title:
Information Geometry of q-Gaussian Densities and Behaviors of Solutions
  to Related Diffusion Equations

abstract:
  This paper presents new geometric aspects of the behaviors of solutions to
the porous medium equation (PME) and its associated equation. First we discuss
the Legendre structure with information geometry on the manifold of generalized
exponential densities. Next by considering such a structure in particular on
the q-Gaussian densities, we derive several physically and geometrically
interesting properties of the solutions. They include, for example,
characterization of the moment-conserving projection of a solution, evaluation
of evolutional velocities of the second moments and the convergence rate to the
manifold in terms of the geodesic curves, divergence and so on.

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


title:
Modeling Merging Galaxies using MINGA - Improving Restricted N-body by
  Dynamical Friction

abstract:
  Modeling interacting galaxies to reproduce observed systems is still a
challenge due to the extended parameter space (among other problems). Orbit and
basic galaxy parameters can be tackled by fast simulation techniques like the
restricted N-body method, applied in the fundamental work by Toomre & Toomre
(1972). This approach allows today for the study of millions of models in a
short time. One difficulty for the classical restricted N-body method is the
missing orbital decay, not allowing for galaxy mergers. Here we present an
extension of the restricted N-body method including dynamical friction. This
treatment has been developed by a quantitative comparison with a set of
self-consistent merger simulations. By varying the dynamical friction
(formalism, strength and direction), we selected the best-fitting parameters
for a set of more than 250000 simulations. We show that our treatment reliably
reproduces the orbital decay and tidal features of merging disk galaxies for
mass ratios up to q=1/3 between host and satellite. We implemented this
technique into our genetic algorithm based modeling code MINGA and present
first results.


title:
Dynamics of the Density Matrix in Contact with a Thermal Bath and the
  Quantum Master Equation

abstract:
  We study the structure of the time evolution of the density matrix in contact
with a thermal bath in a standard projection operator sheme. The reduced
density matrix of the system in the steady state is obtained by tracing out the
degree of freedom of the thermal bath from the equilibrium density matrix of
the total system. This reduced density matrix is modified by the interaction,
and is different from that of the equilibrium of the system alone. We
explicitly calculate the contribution of each term in quantum master equation
to the realization of the steady state density matrix, and make clear roles of
each term. By making use of the role of each term, the properties of the
commonly used quantum master equation are examined.


title:
Flux-Vector-Splitting (FVS) method for Z4 formalism and its numerical
  analysis

abstract:
  The previously developed Flux-Vector-Splitting (FVS) method was formulated
here for the first-order version of Z4 formalism. Then, the characteristics of
this method formulated for Z4 formalism were studied by numerically analyzing
the evolution of two types of black holes (free and stuffed). Finally, these
numerical results from the FVS method were compared with those from the Local
Lax Friedrichs and Modified Local Lax Friedrichs methods to reveal the
dependency of numerical solution by Z4 formalism on the choice of numerical
scheme.


title: Sites for Gamma-ray Astronomy in Argentina

abstract:
  We have searched for possible sites in Argentina for the installation of
large air Cherenkov telescope arrays and water Cherenkov systems. At present
seven candidates are identified at altitudes from 2500 to 4500 m. The highest
sites are located at the Northwest of the country, in La Puna. Sites at 2500
and 3100 m are located in the West at El Leoncito Observatory, with excellent
infrastructure. A description of these candidate sites is presented with
emphasis on infrastructure and climatology.


title: Energy loss of charged particles moving parallel to a magnesium surface

abstract:
  We present it ab initio calculations of the electronic energy loss of charged
particles moving outside a magnesium surface, from a realistic description of
the one-electron band structure and a full treatment of the dynamical
electronic response of valence electrons. Our results indicate that the finite
width of the plasmon resonance, which is mainly due to the presence of
band-structure effects, strongly modifies the asymptotic behaviour of the
energy loss at large distances from the surface. This effect is relevant for
the understanding of the interaction between charged particles and the internal
surface of microcapillaries.


title: A solid state light-matter interface at the single photon level

abstract:
  Coherent and reversible mapping of quantum information between light and
matter is an important experimental challenge in quantum information science.
In particular, it is a decisive milestone for the implementation of quantum
networks and quantum repeaters. So far, quantum interfaces between light and
atoms have been demonstrated with atomic gases, and with single trapped atoms
in cavities. Here we demonstrate the coherent and reversible mapping of a light
field with less than one photon per pulse onto an ensemble of 10 millions atoms
naturally trapped in a solid. This is achieved by coherently absorbing the
light field in a suitably prepared solid state atomic medium. The state of the
light is mapped onto collective atomic excitations on an optical transition and
stored for a pre-programmed time up of to 1 mu s before being released in a
well defined spatio-temporal mode as a result of a collective interference. The
coherence of the process is verified by performing an interference experiment
with two stored weak pulses with a variable phase relation. Visibilities of
more than 95% are obtained, which demonstrates the high coherence of the
mapping process at the single photon level. In addition, we show experimentally
that our interface allows one to store and retrieve light fields in multiple
temporal modes. Our results represent the first observation of collective
enhancement at the single photon level in a solid and open the way to multimode
solid state quantum memories as a promising alternative to atomic gases.


title:
Numerical Analysis of Relativistic Boltzmann-kinetic Equations to Solve
  Relativistic Shock Layer Problems

abstract:
  The relativistic shock layer problem was numerically analyzed by using two
relativistic Boltzmann-kinetic equations. One is Marle model, and the other is
Anderson-Witting model. As with Marle model, the temperature of the gain term
was determined from its relation with the dynamic pressure in the framework of
14-moments theory. From numerical results of the relativistic shock layer
problem, behaviors of projected moments in the nonequilibrium region were
clarified. Profiles of the heat flux given by Marle model and Anderson-Witting
model were quite adverse to the profile of the heat flux approximated by
Navier-Stokes-Fourier law. On the other hand, profiles of the heat flux given
by Marle model and Anderson-Witting model were similar to the profile
approximated by Navier-Stokes-Fourier law. Additionally we discuss the
differences between Anderson-Witting model and Marle model by focusing on the
fact that the relaxational rate of the distribution function depends on both
flow velocity and molecular velocity for Anderson-Witting model, while it
depends only on the molecular velocity for Marle model.


title:
Boundary-induced violation of the Dirac fermion parity and its
  signatures in local and global tunneling spectra of graphene

abstract:
  Extended defects in graphene, such as linear edges, break the translational
invariance and can also have an impact on the symmetries specific to massless
Dirac-like quasiparticles in this material. The paper examines the consequences
of a broken Dirac fermion parity in the framework of the effective boundary
conditions varying from the Berry-Mondragon mass confinement to a zigzag edge.
The parity breaking reflects the structural sublattice asymmetry of zigzag-type
edges and is closely related to the previously predicted time-reversal
symmetric edge states. We calculate the local and global densities of the edge
states and show that they carry a specific polarization, resembling, to some
extent, that of spin-polarized materials. The lack of the parity leads to a
nonanalytical particle-hole asymmetry in the edge-state properties. We use our
findings to interpret recently observed tunneling spectra in zigzag-terminated
graphene. We also propose a graphene-based tunneling device where the
particle-hole asymmetric edge states result in a strongly nonlinear
conductance-voltage characteristics, which could be used to manipulate the
tunneling transport.


title: Rough Sets Determined by Quasiorders

abstract:
  In this paper, the ordered set of rough sets determined by a quasiorder
relation $R$ is investigated. We prove that this ordered set is a complete,
completely distributive lattice. We show that on this lattice can be defined
three different kinds of complementation operations, and we describe its
completely join-irreducible elements. We also characterize the case in which
this lattice is a Stone lattice. Our results generalize some results of J.
Pomykala and J. A. Pomykala (1988) and M. Gehrke and E. Walker (1992) in case
$R$ is an equivalence.


title:
All "static" spherically symmetric perfect fluid solutions of Einstein's
  equations with constant equation of state parameter and finite-polynomial
  "mass function"

abstract:
  We look for "static" spherically symmetric solutions of Einstein's Equations
for perfect fluid source with equation of state $p=w\rho$. In order to include
the possibilities of recently popularized dark energy and phantom energy
possibly pervading the spacetime, we put no constraints on the constant $w$. We
consider all four cases compatible with the standard ansatz for the line
element, discussed in previous work. For each case we derive the equation
obeyed by the mass function or its analogs. For these equations, we find {\em
all} finite-polynomial solutions, including possible negative powers.
  For the standard case, we find no significantly new solutions, but show that
one solution is a static phantom solution, another a black hole-like solution.
For the dynamic and/or tachyonic cases we find, among others, dynamic and
static tachyonic solutions, a Kantowski-Sachs (KS) class phantom solution,
another KS-class solution for dark energy, and a second black hole-like
solution.
  The black hole-like solutions feature segregated normal and tachyonic matter,
consistent with the assertion of previous work. In the first black hole-like
solution, tachyonic matter is inside the horizon, in the second, outside.
  The static phantom solution, a limit of an old one, is surprising at first,
since phantom energy is usually associated with super-exponential expansion.
The KS-phantom solution stands out since its "mass function" is a ninth order
polynomial.


title: SN 2006gy: was it really extra-ordinary?

abstract:
  We present an optical photometric and spectroscopic study of the very
luminous type IIn SN 2006gy for a time period spanning more than one year. In
photometry, a broad, bright (M_R~-21.7) peak characterizes all BVRI light
curves. Afterwards, a rapid luminosity fading is followed by a phase of slow
luminosity decline between day ~170 and ~237. At late phases (>237 days),
because of the large luminosity drop (>3 mag), only upper visibility limits are
obtained in the B, R and I bands. In the near-infrared, two K-band detections
on days 411 and 510 open new issues about dust formation or IR echoes
scenarios. At all epochs the spectra are characterized by the absence of broad
P-Cygni profiles and a multicomponent Halpha profile, which are the typical
signatures of type IIn SNe. After maximum, spectroscopic and photometric
similarities are found between SN 2006gy and bright, interaction-dominated SNe
(e.g. SN 1997cy, SN 1999E and SN 2002ic). This suggests that ejecta-CSM
interaction plays a key role in SN 2006gy about 6 to 8 months after maximum,
sustaining the late-time-light curve. Alternatively, the late luminosity may be
related to the radioactive decay of ~3M_sun of 56Ni. Models of the light curve
in the first 170 days suggest that the progenitor was a compact star (R~6-8
10^(12)cm, M_ej~5-14M_sun), and that the SN ejecta collided with massive
(6-10M_sun), opaque clumps of previously ejected material. These clumps do not
completely obscure the SN photosphere, so that at its peak the luminosity is
due both to the decay of 56Ni and to interaction with CSM. A supermassive star
is not required to explain the observational data, nor is an extra-ordinarily
large explosion energy.


