title: Comparison of Cluster Lensing Profiles with Lambda CDM Predictions

abstract:
  We derive lens distortion and magnification profiles of four well known
clusters observed with Subaru. Each cluster is very well fitted by the general
form predicted for Cold Dark Matter (CDM) dominated halos, with good
consistency found between the independent distortion and magnification
measurements. The inferred level of mass concentration is surprisingly high,
8<c_{vir}<15 (<c_{vir}> = 10.4 \pm 0.9), compared to the relatively shallow
profiles predicted by the Lambda CDM model, c_{vir}=5.1 \pm 1.1 (for <M_{vir}>
=1.25\times 10^{15}M_{\odot}/h). This represents a 4sigma discrepancy, and
includes the relatively modest effects of projection bias and profile evolution
derived from N-body simulations, which oppose each other with little residual
effect. In the context of CDM based cosmologies, this discrepancy implies
clusters collapse earlier (z\geq 1) than predicted (z<0.5), when the Universe
was correspondingly denser.


title:
Convergence of nonlocal threshold dynamics approximations to front
  propagation

abstract:
  In this note we prove that appropriately scaled threshold dynamics-type
algorithms corresponding to the fractional Laplacian of order $\alpha \in
(0,2)$ converge to moving fronts. When $\alpha \geqq 1$ the resulting interface
moves by weighted mean curvature, while for $\alpha <1$ the normal velocity is
nonlocal of ``fractional-type.'' The results easily extend to general nonlocal
anisotropic threshold dynamics schemes.


title: Refraction and absorption of x rays by laser-dressed atoms

abstract:
  X-ray refraction and absorption by neon atoms under the influence of an 800
nm laser with an intensity of 10^13 W/cm^2 is investigated. For this purpose,
we use an ab initio theory suitable for optical strong-field problems. Its
results are interpreted in terms of a three-level model. On the Ne 1s --> 3p
resonance, we find electromagnetically induced transparency (EIT) for x rays.
Our work opens novel perspectives for ultrafast x-ray pulse shaping.


title: Algorithms for B\"uchi Games

abstract:
  The classical algorithm for solving B\"uchi games requires time $O(n\cdot m)$
for game graphs with $n$ states and $m$ edges. For game graphs with constant
outdegree, the best known algorithm has running time $O(n^2/\log n)$. We
present two new algorithms for B\"uchi games. First, we give an algorithm that
performs at most $O(m)$ more work than the classical algorithm, but runs in
time O(n) on infinitely many graphs of constant outdegree on which the
classical algorithm requires time $O(n^2)$. Second, we give an algorithm with
running time $O(n\cdot m\cdot\log\delta(n)/\log n)$, where $1\le\delta(n)\le n$
is the outdegree of the game graph. Note that this algorithm performs
asymptotically better than the classical algorithm if $\delta(n)=O(\log n)$.


title: Topological Sigma B Model in 4-Dimensions

abstract:
  We propose a 4-dimensional version of topological sigma B-model, governing
maps from a smooth compact 4-manifold M to a Calabi-Yau target manifold X. The
theory depends on on complex structure of X, while is independent of Kaehler
metric of X. The theory is also a 4-dimensiona topological field theory in the
sense that the theory is independent of variation of Riemannian metric of the
source 4-manifold M, potentially leading to new smooth invariant of
4-manifolds. We argue that the theory also comes with a topological family
parametrized by the extended moduli space of complex structures.


title: Stochastic Limit-Average Games are in EXPTIME

abstract:
  The value of a finite-state two-player zero-sum stochastic game with
limit-average payoff can be approximated to within $\epsilon$ in time
exponential in a polynomial in the size of the game times polynomial in
logarithmic in $\frac{1}{\epsilon}$, for all $\epsilon>0$.


title: Triplet Extended Supersymmetric Standard Model

abstract:
  We revisit an extension of the MSSM by adding a hypercharge-neutral,
SU(2)-triplet chiral superfield. Similar to the NMSSM, the triplet gives an
additional contribution to the quartic coupling in the Higgs potential, and the
mass of the lightest CP-even Higgs boson can be greater than tne mass of the
Z-bosn at tree-level. In addition to discussing the perturbativity,
fine-tuning, and decoupling issues of this model, we compute the dominant
1-loop corrections to the mass of the lightest CP-even Higgs boson from the
triplet sector. When the Higgs-Higgs-Triplet coupling in the superpotential is
comparable to the top Yukawa coupling, we find that the Higgs mass can be as
heavy as 140 GeV even without the traditional contributions from the top--s-top
sector, and at the same time consistent with the precision electroweak
constraints. At the expense of having Landau poles before the GUT scale, this
opens up a previously forbidden region in the MSSM parameter space where both
s-tops are light. In addition to having relatively small fine-tuning (about one
part in 30), this leads to a gluo-philic Higgs boson whose production via
gluon-gluon fusion at the LHC can be twice as large as the SM prediction.


title: So you want to be a professional astronomer!

abstract:
  Exotic workplace locales, amazing discoveries, and fame (but probably not
fortune) await those who persevere on the path leading to a career as a
professional astronomer. So how do you join the elite ranks of professional
astronomy? Here are some suggestions for how to get a job in astronomy.


title: (GL(2n,C),SP(2n,C)) is a Gelfand Pair

abstract:
  We prove that (GL_{2n}(C),Sp_{2n}(C)) is a Gelfand pair. More precisely, we
show that for an irreducible smooth admissible Frechet representation (\pi,E)
of GL_{2n}(C) the space of continuous functionals Hom_{Sp_{2n}(\cc)}(E,C) is at
most one dimensional. For this we show that any distribution on GL_{2n}(C)
invariant with respect to the double action Sp_{2n}(C) \times Sp_{2n}(C) is
transposition invariant. Such a result was previously proven for p-adic fields
by M. Heumos and S. Rallis.


title: Period Doubling in Small Multiply Connected Superconductors

abstract:
  It is shown that for superconductors with circumference $2\pi R$ approaching
BCS coherence length $\xi_0$ minimal period of the response of all
thermodynamic quantities to external magnetic field is set by $hc/e$ i.e. twice
the corresponding value for the bulk case. This is explained by the dependence
of internal energy of Cooper pairs on their center of mass motion which leads,
in particular, to a transition offset between different current-carrying
states. Explicit calculation of the transition offset is done for the case of
s-wave superconducting cylinder with $R \gg \xi_0$ and turns out to be
exponentially small. A possible enhancement of the effect for nodal
superconductors is suggested. Similar conclusions should also apply to the
response of charged or neutral superfluids to rotation.


title:
Fast Monte Carlo Estimation of Timing Yield: Importance Sampling with
  Stochastic Logical Effort (ISLE)

abstract:
  In the nano era in integrated circuit fabrication technologies, the
performance variability due to statistical process and circuit parameter
variations is becoming more and more significant. Considerable effort has been
expended in the EDA community during the past several years in trying to cope
with the so-called statistical timing problem. Most of this effort has been
aimed at generalizing the static timing analyzers to the statistical case. In
this paper, we take a pragmatic approach in pursuit of making the Monte Carlo
method for timing yield estimation practically feasible. The Monte Carlo method
is widely used as a golden reference in assessing the accuracy of other timing
yield estimation techniques. However, it is generally believed that it can not
be used in practice for estimating timing yield as it requires too many costly
full circuit simulations for acceptable accuracy. In this paper, we present a
novel approach to constructing an improvedMonte Carlo estimator for timing
yield which provides the same accuracy as the standard Monte Carlo estimator,
but at a cost of much fewer full circuit simulations. This improved estimator
is based on a novel combination of a variance reduction technique, importance
sampling, and a stochastic generalization of the logical effort formalism for
cheap but approximate delay estimation. The results we present demonstrate that
our improved yield estimator achieves the same accuracy as the standard Monte
Carlo estimator at a cost reduction reaching several orders of magnitude.


title: Sloppiness, robustness, and evolvability in systems biology

abstract:
  The functioning of many biochemical networks is often robust -- remarkably
stable under changes in external conditions and internal reaction parameters.
Much recent work on robustness and evolvability has focused on the structure of
neutral spaces, in which system behavior remains invariant to mutations.
Recently we have shown that the collective behavior of multiparameter models is
most often 'sloppy': insensitive to changes except along a few 'stiff'
combinations of parameters, with an enormous sloppy neutral subspace.
Robustness is often assumed to be an emergent evolved property, but the
sloppiness natural to biochemical networks offers an alternative non-adaptive
explanation. Conversely, ideas developed to study evolvability in robust
systems can be usefully extended to characterize sloppy systems.


title:
On Full Diversity Space-Time Block Codes with Partial Interference
  Cancellation Group Decoding

abstract:
  In this paper, we propose a partial interference cancellation (PIC) group
decoding for linear dispersive space-time block codes (STBC) and a design
criterion for the codes to achieve full diversity when the PIC group decoding
is used at the receiver. A PIC group decoding decodes the symbols embedded in
an STBC by dividing them into several groups and decoding each group separately
after a linear PIC operation is implemented. It can be viewed as an
intermediate decoding between the maximum likelihood (ML) receiver that decodes
all the embedded symbols together, i.e., all the embedded symbols are in a
single group, and the zero-forcing (ZF) receiver that decodes all the embedded
symbols separately and independently, i.e., each group has and only has one
embedded symbol, after the ZF operation is implemented. Our proposed design
criterion for the PIC group decoding to achieve full diversity is an
intermediate condition between the loosest ML full rank criterion of codewords
and the strongest ZF linear independence condition of the column vectors in the
equivalent channel matrix. We also propose asymptotically optimal (AO) group
decoding algorithm, which is an intermediate decoding between the MMSE decoding
algorithm and the ML decoding algorithm. The design criterion for the PIC group
decoding applies to the AO group decoding algorithm. It is well-known that the
symbol rate for a full rank linear STBC can be full, i.e., n_t for n_t transmit
antennas. It has been recently shown that its rate is upper bounded by 1 if a
code achieves full diversity with a linear receiver. The intermediate criterion
proposed in this paper provides the possibility for codes of rates between n_t
and 1 that achieve full diversity with a PIC group decoding. This therefore
provides a complexity-performance-rate tradeoff.


