title:
Critical current scaling in long diffusive graphene-based Josephson
  junctions

abstract:
  We present transport measurements on long diffusive graphene-based Josephson
junctions. Several junctions are made on a single-domain crystal of CVD
graphene and feature the same contact width of ~9$\mu$m but vary in length from
400 to 1000 nm. As the carrier density is tuned with the gate voltage, the
critical current in the these junctions spans a range from a few nA up to more
than $5\mu$A, while the Thouless energy, ETh, covers almost two orders of
magnitude. Over much of this range, the product of the critical current and the
normal resistance IcRn is found to scale linearly with ETh, as expected from
theory. However, the ratio IcRn /ETh is found to be 0.1-0.2: much smaller than
the predicted ~10 for long diffusive SNS junctions.


title: Generalization of the Force Approach to Radiation Reaction

abstract:
  A generalization of the force approach to radiation reaction is given, taken
into consideration an arbitrary motion of the charged particle . The expression
obtained brings about the expression already given for the linear an the
circular acceleration cases.


title: Unimodular f(T) gravity

abstract:
  We reconstruct the geometrical $f(T)$ actions in the framework of unimodular
$f(T)$ gravity. The unimodular $f(T)$ gravity yields stunning properties
related to the generalized Friedmann equations. Indeed, it has been found that
depending on the form of the Friedmann equations, the Lagrange multipliers may
or not depend on the time parameter $\tau$. Moreover we find that the
reconstruction of $f(T)$ functions can be easily performed in general, not
depending on a given scale factor, or can determine a particular way, depending
on a given scale factor, in the vacuum. It is noted that the reconstruction of
a general action joins is consistent to the unimodular gravity for the constant
$\Lambda$


title: Maximal Abelian gauge and a generalized BRST transformation

abstract:
  We apply a generalized Becchi-Rouet-Stora-Tyutin (BRST) formulation to
establish a connection between the gauge-fixed $SU(2)$ Yang-Mills (YM) theories
formulated in the Lorenz gauge and in the Maximal Abelian (MA) gauge. It is
shown that the generating functional corresponding to the Faddeev-Popov (FP)
effective action in the MA gauge can be obtained from that in the Lorenz gauge
by carrying out an appropriate finite and field-dependent BRST (FFBRST)
transformation. In this procedure, the FP effective action in the MA gauge is
found from that in the Lorenz gauge by incorporating the contribution of
non-trivial Jacobian due to the FFBRST transformation of the path integral
measure. The present FFBRST formulation might be useful to see how Abelian
dominance in the MA gauge is realized in the Lorenz gauge.


title: A screened automated structural search with semiempirical methods

abstract:
  We developed an interface program between a program suite for an automated
search of chemical reaction pathways, GRRM, and a program package of
semiempirical methods, MOPAC. A two-step structural search is proposed as an
application of this interface program. A screening test is first performed by
semiempirical calculations. Subsequently, a reoptimization procedure is done by
ab initio or density functional calculations. We apply this approach to ion
adsorption on cellulose. The computational efficiency is also shown for a GRRM
search. The interface program is suitable for the structural search of large
molecular systems for which semiempirical methods are applicable.


title: Fermionization in an Arbitrary Number of Dimensions

abstract:
  One purpose of this proceedings-contribution is to show that at least for
free massless particles it is possible to construct an explicit boson theory
which is exactly equivalent in terms of momenta and energy to a fermion theory.
The fermions come as $2^{d/2-1}$ families and the to this whole system of
fermions corresponding bosons come as a whole series of the Kalb-Ramond fields,
one set of components for each number of indexes on the tensor fields.
  Since Kalb-Ramond fields naturally (only) couple to the extended objects or
branes, we suspect that inclusion of interaction into such for a bosonization
prepared system - except for the lowest dimensions - without including branes
or something like that is not likely to be possible.
  The need for the families is easily seen just by using the theorem long ago
put forward by Aratyn and one of us (H.B.F.N.), which says that to have the
statistical mechanics of the fermion system and the boson system to match one
needs to have the number of the field components in the ratio
$\frac{2^{d-1}-1}{2^{d-1}}= \frac{\# bosons}{\# fermions}$, enforcing that the
number of fermion components must be a multiple of $2^{d-1}$, where $d$ is the
space-time dimension. This "explanation" of the number of dimension is
potentially useful for the explanation for the number of dimension put forward
by one of us (S.N.M.B.) since long in the spin-charge-family theory, and leads
like the latter to typically (a multiple of) $4$ families.
  And this is the second purpose for our work on the fermionization in an
arbitrary number of dimensions - namely to learn how "natural" is the inclusion
of the families in the way the spin-charge-family theory does.


title: Galileons, phantom fields, and the fate of the Universe

abstract:
  In this paper we study cosmological dynamics of phantom as well as
non-phantom fields with linear potential in presence of Galileon correction
$(\partial_\mu\phi \partial^\mu\phi) \Box \phi$. We show that the Big Crunch
singularity is delayed compared to the standard case; the delay crucially
depends upon the strength of Galileon correction. As for the phantom Galileon,
$\rho_{\phi}$ is shown to grow more slowly compared to the standard phantom
delaying the approach to singularity. In case, $V\sim \phi^n, n>4$, Big Rip is
also delayed, similar phenomenon is shown to take place for potentials steeper
than the exponential.


title:
Propeller effect in two brightest transient X-ray pulsars: 4U 0115+63
  and V 0332+53

abstract:
  We present the results of the monitoring programmes performed with the
Swift/XRT telescope and aimed specifically to detect an abrupt decrease of the
observed flux associated with a transition to the propeller regime in two well
known X-ray pulsars 4U 0115+63 and V 0332+53 during their giant outbursts in
2015. Such transitions were detected at the threshold luminosities of
$(1.4\pm0.4)\times10^{36}$ erg s$^{-1}$ and $(2.0\pm0.4)\times10^{36}$ erg
s$^{-1}$ for 4U 0115+63 and V 0332+53, respectively. Spectra of the sources are
shown to be significantly softer during the low state. In both sources, the
accretion at rates close to the aforementioned threshold values briefly resumes
during the periastron passage following the transition into propeller regime.
The strength of the dipole component of the magnetic field required to inhibit
the accretion agrees well with estimates based on the position of the cyclotron
lines in their spectra, thus excluding presence of a strong multipole component
of the magnetic field in the vicinity of the neutron star.


title: AstroBlend: An Astrophysical Visualization Package for Blender

abstract:
  The rapid growth in scale and complexity of both computational and
observational astrophysics over the past decade necessitates efficient and
intuitive methods for examining and visualizing large datasets. Here, I present
{\it AstroBlend}, an open-source Python library for use within the three
dimensional modeling software, {\it Blender}. While {\it Blender} has been a
popular open-source software among animators and visual effects artists, in
recent years it has also become a tool for visualizing astrophysical datasets.
{\it AstroBlend} combines the three dimensional capabilities of {\it Blender}
with the analysis tools of the widely used astrophysical toolset, {\it yt}, to
afford both computational and observational astrophysicists the ability to
simultaneously analyze their data and create informative and appealing
visualizations. The introduction of this package includes a description of
features, work flow, and various example visualizations. A website -
www.astroblend.com - has been developed which includes tutorials, and a gallery
of example images and movies, along with links to downloadable data, three
dimensional artistic models, and various other resources.


title: Transporting a single-spin qubit through a double quantum dot

abstract:
  Coherent spatial transport or shuttling of a single electron spin through
semiconductor nanostructures is an important ingredient in many spintronic and
quantum computing applications. In this work we analyze the possible errors in
solid-state quantum computation due to leakage in transporting a single-spin
qubit through a semiconductor double quantum dot. In particular, we consider
three possible sources of leakage errors associated with such transport: finite
ramping times, spin-dependent tunneling rates between quantum dots induced by
finite spin-orbit couplings, and the presence of multiple valley states. In
each case we present quantitative estimates of the leakage errors, and discuss
how they can be minimized. Moreover, we show that in order to minimize leakage
errors induced by spin-dependent tunnelings, it is necessary to apply pulses to
perform certain carefully designed spin rotations. We further develop a
formalism that allows one to systematically derive constraints on the pulse
shapes and present a few examples to highlight the advantage of such an
approach.


title:
Isotropic at the Break? 3D Kinematics of Milky Way Halo Stars in the
  Foreground of M31

abstract:
  We present the line-of-sight (LOS) velocities for 13 distant main sequence
Milky Way halo stars with published proper motions. The proper motions were
measured using long baseline (5-7 years) multi-epoch HST/ACS photometry, and
the LOS velocities were extracted from deep (5-6 hour integrations) Keck
II/DEIMOS spectra. We estimate the parameters of the velocity ellipsoid of the
stellar halo using a Markov chain Monte Carlo ensembler sampler method. The
velocity second moments in the directions of the Galactic $(l,b,$ LOS)
coordinate system are $\langle v^2_l \rangle^{1/2} = 138^{+43}_{-26}$ km/s,
$\langle v^2_b \rangle^{1/2} = 88^{+28}_{-17}$ km/s, and $\langle
v^2_{\rm{LOS}} \rangle^{1/2} = 91^{+27}_{-14}$ km/s. We use these ellipsoid
parameters to constrain the velocity anisotropy of the stellar halo. Ours is
the first measurement of the anisotropy parameter $\beta$ using 3D kinematics
outside of the solar neighborhood. We find $\beta=-0.3^{+0.4}_{-0.9}$,
consistent with isotropy and lower than solar neighborhood $\beta$ measurements
by 2$\sigma$ ($\beta_{SN} \sim 0.5-0.7$). We identify two stars in our sample
that are likely members of the known TriAnd substructure, and excluding these
objects from our sample increases our estimate of the anisotropy to
$\beta=0.1^{+0.4}_{-1.0}$, which is still lower than solar neighborhood
measurements by $1\sigma$. The potential decrease in $\beta$ with
Galactocentric radius is inconsistent with theoretical predictions, though
consistent with recent observational studies, and may indicate the presence of
large, shell-type structure (or structures) at $r \sim 25$ kpc. The methods
described in this paper will be applied to a much larger sample of stars with
3D kinematics observed through the ongoing HALO7D program.


