title: Fractures in complex fluids: the case of transient networks

abstract:
  We present a comprehensive review of the current state of fracture phenomena
in transient networks, a wide class of viscoelastic fluids. We will first
define what is a fracture in a complex fluid, and recall the main structural
and rheological properties of transient networks. Secondly, we review
experimental reports on fractures of transient networks in several
configurations: shear-induced fractures, fractures in Hele-Shaw cells and
fracture in extensional geometries (filament stretching rheometry and pendant
drop experiments), including fracture propagation. The tentative extension of
the concepts of brittleness and ductility to the fracture mechanisms in
transient networks is also discussed. Finally, the different and apparently
contradictory theoretical approaches developed to interpret fracture nucleation
will be addressed and confronted to experimental results. Rationalized criteria
to discriminate the relevance of these different models will be proposed.


title: Maximal harmonic group actions on finite graphs

abstract:
  This paper studies groups of maximal size acting harmonically on a finite
graph. Our main result states that these maximal graph groups are exactly the
finite quotients of the modular group $\Gamma=\left<x,y \ | \ x^2=y^3=1\right>$
of size at least 6. This characterization may be viewed as a discrete analogue
of the description of Hurwitz groups as finite quotients of the
$(2,3,7)$-triangle group in the context of holomorphic group actions on Riemann
surfaces. In fact, as an immediate consequence of our result, every Hurwitz
group is a maximal graph group, and the final section of the paper establishes
a direct connection between maximal graphs and Hurwitz surfaces via the theory
of combinatorial maps.


title: D5-brane boundary reflection factors

abstract:
  We compute the strong coupling limit of the boundary reflection factor for
excitations on open strings attached to various kinds of D5-branes that probe
AdS5 x S5. We study the crossing equation, which constrains the boundary
reflection factor, and propose that some solutions will give the boundary
reflection factors for all values of the coupling. Our proposal passes various
checks in the strong coupling limit by comparison with diverse explicit string
theory computations. In some of the cases we consider, the D5-branes correspond
to 1/2 BPS Wilson loops in the k-th rank antisymmetric representation of the
dual field theory. In the other cases they correspond in the dual field theory
to the addition of a fundamental hypermultiplet in a defect.


title: BLM realization for Frobenius--Lusztig Kernels of type A

abstract:
  The infinitesimal quantum $\frak{gl}_n$ was realized in \cite[\S 6]{BLM}. We
will realize Frobenius--Lusztig Kernels of type $A$ in this paper.


title: Superdeformed oblate superheavy nuclei in the self-consistent approach

abstract:
  The HFB self-consistent method has been applied to study the properties of
several neutron deficient superheavy nuclei with Z=120-124, N=160-168. Their
distinctive feature is the existence of minima of the total HFB energy for
strongly deformed, oblate shapes. The self-consistent results agree quite
remarkably with those currently obtained by using microscopic-macroscopic
method.


title:
Structure of a model salt bridge in solution investigated with 2D-IR
  spectroscopy

abstract:
  Salt bridges are known to be important for the stability of protein
conformation, but up to now it has been difficult to study their geometry in
solution. Here we characterize the spatial structure of a model salt bridge
between guanidinium (Gdm+) and acetate (Ac-) using two-dimensional vibrational
(2D-IR) spectroscopy. We find that as a result of salt bridging the infrared
response of Gdm+ and Ac- change significantly, and in the 2D-IR spectrum, salt
bridging of the molecules appears as cross peaks. From the 2D-IR spectrum we
determine the relative orientation of the transition-dipole moments of the
vibrational modes involved in the salt bridge, as well as the coupling between
them. In this manner we reconstruct the geometry of the solvated salt bridge.


title:
Constraining a fourth generation of quarks: non-perturbative Higgs boson
  mass bounds

abstract:
  We present a non-perturbative determination of the upper and lower Higgs
boson mass bounds with a heavy fourth generation of quarks from numerical
lattice computations in a chirally symmetric Higgs-Yukawa model. We find that
the upper bound only moderately rises with the quark mass while the lower bound
increases significantly, providing additional constraints on the existence of a
straight-forward fourth quark generation. We examine the stability of the lower
bound under the addition of a higher dimensional operator to the scalar field
potential using perturbation theory, demonstrating that it is not significantly
altered for small values of the coupling of this operator. For a Higgs boson
mass of $\sim125\mathrm{GeV}$ we find that the maximum value of the fourth
generation quark mass is $\sim300\mathrm{GeV}$, which is already in conflict
with bounds from direct searches.


title:
Intensity fluctuations in bimodal micropillar lasers enhanced by
  quantum-dot gain competition

abstract:
  We investigate correlations between orthogonally polarized cavity modes of a
bimodal micropillar laser with a single layer of self-assembled quantum dots in
the active region. While one emission mode of the microlaser demonstrates a
characteristic s-shaped input-output curve, the output intensity of the second
mode saturates and even decreases with increasing injection current above
threshold. Measuring the photon auto-correlation function g^{(2)}(\tau) of the
light emission confirms the onset of lasing in the first mode with g^{(2)}(0)
approaching unity above threshold. In contrast, strong photon bunching
associated with super-thermal values of g^{(2)}(0) is detected for the other
mode for currents above threshold. This behavior is attributed to gain
competition of the two modes induced by the common gain material, which is
confirmed by photon crosscorrelation measurements revealing a clear
anti-correlation between emission events of the two modes. The experimental
studies are in excellent qualitative agreement with theoretical studies based
on a microscopic semiconductor theory, which we extend to the case of two modes
interacting with the common gain medium. Moreover, we treat the problem by an
extended birth-death model for two interacting modes, which reveals, that the
photon probability distribution of each mode has a double peak structure,
indicating switching behavior of the modes for the pump rates around threshold.


title:
Algorithm of Amorphous Carbonaceous Nanomaterial Structure
  Identification with a Joint X-Ray and Neutron Diffraction Data Analysis

abstract:
  An algorithm is developed for structure identification of amorphous
carbonaceous nanomaterials with a joint x-ray and neutron diffraction data
analysis, using the data on the chemical composition of the sample from other
diagnostics. The algorithm is an extension of one formerly developed for the
x-ray diffraction diagnostics of similar nanomaterials ([1] Chem. Phys. Lett.,
506, 265-268 (2011)). The algorithm is tested on the example of processing the
computed data for a sample which models a fragment of hydrocarbon films
analyzed in [1]. The algorithm is of interest for structure diagnostics of
materials with comparable atomic fractions of carbon and hydrogen.


title: Generating functions from the viewpoint of Rota-Baxter algebras

abstract:
  We study generating functions in the context of Rota-Baxter algebras. We show
that exponential generating functions can be naturally viewed in a very special
case of complete free commutative Rota-Baxter algebras. This allows us to use
free Rota-Baxter algebras to give a broad class of algebraic structures in
which generalizations of generating functions can be studied. We generalize the
product formula and composition formula for exponential power series. We also
give generating functions both for known number families such as Stirling
numbers of the second kind and partition numbers, and for new number families
such as those from not necessarily disjoint partitions and partitions of
multisets.


title: Ultrarelativistic Transport Coefficients in Two Dimensions

abstract:
  We compute the shear and bulk viscosities, as well as the thermal
conductivity of an ultrarelativistic fluid obeying the relativistic Boltzmann
equation in 2+1 space-time dimensions. The relativistic Boltzmann equation is
taken in the single relaxation time approximation, based on two approaches, the
first, due to Marle and using the Eckart decomposition, and the second,
proposed by Anderson and Witting and using the Landau-Lifshitz decomposition.
In both cases, the local equilibrium is given by a Maxwell-Juettner
distribution. It is shown that, apart from slightly different numerical
prefactors, the two models lead to a different dependence of the transport
coefficients on the fluid temperature, quadratic and linear, for the case of
Marle and Anderson-Witting, respectively. However, by modifying the Marle model
according to the prescriptions given in Ref.[1], it is found that the
temperature dependence becomes the same as for the Anderson-Witting model.


title: Universal Subspaces for Local Unitary Groups of Fermionic Systems

abstract:
  Let $\mathcal{V}=\wedge^N V$ be the $N$-fermion Hilbert space with
$M$-dimensional single particle space $V$ and $2N\le M$. We refer to the
unitary group $G$ of $V$ as the local unitary (LU) group. We fix an orthonormal
(o.n.) basis $\ket{v_1},...,\ket{v_M}$ of $V$. Then the Slater determinants
$e_{i_1,...,i_N}:= \ket{v_{i_1}\we v_{i_2}\we...\we v_{i_N}}$ with
$i_1<...<i_N$ form an o.n. basis of $\cV$. Let $\cS\subseteq\cV$ be the
subspace spanned by all $e_{i_1,...,i_N}$ such that the set $\{i_1,...,i_N\}$
contains no pair $\{2k-1,2k\}$, $k$ an integer. We say that the
$\ket{\psi}\in\cS$ are single occupancy states (with respect to the basis
$\ket{v_1},...,\ket{v_M}$). We prove that for N=3 the subspace $\cS$ is
universal, i.e., each $G$-orbit in $\cV$ meets $\cS$, and that this is false
for N>3. If $M$ is even, the well known BCS states are not LU-equivalent to any
single occupancy state. Our main result is that for N=3 and $M$ even there is a
universal subspace $\cW\subseteq\cS$ spanned by $M(M-1)(M-5)/6$ states
$e_{i_1,...,i_N}$. Moreover the number $M(M-1)(M-5)/6$ is minimal.


title:
Metabolic and Chaperone Gene Loss Marks the Origin of Animals: Evidence
  for Hsp104 and Hsp78 Sharing Mitochondrial Clients

abstract:
  The evolution of animals involved acquisition of an emergent gene repertoire
for gastrulation. Whether loss of genes also co-evolved with this developmental
reprogramming has not yet been addressed. Here, we identify twenty-four genetic
functions that are retained in fungi and choanoflagellates but undetectable in
animals. These lost genes encode: (i) sixteen distinct biosynthetic functions;
(ii) the two ancestral eukaryotic ClpB disaggregases, Hsp78 and Hsp104, which
function in the mitochondria and cytosol, respectively; and (iii) six other
assorted functions. We present computational and experimental data that are
consistent with a joint function for the differentially localized ClpB
disaggregases, and with the possibility of a shared client/chaperone
relationship between the mitochondrial Fe/S homoaconitase encoded by the lost
LYS4 gene and the two ClpBs. Our analyses lead to the hypothesis that the
evolution of gastrulation-based multicellularity in animals led to efficient
extraction of nutrients from dietary sources, loss of natural selection for
maintenance of energetically expensive biosynthetic pathways, and subsequent
loss of their attendant ClpB chaperones.


