title:
The ATLAS3D Project -- XXIII. Angular momentum and nuclear surface
  brightness profiles

abstract:
  [Abridged and Edited] We investigate nuclear light profiles in 135 ATLAS3D
galaxies for which the Hubble Space Telescope (HST) imaging is available and
compare them to the large scale kinematics obtained with the SAURON
integral-field spectrograph. Specific angular momentum, lambda_R, correlates
with the shape of nuclear light profiles, where cores are typically found in
slow rotators and core-less galaxies are fast rotators. Cores are found only in
massive galaxies and only in systems with the stellar mass M>8x10^10 Msun.
Based on our sample, we, however, see no evidence for a bimodal distribution of
nuclear slopes. The best predictor for finding a core is based on the stellar
velocity dispersion within an effective radius, sigma_e, and specific angular
momentum, where cores are found for lambda_R<0.25 and sigma_e>160 km/s. We
estimate that only about 10% of nearby early-type galaxies contain cores.
Furthermore, we show that there is a genuine population of fast rotators with
cores. We also show that core fast rotators are morphologically, kinematically
and dynamically different from core slow rotators. The cores of fast rotators
could harbour black holes of similar masses to those in core slow rotators, but
typically more massive than those found in core-less fast rotators. Core-less
galaxies, and especially core-less fast rotators, are under-luminous in the
diffuse X-ray emission, but the presence of a core does not imply high X-ray
luminosities. We postulate a possible population of core-less galaxies among
slow rotators, which can not be explained as face-on discs, but comprise a
genuine sub-population of slow rotators. These galaxies are typically less
massive and flatter than core slow rotators, and show evidence for dynamical
cold structures and exponential photometric components. We discuss possible
processes for formation of cores and their subsequent preservation.


title: Community detection and graph partitioning

abstract:
  Many methods have been proposed for community detection in networks. Some of
the most promising are methods based on statistical inference, which rest on
solid mathematical foundations and return excellent results in practice. In
this paper we show that two of the most widely used inference methods can be
mapped directly onto versions of the standard minimum-cut graph partitioning
problem, which allows us to apply any of the many well-understood partitioning
algorithms to the solution of community detection problems. We illustrate the
approach by adapting the Laplacian spectral partitioning method to perform
community inference, testing the resulting algorithm on a range of examples,
including computer-generated and real-world networks. Both the quality of the
results and the running time rival the best previous methods.


title: Space Decompositions and Solvers for Discontinuous Galerkin Methods

abstract:
  We present a brief overview of the different domain and space decomposition
techniques that enter in developing and analyzing solvers for discontinuous
Galerkin methods. Emphasis is given to the novel and distinct features that
arise when considering DG discretizations over conforming methods. Connections
and differences with the conforming approaches are emphasized.


title:
Noncoherent Trellis Coded Quantization: A Practical Limited Feedback
  Technique for Massive MIMO Systems

abstract:
  Accurate channel state information (CSI) is essential for attaining
beamforming gains in single-user (SU) multiple-input multiple-output (MIMO) and
multiplexing gains in multi-user (MU) MIMO wireless communication systems.
State-of-the-art limited feedback schemes, which rely on pre-defined codebooks
for channel quantization, are only appropriate for a small number of transmit
antennas and low feedback overhead. In order to scale informed transmitter
schemes to emerging massive MIMO systems with a large number of transmit
antennas at the base station, one common approach is to employ time division
duplexing (TDD) and to exploit the implicit feedback obtained from channel
reciprocity. However, most existing cellular deployments are based on frequency
division duplexing (FDD), hence it is of great interest to explore backwards
compatible massive MIMO upgrades of such systems. For a fixed feedback rate per
antenna, the number of codewords for quantizing the channel grows exponentially
with the number of antennas, hence generating feedback based on look-up from a
standard vector quantized codebook does not scale. In this paper, we propose
noncoherent trellis-coded quantization (NTCQ), whose encoding complexity scales
linearly with the number of antennas. The approach exploits the duality between
source encoding in a Grassmannian manifold and noncoherent sequence detection.
Furthermore, since noncoherent detection can be realized near-optimally using a
bank of coherent detectors, we obtain a low-complexity implementation of NTCQ
encoding using an off-the-shelf Viterbi algorithm applied to standard trellis
coded quantization. We also develop advanced NTCQ schemes which utilize various
channel properties such as temporal/spatial correlations. Simulation results
show the proposed NTCQ and its extensions can achieve near-optimal performance
with moderate complexity and feedback overhead.


title:
Estimating network degree distributions under sampling: An inverse
  problem, with applications to monitoring social media networks

abstract:
  Networks are a popular tool for representing elements in a system and their
interconnectedness. Many observed networks can be viewed as only samples of
some true underlying network. Such is frequently the case, for example, in the
monitoring and study of massive, online social networks. We study the problem
of how to estimate the degree distribution - an object of fundamental interest
- of a true underlying network from its sampled network. In particular, we show
that this problem can be formulated as an inverse problem. Playing a key role
in this formulation is a matrix relating the expectation of our sampled degree
distribution to the true underlying degree distribution. Under many network
sampling designs, this matrix can be defined entirely in terms of the design
and is found to be ill-conditioned. As a result, our inverse problem frequently
is ill-posed. Accordingly, we offer a constrained, penalized weighted
least-squares approach to solving this problem. A Monte Carlo variant of
Stein's unbiased risk estimation (SURE) is used to select the penalization
parameter. We explore the behavior of our resulting estimator of network degree
distribution in simulation, using a variety of combinations of network models
and sampling regimes. In addition, we demonstrate the ability of our method to
accurately reconstruct the degree distributions of various sub-communities
within online social networks corresponding to Friendster, Orkut and
LiveJournal. Overall, our results show that the true degree distributions from
both homogeneous and inhomogeneous networks can be recovered with substantially
greater accuracy than reflected in the empirical degree distribution resulting
from the original sampling.


title:
Investigation of 3/2$_2^-$ state of $^{9}$Li nucleus with microscopic
  structure and reaction models

abstract:
  The low-lying states of the $^{9}$Li nucleus are investigated with a unified
framework of microscopic structure and reaction models. In the structure model,
the wave function is fully antisymmetrized and the $^{9}$Li nucleus is
described as an $\alpha$ + $t$ + $n$ + $n$ four-body system, and low-lying
1/2$^{-}$, 3/2$^{-}$, 5/2$^{-}$, and 7/2$^{-}$ states are obtained by the
stochastic multi-configuration mixing method. Using these wave functions, the
quasi-elastic cross section at $E/A$ = 60 MeV and the elastic and inelastic
cross sections at $E/A$ = 50 MeV on the $^{12}$C target are calculated in the
framework of the microscopic coupled channel (MCC) method. The characteristic
inelastic angular distribution is seen in the 3/2$_{2}^{-}$ state, whose
$\alpha+t$ cluster structure and valence neutron configurations are discussed
in detail. We find the possibility of triaxial deformation and mixing of
di-neutron components in the $^{9}$Li nucleus.


title:
Efficient Transmit Beamspace Design for Search-free Based DOA Estimation
  in MIMO Radar

abstract:
  In this paper, we address the problem of transmit beamspace design for
multiple-input multiple-output (MIMO) radar with colocated antennas in
application to direction-of-arrival (DOA) estimation. A new method for
designing the transmit beamspace matrix that enables the use of search-free DOA
estimation techniques at the receiver is introduced. The essence of the
proposed method is to design the transmit beamspace matrix based on minimizing
the difference between a desired transmit beampattern and the actual one under
the constraint of uniform power distribution across the transmit array
elements. The desired transmit beampattern can be of arbitrary shape and is
allowed to consist of one or more spatial sectors. The number of transmit
waveforms is even but otherwise arbitrary. To allow for simple search-free DOA
estimation algorithms at the receive array, the rotational invariance property
is established at the transmit array by imposing a specific structure on the
beamspace matrix. Semi-definite relaxation is used to transform the proposed
formulation into a convex problem that can be solved efficiently. We also
propose a spatial-division based design (SDD) by dividing the spatial domain
into several subsectors and assigning a subset of the transmit beams to each
subsector. The transmit beams associated with each subsector are designed
separately. Simulation results demonstrate the improvement in the DOA
estimation performance offered by using the proposed joint and SDD transmit
beamspace design methods as compared to the traditional MIMO radar technique.


title:
Permutation Meets Parallel Compressed Sensing: How to Relax Restricted
  Isometry Property for 2D Sparse Signals

abstract:
  Traditional compressed sensing considers sampling a 1D signal. For a
multidimensional signal, if reshaped into a vector, the required size of the
sensing matrix becomes dramatically large, which increases the storage and
computational complexity significantly. To solve this problem, we propose to
reshape the multidimensional signal into a 2D signal and sample the 2D signal
using compressed sensing column by column with the same sensing matrix. It is
referred to as parallel compressed sensing, and it has much lower storage and
computational complexity. For a given reconstruction performance of parallel
compressed sensing, if a so-called acceptable permutation is applied to the 2D
signal, we show that the corresponding sensing matrix has a smaller required
order of restricted isometry property condition, and thus, storage and
computation requirements are further lowered. A zigzag-scan-based permutation,
which is shown to be particularly useful for signals satisfying a layer model,
is introduced and investigated. As an application of the parallel compressed
sensing with the zigzag-scan-based permutation, a video compression scheme is
presented. It is shown that the zigzag-scan-based permutation increases the
peak signal-to-noise ratio of reconstructed images and video frames.


title:
Matching on-the-fly in Sequential Experiments for Higher Power and
  Efficiency

abstract:
  We propose a dynamic allocation procedure that increases power and efficiency
when measuring an average treatment effect in sequential randomized trials.
Subjects arrive iteratively and are either randomized or paired via a matching
criterion to a previously randomized subject and administered the alternate
treatment. We develop estimators for the average treatment effect that combine
information from both the matched pairs and unmatched subjects as well as an
exact test. Simulations illustrate the method's higher efficiency and power
over competing allocation procedures in both controlled scenarios and
historical experimental data.