title:
A fast ionised wind in a Star Forming-Quasar system at z~1.5 resolved
  through Adaptive Optics assisted near-infrared data

abstract:
  Outflows are invoked in co-evolutionary models to link the growth of SMBH and
galaxies through feedback phenomena, and from the analysis of both galaxies and
Active Galactic Nuclei (AGN) samples at z$\sim1-3$, it is becoming clear that
powerful winds are quite common in AGN hosts. High-resolution and high S/N
observations are needed in order to uncover the physical properties of the wind
through kinematics analysis. We exploited VIMOS, SINFONI and Subaru/IRCS
Adaptive Optics data to study the kinematics properties on the scale the host
galaxy of XID5395, a luminous, X-ray obscured Starburst/Quasar merging system
at z$\sim1.5$ detected in the XMM-COSMOS field, and associated with an extreme
[O II] emitter (EW$\sim200$ \AA). We mapped, for the first time, at high
resolution the kinematics of the [O III] and H$\alpha$ line complexes and
linked them with the [O II] emission. The high spatial resolution achieved
allowed us to resolve all the components of the SB-QSO system. Our analysis
with a resolution of few kpc reveals complexities and asymmetries in and around
the nucleus of XID5395. The velocity field measured via non parametric analysis
reveals different kinematic components, with maximum blueshifted and redshifted
velocities up to $\simeq1300$ km s$^{-1}$, not spatially coincident with the
nuclear core. These extreme values of the observed velocities and the spatial
location can be explained by the presence of fast moving material. We also
spectroscopically confirm the presence of a merging system at the same redshift
of the AGN host. We propose that EW as large as $>150$ \AA\ in X-ray selected
AGN may be an efficient criterion to isolate objects associated to the short,
transition phase of "feedback" in the AGN-galaxy co-evolutionary path, which
will subsequently evolve in an unobscured QSO, as suggested from the different
observational evidences we accumulated for XID5395.


title: Ultimate Capacity of a Linear Time-Invariant Bosonic Channel

abstract:
  We determine the ultimate classical information capacity of a linear
time-invariant bosonic channel with additive phase-insensitive Gaussian noise.
This channel can model fiber-optic communication at power levels below the
threshold for significant nonlinear effects. We provide a general
continuous-time result that gives the ultimate capacity for such a channel
operating in the quasimonochromatic regime under an average power constraint.
This ultimate capacity is compared with corresponding results for heterodyne
and homodyne detection over the same channel.


title:
Constraining the properties of transitional disks in Chamaeleon I with
  Herschel

abstract:
  Transitional disks are protoplanetary disks with opacity gaps/cavities in
their dust distribution, a feature that may be linked to planet formation. We
perform Bayesian modeling of the three transitional disks SZ Cha, CS Cha and
T25 including photometry from the Herschel Space Observatory to quantify the
improvements added by these new data. We find disk dust masses between 2x10^-5
and 4x10^-4 Msun, and gap radii in the range of 7-18 AU, with uncertainties of
~ one order of magnitude and ~ 4 AU, respectively. Our results show that adding
Herschel data can significantly improve these estimates with respect to
mid-infrared data alone, which have roughly twice as large uncertainties on
both disk mass and gap radius. We also find weak evidence for different density
profiles with respect to full disks. These results open exciting new
possibilities to study the distribution of disk masses for large samples of
disks.


title:
A public code for general relativistic, polarised radiative transfer
  around spinning black holes

abstract:
  Ray tracing radiative transfer is a powerful method for comparing theoretical
models of black hole accretion flows and jets with observations. We present a
public code, grtrans, for carrying out such calculations in the Kerr metric,
including the full treatment of polarised radiative transfer and parallel
transport along geodesics. The code is written in Fortran 90 and efficiently
parallelises with OpenMP, and the full code and several components have Python
interfaces. We describe several tests which are used for verifiying the code,
and we compare the results for polarised thin accretion disc and semi-analytic
jet problems with those from the literature as examples of its use. Along the
way, we provide accurate fitting functions for polarised synchrotron emission
and transfer coefficients from thermal and power law distribution functions,
and compare results from numerical integration and quadrature solutions of the
polarised radiative transfer equations. We also show that all transfer
coefficients can play an important role in predicted images and polarisation
maps of the Galactic center black hole, Sgr A*, at submillimetre wavelengths.


title: NuSTAR observations of water megamaser AGN

abstract:
  Aims. Study the connection between the masing disk and obscuring torus in
Seyfert 2 galaxies.
  Methods. We present a uniform X-ray spectral analysis of the high energy
properties of 14 nearby megamaser Active Galactic Nuclei observed by NuSTAR. We
use a simple analytical model to localize the maser disk and understand its
connection with the torus by combining NuSTAR spectral parameters with
available physical quantities from VLBI mapping.
  Results. Most of the sources analyzed are heavily obscured, showing a column
density in excess of $\sim 10^{23}$ cm$^{-2}$. In particular, $79\%$ are
Compton-thick ($N_{\rm H} > 1.5 \times 10^{24}$ cm$^{-2}$). Using column
densities measured by NuSTAR, with the assumption that the torus is the
extension of the maser disk, and further assuming a reasonable density profile,
the torus dimensions can be predicted. They are found to be consistent with
mid-IR interferometry parsec-scale observations of Circinus and NGC 1068. In
this picture, the maser disk is intimately connected to the inner part of the
torus. It is probably made of a large number of molecular clouds connecting the
torus and the outer part of the accretion disk, giving rise to a thin disk
rotating in most cases in Keplerian or sub-Keplerian motion. This toy model
explains the established close connection between water megamaser emission and
nuclear obscuration as a geometric effect.


title:
Doppler term in the galaxy two-point correlation function: wide-angle,
  velocity, Doppler lensing and cosmic acceleration effects

abstract:
  We study the parity-odd part (that we shall call Doppler term) of the linear
galaxy two-point correlation function that arises from wide-angle, velocity,
Doppler lensing and cosmic acceleration effects. As it is important at low
redshift and at large angular separations, the Doppler term is usually
neglected in the current generation of galaxy surveys. For future wide-angle
galaxy surveys such as Euclid, SPHEREx and SKA, however, we show that the
Doppler term must be included. The effect of these terms is dominated by the
magnification due to relativistic aberration effects and the slope of the
galaxy redshift distribution and it generally mimics the effect of the local
type primordial non-Gaussianity with the effective nonlinearity parameter
$f_{\rm NL}^{\rm eff}$ of a few, we show that this would affect forecasts on
measurements of $f_{\rm NL}$ at low-redshift. Our results show that a survey at
low redshift with large number density over a wide area of the sky could detect
the Doppler term with a signal-to-noise ratio of $\sim 1-20$, depending on
survey specifications.


title: Chemistry as a diagnostic of prestellar core geometry

abstract:
  We present a new method for assessing the intrinsic 3D shape of prestellar
cores from molecular column densities. We have employed hydrodynamic
simulations of contracting, isothermal cores considering three intrinsic
geometries: spherical, cylindrical/filamentary and disk-like. We have coupled
our hydrodynamic simulations with non-equilibrium chemistry. We find that a)
when cores are observed very elongated (i.e. for aspect ratios $\le$ 0.15) the
intrinsic 3D geometry can be probed by their 2D molecular emission maps, since
these exhibit significant qualitative morphological differences between
cylindrical and disk-like cores. Specifically, if a disk-like core is observed
as a filamentary object in dust emission, then it will be observed as two
parallel filaments in $\rm{N_2H^{+}}$; b) for cores with higher aspect ratios
(i.e. 0.15 $\sim$ 0.9) we define a metric $\Delta$ that quantifies whether a
molecular column density profile is centrally peaked, depressed or flat. We
have identified one molecule ($\rm{CN}$) for which $\Delta$ as a function of
the aspect ratio probes the 3D geometry of the core; and c) for cores with
almost circular projections (i.e. for aspect ratios $\sim$ 1), we have
identified three molecules ($\rm{OH}$, $\rm{CO}$ and $\rm{H_2CO}$) that can be
used to probe the intrinsic 3D shape by close inspection of their molecular
column density radial profiles. We alter the temperature and the cosmic-ray
ionization rate and demonstrate that our method is robust against the choice of
parameters.


title:
Discovery of Rubidium, Cadmium, and Germanium Emission Lines in the
  Near-Infrared Spectra of Planetary Nebulae

abstract:
  We identify [Rb IV] 1.5973 and [Cd IV] 1.7204 micron emission lines in
high-resolution (R=40,000) near-infrared spectra of the planetary nebulae (PNe)
NGC 7027 and IC 5117, obtained with the IGRINS spectrometer on the 2.7-m
telescope at McDonald Observatory. We also identify [Ge VI] 2.1930 $\mu$m in
NGC 7027. Alternate identifications for these features are ruled out based on
the absence of other multiplet members and/or transitions with the same upper
levels. Ge, Rb, and Cd can be enriched in PNe by s-process nucleosynthesis
during the asymptotic giant branch (AGB) stage of evolution. To determine ionic
abundances, we calculate [Rb IV] collision strengths and use approximations for
those of [Cd IV] and [Ge VI]. Our identification of [Rb IV] 1.5973 $\mu$m is
supported by the agreement between Rb3+/H+ abundances found from this line and
the 5759.55 A feature in NGC 7027. Elemental Rb, Cd, and Ge abundances are
derived with ionization corrections based on similarities in ionization
potential ranges between the detected ions and O and Ne ionization states. Our
analysis indicates abundances 2-4 times solar for Rb and Cd in both nebulae. Ge
is subsolar in NGC 7027, but its abundance is uncertain due to the large and
uncertain ionization correction. The general consistency of the measured
relative s-process enrichments with predictions from models appropriate for
these PNe (2.0-2.5 M_sun, [Fe/H]= -0.37) demonstrates the potential of using PN
compositions to test s-process nucleosynthesis models.


title: Forming disk galaxies in wet major mergers. I. Three fiducial examples

abstract:
  Using three fiducial Nbody+SPH simulations, we follow the merging of two disk
galaxies with a hot gaseous halo component each, and examine whether the merger
remnant can be a spiral galaxy. The stellar progenitor disks are destroyed by
violent relaxation during the merging and most of their stars form a classical
bulge, while the remaining form a thick disk and its bar. A new stellar disk
forms subsequently and gradually in the remnant from the gas accreted mainly
from the halo. It is vertically thin and well extended in its equatorial plane.
A bar starts forming before the disk is fully in place, contrary to what is
assumed in idealised simulations of isolated bar-forming galaxies. It has
morphological features such as ansae and boxy/peanut bulges. Stars of different
ages populate different parts of the box/peanut. A disky pseudobulge forms
also, so that by the end of the simulation, all three types of bulges coexist.
The oldest stars are found in the classical bulge, followed by those of the
thick disk, then by those in the thin disk. The youngest stars are in the
spiral arms and the disky pseudobulge. The disk surface density profiles are of
type II (exponential with downbending), and the circular velocity curves are
flat and show that the disks are submaximum in these examples: two clearly so
and one near-borderline between maximum and submaximum. On average, only
roughly between 10 and 20% of the stellar mass is in the classical bulge of the
final models, i.e. much less than in previous simulations.


