title: Critical Solutions of Three Vortex Motion in the Parabolic Case

abstract:
  Grobli (1877) laid the foundation for the analysis of the motion of three
point vortices in a plane by deriving governing equations for triangular
configurations of the vortices. Synge (1949) took this formulation one step
further to that of a similar triangle of unit perimeter, via trilinear
coordinates. The final reduced problem is governed by an integrable
two-dimensional system of differential equations with solutions represented as
planar trajectories. Another key to Synge's analysis was his classification of
the problem into three distinct cases: elliptic, hyperbolic and parabolic
corresponding, respectively, to the sum of products of pairs of vortex
strengths being positive, negative or zero. The reduction of the vortex
configuration, a curve in space to a planar curve is one-to-one, except along a
critical planar curve C in the parabolic case. Each point on C represents a
triangle of unit perimeter corresponding to a family of similar vortex
configurations, expanding or contracting. The latter would lead to coelescence
of the three vortices. Tavantzis and Ting (1988) filled most of the gaps left
by Synge regarding the dynamics of the problem, and showed in particular that
points on C corresponding to similar expanding families of vortex
configurations are stable while those corresponding to similar contracting
families are unstable. Their investigations yielded an exhaustive description
of the motion and stability of three vortices in a plane except for the global
behavior of the vortex configurations in a narrow strip containing C. The main
contribution of this paper is a complete description of the global dynamics in
such a strip, which emphaticallly demonstrates that three distinct vortices
almost never coalesce.


title:
Poisson Statistics for Eigenvalues of Continuum Random Schr\"odinger
  Operators

abstract:
  We show absence of energy levels repulsion for the eigenvalues of random
Schr\"odinger operators in the continuum. We prove that, in the localization
region at the bottom of the spectrum, the properly rescaled eigenvalues of a
continuum Anderson Hamiltonian are distributed as a Poisson point process with
intensity measure given by the density of states. We also obtain simplicity of
the eigenvalues. We derive a Minami estimate for continuum Anderson
Hamiltonians. We also give a simple and transparent proof of Minami's estimate
for the (discrete) Anderson model.


title:
Chaos, Determinacy and Fractals in Active-Sterile Neutrino Oscillations
  in the Early Universe

abstract:
  The possibility of light sterile neutrinos allows for the resonant production
of lepton number in the early universe through matter-affected neutrino mixing.
For a given a mixing of the active and sterile neutrino states it has been
found that the lepton number generation process is chaotic and strongly
oscillatory. We undertake a new study of this process' sensitivity to initial
conditions through the quantum rate equations. We confirm the chaoticity of the
process in this solution, and moreover find that the resultant lepton number
and the sign of the asymmetry produces a fractal in the parameter space of
mass, mixing angle and initial baryon number. This has implications for future
searches for sterile neutrinos, where arbitrary high sensitivity could not be
determinate in forecasting the lepton number of the universe.


title: Boom and Bust Inflation: a Graceful Exit via Compact Extra Dimensions

abstract:
  A model of inflation is proposed in which compact extra dimensions allow a
graceful exit without recourse to flat potentials or super-Planckian field
values. Though bubbles of true vacuum are too sparse to uniformly reheat the
Universe by colliding with each other, a compact dimension enables a single
bubble to uniformly reheat by colliding with itself. This mechanism, which
generates an approximately scale invariant perturbation spectrum, requires that
inflation be driven by a bulk field, that vacuum decay be slow, and that the
extra dimension be at least a hundred times larger than the false vacuum Hubble
length.


title: Isoscalar g Factors of Even-Even and Odd-Odd Nuclei

abstract:
  We consider T=0 states in even-even and odd-odd N=Z nuclei. The g factors
that emerge are isoscalar. We find that the single j shell model gives simple
expressions for these g factors which for even-even nuclei are suprisingly
close to the collective values for K=0 bands. The g factors of many 2+ in
even-even nuclei and 1+ and 3+ states in odd-odd nuclei have g factors close to
0.5.


title:
The scintillation and ionization yield of liquid xenon for nuclear
  recoils

abstract:
  XENON10 is an experiment designed to directly detect particle dark matter. It
is a dual phase (liquid/gas) xenon time-projection chamber with 3D position
imaging. Particle interactions generate a primary scintillation signal (S1) and
ionization signal (S2), which are both functions of the deposited recoil energy
and the incident particle type. We present a new precision measurement of the
relative scintillation yield \leff and the absolute ionization yield Q_y, for
nuclear recoils in xenon. A dark matter particle is expected to deposit energy
by scattering from a xenon nucleus. Knowledge of \leff is therefore crucial for
establishing the energy threshold of the experiment; this in turn determines
the sensitivity to particle dark matter. Our \leff measurement is in agreement
with recent theoretical predictions above 15 keV nuclear recoil energy, and the
energy threshold of the measurement is 4 keV. A knowledge of the ionization
yield \Qy is necessary to establish the trigger threshold of the experiment.
The ionization yield \Qy is measured in two ways, both in agreement with
previous measurements and with a factor of 10 lower energy threshold.


title:
Gravitational fragmentation and the formation of brown dwarfs in stellar
  clusters

abstract:
  We investigate the formation of brown dwarfs and very low-mass stars through
the gravitational fragmentation of infalling gas into stellar clusters. The
gravitational potential of a forming stellar cluster provides the focus that
attracts gas from the surrounding molecular cloud. Structures present in the
gas grow, forming filaments flowing into the cluster centre. These filaments
attain high gas densities due to the combination of the cluster potential and
local self-gravity. The resultant Jeans masses are low, allowing the formation
of very low-mass fragments. The tidal shear and high velocity dispersion
present in the cluster preclude any subsequent accretion thus resulting in the
formation of brown dwarfs or very low-mass stars. Ejections are not required as
the brown dwarfs enter the cluster with high relative velocities, suggesting
that their disc and binary properties should be similar to that of low-mass
stars. This mechanism requires the presence of a strong gravitational potential
due to the stellar cluster implying that brown dwarf formation should be more
frequent in stellar clusters than in distributed populations of young stars.
Brown dwarfs formed in isolation would require another formation mechanism such
as due to turbulent fragmentation.


title: Pion LINAC as an Energy-Tagged Neutrino Source

abstract:
  The energy spectrum and flux of neutrinos from a linear pion accelerator are
calculated analytically under the assumption of a uniform accelerating
gradient. The energy of a neutrino from this source reacting in a detector can
be determined from timing and event position information.


title: On the complexity of finding a sun in a graph

abstract:
  The sun is the graph obtained from a cycle of length even and at least six by
adding edges to make the even-indexed vertices pairwise adjacent. Suns play an
important role in the study of strongly chordal graphs. A graph is chordal if
it does not contain an induced cycle of length at least four. A graph is
strongly chordal if it is chordal and every even cycle has a chord joining
vertices whose distance on the cycle is odd. Farber proved that a graph is
strongly chordal if and only if it is chordal and contains no induced suns.
There are well known polynomial-time algorithms for recognizing a sun in a
chordal graph. Recently, polynomial-time algorithms for finding a sun for a
larger class of graphs, the so-called HHD-free graphs, have been discovered. In
this paper, we prove the problem of deciding whether an arbitrary graph
contains a sun in NP-complete.


title: The Postage Stamp Problem and Essential Subsets in Integer Bases

abstract:
  Plagne recently determined the asymptotic behavior of the function E(h),
which counts the maximum possible number of essential elements in an additive
basis for N of order h. Here we extend his investigations by studying
asymptotic behavior of the function E(h,k), which counts the maximum possible
number of essential subsets of size k, in a basis of order h. For a fixed k and
with h going to infinity, we show that E(h,k) = \Theta_{k} ([h^{k}/\log
h]^{1/(k+1)}). The determination of a more precise asymptotic formula is shown
to depend on the solution of the well-known "postage stamp problem" in finite
cyclic groups. On the other hand, with h fixed and k going to infinity, we show
that E(h,k) \sim (h-1) {\log k \over \log \log k}.


title:
Optimal ISW detection and joint likelihood for cosmological parameter
  estimation

abstract:
  We analyse the local variance effect in the standard method for detecting the
integrated Sachs-Wolfe effect (ISW) via cross-correlating the cosmic microwave
background (CMB) with the large-scale structure (LSS). Local variance is
defined as the systematic noise in the ISW detection that originates in the
realisation of the matter distribution in the observed Universe. We show that
the local variance contributes about 11 per cent to the total variance in the
standard method, if a perfect and complete LSS survey up to z ~ 2 is assumed.
Due to local variance, the estimated detection significance and cosmological
parameter constraints in the standard method are biased. In this work, we
present an optimal method of how to reduce the local variance effect in the ISW
detection by working conditional on the LSS-data. The variance of the optimal
method, and hence the signal-to-noise ratio, depends on the actual realisation
of the matter distribution in the observed Universe. We show that for an ideal
galaxy survey, the average signal-to-noise ratio is enhanced by about 7 per
cent in the optimal method, as compared to the standard method. Furthermore, in
the optimal method there is no need to estimate the covariance matrix by Monte
Carlo simulations as in the standard method, which saves time and increases the
accuracy. Finally, we derive the correct joint likelihood function for
cosmological parameters given CMB- and LSS-data within the linear LSS formation
regime, which includes a small coupling of the two datasets due to the ISW
effect.


title: Quaternionic contact normal coordinates

abstract:
  This paper constructs a family of coordinate systems about a point on a
quaternionic contact manifold, called quaternionic contact pseudohermitian
normal coordinates. Once defined, conformal variations of the quaternionic
contact structure induce changes on the coordinates which are studied in an
effort to simplify the torsion and curvature at the center point.


title: Quantum phase transitions and new scales in QCD-like theories

abstract:
  It is commonly believed that in confining vector-like gauge theories the
center and chiral symmetry realizations are parametrically entangled, and if
phase transitions occur, they must take place around the strong scale
$\Lambda^{-1}$ of the gauge theory. We demonstrate that (non-thermal)
vector-like theories formulated on ${\mathbb R}^{3} \times S^1$ where $S^1$ is
a spatial circle exhibit new dynamical scales and new phenomena. There are
chiral phase transitions taking place at $\Lambda^{-1}/N_c$ in the absence of
any change in center symmetry. $\Lambda^{-1}/N_c$, invisible in (planar)
perturbation theory, is also the scale where abelian versus non-abelian
confinement regimes meet. Large $N_c$ volume independence (a working
Eguchi-Kawai reduction) provides new insights and independently confirms the
existence of these scales. We show that certain phases and scales are outside
the reach of holographic (supergravity) modeling of QCD.


