title:
Binary-corrected velocity dispersions from single- and multi-epoch
  radial velocities: massive stars in R136 as a test case

abstract:
  Orbital motions from binary stars can broaden the observed line-of-sight
velocity distribution of a stellar system, artificially inflating the measured
line-of-sight velocity dispersion, which can in turn lead to erroneous
conclusions about the dynamical state of the system. Cottaar et al. (2012b)
proposed a maximum likelihood procedure to recover the intrinsic velocity
dispersion of a resolved star cluster from a single epoch of radial velocity
data of individual stars, which they achieved by simultaneously fitting the
intrinsic velocity distribution of the single stars and the centres of mass of
the binaries along with the velocity shifts caused by binary orbital motions.
Assuming well-characterized binary properties, they showed that this procedure
can accurately reproduce intrinsic velocity dispersions below 1 km s$^{-1}$ for
solar-type stars. Here we investigate the systematic offsets induced in cases
where the binary properties are uncertain, and we show how two epochs of radial
velocity data with an appropriate baseline can help to mitigate these
systematic effects. We first test the method above using Monte Carlo
simulations, taking into account the large uncertainties in the binary
properties of OB stars. We then apply it to radial velocity data in the young
massive cluster R136, an example for which the intrinsic velocity dispersion of
O-type stars is known from an intensive multi-epoch approach. For typical
velocity dispersions of young massive clusters ($\gtrsim 4$ km s$^{-1}$) and
with a single epoch of data, we demonstrate that the method can just about
distinguish between a cluster in virial equilibrium and an unbound cluster.
This is due to the higher spectroscopic binary fraction and more loosely
constrained distributions of orbital parameters of OB stars compared to
solar-type stars. By extending the maximum likelihood method to multi-epoch
data, <abridged>


title: Reversing Palindromic Enumeration in Rank Two Free Groups

abstract:
  The Gilman-Maskit algorithm for determining the discreteness or
non-discreteness of a two-generator subgroup of $\mathrm{PSL}_2\mathbb{R}$
terminates with a pair of generators that are Farey words. The Farey words are
primitive words that are indexed by rational numbers and infinity. The E-words,
primitive words with palindromic product forms, are also indexed by rational
numbers and infinity. We show a modification of the Gilman-Maskit algorithm so
that the stopping generators are E-words.


title: Score-based Causal Learning in Additive Noise Models

abstract:
  Given data sampled from a number of variables, one is often interested in the
underlying causal relationships in the form of a directed acyclic graph. In the
general case, without interventions on some of the variables it is only
possible to identify the graph up to its Markov equivalence class. However, in
some situations one can find the true causal graph just from observational
data, for example in structural equation models with additive noise and
nonlinear edge functions. Most current methods for achieving this rely on
nonparametric independence tests. One of the problems there is that the null
hypothesis is independence, which is what one would like to get evidence for.
We take a different approach in our work by using a penalized likelihood as a
score for model selection. This is practically feasible in many settings and
has the advantage of yielding a natural ranking of the candidate models. When
making smoothness assumptions on the probability density space, we prove
consistency of the penalized maximum likelihood estimator. We also present
empirical results for simulated scenarios and real two-dimensional data sets
(cause-effect pairs) where we obtain similar results as other state-of-the-art
methods.


title: Performance Guarantees for Adaptive Estimation of Sparse Signals

abstract:
  This paper studies adaptive sensing for estimating the nonzero amplitudes of
a sparse signal with the aim of providing analytical guarantees on the
performance gain due to adaptive resource allocation. We consider a previously
proposed optimal two-stage policy for allocating sensing resources. For
positive powers q, we derive tight upper bounds on the mean qth-power error
resulting from the optimal two-stage policy and corresponding lower bounds on
the improvement over non-adaptive uniform sensing. It is shown that the
adaptation gain is related to the detectability of nonzero signal components as
characterized by Chernoff coefficients, thus quantifying analytically the
dependence on the sparsity level of the signal, the signal-to-noise ratio, and
the sensing resource budget. For fixed sparsity levels and increasing
signal-to-noise ratio or sensing budget, we obtain the rate of convergence to
oracle performance and the rate at which the fraction of resources spent on the
first exploratory stage decreases to zero. For a vanishing fraction of nonzero
components, the gain increases without bound as a function of signal-to-noise
ratio and sensing budget. Numerical simulations demonstrate that the bounds on
adaptation gain are quite tight in non-asymptotic regimes as well.


title:
Formation of ultracold LiRb molecules by photoassociation near the Li
  (2s 2S1/2) + Rb (5p 2P1/2) asymptote

abstract:
  We report the production of ultracold 7Li85Rb molecules by photoassociation
(PA) below the Li (2s 2S1/2) + Rb (5p 2P1/2) asymptote. We perform PA
spectroscopy in a dual-species 7Li-85Rb magneto-optical trap (MOT) and detect
the PA resonances using trap loss spectroscopy. We observe several strong PA
resonances corresponding to the last few bound states, assign the lines and
derive the long range C6 dispersion coefficients for the Li (2s 2S1/2) + Rb (5p
2P1/2) asymptote. We also report an excited-state molecule formation rate
(P_LiRb) of ~10^7 s^-1 and a PA rate coefficient (K_PA) of ~4x10^-11 cm^3/s,
which are both among the highest observed for heteronuclear bi-alkali
molecules. These suggest that PA is a promising route for the creation of
ultracold ground state LiRb molecules.


title:
Calculating the contribution of different binding modes to Quinacrine -
  DNA complex formation from polarized fluorescence data

abstract:
  Binding of acridine derivative quinacrine (QA) to chicken erythrocyte DNA was
studied by methods of absorption and polarized fluorescent spectroscopy.
Measurements were carried out in aqueous buffered solutions (pH 6.9) of
different dye concentrations (QA concentration range from $10^{-6}$ till
$10^{-4}$ M) and ionic strengths ($Na^{+}$ concentration rang from $10^{-3}$
till 0.15 M) in a wide range of phosphate-to-dye molar ratios ($P/D$). It is
established that the minimum of fluorescent titration curve plotted as relative
fluorescence intensity $vs$ $P/D$ is conditioned by the competition between the
two types of QA binding to DNA which posses by different emission parameters:
(i) intercalative one dominating under high $P/D$ values, and (ii) outside
electrostatic binding dominating under low $P/D$ values, which is accompanied
by the formation of non-fluorescent dye associates on the DNA backbone.
Absorption and fluorescent characteristics of complexes formed were determined.
The method of calculation of different binding modes contribution to the
complex formation depending on $P/D$ value is presented. It was shown that the
size of binding site measured as the number of DNA base pairs per one QA
molecule bound in the case of the electrostatic interaction is 8 times less
than that for the intercalative one that determines the competitive ability of
the outside binding against the stronger intercalative binding mode.


title:
Vibronic speed-up of the excitation energy transfer in the
  Fenna-Matthews-Olson complex

abstract:
  We show that the efficient excitation energy transfer in the
Fenna-Matthews-Olson molecular aggregate under realistic physiological
conditions is fueled by underdamped vibrations of the embedding proteins. For
this, we present numerically exact results for the quantum dynamics of the
excitons in the presence of nonadiabatic vibrational states in the
Fenna-Matthews-Olson aggregate employing a environmental fluctuation spectral
function derived from experiments. Assuming the prominent 180 cm$^{-1}$
vibrational mode to be underdamped, we observe, on the one hand, besides
vibrational coherent oscillations between different excitation levels of the
vibration also prolonged electronic coherent oscillations between the initially
excited site and its neighbours. On the other hand, however, the underdamped
vibrations provide additional channels for the excitation energy transfer and
by this increase the transfer speed by up to $30\%$ .

categories: physics.chem-ph cond-mat.stat-mech physics.atm-clus physics.atom-ph


title: Quartic residues and sums involving $\binom{4k}{2k}$

abstract:
  Let $p$ be an odd prime and let $m\not\equiv 0\pmod p$ be a rational p-adic
integer. In this paper we reveal the connection between quartic residues and
the sum $\sum_{k=0}^{[p/4]}\binom{4k}{2k}\frac 1{m^k}$, where $[x]$ is the
greatest integer not exceeding $x$. Let $q$ be a prime of the form $4k+1$ and
so $q=a^2+b^2$ with $a,b\in\Bbb Z$. When $p\nmid ab(a^2-b^2)q$, we show that
for $r=0,1,2,3$, $p^{\frac{q-1}4}\equiv (\frac ab)^r\pmod q$ if and only if
$$\sum_{k=0}^{[p/4]}\binom{4k}{2k}\Big(\frac{a^2}{16q}\Big)^k\equiv
(-1)^{\frac{p^2-1}8a+\frac{p-1}2\cdot \frac{q-1}4}\Big(\frac pq\Big) \Big(\frac
ab\Big)^r\pmod p,$$ where $(\frac pq)$ is the Legendre symbol. We also
establish congruences for $\sum_{k=0}^{[p/4]}\binom{4k}{2k}\frac 1{m^k}\pmod p$
in the cases $m=17,18,20,32,52,80,272$.


title:
Modified Dynamical Supergravity Breaking and Off-Diagonal Super-Higgs
  Effects

abstract:
  We argue that generic off-diagonal vacuum and nonvacuum solutions for
Einstein manifolds mimic physical effects in modified gravity theories (MGTs)
and encode certain models of the $f(R,T,...)$, Ho\v{r}ava type with dynamical
Lorentz symmetry breaking, induced effective mass for the graviton etc. Our
main goal is to investigate the dynamical breaking of local supersymmetry
determined by off-diagonal solutions in MGTs and encoded as effective Einstein
spaces. This includes the Deser-Zumino super-Higgs effect, for instance, for a
one-loop potential in a (simple but representative) model of $\mathcal{N}=1,
D=4$ supergravity. We develop and apply new geometrical techniques which allows
us to decouple the gravitational field equations and integrate them in a very
general form with the metric and vielbein fields depending on all the spacetime
coordinates via means of various generating and integration functions and
parameters. We study how solutions in MGTs may be related to the dynamical
generation of a gravitino mass and supersymmetry breaking.


title: Regge Amplitudes for Two-to-Two Reactions

abstract:
  We present a fit based on Regge theory of two-to-two reactions at high
energies particulary focused on leading non-strange positive naturality
exchanges. Factorization of the residues is assumed between beam and target
vertices. This study is a first step toward the analysis of multiple mesons
peripherical production.


title:
On ergodic properties of nonlinear Markov chains and stochastic
  McKean-Vlasov equations

abstract:
  We study ergodic properties of nonlinear Markov chains and stochastic
McKean-Vlasov equations. For nonlinear Markov chains we obtain sufficient
conditions for existence and uniqueness of an invariant measure and uniform
ergodicity. We also prove optimality of these conditions. For stochastic
McKean-Vlasov equations we establish exponential convergence of their solutions
to stationarity in the total variation metric under
Veretennikov-Khasminskii-type conditions.


