title: Causal influence in linear response models

abstract:
  The intuition of causation is so fundamental that almost every research study
in life sciences refers to this concept. However a widely accepted formal
definition of causal influence between observables is still missing. In the
framework of linear Langevin networks without feedbacks (linear response
models) we developed a measure of causal influence based on a decomposition of
information flows over time. We discuss its main properties and compare it with
other information measures like the Transfer Entropy. Finally we outline some
difficulties of the extension to a general definition of causal influence for
complex systems.


title:
Analytical On-shell Calculation of Higher Order Scattering: Massless
  Particles

abstract:
  We demonstrate that the use of on-shell methods involving calculation of the
discontinuity across the t-channel cut associated with the exchange of a pair
of massless particles can be used to evaluate loop contributions to the
electromagnetic and gravitational scattering of both massive and massless
particles. In the gravitational case the use of factorization permits a
straightforward and algebraic calculation of higher order scattering results,
which were obtained previously by considerably more arduous Feynman diagram
techniques.


title: Phase transitions of extremal cuts for the configuration model

abstract:
  The $k$-section width and the Max-Cut for the configuration model are shown
to exhibit phase transitions according to the values of certain parameters of
the asymptotic degree distribution. These transitions mirror those observed on
Erd\H{o}s-R\'enyi random graphs, established by Luczak and McDiarmid (2001),
and Coppersmith et al. (2004), respectively.


title: Measurement of the CKM angle $\gamma$ from a combination of LHCb results

abstract:
  A combination of measurements sensitive to the CKM angle $\gamma$ from LHCb
is performed. The inputs are from analyses of time-integrated $B^{+}\rightarrow
DK^+$, $B^{0} \rightarrow D K^{*0}$, $B^{0} \rightarrow D K^+ \pi^-$ and $B^{+}
\rightarrow D K^+\pi^+\pi^-$ tree-level decays. In addition, results from a
time-dependent analysis of $B_{s}^{0} \rightarrow D_{s}^{\mp}K^{\pm}$ decays
are included. The combination yields $\gamma = (72.2^{+6.8}_{-7.3})^\circ$,
where the uncertainty includes systematic effects. The 95.5% confidence level
interval is determined to be $\gamma \in [55.9,85.2]^\circ$. A second
combination is investigated, also including measurements from $B^{+}
\rightarrow D \pi^+$ and $B^{+} \rightarrow D \pi^+\pi^-\pi^+$ decays, which
yields compatible results.


title:
Comparative effect of an addition of a surface term to the Woods-Saxon
  potential on the thermodynamics of a nucleon

abstract:
  In this study, we reveal the difference between Woods-Saxon (WS) and
Generalized Symmetric Woods-Saxon (GSWS) potentials in order to describe the
physical properties of a nucleon, by means of solving Schr\"odinger eq. for the
two potentials. The additional term squeezes the WS potential well, which leads
an upward shift in the spectrum, resulting in a more realistic picture. The
resulting GSWS potential does not merely accommodate extra quasi bound states,
but also has modified bound state spectrum. As an application, we apply the
formalism to a real problem, an $\alpha$ particle confined in Bohrium-$270$
nucleus. The thermodynamic functions Helmholtz energy, entropy, internal
energy, specific heat of the system are calculated and compared for both wells.
The internal energy and the specific heat capacity increase as a result of
upward shift in the spectrum. The shift of the Helmholtz free energy is a
direct consequence of the shift of the spectrum. The entropy decreases because
of a decrement in the number of available states.


title: Topology as faithful communication through relations

abstract:
  Basic pairs and their morphisms are the most elementary framework in which
standard topological notions can be defined. We present here a new
interpretation of topological concepts as those which can be communicated
faithfully between the two sides of basic pairs. In particular, we prove that
the subsets which can be communicated faithfully (in the suitable way) are
exactly open subsets and closed subsets. We also prove that a relation (and in
particular a function) between two sets of points can be communicated
faithfully if and only if it is continuous.


title: Fractal Art Generation using GPUs

abstract:
  Fractal image generation algorithms exhibit extreme parallelizability. Using
general purpose graphics processing unit (GPU) programming to implement
escape-time algorithms for Julia sets of functions,parallel methods generate
visually attractive fractal images much faster than traditional methods. Vastly
improved speeds are achieved using this method of computation, which allow
real-time generation and display of images. A comparison is made between
sequential and parallel implementations of the algorithm. An application
created by the authors demonstrates using the increased speed to create dynamic
imaging of fractals where the user may explore paths of parameter values
corresponding to a given function's Mandelbrot set. Examples are given of
artistic and mathematical insights gained by experiencing fractals
interactively and from the ability to sample the parameter space quickly and
comprehensively.