title:
Limits on the Superconducting Order Parameter in NdFeAsO$_{1-x}$F$_y$
  from Scanning SQUID Microscopy

abstract:
  Identifying the symmetry of the superconducting order parameter in the
recently-discovered ferro-oxypnictide family of superconductors,
RFeAsO$_{1-x}$F$_{y}$, where $R$ is a rare earth, is a high priority. Many of
the proposed order parameters have internal $\pi$ phase shifts, like the d-wave
order found in the cuprates, which would result in direction-dependent phase
shifts in tunnelling. In dense polycrystalline samples, these phase shifts in
turn would result in spontaneous orbital currents and magnetization in the
superconducting state. We perform scanning SQUID microscopy on a dense
polycrystalline sample of \NdFeAsO$_{0.94}$F$_{0.06}$ with $T_c=48$ K and find
no such spontaneous currents, ruling out many of the proposed order parameters.


title: Computing points of small height for cubic polynomials

abstract:
  Let f in Q[z] be a polynomial of degree d at least two. The associated
canonical height \hat{h}_f is a certain real-valued function on Q that returns
zero precisely at preperiodic rational points of f. Morton and Silverman
conjectured in 1994 that the number of such points is bounded above by a
constant depending only on d. A related conjecture claims that at
non-preperiodic rational points, \hat{h}_f is bounded below by a positive
constant (depending only on d) times some kind of height of f itself. In this
paper, we provide support for these conjectures in the case d=3 by computing
the set of small height points for several billion cubic polynomials.


title: SuperLupus: A Deep, Long Duration Transit Survey

abstract:
  SuperLupus is a deep transit survey monitoring a Galactic Plane field in the
Southern hemisphere. The project is building on the successful Lupus Survey,
and will double the number of images of the field from 1700 to 3400, making it
one of the longest duration deep transit surveys. The immediate motivation for
this expansion is to search for longer period transiting planets (5-8 days) and
smaller radii planets. It will also provide near complete recovery for the
shorter period planets (1-3 days). In March, April, and May 2008 we obtained
the new images and work is currently in progress reducing these new data.


title:
First-principles study of the spin-lattice coulpling in spin frustrated
  DyMn$_2$O$_5$

abstract:
  The lattice dynamic properties and spin-phonon coupling in DyMn$_2$O$_5$ are
studied by using the density-functional theory. The calculated phonon
frequencies are in very good agreement with experiments. We then compare the
phonon modes calculated from different spin configurations. The results show
that the phonon frequencies change substantially in different spin
configurations, suggesting that the spin-phonon coupling in this material is
very strong. Especially, the short range spin ordering has drastic effects on
the highest Raman and IR phonon modes that might be responsible for the
observed phonon anomalies near and above the magnetic phase transitions.


title: Complete intersection Approximation, Dual Filtrations and Applications

abstract:
  We give a two step method to study certain questions regarding associated
graded module of a Cohen-Macaulay (CM) module $M$ w.r.t an
$\mathfrak{m}$-primary ideal $\mathfrak{a}$ in a complete Noetherian local ring
$(A,\mathfrak{m})$. The first step, we call it complete intersection
approximation, enables us to reduce to the case when both $A$, $
G_\mathfrak{a}(A) = \bigoplus_{n \geq 0} \mathfrak{a}^n/\mathfrak{a}^{n+1} $
are complete intersections and $M$ is a maximal CM $A$-module. The second step
consists of analyzing the classical filtration $\{Hom_A(M,\mathfrak{a}^n)
\}_{\mathbb{Z}}$ of the dual $Hom_A(M,A)$. We give many applications of this
point of view. For instance let $(A,\mathfrak{m})$ be equicharacteristic and
CM. Let $a(G_\mathfrak{a}(A))$ be the $a$-invariant of $G_\mathfrak{a}(A)$. We
prove:
  1. $a(G_\mathfrak{a}(A)) = -\dim A$ iff $\mathfrak{a}$ is generated by a
regular sequence.
  2. If $\mathfrak{a}$ is integrally closed and $a(G_\mathfrak{a}(A)) = -\dim A
+ 1$ then $\mathfrak{a}$ has minimal multiplicity.
  We extend to modules a result of Ooishi relating symmetry of $h$-vectors. As
another application
  we prove a conjecture of Itoh, if $A$ is a CM local ring and
  $\mathfrak{a}$ is a normal ideal with $e_3^\mathfrak{a}(A) = 0$ then
$G_\mathfrak{a}(A)$ is CM.


title:
Response to "Comment on Ferroelectrically induced weak ferromagnetism by
  design," by R. de Sousa and J. E. Moore, arXiv:0806.2142

abstract:
  A recent Comment [arXiv:0806.2142] has argued that "there is a simple duality
between A-site and B-site" R3c ABO$_3$ materials and that our Letter [PRL 100,
167203 (2208)] "breaks this duality by ignoring a non-polar distortion that is
directly measured in crystallography." Here we point out that this is not
correct. The Comment contains three elementary crystallographic errors. In this
response we address each error in some detail.


title: NGC 2770 - a supernova Ib factory?

abstract:
  NGC 2770 has been the host of three supernovae of Type Ib during the last 10
years, SN 1999eh, SN 2007uy and SN 2008D. SN 2008D attracted special attention
due to the serendipitous discovery of an associated X-ray transient. In this
paper, we study the properties of NGC 2770 and specifically the three SN sites
to investigate whether this galaxy is in any way peculiar to cause a high
frequency of SNe Ib. We model the global SED of the galaxy from broadband data
and derive a star-formation and SN rate comparable to the values of the Milky
Way. We further study the galaxy using longslit spectroscopy covering the major
axis and the three SN sites. From the spectroscopic study we find subsolar
metallicities for the SN sites, a high extinction and a moderate star-formation
rate. In a high resolution spectrum, we also detect diffuse interstellar bands
in the line-of-sight towards SN 2008. A comparison of NGC 2770 to the global
properties of a galaxy sample with high SN occurance (at least 3 SN in the last
100 years) suggests that NGC 2770 is not particularly destined to produce such
an enhancement of observed SNe observed. Its properties are also very different
from gamma-ray burst host galaxies. Statistical considerations on SN Ib
detection rates give a probability of ~1.5% to find a galaxy with three Ib SNe
detected in 10 years. The high number of rare Ib SNe in this galaxy is
therefore likely to be a coincidence rather than special properties of the
galaxy itself. NGC 2770 has a small irregular companion, NGC 2770B, which is
highly starforming, has a very low mass and one of the lowest metallicities
detected in the nearby universe as derived from longslit spectroscopy. In the
most metal poor part, we even detect Wolf-Rayet features, against the current
models of WR stars which require high metallicities.


title: Stratified Steady Periodic Water Waves

abstract:
  This paper considers two-dimensional stratified water waves propagating under
the force of gravity over an impermeable flat bed and with a free surface. We
prove the existence of a global continuum of classical solutions that are
periodic and traveling. These waves, moreover, can exhibit large density
variation, speed and amplitude.


title: Color, 3D simulated images with shapelets

abstract:
  We present a method to simulate color, 3-dimensional images taken with a
space-based observatory by building off of the established shapelets pipeline.
The simulated galaxies exhibit complex morphologies, which are realistically
correlated between, and include, known redshifts. The simulations are created
using galaxies from the 4 optical and near-infrared bands (B, V, i and z) of
the Hubble Ultra Deep Field (UDF) as a basis set to model morphologies and
redshift. We include observational effects such as sky noise and pixelization
and can add astronomical signals of interest such as weak gravitational
lensing. The realism of the simulations is demonstrated by comparing their
morphologies to the original UDF galaxies and by comparing their distribution
of ellipticities as a function of redshift and magnitude to wider HST COSMOS
data. These simulations have already been useful for calibrating multicolor
image analysis techniques and for better optimizing the design of proposed
space telescopes.


title:
Research report: State complexity of operations on two-way quantum
  finite automata

abstract:
  This paper deals with the size complexity of minimal {\it two-way quantum
finite automata} (2qfa's) necessary for operations to perform on all inputs of
each fixed length. Such a complexity measure, known as state complexity of
operations, is useful in measuring how much information is necessary to convert
languages. We focus on intersection, union, reversals, and catenation
operations and show some upper bounds of state complexity of operations on
2qfa's. Also, we present a number of non-regular languages and prove that these
languages can be accepted by 2qfa's with one-sided error probabilities within
linear time. Notably, these examples show that our bounds obtained for these
operations are not tight, and therefore worth improving. We give an instance to
show that the upper bound of the state number for the simulation of one-way
deterministic finite automata by two-way reversible finite automata is not
tight in general.


title:
What kinds of coordinate can keep the Hawking temperature invariant for
  the static spherically symmetric black hole?

abstract:
  By studying the Hawking radiation of the most general static spherically
symmetric black hole arising from scalar and Dirac particles tunnelling, we
find the Hawking temperature is invariant in the general coordinate
representation (\ref{arbitrary1}), which satisfies two conditions: a) its
radial coordinate transformation is regular at the event horizon; and b) there
is a time-like Killing vector.


title: Low-lying Proton Intruder State in 13B

abstract:
  The neturon rich nucleus 13B was studied via the proton transfer reaction
4He(12Be,13B \gamma) at 50AMeV. The known 4.83-MeV excited state was strongly
populated and its spin and parity were assigned to 1/2+ by comparing the
angular differential cross section data with DWBA calculations. This low-lying
1/2+ state is interpreted as a proton intruder state and indicates a
deformation of the nucleus.


title: Parametric interaction and intensification of nonlinear Kelvin waves

abstract:
  Observational evidence is presented for nonlinear interaction between
mesoscale internal Kelvin waves at the tidal -- $\omega_t$ or the inertial --
$\omega_i$ frequency and oscillations of synoptic -- $\Omega $ frequency of the
background coastal current of Japan/East Sea. Enhanced coastal currents at the
sum -- $\omega_+ $ and dif -- $\omega_-$ frequencies: $\omega_\pm
=\omega_{t,i}\pm \Omega$ have properties of propagating Kelvin waves suggesting
permanent energy exchange from the synoptic band to the mesoscale $\omega_\pm $
band. The interaction may be responsible for the greater than predicted
intensification, steepen and break of boundary trapped and equatorially trapped
Kelvin waves, which can affect El Ni\~{n}o. The problem on the parametric
interaction of the nonlinear Kelvin wave at the frequency $\omega $ and the
low-frequency narrow-band nose with representative frequency $\Omega\ll\omega $
is investigated with the theory of nonlinear week dispersion waves.


