title: Perpetual motion of a mobile impurity in a one-dimensional quantum gas

abstract:
  Consider an impurity particle injected in a degenerate one-dimensional gas of
noninteracting fermions (or, equivalently, Tonks-Girardeau bosons) with some
initial momentum $p_0$. We examine the infinite-time value of the momentum of
the impurity, $p_\infty$, as a function of $p_0$. A lower bound on
$|p_\infty(p_0)|$ is derived under fairly general conditions. The derivation,
based on the existence of the lower edge of the spectrum of the host gas, does
not resort to any approximations. The existence of such bound implies the
perpetual motion of an impurity in a one-dimensional gas of noninteracting
fermions or Tonks-Girardeau bosons at zero temperature. The bound has an
especially simple and useful form when the interaction between the impurity and
host particles is everywhere repulsive.

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


title:
Extraordinary optical transmission and vortex excitation by periodic
  arrays of Fresnel zone plates

abstract:
  Extraordinary optical transmission and good focusing properties of a
two-dimensional scattering structure is presented. The structure is made of
Fresnel zone plates periodically arranged along two orthogonal directions. Each
plate consists of two ring-shaped waveguides supporting modes that match the
symmetry of a circularly polarized incident plane wave. High field
concentration at the focal plane is obtained with short transverse and long
longitudinal foci diameters. Optical vortex excitation in a paraxial region of
the transmitted field is also observed and analysed in terms of
cross-polarisation coupling. The structure presented may appear useful in
visualization, trapping and precise manipulations of nanoparticles.


title:
The Thermal Discrete Dipole Approximation (T-DDA) for near-field
  radiative heat transfer simulations in three-dimensional arbitrary geometries

abstract:
  A novel numerical method called the Thermal Discrete Dipole Approximation
(T-DDA) is proposed for modeling near-field radiative heat transfer in
three-dimensional arbitrary geometries. The T-DDA is conceptually similar to
the Discrete Dipole Approximation, except that the incident field originates
from thermal oscillations of dipoles. The T-DDA is described in details in the
paper, and the method is tested against exact results of radiative conductance
between two spheres separated by a sub-wavelength vacuum gap. For all cases
considered, the results calculated from the T-DDA are in good agreement with
those from the analytical solution. When considering frequency-independent
dielectric functions, it is observed that the number of sub-volumes required
for convergence increases as the sphere permittivity increases. Additionally,
simulations performed for two silica spheres of 0.5 micrometer-diameter show
that the resonant modes are predicted accurately via the T-DDA. For separation
gaps of 0.5 micrometer and 0.2 micrometer, the relative differences between the
T-DDA and the exact results are 0.35% and 6.4%, respectively, when 552
sub-volumes are used to discretize a sphere. Finally, simulations are performed
for two cubes of silica separated by a sub-wavelength gap. The results revealed
that faster convergence is obtained when considering cubical objects rather
than curved geometries. This work suggests that the T-DDA is a robust numerical
approach that can be employed for solving a wide variety of near-field thermal
radiation problems in three-dimensional geometries.


title: Asymptotic quantum many-body localization from thermal disorder

abstract:
  We consider a quantum lattice system with infinite-dimensional on-site
Hilbert space, very similar to the Bose-Hubbard model. We investigate many-body
localization in this model, induced by thermal fluctuations rather than
disorder in the Hamiltonian. We provide evidence that the Green-Kubo
conductivity $\kappa(\beta)$, defined as the time-integrated current
autocorrelation function, decays faster than any polynomial in the inverse
temperature $\beta$ as $\beta \to 0$. More precisely, we define approximations
$\kappa_{\tau}(\beta)$ to $\kappa(\beta)$ by integrating the current-current
autocorrelation function up to a large but finite time $\tau$ and we rigorously
show that $\beta^{-n}\kappa_{\beta^{-m}}(\beta)$ vanishes as $\beta \to 0$, for
any $n,m \in \mathbb{N}$ such that $m-n$ is sufficiently large.


title: Moments Method for Shell-Model Level Density

abstract:
  The modern form of the Moments Method applied to the calculation of the
nuclear shell-model level density is explained and examples of the method at
work are given. The calculated level density practically exactly coincides with
the result of full diagonalization when the latter is feasible. The method
provides the pure level density for given spin and parity with spurious
center-of-mass excitations subtracted. The presence and interplay of all
correlations leads to the results different from those obtained by the
mean-field combinatorics.


title: Linear Sigma Models With Strongly Coupled Phases -- One Parameter Models

abstract:
  We systematically construct a class of two-dimensional $(2,2)$ supersymmetric
gauged linear sigma models with phases in which a continuous subgroup of the
gauge group is totally unbroken. We study some of their properties by employing
a recently developed technique. The focus of the present work is on models with
one K\"ahler parameter. The models include those corresponding to Calabi-Yau
threefolds, extending three examples found earlier by a few more, as well as
Calabi-Yau manifolds of other dimensions and non-Calabi-Yau manifolds. The
construction leads to predictions of equivalences of D-brane categories,
systematically extending earlier examples. There is another type of surprise.
Two distinct superconformal field theories corresponding to Calabi-Yau
threefolds with different Hodge numbers, $h^{2,1}=23$ versus $h^{2,1}=59$, have
exactly the same quantum K\"ahler moduli space. The strong-weak duality plays a
crucial r\^ole in confirming this, and also is useful in the actual computation
of the metric on the moduli space.


title: Comment on "Anomaly Mediation from Unbroken Supergravity"

abstract:
  I argue that ArXiv:1307.3251 is based on a misunderstanding of the role of
Weyl transformations in local off-shell supersymmetry and what constitutes a
true symmetry of the theory.


title:
The weakly nonlinear large box limit of the 2D cubic nonlinear
  Schr\"odinger equation

abstract:
  We consider the cubic nonlinear Schr\"odinger (NLS) equation set on a two
dimensional box of size $L$ with periodic boundary conditions. By taking the
large box limit $L \to \infty$ in the weakly nonlinear regime (characterized by
smallness in the critical space), we derive a new equation set on $\R^2$ that
approximates the dynamics of the frequency modes. This nonlinear equation turns
out to be Hamiltonian and enjoys interesting symmetries, such as its invariance
under Fourier transform, as well as several families of explicit solutions. A
large part of this work is devoted to a rigorous approximation result that
allows to project the long-time dynamics of the limit equation into that of the
cubic NLS equation on a box of finite size.


title: Complementarity + Back-reaction is enough

abstract:
  We investigate a recent development of the black hole information problem, in
which a practical paradox has been formulated to show that complementarity is
insufficient. A crucial ingredient in this practical paradox is to distill
information from the early Hawking radiation within the past lightcone of the
black hole. By causality this action can back-react on the black hole. Taking
this back-reaction into account, the paradox could be resolved without invoking
any new physics beyond complementarity. This resolution requires a certain
constraint on the S-matrix to be satisfied. Further insights into the S-matrix
could potentially be obtained by effective-field-theory computations of the
back-reaction on the nice slice.


title: Tunneling at $\nu_T=1$ in Quantum Hall Bilayers

abstract:
  Interlayer tunneling measurements in the strongly correlated bilayer
quantized Hall phase at $\nu_T=1$ are reported. The maximum, or critical
current for tunneling at $\nu_T=1$, is shown to be a well-defined global
property of the coherent phase, insensitive to extrinsic circuit effects and
the precise configuration used to measure it, but also exhibiting a surprising
scaling behavior with temperature. Comparisons between the experimentally
observed tunneling characteristics and a recent theory are favorable at high
temperatures, but not at low temperatures where the tunneling closely resembles
the dc Josephson effect. The zero-bias tunneling resistance becomes extremely
small at low temperatures, vastly less than that observed at zero magnetic
field, but nonetheless remains finite. The temperature dependence of this
tunneling resistance is similar to that of the ordinary in-plane resistivity of
the quantum Hall phase.


title: Simulation of rare events in quantum error correction

abstract:
  We consider the problem of calculating the logical error probability for a
stabilizer quantum code subject to random Pauli errors. To access the regime of
large code distances where logical errors are extremely unlikely we adopt the
splitting method widely used in Monte Carlo simulations of rare events and
Bennett's acceptance ratio method for estimating the free energy difference
between two canonical ensembles. To illustrate the power of these methods in
the context of error correction, we calculate the logical error probability
$P_L$ for the 2D surface code on a square lattice with a pair of holes for all
code distances $d\le 20$ and all error rates $p$ below the fault-tolerance
threshold. Our numerical results confirm the expected exponential decay
$P_L\sim \exp{[-\alpha(p)d]}$ and provide a simple fitting formula for the
decay rate $\alpha(p)$. Both noiseless and noisy syndrome readout circuits are
considered.


title:
Re-entrant magnetic field induced charge and spin gaps in the coupled
  dual-chain quasi-one dimensional organic conductor Perylene$_2$[Pt(mnt)$_2$]

abstract:
  An inductive method is used to follow the magnetic field-dependent
susceptibility of the coupled charge density wave (CDW) and spin-Peierls (SP)
ordered state behavior in the dual chain organic conductor
Perylene$_2$[Pt(mnt)$_2$]. In addition to the coexisting SP-CDW state phase
below 8 K and 20 T, the measurements show that a second spin-gapped phase
appears above 20 T that coincides with a field-induced insulating phase. The
results support a strong coupling of the CDW and SP order parameters even in
high magnetic fields, and provide new insight into the nature of the magnetic
susceptibility of dual-chain spin and charge systems.


title: Emission source functions in heavy ion collisions

abstract:
  The three-dimensional pion and kaon emission source functions are extracted
from the HKM model simulations of the central Au+Au collisions at the top RHIC
energy $\sqrt{s_{NN}}=200$ GeV. The model describes well the experimental data,
previously obtained by the PHENIX and STAR collaborations using the imaging
technique. In particular, the HKM reproduces the non-Gaussian heavy tails of
the source function in the pair transverse momentum (out) and beam (long)
directions, observed in the pion case and practically absent for kaons. The
role of the rescatterings and long-lived resonances decays in forming of the
mentioned long range tails is investigated. The particle rescatterings
contribution to the out tail seems to be dominating. The model calculations
also show the substantial relative emission times between pions (with mean
value 14.5 fm/c in LCMS), including those coming from resonance decays and
rescatterings. The prediction is made for the source functions in the LHC Pb+Pb
collisions at $\sqrt{s_{NN}}=2.76$ TeV, which are still not extracted from the
measured correlation functions.