title: Relativistic Lattice Boltzmann Model with Improved Dissipation

abstract:
  We develop a relativistic lattice Boltzmann (LB) model, providing a more
accurate description of dissipative phenomena in relativistic hydrodynamics
than previously available with existing LB schemes. The procedure applies to
the ultra-relativistic regime, in which the kinetic energy (temperature) far
exceeds the rest mass energy, although the extension to massive particles
and/or low temperatures is conceptually straightforward. In order to improve
the description of dissipative effects, the Maxwell-Juettner distribution is
expanded in a basis of orthonormal polynomials, so as to correctly recover the
third order moment of the distribution function. In addition, a time dilatation
is also applied, in order to preserve the compatibility of the scheme with a
cartesian cubic lattice. To the purpose of comparing the present LB model with
previous ones, the time transformation is also applied to a lattice model which
recovers terms up to second order, namely up to energy-momentum tensor. The
approach is validated through quantitative comparison between the second and
third order schemes with BAMPS (the solution of the full relativistic Boltzmann
equation), for moderately high viscosity and velocities, and also with previous
LB models in the literature. Excellent agreement with BAMPS and more accurate
results than previous relativistic lattice Boltzmann models are reported.

categories: physics.comp-ph cond-mat.stat-mech hep-th physics.flu-dyn physics.plasm-ph


title:
A search for HI 21cm absorption towards a radio-selected quasar sample
  II: a new low spin temperature DLA at high redshift

abstract:
  We report results from a deep search for redshifted HI 21cm absorption from
eight damped Lyman-$\alpha$ absorbers (DLAs) detected in our earlier optical
survey for DLAs towards radio-loud quasars. HI 21cm absorption was detected
from the $z = 2.192$ DLA towards TXS2039+187, only the sixth case of such a
detection at $z > 2$, while upper limits on the HI 21cm optical depth were
obtained in six other DLAs at $z > 2$. Our detection of HI 21cm absorption in
the eighth system, at $z = 2.289$ towards TXS0311+430, has been reported
earlier. We also present high spatial resolution images of the background
quasars at frequencies close to the redshifted HI 21cm line frequency, allowing
us to estimate the covering factor of each DLA, and then determine its spin
temperature $T_s$. For three non-detections of HI 21cm absorption, we obtain
strong lower limits on the spin temperature, $T_s \gtrsim 790$ K, similar to
the bulk of the high-$z$ DLA population; three other DLAs yield weak lower
limits, $T_s > 140-400$ K. However, for the two DLAs with detections of HI 21cm
absorption, the derived spin temperatures are both low $T_s = (160 \pm 35)
\times (f/0.35)$ K for the $z = 2.192$ DLA towards TXS2039+187 and $T_s = (72
\pm 18) \times (f/0.52)$ K for the $z = 2.289$ DLA towards TXS0311+430. These
are the first two DLAs at $z > 1$ with $T_s$ values comparable to those
obtained in local spiral galaxies. Based on the observed correlations between
spin temperature and metallicity and velocity spread and metallicity in DLAs,
we suggest that the hosts of the two absorbers are likely to be massive,
high-metallicity galaxies.


title: Inverse problem of group analysis for autonomous differential systems

abstract:
  Full set of autonomous completely solvable differential systems of equations
in total differentials is built by basis of infinitesimal operators, universal
invariant, and structure constants of admited multiparametric Lie group
(abelian and non-abelian).


title: Travelling Wave Magnetic Resonance Imaging at 3 Tesla

abstract:
  Waveguides have been successfully used to generate magnetic resonance images
at 7 T with whole-body systems. The bore limits the magnetic resonance signal
transmitted because its specific cut-off frequency is greater than the majority
of resonant frequencies. This restriction can be overcome by using a
parallel-plate waveguide whose cut-off frequency is zero for the transversal
electric modes and it can propagate any frequency. To investigate the potential
benefits for whole-body imaging at 3 T, we compare numerical simulations at 1.5
T, 3 T, 7 T, and 9 T via the propagation of the parallel-plate waveguide
principal mode filled with a cylindrical phantom and two surface coils. B1
mapping was computed to investigate the feasibility of this approach at 3T. The
point spread function method was used to measure the imager performance for the
traveling-wave magnetic resonance imaging experiment. Human leg images were
acquired to experimentally validate this approach. The principal mode shows
very little field magnitude variations along the propagation direction at 3 T
when compared to other higher resonant frequencies. The B1 mapping showed that
it is possible to conduct experiments using the traveling-wave approach at 128
MHz. The point spread function results showed a good scanner performance for
these type of experiments. Leg images were obtained with the whole-body
birdcage coil and the waveguide with two circular coils for comparison
purposes. The simulated and in vivo traveling-wave results correspond very well
for both magnetic field and specific absorption rate. A pretty similar
performance was observed for the traveling-wave approach and the conventional
one. We have demonstrated the feasibility of traveling-wave magnetic resonance
imaging at 3T for whole-body magnetic resonance systems, using a parallel-plate
waveguide with standard pulse sequences and only one coil array.


title:
Development of the Magnetic Excitations of Charge-Stripe Ordered
  La(2-x)Sr(x)NiO(4) on Doping Towards Checkerboard Charge Order

abstract:
  The magnetic excitation spectrums of charge stripe ordered La(2-x)Sr(x)NiO(4)
x = 0.45 and x = 0.4 were studied by inelastic neutron scattering. We found the
magnetic excitation spectrum of x = 0.45 from the ordered Ni^2+ S = 1 spins to
match that of checkerboard charge ordered La(1.5)Sr(0.5)NiO(4). The distinctive
asymmetry in the magnetic excitations above 40 meV was observed for both doping
levels, but an additional ferromagnetic mode was observed in x = 0.45 and not
in the x = 0.4. We discuss the origin of crossover in the excitation spectrum
between x = 0.45 and x = 0.4 with respect to discommensurations in the charge
stripe structure.


title: Hydrodynamic Model for Conductivity in Graphene

abstract:
  Based on the recently developed picture of an electronic ideal relativistic
fluid at the Dirac point, we present an analytical model for the conductivity
in graphene that is able to describe the linear dependence on the carrier
density and the existence of a minimum conductivity. The model treats
impurities as submerged rigid obstacles, forming a disordered medium through
which graphene electrons flow, in close analogy with classical fluid dynamics.
To describe the minimum conductivity, we take into account the additional
carrier density induced by the impurities in the sample. The model, which
predicts the conductivity as a function of the impurity fraction of the sample,
is supported by extensive simulations for different values of ${\cal E}$, the
dimensionless strength of the electric field, and provides excellent agreement
with experimental data.

categories: cond-mat.mes-hall cond-mat.dis-nn cond-mat.mtrl-sci physics.flu-dyn


title:
Comment on "Black Holes are Neither Particle Accelerators Nor Dark
  Matter Probes"

abstract:
  The Banados-Silk-West effect consists in the possibility to get infinite
energy in the centre of mass frame of two particles colliding near the black
hole horizon. According to S. T. McWilliams, Phys. Rev. Lett. 110 (2013)
011102, the energy at infinity of the outcome vanishes because of infinite
redshift when the point of collision approaches the horizon. I show that this
is not so.


title: Inhomogeneous condensates in the parity doublet model

abstract:
  Within the parity doublet model coupled to the linear sigma model including
vector mesons it is possible to describe vacuum properties of the low energy
mesons and to achieve nuclear saturation at nonzero density. Motivated by
recent studies we investigate the emergence of inhomogeneous condensation in
the parity doublet model. As a first step the chiral density wave (CDW) is con-
sidered, which allows for a straightforward investigation of inhomogeneous
condensation. As a result it is still possible to have a homogeneous ground
state of nuclear matter, but at larger baryon chemical potential the CDW is
favored with respect to the homogeneous phase.


title:
Single spin-torque vortex oscillator using combined bottom-up approach
  and e-beam lithography

abstract:
  A combined bottom-up assembly of electrodeposited nanowires and electron beam
lithography technique has been developed to investigate the spin transfer
torque and microwave emission on specially designed nanowires containing a
single Co/Cu/Co pseudo spin valve. Microwave signals have been obtained even at
zero magnetic field. Interestingly, high frequency vs. magnetic field
tunability was demonstrated, in the range 0.4 - 2 MHz/Oe, depending on the
orientation of the applied magnetic field relative to the magnetic layers of
the pseudo spin valve. The frequency values and the emitted signal frequency as
a function of the external magnetic field are in good quantitative agreement
with the analytical vortex model as well as with micromagnetic simulations.


title:
Pressure exerted by a grafted polymer on the limiting line of a
  semi-infinite square lattice

abstract:
  Using exact enumerations of self-avoiding walks (SAWs) we compute the
inhomogeneous pressure exerted by a two-dimensional end-grafted polymer on the
grafting line which limits a semi-infinite square lattice. The results for SAWs
show that the asymptotic decay of the pressure as a function of the distance to
the grafting point follows a power-law with an exponent similar to that of
gaussian chains and is, in this sense, independent of excluded volume effects.


title:
A cortical-inspired geometry for contour perception and motion
  integration

abstract:
  In this paper we develop a geometrical model of functional architecture for
the processing of spatio-temporal visual stimuli. The model arises from the
properties of the receptive field linear dynamics of orientation and
speed-selective cells in the visual cortex, that can be embedded in the
definition of a geometry where the connectivity between points is driven by the
contact structure of a 5D manifold. Then, we compute the stochastic kernels
that are the approximations of two Fokker Planck operators associated to the
geometry, and implement them as facilitation patterns within a neural
population activity model, in order to reproduce some psychophysiological
findings about the perception of contours in motion and trajectories of points
found in the literature.


title: Strongly correlated dynamics in multichannel quantum RC circuits

abstract:
  We examine dissipation effects in a multichannel quantum RC circuit,
comprising a cavity or single-electron box capacitively coupled to a gate and
connected to a reservoir lead via several conducting channels. Depending on the
engineering details of the quantum RC circuit, the number of channels
contributing to transport vary, as do the form of the interchannel couplings.
For low-frequency AC transport, the charge-relaxation resistance ($R_{q}$) is a
nontrivial function of the parameters of the system. However, in the vicinity
of the charge degeneracy points and for weak tunneling, we find as a result of
cross-mode mixing or channel asymmetry that $R_q$ becomes universal for a
metallic cavity at low temperatures, and equals the unit of quantum resistance.
To prove this universality we map the system to an effective one-channel Kondo
model, and construct an analogy with the Coulomb gas. Next, we probe the
opposite regime of near-perfect transmission using a bosonization approach.
Focussing on the two-channel case, we study the effect of backscattering at the
lead-dot interface, more specifically, the role of an asymmetry in the
backscattering amplitudes, and make a connection with the weak tunneling regime
near the charge degeneracy points.