title: Quantum Hall quasielectrons - Abelian and non-Abelian

abstract:
  The quasiparticles in Quantum Hall liquids carry fractional charge and obey
fractional quantum statistics. Of particular recent interest are those with
non-Abelian statistics, since their braiding properties could in principle be
used for robust coding of quantum information. There is already a good
theoretical understanding of quasiholes both in Abelian and non-Abelian QH
states. Here we develop conformal field theory methods that allow for an
equally precise description of quasielectrons, and explicitly construct two-
and four-quasielectron excitations of the non-Abelian Moore-Read state.


title: Neutrinoless double beta decay search with the NEMO 3 experiment

abstract:
  The NEMO 3 experiment searches for neutrinoless double beta decay and makes
precision measurements of two-neutrino double beta decay in seven isotopes. The
latest two-neutrino half-life results are presented, together with the limits
on neutrinoless half-lives and the corresponding effective Majorana neutrino
masses. Also given are the limits obtained on neutrinoless double beta decay
mediated by Rp-violating SUSY, right-hand currents and different Majoron
emission modes.


title: Geometric structure in the principal series of the p-adic group G_2

abstract:
  In the representation theory of reductive $p$-adic groups $G$, the issue of
reducibility of induced representations is an issue of great intricacy. It is
our contention, expressed as a conjecture in [3], that there exists a simple
geometric structure underlying this intricate theory. We will illustrate here
the conjecture with some detailed computations in the principal series of
$G_2$.
  A feature of this article is the role played by cocharacters $h_c$ attached
to two-sided cells $c$ in certain extended affine Weyl groups.
  The quotient varieties which occur in the Bernstein programme are replaced by
extended quotients. We form the disjoint union $A(G)$ of all these extended
quotient varieties. We conjecture that, after a simple algebraic deformation,
the space $A(G)$ is a model of the smooth dual $Irr(G)$. In this respect, our
programme is a conjectural refinement of the Bernstein programme.
  The algebraic deformation is controlled by cocharacters $h_c$, one for each
two-sided cell $c$ in certain extended affine Weyl groups. The cocharacters
themselves appear to be closely related to Langlands parameters.


title: Analysis of tau -> Ks pion nu_tau Belle data in a chiral framework

abstract:
  The recent measurement of the tau -> Ks pion nu_tau spectrum by the Belle
Collaboration provides the frame to set forth a theoretical description of the
decay, which is based on the contributing vector F_+(s) and scalar F_0(s) form
factors. We show that a good representation of data is obtained through the use
of form factors calculated within resonance chiral theory and constrained by
dispersion relations and short-distance QCD. Hence we obtain a determination of
K*(892) parameters and the low-energy parameterization of F_+(s).


title: Adiabatic entanglement in two-atom cavity QED

abstract:
  We analyse the problem of a single mode field interacting with a pair of two
level atoms. The atoms enter and exit the cavity at different times. Instead of
using constant coupling, we use time dependent couplings which represent the
spatial dependence of the mode. Although the system evolution is adiabatic for
most of the time, a previously unstudied energy crossing plays a key role in
the system dynamics when the atoms have a time delay. We show that conditional
atom-cavity entanglement can be generated, while for large photon numbers the
entangled system has a behaviour which can be mapped onto the single atom
Jaynes-Cummings model. Exploring the main features of this system we propose
simple and fairly robust methods for entangling atoms independently of the
cavity, for quantum state mapping, and for implementing SWAP and C-NOT gates
with atomic qubits.


title: Fermiology via the electron momentum distribution

abstract:
  Investigations of the Fermi surface via the electron momentum distribution
reconstructed from either angular correlation of annihilation radiation (or
Compton scattering) experimental spectra are presented. The basis of these
experiments and mathematical methods applied in reconstructing
three-dimensional densities from line (or plane) projections measured in these
experiments are described. The review of papers where such techniques have been
applied to study the Fermi surface of metallic materials with showing their
main results is also done.


title:
Quantum interference effects in electron transport through nitrobenzene
  with pyridil anchor groups

abstract:
  We present density functional theory (DFT) based non-equilibrium Green's
function (NEGF) calculations for the conductance through a nitrobenzene
molecule, which is anchored by pyridil-groups to Au electrodes. This work is
building up on earlier theoretical studies where quantum interference effects
(QIE) have been identified both in qualitative tight binding and in DFT
descriptions for the same molecule with different chemical connections to the
leads. The novelty in the current contribution is two-fold: i) The
pyridil-anchors guarantee for the conductance to be determined by rather narrow
peaks situated closely to the Fermi energy which is relevant because it might
maximize the impact of quantum interferences on the I/V behaviour. In a scan of
eight different junction setups, where the connection sites of aromatic rings,
their torsion angle with respect to each other and the surface structure have
been varied, QIE was found to dominate the conductance for only one planar
geometry. For finite torsion angles between aromatic rings the effect moves to
higher energies and would therefore only be accessible for experimental
observation in a gated junction. ii) A detailed comparison between simple
topological models and DFT results for the investigated systems aims at
assessing the usefulness of such models as analysis tools for a better
understanding of the physics of QIE and its structure dependence.


title: Bose-Hubbard phase diagram with arbitrary integer filling

abstract:
  We study the transition from a Mott insulator to a superfluid in both the
two- and the three-dimensional Bose-Hubbard model at zero temperature,
employing the method of the effective potential. Converting Kato's perturbation
series into an algorithm capable of reaching high orders, we obtain accurate
critical parameters for any integer filling factor. Our technique allows us to
monitor both the approach to the mean-field limit by considering spatial
dimensionalities $d > 3$, and to the quantum rotor limit of high filling, which
refers to an array of Josephson junctions.


title: Noncommutative hyperbolic geometry on the unit ball of $B(H)^n$

abstract:
  In this paper we introduce a hyperbolic distance $\delta$ on the
noncommutative open ball $[B(H)^n]_1$, where $B(H)$ is the algebra of all
bounded linear operators on a Hilbert space $H$, which is a noncommutative
extension of the Poincare-Bergman metric on the open unit ball of $C^n$. We
prove that $\delta$ is invariant under the action of the group
$Aut([B(H)^n]_1)$ of all free holomorphic automorphisms of $[B(\cH)^n]_1$, and
show that the $\delta$-topology and the usual operator norm topology coincide
on $[B(H)^n]_1$. Moreover, we prove that $[B(H)^n]_1$ is a complete metric
space with respect to the hyperbolic metric and obtained an explicit formula
for $\delta$ in terms of the reconstruction operator. A Schwarz-Pick lemma for
bounded free holomorphic functions on $[B(H)^n]_1$, with respect to the
hyperbolic metric, is also obtained.


title:
Non-minimally coupled canonical, phantom and quintom models of
  holographic dark energy

abstract:
  We investigate canonical, phantom and quintom models, with the various fields
being non-minimally coupled to gravity, in the framework of holographic dark
energy. We classify them and we discuss their cosmological implications. In
particular, we examine the present value of the dark energy equation-of-state
parameter and the crossing through the phantom divide, and we extract the
conditions for a future cosmological singularity. The combined scenarios are in
agreement with observations and reveal interesting cosmological behaviors.


title:
INTEGRAL Cross-calibration Status: Crab observations between 3 keV and 1
  MeV

abstract:
  We present results of Crab observations by the INTEGRAL instruments. A
simultaneous fit allows us to demonstrate that INTEGRAL provides reliable
spectra over its wide energy range.


title: Elliptic Equations Involving Meausres

abstract:
  We present the moste recent results dealing with the theory of semilinear
elliptic equations with measures data


title:
Anomalies in Universal Intensity Scaling in Ultrarelativistic
  Laser-Plasma Interactions

abstract:
  Laser light incident on targets at intensities such that the electron
dynamics is ultrarelativistic gives rise to a harmonic power spectrum extending
to high orders and characterized by a relatively slow decay with the harmonic
number m that follows a power law dependence, m^{-p}. Relativistic similarity
theory predicts a universal value for p = 8/3 up to some cut-off m = m*. The
results presented in this work suggest that under conditions in which plasma
effects contribute to the emission spectrum, the extent of this contribution
may invalidate the concept of universal decay. We report a decay with harmonic
number in the ultrarelativistic range characterised by an index 5/3 < p < 7/3,
significantly weaker than that predicted by the similarity model.


title: Reminiscences about numerical schemes

abstract:
  This preprint appeared firstly in Russian in 1997. Some truncated versions of
this preprint were published in English and French, here a fully translated
version is presented. The translation in English was done by O. V. Feodoritova
and V. Deledicque to whom I express my gratitude.
  In the present paper I will describe how the first variant of the Godunov's
scheme has been elaborated in 1953-1954 and tell about all modifications
realized by myself (until 1969) and the group of scientists from the Institute
of Applied Mathematics in Moscow (which has become the M.V.Keldysh Institute of
Applied Mathematics).


title: From persistent random walks to the telegraph noise

abstract:
  We study a family of memory-based persistent random walks and we prove weak
convergences after space-time rescaling. The limit processes are not only
Brownian motions with drift. We have obtained a continuous but non-Markov
process $(Z_t)$ which can be easely expressed in terms of a counting process
$(N_t)$. In a particular case the counting process is a Poisson process, and
$(Z_t)$ permits to represent the solution of the telegraph equation. We study
in detail the Markov process $((Z_t,N_t); t\ge 0)$.


title: Reducibility of quasiperiodic cocycles in linear Lie groups

abstract:
  Let G be a linear Lie group. We define the G-reducibility of a continuous or
discrete cocycle modulo N. We show that a G-valued continuous or discrete
cocycle which is GL(n,C)-reducible is in fact G-reducible modulo 2 if
G=GL(n,R),SL(n,R),Sp(n,R) or O(n) and modulo 1 if G=U(n).


title: Evolution and chemical and dynamical effects of high-mass stars

abstract:
  We review general characteristics of massive stars, present the main
observable constraints that stellar models should reproduce. We discuss the
impact of massive star nucleosynthesis on the early phases of the chemical
evolution of the Milky Way (MW). We show that rotating models can account for
the important primary nitrogen production needed at low metallicity.
Interestingly such rotating models can also better account for other features
as the variation with the metallicity of the C/O ratio. Damped Lyman Alpha
(DLA) systems present similar characteristics as the halo of the MW for what
concern the N/O and C/O ratios. Although in DLAs, the star formation history
might be quite different from that of the halo, in these systems also, rotating
stars (both massive and intermediate) probably play an important role for
explaining these features. The production of primary nitrogen is accompanied by
an overproduction of other elements as $^{13}$C, $^{22}$Ne and s-process
elements. We show also how the observed variation with the metallicity of the
number ratio of type Ibc to type II supernovae may be a consequence of the
metallicity dependence of the line-driven stellar winds.


