title:
Velocity-selective sublevel resonance of atoms with an array of
  current-carrying wires

abstract:
  Resonance transitions between the Zeeman sublevels of optically-polarized Rb
atoms traveling through a spatially periodic magnetic field are investigated in
a radio-frequency (rf) range of sub-MHz. The atomic motion induces the
resonance when the Zeeman splitting is equal to the frequency at which the
moving atoms feel the magnetic field oscillating. Additional temporal
oscillation of the spatially periodic field splits a motion-induced resonance
peak into two by an amount of this oscillation frequency. At higher oscillation
frequencies, it is more suitable to consider that the resonance is mainly
driven by the temporal field oscillation, with its velocity-dependence or
Doppler shift caused by the atomic motion through the periodic field. A
theoretical description of motion-induced resonance is also given, with
emphasis on the translational energy change associated with the internal
transition.


title:
An open question: Are topological arguments helpful in setting initial
  conditions for transport problems and quantization criteria/ quantum
  computing for Density Wave physics?

abstract:
  We present derived I-E curves that match Zenier curves used to fit data
experimentally with wavefunctionals congruent with the false vacuum hypothesis.
The open question is whether the coefficients picked in both the
wavefunctionals and the magnitude of the coefficients of the driven sine Gordon
physical system should be picked by topological charge arguments that in
principle appear to assign values that have a tie in with the false vacuum
hypothesis first presented by Sidney Coleman. Our supposition is that indeed
this is useful and that the topological arguments give evidence as to a first
order phase transition which gives credence to the observed and calculated I-E
curve as evidence of a quantum switching phenomena in density wave physics, one
which we think with further development would have applications to quantum
computing, via quantum coherent phase evolution, as outlined in this paper .
This analysis is enhanced by a new phi to the fourth power field theory
treatment of how to model field theory in real time evolution as given to the
Author by Dr. Fred Cooper as part of a meeting in KITP, UCSB in early 2008


title:
High accuracy, absolute, cryogenic refractive index measurements of
  infrared lens materials for JWST NIRCam using CHARMS

abstract:
  The refractive optical design of the James Webb Space Telescope (JWST) Near
Infrared Camera (NIRCam) uses three infrared materials in its lenses: LiF,
BaF2, and ZnSe. In order to provide the instrument's optical designers with
accurate, heretofore unavailable data for absolute refractive index based on
actual cryogenic measurements, two prismatic samples of each material were
measured using the cryogenic, high accuracy, refraction measuring system
(CHARMS) at NASA's Goddard Space Flight Center (GSFC), densely covering the
temperature range from 15 to 320 K and wavelength range from 0.4 to 5.6
microns. Data reduction methods are discussed and graphical and tabulated data
for absolute refractive index, dispersion, and thermo-optic coefficient for
these three materials are presented for selected wavelengths and temperatures
along with estimates of index uncertainty. Coefficients for
temperature-dependent Sellmeier fits of measured index are also presented with
an example of their usage to predict absolute index at any wavelength or
temperature within the applicable range of those parameters.


title:
Temperature-dependent absolute refractive index measurements of
  synthetic fused silica

abstract:
  Using the Cryogenic, High-Accuracy Refraction Measuring System (CHARMS) at
NASA's Goddard Space Flight Center, we have measured the absolute refractive
index of five specimens taken from a very large boule of Corning 7980 fused
silica from temperatures ranging from 30 to 310 K at wavelengths from 0.4 to
2.6 microns with an absolute uncertainty of +/-1 x 10^-5. Statistical
variations in derived values of the thermo-optic coefficient (dn/dT) are at the
+/-2 x 10^-8/K level. Graphical and tabulated data for absolute refractive
index, dispersion, and thermo-optic coefficient are presented for selected
wavelengths and temperatures along with estimates of uncertainty in index.
Coefficients for temperature-dependent Sellmeier fits of measured refractive
index are also presented to allow accurate interpolation of index to other
wavelengths and temperatures. We compare our results to those from an
independent investigation (which used an interferometric technique for
measuring index changes as a function of temperature) whose samples were
prepared from the same slugs of material from which our prisms were prepared in
support of the Kepler mission. We also compare our results with sparse
cryogenic index data from measurements of this material from the literature.


title:
Cellular Systems with Full-Duplex Compress-and-Forward Relaying and
  Cooperative Base Stations

abstract:
  In this paper the advantages provided by multicell processing of signals
transmitted by mobile terminals (MTs) which are received via dedicated relay
terminals (RTs) are studied. It is assumed that each RT is capable of
full-duplex operation and receives the transmission of adjacent relay
terminals. Focusing on intra-cell TDMA and non-fading channels, a simplified
relay-aided uplink cellular model based on a model introduced by Wyner is
considered. Assuming a nomadic application in which the RTs are oblivious to
the MTs' codebooks, a form of distributed compress-and-forward (CF) scheme with
decoder side information is employed. The per-cell sum-rate of the CF scheme is
derived and is given as a solution of a simple fixed point equation. This
achievable rate reveals that the CF scheme is able to completely eliminate the
inter-relay interference, and it approaches a ``cut-set-like'' upper bound for
strong RTs transmission power. The CF rate is also shown to surpass the rate of
an amplify-and-forward scheme via numerical calculations for a wide range of
the system parameters.


title: Prescription for Cosmic Information Extraction from Multiple Sky Maps

abstract:
  This paper presents a prescription for distilling the information contained
in the cosmic microwave background radiation from multiple sky maps that also
contain both instrument noise and foreground contaminants. The prescription is
well-suited for cosmological parameter estimation and accounts for
uncertainties in the cosmic microwave background extraction scheme. The
technique is computationally viable at low resolution and may be considered a
natural and significant generalization of the "Internal Linear Combination"
approach to foreground removal. An important potential application is the
analysis of the multi-frequency temperature and polarization data from the
forthcoming Planck satellite.


title: The volume conjecture for augmented knotted trivalent graphs

abstract:
  We propose to generalize the volume conjecture to knotted trivalent graphs
and we prove the conjecture for all augmented knotted trivalent graphs. As a
corollary we find that for any link L there is a link containing L for which
the volume conjecture holds.


title: Entropy Function and AdS(2)/CFT(1) Correspondence

abstract:
  Wald's formula for black hole entropy, applied to extremal black holes, leads
to the entropy function formalism. We manipulate the entropy computed this way
to express it as the logarithm of the ground state degeneracy of a dual quantum
mechanical system. This provides a natural definition of the extremal black
hole entropy in the full quantum theory. Our analysis also clarifies the
relationship between the entropy function formalism and the Euclidean action
formalism.


title: Temperature-dependent refractive index of CaF2 and Infrasil 301

abstract:
  In order to enable high quality lens designs using calcium fluoride (CaF2)
and Heraeus Infrasil 301 (Infrasil) for cryogenic operating temperatures, we
have measured the absolute refractive index of these two materials as a
function of both wavelength and temperature using the Cryogenic, High-Accuracy
Refraction Measuring System (CHARMS) at NASA's Goddard Space Flight Center. For
CaF2, we report absolute refractive index and thermo-optic coefficient (dn/dT)
at temperatures ranging from 25 to 300 K at wavelengths from 0.4 to 5.6
microns, while for Infrasil, we cover temperatures ranging from 35 to 300 K and
wavelengths from 0.4 to 3.6 microns. For CaF2, we compare our index
measurements to measurements of other investigators. For Infrasil, we compare
our measurements to the material manufacturer's data at room temperature and to
cryogenic measurements for fused silica from previous investigations including
one of our own. Finally, we provide temperature-dependent Sellmeier
coefficients based on our measured data to allow accurate interpolation of
index to other wavelengths and temperatures.


title: Beyond MSSM Baryogenesis

abstract:
  Taking the MSSM as an effective low-energy theory, with a cut-off scale of a
few TeV, can make significant modifications to the predictions concerning the
Higgs and stop sectors. We investigate the consequences of such a scenario for
electroweak baryogenesis. We find that the window for MSSM baryogenesis is
extended and, most important, can be made significantly more natural.
Specifically, it is possible to have one stop lighter than the top and the
other significantly lighter than TeV simultaneously with the Higgs mass above
the LEP bound. In addition, various aspects concerning CP violation are
affected. Most notably, it is possible to have dynamical phases in the bubble
walls at tree level, providing CP violating sources for Standard Model
fermions.


title: Strangeness production from SPS to LHC

abstract:
  Global strangeness production in relativistic heavy ion collisions at SPS and
RHIC is reviewed. Special emphasis is put on the comparison with the
statistical model and the canonical suppression mechanism. It is shown that
recent RHIC data on strange particle production as a function of centrality can
be explained by a superposition of a fully equilibrated hadron gas and particle
emission from single independent nucleon-nucleon collisions in the outer
corona.


title: Analysis of SM quantum information

abstract:
  Morozova and Chentsov (Morozova and Chentsov 90) studied Riemannian metrics
on the set of probability measures. They showed that, up to a constant factor,
the Fisher information is the only Riemannian metric which is monotone under
stochastic transformation. Sarovar and Milburn (Sarovar and Milburn 06)
computed an upper bound on the Fisher information for one-parameter channels.
In (O'Loan 07) we extended their bound to an upper bound on the Fisher
information of multi-parameter families of states; we call this the SM quantum
information. Petz and Sud\'ar (Petz 95) characterized fully the set of monotone
metrics on the space of all density matrices. We analyse the SM quantum
information in light of their work. We show that the SM quantum information is
not a well-defined metric on the space of density matrices: different choices
of phase of the eigenvectors lead to different metrics. We define a new metric
C_L as a lower bound among the SM quantum informations. We look at properties
of C_L and show that it is invariant but not monotone.


title:
Basic Mechanics of Planet-Satellite Interaction with special reference
  to Earth-Moon System

abstract:
  In1879 George Howard Darwin theoretically analyzed the outward spiraling
orbit of Moon and the subsequent lengthening of the Mean Solar Day. The author
redid the same analysis based on the fact that Moon was receding at the rate of
3.8 cm per annum. Basic Mechanics of Earth-Moon is worked out and various
system parameters are optimized to fit the given boundary condition obtained by
Apollo Mission and other modern means of observations. Based on this
theoretical formulation the theoretical graph of the lengthening of the Mean
Solar Day with respect to time is drawn and is compared with the observational
graph of the same based on pale ontological data, paleo tidal data and
iron-banded formation. The observational data on Mean Solar Day is found to
follow the theoretical smooth curve in post-Cambrian Era but is found to
deviate in the remote past. This deviation is corrected by taking the evolving
form of Moment of Inertia of Earth. The deviation of the observed data prompts
the Author to suggest that the lengthening of the Mean Solar Day curve could
possibly be used as an analytical seismograph for the impending earthquakes and
sudden volcanic eruptions. The Basic Mechanics of E-M system is generalized to
lay the foundation of simulation software for any Planet-Satellite pair in our
Solar System.


