title: Controlled switching of N\'eel caps in flux-closure magnetic dots

abstract:
  While magnetic hysteresis usually considers magnetic domains, the switching
of the core of magnetic vortices has recently become an active topic. We
considered Bloch domain walls, which are known to display at the surface of
thin films flux-closure features called N\'eel caps. We demonstrated the
controlled switching of these caps under a magnetic field, occurring via the
propagation of a surface vortex. For this we considered flux-closure states in
elongated micron-sized dots, so that only the central domain wall can be
addressed, while domains remain unaffected.


title: Defining the Termination of the Asymptotic Giant Branch

abstract:
  I suggest a theoretical quantitative definition for the termination of the
asymptotic giant branch (AGB) phase and the beginning of the post-AGB phase. I
suggest that the transition will be taken to occur when the ratio of the
dynamical time scale to the the envelope thermal time scale, Q, reaches its
maximum value. Time average values are used for the different quantities, as
the criterion does not refer to the short time-scale variations occurring on
the AGB and post-AGB, e.g., thermal pulses (helium shell flashes) and magnetic
activity. Along the entire AGB the value of Q increases, even when the star
starts to contract. Only when a rapid contraction starts does the value of Q
start to decrease. This criterion captures the essence of the transition from
the AGB to the post AGB phase, because Q is connected to the stellar effective
temperature, reaching its maximum value at T~4000-6000 K, it is related to the
mass loss properties, and it reaches its maximum value when rapid contraction
starts and envelope mass is very low.


title: The well-ordering of dual braid monoids

abstract:
  We describe the restriction of the Dehornoy ordering of braids to the dual
braid monoids introduced by Birman, Ko and Lee: we give an inductive
characterization of the ordering of the dual braid monoids and compute the
corresponding ordinal type. The proof consists in introducing a new ordering on
the dual braid monoid using the rotating normal form of arXiv:0811.3902
[math.GR], and then proving that this new ordering coincides with the standard
ordering of braids.


title: On the convergence to the multiple Wiener-Ito integral

abstract:
  We study the convergence to the multiple Wiener-It\^{o} integral from
processes with absolutely continuous paths. More precisely, consider a family
of processes, with paths in the Cameron-Martin space, that converges weakly to
a standard Brownian motion in $\mathcal C_0([0,T])$. Using these processes, we
construct a family that converges weakly, in the sense of the finite
dimensional distributions, to the multiple Wiener-It\^{o} integral process of a
function $f\in L^2([0,T]^n)$. We prove also the weak convergence in the space
$\mathcal C_0([0,T])$ to the second order integral for two important families
of processes that converge to a standard Brownian motion.


title: General Transformation Formulas for Fermi-Walker Coordinates

abstract:
  We calculate the transformation and inverse transformation, in the form of
Taylor expansions, from arbitrary coordinates to Fermi-Walker coordinates in
tubular neighborhoods of arbitrary timelike paths for general spacetimes.
Explicit formulas for coefficients and the Jacobian matrix are given.


title: Search for Theta+ via K+p -> pi+X reaction with a 1.2 GeV/c K+ beam

abstract:
  The Theta+ was searched for via the K+p -> pi+X reaction using the 1.2 GeV/c
K+ beam at the K6 beam line of the KEK-PS 12 GeV Proton Synchrotron. In the
missing mass spectrum of the K+p -> pi+X reaction, no clear peak structure was
observed. Therefore a 90 % C.L. upper limit of 3.5 ub/sr was derived for the
differential cross section averaged over 2degree to 22degree in the laboratory
frame of the K+p -> pi+Theta+ reaction. This upper limit is much smaller than
the theoretical calculation for the t-channel process where a K0* is exchanged.
  From the present result, either the t-channel process is excluded or the
coupling constant of g_{K*N\Theta} is quite small.


title: Invertible harmonic mappings, beyond Kneser

abstract:
  We prove necessary and sufficient criteria of invertibility for planar
harmonic mappings which generalize a classical result of H. Kneser, also known
as the Rad\'{o}-Kneser-Choquet theorem.


title:
Measurement of the absolute branching ratios for semileptonic K+/-
  decays with the KLOE detector

abstract:
  Using a sample of over 600 million phi->K+K- decays collected at the Dafne
e+e- collider, we have measured with the KLOE detector the absolute branching
ratios for the charged kaon semileptonic decays, K+/- -> p0 e nu (gamma) (Ke3)
and K+/- -> p0 mu nu (gamma) (Kmu3). The results, BR(Ke3) = 0.04965 +/-
0.00038_{stat} +/- 0.00037_{syst} and BR(Kmu3) = 0.03233 +/- 0.00029_{stat} +/-
0.00026_{syst}, are inclusive of radiation. Accounting for correlations, we
derive the ratio Kmu3/Ke3 = 0.6511+/-0.0064. Using the semileptonic form
factors measured in the same experiment, we obtain V_{us}f_{+}(0) = 0.2141 +/-
0.0013.


title: Experimental observation of a complex periodic window

abstract:
  The existence of a special periodic window in the two-dimensional parameter
space of an experimental Chua's circuit is reported. One of the main reasons
that makes such a window special is that the observation of one implies that
other similar periodic windows must exist for other parameter values. However,
such a window has never been experimentally observed, since its size in
parameter space decreases exponentially with the period of the periodic
attractor. This property imposes clear limitations for its experimental
detection.


title: Cyclic Evolution on Grassmann Manifold and Berry Phase

abstract:
  For a given $k$-dimensional subspace $V_0$ in a Hilbert space $\hilb$ and a
unitary transformation $g_0:V_0\To V_0$, we find a path in the Grassmann
manifold the monodromy of which coincides with $g_0$.


title:
Supersymmetric field theory of local light diffusion in semi-infinite
  media

abstract:
  A supersymmetric field theory of light diffusion in semi-infinite disordered
media is presented. With the help of this technique we justify--at the
perturbative level--the local light diffusion proposed by Tiggelen, Lagendijk,
and Wiersma [Phys. Rev. Lett. \textbf{84}, 4333 (2000)], and show that the
coherent backscattering line shape of medium bar displays a crossover from
two-dimensional weak to quasi-one-dimensional strong localization.


title: Acceleration of dust particles by low-frequency Alfv\'en waves

abstract:
  We investigate the efficiency of acceleration of charged dust particles by
low-frequency Alfv\'en waves in nonlinear approximation. We show that the
longitudinal acceleration of dust particles is proportional to the square of
the soliton amplitude $O(|b_m|^2)$, while the transversal acceleration is of
$O(|b_m|)$. In the conditions of the interstellar medium the resulting velocity
of dust particles can reach 0.3 to 1 km s$^{-1}$.


title: On Mason's rigidity theorem

abstract:
  Following an argument proposed by Mason, we prove that there are no
algebraically special asymptotically simple vacuum space-times with a smooth,
shear-free, geodesic congruence of principal null directions extending
transversally to a cross-section of Scri. Our analysis leaves the door open for
escaping this conclusion if the congruence is not smooth, or not transverse to
Scri. One of the elements of the proof is a new rigidity theorem for the
Trautman-Bondi mass.


title: Random and Integrable Models in Mathematics and Physics

abstract:
  This set of Montreal lectures is an elementary and sketchy introduction to
the general field of random matrices. The first half is devoted to
combinatorial models, whereas the second half deals with random matrix
questions(GUE, etc...).


title:
Hierarchy wave functions--from conformal correlators to Tao-Thouless
  states

abstract:
  Laughlin's wave functions, describing the fractional quantum Hall effect at
filling factors $\nu=1/(2k+1)$, can be obtained as correlation functions in
conformal field theory, and recently this construction was extended to Jain's
composite fermion wave functions at filling factors $\nu=n/(2kn+1)$. Here we
generalize this latter construction and present ground state wave functions for
all quantum Hall hierarchy states that are obtained by successive condensation
of quasielectrons (as opposed to quasiholes) in the original hierarchy
construction. By considering these wave functions on a cylinder, we show that
they approach the exact ground states, the Tao-Thouless states, when the
cylinder becomes thin. We also present wave functions for the multi-hole
states, make the connection to Wen's general classification of abelian quantum
Hall fluids, and discuss whether the fractional statistics of the
quasiparticles can be analytically determined. Finally we discuss to what
extent our wave functions can be described in the language of composite
fermions.


title:
Entangled Photon-Electron States and the Number-Phase Minimum
  Uncertainty States of the Photon Field

abstract:
  The exact analytic solutions of the energy eigenvalue equation of the system
consisting of a free electron and one mode of the quantized radiation field are
used for studying the physical meaning of a class of number-phase minimum
uncertainty states. The states of the mode which minimize the uncertainty
product of the photon number and the Susskind and Glogower (1964) cosine
operator have been obtained by Jackiw (1968). However, these states have so far
been remained mere mathematical constructions without any physical
significance. It is proved that the most fundamental interaction in quantum
electrodynamics - namely the interaction of a free electron with a mode of the
quantized radiation field - leads quite naturally to the generation of the
mentioned minimum uncertainty states. It is shown that from the entangled
photon-electron states developing from a highly excited number state, due to
the interaction with a Gaussian electronic wave packet, the minimum uncertainty
states of Jackiw's type can be constructed. In the electron's coordinate
representation the physical meaning of the expansion coefficients of these
states are the joint probability amplitudes of simultaneous detection of an
electron and of a definite number of photons. The joint occupation
probabilities in these states preserve their functional form as time elapses,
but they vary from point to point in space-time, depending on the location of
the detected electron. An analysis of the entanglement entropies derived from
the photon number distribution and from the electron's density operator is
given.


title: Fermat's Four Squares Theorem

abstract:
  It is easy to find a right-angled triangle with integer sides whose area is
6. There is no such triangle with area 5, but there is one with rational sides
(a `\emph{Pythagorean triangle}').
  For historical reasons, integers such as 6 or 5 that are (the squarefree part
of) the area of some Pythagorean triangle are called `\emph{congruent
numbers}'. These numbers actually are interesting for the following reason:
Notice the sequence $\frac14$, $6\frac14$, $12\frac14$. It is an arithmetic
progression with common difference 6, consisting of squares $(\frac12)^2$,
$(\frac52)^2$, $(\frac72)^2$ of rational numbers. Indeed the common difference
of three rational squares in AP is a congruent number and every congruent
number is the common difference of three rational squares in arithmetic
progression.
  The triangle given by $9^{2}+40^{2}=41^{2}$ has area $180=5\cdot6^{2}$ and
the numbers $x-5$, $x$ and $x+5$ all are rational squares if $x=11{97/144}$.
Recall one obtains all Pythagorean triangles with relatively prime integer
sides by taking $x=4uv$, $y=\pm(4u^{2}-v^{2})$, $z=4u^{2}+v^{2}$ where $u$ and
$v$ are integers with $2u$ and $v$ relatively prime.
  Fermat proved that there is no AP of more than three squares of rationals.