title:
Bilayer Graphene as a platform for Bosonic Symmetry Protected
  Topological States

abstract:
  Bosonic symmetry protected topological (BSPT) states, the bosonic analogue of
topological insulators, have attracted enormous theoretical interest in the
last few years. Although BSPT states have been classified by various
approaches, there is so far no successful experimental realization of any BSPT
state in two or higher dimensions. In this paper, we propose that a two
dimensional BSPT state with $U(1) \times U(1)$ symmetry can be realized in
bilayer graphene in a magnetic field. Here the two $U(1)$ symmetries represent
total spin $S^z$ and total charge conservation respectively. The Coulomb
interaction plays a central role in this proposal -- it gaps out all the
fermions at the boundary, so that only bosonic charge and spin degrees of
freedom are gapless and protected at the edge. Based on the bosonic nature of
the boundary states, we derive the bulk wave function for the bosonic charge
and spin degrees of freedom, which takes exactly the same form as the desired
BSPT state. We also propose that the bulk quantum phase transition between the
BSPT and trivial phase, could become a "bosonic phase transition" with
interactions. That is, only bosonic modes close their gap at the transition,
which is fundamentally different from all the well-known topological insulator
to trivial insulator transitions which occur for free fermion systems. We
discuss various experimental consequences of this proposal.


title: Small neutrino masses from gravitational $\theta$-term

abstract:
  We present how a neutrino condensate and small neutrino masses emerge from a
topological formulation of gravitational anomaly. We first recapitulate how a
gravitational $\theta$-term leads to the emergence of a new bound neutrino
state analogous to the $\eta'$ meson of QCD. Then we show the consequent
formation of a neutrino vacuum condensate, which effectively generates small
neutrino masses. Afterwards we outline several phenomenological consequences of
our neutrino mass generation model. The cosmological neutrino mass bound
vanishes since we predict the neutrinos to be massless until the phase
transition in the late Universe, $T\sim {\rm meV}$. Deviations from an equal
flavor rate due to enhanced neutrino decays in extraterrestrial neutrino fluxes
can be observed in future IceCube data. The current cosmological neutrino
background only consists of the lightest neutrinos, which, due to enhanced
neutrino-neutrino interactions, either bind up, form a superfluid, or
completely annihilate into massless bosons. Strongly coupled relic neutrinos
could provide a contribution to cold dark matter in the late Universe, together
with the new proposed particles and topological defects, which may have formed
during neutrino condensation. These enhanced interactions could also be a
source of relic neutrino clustering in our Galaxy, which possibly makes the
overdense cosmic neutrino background detectable in the KATRIN experiment. The
neutrino condensate provides a mass for the hypothetical $B-L$ gauge boson,
leading to a gravity-competing force detectable in short-distance measurements.
Gravitational waves detections have the potential to probe our neutrino mass
generation mechanism.


title: Fundamental Constants as Monitors of the Universe

abstract:
  Astronomical observations have a unique ability to determine the laws of
physics at distant times in the universe. They, therefore, have particular
relevance in answering the basic question as to whether the laws of physics are
invariant with time. The dimesionless fundamental constants, such as the proton
to electron mass ratio and the fine structure constant are key elements in the
investigation. If they vary with time then the answer is clearly that the laws
of physics are not invariant with time and significant new physics must be
developed to describe the universe. Limits on their variance, on the other
hand, constrains the parameter space available to new physics that requires a
variation with time of basic physical law. There are now observational
constraints on the time variation of the proton to electron mass ratio mu at
the 1.E-7 level. Constraints on the variation of the fine structure constant
alpha are less rigorous, 1E-5, but are imposed at higher redshift. The
implications of these limits on new cosmologies that require rolling scalar
fields has already had its first investigations. Here we address the
implications on basic particle physics. The proton to electron mass ratio is
obviously dependent on the particle physics parameters that set the mass of the
proton and the electron. To first order the ratio is dependent on a combination
of the Quantum Chromodynamic scale, the Yukawa couplings, and the Higgs Vacuum
Expectation Value. Here that relationship is quantitative defined for the first
time. When coupled with previous determinations of the relation of the fine
structure constant to the same parameters two constraints exist on the
fractional variation of these parameters with time. A third independent
constraint involving only the three parameters could set the stage for
constraints on their individual fractional variation.


title: Transport equation with integral terms

abstract:
  We prove some theorems on the existence, uniqueness, stability and
compactness properties of solutions to inhomogeneous transport equations with
Sobolev coefficients, where the inhomogeneous term depends upon the solution
through an integral operator. Contrary to the usual DiPerna-Lions approach, the
essential step is to formulate the problem in the Lagrangian setting. Some
motivations to study the above problem arise from the description of polymeric
flows, where such kind of equations are coupled with other Navier-Stokes type
equations. Using the results for the transport equation we will provide, in a
separate paper, a sequential stability theorem for the full problem of the flow
of concentrated polymers.


title:
Spontaneous finite momentum pairing in superconductors without inversion
  symmetry

abstract:
  We analyze the effect of magnetic fluctuations in superconductors with strong
spin-orbit coupling and show that they drive a phase transition between two
superconducting states: a conventional phase with zero center-of-mass momentum
of Cooper pairs, and an exotic phase with non-zero pair momentum. The latter is
found to exhibit persistent currents without magnetic field in doubly connected
geometries such as rings. Surprisingly, the transition temperature into the
superconducting state can be increased by applying a Zeeman magnetic field.


title:
Pulsating low-mass white dwarfs in the frame of new evolutionary
  sequences: III. The pre-ELM white dwarf instability strip

abstract:
  Two low-mass pre-white dwarfs, which could be precursors of ELM white dwarfs,
have been observed to show multiperiodic photometric variations. They could
constitute a new class of pulsating low-mass pre-white dwarf stars. We present
a detailed nonadiabatic pulsation study of such stars, employing full
evolutionary sequences of low-mass He-core pre-white dwarf models. We have
considered models in which element diffusion is accounted for and also models
in which it is neglected. We confirm and explore in detail a new instability
strip in the domain of low gravities and low effective temperatures of the
$T_{\rm eff}-\log g$ diagram, where low-mass pre-white dwarfs are currently
found. The destabilized modes are radial and nonradial $p$ and $g$ modes
excited by the $\kappa-\gamma$ mechanism acting mainly at the zone of the
second partial ionization of He, with non-negligible contributions from the
region of the first partial ionization of He and the partial ionization of H.
The computations with element diffusion are unable to explain the pulsations
observed in the two known pulsating pre-white dwarfs, suggesting that element
diffusion might be inhibited at these stages of the pre-white dwarf evolution.
Our nonadiabatic models without diffusion, on the other hand, naturally explain
the existence and range of periods of the pulsating pre-white dwarf star WASP
J1628$+$10B, although they fail to explain the pulsations of WASP J0247$-$25B,
the other known member of the class, indicating that the He abundance in the
driving region of this star might be substantially larger than predicted by our
models. Further discoveries of additional members of this new class of
pulsating stars and their analysis in the context of the theoretical background
presented in this paper will shed new light on the evolutionary history of
their progenitor stars.


title: Bifurcations of limit cycles of perturbed completely integrable systems

abstract:
  The main purpose of this article is to study from the geometric point of view
the problem of limit cycles bifurcation of perturbed completely integrable
systems.


title: Structure theorems for singular minimal laminations

abstract:
  We apply the local removable singularity theorem for minimal laminations and
the local picture theorem on the scale of topology to obtain two descriptive
results for certain possibly singular minimal laminations of $\mathbb{R}^3$.
These two global structure theorems will be applied in forthcoming papers to
obtain bounds on the index and the number of ends of complete, embedded minimal
surfaces of fixed genus and finite topology in $\mathbb{R}^3$, and to prove
that a complete, embedded minimal surface in $\mathbb{R}^3$ with finite genus
and a countable number of ends is proper.


title:
Harmonic-Number Summation Identities, Symmetric Functions, and Multiple
  Zeta Values

abstract:
  We show how infinite series of a certain type involving generalized harmonic
numbers can be computed using a knowledge of symmetric functions and multiple
zeta values. In particular, we prove and generalize some identities recently
conjectured by J. Choi, and give several more families of identities of a
similar nature.


title:
On the Instability of Sensor Orientation in Gait Verification on Mobile
  Phone

abstract:
  Authentication schemes using tokens or biometric modalities have been
proposed to ameliorate the security strength on mobile devices. However, the
existing approaches are obtrusive since the user is required to perform
explicit gestures in order to be authenticated. While the gait signal captured
by inertial sensors is understood to be a reliable profile for effective
implicit authentication, recent studies have been conducted in ideal conditions
and might therefore be inapplicable in the real mobile context. Particularly,
the acquiring sensor is always fixed to a specific position and orientation.
This paper mainly focuses on addressing the instability of sensor's orientation
which mostly happens in the reality. A flexible solution taking advantages of
available sensors on mobile devices which can help to handle this problem is
presented. Moreover, a novel gait recognition method utilizes statistical
analysis and supervised learning to adapt itself to the instability of the
biometric gait under various circumstances is also proposed. By adopting
PCA+SVM to construct the gait model, the proposed method outperformed other
state-of-the-art studies, with an equal error rate of 2.45\% and accuracy rate
of 99.14\% in terms of the verification and identification aspects being
achieved, respectively.


title: Optimizing Real-Time Vaccine Allocation in a Stochastic SIR Model

abstract:
  Real-time vaccination following an outbreak can effectively mitigate the
damage caused by an infectious disease. However, in many cases, available
resources are insufficient to vaccinate the entire at-risk population,
logistics result in delayed vaccine deployment, and the interaction between
members of different cities facilitates a wide spatial spread of infection.
Limited vaccine, time delays, and interaction (or coupling) of cities lead to
tradeoffs that impact the overall magnitude of the epidemic. These tradeoffs
mandate investigation of optimal strategies that minimize the severity of the
epidemic by prioritizing allocation of vaccine to specific subpopulations. We
use an SIR model to describe the disease dynamics of an epidemic which breaks
out in one city and spreads to another. We solve a master equation to determine
the resulting probability distribution of the final epidemic size. We then
identify tradeoffs between vaccine, time delay, and coupling, and we determine
the optimal vaccination protocols resulting from these tradeoffs.


