title: Charged current quasi elastic scattering of muon neutrino with nuclei

abstract:
  We present a study on the charge current quasi elastic scattering of
$\nu_\mu$ from nucleon and nuclei which gives a charged muon in the final
state. To describe nuclei, the Fermi Gas model has been used with proposed
Pauli suppression factor. The diffuseness parameter of the Fermi distribution
has been obtained using experimental data. We also investigate different
parametrizations for electric and magnetic Sach's form factors of nucleons.
Calculations have been made for CCQES total and differential cross sections for
the cases of $\nu_{\mu}-N$, $\nu_{\mu}-^{12}C$ and $\nu_{\mu}-^{56}Fe$
scatterings and are compared with the data for different values of the axial
mass. The present model gives excellent description of measured differential
cross section for all the systems.


title:
The open XXX spin chain in the SoV framework: scalar product of separate
  states

abstract:
  We consider the XXX open spin-1/2 chain with the most general non-diagonal
boundary terms, that we solve by means of the quantum separation of variables
(SoV) approach. We compute the scalar products of separate states, a class of
states which notably contains all the eigenstates of the model. As usual for
models solved by SoV, these scalar products can be expressed as some
determinants with a non-trivial dependance in terms of the inhomogeneity
parameters that have to be introduced for the method to be applicable. We show
that these determinants can be transformed into alternative ones in which the
homogeneous limit can easily be taken. These new representations can be
considered as generalizations of the well-known determinant representation for
the scalar products of the Bethe states of the periodic chain. In the
particular case where a constraint is applied on the boundary parameters, such
that the transfer matrix spectrum and eigenstates can be characterized in terms
of polynomial solutions of a usual T-Q equation, the scalar product that we
compute here corresponds to the scalar product between two off-shell Bethe-type
states. If in addition one of the states is an eigenstate, the determinant
representation can be simplified, hence leading in this boundary case to direct
analogues of algebraic Bethe ansatz determinant representations of the scalar
products for the periodic chain.

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


title: On the Hamiltonian formalism of the tetrad-gravity

abstract:
  We present a detailed analysis of the Hamiltonian constraints of the
d-dimensional tetrad-connection gravity where the non-dynamical part of the
spatial connection is fixed to zero by an adequate guage transformation. This
new action depending on the co-tetrad and the dynamical part of the spatial
connection leads to Lorentz, scalar and vectorial first-class polynomial
constraints obeying a closed algebra in terms of Poisson brackets. This algebra
closes on the structure constants instead of structure functions resulting from
the Hamiltonian formalisms based on the A.D.M. decomposition. The same algebra
of the reduced first-class constraints defined on the reduced phase-space,
where the second-class constraints are solved, is obtained in terms of Dirac
brackets. These first-class constraintslead to the same physical degrees of
freedom of the general relativity. PACS numbers: 04.20.Cv, 04.20.Fy, 11.10.Ef,
11.30.Cp


title: Scattering of low lying states in the black hole atmosphere

abstract:
  We investigate finite $\alpha '$ effects in string theory on a black hole
background. By explicitly computing tree level scattering amplitudes, we
confirm a duality between seemingly different states recently conjectured by
Giveon, Itzhaki, and Kutasov in [arXiv:1603.05822]. We verify that the relevant
3-point functions factorize in such a way that the duality between oscillator
and winding states becomes manifest. This leads to determine the precise
normalization of the dual vertex operators, and confirms at the level of the
interacting theory the identification of states suggested by the analysis of
the spectrum. This result implies a duality between two seemingly distinct
mechanisms driving the violation of the string winding number in the black hole
atmosphere.


title:
Extended Majorana zero modes in a topological superconducting-normal
  T-junction

abstract:
  We investigate the sub gap properties of a three terminal Josephson
T-junction composed of topologically superconducting wires connected by a
normal metal region. This system naturally hosts zero energy Andreev bound
states which are of self-conjugate Majorana nature and we show that they are,
in contrast to ordinary Majorana zero modes, spatially extended in the normal
metal region. If the T-junction respects time-reversal symmetry, we show that a
zero mode is distributed only in two out of three arms in the junction and
tuning the superconducting phases allows for transfer of the mode between the
junction arms. We further provide tunneling conductance calculations showing
that these features can be detected in experiments. Our findings suggest an
experimental platform for studying the nature of spatially extended Majorana
zero modes.


title:
Primary Channel Gain Estimation for Spectrum Sharing in Cognitive Radio
  Networks

abstract:
  In cognitive radio networks, the channel gain between primary transceivers,
namely, primary channel gain, is crucial for a cognitive transmitter (CT) to
control the transmit power and achieve spectrum sharing. Conventionally, the
primary channel gain is estimated in the primary system and thus unavailable at
the CT. To deal with this issue, two estimators are proposed by enabling the CT
to sense primary signals. In particular, by adopting the maximum likelihood
(ML) criterion to analyze the received primary signals, a ML estimator is first
developed. After demonstrating the high computational complexity of the ML
estimator, a median based (MB) estimator with proved low complexity is then
proposed. Furthermore, the estimation accuracy of the MB estimation is
theoretically characterized. By comparing the ML estimator and the MB estimator
from the aspects of the computational complexity as well as the estimation
accuracy, both advantages and disadvantages of two estimators are revealed.
Numerical results show that the estimation errors of the ML estimator and the
MB estimator can be as small as $0.6$ dB and $0.7$ dB, respectively.


title:
Notes on the Vollhardt "invariant" and phase transition in the helical
  itinerant magnet MnSi

abstract:
  In this paper we argue that rounded "hills" or "valleys" demonstrated by the
heat capacity, thermal expansion coefficient, and elastic module are
indications of a smeared second order phase transition, which is flattened and
spread out by the application of a magnetic field. As a result, some of the
curves which display a temperature dependence of the corresponding quantities
cross almost at a single point. Thus, the Vollhardt crossing point should not
be identified with any specific energy scale. The smeared phase transition in
MnSi preceding the helical first order transition most probably corresponds to
the planar ferromagnetic ordering, with a small or negligible correlation
between planes. At lower temperatures, the system of ferromagnetic planes
becomes correlated, acquiring a helical twist.


title: Near Counterexamples to Weil's Converse Theorem

abstract:
  We show that in Weil's converse theorem the functional equations of
multiplicative twists for at least the first $\sqrt{\frac{p-24}{3}}$ moduli are
needed in order to prove the modularity for $\Gamma_0(p)$.


title:
Self-consistent spin-wave analysis of the 1/3 magnetization plateau in
  the kagome antiferromagnet

abstract:
  We propose a modified spin-wave theory to study the 1/3 magnetization plateau
of the antiferromagnetic Heisenberg model on the kagome lattice. By the
self-consistent inclusion of quantum corrections, the 1/3 plateau is stabilized
over a broad range of magnetic fields for all spin quantum numbers, S. The
values of the critical magnetic fields and the widths of the magnetization
plateaus are fully consistent with recent numerical results from exact
diagonalization and infinite projected entangled paired states.


title: Using emulation to validate applications on opportunistic networks

abstract:
  The increasing trend on wireless-connected devices makes opportunistic
networking a promising alternative to existing infrastructure-based networks.
However, on these networks there is neither guarantee about the availability of
the connections nor on the topology of the network. The development of
opportunistic applications, i.e., applications running over opportunistic
networks, is still in early stages. This is due to lack of tools to support the
process in such uncertain conditions. Indeed, many tools have been introduced
to study and characterize opportunistic networks, but none of them is focused
on helping developers to conceive opportunistic applications. In this paper, we
argue that the gap between opportunistic applications development and network
characterization can be filled with network emulation. First, this position
paper points out important challenges about the development of opportunistic
applications. Then, in order to cope with these challenges, it details a set of
requirements that an emulator should meet to allow the testing of such
applications.


title:
Think Eternally: Improved Algorithms for the Temp Secretary Problem and
  Extensions

abstract:
  The \emph{Temp Secretary Problem} was recently introduced by Fiat et al. It
is a generalization of the Secretary Problem, in which commitments are
temporary for a fixed duration. We present a simple online algorithm with
improved performance guarantees for cases already considered by Fiat et al.\
and give competitive ratios for new generalizations of the problem. In the
classical setting, where candidates have identical contract durations $\gamma
\ll 1$ and we are allowed to hire up to $B$ candidates simultaneously, our
algorithm is $(\frac{1}{2} - O(\sqrt{\gamma}))$-competitive. For large $B$, the
bound improves to $1 - O\left(\frac{1}{\sqrt{B}}\right) - O(\sqrt{\gamma})$.
  Furthermore we generalize the problem from cardinality constraints towards
general packing constraints. We achieve a competitive ratio of $1 -
O\left(\sqrt{\frac{(1+\log d + \log B)}{B}}\right) -O(\sqrt{\gamma})$, where
$d$ is the sparsity of the constraint matrix and $B$ is generalized to the
capacity ratio of linear constraints. Additionally we extend the problem
towards arbitrary hiring durations.
  Our algorithmic approach is a relaxation that aggregates all temporal
constraints into a non-temporal constraint. Then we apply a linear scaling
algorithm that, on every arrival, computes a tentative solution on the input
that is known up to this point. This tentative solution uses the non-temporal,
relaxed constraints scaled down linearly by the amount of time that has already
passed.


title:
Coupled-Channel Effects for the Bottomonium with Realistic Wave
  Functions

abstract:
  With Gaussian expansion method (GEM), realistic wave functions are used to
calculate coupled-channel effects for the bottomonium under the framework of
${}^3P_0$ model. The simplicity and accuracy of GEM are explained. We calculate
the mass shifts, probabilities of the $B$ meson continuum, $S-D$ mixing angles,
strong and dielectric decay widths. Our calculation shows that both $S-D$
mixing and the $B$ meson continuum can contribute to the suppression of the
vector meson's dielectric decay width. We suggest more precise measurements on
the radiative decays of $\Upsilon(10580)$ and $\Upsilon(11020)$ to distinguish
these two effects. The above quantities are also calculated with simple
harmonic oscillator (SHO) wave function approximation for comparison. The
deviation between GEM and SHO indicates that it is essential to treat the wave
functions accurately for near threshold states.


