title:
Parametric downconversion with optimized spectral properties in
  nonlinear photonic crystals

abstract:
  We study the joint spectral properties of photon pairs generated by
spontaneous parametric down-conversion in a one-dimensional nonlinear photonic
crystal in a collinear, degenerate, type-II geometry. We show that the photonic
crystal properties may be exploited to compensate for material dispersion and
obtain photon pairs that are nearly factorable, in principle, for arbitrary
materials and spectral regions, limited by the ability to fabricate the
nonlinear crystal with the required periodic variation in the refractive
indices for the ordinary and extraordinary waves.


title: On Algebraic Shift Equivalence of Matrices over Polynomial Rings

abstract:
  The paper studies algebraic strong shift equivalence of matrices over
$n$-variable polynomial rings over a principal ideal domain $D$($n\leq 2$). It
is proved that in the case $n=1$, every non-zero matrix over $D[x]$ has a full
rank factorization and every non-nilpotent matrix over $D[x]$ is algebraically
strong shift equivalent to a nonsingular matrix. In the case $n=2$, an example
of non-nilpotent matrix over $\mathbb{R}[x,y,z]=\mathbb{R}[x][y,z]$, which can
not be algebraically shift equivalent to a nonsingular matrix, is given.


title: Quantum parallelism as a tool for ensemble spin dynamics calculations

abstract:
  Efficient simulations of quantum evolutions of spin-1/2 systems are relevant
for ensemble quantum computation as well as in typical NMR experiments. We
propose an efficient method to calculate the dynamics of an observable provided
that the initial excitation is "local". It resorts a single entangled pure
initial state built as a superposition, with random phases, of the pure
elements that compose the mixture. This ensures self-averaging of any
observable, drastically reducing the calculation time. The procedure is tested
for two representative systems: a spin star (cluster with random long range
interactions) and a spin ladder.


title:
Searching for Star Formation Outside Galaxies: Multiwavelength Analysis
  of the Intragroup Medium of HCG100

abstract:
  We used multiwavelength data (HI, FUV, NUV, R) to search for evidence of star
formation in the intragroup medium of the Hickson Compact Group 100. We find
that young star-forming regions are located in the intergalactic HI clouds of
the compact group which extend to over 130 kpc away from the main galaxies. A
tidal dwarf galaxy candidate is located in the densest region of the HI tail,
61 kpc from the brightest group member and its age is estimated to be only 3.3
Myr. Fifteen other intragroup HII regions and TDG candidates are detected in
the GALEX FUV image and within a field 10'x10' encompassing the HI tail. They
have ages <200 Myr, HI masses of 10^(9.2-10.4) Msun, 0.001< SFR <0.01 Msun
yr^-1, and stellar masses 10^4.3--10^6.5 Msun. The HI clouds to which many of
them are associated have column densities about one order of magnitude lower
than N(HI)~10^21 cm^-2.


title: Completions of quantum coordinate rings

abstract:
  Given an iterated skew polynomial ring C[y_1;t_1,d_1]ldots [y_n;t_n,d_n] over
a complete local ring C with maximal ideal m, we prove, under suitable
assumptions, that the completion at the ideal m + < y_1,y_2,ldots,y_n> is an
iterated skew power series ring. Under further conditions, this completion is a
local, noetherian, Auslander regular domain. Applicable examples include
quantum matrices, quantum symplectic spaces, and quantum Euclidean space.


title:
An Imaging Fabry-Perot System for the Robert Stobie Spectrograph on the
  Southern African Large Telescope

abstract:
  We present the design of the Fabry-Perot system of the Robert Stobie
Spectrograph on the 10-meter class Southern African Large Telescope and its
characterization as measured in the laboratory. This system provides
spectroscopic imaging at any desired wavelength spanning a bandpass 430 - 860
nm, at four different spectral resolving powers ranging from 300 to 9000. Our
laboratory tests revealed a wavelength dependence of the etalon gap and
parallelism with a maximum variation between 600 - 720 nm that arises because
of the complex structure of the broadband multi-layer dielectric coatings. We
also report an unanticipated optical effect of this multi-layer coating
structure that produces a significant, and wavelength dependent, change in the
apparent shape of the etalon plates. This change is caused by two effects: the
physical non-uniformities or thickness variations in the coating layers, and
the wavelength dependence of the phase change upon refection that can amplify
these non-uniformities. We discuss the impact of these coating effects on the
resolving power, finesse, and throughput of the system. This Fabry-Perot system
will provide a powerful tool for imaging spectroscopy on one of the world's
largest telescopes.


title: Crime and punishment: the economic burden of impunity

abstract:
  Crime is an economically important activity, sometimes called the industry of
crime. It may represent a mechanism of wealth distribution but also a social
and economic charge because of the cost of the law enforcement system.
Sometimes it may be less costly for the society to allow for some level of
criminality. A drawback of such policy may lead to a high increase of criminal
activity that may become hard to reduce. We investigate the level of law
enforcement required to keep crime within acceptable limits and show that a
sharp phase transition is observed as a function of the probability of
punishment. We also analyze the growth of the economy, the inequality in the
wealth distribution (the Gini coefficient) and other relevant quantities under
different scenarios of criminal activity and probability of apprehension.


title:
First joint Gravitational Waves search by the
  Auriga-Explorer-Nautilus-Virgo collaboration

abstract:
  We present results of the search for coincident burst excitations over a 24
hours long data set collected by AURIGA, EXPLORER, NAUTILUS and Virgo detectors
during September 2005. The search of candidate triggers was performed
independently on each of the data sets from single detectors. We looked for
two-fold time coincidences between these candidates using an algorithm
optimized for a given population of sources and we calculated the efficiency of
detection through injections of templated signal waveforms into the streams of
data. To this purpose we have considered the case of signals shaped as damped
sinusoids coming from the galactic center direction. In this framework our
method targets an optimal balance between high efficiency and low false alarm
rate, aiming at setting confidence intervals as stringent as possible in terms
of the rate of the selected source models.


title: A very faint core-collapse supernova in M85

abstract:
  An anomalous transient in the early Hubble-type (S0) galaxy Messier 85 (M85)
in the Virgo cluster was discovered by Kulkarni et al. (2007) on 7 January 2006
that had very low luminosity (peak absolute R-band magnitude MR of about -12)
that was constant over more than 80 days, red colour and narrow spectral lines,
which seem inconsistent with those observed in any known class of transient
events. Kulkarni et al. (2007) suggest an exotic stellar merger as the possible
origin. An alternative explanation is that the transient in M85 was a type
II-plateau supernova of extremely low luminosity, exploding in a lenticular
galaxy with residual star-forming activity. This intriguing transient might be
the faintest supernova that has ever been discovered.


title:
Mid-Infrared Photometry and Spectra of Three High Mass Protostellar
  Candidates at IRAS 18151-1208 and IRAS 20343+4129

abstract:
  We present arcsecond-scale mid-ir photometry (in the 10.5 micron N band and
at 24.8 microns), and low resolution spectra in the N band (R~100) of a
candidate high mass protostellar object (HMPO) in IRAS 18151-1208 and of two
HMPO candidates in IRAS 20343+4129, IRS 1 and IRS 3. In addition we present
high resolution mid-ir spectra (R~80000) of the two HMPO candidates in IRAS
20343+4129. These data are fitted with simple models to estimate the masses of
gas and dust associated with the mid-ir emitting clumps, the column densities
of overlying absorbing dust and gas, the luminosities of the HMPO candidates,
and the likely spectral type of the HMPO candidate for which [Ne II] 12.8
micron emission was detected (IRAS 20343+4129 IRS 3). We suggest that IRAS
18151-1208 is a pre-ultracompact HII region HMPO, IRAS 20343+4129 IRS 1 is an
embedded young stellar object with the luminosity of a B3 star, and IRAS
20343+4129 IRS 3 is a B2 ZAMS star that has formed an ultracompact HII region
and disrupted its natal envelope.


title: The Standard Model Higgs boson as the inflaton

abstract:
  We argue that the Higgs boson of the Standard Model can lead to inflation and
produce cosmological perturbations in accordance with observations. An
essential requirement is the non-minimal coupling of the Higgs scalar field to
gravity; no new particle besides already present in the electroweak theory is
required.


title: Complex Langevin Equations and Schwinger-Dyson Equations

abstract:
  Stationary distributions of complex Langevin equations are shown to be the
complexified path integral solutions of the Schwinger-Dyson equations of the
associated quantum field theory. Specific examples in zero dimensions and on a
lattice are given. Relevance to the study of quantum field theory phase space
is discussed.


title: Inferring the conditional mean

abstract:
  Consider a stationary real-valued time series $\{X_n\}_{n=0}^{\infty}$ with a
priori unknown distribution. The goal is to estimate the conditional
expectation $E(X_{n+1}|X_0,..., X_n)$ based on the observations $(X_0,...,
X_n)$ in a pointwise consistent way. It is well known that this is not possible
at all values of $n$. We will estimate it along stopping times.


title: Heating mechanism affects equipartition in a binary granular system

abstract:
  Two species of particles in a binary granular system typically do not have
the same mean kinetic energy, in contrast to the equipartition of energy
required in equilibrium. We investigate the role of the heating mechanism in
determining the extent of this non-equipartition of kinetic energy. In most
experiments, different species of particle are unequally heated at the
boundaries. We show by event-driven simulations that this differential heating
at the boundary influences the level of non-equipartition even in the bulk of
the system. This conclusion is fortified by studying a numerical model and a
solvable stochastic model without spatial degrees of freedom. In both cases,
even in the limit where heating events are rare compared to collisions, the
effect of the heating mechanism persists.


title:
Selective Reflection Spectroscopy at the Interface between a Calcium
  Fluoride Window and Cs Vapour

abstract:
  A special vapour cell has been built, that allows the measurement of the
atom-surface van der Waals interaction exerted by a CaF2 window at the
interface with Cs vapour. Mechanical and thermal fragility of fluoride windows
make common designs of vapour cells unpractical, so that we have developed an
all-sapphire sealed cell with an internal CaF2 window. Although impurities were
accidentally introduced when filling-up the prototype cell, leading to a
line-broadening and shift, the selective reflection spectrum on the Cs D1 line
(894 nm) makes apparent the weak van der Waals surface interaction. The
uncertainties introduced by the effects of these impurities in the van der
Waals measurement are nearly eliminated when comparing the selective reflection
signal at the CaF2 interface of interest, and at a sapphire window of the same
cell. The ratio of the interaction respectively exerted by a sapphire interface
and a CaF2 interface is found to be 0.55 $\pm$ 0.25, in good agreement with the
theoretical evaluation of ~0.67.