title: Decontracted double BRST on the lattice

abstract:
  We present the Curci-Ferrari model on the lattice. In the massless case the
topological interpretation of this model with its double BRST symmetry relates
to the Neuberger 0/0 problem which we extend to include the ghost/anti-ghost
symmetric formulation of the non-linear covariant Curci-Ferrari gauges on the
lattice. The introduction of a Curci-Ferrari mass term, however, serves to
regulate the 0/0 indeterminate form of physical observables observed by
Neuberger. While such a mass m decontracts the double BRST/anti-BRST algebra,
which is well-known to result in a loss of unitarity, observables can be
meaningfully defined in the limit m to 0 via l'Hospital's rule. At finite m the
topological nature of the partition function used as the gauge fixing device
seems lost. We discuss the gauge parameter xi and mass m dependence of the
model and show how both cancel when m = m(xi) is appropriately adjusted with
xi.


title: Minimal Supersymmetric Left-Right Model with Automatic R Parity

abstract:
  We revisit the minimal supersymmetric left-right model with B-L=2 triplet
Higgs fields and show that a self-consistent picture emerges with automatic
R-parity conservation even in the absence of higher dimensional operators. By
computing the effective potential for the Higgs system including heavy Majorana
neutrino Yukawa couplings we show that the global minimum of the model can lie
in the charge and R-parity conserving domain. The model provides natural
solutions to the SUSY phase problem and the strong CP problem and makes several
interesting predictions. Quark mixing angles arise only after radiative
corrections from the lepton sector are taken into account. A pair of doubly
charged Higgs fields remain light below TeV with one field acquiring its mass
entirely via renormalization group corrections. We find this mass to be not
much above the Bino mass. In the supergravity framework for SUSY breaking, we
also find similar upper limits on the stau masses. Natural solutions to the
$\mu$ problem and the SUSY CP problem entails light SU(2)_L triplet Higgs
fields, leading to rich collider phenomenology.


title: CR manifolds admitting a CR contraction

abstract:
  We classify the germs of $\mathcal{C}^\infty$ CR manifolds that admit a
smooth CR contraction. We show that such a CR manifold is embedded into $\CC^n$
as a real hypersurface defined by a polynomial defining function consisting of
monomials whose degrees are completely determined by the extended resonances of
the contraction. Furthermore the contraction map extends to a holomorphic
contraction that coincides in fact with its polynomial normal form.
Consequently, several results concerning Complex and CR geometry are derived.


title: The Age-Specific Force of Natural Selection and Walls of Death

abstract:
  W. D. Hamilton's celebrated formula for the age-specific force of natural
selection furnishes predictions for senescent mortality due to mutation
accumulation, at the price of reliance on a linear approximation. Applying to
Hamilton's setting the full non-linear demographic model for mutation
accumulation of Evans et al. (2007), we find surprising differences. Non-linear
interactions cause the collapse of Hamilton-style predictions in the most
commonly studied case, refine predictions in other cases, and allow Walls of
Death at ages before the end of reproduction. Haldane's Principle for genetic
load has an exact but unfamiliar generalization.


title:
Improved bounds and new techniques for Davenport-Schinzel sequences and
  their generalizations

abstract:
  Let lambda_s(n) denote the maximum length of a Davenport-Schinzel sequence of
order s on n symbols. For s=3 it is known that lambda_3(n) = Theta(n alpha(n))
(Hart and Sharir, 1986). For general s>=4 there are almost-tight upper and
lower bounds, both of the form n * 2^poly(alpha(n)) (Agarwal, Sharir, and Shor,
1989). Our first result is an improvement of the upper-bound technique of
Agarwal et al. We obtain improved upper bounds for s>=6, which are tight for
even s up to lower-order terms in the exponent. More importantly, we also
present a new technique for deriving upper bounds for lambda_s(n). With this
new technique we: (1) re-derive the upper bound of lambda_3(n) <= 2n alpha(n) +
O(n sqrt alpha(n)) (first shown by Klazar, 1999); (2) re-derive our own new
upper bounds for general s; and (3) obtain improved upper bounds for the
generalized Davenport-Schinzel sequences considered by Adamec, Klazar, and
Valtr (1992). Regarding lower bounds, we show that lambda_3(n) >= 2n alpha(n) -
O(n), and therefore, the coefficient 2 is tight. We also present a simpler
version of the construction of Agarwal, Sharir, and Shor that achieves the
known lower bounds for even s>=4.


title:
The Weibull - Log Weibull Distribution for Interoccurrence Times of
  Earthquakes

abstract:
  By analyzing the Japan Meteorological Agency (JMA) seismic catalog for
different tectonic settings, we have found that the probability distributions
of time intervals between successive earthquakes --interoccurrence times-- can
be described by the superposition of the Weibull distribution and the
log-Weibull distribution. In particular, the distribution of large earthquakes
obeys the Weibull distribution with the exponent $\alpha_1 <1$, indicating the
fact that the sequence of large earthquakes is not a Poisson process. It is
found that the ratio of the Weibull distribution to the probability
distribution of the interoccurrence time gradually increases with increase in
the threshold of magnitude. Our results infer that Weibull statistics and
log-Weibull statistics coexist in the interoccurrence time statistics, and that
the change of the distribution is considered as the change of the dominant
distribution. In this case, the dominant distribution changes from the
log-Weibull distribution to the Weibull distribution, allowing us to reinforce
the view that the interoccurrence time exhibits the transition from the Weibull
regime to the log-Weibull regime.


title: Topologically Massive AdS Gravity

abstract:
  We analyze (2+1)-dimensional gravity with a Chern--Simons term and a negative
cosmological constant, primarily at the weak field level. The full theory is
expressible as the sum of two higher derivative SL(2,R) "vector" Chern-Simons
terms, while the physical bulk degrees of freedom correspond to a single
massive scalar field, just as for Lambda=0. The interplay of Lambda and the
mass parameter mu can be studied, and any physical mass--including the
conformal value with null propagation--is accessible by tuning mu. The single
bulk mode yields a complete set of normalizable positive energy wave packets,
as long as one chooses the usual, "wrong" sign of G necessary to connect
smoothly with the known Lambda=0 limit. The chiral Chern--Simons coupling leads
to gauge invariant linearized curvatures propagating with chirality-dependent
masses. Linearized metric fluctuations have a finite asymptotic
Fefferman--Graham expansion about the Poincar'e metric for any mass value
greater or equal to a "critical" one, where various amusing effects appear,
such as vanishing of one of the two "vector" Chern-Simons terms and an
equivalence between tensor and vector excitations. We also find a set of
chiral, pp-wave metrics that exactly solve the full nonlinear equations.


title: Low-energy effective theory of the toric code model in a parallel field

abstract:
  We determine analytically the phase diagram of the toric code model in a
parallel magnetic field which displays three distinct regions. Our study relies
on two high-order perturbative expansions in the strong- and weak-field limit,
as well as a large-spin analysis. Calculations in the topological phase
establish a quasiparticle picture for the anyonic excitations. We obtain two
second-order transition lines that merge with a first-order line giving rise to
a multicritical point as recently suggested by numerical simulations. We
compute the values of the corresponding critical fields and exponents that
drive the closure of the gap. We also give the one-particle dispersions of the
anyonic quasiparticles inside the topological phase.


title:
Vortex qubit based on an annular Josephson junction containing a
  microshort

abstract:
  We report theoretical and experimental work on the development of a vortex
qubit based on a microshort in an annular Josephson junction. The microshort
creates a potential barrier for the vortex, which produces a double-well
potential under the application of an in-plane magnetic field; The field
strength tunes the barrier height. A one-dimensional model for this system is
presented, from which we calculate the vortex depinning current and attempt
frequency as well as the interwell coupling. Implementation of an effective
microshort is achieved via a section of insulating barrier that is locally
wider in the junction plane. Using a junction with this geometry we demonstrate
classical state preparation and readout. The vortex is prepared in a given
potential well by sending a series of "shaker" bias current pulses through the
junction. Readout is accomplished by measuring the vortex depinning current.


title: Partons and jets at strong coupling from AdS/CFT

abstract:
  Calculations using the AdS/CFT correspondence can be used to unveil the
short-distance structure of a strongly coupled plasma, as it would be seen by a
`hard probe'. The results of these calculations admit a natural physical
interpretation in terms of parton evolution in the plasma: via successive
branchings, essentially all partons cascade down to very small values of the
longitudinal momentum fraction x and to transverse momenta smaller than the
saturation momentum Q_s\sim T/x. This scale Q_s controls the energy loss and
the transverse momentum broadening of an energetic jet propagating through the
plasma. This picture has some striking consequences, like the absence of jets
in electron-proton annihilation at strong coupling, of the absence of particle
production at forward and backward rapidities in hadron-hadron collisions,
which look very different from the corresponding predictions of perturbative
QCD and also from the known experimental situation.


title: Effective Theories and Electroweak Precision Constraints

abstract:
  This is a pedagogical and self-contained review on obtaining electroweak
precision constraints on TeV scale new physics using the effective theory
method. We identify a set of relevant effective operators in the standard model
and calculate from them corrections to all major electroweak precision
observables. The corrections are compared with data to put constraints on the
effective operators. Various approaches and applications in the literature are
reviewed.


title: Combinatorial computation of the motivic Poincare series

abstract:
  We give the explicit algorithm computing the motivic generalization of the
Poincare series of the plane curve singularity introduced by A. Campillo, F.
Delgado and S. Gusein-Zade. It is done in terms of the embedded resolution of
the curve. The result is a rational function depending of the parameter q, at
q=1 it coincides with the Alexander polynomial of the corresponding link. For
irreducible curves we relate this invariant to the Heegard-Floer knot
homologies constructed by P. Ozsvath and Z. Szabo. Many explicit examples are
considered.


title:
Curves without automorphisms and integral invariants of Calabi-Yau
  three-folds

abstract:
  This paper has been withdrawn by the author, due a crucial mistake in proof
of lemma 4.2.


title:
Resonant sequential scattering in two-frequency-pumping superradiance
  from a Bose-Einstein condensate

abstract:
  We study sequential scattering in superradiance from a Bose-Einstein
condensate pumped by a two-frequency laser beam. We find that the distribution
of atomic side modes presents highly different patterns for various frequency
difference between the two pump components. A novel distribution is observed,
with a frequency difference of eight times the recoil frequency. These
observations reveal that the frequency overlap between the end-fire modes
related to different side modes plays an essential role in the dynamics of
sequential superradiant scattering. The numerical results from a semiclassical
model qualitatively agree with our observations.


title:
Anomalous Line-Shape of Cross Sections for $e^+e^- \to {\rm Hadrons}$ in
  the Center-of-Mass Energy Region between 3.650 and 3.872 GeV

abstract:
  We observe an obvious anomalous line-shape of the $e^+e^- \to {\rm hadrons}$
total cross sections in the energy region between 3.700 and 3.872 GeV from the
data samples taken with the BES-II detector at the BEPC Collider. Re-analysis
of the data shows that it is inconsistent with the explanation for only one
simple $\psi(3770)$ resonance with a statistical significance of $7\sigma$. The
anomalous line-shape may be explained by two possible enhancements of the
inclusive hadron production near the center-of-mass energies of 3.764 GeV and
3.779 GeV, indicating that either there is likely a new structure in addition
to the $\psi(3770)$ resonance around 3.773 GeV, or there are some physics
effects reflecting the $D\bar D$ production dynamics.