title:
Reducing decision errors in the paired comparison of the diagnostic
  accuracy of screening tests with Gaussian outcomes

abstract:
  Scientists often use a paired comparison of the areas under the receiver
operating characteristic curves to decide which continuous cancer screening
test has the best diagnostic accuracy. In the paired design, all participants
are screened with both tests. Participants with unremarkable screening results
enter a follow-up period. Participants with suspicious screening results and
those who show evidence of disease during follow-up receive the gold standard
test. The remaining participants are classified as non-cases, even though some
may have occult disease. The standard analysis includes all study participants
in the analysis, which can create bias in the estimates of diagnostic accuracy.
If the bias affects the area under the curve for one screening test more than
the other screening test, scientists may make the wrong decision as to which
screening test has better diagnostic accuracy. We describe a weighted maximum
likelihood bias correction method to reduce decision errors. We assessed the
ability of the bias correction method to reduce decision errors via simulation
studies. The simulations compared the Type I error rate and power of the
standard analysis with that of the bias-corrected analysis. The performance of
the bias correction method depends on characteristics of the screening tests
and the disease, and on the percentage of study participants who receive the
gold standard test. In studies with a large amount of bias in the difference in
the full area under the curve, the bias correction method reduces the Type I
error rate and improves power for the correct decision. In order to determine
if bias correction is needed for a specific screening trial, we recommend the
investigator conduct a simulation study using our free software.


title:
High Precision {\it K}-Shell Photoabsorption Cross Sections for Atomic
  Oxygen: Experiment and Theory

abstract:
  Photoabsorption of atomic oxygen in the energy region below the $\rm 1s^{-1}$
threshold in x-ray spectroscopy from {\it Chandra} and {\it XMM-Newton} is
observed in a variety of x-ray binary spectra. Photoabsorption cross sections
determined from an R-matrix method with pseudo-states (RMPS) and new, high
precision measurements from the Advanced Light Source (ALS) are presented.
High-resolution spectroscopy with E/$\Delta$E $\approx$ 4,250 $\pm$ 400 was
obtained for photon energies from 520 eV to 555 eV at an energy resolution of
124 $\pm$ 12 meV FWHM. {\it K}-shell photoabsorption cross-section measurements
were made with a re-analysis of previous experimental data on atomic oxygen at
the ALS. Natural linewidths $\Gamma$ are extracted for the $\rm 1s^{-1}2s^22p^4
(^4P)np ^3P^{\circ}$ and $\rm 1s^{-1}2s^22p^4(^2P)np ~^3P^{\circ}$ Rydberg
resonances series and compared with theoretical predictions. Accurate cross
sections and linewidths are obtained for applications in x-ray astronomy.
Excellent agreement between theory and the ALS measurements is shown which will
have profound implications for the modelling of x-ray spectra and spectral
diagnostics.


title: Non-equilibrium thermal transport in the quantum Ising chain

abstract:
  We consider two quantum Ising chains initially prepared at thermal
equilibrium but with different temperatures and coupled at a given time through
one of their end points. In the long-time limit the system reaches a
non-equilibrium steady state. We discuss properties of this non-equilibrium
steady state, and characterize the convergence to the steady regime. We compute
the mean energy flux through the chain and the large deviation function for the
quantum and thermal fluctuations of this energy transfer.


title: Hadronic-Origin orphan TeV flare from the 1ES 1959+650

abstract:
  The 1ES 1959+650 is a high-peaked BL Lacertae object. On 4th of June, 2002,
it exhibited a strong TeV flare without any low energy counterpart, providing
for the first time an example of an orphan flare from a blazar. Observation of
this orphan flare is in striking disagreement with the predictions of the
leptonic models thus challenging the conventional synchrotron self-Compton
(SSC) interpretation of the TeV emission. Here we propose that, the low energy
tail of the SSC photons in the blazar jet serve as the target for the
Fermi-accelerated high energy protons of energy . 100 TeV, within the jet to
produce the TeV photons through the decay of neutral pions from the delta
resonance. Our model explains very nicely the observed TeV flux from this
orphan flare and we also estimate the high energy neutrino flux from this
flaring event.


title: Mechanical laws of the Rindler horizon

abstract:
  Gravitational perturbations of flat Minkowski space make the Rindler horizon
dynamical: the horizon satisfies mechanical laws analogous to the ones followed
by black holes. We describe the gravitational perturbation of Minkowski space
using perturbative field-theoretical methods. The change in the area of the
Rindler horizon is described in terms of the deflection of light rays by the
gravitational field. The difference between the area of the perturbed and the
unperturbed horizon is related to the energy of matter crossing the horizon. We
derive consistency conditions for the validity of our approximations, and
compare our results to similar ones present in the literature. Finally, we
discuss how this setting can be used in perturbative quantum gravity to extend
the classical mechanical laws to thermodynamic laws, with the entanglement of
field modes across the Rindler horizon providing a notion of thermodynamic
entropy.


title: Robust Logistic Regression using Shift Parameters (Long Version)

abstract:
  Annotation errors can significantly hurt classifier performance, yet datasets
are only growing noisier with the increased use of Amazon Mechanical Turk and
techniques like distant supervision that automatically generate labels. In this
paper, we present a robust extension of logistic regression that incorporates
the possibility of mislabelling directly into the objective. Our model can be
trained through nearly the same means as logistic regression, and retains its
efficiency on high-dimensional datasets. Through named entity recognition
experiments, we demonstrate that our approach can provide a significant
improvement over the standard model when annotation errors are present.


title: Quantum Techniques for Studying Equilibrium in Reaction Networks

abstract:
  Anderson, Craciun, and Kurtz have proved that a stochastically modelled
chemical reaction system with mass-action kinetics admits a stationary
distribution when the deterministic model of the same system with mass-action
kinetics admits an equilibrium solution obeying a certain "complex balance"
condition. Here we present a proof of their theorem using tools from the theory
of second quantization: Fock space, annihilation and creation operators, and
coherent states. This is an example of "stochastic mechanics", where we take
techniques from quantum mechanics and replace amplitudes by probabilities.


title: The one-loop on-shell renormalization of some vertexes in MSSM

abstract:
  The on-shell renormalization scheme for the electroweak theory is well
studied in the standard model(SM), but a consistent on-shell renormalization
scheme for the minimal supersymmetric standard model(MSSM) is still unknown. In
MSSM, we study the on-shell scheme for three vertexes$Z\bar{l^I}l^I,
W^+\bar{\nu^I}l^I $ and $\tilde{L}^*_i\bar{\chi^0_{\alpha}}l^I$ with virtual
SUSY particles (chargino, sneutrino, neutralino and slepton) at one-loop order.
Instead of amplitude of a single triangle diagram, the sum of amplitude of
triangle diagrams belonging to one suit can be renormalized in the on-shell
scheme. One suit points out that the internal virtual particles are consistent.
Zero-momentum scheme is also used for the renormalization. The two schemes can
make the renormalized results decoupled. In MSSM, some special characters of
the on-shell scheme are shown here. This work is propitious to complete the
on-shell renormalization scheme in MSSM.


title:
On the Study of Hyperbolic Triangles and Circles by Hyperbolic
  Barycentric Coordinates in Relativistic Hyperbolic Geometry

abstract:
  Barycentric coordinates are commonly used in Euclidean geometry. Following
the adaptation of barycentric coordinates for use in hyperbolic geometry in
recently published books on analytic hyperbolic geometry, known and novel
results concerning triangles and circles in the hyperbolic geometry of
Lobachevsky and Bolyai are discovered. Among the novel results are the
hyperbolic counterparts of important theorems in Euclidean geometry. These are:
(1) the Inscribed Gyroangle Theorem, (ii) the Gyrotangent-Gyrosecant Theorem,
(iii) the Intersecting Gyrosecants Theorem, and (iv) the Intersecting Gyrochord
Theorem. Here in gyrolanguage, the language of analytic hyperbolic geometry, we
prefix a gyro to any term that describes a concept in Euclidean geometry and in
associative algebra to mean the analogous concept in hyperbolic geometry and
nonassociative algebra. Outstanding examples are {\it gyrogroups} and {\it
gyrovector spaces}, and Einstein addition being both {\it gyrocommutative} and
{\it gyroassociative}. The prefix "gyro" stems from "gyration", which is the
mathematical abstraction of the special relativistic effect known as "Thomas
precession".


title:
Quantum corrections to $AdS_5 \times S^5$ left-invariant superstring
  current algebra

abstract:
  In this work the pure spinor formulation of the superstring is used to study
quantum corrections to the left current OPE algebra of the coset $PSU(2,
2|4)/SO(4, 1) \times SO(5)$ sigma model, which describes the superstring
dynamics in the $AdS_5 \times S^5$ background. In particular, the one loop
corrections to the simple poles of the bosonic currents are computed. Unlike
the case of the double poles, we show that the simple poles suffer corrections,
which are important since the simple poles contribute to the four point
amplitudes. We show that the only contribution to the simple poles comes from
the pure spinor Lorentz currents.


title:
A boundary problem with integral gluing condition for a
  parabolic-hyperbolic equation involving the Caputo fractional derivative

abstract:
  In the present work we investigate the Tricomi problem with integral gluing
condition for parabolic-hyperbolic equation with the Caputo fractional order
derivative. Using the method of energy integrals we prove the uniqueness of the
solution for considered problem. The existence will be proved using methods of
ordinary differential equations, Fredholm integral equations and solution will
be represented in an explicit form.


title:
Life-Add: Lifetime Adjustable Design for WiFi Networks with
  Heterogeneous Energy Supplies

abstract:
  WiFi usage significantly reduces the battery lifetime of handheld devices
such as smartphones and tablets, due to its high energy consumption. In this
paper, we propose "Life-Add": a Lifetime Adjustable design for WiFi networks,
where the devices are powered by battery, electric power, and/or renewable
energy. In Life-Add, a device turns off its radio to save energy when the
channel is sensed to be busy, and sleeps for a random time period before
sensing the channel again. Life-Add carefully controls the devices' average
sleep periods to improve their throughput while satisfying their operation time
requirement. It is proven that Life-Add achieves near-optimal proportional-fair
utility performance for single access point (AP) scenarios. Moreover, Life-Add
alleviates the near-far effect and hidden terminal problem in general multiple
AP scenarios. Our ns-3 simulations show that Life-Add simultaneously improves
the lifetime, throughput, and fairness performance of WiFi networks, and
coexists harmoniously with IEEE 802.11.


title:
Kishimoto's Conjugacy Theorems in simple $C^*$-algebras of tracial rank
  one

abstract:
  Let $A$ be a unital separable simple amenable $C^*$-algebra with finite
tracial rank which satisfies the Universal Coefficient Theorem (UCT). Suppose
$\af$ and $\bt$ are two automorphisms with the Rokhlin property that {induce
the same action on the $K$-theoretical data of $A$.} We show that $\af$ and
$\bt$ are strongly cocycle conjugate and uniformly approximately conjugate,
that is, there exists a sequence of unitaries $\{u_n\}\subset A$ and a sequence
of strongly asymptotically inner automorphisms $\sigma_n$ such that $$ \af={\rm
Ad}\, u_n\circ \sigma_n\circ \bt\circ \sigma_n^{-1}\andeqn
\lim_{n\to\infty}\|u_n-1\|=0, $$ and that the converse holds. {We then give a
$K$-theoretic description as to exactly when $\af$ and $\bt$ are cocycle
conjugate, at least under a mild restriction. Moreover, we show that given any
$K$-theoretical data, there exists an automorphism $\af$ with the Rokhlin
property which has the same $K$-theoretical data.