title: Sequential Design of Experiments via Linear Programming

abstract:
  The celebrated multi-armed bandit problem in decision theory models the basic
trade-off between exploration, or learning about the state of a system, and
exploitation, or utilizing the system. In this paper we study the variant of
the multi-armed bandit problem where the exploration phase involves costly
experiments and occurs before the exploitation phase; and where each play of an
arm during the exploration phase updates a prior belief about the arm. The
problem of finding an inexpensive exploration strategy to optimize a certain
exploitation objective is NP-Hard even when a single play reveals all
information about an arm, and all exploration steps cost the same.
  We provide the first polynomial time constant-factor approximation algorithm
for this class of problems. We show that this framework also generalizes
several problems of interest studied in the context of data acquisition in
sensor networks. Our analyses also extends to switching and setup costs, and to
concave utility objectives.
  Our solution approach is via a novel linear program rounding technique based
on stochastic packing. In addition to yielding exploration policies whose
performance is within a small constant factor of the adaptive optimal policy, a
nice feature of this approach is that the resulting policies explore the arms
sequentially without revisiting any arm. Sequentiality is a well-studied
concept in decision theory, and is very desirable in domains where multiple
explorations can be conducted in parallel, for instance, in the sensor network
context.


title: Motional Spin Relaxation in Large Electric Fields

abstract:
  We discuss the precession of spin-polarized Ultra Cold Neutrons (UCN) and
$^{3}$He atoms in uniform and static magnetic and electric fields and calculate
the spin relaxation effects from motional $v\times E$ magnetic fields. Particle
motion in an electric field creates a motional $v\times E$ magnetic field,
which when combined with collisions, produces variations of the total magnetic
field and results in spin relaxation of neutron and $^{3}$He samples. The spin
relaxation times $T_{1}$ (longitudinal) and $T_{2}$ (transverse) of
spin-polarized UCN and $^{3}$He atoms are important considerations in a new
search for the neutron Electric Dipole Moment at the SNS \emph{nEDM}
experiment. We use a Monte Carlo approach to simulate the relaxation of spins
due to the motional $v\times E$ field for UCN and for $^{3}$He atoms at
temperatures below $600,\mathrm{mK}$. We find the relaxation times for the
neutron due to the $v\times E$ effect to be long compared to the neutron
lifetime, while the $^{3}$He relaxation times may be important for the
\emph{nEDM} experiment.


title:
Perturbation Theory Reloaded II: Non-linear Bias, Baryon Acoustic
  Oscillations and Millennium Simulation In Real Space

abstract:
  We calculate the non-linear galaxy power spectrum in real space, including
non-linear distortion of the Baryon Acoustic Oscillations, using the standard
3rd-order perturbation theory (PT). The calculation is based upon the
assumption that the number density of galaxies is a local function of the
underlying, non-linear density field. The galaxy bias is allowed to be both
non-linear and stochastic. We show that the PT calculation agrees with the
galaxy power spectrum estimated from the Millennium Simulation, in the weakly
non-linear regime (defined by the matter power spectrum) at high redshifts,
$1\le z\le6$. We also show that, once 3 free parameters characterizing galaxy
bias are marginalized over, the PT power spectrum fit to the Millennium
Simulation data yields unbiased estimates of the distance scale, $D$, to within
the statistical error. This distance scale corresponds to the angular diameter
distance, $D_A(z)$, and the expansion rate, $H(z)$, in real galaxy surveys. Our
results presented in this paper are still restricted to real space. The future
work should include the effects of non-linear redshift space distortion.
Nevertheless, our results indicate that non-linear galaxy bias in the weakly
non-linear regime at high redshifts is reasonably under control.


title: Electronic Duality in Strongly Correlated Matter

abstract:
  Superconductivity develops from an attractive interaction between itinerant
electrons that creates electron pairs which condense into a macroscopic quantum
state--the superconducting state. On the other hand, magnetic order in a metal
arises from electrons localized close to the ionic core and whose interaction
is mediated by itinerant electrons. The dichotomy between local moment magnetic
order and superconductivity raises the question of whether these two states can
coexist and involve the same electrons. Here we show that the single
4f-electron of cerium in CeRhIn5 simultaneously produces magnetism,
characteristic of localization, and superconductivity that requires itinerancy.
The dual nature of the 4f-electron allows microscopic coexistence of
antiferromagnetic order and superconductivity whose competition is tuned by
small changes in pressure and magnetic field. Electronic duality contrasts with
conventional interpretations of coexisting spin-density magnetism and
superconductivity and offers a new avenue for understanding complex states in
classes of materials.


title: The reflection of very cold neutrons from diamond powder nanoparticles

abstract:
  We study possibility of efficient reflection of very cold neutrons (VCN) from
powders of nanoparticles. In particular, we measured the scattering of VCN at a
powder of diamond nanoparticles as a function of powder sample thickness,
neutron velocity and scattering angle. We observed extremely intense scattering
of VCN even off thin powder samples. This agrees qualitatively with the model
of independent nanoparticles at rest. We show that this intense scattering
would allow us to use nanoparticle powders very efficiently as the very first
reflectors for neutrons with energies within a complete VCN range up to
$10^{-4}$ eV.


title:
On the moduli space of negatively curved metrics of a hyperbolic
  manifold

abstract:
  We study the moduli space of negatively curved metrics of a hyperbolic
manifold.


title: Observations of 1999 YC and the Breakup of the Geminid Stream Parent

abstract:
  Apollo asteroid 1999 YC may share a dynamical association with the
Phaethon-Geminid stream complex (Ohtsuka et al. 2008). Here, we present
photometric observations taken to determine the physical properties of 1999 YC.
The object shows a nearly neutral reflection spectrum, similar to but slightly
redder than related objects 3200 Phaethon and 2005 UD. Assuming an albedo equal
to 3200 Phaethon's we find that the diameter is 1.4+/-0.1 km. Time-resolved
broad-band photometry yields a double-peaked rotational period of
4.4950+/-0.0010 hr while the range of the lightcurve indicates an elongated
shape having a projected axis ratio near 1.9:1. Surface brightness models
provide no evidence of lasting mass loss of the kind seen in active short
period cometary nuclei. An upper limit to the mass loss is set at about 0.001
kg/s, corresponding to an upper limit on the fraction of the surface that could
be sublimating water ice of 0.001. If sustained over the 1000 yr age of the
Geminid stream, the total mass loss from 1999 YC (3e7 kg) would be small
compared to the reported stream mass (1e12 - 1e13 kg), suggesting that the
stream is the product of catastrophic, rather than steady-state, breakup of the
parent object.


title:
Compensation of wake-field-driven energy spread in Energy Recovery
  Linacs

abstract:
  Energy Recovery Linacs provide high-energy beams, but decelerate those beams
before dumping them, so that their energy is available for the acceleration of
new particles. During this deceleration, any relative energy spread that is
created at high energy is amplified by the ratio between high energy and dump
energy. Therefore, Energy Recovery Linacs are sensitive to energy spread
acquired at high energy, e.g. from wake fields. One can compensate the
time-correlated energy spread due to wakes via energy-dependent time-of-flight
terms in appropriate sections of an Energy Recovery Linac, and via
high-frequency cavities. We show that nonlinear time-of-flight terms can only
eliminate odd orders in the correlation between time and energy, if these terms
are created by a beam transport within the linac that is common for
accelerating and decelerating beams. If these two beams are separated, so that
different beam transport sections can be used to produce time-of-flight terms
suitable for each, also even-order terms in the energy spread can be
eliminated. As an example, we investigate the potential of using this method
for the Cornell x-ray Energy Recovery Linac. Via quadratic time-of-flight
terms, the energy spread can be reduced by 66%. Alternatively, since the energy
spread from the dominantly resistive wake fields of the analysed accelerator is
approximately harmonic in time, a high-frequency cavity could diminish the
energy spread by 81%. This approach would require bunch-lengthening and
recompression in separate sections for accelerating and decelerating beams.
Such sections have therefore been included in Cornell's x-ray Energy Recovery
Linac design.


title:
Dipole and quadrupole solitons in optically-induced two-dimensional
  defocusing photonic lattices

abstract:
  Dipole and quadrupole solitons in a two-dimensional optically induced
defocus- ing photonic lattice are theoretically predicted and experimentally
observed. It is shown that in-phase nearest-neighbor dipole and out-of-phase
next-nearest-neighbor dipoles exist and can be stable in the intermediate
intensity regime. The other types of dipoles are always unstable. In-phase
nearest-neighbor quadrupoles are also numerically obtained, and may also be
linearly stable. Out-of-phase, nearest-neighbor quadrupoles are found to be
typically unstable. These numerical results are found to be aligned with the
main predictions obtained analytically in the discrete nonlinear Schroedinger
model. Finally, experimental results are presented for both dipole and
quadrupole structures, indicating that self-trapping of such structures in the
defocusing lattice can be realized for the length of the nonlinear crystal (10
mm).


title: On the $k$-free divisor problem

abstract:
  Let $\Delta^{(k)}(x)$ denote the error term of the $k$-free divisor problem
for $k\geq 2$. In this paper we establish an asymptotic formula of the integral
$\int_1^T|\Delta^{(k)}(x)|^2dx$ for each $k\geq 4.$


title:
Orthogonal Trigonometric Polynomials: Riemann-Hilbert Analysis and
  Relations with OPUC

abstract:
  In this paper, we study the theory of orthogonal trigonometric polynomials
(OTP). We obtain asymptotics of OTP with positive and analytic weight functions
by Riemann-Hilbert approach and find they have relations with orthogonal
polynomials on the unit circle (OPUC). By the relations and the theory of OPUC,
we also get four-terms recurrent formulae, Christoffel-Darboux formula and some
properties of zeros for orthogonal trigonometric polynomials.


title: On the Capacity of the Diamond Half-Duplex Relay Channel

abstract:
  We consider a diamond-shaped dual-hop communication system consisting a
source, two parallel half-duplex relays and a destination. In a single antenna
configuration, it has been previously shown that a two-phase node-scheduling
algorithm, along with the decode and forward strategy can achieve the capacity
of the diamond channel for a certain symmetric channel gains [1]. In this
paper, we obtain a more general condition for the optimality of the scheme in
terms of power resources and channel gains. In particular, it is proved that if
the product of the capacity of the simultaneously active links are equal in
both transmission phases, the scheme achieves the capacity of the channel.


title: Microlensing Detections of Moons of Exoplanets

abstract:
  We investigate the characteristic of microlensing signals of Earth-like moons
orbiting ice-giant planets. From this, we find that non-negligible satellite
signals occur when the planet-moon separation is similar to or greater than the
Einstein radius of the planet. We find that the satellite signal does not
diminish with the increase of the planet-moon separation beyond the Einstein
radius of the planet unlike the planetary signal which vanishes when the planet
is located well beyond the Einstein radius of the star. We also find that the
satellite signal tends to have the same sign as that of the planetary signal.
These tendencies are caused by the lensing effect of the star on the moon in
addition to the effect of the planet. We determine the range of satellite
separations where the microlensing technique is optimized for the detections of
moons. By setting an upper limit as the angle-average of the projected Hill
radius and a lower limit as the half of the Einstein radius of the planet, we
find that the microlensing method would be sensitive to moons with projected
separations from the planet of $0.05 {\rm AU} \lesssim d_{\rm p} \lesssim 0.24
{\rm AU}$ for a Jupiter-mass planet, $0.03 {\rm AU}\lesssim d_{\rm p} \lesssim
0.17 {\rm AU}$ for a Saturn-mass planet, and $0.01 {\rm AU} \lesssim d_{\rm p}
\lesssim 0.08 {\rm AU}$ for a Uranus-mass planet. We compare the
characteristics of the moons to be detected by the microlensing and transit
techniques


title: The Legend of Cosmological Homogeneity

abstract:
  For more than a half century cosmologists have been guided by the assumption
that matter is distributed homogeneously on sufficiently large scales. On the
other hand, observations have consistently yielded evidence for inhomogeneity
in the distribution of matter right up to the limits of most surveys. The
apparent paradox can be understood in terms of the role that paradigms play in
the evolution of science.