title: Nonlinear behavior of bosons in anisotropic optical lattices

abstract:
  We investigate the behavior of an array of Bose-Einstein condensate tubes
described by means of a Bose-Hubbard Hamiltonian. Using an anisotropic
non-polynomial Schrodinger equation we link the macroscopic parameters in the
Bose-Hubbard Hamiltonian to the ones that are tunable in experiments. Using a
mean field approach we predict that increasing the optical lattice strength
along the direction of the tubes, the condensate can experience a reentrant
transition between a Mott insulating phase and the superfluid one.


title: From Data to Probability Densities without Histograms

abstract:
  When one deals with data drawn from continuous variables, a histogram is
often inadequate to display their probability density. It deals inefficiently
with statistical noise, and binsizes are free parameters. In contrast to that,
the empirical cumulative distribution function (obtained after sorting the
data) is parameter free. But it is a step function, so that its differentiation
does not give a smooth probability density. Based on Fourier series expansion
and Kolmogorov tests, we introduce a simple method, which overcomes this
problem. Error bars on the estimated probability density are calculated using a
jackknife method. We give several examples and provide computer code
reproducing them. You may want to look at the corresponding figures 4 to 9
first.

categories: physics.data-an cond-mat.stat-mech hep-lat physics.comp-ph


title: The Rayleigh-Taylor instability and internal waves in quantum plasmas

abstract:
  Influence of quantum effects on the internal waves and the Rayleigh-Taylor
instability in plasma is investigated. It is shown that quantum pressure always
stabilizes the RT instability. The problem is solved both in the limit of
short-wavelength perturbations and exactly for density profiles with layers of
exponential stratification. In the case of stable stratification, quantum
pressure modifies the dispersion relation of the inertial waves. Because of the
quantum effects, the internal waves may propagate in the transverse direction,
which was impossible in the classical case. A specific form of pure quantum
internal waves is obtained, which do not require any external gravitational
field.


title: Twisted flux tube emergence from the convection zone to the corona

abstract:
  3D numerical simulations of a horizontal magnetic flux tube emergence with
different twist are carried out in a computational domain spanning the upper
layers of the convection zone to the lower corona. We use the Oslo Staggered
Code to solve the full MHD equations with non-grey and non-LTE radiative
transfer and thermal conduction along the magnetic field lines. The emergence
of the magnetic flux tube input at the bottom boundary into a weakly magnetized
atmosphere is presented. The photospheric and chromospheric response is
described with magnetograms, synthetic images and velocity field distributions.
The emergence of a magnetic flux tube into such an atmosphere results in varied
atmospheric responses. In the photosphere the granular size increases when the
flux tube approaches from below. In the convective overshoot region some 200km
above the photosphere adiabatic expansion produces cooling, darker regions with
the structure of granulation cells. We also find collapsed granulation in the
boundaries of the rising flux tube. Once the flux tube has crossed the
photosphere, bright points related with concentrated magnetic field, vorticity,
high vertical velocities and heating by compressed material are found at
heights up to 500km above the photosphere. At greater heights in the magnetized
chromosphere, the rising flux tube produces a cool, magnetized bubble that
tends to expel the usual chromospheric oscillations. In addition the rising
flux tube dramatically increases the chromospheric scale height, pushing the
transition region and corona aside such that the chromosphere extends up to 6Mm
above the photosphere. The emergence of magnetic flux tubes through the
photosphere to the lower corona is a relatively slow process, taking of order 1
hour.


title:
Near-Infrared observations of the type Ib Supernova SN2006jc: evidence
  of interactions with dust

abstract:
  In the framework of a program for the monitoring of Supernovae in the
Near-Infrared (NIR) carried out by the Teramo, Rome and Pulkovo observatories
with the AZT-24 telescope, we observed the Supernova SN2006jc in the J,H,K
photometric bands during a period of 7 months, starting ~36 days after its
discovery. Our observations evidence a NIR re-brightening, peaking ~70 days
after discovery, along with a reddening of H-K and J-H colors until 120 days
from discovery. After that date, J-H seems to evolve towards bluer colors. Our
data, complemented by IR, optical, UV and X-ray observations found in the
literature, show that the re-brightening is produced by hot dust surrounding
the supernova, formed in the interaction of the ejecta with dense circumstellar
matter.


title: Topics in Special Functions

abstract:
  The authors survey recent results in special functions, particularly the
gamma function and the Gaussian hypergeometric function.


title: String topology for stacks

abstract:
  We establish the general machinery of string topology for differentiable
stacks. This machinery allows us to treat on an equal footing free loops in
stacks and hidden loops. In particular, we give a good notion of a free loop
stack, and of a mapping stack $\map(Y,\XX)$, where $Y$ is a compact space and
$\XX$ a topological stack, which is functorial both in $\XX$ and $Y$ and
behaves well enough with respect to pushouts. We also construct a bivariant (in
the sense of Fulton and MacPherson) theory for topological stacks: it gives us
a flexible theory of Gysin maps which are automatically compatible with
pullback, pushforward and products. Further we prove an excess formula in this
context. We introduce oriented stacks, generalizing oriented manifolds, which
are stacks on which we can do string topology. We prove that the homology of
the free loop stack of an oriented stack and the homology of hidden loops
(sometimes called ghost loops) are a Frobenius algebra which are related by a
natural morphism of Frobenius algebras. We also prove that the homology of free
loop stack has a natural structure of a BV-algebra, which together with the
Frobenius structure fits into an homological conformal field theories with
closed positive boundaries. Using our general machinery, we construct an
intersection pairing for (non necessarily compact) almost complex orbifolds
which is in the same relation to the intersection pairing for manifolds as
Chen-Ruan orbifold cup-product is to ordinary cup-product of manifolds. We show
that the hidden loop product of almost complex is isomorphic to the orbifold
intersection pairing twisted by a canonical class. Finally we gave some
examples including the case of the classifying stacks $[*/G]$ of a compact Lie
group.


title: Bottleneck flows in networks

abstract:
  The bottleneck network flow problem (BNFP) is a generalization of several
well-studied bottleneck problems such as the bottleneck transportation problem
(BTP), bottleneck assignment problem (BAP), bottleneck path problem (BPP), and
so on. In this paper we provide a review of important results on this topic and
its various special cases. We observe that the BNFP can be solved as a sequence
of $O(\log n)$ maximum flow problems. However, special augmenting path based
algorithms for the maximum flow problem can be modified to obtain algorithms
for the BNFP with the property that these variations and the corresponding
maximum flow algorithms have identical worst case time complexity. On unit
capacity network we show that BNFP can be solved in $O(\min \{{m(n\log
n)}^{{2/3}}, m^{{3/2}}\sqrt{\log n}\})$. This improves the best available
algorithm by a factor of $\sqrt{\log n}$. On unit capacity simple graphs, we
show that BNFP can be solved in $O(m \sqrt {n \log n})$ time. As a consequence
we have an $O(m \sqrt {n \log n})$ algorithm for the BTP with unit arc
capacities.


title: Classification of $k$-tangle projections using cascade representation

abstract:
  The paper addresses the $k$-tangle enumeration problem. We introduce a notion
of cascade diagram for $k$-tangle projections. An effective enumeration
algorithm for projections is proposed based on cascade representation. Tangles
projections with up to 12 crossings are tabulated. We provide also pictures of
alternating $k$-tangles with 5 crossing or less.


title:
Distribution of the 83Rb/83mKr activity on vacuum evaporated samples
  examined with the Timepix position sensitive detector

abstract:
  Properties of vacuum evaporated 83Rb/83mKr sources of low-energy conversion
electrons, which are under development for monitoring the energy scale
stability of the Karlsruhe Tritium Neutrino experiment KATRIN, were examined by
the Timepix pixel detector exhibiting the position resolution of at least 55
microm. No distinct local inhomogeneities in the surface distribution of
83Rb/83mKr were observed. The source diameter derived from the recorded image
agrees within 5 % with that expected from evaporation geometry. More precise
determination of the actual source diameter is complicated by Compton scattered
electrons caused by 83Rb gamma-rays.


title:
Effect of Multiple Scattering on the Critical Electric Field for Runaway
  Electrons in the Atmosphere

abstract:
  A simple method for taking into account the multiple Coulomb scattering in
construction of a separatrix (the line separating the regions of runaway and
decelerating electrons in an electric field) is described. The desired line is
obtained by solving a simple transcendental equation.


title: Accounting for velocity jitter in planet search surveys

abstract:
  The role of radial velocity (RV) jitter in extrasolar planet search surveys
is discussed. Based on the maximum likelihood principle, improved statistical
algorithms for RV fitting and period search are developed. These algorithms
incorporate a built-in jitter determination, so that resulting estimations of
planetary parameters account for this jitter automatically. This approach is
applied to RV data for several extrasolar planetary systems. It is shown that
many RV planet search surveys suffer from periodic systematic errors which
increase effective RV jitter and can lead to erroneous conclusions. For
instance, the planet candidate HD74156 d may be a false detection made due to
annual systematic errors.


title:
Canonical bundles of complex nilmanifolds, with applications to
  hypercomplex geometry

abstract:
  A nilmanifold is a quotient of a nilpotent group $G$ by a co-compact discrete
subgroup. A complex nilmanifold is one which is equipped with a $G$-invariant
complex structure. We prove that a complex nilmanifold has trivial canonical
bundle. This is used to study hypercomplex nilmanifolds (nilmanifolds with a
triple of $G$-invariant complex structures which satisfy quaternionic
relations). We prove that a hypercomplex nilmanifold admits an HKT (hyperkahler
with torsion) metric if and only if the underlying hypercomplex structure is
abelian. Moreover, any $G$-invariant HKT-metric on a nilmanifold is balanced
with respect to all associated complex structures.


title:
Effective generation of Ising interaction and cluster states in coupled
  microcavities

abstract:
  We propose a scheme for realizing the Ising spin-spin interaction and atomic
cluster states utilizing trapped atoms in coupled microcavities. It is shown
that the atoms can interact with each other via the exchange of virtual photons
of the cavities. Through suitably tuning the parameters, an effective Ising
spin-spin interaction can be generated in this optical system, which is used to
produce the cluster states. This scheme does not need the preparation of
initial states of atoms and cavity modes, and is insensitive to cavity decay.


title: Local smoothing for the backscattering transform

abstract:
  An analysis of the backscattering data for the Schr\"odinger operator in odd
dimensions $n\ge 3$ motivates the introduction of the backscattering transform
$B: C_0^\infty ({\mathbb R}^n;{\mathbb C})\to C^\infty ({\mathbb R}^n; {\mathbb
C})$. This is an entire analytic mapping and we write $ Bv = \sum_1^\infty B_Nv
$ where $B_Nv$ is the $N$:th order term in the power series expansion at $v=0$.
In this paper we study estimates for $B_Nv$ in $H_{(s)}$ spaces, and prove that
$Bv$ is entire analytic in $v \in H_{(s)}\cap \Cal E'$ when $s\ge (n-3)/2$.


