title: Stabilizing moduli with thermal matter and nonperturbative effects

abstract:
  Even with recent progress, it is still very much an open question to
understand how all compactification moduli are stabilized, since there are
several mechanisms. For example, it is possible to generate a scalar potential
either classically or through nonperturbative effects, such as gaugino
condensation. Such a potential can stabilize certain of the moduli fields, for
example the dilaton. On the other hand, a background of thermal matter with
moduli-dependent masses can also stabilize certain of the moduli, e.g., the
radion. It is important to understand whether these two distinct mechanisms are
compatible with each other, that is, that there are no interference terms that
could spoil the moduli stabilization. In this paper, we study heterotic string
theory on an N=1 orbifold near an enhanced symmetry point. We then consider
both a nonperturbatively generated potential and a gas of strings with
moduli-dependent masses to stabilize the dilaton and radial modulus,
respectively. We conclude that, given certain approximations, these two moduli
stabilization mechanisms are compatible.


title:
Low-frequency vacuum squeezing via polarization self-rotation in Rb
  vapor

abstract:
  We observed squeezed vacuum light at 795 nm in 87Rb vapor via resonant
polarization self-rotation, and report noise sidebands suppression of ~1 dB
below shot noise level spanning from acoustic (30 kHz) to MHz frequencies. This
is the first demonstration of sub-MHz quadrature vacuum squeezing in atomic
systems. The spectral range of observed squeezing matches well typical
bandwidths of electromagnetically induced transparency (EIT) resonances, making
this simple technique for generation of optical fields with non-classical
statistics at atomic transitions wavelengths attractive for EIT-based quantum
information protocols applications.


title:
Doping dependence of phonon and quasiparticle heat transport of pure and
  Dy-doped Bi_2Sr_2CaCu_2O_{8+\delta} single crystals

abstract:
  The temperature and magnetic-field (H) dependences of thermal conductivity
(\kappa) of Bi_2Sr_2CaCu_2O_{8+\delta} (Bi2212) are systematically measured for
a broad doping range by using both pure Bi2212 single crystals with tuned
oxygen contents and Bi_2Sr_2Ca_{1-x}Dy_xCu_2O_{8+\delta} (Dy-Bi2212) single
crystals with different Dy contents x. In the underdoped samples, the
quasiparticle (QP) peak below T_c is strongly suppressed, indicating strong QP
scattering by impurities or oxygen defects, whereas the phonon conductivity is
enhanced in moderately Dy-doped samples and a phonon peak at 10 K is observed
for the first time in Bi2212 system, which means Dy^{3+} ions not only
introduce the impurities or point defects but also stabilize the crystal
lattice. The subkelvin data show that the QP heat conductivity gradually
decreases upon lowering the hole doping level. The magnetic-field dependence of
\kappa at temperature above 5 K is mainly due to the QP scattering off
vortices. While the underdoped pure Bi2212 show very weak field dependence of
\kappa, the Dy-doped samples present an additional "dip"-like term of \kappa(H)
at low field, which is discussed to be related to the phonon scattering by free
spins of Dy^{3+} ions. For non-superconducting Dy-Bi2212 samples with x \simeq
0.50, an interesting "plateau" feature shows up in the low-T \kappa(H)
isotherms with characteristic field at 1 -- 2 T, for which we discuss the
possible revlevance of magnon excitations.


title: Dynamical Coupling Between Ferromagnets Due to Spin Transfer Torque

abstract:
  We use a combination of analytic calculations and numerical simulations to
demonstrate that electrical current flowing through a magnetic bilayer induces
dynamical coupling between the layers. The coupling originates from the
dependence of the spin transfer torque exerted on the layers on the relative
orientations of their magnetic moments. We demonstrate that such coupling
modifies the behaviors of both layers, significantly affecting the the
stability of the current-induced dynamical regimes and the efficiency of
current-induced magnetic reversal.


title: Have we tested Lorentz invariance enough?

abstract:
  Motivated by ideas from quantum gravity, Lorentz invariance has undergone
many stringent tests over the past decade and passed every one. Since there is
no conclusive reason from quantum gravity that the symmetry \textit{must} be
violated at some point we should ask the questions: a) are the existing tests
sufficient that the symmetry is already likely exact at the Planck scale? b)
Are further tests simply blind searches for new physics without reasonable
expectation of a positive signal? Here we argue that the existing tests are not
quite sufficient and describe some theoretically interesting areas of existing
parameterizations for Lorentz violation in the infrared that are not yet ruled
out but are accessible (or almost accessible) by current experiments. We
illustrate this point using a vector field model for Lorentz violation
containing operators up to mass dimension six and analyzing how terrestrial
experiments, neutrino observatories, and Auger results on ultra-high energy
cosmic rays limit this model.


title: Some Additional Bounds on the Photon Charge

abstract:
  We have arrived at tight constraints on the photon charge, giving comparable
bounds, one based on the dominance by dark energy at the present epoch, and the
other based on the requirement that early universe nucleosynthesis not be
affected by any residual electrostatic energy due to any miniscule charge on
the radiation photons in that era. Limits have also been arrived at from
synchrotron and IC effects. We have also set limits on the charge based on the
properties of black holes. The set of constraints arrived at in this paper are
consistent with those predicted by other authors.


title: Determination of B*B pi coupling in unquenched QCD

abstract:
  The $B^* B\pi$ coupling is a fundamental parameter of chiral effective
Lagrangian with heavy-light mesons and can constrain the chiral behavior of
$f_B$, $B_B$ and the $B\to \pi l \nu$ form factor in the soft pion limit. We
compute the $B^* B \pi $ coupling with the static heavy quark and the
$O(a)$-improved Wilson light quark. Simulations are carried out with $n_f=2$
unquenched $12^3\times 24$ lattices at $\beta=1.80$ and $16^3\times 32$
lattices at $\beta=1.95$ generated by CP-PACS collaboration. To improve the
statistical accuracy, we employ the all-to-all propagator technique and the
static quark action with smeared temporal link variables following the quenched
study by Negishi {\it et al.}. These methods successfully work also on
unquenched lattices, and determine the $B^*B\pi$ coupling with 1--2%
statistical accuracy on each lattice spacing.


title: Representation theory of W-algebras, II: Ramond twisted representations

abstract:
  We study the Ramond twisted representations of the affine W-algebra W^k(g,f)
in the case that f admits a good even grading. We establish the vanishing and
the almost irreducibility of the corresponding BRST cohomology. This confirms
some of the recent conjectures of Kac and Wakimoto. In type A, our results give
the characters of all irreducible ordinary Ramond twisted representations of
W^k(sl_n,f) for all nilpotent elements f and all non-critical k, and prove the
existence of modular invariant representations conjectured by Kac and Wakimoto.


title:
Generators for Vector Spaces Spanned by Double Zeta Values with Even
  Weight

abstract:
  Let $\mathcal{DZ}_k$ be the $\mathbb{Q}$-vector space spanned by double zeta
values with weight $k$, and $\mathcal{DM}_k$ be its quotient space divided by
the space $\mathcal{PZ}_k$ spanned by the zeta value $\zeta(k)$ and products of
two zeta values with total weight $k$. When $k$ is even, an upper bound for the
dimension of $\mathcal{DM}_k$ is known. By adding the dimensions of
$\mathcal{DM}_k$ and $\mathcal{PZ}_k$, an upper bound of $\mathcal{DZ}_k$ which
equals $k/2$ minus the dimension of the space of modular forms of weight $k$ on
the modular group is given. In this note, we obtain some specific sets of
generators for $\mathcal{DM}_k$ which represent the upper bound. These yield
the corresponding sets and the upper bound for $\mathcal{DZ}_k$.


title:
New assembly route for three-dimensional metamaterials through effect
  medium theory

abstract:
  In this study, we illustrate the effective medium theories in the designs of
three-dimensional composite metametails of both negative permittivity and
permeability. The proposed metamaterials consist of coated spheres embedded in
a dielectric host. Simple design rules and formulas following the effective
medium models are numerically and analytically presented. We demonstrate that
the revised Maxwell-Garnett effective medium theory enables us to design
three-dimensional composite metamaterials through assembly of coated small
spheres. The proposed approach allows for precise control of the permittivity
and permeability and guides a facile, flexible and versatile way for the
fabrication of composite metamaterials.


title: Universal Coding for Lossless and Lossy Complementary Delivery Problems

abstract:
  This paper deals with a coding problem called complementary delivery, where
messages from two correlated sources are jointly encoded and each decoder
reproduces one of two messages using the other message as the side information.
Both lossless and lossy universal complementary delivery coding schemes are
investigated. In the lossless case, it is demonstrated that a universal
complementary delivery code can be constructed by only combining two
Slepian-Wolf codes. Especially, it is shown that a universal lossless
complementary delivery code, for which error probability is exponentially
tight, can be constructed from two linear Slepian-Wolf codes. In the lossy
case, a universal complementary delivery coding scheme based on Wyner-Ziv codes
is proposed. While the proposed scheme cannot attain the optimal
rate-distortion trade-off in general, the rate-loss is upper bounded by a
universal constant under some mild conditions. The proposed schemes allows us
to apply any Slepian-Wolf and Wyner-Ziv codes to complementary delivery coding.


title: Modular varieties of D-elliptic sheaves and the Weil-Deligne bound

abstract:
  We compare the asymptotic grows of the number of rational points on modular
varieties of D-elliptic sheaves over finite fields to the grows of their Betti
numbers as the degree of the level tends to infinity. This is a generalization
to higher dimensions of a well-known result for modular curves. As a
consequence of the main result, we also produce a new asymptotically optimal
sequence of curves.


title: p-wave phase shift and scattering length of $^6$Li

abstract:
  We have calculated the p-wave phase shifts and scattering length of $^6$Li.
For this we solve the $p$ partial wave Schr\"odinger equation and analyze the
validity of adopting the semiclassical solution to evaluate the constant
factors in the solution. Unlike in the $s$ wave case, the semiclassical
solution does not provide unique value of the constants. We suggest an
approximate analytic solution, which provides reliable results in special
cases. Further more, we also use the variable phase method to evaluate the
phase shifts. The p-wave scattering lengths of $^{132}$Cs and $^{134}$Cs are
calculated to validate the schemes followed. Based on our calculations, the
value of the $p$ wave scattering length of $^6$Li is $-45a_o$.


title:
Maximally Informative Stimuli and Tuning Curves for Sigmoidal
  Rate-Coding Neurons and Populations

abstract:
  A general method for deriving maximally informative sigmoidal tuning curves
for neural systems with small normalized variability is presented. The optimal
tuning curve is a nonlinear function of the cumulative distribution function of
the stimulus and depends on the mean-variance relationship of the neural
system. The derivation is based on a known relationship between Shannon's
mutual information and Fisher information, and the optimality of Jeffrey's
prior. It relies on the existence of closed-form solutions to the converse
problem of optimizing the stimulus distribution for a given tuning curve. It is
shown that maximum mutual information corresponds to constant Fisher
information only if the stimulus is uniformly distributed. As an example, the
case of sub-Poisson binomial firing statistics is analyzed in detail.