title:
Discovery of ultra-steep spectrum giant radio galaxy with recurrent
  radio jet activity in Abell 449

abstract:
  We report a discovery of a 1.3 Mpc diffuse radio source with extremely steep
spectrum fading radio structures in the vicinity of the Abell 449 cluster of
galaxies. Its extended diffuse lobes are bright only at low radio frequencies
and their synchrotron age is about 160 Myr. The parent galaxy of the extended
relic structure, which is the dominant galaxy within the cluster, is starting a
new jet activity. There are three weak X-rays sources in the vicinity of the
cluster as found in the ROSAT survey, however it is not known if they are
connected with this cluster of galaxies. Just a few radio galaxy relics are
currently known in the literature, as finding them requires sensitive and high
angular resolution low-frequency radio observations. Objects of this kind,
which also are starting a new jet activity, are important for understanding the
life cycle and evolution of active galactic nuclei. A new 613 MHz map as well
as the archival radio data pertaining to this object are presented and
analyzed.


title:
Market Model and Optimal Pricing Scheme of Big Data and Internet of
  Things (IoT)

abstract:
  Big data has been emerging as a new approach in utilizing large datasets to
optimize complex system operations. Big data is fueled with Internet-of-Things
(IoT) services that generate immense sensory data from numerous sensors and
devices. While most current research focus of big data is on machine learning
and resource management design, the economic modeling and analysis have been
largely overlooked. This paper thus investigates the big data market model and
optimal pricing scheme. We first study the utility of data from the data
science perspective, i.e., using the machine learning methods. We then
introduce the market model and develop an optimal pricing scheme afterward. The
case study shows clearly the suitability of the proposed data utility
functions. The numerical examples demonstrate that big data and IoT service
provider can achieve the maximum profit through the proposed market model.


title: Time Resource Networks

abstract:
  The problem of scheduling under resource constraints is widely applicable.
One prominent example is power management, in which we have a limited
continuous supply of power but must schedule a number of power-consuming tasks.
Such problems feature tightly coupled continuous resource constraints and
continuous temporal constraints.
  We address such problems by introducing the Time Resource Network (TRN), an
encoding for resource-constrained scheduling problems. The definition allows
temporal specifications using a general family of representations derived from
the Simple Temporal network, including the Simple Temporal Network with
Uncertainty, and the probabilistic Simple Temporal Network (Fang et al.
(2014)).
  We propose two algorithms for determining the consistency of a TRN: one based
on Mixed Integer Programing and the other one based on Constraint Programming,
which we evaluate on scheduling problems with Simple Temporal Constraints and
Probabilistic Temporal Constraints.


title: Identifying False Alarms in the Kepler Planet Candidate Catalog

abstract:
  We present a new automated method to identify instrumental features
masquerading as small, long period planets in the \kepler\ planet candidate
catalog. These systematics, mistakenly identified as planet transits, can have
a strong impact on occurrence rate calculations because they cluster in a
region of parameter space where Kepler's sensitivity to planets is poor. We
compare individual transit-like events to a variety of models of real transits
and systematic events, and use a Bayesian Information Criterion to evaluate the
likelihood that each event is real. We describe our technique and test its
performance on simulated data. Results from this technique are incorporated in
the \kepler\ Q1-17 DR24 planet candidate catalog of \citet{Coughlin15}.


title: Image encryption with dynamic chaotic Look-Up Table

abstract:
  In this paper we propose a novel image encryption scheme. The proposed method
is based on the chaos theory. Our cryptosystem uses the chaos theory to define
a dynamic chaotic Look-Up Table (LUT) to compute the new value of the current
pixel to cipher. Applying this process on each pixel of the plain image, we
generate the encrypted image. The results of different experimental tests, such
as Key space analysis, Information Entropy and Histogram analysis, show that
the proposed encryption image scheme seems to be protected against various
attacks. A comparison between the plain and encrypted image, in terms of
correlation coefficient, proves that the plain image is very different from the
encrypted one.


title: Design of false color palettes for grayscale reproduction

abstract:
  Design of false color palette is quite easy but some effort has to be done to
achieve good dynamic range, contrast and overall appearance of the palette.
Such palettes, for instance, are commonly used in scientific papers for
presenting the data. However, to lower the cost of the paper most scientists
decide to let the data to be printed in grayscale. The same applies to e-book
readers based on e-ink where most of them are still grayscale. For majority of
false color palettes reproducing them in grayscale results in ambiguous mapping
of the colors and may be misleading for the reader. In this article design of
false color palettes suitable for grayscale reproduction is described. Due to
the monotonic change of luminance of these palettes grayscale representation is
very similar to the data directly presented with a grayscale palette. Some
suggestions and examples how to design such palettes are provided.


title:
A Fast Eddy-current Non Destructive Testing Finite Element Solver in
  Steam Generator

abstract:
  In this paper we present an advanced numerical method to simulate a real life
challenging industrial problem that consists of the non-destructive testing in
steam generators. We develop a finite element technique that handles the big
data numerical set of systems arising when a discretization of the eddy-current
equation in three dimensional space is made. Using a high performance
technique, our method becomes fully efficient. We provide numerical simulations
using the software Freefem++ which has a powerful tool to handle finite element
method and parallel computing. We show that our technique speeds up the
simulation with a good efficiency factor.


title:
Optimal asymptotic bounds on the oracle use in computations from
  Chaitin's Omega

abstract:
  Chaitin's number Omega is the halting probability of a universal prefix-free
machine, and although it depends on the underlying enumeration of prefix-free
machines, it is always Turing-complete. It can be observed, in fact, that for
every computably enumerable (c.e.) real, there exists a Turing functional via
which Omega computes it, and such that the number of bits of omega that are
needed for the computation of the first n bits of the given number (i.e. the
use on argument n) is bounded above by a computable function h(n) = n+o(n). We
characterise the asymptotic upper bounds on the use of Chaitin's omega in
oracle computations of halting probabilities (i.e. c.e. reals). We show that
the following two conditions are equivalent for any computable function h such
that h(n)-n is non-decreasing: (1) h(n)-n is an information content measure,
(2) for every c.e. real there exists a Turing functional via which omega
computes the real with use bounded by h. We also give a similar
characterisation with respect to computations of c.e. sets from Omega, by
showing that the following are equivalent for any computable non-decreasing
function g: (1) g is an information-content measure, (2) for every c.e. set A,
Omega computes A with use bounded by g. Further results and some connections
with Solovay functions are given.


title: The quandary of quandles: The Borel completeness of a knot invariant

abstract:
  The isomorphism type of the knot quandle introduced by Joyce is a complete
invariant of tame knots. Whether two quandles are isomorphic is in practice
difficult to determine; we show that this question is provably hard:
isomorphism of quandles is Borel complete. The class of tame knots, however, is
trivial from the perspective of Borel reducibility, suggesting that equivalence
of tame knots may be reducible to a more tractable isomorphism problem.


title: The Faddeev Model and Scaling in Quantum Chromodynamics

abstract:
  The Faddeev two body bound state model is discussed as an example of a QCD
inspired model thought by some to exhibit dimensional transmutation. This
simple model is solved exactly and the growth of a specified dimensional energy
scale is shown to be an illusion.


title:
Isotope Effect on Electron-Phonon Interaction in Multiband
  Superconductor MgB2

abstract:
  We investigate the effect of isotope substitution on the electron-phonon
interaction in the multi-band superconductor MgB2 using tunable laser based
Angle Resolved Photoemission Spectroscopy. The kink structure around 70 meV in
the $\sigma$ band, which is caused by electron coupling to the E2g phonon mode,
is shifted to higher binding energy by ~3.5 meV in Mg(10)B2 and the shift is
not affected by superconducting transition. These results serve as the
benchmark for investigations of isotope effects in known, unconventional
superconductors and newly discovered superconductors where the origin of
pairing is unknown.


title:
Bohr's correspondence principle in quantum field theory and classical
  renormalization scheme: the Nelson model

abstract:
  In the mid Sixties Edward Nelson proved the existence of a consistent quantum
field theory that describes the Yukawa-like interaction of a non-relativistic
nucleon field with a relativistic meson field. Since then it is thought,
despite the renormalization procedure involved in the construction, that the
quantum dynamics should be governed in the classical limit by a
Schr\"odinger-Klein-Gordon system with Yukawa coupling. In the present paper we
prove this fact in the form of a Bohr correspondence principle. Besides, our
result enlighten the nature of the renormalization method employed in this
model which we interpret as a strategy that allows to put the related classical
Hamiltonian PDE in a normal form suitable for a canonical quantization.


title:
Morphological Transitions in Nanoscale Patterns Produced by Concurrent
  Ion Sputtering and Impurity Co-deposition

abstract:
  We modify the theory of nanoscale patterns produced by ion bombardment with
concurrent impurity deposition to take into account the effect that the
near-surface impurities have on the collision cascades. As the impurity
concentration is increased, the resulting theory successively yields a flat
surface, a rippled surface with its wavevector along the projected direction of
ion incidence, and a rippled surface with its wavevector rotated by 90 degrees.
Exactly the same morphological transitions were observed in recent experiments
in which silicon was bombarded with an argon ion beam and gold was co-deposited
[B.~Moon et al. arXiv:1601.02534 (2016)].


title: Modeling the Effects of Multiple Myeloma on Kidney Function

abstract:
  Multiple myeloma (MM), a plasma cell cancer, is associated with many health
challenges, including damage to the kidney by tubulointerstitial fibrosis. We
develop a mathematical model which captures the qualitative behavior of the
cell and protein populations involved. Specifically, we model the interaction
between cells in the proximal tubule of the kidney, free light chains, renal
fibroblasts, and myeloma cells. We analyze the model for steady-state solutions
to find a mathematically and biologically relevant stable steady-state
solution. This foundational model provides a representation of dynamics between
key populations in tubulointerstitial fibrosis that demonstrates how these
populations interact to affect patient prognosis in patients with MM and renal
impairment.