title:
Accuracy estimation of the 16O2+ transition frequencies targeting the
  search for the variation in mp/me

abstract:
  The precise measurement of molecular vibrational transition frequencies is
useful in the search for variation in the proton-to-electron mass ratio {\mu}.
Homonuclear diatomic molecules are particularly advantageous for precise
measurement because of the small Stark shift. This paper discusses the Stark
and Zeeman shifts in the 16O2+ vibrational transition frequencies.To search for
the variation {\mu}(<10-17/yr), the X2{\Pi}1/2(v,J)=(0,1/2)-(v',1/2)(v'>1)in
transition frequencies are much more advantageous than the transition
frequencies between the X2{\Pi}1/2 v=21 and a4{\Pi}1/2 v=0 states, whose
sensitivity to the variation in {\mu} is high because of the accidental
degeneracy.


title:
VR 'SPACE OPERA': Mimetic Spectralism in an Immersive Starlight
  Audification System

abstract:
  This paper describes a system designed as part of an interactive VR opera,
which immerses a real-time composer and an audience (via a network) in the
historical location of Gobeklitepe, in southern Turkey during an imaginary
scenario set in the Pre-Pottery Neolithic period (8500-5500 BCE), viewed by
some to be the earliest example of a temple, or observatory. In this scene
music is generated, where the harmonic material is determined based on
observations of light variation from pulsating stars, that would have
theoretically been overhead on the 1st of October 8000 BC at 23:00 and animal
calls based on the reliefs in the temple. Based on the observations of the
stars V465 Per, HD 217860, 16 Lac, BG CVn and KIC 6382916, frequency
collections were derived and applied to the generation of musical sound and
notation sequences within a custom VR environment using a novel method
incorporating spectralist techniques. Parameters controlling this 'resynthesis'
can be manipulated by the performer using a Leap Motion controller and Oculus
Rift HMD, yielding both sonic and visual results in the environment. The final
opera is to be viewed via Google Cardboard and delivered over the Internet.
This entire process aims to pose questions about real-time composition through
time distortion and invoke a sense of wonder and meaningfulness through a
ritualistic experience.


title: Optical variability of AGN in the PTF/iPTF survey

abstract:
  We characterize the optical variability of quasars in the intermediate
Palomar Transient Factory (iPTF) and Palomar Transient Factory (PTF) surveys.
We re-calibrate the $r$-band light curves for $\sim$28,000 luminous, broad-line
AGNs from the SDSS, producing a total of $\sim$2.4 million photometric data
points. We utilize both the structure function (SF) and power spectrum density
(PSD) formalisms to search for links between the optical variability and the
physical parameters of the accreting supermassive black holes that power the
quasars. The excess variance (SF$^{2}$) of the quasar sample tends to zero at
very short time separations, validating our re-calibration of the time-series
data. We find that the the amplitude of variability at a given time-interval,
or equivalently the time-scale of variability to reach a certain amplitude, is
most strongly correlated with luminosity with weak or no dependence on black
hole mass and redshift. For a variability level of SF($\tau$)=0.07 mag, the
time-scale has a dependency of $\tau \propto L^{0.4}$. This is broadly
consistent with the expectation from a simple Keplerian accretion disk model,
which provides $\tau \propto L^{0.5}$. The PSD analysis also reveals that many
quasar light curves are steeper than a damped random walk. We find a
correlation between the steepness of the PSD slopes, specifically the fraction
of slopes steeper than 2.5, and black hole mass, although we cannot exclude the
possibility that luminosity or Eddington ratio are the drivers of this effect.
This effect is also seen in the SF analysis of the (i)PTF data, and in a PSD
analysis of quasars in the SDSS Stripe 82.


title: Atmospheric Signatures of Giant Exoplanet Formation by Pebble Accretion

abstract:
  Atmospheric chemical abundances of giant planets lead to important
constraints on planetary formation and migration. Studies have shown that giant
planets that migrate through the protoplanetary disk can accrete substantial
amounts of oxygen-rich planetesimals, leading to super-solar metallicities in
the envelope and solar or sub-solar C/O ratios. Pebble accretion has been
demonstrated to play an important role in core accretion and to have growth
rates that are consistent with planetary migration. The high pebble accretion
rates allow planetary cores to start their growth beyond 10 AU and subsequently
migrate to cold (>~ 1 AU), warm (~0.1 AU- 1AU) or hot (<~ 0.1 AU) orbits. In
this work we investigate how the formation of giant planets via pebble
accretion influences their atmospheric chemical compositions. We find that
under the standard pebble accretion scenario, where the core is isolated from
the envelope, the resulting metallicities (O/H and C/H ratios) are sub-solar,
while the C/O ratios are super-solar. Planets that migrate through the disk to
become hot Jupiters accrete substantial amounts of water vapour, but still
acquire slightly sub-solar O/H and super-solar C/O of 0.7-0.8. The metallicity
can be substantially sub-solar (~0.2-0.5x solar) and the C/O can even approach
1.0 if the planet accretes its envelope mostly beyond the CO2 ice line, i.e.
cold Jupiters or hot Jupiters that form far out and migrate in by scattering.
Allowing for core erosion yields significantly super-solar metallicities and
solar or sub-solar C/O, which can also be achieved by other means, e.g.
photo-evaporation and late-stage planetesimal accretion.


