title: Possibility of measuring a0(980)-f0(980) mixing from J/psi -> phi a0

abstract:
  The a0(980)-f0(980) mixing intensity has been predicted to be in the range of
0.01 to 0.1 by various theoretical models, but lacking firm experimental
observation. We examine the possibility of extracting the a0(980)-f0(980)
mixing from J/psi -> phi f0 -> phi a0 reaction at upgraded Beijing Electron
Positron Collider with BESIII detector. While the branching ratio of this
process through the a0(980)-f0(980) mixing is expected to be about $O(10^{-6})$
similar to the estimated total amount from two background reactions J/psi ->
gamma* -> phi a0 and J/psi -> K* K + c.c. -> phi a0, the peak width from the
a0(980)-f0(980) mixing is about 8 MeV, much smaller than that from other
mechanisms. With $10^9$ $J/\psi$ events at BESIII, the a0(980)-f0(980) mixing
intensity is expected to be unambiguously and precisely measured.


title:
The Long Term Fate of Our Digital Belongings: Toward a Service Model for
  Personal Archives

abstract:
  We conducted a preliminary field study to understand the current state of
personal digital archiving in practice. Our aim is to design a service for the
long-term storage, preservation, and access of digital belongings by examining
how personal archiving needs intersect with existing and emerging archiving
technologies, best practices, and policies. Our findings not only confirmed
that experienced home computer users are creating, receiving, and finding an
increasing number of digital belongings, but also that they have already lost
irreplaceable digital artifacts such as photos, creative efforts, and records.
Although participants reported strategies such as backup and file replication
for digital safekeeping, they were seldom able to implement them consistently.
Four central archiving themes emerged from the data: (1) people find it
difficult to evaluate the worth of accumulated materials; (2) personal storage
is highly distributed both on- and offline; (3) people are experiencing
magnified curatorial problems associated with managing files in the aggregate,
creating appropriate metadata, and migrating materials to maintainable formats;
and (4) facilities for long-term access are not supported by the current
desktop metaphor. Four environmental factors further complicate archiving in
consumer settings: the pervasive influence of malware; consumer reliance on ad
hoc IT providers; an accretion of minor system and registry inconsistencies;
and strong consumer beliefs about the incorruptibility of digital forms, the
reliability of digital technologies, and the social vulnerability of networked
storage.


title:
A Search for CO(J=3-2) Emission from the Host Galaxy of GRB 980425 with
  the Atacama Submillimeter Telescope Experiment

abstract:
  We report on a deep search for CO(J=3-2) line emission from the host galaxy
of GRB 980425 with the Atacama Submillimeter Telescope Experiment (ASTE). We
observed five points of the galaxy covering the entire region. After combining
all of the spectra, we obtained a global spectrum with the rms noise level of
3.3 mK in T_mb scale at a velocity resolution of 10 km s^-1. No significant
emission was detected, though we find a marginal emission feature in the
velocity range corresponding to the redshift of the galaxy. We derive 3 sigma
upper limits on the global properties: the velocity-integrated CO(3-2)
intensity of I_CO(3-2) < 0.26 K km s^-1 by adopting a velocity width of 67 km
s^-1; the H_2 column density of N(H_2) < 3 x 10^20 cm^-2; the molecular gas
mass of M(H_2) < 3 x 10^8 M_sun, by assuming a CO line luminosity to H_2
molecular gas mass conversion factor of X_CO = 5.0 x 10^20 cm^-2 (K km
s^-1)^-1; and the star formation rate of SFR < 0.1 M_sun yr^-1, based on the
Schmidt law. The SFR is consistent with the previous results of H_alpha and
mid-IR observations, thereby suggesting that there is no significant obscured
star formation in the host galaxy of GRB 980425. This result implies that there
is a variety of GRB hosts with regard to the presence of obscured star
formation.


title:
Equivalence of different descriptions for $\eta$ Particle in Simplest
  Little Higgs Model

abstract:
  In SU(3) simplest little Higgs model, a characteristic particle is the light
pseudoscalar boson eta, it leads interesting signals in the LHC/ILC and is
studied in literature with different parameterizations. In this work, we show
that these different descriptions for eta particle are equivalent up to some
SU(3) rotations as long as we suitably redefine the pseudo Goldstone boson
fields. We evaluate the necessary SU(3) rotations and built up explicit
expressions for redefined fields.


title: Phase diagram of the dilute magnet LiHo_xY_{1-x}F_4

abstract:
  We study the effective long-range Ising dipole model with a local exchange
interaction appropriate for the dilute magnetic compound LiHo_{x}Y_{1-x}F_4.
Our calculations yield a value of 0.12 K for the nearest neighbor exchange
interaction. Using a Monte Carlo method we calculate the phase boundary T_c(x)
between the ferromagnetic and paramagnetic phases. We demonstrate that the
experimentally observed linear decrease in T_c with dilution is not the simple
mean-field result, but a combination of the effects of fluctuations, the
exchange interaction and the hyperfine coupling. Furthermore, we find a
critical dilution x_c=0.21(2), below which there is no ordering. In agreement
with recent Monte Carlo simulations on a similar model, we find no evidence of
the experimentally observed freezing of the glassy state in our calculation. We
apply the theory of Stephen and Aharony to LiHo_{x}Y_{1-x}F_4 and find that the
theory does predict a finite-temperature freezing of the spin glass. Reasons
for the discrepancies are discussed.


title:
Probability Density of the Multipole Vectors for a Gaussian Cosmic
  Microwave Background

abstract:
  We review Maxwell's multipole vectors, and elucidate some of their
mathematical properties, with emphasis on the application of this tool to the
cosmic microwave background (CMB). In particular, for a completely random
function on the sphere (corresponding to the statistically isotropic Gaussian
model of the CMB), we derive the full probability density function of the
multipole vectors. This function is used to analyze the internal configurations
of the third-year Wilkinson Microwave Anisotropy Probe quadrupole and octopole,
and we show the observations are consistent with the Gaussian prediction. A
particular aspect is the planarity of the octopole, which we find not to be
anomalous.


title: Recursive boson system in the Cuntz algebra ${\cal O}_{\infty}$

abstract:
  Bosons and fermions are often written by elements of other algebras. M. Abe
gave a recursive realization of the boson by formal infinite sums of the
canonical generators of the Cuntz algebra ${\cal O}_{\infty}$. We show that
such formal infinite sum always makes sense on a certain dense subspace of any
permutative representation of ${\cal O}_{\infty}$. In this meaning, we can
regard as if the algebra ${\cal B}$ of bosons was a unital $*$-subalgebra of
${\cal O}_{\infty}$ on a given permutative representation by keeping their
unboundedness. By this relation, we compute branching laws arising from
restrictions of representations of ${\cal O}_{\infty}$ on ${\cal B}$. For
example, it is shown that the Fock representation of ${\cal B}$ is given as the
restriction of the standard representation of ${\cal O}_{\infty}$ on ${\cal
B}$.


title:
Conformal dynamics in gauge theories via non-perturbative
  renormalization group

abstract:
  The dynamics at the IR fixed point realized in the $SU(N_c)$ gauge theories
with massless Dirac fermions is studied by means of the non-perturbative
renormalization group. The analysis includes the IR fixed points with
non-trivial Yukawa couplings. The renormalization properties of the scalar
field are also discussed and it is shown that hierarchical mass scale may be
allowed without intense fine-tuning due to a large anomalous dimension.


title:
Nonfrustrated magnetoelectric with incommensurate magnetic order in
  magnetic field

abstract:
  We discuss a model nonfrustrated magnetoelectric in which strong enough
magnetoelectric coupling produces incommensurate magnetic order leading to
ferroelectricity. Properties of the magnetoelectric in magnetic field directed
perpendicular to wave vector describing the spin helix are considered in
detail. Analysis of classical energy shows that in contrast to naive
expectation the onset of ferroelectricity takes place at a field $H_{c1}$ that
is lower than the saturation field $H_{c2}$. One has $H_{c1}=H_{c2}$ at strong
enough magnetoelectric coupling. We show that at H=0 the ferroelectricity
appears at $T=T_{FE}<T_N$. Qualitative discussion of phase diagram in $H-T$
plane is presented within mean field approach.


title: Complementarity, distillable secret key, and distillable entanglement

abstract:
  We consider controllability of two conjugate observables Z and X by two
parties with classical communication. The ability is specified by two
alternative tasks, (i) agreement on Z and (ii) preparation of an eigenstate of
X with use of an extra communication channel. We prove that their feasibility
is equivalent to that of key distillation if the extra channel is quantum, and
to that of entanglement distillation if it is classical. This clarifies the
distinction between two entanglement measures, distillable key and distillable
entanglement.


title: An Automated Evaluation Metric for Chinese Text Entry

abstract:
  In this paper, we propose an automated evaluation metric for text entry. We
also consider possible improvements to existing text entry evaluation metrics,
such as the minimum string distance error rate, keystrokes per character, cost
per correction, and a unified approach proposed by MacKenzie, so they can
accommodate the special characteristics of Chinese text. Current methods lack
an integrated concern about both typing speed and accuracy for Chinese text
entry evaluation. Our goal is to remove the bias that arises due to human
factors. First, we propose a new metric, called the correction penalty (P),
based on Fitts' law and Hick's law. Next, we transform it into the approximate
amortized cost (AAC) of information theory. An analysis of the AAC of Chinese
text input methods with different context lengths is also presented.


title: Quantum storage on subradiant states in an extended atomic ensemble

abstract:
  A scheme for coherent manipulation of collective atomic states is developed
such that total subradiant states, in which spontaneous emission is suppressed
into all directions due to destructive interference between neighbor atoms, can
be created in an extended atomic ensemble. The optimal conditions for creation
of such states and suitability of them for quantum storage are discussed. It is
shown that in order to achieve the maximum signal-to-noise ratio the shape of a
light pulse to be stored and reconstructed using a homogeneously broadened
absorbtion line of an atomic system should be a time-reversed regular part of
the response function of the system. In the limit of high optical density, such
pulses allow one to prepare collective subradiant atomic states with near flat
spatial distribution of the atomic excitation in the medium.


title: Different vacua in 2HDM

abstract:
  We discuss the extrema of the Two Higgs Doublet Model with different physical
properties. We have found necessary and sufficient conditions for realization
of the extrema with different properties as the vacuum state of the model. We
found explicit equations for extremum energies via parameters of potential if
it has explicitly CP conserving form. These equations allow to pick out
extremum with lower energy -- vacuum state and to look for change of extrema
(phase transitions) with the variation of parameters of potential. Our goal is
to find general picture here to apply it for description of early Universe.


