title:
Energy Dissipation and Fluctuation-Response in Driven Quantum Langevin
  Dynamics

abstract:
  Energy dissipation in a nonequilibrium steady state is studied in driven
quantum Langevin systems. We study energy dissipation flow to thermal
environment, and obtain a general formula for the average rate of energy
dissipation using an autocorrelation function for the system variable. This
leads to a general expression of the equality that connects the violation of
the fluctuation-response relation to the rate of energy dissipation, the
classical version of which was first studied by Harada and Sasa. We also point
out that the expression depends on coupling form between system and reservoir.


title: CaCrO3: an anomalous antiferromagnetic metallic oxide

abstract:
  Combining infrared reflectivity, transport, susceptibility and several
diffraction techniques, we find compelling evidence that CaCrO3 is a rare case
of a metallic and antiferromagnetic transition-metal oxide with a
three-dimensional electronic structure. LSDA calculations correctly describe
the metallic behavior as well as the anisotropic magnetic ordering pattern of C
type: The high Cr valence state induces via sizeable pd hybridization
remarkably strong next-nearest neighbor interactions stabilizing this ordering.
The subtle balance of magnetic interactions gives rise to magneto-elastic
coupling, explaining pronounced structural anomalies observed at the magnetic
ordering transition.


title: Construction of a Wilson action for the Wess-Zumino model

abstract:
  We construct a Wilson action for the Wess-Zumino model by applying the exact
renormalization group perturbatively. Using neither superfields nor auxiliary
fields, we construct a supersymmetric action only with complex scalar and
Majorana spinor fields. We adopt the BRST (antifield) formalism to show the
consistency of the construction to all orders in loop expansions. The resulting
action has a quadratically divergent scalar mass term which is absent in the
superfield formalism.


title: de Sitter vacua in no-scale supergravities and Calabi-Yau string models

abstract:
  We perform a general analysis on the possibility of obtaining metastable
vacua with spontaneously broken N=1 supersymmetry and non-negative cosmological
constant in the moduli sector of string models. More specifically, we study the
condition under which the scalar partners of the Goldstino are non-tachyonic,
which depends only on the Kahler potential. This condition is not only
necessary but also sufficient, in the sense that all of the other scalar fields
can be given arbitrarily large positive square masses if the superpotential is
suitably tuned. We consider both heterotic and orientifold string
compactifications in the large-volume limit and show that the no-scale property
shared by these models severely restricts the allowed values for the
`sGoldstino' masses in the superpotential parameter space. We find that a
positive mass term may be achieved only for certain types of compactifications
and specific Goldstino directions. Additionally, we show how subleading
corrections to the Kahler potential which break the no-scale property may allow
to lift these masses.


title:
Addendum to "Ricci-flat holonomy: a Classification": the case of
  Spin(10)

abstract:
  This note fills a hole in the author's previous paper ``Ricci-Flat Holonomy:
a Classification'', by dealing with irreducible holonomy algebras that are
subalgebras or real forms of $\mbb{C} \oplus \mf{spin}(10,\mbb{C})$. These all
turn out to be of Ricci-type.


title:
Computational Efficiency of Frequency-- and Time--Domain Calculations of
  Extreme Mass--Ratio Binaries: Equatorial Orbits

abstract:
  Gravitational waveforms and fluxes from extreme mass--ratio inspirals can be
computed using time--domain methods with accuracy that is fast approaching that
of frequency--domain methods. We study in detail the computational efficiency
of these methods for equatorial orbits of fast spinning Kerr black holes, and
find the number of modes needed in either method --as functions of the orbital
parameters-- in order to achieve a desired accuracy level. We then estimate the
total computation time and argue that for high eccentricity orbits the
time--domain approach is more efficient computationally. We suggest that in
practice low--$m$ modes are computed using the frequency--domain approach, and
high--$m$ modes are computed using the time--domain approach, where $m$ is the
azimuthal mode number.


title: Eigenvalue bracketing for discrete and metric graphs

abstract:
  We develop eigenvalue estimates for the Laplacians on discrete and metric
graphs using different types of boundary conditions at the vertices of the
metric graph. Via an explicit correspondence of the equilateral metric and
discrete graph spectrum (also in the ``exceptional'' values of the metric graph
corresponding to the Dirichlet spectrum) we carry over these estimates from the
metric graph Laplacian to the discrete case. We apply the results to covering
graphs and present examples where the covering graph Laplacians have spectral
gaps.


title:
Quantum enveloping algebras with von Neumann regular Cartan-like
  generators and the Pierce decomposition

abstract:
  Quantum bialgebras derivable from Uq(sl2) which contain idempotents and von
Neumann regular Cartan-like generators are introduced and investigated. Various
types of antipodes (invertible and von Neumann regular) on these bialgebras are
constructed, which leads to a Hopf algebra structure and a von Neumann-Hopf
algebra structure, respectively. For them, explicit forms of some particular
R-matrices (also, invertible and von Neumann regular) are presented, and the
latter respects the Pierce decomposition.

categories: math.QA hep-th math-ph math.MP math.RA quant-ph


title:
Desingularized fiber products of semi-stable elliptic surfaces with
  vanishing third Betti number

abstract:
  Desingularized fiber products of semi-stable, non-isotrivial jacobian
elliptic surfaces with vanishing third Betti number are classified. Such
varieties may play a role in the study of supersingular threefolds, of the
deformation theory of varieties with trivial canonical bundle, and of the
arithmetic degenerations of rigid Calabi-Yau threefolds.


title: P is a proper subset of NP

abstract:
  The purpose of this article is to examine and limit the conditions in which
the P complexity class could be equivalent to the NP complexity class. Proof is
provided by demonstrating that as the number of clauses in a NP-complete
problem approaches infinity, the number of input sets processed per computation
performed also approaches infinity when solved by a polynomial time solution.
It is then possible to determine that the only deterministic optimization of a
NP-complete problem that could prove P = NP would be one that examines no more
than a polynomial number of input sets for a given problem.
  It is then shown that subdividing the set of all possible input sets into a
representative polynomial search partition is a problem in the FEXP complexity
class. The findings of this article are combined with the findings of other
articles in this series of 4 articles. The final conclusion will be
demonstrated that P =/= NP.


title:
Flux distribution in metabolic networks close to optimal biomass
  production

abstract:
  We study a statistical model describing the steady state distribution of the
fluxes in a metabolic network. The resulting model on continuous variables can
be solved by the cavity method. In particular analytical tractability is
possible solving the cavity equation over an ensemble of networks with the same
degree distribution of the real metabolic network. The flux distribution that
optimizes production of biomass has a fat tail with a power-law exponent
independent on the structural properties of the underling network. These
results are in complete agreement with the Flux-Balance-Analysis outcome of the
same system and in qualitative agreement with the experimental results.


title: Construction of the Digamma Function by Derivative Definition

abstract:
  The Digamma and Polygamma functions are important tools in mathematical
physics, not only for its many properties but also for the applications in
statistical mechanics and stellar evolution. In many textbooks is found its
develop almost by the same procedure. In this paper expressions for the Digamma
and Polygamma functions, in terms of hypergeometric functions, are found
through the derivative definition.


title: The functors Wbar and Diag o Nerve are simplicially homotopy equivalent

abstract:
  Given a simplicial group G, there are two known classifying simplicial set
constructions, the Kan classifying simplicial set Wbar G and Diag N G, where N
denotes the dimensionwise nerve. They are known to be weakly homotopy
equivalent. We will show that Wbar G is a strong simplicial deformation retract
of Diag N G. In particular, Wbar G and Diag N G are simplicially homotopy
equivalent.


title: Towards algebraic methods for maximum entropy estimation

abstract:
  We show that various formulations (e.g., dual and Kullback-Csiszar
iterations) of estimation of maximum entropy (ME) models can be transformed to
solving systems of polynomial equations in several variables for which one can
use celebrated Grobner bases methods. Posing of ME estimation as solving
polynomial equations is possible, in the cases where feature functions
(sufficient statistic) that provides the information about the underlying
random variable in the form of expectations are integer valued.


title:
Improved time-frequency analysis of extreme-mass-ratio inspiral signals
  in mock LISA data

abstract:
  The planned Laser Interferometer Space Antenna (LISA) is expected to detect
gravitational wave signals from ~100 extreme-mass-ratio inspirals (EMRIs) of
stellar-mass compact objects into massive black holes. The long duration and
large parameter space of EMRI signals makes data analysis for these signals a
challenging problem. One approach to EMRI data analysis is to use
time-frequency methods. This consists of two steps: (i) searching for tracks
from EMRI sources in a time-frequency spectrogram, and (ii) extracting
parameter estimates from the tracks. In this paper we discuss the results of
applying these techniques to the latest round of the Mock LISA Data Challenge,
Round 1B. This analysis included three new techniques not used in previous
analyses: (i) a new Chirp-based Algorithm for Track Search for track detection;
(ii) estimation of the inclination of the source to the line of sight; (iii) a
Metropolis-Hastings Monte Carlo over the parameter space in order to find the
best fit to the tracks.


title: Can hyperbolic phase of Brans-Dicke field account for Dark Matter?

abstract:
  We show that the introduction of a hyperbolic phase for Brans-Dicke (BD)
field results in a flat vacuum cosmological solution of Hubble parameter H and
fractional rate of change of BD scalar field, F which asymptotically approach
constant values. At late stages, hyperbolic phase of BD field behaves like dark
matter.


title: Visco-potential free-surface flows and long wave modelling

abstract:
  In a recent study [DutykhDias2007] we presented a novel visco-potential free
surface flows formulation. The governing equations contain local and nonlocal
dissipative terms. From physical point of view, local dissipation terms come
from molecular viscosity but in practical computations, rather eddy viscosity
should be used. On the other hand, nonlocal dissipative term represents a
correction due to the presence of a bottom boundary layer. Using the standard
procedure of Boussinesq equations derivation, we come to nonlocal long wave
equations. In this article we analyse dispersion relation properties of
proposed models. The effect of nonlocal term on solitary and linear progressive
waves attenuation is investigated. Finally, we present some computations with
viscous Boussinesq equations solved by a Fourier type spectral method.

categories: physics.flu-dyn math-ph math.AP math.MP math.NA nlin.PS nlin.SI physics.ao-ph physics.class-ph physics.comp-ph physics.geo-ph


title: Instantons and Donaldson-Thomas Invariants

abstract:
  We review some recent progress in understanding the relation between a six
dimensional topological Yang-Mills theory and the enumerative geometry of
Calabi-Yau threefolds. The gauge theory localizes on generalized instanton
solutions and is conjecturally equivalent to Donaldson-Thomas theory. We
evaluate the partition function of the U(N) theory in its Coulomb branch on
flat space by employing equivariant localization techniques on its
noncommutative deformation. Geometrically this corresponds to a higher
dimensional generalization of the ADHM formalism. This formalism can be
extended to a generic toric Calabi-Yau.