title:
The spectroscopic variability of T$_{\rm eff}$ and $\log g$ in $\beta$
  Cep

abstract:
  Time resolved spectra of $\beta$ Cep yield the following average results:
T$_{\rm eff}$ =24000 $\pm$ 250 K, $\log g$ = 3.91 $\pm$ 0.05 and $\xi$ = 8.1
$\pm$ 0.9 km s$^{-1}$. N, O, Ne, Al, Si and S abundances are solar while C, Mg
and Fe are slightly under-abundant. Pulsational amplitudes of $\Delta$T$_{\rm
eff}$ $\sim$ 700 K and $\Delta$$\log g$ $\sim$ 0.2 dex are found from H$\beta$.
The metal lines give similar amplitudes but centred on T$_{\rm eff}$ $\sim$
25000 K. An upper limit of 1.0 km s$^{-1}$ to the variability of the
microturbulence is derived from the Si {\sc iii} triplet at 455 nm. The radial
velocity amplitude derived from the core of H$\beta$ is $\sim$ 15% greater than
that from the metal lines.


title: Measurements of the CKM angle phi_1/beta from Belle and BaBar

abstract:
  We report recent measurements of the CKM angle phi_1/beta using large data
samples collected by the Belle and BaBar experiments at the e^+ e^-
asymmetric-energy colliders.


title: AstraLux: the Calar Alto Lucky Imaging Camera

abstract:
  AstraLux is the Lucky Imaging camera for the Calar Alto 2.2-m telescope,
based on an electron-multiplying high speed CCD. By selecting only the best
1-10% of several thousand short exposure frames, AstraLux provides nearly
diffraction limited imaging capabilities in the SDSS i' and z' filters over a
field of view of 24x24 arcseconds. By choosing commercially available
components wherever possible, the instrument could be built in short time and
at comparably low cost. We present the instrument design, the data reduction
pipeline, and summarise the performance and characteristics


title:
Funtional Renormalization Group Study of the Pairing Symmetry and
  Pairing Mechanism of the FeAs Based High Temperature Superconductors

abstract:
  We apply the fermion functional renormalization group method to determine the
pairing symmetry and pairing mechanism of the FeAs-Based materials. Within a
five band model with pure repulsive interactions, we find an electronic-driven
superconducting pairing instability. For the doping and interaction parameters
we have examined, extended s-wave, whose order parameter takes on opposite sign
on the electron and hole pockets, is always the most favorable pairing
symmetry. The pairing mechanism is the inter Fermi surface Josephson scattering
generated by the antiferromagnetic correlation.


title:
Tug-of-war as a cooperative mechanism for bidirectional cargo transport
  by molecular motors

abstract:
  Intracellular transport is based on molecular motors that pull cargos along
cytoskeletal filaments. One motor species always moves in one direction, e.g.
conventional kinesin moves to the microtubule plus end, while cytoplasmic
dynein moves to the microtubule minus end. However, many cellular cargos are
observed to move bidirectionally, involving both plus-end and minus-end
directed motors. The presumably simplest mechanism for such bidirectional
transport is provided by a tug-of-war between the two motor species. This
mechanism is studied theoretically using the load-dependent transport
properties of individual motors as measured in single-molecule experiments. In
contrast to previous expectations, such a tug-of-war is found to be highly
cooperative and to exhibit seven different motility regimes depending on the
precise values of the single motor parameters. The sensitivity of the transport
process to small parameter changes can be used by the cell to regulate its
cargo traffic.


title: Loops for Hot QCD

abstract:
  In this talk we review the status concerning vacuum integrals needed in
perturbative expansions of QCD at non-zero temperature. We will focus on the
differences as compared to familiar zero-temperature techniques, and provide a
list of known basic master integrals.


title: MicroLux: high-precision timing of high-speed photometric observations

abstract:
  MicroLux is a GPS-based high precision and high speed timing add-on to the
Calar Alto Lucky Imaging camera AstraLux. It allows timestamping of individual
CCD exposures at frame rates of more than 1 kHz with an accuracy better than
one microsecond with respect to the UTC timeframe. The system was successfully
used for high speed observations of the optical pulse profile of the Crab
pulsar in January and November 2007. I present the technical design concept of
MicroLux as well as first results from these observations, in particular the
reconstructed pulse profile of the pulsar.


title: Faltings heights of CM cycles and derivatives of L-functions

abstract:
  We study the Faltings height pairing of arithmetic Heegner divisors and CM
cycles on Shimura varieties associated to orthogonal groups. We compute the
Archimedian contribution to the height pairing and derive a conjecture relating
the total pairing to the central derivative of a Rankin L-function. We prove
the conjecture in certain cases where the Shimura variety has dimension 0, 1,
or 2. In particular, we obtain a new proof of the Gross-Zagier formula.


title: $\cos 2 \phi$ asymmetries in unpolarized semi-inclusive DIS

abstract:
  We use the Boer-Mulders functions parameterized from unpolarized $p+D$
Drell-Yan data by the FNAL E866/NuSea Collaboration combined with recently
extracted Collins functions to calculate the $\cos 2 \phi$ asymmetries in
unpolarized semi-inclusive deeply inelastic scattering (SIDIS) processes both
for ZEUS at Hadron Electron Ring Accelerator (HERA) and Jefferson Lab
experiments (JLab), and to compare our results with their data. We also give
predictions for the $\cos 2 \phi$ asymmetries of SIDIS in the kinematical
regime of HERMES Collaboration, and the forthcoming JLab experiments. We
predict that the $\cos 2 \phi$ asymmetries of semi-inclusive $\pi^-$ production
are somewhat larger than that of $\pi^+$ production. We suggest to measure
these two processes separately, which will provide more detail information on
the Boer-Mulders functions as well as on the Collins functions.


title: AstraLux - the Calar Alto 2.2-m telescope Lucky Imaging camera

abstract:
  AstraLux is a Lucky Imaging camera for the Calar Alto 2.2-m telescope, based
on an electron-multiplying high speed CCD. By selecting only the best 1-10% of
several thousand short exposure frames, AstraLux provides nearly diffraction
limited imaging capabilities in the SDSS i' and z' filters over a field of view
of 24x24 arcseconds. By choosing commercially available components wherever
possible, the instrument could be built in short time and at comparably low
cost. We briefly present the instrument design, the data reduction pipeline,
and summarise the performance and characteristics


title:
On a surprising relation between rectangular and square free
  convolutions

abstract:
  Debbah and Ryan have recently proved a result about the limit empirical
singular distribution of the sum of two rectangular random matrices whose
dimensions tend to infinity. In this paper, we reformulate it in terms of the
rectangular free convolution introduced in a previous paper and then we give a
new, shorter, proof of this result under weaker hypothesis: we do not suppose
the \pro measure in question in this result to be compactly supported anymore.
At last, we discuss the inclusion of this result in the family of relations
between rectangular and square random matrices.


title:
Controlling the Population Imbalance of a Bose-Einstein Condensate by a
  Symmetry-Breaking Driving Field

abstract:
  Nonlinear Floquet states associated with a symmetry-breaking driving field
are exploited to control the dynamics of a Bose-Einstein condensate in a
double-well potential. The population imbalance between the two wells is shown
to be controllable by slowly tuning system parameters along a closed path. The
results extend symmetry-breaking-based quantum control to many-body systems and
extend navigation of linear Floquet states to navigation of nonlinear Floquet
states.


title: Gate complexity using Dynamic Programming

abstract:
  The relationship between efficient quantum gate synthesis and control theory
has been a topic of interest in the quantum control literature. Motivated by
this work, we describe in the present article how the dynamic programming
technique from optimal control may be used for the optimal synthesis of quantum
circuits. We demonstrate simulation results on an example system on SU(2), to
obtain plots related to the gate complexity and sample paths for different
logic gates.


title:
Measurements of Stellar Properties through Asteroseismology: A Tool for
  Planet Transit Studies

abstract:
  Oscillations occur in stars of most masses and essentially all stages of
evolution. Asteroseismology is the study of the frequencies and other
properties of stellar oscillations, from which we can extract fundamental
parameters such as density, mass, radius, age and rotation period. We present
an overview of asteroseismic analysis methods, focusing on how this technique
may be used as a tool to measure stellar properties relevant to planet transit
studies. We also discuss details of the Kepler Asteroseismic Investigation --
the use of asteroseismology on the Kepler mission in order to measure basic
stellar parameters. We estimate that applying asteroseismology to stars
observed by Kepler will allow the determination of stellar mean densities to an
accuracy of 1%, radii to 2-3%, masses to 5%, and ages to 5-10% of the
main-sequence lifetime. For rotating stars, the angle of inclination can also
be determined.


title:
A subtraction scheme for computing QCD jet cross sections at NNLO:
  integrating the subtraction terms I

abstract:
  In previous articles we outlined a subtraction scheme for regularizing
doubly-real emission and real-virtual emission in next-to-next-to-leading order
(NNLO) calculations of jet cross sections in electron-positron annihilation. In
order to find the NNLO correction these subtraction terms have to be integrated
over the factorized unresolved phase space and combined with the two-loop
corrections. In this paper we perform the integration of all one-parton
unresolved subtraction terms.


title: Eigenvalue cut-off in the cubic-quintic nonlinear Schrodinger equation

abstract:
  Using theoretical arguments, we prove the numerically well-known fact that
the eigenvalues of all localized stationary solutions of the cubic-quintic 2D+1
nonlinear Schrodinger equation exhibit an upper cut-off value. The existence of
the cut-off is inferred using Gagliardo-Nirenberg and Holder inequalities
together with Pohozaev identities. We also show that, in the limit of
eigenvalues close to zero, the eigenstates of the cubic-quintic nonlinear
Schrodinger equation behave similarly to those of the cubic nonlinear
Schrodinger equation.


title: Electron-phonon interaction in nanodevices

abstract:
  The effect of the up-conversion of the electronic energy level occupation was
earlier interpreted as an implication of the multiple scattering of the charge
carriers on the longitudinal optical phonons of the lattice vibrations in a
small system like a quantum dot. In this work we study the influence of this
effect on the electronic motion in a nanotransistor represented by a quantum
dot connected to two electric wires and a gate electrode. We show that in an
asymmetric nanotransistor the up-conversion effect gives rise to a spontaneous
current between the source and the drain, or to an appearance of a spontaneous
voltage between these electrodes. The effect will be studied basing on the well
known Datta's Toy Model of the theoretical description of the nanotransistor
and on additional kinetic equations giving the multiple scattering of electrons
in the quantum dot, in the self-consistent Born approximation to the electronic
self-energy. We shall also briefly discuss the relation of this theoretical
result to existing experiments on current-voltage characteristics in gated
nanostructures.