title: On the Development of Text Input Method - Lessons Learned

abstract:
  Intelligent Input Methods (IM) are essential for making text entries in many
East Asian scripts, but their application to other languages has not been fully
explored. This paper discusses how such tools can contribute to the development
of computer processing of other oriental languages. We propose a design
philosophy that regards IM as a text service platform, and treats the study of
IM as a cross disciplinary subject from the perspectives of software
engineering, human-computer interaction (HCI), and natural language processing
(NLP). We discuss these three perspectives and indicate a number of possible
future research directions.


title:
AC Josephson current and supercurrent noise through one-dimensional
  correlated electron systems

abstract:
  AC Josephson effect in one-dimensional Tomonaga-Luttinger liquid (TLL)
adiabatically connected to superconducting electrodes is theoretically
investigated. It is found that density fluctuations due to repulsive
electron-electron interactions in TLL inhibit Josephson oscillations, whereas
they do not affect time-independent current part. We also show that the
fluctuations reduce supercurrent noise caused by multiple Andreev reflections.
This indicates that the quantum fluctuations in TLL disturb the superconducting
phase coherence spreading across the junction.


title:
The Orbifolds of Permutation-Type as Physical String Systems at
  Multiples of c=26 IV. Orientation Orbifolds Include Orientifolds

abstract:
  In this fourth paper of the series, I clarify the somewhat mysterious
relation between the large class of {\it orientation orbifolds} (with twisted
open-string CFT's at $\hat c=52$) and {\it orientifolds} (with untwisted open
strings at $c=26$), both of which have been associated to division by
world-sheet orientation-reversing automorphisms. In particular -- following a
spectral clue in the previous paper -- I show that, even as an {\it interacting
string system}, a certain half-integer-moded orientation orbifold-string system
is in fact equivalent to the archetypal orientifold. The subtitle of this
paper, that orientation orbifolds include and generalize standard orientifolds,
then follows because there are many other orientation orbifold-string systems
-- with higher fractional modeing -- which are not equivalent to untwisted
string systems.


title: Dbar-N interaction from meson-exchange and quark-gluon dynamics

abstract:
  We investigate the Dbar-N interaction at low energies using a meson-exchange
model supplemented with a short-distance contribution from one-gluon-exchange.
The model is developed in close analogy to the meson-exchange KN interaction of
the Juelich group utilizing SU(4) symmetry constraints. The main ingredients of
the interaction are provided by vector meson (rho, omega) exchange and
higher-order box diagrams involving D*N, D\Delta, and D*\Delta intermediate
states. The short range part is assumed to receive additional contributions
from genuine quark-gluon processes. The predicted cross sections for Dbar-N for
excess energies up to 150 MeV are of the same order of magnitude as those for
KN but with average values of around 20 mb, roughly a factor two larger than
for the latter system. It is found that the omega-exchange plays a very
important role. Its interference pattern with the rho-exchange, which is
basically fixed by the assumed SU(4) symmetry, clearly determines the
qualitative features of the Dbar-N interaction -- very similiar to what happens
also for the KN system.


title:
Unified quantum invariants and their refinements for homology 3-spheres
  with 2-torsion

abstract:
  For every rational homology 3-sphere with 2-torsion only we construct a
unified invariant (which takes values in a certain cyclotomic completion of a
polynomial ring), such that the evaluation of this invariant at any odd root of
unity provides the SO(3) Witten-Reshetikhin-Turaev invariant at this root and
at any even root of unity the SU(2) quantum invariant. Moreover, this unified
invariant splits into a sum of the refined unified invariants dominating spin
and cohomological refinements of quantum SU(2) invariants. New results on the
Ohtsuki series and the integrality of quantum invariants are the main
applications of our construction.


title: Statefinder Parameters for Five-Dimensional Cosmology

abstract:
  We study the statefinder parameter in the five-dimensional big bounce model,
and apply it to differentiate the attractor solutions of quintessence and
phantom field. It is found that the evolving trajectories of these two
attractor solutions in the statefinder parameters plane are quite different,
and that are different from the statefinder trajectories of other dark energy
models.


title: Quantum Hall ferromagnetism in graphene: a SU(4) bosonization approach

abstract:
  We study the quantum Hall effect in graphene at filling factors \nu = 0 and
\nu = \pm, concentrating on the quantum Hall ferromagnetic regime, within a
non-perturbative bosonization formalism. We start by developing a bosonization
scheme for electrons with two discrete degrees of freedom (spin-1/2 and
pseudospin-1/2) restricted to the lowest Landau level. Three distinct phases
are considered, namely the so-called spin-pseudospin, spin, and pseudospin
phases. The first corresponds to a quarter-filled (\nu =-1) while the others to
a half-filled (\nu = 0) lowest Landau level. In each case, we show that the
elementary neutral excitations can be treated approximately as a set of
n-independent kinds of boson excitations. The boson representation of the
projected electron density, the spin, pseudospin, and mixed spin-pseudospin
density operators are derived. We then apply the developed formalism to the
effective continuous model, which includes SU(4) symmetry breaking terms,
recently proposed by Alicea and Fisher. For each quantum Hall state, an
effective interacting boson model is derived and the dispersion relations of
the elementary excitations are analytically calculated. We propose that the
charged excitations (quantum Hall skyrmions) can be described as a coherent
state of bosons. We calculate the semiclassical limit of the boson model
derived from the SU(4) invariant part of the original fermionic Hamiltonian and
show that it agrees with the results of Arovas and co-workers for SU(N) quantum
Hall skyrmions. We briefly discuss the influence of the SU(4) symmetry breaking
terms in the skyrmion energy.


title: Hamiltonian Graphs and the Traveling Salesman Problem

abstract:
  A new characterisation of Hamiltonian graphs using f-cutset matrix is
proposed. A new exact polynomial time algorithm for the travelling salesman
problem (TSP) based on this new characterisation is developed. We then define
so called ordered weighted adjacency list for given weighted complete graph and
proceed to the main result of the paper, namely, the exact algorithm based on
utilisation of ordered weighted adjacency list and the simple properties that
any path or circuit must satisfy. This algorithm performs checking of
sub-lists, containing (p-1) entries (edge pairs) for paths and p entries (edge
pairs) for circuits, chosen from ordered adjacency list in a well defined
sequence to determine exactly the shortest Hamiltonian path and shortest
Hamiltonian circuit in a weighted complete graph of p vertices. The procedure
has intrinsic advantage of landing on the desired solution in quickest possible
time and even in worst case in polynomial time. A new characterisation of
shortest Hamiltonian tour for a weighted complete graph satisfying triangle
inequality (i.e. for tours passing through every city on a realistic map of
cities where cities can be taken as points on a Euclidean plane) is also
proposed. Finally, we propose a classical algorithm for unstructured search and
also three new quantum algorithms for unstructured search which exponentially
speed up the searching ability in the unstructured database and discuss its
effect on the NP-Complete problems.


title:
Superconducting gap variations induced by structural supermodulation in
  BSCCO

abstract:
  We discuss the possibility that the strain field introduced by the structural
supermodulation in Bi-2212 and certain other cuprate materials may modulate the
superconducting pairing interaction. We calculate the amplitude of this effect,
visible in scanning tunneling spectroscopy experiments, and thereby relate a
change in the local superconducting gap with the change in the local dopant
displacements induced by the supermodulation. In principle, since this
modulation is periodic, sufficiently accurate x-ray measurements or ab initio
calculations should enable one to determine which atomic displacements enhance
pairing and therefore T_c.


title: Periodicity of certain piecewise affine planar maps

abstract:
  We determine periodic and aperiodic points of certain piecewise affine maps
in the Euclidean plane. Using these maps, we prove for
$\lambda\in\{\frac{\pm1\pm\sqrt5}2,\pm\sqrt2,\pm\sqrt3\}$ that all integer
sequences $(a_k)_{k\in\mathbb Z}$ satisfying $0\le a_{k-1}+\lambda
a_k+a_{k+1}<1$ are periodic.


title: First proper motions of thin dust filaments at the Galactic Center

abstract:
  Context: L'-band (3.8 micron) images of the Galactic Center show a large
number of thin filaments in the mini-spiral, located west of the mini-cavity
and along the inner edge of the Northern Arm. One possible mechanism that could
produce such structures is the interaction of a central wind with the
mini-spiral. Additionally, we identify similar features that appear to be
associated with stars. Aims: We present the first proper motion measurements of
the thin dust filaments observed in the central parsec around SgrA* and
investigate possible mechanisms that could be responsible for the observed
motions. Methods: The observations have been carried out using the NACO
adaptive optics system at the ESO VLT. The images have been transformed to a
common coordinate system and features of interest were extracted. Then a
cross-correlation technique could be performed in order to determine the
offsets between the features with respect to their position in the reference
epoch. Results: We derive the proper motions of a number of filaments and 2
cometary shaped dusty sources close (in projection) to SgrA*. We show that the
shape and the motion of the filaments does not agree with a purely Keplerian
motion of the gas in the potential of the supermassive black hole at the
position of SgrA*. Therefore, additional mechanisms must be responsible for
their formation and motion. We argue that the properties of the filaments are
probably related to an outflow from the disk of young mass-losing stars around
SgrA*. In part, the outflow may originate from the black hole itself. We also
present some evidence and theoretical considerations that the outflow may be
collimated.


title: Virtual Photon Emission from Quark-Gluon Plasma

abstract:
  We recently proposed an empirical approach for the Landau-Pomeranchuk-Migdal
(LPM) effects in photon emission from the quark gluon plasma as a function of
photon mass. This approach was based on Generalized Emission Functions (GEF)
for photon emission, derived at a fixed temperature and strong coupling
constant. In the present work, we have extended the LPM calculations for
several temperatures and strong coupling strengths. The integral equations for
(${\bf \tilde{f}(\tilde{p}_\perp)}$) and ($\tilde{g}({\bf \tilde{p}_\perp})$)
are solved by the iterations method for the variable set
\{$p_0,q_0,Q^2,T,\alpha_s$\}, considering bremsstrahlung and $\bf aws$
processes. We generalize the dynamical scaling variables, $x_T$, $x_L$, for
bremsstrahlung and {\bf aws} processes which are now functions of variables
$p_0,q_0,Q^2,T,\alpha_s$. The GEF introduced earlier, $g^b_T$, $g^a_T$,
$g^b_L$, $g^a_L$, are also generalized for any temperatures and coupling
strengths. From this, the imaginary part of the photon polarization tensor as a
function of photon mass and energy can be calculated as a one dimensional
integral over these GEF and parton distribution functions in the plasma.
However, for phenomenological studies of experimental data, one needs a simple
empirical formula without involving parton momentum integrations. Therefore, we
present a phenomenological formula for imaginary photon polarization tensor as
a function of \{$q_0,Q^2,T,\alpha_s$\} that includes bremsstrahlung and $\bf
aws$ mechanisms along with LPM effects.