title: Angular Momentum Generation from Holographic Chern-Simons Models

abstract:
  We study parity-violating effects, particularly the generation of angular
momentum density and its relation to the parity-odd and dissipationless
transport coefficient Hall viscosity, in strongly-coupled quantum fluid systems
in 2+1 dimensions using holographic method. We employ a class of
3+1-dimensional holographic models of Einstein-Maxwell system with gauge and
gravitational Chern-Simons terms coupled to a dynamical scalar field. The
scalar can condensate and break the parity spontaneously. We find that when the
scalar condensates, a non-vanishing angular momentum density and an associated
edge current are generated, and they receive contributions from both gauge and
gravitational Chern-Simons terms. The angular momentum density does not satisfy
a membrane paradigm form because the vector mode fluctuations from which it is
calculated are effectively massive. On the other hand, the emergence of Hall
viscosity is a consequence of the gravitational Chern-Simons term alone and it
has membrane paradigm form. We present both general analytic results and
numeric results which take back-reactions into account. The ratio between Hall
viscosity and angular momentum density resulting from the gravitational
Chern-Simons term has in general a deviation from the universal 1/2 value
obtained from field theory and condensed matter physics.


title:
How fast can an unstable particle decay into two final states and be
  observed

abstract:
  We investigate unstable hadrons (resonances) which mainly decay into two
final states in a very short time. We estimate how far at most these two final
states can travel away from each other in the half-life of the initial unstable
hadron. As examples, this distance is about 2.5 fm for rho -> pi pi, 1.8 fm for
Delta -> N pi, and 0.6 fm for f_0(500) -> pi pi. We calculate this distance for
altogether 181 hadrons, among all the 324 ones listed in PDG2012 together with
Zc(3900) and Zc(4025). We find it is around one femtometer for many hadrons,
which is of the same order of magnitude as the hadronic radii. We also estimate
this distance for altogether 15 unstable nuclei. We find it is about several
femtometers for some of them, which is of the same order of magnitude as the
nuclear radii. For example, it is about six femtometers for O12 -> N11 p.


title:
Application of the Moment-SOS Approach to Global Optimization of the OPF
  Problem

abstract:
  Finding a global solution to the optimal power flow (OPF) problem is
difficult due to its nonconvexity. A convex relaxation in the form of
semidefinite programming (SDP) has attracted much attention lately as it yields
a global solution in several practical cases. However, it does not in all
cases, and such cases have been documented in recent publications. This paper
presents another SDP method known as the moment-sos (sum of squares) approach,
which generates a sequence that converges towards a global solution to the OPF
problem at the cost of higher runtime. Our finding is that in the small
examples where the previously studied SDP method fails, this approach finds the
global solution. The higher cost in runtime is due to an increase in the matrix
size of the SDP problem, which can vary from one instance to another. Numerical
experiment shows that the size is very often a quadratic function of the number
of buses in the network, whereas it is a linear function of the number of buses
in the case of the previously studied SDP method.


title: On Approximate Inference for Generalized Gaussian Process Models

abstract:
  A generalized Gaussian process model (GGPM) is a unifying framework that
encompasses many existing Gaussian process (GP) models, such as GP regression,
classification, and counting. In the GGPM framework, the observation likelihood
of the GP model is itself parameterized using the exponential family
distribution (EFD). In this paper, we consider efficient algorithms for
approximate inference on GGPMs using the general form of the EFD. A particular
GP model and its associated inference algorithms can then be formed by changing
the parameters of the EFD, thus greatly simplifying its creation for
task-specific output domains. We demonstrate the efficacy of this framework by
creating several new GP models for regressing to non-negative reals and to real
intervals. We also consider a closed-form Taylor approximation for efficient
inference on GGPMs, and elaborate on its connections with other model-specific
heuristic closed-form approximations. Finally, we present a comprehensive set
of experiments to compare approximate inference algorithms on a wide variety of
GGPMs.


title:
Analysis of block-preconditioners for models of coupled magma/mantle
  dynamics

abstract:
  This article considers the iterative solution of a finite element
discretisation of the magma dynamics equations. In simplified form, the magma
dynamics equations share some features of the Stokes equations. We therefore
formulate, analyse and numerically test a Elman, Silvester and Wathen-type
block preconditioner for magma dynamics. We prove analytically and demonstrate
numerically the optimality of the preconditioner. The presented analysis
highlights the dependence of the preconditioner on parameters in the magma
dynamics equations that can affect convergence of iterative linear solvers. The
analysis is verified through a range of two- and three-dimensional numerical
examples on unstructured grids, from simple illustrative problems through to
large problems on subduction zone-like geometries. The computer code to
reproduce all numerical examples is freely available as supporting material.


title: Well-posedness of the linearized problem for contact MHD discontinuities

abstract:
  We study the free boundary problem for contact discontinuities in ideal
compressible magnetohydrodynamics (MHD). They are characteristic
discontinuities with no flow across the discontinuity for which the pressure,
the magnetic field and the velocity are continuous whereas the density and the
entropy may have a jump. Under the Rayleigh-Taylor sign condition $[\partial
p/\partial N]<0$ on the jump of the normal derivative of the pressure satisfied
at each point of the unperturbed contact discontinuity, we prove the
well-posedness in Sobolev spaces of the linearized problem for 2D planar MHD
flows.


title: Fluctuations in strongly coupled cosmologies

abstract:
  In the early Universe, a dual component made of coupled CDM and a scalar
field $\Phi$, if their coupling $\beta > \sqrt{3}/2$, owns an attractor
solution, making them a stationary fraction of cosmic energy during the
radiation dominated era. Along the attractor, both such components expand
$\propto a^{-4}$ and have early density parameters $\Omega_{d} = 1/ (4\beta^2)$
and $\Omega_c= 2, \Omega_d$ (field and CDM, respectively). In a previous paper
it was shown that, if a further component, expanding $\propto a^{-3}$, breaks
such stationary expansion at $z \sim 3$--$5 \times 10^3$, cosmic components
gradually acquire densities consistent with observations. This paper, first of
all, considers the case that this component is warm. However, its main topic is
the analysis of fluctuation evolution: out of horizon modes are then
determined; their entry into horizon is numerically evaluated as well as the
dependence of Meszaros effect on the coupling $\beta$; finally, we compute: (i)
transfer function and linear spectral function; (ii) CMB $C_l$ spectra. Both
are close to standard $\Lambda$CDM models; in particular, the former one can be
so down to a scale smaller than Milky Way, in spite of its main DM component
being made of particles of mass $<1$ keV. The previously coupled CDM component,
whose present density parameter is $\cal O$$(10^{-3})$, exhibits wider
fluctuations $\delta \rho/\rho$, but approximately $\beta$-independent $\delta
\rho$ values. We discuss how lower scale features of these cosmologies might
ease quite a few problems that $\Lambda$CDM does not easily solve.


title: On Non-Standard Models of Peano Arithmetic and Tennenbaum's Theorem

abstract:
  Throughout the course of mathematical history, generalizations of previously
understood concepts and structures have led to the fruitful development of the
hierarchy of number systems, non-euclidean geometry, and many other epochal
phases in mathematical progress. In the study of formalized theories of
arithmetic, it is only natural to consider the extension from the standard
model of Peano arithmetic, $\langle \mathbb{N},+,\times,\leq,0,1 \rangle$, to
non-standard models of arithmetic. The existence of non-standard models of
Peano arithmetic provided motivation in the early $20^{th}$ century for a
variety of questions in model theory regarding the classification of models up
to isomorphism and the properties that non-standard models of Peano arithmetic
have. This paper presents these questions and the necessary results to prove
Tennenbaum's Theorem, which draws an explicit line between the properties of
standard and non-standard models; namely, that no countable non-standard model
of Peano arithmetic is recursive. These model-theoretic results have
contributed to the foundational framework within which research programs
developed by Skolem, Rosser, Tarski, Mostowski and others have flourished.
While such foundational topics were crucial to active fields of research during
the middle of the $20^{th}$ century, numerous open questions about models of
arithmetic, and model theory in general, still remain pertinent to the realm of
$21^{st}$ century mathematical discourse.


title: Bayesian Analysis of Epidemics - Zombies, Influenza, and other Diseases

abstract:
  Mathematical models of epidemic dynamics offer significant insight into
predicting and controlling infectious diseases. The dynamics of a disease model
generally follow a susceptible, infected, and recovered (SIR) model, with some
standard modifications. In this paper, we extend the work of Munz et.al (2009)
on the application of disease dynamics to the so-called "zombie apocalypse",
and then apply the identical methods to influenza dynamics. Unlike Munz et.al
(2009), we include data taken from specific depictions of zombies in popular
culture films and apply Markov Chain Monte Carlo (MCMC) methods on improved
dynamical representations of the system. To demonstrate the usefulness of this
approach, beyond the entertaining example, we apply the identical methodology
to Google Trend data on influenza to establish infection and recovery rates.
Finally, we discuss the use of the methods to explore hypothetical intervention
policies regarding disease outbreaks.


title: Emission of Cherenkov Radiation as a Mechanism for Hamiltonian Friction

abstract:
  We study the motion of a heavy tracer particle weakly coupled to a dense,
weakly interacting Bose gas exhibiting Bose-Einstein condensation. In the
so-called mean-field limit, the dynamics of this system approaches one
determined by nonlinear Hamiltonian evolution equations. We prove that if the
initial speed of the tracer particle is above the speed of sound in the Bose
gas, and for a suitable class of initial states of the Bose gas, the particle
decelerates due to emission of Cherenkov radiation of sound waves, and its
motion approaches a uniform motion at the speed of sound, as time tends to
infinity.


title:
Clifford Algebra and Space-Time Transformations: Lorentz Transformation
  and Inertial Transformation

abstract:
  We review the Inertial transformation and Lorentz transformation under a new
context, by using Clifford Algebra or Geometric Algebra. The apparent
contradiction between theses two approach is simply stems from different
procedures for clock synchronization associated with different choices of the
coordinates used to describe the physical world. We find the physical and
coordinates components of both transformations. A important result is that in
the case of Inertial transformation the physical components are exactly the
Galilean transformations, but the speed of light is not c. Another interesting
result is due to the fact the Lorentz transformations lead directly to physical
components, and this case the speed of light is c. Finally e show that both
scenarios, de-synchronization Einstein theory and synchronized theory, are all
mathematically equivalent by means of Clifford Algebra Transformations.