title:
Long-term photometry of three active red giants in close binary systems:
  V2253 Oph, IT Com and IS Vir

abstract:
  We present and analyze long-term optical photometric measurements of the
three active stars V2253 Oph, IT Com and IS Vir. All three systems are
single-lined spectroscopic binaries with an early K giant as primary component
but in different stages of orbital-rotational synchronization. Our photometry
is supplemented by 2MASS and WISE near-IR and mid-IR magnitudes and then used
to obtain more accurate effective temperatures and extinctions. For V2253 Oph
and IT Com, we found their spectral energy distributions consistent with pure
photospheric emission. For IS Vir, we detect a marginal mid-IR excess which
hints towards a dust disk. The orbital and rotational planes of IT Com appear
to be coplanar, contrary to previous findings in the literature. We apply a
multiple frequency analysis technique to determine photometric periods, and
possibly changes of periods, ranging from days to decades. New rotational
periods of 21.55+-0.03d, 65.1+-0.3d, and 23.50+-0.04d were determined for V2253
Oph, IT Com, and IS Vir, respectively. Splitting of these periods led to
tentative detections of differential surface rotations of delta P/P ~0.02 for
V2253 Oph and 0.07 for IT Com. Using a time-frequency technique based on
short-term Fourier transforms we present evidence of cyclic light variations of
length ~10yrs for V2253 Oph and 5-6yrs for IS Vir. A single flip-flop event has
been observed for IT Com of duration 2-3yrs. Its exchange of the dominant
active longitude had happened close to a time of periastron passage, suggesting
some response of the magnetic activity from the orbital dynamics. The 21.55-d
rotational modulation of V2253 Oph showed phase coherence also with the orbital
period, which is 15 times longer than the rotational period, thus also
indicating a tidal feedback with the stellar magnetic activity.


title:
Local exclusion and Lieb-Thirring inequalities for intermediate and
  fractional statistics

abstract:
  In one and two spatial dimensions there is a logical possibility for
identical quantum particles different from bosons and fermions, obeying
intermediate or fractional (anyon) statistics. We consider applications of a
recent Lieb-Thirring inequality for anyons in two dimensions, and derive new
Lieb-Thirring inequalities for intermediate statistics in one dimension with
implications for models of Lieb-Liniger and Calogero-Sutherland type. These
inequalities follow from a local form of the exclusion principle valid for such
generalized exchange statistics.

categories: math-ph cond-mat.quant-gas math.MP math.SP


title: Lorentz completion of effective string action

abstract:
  In the presence of a confining flux tube between a pair of sources the vacuum
is no longer Poincare' invariant. This symmetry is nonlinearly realized in the
effective string action. A general method for finding a large class of Lorentz
invariant contributions to the action is described. The relationship between
this symmetry and diffeomorphism invariance is further investigated.


title: Signals embedded in the radial velocity noise

abstract:
  Bayesian data analysis techniques, together with suitable statistical models,
can be used to obtain much more information from noisy data than the
traditional frequentist methods. For instance, when searching for periodic
signals in noisy data, the Bayesian techniques can be used to define exact
detection criteria for low-amplitude signals - the most interesting signals
that might correspond to habitable planets. We present an overview of Bayesian
techniques and present detailed analyses of the HARPS-TERRA velocities of HD
40307, a nearby star observed to host a candidate habitable planet, to
demonstrate in practice the applicability of Bayes' rule to astronomical data.


title: Modulated curvaton decay

abstract:
  We study primordial density perturbations generated by the late decay of a
curvaton field whose decay rate may be modulated by the local value of another
isocurvature field, analogous to models of modulated reheating at the end of
inflation. We calculate the primordial density perturbation and its local-type
non-Gaussianity using the sudden-decay approximation for the curvaton field,
recovering standard curvaton and modulated reheating results as limiting cases.
We verify the Suyama-Yamaguchi inequality between bispectrum and trispectrum
parameters for the primordial density field generated by multiple field
fluctuations, and find conditions for the bound to be saturated.


title:
Resonant Bound-Free Contributions to Thomson Scattering of X-rays by
  Warm Dense Matter

abstract:
  Recent calculations [Nilsen et al. arXiv:1212.5972] predict that
contributions to the scattered photon spectrum from 3s and 3p bound states in
chromium (Z=24) at metallic density and T=12 eV resonate below the respective
bound-state thresholds. These resonances are shown to be closely related to
continuum lowering, where 3d bound states in the free atom dissolve into a
resonant l=2 partial wave in the continuum. The resulting d-state resonance
dominates contributions to the bound-free dynamic structure function, leading
to the predicted resonances in the scattered X-ray spectrum. Similar resonant
features are shown to occur in all elements in the periodic table between Ca
and Mn (20 <= Z <= 25).


title:
Non-simplicial decompositions of Betti diagrams of complete
  intersections

abstract:
  We investigate decompositions of Betti diagrams over a polynomial ring within
the framework of Boij--Soederberg theory. That is, given a Betti diagram, we
decompose it into pure diagrams. Relaxing the requirement that the degree
sequences in such pure diagrams be totally ordered, we are able to define a
multiplication law for Betti diagrams that respects the decomposition and
allows us to write a simple expression the decomposition of the Betti diagram
of any complete intersection in terms of the degrees of its minimal generators.
In the more traditional sense, the decomposition of complete intersections of
codimension at most 3 are also computed as given by the totally ordered
decomposition algorithm obtained from (Eisenbud-Schreyer, 2009). In higher
codimension, obstructions arise that inspire our work on an alternative
algorithm.


title: Entanglement witnesses for a class of bipartite states of n x n qubits

abstract:
  We characterize the positive maps detecting the entangled bipartite states of
n x n qubits that are diagonal with respect to the orthonormal basis
constructed by tensor products of Pauli matrices acting on the totally
symmetric state. We then discuss the case n=2 for a class of states completely
determined by the geometric patterns of subsets of a 16 point lattice.


title: Calculating the Fundamental Group of the Circle in Homotopy Type Theory

abstract:
  Recent work on homotopy type theory exploits an exciting new correspondence
between Martin-Lof's dependent type theory and the mathematical disciplines of
category theory and homotopy theory. The category theory and homotopy theory
suggest new principles to add to type theory, and type theory can be used in
novel ways to formalize these areas of mathematics. In this paper, we formalize
a basic result in algebraic topology, that the fundamental group of the circle
is the integers. Though simple, this example is interesting for several
reasons: it illustrates the new principles in homotopy type theory; it mixes
ideas from traditional homotopy-theoretic proofs of the result with
type-theoretic inductive reasoning; and it provides a context for understanding
an existing puzzle in type theory---that a universe (type of types) is
necessary to prove that the constructors of inductive types are disjoint and
injective.


title:
Pure annihilation type $ D\to PP(V)$ decays in the perturbative QCD
  approach

abstract:
  The annihilation type diagrams are difficult to calculate in any kind of
models or method. Encouraged by the the successful calculation of pure
annihilation type B decays in the perturbative QCD factorization approach, we
calculate the pure annihilation type $D\to PP(V)$ decays in the perturbative
QCD approach based on the $k_T$ factorization. Although the expansion parameter
$1/m_D$ is not very small, our leading order numerical results agree with the
existing experiment data for most channels. We expect the more accurate
observation from experiments, which can help us learn about the dynamics of $D$
meson weak decays.


title:
Constraints on the R-parity violating couplings using the newest
  measurement of the decay $B_s^0 \rightarrow \mu^+ \mu^-$

abstract:
  Recently, the LHCb collaboration reported the first evidence for the decay
$B_s^0 \rightarrow \mu^+ \mu^-$. A branching ratio of $\mathcal{B}(B_s^0
\rightarrow \mu^+ \mu^-) = (3.2^{+1.5}_{-1.2}) \times 10^{-9}$ is given. Using
the newest data, and together with the most precise predictions of the Standard
Model contributions to the decay, we derive the constraints on the combinations
of the R-parity violating parameters. Our results are several orders of
magnitudes stronger than the constraints in the previous literature. We also
update the constraints on the relevant parameters using the upper limit of
$\mathcal{B}(B_d^0 \rightarrow \mu^+ \mu^-)$.


title:
The structure of the thermally bistable and turbulent atomic gas in the
  local interstellar medium

abstract:
  This paper is a numerical study of the condensation of the warm neutral
medium (WNM) into cold neutral medium (CNM) structures under the effect of
turbulence and thermal instability. Using low resolution simulations we
explored the impact of the WNM initial density and properties of the turbulence
(stirring in Fourier with a varying mix of solenoidal and compressive modes) on
the cold gas formation. Two sets of initial conditions which match the
observations were selected to produce high resolution simulations (1024^3)
allowing to study in details the properties of the produced dense structures.
For typical values of the density, pressure and velocity dispersion of the WNM
in the solar neighborhood, the turbulent motions of the HI can not provoque the
phase transition from WNM to CNM, whatever their amplitude and their
distribution in solenoidal and compressive modes. On the other hand we show
that a quasi-isothermal increase in WNM density of a factor of 2 to 4 is enough
to induce the phase transition, leading to the transition of about 40 percent
of the gas to the cold phase within 1 Myr. Given the observed properties of the
HI in the local ISM, the WNM and individual CNM structures in the local ISM are
sub or transsonic and their dynamics are tightly interwoven. The velocity field
bears the evidence of subsonic turbulence with a 2D power spectrum following
the Kolmogorov law as P(k) \sim k^{-8/3} while the density is highly contrasted
with a singificantly shallower power spectrum, reminiscent of what is observed
in the cold ISM. Supra-thermal line width observed for CNM might be the result
of relative velocity between cold structures. Finally, the cold structures
denser than 5 cm^{-3} reproduce well the laws M \sim L^{2.25-2.28} and sigma(v)
\sim 0.5-0.8L^{1/3} generally observed in molecular clouds.


title: Hermite-Hadamard type inequalities via preinvexity and prequasiinvexity

abstract:
  In this paper, we obtain some Hermite-Hadamard type inequalities for
functions whose third derivatives in absolute value are preinvex and
prequasiinvex.


title: Matrix elements of four-quark operators and \Delta L=2 hyperon decays

abstract:
  The study of neutrinoless double beta decays of nuclei and hyperons require
the calculation of hadronic matrix elements of local four-quark operators that
change the total charge by two units \Delta Q=2 . Using a low energy effective
Lagrangian that induces these transitions, we compute these hadronic matrix
elements in the framework of the MIT bag model. As an illustrative example we
evaluate the amplitude and transition rate of \Sigma- -> p e- e-, a decay
process that violates lepton number by two units (\Delta L=2). The relevant
matrix element is evaluated without assuming the usual factorization
approximation of the four-quark operators and the results obtained in both
approaches are compared.