title:
Peculiar double-periodic pulsation in RR Lyrae stars of the OGLE
  collection. I. Long-period stars with dominant radial fundamental mode

abstract:
  We present the discovery of a new, peculiar form of double-periodic pulsation
in RR Lyrae stars. In four, long-period ($P>0.6$ d) stars observed by the
Optical Gravitational Lensing Experiment, and classified as fundamental mode
pulsators (RRab), we detect additional, low-amplitude variability, with period
shorter than fundamental mode period. The period ratios fall in a range similar
to double-mode fundamental and first overtone RR Lyrae stars (RRd), with the
exception of one star, in which the period ratio is significantly lower and
nearly exactly equals 0.7. Although period ratios are fairly different for the
four stars, the light curve shapes corresponding to the dominant, fundamental
mode are very similar. The peak-to-peak amplitudes and amplitude ratios
(Fourier parameters $R_{21}$ and $R_{31}$) are among the highest observed in
RRab stars of similar period, while Fourier phases ($\varphi_{21}$ and
$\varphi_{31}$) are among the lowest observed in RRab stars.
  If the additional variability is interpreted as due to radial first overtone,
then, the four stars are the most extreme RRd variables of the longest
pulsation periods known. Indeed, the observed period ratios can be well
modelled with high metallicity pulsation models. However, at such long
pulsation periods, first overtone is typically damped.
  Five other candidates, with weak signature of additional variability, sharing
the same characteristics, were also detected and are briefly discussed.


title:
Partitions of the set of nonnegative integers with the same
  representation functions

abstract:
  For a set of nonnegative integers $S$ let $R_{S}(n)$ denote the number of
unordered representations of the integer $n$ as the sum of two different terms
from $S$. In this paper we focus on partitions of the natural numbers into two
sets affording identical representation functions. We solve a recent problem of
Lev and Chen.


title: Semidefinite bounds for mixed binary/ternary codes

abstract:
  For nonnegative integers $n_2, n_3$ and $d$, let $N(n_2,n_3,d)$ denote the
maximum cardinality of a code of length $n_2+n_3$, with $n_2$ binary
coordinates and $n_3$ ternary coordinates (in this order) and with minimum
distance at least $d$. For a nonnegative integer $k$, let $\mathcal{C}_k$
denote the collection of codes of cardinality at most $k$. For $D \in
\mathcal{C}_k$, define $S(D) := \{C \in \mathcal{C}_k \mid D \subseteq C, |D|
+2|C\setminus D| \leq k\}$. Then $N(n_2,n_3,d)$ is upper bounded by the maximum
value of $\sum_{v \in [2]^{n_2}[3]^{n_3}}x(\{v\})$, where $x$ is a function
$\mathcal{C}_k \rightarrow \mathbb{R}$ such that $x(\emptyset) = 1$ and $x(C) =
0$ if $C$ has minimum distance less than $d$, and such that the $S(D)\times
S(D)$ matrix $(x(C\cup C'))_{C,C' \in S(D)}$ is positive semidefinite for each
$D \in \mathcal{C}_k$. By exploiting symmetry, the semidefinite programming
problem for the case $k=3$ is reduced using representation theory. It yields
$135$ new upper bounds that are provided in tables


title: Garbled Quantum Computation

abstract:
  The universal blind quantum computation protocol (UBQC) (Broadbent,
Fitzsimons, Kashefi 2009) enables an almost classical client to delegate a
quantum computation to an untrusted quantum server (in form of a garbled
quantum computation) while the security for the client is unconditional. In
this contribution we explore the possibility of extending the verifiable UBQC
(Fitzsimons, Kashefi 2012), to achieve further functionalities as was done for
classical garbled computation. First, exploring the asymmetric nature of UBQC
(client preparing only single qubits, while the server runs the entire quantum
computation), we present a "Yao" type protocol for secure two party quantum
computation. Similar to the classical setting (Yao 1986) our quantum Yao
protocol is secure against a specious (quantum honest-but-curious) garbler, but
in our case, against a (fully) malicious evaluator. Unlike the protocol in
(Dupuis, Nielsen, Salvail 2010), we do not require any online-quantum
communication between the garbler and the evaluator and thus no extra
cryptographic primitive. This feature will allow us to construct a simple
universal one-time compiler for any quantum computation using one-time memory,
in a similar way with the classical work of (Goldwasser, Kalai, Rothblum 2008)
while more efficiently than the previous work of (Broadbent, Gutoski, Stebila
2013).


title:
Pattern formation for a volume-filling chemotaxis model with logistic
  growth

abstract:
  This paper is devoted to investigate the pattern formation of a
volume-filling chemotaxis model with logistic cell growth. We first apply the
local stability analysis to establish sufficient conditions of destabilization
for uniform steady-state solution. Then, weakly nonlinear analysis with
multi-scales is used to deal with the emerging process of patterns near the
bifurcation point. For the single unstable mode case, we derive the
Stuart-Landau equations describing the evolution of the amplitude, and thus the
asymptotic expressions of patterns are obtained in both supercritical case and
subcritical case. While for the case of multiple unstable modes, we also derive
coupled amplitude equations to study the competitive behavior between two
unstable modes through the phase plane analysis. In particular, we find that
the initial data play a dominant role in the competition. All the theoretical
and numerical results are in excellently qualitative agreement and better
quantitative agreement than that in [1]. Moreover, in the subcritical case, we
confirm the existence of stationary patterns with larger amplitudes when the
bifurcation parameter is less than the first bifurcation point, which gives an
positive answer to the open problem proposed in [2].


title: Breaking of the site-bond percolation universality in networks

abstract:
  The stochastic addition of either vertices or connections in a network leads
to the observation of the percolation transition, a structural change with the
appearance of a connected component encompassing a finite fraction of the
system. Percolation has always been regarded as a substrate-dependent but
model-independent process, in the sense that the critical exponents of the
transition are determined by the geometry of the system, but they are identical
for the bond and site percolation models. Here, we report a violation of such
assumption. We provide analytical and numerical evidence of a difference in the
values of the critical exponents between the bond and site percolation models
in networks with null percolation thresholds, such as scale-free graphs with
diverging second moment of the degree distribution. We discuss possible
implications of our results in real networks, and provide additional insights
on the anomalous nature of the percolation transition with null threshold.


title:
Estimation for stochastic damping Hamiltonian systems under partial
  observation. III. Diffusion term

abstract:
  This paper is the third part of our study started with Cattiaux, Le\'{o}n and
Prieur [Stochastic Process. Appl. 124 (2014) 1236-1260; ALEA Lat. Am. J.
Probab. Math. Stat. 11 (2014) 359-384]. For some ergodic Hamiltonian systems,
we obtained a central limit theorem for a nonparametric estimator of the
invariant density [Stochastic Process. Appl. 124 (2014) 1236-1260] and of the
drift term [ALEA Lat. Am. J. Probab. Math. Stat. 11 (2014) 359-384], under
partial observation (only the positions are observed). Here, we obtain
similarly a central limit theorem for a nonparametric estimator of the
diffusion term.


title: On the abelian complexity of the Rudin-Shapiro sequence

abstract:
  In this paper, we study the abelian complexity of the Rudin-Shapiro sequence
and a related sequence. We show that these two sequences share the same
complexity function $\rho(n)$ which satisfies certain recurrence relations. As
a consequence, the abelian complexity function is $2$-regular. Further, we
prove that the box dimension of the graph of the asymptotic function
$\lambda(x)$ is $3/2$ where
$\lambda(x)=\lim_{k\to\infty}\rho(4^{k}x)/\sqrt{4^{k}x}$ and
$\rho(x)=\rho(\lfloor x\rfloor)$ for any $x> 0$.


title: Electro-hydrodynamic synchronization of piezoelectric flags

abstract:
  Hydrodynamic coupling of flexible flags in axial flows may profoundly
influence their flapping dynamics, in particular driving their synchronization.
This work investigates the effect of such coupling on the harvesting efficiency
of coupled piezoelectric flags, that convert their periodic deformation into an
electrical current. Considering two flags connected to a single output circuit,
we investigate using numerical simulations the relative importance of
hydrodynamic coupling to electrodynamic coupling of the flags through the
output circuit due to the inverse piezoelectric effect. It is shown that
electrodynamic coupling is dominant beyond a critical distance, and induces a
synchronization of the flags' motion resulting in enhanced energy harvesting
performance. We further show that this electrodynamic coupling can be
strengthened using resonant harvesting circuits.


title:
High Resolution Optical Spectroscopy and Magnetic Properties of Yb3+ in
  Y2SiO5

abstract:
  Rare earth doped crystals are promising systems for quantum information
processing. In particular paramagnetic rare earths could be used to build
coherent interfaces with optical and microwave photons. In addition, isotopes
with non zero nuclear spins could provide long lived states for quantum state
storage and processing. Yb3+ is particularly interesting in this respect since
it is the only paramagnetic rare earth with a spin 1/2 isotope, which
corresponds to the simplest possible level structure. In this paper, we report
on the optical and magnetic properties of Yb3+ in the two sites of Y2SiO5, a
commonly used crystal for quantum applications. We measured optical
inhomogeneous linewidths, peak absorption coefficients, oscillator strengths,
excited state lifetimes and fuorescence branching ratios. The Zeeman tensors
were also determined in the ground and excited states, as well as the ground
state hyperfine tensor for the 171Yb3+ (I = 1=2) isotope. These results suggest
that Yb3+:Y2SiO5 is a promising material for applications like solid state
optical and microwave quantum memories.


title: Reflexive measurements, self-inspection and self-representation

abstract:
  There exist limits of self-inspection due to self-referential paradoxes,
incompleteness and fixed point theorems. As quantum mechanics dictates the
exchange of discrete quanta, measurements and self-inspection of quantized
systems are fundamentally limited.


title: On bases of some simple modules of symmetric groups and Hecke algebras

abstract:
  We consider simple modules for a Hecke algebra with a parameter of quantum
characteristic $e$. Equivalently, we consider simple modules $D^{\lambda}$,
labelled by $e$-restricted partitions $\lambda$ of $n$, for a cyclotomic KLR
algebra $R_n^{\Lambda_0}$ over a field of characteristic $p\ge 0$, with mild
restrictions on $p$. If all parts of $\lambda$ are at most $2$, we identify a
set $\mathsf{DStd}_{e,p}(\lambda)$ of standard $\lambda$-tableaux, which is
defined combinatorially and naturally labels a basis of $D^{\lambda}$. In
particular, we prove that the $q$-character of $D^{\lambda}$ can be described
in terms of $\mathsf{DStd}_{e,p}(\lambda)$. We show that a certain natural
approach to constructing a basis of an arbitrary $D^{\lambda}$ does not work in
general, giving a counterexample to a conjecture of Mathas.