title: Optimal time evolution in (non)hermitian quantum mechanics

abstract: This paper has been withdrawn by the author


title: HD97048: a closer look to the disk

abstract:
  Aims: Today, large ground-based instruments, like VISIR on the VLT, providing
diffraction-limited (about 0.3 arcsec) images in the mid-infrared where strong
PAH features appear enable us to see the flaring structure of the disks around
Herbig Ae stars.
  Although great progress has been made in modelling the disk with radiative
transfer models able to reproduce the spectral energy distribution (SED) of
Herbig Ae stars, the constraints brought by images have not been yet fully
exploited. Here, we are interested in checking if these new observational
imaging constraints can be accounted for by predictions based on existing
models of passive centrally irradiated hydrostatic disks made to fit the SEDs
of the Herbig Ae stars.
  Methods: The images taken by VISIR in the 8.6 and 11.3 microns aromatic
features reveal a large flaring disk around HD97048 inclined to the line of
sight. In order to analyse the spatial distribution of these data, we use a
disk model which includes the most up to date understanding of disk structure
and physics around Herbig Ae stars with grains in thermal equilibrium in
addition to transiently-heated PAHs.
  Results: We compare the observed spatial distribution of the PAH emission
feature and the adjacent continuum emission with predictions based on existing
full disk models. Both SED and spatial distribution are in very good agreement
with the model predictions for common disk parameters.
  Conclusions: We take the general agreement between observations and
predictions as a strong support for the physical pictures underlying our flared
disk model.


title: Holographic Chaplygin gas model

abstract:
  In this paper we consider a correspondence between the holographic dark
energy density and Chaplygin gas energy density in FRW universe. Then we
reconstruct the potential and the dynamics of the scalar field which describe
the Chaplygin cosmology.


title:
Optically tuned dimensionality crossover in photocarrier-doped
  SrTiO$_3$: onset of weak localization

abstract:
  We report magnetotransport properties of photogenerated electrons in undoped
SrTiO$_3$ single crystals under ultraviolet illumination down to 2 K. By tuning
the light intensity, the steady state carrier density can be controlled, while
tuning the wavelength controls the effective electronic thickness by modulating
the optical penetration depth. At short wavelengths, when the sheet conductance
is close to the two-dimensional Mott minimum conductivity we have observed
critical behavior characteristic of weak localization. Negative
magnetoresistance at low magnetic field is highly anisotropic, indicating
quasi-two-dimensional electronic transport. The high mobility of photogenerated
electrons in SrTiO$_3$ allows continuous tuning of the effective electronic
dimensionality by photoexcitation.


title:
Critical properties of spherically symmetric accretion in a fractal
  medium

abstract:
  Spherically symmetric transonic accretion of a fractal medium has been
studied in both the stationary and the dynamic regimes. The stationary
transonic solution is greatly sensitive to infinitesimal deviations in the
outer boundary condition, but the flow becomes transonic and stable, when its
evolution is followed through time. The evolution towards transonicity is more
pronounced for a fractal medium than what is it for a continuum. The dynamic
approach also shows that there is a remarkable closeness between an equation of
motion for a perturbation in the flow, and the metric of an analogue acoustic
black hole. The stationary inflow solutions of a fractal medium are as much
stable under the influence of linearised perturbations, as they are for the
fluid continuum.


title: IGR J16194-2810: a new symbiotic X-ray binary

abstract:
  We here report on the multiwavelength study which led us to the
identification of X-ray source IGR J16194-2810 as a new Symbiotic X-ray Binary
(SyXB), that is, a rare type of Low Mass X-ray Binary (LMXB) composed of a
M-type giant and a compact object. Using the accurate X-ray position allowed by
Swift/XRT data, we pinpointed the optical counterpart, a M2 III star. Besides,
the combined use of the spectral information afforded by XRT and INTEGRAL/IBIS
shows that the 0.5-200 keV spectrum of this source can be described with an
absorbed Comptonization model, usually found in LMXBs and, in particular, in
SyXBs. No long-term (days to months) periodicities are detected in the IBIS
data. The time coverage afforded by XRT reveals shot-noise variability typical
of accreting Galactic X-ray sources, but is not good enough to explore the
presence of X-ray short-term (seconds to hours) oscillations in detail. By
using the above information, we infer important parameters for this source such
as its distance (about 3.7 kpc) and X-ray luminosity (about 1.4e35 erg/s in the
0.5-200 keV band), and we give a description for this system (typical of SyXBs)
in which a compact object (possibly a neutron star) accretes from the wind of
its M-type giant companion. We also draw some comparisons between IGR
J16194-2810 and other sources belonging to this subclass, finding that this
object resembles SyXBs 4U 1700+24 and 4U 1954+31.


title: The Complexity of Weighted Boolean #CSP

abstract:
  This paper gives a dichotomy theorem for the complexity of computing the
partition function of an instance of a weighted Boolean constraint satisfaction
problem. The problem is parameterised by a finite set F of non-negative
functions that may be used to assign weights to the configurations (feasible
solutions) of a problem instance. Classical constraint satisfaction problems
correspond to the special case of 0,1-valued functions. We show that the
partition function, i.e. the sum of the weights of all configurations, can be
computed in polynomial time if either (1) every function in F is of ``product
type'', or (2) every function in F is ``pure affine''. For every other fixed
set F, computing the partition function is FP^{#P}-complete.


title:
Dynamics of Quantum Dot Nuclear Spin Polarization Controlled by a Single
  Electron

abstract:
  We present an experimental study of the dynamics underlying the buildup and
decay of dynamical nuclear spin polarization in a single semiconductor quantum
dot. Our experiment shows that the nuclei can be polarized on a time scale of a
few milliseconds, while their decay dynamics depends drastically on external
parameters. We show that a single electron can very efficiently depolarize the
nuclear spins and discuss two processes that can cause this depolarization.
Conversely, in the absence of a quantum dot electron, the lifetime of nuclear
spin polarization is on the time scale of a second, most likely limited by the
non-secular terms of the nuclear dipole-dipole interaction. We can further
suppress this depolarization rate by 1-2 orders of magnitude by applying an
external magnetic field exceeding 1 mT.


title: Flow instabilities of magnetic flux tubes II. Longitudinal flow

abstract:
  Flow-induced instabilities are relevant for the storage and dynamics of
magnetic fields in stellar convection zones and possibly also in other
astrophysical contexts. We continue the study started in the first paper of
this series by considering the stability properties of longitudinal flows along
magnetic flux tubes. A linear stability analysis was carried out to determine
criteria for the onset of instability in the framework of the approximation of
thin magnetic flux tubes. In the non-dissipative case, we find Kelvin-Helmholtz
instability for flow velocities exceeding a critical speed that depends on the
Alfv{\'e}n speed and on the ratio of the internal and external densities.
Inclusion of a friction term proportional to the relative transverse velocity
leads to a friction-driven instability connected with backward (or negative
energy) waves. We discuss the physical nature of this instability. In the case
of a stratified external medium, the Kelvin-Helmholtz instability and the
friction-driven instability can set in for flow speeds significantly lower than
the Alfv{\'e}n speed. Dissipative effects can excite flow-driven instability
below the thresholds for the Kelvin-Helmholtz and the undulatory (Parker-type)
instabilities. This may be important for magnetic flux storage in stellar
convection zones and for the stability of astrophysical jets.


title: Improving Estimates of Monotone Functions by Rearrangement

abstract:
  Suppose that a target function is monotonic, namely, weakly increasing, and
an original estimate of the target function is available, which is not weakly
increasing. Many common estimation methods used in statistics produce such
estimates. We show that these estimates can always be improved with no harm
using rearrangement techniques: The rearrangement methods, univariate and
multivariate, transform the original estimate to a monotonic estimate, and the
resulting estimate is closer to the true curve in common metrics than the
original estimate. We illustrate the results with a computational example and
an empirical example dealing with age-height growth charts.


title:
Characterizing group $C^\ast$-algebras through their unitary groups: the
  Abelian case

abstract:
  We study to what extent group $C^\ast$-algebras are characterized by their
unitary groups. A complete characterization of which Abelian group
$C^\ast$-algebras have isomorphic unitary groups is obtained. We compare these
results with other unitary-related invariants of $C^\ast(\Gamma)$, such as the
$K$-theoretic $K_1(C^\ast(\Gamma))$ and find that $C^\ast$-algebras of
nonisomorphic torsion-free Abelian groups may have isomorphic $K_1$-groups, in
sharp contrast with the well-known fact that $C^\ast(\Gamma)$ (even $\Gamma$)
is characterized by the topological group structure of its unitary group when
$\Gamma $ is torsion-free and Abelian.


title: Descent Relations in Cubic Superstring Field Theory

abstract:
  The descent relations between string field theory (SFT) vertices are
characteristic relations of the operator formulation of SFT and they provide
self-consistency of this theory. The descent relations <V_2|V_1> and <V_3|V_1>
in the NS fermionic string field theory in the kappa and discrete bases are
established. Different regularizations and schemes of calculations are
considered and relations between them are discussed.


title:
Thermodynamics of system with density- and/or temperature-dependent mass
  particles

abstract:
  The thermodynamics with medium effects expressed by the dispersion relation
of the temperature and density dependent particle mass is studied. Many
previous treatments have been reviewed. A new thermodynamical treatment based
on the equilibrium state is suggested. Employing the quark mass density- and
temperature-dependent model, the discrepancies between our treatment and others
are addressed.


title: Mittag-Leffler conditions on modules

abstract:
  We study Mittag-Leffler conditions on modules providing relative versions of
classical results by Raynaud and Gruson. We then apply our investigations to
several contexts. First of all, we give a new argument for solving the Baer
splitting problem. Moreover, we show that modules arising in cotorsion pairs
satisfy certain Mittag-Leffler conditions. In particular, this implies that
tilting modules satisfy a useful finiteness condition over their endomorphism
ring. In the final section, we focus on a special tilting cotorsion pair
related to the pure-semisimplicity conjecture.