title:
Bulk and shear spectral functions in weakly and strongly coupled
  Yang-Mills theory

abstract:
  In this talk, we discuss a number of recent calculations aimed at determining
the spectral functions corresponding to various components of the energy
momentum tensor in high-temperature SU(N) Yang-Mills theory. The computations
reviewed include applications of both weak coupling and gauge/gravity
techniques, and thus enable one to access different limits of the quantities.
The motivation for the work is twofold: On one hand, the results are hoped to
aid the eventual nonperturbative extraction of the bulk and shear viscosities
from lattice data, while on the other hand they also enable an immediate
comparison of the lattice, perturbative and holographic predictions for certain
Euclidean correlators.


title:
Unified ab initio approach to bound and unbound states: no-core shell
  model with continuum and its application to 7He

abstract:
  We introduce a unified approach to nuclear bound and continuum states based
on the coupling of the no-core shell model (NCSM), a bound-state technique,
with the no-core shell model/resonating group method (NCSM/RGM), a nuclear
scattering technique. This new ab initio method, no-core shell model with
continuum (NCSMC), leads to convergence properties superior to either NCSM or
NCSM/RGM while providing a balanced approach to different classes of states. In
the NCSMC, the ansatz for the many-nucleon wave function includes: i) a
square-integrable A-nucleon component expanded in a complete harmonic
oscillator basis; ii) a binary-cluster component with asymptotic boundary
conditions that can properly describe weakly-bound states, resonances and
scattering; and, in principle, iii) a three-cluster component suitable for the
description of, e.g., Borromean halo nuclei and reactions with final three-body
states. The Schroedinger equation is transformed into a system of
coupled-channel integral-differential equations that we solve using a modified
microscopic R-matrix formalism within a Lagrange mesh basis. We demonstrate the
usefulness of the approach by investigating the unbound 7He nucleus.


title: Eigenstructure of Maximum Likelihood from Counts Data

abstract:
  The MLE (Maximum Likelihood Estimate) for a multinomial model is proportional
to the data. We call such estimate an eigenestimate and the relationship of it
to the data as the eigenstructure. When the multinomial model is generalized to
deal with data arise from incomplete or censored categorical counts, we would
naturally look for this eigenstructure between MLE and data. The paper finds
the algebraic representation of the eigenstructure (put as Eqn (2.1)), with
which the intuition is visualized geometrically (Figures 2.2 and 4.3) and
elaborated in a theory (Section 4). The eigenestimate constructed from the
eigenstructure must be a stationary point of the likelihood, a result proved in
Theorem 4.42. On the bridge between the algebraic definition of Eqn (2.1) and
the Proof of Theorem 4.42, we have exploited an elementary inequality (Lemma
3.1) that governs the primitive cases, defined the thick objects of fragment
and slice which can be assembled like mechanical parts (Definition 4.1), proved
a few intermediary results that help build up the intuition (Section 4),
conjectured the universal existence of an eigenestimate (Conjecture 4.32),
established a criterion for boundary regularity (Criterion 4.37), and paved way
(the Trivial Slicing Algorithm (TSA)) for the derivation of the Weaver
algorithms (Section 5) that finds the eigenestimate by using it to reconstruct
the observed counts through the eigenstructure, the reconstruction is iterative
but derivative-free and matrix-inversion-free. As new addition to the current
body of algorithmic methods, the Weaver algorithms craftily tighten threads
that are weaved on a rectangular grid (Figure 2.3), and is one incarnation of
the TSA. Finally, we put our method in the context of some existing methods
(Section 6). Softwares are pseudocoded and put online. Visit
http://hku.hk/jdong/eigenstruct2013a.html for demonstrations and download.


title:
Exponential communication gap between weak and strong classical
  simulations of quantum communication

abstract:
  The most trivial way to simulate classically the communication of a quantum
state is to transmit the classical description of the quantum state itself.
However, this requires an infinite amount of classical communication if the
simulation is exact. A more intriguing and potentially less demanding strategy
would encode the full information about the quantum state into the probability
distribution of the communicated variables, so that this information is never
sent in each single shot. This kind of simulation is called weak, as opposed to
strong simulations, where the quantum state is communicated in individual
shots. In this paper, we introduce a bounded-error weak protocol for simulating
the communication of an arbitrary number of qubits and a subsequent two-outcome
measurement consisting of an arbitrary pure state projector and its complement.
This protocol requires an amount of classical communication independent of the
number of qubits and proportional to Delta^{-1}, where Delta is the error and a
free parameter of the protocol. Conversely, a bounded-error strong protocol
requires an amount of classical communication growing exponentially with the
number of qubits for a fixed error. Our result improves a previous protocol,
based on the Johnson-Lindenstrauss lemma, with communication cost scaling as
Delta^{-2} log Delta^{-1}.


title: 125 GeV Higgs Boson and the Type-II Seesaw Model

abstract:
  We study the vacuum stability and unitarity conditions for a 125 GeV Standard
Model (SM)-like Higgs boson mass in the type-II seesaw model. We find that, as
long as the seesaw scale is introduced below the SM vacuum instability bound,
there exists a large parameter space predicting a 125 GeV Higgs mass,
irrespective of the exact value of the seesaw scale, satisfying both stability
and unitarity conditions up to the Planck scale. We also study the model
predictions for the Higgs partial decay widths in the diphoton and Z+photon
channels with respect to their SM expectations and find that the decay rates
for these two processes are correlated. We further show that for any given
enhancement in the Higgs-to-diphoton rate over its SM expectation, there exists
an upper bound on the type-II seesaw scale, and hence, on the masses of the
associated doubly- and singly-charged Higgs bosons in the allowed parameter
space. For instance, if more than 10% enhancement persists in the
Higgs-to-diphoton channel, the upper limit on the type-II seesaw scale is about
450 GeV which is completely within the reach of the 14 TeV LHC. We believe this
to be an encouraging result for the experimental searches of the singly- and
doubly-charged Higgs bosons which, in combination with improved sensitivity in
the Higgs-to-diphoton and Higgs-to-Z+photon signal strengths, could probe the
entire allowed parameter space of the minimal type-II seesaw model, and
establish/eliminate it as a single viable extension of the SM.


title:
Detailed atmospheric abundance analysis of the optical counterpart of
  the IR source IRAS 16559-2957

abstract:
  We have undertaken a detailed abundance analysis of the optical counterpart
of the IR source IRAS16559-2957 with the aim of confirming its possible
post-AGB nature. The star shows solar metallicity and our investigation of a
large number of elements including CNO and 12C/13C suggests that this object
has experienced the first dredge-up and it is likely still at RGB stage.


title:
3D Geological Modeling and Visualization of Rock Masses Based on Google
  Earth: A Case Study

abstract:
  Google Earth (GE) has become a powerful tool for geological modeling and
visualization. An interesting and useful feature of GE, Google Street View, can
allow the GE users to view geological structure such as layers of rock masses
at a field site. In this paper, we introduce a practical solution for building
3D geological models for rock masses based on the data acquired by use with GE.
A real study case at Haut-Barr, France is presented to demonstrate our
solution. We first locate the position of Haut-Barr in GE, and then determine
the shape and scale of the rock masses in the study area, and thirdly acquire
the layout of layers of rock masses in the Google Street View, and finally
create the approximate 3D geological models by extruding and intersecting. The
generated 3D geological models can simply reflect the basic structure of the
rock masses at Haut-Barr, and can be used for visualizing the rock bodies
interactively.


title:
Fitting Methods for Baryon Acoustic Oscillations in the Lyman-{\alpha}
  Forest Fluctuations in BOSS Data Release 9

abstract:
  We describe fitting methods developed to analyze fluctuations in the
Lyman-{\alpha} forest and measure the parameters of baryon acoustic
oscillations (BAO). We apply our methods to BOSS Data Release 9. Our method is
based on models of the three-dimensional correlation function in physical
coordinate space, and includes the effects of redshift-space distortions,
anisotropic non-linear broadening, and broadband distortions. We allow for
independent scale factors along and perpendicular to the line of sight to
minimize the dependence on our assumed fiducial cosmology and to obtain
separate measurements of the BAO angular and relative velocity scales. Our
fitting software and the input files needed to reproduce our main BOSS Data
Release 9 results are publicly available.


title: A Geometric Descriptor for Cell-Division Detection

abstract:
  We describe a method for cell-division detection based on a geometric-driven
descriptor that can be represented as a 5-layers processing network, based
mainly on wavelet filtering and a test for mirror symmetry between pairs of
pixels. After the centroids of the descriptors are computed for a sequence of
frames, the two-steps piecewise constant function that best fits the sequence
of centroids determines the frame where the division occurs.


title:
Surface adsorption of lattice HP proteins: Thermodynamics and structural
  transitions using Wang-Landau sampling

abstract:
  Wang-Landau sampling has been applied to investigate the thermodynamics and
structural properties of a lattice hydrophobic-polar heteropolymer (the HP
protein model) interacting with an attractive substrate. For simplicity, we
consider a short HP sequence consisting of only 36 monomers interacting with a
substrate which attracts all monomers in the sequence. The conformational
"phase transitions" have been identified by a canonical analysis of the
specific heat and suitable structural observables. Three major "transitions",
namely, adsorption, hydrophobic core formation and "flattening" of adsorbed
structures, are observed. Depending on the surface attractive strength relative
to the intra-protein attraction among the H monomers, these processes take
place in different sequences upon cooling.