title:
The SCUBA-2 Cosmology Legacy Survey: Multi-wavelength Properties of
  ALMA-identified Submillimeter Galaxies in UKIDSS-UDS

abstract:
  We present a multi-wavelength analysis of 52 sub-millimeter galaxies (SMGs),
identified using ALMA 870$\mu$m continuum imaging in a pilot program to
precisely locate bright SCUBA2-selected sub-mm sources in the UKIDSS Ultra Deep
Survey (UDS) field. Using the available deep (especially near-infrared),
panoramic imaging of the UDS field at optical-to-radio wavelengths we
characterize key properties of the SMG population. The median photometric
redshift of the bright ALMA/SCUBA-2 UDS (AS2UDS) SMGs that are detected in a
sufficient number of wavebands to derive a robust photometric redshift is
$z$=2.65$\pm$0.13. However, similar to previous studies, 27% of the SMGs are
too faint at optical-to-near-infrared wavelengths to derive a reliable
photometric redshift. Assuming that these SMGs lie at z$\gtrsim$3 raises the
median redshift of the full sample to $z$=2.9$\pm$0.2. A subset of 23,
unlensed, bright AS2UDS SMGs have sizes measured from resolved imaging of their
rest-frame far-infrared emission. We show that the extent and luminosity of the
far-infrared emission are consistent with the dust emission arising from
regions that are optically thick, on average, at a wavelength of
$\lambda_0$$\ge$75$\mu$m (1-$\sigma$ dispersion of 55-90$\mu$m). Using the dust
masses derived from our optically-thick spectral energy distribution models we
determine that these galaxies have a median hydrogen column density of
$N_{H}$=9.8$_{-0.7}^{+1.4}$$\times$10$^{23}$cm$^{-2}$, or a corresponding
median $V$-band obscuration of $A_\mathrm{v}$=540$^{+80}_{-40}$mag, averaged
along the line of sight to the source of their restframe $\sim$200$\mu$m
emission. We discuss the implications of this extreme attenuation by dust for
the multiwavelength study of dusty starbursts and reddening-sensitive tracers
of star formation.


title:
Mt. Wendelstein Imaging of the Post-Perihelion Dust Coma of
  67P/Churyumov-Gerasimenko in 2015/2016

abstract:
  Comet 67P/Churyumov-Gerasimenko (67P) was imaged with the 2m telescope at Mt.
Wendelstein Observatory in the Alps. Coma and tail monitoring was performed
during 51 nights between 22 August 2015 and 9 May 2016. The images through r
and i Sloan Digital Sky Survey (SDSS) filters show the dust distribution around
the comet, while images in the SDSS g filter indicate also the presence of coma
gas in early September 2015. The dust color of 67P implies intrinsic reddening
of 9 %/100nm. After maximum shortly after perihelion passage the dust activity
decreased with a heliocentric exponent of 4.1 to 4.2 from late September 2015
until May 2016. The opposition surge during early 2016 can be explained by a
linear light scattering phase function (beta ~ 0.04) or an asteroid-like
HG-type phase function (G ~ 0.15). The radial brightness profile indicates a
'quasi-steady-state' dust coma from late September to the end of 2015. Dust
fragmentation during about a month after perihelion may be responsible for
radial coma profiles with slopes below unity, while dust accumulation due to
very slow dust expansion velocity may result in steeper than unity profiles
during 2016. Three fan-shape dust structures are characterized in the coma of
67P. A short dust ejection event on 22 -23 August 2015 has produced a dust
arc-let and jet feature in the coma. In September 2015 the appearance of
cometary dust tail is dominated by young dust produced around perihelion. The
older dust dominates the tail appearance as of mid November 2015.


title:
APOGEE Chemical Abundances of Globular Cluster Giants in the Inner
  Galaxy

abstract:
  We report chemical abundances obtained by SDSS-III/APOGEE for giant stars in
five globular clusters located within 2.2 kpc of the Galactic centre. We detect
the presence of multiple stellar populations in four of those clusters (NGC
6553, NGC 6528, Terzan 5, and Palomar 6) and find strong evidence for their
presence in NGC 6522. All clusters present a significant spread in the
abundances of N, C, Na, and Al, with the usual correlations and
anti-correlations between various abundances seen in other globular clusters.
Our results provide important quantitative constraints on theoretical models
for self-enrichment of globular clusters, by testing their predictions for the
dependence of yields of elements such as Na, N, C, and Al on metallicity. They
also confirm that, under the assumption that field N-rich stars originate from
globular cluster destruction, they can be used as tracers of their parental
systems in the high- metallicity regime.