title: Drag Reduction, from Bending to Pruning

abstract:
  Most plants and benthic organisms have evolved efficient reconfiguration
mechanisms to resist flow-induced loads. These mechanisms can be divided into
bending, in which plants reduce their sail area through elastic deformation,
and pruning, in which the loads are decreased through partial breakage of the
structure. In this work, we show by using idealized models that these two
mechanisms or, in fact, any combination of the two, are equally efficient to
reduce the drag experienced by terrestrial and aquatic vegetation.


title:
Base Station Sleeping and Resource Allocation in Renewable Energy
  Powered Cellular Networks

abstract:
  We consider energy-efficient wireless resource management in cellular
networks where BSs are equipped with energy harvesting devices, using
statistical information for traffic intensity and harvested energy. The problem
is formulated as adapting BSs' on-off states, active resource blocks (e.g.
subcarriers) as well as power allocation to minimize the average grid power
consumption in a given time period while satisfying the users' quality of
service (blocking probability) requirements. It is transformed into an
unconstrained optimization problem to minimize a weighted sum of grid power
consumption and blocking probability. A two-stage dynamic programming (DP)
algorithm is then proposed to solve this optimization problem, by which the
BSs' on-off states are optimized in the first stage, and the active BS's
resource blocks are allocated iteratively in the second stage. Compared with
the optimal joint BSs' on-off states and active resource blocks allocation
algorithm, the proposed algorithm greatly reduces the computational complexity,
while at the same time achieves close to the optimal energy saving performance.


title: The SHER-HIAF Ring Lattice Design

abstract:
  Super Heavy Experimental Ring (SHER) is one of the rings of the next
accelerator complex High Intensity Heavy Ion Accelerator Facility (HIAF) at
IMP[4]. Here, present ideas of the lattice design for the operation of the
large acceptance ring are presented. The SHER ring has to be optimized for
e-cooling and the lattice is designed for different modes. First of all, it is
designed in the so called isochronous mode as time-of-flight mass spectrometer
for short-lived secondary nuclei. Secondly, SHER can also be used to be a
storage ring for collecting and cooling the secondary rare isotope beams from
the transport line. In order to fulfil it's purpose, the ion optics can be set
to different ion optical modes.


title: E-field measurement of pulse line ion accelerator

abstract:
  The E-field of pulse line ion accelerator (PLIA) is unique with high
frequency (~MHz), large magnitude (~MV/m) and limited measuring space (~cm).
The integrated optical E-field sensor (IOES) has remarkable advantages and has
been used for PLIA E-field measurement. Firstly, the transfer function of IOES
has been calibrated to ensure the measurement accuracy. And the time-domain
response illustrates that the sensor has a fast dynamic performance to
effectively follow a 4 ns rising edge. Then, the E-field distribution along the
axis and near the insulator surface of PLIA was measured, showing that the
propagation of E-field is almost lossless and E-field near the insulation
surface is about 1.1 times larger than that along the axis, which is in
accordance with the simulation result.


title:
Optimal Frame Transmission for Scalable Video with Hierarchical
  Prediction Structure

abstract:
  An optimal frame transmission scheme is presented for streaming scalable
video over a link with limited capacity. The objective is to select a
transmission sequence of frames and their transmission schedule such that the
overall video quality is maximized. The problem is solved for two general
classes of hierarchical prediction structures, which include as a special case
the popular dyadic structure. Based on a new characterization of the
interdependence among frames in terms of trees, structural properties of an
optimal transmission schedule are derived. These properties lead to the
development of a jointly optimal frame selection and scheduling algorithm,
which has computational complexity that is quadratic in the number of frames.
Simulation results show that the optimal scheme substantially outperforms three
existing alternatives.


title: Nonlinear magnetotransport in a dc-current-biased graphene

abstract:
  A balance-equation scheme is developed to investigate the magnetotransport in
a dc-current-biased graphene. We examine the Shubnikov-de Haas oscillation
under a nonzero bias current. With an increase in the current density, the
oscillatory differential resistivity exhibits phase inversion, in agreement
with recent experimental observation. In the presence of surface optical
phonons, a second phase inversion may occur at higher dc bias, due to the
reduced influence of electron-heating and the enhanced direct effect of current
on differential magnetoresistivity. We also predict the appearance of
current-induced magnetoresistance oscillation in suspended graphene at lower
magnetic fields and larger current densities. For the graphene mobility
currently available ($\approx 20\,{\rm m^2/Vs}$), the oscillatory behavior may
be somewhat altered by magnetophonon resonance arising from intrinsic acoustic
phonon under finite bias current condition.


title: A time-of-flight system for the external target facility

abstract:
  A time-of-flight system with a plastic scintillator coupled to
photomultipliers is developed for the external target facility (ETF). This
system can satisfy the requirement of an ultrahigh vacuum ($\sim 10^{-9}$
mbar), a high counting rate ($\sim 10^{6}$ particles per second) and a magnetic
field environment. In the beam test experiment, a total time resolution of 580
ps FWHM was obtained for the whole system, and nuclei with a mass of up to 80
could be identified using this system.


title:
Dissociative electron attachment to carbon dioxide via the ^2\Pi_u shape
  resonance

abstract:
  Momentum imaging measurements from two experiments are presented and
interpreted with the aid of new ab initio theoretical calculations to describe
the dissociative electron attachment (DEA) dynamics. We address the problem of
how the 4 eV ^2\Pi_u shape resonance in CO_2 proceeds to dissociate to
CO(^1\Sigma^+) + O^-(^2P) by DEA.


title: Magnetically Defined Qubits on 3D Topological Insulators

abstract:
  We explore potentials that break time-reversal symmetry to confine the
surface states of 3D topological insulators into quantum wires and quantum
dots. A magnetic domain wall on a ferromagnet insulator cap layer provides
interfacial states predicted to show the quantum anomalous Hall effect (QAHE).
Here we show that confinement can also occur at magnetic domain
heterostructures, with states extended in the inner domain, as well as
interfacial QAHE states at the surrounding domain walls. The proposed geometry
allows the isolation of the wire and dot from spurious circumventing surface
states. For the quantum dots we find that highly spin-polarized quantized QAHE
states at the dot edge constitute a promising candidate for quantum computing
qubits.


title: Fine-scale Structures of Flux Ropes Tracked by Erupting Material

abstract:
  We present the Solar Dynamics Observatory observations of two flux ropes
respectively tracked out by material from a surge and a failed filament
eruption on 2012 July 29 and August 04. For the first event, the interaction
between the erupting surge and a loop-shaped filament in the east seems to
"peel off" the filament and add bright mass into the flux rope body. The second
event is associated with a C-class flare that occurs several minutes before the
filament activation. The two flux ropes are respectively composed of 85$\pm$12
and 102$\pm$15 fine-scale structures, with an average width of about
1$\arcsec$.6. Our observations show that two extreme ends of the flux rope are
rooted in the opposite polarity fields and each end is composed of multiple
footpoints (FPs) of the fine-scale structures. The FPs of the fine-scale
structures are located at network magnetic fields, with magnetic fluxes from
5.6$\times10^{18}$ Mx to 8.6$\times10^{19}$ Mx. Moreover, almost half of the
FPs show converging motion of smaller magnetic structures over 10 hr before the
appearance of the flux rope. By calculating the magnetic fields of the FPs, we
deduce that the two flux ropes occupy at least 4.3$\times10^{20}$ Mx and
7.6$\times10^{20}$ Mx magnetic fluxes, respectively.


title: A turnstile mechanism for fronts propagating in fluid flows

abstract:
  We consider the propagation of fronts in a periodically driven flowing
medium. It is shown that the progress of fronts in these systems may be
mediated by a turnstile mechanism akin to that found in chaotic advection. We
first define the modified ("active") turnstile lobes according to the evolution
of point sources across a transport boundary. We then show that the lobe
boundaries may be constructed from stable and unstable \emph{burning invariant
manifolds}---one-way barriers to front propagation analogous to traditional
invariant manifolds for passive advection. Because the burning invariant
manifolds (BIMs) are one-dimensional curves in a three-dimensional ($xy\theta$)
phase space, their projection into $xy$-space exhibits several key differences
from their advective counterparts: (lobe) areas are not preserved, BIMs may
self-intersect, and an intersection between stable and unstable BIMs does not
map to another such intersection. These differences must be accommodated in the
correct construction of the new turnstile. As an application, we consider a
lobe-based treatment protocol for protecting an ocean bay from an invading
algae bloom.


title:
Deformation of a projection in the multipleir algebra and projection
  lifting from the corona algebra of a non-simple C*-algebra

abstract:
  Let $X$ be a unit interval or a unit circle and let $B$ be a
$\sigma_p$-unital, purely infinite, simple $C\sp*$-algebra such that its
multiplier algebra $M(B)$ has real rank zero. Then we determine necessary and
sufficient conditions for a projection in the corona algebra of $C(X)\otimes B$
to be liftable to a projection in the multiplier algebra. This generalizes a
result proved by L. Brown and the author \cite{BL}. The main technical tools
are divided into two parts. The first part is borrowed from the author's
previous paper(JFA 260 (2011)). The second part is a proposition showing that
we can produce a sub-projection, with an arbitrary rank which is prescribed as
K-theoretical data, of a projection or a co-projection in the multiplier
algebra of $C(X)\otimes B$ under a suitable "infinite rank and co-rank"
condition.


title: A normal-pressure MWPC for beam diagnostics at RIBLL2

abstract:
  A normal pressure MWPC for beam diagnostics at RIBLL2 has been developed,
which has a sensitive area of 80 mm$\times$80 mm and consists of three-layer
wire planes. The anode plane is designed with a wider frame to reduce the
discharge and without using protection wires. The detector has been tested with
a $^{55}$Fe X-ray source and a 200 MeV/u $^{12}$C beam from CSRm. A position
resolution better than 250 $\upmu$m along the anode wires and a detection
efficiency higher than 90% have been achieved.