title: Minimum Rectilinear Polygons for Given Angle Sequences

abstract:
  A rectilinear polygon is a polygon whose edges are axis-aligned. Walking
counterclockwise on the boundary of such a polygon yields a sequence of left
turns and right turns. The number of left turns always equals the number of
right turns plus 4. It is known that any such sequence can be realized by a
rectilinear polygon. In this paper, we consider the problem of finding
realizations that minimize the perimeter or the area of the polygon or the area
of the bounding box of the polygon. We show that all three problems are NP-hard
in general. This answers an open question of Patrignani [CGTA 2001], who showed
that it is NP-hard to minimize the area of the bounding box of an orthogonal
drawing of a given planar graph. We also show that realizing polylines with
minimum bounding box area is NP-hard. Then we consider the special cases of
$x$-monotone and $xy$-monotone rectilinear polygons. For these, we can optimize
the three objectives efficiently.


title:
Disordered double Weyl node: Comparison of transport and
  density-of-states calculations

abstract:
  Double Weyl nodes are topologically protected band crossing points which
carry chiral charge $\pm2$. They are stabilized by $C_{4}$ point group symmetry
and are predicted to occur in $\mathrm{SrSi_{2}}$ or $\mathrm{HgCr_{2}Se_{4}}$.
We study their stability and physical properties in the presence of a disorder
potential. We investigate the density of states and the quantum transport
properties at the nodal point. We find that, in contrast to their counterparts
with unit chiral charge, double Weyl nodes are unstable to any finite amount of
disorder and give rise to a diffusive phase, in agreement with predictions of
Goswami and Nevidomskyy [Phys. Rev. B 92, 214504 (2015)] and Bera, Sau, and Roy
[Phys. Rev. B 93, 201302(R) (2016)]. However, for finite system sizes a
crossover between pseudodiffusive and diffusive quantum transport can be
observed.


title: Quasisymmetric (k,l)-hook Schur functions

abstract:
  We introduce a quasisymmetric generalization of Berele and Regev's hook Schur
functions and prove that these new quasisymmetric hook Schur functions
decompose the hook Schur functions in a natural way. We examine the
combinatorics of the quasisymmetric hook Schur functions, providing a
relationship to Gessel's fundamental quasisymmetric functions and an analogue
of the Robinson-Schensted-Knuth algorithm. We also prove that the
multiplication of quasisymmetric hook Schur functions with hook Schur functions
behaves the same as the multiplication of quasisymmetric Schur functions with
Schur functions.


title: Isospin violating decays of positive parity $B_s$ mesons in HM$\chi$PT

abstract:
  Recent lattice QCD results suggest that the masses of the first two positive
parity $B_s$ mesons lie below the BK threshold, similar to the case of
$D^*_{s0}(2317)^+$ and $D_{s1}(2460)^+$ mesons. The mass spectrum of $B_s$
mesons seems to follow pattern of $D_s$ mass spectrum. As in the case of
charmed mesons, the structure of positive parity $B_s$ mesons is very
intriguing. To shed more light on this issue, we investigate strong isospin
violating decays $B_s(0^+) \to B_s^0 \pi^0$, $B_s(1^+) \to B_s^{*0} \pi^0$ and
$B_s(1^+) \to B_s^0 \pi \pi$ within heavy meson chiral perturbation theory. The
two body decay amplitude arises at the tree level and we show that the loop
corrections give significant contributions. On the other hand, in the case of
three body decay $B_s(1^+) \to B_s^0 \pi \pi$ amplitude occurs only at the loop
level. We find that the decay widths for these decays are: $\Gamma (B_s(1^+)
\to B_s^0 \pi \pi)\sim 10^{-3}\,$keV and $\Gamma (B_s(0^+) \to B_s^0 \pi^0)
\leq 55\,$keV, $\Gamma (B_s(1^+) \to B_s^{*0} \pi^0) \leq 50\,$keV. More
precise knowledge of the coupling constant describing the interaction of
positive and negative parity heavy mesons with light pseudoscalar mesons would
help to increase accuracy of our calculation.


title:
Thermodynamic stability of mixed Pb:Sn methyl-ammonium halide
  perovskites

abstract:
  Using density functional theory, we investigate systematically mixed
MA(Pb:Sn)X3 perovskites, where MA is CH3NH3+, and X is Cl, Br, or I. Ab initio
calculations of the orthorhombic, tetragonal, and cubic perovskite phases show
that the substitution of lead by tin has a much weaker influence on both
structure and cohesive energies than the substitution of the halogen. The
thermodynamic stability of the MA(Pb:Sn)X3 mixtures at finite, non-zero
temperatures is studied within the Regular Solution Model. We predict that it
will be possible to create MA(Pb:Sn)I3 mixtures at any temperature. Our results
imply that mixing is unlikely for the low-temperature phase of bromide and
chloride compounds, where instead local clusters are more likely to form. We
further predict that in the high-temperature cubic phase, Pb and Sn compounds
will mix for both MA(Pb:Sn)Br3 and MA(Pb:Sn)Cl3 due to the entropy contribution
to the Helmholtz free energy.


title:
The microlensing rate and distribution of free-floating planets towards
  the Galactic bulge

abstract:
  Ground-based optical microlensing surveys have provided tantalising, if
inconclusive, evidence for a significant population of free-floating planets
(FFPs). Both ground and space-based facilities are being used and developed
which will be able to probe the distrubution of FFPs with much better
sensitivity. It is vital also to develop a high-precision microlensing
simulation framework to evaluate the completeness of such surveys. We present
the first signal-to-noise limited calculations of the FFP microlensing rate
using the Besancon Galactic model. The microlensing distribution towards the
Galactic centre is simulated for wide-area ground-based optical surveys such as
OGLE or MOA, a wide-area ground-based near-IR survey, and a targeted
space-based near-IR survey which could be undertaken with Euclid or WFIRST. We
present a calculation framework for the computation of the optical and
near-infrared microlensing rate and optical depth for simulated stellar
catalogues which are signal-to-noise limited, and take account of extinction,
unresolved stellar background light and finite source size effects, which can
be significant for FFPs. We find that the global ground-based I-band yield over
a central 200 deg^2 region covering the Galactic centre ranges from 20
Earth-mass FFPs year^-1 up to 3,500 year^-1 for Jupiter FFPs in the limit of
100% detection efficiency, and almost an order of magnitude larger for a K-band
survey. For ground-based surveys we find that the inclusion of finite source
and the unresolved background reveals a mass-dependent variation in the spatial
distribution of FFPs. For a space-based H-band covering 2 deg^2, the yield
depends on the target field but maximizes close to the Galactic centre with
around 76 Earth through to 1,700 Jupiter FFPs year^-1. For near-IR space-based
surveys the spatial distribution of FFPs is found to be largely insensitive to
the FFP mass scale.


title:
Numerics for the spin orbit equation of Makarov with constant
  eccentricity

abstract:
  We present an algorithm for the rapid numerical integration of a
time-periodic ODE with a small dissipation term that is $C^1$ in the velocity.
Such an ODE arises as a model of spin-orbit coupling in a star/planet system,
and the motivation for devising a fast algorithm for its solution comes from
the desire to estimate probability of capture in various solutions, via Monte
Carlo simulation: the integration times are very long, since we are interested
in phenomena occurring on times similar to the formation time of the planets.
The proposed algorithm is based on the High-order Euler Method (HEM) which was
described in~\cite{hem}, and it requires computer algebra to set up the code
for its implementation. The pay-off is an overall increase in speed by a factor
of about $7.5$ compared to standard numerical methods. Means for accelerating
the purely numerical computation are also discussed


title: Parities on 2-knots and 2-links

abstract:
  2-dimensional knots and links are studied in the article. The notion of
parity is introduced via techniques similar to the ones used by the second
named author in 1-dimensional case. By using parity new invariants are
constructed and known invariants are refined.


title:
A New Currency of the Future: The Novel Commodity Money with Attenuation
  Coefficient Based on the Logistics Cost of Anchor

abstract:
  In this paper, we reveal the attenuation mechanism of anchor of the commodity
money from the perspective of logistics warehousing costs, and propose a novel
Decayed Commodity Money (DCM) for the store of value across time and space.
Considering the logistics cost of commodity warehousing by the third financial
institution such as London Metal Exchange, we can award the difference between
the original and the residual value of the anchor to the financial institution.
This type of currency has the characteristic of self-decaying value over time.
Therefore DCM has the advantages of both the commodity money which has the
function of preserving wealth and credit currency without the logistics cost.
In addition, DCM can also avoid the defects that precious metal money is
hoarded by market and credit currency often leads to excessive liquidity. DCM
is also different from virtual currency, such as bitcoin, which does not have a
corresponding commodity anchor. As a conclusion, DCM can provide a new way of
storing wealth for nations, corporations and individuals effectively.


title:
Garnet-free optical circulators monolithically integrated on spatially
  modified III-V quantum wells

abstract:
  Optical circulators are indispensable components in photonic networks that
are aimed to route information in a unidirectional way among their N-ports1,2.
In general, these devices rely on magneto-optical garnets3 with appreciable
Verdet constants that are utilized in conjunction with other elements like
permanent magnets, wave-plates, birefringent crystals and/or beam splitters.
Consequently, these arrangements are typically bulky and hence not conducive to
on-chip photonic integration4-6. Of interest would be to devise strategies
through which miniaturized optical circulators can be monolithically fabricated
on light-emitting semiconductor platforms by solely relying on physical
properties that are indigenous to the material itself. By exploiting the
interplay between non-Hermiticity and nonlinearity, here we demonstrate a new
class of chip-scale circulators on spatially modified III-V quantum well
systems. These garnet-free unidirectional structures are broadband (over 2.5
THz) at 1550 nm, effectively loss-free, color-preserving, and in
proof-of-principle demonstrations have provided 23 dB isolation when used under
pulsed-mode conditions at milliwatt (mW) power levels.


title:
A segmental framework for fully-unsupervised large-vocabulary speech
  recognition

abstract:
  Zero-resource speech technology is a growing research area that aims to
develop methods for speech processing in the absence of transcriptions,
lexicons, or language modelling text. Early term discovery systems focused on
identifying isolated recurring patterns in a corpus, while more recent
full-coverage systems attempt to completely segment and cluster the audio into
word-like units---effectively performing unsupervised speech recognition. This
article presents the first attempt we are aware of to apply such a system to
large-vocabulary multi-speaker data. Our system uses a Bayesian modelling
framework with segmental word representations: each word segment is represented
as a fixed-dimensional acoustic embedding obtained by mapping the sequence of
feature frames to a single embedding vector. We compare our system on English
and Xitsonga datasets to state-of-the-art baselines, using a variety of
measures including word error rate (obtained by mapping the unsupervised output
to ground truth transcriptions). Very high word error rates are reported---in
the order of 70--80% for speaker-dependent and 80--95% for speaker-independent
systems---highlighting the difficulty of this task. Nevertheless, in terms of
cluster quality and word segmentation metrics, we show that by imposing a
consistent top-down segmentation while also using bottom-up knowledge from
detected syllable boundaries, both single-speaker and multi-speaker versions of
our system outperform a purely bottom-up single-speaker syllable-based
approach. We also show that the discovered clusters can be made less speaker-
and gender-specific by using an unsupervised autoencoder-like feature extractor
to learn better frame-level features (prior to embedding). Our system's
discovered clusters are still less pure than those of unsupervised term
discovery systems, but provide far greater coverage.