title:
A new approach for obtaining cosmological constraints from Type Ia
  Supernovae using Approximate Bayesian Computation

abstract:
  Cosmological parameter estimation techniques that robustly account for
systematic measurement uncertainties will be crucial for the next generation of
cosmological surveys. We present a new analysis method, superABC, for obtaining
cosmological constraints from Type Ia supernova (SN Ia) light curves using
Approximate Bayesian Computation (ABC) without any likelihood assumptions. The
ABC method works by using a forward model simulation of the data where
systematic uncertainties can be simulated and marginalized over. A key feature
of the method presented here is the use of two distinct metrics, the `Tripp'
and `Light Curve' metrics, which allow us to compare the simulated data to the
observed data set. The Tripp metric takes as input the parameters of models fit
to each light curve with the SALT-II method, whereas the Light Curve metric
uses the measured fluxes directly without model fitting. We apply the superABC
sampler to a simulated data set of $\sim$1000 SNe corresponding to the first
season of the Dark Energy Survey Supernova Program. Varying $\Omega_m, w_0,
\alpha$ and $\beta$ and a magnitude offset parameter, with no systematics we
obtain $\Delta(w_0) = w_0^{\rm true} - w_0^{\rm best \, fit} = -0.036\pm0.109$
(a $\sim11$% 1$\sigma$ uncertainty) using the Tripp metric and $\Delta(w_0) =
-0.055\pm0.068$ (a $\sim7$% 1$\sigma$ uncertainty) using the Light Curve
metric. Including 1% calibration uncertainties in four passbands, adding 4 more
parameters, we obtain $\Delta(w_0) = -0.062\pm0.132$ (a $\sim14$% 1$\sigma$
uncertainty) using the Tripp metric. Overall we find a $17$% increase in the
uncertainty on $w_0$ with systematics compared to without. We contrast this
with a MCMC approach where systematic effects are approximately included. We
find that the MCMC method slightly underestimates the impact of calibration
uncertainties for this simulated data set.


title: Spin Localization of a Fermi Polaron in a Quasirandom Optical Lattice

abstract:
  Recently, the topics of many-body localization (MBL) and one-dimensional
strongly interacting few-body systems have received a lot of interest. These
two topics have been largely developed separately. However, the generality of
the latter as far as external potentials are concerned -- including random and
quasirandom potentials -- and their shared spatial dimensionality, makes it an
interesting way of dealing with MBL in the strongly interacting regime.
Utilising tools developed for few-body systems we look to gain insight into the
localization properties of the spin in a Fermi gas with strong interactions. We
observe a delocalized--localized transition over a range of fillings of a
quasirandom lattice. We find this transition to be of a different nature for
low and high fillings, due to the diluteness of the system for low fillings.


title: Theory of Coulomb Drag in Spatially Inhomogeneous Materials

abstract:
  Coulomb drag between parallel two-dimensional electronic layers is an
excellent tool for the study of electron-electron interactions. In actual
experiments, the layers display spatial charge density fluctuations due to
imperfections such as external charged impurities. However, at present a
systematic way of taking these inhomogeneities into account in drag
calculations has been lacking, making the interpretation of experimental data
problematic. On the other hand, there exists a highly successful and widely
accepted formalism describing transport within single inhomogeneous layers
known as effective medium theory. In this work, we generalize the standard
effective medium theory to the case of Coulomb drag between two inhomogeneous
sheets and demonstrate that inhomogeneity in the layers has a strong impact on
drag transport. In the case of exciton condensation between the layers, we show
that drag resistivity takes on a value determined by the amplitude of density
fluctuation. Next we consider drag between graphene sheets, in which the
existence of spatial charge density fluctuations is well-known. We show that
these inhomogeneities play a crucial role in explaining existing experimental
data. In particular, the temperature dependence of the experimentally observed
peaks in drag resistivity can only be explained by taking the layer density
fluctuations into account. We also propose a method of extracting information
on the correlations between the inhomogeneities of the layers. The effective
medium theory of Coulomb drag derived here is general and applies to all
two-dimensional materials.


title: Generalized problem of Apollonius

abstract:
  The aim of this paper is to generalize Apollonius' problem. The problem is to
construct a circle that is tangent to three given circles in a plane. We find
the maximum possible number of solution circles in the case of more than the
three given circles. We show that if all the given circles are not tangent at
the same point, then there exist at most six solutions in the case of the four
given generalized circles and there exist at most four solutions in the case of
the five given generalized circles. We also describe all quadruples of
generalized circles with exactly six solutions.


title: Gamma-ray burst progenitors

abstract:
  We review our current understanding of the progenitors of both long and short
duration gamma-ray bursts (GRBs). Constraints can be derived from multiple
directions, and we use three distinct strands; i) direct observations of GRBs
and their host galaxies, ii) parameters derived from modeling, both via
population synthesis and direct numerical simulation and iii) our understanding
of plausible analog progenitor systems observed in the local Universe. From
these joint constraints, we describe the likely routes that can drive massive
stars to the creation of long GRBs, and our best estimates of the scenarios
that can create compact object binaries which will ultimately form short GRBs,
as well as the associated rates of both long and short GRBs. We further discuss
how different the progenitors may be in the case of black hole engine or
millisecond-magnetar models for the production of GRBs, and how central engines
may provide a unifying theme between many classes of extremely luminous
transient, from luminous and super-luminous supernovae to long and short GRBs.