title: Guessing the output of a stationary binary time series

abstract:
  The forward prediction problem for a binary time series
$\{X_n\}_{n=0}^{\infty}$ is to estimate the probability that $X_{n+1}=1$ based
on the observations $X_i$, $0\le i\le n$ without prior knowledge of the
distribution of the process $\{X_n\}$. It is known that this is not possible if
one estimates at all values of $n$. We present a simple procedure which will
attempt to make such a prediction infinitely often at carefully selected
stopping times chosen by the algorithm. The growth rate of the stopping times
is also exhibited.


title:
Extraordinary surface voltage effect in the invisibility cloak with an
  active device inside

abstract:
  The electromagnetic field solution for a spherical invisibility cloak with an
active device inside is established. Extraordinary electric and magnetic
surface voltages are induced at the inner boundary of a spherical cloak, which
prevent electromagnetic waves from going out. The phase and handness of
polarized waves obliquely incident on such boundaries is kept in the reflected
waves. The surface voltages due to an electric dipole inside the concealed
region are found equal to the auxiliary scalar potentials at the inner
boundary, which consequently gain physical counterparts in this case.


title: Exponential decay in a spin bath

abstract:
  We show that the coherence of an electron spin interacting with a bath of
nuclear spins can exhibit a well-defined purely exponential decay for special
(`narrowed') bath initial conditions in the presence of a strong applied
magnetic field. This is in contrast to the typical case, where spin-bath
dynamics have been investigated in the non-Markovian limit, giving
super-exponential or power-law decay of correlation functions. We calculate the
relevant decoherence time T_2 explicitly for free-induction decay and find a
simple expression with dependence on bath polarization, magnetic field, the
shape of the electron wave function, dimensionality, total nuclear spin I, and
isotopic concentration for experimentally relevant heteronuclear spin systems.


title:
Supernova rates from the Southern inTermediate Redshift ESO Supernova
  Search (STRESS)

abstract:
  To measure the supernova (SN) rates at intermediate redshift we performed the
Southern inTermediate Redshift ESO Supernova Search (STRESS). Unlike most of
the current high redshift SN searches, this survey was specifically designed to
estimate the rate for both type Ia and core collapse (CC) SNe. We counted the
SNe discovered in a selected galaxy sample measuring SN rate per unit blue band
luminosity. Our analysis is based on a sample of ~43000 galaxies and on 25
spectroscopically confirmed SNe plus 64 selected SN candidates. Our approach is
aimed at obtaining a direct comparison of the high redshift and local rates and
at investigating the dependence of the rates on specific galaxy properties,
most notably their colour. The type Ia SN rate, at mean redshift z=0.3, amounts
to 0.22^{+0.10+0.16}_{-0.08 -0.14} h_{70}^2 SNu, while the CC SN rate, at
z=0.21, is 0.82^{+0.31 +0.30}_{-0.24 -0.26} h_{70}^2 SNu. The quoted errors are
the statistical and systematic uncertainties. With respect to local value, the
CC SN rate at z=0.2 is higher by a factor of ~2 already at redshift, whereas
the type Ia SN rate remains almost constant. This implies that a significant
fraction of SN Ia progenitors has a lifetime longer than 2-3 Gyr. We also
measured the SN rates in the red and blue galaxies and found that the SN Ia
rate seems to be constant in galaxies of different colour, whereas the CC SN
rate seems to peak in blue galaxies, as in the local Universe. SN rates per
unit volume were found to be consistent with other measurements showing a
steeper evolution with redshift for CC SNe with respect to SNe Ia. Finally we
have exploited the link between star formation (SF) and SN rates to predict the
evolutionary behaviour of the SN rates and compare it with the path indicated
by observations.


title:
Design of a Distributed Reachability Algorithm for Analysis of Linear
  Hybrid Automata

abstract:
  This paper presents the design of a novel distributed algorithm d-IRA for the
reachability analysis of linear hybrid automata. Recent work on iterative
relaxation abstraction (IRA) is leveraged to distribute the computational
problem among multiple computational nodes in a non-redundant manner by
performing careful infeasibility analysis of linear programs corresponding to
spurious counterexamples. The d-IRA algorithm is resistant to failure of
multiple computational nodes. The experimental results provide promising
evidence for the possible successful application of this technique.


title: Determinants of rational knots

abstract:
  We study the Fox coloring invariants of rational knots. We express the
propagation of the colors down the twists of these knots and ultimately the
determinant of them with the help of finite increasing sequences whose terms of
even order are even and whose terms of odd order are odd.


title: Equivariant $K$-theory of quaternionic flag manifolds

abstract:
  We consider the manifold $Fl_n(\mathbb{H})=Sp(n)/Sp(1)^n$ of all complete
flags in $\mathbb{H}^n$, where $\mathbb{H}$ is the skew-field of quaternions.
We study its equivariant $K$-theory rings with respect to the action of two
groups: $Sp(1)^n$ and a certain canonical subgroup $T:=(S^1)^n\subset Sp(1)^n$
(a maximal torus). For the first group action we obtain a
Goresky-Kottwitz-MacPherson type description. For the second one, we describe
the ring $K_T(Fl_n(\mathbb{H}))$ as a subring of $K_T(Sp(n)/T)$. This ring is
well known, since $Sp(n)/T$ is a complex flag variety.


title: Magnetism and structure of LixCoO2 and comparison to NaxCoO2

abstract:
  The magnetic properties and structure of LixCoO2 for x between 0.5 and 1.0
are reported. Co4+ is found to be high-spin in LixCoO2 for x between 0.94 and
1.0 and low-spin for x between 0.50 and 0.78. Weak antiferromagnetic coupling
is observed, increasing in strength as more Co4+ is introduced. At an x value
of about 0.65, the temperature-independent contribution to the magnetic
susceptibility and the electronic contribution to the specific heat are
largest. Neutron diffraction analysis reveals that the lithium oxide layer
expands perpendicular to the basal plane and the Li ions displace from their
ideal octahedral sites with decreasing x. A comparison of the structures of the
NaxCoO2 and LixCoO2 systems reveals that the CoO2 layer changes substantially
with alkali content in the former but is relatively rigid in the latter.
Further, the CoO6 octahedra in LixCoO2 are less distorted than those in
NaxCoO2. We postulate that these structural differences strongly influence the
physical properties in the two systems.


title: Atom Interferometry tests of the isotropy of post-Newtonian gravity

abstract:
  We present a test of the local Lorentz invariance of post-Newtonian gravity
by monitoring Earth's gravity with a Mach-Zehnder atom interferometer that
features a resolution of about 8*10^(-9)g/Hz^(1/2), the highest reported thus
far. Expressed within the standard model extension (SME) or Nordtvedt's
anisotropic universe model, the analysis limits four coefficients describing
anisotropic gravity at the ppb level and three others, for the first time, at
the 10ppm level. Using the SME we explicitly demonstrate how the experiment
actually compares the isotropy of gravity and electromagnetism.


title: Exact Wave Solutions to 6D Gauged Chiral Supergravity

abstract:
  We describe a broad class of time-dependent exact wave solutions to 6D gauged
chiral supergravity with two compact dimensions. These 6D solutions are
nontrivial warped generalizations of 4D pp-waves and Kundt class solutions and
describe how a broad class of previously-static compactifications from 6D to 4D
(sourced by two 3-branes) respond to waves moving along one of the
uncompactified directions. Because our methods are generally applicable to any
higher dimensional supergravity they are likely to be of use for finding the
supergravity limit of time-dependent solutions in string theory. The 6D
solutions are interesting in their own right, describing 6D shock waves induced
by high energy particles on the branes, and as descriptions of the near-brane
limit of the transient wavefront arising from a local bubble-nucleation event
on one of the branes, such as might occur if a tension-changing phase
transition were to occur.


title: Cohomogeneity one manifolds and selfmaps of nontrivial degree

abstract:
  We construct natural selfmaps of compact cohomgeneity one manifolds with
finite Weyl group and compute their degrees and Lefschetz numbers. On manifolds
with simple cohomology rings this yields in certain cases relations between the
order of the Weyl group and the Euler characteristic of a principal orbit. We
apply our construction to the compact Lie group SU(3) where we extend identity
and transposition to an infinite family of selfmaps of every odd degree. The
compositions of these selfmaps with the power maps realize all possible degrees
of selfmaps of SU(3).


title: Wilson Loops in Non-Compact U(1) Gauge Theories at Criticality

abstract:
  We study the properties of Wilson loops in three dimensional non-compact U(1)
gauge theories with global abelian symmetries. We use duality in the continuum
and on the lattice, to argue that close to the critical point between the Higgs
and Coulomb phases, all correlators of the Wilson loops are periodic functions
of the Wilson loop charge, Q. The period depends on the global symmetry of the
theory, which determines the magnetic flux carried by the dual particles. For
single flavour scalar electrodynamics, the emergent period is Q = 1. In the
general case of N complex scalars with a U(1)^{N-1} global symmetry, the period
is Q = N. We also give some arguments why this phenomenon does not generalize
to theories with a full non-abelian SU(N) symmetry, where no periodicity in Q
is expected. Implications for lattice simulations, as well as for physical
systems, such as easy plane antiferromagnets and disordered superfluids, are
noted.


title: Oscillations in Procyon A: First results from a multi-site campaign

abstract:
  Procyon A is a bright F5IV star in a binary system. Although the distance,
mass and angular diameter of this star are all known with high precision, the
exact evolutionary state is still unclear. Evolutionary tracks with different
ages and different mass fractions of hydrogen in the core pass, within the
errors, through the observed position of Procyon A in the Hertzsprung-Russell
diagram. For more than 15 years several different groups have studied the
solar-like oscillations in Procyon A to determine its evolutionary state.
Although several studies independently detected power excess in the
periodogram, there is no agreement on the actual oscillation frequencies yet.
This is probably due to either insufficient high-quality data (i.e., aliasing)
or due to intrinsic properties of the star (i.e., short mode lifetimes). Now a
spectroscopic multi-site campaign using 10 telescopes world-wide (minimizing
aliasing effects) with a total time span of nearly 4 weeks (increase the
frequency resolution) is performed to identify frequencies in this star and
finally determine its properties and evolutionary state.


title: Limitations on intermittent forecasting

abstract:
  Bailey showed that the general pointwise forecasting for stationary and
ergodic time series has a negative solution. However, it is known that for
Markov chains the problem can be solved. Morvai showed that there is a stopping
time sequence $\{\lambda_n\}$ such that
$P(X_{\lambda_n+1}=1|X_0,...,X_{\lambda_n}) $ can be estimated from samples
$(X_0,...,X_{\lambda_n})$ such that the difference between the conditional
probability and the estimate vanishes along these stoppping times for all
stationary and ergodic binary time series. We will show it is not possible to
estimate the above conditional probability along a stopping time sequence for
all stationary and ergodic binary time series in a pointwise sense such that if
the time series turns out to be a Markov chain, the predictor will predict
eventually for all $n$.


