsten signal persists at future CRESST runs, it would provide
compelling evidence for inelastic dark matter, while its absence should exclude
it.


title: On the duration of long GRBs: effects of black hole spin

abstract:
  In the frame of the collapsar model for long gamma ray bursts (GRBs), we
investigate the formation of a torus around a spinning BH and we check what
rotational properties a progenitor star must have in order to sustain torus
accretion over relatively long activity periods. We also study the time
evolution of the BH spin parameter. We take into account the coupling between
BH mass, its spin parameter and the critical specific angular momentum of
accreting gas, needed for the torus to form. The large BH spin reduces the
critical angular momentum which in turn can increase the GRB duration with
respect to the Schwarzschild BH case. We quantify this effect and estimate the
GRB durations in three cases: when a hyper accreting torus operates or a BH
spins very fast or both. We show under what conditions a given progenitor star
produces a burst that can last as short as several seconds and as long as
several hundred of seconds. Our models indicate that it is possible for a
single collapse to produce three kinds of jets: (1) a very short, lasting
between a fraction of a second and a few seconds, 'precursor' jet, powered only
by a hyper accreting torus before the BH spins up, (2) an 'early' jet, lasting
several tens of seconds and powered by both hyper accretion and BH rotation,
and (3) a 'late' jet, powered only by the spinning BH.


title: Medium Modifications from 4He(e,e'p)3H

abstract:
  Polarization transfer in quasi-elastic nucleon knockout is sensitive to the
properties of the nucleon in the nuclear medium, including possible
modification of the nucleon form factor and/or spinor. In our recently
completed experiment E03-104 at Jefferson Lab we measured the proton recoil
polarization in the 4He(e,e'p)3H reaction at a Q^2 of 0.8 (GeV/c)^2 and 1.3
(GeV/c)^2 with unprecedented precision. These data complement earlier data
between 0.4 and 2.6 (GeV/c)^2 from both Mainz and Jefferson Lab. The measured
ratio of polarization-transfer coefficients differs from a fully relativistic
calculation, favoring either the inclusion of a medium modification of the
proton form factors predicted by a quark-meson coupling model or strong
charge-exchange final-state interactions. The measured induced polarizations
agree well with the fully relativistic calculation and indicate that these
strong final-state interactions may not be applicable.


title: Patterns of variability in gamma-ray blazars

abstract:
  Preliminary results of a systematic study on the simultaneous
optical-to-X-rays variability in blazars are presented. Data from Swift
observations of four bright gamma-ray blazars (3C 279, ON+231, S5 0716+71, PKS
2155-304) have been analyzed, compared, and discussed. Specifically, 3C 279
shows a variable flattening in the low energy part of the X-ray spectrum that
appears to be confined in a specific X-ray vs optical/UV fluxes region. Some
implications are shortly analyzed.


title:
The Inhomogeneous Background of Hydrogen-Molecule Dissociating Radiation
  during Cosmic Reionization

abstract:
  The first, self-consistent calculations are presented of the cosmological,
H2-dissociating UV background produced during the epoch of reionization by the
sources of reionization. Large-scale radiative transfer simulations of
reionization trace the impact of all the ionizing starlight on the IGM from all
the sources in our simulation volume down to dwarf galaxies of mass ~10^8 Msun,
identified by very high-resolution N-body simulations, including the
self-regulating effect of IGM photoheating on dwarf galaxy formation. The UV
continuum emitted below 13.6 eV by each source is then transferred through the
same IGM, attenuated by atomic H Lyman series resonance lines, to predict the
evolution of the inhomogeneous radiation background in the Lyman-Werner bands
of H2 between 11 and 13.6 eV. On average, the intensity of this Lyman-Werner
background is found to rise to the threshold level at which dissociation
suppresses H2 cooling and star formation inside minihalos, long before
reionization is complete. Spatial variations in the Lyman-Werner background are
found which result from the clustering of sources associated with large-scale
structure formation, such that intensity fluctuations correlate with matter
density fluctuations. As a result, the Lyman-Werner background rises to the
threshold level for H2 suppression earlier in the vicinity of the reionization
sources and their H II regions.


title: The Submillimeter Array Polarimeter

abstract:
  We describe the Submillimeter Array (SMA) Polarimeter, a polarization
converter and feed multiplexer installed on the SMA. The polarimeter uses
narrow-band quarter-wave plates to generate circular polarization sensitivity
from the linearly-polarized SMA feeds. The wave plates are mounted in rotation
stages under computer control so that the polarization handedness of each
antenna is rapidly selectable. Positioning of the wave plates is found to be
highly repeatable, better than 0.2 degrees. Although only a single polarization
is detected at any time, all four cross correlations of left- and
right-circular polarization are efficiently sampled on each baseline through
coordinated switching of the antenna polarizations in Walsh function patterns.
The initial set of anti-reflection coated quartz and sapphire wave plates
allows polarimetry near 345 GHz; these plates have been have been used in
observations between 325 and 350 GHz. The frequency-dependent
cross-polarization of each antenna, largely due to the variation with frequency
of the retardation phase of the single-element wave plates, can be measured
precisely through observations of bright point sources. Such measurements
indicate that the cross-polarization of each antenna is a few percent or
smaller and stable, consistent with the expected frequency dependence and very
small alignment errors. The polarimeter is now available for general use as a
facility instrument of the SMA.


title: A study of the Forbush decrease event of September 11, 2005 with GRAND

abstract:
  Project GRAND, a proportional wire chamber array, is used to examine the
decreased counting rate of ground level muons during the Forbush decrease event
of September 11, 2005. Data are presented and compared to that of other cosmic
ray monitors. A directional study of the Forbush decrease was undertaken and
precursor anisotropies to this geomagnetic storm were studied utilizing GRAND's
angular resolution.


title: Oriented cohomology, Borel-Moore homology and algebraic cobordism

abstract:
  We examine various versions of oriented cohomology and Borel-Moore homology
theories in algebraic geometry and put these two together in the setting of an
"oriented duality theory", a generalization of Bloch-Ogus twisted duality
theory. This combines and exends work of Panin and Mocanasu. We apply this to
give a Borel-Moore homology version $MGL'_{*,*}$ of Voevodsky's
$MGL^{*,*}$-theory, and a natural map $\vartheta:\Omega_*\to MGL'_{2*,*}$,
where $\Omega_*$ is the algebraic cobordism theory defined by Levine-Morel. We
conjecture that $\vartheta$ is an isomorphism and describe a program for
proving this conjecture.


title: Status report on project GRAND

abstract:
  GRAND is an array of position sensitive proportional wire chambers (PWCs)
located at 86.2 degrees W, 41.7 degrees N at an elevation of 220 m adjacent to
the campus of the University of Notre Dame with 82 square meters of total muon
detector area. The geometry of the PWCs allows the angles of the charged
secondary muon tracks to be measured to +/- 0.3 deg in each of two orthogonal
planes. Muons are 99% differentiated from electrons by means of a 51 mm steel
plate in each detector.


