title: Turbulence-condensate interaction in two dimensions

abstract:
  We present experimental results on turbulence generated in thin fluid layers
in the presence of a large-scale coherent flow, or a spectral condensate. It is
shown that the condensate modifies the third-order velocity moment in a much
wider interval of scales than the second one. The modification may include the
change of sign of the third moment in the inverse cascade. This observation may
help resolve a controversy on the energy flux in mesoscale atmospheric
turbulence (10-500 km): to recover a correct energy flux from the third
velocity moment one needs first to subtract the coherent flow. We find that the
condensate also increases the velocity flatness.


title: Magnetic Excitation in Artificially Designed Oxygen Molecule Magnet

abstract:
  We performed inelastic neutron scattering experiment to study magnetic
excitation of O$_2$ molecules adsorbed in microporous compound. The
dispersionless excitation with characteristic intensity modulation is observed
at $\hbar \omega = 7.8$ meV at low temperature. The neutron cross section is
explained by spin dimer model with intradimer distance of 3.1 \AA . Anomalous
behaviour in the temperature dependence is discussed in the context of enhanced
magnetoelasticity in the soft framework of O$_2$ molecule.


title: Geometric Entropy and Hagedorn/Deconfinement Transition

abstract:
  It has recently been proposed that the entanglement entropy can be an order
parameter of confinement/deconfinement transitions. To find a clear evidence,
we introduce a new quantity called the geometric entropy, which is related to
the entanglement entropy via a double Wick rotation. We analyze the geometric
entropy and manifestly show that its value becomes discontinuous at the
Hagedorn temperature both in the free N =4 super Yang-Mills and in its
supergravity dual.


title:
Classification and realizations of type III factor representations of
  Cuntz-Krieger algebras associated with quasi-free states

abstract:
  We completely classify type III factor representations of Cuntz-Krieger
algebras associated with quasi-free states up to unitary equivalence.
Furthermore, we realize these representations on concrete Hilbert spaces
without using GNS construction. Free groups and their type ${\rm II}_{1}$
factor representations are used in these realizations.


title:
Detection of continuous variable entanglement without coherent local
  oscillators

abstract:
  We propose three criteria for identifying continuous variable entanglement
between two many-particle systems with no restrictions on the quantum state of
the local oscillators used in the measurements. Mistakenly asserting a coherent
state for the local oscillator can lead to incorrectly identifying the presence
of entanglement. We demonstrate this in simulations with 100 particles, and
also find that large number fluctuations do not prevent the observation of
entanglement. Our results are important for quantum information experiments
with realistic Bose-Einstein condensates or in optics with arbitrary photon
states.


title: Algorithmic Based Fault Tolerance Applied to High Performance Computing

abstract:
  We present a new approach to fault tolerance for High Performance Computing
system. Our approach is based on a careful adaptation of the Algorithmic Based
Fault Tolerance technique (Huang and Abraham, 1984) to the need of parallel
distributed computation. We obtain a strongly scalable mechanism for fault
tolerance. We can also detect and correct errors (bit-flip) on the fly of a
computation. To assess the viability of our approach, we have developed a fault
tolerant matrix-matrix multiplication subroutine and we propose some models to
predict its running time. Our parallel fault-tolerant matrix-matrix
multiplication scores 1.4 TFLOPS on 484 processors (cluster jacquard.nersc.gov)
and returns a correct result while one process failure has happened. This
represents 65% of the machine peak efficiency and less than 12% overhead with
respect to the fastest failure-free implementation. We predict (and have
observed) that, as we increase the processor count, the overhead of the fault
tolerance drops significantly.


title:
Holographic Baryons : Static Properties and Form Factors from
  Gauge/String Duality

abstract:
  In this paper, we study properties of baryons by using a holographic dual of
QCD on the basis of the D4/D8-brane configuration, where baryons are described
by a soliton. We first determine the asymptotic behavior of the soliton
solution, which allows us to evaluate well-defined currents associated with the
U(N_f)_L \times U(N_f)_R chiral symmetry. Using the currents, we compute static
quantities of baryons such as charge radii and magnetic moments, and make a
quantitative test with experiments. It is emphasized that not only the nucleon
but also excited baryons, such as \Delta, N(1440), N(1535) etc., can be
analyzed systematically in this model. We also investigate the form factors and
find that our form factors agree well with the results that are
well-established empirically. With the form factors, the effective
baryon-baryon-meson cubic coupling constants among their infinite towers in the
model can be determined. Some physical implications following from these
results are discussed.


title: Elasticity of a polydisperse hard-sphere crystal

abstract:
  A general Monte Carlo simulation method of calculating the elastic constants
of polydisperse hard-sphere colloidal crystal was developed. The elastic
constants of a size polydisperse hard sphere fcc crystal is calculated. The
pressure and three elastic constants(C11, C12 and C44) increase significantly
with the polydispersity. It was also found from extrapolation that there is a
mechanical terminal polydispersity above which a fcc crystal will be
mechanically unstable.


title: Linear Covariant Gauges on the Lattice

abstract:
  Linear covariant gauges, such as Feynman gauge, are very useful in
perturbative calculations. Their nonperturbative formulation is, however,
highly non-trivial. In particular, it is a challenge to define linear covariant
gauges on a lattice. We consider a class of gauges in lattice gauge theory that
coincides with the perturbative definition of linear covariant gauges in the
formal continuum limit. The corresponding gauge-fixing procedure is described
and analyzed in detail, with an application to the pure SU(2) case. In
addition, results for the gluon propagator in the two-dimensional case are
given.


title: Real Space Coulomb Interaction: A Pairing Glue for FeAs Superconductors

abstract:
  In this paper we present a real space pairing glue for the iron-based layered
superconductors. It is shown that two static electrons embedded symmetrically
into two adjacent Fe plaquettes of the superconductor can be bounded due to the
Coulombic interaction. The pairing mechanism favors the existence of the
pseudogap in the underdoped FeAs superconductors. A criterion is introduced to
distinguish whether or not the pseudogap can open in a material.


title: Laws of the iterated logarithm for a class of iterated processes

abstract:
  Let $X=\{X(t), t\geq 0\}$ be a Brownian motion or a spectrally negative
stable process of index $1<\a<2$. Let $E=\{E(t),t\geq 0\}$ be the hitting time
of a stable subordinator of index $0<\beta<1$ independent of $X$. We use a
connection between $X(E(t))$ and the stable subordinator of index $\beta/\a$ to
derive information on the path behavior of $X(E_t)$. This is an extension of
the connection of iterated Brownian motion and (1/4)-stable subordinator due to
  Bertoin \cite{bertoin}.
  Using this connection, we obtain various laws of the iterated logarithm for
$X(E(t))$. In particular, we establish law of the iterated logarithm for local
time Brownian motion, $X(L(t))$, where $X$ is a Brownian motion (the case
$\a=2$) and $L(t)$ is the local time at zero of a stable process $Y$ of index
$1<\gamma\leq 2$ independent of $X$. In this case $E(\rho t)=L(t)$ with
$\beta=1-1/\gamma$ for some constant $\rho>0$. This establishes the lower bound
in the law of the iterated logarithm which we could not prove with the
techniques of our paper \cite{MNX}. We also obtain exact small ball probability
for $X(E_t)$ using ideas from \cite{aurzada}.


title: The anatomy of the NGC 5044 group - I. Group membership and dynamics

abstract:
  We use a combination of new AAOmega multi-object wide-field spectroscopic
observations and literature data to define 111 spectroscopically confirmed
members of the massive NGC 5044 group with M_B <= -13.5 mag, providing a
three-fold increase in group members over previous analyses of this group. We
find the group to have a dynamical mass of 9.2 x 10^13 solar masses, placing it
on the border between rich groups and poor clusters. However, comparison to the
L_x-sigma and L_x-mass relations shows it more closely follows cluster scaling
relations. Using a combination of crossing time, X-ray contours and
line-of-sight velocity profile we are able to preclude growth of the NGC 5044
group via major sub-group mergers within the last ~1 Gyr. While the majority of
dynamical indicators for the group suggest it is virialised, we find evidence
for a small, dynamically distinct sub-group at 1.4 Mpc from the group centre,
suggesting that the NGC 5044 group is the dominant structure in its local
environment, and is currently accreting smaller groups.


title: Strain and field modulation in bilayer graphene band structure

abstract:
  Using an external electric field, one can modulate the bandgap of Bernal
stacked bilayer graphene by breaking A-~B symmetry. We analyze strain effects
on the bilayer graphene using the extended Huckel theory and find that reduced
interlayer distance results in higher bandgap modulation, as expected.
Furthermore, above about 2.5 angstrom interlayer distance, the bandgap is
direct, follows a convex relation to electric field and saturates to a value
determined by the interlayer distance. However, below about 2.5 angstrom, the
bandgap is indirect, the trend becomes concave and a threshold electric field
is observed, which also depends on the stacking distance.


title: A self-synchronizing stream cipher based on chaotic coupled maps

abstract:
  A revised self-synchronizing stream cipher based on chaotic coupled maps is
proposed. This system adds input and output functions aim to strengthen its
security. The system performs basic floating-point analytical computation on
real numbers, incorporating auxiliarily with algebraic operations on integer
numbers.


title: Do quantum effects hold together DNA condensates?

abstract:
  The classical electrostatic interaction between DNA molecules in water in the
presence of counterions is reconsidered and we propose it is governed by a
modified Poisson-Boltzmann equation. Quantum fluctuations are then studied and
shown to lead to a vacuum interaction that is numerically computed for several
configurations of many DNA strands and found to be strongly many-body. This
Casimir vacuum interaction can be the ``glue'' holding together DNA molecules
into aggregates.


title:
On the uniqueness of promotion operators on tensor products of type A
  crystals

abstract:
  The affine Dynkin diagram of type $A_n^{(1)}$ has a cyclic symmetry. The
analogue of this Dynkin diagram automorphism on the level of crystals is called
a promotion operator. In this paper we show that the only irreducible type
$A_n$ crystals which admit a promotion operator are the highest weight crystals
indexed by rectangles. In addition we prove that on the tensor product of two
type $A_n$ crystals labeled by rectangles, there is a single connected
promotion operator. We conjecture this to be true for an arbitrary number of
tensor factors. Our results are in agreement with Kashiwara's conjecture that
all `good' affine crystals are tensor products of Kirillov-Reshetikhin
crystals.


title:
Real Scalar Field Scattering with Polynomial Approximation around
  Schwarzschild-de Sitter Black-hole

abstract:
  As one of the fitting methods, the polynomial approximation is effective to
process sophisticated problem. In this paper, we employ this approach to handle
the scattering of scalar field around the Schwarzschild-de Sitter black-hole.
The complex relationship between tortoise coordinate and radial coordinate is
replaced by the approximate polynomial. The Schr$\ddot{o}$dinger-like equation,
the real boundary conditions and the polynomial approximation construct a full
Sturm-Liouville type problem. Then this boundary value problem can be solved
numerically according to two limiting cases: the first one is the Nariai
black-hole whose horizons are close to each other, the second one is when the
horizons are widely separated. Compared with previous results (Brevik and
Tian), the field near the event horizon and cosmological horizon can have a
better description.