title:
Electroproduction of kaons from the proton in a Regge-plus-resonance
  approach

abstract:
  We present a Regge-plus-resonance (RPR) description of the p(e,e'K^+)Y
processes (Y=\Lambda,\Sigma^0) in the resonance region. The background
contributions to the RPR amplitude are constrained by the high-energy p(\gamma,
K^+)Y data. As a result, the number of free model parameters in the resonance
region is considerably reduced compared to typical effective-Lagrangian
approaches. We compare a selection of RPR model variants, originally
constructed to describe $KY$ photoproduction, with the world electroproduction
database. The electromagnetic form factors of the intermediate N^*s and
$\Delta^*s are computed in the Bonn constituent-quark model. With this input,
we find a reasonable description of the p(e,e'K^+)Y data without adding or
readjusting any parameters. It is demonstrated that the electroproduction
response functions are extremely useful for fine-tuning both the background and
resonant contributions to the reaction dynamics.


title:
Analytically solvable model of a driven system with quenched dichotomous
  disorder

abstract:
  We perform a time-dependent study of the driven dynamics of overdamped
particles which are placed in a one-dimensional, piecewise linear random
potential. This set-up of spatially quenched disorder then exerts a dichotomous
varying random force on the particles. We derive the path integral
representation of the resulting probability density function for the position
of the particles and transform this quantity of interest into the form of a
Fourier integral. In doing so, the evolution of the probability density can be
investigated analytically for finite times. It is demonstrated that the
probability density contains both a $\delta$-singular contribution and a
regular part. While the former part plays a dominant role at short times, the
latter rules the behavior at large evolution times. The slow approach of the
probability density to a limiting Gaussian form as time tends to infinity is
elucidated in detail.


title: Reconstruction Algebras of Type A

abstract:
  We introduce a new class of algebras, called reconstruction algebras, and
present some of their basic properties. These non-commutative rings dictate in
every way the process of resolving the Cohen-Macaulay singularities C^2/G where
G is a finite small cyclic subgroup of GL(2,C).


title: On The Spectrum of Yang-Mills Theory in 2+1 Dimensions, Analytically

abstract:
  We review our recent work on the glueball spectrum of pure Yang-Mills theory
in 2+1 dimensions. The calculations make use of Karabali-Nair corner variables
in the Hamiltonian formalism, and involve a determination of the leading form
of the ground-state wavefunctional.


title: Large scale and large period limits of symmetric calorons

abstract:
  We construct SU(2) calorons, with non-trivial holonomy, instanton charge 2
and magnetic charge 0 or -1; these calorons have two constituent monopoles,
with charges (2,2) or (2,1). Our calorons are U(1)-symmetric and are
constructed via the Nahm transform. They fall into distinct families which can
be classified using representation theory. We consider large scale and large
period limits of these calorons; in particular, the large scale limit may be a
monopole, or a caloron with different topological charges.


title: A weighted graph problem from commutative algebra

abstract:
  We give an especially simple proof of a theorem in graph theory that forms
the key part of the solution to a problem in commutative algebra, on how to
characterize the integral closure of a polynomial ring generated by quadratic
monomials.


title:
Quantification of discreteness effects in cosmological N-body
  simulations: II. Evolution up to shell crossing

abstract:
  We apply a recently developed perturbative formalism which describes the
evolution under their self-gravity of particles displaced from a perfect
lattice to quantify precisely, up to shell crossing, the effects of
discreteness in dissipationless cosmological N-body simulations. We give simple
expressions, explicitly dependent on the particle density, for the evolution of
power in each mode as a function of red-shift. For typical starting red-shifts
the effect of finite particle number is to {\it slow down} slightly the growth
of power compared to that in the fluid limit (e.g. by about ten percent at half
the Nyquist frequency), and to induce also dispersion in the growth as a
function of direction at a comparable level. In the limit that the initial
red-shift tends to infinity, at fixed particle density, the evolution in fact
diverges from that in the fluid limit (described by the Zeldovich
approximation). Contrary to widely held belief, this means that a simulation
started at a red-shift much higher than the red-shift of shell crossing
actually gives a worse, rather than a better, result. We also study how these
effects are modified when there is a small-scale regularization of the
gravitational force. We show that such a smoothing may reduce the anisotropy of
the discreteness effects, but it then {\it increases} their average effect.
This behaviour illustrates the fact that the discreteness effects described
here are distinct from those usually considered in this context, due to
two-body collisions. Indeed the characteristic time for divergence from the
collisionless limit is proportional to $N^{2/3}$, rather than $N/ \log N$ in
the latter case.


title: Demazure embeddings are smooth

abstract:
  We prove Brion's conjecture stating that the closure of the orbit of a
self-normalizing spherical subalgebra in the corresponding Grassmanian is
smooth


title:
Wigner functions, coherent states, one-dimensional marginal
  probabilities and uncertainty structures of Landau levels

abstract:
  Following an approach based on generating function method phase space
characteristics of Landau system are studied in the autonomous framework of
deformation quantization. Coherent state property of generating functions is
established and marginal probability densities along canonical coordinate lines
are derived. Well defined analogs of inner product, Cauchy-Bunyakowsy-Schwarz
inequality and state functional have been defined in phase space and they have
been used in analyzing the uncertainty structures. The general form of the
uncertainty relation for two real-valued functions is derived and uncertainty
products are computed in states described by Wigner functions. Minimum
uncertainty state property of the standard coherent states is presented and
uncertainty structures in the case of phase space generalized coherent states
are analyzed.


title: Constrained flow around a magnetic obstacle

abstract:
  Many practical applications exploit an external local magnetic field --
magnetic obstacle -- as an essential part of their constructions. Recently, it
has been demonstrated that the flow of an electrically conducting fluid
influenced by an external field can show several kinds of recirculation. The
present paper reports a 3D numerical study whose some results are compared with
an experiment about such a flow in a rectangular duct.


title:
Comment on ``Enhanced transmission of light through a gold film due to
  excitation of standing surface-plasmon Bloch waves"

abstract:
  The purpose of this comment is first to correct a misapprehension of the role
played by composite wave diffraction on surface-wave generation at
subwavelength structures and second to point out that periodic Bloch structures
are unnecessary for the efficient production of the surface plasmon polariton
(SPP) guided mode either as traveling or standing waves. Guided surface waves
originate from simple slit or groove edges illuminated under normal incidence,
and one-dimensional (1-D) surface cavities from these standing waves are easily
realized.


title: Statistical mechanics of complex networks

abstract:
  The science of complex networks is a new interdisciplinary branch of science
which has arisen recently on the interface of physics, biology, social and
computer sciences, and others. Its main goal is to discover general laws
governing the creation and growth as well as processes taking place on
networks, like e.g. the Internet, transportation or neural networks. It turned
out that most real-world networks cannot be simply reduced to a compound of
some individual components. Fortunately, the statistical mechanics, being one
of pillars of modern physics, provides us with a very powerful set of tools and
methods for describing and understanding these systems. In this thesis, we
would like to present a consistent approach to complex networks based on
statistical mechanics, with the central role played by the concept of
statistical ensemble of networks. We show how to construct such a theory and
present some practical problems where it can be applied. Among them, we pay
attention to the problem of finite-size corrections and the dynamics of a
simple model of mass transport on networks.


title: Thin Spectrum States in Superconductors

abstract:
  We show that finite size superconductors have a spectrum of states at
extremely low energy, i.e. inside the superconducting gap. The presence of this
{\it thin spectrum} is a generic feature and related to the fact that in a
superconductor the global phase rotation symmetry is spontaneously broken. For
a strong coupling superconductor we find the spectrum by exactly solving the
Lieb-Mattis type Hamiltonian onto which the problem maps. One of the physical
consequences of the presence of thin states is that they cause quantum
decoherence in superconducting qubits of finite extent.


title:
Multimodal nested sampling: an efficient and robust alternative to MCMC
  methods for astronomical data analysis

abstract:
  In performing a Bayesian analysis of astronomical data, two difficult
problems often emerge. First, in estimating the parameters of some model for
the data, the resulting posterior distribution may be multimodal or exhibit
pronounced (curving) degeneracies, which can cause problems for traditional
MCMC sampling methods. Second, in selecting between a set of competing models,
calculation of the Bayesian evidence for each model is computationally
expensive. The nested sampling method introduced by Skilling (2004), has
greatly reduced the computational expense of calculating evidences and also
produces posterior inferences as a by-product. This method has been applied
successfully in cosmological applications by Mukherjee et al. (2006), but their
implementation was efficient only for unimodal distributions without pronounced
degeneracies. Shaw et al. (2007), recently introduced a clustered nested
sampling method which is significantly more efficient in sampling from
multimodal posteriors and also determines the expectation and variance of the
final evidence from a single run of the algorithm, hence providing a further
increase in efficiency. In this paper, we build on the work of Shaw et al. and
present three new methods for sampling and evidence evaluation from
distributions that may contain multiple modes and significant degeneracies; we
also present an even more efficient technique for estimating the uncertainty on
the evaluated evidence. These methods lead to a further substantial improvement
in sampling efficiency and robustness, and are applied to toy problems to
demonstrate the accuracy and economy of the evidence calculation and parameter
estimation. Finally, we discuss the use of these methods in performing Bayesian
object detection in astronomical datasets.


title: QMC: A Model Checker for Quantum Systems

abstract:
  We introduce a model-checking tool intended specially for the analysis of
quantum information protocols. The tool incorporates an efficient
representation of a certain class of quantum circuits, namely those expressible
in the so-called stabiliser formalism. Models of protocols are described using
a simple, imperative style simulation language which includes commands for the
unitary operators in the Clifford group as well as classical integer and
boolean variables. Formulas for verification are expressed using a subset of
quantum computational tree logic (QCTL). The model-checking procedure treats
quantum measurements as the source of non-determinism, leading to multiple
protocol runs, one for each outcome. Verification is performed for each run.


title: A multivariate approach to heavy flavour tagging with cascade training

abstract:
  This paper compares the performance of artificial neural networks and boosted
decision trees, with and without cascade training, for tagging b-jets in a
collider experiment. It is shown, using a Monte Carlo simulation of $WH \to
l\nu q\bar{q}$ events, that for a b-tagging efficiency of 50%, the light jet
rejection power given by boosted decision trees without cascade training is
about 55% higher than that given by artificial neural networks. The cascade
training technique can improve the performance of boosted decision trees and
artificial neural networks at this b-tagging efficiency level by about 35% and
80% respectively. We conclude that the cascade trained boosted decision trees
method is the most promising technique for tagging heavy flavours at collider
experiments.