title: Structure and radial equilibrium of filamentary molecular clouds

abstract:
  Recent dust continuum surveys have shown that filamentary structures are
ubiquitous along the Galactic plane. While the study of their global properties
has gained momentum recently, we are still far from fully understanding their
origin and stability. Theories invoking magnetic field have been formulated to
help explain the stability of filaments; however, observations are needed to
test their predictions. In this paper, we investigate the structure and radial
equilibrium of five filamentary molecular clouds with the aim of determining
the role that magnetic field may play. To do this, we use continuum and
molecular line observations to obtain their physical properties (e.g. mass,
temperature and pressure). We find that the filaments have lower lineal masses
compared to their lineal virial masses. Their virial parameters and shape of
their dust continuum emission suggests that these filaments may be confined by
a toroidal dominated magnetic field.


title:
A transition of limiting distributions of large matchings in random
  graphs

abstract:
  We study the asymptotic distribution of the number of matchings of size
$\ell=\ell(n)$ in $G(n,p)$ for a wide range of $p=p(n)\in (0,1)$ and for every
$1\le \ell\le \lfloor n/2\rfloor$. We prove that this distribution changes from
normal to log-normal as $\ell$ increases, and we determine the critical value
of $\ell$, as a function of $n$ and $p$, at which the transition of the
limiting distribution occurs.


title: Analysis of $B_s\to \phi\mu^+\mu^-$ decay within supersymmetry

abstract:
  Motivated by the first measurement on $\mathcal{B}(B_s\to\phi \mu^+\mu^-)$ by
the CDF Collaboration, we study the supersymmetric effects in semi-leptonic
$B_s\to\phi\mu^+\mu^-$ decay. In our evaluations, we analyze the dependences of
the dimuon invariant mass spectrum and the forward-backward asymmetry on
relevant supersymmetric couplings in the MSSM with and without R-parity. The
analyses show the new experimental upper limits of
$\mathcal{B}(B_s\to\mu^+\mu^-)$ from the LHCb Collaboration could further
improve the bounds on sneutrino exchange couplings and $(\delta^u_{LL})_{23}$
as well as $(\delta^d_{LL,RR})_{23}$ mass insertion couplings. In addition,
within the allowed ranges of relevant couplings under the constraints from
$\mathcal{B}(B_s\to\phi \mu^+\mu^-)$, $\mathcal{B}(B\to K^{(*)}\mu^+\mu^-)$ and
$\mathcal{B}(B_s\to \mu^+\mu^-)$, the dimuon forward-backward asymmetry and the
differential dimuon forward-backward asymmetry of $B_s\to\phi\mu^+\mu^-$ are
highly sensitive to the squark exchange contribution and the
$(\delta^u_{LL})_{23}$ mass insertion contribution. The results obtained in
this work will be very useful in searching supersymmetric signal at the LHC.


title: Study on the imaging ability of the 2D neutron detector based on MWPC

abstract:
  A 2D neutron detector based on 3He convertor and MWPC with an active area of
200 mm \times 200 mm has been successfully designed and fabricated. The
detector has been tested with Am/Be neutron source and with collimated neutron
beam with wavelength of {\lambda} = 1.37 {\AA}. A best spatial resolution of
1.18 mm (FWHM) and good linearity were obtained. This is in good agreement with
the theoretical calculations.


title: Double injection in graphene p-i-n structures

abstract:
  We study the processes of the electron and hole injection (double injection)
into the i-region of graphene-layer and multiple graphene-layer p-i-n
structures at the forward bias voltages. The hydrodynamic equations governing
the electron and hole transport in graphene coupled with the two-dimensional
Poisson equation are employed. Using analytical and numerical solutions of the
equations of the model, we calculate the band edge profile, the spatial
distributions of the quasi-Fermi energies, carrier density and velocity, and
the current-voltage characteristics. In particular, we demonstrated that the
electron and hole collisions can strongly affect these distributions. The
obtained results can be used for the realization and optimization of
graphene-based injection terahertz and infrared lasers.


title: A testable scenario of WIMPZILLA with Dark Radiation

abstract:
  As the electromagnetic gauge symmetry makes the electron stable, a new
abelian gauge symmetry may be responsible for the stability of superheavy dark
matter. The gauge boson associated with the new gauge symmetry naturally plays
the role of dark radiation and contributes to the effective number of `neutrino
species', which has been recently measured by Planck. We estimate the
contribution of dark radiation from the radiative decay of a scalar particle
induced by the WIMPZILLA in the loop. The scalar particle may affect the
invisible decay of the Higgs boson by the Higgs portal type coupling.


title:
Legendre transformations and the thermodynamic geometry of 5D black
  holes

abstract:
  This paper studies the thermodynamic properties of the 5D black hole in
Einstein-Gauss-Bonnet gravity from the viewpoint of geometrothermodynamics. It
{is found} that the Legendre invariant metrics of the 5D black {holes} in
Einstein-Yang-Mills-Gauss-Bonnet {theory and} Einstein-Maxwell-Gauss-Bonnet
{theory} reproduce the behavior of the thermodynamic interaction and phase
transition structure of the corresponding black hole configurations
{correctly}. It is shown that they are both curved and {that} the curvature
scalar {provides} information about the phase transition point.


title: Radio frequency spectrum of fermions near a narrow Feshbach resonance

abstract:
  We calculate the radio frequency (RF) spectrum of fermionic atoms near a
narrow Feshbach resonance, explaining observations made in ultracold samples of
$^6\rm{Li}$ [E. L. Hazlett {\it et al.}, Phys. Rev. Lett. {\bf 108}, 045304
(2012)]. We use a two channel resonance model to show that the RF spectrum
contains two peaks. In the wide-resonance limit, nearly all spectral weight
lies in one of these peaks, and typically the second peak is very broad. We
find strong temperature dependence, which can be traced to the energy
dependence of the two-particle scattering. In addition to microscopic
calculations, we use sum rule arguments to find generic features of the
spectrum which are model independent.


title:
Origin of the two-dimensional electron gas at LaAlO3/SrTiO3 interfaces:
  The role of oxygen vacancies and electronic reconstruction

abstract:
  The relative importance of atomic defects and electron transfer in explaining
conductivity at the crystalline LaAlO3/SrTiO3 interface has been a topic of
debate. Metallic interfaces with similar electronic properties produced by
amorphous oxide overlayers on SrTiO3 have called in question the original
polarization catastrophe model. We resolve the issue by a comprehensive
comparison of (100)-oriented SrTiO3 substrates with crystalline and amorphous
overlayers of LaAlO3 of different thicknesses prepared under different oxygen
pressures. For both types of overlayers, there is a critical thickness for the
appearance of conductivity, but its value is always 4 unit cells (around 1.6
nm) for the oxygen-annealed crystalline case, whereas in the amorphous case,
the critical thickness could be varied in the range 0.5 to 6 nm according to
the deposition conditions. Subsequent ion milling of the overlayer restores the
insulating state for the oxygen-annealed crystalline heterostructures but not
for the amorphous ones. Oxygen post-annealing removes the oxygen vacancies, and
the interfaces become insulating in the amorphous case. However, the interfaces
with a crystalline overlayer remain conducting with reduced carrier density.
These results demonstrate that oxygen vacancies are the dominant source of
mobile carriers when the LaAlO3 overlayer is amorphous, while both oxygen
vacancies and polarization catastrophe contribute to the interface conductivity
in unannealed crystalline LaAlO3/SrTiO3 heterostructures, and the polarization
catastrophe alone accounts for the conductivity in oxygen-annealed crystalline
LaAlO3/SrTiO3 heterostructures. Furthermore, we find that the crystallinity of
the LaAlO3 layer is crucial for the polarization catastrophe mechanism in the
case of crystalline LaAlO3 overlayers.


title: PAWL-Forced Simulated Tempering

abstract:
  In this short note, we show how the parallel adaptive Wang-Landau (PAWL)
algorithm of Bornn et al. (2013) can be used to automate and improve simulated
tempering algorithms. While Wang-Landau and other stochastic approximation
methods have frequently been applied within the simulated tempering framework,
this note demonstrates through a simple example the additional improvements
brought about by parallelization, adaptive proposals and automated bin
splitting.


title: Spin-wave nonreciprocity based on interband magnonic transitions

abstract:
  We theoretically demonstrate linear spin-wave nonreciprocity in a Ni80Fe20
nanostripe waveguide, based on interband magnonic transitions induced by a
time-reversal and spatialinversion symmetry breaking magnetic field. An
analytical coupled-mode theory of spin waves, developed to describe the
transitions which are accompanied by simultaneous frequency and wavevector
shifts of the coupled spin waves, is well corroborated by numerical
simulations. Our findings could pave the way for the realization of spin-wave
isolation and the dynamic control of spin-wave propagation in nanoscale
magnonic integrated circuits via an applied magnetic field.


title:
Implications for Utilizing YouTube based Community Interactions for
  Destination Marketing

abstract:
  In recent time, YouTube has evolved into a powerful medium for social
interaction. Utilizing YouTube for enhancing marketing endeavors is a strategy
practiced by marketing professionals across several industries. This paper
rationalizes on the different ways and means of leveraging YouTube-based
platforms for effective destination marketing by the hospitality industry
(hotels). More specifically, the typology of virtual communities is adapted to
evaluate the YouTube platform for effective destination marketing. Comments
made by YouTube users have been subjected to a content analysis and the results
are reported here under the five broad clusters of virtual communities.
Implications for utilizing YouTube-based community interactions for destination
marketing are also highlighted as part of the outcome of this research.


title:
Early thermalization of quark-gluon matter with the elastic scattering
  of ggq and ggqbar

abstract:
  Elastic gluon-gluon-quark (gluon-gluon-antiquark) scattering is studied in
perturbative QCD with 123 Feynman diagrams at the tree level. Individually
squared amplitudes and interference terms of the Feynman diagrams are derived.
With the elastic gluon-gluon-quark scattering and the elastic
gluon-gluon-antiquark scattering transport equations are established. In the
thermalization process of initially created quark-gluon matter, this matter is
governed by elastic 2-to-2 scattering and elastic 3-to-3 scattering. Solutions
of the transport equations show that initially created quark-gluon matter takes
early thermalization, i.e., thermal states are established rapidly. Different
thermalization times of gluon matter and quark matter are obtained.


title:
Loop prolongations and three-cocycles in simulated magnetic fields from
  rotating reference frames

abstract:
  We show that the Wigner-Bargmann program of grounding non-relativistic
quantum mechanics in the unitary projective representations of the Galilei
group can be extended to include all non-inertial reference frames. The key
concept is the \emph{Galilean line group}, the group of transformations that
ties together all accelerating reference frames, and its representations. These
representations are constructed under the natural constraint that they reduce
to the well-known unitary, projective representations of the Galilei group when
the transformations are restricted to inertial reference frames. This
constraint can be accommodated only for a class of representations with a
sufficiently rich cocycle structure. Unlike the projective representations of
the Galilei group, these cocycle representations of the Galilean line group do
not correspond to central extensions of the group. Rather, they correspond to a
class of non-associative extensions, known as \emph{loop prolongations}, that
are determined by three-cocycles. As an application, we show that the phase
shifts due to the rotation of the earth that have been observed in neutron
interferometry experiments and the rotational effects that lead to simulated
magnetic fields in optical lattices can be rigorously derived from the
representations of the loop prolongations of the Galilean line group.