title: New Algorithms for Learning Incoherent and Overcomplete Dictionaries

abstract:
  In sparse recovery we are given a matrix $A$ (the dictionary) and a vector of
the form $A X$ where $X$ is sparse, and the goal is to recover $X$. This is a
central notion in signal processing, statistics and machine learning. But in
applications such as sparse coding, edge detection, compression and super
resolution, the dictionary $A$ is unknown and has to be learned from random
examples of the form $Y = AX$ where $X$ is drawn from an appropriate
distribution --- this is the dictionary learning problem. In most settings, $A$
is overcomplete: it has more columns than rows. This paper presents a
polynomial-time algorithm for learning overcomplete dictionaries; the only
previously known algorithm with provable guarantees is the recent work of
Spielman, Wang and Wright who gave an algorithm for the full-rank case, which
is rarely the case in applications. Our algorithm applies to incoherent
dictionaries which have been a central object of study since they were
introduced in seminal work of Donoho and Huo. In particular, a dictionary is
$\mu$-incoherent if each pair of columns has inner product at most $\mu /
\sqrt{n}$.
  The algorithm makes natural stochastic assumptions about the unknown sparse
vector $X$, which can contain $k \leq c \min(\sqrt{n}/\mu \log n, m^{1/2
-\eta})$ non-zero entries (for any $\eta > 0$). This is close to the best $k$
allowable by the best sparse recovery algorithms even if one knows the
dictionary $A$ exactly. Moreover, both the running time and sample complexity
depend on $\log 1/\epsilon$, where $\epsilon$ is the target accuracy, and so
our algorithms converge very quickly to the true dictionary. Our algorithm can
also tolerate substantial amounts of noise provided it is incoherent with
respect to the dictionary (e.g., Gaussian). In the noisy setting, our running
time and sample complexity depend polynomially on $1/\epsilon$, and this is
necessary.


title:
Electrophoretic-like gating used to control metal-insulator transitions
  in electronically phase separated manganite wires

abstract:
  Electronically phase separated manganite wires are found to exhibit
controllable metal-insulator transitions under local electric fields. The
switching characteristics are shown to be fully reversible, polarity
independent, and highly resistant to thermal breakdown caused by repeated
cycling. It is further demonstrated that multiple discrete resistive states can
be accessed in a single wire. The results conform to a phenomenological model
in which the inherent nanoscale insulating and metallic domains are rearranged
through electrophoretic-like processes to open and close percolation channels.


title: Local transport measurements on epitaxial graphene

abstract:
  Growth of large-scale graphene is still accompanied by imperfections. By
means of a four-tip STM/SEM the local structure of graphene grown on SiC(0001)
was correlated with scanning electron microscope images and spatially resolved
transport measurements. The systematic variation of probe spacings and
substrate temperature has clearly revealed two-dimensional transport regimes of
Anderson localization as well as of diffusive transport. The detailed analysis
of the temperature dependent data demonstrates that the local on-top nano-sized
contacts do not induce significant strain to the epitaxial graphene films.


title: Fast community detection using local neighbourhood search

abstract:
  Communities play a crucial role to describe and analyse modern networks.
However, the size of those networks has grown tremendously with the increase of
computational power and data storage. While various methods have been developed
to extract community structures, their computational cost or the difficulty to
parallelize existing algorithms make partitioning real networks into
communities a challenging problem. In this paper, we propose to alter an
efficient algorithm, the Louvain method, such that communities are defined as
the connected components of a tree-like assignment graph. Within this
framework, we precisely describe the different steps of our algorithm and
demonstrate its highly parallelizable nature. We then show that despite its
simplicity, our algorithm has a partitioning quality similar to the original
method on benchmark graphs and even outperforms other algorithms. We also show
that, even on a single processor, our method is much faster and allows the
analysis of very large networks.


title: Gauge nonlocality in planar quantum-coherent systems

abstract:
  It is shown that a system with quantum coherence can be nontrivially affected
by adjacent magnetic or adjacent time-varying electric field regions, with this
proximity (or remote) influence having a gauge origin. This is implicit
(although overlooked) in numerous works on extended systems with inhomogeneous
magnetic fields (with either conventional or Dirac materials) but is generally
plagued with an apparent gauge ambiguity. The origin of this annoying feature
is explained and it is shown how it can be theoretically removed, leading to
macroscopic quantizations (quantized Dirac monopoles, integral quantum Hall
effect, quantized magnetoelectric phenomena in topological insulators). Apart
however from serving as a theoretical probe of macroscopic quantizations, there
are cases (experimental conditions, clarified here) when this "gauge
nonlocality" does not really suffer from any ambiguity: an apparently innocent
gauge transformation corresponds to real change in physics of a companion
system in higher dimensionality, that leads to physical momentum transfers to
our own system. This nonlocality, together with the associated "proximity" or
remote effects are then real and lead to the remarkable possibility of inducing
topological phenomena from outside our system (which always remains field-free
and can even reside in simply-connected space). Specific procedures are then
proposed to experimentally detect such types of nonlocal effects and exploit
them for novel applications. General consequences in solid state physics (such
as the first violation of Bloch theorem in a field-free quantum periodic
system) are pointed out, and formal analogies with certain high energy physics
phenomena (axions, {\theta}-vacua and some types of Gribov ambiguities), as
well as with certain largely unexplored phenomena in mechanics and in
thermodynamics, are noted.


title:
Probing the cosmic-ray content of galaxy clusters by stacking Fermi-LAT
  count maps

abstract:
  Observations in radio have shown that galaxy clusters are giant reservoirs of
cosmic rays (CR). Although a gamma- ray signal from the cluster volume is
expected to arise through interactions of CR protons with the ambient plasma, a
confirming observation is still missing. We search for a cumulative gamma-ray
emission in direction of galaxy clusters by analysing a collection of stacked
Fermi-LAT count maps. Additionally, we investigate possible systematic
differences in the emission between cool-core and non-cool core cluster
populations. Making use of a sample of 53 clusters selected from the HIFLUGCS
catalog, we do not detect a significant signal from the stacked sample. The
upper limit on the average flux per cluster derived for the total stacked
sample is at the level of a few 1e-11 ph cm-2 s-1 at 95% confidence level in
the 1-300 GeV band, assuming power-law spectra with photon indices 2.0, 2.4,
2.8 and 3.2. Separate stacking of the cool core and non-cool core clusters in
the sample lead to similar values of around 5e-11 ph cm-2 s-1 and 2e-11 ph cm-2
s-1, respectively. Under the assumption that decaying pi0, produced in
collisions between CRs and the ambient thermal gas, are responsible for the
gamma-ray emission, we set upper limits on the average CR content in galaxy
clusters. For the entire cluster population, our upper limit on the gamma-ray
flux translates into an upper limit on the average CR-to-thermal energy ratio
of 4.6% for a photon index of 2.4, although it is possible for individual
systems to exceed this limit. Our 95% upper limits are at the level expected
from numerical simulations, which likely suggests that the injection of CR at
cosmological shocks is less efficient than previously assumed.


title: On the frequency of planetary systems around G-dwarfs

abstract:
  We determine the fraction of G-dwarf stars that could host stable planetary
systems based on the observed properties of binaries in the Galactic field, and
in various postulated primordial binary populations, which assume that the
primordial binary fraction is higher than that in the field. We first consider
the frequency of Solar System analogues - planetary systems that form either
around a single G-dwarf star, or a binary containing a G-dwarf where the binary
separation exceeds 100-300au. If the primordial binary fraction and period
distribution is similar to that in the field, then up to 63 per cent of G-dwarf
systems could potentially host a Solar System analogue. However, if the
primordial binary fraction is higher, the fraction of G-dwarf systems that
could host a planetary system like our own is lowered to 38 per cent.
  We extend our analysis to consider the fraction of G-dwarf systems (both
single and binary) that can host either circumprimary planets (orbiting the
primary star of the binary) or circumbinary planets (orbiting both stars in the
binary) for fiducial planetary separations between 1 - 100au. Depending on the
assumed binary population, in the circumprimary case between 65 and 95 per cent
of systems can host a planet at 1au, decreasing to between 20 and 65 per cent
of systems that can host a planet at 100au. In the circumbinary case, between 5
and 59 per cent of systems can host a planet at 1au, increasing to between 34
and 75 per cent of systems that can host a planet at 100au.
  Our results suggest that the assumed binary fraction is the key parameter in
determining the fraction of potentially stable planetary systems in G-dwarf
systems and that using the present-day value may lead to significant
overestimates if the binary fraction was initially higher.


title:
CLASH: z ~ 6 young galaxy candidate quintuply lensed by the frontier
  field cluster RXC J2248.7-4431

abstract:
  We present a quintuply lensed z ~ 6 candidate discovered in the field of the
galaxy cluster RXC J2248.7-4431 (z ~ 0.348) targeted within the Cluster Lensing
and Supernova survey with Hubble (CLASH) and selected in the deep HST Frontier
Fields survey. Thanks to the CLASH 16-band HST imaging, we identify the
quintuply lensed z ~ 6 candidate as an optical dropout in the inner region of
the cluster, the brightest image having magAB=24.81+-0.02 in the f105w filter.
We perform a detailed photometric analysis to verify its high-z and lensed
nature. We get as photometric redshift z_phot ~ 5.9, and given the extended
nature and NIR colours of the lensed images, we rule out low-z early type and
galactic star contaminants. We perform a strong lensing analysis of the
cluster, using 13 families of multiple lensed images identified in the HST
images. Our final best model predicts the high-z quintuply lensed system with a
position accuracy of 0.8''. The magnifications of the five images are between
2.2 and 8.3, which leads to a delensed UV luminosity of L_1600 ~ 0.5L*_1600 at
z=6. We also estimate the UV slope from the observed NIR colours, finding a
steep beta=-2.89+-0.38. We use singular and composite stellar population SEDs
to fit the photometry of the hiz candidate, and we conclude that it is a young
(age <300 Myr) galaxy with mass of M ~ 10^8Msol, subsolar metallicity
(Z<0.2Zsol) and low dust content (AV ~ 0.2-0.4).