title: The Local [CII] 158 um Emission Line Luminosity Function

abstract:
  We present, for the first time, the local [CII] 158 um emission line
luminosity function measured using a sample of more than 500 galaxies from the
Revised Bright Galaxy Sample (RBGS). [CII] luminosities are measured from the
Herschel PACS observations of the Luminous Infrared Galaxies in the Great
Observatories All-sky LIRG Survey (GOALS) and estimated for the rest of the
sample based on the far-IR luminosity and color. The sample covers 91.3% of the
sky and is complete at S_60 um > 5.24 Jy. We calculated the completeness as a
function of [CII] line luminosity and distance, based on the far-IR color and
flux densities. The [CII] luminosity function is constrained in the range
~10^(7-9) (Lo) from both the 1/V_max and a maximum likelihood methods. The
shape of our derived [CII] emission line luminosity function agrees well with
the IR luminosity function. For the CO(1-0) and [CII] luminosity functions to
agree, we propose a varying ratio of [CII]/CO(1-0) as a function of CO
luminosity, with larger ratios for fainter CO luminosities. Limited [CII] high
redshift observations as well as estimates based on the IR and UV luminosity
functions are suggestive of an evolution in the [CII] luminosity function
similar to the evolution trend of the cosmic star formation rate density. Deep
surveys using ALMA with full capability will be able to confirm this
prediction.


title: Dyonic black holes and dilaton charge in string theory

abstract:
  We present the four-dimensional non-extremal dyonic black hole solution for
Einstein-Maxwell-dilaton theory in absence of a scalar potential written in
terms of integration constants only. These integration constants must satisfy a
set of conditions imposed by the equations of motion. By defining a posteriori
the mass $M$ of the black hole and the dilaton charge $\Sigma$, we show how to
recover the dyonic black hole solution found by Kallosh et.al. In particular,
our analysis show that there is a possibility in defining whether the dilaton
charge or the mass of the black hole is an independent parameter. When the mass
of the black hole is the independent parameter, then there is a well-defined
limit in which the dilaton charge is zero. For this case, it is straightforward
to provide an answer to why is $\phi_{H, \text{extreme}}$ independent of
$\phi_{0}$ and to why $\phi_{H, \text{extreme}}=\phi_{0}$ when the dilaton
charge is zero.


title: Are fast radio bursts the birthmark of magnetars?

abstract:
  A model of fast radio bursts, which enlists young, short period extragalactic
magnetars satisfying $B/P > 2 \times 10^{16}$~G~s$^{-1}$ (1~G =
1~statvolt~cm$^{-1}$) as the source, is proposed. When the parallel component
$\bE_\parallel$ of the surface electric field (under the scenario of a vacuum
magnetosphere) of such pulsars approaches 5 \% of the critical field $E_c =
m_e^2 c^3/(e\hbar)$, in strength, the field can readily decay via the Schwinger
mechanism into electron-positron pairs, the back reaction of which causes
$\bE_\parallel$ to oscillate on a characteristic timescale smaller than the
development of a spark gap. Thus, under this scenario, the open field line
region of the pulsar magnetosphere is controlled by Schwinger pairs, and their
large creation and acceleration rates enable the escaping pairs to coherently
emit radio waves directly from the polar cap. The majority of the energy is
emitted at frequencies $\lesssim 1$~GHz where the coherent radiation has the
highest yield, at a rate large enough to cause the magnetar to lose spin
significantly over timescale $\ap$ a few $\times 10^{-3}$~s, the duration of a
fast radio burst. Owing to circumstellar environment of a young magnetar,
however, the $\lesssim 1$~GHz radiation is likely to be absorbed or reflected
by the overlying matter. It is shown that the brightness of the remaining
(observable) frequencies of $\ap 1$~GHz and above are on par with a typical
fast radio burst. Unless some spin-up mechanism is available to recover the
original high rotation rate that triggered the Schwinger mechanism, the fast
radio burst will not be repeated again in the same magnetar.