title: On the eigenvalues of p-adic curvature

abstract:
  We determine the maximal eigenvalue of the p-adic curvature transformations
on Bruhat-Tits buildings, and we give an essentially optimal upper bound on the
minimal non-zero eigenvalue of these transformations.


title:
Production of the charged Higgs bosons at the CERN Large Hadron Collider
  in the left-right symmetric model

abstract:
  We study the production of the charged Higgs boson at the LHC in the
left-right symmetric model. It is shown that there exists a lower bound of the
cross section. We investigate that predicted cross sections of this model are
generally larger than those of the two Higgs doublet model or the minimal
supersymmetric model.


title: Sobolev Institute of Mathematics Celebrates its Fiftieth Anniversary

abstract:
  This paper describes briefly history and current state of the Sobolev
Institute of Mathematics, the biggest research mathematical institute of the
Russian Academy of Sciences located east to Ural mountains.


title: Domain walls in (Ga,Mn)As diluted magnetic semiconductor

abstract:
  We report experimental and theoretical studies of magnetic domain walls in an
in-plane magnetized (Ga,Mn)As dilute moment ferromagnetic semiconductor. Our
high-resolution electron holography technique provides direct images of domain
wall magnetization profiles. The experiments are interpreted based on
microscopic calculations of the micromagnetic parameters and
Landau-Lifshitz-Gilbert simulations. We find that the competition of uniaxial
and biaxial magnetocrystalline anisotropies in the film is directly reflected
in orientation dependent wall widths, ranging from approximately 40 nm to 120
nm. The domain walls are of the N\'eel type and evolve from near-$90^{\circ}$
walls at low-temperatures to large angle [1$\bar{1}$0]-oriented walls and small
angle [110]-oriented walls at higher temperatures.


title:
Bending-Filament Model for the Buckling and Coiling Instability of
  Viscous Fluid Rope

abstract:
  A simple model is proposed for the buckling and coiling instability of a
viscous "fluid rope" falling on a plane. By regarding a fluid rope as a
one-dimensional flow, this model accounts for only the axial and shared viscous
forces. Our model successfully reproduces several experiments with no
adjustable parameters, such as the existence of three distinct coiling regimes
reported in Phys. Rev. Lett. 93, 214502 (2004). Our model allows for the
discussion of unsteady motion. An expression for the critical fall height at
which the coiling frequency changes from a decrease to increase was
phenomenologically derived. It was found that the coil-uncoil transition shows
remarkable hysteresis only for weak gravity condition.


title: Twisted Statistics in kappa-Minkowski Spacetime

abstract:
  We consider the issue of statistics for identical particles or fields in
kappa-deformed spaces, where the system admits a symmetry group G. We obtain
the twisted flip operator compatible with the action of the symmetry group,
which is relevant for describing particle statistics in presence of the
noncommutativity. It is shown that for a special class of realizations, the
twisted flip operator is independent of the ordering prescription.


title: Stability of the Hartree-Fock model with temperature

abstract:
  This paper is devoted to the Hartree-Fock model with temperature in the
euclidean space. For large classes of free energy functionals, minimizers are
obtained as long as the total charge of the system does not exceed a threshold
which depends on the temperature. The usual Hartree-Fock model is recovered in
the zero temperature limit. An orbital stability result for the Cauchy problem
is deduced from the variational approach.


title: Thread extraction for polyadic instruction sequences

abstract:
  In this paper, we study the phenomenon that instruction sequences are split
into fragments which somehow produce a joint behaviour. In order to bring this
phenomenon better into the picture, we formalize a simple mechanism by which
several instruction sequence fragments can produce a joint behaviour. We also
show that, even in the case of this simple mechanism, it is a non-trivial
matter to explain by means of a translation into a single instruction sequence
what takes place on execution of a collection of instruction sequence
fragments.


title:
Kramer-Pesch approximation for analyzing field-angle-resolved
  measurements made in unconventional superconductors: A calculation of the
  zero-energy density of states

abstract:
  By measuring angular-oscillation behavior of the heat capacity with respect
to the applied field direction, one can detect the details of the gap
structure. We introduce the Kramer-Pesch approximation (KPA) as a new method to
analyze the field-angle-dependent experiments quantitatively. We calculate the
zero energy density of states for various combinations of typical Fermi
surfaces and superconducting gaps. The KPA yields a merit that one can
quantitatively compare theoretical calculations with experimental results
without involving heavy numerical computations, even for complicated Fermi
surfaces. We show an inadequacy of the frequently-used Doppler-shift technique,
which is remedied by application of the KPA.


title:
Positive feedback and noise activate the stringent response regulator
  Rel in mycobacteria

abstract:
  Phenotypic heterogeneity in an isogenic, microbial population enables a
subset of the population to persist under stress. In mycobacteria, stresses
like nutrient and oxygen deprivation activate the stress response pathway
involving the two-component system MprAB and the sigma factor, SigE. SigE in
turn activates the expression of the stringent response regulator, rel. The
enzyme polyphosphate kinase 1 (PPK1) regulates this pathway by synthesizing
polyphosphate required for the activation of MprB. The precise manner in which
only a subpopulation of bacterial cells develops persistence, remains unknown.
Rel is required for mycobacterial persistence. Here we show that the
distribution of rel expression levels in a growing population of mycobacteria
is bimodal with two distinct peaks corresponding to low (L) and high (H)
expression states, and further establish that a positive feedback loop
involving the mprAB operon along with stochastic gene expression are
responsible for the phenotypic heterogeneity. Combining single cell analysis by
flow cytometry with theoretical modeling, we observe that during growth,
noise-driven transitions take a subpopulation of cells from the L to the H
state within a "window of opportunity" in time preceding the stationary phase.
We find evidence of hysteresis in the expression of rel in response to changing
concentrations of PPK1. Our results provide, for the first time, evidence that
bistability and stochastic gene expression could be important for the
development of "heterogeneity with an advantage" in mycobacteria.


title: The physical approach to the hot star description

abstract:
  The theoretical discription of a hot star interior is obtained. It explains
the distribution of stars over their masses, mass-radius-temperature and
mass-luminosity dependencies. The theory of the apsidal rotation of binary
stars and the spectrum of solar oscillation is considered. All obrained
theoretical predictions are in a good agreement with the known measurement
data, which confirms the validity of this consideration.


title:
Exact solution of the geometrically frustrated spin-1/2 Ising-Heisenberg
  model on the triangulated Kagome (triangles-in-triangles) lattice

abstract:
  The geometric frustration of the spin-1/2 Ising-Heisenberg model on the
triangulated Kagome (triangles-in-triangles) lattice is investigated within the
framework of an exact analytical method based on the generalized star-triangle
mapping transformation. Ground-state and finite-temperature phase diagrams are
obtained along with other exact results for the partition function, Helmholtz
free energy, internal energy, entropy, and specific heat, by establishing a
precise mapping relationship to the corresponding spin-1/2 Ising model on the
Kagome lattice. It is shown that the residual entropy of the disordered spin
liquid phase is for the quantum Ising-Heisenberg model significantly lower than
for its semi-classical Ising limit (S_0/N_T k_B = 0.2806 and 0.4752,
respectively), which implies that quantum fluctuations partially lift a
macroscopic degeneracy of the ground-state manifold in the frustrated regime.
The investigated model system has an obvious relevance to a series of polymeric
coordination compounds Cu_9X_2(cpa)_6 (X=F, Cl, Br and cpa=carboxypentonic
acid) for which we made a theoretical prediction about the temperature
dependence of zero-field specific heat.


title: Cosmography of f(R) gravity

abstract:
  It is nowadays accepted that the universe is undergoing a phase of
accelerated expansion as tested by the Hubble diagram of Type Ia Supernovae
(SNeIa) and several LSS observations. Future SNeIa surveys and other probes
will make it possible to better characterize the dynamical state of the
universe renewing the interest in cosmography which allows a model independent
analysis of the distance - redshift relation. On the other hand, fourth order
theories of gravity, also referred to as $f(R)$ gravity, have attracted a lot
of interest since they could be able to explain the accelerated expansion
without any dark energy. We show here how it is possible to relate the
cosmographic parameters (namely the deceleration $q_0$, the jerk $j_0$, the
snap $s_0$ and the lerk $l_0$ parameters) to the present day values of $f(R)$
and its derivatives $f^{(n)}(R) = d^nf/dR^n$ (with $n = 1, 2, 3$) thus offering
a new tool to constrain such higher order models. Our analysis thus offers the
possibility to relate the model independent results coming from cosmography to
the theoretically motivated assumptions of $f(R)$ cosmology.


title: Magnetic cycles of the planet-hosting star tauBootis

abstract:
  We have obtained new spectropolarimetric observations of the planet-hosting
star tauBootis, using the ESPaDOnS and NARVAL spectropolarimeters at the
Canada-France-Hawaii Telescope and Telescope Bernard-Lyot. With this data set,
we are able to confirm the presence of a magnetic field at the surface of
tauBoo and map its large-scale structure over the whole star. The overall
polarity of the magnetic field has reversed with respect to our previous
observation (obtained a year before), strongly suggesting that tauBoo is
undergoing magnetic cycles similar to those of the Sun. This is the first time
that a global magnetic polarity switch is observed in a star other than the
Sun; we speculate that the magnetic cycle period of tauBoo is much shorter than
that of the Sun.
  Our new data also allow us to confirm the presence of differential rotation
from the latitudinal shearing that the magnetic structure is undergoing. The
differential rotation surface shear that tauBoo experiences is found to be 6 to
10 times larger than that of the Sun. We propose that the short magnetic cycle
period is due to the strong level of differential rotation. With a rotation
period of 3.0 and 3.9 d at the equator and pole respectively, tauBoo appears as
the first planet-hosting star whose rotation (at intermediate latitudes) is
synchronised with the orbital motion of its giant planet (period 3.3 d).
Assuming that this synchronisation is not coincidental, it suggests that the
tidal effects induced by the giant planet can be strong enough to force the
thin convective enveloppe (though not the whole star) into corotation and thus
to play a role in the activity cycle of tauBoo.