title:
Modified Higgs Boson Phenomenology from Gauge or Gaugino Mediation in
  the NMSSM

abstract:
  In the Next-to-Minimal Supersymmetric Standard Model (NMSSM), the presence of
light pseudoscalars can have a dramatic effect on the decays of the Standard
Model-like Higgs boson. These pseudoscalars are naturally light if
supersymmetry breaking preserves an approximate U(1)_R symmetry, spontaneously
broken when the Higgs bosons take on their expectation values. We investigate
two classes of theories that possess such an approximate U(1)_R at the
mediation scale: deformations of gauge and gaugino mediation. In the models we
consider, we find two disjoint classes of phenomenologically allowed parameter
regions. One of these regions corresponds to a limit where the singlet of the
NMSSM largely decouples. The other can give rise to a Standard Model-like Higgs
boson with a dominant branching into light pseudoscalars.


title: A new method to detect the vortex glass phase and its evidence in YBCO

abstract:
  The Vortex Glass phase has been unequivocally identified by analyzing the non
linear magnetic response of type II superconductors. The method here
introduced, more effective than the study of direct transport measurements, is
based on a combined frequency dependence analysis of the real and imaginary
part of the 1st and 3rd harmonics of the AC magnetic susceptibility. The
analysis has been performed by taking into account both the components and the
Cole-Cole plots (i.e. the imaginary part as a function of the real part).
Numerical simulations have been used to individuate the fingerprints of the
magnetic behaviour in the Vortex Glass phase. These characteristics allowed to
distinguish the Vortex Glass phase from the other disordered phases, even those
showing similar electrical properties. Finally, this method has been
successfully applied to detect the Vortex Glass Phase in an YBCO bulk
melt-textured sample.


title: Gravitational radiation in d>4 from effective field theory

abstract:
  Some years ago, a new powerful technique, known as the Classical Effective
Field Theory, was proposed to describe classical phenomena in gravitational
systems. Here we show how this approach can be useful to investigate
theoretically important issues, such as gravitational radiation in any
spacetime dimension. In particular, we derive for the first time the
Einstein-Infeld-Hoffman Lagrangian and we compute Einstein's quadrupole formula
for any number of flat spacetime dimensions.


title:
Simulating polarized Galactic synchrotron emission at all frequencies,
  the Hammurabi code

abstract:
  We present a publicly available code called Hammurabi for generating mock
polarized observations of Galactic synchrotron emission for telescopes like
LOFAR, SKA, Planck and WMAP, based on model inputs for the Galactic magnetic
field (GMF), the cosmic-ray density distribution and the thermal electron
density. We also present mock UHECR deflection measure (UDM) maps based on
model inputs for the GMF. In future, when UHECR sources are identified, this
will allow us to define UDM as a GMF probe in a similar way as polarized radio
sources permit us to define rotation measures. To demonstrate the code's
abilities mock observations are compared to real data as a means to constrain
the input parameters of our simulations with a focus on large-scale magnetic
field properties. As expected, attempts at trying to model the synchrotron,
UHECR deflection and RM input parameters, show that any additional
observational data set greatly increases the constraints on the models. The
hammurabi code addresses this by allowing to perform simulations of several
different data sets simultaneously, providing the means for a more reliable
constraint of the magnetized inter-stellar-medium.


title: One-dimensional quantum random walks with two entangled coins

abstract:
  We offer theoretical explanations for some recent observations in numerical
simulations of quantum random walks (QRW). Specifically, in the case of a QRW
on the line with one particle (walker) and two entangled coins, we explain the
phenomenon, called "localization", whereby the probability distribution of the
walker's position is seen to exhibit a persistent major "spike" (or "peak") at
the initial position and two other minor spikes which drift to infinity in
either direction. Another interesting finding in connection with QRW's of this
sort pertains to the limiting behavior of the position probability
distribution. It is seen that the probability of finding the walker at any
given location becomes eventually stationary and non-vanishing. We explain
these observations in terms of the degeneration of some eigenvalue of the time
evolution operator $U(k)$. An explicit general formula is derived for the
limiting probability, from which we deduce the limiting value of the height of
the observed spike at the origin. We show that the limiting probability
decreases {\em quadratically} for large values of the position $x$. We locate
the two minor spikes and demonstrate that their positions are determined by the
phases of non-degenerated eigenvalues of $U(k)$. Finally, for fixed time $t$
sufficiently large, we examine the dependence on $t$ of the probability of
finding a particle at a given location $x$.


title:
Rate of Escape of Random Walks on Regular Languages and Free Products by
  Amalgamation of Finite Groups

abstract:
  We consider random walks on the set of all words over a finite alphabet such
that in each step only the last two letters of the current word may be modified
and only one letter may be adjoined or deleted. We assume that the transition
probabilities depend only on the last two letters of the current word.
Furthermore, we consider also the special case of random walks on free products
by amalgamation of finite groups which arise in a natural way from random walks
on the single factors. The aim of this paper is to compute several equivalent
formulas for the rate of escape with respect to natural length functions for
these random walks using different techniques.


title: Smooth motives

abstract:
  Following ideas of Bondarko, we construct a DG category whose homotopy
category is equivalent to the full subcategory of motives over a base-scheme
$S$ generated by the motives of smooth projective $S$-schemes, assuming that
$S$ is itself smooth over a perfect field.


title: Algebraic Birkhoff decomposition and its applications

abstract:
  Central in the Hopf algebra approach to the renormalization of perturbative
quantum field theory of Connes and Kreimer is their Algebraic Birkhoff
Decomposition. In this tutorial article, we introduce their decomposition and
prove it by the Atkinson Factorization in Rota-Baxter algebra. We then give
some applications of this decomposition in the study of divergent integrals and
multiple zeta values.


title:
Structure theorems of mixable shuffle algebras and free commutative
  Rota-Baxter algebras

abstract:
  We study the ring theoretical structures of mixable shuffle algebras and
their associated free commutative Rota-Baxter algebras. For this study we
utilize the connection of the mixable shuffle algebras with the overlapping
shuffle algebra of Hazewinkel, quasi-shuffle algebras of Hoffman and
quasi-symmetric functions. This connection allows us to apply methods and
results on shuffle products and Lyndon words on ordered sets. As a result, we
obtain structure theorems for a large class of mixable shuffle algebras and
free commutative Rota-Baxter algebras with various coefficient rings.