title:
A fast and scalable kymograph alignment algorithm for nanochannel-based
  optical DNA mappings

abstract:
  Optical mapping by direct visualization of individual DNA molecules,
stretched in nanochannels with sequence-specific fluorescent labeling,
represents a promising tool for disease diagnostics and genomics. An important
challenge for this technique is thermal motion of the DNA as it undergoes
imaging; this blurs fluorescent patterns along the DNA and results in
information loss. Correcting for this effect (a process referred to as
kymograph alignment) is a common preprocessing step in nanochannel-based
optical mapping workflows, and we present here a highly efficient algorithm to
accomplish this via pattern recognition. We compare our method with the one
previous approach, and we find that our method is orders of magnitude faster
while producing data of similar quality. We demonstrate proof of principle of
our approach on experimental data consisting of melt mapped bacteriophage DNA.


title:
muSR and inelastic neutron scattering investigations of the caged type
  Kondo semimetals: CeT2Al10 (T=Fe, Ru and Os)

abstract:
  Recently the Ce-based caged-type compounds having general formula CeT2Al10
(T=Fe, Ru and Os) have generated considerable interest due to the Kondo
semiconducting paramagnetic ground state (down to 40 mK) observed in CeFe2Al10
and anomalously high magnetic ordering temperature with a spin gap formation at
low temperatures in Kondo semimetals CeRu2Al10 and CeOs2Al10. The formation of
long-range magnetic ordering out of the Kondo semiconducting/semimetallic state
itself is extraordinary and these are the first examples of this enigmatic
coexistence of electronic ground states. These compounds also exhibit strong
anisotropy in the magnetic and transport properties, which has been explained
on the basis of single ion crystal electric field (CEF) anisotropy in the
presence of strongly anisotropic hybridization between localised 4f-electron
and conduction electrons. Further they also exhibit a remarkable modification
of magnetic and transport properties with doping on Ce, or T or Al sites. In
this review we briefly discuss the bulk properties of these compounds, giving a
detailed discussion on our muon-spin-relaxation (muSR) investigations and
inelastic neutron scattering (INS) results.


title:
The local nature of incompressibility at quantised Hall effect modified
  by interactions

abstract:
  Since the experimental realisation of the integer quantised Hall effect in a
two dimensional electron system subject to strong perpendicular magnetic fields
in 1980, a central question has been the interrelation between the conductance
quantisation and the topological properties of the system. It is conjectured
that if the electron system is described by a Bloch hamiltonian, then the
system is insulating in the bulk of the sample throughout the quantised Hall
plateau due to magnetic field induced energy gap. Meanwhile, the system is
conducting at the edges resembling a 2+1 dimensional topological insulator
without the time-reversal symmetry. However, the validity of this conjecture
remains unclear for finite size, non-periodically bounded real Hall bar
devices. Here we show experimentally that the close relationship proposed
between the quantised Hall effect and the topological bulk insulator is prone
to break for specific magnetic field intervals within the plateau evidenced by
our magneto-transport measurements performed on GaAs/AlGaAs high purity Hall
bars with two inner contacts embedded to bulk. Our data presents a similar
behaviour also for fractional states, in particular for 2/3, 3/5 and 4/3.


title: Inverted-wedge silica resonators for controlled and stable coupling

abstract:
  Silica microresonators with an inverted-wedge shape were fabricated using
conventional semiconductor fabrication methods. The measured quality factors of
the resonators were greater than $10^6$ in 1550 nm band. Controllable coupling
from under coupling, through critical coupling, to over coupling was
demonstrated by horizontally moving a fiber taper while in touch with the top
surface of the resonator. Thin outer ring of the resonator provided a support
for the fiber taper leading to a robust stable coupling.


title: Magnification bias as a novel probe for primordial magnetic fields

abstract:
  In this paper we investigate magnetic fields generated in the early Universe.
These fields are important candidates at explaining the origin of astrophysical
magnetism observed in galaxies and galaxy clusters, whose genesis is still by
and large unclear. Compared to the standard inflationary power spectrum,
intermediate to small scales would experience further substantial matter
clustering, were a cosmological magnetic field present prior to recombination.
As a consequence, the bias and redshift distribution of galaxies would also be
modified. Hitherto, primordial magnetic fields (PMFs) have been tested and
constrained with a number of cosmological observables, e.g. the cosmic
microwave background radiation, galaxy clustering and, more recently, weak
gravitational lensing. Here, we explore the constraining potential of the
density fluctuation bias induced by gravitational lensing magnification onto
the galaxy-galaxy angular power spectrum. Such an effect is known as
magnification bias. Compared to the usual galaxy clustering approach,
magnification bias helps in lifting the pathological degeneracy present amongst
power spectrum normalisation and galaxy bias. This is because magnification
bias cross-correlates galaxy number density fluctuations of nearby objects with
weak lensing distortions of high-redshift sources. Thus, it takes advantage of
the gravitational deflection of light, which is insensitive to galaxy bias but
powerful in constraining the density fluctuation amplitude. To scrutinise the
potentiality of this method, we adopt a deep and wide-field spectroscopic
galaxy survey. We show that magnification bias does contain important
information on primordial magnetism, which will be useful in combination with
galaxy clustering and shear. We find we shall be able to rule out at 95.4% CL
amplitudes of PMFs larger than 0.0005 nG for values of the PMF power spectral
index ~0.


title:
Elliptic solutions of generalized Brans-Dicke gravity with a
  non-universal coupling

abstract:
  We study a model of the generalized Brans-Dicke gravity presented in both the
Jordan and in the Einstein frames, which are conformally related. We show that
the scalar field equations in the Einstein frame are reduced to the geodesics
equations on the target space of the nonlinear sigma-model. The analytical
solutions in elliptical functions are obtained when the conformal couplings are
given by reciprocal exponential functions. The behavior of the scale factor in
the Jordan frame is studied using numerical computations. For certain
parameters the solutions can describe an accelerated expansion. We also derive
an analytical approximation in exponential functions.


title:
Crucial effect of glass processing and melt homogenization on the
  fragility of non-stoichiometric chalcogenides

abstract:
  The kinetics of homogenization of binary As$_x$Se$_{100-x}$ melts in the As
concentration range $0\%$ $<$ $x$ $<$ $50\%$ are followed in FT-Raman profiling
experiments, and show that 2 gram sized melts in the middle concentration range
$20\%$ $<$ $x$ $<$ $30\%$ take nearly two weeks to homogenize when starting
materials are reacted at 700$^o$C. In glasses of proven homogeneity, we find
molar volumes to vary non-monotonically with composition, and the fragility
index ${\cal M}$ displays a broad global minimum in the $20\%$ $<$ $x$ $<$
$30\%$ range of $x$ wherein ${\cal M}<$ 20. We show that properly homogenized
samples have a lower measured fragility when compared to larger under-reacted
melts. The enthalpy of relaxation at T$_g$, $\Delta$H$_{nr}$($x$) shows a
minimum in the $27\%$ $<$ $x$ $<$ $37\%$ range. The super-strong nature of melt
compositions in the $20\%$ $<$ $x$ $<$ $30\%$ range suppresses melt diffusion
at high temperatures leading to the slow kinetics of melt homogenization.


title: Direct detection of dark matter in universal bound states

abstract:
  We study the signatures for internal structure of dark matter in direct
detection experiments in the context of asymmetric self-interacting dark
matter. The self-interaction cross section of two dark matter particles at low
energies is assumed to come close to saturating the S-wave unitarity bound,
which requires the presence of a resonance near their scattering threshold. The
universality of S-wave near-threshold resonances then implies that the
low-energy scattering properties of a two-body bound state of dark matter
particles are completely determined by its binding energy, irrespective of the
underlying microphysics. The form factor for elastic scattering of the bound
state from a nucleus and the possibility of breakup of the bound state produce
new signatures in the nuclear recoil energy spectrum. If these features are
observed in experiments, it will give a smoking-gun signature for the internal
structure of dark matter.


title: Effective Ratner theorem for ASL(2,R) and gaps in \sqrt{n} modulo 1

abstract:
  Let G=ASL(2,R) be the affine special linear group of the plane, and set
Gamma=ASL(2,Z). Building on recent work of Str\"ombergsson we prove a rate of
equidistribution for the orbits of a certain 1-dimensional unipotent flow of
Gamma\G, which projects to a closed horocycle in the unit tangent bundle to the
modular surface. We use this to answer a question of Elkies and McMullen by
making effective the convergence of the gap distribution of \sqrt{n} modulo 1.


title:
Max-Min SNR Signal Energy based Spectrum Sensing Algorithms for
  Cognitive Radio Networks with Noise Variance Uncertainty

abstract:
  This paper proposes novel spectrum sensing algorithms for cognitive radio
networks. By assuming known transmitter pulse shaping filter, synchronous and
asynchronous receiver scenarios have been considered. For each of these
scenarios, the proposed algorithm is explained as follows: First, by
introducing a combiner vector, an over-sampled signal of total duration equal
to the symbol period is combined linearly. Second, for this combined signal,
the Signal-to-Noise ratio (SNR) maximization and minimization problems are
formulated as Rayleigh quotient optimization problems. Third, by using the
solutions of these problems, the ratio of the signal energy corresponding to
the maximum and minimum SNRs are proposed as a test statistics. For this test
statistics, analytical probability of false alarm ($P_f$) and detection ($P_d$)
expressions are derived for additive white Gaussian noise (AWGN) channel. The
proposed algorithms are robust against noise variance uncertainty. The
generalization of the proposed algorithms for unknown transmitter pulse shaping
filter has also been discussed. Simulation results demonstrate that the
proposed algorithms achieve better $P_d$ than that of the Eigenvalue
decomposition and energy detection algorithms in AWGN and Rayleigh fading
channels with noise variance uncertainty. The proposed algorithms also
guarantee the desired $P_f(P_d)$ in the presence of adjacent channel
interference signals.


title:
On the interpolation property and dominated decomposition property of
  quasimartingales

abstract:
  For a quasimartingale majorized by another quasimartingale, it is natural to
ask whether a third quasimartingale can be inserted between them. In this
paper, we give an affirmative answer to this problem. We also establish a
dominated decomposition property of quasimartingales. In addition, we show that
a weak interpolation property holds for supermartingales and local
supermartingales. Our approach also yields the interpolation property and
dominated decomposition property for Markov chains.