title: Disques J-holomorphes contenus dans une hypersurface

abstract:
  We study germs of J-Holomorphic curves contained in $M$, a real analytic
hypersurface of an symplectic manifold of dimension 4. We show, under
topological hypothesis on $M$, that if $M$ is compact then $M$ is of finite
type and so there is no germs of $J$-holomorphic curves on $M$(with $J$ adapted
with the symplectic form). In $\Bbb{C}^2$ with the standard complex structure,
this is a classical result of Diederich-Fornaess.


title:
The p-Laplace heat equation with a source term : self-similar solutions
  revisited

abstract:
  We study the self-similar solutions of any sign of the equation
u_{t}-div(|∇u|^{p-2}∇u)=|u|^{q-1}u, in R^{N}, where p,q>1. We
extend the results of Haraux-Weissler obtained for p=2 to the case q>p-1>0. In
particular we study the existence of slow or fast decaying solutions. For given
t>0, the fast solutions u(t,.) have a compact support in R^{N} when p>2, and
|x|^{p/(2-p)}u(t,x) is bounded at infinity when p<2. We describe the behaviour
for large |x| of all the solutions. According to the position of q with respect
to the first critical exponent p-1+p/N and the critical Sobolev exponent
q^{∗}, we study the existence of positive solutions, or the number of the
zeros of u(t,.). We prove that any solution u(t,.) is oscillatory when p<2 and
q is closed to 1.


title:
High-statistics measurement of neutral-pion pair production in
  two-photon collisions

abstract:
  We have measured the cross section for pi^0 pi^0 production in two-photon
collisions using a data sample with an ntegrated luminosity of 95 fb^-1
collected with the Belle detector. We find at least four resonant structures
including a peak from f_0(980), and a fitting of the result to partial-wave
amplitudes assuming some resonances are applied. We also make a discussion on
the higher-energy region data based on the preliminary results from an
increased sample corresponding to the integrated luminosity of 223 fb^-1.


title: Hyperbolic geometry on the unit ball of $B(H)^n$ and dilation theory

abstract:
  In this paper we continue our investigation concerning the hyperbolic
geometry on the noncommutative ball $[B(H)^n]_1^-$, where $B(H)$ is the algebra
of all bounded linear operators on a Hilbert space $H$, and its implications to
noncommutative function theory. The central object is an intertwining operator
$L_{B,A}$ of the minimal isometric dilations of $A, B\in [B(H)^n]_1^-$, which
establishes a strong connection between noncommutative hyperbolic geometry on
$[B(H)^n]_1^-$ and multivariable dilation theory.
  The goal of this paper is to study the operator $L_{B,A}$ and its connections
to the hyperbolic metric $\delta$ on the Harnack parts of $[B(H)^n]_1^-$. We
study the geometric structure of the operator $L_{B,A}$ and obtain new
characterizations for the Harnack domination (resp. equivalence) in
$[B(H)^n]_1^-$. We express $\|L_{B,A}\|$ in terms of the reconstruction
operators $R_A$ and $R_B$, and obtain a Schwartz-Pick lemma for contractive
free holomorphic functions on $[B(H)^n]_1$ with respect to the intertwining
operator $L_{B,A}$. As a consequence, we deduce a Schwartz-Pick lemma for
operator-valued multipliers of the Drury-Arveson space, with respect to the
hyperbolic metric.


title: Modeling Massive Stars with Rotation: the Case of Nitrogen Enrichments

abstract:
  Recently, the concept of rotational mixing has been challenged by some
authors (e.g. Hunter et al. 2008). We show that the excess N/H is a
multivariate function f(M, age, v, sin i, multiplicity,Z). To find a
correlation of a multivariate function with some parameter, it is evidently
necessary to limit as much as possible the range of the other involved
parameters. When this is done, the concept of rotational mixing is supported by
the observations. We also show that the sample data are not free from several
biases. A fraction of about 20% of the stars may escape to the relation as a
result of binary evolution.


title: Quantum Isometry groups of the Podles Spheres

abstract:
  For $\mu \in (0,1), c> 0,$ we identify the quantum group $SO_\mu(3)$ as the
universal object in the category of compact quantum groups acting by
`orientation and volume preserving isometries' in the sense of \cite{goswami2}
on the natural spectral triple on the Podles sphere $S^2_{\mu, c}$ constructed
by Dabrowski, D'Andrea, Landi and Wagner in \cite{{Dabrowski_et_al}}.


title: Why the two-pulse photon echo is not a good quantum memory protocol

abstract:
  We consider in this paper a two-pulse photon echo sequence as a potential
quantum light storage protocol. It is widely believed that a two-pulse scheme
should lead to very low efficiency and is then not relevant for this specific
application. We show experimentally by using a Tm${}^{3+}$:YAG crystal that
such a protocol is on contrary very efficient and even too efficient to be
considered as a good quantum storage protocol. Our experimental work allows us
to point out on one side the real limitations of this scheme and on the other
side its benefits which can be a source of inspiration to conceive more
promising procedures with rare-earth ion doped crystals.


title:
Semileptonic decays of charmed and beauty baryons with sterile neutrinos
  in the final state

abstract:
  We obtain tree-level estimates of various differential branching ratios of
heavy baryon decays with massive sterile neutrinos $\nu_{x}$ in the final
state. Heavy sterile neutrinos can be searched for in heavy baryon decays with
missing mass as a signature as well as in fixed target experiments, where heavy
baryon decays contribute to sterile neutrino production, with sterile neutrino
decays as a signature. Generally, charmed baryons are found to be less
promising than charmed mesons, in contrast to b-hadrons. In the latter case,
branching ratios of beauty mesons and baryons into sterile neutrinos are of the
same order. As a consequence, at high energies beauty baryons give contribution
to sterile neutrino production comparable to the contribution of beauty mesons
(up to about 15%). Experimental limits on active-to-sterile mixing are quite
strong for neutrinos lighter than D-meson but for heavier neutrinos they are
weaker. As an example, for neutrino masses in the range 2 GeV $\lesssim
m_{\nu_{x}}\lesssim 2.5$ GeV, current data imply that the bounds on
$\Lambda_{b}$-hyperon branching ratios into sterile neutrinos are ${\rm
Br}(\Lambda_b\to\Lambda_c+e^-+\nu_x)\lesssim 1.3\cdot10^{-5}-1.7\cdot10^{-6}$
and ${\rm Br}(\Lambda_b\to\Lambda_c+\mu^-+\nu_x)\lesssim
3.9\cdot10^{-7}-1.4\cdot10^{-7}$.


title: Inclusive and exclusive $b\to s/d\gamma$

abstract:
  In this article, I review the recent results for inclusive and exclusive
measurements for $b\to s\gamma$ and $b\to d\gamma$ decays from $B$ factories
Belle and Babar. I describe the measurement of branching fraction and direct CP
violating asymmetry for inclusive $B\to X_s\gamma$ decay. For results of $b\to
d\gamma$ process, I introduce the measurement of branching fraction of
exclusive $b\to d\gamma$ modes, the first measurement for CP asymmetry of $b\to
d\gamma$ process using $B\to\rho\gamma$ mode, and semi-inclusive measurement
for $B\to X_d\gamma$.


title:
Coherent response to optical excitation in a rare-earth ion doped
  crystal

abstract:
  We investigate coherent propagation through a large optical density
Tm$^{3+}$:YAG crystal. Using an ultra-stable laser, fiber filtering and site
selection, we investigate the transmitted pulse temporal profile. The plane
wave condition is satisfied by selection of the illuminated spot central area.
We pay special attention to $\pi$-pulse transmission in the prospect of
implementing optical quantum storage protocols.


title:
New lessons from the nucleon mass, lattice QCD and heavy baryon chiral
  perturbation theory

abstract:
  I will review heavy baryon chiral perturbation theory for the nucleon delta
degrees of freedom and then examine the recent dynamical lattice calculations
of the nucleon mass from the BMW, ETM, JLQCD, LHP, MILC, NPLQCD, PACS-CS,
QCDSF/UKQCD and RBC/UKQCD Collaborations. Performing the chiral extrapolations
of these results, one finds remarkable agreement with the physical nucleon
mass, from each lattice data set. However, a careful examination of the lattice
data and the resulting extrapolation functions reveals some unexpected results,
serving to highlight the significant challenges in performing chiral
extrapolations of baryon quantities. All the N_f=2+1 dynamical results can be
quantitatively described by theoretically unmotivated fit function linear in
the pion mass with m_pi ~ 750 -190 MeV. When extrapolated to the physical
point, the results are in striking agreement with the physical nucleon mass. I
will argue that knowledge of each lattice datum of the nucleon mass is required
at the 1-2% level, including all systematics, in order to conclusively
determine if this is a bizarre conspiracy of lattice artifacts or rather a
mysterious phenomenon of QCD.


title: VERITAS Observations of Mgro J1908+06/Hess J1908+063

abstract:
  The unidentified TeV gamma-ray source MGRO J1908+06/HESS J1908+063 was
observed with the VERITAS Imaging Atmospheric Cherenkov Array during October
2007 and May-June 2008. This extended source is located on the galactic plane
at a galactic longitude of 40.45 degrees and has a hard TeV spectrum with an
index of approximately 2.08. The Very High Energy (VHE) gamma-ray flux was
measured by H.E.S.S. out to energies greater than 30 TeV which along with its
unidentified nature makes it an interesting hard-spectrum extended source for
study. We confirm the detection of VHE gamma-ray emission from this source
using VERITAS.


title:
Metal-insulator transition and strong-coupling spin liquid in the
  $t{-}t^\prime$ Hubbard model

abstract:
  We study the phase diagram of the frustrated $t{-}t^\prime$ Hubbard model on
the square lattice by using a novel variational wave function. Taking the clue
from the backflow correlations that have been introduced long-time ago by
Feynman and Cohen and have been used for describing various interacting systems
on the continuum (like liquid $^3$He, the electron jellium, and metallic
Hydrogen), we consider many-body correlations to construct a suitable
approximation for the ground state of this correlated model on the lattice. In
this way, a very accurate {\it ansatz} can be achieved both at weak and strong
coupling. We present the evidence that an insulating and non-magnetic phase can
be stabilized at strong coupling and sufficiently large frustrating ratio
$t^\prime/t$.


title: On computations of angular momentum and its flux in numerical relativity

abstract:
  The purpose of this note is to point out ambiguities that appear in the
calculation of angular momentum and its radiated counterpart when some simple
formulae are used to compute them. We illustrate, in two simple different
examples, how incorrect results can be obtained with them. Additionally, we
discuss the magnitude of possible errors in well known situations.


title: Synthesis and characterization of multiferroic BiMn$_7$O$_{12}$

abstract:
  We report on the high pressure synthesis of BiMn$_7$O$_{12}$, a manganite
displaying a "quadruple perovskite" structure. Structural characterization of
single crystal samples shows a distorted and asymmetrical coordination around
the Bi atom, due to presence of the $6s^{2}$ lone pair, resulting in
non-centrosymmetric space group Im, leading to a permanent electrical dipole
moment and ferroelectric properties. On the other hand, magnetic
characterization reveals antiferromagnetic transitions, in agreement with the
isostructural compounds, thus evidencing two intrinsic properties that make
BiMn$_7$O$_{12}$ a promising multiferroic material.