title: Effect of topological defects on "nuclear pasta" observables

abstract:
  [Background] The "pasta" phase of nuclear matter may play an important role
in the structure and evolution of neutron stars. Recent works suggest nuclear
pasta has a high resistivity which could be explained by the presence of long
lived topological defects. The defects act as impurities that decrease thermal
and electrical conductivity of the pasta. [Purpose] To quantify how topological
defects affect transport properties of nuclear pasta and estimate this effect
using an impurity parameter $Q_{\text{imp}}$. [Methods] Contrast molecular
dynamics simulations of up to 409\,600 nucleons arranged in parallel nuclear
pasta slabs (perfect pasta) with simulations of pasta slabs connected by
topological defects (impure pasta). From these simulations compare the
viscosity and heat conductivity of perfect and impure pasta to obtain an
effective impurity parameter $Q_{\text{imp}}$ due to the presence of defects.
[Results] Both the viscosity and thermal conductivity calculated for both
perfect and impure pasta are anisotropic, peaking along directions
perpendicular to the slabs and reaching a minimum close to zero parallel to
them. In our 409\,600 nucleon simulation topological defects connecting slabs
of pasta reduce both the thermal conductivity and viscosity on average by about
37\%. We estimate an effective impurity parameter due to the defects of order
$Q_{\text{imp}}\sim30$. [Conclusions] Topological defects in the pasta phase of
nuclear matter have an effect similar to impurities in a crystal lattice. The
irregularities introduced by the defects reduce the thermal and electrical
conductivities and the viscosity of the system. This effect can be
parameterized by a large impurity parameter $Q_{\text{imp}}\sim30$.


title: WIMP detection and slow ion dynamics in carbon nanotube arrays

abstract:
  Large arrays of aligned carbon nanotubes (CNTs), open at one end, could be
used as target material for the directional detection of weakly interacting
dark matter particles (WIMPs). As a result of a WIMP elastic scattering on a
CNT, a carbon ion might be injected in the body of the array and propagate
through multiple collisions within the lattice. The ion may eventually emerge
from the surface with open end CNTs, provided that its longitudinal momentum is
large enough to compensate energy losses and its transverse momentum approaches
the channeling conditions in a single CNT. Therefore, the angle formed between
the WIMP wind apparent orientation and the direction of parallel carbon
nanotube axes must be properly chosen. We focus on very low ion recoil kinetic
energies, related to low mass WIMPs (~ 10 GeV) where most of the existing
experiments have low sensitivity. Relying on some exact results on
two-dimensional lattices of circular obstacles, we study the low energy ion
motion in the transverse plane with respect to CNT directions. New constraints
are obtained on how to devise the CNT arrays to maximize the detection
efficiency.


title:
Topological magnon bound-states in periodically modulated Heisenberg XXZ
  chains

abstract:
  Strongly interacting topological states in multi-particle quantum systems
pose great challenges to both theory and experiment. Recently, bound states of
elementary spin waves (magnons) in quantum magnets have been experimentally
observed in quantum Heisenberg chains comprising ultracold Bose atoms in
optical lattices. Here, we explore a strongly interacting topological state
called topological magnon bound-state in the quantum Heisenberg chain under
cotranslational symmetry. We find that the cotranslational symmetry is the key
to the definition of a topological invariant for multi-particle quantum states,
which enables us to characterize the topological features of multi-magnon
excitations. We calculate energy spectra, density distributions, correlations
and Chern numbers of the two-magnon bound-states and show the existence of
topological protected edge bound-states. Our study not only opens a new
prospect to pursue topological magnon bound-states, but also gives insights
into the characterization and understanding of strongly interacting topological
states.


title: Learning Efficient Algorithms with Hierarchical Attentive Memory

abstract:
  In this paper, we propose and investigate a novel memory architecture for
neural networks called Hierarchical Attentive Memory (HAM). It is based on a
binary tree with leaves corresponding to memory cells. This allows HAM to
perform memory access in O(log n) complexity, which is a significant
improvement over the standard attention mechanism that requires O(n)
operations, where n is the size of the memory.
  We show that an LSTM network augmented with HAM can learn algorithms for
problems like merging, sorting or binary searching from pure input-output
examples. In particular, it learns to sort n numbers in time O(n log n) and
generalizes well to input sequences much longer than the ones seen during the
training. We also show that HAM can be trained to act like classic data
structures: a stack, a FIFO queue and a priority queue.


title:
Dynamics of cholesteric liquid crystals in the presence of random
  magnetic fields

abstract:
  Based on dynamic renormalization group techniques, this letter analyzes the
effects of external stochastic perturbations on the dynamical properties of
cholesteric liquid crystals, studied in presence of a random magnetic field.
Our analysis quantifies the nature of the temperature dependence of the
dynamics; the results also highlight a hitherto unexplored regime in
cholesteric liquid crystal dynamics. We show that stochastic fluctuations drive
the system to a second-ordered Kosterlitz-Thouless phase transition point,
eventually leading to a Kardar-Parisi-Zhang (KPZ) universality class. The
results go beyond quasi-first order mean-field theories, and provides the first
theoretical understanding of a KPZ phase in distorted nematic liquid crystal
dynamics.


title: Discriminative Regularization for Generative Models

abstract:
  We explore the question of whether the representations learned by classifiers
can be used to enhance the quality of generative models. Our conjecture is that
labels correspond to characteristics of natural data which are most salient to
humans: identity in faces, objects in images, and utterances in speech. We
propose to take advantage of this by using the representations from
discriminative classifiers to augment the objective function corresponding to a
generative model. In particular we enhance the objective function of the
variational autoencoder, a popular generative model, with a discriminative
regularization term. We show that enhancing the objective function in this way
leads to samples that are clearer and have higher visual quality than the
samples from the standard variational autoencoders.


title: On Waring's problem for intermediate powers

abstract:
  Let $G(k)$ denote the least number $s$ such that every sufficiently large
natural number is the sum of at most $s$ positive integral $k$th powers. We
show that $G(7)\le 31$, $G(8)\le 39$, $G(9)\le 47$, $G(10)\le 55$, $G(11)\le
63$, $G(12)\le 72$, $G(13)\le 81$, $G(14)\le 90$, $G(15)\le 99$, $G(16)\le
108$.


title: Metamaterial control of stimulated Brillouin scattering

abstract:
  Using full opto-acoustic numerical simulations, we demonstrate enhancement
and suppression of the SBS gain in a metamaterial comprising a subwavelength
cubic array of dielectric spheres suspended in a dielectric background
material. We develop a general theoretical framework and present several
numerical examples using technologically important materials. For As$_2$S$_3$
spheres in silicon, we achieve a gain enhancement of more than an order of
magnitude compared to pure silicon, and for GaAs spheres in silicon, full
suppression is obtained. The gain for As$_2$S$_3$ glass can also be strongly
suppressed by embedding silica spheres. The constituent terms of the gain
coefficient are shown to depend in a complex way on the filling fraction. We
find that electrostriction is the dominant effect behind the control of SBS in
bulk media.


title:
$SU(1,1)$ Approach to Stokes Parameters and the Theory of Light
  Polarization

abstract:
  We introduce an alternative approach to the polarization theory of light.
This is based on a set of quantum operators, constructed from two independent
bosons, being three of them the $su(1,1)$ Lie algebra generators, and the other
one, the Casimir operator of this algebra. By taking the expectation value of
these generators in a two-mode coherent state, their classical limit is
obtained. We use these classical quantities to define the new Stokes-like
parameters. We show that the light polarization ellipse can be written in terms
of the Stokes-like parameters. Also, we write these parameters in terms of
other two quantities, and show that they define a one-sheet (Poincar\'e
hyperboloid) of a two-sheet hyperboloid. Our study is restricted to the case of
a monochromatic plane electromagnetic wave which propagates along the $z$ axis.

categories: quant-ph hep-th math-ph math.MP physics.optics


title: Adically Finite Chain Complexes

abstract:
  We investigate the similarities between adic finiteness and homological
finiteness for chain complexes over a commutative noetherian ring. In
particular, we extend the isomorphism properties of certain natural morphisms
from homologically finite complexes to adically finite complexes. We do the
same for characterizations of certain homological dimensions. In addition, we
study transfer of adic finiteness along ring homomorphisms, all with a view
toward subsequent applications.


title: Adic Finiteness: Bounding Homology and Applications

abstract:
  We prove a versions of amplitude inequalities of Iversen, Foxby and Iyengar,
and Frankild and Sather-Wagstaff that replace finite generation conditions with
adic finiteness conditions. As an application, we prove that a local ring $R$
of prime characteristic is regular if and only if for some proper ideal
$\mathfrak b$ the derived local cohomology complex
$\mathbf{R}\Gamma_{\mathfrak{b}}(R)$ has finite flat dimension when viewed
through some positive power of the Frobenius endomorphism.


title: Extended Local Cohomology and Local Homology

abstract:
  We present an in-depth exploration of the module structures of local
(co)homology modules (moreover, for complexes) over the completion $\widehat
R^{\mathfrak a}$ of a commutative noetherian ring $R$ with respect to a proper
ideal $\mathfrak a$. In particular, we extend Greenlees-May Duality and MGM
Equivalence to track behavior over $\widehat R^{\mathfrak a}$, not just over
$R$. We apply this to the study of two recent versions of homological
finiteness for complexes, and to certain isomorphisms, with a view toward
further applications. We also discuss subtleties and simplifications in the
computations of these functors.


title: Adic Foxby Classes

abstract:
  We continue our work on adic semidualizing complexes over a commutative
noetherian ring $R$ by investigating the associated Auslander and Bass classes
(collectively known as Foxby classes), following Foxby and Christensen.
Fundamental properties of these classes include Foxby Equivalence, which
provides an equivalence between the Auslander and Bass classes associated to a
given adic semidualizing complex. We prove a variety of stability results for
these classes, for instance, with respect to $F\otimes^{\mathbf{L}}_R-$ where
$F$ is an $R$-complex finite flat dimension, including special converses of
these results. We also investigate change of rings and local-global properties
of these classes.


title:
Busy Beaver Machines and the Observant Otter Heuristic (or How to Tame
  Dreadful Dragons)

abstract:
  The busy beaver is a well-known specific example of a non-computable
function. Whilst many aspect of this problem have been investigated, it is not
always easy to find thorough and convincing evidence for the claims made about
the maximality of particular machines, and the phenomenal size of some of the
numbers involved means that it is not obvious that the problem can be feasibly
addressed at all. In this paper we address both of these issues. We discuss a
framework in which the busy beaver problem and similar problems may be
addressed, and the appropriate processes for providing evidence of claims made.
We also show how a simple heuristic, which we call the observant otter, can be
used to evaluate machines with an extremely large number of execution steps
required to terminate. We also show empirical results for an implementation of
this heuristic which show how this heuristic is effective for all known
`monster' machines.