title:
The size-frequency distribution of H>13 NEOs and ARM targets detected by
  Pan-STARRS1

abstract:
  We determine the absolute magnitude (H) distribution (or size-frequency
distribution, SFD; $N(H) \propto 10^{\alpha H}$ where $\alpha$ is the slope of
the distribution) for near-Earth objects (NEO) with $13<H<30$ and Asteroid
Retrieval Mission (ARM) targets with $27<H<31$ that were detected by the 1\st\
telescope of the Panoramic Survey Telescope and Rapid Response System -
Pan-STARRS1 (e.g. Kaiser et al. 2002, Kaiser 2004, Hodapp et al. 2004). The NEO
and ARM target detection efficiencies were calculated using the Greenstreet et
al. (2012) NEO orbit distribution. The debiased Pan-STARRS1 NEO absolute
magnitude distribution is more complex than a single slope power law - it shows
two transitions - at H$\sim$16 from steep to shallow slope, and in the
$21<H<23$ interval from a shallow to steep slope, which is consistent with
other recent works (e.g. Mainzer et al. 2011c, Brown et al. 2013, Harris and
D`Abramo 2015). We fit $\alpha = 0.48\pm0.02$ for NEOs with $13<H<16$, $\alpha
= 0.33\pm0.01$ for NEOs with $16<H<22$, and $\alpha = 0.62\pm0.03$ for the
smaller objects with $H>22$. There is also another change in slope from steep
to shallow around H=27. The three ARM target candidates detected by Pan-STARRS1
in one year of surveying have a corrected SFD with slope $\alpha =
0.40^{+0.33}_{-0.45}$.
  We also show that the window for follow up observations of small
(H$\gtrsim$22) NEOs with the NASA IRTF telescope and Arecibo and Goldstone
radars are extremely short - on order of days, and procedures for fast response
must be implemented in order to measure physical characteristics of small
Earth-approaching objects. CFHT's MegaCam and Pan-STARRS1 have longer observing
windows and are capable of following-up more NEOs due to their deeper limiting
magnitudes and wider fields of view.


title: Gravity Degrees of Freedom on a Null Surface

abstract:
  A canonical analysis for general relativity is performed on a null surface
without fixing the diffeomorphism gauge, and the canonical pairs of
configuration and momentum variables are derived. Next to the well-known spin-2
pair, also spin-1 and spin-0 pairs are identified. The boundary action for a
null boundary segment of spacetime is obtained, including terms on codimension
two corners.


title:
Lattice, Charge and Spin phase inhomogeneity in complex striped quantum
  matter

abstract:
  The Superstripes 2016 conference, held on June 23-29, 2016 in the island of
Ischia in Italy celebrated the 20th anniversary of this series of conferences.
For 20 years structural, electronic, and magnetic phase inhomogeneities in
quantum matter have been the scientific focus for a growing physics community
interested in complexity in quantum matter. It has been the meeting point for
different scientific communities facing the challenging project to unveil the
complex space and time landscapes in quantum matter. The interesting spatial
inhomogeneity length scale of multiple coexisting phase ranges from atomic to
mesoscopic and the time fluctuations are spread over multiple time scales. The
response of these materials changes using different experimental techniques
with different spatial and time resolution probing different aspects of the
quantum complexity.


title: M-theory Potential from the $G_2$ Hitchin Functional in Superspace

abstract:
  We embed the component fields of eleven-dimensional supergravity into a
superspace of the form $X\times Y$ where $X$ is the standard 4D, $N=1$
superspace and $Y$ is a smooth 7-manifold. The eleven-dimensional 3-form gives
rise to a tensor hierarchy of superfields gauged by the diffeomorphisms of $Y$.
It contains a natural candidate for a $G_2$ structure on $Y$, and being a
complex of superforms, defines a superspace Chern-Simons invariant. Adding to
this a natural generalization of the Riemannian volume on $X\times Y$ and
freezing the (superspin-$\frac32$ and 1) supergravity fields on $X$, we obtain
an approximation to the eleven-dimensional supergravity action that suffices to
compute the scalar potential. In this approximation the action is the sum of
the superspace Chern-Simons term and a superspace generalization of the Hitchin
functional for $Y$ as a $G_2$-structure manifold. Integrating out auxiliary
fields, we obtain the conditions for unbroken supersymmetry and the scalar
potential. The latter reproduces the Einstein-Hilbert term on $Y$ in a form due
to Bryant.


title: A Brief Survey of Non-Residue Based Computational Error Correction

abstract:
  The idea of computational error correction has been around for over half a
century. The motivation has largely been to mitigate unreliable devices,
manufacturing defects or harsh environments, primarily as a mandatory measure
to preserve reliability, or more recently, as a means to lower energy by
allowing soft errors to occasionally creep. While residue codes have shown
great promise for this purpose, there have been several orthogonal non-residue
based techniques. In this article, we provide a high level outline of some of
these non-residual approaches.


title: Cosmic infinity: A dynamical system approach

abstract:
  Dynamical system techniques are extremely useful to study cosmology. It turns
out that in most of the cases, we deal with finite isolated fixed points
corresponding to a given cosmological epoch. However, it is equally important
to analyse the asymptotic behaviour of the universe. On this paper, we show how
this can be carried out for 3-forms model. In fact, we show that there are
fixed points at infinity mainly by introducing appropriate compactifications
and defining a new time variable that washes away any potential divergence of
the system. The richness of 3-form models allows us as well to identify
normally hyperbolic non-isolated fixed points.