title:
Multi-wavelength Observations of LS I +61 303 with VERITAS, Swift and
  RXT E: 2006-2008

abstract:
  A long term, multi-wavelength monitoring campaign on the TeV binary LS I +61
303 has been performed utilizing >300 GeV observations with VERITAS along with
monitoring in the 0.2-10 keV band by RXTE and Swift between September 2006 and
February 2008. The source was detected by VERITAS as a variable TeV source with
flux values ranging from 5-20% of the Crab Nebula flux with the strongest flux
levels appearing around apastron. X-ray observations by RXTE and Swift show the
source as a highly variable hard X-ray source with flux values varying in the
range of 0.5-3*10^-11 ergs cm^-2 s^-1 over a single orbital cycle. The
2007-2008 RXTE data set also shows the presence of several extremely large
flaring episodes presenting a flux of up to 7.2*10^-11 ergs cm^-2 s^-1, the
largest such flare recorded from this source. Comparison of the contemporaneous
TeV and X-ray data does not show a correlation at this time, however, the
sparsity of data sets do not preclude the existence of such a correlation.


title: Brownian motion and the parabolicity of minimal graphs

abstract:
  We prove that minimal graphs (other than planes) are parabolic in the sense
that any bounded harmonic function is determined by its boundary values. The
proof relies on using the coupling introduced in the author's earlier paper "A
martingale approach to minimal surfaces" to show that Brownian motion on such a
minimal graph almost surely strikes the boundary in finite time.


title: Deterministic entanglement of ions in thermal states of motion

abstract:
  We give a detailed description of the implementation of a Molmer-Sorensen
gate entangling two Ca+ ions using a bichromatic laser beam near-resonant with
a quadrupole transition. By amplitude pulse shaping and compensation of
AC-Stark shifts we achieve a fast gate operation without compromising the error
rate. Subjecting different input states to concatenations of up to 21
individual gate operations reveals Bell state fidelities above 0.80. In
principle, the entangling gate does not require ground state cooling of the
ions as long as the Lamb-Dicke criterion is fulfilled. We present the first
experimental evidence for this claim and create Bell states with a fidelity of
0.974(1) for ions in a thermal state of motion with a mean phonon number of
<n>=20(2) in the mode coupling to the ions' internal states.


title:
Quantum mechanics for three versions of the Dirac equation in a curved
  spacetime

abstract:
  We present a recent work on the Dirac equation in a curved spacetime. In
addition to the standard equation, two alternative versions are considered,
derived from wave mechanics, and based on the tensor representation of the
Dirac field. The latter considers the Dirac wave function as a spacetime vector
and the set of the Dirac matrices as a third-order tensor. Having the
probability current conserved for any solution of the Dirac equation gives an
equation to be satisfied by the coefficient fields. A positive definite scalar
product is defined and a hermiticity condition for the Dirac Hamiltonian is
derived for a general coordinate system in a general curved spacetime. For the
standard equation, the hermiticity of the Dirac Hamiltonian is not preserved
under all admissible changes of the coefficient fields.


title:
Background charges and quantum effects in quantum dots transport
  spectroscopy

abstract:
  We extend a simple model of a charge trap coupled to a single-electron box to
energy ranges and parameters such that it gives new insights and predictions
readily observable in many experimental systems. We show that a single
background charge is enough to give lines of differential conductance in the
stability diagram of the quantum dot, even within undistorted Coulomb diamonds.
It also suppresses the current near degeneracy of the impurity charge, and
yields negative differential lines far from this degeneracy. We compare this
picture to two other accepted explanations for lines in diamonds, based
respectively on the excitation spectrum of a quantum dot and on fluctuations of
the density-of-states in the contacts. In order to discriminate between these
models we emphasize the specific features related to environmental charge
traps. Finally we show that our model accounts very well for all the anomalous
features observed in silicon nanowire quantum dots.


title:
Section on Supernova remnants and cosmic rays of the White Paper on the
  Status and Future of Ground-based Gamma-ray Astronomy

abstract:
  This is a report on the findings of the SNR/cosmic-ray working group for the
white paper on the status and future of ground-based gamma-ray astronomy. The
white paper is an APS commissioned document, and the overall version has also
been released and can be found on astro-ph. This detailed section of the white
paper discusses the status of past and current attempts to observe shell-type
supernova remnants and diffuse emission from cosmic rays at GeV-TeV energies.
We concentrate on the potential of future ground-based gamma-ray experiments to
study the acceleration of relativistic charged particles which is one of the
main unsolved, yet fundamental, problems in modern astrophysics. The
acceleration of particles relies on interactions between energetic particles
and magnetic turbulence. In the case of SNRs we can perform spatially resolved
studies in systems with known geometry, and the plasma physics deduced from
these observations will help us to understand other systems where rapid
particle acceleration is believed to occur and where observations as detailed
as those of SNRs are not possible.


title: Packing multiway cuts in capacitated graphs

abstract:
  We consider the following "multiway cut packing" problem in undirected
graphs: we are given a graph G=(V,E) and k commodities, each corresponding to a
set of terminals located at different vertices in the graph; our goal is to
produce a collection of cuts {E_1,...,E_k} such that E_i is a multiway cut for
commodity i and the maximum load on any edge is minimized. The load on an edge
is defined to be the number of cuts in the solution crossing the edge. In the
capacitated version of the problem the goal is to minimize the maximum relative
load on any edge--the ratio of the edge's load to its capacity. Multiway cut
packing arises in the context of graph labeling problems where we are given a
partial labeling of a set of items and a neighborhood structure over them, and,
informally, the goal is to complete the labeling in the most consistent way.
This problem was introduced by Rabani, Schulman, and Swamy (SODA'08), who
developed an O(log n/log log n) approximation for it in general graphs, as well
as an improved O(log^2 k) approximation in trees. Here n is the number of nodes
in the graph. We present the first constant factor approximation for this
problem in arbitrary undirected graphs. Our approach is based on the
observation that every instance of the problem admits a near-optimal laminar
solution (that is, one in which no pair of cuts cross each other).


title:
Spectra and anisotropy of magnetic fluctuations in the Earth's
  magnetosheath: Cluster observations

abstract:
  We investigate the spectral shape, the anisotropy of the wave vector
distributions and the anisotropy of the amplitudes of the magnetic fluctuations
in the Earth's magnetosheath within a broad range of frequencies. We present
the first observations of a Kolmogorov-like inertial range of Alfvenic
fluctuations in the magnetosheath flanks, below fci. In the vicinity of fci, a
spectral break is observed, like in solar wind turbulence. Above the break, the
energy of compressive and Alfvenic fluctuations generally follow a power law
with a spectral index between -3 and -2. Concerning the anisotropy of the wave
vector distribution, we observe a change in its nature in the vicinity of ion
characteristic scales: if at MHD scales there is no evidence for a dominance of
a slab (k||>kperp) or 2D (kperp>k||) turbulence, above the spectral break,
(f>fci, kc/wpi>1) the 2D turbulence dominates. This 2D turbulence is observed
in six selected one-hour intervals among which the average proton beta varies
from 0.8 to 9. It is observed for both the transverse and compressive magnetic
fluctuations, independently on the presence of linearly unstable modes at low
frequencies or Alfven vortices at the spectral break. We then analyse the
anisotropy of the magnetic fluctuations in a time dependent reference frame
based on the field B and the flow velocity V directions. Within the range of
the 2D turbulence, at scales [1,30]kc/wpi, and for any beta we find that the
magnetic fluctuations at a given frequency in the plane perpendicular to B have
more energy along the BxV direction. This non-gyrotropy of the fluctuations is
consistent with gyrotropic fluctuations at a given wave vector, with kperp>k||,
which suffer a different Doppler shift along and perpendicular to V in the
plane perpendicular to B.


title: Reweighting QCD simulations with dynamical overlap fermions

abstract:
  I apply a recently developed algorithm for reweighting simulations of lattice
QCD from one quark mass to another to simulations performed with overlap
fermions in the epsilon regime. I test it by computing the condensate from
distributions of the low lying eigenvalues of the Dirac operator. Results seem
favorable.


title:
On the Purity of the free boundary condition Potts measure on random
  trees

abstract:
  We consider the free boundary condition Gibbs measure of the Potts model on a
random tree. We provide an explicit temperature interval below the
ferromagnetic transition temperature for which this measure is extremal,
improving older bounds of Mossel and Peres. In information theoretic language
extremality of the Gibbs measure corresponds to non-reconstructability for
symmetric q-ary channels. The bounds are optimal for the Ising model and appear
to be close to what we conjecture to be the true values up to a factor of
0.0150 in the case q = 3 and 0.0365 for q = 4. Our proof uses an iteration of
random boundary entropies from the outside of the tree to the inside, along
with a symmetrization argument.


title: Portfolio Optimization under Habit Formation

abstract:
  The "standard" Merton formulation of optimal investment and consumption
involves optimizing the integrated lifetime utility of consumption, suitably
discounted, together with the discounted future bequest. In this formulation
the utility of consumption at any given time depends only on the amount
consumed at that time. However, it is both theoretically and empirically
reasonable that an individuals utility of consumption would depend on past
consumption history. Economists term this "Habit Formation". We introduce a new
formulation of habit formation which allows non-addictive consumption patterns
for a wide variety of utility specification. In this paper we construct a
simple mathematical description of this habit formation and present numerical
solutions. We compare the results with the standard ones and draw insights
obtained from the habit formation. The consumption path tends to increase with
time and be less sensitive to the market fluctuations, which perfectly reflects
the existence of habit persistence of an investor. At the same time, his
decreasing risk aversion, which seems to be in contradiction with the empirical
evidence, can be explained within the limitations of the model.


title:
Magnetic crossover and complex excitation spectrum of the
  ferromagnetic/antiferromagnetic spin-1/2 chain system alpha-TeVO4

abstract:
  We report magnetic susceptibility, specific heat, and Raman scattering
investigations of alpha-TeVO4 containing V-O edge-sharing chains. These chains
promote a system of ferromagnetic/antiferromagnetic spin-1/2 Heisenberg
alternating exchange chains with pronounced spin frustration. The magnetic
susceptibility and Raman scattering evidence a crossover at T* = 85 K with
different slopes of the reciprocal susceptibility and a magnetic phase
transition into a long-range-ordered state at Tc = 16 K. From Raman scattering
data a strong mutual coupling between lattice and magnetic degrees of freedom
is deduced. A comparison to model calculations and prior Raman scattering on
other chain systems yield a plausible interpretation of the microscopic
mechanism for the crossover behavior.


