title:
Casimir invariants and the Jacobi identity in Dirac's theory of
  constrained Hamiltonian systems

abstract:
  We consider constrained Hamiltonian systems in the framework of Dirac's
theory. We show that the Jacobi identity results from imposing that the
constraints are Casimir invariants, regardless of the fact that the matrix of
Poisson brackets between constraints is invertible or not. We point out that
the proof we provide ensures the validity of the Jacobi identity everywhere in
phase space, and not just on the surface defined by the constraints. Two
examples are considered: A finite dimensional system with an odd number of
constraints, and the Vlasov-Poisson reduction from Vlasov-Maxwell equations.

categories: math-ph math.MP nlin.CD physics.plasm-ph


title:
Effective potential energy in St\ormer's problem for an inclined
  rotating magnetic dipole

abstract:
  We discuss the dynamics of a charged nonrelativistic particle in
electromagnetic field of a rotating magnetized celestial body. The equations of
motion of the particle are obtained and some particular solutions are found.
Effective potential energy is defined on the base of the first constant of
motion. Regions accessible and inaccessible for a charged particle motion are
studied and depicted for different values of a constant of motion.


title:
Hyperscaling violation in the 2D 8-state Potts model with long-range
  correlated disorder

abstract:
  The first-order phase transition of the two-dimensional eight-state Potts
model is shown to be rounded when long-range correlated disorder is coupled to
energy density. Critical exponents are estimated by means of large-scale Monte
Carlo simulations. In contrast to uncorrelated disorder, a violation of the
hyperscaling relation $\gamma/\nu=d-2x_\sigma$ is observed. Even though the
system is not frustrated, disorder fluctuations are strong enough to cause this
violation in the very same way as in the 3D random-field Ising model. In the
thermal sector too, evidence is given for such violation in the two
hyperscaling relations $\alpha/\nu=d-2x_\varepsilon$ and
$1/\nu=d-x_\varepsilon$. In contrast to the random field Ising model, at least
two hyperscaling violation exponents are needed. The scaling dimension of
energy is conjectured to be $x_\varepsilon=a/2$, where $a$ is the exponent of
the algebraic decay of disorder correlations.


title: Boson peak in overdoped manganites La_{1-x}Ca_{x}MnO_{3}

abstract:
  In the charge-ordered phase of strongly doped manganites
La$_{1-x}$Ca$_x$MnO$_3$ ($x \geq 0.5$) absorption lines appear in the terahertz
spectral range for commensurate $x$ values right below the charge-ordering
temperature. They are connected to acoustic phonons that become optically
active by folding of the Brillouin zone. At lower temperatures a strongly
asymmetric extra absorption band develops at frequencies corresponding to the
position of the lowest-energy van Hove singularity in the reduced Brillouin
zone. The band is assigned to the boson peak, i.e. to the excess of lattice
vibrational states over the standard Debye contribution. The folded phonons and
the boson peak do not show up for incommensurate calcium contents when no
distinct Brillouin zone folding exists.


title:
Optimization viewpoint on Kalman smoothing, with applications to robust
  and sparse estimation

abstract:
  In this paper, we present the optimization formulation of the Kalman
filtering and smoothing problems, and use this perspective to develop a variety
of extensions and applications. We first formulate classic Kalman smoothing as
a least squares problem, highlight special structure, and show that the classic
filtering and smoothing algorithms are equivalent to a particular algorithm for
solving this problem. Once this equivalence is established, we present
extensions of Kalman smoothing to systems with nonlinear process and
measurement models, systems with linear and nonlinear inequality constraints,
systems with outliers in the measurements or sudden changes in the state, and
systems where the sparsity of the state sequence must be accounted for. All
extensions preserve the computational efficiency of the classic algorithms, and
most of the extensions are illustrated with numerical examples, which are part
of an open source Kalman smoothing Matlab/Octave package.


title: Automatic Equivalence Proofs for Non-deterministic Coalgebras

abstract:
  A notion of generalized regular expressions for a large class of systems
modeled as coalgebras, and an analogue of Kleene's theorem and Kleene algebra,
were recently proposed by a subset of the authors of this paper. Examples of
the systems covered include infinite streams, deterministic automata, Mealy
machines and labelled transition systems. In this paper, we present a novel
algorithm to decide whether two expressions are bisimilar or not. The procedure
is implemented in the automatic theorem prover CIRC, by reducing coinduction to
an entailment relation between an algebraic specification and an appropriate
set of equations. We illustrate the generality of the tool with three examples:
infinite streams of real numbers, Mealy machines and labelled transition
systems.


title: Large D gravity and low D strings

abstract:
  We point out that in the limit of large number of dimensions a wide class of
non-extremal neutral black holes has a universal near horizon limit. The
limiting geometry is the two-dimensional black hole of string theory with a
two-dimensional target space. Its conformal symmetry explains properties of
massless scalars found recently in the large D limit. In analogy to the
situation for NS fivebranes, the dynamics near the horizon does not decouple
from the asymptotically flat region. We generalize the discussion to charged
black p-branes. For black branes with string charges, the near horizon geometry
is that of the three-dimensional black strings of Horne and Horowitz. The
analogies between the alpha' expansion in string theory and the large D
expansion in gravity suggest a possible effective string description of the
large D limit of black holes. We comment on applications to several subjects,
in particular to the problem of critical collapse.


title:
Robust error estimates for stabilized finite element approximations of
  the two dimensional Navier-Stokes equations with application to implicit
  large eddy simulation

abstract:
  We consider error estimates in weak parametrised norms for stabilized finite
element approximations of the two-dimensional Navier-Stokes' equations. These
weak norms can be related to the norms of certain filtered quantities, where
the parameter of the norm, relates to the filter width. Under the assumption of
the existence of a certain decomposition of the solution, into large eddies and
fine scale fluctuations, the constants of the estimates are proven to be
independent of both the Reynolds number and the Sobolev norm of the exact
solution. Instead they exhibit exponential growth with a coefficient
proportional to the maximum gradient of the large eddies. The error estimates
are on a posteriori form, but using Sobolev injections valid on finite element
spaces and the properties of the stabilization operators the residuals may be
upper bounded uniformly, leading to robust a priori error estimates.


title: Central compact objects in magnetic lethargy

abstract:
  Central Compact Objects are peculiar young neutron stars, with very low
external magnetic fields combined with high fluxes in the X-ray band and
surface temperature anisotropies. However, in their crust the magnetic field
can be strong, result of its burial during a short post-supernova hypercritical
accretion episode. The implications of this latter scenario for the temperature
anisotropy, pulsed fraction and luminosity are discussed.


title: Selecting polynomials for the Function Field Sieve

abstract:
  The Function Field Sieve algorithm is dedicated to computing discrete
logarithms in a finite field GF(q^n), where q is small an prime power. The
scope of this article is to select good polynomials for this algorithm by
defining and measuring the size property and the so-called root and
cancellation properties. In particular we present an algorithm for rapidly
testing a large set of polynomials. Our study also explains the behaviour of
inseparable polynomials, in particular we give an easy way to see that the
algorithm encompass the Coppersmith algorithm as a particular case.


title:
Purification-based metric to measure the distance between quantum states
  and processes

abstract:
  In this work we study the properties of an purification-based entropic metric
for measuring the distance between both quantum states and quantum processes.
This metric is defined as the square root of the entropy of the average of two
purifications of mixed quantum states which maximize the overlap between the
purified states. We analyze this metric and show that it satisfies many
appealing properties, which suggest this metric is an interesting proposal for
theoretical and experimental applications of quantum information.


title: A non FLC regular pentagonal tiling of the plane

abstract:
  In this paper we describe the pentagonal tiling of the plane defined in the
article "A regular pentagonal tiling of the plane" by P. L. Bowers and K.
Stephenson as a conformal substitution tiling and summarize many of its
properties given in the mentioned article. We show furthermore why such tiling
is not FLC with respect to the set of conformal isomorphisms.


title:
Representations of quantum groups at roots of unity, Whittaker vectors
  and q-W algebras

abstract:
  Let $U_\varepsilon({\mathfrak g})$ be the standard simply connected version
of the Drinfeld-Jumbo quantum group at an odd primitive m-th root of unity
$\varepsilon$. The center of $U_\varepsilon({\mathfrak g})$ contains a huge
commutative subalgebra isomorphic to the algebra $Z_G$ of regular functions on
(a finite covering of a big cell in) a complex connected, simply connected
algebraic group $G$ with Lie algebra $\mathfrak g$. Let $V$ be a
finite-dimensional representation of $U_\varepsilon({\mathfrak g})$ on which
$Z_G$ acts according to a non-trivial character $\eta_g$ given by evaluation of
regular functions at $g\in G$. Then $V$ is a representation of the
finite-dimensional algebra $U_{\eta_g}=U_\varepsilon({\mathfrak
g})/U_\varepsilon({\mathfrak g}){\rm Ker}~\eta_g$. We show that in this case,
under certain restrictions on $m$, $U_{\eta_g}$ contains a subalgebra
$U_{\eta_g}({\mathfrak m}_-)$ of dimension $m^{{\frac{1}{2}}{\rm
dim}~\mathcal{O}}$, where $\mathcal{O}$ is the conjugacy class of $g$, and
$U_{\eta_g}({\mathfrak m}_-)$ has a one-dimensional representation
$\mathbb{C}_{\chi_g}$. We also prove that if $V$ is not trivial then the space
of Whittaker vectors ${\rm Hom}_{U_{\eta_g}({\mathfrak
m}_-)}(\mathbb{C}_{\chi_g},V)$ is not trivial and the algebra $W_{\eta_g}={\rm
End}_{U_{\eta_g}}(U_{\eta_g}\otimes_{U_{\eta_g}({\mathfrak
m}_-)}\mathbb{C}_{\chi_g})$ naturally acts on it which gives rise to a
Schur-type duality between representations of the algebra $U_{\eta_g}$ and of
the algebra $W_{\eta_g}$ called a q-W algebra.


title: Half - Quantum Vortices

abstract:
  Unlike to superfluid $^4$He the superfluid $^3$He-A support the existence of
vortices with half quantum of circulation as well as single quantum vortices.
The singular single quanta vortices as well as nonsingular vortices with 2
quanta of circulation have been revealed in rotating $^3$He-A. However, the
half quantum vortices in open geometry always possess an extra energy due to
spin-orbit coupling leading to formation of domain wall at distances larger
than dipole length $\sim 10^{-3}cm$ from the vortex axis.
  Fortunately the same magnetic dipole-dipole interaction does not prevent the
existence of half-quantum vortices in the polar phase of superfluid $^3$He
recently discovered in peculiar porous media "nematically ordered" aerogel.
Here we discuss this exotic possibility.
  The discoveries of half-quantum vortices in triplet pairing superconductor
Sr$_2$RuO$_4$ as well in the exciton-polariton condensates are the other parts
of the story about half-quantum vortices also described in the paper.