title: Shannon Meets Carnot: Mutual Information Via Thermodynamics

abstract:
  In this contribution, the Gaussian channel is represented as an equivalent
thermal system allowing to express its input-output mutual information in terms
of thermodynamic quantities. This thermodynamic description of the mutual
information is based upon a generalization of the $2^{nd}$ thermodynamic law
and provides an alternative proof to the Guo-Shamai-Verd\'{u} theorem, giving
an intriguing connection between this remarkable theorem and the most
fundamental laws of nature - the laws of thermodynamics.


title:
A comparison of formulations and solution methods for the Minimum-Envy
  Location Problem. Additional results

abstract:
  We consider a discrete facility location problem with a new form of equity
criterion. The model discussed in the paper analyzes the case where demand
points only have strict preference order on the sites where the plants can be
located. The goal is to find the location of the facilities minimizing the
total envy felt by the entire set of demand points. We define this new total
envy criterion and provide several integer linear programming formulations that
reflect and model this approach. Extensive computational tests are reported,
showing the potentials and limits of each formulation on several types of
instances.


title:
Aspects of Diffeomorphism and Conformal invariance in classical
  Liouville theory

abstract:
  The interplay between the diffeomorphism and conformal symmetries (a feature
common in quantum field theories) is shown to be exhibited for the case of
black holes in two dimensional classical Liouville theory. We show that
although the theory is conformally invariant in the near horizon limit, there
is a breaking of the diffeomorphism symmetry at the classical level. On the
other hand, in the region away from the horizon, the conformal symmetry of the
theory gets broken with the diffeomorphism symmetry remaining intact.


title: Factors Influencing the Earth's Magnetic Field Evolution

abstract:
  The relationship between the behavior of an ancient geomagnetic field
characteristics (paleointensity and frequency of inversions) and cyclic
recurrence of endogenic and cosmogeneous processes which are conceivably
connected with radial mantle heat transmission and the Earth rotation speed has
been studied. It is shown that endogenic processes affect the behavior of the
paleointensity and frequency of inversions. Large basalt effusions identified
with plumes are accompanied by the changes in paleointensity (by 30-40)% and
the frequency of inversions. Characteristic time intervals of paleointensity
variations caused by the formation of plumes makes up 10-20 Ma. The
paleointensity varies (by 15-30)% according to phases of the riftogenesis
activization and tension - compression cycles. The dependence of geomagnetic
field behavior on changes of the Earth rotation speed which occurred as a
result of the Earth - Moon - Sun system evolution has been analyzed. Thus, in
accordance with phases of the Earth - Moon distance changes (periodicity about
200 Ma) average values of the paleointensity varied by a factor of two.
Besides, the frequency of inversions, asymmetry of polarity and features of
paleointensity variations changed too.


title: Itinerant spin excitations near the hidden order transition in URu2Si2

abstract:
  By means of neutron scattering we show that the high-temperature precursor to
the hidden order state of the heavy fermion superconductor URu$_{2}$Si$_{2}$
exhibits heavily damped incommensurate paramagnons whose strong energy
dispersion is very similar to that of the long-lived longitudinal f-spin
excitations that appear below T$_{0}$. Since the underlying local f-exchange is
preserved we expect only the f-d interactions to change across the phase
transition and to cause the paramagnetic damping. The damping exhibits
single-ion behavior independent of wave vector and vanishes below the hidden
order transition. We suggest that this arises from a transition from valence
fluctuations to a hybridized f-d state below T$_{0}$. Here we present evidence
that the itinerant excitations, like those in chromium, are due to Fermi
surface nesting of hole and electron pockets so that the hidden order phase
likely originates from a Fermi-surface instability. We identify wave vectors
that span nested regions of a band calculation and that match the neutron spin
crossover from incommensurate to commensurate on approach to the hidden order
phase.


title: Geometric quantization for proper actions

abstract:
  We first introduce an invariant index for G-equivariant elliptic differential
operators on a locally compact manifold M admitting a proper cocompact action
of a locally compact group G. It generalizes the Kawasaki index for orbifolds
to the case of proper cocompact actions. Our invariant index is used to show
that an analog of the Guillemin-Sternberg geometric quantization conjecture
holds if M is symplectic with a Hamiltonian action of G that is proper and
cocompact. This essentially solves a conjecture of Hochs and Landsman.


title:
Possible unconventional superconductivity in iron-based layered compound
  LaFePO: Study of heat capacity

abstract:
  Heat capacity measurements were performed on recently discovered iron based
layered superconductors, non doped LaFePO and fluorine doped LaFePO. A
relatively large electronic heat capacity coefficient and a small normalized
heat capacity jump at Tc = 3.3 K were observed in LaFePO. LaFePO0.94F0.06 had a
smaller electronic heat capacity coefficient and a larger normalized heat
capacity jump at Tc = 5.8 K. These values indicate that these compounds have
strong electron electron correlation and magnetic spin fluctuation, which are
the signatures of unconventional superconductivity mediated by spin
fluctuation.


title:
Possible contributions to $e^+e^- \to J/\psi + \eta_c$ due to
  intermediate meson rescatterings

abstract:
  Inspired by the obvious discrepancies between experiment and non-relativistic
QCD (NRQCD) studies of $e^+ e^-\to J/\psi+\eta_c$ at $\sqrt{s}\simeq 10.6$ GeV,
we investigate contributions from intermediate meson loops as long-range
interaction transitions to this process. The intermediate meson loops include
$D\bar D(\bar D^\ast)$, $D\bar D^\ast(D {or} D^\ast)$, $D^\ast \bar D^\ast(D)$
and corresponding $D_s$ intermediate mesons. With the constraints from
experimental data on the vertex couplings, we find that the intermediate meson
loops account for $2.7\sim 6.7 fb$ of the cross sections within a reasonable
range of cut-off energies of the factor parameter. We also investigate
contributions from the absorptive part and find that it accounts for
approximately $0.58\sim 1.38 fb$. These results imply that contributions from
long-range interaction transitions may still play a role in such an energy
region.


title: On De Giorgi Conjecture in Dimension $N \geq 9$

abstract:
  A celebrated conjecture due to De Giorgi states that any bounded solution of
the equation $\Delta u + (1-u^2) u = 0 \hbox{in} \R^N $ with $\pp_{y_N}u >0$
must be such that its level sets $\{u=\la\}$ are all hyperplanes, {\em \bf at
least} for dimension $N\le 8$. A counterexample for $N\ge 9$ has long been
believed to exist. Based on a minimal graph $\Gamma$ which is not a hyperplane,
found by Bombieri, De Giorgi and Giusti in $\R^N$, $N\ge 9$, we prove that for
any small $\alpha >0$ there is a bounded solution $u_\alpha(y)$ with
$\pp_{y_N}u_\alpha >0$, which resembles $ \tanh (\frac t{\sqrt{2}}) $, where
$t=t(y)$ denotes a choice of signed distance to the blown-up minimal graph
$\Gamma_\alpha := \alpha^{-1}\Gamma$. This solution constitutes a
counterexample to De Giorgi conjecture for $N\ge 9$.


title: Casimir interaction of dielectric gratings

abstract:
  We derive an exact solution for the Casimir force between two arbitrary
periodic dielectric gratings and illustrate our method by applying it to two
nanostructured silicon gratings. We also reproduce the Casimir force gradient
measured recently [1] between a silicon grating and a gold sphere taking into
account the material dependence of the force. We find good agreement between
our theoretical results and the measured values both in absolute force values
and the ratios between the exact force and PFA predictions.


title: Evolution of fragmented states

abstract:
  We consider the problem of evolution of the many-body state of a weakly
interacting system of bosons in an initially fragmented (Fock) state. We show
that the state at any time can be expressed as a continuous superposition of an
infinite number of Gross-Pitaevskii states.


title: On the Classification of Darboux Integrable Chains

abstract:
  We study differential-difference equation of the form
$t_{x}(n+1)=f(t(n),t(n+1),t_x(n))$ with unknown $t=t(n,x)$ depending on $x$,
$n$. The equation is called Darboux integrable, if there exist functions $F$
(called an $x$-integral) and $I$ (called an $n$-integral), both of a finite
number of variables $x$, $t(n)$, $t(n\pm 1)$, $t(n\pm 2)$, $...$, $t_x(n)$,
$t_{xx}(n)$, $...$, such that $D_xF=0$ and $DI=I$, where $D_x$ is the operator
of total differentiation with respect to $x$, and $D$ is the shift operator:
$Dp(n)=p(n+1)$. The Darboux integrability property is reformulated in terms of
characteristic Lie algebras that gives an effective tool for classification of
integrable equations. The complete list of equations of the form above
admitting nontrivial $x$-integrals is given in the case when the function $f$
is of the special form $f(x,y,z)=z+d(x,y)$.


title: Operator quantum error correction for continuous dynamics

abstract:
  We study the conditions under which a subsystem code is correctable in the
presence of noise that results from continuous dynamics. We consider the case
of Markovian dynamics as well as the general case of Hamiltonian dynamics of
the system and the environment, and derive necessary and sufficient conditions
on the Lindbladian and system-environment Hamiltonian, respectively. For the
case when the encoded information is correctable during an entire time
interval, the conditions we obtain can be thought of as generalizations of the
previously derived conditions for decoherence-free subsystems to the case where
the subsystem is time dependent. As a special case, we consider conditions for
unitary correctability. In the case of Hamiltonian evolution, the conditions
for unitary correctability concern only the effect of the Hamiltonian on the
system, whereas the conditions for general correctability concern the entire
system-environment Hamiltonian. We also derive conditions on the Hamiltonian
which depend on the initial state of the environment, as well as conditions for
correctability at only a particular moment of time. We discuss possible
implications of our results for approximate quantum error correction.


title: Natural Numbers and Quantum States in Fock Space

abstract:
  We investigate the expression of natural numbers in any base from a quantum
point of view. In particular, resorting to the one-to-one correspondence
between natural numbers and Fock states, we construct a set of multiboson
operators and a set of translation operators, whose action on the Fock states
leads to the coefficients identifying a natural number in any base.


title: The EDELWEISS-II experiment

abstract:
  EDELWEISS is a direct dark matter search situated in the low radioactivity
environment of the Modane Underground Laboratory. The experiment uses Ge
detectors at very low temperature in order to identify eventual rare nuclear
recoils induced by elastic scattering of WIMPs from our Galactic halo. The
commissioning of the second phase of the experiment, involving more than 7 kg
of Ge, has been completed in 2007. Two new type of detectors with active
rejection of events due to surface contamination have demonstrated the
performances required to achieve the physics goal of the present phase.