title: Wave breaking and particle jets in intense inhomogeneous charged beams

abstract:
  This work analyzes the dynamics of inhomogeneous, magnetically focused
high-intensity beams of charged particles. While for homogeneous beams the
whole system oscillates with a single frequency, any inhomogeneity leads to
propagating transverse density waves which eventually result in a singular
density build up, causing wave breaking and jet formation. The theory presented
in this paper allows to analytically calculate the time at which the wave
breaking takes place. It also gives a good estimate of the time necessary for
the beam to relax into the final stationary state consisting of a cold core
surrounded by a halo of highly energetic particles.


title: On classifying processes

abstract:
  We prove several results concerning classifications, based on successive
observations $(X_1,..., X_n)$ of an unknown stationary and ergodic process, for
membership in a given class of processes, such as the class of all finite order
Markov chains.


title: Structure and Evolution of the Opacity of Spiral Disks

abstract:
  The opacity of a spiral disk due to dust absorption influences every
measurement we make of it in the UV and optical. Two separate techniques
directly measure the total absorption by dust in the disk: calibrated distant
galaxy counts and overlapping galaxy pairs. The main results from both so far
are a semi-transparent disk with more opaque arms, and a relation between
surface brightness and disk opacity. In the Spitzer era, SED models of spiral
disks add a new perspective on the role of dust in spiral disks. Combined with
the overall opacity from galaxy counts, they yield a typical optical depth of
the dusty ISM clouds: 0.4 that implies a size of ~60 pc. Work on galaxy counts
is currently ongoing on the ACS fields of M51, M101 and M81. Occulting galaxies
offer the possibility of probing the history of disk opacity from higher
redshift pairs. Evolution in disk opacity could influence distance measurements
(SN1a, Tully-Fisher relation). Here, we present first results from
spectroscopically selected occulting pairs in the SDSS. The redshift range for
this sample is limited, but does offer a first insight into disk opacity
evolution as well as a reference for higher redshift measurements.


title: A Deterministic Approach to Wireless Relay Networks

abstract:
  We present a deterministic channel model which captures several key features
of multiuser wireless communication. We consider a model for a wireless network
with nodes connected by such deterministic channels, and present an exact
characterization of the end-to-end capacity when there is a single source and a
single destination and an arbitrary number of relay nodes. This result is a
natural generalization of the max-flow min-cut theorem for wireline networks.
Finally to demonstrate the connections between deterministic model and Gaussian
model, we look at two examples: the single-relay channel and the diamond
network. We show that in each of these two examples, the capacity-achieving
scheme in the corresponding deterministic model naturally suggests a scheme in
the Gaussian model that is within 1 bit and 2 bit respectively from cut-set
upper bound, for all values of the channel gains. This is the first part of a
two-part paper; the sequel [1] will focus on the proof of the max-flow min-cut
theorem of a class of deterministic networks of which our model is a special
case.


title:
Critical points of 2d disordered Dirac fermions: the Quantum Hall
  Transitions revisited

abstract:
  We propose a resolution of the renormalization group flow for the disordered
Dirac fermion theories describing the quantum Hall transition (QHT) and spin
Quantum Hall transition (SQHT), which previously revealed no perturbative fixed
points at 1-loop and higher. The approach involves carrying out the flow in 2
stages, the first stage utilizing a new form of super spin-charge separation to
flow to gl(1|1)_N and osp(2|2)_{-2N} supercurrent algebra theories, where N is
the number of copies. This leads to the unconventional feature that at the
critical point the exponents depend on the original number of copies N. In the
second stage, additional forms of disorder are incorporated as dimension zero
logarithmic operators, and the resulting actions have explicit forms in terms
of two scalar fields and a symplectic fermion. Under some assumptions, the
multi-fractal exponents are computed with the result q(1-q)/4 and q(1-q)/8 for
the QHT and SQHT respectively, and are within a few percent of numerical
estimates.

categories: cond-mat.mes-hall cond-mat.dis-nn hep-th math-ph math.MP


title: Testing D-Sequences for their Randomness

abstract:
  This paper examines the randomness of d-sequences, which are decimal
sequences to an arbitrary base. Our motivation is to check their suitability
for application to cryptography, spread-spectrum systems and use as
pseudorandom sequence.


title: The Galaxy Content of SDSS Clusters and Groups

abstract:
  Imaging data from the Sloan Digital Sky Survey are used to characterize the
population of galaxies in groups and clusters detected with the MaxBCG
algorithm. We investigate the dependence of Brightest Cluster Galaxy (BCG)
luminosity, and the distributions of satellite galaxy luminosity and satellite
color, on cluster properties over the redshift range 0.1 < z < 0.3. The size of
the dataset allows us to make measurements in many bins of cluster richness,
radius and redshift. We find that, within r_200 of clusters with mass above
3e13 h-1 M_sun, the luminosity function of both red and blue satellites is only
weakly dependent on richness. We further find that the shape of the satellite
luminosity function does not depend on cluster-centric distance for magnitudes
brighter than ^{0.25}M_i - 5log(h) < -19. However, the mix of faint red and
blue galaxies changes dramatically. The satellite red fraction is dependent on
cluster-centric distance, galaxy luminosity and cluster mass, and also
increases by ~5% between redshifts 0.28 and 0.2, independent of richness. We
find that BCG luminosity is tightly correlated with cluster richness, scaling
as L_{BCG} ~ M_{200}^{0.3}, and has a Gaussian distribution at fixed richness,
with sigma_{log L} ~ 0.17 for massive clusters. The ratios of BCG luminosity to
total cluster luminosity and characteristic satellite luminosity scale strongly
with cluster richness: in richer systems, BCGs contribute a smaller fraction of
the total light, but are brighter compared to typical satellites. This study
demonstrates the power of cross-correlation techniques for measuring galaxy
populations in purely photometric data.


title: Wireless Network Information Flow

abstract:
  We present an achievable rate for general deterministic relay networks, with
broadcasting at the transmitters and interference at the receivers. In
particular we show that if the optimizing distribution for the
information-theoretic cut-set bound is a product distribution, then we have a
complete characterization of the achievable rates for such networks. For linear
deterministic finite-field models discussed in a companion paper [3], this is
indeed the case, and we have a generalization of the celebrated max-flow
min-cut theorem for such a network.


title: On the localization theorem for F-pure rings

abstract:
  We solve Grothendieck's localization problem for certain class of rings
arising from the tight closure theory. The idea of the proof depends heavily on
the study of the relative version of the Frobenius map.


title:
Search for axion-like particles using a variable baseline photon
  regeneration technique

abstract:
  We report the first results of the GammeV experiment, a search for milli-eV
mass particles with axion-like couplings to two photons. The search is
performed using a "light shining through a wall" technique where incident
photons oscillate into new weakly interacting particles that are able to pass
through the wall and subsequently regenerate back into detectable photons. The
oscillation baseline of the apparatus is variable, thus allowing probes of
different values of particle mass. We find no excess of events above background
and are able to constrain the two-photon couplings of possible new scalar
(pseudoscalar) particles to be less than 3.1x10^{-7} GeV^{-1} (3.5x10^{-7}
GeV^{-1}) in the limit of massless particles.


title: Evolution of Complexity

abstract:
  The evolution of complexity has been a central theme for Biology [2] and
Artificial Life research [1]. It is generally agreed that complexity has
increased in our universe, giving way to life, multi-cellularity, societies,
and systems of higher complexities. However, the mechanisms behind the
complexification and its relation to evolution are not well understood.
Moreover complexification can be used to mean different things in different
contexts. For example, complexification has been interpreted as a process of
diversification between evolving units [2] or as a scaling process related to
the idea of transitions between different levels of complexity [7].
Understanding the difference or overlap between the mechanisms involved in both
situations is mandatory to create acceptable synthetic models of the process,
as is required in Artificial Life research. (...)


title: Outflow and Accretion in Massive Star Forming Regions

abstract:
  In order to distinguish between the various components of massive star
forming regions (i.e. infalling, outflowing and rotating gas structures) within
our own Galaxy, we require high angular resolution observations which are
sensitive to structures on all size scales. To this end, we present
observations of the molecular and ionized gas towards massive star forming
regions at 230 GHz from the SMA (with zero spacing from the JCMT) and at 22 and
23 GHz from the VLA at arcsecond or better resolution. These observations (of
sources such as NGC7538, W51e2 and K3-50A) form an integral part of a
multi-resolution study of the molecular and ionized gas dynamics of massive
star forming regions (i.e. Klaassen & Wilson 2007). Through comparison of these
observations with 3D radiative transfer models, we hope to be able to
distinguish between various modes of massive star formation, such as ionized or
halted accretion (i.e Keto 2003 or Klaassen et al. 2006 respectively).


title: Reducible And Finite Dehn Fillings

abstract:
  We show that the distance between a finite filling slope and a reducible
filling slope on the boundary of a hyperbolic knot manifold is at most one.


title: Quantum Stress Tensor Fluctuations and their Physical Effects

abstract:
  We summarize several aspects of recent work on quantum stress tensor
fluctuations and their role in driving fluctuations of the gravitational field.
The role of correlations and anticorrelations is emphasized. We begin with a
review of the properties of the stress tensor correlation function. We next
consider some illuminating examples of non-gravitational effects of stress
tensors fluctuations, specifically fluctuations of the Casimir force and
radiation pressure fluctuations. We next discuss passive fluctuations of
spacetime geometry and some of their operational signatures. These include
luminosity fluctuations, line broadening, and angular blurring of a source
viewed through a fluctuating gravitational field. Finally, we discuss the
possible role of quantum stress tensor fluctuations in the early universe,
especially in inflation. The fluctuations of the expansion of a congruence of
comoving geodesics grows during the inflationary era, due to non-cancellation
of anticorrelations that would have occurred in flat spacetime. This results in
subsequent non-Gaussian density perturbations and allows one to infer an upper
bound on the duration of inflation. This bound is consistent with adequate
inflation to solve the horizon and flatness problems.


title:
Instanton Packet Formation via a Wormhole Bridge between a Prior to our
  Present Universe, and criteria for their possible break up

abstract:
  We present a criteria for necessary conditions for instanton formation of an
energy packet from a prior to our present universe, using the
Reissnor-Nordstrom metric which is congruent with Crowell's pseudo time
evolution version of Wheeler De Witt equation. This is based upon Wesson's
(1999) treatment of instanton formation in five dimensional cosmologies.
Criteria for break up of this instanton is proposed due to a causal barrier
derived from first principles From the Friedmann equation for scale factor
evolution, with a discussion of how this can be linked to Seth Lloyd's
treatment of computational bits of 'information' in different periods of
inflationary cosmology


title:
Frequency Analysis of Decoupling Capacitors for Three Voltage Supplies
  in SoC

abstract:
  Reduction in power consumption has become a major criterion of design in
modern ICs. One such scheme to reduce power consumption by an IC is the use of
multiple power supplies for critical and non-critical paths. To maintain the
impedance of a power distribution system below a specified level, multiple
decoupling capacitors are placed at different levels of power grid hierarchy.
This paper describes about three-voltage supply power distribution systems. The
noise at one power supply can propagate to the other power supply, causing
power and signal integrity problems in the overall system. Effects such as
anti-resonance and remedies for these effects are studied. Impedance of the
three-voltage supply power distribution system is calculated in terms of
RLC-model of decoupling capacitors. Further the obtained impedance depends on
the frequency; hence brief frequency analysis of impedance is done.


