title: Irregular connections and Kac-Moody root systems

abstract:
  Some moduli spaces of irregular connections on the trivial bundle over the
Riemann sphere will be identified with Nakajima quiver varieties. In particular
this enables us to associate a Kac-Moody root system to such connections
(yielding many isomorphisms between such moduli spaces, via the reflection
functors for the corresponding Weyl group). The possibility of 'reading' a
quiver in different ways also yields numerous isomorphisms between such moduli
spaces, often between spaces of connections on different rank bundles and with
different polar divisors. Finally some results of Crawley-Boevey on the
existence of stable connections will be extended to this more general context.


title:
Non-Abelian structures in compactifications of M-theory on
  seven-manifolds with SU(3) structure

abstract:
  We study M-theory compactified on a specific class of seven-dimensional
manifolds with SU(3) structure. The manifolds can be viewed as a fibration of
an arbitrary Calabi-Yau threefold over a circle, with a U-duality twist around
the circle. In some cases we find that in the four dimensional low energy
effective theory a (broken) non-Abelian gauge group appears. Furthermore, such
compactifications are shown to be dual to previously analyzed compactifications
of the heterotic string on K3 x T^2, with background gauge field fluxes on the
T^2.


title:
Entanglement of distant atoms by projective measurement: The role of
  detection efficiency

abstract:
  We assess proposals for entangling two distant atoms by measurement of
emitted photons, analyzing how their performance depends on the photon
detection efficiency. We consider schemes based on measurement of one or two
photons and compare them in terms of the probability to obtain the detection
event and of the conditional fidelity with which the desired entangled state is
created. Based on an unravelling of the master equation, we quantify the
parameter regimes in which one or the other scheme is more efficient, including
the possible combination of the one-photon scheme with state purification. In
general, protocols based on one-photon detection are more efficient in set-ups
characterized by low photon detection efficiency, while at larger values
two-photon protocols are preferable. We give numerical examples based on
current experiments.


title: Knot homology groups from instantons

abstract:
  For each partial flag manifold of SU(N), we define a Floer homology theory
for knots in 3-manifolds, using instantons with codimension-2 singularities.


title:
The ground state energy of the Edwards-Anderson spin glass model with a
  parallel tempering Monte Carlo algorithm

abstract:
  We study the efficiency of parallel tempering Monte Carlo technique for
calculating true ground states of the Edwards-Anderson spin glass model.
Bimodal and Gaussian bond distributions were considered in two and
three-dimensional lattices. By a systematic analysis we find a simple formula
to estimate the values of the parameters needed in the algorithm to find the GS
with a fixed average probability. We also study the performance of the
algorithm for single samples, quantifying the difference between samples where
the GS is hard, or easy, to find. The GS energies we obtain are in good
agreement with the values found in the literature. Our results show that the
performance of the parallel tempering technique is comparable to more powerful
heuristics developed to find the ground state of Ising spin glass systems.


title: Probing Reionization with the 21 cm-Galaxy Cross Power Spectrum

abstract:
  The cross-correlation between high redshift galaxies and 21 cm emission from
the high redshift intergalactic medium (IGM) promises to be an excellent probe
of the Epoch of Reionization (EoR). On large scales, the 21 cm and galaxy
fields are anti-correlated during most of the reionization epoch. However, on
scales smaller than the size of the H II regions around detectable galaxies,
the two fields become roughly uncorrelated. Consequently, the 21 cm-galaxy
cross power spectrum provides a tracer of bubble growth during reionization,
with the signal turning over on progressively larger scales as reionization
proceeds. The precise turnover scale depends on the minimum host mass of the
detectable galaxies, and the galaxy selection technique. Measuring the turnover
scale as a function of galaxy luminosity constrains the characteristic bubble
size around galaxies of different luminosities. The cross spectrum becomes
positive on small scales if ionizing photons fail to escape from low mass
galaxies, and these galaxies are detectable longward of the hydrogen ionization
edge, because in this case some identifiable galaxies lie outside of ionized
regions. LOFAR can potentially measure the 21 cm-galaxy cross spectrum in
conjunction with mild extensions to the existing Subaru survey for $z=6.6$
Lyman-alpha emitters, while the MWA is slightly less sensitive for detecting
the cross spectrum. A futuristic galaxy survey covering a sizable fraction of
the MWA field of view ($\sim 800$ deg$^2$) can probe the scale dependence of
the cross spectrum, constraining the filling factor of H II regions at
different redshifts during reionization, and providing other valuable
constraints on reionization models.


title:
The Sloan Lens ACS Survey. VIII. The relation between environment and
  internal structure of early-type galaxies

abstract:
  We study the relation between the internal structure of early-type galaxies
and their environment using 70 strong gravitational lenses from the Sloan ACS
Lens Survey. The Sloan database is used to determine two measures of
overdensity of galaxies around each lens: the projected number density of
galaxies inside the tenth nearest neighbor (\Sigma_{10}) and within a cone of
radius one h^{-1} Mpc (D_1). Our main results are: 1) The average overdensity
is somewhat larger than unity, consistent with lenses preferring overdense
environments as expected for massive early-type galaxies (12/70 lenses are in
known groups/clusters). 2) The distribution of overdensities is
indistinguishable from that of "twin" non-lens galaxies selected from SDSS to
have the same redshift and stellar velocity dispersion \sigma_*. Thus, within
our errors, lens galaxies are an unbiased population, and the SLACS results can
be generalized to the overall population of early-type galaxies. 3) Typical
contributions from external mass distribution are no more than a few per cent,
reaching 10-20% (~0.05-0.10 external convergence) only in the most extreme
overdensities. 4) No significant correlation between overdensity and slope of
the mass density profile of the lens is found. 5) Satellite galaxies (those
with a more luminous companion) have marginally steeper mass density profiles
than central galaxies (those without). This result suggests that tidal
stripping may affect the mass structure of early-type galaxies down to kpc
scales probed by strong lensing, when they fall into larger structures
[ABRIDGED].


title:
Study of chargino-neutralino production at hadron colliders in a
  long-lived slepton scenario

abstract:
  The differential cross section of the chargino-neutralino production, q qbar
--> chi+- chi0, followed by their decays into scalar tau leptons, chi+- chi0
--> (stau+- nu)(stau-+ tau+-) --> (stau+- nu)(stau-+ l+- nu nubar), is
calculated including the effect of spin correlations. In the case where stau is
long-lived, this final state can be fully reconstructed in a hadron-collider
experiment up to a discrete two-fold ambiguity. Distributions of various
kinematic variables can thus be observable and tell us about masses and spins
of superparticles and also parity/CP violation in interactions by comparing
with the cross-section formula. Observing non-trivial distributions derived in
this paper will be a good test of supersymmetry.


title: The Vortex Lattice in Ginzburg-Landau Superconductors

abstract:
  Abrikosov's solution of the linearized Ginzburg-Landau theory describing a
periodic lattice of vortex lines in type-II superconductors at large
inductions, is generalized to non-periodic vortex arrangements, e.g., to
lattices with a vacancy surrounded by relaxing vortices and to periodically
distorted lattices that are needed in the nonlocal theory of elasticity of the
vortex lattice. Generalizations to lower magnetic inductions and to
three-dimensional arrangements of curved vortex lines are also given. Finally,
it is shown how the periodic vortex lattice can be computed for bulk
superconductors and for thick and thin films in a perpendicular field for all
inductions B and Ginzburg-Landau parameters kappa.


title:
Discovery of Two Nearby, Peculiar L Dwarfs from the 2MASS Proper Motion
  Survey: Young or Metal-Rich?

abstract:
  We present the discovery of two nearby L dwarfs from our 2MASS proper motion
search, which uses multi-epoch 2MASS observations covering ~4700 square degrees
of sky. 2MASS J18212815+1414010 and 2MASS J21481628+4003593 were overlooked by
earlier surveys due to their faint optical magnitudes and their proximity to
the Galactic Plane (10 degrees < |b| < 15 degrees). Assuming that both dwarfs
are single, we derive spectrophotometric distances of ~10 pc, thus increasing
the number of known L dwarfs within 10 pc to 10. In the near-infrared, 2MASS
J21481628+4003593 shows a triangular-shaped H-band spectrum, strong CO
absorption, and a markedly red J-Ks color (2.38+/-0.06) for its L6 optical
spectral type. 2MASS J18212815+1414010 also shows a triangular-shaped H-band
spectrum and a slightly red J-Ks color (1.78+/-0.05) for its L4.5 optical
spectral type. Both objects show strong silicate absorption at 9-11 microns.
Cumulatively, these features imply an unusually dusty photosphere for both of
these objects. We examine several scenarios to explain the underlying cause for
their enhanced dust content and find that a metal-rich atmosphere or a
low-surface gravity are consistent with these results. 2MASS J18212815+1414010
may be young (and therefore have a low-surface gravity) based on its low
tangential velocity of 10 km/s. On the other hand, 2MASS J21481628+4003593 has
a high tangential velocity of 62 km/s and is therefore likely old. Hence, high
metallicity and low-surface gravity may lead to similar effects.


title: Solvable Limit for SU(N) Kondo Model

abstract:
  We study a single channel one dimensional Kondo Model where the impurity spin
is replaced by an su(n) spin. Using Abelian bosonization and canonical
transformation we explicitly show that this system has an exactly solvable
point. The calculation also shows that there are $n$ collective excitation
modes in the system, one charged and $n-1$ neutral spin excitation modes.


title:
Primordial non-Gaussianity: large-scale structure signature in the
  perturbative bias model

abstract:
  I compute the effect on the power spectrum of tracers of the large-scale
mass-density field (e.g., galaxies) of primordial non-Gaussianity of the form
Phi=phi+fNL (phi-<phi^2>)+gNL phi^3+..., where Phi is proportional to the
initial potential fluctuations and phi is a Gaussian field, using
beyond-linear-order perturbation theory. I find that the need to eliminate
large higher-order corrections necessitates the addition of a new term to the
bias model, proportional to phi, i.e., delta_g=b_delta delta+b_phi fNL phi+...,
with all the consequences this implies for clustering statistics, e.g.,
P_gg(k)=b_delta^2 P_deltadelta(k)+2 b_delta b_phi fNL P_phidelta(k)+b_phi^2
fNL^2 P_phiphi(k)+... . This result is consistent with calculations based on a
model for dark matter halo clustering, showing that the form is quite general,
not requiring assumptions about peaks, or the formation or existence of halos.
The halo model plays the same role it does in the usual bias picture, giving a
prediction for b_phi for galaxies known to sit in a certain type of halo.
Previous projections for future constraints based on this effect have been very
conservative -- there is enough volume at z<~2 to measure fNL to ~+-1, with
much more volume at higher z. As a prelude to the bias calculation, I point out
that the beyond-linear (in phi) corrections to the power spectrum of
mass-density perturbations are naively infinite, so it is dangerous to assume
they are negligible; however, the infinite part can be removed by a
renormalization of the fluctuation amplitude, with the residual k-dependent
corrections negligible for models allowed by current constraints.