title: Experimental Realization of an Optical One-Way Barrier for Neutral Atoms

abstract:
  We demonstrate an asymmetric optical potential barrier for ultracold 87 Rb
atoms using laser light tuned near the D_2 optical transition. Such a one-way
barrier, where atoms impinging on one side are transmitted but reflected from
the other, is a realization of Maxwell's demon and has important implications
for cooling atoms and molecules not amenable to standard laser-cooling
techniques. In our experiment, atoms are confined to a far-detuned dipole trap
consisting of a single focused Gaussian beam, which is divided near the focus
by the barrier. The one-way barrier consists of two focused laser beams
oriented almost normal to the dipole-trap axis. The first beam is tuned to have
a red (blue) detuning from the F=1 -> F' (F=2 -> F') hyperfine transitions, and
thus presents a barrier only for atoms in the F=2 ground state, while letting
F=1 atoms pass. The second beam pumps the atoms to F=2 on the reflecting side
of the barrier, thus producing the asymmetry.


title: Program Promises

abstract:
  The framework of promise theory offers an alternative way of understanding
programming models, especially in distributed systems. We show that promise
theory can express some familiar constructs and resolve some problems in
program interface design, using fewer and simpler concepts than the Unified
Modelling Language (UML).


title: A Cluster of High Redshift Quasars with Apparent Diameter 2.3 Degrees

abstract:
  During analysis of the relation of quasars to galaxies in the 2dF deep field
a concentration of quasars was noted. Most striking was the closeness in
redshift of 14 quasars about the mean redshift z = 2.149 with a range of $\pm
0.018$. The cluster in spite of its high redshift subtends an area of diameter
more than 2.3 degrees on the sky. At conventional redshift distance its
diameter would be 181 mega parsecs and the back should be receding with about
$10,000 km/s$ with respect to the front.


title: Entanglement and Thermodynamics of Black Hole Entropy

abstract:
  Using simple conditions drawn from the stability of the cosmos in terms of
vacuum energy density, the cut-off momentum of entanglement is related to the
planckian mass. In so doing the black hole entropy is shown to be independent
of the number of field species that contribute to vacuum fluctuations. And this
is in spite of the fact that the number of field species is a linear
multiplicand of the entanglement entropy when this latter is expressed in terms
of the fundamental momentum cut-off of all fields.


title: Orbifold GUT model with nine Higgs doublets

abstract:
  We describe a non-supersymmetric orbifold GUT based on SU(5) symmetry. It is
a modification of Kawamura's 5-D orbifold GUT model. The difference lies in the
choice of Higgs scalars as we have allowed only 5-plets of SU(5) in the GUT
scale. This variant was originally proposed by Brahmachari and Raychoudhuri.
Proton decay problem and the doublet triplet splitting problems are solved by
extra dimensional mechanism. The unification scale is around $5.0 \times
10^{13}$ GeVs. In low energy there are nine Higgs doublets. One at the 100 GeV
region and eight others degenerate at around 1.4 TeV. It is an attractive
non-supersymmetric extension of standard model with very rich collider physics
phenomenology.


title: Poisson Hopf algebras associated to quantized enveloping algebras

abstract:
  We study certain Poisson structures related to quantized enveloping algebras.
In particular, we give a description of the Poisson structure of a certain
manifold associated to the ring of differential operators.


title: Strongly nondegenerate Lie algebras

abstract:
  Let $A$ be a semiprime 2 and 3-torsion free non-commutative associative
algebra. We show that the Lie algebra $\der(A)$ of (associative) derivations of
$A$ is strongly non-degenerate, which is a strong form of semiprimeness for Lie
algebras, under some additional restrictions on the center of $A$. This result
follows from a description of the quadratic annihilator of a general Lie
algebra inside appropriate Lie overalgebras. Similar results are obtained for
an associative algebra $A$ with involution and the Lie algebra $\sder(A)$ of
involution preserving derivations of $A$.


title: Quantum pattern recognition with liquid-state nuclear magnetic resonance

abstract:
  A novel quantum pattern recognition scheme is presented, which combines the
idea of a classic Hopfield neural network with adiabatic quantum computation.
Both the input and the memorized patterns are represented by means of the
problem Hamiltonian. In contrast to classic neural networks, the algorithm can
return a quantum superposition of multiple recognized patterns. A proof of
principle for the algorithm for two qubits is provided using a liquid state NMR
quantum computer.


title: A transference method in quantum probability

abstract:
  Working with a rather general notion of independence, we provide a
transference method which allows to compare the p-norm of sums of independent
copies with the p-norm of sums of free copies. Our main technique is to
construct explicit operator space Lp embeddings preserving independence to
reduce the problem to L1, where some recent results by the first-named author
can be used. We find applications for noncommutative Khincthine/Rosenthal type
inequalities and for noncommutative Lp embedding theory.


title: Local Analysis of Nonlinear Oscillations of Thin Accretion Disks

abstract:
  We calculated the coupling coefficients for non-linear, quasi-local
oscillatory modes of thin accretion disks. We found that several of them are
non-zero. Mode coupling is a necessary condition for a resonance, and thus our
results may be relevant for the recently discussed QPO resonance model.


title:
Giant orbital moments are responsible for the anisotropic
  magnetoresistance of atomic contacts

abstract:
  We study here, both experimentally and theoretically, the anisotropy of
magnetoresistance in atomic contacts. Our measurements on iron break junctions
reveal an abrupt and hysteretic switch between two conductance levels when a
large applied field is continuously rotated. We show that this behaviour stems
from the coexistence of two metastable electronic states which result from the
anisotropy of electronic interactions responsible for the enhancement of
orbital magnetization. In both states giant orbital moments appear on the low
coordinated central atom in a realistic contact geometry. However they differ
by their orientation, parallel or perpendicular, with respect to the axis of
the contact. Our explanation is totally at variance with the usual model based
on the band structure of a monatomic linear chain, which we argue cannot be
applied to 3d ferromagnetic metals.


title:
Coherence Conservation of a Qubit Coupled to a Thermal Dissipating
  Environment

abstract:
  It is shown that quantum coherence is conserved in a principal system in the
case that the system is coupled to a fast dissipating environment
[arXiv:0709.0562]. The phenomenon is called the quantum wipe effect. Here, this
effect is reviewed and the analytical proof for a model system consisting of a
one-qubit system coupled to a fast dissipating environment is extended to an
environment at a thermal equilibrium.


title:
Partial Regularity for Stationary Solutions to Liouville-Type Equation
  in dimension 3

abstract:
  In dimension $n=3$, we prove that the singular set of any stationary solution
to the Liouville equation $-\Delta u=e^u$, which belongs to $W^{1,2}$, has
Hausdorff dimension at most 1.


title:
Electronic transport in iron atomic contacts: from the infinite wire to
  realistic geometries

abstract:
  We present a theoretical study of spin polarized transport in Fe atomic
contacts using a self-consistent tight-binding Hamiltonian in a non-orthogonal
$s$, $p$ and $d$ basis set, the spin-polarization being obtained from a
non-collinear Stoner-like model and the transmission probability from the
Fisher-Lee formula. The behaviour of an infinite perfect Fe wire is compared
with that of an infinite chain presenting geometric defects or magnetic walls
and with that of a finite chain connected to infinite one-dimensional or
three-dimensional leads. In the presence of defects or contacts the
transmission probability of $d$ electrons is much more affected than that of
$s$ electrons, in particular, contact effects may suppress some transmission
channels. It is shown that the behaviour of an infinite wire is never obtained
even in the limit of long chains connected to electrodes. The introduction of
the spin-orbit coupling term in the Hamiltonian enables us to calculate the
anisotropy of the magneto-resistance. Finally whereas the variation of the
magneto-resistance as a function of the magnetization direction is step-like
for an infinite wire, it becomes smooth in the presence of defects or contacts.


title:
Newton's second law versus modified-inertia MOND: a test using the
  high-latitude effect

abstract:
  The modified-inertia MOND is an approach that proposes a change in Newton's
second law at small accelerations as an alternative to dark matter. Recently it
was suggested that this approach can be tested in terrestrial laboratory
experiments. One way of doing the test is based on the Static High-Latitude
Equinox Modified Inertia (SHLEM) effect: around each equinox date, 2 spots
emerge on the Earth where static bodies experience spontaneous displacement due
to the violation of Newton's second law required by the modified-inertia MOND.
Here, a detailed theory of this effect is developed and estimates of the
magnitude of the signal due to the effect are obtained. The expected
displacement of a mirror in a gravitational wave interferometer is found to be
about 10^{-14} m. Some experimental aspects of the proposal are discussed.


title: Generation of hierarchically correlated multivariate symbolic sequences

abstract:
  We introduce an algorithm to generate multivariate series of symbols from a
finite alphabet with a given hierarchical structure of similarities. The target
hierarchical structure of similarities is arbitrary, for instance the one
obtained by some hierarchical clustering procedure as applied to an empirical
matrix of Hamming distances. The algorithm can be interpreted as the finite
alphabet equivalent of the recently introduced hierarchically nested factor
model (M. Tumminello et al. EPL 78 (3) 30006 (2007)). The algorithm is based on
a generating mechanism that is different from the one used in the mutation rate
approach. We apply the proposed methodology for investigating the relationship
between the bootstrap value associated with a node of a phylogeny and the
probability of finding that node in the true phylogeny.


title: Curvaton Decay into Baryons, anti-Baryons and Radiation

abstract:
  This paper calculates the amount of baryon/radiation isocurvature fluctuation
produced through the decay of a curvaton field. It is shown in particular that
if curvaton decay preserves baryon number and the curvaton dominates the energy
density at the time of decay, the initial curvaton/radiation isocurvature mode
is entirely transfered into a baryon/radiation isocurvature mode. This
situation is opposite to that previously studied in three fluid models of
curvaton decay; this difference is related to the conservation of the
pre-existing baryon asymmetry and to the efficiency of the annihilation of all
baryon/anti-baryon pairs produced in the decay. We study in detail the relevant
cases in which the curvaton decay preserves or not baryon number and provide
analytical and numerical calculations for each situation.


title:
Chiral SU(3) Bethe Salpeter Model: Extension to SU(6) and SU(8)
  Spin-Flavor Symmetries

abstract:
  Consistent SU(6) and SU(8) spin-flavor extensions of the SU(3) flavor
Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian are constructed, which
incorporate vector meson degrees of freedom. In the charmless sector, the
on-shell approximation to the Bethe-Salpeter (BS) approach successfully
reproduces previous SU(3) WT results for the lowest-lying s--wave negative
parity baryon resonances. It also provides some information on the dynamics of
heavier ones and of the lightest d-wave negative parity resonances, as e.g. the
Lambda(1520). For charmed baryons the scheme is consistent with heavy quark
symmetry, and our preliminary results in the strangeness-less charm C=+1 sector
describe the main features of the three-star J^P=1/2^- Lambda_c(2595) and
J^P=3/2^- Lambda_c(2625) resonances. We also find a second broad J^P=1/2^-
state close to the Lambda_c(2595)


title:
Helioseismology of Sunspots: Confronting Observations with
  Three-Dimensional MHD Simulations of Wave Propagation

abstract:
  The propagation of solar waves through the sunspot of AR 9787 is observed
using temporal cross-correlations of SOHO/MDI Dopplergrams. We then use
three-dimensional MHD numerical simulations to compute the propagation of wave
packets through self-similar magneto-hydrostatic sunspot models. The
simulations are set up in such a way as to allow a comparison with observed
cross-covariances (except in the immediate vicinity of the sunspot). We find
that the simulation and the f-mode observations are in good agreement when the
model sunspot has a peak field strength of 3 kG at the photosphere, less so for
lower field strengths. Constraining the sunspot model with helioseismology is
only possible because the direct effect of the magnetic field on the waves has
been fully taken into account. Our work shows that the full-waveform modeling
of sunspots is feasible.