title: The discovery of a population of gamma-ray novae

abstract:
  Novae have long been expected to be sources of emission at several MeV from
the decay of radioactive elements in the novae ejecta, however, they were not
anticipated to be sources of continuum emission in the GeV energy domain. In
March 2010 the Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space
Telescope discovered for the first time >100 MeV gamma-ray emission from a nova
within our galaxy, V407 Cyg. The high-energy spectrum and light curve was
explained as a consequence of shock acceleration in the nova shell as it
interacts with the local ambient medium. While this was an exciting and
important discovery it was suspected that the necessary conditions for
high-energy emission from novae would be rare. In June 2012 the LAT detected
two new transient sources that have been associated with classical novae
observed in the optical, Nova Sco 2012 and Nova Mon 2012. We report on the
observational properties of the population of gamma-ray novae, their
similarities and differences and the emission processes that generate the high
energy radiation in these systems.


title:
A survey of volatile species in Oort cloud comets C/2001 Q4 (NEAT) and
  C/2002 T7 (LINEAR) at millimeter wavelengths

abstract:
  The line emission in the coma was measured in the comets C/2001 Q4 (NEAT) and
C/2002 T7 (LINEAR), that were observed on five consecutive nights, 7-11 May
2004, at heliocentric distances of 1.0 and 0.7 AU, respectively, by means of
high-resolution spectroscopy using the 10-m Submillimeter Telescope (SMT). We
present a search for six parent- and product-volatile species (HCN, H2CO, CO,
CS, CH3OH, and HNC) in both comets. Multiline observations of the CH3OH J = 5-4
series allow us to estimate the rotational temperature using the rotation
diagram technique. We derive rotational temperatures of 54(9) K for C/2001 Q4
(NEAT) and 119(34) K for C/2002 T7 (LINEAR) that are roughly consistent with
observations of other comets at similar distances from the Sun. The gas
production rates of material are computed using a spherically symmetric
molecular excitation code that includes collisions between neutrals and
electrons. We find an HCN production rate of 2.96(5)e26 molec.s-1 for comet
C/2001 Q4 (NEAT), corresponding to a mixing ratio with respect to H2O of
1.12(2)e-3. The mean HCN production rate during the observing period is
4.54(10)e26 molec.s-1 for comet C/2002 T7 (LINEAR), which gives a Q_HCN/Q_H2O
mixing ratio of 1.51(3)e-3. With systematically lower mixing ratios in comet
C/2001 Q4 (NEAT), production rate ratios of the observed species with respect
to H2O lie within the typical ranges of dynamically new comets in both objects.
We find a relative low abundance of CO in C/2001 Q4 (NEAT) compared to the
observed range in other comets based on millimeter/submillimeter observations,
and a significant upper limit on the CO production in C/2002 T7 (LINEAR) is
derived. Depletion of CO suggests partial evaporation from the surface layers
during previous visits to the outer Solar System and agrees with previous
measurements of dynamically new comets.


title: Electric Dipole Moments in Two-Higgs-Doublet Models

abstract:
  Electric dipole moments are extremely sensitive probes for additional sources
of CP violation in new physics models. Specifically, they have been argued in
the past to exclude new CP-violating phases in two-Higgs-doublet models. Since
recently models including such phases have been discussed widely, we revisit
the available constraints in the presence of mechanisms which are typically
invoked to evade flavour-changing neutral currents. To that aim, we start by
assessing the necessary calculations on the hadronic, nuclear and
atomic/molecular level, deriving expressions with conservative error estimates.
Their phenomenological analysis in the context of two-Higgs-doublet models
yields strong constraints, in some cases weakened by a cancellation mechanism
among contributions from neutral scalars. While the corresponding parameter
combinations do not yet have to be unnaturally small, the constraints are
likely to preclude large effects in other CP-violating observables.
Nevertheless, the generically expected contributions to electric dipole moments
in this class of models lie within the projected sensitivity of the
next-generation experiments.


title: The physics and cosmology of TeV blazars in a nutshell

abstract:
  The extragalactic gamma-ray sky at TeV energies is dominated by blazars, a
subclass of accreting super-massive black holes with powerful relativistic
outflows directed at us. Only constituting a small fraction of the total power
output of black holes, blazars were thought to have a minor impact on the
universe at best. As we argue here, the opposite is true and the gamma-ray
emission from TeV blazars can be thermalized via beam-plasma instabilities on
cosmological scales with order unity efficiency, resulting in a potentially
dramatic heating of the low-density intergalactic medium. Here, we review this
novel heating mechanism and explore the consequences for the formation of
structure in the universe. In particular, we show how it produces an inverted
temperature-density relation of the intergalactic medium that is in agreement
with observations of the Lyman-alpha forest. This suggests that blazar heating
can potentially explain the paucity of dwarf galaxies in galactic halos and
voids, and the bimodality of galaxy clusters. This also transforms our
understanding of the evolution of blazars, their contribution to the
extra-galactic gamma-ray background, and how their individual spectra can be
used in constraining intergalactic magnetic fields.


title: Construction of an asymptotic S matrix for perturbative quantum gravity

abstract:
  The infrared behavior of perturbative quantum gravity is studied using the
method developed for QED by Faddeev and Kulish. The operator describing the
asymptotic dynamics is derived and used to construct an IR-finite S matrix and
space of asymptotic states. All-orders cancellation of IR divergences is shown
explicitly at the level of matrix elements for the example case of
gravitational potential scattering. As a practical application of the
formalism, the soft part of a scalar scattering amplitude is related to the
gravitational Wilson line and computed to all orders.


title: Are group- and cluster-scale dark matter halos over-concentrated?

abstract:
  We investigate the relationship between the halo mass, M_200, and
concentration, c, for a sample of 26 group- and cluster-scale strong
gravitational lenses. In contrast with previous results, we find that these
systems are only ~ 0.1 dex more over-concentrated than similar-mass halos from
dark matter simulations; the concentration of a halo with M_200 = 10^14 M_sun
is log c = 0.78\pm0.05, while simulations of halos with this mass at similar
redshifts (z ~ 0.4) predict log c ~ 0.56 - 0.71. We also find that we are
unable to make informative inference on the slope of the M_200-c relation in
spite of our large sample size; we note that the steep slopes found in previous
studies tend to follow the slope in the covariance between M_200 and c,
indicating that these results may be measuring the scatter in the data rather
than the intrinsic signal. Furthermore, we conclude that our inability to
constrain the M_200-c slope is due to a limited range of halo masses, as
determined by explicitly modelling our halo mass distribution, and we suggest
that other studies may be producing biased results by using an incorrect
distribution for their halo masses.


title: Proximity effect in graphene-topological insulator heterostructures

abstract:
  We formulate a continuum model to study the low-energy electronic structure
of heterostructures formed by graphene on a strong three-dimensional
topological insulator (TI) for the case of both commensurate and incommensurate
stacking. The incommensurability can be due to a twist angle between graphene
and the TI surface or a lattice mismatch between the two systems. We find that
the proximity of the TI induces in graphene a strong enhancement of the
spin-orbit coupling that can be tuned via the twist angle.


title:
Model-independent WIMP Scattering Responses and Event Rates: A
  Mathematica Package for Experimental Analysis

abstract:
  The community's reliance on simplified descriptions of WIMP-nucleus
interactions reflects the absence of analysis tools that integrate general
theories of dark matter with standard treatments of nuclear response functions.
To bridge this gap, we have constructed a public-domain Mathematica package for
WIMP analyses based on our effective theory formulation. Script inputs are 1)
the coefficients of the effective theory, through which one can characterize
the low-energy consequences of arbitrary ultraviolet theories of WIMP
interactions; and 2) one-body density matrices for commonly used targets, the
most compact description of the relevant nuclear physics. The generality of the
effective theory expansion guarantees that the script will remain relevant as
new ultraviolet theories are explored; the use of density matrices to factor
the nuclear physics from the particle physics will allow nuclear structure
theorists to update the script as new calculations become available,
independent of specific particle-physics contexts. The Mathematica package
outputs the resulting response functions (and associated form factors) and also
the differential event rate, once a galactic WIMP velocity profile is
specified, and thus in its present form provides a complete framework for
experimental analysis. The Mathematica script requires no a priori knowledge of
the details of the non-relativistic effective field theory or nuclear physics,
though the core concepts are reviewed here and in arXiv:1203.3542.


title: Indistinguishability of thermal and quantum fluctuations

abstract:
  The existence of Davies-Unruh temperature in a uniformly accelerated frame
shows that quantum fluctuations of the inertial vacuum state appears as thermal
fluctuations in the accelerated frame. Hence thermodynamic experiments cannot
distinguish between phenomena occurring in a thermal bath of temperature T in
the inertial frame from those in a frame accelerating through inertial vacuum
with the acceleration $a=2\pi T$. We show that this indisguishability between
quantum fluctuations and thermal fluctuations goes far beyond the fluctuations
in the vacuum state. We show by an exact calculation, that the reduced density
matrix for a uniformly accelerated observer when the quantum field is in a
thermal state of temperature $T^\prime$ is symmetric between acceleration
temperature $T = a/(2\pi)$ and the thermal bath temperature $T^\prime$. Thus
thermal phenomena cannot distinguish whether (i) one is accelerating with $a =
2\pi T$ through a bath of temperature $T^\prime$ or (ii) accelerating with
$a=2\pi T^\prime$ through a bath of temperature T. This shows that thermal and
quantum fluctuations in an accelerated frame affect the observer in a symmetric
manner. The implications are discussed.


title: Shedding Light on the Matter of Abell 781

abstract:
  The galaxy cluster Abell 781 West has been viewed as a challenge to weak
gravitational lensing mass calibration, as Cook and dell'Antonio (2012) found
that the weak lensing signal-to-noise in three independent sets of observations
was consistently lower than expected from mass models based on X-ray and
dynamical measurements. We correct some errors in statistical inference in Cook
and dell'Antonio (2012) and show that their own results agree well with the
dynamical mass and exhibit at most 2.2--2.9$\sigma$ low compared to the X-ray
mass, similar to the tension between the dynamical and X-ray masses. Replacing
their simple magnitude cut with weights based on source photometric redshifts
eliminates the tension between lensing and X-ray masses; in this case the weak
lensing mass estimate is actually higher than, but still in agreement with, the
dynamical estimate. A comparison of lensing analyses with and without
photometric redshifts shows that a 1--2$\sigma$ chance alignment of
low-redshift sources lowers the signal-to-noise observed by all previous
studies which used magnitude cuts rather than photometric redshifts. The
fluctuation is unexceptional, but appeared to be highly significant in Cook and
dell'Antonio (2012) due to the errors in statistical interpretation.