title:
Multihop Diversity in Wideband OFDM Systems: The Impact of Spatial Reuse
  and Frequency Selectivity

abstract:
  The goal of this paper is to establish which practical routing schemes for
wireless networks are most suitable for wideband systems in the power-limited
regime, which is, for example, a practically relevant mode of operation for the
analysis of ultrawideband (UWB) mesh networks. For this purpose, we study the
tradeoff between energy efficiency and spectral efficiency (known as the
power-bandwidth tradeoff) in a wideband linear multihop network in which
transmissions employ orthogonal frequency-division multiplexing (OFDM)
modulation and are affected by quasi-static, frequency-selective fading.
Considering open-loop (fixed-rate) and closed-loop (rate-adaptive) multihop
relaying techniques, we characterize the impact of routing with spatial reuse
on the statistical properties of the end-to-end conditional mutual information
(conditioned on the specific values of the channel fading parameters and
therefore treated as a random variable) and on the energy and spectral
efficiency measures of the wideband regime. Our analysis particularly deals
with the convergence of these end-to-end performance measures in the case of
large number of hops, i.e., the phenomenon first observed in \cite{Oyman06b}
and named as ``multihop diversity''. Our results demonstrate the realizability
of the multihop diversity advantages in the case of routing with spatial reuse
for wideband OFDM systems under wireless channel effects such as path-loss and
quasi-static frequency-selective multipath fading.


title:
An Efficient Algorithm for a Sharp Approximation of Universally
  Quantified Inequalities

abstract:
  This paper introduces a new algorithm for solving a sub-class of quantified
constraint satisfaction problems (QCSP) where existential quantifiers precede
universally quantified inequalities on continuous domains. This class of QCSPs
has numerous applications in engineering and design. We propose here a new
generic branch and prune algorithm for solving such continuous QCSPs. Standard
pruning operators and solution identification operators are specialized for
universally quantified inequalities. Special rules are also proposed for
handling the parameters of the constraints. First experimentation show that our
algorithm outperforms the state of the art methods.


title:
Classes on compactifications of the moduli space of curves through
  solutions to the quantum master equation

abstract:
  In this paper we describe a construction which produces classes in a
compactification of the moduli space of curves. This construction extends a
construction of Kontsevich which produces classes in the open moduli space from
the initial data of a cyclic A-infinity algebra. The initial data for our
construction is what we call a `quantum A-infinity algebra', which arises as a
type of deformation of a cyclic A-infinity algebra. The deformation theory for
these structures is described explicitly. We construct a family of examples of
quantum A-infinity algebras which extend a family of cyclic A-infinity
algebras, introduced by Kontsevich, which are known to produce all the
Miller-Morita-Mumford classes using his construction.


title:
A z = 3 Lyman Alpha Blob Associated with a Damped Lyman Alpha System
  Proximate to its Background Quasar

abstract:
  We report on the discovery of a bright Lyman alpha blob associated with the
z=3 quasar SDSSJ124020.91+145535.6 which is also coincident with strong damped
Lyman alpha absorption from a foreground galaxy (a so-called proximate damped
Lyman alpha system; PDLA). The one dimensional spectrum acquired by the Sloan
Digital Sky Survey (SDSS) shows a broad Lyman alpha emission line with a FWHM ~
500 km/s and a luminosity of L_{Lya} = 3.9e43 erg/s superposed on the trough of
the PDLA. Mechanisms for powering this large Lyman alpha luminosity are
discussed. We argue against emission from HII regions in the PDLA galaxy since
this requires an excessive star-formation rate ~ 500 Msun/yr and would
correspond to the largest Lyman alpha luminosity ever measured from a damped
Lyman alpha system or starburst galaxy. We use a Monte Carlo radiative transfer
simulation to investigate the possibility that the line emission is fluorescent
recombination radiation from the PDLA galaxy powered by the ionizing flux of
the quasar, but find that the predicted Lyman alpha flux is several orders of
magnitude lower than observed. We conclude that the Lyman alpha emission is not
associated with the PDLA galaxy at all, but instead is intrinsic to the
quasar's host and similar to the extended Lyman alpha 'fuzz' which is detected
around many AGN. PDLAs are natural coronagraphs that block their background
quasar at Lyman alpha, and we discuss how systems similar to
SDSSJ124020.91+145535.6 might be used to image the neutral hydrogen in the PDLA
galaxy in silhouette against the screen of extended Lyman alpha emission from
the background quasar.


title: Ice formation in the Arctic during summer: false-bottoms

abstract:
  The only source of ice formation in the Arctic during summer is a layer of
ice called false-bottoms between an under-ice melt pond and the underlying
ocean. Of interest is to give a mathematical model in order to determine the
simultaneous growth and ablation of false-bottoms, which is governed by both of
heat fluxes and salt fluxes. In one dimension, this problem may be considered
mathematically as a two-phase Stefan problem with two free boundaries. Our main
result is to prove the existence and uniqueness of the solution from the
initial condition.


title: Dynamical coupled-channels study of pi N --> pi pi N reactions

abstract:
  As a step toward performing a complete coupled-channels analysis of the world
data of pi N, gamma^* N --> pi N, eta N, pi pi N reactions, the pi N --> pi pi
N reactions are investigated starting with the dynamical coupled-channels model
developed in Phys. Rev. C76, 065201 (2007). The channels included are pi N, eta
N, and pi pi N which has pi Delta, rho N, and sigma N resonant components. The
non-resonant amplitudes are generated from solving a set of coupled-channels
equations with the meson-baryon potentials defined by effective Lagrangians.
The resonant amplitudes are generated from 16 bare excited nucleon (N^*) states
which are dressed by the non-resonant interactions as constrained by the
unitarity condition. The data of total cross sections and pi N and pi pi
invariant mass distributions of pi^+ p --> pi^+ pi^+ n, pi^+ pi^0p and pi^- p
--> pi^+ pi^- n, pi^- pi^0 n, pi^0 pi^0 n reactions from threshold to the
invariant mass W = 2 GeV can be described to a very large extent. We show the
importance of the coupled-channels effects and the strong interference between
the contributions from the pi Delta, sigma N, and rho N channels. The large
interference between the resonant and non-resonant amplitudes is also
demonstrated. Possible future developements are discussed.


title: LiFeAs: An Intrinsic FeAs-based Superconductor with Tc = 18K

abstract:
  The synthesis and properties of LiFeAs, a high-Tc Fe-based superconducting
stoichiometric compound, are reported. Single crystal x-ray studies reveal that
it crystallizes in the tetragonal PbFCl type (P4/nmm) with a=3.7914(7) A and
c=6.364(2) A. Unlike the known isoelectronic undoped intrinsic FeAs compounds,
LiFeAs does not show any spin-density wave behavior but exhibits
superconductivity at ambient pressures without chemical doping. It exhibits a
respectable transition temperature of Tc=18 K with electronlike carriers and a
very high critical field, Hc2(0)>80 T. LiFeAs appears to be the chemical
equivalent of the infinite layered compound of the high-Tc cuprates.


title:
Two Dimensional Density Estimation using Smooth Invertible
  Transformations

abstract:
  We investigate the problem of estimating a smooth invertible transformation f
when observing independent samples X_1, ..., X_n ~ P \circ f, where P is a
known measure. We focus on the two dimensional case where P and f are defined
on R^2. We present a flexible class of smooth invertible transformations in two
dimensions with variational equations for optimizing over the classes, then
study the problem of estimating the transformation f by penalized maximum
likelihood estimation. We apply our methodology to the case when P \circ f has
a density with respect to Lebesgue measure on R^2 and demonstrate improvements
over kernel density estimation on three examples.