title: On the finite cyclicity of open period annuli

abstract:
  Let $\Pi$ be an open, relatively compact period annulus of real analytic
vector field $X_0$ on an analytic surface. We prove that the maximal number of
limit cycles which bifurcate from $\Pi$ under a given multi-parameter analytic
deformation $X_\lambda$ of $X_0$ is finite, provided that $X_0$ is either
Hamiltonian, or generic Darbouxian vector field.


title: Non-Relativistic Conformal and Supersymmetries

abstract:
  Non-relativistic conformal (''Schr\"odinger'') symmetry is derived in a
Kaluza-Klein type framework. Lightlike reduction of the massless Dirac equation
from 5D Minkowski space yields L\'evy-Leblond's non-relativistic equation for a
spin 1/2 particle. Combining with the osp(1,1) SUSY found before provides us
with a super-Schr\"odinger symmetry.


title:
Analytic integration of real-virtual counterterms in NNLO jet cross
  sections I

abstract:
  We present analytic evaluations of some integrals needed to give explicitly
the integrated real-virtual integrated counterterms, based on a recently
proposed subtraction scheme for next-to-next-to-leading order (NNLO) jet cross
sections. After an algebraic reduction of the integrals, integration-by-parts
identities are used for the reduction to master integrals and for the
computation of the master integrals themselves by means of differential
equations. The results are written in terms of one- and two-dimensional
harmonic polylogarithms, once an extension of the standard basis is made. We
expect that the techniques described here will be useful in computing other
integrals emerging in calculations in perturbative quantum field theories.


title: Radiative corrections in K --> 3 pi decays

abstract:
  We investigate radiative corrections to K --> 3 pi decays. In particular, we
extend the non-relativistic framework developed recently to include real and
virtual photons and show that, in a well-defined power counting scheme, the
results reproduce corrections obtained in the relativistic calculation. Real
photons are included exactly, beyond the soft-photon approximation, and we
compare the result with the latter. The singularities generated by pionium near
threshold are investigated, and a region is identified where standard
perturbation theory in the fine structure constant alpha may be applied. We
expect that the formulae provided allow one to extract S-wave pi pi scattering
lengths from the cusp effect in these decays with high precision.


title:
Irreducibility of the Hilbert-Blumenthal moduli spaces with parahoric
  level structure

abstract:
  We determine the number of irreducible components of the reduction mod p of
any Hilbert-Blumenthal moduli space with a parahoric level structure, where p
is unramified in the totally real field.


title: Modeling belief systems with scale-free networks

abstract:
  Evolution of belief systems has always been in focus of cognitive research.
In this paper we delineate a new model describing belief systems as a network
of statements considered true. Testing the model a small number of parameters
enabled us to reproduce a variety of well-known mechanisms ranging from opinion
changes to development of psychological problems. The self-organizing opinion
structure showed a scale-free degree distribution. The novelty of our work lies
in applying a convenient set of definitions allowing us to depict opinion
network dynamics in a highly favorable way, which resulted in a scale-free
belief network. As an additional benefit, we listed several conjectural
consequences in a number of areas related to thinking and reasoning.


title: Imaging X-ray sources at a finite distance in coded mask instruments

abstract:
  We present a method we developed for the correction of the beam divergence in
finite distance sources imaging through coded mask instruments. We discuss the
defocusing artifacts induced by the finite distance showing two different
approaches to remove such spurious effects. We applied our method to
one-dimensional coded-mask systems, although it is also applicable to 2D
systems as well. We provide a detailed mathematical description of the adopted
method and of the systematics introduced in the reconstructed image (e. g. the
fraction of source flux collected in the reconstructed peak counts). The
accuracy of this method was tested by simulating point-like and extended
sources at finite distance with the instrumental set-up of the SuperAGILE
experiment, the one dimensional coded-mask X-ray imager on-board the AGILE
mission. We obtained reconstructed images of good quality and high source
location accuracy. Finally, we show the results obtained by applying this
method to real data collected during the calibration campaign of SuperAGILE.
Our method was demonstrated to be a powerful tool to investigate the imaging
response of the experiment, particularly, the absorption due to the materials
intercepting the line of sight of the instrument and the conversion between
detector pixel and sky direction.


title: Singular solutions to the Loewner equation

abstract:
  We consider the L\"owner differential equation generating univalent self-maps
of the unit disk (or of the upper half-plane). If the solution to this equation
represents a one-slit map, then the driving term is a continuous function. The
reverse statement is not true in general as a famous Kufarev's example shows.
We address the following main problem: to find a criterium for the L\"owner
equation to generate one-slit solutions. New examples of non-slit solutions to
the L\"owner equation are presented. Properties of singular slit solutions are
revealed.


title: Subtraction method of computing QCD jet cross sections at NNLO accuracy

abstract:
  We present a general subtraction method for computing radiative corrections
to QCD jet cross sections at next-to-next-to-leading order accuracy. The steps
needed to set up this subtraction scheme are the same as those used in
next-to-leading order computations. However, all steps need non-trivial
modifications, which we implement such that that those can be defined at any
order in perturbation theory. We give a status report of the implementation of
the method to computing jet cross sections in electron-positron annihilation at
the next-to-next-to-leading order accuracy.


title:
Synchronization interfaces and overlapping communities in complex
  networks

abstract:
  We show that a complex network of phase oscillators may display interfaces
between domains (clusters) of synchronized oscillations. The emergence and
dynamics of these interfaces are studied in the general framework of
interacting phase oscillators composed of either dynamical domains (influenced
by different forcing processes), or structural domains (modular networks). The
obtained results allow to give a functional definition of overlapping
structures in modular networks, and suggest a practical method to identify
them. As a result, our algorithm could detect information on both single
overlapping nodes and overlapping clusters.


title: Exact distribution of the maximal height of p vicious walkers

abstract:
  Using path integral techniques, we compute exactly the distribution of the
maximal height H_p of p nonintersecting Brownian walkers over a unit time
interval in one dimension, both for excursions (p-watermelons with a wall) and
bridges (p-watermelons without a wall), for all integer p\ge 1. For large p, we
show that < H_p > \sim \sqrt{2p} (excursions) whereas < H_p > \sim \sqrt{p}
(bridges). Our exact results prove that previous numerical experiments only
measured the pre-asymptotic behaviors and not the correct asymptotic ones. In
addition, our method establishes a physical connection between vicious walkers
and random matrix theory.

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


title: Optical Activity of Planar Achiral Metamaterials

abstract:
  We report that the classical phenomena of optical activity and circular
dichroism, which are traditionally associated with chirality (helicity) of
organic molecules, proteins and inorganic structures, can be observed in
non-chiral artificial media. Intriguingly, our metamaterial structure yields
exceptionally strong resonant optical activity, which also leads to the
appearance of a backward wave, a characteristic sign of negative-index media.


title: Coupled-channel effects in the pp -> ppK+K- reaction

abstract:
  The cross sections for the pp -> ppK+K- reaction were measured at three beam
energies 2.65, 2.70, and 2.83 GeV at the COSY-ANKE facility. The shape of the
K+K- spectrum at low invariant masses largely reflects the importance of
K\bar{K} final state interactions. It is shown that these data can be
understood in terms of an elastic K+K- rescattering plus a contribution coming
from the production of a K0\bar{K}0 pair followed by a charge-exchange
rescattering. Though the data are not yet sufficient to establish the size of
the cusp at the K0\bar{K}0 threshold, the low mass behaviour suggests that
isospin-zero production is dominant.


title:
Collinear improvement of the BFKL kernel in the electroproduction of two
  light vector mesons

abstract:
  We test the performance of a RG-improved kernel in the determination of the
amplitude of a physical process, the electroproduction of two light vector
mesons,in the BFKL approach at the next-to-leading approximation (NLA). We find
that a smooth behavior of the amplitude with the center-of-mass energy can be
achieved, setting the renormalization and energy scales appearing in the
subleading terms to values much closer to the kinematical scales of the process
than in approaches based on unimproved kernels.


title:
Superconducting parallel nanowire detector with photon number resolving
  functionality

abstract:
  We present a new photon number resolving detector (PNR), the Parallel
Nanowire Detector (PND), which uses spatial multiplexing on a subwavelength
scale to provide a single electrical output proportional to the photon number.
The basic structure of the PND is the parallel connection of several NbN
superconducting nanowires (100 nm-wide, few nm-thick), folded in a meander
pattern. Electrical and optical equivalents of the device were developed in
order to gain insight on its working principle. PNDs were fabricated on 3-4 nm
thick NbN films grown on sapphire (substrate temperature TS=900C) or MgO
(TS=400C) substrates by reactive magnetron sputtering in an Ar/N2 gas mixture.
The device performance was characterized in terms of speed and sensitivity. The
photoresponse shows a full width at half maximum (FWHM) as low as 660ps. PNDs
showed counting performance at 80 MHz repetition rate. Building the histograms
of the photoresponse peak, no multiplication noise buildup is observable and a
one photon quantum efficiency can be estimated to be QE=3% (at 700 nm
wavelength and 4.2 K temperature). The PND significantly outperforms existing
PNR detectors in terms of simplicity, sensitivity, speed, and multiplication
noise.


title: Identifying Transiting Circumbinary Planets

abstract:
  Transiting planets manifest themselves by a periodic dimming of their host
star by a fixed amount. On the other hand, light curves of transiting
circumbinary (CB) planets are expected to be neither periodic nor to have a
single depth while in transit, making BLS [Kovacs et al. 2002] almost
ineffective. Therefore, a modified version for the identification of CB planets
was developed - CB-BLS. We show that using CB-BLS it is possible to find CB
planets in the residuals of light curves of eclipsing binaries (EBs) that have
noise levels of 1% or more. Using CB-BLS will allow to easily harness the
massive ground- and space- based photometric surveys to look for these objects.
Detecting transiting CB planets is expected to have a wide range of
implications, for e.g.: The frequency of CB planets depend on the planetary
formation mechanism - and planets in close pairs of stars provides a most
restrictive constraint on planet formation models. Furthermore, understanding
very high precision light curves is limited by stellar parameters - and since
for EBs the stellar parameters are much better determined, the resultant
planetary structure models will have significantly smaller error bars, maybe
even small enough to challenge theory.


title:
Asymptotic analysis for bifurcating autoregressive processes via a
  martingale approach

abstract:
  We study the asymptotic behavior of the least squares estimators of the
unknown parameters of bifurcating autoregressive processes. Under very weak
assumptions on the driven noise of the process, namely conditional pair-wise
independence and suitable moment conditions, we establish the almost sure
convergence of our estimators together with the quadratic strong law and the
central limit theorem. All our analysis relies on non-standard asymptotic
results for martingales.