title:
On the interpretation of the cosmic-ray anisotropy at ultra-high
  energies

abstract:
  A natural interpretation of the correlation between nearby Active Galactic
Nuclei (AGN) and the highest-energy cosmic rays observed recently by the Pierre
Auger Collaboration is that the sources of the cosmic rays are either AGN or
other objects with a similar spatial distribution (the ``AGN hypothesis''). We
question this interpretation. We calculate the expected distribution of the
arrival directions of cosmic rays under the AGN hypothesis and argue that it is
not supported by the data, one of manifestations of the discrepancy being the
deficit of events from the direction of the Virgo supercluster. We briefly
discuss possible alternative explanations including the origin of a significant
part of the observed events from Cen A.


title: The sensitivity of coded mask telescopes

abstract:
  Simple formulae are often used to estimate the sensitivity of coded mask
X-ray or gamma-ray telescopes, but these are strictly only applicable if a
number of basic assumptions are met. Complications arise, for example, if a
grid structure is used to support the mask elements, if the detector spatial
resolution is not good enough to completely resolve all the detail in the
shadow of the mask or if any of a number of other simplifying conditions are
not fulfilled. We derive more general expressions for the Poisson-noise-limited
sensitivity of astronomical telescopes using the coded mask technique, noting
explicitly in what circumstances they are applicable. The emphasis is on using
nomenclature and techniques that result in simple and revealing results. Where
no convenient expression is available a procedure is given which allows the
calculation of the sensitivity. We consider certain aspects of the optimization
of the design of a coded mask telescope and show that when the detector spatial
resolution and the mask to detector separation are fixed, the best source
location accuracy is obtained when the mask elements are equal in size to the
detector pixels.


title: Phase reciprocity of spin-wave excitation by a microstrip antenna

abstract:
  Using space-, time- and phase-resolved Brillouin light scattering
spectroscopy we investigate the difference in phase of the two
counterpropagating spin waves excited by the same microwave microstrip
transducer. These studies are performed both for backward volume magnetostatic
waves and magnetostatic surface waves in an in-plane magnetized yttrium iron
garnet film. The experiments show that for the backward volume magnetostatic
spin waves (which are reciprocal and excited symmetrically in amplitude) there
is a phase difference of $\pi$ associated with the excitation process and thus
the phase symmetry is distorted. On the contrary, for the magnetostatic surface
spin waves (which are non-reciprocal and unsymmetrical in amplitude) the phase
symmetry is preserved (there is no phase difference between the two waves
associated with the excitation). Theoretical analysis confirms this effect.


title:
Extensions of the Frobenius to ring of differential operators on
  polynomial algebra in prime characteristic

abstract:
  Let $K$ be a field of characteristic $p>0$. It is proved that each
automorphism $\s \in \Aut_K(\CDPn)$ of the ring $\CDPn$ of differential
operators on a polynomial algebra $P_n= K[x_1, ..., x_n]$ is {\em uniquely}
determined by the elements $\s (x_1), ... ,\s (x_n)$, and the set $\Frob
(\CDPn)$ of all the extensions of the Frobenius from certain maximal
commutative polynomial subalgebras of $\CDPn$, like $P_n$, is equal to
$\Aut_K(\CDPn) \cdot \CF$ where $\CF$ is the set of all the extensions of the
Frobenius from $P_n$ to $\CDPn$ that leave invariant the subalgebra of scalar
differential operators. The set
  $\CF$ is found explicitly, it is large (a typical extension depends on {\em
countably} many independent parameters).


title:
The special subgroup of invertible non-commutative rational power series
  as a metric group

abstract:
  We give an easy proof of Sch\"utzenberger's Theorem stating that
non-commutative formal power series are rational if and only if they are
recognisable. A byproduct of this proof is a natural metric on a subgroup of
invertible rational non-commutative power series. We describe a few features of
this metric group.


title:
Structural relaxation due to electronic correlations in the paramagnetic
  insulator KCuF3

abstract:
  A computational scheme for the investigation of complex materials with
strongly interacting electrons is formulated which is able to treat atomic
displacements, and hence structural relaxation, caused by electronic
correlations. It combines ab initio band structure and dynamical mean-field
theory and is implemented in terms of plane-wave pseudopotentials. The
equilibrium Jahn-Teller distortion and antiferro-orbital order found for
paramagnetic KCuF3 agree well with experiment.


title: Regularity of the minimizers in the composite membrane problem in R^2

abstract:
  We study the regularity of minimizers to the composite membrane problem in
the plane (ie given a domain omega and a positive number A, smaller than the
measure of omega, minimize the first Dirichlet eigenvalue for the Schrodinger
operator with potential equal to a fixed multiple of the characteristic
function of a subset D of omega, with measure A). We show that for minimizers,
the boundary of D is analytic.


title: Graph pegging numbers

abstract:
  In graph pegging, we view each vertex of a graph as a hole into which a peg
can be placed, with checker-like ``pegging moves'' allowed. Motivated by
well-studied questions in graph pebbling, we introduce two pegging quantities.
The pegging number (respectively, the optimal pegging number) of a graph is the
minimum number of pegs such that for every (respectively, some) distribution of
that many pegs on the graph, any vertex can be reached by a sequence of pegging
moves. We prove several basic properties of pegging and analyze the pegging
number and optimal pegging number of several classes of graphs, including
paths, cycles, products with complete graphs, hypercubes, and graphs of small
diameter.


title: The chiral condensate in holographic models of QCD

abstract:
  Bottom-up holographic models of QCD, inspired by the AdS/CFT correspondence,
have shown a remarkable degree of phenomenological success. However, they rely
on a number of bold assumptions. We investigate the reliability of one of the
key assumptions, which involves matching the parameters of these models to QCD
at high 4D momentum $q^2$ and renormalization scale $\mu^2$. We show that this
leads to phenomenological and theoretical inconsistencies for scale-dependent
quantities such as $\bra \bar{q}q\ket$


title: Isocurvature, non-gaussianity and the curvaton model

abstract:
  Recent analyses of the statistical distribution of the temperature
anisotropies in the CMB do not rule out the possibility that there is a large
non-gaussian contribution to the primordial power spectrum. This fact motivates
the re-analysis of the curvaton scenario, paying special attention to the
compatibility of large non-gaussianity of the local type with the current
detection limits on the isocurvature amplitude in the CMB. We find that if the
curvaton mechanism generates a primordial power spectrum with an important
non-gaussian component, any residual isocurvature imprint originated by the
curvaton, would have an amplitude too big to be compatible with the current
bounds. This implies that the isocurvature mode should be equal to zero in this
scenario and we explore the consequences of this inference. In order to prevent
the generation of a such a signal, the CDM must be created at a late stage,
after the curvaton decays completely. This requirement is used to constrain the
nature of the CDM in this scenario, arriving at a general relation between the
temperature of the universe at CDM creation and the scale of inflation.


title: Hybrid Quantum Gowdy Cosmology: Combining Loop and Fock Quantizations

abstract:
  We quantize an inhomogeneous cosmological model using techniques that include
polymeric quantization. More explicitly, we construct well defined operators to
represent the constraints and find the physical Hilbert space formed by their
solutions, which reproduces the conventional Fock quantization for the
inhomogeneities. The initial singularity is resolved in this inhomogeneous
model in an extremely simple way and without imposing special boundary
conditions, thus ensuring the robustness and generality of this resolution.
Furthermore this quantization constitutes a well founded step towards the
extraction of physical results and consequences from loop quantum cosmology,
given the central role of the inhomogeneities in modern cosmology.


title: Oscillations in the GSI electron capture experiment

abstract:
  In a recent paper, oscillations observed in the electron capture probability
were attributed to the mixing of neutrino mass eigenstates. This paper is shown
to be in error in two respects.


title:
Integral field spectroscopy of protoplanetary disks in Orion with VLT
  FLAMES

abstract:
  We discuss integral field spectroscopy of proplyds in M42 using the FLAMES
Argus unit and report the first detection of recombination lines of C II and O
II from the archetypical Laques-Vidal-2 object. These lines can provide
important new diagnostics of the physical conditions in proplyds. We also draw
attention to the future capabilities of the MUSE spectrograph in relation to
similar studies.


title:
Mg II h + k emission lines as stellar activity indicators of main
  sequence F-K stars

abstract:
  The main purpose of this study is to use the IUE spectra in the analysis of
magnetic activity of main sequence F-K stars. Combining IUE observations of
MgII and optical spectroscopy of Ca II, the registry of ctivity of stars can be
extended in time. We retrieved all the high-resolution spectra of F, G, and K
main sequence stars observed by IUE (i.e. 1623 spectra of 259 F to K dwarf
stars). We obtained the continuum surface flux near the Mg II h+k lines near
2800 \AA and the MgII line-core surface flux from the IUE spectra. We obtained
a relation between the mean continuum flux near the MgII lines with the colour
$B-V$ of the star. For a set of 117 nearly simultaneous observations of Mg II
and Ca II fluxes of 21 F5 to K3 main sequence stars, we obtained a colour
dependent relation between the Mount Wilson CaII S-index and the MgII emission
line-core flux. As an application of this calibration, we computed the Mount
Wilson index for all the dF to dK stars which have high resolution IUE spectra.
For some of the most frequently observed main sequence stars, we analysed the
Mount Wilson index S from the IUE spectra, together with the ones derived from
visible spectra. We confirm the cyclic chromospheric activity of epsilon Eri
(HD 22049) and beta Hydri (HD 2151), and we find a magnetic cycle in alpha Cen
B (HD 128621). Complete abstract in the paper.


title: Star formation efficiency in galaxy clusters

abstract:
  The luminous material in clusters of galaxies falls primarily into two forms:
the visible galaxies and the X-ray emitting intra-cluster medium. The hot
intra-cluster gas is the major observed baryonic component of clusters, about
six times more massive than the stellar component. The mass contained within
visible galaxies amounts to approximately 3% of the dynamical mass. Our aim was
to analyze both baryonic components, combining X-ray and optical data of a
sample of five galaxy clusters (Abell 496, 1689, 2050, 2631 and 2667), within
the redshift range 0.03 < z < 0.3. We determined the contribution of stars in
galaxies and the intra-cluster medium to the total baryon budget. We used
public XMM-Newton data to determine the gas mass and to obtain the X-ray
substructures. Using the optical counterparts from SDSS or CFHT we determined
the stellar contribution. We examine the relative contribution of galaxies,
intra-cluster light and intra-cluster medium to baryon budget in clusters
through the stellar-to-gas mass ratio, estimated with use of recent data. We
find that the stellar-to-gas mass ratio within r_500 (the radius which the mean
cluster density exceeds the critical density by a factor of 500), is
anti-correlated with the ICM temperature, ranging from 24% to 6% whereas the
temperature ranges from 4.0 to 8.3 keV. This indicates that less massive cold
clusters are more prolific star forming environments than massive hot clusters.