title: Resonant tunneling of Bose-Einstein condensates in optical lattices

abstract:
  In this article, we present theoretical as well as experimental results on
resonantly enhanced tunneling of Bose-Einstein condensates in optical lattices
both in the linear case and for small nonlinearities. Our results demonstrate
the usefulness of condensates in optical lattices for simulating Hamiltonians
originally used for describing solid state phenomena.


title: A Separation between Divergence and Holevo Information for Ensembles

abstract:
  The notion of divergence information of an ensemble of probability
distributions was introduced by Jain, Radhakrishnan, and Sen in the context of
the ``substate theorem''. Since then, divergence has been recognized as a more
natural measure of information in several situations in quantum and classical
communication. We construct ensembles of probability distributions for which
divergence information may be significantly smaller than the more standard
Holevo information. As a result, we establish that lower bounds previously
shown for Holevo information are weaker than similar ones shown for divergence
information.


title: Correlation Inequalities for Spin Glass in one Dimension

abstract:
  We prove two inequalities for the direct and truncated correlation for the
nearest-neighboor one-dimensional Edwards-Anderson model with symmetric
quenched disorder. The second inequality has the opposite sign of the GKS
inequality of type II. In the non symmetric case with positive average we show
that while the direct correlation keeps its sign the truncated one changes sign
when crossing a suitable line in the parameter space. That line separates the
regions satisfying the GKS second inequality and the one proved here.

categories: math-ph cond-mat.dis-nn cond-mat.stat-mech math.MP


title:
Jordan-Holder theorem for imprimitivity systems and maximal
  decompositions of rational functions

abstract:
  In this paper we prove several results about the lattice of imprimitivity
systems of a permutation group containing a cyclic subgroup with at most two
orbits. As an application we generalize the first Ritt theorem about functional
decompositions of polynomials, and some other related results. Besides, we
discuss examples of rational functions, related to finite subgroups of the
automorphism group of the sphere for which the first Ritt theorem fails to be
true.


title: Substitute Valuations: Generation and Structure

abstract:
  Substitute valuations (in some contexts called gross substitute valuations)
are prominent in combinatorial auction theory. An algorithm is given in this
paper for generating a substitute valuation through Monte Carlo simulation. In
addition, the geometry of the set of all substitute valuations for a fixed
number of goods K is investigated. The set consists of a union of polyhedrons,
and the maximal polyhedrons are identified for K=4. It is shown that the
maximum dimension of the maximal polyhedrons increases with K nearly as fast as
two to the power K. Consequently, under broad conditions, if a combinatorial
algorithm can present an arbitrary substitute valuation given a list of input
numbers, the list must grow nearly as fast as two to the power K.


title: Multiflavor Soldering

abstract:
  In two dimensions the simple addition of two chiral bosons of opposite
chiralities does not lead to a full massless scalar field. Similarly, in three
dimensions the addition of two Maxwell-Chern-Simons fields of opposite
helicities $\pm 1$ will not produce a parity invariant Maxwell-Proca theory. An
interference term between the opposite chiralities (helicities) states is
required in order to obtain the expected result. The so called soldering
procedure provides the missing interference Lagrangian in both 2D and 3D cases.
In two dimensions such interference term allows to fuse two chiral fermionic
determinants into a nonchiral one. In a recent work we have generalized this
procedure by allowing the appearance of an extra parameter which takes two
possible values and leads to two different soldered Lagrangians. Here we apply
this generalized soldering in a bosonic theory which has appeared in a partial
bosonization of the 3D gauged Thirring with $N$ flavors. The multiplicity of
flavors allow new types of solderings and help us to understand the connection
between different perturbative approaches to bosonization in 3D. In particular,
we obtain an interference term which takes us from a multiflavor
Maxwell-Chern-Simons theory to a pair of self-dual and anti-self-dual theories
when we combine together both fermionic determinants of +1/2 and -1/2 helicity
fermions. An important role is played by a set of pure non-interacting
Chern-Simons fields which amount to a normalization factor in the fermionic
determinants and act like spectators in the original theory but play an active
role in the soldering procedure. Our results suggest that the generalized
soldering could be used to provide dual theories in both 2D and 3D cases.


title:
Restrictions over two-dimensional gauge models with Thirring-like
  interaction

abstract:
  Some years ago, it was shown how fermion self-interacting terms of the
Thirring-type impact the usual structure of massless two-dimensional gauge
theories [1]. In that work only the cases of pure vector and pure chiral gauge
couplings have been considered and the corresponding Thirring term was also
pure vector and pure chiral respectively, such that the vector (or chiral)
Schwinger model should not lose its chirality structure due to the addition of
the quartic interaction term. Here we extend this analysis to a generalized
vector and axial coupling both for the gauge interaction and the quartic
fermionic interactions. The idea is to perform quantization without losing the
original structure of the gauge coupling. In order to do that we make use of an
arbitrariness in the definition of the Thirring-like interaction.


title: On the uniqueness of elliptic K3 surfaces with maximal singular fibre

abstract:
  We explicitly determine the elliptic K3 surfaces with a maximal singular
fibre. If the characteristic of the ground field is different from 2, for each
of the two possible maximal fibre types, $I_{19}$ and $I^*_{14}$, the surface
is unique. In characteristic 2 the maximal fibre types are $I_{18}$ and
$I^*_{13}$, and there exist two (resp. one) one-parameter families of such
surfaces.


title:
Deviations from the Flux-Recurrence Time Relationship in GS 1826-238:
  Potential Transient Spectral Changes

abstract:
  The low-mass X-ray binary GS 1826-238 is presently unique for its
consistently regular bursting behavior. In previous Rossi X-Ray Timing Explorer
(RXTE) measurements between 1997 November and 2002 July, this source exhibited
(nearly) limit-cycle bursts with recurrence times that decreased
proportionately as the persistent flux increased. Here we report additional
measurements of the burst recurrence time by RXTE, Chandra, and XMM-Newton, as
well as observations of optical bursts. On a few occasions we measured burst
recurrence times which deviated significantly from the earlier flux-recurrence
time relationship, and most of these bursts occurred earlier than would be
predicted based on the X-ray flux level. The epochs with early bursts were also
accompanied by unusual broadband timing signatures, with the entire power
spectrum shifting to higher frequencies. Concurrent XMM-Newton observations
during one of these occasions, in 2003 April, indicate that an additional soft
component may be present in the spectrum containing enough flux (30% of the
total) to account for the burst recurrence time discrepancy. A self-consistent
interpretation for the increase in soft flux and accompanying timing changes
during 2003 April is that accretion disk extends down to smaller radial
distances from the source than during the other observing epochs. The RXTE
observations since 2003 April show that the spectral and timing properties have
nearly returned to the previously established level.


title: A Unified Approach to Local Cohomology Modules Using Serre Classes

abstract:
  This paper discusses the connection between the local cohomology modules and
the Serre classes of $R$-modules. Such connection provided a common language
for expressing some results about the local cohomology $R$-modules, that has
appeared in different papers.


title: Explicit Non-Adaptive Combinatorial Group Testing Schemes

abstract:
  Group testing is a long studied problem in combinatorics: A small set of $r$
ill people should be identified out of the whole ($n$ people) by using only
queries (tests) of the form "Does set X contain an ill human?". In this paper
we provide an explicit construction of a testing scheme which is better
(smaller) than any known explicit construction. This scheme has $\bigT{\min[r^2
\ln n,n]}$ tests which is as many as the best non-explicit schemes have. In our
construction we use a fact that may have a value by its own right: Linear
error-correction codes with parameters $[m,k,\delta m]_q$ meeting the
Gilbert-Varshamov bound may be constructed quite efficiently, in $\bigT{q^km}$
time.


title: The Dehn function of Stallings' group

abstract:
  We prove that the Dehn function of a group of Stallings that is finitely
presented but not of type F_3 is quadratic. To appear in Geometric and
Functional Analysis.


title: Trisecant Lemma for Non Equidimensional Varieties

abstract:
  The classic trisecant lemma states that if $X$ is an integral curve of
$\PP^3$ then the variety of trisecants has dimension one, unless the curve is
planar and has degree at least 3, in which case the variety of trisecants has
dimension 2. In this paper, our purpose is first to present another derivation
of this result and then to introduce a generalization to non-equidimensional
varities. For the sake of clarity, we shall reformulate our first problem as
follows. Let $Z$ be an equidimensional variety (maybe singular and/or
reducible) of dimension $n$, other than a linear space, embedded into $\PP^r$,
$r \geq n+1$. The variety of trisecant lines of $Z$, say $V_{1,3}(Z)$, has
dimension strictly less than $2n$, unless $Z$ is included in a
$(n+1)-$dimensional linear space and has degree at least 3, in which case
$\dim(V_{1,3}(Z)) = 2n$. Then we inquire the more general case, where $Z$ is
not required to be equidimensional. In that case, let $Z$ be a possibly
singular variety of dimension $n$, that may be neither irreducible nor
equidimensional, embedded into $\PP^r$, where $r \geq n+1$, and $Y$ a proper
subvariety of dimension $k \geq 1$. Consider now $S$ being a component of
maximal dimension of the closure of $\{l \in \G(1,r) \vtl \exists p \in Y, q_1,
q_2 \in Z \backslash Y, q_1,q_2,p \in l\}$. We show that $S$ has dimension
strictly less than $n+k$, unless the union of lines in $S$ has dimension $n+1$,
in which case $dim(S) = n+k$. In the latter case, if the dimension of the space
is stricly greater then $n+1$, the union of lines in $S$ cannot cover the whole
space. This is the main result of our work. We also introduce some examples
showing than our bound is strict.


title: Observation of Anomalous Phonon Softening in Bilayer Graphene

abstract:
  The interaction of electron-hole pairs with lattice vibrations exhibits a
wealth of intriguing physical phenomena. The Kohn anomaly is a renowned example
where electron-phonon coupling leads to non-analytic phonon dispersion at
specific momentum nesting the Fermi surface. Here we report evidence of another
type of phonon anomaly discovered by low temperature Raman spectroscopy in
bilayer graphene where the charge density is modulated by the electric field
effect. This anomaly, arising from charge-tunable modulations of particle-hole
pairs that are resonantly coupled to lattice vibrations, is predicted to
exhibit a logarithmic divergence in the long-wavelength optical-phonon energy.
In a non-uniform bilayer of graphene, the logarithmic divergence is abated by
charge density inhomogeneity leaving as a vestige an anomalous phonon
softening. The observed softening marks the first confirmation of the phonon
anomaly as a key signature of the resonant deformation-potential
electron-phonon coupling. The high sensitivity of the phonon softening to
charge density non-uniformity creates significant venues to explore the
interplay between fundamental interactions and disorder in the atomic layers.