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


title:
Measurement of Baryon Acoustic Oscillations in the Lyman-alpha Forest
  Fluctuations in BOSS Data Release 9

abstract:
  We use the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9
(DR9) to detect and measure the position of the Baryonic Acoustic Oscillation
(BAO) feature in the three-dimensional correlation function in the Lyman-alpha
forest flux fluctuations at a redshift z=2.4. The feature is clearly detected
at significance between 3 and 5 sigma (depending on the broadband model and
method of error covariance matrix estimation) and is consistent with
predictions of the standard LCDM model. We assess the biases in our method,
stability of the error covariance matrix and possible systematic effects. We
fit the resulting correlation function with several models that decouple the
broadband and acoustic scale information. For an isotropic dilation factor, we
measure 100x(alpha_iso-1) = -1.6 ^{+2.0+4.3+7.4}_{-2.0-4.1-6.8} (stat.) +/- 1.0
(syst.) (multiple statistical errors denote 1,2 and 3 sigma confidence limits)
with respect to the acoustic scale in the fiducial cosmological model (flat
LCDM with Omega_m=0.27, h=0.7). When fitting separately for the radial and
transversal dilation factors we find marginalised constraints 100x(alpha_par-1)
= -1.3 ^{+3.5+7.6 +12.3}_{-3.3-6.7-10.2} (stat.) +/- 2.0 (syst.) and
100x(alpha_perp-1) = -2.2 ^{+7.4+17}_{-7.1-15} +/- 3.0 (syst.). The dilation
factor measurements are significantly correlated with cross-correlation
coefficient of ~ -0.55. Errors become significantly non-Gaussian for deviations
over 3 standard deviations from best fit value. Because of the data cuts and
analysis method, these measurements give tighter constraints than a previous
BAO analysis of the BOSS DR9 Lyman-alpha forest sample, providing an important
consistency test of the standard cosmological model in a new redshift regime.


title: Landau gauge fixing on the lattice using GPU's

abstract:
  In this work, we consider the GPU implementation of the steepest descent
method with Fourier acceleration for Laudau gauge fixing, using CUDA. The
performance of the code in a Tesla C2070 GPU is compared with a parallel CPU
implementation.


title: Factorized Topic Models

abstract:
  In this paper we present a modification to a latent topic model, which makes
the model exploit supervision to produce a factorized representation of the
observed data. The structured parameterization separately encodes variance that
is shared between classes from variance that is private to each class by the
introduction of a new prior over the topic space. The approach allows for a
more eff{}icient inference and provides an intuitive interpretation of the data
in terms of an informative signal together with structured noise. The
factorized representation is shown to enhance inference performance for image,
text, and video classification.


title:
Generic folding and transition hierarchies for surface adsorption of
  hydrophobic-polar lattice model proteins

abstract:
  The thermodynamic behavior and structural properties of hydrophobic-polar
(HP) lattice proteins interacting with attractive surfaces are studied by means
of Wang-Landau sampling. Three benchmark HP sequences (48mer, 67mer, and
103mer) are considered with different types of surfaces, each of which attract
either all monomers, only hydrophobic (H) monomers, or only polar (P) monomers,
respectively. The diversity of folding behavior in dependence of surface
strength is discussed. Analyzing the combined patterns of various structural
observables, such as, e.g., the derivatives of the numbers of surface contacts,
together with the specific heat, we are able to identify generic categories of
folding and transition hierarchies. We also infer a connection between these
transition categories and the relative surface strengths, i.e., the ratio of
the surface attractive strength to the interchain attraction among H monomers.
The validity of our proposed classification scheme is reinforced by the
analysis of additional benchmark sequences. We thus believe that the folding
hierarchies and identification scheme are generic for HP proteins interacting
with attractive surfaces, regardless of chain length, sequence, or surface
attraction.


title:
Uncertainties in Atomic Data and Their Propagation Through Spectral
  Models. I

abstract:
  We present a method for computing uncertainties in spectral models, i.e.
level populations, line emissivities, and emission line ratios, based upon the
propagation of uncertainties originating from atomic data. We provide analytic
expressions, in the form of linear sets of algebraic equations, for the coupled
uncertainties among all levels. These equations can be solved efficiently for
any set of physical conditions and uncertainties in the atomic data. We
illustrate our method applied to spectral models of O III and Fe II and discuss
the impact of the uncertainties on atomic systems under different physical
conditions. As to intrinsic uncertainties in theoretical atomic data, we
propose that these uncertainties can be estimated from the dispersion in the
results from various independent calculations. This technique provides
excellent results for the uncertainties in A-values of forbidden transitions in
[Fe II].

categories: astro-ph.IM astro-ph.CO physics.atom-ph physics.data-an


title:
Monte Carlo Simulation of Melting and Lattice Relaxation of the (111)
  Surface of Silver

abstract:
  It is experimentally observed and theoretically proved that the distance
between topmost layers of a metal surface has a contraction. However,
well-known potentials such as Lennard-Jones and Morse potentials lead to an
expansion of the surface inter-layer distance. Such simple potentials therefore
cannot be used to study metal surface relaxation. In this paper, extensive
Monte Carlo simulations are used to study the silver (111) surface with both
the Gupta potential (GP) and the Embedded Atom Method (EAM) potential. Our
results of the lattice relaxation at the (111) surface of silver show indeed a
contraction for both potentials at low temperatures in agreement with
experiments and early theories. However at higher temperatures, the EAM
potential yields a surface melting at $\simeq 700$ K very low with respect to
the experimental bulk melting at $\simeq 1235$ K while the GP yields a surface
melting at $\simeq 1000$ K closer to the bulk one. In addition, we observe with
the EAM potential an anomalous thermal expansion, i. e. the surface contraction
becomes a surface dilatation with respect to the bulk, at $\simeq 900$ K. The
Gupta potential does not show this behavior.We compare our results with
different experimental and numerical results.


title:
Search for $\alpha$ decay of $^{151}$Eu to the first excited level of
  $^{147}$Pm using underground $\gamma$-ray spectrometry

abstract:
  The alpha decay of $^{151}$Eu to the first excited level of $^{147}$Pm
($J^\pi = 5/2^+$, $E_{exc}=91.1$ keV) was searched for at the HADES underground
laboratory ($\approx 500$ m w.e.). A sample of high purity europium oxide with
mass of 303 g and a natural isotopic composition has been measured over 2232.8
h with a high energy resolution ultra-low background n-type semi-planar HPGe
detector (40 cm$^3$) with sub-micron deadlayer. The new improved half-life
limit has been set as $T_{1/2} \geq 3.7\times 10^{18}$ yr at 68% C.L.
Possibilities to improve the sensitivity of the experiment, which is already
near the theoretical predictions, are discussed. New half-life limit for
$\alpha$ decay of $^{153}$Eu is also set as $T_{1/2} \geq 5.5\times 10^{17}$
yr.


title:
Unraveling the beautiful complexity of simple lattice model polymers and
  proteins using Wang-Landau sampling

abstract:
  We describe a class of "bare bones" models of homopolymers which undergo
coil-globule collapse and proteins which fold into their native states in free
space or into denatured states when captured by an attractive substrate as the
temperature is lowered. We then show how, with the use of a properly chosen
trial move set, Wang-Landau Monte Carlo sampling can be used to study the rough
free energy landscape and ground (native) states of these intriguingly simple
systems and thus elucidate their thermodynamic complexity.


title:
Oxidation of In2S3 films to synthetize In2S3(1-x)O3x thin films as a
  buffer layer in solar cells

abstract:
  In2S3(1-x)O3x is known from preceding studies to have a bandgap varying
continuously as a function of x, the reason why this solid solution is
potentially interesting in the field of photovoltaics. In this work, we present
results on oxidation of In2S3 by heating in air atmosphere to obtain the
desired material. The oxidation is accompanied by a mass loss due to the
substitution of S by O atoms that is studied by means of thermogravimetric
analysis. It appears that the temperature region in which the oxidation occurs
is strongly dependent on the texture of deposited films. As-grown films
deposited by chemical bath deposition are subjected to nano-oxidation occurring
at lower temperature than oxidation of materials that are characterized by a
better crystallinity and larger crystallite size. X ray diffraction and
scanning electron microscopy (including EDX) were used to get information on
the compounds and the texture of films. The main conclusion of the paper opens
the perspective of practical applications for producing layers for solar cells.


title: Boltzmann Machines and Denoising Autoencoders for Image Denoising

abstract:
  Image denoising based on a probabilistic model of local image patches has
been employed by various researchers, and recently a deep (denoising)
autoencoder has been proposed by Burger et al. [2012] and Xie et al. [2012] as
a good model for this. In this paper, we propose that another popular family of
models in the field of deep learning, called Boltzmann machines, can perform
image denoising as well as, or in certain cases of high level of noise, better
than denoising autoencoders. We empirically evaluate the two models on three
different sets of images with different types and levels of noise. Throughout
the experiments we also examine the effect of the depth of the models. The
experiments confirmed our claim and revealed that the performance can be
improved by adding more hidden layers, especially when the level of noise is
high.


title:
Strain-dependent modulation of conductivity in single layer
  transition-metal dichalcogenides

abstract:
  Quantum conductance calculations on the mechanically deformed monolayers of
MoS$_2$ and WS$_2$ were performed using the non-equlibrium Green's functions
method combined with the Landauer-B\"{u}ttiker approach for ballistic transport
together with the density-functional based tight binding (DFTB) method. Tensile
strain and compression causes significant changes in the electronic structure
of TMD single layers and eventually the transition semiconductor-metal occurs
for elongations as large as ~11% for the 2D-isotropic deformations in the
hexagonal structure. This transition enhances the electron transport in
otherwise semiconducting materials.


title:
Mott insulators of ultracold fermionic alkaline earth atoms in three
  dimensions

abstract:
  We study a class of SU(N) Heisenberg models, describing Mott insulators of
fermionic ultra-cold alkaline earth atoms on the three-dimensional simple cubic
lattice. Based on an earlier semiclassical analysis, magnetic order is
unlikely, and we focus instead on a solvable large-N limit designed to address
the competition among non-magnetic ground states. We find a rich phase diagram
as a function of the filling parameter k, composed of a variety of ground
states spontaneously breaking lattice symmetries, and in some cases also time
reversal symmetry. One particularly striking example is a state spontaneously
breaking lattice rotation symmetry, where the cubic lattice breaks up into
bilayers, each of which forms a two-dimensional chiral spin liquid state.


title: Embedding a balanced binary tree on a bounded point set

abstract:
  Given an undirected planar graph G with n vertices and a set S of n points
inside a simple polygon P, a point-set embedding of G on S is a planar drawing
of G such that each vertex is mapped to a distinct point of S and the edges are
polygonal chains surrounded by P. A special case of the embedding problem is
that in which G is a balanced binary tree. In this paper, we present a new
algorithm for embedding an n-vertex balanced binary tree BBT on a set S of n
points bounded by a simple m-gon P in O(m^2 + n(log n)^2 + mn) time with at
most O(m) bends per edge.


title:
In vitro investigation of the effects of X- rays carried by a photon
  beam upon the cell cycle progression in Vero cells

abstract:
  The effects of the X-rays carried out in a photon beam produced by a medical
linear particle accelerator on the progression of the cell cycle in normal
cells Vero were evaluated by flow cytometric mean. The evaluation of the
consequences of 1 and 3 Gy irradiation upon cell cycle development was
performed after 96 and 120 hours from the exposure moment, in order to register
the late effects of irradiation. As compared with the control group (sham
exposed) the treated cells with the dose of 1 Gy have shown an increase of the
frequency of cells blocked in S and G2/M stages and also of the apoptotic cells
at 96 hours from the treatment. After another 24 hours, the frequency of the
blocked cells in S and G2/M has decreased. The response of the 96 hours cell
cultures to 3 Gy treatment was faster, as suggested by the increased number of
apoptotic cells and by reduced frequency of the arrested cells in S and G2/M.
The blockage of Vero cells in different phases of the cell-cycle and the
presence of active repairing systems reveals the reduced risk of the malignant
transformation of the exposed normal cells and could offer an enhanced cell
protection to another damaging agents.