title:
The globally stable solution of a stochastic Nonlinear Schrodinger
  Equation

abstract:
  Weak measurement of a subset of noncommuting observables of a quantum system
can be modeled by the open-system evolution, governed by the master equation in
the Lindblad form. The open-system density operator can be represented as
statistical mixture over non unitarily evolving pure states, driven by the
stochastic Nonlinear Schrodinger equation (sNLSE). The globally stable solution
of the sNLSE is obtained in the case where the measured subset of observables
comprises the spectrum-generating algebra of the system. This solution is a
generalized coherent state (GCS), associated with the algebra. The result is
based on proving that GCS minimize the trace-norm of the covariance matrix,
associated with the spectrum-generating algebra.


title: Sensitivity of complex networks measurements

abstract:
  Complex networks obtained from the real-world networks are often
characterized by incompleteness and noise, consequences of limited sampling as
well as artifacts in the acquisition process. Because the characterization,
analysis and modeling of complex systems underlain by complex networks are
critically affected by the quality of the respective initial structures, it
becomes imperative to devise methodologies for identifying and quantifying the
effect of such sampling problems on the characterization of complex networks.
Given that several measurements need to be applied in order to achieve a
comprehensive characterization of complex networks, it is important to
investigate the effect of incompleteness and noise on such quantifications. In
this article we report such a study, involving 8 different measurements applied
on 6 different complex networks models. We evaluate the sensitiveness of the
measurements to perturbations in the topology of the network considering the
relative entropy. Three particularly important types of progressive
perturbations to the network are considered: edge suppression, addition and
rewiring. The conclusions have important practical consequences including the
fact that scale-free structures are more robust to perturbations. The
measurements allowing the best balance of stability (smaller sensitivity to
perturbations) and discriminability (separation between different network
topologies) were also identified.


title: Perturbative exponential expansion and matter neutrino oscillations

abstract:
  We derive an analytical description of neutrino oscillations in matter based
on the Magnus exponential representation of the time evolution operator. Our
approach is valid in a wide range of the neutrino energies and properly
accounts for the modifications that the respective probability transitions
suffer when neutrinos originated in different sources traverse the Earth. The
present approximation considerably improves over other perturbative treatments
existing in the current literature. Furthermore, the analytical expressions
derived inside the Magnus framework are remarkably simple, which facilitates
their practical use. When applied to the calculation of the day-night asymmetry
in the solar neutrino flux our result reproduces the numerical calculation with
an accuracy better than 1% for the first order approximation. When the
approximation is extended to the second order, the accuracy of the method is
further improved by almost one order of magnitude, and it is still better than
5% even for neutrino energies as large as 100 MeV. In the GeV regime
characteristic of atmospheric and accelerator neutrinos this accuracy is
complemented by a good reproduction of the position of the maxima in the flavor
transition probabilities.


title: Perturbations of rational Misiurewicz maps

abstract:
  In this paper we investigate the perturbation properties of rational
Misiurewicz maps, when the Julia set is the whole sphere (the other case is
treated in [1]). In particular, we show that if f is a Misiurewicz map and not
a flexible Lattes map, then we can find a hyperbolic map arbitrarily close to
f.


title:
Measurement of the differential cross section for the production of an
  isolated photon with associated jet in ppbar collisions at sqrt(s)=1.96 TeV

abstract:
  The process ppbar -> photon + jet + X is studied using 1.0 fb^-1 of data
collected by the D0 detector at the Fermilab Tevatron ppbar collider at a
center-of-mass energy sqrt(s)=1.96 TeV. Photons are reconstructed in the
central rapidity region |y_gamma|<1.0 with transverse momenta in the range
30<Pt_gamma<400 GeV while jets are reconstructed in either the central
|y_jet|<0.8 or forward 1.5<|y_jet|<2.5 rapidity intervals with Pt_jet>15 GeV.
The differential cross section d^3sigma/dPt_gamma dy_gamma dy_jet is measured
as a function of Pt_gamma in four regions, differing by the relative
orientations of the photon and the jet in rapidity. Ratios between the
differential cross sections in each region are also presented. Next-to-leading
order QCD predictions using different parameterizations of parton distribution
functions and theoretical scale choices are compared to the data. The
predictions do not simultaneously describe the measured normalization and
Pt_gamma dependence of the cross section in any of the four measured regions.


title: A fractional Poisson equation: existence, regularity and approximations

abstract:
  We consider a stochastic boundary value elliptic problem on a bounded domain
$D\subset \mathbb{R}^k$, driven by a fractional Brownian field with Hurst
parameter $H=(H_1,...,H_k)\in[{1/2},1[^k$. First we define the stochastic
convolution derived from the Green kernel and prove some properties. Using
monotonicity methods, we prove existence and uniqueness of solution, along with
regularity of the sample paths. Finally, we propose a sequence of lattice
approximations and prove its convergence to the solution of the SPDE at a given
rate.


title: Classical and Quantum Algorithms for Exponential Congruences

abstract:
  We discuss classical and quantum algorithms for solvability testing and
finding integer solutions x,y of equations of the form af^x + bg^y = c over
finite fields GF(q). A quantum algorithm with time complexity q^(3/8) (log
q)^O(1) is presented. While still superpolynomial in log q, this quantum
algorithm is significantly faster than the best known classical algorithm,
which has time complexity q^(9/8) (log q)^O(1). Thus it gives an example of a
natural problem where quantum algorithms provide about a cubic speed-up over
classical ones.


title: Undestanding Baseball Team Standings and Streaks

abstract:
  Can one understand the statistics of wins and losses of baseball teams? Are
their consecutive-game winning and losing streaks self-reinforcing or can they
be described statistically? We apply the Bradley-Terry model, which
incorporates the heterogeneity of team strengths in a minimalist way, to answer
these questions. Excellent agreement is found between the predictions of the
Bradley-Terry model and the rank dependence of the average number team wins and
losses in major-league baseball over the past century when the distribution of
team strengths is taken to be uniformly distributed over a finite range. Using
this uniform strength distribution, we also find very good agreement between
model predictions and the observed distribution of consecutive-game team
winning and losing streaks over the last half-century; however, the agreement
is less good for the previous half-century. The behavior of the last
half-century supports the hypothesis that long streaks are primarily
statistical in origin with little self-reinforcing component. The data further
show that the past half-century of baseball has been more competitive than the
preceding half-century.


title: First colonization of a hard-edge in random matrix theory

abstract:
  We describe the spectral statistics of the first finite number of eigenvalues
in a newly-forming band on the hard-edge of the spectrum of a random Hermitean
matrix model. It is found that in a suitable scaling regime, they are described
by the same spectral statistics of a finite-size Laguerre-type matrix model.
The method is rigorously based on the Riemann-Hilbert analysis of the
corresponding orthogonal polynomials.


title:
Inverted neutrino mass hierarchy and new signals of a chromophobic
  charged Higgs at the Large Hadron Collider

abstract:
  We explore the signals of a charged Higgs arising in a two Higgs doublet
model respecting SU(2)_L times U(1) times Z_2 symmetry with three singlet right
handed neutrinos, N_R. The charged Higgs in this model has negligible coupling
with quarks, and has unsuppressed coupling to leptons and neutrinos. This leads
to novel signatures of the charged Higgs at the LHC, especially in the case of
an inverted neutrino mass hierarchy, in the form of electrons and muons with
missing energy.


title: A minimal two-band model for the superconducting Fe-pnictides

abstract:
  Following the discovery of the Fe-pnictide superconductors, LDA band
structure calculations showed that the dominant contributions to the spectral
weight near the Fermi energy came from the Fe 3d orbitals. The Fermi surface is
characterized by two hole surfaces around the $\Gamma$ point and two electron
surfaces around the M point of the 2 Fe/cell Brillouin zone. Here, we describe
a 2-band model that reproduces the topology of the LDA Fermi surface and
exhibits both ferromagnetic and $q=(\pi,0)$ spin density wave (SDW)
fluctuations. We argue that this minimal model contains the essential low
energy physics of these materials.


title: Membranes on an Orbifold

abstract:
  We harvest clues to aid with the interpretation of the recently discovered
N=8 supersymmetric Chern-Simons theory with SO(4) gauge symmetry. The theory is
argued to describe two membranes moving in the orbifold R8/Z2. At level k=1 and
k=2, the classical moduli space M coincides with the infra-red moduli space of
SO(4) and SO(5) super Yang-Mills theory respectively. For higher Chern-Simons
level, the moduli space is a quotient of M. At a generic point in the moduli
space, the massive spectrum is proportional to the area of the triangle formed
by the two membranes and the orbifold fixed point.


title: Adaptive Dynamics of Realistic Small-World Networks

abstract:
  Continuing in the steps of Jon Kleinberg's and others celebrated work on
decentralized search in small-world networks, we conduct an experimental
analysis of a dynamic algorithm that produces small-world networks. We find
that the algorithm adapts robustly to a wide variety of situations in realistic
geographic networks with synthetic test data and with real world data, even
when vertices are uneven and non-homogeneously distributed.
  We investigate the same algorithm in the case where some vertices are more
popular destinations for searches than others, for example obeying power-laws.
We find that the algorithm adapts and adjusts the networks according to the
distributions, leading to improved performance. The ability of the dynamic
process to adapt and create small worlds in such diverse settings suggests a
possible mechanism by which such networks appear in nature.


title:
Clonal Interference, Multiple Mutations, and Adaptation in Large Asexual
  Populations

abstract:
  Two important problems affect the ability of asexual populations to
accumulate beneficial mutations, and hence to adapt. First, clonal interference
causes some beneficial mutations to be outcompeted by more-fit mutations which
occur in the same genetic background. Second, multiple mutations occur in some
individuals, so even mutations of large effect can be outcompeted unless they
occur in a good genetic background which contains other beneficial mutations.
In this paper, we use a Monte Carlo simulation to study how these two factors
influence the adaptation of asexual populations. We find that the results
depend qualitatively on the shape of the distribution of the effects of
possible beneficial mutations. When this distribution falls off slower than
exponentially, clonal interference alone reasonably describes which mutations
dominate the adaptation, although it gives a misleading picture of the
evolutionary dynamics. When the distribution falls off faster than
exponentially, an analysis based on multiple mutations is more appropriate.
Using our simulations, we are able to explore the limits of validity of both of
these approaches, and we explore the complex dynamics in the regimes where
neither are fully applicable.