title: The effective exponent gamma(Q) and the slope of the beta function

abstract:
  The slope of the beta function at a fixed point is commonly thought to be RG
invariant and to be the critical exponent gamma* that governs the approach of
any physical quantity R to its fixed-point limit: R*-R proportional to
Q^gamma*. Chyla has shown that this is not quite true. Here we define a proper
RG invariant, the "effective exponent" gamma(Q), whose fixed-point limit is the
true gamma*.


title:
Relieving Geometrical frustration through doping in the
  Dy$_{1-x}$Ca$_{x}$BaCo$_{4}$O$_{7}$ Swedenborgites

abstract:
  The geometrically frustrated antiferromagnetic Swedenborgite
DyBaCo$_{4}$O$_{7}$ is investigated by a combination of xray diffraction,
magnetization and dielectric measurements. Systematic doping in the series
Dy$_{1-x}$Ca$_{x}$BaCo$_{4}$O$_{7}$ causes a lifting of the geometrical
frustration resulting in a structural transition from a Trigonal P31c to an
orthorhombic Pbn2$_{1 }$ symmetry at $x=0.4$. This structural transition can
also be accessed as a function of temperature, and all our orthorhombic
specimens exhibit this transition at elevated temperatures. In line with
previous reports, the temperature at which this structural transition occurs
scales linearly with the mean ionic radii of the $A$ site ion. However,
CaBaCo$_{4}$O$_{7}$ which has an equal number of Co${^{2+}}$ and Co${^{3+}}$
ions clearly violates this quasilinear relationship, indicating that charge
ordering could also play a critical role in stabilizing the orthorhombic
distortion in this system. Using thermoremanent magnetization measurements to
circumvent the problem of the large paramagnetic background arising from
Dy${^{3+}}$ ions, we chart out the phase diagram of the
Dy$_{1-x}$Ca$_{x}$BaCo$_{4}$O$_{7}$ series.


title: Anisotropic Optical Properties of Layered Germanium Sulfide

abstract:
  Two-dimensional (2D) layered materials, transition metal dichalcogenides and
black phosphorus, have attracted much interest from the viewpoints of
fundamental physics and device applications. The establishment of new
functionalities in anisotropic layered 2D materials is a challenging but
rewarding frontier, owing to their remarkable optical properties and prospects
for new devices. Here, we report the anisotropic optical properties of layered
2D monochalcogenide of germanium sulfide (GeS). Three Raman scattering peaks
corresponding to the B3g, A1g, and A2g modes with strong polarization
dependence are demonstrated in the GeS flakes, which validates polarized Raman
spectroscopy as an effective method for identifying the crystal orientation of
anisotropic layered GeS. Photoluminescence (PL) is observed with a peak at
around 1.66 eV that originates from the direct optical transition in GeS at
room temperature. Moreover, determination of the polarization dependent
characteristics of the PL and absorption reveals an anisotropic optical
transition near the band edge of GeS, which is also supported by the density
functional theory calculations. This anisotropic layered GeS presents the
opportunities for the discovery of new physical phenomena and will find
applications that exploit its anisotropic properties.


title: The Embedding of Gauged STU Supergravity in Eleven Dimensions

abstract:
  The consistency of the embedding of four-dimensional SO(8) gauged N=8
supergravity into eleven-dimensional supergravity, where the internal
directions are compactified on a seven-sphere, was established by de Wit and
Nicolai in the 1980s. The reduction ansatz for the eleven-dimensional metric,
and for some of the components of the 4-form field strength, were found at that
time, and recently the complete expression for the 4-form reduction has been
obtained. The expressions are quite complicated, and in many practical
applications it would be sufficient to know the ansatz for a subset of the
four-dimensional fields. In this paper, we obtain explicit expressions for the
embedding of the truncation of the full N=8 gauged theory to the N=2 gauged STU
supergravity. This corresponds, in the bosonic sector, to a consistent
truncation of the N=8 supergravity fields to those that are singlets under the
U(1)^4 Cartan subalgebra of SO(8). This truncation to STU supergravity, which
comprises N=2 supergravity coupled to three vector multiplets, suffices, for
example, for lifting the general 8-charge asymptotically-AdS rotating black
holes to eleven dimensions. We also give two distinct further truncations to
N=2 supergravities coupled to single vector multiplets.


title: Photo-enhanced magnetization in Fe-doped ZnO nanowires

abstract:
  An emerging branch of electronics, the optospintronics, would be highly
boosted if the control of magnetic order by light is implemented in magnetic
semiconductors nanostructures being compatible with the actual technology. Here
we show that the ferromagnetic magnetization of low Fe-doped ZnO nanowires
prepared by carbothermal process is enhanced under illumination up to
temperatures slightly below room temperature. This enhancement is related to
the existence of an oxygen vacancy V$_{\rm O}$ in the neighbouring of an
antiferromagnetic superexchange Fe$^{3+}$-Fe$^{3+}$ pair. Under illumination
the V$_{\rm O}$ is ionized to V$_{\rm O}^+$ giving an electron to a close
Fe$^{3+}$ ion from the antiferromagnetic pair. This light excited electron
transition allows the transition of Fe$^{3+}$ to Fe$^{2+}$ forming stable
ferromagnetic double exchange pairs, increasing the total magnetization. The
results here presented indicate an efficient way to influence the magnetic
properties of ZnO based nanostructures by light illumination at high
temperatures.


title: Statistics of topological RNA structures

abstract:
  In this paper we study properties of topological RNA structures, i.e.~RNA
contact structures with cross-serial interactions that are filtered by their
topological genus. RNA secondary structures within this framework are
topological structures having genus zero. We derive a new bivariate generating
function whose singular expansion allows us to analyze the distributions of
arcs, stacks, hairpin- , interior- and multi-loops. We then extend this
analysis to H-type pseudoknots, kissing hairpins as well as $3$-knots and
compute their respective expectation values. Finally we discuss our results and
put them into context with data obtained by uniform sampling structures of
fixed genus.


title: Hyperbolic Metamaterial Nano-Resonators Make Poor Single Photon Sources

abstract:
  We study the optical properties of quantum dipole emitters coupled to
hyperbolic metamaterial nano-resonators using a semi-analytical quasinormal
mode approach. We show that coupling to metamaterial nano-resonators can lead
to significant Purcell enhancements that are nearly an order of magnitude
larger than those of plasmonic resonators with comparable geometry. However,
the associated single photon output $\beta$-factors are extremely low (around
10$\%$), far smaller than those of comparable sized metallic resonators
(70$\%$). Using a quasinormal mode expansion of the photon Green function, we
describe how the low $\beta$-factors are due to increased Ohmic quenching
arising from redshifted resonances, larger quality factors, and stronger
confinement of light within the metal. In contrast to current wisdom, these
results suggest that hyperbolic metamaterial nano-structures make poor choices
for single photon sources.


title: Matching polytons

abstract:
  Hladky, Hu, and Piguet [Tilings in graphons, preprint] introduced the notions
of matching and fractional vertex covers in graphons. These are counterparts to
the corresponding notions in finite graphs.
  Combinatorial optimization studies the structure of the matching polytope and
the fractional vertex cover polytope of a graph. Here, in analogy, we initiate
the study of the structure of the set of all matchings and of all fractional
vertex covers in a graphon. We call these sets the matching polyton and the
fractional vertex cover polyton.
  We also study properties of matching polytons and fractional vertex cover
polytons along convergent sequences of graphons.
  As an auxiliary tool of independent interest, we prove that a graphon is
$r$-partite if and only if it contains no graph of chromatic number $r+1$. This
in turn gives a characterization of bipartite graphons as those having a
symmetric spectrum.


title:
Dealing with a large number of classes -- Likelihood, Discrimination or
  Ranking?

abstract:
  We consider training probabilistic classifiers in the case of a large number
of classes. The number of classes is assumed too large to perform exact
normalisation over all classes. To account for this we consider a simple
approach that directly approximates the likelihood. We show that this simple
approach works well on toy problems and is competitive with recently introduced
alternative non-likelihood based approximations. Furthermore, we relate this
approach to a simple ranking objective. This leads us to suggest a specific
setting for the optimal threshold in the ranking objective.


title:
The Australian Space Eye: studying the history of galaxy formation with
  a CubeSat

abstract:
  The Australian Space Eye is a proposed astronomical telescope based on a 6U
CubeSat platform. The Space Eye will exploit the low level of systematic errors
achievable with a small space based telescope to enable high accuracy
measurements of the optical extragalactic background light and low surface
brightness emission around nearby galaxies. This project is also a demonstrator
for several technologies with general applicability to astronomical
observations from nanosatellites. Space Eye is based around a 90 mm aperture
clear aperture all refractive telescope for broadband wide field imaging in the
i and z bands.


title:
An Approach for Parallel Genetic Algorithms in the Cloud using Software
  Containers

abstract:
  Genetic Algorithms (GAs) are a powerful technique to address hard
optimisation problems. However, scalability issues might prevent them from
being applied to real-world problems. Exploiting parallel GAs in the cloud
might be an affordable approach to get time efficient solutions that benefit of
the appealing features of the cloud, such as scalability, reliability,
fault-tolerance and cost-effectiveness. Nevertheless, distributed computation
is very prone to cause considerable overhead for communication and making GAs
distributed in an on-demand fashion is not trivial. Aiming to keep under
control the communication overhead and support GAs developers in the
construction and deployment of parallel GAs in the cloud, in this paper we
propose an approach to distribute GAs using the global parallelisation model,
exploiting software containers and their cloud orchestration. We also devised a
conceptual workflow covering each cloud GAs distribution phase, from resources
allocation to actual deployment and execution, in a DevOps fashion.


title: Towards stationary time-vertex signal processing

abstract:
  Graph-based methods for signal processing have shown promise for the analysis
of data exhibiting irregular structure, such as those found in social,
transportation, and sensor networks. Yet, though these systems are often
dynamic, state-of-the-art methods for signal processing on graphs ignore the
dimension of time, treating successive graph signals independently or taking a
global average. To address this shortcoming, this paper considers the
statistical analysis of time-varying graph signals. We introduce a novel
definition of joint (time-vertex) stationarity, which generalizes the classical
definition of time stationarity and the more recent definition appropriate for
graphs. Joint stationarity gives rise to a scalable Wiener optimization
framework for joint denoising, semi-supervised learning, or more generally
inversing a linear operator, that is provably optimal. Experimental results on
real weather data demonstrate that taking into account graph and time
dimensions jointly can yield significant accuracy improvements in the
reconstruction effort.