title: Weak morphisms of higher dimensional automata

abstract:
  We introduce weak morphisms of higher dimensional automata and use them to
define preorder relations for HDAs, among which homeomorphic abstraction and
trace equivalent abstraction. It is shown that homeomorphic abstraction is
essentially always stronger than trace equivalent abstraction. We also define
the trace language of an HDA and show that, for a large class of HDAs, it is
invariant under trace equivalent abstraction.


title:
Quasi continuous-time impurity solver for the dynamical mean-field
  theory with linear scaling in the inverse temperature

abstract:
  We present an algorithm for solving the self-consistency equations of the
dynamical mean-field theory (DMFT) with high precision and efficiency at low
temperatures. In each DMFT iteration, the impurity problem is mapped to an
auxiliary Hamiltonian, for which the Green function is computed by combining
determinantal quantum Monte Carlo (BSS-QMC) calculations with a multigrid
extrapolation procedure. The method is numerically exact, i.e., yields results
which are free of significant Trotter errors, but retains the BSS advantage,
compared to direct QMC impurity solvers, of linear (instead of cubic) scaling
with the inverse temperature. The new algorithm is applied to the half-filled
Hubbard model close to the Mott transition; detailed comparisons with exact
diagonalization, Hirsch-Fye QMC, and continuous-time QMC are provided.


title:
The balancing act of template bank construction: inspiral waveform
  template banks for gravitational-wave detectors and optimizations at fixed
  computational cost

abstract:
  Gravitational-wave searches for signals from inspiralling compact binaries
have relied on matched filtering banks of waveforms (called template banks) to
try to extract the signal waveforms from the detector data. These template
banks have been constructed using four main considerations, the region of
parameter space of interest, the sensitivity of the detector, the matched
filtering bandwidth, and the sensitivity one is willing to lose due to the
granularity of template placement, the latter of which is governed by the
minimal match. In this work we describe how the choice of the lower frequency
cutoff, the lower end of the matched filter frequency band, can be optimized
for detection. We also show how the minimal match can be optimally chosen in
the case of limited computational resources. These techniques are applied to
searches for binary neutron star signals that have been previously performed
when analyzing Initial LIGO and Virgo data and will be performed analyzing
Advanced LIGO and Advanced Virgo data using the expected detector sensitivity.
By following the algorithms put forward here, the volume sensitivity of these
searches is predicted to improve without increasing the computational cost of
performing the search.


title: Quantifying stretching and rearrangement in epithelial sheet migration

abstract:
  Although understanding the collective migration of cells, such as that seen
in epithelial sheets, is essential for understanding diseases such as
metastatic cancer, this motion is not yet as well characterized as individual
cell migration. Here we adapt quantitative metrics used to characterize the
flow and deformation of soft matter to contrast different types of motion
within a migrating sheet of cells. Using a Finite-Time Lyapunov Exponent (FTLE)
analysis, we find that - in spite of large fluctuations - the flow field of an
epithelial cell sheet is not chaotic. Stretching of a sheet of cells (i.e.,
positive FTLE) is localized at the leading edge of migration. By decomposing
the motion of the cells into affine and non-affine components using the metric
D$^{2}_{min}$, we quantify local plastic rearrangements and describe the motion
of a group of cells in a novel way. We find an increase in plastic
rearrangements with increasing cell densities, whereas inanimate systems tend
to exhibit less non-affine rearrangements with increasing density.


title:
Long-term periodicity in LSI+61303 as beat frequency between orbital and
  precessional rate

abstract:
  Context: In the binary system LSI+61303 the peak flux density of the radio
outburst, which is related to the orbital period of 26.4960 +/- 0.0028d,
exibits a modulation of 1667 +/- 8 d. The radio emission at high spatial
resolution appears structured in a precessing jet with a precessional period of
27-28 d. Aims: How close is the precessional period of the radio jet to the
orbital period? Any periodicity in the radio emission should be revealed by
timing analysis. The aim of this work is to establish the accurate value of the
precessional period. Methods: We analyzed 6.7 years of the Green Bank
Interferometer database at 2.2 GHz and 8.3 GHz with the Lomb-Scargle and phase
dispersion minimization (PDM) methods and performed simulations. Results: The
periodograms show two periodicities, P1 = 26.49 +/- 0.07 d (\nu1=0.03775
d^{-1}) and P2 = 26.92 +/- 0.07 d (\nu2 = 0.03715 d^{-1}). Whereas radio
outbursts have been known to have nearly orbital occurrence P1 with timing
residuals exhibiting a puzzling sawtooth pattern, we probe in this paper that
they are actually periodical outbursts and that their period is Paverage=
(2/(\nu1 + \nu2)= 26.70 +/- 0.05 d. The period Paverage as well as the
long-term modulation Pbeat=1/(\nu1 - \nu2)=1667 +/- 393 d result from the beat
of the two close periods, the orbital P1 and the precessional P2 periods.
Conclusions: The precessional period, indicated by the astrometry to be of
27--28 d, is P2=26.92 d. The system \lsi seems to be one more case in astronomy
of beat, i.e., a phenomenon occurring when two physical processes create stable
variations of nearly equal frequencies. The very small difference in frequency
creates a long-term variation of period 1/(\nu1-\nu2). The long-term modulation
of 1667 d results from the beat of the two close orbital and precessional
rates.


title: Constraining Palatini cosmological models using GRB data

abstract:
  New constraints on previously investigated Palatini cosmological models
[arXiv:1109.3420] have been obtained by adding Gamma Ray Burst data
[arXiv:1205.2954].


title:
Photonuclear vector meson production in ultra-peripheral Pb-Pb
  collisions studied by the ALICE experiment at the LHC

abstract:
  The strong electromagnetic fields surrounding the Pb-ions accelerated at the
CERN Large Hadron Collider (LHC) allow two-photon and photonuclear interactions
to be studied in a so far unexplored kinematic regime. Exclusive
photoproduction of vector mesons can be studied in ultra-peripheral collisions,
where the impact parameters are larger than the sum of the nuclear radii and
hadronic interactions are strongly suppressed.
  During the heavy-ion runs at the LHC in 2010 and 2011, the ALICE
collaboration used special triggers to select ultra-peripheral collisions.
These triggers were based on the Muon spectrometer, the Time-of-Flight
detector, the Silicon Pixel detector, and the VZERO scintillator array.
Information from other detectors was also used in the analysis. The cross
section for coherent photoproduction of J/Psi mesons at forward rapidities will
be presented. The result will be compared to model calculations and its
implications for nuclear gluon shadowing will be discussed.


title:
Heat capacity jump at Tc and pressure derivatives of superconducting
  transition temperature in the Ba1-xKxFe2As2 (0.2 < x < 1.0) series

abstract:
  We present the evolution of the initial (up to ~ 10 kbar) hydrostatic,
pressure dependencies of Tc and of the ambient pressure jump in the heat
capacity associated with the superconducting transition as a function of K -
doping in the Ba1-xKxFe2As2 family of iron-based superconductors. The pressure
derivatives show weak but distinct anomaly near x ~ 0.7. In the same
concentration region Delta Cp at Tc deviates from the Delta Cp ~ T^3 scaling
found for most BaFe2As2 - based superconductors. These results are consistent
with a Lifshitz transition, and possible significant modification of the
superconducting state, occurring near x ~ 0.7.


title:
Neutral gas in Lyman-alpha emitting galaxies Haro 11 and ESO 338-IG04
  measured through sodium absorption

abstract:
  Context. The Lyman alpha emission line of galaxies is an important tool for
finding galaxies at high redshift, and thus probe the structure of the early
universe. However, the resonance nature of the line and its sensitivity to dust
and neutral gas is still not fully understood.
  Aims. We present measurements of the velocity, covering fraction and optical
depth of neutral gas in front of two well known local blue compact galaxies
that show Lyman alpha in emission: ESO 338-IG 04 and Haro 11. We thus test
observationally the hypothesis that Lyman alpha can escape through neutral gas
by being Doppler shifted out of resonance.
  Methods. We present integral field spectroscopy from the GIRAFFE/Argus
spectrograph at VLT/FLAMES in Paranal, Chile. The excellent wavelength
resolution allows us to accurately measure the velocity of the ionized and
neutral gas through the H-alpha emission and Na D absorption, which traces the
ionized medium and cold interstellar gas, respectively. We also present
independent measurements with the VLT/X-shooter spectrograph which confirm our
results.
  Results. For ESO 338-IG04, we measure no significant shift of neutral gas.
The best fit velocity is -15 (16) km/s. For Haro 11, we see an outflow from
knot B at 44 (13) km/s and infalling gas towards knot C with 32 (12) km/s.
Based on the relative strength of the Na D absorption lines, we estimate low
covering fractions of neutral gas (down to 10%) in all three cases.
  Conclusions. The Na D absorption likely occurs in dense clumps with higher
column densities than where the bulk of the Ly-alpha scattering takes place.
Still, we find no strong correlation between outflowing neutral gas and a high
Lyman alpha escape fraction. The Lyman alpha photons from these two galaxies
are therefore likely escaping due to a low column density and/or covering
fraction.


title:
Transition between localized and extended states in the hierarchical
  Anderson model

abstract:
  We present strong numerical evidence for the existence of a
localization-delocalization transition in the eigenstates of the 1-D Anderson
model with long-range hierarchical hopping. Hierarchical models are important
because of the well-known mapping between their phases and those of models with
short range hopping in higher dimensions, and also because the renormalization
group can be applied exactly without the approximations that generally are
required in other models. In the hierarchical Anderson model we find a finite
critical disorder strength Wc where the average inverse participation ratio
goes to zero; at small disorder W < Wc the model lies in a delocalized phase.
This result is based on numerical calculation of the inverse participation
ratio in the infinite volume limit using an exact renormalization group
approach facilitated by the model's hierarchical structure. Our results are
consistent with the presence of an Anderson transition in short-range models
with D > 2 dimensions, which was predicted using renormalization group
arguments. Our finding should stimulate interest in the hierarchical Anderson
model as a simplified and tractable model of the Anderson localization
transition which occurs in finite-dimensional systems with short-range hopping.