title: Mode Regularization for N=1,2 SUSY Sigma Model

abstract:
  Worldline N=1 and N=2 supersymmetric sigma models in curved background are
useful to describe spin one-half and spin one particles coupled to external
gravity, respectively. It is well known that worldline path integrals in curved
space require regularization: we present here the mode-regularization for these
models, finding in particular the corresponding counterterms, both in the case
of flat and curved indices for worldline fermions. For N=1, using curved
indices we find a contribution to the counterterm from the fermions that
cancels the contribution of the bosons, leading to a vanishing total
counterterm and thus preserving the covariance and supersymmetry of the
classical action. Conversely in the case of N=2 supersymmetries we obtain a
non-covariant counterterm with both curved and flat indices. This work
completes the analysis of the known regularization schemes for N=1,2 nonlinear
sigma models in one dimension.


title: Counterexamples in Cake-Cutting

abstract:
  This article contains counterexamples to theorems and claims in Brams, Jones
and Klamler's article "Better Ways to Cut a Cake" in the December 2006 Notices
of the American Mathematical Society.


title:
Chandra Localizations and Spectra of INTEGRAL Sources in the Galactic
  Plane

abstract:
  We report on the results of observations of hard X-ray sources in the
Galactic plane with the Chandra X-ray Observatory. The hard X-ray IGR sources
were discovered by the INTEGRAL satellite, and the goals of the Chandra
observations are to provide sub-arcsecond localizations to obtain optical and
infrared counterparts and to provide constraints on their 0.3-10 keV spectra.
We obtained relatively short, ~5 ks, observations for 20 IGR sources and find a
bright Chandra source in INTEGRAL error circles in 12 cases. In 11 of these
cases, a cross-correlation with optical and/or infrared source catalogs yields
a counterpart, and the range of J-band magnitudes is 8.1-16.4. Also, in 4
cases, the Chandra X-ray spectra show evidence for absorbing material
surrounding the compact object with a column density of local material in
excess of 5x10^22 cm^-2. We confirm that IGR J00234+6141 is a Cataclysmic
Variable and IGR J14515-5542 is an Active Galactic Nucleus (AGN). We also
confirm that IGR J06074+2205, IGR J10101-5645, IGR J11305-6256, and IGR
J17200-3116 are High Mass X-ray Binaries (HMXBs). Our results (along with
follow-up optical spectroscopy reported elsewhere) indicate that IGR
J11435-6109 is an HMXB and IGR J18259-0706 is an AGN. We find that IGR
J09026-4812, IGR J18214-1318, and IGR J18325-0756 may be HMXBs. In cases where
we do not find a Chandra counterpart, the flux upper limits place interesting
constraints on the luminosities of black hole and neutron star X-ray transients
in quiescence.


title: Impurity Effects of Aerogel in Superfluid $^{3}$He

abstract:
  The discovery of superfluid $^{3}$He in high porosity silica aerogels, and
subsequent experimental and theoretical work, have led to a better general
understanding of quasiparticle scattering from impurities in unconventional
pairing systems. It is immensely helpful for understanding impurity effects in
the case of superfluid $^{3}$He that the structure of its order parameter is
well-established. An overview of impurity effects is presented with emphasis on
those experiments which have a quantitative interpretation in terms of
theoretical models for homogeneous and inhomogeneous scattering. The latter can
account successfully for most experimental results.


title:
Smoothing estimates for the Schrodinger equation with unbounded
  potentials

abstract:
  We prove a local in time smoothing estimate for a magnetic Schrodinger
equation with coefficients growing polynomially at spatial infinity. The
assumptions on the magnetic field are gauge invariant and involve only the
first two derivatives. The proof is based on the multiplier method and no
pseudofferential techniques are required.


title:
Optical Morphologies of Millijansky Radio Galaxies Observed by HST and
  in the VLA FIRST Survey

abstract:
  We report on a statistical study of the 51 radio galaxies at the millijansky
flux level from the Faint Images of the Radio Sky at Twenty centimeters,
including their optical morphologies and structure obtained with the Hubble
Space Telescope. Our optical imaging is significantly deeper (~2 mag) than
previous studies with the superior angular resolution of space-based imaging.
We that find 8/51 (16%) of the radio sources have no optically identifiable
counterpart to AB~24 mag. For the remaining 43 sources, only 25 are
sufficiently resolved in the HST images to reliably assign a visual
classification: 15 (60%) are elliptical galaxies, 2 (8%) are late-type spiral
galaxies, 1 (4%) is an S0, 3 (12%) are point-like objects (quasars), and 4
(16%) are merger systems. We find a similar distribution of optical types with
measurements of the Sersic index. The optical magnitude distribution of these
galaxies peaks at I~20.7+-0.5 AB mag, which is ~3 mag brighter than the depth
of our typical HST field and is thus not due to the WFPC2 detection limit. This
supports the luminosity-dependent density evolutionary model, where the
majority of faint radio galaxies typically have L*-optical luminosities and a
median redshift of z~0.8 with a relatively abrupt redshift cut-off at z>~2. We
discuss our results in the context of the evolution of elliptical galaxies and
active galactic nuclei.


title: Hardware/Software Co-Design for Spike Based Recognition

abstract:
  The practical applications based on recurrent spiking neurons are limited due
to their non-trivial learning algorithms. The temporal nature of spiking
neurons is more favorable for hardware implementation where signals can be
represented in binary form and communication can be done through the use of
spikes. This work investigates the potential of recurrent spiking neurons
implementations on reconfigurable platforms and their applicability in temporal
based applications. A theoretical framework of reservoir computing is
investigated for hardware/software implementation. In this framework, only
readout neurons are trained which overcomes the burden of training at the
network level. These recurrent neural networks are termed as microcircuits
which are viewed as basic computational units in cortical computation. This
paper investigates the potential of recurrent neural reservoirs and presents a
novel hardware/software strategy for their implementation on FPGAs. The design
is implemented and the functionality is tested in the context of speech
recognition application.


title: The Effect of the Sparticle Mass Spectrum on the Conversion of B-L to B

abstract:
  In the context of many leptogenesis and baryogenesis scenarios, B-L (baryon
minus the lepton number) is converted into B (baryon number) by
non-perturbative B+L violating operators in the SU(2)_L sector. We correct a
common misconversion of B-L to B in the literature in the context of
supersymmetry. More specifically, kinematic effects associated with the
sparticle masses can be generically important (typically a factor of 2/3
correction in mSUGRA scenarios), and in some cases, it may even flip the sign
between B-L and B. We give explicit formulae for converting B-L to B for
temperatures approaching the electroweak phase transition temperature from
above. Enhancements of B are also possible, leading to a mild relaxation of the
reheating temperature bounds coming from gravitino constraints.