title: Measurement-induced entanglement of two superconducting qubits

abstract:
  We study the problem of two superconducting quantum qubits coupled via a
resonator. If only one quanta is present in the system and the number of
photons in the resonator is measured with a null result, the qubits end up in
an entangled Bell state. Here we look at one source of errors in this quantum
nondemolition scheme due to the presence of more than one quanta in the
resonator, previous to the measurement. By analyzing the structure of the
conditional Hamiltonian with arbitrary number of quanta, we show that the
scheme is remarkably robust against these type of errors.


title:
Microwave Penetration Depth and Quasiparticle Conductivity in
  PrFeAsO_1-y Single Crystals : Evidence for a Full-Gap Superconductor

abstract:
  In-plane microwave penetration depth $\lambda_{ab}$ and quaiparticle
conductivity at 28 GHz are measured in underdoped single crystals of the
Fe-based superconductor PrFeAsO$_{1-y}$ ($T_c\approx 35$ K) by using a
sensitive superconducting cavity resonator. $\lambda_{ab}(T)$ shows flat
dependence at low temperatures, which is incompatible with the presence of
nodes in the superconducting gap $\Delta({\bf k})$. The temperature dependence
of the superfluid density demonstrates that the gap is non-zero
($\Delta/k_BT_c\gtrsim 1.6$) all over the Fermi surface. The microwave
conductivity below $T_c$ exhibits an enhancement larger than the coherence
peak, reminiscent of high-$T_c$ cuprate superconductors.


title: Energy scattering for 2D critical wave equation

abstract:
  We investigate existence and asymptotic completeness of the wave operators
for nonlinear Klein-Gordon and Schr\"odinger equations with a defocusing
exponential nonlinearity in two space dimensions. A certain threshold is
defined based on the value of the conserved Hamiltonian, below which the
exponential potential energy is dominated by the kinetic energy via a
Trudinger-Moser type inequality.
  We prove that if the energy is below or equal to the critical value, then the
solution approaches a free Klein-Gordon solution at the time infinity. The
interesting feature in the critical case is that the Strichartz estimate
together with Sobolev-type inequalities can not control the nonlinear term
uniformly on each time interval, but with constants depending on how much the
solution is concentrated. Thus we have to trace concentration of the energy
along time, in order to set up favorable nonlinear estimates, and then to
implement Bourgain's induction argument. We show the same result for the
"subcritical" nonlinear Schr\"odinger equation.


title:
Entropy driven mechanism for noise induced patterns formation in
  reaction-diffusion systems

abstract:
  We have studied the entropy-driven mechanism leading to stationary patterns
formation in stochastic systems with local dynamics and non-Fickian diffusion.
We have shown that a multiplicative noise fulfilling a fluctuation-dissipation
relation is able to induce and sustain stationary structures with its intensity
growth. It was found that at small and large noise intensities the system is
characterized by unstable homogeneous states. At intermediate values of the
noise intensity three types of patterns are possible: nucleation, spinodal
decomposition and stripes with liner defects (dislocations). Our analytical
investigations are verified by computer simulations.


title:
TRANS-Net: an Efficient Peer-to-Peer Overlay Network Based on a Full
  Transposition Graph

abstract:
  In this paper we propose a new practical P2P system based on a full
transposition network topology named TRANS-Net. Full transposition networks
achieve higher fault-tolerance and lower congestion among the class of
transposition networks. TRANS-Net provides an efficient lookup service i.e. k
hops with high probability, where k satisfies Theta(log_n m) less than k less
than Theta(log_2 m), where m denotes the number of system nodes and n is a
system parameter related to the maximum number that m can take (up to n!).
Experiments show that the look-up performance achieves the lower limit of the
complexity relation. TRANS-Net also preserves data locality and provides
efficient look-up performance for complex queries such as multi-dimensional
queries.


title: Vectors, Cyclic Submodules and Projective Spaces Linked with Ternions

abstract:
  Given a ring of ternions $R$, i. e., a ring isomorphic to that of upper
triangular $2\times 2$ matrices with entries from an arbitrary commutative
field $F$, a complete classification is performed of the vectors from the free
left $R$-module $R^{n+1}$, $n \geq 1$, and of the cyclic submodules generated
by these vectors. The vectors fall into $5 + |F|$ and the submodules into 6
distinct orbits under the action of the general linear group $\GL_{n+1}(R)$.
  Particular attention is paid to {\it free} cyclic submodules generated by
\emph{non}-unimodular vectors, as these are linked with the lines of
$\PG(n,F)$, the $n$-dimensional projective space over $F$. In the finite case,
$F$ = $\GF(q)$, explicit formulas are derived for both the total number of
non-unimodular free cyclic submodules and the number of such submodules passing
through a given vector. These formulas yield a combinatorial approach to the
lines and points of $\PG(n,q)$, $n\geq 2$, in terms of vectors and
non-unimodular free cyclic submodules of $R^{n+1}$.

categories: math-ph math.AG math.MP math.RA quant-ph


title:
An Ab Initio Study on Energy Gap of Bilayer Graphene Nanoribbons with
  Armchair Edges

abstract:
  Dependency of energy bandgap (Eg) of bilayer armchair graphene nanoribbons
(AGNRB) on their widths, interlayer distance (D) and edge doping concentration
of boron/nitrogen is investigated using local density approximation and compare
to the results of monolayer graphene nanoribbons (AGNRM). Although Eg of AGNRB,
in general, is smaller than that of AGNRM, AGNRB exhibits two distinct groups,
metal and semiconductor, while AGNRM displays purely semiconducting behavior.
Eg of AGNRB, moreover, is highly sensitive to D, indicating a possible
application in tuning Eg by varying D. Finally, edge doping of both AGNR
systems reduces Eg by 11-17%/4-10% for AGNRM/AGNRB, respectively.


title:
Periodic and Solitary Travelling-Wave Solutions of an Extended Reduced
  Ostrovsky Equation

abstract:
  Periodic and solitary travelling-wave solutions of an extended reduced
Ostrovsky equation are investigated. Attention is restricted to solutions that,
for the appropriate choice of certain constant parameters, reduce to solutions
of the reduced Ostrovsky equation. It is shown how the nature of the waves may
be categorized in a simple way by considering the value of a certain single
combination of constant parameters. The periodic waves may be smooth humps,
cuspons, loops or parabolic corner waves. The latter are shown to be the
maximum-amplitude limit of a one-parameter family of periodic smooth-hump
waves. The solitary waves may be a smooth hump, a cuspon, a loop or a parabolic
wave with compact support. All the solutions are expressed in parametric form.
Only in one circumstance can the variable parameter be eliminated to give a
solution in explicit form. In this case the resulting waves are either a
solitary parabolic wave with compact support or the corresponding periodic
corner waves.


title:
alpha_s and the tau hadronic width: fixed-order, contour-improved and
  higher-order perturbation theory

abstract:
  The determination of $\alpha_s$ from hadronic $\tau$ decays is revisited,
with a special emphasis on the question of higher-order perturbative
corrections and different possibilities of resumming the perturbative series
with the renormalisation group: fixed-order (FOPT) vs. contour-improved
perturbation theory (CIPT). The difference between these approaches has evolved
into a systematic effect that does not go away as higher orders in the
perturbative expansion are added. We attempt to clarify under which
circumstances one or the other approach provides a better approximation to the
true result. To this end, we propose to describe the Adler function series by a
model that includes the exactly known coefficients and theoretical constraints
on the large-order behaviour originating from the operator product expansion
and the renormalisation group. Within this framework we find that while CIPT is
unable to account for the fully resummed series, FOPT smoothly approaches the
Borel sum, before the expected divergent behaviour sets in at even higher
orders. Employing FOPT up to the fifth order to determine $\alpha_s$ in the
$\MSb$ scheme, we obtain $\alpha_s(M_\tau)=0.320 {}^{+0.012}_{-0.007}$,
corresponding to $\alpha_s(M_Z) = 0.1185 {}^{+0.0014}_{-0.0009}$. Improving
this result by including yet higher orders from our model yields
$\alpha_s(M_\tau)=0.316 \pm 0.006$, which after evolution leads to
$\alpha_s(M_Z) = 0.1180 \pm 0.0008$. Our results are lower than previous values
obtained from $\tau$ decays.


title: The Photon and Magnetic Monopoles

abstract:
  The Energy-Length Rule implies the following properties for a transversal
isolated system : on one side energy multiplied with zero component of x = both
sign of ch, on the other side the sine of the p perpendicular to x,
representing the helicity of the photon, is positive and negative. It
corresponds to the sign of zero component of x, referring to the two cones
which define respectively system and antisystem. The energy is obviously
positive for both of them. Keeping p orthogonal to x implies right and left
handed circular polarization simultaneously .Then in our interpretation the
isolated real photon hides what we call the two monopoles. They are manifested
in the real polarized photons being independent but united through their root
as system and antisystem.


title: Quantum field thermalization in expanding backgrounds

abstract:
  The 2PI effective action formalism for quantum fields out of equilibrium is
set up in an expanding (Friedmann-Robertson-Walker) background. We write down
and solve the evolution equations for a phi^4 model at NLO in a coupling
expansion. We comment on issues of renormalization, lattice discretization and
the range of applicability of the approach. A number of example calculations
are presented, including thermalization and (p)reheating. Generalizations to
more complicated systems and applications are discussed.


title:
Structural properties, defects and structural phase transition in the
  ROFeM (R=La, Nd; M=As, P) materials

abstract:
  The structural properties of the ROFeM (R=La, Nd; M=As, P) materials have
been analyzed by means of electron diffraction, high-resolution
transmission-electron microscopy (TEM) and in-situ cooling TEM observations.
The experimental results demonstrate that the layered ROFeM crystals often
contain a variety of structural defects, such as stacking faults and
small-angle boundaries. The in-situ TEM investigations reveal that, in
association with the remarkable spin-density-wave (SDW) instability near 150 K,
complex structural transitions can be clearly observed in both crystal symmetry
and local microstructure features.


title: Computation of a Feynman integral

abstract: A Feymnan integral is computed exactly using LLL


title:
Competition between antiferromagnetism and superconductivity,
  electron-hole doping asymmetry and "Fermi Surface" topology in cuprates

abstract:
  We investigate the asymmetry between electron and hole doping in a 2D Mott
insulator, and the resulting competition between antiferromagnetism (AF) and
d-wave superconductivity (SC), using variational Monte Carlo for projected wave
functions. We find that key features of the T = 0 phase diagram, such as
critical doping for SC-AF coexistence and the maximum value of the SC order
parameter, are determined by a single parameter which characterises the
topology of the "Fermi surface" at half filling defined by the bare
tight-binding parameters. Our results give insight into why AF wins for
electron doping, while SC is dominant on the hole doped side. We also suggest
using band structure engineering to control the parameter for enhancing SC.