title: Geometrical Construction of Supertwistor Theory

abstract:
  Supertwistor theory is geometrically constructed based on the SUSY Hopf map.
We derive a new incidence relation for the geometrical supertwistor theory. The
present supertwistor exhibits remarkable properties: Minkowski space need not
be complexified to introduce spin degrees of freedom, and even number SUSY is
{automatically} incorporated by the geometrical set-up. We also develop a
theory for massless free particle in Minkowski superspace, which physically
corresponds to the geometrical supertwistor theory. The spin degrees of freedom
are originated from fermionic momenta as well as fermionic coordinates. The
geometrical supertwistor is quantized to reproduce same physical contents as in
the original supertwistor theory. Relationships to superspin formalism and SUSY
quantum Hall effect are also discussed.


title:
The Space-Cone Gauge, Lorentz Invariance and On-Shell Recursion for
  One-Loop Yang-Mills amplitudes

abstract:
  Recursion relations are succinctly obtained for $(++... +)$ and $(-++... +)$
amplitudes in the context of the space-cone gauge in QCD. We rely on the
helicity symmetry of the problems to dictate our choices of reference twistors
and the momentum shifts to complexify the amplitudes. Of great importance is
the power of gauge Lorentz invariance, which is enough to determine the soft
factors in the latter cases.


title:
Small Approximate Pareto Sets for Bi-objective Shortest Paths and Other
  Problems

abstract:
  We investigate the problem of computing a minimum set of solutions that
approximates within a specified accuracy $\epsilon$ the Pareto curve of a
multiobjective optimization problem. We show that for a broad class of
bi-objective problems (containing many important widely studied problems such
as shortest paths, spanning tree, and many others), we can compute in
polynomial time an $\epsilon$-Pareto set that contains at most twice as many
solutions as the minimum such set. Furthermore we show that the factor of 2 is
tight for these problems, i.e., it is NP-hard to do better. We present upper
and lower bounds for three or more objectives, as well as for the dual problem
of computing a specified number $k$ of solutions which provide a good
approximation to the Pareto curve.


title:
Unusual Pseudogap-like Features Observed in Iron Oxypnictide
  Superconductors

abstract:
  We have performed a temperature-dependent angle-integrated laser
photoemission study of iron oxypnictide superconductors LaFeAsO:F and LaFePO:F
exhibiting critical transition temperatures (Tc's) of 26 K and 5 K,
respectively. We find that high-Tc LaFeAsO:F exhibits a temperature-dependent
pseudogap-like feature extending over ~0.1 eV about the Fermi level at 250 K,
whereas such a feature is absent in low-Tc LaFePO:F. We also find ~20-meV
pseudogap-like features and signatures of superconducting gaps both in
LaFeAsO:F and LaFePO:F. We discuss the possible origins of the unusual
pseudogap-like features through comparison with the high-Tc cuprates.


title:
Quantum Hamiltonian diagonalization and Equations of Motion with Berry
  Phase Corrections

abstract:
  It has been recently found that the equations of motion of several
semiclassical systems must take into account anomalous velocity terms arising
from Berry phase contributions. Those terms are for instance responsible for
the spin Hall effect in semiconductors or the gravitational birefringence of
photons propagating in a static gravitational field. Intensive ongoing research
on this subject seems to indicate that actually a broad class of quantum
systems might have their dynamics affected by Berry phase terms. In this
article we review the implication of a new diagonalization method for generic
matrix valued Hamiltonians based on a formal expansion in power of $\hbar$. In
this approach both the diagonal energy operator and dynamical operators which
depend on Berry phase terms and thus form a noncommutative algebra, can be
expanded in power series in \hbar $. Focusing on the semiclassical
approximation, we will see that a large class of quantum systems, ranging from
relativistic Dirac particles in strong external fields to Bloch electrons in
solids have their dynamics radically modified by Berry terms.


title:
Theoretical evidences for enhanced superconducting transition
  temperature of CaSi$_2$ in a high-pressure AlB$_2$ phase

abstract:
  By means of first-principles calculations, we studied stable lattice
structures and estimated superconducting transition temperature of CaSi$_2$ at
high pressure. Our simulation showed stability of the AlB$_2$ structure in a
pressure range above 17 GPa. In this structure, doubly degenerated optical
phonon modes, in which the neighboring silicon atoms oscillate alternately in a
silicon plane, show prominently strong interaction with the conduction
electrons. In addition there exists a softened optical mode (out-of-plan motion
of silicon atoms), whose strength of the electron-phonon interaction is nearly
the same as the above mode. The density of states at the Fermi level in the
AlB$_2$ structure is higher than that in the trigonal structure. These findings
and the estimation of the transition temperature strongly suggest that higher
$T_{\rm c}$ is expected in the AlB$_2$ structure than the trigonal structures
which are known so far.


title:
Associated production of prompt photons and heavy quarks in off-shell
  gluon-gluon fusion

abstract:
  In the framework of the kt-factorization approach, we study the production of
prompt photons associated with heavy (charm and beauty) quarks in hadron-hadron
collisions at high energies. Our consideration is based on the amplitude for
the production of a single photon associated with a quark pair in the fusion of
two off-shell gluons. The total and differential cross sections are presented
and the conservative error analysis is performed. Two sets of unintegrated
gluon distributions in the proton have been used in numerical calculation: the
one obtained from Ciafaloni-Catani-Fiorani-Marchesini evolution equation and
the other from Kimber-Martin-Ryskin prescription. The theoretical results are
compared with recent experimental data taken by the CDF collaboration at the
Fermilab Tevatron. Our analysis extends to specific angular correlations
between the produced prompt photons and muons originating from semileptonic
decays of the final charmed or beauty quarks. We point out the importance of
such observables, which can serve as a crucial test for the unintegrated gluon
densities in a proton. Finally, we extrapolate the theoretical predictions to
the CERN LHC energies. This paper is dedicated to the memory of P.F. Ermolov,
who died on May 14, 2008.


title: Generalized W-states and Quantum Communication Protocols

abstract:
  We consider W-states and generalized W-states for $n$-qubit systems. We
obtain conditions to use these states as quantum resources to teleport unknown
states. Only a limited class of multi-qubit states can be teleported. For
$one$-qubit states, we use protocols which are simple extensions of the
conventional teleportation protocol. We also show that these resource states
can be used to transmit {\em at most} $n + 1$ classical bits by sending $n$
qubits if the appropriate conditions are met. Therefore these states are not
suitable for maximal teleportation or superdense coding when $ n > 3$.


title: Phase Transitions for the Groeth Rate of Linear Stochastic Evolutions

abstract:
  We consider a simple discrete-time Markov chain with values in
$[0,\infty)^{Z^d}$. The Markov chain describes various interesting examples
such as oriented percolation, directed polymers in random environment, time
discretizations of binary contact path process and the voter model. We study
the phase transition for the growth rate of the "total number of particles" in
this framework. The main results are roughly as follows: If $d \ge 3$ and the
Markov chain is "not too random", then, with positive probability, the growth
rate of the total number of particles is of the same order as its expectation.
If on the other hand, $d=1,2$, or the Markov chain is "random enough", then the
growth rate is slower than its expectation. We also discuss the above phase
transition for the dual processes and its connection to the structure of
invariant measures for the Markov chain with proper normalization.


title: Subtleties in the quasi-classical calculation of Hawking radiation

abstract:
  he quasi-classical method of deriving Hawking radiation is investigated. In
order to recover the original Hawking temperature one must take into account a
previously ignored contribution coming from the temporal part of the action.
This contribution plus a contribution coming from the spatial part of the
action gives the correct temperature.


title: Regularity issues in the problem of fluid structure interaction

abstract:
  We investigate the evolution of rigid bodies in a viscous incompressible
fluid. The flow is governed by the 2D Navier-Stokes equations, set in a bounded
domain with Dirichlet boundary conditions. The boundaries of the solids and the
domain have H\"older regularity $C^{1, \alpha}$, $0 < \alpha \le 1$. First, we
show the existence and uniqueness of strong solutions up to collision. A key
ingredient is a BMO bound on the velocity gradient, which substitutes to the
standard $H^2$ estimate for smoother domains. Then, we study the asymptotic
behaviour of one $C^{1, \alpha}$ body falling over a flat surface. We show that
collision is possible in finite time if and only if $\alpha < 1/2$.


title:
The Araucaria Project. The Distance to the Local Group Galaxy WLM from
  Near-Infrared Photometry of Cepheid Variables

abstract:
  We have obtained deep images in the near-infrared J and K filters for several
fields in the Local Group galaxy WLM. We report intensity mean magnitudes for
31 Cepheids located in these fields which we previously discovered in a
wide-field optical imaging survey of WLM. The data define tight
period-luminosity relations in both near-infrared bands which we use to derive
the total reddening of the Cepheids in WLM and the true distance modulus of the
galaxy from a multiwavelength analysis of the reddened distance moduli in the
VIJK bands. From this, we obtain the values E(B-V) = 0.082 $\pm$ 0.02, and
$(m-M)_{0} = 24.924 \pm 0.042$ mag, with a systematic uncertainty in the
distance of about $\pm$ 3%. This Cepheid distance agrees extremely well with
the distance of WLM determined from the I-band TRGB method by ourselves and
others. Most of the reddening of the Cepheids in WLM (0.06 mag) is produced
inside the galaxy, demonstrating again the need for an accurate determination
of the total reddening and/or the use of infrared photometry to derive Cepheid
distances which are accurate to 3% or better, even for small irregular galaxies
like WLM.


title: Universal Upper Bound for the Growth of Artin Monoids

abstract:
  In this paper we study the growth rates of Artin monoids and we show that 4
is a universal upper bound. We also show that the generating functions of the
associated right-angled Artin monoids are given by families of Chebyshev
polynomials. Applications to Artin groups and positive braids are given.