title:
Multiresolution analysis of active region magnetic structure and its
  correlation with the Mt. Wilson classification and flaring activity

abstract:
  Two different multi-resolution analyses are used to decompose the structure
of active region magnetic flux into concentrations of different size scales.
Lines separating these opposite polarity regions of flux at each size scale are
found. These lines are used as a mask on a map of the magnetic field gradient
to sample the local gradient between opposite polarity regions of given scale
sizes. It is shown that the maximum, average and standard deviation of the
magnetic flux gradient for alpha, beta, beta-gamma and beta-gamma-delta active
regions increase in the order listed, and that the order is maintained over all
length-scales. This study demonstrates that, on average, the Mt. Wilson
classification encodes the notion of activity over all length-scales in the
active region, and not just those length-scales at which the strongest flux
gradients are found. Further, it is also shown that the average gradients in
the field, and the average length-scale at which they occur, also increase in
the same order. Finally, there are significant differences in the gradient
distribution, between flaring and non-flaring active regions, which are
maintained over all length-scales. It is also shown that the average gradient
content of active regions that have large flares (GOES class 'M' and above) is
larger than that for active regions containing flares of all flare sizes; this
difference is also maintained at all length-scales.


title: Resonant speed meter for gravitational wave detection

abstract:
  Gravitational-wave detectors have been well developed and operated with high
sensitivity. However, they still suffer from mirror displacement noise. In this
paper, we propose a resonant speed meter, as a displacement noise-canceled
configuration based on a ring-shaped synchronous recycling interferometer. The
remarkable feature of this interferometer is that, at certain frequencies,
gravitational-wave signals are amplified, while displacement noises are not.


title: Note on the ring approximation in nuclear matter

abstract:
  The response function to an external prove is evaluated using the ring
approximation in nuclear matter. Contrary to what it is usually assumed, it is
shown that the summation of the ring series and the solution of the Dyson's
equation are two different approaches. The numerical results exhibit a
perceptible difference between both approximations.


title:
Cosmic Rays Above the Second Knee from Clusters of Galaxies and
  Associated High-Energy Neutrino Emission

abstract:
  Accretion and merger shocks in clusters of galaxies are potential
accelerators of high-energy protons, which can give rise to high-energy
neutrinos through pp interactions with the intracluster gas. We discuss the
possibility that protons from cluster shocks make a significant contribution to
the observed cosmic rays in the energy range between the second knee around
10^17.5 eV and the ankle around 10^18.5 eV. The accompanying cumulative
neutrino background above PeV may be detectable by upcoming neutrino telescopes
such as IceCube or KM3NeT, providing a test of this scenario as well as a probe
of cosmic-ray confinement properties in clusters.


title: Interference of Bose-Einstein condensates: quantum non-local effects

abstract:
  Quantum systems in Fock states do not have a phase. When two or more
Bose-Einstein condensates are sent into interferometers, they nevertheless
acquire a relative phase under the effect of quantum measurements. The usual
explanation relies on spontaneous symmetry breaking, where phases are ascribed
to all condensates and treated as unknown classical quantities. However, this
image is not always sufficient: when all particles are measured, quantum
mechanics predicts probabilities that are sometimes in contradiction with it,
as illustrated by quantum violations of local realism. In this letter, we show
that interferometers can be used to demonstrate a large variety of violations
with an arbitrarily large number of particles. With two independent
condensates, we find violations of the BCHSH inequalities, as well as new
N-body Hardy impossibilities. With three condensates, we obtain new GHZ
(Greenberger, Horne and Zeilinger) type contradictions.


title: Resonances for a diffusion with small noise

abstract:
  We study resonances for the generator of a diffusion with small noise in
$R^d$ :$ L_\epsilon = -\epsilon\Delta + \nabla F \cdot \nabla$, when the
potential F grows slowly at infinity (typically as a square root of the norm).
The case when F grows fast is well known, and under suitable conditions one can
show that there exists a family of exponentially small eigenvalues, related to
the wells of F . We show that, for an F with a slow growth, the spectrum is R+,
but we can find a family of resonances whose real parts behave as the
eigenvalues of the "quick growth" case, and whose imaginary parts are small.


title: Bilinear Hilbert transforms along curves I. The monomial case

abstract:
  We establish an L^2 \times L^2 to L^1 estimate for the bilinear Hilbert
transform along a curve defined by a monomial. Our proof is closely related to
multi-linear oscillatory integrals.


title: The Gaussian Wiretap Channel with a Helping Interferer

abstract:
  Due to the broadcast nature of the wireless medium, wireless communication is
susceptible to adversarial eavesdropping. This paper describes how
eavesdropping can potentially be defeated by exploiting the superposition
nature of the wireless medium. A Gaussian wire-tap channel with a helping
interferer (WTC-HI) is considered in which a transmitter sends confidential
messages to its intended receiver in the presence of a passive eavesdropper and
with the help of an interferer. The interferer, which does not know the
confidential message assists the confidential message transmission by sending a
signal that is independent of the transmitted message. An achievable secrecy
rate and a Sato-type upper bound on the secrecy capacity are given for the
Gaussian WTC-HI. Through numerical analysis, it is found that the upper bound
is close to the achievable secrecy rate when the interference is weak for
symmetric interference channels, and under more general conditions for
asymmetric Gaussian interference channels.


title: Generalizations of Han's Hook Length Identities

abstract:
  Han recently discovered new hook length identities for binary trees. In this
paper, we extend Han's identities to binomial families of trees. Moreover, we
present a bijective proof of one of the identities for the family of ordered
trees.


title:
A mathematical model of turbulent drag reduction by
  high-molecular-weight polymeric additives in a shear flow

abstract:
  Drag reduction, or, what is the same, mean velocity increase in a turbulent
flow at a fixed pressure drop through the addition of tiny amounts (several
parts per million) of high molecular weight polymers (Thoms effect), is known
already for more than sixty years. Rather long ago it was understood that this
effect is related to supramolecular structures formed in the flow. Recent
experiments by S. Chu, E.S.G. Shaqfeh and their associates, where the motion of
supramolecular structures was directly observed, made it possible to understand
and quantify the dynamic interaction of the polymeric structures with the
solvent (water) flow. These results lead to the construction of a mathematical
model of the Thoms effect, based on the Kolmogorov(1942)-Prandtl(1945)
semi-empirical theory of shear flow turbulence.


title: Kummer surfaces associated to (1,2)-polarized abelian surfaces

abstract:
  The aim of this paper is to describe the geometry of the generic Kummer
surface associated to a $(1,2)$-polarized abelian surface. We show that it is
the double cover of a weak del Pezzo surface and that it inherits from the del
Pezzo surface an elliptic fibration with twelve singular fibers of type $I_2.$


title: Diffusive Transport in Periodic Potentials: Underdamped Dynamics

abstract:
  In this paper we present a systematic and rigorous method for calculating the
diffusion tensor for a Brownian particle moving in a periodic potential which
is valid in arbitrary dimensions and for all values of the dissipation. We use
this method to obtain an explicit formula for the diffusion coefficient in one
dimension which is valid in the underdamped limit, and we also obtain higher
order corrections to the Lifson-Jackson formula for the diffusion coefficient
in the overdamped limit. A numerical method for calculating the diffusion
coefficient is also developed and is shown to perform extremely well for all
values of the dissipation.


title:
New strings for old Veneziano amplitudes IV.Connections with spin chains
  and other stochastic systems

abstract:
  In a series of published papers we reanalyzed treatments of the Veneziano
amplitudes and the models associated with them. In this work we demonstrate
that the already obtained partition function for these amplitudes can be
exactly mapped into that for the Polychronakos-Frahm spin chain which, in turn,
is obtainable from the Richardson-Gaudin XXX model. Reshetikhin and Varchenko
demonstrated that such a model is recoverable from their WKB-type analysis of
solutions of the Knizhnik-Zamolodchikov (K-Z) equations. The linear
independence of solutions of these equations is controlled by determinants
whose form (up to a constant) coincides with the Veneziano (or Veneziano-like)
amplitudes.In the simplest case, when the K-Z equations are reducible to the
Gauss hypergeometric equation, the determinantal conditions coincide with those
which were discovered by Kummer in 19th century. Kummer's results admit
physical interpretation crucial for providing needed justification associating
determinanatal formula(s) with Veneziano-like amplitudes. General results are
illustrated by many examples. These include but are not limited to only high
energy physics since all high energy physics scattering processes can be looked
upon from much broader sctochastic theory of random fragmentation and
coagulation processes recently undergoing active development in view of its
applications in disciplines ranging from ordering in spin glasses and
population genetics to computer science, linguistics and economics,etc. In this
theory Veneziano amplitudes play the universal role since they are the
Poisson-Dirichlet-type distributions for these processes (analogous to the more
familiar Maxwell distribution for gases)


title: Where does Cosmological Perturbation Theory Break Down?

abstract:
  We apply the effective field theory approach to the coupled metric-inflaton
system, in order to investigate the impact of higher dimension operators on the
spectrum of scalar and tensor perturbations in the short-wavelength regime. In
both cases, effective corrections at tree-level become important when the
Hubble parameter is of the order of the Planck mass, or when the physical wave
number of a cosmological perturbation mode approaches the square of the Planck
mass divided by the Hubble constant. Thus, the cut-off length below which
conventional cosmological perturbation theory does not apply is likely to be
much smaller than the Planck length. This has implications for the
observability of "trans-Planckian" effects in the spectrum of primordial
perturbations.