title:
Capacity of Block-Memoryless Channels with Causal Channel Side
  Information

abstract:
  The capacity of a time-varying block-memoryless channel in which the
transmitter and the receiver have access to (possibly different) noisy causal
channel side information (CSI) is obtained. It is shown that the capacity
formula obtained in this correspondence reduces to the capacity formula
reported in \cite{Gold07} for the special case where the transmitter CSI is a
deterministic function of the receiver CSI.


title:
A cellular automata model for avascular solid tumor growth under the
  effect of therapy

abstract:
  Tumor growth has long been a target of investigation within the context of
mathematical and computer modelling. The objective of this study is to propose
and analyze a two-dimensional probabilistic cellular automata model to describe
avascular solid tumor growth, taking into account both the competition between
cancer cells and normal cells for nutrients and/or space and a time-dependent
proliferation of cancer cells. Gompertzian growth, characteristic of some
tumors, is described and some of the features of the time-spatial pattern of
solid tumors, such as compact morphology with irregular borders, are captured.
The parameter space is studied in order to analyze the occurrence of necrosis
and the response to therapy. Our findings suggest that transitions exist
between necrotic and non-necrotic phases (no-therapy cases), and between the
states of cure and non-cure (therapy cases). To analyze cure, the control and
order parameters are, respectively, the highest probability of cancer cell
proliferation and the probability of the therapeutic effect on cancer cells.
With respect to patterns, it is possible to observe the inner necrotic core and
the effect of the therapy destroying the tumor from its outer borders inwards.


title:
Landau's Last Paper and its Impact on Developments in Mathematics,
  Physics and Other Disciplines in New Millennium

abstract:
  In this paper we discuss the impact of the last Landau paper on physics and
mathematics to date and make some predictions about its likely impact on
sciences in new millennium.


title: B2FH, the Cosmic Microwave Background and Cosmology

abstract:
  In this talk I shall start by describing how we set about and carried out the
work which led to the publication of B2FH in 1957. I then shall try and relate
this work and the circumstances that surrounded it to the larger problem of the
origin and formation of the universe. Here it is necessary to look back at the
way that ideas developed and how in many situations astronomers went astray. Of
course this is a personal view, though I very strongly believe that if he were
still here, it is the approach that Fred Hoyle would take.
  I start by describing the problems originally encountered by Gamow and his
associates in trying to decide where the helium was made. This leads me to a
modern discussion of the origin of 2D, 3He, 4He and 7Li, originally described
by B2FH as due to the x-process. While it is generally argued, following Gamow,
Alpher, and Herman, that these isotopes were synthesized in a big bang I shall
show that it is equally likely that these isotopes were made in active galactic
nuclei, as was the cosmic microwave background (CMB), in a cyclic universe
model. The key piece of observational evidence is that the amount of energy
carried by the CMB, namely about 4.5 x 10-13 erg cm-3


title: Metaferroelectrics: Artificial Ferroelectricity in Metamaterials

abstract:
  Metamaterials are artificial periodic structures which represent effective
homogeneous medium for electromagnetic fields. Here I show that there exists an
important class of such composite systems, metaferroelectrics. They are
properly designed metamaterials with non-ferroelectric constituents which,
nevertheless, exhibit ferroelectric response. Furthermore, for relatively small
samples the effect is anisotropic and strongly depends on the sample shape.
Metaferroelectrics will help to understand deeper the physics of
ferroelectricity and show enormous potential for applications in the field of
nano-optoelectronics.


title: Stable quarks of the 4th family?

abstract:
  Existence of metastable quarks of new generation can be embedded into
phenomenology of heterotic string together with new long range interaction,
which only this new generation possesses. We discuss primordial quark
production in the early Universe, their successive cosmological evolution and
astrophysical effects, as well as possible production in present or future
accelerators. In case of a charge symmetry of 4th generation quarks in
Universe, they can be stored in neutral mesons, doubly positively charged
baryons, while all the doubly negatively charged "baryons" are combined with
He-4 into neutral nucleus-size atom-like states. The existence of all these
anomalous stable particles may escape present experimental limits, being close
to present and future experimental test. Due to the nuclear binding with He-4
primordial lightest baryons of the 4th generation with charge +1 can also
escape the experimental upper limits on anomalous isotopes of hydrogen, being
compatible with upper limits on anomalous lithium. While 4th quark hadrons are
rare, their presence may be nearly detectable in cosmic rays, muon and neutrino
fluxes and cosmic electromagnetic spectra. In case of charge asymmetry, a
nontrivial solution for the problem of dark matter (DM) can be provided by
excessive (meta)stable anti-up quarks of 4th generation, bound with He-4 in
specific nuclear-interacting form of dark matter. Such candidate to DM is
surprisingly close to Warm Dark Matter by its role in large scale structure
formation. It catalyzes primordial heavy element production in Big Bang
Nucleosynthesis and new types of nuclear transformations around us.


title:
Noise spectra of stochastic pulse sequences: application to large scale
  magnetization flips in the finite size 2D Ising model

abstract:
  We provide a general scheme to predict and derive the contribution to the
noise spectrum of a stochastic sequence of pulses from the distribution of
pulse parameters. An example is the magnetization noise spectra of a 2D Ising
system near its phase transition. At $T\le T_c$, the low frequency spectra is
dominated by magnetization flips of nearly the entire system. We find that both
the predicted and the analytically derived spectra fit those produced from
simulations. Subtracting this contribution leaves the high frequency spectra
which follow a power law set by the critical exponents.


title:
Gyrokinetic turbulence: a nonlinear route to dissipation through phase
  space

abstract:
  This paper describes a conceptual framework for understanding kinetic plasma
turbulence as a generalized form of energy cascade in phase space. It is
emphasized that conversion of turbulent energy into thermodynamic heat is only
achievable in the presence of some (however small) degree of collisionality.
The smallness of the collision rate is compensated by the emergence of
small-scale structure in the velocity space. For gyrokinetic turbulence, a
nonlinear perpendicular phase mixing mechanism is identified and described as a
turbulent cascade of entropy fluctuations simultaneously occurring at spatial
scales smaller than the ion gyroscale and in velocity space. Scaling relations
for the resulting fluctuation spectra are derived. An estimate for the
collisional cutoff is provided. The importance of adequately modeling and
resolving collisions in gyrokinetic simulations is biefly discussed, as well as
the relevance of these results to understanding the dissipation-range
turbulence in the solar wind and the electrostatic microturbulence in fusion
plasmas.

categories: physics.plasm-ph astro-ph nlin.CD physics.space-ph


title: A Minimal Model for the Study of Polychronous Groups

abstract:
  A minimal model of polychronous groups in neural networks is presented. The
model is computationally efficient and allows the study of polychronous groups
independent of specific neuron models. Computational experiments were performed
with the model in one- and two-dimensional neural architectures to determine
the dependence of the number of polychronous groups on various connectivity
options. The possibility of using polychronous groups as computational elements
is also discussed.


title: Histograms and Wavelets on Probabilistic Data

abstract:
  There is a growing realization that uncertain information is a first-class
citizen in modern database management. As such, we need techniques to correctly
and efficiently process uncertain data in database systems. In particular, data
reduction techniques that can produce concise, accurate synopses of large
probabilistic relations are crucial. Similar to their deterministic relation
counterparts, such compact probabilistic data synopses can form the foundation
for human understanding and interactive data exploration, probabilistic query
planning and optimization, and fast approximate query processing in
probabilistic database systems.
  In this paper, we introduce definitions and algorithms for building
histogram- and wavelet-based synopses on probabilistic data. The core problem
is to choose a set of histogram bucket boundaries or wavelet coefficients to
optimize the accuracy of the approximate representation of a collection of
probabilistic tuples under a given error metric. For a variety of different
error metrics, we devise efficient algorithms that construct optimal or near
optimal B-term histogram and wavelet synopses. This requires careful analysis
of the structure of the probability distributions, and novel extensions of
known dynamic-programming-based techniques for the deterministic domain. Our
experiments show that this approach clearly outperforms simple ideas, such as
building summaries for samples drawn from the data distribution, while taking
equal or less time.


title:
Impact of Rotation on Neutrino Emission and Relic Neutrino Background
  from Population III Stars

abstract:
  We study the effects of rotation on the neutrino emission from Population III
(Pop III) stars by performing a series of two-dimensional rotational collapse
simulations of Pop III stellar cores. Our results show that rotation enhances
the neutrino luminosities and the average energies of emitted neutrinos. This
is because the thermalized inner core, which is the dominant neutrino source
from Pop III stars, can be enlarged, due to rotational flattening, enough to
extend the inner core outside the neutrinospheres. This is in sharp contrast to
the case of spherical collapse, in which the case of inner core shrinks deeper
inside the neutrinospheres before black hole formation, which hinders the
efficient neutrino emission. In the case of rotational core-collapse, the
emitted neutrino energies are found to become larger in the vicinity near the
pole than the ones near the equatorial plane. These factors make the emergent
neutrino spectrum broader and harder than the spherical collapse case. By
computing the overall neutrino signals produced by the ensemble of individual
rotating Pop III stars, we find that the amplitudes of the relic neutrinos,
depending on their star formation rates, can dominate over the contributions
from ordinary core-collapse supernovae below a few MeV. A detection of this
signal could be an important tool to probe star formation history in the early
universe.


title: The Physics of Wind-Fed Accretion

abstract:
  We provide a brief review of the physical processes behind the radiative
driving of the winds of OB stars and the Bondi-Hoyle-Lyttleton capture and
accretion of a fraction of the stellar wind by a compact object, typically a
neutron star, in detached high-mass X-ray binaries (HMXBs). In addition, we
describe a program to develop global models of the radiatively-driven
photoionized winds and accretion flows of HMXBs, with particular attention to
the prototypical system Vela X-1. The models combine XSTAR photoionization
calculations, HULLAC emission models appropriate to X-ray photoionized plasmas,
improved models of the radiative driving of photoionized winds, FLASH
time-dependent adaptive-mesh hydrodynamics calculations, and Monte Carlo
radiation transport. We present two- and three-dimensional maps of the density,
temperature, velocity, ionization parameter, and emissivity distributions of
representative X-ray emission lines, as well as synthetic global Monte Carlo
X-ray spectra. Such models help to better constrain the properties of the winds
of HMXBs, which bear on such fundamental questions as the long-term evolution
of these binaries and the chemical enrichment of the interstellar medium.