title:
A Raman study of the Charge-Density-Wave State in A$_{0.3}$MoO$_3$ (A =
  K,Rb)

abstract:
  We report a comparative Raman spectroscopic study of the
quasi-one-dimensional charge-density-wave systems \ab (A = K, Rb). The
temperature and polarization dependent experiments reveal charge-coupled
vibrational Raman features. The strongly temperature-dependent collective
amplitudon mode in both materials differ by about 3 cm, thus revealing the role
of alkali atom. We discus the observed vibrational features in terms of
charge-density-wave ground state accompanied by change in the crystal symmetry.
A frequency-kink in some modes seen in \bb between T = 80 K and 100 K supports
the first-order lock-in transition, unlike \rb. The unusually sharp Raman
lines(limited by the instrumental response) at very low temperatures and their
temperature evolution suggests that the decay of the low energy phonons is
strongly influenced by the presence of the temperature dependent charge density
wave gap.


title: Further results on the Craig-Sakamoto equation

abstract:
  In this paper necessary and sufficient conditions are stated for the
Craig-Sakamoto equation det(I-sA-tB) = det(I-sA)det(I-tB), for all scalars s,
t. Moreover, spectral properties for A and B are investigated.


title: Arithmetic progressions in sets of fractional dimension

abstract:
  Let $E\subset\rr$ be a closed set of Hausdorff dimension $\alpha$. We prove
that if $\alpha$ is sufficiently close to 1, and if $E$ supports a
probabilistic measure obeying appropriate dimensionality and Fourier decay
conditions, then $E$ contains non-trivial 3-term arithmetic progressions.


title: The generalized Levinger transformation

abstract:
  In this paper, we present new results relating the numerical range of a
matrix $A$ with generalized Levinger transformation
$\mathcal{L}(A,\alpha,\beta) = \alphaH_A +\betaS_A$, where $H_A$ and $S_A$, are
respectively the Hermitian and skew-hermitian parts of $A$. Using these
results, we derive expressions for eigenvalues and eigenvectors of the
perturbed matrix $A + \mathcal{L}(E,\alpha,\beta)$, for a fixed matrix $E$ and
$\alpha, \beta$ are real parameters.


title: Slow energy dissipation in anharmonic oscillator chains

abstract:
  We study the dynamic behavior at high energies of a chain of anharmonic
oscillators coupled at its ends to heat baths at possibly different
temperatures. In our setup, each oscillator is subject to a homogeneous
anharmonic pinning potential $V_1(q_i) =|q_i|^{2k}/2k$ and harmonic coupling
potentials $V_2(q_i- q_{i-1}) = (q_i- q_{i-1})^2/2$ between itself and its
nearest neighbors. We consider the case $k > 1$ when the pinning potential is
stronger then the coupling potential. At high energy, when a large fraction of
the energy is located in the bulk of the chain, breathers appear and block the
transport of energy through the system, thus slowing its convergence to
equilibrium.
  In such a regime, we obtain equations for an effective dynamics by averaging
out the fast oscillation of the breather. Using this representation and related
ideas, we can prove a number of results. When the chain is of length three and
$k> 3/2$ we show that there exists a unique invariant measure. If $k > 2$ we
further show that the system does not relax exponentially fast to this
equilibrium by demonstrating that zero is in the essential spectrum of the
generator of the dynamics. When the chain has five or more oscillators and $k>
3/2$ we show that the generator again has zero in its essential spectrum.
  In addition to these rigorous results, a theory is given for the rate of
decrease of the energy when it is concentrated in one of the oscillators
without dissipation. Numerical simulations are included which confirm the
theory.


title: Line Shapes of the Z(4430)

abstract:
  The Belle Collaboration recently discovered the first manifestly exotic
meson: Z^+(4430), which decays into psi' pi^+ and therefore has quark content c
c-bar u d-bar. The proximity of its mass to the D_1 D-bar^* threshold has
motivated the interpretation of the Z^+ as a charm meson molecule whose
constituents are an S-wave superposition of D_1^+ D-bar^{*0}$ and D^{*+}
D-bar_1^0$. If this interpretation is correct, the small ratio of the binding
energy of the Z^+ to the width Gamma_1 of its constituent D_1 can be exploited
to predict properties of its line shapes. Its full width at half maximum in the
channel psi' pi^+ should be approximately sqrt{3} Gamma_1 = 35 MeV, which is
consistent with the measured width of the Z^+. The Z^+ should also decay into
D^* D-bar^* pi through decay of its constituent D_1. The peak in the line shape
for D^* D-bar^* pi should be at a higher energy than the peak in the line shape
for psi' pi^+ by about Gamma_1/sqrt{12} = 6 MeV. The line shape in D^* D-bar^*
pi should also be broader and asymmetric, with a shoulder on the high energy
side that can be attributed to a threshold enhancement in the production of D_1
D-bar^*.


title: Calculation of UNil for the cyclic group of order two

abstract:
  Cappell's unitary nilpotent groups UNil(R;R,R) are calculated for the
integral group ring R=Z[C_2] of the cyclic group C_2 of order two.
Specifically, they are determined as modules over the Verschiebung algebra V
using the Connolly--Ranicki isomorphism and the Connolly--Davis relations.


title: QuanTree and QuanLin, Two Special Purpose Quantum Compilers

abstract:
  This paper introduces QuanTree v1.1 and QuanLin v1.1, two Java applications
available for free. (Source code included in the distribution.) Each
application compiles a different type of input quantum evolution operator. The
applications output a quantum circuit that is approximately equal to the input
evolution operator. QuanTree compiles an input evolution operator whose
Hamiltonian is proportional to the incidence matrix of a balanced, binary tree
graph. QuanLin compiles an input evolution operator whose Hamiltonian is
proportional to the incidence matrix of a line (open string) graph. Both
applications also output an error, defined as the distance in the Frobenius
norm between the input evolution operator and the output quantum circuit.


title:
Orthogonalization Properties of Linear Deterministic Polarization
  Elements

abstract:
  The conditions under which a linear anisotropic polarization element
orthogonalizes several polarization states of input totally polarized light
were studied in the paper. The criterion for orthogonalization was obtained in
the form of inequality for anisotropy parameters. Orthogonalization properties
of polarization elements with the most important anisotropy types were
investigated. The parameters under which orthogonalization occurs, and the
states that are orthogonalized were found. The loci of these states on the
Poincare sphere were given for sake of illustration in each case.


title: Heteronuclear molecules in an optical dipole trap

abstract:
  We report on the creation and characterization of heteronuclear KRb Feshbach
molecules in an optical dipole trap. Starting from an ultracold gas mixture of
K-40 and Rb-87 atoms, we create as many as 25,000 molecules at 300 nK by rf
association. Optimizing the association process, we achieve a conversion
efficiency of 25%. We measure the temperature dependence of the rf association
process and find good agreement with a phenomenological model that has
previously been applied to Feshbach molecule creation by slow magnetic-field
sweeps. We also present a measurement of the binding energy of the
heteronuclear molecules in the vicinity of the Feshbach resonance and provide
evidence for Feshbach molecules as deeply bound as 26 MHz.


title: Spin-orbit coupling in bulk GaAs

abstract:
  We study the spin-orbit coupling in the whole Brillouin zone for GaAs using
both the $sp^3s^{\ast}d^5$ and $sp^3s^{\ast}$ nearest-neighbor tight-binding
models. In the $\Gamma$-valley, the spin splitting obtained is in good
agreement with experimental data. We then further explicitly present the
coefficients of the spin splitting in GaAs $L$ and $X$ valleys. These results
are important to the realization of spintronic device and the investigation of
spin dynamics far away from equilibrium.


title:
The Dynamics of Relativistic Length Contraction and the Ehrenfest
  Paradox

abstract:
  Relativistic kinematics is usually considered only as a manifestation of
pseudo-Euclidean (Lorentzian) geometry of space-time. However, as it is
explicitly stated in General Relativity, the geometry itself depends on
dynamics, specifically, on the energy-momentum tensor. We discuss a few
examples, which illustrate the dynamical aspect of the length-contraction
effect within the framework of Special Relativity. We show some pitfalls
associated with direct application of the length contraction formula in cases
when an extended object is accelerated. Our analysis reveals intimate
connections between length contraction and the dynamics of internal forces
within the accelerated system.
  The developed approach is used to analyze the correlation between two
congruent disks - one stationary and one rotating (the Ehrenfest paradox).
Specifically, we consider the transition of a disk from the state of rest to a
spinning state under the applied forces. It reveals the underlying physical
mechanism in the corresponding transition from Euclidean geometry of stationary
disk to Lobachevsky's (hyperbolic) geometry of the spinning disk in the process
of its rotational boost. A conclusion is made that the rest mass of a spinning
disk or ring of a fixed radius must contain an additional term representing the
potential energy of non-Euclidean circumferential deformation of its material.
Possible experimentally observable manifestations of Lobachevsky's geometry of
rotating systems are discussed.


title:
Determinantal identity for multilevel systems and finite determinantal
  processes

abstract:
  We give a simple algebraic derivation of a useful determinantal identity for
multilevel systems such as random matrix chains and finite determinantal point
processes, with applications to the calculation of point correlators, gap
probabililties and Janossy densities.

categories: math-ph cond-mat.stat-mech hep-th math.MP math.PR


title: KATRIN: an experiment to measure the neutrino mass

abstract:
  KATRIN is a very large scale tritium-beta-decay experiment to determine the
mass of the neutrino. It is presently under construction at the
Forschungszentrum Karlsruhe, and makes use of the Tritium Laboratory built
there for the ITER project. The combination of a very large retarding-potential
electrostatic-magnetic spectrometer and an intense gaseous molecular tritium
source makes possible a sensitivity to neutrino mass of 0.2 eV, about an order
of magnitude below present laboratory limits. The measurement is kinematic and
independent of whether the neutrino is Dirac or Majorana. The status of the
project is summarized briefly in this report.


title:
Ultra-discretization of the G^(1)_2-Geometric Crystals to the
  D^(3)_4-Perfect Crystals

abstract:
  We obtain the affirmative answer to the conjecture in [15]. More precisely,
let X be the affine geometric crystal of type G^(1)_2 in [15] and
UD(X,T,\theta) a ultra-discretization of X with respect to a certain positive
structure \theta. Then we show that UD(X,T,\theta) is isomorphic to the limit
of coherent family of perfect crystals of type D^(3)_4 in [7].