title:
Numerical integration of ordinary differential equations with rapidly
  oscillatory factors

abstract:
  We present a methodology for numerically integrating ordinary differential
equations containing rapidly oscillatory terms. This challenge is distinct from
that for differential equations which have rapidly oscillatory solutions: here
the differential equation itself has the oscillatory terms. Our method
generalises Filon quadrature for integrals, and is analogous to integral
techniques designed to solve stochastic differential equations and, as such, is
applicable to a wide variety of ordinary differential equations with rapidly
oscillating factors. The proposed method flexibly achieves varying levels of
accuracy depending upon the truncation of the expansion of certain integrals.
Users will choose the level of truncation to suit the parameter regime of
interest in their numerical integration.


title:
Estimating Photometric Redshifts of Quasars via K-nearest Neighbor
  Approach Based on Large Survey Databases

abstract:
  We apply one of lazy learning methods named k-nearest neighbor algorithm
(kNN) to estimate the photometric redshifts of quasars, based on various
datasets from the Sloan Digital Sky Survey (SDSS), UKIRT Infrared Deep Sky
Survey (UKIDSS) and Wide-field Infrared Survey Explorer (WISE) (the SDSS
sample, the SDSS-UKIDSS sample, the SDSS-WISE sample and the SDSS-UKIDSS-WISE
sample). The influence of the k value and different input patterns on the
performance of kNN is discussed. kNN arrives at the best performance when k is
different with a special input pattern for a special dataset. The best result
belongs to the SDSS-UKIDSS-WISE sample. The experimental results show that
generally the more information from more bands, the better performance of
photometric redshift estimation with kNN. The results also demonstrate that kNN
using multiband data can effectively solve the catastrophic failure of
photometric redshift estimation, which is met by many machine learning methods.
By comparing the performance of various methods for photometric redshift
estimation of quasars, kNN based on KD-Tree shows its superiority with the best
accuracy for our case.


title:
A Nonlinear Constrained Optimization Framework for Comfortable and
  Customizable Motion Planning of Nonholonomic Mobile Robots - Part I

abstract:
  In this series of papers, we present a motion planning framework for planning
comfortable and customizable motion of nonholonomic mobile robots such as
intelligent wheelchairs and autonomous cars. In this first one we present the
mathematical foundation of our framework.
  The motion of a mobile robot that transports a human should be comfortable
and customizable. We identify several properties that a trajectory must have
for comfort. We model motion discomfort as a weighted cost functional and
define comfortable motion planning as a nonlinear constrained optimization
problem of computing trajectories that minimize this discomfort given the
appropriate boundary conditions and constraints. The optimization problem is
infinite-dimensional and we discretize it using conforming finite elements. We
also outline a method by which different users may customize the motion to
achieve personal comfort.
  There exists significant past work in kinodynamic motion planning, to the
best of our knowledge, our work is the first comprehensive formulation of
kinodynamic motion planning for a nonholonomic mobile robot as a nonlinear
optimization problem that includes all of the following - a careful analysis of
boundary conditions, continuity requirements on trajectory, dynamic
constraints, obstacle avoidance constraints, and a robust numerical
implementation.
  In this paper, we present the mathematical foundation of the motion planning
framework and formulate the full nonlinear constrained optimization problem. We
describe, in brief, the discretization method using finite elements and the
process of computing initial guesses for the optimization problem. Details of
the above two are presented in Part II of the series.


title:
A Nonlinear Constrained Optimization Framework for Comfortable and
  Customizable Motion Planning of Nonholonomic Mobile Robots - Part II

abstract:
  In this series of papers, we present a motion planning framework for planning
comfortable and customizable motion of nonholonomic mobile robots such as
intelligent wheelchairs and autonomous cars. In Part I, we presented the
mathematical foundation of our framework, where we model motion discomfort as a
weighted cost functional and define comfortable motion planning as a nonlinear
constrained optimization problem of computing trajectories that minimize this
discomfort given the appropriate boundary conditions and constraints.
  In this paper, we discretize the infinite-dimensional optimization problem
using conforming finite elements. We describe shape functions to handle
different kinds of boundary conditions and the choice of unknowns to obtain a
sparse Hessian matrix. We also describe in detail how any trajectory
computation problem can have infinitely many locally optimal solutions and our
method of handling them. Additionally, since we have a nonlinear and
constrained problem, computation of high quality initial guesses is crucial for
efficient solution. We show how to compute them.


title: Geometrical Excess Entropy Production in Nonequilibrium Quantum Systems

abstract:
  For open systems described by the quantum Markovian master equation, we study
a possible extension of the Clausius equality to quasistatic operations between
nonequilibrium steady states (NESSs). We investigate the excess heat divided by
temperature (i.e., excess entropy production) which is transferred into the
system during the operations. We derive a geometrical expression for the excess
entropy production, which is analogous to the Berry phase in unitary evolution.
Our result implies that in general one cannot define a scalar potential whose
difference coincides with the excess entropy production in a thermodynamic
process, and that a vector potential plays a crucial role in the thermodynamics
for NESSs. In the weakly nonequilibrium regime, we show that the geometrical
expression reduces to the extended Clausius equality derived by Saito and
Tasaki (J. Stat. Phys. {\bf 145}, 1275 (2011)). As an example, we investigate a
spinless electron system in quantum dots. We find that one can define a scalar
potential when the parameters of only one of the reservoirs are modified in a
non-interacting system, but this is no longer the case for an interacting
system.


title:
Field-induced spin-structural transition and giant magnetostriction in
  Ising chain $\alpha$-CoV$_2$O$_6$

abstract:
  We have investigated the temperature and magnetic field dependence of
magnetization, specific heat ($C_p$), and relative sample length change
($\Delta L/L_0$) for understanding the field-induced spin-structural change in
quasi-one-dimensional spin chain $\alpha$-CoV$_2$O$_6$ which undergoes
antiferromagnetic (AFM) transition below $T_N$$=$15 K. Analysis of $C_p$($T$)
shows that an effective $S$$=$1/2 Ising state is realized below 20 K, though
the magnetic fluctuations persist well above $T_N$. $C_p$ and the coefficient
of linear thermal expansion ($\alpha$) exhibit strong $H$ dependence in the AFM
state. We also observe a huge positive magnetostriction [$\Delta L$($H$)/$L_0$]
below 20 K which does not show any tendency of saturation up to 9 T. With
increasing field, a sharp and symmetric peak emerges below $T_N$ in both
$C_p$($T$) and $\alpha$($T$) due to field-induced first order
ferrimagnetic/ferromagnetic-paramagnetic transitions. The large value of
magnetostriction below $T_N$ suggests strong spin-lattice coupling in
$\alpha$-CoV$_2$O$_6$.


title: Riemannian and Finslerian spheres with fractal cut loci

abstract:
  The present paper shows that for a given integer k greater than 2 it is
possible to construct an at least k-differentiable Riemannian metric on the
sphere of a certain dimension such that the cut locus of a point of it becomes
a fractal. Moreover, we show that this construction can be extended to the case
of Finsler sphere as well.


title:
Divide and Conquer Kernel Ridge Regression: A Distributed Algorithm with
  Minimax Optimal Rates

abstract:
  We establish optimal convergence rates for a decomposition-based scalable
approach to kernel ridge regression. The method is simple to describe: it
randomly partitions a dataset of size N into m subsets of equal size, computes
an independent kernel ridge regression estimator for each subset, then averages
the local solutions into a global predictor. This partitioning leads to a
substantial reduction in computation time versus the standard approach of
performing kernel ridge regression on all N samples. Our two main theorems
establish that despite the computational speed-up, statistical optimality is
retained: as long as m is not too large, the partition-based estimator achieves
the statistical minimax rate over all estimators using the set of N samples. As
concrete examples, our theory guarantees that the number of processors m may
grow nearly linearly for finite-rank kernels and Gaussian kernels and
polynomially in N for Sobolev spaces, which in turn allows for substantial
reductions in computational cost. We conclude with experiments on both
simulated data and a music-prediction task that complement our theoretical
results, exhibiting the computational and statistical benefits of our approach.


title: Towards Rational Deployment of Multiple Heuristics in A*

abstract:
  The obvious way to use several admissible heuristics in A* is to take their
maximum. In this paper we aim to reduce the time spent on computing heuristics.
We discuss Lazy A*, a variant of A* where heuristics are evaluated lazily: only
when they are essential to a decision to be made in the A* search process. We
present a new rational meta-reasoning based scheme, rational lazy A*, which
decides whether to compute the more expensive heuristics at all, based on a
myopic value of information estimate. Both methods are examined theoretically.
Empirical evaluation on several domains supports the theoretical results, and
shows that lazy A* and rational lazy A* are state-of-the-art heuristic
combination methods.


title: 3D Dirac Electrons on a Cubic Lattice with Noncoplanar Multiple-Q Order

abstract:
  Noncollinear and noncoplanar spin textures in solids manifest themselves not
only in their peculiar magnetism but also in unusual electronic and transport
properties. We here report our theoretical studies of a noncoplanar order on a
simple cubic lattice and its influence on the electronic structure. We show
that a four-sublattice triple-Q order induces three-dimensional massless Dirac
electrons at commensurate electron fillings. The Dirac state is doubly
degenerate, while it splits into a pair of Weyl nodes by lifting the degeneracy
by an external magnetic field; the system is turned into a Weyl semimetal in
applied field. In addition, we point out the triple-Q Hamiltonian in the strong
coupling limit is equivalent to the 3D \pi-flux model relevant to an AIII
topological insulator. We examine the stability of such a triple-Q order in two
fundamental models for correlated electron systems: a Kondo lattice model with
classical localized spins and a periodic Anderson model. For the Kondo lattice
model, performing a variational calculation and Monte Carlo simulation, we show
that the triple-Q order is widely stabilized around 1/4 filling. For the
periodic Anderson model, we also show the stability of the same triple-Q state
by using the mean-field approximation. For both models, the triple-Q order is
widely stabilized via the couplings between conduction electrons and localized
electrons even without any explicit competing magnetic interactions and
geometrical frustration. We also show that the Dirac electrons induce peculiar
surface states: Fermi "arcs" connecting the projected Dirac points, similarly
to Weyl semimetals.