title: Magnetic ordering of weakly coupled frustrated quantum spin chains

abstract:
  The ordering temperature of a quasi-one-dimensional system, consisting of
weakly interacting quantum spin-1/2 chains with antiferromagnetic
spin-frustrating couplings (or zig-zag ladder) is calculated. The results show
that a quantum critical point between two phases of the one-dimensional
subsystem plays a crucial role. If the one-dimensional subsystem is in the
antiferromagnetic-like phase in the ground state, similar to the phase of a
spin chain without frustration, weak couplings yield magnetic ordering of the
Neel type. For intra-chain spin-frustrating interactions larger than the
critical one (at which the quantum phase transition takes place), the
quasi-one-dimensional spin system manifests a spiral magnetic incommensurate
ordering. The obtained results of our quantum theory are compared with the
quasi-classical approximations. The calculated features of magnetic ordering
are expected to be generic for weakly coupled quantum spin chains with gapless
excitations and spin-frustrating nearest and next-nearest neighbor
interactions.


title: Two-dimensional one-component plasma on a Flamm's paraboloid

abstract:
  We study the classical non-relativistic two-dimensional one-component plasma
at Coulomb coupling Gamma=2 on the Riemannian surface known as Flamm's
paraboloid which is obtained from the spatial part of the Schwarzschild metric.
At this special value of the coupling constant, the statistical mechanics of
the system are exactly solvable analytically. The Helmholtz free energy
asymptotic expansion for the large system has been found. The density of the
plasma, in the thermodynamic limit, has been carefully studied in various
situations.


title: Secure Quantum Passwords

abstract:
  We propose a quantum authentication protocol that is robust against the theft
of secret keys. In the protocol, disposable quantum passwords prevent
impersonation attacks with stolen secret keys. The protocol also prevents the
leakage of secret information of a certification agent.


title: Edge states of zigzag bilayer graphite nanoribbons

abstract:
  Electronic structures of the zigzag bilayer graphite nanoribbons(Z-BGNR) with
various ribbon width $N$ are studied within the tight binding approximation.
Neglecting the inter-layer hopping amplitude $\gamma_4$, which is an order of
magnitude smaller than the other inter-layer hopping parameters $\gamma_1$ and
$\gamma_3$, there exist two fixed Fermi points $\pm k^*$ independent of the
ribbon width with the peculiar energy dispersion near $k^*$ as $\ve (k) \sim
\pm (k-k^*)^N$. By investigating the edge states of the Z-BGNR, we notice that
the trigonal warping of the bilayer graphene sheets are reflected on in the
edge state structure. With the inclusion of $\gamma_4$, the above two Fermi
points are not fixed, but drift toward the vicinity of the Dirac point with the
increase of the width $N$ as shown by the finite scaling method and the
peculiar dispersions change to the parabolic ones. The edge magnetism of the
Z-BGNR is also examined by solving the half-filled Hubbard Hamiltonian for the
ribbon using the Hartree-Fock approximation. We have shown that within the same
side of the edges, the edge spins are aligned ferromagnetically for the
experimentally relevant set of parameters.


title:
Center vortices as sources of Abelian dominance in pure SU(2) Yang-Mills
  theory

abstract:
  We argue that in the infrared regime of continuum Yang-Mills theory, the
possibility of a mass gap in the charged sector is closely associated with the
center vortex sector.
  The analysis of the possible consequences of the ensembles of defects is done
by showing that the description of center vortices and monopoles is naturally
unified by means of a careful treatment of Cho decomposition.
  If on the one hand confinement is usually associated with monopole
condensation in a compact abelian model, in this scenario, the previous
decoupling of the off-diagonal degrees of freedom, for the abelian model
dominate at large distances, can be understood as induced by a phase where
center vortices become thick objects.
  Other important scenarios for correlated monopoles and center vortices,
observed in lattice simulations, are also accomodated in our general
formulation.


title: AQFT from n-functorial QFT

abstract:
  There are essentially two different approaches to the axiomatization of
quantum field theory (QFT): algebraic QFT, going back to Haag and Kastler, and
functorial QFT, going back to Atiyah and Segal. More recently, based on ideas
by Baez and Dolan, the latter is being refined to "extended" functorial QFT by
Freed, Hopkins, Lurie and others. The first approach uses local nets of
operator algebras which assign to each patch an algebra "of observables", the
latter uses n-functors which assign to each patch a "propagator of states".
  In this note we present an observation about how these two axiom systems are
naturally related: we demonstrate under mild assumptions that every
2-dimensional extended Minkowskian QFT 2-functor ("parallel surface transport")
naturally yields a local net. This is obtained by postcomposing the propagation
2-functor with an operation that mimics the passage from the Schroedinger
picture to the Heisenberg picture in quantum mechanics.
  The argument has a straightforward generalization to general
pseudo-Riemannian structure and higher dimensions.


title: Phantom Energy Accretion onto Black Holes in Cyclic Universe

abstract:
  Black holes pose a serious problem in the cyclic or oscillating cosmology. It
is speculated that, in the cyclic universe with phantom turnarounds, black
holes will be torn apart by the phantom energy before turnaround before they
can create any problems. In this paper, using the mechanism of the phantom
accretion onto black holes, we find that black holes do not disappear before
the phantom turnaround. But the remanent black holes will not cause any
problems due to the Hawking evaporation.


title:
Could Fermion Masses Play a Role in the Stabilization of the Dilaton in
  Cosmology?

abstract:
  We study the possibility that the Dilaton is stabilized by the contribution
of fermion masses to its effective potential. We consider the Dilaton gravity
action in four dimensions to which we add a mass term for a Dirac fermion. Such
an action describes the interaction of the Dilaton with the fermions in the
Yang-Mills sector of the coupled supergravity/super-Yang-Mills action which
emerges as the low energy effective action of superstring theory after the
extra spatial dimensions have been fixed. The Dilaton couples to the Fermion
mass term via the usual exponential factor of this field which multiplies the
non-kinetic terms of the matter Lagrangian, if we work in the Einstein frame.
In the kinetic part of the Fermion action in the Einstein frame the Dilaton
does not enter. Such masses can be generated in several ways: they can arise as
a consequence of flux about internal spatial dimensions, they may arise as
thermal fermion masses in a quasi-static phase in the early universe, and they
will arise after the breaking of supersymmetry at late times. The vacuum
contribution to the potential for the Dilaton is evaluated up to two loops. The
result shows a minimum which could stabilize the Dilaton for reasonable ranges
of parameter values.


title:
Homological stability of non-orientable mapping class groups with marked
  points

abstract:
  Wahl recently proved that the homology of the non-orientable mapping class
group stabilizes as the genus increases. In this short note we analyse the
situation where the underlying non-orientable surfaces have marked points.


title: On Robustness Properties of Beta Encoders and Golden Ratio Encoders

abstract:
  The beta-encoder was recently proposed as a quantization scheme for
analog-to-digital conversion; in contrast to classical binary quantization, in
which each analog sample x in [-1,1] is mapped to the first N bits of its
base-2 expansion, beta-encoders replace each sample x with its expansion in a
base beta satisfying 1 < beta < 2. This expansion is non-unique when 1 < beta <
2, and the beta-encoder exploits this redundancy to correct inevitable errors
made by the quantizer component of its circuit design.
  The multiplier element of the beta-encoder will also be imprecise;
effectively, the true value beta at any time can only be specified to within an
interval [ beta_{low}, beta_{high} ]. This problem was addressed by the golden
ratio encoder, a close relative of the beta-encoder that does not require a
precise multiplier. However, the golden ratio encoder is susceptible to
integrator leak in the delay elements of its hardware design, and this has the
same effect of changing beta to an unknown value.
  In this paper, we present a method whereby exponentially precise
approximations to the value of beta in both golden ratio encoders and beta
encoders can be recovered amidst imprecise circuit components from the
truncated beta-expansions of a "test" number x_{test} in [-1,1], and its
negative counterpart, -x_{test}. That is, beta-encoders and golden ratio
encoders are robust with respect to unavoidable analog component imperfections
that change the base beta needed for reconstruction.


title:
Restoration of $hc/2e$ Magnetic Flux Periodicity in a Hollow $d$-Wave
  Superconducting Cylinder

abstract:
  The magnetic flux dependence of order parameter and supercurrent is studied
in a hollow d-wave superconducting cylinder. It is shown that the existence of
line nodal quasiparticles in a pure $d_{x^2-y^2}$ pairing state gives rise to
an $hc/e$ periodicity in the order parameter and a first-order quantum phase
transition for a large system size. We demonstrate that the flux periodicity in
the supercurrent is sensitive to the detailed electronic band structure and
electron filling factor. In particular, we find that, in cooperation with the
increase of the cylinder circumference, the $hc/2e$ periodicity can be restored
significantly in the supercurrent by avoiding the particle-hole symmetry point.
A similar study of a $d_{x^2-y^2}+id_{xy}$ pairing state verifies the
peculiarity of unconventional superconductors with nodal structure.


title: Finite-size Effects for Single Spike

abstract:
  We use the reduction of the string dynamics on R_t x S^3 to the
Neumann-Rosochatius integrable system to map all string solutions described by
this dynamical system onto solutions of the complex sine-Gordon integrable
model. This mapping relates the parameters in the solutions on both sides of
the correspondence. In the framework of this approach, we find finite-size
string solutions, their images in the (complex) sine-Gordon system, and the
leading finite-size effects of the single spike "E-\Delta\phi" relation for
both R_t x S^2 and R_t x S^3 cases.


title:
Reduction of the gravitational lens equation to a one-dimensional
  non-linear form for the tilted Plummer model family

abstract:
  The gravitational lens equation for the tilted Plummer family of models can
be reduced to a one-dimensional non-linear equation. For certain values of the
slope of the radial profile it can be reduced to a polynomial form. Both forms
are advantageous to find the roots, i.e. the images for a given model. The
critical curve equations can also be reduced to a non-linear or polynomial
form, and therefore it is useful to find the caustics. This lens model family
has ample use in gravitational lens theory, and can produce up to five images.


title: Surface Solitons in Three Dimensions

abstract:
  We study localized modes on the surface of a three-dimensional dynamical
lattice. The stability of these structures on the surface is investigated and
compared to that in the bulk of the lattice. Typically, the surface makes the
stability region larger, an extreme example of that being the three-site
"horseshoe"-shaped structure, which is always unstable in the bulk, while at
the surface it is stable near the anti-continuum limit. We also examine effects
of the surface on lattice vortices. For the vortex placed parallel to the
surface this increased stability region feature is also observed, while the
vortex cannot exist in a state normal to the surface. More sophisticated
localized dynamical structures, such as five-site horseshoes and pyramids, are
also considered.