title: Computing as compression: the SP theory of intelligence

abstract:
  This paper provides an overview of the SP theory of intelligence and its
central idea that artificial intelligence, mainstream computing, and much of
human perception and cognition, may be understood as information compression.
  The background and origins of the SP theory are described, and the main
elements of the theory, including the key concept of multiple alignment,
borrowed from bioinformatics but with important differences. Associated with
the SP theory is the idea that redundancy in information may be understood as
repetition of patterns, that compression of information may be achieved via the
matching and unification (merging) of patterns, and that computing and
information compression are both fundamentally probabilistic. It appears that
the SP system is Turing-equivalent in the sense that anything that may be
computed with a Turing machine may, in principle, also be computed with an SP
machine.
  One of the main strengths of the SP theory and the multiple alignment concept
is in modelling concepts and phenomena in artificial intelligence. Within that
area, the SP theory provides a simple but versatile means of representing
different kinds of knowledge, it can model both the parsing and production of
natural language, with potential for the understanding and translation of
natural languages, it has strengths in pattern recognition, with potential in
computer vision, it can model several kinds of reasoning, and it has
capabilities in planning, problem solving, and unsupervised learning.
  The paper includes two examples showing how alternative parsings of an
ambiguous sentence may be modelled as multiple alignments, and another example
showing how the concept of multiple alignment may be applied in medical
diagnosis.


title: Fixed points and FLRW cosmologies: Flat case

abstract:
  We use phase space method to study possible consequences of fixed points in
flat FLRW models. One of these consequences is that a fluid with a finite sound
speed, or a differentiable pressure, reaches a fixed point in an infinite time
and has no finite-time singularities of types I, II and III described in
hep-th/0501025. It is impossible for such a fluid to cross the phantom divide
in a finite time. We show that a divergent $dp/dH$, or a speed of sound is
necessary but not sufficient condition for phantom crossing. We use pressure
properties, such as asymptotic behavior and fixed points, to qualitatively
describe the entire behavior of a solution in flat FLRW models. We discuss FLRW
models with bulk viscosity $\eta \sim \rho^r$, in particular, solutions for
$r=1$ and $r=1/4$ cases, which can be expressed in terms of Lambert-W function.
The last solution behaves either as a nonsingular phantom fluid or a unified
dark fluid. Using causality and stability constraints, we show that the
universe must end as a de Sitter space. Relaxing the stability constraint leads
to a de Sitter universe, an empty universe, or a turnaround solution that
reaches a maximum size, then recollapses.


title:
Search for a neutrino emission from the Fermi Bubbles with the ANTARES
  telescope

abstract:
  ANTARES is the largest neutrino telescope in the Northern hemisphere. The
main scientific goal is the search for cosmic neutrinos coming from galactic
and extragalactic sources. Neutrinos are detected through the Cherenkov light
emitted along the path of charged particles produced in neutrino interactions
inside or in the vicinity of the detector. ANTARES is sensitive to all flavors
though it is optimized for muon neutrinos. The detector has been taking data in
its complete configuration since May 2008.
  Using data collected in the period 2007-2010, the first analysis devoted to
the search for neutrinos from the Fermi Bubbles is presented. The Fermi Bubbles
are characterized by gamma emission with a E^{-2} spectrum and a relatively
constant intensity all over the space. According to a proposed hadronic
mechanism for this gamma-ray emission, the Fermi Bubbles can be a source of
high-energy neutrinos. No evidence of a neutrino signal is found in the ANTARES
data. Therefore upper limits are calculated for neutrino fluxes with different
energy cutoffs.


title:
Oxygen spectral line synthesis: 3D non-LTE with CO5BOLD hydrodynamical
  model atmospheres

abstract:
  In this work we present first results of our current project aimed at
combining the 3D hydrodynamical stellar atmosphere approach with non-LTE (NLTE)
spectral line synthesis for a number of key chemical species. We carried out a
full 3D-NLTE spectrum synthesis of the oxygen IR 777 nm triplet, using a
modified and improved version of our NLTE3D package to calculate departure
coefficients for the atomic levels of oxygen in a CO5BOLD 3D hydrodynamical
solar model atmosphere. Spectral line synthesis was subsequently performed with
the Linfor 3D code. In agreement with previous studies, we find that the lines
of the oxygen triplet produce deeper cores under NLTE conditions, due to the
diminished line source function in the line forming region. This means that the
solar oxygen IR 777 nm lines should be stronger in NLTE, leading to negative 3D
NLTE-LTE abundance corrections. Qualitatively this result would support
previous claims for a relatively low solar oxygen abundance. Finally, we
outline several further steps that need to be taken in order to improve the
physical realism and numerical accuracy of our current 3D-NLTE calculations.


title: Security Assessment of Software Design using Neural Network

abstract:
  Security flaws in software applications today has been attributed mostly to
design flaws. With limited budget and time to release software into the market,
many developers often consider security as an afterthought. Previous research
shows that integrating security into software applications at a later stage of
software development lifecycle (SDLC) has been found to be more costly than
when it is integrated during the early stages. To assist in the integration of
security early in the SDLC stages, a new approach for assessing security during
the design phase by neural network is investigated in this paper. Our findings
show that by training a back propagation neural network to identify attack
patterns, possible attacks can be identified from design scenarios presented to
it. The result of performance of the neural network is presented in this paper.


title: Multiwavelength Observations of Gamma-ray Binary Candidates

abstract:
  A rare group of high mass X-ray binaries (HMXBs) are known that also exhibit
MeV, GeV, and/or TeV emission ("gamma-ray binaries"). Expanding the sample of
gamma-ray binaries and identifying unknown Fermi sources are currently of great
interest to the community. Based upon their positional coincidence with the
unidentified Fermi sources 1FGL J1127.7-6244c and 1FGL J1808.5-1954c, the Be
stars HD 99771 and HD 165783 have been proposed as gamma-ray binary candidates.
During Fermi Cycle 4, we have performed multiwavelength observations of these
sources using XMM-Newton and the CTIO 1.5m telescope. We do not confirm high
energy emission from the Be stars. Here we examine other X-ray sources in the
field of view that are potential counterparts to the Fermi sources.


title: A problem around Mahler functions

abstract:
  Let $K$ be a field of characteristic zero and $k$ and $l$ be two
multiplicatively independent positive integers. We prove the following result
that was conjectured by Loxton and van der Poorten during the Eighties: a power
series $F(z)\in K[[z]]$ satisfies both a $k$- and a $l$-Mahler type functional
equation if and only if it is a rational function.


title:
Two-dimensional Bloch electrons in perpendicular magnetic fields: an
  exact calculation of the Hofstadter butterfly spectrum

abstract:
  The problem of two-dimensional, independent electrons subject to a periodic
potential and a uniform perpendicular magnetic field unveils surprisingly rich
physics, as epitomized by the fractal energy spectrum known as Hofstadter's
Butterfly. It has hitherto been addressed using various approximations rooted
in either the strong potential or the strong field limiting cases. Here we
report calculations of the full spectrum of the single-particle Schr\"{o}dinger
equation without further approximations. Our method is exact, up to numerical
precision, for any combination of potential and uniform field strength. We
first study a situation that corresponds to the strong potential limit, and
compare the exact results to the predictions of a Hofstadter-like model. We
then go on to analyze the evolution of the fractal spectrum from a Landau-like
nearly-free electron system to the Hofstadter tight-binding limit by tuning the
amplitude of the modulation potential.


title:
Evaluacion experimental del factor de estabilidad en nanoemulsiones
  dodecano/agua

abstract:
  The turbidity of four different oil/water (o/w) ionic nanoemulsions is
studied as a function of time. The emulsions are stabilized with sodium dodecyl
sulphate, and are composed of pure dodecane, and mixtures of dodecane, squalene
and tetrachloroethylene. For each system plots of the stability factor as a
function of the ionic strength of the solution are reported. The results allow
establishing the relative importance of buoyancy and Ostwald ripening on the
aggregation rates.


title:
The vertical structure of Jupiter's equatorial zonal wind above the
  cloud deck, derived using mesoscale gravity waves

abstract:
  Data from the Galileo Probe, collected during its descent into Jupiter's
atmosphere, is used to obtain a vertical profile of the zonal wind from
$\mathbf{\sim 0.5}$ bar (upper troposphere) to $\mathbf{\sim 0.1\, \mu{bar}}$
(lower thermosphere) at the probe entry site. This is accomplished by
constructing a map of gravity wave Lomb-Scargle periodograms as a function of
altitude. The profile obtained from the map indicates that the wind speed above
the visible cloud deck increases with height to $\mathbf{\sim 150}$
m\,s$\mathbf{^{-1}}$ and then levels off at this value over a broad altitude
range. The location of the turbopause, as a region of wide wave spectrum, is
also identified from the map. In addition, a cross-equatorial oscillation of a
jet, which has previously been linked to the quasi-quadrennial oscillation in
the stratosphere, is suggested by the profile.


title: The Faa di Bruno formula revisited

abstract:
  We present a new variant of the Faa di Bruno formula with a simpler summation
order.


title:
The ASTRI Project: prototype status and future plans for a Cherenkov
  dual-mirror small-telescope array

abstract:
  ASTRI ("Astrofisica con Specchi a Tecnologia Replicante Italiana") is a
flagship project of the Italian Ministry of Education, University and Research.
Within this framework, INAF is currently developing a wide field of view (9.6
degrees in diameter) end-to-end prototype of the CTA small-size telescope
(SST), devoted to the investigation of the energy range from a fraction of TeV
up to tens of TeVs, and scheduled to start data acquisition in 2014. For the
first time, a dual-mirror Schwarzschild-Couder optical design will be adopted
on a Cherenkov telescope, in order to obtain a compact optical configuration. A
second challenging, but innovative technical solution consists of a modular
focal surface camera based on Silicon photo-multipliers with a logical pixel
size of 6.2mm x 6.2mm. Here we describe the current status of the project, the
expected performance, and its possible evolution in terms of an SST mini-array.
This CTA-SST precursor, composed of a few SSTs and developed in collaboration
with CTA international partners, could not only peruse the technological
solutions adopted by ASTRI, but also address a few scientific test cases that
are discussed in detail.


title:
ABACUS: frequent pAttern mining-BAsed Community discovery in
  mUltidimensional networkS

abstract:
  Community Discovery in complex networks is the problem of detecting, for each
node of the network, its membership to one of more groups of nodes, the
communities, that are densely connected, or highly interactive, or, more in
general, similar, according to a similarity function. So far, the problem has
been widely studied in monodimensional networks, i.e. networks where only one
connection between two entities can exist. However, real networks are often
multidimensional, i.e., multiple connections between any two nodes can exist,
either reflecting different kinds of relationships, or representing different
values of the same type of tie. In this context, the problem of Community
Discovery has to be redefined, taking into account multidimensional structure
of the graph. We define a new concept of community that groups together nodes
sharing memberships to the same monodimensional communities in the different
single dimensions. As we show, such communities are meaningful and able to
group highly correlated nodes, even if they might not be connected in any of
the monodimensional networks. We devise ABACUS (Apriori-BAsed Community
discoverer in mUltidimensional networkS), an algorithm that is able to extract
multidimensional communities based on the apriori itemset miner applied to
monodimensional community memberships. Experiments on two different real
multidimensional networks confirm the meaningfulness of the introduced
concepts, and open the way for a new class of algorithms for community
discovery that do not rely on the dense connections among nodes.