title: An Enumeration of Graphical Designs

abstract:
  Let $\Psi(t,k)$ denote the set of pairs $(v,\lambda)$ for which there exists
a graphical $t$-$(v,k,\lambda)$ design. Most results on graphical designs have
gone to show the finiteness of $\Psi(t,k)$ when $t$ and $k$ satisfy certain
conditions. The exact determination of $\Psi(t,k)$ for specified $t$ and $k$ is
a hard problem and only $\Psi(2,3)$, $\Psi(2,4)$, $\Psi(3,4)$, $\Psi(4,5)$, and
$\Psi(5,6)$ have been determined. In this paper, we determine completely the
sets $\Psi(2,5)$ and $\Psi(3,5)$. As a result, we find more than 270000
inequivalent graphical designs, and more than 8000 new parameter sets for which
there exists a graphical design. Prior to this, graphical designs are known for
only 574 parameter sets.


title: Tighter and Stable Bounds for Marcum Q-Function

abstract:
  This paper proposes new bounds for Marcum Q-function, which prove extremely
tight and outperform all the bounds previously proposed in the literature. What
is more, the proposed bounds are good and stable both for large values and
small values of the parameters of the Marcum Q-function, where the previously
introduced bounds are bad and even useless under some conditions. The new
bounds are derived by refined approximations for the 0th order modified Bessel
function in the integration region of the Marcum Q-function. They should be
useful since they are always tight no matter the parameters are large or small.


title: Topological Maps from Signals

abstract:
  We discuss the task of reconstructing the topological map of an environment
based on the sequences of locations visited by a mobile agent -- this occurs in
systems neuroscience, where one runs into the task of reconstructing the global
topological map of the environment based on activation patterns of the place
coding cells in hippocampus area of the brain. A similar task appears in the
context of establishing wifi connectivity maps.


title:
Effective Photon Hypothesis, Self Focusing of Laser Beams and Super
  Fluid

abstract:
  The effective photon hypothesis of Panarella and Raychaudhuri shows that the
self focusing of photon in the laser beam is inherent and it also shows that
the the cause of phenomena of self focusing of intense laser radiation in
solids is not actually the nonlinear intensity dependent refractive index. In
the effective photon hypothesis the laser photon have much better chance than
ordinary photon to undergo a phase transition to a superfluid state.
  If a super fluid photon in the laser beam can be realized then in the
effective photon hypothesis gives interesting results. The effective photon
hypothesis shows that if the average energy X-ray laser beams is $h\nu=10^{3}$
$eV \sim 10^{4}$ $eV$, we find that mass of the quasiparticles in the X-ray
laser beams is in the range $10^{5}$ $eV \sim 10^{12}$ $eV$. Thus the mass of
the quasipartcle in the X-ray laser beams can be $Z$-boson of the electroweak
theory of weak interactions. It is possible that $W^{+}$ and $W^{-}$ can be
originated from another vector boson whose mass is more than 200 GeV.


title:
Annular interdigital transducer focuses piezoelectric surface waves to a
  single point

abstract:
  We propose and demonstrate experimentally the concept of the annular
interdigital transducer that focuses acoustic waves on the surface of a
piezoelectric material to a single, diffraction-limited, spot. The shape of the
transducing fingers follows the wave surface. Experiments conducted on lithium
niobate substrates evidence that the generated surface waves converge to the
center of the transducer, producing a spot that shows a large concentration of
acoustic energy. This concept is of practical significance to design new
intense microacoustic sources, for instance for enhanced acouto-optical
interactions.


title:
Integrating heterogeneous knowledges for understanding biological
  behaviors: a probabilistic approach

abstract:
  Despite recent molecular technique improvements, biological knowledge remains
incomplete. Reasoning on living systems hence implies to integrate
heterogeneous and partial informations. Although current investigations
successfully focus on qualitative behaviors of macromolecular networks, others
approaches show partial quantitative informations like protein concentration
variations over times. We consider that both informations, qualitative and
quantitative, have to be combined into a modeling method to provide a better
understanding of the biological system. We propose here such a method using a
probabilistic-like approach. After its exhaustive description, we illustrate
its advantages by modeling the carbon starvation response in Escherichia coli.
In this purpose, we build an original qualitative model based on available
observations. After the formal verification of its qualitative properties, the
probabilistic model shows quantitative results corresponding to biological
expectations which confirm the interest of our probabilistic approach.


title:
The dipole form of the BFKL kernel in supersymmetric Yang--Mills
  theories

abstract:
  The dipole (M\"{o}bius) representation of the colour singlet BFKL kernel in
the next-to-leading order is found in supersymmetric Yang--Mills theories.
Ambiguities of this form and its conformal properties are discussed.


title: Addition Theorems Via Continued Fractions

abstract:
  We show connections between a special type of addition formulas and a theorem
of Stieltjes and Rogers. We use different techniques to derive the desirable
addition formulas. We apply our approach to derive special addition theorems
for Bessel functions and confluent hypergeometric functions. We also derive
several additions theorems for basic hypergeometric functions. Applications to
the evaluation of Hankel determinants are also given .


title:
Helical ${\alpha}$-dynamos as twisted magnetic flux tubes in Riemannian
  space

abstract:
  Analytical solution of ${\alpha}$-dynamo equation representing strongly
torsioned helical dynamo is obtained in the thin twisted Riemannian flux tubes
approximation. The $\alpha$ factor possesses a fundamental contribution from
torsion which is however weaken in the thin tubes approximation. It is shown
that assuming that the poloidal component of the magnetic field is in principle
time-independent, the toroidal magnetic field component grows very fast in
time, actually it possesses a linear time dependence, while the poloidal
component grows under the influence of torsion or twist of the flux tube. The
toroidal component decays spatially with as $r^{-2}$ while vorticity may decay
as $r^{-5}$ (poloidal component) where r represents the radial distance from
the magnetic axis of flux tube. Toroidal component of vorticity decays as
$r^{-1}$. In turbulent dynamos unbounded magnetic fields may decay at least as
$r^{-3}$.


title: Comment on "Feasibility of an electron-based crystalline undulator"

abstract:
  Tabrizi et al. [physics/0701342] discuss the feasibility of an electron-based
crystal undulator (e-CU) by planar channeling of 50 GeV electrons through a
periodically bent crystal. We show that their scheme is not feasible. First,
their undulator parameter is K >> 1 always, which destroys photon interference.
Second, they overestimate the electron dechanneling length in e-CU by an order
of magnitude, which shortens the number N of e-CU periods from 5-15 (as they
hope) to just 1-2. This kills their e-CU concept again. We made first
simulation of electron channeling in undulated crystal and conclude that an
electron-based crystal wiggler is feasible with wiggler strength K=10 and
number of periods N=2.


title: Moser-Trudinger and Beckner-Onofri's inequalities on the CR sphere

abstract:
  We derive sharp Moser-Trudinger inequalities on the CR sphere. The first type
is in the Adams form, for powers of the sublaplacian and for general spectrally
defined operators on the space of CR-pluriharmonic functions. We will then
obtain the sharp Beckner-Onofri inequality for CR-pluriharmonic functions on
the sphere, and, as a consequence, a sharp logarithmic Hardy-Littlewood-Sobolev
inequality in the form given by Carlen and Loss.


title: Optimization in task--completion networks

abstract:
  We discuss the collective behavior of a network of individuals that receive,
process and forward to each other tasks. Given costs they store those tasks in
buffers, choosing optimally the frequency at which to check and process the
buffer. The individual optimizing strategy of each node determines the
aggregate behavior of the network. We find that, under general assumptions, the
whole system exhibits coexistence of equilibria and hysteresis.


title: Highly distorted apparent horizons and the hoop conjecture

abstract:
  By analyzing the apparent horizon (AH) formation in the collision of two
pp-waves with rectangular sources in four dimensions, we study to what extent
the AH can be distorted without violating the energy conditions. It is shown
that the highly distorted AH can form in this system although it cannot be
arbitrarily long. The hoop conjecture is examined for the formation of such
highly distorted AHs, and our result gives a strong support to the hoop
conjecture. We also point out the possible relation between the AH topology
theorem and the hoop conjecture.


title: Stochastic integration based on simple, symmetric random walks

abstract:
  A new approach to stochastic integration is described, which is based on an
a.s. pathwise approximation of the integrator by simple, symmetric random
walks. Hopefully, this method is didactically more advantageous, more
transparent, and technically less demanding than other existing ones. In a
large part of the theory one has a.s. uniform convergence on compacts. In
particular, it gives a.s. convergence for the stochastic integral of a finite
variation function of the integrator, which is not c\`adl\`ag in general.


title: Lusztig's conjecture as a moment graph problem

abstract:
  We show that Lusztig's conjecture on the irreducible characters of a
reductive algebraic group over a field of positive characteristic is equivalent
to the generic multiplicity conjecture, which gives a formula for the
Jordan-H"older multiplicities of baby Verma modules over the corresponding Lie
algebra. Then we give a short overview of a recent proof of the latter
conjecture for almost all base fields via the theory of sheaves on moment
graphs.


title: Faster than Hermitian Time Evolution

abstract:
  For any pair of quantum states, an initial state |I> and a final quantum
state |F>, in a Hilbert space, there are many Hamiltonians H under which |I>
evolves into |F>. Let us impose the constraint that the difference between the
largest and smallest eigenvalues of H, E_max and E_min, is held fixed. We can
then determine the Hamiltonian H that satisfies this constraint and achieves
the transformation from the initial state to the final state in the least
possible time \tau. For Hermitian Hamiltonians, \tau has a nonzero lower bound.
However, among non-Hermitian PT-symmetric Hamiltonians satisfying the same
energy constraint, \tau can be made arbitrarily small without violating the
time-energy uncertainty principle. The minimum value of \tau can be made
arbitrarily small because for PT-symmetric Hamiltonians the path from the
vector |I> to the vector |F>, as measured using the Hilbert-space metric
appropriate for this theory, can be made arbitrarily short. The mechanism
described here is similar to that in general relativity in which the distance
between two space-time points can be made small if they are connected by a
wormhole. This result may have applications in quantum computing.


title:
N-systems, class polynomials for double eta-quotients and singular
  values of J-invariant function

abstract:
  Enge and Schertz gave the method of using the double eta-quotient for the
construction of elliptic curves over finite fields. In their method, it is
necessary to count the number of rational points of elliptic curves
corresponding to solutions of the modular equation over a finite field, because
in advance we can not know which solution of the modular equation is that
corresponding to the modular invariant. We give a condition that the modular
invariant is a multiple root of the modular polynomial. Consequently, we give a
method to reduce the amount of computation in the process of counting the
number of rational points.


title: Direct determination of neutrino mass parameters at future colliders

abstract:
  If the observed light neutrino masses are induced by their Yukawa couplings
to singlet right-handed neutrinos, natural smallness of those renders direct
collider tests of the electroweak scale neutrino mass mechanisms almost
impossible both in the case of Dirac and Majorana (seesaw of type I) neutrinos.
However, in the triplet Higgs seesaw scenario the smallness of light neutrino
masses may come from the smallness of B-L breaking parameters, allowing sizable
Yukawa couplings even for a TeV scale triplet. We show that, in this scenario,
measuring the branching fractions of doubly charged Higgs to different
same-charged lepton flavours at LHC and/or ILC experiments will allow one to
measure the neutrino mass parameters which neutrino oscillation experiments are
insensitive to, including the neutrino mass hierarchy, lightest neutrino mass
and Majorana phases.