title:
The stellar-wind envelope around the supernova XRF/GRB060218/SN2006aj
  massive progenitor star

abstract:
  In BTA spectra of the supernova SN2006aj, identified with the X-ray flash
(XRF) and gamma-ray burst XRF/GRB060218/SN2006aj, we detected details
interpreted as hydrogen lines, which is a sign of stellar-wind envelope around
a massive progenitor star of the gamma-ray burst. Results of modeling two early
spectra obtained with the BTA in 2.55 and 3.55 days after the explosion of Type
Ic supernova SN2006aj (z=0.0331) are presented. The spectra were modeled in the
Sobolev approximation with the SYNOW code (Branch et al. 2001; Elmhamdi et al.
2006). In the spectra of the optical afterglow of the X-ray flash XRF/GRB060218
we detected spectral features interpreted as (1) the H_alpha PCyg profile for
the velocity 33000 km s$^{-1}$ -- a wide and almost unnoticeable deformation of
continuum in the range of $\simeq5600 - 6600\AA$ for the first epoch (2.55
days) and (2) a part (``remnant'') of the H_alpha PCyg profile in absorption
blueshifted by 24000 km s$^{-1}$ -- a wide spectral feature with a minimum at
$\simeq6100\AA$ (the rest wavelength) for the second epoch (3.55 days). Taking
into consideration early BTA observations and spectra obtained with other
telescopes (ESO Lick, ESO VLT, NOT) before 2006 Feb. 23 UT, it can be said that
we observe evolution of optical spectra of Type Ic core-collapse supernova SN
2006aj during {\it transition} from the short phase related to the shock
breakout to outer layers of the stellar-wind envelope to spectra of the phase
of increasing brightness corresponding to radioactive heating. Signs of
hydrogen in spectra of the gamma-ray burst afterglow were detected for the
first time.


title: Collinear ordering of easy-axis triangular lattice antiferromagnets

abstract:
  Antiferromagnetically coupled moments on the frustrated triangular lattice
typically order in a coplanar state at low temperature. Here, we demonstrate
that the presence of not-very-large easy axis single ion anisotropy leads to an
interesting orientationally ordered collinear state in triangular lattice
antiferromagnets with moments $S \ge 3/2$. This ordered state breaks the
symmetry of $\pi/3$ rotations about a lattice site, while leaving intact the
translational symmetry of the lattice.


title: A tunable solid-on-solid model of surface growth

abstract:
  We have performed a detailed Monte Carlo study of a diffusionless
$(1+1)$-dimensional solid-on-solid model of particle deposition and evaporation
that not only tunes the roughness of an equilibrium surface but also
demonstrates the need for more than two exponents to characterize it. The
tunable parameter, denoted by $\mu$, in this model is the dimensionless surface
tension per unit length. For $\mu < 0$, the surface becomes increasingly
spikier and its average width grows linearly with time; for $\mu = 0$, its
width grows as $\sqrt{t}$. On the other hand, for positive $\mu$, the surface
width shows the standard scaling behavior, $\la \sigma_m(t)\ra \sim
M^{\alpha}f(t/M^{\alpha /\beta})$ where $M$ is the substrate size and $f(x) \to
const (x^{\beta})$ for $x$ large (small). The roughness exponent, $\alpha =
1/2$ for $\mu \leq 2$, and $ = 3/5, 4/5 & \sim 1$ for $\mu = 5, 6 & 7$
respectively; the growth exponent, $\beta = 1/4$ for $\mu \leq 2$ and $= 1/2$
for $\mu > \sim 3.5$ respectively. These exponents are different from those of
the height-difference correlation function,$\alpha ' = 1/2, \beta ' = 1/4$ and
$z' = 2$, for higher values of $\mu$ suggesting thereby that the surface could
be self-constraining.


title:
Disjointness of representations arising in harmonic analysis on the
  infinite-dimensional unitary group

abstract:
  We prove pairwise disjointness of representations T_{z,w} of the
infinite-dimensional unitary group. These representations provide a natural
generalization of the regular representation for the case of "big" group
U(\infty). They were introduced and studied by G.Olshanski and A.Borodin.
  Disjointness of the representations can be reduced to disjointness of certain
probability measures on the space of paths in the Gelfand-Tsetlin graph. We
prove the latter disjointness using probabilistic and combinatorial methods.


title: Super Schrodinger algebra in AdS/CFT

abstract:
  We discuss (extended) super Schrodinger algebras obtained as subalgebras of
the superconformal algebra psu(2,2|4). The Schrodinger algebra with two spatial
dimensions can be embedded into so(4,2). In the superconformal case the
embedded algebra may be enhanced to the so-called super Schrodinger algebra. In
fact, we find an extended super Schrodinger subalgebra of psu(2,2|4). It
contains 24 supercharges (i.e., 3/4 of the original supersymmetries) and the
generators of so(6), as well as the generators of the original Schrodinger
algebra. In particular, the 24 supercharges come from 16 rigid supersymmetries
and half of 16 superconformal ones. Moreover, this superalgebra contains a
smaller super Schrodinger subalgebra, which is a supersymmetric extension of
the original Schrodinger algebra and so(6) by eight supercharges (half of 16
rigid supersymmetries). It is still a subalgebra even if there are no so(6)
generators. We also discuss super Schrodinger subalgebras of the superconformal
algebras, osp(8|4) and osp(8^*|4).


title: On the solutions of Knizhnik-Zamolodchikov system

abstract:
  We consider the Knizhnik-Zamolodchikov system of linear differential
equations. The coefficients of this system are rational functions. We prove
that under some conditions the solution of KZ system is rational too. We give
the method of constructing the corresponding rational solution. We deduce the
asymptotic formulas for the solution of KZ system when $\rho$ is integer.


title: Le probleme de Bogomolov effectif sur les varietes abeliennes

abstract:
  We give a new lower bound for the essential minimum of subvarieties of
abelian varieties with small codimension, under a conjecture about ordinary
primes in abelian varieties. This lower bound is already known in the toric
case since the work of Amoroso and David. It is the best expected, "up to an
epsilon", in the degree of the subvariety.


title: Search for WMAP-Compatible Simple SO(10) SUSY GUTs

abstract:
  Unification of GUT-scale t-b-\tau Yukawa couplings is a significant feature
of simple SO(10) SUSY GUTs. Here we present the results of a search that used
the Markov Chain Monte Carlo technique to investigate regions of Yukawa
unification and WMAP-compatible dark matter relic density in SO(10)-like MSSM
parameter spaces. We mention the possible LHC signatures of Yukawa unified
scenarios and discuss the consequences for dark matter.


title: Dynamical Emergence of FRW Cosmological Models

abstract:
  Recent astronomical observations strongly indicate that the current Universe
is undergoing an accelerated phase of expansion. The discovery of this fact was
unexpected and resulted in the comeback of cosmological constant. The
conception of standard cosmological model has its roots in this context. The
paper relates to the methodological status of effective theories in the context
of cosmological investigations. We argue that the standard cosmological model
(LCDM model) as well as the CDM have a status of effective theories only,
similarly to the standard model of particle physics. The LCDM model is studied
from the point of view of the methodological debate on reductionism and
epistemological emergence in the science. It is shown in the paper that
bifurcation as well as structural instability notion can be useful in the
detection of emergence the LCDM model from the CDM model. We demonstrate that
the structural stability of the LCDM model can explain the flexibility of the
model to accommodation of the observational data. We show that LCDM model can
be derived from CDM as the bifurcation. It is an example of acausal derivation
of Lambda term. The case study of emergence of LCDM model suggests that it can
be understood in terms of bifurcation and structural stability issue. The
reduction from the upper models represented in terms of dynamical system to
low-level ones can be realized in any case by application of a mathematical
limit (boundary crossing) with respect to the model parameter. It is a simple
consequence of mathematical theorem about smooth dependence solutions with
respect to time, initial condition and the parameters.


title: Subwavelength internal imaging by means of the wire medium

abstract:
  Evanescent wave amplification is observed, for the first time to our
knowledge, inside a half-wavelength-thick wire medium slab used for
subwavelength imaging. The wire medium is analyzed using both a spatially
dispersive finite-difference time-domain (FDTD) method and a full-wave
commercial electromagnetic simulator CST Microwave Studio. In this work we
demonstrate that subwavelength details of a source placed at a distance of
one-tenth of a wavelength from a wire medium slab can be detected inside the
slab with a resolution of approximately one-tenth of a wavelength in spite of
the fact that they cannot be resolved at the front interface of the device, due
to the rapid decay of evanescent spatial harmonics in free space.


title:
Low-energy radiative-capture reactions within two-cluster
  coupled-channel description

abstract:
  The formalism that describes radiative-capture reactions at low energies
within an extended two-cluster potential model is presented. Construction of
the operator of single-photon emission is based on a generalisation of the
Siegert theorem with which the amplitude of the electromagnetic process is
constructed in an explicitly gauge-independent way. While the starting point
for this construction is a microscopic (single-nucleon) current model, the
resulting operator of low-energy photon emission by a two-cluster system is
expressed in terms of macroscopic quantities for the clusters and does not
depend directly on their intrinsic coordinates and momenta. The multichannel
algebraic scattering (MCAS) approach has been used to construct the initial-
and final-state wave functions. We present a general expression for the
scattering wave function obtained from the MCAS T matrix taking into account
inelastic channels and Coulomb distortion. The developed formalism has been
tested on the 3He(alpha,gamma)7Be reaction cross section at astrophysical
energies. The energy dependence of the evaluated cross section and S factor
agrees well with that extracted from measurement though the calculated
quantities slightly overestimate data.


title: Halos of Modified Gravity

abstract:
  We describe how a certain simple modification of general relativity, in which
the local cosmological constant is allowed to depend on the space-time
curvature, predicts the existence of halos of modified gravity surrounding
spherically-symmetric objects. We show that the gravitational mass of an object
weighed together with its halo can be much larger than its gravitational mass
as seen from inside the halo. This effect could provide an alternative
explanation of the dark-matter phenomenon in galaxies. In this case, the local
cosmological constant in the solar system must be some six orders of magnitude
larger than its cosmic value obtained in the supernovae type Ia experiments.
This is well within the current experimental bounds, but may be directly
observable in the future high-precision experiments.


title:
Star formation in the hosts of high-z QSOs: Evidence from Spitzer PAH
  detections

abstract:
  We present Spitzer rest-frame mid-infrared spectroscopy of twelve z~2
mm-bright type 1 QSOs, selected from unlensed and lensed QSO samples and
covering a range of AGN optical luminosities L_5100=10^45 to 10^47 erg/s. On
top of the AGN continuum, we detect PAH emission from luminous star formation
in nine objects individually as well as in the composite spectrum for the full
sample. PAH luminosity and rest frame far-infrared luminosity correlate and
extend the similar correlation for lower luminosity local QSOs. This provides
strong evidence for intense star formation in the hosts of these mm-bright
QSOs, sometimes exceeding 1000 Msun/yr and dominating their rest frame
far-infrared emission. The PAH-based limit on star formation rates is lower for
luminous z~2 QSOs that are not preselected for their mm emission. Partly
dependent on systematic changes of the AGN dust covering factor and the dust
spectral energy distribution of the AGN proper, the spectral energy
distributions of mm-faint high-z QSOs may be AGN dominated out to rest frame
far-infrared wavelengths. Towards the most luminous high-z QSOs, there is a
flattening of the relation between star formation and AGN luminosity that is
observed for lower redshift QSOs. No QSO in our sample has a PAH-measured star
formation rate in excess of 3000 Msun/yr.