title: Unmixed bipartite graphs and sublattices of the Boolean lattices

abstract:
  The correspondence between unmixed bipartite graphs and sublattices of the
oolean lattice is discussed. By using this correspondence, we show the
existence of squarefree quadratic initial ideals of toric ideals arising from
minimal vertex covers of unmixed bipartite graphs.


title:
Fair and Efficient TCP Access in the IEEE 802.11 Infrastructure Basic
  Service Set

abstract:
  When the stations in an IEEE 802.11 infrastructure Basic Service Set (BSS)
employ Transmission Control Protocol (TCP) in the transport layer, this
exacerbates per-flow unfair access which is a direct result of uplink/downlink
bandwidth asymmetry in the BSS. We propose a novel and simple analytical model
to approximately calculate the per-flow TCP congestion window limit that
provides fair and efficient TCP access in a heterogeneous wired-wireless
scenario. The proposed analysis is unique in that it considers the effects of
varying number of uplink and downlink TCP flows, differing Round Trip Times
(RTTs) among TCP connections, and the use of delayed TCP Acknowledgment (ACK)
mechanism. Motivated by the findings of this analysis, we design a link layer
access control block to be employed only at the Access Point (AP) in order to
resolve the unfair access problem. The novel and simple idea of the proposed
link layer access control block is employing a congestion control and filtering
algorithm on TCP ACK packets of uplink flows, thereby prioritizing the access
of TCP data packets of downlink flows at the AP. Via simulations, we show that
short- and long-term fair access can be provisioned with the introduction of
the proposed link layer access control block to the protocol stack of the AP
while improving channel utilization and access delay.


title: Uniting Old Stellar Systems: From Globular Clusters to Giant Ellipticals

abstract:
  Here we examine the relationship between the virial and stellar mass for a
range of old stellar systems, from GCs to giant ellipticals, and including such
Intermediate Mass Objects (IMOs). Improvements on previous work in this area
include the use of (i) near-infrared magnitudes from the 2MASS survey, (ii)
aperture corrections to velocity dispersions, (iii) homogeneous half light
radii and (iv) accounting for the effects of non-homology in galaxies. We find
a virial-to-stellar mass relation that ranges from ~10$^4$ M_o systems (GCs) to
~10$^11$ M_o systems (elliptical galaxies). The lack of measured velocity
dispersions for dwarf ellipticals with -16 > M_K > -18 (~10$^8$ M_o) currently
inhibits our ability to determine how, or indeed if, these galaxies connect
continuously with GCs in terms of their virial-to-stellar mass ratios. We find
elliptical galaxies to have roughly equal fractions of dark and stellar matter
within a virial radius; only in the most massive (greater than 10$^11$ M_o)
ellipticals does dark matter dominate the virial mass. Although the IMOs reveal
slightly higher virial-to-stellar mass ratios than lower mass GCs, this may
simply reflect our limited understanding of their IMF (and hence their stellar
mass-to-light ratios) or structural properties. We argue that most of these
intermediate mass objects are a natural extension of the GC sequence to higher
masses, i.e. IMOs are essentially massive star clusters. [Abridged].


title:
Universal approximation of multi-copy states and universal quantum
  lossless data compression

abstract:
  We have proven that there exists a quantum state approximating any multi-copy
state universally when we measure the error by means of the normalized relative
entropy. While the qubit case was proven by Krattenthaler and Slater (IEEE
Trans. IT, 46, 801-819 (2000); quant-ph/9612043), the general case has been
open for more than ten years. For a deeper analysis, we have solved the
mini-max problem concerning `approximation error' up to the second order.
Furthermore, we have applied this result to quantum lossless data compression,
and have constructed a universal quantum lossless data compression.


title: Incremental Stochastic Subgradient Algorithms for Convex Optimization

abstract:
  In this paper we study the effect of stochastic errors on two constrained
incremental sub-gradient algorithms. We view the incremental sub-gradient
algorithms as decentralized network optimization algorithms as applied to
minimize a sum of functions, when each component function is known only to a
particular agent of a distributed network. We first study the standard cyclic
incremental sub-gradient algorithm in which the agents form a ring structure
and pass the iterate in a cycle. We consider the method with stochastic errors
in the sub-gradient evaluations and provide sufficient conditions on the
moments of the stochastic errors that guarantee almost sure convergence when a
diminishing step-size is used. We also obtain almost sure bounds on the
algorithm's performance when a constant step-size is used. We then consider
\ram{the} Markov randomized incremental subgradient method, which is a
non-cyclic version of the incremental algorithm where the sequence of computing
agents is modeled as a time non-homogeneous Markov chain. Such a model is
appropriate for mobile networks, as the network topology changes across time in
these networks. We establish the convergence results and error bounds for the
Markov randomized method in the presence of stochastic errors for diminishing
and constant step-sizes, respectively.


title:
Fair Access Provisioning through Contention Parameter Adaptation in the
  IEEE 802.11e Infrastructure Basic Service Set

abstract:
  We present the station-based unfair access problem among the uplink and the
downlink stations in the IEEE 802.11e infrastructure Basic Service Set (BSS)
when the default settings of the Enhanced Distributed Channel Access (EDCA)
parameters are used. We discuss how the transport layer protocol
characteristics alleviate the unfairness problem. We design a simple,
practical, and standard-compliant framework to be employed at the Access Point
(AP) for fair and efficient access provisioning. A dynamic measurement-based
EDCA parameter adaptation block lies in the core of this framework. The
proposed framework is unique in the sense that it considers the characteristic
differences of Transmission Control Protocol (TCP) and User Datagram Protocol
(UDP) flows and the coexistence of stations with varying bandwidth or
Quality-of-Service (QoS) requirements. Via simulations, we show that our
solution provides short- and long-term fair access for all stations in the
uplink and downlink employing TCP and UDP flows with non-uniform packet rates
in a wired-wireless heterogeneous network. In the meantime, the QoS
requirements of coexisting real-time flows are also maintained.


title: Hyperon-nucleon force from lattice QCD

abstract:
  We calculate potentials between a proton and a $\Xi^0$ (hyperon with
strangeness -2) through the equal-time Bethe-Salpeter wave function, employing
quenched lattice QCD simulations with the plaquette gauge action and the Wilson
quark action on (4.5 fm)^4 lattice at the lattice spacing $a \simeq 0.14$ fm.
The ud quark mass in our study corresponds to $m_{\pi}\simeq 0.37$ and 0.51
GeV, while the s quark mass corresponds to the physical value of $m_K$. The
central $p \Xi^0$ potential has a strong (weak) repulsive core in the $^1S_0$
($^3S_1$) channel for $r \lsim 0.6$ fm, while the potential has attractive well
at the medium and long distances (0.6 fm $\lsim r \lsim 1.2$ fm) in both
channels. The sign of the $p \Xi^0$ scattering length and its quark mass
dependence indicate a net attraction in both channels at low energies.


title:
Numerical Simulations of a Protostellar Outflow Colliding with a Dense
  Molecular Cloud

abstract:
  High-resolution SiO observations of the NGC 1333 IRAS 4A star-forming region
showed a highly collimated outflow with a substantial deflection. The
deflection was suggested to be caused by the interactions of the outflow and a
dense cloud core. To investigate the deflection process of protostellar
outflows, we have carried out three-dimensional hydrodynamic simulations of the
collision of an outflow with a dense cloud. Assuming a power-law type density
distribution of the obstructing cloud, the numerical experiments show that the
deflection angle is mainly determined by the impact parameter and the density
contrast between the outflow and the cloud. The deflection angle is, however,
relatively insensitive to the velocity of the outflow. Using a numerical model
with physical conditions that are particularly suitable for the IRAS 4A system,
we produce a column-density image and a position-velocity diagram along the
outflow, and they are consistent with the observations. Based on our numerical
simulations, if we assume that the initial density and the velocity of the
outflow are $\sim 10 \cm3$ and $\sim 100 \kms$, the densities of the dense core
and ambient medium in the IRAS 4A system are most likely to be $\sim 10^5 \cm3$
and $\sim 10^2 \cm3$, respectively. We therefore demonstrate through numerical
simulations that the directional variability of the IRAS 4A outflow can be
explained reasonably well using the collision model.


title: Scale-free patterns at a saddle-node bifurcation in a stochastic system

abstract:
  We demonstrate that scale-free patterns are observed in a spatially extended
stochastic system whose deterministic part undergoes a saddle-node bifurcation.
Remarkably, the scale-free patterns appear only at a particular time in
relaxation processes from a spatially homogeneous initial condition. We
characterize the scale-free nature in terms of the spatial configuration of the
exiting time from a marginal saddle where the pair annihilation of a saddle and
a node occurs at the bifurcation point. Critical exponents associated with the
scale-free patterns are determined by numerical experiments.


title:
Detection of two-photon exclusive production of supersymmetric pairs at
  the LHC

abstract:
  The detection of pairs of sleptons, charginos and charged higgs bosons
produced via photon-photon fusion at the LHC is studied, assuming a couple of
benchmark points of the MSSM model. Due to low cross sections, it requires
large integrated luminosity, but thanks to the striking signature of these
exclusive processes the backgrounds are low, and are well known. Very forward
proton detectors can be used to measure the photon energies, allowing for
direct determination of masses of the lightest SUSY particle, of selectrons and
smuons with a few GeV resolution. Finally, the detection and mass measurement
of quasi-stable particles predicted by the so-called sweet spot supersymmetry
is discussed.


title: Diphoton Generalized Distribution Amplitudes

abstract:
  We calculate the leading order diphoton generalized distribution amplitude by
calculating the amplitude of the process gamma* gamma -> gamma gamma in the low
energy and high photon virtuality region at the Born order and in the leading
logarithmic approximation. As in the case of the anomalous photon structure
functions, the gamma gamma generalized distribution amplitude exhibits a
characteristic \ln Q^2 behaviour and obeys inhomogeneous evolution equations.


title:
Magnetic moment of hyperons in nuclear matter by using quark-meson
  coupling models

abstract:
  We calculate the magnetic moments of hyperons in dense nuclear matter by
using relativistic quark models. Hyperons are treated as MIT bags, and the
interactions are considered to be mediated by the exchange of scalar and vector
mesons which are approximated as mean fields. Model dependence is investigated
by using the quark-meson coupling model and the modified quark-meson coupling
model; in the former the bag constant is independent of density and in the
latter it depends on density. Both models give us the magnitudes of the
magnetic moments increasing with density for most octet baryons. But there is a
considerable model dependence in the values of the magnetic moments in dense
medium. The magnetic moments at the nuclear saturation density calculated by
the quark meson coupling model are only a few percents larger than those in
free space, but the magnetic moments from the modified quark meson coupling
model increase more than 10% for most hyperons. The correlations between the
bag radius of hyperons and the magnetic moments of hyperons in dense matter are
discussed.