title: Network Beamforming Using Relays with Perfect Channel Information

abstract:
  This paper is on beamforming in wireless relay networks with perfect channel
information at relays, the receiver, and the transmitter if there is a direct
link between the transmitter and receiver. It is assumed that every node in the
network has its own power constraint. A two-step amplify-and-forward protocol
is used, in which the transmitter and relays not only use match filters to form
a beam at the receiver but also adaptively adjust their transmit powers
according to the channel strength information. For a network with any number of
relays and no direct link, the optimal power control is solved analytically.
The complexity of finding the exact solution is linear in the number of relays.
Our results show that the transmitter should always use its maximal power and
the optimal power used at a relay is not a binary function. It can take any
value between zero and its maximum transmit power. Also, this value depends on
the quality of all other channels in addition to the relay's own channels.
Despite this coupling fact, distributive strategies are proposed in which, with
the aid of a low-rate broadcast from the receiver, a relay needs only its own
channel information to implement the optimal power control. Simulated
performance shows that network beamforming achieves the maximal diversity and
outperforms other existing schemes. Then, beamforming in networks with a direct
link are considered. We show that when the direct link exists during the first
step only, the optimal power control is the same as that of networks with no
direct link. For networks with a direct link during the second step, recursive
numerical algorithms are proposed to solve the power control problem.
Simulation shows that by adjusting the transmitter and relays' powers
adaptively, network performance is significantly improved.


title: A Survey of Quantum Programming Languages: History, Methods, and Tools

abstract:
  Quantum computer programming is emerging as a new subject domain from
multidisciplinary research in quantum computing, computer science, mathematics
(especially quantum logic, lambda calculi, and linear logic), and engineering
attempts to build the first non-trivial quantum computer. This paper briefly
surveys the history, methods, and proposed tools for programming quantum
computers circa late 2007. It is intended to provide an extensive but
non-exhaustive look at work leading up to the current state-of-the-art in
quantum computer programming. Further, it is an attempt to analyze the needed
programming tools for quantum programmers, to use this analysis to predict the
direction in which the field is moving, and to make recommendations for further
development of quantum programming language tools.


title: Theories of bundles with additional homotopy conditions

abstract:
  In the present paper we study bundles equipped with extra homotopy
conditions, in particular so-called simplicial $n$-bundles. It is shown that
(under some condition) the classifying space of 1-bundles is the double coset
space of some finite dimensional Lie group. We also establish some relation
between our bundles and C*-algebras.


title: New Anomalies in Topological String Theory

abstract:
  We show that the topological string partition function with D-branes on a
compact Calabi-Yau manifold has new anomalies that spoil the recursive
structure of the holomorphic anomaly equation and introduce dependence on wrong
moduli (such as complex structure moduli in the A-model), unless the disk
one-point functions vanish. This provides a microscopic explanation for the
recent result of Walcher in arXiv:0712.2775 on counting of BPS states in
M-theory using the topological string partition function. The relevance of
vanishing disk one-point functions to large $N$ duality for compact Calabi-Yau
manifolds is noted.


title: Neutrino Oscillation Phenomenology

abstract:
  We explain the physics of neutrino oscillation in vacuum and in matter. We
attempt to clarify several features of oscillation that can be puzzling when
neutrinos are their own antiparticles.


title:
Cluster AgeS Experiment (CASE): Deficiency of observed dwarf novae in
  globular clusters

abstract:
  We present the results of a search for dwarf novae (DNe) in globular clusters
(GCs). It is based on the largest available homogeneous sample of observations,
in terms of the time span, number of observations and number of clusters. It
includes 16 Galactic GCs and yielded two new certain DNe: M55-CV1 and M22-CV2.
All previously known systems located in our fields were recovered, too. We
surveyed M4, M5, M10, M12, M22, M30, M55, NGC 288, NGC 362, NGC 2808, NGC 3201,
NGC 4372, NGC 6362, NGC 6752, omega Cen (NGC 5139) and 47 Tuc (NGC 104). The
discovery of two DNe, namely M55-CV1 and M22-CV2, was already reported by
Kaluzny et al. (2005) and Pietrukowicz et al. (2005), respectively. In the
remaining 14 GCs we found no certain new DNe. Our result raises the total
number of known DNe in the Galactic globular clusters to 12 DNe, distributed
among 7 clusters. Our survey recovered all three already known erupting
cataclysmic variables (CVs) located in our fields, namely M5-V101, M22-CV1, and
V4 in the foreground of M30. To assess the efficiency of the survey, we
analyzed images with inserted artificial stars mimicking outbursts of the
prototype dwarf novae SS Cyg and U Gem. Depending on the conditions, we
recovered between 16-100 percent of these artificial stars. The efficiency
seems to be predominantly affected by duty cycle/time sampling and much less by
distance/magnitude. Except for saturated tiny collapsed cores of M30, NGC 362
and NGC 6752 (and also the dense core of NGC 2808) crowding effects in the V
band were avoided by our image subtraction technique augmented with auxiliary
unsaturated B-band images. Our results clearly demonstrate that in GCs common
types of DNe are very rare indeed. However, great care must be taken before
these conclusions can be extended to the CV population in GCs.


title:
Probing Shock Breakout with Serendipitous GALEX Detections of Two SNLS
  Type II-P Supernovae

abstract:
  We report the serendipitous detection by GALEX of fast (<1 day) rising (>1
mag) UV emission from two Type II plateau (II-P) supernovae (SNe) at z=0.185
and 0.324 discovered by the Supernova Legacy Survey. Optical photometry and VLT
spectroscopy 2 weeks after the GALEX detections link the onset of UV emission
to the time of shock breakout. Using radiation hydrodynamics and non-LTE
radiative transfer simulations, and starting from a standard red supergiant
(RSG; Type II-P SN progenitor) star evolved self-consistently from the main
sequence to iron core collapse, we model the shock breakout phase and the 55 hr
that follow. The small scale height of our RSG atmosphere model suggests that
the breakout signature is a thermal soft X-ray burst (lambda_peak ~ 90\AA) with
a duration of <~ 2000 s. Longer durations are possible but require either an
extended and tenuous non-standard envelope, or an unusually dense RSG wind with
\dot{M} ~ 10^(-3) Msun yr^(-1). The GALEX observations miss the peak of the
luminous (M_FUV ~ -20) UV burst but unambiguously capture the rise of the
emission and a subsequent 2 day long plateau. The postbreakout, UV-bright
plateau is a prediction of our model in which the shift of the peak of the
spectral energy distribution (SED) from ~100 to ~1000\AA and the ejecta
expansion both counteract the decrease in bolometric luminosity from ~10^11 to
~10^9 L_sun over that period. Based on the observed detection efficiency of our
study we make predictions for the breakout detection rate of the GALEX Time
Domain Survey.


title:
Characterization of minimal-mass blowup solutions to the focusing
  mass-critical NLS

abstract:
  Let $d\geq 4$ and let $u$ be a global solution to the focusing mass-critical
nonlinear Schr\"odinger equation $iu_t+\Delta u=-|u|^{\frac 4d}u$ with
spherically symmetric $H_x^1$ initial data and mass equal to that of the ground
state $Q$. We prove that if $u$ does not scatter then, up to phase rotation and
scaling, $u$ is the solitary wave $e^{it}Q$. Combining this result with that of
Merle \cite{merle2}, we obtain that in dimensions $d\geq 4$, the only
spherically symmetric minimal-mass blowup solutions are, up to phase rotation
and scaling, the pseudo-conformal ground state and the solitary wave.


title:
N-ification of Forces: A Holographic Perspective on D-brane Model
  Building

abstract:
  We study geometric aspects of extensions of the supersymmetric standard model
that exhibit a periodic duality cascade. Via the holographic correspondence,
the growth of the gauge group rank towards the UV is interpreted as a gradual
decompactification transition. We show that this class of models typically
develop a duality wall in the UV, and present an efficient method for
estimating the hierarchy between the on-set of the cascade and the formation of
the wall. As an illustrative example, we study the model introduced by
Cascales, Saad and Uranga in [14], which has an known geometric realization in
terms of D-branes on an SPP/Z_3 singularity.


title: Target atmospheric CO2: Where should humanity aim?

abstract:
  Paleoclimate data show that climate sensitivity is ~3 deg-C for doubled CO2,
including only fast feedback processes. Equilibrium sensitivity, including
slower surface albedo feedbacks, is ~6 deg-C for doubled CO2 for the range of
climate states between glacial conditions and ice-free Antarctica. Decreasing
CO2 was the main cause of a cooling trend that began 50 million years ago,
large scale glaciation occurring when CO2 fell to 450 +/- 100 ppm, a level that
will be exceeded within decades, barring prompt policy changes. If humanity
wishes to preserve a planet similar to that on which civilization developed and
to which life on Earth is adapted, paleoclimate evidence and ongoing climate
change suggest that CO2 will need to be reduced from its current 385 ppm to at
most 350 ppm. The largest uncertainty in the target arises from possible
changes of non-CO2 forcings. An initial 350 ppm CO2 target may be achievable by
phasing out coal use except where CO2 is captured and adopting agricultural and
forestry practices that sequester carbon. If the present overshoot of this
target CO2 is not brief, there is a possibility of seeding irreversible
catastrophic effects.


title:
Tests of Relativistic Gravity in Space: Recent Progress and Future
  Directions

abstract:
  We review the foundations of Einstein's general theory of relativity, discuss
recent progress in the tests of relativistic gravity, and present motivations
for new generation of high-accuracy gravitational experiments. We discuss the
advances in our understanding of fundamental physics anticipated in the near
future and evaluate discovery potential of the recently proposed gravitational
experiments.


title: Metallicities & Activities of Southern Stars

abstract:
  We present the results from high-resolution spectroscopic measurements to
determine metallicities and activities of bright stars in the southern
hemisphere. We have measured the iron abundances ([Fe/H]) and chromospheric
emission indices (logR'HK) of 353 solar-type stars with V=7.5-9.5. [Fe/H]
abundances are determined using a custom chi^2 fitting procedure within a large
grid of Kurucz model atmospheres. The chromospheric activities were determined
by measuring the amount of emission in the cores of the strong CaII HK lines.
The sample of metallicities has been compared to other [Fe/H] determinations
and was found to agree with these at the +/-0.05 dex level for spectroscopic
values and at the +/-0.1 dex level for photometric values. The distribution of
chromospheric activities is found to be described by a bimodal distribution,
agreeing well with the conclusions from other works. Also an analysis of
Maunder Minimum status was attempted and it was found that 6+/-4 stars in the
sample could be in a Maunder Minimum phase of their evolution and hence the Sun
should only spend a few per cent of its main sequence lifetime in Maunder
Minimum.