title: f(R)-Brane

abstract:
  We investigate the existence of brane solutions in braneworld scenarios
described by real scalar field in the presence of modified $f(R)$ gravity with
a single extra dimension. In the case of constant curvature, we obtain
first-order differential equations which solve the equations of motion and ease
the search for explicit analytical solutions. Several examples of current
interest are investigated to illustrate the results of the present work.


title: New constraints on supersymmetric models from b -> s gamma

abstract:
  We provide an analysis of the parameter space of several supersymmetry
breaking scenarios such as the minimal supergravity (mSUGRA) model and the non
universal Higgs mass (NUHM) framework, as well as the Anomaly Mediated
Supersymmetry Breaking (AMSB) and the Gauge Mediated Supersymmetry Breaking
(GMSB) models, in the light of a novel observable in b -> s gamma transitions,
i.e. the isospin symmetry breaking in the exclusive B -> K* gamma decays. We
find that in many cases, this observable provides severe restrictions on the
allowed parameter space regions for the mentioned models. Moreover, we provide
a few examples of investigations of the physical masses of supersymmetric
particles and search for the excluded values. The constraints from the
branching ratio associated to b -> s gamma are also presented here for all the
examined parameter space regions. A comparison with B_s -> mu+ mu- branching
ratio has also been performed.


title: Approximating critical parameters of branching random walks

abstract:
  Given a branching random walk on a graph, we consider two kinds of
truncations: by inhibiting the reproduction outside a subset of vertices and by
allowing at most $m$ particles per site. We investigate the convergence of weak
and strong critical parameters of these truncated branching random walks to the
analogous parameters of the original branching random walk. As a corollary, we
apply our results to the study of the strong critical parameter of a branching
random walk restricted to the cluster of a Bernoulli bond percolation.


title: Depressed Surface Magnetization in Thin La0.8MnO3 Films

abstract:
  A systematic study the magnetization in La0.8.MnO3 films of thickness varying
from ultra-thin to bulk-like has been conducted. The study reveals suppression
of the bulk magnetization for films up to at least 1600 A. In addition, the
surface (top 50 A) of all films exhibits depressed magnetization as observed by
x-ray magnetic circular dichroism (XMCD). The reduced surface magnetization is
attributed to the coexistence of magnetic and nonmagnetic components of the
same chemical composition.


title: Curve complexes are rigid

abstract:
  Any quasi-isometry of the complex of curves is bounded distance from a
simplicial automorphism. As a consequence, the quasi-isometry type of the curve
complex determines the homeomorphism type of the surface.


title:
Localizing coalescing massive black hole binaries with gravitational
  waves

abstract:
  Massive black hole binary coalescences are prime targets for space-based
gravitational wave (GW) observatories such as {\it LISA}. GW measurements can
localize the position of a coalescing binary on the sky to an ellipse with a
major axis of a few tens of arcminutes to a few degrees, depending on source
redshift, and a minor axis which is $2 - 4$ times smaller. Neglecting weak
gravitational lensing, the GWs would also determine the source's luminosity
distance to better than percent accuracy for close sources, degrading to
several percent for more distant sources. Weak lensing cannot, in fact, be
neglected and is expected to limit the accuracy with which distances can be
fixed to errors no less than a few percent. Assuming a well-measured cosmology,
the source's redshift could be inferred with similar accuracy. GWs alone can
thus pinpoint a binary to a three-dimensional ``pixel'' which can help guide
searches for the hosts of these events. We examine the time evolution of this
pixel, studying it at merger and at several intervals before merger. One day
before merger, the major axis of the error ellipse is typically larger than its
final value by a factor of $\sim 1.5-6$. The minor axis is larger by a factor
of $\sim 2-9$, and, neglecting lensing, the error in the luminosity distance is
larger by a factor of $\sim 1.5-7$. This large change over a short period of
time is due to spin-induced precession, which is strongest in the final days
before merger. The evolution is slower as we go back further in time. For $z =
1$, we find that GWs will localize a coalescing binary to within $\sim 10\
\mathrm{deg}^2$ as early as a month prior to merger and determine distance (and
hence redshift) to several percent.


title: Sweet Spot Supersymmetry and Composite Messengers

abstract:
  Sweet spot supersymmetry is a phenomenologically and cosmologically perfect
framework to realize a supersymmetric world at short distance. We discuss a
class of dynamical models of supersymmetry breaking and its mediation whose
low-energy effective description falls into this framework. Hadron fields in
the dynamical models play a role of the messengers of the supersymmetry
breaking. As is always true in the models of the sweet spot supersymmetry, the
messenger scale is predicted to be 10^5 GeV < M_mess < 10^{10} GeV. Various
values of the effective number of messenger fields N_mess are possible
depending on the choice of the gauge group.


title: Two-dimensional magnetoexcitons in the presence of spin-orbit coupling

abstract:
  We study theoretically the effect of spin-orbit coupling on quantum well
excitons in a strong magnetic field. We show that, in the presence of an
in-plane field component, the excitonic absorption spectrum develops a
double-peak structure due to hybridization of bright and dark magnetoexcitons.
If the Rashba and Dresselhaus spin-orbit constants are comparable, the
magnitude of splitting can be tuned in a wide interval by varying the azimuthal
angle of the in-plane field. We also show that the interplay between spin-orbit
and Coulomb interactions leads to an anisotropy of exciton energy dispersion in
the momentum plane. The results suggest a way for direct optical measurements
of spin-orbit parameters.


title: The moduli space of parallelizable 4-manifolds

abstract:
  In this paper we construct the space of smooth 4-manifolds and find the
homotopy model for the connected components of the complement to the
discriminant.
  The discriminant of this space is a singular hypersurface and its generic
points correspond to manifolds with isolated Morse singularities.
  These spaces can be considered as a natural base for the recent theories
studying invariants for families. We show that the theory of Bauer and Furuta
can be raised to parametrized families on our configurational space and their
invariant is the step-function on chambers.
  We also introduce the definition of the invariant of finite type and give a
simple example of an invariant of order one.


title: On the Physics Case of a Super Flavour Factory

abstract:
  We summarize the physics case of a high-luminosity e+e- flavour factory
collecting an integrated luminosity of 50-75 ab^(-1). Many New Physics
sensitive measurements involving B and D mesons and tau leptons, unique to a
Super Flavour Factory, can be performed with excellent sensitivity to new
particles with masses up to ~100 (or even ~1000 TeV). Flavour- and CP-violating
couplings of new particles that may be discovered at the LHC can be measured in
most scenarios, even in unfavourable cases assuming minimal flavour violation.
Together with the LHC, a Super Flavour Factory, following either the SuperKEKB
or the SuperB proposal, could be soon starting the project of reconstructing
the New Physics Lagrangian.


title: Community Detection via Facility Location

abstract:
  In this paper we apply theoretical and practical results from facility
location theory to the problem of community detection in networks. The result
is an algorithm that computes bounds on a minimization variant of local
modularity. We also define the concept of an edge support and a new measure of
the goodness of community structures with respect to this concept. We present
preliminary results and note that our methods are massively parallelizable.


title: Levi-flat hypersurfaces with real analytic boundary

abstract:
  Let $X$ be a Stein manifold of dimension at least 3. Given a compact
codimension 2 real analytic submanifold $M$ of $X$, that is the boundary of a
compact Levi-flat hypersurface $H$, we study the regularity of $H$. Suppose
that the CR singularities of $M$ are an $\mathcal{O}(X)$-convex set. For
example, suppose $M$ has only finitely many CR singularities, which is a
generic condition. Then $H$ must in fact be a real analytic submanifold. If $M$
is real algebraic, it follows that $H$ is real algebraic and in fact extends
past $M$, even near CR singularities. To prove these results we provide two
variations on a theorem of Malgrange, that a smooth submanifold contained in a
real analytic subvariety of the same dimension is itself real analytic. We
prove a similar theorem for submanifolds with boundary, and another one for
subanalytic sets.


title:
A Posteriori Equivalence: A New Perspective for Design of Optimal
  Channel Shortening Equalizers

abstract:
  The problem of channel shortening equalization for optimal detection in ISI
channels is considered. The problem is to choose a linear equalizer and a
partial response target filter such that the combination produces the best
detection performance. Instead of using the traditional approach of MMSE
equalization, we directly seek all equalizer and target pairs that yield
optimal detection performance in terms of the sequence or symbol error rate.
This leads to a new notion of a posteriori equivalence between the equalized
and target channels with a simple characterization in terms of their underlying
probability distributions. Using this characterization we show the surprising
existence an infinite family of equalizer and target pairs for which any
maximum a posteriori (MAP) based detector designed for the target channel is
simultaneously MAP optimal for the equalized channel. For channels whose input
symbols have equal energy, such as q-PSK, the MMSE equalizer designed with a
monic target constraint yields a solution belonging to this optimal family of
designs. Although, these designs produce IIR target filters, the ideas are
extended to design good FIR targets. For an arbitrary choice of target and
equalizer, we derive an expression for the probability of sequence detection
error. This expression is used to design optimal FIR targets and IIR equalizers
and to quantify the FIR approximation penalty.


title: Massive expanding torus and fast outflow in planetary nebula NGC 6302

abstract:
  We present interferometric observations of $^{12}$CO and $^{13}$CO $J$=2$-$1
emission from the butterfly-shaped, young planetary nebula NGC 6302. The high
angular resolution and high sensitivity achieved in our observations allow us
to resolve the nebula into two distinct kinematic components: (1) a massive
expanding torus seen almost edge-on and oriented in the North-South direction,
roughly perpendicular to the optical nebula axis. The torus exhibits very
complex and fragmentated structure; (2) high velocity molecular knots moving at
high velocity, higher than 20 \kms, and located in the optical bipolar lobes.
These knots show a linear position-velocity gradient (Hubble-like flow), which
is characteristic of fast molecular outflow in young planetary nebulae. From
the low but variable $^{12}$CO/$^{13}$CO $J$=2$-$1 line intensity ratio we
conclude that the $^{12}$CO $J$=2$-$1 emission is optically thick over much of
the nebula. Using the optically thinner line $^{13}$CO $J$=2$-$1 we estimate a
total molecular gas mass of $\sim$ 0.1 M$_\odot$, comparable to the ionized gas
mass; the total gas mass of the NGC 6302 nebula, including the massive ionized
gas from photon dominated region, is found to be $\sim$ 0.5 M$_\odot$. From
radiative transfer modelling we infer that the torus is seen at inclination
angle of 75$^\circ$ with respect to the plane of the sky and expanding at
velocity of 15 \kms. Comparison with recent observations of molecular gas in
NGC 6302 is also discussed.