title:
Flux dependent 1.5 MeV self-ion beam induced sputtering from Gold
  nanostructured thin films

abstract:
  We discuss four important aspects of 1.5 MeV Au2+ ion-induced flux dependent
sputtering from gold nanostrcutures (of an average size 7.6 nm and height 6.9
nm) that are deposited on silicon substrates: (a) Au sputtering yield at the
ion flux of 6.3x10^12 ions cm-2 s-1 is found to be 312 atoms/ion which is about
five times the sputtering yield reported earlier under identical irradiation
conditions at a lower beam flux of 10^9 ions cm-2 s-1, (b) the sputtered yield
increases with increasing flux at lower fluence and reduces at higher fluence
(1.0x10^15 ions cm-2) for nanostructured thin films while the sputtering yield
increases with increasing flux and fluence for thick films (27.5 nm Au
deposited on Si) (c) Size distribution of sputtered particles has been found to
vary with the incident beam flux showing a bimodal distribution at higher flux
and (d) the decay exponent obtained from the size distributions of sputtered
particles showed an inverse power law dependence ranging from 1.5 to 2.5 as a
function of incident beam flux. The exponent values have been compared with
existing theoretical models to understand the underlying mechanism. The role of
wafer temperature associated with the beam flux has been invoked for a
qualitative understanding of the sputtering results in both the nanostructured
thin films and thick films.


title:
Asymptotics of the number of partitions into p-cores and some
  trigonometric sums

abstract:
  An asymptotic formula for the number of partitions into p-cores is derived.
As a byproduct some integer valued trigonometric sums are found


title: Analysis of quantum semigroups with GKS--Lindblad generators II. General

abstract:
  Semigroups describing the time evolution of open quantum systems in
finite-dimensional spaces have generators of a special form, known as Lindblad
generators. These generators and the corresponding processes of time evolution
are analyzed, characterized as Decay, Dissipation and Dephasing. In relation to
these processes the Hilbert space of the system is equipped with a special
structure, a decomposition into a sum of mutually orthogonal subspaces. The
complete set of all the stationary states and the asymptotic behavior of the
evolutions are presented in detail. Some unusual special facts about invariant
operators and symmetries are studied, examples are demonstrated. Perturbation
theory for the structure and for the stationary states is discussed and
performed in case studies.


title: Hydrodynamics of spacetime and vacuum viscosity

abstract:
  It has recently been shown that the Einstein equation can be derived by
demanding a non-equilibrium entropy balance law dS = dQ/T + dS_i hold for all
local acceleration horizons through each point in spacetime. The entropy change
dS is proportional to the change in horizon area while dQ and T are the energy
flux across the horizon and Unruh temperature seen by an accelerating observer
just inside the horizon. The internal entropy production term dS_i is
proportional to the squared shear of the horizon and the ratio of the
proportionality constant to the area entropy density is \hbar/4\pi. Here we
will show that this derivation can be reformulated in the language of
hydrodynamics. We postulate that the vacuum thermal state in the Rindler wedge
of spacetime obeys the holographic principle. Hydrodynamic perturbations of
this state exist and are manifested in the dynamics of a stretched horizon
fluid at the horizon boundary. Using the equations of hydrodynamics we derive
the entropy balance law and show the Einstein equation is a consequence of
vacuum hydrodynamics. This result implies that \hbar/4\pi is the shear
viscosity to entropy density ratio of the local vacuum thermal state. The value
\hbar/4\pi has attracted much attention as the shear viscosity to entropy
density ratio for all gauge theories with an Einstein gravity dual. It has also
been conjectured as the universal lower bound on the ratio. We argue that our
picture of the vacuum thermal state is consistent with the physics of the
gauge/gravity dualities and then consider possible applications to open
questions.


title:
Spin and orbital angular momentum in gauge theories: Nucleon spin
  structure and multipole radiation revisited

abstract:
  We address and solve the long-standing gauge-invariance problem of the
nucleon spin structure. Explicitly gauge-invariant spin and orbital angular
momentum operators of quarks and gluons are obtained. This was previously
thought to be an impossible task, and opens a more promising avenue towards the
understanding of the nucleon spin. Our research also justifies the traditional
use of the canonical, gauge-dependent angular momentum operators of photons and
electrons in the multipole-radiation analysis and labeling of atomic states;
and sheds much light on the related energy-momentum problem in gauge theories,
especially in connection with the nucleon momentum.


title:
Making Maps from Planck LFI 30GHz Data with Asymmetric Beams and Cooler
  Noise

abstract:
  The Planck satellite will observe the full sky at nine frequencies from 30 to
857 GHz. The goal of this paper is to examine the effects of four realistic
instrument systematics in the 30 GHz frequency maps: non-axially-symmetric
beams, sample integration, sorption cooler noise, and pointing errors. We
simulated one year long observations of four 30 GHz detectors. The simulated
timestreams contained CMB, foreground components (both galactic and
extra-galactic), instrument noise (correlated and white), and the four
instrument systematic effects. We made maps from the timelines and examined the
magnitudes of the systematics effects in the maps and their angular power
spectra. We also compared the maps of different mapmaking codes to see how they
performed. We used five mapmaking codes (two destripers and three optimal
codes). None of our mapmaking codes makes an attempt to deconvolve the beam
from its output map. Therefore all our maps had similar smoothing due to beams
and sample integration. Temperature to polarization cross-coupling due to beam
mismatch causes a detectable bias in the TE spectrum of the CMB map. The
effects of cooler noise and pointing errors did not appear to be major concerns
for the 30 GHz channel. The only essential difference found so far between
mapmaking codes that affects accuracy (in terms of residual RMS) is baseline
length. All optimal codes give essentially indistinguishable results. A
destriper gives the same result as the optimal codes when the baseline is set
short enough. For longer baselines destripers require less computing resources
but deliver a noisier map.


title: Colloidal suspensions in modulated light fields

abstract:
  Periodically-modulated potentials in the form of light fields have previously
been applied to induce reversible phase transitions in dilute colloidal systems
with long-range interactions. Here we investigate whether similar transitions
can be induced in very dense systems, where inter-particle contacts are
important. Using microscopy we show that particles in such systems are indeed
strongly affected by modulated potentials. We discuss technical aspects
relevant to generating the light-induced potentials and to imaging
simultaneously the particles. We also consider what happens when the particle
size is comparable with the modulation wavelength. The effects of selected
modulation wavelengths as well as pure radiation pressure are illustrated.


title: Complete Einstein metrics are geodesically rigid

abstract:
  We prove that every complete Einstein (Riemannian or pseudo-Riemannian)
metric $g$ is geodesically rigid: if any other complete metric $\bar g$ has the
same (unparametrized) geodesics with $g$, then the Levi-Civita connections of
$g$ and $\bar g$ coincide.


title: Wave function derivation of the JIMWLK equation

abstract:
  Using the stationary lightcone perturbation theory, we propose the complete
and careful derivation the JIMWLK equation. We show that the rigorous treatment
requires the knowledge of a boosted wave function with second order accuracy.
Previous wave function approaches are incomplete and implicitly used the time
ordered perturbation theory, which requires a usage of an external target
field.


title:
Fractional derivatives of random walks: Time series with long-time
  memory

abstract:
  We review statistical properties of models generated by the application of a
(positive and negative order) fractional derivative operator to a standard
random walk and show that the resulting stochastic walks display
slowly-decaying autocorrelation functions. The relation between these
correlated walks and the well-known fractionally integrated autoregressive
(FIGARCH) models, commonly used in econometric studies, is discussed. The
application of correlated random walks to simulate empirical financial times
series is considered and compared with the predictions from FIGARCH and the
simpler FIARCH processes. A comparison with empirical data is performed.


title: Enhancement of CO detection in Al doped graphene

abstract:
  A principle of enhancement CO adsorption was developed theoretically by using
density functional theory through doping Al into graphene. The results show
that the Al doped graphene has strong chemisorption of CO molecule by forming
Al-CO bond, where CO onto intrinsic graphene remains weak physisorption.
Furthermore, the enhancement of CO sensitivity in the Al doped graphene is
determined by a large electrical conductivity change after adsorption, where CO
absorption leads to increase of electrical conductivity upon via introducing
large amount of shallow acceptor states. Therefore, this newly developed Al
doped graphene would be an excellent candidate for sensing CO gas.


title:
Constraints on scalar diffusion anomaly in three-dimensional flows
  having bounded velocity gradients

abstract:
  This study is concerned with the decay behaviour of a passive scalar $\theta$
in three-dimensional flows having bounded velocity gradients. Given an
initially smooth scalar distribution, the decay rate $d<\theta^2>/dt$ of the
scalar variance $<\theta^2>$ is found to be bounded in terms of controlled
physical parameters. Furthermore, in the zero diffusivity limit, $\kappa\to0$,
this rate vanishes as $\kappa^{\alpha_0}$ if there exists an $\alpha_0\in(0,1]$
independent of $\kappa$ such that $<|(-\Delta)^{\alpha/2}\theta|^2><\infty$ for
$\alpha\le\alpha_0$. This condition is satisfied if in the limit $\kappa\to0$,
the variance spectrum $\Theta(k)$ remains steeper than $k^{-1}$ for large wave
numbers $k$. When no such positive $\alpha_0$ exists, the scalar field may be
said to become virtually singular. A plausible scenario consistent with
Batchelor's theory is that $\Theta(k)$ becomes increasingly shallower for
smaller $\kappa$, approaching the Batchelor scaling $k^{-1}$ in the limit
$\kappa\to0$. For this classical case, the decay rate also vanishes, albeit
more slowly -- like $(\ln P_r)^{-1}$, where $P_r$ is the Prandtl or Schmidt
number. Hence, diffusion anomaly is ruled out for a broad range of scalar
distribution, including power-law spectra no shallower than $k^{-1}$. The
implication is that in order to have a $\kappa$-independent and non-vanishing
decay rate, the variance at small scales must necessarily be greater than that
allowed by the Batchelor spectrum. These results are discussed in the light of
existing literature on the asymptotic exponential decay $<\theta^2>\sim
e^{-\gamma t}$, where $\gamma>0$ is independent of $\kappa$.


title: Constituent gluon interpretation of glueballs and gluelumps

abstract:
  Arguments are given that support the interpretation of the lattice QCD
glueball and gluelump spectra in terms of bound states of massless constituent
gluons with helicity-1. In this scheme, the mass hierarchy of the currently
known gluelumps and glueballs is mainly due to the number of constituent gluons
and can be understood within a simple flux tube model. It is also argued that
the lattice QCD $0^{+-}$ glueball should be seen as a four-gluon bound state.
The flux tube model allows for a parameter-free computation of its mass, which
is in good agreement with lattice QCD.