title:
Terahertz Multiparameter Sensor using Fiber-Interrogated Frequency
  Selective Surface

abstract:
  We propose using THz frequency selective surfaces interrogated with THz
subwavelength optical fibers as sensors for monitoring of the optical
properties of thick films that are brought in contact with such surfaces.
Changes in the test film thickness and absorption losses can be measured
simultaneously by interpreting variations in the spectral resonant features in
the fiber transmission and reflection spectra. Particularly, changes in the
film thickness induce strong shifts in the fiber transmission peaks, while
changes in the film absorption induce notable amplitude variations in the fiber
reflection peaks. When applied to the problem of monitoring of thickness and
humidity content in the paper sheets, the proposed system shows sensitivity of
1.5 GHz / 10 um to changes in the paper thickness, and sensitivity of 0.6 / (%
of water by volume) to changes in the paper humidity. We estimate the detection
limit of our device to be 10 um for the paper thickness variation and 0.02% (of
water by volume) for the paper humidity variation. Proposed sensor is
implemented in the spirit of integrated optics, where a point device based on
the frequency selective surface is interrogated with a THz fiber that is used
for remote delivery of THz radiation.


title:
Study of Critical Dynamics in Fluid via Molecular Dynamics in Canonical
  Ensemble

abstract:
  With the objective of demonstrating usefulness of thermostats in the study of
dynamic critical phenomena in fluids, we present results for transport
properties in a binary Lennard-Jones fluid that exhibits liquid-liquid phase
transition. Results from the molecular dynamics simulations in canonical
ensemble, with various thermostats, are compared with those from microcanonical
ensemble. It is observed that the Nos\'{e}-Hoover and dissipative particle
dynamics thermostats are useful for the calculations of mutual diffusivity and
shear viscosity. The Nos\'{e}-Hoover thermostat, however, appears inadequate
for the study of bulk viscosity.


title:
A Comprehensive Approach to Universal Piecewise Nonlinear Regression
  Based on Trees

abstract:
  In this paper, we investigate adaptive nonlinear regression and introduce
tree based piecewise linear regression algorithms that are highly efficient and
provide significantly improved performance with guaranteed upper bounds in an
individual sequence manner. We use a tree notion in order to partition the
space of regressors in a nested structure. The introduced algorithms adapt not
only their regression functions but also the complete tree structure while
achieving the performance of the "best" linear mixture of a doubly exponential
number of partitions, with a computational complexity only polynomial in the
number of nodes of the tree. While constructing these algorithms, we also avoid
using any artificial "weighting" of models (with highly data dependent
parameters) and, instead, directly minimize the final regression error, which
is the ultimate performance goal. The introduced methods are generic such that
they can readily incorporate different tree construction methods such as random
trees in their framework and can use different regressor or partitioning
functions as demonstrated in the paper.


title: A loop group extension of the odd Chern character

abstract:
  We show that the universal odd Chern form, defined on the stable unitary
group $U$, extends to the loop group $LU$ in a way that is closed with respect
to an equivariant-type differential. This provides an odd analogue to the
Bismut-Chern form. We also describe the associated transgression form, the
so-called Bismut-Chern-Simons form, and explicate some properties it inherits
as a differential form on the space of maps of a cylinder into the stable
unitary group. As a corollary, we obtain the Chern character homomorphism from
odd K-theory to the periodic cohomology of the free loop space, represented
geometrically on the level of differential forms.


title: The homotopy theory of diffeological spaces

abstract:
  Diffeological spaces are generalizations of smooth manifolds. In this paper,
we study the homotopy theory of diffeological spaces. We begin by proving basic
properties of the smooth homotopy groups that we will need later. Then we
introduce the smooth singular simplicial set $S^D(X)$ associated to a
diffeological space $X$, and show that when $S^D(X)$ is fibrant, it captures
smooth homotopical properties of $X$. Motivated by this, we define $X$ to be
fibrant when $S^D(X)$ is, and more generally define cofibrations, fibrations
and weak equivalences in the category of diffeological spaces using the smooth
singular simplicial set functor. We conjecture that these form a model category
structure, but in this paper we assume little prior knowledge of model
categories, and instead focus on concrete questions about smooth manifolds and
diffeological spaces. We prove that our setup generalizes the naive smooth
homotopy theory of smooth manifolds by showing that a smooth manifold without
boundary is fibrant and that for fibrant diffeological spaces, the weak
equivalences can be detected using ordinary smooth homotopy groups. We also
show that our definition of fibrations generalizes Iglesias-Zemmour's theory of
diffeological bundles. We prove enough of the model category axioms to show
that every diffeological space has a functorial cofibrant replacement. We give
many explicit examples of objects that are cofibrant, not cofibrant, fibrant
and not fibrant, as well as many other examples showing the richness of the
theory. For example, we show that the free loop space of a smooth manifold is
fibrant. One of the implicit points of this paper is that the language of model
categories is an effective way to organize homotopical thinking, even when it
is not known that all of the model category axioms are satisfied.


title:
Integral Invariance and Non-linearity Reduction for Proliferating
  Vorticity Scales in Fluid Dynamics

abstract:
  An effort has been made to solve the Cauchy problem of the Navier-Stokes
equations in the whole space by two methods. It is proved that the sum of the
three vorticity components is a time-invariant in fluid motion. It has been
proved that, given smooth, localized initial data with finite energy and
enstrophy, the vorticity equation admits a global, unique and smooth solution.
Second, the vorticity equation has been converted into a non-linear integral
equation by means of similarity reduction. The solution of the integral
equation has been constructed in a series expansion. The series is shown to
converge for initial data of finite size. The complete vorticity field is
characterized, as an instantaneous description, by a multitude of vorticity
constituents. The flow field is composed of vortical elements of broad
spatio-temporal scales. Inference of the solutions leads itself to a
satisfactory account for the observed dynamic characteristics of transition
process, and of turbulent motion. In the limit of vanishing viscosity, the
equations of motion cannot develop flow-field singularities in finite time. In
the Maxwell-Boltzmann kinetic theory, the density function of the Maxwellian
molecules possesses a phase-space distribution resembling the continuum
turbulence. Qualitatively, the apparent macroscopic randomness of turbulence
can be attributed to a ramification of molecular fluctuations.


title:
A Unified Approach to Universal Prediction: Generalized Upper and Lower
  Bounds

abstract:
  We study sequential prediction of real-valued, arbitrary and unknown
sequences under the squared error loss as well as the best parametric predictor
out of a large, continuous class of predictors. Inspired by recent results from
computational learning theory, we refrain from any statistical assumptions and
define the performance with respect to the class of general parametric
predictors. In particular, we present generic lower and upper bounds on this
relative performance by transforming the prediction task into a parameter
learning problem. We first introduce the lower bounds on this relative
performance in the mixture of experts framework, where we show that for any
sequential algorithm, there always exists a sequence for which the performance
of the sequential algorithm is lower bounded by zero. We then introduce a
sequential learning algorithm to predict such arbitrary and unknown sequences,
and calculate upper bounds on its total squared prediction error for every
bounded sequence. We further show that in some scenarios we achieve matching
lower and upper bounds demonstrating that our algorithms are optimal in a
strong minimax sense such that their performances cannot be improved further.
As an interesting result we also prove that for the worst case scenario, the
performance of randomized algorithms can be achieved by sequential algorithms
so that randomized algorithms does not improve the performance.


title:
Stability issues in the quasineutral limit of the one-dimensional
  Vlasov-Poisson equation

abstract:
  This work is concerned with the quasineutral limit of the one-dimensional
Vlasov-Poisson equation, for initial data close to stationary homogeneous
profiles. Our objective is threefold: first, we provide a proof of the fact
that the formal limit does not hold for homogeneous profiles that satisfy the
Penrose instability criterion. Second, we prove on the other hand that the
limit is true for homogeneous profiles that satisfy some monotonicity
condition, together with a symmetry condition. We handle the case of
well-prepared as well as ill- prepared data. Last, we study a stationary
boundary-value problem for the formal limit, the so-called quasineutral Vlasov
equation. We show the existence of numerous stationary states, with a lot of
freedom in the construction (compared to that of BGK waves for Vlasov-Poisson):
this illustrates the degeneracy of the limit equation.


title:
A2: Mathematical relativity and other progress in classical gravity
  theory - a session report

abstract:
  We report on selected oral contributions to the A2 session "Mathematical
relativity and other progress in classical gravity theory" of "The 20th
International Conference on General Relativity and Gravitation (GR20)" in
Warsaw.


title:
On asymptotic effects of boundary perturbations in exponentially shaped
  Josephson junctions

abstract:
  A parabolic integro differential operator L, suitable to describe many
phenomena in various physical fields, is considered. By means of equivalence
between L and the third order equation describing the evolution inside an
exponentially shaped Josephson junction (ESJJ), an asymptotic analysis for
(ESJJ) is achieved, explicitly evaluating, boundary contributions related to
the Dirichlet problem.


title: Limitations of estimating turbulent convection velocities from PIV

abstract:
  This paper deals with determination of turbulent convection velocities from
particle image velocimetry (PIV). Turbulent convection velocities are of
interest because they can be used to map temporal information into space.
Convection velocity can be defined in several different ways. One approach is
to use the phase-spectrum of two signals with a time-separation. Obtaining
convection velocity per wavenumber involves determining a spatial spectrum. PIV
data is limited in spatial resolution and sample length. The influence of
truncation of both spatial resolution and frequency resolution is investigated,
as well as the influences of spatial filtering and measurement noise. These
issues are investigated by using a synthetic data set obtained by creating
velocity-time data with an imposed spectrum. Results from the validation show
that, when applying a Hamming window before determining the phase spectrum,
there is a usable range of wavenumbers for which convection velocities can be
determined. Simulation of flow evolution, movement into and out of the
measurement plane, and measurement noise show that these result in a spread in
convection velocities using the current approach. Despite this spread, the most
probable calculated convection velocity coincides with the imposed convection
velocity. Application of the phase-spectral approach to a turbulent boundary
layer with $Re_\tau \approx 2700$, shows there is a range of convection
velocities and that the most probable convection velocity is equal to the local
mean velocity.


title:
A model for generating tunable clustering coefficients independent of
  the number of nodes in scale free and random networks

abstract:
  Probabilistic networks display a wide range of high average clustering
coefficients independent of the number of nodes in the network. In particular,
the local clustering coefficient decreases with the degree of the subtending
node in a complicated manner not explained by any current models. While a
number of hypotheses have been proposed to explain some of these observed
properties, there are no solvable models that explain them all. We propose a
novel growth model for both random and scale free networks that is capable of
predicting both tunable clustering coefficients independent of the network
size, and the inverse relationship between the local clustering coefficient and
node degree observed in most networks.


title: Robust Least Squares Methods Under Bounded Data Uncertainties

abstract:
  We study the problem of estimating an unknown deterministic signal that is
observed through an unknown deterministic data matrix under additive noise. In
particular, we present a minimax optimization framework to the least squares
problems, where the estimator has imperfect data matrix and output vector
information. We define the performance of an estimator relative to the
performance of the optimal least squares (LS) estimator tuned to the underlying
unknown data matrix and output vector, which is defined as the regret of the
estimator. We then introduce an efficient robust LS estimation approach that
minimizes this regret for the worst possible data matrix and output vector,
where we refrain from any structural assumptions on the data. We demonstrate
that minimizing this worst-case regret can be cast as a semi-definite
programming (SDP) problem. We then consider the regularized and structured LS
problems and present novel robust estimation methods by demonstrating that
these problems can also be cast as SDP problems. We illustrate the merits of
the proposed algorithms with respect to the well-known alternatives in the
literature through our simulations.