title: The Resonating-Valence-Bond Ground State of Li Nanoclusters

abstract:
  We have performed Diffusion Quantum Monte Carlo simulations of Li clusters
showing that Resonating-Valence-Bond (RVB) pairing correlations between
electrons provide a substantial contribution to the cohesive energy. The RVB
effects are identified in terms of electron transfers from s- to p-like
character, constituting a possible explanation for the breakdown of the Fermi
liquid picture observed in recent high resolution Compton scattering
experiments for bulk Li.


title: Glasses in Colloidal Systems. Attractive Interactions and Gelation

abstract:
  In this chapter, a study of the glass transitions in colloidal systems is
presented, in connection with gelation, mainly from theoretical and simulation
results. Mode Coupling Theory, which anticipated the existence of attraction
driven glasses, is reviewed, and its predictions concerning attractive glasses
discussed. Results from computer simulations will be presented for different
models and the predictions of the theory will be tested. Starting from high
density, where reasonable agreement is found, the study will be extended to low
density, where new modes for the decay of density correlation functions appear.
In all cases, the results will be also be brought into connection with
experiments, and we will conclude with a discussion of the present
understanding of the mechanisms leading to gelation.


title: The Globular Cluster NGC 5286. I. A New CCD BV Color-Magnitude Diagram

abstract:
  We present BV photometry of the Galactic globular cluster NGC 5286, based on
128 V frames and 133 B frames, and covering the entire face of the cluster. Our
photometry reaches almost two magnitudes below the turn-off level, and is
accordingly suitable for an age analysis. Field stars were removed
statistically from the cluster's color-magnitude diagram (CMD), and a
differential reddening correction applied, thus allowing a precise ridgeline to
be calculated.
  Using the latter, a metallicity of [Fe/H] = -1.70 +/- 0.10 in the Zinn & West
scale, and [Fe/H] = -1.47 +/- 0.02 in the Carretta & Gratton scale, was derived
on the basis of several parameters measured from the red giant branch, in good
agreement with the value provided in the Harris catalog.
  Comparing the NGC 5286 CMD with the latest photometry for M3 by P. B. Stetson
(2008, priv. comm.), and using VandenBerg isochrones for a suitable chemical
composition, we find evidence that NGC 5286 is around 1.7 +/- 0.9 Gyr older
than M3. This goes in the right sense to help account for the blue horizontal
branch of NGC 5286, for which we provide a measurement of several morphological
indicators. If NGC 5286 is a bona fide member of the Canis Major dwarf
spheroidal galaxy, as previously suggested, our results imply that the latter's
oldest components may be at least as old as the oldest Milky Way globular
clusters.


title:
Galactic Compact Objects Section of the White Paper on the Status and
  Future of Ground-based TeV Gamma-ray Astronomy

abstract:
  This is a report on the findings of the Galactic compact objects working
group for the white paper on the status and future of TeV gamma-ray astronomy.
The white paper is an APS commissioned document, and the full version has also
been released and can be found on astro-ph. This section of the white paper
discusses the potential of future ground-based gamma-ray experiments to advance
our understanding of the physics of Galactic compact objects including pulsars,
pulsar wind nebulae, and X-ray binaries.


title: Mathematical justification of the Aharonov-Bohm hamiltonian

abstract:
  It is presented, in the framework of nonrelativistic quantum mechanics, a
justification of the usual Aharonov-Bohm hamiltonian (with solenoid of radius
greater than zero). This is obtained by way of increasing sequences of finitely
long solenoids together with a natural impermeability procedure; further, both
limits commute. Such rigorous limits are in the strong resolvent sense and in
both $\R^2$ and $\R^3$ spaces.


title:
Critical and multicritical behavior of the +- J Ising model in two and
  three dimensions

abstract:
  We report our Monte Carlo results on the critical and multicritical behavior
of the +- J Ising model [with a random-exchange probability P(J_{xy}) = p
\delta(J_{xy} - J) + (1-p) \delta(J_{xy} + J)], in two and three dimensions. We
study the transition line between the paramagnetic and ferromagnetic phase,
which extends from p=1 to a multicritical (Nishimori) point. By a finite-size
scaling analysis, we provide strong numerical evidence that in three dimensions
the critical behavior along this line belongs to the same universality class as
that of the critical transition in the randomly dilute Ising model. In two
dimensions we confirm that the critical behavior is controlled by the pure
Ising fixed point and that disorder is marginally irrelevant, giving rise to
universal logarithmic corrections. In both two and three dimensions, we also
determine the location of the multicritical Nishimori point, as well as the
renormalization-group dimensions of the operators that control the
renormalization-group flow close to it.


title: Stability of a Bose-Einstein condensate revisited for composite bosons

abstract:
  It is known that elementary bosons condense in a unique state, not so much
because this state has the lowest free particle energy but because it costs a
macroscopic amount of energy to put the particles into different states which
can then interact through quantum particle exchanges. Since individual
exchanges between the two fermions of a composite boson are ignored when
composite particles are replaced by elementary bosons, it is of importance to
reconsider the exchange energy argument for the stability of the Bose-Einstein
condensate in the case of composite bosons. We do this here in the light of the
new many-body theory which allows us to take exactly into account all possible
exchanges between the fermionic components of the composite bosons. We confirm
that the condensate of composite bosons is made of a unique state, this state
being moreover pure: a coherent superposition of states close in energy is
shown to be less favorable for both elementary and composite bosons.


title: Bordered Heegaard Floer homology: Invariance and pairing

abstract:
  We construct Heegaard Floer theory for 3-manifolds with connected boundary.
The theory associates to an oriented, parametrized two-manifold a differential
graded algebra. For a three-manifold with parametrized boundary, the invariant
comes in two different versions, one of which (type D) is a module over the
algebra and the other of which (type A) is an A-infinity module. Both are
well-defined up to chain homotopy equivalence. For a decomposition of a
3-manifold into two pieces, the A-infinity tensor product of the type D module
of one piece and the type A module from the other piece is HF^ of the glued
manifold.
  As a special case of the construction, we specialize to the case of
three-manifolds with torus boundary. This case can be used to give another
proof of the surgery exact triangle for HF^. We relate the bordered Floer
homology of a three-manifold with torus boundary with the knot Floer homology
of a filling.


title: Regular functions on covers of nilpotent coadjoint orbits

abstract:
  In this paper I explore the relationship between regular functions associated
to local systems on nilpotent orbits and unipotent representations in the
complex groups.


title:
Crystal Growth in the Presence of Surface Melting and Impurities: An
  Explanation of Snow Crystal Growth Morphologies

abstract:
  We examine the molecular dynamics of crystal growth in the presence of
surface melting and surface impurities, and from this propose a detailed
microscopic model for the growth of ice from the vapor phase. Our model
naturally accounts for many aspects of the experimental data that are otherwise
difficult to explain, and it suggests a variety of measurements that can
provide further confirmation. Although additional work is needed to refine
these ideas, we believe that the combined influences of surface melting and
impurities provide a viable solution to the 60-year-old mystery of why snow
crystal morphologies vary so dramatically with temperature.


title: A recursive presentation for Mihailova's subgroup

abstract:
  We give an explicit recursive presentation for Mihailova's subgroup $M(H)$ of
$F_n \times F_n$ corresponding to a finite, concise and Peiffer aspherical
presentation $H=< x_1,..., x_n \mid R_1,..., R_m>$. This partially answers a
question of R.I. Grigorchuk, [8, Problem 4.14]. As a corollary, we construct a
finitely generated recursively presented orbit undecidable subgroup of
$Aut(F_3)$.


title: Analytic three-loop Solutions for N=4 SYM Twist Operators

abstract:
  We introduce a method to obtain the analytic solution of the higher-order
Baxter equation for twist-two and twist-three operators of planar N=4 SYM. Our
result proofs the conjectured formula for the three-loop anomalous dimension of
twist-two operators. As such we derive the maximally transcendental part of the
corresponding three-loop QCD result from the maximal supersymmetric gauge
theory in four dimension purely by methods of integrability.


title:
Non-thermal emission from Galaxy Clusters and future observations with
  the FERMI gamma-ray telescope and LOFAR

abstract:
  FERMI (formely GLAST) and LOFAR will shortly provide crucial information on
the non-thermal components (relativistic particles and magnetic field) in
galaxy clusters. After discussing observational facts that already put
constraints on the properties and origin of non-thermal components, I will
report on the emission spectrum from galaxy clusters as expected in the context
of general calculations in which relativistic particles (protons and secondary
electrons due to proton-proton collisions) interact with MHD turbulence
generated in the cluster volume during cluster-cluster mergers. In this
scenario (known as re-acceleration scenario) diffuse cluster-scale radio
emission is produced in massive clusters during merging events, while gamma ray
emission, at some level, is expected to be common in clusters. Expectations of
interest for LOFAR and FERMI are also briefly discussed.


title:
Oracularization and Two-Prover One-Round Interactive Proofs against
  Nonlocal Strategies

abstract:
  A central problem in quantum computational complexity is how to prevent
entanglement-assisted cheating in multi-prover interactive proof systems. It is
well-known that the standard oracularization technique completely fails in some
proof systems under the existence of prior entanglement. This paper studies two
constructions of two-prover one-round interactive proof systems based on
oracularization. First, it is proved that the two-prover one-round interactive
proof system for PSPACE by Cai, Condon, and Lipton still achieves exponentially
small soundness error in the existence of prior entanglement between dishonest
provers (and more strongly, even if dishonest provers are allowed to use
arbitrary no-signaling strategies). It follows that, unless the polynomial-time
hierarchy collapses to the second level, two-prover systems are still
advantageous to single-prover systems even when only malicious provers can use
quantum information. Second, it is proved that the two-prover one-round
interactive proof system obtained by oracularizing a three-query
probabilistically checkable proof system becomes sound in a weak sense even
against dishonest entangled provers with the help of a dummy question. As a
consequence, every language in NEXP has a two-prover one-round interactive
proof system of perfect completeness, albeit with exponentially small gap
between completeness and soundness, in which each prover responds with only two
bits. In other words, it is NP-hard to approximate within an inverse-polynomial
the value of a classical two-prover one-round game, even when provers are
entangled and each sends a two-bit answer to a verifier.


title:
The gluon spin contribution to the proton spin from the double helicity
  asymmetry in inclusive pi^0 production in polarized p+p collisions at
  sqrt(s)=200 GeV

abstract:
  The double helicity asymmetry in neutral pion production for p_T = 1 to 12
GeV/c has been measured with the PHENIX experiment in order to access the gluon
spin contribution, Delta-G, to the proton spin. Measured asymmetries are
consistent with zero, and at a theory scale of \mu^2 = 4 GeV^2 give
Delta-G^[0.02,0.3] = 0.1 to 0.2, with a constraint of -0.7 < Delta-G^[0.02,0.3]
< 0.5 at Delta-chi^2 = 9 (~3 sigma) for our sampled gluon momentum fraction (x)
range, 0.02 to 0.3. The results are obtained using predictions for our measured
asymmetries generated from four representative fits to polarized deep inelastic
scattering data. We also consider the dependence of the Delta-G constraint on
the choice of theoretical scale, a dominant uncertainty in these predictions.