title: Strong Gravity Approach to QCD and General Relativity

abstract:
  A systematic study of the Weyl-type / Yang-Mills-type action possessing local
conformal invariance and quadratic curvature is undertaken. The dynamical
breaking of this conformal invariance / scale invariance induces general
relativity (GR) as an effective long distance limit of the theory. We prove
that the corresponding field equations of the theory have the linearly rising
potential, which naturally possesses asymptotic freedom and color confinement
properties of quantum chromodynamics (QCD). Solutions to the neutrino mass and
dark energy problems come as free gifts of this formulation. This approach
provides a strong gravity basis for the unification of quantum Yang-Mills
theory (QYMT) with Einstein GR.


title: Information, uncertainty and holographic action

abstract:
  In this short note we show through simple derivation the explicit relation
between information flow and the theories of the emergence of space-time and
gravity, specifically for Newton's second law of motion. Next, in a rather
straightforward derivation the Heisenberg uncertainty relation is uncovered
from the universal bound on information flow. A relation between the universal
bound on information flow and the change in bulk action is also shown to exist.


title: Recursive Distinctioning

abstract:
  Recursive distinctioning (RD) is a name coined by Joel Isaacson in his
original patent document describing how fundamental patterns of process arise
from the systematic application of operations of distinction and description
upon themselves. Recursive distinctioning means just what it says. A pattern of
distinctions is given in a space based on a graphical structure (such as a line
of print or a planar lattice or given graph). Each node of the graph is
occupied by a letter from some arbitrary alphabet. A specialized alphabet is
given that can indicate distinctions about neighbors of a given node. The
neighbors of a node are all nodes that are connected to the given node by edges
in the graph. The letters in the specialized alphabet (call it SA) are used to
describe the states of the letters in the given graph and at each stage in the
recursion, letters in SA are written at all nodes in the graph, describing its
previous state. The recursive structure that results from the iteration of
descriptions is called recursive distinctioning.


title: Mass, zero mass and ... nophysics

abstract:
  In this paper we demonstrate that massless particles cannot be considered as
limiting case of massive particles. Instead, the usual symmetry structure based
on semisimple groups like $U(1)$, $SU(2)$ and $SU(3)$ has to be replaced by
less usual solvable groups like the minimal nonabelian group ${\rm sol}_2$.
Starting from the proper orthochronous Lorentz group ${\rm Lor}_{1,3}$ we
extend Wigner's little group by an additional generator, obtaining the maximal
solvable or Borel subgroup ${\rm Bor}_{1,3}$ which is equivalent to the
Kronecker sum of two copies of ${\rm sol}_2$, telling something about the
helicity of particle and antiparticle states.


title: An Improved Cosmological Model

abstract:
  We study a class of non-local, action-based, and purely gravitational models.
These models seek to describe a cosmology in which inflation is driven by a
large, bare cosmological constant that is screened by the self-gravitation
between the soft gravitons that inflation rips from the vacuum. Inflation ends
with the universe poised on the verge of gravitational collapse, in an
oscillating phase of expansion and contraction that should lead to rapid
reheating when matter is included. After the attainment of a hot, dense
universe the nonlocal screening terms become constant as the universe evolves
through a conventional phase of radiation domination. The onset of matter
domination triggers a much smaller anti-screening effect that could explain the
current phase of acceleration.


title:
Breaking Be: a sterile neutrino solution to the cosmological lithium
  problem

abstract:
  The possibility that the so-called "lithium problem", i.e. the disagreement
between the theoretical abundance predicted for primordial $^7$Li assuming
standard nucleosynthesis and the value inferred from astrophysical
measurements, can be solved through a non-thermal BBN mechanism has been
investigated by several authors. In particular, it has been shown that the
decay of a MeV-mass particle, like, e.g., a sterile neutrino, decaying after
BBN not only solves the lithium problem, but also satisfies cosmological and
laboratory bounds, making such a scenario worth to be investigated in further
detail. In this paper, we constrain the parameters of the model with the
combination of current data, including Planck 2015 measurements of temperature
and polarization anisotropies of the CMB, FIRAS limits on spectral distortions,
astrophysical measurements of primordial abundances and laboratory constraints.
We find that a sterile neutrino with mass $M_S=4.35_{-0.17}^{+0.13}\,MeV$ (at
$95\%$ c.l.), a decay time $\tau_S=1.8_{-1.3}^{+2.5}\cdot 10^5\,s$ (at $95\%$
c.l.) and an initial density $\bar{n}_S/\bar{n}_{cmb}=1.7_{-0.6}^{+3.5}\cdot
10^{-4}$ (at $95\%$ c.l.) in units of the number density of CMB photons,
perfectly accounts for the difference between predicted and observed $^7$Li
primordial abundance. This model also predicts an increase of the effective
number of relativistic degrees of freedom at the time of CMB decoupling $\Delta
N_{eff}^{cmb}\equiv N_{eff}^{cmb}-3.046=0.34_{-0.14}^{+0.16}$ at $95\%$ c.l..
The required abundance of sterile neutrinos is incompatible with the standard
thermal history of the Universe, but could be realized in a low reheating
temperature scenario. We provide forecasts for future experiments finding that
the combination of measurements from the COrE+ and PIXIE missions will allow to
significantly reduce the permitted region for the sterile lifetime and density.


title: Sparse pseudoinverses via LP and SDP relaxations of Moore-Penrose

abstract:
  Pseudoinverses are ubiquitous tools for handling over- and under-determined
systems of equations. For computational efficiency, sparse pseudoinverses are
desirable. Recently, sparse left and right pseudoinverses were introduced,
using 1-norm minimization and linear programming. We introduce several new
sparse pseudoinverses by developing linear and semi-definite programming
relaxations of the well-known Moore-Penrose properties.


title:
Permanent Underdetermination from Approximate Empirical Equivalence in
  Field Theory: Massless and Massive Scalar Gravity, Neutrino, Electromagnetic,
  Yang-Mills and Gravitational Theories

abstract:
  Classical and quantum field theory provide not only realistic examples of
extant notions of empirical equivalence, but also new notions of empirical
equivalence, both modal and occurrent. A simple but modern gravitational case
goes back to the 1890s, but there has been apparently total neglect of the
simplest relativistic analog, with the result that an erroneous claim has taken
root that Special Relativity could not have accommodated gravity even if there
were no bending of light. The fairly recent acceptance of nonzero neutrino
masses shows that widely neglected possibilities for nonzero particle masses
have sometimes been vindicated. In the electromagnetic case, there is permanent
underdetermination at the classical and quantum levels between Maxwell's theory
and the one-parameter family of Proca's electromagnetisms with massive photons,
which approximate Maxwell's theory in the limit of zero photon mass. While
Yang-Mills theories display similar approximate equivalence classically,
quantization typically breaks this equivalence. A possible exception, including
unified electroweak theory, might permit a mass term for the photons but not
the Yang-Mills vector bosons. Underdetermination between massive and massless
(Einstein) gravity even at the classical level is subject to contemporary
controversy.


title: Multi-field inflation and cosmological perturbations

abstract:
  We provide a concise review on multi-field inflation and cosmological
perturbations. We discuss convenient and physically meaningful bases in terms
of which perturbations can be systematically studied. We give formal accounts
on the gauge fixing conditions and present the perturbation action in two
gauges. We also briefly review non-linear perturbations.


title: Smoothed Particle Magnetohydrodynamics: A State of the Union

abstract:
  Obtaining a stable magnetohydrodynamical (MHD) formalism in SPH - i.e.
smoothed particle magnetohydrodynamics (SPMHD) - has proven remarkably
difficult. To implement MHD requires two steps: a modification to the momentum
equation and an induction equation, and both present challenges. We first
provide an overview of how SPMHD is implemented, and then discuss how this
implementation fails and the limitation of various corrective methods - with
particular reference to the effects of particle disorder. Although there are
many problems for which, with careful choice of corrective measures, good
results can be obtained, we then show that, at the very limits of the state of
the art, the ability to perform stable MHD calculations in SPH is curtailed by
numerical issues.


title: Some comments on the reliability of NOAA's Storm Events Database

abstract:
  Storms and other severe weather events can result in fatalities, injuries,
and property damage. Therefore, preventing such outcomes to the extent possible
is a key concern, and the scientific community faces an increasing demand for
regularly updated appraisals of evolving climate conditions and extreme
weather. NOAA's Storm Events Database is undoubtedly an invaluable resource to
the general public, to the professional, and to the researcher. Due to such
importance, the primary objective of this study was to explore this database
and get clues about its reliability. A complete investigation of the damage
estimates, injuries or fatalities figures is unfeasible due to the extension of
the database. However, an exploratory data analysis with the resources of the R
statistical data analysis language found that damage reports are missing in
more than half of the records, that part of the damage values are incorrect,
and that, despite all efforts of standardizations, non-standard event type
names are still finding their way into the database. These few results are
enough to demonstrate that the database suffers from incompleteness and
inconsistencies and should not be used without taking reservations and
appropriate precautions before advancing any inferences from the data.


title: Scaling Bounded Model Checking By Transforming Programs With Arrays

abstract:
  Bounded Model Checking is one the most successful techniques for finding bugs
in program. However, model checkers are resource hungry and are often unable to
verify programs with loops iterating over large arrays.We present a
transformation that enables bounded model checkers to verify a certain class of
array properties. Our technique transforms an array-manipulating (ANSI-C)
program to an array-free and loop-free (ANSI-C) program thereby reducing the
resource requirements of a model checker significantly. Model checking of the
transformed program using an off-the-shelf bounded model checker simulates the
loop iterations efficiently. Thus, our transformed program is a sound
abstraction of the original program and is also precise in a large number of
cases - we formally characterize the class of programs for which it is
guaranteed to be precise. We demonstrate the applicability and usefulness of
our technique on both industry code as well as academic benchmarks.