title:
Lack of coupling between superconductivity and orthorhombic distortion
  in stoichiometric single-crystalline FeSe

abstract:
  The coupling between superconductivity and othorhombic distortion is studied
in vapor-grown FeSe single crystals using high-resolution thermal-expansion
measurements. In contrast to the Ba122-based (Ba122) superconductors, we find
that superconductivity does not reduce the orthorhombicity below Tc. Instead we
find that superconductivity couples strongly to the in-plane area, which
explains the large hydrostatic pressure effects. We discuss our results in
light of the spinnematic scenario and argue that FeSe has many features quite
different from the typical Fe-based superconductors.


title: Electron Spin Relaxation in Graphene Nanoribbon Quantum Dots

abstract:
  Graphene is promising as a host material for electron spin qubits because of
its predicted potential for long coherence times. In armchair graphene
nanoribbons (aGNRs) a small bandgap is opened, allowing for electrically gated
quantum dots, and furthermore the valley degeneracy is lifted. The spin
lifetime T_1 is limited by spin relaxation, where the Zeeman energy is absorbed
by lattice vibrations, mediated by spin-orbit and electron-phonon coupling. We
have calculated T_1 by treating all couplings analytically and find that T_1
can be in the range of seconds for several reasons: (i) low phonon density of
states away from Van Hove singularities; (ii) destructive interference between
two relaxation mechanisms; (iii) Van Vleck cancellation at low magnetic fields;
(iv) vanishing coupling to out-of-plane modes in lowest order due to the
electronic structure of aGNRs. Owing to the vanishing nuclear spin of 12C, T_1
may be a good measure for overall coherence. These results and recent advances
in the controlled production of graphene nanoribbons make this system
interesting for spintronics applications.


title:
Lyapunov spectrum of a relativistic stochastic flow in the Poincar\'e
  group

abstract:
  We determine the Lyapunov spectrum and stable manifolds of some stochastic
flows on the Poincar\'e group associated to Dudley's relativistic processes.


title: Knudsen layer formation in laser induced thermal desorption

abstract:
  Laser induced thermal desorption of Xe atoms into vacuum from a metal surface
following the nano-second pulsed laser heating was investigated by the
time-of-flight (TOF) measurement. The desorption flow was studied at a wide
range of desorption flux by varying the initially prepared Xe coverage {\Theta}
(1 ML = 4.5*10^18 atoms/m^2). At {\Theta} = 0.3 ML, the TOF of Xe was well
represented by a Maxwell-Boltzmann velocity distribution, which is in good
agreement with thermal desorption followed by collision-free flow. At {\Theta}
> 0.3 ML, the peak positions of the TOF spectra were shifted towards the
smaller values and became constant at large {\Theta}, which were well fitted
with a shifted Maxwell-Boltzmann velocity distribution with a temperature T_D
and a stream velocity u. With T_D fixed at 165 K, u was found to increase from
80 to 125 m/ s with increasing {\Theta} from 1.2 to 4 ML. At {\Theta} > 4 ML,
the value of u become constant at 125 m/ s. The converging feature of u was
found to be consistent with analytical predictions and simulated results based
on the Knudsen layer formation theory. We found that the Knudsen layer
formation in laser desorption is completed at Knudsen number Kn <0.39.


title:
Probing the role of polycyclic aromatic hydrocarbons in the
  photoelectric heating within photodissociation regions

abstract:
  We observationally investigate the relation between the photoelectric heating
efficiency in PDRs and the charge of PAHs, which are considered to play a key
role in photoelectric heating. Using PACS onboard Herschel, we observed six
PDRs spanning a wide range of FUV radiation fields (G_0=100-10^5). To measure
the photoelectric heating efficiency, we obtained the intensities of the main
cooling lines, i.e., the [OI]63um, 145um, and [CII]158um, as well as the FIR
continuum intensity. We used Spitzer/IRS spectroscopic mapping observations to
investigate the MIR PAH features in the same regions. We decomposed the MIR PAH
emission into that of neutral (PAH^0) and positively ionized (PAH^+) species to
derive the fraction of the positively charged PAHs, and compare it to the
photoelectric heating efficiency. The heating efficiency traced by
([OI]63um+[OI]145um+[CII]158um) / TIR, ranges between 0.1% and 0.9% in
different sources, and the fraction of PAH^+ relative to (PAH^0 + PAH^+) spans
from 0(+11)% to 87(+/-10)%. All positions with a high PAH^+ fraction show a low
heating efficiency, and all positions with a high heating efficiency have a low
PAH^+ fraction, supporting the scenario in which a positive grain charge
results in a decreased heating efficiency. Theoretical estimates of the
photoelectric heating efficiency show a stronger dependence on the charging
parameter gamma=G_0 T^{1/2}/n_e than the observed efficiency reported in this
study, and the discrepancy is significant at low gamma. The photoelectric
heating efficiency on PAHs, traced by ([OI]63um+[OI]145um+[CII]158um) /
(PAH+[OI]63um+[OI]145um+[CII]158um), shows a much better match between the
observations and the theoretical estimates. The good agreement of the
photoelectric heating efficiency on PAHs with a theoretical model indicates the
dominant contribution of PAHs to the photoelectric heating. (abridged for
arXiv)


title:
Helium at elevated pressures: Quantum liquid with non-static shear
  rigidity

abstract:
  The properties of liquid helium have always been a fascinating subject to
scientists. The phonon theory of liquids taking into account liquid non-static
shear rigidity is employed here for studying internal energy and heat capacity
of compressed liquid 4-He. We demonstrate good agreement of calculated and
experimental heat capacity of liquid helium at elevated pressures and
supercritical temperatures. Unexpectedly helium remains a quantum liquid at
elevated pressures for a wide range of temperature supporting both longitudinal
and transverse-like phonon excitations. We have found that in the very wide
pressure range 5 MPa-500 MPa liquid helium near melting temperature is both
solid-like and quantum.


title:
Tunable spontaneous emission from layered graphene/dielectric tunnel
  junctions

abstract:
  There has been a rapidly growing interest in optoelectronic properties of
graphene and associated structures. Despite the general belief on absence of
spontaneous emission in graphene, which is normally attributed to its unique
ultrafast carrier momentum relaxation mechanisms, there exist a few recent
evidences of strong optical gain and spontaneous light emission from mono-layer
graphene, supported by observations of dominant role of out-of-plane excitons
in polycyclic aromatic hydrocarbons. In this article, we develop a novel
concept of light emission and optical gain from simple vertical
graphene/dielectric tunnel junctions. It is theoretically shown that the
possible optical gain or emission spectrum will be easily tunable by the
applied voltage. We present details of quantum mechanical calculations and
perform an exact analysis of field-assisted tunneling using transfer matrices
combined with expansion on Airy's functions.


title: Extended Fourier analysis of signals

abstract:
  This summary of the doctoral thesis is created to emphasize the close
connection of the proposed spectral analysis method with the Discrete Fourier
Transform (DFT), the most extensively studied and frequently used approach in
the history of signal processing. It is shown that in a typical application
case, where uniform data readings are transformed to the same number of
uniformly spaced frequencies, the results of the classical DFT and proposed
approach coincide. The difference in performance appears when the length of the
DFT is selected to be greater than the length of the data. The DFT solves the
unknown data problem by padding readings with zeros up to the length of the
DFT, while the proposed Extended DFT (EDFT) deals with this situation in a
different way, it uses the Fourier integral transform as a target and optimizes
the transform basis in the extended frequency range without putting such
restrictions on the time domain. Consequently, the Inverse DFT (IDFT) applied
to the result of EDFT returns not only known readings, but also the
extrapolated data, where classical DFT is able to give back just zeros, and
higher resolution are achieved at frequencies where the data has been
successfully extended. It has been demonstrated that EDFT able to process data
with missing readings or gaps inside or even nonuniformly distributed data.
Thus, EDFT significantly extends the usability of the DFT-based methods, where
previously these approaches have been considered as not applicable. The EDFT
founds the solution in an iterative way and requires repeated calculations to
get the adaptive basis, and this makes it numerical complexity much higher
compared to DFT. This disadvantage was a serious problem in the 1990s, when the
method has been proposed. Fortunately, since then the power of computers has
increased so much that nowadays EDFT application could be considered as a real
alternative.


title: Entanglement of Open Quantum Systems in Noninertial Frames

abstract:
  We study the effects of decoherence on the entanglement generated by Unruh
effect in accelerated frames by using various combinations of an amplitude
damping channel, a phase damping channel and a depolarizing channel in the form
of multilocal and collective environments. Using concurrence as entanglement
quantifier, we show that the occurrence of entanglement sudden death (ESD)
depends on different combinations of the channels. The ESD can be avoided under
a particular configuration of the channels. We show that the channels can be
used to distinguish between a moving and a stationary frame.


title: E8 duality and dual gravity

abstract:
  We construct the non-linear realisation of the E8 motion group and compare
this with the bosonic sector of eleven dimensional supergravity. The
construction naturally leads to the introduction of a new potential field. We
identify this new field with the dual gravity field by considering the
reduction of the eleven-dimensional theory to three dimensions.


title:
The Einstein-Hilbert action of the space of holomorphic maps from S^2 to
  CP^k

abstract:
  Let $\mathcal{H}_{n,k}(\Sigma)$ be the space of degree $n\geq 1$ holomorphic
maps from a compact Riemann surface $\Sigma $ to $\mathbb{C}P^k$. In the case
$\Sigma=S^2$ and $n=1$, the $L^2$ metric on $\mathcal{H}_{1,k}(S^2)$ was
computed exactly by Speight. In this paper, the Ricci curvature tensor and the
scalar curvature on $\mathcal{H}_{1,k}(S^2)$ are determined explicitly for
$k\geq 2$. An exact direct computation of the Einstein-Hilbert action with
respect to the $L^2$ metric on $\mathcal{H}_{1,k}(S^2)$ is made and shown to
coincide with a formula conjectured by Baptista.