title:
Softening of the equation of state of matter at large densities and
  temperatures: chiral symmetry restoration vs. quark deconfinement

abstract:
  We discuss two models for describing the behavior of matter at large
densities and intermediate temperatures. In both models a softening of the
equation of state takes place due to the appearance of new degrees of freedom.
The first is a hadronic model in which the softening is due to chiral symmetry
restoration. In the second model the softening is associated with the formation
of clusters of quarks in the mixed phase. We show that both models allow a
significant softening but, in the first case the bulk modulus is mainly
dependent on the density, while in the mixed phase model it also strongly
depends on the temperature. We also show that the bulk modulus is not vanishing
in the mixed phase due to the presence of two conserved charges, the baryon and
the isospin one. Only in a small region of densities and temperatures the
incompressibility becomes extremely small. Finally we compare our results with
recent analysis of heavy ion collisions at intermediate energies.


title: Network statistics on early English Syntax: Structural criteria

abstract:
  This paper includes a reflection on the role of networks in the study of
English language acquisition, as well as a collection of practical criteria to
annotate free-speech corpora from children utterances. At the theoretical
level, the main claim of this paper is that syntactic networks should be
interpreted as the outcome of the use of the syntactic machinery. Thus, the
intrinsic features of such machinery are not accessible directly from (known)
network properties. Rather, what one can see are the global patterns of its use
and, thus, a global view of the power and organization of the underlying
grammar. Taking a look into more practical issues, the paper examines how to
build a net from the projection of syntactic relations. Recall that, as opposed
to adult grammars, early-child language has not a well-defined concept of
structure. To overcome such difficulty, we develop a set of systematic criteria
assuming constituency hierarchy and a grammar based on lexico-thematic
relations. At the end, what we obtain is a well defined corpora annotation that
enables us i) to perform statistics on the size of structures and ii) to build
a network from syntactic relations over which we can perform the standard
measures of complexity. We also provide a detailed example.


title: The end of the "Empty Field" epoch in optical identifications

abstract:
  In order to obtain more comprehensive information about an celestial object,
the radio image must be identified with the optical one. Many years the
identification process is carried out with the coordinate coincidence criteria,
which leads to abundant misidentifications and "empty field" in optics for the
radio sources. For this reason significant part of radio sources do not have
identifications in optic. In present paper we consider the radio refraction in
the Galaxy, which significantly changes the coordinates of radio sources if
compared with the optical one. By taking into account the radio refraction, the
major number of the radio sources can be successfully identified with the
optical objects.


title: Blow-up of the hyperbolic Burgers equation

abstract:
  The memory effects on microscopic kinetic systems have been sometimes
modelled by means of the introduction of second order time derivatives in the
macroscopic hydrodynamic equations. One prototypical example is the hyperbolic
modification of the Burgers equation, that has been introduced to clarify the
interplay of hyperbolicity and nonlinear hydrodynamic evolution. Previous
studies suggested the finite time blow-up of this equation, and here we present
a rigorous proof of this fact.


title: Maximal C*-algebras of quotients and injective envelopes of C*-algebras

abstract:
  A new C*-enlargement of a C*-algebra $A$ nested between the local multiplier
algebra $M_{\text{loc}}(A)$ of $A$ and its injective envelope $I(A)$ is
introduced. Various aspects of this maximal C*-algebra of quotients,
$Q_{\text{max}}(A)$, are studied, notably in the setting of AW*-algebras. As a
by-product we obtain a new example of a type I C*-algebra $A$ such that
$M_{\text{loc}}(M_{\text{loc}}(A))\ne M_{\text{loc}}(A)$.


title: Nuclear p_t broadening at HERMES

abstract:
  The first direct measurement of p_t-broadening effects in cold nuclear matter
has been studied as a function of several kinematic variables for different
hadron types. The data have been accumulated by the HERMES experiment at DESY,
in which the HERA 27.6 GeV lepton beam scattered off several nuclear gas
targets.


title:
Shear-strain-induced Spatially Varying Super-lattice Structures on
  Graphite studied by STM

abstract:
  We report on the Scanning Tunneling Microscope (STM) observation of linear
fringes together with spatially varying super-lattice structures on (0001)
graphite (HOPG) surface. The structure, present in a region of a layer bounded
by two straight carbon fibers, varies from a hexagonal lattice of 6nm
periodicity to nearly a square lattice of 13nm periodicity. It then changes
into a one-dimensional (1-D) fringe-like pattern before relaxing into a
pattern-free region. We attribute this surface structure to a shear strain
giving rise to a spatially varying rotation of the affected graphite layer
relative to the bulk substrate. We propose a simple method to understand these
moire patterns by looking at the fixed and rotated lattices in the Fourier
transformed k-space. Using this approach we can reproduce the spatially varying
2-D lattice as well as the 1-D fringes by simulation. The 1-D fringes are found
to result from a particular spatial dependence of the rotation angle.


title: Second discontinuity in the specific heat of two-phase superconductors

abstract:
  The recently proposed theoretical model of superconductors endowed with two
distinct superconducting phases and critical temperatures is further analyzed
by introducing two distinct order parameters, described by two scalar fields
which condensate at different temperatures. We find some deviations in basic
thermodynamical quantities with respect to the Ginzburg-Landau one-phase
superconductors. In particular, by contrast to the usual case where only one
jump in specific heat takes place at the normal-superconductor transition
temperature, we actually predict an additional discontinuity for C_V when
passing from a superconducting phase to the other one.


title:
Efficient model chemistries for peptides. I. Split-valence Gaussian
  basis sets and the heterolevel approximation in RHF and MP2

abstract:
  We present an exhaustive study of more than 250 ab initio potential energy
surfaces (PESs) of the model dipeptide HCO-L-Ala-NH2. The model chemistries
(MCs) used are constructed as homo- and heterolevels involving possibly
different RHF and MP2 calculations for the geometry and the energy. The basis
sets used belong to a sample of 39 selected representants from Pople's
split-valence families, ranging from the small 3-21G to the large
6-311++G(2df,2pd). The reference PES to which the rest are compared is the
MP2/6-311++G(2df,2pd) homolevel, which, as far as we are aware, is the more
accurate PES of a dipeptide in the literature. The aim of the study presented
is twofold: On the one hand, the evaluation of the influence of polarization
and diffuse functions in the basis set, distinguishing between those placed at
1st-row atoms and those placed at hydrogens, as well as the effect of different
contraction and valence splitting schemes. On the other hand, the investigation
of the heterolevel assumption, which is defined here to be that which states
that heterolevel MCs are more efficient than homolevel MCs. The heterolevel
approximation is very commonly used in the literature, but it is seldom
checked. As far as we know, the only tests for peptides or related systems,
have been performed using a small number of conformers, and this is the first
time that this potentially very economical approximation is tested in full
PESs. In order to achieve these goals, all data sets have been compared and
analyzed in a way which captures the nearness concept in the space of MCs.


title:
Existence and Number of Solutions of Diophantine Quadratic Equations
  with Two Unknowns in $Z$ and $N$

abstract:
  In this short note we study the existence and number of solutions in the set
of integers ($Z$) and in the set of natural numbers ($N$) of Diopahntine
Equations of second degree with two variables of the general form
$ax^2-by^2=c$.


title: Ion condensation on charged patterned surfaces

abstract:
  We study ion condensation onto a patterned surface of alternating charges.
The competition between self-energy and ion-surface interactions leads to the
formation of ionic crystalline structures at low temperatures. We consider
different arrangements of underlying ionic crystals, including single ion
adsorption, as well as the formation of dipoles at the interface between
charged domains. Molecular dynamic simulation illustrates existence of single
and mixed phases. Our results contribute to understanding pattern recognition,
and molecular separation and synthesis near patterned surfaces.


title:
Gamma-Ray Burst Afterglows as Probes of Environment and Blastwave
  Physics II: the Distribution of p and Structure of the Circumburst Medium

abstract:
  We constrain blastwave parameters and the circumburst media of a subsample of
ten BeppoSAX Gamma-Ray Bursts. For this sample we derive the values of the
injected electron energy distribution index, p, and the density structure index
of the circumburst medium, k, from simultaneous spectral fits to their X-ray,
optical and nIR afterglow data. The spectral fits have been done in count space
and include the effects of metallicity, and are compared with the previously
reported optical and X-ray temporal behaviour. Using the blastwave model and
some assumptions which include on-axis viewing and standard jet structure,
constant blastwave energy and no evolution of the microphysical parameters, we
find a mean value of p for the sample as a whole of 2.04 +0.02/-0.03. A
statistical analysis of the distribution demonstrates that the p values in this
sample are inconsistent with a single universal value for p at the 3-sigma
level or greater, which has significant implications for particle acceleration
models. This approach provides us with a measured distribution of circumburst
density structures rather than considering only the cases of k=0 (homogeneous)
and k=2 (wind-like). We find five GRBs for which k can be well constrained, and
in four of these cases the circumburst medium is clearly wind-like. The fifth
source has a value of 0<k<1, consistent with a homogeneous circumburst medium.


title: A holographic proof of the strong subadditivity of entanglement entropy

abstract:
  When a quantum system is divided into subsystems, their entanglement
entropies are subject to an inequality known as "strong subadditivity". For a
field theory this inequality can be stated as follows: given any two regions of
space $A$ and $B$, $S(A) + S(B) \ge S(A \cup B) + S(A \cap B)$. Recently, a
method has been found for computing entanglement entropies in any field theory
for which there is a holographically dual gravity theory. In this note we give
a simple geometrical proof of strong subadditivity employing this holographic
prescription.


title: Multiparameter Riesz Commutators

abstract:
  It is shown that product BMO of Chang and Fefferman, defined on the product
of Euclidean spaces can be characterized by the multiparameter commutators of
Riesz transforms. This extends a classical one-parameter result of Coifman,
Rochberg, and Weiss, and at the same time extends the work of Lacey and
Ferguson and Lacey and Terwilleger on multiparameter commutators with Hilbert
transforms. The method of proof requires the real-variable methods throughout,
which is new in the multi-parameter context.


title: Cosmic Rays: The Second Knee and Beyond

abstract:
  We conduct a review of experimental results on Ultra-High Energy Cosmic Rays
(UHECR's) including measurements of the features of the spectrum, the
composition of the primary particle flux and the search for anisotropy in event
arrival direction. We find that while there is a general consensus on the
features in the spectrum -- the Second Knee, the Ankle, and (to a lesser
extent) the GZK Cutoff -- there is little consensus on the composition of the
primaries that accompany these features. This lack of consensus on the
composition makes interpretation of the agreed upon features problematic. There
is also little direct evidence about potential sources of UHECRs, as early
reports of arrival direction anisotropies have not been confirmed in
independent measurements.