title: On the Complexity of Nash Equilibria of Action-Graph Games

abstract:
  We consider the problem of computing Nash Equilibria of action-graph games
(AGGs). AGGs, introduced by Bhat and Leyton-Brown, is a succinct representation
of games that encapsulates both "local" dependencies as in graphical games, and
partial indifference to other agents' identities as in anonymous games, which
occur in many natural settings. This is achieved by specifying a graph on the
set of actions, so that the payoff of an agent for selecting a strategy depends
only on the number of agents playing each of the neighboring strategies in the
action graph. We present a Polynomial Time Approximation Scheme for computing
mixed Nash equilibria of AGGs with constant treewidth and a constant number of
agent types (and an arbitrary number of strategies), together with hardness
results for the cases when either the treewidth or the number of agent types is
unconstrained. In particular, we show that even if the action graph is a tree,
but the number of agent-types is unconstrained, it is NP-complete to decide the
existence of a pure-strategy Nash equilibrium and PPAD-complete to compute a
mixed Nash equilibrium (even an approximate one); similarly for symmetric AGGs
(all agents belong to a single type), if we allow arbitrary treewidth. These
hardness results suggest that, in some sense, our PTAS is as strong of a
positive result as one can expect.


title: A semi-classical inverse problem I: Taylor expansions

abstract:
  In dimension 1, we show that the Taylor expansion of a potential near a
generic non degenerate critical point can be recovered from the knowledge of
the semi-classical spectrum of the associated Schr\"odinger operator near the
corresponding critical value.


title: The old and the new of parity-violating two-pion-exchange $NN$ potential

abstract:
  We consider the parity-violating two-pion-exchange potential obtained from
the covariant formalism in the past and the state-of-the-art effective field
theory approach. We discuss the behavior of the potential in coordinate space
and its application to the parity-violating asymmetry in $\vec{n} p \to d
\gamma$ at threshold.


title:
Properties of the density for a three dimensional stochastic wave
  equation

abstract:
  We consider a stochastic wave equation in space dimension three driven by a
noise white in time and with an absolutely continuous correlation measure given
by the product of a smooth function and a Riesz kernel. Let $p_{t,x}(y)$ be the
density of the law of the solution $u(t,x)$ of such an equation at points
$(t,x)\in]0,T]\times \IR^3$. We prove that the mapping $(t,x)\mapsto
p_{t,x}(y)$ owns the same regularity as the sample paths of the process
$\{u(t,x), (t,x)\in]0,T]\times \mathbbR^3\}$ established Dalang and Sanz-Sol\'e
[Memoirs of the AMS, to appear]. The proof relies on Malliavin calculus and
more explicitely, Watanabe's integration by parts formula and estimates derived
form it.


title: Hardy's Uncertainty Principle, Convexity and Schr\"odinger Evolutions

abstract:
  We prove the logarithmic convexity of certain quantities, which measure the
quadratic exponential decay at infinity and within two characteristic
hyperplanes of solutions of Schr\"odinger evolutions. As a consequence we
obtain some uniqueness results that generalize (a weak form of) Hardy's version
of the uncertainty principle. We also obtain corresponding results for heat
evolutions.


title: Symmetric construction of reference-frame-free qudits

abstract:
  By exploiting a symmetric scheme for coupling $N$ spin-1/2 constituents (the
physical qubits) to states with total angular momentum $N/2-1$, we construct
rotationally invariant logical qudits of dimension $d=N-1$. One can encode all
qudit states, and realize all qudit measurements, by this construction. The
rotational invariance of all relevant objects enables one to transmit quantum
information without having aligned reference frames between the parties that
exchange the qudits. We illustrate the method by explicit constructions of
reference-frame-free qubits and qutrits and, for the qubit case, comment on
possible experimental implementations.


title:
Controlling soliton excitations in Heisenberg spin chain through magic
  angle

abstract:
  We study the nonlinear dynamics of collective excitation in a $N$-site $XXZ$
quantum spin chain, which is manipulated by an oblique magnetic field. We show
that, when the tilted field is applied along the magic angle $\theta_{0}
=\pm\arccos \sqrt{1/3}$, the anisotropic Heisenberg spin chain becomes
isotropic and thus an free propagating spin wave is stimulated. And in the
regime of the tilted angle larger and smaller then the magic angle, two types
of nonlinear excitations appear, which are bright soliton and dark soliton.


title: Converging sequences in the ab initio no-core shell model

abstract:
  We demonstrate the existence of multiple converging sequences in the ab
initio no-core shell model. By examining the underlying theory of effective
operators, we expose the physical foundations for the alternative pathways to
convergence. This leads us to propose a revised strategy for evaluating
effective interactions for $A$-body calculations in restricted model spaces. We
suggest that this strategy is particularly useful for applications to nuclear
processes in which states of both parities are used simultaneously, such as for
transition rates. We demonstrate the utility of our strategy with large-scale
calculations in light nuclei.


title: Discrete Riemann Surfaces

abstract:
  We detail the theory of Discrete Riemann Surfaces. It takes place on a
cellular decomposition of a surface, together with its Poincar\'e dual,
equipped with a discrete conformal structure. A lot of theorems of the
continuous theory follow through to the discrete case, we define the discrete
analogs of period matrices, Riemann's bilinear relations, exponential of
constant argument and series. We present the notion of criticality and its
relationship with integrability.


title: Charm mesons at FAIR

abstract:
  The in-medium properties of charm mesons ($D$ and $\bar D$) in a hot and
dense matter are studied. A self-consistent coupled-channel approach is driven
by a broken SU(4) s-wave Tomozawa-Weinberg interaction supplemented by an
attractive isoscalar-scalar term. As medium effects, we include Pauli blocking,
baryon mean-field bindings, and $\pi$ and open-charm meson self-energies. The
dynamically generated $\tilde\Lambda_c$ and $\tilde\Sigma_c$ resonances in the
$DN$ sector remain close to their free space position but acquire large widths.
The resultant $D$ meson spectral function, which shows a single pronounced
quasiparticle peak close to the free mass that broadens with increasing
density, also has a long low energy tail associated with smeared
$\tilde\Lambda_c N^{-1}$, $\tilde\Sigma_c N^{-1}$ configurations. The
low-density approximation for the $\bar D N$ is questionable already at
subsaturation densities. We touch upon the implication of our study for
$J/\Psi$ suppression at FAIR.


title: Detecting solar g-modes with ASTROD

abstract:
  We present an up-to-date estimate for the prospect of using the
Astrodynamical Space Test of Relativity using Optical Devices (ASTROD) for an
unambiguous detection of solar g modes (f < 400 micro Hertz) through their
gravitational signature. There are currently two major efforts to detect
low-frequency gravitational effects, ASTROD and the Laser Interferometer Space
Antenna (LISA). Using the most recent g mode surface amplitude estimates, both
observational and theoretical, it is unclear whether LISA will be capable of
successfully detecting these modes. The ASTROD project may be better suited for
detection as its sensitivity curve is shifted towards lower frequencies with
the best sensitivity occurring in the range 100-300 micro Hertz.


title: Real-Time Data Driven Wildland Fire Modeling

abstract:
  We are developing a wildland fire model based on semi-empirical relations
that estimate the rate of spread of a surface fire and post-frontal heat
release, coupled with WRF, the Weather Research and Forecasting atmospheric
model. A level set method identifies the fire front. Data are assimilated using
both amplitude and position corrections using a morphing ensemble Kalman
filter. We will use thermal images of a fire for observations that will be
compared to synthetic image based on the model state.


title: The wave equation on static singular space-times

abstract:
  The first part of my thesis lays the foundations to generalized Lorentz
geometry. The basic algebraic structure of finite-dimensional modules over the
ring of generalized numbers is investigated. The motivation for this part of my
thesis evolved from the main topic, the wave equation on singular space-times.
The second and main part of my thesis is devoted to establishing a local
existence and uniqueness theorem for the wave equation on singular space-times.
The singular Lorentz metric subject to our discussion is modeled within the
special algebra on manifolds in the sense of Colombeau. Inspired by an approach
to generalized hyperbolicity of conical-space times due to Vickers and Wilson,
we succeed in establishing certain energy estimates, which by a further
elaborated equivalence of energy integrals and Sobolev norms allow us to prove
existence and uniqueness of local generalized solutions of the wave equation
with respect to a wide class of generalized metrics. The third part of my
thesis treats three different point value resp. uniqueness questions in
algebras of generalized functions


title: Discrete Complex Structure on Surfel Surfaces

abstract:
  This paper defines a theory of conformal parametrization of digital surfaces
made of surfels equipped with a normal vector. The main idea is to locally
project each surfel to the tangent plane, therefore deforming its aspect-ratio.
It is a generalization of the theory known for polyhedral surfaces. The main
difference is that the conformal ratios that appear are no longer real in
general. It yields a generalization of the standard Laplacian on weighted
graphs.


title:
Coupling of Electronic and Motional Dynamics in a Cold Atom Optical
  Lattice

abstract:
  We study the coupling of internal electronic excitations to vibrational modes
of the external motion of ultracold atoms in an optical lattice. For different
ground and excited state potentials the on-site coupling of excitations and
vibrations term renormalizes the effective electronic transition energy, which
appears e.g. in clock transitions. In addition in the Mott state with filling
factor one, the dipole-dipole coupling between neighbouring sites includes
emission and absorption of vibrational quanta. Such processes create a
significant mechanism for excitation of vibrations leading to motional heating
of the lattice atoms by resonant light interaction. We calculate estimates of
the corresponding parameters from a perturbation expansion in small atomic
displacements.