title: Raman scattering study of (K$_x$Sr$_{1-x}$)Fe$_2$As$_2$ ($x$ = 0.0, 0.4)

abstract:
  Polarized Raman spectra of non-superconducting SrFe$_2$As$_2$ and
superconducting K$_{0.4}$Sr$_{0.6}$Fe$_2$As$_2$ ($T_c = 37$ K) are reported.
All four phonon modes (A$_{1g}$ + B$_{1g}$ + 2E$_g$) allowed by symmetry, are
found and identified. Shell model gives reasonable description of the spectra.
No detectable anomalies are observed near the tetragonal-to-orthorhombic
transition in SrFe$_2$As$_2$ or the superconducting transition in
K$_{0.4}$Sr$_{0.6}$Fe$_2$As$_2$.


title: Gluino zero-modes for calorons at finite temperature

abstract:
  We study the solutions of the Dirac equation in the adjoint
representation(gluinos) in the background field of SU(2) unit charge calorons.
Our solutions are forced to be antiperiodic in thermal time and would occur
naturally in a semiclassical approach to N=1 Super-symmetric Yang-Mills theory
at finite temperature.


title:
Comparison between the fundamental group scheme of a relative scheme and
  that of its generic fiber

abstract:
  We show that the natural morphism $\phi:\pi_1(X_{\eta},x_{\eta})\to
\pi_1(X,x)_{\eta}$ between the fundamental group scheme of the generic fiber
$X_{\eta}$ of a scheme $X$ over a connected Dedekind scheme and the generic
fiber of the fundamental group scheme of $X$ is always faithfully flat. As an
application we give a necessary and sufficient condition for a finite,
dominated pointed $G$-torsor over $X_{\eta}$ to be extended over $X$. We
finally provide examples where $\phi:\pi_1(X_{\eta},x_{\eta})\to
\pi_1(X,x)_{\eta}$ is an isomorphism..


title: Adapted coordinates in two dimensions and a proof of Puiseux's theorem

abstract:
  A method for finding Puiseux series goes back to Isaac Newton, which gives
the terms of Puiseux series through an infinite recursive process; an
additional argument is then used to show that the resulting Puiseux series are
convergent. This paper provides an argument based on Newton's method and some
ideas from resolution of singularities that gives a quick proof of both the
existence and convergence of Puiseux series. It is then shown that similar
ideas can be used to give a short proof of the existence of smooth adapted
coordinates for oscillatory integrals in two dimensions, a result first proved
in the real-analytic case by Varchenko [V] and then recently for the general
smooth case by Ikromov-Muller [IM]. The arguments of this paper are entirely
elementary.


title:
Jet power extracted from ADAF and the applications to X-ray binaries and
  radio galaxy FR dichotomy

abstract:
  We calculate the jet power of the classical Blandford-Znajek(BZ) model and
hybrid model developed by Meier based on the global solutions of advection
dominated accretion flows (ADAFs) surrounding Kerr black holes. We find that
the jet power of the hybrid model is larger than that of the pure BZ model. The
jet power will dominate over the accretion power, and the objects will enter
into "jet-power-dominated advective systems", when the accretion rate is less
than a critical value mdot_c=Mdot_c/Mdot_Edd, where 3*10^-4 < mdot_c < 5*10^-3
is a function of black hole spin parameter. The accretion power will be
dominant when mdot<mdot_c and the objects will enter into
"accretion-power-dominated advective systems." This is roughly consistent with
that constrained from the low/hard-state black hole X-ray binaries (e.g.,
Fender et al.). We calculate the maximal jet power as a function of black hole
mass with the hybrid jet formation model, and find it can roughly reproduce the
dividing line of the Ledlow-Owen relation for FR I/FR II dichotomy in the jet
power-black hole(BH) mass plane (Q_jet-M_BH) if the dimensionless accretion
rate mdot~0.01 and BH spin parameter j~0.9-0.99 are adopted. This accretion
rate mdot~0.01 is consistent with that of the critical accretion rate for the
accretion mode transition of a standard disk to an ADAF constrained from the
state transition of X-ray binaries. Our results imply that most FR I galaxies
may be in the ADAF accretion mode similar to the low/hard-state XRBs.


title: Entangled Quantum Key Distribution Over Two Free-Space Optical Links

abstract:
  We report on the first real-time implementation of a quantum key distribution
(QKD) system using entangled photon pairs that are sent over two free-space
optical telescope links. The entangled photon pairs are produced with a type-II
spontaneous parametric down-conversion source placed in a central, potentially
untrusted, location. The two free-space links cover a distance of 435 m and
1,325 m respectively, producing a total separation of 1,575 m. The system
relies on passive polarization analysis units, GPS timing receivers for
synchronization, and custom written software to perform the complete QKD
protocol including error correction and privacy amplification. Over 6.5 hours
during the night, we observed an average raw key generation rate of 565 bits/s,
an average quantum bit error rate (QBER) of 4.92%, and an average secure key
generation rate of 85 bits/s.


title:
Optical spectroscopic investigation on the coupling of electronic and
  magnetic structure in multiferroic hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho)
  thin films

abstract:
  We investigated the effects of temperature and magnetic field on the
electronic structure of hexagonal RMnO3 (R = Gd, Tb, Dy, and Ho) thin films
using optical spectroscopy. As the magnetic ordering of the system was
disturbed, a systematic change in the electronic structure was commonly
identified in this series. The optical absorption peak near 1.7 eV showed an
unexpectedly large shift of more than 150 meV from 300 K to 15 K, accompanied
by an anomaly of the shift at the Neel temperature. The magnetic field
dependent measurement clearly revealed a sizable shift of the corresponding
peak when a high magnetic field was applied. Our findings indicated strong
coupling between the magnetic ordering and the electronic structure in the
multiferroic hexagonal RMnO3 compounds.


title: Confirmation of a gapped primordial disk around LkCa 15

abstract:
  Recently, analysis of near-infrared broad-band photometry and Spitzer IRS
spectra has led to the identification of a new "pre-transitional disk" class
whose members have an inner optically thick disk separated from an outer
optically thick disk by an optically thin gap. This is in contrast to the
"transitional disks" which have inner disk holes (i.e. large reductions of
small dust from the star out to an outer optically thick wall). In LkCa 15, one
of these proposed pre-transitional disks, detailed modeling showed that
although the near-infrared fluxes could be understood in terms of optically
thick material at the dust sublimation radius, an alternative model of emission
from optically thin dust over a wide range of radii could explain the
observations as well. To unveil the true nature of LkCa 15's inner disk we
obtained a medium-resolution near-infrared spectrum spanning the wavelength
range 2-5 microns using SpeX at the NASA Infrared Telescope Facility. We report
that the excess near-infrared emission above the photosphere of LkCa 15 is a
black-body continuum which can only be due to optically thick material in an
inner disk around the star. When this confirmation of a primordial inner disk
is combined with earlier observations of an inner edge to LkCa 15's outer disk
it reveals a gapped structure. Forming planets emerge as the most likely
mechanism for clearing the gap we detect in this evolving disk.