title: Muller's ratchet clicks in finite time

abstract:
  We consider the accumulation of deleterious mutations in an asexual
population, a phenomenon known as Muller's ratchet, using the continuous time
model proposed in Etheridge et all. \cite{epw}. We show that for any parameter
$\lambda>0$ (the rate at which mutations occur), for any $\alpha>0$ (the
toxicity of the mutations) and for any size $N>0$ of the population, the
ratchet clicks a.s. in finite time. That is to say the minimum number of
deleterious mutations in the population goes to infinity a.s.


title:
Strain effects to optimize the thermoelectric properties of hole-doped
  La$_2$NiO$_{4+\delta}$ via ab initio calculations

abstract:
  Thermoelectric properties of the system La$_2$NiO$_{4+\delta}$ have been
recently discussed [Phys. Rev. B 86, 165114 (2012)] via ab initio calculations.
An optimum hole-doping value was obtained with reasonable thermopower and
thermoelectric figure of merit being calculated. Here, a large increase in the
thermoelectric performance through lattice strain and the corresponding atomic
relaxations is predicted. This increase would be experimentally attainable via
growth in thin films of the material on top of different substrates. A small
tensile strain would produce large thermoelectric figures of merit at high
temperatures, $zT$ $\sim$ 1 in the range of oxygen excess $\delta$ $\sim$ 0.05
- 0.10 and in-plane lattice parameter in the range 3.95 - 4.05 \AA. In that
relatively wide range of parameters, thermopower values close to 200 $\mu$V/K
are obtained. The best performance of this compound is expected to occur in the
high temperature limit.


title:
Locating the Gamma-ray Flaring Emission of Blazar AO 0235+164 in the Jet
  at Parsec Scales Through Multi Spectral Range Monitoring

abstract:
  We present observations of a major outburst at centimeter, millimeter,
optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164
in 2008. We analyze the timing of multi-waveband variations in the flux and
linear polarization, as well as changes in Very Long Baseline Array (VLBA)
images at 7mm with ~0.15 milliarcsecond resolution. The association of the
events at different wavebands is confirmed at high statistical significance by
probability arguments and Monte-Carlo simulations. A series of sharp peaks in
optical linear polarization, as well as a pronounced maximum in the 7mm
polarization of a superluminal jet knot, indicate rapid fluctuations in the
degree of ordering of the magnetic field. These results lead us to conclude
that the outburst occurred in the jet both in the quasi-stationary core and in
the superluminal knot, both at >12 parsecs downstream of the supermassive black
hole. We interpret the outburst as a consequence of the propagation of a
disturbance, elongated along the line of sight by light-travel time delays,
that passes through a standing recollimation shock in the core and propagates
down the jet to create the superluminal knot. The multi-wavelength light curves
vary together on long time-scales (months/years), but the correspondence is
poorer on shorter time-scales. This, as well as the variability of the
polarization and the dual location of the outburst, agrees with the
expectations of a multi-zone emission model in which turbulence plays a major
role in modulating the synchrotron and inverse Compton fluxes.


title: The rate of escape of the most visited site of Brownian motion

abstract:
  Let $\{L^z_t\}$ be the jointly continuous local times of a one-dimensional
Brownian motion and let $L^*_t=\sup_{z\in \mathbb R} L^z_t$. Let $V_t$ be any
point $z$ such that $L^z_t=L^*_t$, a most visited site of Brownian motion. We
prove that if $\gamma>1$, then\[\liminf_{t\to \infty} \frac{|V_t|}{\sqrt
t/(\log t)^\gamma}=\infty, \qquad \mbox{a.s.}, \] with an analogous result for
simple random walk. This proves a conjecture of Lifshits and Shi.


title: Socially stable matchings in the Hospitals / Residents problem

abstract:
  In the Hospitals/Residents (HR) problem, agents are partitioned into
hospitals and residents. Each agent wishes to be matched to an agent in the
other set and has a strict preference over these potential matches. A matching
is stable if there are no blocking pairs, i.e., no pair of agents that prefer
each other to their assigned matches. Such a situation is undesirable as it
could lead to a deviation in which the blocking pair form a private arrangement
outside the matching. This however assumes that the blocking pair have social
ties or communication channels to facilitate the deviation. Relaxing the
stability definition to take account of the potential lack of social ties
between agents can yield larger stable matchings.
  In this paper, we define the Hospitals/Residents problem under Social
Stability (HRSS) which takes into account social ties between agents by
introducing a social network graph to the HR problem. Edges in the social
network graph correspond to resident-hospital pairs in the HR instance that
know one another. Pairs that do not have corresponding edges in the social
network graph can belong to a matching M but they can never block M. Relative
to a relaxed stability definition for HRSS, called social stability, we show
that socially stable matchings can have different sizes and the problem of
finding a maximum socially stable matching is NP-hard, though approximable
within 3/2. Furthermore we give polynomial time algorithms for three special
cases of the problem.


title:
Polynomial-time T-depth Optimization of Clifford+T circuits via Matroid
  Partitioning

abstract:
  Most work in quantum circuit optimization has been performed in isolation
from the results of quantum fault-tolerance. Here we present a polynomial-time
algorithm for optimizing quantum circuits that takes the actual implementation
of fault-tolerant logical gates into consideration. Our algorithm
re-synthesizes quantum circuits composed of Clifford group and T gates, the
latter being typically the most costly gate in fault-tolerant models, e.g.,
those based on the Steane or surface codes, with the purpose of minimizing both
T-count and T-depth. A major feature of the algorithm is the ability to
re-synthesize circuits with additional ancillae to reduce T-depth at
effectively no cost. The tested benchmarks show up to 65.7% reduction in
T-count and up to 87.6% reduction in T-depth without ancillae, or 99.7%
reduction in T-depth using ancillae.


title: Orientation and Connectivity Based Criteria for Asymptotic Consensus

abstract:
  In this article, we establish orientation and connectivity based criteria for
the agreement algorithm to achieve asymptotic consensus in the context of
time-varying topology and communication delays. These criteria unify and extend
many earlier convergence results on the agreement algorithm for deterministic
and discrete-time multiagent systems.


title: Bubbles, Jumps, and Scaling from Properly Anticipated Prices

abstract:
  Prices in financial markets exhibit extreme jumps far more often than can be
accounted for by external news. Further, magnitudes of price changes are
correlated over long times. These so called stylized facts are quantified by
scaling laws similar to, for example, turbulent fluids. They are believed to
reflect the complex interactions of heterogenous agents which give rise to
irrational herding. Therefore, the stylized facts have been argued to provide
evidence against the efficient market hypothesis which states that prices
rapidly reflect available information and therefore are described by a
martingale. Here we show, that in very simple bidding processes efficiency is
not opposed to, but causative to scaling properties observed in real markets.
Thereby, we link the stylized facts not only to price efficiency, but also to
the economic theory of rational bubbles. We then demonstrate effects predicted
from our normative model in the dynamics of groups of real human subjects
playing a modified minority game. An extended version of the latter can be
played online at seesaw.neuro.uni-bremen.de.


title: Optimal dynamical decoupling in the presence of colored control noise

abstract:
  An optimal dynamical decoupling of a quantum system coupled to a noisy
environment must take into account also the imperfections of the control
pulses. We present a new formalism which describes, in a closed-form
expression, the evolution of the system, including the spectral function of
both the environment and control noise. We show that by measuring these
spectral functions, our expression can be used to optimize the decoupling pulse
sequence. We demonstrate this approach with an ensemble of optically trapped
ultra-cold Rubidium atoms, and use quantum process tomography to identify the
effect of the environment and control noise. Our approach is applicable and
important for any realistic implementation of quantum information processing.


title:
Excitation energy transfer efficiency: equivalence of transient and
  stationary setting and the absence of non-Markovian effects

abstract:
  We analyze efficiency of excitation energy transfer in photosynthetic
complexes in transient and stationary setting. In the transient setting the
absorption process is modeled as an individual event resulting in a subsequent
relaxation dynamics. In the stationary setting the absorption is a continuous
stationary process, leading to the nonequilibrium steady state. We show that,
as far as the efficiency is concerned, both settings can be considered to be
the same, as they result in almost identical efficiency. We also show that
non-Markovianity has no effect on the resulting efficiency, i.e., corresponding
Markovian dynamics results in identical efficiency. Even more, if one maps
dynamics to appropriate classical rate equations, the same efficiency as in
quantum case is obtained.


title: Double-humped Super-luminous Supernovae

abstract:
  Super-luminous supernova (SLSN) are supernovae showing extreme properties in
their light-curves: high peak luminosities (more than 10 times brighter than
bright SN Ia), and long durations. Several mechanisms have been proposed for
SLSN, such as pair instability SN of a massive progenitor, interaction of the
ejecta with a massive circumstellar shell, and the dual-shock quark nova (dsQN)
model. The dual-shock quark nova model is unique in that it predicts a normal
SN event will be seen about 10 days prior to the main SLSN event. The dsQN
model is described here and shown that it is consistent with the light curve of
the one currently known double-humped SLSN, 2006oz.


title: Finding Zeros: Greedy Detection of Holes

abstract:
  In this paper, motivated by the setting of white-space detection [1], we
present theoretical and empirical results for detection of the zero-support E
of x \in Cp (xi = 0 for i \in E) with reduced-dimension linear measurements. We
propose two low- complexity algorithms based on one-step thresholding [2] for
this purpose. The second algorithm is a variant of the first that further
assumes the presence of group-structure in the target signal [3] x. Performance
guarantees for both algorithms based on the worst- case and average coherence
(group coherence) of the measurement matrix is presented along with the
empirical performance of the algorithms.


title:
Measurement of Cosmic Ray Spectrum and Anisotropy with the ARGO-YBJ
  experiment

abstract:
  The combined measurement of the cosmic ray (CR) energy spectrum and
anisotropy in their arrival direction distribution needs the knowledge of the
elemental composition of the radiation to discriminate between different origin
and propagation models. Important information on the CR mass composition can be
obtained studying the EAS muon content through the measurement of the CR rate
at different zenith angles.
  In this paper we report on the observation of the anisotropy of galactic CRs
at different angular scales with the ARGO-YBJ experiment. We report also on the
study of the primary CR rate for different zenith angles. The light component
(p+He) has been selected and its energy spectrum measured in the energy range
(5 - 200) TeV for quasi-vertical events. With this analysis for the first time
a ground-based measurement of the CR spectrum overlaps data obtained with
direct methods for more than one energy decade, thus providing a solid
anchorage to the CR spectrum measurements carried out by EAS arrays in the knee
region.
  Finally, a preliminary study of the non-attenuated shower component at a
zenith angle $\theta >$ 70$^{\circ}$ (through the observation of the so-called
horizantal air showers) is presented.