title:
A valuation criterion for normal basis generators in local fields of
  characteristic $p$

abstract:
  Let $K$ be a complete local field of characteristic $p$ with perfect residue
field. Let $L/K$ be a finite, fully ramified, Galois $p$-extension. If
$\pi_L\in L$ is a prime element, and $p'(x)$ is the derivative of $\pi_L$'s
minimal polynomial over $K$, then the relative different $\euD_{L/K}$ is
generated by $p'(\pi_L)\in L$. Let $v_L$ be the normalized valuation normalized
with $v_L(L)=\mathbb{Z}$. We show that any element $\rho\in L$ with
$v_L(\rho)\equiv -v_L(p'(\pi_L))-1\bmod[L:K]$ generates a normal basis,
$K[{Gal}(L/K)]\cdot\rho=L$. This criterion is tight: Given any integer $i$ such
that $i\not\equiv -v_L(p'(\pi_L))-1\bmod[L:K]$, there is a $\rho_i\in L$ with
$v_L(\rho_i)=i$ such that $K[{Gal}(L/K)]\cdot\rho_i\subsetneq L$.


title: Evacuation Dynamics: Empirical Results, Modeling and Applications

abstract:
  This extensive review was written for the ``Encyclopedia of Complexity and
System Science'' (Springer, 2008) and addresses a broad audience ranging from
engineers to applied mathematicians, computer scientists and physicists. It
provides an extensive overview of various aspects of pedestrian dynamics,
focussing on evacuation processes. First the current status of empirical
results is critically reviewed as it forms the basis for the calibration of
models needed for quantitative predictions. Then various modeling approaches
are discussed, focussing on cellular automata models. Finally, some specific
applications to safety analysis in public buildings or public transport are
presented.


title:
Washington CCD Photometry of the Globular Cluster System of the Giant
  Elliptical Galaxy M60 in Virgo

abstract:
  We present a photometric study of the globular clusters in the giant
elliptical galaxy M60 in the Virgo cluster, based on deep, relatively wide
field Washington CT_1 CCD images. The color-magnitude diagram reveals a
significant population of globular clusters in M60, and a large number of young
luminous clusters in NGC 4647, a small companion spiral galaxy north-west of
M60. The color distribution of the globular clusters in M60 is clearly bimodal,
with a blue peak at (C-T_1)=1.37, and a red peak at (C-T_1)=1.87. We derive two
new transformation relations between the (C-T_1)_0 color and [Fe/H] using the
data for the globular clusters in our Galaxy and M49. Using these relations we
derive the metallicity distribution of the globular clusters in M60, which is
also bimodal: a dominant metal-poor component with center at [Fe/H]=-1.2, and a
weaker metal-rich component with center at [Fe/H]=-0.2. The radial number
density profile of the globular clusters is more extended than that of the
stellar halo, and the radial number density profile of the blue globular
clusters is more extended than that of the red globular clusters. The number
density maps of the globular clusters show that the spatial distribution of the
blue globular clusters is roughly circular, while that of the red globular
cluster is elongated similarly to that of the stellar halo. We estimate the
total number of the globular clusters in M60 to be 3600+/-500$,and the specific
frequency to be S_N=3.8+/-0.4. The mean color of the bright blue globular
clusters gets redder as they get brighter in both the inner and outer region of
M60. This blue tilt is seen also in the outer region of M49, the brightest
Virgo galaxy. Implications of these results are discussed.


title:
HI content and other structural properties of galaxies in the Virgo
  cluster from the Arecibo Legacy Fast ALFA Survey

abstract:
  We report the results of an HI blind survey of 80deg^2 of the Virgo cluster,
based on the 08deg < delta < 16 deg strip of ALFALFA, the Arecibo Legacy Fast
ALFA Survey. 187 HI sources of high significance are found providing a complete
census of HI sources in this region of the Virgo cluster (-1000<cz<3000 km/s)
with M_HI > 10^7.5-8 M_sun. 156/187 (83%) sources are identified with optical
galaxies from the Virgo Cluster Catalogue (Binggeli et al. 1985), all but 8
with late-type galaxies. Ten sources are not associated with optical galaxies
and were found to correspond to tidally-disrupted systems (see Kent et al. 2007
and Haynes, Giovanelli and Kent 2007). The remaining 21 (11%) are associated
with galaxies that are not listed in the Virgo Cluster Catalogue. For all
sources with an optical counterpart in the Sloan Digital Sky Survey, we
analyzed i-band SDSS plates to measure optical structural parameters. We find
that in the Virgo cluster: i) HI inhabits galaxies that are structurally
similar to ordinary late-type galaxies; ii) their HI content can be predicted
from their optical luminosity; iii) low surface brightness galaxies have low
optical luminosity and contain small quantities of neutral hydrogen; iv) low
surface brightness, massive Malin1 type galaxies are comfortably rare objects
(less than 0.5%); v) there are no "dark-galaxies" with HI masses M_HI >
10^7.5-8 M_sun; vi) less than 1% of early-type galaxies contain neutral
hydrogen with M_HI>10^7.5-8 M_sun (di Serego Alighieri et al. 2007).


title:
EMC effect with different oscillator-model parameters $h\omega$ for
  different shells by considering difference between proton and neutron
  structure functions

abstract:
  The magnitude of binding energy used in the conventional nuclear theory to
explain the EMC experimental data, seems to be larger than the one expected. In
this paper to get sufficient depletion in the binding energy, different
oscillator-model parameters $ \textit{$h\omega$} $ for different shells and the
proton (neutron) structure function that have good agrement with experimental
data are used. The extracted results for $^4He, ^{12}C, ^{40}Ca$ and $^{56}Fe$
nuclei show that one can get improved results in medium x ranges by less
binding energy.


title: Triangle-generation in topological D-brane categories

abstract:
  Tachyon condensation in topological Landau-Ginzburg models can generally be
studied using methods of commutative algebra and properties of triangulated
categories. The efficiency of this approach is demonstrated by explicitly
proving that every D-brane system in all minimal models of type ADE can be
generated from only one or two fundamental branes.


title: Constructing a counterexample to the black hole complementarity

abstract:
  We propose a regular black hole whose inside generates a de Sitter space and
then is finally frustrated into a singularity. It is a modified model which was
suggested originally by Frolov, Markov, and Mukhanov. In our model, we could
adjust a regular black hole so that its period before going into the extreme
state is much longer than the information retention time. During this period an
observer could exist who observes the information of the Hawking radiation,
falls freely into the regular center of the black hole, and finally meets the
free-falling information again. The existence of such an observer implies that
the complementary view may not be consistent with a regular black hole, and
therefore, is not appropriate as a generic principle of black hole physics.


title: A special class of holomorphic mappings and the Faddeev-Hopf model

abstract:
  Pseudo horizontally weakly conformal maps extend both holomorphic and
(semi)conformal maps into an almost Hermitian manifold. We find in this larger
class critical points for the (generalized) Faddeev-Hopf energy. Their
stability is also discussed in some cases.


title: Neutrino induced weak pion production off the nucleon

abstract:
  We study neutrino induced one-pion production off the nucleon in and around
the Delta resonance region. Apart from the Delta-pole mechanism we include
background terms required by chiral symmetry. These background terms give
sizeable contributions in all channels. To better reproduce the ANL
$q^2$-differential cross section data, we make a new fit of the $C_5^A(q^2)$
axial nucleon to Delta form factor. The new result $C_5^A(0)=0.867\pm 0.075$ is
some 30% smaller than the commonly accepted value.
  This correction is compatible with most quark model estimates and a recent
lattice calculation


title: The Dynamics of Subhalos in Warm Dark Matter Models

abstract:
  We present a comparison of the properties of substructure halos (subhalos)
orbiting within host halos that form in Cold Dark Matter (CDM) and Warm Dark
Matter (WDM) cosmologies. Our study focuses on selected properties of these
subhalos, namely their anisotropic spatial distribution within the hosts; the
existence of a "backsplash'' population; the age-distance relation; the degree
to which they suffer mass loss; and the distribution of relative (infall)
velocities with respect to the hosts. We find that the number density of
subhalos in our WDM model is suppressed relative to that in the CDM model, as
we would expect. Interestingly, our analysis reveals that backsplash subhalos
exist in both the WDM and CDM models. Indeed, there are no statistically
significant differences between the spatial distributions of subhalos in the
CDM and WDM models. There is evidence that subhalos in the WDM model suffer
enhanced mass loss relative to their counterparts in the CDM model, reflecting
their lower central densities. We note also a tendency for the (infall)
velocities of subhalos in the WDM model to be higher than in the CDM model.
Nevertheless, we conclude that observational tests based on either the spatial
distribution or the kinematics of the subhalo population are unlikely to help
us to differentiate between the CDM model and our adopted WDM model.


title:
Metal-Insulator Transition in 2D: Experimental Test of the Two-Parameter
  Scaling

abstract:
  We report a detailed scaling analysis of resistivity \rho(T,n) measured for
several high-mobility 2D electron systems in the vicinity of the 2D
metal-insulator transition. We analyzed the data using the two parameter
scaling approach and general scaling ideas. This enables us to determine the
critical electron density, two critical indices, and temperature dependence for
the separatrix in the self-consistent manner. In addition, we reconstruct the
empirical scaling function describing a two-parameter surface which fits well
the \rho(T,n) data.


title: Strong coupling between a metallic nanoparticle and a single molecule

abstract:
  We theoretically investigate strong coupling between a single molecule and a
single metallic nanoparticle. A theory suited for the quantum-mechanical
description of surface plasmon polaritons (SPPs) is developed. The coupling
between these SPPs and a single molecule, and the modified molecular dynamics
in presence of the nanoparticle are described within a combined Drude and
boundary-element-method approach. Our results show that strong coupling is
possible for single molecules and metallic nanoparticles, and can be observed
in fluorescence spectroscopy through the splitting of emission peaks.


title:
Comment on "Correlation between Dynamic Heterogeneity and Medium-Range
  Order in Two-Dimensional Glass-Forming Liquids"

abstract:
  In a recent letter, Kawasaki et al. (PRL 99, 215701 (2007)) study glass
formation in a 2-dimensional (2D) model of polydisperse repulsive disks. They
give numerical evidence for a direct relation between slowing down of the
relaxation, extension of some medium-range order, and development of dynamic
heterogeneities. We disagree with the authors' interpretation on two points
which we believe to be potentially important for understanding the glass
transition.


title: Nonlocal Particles as Strings

abstract:
  We find nonlocal particle theories with two dimensional conformal symmetry,
including examples equivalent to the bosonic open string and closed string.
This work provides a new approach to construct solvable consistent backgrounds
in string theory.


title: Note on genuine multipartite classical correlations

abstract:
  We discuss the problem of coexistence of genuine quantum multipartite
correlations and classical multipartite correlations. We introduce a postulate
which any measure of genuine multipartite classical correlations should
satisfy. We show that covariance does not satisfy this postulate. Finally we
propose a definition of genuine multipartite correlations and illustrate it
with examples.