title: Shortening Anomalies in Supersymmetric Theories

abstract:
  We present new anomalies in two-dimensional ${\mathcal N} =(2, 2)$
superconformal theories. They obstruct the shortening conditions of chiral and
twisted chiral multiplets at coincident points. This implies that marginal
couplings cannot be promoted to background superfields in short
representations. Therefore, standard results that follow from ${\mathcal N}
=(2, 2)$ spurion analysis are invalidated. These anomalies appear only if
supersymmetry is enhanced beyond ${\mathcal N} =(2, 2)$. These anomalies
explain why the conformal manifolds of the K3 and $T^4$ sigma models are not
K\"ahler and do not factorize into chiral and twisted chiral moduli spaces and
why there are no ${\mathcal N} =(2, 2)$ gauged linear sigma models that cover
these conformal manifolds. We also present these results from the point of view
of the Riemann curvature of conformal manifolds.


title: The MuPix Telescope: A Thin, high Rate Tracking Telescope

abstract:
  The MuPix Telescope is a particle tracking telescope, optimized for tracking
low momentum particles and high rates. It is based on the novel High-Voltage
Monolithic Active Pixel Sensors (HV-MAPS), designed for the Mu3e tracking
detector. The telescope represents a first application of the HV-MAPS
technology and also serves as test bed of the Mu3e readout chain. The telescope
consists of up to eight layers of the newest prototypes, the MuPix7 sensors,
which send data self-triggered via fast serial links to FPGAs, where the data
is time-ordered and sent to the PC. A particle hit rate of 1 MHz per layer
could be processed. Online tracking is performed with a subset of the incoming
data. The general concept of the telescope, chip architecture, readout concept
and online reconstruction are described. The performance of the sensor and of
the telescope during test beam measurements are presented.


title: An introduction to matrix convex sets and free spectrahedra

abstract:
  The purpose of this paper is to give a self-contained overview of the theory
of matrix convex sets and free spectrahedra. We will give new proofs and
generalizations of key theorems. However we will also introduce various new
concepts and results as well. Key contributions of this paper are:
  - A new general Krein-Milman theorem that characterizes the smallest operator
tuple defining a compact matrix convex set.
  - The introduction and a characterization of matrix exposed points.
  - A (weak) Minkowski theorem in the language of matrix extreme points (with a
new proof of the weak Krein-Milman theorem of Webster and Winkler).
  - Simplified/new proofs of the Gleichstellensatz, Helton and McCulloughs
characterization of free spectrahedra as closures of matrix convex "free basic
open semialgebraic" sets and a characterization of hermitian irreducible free
loci of Helton, Klep and Vol$\check{\text{c}}$i$\check{\text{c}}$.


title:
Dispersion peculiarities of hybrid modes in a circular waveguide filled
  by a composite gyroelectromagnetic medium

abstract:
  Extraordinary dispersion features of a circular waveguide filled by a
longitudinally magnetized composite gyroelectromagnetic medium are studied. The
composite medium is considered to be constructed by juxtaposition together of
magnetic and semiconductor layers providing all characteristic dimensions of
the resulting multilayered system are much smaller than the wavelength in the
corresponding part of the composite medium. The waveguide dispersion equation
and its eigenmodes are derived. The mode classification is made in a standard
manner so that the guided modes are sorted into a class of hybrid HE and EH
waves in terms of their unique dispersion characteristics. The numerical
results are obtained in the band near the frequencies of corresponding
resonances in constitutive materials of the composite medium, and they show
that the modes behaviors become to be quite diverse due to manifestation of a
strong combined geometrical and material dispersion related to the waveguide
parameters and gyroelectromagnetic filling, respectively.


title:
Formation Control for Multi-Agent Systems with Connectivity Preservation
  and Event-Triggered Controllers

abstract:
  In this paper, event-triggered controllers and corresponding algorithms are
proposed to establish the formation with connectivity preservation for
multi-agent systems. Each agent needs to update its control input and to
broadcast this control input together with the relative state information to
its neighbors at its own triggering times, and to receive information at its
neighbors' triggering times. Two types of system dynamics, single integrators
and double integrators, are considered. As a result, all agents converge to the
formation exponentially with connectivity preservation, and Zeno behavior can
be excluded. Numerical simulations show the effectiveness of the theoretical
results.


title:
Bandwidth and Offset Launch Investigations on a 1.4 m Multimode Polymer
  Spiral Waveguide

abstract:
  Bandwidth measurements are conducted on a 1.4 m long spiral polymer multimode
waveguide for a SMF and 50/125 um MMF launch and for different input offsets.
The waveguide exhibits a bandwidth of at least 30 GHz for all input types,
yielding a bandwidth-length product of at least 42 GHzxm, while no impact is
observed on the waveguide performance due to the different spatial input
offsets. The results indicate that data transmission at data rates even higher
than 25 Gb/s can be achieved over such structures, thereby demonstrating the
potential of multimode polymer waveguide technologies in short-reach
board-level datacommunication links.