title: Random subcubes as a toy model for constraint satisfaction problems

abstract:
  We present an exactly solvable random-subcube model inspired by the structure
of hard constraint satisfaction and optimization problems. Our model reproduces
the structure of the solution space of the random k-satisfiability and
k-coloring problems, and undergoes the same phase transitions as these
problems. The comparison becomes quantitative in the large-k limit. Distance
properties, as well the x-satisfiability threshold, are studied. The model is
also generalized to define a continuous energy landscape useful for studying
several aspects of glassy dynamics.


title:
Cherenkov Flashes and Fluorescence Flares on Telescopes: New lights on
  UHECR Spectroscopy while unveiling Neutrinos Astronomy

abstract:
  Cherenkov Telescopes (as Magic, Hess and Veritas), while pointing
horizontally should reveal also the fluorescence flare tails of nearby
down-going air-showers. Such air-showers, born at higher (tens km) altitudes,
are growing and extending up to lowest atmospheres (EeVs) or up to higher (few
km) quotas (PeVs). Viceversa, as it has been foreseen and only recently
observed, the opposite takes place. Fluorescence Telescopes made for UHECR
detection may be blazed by inclined Cherenkov lights. The geomagnetic splitting
may tag the energy as well as the inclined shower footprint as seen in a recent
peculiar event in AUGER. Additional stereoscopic detection may define the event
origination distance and its consequent primary composition, extending our
understanding on UHECR composition, while unveling a novel tau Neutrino
Astronomy.


title: Internal shocks in relativistic jets with time--dependent sources

abstract:
  We present a ballistic description of the formation and propagation of the
working surface of a relativistic jet. Using simple laws of conservation of
mass and linear momentum at the working surface, we obtain a full description
of the working surface flow parametrised by the initial velocity and mass
injection rate. This allows us to compute analytically the energy release at
any time in the working surface. We compare this model with the results
obtained numerically through a new hydrodynamical code applied to the
propagation of a relativistic fluid in one dimension in order to test the
limits of our study. Finally, we compare our analytical results with observed
light curves of five long gamma ray bursts and show that our model is in very
good agreement with observations using simple periodic variations of the
injected velocity profiles. This simple method allows us to recover initial
mass discharge and energy output ejected during the burst.


title:
Directed destabilization of lysozyme in protic ionic liquids reveals a
  compact, low energy, soluble, reversibly-unfolding (pre-fibril) state

abstract:
  Recent demonstrations of extraordinary stabilization of proteins in mobile
protic [1] and aprotic [2] ionic liquid solutions at ambient temperatures have
raised hopes of new biopreservation and drug transportation technologies. Here
we examine the relation of folded protein stability to the state of the
transferred proton [1], as determined by the N-H proton chemical shift, d(N-H).
We identify a range of d(N-H) in which the unfolded lysozyme refolds 97%.
Exceeding the stability range in the acid direction leads to the sudden
formation and stabilization of a small, soluble, amyloid form of lysozyme which
has its own stability range and which can again unfold/refold many times before
an irreversible process, fibrillization, occurs. The tightly bound amyloid form
of the lysozyme molecule, identified by circular dichroism spectra and dynamic
light scattering, must be of very low energy since the unfolding process
absorbs almost three times the enthalpy of normal lysozyme unfolding.
alpha-lactalbumin shows similar behavior.


title:
Finite Mirror Effects in Advanced Interferometric Gravitational Wave
  Detectors

abstract:
  Thermal noise is expected to be the dominant source of noise in the most
sensitive frequency band of second generation ground based gravitational wave
detectors. Reshaping the beam to a flatter wider profile which probes more of
the mirror surface reduces this noise. The "Mesa" beam shape has been proposed
for this purpose and was subsequently generalized to a family of hyperboloidal
beams with two parameters: twist angle alpha and beam width D. Varying alpha
allows a continuous transition from the nearly-flat to the nearly-concentric
Mesa beam configurations. We analytically prove that in the limit of infinite D
hyperboloidal beams become Gaussians. The Advanced LIGO diffraction loss design
constraint is 1 ppm per bounce. In the past the diffraction loss has often been
calculated using the clipping approximation that, in general, underestimates
the diffraction loss. We develop a code using pseudo-spectral methods to
compute the diffraction loss directly from the propagator. We find that the
diffraction loss is not a strictly monotonic function of beam width, but has
local minima that occur due to finite mirror effects and leads to natural
choices of D. For the Mesa beam a local minimum occurs at D = 10.67 cm and
leads to a diffraction loss of 1.4 ppm. We find that if one requires a
diffraction loss of strictly 1 ppm, the alpha = 0.91 pi hyperboloidal beam is
optimal, leading to the coating thermal noise being lower by about 10% than for
a Mesa beam while other types of thermal noise decrease as well. We then
develop an iterative process that reconstructs the mirror to specifically
account for finite mirror effects. This allows us to increase the D parameter
and lower the coating noise by about 30% compared to the original Mesa
configuration.


title:
A precessing jet model for the PN K 3-35: simulated radio-continuum
  emission

abstract:
  The bipolar morphology of the planetary nebula (PN) K 3-35 observed in
radio-continuum images was modelled with 3D hydrodynamic simulations with the
adaptive grid code yguazu-a. We find that the observed morphology of this PN
can be reproduced considering a precessing jet evolving in a dense AGB
circumstellar medium, given by a mass loss rate
\dot{M}_{csm}=5x10^{-5}M_{\odot}/yr and a terminal velocity v_{w}=10 km/s.
Synthetic thermal radio-continuum maps were generated from numerical results
for several frequencies. Comparing the maps and the total fluxes obtained from
the simulations with the observational results, we find that a model of
precessing dense jets, where each jet injects material into the surrounding CSM
at a rate \dot{M}_j=2.8x10^{-4} {M_{\odot}/yr (equivalent to a density of
8x10^{4} {cm}^{-3}, a velocity of 1500 km/s, a precession period of 100 yr, and
a semi-aperture precession angle of 20 degrees agrees well with the
observations.


title:
On the number of tetrahedra with minimum, unit, and distinct volumes in
  three-space

abstract:
  We formulate and give partial answers to several combinatorial problems on
volumes of simplices determined by $n$ points in 3-space, and in general in $d$
dimensions. (i) The number of tetrahedra of minimum (nonzero) volume spanned by
$n$ points in $\RR^3$ is at most ${2/3}n^3-O(n^2)$, and there are point sets
for which this number is ${3/16}n^3-O(n^2)$. We also present an $O(n^3)$ time
algorithm for reporting all tetrahedra of minimum nonzero volume, and thereby
extend an algorithm of Edelsbrunner, O'Rourke, and Seidel. In general, for
every $k,d\in \NN$, $1\leq k \leq d$, the maximum number of $k$-dimensional
simplices of minimum (nonzero) volume spanned by $n$ points in $\RR^d$ is
$\Theta(n^k)$. (ii) The number of unit-volume tetrahedra determined by $n$
points in $\RR^3$ is $O(n^{7/2})$, and there are point sets for which this
number is $\Omega(n^3 \log \log{n})$. (iii) For every $d\in \NN$, the minimum
number of distinct volumes of all full-dimensional simplices determined by $n$
points in $\RR^d$, not all on a hyperplane, is $\Theta(n)$.


title: Coherent population oscillation from a Fermi atom-molecule dark state

abstract:
  We show that a robust macroscopic atom-molecule dark state can exist in
fermionic systems, which represents a coherent superposition between the ground
molecular BEC and the atomic BCS paired state. We take advantage of the
tunability offered by external laser fields, and explore this superposition for
demonstrating coherent oscillations between ground molecules and atom pairs. We
interpret the oscillation frequencies in terms of the collective excitations of
the dark state.


title: Flow- and Diffusion Distributed Structures with noise at the inlet

abstract:
  Flow and Diffusion Distributed Structures (FDS) are stationary spatially
periodic patterns that can be observed in reaction-diffusion-advection systems.
These structures arise when the flow rate exceeds a certain bifurcation point
provided that concentrations of interacting species at the inlet differ from
steady state values and the concentrations are held constant. Normally,
theoretical studies of these patterns are developed without concerning a noise.
In this paper we consider FDS for a more realistic conditions and assume that
the inlet concentrations are perturbed by a small noise. When the flow rate is
small, the FDS is linearly sensitive to noise at the inlet. Even weak
fluctuations destroy the stationary pattern and an oscillatory solution appears
instead. For higher flow rates the instability becomes nonlinear: the pattern
remains unaltered for a weak noise and undergoes the destruction when the noise
amplitude passes a certain threshold. We represent a detailed description of
these effects and examine two scenarios for the stabilization.


title: Shape transformations of a compartmentalized fluid surface

abstract:
  A surface model on compartmentalized spheres is studied by using the Monte
Carlo simulation technique with dynamical triangulations. We found that the
model exhibits a variety of phases: the spherical phase, the tubular phase, the
planar phase, the wormlike planar phase, the wormlike long phase, the wormlike
short phase, and the collapsed phase. It is also shown that almost all phases
are separated from their neighboring phases by first-order transitions.
Mechanical strength of the surface is given only by elastic skeletons, which
are the compartment boundaries, and vertices diffuse freely inside the
compartments. We confirm that the cytoskeletal structure and the lateral
diffusion of vertices are an origin of such a variety of phases.


title: Finsleroid-Finsler Space of Involutive Case

abstract:
  The Finsleroid-Finsler space is constructed over an underlying Riemannian
space by the help of a scalar $g(x)$ and an input 1-form $b$ of unit length.
Explicit form of the entailed tensors, as well as the respective spray
coefficients, is evaluated. The involutive case means the framework in which
the characteristic scalar $g(x)$ may vary in the direction assigned by $b$,
such that $dg=\mu b$ with a scalar $\mu(x)$.
  We show by required calculation that the involutive case realizes through the
$A$-special relation the picture that instead of the Landsberg condition $\dot
A_{ijk}=0$ we have the vanishing $\dot{\al}_{ijk}=0$ with the normalized tensor
$\al_{ijk}=A_{ijk}/||A||$. Under the involutive condition, the derivative
tensor $A_{i|j}$ and the curvature tensor $R^i{}_k$ have explicitly been found,
assuming the input 1-form $b$ be parallel.
  Key words: Finsler metrics, spray coefficients, curvature tensors.