title: A proposal for a Bohmian ontology of quantum gravity

abstract:
  The paper shows how the Bohmian approach to quantum physics can be applied to
develop a clear and coherent ontology of non-perturbative quantum gravity. We
suggest retaining discrete objects as the primitive ontology also when it comes
to a quantum theory of space-time and therefore focus on loop quantum gravity.
We conceive atoms of space, represented in terms of nodes linked by edges in a
graph, as the primitive ontology of the theory and show how a non-local law in
which a universal and stationary wave-function figures can provide an order of
configurations of such atoms of space such that the classical space-time of
general relativity is approximated. Although there is as yet no fully worked
out physical theory of quantum gravity, we regard the Bohmian approach as
setting up a standard that proposals for a serious ontology in this field
should meet and as opening up a route for fruitful physical and mathematical
investigations.


title:
Verification of Semantically-Enhanced Artifact Systems (Extended
  Version)

abstract:
  Artifact-Centric systems have emerged in the last years as a suitable
framework to model business-relevant entities, by combining their static and
dynamic aspects. In particular, the Guard-Stage-Milestone (GSM) approach has
been recently proposed to model artifacts and their lifecycle in a declarative
way. In this paper, we enhance GSM with a Semantic Layer, constituted by a
full-fledged OWL 2 QL ontology linked to the artifact information models
through mapping specifications. The ontology provides a conceptual view of the
domain under study, and allows one to understand the evolution of the artifact
system at a higher level of abstraction. In this setting, we present a
technique to specify temporal properties expressed over the Semantic Layer, and
verify them according to the evolution in the underlying GSM model. This
technique has been implemented in a tool that exploits state-of-the-art
ontology-based data access technologies to manipulate the temporal properties
according to the ontology and the mappings, and that relies on the GSMC model
checker for verification.


title:
Near-infrared adaptive optics imaging of infrared luminous galaxies: the
  brightest cluster magnitude - star formation rate relation

abstract:
  We have established a relation between the brightest super star cluster
magnitude in a galaxy and the host star formation rate (SFR) for the first time
in the near infrared (NIR). The data come from a statistical sample of ~ 40
luminous IR galaxies (LIRGs) and starbursts utilizing K-band adaptive optics
imaging. While expanding the observed relation to longer wavelengths, less
affected by extinction effects, it also pushes to higher SFRs. The relation we
find, M_K ~ - 2.6 log SFR, is similar to that derived previously in the optical
and at lower SFRs. It does not, however, fit the optical relation with a single
optical to NIR color conversion, suggesting systematic extinction and/or age
effects. While the relation is broadly consistent with a size-of-sample
explanation, we argue physical reasons for the relation are likely as well. In
particular, the scatter in the relation is smaller than expected from pure
random sampling strongly suggesting physical constraints. We also derive a
quantifiable relation tying together cluster-internal effects and host SFR
properties to possibly explain the observed brightest SSC magnitude vs. SFR
dependency.


title:
Distribution function approach to redshift space distortions. Part V:
  perturbation theory applied to dark matter halos

abstract:
  Numerical simulations show that redshift space distortions (RSD) introduce
strong scale dependence in the power spectra of halos, with ten percent
deviations relative to linear theory predictions even on relatively large
scales (k<0.1h/Mpc) and even in the absence of satellites (which induce
Fingers-of-God, FoG, effects). If unmodeled these effects prevent one from
extracting cosmological information from RSD surveys. In this paper we use
perturbation theory (PT) and halo biasing model and apply it to the
distribution function approach to RSD, in which RSD is decomposed into several
correlators of density weighted velocity moments. We model each of these
correlators using PT and compare the results to simulations over a wide range
of halo masses and redshifts. We find that with an introduction of a physically
motivated halo biasing, and using dark matter power spectra from simulations,
we can reproduce the simulation results at a percent level on scales up to
k~0.15h/Mpc at z=0, without the need to have free FoG parameters in the model.


title: Robustness of community structure to node removal

abstract:
  The identification of modular structures is essential for characterizing real
networks formed by a mesoscopic level of organization where clusters contain
nodes with a high internal degree of connectivity. Many methods have been
developed to unveil community structures, but only a few studies have probed
their suitability in incomplete networks. Here we assess the accuracy of
community detection techniques in incomplete networks generated in sampling
processes. We show that the walktrap and fast greedy algorithms are highly
accurate for detecting the modular structure of incomplete complex networks
even if many of their nodes are removed. Furthermore, we implemented an
approach that improved the time performance of the walktrap and fast greedy
algorithms, while retaining the accuracy rate in identifying the community
membership of nodes. Taken together our results show that this new approach can
be applied to speed up virtually any community detection method in dense
complex networks, as it is the case of similarity networks.


title:
On the evolution of the momentarily static radiation free data in the
  Apostolatos - Thorne cylindrical shell model

abstract:
  We study the evolution of the "Momentarily Static and Radiation Free" (MSRF)
initial data for the Apostolatos - Thorne cylindrical shell model. We analyze
the relation between the parameters characterizing the MSRF data those for the
corresponding final static configuration, and show that there is a priori no
conflict for any choice of initial MSRF data, in contrast with some recent
results of Nakao, Ida and Kurita. We also consider the problem in the linear
approximation, and show that the evolution is stable in all cases. We find that
the approach to the final state is very slow, with an inverse logarithmic
dependence on time at fixed radius. To complement these results we introduce a
numerical computation procedure that allows us to visualize the explicit form
of the evolution of the shell and of the gravitational field up to large times.
The results are in agreement with the qualitative behaviour conjectured by
Apostolatos and Thorne, with an initial damped oscillatory stage, but with
oscillations about a position that approaches slowly that of the static final
state, as indicated by our analysis. We also include an Appendix, where we
prove the existence of solutions of the cylindrical wave equation with
vanishing initial value for $r > R_0$, ($R_0 > 0$ some finite constant), that
approach a constant value for large times. This result is crucial for the proof
of compatibility of arbitrary MSRF initial data and a final static
configuration for the system.


title: Crowdsourcing a Word-Emotion Association Lexicon

abstract:
  Even though considerable attention has been given to the polarity of words
(positive and negative) and the creation of large polarity lexicons, research
in emotion analysis has had to rely on limited and small emotion lexicons. In
this paper we show how the combined strength and wisdom of the crowds can be
used to generate a large, high-quality, word-emotion and word-polarity
association lexicon quickly and inexpensively. We enumerate the challenges in
emotion annotation in a crowdsourcing scenario and propose solutions to address
them. Most notably, in addition to questions about emotions associated with
terms, we show how the inclusion of a word choice question can discourage
malicious data entry, help identify instances where the annotator may not be
familiar with the target term (allowing us to reject such annotations), and
help obtain annotations at sense level (rather than at word level). We
conducted experiments on how to formulate the emotion-annotation questions, and
show that asking if a term is associated with an emotion leads to markedly
higher inter-annotator agreement than that obtained by asking if a term evokes
an emotion.


title: Filaments in Simulations of Molecular Cloud Formation

abstract:
  We report on the filaments that develop self-consistently in a new numerical
simulation of cloud formation by colliding flows. As in previous studies, the
forming cloud begins to undergo gravitational collapse because it rapidly
acquires a mass much larger than the average Jeans mass. Thus, the collapse
soon becomes nearly pressureless, proceeding along its shortest dimension
first. This naturally produces filaments in the cloud, and clumps within the
filaments. The filaments are not in equilibrium at any time, but instead are
long-lived flow features, through which the gas flows from the cloud to the
clumps. The filaments are long-lived because they accrete from their
environment while simultaneously accreting onto the clumps within them; they
are essentially the locus where the flow changes from accreting in two
dimensions to accreting in one dimension. Moreover, the clumps also exhibit a
hierarchical nature: the gas in a filament flows onto a main, central clump,
but other, smaller-scale clumps form along the infalling gas. Correspondingly,
the velocity along the filament exhibits a hierarchy of jumps at the locations
of the clumps. Two prominent filaments in the simulation have lengths ~15 pc,
and masses ~600 Msun above density n ~ 10^3 cm-3 (~2x10^3 Msun at n > 50 cm-3).
The density profile exhibits a central flattened core of size ~0.3 pc and an
envelope that decays as r^-2.5, in reasonable agreement with observations.
Accretion onto the filament reaches a maximum linear density rate of ~30 Msun
Myr^-1 pc^-1.


title: SUSY_FLAVOR library for rare decays in the MSSM

abstract:
  SUSY_FLAVOUR 2.0 is a FORTRAN code calculating over 30 low-energy flavour-
and CP-related observables in the R-parity conserving MSSM. The code admits for
the most general flavour structure of the SUSY breaking terms and complex
flavour-diagonal couplings. It includes the numerically important resummation
of chirally enhanced effects and it is fast enough for scanning over a large
SUSY-parameter space. The program can be obtained from
http://www.fuw.edu.pl/susy_flavor.


title: Computing Lexical Contrast

abstract:
  Knowing the degree of semantic contrast between words has widespread
application in natural language processing, including machine translation,
information retrieval, and dialogue systems. Manually-created lexicons focus on
opposites, such as {\rm hot} and {\rm cold}. Opposites are of many kinds such
as antipodals, complementaries, and gradable. However, existing lexicons often
do not classify opposites into the different kinds. They also do not explicitly
list word pairs that are not opposites but yet have some degree of contrast in
meaning, such as {\rm warm} and {\rm cold} or {\rm tropical} and {\rm
freezing}. We propose an automatic method to identify contrasting word pairs
that is based on the hypothesis that if a pair of words, $A$ and $B$, are
contrasting, then there is a pair of opposites, $C$ and $D$, such that $A$ and
$C$ are strongly related and $B$ and $D$ are strongly related. (For example,
there exists the pair of opposites {\rm hot} and {\rm cold} such that {\rm
tropical} is related to {\rm hot,} and {\rm freezing} is related to {\rm
cold}.) We will call this the contrast hypothesis. We begin with a large
crowdsourcing experiment to determine the amount of human agreement on the
concept of oppositeness and its different kinds. In the process, we flesh out
key features of different kinds of opposites. We then present an automatic and
empirical measure of lexical contrast that relies on the contrast hypothesis,
corpus statistics, and the structure of a {\it Roget}-like thesaurus. We show
that the proposed measure of lexical contrast obtains high precision and large
coverage, outperforming existing methods.


title:
Examining the physical principles behind the motion of moist air: Which
  expressions are sound?