title:
Initial-state showering based on colour dipoles connected to incoming
  parton lines

abstract:
  A parton-shower model for hadronic collisions based on the emission
properties of QCD dipoles is proposed. This proposal therefore extends the
well-known radiation pattern of pure final-state colour dipoles to QCD
initial-state radiation, both of which are treated perturbatively.
Corresponding dipole splitting functions are derived and the kinematics of all
dipole splittings is discussed. Application to hadron production in
electron-positron annihilation, to Drell-Yan lepton-pair and QCD jet production
yields encouraging results.


title: Phase diagram of the one dimensional anisotropic Kondo-necklace model

abstract:
  The one dimensional anisotropic Kondo-necklace model has been studied by
several methods. It is shown that a mean field approach fails to gain the
correct phase diagram for the Ising type anisotropy. We then applied the spin
wave theory which is justified for the anisotropic case. We have derived the
phase diagram between the antiferromagnetic long range order and the Kondo
singlet phases. We have found that the exchange interaction (J) between the
itinerant spins and local ones enhances the quantum fluctuations around the
classical long range antiferromagnetic order and finally destroy the ordered
phase at the critical value, J_c. Moreover, our results show that the onset of
anisotropy in the XY term of the itinerant interactions develops the
antiferromagnetic order for J<J_c. This is in agreement with the qualitative
feature which we expect from the symmetry of the anisotropic XY interaction. We
have justified our results by the numerical Lanczos method where the structure
factor at the antiferromagnetic wave vector diverges as the size of system goes
to infinity.


title: No Zero Divisor for Wick Product in $(S)^{\ast}$}

abstract:
  In White Noise Analysis (WNA), various random quantities are analyzed as
elements of $(S)^{\ast}$, the space of Hida distributions ([1]). Hida
distributions are generalized functions of white noise, which is to be
naturally viewed as the derivative of the Brownian motion. On $(S)^{\ast}$, the
Wick product is defined in terms of the $\mathcal{S}$-transform. We have found
such a remarkable property that the Wick product has no zero devisors among
Hida distributions. This result is a WNA version of Titchmarsh's theorem and is
expected to play fundamental roles in developing the \textquotedblleft
operational calculus\textquotedblright in WNA along the line of
Mikusi\'{n}ski's version for solving differential equations.


title: Discrete logarithms in curves over finite fields

abstract:
  A survey on algorithms for computing discrete logarithms in Jacobians of
curves over finite fields.


title: Five Planets Orbiting 55 Cancri

abstract:
  We report 18 years of Doppler shift measurements of a nearby star, 55 Cancri,
that exhibit strong evidence for five orbiting planets. The four previously
reported planets are strongly confirmed here. A fifth planet is presented, with
an apparent orbital period of 260 days, placing it 0.78 AU from the star in the
large empty zone between two other planets. The velocity wobble amplitude of
4.9 \ms implies a minimum planet mass \msini = 45.7 \mearthe. The orbital
eccentricity is consistent with a circular orbit, but modest eccentricity
solutions give similar \chisq fits. All five planets reside in low eccentricity
orbits, four having eccentricities under 0.1. The outermost planet orbits 5.8
AU from the star and has a minimum mass, \msini = 3.8 \mjupe, making it more
massive than the inner four planets combined. Its orbital distance is the
largest for an exoplanet with a well defined orbit. The innermost planet has a
semi-major axis of only 0.038 AU and has a minimum mass, \msinie, of only 10.8
\mearthe, one of the lowest mass exoplanets known. The five known planets
within 6 AU define a {\em minimum mass protoplanetary nebula} to compare with
the classical minimum mass solar nebula. Numerical N-body simulations show this
system of five planets to be dynamically stable and show that the planets with
periods of 14.65 and 44.3 d are not in a mean-motion resonance. Millimagnitude
photometry during 11 years reveals no brightness variations at any of the
radial velocity periods, providing support for their interpretation as
planetary.


title: Digital Image Mechanical Identification (DIMI)

abstract:
  A continuous pathway from digital images acquired during a mechanical test to
quantitative identification of a constitutive law is presented herein based on
displacement field analysis. From images, displacement fields are directly
estimated within a finite element framework. From the latter, the application
of the equilibrium gap method provides the means for rigidity field evaluation.
In the present case, a reconditioned formulation is proposed for a better
stability. Last, postulating a specific form of a damage law, a linear system
is formed that gives a direct access to the (non-linear) damage growth law in
one step. The two last procedures are presented, validated on an artificial
case, and applied to the case of a biaxial tension of a composite sample driven
up to failure. A quantitative estimate of the quality of the determination is
proposed, and in the last application, it is shown that no more than 7% of the
displacement field fluctuations are not accounted for by the determined damage
law.


title: The Delta(1232) Resonance in Chiral Effective Field Theory

abstract:
  I discuss the problem of formulating the baryon chiral perturbation theory
($\chi$PT) in the presence of a light resonance, such as the $\Delta(1232)$,
the lightest nucleon resonance. It is shown how to extend the power counting of
$\chi$PT to correctly account for the resonant contributions. Recent
applications of the resulting chiral effective-field theory to the description
of pion production reactions in $\Delta$-resonance region are briefly reviewed.


title: Asymptotic Models for Internal Waves

abstract:
  We derived here in a systematic way, and for a large class of scaling
regimes, asymptotic models for the propagation of internal waves at the
interface between two layers of immiscible fluids of different densities, under
the rigid lid assumption and with a flat bottom. The full (Euler) model for
this situation is reduced to a system of evolution equations posed spatially on
$\R^d$, $d=1,2$, which involve two nonlocal operators. The different asymptotic
models are obtained by expanding the nonlocal operators with respect to
suitable small parameters that depend variously on the amplitude, wave-lengths
and depth ratio of the two layers. We rigorously derive classical models and
also some model systems that appear to be new. Furthermore, the consistency of
these asymptotic systems with the full Euler equations is established.


title:
A study of localisation in dual-phase high-strength steels under dynamic
  loading using digital image correlation and FE analysis

abstract:
  Tensile tests were conducted on dual-phase high-strength steel in a
Split-Hopkinson Tension Bar at a strain-rate in the range of 150-600/s and in a
servo-hydraulic testing machine at a strain-rate between 10-3 and 100/s. A
novel specimen design was utilized for the Hopkinson bar tests of this sheet
material. Digital image correlation was used together with high-speed
photography to study strain localisation in the tensile specimens at high rates
of strain. By using digital image correlation, it is possible to obtain
in-plane displacement and strain fields during non-uniform deformation of the
gauge section, and accordingly the strains associated with diffuse and
localised necking may be determined. The full-field measurements in high
strain-rate tests reveal that strain localisation started even before the
maximum load was attained in the specimen. An elasto-viscoplastic constitutive
model is used to predict the observed stress-strain behaviour and strain
localisation for the dual-phase steel. Numerical simulations of dynamic tensile
tests were performed using the non-linear explicit FE code LS-DYNA. Simulations
were done with shell (plane stress) and brick elements. Good correlation
between experiments and numerical predictions was achieved, in terms of
engineering stress-strain behaviour, deformed geometry and strain fields.
However, mesh density plays a role in the localisation of deformation in
numerical simulations, particularly for the shell element analysis.


title:
A comparative study of two phenomenological models of dephasing in
  series and parallel resistors

abstract:
  We compare two phenomenological models of dephasing that are in use recently.
We show that the stochastic absorption model leads to reasonable dephasing in
series (double barrier) and parallel (ring) quantum resistors in presence and
absence of magnetic flux. For large enough dephasing it leads to Ohm's law. On
the other hand a random phase based statistical model that uses averaging over
Gaussian random-phases, picked up by the propagators, leads to several
inconsistencies. This can be attributed to the failure of this model to dephase
interference between complementary electron waves each following time-reversed
path of the other.


title: On Unparticles and K+ to pi+ Missing Energy

abstract:
  We analyze the branching ratio and spectrum for the decay mode $K^+
\to\pi^++{\not}E$(missing energy) in the unparticle model, where an unparticle
can also serve as the missing energy. A vector unparticle can even mediate the
$K^+ \to \pi^+ +\nu \bar{\nu}$, resulting complicated interference with the
Standard Model.


title: Descents and nodal load in scale-free networks

abstract:
  The load of a node in a network is the total traffic going through it when
every node pair sustains a uniform bidirectional traffic between them on
shortest paths. We show that nodal load can be expressed in terms of the more
elementary notion of a node's descents in breadth-first-search (BFS or
shortest-path) trees, and study both the descent and nodal-load distributions
in the case of scale-free networks. Our treatment is both semi-analytical
(combining a generating-function formalism with simulation-derived BFS
branching probabilities) and computational for the descent distribution; it is
exclusively computational in the case of the load distribution. Our main result
is that the load distribution, even though it can be disguised as a power-law
through subtle (but inappropriate) binning of the raw data, is in fact a
succession of sharply delineated probability peaks, each of which can be
clearly interpreted as a function of the underlying BFS descents. This find is
in stark contrast with previously held belief, based on which a power law of
exponent -2.2 was conjectured to be valid regardless of the exponent of the
power-law distribution of node degrees.


title: QIS-XML: A metadata specification for Quantum Information Science

abstract:
  While Quantum Information Science (QIS) is still in its infancy, the ability
for quantum based hardware or computers to communicate and integrate with their
classical counterparts will be a major requirement towards their success.
Little attention however has been paid to this aspect of QIS. To manage and
exchange information between systems, today's classic Information Technology
(IT) commonly uses the eXtensible Markup Language (XML) and its related tools.
XML is composed of numerous specifications related to various fields of
expertise. No such global specification however has been defined for quantum
computers. QIS-XML is a proposed XML metadata specification for the description
of fundamental components of QIS (gates & circuits) and a platform for the
development of a hardware independent low level pseudo-code for quantum
algorithms. This paper lays out the general characteristics of the QIS-XML
specification and outlines practical applications through prototype use cases.


title:
Exact relativistic tritium beta-decay endpoint spectrum in a hadron
  model

abstract:
  We present the relativistic calculation of the beta-decay of tritium in a
hadron model. The elementary particle treatment of the transition 3H -> 3He +
e^- + nu_e is performed in analogy with the description of the beta-decay of
neutron. The effects of higher order terms of hadron current and nuclear recoil
are taken into account in this formalism. The relativistic Kurie function is
derived and presented in a simple form suitable for the determination of
neutrino masses from the shape of the endpoint spectrum. A connection with the
commonly used Kurie function is established.