title: Dynamically broken Anti-de Sitter action for gravity

abstract:
  Due to a suitable Higgs mechanism, a standard Anti-de Sitter gauge theory
becomes spontaneously broken. The resulting Lorentz invariant gravitational
action includes the Hilbert-Einstein term of ordinary Einstein-Cartan gravity
with cosmological constant, plus contributions quadratic in curvature and
torsion, and a scalar Higgs sector.


title: Foreground simulations for the LOFAR - Epoch of Reionization Experiment

abstract:
  Future high redshift 21-cm experiments will suffer from a high degree of
contamination, due both to astrophysical foregrounds and to non-astrophysical
and instrumental effects. In order to reliably extract the cosmological signal
from the observed data, it is essential to understand very well all data
components and their influence on the extracted signal. Here we present
simulated astrophysical foregrounds datacubes and discuss their possible
statistical effects on the data. The foreground maps are produced assuming 5
deg x 5 deg windows that match those expected to be observed by the LOFAR
Epoch-of-Reionization (EoR) key science project. We show that with the expected
LOFAR-EoR sky and receiver noise levels, which amount to ~52 mK at 150 MHz
after 300 hours of total observing time, a simple polynomial fit allows a
statistical reconstruction of the signal. We also show that the polynomial
fitting will work for maps with realistic yet idealised instrument response,
i.e., a response that includes only a uniform uv coverage as a function of
frequency and ignores many other uncertainties. Polarized galactic synchrotron
maps that include internal polarization and a number of Faraday screens along
the line of sight are also simulated. The importance of these stems from the
fact that the LOFAR instrument, in common with all current interferometric EoR
experiments has an instrumentally polarized response.


title: The closed string tadpole in open string field theory

abstract:
  We compute a class of gauge invariant observables for marginal solutions and
the tachyon vacuum. In each case we find that the observables are related in a
simple way to the closed-string tadpole on a disk with appropriate boundary
conditions. We give a sketch of an argument that this result should hold in
general using the BRST invariance of the closed string two-point function.
Finally, we discuss the analogous set of invariants in the Berkovits
superstring field theory.


title: Geometrically Engineerable Chiral Matter in M-Theory

abstract:
  We present a classification of the massless chiral matter representations
that can arise locally in M-theory on G(2) through geometrically engineered
singularities. We will find that several of the more exceptional singularities
could have applications for model building.


title: Prospective Algorithms for Quantum Evolutionary Computation

abstract:
  This effort examines the intersection of the emerging field of quantum
computing and the more established field of evolutionary computation. The goal
is to understand what benefits quantum computing might offer to computational
intelligence and how computational intelligence paradigms might be implemented
as quantum programs to be run on a future quantum computer. We critically
examine proposed algorithms and methods for implementing computational
intelligence paradigms, primarily focused on heuristic optimization methods
including and related to evolutionary computation, with particular regard for
their potential for eventual implementation on quantum computing hardware.


title:
Coarse Grained Modeling of The Interface Between Water and Heterogeneous
  Surfaces

abstract:
  Using coarse grained models we investigate the behavior of water adjacent to
an extended hydrophobic surface peppered with various fractions of hydrophilic
patches of different sizes. We study the spatial dependence of the mean
interface height, the solvent density fluctuations related to drying the patchy
substrate, and the spatial dependence of interfacial fluctuations. We find that
adding small uniform attractive interactions between the substrate and solvent
cause the mean position of the interface to be very close to the substrate.
Nevertheless, the interfacial fluctuations are large and spatially
heterogeneous in response to the underlying patchy substrate. We discuss the
implications of these findings to the assembly of heterogeneous surfaces.


title: Target atmospheric CO2: Supporting material

abstract:
  Additional material supporting the article "Target atmospheric CO2: Where
should humanity aim?"


title: Quantum ergodicity and entanglement in kicked coupled-tops

abstract:
  We study the dynamical generation of entanglement as a signature of chaos in
a system of periodically kicked coupled-tops, where chaos and entanglement
arise from the same physical mechanism. The long-time averaged entanglement as
a function of the position of an initially localized wave packet very closely
correlates with the classical phase space surface of section -- it is nearly
uniform in the chaotic sea, and reproduces the detailed structure of the
regular islands. The uniform value in the chaotic sea is explained by the
random state conjecture. As classically chaotic dynamics take localized
distributions in phase space to random distributions, quantized versions take
localized coherent states to pseudo-random states in Hilbert space. Such random
states are highly entangled, with an average value near that of the maximally
entangled state. For a map with global chaos, we derive that value based on new
analytic results for the typical entanglement in a subspace defined by the
symmetries of the system.
  For a mixed phase space, we use the Percival conjecture to identify a
"chaotic subspace" of the Hilbert space. The typical entanglement, averaged
over the unitarily invariant Haar measure in this subspace, agrees with the
long-time averaged entanglement for initial states in the chaotic sea. In all
cases the dynamically generated entanglement is predicted by a unitary ensemble
of random states, even though the system is time-reversal invariant, and the
Floquet operator is a member of the circular orthogonal ensemble.


title: Variational assimilation of Lagrangian data in oceanography

abstract:
  We consider the assimilation of Lagrangian data into a primitive equations
circulation model of the ocean at basin scale. The Lagrangian data are
positions of floats drifting at fixed depth. We aim at reconstructing the
four-dimensional space-time circulation of the ocean. This problem is solved
using the four-dimensional variational technique and the adjoint method. In
this problem the control vector is chosen as being the initial state of the
dynamical system. The observed variables, namely the positions of the floats,
are expressed as a function of the control vector via a nonlinear observation
operator. This method has been implemented and has the ability to reconstruct
the main patterns of the oceanic circulation. Moreover it is very robust with
respect to increase of time-sampling period of observations. We have run many
twin experiments in order to analyze the sensitivity of our method to the
number of floats, the time-sampling period and the vertical drift level. We
compare also the performances of the Lagrangian method to that of the classical
Eulerian one. Finally we study the impact of errors on observations.


title:
Resonant Spin Polarization and Hall Effects in a Two-Dimensional
  Electron Gas

abstract:
  We have studied transport properties in a two-dimensional electron gas with
equal Rashba and Dresselhaus spin-orbit interactions under a perpendicular
magnetic field. By employing the exact solution for this system, we found
resonant charge and spin Hall conductances at a certain magnetic field, where
all the nearest-neighboring Landau levels cross. Near this value of magnetic
field, there exists a resonant spin polarization, which can also induce
resonant charge and spin Hall effects.


title:
Optimal control of the Primitive Equations of the Ocean with Lagrangian
  observations

abstract:
  We consider an optimal control problem for the three-dimensional non-linear
Primitive Equations of the ocean in a vertically bounded and horizontally
periodic domain. The observation operator maps a solution of the Primitive
Equations to the trajectory of a Lagrangian particle. This paper proves the
existence of an optimal control for the regularized problem. To do that, we
prove also new energy estimates for the Primitive Equations, thanks to
well-chosen functional spaces, which distinguish the vertical dimension from
the horizontal ones. We illustrate the result with a numerical experiment.


title: Maximal vectors in Hilbert space and quantum entanglement

abstract:
  Let $V$ be a norm-closed subset of the unit sphere of a Hilbert space $H$
that is stable under multiplication by scalars of absolute value 1. A {\em
maximal vector} (for $V$) is a unit vector $\xi\in H$ whose distance to $V$ is
maximum $d(\xi,V)=\sup_{\|\eta\|=1}d(\eta,V)$, $d(\xi,V)$ denoting the distance
from $\xi$ to the set $V$. Maximal vectors generalize the {\em maximally
entangled} unit vectors of quantum theory.
  In general, under a mild regularity hypothesis on $V$, there is a {\em norm}
on $H$ whose restriction to the unit sphere achieves its minimum precisely on
$V$ and its maximum precisely on the set of maximal vectors. This
"entanglement-measuring norm" is unique. There is a corresponding
"entanglement-measuring norm" on the predual of $\mathcal B(H)$ that faithfully
detects entanglement of normal states.
  We apply these abstract results to the analysis of entanglement in
multipartite tensor products $H=H_1\otimes ...\otimes H_N$, and we calculate
both entanglement-measuring norms. In cases for which $\dim H_N$ is relatively
large with respect to the others, we describe the set of maximal vectors in
explicit terms and show that it does not depend on the number of factors of the
Hilbert space $H_1\otimes...\otimes H_{N-1}$.


title:
A new probe of magnetic fields during high-mass star formation: Zeeman
  splitting of 6.7 GHz methanol masers

abstract:
  Context: The role of magnetic fields during high-mass star formation is a
matter of fierce debate, yet only a few direct probes of magnetic field
strengths are available.
  Aims: The magnetic field is detected in a number of massive star-forming
regions through polarization observations of 6.7 GHz methanol masers. Although
these masers are the most abundant of the maser species occurring during
high-mass star formation, most magnetic field measurements in the high-density
gas currently come from OH and H2 O maser observations.
  Methods: The 100-m Effelsberg telescope was used to measure the Zeeman
splitting of 6.7 GHz methanol masers for the first time. The observations were
performed on a sample of 24 bright northern maser sources.
  Results: Significant Zeeman splitting is detected in 17 of the sources with
an average magnitude of 0.56 m/s . Using the current best estimate of the 6.7
GHz methanol maser Zeeman splitting coefficient and a geometrical correction,
this corresponds to an absolute magnetic field strength of 23 mG in the
methanol maser region.
  Conclusions: The magnetic field is dynamically important in the dense maser
regions. No clear relation is found with the available OH maser magnetic field
measurements. The general sense of direction of the magnetic field is
consistent with other Galactic magnetic field measurements, although a few of
the masers display a change of direction between different maser features. Due
to the abundance of methanol masers, measuring their Zeeman splitting provides
the opportunity to construct a comprehensive sample of magnetic fields in
high-mass star-forming regions.


title: The muon g-2 and the bounds on the Higgs boson mass

abstract:
  After a brief review of the muon g-2 status, we analyze the possibility that
the present discrepancy between experiment and the Standard Model (SM)
prediction may be due to hypothetical errors in the determination of the
hadronic leading-order contribution to the latter. In particular, we show how
an increase of the hadro-production cross section in low-energy e^+e^-
collisions could bridge the muon g-2 discrepancy, leading however to a decrease
on the electroweak upper bound on M_H, the SM Higgs boson mass. That bound is
currently M_H < ~ 150GeV (95%CL) based on the preliminary top quark mass M_t =
172.6(1.4)GeV and the recent determination \Delta \alpha_{\rm had}^{(5)}(M_Z) =
0.02768(22), while the direct-search lower bound is M_H > 114.4GeV (95%CL). By
means of a detailed analysis we conclude that this solution of the muon g-2
discrepancy is unlikely in view of current experimental error estimates.
However, if this turns out to be the solution, the 95%CL upper bound on M_H is
reduced to about 130GeV which, in conjunction with the experimental lower
bound, leaves a narrow window for the mass of this fundamental particle.