title: Bias Correction in Saupe Tensor Estimation

abstract:
  Estimation of the Saupe tensor is central to the determination of molecular
structures from residual dipolar couplings (RDC) or chemical shift
anisotropies. Assuming a given template structure, the singular value
decomposition (SVD) method proposed in Losonczi et al. 1999 has been used
traditionally to estimate the Saupe tensor. Despite its simplicity, whenever
the template structure has large structural noise, the eigenvalues of the
estimated tensor have a magnitude systematically smaller than their actual
values. This leads to systematic error when calculating the eigenvalue
dependent parameters, magnitude and rhombicity. We propose here a Monte Carlo
simulation method to remove such bias. We further demonstrate the effectiveness
of our method in the setting when the eigenvalue estimates from multiple
template protein fragments are available and their average is used as an
improved eigenvalue estimator. For both synthetic and experimental RDC datasets
of ubiquitin, when using template fragments corrupted by large noise, the
magnitude of our proposed bias-reduced estimator generally reaches at least 90%
of the actual value, whereas the magnitude of SVD estimator can be shrunk below
80% of the true value.


title: On the Spectral Efficiency Limits of an OAM-based Multiplexing Scheme

abstract:
  As reported in several recent publications, a spatial multiplexing involving
the transmission of orthogonal waves carrying Orbital Angular Momentum (OAM) is
unable to provide spectral efficiency improvements with respect to the
conventional techniques. In this work we emphasize how the limits of an OAM
multiple transmission between antenna arrays can be derived from the Shannon
capacity formula, taking as a reference the performance of a multiplexing
method based on the higher-order channel modes. Our approach clearly indicates
that the two techniques offer the same on-axis performance. Conversely, small
misalignments in the arrays positions affect the OAM scheme, highlighting the
greater robustness of a traditional multiplexing method in the context of radio
communications.


title: Computing hypergeometric functions rigorously

abstract:
  We present an efficient implementation of hypergeometric functions in
arbitrary-precision interval arithmetic. The functions ${}_0F_1$, ${}_1F_1$,
${}_2F_1$ and ${}_2F_0$ (or the Kummer $U$-function) are supported for
unrestricted complex parameters and argument, and by extension, we cover
exponential and trigonometric integrals, error functions, Fresnel integrals,
incomplete gamma and beta functions, Bessel functions, Airy functions, Legendre
functions, Jacobi polynomials, complete elliptic integrals, and other special
functions. The output can be used directly for interval computations or to
generate provably correct floating-point approximations in any format.
Performance is competitive with earlier arbitrary-precision software, and
sometimes orders of magnitude faster. We also partially cover the generalized
hypergeometric function ${}_pF_q$ and computation of high-order parameter
derivatives.


title:
Suppression of single cesium atom heating in a microscopic optical
  dipole trap for demonstration of an 852nm triggered single-photon source

abstract:
  We investigate single cesium (Cs) atom heating owing to the momentum
accumulation process induced by the resonant pulsed excitation in a microscopic
optical dipole trap formed by a strongly focused 1064 nm laser beam. The
heating depends on the trap frequency which restricts the maximum repetition
rate of pulsed excitation. We experimentally verify the heating of a single
atom and then demonstrate how to suppress it with an optimized pulsed
excitation/cooling method. The typical trap lifetime of single Cs atom is
extended from 108 +/- 6 us to 2536 +/- 31 ms, and the corresponding number of
excitation increases from ~ 108 to ~ 360000. In applying this faster cooling
method, we use the trapped single Cs atom as a triggered single-photon source
at an excitation repetition rate of 10 MHz. The second-order intensity
correlations of the emitted single photons are characterized by implementing
Hanbury Brown and Twiss setup, and clear anti-bunching effect has been
observed.


title:
Simultaneous Control and Human Feedback in the Training of a Robotic
  Agent with Actor-Critic Reinforcement Learning

abstract:
  This paper contributes a preliminary report on the advantages and
disadvantages of incorporating simultaneous human control and feedback signals
in the training of a reinforcement learning robotic agent. While robotic
human-machine interfaces have become increasingly complex in both form and
function, control remains challenging for users. This has resulted in an
increasing gap between user control approaches and the number of robotic motors
which can be controlled. One way to address this gap is to shift some autonomy
to the robot. Semi-autonomous actions of the robotic agent can then be shaped
by human feedback, simplifying user control. Most prior work on agent shaping
by humans has incorporated training with feedback, or has included indirect
control signals. By contrast, in this paper we explore how a human can provide
concurrent feedback signals and real-time myoelectric control signals to train
a robot's actor-critic reinforcement learning control system. Using both a
physical and a simulated robotic system, we compare training performance on a
simple movement task when reward is derived from the environment, when reward
is provided by the human, and combinations of these two approaches. Our results
indicate that some benefit can be gained with the inclusion of human generated
feedback.


title:
Suppression of compensating native defect formation during semiconductor
  processing via excess carriers

abstract:
  In many semiconductors, compensating defects set doping limits, decrease
carrier mobility, and reduce minority carrier lifetime thus limiting their
utility in devices. Native defects are responsible in many cases, but extrinsic
dopants may also act as their own compensation when occupying an alternate
lattice site. Suppressing the concentrations of compensating defects during
processing close to thermal equilibrium is difficult because formation
enthalpies are lowered as the Fermi level moves towards the majority band edge.
Excess carriers, introduced for example by photogeneration, modify the
formation enthalpy of semiconductor defects and thus can be harnessed during
crystal growth or annealing to suppress such defect populations. Herein we
develop a rigorous and general model for defect formation in the presence of
steady-state excess carrier concentrations by combining the standard
quasi-chemical formalism with a detailed-balance description that is applicable
for any defect state in the bandgap. Considering the quasi-Fermi levels as
chemical potentials, we demonstrate that increasing the minority carrier
concentration increases the formation enthalpy for typical compensating
centers, thus suppressing their formation. This effect is illustrated for the
specific example of native GaSb antisite acceptors in nominally un-doped and
extrinsically n-type doped GaSb. The model also predicts reductions in the
concentration of ionized scattering centers as well as increased mobility.
While our treatment is generalized for excess carrier injection or generation
in semiconductors by any means, we provide a set of guidelines for applying the
concept in photoassisted physical vapor deposition.


title:
Charged Higgs Boson Production at e+e- Colliders in the Complex MSSM: A
  Full One-Loop Analysis

abstract:
  For the search for additional Higgs bosons in the Minimal Supersymmetric
Standard Model (MSSM) as well as for future precision analyses in the Higgs
sector precise knowledge of their production properties is mandatory. We
evaluate the cross sections for the charged Higgs boson production at e+e-
colliders in the MSSM with complex parameters (cMSSM). The evaluation is based
on a full one-loop calculation of the production mechanism e+e- -> H+H- and
e+e- -> H^\pm W^\mp, including soft and hard QED radiation. The dependence of
the Higgs boson production cross sections on the relevant cMSSM parameters is
analyzed numerically. We find sizable contributions to many cross sections.
They are, depending on the production channel, roughly of 5-10% of the
tree-level results, but can go up to 20% or higher. The full one-loop
contributions are important for a future linear e+e- collider such as the ILC
or CLIC.


title:
Non rationalit\'e stable d'hypersurfaces cubiques sur des corps non
  alg\'ebriquement clos

abstract:
  We propose and compare various techiques available to produce smooth cubic
hypersurfaces over a non-algebraically-closed field which have rational points
but which are not stably rational over their ground field.


title: Higher-order Airy scaling in deformed Dyck paths

abstract:
  We introduce a deformed version of Dyck paths (DDP), where additional to the
steps allowed for Dyck paths, 'jumps' orthogonal to the preferred direction of
the path are permitted. We consider the generating function of DDP, weighted
with respect to their half-length, area and number of jumps. This represents
the first example of an exactly solvable lattice path model showing a
higher-order multicritical point. Applying the generalized method of steepest
descents, we see that the associated two-variable scaling function is given by
the logarithmic derivative of a generalized (higher-order) Airy integral.


title: Generalized Continued Logarithms and Related Continued Fractions

abstract:
  We study continued logarithms as introduced by Bill Gosper and studied by J.
Borwein et. al.. After providing an overview of the type I and type II
generalizations of binary continued logarithms introduced by Borwein et. al.,
we focus on a new generalization to an arbitrary integer base $b$. We show that
all of our so-called type III continued logarithms converge and all rational
numbers have finite type III continued logarithms. As with simple continued
fractions, we show that the continued logarithm terms, for almost every real
number, follow a specific distribution. We also generalize Khinchine's constant
from simple continued fractions to continued logarithms, and show that these
logarithmic Khinchine constants have an elementary closed form. Finally, we
show that simple continued fractions are the limiting case of our continued
logarithms, and briefly consider how we could generalize past continued
logarithms.


title: Necessarily transient quantum refrigerator

abstract:
  We show that one can construct a quantum absorption refrigerator that
provides refrigeration only in the transient regime, by using three interacting
qubits, each of which is also interacting with local heat-bath. The machine
either does not provide cooling in the steady state, or the steady state is
achieved after a long time. We propose a canonical form of qubit-bath
interaction parameters that generates transient cooling without steady-state
cooling, and claim that such a phenomenon is generic to small-scale quantum
absorption refrigerators. We also show that it is generically possible to have
fast cooling. We demonstrate our results for two separate models of
thermalization, and show that a transient cooling without steady-state cooling
is associated with generation of negligible, or no bipartite quantum
correlations. For one of the models of thermalization, we find that the minimum
achievable temperature of the refrigerated qubit can remain almost frozen,
i.e., unchanged, for a significant region of the parameter space.


title: Relic neutrino decoupling with flavour oscillations revisited

abstract:
  We study the decoupling process of neutrinos in the early universe in the
presence of three-flavour oscillations. The evolution of the neutrino spectra
is found by solving the corresponding momentum-dependent kinetic equations for
the neutrino density matrix, including for the first time the proper collision
integrals for both diagonal and off-diagonal elements. This improved
calculation modifies the evolution of the off-diagonal elements of the neutrino
density matrix and changes the deviation from equilibrium of the frozen
neutrino spectra. However, it does not vary the contribution of neutrinos to
the cosmological energy density in the form of radiation, usually expressed in
terms of the effective number of neutrinos, N_eff. We find a value of
N_eff=3.045, in agreement with previous theoretical calculations and consistent
with the latest analysis of Planck data. This result does not depend on the
ordering of neutrino masses. We also consider the effect of non-standard
neutrino-electron interactions (NSI), predicted in many theoretical models
where neutrinos acquire mass. For two sets of NSI parameters allowed by present
data, we find that N_eff can be reduced down to 3.040 or enhanced up to 3.059.