title:
Slicing planar grid diagrams: a gentle introduction to bordered Heegaard
  Floer homology

abstract:
  We describe some of the algebra underlying the decomposition of planar grid
diagrams. This provides a useful toy model for an extension of Heegaard Floer
homology to 3-manifolds with parametrized boundary. This paper is meant to
serve as a gentle introduction to the subject, and does not itself have
immediate topological applications.


title: Gravitational Stability of Boson Stars

abstract:
  We investigate the stability of general-relativistic boson stars by
classifying singularities of differential mappings and compare it with the
results of perturbation theory. Depending on the particle number, the star has
the following regimes of behavior: stable, metastable, pulsation, and collapse.


title: Real Scalar Fields on Manifolds

abstract:
  A generic theory of a single real scalar field is considered, and a simple
method is presented for obtaining a class of solutions to the equation of
motion. These solutions are obtained from a simpler equation of motion that is
generated by replacing a set of the original coordinates by a set of
generalized coordinates, which are harmonic functions in the spacetime. These
ansatz solutions solve the original equation of motion on manifolds that are
defined by simple constraints. These manifolds, and their dynamics, are
independent of the form of the scalar potential. Some scalar field solutions,
and manifolds upon which they exist, are presented for Klein-Gordon and quartic
potentials as examples. Solutions existing on leaves of a foliated space may
allow inferences of the characteristics expected of exact bulk solutions.


title: Dynamically Error-Corrected Gates for Universal Quantum Computation

abstract:
  Scalable quantum computation in realistic devices requires that precise
control can be implemented efficiently in the presence of decoherence and
operational errors. We propose a general constructive procedure for designing
robust unitary gates on an open quantum system without encoding or measurement
overhead. Our results allow for a low-level error correction strategy solely
based on Hamiltonian engineering using realistic bounded-strength controls and
may substantially reduce implementation requirements for fault-tolerant quantum
computing architectures.


title:
Small anisotropy, weak thermal fluctuations, and high field
  superconductivity in Co-doped iron pnictide Ba(Fe1-xCox)2As2

abstract:
  We performed high-field magnetotransport and magnetization measurements on a
single crystal of the 122-phase iron pnictide Ba(Fe1-xCox)2As2. Unlike the HTS
cuprates and 1111-phase oxypnictides, Ba(Fe1-xCox)2As2 showed practically no
broadening of the resistive transitions under magnetic fields up to 45 T. The
mass anisotropy gamma = Hc2ab/Hc2c deduced from the slopes of the upper
critical field dHc2ab/dT = 4.9T/K and dHc2c/dT = 2.5T/K decreases from ~2 near
Tc, to ~1.5 at lower temperatures. We observed the irreversibility field close
to Hc2, and a rather unusual symmetric volume pinning force curve Fp(H)
suggestive of strong pinning nano-structure.


title: Universal Extra Dimension models with right-handed neutrinos

abstract:
  Relic abundance of dark matter is investigated in the framework of universal
extra dimension (UED) models with right-handed neutrinos. These models are free
from the KK graviton problem in the minimal UED model. The first KK particle of
the right-handed neutrino is a dark matter candidate in this framework. When
ordinary neutrino masses are large enough such as the degenerate mass spectrum
case, the dark matter relic abundance can increase significantly. The scale of
the extra dimension consistent with cosmological observations can be 500 GeV in
the minimal setup of UED models with right-handed neutrinos.


title:
Inclusive cross section and double helicity asymmetry for pi^0
  production in p+p collisions at sqrt(s) = 62.4 GeV

abstract:
  The PHENIX experiment presents results from the RHIC 2006 run with polarized
proton collisions at sqrt(s) = 62.4 GeV for inclusive pi^0 production at
mid-rapidity. Unpolarized cross section results are measured for transverse
momenta p_T = 0.5 to 7 GeV/c. Next-to-leading order perturbative quantum
chromodynamics calculations are compared with the data, and while the
calculations are consistent with the measurements, next-to-leading logarithmic
corrections improve the agreement. Double helicity asymmetries A_LL are
presented for p_T = 1 to 4 GeV/c and probe the higher range of Bjorken_x of the
gluon (x_g) with better statistical precision than our previous measurements at
sqrt(s)=200 GeV. These measurements are sensitive to the gluon polarization in
the proton for 0.06 < x_g < 0.4.


title: Birational aspects of the geometry of M_g

abstract:
  We discuss topics on the geometry of the moduli space of curves. We present a
short proof of the Harris-Mumford theorem on the Kodaira dimension of the
moduli space which replaces the computations on the stack of admissible covers
by a simple study of tautological Koszul bundles on M_g. We also present a
streamlined self-contained account of Verra's recent work on the unirationality
of M_g. Finally, we discuss a proof that the moduli space of curves of genus 22
is of general type. Written for Surveys in Differential Geometry.


title: Anthropic Explanation of the Dark Matter Abundance

abstract:
  I use Bousso's causal diamond measure to make a statistical prediction for
the dark matter abundance, assuming an axion with a large decay constant f_a >>
10^{12} GeV. Using a crude approximation for observer formation, the prediction
agrees well with observation: 30% of observers form in regions with less dark
matter than we observe, while 70% of observers form in regions with more dark
matter. Large values of the dark matter ratio are disfavored by an elementary
effect: increasing the amount of dark matter while holding fixed the baryon to
photon ratio decreases the number of baryons inside one horizon volume. Thus
the prediction is rather insensitive to assumptions about observer formation in
universes with much more dark matter than our own. The key assumption is that
the number of observers per baryon is roughly independent of the dark matter
ratio for ratios near the observed value.


title:
Finite-Size Corrections of the $\mathbb{CP}^3$ Giant Magnons: the
  L\"{u}scher terms

abstract:
  We compute classical and first quantum finite-size corrections to the
recently found giant magnon solutions in two different subspaces of
$\mathbb{CP}^3$. We use the L\"{u}scher approach on the recently proposed exact
S-matrix for $\mathcal{N}=6$ superconformal Chern-Simons theory. We compare our
results with the string and algebraic curve computations and find agreement,
thus providing a non-trivial test for the new $AdS_4/CFT_3$ correspondence
within an integrability framework.


title: Domain Walls in a Tetragonal Chiral p-Wave Superconductor

abstract:
  Domain walls in a tetragonal chiral p-wave superconductors with broken time
reversal symmetry are analyzed in the framework of the Ginsburg-Landau theory.
The energy and the jump of the magnetic induction on the wall were determined
for different types of walls as functions of the parameters of the
Ginzburg-Landau theory and orientation of the domain wall with respect to the
crystallographic axes. We discuss implications of the analysis for
$Sr_{2}RuO_{4}$, where no stray magnetic fields from domain walls were detected
experimentally.


title:
On the fundamental group of II_1 factors and equivalence relations
  arising from group actions

abstract:
  Given a countable group G, we consider the sets S_factor(G), S_eqrel(G), of
subgroups F of the positive real line for which there exists a free ergodic
probability measure preserving action G on X such that the fundamental group of
the associated II_1 factor, respectively orbit equivalence relation, equals F.
We prove that if G is the free product of Z and infinitely many copies of a
non-trivial group \Gamma, then S_factor(G) and S_eqrel(G) contain R_+ itself,
all of its countable subgroups, as well as uncountable subgroups whose log can
have any Hausdorff dimension in the interval (0,1). We then prove that if
G=\Gamma*\Lambda, with \Gamma, \Lambda finitely generated ICC groups, one of
which has property (T), then S_factor(G)=S_eqrel(G)={1}. We also show that
there exist II_1 factors M such that the fundamental group of M is R_+, but the
associated II_\infty factor M tensor B(l^2) admits no continuous trace scaling
action of R_+.


title: Curve Flows and Solitonic Hierarchies Generated by Einstein Metrics

abstract:
  We investigate bi-Hamiltonian structures and mKdV hierarchies of solitonic
equations generated by (semi) Riemannian metrics and curve flows of
non-stretching curves. There are applied methods of the geometry of
nonholonomic manifolds enabled with metric-induced nonlinear connection
(N-connection) structure. On spacetime manifolds, we consider a nonholonomic
splitting of dimensions and define a new class of liner connections which are
'N-adapted', metric compatible and uniquely defined by the metric structure. We
prove that for such a linear connection, one yields couples of generalized
sine-Gordon equations when the corresponding geometric curve flows result in
solitonic hierarchies described in explicit form by nonholonomic wave map
equations and mKdV analogs of the Schrodinger map equation. All geometric
constructions can be re-defined for the Levi-Civita connection but with
"noholonomic mixing" of solitonic interactions. Finally, we speculate why
certain methods and results from the geometry of nonholonmic manifolds and
solitonic equations have general importance in various directions of modern
mathematics, geometric mechanics, fundamental theories in physics and
applications, and briefly analyze possible nonlinear wave configurations for
modeling gravitational interactions by effective continuous media effects.


title: Forming Early-type Galaxies in Groups Prior to Cluster Assembly

abstract:
  We study a unique proto-cluster of galaxies, the supergroup SG1120-1202. We
quantify the degree to which morphological transformation of cluster galaxies
occurs prior to cluster assembly in order to explain the observed early-type
fractions in galaxy clusters at z=0. SG1120-1202 at z~0.37 is comprised of four
gravitationally bound groups that are expected to coalesce into a single
cluster by z=0. Using HST ACS observations, we compare the morphological
fractions of the supergroup galaxies to those found in a range of environments.
We find that the morphological fractions of early-type galaxies (~60 %) and the
ratio of S0 to elliptical galaxies (0.5) in SG1120-1202 are very similar to
clusters at comparable redshift, consistent with pre-processing in the group
environment playing the dominant role in establishing the observed early-type
fraction in galaxy clusters.