title:
Rate and power allocation under the pairwise distributed source coding
  constraint

abstract:
  We consider the problem of rate and power allocation for a sensor network
under the pairwise distributed source coding constraint. For noiseless
source-terminal channels, we show that the minimum sum rate assignment can be
found by finding a minimum weight arborescence in an appropriately defined
directed graph. For orthogonal noisy source-terminal channels, the minimum sum
power allocation can be found by finding a minimum weight matching forest in a
mixed graph. Numerical results are presented for both cases showing that our
solutions always outperform previously proposed solutions. The gains are
considerable when source correlations are high.


title: In-beam gamma-ray spectroscopy at the proton dripline: 23Al

abstract:
  We report on the first in-beam $\gamma$-ray spectroscopy of \nuc{23}{Al}
using two different reactions at intermediate beam energies: inelastic
scattering off \nuc{9}{Be} and heavy-ion induced one-proton pickup,
\nuc{9}{Be}(\nuc{22}{Mg},\nuc{23}{Al}$+\gamma$)X, at 75.1 MeV/nucleon. A
$\gamma$-ray transition at 1616(8) keV -- exceeding the proton separation
energy by 1494 keV -- was observed in both reactions. From shell model and
proton decay calculations we argue that this $\gamma$-ray decay proceeds from
the core-excited $7/2^+$ state to the $5/2^+$ ground state of \nuc{23}{Al}. The
proposed nature of this state, $[\nuc{22}{Mg}(2^+_1) \otimes \pi
d_{5/2}]_{7/2+}$, is consistent with the presence of a gamma-branch and with
the population of this state in the two reactions.


title: A cone theorem for nef curves

abstract:
  Following ideas of V. Batyrev, we prove an analogue of the Cone Theorem for
the closed cone of nef curves: an enlargement of the cone of nef curves is the
closure of the sum of a K_X-non-negative portion and countably many
K_X-negative coextremal rays. An example shows that this enlargement is
necessary. We also describe the relationship between K_X-negative faces of this
cone and the possible outcomes of the minimal model program.


title: Project Lyman

abstract:
  We explore the design of a space mission, Project Lyman, which has the goal
of quantifying the ionization history of the universe from the present epoch to
a redshift of z ~ 3. Observations from WMAP and SDSS show that before a
redshift of z >~ 6 the first collapsed objects, possibly dwarf galaxies,
emitted Lyman continuum (LyC) radiation shortward of 912 A, reionizing most of
the universe. How LyC escapes from galactic environments, whether it induces
positive or negative feedback on the local and global collapse of structures,
and the role played by clumping, molecules, metallicity and dust are major
unanswered theoretical questions, requiring observational constraint. Numerous
intervening Lyman limit systems, which frustrate the detection of LyC from high
z objects, thin below z ~ 3 where there are a few objects with apparently very
high fesc. At low z there are only controversial detections and a handful of
upper limits. A wide-field multi-object spectroscopic survey with moderate
spectral and spatial resolution can quantify fesc within diverse spatially
resolved galactic environments over redshifts with significant evolution in
galaxy assemblage and quasar activity. It can also calibrate LyC escape against
Ly-alpha escape, providing an essential tool to JWST for probing the beginnings
of reionization. We present calculations showing the evolution of the
characteristic apparent magnitude of star-forming galaxy luminosity functions
at 900 A, as a function of redshift and assumed escape fraction to determine
the required aperture for detecting LyC. We review our efforts to build a
pathfinding dual order multi-object spectro/telescope with a (0.5deg)^2
field-of-view, using a GSFC microshutter array, and crossed delay-line
micro-channel plate detector.


title:
Local structural changes in paramagnetic and charge ordered phases of
  Sm0.2Pr0.3Sr0.5MnO3: An EXAFS Study

abstract:
  Sm{0.5-x}Pr{x}Sr{0.5}MnO{3} exhibits variety of ground states as x is varied
from 0 to 0.5. At an intermediate doping of x = 0.3 a charge-ordered CE type
antiferromagnetic insulating (AFI) ground state is seen. The transition to this
ground state is from a paramagnetic insulating (PMI) phase through a
ferromagnetic metallic phase (FMM). Local structures in PMI and AFI phases of x
= 0.3 sample have been investigated using Pr K-edge and Sm K-edge Extended
X-ray Absorption Fine Structure (EXAFS). It can be seen that the tilting and
rotation of the MnO6 octahedra about the b-axis are responsible for the charge
ordered CE-type antiferromagnetic ground state at low temperatures. In addition
a shift in the position of the rare earth ion along the c-axis has to be
considered to account for observed distribution of bond distances around the
rare earth ion.


title: Multifractality in Rotational Percolation Models

abstract:
  In rotationally constrained percolation models, a site of a percolation
cluster could be occupied more than once from different directions due to the
nature of the rotational constraint. A state variable $s_i$ is assigned to each
lattice site whose value corresponds to the number times it has been visited
during the growth of a cluster. It is proposed here that the percolation
transition and the multifractal aspects of infinite percolation clusters under
rotational constraint can be studied defining suitable measures in terms of the
state variable $s_i$. This method does not require to introduce any external
agency like an electric current or a random walker in order to explore
multifractality as in the case of ordinary percolation. The state variable
representation also describes the universality class of the percolation models
appropriately.


title:
Does the three site Higgsless model survive the electroweak precision
  tests at loop?

abstract:
  We complete the list of one loop renormalization group equations and matching
conditions relevant for the computation of the electroweak precision parameters
$S$ and $T$ in the three site Higgsless model. We obtain one-loop formulas for
$S$ and $T$ expressed in terms of physical observables such as the KK gauge
boson mass $M_{W'}$, the KK fermion mass $M$, and the KK gauge boson ($W'$)
couplings with light quarks and leptons $g_{W'ff}$. It is shown that these
physical observables, $M_{W'}$, $M$ and $g_{W'ff}$ are severely constrained by
the electroweak precision data. Unlike the tree level analysis on the ideally
delocalized fermion, we find that perfect fermiophobity of $W'$ is ruled out by
the precision data. We also study the cutoff dependence of our analysis.
Although the model is non-renormalizable, the dependence on the cutoff
parameter $\Lambda$ is shown to be non-significant.


title:
Characteristics of Deterministic and Stochastic Sandpile Models in a
  Rotational Sandpile Model

abstract:
  Rotational constraint representing a local external bias generally has
non-trivial effect on the critical behavior of lattice statistical models in
equilibrium critical phenomena. In order to study the effect of rotational bias
in a out of equilibrium situation like self-organized criticality, a new two
state ``quasi-deterministic'' rotational sandpile model is developed here
imposing rotational constraint on the flow of sand grains. An extended set of
new critical exponents are found to characterize the avalanche properties at
the non-equilibrium steady state of the model. The probability distribution
functions are found to obey usual finite size scaling supported by negative
time autocorrelation between the toppling waves. The model exhibits
characteristics of both deterministic and stochastic sandpile models.