title: Bouncing Cosmologies

abstract:
  We review the general features of nonsingular universes ({\em i.e.} those
that go from an era of accelerated collapse to an expanding era without
displaying a singularity) as well as cyclic universes. We discuss the
mechanisms behind the bounce, and analyze examples of solutions that implement
these mechanisms. Observational consequences of such regular cosmologies are
also considered, with emphasis in the behavior of the perturbations.


title:
Observations of GRB 060526 Optical Afterglow with Russian-Turkish 1.5-m
  Telescope

abstract:
  We present the results of the photometric multicolor observations of GRB
060526 optical afterglow obtained with Russian-Turkish 1.5-m Telescope (RTT150,
Mt. Bakirlitepe, Turkey). The detailed measurements of afterglow light curve,
starting from about 5 hours after the GRB and during 5 consecutive nights were
done. In addition, upper limits on the fast variability of the afterglow during
the first night of observations were obtained and the history of afterglow
color variations was measured in detail. In the time interval from 6 to 16
hours after the burst, there is a gradual flux decay, which can be described
approximately as a power law with an index of -1.14+-0.02. After that the
variability on the time scale \delta t < t is observed and the afterglow
started to decay faster. The color of the afterglow, V-R=~0.5, is approximately
the same during all our observations. The variability is detected on time
scales up to \delta t/t =~ 0.0055 at \Delta F_\nu/F_\nu =~ 0.3, which violates
some constraints on the variability of the observed emission from
ultrarelativistic jet obtained by Ioka et al. (2005). We suggest to explain
this variability by the fact that the motion of the emitting shell is no longer
ultrarelativistic at this time.


title:
On the Variability of Gamma-Ray Burst Afterglows - A Possibility of a
  Transition to Nonrelativistic Motion

abstract:
  Variability on time scales \delta t < t is observed in many gamma-ray burst
afterglows. It is well known that there should be no such variability if the
afterglow is emitted by external shock, which is produced by the interaction of
ultrarelativistic ejecta with the ambient interstellar medium, within the
framework of simple models. The corresponding constraints were established by
Ioka et al. (2005) and in some cases are inconsistent with observations. On the
other hand, if the motion is not relativistic, then the fast variability of the
afterglow can be explained much more easily.
  In this connection we discuss various estimates of the time of the transition
to subrelativistic motion in GRB source. We point out, that this transition
should occur on an observed time scale of ~10 days. In the case of a higher
density of the ambient interstellar medium ~10^2-10^4 cm^{-3} or dense stellar
wind with \dot M ~ 10^{-5} - 10^{-4} M_\odot/year the transition to a
subrelativistic motion can occur on a time scale of ~1 day. These densities may
well be expected in star-forming regions and around massive Wolf-Rayet stars.


title: Asymptotic equivalence and contiguity of some random graphs

abstract:
  We show that asymptotic equivalence, in a strong form, holds between two
random graph models with slightly differing edge probabilities under
substantially weaker conditions than what might naively be expected.
  One application is a simple proof of a recent result by van den Esker, van
der Hofstad and Hooghiemstra on the equivalence between graph distances for
some random graph models.


title: Explicit eigenvalue estimates for transfer operators

abstract:
  We consider transfer operators acting on spaces of holomorphic functions, and
provide explicit bounds for their eigenvalues. More precisely, if D is any open
set in C^d, and L is a suitable transfer operator acting on Bergman space
A^2(D), its eigenvalue sequence lambda_n(L) is bounded by |lambda_n(L)| \leq
A\exp(-a n^{1/d}), where a, A are explicitly given.


title: Noise gates for decoherent quantum circuits

abstract:
  A major problem in exploiting microscopic systems for developing a new
technology based on the principles of Quantum Information is the influence of
noise which tends to work against the quantum features of such systems. It
becomes then crucial to understand how noise affects the evolution of quantum
circuits: several techniques have been proposed among which stochastic
differential equations (SDEs) can represent a very convenient tool. We show how
SDEs naturally map any Markovian noise into a linear operator, which we will
call a noise gate, acting on the wave function describing the state of the
circuit, and we will discuss some examples. We shall see that these gates can
be manipulated like any standard quantum gate, thus simplifying in certain
circumstances the task of computing the overall effect of the noise at each
stage of the protocol. This approach yields equivalent results to those derived
from the Lindblad equation; yet, as we show, it represents a handy and fast
tool for performing computations, and moreover, it allows for fast numerical
simulations and generalizations to non Markovian noise. In detail we review the
depolarizing channel and the generalized amplitude damping channel in terms of
this noise gate formalism and show how these techniques can be applied to any
quantum circuit.


title: Enumerative Geometry of Calabi-Yau 5-Folds

abstract:
  Gromov-Witten theory is used to define an enumerative geometry of curves in
Calabi-Yau 5-folds. We find recursions for meeting numbers of genus 0 curves,
and we determine the contributions of moving multiple covers of genus 0 curves
to the genus 1 Gromov-Witten invariants. The resulting invariants, conjectured
to be integral, are analogous to the previously defined BPS counts for
Calabi-Yau 3 and 4-folds. We comment on the situation in higher dimensions
where new issues arise.
  Two main examples are considered: the local Calabi-Yau P^2 with balanced
normal bundle 3O(-1) and the compact Calabi-Yau hypersurface X_7 in P^6. In the
former case, a closed form for our integer invariants has been conjectured by
G. Martin. In the latter case, we recover in low degrees the classical
enumeration of elliptic curves by Ellingsrud and Stromme.


title:
ALFALFA: The Search for (Almost) Dark Galaxies and their Space
  Distribution

abstract:
  The Arecibo Legacy Fast ALFA (ALFALFA) survey is designed to explore the z=0
HI mass function (HIMF) over a cosmologically significant volume. ALFALFA will
improve on previous determinations of the HIMF by its combination of depth,
wide area and centroiding accuracy, the latter allowing, in most cases,
immediate identification of the optical counterpart to each HI signal. ALFALFA
will detect hundreds of galaxies with HI masses less than 10**7.5 solar masses
and also greater than 10**10.5 solar masses, and its final catalog will allow
investigation of the dependence of the HIMF both on local density and on galaxy
morphology. Already ALFALFA confirms previous suggestions that there is no
cosmologically significant population of HI-rich dark galaxies. Fewer than 3%
of all extragalactic HI sources and < 1% of ones with HI masses > 10**9.5 solar
masses cannot be identified with a stellar counterpart. Very preliminary
results on the presence of gas-rich dwarfs in the void in front of the
Pisces-Perseus supercluster suggest an underabundance of such objects compared
to the predictions of numerical simulations. The objects with highest HI mass
exhibit a range of morphologies and optical colors and surface brightnesses but
all appear to be massive disk systems. The latter represent the population
likely to dominate future studies of HI at higher redshift with the Square
Kilometer Array.


title:
The time slice axiom in perturbative quantum field theory on globally
  hyperbolic spacetimes

abstract:
  The time slice axiom states that the observables which can be measured within
an arbitrarily small time interval suffice to predict all other observables.
While well known for free field theories where the validity of the time slice
axiom is an immediate consequence of the field equation it was not known
whether it also holds in generic interacting theories, the only exception being
certain superrenormalizable models in 2 dimensions. In this paper we prove that
the time slice axiom holds at least for scalar field theories within formal
renormalized perturbation theory.


title: A semi-classical inverse problem II: reconstruction of the potential

abstract:
  This paper is the continuation of our work with Victor Guillemin; Victor and
I proved that the Taylor expansion of the potential at a generic non degenerate
critical point is determined by the semi-classical spectrum of the associated
Schr\"odinger operator near the corresponding critical value. Here, I show
that, under some genericity assumptions, the potential of the 1D Schroedinger
operator is determined by its semi-classical spectrum. Moreover, there is an
explicit reconstruction. This paper is strongly related to a paper of David
Gurarie (J. Math. Phys. 36:1934--1944 (1995)).


title: On Limiting Distributions Of Estimation Of Central Moments

abstract: This paper has been withdrawn at the author's request.


title: On Jacobi Sums in $\mathbb Q(\zeta_p)$

abstract:
  We study the p-adic behavior of Jacobi Sums for $\mathbb Q(\zeta_p)$ and link
this study to the p-Sylow subgroup of the ideal class group of $\mathbb
Q(\zeta_p\`a^+$


title:
Detecting chaos, determining the dimensions of tori and predicting slow
  diffusion in Fermi--Pasta--Ulam lattices by the Generalized Alignment Index
  method

abstract:
  The recently introduced GALI method is used for rapidly detecting chaos,
determining the dimensionality of regular motion and predicting slow diffusion
in multi--dimensional Hamiltonian systems. We propose an efficient computation
of the GALI$_k$ indices, which represent volume elements of $k$ randomly chosen
deviation vectors from a given orbit, based on the Singular Value Decomposition
(SVD) algorithm. We obtain theoretically and verify numerically asymptotic
estimates of GALIs long--time behavior in the case of regular orbits lying on
low--dimensional tori. The GALI$_k$ indices are applied to rapidly detect
chaotic oscillations, identify low--dimensional tori of Fermi--Pasta--Ulam
(FPU) lattices at low energies and predict weak diffusion away from
quasiperiodic motion, long before it is actually observed in the oscillations.


title: Classical and quantum integrability

abstract: We give a sufficient condition for quantising integrable systems.


title:
On the contact conditions for the charge profile in the theory of the
  electrical double layer for nonsymmetrical electrolytes

abstract:
  The contact value of the charge profile for nonsymmetrical electrolytes is
presented as the sum of three contributions. One of them is the normal
component of the Maxwell electrostatic stress tensor. The second one is the
surface electrostatic property defined as the integral of the product of the
gradient of the electrical potential and the density distribution function of
coions. The third term is the bulk contribution defined by the sum for anions
and for cations of the product of their charge and their partial pressure. For
noncharged surfaces only the last two are present and have the same sign in the
case of size asymmetry. In the case of charge asymmetry the contact value of
the charge profile is the result of the competitions of bulk and surface terms
in which the bulk term is dominant. Using both the contact theorems for the
density and the charge profiles, the exact expressions for the contact values
of the profiles of coions and counterions are obtained and some related
properties are discussed.