title: The effect of structure formation on the expansion of the universe

abstract:
  Observations of the expansion rate of the universe at late times disagree by
a factor of 1.5-2 with the prediction of homogeneous and isotropic models based
on ordinary matter and gravity. We discuss how the departure from linearly
perturbed homogeneity and isotropy due to structure formation could explain
this discrepancy. We evaluate the expansion rate in a dust universe which
contains non-linear structures with a statistically homogeneous and isotropic
distribution. The expansion rate is found to increase relative to the exactly
homogeneous and isotropic case by a factor of 1.1-1.3 at some tens of billion
of years. The timescale follows from the cold dark matter transfer function and
the amplitude of primordial perturbations without additional free parameters.


title: Finger Indexed Sets: New Approaches

abstract:
  In the particular case we have insertions/deletions at the tail of a given
set S of $n$ one-dimensional elements, we present a simpler and more concrete
algorithm than that presented in [Anderson, 2007] achieving the same (but also
amortized) upper bound of $O(\sqrt{logd/loglogd})$ for finger searching
queries, where $d$ is the number of sorted keys between the finger element and
the target element we are looking for. Furthermore, in general case we have
insertions/deletions anywhere we present a new randomized algorithm achieving
the same expected time bounds. Even the new solutions achieve the optimal
bounds in amortized or expected case, the advantage of simplicity is of great
importance due to practical merits we gain.


title:
Deeply Virtual Compton Scattering at HERA and Prospects on Nucleon
  Tomography

abstract:
  Standard parton distribution functions contain neither information on the
correlations between partons nor on their transverse motion, then a vital
knowledge about the three dimensional structure of the nucleon is lost. Hard
exclusive processes, in particular DVCS, are essential reactions to go beyond
this standard picture. In the following, we examine the most recent data and
their implication on the quarks/gluons imaging (tomography) of the nucleon.


title: Generalizations of Gronwall-Bihari Inequalities on Time Scales

abstract:
  We establish some nonlinear integral inequalities for functions defined on a
time scale. The results extend some previous Gronwall and Bihari type
inequalities on time scales. Some examples of time scales for which our results
can be applied are provided. An application to the qualitative analysis of a
nonlinear dynamic equation is discussed.


title: Implicit higher derivatives, and a formula of Comtet and Fiolet

abstract:
  Let F(x,y) be a function of two variables, and suppose y = f(x) satisfies
F(x,y)=0 in some range. Then dy/dx = -Fx/Fy, where Fx and Fy denote the partial
derivatives of F with respect to x and y. It is natural to seek a general
expression for the higher derivatives d^ny/dx^n, in terms of partial
derivatives of F, and such an expression was given in 1974 by L. Comtet and M.
Fiolet. Their formula, however, contains some errors. In this note, we give a
corrected expression. We give a derivation using Lagrange inversion and also an
elementary proof by induction. We further correct a minor error in Comtet and
Fiolet's expression for the number of terms in their formula.


title:
MAPEL: Achieving Global Optimality for a Non-convex Wireless Power
  Control Problem

abstract:
  Achieving weighted throughput maximization (WTM) through power control has
been a long standing open problem in interference-limited wireless networks.
The complicated coupling between the mutual interferences of links gives rise
to a non-convex optimization problem. Previous work has considered the WTM
problem in the high signal to interference-and-noise ratio (SINR) regime, where
the problem can be approximated and transformed into a convex optimization
problem through proper change of variables. In the general SINR regime,
however, the approximation and transformation approach does not work. This
paper proposes an algorithm, MAPEL, which globally converges to a global
optimal solution of the WTM problem in the general SINR regime. The MAPEL
algorithm is designed based on three key observations of the WTM problem: (1)
the objective function is monotonically increasing in SINR, (2) the objective
function can be transformed into a product of exponentiated linear fraction
functions, and (3) the feasible set of the equivalent transformed problem is
always normal although not necessarily convex. The MAPLE algorithm finds the
desired optimal power control solution by constructing a series of polyblocks
that approximate the feasible SINR region in increasing precision. Furthermore,
by tuning the approximation factor in MAPEL, we could engineer a desirable
tradeoff between optimality and convergence time. MAPEL provides an important
benchmark for performance evaluation of other heuristic algorithms targeting
the same problem. With the help of MAPEL, we evaluate the performance of
several respective algorithms through extensive simulations.


title: Analytical formulation for soliton-potential dynamics

abstract:
  An analytical model for the soliton-potential interaction is presented, by
constructing a collective coordinate for the system. Most of the characters of
the interaction are derived analytically while they are calculated by other
models numerically. We will find that the behaviour of the soliton is like a
point particle living under the influence of a complicated potential which is a
function of soliton velocity and the potential parameters. The analytic model
does not have a clear prediction for the islands of initial velocities in which
the soliton may reflect back or escape over the potential well.


title:
Sivers Effect for Pion and Kaon Production in Semi-Inclusive Deep
  Inelastic Scattering

abstract:
  We study the Sivers effect in the transverse single spin asymmetries (SSA)
for pion and kaon production in semi-inclusive deep inelastic scattering
(SIDIS) processes. We perform a fit of A^sin(phi_h-phi_S)_UT which, by
including recent high statistics experimental data for pion and kaon production
from HERMES and COMPASS Collaborations, allows a new determination of the
Sivers distribution functions for quarks and antiquarks with u, d and s
flavours. Estimates for forthcoming SIDIS experiments at COMPASS and JLab are
given.


title: Critical properties of a dilute O($n$) model on the kagome lattice

abstract:
  A critical dilute O($n$) model on the kagome lattice is investigated
analytically and numerically. We employ a number of exact equivalences which,
in a few steps, link the critical O($n$) spin model on the kagome lattice to
the exactly solvable critical $q$-state Potts model on the honeycomb lattice
with $q=(n+1)^2$. The intermediate steps involve the random-cluster model on
the honeycomb lattice, and a fully packed loop model with loop weight
$n'=\sqrt{q}$ and a dilute loop model with loop weight $n$, both on the kagome
lattice. This mapping enables the determination of a branch of critical points
of the dilute O($n$) model, as well as some of its critical properties. For
$n=0$, this model reproduces the known universal properties of the $\theta$
point describing the collapse of a polymer. For $n\neq 0$ it displays a line of
multicritical points, with the same universal properties as a branch of
critical behavior that was found earlier in a dilute O($n$) model on the square
lattice. These findings are supported by a finite-size-scaling analysis in
combination with transfer-matrix calculations.


title:
Time-preserving structural stability of hyperbolic differential dynamics
  with noncompact phase spaces

abstract:
  In this paper, we study the structural stability of hyperbolic differential
systems on Euclidean spaces using Liao theory.


title: A Quasi Curtis-Tits-Phan theorem for the symplectic group

abstract:
  We obtain the symplectic group $\SP(V)$ as the universal completion of an
amalgam of low rank subgroups akin to Levi components. We let $\SP(V)$ act
flag-transitively on the geometry of maximal rank subspaces of $V$. We show
that this geometry and its rank $\ge 3$ residues are simply connected with few
exceptions. The main exceptional residue is described in some detail. The
amalgamation result is then obtained by applying Tits' lemma. This provides a
new way of recognizing the symplectic groups from a small collection of small
subgroups.


title: Canonical polygon Queries on the plane: a New Approach

abstract:
  The polygon retrieval problem on points is the problem of preprocessing a set
of $n$ points on the plane, so that given a polygon query, the subset of points
lying inside it can be reported efficiently.
  It is of great interest in areas such as Computer Graphics, CAD applications,
Spatial Databases and GIS developing tasks. In this paper we study the problem
of canonical $k$-vertex polygon queries on the plane. A canonical $k$-vertex
polygon query always meets the following specific property: a point retrieval
query can be transformed into a linear number (with respect to the number of
vertices) of point retrievals for orthogonal objects such as rectangles and
triangles (throughout this work we call a triangle orthogonal iff two of its
edges are axis-parallel).
  We present two new algorithms for this problem. The first one requires
$O(n\log^2{n})$ space and $O(k\frac{log^3n}{loglogn}+A)$ query time. A simple
modification scheme on first algorithm lead us to a second solution, which
consumes $O(n^2)$ space and $O(k \frac{logn}{loglogn}+A)$ query time, where $A$
denotes the size of the answer and $k$ is the number of vertices.
  The best previous solution for the general polygon retrieval problem uses
$O(n^2)$ space and answers a query in $O(k\log{n}+A)$ time, where $k$ is the
number of vertices. It is also very complicated and difficult to be implemented
in a standard imperative programming language such as C or C++.


title: Analytic multiplicative cocycles over holomorphic dynamical systems

abstract:
  We prove some properties of analytic multiplicative and sub-multiplicative
cocycles. The results allow to construct natural invariant analytic sets
associated to complex dynamical systems.


title: Resolving disagreement for eta/s in a CFT plasma at finite coupling

abstract:
  The ratio of shear viscosity to entropy density in a strongly coupled CFT
plasma can be computed using the AdS/CFT correspondence either from equilibrium
correlation functions or from the Janik-Peschanski dual of the boost invariant
plasma expansion. We point out that the previously found disagreement for eta/s
at finite t' Hooft coupling is resolved once the incoming-wave boundary
condition for metric fluctuations at the horizon of the dual geometry is
properly imposed.


title: Assessing Random Dynamical Network Architectures for Nanoelectronics

abstract:
  Independent of the technology, it is generally expected that future nanoscale
devices will be built from vast numbers of densely arranged devices that
exhibit high failure rates. Other than that, there is little consensus on what
type of technology and computing architecture holds most promises to go far
beyond today's top-down engineered silicon devices. Cellular automata (CA) have
been proposed in the past as a possible class of architectures to the von
Neumann computing architecture, which is not generally well suited for future
parallel and fine-grained nanoscale electronics. While the top-down engineered
semi-conducting technology favors regular and locally interconnected
structures, future bottom-up self-assembled devices tend to have irregular
structures because of the current lack precise control over these processes. In
this paper, we will assess random dynamical networks, namely Random Boolean
Networks (RBNs) and Random Threshold Networks (RTNs), as alternative computing
architectures and models for future information processing devices. We will
illustrate that--from a theoretical perspective--they offer superior properties
over classical CA-based architectures, such as inherent robustness as the
system scales up, more efficient information processing capabilities, and
manufacturing benefits for bottom-up designed devices, which motivates this
investigation. We will present recent results on the dynamic behavior and
robustness of such random dynamical networks while also including manufacturing
issues in the assessment.