title: Binary shuffle bases for quasi-symmetric functions

abstract:
  We construct bases of quasi-symmetric functions whose product rule is given
by the shuffle of binary words, as for multiple zeta values in their integral
representations, and then extend the construction to the algebra of free
quasi-symmetric functions colored by positive integers. As a consequence, we
show that the fractions introduced in [Guo and Xie, Ramanujan Jour. 25 (2011)
307-317] provide a realization of this algebra by rational moulds extending
that of free quasi-symmetric functions given in [Chapoton et al., Int. Math.
Res. Not. IMRN 2008, no. 9, Art. ID rnn018].


title:
Momentum diffusion of atoms and nanoparticles in an optical trap formed
  by sequences of counter-propagating light pulses

abstract:
  The motion of atoms and nanoparticles in a trap formed by sequences of
counter-propagating light pulses has been analyzed. The atomic state is
described by a wave function constructed with the use of the Monte Carlo
method, whereas the atomic motion is considered in the framework of classical
mechanics. The effects of the momentum diffusion associated with the
spontaneous radiation emission by excited atoms and the pulsed character of the
atom-to-field interaction on the motion of a trapped atom or nanoparticle are
estimated. The motion of a trapped atom is shown to be slowed down for properly
chosen parameters of the atom-to-field interaction, so that the atom oscillates
around the antinodes of a non-stationary standing wave formed by
counter-propagating light pulses at the point where they "collide".


title:
Odd parity pairing and nodeless anti-phase $s^\pm$ in Iron-Based
  Superconductors

abstract:
  We discuss the sign change of superconducting order parameters in both real
and reciprocal spaces when the odd parity spin singlet pairing proposed
recently in\cite{huoddparity} is allowed. We show that in this case an nodeless
anti-phase $s^\pm$ can be generated. In a 2-Fe Brilliouin zone (BZ), sign
change exists between two hole pockets and between two electron pockets. In a
1-Fe BZ which includes two 2-Fe BZs, the sign change is between two 2-Fe BZs,
which leads to a d-wave type sign distribution on the electron pockets, namely,
an anti-phase $s^\pm$ state with no symmetry protected gapless node on the
electron pockets. This sign change character consistently explains experimental
results related to sign change properties measured on both iron-pnictides and
iron-chalcogenides.


title:
A Study of starless dark cloud LDN 1570: Distance, Dust properties and
  Magnetic field geometry

abstract:
  We wish to map the magnetic field geometry and to study the dust properties
of the starless cloud, L1570, using multi-wavelength optical polarimetry and
photometry of the stars projected on the cloud. We made R-band imaging
polarimetry of the stars projected on a cloud, L1570, to trace the magnetic
field orientation. We also made multi-wavelength polarimetric and photometric
observations to constrain the properties of dust in L1570. We estimated a
distance of 394 +/- 70 pc to the cloud using 2MASS JHKs colours. Using the
values of the Serkowski parameters namely $\sigma_{1}$, $\bar \epsilon$,
{\lambda}max and the position of the stars on near infrared color-color
diagram, we identified 13 stars that could possibly have intrinsic polarization
and/or rotation in their polarization angles. One star, 2MASS
J06075075+1934177, which is a B4Ve spectral type, show the presence of diffuse
interstellar bands in the spectrum apart from showing H{\alpha} line in
emission. There is an indication for the presence of slightly bigger dust
grains towards L1570 on the basis of the dust grain size-indicators such as
{\lambda}max and Rv values. The magnetic field lines are found to be parallel
to the cloud structures seen in the 250{\mu}m images (also in 8{\mu}m and
12{\mu}m shadow images) of L1570. Based on the magnetic field geometry, the
cloud structure and the complex velocity structure, we believe that L1570 is in
the process of formation due to the converging flow material mediated by the
magnetic field lines. Structure function analysis showed that in the L1570
cloud region the large scale magnetic fields are stronger when compared with
the turbulent component of magnetic fields. The estimated magnetic field
strengths suggest that the L1570 cloud region is sub-critical and hence could
be strongly supported by the magnetic field lines.


title: Travelling wave analysis of a mathematical model of glioblastoma growth

abstract:
  In this paper we analyse a previously proposed cell-based model of
glioblastoma (brain tumour) growth, which is based on the assumption that the
cancer cells switch phenotypes between a proliferative and motile state (Gerlee
and Nelander, PLoS Comp. Bio., 8(6) 2012). The dynamics of this model can be
described by a system of partial differential equations, which exhibits
travelling wave solutions whose wave speed depends crucially on the rates of
phenotypic switching. We show that under certain conditions on the model
parameters, a closed form expression of the wave speed can be obtained, and
using singular perturbation methods we also derive an approximate expression of
the wave front shape. These new analytical results agree with simulations of
the cell-based model, and importantly show that the inverse relationship
between wave front steepness and speed observed for the Fisher equation no
longer holds when phenotypic switching is considered.


title:
Gravitational lensing shear by an exotic lens object with negative
  convergence or negative mass

abstract:
  Gravitational lens models with negative convergence(surface mass density
projected onto the lens plane) inspired by modified gravity theories, exotic
matter and energy have been recently discussed in such a way that a static and
spherically-symmetric modified spacetime metric depends on the inverse distance
to the power of positive $n$(n=1 for Schwarzschild metric, n=2 for Ellis
wormhole) in the weak-field approximation [Kitamura, Nakajima and Asada, PRD
87, 027501 (2013)], and it has been shown that demagnification of images could
occur for $n>1$ lens models associated with exotic matter (and energy), though
they cause the gravitational pull on light rays. The present paper considers
gravitational lensing shear by the demagnifying lens models and other models
such as negative-mass compact objects causing the gravitational repulsion on
light rays like a concave lens. It is shown that images by the lens models for
the gravitational pull are tangentially elongated, whereas those by the
repulsive ones are radially distorted. This feature of lensed image shapes may
be used for searching(or constraining) localized exotic matter or energy with
gravitational lensing surveys. It is suggested also that an underdense region
such as a cosmic void might produce radially elongated images of background
galaxies rather than tangential ones.


title:
Coherence revival during the attosecond electronic and nuclear quantum
  photodynamics of the ozone molecule

abstract:
  A coherent superposition of two electronic states of ozone (ground and
Hartley B) is prepared with a UV pump pulse. Using the multiconfiguration
time-dependent Hartree approach, we calculate the subsequent time evolution of
the two corresponding nuclear wave packets and the coherence between them. The
resulting wave packet shows an oscillation between the two chemical bonds. Even
more interesting, the coherence between the two electronics states reappears
after the laser pulse is switched off, which could be observed experimentally
with an attosecond probe pulse.


title:
Quasienergies and dynamics of superconducting qubit in time-modulated
  field

abstract:
  We analyze the dynamics of a superconducting qubit and the phenomenon of
multiorder Rabi oscillations in the presence of a time-modulated external
field. Such a field is also presented as a bichromatic field consisting of two
spectral components, which are symmetrically detuned from the qubit resonance
frequency. This approach leads to obtaining qualitative quantum effects beyond
those for the case of monochromatic excitation of qubits. We calculate Floquet
states and quasienergies of the composite system "superconducting qubit plus
time-modulated field" for various resonant regimes. We analyze the dependence
of quasienergies from the amplitude of an external field, demonstrating the
zeros of difference between quasienergies. We show that, as a rule, populations
of qubit states exhibit aperiodic oscillations, but we demonstrate the specific
important regimes in which dynamics of populations becomes periodically
regular.


title:
Some properties of generalized Fisher information in the context of
  nonextensive thermostatistics

abstract:
  We present two extended forms of Fisher information that fit well in the
context of nonextensive thermostatistics. We show that there exists an
interplay between these generalized Fisher information, the generalized
$q$-Gaussian distributions and the $q$-entropies. The minimum of the
generalized Fisher information among distributions with a fixed moment, or with
a fixed $q$-entropy is attained, in both cases, by a generalized $q$-Gaussian
distribution. This complements the fact that the $q$-Gaussians maximize the
$q$-entropies subject to a moment constraint, and yields new variational
characterizations of the generalized $q$-Gaussians. We show that the
generalized Fisher information naturally pop up in the expression of the time
derivative of the $q$-entropies, for distributions satisfying a certain
nonlinear heat equation. This result includes as a particular case the
classical de Bruijn identity. Then we study further properties of the
generalized Fisher information and of their minimization. We show that, though
non additive, the generalized Fisher information of a combined system is upper
bounded. In the case of mixing, we show that the generalized Fisher information
is convex for $q\geq1.$ Finally, we show that the minimization of the
generalized Fisher information subject to moment constraints satisfies a
Legendre structure analog to the Legendre structure of thermodynamics.

categories: math-ph cond-mat.stat-mech cs.IT math.IT math.MP


title: Longitudinal Schottky spectra of a bunched Ne10+ ion beam at the CSRe

abstract:
  The longitudinal Schottky spectra of a radio-frequency (RF) bunched and
electron cooled 22Ne10+ ion beam at 70 MeV/u have been studied by a newly
installed resonant Schottky pick-up at the experimental cooler storage ring
(CSRe), at IMP. For an RF-bunched ion beam, a longitudinal momentum spread of
has been reached with less than 107 stored ions. The reduction of momentum
spread compared with coasting ion beam was observed from Schottky noise signal
of the bunched ion beam. In order to prepare the future laser cooling
experiment at the CSRe, the RF-bunching power was modulated at 25th, 50th and
75th harmonic of the revolution frequency, effective bunching amplitudes were
extracted from the Schottky spectrum analysis. Applications of Schottky noise
for measuring beam lifetime with ultra-low intensity of ion beams are
presented, and it is relevant to upcoming experiments on laser cooling of
relativistic heavy ion beams and nuclear physics at the CSRe.


title: On the process dependent nuclear $k_\perp$ broadening effect

abstract:
  We study the process dependent nuclear $k_\perp$ broadening effect by
employing the transverse momentum dependent(TMD) factorization approach in
combination with the Mclerran-Venugopalan(MV) model. More specifically, we
investigate how the parton transverse momentum distributions are affected by
the process dependent gauge links in cold nuclear matter. In particular, our
analysis also applies to the polarized cases including the nuclear quark
Boer-Mulders function and the linearly polarized gluon distribution. Our main
focus is on the nuclear TMDs at intermediate or large x.


title: Dirac operators and the Very Strange Formula for Lie superalgebras

abstract:
  Using a super-affine version of Kostant's cubic Dirac operator, we prove a
very strange formula for quadratic finite-dimensional Lie superalgebras with a
reductive even subalgebra.