title:
Direct Measurement of the Radius and Density of the Transiting Exoplanet
  HD 189733B with the CHARA Array

abstract:
  We have measured the angular diameter of the transiting extrasolar planet
host star HD 189733 using the CHARA O/IR interferometric array. Combining our
new angular diameter of 0.377+/-0.024 mas with the Hipparcos parallax leads to
a linear radius for the host star of 0.779+/-0.052 Rsol and a radius for the
planet of 1.19+/-0.08 RJup. Adopting the mass of the planet as derived by its
discoverers, we derive a mean density of the planet of 0.91+/-0.18 g cm-3. This
is the first determination of the diameter of an extrasolar planet through
purely direct means.


title:
Dyson Indices and Hilbert-Schmidt Separability Functions and
  Probabilities

abstract:
  A confluence of numerical and theoretical results leads us to conjecture that
the Hilbert-Schmidt separability probabilities of the 15- and 9-dimensional
convex sets of complex and real two-qubit states (representable by 4 x 4
density matrices rho) are 8/33 and 8/17, respectively. Central to our reasoning
are the modifications of two ansatze, recently advanced (quant-ph/0609006),
involving incomplete beta functions B_{nu}(a,b), where nu= (rho_{11}
rho_{44})/(rho_{22} rho_{33}). We, now, set the separability function
S_{real}(nu) propto B_{nu}(nu,1/2},2) =(2/3) (3-nu) sqrt{nu}. Then, in the
complex case -- conforming to a pattern we find, manifesting the Dyson indices
(1, 2, 4) of random matrix theory-- we take S_{complex}(nu) propto S_{real}^{2}
(nu). We also investigate the real and complex qubit-qutrit cases. Now, there
are two Bloore ratio variables, nu_{1}= (rho_{11} rho_{55})(rho_{22} rho_{44}),
nu_{2}= (rho_{22} rho_{66})(rho_{33} rho_{55}), but they appear to remarkably
coalesce into the product, eta = nu_1 nu_2 = rho_{11} \rho_{66}}{\rho_{33}
\rho_{44}}, so that the real and complex separability functions are again
univariate in nature.


title:
A Model of Late Long-Term Potentiation Simulates Aspects of Memory
  Maintenance

abstract:
  Late long-term potentiation (L-LTP) appears essential for the formation of
long-term memory, with memories at least partly encoded by patterns of
strengthened synapses. How memories are preserved for months or years, despite
molecular turnover, is not well understood. Ongoing recurrent neuronal
activity, during memory recall or during sleep, has been hypothesized to
preferentially potentiate strong synapses, preserving memories. This hypothesis
has not been evaluated in the context of a mathematical model representing
biochemical pathways important for L-LTP. I incorporated ongoing activity into
two such models: a reduced model that represents some of the essential
biochemical processes, and a more detailed published model. The reduced model
represents synaptic tagging and gene induction intuitively, and the detailed
model adds activation of essential kinases by Ca. Ongoing activity was modeled
as continual brief elevations of [Ca]. In each model, two stable states of
synaptic weight resulted. Positive feedback between synaptic weight and the
amplitude of ongoing Ca transients underlies this bistability. A tetanic or
theta-burst stimulus switches a model synapse from a low weight to a high
weight stabilized by ongoing activity. Bistability was robust to parameter
variations. Simulations illustrated that prolonged decreased activity reset
synapses to low weights, suggesting a plausible forgetting mechanism. However,
episodic activity with shorter inactive intervals maintained strong synapses.
Both models support experimental predictions. Tests of these predictions are
expected to further understanding of how neuronal activity is coupled to
maintenance of synaptic strength.


title: Codazzi spinors and globally hyperbolic manifolds with special holonomy

abstract:
  In this paper we examine the structure of Riemannian manifolds with a special
kind of Codazzi tensors. We use them to construct globally hyperbolic
Lorentzian manifolds with complete Cauchy hypersurfaces for any weakly
irreducible holonomy representation with parallel spinors, i.e. with a holonomy
group which is a semidirect product between $\R^{n-2}$ and one of $\1, SU(k),
Sp(1), G_2$ and $Spin(7)$.


title: Pion-mass dependence of three-nucleon observables

abstract:
  We use an effective field theory (EFT) which contains only short-range
interactions to study the dependence of a variety of three-nucleon observables
on the pion mass. The pion-mass dependence of input quantities in our
``pionless'' EFT is obtained from a recent chiral EFT calculation. To the order
we work at, these quantities are the 1S0 scattering length and effective range,
the deuteron binding energy, the 3S1 effective range, and the binding energy of
one three-nucleon bound state. The chiral EFT input we use has the inverse 3S1
and 1S0 scattering lengths vanishing at mpi_c=197.8577 MeV. At this
``critical'' pion mass, the triton has infinitely many excited states with an
accumulation point at the three-nucleon threshold. We compute the binding
energies of these states up to next-to-next-to-leading order in the pionless
EFT and study the convergence pattern of the EFT in the vicinity of the
critical pion mass. Furthermore, we use the pionless EFT to predict how doublet
and quartet nd scattering lengths depend on mpi in the region between the
physical pion mass and mpi=mpi_c.


title:
Self-similar and self-affine sets; measure of the intersection of two
  copies

abstract:
  Let K be a self-similar or self-affine set in R^d, let \mu be a self-similar
or self-affine measure on it, and let G be the group of affine maps,
similitudes, isometries or translations of R^d. Under various assumptions (such
as separation conditions or we assume that the transformations are small
perturbations or that K is a so called Sierpinski sponge) we prove theorems of
the following types, which are closely related to each other;
  Non-stability: There exists a constant c<1 such that for every g\in G we have
either \mu(K\cap g(K)) <c \mu(K) or K\subset g(K).
  Measure and topology: For every g\in G we have \mu(K\cap g(K)) > 0 \iff int_K
(K\cap g(K)) is nonempty (where int_K is interior relative to K).
  Extension: The measure \mu has a G-invariant extension to R^d.
  Moreover, in many situations we characterize those g's for which \mu(K\cap
g(K) > 0, and we also get results about those $g$'s for which $g(K)\su K$ or
$g(K)\supset K$ holds.


title: Quantum Effects in Black Holes from the Schwarzschild Black String?

abstract:
  The holographic conjecture for black holes localized on a 3-brane in
Randall-Sundrum braneworld models RS2 predicts the existence of a classical 5D
time dependent solution dual to a 4D evaporating black hole. After briefly
reviewing recent criticism and presenting some difficulties in the holographic
interpretation of the Gregory-Laflamme instability, we simulate some basic
features of such a solution by studying null geodesics of the Schwarzschild
black string, in particular those propagating nontrivially in the bulk, and
using holographic arguments.


title:
Divergence at low bias and down-mixing of the current noise in a
  diffusive superconductor-normal metal-superconductor junction

abstract:
  We present current noise measurements in a long diffusive
superconductor-normal-metal-superconductor junction in the low voltage regime,
in which transport can be partially described in terms of coherent multiple
Andreev reflections. We show that, when decreasing voltage, the current noise
exhibits a strong divergence together with a broad peak. We ascribe this peak
to the mixing between the ac- Josephson current and the noise of the junction
itself. We show that the junction noise corresponds to the thermal noise of a
nonlinear resistor 4kBT=R with R V = I V and no adjustable parameters.


title:
Network Growth with Preferential Attachment for High Indegree and Low
  Outdegree

abstract:
  We study the growth of a directed transportation network, such as a food web,
in which links carry resources. We propose a growth process in which new nodes
(or species) preferentially attach to existing nodes with high indegree (in
food-web language, number of prey) and low outdegree (or number of predators).
This scheme, which we call inverse preferential attachment, is intended to
maximize the amount of resources available to each new node. We show that the
outdegree (predator) distribution decays at least exponentially fast for large
outdegree and is continuously tunable between an exponential distribution and a
delta function. The indegree (prey) distribution is poissonian in the
large-network limit.


title: Catalan's intervals and realizers of triangulations

abstract:
  The Stanley lattice, Tamari lattice and Kreweras lattice are three remarkable
orders defined on the set of Catalan objects of a given size. These lattices
are ordered by inclusion: the Stanley lattice is an extension of the Tamari
lattice which is an extension of the Kreweras lattice. The Stanley order can be
defined on the set of Dyck paths of size $n$ as the relation of \emph{being
above}. Hence, intervals in the Stanley lattice are pairs of non-crossing Dyck
paths. In a former article, the second author defined a bijection $\Phi$
between pairs of non-crossing Dyck paths and the realizers of triangulations
(or Schnyder woods). We give a simpler description of the bijection $\Phi$.
Then, we study the restriction of $\Phi$ to Tamari's and Kreweras' intervals.
We prove that $\Phi$ induces a bijection between Tamari intervals and minimal
realizers. This gives a bijection between Tamari intervals and triangulations.
We also prove that $\Phi$ induces a bijection between Kreweras intervals and
the (unique) realizers of stack triangulations. Thus, $\Phi$ induces a
bijection between Kreweras intervals and stack triangulations which are known
to be in bijection with ternary trees.


title: Absorption spectroscopy of individual single-walled carbon nanotubes

abstract:
  Current methods for producing single-walled carbon nanotubes (SWNTs) lead to
heterogeneous samples containing mixtures of metallic and semiconducting
species with a variety of lengths and defects. Optical detection at the single
nanotube level should thus offer the possibility to examine these
heterogeneities provided that both SWNT species are equally well detected.
Here, we used photothermal heterodyne detection to record absorption images and
spectra of individual SWNTs. Because this photothermal method relies only on
light absorption, it readily detects metallic nanotubes as well as the emissive
semiconducting species. The first and second optical transitions in individual
semicontucting nanotubes have been probed. Comparison between the emission and
absorption spectra of the lowest-lying optical transition reveal mainly small
Stokes shifts. Side bands in the near-infrared absorption spectra are observed
and assigned to exciton-phonon bound states. No such sidebands are detected
around the lowest transition of metallic nanotubes.


title: Torsion units in integral group ring of the Mathieu simple group M22

abstract:
  We investigate the possible character values of torsion units of the
normalized unit group of the integral group ring of Mathieu sporadic group
$M_{22}$. We confirm the Kimmerle conjecture on prime graphs for this group and
specify the partial augmentations for possible counterexamples to the stronger
Zassenhaus conjecture.