title: Dark Matter in the Galaxy Cluster CL J1226+3332 at Z=0.89

abstract:
  We present a weak-lensing analysis of the galaxy cluster CL J1226+3332 at
z=0.89 using Hubble Space Telescope Advanced Camera for Surveys images. The
cluster is the hottest (>10 keV), most X-ray luminous system at z>0.6 known to
date. The relaxed X-ray morphology, as well as its high temperature, is unusual
at such a high redshift. Our mass reconstruction shows that on a large scale
the dark matter distribution is consistent with a relaxed system with no
significant substructures. However, on a small scale the cluster core is
resolved into two mass clumps highly correlated with the cluster galaxy
distribution. The dominant mass clump lies close to the brightest cluster
galaxy whereas the other less massive clump is located ~40" (~310 kpc) to the
southwest. Although this secondary mass clump does not show an excess in the
X-ray surface brightness, the gas temperature of the region is much higher
(12~18 keV) than those of the rest. We propose a scenario in which the less
massive system has already passed through the main cluster and the X-ray gas
has been stripped during this passage. The elongation of the X-ray peak toward
the southwestern mass clump is also supportive of this possibility. We measure
significant tangential shears out to the field boundary (~1.5 Mpc), which are
well described by an Navarro-Frenk-White profile with a concentration parameter
of c200=2.7+-0.3 and a scale length of rs=78"+-19" (~600 kpc) with
chi^2/d.o.f=1.11. Within the spherical volume r200=1.6 Mpc, the total mass of
the cluster becomes M(r<r200)=(1.4+-0.2) x 10^15 solar mass. Our weak-lensing
analysis confirms that CL1226+3332 is indeed the most massive cluster known to
date at z>0.6.


title:
The Highly Unusual Chemical Composition of the Hercules Dwarf Spheroidal
  Galaxy

abstract:
  We report on the abundance analysis of two red giants in the faint Hercules
dwarf spheroidal (dSph) galaxy. These stars show a remarkable deficiency in the
neutron-capture elements, while the hydrostatic alpha-elements (O, Mg) are
strongly enhanced. Our data indicate [Ba/Fe] and [Mg/Fe] abundance ratios of
<-2 dex and ~+0.8 dex, respectively, with essentially no detection of other
n-capture elements. In contrast to the only other dSph star with similar
abundance patterns, Dra 119, which has a very low metallicity at [Fe/H]=-2.95
dex, our objects, at [Fe/H]~-2.0 dex, are only moderately metal poor. The
measured ratio of hydrostatic/explosive alpha-elements indicates that high-mass
(~35 M_sun) Type II supernovae progenitors are the main, if not only,
contributors to the enrichment of this galaxy. This suggests that star
formation and chemical enrichment in the ultrafaint dSphs proceeds
stochastically and inhomogeneously on small scales, or that the IMF was
strongly skewed to high mass stars. The neutron capture deficiencies and the
[Co/Fe] and [Cr/Fe] abundance ratios in our stars are similar to those in the
extremely low metallicity Galactic halo. This suggests that either our stars
are composed mainly of the ejecta from the first, massive, population III stars
(but at moderately high [Fe/H]), or that SN ejecta in the Hercules galaxy were
diluted with ~30 times less hydrogen than typical for extreme metal-poor stars.


title:
A Spectacular H$\alpha$ Complex in Virgo: Evidence for a Collision
  Between M86 and NGC 4438 and Implications for Collisional ISM Heating of
  Ellipticals

abstract:
  Deep wide-field H$\alpha$+[NII] imaging around the Virgo cluster giant
elliptical galaxy M86 reveals a highly complex and disturbed ISM/ICM. The most
striking feature is a set of H$\alpha$ filaments which clearly connect M86 with
the nearby disturbed spiral NGC 4438 (23$'$=120 kpc projected away), providing
strong evidence for a previously unrecognized collision between them.
Spectroscopy of selected regions show a fairly smooth velocity gradient between
M86 and NGC 4438, consistent with the collision scenario. Such a collision
would impart significant energy into the ISM of M86, probably heating the gas
and acting to prevent the gas from cooling to form stars. We propose that cool
gas stripped from NGC 4438 during the collision and deposited in its wake is
heated by shocks, ram pressure drag, or thermal conduction, producing most of
the H$\alpha$ filaments. Some H$\alpha$ filaments are associated with the
well-known ridge of bright X-ray emission to the NW of the nucleus, suggesting
that the collision is responsible for peculiarities of M86 previously ascribed
to other effects. M86 is radio-quiet, thus AGN heating is unlikely to play a
significant role. The M86 system has implications for understanding the role of
gravitational interactions in the heating of the ISM in ellipticals, and how
collisions in clusters transform galaxies.


title:
Lifetime of metastable states and suppression of noise in
  Interdisciplinary Physical Models

abstract:
  Transient properties of different physical systems with metastable states
perturbed by external white noise have been investigated. Two noise-induced
phenomena, namely the noise enhanced stability and the resonant activation, are
theoretically predicted in a piece-wise linear fluctuating potential with a
metastable state. The enhancement of the lifetime of metastable states due to
the noise, and the suppression of noise through resonant activation phenomenon
will be reviewed in models of interdisciplinary physics: (i) dynamics of an
overdamped Josephson junction; (ii) transient regime of the noisy
FitzHugh-Nagumo model; (iii) population dynamics.


title: A Theory of Dark Matter

abstract:
  We propose a comprehensive theory of dark matter that explains the recent
proliferation of unexpected observations in high-energy astrophysics. Cosmic
ray spectra from ATIC and PAMELA require a WIMP with mass M_chi ~ 500 - 800 GeV
that annihilates into leptons at a level well above that expected from a
thermal relic. Signals from WMAP and EGRET reinforce this interpretation. Taken
together, we argue these facts imply the presence of a GeV-scale new force in
the dark sector. The long range allows a Sommerfeld enhancement to boost the
annihilation cross section as required, without altering the weak scale
annihilation cross section during dark matter freezeout in the early universe.
If the dark matter annihilates into the new force carrier, phi, its low mass
can force it to decay dominantly into leptons. If the force carrier is a
non-Abelian gauge boson, the dark matter is part of a multiplet of states, and
splittings between these states are naturally generated with size alpha m_phi ~
MeV, leading to the eXciting dark matter (XDM) scenario previously proposed to
explain the positron annihilation in the galactic center observed by the
INTEGRAL satellite. Somewhat smaller splittings would also be expected,
providing a natural source for the parameters of the inelastic dark matter
(iDM) explanation for the DAMA annual modulation signal. Since the Sommerfeld
enhancement is most significant at low velocities, early dark matter halos at
redshift ~10 potentially produce observable effects on the ionization history
of the universe, and substructure is more detectable than with a conventional
WIMP. Moreover, the low velocity dispersion of dwarf galaxies and Milky Way
subhalos can greatly increase the substructure annihilation signal.


title: LHC Signals for a SuperUnified Theory of Dark Matter

abstract:
  A new theory of WIMP Dark Matter has been proposed, motivated directly by
striking Data from the PAMELA and ATIC collaborations. The WIMP is taken to be
charged under a hidden gauge symmetry G_Dark, broken near the GeV scale; this
also provides the necessary ingredients for the "exciting" and "inelastic" Dark
Matter interpretations of the INTEGRAL and DAMA signals. In this short note we
point out the consequences of the most straightforward embedding of this simple
picture within low-energy SUSY, in which G_Dark breaking at the GeV scale
arises naturally through radiative corrections, or Planck-suppressed operators.
The theory predicts major additions to SUSY signals at the LHC. A completely
generic prediction is that G_Dark particles can be produced in cascade decays
of MSSM superpartners, since these end with pairs of MSSM LSP's that in turn
decay into the true LSP and other particles in the dark sector. In turn, the
lightest GeV-scale dark Higgses and gauge bosons eventually decay back into
light SM states, and dominantly into leptons. Therefore, a large fraction of
all SUSY events will contain at least two ``lepton jets'': collections of n>= 2
leptons, with small angular separations and GeV scale invariant masses.
Furthermore, if the Dark Matter sector is directly charged under the Standard
Model, the success of gauge coupling unification implies the presence of new
long-lived colored particles that can be copiously produced at the LHC.


title: Fixed Points of Nonlinear Sigma Models in d>2

abstract:
  Using Wilsonian methods, we study the renormalization group flow of the
Nonlinear Sigma Model in any dimension $d$, restricting our attention to terms
with two derivatives. At one loop we always find a Ricci flow. When symmetries
completely fix the internal metric, we compute the beta function of the single
remaining coupling, without any further approximation. For $d>2$ and positive
curvature, there is a nontrivial fixed point, which could be used to define an
ultraviolet limit, in spite of the perturbative nonrenormalizability of the
theory. Potential applications are briefly mentioned.


title: Methods for the Study of Transverse Momentum Differential Correlations

abstract:
  We introduce and compare three differential correlation functions for the
study of transverse momentum correlation in $p+p$ and $A+A$ collisions. These
consist of {\it inclusive}, {\it event-wise} and a differential version of the
correlation measure $\tilde C$ introduced by Gavin \cite{Gavin} for
experimental study of the viscosity per unit entropy of the matter produced in
$A+A$ collisions. We study the quantitative difference between the three
observables on the basis of PYTHIA simulations of $p+p$ collisions and $A+A$
collisions consisting of an arbitrary superposition of $p+p$ collision events
at $\sqrt{s} = $200 GeV. We observe that {\it inclusive} and {\it event-wise}
correlation functions are remarkably identical to each other where as the
observable $\tilde C$ differs from the two. We study the robustness and
efficiency dependencies of these observables based on truncated Taylor
expansions in efficiency in $p+p$ collisions and on the basis of Monte Carlo
simulation using an adhoc detector efficiency parameterization. We find that
all the three observables are essentially independent of detector efficiency.
We additionally study the scaling of the correlation measures and find all the
observables exhibit an approximate $1/N$ dependence of the number of
participants ({\it N}) in $A+A$ collisions. Finally, we study the impact of
flow-like anisotropy on the {\it inclusive} correlation function and find flow
imparts azimuthal modulations similar to those observed with two-particle
densities.


title: Vortex interactions in a thin platelet superconductor

abstract:
  The thermal fluctations of vortices in a superconductor can be usefully
mapped onto the quantum fluctations of a collection of bosons at T=0 moving in
2 dimensions. When the superconductor is a thin platelet with the magnetic
field parallel to its surface, the interacting quantum bosons are effectively
moving in 1 dimension, allowing for powerful Luttinger liquid methods to be
applied. Here we consider how this 1 dimensional limit is approached, studying
the interaction of vortices with the platelet surfaces and each other. Using
realistic parameters and vortex interactions for an underdoped YBCO platelet we
determine the scattering length, a, characterizing the low energy interaction
of a vortex pair as a function of the platelet thickness. a determines the
Luttinger parameter, g, for the quantum system at low densities, n_0: g ->
1-2an_0.


title:
Statistics of incomplete quotients of continued fractions of quadratic
  irrationalities

abstract:
  V.I. Arnold has experimentally established that the limit of the statistics
of incomplete quotients of partial continued fractions of quadratic
irrationalities coincides with the Gauss--Kuz'min statistics. Below we briefly
prove this fact for roots of the equation $r x^2+p x=q$ with fixed $p$ and $r$
($r>0$), and with random $q$, $q\le R$, $R\to \infty$. In Section 3 we estimate
the sum of incomplete quotients of the period. According to the obtained bound,
prior to the passage to the limit, incomplete quotients in average are
logarithmically small. We also upper estimate the proportion of the "red"
numbers among those representable as a sum of two squares.