title: Lower Bounds for Boxicity

abstract:
  An axis-parallel $b$-dimensional box is a Cartesian product $R_1\times
R_2\times...\times R_b$ where $R_i$ is a closed interval of the form
$[a_i,b_i]$ on the real line. For a graph $G$, its \emph{boxicity} box(G) is
the minimum dimension $b$, such that $G$ is representable as the intersection
graph of boxes in $b$-dimensional space. Although boxicity was introduced in
1969 and studied extensively, there are no significant results on lower bounds
for boxicity. In this paper, we develop two general methods for deriving lower
bounds. Applying these methods we give several results, some of which are
listed below:
  (1) The boxicity of a graph on $n$ vertices with no universal vertices and
minimum degree $\delta$ is at least $n/2(n-\delta-1)$. (2) Consider the
$\mathcal{G}(n,p)$ model of random graphs. Let $ p \le 1- \frac{40 \log
n}{n^2}$. Then, for $G \in \mathcal{G}(n,p)$, almost surely
$box(G)=\Omega(np(1-p))$. On setting $p=1/2$ we immediately infer that almost
all graphs have boxicity $\Omega(n)$. (3) Spectral lower bounds for the
boxicity of $k$-regular graphs. (4) The boxicity of random $k$-regular graphs
on $n$ vertices (where $k$ is fixed) is $\Omega(k/\log k)$. (5) There exists a
positive constant$c$ such that almost all balanced bipartite graphs on $2n$
vertices with exactly $m$ edges have boxicity at least $c m/n$, for $ m\le c'
n^2/3$ for any positive constant $c' < 1$.


title: 'Binge' drinking in the UK: a social network phenomenon

abstract:
  We analyse the recent rapid growth of 'binge' drinking in the UK. This means
the consumption of large amounts of alcohol, especially by young people,
leading to serious anti-social and criminal behaviour in urban centres. We show
how a simple agent-based model, based on binary choice with externalities,
combined with a small amount of survey data can explain the phenomenon. We show
that the increase in binge drinking is a fashion-related phenomenon, with
imitative behaviour spreading across socila networks The results show that a
small world network, rather than a random or scale free, offers the best
description of the key aspects of the data


title: Noncommutative resolutions of ADE fibered Calabi-Yau threefolds

abstract:
  In this paper we construct noncommutative resolutions of a certain class of
Calabi-Yau threefolds studied by F. Cachazo, S. Katz and C. Vafa. The
threefolds under consideration are fibered over a complex plane with the fibers
being deformed Kleinian singularities. The construction is in terms of a
noncommutative algebra introduced by V. Ginzburg, which we call the "N=1 ADE
quiver algebra".


title:
Critical evaluation of the computational methods used in the forced
  polymer translocation

abstract:
  In forced polymer translocation, the average translocation time, $\tau$,
scales with respect to pore force, $f$, and polymer length, $N$, as $\tau \sim
f^{-1} N^{\beta}$. We demonstrate that an artifact in Metropolis Monte Carlo
method resulting in breakage of the force scaling with large $f$ may be
responsible for some of the controversies between different computationally
obtained results and also between computational and experimental results. Using
Langevin dynamics simulations we show that the scaling exponent $\beta \le 1 +
\nu$ is not universal, but depends on $f$. Moreover, we show that forced
translocation can be described by a relatively simple force balance argument
and $\beta$ to arise solely from the initial polymer configuration.


title:
Method for finding the critical temperature of the island in a SET
  structure

abstract:
  We present a method to measure the critical temperature of the island of a
superconducting single electron transistor. The method is based on a sharp
change in the slope of the zero-bias conductance as a function of temperature.
We have used this method to determine the superconducting phase transition
temperature of the Nb island of an superconducting single electron transistor
with Al leads. We obtain $T_\mathrm{c}^\mathrm{Nb}$ as high as 8.5 K and gap
energies up to $\Delta_\mathrm{Nb}\simeq 1.45$ meV. By looking at the zero bias
conductance as a function of magnetic field instead of temperature, also the
critical field of the island can be determined. Using the orthodox theory, we
have performed extensive numerical simulations of charge transport properties
in the SET at temperatures comparable to the gap, which match very well the
data, therefore providing a solid theoretical basis for our method.


title:
Directionally Convex Ordering of Random Measures, Shot Noise Fields and
  Some Applications to Wireless Communications

abstract:
  Directionally convex ($dcx$) ordering is a tool for comparison of dependence
structure of random vectors that also takes into account the variability of the
marginal distributions. When extended to random fields it concerns comparison
of all finite dimensional distributions. Viewing locally finite measures as
non-negative fields of measure-values indexed by the bounded Borel subsets of
the space, in this paper we formulate and study the $dcx$ ordering of random
measures on locally compact spaces. We show that the $dcx$ order is preserved
under some of the natural operations considered on random measures and point
processes, such as deterministic displacement of points, independent
superposition and thinning as well as independent, identically distributed
marking. Further operations such as position dependent marking and displacement
of points though do not preserve the $dcx$ order on all point processes, are
shown to preserve the order on Cox point processes. We also examine the impact
of $dcx$ order on the second moment properties, in particular on clustering and
on Palm distributions. Comparisons of Ripley's functions, pair correlation
functions as well as examples seem to indicate that point processes higher in
$dcx$ order cluster more. As the main result, we show that non-negative
integral shot-noise fields with respect to $dcx$ ordered random measures
inherit this ordering from the measures. Numerous applications of this result
are shown, in particular to comparison of various Cox processes and some
performance measures of wireless networks, in both of which shot-noise fields
appear as key ingredients. We also mention a few pertinent open questions.


title:
Electron drift velocity control in GaAs-in-Al2O3 quantum wire transistor
  structure due to the electron scattering rate alteration

abstract:
  Electron transport in the transistor structure based on thin undoped
GaAs-in-Al2O3 quantum wire is simulated by ensemble Monte-Carlo method taking
into account electron scattering by the phonons and surface roughness. The
influence of surface roughness height on electron drift velocity at 77 and 300
K is investigated for the values of longitudinal electric field strength of 0.1
and 1.0 kV/cm. A possibility of electron drift velocity control due to
variation of the bias applied to the gates, which results in the electron
scattering rate alteration, is ascertained.


title: Dynamics of Non Classically Reproducible Entanglement

abstract:
  We investigate when the quantum correlations of a bipartite system, under the
influence of environments with memory, are not reproducible with certainty by a
classical local hidden variable model. To this purpose, we compare the dynamics
of a Bell inequality with that of entanglement, as measured by concurrence. We
find time regions when Bell inequality is not violated even in correspondence
to high values of concurrence (up to $\approx 0.8$). We also suggest that these
results may be observed by adopting a modification of a recent experimental
optical setup. These findings indicate that even highly entangled systems
cannot be exploited with certainty in contexts where the non classical
reproducibility of quantum correlations is required.


title: Cryptanalysis of a new chaotic cryptosystem based on ergodicity

abstract:
  This paper analyzes the security of a recent cryptosystem based on the
ergodicity property of chaotic maps. It is shown how to obtain the secret key
using a chosen-ciphertext attack. Some other design weaknesses are also shown.


title:
Kerr and free-carrier ultrafast all-optical switching of GaAs/AlAs
  nanostructures near the three-photon edge of GaAs

abstract:
  We performed non-degenerate pump-probe experiments on a GaAs/AlAs photonic
structure. We switched the photonic properties using the optical Kerr effect
and free carriers excited by three photon absorption. From these measurements
we extracted the non-degenerate Kerr coefficients over a broad wavelength range
and we extracted the three photon absorption coefficient for GaAs at three
wavelengths in the near infrared. We show that the optical Kerr effect is large
enough to switch a cavity resonance with a high \emph{Q} ($Q>1000$) photonic
cavity.


title: Jets and environment of microquasars

abstract:
  Two relativistic X-ray jets have been detected with the Chandra X-ray
observatory from the black hole X-ray transient XTE J1550-564. We report a full
analysis of the evolution of the two jets with a gamma-ray burst external shock
model. A plausible scenario suggests a cavity outside the central source and
the jets first travelled with constant velocity and then are slowed down by the
interactions between the jets and the interstellar medium (ISM). The best
fitted radius of the cavity is $\sim$0.36 pc on the eastern side and $\sim$0.46
pc on the western side, and the densities also show asymmetry, of $\sim$0.015
cm$^{-3}$ on the east to $\sim$0.21 cm$^{-3}$ on the west. A large scale low
density region is also found in another microquasar system, H 1743-322. These
results are consistent with previous suggestions that the environment of
microquasars should be rather vacuous, compared to the normal Galactic
environment. A generic scenario for microquasar jets is proposed, classifying
the observed jets into three main categories, with different jet morphologies
(and sizes) corresponding to different scales of vacuous environments
surrounding them.


title: Enhancement of sudden death of entanglement for driven qubits

abstract:
  We study the recently discovered phenomena of sudden death of entanglement
for a system of two qubits, each of them independently longitudinally damped by
a reservoir and subjected to a continuous driving. We show that driving
produces, in the interaction picture, an effective bath that has elements
amounting to various extra sources of noise (transverse, thermal squeezed,
thermal longitudinal). As a result, the time of sudden death decreases due to
driving, which we verify as well by direct numerical calculation. We suggest
that this phenomenon can be studied systematically using superconducting qubits
driven by microwave fields.


title: On Transmission Line Resonances in High T$_C$ dc SQUIDs

abstract:
  In this paper, we study transmission line resonances in high $T_C$ dc SQUIDs.
These resonances are exhibited in the characteristics of SQUIDs which are
fabricated on substrates with high dielectric constant, such as strontium
titanate. The power balance equation is analytically derived both for symmetric
and asymmetric SQUIDs. Using this, we investigate SQUID current - voltage
$I(V)$, voltage - flux $V(\Phi)$ and voltage modulation $\Delta V$
characteristics.


title:
Existence of a critical point for the infinite divisibility of squares
  of Gaussian vectors in $R^{2}$ with non--zero mean

abstract:
  Let $G=(G_{1},G_{2})$ be a Gaussian vector in $R^{2}$ with $EG_{1}G_{2}\neq
0$. Let $c_{1},c_{2}\in R^{1}$. A necessary and sufficient condition for
$G=((G_{1}+c_{1}\alpha)^{2},(G_{2}+c_{2}\alpha)^{2})$ to be infinitely
divisible for all $\alpha\in R^{1}$ is that \[ \Ga_{i,i}\geq
\frac{c_{i}}{c_{j}}\Ga_{i,j}>0\qquad\forall 1\le i\ne j\le 2.\] In this paper
we show that when this does not hold there exists an $0<\alpha_{0}<\ff $ such
that $G=((G_{1}+c_{1}\alpha)^{2},(G_{2}+c_{2}\alpha)^{2})$ is infinitely
divisible for all $|\alpha|\leq \alpha_{0}$ but not for any $|\al|>\al_{0}$.


title:
Asymptotically self-similar propagation of the spherical ionization
  waves

abstract:
  It is shown that a new type of the self-similar spherical ionization waves
may exist in gases. All spatial scales and the propagation velocity of such
waves increase exponentially in time. Conditions for existence of these waves
are established, their structure is described and approximate analytical
relationships between the principal parameters are obtained. It is notable that
spherical ionization waves can serve as the simplest, but structurally complete
and physically transparent model of streamer in homogeneous electric field.