title: Uniform Treatment of Darboux's Method and the Heisenberg Polynomials

abstract:
  We show that the set of Heisenberg polynomials furnishes a simple non-trivial
example in the uniform treatment of Darboux's method.


title: A new two-component system modelling shallow-water waves

abstract:
  For propagation of surface shallow-water waves on irrotational flows, we
derive a new two-component system. The system is obtained by a variational
approach in the Lagrangian formalism. The system has a non-canonical
Hamiltonian formulation. We also find its exact solitary-wave solutions.


title:
A Nonlinear Pairwise Swapping Dynamics to Model the Selfish Rerouting
  Evolutionary Game

abstract:
  In this paper, a nonlinear revision protocol is proposed and embedded into
the traffic evolution equation of the classical proportional-switch adjustment
process (PAP), developing the present nonlinear pairwise swapping dynamics
(NPSD) to describe the selfish rerouting evolutionary game. It is demonstrated
that i) NPSD and PAP require the same amount of network information acquisition
in the route-swaps, ii) NPSD is able to prevent the over-swapping deficiency
under a plausible behavior description; iii) NPSD can maintain the solution
invariance, which makes the trial and error process to identify a feasible
step-length in a NPSD-based swapping algorithm is unnecessary, and iv) NPSD is
a rational behavior swapping process and the continuous-time NPSD is globally
convergent. Using the day-to-day NPSD, a numerical example is conducted to
explore the effects of the reaction sensitivity on traffic evolution and
characterize the convergence of discrete-time NPSD.


title: Variable Winds and Dust Formation in R Coronae Borealis Stars

abstract:
  We have observed P-Cygni and asymmetric, blue-shifted absorption profiles in
the He I 10830 lines of twelve R Coronae Borealis (RCB) stars over short (1
month) and long (3 year) timescales to look for variations linked to their
dust-formation episodes. In almost all cases, the strengths and terminal
velocities of the line vary significantly and are correlated with dust
formation events. Strong absorption features with blue-shifted velocities ~400
km/s appear during declines in visible brightness and persist for about 100
days after recovery to maximum brightness. Small residual winds of somewhat
lower velocity are present outside of the decline and recovery periods. The
correlations support models in which recently formed dust near the star is
propelled outward at high speed by radiation pressure and drags the gas along
with it.


title:
SGR 0418+5729, Swift J1822.3-1606, and 1E 2259+586 as massive fast
  rotating highly magnetized white dwarfs

abstract:
  Following Malheiro et al. (2012) we describe the so-called low magnetic field
magnetars, SGR 0418+5729, Swift J1822.3--1606, as well as the AXP prototype 1E
2259+586 as massive fast rotating highly magnetized white dwarfs. We give
bounds for the mass, radius, moment of inertia, and magnetic field for these
sources by requesting the stability of realistic general relativistic uniformly
rotating configurations. Based on these parameters, we improve the theoretical
prediction of the lower limit of the spindown rate of SGR 0418+5729; for a
white dwarf close to its maximum stable we obtain the very stringent interval
for the spindown rate of 4.1E-16< dP/dt < 6E-15, where the upper value is the
known observational limit. A lower limit has been also set for Swift
J1822.3-1606 for which a fully observationally accepted spin-down rate is still
lacking. The white dwarf model provides for this source dP/dt> 2.13E-15, if the
star is close to its maximum stable mass. We also present the theoretical
expectation of the infrared, optical and ultraviolet emission of these objects
and show their consistency with the current available observational data. We
give in addition the frequencies at which absorption features could be present
in the spectrum of these sources as the result of the scattering of photons
with the quantized electrons by the surface magnetic field.


title: Equivalence of 3D Spinning String and Superstring

abstract:
  We perform a light-cone gauge quantization of the Ramond closed spinning
string in three spacetime dimensions (3D). The spectrum is Lorentz invariant
and identical to that of the 3D Green-Schwarz closed superstring with ${\cal
N}=2$ space-time supersymmetry, quantized in light-cone gauge.


title: Social Network Games with Obligatory Product Selection

abstract:
  Recently, Apt and Markakis introduced a model for product adoption in social
networks with multiple products, where the agents, influenced by their
neighbours, can adopt one out of several alternatives (products). To analyze
these networks we introduce social network games in which product adoption is
obligatory.
  We show that when the underlying graph is a simple cycle, there is a
polynomial time algorithm allowing us to determine whether the game has a Nash
equilibrium. In contrast, in the arbitrary case this problem is NP-complete. We
also show that the problem of determining whether the game is weakly acyclic is
co-NP hard.
  Using these games we analyze various types of paradoxes that can arise in the
considered networks. One of them corresponds to the well-known Braess paradox
in congestion games. In particular, we show that social networks exist with the
property that by adding an additional product to a specific node, the choices
of the nodes will unavoidably evolve in such a way that everybody is strictly
worse off.


title:
Quantum molecular dynamics simulations of the thermophysical properties
  of shocked liquid ammonia for pressures up to 1.3 TPa

abstract:
  We investigate via quantum molecular-dynamics simulations the thermophysical
properties of shocked liquid ammonia up to the pressure 1.3 TPa and temperature
120000 K. The principal Hugoniot is predicted from wide-range equation of
state, which agrees well with available experimental measurements up to 64 GPa.
Our systematic study of the structural properties demonstrates that liquid
ammonia undergoes a gradual phase transition along the Hugoniot. At about 4800
K, the system transforms into a metallic, complex mixture state consisting of
$\textnormal{N}\textnormal{H}_{3}$, $\textnormal{N}_{2}$, $\textnormal{H}_{2}$,
N, and H. Furthermore, we discuss the implications for the interiors of Uranus
and Neptune.


title:
Interface kinetics in phase field models: isothermal transformations in
  binary alloys and steps dynamics in molecular-beam-epitaxy

abstract:
  We present a unified description of interface kinetic effects in phase field
models for isothermal transformations in binary alloys and steps dynamics in
molecular-beam-epitaxy. The phase field equations of motion incorporate a
kinetic cross-coupling between the phase field and the concentration field.
This cross coupling generalizes the phenomenology of kinetic effects and was
omitted until recently in classical phase field models. We derive general
expressions (independent of the details of the phase field model) for the
kinetic coefficients within the corresponding macroscopic approach using a
physically motivated reduction procedure. The latter is equivalent to the
so-called thin interface limit but is technically simpler. It involves the
calculation of the effective dissipation that can be ascribed to the interface
in the phase field model. We discuss in details the possibility of a non
positive definite matrix of kinetic coefficients, i.e. a negative effective
interface dissipation, although being in the range of stability of the
underlying phase field model. Numerically, we study the step-bunching
instability in molecular-beam-epitaxy due to the Ehrlich-Schwoebel effect,
present in our model due to the cross-coupling. Using the reduction procedure
we compare the results of the phase field simulations with the analytical
predictions of the macroscopic approach.


title:
Asymptotic Collusion-Proofness of Voting Rules: The Case of Large Number
  of Candidates

abstract:
  Classical results in voting theory show that strategic manipulation by voters
is inevitable if a voting rule simultaneously satisfy certain desirable
properties. Motivated by this, we study the relevant question of how often a
voting rule is manipulable. It is well known that elections with a large number
of voters are rarely manipulable under impartial culture (IC) assumption.
However, the manipulability of voting rules when the number of candidates is
large has hardly been addressed in the literature and our paper focuses on this
problem. First, we propose two properties (1) asymptotic strategy-proofness and
(2) asymptotic collusion-proofness, with respect to new voters, which makes the
two notions more relevant from the perspective of computational problem of
manipulation. In addition to IC, we explore a new culture of society where all
score vectors of the candidates are equally likely. This new notion has its
motivation in computational social choice and we call it impartial scores
culture (ISC) assumption. We study asymptotic strategy-proofness and asymptotic
collusion-proofness for plurality, veto, $k$-approval, and Borda voting rules
under IC as well as ISC assumptions. Specifically, we prove bounds for the
fraction of manipulable profiles when the number of candidates is large. Our
results show that the size of the coalition and the tie-breaking rule play a
crucial role in determining whether or not a voting rule satisfies the above
two properties.


title:
A phase field model for the optimization of the Willmore energy in the
  class of connected surfaces

abstract:
  We consider the problem of minimizing the Willmore energy connected surfaces
with prescribed surface area which are confined to a finite container. To this
end, we approximate the surface by a phase field function $u$ taking values
close to +1 on the inside of the surface and -1 on its outside. The confinement
of the surface is now simply given by the domain of definition of $u$. A
diffuse interface approximation for the area functional, as well as for the
Willmore energy are well known. We address the topological constraint of
connectedness by a nested minimization of two phase fields, the second one
being used to identify connected components of the surface. In this article, we
provide a proof of Gamma-convergence of our model to the sharp interface limit.


title: High-level Counterexamples for Probabilistic Automata

abstract:
  Providing compact and understandable counterexamples for violated system
properties is an essential task in model checking. Existing works on
counterexamples for probabilistic systems so far computed either a large set of
system runs or a subset of the system's states, both of which are of limited
use in manual debugging. Many probabilistic systems are described in a guarded
command language like the one used by the popular model checker PRISM. In this
paper we describe how a smallest possible subset of the commands can be
identified which together make the system erroneous. We additionally show how
the selected commands can be further simplified to obtain a well-understandable
counterexample.


title:
Comparison of Electromagnetically Induced Transparency in lambda,
  cascade and vee three-level systems

abstract:
  We discuss the Electromagnetically Induced Transparency (EIT) in lambda,
cascade and vee type three-level systems where the Hamiltonian and the Lindblad
term of each configuration are expressed in the $SU(3)$ representation. At
steady state, the Optical Bloch Equations of each configuration are solved to
obtain the dispersion and absorption profiles of the probe field along with
their group velocities. When the EIT condition is achieved at resonance, the
population oscillation shows which of the bare states are contributing to form
the dark state. Our study reveals that the dark state for the lambda and
cascade system effectively coincides with the lowest bare state of that system,
while for the vee system, it is a maximally superposed state of the middle and
upper bare states.


title: On lower bounds for cohomology growth in p-adic analytic towers

abstract:
  Let p and l be two distinct prime numbers and let G be a group. We study the
asymptotic behaviour of the mod-l Betti numbers in p-adic analytic towers of
finite index subgroups. If X is a finite l-group of automorphisms of G, our
main theorem allows to lift lower bounds for the mod-l cohomology growth in the
fixed point group G^X to lower bounds for the growth in G. We give applications
to S-arithmetic groups and we also obtain a similar result for cohomology with
rational coefficients.