title: The flaring and quiescent components of the solar corona

abstract:
  The solar corona is a template to understand stellar activity. The Sun is a
moderately active star, and its corona differs from active stars: active
stellar coronae have a double-peaked EM(T) with the hot peak at 8-20 MK, while
the non flaring solar corona has one peak at 1-2 MK. We study the average
contribution of flares to the solar EM(T) to investigate indirectly the
hypothesis that the hot peak of the EM(T) of active stellar coronae is due to a
large number of unresolved solar-like flares, and to infer properties on the
flare distribution from nano- to macro-flares. We measure the disk-integrated
time-averaged emission measure, EM_F(T), of an unbiased sample of solar flares
analyzing uninterrupted GOES/XRS light curves over time intervals of one month.
We obtain the EM_Q(T) of quiescent corona for the same time intervals from the
Yohkoh/SXT data. To investigate how EM_F(T) and EM_Q(T) vary with the solar
cycle, we evaluate them at different phases of the cycle (from Dec. 1991 to
Apr. 1998). Irrespective of the solar cycle phase, EM_F(T) appears like a peak
of the distribution significantly larger than the values of EM_Q(T) for T~5-10
MK. As a result the time-averaged EM(T) of the whole solar corona is
double-peaked, with the hot peak, due to time-averaged flares, located at
temperature similar of that of active stars, but less enhanced. The EM_F(T)
shape supports the hypothesis that the hot EM(T) peak of active coronae is due
to unresolved solar-like flares. If this is the case, quiescent and flare
components should follow different scaling laws for increasing stellar
activity. In the assumption that the heating of the corona is entirely due to
flares, from nano- to macro-flares, then either the flare distribution or the
confined plasma response to flares, or both, are bimodal.


title: Whittaker Modules for the Virasoro Algebra

abstract:
  Whittaker modules have been well studied in the setting of complex semisimple
Lie algebras. Their definition can easily be generalized to certain other Lie
algebras with triangular decomposition, including the Virasoro algebra. We
define Whittaker modules for the Virasoro algebra and obtain analogues to
several results from the classical setting, including a classification of
simple Whittaker modules by central characters and composition series for
general Whittaker modules.


title: Pions in the quark matter phase diagram

abstract:
  The relationship between mesonic correlations and quantum condensates in the
quark matter phase diagram is explored within a quantum field theoretical
approach of the Nambu and Jona-Lasinio (NJL) type. Mean-field values in the
scalar meson and diquark channels are order parameters signalling the
occurrence of quark condensates, entailing chiral symmetry breaking (chi SB)
and color superconductivity (2SC) in quark matter. We investigate the spectral
properties of scalar and pseudoscalar meson excitations in the phase diagram in
Gaussian approximation and show that outside the chi SB region where the pion
is a zero-width bound state, there are two regions where it can be considered
as a quasi-bound state with a lifetime exceeding that of a typical heavy-ion
collision fireball: (A) the high-temperature chi SB crossover region at low
densities and (B) the high-density color superconducting phase at temperatures
below 100 MeV.


title: Gravitation equations and space-time relativity

abstract:
  In contrast to electrodynamics, Einstein's gravitation equations are not
invariant with respect to a wide class of the mapping of field variables which
leave equations of motion of test particles in a given coordinate system
invariant. It seems obvious enough that just these mappings should play a role
of gauge transformations of the variables in differential equations of
gravitational field. We consider here in short a gauge-invariant bimetric
generalisation of the Einstein equations which does not contradict availabel
observation data. Physical interpretation of the bimetricity based on
relativity of space-time with respect to used reference frame, following
conceptually from old Poincar\'{e} fundamental ideas, is proposed..


title:
Bayesian approach to clustering real value, categorical and network
  data: solution via variational methods

abstract:
  Data clustering, including problems such as finding network communities, can
be put into a systematic framework by means of a Bayesian approach. The
application of Bayesian approaches to real problems can be, however, quite
challenging. In most cases the solution is explored via Monte Carlo sampling or
variational methods. Here we work further on the application of variational
methods to clustering problems. We introduce generative models based on a
hidden group structure and prior distributions. We extend previous attends by
Jaynes, and derive the prior distributions based on symmetry arguments. As a
case study we address the problems of two-sides clustering real value data and
clustering data represented by a hypergraph or bipartite graph. From the
variational calculations, and depending on the starting statistical model for
the data, we derive a variational Bayes algorithm, a generalized version of the
expectation maximization algorithm with a built in penalization for model
complexity or bias. We demonstrate the good performance of the variational
Bayes algorithm using test examples.


title:
Increasing Linear Dynamic Range of Commercial Digital Photocamera Used
  in Imaging Systems with Optical Coding

abstract:
  Methods of increasing linear optical dynamic range of commercial photocamera
for optical-digital imaging systems are described. Use of such methods allows
to use commercial photocameras for optical measurements. Experimental results
are reported.


title:
Equivalent characterizations of partial randomness for a recursively
  enumerable real

abstract:
  A real number \alpha is called recursively enumerable if there exists a
computable, increasing sequence of rational numbers which converges to \alpha.
The randomness of a recursively enumerable real \alpha can be characterized in
various ways using each of the notions; program-size complexity, Martin-L\"{o}f
test, Chaitin's \Omega number, the domination and \Omega-likeness of \alpha,
the universality of a computable, increasing sequence of rational numbers which
converges to \alpha, and universal probability. In this paper, we generalize
these characterizations of randomness over the notion of partial randomness by
parameterizing each of the notions above by a real number T\in(0,1]. We thus
present several equivalent characterizations of partial randomness for a
recursively enumerable real number.


title:
Use of Combined Hartree-Fock-Roothaan Theory in Evaluation of Lowest
  States of K [Ar]4s^0 3d^1 and Cr+ [Ar]4s^0 3d^5 Isoelectronic Series Over
  Noninteger n-Slater Type Orbitals

abstract:
  By the use of integer and noninteger n-Slater Type Orbitals in combined
Hartree-Fock-Roothaan method, self consistent field calculations of orbital and
lowest states energies have been performed for the isoelectronic series of open
shell systems K [Ar]4s^0 3d^1 2(D) (Z=19-30) and Cr+ [Ar] 4s^0 3d^5 6(S)
(Z=24-30). The results of calculations for the orbital and total energies
obtained from the use of minimal basis sets of integer- and noninteger n-Slater
Type Orbitals are given in tables. The results are compared with the
extended-basis Hartree-Fock computations. The orbital and total energies are in
good agreement with those presented in the literature. The results are
accurately and considerably can be useful in the application of
non-relativistic and relativistic combined Hartree-Fock-Roothaan approach for
heavy atomic systems.


title: Finite Rank Toeplitz Operators: Some Extensions of D.Luecking's Theorem

abstract:
  The recent theorem by D.Luecking about finite rank Bergman-Toeplitz operators
is extended to weights being distributions with compact support and to the
spaces of harmonic functions.


title: Singular Solutions of Hessian Fully Nonlinear Elliptic Equations

abstract:
  We study Hessian fully nonlinear uniformly elliptic equations and show that
the second derivatives of viscosity solutions of those equations (in 12 or more
dimensions) can blow up in an interior point of the domain. We prove that the
optimal interior regularity of such solutions is no more than C^{1+\epsilon},
showing the optimality of the known interior regularity result. The same is
proven for Isaacs equations. We prove the existence of non-smooth solutions to
fully nonlinear Hessian uniformly elliptic equations in 11 dimensions. We study
also the possible singularity of solutions of Hessian equations defined in a
neighborhood of a point and prove that a homogeneous order 0<\alpha<1 solution
of a Hessian uniformly elliptic equation in a punctured ball should be radial.


title:
Contractive piecewise continuous maps modeling networks of inhibitory
  neurons

abstract:
  We prove that a topologically generic network (an open and dense set of
networks) of three or more inhibitory neurons have periodic behavior with a
finite number of limit cycles that persist under small perturbations of the
structure of the network. The network is modeled by the Poincare transformation
which is piecewise continuous and locally contractive on a compact region B of
a finite dimensional manifold, with the separation property: it transforms
homeomorphically the different continuity pieces of B into pairwise disjoint
sets.


title: An improved estimate on sums of product sets

abstract:
  In a recent paper \cite{Gl} A. Glibichuk proved that if $A,B$ are subsets of
an arbitrary finite filed $\F_q$, such that $|A||B|>q$, then $16AB = \F_q$. We
improve this to $10AB = \F_q.$


title: Resolving distance ambiguities towards 6.7 GHz methanol masers

abstract:
  Distances to most star forming regions are determined using kinematics,
through the assumption that the observed radial velocity arises from the motion
of the source with respect to the Sun resulting from the differential rotation
of Galaxy. The primary challenge associated with the application of this
technique in the inner Galaxy is the kinematic distance ambiguity. In this
work, we aim to resolve the kinematic distance ambiguity towards a sample of
6.7 GHz methanol masers, which are signposts of the early stages of massive
star formation. We measured 21 cm HI absorption spectra using the Very Large
Array in C and CnB configurations. A comparison of the maximum velocity of HI
absorption with the source velocity and tangent point velocity was used to
resolve the kinematic distance ambiguity. We resolved the distance ambiguity
towards 41 sources. Distance determinations that are in conflict with previous
measurements are discussed. The NE2001 spiral arm model is broadly consistent
with the locations of the star forming complexes. We find that the use of
vertical scale height arguments to resolve the distance ambiguity can lead to
erroneous classifications for a significant fraction of sources.


title: Solitons and vortices in honeycomb defocusing photonic lattices

abstract:
  Solitons and necklaces in the first band-gap of a two-dimensional optically
induced honeycomb defocusing photonic lattice are theoretically considered. It
is shown that dipoles, soliton necklaces, and vortex necklaces exist and may
possess regions of stable propagation through a photorefractive crystal. Most
of the configurations disappear in bifurcations close to the upper edge of the
first band. Solutions associated with such bifurcations are also numerically
examined, and it is found that they are often asymmetric and more exotic. The
dynamics of the relevant unstable structures are also examined through direct
numerical simulations revealing either breathing oscillations or, in some
cases, destruction of the original waveform.