title: On subgroup conjugacy separability of hyperbolic QVH-groups

abstract:
  A group $G$ is called subgroup conjugacy separable (abbreviated as SCS) if
any two finitely generated and non-conjugate subgroups of $G$ remain
non-conjugate in some finite quotient of $G$. An into-conjugacy version of SCS
is abbreviated by SICS. We prove that if $G$ is a hyperbolic group, $H_1$ is a
quasiconvex subgroup of $G$, and $H_2$ is a subgroup of $G$ which is
elementwise conjugate into $H_1$, then there exists a finite index subgroup of
$H_2$ which is conjugate into $H_1$. As corollary, we deduce that fundamental
groups of closed hyperbolic 3-manifolds and torsion-free small cancellation
groups with finite $C'(1/6)$ or $C'(1/4)-T(4)$ presentations are hereditarily
quasiconvex-SCS and hereditarily quasiconvex-SICS, and that surface groups are
SCS and SICS. We also show that the word "quasiconvex" cannot be deleted for at
least small cancellation groups.


title:
Sharp bounds for ordinary and signless Laplacian spectral radii of
  uniform hypergraphs

abstract:
  We give sharp upper bounds for the ordinary spectral radius and signless
Laplacian spectral radius of a uniform hypergraph in terms of the average
$2$-degrees or degrees of vertices, respectively, and we also give a lower
bound for the ordinary spectral radius. We also compare these bounds with known
ones.


title: On Christoffel and standard words and their derivatives

abstract:
  We introduce and study natural derivatives for Christoffel and finite
standard words, as well as for characteristic Sturmian words. These
derivatives, which are realized as inverse images under suitable morphisms,
preserve the aforementioned classes of words. In the case of Christoffel words,
the morphisms involved map $a$ to $a^{k+1}b$ (resp.,~$ab^{k}$) and $b$ to
$a^{k}b$ (resp.,~$ab^{k+1}$) for a suitable $k>0$. As long as derivatives are
longer than one letter, higher-order derivatives are naturally obtained. We
define the depth of a Christoffel or standard word as the smallest order for
which the derivative is a single letter. We give several combinatorial and
arithmetic descriptions of the depth, and (tight) lower and upper bounds for
it.


title:
Tunable plasmonic reflection by bound 1D electron states in a 2D Dirac
  metal

abstract:
  We show that surface plasmons of a two-dimensional Dirac metal such as
graphene can be reflected by line-like perturbations hosting one-dimensional
electron states. The reflection originates from a strong enhancement of the
local optical conductivity caused by optical transitions involving these bound
states. We propose that the bound states can be systematically created,
controlled, and liquidated by an ultranarrow electrostatic gate. Using infrared
nanoimaging, we obtain experimental evidence for the locally enhanced
conductivity of graphene induced by a carbon nanotube gate, which supports this
theoretical concept.


title: Squeezing quadrature rotation in the acoustic band via optomechanics

abstract:
  We examine the use of optomechanically-generated squeezing to obtain a
sensitivity enhancement for interferometers in the gravitational-wave band. The
intrinsic dispersion characteristics of optomechanical squeezing around the
mechanical frequency are able to produce squeezing at different quadratures
over the spectrum, a feature required by gravitational-wave interferometers to
beat the standard quantum limit over an extended frequency range. Under
realistic assumptions we show that the amount of available squeezing and the
intrinsic quadrature rotation may provide, compared to similar amounts of
fixed-quadrature squeezing, a detection advantage. A significant challenge for
this scheme, however, is the amount of excess noise that is generated in the
unsqueezed quadrature at frequencies near the mechanical resonance.


title:
The Initial Conditions of Stellar Protocluster Formation: III. The
  Herschel counterparts of the Spitzer Dark Cloud catalogue

abstract:
  Galactic plane surveys of pristine molecular clouds are key for establishing
a Galactic-scale view of the earliest stages of star formation. For this reason
Peretto & Fuller (2009) built an unbiased sample of IRDCs in the 10 deg < |l| <
65 deg, |b|<1 deg region of the Galactic plane using Spitzer 8micron
extinction. However, in absorption studies, intrinsic fluctuations in the
mid-infrared background can be mis-interpreted as foreground clouds. The main
goal of the study presented here is to disentangle real clouds in the Spitzer
Dark Cloud (SDC) catalogue from artefacts due to fluctuations in the
mid-infrared background. We constructed H_2 column density maps at ~18"
resolution using the 160micron and 250micron data from the Herschel Galactic
plane survey Hi-GAL. We also developed an automated detection scheme that
confirms the existence of a SDC through its association with a peak on these
Herschel column density maps. Detection simulations, along with visual
inspection of a small sub-sample of SDCs, have been performed to get better
insight into the limitations of our automated identification scheme. Our
analysis shows that 76(+/-19)% of the catalogued SDCs are real. This fraction
drops to 55(+/-12)% for clouds with angular diameters larger than ~1 arcminute.
The contamination of the PF09 catalogue by large spurious sources reflect the
large uncertainties associated to the construction of the 8micron background
emission, a key stage towards the identification of SDCs. A comparison of the
Herschel confirmed SDC sample with the BGPS and ATLASGAL samples shows that
SDCs probe a unique range of cloud properties, reaching down to more compact
and lower column density clouds than any of these two (sub-)millimetre Galactic
plane surveys.


title:
Fast Radio Bursts as Probes of Magnetic Fields in the Intergalactic
  Medium

abstract:
  We examine the proposal that the dispersion measures (DMs) and Faraday
rotation measures (RMs) of extragalactic linearly-polarized fast radio bursts
(FRBs) can be used to probe the intergalactic magnetic field (IGMF) in
filaments of galaxies. The DM through the cosmic web is dominated by
contributions from the warm-hot intergalactic medium (WHIM) in filaments and
from the gas in voids. On the other hand, RM is induced mostly by the hot
medium in galaxy clusters, and only a fraction of it is produced in the WHIM.
We show that if one excludes FRBs whose sightlines pass through galaxy
clusters, the line-of-sight strength of the IGMF in filaments, $B_{||}$, is
approximately $C(\langle 1+z \rangle/f_{DM})(RM/DM)$, where $C$ is a known
constant. Here, the redshift of the FRB is not required to be known; $f_{DM}$
is the fraction of total DM due to the WHIM, while $\langle 1+z \rangle$ is the
redshift of interevening gas weighted by the WHIM gas density, both of which
can be evaluated for a given cosmology model solely from the DM of an FRB.
Using data on structure formation simulations and a model IGMF, we show that
$C(\langle 1+z \rangle/f_{DM})(RM/DM)$ closely reproduces the density-weighted
line-of-sight strength of the IGMF in filaments of the large-scale structure.


title: Orthogonality graph of the algebra of upper triangular matrices

abstract:
  We study the connectedness and the diameter of orthogonality graphs of upper
triangular matrix algebras over arbitrary fields.


title: Can chaos be observed in quantum gravity?

abstract:
  Full general relativity is almost certainly 'chaotic'. We argue that this
entails a notion of nonintegrability: a generic general relativistic model, at
least when coupled to cosmologically interesting matter, likely possesses
neither differentiable Dirac observables nor a reduced phase space. It follows
that the standard notion of observable has to be extended to include
non-differentiable or even discontinuous generalized observables. These cannot
carry Poisson-algebraic structures and do not admit a standard quantization;
one thus faces a quantum representation problem of gravitational observables.
This has deep consequences for a quantum theory of gravity, which we
investigate in a simple model for a system with Hamiltonian constraint that
fails to be completely integrable. We show that basing the quantization on
standard topology precludes a semiclassical limit and can even prohibit any
solutions to the quantum constraints. Our proposed solution to this problem is
to refine topology such that a complete set of Dirac observables becomes
continuous. In the toy model, it turns out that a refinement to a polymer-type
topology, as e.g. used in loop gravity, is sufficient. Basing quantization of
the toy model on this finer topology, we find a complete set of quantum Dirac
observables and a suitable semiclassical limit. This strategy is applicable to
realistic candidate theories of quantum gravity and thereby suggests a solution
to a long-standing problem which implies ramifications for the very concept of
quantization. Our work reveals a qualitatively novel facet of chaos in physics
and opens up a new avenue of research on chaos in gravity which hints at deep
insights into the structure of quantum gravity.


title:
Valuation of Variable Annuities with Guaranteed Minimum Withdrawal
  Benefit under Stochastic Interest Rate

abstract:
  A variable annuity contract with Guaranteed Minimum Withdrawal Benefit (GMWB)
promises to return the entire initial investment through cash withdrawals
during the contract plus the remaining account balance at maturity, regardless
of the portfolio performance. Under the optimal(dynamic) withdrawal strategy of
a policyholder, GMWB pricing becomes an optimal stochastic control problem that
can be solved by backward recursion of Bellman equation. In this paper we
develop a very efficient new algorithm for pricing these contracts in the case
of stochastic interest rate not considered previously in the literature.
Presently our method is applied to the Vasicek interest rate model, but it is
generally applicable to any model when transition density or moments of the
underlying asset and interest rate are known in closed form or can be evaluated
efficiently. Using bond price as a numeraire the required expectations in the
backward recursion are reduced to two-dimensional integrals calculated through
a high order Gauss-Hermite quadrature applied on a two-dimensional cubic spline
interpolation. Numerical results from the new algorithm for a series of GMWB
contracts for both static and optimal cases are presented. As a validation,
results of the algorithm are compared with the closed form solutions for simple
vanilla options, and with Monte Carlo and finite difference results for the
static GMWB. The comparison demonstrates that the new algorithm is
significantly faster than finite difference or Monte Carlo for all the
two-dimensional problems tested so far. For dynamic GMWB pricing, we found that
for positive correlation between the underlying asset and interest rate, the
GMWB price under the stochastic interest rate is significantly higher compared
to the case of deterministic interest rate, while for negative correlation the
difference is less but still significant.


title: Baire category theory and Hilbert's Tenth Problem inside $\mathbb{Q}$

abstract:
  For a ring R, Hilbert's Tenth Problem HTP(R) is the set of polynomial
equations over R, in several variables, with solutions in R. We consider
computability of this set for subrings R of the rationals. Applying Baire
category theory to these subrings, which naturally form a topological space,
relates their sets HTP(R) to the set HTP($\mathbb{Q}$), whose decidability
remains an open question. The main result is that, for an arbitrary set C,
HTP($\mathbb{Q}$) computes C if and only if the subrings R for which HTP(R)
computes C form a nonmeager class. Similar results hold for 1-reducibility, for
admitting a Diophantine model of $\mathbb{Z}$, and for existential definability
of $\mathbb{Z}$.