title:
Semiparametric estimation of a two-component mixture of linear
  regressions in which one component is known

abstract:
  A new estimation method for the two-component mixture model introduced in
\cite{Van13} is proposed. This model consists of a two-component mixture of
linear regressions in which one component is entirely known while the
proportion, the slope, the intercept and the error distribution of the other
component are unknown. In spite of good performance for datasets of reasonable
size, the method proposed in \cite{Van13} suffers from a serious drawback when
the sample size becomes large as it is based on the optimization of a contrast
function whose pointwise computation requires O(n^2) operations. The range of
applicability of the method derived in this work is substantially larger as it
relies on a method-of-moments estimator free of tuning parameters whose
computation requires O(n) operations. From a theoretical perspective, the
asymptotic normality of both the estimator of the Euclidean parameter vector
and of the semiparametric estimator of the c.d.f.\ of the error is proved under
weak conditions not involving zero-symmetry assumptions. In addition, an
approximate confidence band for the c.d.f.\ of the error can be computed using
a weighted bootstrap whose asymptotic validity is proved. The finite-sample
performance of the resulting estimation procedure is studied under various
scenarios through Monte Carlo experiments. The proposed method is illustrated
on three real datasets of size $n=150$, 51 and 176,343, respectively. Two
extensions of the considered model are discussed in the final section: a model
with an additional scale parameter for the first component, and a model with
more than one explanatory variable.


title:
Solitary waves, periodic and elliptic solutions to the Benjamin, Bona &
  Mahony (BBM) equation modified by viscosity

abstract:
  In this paper, we use a traveling wave reduction or a so-called spatial
approximation to comprehensively investigate periodic and solitary wave
solutions of the modified Benjamin, Bona & Mahony equation (BBM) to include
both dissipative and dispersive effects of viscous boundary layers. Under
certain circumstances that depend on the traveling wave velocity, classes of
periodic and solitary wave like solutions are obtained in terms of Jacobi
elliptic functions. An ad-hoc theory based on the dissipative term is
presented, in which we have found a set of solutions in terms of an implicit
function. Using dynamical systems theory we prove that the solutions of
\eqref{BBMv} experience a transcritical bifurcation for a certain velocity of
the traveling wave. Finally, we present qualitative numerical results.


title:
Measurement of the inclusive differential jet cross section in pp
  collisions at $\sqrt{s}$ = 2.76 TeV

abstract:
  The ALICE collaboration at the CERN Large Hadron Collider reports the first
measurement of the inclusive differential jet cross section at mid-rapidity in
pp collisions at $\sqrt{s} = 2.76$ TeV, with integrated luminosity of 13.6
nb$^{-1}$. Jets are measured over the transverse momentum range 20 to 125 GeV/c
and are corrected to the particle level. Calculations based on Next-to-Leading
Order perturbative QCD are in good agreement with the measurements. The ratio
of inclusive jet cross sections for jet radii $R = 0.2$ and $R = 0.4$ is
reported, and is also well reproduced by a Next-to-Leading Order perturbative
QCD calculation when hadronization effects are included.


title:
Pushing Stochastic Gradient towards Second-Order Methods --
  Backpropagation Learning with Transformations in Nonlinearities

abstract:
  Recently, we proposed to transform the outputs of each hidden neuron in a
multi-layer perceptron network to have zero output and zero slope on average,
and use separate shortcut connections to model the linear dependencies instead.
We continue the work by firstly introducing a third transformation to normalize
the scale of the outputs of each hidden neuron, and secondly by analyzing the
connections to second order optimization methods. We show that the
transformations make a simple stochastic gradient behave closer to second-order
optimization methods and thus speed up learning. This is shown both in theory
and with experiments. The experiments on the third transformation show that
while it further increases the speed of learning, it can also hurt performance
by converging to a worse local optimum, where both the inputs and outputs of
many hidden neurons are close to zero.


title: Accelerations of generalized Fibonacci sequences

abstract:
  In this paper we study how to accelerate the convergence of the ratios (x_n)
of generalized Fibonacci sequences. In particular, we provide recurrent
formulas in order to generate subsequences (x_{g_n}) for every linear recurrent
sequence (g_n) of order 2. Using these formulas we prove that some
approximation methods, as secant, Newton, Halley and Householder methods, can
generate subsequences of (x_n). Moreover, interesting properties on Fibonacci
numbers arise as an application. Finally, we apply all the results to the
convergents of a particular continued fraction which represents quadratic
irrationalities.


title: Eta, Eta' and eLSM

abstract: We discuss the eta-eta' mixing in the Extended Linear Sigma Model (eLSM).


title: Deformations of Killing spinors on Sasakian and 3-Sasakian manifolds

abstract:
  We consider some natural infinitesimal Einstein deformations on Sasakian and
3-Sasakian manifolds. Some of these are infinitesimal deformations of Killing
spinors and further some integrate to actual Killing spinor deformations. In
particular, on 3-Sasakian 7 manifolds these yield infinitesimal Einstein
deformations preserving 2, 1, or none of the 3 independent Killing spinors.
Toric 3-Sasakian manifolds provide non-trivial examples with integrable
deformation preserving precisely 2 Killing spinors. Thus the dimension of
Killing spinors is not preserved under Einstein deformations but is only upper
semi-continuous.


title: Gauge networks in noncommutative geometry

abstract:
  We introduce gauge networks as generalizations of spin networks and lattice
gauge fields to almost-commutative manifolds. The configuration space of quiver
representations (modulo equivalence) in the category of finite spectral triples
is studied; gauge networks appear as an orthonormal basis in a corresponding
Hilbert space. We give many examples of gauge networks, also beyond the
well-known spin network examples. We find a Hamiltonian operator on this
Hilbert space, inducing a time evolution on the C*-algebra of gauge network
correspondences.
  Given a representation in the category of spectral triples of a quiver
embedded in a spin manifold, we define a discretized Dirac operator on the
quiver. We compute the spectral action of this Dirac operator on a
four-dimensional lattice, and find that it reduces to the Wilson action for
lattice gauge theories and a Higgs field lattice system. As such, in the
continuum limit it reduces to the Yang-Mills-Higgs system. For the
three-dimensional case, we relate the spectral action functional to the
Kogut-Susskind Hamiltonian.


title: Manipulation of Ferromagnets via the Spin-Selective Optical Stark Effect

abstract:
  We investigate the non-resonant all-optical switching of magnetization. We
treat the inverse Faraday effect (IFE) theoretically in terms of the
spin-selective optical Stark effect for linearly or circularly polarized light.
In the dilute magnetic semiconductors (Ga,Mn)As, strong laser pulses below the
band gap induce effective magnetic fields of several teslas in a direction
which depends on the magnetization and light wave vectors. Our theory
demonstrates that the polarized light catalyzes the angular momentum transfer
between lattice and the magnetization.


title: Many to Many Matching with Demands and Capacities

abstract:
  Let A and B be two finite sets of points with total cardinality n, the many
to many point matching with demands and capacities matches each point ai in A
to at least alpha'i and at most alphai points in B, and each point bj in B to
at least betaj and at most beta'j points in A for all 1 <= i <= s and 1 <= j <=
t. In this paper, we present an upper bound for this problem using our new
polynomial time algorithm.


title: Nucleation rate of color superconducting droplets in protoneutron stars

abstract:
  We analyse the nucleation of quark matter droplets under protoneutron star
conditions. We adopt a two-phase framework in which the hadronic phase is
described through a non-linear Walecka model and the just deconfined matter by
the MIT bag model including color superconductivity. Surface tension and
curvature energy are calculated self-consistently within the MRE formalism. We
impose flavour conservation during the transition, which means that the just
deconfined quark droplet is transiently out of equilibrium with respect to weak
interactions. Our results show that trapped neutrinos slightly increase the
critical density for deconfinement and that color superconductivity
significantly decreases such density at low temperatures. We also show that the
nucleation rate is negligible for droplets larger than 100-200 fm and is huge
for smaller droplets provided that the temperature is low enough. We compare
our results with previous calculations using the Nambu-Jona-Lasinio model with
color superconductivity and the MIT bag model without color superconductivity.
We conclude that the deconfinement transition should be triggered
instantaneously when a density slightly larger than the bulk transition density
is reached at some layer of a protoneutron star. Since color superconductivity
lowers the transition density at low temperatures, the transition is likely to
occur after significant cooling in a massive enough protoneutron star.


title: Asymptotic dimension, decomposition complexity, and Haver's property C

abstract:
  The notion of the decomposition complexity was introduced in \cite{GTY} using
a game theoretical approach. We introduce a notion of straight decomposition
complexity and compare it with the original as well with the asymptotic
property C. Then we define a game theoretical analog of Haver's property C in
the classical dimension theory and compare it with the original.


title:
A Semantic Matching Energy Function for Learning with Multi-relational
  Data

abstract:
  Large-scale relational learning becomes crucial for handling the huge amounts
of structured data generated daily in many application domains ranging from
computational biology or information retrieval, to natural language processing.
In this paper, we present a new neural network architecture designed to embed
multi-relational graphs into a flexible continuous vector space in which the
original data is kept and enhanced. The network is trained to encode the
semantics of these graphs in order to assign high probabilities to plausible
components. We empirically show that it reaches competitive performance in link
prediction on standard datasets from the literature.


title: Backbone scaling limit of the high-dimensional IIC

abstract:
  We identify the scaling limit of the backbone of the high-dimensional
incipient infinite cluster (IIC), both in the long- as well as in the
finite-range setting. In the finite-range setting, this scaling limit is
Brownian motion, in the long-range setting, it is a stable motion. The proof
relies on a novel lace expansion for percolation that resembles the original
expansion for self-avoiding walks by Brydges and Spencer in 1985. This
expansion is interesting in its own right.


title:
Dynamical localization in kicked rotator as a paradigm of other systems:
  spectral statistics and the localization measure

abstract:
  We study the intermediate statistics of the spectrum of quasi-energies and of
the eigenfunctions in the kicked rotator, in the case when the corresponding
system is fully chaotic while quantally localized. As for the eigenphases, we
find clear evidence that the spectral statistics is well described by the Brody
distribution, notably better than by the Izrailev's one, which has been
proposed and used broadly to describe such cases. We also studied the
eigenfunctions of the Floquet operator and their localization. We show the
existence of a scaling law between the repulsion parameter with relative
localization length, but only as a first order approximation, since another
parameter plays a role. We believe and have evidence that a similar analysis
applies in time-independent Hamilton systems.