title:
Properties of the Galactic population of cataclysmic variables in hard
  X-rays

abstract:
  We measure the spatial distribution and hard X-ray luminosity function of
cataclysmic variables (CVs) using the INTEGRAL all-sky survey in the 17-60 keV
energy band. The vast majority of the INTEGRAL detected CVs are intermediate
polars with luminosities in the range 10^{32}-10^{34} erg/sec. The scale height
of the Galactic disk population of CVs is found to be 130{+90}{-50} pc. The CV
luminosity function measured with INTEGRAL in hard X-rays is compatible with
that previously determined at lower energies (3--20 keV) using a largely
independent sample of sources detected by RXTE (located at |b|>10deg as opposed
to the INTEGRAL sample, strongly concentrated to the Galactic plane). The
cumulative 17-60 keV luminosity density of CVs per unit stellar mass is found
to be (1.3+/-0.3)x10^{27} erg/sec/Msun and is thus comparable to that of
low-mass X-ray binaries in this energy band. Therefore, faint but numerous CVs
are expected to provide an important contribution to the cumulative hard X-ray
emission of galaxies.


title:
Pressure and Ionization Balances in the Circum-Heliospheric Interstellar
  Medium and the Local Bubble

abstract:
  A disconcerting mismatch of thermal pressures for two media in contact with
each other, (1) the warm, Circum-heliospheric Interstellar Medium (CHISM) and
(2) the very hot material within a much larger region called the Local Bubble
(LB), has troubled astronomers for over two decades. A possible resolution of
this problem, at least in part, now seems possible. We now understand that
earlier estimates for the average electron density in the very hot LB plasma
were inflated by an unrecognized foreground contamination to the low energy
diffuse X-ray background measurements. This foreground illumination arises from
photons emitted by charge exchange reactions between solar wind ions and
neutral atoms from the interstellar medium that enter into the heliosphere.
However, with the resolution of this problem comes a new one. The high
ionization fraction of helium in the CHISM, relative to that of hydrogen, could
be understood in terms of the effects from a strong flux of EUV and X-ray
radiation coming from both the Local Bubble and a conductive interface around
the CHISM. A revision of this interpretation may now be in order, now that the
photoionization rate from radiation emitted by hot gas the Local Bubble is
lower than previously assumed.


title: An authentication scheme based on the twisted conjugacy problem

abstract:
  The conjugacy search problem in a group $G$ is the problem of recovering an
$x \in G$ from given $g \in G$ and $h=x^{-1}gx$. The alleged computational
hardness of this problem in some groups was used in several recently suggested
public key exchange protocols, including the one due to Anshel, Anshel, and
Goldfeld, and the one due to Ko, Lee et al. Sibert, Dehornoy, and Girault used
this problem in their authentication scheme, which was inspired by the
Fiat-Shamir scheme involving repeating several times a three-pass
challenge-response step.
  In this paper, we offer an authentication scheme whose security is based on
the apparent hardness of the twisted conjugacy search problem, which is: given
a pair of endomorphisms (i.e., homomorphisms into itself) phi, \psi of a group
G and a pair of elements w, t \in G, find an element s \in G such that t =
\psi(s^{-1}) w \phi(s) provided at least one such s exists. This problem
appears to be very non-trivial even for free groups. We offer here another
platform, namely, the semigroup of all 2x2 matrices over truncated one-variable
polynomials over F_2, the field of two elements, with transposition used
instead of inversion in the equality above.


title: Ferromagnetic tendency at the surface of CE charge-ordered manganites

abstract:
  Most previous investigations have shown that the surface of a ferromagnetic
material may have antiferromagnetic tendencies. However, experimentally the
opposite effect has been recently observed: ferromagnetism appears in some
nano-sized manganites with a composition such that the antiferromagnetic
charge-ordered CE state is observed in the bulk. A possible origin is the
development of ferromagnetic correlations at the surface of these small
systems. To clarify these puzzling experimental observations, we have studied
the two-orbital double-exchange model near half-doping n=0.5, using open
boundary conditions to simulate the surface of either bulk or nano-sized
manganites. Considering the enhancement of surface charge density due to a
possible AO termination (A = trivalent/divalent ion composite, O = oxygen), an
unexpected surface phase-separated state emerges when the model is studied
using Monte Carlo techniques on small clusters. This tendency suppresses the CE
charge ordering and produces a weak ferromagnetic signal that could explain the
experimental observations.


title:
On the Dynamical Generation of Quark-Level-Linear-Sigma-Model-like
  Theories beyond one Loop

abstract:
  A self-consistent strategy to complete the dynamical generation of
Quark-Level-Linear-Sigma-Model-like Lagrangean theories beyond one loop as
proposed in more detail in our manuscript arXiv:0802.1540 [hep-ph] is shortly
outlined.


title:
QQ-onia package: a numerical solution to the Schrodinger radial equation
  for heavy quarkonium

abstract:
  This paper presents the basics of the QQ-onia package, a software based upon
the Numerov method which can be used to solve the Schrodinger radial equation
using a suitable potential V(r) for the heavy quarkonium system. This package
also allows the analysis of relevant properties of those resonances such as the
wave functions at the origin, their corresponding derivatives for l \neq 0
states, typical heavy quark velocities, and mean square radii. Besides, it
includes a tool to analize the spin-dependent contributions to the heavy
quarkonia spectrum, providing the hyperfine splittings, as well as the nPJ
energy levels. Finally, a simple software implemented in QQ-onia to compute E1
transition rates is presented.


title:
Three-dimensional Random Voronoi Tessellations: From Cubic Crystal
  Lattices to Poisson Point Processes

abstract:
  We perturb the SC, BCC, and FCC crystal structures with a spatial Gaussian
noise whose adimensional strength is controlled by the parameter a, and analyze
the topological and metrical properties of the resulting Voronoi Tessellations
(VT). The topological properties of the VT of the SC and FCC crystals are
unstable with respect to the introduction of noise, because the corresponding
polyhedra are geometrically degenerate, whereas the tessellation of the BCC
crystal is topologically stable even against noise of small but finite
intensity. For weak noise, the mean area of the perturbed BCC and FCC crystals
VT increases quadratically with a. In the case of perturbed SCC crystals, there
is an optimal amount of noise that minimizes the mean area of the cells.
Already for a moderate noise (a>0.5), the properties of the three perturbed VT
are indistinguishable, and for intense noise (a>2), results converge to the
Poisson-VT limit. Notably, 2-parameter gamma distributions are an excellent
model for the empirical of of all considered properties. The VT of the
perturbed BCC and FCC structures are local maxima for the isoperimetric
quotient, which measures the degre of sphericity of the cells, among space
filling VT. In the BCC case, this suggests a weaker form of the recentluy
disproved Kelvin conjecture. Due to the fluctuations of the shape of the cells,
anomalous scalings with exponents >3/2 is observed between the area and the
volumes of the cells, and, except for the FCC case, also for a->0. In the
Poisson-VT limit, the exponent is about 1.67. As the number of faces is
positively correlated with the sphericity of the cells, the anomalous scaling
is heavily reduced when we perform powerlaw fits separately on cells with a
specific number of faces.

categories: cond-mat.stat-mech cond-mat.dis-nn cond-mat.other cs.CG math-ph math.MP nlin.PS physics.data-an


title: Effect of spin diffusion on spin torque in magnetic nanopillars

abstract:
  We present systematic magnetoelectronic measurements of magnetic nanopillars
with different structures of polarizing magnetic layers. The magnetic reversal
at small magnetic field, the onset of magnetic dynamics at larger field, and
the magnetoresistance exhibit a significant dependence on the type of the
polarizing layer. We performed detailed quantitative modeling showing that the
differences can be explained by the effects of spin-dependent electron
diffusion.


title: Recurrence Formulas for Fibonacci Sums

abstract:
  In this article we present a new recurrence formula for a finite sum
involving the Fibonacci sequence. Furthermore, we state an algorithm to compute
the sum of a power series related to Fibonacci series, without the use of
term-by-term differentiation theorem


title: Modulation transfer spectroscopy in atomic rubidium

abstract:
  We report modulation transfer spectroscopy on the D2 transitions in 85Rb and
87Rb using a simple home-built electro-optic modulator (EOM). We show that both
the gradient and amplitude of modulation transfer spectroscopy signals, for the
87Rb F=2 to F'=3 and the 85Rb F=3 to F'=4 transitions, can be significantly
enhanced by expanding the beams, improving the signals for laser frequency
stabilization. The signal gradient for these transitions is increased by a
factor of 3 and the peak to peak amplitude was increased by a factor of 2. The
modulation transfer signal for the 85Rb F=2 to F' transitions is also presented
to highlight how this technique can generate a single, clear line for laser
frequency stabilization even in cases where there are a number of closely
spaced hyperfine transitions.


title: Cops and robbers in random graphs

abstract:
  We consider the pursuit and evasion game on finite, connected, undirected
graphs known as cops and robbers. Meyniel conjectured that for every graph on n
vertices a rootish number of cops can win the game. We prove that this holds up
to a log(n) factor for random graphs G(n,p) if p is not very small, and this is
close to be tight unless the graph is very dense. We analyze the area-defending
strategy (used by Aigner in case of planar graphs) and show examples where it
can not be too efficient.


title: Observable invariant measures

abstract:
  For continuous maps on a compact manifold M, particularly for those that do
not preserve the Lebesgue measure m, we define the observable invariant
probability measures as a generalization of the physical measures. We prove
that any continuous map has observable measures, and characterize those that
are physical in terms of the observability. We prove that there exist physical
measures whose basins cover Lebesgue a.e, if and only if the set of all
observable measures is finite or infinite numerable. We define for any
continuous map, its generalized attractors using the set of observable
invariant measures where there is no physical measure, and prove that any
continuous map defines a decomposition of the space in up to infinitely many
generalized attractors whose basins cover Lebesgue a.e. We apply the results to
the C1 expanding maps f in the circle, proving that the set of observable
measures (even if f is not C1 plus Holder, is a subset of the equilibrium
states.


title:
Multi-bump Solutions for a Strongly Indefinite Semilinear Schr\"odinger
  Equation Without Symmetry or convexity Assumptions

abstract:
  In this paper, we study the following semilinear Schr\"odinger equation with
periodic coefficient: $$-\triangle u +V(x)u=f(x,u), u\in
H^{1}(\mathbb{R}^{N}).$$ The functional corresponding to this equation
possesses strongly indefinite structure. The nonlinear term $f(x,t)$ satisfies
some superlinear growth conditions and need not be odd or increasing strictly
in $t$. Using a new variational reduction method and a generalized Morse
theory, we proved that this equation has infinitely many geometrically
different solutions. Furthermore, if the solutions of this equation under some
energy level are isolated, then we can show that this equation has infinitely
many $m-$bump solutions for any positive integer $m\geq 2.$


title:
Evolution of neutron stars with toroidal magnetic fields: Axisymmetric
  simulation in full general relativity

abstract:
  We study the stability of neutron stars with toroidal magnetic fields by
magnetohydrodynamic simulation in full general relativity under assumption of
axial symmetry. Nonrotating and rigidly rotating neutron stars are prepared for
a variety of magnetic field configuration. For modeling the neutron stars, the
polytropic equation of state with the adiabatic index $\Gamma=2$ is used for
simplicity. It is found that nonrotating neutron stars are dynamically unstable
for the case that toroidal magnetic field strength varies $\propto
\varpi^{2k-1}$ with $k\geq 2$ (here $\varpi$ is the cylindrical radius),
whereas for $k=1$ the neutron stars are stable. After the onset of the
instability, unstable modes grow approximately in the Alfv\'en time scale and,
as a result, a convective motion is excited to change the magnetic field
profile until a new state, which is stable against axisymmetric perturbation,
is reached. We also find that rotation plays a role in stabilization, although
the instability still sets in in the Alfv\'en time scale when the ratio of
magnetic energy to rotational kinetic energy is larger than a critical value
$\sim 0.2$. Implication for the evolution of magnetized protoneutron stars is
discussed.