title: Design Patterns for Complex Event Processing

abstract:
  Currently engineering efficient and successful event-driven applications
based on the emerging Complex Event Processing (CEP) technology, is a laborious
trial and error process. The proposed CEP design pattern approach should
support CEP engineers in their design decisions to build robust and efficient
CEP solutions with well understood tradeoffs and should enable an
interdisciplinary and efficient communication process about successful CEP
solutions in different application domains.


title:
Exact results in a slave boson saddle point approach for a strongly
  correlated electron model

abstract:
  We revisit the Kotliar-Ruckenstein (KR) slave boson saddle point evaluation
for a two-site correlated electron model. As the model can be solved
analytically, it is possible to compare the KR saddle point results to the
exact many particle levels. The considered two site cluster mimics an
infinite-$U$ single-impurity Anderson model with a nearest neighbor Coulomb
interaction: one site is strongly correlated with an infinite local Coulomb
repulsion which hybridizes with the second site, on which the local Coulomb
repulsion vanishes. Making use of the flexibility of the representation we
introduce appropriate weight factors in the KR saddle point scheme. Ground
state and all excitation levels agree with the exact diagonalization results.
Thermodynamics and correlation functions may be recovered in a suitably
renormalized saddle point evaluation.


title: Multiple Nash-equilibrium in Quantum Game

abstract:
  Methods of exploring Nash equilibrium in quantum games are studied.
Analytical conditions of the existence, the uniqueness or the multiplicity of
the equilibria are found.


title: On the Approximability of Comparing Genomes with Duplicates

abstract:
  A central problem in comparative genomics consists in computing a
(dis-)similarity measure between two genomes, e.g. in order to construct a
phylogeny. All the existing measures are defined on genomes without duplicates.
However, we know that genes can be duplicated within the same genome. One
possible approach to overcome this difficulty is to establish a one-to-one
correspondence (i.e. a matching) between genes of both genomes, where the
correspondence is chosen in order to optimize the studied measure. In this
paper, we are interested in three measures (number of breakpoints, number of
common intervals and number of conserved intervals) and three models of
matching (exemplar, intermediate and maximum matching models). We prove that,
for each model and each measure M, computing a matching between two genomes
that optimizes M is APX-hard. We also study the complexity of the following
problem: is there an exemplarization (resp. an intermediate/maximum matching)
that induces no breakpoint? We prove the problem to be NP-Complete in the
exemplar model for a new class of instances, and we show that the problem is in
P in the maximum matching model. We also focus on a fourth measure: the number
of adjacencies, for which we give several approximation algorithms in the
maximum matching model, in the case where genomes contain the same number of
duplications of each gene.


title:
Characteristics of the eigenvalue distribution of the Dirac operator in
  dense two-color QCD

abstract:
  We exposit the eigenvalue distribution of the lattice Dirac operator in
Quantum Chromodynamics with two colors (i.e. two-color QCD). We explicitly
calculate all the eigenvalues in the presence of finite quark chemical
potential \mu for a given gauge configuration on the finite-volume lattice.
First, we elaborate the Banks-Casher relations in the complex plane extended
for the diquark condensate as well as the chiral condensate to relate the
eigenvalue spectral density to the physical observable. Next, we evaluate the
condensates and clarify the characteristic spectral change corresponding to the
phase transition. Assuming the strong coupling limit, we exhibit the numerical
results for a random gauge configuration in two-color QCD implemented by the
staggered fermion formalism and confirm that our results agree well with the
known estimate quantitatively. We then exploit our method in the case of the
Wilson fermion formalism with two flavors. Also we elucidate the possibility of
the Aoki (parity-flavor broken) phase and conclude from the point of view of
the spectral density that the artificial pion condensation is not induced by
the density effect in strong-coupling two-color QCD.


title: Overview of Beam Dynamics Studies at DAFNE

abstract:
  Since several years the DAFNE Team has been discussing ideas and performing
experimental activities aimed at the collider luminosity increase. In this
paper we briefly describe the proposed ideas and discuss results of the most
relevant beam dynamics experimental studies that have been carried at DAFNE. We
also introduce the concept of crab waist collisions that is the base of the
undergoing DAFNE upgrade.


title:
Temperature dependence of the energy dissipation in dynamic force
  microscopy

abstract:
  The dissipation of energy in dynamic force microscopy is usually described in
terms of an adhesion hysteresis mechanism. This mechanism should become less
efficient with increasing temperature. To verify this prediction we have
measured topography and dissipation data with dynamic force microscopy in the
temperature range from 100 K up to 300 K. We used
3,4,9,10-perylenetetracarboxylic-dianhydride (PTCDA) grown on KBr(001), both
materials exhibiting a strong dissipation signal at large frequency shifts. At
room temperature, the energy dissipated into the sample (or tip) is 1.9
eV/cycle for PTCDA and 2.7 eV/cycle for KBr, respectively, and is in good
agreement with an adhesion hysteresis mechanism. The energy dissipation over
the PTCDA surface decreases with increasing temperature yielding a negative
temperature coefficient. For the KBr substrate, we find the opposite behaviour:
an increase of dissipated energy with increasing temperature. While the
negative temperature coefficient in case of PTCDA agrees rather well with the
adhesion hysteresis model, the positive slope found for KBr points to a
hitherto unknown dissipation mechanism.


title: Conductive nanodots on the surface of irradiated CaF2

abstract:
  CaF2(111) single crystal surfaces have been irradiated with swift heavy ions
under oblique angles resulting in chains of nanosized hillocks. In order to
characterize these nanodots with respect to their conductivity we have applied
non-contact atomic force microscopy using a magnetic tip. Measurements in UHV
as well as under ambient conditions reveal a clearly enhanced electromagnetic
interaction between the magnetic tip and the nanodots. The dissipated energy
per cycle is comparable to the value found for metals, indicating that the
interaction of the ion with the target material leads to the creation of
metallic Ca nanodots on the surface.


title: Charmful Three-body Baryonic B decays

abstract:
  We study the charmful three-body baryonic B decays with $D^{(*)}$ or $J/\Psi$
in the final state. We explain the measured rates of $\bar B^0\to n\bar p
D^{*+}$, $\bar B^0\to p\bar p D^{(*)0}$, and $B^-\to \Lambda \bar p J/\Psi$ and
predict the branching fractions of $\bar B^0\to \Lambda\bar p D^{*+}$, $\bar
B^0\to \Sigma^0\bar p D^{*+}$, $B^-\to\Lambda \bar p D^{0}$, and $B^-\to\Lambda
\bar p D^{*0}$ to be of order $(1.2, 1.1, 1.1, 3.9)\times 10^{-5}$,
respectively. They are readily accessible to the $B$ factories.


title: Two-phase coexistence in the hard-disk model

abstract:
  A two-dimensional system of 10000 hard disks with square periodic boundary
conditions, at a density in the middle of the 2-phase region predicted from
equation-of-state data, when subjected to a weak external uniform force, is
seen to phase separate. Thermodynamic profiles of the inhomogeneous two-phase
system agree with the local density approximation (LDA) of density functional
theory. There is no indication of any mesophase.


title:
Dynamic photoconductive gain effect in shallow-etched AlGaAs/GaAs
  quantum wires

abstract:
  We report on a dynamic photoconductive gain effect in quantum wires which are
lithographically fabricated in an AlGaAs/GaAs quantum well via a shallow-etch
technique. The effect allows resolving the one-dimensional subbands of the
quantum wires as maxima in the photoresponse across the quantum wires. We
interpret the results by optically induced holes in the valence band of the
quantum well which shift the chemical potential of the quantum wire. The
non-linear current-voltage characteristics of the quantum wires also allow
detecting the photoresponse effect of excess charge carriers in the conduction
band of the quantum well. The dynamics of the photoconductive gain are limited
by the recombination time of both electrons and holes.


title: Distance dependence of the phase signal in eddy current microscopy

abstract:
  Atomic force microscopy using a magnetic tip is a promising tool for
investigating conductivity on the nano-scale. By the oscillating magnetic tip
eddy currents are induced in the conducting parts of the sample which can be
detected in the phase signal of the cantilever. However, the origin of the
phase signal is still controversial because theoretical calculations using a
monopole appoximation for taking the electromagnetic forces acting on the tip
into account yield an effect which is too small by more than two orders of
magnitude. In order to determine the origin of the signal we used especially
prepared gold nano patterns embedded in a non-conducting polycarbonate matrix
and measured the distance dependence of the phase signal. Our data clearly
shows that the interacting forces are long ranged and therefore, are likely due
to the electromagnetic interaction between the magnetic tip and the conducting
parts of the surface. Due to the long range character of the interaction a
change in conductivity of $\Delta\sigma=4,5\cdot10^{7} (\Omega$m$)^{-1}$ can be
detected far away from the surface without any interference from the
topography.


title: Radiative and Auger decay data for modelling nickel K lines

abstract:
  Radiative and Auger decay data have been calculated for modelling the K lines
in ions of the nickel isonuclear sequence, from Ni$^+$ up to Ni$^{27+}$. Level
energies, transition wavelengths, radiative transition probabilities, and
radiative and Auger widths have been determined using Cowan's Hartree--Fock
with Relativistic corrections (HFR) method. Auger widths for the third-row ions
(Ni$^+$--Ni$^{10+}$) have been computed using single-configuration average
(SCA) compact formulae. Results are compared with data sets computed with the
AUTOSTRUCTURE and MCDF atomic structure codes and with available experimental
and theoretical values, mainly in highly ionized ions and in the solid state.


title: On the stability of shocks with particle pressure

abstract:
  We perform a linear stability analysis for corrugations of a Newtonian shock,
with particle pressure included, for an arbitrary diffusion coefficient. We
study first the dispersion relation for homogeneous media, showing that,
besides the conventional pressure waves and entropy/vorticity disturbances, two
new perturbation modes exist, dominated by the particles' pressure and damped
by diffusion. We show that, due to particle diffusion into the upstream region,
the fluid will be perturbed also upstream: we treat these perturbation in the
short wavelength (WKBJ) regime. We then show how to construct a corrugational
mode for the shock itself, one, that is, where the shock executes free
oscillations (possibly damped or growing) and sheds perturbations away from
itself: this global mode requires the new modes. Then, using the perturbed
Rankine-Hugoniot conditions, we show that this leads to the determination of
the corrugational eigenfrequency. We solve numerically the equations for the
eigenfrequency in the WKBJ regime for the models of Amato and Blasi (2005),
showing that they are stable. We then discuss the differences between our
treatment and previous work.