title:
Bidirectional wavelength tuning of semiconductor quantum dots as
  artificial atoms in an optical resonator

abstract:
  We consider a pair of artificial atoms with different ground state energies.
By means of finite element calculations we predict that the ground state
energies can be tuned into resonance if the artificial atoms are placed into a
flexible ring structure, which is elastically deformed by an external force.
This concept is experimentally verified by embedding a low density of
self-assembled quantum dots into the wall of a rolled up micro tube ring
resonator. We demonstrate that quantum dots can elastically be tuned in- and
out of resonance with each other or with the ring resonator modes.


title: Effect of edge roughness in graphene nanoribbon transistors

abstract:
  The effects of edge irregularity and mixed edge shapes on the characteristics
of graphene nanoribbon transistors are examined by self-consistent atomistic
simulations based on the non-equilibrium Green's function formalism. The
minimal leakage current increases due to the localized states induced in the
band gap, and the on-current decreases due to smaller quantum transmission and
the self-consistent electrostatic effect in general. Although the ratio between
the on-current and minimal leakage current decreases, the transistor still
switches even in the presence of edge roughness. The variation between devices,
however, can be large, especially for a short channel length.


title: Epileptic Seizures: Quakes of the brain?

abstract:
  The concept of universality proposes that dynamical systems with the same
power law behaviors are equivalent at large scales. We test this hypothesis on
the Earth's crust and the epileptic brain, and discover that power laws also
govern the distributions of seizure energies and recurrence times. This robust
correspondence is extended over seven statistics, including the direct and
inverse Omori laws. We also verify in an animal seizure model the
earthquake-driven hypothesis that power law statistics co-exist with
characteristic scales, as coupling between constitutive elements increases
towards the synchronization regime. These observations point to the
universality of the dynamics of coupled threshold oscillators for systems even
as diverse as Earth and brain and suggest a general strategy for forecasting
seizures, one of neurosciences' grails.


title:
Aharonov-Bohm ring with a side-coupled atomic cluster: magneto-transport
  and the selective switching effect

abstract:
  We report electronic transmission properties of a tight binding Aharonov-Bohm
ring threaded by a magnetic flux, to one arm of which a finite cluster of atoms
has been attached from one side. we demonstrate that, by suitably choosing the
number of scatterers in each arm of the quantum ring and, by decoupling the
ring from the atomic cluster, the transmission across the ring can be
completely blocked when the flux threading the ring becomes equal to half the
fundamental flux quantum. A transmission resonance then occurs immediately as
the coupling between the ring and the impurity cluster is switched 'on'. It is
shown that the delta-like transmission resonances occur precisely at the
eigenvalues of the side coupled chain of atoms.Thw 'switching' effect can be
observed either for all the eigenvalues of the isolated atomic cluster, or for
a selected set of them, depending on the number of scatterers in the arms of
the ring. The ring-dot coupling can be gradually increased to suppress the
oscillations in the magneto-transmission completely. However, the suppression
can lead either to a complete transparency or no transmission at all,
occasionally accompanied by a reversal of phase at special values of the
magnetic flux.


title: A Computational Study of Vertical Partial Gate Carbon Nanotube FETs

abstract:
  A vertical partial gate carbon nanotube (CNT) field-effect transistor (FET),
which is amenable to the vertical CNT growth process and offers the potential
for a parallel CNT array channel, is simulated using a self-consistent
atomistic approach. We show that the underlap between the gate and the bottom
electrode (required for isolation between electrodes) is advantageous for
transistor operation because it suppresses ambipolar conduction. A vertical
CNTFET with a gate length that covers only 1/6 of the channel length has a much
smaller minimum leakage current than one without underlap, while maintaining
comparable on current. Both n-type and p-type transistor operations with
balanced performance metrics can be achieved on a single partial gate FET by
using proper bias schemes. Even with a gate underlap, it is demonstrated that
increasing the CNT diameter still leads to a simultaneous increase of on
current and minimum leakage current. Along with a partial gate, the simulated
transistor features a significant amount of air between the surface of the
channel CNT and the gate insulator, as is caused by the vertical CNT growth
process. Filing this pore with a high-k insulator is shown to have the
potential to decrease the on current, due to electrostatic phenomena at the
source-channel contact.


title: A note on Stein fillings of contact manifolds

abstract:
  In this note we construct infinitely many distinct simply connected Stein
fillings of a certain infinite family of contact 3--manifolds.


title: Charged Higgs bosons in the Next-to MSSM (NMSSM)

abstract:
  The charged Higgs boson decays $H^\pm\to W^\pm A_1$ and $H^\pm\to W^\pm h_i$
are studied in the framework of the next-to Minimal Supersymmetric Standard
Model (NMSSM). It is found that the decay rate for $H^\pm\to W^\pm A_1$ can
exceed the rates for the $\tau^\pm\nu$ and $tb$ channels both below and above
the top-bottom threshold. The dominance of $H^\pm\to W^\pm A_1$ is most readily
achieved when $A_1$ has a large doublet component and small mass. We also study
the production process $pp\to H^\pm A_1$ at the LHC followed by the decay
$H^\pm\to W^\pm A_1$ which leads to the signature $W^\pm A_1 A_1$. We suggest
that $p p\to H^\pm A_1$ is a promising discovery channel for a light charged
Higgs boson in the NMSSM with small or moderate $\tan\beta$ and dominant decay
mode $H^\pm \to W^\pm A_1$. This $W^\pm A_1 A_1$ signature can also arise from
the Higgsstrahlung process $pp\to W^\pm h_1$ followed by the decay $h_1\to A_1
A_1$. It is shown that there exist regions of parameter space where these
processes can have comparable cross sections and we suggest that their
respective signals can be distinguished at the LHC by using appropriate
reconstruction methods.


title:
A critical analysis of the GP-B mission. I: on the impossibility of a
  reliable measurement of the gravitomagnetic precession of the GP-B gyroscopes

abstract:
  This submission has been removed because 'G. Forst' is an apparent pseudonym,
in violation of arXiv policies.


title: AB Method of Irrigation without Water (Closed-loop water cycle)

abstract:
  Author suggests and researches a new revolutionary idea for a closed-loop
irrigation method. He offers to cover a given site by a thin closed film with
controlled heat conductivity and clarity located at an altitude of 50 300 m.
The film is supported at altitude by small additional atmospheric overpressure
and connected to the ground by thin cables. Authors show that this closed dome
allows full control of the weather in a given region (the day is always fine,
the rain is only at night, no strong winds). The dome (having control of the
clarity of film and heat conductivity) converts the cold regions to subtropics,
hot deserts and desolate wildernesses to prosperous regions with a temperate
climate. This is a realistic and cheap method of evaporation economical
irrigation and virtual weather control on Earth at the current time.


title: Lagrangian Relaxation and Partial Cover

abstract:
  Lagrangian relaxation has been used extensively in the design of
approximation algorithms. This paper studies its strengths and limitations when
applied to Partial Cover.


title: Tangential symmetries of Darboux integrable systems

abstract:
  In this paper we analyze the tangential symmetries of Darboux integrable
decomposable exterior differential systems. The decomposable systems generalize
the notion of a hyperbolic exterior differential system and include the classic
notion of Darboux integrability for first order systems and second order scalar
equations. For Darboux integrable systems the general solution can be found by
integration (solving ordinary differential equations). We show that this
property holds for our generalized systems as well.
  We give a geometric construction of the Lie algebras of tangential symmetries
associated to the Darboux integrable systems. This construction has the
advantage over previous constructions that our construction does not require
the use of adapted coordinates and works for arbitrary dimension of the
underlying manifold. In particular it works for the prolongations of
decomposable exterior differential systems.


title:
The cosmological constant in the brane world of string theory on
  $S^{1}/Z_{2}$

abstract:
  Orbifold branes in string theory are investigated, and the general field
equations on the branes are given explicitly for type II and heterotic string.
It is shown that the effective cosmological constant on each of the two branes
can be easily lowered to its current observational value, using large extra
dimensions. This is also true for type I string. The radion stability is
studied by using the Goldberger-Wise mechanism, and shown explicitly that it is
stable. Therefore, brane world of string theory provides a viable and built-in
mechanism for solving the long-standing cosmological constant problem. Applying
the formulas to cosmology, we obtain the generalized Friedmann equations on
each of the two branes.


title: Stable, Accelerating Universes in Modified Gravity

abstract:
  Modifications to gravity that add additional functions of the Ricci curvature
to the Einstein-Hilbert action -- collectively known as $f(R)$ theories -- have
been studied in great detail. When considered as complete theories of gravity
they can generate non-perturbative deviations from the general relativistic
predictions in the solar system, and the simplest models show instabilites on
cosmological scales. Here we show that it is possible to treat
$f(R)=R\pm\mu^4/R$ gravity in a perturbative fashion such that it shows no
instabilities on cosmological scales and, in the solar system, is consistent
with measurements of the PPN parameters. We show that such a theory produces a
spatially flat, accelerating universe, even in the absence of dark energy and
when the matter density is too small to close the universe in the general
relativistic case.


title: Short Pulses Approximations in Dispersive Media

abstract:
  We derive various approximations for the solutions of nonlinear hyperbolic
systems with fastly oscillating initial data. We first provide error estimates
for the so-called slowly varying envelope, full dispersion, and Schr\"odinger
approximations in a Wiener algebra; this functional framework allows us to give
precise conditions on the validity of these models; we give in particular a
rigorous proof of the ``practical rule'' which serves as a criterion for the
use of the slowly varying envelope approximation (SVEA). We also discuss the
extension of these models to short pulses and more generally to large spectrum
waves, such as chirped pulses. We then derive and justify rigorously a modified
Schr\"odinger equation with improved frequency dispersion. Numerical
computations are then presented, which confirm the theoretical predictions.


title:
Self-Regulation of Solar Coronal Heating Process via Collisionless
  Reconnection Condition

abstract:
  I propose a new paradigm for solar coronal heating viewed as a
self-regulating process keeping the plasma marginally collisionless. The
mechanism is based on the coupling between two effects. First, coronal density
controls the plasma collisionality and hence the transition between the slow
collisional Sweet-Parker and the fast collisionless reconnection regimes. In
turn, coronal energy release leads to chromospheric evaporation, increasing the
density and thus inhibiting subsequent reconnection of the newly-reconnected
loops. As a result, statistically, the density fluctuates around some critical
level, comparable to that observed in the corona. In the long run, coronal
heating can be represented by repeating cycles of fast reconnection events
(nano-flares), evaporation episodes, and long periods of slow magnetic stress
build-up and radiative cooling of the coronal plasma.