title:
Maximum-Likelihood Estimation of a Log-Concave Density based on Censored
  Data

abstract:
  We consider nonparametric maximum-likelihood estimation of a log-concave
density in case of interval-censored, right-censored and binned data. We allow
for the possibility of a subprobability density with an additional mass at
$+\infty$, which is estimated simultaneously. The existence of the estimator is
proved under mild conditions and various theoretical aspects are given, such as
certain shape and consistency properties. An EM algorithm is proposed for the
approximate computation of the estimator and its performance is illustrated in
two examples.


title: Tailoring Non-Compact Spin Chains

abstract:
  We study three-point correlation functions of local operators in planar
$\mathcal{N}=4$ SYM at weak coupling using integrability. We consider
correlation functions involving two scalar BPS operators and an operator with
spin, in the so called SL(2) sector. At tree level we derive the corresponding
structure constant for any such operator. We also conjecture its one loop
correction. To check our proposals we analyze the conformal partial wave
decomposition of known four-point correlation functions of BPS operators. In
perturbation theory, we extract from this decomposition sums of structure
constants involving all primaries of a given spin and twist. On the other hand,
in our integrable setup these sum rules are computed by summing over all
solutions to the Bethe equations. A perfect match is found between the two
approaches.


title:
The Play Operator, the Truncated Variation and the Generalisation of the
  Jordan Decomposition

abstract:
  The play operator minimalizes the total variation on intervals $[0,T], T> 0$,
of functions approximating uniformly given regulated function with given
accuracy and starting from a given point. In this article we link the play
operator with so called truncated variation functionals, introduced recently by
the second-named author, and provide a semi-explicit expression for the play
operator in terms of these functionals. Generalisation for time-dependent
boundaries is also considered. This gives the best possible lower bounds for
the total variation of the outputs of the play operator and its Jordan-like
decomposition.


title:
Simultaneous optogenetic manipulation and calcium imaging in freely
  moving C. elegans

abstract:
  A fundamental goal of systems neuroscience is to probe the dynamics of neural
activity that drive behavior. Here we present an instrument to simultaneously
manipulate neural activity via Channelrhodopsin, monitor neural response via
GCaMP3, and observe behavior in freely moving C. elegans. We use the instrument
to directly observe the relation between sensory stimuli, interneuron activity
and locomotion in the mechanosensory circuit.


title:
Gadolinium in water Cherenkov detectors improves detection of supernova
  $\nu_e$

abstract:
  Detecting supernova $\nu_e$ is essential for testing supernova and neutrino
physics, but the yields are small and the backgrounds from other channels
large, e.g., $\sim 10^2$ and $\sim 10^4$ events, respectively, in
Super-Kamiokande. We develop a new way to isolate supernova $\nu_e$, using
gadolinium-loaded water Cherenkov detectors. The forward-peaked nature of
$\nu_e + e^- \rightarrow \nu_e + e^-$ allows an angular cut that contains the
majority of events. Even in a narrow cone, near-isotropic inverse beta events,
$\bar{\nu}_e + p \rightarrow e^+ + n$, are a large background. With neutron
detection by radiative capture on gadolinium, the background events can be
individually identified with high efficiency. The remaining backgrounds are
smaller and can be measured separately, so they can be statistically
subtracted. Super-Kamiokande with gadolinium could measure the total and
average energy of supernova $\nu_e$ with $\sim$ $20\%$ precision or better each
($90\%$ C.L.). Hyper-Kamiokande with gadolinium could improve this by a factor
of $\sim$ 5. This precision will allow powerful tests of supernova neutrino
emission, neutrino mixing, and exotic physics. Unless very large liquid argon
or liquid scintillator detectors are built, this is the only way to guarantee
precise measurements of supernova $\nu_e$.


title:
The nature of supernovae 2010O and 2010P in Arp 299 - I. Near-infrared
  and optical evolution

abstract:
  We present near-infrared and optical photometry, plus optical spectroscopy of
two stripped-envelope supernovae (SNe) 2010O and 2010P that exploded in two
different components of an interacting luminous infrared galaxy Arp 299 within
only a few days of one another. SN 2010O is found to be photometrically and
spectroscopically similar to many normal Type Ib SNe and our multiwavelength
observations of SN 2010P suggest it to be a Type IIb SN. No signs of clear
hydrogen features or interaction with the circumstellar medium are evident in
the optical spectrum of SN 2010P. We derive estimates for the host galaxy
line-of-sight extinctions for both SNe, based on both light-curve and
spectroscopic comparison finding consistent results. These methods are also
found to provide much more robust estimates of the SN host galaxy reddening
than the commonly used empirical relations between extinction and equivalent
width of Na I D absorption features. The SN observations also suggest that
different extinction laws are present in different components of Arp 299. For
completeness, we study high-resolution pre-explosion images of Arp 299 and find
both SNe to be close to, but not coincident with, extended sources that are
likely massive clusters. A very simple model applied to the bolometric light
curve of SN 2010O implies a rough estimate for the explosion parameters of
$E_{\mathrm{k}} \approx 3 \times 10^{51}$ erg, $M_{\mathrm{ej}} \approx 2.9$
M$_{\odot}$ and $M_{\mathrm{Ni}} \approx 0.16$ M$_{\odot}$.


title:
Gravitino and other spin-3/2 quasinormal modes in Schwarzschild-AdS
  spacetime

abstract:
  We investigate quasinormal mode frequencies $\omega_n$ of gravitinos and
generic massive spin-3/2 fields in a Schwarzschild-AdS$_D$ background in
spacetime dimension $D>3$, in the black brane (large black hole) limit
appropriate to many applications of the AdS/CFT correspondence. First, we find
asymptotic formulas for $\omega_n$ in the limit of large overtone number $n$.
Asymptotically, $\omega_n \simeq n \Delta\omega + O(\ln n) + O(n^0)$, where
$\Delta\omega$ is a known constant, and here we compute the $O(\ln n)$ and
$O(n^0)$ corrections to the leading $O(n)$ behavior. Then we compare to
numerical calculations of exact quasinormal mode frequencies. Along the way, we
also improve the reach and accuracy of an earlier, similar analysis of spin-1/2
fields.


title:
Theory of nodal s+- wave pairing symmetry in the Pu-based 115
  superconductor family

abstract:
  The spin-fluctuation mechanism of superconductivity usually results in the
presence of gapless or nodal quasiparticle states in the excitation spectrum.
Nodal quasiparticle states are well established in copper-oxide, and
heavy-fermion superconductors, but not in iron-based superconductors. Here, we
study the pairing symmetry and mechanism of a new class of plutonium-based
high-Tc superconductors and predict the presence of a nodal $s^{+-}$ wave
pairing symmetry in this family. Starting from a density-functional theory
(DFT) based electronic structure calculation we predict several
three-dimensional (3D) Fermi surfaces in this 115 superconductor family. We
identify the dominant Fermi surface ``hot-spots' in the inter-band scattering
channel, which are aligned along the wavevector ${\bf Q}\sim(\pi,\pi,\pi)$,
where degeneracy could induce sign-reversal of the pairing symmetry. Our
calculation demonstrates that the $s^{+-}$ wave pairing strength is stronger
than the previously thought $d$-wave pairing; and more importantly, this
pairing state allows for the existence of nodal quasiparticles. Finally, we
predict the shape of the momentum- and energy-dependent magnetic resonance
spectrum for the identification of this pairing symmetry.


title: Y(3940) as a Mixed Charmonium-Molecule State

abstract:
  Using the QCD sum rules approach we study the mass and decay width of the
channel $J/\psi + \omega$ for the $Y(3940)$ state. We assume that it can be
described by a mixed charmonium-molecule scalar state, $(\chi_{c0})-(D^\ast
D^\ast)$ current, with $J^{PC} = 0^{++}$ quantum numbers. For the mixing angle
$(76.0 \pm 5.0)^0$, we obtain the value $M = (3.95 \pm 0.11)$ GeV for the mass,
which is in good agreement with the experimental mass of the $Y(3940)$ state.
For the decay width into the channel $Y \rightarrow J/\psi + \omega$, we find
the value $\Gamma_Y = (1.7 \pm 0.6)$ MeV, which is also compatible with the
experimental data. We thus conclude that the present description of the
$Y(3940)$ as a mixed charmonium-molecule state is a possible scenario to
explain the structure of this state.


title: Collective dynamics of the p-Pb collisions at the LHC

abstract:
  We review the signatures for the soft collective dynamics in
highest-multiplicity ultrarelativistic p-Pb collisions and show that the
effects are well described in a three-stage model, consisting of the
event-by-event Glauber initial conditions, viscous 3+1D hydrodynamics, and
statistical hadronization. In particular, we discuss the ridges in two-particle
correlations in the relative azimuth and pseudorapidity, the elliptic and
triangular flow coefficients, and the mass hierarchy of observables sensitive
to flow.


title:
Reduced Differential Transform Method for Solving Foam Drainage
  Equation(FDE)

abstract:
  Reduced Differental Transform Method (RDTM) which is one of the useful and
effective numerical approximate method is applied to solve nonlinear
time-dependent Foam Drainage Equation (FDE). Also, we compared the presented
method with the famous Adomian Decomposition and Laplace Decomposition
Technique. So, the results of giving examples demonstrated that RDTM is a
powerful tool for solving nonlinear PDE, it can be applied very easily and it
has less computational work than other existing methods like Adomian
decomposition and Laplace decomposition.


title: Li depletion in solar analogues with exoplanets: Extending the sample

abstract:
  We want to study the effects of the formation of planets and planetary
systems on the atmospheric Li abundance of planet host stars. In this work we
present new determinations of lithium abundances for 326 Main Sequence stars
with and without planets in the T$_\mathrm{eff}$ range 5600-5900 K. 277 stars
come from the HARPS sample, the remaining targets have been observed with a
variety of high resolution spectrographs. We confirm significant differences in
the Li distribution of solar twins (T$_\mathrm{eff}$ = T$_{\odot} \pm$ 80 K,
log g = log g$_{\odot}$ $\pm$ 0.2 and [Fe/H] = [Fe/H]$_{\odot} \pm$ 0.2): the
full sample of planet host stars (22) shows Li average values lower than
"single" stars with no detected planets (60). If we focus in subsamples with
narrower ranges in metallicity and age, we observe indications of a similar
result though it is not so clear for some of the studied subsamples.
Furthermore, we compare the observed spectra of several couples of stars with
very similar parameters which show different Li abundances up to 1.6 dex.
Therefore we show that neither age, nor mass nor metallicity of a parent star
is the only responsible for enhanced Li depletion in solar analogues. We
conclude that another variable must account for that difference and suggest
that this could be the presence of planets which causes additional rotationally
induced mixing in the external layers of planet host stars. Moreover, we find
indications that the amount of depletion of Li in planet host solar-type stars
is higher when the planets are more massive than Jupiter.