title: Various improvements to text fingerprinting

abstract:
  Let s = s_1 .. s_n be a text (or sequence) on a finite alphabet \Sigma of
size \sigma. A fingerprint in s is the set of distinct characters appearing in
one of its substrings. The problem considered here is to compute the set {\cal
F} of all fingerprints of all substrings of s in order to answer efficiently
certain questions on this set. A substring s_i .. s_j is a maximal location for
a fingerprint f in F (denoted by <i,j>) if the alphabet of s_i .. s_j is f and
s_{i-1}, s_{j+1}, if defined, are not in f. The set of maximal locations ins is
{\cal L} (it is easy to see that |{\cal L}| \leq n \sigma). Two maximal
locations <i,j> and <k,l> such that s_i .. s_j = s_k .. s_l are named {\em
copies}, and the quotient set of {\cal L} according to the copy relation is
denoted by {\cal L}_C. We present new exact and approximate efficient
algorithms and data structures for the following three problems: (1) to compute
{\cal F}; (2) given f as a set of distinct characters in \Sigma, to answer if f
represents a fingerprint in {\cal F}; (3) given f, to find all maximal
locations of f in s.


title: Maximizing the mode instability threshold of a fiber amplifier

abstract:
  We show by detailed numerical modeling that stimulated thermal Rayleigh
scattering can account for the modal instability observed in high power fiber
amplifiers. Our model illustrates how the instability threshold power can be
maximized by eliminating amplitude and phase modulation of the signal seed and
the pump, and by careful launch of the signal seed. We also illustrate the
influence of photodarkening and mode specific loss on the threshold.


title: Nonradial solutions for the H\'enon equation in $R^N$

abstract:
  In this paper we consider the problem $$ {ll} -\Delta
u=(N+\a)(N-2)|x|^{\a}u^\frac{N+2+2\a}{N-2} & in R^N u>0& in R^N u\in
D^{1,2}(R^N). $$ where $N\ge3$. From the characterization of the solutions of
the linearized operator, we deduce the existence of nonradial solutions which
bifurcate from the radial one when $\alpha$ is an even integer.


title:
Did the infant R136 and NGC 3603 clusters undergo residual gas
  expulsion?

abstract:
  Based on kinematic data observed for very young, massive clusters that appear
to be in dynamical equilibrium, it has recently been argued that such young
systems set examples where the early residual gas-expulsion did not happen or
had no dynamical effect. The intriguing scenario of a star cluster forming
through a single starburst has thereby been challenged. Choosing the case of
the R136 cluster of the Large Magellanic Cloud, the most cited one in this
context, we perform direct N-body computations that mimic the early evolution
of this cluster including the gas-removal phase (on a thermal timescale). Our
calculations show that under plausible initial conditions as consistent from
observational data, a large fraction (> 60%) of a gas-expelled, expanding
R136-like cluster is bound to regain dynamical equilibrium by its current age.
Therefore, the recent measurements of velocity dispersion in the inner regions
of R136, that indicate that the cluster is in dynamical equilibrium, are
consistent with an earlier substantial gas expulsion of R136 followed by a
rapid re-virialization (in approx. 1 Myr). Additionally, we find that the less
massive Galactic NGC 3603 Young Cluster (NYC), with a substantially longer
re-virialization time, is likely to be found deviated from dynamical
equilibrium at its present age (approx. 1 Myr). The recently obtained stellar
proper motions in the central part of the NYC indeed suggest this and are
consistent with the computed models. This work significantly extends previous
models of the Orion Nebula Cluster which already demonstrated that the
re-virialization time of young post-gas-expulsion clusters decreases with
increasing pre-expulsion density.


title: Higgs Boson self-coupling measurements using ratios of cross sections

abstract:
  We consider the ratio of cross sections of double-to-single Higgs boson
production at the Large Hadron Collider at 14 TeV. Since both processes possess
similar higher-order corrections, leading to a cancellation of uncertainties in
the ratio, this observable is well-suited to constrain the trilinear Higgs
boson self-coupling. We consider the scale variation, parton density function
uncertainties and conservative estimates of experimental uncertainties, applied
to the viable decay channels, to construct expected exclusion regions. We show
that the trilinear self-coupling can be constrained to be positive with a
600/fb LHC dataset at 95% confidence level. Moreover, we demonstrate that we
expect to obtain a ~+30% and ~-20 uncertainty on the self-coupling at 3000/fb
without statistical fitting of differential distributions. The present article
outlines the most precise method of determination of the Higgs trilinear
coupling to date.


title: Bottom Mass from Nonrelativistic Sum Rules at NNLL

abstract:
  We report on a recent determination of the bottom quark mass from
nonrelativistic (large-n) Upsilon sum rules with renormalization group
improvement (RGI) at next-to-next-to-leading logarithmic (NNLL) order. The
comparison to previous fixed-order analyses shows that the RGI computed in the
vNRQCD framework leads to a substantial stabilization of the theoretical sum
rule moments with respect to scale variations. A single moment fit (n=10) to
the available experimental data yields M_b^{1S}=4.755 +- 0.057(pert) +-
0.009(alpha_s) +- 0.003(exp) GeV for the bottom 1S mass and m_b(m_b)= 4.235 +-
0.055(pert) +- 0.003(exp) GeV for the bottom MSbar mass. The quoted
uncertainties refer to the perturbative error and the uncertainties associated
with the strong coupling and the experimental input.


title: Real-Space Parallel Density Matrix Renormalization Group

abstract:
  We demonstrate how to parallelize the density matrix renormalization group
(DMRG) algorithm in real space through a straightforward modification of serial
DMRG. This makes it possible to apply at least an order of magnitude more
computational power to challenging simulations, greatly accelerating
investigations of two-dimensional systems and large parameter spaces. We
discuss details of the algorithm and present benchmark results including a
study of valence-bond-solid order within the square-lattice Q2 model and Neel
order within the triangular lattice Heisenberg model. The parallel DMRG
algorithm also motivates an alternative canonical form for matrix product
states.


title: Mechanisms for Sub-Gap Optical Conductivity in Herbertsmithite

abstract:
  Recent terahertz conductivity measurements observed low-power-law frequency
dependence of optical conduction within the Mott gap of the Kagome lattice
spin-liquid candidate Herbertsmithite. We investigate mechanisms for this
observed sub-gap conductivity for two possible scenarios in which the
ground-state is described by: 1) a U(1) Dirac spin-liquid with emergent
fermionic spinons or 2) a nearly critical Z2 spin-liquid in the vicinity of a
continuous quantum phase transition to magnetic order. We identify new
mechanisms for optical-absorption via magneto-elastic effects and spin- orbit
coupling. In addition, for the Dirac spin-liquid scenario, we establish an
explicit microscopic origin for previously proposed absorption mechanisms based
on slave-particle effective field theory descriptions.


title:
An experimental proposal for revealing contextuality in almost all
  qutrit states

abstract:
  Contextuality is a foundational phenomenon underlying key differences between
quantum theory and classical realistic descriptions of the world. Here we
propose an experimental test which is capable of revealing contextuality in all
qutrit systems, except the completely mixed state, provided we choose the
measurement basis appropriately. The 3-level system is furnished by the
polarization and spatial degrees of freedom of a single photon, which encompass
three orthogonal modes. Projective measurements along rays in the 3-dimensional
Hilbert space are made by linear optical elements and detectors which are
sensitive to a single mode. We also discuss the impact of detector inefficiency
and losses and review the theoretical foundations of this test.


title: How robust are predictions of galaxy clustering?

abstract:
  We use the Millennium Simulation database to compare how different versions
of the Durham and Munich semi-analytical galaxy formation models populate dark
matter haloes with galaxies. The models follow the same physical processes but
differ in how these are implemented. All of the models we consider use the
Millennium N-body Simulation; however, the Durham and Munich groups use
independent algorithms to construct halo merger histories. We compare the
predicted halo occupation distributions (HODs) and correlation functions for
galaxy samples defined by stellar mass, cold gas mass and star formation rate.
The predictions for the HOD are remarkably similar for samples ranked by
stellar mass. The predicted bias averaged over 5-25 Mpc/h is consistent between
models to within 10%. At small pair separations there is a difference in the
predicted clustering. This arises because the Durham models allow some
satellite galaxies to merge with the central galaxy in a halo when they are
still associated with resolved subhaloes. The agreement between the models is
less good for samples defined by cold gas mass or star formation rate, with the
small scale clustering differing by an order of magnitude, reflecting the
uncertainty in the modelling of star formation. The model predictions in these
cases are qualitatively similar, with a markedly shallower slope for the
correlation function than is found for stellar mass selected samples and with
the HOD displaying an asymmetric peak for central galaxies. We provide
illustrative parametric fits to the HODs predicted by the models. Our results
reveal the current limitations on how well we can predict galaxy bias in a
fixed cosmology, which has implications for the interpretation of constraints
on the physics of galaxy formation from galaxy clustering measurements and the
ability of future galaxy surveys to measure dark energy.


title: The CO-to-H2 Conversion Factor

abstract:
  CO line emission represents the most accessible and widely used tracer of the
molecular interstellar medium. This renders the translation of observed CO
intensity into total H2 gas mass critical to understand star formation and the
interstellar medium in our Galaxy and beyond. We review the theoretical
underpinning, techniques, and results of efforts to estimate this CO-to-H2
"conversion factor," Xco, in different environments. In the Milky Way disk, we
recommend a conversion factor Xco = 2x10^{20} cm^-2/(K km/s)^-1 with +/-30%
uncertainty. Studies of other "normal galaxies" return similar values in Milky
Way-like disks, but with greater scatter and systematic uncertainty. Departures
from this Galactic conversion factor are both observed and expected. Dust-based
determinations, theoretical arguments, and scaling relations all suggest that
Xco increases with decreasing metallicity, turning up sharply below metallicity
~1/3-1/2 solar in a manner consistent with model predictions that identify
shielding as a key parameter. Based on spectral line modeling and dust
observations, Xco appears to drop in the central, bright regions of some but
not all galaxies, often coincident with regions of bright CO emission and high
stellar surface density. This lower Xco is also present in the overwhelmingly
molecular interstellar medium of starburst galaxies, where several lines of
evidence point to a lower CO-to-H2 conversion factor. At high redshift, direct
evidence regarding the conversion factor remains scarce; we review what is
known based on dynamical modeling and other arguments.