title:
Finite size Berezinski-Kosterlitz-Thouless transition at grain
  boundaries in solid $^4$He and role of $^3$He impurities

abstract:
  We analyze the complex phenomenology of the Non-Classical Rotational Inertia
(NCRI) observed at low temperature in solid $^4$He within the context of a two
dimensional Berezinski-Kosterlitz-Thouless transition in a premelted $^4$He
film at the grain boundaries. We show that both the temperature and $^3$He
doping dependence of the NCRI fraction (NCRIF) can be ascribed to finite size
effects induced by the finite grain size. We give an estimate of the average
size of the grains which we argue to be limited by the isotopic $^3$He
impurities and we provide a simple power-law relation between the NCRIF and the
$^3$He concentration.


title: Searching Hidden-sector Photons inside a Superconducting Box

abstract:
  We propose an experiment to search for extra "hidden-sector" U(1) gauge
bosons with gauge kinetic mixing with the ordinary photon, predicted by many
extensions of the Standard Model. The setup consists of a highly sensitive
magnetometer inside a superconducting shielding. This is then placed inside a
strong (but sub-critical) magnetic field. In ordinary electrodynamics the
magnetic field cannot permeate the superconductor and no field should register
on the magnetometer. However, photon -- hidden-sector photon -- photon
oscillations would allow to penetrate the superconductor and the magnetic field
would "leak" into the shielded volume and register on the magnetometer.
Although this setup resembles a classic ``light shining though a wall
experiment'' there are two crucial differences. First, the fields are (nearly)
static and the photons involved are virtual. Second, the magnetometer directly
measures the field-strength and not a probability. This improves the dependence
of the signal on the kinetic mixing chi (\ll 1) to chi^2 instead of chi^4. For
hidden photon masses in the range 0.002-200 meV the projected sensitivity for
the mixing parameter lies in the 5 10^-9 to 10^-6 range. This surpasses current
astrophysical and laboratory limits by several orders of magnitude -- ample
room to discover new physics.


title: Elliptic flow in nuclear collisions at the Large Hadron Collider

abstract:
  We use perfect-fluid hydrodynamical model to predict the elliptic flow
coefficients in Pb + Pb collisions at the Large Hadron Collider (LHC). The
initial state for the hydrodynamical calculation for central $A + A$ collisions
is obtained from the perturbative QCD + saturation (EKRT) model. The centrality
dependence of the initial state is modeled by the optical Glauber model. We
show that the baseline results obtained from the framework are in good
agreement with the data from the Relativistic Heavy Ion Collider (RHIC), and
show predictions for the $p_T$ spectra and elliptic flow of pions in Pb + Pb
collisions at the LHC. Also mass and multiplicity effects are discussed.


title: Nonholonomic Constraints: a New Viewpoint

abstract:
  The purpose of this paper is to show that, at least for Lagrangians of
mechanical type, nonholonomic Euler-Lagrange equations for a nonholonomic
linear constraint D may be viewed as non-constrained Euler-Lagrange equations
but on a new (generally not Lie) algebroid structure on D. The proposed novel
formalism allows us to treat in a unified way a variety of situations in
nonholonomic mechanics and gives rise to a version of Neoether Theorem
producing actual first integrals in case of symmetries.


abstract:
  We found Groebner-Shirshov basis for the braid semigroup $B^+_{n+1}$. It
gives a new algorithm for the solution of the word problem for the braid
semigroup and so for the braid group.


title: Entropy of charged dilaton-axion black hole

abstract:
  Using brick wall method the entropy of charged dilaton-axion black hole is
determined for both asymptotically flat and non-flat cases. The entropy turns
out to be proportional to the horizon area of the black hole confirming the
Beckenstien, Hawking area-entropy formula for black holes. The leading order
logarithmic corrections to the entropy are also derived for such black holes.


title: Cosmography by GRBs

abstract:
  Relations connecting gamma ray burst quantities can be used to constrain
cosmographic parameters of the Hubble law at medium-high redshifts. We consider
a sample of 27 gamma ray bursts to construct the luminosity distance to
redshift relation and derive the values of the parameters $q_0$, $j_0$, and
$s_0$. The analysis is compared with other methods in the literature. gamma gay
bursts, if calibrated by SNeIa, seem reliable as distance indicators and give
cosmographic parameters in agreement with the $\Lambda$CDM model.


title:
Ground-state hyperfine structure of H-, Li-, and B-like ions in middle-Z
  region

abstract:
  The hyperfine splitting of the ground state of H-, Li-, and B-like ions is
investigated in details within the range of nuclear numbers Z = 7-28. The
rigorous QED approach together with the large-scale configuration-interaction
Dirac-Fock-Sturm method are employed for the evaluation of the
interelectronic-interaction contributions of first and higher orders in 1/Z.
The screened QED corrections are evaluated to all orders in (\alpha Z)
utilizing an effective potential approach. The influence of nuclear
magnetization distribution is taken into account within the single-particle
nuclear model. The specific differences between the hyperfine-structure level
shifts of H- and Li-like ions, where the uncertainties associated with the
nuclear structure corrections are significantly reduced, are also calculated.


title:
On the KP I transonic limit of two-dimensional Gross-Pitaevskii
  travelling waves

abstract:
  We provide a rigorous mathematical derivation of the convergence in the
long-wave transonic limit of the minimizing travelling waves for the
two-dimensional Gross-Pitaevskii equation towards ground states for the
Kadomtsev-Petviashvili equation (KP I).


title:
Groebner-Shirshov basis for the braid group in the Birman-Ko-Lee-Garside
  generators

abstract:
  In this paper, we obtain Groebner-Shirshov (non-commutative Gr\"obner) bases
for the braid groups in the Birman-Ko-Lee generators enriched by new ``Garside
word" $\delta$. It gives a new algorithm for getting the Birman-Ko-Lee Normal
Form in the braid groups, and thus a new algorithm for solving the word problem
in these groups.


title: Markov and Artin normal form theorem for braid groups

abstract:
  In this paper we will present the results of Artin--Markov on braid groups by
using the Groebner--Shirshov basis. As a consequence we can reobtain the normal
form of Artin--Markov--Ivanovsky as an easy corollary.


title:
Groebner-Shirshov basis for the braid group in the Artin-Garside
  generators

abstract:
  In this paper, we give a Groebner-Shirshov basis of the braid group $B_{n+1}$
in the Artin--Garside generators. As results, we obtain a new algorithm for
getting the Garside normal form, and a new proof that the braid semigroup
$B^+{n+1}$ is the subsemigroup in $B_{n+1}$.


title:
Ultratransparent glass-ceramics: the structure factor and the quenching
  of the Rayleigh scattering

abstract:
  Glass-ceramics with nanocrystals present a transparency higher than that
expected from the theory of Rayleigh scattering. This ultra-transparency is
attributed to the spatial correlation of the nanoparticles. The structure
factor is calculated for a simple model system, the random sequential addition
of equal spheres, at different volume filling factor. The spatial correlation
given by the constraint that particles cannot superimpose produces a
diffraction peak with a low $S(q)$ in its low-$q$ tail, which is relevant for
light scattering. The physical mechanism producing high transparency in
glass-ceramics is demonstrated to be the low density fluctuation in the number
of scatterers.


title: Multivariate Splines and Polytopes

abstract:
  In this paper, we use multivariate splines to investigate the volume of
polytopes. We first present an explicit formula for the multivariate truncated
power, which can be considered as a dual version of the famous Brion's formula
for the volume of polytopes. We also prove that the integration of polynomials
over polytopes can be dealt with by the multivariate truncated power. Moreover,
we show that the volume of the cube slicing can be considered as the maximum
value of the box spline. Based on this connection, we give a simple proof for
Good's conjecture, which has been settled by probability methods.


title:
Whispering-gallery modes and light emission from a Si-nanocrystal-based
  single microdisk resonator

abstract:
  We report on visible light emission from Si-nanocrystal based optically
active microdisk resonators. The room temperature photoluminescence (PL) from
single microdisks shows the characteristic modal structure of
whispering-gallery modes. The emission is both TE and TM-polarized in 300 nm
thick microdisks, while thinner ones (135 nm) support only TE-like modes.
Thinner disks have the advantage to filter out higher order radial mode
families, allowing for measuring only the most intense first order modal
structure. We reveal subnanometer linewidths and corresponding quality factors
as high as 2800, limited by the spectral resolution of the experimental setup.
Moreover,we observe a modification of mode linewidth by a factor 13 as a
function of pump power. The origin of this effect is attributed to an excited
carrier absorption loss mechanism.


title: On the evolutionary status of short period cataclysmic variables

abstract:
  (Abridged) We present high-speed, three-colour photometry of seven short
period (Porb <= 95 mins) eclipsing CVs from the Sloan Digital Sky Survey. We
determine the system parameters via a parametrized model of the eclipse fitted
to the observed lightcurve by chi2 minimization. Three out of seven of the
systems possess brown dwarf donor stars and are believed to have evolved past
the orbital period minimum. This is in line with predictions that 40-70 per
cent of CVs should have evolved past the orbital period minimum. Therefore, the
main result of our study is that the missing population of post-period minimum
CVs has finally been identified. The donor star masses and radii are, however,
inconsistent with model predictions; the donor stars are approximately 10 per
cent larger than expected across the mass range studied here. One explanation
for the discrepancy is enhanced angular momentum loss (e.g. from circumbinary
discs), however the mass-transfer rates, as deduced from white dwarf effective
temperatures, are not consistent with enhanced angular momentum loss. We show
it is possible to explain the large donor radii without invoking enhanced
angular momentum loss by a combination of geometrical deformation and the
effects of starspots due to strong rotation and expected magnetic activity.
Choosing unambiguously between these different solutions will require
independent estimates of the mass-transfer rates in short period CVs.


title: Order in the mass spectrum of elementary particles

abstract:
  The study on the linkage of elementary particle mass differences with
pion-muon mass difference is explored further. In the present study we show
this linkage to be equally true for the mass differences amongst the members of
SU(3) hadron multiplets and the hadrons belonging to multiplets having
different spin and parity characteristics. This reinforces our contention that
inter particle mass excitations are quantized as integral multiples of basic
mass unit of 29.318 MeV and thereby indicates the fundamental nature of
pion-muon mass difference in the elementary particle mass distribution.