title:
Sliced Inverse Moment Regression Using Weighted Chi-Squared Tests for
  Dimension Reduction

abstract:
  We propose a new method for dimension reduction in regression using the first
two inverse moments. We develop corresponding weighted chi-squared tests for
the dimension of the regression. The proposed method considers linear
combinations of Sliced Inverse Regression (SIR) and the method using a new
candidate matrix which is designed to recover the entire inverse second moment
subspace. The optimal combination may be selected based on the p-values derived
from the dimension tests. Theoretically, the proposed method, as well as Sliced
Average Variance Estimate (SAVE), are more capable of recovering the complete
central dimension reduction subspace than SIR and Principle Hessian Directions
(pHd). Therefore it can substitute for SIR, pHd, SAVE, or any linear
combination of them at a theoretical level. Simulation study indicates that the
proposed method may have consistently greater power than SIR, pHd, and SAVE.


title:
Signatures of Strong Correlations in One-Dimensional Ultra-Cold Atomic
  Fermi Gases

abstract:
  Recent success in manipulating ultra-cold atomic systems allows to probe
different strongly correlated regimes in one-dimension. Regimes such as the
(spin-coherent) Luttinger liquid and the spin-incoherent Luttinger liquid can
be realized by tuning the inter-atomic interaction strength and trap
parameters. We identify the noise correlations of density fluctuations as a
robust observable (uniquely suitable in the context of trapped atomic gases) to
discriminate between these two regimes. Finally, we address the prospects to
realize and probe these phenomena experimentally using optical lattices.


title: Search for Fermion Actions on Hyperdiamond Lattices

abstract:
  Fermions moving in a two-dimensional honeycomb lattice (graphene) have, at
low energies, chiral symmetry. Generalizing this construction to four
dimensions potentially provides fermions with chiral symmetry and only the
minimal fermion doubling demanded by the Nielsen-Ninomiya no-go theorem. The
practical usefulness of such fermions hinges on whether the action has a
necessary set of discrete symmetries of the lattice. If this is the case, one
avoids the generation of dimension three and four operators which require fine
tuning. We construct hyperdiamond lattice actions with enough symmetries to
exclude fine tuning; however, they produce multiple doublings. The limit where
the actions exhibit minimal doubling does not possess the requisite symmetry.


title: Reply to "Comment on "On a new definition of quantum entropy""

abstract:
  The example provided in the comment [arXiv:0803.2241] concerns a situation
where the system is initially at negative temperature. It is known that in such
cases the Law of Entropy Decrease holds. Nevertheless, this does not challenge
the validity of the Second Law of Thermodynamics.


title:
New Indicators for AGN Power: The Correlation Between [O IV] lambda
  25.89 micron and Hard X-ray Luminosity for Nearby Seyfert Galaxies

abstract:
  We have studied the relationship between the [O IV] lambda 25.89 micron
emission line luminosities, obtained from Spitzer spectra, the X-ray continua
in the 2-10 keV band, primarily from ASCA, and the 14-195 keV band obtained
with the SWIFT/Burst Alert Telescope (BAT), for a sample of nearby (z < 0.08)
Seyfert galaxies. For comparison, we have examined the relationship between the
[O III] 5007, the 2-10 keV and the 14-195 keV luminosities for the same set of
objects. We find that both the [O IV] and [O III] luminosities are
well-correlated with the BAT luminosities. On the other hand, the [O III]
luminosities are better-correlated with 2-10 keV luminosities than are those of
[O IV]. When comparing [O IV] and [O III] luminosities for the different types
of galaxies, we find that the Seyfert 2's have significantly lower [O III] to
[O IV] ratios than the Seyfert 1's. We suggest that this is due to more
reddening of the narrow line region (NLR) of the Seyfert 2's. Assuming Galactic
dust to gas ratios, the average amount of extra reddening corresponds to a
hydrogen column density of ~ few times 10^21 cm^-2, which is a small fraction
of the X-ray absorbing columns in the Seyfert 2's. The combined effects of
reddening and the X-ray absorption are the probable reason why the [O III]
versus 2-10 keV correlation is better than the [O IV] versus 2-10 keV, since
the [O IV] emission line is much less affected by extinction. Overall, we find
the [O IV] to be an accurate and truly isotropic indicator of the power of the
AGN. This suggests that it can be useful in deconvolving the contribution of
the AGN and starburst to the spectrum of Compton-thick and/or X-ray weak
sources.


title: Theory of Activated Transport in Bilayer Quantum Hall Systems

abstract:
  We analyze the transport properties of bilayer quantum Hall systems at total
filling factor $\nu=1$ in drag geometries as a function of interlayer bias, in
the limit where the disorder is sufficiently strong to unbind meron-antimeron
pairs, the charged topological defects of the system. We compute the typical
energy barrier for these objects to cross incompressible regions within the
disordered system using a Hartree-Fock approach, and show how this leads to
multiple activation energies when the system is biased. We then demonstrate
using a bosonic Chern-Simons theory that in drag geometries, current in a
single layer directly leads to forces on only two of the four types of merons,
inducing dissipation only in the drive layer. Dissipation in the drag layer
results from interactions among the merons, resulting in very different
temperature dependences for the drag and drive layers, in qualitative agreement
with experiment.


title: Porto Oscillation Code (POSC)

abstract:
  The Porto Oscillation Code (POSC) has been developed in 1995 and improved
over the years, with the main goal of calculating linear adiabatic oscillations
for models of solar-type stars. It has also been used to estimate the
frequencies and eigenfunctions of stars from the pre-main sequence up to the
sub-giant phase, having a mass between 0.8 and 4 solar masses.
  The code solves the linearised perturbation equations of adiabatic pulsations
for an equilibrium model using a second order numerical integration method. The
possibility of using Richardson extrapolation is implemented. Several options
for the surface boundary condition can be used. In this work we briefly review
the key ingredients of the calculations, namely the equations, the numerical
scheme and the output.


title:
Predicting the Yields of Photometric Surveys for Transiting Extrasolar
  Planets

abstract:
  We develop a method for predicting the yield of transiting planets from a
photometric survey given the parameters of the survey (nights observed,
bandpass, exposure time, telescope aperture, locations of the target fields,
observational conditions, and detector characteristics), as well as the
underlying planet properties (frequency, period and radius distributions).
Using our updated understanding of transit surveys provided by the experiences
of the survey teams, we account for those factors that have proven to have the
greatest effect on the survey yields. Specifically, we include the effects of
the surveys' window functions, adopt revised estimates of the giant planet
frequency, account for the number and distribution of main-sequence stars in
the survey fields, and include the effects of Galactic structure and
interstellar extinction. We approximate the detectability of a planetary
transit using a signal-to-noise ratio (S/N) formulation. We argue that our
choice of detection criterion is the most uncertain input to our predictions,
and has the largest effect on the resulting planet yield. Thus drawing robust
inferences about the frequency of planets from transit surveys will require
that the survey teams impose and report objective, systematic, and quantifiable
detection criteria. Nevertheless, with reasonable choices for the minimum S/N,
we calculate yields that are generally lower, more accurate, and more realistic
than previous predictions. As examples, we apply our method to the
Trans-Atlantic Exoplanet Survey, the XO survey, and the {\it Kepler} mission.
We discuss red noise and its possible effects on planetary detections. We
conclude with estimates of the expected detection rates for future wide-angle
synoptic surveys.


title:
Inertial modes of rigidly rotating neutron stars in Cowling
  approximation

abstract:
  In this article, we investigate inertial modes of rigidly rotating neutron
stars, i.e. modes for which the Coriolis force is dominant. This is done using
the assumption of a fixed spacetime (Cowling approximation). We present
frequencies and eigenfunctions for a sequence of stars with a polytropic
equation of state, covering a broad range of rotation rates. The modes were
obtained with a nonlinear general relativistic hydrodynamic evolution code. We
further show that the eigenequations for the oscillation modes can be written
in a particularly simple form for the case of arbitrary fast, but rigid
rotation. Using these equations, we investigate some general characteristics of
inertial modes, which are then compared to the numerically obtained
eigenfunctions. In particular, we derive a rough analytical estimate for the
frequency as a function of the number of nodes of the eigenfunction, and find
that a similar empirical relation matches the numerical results with unexpected
accuracy. We investigate the slow rotation limit of the eigenequations,
obtaining two different sets of equations describing pressure and inertial
modes. For the numerical computations we only considered axisymmetric modes,
while the analytic part also covers nonaxisymmetric modes. The eigenfunctions
suggest that the classification of inertial modes by the quantum numbers of the
leading term of a spherical harmonic decomposition is artificial in the sense
that the largest term is not strongly dominant, even in the slow rotation
limit. The reason for the different structure of pressure and inertial modes is
that the Coriolis force remains important in the slow rotation limit only for
inertial modes. Accordingly, the scalar eigenequation we obtain in that limit
is spherically symmetric for pressure modes, but not for inertial modes.


title: New Black Holes in Five Dimensions

abstract:
  We construct new stationary Ricci-flat metrics of cohomogeneity 2 in five
dimensions, which generalise the Myers-Perry rotating black hole metrics by
adding a further non-trivial parameter. We obtain them via a construction that
is analogous to the construction by Plebanski and Demianski in four dimensions
of the most general type D metrics. Limiting cases of the new metrics contain
not only the general Myers-Perry black hole with independent angular momenta,
but also the single rotation black ring of Emparan and Reall. In another limit,
we obtain new static metrics that describe black holes whose horizons are
distorted lens spaces L(n;m)= S^3/\Gamma(n;m), where m\ge n+2\ge 3. They are
asymptotic to Minkowski spacetime factored by \Gamma(m;n). In the general
stationary case, by contrast, the new metrics describe spacetimes with an
horizon and with a periodicity condition on the time coordinate; these examples
can be thought of as five-dimensional analogues of the four-dimensional
Taub-NUT metrics.


title:
Groups of Operators for Evolution Equations of Quantum Many-Particle
  Systems

abstract:
  The aim of this work is to study the properties of groups of operators for
evolution equations of quantum many-particle systems, namely, the von Neumann
hierarchy for correlation operators, the BBGKY hierarchy for marginal density
operators and the dual BBGKY hierarchy for marginal observables. We show that
the concept of cumulants (semi-invariants) of groups of operators for the von
Neumann equations forms the basis of the expansions for one-parametric families
of operators for evolution equations of infinitely many particles.