title: The sequence of ideas in a re-discovery of the Colombeau algebras

abstract:
  This is a gentle introduction to Colombeau nonlinear generalized functions, a
generalization of the concept of distributions such that distributions can
freely be multiplied. It is intended to physicists and applied mathematicians
who prefer a `step-by-step approach' to a `top-down indoctrination.'
  No particular prerequisite knowledge is necessary -- and in less than one
hour you should know everything you need to know and were afraid to ask about
Colombeau algebras and their applications in physics...
  A selected bibliography is appended, giving examples of applications to
partial differential and wave equations, electrodynamics, hydrodynamics,
general relativity, and quantum field theory.


title: Recent results on the properties of two-phase argon avalanche detectors

abstract:
  The characteristic properties of two-phase Ar avalanche detectors, including
those obtained with CsI photocathode, are further studied. Such detectors are
relevant in the field of coherent neutrino-nucleus scattering and dark matter
search experiments. The detectors investigated comprised a 1 cm thick liquid Ar
layer followed by a triple-GEM multiplier. In these detectors, typical gains
reaching 10000 were obtained with good reproducibility and a stable operation
for at least one day was demonstrated. Amplitude and pulse-shape
characteristics are presented under irradiation with X-rays, gamma-rays and
neutrons from different radioactive sources. The detection of both primary
scintillation and ionization signals at higher gains, at a deposited energy of
60 keV, has been demonstrated.


title: From multileg loops to trees (by-passing Feynman's Tree Theorem)

abstract:
  We illustrate a duality relation between one-loop integrals and single-cut
phase-space integrals. The duality relation is realised by a modification of
the customary +i0 prescription of the Feynman propagators. The new prescription
regularizing the propagators, which we write in a Lorentz covariant form,
compensates for the absence of multiple-cut contributions that appear in the
Feynman Tree Theorem. The duality relation can be extended to generic one-loop
quantities, such as Green's functions, in any relativistic, local and unitary
field theories.


title: The star formation in the L1615/L1616 cometary cloud

abstract:
  The present work aims at performing a comprehensive census and
characterisation of the pre-main sequence (PMS) population in the cometary
cloud L1615/L1616, in order to assess the significance of the triggered star
formation scenario and investigate the impact of massive stars on its star
formation history and mass spectrum. Our study is based on UBVRcIc and JHKs
photometry, as well as optical multi-object spectroscopy. We performed a
physical parametrisation of the young stellar population in L1615/L1616. We
identified 25 new T Tauri stars mainly projected on the dense head of the
cometary cloud, almost doubling the current number of known members. We studied
the spatial distribution of the cloud members as a function of the age and
H$\alpha$ emission. The star formation efficiency in the cloud is about 7-8 %,
as expected for molecular clouds in the vicinity of OB associations. The slope
of the initial mass function (IMF), in the mass range 0.1<M<5.5 $M_{\odot}$, is
consistent with that of other T and OB associations, providing further support
of an universal IMF down to the hydrogen burning limit, regardless of
environmental conditions. The cometary appearance, as well as the high star
formation efficiency, can be explained in terms of triggered star formation
induced by the strong UV radiation from OB stars or supernovae shockwaves. The
age spread as well as both the spatial and age distribution of the PMS objects
provide strong evidence of sequential, multiple events and possibly still
ongoing star formation activity in the cloud.


title: Symmetry Reduction of Lane-Emden Equation for Polytropes

abstract:
  We describe an ansatz for symmetry reduction of the Lane-Emden equation for
an arbitrary polytropic index n, admitting only one symmetry generator. For the
reduced first order differential equation it is found that standard reduction
procedure do not admit any non-trivial Lie point symmetry. However some special
solutions for the differential equation are obtained.


title:
An extensive photometric study of the Blazhko RR Lyrae star MW Lyr: I.
  Light curve solution

abstract:
  We have obtained the most extensive and most accurate photometric data of a
Blazhko variable MW Lyr during the 2006-2007 observing seasons. The data within
each 0.05 phase bin of the modulation period (P_m=1/f_m) cover the entire light
cycle of the primary pulsation period (P_0=1/f_0), making possible a very
rigorous and complete analysis. The modulation period is found to be 16.5462 d,
which is about half of that was reported earlier from visual observations.
Previously unknown features of the modulation have been detected. Besides the
main modulation frequency f_m, sidelobe modulation frequencies around the
pulsation frequency and its harmonics appear at +/- 2 f_m, +/- 4 f_m, and +/-
12.5 f_m separations as well. Residual signals in the prewhitened light curve
larger than the observational noise appear at the minimum-rising branch-maximum
phase of the pulsation, which most probably arise from some stochastic/chaotic
behaviour of the pulsation/modulation. The Fourier parameters of the mean light
curve differ significantly from the averages of the Fourier parameters of the
observed light curves in the different phases of the Blazhko cycle.
Consequently, the mean light curve of MW Lyrae never matches its actual light
variation. The Phi_21, Phi_31 phase differences in different phases of the
modulation show unexpected stability during the Blazhko cycle. A new
phenomenological description of the light curve variation is defined that
separates the amplitude and phase (period) modulations utilising the phase
coherency of the lower order Fourier phases.


title:
Measuring Baryon Acoustic Oscillations along the line of sight with
  photometric redshifs: the PAU survey

abstract:
  Baryon Acoustic Oscillations (BAO) provide a standard ruler of known physical
length, making it a promising probe of the nature of dark energy. The detection
of BAO requires measuring galaxy positions and redshifts. "Transversal"
(angular distance) BAO measure the angular size of this scale, while
"line-of-sight" (or "radial") BAO require precise redshifts, but provide a
direct measurement of the Hubble parameter at different redshifts, a more
sensitive probe of dark energy. The main goal of this paper is to show that a
precision of sigma_z ~0.003(1 + z) is sufficient to measure BAO in the radial
direction. This precision can be achieved for bright, red galaxies, by using a
filter system comprising about 40 filters, each with a width of ~100 A, from ~
4000 A to ~ 8000 A, supplemented by two broad-band filters. We describe a
practical implementation, a new galaxy survey, PAU, to be carried out with a
telescope/camera combination with an etendue of about 20 m^2deg^2, and covering
8000 sq. deg. in the sky in four years. We expect to measure positions and
redshifts for over 14 million red, early-type galaxies with L > L* and i_AB <
22.5 in the interval 0.1 < z < 0.9, with sigma_z < 0.003(1 + z). This
population has a number density n > 10^-3 Mpc^-3 h^3 within the 9 (Gpc/h)^3
volume of the survey, ensuring that the error in the determination of the BAO
scale is not limited by shot-noise. By itself, such a survey will deliver
precisions of order 5% in the dark-energy equation of state parameter w, if
assumed constant, and can determine its time derivative when combined with
future CMB measurements. In addition, PAU will yield high-quality redshift and
low-resolution spectroscopy for hundreds of millions of other galaxies.


title:
Dependence of the decoherence of polarization states in phase-damping
  channels on the frequency spectrum envelope of photons

abstract:
  We consider the decoherence of photons suffering in phase-damping channels.
By exploring the evolutions of single-photon polarization states and two-photon
polarization-entangled states, we find that different frequency spectrum
envelopes of photons induce different decoherence processes. A white frequency
spectrum can lead the decoherence to an ideal Markovian process. Some color
frequency spectrums can induce asymptotical decoherence, while, some other
color frequency spectrums can make coherence vanish periodically with variable
revival amplitudes. These behaviors result from the non-Markovian effects on
the decoherence process, which may give rise to a revival of coherence after
complete decoherence.


title: Ikehara-type theorem involving boundedness

abstract:
  Consider any Dirichlet series sum a_n/n^z with nonnegative coefficients a_n
and finite sum function f(z)=f(x+iy) when x is greater than 1. Denoting the
partial sum a_1+...+a_N by s_N, the paper gives the following necessary and
sufficient condition in order that (s_N)/N remain bounded as N goes to
infinity. For x tending to 1 from above, the quotient q(x+iy)=f(x+iy)/(x+iy)
must converge to a pseudomeasure q(1+iy), the distributional Fourier transform
of a bounded function. The paper also gives an optimal estimate for (s_N)/N
under the "real condition" that (1-x)f(x) remain bounded as x tends to 1 from
above.


title: Discrete Skyrmions in 2+1 and 3+1 Dimensions

abstract:
  This paper describes a lattice version of the Skyrme model in 2+1 and 3+1
dimensions. The discrete model is derived from a consistent discretization of
the radial continuum problem. Subsequently, the existence and stability of the
skyrmion solutions existing on the lattice are investigated. One consequence of
the proposed models is that the corresponding discrete skyrmions have a high
degree of stability, similar to their continuum counterparts.


title: Long Gamma-Ray Bursts and the Morphology of their Host Galaxies

abstract:
  We present the results of population syntheses for binary stars carried out
using the ``Scenario Machine'' code with the aim of analyzing events that may
result in long gamma-ray bursts. We show that the observed distribution of
morphological types of the host galaxies of long gamma-ray bursts can be
explained in a model in which long gamma-ray bursts result from the core
collapse of massive Wolf-Rayet stars in close binaries. The dependence of the
burst rate on galaxy type is associated with an increase in the rate of
stellar-wind mass-loss with increasing stellar metallicity. The separation of
binary components at the end of their evolution increases with the stellar-wind
rate, resulting in a reduction of the number of binaries that produce
gamma-bursts.


title: On exponentials of exponential generating series

abstract:
  Identifying the algebra of exponential generating series with the shuffle
algebra of formal power series, one can define an exponential map
${\mathop{exp}}_!:X\mathbb K[[X]]\longrightarrow 1+X\mathbb K[[X]]$ for the
associated Lie group formed by exponential generating series with constant
coefficient 1 over an arbitrary field $\mathbb K$. The main result of this
paper states that the map ${\mathop{exp}}_!$ (and its inverse map
${\mathop{log}}_!$) induces a bijection between rational, respectively
algebraic, series in $X\mathbb K [[X]]$ and $1+X\mathbb K[[X]]$ if the field
$\mathbb K$ is a subfield of the algebraically closed field $\bar{\mathbb F}_p$
of characteristic $p$.


title: Mixing and Decoherence to Nearest Separable States

abstract:
  We consider a class of entangled states of a quantum system (S) and a second
system (A) where pure states of the former are correlated with mixed states of
the latter, and work out the entanglement measure with reference to the nearest
separable state. Such `pure-mixed' entanglement is expected when the system S
interacts with a macroscopic measuring apparatus in a quantum measurement,
where the quantum correlation is destroyed in the process of
environment-induced decoherence whereafter only the classical correlation
between S and A remains, the latter being large compared to the former. We
present numerical evidence that the entangled S-A state drifts towards the
nearest separable state through decoherence, with an additional tendency of
equimixing among relevant groups of apparatus states.