title: Limit curve theorems in Lorentzian geometry

abstract:
  The subject of limit curve theorems in Lorentzian geometry is reviewed. A
general limit curve theorem is formulated which includes the case of converging
curves with endpoints and the case in which the limit points assigned since the
beginning are one, two or at most denumerable. Some applications are
considered. It is proved that in chronological spacetimes, strong causality is
either everywhere verified or everywhere violated on maximizing lightlike
segments with open domain. As a consequence, if in a chronological spacetime
two distinct lightlike lines intersect each other then strong causality holds
at their points. Finally, it is proved that two distinct components of the
chronology violating set have disjoint closures or there is a lightlike line
passing through each point of the intersection of the corresponding boundaries.


title: The chiral transitions in heavy-light mesons

abstract:
  The mass shifts of the $P$-wave $D_s$ and $B_s$ mesons due to coupling to
$DK$, $D^*K$ and $BK$, $B^*K$ channels are studied using the chiral quark-pion
Lagrangian without fitting parameters. The strong mass shifts down $\sim 140$
MeV and $\sim 100$ MeV for $D^*_s(0^+)$ and $D_s(1^{+'})$ and $\sim 100$ MeV
for $B^*_s(0^+)$ and $B_s(1^{+'})$ are calculated. Two factors are essential
for large mass shifts: strong coupling of the $0^+$ and $1^{+'}$ states to the
$S$-wave decay channel, containing a Nambu-Goldstone meson, and the chiral flip
transitions due to the bispinor structure of both heavy-light mesons. The
masses $M(B^*_s(0^+))=5695(10)$ MeV and $M(B_s(1^{+'}))=5730(15)$ MeV,very
close to $M(B(0^+))$ and $M(B(1^{+'}))$, are predicted. Experimental limit on
the width $\Gamma(D_{s1}(2536))<2.3$ MeV puts strong restrictions on admittable
mixing angle between the $1^+$ and $1^{+'}$ states, $|\phi|<6^{\circ}$, which
corresponds to the mixing angle $\theta$ between the $^3P_1$ and $^1P_1$
states, $29^{\circ}<\theta< 41^{\circ}$.


title:
Lagrangian structure functions in fully-developed hydrodynamical
  turbulence

abstract:
  The Lagrangian velocity structure functions in the inertial range of fully
developed fluid turbulence are derived basing on the Navier-Stokes equations.
For time $\tau$ much smaller than the correlation time, the structure functions
are shown to obey the scaling relations $K_n(\tau)\propto \tau^{\zeta_n}$. The
scaling exponents $\zeta_n$ are calculated analytically. The obtained values
are in amazing agreement with the unique experimental results of the
Bodenschatz group \cite{Bod2}. New notion -- the Lagrangian position structure
functions $R_n(\tau)$ is introduced.
  All the $R_n$ of the order $n>3$ are shown to have a universal scaling.


title: Black hole entropy and the holographic principle

abstract:
  Black holes monopolize nowadays the center stage of fundamental physics. Yet,
they are poorly understood objects. Notwithstanding, from their generic
properties, one can infer important clues to what a fundamental theory, a
theory that includes gravitation and quantum mechanics, should give. Here we
review the classical properties of black holes and their associated event
horizons, as well as the quantum and thermodynamic properties, such as the
temperature, derived from the Hawking radiation, and the entropy. Then, using
the black hole properties we discuss a universal bound on the entropy for any
object, or for any given region of spacetime, and finally we present the
arguments, first given by 't Hooft, that, associating entropy with the number
of quantum degrees of freedom, i.e., the logarithm of quantum states, via
statistical physics, leads to the conclusion that the degrees of freedom of a
given region are in the area A of the region, rather than in its volume V as
naively could be thought. Surely, a fundamental theory has to take this in
consideration.


title:
A combinatorial interpretation for the identity Sum_{k=0}^{n}
  binom{n}{k} Sum_{j=0}^{k} binom{k}{j}^{3}= Sum_{k=0}^{n}
  binom{n}{k}^{2}binom{2k}{k}

abstract:
  The title identity appeared as Problem 75-4, proposed by P. Barrucand, in
Siam Review in 1975. The published solution equated constant terms in a
suitable polynomial identity. Here we give a combinatorial interpretation in
terms of card deals.


title: Gap solitons in superfluid boson-fermion mixtures

abstract:
  Using coupled equations for the bosonic and fermionic order parameters, we
construct families of gap solitons (GSs) in a nearly one-dimensional Bose-Fermi
mixture trapped in a periodic optical-lattice (OL) potential, the boson and
fermion components being in the states of the BEC and BCS superfluid,
respectively. Fundamental GSs are compact states trapped, essentially, in a
single cell of the lattice. Full families of such solutions are constructed in
the first two bandgaps of the OL-induced spectrum, by means of variational and
numerical methods, which are found to be in good agreement. The families
include both intra-gap and inter-gap solitons, with the chemical potentials of
the boson and fermion components falling in the same or different bandgaps,
respectively.Nonfundamental states, extended over several lattice cells, are
constructed too. The GSs are stable against strong perturbations.


title:
First-principle calculation of the dielectric and dynamical properties
  of orthorhombic CaMnO$_{3}$

abstract:
  The structural, dielectric and dynamical properties of the low temperature
antiferromagnetic orthorhombic phase of CaMnO$_3$ have been computed from first
principles using a density functional theory approach within the local spin
density approximation. The theoretical structural parameters are in good
agreement with experiment. The full set of infrared and Raman zone-center
phonons is reported and compared to experimental data. It is shown that
coherently with the anomalous Born effective charges and the presence of low
frequency polar modes, the static dielectric constant is very large and highly
anisotropic.


title: Non-imprisonment conditions on spacetime

abstract:
  The non-imprisonment conditions on spacetimes are studied. It is proved that
the non-partial imprisonment property implies the distinction property.
Moreover, it is proved that feeble distinction, a property which stays between
weak distinction and causality, implies non-total imprisonment. As a result the
non-imprisonment conditions can be included in the causal ladder of spacetimes.
Finally, totally imprisoned causal curves are studied in detail, and results
concerning the existence and properties of minimal invariant sets are obtained.


title: Cosmic ray transport in MHD turbulence

abstract:
  Numerical simulations shed light onto earlier not trackable problem of
magnetohydrodynamic (MHD) turbulence. They allowed to test the predictions of
different models and choose the correct ones. Inevitably, this progress calls
for revisions in the picture of cosmic ray (CR) transport. It also shed light
on the problems with the present day numerical modeling of CR. In this paper we
focus on the analytical way of describing CR propagation and scattering, which
should be used in synergy with the numerical studies. In particular, we use
recently established scaling laws for MHD modes to obtain the transport
properties for CRs. We include nonlinear effects arising from large scale
trapping, to remove the 90 degree divergence. We determine how the efficiency
of the scattering and CR mean free path depend on the characteristics of
ionized media, e.g. plasma $\beta$, Coulomb collisional mean free path.
Implications for particle transport in interstellar medium and solar corona are
discussed. We also examine the perpendicular transport of CRs. Perpendicular
transport depends on the comparison of parallel mean free path and the
injection scale of the turbulence, as well as the Alfv\'enic Mach number.
Normal turbulence does not allow subdiffusion unless there are slab waves. The
critical scale below which subdiffusion applies is provided. These results can
be used to compare with the numerical calculations, provided that these
calculations use the structure of magnetic field which is consistent with the
numerical studies of MHD turbulence.


title: A characterization of regular tetrahedra in Z^3

abstract:
  In this note we characterize all regular tetrahedra whose vertices in R^3
have integer coordinates. The main result is a consequence of the
characterization of all equilateral triangles having integer coordinates
contained in previous work. Then we use this characterization to point out some
corollaries. The number of such tetrahedra whose vertices are in the finite set
{0,1,2,...,n}^3, n in N, is related to the sequence A103158 in the Online
Encyclopedia of Integer Sequences.


title: Noisy heteroclinic networks

abstract:
  We consider a white noise perturbation of dynamics in the neighborhood of a
heteroclinic network. We show that under the logarithmic time rescaling the
diffusion converges in distributon in a special topology to a piecewise
constant process that jumps between saddle points along the heteroclinic orbits
of the network. We also obtain precise asymptotics for the exit measure for a
domain containing the starting point of the diffusion.


title: On rime Ansatz

abstract:
  The ice Ansatz on matrix solutions of the Yang-Baxter equation is weakened to
a condition which we call rime. Generic rime solutions of the Yang-Baxter
equation are described. We prove that the rime non-unitary (respectively,
unitary) R-matrix is equivalent to the Cremmer-Gervais (respectively, boundary
Cremmer-Gervais) solution. Generic rime classical r-matices satisfy the
(non-)homogeneous associative classical Yang-Baxter equation.


title: Cyclic systems of simultaneous congruences

abstract:
  This paper considers solutions (x_1, x_2, ..., x_n) to the cyclic system of n
simultaneous congruences r (x_1x_2 ...x_n)/x_i = s (mod |x_i|), for fixed
nonzero integers r,s with r>0 and gcd(r,s)=1. It shows this system has a finite
number of solutions in positive integers x_i >1 having gcd(x_1x_2...x_n, s)=1,
obtaining a sharp upper bound on the maximal size of the solutions in many
cases. This bound grows doubly-exponentially in n. It shows there are
infinitely many such solutions when the positivity restriction is dropped, when
r=1, and not otherwise. The problem is reduced to the study of integer
solutions of a three parameter family of Diophantine equations r(1/x_1 + 1/x_2
+ ...+ 1/x_n)- s/(x_1x_2...x_n) = m, with parameters (r,s,m).


title:
Build-up of coherence between initially-independent subsystems: The case
  of Bose-Einstein condensates

abstract:
  When initially-independent subsystems are made to contact, {\it coherence}
can develop due to interaction between them. We exemplify and demonstrate this
paradigm through several scenarios of two initially-independent Bose-Einstein
condensates which are allowed to collide. The build-up of coherence depends
strongly on time, interaction strength and other parameters of each condensate.
Implications are discussed.


title: On a Theorem of Sewell and Trotter

abstract:
  Sewell and Trotter [J. Combin. Theory Ser. B, 1993] proved that every
connected alpha-critical graph that is not isomorphic to K_1, K_2 or an odd
cycle contains a totally odd K_4-subdivision. Their theorem implies an
interesting min-max relation for stable sets in graphs without totally odd
K_4-subdivisions. In this note, we give a simpler proof of Sewell and Trotter's
theorem.


title:
A Survey of Compact Star Clusters in the S-W Field of the M31 Disk.
  Structural Parameters. II

abstract:
  The King and the EFF (Elson, Fall & Freeman 1987) analytical models are
employed to determine the structural parameters of star clusters using an 1-D
surface brightness profile fitting method. The structural parameters are
derived and a catalogue is provided for 51 star cluster candidates from the
survey of compact star clusters in the South-West field of the M31 disk
performed by Kodaira et al. (2004).