categories: quant-ph cond-mat.stat-mech math-ph math.AP math.MP


title: On a generalized Sierpinski fractal in RP^n

abstract:
  We associate a fractal in $\RPn$ to each vector basis of $\bR^{n+1}$ and we
study its measure and asymptotic properties. Then we discuss and study
numerically in detail the cases $n=1,2,3$, evaluating in particular their
Hausdorff dimension.


title: Branching processes in random environment die slowly

abstract:
  Let $Z_{n,}n=0,1,...,$ be a branching process evolving in the random
environment generated by a sequence of iid generating functions $%
f_{0}(s),f_{1}(s),...,$ and let $S_{0}=0,S_{k}=X_{1}+...+X_{k},k\geq 1,$ be the
associated random walk with $X_{i}=\log f_{i-1}^{\prime}(1),$ $\tau (m,n)$ be
the left-most point of minimum of $\left\{S_{k},k\geq 0\right\} $ on the
interval $[m,n],$ and $T=\min \left\{k:Z_{k}=0\right\} $. Assuming that the
associated random walk satisfies the Doney condition $P(S_{n}>0) \to \rho \in
(0,1),n\to \infty ,$ we prove (under the quenched approach) conditional limit
theorems, as $n\to \infty $, for the distribution of $Z_{nt},$ $Z_{\tau
(0,nt)},$ and $Z_{\tau (nt,n)},$ $t\in (0,1),$ given $T=n$. It is shown that
the form of the limit distributions essentially depends on the location of
$\tau (0,n)$ with respect to the point $nt.$


title: Minimal Anomalous U(1)' Extension of the MSSM

abstract:
  We study an extension of the MSSM by an anomalous abelian vector multiplet
and a St\"uckelberg multiplet. The anomalies are cancelled by the Green-Schwarz
mechanism and the addition of Chern-Simons terms. The advantage of this choice
over the standard one is that it allows for arbitrary values of the quantum
numbers of the extra U(1). As a first step towards the study of hadron
annihilations producing four leptons in the final state (a clean signal which
might be studied at LHC) we then compute the decays $Z'\to Z_0 \g$ and $Z'\to
Z_0 Z_0$. We find that the largest values of the decay rate is $\sim 10^{-4}$
GeV, while the expected number of events per year at LHC is at most of the
order of 10.


title:
Onset of phase correlations in YBa2Cu3O{7-x} as determined from
  reversible magnetization measurements

abstract:
  Isofield magnetization curves are obtained and analyzed for three single
crystals of YBa2Cu3O{7-x}, ranging from optimally doped to very underdoped, as
well as the BCS superconductor Nb, in the presence of magnetic fields applied
both parallel and perpendicular to the $ab$ planes. Near Tc, the magnetization
exhibits a temperature dependence \sqrt{M} [Ta(H)-T]^m. In accordance with
recent theories, we associated Ta(H) with the onset of coherent phase
fluctuations of the superconducting order parameter. For Nb and optimally doped
YBaCuO, Ta(H) is essentially identical to the mean-field transition line Tc(H).
The fitting exponent m=0.5 takes its mean-field value for Nb, and varies just
slightly from 0.5 for optimally doped YBaCuO. However, underdoped YBCO samples
exhibit anomalous behavior, with Ta(H)>Tc for H applied parallel to the c axis,
suggesting that the magnetization is probing a region of temperatures above Tc
where phase correlations persist. In this region, the fitting exponent falls in
the range 0.5 < m < 0.8 for H\parallel c, compared with m~0. for $H\parallel ab
planes. The results are interpreted in terms of an anisotropic pairing symmetry
of the order parameter: d-wave along the ab planes and s-wave along the c axis.


title: Convergence of compact Ricci solitons

abstract:
  We show that sequences of compact gradient Ricci solitons converge to
complete orbifold gradient solitons, assuming constraints on volume, the
$L^{n/2}$-norm of curvature, and the auxiliary constant $C_1$. The strongest
results are in dimension 4, where $L^2$ curvature bounds are equivalent to
upper bounds on the Euler number. We obtain necessary and sufficient conditions
for limits to be compact.


title: Measurements of Top Quark Properties at the Tevatron

abstract:
  The precise measurement of the top quark properties is a stringent test of
the Standard Model of Particles and Fields. This reports presents the latest
results from the CDF and D0 collaborations with an integrated data sample of up
to 2.3/fb.


title:
Monte Carlo Simulation for the Formation and Growth of Low
  Dimensionality Phases During Underpotential Deposition of Ag on Au(100)

abstract:
  Simulation studies are undertaken for the system Ag/Au(100) by means of grand
canonical Monte Carlo applied to a large lattice system. The interactions are
calculated using the embedded atom model. The formation of adsorbed Ag phases
of low dimensionality on Ag(100) is investigated and the influence of surface
defects on the shape of the adsorption isotherms is studied. The results of the
simulations are discussed in the light of experimental information available
from electrochemical measurements.


title:
Monte-Carlo and Bayesian techniques in gravitational wave burst data
  analysis

abstract:
  Monte-Carlo simulations are used in the gravitational wave burst detection
community to demonstrate and compare the properties of different search
techniques. We note that every Monte-Carlo simulation has a corresponding
optimal search technique according to both the non-Bayesian Neyman-Pearson
criterion and the Bayesian approach, and that this optimal search technique is
the Bayesian statistic. When practical, we recommend deriving the optimal
statistic for a credible Monte-Carlo simulation, rather than testing ad hoc
statistics against that simulation.


title:
Gaussian Schell Source as Model for Slit-Collimated Atomic and Molecular
  Beams

abstract:
  We derive the spatial coherence and intensity profiles of beams emerging from
two consecutive collimating apertures, and compare our results with data. We
show how to make a Gaussian Schell-model (GSM) beam by assuming Gaussian
apertures. Then we compare the intensity profile, the transverse coherence
width and the divergence angle of a GSM beam with those same properties of a
beam that is collimated with two hard-edged slits. The GSM beam formulae are
simpler, and offer an intuitive way to understand how partially coherent beams
interact with interferometers.


title: Remarks on generators and dimensions of triangulated categories

abstract:
  In this paper we prove that the dimension of the bounded derived category of
coherent sheaves on a smooth quasi-projective curve is equal to one. We also
discuss dimension spectrums of these categories.


title: Explicit reduction modulo $p$ of certain crystalline representations

abstract:
  We use the p-adic local Langlands correspondence for GL_2(Q_p) to explicitly
compute the reduction modulo p of crystalline representations of small slope,
and give applications to modular forms.


title: How rare are diffusive rare events?

abstract:
  We study the time until first occurrence, the first-passage time, of rare
density fluctuations in diffusive systems. We approach the problem using a
model consisting of many independent random walkers on a lattice. The existence
of spatial correlations makes this problem analytically intractable. However,
for a mean-field approximation in which the walkers can jump anywhere in the
system, we obtain a simple asymptotic form for the mean first-passage time to
have a given number k of particles at a distinguished site. We show
numerically, and argue heuristically, that for large enough k, the mean-field
results give a good approximation for first-passage times for systems with
nearest-neighbour dynamics, especially for two and higher spatial dimensions.
Finally, we show how the results change when density fluctuations anywhere in
the system, rather than at a specific distinguished site, are considered.


title: Optimal control of electromagnetic field using metallic nanoclusters

abstract:
  The dielectric properties of metallic nanoclusters in the presence of an
applied electromagnetic field are investigated using non-local linear response
theory. In the quantum limit we find a non-trivial dependence of the induced
field and charge distribution on the spatial separation between the clusters
and on the frequency of the driving field. Using a genetic algorithm, these
quantum functionalities are exploited to custom-design sub-wavelength lenses
with a frequency controlled switching capability.


title:
Frequent Occurrence of High-speed Local Mass Downflows on the Solar
  Surface

abstract:
  We report on new spectro-polarimetric measurements with simultaneous filter
imaging observation, revealing the frequent appearance of polarization signals
indicating high-speed, probably supersonic, downflows that are associated with
at least three different configurations of magnetic fields in the solar
photosphere. The observations were carried out with the Solar Optical Telescope
onboard the {\em Hinode} satellite. High speed downflows are excited when a
moving magnetic feature is newly formed near the penumbral boundary of
sunspots. Also, a new type of downflows is identified at the edge of sunspot
umbra that lack accompanying penumbral structures. These may be triggered by
the interaction of magnetic fields sweeped by convection with well-concentrated
magnetic flux. Another class of high speed downflows are observed in quiet sun
and sunspot moat regions. These are closely related to the formation of small
concentrated magnetic flux patches. High speed downflows of all types are
transient time-dependent mass motions. These findings suggest that the
excitation of supersonic mass flows are one of the key observational features
of the dynamical evolution occurring in magnetic-field fine structures on the
solar surface.


title: Electron Beam Instability in Left-Handed Media

abstract:
  We predict that two electron beams can develop an instability when passing
through a slab of left-handed media (LHM). This instability, which is inherent
only for LHM, originates from the backward Cherenkov radiation and results in a
self-modulation of the beams and radiation of electromagnetic waves. These
waves leave the sample via the rear surface of the slab (the beam injection
plane) and form two shifted bright circles centered at the beams. A simulated
spectrum of radiation has well-separated lines on top of a broad continuous
spectrum, which indicates dynamical chaos in the system. The radiation
intensity and its spectrum can be controlled either by the beams' current or by
the distance between the two beams.


title:
Virtual Compton Scattering measurements in the $\gamma^* N\to \Delta$
  transition

abstract:
  We report on new H$(e,e^\prime p)\gamma$ measurements in the $\Delta(1232)$
resonance at $Q^2=0.06$ (GeV/c) carried out simultaneously with H$(e,e^\prime
p)\pi^0$. It is the lowest $Q^2$ for which the virtual Compton scattering (VCS)
reaction has been studied in the first resonance region. The VCS measured cross
sections are well described by dispersion-relation calculations in which the
multipole amplitudes derived from H$(e,e^\prime p)\pi^0$ data are used as
input, thus confirming the compatibility of the results. The derived resonant
magnetic dipole amplitude $M^{3/2}_{1+} = (40.60 \pm
0.70_{stat+sys})(10^{-3}/m_{\pi^+})$ at $W=$ 1232 MeV is in excellent agreement
with the value extracted from H$(e,e^\prime p)\pi^0$ measurements.


title:
Approximating L1-distances between mixture distributions using random
  projections

abstract:
  We consider the problem of computing L1-distances between every pair
ofcprobability densities from a given family. We point out that the technique
of Cauchy random projections (Indyk'06) in this context turns into stochastic
integrals with respect to Cauchy motion.
  For piecewise-linear densities these integrals can be sampled from if one can
sample from the stochastic integral of the function x->(1,x). We give an
explicit density function for this stochastic integral and present an efficient
sampling algorithm. As a consequence we obtain an efficient algorithm to
approximate the L1-distances with a small relative error.
  For piecewise-polynomial densities we show how to approximately sample from
the distributions resulting from the stochastic integrals. This also results in
an efficient algorithm to approximate the L1-distances, although our inability
to get exact samples worsens the dependence on the parameters.