title:
Multiple Component Analysis of Time Resolved Spectra of GRB041006: A
  Clue to the Nature of Underlying Soft Component of GRBs

abstract:
  GRB 041006 was detected by HETE-2 at 12:18:08 UT on 06 October 2004. This GRB
displays a soft X-ray emission, a precursor before the onset of the main event,
and also a soft X-ray tail after the end of the main peak. The light curves in
four different energy bands display different features; At higher energy bands
several peaks are seen in the light curve, while at lower energy bands a single
broader bump dominates. It is expected that these different features are the
result of a mixture of several components each of which has different
energetics and variability. To reveal the nature of each component, we analysed
the time resolved spectra and they are successfully resolved into several
components. We also found that these components can be classified into two
distinct classes; One is a component which has an exponential decay of $E_{p}$
with a characteristic timescale shorter than $\sim$ 30 sec, and its spectrum is
well represented by a broken power law function, which is frequently observed
in many prompt GRB emissions, so it should have an internal-shock origin.
Another is a component whose $E_{p}$ is almost unchanged with characteristic
timescale longer than $\sim$ 60 sec, and shows a very soft emission and slower
variability. The spectrum of the soft component is characterized by either a
broken power law or a black body spectrum. This component might originate from
a relatively wider and lower velocity jet or a photosphere of the fireball. By
assuming that the soft component is a thermal emission, the radiation radius is
initially $4.4 \times 10^{6}$ km, which is a typical radius of a blue
supergiant, and its expansion velocity is $2.4 \times 10^{5}$ km/s in the
source frame.


title: Detection of GRB signals with Fluorescence Detectors

abstract:
  Gamma Ray Bursts are being searched in many ground based experiments
detecting the high energy component (GeV $\div$ TeV energy range) of the photon
bursts. In this paper, Fluorescence Detectors are considered as possible
candidate devices for these searches. It is shown that the GRB photons induce
fluorescence emission of UV photons on a wide range of their spectrum. The
induced fluorescence flux is dominated by GRB photons from 0.1 to about 100 MeV
and, once the extinction through the atmosphere is taken into account, it is
distributed over a wide angular region. This flux can be detected through a
monitor of the diffuse photon flux, provided that its maximum value exceeds a
threshold value, that is primarily determined by the sky brightness above the
detector. The feasibility of this search and the expected rates are discussed
on the basis of the current GRB observations and the existing fluorescence
detectors.


title: Mirabolic Robinson-Schensted-Knuth correspondence

abstract:
  The set of orbits of $GL(V)$ in $Fl(V)\times Fl(V)\times V$ is finite, and is
parametrized by the set of certain decorated permutations in a work of Solomon.
We describe a Mirabolic RSK correspondence (bijective) between this set of
decorated permutations and the set of triples: a pair of standard Young
tableaux, and an extra partition. It gives rise to a partition of the set of
orbits into combinatorial cells. We prove that the same partition is given by
the type of a general conormal vector to an orbit. We conjecture that the same
partition is given by the bimodule Kazhdan-Lusztig cells in the bimodule over
the Iwahori-Hecke algebra of $GL(V)$ arising from $Fl(V)\times Fl(V)\times V$.
We also give conjectural applications to the classification of unipotent
mirabolic character sheaves on $GL(V)\times V$.


title: Mirabolic affine Grassmannian and character sheaves

abstract:
  We compute the Frobenius trace functions of mirabolic character sheaves
defined over a finite field. The answer is given in terms of the character
values of general linear groups over the finite field, and the structure
constants of multiplication in the mirabolic Hall-Littlewood basis of symmetric
functions, introduced by Shoji.


title: Stability of discrete dark solitons in nonlinear Schrodinger lattices

abstract:
  We obtain new results on the stability of discrete dark solitons bifurcating
from the anti-continuum limit of the discrete nonlinear Schrodinger equation,
following the analysis of our previous paper [Physica D 212, 1-19 (2005)]. We
derive a criterion for stability or instability of dark solitons from the
limiting configuration of the discrete dark soliton and confirm this criterion
numerically. We also develop detailed calculations of the relevant eigenvalues
for a number of prototypical configurations and obtain very good agreement of
asymptotic predictions with the numerical data.


title: Maximal monotonicity, conjugation and the duality product

abstract:
  Recently, the authors studied the connection between each maximal monotone
operator T and a family H(T) of convex functions. Each member of this family
characterizes the operator and satisfies two particular inequalities.
  The aim of this paper is to establish the converse of the latter fact.
Namely, that every convex function satisfying those two particular inequalities
is associated to a unique maximal monotone operator.


title: Single-Pole Interaction of the Particle with the String

abstract:
  Within the framework of generalized Papapetrou method, we derive the
effective equations of motion for a string with two particles attached to its
ends, along with appropriate boundary conditions. The equations of motion are
the usual Nambu-Goto-like equations, while boundary conditions turn out to be
equations of motion for the particles at the string ends. Various properties of
those equations are discussed, and a simple example is treated in detail,
exhibiting the properties of Neumann and Dirichlet boundary conditions and
giving a small correction term to the law of Regge trajectories due to the
nonzero particle mass.


title:
Resummation of projectile-target multiple scatterings and parton
  saturation

abstract:
  In the framework of a toy model which possesses the main features of QCD in
the high energy limit, we conduct a numerical study of scattering amplitudes
constructed from parton splittings and projectile-target multiple interactions,
in a way that unitarizes the amplitudes without however explicit saturation in
the wavefunction of the incoming states. This calculation is performed in two
different ways. One of these formulations, the closest to field theory,
involves the numerical resummation of a factorially divergent series, for which
we develop appropriate numerical tools. We accurately compare the properties of
the resulting amplitudes with what would be expected if saturation were
explicitly included in the evolution of the states. We observe that the
amplitudes have similar properties in a small but finite range of rapidity in
the beginning of the evolution, as expected. Some of the features of
reaction-diffusion processes are already present in that range, even when
saturation is left out of the model.


title:
On the low frequency electromagnetic waves in quasi-two-dimensional
  metals

abstract:
  Here, we theoretically analyze spectra of weakly attenuated electromagnetic
waves which may appear in a Fermi-liquid of charge carriers in
quasi-two-dimensional (Q2D) layered conductors when an external magnetic field
is applied perpendicularly to the conducting layers. We study transverse modes
propagating along the magnetic field. The frequencies of the modes are assumed
to be lower than the cyclotron frequency of the charge carriers. It is shown
that Fermi-liquid interaction of the charge carriers in Q2D conductors gives
rise to a mode which cannot appear in a gase of charged quasiparticles, as well
as it happens in conventional metals. Also, we show that the Fermi surface
plofile may cause significant changes in the waves spectra and we analyze these
changes.


title: Branes in hearts with perverse sheaves

abstract:
  Various topological properties of D-branes in the type--IIA theory are
captured by the topologically twisted B-model, treating D-branes as objects in
the bounded derived category of coherent sheaves on the compact part of the
target space. The set of basic D-branes wrapped on the homology cycles of the
compact space are taken to reside in the heart of t-structures of the derived
category of coherent sheaves on the space at any point in the K\"ahler moduli
space. The stability data entails specifying a t-structure along with a grade
for sorting the branes. Considering an example of a degenerate Calabi-Yau
space, obtained via geometric engineering, that retains but a projective curve
as the sole non-compact part, we identify the regions in the K\"ahler moduli
space of the curve that pertain to the different t-structures of the bounded
derived category of coherent sheaves on the curve corresponding to the
different phases of the topological branes.


title: 5D Black Holes and Non-linear Sigma Models

abstract:
  Stationary solutions of 5D supergravity with U(1) isometry can be efficiently
studied by dimensional reduction to three dimensions, where they reduce to
solutions to a locally supersymmetric non-linear sigma model. We generalize
this procedure to 5D gauged supergravity, and identify the corresponding
gauging in 3D. We pay particular attention to the case where the Killing spinor
is non constant along the fibration, which results, even for ungauged
supergravity in 5D, in an additional gauging in 3D, without introducing any
extra potential. We further study SU(2)\times U(1) symmetric solutions, which
correspond to geodesic motion on the sigma model (with potential in the gauged
case). We identify and study the algebra of BPS constraints relevant for the
Breckenridge-Myers-Peet-Vafa black hole, the Gutowski-Reall black hole and
several other BPS solutions, and obtain the corresponding radial wave functions
in the semi-classical approximation.


title: Radial Photon Trajectories Near an Evaporating Black Hole

abstract:
  The radial motion of photons emitted near the horizon of a black hole that
evaporates at a steady rate is examined. The space-time of the black hole is
generated using non-orthogonal coordinates. It is shown that some photons that
are initially drawn towards the singularity can escape falling into the
horizon. The behaviors of various outgoing and ingoing photons are clearly
demonstrated through the use of a Penrose diagram.


title:
Zero-knowledge authentication schemes from actions on graphs, groups, or
  rings

abstract:
  We propose a general way of constructing zero-knowledge authentication
schemes from actions of a semigroup on a set, without exploiting any specific
algebraic properties of the set acted upon. Then we give several concrete
realizations of this general idea, and in particular, we describe several
zero-knowledge authentication schemes where forgery (a.k.a. impersonation) is
NP-hard. Computationally hard problems that can be employed in these
realizations include (Sub)graph Isomorphism, Graph Colorability, Diophantine
Problem, and many others.


title:
Magnetic trapping of atomic nitrogen (14^N) and cotrapping of NH
  (X-triplet-Sigma-)

abstract:
  We observe magnetic trapping of atomic nitrogen (14^N) and cotrapping of
ground state imidogen (14^NH, X-triplet-Sigma-). Both are loaded directly from
a room temperature beam via buffer gas cooling. We trap approximately 1 * 10^11
14^N atoms at a peak density of 5 * 10^11 cm^-3 at 550 mK. The 12 +5/-3 s 1/e
lifetime of atomic nitrogen in the trap is limited by elastic collisions with
the helium buffer gas. Cotrapping of 14^N and 14^NH is accomplished, with 10^8
NH trapped molecules at a peak density of 10^8 cm^-3. We observe no spin
relaxation of nitrogen in collisions with helium.


title: Boundary layer on the surface of a neutron star

abstract:
  In an attempt to model the accretion onto a neutron star in low-mass X-ray
binaries, we present two-dimensional hydrodynamical models of the gas flow in
close vicinity of the stellar surface. First we consider a gas pressure
dominated case, assuming that the star is non-rotating. For the stellar mass we
take $M_{\rm star}=1.4 \times 10^{-2} \msun$ and for the gas temperature $T=5
\times 10^6$ K. Our results are qualitatively different in the case of a
realistic neutron star mass and a realistic gas temperature of $T\simeq 10^8$
K, when the radiation pressure dominates. We show that to get the stationary
solution in a latter case, the star most probably has to rotate with the
considerable velocity.


title:
Two-Fluid Behaviour at the Origin of the Resistivity Peak in Doped
  Manganites

abstract:
  We report a series of magnetic and transport measurements on high-quality
single crystal samples of colossal magnetoresistive manganites, La_{0.7}
Ca_{0.3} Mn O_3 and Pr_{0.7} Sr_{0.3} Mn O_3. 1 % Fe doping allows a Moessbauer
spectroscopy study, which shows (i) unusual line broadening within the
ferromagnetic phase and (ii) a coexistence of ferro- and paramagnetic
contributions in a region, T_1<T<T_2, around the Curie point T_C. In the case
of Pr_{0.7} Sr_{0.3} Mn O_3, the resistivity peak occurs at a considerably
higher temperature, T_{MI}>T_2. This shows that phase separation into metallic
(ferromagnetic) and insulating (paramagnetic) phases cannot be generally
responsible for the resistivity peak (and hence for the associated colossal
magnetoresistance). Our results can be understood phenomenologically within the
two-fluid approach, which also allows for a difference between T_C and T_{MI}.
Our data indeed imply that while magnetic and transport properties of the
manganites are closely interrelated, the two transitions at T_C and T_{MI} can
be viewed as distinct phenomena.