title:
Quark-gluon mixed condensate for the SU(2) light-flavor sector at finite
  temperature

abstract:
  We investigate the quark-gluon mixed condensate <qbar sigma*G q> m^2_0 =
<qbar q> for the SU(2) light-flavor sector at finite temperature (T). Relevant
model parameters, such as the average (anti)instanton size,
inter-(anti)instanton distance, and constituent-quark mass at zero virtuality,
are modified as functions of T, employing the trivial-holonomy caloron
solution. By doing that, we observe correct chiral restoration patterns
depending on the current-quark mass m. We also perform the two-loop
renormalization-group (RG) evolution for the both condensates by increasing the
renormalization scale mu=(0.6~2.0) GeV. It turns out that the mixed condensate
is insensitive to the RG evolution, whereas the quark condensate become larger
considerably by the evolution. Numerically, we obtain -<qbar sigma*G q>^1/5 =
(0.45 ~ 0.46) GeV at T=0 within the present theoretical framework, and the
mixed condensate plays the role of the chiral order parameter for finite T. The
ratio of the two condensates m^2_0 is almost flat below the chiral transition T
(T_0), and increases rapidly beyond it. From a simple linear parametrization,
we obtain m^2_0(T)/m^2_0(0) ~ (0.07, 0.47) T/T_0 + (1,0.6) for (T<T_0, T>T_0)
at mu=0.6 GeV. The present results are compared with other theoretical ones
including the lattice QCD simulations, and show qualitatively good agreement
with them.


title: Search for the rare decay $D^0 \to \mu^+ \mu^-$

abstract:
  A search for the rare decay $D^0 \to \mu^+ \mu^-$is performed using a data
sample, corresponding to an integrated luminosity of 0.9 fb$^{-1}$, of $pp$
collisions collected at a centre-of-mass energy of 7 TeV by the LHCb
experiment. The observed number of events is consistent with the background
expectations and corresponds to an upper limit of \mbox{${\cal B}(D^0 \to \mu^+
\mu^-) < 6.2(7.6) \times 10^{-9}$} at \mbox{90%} \mbox{(95%)} confidence level.
This result represents an improvement of more than a factor twenty with respect
to previous measurements.


title: Conformally quasi-recurrent pseudo-Riemannian manifolds

abstract:
  Conformally quasi-recurrent (CQR)_n pseudo-Riemannian manifolds are
investigated, and several new results are obtained. It is shown that the Ricci
tensor and the gradient of the fundamental vector are Weyl compatible tensors
(the notion was introduced recently by the authors and applies to significative
space-times), (CQR)_n manifolds with concircular fundamental vector are
quasi-Einstein. For 4-dimensional (CQR)$_4$ Lorentzian manifolds the
fundamental vector is null and unique up to a scaling, it is an eigenvector of
the Ricci tensor, and its integral curves are geodesics. Such space-times are
Petrov type-N with respect to the fundamental null vector.


title:
Superconductor-normal metal quantum phase transition in dissipative and
  non-equilibrium systems

abstract:
  In physical systems, coupling to the environment gives rise to dissipation
and decoherence. For nanoscopic materials this may be a determining factor of
their physical behavior. However, even for macroscopic many-body systems, if
the strength of this coupling is sufficiently strong, their ground state
properties and phase diagram may be severely modified. Also dissipation is
essential to allow a system in the presence of a time dependent perturbation to
attain a steady, time independent state. In this case, the non-equilibrium
phase diagram depends on the intensity of the perturbation and on the strength
of the coupling of the system to the outside world. In this paper, we
investigate the effects of both, dissipation and time dependent external
sources in the phase diagram of a many-body system at zero and finite
temperatures. For concreteness we consider the specific case of a
superconducting layer under the action of an electric field and coupled to a
metallic substrate. The former arises from a time dependent vector potential
minimally coupled to the electrons in the layer. We introduce a Keldysh
approach that allows to obtain the time dependence of the superconducting order
parameter in an adiabatic regime. We study the phase diagram of this system as
a function of the electric field, the coupling to the metallic substrate and
temperature.


title: Dual redshift on Planck-scale-curved momentum spaces

abstract:
  Several approaches to the investigation of the quantum-gravity problem have
provided "theoretical evidence" of a role for the Planck scale in
characterizing the geometry of momentum space. One of the main obstructions for
a full exploitation of this scenario is the understanding of the role of the
Planck-scale-curved geometry of momentum space in the correlations between
emission and detection times, the "travel times" for a particle to go from a
given emitter to a given detector. These travel times appear to receive
Planck-scale corrections for which no standard interpretation is applicable,
and the associated implications for spacetime locality gave rise to the notion
of "relative locality" which is still in the early stages of investigation. We
here show that these Planck-scale corrections to travel times can be described
as "dual redshift" (or "lateshift"): they are manifestations of momentum-space
curvature of the same type already known for ordinary redshift produced by
spacetime curvature. In turn we can identify the novel notion of "relative
momentum-space locality" as a known but under-appreciated feature associated to
ordinary redshift produced by spacetime curvature, and this can be described in
complete analogy with the relative spacetime locality that became of interest
in the recent quantum-gravity literature. We also briefly comment on how these
findings may be relevant for an approach to the quantum-gravity problem
proposed by Max Born in 1938 and centered on Born duality.


title: The Polyharmonic Dirichlet Problem and Path Counting

abstract:
  The purpose of this article is to provide a solution to the $m$-fold Laplace
equation in the half space $R_+^d$ under certain Dirichlet conditions. The
solutions we present are a series of $m$ boundary layer potentials. We give
explicit formulas for these layer potentials as linear combinations of powers
of the Laplacian applied to the Dirichlet data, with coefficients determined by
certain path counting problems.


title:
Experimental and numerical characterisation of the turbulence in the
  Scrape-Off Layer of MAST

abstract:
  Numerical simulations of interchange turbulence in the Scrape-Off Layer are
performed in a regime relevant for a specific L-mode MAST (Mega Ampere
Spherical Tokamak) discharge. Such a discharge was diagnosed with a
reciprocating arm equipped with a Gundestrup probe. A detailed comparison of
the average and statistical properties of the simulated and experimental ion
saturation current is performed. Good agreement is found in the time averaged
radial profile, in the probability distribution functions (PDFs) and in
qualitative features of the signals such as the shape, duration and separation
of burst events. These results confirm the validity of the simple interchange
model used and help to identify where it can be improved. Finally, the
simulated data are used to assess the importance of the temperature
fluctuations on plasma potential and radial velocity measurements acquired with
Langmuir probes. It is shown that the correlation between the actual plasma
quantities and the signal of the synthetic diagnostics is poor, suggesting that
accurate measurements of the temperature fluctuations are needed in order to
obtain reliable estimates of the perpendicular fluxes.


title: High Energy Emission Processes in OJ 287 during 2009 Flare

abstract:
  The broadband spectrum of a BL Lac object, OJ 287, from radio to
$\gamma$-rays obtained during a major $\gamma$-ray flare detected by
\emph{Fermi} in 2009 are studied to understand the high energy emission
mechanism during this episode. Using a simple one-zone leptonic model,
incorporating synchrotron and inverse Compton emission processes, we show that
the explanation of high energy emission from X-rays to $\gamma$-rays, by
considering a single emission mechanism, namely, synchrotron self-Compton (SSC)
or external Compton (EC) requires unlikely physical conditions. However, a
combination of both SSC and EC mechanisms can reproduce the observed high
energy spectrum satisfactorily. Using these emission mechanisms we extract the
physical parameters governing the source and its environment. Our study
suggests that the emission region of OJ 287 is surrounded by a warm infrared
(IR) emitting region of $\sim 250 \, K$. Assuming this region as a spherical
cloud illuminated by an accretion disk, we obtain the location of the emission
region to be $\sim 9 pc$. This supports the claim that the $\gamma$-ray
emission from OJ 287 during the 2009 flare arises from a location far away from
the central engine as deduced from millimeter-gamma ray correlation study and
very long baseline array images.


title: Comparison of some Reduced Representation Approximations

abstract:
  In the field of numerical approximation, specialists considering highly
complex problems have recently proposed various ways to simplify their
underlying problems. In this field, depending on the problem they were tackling
and the community that are at work, different approaches have been developed
with some success and have even gained some maturity, the applications can now
be applied to information analysis or for numerical simulation of PDE's. At
this point, a crossed analysis and effort for understanding the similarities
and the differences between these approaches that found their starting points
in different backgrounds is of interest. It is the purpose of this paper to
contribute to this effort by comparing some constructive reduced
representations of complex functions. We present here in full details the
Adaptive Cross Approximation (ACA) and the Empirical Interpolation Method (EIM)
together with other approaches that enter in the same category.


title: Parametric Stein operators and variance bounds

abstract:
  Stein operators are differential operators which arise within the so-called
Stein's method for stochastic approximation. We propose a new mechanism for
constructing such operators for arbitrary (continuous or discrete) parametric
distributions with continuous dependence on the parameter. We provide explicit
general expressions for location, scale and skewness families. We also provide
a general expression for discrete distributions. For specific choices of target
distributions (including the Gaussian, Gamma and Poisson) we compare the
operators hereby obtained with those provided by the classical approaches from
the literature on Stein's method. We use properties of our operators to provide
upper and lower variance bounds (only lower bounds in the discrete case) on
functionals $h(X)$ of random variables $X$ following parametric distributions.
These bounds are expressed in terms of the first two moments of the derivatives
(or differences) of $h$. We provide general variance bounds for location, scale
and skewness families and apply our bounds to specific examples (namely the
Gaussian, exponential, Gamma and Poisson distributions). The results obtained
via our techniques are systematically competitive with, and sometimes improve
on, the best bounds available in the literature.


title:
Protein folding: Complex potential for the driving force in a
  two-dimensional space of collective variables

abstract:
  Using the Helmholtz decomposition of the vector field of folding fluxes in a
two-dimensional space of collective variables, a potential of the driving force
for protein folding is introduced. The potential has two components. One
component is responsible for the source and sink of the folding flows, which
represent, respectively, the unfolded states and the native state of the
protein, and the other, which accounts for the flow vorticity inherently
generated at the periphery of the flow field, is responsible for the
canalization of the flow between the source and sink. The theoretical
consideration is illustrated by calculations for a model $\beta$-hairpin
protein.


title:
Realization of a double barrier resonant tunneling diode for cavity
  polaritons

abstract:
  We report on the realization of a double barrier resonant tunneling diode for
cavity polaritons, by lateral patterning of a one-dimensional cavity. Sharp
transmission resonances are demonstrated when sending a polariton flow onto the
device. We use a non-resonant beam can be used as an optical gate and control
the device transmission. Finally we evidence distortion of the transmission
profile when going to the high density regime, signature of polariton-polariton
interactions.