title: Mott-Hubbard transition in V2O3 revisited

abstract:
  The isostructural metal-insulator transition in Cr-doped V2O3 is the textbook
example of a Mott-Hubbard transition between a paramagnetic metal and a
paramagnetic insulator. We review recent theoretical calculations as well as
experimental findings which shed new light on this famous transition. In
particular, the old paradigm of a doping-pressure equivalence does not hold,
and there is a microscale phase separation for Cr-doped V2O3.


title: Physics behind the minimum of relative entropy measures for correlations

abstract:
  The relative entropy of a correlated state and an uncorrelated reference
state is a reasonable measure for the degree of correlations. A key question is
however which uncorrelated state to compare to. The relative entropy becomes
minimal for the uncorrelated reference state that has the same one-particle
density matrix as the correlated state. Hence, this particular measure, coined
nonfreeness, is unique and reasonable. We demonstrate that for relevant
physical situations, such as finite temperatures or a correlation enhanced
orbital splitting, other choices of the uncorrelated state, even educated
guesses, overestimate correlations.

categories: cond-mat.str-el cond-mat.mtrl-sci cond-mat.stat-mech quant-ph


title:
Star-forming regions of the Aquila rift cloud complex. I. NH3 tracers of
  dense molecular cores

abstract:
  (Abridged) Aims. In the present part of our survey we search for ammonia
emitters in the Aquila rift complex which trace the densest regions of
molecular clouds. Methods. From a CO survey carried out with the Delingha 14-m
telescope we selected ~150 targets for observations in other molecular lines.
Here we describe the mapping observations in the NH3(1,1) and (2,2) inversion
lines of the first 49 sources performed with the Effelsberg 100-m telescope.
Results. The NH3(1,1) and (2,2) emission lines are detected in 12 and 7
sources, respectively. Among the newly discovered NH3 sources, our sample
includes the following well-known clouds: the starless core L694-2, the Serpens
cloud Cluster B, the Serpens dark cloud L572, the filamentary dark cloud L673,
the isolated protostellar source B335, and the complex star-forming region
Serpens South. Angular sizes between 40" and 80" (~0.04-0.08 pc) are observed
for compact starless cores but as large as 9' (~0.5 pc) for filamentary dark
clouds. The measured kinetic temperatures of the clouds lie between 9K and 18K.
From NH3 excitation temperatures of 3-8K we determine H2 densities with typical
values of ~(0.4-4) 10^4 cm^-3. The masses of the mapped cores range between
~0.05 and ~0.5M_solar. The relative ammonia abundance, X= [NH3]/[H2], varies
from 10^-7 to 5 10^-7 with the mean <X> = (2.7+/-0.6) 10^-7 (estimated from
spatially resolved cores assuming the filling factor eta = 1). In two clouds,
we observe kinematically split NH3 profiles separated by ~1 km/s. The splitting
is most likely due to bipolar molecular outflows for one of which we determine
an acceleration of <~ 0.03 km/s/yr. A starless core with significant rotational
energy is found to have a higher kinetic temperature than the other ones which
is probably caused by magnetic energy dissipation.


title:
Dimensional reduction and its breakdown in the 3-dimensional long-range
  random field Ising model

abstract:
  We investigate dimensional reduction, the property that the critical behavior
of a system in the presence of quenched disorder in dimension d is the same as
that of its pure counterpart in d-2, and its breakdown in the case of the
random-field Ising model in which both the interactions and the correlations of
the disorder are long-ranged, i.e. power-law decaying. To some extent the
power-law exponents play the role of spatial dimension in a short-range model,
which allows us to probe the theoretically predicted existence of a nontrivial
critical value separating a region where dimensional reduction holds from one
where it is broken, while still considering the physical dimension d=3. By
extending our recently developed approach based on a nonperturbative functional
renormalization group combined with a supersymmetric formalism, we find that
such a critical value indeed exists, provided one chooses a specific relation
between the decay exponents of the interactions and of the disorder
correlations. This transition from dimensional reduction to its breakdown
should therefore be observable in simulations and numerical analyses, if not
experimentally.


title:
Mining Representative Unsubstituted Graph Patterns Using Prior
  Similarity Matrix

abstract:
  One of the most powerful techniques to study protein structures is to look
for recurrent fragments (also called substructures or spatial motifs), then use
them as patterns to characterize the proteins under study. An emergent trend
consists in parsing proteins three-dimensional (3D) structures into graphs of
amino acids. Hence, the search of recurrent spatial motifs is formulated as a
process of frequent subgraph discovery where each subgraph represents a spatial
motif. In this scope, several efficient approaches for frequent subgraph
discovery have been proposed in the literature. However, the set of discovered
frequent subgraphs is too large to be efficiently analyzed and explored in any
further process. In this paper, we propose a novel pattern selection approach
that shrinks the large number of discovered frequent subgraphs by selecting the
representative ones. Existing pattern selection approaches do not exploit the
domain knowledge. Yet, in our approach we incorporate the evolutionary
information of amino acids defined in the substitution matrices in order to
select the representative subgraphs. We show the effectiveness of our approach
on a number of real datasets. The results issued from our experiments show that
our approach is able to considerably decrease the number of motifs while
enhancing their interestingness.


title:
A dark-field microscope for background-free detection of resonance
  fluorescence from single semiconductor quantum dots operating in a
  set-and-forget mode

abstract:
  Optically active quantum dots, for instance self-assembled InGaAs quantum
dots, are potentially excellent single photon sources. The fidelity of the
single photons is much improved using resonant rather than non-resonant
excitation. With resonant excitation, the challenge is to distinguish between
resonance fluorescence and scattered laser light. We have met this challenge by
creating a polarization-based dark-field microscope to measure the resonance
fluorescence from a single quantum dot at low temperature. We achieve a
suppression of the scattered laser exceeding a factor of 10^7 and
background-free detection of resonance fluorescence. The same optical setup
operates over the entire quantum dot emission range 920-980 nm and also in high
magnetic fields. The major development is the outstanding long-term stability:
once the dark-field point has been established, the microscope operates for
days without alignment. The mechanical and optical design of the microscope is
presented, as well as exemplary resonance fluorescence spectroscopy results on
individual quantum dots to underline the microscope's excellent performance.


title: Orbital anisotropy in cosmological haloes revisited

abstract:
  The velocity anisotropy of particles inside dark matter (DM) haloes is an
important physical quantity, which is required for the accurate modelling of
mass profiles of galaxies and clusters of galaxies. It is typically measured
using the ratio of the radial-to-tangential velocity dispersions at a given
distance from the halo centre. However, this measure is insufficient to
describe the dynamics of realistic haloes, which are typically quite elongated.
Studying the velocity distribution in massive DM haloes in cosmological
simulations, we find that in the inner parts of the haloes the local velocity
ellipsoids are strongly aligned with the major axis of the halo, the alignment
being stronger for more relaxed haloes. In the outer regions of the haloes, the
alignment becomes gradually weaker and the orientation is more random. These
two distinct regions of different degree of the alignment coincide with two
characteristic regimes of the DM density profile: shallower and steeper than
\rho r^{-2}. This alignment of the local velocity ellipsoids requires
reinterpretation of features found in measurements based on the spherically
averaged ratio of the radial-to-tangential velocity dispersions. In particular,
we show that the velocity distribution in the central halo regions is highly
anisotropic. For cluster-size haloes with mass 10^{14}-10^{15} h^-1 Msun, the
velocity anisotropy along the major axis is nearly independent of radius and is
equal to \beta=1-\sigma^2_{perp}/\sigma^2_{radial}=0.4, which is significantly
larger than the previously estimated spherically averaged velocity anisotropy.
The alignment of density and velocity anisotropies, and the radial trends may
also have some implications for the mass modelling based on kinematical data of
such objects as galaxy clusters or dwarf spheroidals, where the orbital
anisotropy is a key element in an unbiased mass inference.


title:
Polariton excitation in epsilon-near-zero slabs: transient trapping of
  slow light

abstract:
  We numerically investigate the propagation of a spatially localized and
quasi-monochromatic electromagnetic pulse through a slab with Lorentz
dielectric response in the epsilon-near-zero regime, where the real part of the
permittivity vanishes at the pulse carrier frequency. We show that the pulse is
able to excite a set of virtual polariton modes supported by the slab, the
excitation undergoing a generally slow damping due to absorption and radiation
leakage. Our numerical and analytical approaches indicate that in its transient
dynamics the electromagnetic field displays the very same enhancement of the
field component perpendicular to the slab, as in the monochromatic regime. The
transient trapping is inherently accompanied by a significantly reduced group
velocity ensuing from the small dielectric permittivity, thus providing a novel
platform for achieving control and manipulation of slow light.


title: Wetting in electrolyte solutions

abstract:
  Wetting of a charged substrate by an electrolyte solution is investigated by
means of classical density functional theory applied to a lattice model. Within
the present model the pure, i.e., salt-free solvent, for which all interactions
are of the nearest-neighbor type only, exhibits a second-order wetting
transition for all strengths of the substrate-particle and the
particle-particle interactions for which the wetting transition temperature is
nonzero. The influences of the substrate charge density and of the ionic
strength on the wetting transition temperature and on the order of the wetting
transition are studied. If the substrate is neutral, the addition of salt to
the solvent changes neither the order nor the transition temperature of the
wetting transition of the system. If the surface charge is nonzero, upon adding
salt this continuous wetting transition changes to first-order within the wide
range of substrate surface charge densities and ionic strengths studied here.
As the substrate surface charge density is increased, at fixed ionic strength,
the wetting transition temperature decreases and the prewetting line associated
with the first-order wetting transition becomes longer. This decrease of the
wetting transition temperature upon increasing the surface charge density
becomes more pronounced by decreasing the ionic strength.


title: Structural Tractability of Counting of Solutions to Conjunctive Queries

abstract:
  In this paper we explore the problem of counting solutions to conjunctive
queries. We consider a parameter called the \emph{quantified star size} of a
formula $\varphi$ which measures how the free variables are spread in
$\varphi$. We show that for conjunctive queries that admit nice decomposition
properties (such as being of bounded treewidth or generalized hypertree width)
bounded quantified star size exactly characterizes the classes of queries for
which counting the number of solutions is tractable. This also allows us to
fully characterize the conjunctive queries for which counting the solutions is
tractable in the case of bounded arity. To illustrate the applicability of our
results, we also show that computing the quantified star size of a formula is
possible in time $n^{O(k)}$ for queries of generalized hypertree width $k$.
Furthermore, quantified star size is even fixed parameter tractable
parameterized by some other width measures, while it is $\W{1}$-hard for
generalized hypertree width and thus unlikely to be fixed parameter tractable.
We finally show how to compute an approximation of quantified star size in
polynomial time where the approximation ratio depends on the width of the
input.