title: Resonance fluorescence from an artificial atom in squeezed vacuum

abstract:
  We present an experimental realization of resonance fluorescence in squeezed
vacuum. We strongly couple microwave-frequency squeezed light to a
superconducting artificial atom and detect the resulting fluorescence with high
resolution enabled by a broadband traveling-wave parametric amplifier. We
investigate the fluorescence spectra in the weak and strong driving regimes,
observing up to 3.1 dB of reduction of the fluorescence linewidth below the
ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum
on the relative phase of the driving and squeezed vacuum fields. Our results
are in excellent agreement with predictions for spectra produced by a two-level
atom in squeezed vacuum [Phys. Rev. Lett. \textbf{58}, 2539-2542 (1987)],
demonstrating that resonance fluorescence offers a resource-efficient means to
characterize squeezing in cryogenic environments.


title:
Time-and-frequency gated photon coincidence counting; a novel
  multidimensional spectroscopy tool

abstract:
  Coherent multidimensional optical spectroscopy techniques are broadly applied
across the electromagnetic spectrum ranging from NMR to the UV. These reveal
properties of matter through correlation plots of signal fields generated in
response to sequences of short pulses with variable delays. Here we discuss a
new class of multidimensional techniques obtained by time-and-frequency
resolved photon coincidence counting measurements of N photons which
constitutes a 2N dimensional spectrum. A compact description of these signals
is developed based on time ordered superoperators rather than the normally
ordered ordinary operators used in Glauber's photon counting formalism.The
independent control of the time and frequency gate parameters reveals details
of matter dynamics not available otherwise. Application to an anharmonic
oscillator model with fluctuating energy and anharmonicity demonstrates the
power of these signals.


title:
Intrinsic electromagnetic variability in celestial objects containing
  rapidly spinning black holes

abstract:
  Analytical studies have raised the concern that a mysterious expulsion of
magnetic field lines by a rapidly-spinning black hole (dubbed the black hole
Meissner effect) would shut down the Blandford-Znajek process and quench the
jets of active galactic nuclei and microquasars. This effect is however not
seen observationally or in numerical simulations. Previous attempts at
reconciling the predictions with observations have proposed several mechanisms
to evade the Meissner effect. In this paper, we identify a new evasion
mechanism and discuss its observational significance. Specifically, we show
that the breakdown of stationarity is sufficient to remove the expulsion of the
magnetic field at all multipole orders, and that the associated temporal
variation is likely turbulent due to the existence of efficient mechanisms for
sharing energy across different modes. Such an intrinsic (as opposed to being
driven externally by, e.g., changes in the accretion rate) variability of the
electromagnetic field can produce the recorded linear correlation between
microvariability amplitudes and mean fluxes, help create magnetic randomness
and seed sheared magnetic loops in jets, and lead to a better theoretical fit
to the X-ray microvariability power spectral density.


title:
Reservoir interactions of a vortex in a trapped 3D Bose-Einstein
  condensate

abstract:
  We simulate the dissipative evolution of a vortex in a trapped
finite-temperature dilute-gas Bose-Einstein condensate using first-principles
open-systems theory. Simulations of the complete stochastic projected
Gross-Pitaevskii equation for a partially condensed Bose gas containing a
single quantum vortex show that the transfer of condensate energy to the
incoherent thermal component without population transfer provides an important
channel for vortex decay. For the lower temperatures considered, this effect is
significantly larger that the population transfer process underpinning the
standard theory of vortex decay, and is the dominant determinant of the vortex
lifetime. A comparison with the Zaremba-Nikuni-Griffin kinetic (two-fluid)
theory further elucidates the role of the particle transfer interaction, and
suggests the need for experimental testing of reservoir interaction theory. The
dominance of this particular energetic decay mechanism for this open quantum
system should be testable with current experimental setups, and its observation
would have broad implications for the dynamics of atomic matter waves and
experimental studies of dissipative phenomena.


title:
Development of a Computationally Optimized Model of Cancer-induced
  Angiogenesis through Specialized Cellular Mechanics

abstract:
  Angiogenesis, the development of new vasculature, is a critical process in
the growth of new tumors. Driven by a goal to understand this aspect of cancer
proliferation, I develop a discrete computationally optimized mathematical
model of angiogenesis that specializes in intercellular interactions. I model
vascular endothelial growth factor spread and dynamics of endothelial cell
movement in a competitive environment, with parameters specific to our model
calculated through Dependent Variable Sensitivity Analysis (DVSA) and
experimentally observed data. Through simulation testing, we find the critical
limits of angiogenesis to be 102 m and 153 m respectively, beyond which
angiogenesis will not successfully occur. Cell density in the surrounding
region and the concentration of extracellular matrix fibers are also found to
directly inhibit angiogenesis. Through these three factors, we postulate a
method for establishing criticality of a tumor based upon the likelihood of
angiogenesis completing. This research expands on other work by choosing
factors that are patient-dependent through our specialized Cellular Potts mode,
which serves to optimize and increase accuracy of the model. By doing such, I
establish a theoretical framework for analyzing lesions using angiogenetic
properties, with the ability to potentially compute the criticality of tumors
with the aid of medical imaging technology.


title:
Nanoscale control of rewriteable doping patterns in pristine
  graphene/boron nitride heterostructures

abstract:
  Nanoscale control of charge doping in two-dimensional (2D) materials permits
the realization of electronic analogs of optical phenomena, relativistic
physics at low energies, and technologically promising nanoelectronics.
Electrostatic gating and chemical doping are the two most common methods to
achieve local control of such doping. However, these approaches suffer from
complicated fabrication processes that introduce contamination, change material
properties irreversibly, and lack flexible pattern control. Here we demonstrate
a clean, simple, and reversible technique that permits writing, reading, and
erasing of doping patterns for 2D materials at the nanometer scale. We
accomplish this by employing a graphene/boron nitride (BN) heterostructure that
is equipped with a bottom gate electrode. By using electron transport and
scanning tunneling microscopy (STM), we demonstrate that spatial control of
charge doping can be realized with the application of either light or STM tip
voltage excitations in conjunction with a gate electric field. Our
straightforward and novel technique provides a new path towards on-demand
graphene pn junctions and ultra-thin memory devices.


title:
Reliability Polynomials of Simple Graphs having Arbitrarily many
  Inflection Points

abstract:
  In this paper we show that for each $n$, there exists a simple graph whose
reliability polynomial has at least $n$ inflection points.


title: Exploring Dynamic Environments Using Stochastic Search Strategies

abstract:
  In this paper, we conduct a literature review of laws of motion based on
stochastic search strategies which are mainly focused on exploring highly
dynamic environments. In this regard, stochastic search strategies represent an
interesting alternative to cope with uncertainty and reduced perceptual
capabilities. This study aims to present an introductory overview of research
in terms of directional rules and searching methods mainly based on
bio-inspired approaches. This study critically examines the role of animal
searching behavior applied to random walk models using stochastic rules and
kinesis or taxis. The aim of this study is to examine existing techniques and
to select relevant work on random walks and analyze their actual contributions.
In this regard, we cover a wide range of displacement events with an
orientation mechanism given by a reactive behavior or a source-seeking
behavior. Finally, we conclude with a discussion concerning the usefulness of
using optimal foraging strategies as a reliable methodology.


title: FFLO Excitonic State in the Three-Chain Hubbard Model for Ta$_2$NiSe$_5$

abstract:
  The three-chain Hubbard model for Ta$_2$NiSe$_5$ known as a candidate
material for the excitonic insulator is investigated over the wide range of
energy gap $D$ between the two-fold degenerate conduction bands and the
nondegenerate valence band including both semiconducting ($D>0$) and
semimetallic ($D<0$) cases. In the semimetallic case, the difference of the
band degeneracy inevitably causes the imbalance of each Fermi wavenumber,
resulting in a remarkable excitonic state characterized by the condensation of
excitons with finite center-of-mass momentum $q$, the so-called
Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) excitonic state. With decreasing $D$
corresponding to increasing pressure, the obtained excitonic phase diagram
shows a crossover from BEC ($D\simg 0$) to BCS ($D\siml 0$) regime, and then
shows a distinct phase transition at a certain critical value $D_c(<0)$ from
the uniform ($q=0$) to the FFLO ($q\ne 0$) excitonic state, as expected to be
observed in Ta$_2$NiSe$_5$ under high pressure.


title:
A high-resolution pointing system for fast scanning platforms: The EBEX
  example

abstract:
  The E and B experiment (EBEX) is a balloon-borne telescope designed to
measure the polarization of the cosmic microwave background with 8' resolution
employing a gondola scanning with speeds of order degree per second. In January
2013, EBEX completed 11 days of observations in a flight over Antarctica
covering $\sim$ 6000 square degrees of the sky. The payload is equipped with
two redundant star cameras and two sets of three orthogonal gyroscopes to
reconstruct the telescope attitude. The EBEX science goals require the pointing
to be reconstructed to approximately 10" in the map domain, and in-flight
attitude control requires the real time pointing to be accurate to $\sim$
0.5$^{\circ}$ . The high velocity scan strategy of EBEX coupled to its float
altitude only permits the star cameras to take images at scan turnarounds,
every $\sim$ 40 seconds, and thus requires the development of a pointing system
with low noise gyroscopes and carefully controlled systematic errors. Here we
report on the design of the pointing system and on a simulation pipeline
developed to understand and minimize the effects of systematic errors. The
performance of the system is evaluated using the 2012/2013 flight data, and we
show that we achieve a pointing error with RMS=25" on 40 seconds azimuth
throws, corresponding to an error of $\sim$ 4.6" in the map domain.


title: Logarithmic Intertwining Operators and Genus-One Correlation Functions

abstract:
  This is the first of two papers in which we study the modular invariance of
pseudotraces of logarithmic intertwining operators. We construct and study
genus-one correlation functions for logarithmic intertwining operators among
generalized modules over a positive-energy and $C_2$-cofinite vertex operator
algebra $V$. We consider grading-restricted generalized $V$-modules which admit
a right action of some associative algebra $P$, and intertwining operators
among such modules which commute with the action of $P$ ($P$-intertwining
operators). We obtain duality properties, i.e., suitable associativity and
commutativity properties, for $P$-intertwining operators. Using pseudotraces
introduced by Miyamoto and studied by Arike, we define formal $q$-traces of
products of $P$-intertwining operators, and obtain certain identities for these
formal series. This allows us to show that the formal $q$-traces satisfy a
system of differential equations with regular singular points, and therefore
are absolutely convergent in a suitable region and can be extended to yield
multivalued analytic functions, called genus-one correlation functions.
Furthermore, we show that the space of solutions of these differential
equations is invariant under the action of the modular group.