title:
On the origin of approximate custodial symmetry in the Two-Higgs Doublet
  Model

abstract:
  We argue that the consistent implementation of the multiple point principle
(MPP) in the general non-supersymmetric two Higgs doublet model (2HDM) can lead
to a set of approximate global custodial symmetries that ensure CP conservation
in the Higgs sector and the absence of flavour changing neutral currents (FCNC)
in the considered model. In particular the existence of a large set of
degenerate vacua at some high energy scale $\Lambda$ caused by the MPP can
result in approximate U(1) and Z(2) symmetries that suppress FCNC and
CP--violating interactions in the 2HDM. We explore the renormalisation group
(RG) flow of the Yukawa and Higgs couplings within the MPP inspired 2HDM with
approximate custodial symmetries and show that the solutions of the RG
equations are focused near quasi--fixed points at low energies if the MPP scale
scale $\Lambda$ is relatively high. We study the Higgs spectrum and couplings
near the quasi--fixed point at moderate values of $\tan\beta$ and compute a
theoretical upper bound on the lightest Higgs boson mass. If $\Lambda\gtrsim
10^{10} {GeV}$ the lightest CP--even Higgs boson is always lighter than $125
{GeV}$. When the MPP scale is low, the mass of the lightest Higgs particle can
reach $180-220 {GeV}$ while its coupling to the top quark can be significantly
larger than in the SM, resulting in the enhanced production of Higgs bosons at
the LHC.


title: Energy and Vorticity in Fast Rotating Bose-Einstein Condensates

abstract:
  We study a rapidly rotating Bose-Einstein condensate confined to a finite
trap in the framework of two-dimensional Gross-Pitaevskii theory in the strong
coupling (Thomas-Fermi) limit. Denoting the coupling parameter by $1/\eps^2$
and the rotational velocity by $\Omega$, we evaluate exactly the next to
leading order contribution to the ground state energy in the parameter regime
$|\log\eps|\ll \Omega\ll 1/(\eps^2|\log\eps|)$ with $\eps\to 0$. While the TF
energy includes only the contribution of the centrifugal forces the next order
corresponds to a lattice of vortices whose density is proportional to the
rotational velocity.


title: Semi-classical Analysis of Spin Systems near Critical Energies

abstract:
  The spectral properties of $su(2)$ Hamiltonians are studied for energies near
the critical classical energy $\epsilon_c$ for which the corresponding
classical dynamics presents hyperbolic points (HP). A general method leading to
an algebraic relation for eigenvalues in the vicinity of $\epsilon_c$ is
obtained in the thermodynamic limit, when the semi-classical parameter
$n^{-1}=(2s)^{-1}$ goes to zero (where $s$ is the total spin of the system).
Two applications of this method are given and compared with numerics. Matrix
elements of observables, computed between states with energy near $\epsilon_c$,
are also computed and shown to be in agreement with the numerical results.


title: Strongly Fillable Contact Manifolds and J-holomorphic Foliations

abstract:
  We prove that every strong symplectic filling of a planar contact manifold
admits a symplectic Lefschetz fibration over the disk, and every strong filling
of the 3-torus similarly admits a Lefschetz fibration over the annulus. It
follows that strongly fillable planar contact structures are also Stein
fillable, and all strong fillings of the 3-torus are equivalent up to
symplectic deformation and blowup. These constructions result from a
compactness theorem for punctured J-holomorphic curves that foliate a convex
symplectic manifold. We use it also to show that the compactly supported
symplectomorphism group on the cotangent bundle of the 2-torus is contractible,
and to define an obstruction to strong fillability that yields a
non-gauge-theoretic proof of Gay's recent nonfillability result for contact
manifolds with positive Giroux torsion.


title: Optical Properties of Superconducting Nanowire Single-Photon Detectors

abstract:
  We measured the optical absorptance of superconducting nanowire single photon
detectors. We found that 200-nm-pitch, 50%-fill-factor devices had an average
absorptance of 21% for normally-incident front-illumination of
1.55-um-wavelength light polarized parallel to the nanowires, and only 10% for
perpendicularly-polarized light. We also measured devices with lower
fill-factors and narrower wires that were five times more sensitive to
parallel-polarized photons than perpendicular-polarized photons. We developed a
numerical model that predicts the absorptance of our structures. We also used
our measurements, coupled with measurements of device detection efficiencies,
to determine the probability of photon detection after an absorption event. We
found that, remarkably, absorbed parallel-polarized photons were more likely to
result in detection events than perpendicular-polarized photons, and we present
a hypothesis that qualitatively explains this result. Finally, we also
determined the enhancement of device detection efficiency and absorptance due
to the inclusion of an integrated optical cavity over a range of wavelengths
(700-1700 nm) on a number of devices, and found good agreement with our
numerical model.


title:
Differential fast fixed-point algorithms for underdetermined
  instantaneous and convolutive partial blind source separation

abstract:
  This paper concerns underdetermined linear instantaneous and convolutive
blind source separation (BSS), i.e., the case when the number of observed mixed
signals is lower than the number of sources.We propose partial BSS methods,
which separate supposedly nonstationary sources of interest (while keeping
residual components for the other, supposedly stationary, "noise" sources).
These methods are based on the general differential BSS concept that we
introduced before. In the instantaneous case, the approach proposed in this
paper consists of a differential extension of the FastICA method (which does
not apply to underdetermined mixtures). In the convolutive case, we extend our
recent time-domain fast fixed-point C-FICA algorithm to underdetermined
mixtures. Both proposed approaches thus keep the attractive features of the
FastICA and C-FICA methods. Our approaches are based on differential sphering
processes, followed by the optimization of the differential nonnormalized
kurtosis that we introduce in this paper. Experimental tests show that these
differential algorithms are much more robust to noise sources than the standard
FastICA and C-FICA algorithms.


title: d=4 Attractors, Effective Horizon Radius and Fake Supergravity

abstract:
  We consider extremal black hole attractors (both BPS and non-BPS) for N=3 and
N=5 supergravity in d=4 space-time dimensions. Attractors for matter-coupled
N=3 theory are similar to attractors in N=2 supergravity minimally coupled to
Abelian vector multiplets. On the other hand, N=5 attractors are similar to
attractors in N=4 pure supergravity, and in such theories only 1\N-BPS
non-degenerate solutions exist. All the above mentioned theories have a simple
interpretation in the first order (fake supergravity) formalism. Furthermore,
such theories do not have a d=5 uplift. Finally we comment on the "duality"
relations among the attractor solutions of N\geq2 supergravities sharing the
same full bosonic sector.


title: Renewal series and square-root boundaries for Bessel processes

abstract:
  We show how a description of Brownian exponential functionals as a renewal
series gives access to the law of the hitting time of a square-root boundary by
a Bessel process. This extends classical results by Breiman and Shepp,
concerning Brownian motion, and recovers by different means, extensions for
Bessel processes, obtained independently by Delong and Yor.


title: Correct form of the electron wavefunction in periodic solids

abstract:
  The Bloch wavefunction leads either to mathematically impossible consequences
or suggests that the ground state energy is a function of size and shape when
the geometry of large crystals is considered in detail. It is incompatible with
the assumption underlying the Born-von Karman periodic boundary condition. The
source of the difficulty is the incorrect dependence of the Bloch wavefunction
on the wavenumber index k. The mathematically impossible consequences can be
overcome if the periodic part of the electron wavefunction is represented as
un(r), which is dependent only on the band index, n, and is independent of the
wavenumber index k. This correct form of the wavefunction is consistent with
the Bloch theorem and with all other properties of Bloch wavefunctions. The
correct form is also consistent with the Born-von Karman periodic boundary
condition. The correct form of the electronic wavefunction in a periodic solid
has profound consequences. It simplifies the calculation of electronic
structure as only one wavefunction per band, un(r), needs to be evaluated. It
brings about a conceptual unification between the band picture favored by
physicists and the bond picture favored by chemists. The correct form of the
electron wavefunction will simplify the understanding of many phenomena
involving valence electrons.


title: The HI - Star Formation Connection: Open Questions

abstract:
  We show data from the Survey of Ionization in Neutral Gas Galaxies (SINGG)
and Survey of Ultraviolet emission in Neutral Gas Galaxies (SUNGG) which survey
the star formation properties of HI selected galaxies as traced by H-alpha and
ultraviolet emission, respectively. The correlations found demonstrate a strong
relationship between the neutral ISM, young massive stars, and the evolved
stellar populations. For example the correlation between R band surface
brightness and the HI cycling time is tighter than the Kennicutt-Schmidt Star
Formation Law. Other scaling relations from SINGG give strong direct
confirmation of the downsizing scenario: low mass galaxies are more gaseous and
less evolved into stars than high mass galaxies. There are strong variations in
the H-alpha to UV flux ratios within and between galaxies. The only plausible
explanations for this result are that either the escape fraction of ionizing
photons or the upper end of the IMF varies with galaxy mass. We argue for the
latter interpretation, although either result has major implications for
astrophysics. A detailed dissection of the massive star content in the extended
HI disk of NGC2915 provides a consistent picture of continuing star formation
with a truncated or steep IMF, while other GALEX results indicate that star
formation edges seen in Halpha are not always apparent in the UV. These and
other recent results settle some old questions but open many new questions
about star formation and its relation to the ISM.


title: Duality for massive spin two theories in arbitrary dimensions

abstract:
  Using the parent Lagrangian approach we construct a dual formulation, in the
sense originally proposed by Curtright and Freund, of a massive spin two
Fierz-Pauli theory in arbitrary dimensions $D$. This is achieved in terms of a
mixed symmetry tensor $T_{A[B_{1}B_{2}... B_{D-2}]}$, without the need of
auxiliary fields. The relation of this method with an alternative formulation
based on a gauge symmetry principle proposed by Zinoviev is elucidated. We show
that the latter formulation in four dimensions, with a given gauge fixing
together with a definite sequence of auxiliary fields elimination via their
equations of motion, leads to the parent Lagrangian already considered by West
completed by a Fierz-Pauli mass term, which in turns yields the
Curtright-Freund action. This motivates our generalization to arbitrary
dimensions leading to the corresponding extension of the four dimensional
result. We identify the transverse true degrees of freedom of the dual theory
and verify that their number is in accordance with those of the massive
Fierz-Pauli field.


title: The Structure of Information Pathways in a Social Communication Network

abstract:
  Social networks are of interest to researchers in part because they are
thought to mediate the flow of information in communities and organizations.
Here we study the temporal dynamics of communication using on-line data,
including e-mail communication among the faculty and staff of a large
university over a two-year period. We formulate a temporal notion of "distance"
in the underlying social network by measuring the minimum time required for
information to spread from one node to another -- a concept that draws on the
notion of vector-clocks from the study of distributed computing systems. We
find that such temporal measures provide structural insights that are not
apparent from analyses of the pure social network topology. In particular, we
define the network backbone to be the subgraph consisting of edges on which
information has the potential to flow the quickest. We find that the backbone
is a sparse graph with a concentration of both highly embedded edges and
long-range bridges -- a finding that sheds new light on the relationship
between tie strength and connectivity in social networks.