title:
Hybrid cluster+RG approach to the theory of phase transitions in
  strongly coupled Landau-Ginzburg-Wilson model

abstract:
  It is argued that cluster methods provide a viable alternative to Wilson's
momentum shell integration technique at the early stage of renormalization in
the field-theoretic models with strongly coupled fields because these methods
allow for systematic accounting of all interactions in the system irrespective
of their strength. These methods, however, are restricted to relatively small
spatial scales, so they ought to be supplemented with more conventional
renormalization-group (RG) techniques to account for large scale correlations.
To fulfil this goal a "layer-cake" renormalization scheme earlier developed for
rotationally symmetric Hamiltonians has been generalized to the lattice case.
The RG technique can be naturally integrated with an appropriately modified
cluster method so that the RG equations were used only in the presence of large
scale fluctuations, while in their absence the approach reduced to a
conventional cluster method. As an illustrative example the simplest
single-site cluster approximation together with the local-potential RG equation
are applied to simple cubic Ising model to calculate several non-universal
quantities such as the magnetization curve, the critical temperature, and some
critical amplitudes. Good agreement with Monte Carlo simulations and series
expansion results was found.


title: Recursive kernel density estimators under missing data

abstract:
  In this paper we propose an automatic bandwidth selection of the recursive
kernel density estimators with missing data in the context of global and local
density estimation. We showed that, using the selected bandwidth and a special
stepsize, the proposed recursive estimators outperformed the nonrecursive one
in terms of estimation error in the case of global estimation. However, the
recursive estimators are much better in terms of computational costs. We
corroborated these theoretical results through simulation studies and on the
simulated data of the Aquitaine cohort of HIV-1 infected patients and on the
coriell cell lines using the chromosome number 11.


title:
Source Regions of the Type II Radio Burst Observed During a CME-CME
  Interaction on 2013 May 22

abstract:
  We report on our study of radio source regions during the type II radio burst
on 2013 May 22 based on direction finding (DF) analysis of the Wind/WAVES and
STEREO/WAVES (SWAVES) radio observations at decameter-hectometric (DH)
wavelengths. The type II emission showed an enhancement that coincided with
interaction of two coronal mass ejections (CMEs) launched in sequence along
closely spaced trajectories. The triangulation of the SWAVES source directions
posited the ecliptic projections of the radio sources near the line connecting
the Sun and the STEREO-A spacecraft. The WAVES and SWAVES source directions
revealed shifts in the latitude of the radio source indicating that the spatial
location of the dominant source of the type II emission varies during the
CME-CME interaction. The WAVES source directions close to 1 MHz frequencies
matched the location of the leading edge of the primary CME seen in the images
of the LASCO/C3 coronagraph. This correspondence of spatial locations at both
wavelengths confirms that the CME-CME interaction region is the source of the
type II enhancement. Comparison of radio and white-light observations also
showed that at lower frequencies scattering significantly affects radio wave
propagation.


title: Quantum-gas microscopes - A new tool for cold-atom quantum simulators

abstract:
  This "Perspectives" paper gives a brief overview of the recent developments
with quantum-gas microscopes and how they can be used to build the next
generation of cold-atom quantum simulators.


title: Toward Word Embedding for Personalized Information Retrieval

abstract:
  This paper presents preliminary works on using Word Embedding (word2vec) for
query expansion in the context of Personalized Information Retrieval.
Traditionally, word embeddings are learned on a general corpus, like Wikipedia.
In this work we try to personalize the word embeddings learning, by achieving
the learning on the user's profile. The word embeddings are then in the same
context than the user interests. Our proposal is evaluated on the CLEF Social
Book Search 2016 collection. The results obtained show that some efforts should
be made in the way to apply Word Embedding in the context of Personalized
Information Retrieval.


title: Smart Grid Security: Threats, Challenges, and Solutions

abstract:
  The cyber-physical nature of the smart grid has rendered it vulnerable to a
multitude of attacks that can occur at its communication, networking, and
physical entry points. Such cyber-physical attacks can have detrimental effects
on the operation of the grid as exemplified by the recent attack which caused a
blackout of the Ukranian power grid. Thus, to properly secure the smart grid,
it is of utmost importance to: a) understand its underlying vulnerabilities and
associated threats, b) quantify their effects, and c) devise appropriate
security solutions. In this paper, the key threats targeting the smart grid are
first exposed while assessing their effects on the operation and stability of
the grid. Then, the challenges involved in understanding these attacks and
devising defense strategies against them are identified. Potential solution
approaches that can help mitigate these threats are then discussed. Last, a
number of mathematical tools that can help in analyzing and implementing
security solutions are introduced. As such, this paper will provide the first
comprehensive overview on smart grid security.


title:
Exact mean integrated squared error and bandwidth selection for kernel
  distribution function estimators

abstract:
  An exact, closed form, and easy to compute expression for the mean integrated
squared error (MISE) of a kernel estimator of a normal mixture cumulative
distribution function is derived for the class of arbitrary order
Gaussian-based kernels. Comparisons are made with MISE of the empirical
distribution function, the infeasible minimum MISE of kernel estimators, and
the asymptotically optimal second order uniform kernel. The results afford
straightforward extensions to other classes of kernel functions and
distributions. The analysis also offers a guide on when to use higher order
kernels in distribution function estimation.
  A simple plug-in method of simultaneously selecting the optimal bandwidth and
kernel order is proposed based on a non-asymptotic approximation of the unknown
distribution by a normal mixture. A simulation study shows that the method
works well in finite samples, thus providing a viable alternative to existing
bandwidth selection procedures.


title: Shadow of a Charged Rotating Black Hole in $f(R)$ Gravity

abstract:
  We study the shadow of a charged rotating black hole in $f(R)$ gravity. This
black hole is characterized by mass, $M$, spin, $a$, electric charge, $Q$ and
$R_{0}$ which is proportional to cosmological constant. We analyze the image of
the black hole's shadow in four types 1) at $r\rightarrow\infty$, 2) at
$r\rightarrow r_{o}$, in vacuum, 3) at $r\rightarrow\infty$, 4) at
$r\rightarrow r_{o}$, for an observer at the presence of plasma. Moreover, we
investigate the effect of spin, charge and modfication of gravity on the shape
of shadow. In addition, we use two observables, the radius $R_{s}$ and the
distortion parameter $\delta_{s}$, characterizing the apparent shape. We show
that for all cases, the shadow becomes smaller with increasing electric charge.
Also, by increasing the rotation parameters, circular symmetry of the image of
black hole's shadow will change. Furthermore, in the presence of plasma, plasma
parameter also effects on size of the shadow.


title: Anisotropic straining of graphene using micropatterned SiN membranes

abstract:
  We use micro-Raman spectroscopy to study strain profiles in graphene
monolayers suspended over SiN membranes micropatterned with holes of
non-circular geometry. We show that a uniform differential pressure load
$\Delta P$ over elliptical regions of free-standing graphene yields measurable
deviations from hydrostatic strain conventionally observed in
radially-symmetric microbubbles. The top hydrostatic strain $\bar{\varepsilon}$
we observe is estimated to be $\approx0.7\%$ for $\Delta P = 1\,{\rm bar}$ in
graphene clamped to elliptical SiN holes with axis $40$ and $20\,{\rm \mu m}$.
In the same configuration, we report a $G_\pm$ splitting of $10\,{\rm cm^{-1}}$
which is in good agreement with the calculated anisotropy $\Delta\varepsilon
\approx 0.6\%$ for our device geometry. Our results are consistent with the
most recent reports on the Gr\"uneisen parameters. Perspectives for the
achievement of arbitrary strain configurations by designing suitable SiN holes
and boundary clamping conditions are discussed.


title: The word entropy of natural languages

abstract:
  The average uncertainty associated with words is an information-theoretic
concept at the heart of quantitative and computational linguistics. The entropy
has been established as a measure of this average uncertainty - also called
average information content. We here use parallel texts of 21 languages to
establish the number of tokens at which word entropies converge to stable
values. These convergence points are then used to select texts from a massively
parallel corpus, and to estimate word entropies across more than 1000
languages. Our results help to establish quantitative language comparisons, to
understand the performance of multilingual translation systems, and to
normalize semantic similarity measures.


title:
On the uniqueness and stability of dictionaries for sparse
  representation of noisy signals

abstract:
  Learning optimal dictionaries for sparse coding has exposed characteristic
sparse features of many natural signals. However, universal guarantees of the
stability of such features in the presence of noise are lacking. Here, we
provide very general conditions guaranteeing when dictionaries yielding the
sparsest encodings are unique and stable with respect to measurement or
modeling error. We demonstrate that some or all original dictionary elements
are recoverable from noisy data even if the dictionary fails to satisfy the
spark condition, its size is overestimated, or only a polynomial number of
distinct sparse supports appear in the data. Importantly, we derive these
guarantees without requiring any constraints on the recovered dictionary beyond
a natural upper bound on its size. Our results also yield an effective
procedure sufficient to affirm if a proposed solution to the dictionary
learning problem is unique within bounds commensurate with the noise. We
suggest applications to data analysis, engineering, and neuroscience and close
with some remaining challenges left open by our work.


title: Second order behavior of the block counting process of beta coalescents

abstract:
  The Beta coalescents are stochastic processes modeling the genealogy of a
population. They appear as the rescaled limits of the genealogical trees of
numerous stochastic population models. In this article, we take interest in the
number of blocs at small times in the Beta coalescent. Berestycki, Berestycki
and Schweinsberg proved a law of large numbers for this quantity. Recently,
Limic and Talarczyk proved that a functional central limit theorem holds as
well. We give here a simple proof for an unidimensional version of this result,
using a coupling between Beta coalescents and continuous-time branching
processes.


title:
Evidence for exotic hadron contributions to $\Lambda_b^0 \to J/\psi p
  \pi^-$ decays

abstract:
  A full amplitude analysis of $\Lambda_b^0 \to J/\psi p \pi^-$ decays is
performed with a data sample acquired with the LHCb detector from 7 and 8 TeV
$pp$ collisions, corresponding to an integrated luminosity of 3 fb$^{-1}$. A
significantly better description of the data is achieved when, in addition to
the previously observed nucleon excitations $N\to p\pi^-$, either the
$P_c(4380)^+$ and $P_c(4450)^+\to J/\psi p$ states, previously observed in
$\Lambda_b^0 \to J/\psi p K^-$ decays, or the $Z_c(4200)^-\to J/\psi \pi^-$
state, previously reported in $B^0 \to J/\psi K^+ \pi^-$ decays, or all three,
are included in the amplitude models. The data support a model containing all
three exotic states, with a significance of more than three standard
deviations. Within uncertainties, the data are consistent with the
$P_c(4380)^+$ and $P_c(4450)^+$ production rates expected from their previous
observation taking account of Cabibbo suppression.