title: Binary Star Origin of High Field Magnetic White Dwarfs

abstract:
  White dwarfs with surface magnetic fields in excess of $1 $MG are found as
isolated single stars and relatively more often in magnetic cataclysmic
variables. Some 1,253 white dwarfs with a detached low-mass main-sequence
companion are identified in the Sloan Digital Sky Survey but none of these is
observed to show evidence for Zeeman splitting of hydrogen lines associated
with a magnetic field in excess of 1MG. If such high magnetic fields on white
dwarfs result from the isolated evolution of a single star then there should be
the same fraction of high field white dwarfs among this SDSS binary sample as
among single stars. Thus we deduce that the origin of such high magnetic fields
must be intimately tied to the formation of cataclysmic variables. CVs emerge
from common envelope evolution as very close but detached binary stars that are
then brought together by magnetic braking or gravitational radiation. We
propose that the smaller the orbital separation at the end of the common
envelope phase, the stronger the magnetic field. The magnetic cataclysmic
variables originate from those common envelope systems that almost merge. We
propose further that those common envelope systems that do merge are the
progenitors of the single high field white dwarfs. Thus all highly magnetic
white dwarfs, be they single stars or the components of MCVs, have a binary
origin. This hypothesis also accounts for the relative dearth of single white
dwarfs with fields of 10,000 - 1,000,000G. Such intermediate-field white dwarfs
are found preferentially in cataclysmic variables. In addition the bias towards
higher masses for highly magnetic white dwarfs is expected if a fraction of
these form when two degenerate cores merge in a common envelope. Similar
scenarios may account for very high field neutron stars.


title:
Philosophy of mind and the problem of free will in the light of quantum
  mechanics

abstract:
  Defects occasioned by the advent of quantum mechanics are described in detail
of recent arguments by John Searle and by Jaegwon Kim pertaining to the
question of the complete reducibility to the physical of the apparent capacity
of a person's conscious thoughts to affect the behaviour of that person's
physically described brain.


title: Non-linear structure formation and the acoustic scale

abstract:
  We present high signal-to-noise measurements of the acoustic scale in the
presence of nonlinear growth and redshift distortions using 320(Gpc/h)^3 of
cosmological PM simulations. Using simple fitting methods, we obtain robust
measurements of the acoustic scale with scatter close to that predicted by the
Fisher matrix. We detect and quantify the shift in the acoustic scale by
analyzing the power spectrum: we detect at greater than 5 sigma a decrease in
the acoustic scale in the real-space matter power spectrum of 0.2% at z=1.5,
growing to 0.45% at z=0.3. In redshift space, the shifts are about 25% larger:
we detect a decrease of 0.25% of at z=1.5 and 0.54% at z=0.3. Despite the
nonzero amounts, these shifts are highly predictable numerically, and hence
removable within the standard ruler analysis of clustering data. Moreover, we
show that a simple density-field reconstruction method substantially reduces
the scatter and nonlinear shifts of the acoustic scale measurements: the shifts
are reduced to less than 0.1% at z=0.3-1.5, even in the presence of
non-negligible shot noise. Finally, we show that the ratio of the cosmological
distance to the sound horizon that would be inferred from these fits is robust
to variations in the parameterization of the fitting method and reasonable
differences in the template cosmology.


title:
The effect of noise on a hyperbolic strange attractor in the system of
  two coupled van der Pol oscillators

abstract:
  We study the effect of noise for a physically realizable flow system with a
hyperbolic chaotic attractor of the Smale - Williams type in the Poincare
cross-section [S.P. Kuznetsov, Phys. Rev. Lett. 95, 2005, 144101]. It is shown
numerically that slightly varying the initial conditions on the attractor one
can obtain a uniform approximation of a noisy orbit by the trajectory of the
system without noise, that is called as the "shadowing" trajectory. We propose
an algorithm for locating the shadowing trajectories in the system under
consideration. Using this algorithm, we show that the mean distance between a
noisy orbit and the approximating one does not depend essentially on the length
of the time interval of observation, but only on the noise intensity. This
dependance is nearly linear in a wide interval of the intensities of noise. It
is found out that for weak noise the Lyapunov exponents do not depend
noticeably on the noise intensity. However, in the case of a strong noise the
largest Lyapunov exponent decreases and even becomes negative indicating the
suppression of chaos by the external noise.


title: Del Pezzo Surfaces of degree 6 over an arbitrary field

abstract:
  We give a characterization of all del Pezzo surfaces of degree 6 over an
arbitrary field $F$. A surface is determined by a pair of separable algebras.
These algebras are used to compute the Quillen $K$-theory of the surface. As a
consequence, we obtain an index reduction formula for the function field of the
surface.


title: Nonnegative Matrix Factorization via Rank-One Downdate

abstract:
  Nonnegative matrix factorization (NMF) was popularized as a tool for data
mining by Lee and Seung in 1999. NMF attempts to approximate a matrix with
nonnegative entries by a product of two low-rank matrices, also with
nonnegative entries. We propose an algorithm called rank-one downdate (R1D) for
computing a NMF that is partly motivated by singular value decomposition. This
algorithm computes the dominant singular values and vectors of adaptively
determined submatrices of a matrix. On each iteration, R1D extracts a rank-one
submatrix from the dataset according to an objective function. We establish a
theoretical result that maximizing this objective function corresponds to
correctly classifying articles in a nearly separable corpus. We also provide
computational experiments showing the success of this method in identifying
features in realistic datasets.


title: Theory and modeling of particles with DNA-mediated interactions

abstract:
  In recent years significant attention has been attracted to proposals which
utilize DNA for nanotechnological applications. Potential applications of these
ideas range from the programmable self-assembly of colloidal crystals, to
biosensors and nanoparticle based drug delivery platforms. In Chapter I we
introduce the system, which generically consists of colloidal particles
functionalized with specially designed DNA markers. The sequence of bases on
the DNA markers determines the particle type. Due to the hybridization between
complementary single-stranded DNA, specific, type-dependent interactions can be
introduced between particles by choosing the appropriate DNA marker sequences.
In Chapter II we develop a statistical mechanical description of the
aggregation and melting behavior of particles with DNA-mediated interactions.
In Chapter III a model is proposed to describe the dynamical departure and
diffusion of particles which form reversible key-lock connections. In Chapter
IV we propose a method to self-assemble nanoparticle clusters using DNA
scaffolds. A natural extension is discussed in Chapter V, the programmable
self-assembly of nanoparticle clusters where the desired cluster geometry is
encoded using DNA-mediated interactions. In Chapter VI we consider a
nanoparticle based drug delivery platform for targeted, cell specific
chemotherapy. In Chapter VII we present prospects for future research: the
connection between DNA-mediated colloidal crystallization and jamming, and the
inverse problem in self-assembly.


title: Optimal Robust Mean-Variance Hedging in Incomplete Financial Markets

abstract:
  Optimal B-robust estimate is constructed for multidimensional parameter in
drift coefficient of diffusion type process with small noise. Optimal
mean-variance robust (optimal V -robust) trading strategy is find to hedge in
mean-variance sense the contingent claim in incomplete financial market with
arbitrary information structure and misspecified volatility of asset price,
which is modelled by multidimensional continuous semimartingale. Obtained
results are applied to stochastic volatility model, where the model of latent
volatility process contains unknown multidimensional parameter in drift
coefficient and small parameter in diffusion term.

categories: q-fin.PM math.PR math.ST stat.AP stat.TH


title:
Study of the effects induced by lead on the emulsion films of the OPERA
  experiment

abstract:
  The OPERA neutrino oscillation experiment is based on the use of the Emulsion
Cloud Chamber (ECC). In the OPERA ECC, nuclear emulsion films acting as very
high precision tracking detectors are interleaved with lead plates providing a
massive target for neutrino interactions. We report on studies related to the
effects occurring from the contact between emulsion and lead. A low
radioactivity lead is required in order to minimize the number of background
tracks in emulsions and to achieve the required performance in the
reconstruction of neutrino events. It was observed that adding other chemical
elements to the lead, in order to improve the mechanical properties, may
significantly increase the level of radioactivity on the emulsions. A detailed
study was made in order to choose a lead alloy with good mechanical properties
and an appropriate packing technique so as to have a low enough effective
radioactivity.


title: Dark matter annihilation in the gravitational field of a black hole

abstract:
  In this paper we consider dark matter particle annihilation in the
gravitational field of black holes. We obtain exact distribution function of
the infalling dark matter particles, and compute the resulting flux and spectra
of gamma rays coming from the objects. It is shown that the dark matter density
significantly increases near a black hole. Particle collision energy becomes
very high affecting relative cross-sections of various annihilation channels.
We also discuss possible experimental consequences of these effects.


title:
Unjamming due to local perturbations in granular packings with and
  without gravity

abstract:
  We investigate the unjamming response of disordered packings of frictional
hard disks with the help of computer simulations. First, we generate jammed
configurations of the disks and then force them to move again by local
perturbations. We study the spatial distribution of the stress and displacement
response and find long range effects of the perturbation in both cases. We
record the penetration depth of the displacements and the critical force that
is needed to make the system yield. These quantities are tested in two types of
systems: in ideal homogeneous packings in zero gravity and in packings settled
under gravity. The penetration depth and the critical force are sensitive to
the interparticle friction coefficient. Qualitatively, the same nonmonotonic
friction dependence is found both with and without gravity, however the
location of the extrema are at different friction values. We discuss the role
of the connectivity of the contact network and of the pressure gradient in the
unjamming response.


title:
Solid superheating observed in two-dimensional strongly-coupled dusty
  plasma

abstract:
  It is demonstrated experimentally that strongly-coupled plasma exhibits solid
superheating. A 2D suspension of microspheres in dusty plasma, initially
self-organized in a solid lattice, was heated and then cooled rapidly by
turning laser heating on and off. Particles were tracked using video
microscopy, allowing atomistic-scale observation during melting and
solidification. During rapid heating, the suspension remained in a solid
structure at temperatures above the melting point, demonstrating solid
superheating. Hysteresis diagrams did not indicate liquid supercooling in this
2D system.


title:
A generalised Joyce construction for a family of nonlinear partial
  differential equations

abstract:
  We explain a simple construction of solutions to a family of PDE's in two
dimensions which includes that defining zero scalar curvature Kahler metrics,
with two Killing fields, and the affine maximal equation.


title: Constant scalar curvature metrics on toric surfaces

abstract:
  This paper completes a programme to determine which toric surfaces admit
Kahler metrics of constant scalar curvature/


title: On some entropy functionals derived from R\'enyi information divergence

abstract:
  We consider the maximum entropy problems associated with R\'enyi $Q$-entropy,
subject to two kinds of constraints on expected values. The constraints
considered are a constraint on the standard expectation, and a constraint on
the generalized expectation as encountered in nonextensive statistics. The
optimum maximum entropy probability distributions, which can exhibit a
power-law behaviour, are derived and characterized. The R\'enyi entropy of the
optimum distributions can be viewed as a function of the constraint. This
defines two families of entropy functionals in the space of possible expected
values. General properties of these functionals, including nonnegativity,
minimum, convexity, are documented. Their relationships as well as numerical
aspects are also discussed. Finally, we work out some specific cases for the
reference measure $Q(x)$ and recover in a limit case some well-known entropies.