title:
Adaptive Non-myopic Quantizer Design for Target Tracking in Wireless
  Sensor Networks

abstract:
  In this paper, we investigate the problem of nonmyopic (multi-step ahead)
quantizer design for target tracking using a wireless sensor network. Adopting
the alternative conditional posterior Cramer-Rao lower bound (A-CPCRLB) as the
optimization metric, we theoretically show that this problem can be temporally
decomposed over a certain time window. Based on sequential Monte-Carlo methods
for tracking, i.e., particle filters, we design the local quantizer adaptively
by solving a particlebased non-linear optimization problem which is well suited
for the use of interior-point algorithm and easily embedded in the filtering
process. Simulation results are provided to illustrate the effectiveness of our
proposed approach.


title: Towards the Future of Supernova Cosmology

abstract:
  For future surveys, spectroscopic follow-up for all supernovae will be
extremely difficult. However, one can use light curve fitters, to obtain the
probability that an object is a Type Ia. One may consider applying a
probability cut to the data, but we show that the resulting non-Ia
contamination can lead to biases in the estimation of cosmological parameters.
A different method, which allows the use of the full dataset and results in
unbiased cosmological parameter estimation, is Bayesian Estimation Applied to
Multiple Species (BEAMS). BEAMS is a Bayesian approach to the problem which
includes the uncertainty in the types in the evaluation of the posterior. Here
we outline the theory of BEAMS and demonstrate its effectiveness using both
simulated datasets and SDSS-II data. We also show that it is possible to use
BEAMS if the data are correlated, by introducing a numerical marginalisation
over the types of the objects. This is largely a pedagogical introduction to
BEAMS with references to the main BEAMS papers.


title: Ubiquitous HealthCare in Wireless Body Area Networks - A Survey

abstract:
  Advances in wireless communication, system on chip and low power sensor nodes
allowed realization of Wireless Body Area Network (WBAN). WBAN comprised of
tiny sensors, which collect information of patient's vital signs and provide a
real time feedback. In addition, WBAN also supports many applications including
Ubiquitous HealthCare (UHC), entertainment, gaming, military, etc. UHC is
required by elderly people to facilitate them with instant monitoring anywhere
they move around. In this paper, different standards used in WBAN were also
discussed briefly. Path loss in WBAN and its impact on communication was
presented with the help of simulations, which were performed for different
models of In-Body communication and different factors (such as, attenuation,
frequency, distance etc) influencing path loss in On-Body communications.


title:
An eclipsing binary distance to the Large Magellanic Cloud accurate to 2
  per cent

abstract:
  In the era of precision cosmology it is essential to determine the Hubble
Constant with an accuracy of 3% or better. Currently, its uncertainty is
dominated by the uncertainty in the distance to the Large Magellanic Cloud
(LMC) which as the second nearest galaxy serves as the best anchor point of the
cosmic distance scale. Observations of eclipsing binaries offer a unique
opportunity to precisely and accurately measure stellar parameters and
distances. The eclipsing binary method was previously applied to the LMC but
the accuracy of the distance results was hampered by the need to model the
bright, early-type systems used in these studies. Here, we present distance
determinations to eight long-period, late- type eclipsing systems in the LMC
composed of cool giant stars. For such systems we can accurately measure both
the linear and angular sizes of their components and avoid the most important
problems related to the hot early-type systems. Our LMC distance derived from
these systems is demonstrably accurate to 2.2 % (49.97 +/- 0.19 (statistical)
+/- 1.11 (systematic) kpc) providing a firm base for a 3 % determination of the
Hubble Constant, with prospects for improvement to 2 % in the future.


title: Numerical models for the circumstellar medium around Betelgeuse

abstract:
  The nearby red supergiant (RSG) Betelgeuse has a complex circumstellar medium
out to at least 0.5 parsecs from its surface, shaped by its mass-loss history
within the past 0.1 Myr, its environment, and its motion through the
interstellar medium (ISM). In principle its mass-loss history can be
constrained by comparing hydrodynamic models with observations. Observations
and numerical simulations indicate that Betelgeuse has a very young bow shock,
hence the star may have only recently become a RSG. To test this possibility we
calculated a stellar evolution model for a single star with properties
consistent with Betelgeuse. We incorporated the resulting evolving stellar wind
into 2D hydrodynamic simulations to model a runaway blue supergiant (BSG)
undergoing the transition to a RSG near the end of its life. The collapsing BSG
wind bubble induces a bow shock-shaped inner shell which at least superficially
resembles Betelgeuse's bow shock, and has a similar mass. Surrounding this is
the larger-scale retreating bow shock generated by the now defunct BSG wind's
interaction with the ISM. We investigate whether this outer shell could explain
the bar feature located (at least in projection) just in front of Betelgeuse's
bow shock.


title: A proof of Perko's conjectures for the Bogdanov-Takens system

abstract:
  The Bogdanov-Takens system has at most one limit cycle and, in the parameter
space, it exists between a Hopf and a saddle-loop bifurcation curves. The aim
of this paper is to prove the Perko's conjectures about some analytic
properties of the saddle-loop bifurcation curve. Moreover, we provide sharp
piecewise algebraic upper and lower bounds for this curve.


title: Ancilla Driven Quantum Computation with arbitrary entangling strength

abstract:
  We extend the model of Ancilla Driven Quantum Computation (ADQC) by
considering gates with arbitrary entangling power. By giving up stepwise
determinism, universal QC can still be achieved through a variable length
sequence of single qubit gates and probabilistic "repeat-until-success"
entangling operations. This opens up a new range of possible physical
implementations as well as shedding light on the sets of resources sufficient
for universal QC.


title: Recent achievements in ab initio modelling of liquid water

abstract:
  The application of newly developed first-principle modeling techniques to
liquid water deepens our understanding of the microscopic origins of its
unusual macroscopic properties and behaviour. Here, we review two novel ab
initio computational methods: second-generation Car-Parrinello molecular
dynamics and decomposition analysis based on absolutely localized molecular
orbitals. We show that these two methods in combination not only enable ab
initio molecular dynamics simulations on previously inaccessible time and
length scales, but also provide unprecedented insights into the nature of
hydrogen bonding between water molecules. We discuss recent applications of
these methods to water clusters and bulk water.

categories: physics.chem-ph cond-mat.soft cond-mat.stat-mech physics.bio-ph physics.comp-ph


title: On the representation type of a projectiva variety

abstract:
  Let X be a smooth arithmetically Cohen-Macaulay subvariety of Pn. We prove
that the restriction to X of the Veronese 3-uple embedding of Pn embeds X as a
variety of wild representation type.


title: Perfect squares have at most five divisors close to its square root

abstract:
  In this paper, we consider a conjecture of Erd\H{o}s and Rosenfeld when the
number is a perfect square. In particular, we show that every perfect square
$n$ can have at most five divisors between $\sqrt{n} - c \sqrt[4]{n}$ and
$\sqrt{n} + c \sqrt[4]{n}$.


title: Knots in collapsible and non-collapsible balls

abstract:
  We construct the first explicit example of a simplicial 3-ball B_{15,66} that
is not collapsible. It has only 15 vertices. We exhibit a second 3-ball
B_{12,38} with 12 vertices that is collapsible and evasive, but not shellable.
Finally, we present the first explicit triangulation of a 3-sphere S_{18, 125}
(with only 18 vertices) that is not locally constructible. All these examples
are based on knotted subcomplexes with only three edges; the knots are the
trefoil, the double trefoil, and the triple trefoil, respectively. The more
complicated the knot is, the more distant the triangulation is from being
polytopal, collapsible, etc. Further consequences of our work are:
  (1) Unshellable 3-spheres may have vertex-decomposable barycentric
subdivisions.
  (This shows the strictness of an implication proven by Billera and Provan.)
  (2) For d-balls, vertex-decomposable implies non-evasive implies collapsible,
and for d=3 all implications are strict.
  (This answers a question by Barmak.)
  (3) Locally constructible 3-balls may contain a double trefoil knot as a
3-edge subcomplex.
  (This improves a result of Benedetti and Ziegler.)
  (4) Rudin's ball is non-evasive.


title:
Application of the SP theory of intelligence to the understanding of
  natural vision and the development of computer vision

abstract:
  The SP theory of intelligence aims to simplify and integrate concepts in
computing and cognition, with information compression as a unifying theme. This
article discusses how it may be applied to the understanding of natural vision
and the development of computer vision. The theory, which is described quite
fully elsewhere, is described here in outline but with enough detail to ensure
that the rest of the article makes sense.
  Low level perceptual features such as edges or corners may be identified by
the extraction of redundancy in uniform areas in a manner that is comparable
with the run-length encoding technique for information compression.
  The concept of multiple alignment in the SP theory may be applied to the
recognition of objects, and to scene analysis, with a hierarchy of parts and
sub-parts, and at multiple levels of abstraction.
  The theory has potential for the unsupervised learning of visual objects and
classes of objects, and suggests how coherent concepts may be derived from
fragments.
  As in natural vision, both recognition and learning in the SP system is
robust in the face of errors of omission, commission and substitution.
  The theory suggests how, via vision, we may piece together a knowledge of the
three-dimensional structure of objects and of our environment, it provides an
account of how we may see things that are not objectively present in an image,
and how we recognise something despite variations in the size of its retinal
image. And it has things to say about the phenomena of lightness constancy and
colour constancy, the role of context in recognition, and ambiguities in visual
perception.
  A strength of the SP theory is that it provides for the integration of vision
with other sensory modalities and with other aspects of intelligence.


title:
Energy Efficient MAC Protocols in Wireless Body Area Sensor Networks -A
  Survey

abstract:
  In this paper, we first presented an analytically discussion about energy
efficiency of Medium Access Control (MAC) protocols for Wireless Body Area
Sensor Networks (WBASNs). For this purpose, different energy efficient MAC
protocols with their respective energy optimization techniques; Low Power
Listening (LPL), Scheduled Contention and Time Division Multiple Access (TDMA),
are elaborated. We also analytically compared path loss models for In-body,
On-body and Off-body communications in WBASNs. These three path loss scenarios
are simulated in MATLAB and results shown that path loss is more in In-body
communication because of less energy level to take care of tissues and organs
located inside human body. Secondly, power model for WBASNs of Carrier Sense
Multiple Access with Collision Avoidance (CSMA/CA) and beacon mode is also
presented. MATLAB simulations results shown that power of CSMA/CA mode is less
as compared to beacon mode. Finally, we suggested that hybrid mode is more
useful to achieve optimization in power consumption, which consequently results
in high energy efficiency.