title: Finite-Size Scaling for Directed Percolation Models

abstract:
  A simple finite-size scaling theory is proposed here for anisotropic
percolation models considering the cluster size distribution function as
generalized homogeneous function of the system size and two connectivity
lengths. The proposed scaling theory has been verified numerically on two
different anisotropic percolation models.


title: Exclusive Pion-production and the Relation to Transversity

abstract:
  Exclusive $\pi^0$ electroproduction from nucleons is suggested for extracting
the tensor charge and other quantities related to transversity from
experimental data. This process isolates C-parity odd and chiral odd
combinations of t-channel exchange quantum numbers. In a hadronic picture it
connects the meson production amplitudes to C-odd Regge exchanges with final
state interactions. In a description based on partonic degrees of freedom, the
helicity structure for this C-odd process relates to the quark helicity flip,
or chiral odd generalized parton distributions.


title: An efficient way to reduce losses of left-handed metamaterials

abstract:
  We propose a simple and effective way to reduce the losses in left-handed
metamaterials by manipulating the values of the effective parameters R, L, and
C. We investigate the role of losses of the short-wire pairs and the fishnet
structures. Increasing the effective inductance to capacitance ratio, L/C,
reduces the losses and the figure of merit can increase substantially,
especially at THz frequencies and in the optical regime.


title: A new characteristic property of rich words

abstract:
  Originally introduced and studied by the third and fourth authors together
with J. Justin and S. Widmer in arXiv:0801.1656, rich words constitute a new
class of finite and infinite words characterized by containing the maximal
number of distinct palindromes. Several characterizations of rich words have
already been established. A particularly nice characteristic property is that
all 'complete returns' to palindromes are palindromes. In this note, we prove
that rich words are also characterized by the property that each factor is
uniquely determined by its longest palindromic prefix and its longest
palindromic suffix.


title: A General Approach for the Exact Solution of the Schrodinger Equation

abstract:
  The Schr\"{o}dinger equation is solved exactly for some well known
potentials. Solutions are obtained reducing the Schr\"{o}dinger equation into a
second order differential equation by using an appropriate coordinate
transformation. The Nikiforov-Uvarov method is used in the calculations to get
energy eigenvalues and the corresponding wave functions.


title:
Recursion Relation for the Feynman Diagrams of the Effective Action for
  the Third Legendre Transformation

abstract:
  We derive a recursion relation of the Feynman diagrams of the effective
action for the third Legendre transformation in case of the bosonic field
theory with cubic interaction. We apply the recursion relation to obtain the
Feynman diagrams of the effective action for the third Legendre transformation
up to the five-loop order. The three-particle irreducibility of the Feynman
diagrams of the effective action for the third Legendre transformation is shown
by induction.


title: A field-theoretic model for Hodge theory

abstract:
  We demonstrate that the four (3 + 1)-dimensional free Abelian 2-form gauge
theory presents a tractable field theoretical model for the Hodge theory where
the well-defined symmetry transformations correspond to the de Rham
cohomological operators of differential geometry. The conserved charges,
corresponding to the above continuous symmetry transformations, obey an algebra
that is reminiscent of the algebra obeyed by the cohomological operators. The
discrete symmetry transformation of the theory represents the realization of
the Hodge duality operation that exists in the relationship between the
exterior and co-exterior derivatives of differential geometry. Thus, we provide
the realizations of all the mathematical quantities, associated with the de
Rham cohomological operators, in the language of the symmetries of the present
4D free Abelian 2-form gauge theory.


title:
Multifractal analysis of the fracture surfaces of foamed
  polypropylene/polyethylene blends

abstract:
  The two-dimensional multifractal detrended fluctuation analysis is applied to
reveal the multifractal properties of the fracture surfaces of foamed
polypropylene/polyethylene blends at different temperatures. Nice power-law
scaling relationship between the detrended fluctuation function $F_{q}$ and the
scale $s$ is observed for different orders $q$ and the scaling exponent $h(q)$
is found to be a nonlinear function of $q$, confirming the presence of
multifractality in the fracture surfaces. The multifractal spectra $f(\alpha)$
are obtained numerically through Legendre transform. The shape of the
multifractal spectrum of singularities can be well captured by the width of
spectrum $\Delta\alpha$ and the difference of dimension $\Delta f$. With the
increase of the PE content, the fracture surface becomes more irregular and
complex, as is manifested by the facts that $\Delta\alpha$ increases and
$\Delta f$ decreases from positive to negative. A qualitative interpretation is
provided based on the foaming process.


title:
Comment on the paper "Search for oscillation of the electron-capture
  decay probability of $^{142}$Pm" at arXiv:0807.0649v1

abstract:
  It is argued that orbital electron-capture decays of neutral $^{142}$Pm atoms
implanted into the lattice of a solid (LBNL experiment) do not fulfil the
constraints of true two-body beta decays, since momentum as well as energy of
the final state are distributed among three objects, namely the electron
neutrino, the recoiling daughter atom and the lattice phonons. To our
understanding, this could be a reason for the non-observation of a periodic
time modulation in the number of electron-capture decays of implanted neutral
$^{142}$Pm atoms.


title: Maximal analytic extensions of the Emparan-Reall black ring

abstract:
  We construct a Kruskal-Szekeres-type analytic extension of the Emparan-Reall
black ring, and investigate its geometry. We prove that the extension is
maximal, globally hyperbolic, and unique within a natural class of extensions.
The key to those results is the proof that causal geodesics are either
complete, or approach a singular boundary in finite affine time. Alternative
maximal analytic extensions are also constructed.


title:
A note on K$\ddot{a}$hler manifolds with almost nonnegative bisectional
  curvature

abstract:
  In this note we prove the following result: There is a positive constant
$\epsilon(n,\Lambda)$ such that if $M^n$ is a simply connected compact
K$\ddot{a}$hler manifold with sectional curvature bounded from above by
$\Lambda$, diameter bounded from above by 1, and with holomorphic bisectional
curvature $H \geq -\epsilon(n,\Lambda)$, then $M^n$ is diffeomorphic to the
product $M_1\times ... \times M_k$, where each $M_i$ is either a complex
projective space or an irreducible K$\ddot{a}$hler-Hermitian symmetric space of
rank $\geq 2$. This resolves a conjecture of F. Fang under the additional upper
bound restrictions on sectional curvature and diameter.


title: The energy space for the Gross-Pitaevskii equation with magnetic field

abstract:
  We study the energy space for the Gross-Pitaevskii equation with magnetic
field and non-vanishing conditions at infinity. We provide necessary and
sufficient conditions on the magnetic field for which the energy space is
non-empty.


title:
Magnetic properties of the insulating ferromagnetic phase in strained
  Pr_0.6Ca_0.4MnO_3 thin films

abstract:
  Bulk magnetization in Pr_{0.6}Ca_{0.4}MnO_3 thin films with tensile (SrTiO_3)
and compressive (LaAlO_3) substrate-induced strain is compared to the
magnetooptical Kerr effect (MOKE) measurements. In the absence of an external
magnetic field, in both films, a stable ferromagnetic insulating majority phase
coexists with an antiferromagnetic insulating phase below ~120K. MOKE
measurements indicate that at 5K a metastable ferromagnetic metallic (FM) phase
is formed at the surface of the stretched film in a magnetic field below 1.1T
already, while in the bulk the FM phase starts to form in the field above ~4T
in both films.