title:
On statements of experimental results expressed in the mathematical
  language of quantum theory

abstract:
  We note the separation of a quantum description of an experiment into a
statement of results (as probabilities) and an explanation of these results (in
terms of linear operators). The inverse problem of choosing an explanation to
fit given results is analyzed, leading to the conclusion that any quantum
description comes as an element of a family of related descriptions, entailing
multiple statements of results and multiple explanations. Facing this
multiplicity opens avenues for exploration and consequences that are only
beginning to be explored. Among the consequences are these: (1) statements of
results impose topologies on control parameters, without resort to any quantum
explanation; (2) an endless source of distinct explanations forces an open
cycle of exploration and description bringing more and more control parameters
into play, and (3) ambiguity of description is essential to the concept of
invariance in physics.


title:
Diversity-Multiplexing Tradeoff in Selective-Fading Multiple-Access MIMO
  Channels

abstract:
  We establish the optimal diversity-multiplexing (DM) tradeoff of coherent
selective-fading multiple-access multiple-input multiple-output (MIMO) channels
and provide corresponding code design criteria. As a byproduct, on the
conceptual level, we find an interesting relation between the DM tradeoff
framework and the notion of dominant error event regions which was first
introduced in the AWGN case by Gallager, IEEE Trans. IT, 1985. This relation
allows to accurately characterize the error mechanisms in MIMO fading
multiple-access channels. In particular, we find that, for a given rate tuple,
the maximum achievable diversity order is determined by the error event that
dominates the total error probability exponentially in SNR. Finally, we show
that the distributed space-time code construction proposed recently by Badr and
Belfiore, Int. Zurich Seminar on Commun., 2008, satisfies the code design
criteria derived in this paper.


title:
Numerical study of two-body correlation in a 1D lattice with perfect
  blockade

abstract:
  We compute the dynamics of excitation and two-body correlation for two-level
"pseudoatoms" in a 1D lattice. We adopt a simplified model where pair
excitation within a finite range is perfectly blocked. Each superatom is
initially in the ground state, and then subjected to an external driving laser
with Rabi frequency satisfying a Poissonian distribution, mimicking the
scenario as in Rydberg gases. We find that two-body quantum correlation drops
very fast with the distance between pseudoatoms. However, the total correlation
decays slowly even at large distance. Our results may be useful to the
understanding of Rydberg gases in the strong blockade regime.


title:
Uniform uniform exponential growth of subgroups of the mapping class
  group

abstract:
  Let Mod(S) denote the mapping class group of a compact, orientable surface S.
We prove that finitely generated subgroups of Mod(S) which are not virtually
abelian have uniform exponential growth with minimal growth rate bounded below
by a constant depending only, and necessarily, on S. For the proof, we find in
any such subgroup explicit free group generators which are "short" in any word
metric. Besides bounding growth, this allows a bound on the return probability
of simple random walks.


title: Non-critical string pentagon equations and their solutions

abstract:
  We derive pentagon type relations for the 3-point boundary tachyon
correlation functions in the non-critical open string theory with generic
c_{matter} < 1 and study their solutions in the case of FZZ branes. A new
general formula for the Liouville 3-point factor is derived.


title:
Decoupling of Eulerian and Lagrangia varables in Lagrangian velocity
  correlations

abstract:
  The motion of a particle carried by a liquid is described by the differential
equation equating the velocity of the particle at time t to the the Eulerian
velocity field at time t and at the location of the particle at that time.
Assuming the velocity field to be random with a stationary, isotropic,
translational invariant, zero mean distribution, the Lagrangian velocity
correlation of the particle can be expressed in terms of the Eulerian
correlations and the characteristic function of the probability distribution of
the end point of the trajectory at time t, where the particle is taken to be at
the origin at time 0. This is a result of a decoupling, which is exact to
leading order in the volume of the system.


title: Is loop quantization in cosmology unique?

abstract:
  We re-examine the process of loop quantization for flat isotropic models in
cosmology. In particular, we contrast different inequivalent `loop
quantizations' of these simple models through their respective successes and
limitations and assess whether they can lead to any viable physical
description. We propose three simple requirements which any such admissible
quantum model should satisfy: i) independence from any auxiliary structure,
such as a fiducial interval/cell introduced to define the phase space when
integrating over non-compact manifolds; ii) existence of a well defined
classical limit and iii) provide a sensible "Planck scale" where quantum
gravitational effects become manifest. We show that even when it may seem that
one can have several possible loop quantizations, these physical requirements
considerably narrow down the consistent choices. Apart for the so called
improved dynamics of LQC, none of the other available inequivalent loop
quantizations pass above tests, showing the limitations of lattice refinement
models to approximate the homogeneous sector and loop modified quantum
geometrodynamics. We conclude that amongst a large class of loop quantizations
in isotropic cosmology, there is a unique consistent choice.


title:
The M31 microlensing event WeCAPP-GL1/Point-AGAPE-S3: evidence for a
  MACHO component in the dark halo of M31?

abstract:
  We re-analyze the M31 microlensing event WeCAPP-GL1/Point-AGAPE-S3 taking
into account that stars are not point-like but extended. We show that the
finite size of stars can dramatically change the self-lensing eventrate and
(less dramatically) also the halo lensing eventrate, if events are as bright as
WeCAPP-GL1. The brightness of the brightest events mostly depends on the source
sizes and fluxes and on the distance distribution of sources and lenses and
therefore can be used as a sensitive discriminator between halo-lensing and
self-lensing events, provided the stellar population mix of source stars is
known well enough. Using a realistic model for the 3D-light distribution,
stellar population and extinction of M31, we show that an event like WeCAPP-GL1
is very unlikely to be caused by self-lensing. In the entire WeCAPP-field
($17.2'\times 17.2'$ centered on the bulge) we expect only one self-lensing
event every 49 years with the approximate parameters of WeCAPP-GL1 (time-scale
1-3d, $R$ flux-excess <19.0 mag). If we assume only 20% of the dark halos of
M31 and the Milky-Way consist of 1 solar mass MACHOs an event like WeCAPP-GL1
would occur every 10 years. Further more, if one uses position, FWHM time
scale, flux excess and color of WeCAPP-GL1, self-lensing is even 13 times less
likely than lensing by a MACHO, if MACHOs contribute 20% to the total halo mass
and have masses in the range of 0.1 to 4 solar masses. We also demonstrate that
(i) the brightness distribution of events in general is a good discriminator
between self and halo lensing (ii) the time-scale distribution is a good
discriminator if the MACHO mass is larger than 0.5 solar masses. Future surveys
of M31 like PAndromeda (Pan-STARRS 1) should be able to provide many more such
events within the next 4 years.


title:
X-ray flares, neutrino cooled disks, and the dynamics of late accretion
  in GRB engines

abstract:
  We compute the average luminosity of X-ray flares as a function of time, for
a sample of 10 long-duration gamma-ray burst afterglows. The mean luminosity,
averaged over a timescale longer than the duration of the individual flares,
declines as a power-law in time with index ~-1.5. We elaborate on the
properties of the central engine that can produce such a decline. Assuming that
the engine is an accreting compact object, and for a standard conversion factor
between accretion rate and jet luminosity, the switch between a neutrino-cooled
thin disk and a non-cooled thick disk takes place at the transition from the
prompt to the flaring phase. We discuss the implications of this coincidence
under different scenarios for the powering of the GRB outflow. We also show
that the interaction of the outflow with the envelope of the progenitor star
cannot produce flares out of a continuous relativistic flow, and conclude that
it is the dynamics of the disk or the jet-launching mechanism that generates an
intrinsically unsteady outflow on timescales much longer than the dynamical
timescale of the system. This is consistent with the fact that X-ray flares are
observed in short-duration GRBs as well as in long-duration ones.


title: Weak Gravitational Lensing and its Cosmological Applications

abstract:
  Weak gravitational lensing is a unique probe of the dark side of the
universe: it provides a direct way to map the distribution of dark matter
around galaxies, clusters of galaxies and on cosmological scales. Furthermore,
the measurement of lensing induced distortions of the shapes of distant
galaxies is a powerful probe of dark energy. In this review we describe how
lensing measurements are made and interpreted. We discuss various systematic
effects that can hamper progress and how they may be overcome. We review some
of the recent results in weak lensing by galaxies, galaxy clusters and cosmic
shear and discuss the prospects for dark energy measurements from planned
surveys.


title: Stellar Exotica in 47 Tucanae

abstract:
  We present far-UV spectroscopy obtained with HST for 48 blue objects in the
core of 47 Tuc. Based on their position in a FUV-optical colour-magnitude
diagram, these were expected to include cataclysmic variables (CVs), blue
stragglers (BSs), white dwarfs (WDs) and other exotic objects. For a subset of
these sources, we also construct FUV-NIR SEDs. Based on our analysis of this
extensive data set, we report the following main results. (1) We
spectroscopically confirm 3 previously known or suspected CVs via the detection
of emission lines and find new evidence for dwarf nova eruptions in two of
these. (2) Only one other source in our spectroscopic sample exhibits marginal
evidence for line emission, but predicted and observed CV numbers still agree
to within a factor of about 2-3. (3) We have discovered a hot (T_eff = 8700 K),
low-mass (M = 0.05 M_sun) secondary star in a previously known 0.8 day binary
system. This exotic object is probably the remnant of a subgiant that has been
stripped of its envelope and may represent the ``smoking gun'' of a recent
dynamical encounter. (4) We have found a Helium WD, the second to be optically
detected in 47 Tuc, and the first outside a millisecond-pulsar system. (5) We
have discovered a BS-WD binary system, the first known in any globular cluster.
(6) We have found two additional candidate WD binary systems with putative main
sequence and subgiant companions. (7) We estimate the WD binary fraction in the
core of 47 Tuc to be 15 +17/-9 (stat) +8/-7 (sys). (8) One BS in our sample may
exceed twice the cluster turn-off mass, but the uncertainties are large. Taken
as a whole, our study illustrates the wide range of stellar exotica that are
lurking in the cores of GCs, most of which are likely to have undergone
significant dynamical encounters. [abridged]


title: Cullen-regular quaternionic functions in a Fueter operator framework

abstract:
  We show characterizations of the class of Cullen-regular functions in the
sense of Gentili-Struppa for any domain $\Omega$ in terms of the Fueter
operator. We then state a Integral Theorem and discuss how it can be used to
define a more general version of Cullen-regularity, that does not require the
function to be of class $C^{1}$.