title:
Eigenmodes of elastic vibrations of quaking neutron star encoded in QPOs
  on light curves of SGR flares

abstract:
  The Newtonian solid-mechanical theory of nodeless spheroidal and torsional of
elastic seismic vibrations trapped in the crust of a quaking neutron star is
outlined and applied to the modal classification of the quasi-periodic
oscillations (QPOs) of X-ray luminosity in the aftermath of giant flares in SGR
1806-20 and SGR 1900+14. The presented analysis relies heavily on the
Samuelsson-Andersson identification of the QPOs frequency from the range 30-200
Hz with those for torsional nodeless vibrations of multipole degree in the
interval 2-12. Based on this identification, which is used to fix the input
parameters entering the obtained spectral formulae, we compute frequency
spectrum of nodeless spheroidal elastic vibrations. Particular attention is
given to the low-frequency QPOs in the data for SGR 1806-20 whose physical
origin has been called into question. Our calculations suggest that these
unspecified QPOs are due to nodeless dipole torsional (18 Hz) and dipole
spheroidal (26 Hz) elastic shear vibrations.


title: Uniting the Quiescent Emission and Burst Spectra of Magnetar Candidates

abstract:
  Spectral studies of quiescent emission and bursts of magnetar candidates
using XMM-Newton, Chandra and Swift data are presented. Spectra of both the
quiescent emission and the bursts for most magnetar candidates are reproduced
by a photoelectrically absorbed two blackbody function (2BB). There is a strong
correlation between lower and higher temperatures of 2BB (kT_LT and kT_HT) for
the magnetar candidates of which the spectra are well reproduced by 2BB. In
addition, a square of radius for kT_T (R_LT^2) is well correlated with a square
of radius for kT_HT (R_HT^2). A ratio kT_LT/kT_HT ~ 0.4 is nearly constant
irrespective of objects and/or emission types (i.e., the quiescent emission and
the bursts). This would imply a common emission mechanism among the magnetar
candidates. The relation between the quiescent emission and the bursts might be
analogous to a relation between microflares and solar flares of the sun. Three
AXPs (4U 0142+614, 1RXS J170849.0-400910 and 1E 2259+586) seem to have an
excess above ~7 keV which well agrees with a non-thermal hard component
discovered by INTEGRAL.


title: A Note on Comparison of Error Correction Codes

abstract:
  Use of an error correction code in a given transmission channel can be
regarded as the statistical experiment. Therefore, powerful results from the
theory of comparison of experiments can be applied to compare the performances
of different error correction codes. We present results on the comparison of
block error correction codes using the representation of error correction code
as a linear experiment. In this case the code comparison is based on the
Loewner matrix ordering of respective code matrices. Next, we demonstrate the
bit-error rate code performance comparison based on the representation of the
codes as dichotomies, in which case the comparison is based on the matrix
majorization ordering of their respective equivalent code matrices.


title: Improved Factorization Method in Studying B-meson Decays

abstract:
  B decays are a subject of active research since they provide useful
information on the dynamics of strong and electroweak interactions for testing
the Standard Model (SM) and models beyond and are ideally suited for a critical
analysis of CP violation phenomena. Within the standard model, there exist
certain relations between CP violating rate differences in B decays in the
SU(3) limit, as for example $\Delta (\bar{B}^0 \to \pi^+ \pi^-) = - \Delta
(\bar{B}^0 \to \pi^+ K^-)$. The goal of this letter is to study the direct CP
violation asymmetry in a class of processes where there has been recent
theoretical progress, as for example the B decays into two light pseudoscalars
mesons and into a light pseudoscalar and a light vector meson. We identify
relations between rate asymmetries which are valid in the SU(3) limit in the
standard model and we compute SU(3) breaking corrections to them, going beyond
the naive factorization by using the QCD improved factorization model of Beneke
{\it et al.}. Finally, in some processes as for example $BR(B^- \to
\eta^{\prime} K^-)$, we claim that one has to add SUSY contributions to the
Wilson coefficients. In these cases, we end with a $BR$ depending on three
parameters, whose values are constrained by the experimental data.


title: B \to K^{*} \gamma Decay within MSSM

abstract:
  The paper deals with a next-to-leading order analysis of the radiative $B \to
K^* \gamma$ decay. Working in a PQCD approach, we compute the correction to the
essential form factor, coming from a single gluon exchange with the spectator.
We investigate the supersymmetry effects on the branching ratio and direct CP
asymmetry and constrain the squark mixing parameter $(\delta_{23}^d)_{LR}$.


title: A Brief Introduction to PYTHIA 8.1

abstract:
  The PYTHIA program is a standard tool for the generation of high-energy
collisions, comprising a coherent set of physics models for the evolution from
a few-body hard process to a complex multihadronic final state. It contains a
library of hard processes and models for initial- and final-state parton
showers, multiple parton-parton interactions, beam remnants, string
fragmentation and particle decays. It also has a set of utilities and
interfaces to external programs. While previous versions were written in
Fortran, PYTHIA 8 represents a complete rewrite in C++. The current release is
the first main one after this transition, and does not yet in every respect
replace the old code. It does contain some new physics aspects, on the other
hand, that should make it an attractive option especially for LHC physics
studies.


title: Torsion, Scalar Field and f(\mathcal{R}) Gravity

abstract:
  The role of torsion and a scalar field $\phi$ in gravitation in the
background of a particular class of the Riemann-Cartan geometry is considered
here. Some times ago, a Lagrangian density with Lagrange multipliers has been
proposed by the author which has been obtained by picking some particular terms
from the SO(4,1) Pontryagin density, where the scalar field $\phi$ causes the
de Sitter connection to have the proper dimension of a gauge field. Here it has
been shown that the divergence of the axial torsion gives the Newton's constant
and the scalar field becomes a function of the Ricci scalar $\mathcal{R}$. The
starting Lagrangian then reduces to a Lagrangian representing the metric
$f(\mathcal{R})$ gravity theory.


title:
Explicit approximation of the sum of the reciprocal of the imaginary
  parts of the zeta zeros

abstract:
  In this note, we give some explicit upper and lower bounds for the summation
$\sum_{0<\gamma\leq T}\frac{1}{\gamma}$, where $\gamma$ is the imaginary part
of nontrivial zeros $\rho=\beta+i\gamma$ of $\zeta(s)$.


title:
Eccentric binary black-hole mergers: The transition from inspiral to
  plunge in general relativity

abstract:
  We study the transition from inspiral to plunge in general relativity by
computing gravitational waveforms of non-spinning, equal-mass black-hole
binaries. We consider three sequences of simulations, starting with a
quasi-circular inspiral completing 1.5, 2.3 and 9.6 orbits, respectively, prior
to coalescence of the holes. For each sequence, the binding energy of the
system is kept constant and the orbital angular momentum is progressively
reduced, producing orbits of increasing eccentricity and eventually a head-on
collision. We analyze in detail the radiation of energy and angular momentum in
gravitational waves, the contribution of different multipolar components and
the final spin of the remnant. We find that the motion transitions from
inspiral to plunge when the orbital angular momentum L=L_crit is about 0.8M^2.
For L<L_crit the radiated energy drops very rapidly. Orbits with L of about
L_crit produce our largest dimensionless Kerr parameter for the remnant,
j=J/M^2=0.724. Generalizing a model recently proposed by Buonanno, Kidder and
Lehner to eccentric binaries, we conjecture that (1) j=0.724 is the maximal
Kerr parameter that can be obtained by any merger of non-spinning holes, and
(2) no binary merger (even if the binary members are extremal Kerr black holes
with spins aligned to the orbital angular momentum, and the inspiral is highly
eccentric) can violate the cosmic censorship conjecture.


title: Deterministic Secure Positioning in Wireless Sensor Networks

abstract:
  Properly locating sensor nodes is an important building block for a large
subset of wireless sensor networks (WSN) applications. As a result, the
performance of the WSN degrades significantly when misbehaving nodes report
false location and distance information in order to fake their actual location.
In this paper we propose a general distributed deterministic protocol for
accurate identification of faking sensors in a WSN. Our scheme does \emph{not}
rely on a subset of \emph{trusted} nodes that are not allowed to misbehave and
are known to every node in the network. Thus, any subset of nodes is allowed to
try faking its position. As in previous approaches, our protocol is based on
distance evaluation techniques developed for WSN. On the positive side, we show
that when the received signal strength (RSS) technique is used, our protocol
handles at most $\lfloor \frac{n}{2} \rfloor-2$ faking sensors. Also, when the
time of flight (ToF) technique is used, our protocol manages at most $\lfloor
\frac{n}{2} \rfloor - 3$ misbehaving sensors. On the negative side, we prove
that no deterministic protocol can identify faking sensors if their number is
$\lceil \frac{n}{2}\rceil -1$. Thus our scheme is almost optimal with respect
to the number of faking sensors. We discuss application of our technique in the
trusted sensor model. More precisely our results can be used to minimize the
number of trusted sensors that are needed to defeat faking ones.


title: Product and anti-Hermitian structures on the tangent space

abstract:
  Noting that the complete lift of a Rimannian metric defined on a
differentiable manifold is not 0-homogeneous on the fibers of the tangent
bundle . In this paper we introduce a new lift which is 0-homogeneous. It
determines on slit tangent bundle a pseudo-Riemannian metric, which depends
only on the metric . We study some of the geometrical properties of this
pseudo-Riemannian space and define the natural almost complex structure and
natural almost product structure which preserve the property of homogeneity and
find some new results.


title: R fluids

abstract:
  A theory of collisionless fluids is developed in a unified picture, where
nonrotating figures with anisotropic random velocity component distributions
and rotating figures with isotropic random velocity component distributions,
make adjoints configurations to the same system. R fluids are defined and mean
and rms angular velocities and mean and rms tangential velocity components are
expressed, by weighting on the moment of inertia and the mass, respectively.
The definition of figure rotation is extended to R fluids. The generalized
tensor virial equations are formulated for R fluids and further attention is
devoted to axisymmetric configurations where, for selected coordinate axes, a
variation in figure rotation has to be counterbalanced by a variation in
anisotropy excess and vice versa. A microscopical analysis of systematic and
random motions is performed under a few general hypotheses, by reversing the
sign of tangential or axial velocity components of an assigned fraction of
particles, leaving the distribution function and other parameters unchanged
(Meza 2002). The application of the reversion process to tangential velocity
components, implies the conversion of random motion rotation kinetic energy
into systematic motion rotation kinetic energy. The application of the
reversion process to axial velocity components, implies the conversion of
random motion translation kinetic energy into systematic motion translation
kinetic energy, and the loss related to a change of reference frame is
expressed in terms of systematic (imaginary) motion rotation kinetic energy. A
procedure is sketched for deriving the spin parameter distribution (including
imaginary rotation) from a sample of observed or simulated large-scale
collisionless fluids i.e. galaxies and galaxy clusters.


title: Topological Born-Infeld-dilaton black holes

abstract:
  We construct a new analytic solution of Einstein-Born-Infeld-dilaton theory
in the presence of Liouville-type potentials for the dilaton field. These
solutions describe dilaton black holes with nontrivial topology and nonlinear
electrodynamics. Black hole horizons and cosmological horizons in these
spacetimes, can be a two-dimensional positive, zero or negative constant
curvature surface. The asymptotic behavior of these solutions are neither flat
nor (A)dS. We calculate the conserved and thermodynamic quantities of these
solutions and verify that these quantities satisfy the first law of black hole
thermodynamics.