title:
Newtonian mechanics & gravity fully model disk galaxy rotation curves
  without dark matter

abstract:
  EGRET gamma-ray archival data used with GALPROP software show two ringlike
structures in Milky Way Plane which roughly tally with distribution of stars
([1] & references therein). To understand fully the implications of this and
similar results on detailed structure and rotation curve of especially Milky
Way Disk as well as rotation curves of other galaxies as derived from spatially
resolved spectroscopic data-cubes, a re-examination of the basis of the
connection between mass density and rotation curve is warranted. Kenneth F.
Nicholson's approach [2], which uses only Newtonian dynamics & gravity, is
presented.


title:
Linear Stability of Equilibrium Points in the Generalized
  Photogravitational Chermnykh's Problem

abstract:
  The equilibrium points and their linear stability has been discussed in the
generalized photogravitational Chermnykh's problem. The bigger primary is being
considered as a source of radiation and small primary as an oblate spheroid.
The effect of radiation pressure has been discussed numerically. The collinear
points are linearly unstable and triangular points are stable in the sense of
Lyapunov stability provided $\mu< \mu_{Routh}=0.0385201$. The effect of
gravitational potential from the belt is also examined. The mathematical
properties of this system are different from the classical restricted three
body problem.


title: Macroscopic control parameter for avalanche models for bursty transport

abstract:
  Similarity analysis is used to identify the control parameter $R_A$ for the
subset of avalanching systems that can exhibit Self- Organized Criticality
(SOC). This parameter expresses the ratio of driving to dissipation. The
transition to SOC, when the number of excited degrees of freedom is maximal, is
found to occur when $R_A \to 0$. This is in the opposite sense to (Kolmogorov)
turbulence, thus identifying a deep distinction between turbulence and SOC and
suggesting an observable property that could distinguish them.
  A corollary of this similarity analysis is that SOC phenomenology, that is,
power law scaling of avalanches, can persist for finite $R_A$, with the same
$R_A \to 0$ exponent, if the system supports a sufficiently large range of
lengthscales; necessary for SOC to be a candidate for physical ($R_A$ finite)
systems.


title: Non-collinearity in high energy processes

abstract:
  We discuss the treatment of intrinsic transverse momenta in high energy
scattering processes. Within the field theoretical framework of QCD the process
is described in terms of correlators containing quark and gluon fields. The
correlators, parameterized in terms of distribution and fragmentation
functions, contain matrix elements of nonlocal field configurations requiring a
careful treatment to assure color gauge invariance. It leads to nontrivial
gauge links connecting the parton fields. For the transverse momentum dependent
correlators the gauge links give rise to time reversal odd phenomena, showing
up as single spin and azimuthal asymmetries. The gauge links, arising from
multi-gluon initial and final state interactions, depend on the color flow in
the process, challenging universality.


title:
A sextupole ion beam guide to improve the efficiency and beam quality at
  IGISOL

abstract:
  The laser ion source project at the IGISOL facility, Jyvaskyla, has motivated
the development and construction of an rf sextupole ion beam guide (SPIG) to
replace the original skimmer electrode. The SPIG has been tested both off-line
and on-line in proton-induced fission, light-ion and heavy-ion induced
fusion-evaporation reactions and, in each case, has been directly compared to
the skimmer system. For both fission and light-ion induced fusion, the SPIG has
improved the mass-separated ion yields by a factor of typically 4 to 8.
Correspondingly, the transmission efficiency of both systems has been studied
in simulations with and without space charge effects. The transport capacity of
the SPIG has been experimentally determined to be 10^12 ions/s before space
charge effects start to take effect. A direct comparison with the simulation
has been made using data obtained via light-ion fusion evaporation. Both
experiment and simulation show an encouraging agreement as a function of
current extracted from the ion guide.


title:
Conductance through atomic point contacts between fcc(100) electrodes of
  gold

abstract:
  Electrical conductance through various nanocontacts between gold electrodes
is studied by using the density functional theory, scalar-relativistic
pseudopotentials, generalized gradient approximation for the
exchange-correlation energy and the recursion-transfer-matrix method along with
channel decomposition. The nanocontact is modeled with pyramidal fcc(100) tips
and 1 to 5 gold atoms between the tips. Upon elongation of the contact by
adding gold atoms between the tips, the conductance at Fermi energy E_F evolves
from G ~ 3 G_0 to G ~ 1 G_0 (G_0 = 2e/h^2). Formation of a true one-atom point
contact, with G ~ 1 G_0 and only one open channel, requires at least one atom
with coordination number 2 in the wire. Tips that share a common vertex atom or
tips with touching vertex atoms have three partially open conductance channels
at E_F, and the symmetries of the channels are governed by the wave functions
of the tips. The long 5-atom contact develops conductance oscillations and
conductance gaps in the studied energy range -3 < E-E_F < 5 eV, which reflects
oscillations in the local density of electron states in the 5-atom linear "gold
molecule" between the electrodes, and a weak coupling of this "molecule" to the
tips.


title: On Inflation Potentials in Randall-Sundrum Braneworld Model

abstract:
  We study the inflationary dynamics of the universe in the Randall-Sandrum
typeII Braneworld model. We consider both an inverse-power law and exponential
potentials and apply the Slow-Roll approximation in high energy limit to derive
analytical expression of relevant inflationary quantities. An upper bound for
the coupling constant was also obtained and a numerical value of perturbation
spectrum is calculated in good agreement with observation.


title: Enhanced Diffusion of a Needle in a Planar Course of Point Obstacles

abstract:
  The transport of an infinitely thin, hard rod in a random, dense array of
point obstacles is investigated by molecular dynamics simulations. Our model
mimics the sterically hindered dynamics in dense needle liquids. The
center-of-mass diffusion exhibits a minimum, and transport becomes increasingly
fast at higher densities. The diffusion coefficient diverges according to a
power law in the density with an approximate exponent of 0.8. This observation
is connected with a new divergent time scale, reflected in a zig-zag motion of
the needle, a two-step decay of the velocity-autocorrelation function, and a
negative plateau in the non-Gaussian parameter.


title: Significant Diagnostic Counterexamples in Probabilistic Model Checking

abstract:
  This paper presents a novel technique for counterexample generation in
probabilistic model checking of Markov Chains and Markov Decision Processes.
(Finite) paths in counterexamples are grouped together in witnesses that are
likely to provide similar debugging information to the user. We list five
properties that witnesses should satisfy in order to be useful as debugging
aid: similarity, accuracy, originality, significance, and finiteness. Our
witnesses contain paths that behave similar outside strongly connected
components.
  This papers shows how to compute these witnesses by reducing the problem of
generating counterexamples for general properties over Markov Decision
Processes, in several steps, to the easy problem of generating counterexamples
for reachability properties over acyclic Markov Chains.


title:
Derivation of Distances with the Tully-Fisher Relation: The Antlia
  Cluster

abstract:
  The Tully-Fisher relation is a correlation between the luminosity and the HI
21cm line width in spiral galaxies (LLW relation). It is used to derive galaxy
distances in the interval 7 to 100 Mpc. Closer, the Cepheids, TRGB and Surface
Brightness Fluctuation methods give a better accuracy. Further, the SNIa are
luminous objects still available for distance measurement purposes, though with
a dramatically lower density grid of measurements on the sky. Galaxies in
clusters are all at the same distance from the observer. Thus the distance of
the cluster derived from a large number of galaxies (N) has an error reduced
according to the square root of N. However, not all galaxies in a cluster are
suitable for the LLW measurement. The selection criteria we use are explained
hereafter; the important point being to avoid Malmquist bias and to not
introduce any systematics in the distance measurement.


title:
Limit theorems for sample eigenvalues in a generalized spiked population
  model

abstract:
  In the spiked population model introduced by Johnstone (2001),the population
covariance matrix has all its eigenvalues equal to unit except for a few fixed
eigenvalues (spikes). The question is to quantify the effect of the
perturbation caused by the spike eigenvalues. Baik and Silverstein (2006)
establishes the almost sure limits of the extreme sample eigenvalues associated
to the spike eigenvalues when the population and the sample sizes become large.
In a recent work (Bai and Yao, 2008), we have provided the limiting
distributions for these extreme sample eigenvalues. In this paper, we extend
this theory to a {\em generalized} spiked population model where the base
population covariance matrix is arbitrary, instead of the identity matrix as in
Johnstone's case. New mathematical tools are introduced for establishing the
almost sure convergence of the sample eigenvalues generated by the spikes.


title:
Local Aronson-B\'enilan estimates and entropy formulae for porous medium
  and fast diffusion equations on manifolds

abstract:
  In this work we derive local gradient and Laplacian estimates of the
Aronson-B\'enilan and Li-Yau type for positive solutions of porous medium
equations posed on Riemannian manifolds with a lower Ricci curvature bound. We
also prove similar results for some fast diffusion equations. Inspired by
Perelman's work we discover some new entropy formulae for these equations.


title: Optically tunable surfaces with trapped particles in microcavities

abstract:
  We introduce optically tunable surfaces based upon metallic gold
nanoparticles trapped in open, water-filled gold cavities. The optical
properties of the surfaces change dramatically with the presence and location
of the particles inside the cavities. The precise position of the particles is
shown to be controllable through optical forces exerted by external
illumination, thus leading to all-optical tunability, whereby the optical
response of the surfaces is tuned through externally applied light. We discuss
the performance of the cavity-particle complex in detail and provide
theoretical support for its application as a novel concept of large-scale
optically tunable system.


title: GRID-Launcher v.1.0

abstract:
  GRID-launcher-1.0 was built within the VO-Tech framework, as a software
interface between the UK-ASTROGRID and a generic GRID infrastructures in order
to allow any ASTROGRID user to launch on the GRID computing intensive tasks
from the ASTROGRID Workbench or Desktop. Even though of general application, so
far the Grid-Launcher has been tested on a few selected softwares
(VONeural-MLP, VONeural-SVM, Sextractor and SWARP) and on the SCOPE-GRID.


title: Optical cloaking with metamaterials

abstract:
  In this contribution, we present the design of cylindrical electromagnetic
cloaks working at optical frequencies, making use of layered structures of
plasmonic and non-plasmonic materials. The simulated results confirm the
validity of the proposed approach and show a rather broad-band behavior of the
cloaking device.


title:
Comment to: "A note on failure of the ladder approximation to QCD"
  [Phys. Lett. B 640 (2006) 196 ]

abstract:
  In the paper [Hong-Shi Zong, Wei-Min Sun, Phys. Lett. B 640 (2006) 196], the
authors claim that our proof of the inconsistency of the ladder approximation
to QCD [Phys. Lett. B 611 (2005) 129] was incorrect. However, their claim is
based on a derivation which contains a rough mathematical mistake, namely the
unjustified change of variables in the divergent (though regularized)
integrals. In this comment I will show this explicitly, so our conclusion that
the ladder approximation to QCD is inconsistent remains, of course, correct.