title:
Coherence-based multivariate analysis of high frequency stock market
  values

abstract:
  The paper tackles the problem of deriving a topological structure among stock
prices from high frequency historical values. Similar studies using low
frequency data have already provided valuable insights. However, in those cases
data need to be collected for a longer period and then they have to be
detrended. An effective technique based on averaging a metric function on short
subperiods of the observation horizon is suggested. Since a standard
correlation-based metric is not capable of catching dependencies at different
time instants, it is not expected to perform the best when dealing with high
frequency data. Hence, the choice of a more suitable metric is discussed. In
particular, a coherence-based metric is proposed, for it is able to detect any
possible linear relation between two times series, even at different time
instants. The averaging technique is employed to analyze a set of 100 high
volume stocks of the New York Stock Exchange, observed during March 2008.


title:
Topological Quantum Computation by Manipulating Quantum Tunneling Effect
  of the Toric Codes

abstract:
  Quantum computers are predicted to utilize quantum states to perform memory
and to process tasks far faster than those of conventional classical computers.
In this paper we show a new road towards building fault tolerance quantum
computer by tuning quantum tunneling effect of the degenerate quantum states in
topological order, instead of by braiding anyons. Using a designer Hamiltonian
- the Wen-Plaquette model as an example, we study its quantum tunneling effect
of the toric codes and show how to control the toric code to realize
topological quantum computation (TQC). In particular, we give a proposal to the
measurement of TQC. In the end the realization of the Wen-Plaquette model in
cold atoms is discussed.


title:
The Aharonov-Bohm-Casher ring-dot as a flux-tunable resonant tunneling
  diode

abstract:
  A mesoscopic ring subject to the Rashba spin-orbit interaction and
sequentially coupled to an interacting quantum dot, in the presence of
Aharonov-Bohm flux, is proposed as a flux tunable tunneling diode. The analysis
of the conductance by means of the nonequilibrium Green's function technique,
shows an intrinsic bistability at varying the Aharonov-Bohm flux when 2U > \pi
\Gamma, U being the charging energy on the dot and \Gamma the effective
resonance width. The bistability properties are discussed in connection with
spin-switch effects and logical storage device applications.


title: Tunnel spectroscopy in ac-driven quantum dot nanoresonators

abstract:
  Electronic transport in a triple quantum dot shuttle device in the presence
of an ac field is analyzed within a fully quantum mechanical framework. A
generalized density matrix formalism is used to describe the time evolution for
electronic state occupations in a dissipative phonon bath. In the presence of
an ac gate voltage, the electronic states are dressed by photons and the
interplay between photon and vibrational sidebands produces current
characteristics that obey selection rules. Varying the ac parameters allows to
tune the tunneling current features. In particular, we show that coherent
destruction of tunneling can be achieved in our device.


title: Core-collapse supernova neutrinos and neutrino properties

abstract:
  Core-collapse supernovae are powerful neutrino sources. The observation of a
future (extra-)galactic supernova explosion or of the relic supernova neutrinos
might provide important information on the supernova dynamics, on the supernova
formation rate and on neutrino properties. One might learn more about unknown
neutrino properties either from indirect effects in the supernova (e.g. on the
explosion or on in the r-process) or from modifications of the neutrino time or
energy distributions in a detector on Earth. Here we will discuss in particular
possible effects of CP violation in the lepton sector. We will also mention the
interest of future neutrino-nucleus interaction measurements for the precise
knowledge of supernova neutrino detector response to electron neutrinos.


title:
On Indefinite Special Lagrangian Submanifolds in Indefinite Complex
  Euclidean Spaces

abstract:
  In this paper, we show that the calibrated method can also be used to detect
indefinite minimal Lagrangian submanifolds in $C_k^m$. We introduce the notion
of indefinite special Lagrangian submanifolds in $C_k^m$ and generalize the
well-known work of Harvey-Lawson to the indefinite case.


title: Magnetism of Cold Fermionic Atoms on p-Band of an Optical Lattice

abstract:
  We carry out \textit{ab initio} study of ground state phase diagram of
spin-1/2 cold fermionic atoms within two-fold degenerate $p$-band of an
anisotropic optical lattice. Using the Gutzwiller variational approach, we show
that a robust ferromagnetic phase exists for a vast range of band fillings and
interacting strengths. The ground state crosses over from spin density wave
state to spin-1 Neel state at half filling. Additional harmonic trap will
induce spatial separation of varies phases. We also discuss several relevant
observable consequences and detection methods. Experimental test of the results
reported here may shed some light on the long-standing issue of itinerant
ferromagnetism.


title:
Local solutions in Sobolev spaces with negative indices for the "good"
  Boussinesq equation

abstract:
  We study the local well-posedness of the initial-value problem for the
nonlinear "good" Boussinesq equation with data in Sobolev spaces \textit{$H^s$}
for negative indices of $s$.


title: Rotational parameters of strange stars in comparison with neutron stars

abstract:
  I study stellar structures $i.e.$ the mass, the radius, the moment of inertia
and the oblateness parameter at different spin frequencies for strange stars
and neutron stars in a comparative manner. I also calculate the values of the
radii of the marginally stable orbits and Keplerian orbital frequencies. By
equating kHz QPO frequencies to Keplerian orbital frequencies, I find
corresponding orbital radii. Knowledge about these parameters might be useful
in further modeling of the observed features from LMXBs with advanced and
improved future techniques for observations and data analysis.


title: CW-groups associated with wrap groups

abstract:
  This article is devoted to the investigation of wrap groups of connected
fiber bundles. CW-groups associated with wrap groups are studied.


title: Efficient $6j$ symbol evaluations for atomic calculations

abstract:
  We have developed an efficient tabulation scheme to evaluate $6j$ symbol for
atomic calculations. The scheme is appropriate for coupled-cluster based
calculations. In particular, for perturbed coupled-clusters calculations, which
has another perturbation in addition to the residual Coulomb interaction. The
scheme relies on the symmetry of the $6j$ symbol and the triangular conditions.


title:
Chandra HETG line spectroscopy of the Non-magnetic Cataclysmic Variable
  SS Cyg

abstract:
  We present {\it Chandra} HETG observations of SS Cygni in quiescence and
outburst. The spectra are characterized by He-like and H-like Ka emission lines
from O to Fe, as well as L-shell emission lines from Fe. In quiescence, the
spectra are dominated by the H-like Ka lines, whereas in outburst the He-like
lines are as intense as the H-like lines. In outburst, the H-like Ka lines from
O to Si are broad, with widths of 4--14 eV in Gaussian $\sigma$ (1800--2300$
{\rm km s^{-1}}$). The large line widths, together with line profiles, indicate
that the line-emitting plasma is associated with the Keplerian disk and still
retains the azimuthal bulk motion. In quiescence, the emission lines are
narrower, with a Gaussian $\sigma$ of 1--3 eV (420--620$ {\rm km s^{-1}}$). A
slightly larger velocity for lighter elements suggests that the lines in
quiescence are emitted from an ionizing plasma at the entrance of the boundary
layer, where the bulk motion of the optically thick accretion disk is converted
into heat due to friction. Using the line intensity ratio of He-like and H-like
Ka lines for each element, we have also investigated the temperature
distribution in the boundary layer both in quiescence and outburst. The
distribution of SS Cyg is found to be consistent with other dwarf novae
investigated systematically with {\it ASCA} data.


title:
Physics-based mathematical models for quantum devices via experimental
  system identification

abstract:
  We consider the task of intrinsic control system identification for quantum
devices. The problem of experimental determination of subspace confinement is
considered, and simple general strategies for full Hamiltonian identification
and decoherence characterization of a controlled two-level system are
presented.


title:
Superfluidity at the BEC-BCS crossover in two-dimensional Fermi gases
  with population and mass imbalance

abstract:
  We explore the zero temperature phase behavior of a two-dimensional
two-component atomic Fermi gas with population and mass imbalance in the regime
of the BEC-BCS crossover. Working in the mean-field approximation, we show that
the normal and homogeneous balanced superfluid phases are separated by an
inhomogeneous superfluid phase of Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) type.
We obtain an analytical expression for the line of continuous transitions
separating the normal and inhomogeneous FFLO phases. We further show that the
transition from the FFLO phase to the homogeneous balanced superfluid is
discontinuous leading to phase separation. If the species have different
masses, the superfluid phase is favored when the lighter species is in excess.
We explore the implications of these findings for the properties of the
two-component Fermi gas in the atomic trap geometry. Finally, we compare and
contrast our findings with the predicted phase behavior of the electron-hole
bilayer system.


title:
A novel active quenching circuit for single photon detection with Geiger
  mode avalanche photodiodes

abstract:
  In this paper we present a novel construction of an active quenching circuit
intended for single photon detection. For purpose of evaluation, we have
combined this circuit with a standard avalanche photodiode C30902S to form a
single photon detector. A series of measurements, presented here, show that
this single photon detector has a dead time of less than 40ns, maximum random
counting frequency of over 14MHz, low after pulsing, detection efficiency of
over 20% and a good noise performance. This simple and robust active quenching
circuit can be built from of-the-shelf electronic components and needs no
complicated adjustments.


title:
Progress in Developing Hybrid RPCs: GEM-like Detectors with Resistive
  Electrodes

abstract:
  We have recently developed an innovative detector of photons and charged
particles: a GEM-like gaseous amplification structure with resistive electrodes
instead of commonly used metallic ones. This novel detector combines the best
property of GEMs- the capability to operate in a cascaded mode and in poorly
quenched gases - and of RPC: the protection against sparks. In this paper will
shortly review our latest achievements in this direction, however the main
focus will be given on a new advanced design that allows to build large area
detectors manufactured by a screen printing technology. The proposed detector,
depending on the applications, can operate either in a GEM mode (electron
multiplications through holes only) or as a hybrid RPC with simultaneous
amplifications in the drift region and in the holes. The possible applications
of this new detector will be discussed.