title:
Absence of a consistent classical equation of motion for a
  mass-renormalized point charge

abstract:
  The restrictions of analyticity, relativistic (Born) rigidity, and negligible
O(a) terms involved in the evaluation of the self electromagnetic force on an
extended charged sphere of radius "a" are explicitly revealed and taken into
account in order to obtain a classical equation of motion of the extended
charge that is both causal and conserves momentum-energy. Because the
power-series expansion used in the evaluation of the self force becomes invalid
during transition time intervals immediately following the application and
termination of an otherwise analytic externally applied force, transition
forces must be included during these transition time intervals to remove the
noncausal pre-acceleration and pre-deceleration from the solutions to the
equation of motion without the transition forces. For the extended charged
sphere, the transition forces can be chosen to maintain conservation of
momentum-energy in the causal solutions to the equation of motion within the
restrictions of relativistic rigidity and negligible O(a) terms under which the
equation of motion is derived. However, it is shown that renormalization of the
electrostatic mass to a finite value as the radius of the charge approaches
zero introduces a violation of momentum-energy conservation into the causal
solutions to the equation of motion of the point charge if the magnitude of the
external force becomes too large. That is, the causal classical equation of
motion of a point charge with renormalized mass experiences a high acceleration
catastrophe.


title:
Peak shifts due to $B^{(*)}-\bar{B}^{(*)}$ rescattering in
  $\Upsilon(5S)$ dipion transitions

abstract:
  We study the energy distributions of dipion transitions $\Upsilon(5S)$ to
$\Upsilon(1S,2S,3S)\pi^+\pi^-$ in the final state rescattering model. Since the
$\Upsilon(5S)$ is well above the open bottom thresholds, the dipion transitions
are expected to mainly proceed through the real processes $\Upsilon(5S)\to
B^{(*)}\bar{B}^{(*)}$ and $B^{(*)}\bar{B}^{(*)}\to
\Upsilon(1S,2S,3S)\pi^+\pi^-$. We find that the energy distributions of
$\Upsilon(1S,2S,3S)\pi^+\pi^-$ markedly differ from that of $\Upsilon(5S)\to
B^{(*)}\bar{B}^{(*)}$. In particular, the resonance peak will be pushed up by
about 7-20 MeV for these dipion transitions relative to the main hadronic decay
modes. These predictions can be used to test the final state rescattering
mechanism in hadronic transitions for heavy quarkonia above the open flavor
thresholds.


title: What did we learn from gamma-ray burst 080319B ?

abstract:
  The optical and gamma-ray observations of GRB 080319B allow us to determine a
fairly complete physical picture for this remarkable burst. The data indicate
that the prompt optical and gamma-ray photons were produced at the same
location but by different radiation processes: synchrotron and synchrotron
self-Compton, respectively. The burst emission was produced at a distance of
10^{16.5} cm from the center of explosion by an ultra-relativistic source
moving at Lorentz factor of ~500. A straightforward inference is that about 10
times more energy must have been radiated at tens of GeV than that released at
~1 MeV. Assuming that the GRB outflow was baryonic and that the gamma-ray
source was shock-heated plasma, the collimation-corrected kinetic energy of the
jet powering GRB 080319B was larger than 10^{52.3} erg. The decay of the early
afterglow optical emission (up to 1 ks) is too fast to be attributed to the
reverse shock crossing the GRB ejecta but is consistent with the expectations
for the "large-angle emission" released during the burst. The pure power-law
decay of the optical afterglow flux from 1 ks to 10 day is most naturally
identified with the (synchrotron) emission from the shock propagating into a
wind-like medium. However, the X-ray afterglow requires a departure from the
standard blast-wave model.


title: Grand unification and enhanced quantum gravitational effects

abstract:
  In grand unified theories with large numbers of fields, renormalization
effects significantly modify the scale at which quantum gravity becomes strong.
This in turn can modify the boundary conditions for coupling constant
unification, if higher dimensional operators induced by gravity are taken into
consideration. We show that the generic size of these effects from gravity can
be larger than the two-loop corrections typically considered in renormalization
group analyses of unification. In some cases, gravitational effects of modest
size can render unification impossible.


title:
A simple determination of some characteristics of the beta Pictoris
  system

abstract:
  The aim of this contribution is to determine the lower limit of the electron
number density,the Debye temperature and the specific heat of solid grains
present in the protoplanetary grains around beta Pictoris. The calculation has
been performed using the Salpeter criterion,slightly modified a couple of years
ago. The results obtained are physically reasonable and could be helpful in
determining the chemical composition of solid particles in this system.


title: Chaotic Spin Dynamics of a Long Nanomagnet Driven by a Current

abstract:
  We study the spin dynamics of a long nanomagnet driven by an electrical
current. In the case of only DC current, the spin dynamics has a sophisticated
bifurcation diagram of attractors. One type of attractors is a weak chaos. On
the other hand, in the case of only AC current, the spin dynamics has a rather
simple bifurcation diagram of attractors. That is, for small Gilbert damping,
when the AC current is below a critical value, the attractor is a limit cycle;
above the critical value, the attractor is chaotic (turbulent). For normal
Gilbert damping, the attractor is always a limit cycle in the physically
interesting range of the AC current. We also developed a Melnikov integral
theory for a theoretical prediction on the occurrence of chaos. Our Melnikov
prediction seems performing quite well in the DC case. In the AC case, our
Melnikov prediction seems predicting transient chaos. The sustained chaotic
attractor seems to have extra support from parametric resonance leading to a
turbulent state.


title:
Model for the Magnetic Order and Pairing Channels in Fe Pnictide
  Superconductors

abstract:
  A two-orbital model for Fe-pnictide superconductors is investigated using
computational techniques on two-dimensional square clusters. The hopping
amplitudes are derived from orbital overlap integrals, or by band structure
fits, and the spin frustrating effect of the plaquette-diagonal Fe-Fe hopping
is remarked. A spin 'striped' state is stable in a broad range of couplings in
the undoped regime, in agreement with neutron scattering. Adding two electrons
to the undoped ground state of a small cluster, the dominant pairing operators
are found. Depending on parameters, two pairing operators were identified: they
involve inter-xz-yz orbital combinations forming spin singlets or triplets,
transforming according to the B_2g and A_2g representations of the D_4h group,
respectively.


title: On Recovery of Sparse Signals via $\ell_1$ Minimization

abstract:
  This article considers constrained $\ell_1$ minimization methods for the
recovery of high dimensional sparse signals in three settings: noiseless,
bounded error and Gaussian noise. A unified and elementary treatment is given
in these noise settings for two $\ell_1$ minimization methods: the Dantzig
selector and $\ell_1$ minimization with an $\ell_2$ constraint. The results of
this paper improve the existing results in the literature by weakening the
conditions and tightening the error bounds. The improvement on the conditions
shows that signals with larger support can be recovered accurately. This paper
also establishes connections between restricted isometry property and the
mutual incoherence property. Some results of Candes, Romberg and Tao (2006) and
Donoho, Elad, and Temlyakov (2006) are extended.


title: Real-time gauge/gravity duality

abstract:
  We present a general prescription for the holographic computation of
real-time n-point functions in non-trivial states. In QFT such real-time
computations involve a choice of a time contour in the complex time plane. The
holographic prescription amounts to ``filling in'' this contour with bulk
solutions: real segments of the contour are filled in with Lorentzian solutions
while imaginary segments are filled in with Riemannian solutions and
appropriate matching conditions are imposed at the corners of the contour. We
illustrate the general discussion by computing the 2-point function of a scalar
operator using this prescription and by showing that this leads to an
unambiguous answer with the correct i epsilon insertions.


title:
On the calculation of the cohomology of the third finite subset space of
  spheres

abstract:
  In this paper we provide a computation of the mod 2 cohomology groups of the
third finite subset space of the sphere $S^n$ using known results about the
cohomology of the symmetric product of spheres.


title:
Sum rules and dualities for generalized parton distributions: is there a
  holographic principle?

abstract:
  To leading order approximation, the physical content of generalized parton
distributions (GPDs) that is accessible in deep virtual electroproduction of
photons or mesons is contained in their value on the cross-over trajectory.
This trajectory separates the t-channel and s-channel dominated GPD regions.
The underlying Lorentz covariance implies correspondence between these two
regions through their relation to GPDs on the cross-over trajectory. This point
of view leads to a family of GPD sum rules which are a quark analogue of finite
energy sum rules and it guides us to a new phenomenological GPD concept. As an
example, we discuss the constraints from the JLab/Hall A data on the dominant
u-quark GPD H. The question arises whether GPDs are governed by some kind of
holographic principle.


title: e+e- Pairs: a clock and a thermometer of heavy ion collisions

abstract:
  Recently, there is growing evidence that a new state of matter is formed in
sqrt(s_NN)= 200 GeV Au+Au collisions at RHIC: a strongly coupled Quark Gluon
Plasma of partonic degrees of freedom which develops a collective motion.
Dilepton spectra are not affected by strong interaction and can therefore probe
the whole time evolution of the collision. Thus they may be sensitive to onset
of deconfinement, chiral symmetry restoration, as well as the production of
thermal photons. The PHENIX experiment measured the production of e+e- pairs in
p+p and Au+Au collisions at sqrt(s_NN)= 200 GeV. An enhanced dilepton yield in
the mass range 150<m_ee<750 MeV/c^2 is measured. The excess increases faster
with centrality than the number of participating nucleons and is concentrated
at p_T<1GeV/c. At higher p_T the excess below 300 MeV/c^2 has been related to
an enhanced production of direct photons possibly of thermal origin.


title: The Tsallis entropy and the Shannon entropy of a universal probability

abstract:
  We study the properties of Tsallis entropy and Shannon entropy from the point
of view of algorithmic randomness. In algorithmic information theory, there are
two equivalent ways to define the program-size complexity K(s) of a given
finite binary string s. In the standard way, K(s) is defined as the length of
the shortest input string for the universal self-delimiting Turing machine to
output s. In the other way, the so-called universal probability m is introduced
first, and then K(s) is defined as -log_2 m(s) without reference to the concept
of program-size. In this paper, we investigate the properties of the Shannon
entropy, the power sum, and the Tsallis entropy of a universal probability by
means of the notion of program-size complexity. We determine the convergence or
divergence of each of these three quantities, and evaluate its degree of
randomness if it converges.