title:
Open clusters as key tracers of Galactic chemical evolution. III.
  Element abundances in Berkeley 20, Berkeley 29, Collinder 261, and Melotte 66

abstract:
  Galactic open clusters are since long recognized as one of the best tools for
investigating the radial distribution of iron and other metals. We employed
FLAMES at VLT to collect UVES spectra of bright giant stars in a large sample
of open clusters, spanning a wide range of Galactocentric distances, ages, and
metallicities. We present here the results for four clusters: Berkeley 20 and
Berkeley 29, the two most distant clusters in the sample; Collinder 261, the
oldest and the one with the minimum Galactocentric distance; Melotte 66.
Equivalent width analysis was carried out using the spectral code MOOG and
Kurucz model atmospheres to derive abundances of Fe, Al, Mg, Si, Ca, Ti, Cr,
Ni, Ba; non-LTE Na abundances were derived by direct line-profile fitting. We
obtain subsolar metallicities for the two anticenter clusters Be 20
([Fe/H]=-0.30, rms=0.02) and Be 29 ([Fe/H]=-0.31, rms=0.03), and for Mel 66
([Fe/H]=-0.33, rms=0.03), located in the third Galactic quadrant, while Cr 261,
located toward the Galactic center, has higher metallicity ([Fe/H]=+0.13,
rms=0.05 dex). The alpha-elements Si, Ca and Ti, and the Fe-peak elements Cr
and Ni are in general close to solar; the s-process element Ba is enhanced.
Non-LTE computations of Na abundances indicate solar scaled values, suggesting
that the enhancement in Na previously determined in giants in open clusters
could be due to neglected non-LTE effects. Our results support the presence of
a steep negative slope of the Fe radial gradient up to about 10-11 kpc from the
Galactic center, while in the outer disk the [Fe/H] distribution seems flat.
All the elemental ratios measured are in very good agreement with those found
for disk stars of similar metallicity and no trend with Galactocentric distance
seems to be present.


title: Negative radiation pressure in case of two interacting fields

abstract:
  We study a simple toy model, which although probably does not have any direct
physical applications, can serve as a nice pedagogical example for explanation
strange phenomenon of negative radiation pressure and can also give some
insight for understanding the interaction between radiation and a vortex. The
model discussed is a classical field theory of two interacting scalar fields in
1+1 d. Without coupling one of the fields is governed by the ordinary $\phi^4$
equation and the second one obeys the Klein-Gordon equation. The possibility of
existence of the {\it negative radiation pressure} with a respect to the mass
ratio of those two fields is discussed.


title: Deformed quantum statistics in two-dimensions

abstract:
  It is known from the early work of May in 1964 that ideal Bose gas do not
exhibit condensation phenomenon in two dimensions. On the other hand, it is
also known that the thermostatistics arising from q-deformed oscillator algebra
has no connection with the spatial dimensions of the system. Our recent work
concerns the study of important thermodynamic functions such as the entropy,
occupation number, internal energy and specific heat in ordinary three spatial
dimensions, where we established that such thermostatistics is developed by
consistently replacing the ordinary thermodynamic derivatives by the Jackson
derivatives. The thermostatistics of q-deformed bosons and fermions in two
spatial dimensions is an unresolved question and that is the subject of this
investigation. We study the principal thermodynamic functions of both bosons
and fermions in the two dimensional q-deformed formalism and we find that,
different from the standard case, the specific heat of q-boson and q-fermion
ideal gas, at fixed temperature and number of particle, are no longer
identical.


title:
Evidence for a narrow N(1685) resonance in eta photoproduction off the
  nucleon

abstract:
  Revised analysis of Sigma beam asymmetry for eta photoproduction off the free
proton from GRAAL is presented. New analysis reveals a narrow structure near W
~1.685 GeV. We describe this structure by the contribution of a narrow
resonance with quantum numbers P_{11}, or P_{13}, or D_{13}. Being considered
together with the recent observations of a bump-like structure at W~1.68 GeV in
the quasi-free eta photoproduction off the neutron, this result provides an
evidence for a narrow (Gamma < 25 MeV) N*(1685) resonance. Properties of this
possible new nucleon state, namely the mass, the narrow width, and the much
stronger photocoupling to the neutron, are similar to those predicted for the
non-strange member of anti-decouplet of exotic baryons.


title: A note on dark energy induced by D-brane motion

abstract:
  In this note we study the possibility of obtaining dark energy solution in a
D-brane scenario in a warped background that includes brane-position dependent
corrections for the non-perturbative superpotential. The volume modulus is
stabilized at instantaneous minima of the potential. Though the model can
account for the existence of dark energy within present observational bound -
fine-tuning of the model parameters becomes unavoidable. Moreover, the model
does not posses a tracker solution.


title:
An output-sensitive algorithm for multi-parametric LCPs with sufficient
  matrices

abstract:
  This paper considers the multi-parametric linear complementarity problem
(pLCP) with sufficient matrices. The main result is an algorithm to find a
polyhedral decomposition of the set of feasible parameters and to construct a
piecewise affine function that maps each feasible parameter to a solution of
the associated LCP in such a way that the function is affine over each cell of
the decomposition. The algorithm is output-sensive in the sense that its time
complexity is polynomial in the size of the input and linear in the size of the
output, when the problem is non-degenerate. We give a lexicographic
perturbation technique to resolve degeneracy as well. Unlike for the
non-parametric case, the resolution turns out to be nontrivial, and in
particular, it involves linear programming (LP) duality and multi-objective LP.


title: Direct Observation of Local Magnetic Field Generated by Micromagnet

abstract:
  Using standard nuclear magnetic resonance (NMR) technique and a
well-fabricated sample, we have succeeded in directly observing local magnetic
field generated by a micro-magnet Ni45Fe55 (the thickness of 400-nm) which was
sputtered on an Al layer of 20-nm thickness. Improved sensitivity of our NMR
technique enabled us to clearly observe Al-NMR signals, which are confirmed to
come from Al nuclei in the 20-nm layers. From the analysis of the Al-NMR
spectra, the local magnetic field was found to be +0.17+-0.02 (-0.20+-0.01)
Tesla, the sign of which is consistent with the geometry that the external
magnetic field was applied perpendicular (parallel) to the Al layer. The
present study gives a potential key element toward realizing higher resolution
in magnetic resonance imaging (MRI).


title: Approaches to Single Photon Detection

abstract:
  We present recent results on our development of single photon detectors,
including: gated and free-running InGaAs/InP avalanche photodiodes; hybrid
detection systems based on sum-frequency generation and Si APDs; and SSPDs
(superconducting single photon detectors), for telecom wavelengths; as well as
SiPM (Silicon photomultiplier) detectors operating in the visible regime.