title: Combustion dynamics in steady compressible flows

abstract:
  We study the evolution of a reactive field advected by a one-dimensional
compressible velocity field and subject to an ignition-type nonlinearity. In
the limit of small molecular diffusivity the problem can be described by a
spatially discretized system, and this allows for an efficient numerical
simulation. If the initial field profile is supported in a region of size l <
lc one has quenching, i.e., flame extinction, where lc is a characteristic
length-scale depending on the system parameters (reacting time, molecular
diffusivity and velocity field). We derive an expression for lc in terms of
these parameters and relate our results to those obtained by other authors for
different flow settings.


title: Effect of a positive cosmological constant on cosmic strings

abstract:
  We study cosmic Nielsen-Olesen strings in space-times with a positive
cosmological constant. For the free cosmic string in a cylindrically symmetric
space-time, we calculate the contribution of the cosmological constant to the
angle deficit, and to the bending of null geodesics. For a cosmic string in a
Schwarzschild-de Sitter space-time, we use Kruskal patches around the inner and
outer horizons to show that a thin string can pierce them.


title:
Comparing the first and second order theories of relativistic
  dissipative fluid dynamics using the 1+1 dimensional relativistic flux
  corrected transport algorithm

abstract:
  Focusing on the numerical aspects and accuracy we study a class of bulk
viscosity driven expansion scenarios using the relativistic Navier-Stokes and
truncated Israel-Stewart form of the equations of relativistic dissipative
fluids in 1+1 dimensions. The numerical calculations of conservation and
transport equations are performed using the numerical framework of flux
corrected transport. We show that the results of the Israel-Stewart causal
fluid dynamics are numerically much more stable and smoother than the results
of the standard relativistic Navier-Stokes equations.


title: T-odd Effects in Photon-Jet Production at the Tevatron

abstract:
  The angular distribution in photon-jet production in p\bar{p} -> \gamma jet X
is studied within a generalized factorization scheme taking into account the
transverse momentum of the partons in the initial hadrons. Within this scheme
an anomalously large cos(2\phi) asymmetry observed in the Drell-Yan process
could be attributed to the T-odd, spin and transverse momentum dependent parton
distribution function h_1^{\perp q}(x, p_{\perp}^2). The same function is
expected to produce a cos(2\phi) asymmetry in the photon-jet production cross
section. This particular azimuthal asymmetry is estimated to be smaller than
the Drell-Yan asymmetry but still of considerable size for Tevatron kinematics,
offering a new possibility to study T-odd effects at the Tevatron.


title:
Evidence for orthorhombic distortions in the ordered state of
  ZnCr$_2$O$_4$: A magnetic resonance study

abstract:
  We present an elaborate electron-spin resonance study of the low-energy
dynamics and magnetization in the ordered phase of the magnetically frustrated
spinel ZnCr$_2$O$_4$. We observe several resonance modes corresponding to
different structural domains and found that the number of domains can be easily
reduced by field-cooling the sample through the transition point. To describe
the observed antiferromagnetic resonance spectra it is necessary to take into
account an orthorhombic lattice distortion in addition to the earlier reported
tetragonal distortion which both appear at the antiferromagnetic phase
transition.


title: Coulomb Parameter U and Correlation Strength in LaFeAsO

abstract:
  First principles constrained density functional theory scheme in Wannier
functions formalism has been used to calculate Coulomb repulsion U and Hund's
exchange J parameters for iron 3d electrons in LaFeAsO. Results strongly depend
on the basis set used in calculations: when O-2p, As-4p, and Fe-3d orbitals and
corresponding bands are included, computation results in U=3-4 eV, however,
with the basis set restricted to Fe-3d orbitals and bands only, computation
gives parameters corresponding to F^0=0.8 eV, J=0.5 eV. LDA+DMFT (the Local
Density Approximation combined with the Dynamical Mean-Field Theory)
calculation with this parameters results in weakly correlated electronic
structure that is in agreement with X-ray experimental spectra.


title: High Precision Gauge Boson Pair Production at the LHC

abstract:
  We discuss the recent derivation of the two loop virtual QCD corrections to
the W boson pair production in the quark-anti-quark-annihilation channel in the
limit where all kinematical invariants are large compared to the mass of the W
boson. In particular, we describe the use of the PSLQ algorithm on an example
integral.


title:
Solution of large linear systems with embedded network structure for a
  non-homogeneous network flow programming problem

abstract:
  In the paper we consider the linear underdetermined system of a special type.
Systems of this type appear in non-homogeneous network flow programming
problems in the form of systems of constraints and can be characterized as
systems with a large sparse submatrix representing the embedded network
structure. We develop a direct method for finding solutions of the system. The
algorithm is based on the theoretic-graph specificities for the structure of
the support and properties of the basis of a solution space of a homogeneous
system. One of the key steps is decomposition of the system. A simple example
is regarded at the end of the paper.


title:
Pressure-energy correlations in liquids. I. Results from computer
  simulations

abstract:
  We show that a number of model liquids at fixed volume exhibit strong
correlations between equilibrium fluctuations of the configurational parts of
(instantaneous) pressure and energy. We present detailed results for thirteen
systems, showing in which systems these correlations are significant. These
include Lennard-Jones liquids (both single- and two-component) and several
other simple liquids, but not hydrogen-bonding liquids like methanol and water,
nor the Dzugutov liquid which has significant contributions to pressure at the
second nearest neighbor distance. The pressure-energy correlations, which for
the Lennard-Jones case are shown to also be present in the crystal and glass
phases, reflect an effective inverse power-law potential dominating
fluctuations, even at zero and slightly negative pressure. An exception to the
inverse-power law explanation is a liquid with hard-sphere repulsion and a
square-well attractive part, where a strong correlation is observed, but only
after time-averaging. The companion paper [arXiv:0807.0551] gives a thorough
analysis of the correlations, with a focus on the Lennard-Jones liquid, and a
discussion of some experimental and theoretical consequences.


title: Pressure-energy correlations in liquids. II. Analysis and consequences

abstract:
  We present an analysis and discuss consequences of the strong correlations of
the configurational parts of pressure and energy in their equilibrium
fluctuations at fixed volume reported for simulations of several liquids in the
companion paper [arXiv:0807.0550]. The analysis concentrates specifically on
the single-component Lennard-Jones system. We demonstrate that the potential
may be replaced, at fixed volume, by an effective power-law, but not because
only short distance encounters dominate the fluctuations. Indeed, contributions
to the fluctuations are associated with the whole first peak of the RDF, as we
demonstrate by an analysis of the spatially resolved covariance matrix. The
reason the effective power-law works so well depends on going beyond
single-pair effects and on the constraint of fixed volume. In particular, a
better approximation to the potential includes a linear term, which contributes
to the mean values of potential energy and virial, but not to their
fluctuations. We also study the T=0 limit of the crystalline phase, where the
correlation coefficient becomes very close, but not equal, to unity. We then
consider four consequences of strong pressure-energy correlations: (1)
analyzing experimental data for supercritical Ar we find 96% correlation; (2)
we discuss the significance acquired by the correlations for viscous van der
Waals liquids approaching the glass transition: For strongly correlating
viscous liquids knowledge of just one of the eight frequency-dependent
thermoviscoelastic response functions basically implies knowledge of them all;
(3) we re-interpret aging simulations of ortho-terphenyl carried out by Mossa
{\it et al.} in 2002, showing their conclusions follow from the strongly
correlating property; and (4) we discuss correlations in model biomembranes.


title: Decomposition of Multiple Coverings into More Parts

abstract:
  We prove that for every centrally symmetric convex polygon Q, there exists a
constant alpha such that any alpha*k-fold covering of the plane by translates
of Q can be decomposed into k coverings. This improves on a quadratic upper
bound proved by Pach and Toth (SoCG'07). The question is motivated by a sensor
network problem, in which a region has to be monitored by sensors with limited
battery lifetime.


title:
An extremely wide and very low-mass pair with common proper motion. Is
  it representative of a nearby halo stream?

abstract:
  (abridged) We describe the discovery of an extremely wide pair of low-mass
stars with a common large proper motion and discuss their possible membership
in a Galactic halo stream crossing the Solar neighbourhood. (...) The late-type
(M7) dwarf SSSPM J2003$-$4433 and the ultracool subdwarf SSSPM J1930$-$4311
(sdM7) sharing the same very large proper motion of about 860 mas/yr were found
in the same sky region with an angular separation of about 6\degr. From the
comparison with other high proper motion catalogues we have estimated the
probability of a chance alignment of the two new large proper motions to be
less than 0.3%. From the individually estimated spectroscopic distances of
about $38^{+10}_{-7}$ pc and $72^{+21}_{-16}$ pc, respectively for the M7 dwarf
and the sdM7 subdwarf, and in view of the accurate agreement in their large
proper motions we assume a common distance of about 50 pc and a projected
physical separation of about 5 pc. The mean heliocentric space velocity of the
pair $(U,V,W)=(-232, -170, +74)$ km/s, based on the correctness of the
preliminary radial velocity measurement for only one of the components and on
the assumption of a common distance and velocity vector, is typical of the
Galactic halo population. The large separation and the different metallicities
of dwarfs and subdwarfs make a common formation scenario as a wide binary
(later disrupted) improbable, although there remains some uncertainty in the
spectroscopic classification scheme of ultracool dwarfs/subdwarfs so that a
dissolved binary origin cannot be fully ruled out yet. It seems more likely
that this wide pair is part of an old halo stream. (...)


title: A new family of Markov branching trees: the alpha-gamma model

abstract:
  We introduce a simple tree growth process that gives rise to a new
two-parameter family of discrete fragmentation trees that extends Ford's alpha
model to multifurcating trees and includes the trees obtained by uniform
sampling from Duquesne and Le Gall's stable continuum random tree. We call
these new trees the alpha-gamma trees. In this paper, we obtain their splitting
rules, dislocation measures both in ranked order and in sized-biased order, and
we study their limiting behaviour.


title: Color evolution of 2 -> 3 processes

abstract:
  The color structure needed for resummation of all colored 2 -> 3 processes is
calculated using multiplet inspired s-channel bases. In this way the resulting
matrices, describing the color structure, are guaranteed to obey simplifying
symmetries.


title:
Lattice study of vacuum polarization function and determination of
  strong coupling constant

abstract:
  We calculate the vacuum polarization functions on the lattice using the
overlap fermion formulation.By matching the lattice data at large momentum
scales with the perturbative expansion supplemented by Operator Product
Expansion (OPE), we extract the strong coupling constant $\alpha_s(\mu)$ in
two-flavor QCD as $\Lambda^{(2)}_{\overline{MS}}$ = $0.234(9)(^{+16}_{- 0})$
GeV, where the errors are statistical and systematic, respectively. In
addition, from the analysis of the difference between the vector and
axial-vector channels, we obtain some of the four-quark condensates.