title:
The Turbulent Warm Ionized Medium: Emission Measure Distribution and MHD
  Simulations

abstract:
  We present an analysis of the distribution of H-alpha emission measures for
the warm ionized medium (WIM) of the Galaxy using data from the Wisconsin
H-Alpha Mapper (WHAM) Northern Sky Survey. Our sample is restricted to Galactic
latitudes |b| > 10. We removed sightlines intersecting nineteen high-latititude
classical H II regions, leaving only sightlines that sample the diffuse WIM.
The distribution of EM sin |b| for the full sample is poorly characterized by a
single normal distribution, but is extraordinarily well fit by a lognormal
distribution, with <log EM sin |b|> = 0.146 +/- 0.001 and standard deviation
0.190 +/- 0.001. <log EM sin |b|> drops from 0.260 +/- 0.002 at Galactic
latitude 10<|b|<30 to 0.038 +/- 0.002 at Galactic latitude 60<|b|<90. The
distribution may widen slightly at low Galactic latitude. We compare the
observed EM distribution function to the predictions of three-dimensional
magnetohydrodynamic simulations of isothermal turbulence within a
non-stratified interstellar medium. We find that the distribution of EM sin |b|
is well described by models of mildy supersonic turbulence with a sonic Mach
number of ~1.4-2.4. The distribution is weakly sensitive to the magnetic field
strength. The model also successfully predicts the distribution of dispersion
measures of pulsars and H-alpha line profiles. In the best fitting model, the
turbulent WIM occupies a vertical path length of 400-500 pc within the 1.0-1.8
kpc scale height of the layer. The WIM gas has a lognormal distribution of
densities with a most probable electron density n_{pk} = 0.03 cm^{-3}. We also
discuss the implications of these results for interpreting the filling factor,
the power requirement, and the magnetic field of the WIM.


title: Quasar candidates selection in the Virtual Observatory era

abstract:
  We present a method for the photometric selection of candidate quasars in
multiband surveys. The method makes use of a priori knowledge derived from a
subsample of spectroscopic confirmed QSOs to map the parameter space. The
disentanglement of QSOs candidates and stars is performed in the colour space
through the combined use of two algorithms, the Probabilistic Principal
Surfaces and the Negative Entropy clustering, which are for the first time used
in an astronomical context. Both methods have been implemented in the VONeural
package on the Astrogrid VO platform. Even though they belong to the class of
the unsupervised clustering tools, the performances of the method are optimized
by using the available sample of confirmed quasars and it is therefore possible
to learn from any improvement in the available "base of knowledge". The method
has been applied and tested on both optical and optical plus near infrared data
extracted from the visible SDSS and infrared UKIDSS-LAS public databases. In
all cases, the experiments lead to high values of both efficiency and
completeness, comparable if not better than the methods already known in the
literature. A catalogue of optical candidate QSOs extracted from the SDSS DR7
Legacy photometric dataset has been produced and is publicly available at the
URL voneural.na.infn.it/qso.html.


title: Integral Transforms and Drinfeld Centers in Derived Algebraic Geometry

abstract:
  We study the interaction between geometric operations on stacks and algebraic
operations on their categories of sheaves. We work in the general setting of
derived algebraic geometry: our basic objects are derived stacks X and their
oo-categories QC(X) of quasicoherent sheaves. We show that for a broad class of
derived stacks, called perfect stacks, algebraic and geometric operations on
their categories of sheaves are compatible. We identify the category of sheaves
on a fiber product with the tensor product of the categories of sheaves on the
factors. We also identify the category of sheaves on a fiber product with
functors between the categories of sheaves on the factors (thus realizing
functors as integral transforms, generalizing a theorem of Toen for ordinary
schemes). As a first application, for a perfect stack X, consider QC(X) with
its usual monoidal tensor product. Then our main results imply the equivalence
of the Drinfeld center (or Hochschild cohomology category) of QC(X), the trace
(or Hochschild homology category) of QC(X) and the category of sheaves on the
loop space of X. More generally, we show that the E_n-center and the E_n-trace
(or E_n-Hochschild cohomology and homology categories respectively) of QC(X)
are equivalent to the category of sheaves on the space of maps from the
n-sphere into X. This directly verifies geometric instances of the categorified
Deligne and Kontsevich conjectures on the structure of Hochschild cohomology.
As a second application, we use our main results to calculate the Drinfeld
center of categories of linear endofunctors of categories of sheaves. This
provides concrete applications to the structure of Hecke algebras in geometric
representation theory. Finally, we explain how all of the above results can be
interpreted in the context of topological field theory.


title: Operator-valued dyadic BMO spaces

abstract:
  We consider BMO spaces of operator-valued functions, among them the space of
operator-valued functions $B$ which define a bounded paraproduct on $L^2(H)$.
We obtain several equivalent formulations of $\|\pi_B\|$ in terms of the norm
of the "sweep" function of $B$ or of averages of the norms of martingales
transforms of $B$ in related spaces. Furthermore, we investigate a connection
between John-Nirenberg type inequalities and Carleson-type inequalities via a
product formula for paraproducts and deduce sharp dimensional estimates for
John-Nirenberg type inequalities.


title:
Modeling gravitational recoil from precessing highly-spinning
  unequal-mass black-hole binaries

abstract:
  We measure the gravitational recoil for unequal-mass-black- hole-binary
mergers, with the larger BH having spin a/m^H=0.8, and the smaller BH
non-spinning. We choose our configurations such that, initially, the spins lie
on the orbital plane. The spin and orbital plane precess significantly, and we
find that the out-of plane recoil (i.e. the recoil perpendicular to the orbital
plane around merger) varies as \eta^2 / (1+q), in agreement with our previous
prediction, based on the post-Newtonian scaling.


title:
Understanding jet quenching and medium response with di-hadron
  correlation

abstract:
  A brief review of the $p_T$ dependence of the dihadron correlations from RHIC
is presented. We attempt to construct a consistent picture that can describe
the data as a whole, focusing on the following important aspects, 1) the
relation between jet fragmentation of survived jet and medium response to
quenched jets, 2) the possible origin of the medium response and its relation
to intermediate $p_T$ physics for single hadron production, 3) the connection
between the near-side ridge and away-side cone, 4) and their relations to low
energy results.


title:
Prospects for an electron electric dipole moment search in metastable
  ThO and ThF$^{\rm +}$

abstract:
  The observation of an electron electric dipole moment (eEDM) would have major
ramifications for the standard model of physics. Polar molecules offer a
near-ideal laboratory for such searches due to the large effective electric
field (${\bf F}_{\rm eff}$), on order of tens of GV/cm that can be easily
oriented in the lab frame. We present an improved method for simply and
accurately determining ${\bf F}_{\rm eff}$, in a heavy polar molecule, allowing
for a quick determination of candidates for an eEDM experiment. We apply this
method to ThO and ThF$^{\rm +}$, both of which possess metastable $^3\Delta$
electronic states. The values of ${\bf F}_{\rm eff}$ in ThO and ThF$^{\rm +}$
are estimated to be 104 GV/cm and 90 GV/cm respectively, and are therefore two
of the best known candidates for the eEDM search.


title: Morphing of Triangular Meshes in Shape Space

abstract:
  We present a novel approach to morph between two isometric poses of the same
non-rigid object given as triangular meshes. We model the morphs as linear
interpolations in a suitable shape space $\mathcal{S}$. For triangulated 3D
polygons, we prove that interpolating linearly in this shape space corresponds
to the most isometric morph in $\mathbb{R}^3$. We then extend this shape space
to arbitrary triangulations in 3D using a heuristic approach and show the
practical use of the approach using experiments. Furthermore, we discuss a
modified shape space that is useful for isometric skeleton morphing. All of the
newly presented approaches solve the morphing problem without the need to solve
a minimization problem.


title: Inflationary Cosmology as a Probe of Primordial Quantum Mechanics

abstract:
  We show that inflationary cosmology may be used to test the statistical
predictions of quantum theory at very short distances and at very early times.
Hidden-variables theories, such as the pilot-wave theory of de Broglie and
Bohm, allow the existence of vacuum states with non-standard field fluctuations
('quantum nonequilibrium'). We show that inflationary expansion can transfer
microscopic nonequilibrium to macroscopic scales, resulting in anomalous power
spectra for the cosmic microwave background. The conclusions depend only weakly
on the details of the de Broglie-Bohm dynamics. We discuss, in particular, the
nonequilibrium breaking of scale invariance for the primordial (scalar) power
spectrum. We also show how nonequilibrium can generate primordial perturbations
with non-random phases and inter-mode correlations (primordial
non-Gaussianity). We address the possibility of a low-power anomaly at large
angular scales, and show how it might arise from a nonequilibrium suppression
of quantum noise. Recent observations are used to set an approximate bound on
violations of quantum theory in the early universe.


title: Superconducting qubits

abstract:
  From a physicist's standpoint, the most interesting part of quantum computing
research may well be the possibility to probe the boundary between the quantum
and the classical worlds. The more macroscopic are the structures involved, the
better. So far, the most "macroscopic" qubit prototypes that have been studied
in the laboratory are certain kinds of superconducting qubits. To get a feeling
for how macroscopic these systems can be, the states of flux qubits which are
brought in a quantum superposition corresponds to currents composed of as much
as 10^5-10^6 electrons flowing in opposite directions in a superconducting
loop. Non-superconducting qubits realized so far are all essentially
microscopic.


title: New XMM-Newton observations of SNRs in the SMC

abstract:
  A complete overview of the supernova remnant (SNR) population is required to
investigate their evolution and interaction with the surrounding interstellar
medium in the Small Magellanic Cloud (SMC). Recent XMM-Newton observations of
the SMC cover three known SNRs (DEM S5, SNR B0050-72.8, and SNR B0058-71.8),
which are poorly studied and are X-ray faint. We used new multi-frequency
radio-continuum surveys and new optical observations at Ha, [SII], and [OIII]
wavelengths, in combination with the X-ray data, to investigate their
properties and to search for new SNRs in the SMC. We used X-ray source
selection criteria and found one SMC object with typical SNR characteristics
(HFPK 334), that was initially detected by ROSAT. We analysed the X-ray spectra
and present multi-wavelength morphological studies of the three SNRs and the
new candidate. Using a non-equilibrium ionisation collisional plasma model, we
find temperatures kT around 0.18 keV for the three known remnants and 0.69 keV
for the candidate. The low temperature, low surface brightness, and large
extent of the three remnants indicates relatively large ages. The emission from
the new candidate (HFPK 334) is more centrally peaked and the higher
temperature suggests a younger remnant. Our new radio images indicate that a
pulsar wind nebulae (PWN) is possibly associated with this object. The SNRs
known in the SMC show a variety of morphological structures that are relatively
uncorrelated in the different wavelength bands, probably caused by the
different conditions in the surrounding medium with which the remnant
interacts.