title: Hidden Photons in Extra Dimensions

abstract:
  Additional U(1) gauge symmetries and corresponding vector bosons, called
hidden photons, interacting with the regular photon via kinetic mixing are well
motivated in extensions of the Standard Model. Such extensions often exhibit
extra spatial dimensions. In this note we investigate the effects of hidden
photons living in extra dimensions. In four dimensions such a hidden photon is
only detectable if it has a mass or if there exists additional matter charged
under it. We note that in extra dimensions suitable masses for hidden photons
are automatically present in form of the Kaluza-Klein tower.


title:
An analytic proof of the Malgrange-Sibuya theorem on the convergence of
  formal solutions of an ODE

abstract:
  We propose an analytic proof of the Malgrange-Sibuya theorem concerning a
sufficient condition of the convergence of a formal power series satisfying an
ordinary differential equation. The proof is based on the majorant method and
allows to estimate the radius of convergence of such a series.


title: Viscous hyperstabilization of detonation waves in one space dimension

abstract:
  It has long been a standard practice to neglect diffusive effects in
stability analyses of detonation waves. Here, with the principal aim of
quantifying the impact of these oft-neglected effects on the stability
characteristics of such waves, we use numerical Evans-function techniques to
study the (spectral) stability of viscous strong detonation waves---particular
traveling-wave solutions of the Navier-Stokes equations modeling a mixture of
reacting gases. Remarkably, our results show a surprising synergy between the
high-activation-energy limit typically studied in stability analyses of
detonation waves and the presence of small but nonzero diffusive effects. While
our calculations do show a modest delay in the onset of instability in
agreement with recently reported calculations by direct numerical simulation of
the physical equations, our approach, based on the Evans function, also
provides additional spectral information. In particular, for each of the
families of detonation waves in our computational domain, we find a completely
unexpected kind of hysteresis in the limit of increasing activation energy;
that is, our calculations suggest that, whenever diffusive effects are present,
there is a return to stability as unstable eigenvalues return to the stable
complex half plane.


title:
Sharp uncertainty principles on Riemannian manifolds: the influence of
  curvature

abstract:
  We present a rigidity scenario for complete Riemannian manifolds supporting
the Heisenberg-Pauli-Weyl uncertainty principle with the sharp constant in
$\mathbb R^n$ (shortly, sharp HPW principle). Our results deeply depend on the
curvature of the Riemannian manifold which can be roughly formulated as
follows:
  (a) When $(M,g)$ has non-positive sectional curvature, the sharp HPW
principle holds on $(M,g)$. However, positive extremals exist in the sharp HPW
principle if and only if $(M,g)$ is isometric to $\mathbb R^n$, $n={\rm
dim}(M)$.
  (b) When $(M,g)$ has non-negative Ricci curvature, the sharp HPW principle
holds on $(M,g)$ if and only if $(M,g)$ is isometric to $\mathbb R^n$.
  Since the sharp HPW principle and the Hardy-Poincar\'e inequality are
endpoints of the Caffarelli-Kohn-Nirenberg interpolation inequality, we
establish further quantitative results for the latter inequalities in terms of
the curvature on Cartan-Hadamard manifolds.


title:
Dimension invariants for groups admitting a cocompact model for proper
  actions

abstract:
  Let $G$ be a group that admits a cocompact classifying space for proper
actions $X$. We derive a formula for the Bredon cohomological dimension for
proper actions of $G$ in terms of the relative cohomology with compact support
of certain pairs of subcomplexes of $X$. We use this formula to compute the
Bredon cohomological dimension for proper actions of fundamental groups of
non-positively curved simple complexes of finite groups. As an application we
show that if a virtually torsion-free group acts properly and chamber
transitively on a building, its virtual cohomological dimension coincides with
its Bredon cohomological dimension. This covers the case of Coxeter groups and
graph products of finite groups.


title: Matricial circular systems and random matrices

abstract:
  We introduce and study `matricial circular systems' of operators which play
the role of matricial counterparts of circular operators. They describe the
asymptotic joint *-distributions of blocks of independent block-identically
distributed Gaussian random matrices with respect to partial traces. Using
these operators, we introduce `circular free Meixner distributions' as the
non-Hermitian counterparts of free Meixner distributions and construct for them
a random matrix model. Our approach is based on the concept of matricial
freeness applied to operators on Hilbert spaces. It is closely related to
freeness with amalgamation over the algebra A of r x r diagonal matrices
applied to operators on Hilbert A-bimodules.


title: Synchronous Context-Free Grammars and Optimal Linear Parsing Strategies

abstract:
  Synchronous Context-Free Grammars (SCFGs), also known as syntax-directed
translation schemata, are unlike context-free grammars in that they do not have
a binary normal form. In general, parsing with SCFGs takes space and time
polynomial in the length of the input strings, but with the degree of the
polynomial depending on the permutations of the SCFG rules. We consider linear
parsing strategies, which add one nonterminal at a time. We show that for a
given input permutation, the problems of finding the linear parsing strategy
with the minimum space and time complexity are both NP-hard.


title: Non-Cancellation of Quantum Geometry Fluctuations

abstract:
  Quantum vacuum fluctuations tend to be strongly anti-correlated, which
reduces their observable effects. However, time dependence can upset the
cancellation of these anti-correlated fluctuations and greatly enhance their
effects. This form of non-cancellation is investigated for spacetime geometry
fluctuations driven by the vacuum stress tensor fluctuations of the
electromagnetic field. The time dependence can take the form of sinusoidal
conformal metric perturbations or of time variation of the gravitational
constant, both of which can arise from modifications of the gravitational
action. We examine two observable quantities, luminosity fluctuations and
redshift fluctuations, both of which can arise from stress tensor fluctuations.
We find that both quantities can grow with increasing distance between a source
and an observer. This secular growth raises the possibility of observing
spacetime geometry fluctuation effects at length scales far longer than the
Planck scale.


title: Rainbow Matchings and Hamilton Cycles in Random Graphs

abstract:
  Let $HP_{n,m,k}$ be drawn uniformly from all $k$-uniform, $k$-partite
hypergraphs where each part of the partition is a disjoint copy of $[n]$. We
let $HP^{(\k)}_{n,m,k}$ be an edge colored version, where we color each edge
randomly from one of $\k$ colors. We show that if $\k=n$ and $m=Kn\log n$ where
$K$ is sufficiently large then w.h.p. there is a rainbow colored perfect
matching. I.e. a perfect matching in which every edge has a different color. We
also show that if $n$ is even and $m=Kn\log n$ where $K$ is sufficiently large
then w.h.p. there is a rainbow colored Hamilton cycle in $G^{(n)}_{n,m}$. Here
$G^{(n)}_{n,m}$ denotes a random edge coloring of $G_{n,m}$ with $n$ colors.
When $n$ is odd, our proof requires $m=\om(n\log n)$ for there to be a rainbow
Hamilton cycle.


title:
Semistable Higgs bundles, periodic Higgs bundles and representations of
  algebraic fundamental groups

abstract:
  Let $k $ be the algebraic closure of a finite field of odd characteristic $p$
and $X$ a smooth projective scheme over the Witt ring $W(k)$ which is
geometrically connected in characteristic zero. We introduce the notion of
Higgs-de Rham flow and prove that the category of periodic Higgs-de Rham flows
over $X/W(k)$ is equivalent to the category of Fontaine modules, hence further
equivalent to the category of crystalline representations of the \'{e}tale
fundamental group $\pi_1(X_K)$ of the generic fiber of $X$, after
Fontaine-Laffaille and Faltings. Moreover, we prove that every semistable Higgs
bundle over the special fiber $X_k$ of $X$ of rank $\leq p$ initiates a
semistable Higgs-de Rham flow and thus those of rank $\leq p-1$ with trivial
Chern classes induce $k$-representations of $\pi_1(X_K)$. A fundamental
construction in this paper is the inverse Cartier transform over a truncated
Witt ring. In characteristic $p$, it was constructed by Ogus-Vologodsky in the
nonabelian Hodge theory in positive characteristic; in the affine local case,
our construction is related to the local Ogus-Vologodsky correspondence of
Shiho.


title: Robust Multimodal Graph Matching: Sparse Coding Meets Graph Matching

abstract:
  Graph matching is a challenging problem with very important applications in a
wide range of fields, from image and video analysis to biological and
biomedical problems. We propose a robust graph matching algorithm inspired in
sparsity-related techniques. We cast the problem, resembling group or
collaborative sparsity formulations, as a non-smooth convex optimization
problem that can be efficiently solved using augmented Lagrangian techniques.
The method can deal with weighted or unweighted graphs, as well as multimodal
data, where different graphs represent different types of data. The proposed
approach is also naturally integrated with collaborative graph inference
techniques, solving general network inference problems where the observed
variables, possibly coming from different modalities, are not in
correspondence. The algorithm is tested and compared with state-of-the-art
graph matching techniques in both synthetic and real graphs. We also present
results on multimodal graphs and applications to collaborative inference of
brain connectivity from alignment-free functional magnetic resonance imaging
(fMRI) data. The code is publicly available.


title: On the roots of $\sigma$-polynomials

abstract:
  Given a graph $G$ of order $n$, the $\sigma$-$polynomial$ of $G$ is the
generating function $\sigma(G,x) = \sum a_{i}x^{i}$ where $a_{i}$ is the number
of partitions of the vertex set of $G$ into $i$ nonempty independent sets. Such
polynomials arise in a natural way from chromatic polynomials. Brenti [1]
proved that $\sigma$-polynomials of graphs with chromatic number at least $n-2$
had all real roots, and conjectured the same held for chromatic number $n-3$.
We affirm this conjecture.