title: Code C# for chaos analysis of relativistic many-body systems

abstract:
  This work presents a new Microsoft Visual C# .NET code library, conceived as
a general object oriented solution for chaos analysis of three-dimensional,
relativistic many-body systems. In this context, we implemented the Lyapunov
exponent and the "fragmentation level" (defined using the graph theory and the
Shannon entropy). Inspired by existing studies on billiard nuclear models and
clusters of galaxies, we tried to apply the virial theorem for a simplified
many-body system composed by nucleons. A possible application of the "virial
coefficient" to the stability analysis of chaotic systems is also discussed.


title: Chasing highly obscured QSOs in the COSMOS field

abstract:
  (abridged) We take advantage of the deep Chandra and Spitzer coverage of a
large area (more than 10 times the area covered by the Chandra deep fields,
CDFs in the COSMOS field, to extend the search of highly obscured,
Compton-thick active nuclei to higher luminosity. These sources have low
surface density and large samples can be provided only through large area
surveys, like the COSMOS survey. We analyze the X-ray properties of COSMOS MIPS
sources with 24$\mu$m fluxes higher than 550$\mu$Jy. For the MIPS sources not
directly detected in the Chandra images we produce stacked images in soft and
hard X-rays bands. To estimate the fraction of Compton-thick AGN in the MIPS
source population we compare the observed stacked count rates and hardness
ratios to those predicted by detailed Monte Carlo simulations including both
obscured AGN and star-forming galaxies. The density of lower luminosity
Compton-thick AGN (logL(2-10keV)=43.5-44) at z=0.7--1.2 is $(3.7\pm1.1)
\times10^{-5}$ Mpc$^{-3}$, corresponding to $\sim67%$ of that of X-ray selected
AGN. The comparison between the fraction of infrared selected, Compton thick
AGN to the X-ray selected, unobscured and moderately obscured AGN at high and
low luminosity suggests that Compton-thick AGN follow a luminosity dependence
similar to that discovered for Compton-thin AGN, becoming relatively rarer at
high luminosities. We estimate that the fraction of AGN (unobscured, moderately
obscured and Compton thick) to the total MIPS source population is $49\pm10%$,
a value significantly higher than that previously estimated at similar 24$\mu$m
fluxes. We discuss how our findings can constrain AGN feedback models.


title:
Towards Exact Quantum Loop Results in the Theory of General Relativity:
  Status and Update

abstract:
  We present the status and update of a new approach to quantum general
relativity as formulated by Feynman from the Einstein-Hilbert action wherein
amplitude-based resummation techniques are applied to the theory's loop
corrections to yield results (superficially) free of ultraviolet(UV)
divergences. Recent applications are summarized.


title: Nuclear scattering of dark matter coupled to a new light scalar

abstract:
  We consider the nuclear scattering cross section for the eXciting Dark Matter
(XDM) model. In XDM, the Weakly Interacting Massive Particles (WIMPs) couple to
the Standard Model only via an intermediate light scalar which mixes with the
Higgs: this leads to a suppression in the nuclear scattering cross section
relative to models in which the WIMPs couple to the Higgs directly. We estimate
this suppression factor to be of order 10^(-5). The elastic nuclear scattering
cross section for XDM can also be computed directly: we perform this
computation for XDM coupled to the Higgs sector of the Standard Model and find
a spin-independent cross section in the order of 4 x 10^(-13) pb in the
decoupling limit, which is not within the range of any near-term direct
detection experiments. However, if the XDM dark sector is instead coupled to a
two-Higgs-doublet model, the spin-independent nuclear scattering cross section
can be enhanced by up to four orders of magnitude for large tan(beta), which
should be observable in the upcoming SuperCDMS and ton-scale xenon experiments.


title:
Precision QED \otimes QCD Resummation Theory for LHC Physics:
  IR-Improved Scheme for Parton Distributions, Kernels, Reduced Cross Sections
  with Shower/ME Matching

abstract:
  We summarize the recent progress in a new approach to precision LHC physics
based on the IR-improved DGLAP-CS theory as it relates to a new MC friendly
exponentiated scheme for precision calculation of higher order corrections to
LHC physics in which IR singularities from both QED and QCD are canceled to all
orders in \alpha and in \alpha_s simultaneously in the presence of rigorous
shower/ME matching. We present the first MC data comparing the implied new
showers themselves with the standard ones using the HERWIG6.5 MC event
generator as a test case at LHC energies.


title: A negative mass theorem for surfaces of positive genus

abstract:
  We define the "sum of squares of the wavelengths" of a Riemannian surface
(M,g) to be the regularized trace of the inverse of the Laplacian. We normalize
by scaling and adding a constant, to obtain a "mass", which is scale invariant
and vanishes at the round sphere. This is an anlaog for closed surfaces of the
ADM mass from general relativity. We show that if M has positive genus then on
each conformal class, the mass attains a negative minimum. For the minimizing
metric, there is a sharp logarithmic Hardy-Littlewood-Sobolev inequality and a
Moser-Trudinger-Onofri type inequality.


title: BCOV theory via Givental group action on cohomological field theories

abstract:
  In a previous paper (arXiv:0704.1001), Losev, me, and Shneiberg constructed a
full descendant potential associated to an arbitrary cyclic Hodge dGBV algebra.
This contruction extended the construction of Barannikov and Kontsevich of
solution of the WDVV equation, based on the earlier paper of Bershadsky,
Cecotti, Ooguri, and Vafa. In the present paper, we give an interpretation of
this full descendant potential in terms of Givental group action on
cohomological field theories. In particular, the fact that it satisfies all
tautological equations becomes a trivial observation.


title:
Fractional Quantum Hall Effect States on a Torus show a Liquid Insulator
  Direct Transition

abstract:
  From the Fractional Quantum Hall Effect States on a torus with filling factor
nu = 1/p, p odd, we found that for small values of nu such states describe
triangular Wigner crystals which are stable configurations. Therefore, the
insulator phase of the two-dimensional electron system can be described with
the same wave function that the liquid phase, and the incompressible liquid
freezes (or the Wigner crystal melts) without any quantum transition between
states, thus the system phase changes by means of a direct transition. We found
at least one stable configuration of a Wigner crystal with F = 3 electrons for
cell and we investigate the behavior of the crystal when the lengths ratio
Ly/Lx changes.


title: Finiteness and the Higgs mass prediction

abstract:
  Finite Unified Theories (FUTs) are N=1 supersymmetric Grand Unified Theories
(GUTs) which can be made finite to all-loop orders, leading to a drastic
reduction in the number of free parameters. By confronting the predictions of
SU(5) FUTs with the top and bottom quark masses we are able to discriminate
among different models. Including further low-energy phenomenology constraints,
such as B physics observables, the bound on the SM Higgs mass and the cold dark
matter density, we derive predictions for the lightest Higgs boson mass and the
sparticle spectrum.


title: A primer on Seshadri constants

abstract:
  Seshadri constants express the so called local positivity of a line bundle on
a projective variety. They were introduced by Demailly. The original idea of
using them towards a proof of the Fujita conjecture failed but they quickly
became a subject of intensive study quite in their own right. Lazarsfeld's book
"Positivity in Algebraic Geometry" contains a whole chapter devoted to local
positivity and serves as a very enjoyable introduction to Seshadri constants.
Since this book has appeared, the subject witnessed quite a bit of development.
It is the aim of these notes to give an account of recent progress as well as
to discuss many open questions and provide some examples.


title: On the structure of Goulden-Jackson-Vakil formula

abstract:
  We study the structure of the Goulden-Jackson-Vakil formula that relates
Hurwitz numbers to some conjectural "intersection numbers" on a conjectural
family of varieties $X_{g,n}$ of dimension $4g-3+n$. We give explicit formulas
for the properly arranged generating function for these "intersection numbers",
and prove that it satisfies Hirota equations. This generalizes and
substantially simplifies our earlier results with Zvonkine in
arXiv:math/0602457.


title: Multi-hadron operators with all-to-all quark propagators

abstract:
  Hadron spectroscopy on dynamical configurations are faced with the
difficulties of dealing with the mixing of single particle states and
multi-hadron states (for large spatial volumes and light dynamical quarks
masses). It is conceivable that explicit multi-hadron interpolating operators
will be necessary for obtaining sufficiently good overlap onto multi-hadron
states in order to extract the low-lying excitation spectrum. We explore here
the feasibility of using four noise diluted all-to-all quark propagators in the
construction of explicit two-hadron operators on quenched, anisotropic
lattices. Our longer term goal is to use these operators on large anisotropic,
dynamical configurations for hadron spectroscopy.


title: A naive parametrization for the vortex-sheet problem

abstract:
  We consider the dynamics of a vortex sheet that evolves by the Birkhoff-Rott
equations. The fluid evolution is understood as a weak solution of the
incompressible Euler equations where the vorticity is given by a delta function
on a curve multiplied by an amplitude. The solutions we study are with finite
energy, which implies zero mean amplitude. In this context we choose a
parametrization for the motion of the vortex sheet for which the equation is
well-posed for analytic initial data. For the equation of the amplitude we show
ill-posedness for non-analytic initial data.


title: A note on Elkin's improvement of Behrend's construction

abstract:
  We provide a short proof of a recent result of Elkin in which large subsets
of the integers 1 up to N free of 3-term progressions are constructed.


title: Morley sequences in dependent theories

abstract:
  We characterize nonforking (Morley) sequences in dependent theories in terms
of a generalization of Poizat's special sequences and show that average types
of Morley sequences are stationary over their domains. We characterize
generically stable types in terms of the structure of the "eventual" type. We
then study basic properties of "strict Morley sequences", based on Shelah's
notion of strict nonforking. In particular we prove "Kim's lemma" for such
sequences, and a weak version of local character.


title: Unstable classes of metric structures

abstract:
  We prove a strong non-structure theorem for a class of metric structures with
an unstable pair of formulae. As a consequence, we show that weak categoricity
(that is, categoricity up to isomorphisms and not isometries) implies several
versions of stability. This is the first step in the direction of the
investigation of weak categoricity and weak stability of metric classes.


title: Soliton dynamics for CNLS systems with potentials

abstract:
  The soliton dynamics in the semiclassical limit for a weakly coupled
nonlinear focusing Schr\"odinger systems in presence of a nonconstant potential
is studied by taking as initial data some rescaled ground state solutions of an
associate elliptic system.


title: A General Fredholm Theory III: Fredholm Functors and Polyfolds

abstract:
  We describe a very general (nonlinear) Fredholm theory for a new class of
ambient spaces, called polyfolds. The basic feature of these new spaces is that
in general they may have locally varying dimensions. These new spaces are
needed for a functional analytic treatment of nonlinear problems involving
analytic limiting behavior. This theory is applicable to Gromov-Witten and
Floer Theory as well as Symplectic Field Theory.