title: Bethe Ansatz Solutions to Quasi Exactly Solvable Difference Equations

abstract:
  Bethe ansatz formulation is presented for several explicit examples of quasi
exactly solvable difference equations of one degree of freedom which are
introduced recently by one of the present authors. These equations are
deformation of the well-known exactly solvable difference equations of the
Meixner-Pollaczek, continuous Hahn, continuous dual Hahn, Wilson and
Askey-Wilson polynomials. Up to an overall factor of the so-called pseudo
ground state wavefunction, the eigenfunctions within the exactly solvable
subspace are given by polynomials whose roots are solutions of the associated
Bethe ansatz equations. The corresponding eigenvalues are expressed in terms of
these roots.


title:
Toward First-Principle Simulations of Galaxy Formation: II.
  Shock-Induced Starburst at a Collision Interface During the First Encounter
  of Interacting Galaxies

abstract:
  We investigated the evolution of interacting disk galaxies using
high-resolution $N$-body/SPH simulations, taking into account the multiphase
nature of the interstellar medium (ISM). In our high-resolution simulations, a
large-scale starburst occurred naturally at the collision interface between two
gas disks at the first encounter, resulting in the formation of star clusters.
This is consistent with observations of interacting galaxies. The probability
distribution function (PDF) of gas density showed clear change during the
galaxy-galaxy encounter. The compression of gas at the collision interface
between the gas disks first appears as an excess at $n_{\rm H} \sim 10{\rm
cm^{-3}}$ in the PDF, and then the excess moves to higher densities ($n_{\rm H}
\gtrsim 100{\rm cm^{-3}}$) in a few times $10^7$ years where starburst takes
place. After the starburst, the PDF goes back to the quasi-steady state. These
results give a simple picture of starburst phenomena in galaxy-galaxy
encounters.


title: GH $\alpha$ FaS : Galaxy H-alpha Fabry-Perot System for the WHT

abstract:
  GH$\alpha$FaS a new Fabry-Perot system, is now available at the William
Herschel Telescope. It was mounted, for the first time, at the Nasmyth focus of
the 4.2 meter WHT on La Palma in July 2007. Using modern technology, with a
spectral resolution of the order R$\sim$15000, and with a seeing limited
spatial resolution, GH$\alpha$FaS will provide a new look at the H$\alpha$
-emitting gas over a 4.8 arcminutes circular field in the nearby universe. Many
science programs can be done on a 4.2 metre class telescope in world class
seeing conditions with a scanning Fabry-Perot. Not only galaxies but HII
regions, planetary nebulae, supernova remnants and the diffuse interstellar
medium are subjects for which unique data can be aquired rapidly. Astronomers
from the Laboratoire d'Astrophysique Exp\'erimentale (LAE) in Montr\'eal, the
Laboratoire d'Astrophysique de Marseille (LAM-OAMP), and the Instituto de
Astrof\'isica de Canarias (IAC), have inaugurated GH$\alpha$FaS by studying in
detail the dynamics of some nearby spiral galaxies. A robust set of
state-of-the-arts tools for reducing and analyzing the data cubes obtained with
GH$\alpha$FaS has also been developed.


title:
Primordial magnetic fields from second-order cosmological perturbations:
  Tight coupling approximation

abstract:
  We explore the possibility of generating large-scale magnetic fields from
second-order cosmological perturbations during the pre-recombination era. The
key process for this is Thomson scattering between the photons and the charged
particles within the cosmic plasma. To tame the multi-component interacting
fluid system, we employ the tight coupling approximation. It is shown that the
source term for the magnetic field is given by the vorticity, which signals the
intrinsically second-order quantities, and the product of the first order
perturbations. The vorticity itself is sourced by the product of the
first-order quantities in the vorticity evolution equation. The magnetic fields
generated by this process are estimated to be $\sim 10^{-29} $Gauss on the
horizon scale at the recombination epoch. Although our rough estimate suggests
that the current generation mechanism can work even on smaller scales, more
careful investigation is needed to make clear whether it indeed works in a wide
range of spatial scales.


title: The fermion mass at next-to-leading order in the HTL effective theory

abstract:
  The calculation of the real part of a quasi-particle dispersion relation at
next-to-leading order in the hard thermal loop effective theory is a very
difficult problem. Even though the hard thermal loop effective theory is almost
20 years old, there is only one next-to-leading order calculation of the real
part of a quasi-particle dispersion relation in the literature. In this paper,
we calculate the fermion mass in QED and QCD at next-to-leading order. For QED
the result is M=eT/sqrt{8} * [1-(1.427 \pm 0.02)e/4pi] and for QCD with N_f=2
and N_c=3 we obtain M=gT/sqrt{6} * [1+(1.867 \pm 0.02)g/4pi].


title:
Toward Identification of Order Parameters in Skutterudites - a
  Wonderland of Strong Correlation Physics -

abstract:
  Current status is described toward identifying unconventional order
parameters in filled skutterudites with unique ordering phenomena. The order
parameters in PrFe$_4$P$_{12}$ and PrRu$_4$P$_{12}$ are discussed in relation
to associated crystalline electric field (CEF) states and angular form factors.
By phenomenological Landau analysis, it is shown that a scalar order model
explains most properties in both PrFe$_4$P$_{12}$ and PrRu$_4$P$_{12}$ with
very different magnetic properties. In particular, the highly anisotropic
susceptibility induced by uniaxial pressure in PrFe$_4$P$_{12}$ is explained in
terms of two types of couplings. In the case of SmRu$_4$P$_{12}$, the main
order parameter at low field is identified as magnetic octupoles. A microscopic
mechanism is proposed how the dipole and octupole degrees of freedom mix under
the point group $T_h$ of skutterudites.


title: Scaling Relations for Collision-less Dark Matter Turbulence

abstract:
  Many scaling relations are observed for self-gravitating systems in the
universe. We explore the consistent understanding of them from a simple
principle based on the proposal that the collision-less dark matter fluid terns
into a turbulent state, i.e. dark turbulence, after crossing the caustic
surface in the non-linear stage. The dark turbulence will not eddy dominant
reflecting the collision-less property. After deriving Kolmogorov scaling laws
from Navier-Stokes equation by the method similar to the one for Smoluchowski
coagulation equation, we apply this to several observations such as the
scale-dependent velocity dispersion, mass-luminosity ratio, magnetic fields,
and mass-angular momentum relation, power spectrum of density fluctuations.
They all point the concordant value for the constant energy flow per mass: $0.3
cm^2/sec^3$, which may be understood as the speed of the hierarchical
coalescence process in the cosmic structure formation.


title: A Computer Search for N1L-Configurations

abstract:
  In an earlier paper the author defined N1L configurations, and stated a
conjecture concerning them which would lead to an improvement by a constant
factor to the sphere-packing bound for linear double error correcting codes.
Here a computer search is presented, in an effort to gather evidence on the
conjecture.


title:
Koszul duality in deformation quantization and Tamarkin's approach to
  Kontsevich formality

abstract:
  Let $\alpha$ be a quadratic Poisson bivector on a vector space $V$. Then one
can also consider $\alpha$ as a quadratic Poisson bivector on the vector space
$V^*[1]$. Fixed a universal deformation quantization (prediction some weights
to all Kontsevich graphs [K97]), we have deformation quantization of the both
algebras $S(V^*)$ and $\Lambda(V)$. These are graded quadratic algebras, and
therefore Koszul algebras. We prove that for some universal deformation
quantization, independent on $\alpha$, these two algebras are Koszul dual. We
characterize some deformation quantizations for which this theorem is true in
the framework of the Tamarkin's theory [T1].


title:
Magnetic properties of the charge density wave compounds RTe3, R=Y, La,
  Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er & Tm

abstract:
  The antiferromagnetic transition is investigated in the rare-earth (R)
tritelluride RTe3 family of charge density wave (CDW) compounds via specific
heat, magnetization and resistivity measurements. Observation of the opening of
a superzone gap in the resistivity of DyTe3 indicates that additional nesting
of the reconstructed Fermi surface in the CDW state plays an important role in
determining the magnetic structure.


title: Super-elastic collisions of thermal activated nanoclusters

abstract:
  Impact processes of nanoclusters subject to thermal fluctuations are
investigated, theoretically. In the former half of the paper, we discuss the
basis of quasi-static theory. In the latter part, we carry out the molecular
dynamics simulation of collisions between two identical nanoclusters, and
report some statistical properties of impacts of nanoclusters.


title: Spectral parameterization for the power sums of quantum supermatrix

abstract:
  A parameterization for the power sums of GL(m|n) type quantum (super)matrix
is obtained in terms of it's spectral values.


title:
Quasistatic rheology, force transmission and fabric properties of a
  packing of irregular polyhedral particles

abstract:
  By means of contact dynamics simulations, we investigate a dense packing
composed of polyhedral particles under quasistatic shearing. The effect of
particle shape is analyzed by comparing the polyhedra packing with a packing of
similar characteristics except for the spherical shape of the particles. The
polyhedra packing shows higher shear stress and dilatancy but similar
stress-dilatancy relation compared to the sphere packing. A harmonic
approximation of granular fabric is presented in terms of branch vectors
(connecting particle centers) and contact force components along and
perpendicular to the branch vectors. It is found that the origin of enhanced
shear strength of the polyhedra packing lies in its higher force anisotropy
with respect to the sphere packing which has a higher fabric anisotropy.
Various contact types (face-vertex, face-face, etc) contribute differently to
force transmission and fabric anisotropy. In particular, most face-face
contacts belong to strong force chains along the major principal stress
direction whereas vertex-face contacts are correlated with weak forces and
oriented on average along the minor principal stress direction in steady
shearing.


title:
Test of the Littlest Higgs model through the correlation among W boson,
  top quark and Higgs masses

abstract:
  Motivated by the recent precision measurements of the W boson mass and top
quark mass, we test the Littlest Higgs model by confronting the prediction of
M_W with the current and prospective measurements of M_W and M_t as well as
through the correlation among M_W, M_t and Higgs mass. We argue that the
current values and accuracy of M_W and M_t measurements tend to favor the
Littlest Higgs model over the standard model, although the most recent
electroweak data may appear to be consistent with the standard model
prediction. In this analysis, the upper bound on the global SU(5) symmetry
breaking scale turned out to be 26.3 TeV. We also discuss how the masses of the
heavy gauge boson M_B in the Littlest Higgs model can be predicted from the
constraints on the model parameters.