title: AGN Jet Kinetic Power and the Energy Budget of Radio Galaxy Lobes

abstract:
  Recent results based on the analysis of radio galaxies and their hot X-ray
emitting atmospheres suggest that non-radiating particles dominate the energy
budget in the lobes of FRI radio galaxies, in some cases by a factor of more
than 1000, while radiating particles dominate the energy budget in FRII radio
galaxy lobes. This implies a significant difference in the radiative efficiency
of the two morphological classes. To test this hypothesis, we have measured the
kinetic energy flux for a sample of 3C FRII radio sources using a new method
based on the observed parameters of the jet terminal hotspots, and compared the
resulting Q(jet) - L(radio) relation to that obtained for FRI radio galaxies
based on X-ray cavity measurements. Contrary to expectations, we find
approximate agreement between the Q(jet) - L(radio) relations determined
separately for FRI and FRII radio galaxies. This result is ostensibly difficult
to reconcile with the emerging scenario in which the lobes of FRI and FRII
radio galaxies have vastly different energy budgets. However, a combination of
lower density environment, spectral ageing and strong shocks driven by powerful
FRII radio galaxies may reduce the radiative efficiency of these objects
relative to FRIs and couteract, to some extent, the higher radiative efficiency
expected to arise due to the lower fraction of energy in non-radiating
particles. An unexpected corollary is that extrapolating the Q(jet) - L(radio)
relation determined for low power FRI radio galaxies provides a reasonable
approximation for high power sources, despite their apparently different lobe
compositions.


title:
Discovery of X-ray emission from young suns in the Small Magellanic
  Cloud

abstract:
  We report the discovery of extended X-ray emission within the young star
cluster NGC 602 in the Wing of the Small Magellanic Cloud (SMC) based on
observations obtained with the Chandra X-ray Observatory. X-ray emission is
detected from the cluster core area with the highest stellar density and from a
dusty ridge surrounding the HII region. We use a census of massive stars in the
cluster to demonstrate that a cluster wind or wind-blown bubble is unlikely to
provide a significant contribution to the X-ray emission detected from the
central area of the cluster. We therefore suggest that X-ray emission at the
cluster core originates from an ensemble of low- and solar-mass
pre-main-sequence (PMS) stars, each of which would be too weak in X-rays to be
detected individually. We attribute the X-ray emission from the dusty ridge to
the embedded tight cluster of the new-born stars known in this area from
infrared studies. Assuming that the levels of X-ray activity in young stars in
the low-metallicity environment of NGC 602a are comparable to their Galactic
counterparts, then the detected spatial distribution, spectral properties, and
level of X-ray emission are largely consistent with those expected from low-
and solar-mass PMS stars and young stellar objects (YSOs). This is the first
discovery of X-ray emission attributable to PMS stars and YSOs in the SMC,
which suggests that the accretion and dynamo processes in young, low-mass
objects in the SMC resemble those in the Galaxy.


title:
Spin Induced Optical Conductivity in the Spin Liquid Candidate
  Herbertsmithite

abstract:
  A quantum spin liquid (QSL) is a state of matter in which magnetic spins
interact strongly, but quantum fluctuations inhibit long-range magnetic order
even at zero temperature. A QSL has been predicted to have a host of exotic
properties, including fractionalized excitations and long-range quantum
entanglement. Despite the numerous theoretical studies, experimental
realization of a QSL has proved to be challenging due to the lack of candidate
materials. The triangular organic salts EtMe3Sb[Pd(dmit)2]2 and
{\kappa}-(BEDT-TTF)2Cu2(CN)3, and kagome ZnCu3(OH)6Cl2 (Herbertsmithite) have
recently emerged as promising candidates of exhibiting a QSL state, but the
nature of their ground states is still elusive. Here we studied a large-area
high-quality single crystal of Herbertsmithite by means of time-domain
terahertz (THz) spectroscopy. We observed in the low-frequency (0.6-2.2 THz)
optical conductivity evidence for the nature of the spin system. In particular,
the in-plane absorption spectrum exhibits a unique frequency dependence that
can be described by a power-law with an exponent of approximately 1.4, in sharp
contrast with the {\omega}^4 dependence expected for an ordered Mott insulator.
The absorption is also found to increase as the temperature decreases, a
behavior unexpected for conventional insulators. Such features are consistent
with recent theory based on the interactions between the charge and spin
degrees of freedom in a QSL system.


title:
The development of the Heliometer of the Observatorio Nacional of Rio de
  Janeiro and application to the study of the Sun-Earth system

abstract:
  This work presents the development and construction of the Heliometer of the
Observat\'orio Nacional/MCTI. This instrument is designed to monitor changes on
the solar diameter with the accuracy of the next-generation solar satellites. A
review of the heliometric method is made and the building and testing of 4
prototypes is described. The instrument has a mirror objective split in
dihedral, formed by the hemi-sections of a parabolic mirror. The materials that
form the instrument have thermal and mechanical stability to 10^(-7). The
number of optical parts is minimized and their quality is greater than
{\lambda}/12. An original software for the automated collection and analysis of
the images was developed. With its latest version fully developed, we conducted
an observational campaign of 9 days, deriving more than 70000 heliometric
images of the Sun. The measured solar diameter has a standard deviation of 0.5
arcseconds, with no instrumental bias, and limited only by the provisional
atmospheric modeling. Therefore, by improving the statistics, an accuracy at
milliarcseconds can be achieved. A study of the correlation between the solar
diameter and the geomagnetic field intensity was made. A correspondence between
the peaks of the series related to solar activity, namely, the semidiameter
variation, the flares index, and the sunspots counts, and the number of
negative peaks on the intensity of the geomagnetic field is found. It must be
cautioned though that it is a complex correspondence, requiring different modes
of response and phase dependence on the stage of the cycle of solar activity.
The straightforward interpretation of observational evidence indicates that the
semidiameter of the Sun seems to vary significantly prior to the corresponding
variations of the geomagnetic field. The effect is most evident in the downward
phase of the solar cycle.


title:
Direct measurement of time-dependent density-density correlations in a
  solid through the acoustic analog of the dynamical Casimir effect

abstract:
  The macroscopic characteristics of a solid, such as its thermal, optical or
transport properties are determined by the available microscopic states above
its lowest energy level. These slightly higher quantum states are described by
elementary excitations and dictate the response of the system under external
stimuli. The spectrum of these excitations, obtained typically from inelastic
neutron and x-ray scattering, is the spatial and temporal Fourier transform of
the density-density correlation function of the system, which dictates how a
perturbation propagates in space and time. As frequency-domain measurements do
not generally contain phase information, time-domain measurements of these
fluctuations could yield a more direct method for investigating the excitations
of solids and their interactions both in equilibrium and far-from equilibrium.
Here we show that the diffuse scattering of femtosecond x-ray pulses produced
by a free electron laser (FEL) can directly measure these density-density
correlations due to lattice vibrations in the time domain. We obtain
spectroscopic information of the lattice excitations with unprecedented
momentum- and frequency- resolution, without resolving the energy of the
outgoing photon. Correlations are created via an acoustic analog of the
dynamical Casimir effect, where a femtosecond laser pulse slightly quenches the
phonon frequencies, producing pairs of squeezed phonons at momenta +q and -q.
These pairs of phonons manifest as macroscopic, time-dependent coherences in
the displacement correlations that are then probed directly by x-ray
scattering. Since the time-dependent correlations are preferentially created in
regions of strong electron-phonon coupling, the time-resolved approach is
natural as a spectroscopic tool of low energy collective excitations in solids,
and their microscopic interactions, both in linear response and beyond.


title:
Integration of collinear-type doubly unresolved counterterms in NNLO jet
  cross sections

abstract:
  In the context of a subtraction method for jet cross sections at NNLO
accuracy in the strong coupling, we perform the integration over the
two-particle factorised phase space of the collinear-type contributions to the
doubly unresolved counterterms. We present the final result as a convolution in
colour space of the Born cross section and of an insertion operator, which is
written in terms of master integrals that we expand in the dimensional
regularisation parameter.


title:
Highly-Efficient Thermoelectronic Conversion of Solar Energy and Heat
  into Electric Power

abstract:
  Electric power may, in principle, be generated in a highly efficient manner
from heat created by focused solar irradiation, chemical combustion, or nuclear
decay by means of thermionic energy conversion. As the conversion efficiency of
the thermionic process tends to be degraded by electron space charges, the
efficiencies of thermionic generators have amounted to only a fraction of those
fundamentally possible. We show that this space-charge problem can be resolved
by shaping the electric potential distribution of the converter such that the
static electron space-charge clouds are transformed into an output current.
Although the technical development of practical generators will require further
substantial efforts, we conclude that a highly efficient transformation of heat
to electric power may well be achieved.


title: Distant galaxy clusters in a deep XMM-Newton field within the CFTHLS D4

abstract:
  The XMM-Newton Distant Cluster Project (XDCP) aims at the identification of a
well defined sample of X-ray selected clusters of galaxies at redshifts z>0.8.
We present a catalogue of the extended sources in one the deepest ~250 ksec
XMM-Newton fields targeting LBQS 2215-175 covering the CFHTLS deep field four.
The cluster identification is based, among others, on deep imaging with the ESO
VLT and from the CFHT legacy survey. The confirmation of cluster candidates is
done by VLT/FORS2 multi-object spectroscopy. Photometric redshifts from the
CFHTLS D4 are utilized to confirm the effectiveness of the X-ray cluster
selection method. The survey sensitivity is computed with extensive
simulations. At a flux limit of S(0.5-2.0 keV) ~ 2.5e-15 erg/s we achieve a
completeness level higher than 50% in an area of ~0.13 square degrees. We
detect six galaxy clusters above this limit with optical counterparts, of which
5 are new spectroscopic discoveries. Two newly discovered X-ray luminous galaxy
clusters are at z>1.0, another two at z=0.41 and one at z=0.34. For the most
distant X-ray selected cluster in this field at z=1.45 we find additional
(active) member galaxies from both X-ray and spectroscopic data. Additionally,
we find evidence of large scale structures at moderate redshifts of z=0.41 and
z=0.34. The quest for distant clusters in archival XMM-Newton data has led to
the detection of six clusters in a single field, making XMM-Newton an
outstanding tool for cluster surveys. Three of these clusters are at z>1, which
emphasises the valuable contribution of small, yet deep surveys to cosmology.
Beta-models are appropriate descriptions for the cluster surface brightness to
perform cluster detection simulations in order to compute the X-ray selection
function. The constructed logN-logS tends to favour a scenario where no
evolution in the cluster X-ray luminosity function (XLF) takes place.


title:
Central Diffraction in Proton-Proton Collisions at $\sqrt{s}=7$\,TeV
  with ALICE at LHC

abstract:
  A double-gap topology is used for filtering central-diffractive events from a
proton-proton minimum-bias data sample at a centre-of-mass energy
{$\sqrt{s}=7$\,TeV}. This topology is defined by particle activity in the ALICE
central barrel and absence of particle activity outside. The fraction of events
satisfying the double-gap requirement $R_{DG}$ is found to be
{$7.63\pm0.02(stat.)\pm0.87(syst.)\times 10^{-4}$}. The background of this
double-gap fraction is estimated by studying the contributions of
non-diffractive, single- and double-diffractive dissociation processes as
modelled by Monte Carlo event generators, and is found to be about 10%.