title:
Einstein@Home discovery of four young gamma-ray pulsars in Fermi LAT
  data

abstract:
  We report the discovery of four gamma-ray pulsars, detected in
computing-intensive blind searches of data from the Fermi Large Area Telescope
(LAT). The pulsars were found using a novel search approach, combining
volunteer distributed computing via Einstein@Home and methods originally
developed in gravitational-wave astronomy. The pulsars PSRs J0554+3107,
J1422-6138, J1522-5735, and J1932+1916 are young and energetic, with
characteristic ages between 35 and 56 kyr and spin-down powers in the range
$6\times10^{34}$ - $10^{36}$ erg s$^{-1}$. They are located in the Galactic
plane and have rotation rates of less than 10 Hz, among which the 2.1 Hz spin
frequency of PSR J0554+3107 is the slowest of any known gamma-ray pulsar. For
two of the new pulsars, we find supernova remnants coincident on the sky and
discuss the plausibility of such associations. Deep radio follow-up
observations found no pulsations, suggesting that all four pulsars are
radio-quiet as viewed from Earth. These discoveries, the first gamma-ray
pulsars found by volunteer computing, motivate continued blind pulsar searches
of the many other unidentified LAT gamma-ray sources.


title: Sudakov-type minoration for log-concave vectors

abstract:
  We formulate and discuss a conjecture concerning lower bounds for norms of
log-concave vectors, which generalizes the classical Sudakov minoration
principle for Gaussian vectors. We show that the conjecture holds for some
special classes of log-concave measures and some weaker forms of it are
satisfied in the general case. We also present some applications based on
chaining techniques.


title: Quasi-Hamiltonian reduction via classical Chern-Simons theory

abstract:
  This paper puts the theory of quasi-Hamiltonian reduction in the framework of
shifted symplectic structures developed by Pantev, To\"{e}n, Vaqui\'{e} and
Vezzosi. We compute the symplectic structures on mapping stacks and show how
the AKSZ topological field theory defined by Calaque allows one to neatly
package the constructions used in quasi-Hamiltonian reduction. Finally, we
explain how a prequantization of character stacks can be obtained purely
locally.


title:
Linear Transceiver design for Downlink Multiuser MIMO Systems:
  Downlink-Interference Duality Approach

abstract:
  This paper considers linear transceiver design for downlink multiuser
multiple-input multiple-output (MIMO) systems. We examine different transceiver
design problems. We focus on two groups of design problems. The first group is
the weighted sum mean-square-error (WSMSE) (i.e., symbol-wise or user-wise
WSMSE) minimization problems and the second group is the minimization of the
maximum weighted mean-squareerror (WMSE) (symbol-wise or user-wise WMSE)
problems. The problems are examined for the practically relevant scenario where
the power constraint is a combination of per base station (BS) antenna and per
symbol (user), and the noise vector of each mobile station is a zero-mean
circularly symmetric complex Gaussian random variable with arbitrary covariance
matrix. For each of these problems, we propose a novel downlink-interference
duality based iterative solution. Each of these problems is solved as follows.
First, we establish a new mean-square-error (MSE) downlink-interference
duality. Second, we formulate the power allocation part of the problem in the
downlink channel as a Geometric Program (GP). Third, using the duality result
and the solution of GP, we utilize alternating optimization technique to solve
the original downlink problem. For the first group of problems, we have
established symbol-wise and user-wise WSMSE downlink-interference duality.


title:
Deciphering the "chemical" nature of the exotic isotopes of Hydrogen by
  the MC-QTAIM analysis: The positively charged Muon and the Muonic Helium as
  new members of the Periodic Table

abstract:
  This report is a primarily survey on the chemical nature of some exotic
species containing the positively charged muon and the muonic Helium, i.e., the
negatively charged muon plus helium nucleus, as exotic isotopes of hydrogen,
using the newly developed multi-component quantum theory of atoms in molecules
(MC-QTAIM) analysis, employing ab initio non-Born-Oppenhiemer wavefunctions.
Accordingly, the "atoms in molecules" analysis performed on various asymmetric
exotic isotopomers of hydrogen molecule, recently detected experimentally
[Science 331, 448 (2011)], demonstrates that both the exotic isotopes are
capable of forming atoms in molecules and retaining the identity of hydrogen
atom. Various derived properties of atomic basins containing muonic helium cast
no doubt that apart from its short life time, it is a heavier isotope of
hydrogen while the properties of basins containing the positively charged muon
are more remote from those of the orthodox hydrogen basins, capable of
appreciable donation of electrons as well as large charge polarization;
however, with some tolerance, they may be categorized also as hydrogen basins
though with a smaller electronegativity. All in all, present study also clearly
demonstrates that the MC-QTAIM analysis is an efficient approach to decipher
the chemical nature of species containing exotic constituents, hard to be
elucidated by experimental and/or alternative theoretical schemes.


title:
Beyond the random phase approximation: Stimulated Brillouin backscatter
  for finite laser coherence times

abstract:
  We develop a statistical theory of stimulated Brillouin backscatter (BSBS) of
a spatially and temporally partially incoherent laser beam for laser fusion
relevant plasma. We find a new collective regime of BSBS (CBSBS) with intensity
threshold controlled by diffraction, an insensitive function of the laser
coherence time, $T_c$, once light travel time during $T_c$ exceeds a laser
speckle length. The BSBS spatial gain rate is approximately the sum of that due
to CBSBS, and a part which is independent of diffraction and varies linearly
with $T_c$. We find that the bandwidth of KrF-laser-based fusion systems would
be large enough to allow additional suppression of BSBS.


title:
Robust Sum MSE Optimization for Downlink Multiuser MIMO Systems with
  Arbitrary Power Constraint: Generalized Duality Approach

abstract:
  This paper considers linear minimum meansquare- error (MMSE) transceiver
design problems for downlink multiuser multiple-input multiple-output (MIMO)
systems where imperfect channel state information is available at the base
station (BS) and mobile stations (MSs). We examine robust sum mean-square-error
(MSE) minimization problems. The problems are examined for the generalized
scenario where the power constraint is per BS, per BS antenna, per user or per
symbol, and the noise vector of each MS is a zero-mean circularly symmetric
complex Gaussian random variable with arbitrary covariance matrix. For each of
these problems, we propose a novel duality based iterative solution. Each of
these problems is solved as follows. First, we establish a novel sum average
meansquare- error (AMSE) duality. Second, we formulate the power allocation
part of the problem in the downlink channel as a Geometric Program (GP). Third,
using the duality result and the solution of GP, we utilize alternating
optimization technique to solve the original downlink problem. To solve robust
sum MSE minimization constrained with per BS antenna and per BS power problems,
we have established novel downlink-uplink duality. On the other hand, to solve
robust sum MSE minimization constrained with per user and per symbol power
problems, we have established novel downlink-interference duality. For the
total BS power constrained robust sum MSE minimization problem, the current
duality is established by modifying the constraint function of the dual uplink
channel problem. And, for the robust sum MSE minimization with per BS antenna
and per user (symbol) power constraint problems, our duality are established by
formulating the noise covariance matrices of the uplink and interference
channels as fixed point functions, respectively.


title:
Down Converter Device Combining Rare-Earth Doped Thin Layer and Photonic
  Crystal for c-Si Based Solar Cell

abstract:
  The aim of the study is to develop ultra-compact structures enabling an
efficient conversion of single high energy photon (UV) to two lower energy
photons (IR). The proposed structure combines rare-earths doped thin layer
allowing the down-conversion process with a photonic crystal (PhC), in order to
control and enhance the down-conversion using optical resonances. On the top of
the rare-earths doped layer, a silicon nitride (SiN) 2D planar PhC is
synthesized. For that, SiN is first deposited by PECVD. After holographic
lithography and reactive ion etching, a periodic square lattice of holes is
generated on the SiN layer. The PhC topographical parameters as well as the
layers thickness are optimized using Finite-Difference-Time-Domain simulations.
The design and realization of such PhC-assisted down-converter structures is
presented. Optical simulations demonstrate that the PhC leads to the
establishment of resonant modes located in the underneath doped layer, allowing
a drastic enhancement of the absorption of the rare-earth ions without
disturbing the transmission in the visible and near-IR parts of the spectrum,
hence demonstrating the relevance of such an approach.


title:
Non parametric estimation of the diffusion coefficents of a diffusion
  with jumps

abstract:
  In this article, we consider a jump diffusion process (X_t), with drift
function b, diffusion coefficient sigma and jump coefficient xi^{2}. This
process is observed at discrete times t=0,Delta,...,nDelta. The sampling
interval Delta tends to 0 and nDelta tends to infinity. We assume that (X_t) is
ergodic, strictly stationary and exponentially beta-mixing. We use a penalized
least-square approach to compute adaptive estimators of the functions
sigma^2+xi^2 and sigma^2. We provide bounds for the risks of the two
estimators.


title:
Robust Transceiver Optimization for Downlink Coordinated Base Station
  Systems: Distributed Algorithm

abstract:
  This paper considers the joint transceiver design for downlink multiuser
multiple-input single-output (MISO) systems with coordinated base stations
(BSs) where imperfect channel state information (CSI) is available at the BSs
and mobile stations (MSs). By incorporating antenna correlation at the BSs and
taking channel estimation errors into account, we solve two robust design
problems: 1) minimizing the weighted sum of meansquare- error (MSE) with per BS
antenna power constraint, and 2) minimizing the total power of all BSs with per
user MSE target and per BS antenna power constraints. These problems are solved
as follows. First, for fixed receivers, we propose centralized and novel
computationally efficient distributed algorithms to jointly optimize the
precoders of all users. Our centralized algorithms employ the second-order-cone
programming (SOCP) approach, whereas, our novel distributed algorithms use the
Lagrangian dual decomposition, modified matrix fractional minimization and an
iterative method. Second, for fixed BS precoders, the receivers are updated by
the minimum mean-square-error (MMSE) criterion. These two steps are repeated
until convergence is achieved. In all of our simulation results, we have
observed that the proposed distributed algorithms achieve the same performance
as that of the centralized algorithms. Moreover, computer simulations verify
the robustness of the proposed robust designs compared to the non-robust/naive
designs.


title: Early Results from the Qweak Experiment

abstract:
  A subset of results from the recently completed Jefferson Lab Qweak
experiment are reported. This experiment, sensitive to physics beyond the
Standard Model, exploits the small parity-violating asymmetry in elastic ep
scattering to provide the first determination of the protons weak charge
Qweak(p). The experiment employed a 180 uA longitudinally polarized 1.16 GeV
electron beam on a 35 cm long liquid hydrogen target. Scattered electrons
corresponding to Q2 of 0.025 GeV2 were detected in eight Cerenkov detectors
arrayed symmetrically around the beam axis. The goals of the experiment were to
provide a measure of Qweak(p) to 4.2 percent (combined statistical and
systematic error), which implies a measure of sin2(thetaw) at the level of 0.3
percent, and to help constrain the vector weak quark charges C1u and C1d. The
experimental method is described, with particular focus on the challenges
associated with the worlds highest power LH2 target. The new constraints on C1u
and C1d provided by the subset of the experiments data analyzed to date will
also be shown, together with the extracted weak charge of the neutron.