title: Normal forms for real quadratic forms

abstract:
  We investigate the non-diagonal normal forms of a quadratic form on R^n, in
particular for n=3. For this case it is shown that the set of normal forms is
the closure of a 5-dimensional submanifold in the 6-dimensional Grassmannian of
2-dimensional subspaces of \R^5.


title: Nondiscriminatory Propagation on Trees

abstract:
  We consider a discrete-time dynamical process on graphs, firstly introduced
in connection with a protocol for controlling large networks of spin 1/2
quantum mechanical particles [Phys. Rev. Lett. 99, 100501 (2007)]. A
description is as follows: each vertex of an initially selected set has a
packet of information (the same for every element of the set), which will be
distributed among vertices of the graph; a vertex v can pass its packet to an
adjacent vertex w only if w is its only neighbour without the information. By
mean of examples, we describe some general properties, mainly concerning
homeomorphism, and redundant edges. We prove that the cardinality of the
smallest sets propagating the information in all vertices of a balanced m-ary
tree of depth k is exactly (m^{k+1}+(-1)^{k})/(m+1). For binary trees, this
number is related to alternating sign matrices.


title: Orbital Ordering and Magnetic Interactions in BiMnO$_3$

abstract:
  This work is devoted to the analysis of orbital patterns and related to them
interatomic magnetic interactions in centrosymmetric monoclinic structures of
BiMnO$_3$, which have been recently determined experimentally. First, we set up
an effective lattice fermion model for the manganese 3d bands and derive
parameters of this model entirely from first-principles electronic structure
calculations. Then, we solve this model in terms of the mean-field Hartree-Fock
method and derive parameters of interatomic magnetic interactions between Mn
ions. We argue that although nearest-neighbor interactions favors the
ferromagnetism, they compete with longer-range antiferromagnetic (AFM)
interactions, the existence of which is directly related with the peculiar
geometry of the orbital ordering pattern realized in BiMnO$_3$ below 474 K.
These AFM interactions favor an AFM phase, which breaks the inversion symmetry.
The formation of the AFM phase is assisted by the orbital degrees of freedom,
which tend to adjust the nearest-neighbor magnetic interactions in the
direction, which further stabilizes this phase. We propose that the
multiferroelectric behavior, observed in BiMnO$_3$, may be related with the
emergence of the AFM phase under certain conditions.


title:
Domain-wall structure of a classical Heisenberg ferromagnet on a Mobius
  strip

abstract:
  We study theoretically the structure of domain walls in ferromagnetic states
on Mobius strips. A two-dimensional classical Heisenberg ferromagnet with
single-site anisotropy is treated within a mean-field approximation by taking
into account the boundary condition to realize the Mobius geometry. It is found
that two types of domain walls can be formed, namely, parallel or perpendicular
to the circumference, and that the relative stability of these domain walls is
sensitive to the change in temperature and an applied magnetic field. The
magnetization has a discontinuity as a function of temperature and the external
field.


title:
Information, Energy and Density for Ad Hoc Sensor Networks over
  Correlated Random Fields: Large Deviations Analysis

abstract:
  Using large deviations results that characterize the amount of information
per node on a two-dimensional (2-D) lattice, asymptotic behavior of a sensor
network deployed over a correlated random field for statistical inference is
investigated. Under a 2-D hidden Gauss-Markov random field model with symmetric
first order conditional autoregression, the behavior of the total information
[nats] and energy efficiency [nats/J] defined as the ratio of total gathered
information to the required energy is obtained as the coverage area, node
density and energy vary.


title: In situ formation of the massive stars around SgrA*

abstract:
  The formation of the massive young stars surrounding SgrA* is still an open
question. In this paper, we simulate the infall of an isothermal, turbulent
molecular cloud towards the Galactic Centre (GC). As it spirals towards the GC,
the molecular cloud forms a small and dense disc around SgrA*. Efficient star
formation (SF) is expected to take place in such a dense disc. We model SF by
means of sink particles. At ~6x10^5 yr, ~6000 solar masses of stars have
formed, and are confined within a thin disc with inner and outer radius of 0.06
and 0.5 pc, respectively. Thus, this preliminary study shows that the infall of
a molecular cloud is a viable scenario for the formation of massive stars
around SgrA*. Further studies with more realistic radiation physics and SF will
be required to better constrain this intriguing scenario.


title:
Measurement of single charged pion production in the charged-current
  interactions of neutrinos in a 1.3 GeV wide band beam

abstract:
  Single charged pion production in charged-current muon neutrino interactions
with carbon is studied using data collected in the K2K long-baseline neutrino
experiment. The mean energy of the incident muon neutrinos is 1.3 GeV. The data
used in this analysis are mainly from a fully active scintillator detector,
SciBar. The cross section for single $\pi^{+}$ production in the resonance
region ($W<2$ GeV/$c^2$) relative to the charged-current quasi-elastic cross
section is found to be 0.734 $^{+0.140}_{-0.153}$. The energy-dependent cross
section ratio is also measured. The results are consistent with a previous
experiment and the prediction of our model.


title:
Thermodynamics and phase transitions in the Born-Infeld-anti-de Sitter
  black holes

abstract:
  We investigate the Born-Infeld-anti-de Sitter black hole (BIAdS) solutions in
the four dimensions, which is a nonlinear generalization of the
Reissner-Norstr\"om-AdS black hole (RNAdS). We analyze all thermodynamic
quantities of the BIAdS in the canonical ensembles, which are characterized by
the charge $Q$, the mass $M$, the nonlinear parameter $b$, comparing with those
of the RNAdS and Schwarzschild-AdS black hole. We find the forbidden region of
$0\le bQ <0.5$ for the presence of a charged BIAdS. We also discuss the
Hawking-Page phase transitions in the BIAdS black holes. Here we obtain a new
Hawking-Page phase transition for the $bQ=0.5$ critical BIAdS.


title: Shot noise of a mesoscopic two-particle collider

abstract:
  We investigate the shot noise generated by particle emission from a
mesoscopic capacitor into an edge state reflected and transmitted at a quantum
point contact (QPC). For a capacitor subject to a periodic voltage the
resulting shot noise is proportional to the number of particles (both electrons
and holes) emitted during a period. It is proportional to the product of
transmission and reflection probability of the QPC independent of the applied
voltage but proportional to the driving frequency. If two driven capacitors are
coupled to a QPC at different sides then the resulting shot noise is maximally
the sum of noises produced by each of the capacitors. However the noise is
suppressed depending on the coincidence of the emission of two particles of the
same kind.


title: Rabi switch of condensate wavefunctions in a multicomponent Bose gas

abstract:
  Using a time-dependent linear (Rabi) coupling between the components of a
weakly interacting multicomponent Bose-Einstein condensate (BEC), we propose a
protocol for transferring the wavefunction of one component to the other. This
"Rabi switch" can be generated in a binary BEC mixture by an electromagnetic
field between the two components, typically two hyperfine states. When the
wavefunction to be transfered is - at a given time - a stationary state of the
multicomponent Hamiltonian, then, after a time delay (depending on the Rabi
frequency), it is possible to have the same wavefunction on the other
condensate. The Rabi switch can be used to transfer also moving bright
matter-wave solitons, as well as vortices and vortex lattices in
two-dimensional condensates. The efficiency of the proposed switch is shown to
be 100% when inter-species and intra-species interaction strengths are equal.
The deviations from equal interaction strengths are analyzed within a two-mode
model and the dependence of the efficiency on the interaction strengths and on
the presence of external potentials is examined in both 1D and 2D settings.


title: Infrared to X-ray observations of PKS 2155-304 in a low state

abstract:
  AIMS: Our goal is to understand the nature of blazars and the mechanisms for
the generation of high-energy gamma-rays, through the investigation of the
prototypical blazar PKS 2155-304, which shows complex behaviour. METHODS: We
analyze simultaneous infrared-to-X-ray observations obtained with XMM-Newton
and REM on November 7, 2006, when the source was in a low X-ray state. We
perform a comparative analysis of these results with those obtained from
previous observations in different brightness states. RESULTS: We found that
the peak of the synchrotron emission moved from ultraviolet to optical
wavelengths and the X-ray spectrum is best fit with a broken power law model
with Gamma_2 ~ 2.4 harder than Gamma_1 ~ 2.6 and a break at about 3.5 keV. This
suggests that the soft X-rays (E < 3.5 keV) are related to the high-energy tail
of the synchrotron emission, while the hard X-rays (E > 3.5 keV) are from the
energy region between the synchrotron and inverse-Compton humps. The different
variability at energies below and above the break strengthens this hypothesis.
Our results also stress the importance of monitoring this source at both low
and high energies to better characterize its variability behaviour.


title:
Refined BPS state counting from Nekrasov's formula and Macdonald
  functions

abstract:
  It has been argued that the Nekrasov's partition function gives the
generating function of refined BPS state counting in the compactification of M
theory on local Calabi-Yau spaces. We show that a refined version of the
topological vertex we proposed before (hep-th/0502061) is a building block of
the Nekrasov's partition function with two equivariant parameters. Compared
with another refined topological vertex by Iqbal-Kozcaz-Vafa (hep-th/0701156),
our refined vertex is expressed entirely in terms of the specialization of the
Macdonald symmetric functions which is related to the equivariant character of
the Hilbert scheme of points on C^2. We provide diagrammatic rules for
computing the partition function from the web diagrams appearing in geometric
engineering of Yang-Mills theory with eight supercharges. Our refined vertex
has a simple transformation law under the flop operation of the diagram, which
suggests that homological invariants of the Hopf link are related to the
Macdonald functions.


title:
Specification of an extensible and portable file format for electronic
  structure and crystallographic data

abstract:
  In order to allow different software applications, in constant evolution, to
interact and exchange data, flexible file formats are needed. A file format
specification for different types of content has been elaborated to allow
communication of data for the software developed within the European Network of
Excellence "NANOQUANTA", focusing on first-principles calculations of materials
and nanosystems. It might be used by other software as well, and is described
here in detail. The format relies on the NetCDF binary input/output library,
already used in many different scientific communities, that provides
flexibility as well as portability accross languages and platforms. Thanks to
NetCDF, the content can be accessed by keywords, ensuring the file format is
extensible and backward compatible.


title: On normal contact pairs

abstract:
  We consider manifolds endowed with a contact pair structure. To such a
structure are naturally associated two almost complex structures. If they are
both integrable, we call the structure a normal contact pair. We generalize the
Morimoto's Theorem on product of almost contact manifolds to flat bundles. We
construct some examples on Boothby--Wang fibrations over contact-symplectic
manifolds. In particular, these results give new methods to construct complex
manifolds.