abstract:
  The physical equations determining the motion of moist atmospheric air in the
presence of condensation remain controversial. Two distinct formulations have
been proposed, published and cited. The equation of Bannon [2002, J. Atmos.
Sci. 59: 1967--1982] includes a term for a "reactive motion" that arises when
water vapor condenses and droplets begin to fall; according to this term the
remaining gas moves upwards so as to conserve momentum. In the equation of
Ooyama[2001, J. Atmos. Sci. 58: 2073--2102] the reactive motion term is absent.
Both equations contain a term for condensate loading, but in the formulation of
Ooyama [2001] there are two additional terms. In some modern nonhydrostatic
models of moist atmospheric circulation, however, formulations have been mixed.
Here we examine the contrasting equations for the motion of moist air. We
discuss inconsistencies in the application of Newton's second and third laws to
an air and condensate mixture. We show that the concept of reactive motion in
this context is based on a misunderstanding of the conservation of momentum in
the presence of a gravitational field: such a reactive motion does not exist.
We show that the "mixed" equation used in some models is not physically
consistent either. We examine why consideration of total momentum, that is air
and condensate combined, has been misleading in the search for valid equations
of motion in the presence of phase transitions.


title:
Studies of measuring Higgs self-coupling with $HH\rightarrow b\bar b
  \gamma\gamma$ at the future hadron colliders

abstract:
  We present a feasibility study of observing $HH\rightarrow b\bar
b\gamma\gamma$ at the future hadron colliders with $\sqrt{s}=$14, 33, and 100
TeV. The measured cross section then can be used to constrain the Higgs
self-coupling directly in the standard model. Any deviation could be a sign of
new physics. The signal and background events are estimated using Delphes
3.0.10 fast Monte Carlo simulation based on the ATLAS detector capabilities.
With 3 ab$^{-1}$ data, it would be possible to measure the Higgs self-coupling
with a 50%, 20%, and 8% statistical accuracy by observing $HH\rightarrow b\bar
b\gamma\gamma$ at $\sqrt{s}=$14, 33, and 100 TeV colliders, respectively.


title: Uncovering the Specific Product Rule for the Lattice of Questions

abstract:
  We give here the specific product rule for the lattice of questions. This
product rule differs from the product rule for the lattice of statements, hence
the qualifier `specific'. This is because the elements in the lattice of
statements are ordered by way of implication, an upper context, whereas the
elements in the lattice of questions are ordered by way of relevancy, a lower
context.


title: Non-$\gamma_{5}$hermiticity fermions in two dimensions

abstract:
  We construct 2D non-$\gamma_{5}$hermiticity fermions based on the minimal
doubling fermion. We investigate symmetries, reflection positivity, eigenvalue
distribution and the number of poles for our fermions. As simple tests for
application to the fermion, the Gross-Neveu model in two dimensions is studied
using the non-$\gamma_{5}$hermiticity fermion. We draw the parity broken phase
diagram, called Aoki phase and the chiral broken phase diagram for the model
with an imaginary chemical potential.


title:
High-order harmonic generation from Rydberg states at fixed Keldysh
  parameter

abstract:
  Because the commonly adopted viewpoint that the Keldysh parameter $\gamma $
determines the dynamical regime in strong field physics has long been
demonstrated to be misleading, one can ask what happens as relevant physical
parameters, such as laser intensity and frequency, are varied while $\gamma$ is
kept fixed. We present results from our one- and fully three-dimensional
quantum simulations of high-order harmonic generation (HHG) from various bound
states of hydrogen with $n$ up to 40, where the laser intensities and the
frequencies are scaled from those for $n=1$ in order to maintain a fixed
Keldysh parameter $\gamma$$< 1$ for all $n$. We find that as we increase $n$
while keeping $\gamma $ fixed, the position of the cut-off scales in well
defined manner. Moreover, a secondary plateau forms with a new cut-off,
splitting the HHG plateau into two regions. First of these sub-plateaus is
composed of lower harmonics, and has a higher yield than the second one. The
latter extends up to the semiclassical $I_p+3.17U_p$ cut-off. We find that this
structure is universal, and the HHG spectra look the same for all $n\gtrsim 10$
when plotted as a function of the scaled harmonic order. We investigate the
$n$-, $l$- and momentum distributions to elucidate the physical mechanism
leading to this universal structure.


title: On the Brittleness of Bayesian Inference

abstract:
  With the advent of high-performance computing, Bayesian methods are
increasingly popular tools for the quantification of uncertainty throughout
science and industry. Since these methods impact the making of sometimes
critical decisions in increasingly complicated contexts, the sensitivity of
their posterior conclusions with respect to the underlying models and prior
beliefs is a pressing question for which there currently exist positive and
negative results. We report new results suggesting that, although Bayesian
methods are robust when the number of possible outcomes is finite or when only
a finite number of marginals of the data-generating distribution are unknown,
they could be generically brittle when applied to continuous systems (and their
discretizations) with finite information on the data-generating distribution.
If closeness is defined in terms of the total variation metric or the matching
of a finite system of generalized moments, then (1) two practitioners who use
arbitrarily close models and observe the same (possibly arbitrarily large
amount of) data may reach opposite conclusions; and (2) any given prior and
model can be slightly perturbed to achieve any desired posterior conclusions.
The mechanism causing brittlenss/robustness suggests that learning and
robustness are antagonistic requirements and raises the question of a missing
stability condition for using Bayesian Inference in a continuous world under
finite information.


title:
Single top quark cross section measurement in the t-channel at the
  high-luminosity LHC

abstract:
  We study the precision with which the t-channel single top quark production
cross section is expected to be measured in future LHC runs at 14 TeV. The
single top final state has a lepton and neutrino from the top quark decay plus
two jets, one of which is required to be b-tagged. This measurement is done in
the context of the Snowmass 2013 study for the low-luminosity 14 TeV and the
high-luminosity 14 TeV LHC as well as for high-luminosity 33 TeV LHC.


title:
Below One Earth Mass: The Detection, Formation, and Properties of
  Subterrestrial Worlds

abstract:
  The Solar System includes two planets --- Mercury and Mars --- significantly
less massive than Earth, and all evidence indicates that planets of similar
size orbit many stars. In fact, one of the first exoplanets to be discovered is
a lunar-mass planet around a millisecond pulsar. Novel classes of exoplanets
have inspired new ideas about planet formation and evolution, and these
"sub-Earths" should be no exception: they include planets with masses between
Mars and Venus for which there are no Solar System analogs. Advances in
astronomical instrumentation and recent space missions have opened the
sub-Earth frontier for exploration: the Kepler mission has discovered dozens of
confirmed or candidate sub-Earths transiting their host stars. It can detect
Mars-size planets around its smallest stellar targets, as well as exomoons of
comparable size. Although the application of the Doppler method is currently
limited by instrument stability, future spectrographs may detect equivalent
planets orbiting close to nearby bright stars. Future space-based microlensing
missions should be able to probe the sub-Earth population on much wider orbits.
A census of sub-Earths will complete the reconnaissance of the exoplanet mass
spectrum and test predictions of planet formation models, including whether
low-mass M dwarf stars preferentially host the smallest planets. The properties
of sub-Earths may reflect their low gravity, diverse origins, and environment,
but they will be elusive: Observations of eclipsing systems by the James Webb
Space Telescope may give us our first clues to the properties of these small
worlds.


title: Text recognition in both ancient and cartographic documents

abstract:
  This paper deals with the recognition and matching of text in both
cartographic maps and ancient documents. The purpose of this work is to find
similar text regions based on statistical and global features. A phase of
normalization is done first, in object to well categorize the same quantity of
information. A phase of wordspotting is done next by combining local and global
features. We make different experiments by combining the different techniques
of extracting features in order to obtain better results in recognition phase.
We applied fontspotting on both ancient documents and cartographic ones. We
also applied the wordspotting in which we adopted a new technique which tries
to compare the images of character and not the entire images words. We present
the precision and recall values obtained with three methods for the new method
of wordspotting applied on characters only.


title: Qubit noise spectroscopy using a continuous driving field

abstract:
  The optimization of dynamical decoupling and quantum error correction for a
particular qubit realization is based on a detailed knowledge of the noise
properties. Spectroscopy of single-axis noise using dynamical decoupling pulse
sequences has garnered much recent attention. Here we consider noise
spectroscopy based on a spin-locking type pulse sequence, i.e. a
continuous-wave (CW) on-resonance driving field. We show that a heuristic
filter function approach produces a qualitatively correct (but quantitatively
incorrect) result, whereas a 0th-order average Hamiltonian calculation is shown
to agree with the result predicted by the generalized Bloch equations. We
further calculate up to 2nd-order average Hamiltonian corrections and show the
deviation from the generalized Bloch equation result. This shows that noise
spectroscopy using continuous fields, in some cases simpler to implement and
more robust to errors than pulsed schemes, can be rigorously analyzed and
criteria for reliable measurements can be established. Finally, a solid-state
nuclear magnetic resonance experiment is presented which demonstrates that the
CW and pulsed methods agree within experimental error. The noise, due to
magnetization fluctuations in a dipolar coupled proton spin bath, is found to
obey a roughly 1/\omega\ power law decay in the range of frequencies \omega\
investigated.


title: Categorizing ancient documents

abstract:
  The analysis of historical documents is still a topical issue given the
importance of information that can be extracted and also the importance given
by the institutions to preserve their heritage. The main idea in order to
characterize the content of the images of ancient documents after attempting to
clean the image is segmented blocks texts from the same image and tries to find
similar blocks in either the same image or the entire image database. Most
approaches of offline handwriting recognition proceed by segmenting words into
smaller pieces (usually characters) which are recognized separately.
Recognition of a word then requires the recognition of all characters (OCR)
that compose it. Our work focuses mainly on the characterization of classes in
images of old documents. We use Som toolbox for finding classes in documents.
We applied also fractal dimensions and points of interest to categorize and
match ancient documents.


title:
Evidence of bias in the Eurovision song contest: modelling the votes
  using Bayesian hierarchical models

abstract:
  The Eurovision Song Contest is an annual musical competition held among
active members of the European Broadcasting Union since 1956. The event is
televised live across Europe. Each participating country presents a song and
receive a vote based on a combination of tele-voting and jury. Over the years,
this has led to speculations of tactical voting, discriminating against some
participants and thus inducing bias in the final results. In this paper we
investigate the presence of positive or negative bias (which may roughly
indicate favouritisms or discrimination) in the votes based on geographical
proximity, migration and cultural characteristics of the participating
countries through a Bayesian hierarchical model. Our analysis found no evidence
of negative bias, although mild positive bias does seem to emerge
systematically, linking voters to performers.