title: Making Sense of the Legendre Transform

abstract:
  The Legendre transform is an important tool in theoretical physics, playing a
critical role in classical mechanics, statistical mechanics, and
thermodynamics. Yet, in typical undergraduate or graduate courses, the power of
motivation and elegance of the method are often missing, unlike the treatments
frequently enjoyed by Fourier transforms. We review and modify the presentation
of Legendre transforms in a way that explicates the formal mathematics,
resulting in manifestly symmetric equations, thereby clarifying the structure
of the transform algebraically and geometrically. Then we bring in the physics
to motivate the transform as a way of choosing independent variables that are
more easily controlled. We demonstrate how the Legendre transform arises
naturally from statistical mechanics and show how the use of dimensionless
thermodynamic potentials leads to more natural and symmetric relations.


title: Unsatisfiable CNF Formulas need many Conflicts

abstract:
  A pair of clauses in a CNF formula constitutes a conflict if there is a
variable that occurs positively in one clause and negatively in the other. A
CNF formula without any conflicts is satisfiable. The Lovasz Local Lemma
implies that a k-CNF formula is satisfiable if each clause conflicts with at
most 2^k/e-1 clauses. It does not, however, give any good bound on how many
conflicts an unsatisfiable formula has globally. We show here that every
unsatisfiable k-CNF formula requires 2.69^k conflicts and there exist
unsatisfiable k-CNF formulas with 3.51^k conflicts.


title:
Channeling of Protons Through Carbon Nanotubes Embedded in Dielectric
  Media

abstract:
  We investigate how the dynamic polarization of the carbon atoms valence
electrons affects the spatial distributions of protons channeled in the (11, 9)
single-wall carbon nanotubes placed in vacuum and embedded in various
dielectric media. The initial proton speed is varied between 3 and 8 a.u.,
corresponding to the energies between 0.223 and 1.59 MeV, respectively, while
the nanotube length is varied between 0.1 and 0.8 $\mu$m. The spatial
distributions of channeled protons are generated using a computer simulation
method, which includes the numerical solving of the proton equations of motion
in the transverse plane. We show that the dynamic polarization effect can
strongly affect the rainbow maxima in the spatial distributions, so as to
increase the proton flux at the distances from the nanotube wall of the order
of a few tenths of a nanometer at the expense of the flux at the nanotube
center. While our findings are connected to the possible applications of
nanosized ion beams created with the nanotubes embedded in various dielectric
media for biomedical research and in materials modification, they also open the
prospects of applying ion channeling for detecting and locating the atoms and
molecules intercalated inside the nanotubes.


title: Alternative fidelity measure for quantum states

abstract:
  We propose an alternative fidelity measure (namely, a measure of the degree
of similarity) between quantum states and benchmark it against a number of
properties of the standard Uhlmann-Jozsa fidelity. This measure is a simple
function of the linear entropy and the Hilbert-Schmidt inner product between
the given states and is thus, in comparison, not as computationally demanding.
It also features several remarkable properties such as being jointly concave
and satisfying all of "Jozsa's axioms". The trade-off, however, is that it is
supermultiplicative and does not behave monotonically under quantum operations.
In addition, new metrics for the space of density matrices are identified and
the joint concavity of the Uhlmann-Jozsa fidelity for qubit states is
established.


title: Self-consistent theory of molecular switching

abstract:
  We study the model of a molecular switch comprised of a molecule with a soft
vibrational degree of freedom coupled to metallic leads. In the presence of
strong electron-ion interaction, different charge states of the molecule
correspond to substantially different ionic configurations, which can lead to
very slow switching between energetically close configurations (Franck-Condon
blockade). Application of transport voltage, however, can drive the molecule
far out of thermal equilibrium and thus dramatically accelerate the switching.
The tunneling electrons play the role of a heat bath with an effective
temperature dependent on the applied transport voltage. Including the
transport-induced "heating" selfconsistently, we determine the stationary
current-voltage characteristics of the device, and the switching dynamics for
symmetric and asymmetric devices. We also study the effects of an extra
dissipative environment and demonstrate that it can lead to enhanced
non-linearities in the transport properties of the device and dramatically
suppress the switching dynamics.


title: Radiationless energy exchange in three-soliton collisions

abstract:
  We revisit the problem of the three-soliton collisions in the weakly
perturbed sine-Gordon equation and develop an effective three-particle model
allowing to explain many interesting features observed in numerical simulations
of the soliton collisions. In particular, we explain why collisions between two
kinks and one antikink are observed to be practically elastic or strongly
inelastic depending on relative initial positions of the kinks. The fact that
the three-soliton collisions become more elastic with an increase in the
collision velocity also becomes clear in the framework of the three-particle
model. The three-particle model does not involve internal modes of the kinks,
but it gives a qualitative description to all the effects observed in the
three-soliton collisions, including the fractal scattering and the existence of
short-lived three-soliton bound states. The radiationless energy exchange
between the colliding solitons in weakly perturbed integrable systems takes
place in the vicinity of the separatrix multi-soliton solutions of the
corresponding integrable equations, where even small perturbations can result
in a considerable change in the collision outcome. This conclusion is
illustrated through the use of the reduced three-particle model.


title: Quantum Repeaters using Coherent-State Communication

abstract:
  We investigate quantum repeater protocols based upon atomic
qubit-entanglement distribution through optical coherent-state communication.
Various measurement schemes for an optical mode entangled with two spatially
separated atomic qubits are considered in order to nonlocally prepare
conditional two-qubit entangled states. In particular, generalized measurements
for unambiguous state discrimination enable one to completely eliminate
spin-flip errors in the resulting qubit states, as they would occur in a
homodyne-based scheme due to the finite overlap of the optical states in phase
space. As a result, by using weaker coherent states, high initial fidelities
can still be achieved for larger repeater spacing, at the expense of lower
entanglement generation rates. In this regime, the coherent-state-based
protocols start resembling single-photon-based repeater schemes.


title: Abel-Jacobi maps for hypersurfaces and non commutative Calabi-Yau's

abstract:
  It is well known that the Fano scheme of lines on a cubic 4-fold is a
symplectic variety. We generalize this fact by constructing a closed p-form
with p=2n-4 on the Fano scheme of lines on a (2n-2)-dimensional hypersurface Y
of degree n. We provide several definitions of this form - via the Abel-Jacobi
map, via Hochschild homology, and via the linkage class, and compute it
explicitly for n = 4. In the special case of a Pfaffian hypersurface Y we show
that the Fano scheme is birational to a certain moduli space of sheaves on a
p-dimensional Calabi--Yau variety X arising naturally in the context of
homological projective duality, and that the constructed form is induced by the
holomorphic volume form on X. This remains true for a general non Pfaffian
hypersurface but the dual Calabi-Yau becomes non commutative.


title: Distinguished trajectories in time dependent vector fields

abstract:
  We introduce a new definition of distinguished trajectory that generalises
the concepts of fixed point and periodic orbit to aperiodic dynamical systems.
This new definition is valid for identifying distinguished trajectories with
hyperbolic and non-hyperbolic types of stability. The definition is implemented
numerically and the procedure consist in determining a path of limit
coordinates. It has been successfully applied to known examples of
distinguished trajectories. In the context of highly aperiodic realistic flows
our definition characterises distinguished trajectories in finite time
intervals, and states that outside these intervals trajectories are no longer
distinguished.


title:
Utilisation des grammaires probabilistes dans les t\^aches de
  segmentation et d'annotation prosodique

abstract:
  Nous pr\'esentons dans cette contribution une approche \`a la fois symbolique
et probabiliste permettant d'extraire l'information sur la segmentation du
signal de parole \`a partir d'information prosodique. Nous utilisons pour ce
faire des grammaires probabilistes poss\'edant une structure hi\'erarchique
minimale. La phase de construction des grammaires ainsi que leur pouvoir de
pr\'ediction sont \'evalu\'es qualitativement ainsi que quantitativement.
  -----
  Methodologically oriented, the present work sketches an approach for prosodic
information retrieval and speech segmentation, based on both symbolic and
probabilistic information. We have recourse to probabilistic grammars, within
which we implement a minimal hierarchical structure. Both the stages of
probabilistic grammar building and its testing in prediction are explored and
quantitatively and qualitatively evaluated.


title:
Associated W and Higgs boson photoproduction and other electroweak
  photon induced processes at the LHC

abstract:
  Experimental prospects for studying at the LHC photon-proton interactions at
center of mass energies up to and above 1 TeV are discussed. Cross sections are
presented for many electroweak and beyond the Standard Model processes.
Selection strategies based on photon interaction tagging techniques are
discussed. Assuming a typical LHC multipurpose detector, the production of
single top associated to a W, and anomalous top signals and their irreducible
backgrounds are presented after applying detector acceptance cuts. The
associated photoproduction of Higgs and W bosons has a typical cross section of
20 fb. The possibility of observing this reaction is investigated for
topologies with signal-to-noise ratio close to unity.


title:
Nonlocal Landau theory of the magnetic phase diagram of highly
  frustrated magnetoelectric CuFeO$_2$

abstract:
  A nonlocal Landau-type free energy functional of the spin density is
developed to model the large variety of magnetic states which occur in the
magnetic field-temperature phase diagram of magnetoelectric CuFeO$_2$.
Competition among long-range quadratic exchange, biquadratic anti-symmetric
exchange, and trigonal anisotropy terms, consistent with the high-temperature
rhombohedral R$\bar{3}$m crystal symmetry, are shown to all play important
roles in stabilizing the unusual combination of commensurate and incommensurate
spin structures in this highly frustrated triangular antiferromagnet. It is
argued that strong magnetoelastic coupling is largely responsible for the
nonlocal nature of the free energy. A key feature of the analysis is that an
electric polarization is induced by a canting of the non-collinear
incommensurate spin structure. Application of the model to ordered spin states
in the triangular antiferromagnets MnBr$_2$ and NaFeO$_2$ is also discussed.


title: Associated primes of monomial ideals and odd holes in graphs

abstract:
  Let $G$ be a finite simple graph with edge ideal $I(G)$. Let $J(G)$ denote
the Alexander dual of $I(G)$. We show that a description of all induced cycles
of odd length in $G$ is encoded in the associated primes of $J(G)^2$. This
result forms the basis for a method to detect odd induced cycles of a graph via
ideal operations, e.g., intersections, products and colon operations. Moreover,
we get a simple algebraic criterion for determining whether a graph is perfect.
We also show how to determine the existence of odd holes in a graph from the
value of the arithmetic degree of $J(G)^2$.