title:
Masses and magnetic moments of heavy flavour baryons in hyper central
  model

abstract:
  We employ the hyper central approach to study the masses and magnetic moments
of the baryons constituting single charm and beauty quark. The confinement
potential is assumed in the hyper central co-ordinates of the coulomb plus
power potential form.


title:
Multi-scale Entanglement Renormalization Ansatz in Two Dimensions:
  Quantum Ising Model

abstract:
  We propose a symmetric version of the multi-scale entanglement
renormalization Ansatz (MERA) in two spatial dimensions (2D) and use this
Ansatz to find an unknown ground state of a 2D quantum system. Results in the
simple 2D quantum Ising model on the $8\times8$ square lattice are found to be
very accurate even with the smallest non-trivial truncation parameter.

categories: cond-mat.other cond-mat.mes-hall cond-mat.stat-mech cond-mat.str-el physics.comp-ph quant-ph


title:
Spin-Dependent Mass Enhancement under Magnetic Field in the Periodic
  Anderson Model

abstract:
  In order to study the mechanism of the mass enhancement in heavy fermion
compounds in the presence of magnetic field, we study the periodic Anderson
model using the fluctuation exchange approximation. The resulting value of the
mass enhancement factor z^{-1} can become up to 10, which is significantly
larger than that in the single-band Hubbard model. We show that the difference
between the magnitude of the mass enhancement factor of up spin (minority spin)
electrons z^{-1}_up and that of down spin (majority spin) electrons z^{-1}_down
increases by the applied magnetic field B//z, which is consistent with de
Haas-van Alphen measurements for CeCoIn_5, CeRu_2Si_2 and CePd_2Si_2. We
predict that z^{-1}_up >z^{-1}_down in many Ce compounds, whereas z^{-1}_up <
z^{-1}_down in Yb compounds.


title: A truth about Brownian motion in gases and in general

abstract:
  Real thermal motion of gas molecules, free electrons, etc., at long time
intervals (much greater than mean free-flight time) possesses, contrary to its
popular mathematical models, essentially non-Gaussian statistics. A simple
proof of this statement is suggested basing on only the determinism and
reversibility of microscopic dynamics and besides incidentally derived virial
expansion of a path probability distribution of molecular Brownian particle.


title: Superfield Formulation of Nonlinear N=4 Supermultiplets

abstract:
  We propose a unified superfield formulation of N=4 off-shell supermultiplets
in one spacetime dimension using the standard N=4 superspace. The main idea of
our approach is a "gluing" together of two linear supermultiplets along their
fermions. The functions defining such a gluing obey a system of equations. Each
solution of this system provides a new supermultiplet, linear or nonlinear,
modulo equivalence transformations. In such a way we reproduce all known linear
and nonlinear N=4, d=1 supermultiplets and propose some new ones. Particularly
interesting is an explicit construction of nonlinear N=4 hypermultiplets.


title: A silence black hole: Hawking radiation at the Hagedorn temperature

abstract:
  We compute semi-classically the Hawking emission for different types of black
hole in type II string theory. In particular we analyze the thermal transition
between NS5 branes and Little String Theory, finding compelling evidence for
information recovering. We find that once the near horizon limit is taken the
emission of a full family of models is exactly thermal even if back-reaction is
taken into account. Consequently these theories are non-unitary and can not
convey any information about the black hole internal states. It is argue that
this behaviour matches the string theory expectations. We suggest a plausible
reason for the vanishing of the jet-quenching parameter in such theories.


title: Trace ideals for Fourier integral operators with non-smooth symbols II

abstract:
  We consider Fourier integral operators with symbols in modulation spaces and
non-smooth phase functions whose second orders of derivatives belong to certain
types of modulation space. We establish continuity and Schatten-von Neumann
properties of such operators when acting on modulation spaces.


title: The lessons from the running of the tensor-to-scalar ratio

abstract:
  We derive a simple consistency relation from the running of the
tensor-to-scalar ratio. This new relation is first order in the slow-roll
approximation. While for single field models we can obtain what can be found by
using other observables, multi-field cases in general give non-trivial
contributions dependent on the geometry of the field space and the inflationary
dynamics, which can be probed observationally from this relation. The running
of the tensor-to-scalar ratio may be detected by direct laser interferometer
experiments.


title:
Noncommutative real scalar field theory in 2+1 dimensions at finite
  temperature

abstract:
  We study thermal effects for a noncommutative real scalar field in 2+1
dimensions including a Grosse-Wulkenhaar term. Using a perturbative expansion
for the free energy, we deduce some general properties of the corresponding
contributions, in the thermodynamic limit. We show that the model can be
consistently interpreted as defined on a finite volume, which is naturally
determined by the noncommutativity scale.


title:
Potential for regulatory genetic networks of gene expression near a
  stable point

abstract:
  A description for regulatory genetic network based on generalized potential
energy is constructed. The potential energy is derived from the steady state
solution of linearized Fokker-Plank equation, and the result is shown to be
equivalent to the system of coupled oscillators. The correspondence between the
quantities from the mechanical picture and the steady-state fluctuations is
established. Explicit calculation is given for auto-regulatory networks in
which, the force constant associated with the degree of protein is very weak.
Negative feedback not only suppresses the fluctuations but also increases the
steepness of the potential. The results for the fluctuations agree completely
with those obtained from linear noise Fokker-Planck equation.


title:
Momentum and excitation energy dependence of the "waterfalls" in
  cuprates

abstract:
  Using high-resolution angle-resolved photoemission spectroscopy we have
studied the momentum and photon energy dependence of the anomalous high-energy
dispersion, termed "waterfalls", between the Fermi level and 1 eV binding
energy in several high-Tc superconductors. We observe strong changes of the
dispersion between different Brillouin zones and a strong dependence on the
photon energy around 75 eV, which we associate with the resonant photoemission
at the Cu 3p3d_{x^2-y^2} edge. We conclude that the high-energy "waterfall"
dispersion results from a strong suppression of the photoemission intensity at
the center of the Brillouin zone due to matrix element effects and is,
therefore, not an intrinsic feature of the spectral function. This indicates
that the new high energy scale in the electronic structure of cuprates derived
from the "waterfall"-like dispersion may be incorrect.


title:
Dissipative dynamics of the semiconductor-cavity QED with q-deformed
  bosons in the dispersive approximation

abstract:
  In this paper we give fully analytical description of the dynamics of a
collection of $N$-Frenkel excitons in high density regime dispersively coupled
to a single mode cavity field, in the presence of both exciton and cavity-field
dissipations. By using excitonic operators as q-deformed bosonic operators for
the system, we solve analytically the Liouville equation for the density
operator at zero temperature and investigate the influence of the number of
excitons and the effect of both dissipations on dynamical behavior of the
system. We use the solution of master equation to explore the dissipative
dynamics of non-classical properties such as, molecule-field entanglement,
quadrature squeezing of the field, and molecular dipole squeezing. We find that
the non-classical properties are strongly affected by the number of excitons
and also by the existence of both dissipations.


title: Challenge on Ca-48 enrichment for CANDLES double beta decay experiment

abstract:
  Chemical isotope effects of calcium were studied by liquid-liquid extraction
using a crown ether of dicyclohexano-18-crown-6 for the purpose of finding a
cost-effective and efficient way of enrichment of Ca-48 towards the study of
the neutrinoless double beta decay of Ca-48. We evaluated each contribution
ratio of the field shift effect and the hyperfine splitting shift effect to the
mass effect of the calcium isotopes for the first time. The present preliminary
result suggests the contribution of the field shift effect is small, especially
for Ca-40-Ca-48 case, compared with the case of Chromium trichloride-crown in
which the isotope enrichment factors are strongly affected by the field shifts.
These indications are promising towards the mass producion of enriched Ca-48 by
the chemical separation method.


title: Gravitational and Inertial Mass of Casimir Energy

abstract:
  It has been demonstrated, using variational methods, that quantum vacuum
energy gravitates according to the equivalence principle, at least for the
finite Casimir energies associated with perfectly conducting parallel plates.
This conclusion holds independently of the orientation of the plates. We review
these arguments and add further support to this conclusion by considering
parallel semitransparent plates, that is, $\delta$-function potentials, acting
on a massless scalar field, in a spacetime defined by Rindler coordinates. We
calculate the force on systems consisting of one or two such plates undergoing
acceleration perpendicular to the plates. In the limit of small acceleration we
recover (via the equivalence principle) the situation of weak gravity, and find
that the gravitational force on the system is just $M\mathbf{g}$, where
$\mathbf{g}$ is the gravitational acceleration and $M$ is the total mass of the
system, consisting of the mass of the plates renormalized by the Casimir energy
of each plate separately, plus the energy of the Casimir interaction between
the plates. This reproduces the previous result in the limit as the coupling to
the $\delta$-function potential approaches infinity. Extension of this latter
work to arbitrary orientation of the plates, and to general compact quantum
vacuum energy configurations, is under development.


title:
Global Existence Theorem for the Solutions of 3d Navier-Stokes System on
  T3 for small initial data from the space P(a)

abstract:
  We consider 3d Navier-Stokes system with periodic boundary conditions for
small initial data from the space of Pseudomeasures. We provide asymptotic
behavior for the coefficients in the perturbation series for the solution of
this system.


title: H and A Discrimination using Linear Polarization of Photons at the PLC

abstract:
  First realistic estimate of the usefulness of the Photon Linear Collider with
linearly polarized photons as analyzer of the CP-parity of Higgs bosons is
presented. MSSM Higgs bosons H and A with 300 GeV mass, for the model
parameters corresponding to the so called "LHC wedge" region, are considered.
When switching from circular to linear photon polarization a significant
increase in heavy quark production background, which is no longer suppressed by
helicity conservation, and decrease of the Higgs boson production cross
sections by a factor of two is expected. Nevertheless, after three years of
Photon Linear Collider running heavy scalar and pseudoscalar Higgs bosons in
MSSM can be distinguished at a 4.5 sigma level.


title: A new class of examples of group-valued moment maps

abstract:
  The purpose of this paper is to construct new examples of group-valued moment
maps. As the main tool for construction of such examples we use
quasi-symplectic implosion which was introduced in [HJS06]. More precisely we
show that there are certain strata of $D{\bf Sp}(n)_{\rm impl}$, the universal
imploded space, where it is singular but whose closure is a smooth
quasi-Hamiltonian ${\bf Sp}(n) \times T$ space.


title: Symmetry properties of Penrose type tilings

abstract:
  The Penrose tiling is directly related to the atomic structure of certain
decagonal quasicrystals and, despite its aperiodicity, is highly symmetric. It
is known that the numbers 1, $-\tau $, $(-\tau)^2$, $(-\tau)^3$, ..., where
$\tau =(1+\sqrt{5})/2$, are scaling factors of the Penrose tiling. We show that
the set of scaling factors is much larger, and for most of them the number of
the corresponding inflation centers is infinite.