title:
Derivatives of (Modified) Fredholm Determinants and Stability of
  Standing and Traveling Waves

abstract:
  Continuing a line of investigation initiated in [11] exploring the
connections between Jost and Evans functions and (modified) Fredholm
determinants of Birman-Schwinger type integral operators, we here examine the
stability index, or sign of the first nonvanishing derivative at frequency zero
of the characteristic determinant, an object that has found considerable use in
the study by Evans function techniques of stability of standing and traveling
wave solutions of partial differential equations (PDE) in one dimension. This
leads us to the derivation of general perturbation expansions for
analytically-varying modified Fredholm determinants of abstract operators. Our
main conclusion, similarly in the analysis of the determinant itself, is that
the derivative of the characteristic Fredholm determinant may be efficiently
computed from first principles for integral operators with semi-separable
integral kernels, which include in particular the general one-dimensional case,
and for sums thereof, which latter possibility appears to offer applications in
the multi-dimensional case.
  A second main result is to show that the multi-dimensional characteristic
Fredholm determinant is the renormalized limit of a sequence of Evans functions
defined in [23] on successive Galerkin subspaces, giving a natural extension of
the one-dimensional results of [11] and answering a question of [27] whether
this sequence might possibly converge (in general, no, but with
renormalization, yes). Convergence is useful in practice for numerical error
control and acceleration.


title: Ice emission and the redshifts of submillimeter sources

abstract:
  Observations at submillimeter wavelengths have revealed a population of
sources thought to be at relatively large redshifts. The position of the 850
$\mu$m passband on the Rayleigh-Jeans portion of the Planck function leads to a
maximum redshift estimate of $z\sim$4.5 since sources will not retain their
redshift independent brightness close to the peak of the Planck function and
thus drop out of surveys. Here we review evidence that ice absorption is
present in the spectra of local ultraluminous infrared galaxies which are often
taken as analogs for the 850 $\mu$m source population. We consider the
implication of this absorption for ice induced spectral structure at far
infrared wavelengths and present marginal astronomical evidence that amorphous
ice may have a feature similar to crystalline ice near 150 $\mu$m. Recent
corroborative laboratory evidence is supportive of this conclusion. It is
argued that early metal enrichment by pair instability SN may lead to a high
ice content relative to refractory dust at high redshift and a fairly robust
detection of ice emission in a $z=6.42$ quasar is presented. It is further
shown that ice emission is needed to understand the 450 $\mu$m sources observed
in the GOODS-N field. We are thus encouraged to apply far infrared ice emission
models to the available observations of HDF 850.1, the brightest submillimeter
source in the {\it Hubble Deep Field}. We suggest that a redshift as large as
13 may need to be considered for this source, nearly a factor of three above
the usual top estimate. Inclusion of the possibility of far infrared ice
emission in the spectral energy distributions of model sources generally
broadens the range of redshifts to be considered for submillimeter sources
compared to models without ice emission.


title:
An empirical study of large, naturally occurring starling flocks: a
  benchmark in collective animal behaviour

abstract:
  Bird flocking is a striking example of collective animal behaviour. A vivid
illustration of this phenomenon is provided by the aerial display of vast
flocks of starlings gathering at dusk over the roost and swirling with
extraordinary spatial coherence. Both the evolutionary justification and the
mechanistic laws of flocking are poorly understood, arguably because of a lack
of data on large flocks. Here, we report a quantitative study of aerial
display. We measured the individual three-dimensional positions in compact
flocks of up to 2700 birds. We investigated the main features of the flock as a
whole - shape, movement, density and structure - and discuss these as emergent
attributes of the grouping phenomenon. We find that flocks are relatively thin,
with variable sizes, but constant proportions. They tend to slide parallel to
the ground and, during turns, their orientation changes with respect to the
direction of motion. Individual birds keep a minimum distance from each other
that is comparable to their wingspan. The density within the aggregations is
non-homogeneous, as birds are packed more tightly at the border compared to the
centre of the flock. These results constitute the first set of large-scale data
on three-dimensional animal aggregations. Current models and theories of
collective animal behaviour can now be tested against these results.


title:
The STARFLAG handbook on collective animal behaviour: Part I, empirical
  methods

abstract:
  The most startling examples of collective animal behaviour are provided by
very large and cohesive groups moving in three dimensions. Paradigmatic
examples are bird flocks, fish schools and insect swarms. However, because of
the sheer technical difficulty of obtaining 3D data, empirical studies
conducted to date have only considered loose groups of a few tens of animals.
Moreover, these studies were very seldom conducted in the field. Recently the
STARFLAG project achieved the 3D reconstruction of thousands of birds under
field conditions, thus opening the way to a new generation of quantitative
studies of collective animal behaviour. Here, we review the main technical
problems in 3D data collection of large animal groups and we outline some of
the methodological solutions adopted by the STARFLAG project. In particular, we
explain how to solve the stereoscopic correspondence - or matching - problem,
which was the major bottleneck of all 3D studies in the past.


title:
M-decomposability, elliptical unimodal densities, and applications to
  clustering and kernel density estimation

abstract:
  Chia and Nakano (2009) introduced the concept of M-decomposability of
probability densities in one-dimension. In this paper, we generalize
M-decomposability to any dimension. We prove that all elliptical unimodal
densities are M-undecomposable. We also derive an inequality to show that it is
better to represent an M-decomposable density via a mixture of unimodal
densities. Finally, we demonstrate the application of M-decomposability to
clustering and kernel density estimation, using real and simulated data. Our
results show that M-decomposability can be used as a non-parametric criterion
to locate modes in probability densities.


title: Symmetric form of governing equations for capillary fluids

abstract:
  In classical continuum mechanics, quasi-linear systems of conservation laws
can be symmetrized if they admit an additional convex conservation law. In
particular, this implies the hyperbolicity of governing equations. For
capillary fluids, the internal energy depends not only on the density but also
on its derivatives with respect to space variables. Consequently, the governing
equations belong to the class of dispersive systems. In that case we propose a
symmetric form of governing equations which is different from the classical
Godunov -Friedrichs - Lax representation. This new symmetric form implies the
stability of constant solutions.


title:
Two--center quantum MICZ--Kepler system and the Zeeman effect in the
  charge-dyon system

abstract:
  The quantum two-center MICZ--Kepler system is considered in the limit when
one of the interaction centers is situated at infinity, which leads to
homogeneous electric and magnetic fields appearing in the system. The emerging
system admits separation of variables in the Schr\"{o}dinger equation and is
integrable at the classical level. The first order corrections to the
unperturbed spectrum of the ordinary MICZ--Kepler system are calculated.
Particularly, the linear Zeeman--effect and effects of MICZ-terms are analyzed.
The possible realizations of the system in some quantum dots are considered.


title: Chern-Simons and WZW Anomaly Cancelations Across Dimensions

abstract:
  The WZW functional in D=4 can be derived directly from the Chern-Simons
functional of a compactified D=5 gauge theory and the boundary fermions it
supplants. A simple pedagogical model based on U(1) gauge groups illustrates
how this works. A bulk-boundary system with the fermions eliminated manifestly
evinces anomaly cancelations between CS and WZW terms.


title: Equivariant cohomology of incidence Hilbert schemes and loop algebras

abstract:
  Let $S$ be the affine plane $\C^2$ together with an appropriate $\mathbb T =
\C^*$ action. Let $\hil{m,m+1}$ be the incidence Hilbert scheme. Parallel to
\cite{LQ}, we construct an infinite dimensional Lie algebra that acts on the
direct sum $$\Wft = \bigoplus_{m=0}^{+\infty}H^{2(m+1)}_{\mathbb
T}(S^{[m,m+1]})$$ of the middle-degree equivariant cohomology group of
$\hil{m,m+1}$. The algebra is related to the loop algebra of an infinite
dimensional Heisenberg algebra. In addition, we study the transformations among
three different linear bases of $\Wft$. Our results are applied to the ring
structure of the ordinary cohomology of $\hil{m,m+1}$ and to the ring of
symmetric functions in infinitely many variables.


title:
The STARFLAG handbook on collective animal behaviour: Part II,
  three-dimensional analysis

abstract:
  The study of collective animal behaviour must progress through a comparison
between the theoretical predictions of numerical models and data coming from
empirical observations. To this aim it is important to develop methods of
three-dimensional (3D) analysis that are at the same time informative about the
structure of the group and suitable to empirical data. In fact, empirical data
are considerably noisier than numerical data, and they are subject to several
constraints. We review here the tools of analysis used by the STARFLAG project
to characterise the 3D structure of large flocks of starlings in the field. We
show how to avoid the most common pitfalls i the quantitative analysis of 3D
animal groups, with particular attention to the problem of the bias introduced
by the border of the group. By means of practical examples, we demonstrate that
neglecting border effects gives rise to artefacts when studying the 3D
structure of a group. Moreover, we show that mathematical rigour is essential
to distinguish important biological properties from trivial geometric features
of animal groups.


title: Stellar Evolution at Low Metallicity

abstract:
  Massive stars played a key role in the early evolution of the Universe. They
formed with the first halos and started the re-ionisation. It is therefore very
important to understand their evolution. In this review, we first recall the
effect of metallicity (Z) on the evolution of massive stars. We then describe
the strong impact of rotation induced mixing and mass loss at very low Z. The
strong mixing leads to a significant production of primary nitrogen 14, carbon
13 and neon 22. Mass loss during the red supergiant stage allows the production
of Wolf-Rayet stars, type Ib,c supernovae and possibly gamma-ray bursts (GRBs)
down to almost Z=0 for stars more massive than 60 solar masses. Galactic
chemical evolution models calculated with models of rotating stars better
reproduce the early evolution of N/O, C/O and C12/C13. Finally, the impact of
magnetic fields is discussed in the context of GRBs.


title: An All Optical Fibre Quantum Controlled-NOT Gate

abstract:
  We report the first experimental demonstration of an optical controlled-NOT
gate constructed entirely in fibre. We operate the gate using two heralded
optical fibre single photon sources and find an average logical fidelity of 90%
and an average process fidelity of 0.83<F<0.91. On the basis of a simple model
we are able to conclude that imperfections are primarily due to the photon
sources, meaning that the gate itself works with very high fidelity.