title: A Low Metallicity Molecular Cloud In The Lower Galactic Halo

abstract:
  We find evidence for the impact of infalling, low-metallicity gas on the
Galactic disk. This is based on FUV absorption line spectra, 21-cm emission
line spectra, and FIR mapping to estimate the abundance and physical properties
of IV21 (IVC135+54-45), a galactic intermediate-velocity molecular cloud (IVMC)
that lies ~300 pc above the disk. The metallicity of IV21 was estimated using
observations toward the sdB star PG1144+615, located at a projected distance of
16 pc from the cloud's densest core, by measuring ion and HI column densities
for comparison with known solar abundances. Despite the cloud's bright FIR
emission and large column densities of molecular gas as traced by CO, we find
that it has a sub-solar metallicity of log(Z/Z_Sun)=-0.43 +/- 0.12dex. IV21 is
thus the first known sub-solar metallicity cloud in the solar neighborhood. In
contrast, most intermediate-velocity clouds (IVC) have near-solar metallicities
and are believed to originate in the Galactic Fountain. The cloud's low
metallicity is also atypical for Galactic molecular clouds, especially in the
light of the bright FIR emission which suggest a substantial dust content. The
measured I_100mu/N(HI) ratio is a factor of three below the average found in
high latitude \HI clouds within the solar neighborhood. We argue that IV21
represents the impact of an infalling, low-metallicity high-velocity cloud
(HVC) that is mixing with disk gas in the lower Galactic halo.


title:
Magneto-tunnelling spectroscopy of chiral two-dimensional electron
  systems

abstract:
  We present a theoretical study of momentum-resolved tunneling between
parallel two-dimensional conductors whose charge carriers have a
(pseudo-)spin-1/2 degree of freedom that is strongly coupled to their linear
orbital momentum. Specific examples are single and bilayer graphene as well as
single-layer molybdenum disulphide. Resonant behavior of the differential
tunneling conductance exhibited as a function of an in-plane magnetic field and
bias voltage is found to be strongly affected by the (pseudo-)spin structure of
the tunneling matrix. We discuss ramifications for the direct measurement of
electronic properties such as Fermi surfaces and the dispersion curves.
Furthermore, using a graphene double-layer structure as an example, we show how
magneto-tunneling transport can be used to measure the pseudo-spin structure of
tunnel matrix elements, thus enabling electronic characterization of the
barrier material.


title:
Clustering, Classification, Discriminant Analysis, and Dimension
  Reduction via Generalized Hyperbolic Mixtures

abstract:
  A method for dimension reduction with clustering, classification, or
discriminant analysis is introduced. This mixture model-based approach is based
on fitting generalized hyperbolic mixtures on a reduced subspace within the
paradigm of model-based clustering, classification, or discriminant analysis. A
reduced subspace of the data is derived by considering the extent to which
group means and group covariances vary. The members of the subspace arise
through linear combinations of the original data, and are ordered by importance
via the associated eigenvalues. The observations can be projected onto the
subspace, resulting in a set of variables that captures most of the clustering
information available. The use of generalized hyperbolic mixtures gives a
robust framework capable of dealing with skewed clusters. Although dimension
reduction is increasingly in demand across many application areas, the authors
are most familiar with biological applications and so two of the five real data
examples are within that sphere. Simulated data are also used for illustration.
The approach introduced herein can be considered the most general such approach
available, and so we compare results to three special and limiting cases.
Comparisons with several well established techniques illustrate its promising
performance.


title: Retroactive Anti-Jamming for MISO Broadcast Channels

abstract:
  Jamming attacks can significantly impact the performance of wireless
communication systems. In addition to reducing the capacity, such attacks may
lead to insurmountable overhead in terms of re-transmissions and increased
power consumption. In this paper, we consider the multiple-input single-output
(MISO) broadcast channel (BC) in the presence of a jamming attack in which a
subset of the receivers can be jammed at any given time. Further,
countermeasures for mitigating the effects of such jamming attacks are
presented. The effectiveness of these anti-jamming countermeasures is
quantified in terms of the degrees-of-freedom (DoF) of the MISO BC under
various assumptions regarding the availability of the channel state information
(CSIT) and the jammer state information at the transmitter (JSIT). The main
contribution of this paper is the characterization of the DoF region of the two
user MISO BC under various assumptions on the availability of CSIT and JSIT.
Partial extensions to the multi-user broadcast channels are also presented.


title: The Past, Present and Future of Cybernetics and Systems Research

abstract:
  Cybernetics and Systems Research (CSR) were developed in the mid-twentieth
century, offering the possibility of describing and comparing different
phenomena using the same language. The concepts which originated in CSR have
spread to practically all disciplines, many now used within the scientific
study of complex systems. CSR has the potential to contribute to the solution
of relevant problems, but the path towards this goal is not straightforward.
This paper summarizes the ideas presented by the authors during a round table
in 2012 on the past, present and future of CSR.


title: Aspects of Classical Descriptive Set Theory

abstract:
  This report consists of two parts. The first part is a brief exposition of
classical descriptive set theory. This part introduces some fundamental
concepts, motivations and results from the classical theory and ends with a
section on the important result of Addison that established the correspondence
between classical and effective notions. The second part is about invariant
descriptive set theory. It consists of a brief introduction to notions relevant
to this branch of descriptive set theory and then describes in details some of
the relatively recent results concerning equivalence relations between Polish
metric spaces.


title:
A proposition of a robust system for historical document images
  indexation

abstract:
  Characterizing noisy or ancient documents is a challenging problem up to now.
Many techniques have been done in order to effectuate feature extraction and
image indexation for such documents. Global approaches are in general less
robust and exact than local approaches. That's why, we propose in this paper, a
hybrid system based on global approach(fractal dimension), and a local one
based on SIFT descriptor. The Scale Invariant Feature Transform seems to do
well with our application since it's rotation invariant and relatively robust
to changing illumination.In the first step the calculation of fractal dimension
is applied to images in order to eliminate images which have distant features
than image request characteristics. Next, the SIFT is applied to show which
images match well the request. However the average matching time using the
hybrid approach is better than "fractal dimension" and "SIFT descriptor" if
they are used alone.


title:
Three-Dimensional Mapped-Grid Finite Volume Modeling of
  Poroelastic-Fluid Wave Propagation

abstract:
  This paper extends the author's previous two-dimensional work with Ou and
LeVeque to high-resolution finite volume modeling of systems of fluids and
poroelastic media in three dimensions, using logically rectangular mapped
grids. A method is described for calculating consistent cell face areas and
normal vectors for a finite volume method on a general non-rectilinear
hexahedral grid. A novel limiting algorithm is also developed to cope with
difficulties encountered in implementing high-resolution finite volume methods
for anisotropic media on non-rectilinear grids; the new limiting approach is
compatible with any limiter function, and typically reduces solution error even
in situations where it is not necessary for correct functioning of the
numerical method. Dimensional splitting is used to reduce the computational
cost of the solution. The code implementing the three-dimensional algorithms is
verified against known plane wave solutions, with particular attention to the
performance of the new limiter algorithm in comparison to the classical one. An
acoustic wave in brine striking an uneven bed of orthotropic layered sandstone
is also simulated in order to demonstrate the capabilities of the simulation
code.


title:
A Systematic Look at the Effects of Radiative Feedback on Disc Galaxy
  Formation

abstract:
  Galaxy formation models and simulations rely on various feedback mechanisms
to reproduce the observed baryonic scaling relations and galaxy morphologies.
Although dwarf galaxy and giant elliptical properties can be explained using
feedback from supernova and active galactic nuclei, Milky Way-sized galaxies
still represent a challenge to current theories of galaxy formation. In this
paper, we explore the possible role of feedback from stellar radiation in
regulating the main properties of disk galaxies such as our own Milky Way. We
have performed a suite of cosmological simulations of the same $\sim10^{12}
{\rm M}_{\odot}$ halo selected based on its rather typical mass accretion
history. We have implemented radiative feedback from young stars using a crude
model of radiative transfer for ultraviolet (UV) and infrared (IR) radiation.
However, the model is realistic enough such that the dust opacity plays a
direct role in regulating the efficiency of our feedback mechanism. We have
explored various models for the dust opacity, assuming different constant dust
temperatures, as well as a varying dust temperature model. We find that while
strong radiative feedback appears as a viable mechanism to regulate the stellar
mass fraction in massive galaxies, it also prevents the formation of discs with
reasonable morphologies. In models with strong stellar radiation feedback,
stellar discs are systematically too thick while the gas disc morphology is
completely destroyed due to the efficient mixing between the feedback-affected
gas and its surroundings. At the resolution of our simulation suite, we find it
impossible to preserve spiral disc morphology while at the same time expelling
enough baryons to satisfy the abundance matching constraints.


title:
What do observations of the Lyman-alpha fraction tell us about
  reionization?

abstract:
  An appealing approach for studying the reionization history of the Universe
is to measure the redshift evolution of the Lyman-alpha fraction, the
percentage of Lyman-break selected galaxies that emit appreciably in the
Ly-alpha line. This fraction is expected to fall-off towards high redshift as
the intergalactic medium becomes significantly neutral, and the galaxies'
Ly-alpha emission is progressively attenuated. Intriguingly, early measurements
with this technique suggest a strong drop in the Ly-alpha fraction near z ~ 7.
Previous work concluded that this requires a surprisingly neutral intergalactic
medium -- with neutral hydrogen filling more than 50 % of the volume of the
Universe -- at this redshift. We model the evolving Ly-alpha fraction using
cosmological simulations of the reionization process. Before reionization
completes, the simulated Ly-alpha fraction has large spatial fluctuations owing
to the inhomogeneity of reionization. Since existing measurements of the
Ly-alpha fraction span relatively small regions on the sky, and sample these
regions only sparsely, they may by chance probe mostly galaxies with above
average Ly-alpha attenuation. We find that this sample variance is not
exceedingly large for existing surveys, but that it does somewhat mitigate the
required neutral fraction at z ~ 7. Quantitatively, in a fiducial model
calibrated to match measurements after reionization, we find that current z = 7
observations require a volume-averaged neutral fraction of x_HI > 0.05 at 95 %
confidence level. Hence, we find that the z ~ 7 Ly-alpha fraction measurements
do likely probe the Universe before reionization completes but that they do not
require a very large neutral fraction.