title:
Methanofullerene Elongated Nanostructure Formation for Enhanced Organic
  Solar Cells

abstract:
  Using transmission electron microscopy (TEM) and Z-contrast imaging we have
demonstrated elongated nanostructure formation of fullerene derivative
[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) within an organic host
through annealing. The annealing provides an enhanced mobility of the PCBM
molecules and, with good initial dispersion, allows for the formation of
exaggerated grain growth within the polymer host. We have assembled these
nanostructures within the regioregular conjugated polymer
poly(3-hexylthiophene) (P3HT). This PCBM elongated nanostructure formation
maybe responsible for the very high efficiencies observed, at very low loadings
of PCBM (1:0.6, polymer to PCBM), in annealed photovoltaics. Moreover, our high
resolution TEM and electron energy loss spectroscopy studies clearly show that
the PCBM crystals remain crystalline and are unaffected by the 200-keV electron
beam


title: Radiatively broken symmetries of nonhierarchical neutrinos

abstract:
  Symmetry-based ideas, such as the quark-lepton complementarity (QLC)
principle and the tri-bimaximal mixing (TBM) scheme, have been proposed to
explain the observed mixing pattern of neutrinos. We argue that such symmetry
relations need to be imposed at a high scale $\Lambda \sim 10^{12}$ GeV
characterizing the large masses of right-handed neutrinos required to implement
the seesaw mechanism. For nonhierarchical neutrinos, renormalisation group
evolution down to a laboratory energy scale $\lambda \sim 10^3$ GeV tends to
radiatively break these symmetries at a significant level and spoil the mixing
pattern predicted by them. However, for Majorana neutrinos, suitable
constraints on the extra phases $\alpha_{2,3}$ enable the retention of those
high scale mixing patterns at laboratory energies. We examine this issue within
the Minimal Supersymmetric Standard Model (MSSM) and demonstrate the fact
posited above for two versions of QLC and two versions of TBM. The appropriate
constraints are worked out for all these four cases. Specifically, a preference
for $\alpha_2 \approx \pi$ (i.e. $m_1 \approx -m_2$) emerges in each case. We
also show how a future accurate measurement of $\theta_{13}$ may enable some
discrimination among these four cases in spite of renormalization group
evolution.


title: Alignment and signed-intensity anomalies in WMAP data

abstract:
  Significant alignment and signed-intensity anomalies of local features of the
cosmic microwave background (CMB) are detected on the three-year WMAP data,
through a decomposition of the signal with steerable wavelets on the sphere.
Firstly, an alignment analysis identifies two mean preferred planes in the sky,
both with normal axes close to the CMB dipole axis. The first plane is defined
by the directions toward which local CMB features are anomalously aligned. A
mean preferred axis is also identified in this plane, located very close to the
ecliptic poles axis. The second plane is defined by the directions anomalously
avoided by local CMB features. This alignment anomaly provides further insight
on recent results (Wiaux et al. 2006). Secondly, a signed-intensity analysis
identifies three mean preferred directions in the southern galactic hemisphere
with anomalously high or low temperature of local CMB features: a cold spot
essentially identified with a known cold spot (Vielva et al. 2004), a second
cold spot lying very close to the southern end of the CMB dipole axis, and a
hot spot lying close to the southern end of the ecliptic poles axis. In both
analyses, the anomalies are observed at wavelet scales corresponding to angular
sizes around 10 degress on the celestial sphere, with global significance
levels around 1%. Further investigation reveals that the alignment and
signed-intensity anomalies are only very partially related. Instrumental noise,
foreground emissions, as well as some form of other systematics, are strongly
rejected as possible origins of the detections. An explanation might still be
envisaged in terms of a global violation of the isotropy of the Universe,
inducing an intrinsic statistical anisotropy of the CMB.


title: Contractible Lie groups over local fields

abstract:
  Let G be a Lie group over a local field of positive characteristic which
admits a contractive automorphism f (i.e., the forward iterates f^n(x) of each
group element x converge to the neutral element 1). We show that then G is a
torsion group of finite exponent and nilpotent. We also obtain results
concerning the interplay between contractive automorphisms of Lie groups over
local fields, contractive automorphisms of their Lie algebras, and positive
gradations thereon. Some of the results even extend to Lie groups over
arbitrary complete ultrametric fields.


title:
The square gradient model in a two-phase mixture I. \\Equilibrium
  properties

abstract:
  In order to describe a nonuniform equilibrium mixture with an interface
between two coexisting phases it is necessary to consider contributions to the
Helmholtz energy which depend on the gradients of for instance the density. Van
der Waals \cite{vdW/sg, vdW/translation} was the first to introduce such a
term, which is very important in the interfacial region for a one-component
system. Cahn & Hilliard \cite{cahnhilliard/fens/I} extended this analysis to a
binary mixture by introducing gradient terms of the mol fraction. We give an
systematic extension of the gradient theory to three-dimensional
multi-component systems.


title: Luminous Red Galaxy Clustering at z~0.7 - First Results using AAOmega

abstract:
  We report on the AAT-AAOmega LRG Pilot observing run to establish the
feasibility of a large spectroscopic survey using the new AAOmega instrument.
We have selected Luminous Red Galaxies (LRGs) using single epoch SDSS
riz-photometry to i<20.5 and z<20.2. We have observed in 3 fields including the
COSMOS field and the COMBO-17 S11 field, obtaining a sample of ~600 redshift
z>=0.5 LRGs. Exposure times varied from 1 - 4 hours to determine the minimum
exposure for AAOmega to make an essentially complete LRG redshift survey in
average conditions. We show that LRG redshifts to i<20.5 can measured in
approximately 1.5hr exposures and present comparisons with 2SLAQ and COMBO-17
(photo-)redshifts. Crucially, the riz selection coupled with the 3-4 times
improved AAOmega throughput is shown to extend the LRG mean redshift from
z=0.55 for 2SLAQ to z=0.681+/- 0.005 for riz-selected LRGs. This extended range
is vital for maximising the S/N for the detection of the baryon acoustic
oscillations (BAOs). Furthermore, we show that the amplitude of LRG clustering
is s_0 = 9.9+/-0.7 h^-1 Mpc, as high as that seen in the 2SLAQ LRG Survey.
Consistent results for the real-space amplitude are found from projected and
semi-projected correlation functions. This high clustering amplitude is
consistent with a long-lived population whose bias evolves as predicted by a
simple ``high-peaks'' model. We conclude that a redshift survey of 360 000 LRGs
over 3000deg^2, with an effective volume some 4 times bigger than previously
used to detect BAO with LRGs, is possible with AAOmega in 170 nights.


title: Notes on Superconformal Chern-Simons-Matter Theories

abstract:
  The three dimensional N=2 supersymmetric Chern-Simons theory coupled to
matter fields, possibly deformed by a superpotential, give rise to a large
class of exactly conformal theories with Lagrangian descriptions. These
theories can be arbitrarily weakly coupled, and hence can be studied
perturbatively. We study the theories in the large N limit, and compute the
two-loop anomalous dimension of certain long operators. Our result suggests
that various N=2 U(N) Chern-Simons theories coupled to suitable matter fields
are dual to open or closed string theories in AdS4, which are not yet
constructed.


title:
Mesoscopic order and the dimentionality of long-range resonance energy
  transfer in supramolecular semiconductors

abstract:
  We present time-resolved photoluminescence measurements on two series of
oligo-p-phenylenevinylene materials that self-assemble into supramolecular
nanostructures with thermotropic reversibility in dodecane. One set of
derivatives form chiral, helical stacks while the second set form less
organised, frustrated stacks. Here we study the effects of supramolecular
organisation on the resonance energy transfer rates. We measure these rates in
nanoassemblies formed with mixed blends of oligomers and compare them with the
rates predicted by Foerster theory. Our results and analysis show that control
of supramolecular order in the nanometre lengthscale has a dominant effect on
the efficiency and dimentionality of resonance energy transfer.


title: Entropy of Open Lattice Systems

abstract:
  We investigate the behavior of the Gibbs-Shannon entropy of the stationary
nonequilibrium measure describing a one-dimensional lattice gas, of L sites,
with symmetric exclusion dynamics and in contact with particle reservoirs at
different densities. In the hydrodynamic scaling limit, L to infinity, the
leading order (O(L)) behavior of this entropy has been shown by Bahadoran to be
that of a product measure corresponding to strict local equilibrium; we compute
the first correction, which is O(1). The computation uses a formal expansion of
the entropy in terms of truncated correlation functions; for this system the
k-th such correlation is shown to be O(L^{-k+1}). This entropy correction
depends only on the scaled truncated pair correlation, which describes the
covariance of the density field. It coincides, in the large L limit, with the
corresponding correction obtained from a Gaussian measure with the same
covariance.


title:
The Suzaku Observation of the Nucleus of the Radio-Loud Active Galaxy
  Centaurus A: Constraints on Abundances of the Accreting Material

abstract:
  A Suzaku observation of the nucleus of the radio-loud AGN Centaurus A in 2005
has yielded a broadband spectrum spanning 0.3 to 250 keV. The net exposure
times after screening were: 70 ks per X-ray Imaging Spectrometer (XIS) camera,
60.8 ks for the Hard X-ray Detector (HXD) PIN, and 17.1 ks for the HXD-GSO. The
hard X-rays are fit by two power-laws of the same slope, absorbed by columns of
1.5 and 7 * 10^{23} cm^{-2} respectively. The spectrum is consistent with
previous suggestions that the power-law components are X-ray emission from the
sub-pc VLBI jet and from Bondi accretion at the core, but it is also consistent
with a partial covering interpretation. The soft band is dominated by thermal
emission from the diffuse plasma and is fit well by a two-temperature VAPEC
model, plus a third power-law component to account for scattered nuclear
emission, jet emission, and emission from X-ray Binaries and other point
sources. Narrow fluorescent emission lines from Fe, Si, S, Ar, Ca and Ni are
detected. The Fe K alpha line width yields a 200 light-day lower limit on the
distance from the black hole to the line-emitting gas. Fe, Ca, and S K-shell
absorption edges are detected. Elemental abundances are constrained via
absorption edge depths and strengths of the fluorescent and diffuse plasma
emission lines. The high metallicity ([Fe/H]=+0.1) of the circumnuclear
material suggests that it could not have originated in the relatively
metal-poor outer halo unless enrichment by local star formation has occurred.
Relative abundances are consistent with enrichment from Type II and Ia
supernovae.


title: The General Form Of Cyclic Orthonormal Generators In R^N

abstract:
  In this paper we give a definition of cyclic orthonormal generators (cogs) in
R^N. We give a general canonical form for their expression. Further, we give an
explicit formula for computing the canonical form of any given cog.