title: Gravitational Wave Polarization Modes in $f(R)$ Theories

abstract:
  Many studies have been carried out in the literature to evaluate the number
of polarization modes of gravitational waves in modified theories, in
particular in $f(R)$ theories. In the latter ones, besides the usual two
transverse-traceless tensor modes present in general relativity, there are two
additional scalar ones: a massive longitudinal mode and a massless transverse
mode (the so-called breathing mode). This last mode has often been overlooked
in the literature, due to the assumption that the application of the Lorenz
gauge implies transverse-traceless wave solutions. We however show that this is
in general not possible and, in particular, that the traceless condition cannot
be imposed due to the fact that we no longer have a Minkowski background
metric. Our findings are in agreement with the results found using the
Newman-Penrose formalism, and thus clarify the inconsistencies found so far in
the literature.


title: DARWIN: towards the ultimate dark matter detector

abstract:
  DARk matter WImp search with liquid xenoN (DARWIN) will be an experiment for
the direct detection of dark matter using a multi-ton liquid xenon time
projection chamber at its core. Its primary goal will be to explore the
experimentally accessible parameter space for Weakly Interacting Massive
Particles (WIMPs) in a wide mass-range, until neutrino interactions with the
target become an irreducible background. The prompt scintillation light and the
charge signals induced by particle interactions in the xenon will be observed
by VUV sensitive, ultra-low background photosensors. Besides its excellent
sensitivity to WIMPs above a mass of 5 GeV/c2, such a detector with its large
mass, low-energy threshold and ultra-low background level will also be
sensitive to other rare interactions. It will search for solar axions, galactic
axion-like particles and the neutrinoless double-beta decay of 136-Xe, as well
as measure the low-energy solar neutrino flux with <1% precision, observe
coherent neutrino-nucleus interactions, and detect galactic supernovae. We
present the concept of the DARWIN detector and discuss its physics reach, the
main sources of backgrounds and the ongoing detector design and R&D efforts.


title:
Ultrafast shift and rectification photocurrents in GaAs quantum wells:
  Excitation intensity dependence and the importance of bandmixing

abstract:
  A microscopic approach that is based on the multisubband semiconductor Bloch
equations formulated in the basis of a 14-band ${\mathbf k} \cdot {\mathbf p}$
model is employed to compute the temporal dynamics of photocurrents in GaAs
quantum wells following the excitation with femtosecond laser pulses. This
approach provides a transparent description of the interband, intersubband, and
intraband excitations, fully includes all resonant as well as off-resonant
excitations, and treats the light-matter interaction non-perturbatively. For
linearly polarized excitations the photocurrents contain contributions from
shift and rectification currents. We numerically compute and analyze these
currents generated by the excitation with femtosecond laser pulses for [110]-
and [111]-oriented GaAs quantum wells. It is shown that the often employed
perturbative $\chi^{(2)}$-approach breaks down for peak fields larger than
about 10~kV/cm and that non-perturbative effects lead to a reduction of the
peak values of the shift and rectification currents and to temporal
oscillations which originate from Rabi flopping. In particular, we find a
complex oscillatory photon energy dependence of the magnitudes of the shift and
rectification currents. Our simulations demonstrate that this dependence is the
result of mixing between the heavy- and light-hole valence bands. This is a
surprising finding since the bandmixing has an even larger influence on the
strength of the photocurrents than the absorption coefficient. For
[110]-oriented GaAs quantum wells the calculated photon energy dependence is
compared to experimental results and a good agreement is obtained which
validates our theoretical approach.


title:
The $L^2$-Alexander invariant is stronger than the genus and the
  simplicial volume

abstract:
  We study how the genus, the simplicial volume and the $L^2$-Alexander
invariant of W. Li and W. Zhang can detect individual knots among all others.
In particular, we use various techniques coming from hyperbolic geometry and
topology to prove that the $L^2$-Alexander invariant contains strictly more
information than the pair (genus, simplicial volume). Along the way we prove
that the $L^2$-Alexander invariant detects the figure-eight knot $4_1$, the
twist knot $5_2$ and an infinite family of cables on the figure-eight knot.


title: Polarization properties of OH emission in planetary nebulae

abstract:
  We present interferometric, full-polarization observations of the four
ground-state transitions of OH, toward five confirmed and one candidate
OH-emitting planetary nebulae (OHPNe). OHPNe are believed to be very young PNe,
and information on their magnetic fields (provided by their polarization) could
be key to understand the early evolution of PNe. We detect significant circular
and linear polarization in four and two objects, respectively. Possible Zeeman
pairs are seen in JaSt 23 and IRAS 17393-2727, resulting in estimates of
magnetic field strengths between 0.8 and 24 mG. We also report the new
detection of OH emission at 1720 MHz toward Vy 2-2, making it the third known
PN with this type of emission. We suggest that younger PNe have spectra
dominated by narrow maser features and higher degrees of polarization.
Shock-excited emission at 1720 MHz seems to be more common in PNe than in early
evolutionary phases, and could be related to equatorial ejections during the
early PN phase.


title:
Explicit high-order noncanonical symplectic algorithms for ideal
  two-fluid systems

abstract:
  An explicit high-order noncanonical symplectic algorithm for ideal two-fluid
systems is developed. The fluid is discretized as particles in the Lagrangian
description, while the electromagnetic fields and internal energy are treated
as discrete differential form fields on a fixed mesh. With the assistance of
Whitney interpolating forms, this scheme preserves the gauge symmetry of the
electromagnetic field, and the pressure field is naturally derived from the
discrete internal energy. The whole system is solved using the Hamiltonian
splitting method discovered by He et al., which was been successfully adopted
in constructing symplectic particle-in-cell schemes. Because of its structure
preserving and explicit nature, this algorithm is especially suitable for
large-scale simulations for physics problems that are multi-scale and require
long-term fidelity and accuracy. The algorithm is verified via two tests:
studies of the dispersion relation of waves in a two-fluid plasma system and
the oscillating two-stream instability.


title: Using Word Embeddings in Twitter Election Classification

abstract:
  Word embeddings and convolutional neural networks (CNN) have attracted
extensive attention in various classification tasks for Twitter, e.g. sentiment
classification. However, the effect of the configuration used to train and
generate the word embeddings on the classification performance has not been
studied in the existing literature. In this paper, using a Twitter election
classification task that aims to detect election-related tweets, we investigate
the impact of the background dataset used to train the embedding models, the
context window size and the dimensionality of word embeddings on the
classification performance. By comparing the classification results of two word
embedding models, which are trained using different background corpora (e.g.
Wikipedia articles and Twitter microposts), we show that the background data
type should align with the Twitter classification dataset to achieve a better
performance. Moreover, by evaluating the results of word embeddings models
trained using various context window sizes and dimensionalities, we found that
large context window and dimension sizes are preferable to improve the
performance. Our experimental results also show that using word embeddings and
CNN leads to statistically significant improvements over various baselines such
as random, SVM with TF-IDF and SVM with word embeddings.


title:
Quantum State Reconstruction of an Oscillator Network in an
  Optomechanical Setting

abstract:
  We introduce a scheme to reconstruct an arbitrary quantum state of a
mechanical oscillator network. We assume that a single element of the network
is coupled to a cavity field via a linearized optomechanical interaction, whose
time dependence is controlled by a classical driving field. By designing a
suitable interaction profile, we show how the statistics of an arbitrary
mechanical quadrature can be encoded in the cavity field, which can then be
measured. We discuss the important special case of Gaussian state
reconstruction, and study numerically the effectiveness of our scheme for a
finite number of measurements. Finally, we speculate on possible routes to
extend our ideas to the regime of single-photon optomechanics.


title: Exact Solutions to Einstein-Maxwell theory on Eguchi-Hanson Space

abstract:
  In this article, we construct explicit analytical exact solutions to the six
and higher dimensional Einstein-Maxwell theory. In all solutions, a subspace of
the metric is the Eguchi-Hanson space where the metric functions are completely
determined in terms of known analytical functions. Moreover, we find the
solutions can be extended to non-stationary exact solutions to Einstein-Maxwell
theory with cosmological constant. We show that the solutions are
asymptotically expanding patches of de-Sitter spacetime.


title: The Instanton-Dyon Liquid Model III: Finite Chemical Potential

abstract:
  We discuss an extension of the instanton-dyon liquid model that includes
light quarks at finite chemical potential in the center symmetric phase. We
develop the model in details for the case of SU_c(2)\times SU_f(2) by mapping
the theory on a 3-dimensional quantum effective theory. We analyze the
different phases in the mean-field approximation. We extend this analysis to
the general case of SU_c(N_c)\times SU_f(N_f) and note that the chiral and
diquark pairings are always comparable.


title: Stochastic solutions of Conformable fractional Cauchy problems

abstract:
  In this paper we give stochastic solutions of conformable fractional Cauchy
problems. The stochastic solutions are obtained by running the processes
corresponding to Cauchy problems with a nonlinear deterministic clock.


title:
Extremes of $\alpha(t)$-Locally stationary Gaussian processes with
  non-constant variances

abstract:
  With motivation from K. D\c{e}bicki and P. Kisowski (2007), in this paper we
derive the exact tail asymptotics of $\alpha(t)$-locally stationary Gaussian
processes with non-constant variance functions. We show that some certain
variance functions lead to qualitatively new results.


title: On the analytic bijections of the rationals in $[0,1]$

abstract:
  We carry out an arithmetical study of analytic functions $f: [0,1] \to [0,1]$
that by restriction induce a bijection $\mathbb{Q} \cap [0,1] \to \mathbb{Q}
\cap [0,1]$. The existence of such functions shows that, unless $f(x)$ has some
additional property of an algebraic nature, very little can be said about the
distribution of rational points on its graph. Some more refined questions
involving heights are also explored.


title:
Dynamical Casimir-Polder force between an excited atom and a conducting
  wall

abstract:
  We consider the dynamical atom-surface Casimir-Polder force in the
non-equilibrium configuration of an atom near a perfectly conducting wall,
initially prepared in an excited state with the field in its vacuum state. We
evaluate the time-dependent Casimir-Polder force on the atom, and find that it
shows an oscillatory behavior from attractive to repulsive both in time and in
space. We also investigate the asymptotic behavior in time of the dynamical
force and of related local field quantities, showing that the static value of
the force, as obtained by a time-independent approach, is recovered for times
much larger than the timescale of the atomic self-dressing, but smaller than
the atomic decay time. We then discuss the evolution of global quantities such
as atomic and field energies, and their asymptotic behavior. We also compare
our results for the dynamical force on the excited atom with analogous results
recently obtained for an initially bare ground-state atom. We show that new
relevant features are obtained in the case of an initially excited atom, for
example much larger values of the dynamical force with respect to the static
one, allowing for an easier way to single-out and observe the dynamical
Casimir-Polder effect.