title: About the proof of the Collatz conjecture

abstract:
  I want to show one possibility to proof the Collatz conjecture, also called
3n+1 conjecture, for any natural number N. For this, I limit my analysis on the
direct odd follower of every natural odd number and show the connections
between the already by one reached numbers and their followers, to find an
recurrence over all ranges [1,N_{i}], to proof the conjecture.


title:
An analytical continuation approach for evaluating emission lineshapes
  of molecular aggregates and the adequacy of multichromophoric F\"orster
  theory

abstract:
  In large photosynthetic chromophore-protein complexes not all chromophores
are coupled strongly, and thus the situation is well described by formation of
delocalized states in certain domains of strongly coupled chromophores. In
order to describe excitation energy transfer among different domains without
performing extensive numerical calculations,one of the most popular techniques
is a generalization of Forster theory to multichromophoric aggregates
(generalized Forster theory) proposed by Sumi [J.Phys.Chem.B,103,252(1999)] and
Scholes and Fleming [J.Phys.Chem.B 104,1854(2000)]. The aim of this paper is
twofold. In the first place, by means of analytic continuation and a time
convolutionless quantum master equation approach, a theory of emission
lineshape of multichromophoric systems or molecular aggregates is proposed. In
the second place,a comprehensive framework that allows for a clear,compact and
effective study of the multichromophoric approach in the full general version
proposed by Jang, Newton and Silbey [Phys. Rev. Lett.,92,218301,(2004)] is
developed. We apply the present theory to simple paradigmatic systems and we
show: the effectiveness of time-convolutionless techniques in deriving
lineshape operators; how the multichromophoric approach can give significant
improvements in the determination of energy transfer rates in particular when
the systems under study are not the purely Forster regime. The presented scheme
allows for an effective implementation of the multichromophoric Forster
approach which may be of use for simulating energy transfer dynamics in large
photosynthetic aggregates, for which massive computational resources are
usually required. Furthermore,our method allows for a systematic comparison of
multichromophoric Foster and generalized Forster theories and for a clear
understanding of their respective limits of validity.


title:
On the equivalence of Lambda(t) and gravitationally induced particle
  production cosmologies

abstract:
  The correspondence between cosmological models powered by a decaying vacuum
energy density and gravitationally induced particle production is investigated.
Although being physically different in the physics behind them we show that
both classes of cosmologies under certain conditions can exhibit the same
dynamic and thermodynamic behavior. Our method is applied to obtain three
specific models that may be described either as Lambda(t)CDM or gravitationally
induced particle creation cosmologies. In the point of view of particle
production models, the later class of cosmologies can be interpreted as a kind
of one-component unification of the dark sector. By using current type Ia
supernovae data, recent estimates of the cosmic microwave background shift
parameter and baryon acoustic oscillations measurements we also perform a
statistical analysis to test the observational viability within the two
equivalent classes of models and we obtain the best-fit of the free parameters.
By adopting the Akaike information criterion we also determine the rank of the
models considered here. Finally, the particle production cosmologies (and the
associated decaying Lambda(t)-models) are modeled in the framework of field
theory by a phenomenological scalar field model.


title: COMPASS results on Collins and Sivers asymmetries for charged hadrons

abstract:
  The study of transverse spin and transverse momentum effects is an important
part of the scientific program of COMPASS, a fixed target experiment at the
CERN SPS taking data since 2002. The studies are carried on by measuring the
hadrons produced in deep inelastic scattering (DIS) of 160 GeV/c muons off
different targets. Among the possible asymmetries in the hadron azimuthal
distributions, particularly interesting are the Collins and Sivers asymmetries
which the COMPASS Collaboration has measured using transversely polarised
deuteron and proton targets. The new results for charged pions and kaons
obtained from the 2010 run with a transversely polarised proton target are
presented.


title: Geometrothermodynamics of Myers-Perry black holes

abstract:
  We consider the thermodynamics and Geometrothermodynamics of the Myers-Perry
black holes in five dimensions for three different cases, depending on the
values of the angular momenta. We follow Davies approach to study the
thermodynamics of black holes and find a non-trivial thermodynamic structure in
all cases, which is fully reproduced by the analysis performed with the
techniques of Geometrothermodynamics. Moreover, we observe that in the cases
when only one angular momentum is present or the two angular momenta are fixed
to be equal, i.e. when the thermodynamic system is two dimensional, there is a
complete agreement between the divergences of the generalized susceptibilities
and the singularities of the equilibrium manifold, whereas when the two angular
momenta are fully independent, that is, when the thermodynamic system is three
dimensional, additional singularities in the curvature appear. However, we
prove that such singularities are due to the changing from a stable phase to an
unstable one.


title: Bosonic (meta)stabilization of cosmic string loops

abstract:
  We consider the possibility of a bosonic (meta)stabilization of a cosmic
gauge string loop due to the presence of a gas of low mass bosonic particles
which become trapped within the string core. This boson gas exerts a pressure
which tends to counteract the string tension, allowing a circular string loop
to find a finite equilibrium radius, provided that gas particles do not escape
the string core. However, high energy bosons do escape, and consequently the
loop shrinks and the temperature rises. Estimates indicate that the bosonic
stabilization mechanism is ineffective, and the loop is unstable against decay.


title: Finite size induces crossover temperature in growing spin chains

abstract:
  We introduce a growing one-dimensional quenched spin model that bases on
asymmetrical one-side Ising interactions in the presence of external field.
Numerical simulations and analytical calculations based on Markov chain theory
show that when the external field is smaller than the exchange coupling
constant $J$ there is a non-monotonous dependence of the mean magnetization on
the temperature in a finite system. The crossover temperature $T_c$
corresponding to the maximal magnetization decays with system size,
approximately as the inverse of the W Lambert function. The observed phenomenon
can be understood as an interplay between the thermal fluctuations and the
presence of the first cluster determined by initial conditions. The effect
exists also when spins are not quenched but fully thermalized after the
attachment to the chain. We conceive the model is suitable for a qualitative
description of online emotional discussions arranged in a chronological order,
where a spin in every node conveys emotional valence of a subsequent post.


title: Double Antisymmetry and the Rotation-Reversal Space Groups

abstract:
  Rotation-reversal symmetry was recently introduced to generalize the symmetry
classification of rigid static rotations in crystals such as tilted octahedra
in perovskite structures and tilted tetrahedral in silica structures. This
operation has important implications for crystallographic group theory, namely
that new symmetry groups are necessary to properly describe observations of
rotation-reversal symmetry in crystals. When both rotation-reversal symmetry
and time-reversal symmetry are considered in conjunction with space group
symmetry, it is found that there are 17,803 types of symmetry, called double
antisymmetry, which a crystal structure can exhibit. These symmetry groups have
the potential to advance understanding of polyhedral rotations in crystals, the
magnetic structure of crystals, and the coupling thereof. The full listing of
the double antisymmetry space groups can be found in the supplemental materials
of the present work and online at our website:
http://sites.psu.edu/gopalan/research/symmetry/


title: Constraints on Neutrino Mass from Sunyaev--Zeldovich Cluster Surveys

abstract:
  The presence of massive neutrinos has a characteristic impact on the growth
of large scale structures such as galaxy clusters. We forecast on the
capability of the number count and power spectrum measured from the ongoing and
future Sunyaev-Zeldovich (SZ) cluster surveys, combined with cosmic microwave
background (CMB) observation to constrain the total neutrino mass $\mnu$ in a
flat $\Lambda$CDM cosmology. We adopt self-calibration for the mass-observable
scaling relation, and evaluate constraints for the South Pole Telescope normal
and with polarization (SPT, SPTPol), Planck, and Atacama Cosmology Telescope
Polarization (ACTPol) surveys. We find that a sample of $\approx1000$ clusters
obtained from the Planck cluster survey plus extra information from CMB lensing
extraction could tighten the current upper bound on the sum of neutrino masses
to $\sigma_{\mnu}=0.17$ eV at 68% C.L. Our analysis shows that cluster number
counts and power spectrum provide complementary constraints and as a result
they help reducing the error bars on $\mnu$ by a factor of 4-8 when both probes
are combined. We also show that the main strength of cluster measurements in
constraining $\mnu$ is when good control of cluster systematics is available.
When applying a weak prior on the mass-observable relations, which can be at
reach in the upcoming cluster surveys, we obtain $\sigma_{\mnu}=0.48$ eV using
cluster only probes and, more interestingly, $\sigma_{\mnu}=0.08$ eV using
cluster + CMB which corresponds to a $S/N\approx4$ detection for $\mnu\ge0.3$
eV. We analyze and discuss the degeneracies of $\mnu$ with other parameters and
investigate the sensitivity of neutrino mass constraints with various surveys
specifications.


title: Logarithmic Conformal Field Theory: a Lattice Approach

abstract:
  Logarithmic Conformal Field Theories (LCFT) play a key role, for instance, in
the description of critical geometrical problems (percolation, self avoiding
walks, etc.), or of critical points in several classes of disordered systems
(transition between plateaus in the integer and spin quantum Hall effects).
Much progress in their understanding has been obtained by studying algebraic
features of their lattice regularizations. For reasons which are not entirely
understood, the non semi-simple associative algebras underlying these lattice
models - such as the Temperley-Lieb algebra or the blob algebra - indeed
exhibit, in finite size, properties that are in full correspondence with those
of their continuum limits. This applies to the structure of indecomposable
modules, but also to fusion rules, and provides an `experimental' way of
measuring couplings, such as the `number b' quantifying the logarithmic
coupling of the stress energy tensor with its partner. Most results obtained so
far have concerned boundary LCFTs, and the associated indecomposability in the
chiral sector. While the bulk case is considerably more involved (mixing in
general left and right moving sectors), progress has also been made in this
direction recently, uncovering fascinating structures. This article provides a
short general review of our work in this area.

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


title: On Artin algebras arising from Morita contexts

abstract:
  We study Morita rings $\Lambda_{(\phi,\psi)}=\bigl({smallmatrix} A
&_AN_B_BM_A & B {smallmatrix}\bigr)$ in the context of Artin algebras from
various perspectives. First we study covariant finite, contravariant finite,
and functorially finite subcategories of the module category of a Morita ring
when the bimodule homomorphisms $\phi$ and $\psi$ are zero. Further we give
bounds for the global dimension of a Morita ring $\Lambda_{(0,0)}$, regarded as
an Artin algebra, in terms of the global dimensions of $A$ and $B$ in the case
when both $\phi$ and $\psi$ are zero. We illustrate our bounds with some
examples. Finally we investigate when a Morita ring is a Gorenstein Artin
algebra and then we determine all the Gorenstein-projective modules over the
Morita ring with $A=N=M=B=\Lambda$, where $\Lambda$ is an Artin algebra.