title: MR Imaging of Reynolds Dilatancy in the Bulk of Smooth Granular Flows

abstract:
  Dense granular matter has to expand in order to flow, a phenomenon known as
dilatancy. Here we perform, by means of Magnetic Resonance Imaging, direct
measurements of the evolution of the local packing density of a slow and smooth
granular shear flow generated in a split-bottomed geometry. The dilatancy is
found to be surprisingly strong. The dilated zone follow the region of large
strain rate and slowly spreads as a function of time. This suggests that the
local packing density is governed by the total amount of local strain
experienced since the start of the experiment.


title:
Distributed Algorithms for Spectrum Allocation, Power Control, Routing,
  and Congestion Control in Wireless Networks

abstract:
  We develop distributed algorithms to allocate resources in multi-hop wireless
networks with the aim of minimizing total cost. In order to observe the
fundamental duplexing constraint that co-located transmitters and receivers
cannot operate simultaneously on the same frequency band, we first devise a
spectrum allocation scheme that divides the whole spectrum into multiple
sub-bands and activates conflict-free links on each sub-band. We show that the
minimum number of required sub-bands grows asymptotically at a logarithmic rate
with the chromatic number of network connectivity graph. A simple distributed
and asynchronous algorithm is developed to feasibly activate links on the
available sub-bands. Given a feasible spectrum allocation, we then design
node-based distributed algorithms for optimally controlling the transmission
powers on active links for each sub-band, jointly with traffic routes and user
input rates in response to channel states and traffic demands. We show that
under specified conditions, the algorithms asymptotically converge to the
optimal operating point.


title: Lattice QCD thermodynamics with Wilson quarks

abstract:
  We review studies of QCD thermodynamics by lattice QCD simulations with
dynamical Wilson quarks. After explaining the basic properties of QCD with
Wilson quarks at finite temperature including the phase structure and the
scaling properties around the chiral phase transition, we discuss the critical
temperature, the equation of state and heavy-quark free energies.


title: Clustering Coefficients of Protein-Protein Interaction Networks

abstract:
  The properties of certain networks are determined by hidden variables that
are not explicitly measured. The conditional probability (propagator) that a
vertex with a given value of the hidden variable is connected to k of other
vertices determines all measurable properties. We study hidden variable models
and find an averaging approximation that enables us to obtain a general
analytical result for the propagator. Analytic results showing the validity of
the approximation are obtained. We apply hidden variable models to
protein-protein interaction networks (PINs) in which the hidden variable is the
association free-energy, determined by distributions that depend on
biochemistry and evolution. We compute degree distributions as well as
clustering coefficients of several PINs of different species; good agreement
with measured data is obtained. For the human interactome two different
parameter sets give the same degree distributions, but the computed clustering
coefficients differ by a factor of about two. This shows that degree
distributions are not sufficient to determine the properties of PINs.

categories: q-bio.QM cond-mat.stat-mech physics.bio-ph q-bio.MN


title: Kazhdan and Haagerup properties from the median viewpoint

abstract:
  We prove the existence of a close connection between spaces with measured
walls and median metric spaces. We then relate properties (T) and Haagerup
(a-T-menability) to actions on median spaces and on spaces with measured walls.
This allows us to explore the relationship between the classical properties (T)
and Haagerup and their versions using affine isometric actions on $L^p$-spaces.
It also allows us to answer an open problem on a dynamical characterization of
property (T), generalizing results of Robertson-Steger.


title: Thermal Effects of Rotation in Random Classical Zero-Point Radiation

abstract:
  The rotating reference system, two-point correlation functions, and energy
density are used as the basis for investigating thermal effects observed by a
detector rotating through random classical zero-point radiation. The RS
consists of Frenet -Serret orthogonal tetrads where the rotating detector is at
rest and has a constant acceleration vector. The CFs and the energy density at
the rotating reference system should be periodic with rotation period because
CF and energy density measurements is one of the tools the detector can use to
justify the periodicity of its motion. The CFs have been calculated for both
electromagnetic and massless scalar fields in two cases, with and without
taking this periodicity into consideration. It turned out that only periodic
CFs have some thermal features and particularly the Planck's factor with the
temperature T= h w /k . Regarding to the energy density of both electromagnetic
and massless scalar field it is shown that the detector rotating in the
zero-point radiation observes not only this original zero-point radiation but,
above that, also the radiation which would have been observed by an inertial
detector in the thermal bath with the Plank's spectrum at the temperature T.
This effect is masked by factor 2/3(4 gamma^2-1) for the electromagnetic field
and 2/9 (4 gamma ^2-1) for the massless scalar field, where the Lorentz factor
gamma=(1 - v^2 / c^2)^(1/2). Appearance of these masking factors is connected
with the fact that rotation is defined by two parameters, angular velocity w
and the radius of rotation, in contrast with a uniformly accelerated linear
motion which is defined by only one parameter, acceleration a. Our calculations
involve classical point of view only and to the best of our knowledge these
results have not been reported in quantum theory yet.


title: Theory of magnetic deflagration

abstract:
  Theory of magnetic deflagration (avalanches) in crystals of molecular magnets
has been developed. The phenomenon resembles the burning of a chemical
substance, with the Zeeman energy playing the role of the chemical energy.
Non-destructive reversible character of magnetic deflagration, as well as the
possibility to continuously tune the flammability of the crystal by changing
the magnetic field, makes molecular magnets an attractive toy system for a
detailed study of the burning process. Besides simplicity, new features, as
compared to the chemical burning, include possibility of quantum decay of
metastable spin states and strong temperature dependence of the heat capacity
and thermal conductivity. We obtain analytical and numerical solutions for
criteria of the ignition of magnetic deflagration, and compute the ignition
rate and the speed of the developed deflagration front.


title: Generalizing the notion of Koszul algebra

abstract:
  We introduce a generalization of the notion of a Koszul algebra, which
includes graded algebras with relations in different degrees, and we establish
some of the basic properties of these algebras. This class is closed under
twists, twisted tensor products, regular central extensions and Ore extensions.
We explore the monomial algebras in this class and we include some well-known
examples of algebras that fall into this class.


title: Investigation of a new conformation of double stranded DNA

abstract:
  It had been proposed that overstretching double stranded DNA from the 5-5
ends will produce a new fiber form of dsDNA that is narrower than the S form
that has been suggested to result when the dsDNA is overstretched from the 3-3
ends. We present the first comparison of the structures that result when dsDNA
is overstretched from the 5-5, 3-3, and 3-5 ends and show that the stability of
the overstretched form depends on the ends to which the force is applied. The
stability also depends strongly on the ionic environment as well as the
presence of reagents that bind to ssDNA.


title:
A large-scale correlated study of linear optical absorption and
  low-lying excited states of polyacenes: Pariser-Parr-Pople Hamiltonian

abstract:
  In this paper we present large-scale correlated calculations of linear
optical absorption spectrum of oligo-acenes containing up to seven benzene
rings. For the calculations we used the Pariser-Parr-Pople (P-P-P) Hamiltonian,
along with the configuration interaction (CI) technique at various levels such
as the full CI (FCI), the quadruple CI (QCI) and multi-reference
singles-doubles CI (MRSDCI). The role of Coulomb parameters used in the P-P-P
Hamiltonian was examined by considering standard Ohno parameters, as well as a
screened set of parameters. A detailed analysis of the many-body character of
the important excited states contributing to the linear absorption has also
been performed. The results of our calculations have been compared extensively
with the theoretical work of other authors, as well as with the experiments.


title: Helical, Angular and Radial Ordering in Narrow Capillaries

abstract:
  To enlighten the nature of the order-disorder and order-order transitions in
block copolymer melts confined in narrow capillaries we analyze peculiarities
of the conventional Landau weak crystallization theory of systems confined to
cylindrical geometry. This phenomenological approach provides a quantitative
classification of the cylindrical ordered morphologies by expansion of the
order parameter spatial distribution into the eigenfunctions of the Laplace
operator. The symmetry of the resulting ordered morphologies is shown to
strongly depend both on the boundary conditions (wall preference) and the ratio
of the cylinder radius and the wave length of the critical order parameter
fluctuations, which determine the bulk ordering of the system under
consideration. In particular, occurrence of the helical morphologies is a
rather general consequence of the imposed cylindrical symmetry for narrow
enough capillaries. We discuss also the ODT and OOT involving some other
simplest morphologies. The presented results are relevant also to other
ordering systems as charge-density waves appearing under addition of an ionic
solute to a solvent in its critical region, weakly charged polyelectrolyte
solutions in poor solvent, microemulsions etc.


title: Skew critical problems

abstract:
  Skew critical problems occur in continuous and discrete nonholonomic
Lagrangian systems. They are analogues of constrained optimization problems,
where the objective is differentiated in directions given by an apriori
distribution, instead of tangent directions to the constraint. We show
semiglobal existence and uniqueness for nondegenerate skew critical problems,
and show that the solutions of two skew critical problems have the same contact
as the problems themselves. Also, we develop some infrastructure that is
necessary to compute with contact order geometrically, directly on manifolds.


title:
Consistency between renormalization group running of chiral operator and
  counting rule -- Case of chiral pion production operator --

abstract:
  In nuclear chiral perturbation theory (ChPT), an operator is defined in a
space with a cutoff which may be varied within a certain range. The operator
runs as a result of the variation of the cutoff [renormalization group (RG)
running]. In order for ChPT to be useful, the operator should run in a way
consistent with the counting rule; that is, the running of chiral counter terms
have to be of natural size. We vary the cutoff using the Wilsonian
renormalization group (WRG) equation, and examine this consistency. As an
example, we study the s-wave pion production operator for NN\to d pi, derived
in ChPT. We demonstrate that the WRG running does not generate any
chiral-symmetry-violating (CSV) interaction, provided that we start with an
operator which does not contain a CSV term. We analytically show how the
counter terms are generated in the WRG running in case of the infinitesimal
cutoff reduction. Based on the analytic result, we argue a range of the cutoff
variation for which the running of the counter terms is of natural size. Then,
we numerically confirm this.


title:
Large Deviations for Partition Functions of Directed Polymers and Some
  Other Models in an IID Field

abstract:
  Consider the partition function of a directed polymer in an IID field. We
assume that both tails of the negative and the positive part of the field are
at least as light as exponential. It is a well-known fact that the free energy
of the polymer is equal to a deterministic constant for almost every
realization of the field and that the upper tail of the large deviations is
exponential. The lower tail of the large deviations is typically lighter than
exponential. In this paper we provide a method to obtain estimates on the rate
of decay of the lower tail of the large deviations, which are sharp up to
multiplicative constants. As a consequence, we show that the lower tail of the
large deviations exhibits three regimes, determined according to the tail of
the negative part of the field. Our method is simple to apply and can be used
to cover other oriented and non-oriented models including first/last-passage
percolation and the parabolic Anderson model