title: Reentrant phase diagram and pH effects in cross-linked gelatin gels

abstract:
  Experimental results have shown that the kinetics of bond formation in
chemical crosslinking of gelatin solutions is strongly affected not only by
gelatin and reactant concentrations but also by the solution pH. We present an
extended numerical investigation of the phase diagram and of the kinetics of
bond formation as a function of the pH, via Monte Carlo simulations of a
lattice model for gelatin chains and reactant agent in solution. We find a
reentrant phase diagram, namely gelation can be hindered either by loop
formation, at low reactant concentrations, or by saturation of active sites of
the chains via formation of single bonds with crosslinkers, at high reactant
concentrations. The ratio of the characteristic times for the formation of the
first and of the second bond between the crosslinker and an active site of a
chain is found to depend on the reactant reactivity, in good agreement with
experimental data.


title:
Four-colour photometry of eclipsing binaries. XLI uvby light curves for
  AD Bootis, HW Canis Majoris, SW Canis Majoris, V636 Centauri, VZ Hydrae, and
  WZ Ophiuchi

abstract:
  CONTEXT: Accurate mass, radius, and abundance determinations from binaries
provide important information on stellar evolution, fundamental to central
fields in modern astrophysics and cosmology.
  AIMS: Within the long-term Copenhagen Binary Project, we aim to obtain
high-quality light curves and standard photometry for double-lined detached
eclipsing binaries with late A, F, and G type main-sequence components, needed
for the determination of accurate absolute dimensions and abundances, and for
detailed comparisons with results from recent stellar evolutionary models.
  METHODS: Between March 1985 and July 2007, we carried out photometric
observations of AD Boo, HW CMA, SW CMa, V636 Cen, VZ Hya, and WZ Oph at the
Str"omgren Automatic Telescope at ESO, La Silla.
  RESULTS: We obtained complete uvby light curves, ephemerides, and standard
uvby\beta indices for all six systems.For V636 Cen and HW CMa, we present the
first modern light curves, whereas for AD Boo, SW CMa, VZ Hya, and WZ Oph, they
are both more accurate and more complete than earlier data. Due to a high
orbital eccentricity (e = 0.50), combined with a low orbital inclination (i =
84.7), only one eclipse, close to periastron, occurs for HW CMa. For the two
other eccentric systems, V636 Cen (e = 0.134) and SW CMa (e = 0.316), apsidal
motion has been detected with periods of 5270 +/- 335 and 14900 +/- 3600 years,
respectively.


title:
CaII and NaI absorption signatures from extraplanar gas in the halo of
  the Milky Way

abstract:
  We analyse absorption characteristics and physical conditions of extraplanar
intermediate- and high-velocity gas to study the distribution of the neutral
and weakly ionised Milky Way halo gas and its relevance for the evolution of
the Milky Way and other spiral galaxies.
  We combine optical absorption line measurements of CaII/NaI and 21 cm
emission line observations of HI along 103 extragalactic lines of sight towards
quasars (QSOs) and active galactic nuclei (AGN). The archival optical spectra
were obtained with UVES at the ESO VLT, while the 21 cm HI observations were
carried out using the 100-m radio telescope at Effelsberg.
  The analysis of the UVES spectra shows that single and multi-component
CaII/NaI absorbers at intermediate and high velocities are present in about 35%
of the sight lines, indicating the presence of neutral extraplanar gas
structures. In some cases the CaII/NaI absorption is connected with HI
intermediate- or high-velocity gas, while other absorbers show no associated HI
emission.
  Our study suggests that the Milky Way halo is filled with a large number of
neutral gaseous structures whose high column density tail represents the
population of common HI high-velocity clouds seen in 21 cm surveys. The CaII
column density distribution follows a power-law which is comparable to the
distribution found for intervening metal-line systems toward QSOs. Many of the
statistical and physical properties of the CaII absorbers resemble those of
strong MgII absorbing systems observed in the circumgalactic environment of
other galaxies, suggesting that both absorber populations may be closely
related.


title:
Holomorphic Functions of Exponential Type and Duality for Stein Groups
  with Algebraic Connected Component of Identity

abstract:
  We suggest a generalization of Pontryagin duality from the category of
commutative Stein groups to the category of (not necessarily commutative) Stein
groups with algebraic connected component of identity. In contrast to the other
similar generalizations, in our approach the enveloping category consists of
Hopf algebras (in a proper symmetrical monoidal category).


title:
Effective Mass Ratio & positive colossal magnetoresistance of a
  Nano-wire

abstract:
  In the present work, a relation has been established between degree of
polarization and effective mass ratio (EMR) and magnetoresistance (MR) of
one-dimensional non-degenerate system (which can represent a nano-wire or a
linear chain of atoms and molecules in one dimension) by using a non-degenerate
Hubbard model, which includes diagonal and off-diagonal matrix elements of
Coulomb interaction. EMR is one of the most important property, which provides
information that how much itinerant the system is? Within the mean field
approximation, it is found that, due to the presence of off-diagonal elements,
the band narrowing effect dominates over the band splitting effect. The EMR
varies with degree of polarization. EMR for majority (up spin) carriers
decreases as magnetization increases below ferromagnetic transition
temperature. MR decreases as system is cooled below the ferromagnetic
transition temperature. A comparison of our results with existing experimental
observations is made.


title: Computing the Scalar Field Couplings in 6D Supergravity

abstract:
  Using non chiral supersymmetry in 6D space time, we compute the explicit
expression of the metric the scalar manifold $SO(1,1) \times \frac{SO(4,20)
}{SO(4) \times SO(20)}$ of the 10D type IIA superstring on generic K3. We
consider as well the scalar field self-couplings in the general case where the
non chiral 6D supergravity multiplet is coupled to generic n vector
supermultiplets with moduli space $SO(1,1) \times \frac{SO(4,n)}{SO(4) \times
SO(n)}$. We also work out a dictionary giving a correspondence between
hyperKahler geometry and the Kahler geometry of the Coulomb branch of 10D type
IIA on Calabi-Yau threefolds. Others features are also discussed.


title:
From B[e] to A[e]. On the peculiar variations of the SMC supergiant LHA
  115-S 23 (AzV 172)

abstract:
  Optical observations from 1989 of the SMC B[e] supergiant star S23 revealed
the presence of photospheric HeI absorption lines. In our high-resolution
optical spectra from 2000, however, we could not identify any HeI line. The
observed changes in spectral behaviour of S23 lead to different spectral
classifications at different observing epochs. The aim of this research is,
therefore, to find and discuss possible scenarios that might cause a
disappearance of the photospheric HeI absorption lines within a period of only
11 years. From our high-resolution optical spectra, we perform a detailed
investigation of the different spectral appearances of S23. We further
determine the projected rotational velocities of S23 in the two epochs of
observations. Based on its spectral appearance in 2000, we classify S23 as A1Ib
star with an effective temperature of about 9000 K. Further, an interstellar
extinction value of E(B-V) = 0.03 is derived. This is considerably lower than
the previously published value, which means that, if the circumstellar
extinction due to the stellar wind is neglected, the interstellar extinction,
and hence the luminosity of the star, are overestimated. We derive a rotation
velocity of v sin i = 150km/s, which means that S23 is rotating with about 75%
of its critical speed. The object S23 is thus the fourth B[e] supergiant with
confirmed high projected rotational velocity. The most striking result is the
apparent cooling of S23 by more than 1500 K with a simultaneous increase of its
rotation speed by about 35% within only 11 years. Since such a behaviour is
excluded by stellar evolution theories, we discuss possible scenarios for the
observed peculiar variations in S23.


title: A Computer Verified Theory of Compact Sets

abstract:
  Compact sets in constructive mathematics capture our intuition of what
computable subsets of the plane (or any other complete metric space) ought to
be. A good representation of compact sets provides an efficient means of
creating and displaying images with a computer. In this paper, I build upon
existing work about complete metric spaces to define compact sets as the
completion of the space of finite sets under the Hausdorff metric. This
definition allowed me to quickly develop a computer verified theory of compact
sets. I applied this theory to compute provably correct plots of uniformly
continuous functions.


title: Shephard-Todd-Chevalley Theorem for skew polynomial rings

abstract:
  We prove the following generalization of the classical
Shephard-Todd-Chevalley Theorem. Let $G$ be a finite group of graded algebra
automorphisms of a skew polynomial ring $A:=k_{p_{ij}}[x_1,...,x_n]$. Then the
fixed subring $A^G$ has finite global dimension if and only if $G$ is generated
by quasi-reflections. In this case the fixed subring $A^G$ is isomorphic a skew
polynomial ring with possibly different $p_{ij}$'s. A version of the theorem is
proved also for abelian groups acting on general quantum polynomial rings.


title: Hydrodynamic limit of gradient exclusion processes with conductances

abstract:
  Fix a strictly increasing right continuous with left limits function $W: \bb
R \to \bb R$ and a smooth function $\Phi : [l,r] \to \bb R$, defined on some
interval $[l,r]$ of $\bb R$, such that $0<b \le \Phi'\le b^{-1}$. We prove that
the evolution, on the diffusive scale, of the empirical density of exclusion
processes, with conductances given by $W$, is described by the weak solutions
of the non-linear differential equation $\partial_t \rho = (d/dx)(d/dW)
\Phi(\rho)$. We derive some properties of the operator $(d/dx)(d/dW)$ and prove
uniqueness of weak solutions of the previous non-linear differential equation.


title:
On a quantum model of a laser-interferometer measuring a weak classical
  force

abstract:
  We consider a solvable model of a laser-interferometer measuring a weak
classical force. The model takes into account dissipation of the energy by
transfer to the environment at zero temperature. The sensitivity (the
signal-to-noise ratio) of the device is defined as the corresponding ratio
between the mean value and the variance of a certain observable. We analyze the
dependence of the sensitivity upon the duration of the measurement and the
photon number. For parameters typical for the LIGO project, we discuss
numerical estimates.


title: Maximally Localized Wannier Functions within the FLAPW formalism

abstract:
  We report on the implementation of the Wannier Functions (WFs) formalism
within the full-potential linearized augmented plane wave method (FLAPW),
suitable for bulk, film and one-dimensional geometries. The details of the
implementation, as well as results for the metallic SrVO3, ferroelectric BaTiO3
grown on SrTiO3, covalently bonded graphene and a one-dimensional Pt-chain are
given. We discuss the effect of spin-orbit coupling on the Wannier Functions
for the cases of SrVO3 and platinum. The dependency of the WFs on the choice of
the localized trial orbitals as well as the difference between the maximally
localized and "first-guess" WFs are discussed. Our results on SrVO3 and BaTiO3,
e.g. the ferroelectric polarization of BaTiO3, are compared to results
published elsewhere and found to be in excellent agreement.