title:
The Spin-1 Heisenberg Antiferromagnet: New Results from Series
  Expansions

abstract:
  We calculate ground state properties (energy, magnetization, susceptibility)
and one-particle spectra for the $S = 1$ Heisenberg antiferromagnet with
easy-axis or easy-plane single site anisotropy, on the square lattice. Series
expansions are used, in each of three phases of the system, to obtain
systematic and accurate results. The location of the quantum phase transition
in the easy-plane sector is determined. The results are compared with spin-wave
theory.


title:
Transceiver Design with Low-Precision Analog-to-Digital Conversion : An
  Information-Theoretic Perspective

abstract:
  Modern communication receiver architectures center around digital signal
processing (DSP), with the bulk of the receiver processing being performed on
digital signals obtained after analog-to-digital conversion (ADC). In this
paper, we explore Shannon-theoretic performance limits when ADC precision is
drastically reduced, from typical values of 8-12 bits used in current
communication transceivers, to 1-3 bits. The goal is to obtain insight on
whether DSP-centric transceiver architectures are feasible as communication
bandwidths scale up, recognizing that high-precision ADC at high sampling rates
is either unavailable, or too costly or power-hungry. Specifically, we evaluate
the communication limits imposed by low-precision ADC for the ideal real
discrete-time Additive White Gaussian Noise (AWGN) channel, under an average
power constraint on the input. For an ADC with K quantization bins (i.e., a
precision of log2 K bits), we show that the Shannon capacity is achievable by a
discrete input distribution with at most K + 1 mass points. For 2-bin (1-bit)
symmetric ADC, this result is tightened to show that binary antipodal signaling
is optimum for any signal-to-noise ratio (SNR). For multi-bit ADC, the capacity
is computed numerically, and the results obtained are used to make the
following encouraging observations regarding system design with low-precision
ADC : (a) even at moderately high SNR of up to 20 dB, 2-3 bit quantization
results in only 10-20% reduction of spectral efficiency, which is acceptable
for large communication bandwidths, (b) standard equiprobable pulse amplitude
modulation with ADC thresholds set to implement maximum likelihood hard
decisions is asymptotically optimum at high SNR, and works well at low to
moderate SNRs as well.


title: A Lower Bound on the Area of a 3-Coloured Disk Packing

abstract:
  Given a set of unit-disks in the plane with union area $A$, what fraction of
$A$ can be covered by selecting a pairwise disjoint subset of the disks? Rado
conjectured 1/4 and proved $1/4.41$. Motivated by the problem of
channel-assignment for wireless access points, in which use of 3 channels is a
standard practice, we consider a variant where the selected subset of disks
must be 3-colourable with disks of the same colour pairwise-disjoint. For this
variant of the problem, we conjecture that it is always possible to cover at
least $1/1.41$ of the union area and prove $1/2.09$. We also provide an
$O(n^2)$ algorithm to select a subset achieving a $1/2.77$ bound.


title: Quasilocal mass in general relativity

abstract:
  There have been many attempts to define the notion of quasilocal mass for a
spacelike 2-surface in spacetime by the Hamilton-Jacobi analysis. The essential
difficulty in this approach is to identify the right choice of the background
configuration to be subtracted from the physical Hamiltonian. Quasilocal mass
should be nonnegative for surfaces in general spacetime and zero for surfaces
in flat spacetime. In this letter, we propose a new definition of
gauge-independent quasilocal mass and prove that it has the desired properties.


title:
2DPHOT: A Multi-purpose Environment for the Two-dimensional Analysis of
  Wide-field Images

abstract:
  We describe 2DPHOT, a general purpose analysis environment for source
detection and analysis in deep wide-field images. 2DPHOT is an automated tool
to obtain both integrated and surface photometry of galaxies in an image, to
perform reliable star-galaxy separation with accurate estimates of
contamination at faint flux levels, and to estimate completeness of the image
catalog. We describe the analysis strategy on which 2DPHOT is based, and
provide a detailed description of the different algorithms implemented in the
package. This new environment is intended as a dedicated tool to process the
wealth of data from wide-field imaging surveys. To this end, the package is
complemented by 2DGUI, an environment that allows multiple processing of data
using a range of computing architectures.


title: Decaying D-branes and Moving Mirrors

abstract:
  We present an exact time-dependent solution to the effective D-brane
world-volume theory which describes an inhomogeneous decay of a brane-antibrane
system. We compute the quantum energy flux induced by the particle creation in
this inhomogeneous and time-dependent background. We find that this calculation
is essentially equivalent to that of the moving mirror system. In the initial
stage, the energy flux turns out to be thermal with the temperature given by
the inverse of the distance between the brane and the antibrane. Later it
changes its sign and becomes a negative energy flux. Our result may be relevant
for the (p)reheating process or/and the evolution of cosmic string network
after stringy brane inflation.


title:
Microlocalization and nonexistence of $C^2$ Levi-flat hypersurfaces in
  $\Bbb CP^2

abstract:
  To be prudent, the paper has been withdrawn by the authors, due an error
(missing complex conjugate sign) in Equation (2.5). We are very grateful to
Marco Brunella for pointed out the error.


title: Sequential star formation in a cometary globule (BRC37) of IC1396

abstract:
  We have carried out near-IR/optical observations to examine star formation
toward a bright-rimmed cometary globule (BRC37) facing the exciting star(s) of
an HII region (IC1396) containing an IRAS source, which is considered to be an
intermediate-mass protostar. With slit-less spectroscopy we detected ten
H_alpha emission stars around the globule, six of which are near the tip of the
globule and are aligned along the direction to the exciting stars. There is
evidence that this alignment was originally towards an O9.5 star, but has
evolved to align towards a younger O6 star when that formed. Near-IR and
optical photometry suggests that four of these six stars are low-mass young
stellar objects (YSOs) with masses of ~0.4 M_sun. Their estimated ages of ~1
Myr indicate that they were formed at the tip in advance of the formation of
the IRAS source. Therefore, it is likely that sequential star formation has
been taking place along the direction from the exciting stars towards the IRAS
source, due to the UV impact of the exciting star(s). Interestingly, one faint,
H_alpha emission star, which is the closest to the exciting star(s), seems to
be a young brown dwarf that was formed by the UV impact in advance of the
formation of other YSOs at the tip.


title: A Dynamical Boolean Network

abstract:
  We propose a Dynamical Boolean Network (DBN), which is a Virtual Boolean
Network (VBN) whose set of states is fixed but whose transition matrix can
change from one discrete time step to another. The transition matrix $T_{k}$ of
our DBN for time step $k$ is of the form $Q^{-1}TQ$, where $T$ is a transition
matrix (of a VBN) defined at time step $k$ in the course of the construction of
our DBN and $Q$ is the matrix representation of some randomly chosen
permutation $P$ of the states of our DBN. For each of several classes of such
permutations, we carried out a number of simulations of a DBN with two nodes;
each of our simulations consisted of 1,000 trials of 10,000 time steps each. In
one of our simulations, only six of the 16 possible single-node transition
rules for a VBN with two nodes were visited a total of 300,000 times (over all
1,000 trials). In that simulation, linearity appears to play a significant role
in that three of those six single-node transition rules are transition rules of
a Linear Virtual Boolean Network (LVBN); the other three are the negations of
the first three. We also discuss the notions of a Probabilistic Boolean Network
and a Hidden Markov Model--in both cases, in the context of using an arbitrary
(though not necessarily one-to-one) function to label the states of a VBN.


title:
The debeamed luminosity, sychrotron peak frequency and black hole mass
  of BL Lac objects

abstract:
  We estimate the intrinsic luminosities and synchrotron peak frequency using
the derived Doppler factor for a sample of 170 BL Lac objects, of which the
synchrotron peak frequency are derived by fitting the SED constructed with the
collected multi-band data from literatures. We find that the debeamed radio and
optical core luminosities follow the same correlation found for FR I radio
galaxies, which is in support of the unification of the BL Lac objects and the
FR I galaxies based on orientation. For the debeamed luminosity at synchrotron
peak frequency, we find a significant positive correlation between the
luminosity and intrinsic synchrotron peak frequency. This implies that the more
powerful sources may have the majority of jet emission at higher frequency. At
synchrotron peak frequency, the intrinsic luminosity and black hole mass show
strong positive correlation, while mild correlation is found in the case of jet
power, indicating that the more powerful sources may have heavier black hole.


title:
A short, based on the mixed volume, proof of Liggett's theorem on the
  convolution of ultra-logconcave sequences

abstract:
  R. Pemantle conjectured, and T.M. Liggett proved in 1997, that the
convolution of two ultra-logconcave is ultra-logconcave. Liggett's proof is
elementary but long. We present here a short proof, based on the mixed volume
of convex sets.


title: The amplitude of solar oscillations using stellar techniques

abstract:
  The amplitudes of solar-like oscillations depend on the excitation and
damping, both of which are controlled by convection. Comparing observations
with theory should therefore improve our understanding of the underlying
physics. However, theoretical models invariably compute oscillation amplitudes
relative to the Sun, and it is therefore vital to have a good calibration of
the solar amplitude using stellar techniques. We have used daytime spectra of
the Sun, obtained with HARPS and UCLES, to measure the solar oscillations and
made a detailed comparison with observations using the BiSON helioseismology
instrument. We find that the mean solar amplitude measured using stellar
techniques, averaged over one full solar cycle, is 18.7 +/- 0.7 cm/s for the
strongest radial modes (l=0) and 25.2 +/- 0.9 cm/s for l=1. In addition, we use
simulations to establish an equation that estimates the uncertainty of
amplitude measurements that are made of other stars, given that the mode
lifetime is known. Finally, we also give amplitudes of solar-like oscillations
for three stars that we measured from a series of short observations with HARPS
(gamma Ser, beta Aql and alpha For), together with revised amplitudes for five
other stars for which we have previously published results (alpha Cen A, alpha
Cen B, beta Hyi, nu Ind and delta Pav).


title: Hash Property and Fixed-rate Universal Coding Theorems

abstract:
  The aim of this paper is to prove the achievability of fixed-rate universal
coding problems by using our previously introduced notion of hash property.
These problems are the fixed-rate lossless universal source coding problem and
the fixed-rate universal channel coding problem. Since an ensemble of sparse
matrices satisfies the hash property requirement, it is proved that we can
construct universal codes by using sparse matrices.