title:
Exponential suppression of decoherence and relaxation of quantum systems
  using energy penalty

abstract:
  One of the main methods for protecting quantum information against
decoherence is to encode information in the ground subspace (or the low energy
sector) of a Hamiltonian with a large energy gap which penalizes errors from
environment. The protecting Hamiltonian is chosen such that its degenerate
ground subspace is an error detecting code for the errors caused by the
interaction with the environment. We consider environments with arbitrary
number of local sites, e.g. spins, whose interactions among themselves are
local and bounded. Then, assuming the system is interacting with a finite
number of sites in the environment, we prove that, up to second order with
respect to the coupling constant, decoherence and relaxation are suppressed by
a factor which grows exponentially fast with the ratio of energy penalty to the
norm of local interactions in the environment. The state may, however, still
evolve unitarily inside the code subspace due to the Lamb shift effect. In the
context of adiabatic quantum computation, this means that the evolution inside
the code subspace is effectively governed by a renormalized Hamiltonian. The
result is derived from first principles, without use of master equations or
their assumptions, and holds even in the infinite temperature limit. We also
prove that unbounded or non-local interactions in the environment at sites far
from the system do not considerably modify the exponential suppression. Our
main technical tool is a new bound on the decay of power spectral density at
high frequencies for local observables and many-body Hamiltonians with bounded
and local interactions in a neighborhood around the support of the observable.

categories: quant-ph cond-mat.dis-nn cond-mat.str-el math-ph math.MP


title: Uncovering the behavior of Hf2Te2P and the candidate Dirac metal Zr2Te2P

abstract:
  Results are reported for single crystal specimens of Hf$_2$Te$_2$P and
compared to its structural analogue Zr$_2$Te$_2$P, which was recently proposed
to be a potential reservoir for Dirac physics.[1] Both materials are produced
using the iodine vapor transport method and the resulting crystals are
exfoliable. The bulk electrical transport and thermodynamic properties indicate
Fermi liquid behavior at low temperature for both compounds. Quantum
oscillations are observed in magnetization measurements for fields applied
parallel but not perpendicular to the $c$-axis, suggesting that the Fermi
surfaces are quasi-two dimensional. Frequencies are determined from quantum
oscillations for several parts of the Fermi surfaces. Lifshitz-Kosevich fits to
the temperature dependent amplitudes of the oscillations reveal small effective
masses, with a particularly small value $m^*$ $=$ 0.046$m_0$ for the {\alpha}
branch of Zr$_2$Te$_2$P. Electronic structure calculations are in good
agreement with quantum oscillation results and illustrate the effect of a
stronger spin-orbit interaction going from Zr to Hf. These results suggest that
by using appropriate tuning parameters this class of materials may deepen the
pool of novel Dirac phenomena.


title:
A Kernelized Stein Discrepancy for Goodness-of-fit Tests and Model
  Evaluation

abstract:
  We derive a new discrepancy statistic for measuring differences between two
probability distributions based on combining Stein's identity with the
reproducing kernel Hilbert space theory. We apply our result to test how well a
probabilistic model fits a set of observations, and derive a new class of
powerful goodness-of-fit tests that are widely applicable for complex and high
dimensional distributions, even for those with computationally intractable
normalization constants. Both theoretical and empirical properties of our
methods are studied thoroughly.


title:
Proceedings Eighth International Workshop on Programming Language
  Approaches to Concurrency- and Communication-cEntric Software

abstract:
  PLACES 2015 (full title: Programming Language Approaches to Concurrency- and
Communication-Centric Software) is the eighth edition of the PLACES workshop
series. After the first PLACES, which was affiliated to DisCoTec in 2008, the
workshop has been part of ETAPS every year since 2009 and is now an established
part of the ETAPS satellite events. PLACES 2015 was held on 18th April in
London, UK.
  The workshop series was started in order to promote the application of novel
programming language ideas to the increasingly important problem of developing
software for systems in which concurrency and communication are intrinsic
aspects. This includes software for both multi-core systems and large-scale
distributed and/or service-oriented systems. The scope of PLACES includes new
programming language features, whole new programming language designs, new type
systems, new semantic approaches, new program analysis techniques, and new
implementation mechanisms.
  This volume consists of revised versions of the papers that were presented at
the workshop.


title: Rough path theory and stochastic calculus

abstract:
  T. Lyons' rough path theory is something like a deterministic version of K.
Ito's theory of stochastic differential equations, combined with ideas from K.
T. Chen's theory of iterated path integrals. In this article we survey rough
path theory, in particular, its probabilistic aspects.


title: Improved Eigenfeature Regularization for Face Identification

abstract:
  In this work, we propose to divide each class (a person) into subclasses
using spatial partition trees which helps in better capturing the
intra-personal variances arising from the appearances of the same individual.
We perform a comprehensive analysis on within-class and within-subclass
eigenspectrums of face images and propose a novel method of eigenspectrum
modeling which extracts discriminative features of faces from both
within-subclass and total or between-subclass scatter matrices. Effective
low-dimensional face discriminative features are extracted for face recognition
(FR) after performing discriminant evaluation in the entire eigenspace.
Experimental results on popular face databases (AR, FERET) and the challenging
unconstrained YouTube Face database show the superiority of our proposed
approach on all three databases.


title: Asymptotics of mean-field $O(N)$ models

abstract:
  We study mean-field classical $N$-vector models, for integers $N\ge 2$. We
use the theory of large deviations and Stein's method to study the total spin
and its typical behavior, specifically obtaining non-normal limit theorems at
the critical temperatures and central limit theorems away from criticality.
Important special cases of these models are the XY ($N=2$) model of
superconductors, the Heisenberg ($N=3$) model (previously studied in \cite{KM}
but with a correction to the critical distribution here), and the Toy ($N=4$)
model of the Higgs sector in particle physics.


title: Interactive Bayesian Hierarchical Clustering

abstract:
  Clustering is a powerful tool in data analysis, but it is often difficult to
find a grouping that aligns with a user's needs. To address this, several
methods incorporate constraints obtained from users into clustering algorithms,
but unfortunately do not apply to hierarchical clustering. We design an
interactive Bayesian algorithm that incorporates user interaction into
hierarchical clustering while still utilizing the geometry of the data by
sampling a constrained posterior distribution over hierarchies. We also suggest
several ways to intelligently query a user. The algorithm, along with the
querying schemes, shows promising results on real data.


title: Cyclic Pursuit on Compact Manifolds

abstract:
  We study a form of cyclic pursuit on Riemannian manifolds with positive
injectivity radius. We conjecture that on a compact manifold, the piecewise
geodesic loop formed by connecting consecutive pursuit agents either collapses
in finite time or converges to a closed geodesic. The main result is that this
conjecture is valid for nonpositively curved compact manifolds.


title:
A Nonconforming Finite Element Method for the Biot's Consolidation Model
  in Poroelasticity

abstract:
  A stable finite element scheme that avoids pressure oscillations for a
three-field Biot's model in poroelasticity is considered. The involved
variables are the displacements, fluid flux (Darcy velocity), and the pore
pressure, and they are discretized by using the lowest possible approximation
order: Crouzeix-Raviart finite elements for the displacements, lowest order
Raviart-Thomas-Nedelec elements for the Darcy velocity, and piecewise constant
approximation for the pressure. Mass lumping technique is introduced for the
Raviart-Thomas-Nedelec elements in order to eliminate the Darcy velocity and,
therefore, reduce the computational cost. We show convergence of the discrete
scheme which is implicit in time and use these types of elements in space with
and without mass lumping. Finally, numerical experiments illustrate the
convergence of the method and show its effectiveness to avoid spurious pressure
oscillations when mass lumping for the Raviart-Thomas-Nedelec elements is used.


title: Coherence-Driven Topological Transition in Quantum Metamaterials

abstract:
  We introduce and theoretically demonstrate a quantum metamaterial made of
dense ultracold neutral atoms loaded into an inherently defect-free artificial
crystal of light, immune to well-known critical chal- lenges inevitable in
conventional solid-state platforms. We demonstrate an all-optical control on
ultrafast time scales over the photonic topological transition of the
isofrequency contour from an open to close topology at the same frequency. This
atomic lattice quantum metamaterial enables a dynamic manipula- tion of the
decay rate of a probe quantum emitter by more than an order of magnitude. This
proposal may lead to practically lossless, tunable and
topologically-reconfigurable quantum metamaterials, for single- or
few-photon-level applications as varied as quantum sensing, quantum information
processing, and quantum simulations using metamaterials.


title:
Interface-Flattening Transform for EM Field Modeling in Tilted,
  Cylindrically-Stratified Geophysical Media

abstract:
  We propose and investigate an "interface-flattening" transformation, hinging
upon Transformation Optics (T.O.) techniques, to facilitate the rigorous
analysis of electromagnetic (EM) fields radiated by sources embedded in tilted,
cylindrically-layered geophysical media. Our method addresses the major
challenge in such problems of appropriately approximating the domain boundaries
in the computational model while, in a full-wave manner, predicting the effects
of tilting in the layers. When incorporated into standard pseudo-analytical
algorithms, moreover, the proposed method is quite robust, as it is not limited
by absorption, anisotropy, and/or eccentering profile of the cylindrical
geophysical formations, nor is it limited by the radiation frequency. These
attributes of the proposed method are in contrast to past analysis methods for
tilted-layer media that often place limitations on the source and medium
characteristics. Through analytical derivations as well as a preliminary
numerical investigation, we analyze and discuss the method's strengths and
limitations.


title:
Harmonic Analysis on the Positive Rationals. Determination of the Group
  Generated by the Ratios $(an+b)/(An+B)$

abstract:
  The authors show how to determine the group generated by the ratios
$(an+b)/(An+B)$ through its dual.


title: A Theory of Generative ConvNet

abstract:
  We show that a generative random field model, which we call generative
ConvNet, can be derived from the commonly used discriminative ConvNet, by
assuming a ConvNet for multi-category classification and assuming one of the
categories is a base category generated by a reference distribution. If we
further assume that the non-linearity in the ConvNet is Rectified Linear Unit
(ReLU) and the reference distribution is Gaussian white noise, then we obtain a
generative ConvNet model that is unique among energy-based models: The model is
piecewise Gaussian, and the means of the Gaussian pieces are defined by an
auto-encoder, where the filters in the bottom-up encoding become the basis
functions in the top-down decoding, and the binary activation variables
detected by the filters in the bottom-up convolution process become the
coefficients of the basis functions in the top-down deconvolution process. The
Langevin dynamics for sampling the generative ConvNet is driven by the
reconstruction error of this auto-encoder. The contrastive divergence learning
of the generative ConvNet reconstructs the training images by the auto-encoder.
The maximum likelihood learning algorithm can synthesize realistic natural
image patterns.