title: Anomalous Spin Response in Non-centrosymmetric Compounds

abstract:
  We examine static spin susceptibilities $\chi_{\alpha\beta}({\bf q})$ of spin
components $S_{\alpha}$ and $S_{\beta}$ in the non-centrosymmetric tetragonal
system. These show anomalous momentum dependences like $\chi_{xx}({\bf
q})-\chi_{yy}({\bf q})\sim q_x^2-q_y^2$ and $\chi_{xy}({\bf q})+\chi_{yx}({\bf
q})\sim q_x q_y$, which vanish in centrosymmetric systems. The magnitudes of
the anomalous spin susceptibilities are enhanced by the on-site Coulomb
interaction, especially, around an ordering wave vector. The significant and
anomalous momentum dependences of these susceptibilities are explained by a
group theoretical analysis. As the direct probe of the anomalous spin
susceptibility, we propose a polarized neutron scattering experiment.


title: MOHCS: Towards Mining Overlapping Highly Connected Subgraphs

abstract:
  Many networks in real-life typically contain parts in which some nodes are
more highly connected to each other than the other nodes of the network. The
collection of such nodes are usually called clusters, communities, cohesive
groups or modules. In graph terminology, it is called highly connected graph.
In this paper, we first prove some properties related to highly connected
graph. Based on these properties, we then redefine the highly connected
subgraph which results in an algorithm that determines whether a given graph is
highly connected in linear time. Then we present a computationally efficient
algorithm, called MOHCS, for mining overlapping highly connected subgraphs. We
have evaluated experimentally the performance of MOHCS using real and synthetic
data sets from computer-generated graph and yeast protein network. Our results
show that MOHCS is effective and reliable in finding overlapping highly
connected subgraphs. Keywords-component; Highly connected subgraph, clustering
algorithms, minimum cut, minimum degree


title: Negative dimensional approach to evaluating real integrals

abstract:
  In solving the differential equation for a non damped harmonic oscillator one
meets, after subjecting the equation to a Fourier transformation, an
integration in the complex $\omega$ plane. In most cases such an integral is
evaluated by calculating residues together with some physical input such as the
principle of causality to define which pole residues are relevant to the
physical problem. For this kind of application, Cauchy's theorem or residue
theorem can be applied to evaluate certain real integrals. Here we present an
alternative approach based on the concept of negative dimensional integration
to treat such integrals and give an specific example on how this is
accomplished.


title: Path Integrals for Potential Scattering

abstract:
  Two path integral representations for the $T$-matrix in nonrelativistic
potential scattering are derived and proved to produce the complete Born series
when expanded to all orders. They are obtained with the help of "phantom"
degrees of freedom which take away explicit phases that diverge for asymptotic
times. In addition, energy conservation is enforced by imposing a
Faddeev-Popov-like constraint in the velocity path integral. These expressions
may be useful for attempts to evaluate the path integral in real time and for
alternative multiple scattering expansions. Standard and novel eikonal-type
high-energy approximations and systematic expansions immediately follow.


title:
Absolute dimensions of eclipsing binaries. XXVI. Setting a new standard:
  Masses, radii, and abundances for the F-type systems AD Bootis, VZ Hydrae,
  and WZ Ophiuchi

abstract:
  We determine absolute dimensions and abundances for the three F-type
main-sequence detached eclipsing binaries AD Boo, VZ Hya, and WZ Oph and
perform a detailed comparison with results from recent stellar evolutionary
models. uvby light curves and standard photometry were obtained at ESO,radial
velocity observations at CfA facilities, and high-resolution spectra with ESO's
FEROS spectrograph. State-of-the-art methods were applied for the analyses.
Masses and radii that are precise to 0.5-0.7% and 0.4-0.9%, respectively, have
been established for the components, which span the ranges of 1.1 to 1.4 M_sun
and 1.1 to 1.6 R_sun. The [Fe/H] abundances are from -0.27 to +0.10, with
uncertainties between 0.07 and 0.15 dex. We find indications of a slight
alpha-element overabundance of [alpha/Fe] ~ +0.1$ for WZ Oph. The secondary
component of AD Boo and both components of WZ Oph appear to be slightly active.
Yale-Yonsai and Victoria-Regina evolutionary models fit the components of AD
Boo and VZ Hya almost equally well, assuming coeval formation, at ages of about
1.75/1.50 Gyr (AD Boo) and 1.25/1.00 Gyr (VZ Hya). BaSTI models, however,
predict somewhat different ages for the primary and secondary components. For
WZ Oph, the models from all three grids are significantly hotter than observed.
A low He content, decreased envelope convection coupled with surface activity,
and/or higher interstellar absorption would remove the discrepancy, but its
cause has not been definitively identified. We have demonstrated the power of
testing and comparing recent stellar evolutionary models using eclipsing
binaries, provided their abundances are known. The strongest limitations and
challenges are set by T_eff and interstellar absorption determinations, and by
their effects on and correlation with abundance results.


title: Dynamics of F/D networks: the role of bound states

abstract:
  We study, via numerical experiments, the role of bound states in the
evolution of cosmic superstring networks, being composed by p F-strings, q
D-strings and (p,q) bound states. We find robust evidence for scaling of all
three components of the network, independently of initial conditions. The
novelty of our numerical approach consists of having control over the initial
abundance of bound states. This indeed allows us to identify the effect of
bound states on the evolution of the network. Our studies also clearly show the
existence of an additional energy loss mechanism, resulting to a lower overall
string network energy, and thus scaling of the network. This new mechanism
consists of the formation of bound states with an increasing length.


title:
Ultra-High Energy Cosmic Rays Detected by the Pierre Auger Observatory:
  First Direct Evidence, and its Implications, that a Subset Originate in
  Nearby Radiogalaxies

abstract:
  (abridged) The Pierre Auger Collaboration has reported 27 Ultra-High Energy
Cosmic Ray Events (UHECRs) with energies above 56 EeV and well determined
arrival directions as of 2007 August 31. They find that the arrival directions
are not isotropic, but instead appear correlated with the positions of nearby
AGNs. Our aim was to determine the sources of these UHECRs by comparing their
arrival directions with more comprehensive source catalogs.
  Four (eight) of the 27 UHECRs with energy >56EeV detected by the Pierre Auger
Observatory have arrival directions within 1.5deg (3.5deg) of the extended
(>180kpc) radio structures of nearby radiogalaxies or the single nearby BLLac
with extended radio structure. Conversely the radio structures of three (six)
of all ten nearest extended radiogalaxies are within 1.5deg (3.5deg) of a
UHECR; three of the remaining four radiogalaxies are in directions with lower
exposure times. This correlation between nearby extended radiogalaxies and a
subset of UHECRs is significant at the 99.9% level. This is the first direct
observational proof that radio galaxies are a significant source of UHECRs. For
the remaining ~20 UHECRs, an isotropic distribution cannot be ruled out at high
significance. The correlation found by the Auger Collaboration between the 27
UHECRs and AGNs in the Veron-Cetty & Veron catalog at D < 71Mpc has a much
lower significance when one considers only the ~20 UHECRs not `matched' to
nearby extended radiogalaxies. No correlation is seen between UHECRs and
supernovae, supernova remnants, nearby galaxies, or nearby groups and clusters
of galaxies. The primary difference between the UHECR detections at the Pierre
Auger Observatory and previous experiments may thus be that the Southern
Hemisphere is more privileged with respect to nearby extended radiogalaxies.


title: Cylindrical Two-Dimensional Electron Gas in a Transverse Magnetic Field

abstract:
  We compute the single-particle states of a two-dimensional electron gas
confined to the surface of a cylinder immersed in a magnetic field. The
envelope-function equation has been solved exactly for both an homogeneous and
a periodically modulated magnetic field perpendicular to the cylinder axis. The
nature and energy dispersion of the quantum states reflects the interplay
between different lengthscales, namely, the cylinder diameter, the magnetic
length, and, possibly, the wavelength of the field modulation. We show that a
transverse homogeneous magnetic field drives carrier states from a quasi-2D
(cylindrical) regime to a quasi-1D regime where carriers form channels along
the cylinder surface. Furthermore, a magnetic field which is periodically
modulated along the cylinder axis may confine the carriers to tunnel-coupled
stripes, rings or dots on the cylinder surface, depending on the ratio between
the the field periodicity and the cylinder radius. Results in different regimes
are traced to either incipient Landau levels formation or Aharonov-Bohm
behaviour.


title: Sparse Regularization with $l^q$ Penalty Term

abstract:
  We consider the stable approximation of sparse solutions to non-linear
operator equations by means of Tikhonov regularization with a subquadratic
penalty term. Imposing certain assumptions, which for a linear operator are
equivalent to the standard range condition, we derive the usual convergence
rate $O(\sqrt{\delta})$ of the regularized solutions in dependence of the noise
level $\delta$. Particular emphasis lies on the case, where the true solution
is known to have a sparse representation in a given basis. In this case, if the
differential of the operator satisfies a certain injectivity condition, we can
show that the actual convergence rate improves up to $O(\delta)$.


title: Knot Group Epimorphisms, II

abstract:
  We consider the relations $\ge$ and $\ge_p$ on the collection of all knots,
where $k \ge k'$ (respectively, $k \ge_p k'$) if there exists an epimorphism
$\pi k \to \pi k'$ of knot groups (respectively, preserving peripheral
systems). When $k$ is a torus knot, the relations coincide and $k'$ must also
be a torus knot; we determine the knots $k'$ that can occur. If $k$ is a
2-bridge knot and $k \ge_p k'$, then $k'$ is a 2-bridge knot with determinant a
proper divisor of the determinant of $k$; only finitely many knots $k'$ are
possible.


title: The Precision Determination of Invisible-Particle Masses at the LHC

abstract:
  We develop techniques to determine the mass scale of invisible particles
pair-produced at hadron colliders. We employ the constrained mass variable
m_2C, which provides an event-by-event lower-bound to the mass scale given a
mass difference. We complement this variable with a new variable m_2C,UB which
provides an additional upper bound to the mass scale, and demonstrate its
utility with a realistic case study of a supersymmetry model. These variables
together effectively quantify the `kink' in the function Max m_T2 which has
been proposed as a mass-determination technique for collider-produced dark
matter. An important advantage of the m_2C method is that it does not rely
simply on the position at the endpoint, but it uses the additional information
contained in events which lie far from the endpoint. We found the mass by
comparing the HERWIG generated m_2C distribution to ideal distributions for
different masses. We find that for the case studied, with 100 fb^-1 of
integrated luminosity (about 400 signal events), the invisible particle's mass
can be measured to a precision of 4.1 GeV. We conclude that this technique's
precision and accuracy is as good as, if not better than, the best known
techniques for invisible-particle mass-determination at hadron colliders.