title:
A basis of dimension-eight operators for anomalous neutral triple gauge
  boson interactions

abstract:
  Four independent dimension-eight operators give rise to anomalous neutral
triple gauge boson interactions, one CP-even and three CP-odd. Only the CP-even
operator interferes with the Standard Model for the production of a pair of
on-shell neutral bosons. However, the effects are found to be tiny due mainly
to the mismatch of the Z boson polarization between the productions from the SM
and the new operator.


title:
Prediction of breast cancer recurrence using Classification Restricted
  Boltzmann Machine with Dropping

abstract:
  In this paper, we apply Classification Restricted Boltzmann Machine
(ClassRBM) to the problem of predicting breast cancer recurrence. According to
the Polish National Cancer Registry, in 2010 only, the breast cancer caused
almost 25% of all diagnosed cases of cancer in Poland. We propose how to use
ClassRBM for predicting breast cancer return and discovering relevant inputs
(symptoms) in illness reappearance. Next, we outline a general probabilistic
framework for learning Boltzmann machines with masks, which we refer to as
Dropping. The fashion of generating masks leads to different learning methods,
i.e., DropOut, DropConnect. We propose a new method called DropPart which is a
generalization of DropConnect. In DropPart the Beta distribution instead of
Bernoulli distribution in DropConnect is used. At the end, we carry out an
experiment using real-life dataset consisting of 949 cases, provided by the
Institute of Oncology Ljubljana.


title: 26Al in the Early Solar System: Not so Unusual After All

abstract:
  Recently acquired evidence shows that extrasolar asteroids exhibit over a
factor of 100 variation in the iron to aluminum abundance ratio. This large
range likely is a consequence of igneous differentiation that resulted from
heating produced by radioactive decay of 26Al with an abundance comparable to
that in the solar system's protoplanetary disk at birth. If so, the
conventional view that our solar system began with an unusually high amount of
26Al should be discarded.


title: Patterson-Sullivan measures and growth of relatively hyperbolic groups

abstract:
  We prove that for a relatively hyperbolic group G there is a sequence of
relatively hyperbolic proper quotients such that their growth rates converge to
the growth rate of G. Under natural assumptions, the same conclusion holds for
the critical exponent of a cusp-uniform action of G on a hyperbolic metric
space. As a corollary, we obtain that the critical exponent of a torsion-free
geometrically finite Kleinian group can be arbitrarily approximated by those of
quotient groups. This resolves a question of Dal'bo-Peign\'e-Picaud-Sambusetti.
  Our approach is based on the study of Patterson-Sullivan measures on Bowditch
boundary of a relatively hyperbolic group. The uniqueness and ergodicity of
Patterson-Sullivan measures are proved when the group is divergent. We prove a
variant of the Sullivan Shadow Lemma, called Partial Shadow Lemma. This tool
allows us to prove several results on growth functions of balls and cones. One
central result is the existence of a sequence of geodesic trees with growth
rates sufficiently close to the growth rate of G, and transition points
uniformly spaced in trees. By taking small cancellation over hyperbolic
elements of high powers, we can embed these trees into properly constructed
quotients of G. This proves the results in the previous paragraph.


title:
Distribution of local relaxation events in an aging 3D glass:
  spatio-temporal correlation and dynamical heterogeneity

abstract:
  We investigate the spatio-temporal distribution of microscopic relaxation
events, defined through particle hops, in a model polymer glass using molecular
dynamics simulations. We introduce an efficient algorithm to directly identify
hops during the simulation, which allows the creation of a map of relaxation
events for the whole system. Based on this map, we present density-density
correlations between hops and directly extract correlation scales. These scales
define collaboratively rearranging groups of particles and their size
distributions are presented as a function of temperature and age. Dynamical
heterogeneity is spatially resolved as the aggregation of hops into clusters,
and we analyze their volume distribution and growth during aging. A direct
comparison with the four-point dynamical susceptibility {\chi}4 reveals the
formation of a single dominating cluster prior to the {\chi}4 peak, which
indicates maximally correlated dynamics. An analysis of the fractal dimension
of the hop clusters finds slightly non-compact shapes in excellent agreement
with independent estimates from four-point correlations.


title: Recent Kepler Results On Circumbinary Planets

abstract:
  Ranked near the top of the long list of exciting discoveries made with NASA's
Kepler photometer is the detection of transiting circumbinary planets. In just
over a year the number of such planets went from zero to seven, including a
multi-planet system with one of the planets in the habitable zone (Kepler-47).
We are quickly learning to better detect and characterize these planets,
including the recognition of their transit timing and duration variation
"smoking gun" signature. Even with only a handful of such planets, some
exciting trends are emerging.


title:
Indecomposable characters of infinite dimensional groups associated with
  operator algebras

abstract:
  We determine the indecomposable characters of several classes of infinite
dimensional groups associated with operator algebras, including the unitary
groups of arbitrary unital simple AF algebras and II$_1$ factors.


title:
Limit groups with respect to Thompson's group F and other finitely
  generated groups

abstract:
  Let F be the (Thompson's) group < x_0, x_1 | [x_0x_1^-1, x_0^-ix_1 x_0^i],
i=1,2 >. We study the structure of F-limit groups. Let G_n= < y_1,..., y_m,
x_0,x_1 | [x_0x_1^-1,x_0^-1x_1x_0],[x_0x_1^-1,x_0^-2x_1x_0^2],
y_j^-1g_j,n(x_0,x_1), 0<j<m+1 >, where g_j,n(x_0,x_1) belongs to F, be a family
of groups marked by m+2 elements. If the sequence (G_n)_n<w is convergent in
the space of marked groups and G is the corresponding limit we say that G is an
F-limit group. Primarily the paper is devoted to the study of F-limit groups.
  The results are based on some theorems concerning laws with parameters in F.
In particular several constructions of such laws are given. On the other hand
we formulate some very general conditions on words with parameters
w(y,a_1,...,a_n) over F which guarantee that the inequality w(y,a') is not
equal to 1 has a solution in F.
  Some of the results are of a more general nature and can be applied to study
limit groups with respect to other finitely generated groups and classes of
finitely generated groups, in particular to the case of the Grigorchuk group.


title:
Quantum phase diagram of the $S=1/2$ triangular-lattice antiferromagnet
  Ba$_3$CoSb$_2$O$_9$

abstract:
  The magnetic phases of the ideal spin-1/2 triangular-lattice antiferromagnet
Ba$_3$CoSb$_2$O$_9$ are identified and studied using $^{135,137}$Ba nuclear
magnetic resonance (NMR) spectroscopy in magnetic fields ranging to 30T,
oriented parallel and near perpendicular to the crystallographic $ab$-plane.
For both directions, the saturation field is approximately 33T. Notably, the
NMR spectra provide microscopic evidence for the stabilization of an up-up-down
spin configuration for in-plane fields, giving rise to an one-third
magnetization plateau ($M_\text{sat}/3$), as well as for a higher field phase
transition near to $\sim (3/5)M_\text{sat}$ for both field orientations. Phase
transitions are signaled by the evolution of the NMR spectra, and in some cases
through spin-lattice relaxation measurements. The results are compared with
expectations obtained from a semi-classical energy density modeling, in which
quantum effects are incorporated by effective interactions extracted from the
spin-wave analysis of the two-dimensional model. The interlayer coupling also
plays a significant role in the outcome. Good agreement between the model and
the experimental results is achieved, except for the case of fields approaching
the saturation value applied along the c-axis.


title: Multiple Fast Molecular Outflows in the PPN CRL 618

abstract:
  CRL 618 is a well-studied pre-planetary nebula. It has multiple highly
collimated optical lobes, fast molecular outflows along the optical lobes, and
an extended molecular envelope that consists of a dense torus in the equator
and a tenuous round halo. Here we present our observations of this source in CO
J=3-2 and HCN J=4-3 obtained with the Submillimeter Array at up to ~ 0.3"
resolutions. We spatially resolve the fast molecular-outflow region previously
detected in CO near the central star and find it to be composed of multiple
outflows that have similar dynamical ages, and are oriented along the different
optical lobes. We also detect fast molecular outflows further away from the
central star near the tips of the extended optical lobes and a pair of
equatorial outflows inside the dense torus. We find that two episodes of bullet
ejections in different directions are needed, one producing the fast molecular
outflows near the central star, and one producing the fast molecular outflows
near the tips of the extended optical lobes. One possibility to launch these
bullets is the magneto-rotational explosion of the stellar envelope.


title:
TreeOTU: Operational Taxonomic Unit Classification Based on Phylogenetic
  Trees

abstract:
  Our current understanding of the taxonomic and phylogenetic diversity of
cellular organisms, especially the bacteria and archaea, is mostly based upon
studies of sequences of the small- subunit rRNAs (ssu-rRNAs). To address the
limitation of ssu-rRNA as a phylogenetic marker, such as copy number variation
among organisms and complications introduced by horizontal gene transfer,
convergent evolution, or evolution rate variations, we have identified protein-
coding gene families as alternative Phylogenetic and Phylogenetic Ecology
markers (PhyEco). Current nucleotide sequence similarity based Operational
Taxonomic Unit (OTU) classification methods are not readily applicable to amino
acid sequences of PhyEco markers. We report here the development of TreeOTU, a
phylogenetic tree structure based OTU classification method that takes into
account of differences in rates of evolution between taxa and between genes.
OTU sets built by TreeOTU are more faithful to phylogenetic tree structures
than sequence clustering (non phylogenetic) methods for ssu-rRNAs. OTUs built
from phylogenetic trees of protein coding PhyEco markers are comparable to our
current taxonomic classification at different levels. With the included OTU
comparing tools, the TreeOTU is robust in phylogenetic referencing with
different phylogenetic markers and trees.


title: Heavy Higgs Scalars at Future Hadron Colliders (A Snowmass Whitepaper)

abstract:
  We investigate the prospects for discovery or exclusion of additional Higgs
scalars at the 14 TeV and 33 TeV LHC in the context of theories with two Higgs
doublets. We focus on the modes with the largest production rates at hadron
colliders, namely gluon fusion production of a heavy CP-even scalar H or a
heavy CP-odd pseudoscalar A. We consider the sensitivity of the decay channels
H to ZZ to 4l, and A to Zh with Z to ll and h to bb or h to tautau.