title: CP violation and gravity as the weakest force

abstract:
  We argue that CP violation has rather dramatic impact on the "gravity as the
weakest force" conjecture. Namely we find that new ultraviolet scale must be
$\Lambda \lesssim \theta g^3 M_P$, where $\theta$ is an effective parameter
describing CP violation and $g$ is the gauge coupling constant. The bound
implies that CP-conserving limit is discontinuous, and possibly indicates that
the class of effective theories with strict CP conservation is inconsistent
with a fundamental theory incorporating quantum gravity. At the same time, the
mass hierarchy problem can be explained due to the smallness of the CP
violation, $\theta \sim 10^{-15}$ or so.


title: Sampling constraints in average: The example of Hugoniot curves

abstract:
  We present a method for sampling microscopic configurations of a physical
system distributed according to a canonical (Boltzmann-Gibbs) measure, with a
constraint holding in average. Assuming that the constraint can be controlled
by the volume and/or the temperature of the system, and considering the control
parameter as a dynamical variable, a sampling strategy based on a nonlinear
stochastic process is proposed. Convergence results for this dynamics are
proved using entropy estimates.As an application, we consider the computation
of points along the Hugoniot curve, which are equilibrium states obtained after
equilibration of a material heated and compressed by a shock wave.


title: Weakly Renormalized Near 1/16 SUSY Fermi Liquid Operators in N = 4 SYM

abstract:
  We discuss a class of Fermi Liquid Operators in N = 4 SYM. We show that these
operators are eigenstates of the full quantum dilatation operator. We compute
their 1 and 2 loop anomalous dimensions, and show that, similar to Fermi
liquids in condensed matter systems, these corrections are suppressed by an
arbitrarily small parameter, which is the equivalent of one over the Fermi
energy. These operators are, at the classical level, descendants of 1/16 BPS
operators, with some scaling properties similar to those of the 1/16 Black
Holes in AdS_5.


title: On the symmetry of b-functions of linear free divisors

abstract:
  We introduce the concept of a prehomogeneous determinant as a nonreduced
version of a linear free divisor. Both are special cases of prehomogeneous
vector spaces. We show that the roots of the $b$-function are symmetric about
-1 for reductive prehomogeneous determinants and for regular special linear
free divisors. For general prehomogeneous determinants, we describe conditions
under which this symmetry still holds. Combined with Kashiwara's theorem on the
roots of b-functions, our symmetry result shows that -1 is the only integer
root of the b-function. This gives a positive answer to a problem posed by
Castro-Jimenez and Ucha-Enriquez in the above cases. We study the condition of
(strong) Euler homogeneity in terms of the action of the stabilizers on the
normal spaces. As an application of our results, we show that the logarithmic
comparison theorem holds for Koszul free reductive linear free divisors exactly
if they are (strongly) Euler homogeneous.


title:
Tuning the interlayer spacing in high T_c superconductors: penetration
  depth and two-dimensional superfluid density

abstract:
  Substantial control of the interlayer spacing in Bi-based high temperature
superconductors has been achieved through the intercalation of guest molecules
between the superconducting layers. Measurements using implanted muons reveal
that the penetration depth increases with increasing layer separation while T_c
does not vary appreciably, demonstrating that the bulk superfluid density is
not the determining factor controlling T_c. Our results strongly suggest that
the superfluid density appearing in the Uemura scaling relation n_s/m* \propto
T_c should be interpreted as the two dimensional density within the
superconducting layers, which we find to be constant for each class of system
investigated.


title: Kondo effect and channel mixing in oscillating molecules

abstract:
  We investigate the electronic transport through a molecule in the Kondo
regime. The tunneling between the electrode and the molecule is asymmetrically
modulated by the oscillations of the molecule, i.e., if the molecule gets
closer to one of the electrodes the tunneling to that electrode will increase
while for the other electrode it will decrease. The system is described by a
two-channel Anderson model with phonon-assisted hybridization, which is solved
with the Wilson numerical renormalization group method. The results for several
functional forms of tunneling modulation are presented. For a linearized
modulation the Kondo screening of the molecular spin is caused by the even or
odd conduction channel. At the critical value of the electron-phonon coupling
an unstable two-channel Kondo fixed point is found. For a realistic modulation
the spin at the molecular orbital is Kondo screened by the even conduction
channel even in the regime of strong coupling. A universal consequence of the
electron-phonon coupling is the softening of the phonon mode and the related
instability to perturbations that break the left-right symmetry. When the
frequency of oscillations decreases below the magnitude of such perturbation,
the molecule is abruptly attracted to one of the electrodes. In this regime,
the Kondo temperature is enhanced and, simultaneously, the conductance through
the molecule is suppressed.


title:
The exponentially truncated q-distribution: A generalized distribution
  for real complex systems

abstract:
  To know the statistical distribution of a variable is an important problem in
management of resources. Distributions of the power law type are observed in
many real systems. However power law distributions have an infinite variance
and thus can not be used as a standard distribution. Normally professionals in
the area use normal distribution with variable parameters or some other
approximate distribution like Gumbel, Wakeby, or Pareto, which has limited
validity.
  Tsallis presented a microscopic theory of power law in the framework of
non-extensive thermodynamics considering long-range interactions or long
memory. In the present work, we consider softing of long-range interactions or
memory and presented a generalized distribution which have finite variance and
can be used as a standard distribution for all real complex systems with power
law behaviour. We applied this distribution for a financial system, rain
precipitation and some geophysical and social systems. We found a good
agreement for entire range in all cases for the probability density function
(pdf) as well as the accumulated probability. This distribution shows universal
nature of the size limiting in real systems.


title: Linear-Programming Receivers

abstract:
  It is shown that any communication system which admits a sum-product (SP)
receiver also admits a corresponding linear-programming (LP) receiver. The two
receivers have a relationship defined by the local structure of the underlying
graphical model, and are inhibited by the same phenomenon, which we call
'pseudoconfigurations'. This concept is a generalization of the concept of
'pseudocodewords' for linear codes. It is proved that the LP receiver has the
'optimum certificate' property, and that the receiver output is the lowest cost
pseudoconfiguration. Equivalence of graph-cover pseudoconfigurations and
linear-programming pseudoconfigurations is also proved. While the LP receiver
is generally more complex than the corresponding SP receiver, the LP receiver
and its associated pseudoconfiguration structure provide an analytic tool for
the analysis of SP receivers. As an example application, we show how the LP
design technique may be applied to the problem of joint equalization and
decoding.


title: Music, Complexity, Information

abstract:
  These are the preparatory notes for a Science & Music essay, "Playing by
numbers", appeared in Nature 453 (2008) 988-989.


title: Finite-size effects of Membranes on AdS_4 x S_7

abstract:
  We consider semi-classical solution of membranes on the AdS_4 x S^7. This is
supposed to be dual to the N=6 super Chern-Simons theory with k=1 in a planar
limit recently proposed by Aharony, Bergmann, Jafferis, and Maldacena (ABJM).
We have identified giant magnon and single spike states on the membrane by
reducing them to the Neumamm - Rosochatius integrable system. We also connect
these to the complex sine-Gordon integrable model. Based on this approach, we
find finite-size membrane solutions and obtain their images in the complex
sine-Gordon system along with the leading finite-size corrections to the
energy-charge relations.


title:
Towards all-order Laurent expansion of generalized hypergeometric
  functions around rational values of parameters

abstract:
  We prove the following theorems:
  1) The Laurent expansions in epsilon of the Gauss hypergeometric functions
  2F1(I_1+a*epsilon, I_2+b*epsilon; I_3+p/q + c epsilon; z),
  2F1(I_1+p/q+a*epsilon, I_2+p/q+b*epsilon; I_3+ p/q+c*epsilon;z),
  2F1(I_1+p/q+a*epsilon, I_2+b*epsilon; I_3+p/q+c*epsilon;z), where
I_1,I_2,I_3,p,q are arbitrary integers, a,b,c are arbitrary numbers and epsilon
is an infinitesimal parameter, are expressible in terms of multiple
polylogarithms of q-roots of unity with coefficients that are ratios of
polynomials; 2) The Laurent expansion of the Gauss hypergeometric function
2F1(I_1+p/q+a*epsilon, I_2+b*epsilon; I_3+c*epsilon;z) is expressible in terms
of multiple polylogarithms of q-roots of unity times powers of logarithm with
coefficients that are ratios of polynomials; 3) The multiple inverse rational
sums (see Eq. (2)) and the multiple rational sums (see Eq. (3)) are expressible
in terms of multiple polylogarithms; 4) The generalized hypergeometric
functions (see Eq. (4)) are expressible in terms of multiple polylogarithms
with coefficients that are ratios of polynomials.


title:
Differential Harnack Estimates for Time-dependent Heat Equations with
  Potentials

abstract:
  In this paper, we prove a differential Harnack inequality for positive
solutions of time-dependent heat equations with potentials. We also prove a
gradient estimate for the positive solution of the time-dependent heat
equation.


title: Supersymmetry of the magnetic vortex

abstract:
  The N=2 supersymmetry of the Pauli Hamiltonian in any static magnetic field
in the plane combines, for the magnetic vortex, with Jackiw's bosonic
$o(2)\times o(2,1)$ symmetry, into an $o(2)\times osp(1/2)$ dynamical
supersymmetry.


title: Basic quantum mechanics for three Dirac equations in a curved spacetime

abstract:
  We study the basic quantum mechanics for a fully general set of Dirac
matrices in a curved spacetime by extending Pauli's method. We further extend
this study to three versions of the Dirac equation: the standard
(Dirac-Fock-Weyl or DFW) equation, and two alternative versions, both of which
are based on the recently proposed linear tensor representations of the Dirac
field (TRD). We begin with the current conservation: we show that the latter
applies to any solution of the Dirac equation, iff the field of Dirac matrices
$\gamma ^\mu $ satisfies a specific PDE. This equation is always satisfied for
DFW with its restricted choice for the $\gamma ^\mu $ matrices. It similarly
restricts the choice of the $\gamma ^\mu $ matrices for TRD. However, this
restriction can be achieved. The frame dependence of a general Hamiltonian
operator is studied. We show that in any given reference frame with minor
restrictions on the spacetime metric, the axioms of quantum mechanics impose a
unique form for the Hilbert space scalar product. Finally, the condition for
the general Dirac Hamiltonian operator to be Hermitian is derived in a general
curved spacetime. For DFW, the validity of this hermiticity condition depends
on the choice of the $\gamma ^\mu $ matrices.