title: Vlasov multi-dimensional model dispersion relation

abstract:
  A hybrid model of the Vlasov equation in multiple spatial dimension $D>1$ [H.
A. Rose and W. Daughton, Physics of Plasmas v. 18, 122109 (2011)], the Vlasov
multi dimensional model (VMD), consists of standard Vlasov dynamics along a
preferred direction, the $z$ direction, and $N$ flows. At each $z$ these flows
are in the plane perpendicular to the $z$ axis. They satisfy Eulerian-type
hydrodynamics with coupling by self-consistent electric and magnetic fields.
Every solution of the VMD is an exact solution of the original Vlasov equation.
We show convergence of the VMD Langmuir wave dispersion relation in thermal
plasma to that of Vlasov-Landau as $N$ increases. Rotational symmetry about the
$z$ axis in $3D$ of small perpendicular wavenumber Langmuir fluctuations is
demonstrated for $N\geq 6$, with flows arranged uniformly over the azimuthal
angle.


title: Robust Transceiver Optimization for Downlink Multiuser MIMO Systems

abstract:
  This paper addresses the joint transceiver design for downlink multiuser
multiple-input multiple-output (MIMO) systems, with imperfect channel state
information (CSI) at the base station (BS) and mobile stations (MSs). By
incorporating antenna correlation at both ends of the channel and taking
channel estimation errors into account, we solve two robust design problems:
minimization of the weighted sum mean-square-error (MSE) and minimization of
the maximum weighted MSE. These problems are solved as follows: first, we
establish three kinds of MSE uplink-downlink duality by transforming only the
power allocation matrices from uplink channel to downlink channel and vice
versa. Second, in the uplink channel, we formulate the power allocation part of
each problem ensuring global optimality. Finally, based on the solution of the
uplink power allocation and the MSE duality results, for each problem, we
propose an iterative algorithm that performs optimization alternatively between
the uplink and downlink channels. Computer simulations verify the robustness of
the proposed design compared to the non-robust/naive design.


title:
Weighted Sum Rate Optimization for Downlink Multiuser MIMO Systems with
  per Antenna Power Constraint: Downlink-Uplink Duality Approach

abstract:
  This paper considers weighted sum rate maximization constrained with a per
base station (BS) antenna power problem for multiuser multiple-input
multiple-output (MIMO) systems. For this problem, we propose new
downlink-uplink duality based solution. We solve the problem as follows. First,
by introducing additional optimization variables, we reformulate our problem
into an equivalent problem that incorporates a weighted sum mean-square-error
(MSE) term. Second, we establish novel weighted sum MSE duality. The duality is
established by modifying the input covariance matrix of the dual uplink
problem, and formulating the noise covariance matrix of the uplink channel as a
fixed point function. Third, we optimize the introduced variables and powers in
the downlink channel by a Geometric Program (GP) method. Fourth, using the
duality result and the solution of GP, we apply alternating optimization
technique to solve the original downlink problem. In our simulation results, we
have observed that the proposed duality based solution utilizes less power than
that of existing algorithms.


title:
Modeling the Time-varying Subjective Quality of HTTP Video Streams with
  Rate Adaptations

abstract:
  Newly developed HTTP-based video streaming technologies enable flexible
rate-adaptation under varying channel conditions. Accurately predicting the
users' Quality of Experience (QoE) for rate-adaptive HTTP video streams is thus
critical to achieve efficiency. An important aspect of understanding and
modeling QoE is predicting the up-to-the-moment subjective quality of a video
as it is played, which is difficult due to hysteresis effects and
nonlinearities in human behavioral responses. This paper presents a
Hammerstein-Wiener model for predicting the time-varying subjective quality
(TVSQ) of rate-adaptive videos. To collect data for model parameterization and
validation, a database of longer-duration videos with time-varying distortions
was built and the TVSQs of the videos were measured in a large-scale subjective
study. The proposed method is able to reliably predict the TVSQ of rate
adaptive videos. Since the Hammerstein-Wiener model has a very simple
structure, the proposed method is suitable for on-line TVSQ prediction in HTTP
based streaming.


title: Strong stationary times for one-dimensional diffusions

abstract:
  A necessary and sufficient condition is obtained for the existence of strong
stationary times for ergodic one-dimensional diffusions, whatever the initial
distribution. The strong stationary times are constructed through intertwinings
with dual processes, in the Diaconis-Fill sense, taking values in the set of
segments of the extended line $\mathbb{R}\sqcup\{-\infty,+\infty\}$. They can
be seen as natural $h$-transforms of the extensions to the diffusion framework
of the evolving sets of Morris-Peres. Starting from a singleton set, the dual
process begins by evolving into true segments in the same way a Bessel process
of dimension 3 escapes from 0. The strong stationary time corresponds to the
first time the full segment $[-\infty,+\infty]$ is reached. The benchmark
Ornstein-Uhlenbeck process cannot be treated in this way, it will nevertheless
be seen how to use other strong times to recover its optimal exponential rate
of convergence in the total variation sense.


title:
Probabilistic generation of random networks taking into account
  information on motifs occurrence

abstract:
  Because of the huge number of graphs possible even with a small number of
nodes, inference on network structure is known to be a challenging problem.
Generating large random directed graphs with prescribed probabilities of
occurrences of some meaningful patterns (motifs) is also difficult. We show how
to generate such random graphs according to a formal probabilistic
representation, using fast Markov chain Monte Carlo methods to sample them. As
an illustration, we generate realistic graphs with several hundred nodes
mimicking a gene transcription interaction network in Escherichia coli.


title: Cosmic Emulation: Fast Predictions for the Galaxy Power Spectrum

abstract:
  The halo occupation distribution (HOD) approach has proven to be an effective
method for modeling galaxy clustering and bias. In this approach, galaxies of a
given type are probabilistically assigned to individual halos in N-body
simulations. In this paper, we present a fast emulator for predicting the fully
nonlinear galaxy power spectrum over a range of freely specifiable HOD modeling
parameters. The emulator is constructed using results from 100 HOD models run
on a large LCDM N-body simulation, with Gaussian Process interpolation applied
to a PCA-based representation of the galaxy power spectrum. The total error is
currently ~3% (~2% in the simulation and ~1% in the emulation process) from z=1
to z=0, over the considered parameter range. We use the emulator to investigate
parametric dependencies in the HOD model, as well as the behavior of galaxy
bias as a function of HOD parameters. The emulator is publicly available at
http://www.hep.anl.gov/cosmology/CosmicEmu/emu.html.


title:
Preparation of a clay based superabsorbent polymer composite of
  copolymer poly(acrylate-co-acrylamide) with bentonite via microwave radiation

abstract:
  In this paper we present a fast, new and easy method for the preparation of
bentonite-g-poly(acrylate-co-acrylamide) composite material using microwave
radiation. The composite has water absorptivity of 1002 g/g while the
corresponding copolymer is tacky and has poor gel texture. The relative thermal
stability of the composite in comparison with the copolymer was proved via
thermogravimetric analysis These results indicate the synergistic effect of the
bentonite with the copolymer by increasing water absorptivity and enhancing
thermal and mechanical properties of the final gel. The composite was
characterized by X-ray and FTIR. The influence of the environmental parameters
on water absorptivity such as the pH and the ionic force was investigated


title: Sum Rate Optimization for Coordinated Multi-Antenna Base Station Systems

abstract:
  This paper considers the joint precoder design problem for multiple-input
single-output (MISO) systems with coordinated base stations (BSs). We consider
maximization of the total sum rate with per BS antenna power constraint
problem. For this problem, we propose a novel linear iterative algorithm. The
problem is solved as follows. First, by introducing additional optimization
variables and applying matrix fractional minimization, we reformulate the
original problem as a new problem. Second, for the given precoder vectors of
all users, we optimize the introduced variables of the latter problem using
Geometric Programming (GP) method. Third, keeping the introduced variables
constant, the precoder vectors of all users are optimized by using phase
rotation technique. The second and third steps are repeated until convergence.
We have shown that the proposed algorithm is guaranteed to converge. Moreover,
for the total sum power constraint case, simulation results show that the
proposed iterative algorithm achieves almost the same average performance as
that of the algorithm which utilizes mean-square-error (MSE) uplink-downlink
duality approach. We also show that our iterative algorithm can be used to
solve sum rate maximization and weighted sum MSE minimization problems for an
arbitrary power constraint.


title: What did we learn in theory from the $\Delta A_{CP}$-saga?

abstract:
  The measurement of CP violation in the charm sector triggered a lot of
theoretical activities and re-considerations. Nevertheless currently neither
theory nor experiment have reached definite conclusions about the origin of a
large CP violating effect in hadronic $D$ decays. We review briefly (part of)
the current theory literature and present as the most important outcome of the
many investigations initial steps in a long journey to understand the standard
model contribution to hadronic $D$ meson decays from first principles as well
as various control channels, that can be studied by experiment.


title: Nonequilibrium and irreversibility

abstract:
  The booklet contain an overview on selected recent developments in
nonequilibrium statistical mechanics and chaos theory: SRB distributions,
chaotic hypothesis, fluctuation theorem, proposals for tests and applications
to granular materials, fluidodynamics, irreversibility of quasi static
processes. In appendices examples of the kind of technical work necessary for
actual construction of nonequilibrium stationary states.

categories: cond-mat.stat-mech math-ph math.MP nlin.CD


title:
Multi-cycle Cyclostationary based Spectrum Sensing Algorithm for OFDM
  Signals with Noise Uncertainty in Cognitive Radio Networks

abstract:
  This paper proposes a simple multi-cycle cyclostationary based signal
detection (spectrum sensing) algorithm for Orthogonal Frequency Division
Multiplexed (OFDM) signals in cognitive radio networks. We assume that the
noise samples are independent and identically distributed (i.i.d) random
variables all with unknown (imperfect) variance. Our detection algorithm employ
the following three steps. First, we formulate the test statistics as a ratio
of two quadratic cyclic autocorrelation functions. Second, we derive a closed
form expression for the false alarm probability. Third, we evaluate the
detection probability of our algorithm for a given false alarm probability. The
theoretical probability of false alarm expression matches with that of the
simulation result. Moreover, we have observed that the proposed multi-cycle
algorithm exhibits significantly superior probability of detection compared to
the existing low complexity cyclostationary based and the well known energy
detection algorithms.


title:
Representation and regularity for the Dirichlet problem for real and
  complex degenerate Hessian equations

abstract:
  We consider the Dirichlet problem for positively homogeneous, degenerate
elliptic, concave (or convex) Hessian equations. Under natural and necessary
conditions on the geometry of the domain, with the $C^{1,1}$ boundary data, we
establish the interior $C^{1,1}$-regularity of the unique (admissible)
solution, which is optimal even if the boundary data is smooth. Both real and
complex cases are studied by the unified (Bellman equation) approach.