title: Non-Supersymmetric, Multi-Center Solutions with Topological Flux

abstract:
  We find an infinite class of non-supersymmetric multi-center solutions to the
STU model in five-dimensional ungauged supergravity coupled to two vector
multiplets. The solutions are obtained by solving a system of linear equations
on a class of Ricci-scalar-flat K\"ahler manifolds studied by LeBrun. After
imposing an additional U(1) isometry in the base, we solve the axisymmetric
$SU(\infty)$ Toda equation and obtain explicit supergravity solutions
containing arbitrary numbers of 2-cycles with cohomological fluxes of all three
flavors. This improves upon a previous result where only two of the three
fluxes were topologically non-trivial. Imposing regularity and absence of
closed timelike curves, we obtain "bubble equations" highly reminiscent of
those known in the supersymmetric case. Thus we extend much of the analysis
done for BPS bubbling solutions to this new family of non-supersymmetric
bubbling solutions.


title:
Experimental implementation of an eight-dimensional Kochen-Specker set
  and observation of its connection with the Greenberger-Horne-Zeilinger
  theorem

abstract:
  For eight-dimensional quantum systems there is a Kochen-Specker (KS) set of
40 quantum yes-no tests that is related to the Greenberger-Horne-Zeilinger
(GHZ) proof of Bell's theorem. Here we experimentally implement this KS set
using an eight-dimensional Hilbert space spanned by the transverse momentum of
single photons. We show that the experimental results of these tests violate a
state-independent noncontextuality inequality. In addition, we show that, if
the system is prepared in states that are formally equivalent to a three-qubit
GHZ and $W$ states, then the results of a subset of 16 tests violate a
noncontextuality inequality that is formally equivalent to the three-party
Mermin's Bell inequality, but for single eight-dimensional quantum systems.
These experimental results highlight the connection between quantum
contextuality and nonlocality for eight-dimensional quantum systems.


title: A dual algorithm for a class of augmented convex models

abstract:
  Convex optimization models find interesting applications, especially in
signal/image processing and compressive sensing. We study some augmented convex
models, which are perturbed by strongly convex functions, and propose a dual
gradient algorithm. The proposed algorithm includes the linearized Bregman
algorithm and the singular value thresholding algorithm as special cases. Based
on fundamental properties of proximal operators, we present a concise approach
to establish the convergence of both primal and dual sequences, improving the
results in the existing literature.


title:
Inflation and Dark Matter in the Higgs Portal of Classically Scale
  Invariant Standard Model

abstract:
  We consider a minimal classically scale-invariant extension of the Standard
Model. In this theory, the Higgs mechanism is triggered and the electroweak
symmetry breaking is generated radiatively by the Coleman-Weinberg sector which
is coupled to the SM Higgs. We extend the Higgs portal interactions of the
theory to include an additional singlet which is also non-minimally coupled to
gravity. This generates a single-field slow-roll inflation mechanism in the
effective field theory formulation which is robust up to Planck scales. Our
approach does not require integrating in any additional new physics degrees of
freedom to unitarise the theory in the sub-Planckian regime where inflation
happens. As a result, no large threshold corrections appear in our approach to
inflation so that the electroweak scale and the SM Higgs mass are not affected.
The singlet field responsible for inflation also gives a viable dark matter
candidate in our model. We also discuss the relation between classical
scale-invariance of the effective theory and the possible local scale
invariance of the full theory and comment on the naturalness of the electroweak
scale.


title: New bounds for circulant Johnson-Lindenstrauss embeddings

abstract:
  This paper analyzes circulant Johnson-Lindenstrauss (JL) embeddings which, as
an important class of structured random JL embeddings, are formed by
randomizing the column signs of a circulant matrix generated by a random
vector. With the help of recent decoupling techniques and matrix-valued
Bernstein inequalities, we obtain a new bound
$k=O(\epsilon^{-2}\log^{(1+\delta)} (n))$ for Gaussian circulant JL embeddings.
Moreover, by using the Laplace transform technique (also called Bernstein's
trick), we extend the result to subgaussian case. The bounds in this paper
offer a small improvement over the current best bounds for Gaussian circulant
JL embeddings for certain parameter regimes and are derived using more direct
methods.


abstract:
  Pressure-induced phase transitions of multiferroic BiFeO3 have been
investigated using synchrotron radiation X-ray diffraction with diamond anvil
cell technique at room temperature. Present experimental data clearly show that
rhombohedral (R3c) phase of BiFeO3 first transforms to monoclinic (C2/m) phase
at 7 GPa, then to orthorhombic (Pnma) phase at 11 GPa, which is consistent with
recent theoretical ab initio calculation. However, we observe another peak at
2{\theta}=7{\deg} in the pressure range of 5-7 GPa that has not been reported
previously. Further analysis reveals that this reflection peak is attributed to
the orthorhombic (Pbam) phase, indicating the coexisting of monoclinic phase
with orthorhombic phase in low pressure range.


title: Gauge CPT as a Possible Alternative to the Dark Matter Hypothesis

abstract:
  A new force is proposed in order to explain galactic rotation curves. CPT is
chosen as the underlying symmetry of the new force because it is a universal
spacetime symmetry. Local CPT transformations are presented for the Dirac field
(matter) and the vierbein describing curved spacetime. A nonvanishing variation
of the Dirac action in curved spacetime is thus derived. Because the metric
spin connection of general relativity cannot accommodate the variation induced
by the local CPT symmetry, a new gauge field is introduced. The transformation
of the new field is derived which implies the new field is massless.
Experimental speculations based on the zero mass of the new gauge field are
presented. It is shown that one type of Yang-Mills Lagrangian density is not
invariant under local CPT transformations.


title: Linear and Parallel Learning of Markov Random Fields

abstract:
  We introduce a new embarrassingly parallel parameter learning algorithm for
Markov random fields with untied parameters which is efficient for a large
class of practical models. Our algorithm parallelizes naturally over cliques
and, for graphs of bounded degree, its complexity is linear in the number of
cliques. Unlike its competitors, our algorithm is fully parallel and for
log-linear models it is also data efficient, requiring only the local
sufficient statistics of the data to estimate parameters.


title: Can spontaneous symmetry breaking order develop in a topological phase?

abstract:
  Landau's symmetry breaking theory is the basis of modern condensed matter
physics, from which most phases can be understood. The recent discovery of
topological insulators simulates the study on the topological phase which is
beyond this theory. An interesting question is whether the topological phase
and spontaneous symmetry breaking order can coexist. We study this problem
based on the topological phase in the Haldane model. Firstly by including a
staggered potential, we show that if the system is subjected to the symmetry
needed by the charge density wave (CDW) order in advance, the topological phase
can coexist with the CDW order, realizing the topological CDW phase. While when
the nearest neighor interaction which preserves the symmetry of the origin
Hamiltonian is included, the CDW order can not develop from spontaneous
symmetry breaking in the topological phase. The results imply that a
spontaneous symmetry breaking order may not develop in a topological phase.


title: Testing Relativity with High-Energy Astrophysical Neutrinos

abstract:
  The recent observation of high-energy astrophysical neutrinos can be used to
constrain violations of Lorentz invariance emerging from a quantum theory of
gravity. We perform threshold and Cherenkov analyses that improve existing
bounds by factors ranging from about a million to 10^{20}.


title: Charged charmoniumlike state $Z_c(3900)^\pm$ via meson photoproduction

abstract:
  In this work, we explore the production of the newly observed charged
charmoniumlike state $Z_c(3900)^\pm$ by the photoproduction process $\gamma
p\to Z_c(3900)^+n$. Our numerical result indicates that the maximum of the
calculated total cross section of $\gamma p\to Z_c(3900)^+n$ can reach up to
the order of $0.1 \mu b$. Furthermore, the Dalitz plot analysis is performed by
considering the Pomeron exchange as the background contribution. This analysis
shows that the $Z_c(3900)^+$ signal can be distinguished from the background
easily and the best energy window of searching for $Z_c(3900)^+$ is
$\sqrt{s}\simeq7$ GeV, which is important information for further experimental
study of $Z_c(3900)^+$ by meson photoproduction.


title:
Mixing nonclassical pure states in a linear-optical network almost
  always generates modal entanglement

abstract:
  In quantum optics a pure state is considered classical, relative to the
statistics of photodetection, if and only if it is a coherent state. A
different and newer notion of nonclassicality is based on modal entanglement.
One example that relates these two notions is the Hong-Ou-Mandel effect, where
modal entanglement is generated by a beamsplitter from the nonclassical
photon-number state. This suggests that beamsplitters or, more generally,
linear-optical networks are mediators of the two notions of nonclassicality. In
this Brief Report, we show the following: Given a nonclassical
pure-product-state input to an N-port linear-optical network, the output is
almost always mode entangled; the only exception is a product of squeezed
states, all with the same squeezing strength, input to a network that does not
mix the squeezed and anti-squeezed quadratures. Our work thus gives a necessary
and sufficient condition for a linear network to generate modal entanglement
from pure product inputs, a result that is of immediate relevance to the boson
sampling problem.


title: Linear Symplectomorphisms as R-Lagrangian Subspaces

abstract:
  The graph of a real symplectic linear transformation is an R-Lagrangian
subspace of a complex symplectic vector space. The restriction of the complex
symplectic form is thus purely imaginary and may be expressed in terms of the
generating function of the transformation. We provide explicit formulas;
moreover, as an application, we give an explicit general formula for the
metaplectic representation of the real symplectic group.


title: The only regular inclines are distributive lattices

abstract:
  An incline is an additively idempotent semiring in which the product of two
elements is always less than or equal to either factor. This paper proves that
the only regular inclines are distributive lattices, which also implies that
there is no noncommutative regular incline.


title:
Spin-orbit coupling and spin Hall effect for neutral atoms without
  spin-flips

abstract:
  We propose a scheme which realizes spin-orbit coupling and the spin Hall
effect for neutral atoms in optical lattices without relying on near resonant
laser light to couple different spin states. The spin-orbit coupling is created
by modifying the motion of atoms in a spin-dependent way by laser recoil. The
spin selectivity is provided by Zeeman shifts created with a magnetic field
gradient. Alternatively, a quantum spin Hamiltonian can be created by
all-optical means using a period- tripling, spin-dependent superlattice.


title: Natural curvature for manifest T-duality

abstract:
  We reformulate the manifestly T-dual description of the massless sector of
the closed bosonic string, directly from the geometry associated with the (left
and right) affine Lie algebra of the coset space Poincare/Lorentz. This
construction initially doubles not only the (spacetime) coordinates for
translations but also those for Lorentz transformations (and their dual). As a
result, the Lorentz connection couples directly to the string (as does the
vielbein), rather than being introduced ad hoc to the covariant derivative as
previously. This not only reproduces the old definition of T-dual torsion, but
automatically gives a general, covariant definition of T-dual curvature (but
still with some undetermined connections).