title: Cells and Constructible Representations in type B

abstract:
  We examine the partition of a finite Coxeter group of type $B$ into cells
determined by a weight function $L$. The main objective of these notes is to
reconcile Lusztig's description of constructible representations in this
setting with conjectured combinatorial descriptions of cells.


title:
Coherent transfer of light polarization to electron spins in a
  semiconductor

abstract:
  We demonstrate that the superposition of light polarization states is
coherently transferred to electron spins in a semiconductor quantum well. By
using time-resolved Kerr rotation we observe the initial phase of Larmor
precession of electron spins whose coherence is transferred from light. To
break the electron-hole spin entanglement, we utilized the big discrepancy
between the transverse g-factors of electrons and light holes. The result
encourages us to make a quantum media converter between flying photon qubits
and stationary electron spin qubits in semiconductors.


title: Andreev reflection and Klein tunneling in graphene

abstract:
  This is a colloquium-style introduction to two electronic processes in a
carbon monolayer (graphene), each having an analogue in relativistic quantum
mechanics. Both processes couple electron-like and hole-like states, through
the action of either a superconducting pair potential or an electrostatic
potential. The first process, Andreev reflection, is the electron-to-hole
conversion at the interface with a superconductor. The second process, Klein
tunneling, is the tunneling through a p-n junction. Existing and proposed
experiments on Josephson junctions and bipolar junctions in graphene are
discussed from a unified perspective.
  CONTENTS:
  I. INTRODUCTION
  II. BASIC PHYSICS OF GRAPHENE (Dirac equation; Time reversal symmetry;
Boundary conditions; Pseudo-diffusive dynamics)
  III. ANDREEV REFLECTION (Electron-hole conversion; Retro-reflection vs.
specular reflection; Dirac-Bogoliubov-de Gennes equation; Josephson junctions;
Further reading)
  IV. KLEIN TUNNELING (Absence of backscattering; Bipolar junctions; Magnetic
field effects; Further reading)
  V. ANALOGIES (Mapping between NS and p-n junction; Retro-reflection vs.
negative refraction; Valley-isospin dependent quantum Hall effect;
Pseudo-superconductivity)


title: Fractal Analysis of Discharge Current Fluctuations

abstract:
  We use the multifractal detrended fluctuation analysis (MF-DFA) to study the
electrical discharge current fluctuations in plasma and show that it has
multifractal properties and behaves as a weak anti-correlated process.
Comparison of the MF-DFA results for the original series with those for the
shuffled and surrogate series shows that correlation of the fluctuations is
responsible for multifractal nature of the electrical discharge current.


title: Detection of Acetylene toward Cepheus A East with Spitzer

abstract:
  The first map of interstellar acetylene (C2H2) has been obtained with the
infrared spectrograph onboard the Spitzer Space Telescope. A spectral line map
of the $\nu_5$ vibration-rotation band at 13.7 microns carried out toward the
star-forming region Cepheus A East, shows that the C2H2 emission peaks in a few
localized clumps where gas-phase CO2 emission was previously detected with
Spitzer. The distribution of excitation temperatures derived from fits to the
C2H2 line profiles ranges from 50 to 200 K, a range consistent with that
derived for gaseous CO2 suggesting that both molecules probe the same warm gas
component. The C2H2 molecules are excited via radiative pumping by 13.7 microns
continuum photons emanating from the HW2 protostellar region. We derive column
densities ranging from a few x 10^13 to ~ 7 x 10^14 cm^-2, corresponding to
C2H2 abundances of 1 x 10^-9 to 4 x 10^-8 with respect to H2. The spatial
distribution of the C2H2 emission along with a roughly constant N(C2H2)/N(CO2)
strongly suggest an association with shock activity, most likely the result of
the sputtering of acetylene in icy grain mantles.


title: A(4) Symmetry and Neutrinos

abstract:
  I recount briefly the history of neutrino tribimaximal mixing and the use of
the discrete family symmetry A(4) in obtaining it.


title:
Quantum Antiferromagnetism of Fermions in Optical Lattices with
  Half-filled p-band

abstract:
  We study Fermi gases in a three-dimensional optical lattice with five
fermions per site, i.e. the s-band is completely filled and the p-band with
three-fold degeneracy is half filled. We show that, for repulsive interaction
between fermions, the system will exhibit spin-3/2 antiferromagnetic order at
low temperature. This conclusion is obtained in strong interaction regime by
strong coupling expansion which yields an isotropic spin-3/2 Heisenberg model,
and also in weak interaction regime by Hatree-Fock mean-field theory and
analysis of Fermi surface nesting. We show that the critical temperature for
this antiferromagnetism of a p-band Mott insulator is about two orders of
magnitudes higher than that of an $s$-band Mott insulator, which is close to
the lowest temperature attainable nowadays.


title: Hopf modules for autonomous pseudomonoids and the monoidal centre

abstract:
  In this work we develop some aspects of the theory of Hopf algebras to the
context of autonomous map pseudomonoids. We concentrate in the Hopf modules and
the Centre or Drinfel'd double. If $A$ is a map pseudomonoid in a monoidal
bicategory \M, the analogue of the category of Hopf modules for $A$ is an
Eilenberg-Moore construction for a certain monad in
$\mathbf{Hom}(\M^{\mathrm{op}},\mathbf{Cat})$. We study the existence of the
internalisation of this notion, called the Hopf module construction, by
extending the completion under Eilenberg-Moore objects of a 2-category to a
endo-homomorphism of tricategories on $\mathbf{Bicat}$.
  Our main result is the equivalence between the existence of a left
dualization for $A$ ({\em i.e.}, $A$ is left autonomous) and the validity of an
analogue of the structure theorem of Hopf modules. In this case the Hopf module
construction for $A$ always exists.
  We use these results to study the lax centre of a left autonomous map
pseudomonoid. We show that the lax centre is the Eilenberg-Moore construction
for a certain monad on $A$ (one existing if the other does). If $A$ is also
right autonomous, then the lax centre equals the centre. We look at the
examples of the bicategories of \V-modules and of comodules in \V, and obtain
the Drinfel'd double of a coquasi-Hopf algebra $H$ as the centre of $H$.


title:
Models for the Observable System Parameters of Ultraluminous X-ray
  Sources

abstract:
  We investigate the evolution of the properties of model populations of
ultraluminous X-ray sources (ULXs) consisting of a black-hole accretor in a
binary with a donor star. We have computed models corresponding to three
different populations of black-hole binaries; two invoke stellar-mass (~10
Msun) black hole accretors, and the third utilizes intermediate-mass (~1000
Msun) black holes (IMBHs). For each of the three populations, we computed
30,000 binary evolution sequences using a full Henyey stellar evolution code.
The optical flux from the model ULXs includes contributions from the accretion
disk, due to x-ray irradiation as well as intrinsic viscous heating, and that
due to the donor star. We present "probability images" for the ULX systems in
planes of color-magnitude, orbital period vs. X-ray luminosity, and luminosity
vs. evolution time. Estimates of the numbers of ULXs in a typical galaxy as
functions of time and of X-ray luminosity are also presented. Our model CMDs
are compared with six ULX counterparts that have been discussed in the
literature. Overall, the observed systems seem more closely related to model
systems with very high-mass donors (> ~25 Msun) in binaries with IMBH
accretors. However, significant difficulties remain with both the IMBH and
stellar-mass black hole models.


title: Extraction of Singlet States from Noninteracting High-Dimensional Spins

abstract:
  We present a scheme for the extraction of singlet states of two remote
particles of arbitrary quantum spin number. The goal is achieved through
post-selection of the state of interaction mediators sent in succession. A
small number of iterations is sufficient to make the scheme effective. We
propose two suitable experimental setups where the protocol can be implemented.


title: The Lattice Free Energy of QCD with Clover Fermions, up to Three-Loops

abstract:
  We calculate the perturbative value of the free energy in Lattice QCD, up to
three loops. Our calculation is performed using Wilson gluons and the
Sheikholeslami - Wolhert (clover) improved action for fermions.
  The free energy is directly related to the average plaquette. To carry out
the calculation, we compute all relevant Feynman diagrams up to 3 loops, using
a set of automated procedures in Mathematica; numerical evaluation of the
resulting loop integrals is performed on finite lattice, with subsequent
extrapolation to infinite size.
  The results are presented as a function of the fermion mass m, for any
SU(N_c) gauge group, and for an arbitrary number of fermion flavors. In order
to enable independent comparisons, we also provide the results on a per diagram
basis, for a specific mass value.


title: Generalizations of Sch\"{o}bi's Tetrahedral Dissection

abstract:
  Let v_1, ..., v_n be unit vectors in R^n such that v_i . v_j = -w for i != j,
where -1 <w < 1/(n-1). The points Sum_{i=1..n} lambda_i v_i, where 1 >=
lambda_1 >= ... >= lambda_n >= 0, form a ``Hill-simplex of the first type'',
denoted by Q_n(w). It was shown by Hadwiger in 1951 that Q_n(w) is
equidissectable with a cube. In 1985, Sch\"{o}bi gave a three-piece dissection
of Q_3(w) into a triangular prism c Q_2(1/2) X I, where I denotes an interval
and c = sqrt{2(w+1)/3}. The present paper generalizes Sch\"{o}bi's dissection
to an n-piece dissection of Q_n(w) into a prism c Q_{n-1}(1/(n-1)) X I, where c
= sqrt{(n-1)(w+1)/n}. Iterating this process leads to a dissection of Q_n(w)
into an n-dimensional rectangular parallelepiped (or ``brick'') using at most
n! pieces. The complexity of computing the map from Q_n(w) to the brick is
O(n^2). A second generalization of Sch\"{o}bi's dissection is given which
applies specifically in R^4. The results have applications to source coding and
to constant-weight binary codes.


title: Tamagawa defect of Euler systems

abstract:
  As remarked in [Kolyvagin systems, by Barry Mazur and Karl Rubin] Proposition
6.2.6 and Buyukboduk[ arXiv:0706.0377v1 ] Remark 3.25 one does not expect the
Kolyvagin system obtained from an Euler system for a p-adic Galois
representation T to be primitive (in the sense of [Kolyvagin systems, by Barry
Mazur and Karl Rubin] Definition 4.5.5) if p divides a Tamagawa number at a
prime \ell different from p; thus fails to compute the correct size of the
relevant Selmer module. In this paper we obtain a lower bound for the size of
the cokernel of the Euler system to Kolyvagin system map (see Theorem 3.2.4 of
[Kolyvagin systems, by Barry Mazur and Karl Rubin] for a definition of this
map) in terms of the Tamagawa numbers of T, refining [Kolyvagin systems, by
Barry Mazur and Karl Rubin] Propostion 6.2.6. We show how this partially
accounts for the missing Tamagawa factors in Kato's calculations with his Euler
system.