title:
Dispersion Studies on Multimode Polymer Spiral Waveguides for
  Board-Level Optical Interconnects

abstract:
  Dispersion studies are conducted on 1m long multimode polymer spiral
waveguides with different refractive index profiles. Bandwidth-length products
>40GHzxm are obtained from such waveguides under a 50/125 um MMF, indicating
the potential of this technology.


title: Maxwell's Equations in Media and Their Solution

abstract:
  A modified Faraday's law of electromagnetic induction in media is put
forward.


title:
Energy-efficient Machine Learning in Silicon: A Communications-inspired
  Approach

abstract:
  This position paper advocates a communications-inspired approach to the
design of machine learning systems on energy-constrained embedded `always-on'
platforms. The communications-inspired approach has two versions - 1) a
deterministic version where existing low-power communication IC design methods
are repurposed, and 2) a stochastic version referred to as Shannon-inspired
statistical information processing employing information-based metrics,
statistical error compensation (SEC), and retraining-based methods to implement
ML systems on stochastic circuit/device fabrics operating at the limits of
energy-efficiency. The communications-inspired approach has the potential to
fully leverage the opportunities afforded by ML algorithms and applications in
order to address the challenges inherent in their deployment on
energy-constrained platforms.


title: Asynchronous ADRs: Overnight vs Intraday Returns and Trading Strategies

abstract:
  American Depositary Receipts (ADRs) are exchange-traded certificates that
rep- resent shares of non-U.S. company securities. They are major financial
instruments for investing in foreign companies. Focusing on Asian ADRs in the
context of asyn- chronous markets, we present methodologies and results of
empirical analysis of their returns. In particular, we dissect their returns
into intraday and overnight com- ponents with respect to the U.S. market hours.
The return difference between the S&P500 index, traded through the SPDR S&P500
ETF (SPY), and each ADR is found to be a mean-reverting time series, and is
fitted to an Ornstein-Uhlenbeck process via maximum-likelihood estimation
(MLE). Our empirical observations also lead us to develop and backtest pairs
trading strategies to exploit the mean-reverting ADR-SPY spreads. We find
consistent positive payoffs when long position in ADR and short position in SPY
are simultaneously executed at selected entry and exit levels.


title: Non-Abelian Vortex in Four Dimensions as a Critical Superstring

abstract:
  We discuss recent progress in describing a certain non-Abelian vortex string
as a critical superstring on a conifold and clarify some subtle points. This
particular solitonic vortex is supported in four-dimensional N=2 supersymmetric
QCD with the U(2) gauge group, N_f=4 quark flavors and the Fayet-Iliopoulos
term. Under certain conditions the non-Abelian vortex can become infinitely
thin and can be interpreted as a critical ten-dimensional superstring. In
addition to four translational moduli the non-Abelian vortex under
consideration carries six orientational and size moduli. The vortex moduli
dynamics are described by a two-dimensional sigma model with the target space
{R}^4\times Y_6 where Y_6 is a non-compact Calabi-Yau conifold. The closed
string states which emerge in four dimensions (4D) are identified with hadrons
of 4D bulk N=2 QCD. It turns out that most of the states arising from the
ten-dimensional graviton spectrum are non-dynamical in 4D. A single dynamical
massless hypermultiplet associated with the deformation of the complex
structure of the conifold is found. It is interpreted as a monopole-monopole
baryon of the 4D theory (at strong coupling).


title:
Multiple imputation of multilevel missing data: An introduction to the R
  package pan

abstract:
  The treatment of missing data can be difficult in multilevel research because
state-of-the-art procedures such as multiple imputation (MI) may require
advanced statistical knowledge or a high degree of familiarity with certain
statistical software. In the missing data literature, pan has been recommended
for MI of multilevel data. In this article, we provide an introduction to MI of
multilevel missing data using the R package pan, and we discuss its
possibilities and limitations in accommodating typical questions in multilevel
research. In order to make pan more accessible to applied researchers, we make
use of the mitml package, which provides a user-friendly interface to the pan
package and several tools for managing and analyzing multiply imputed data
sets. We illustrate the use of pan and mitml with two empirical examples that
represent common applications of multilevel models, and we discuss how these
procedures may be used in conjunction with other software.


title:
Evaluating the Effect of Centralization on Routing Convergence on a
  Hybrid BGP-SDN Emulation Framework

abstract:
  A lot of applications depend on reliable and stable Internet connectivity.
These characteristics are crucial for mission-critical services such as
telemedical applications. An important factor that can affect connection
availability is the convergence time of BGP, the de-facto inter-domain routing
(IDR) protocol in the Internet. After a routing change, it may take several
minutes until the network converges and BGP routing becomes stable again.
Kotronis et al propose a novel Internet routing approach based on SDN
principles that combines several Autonomous Systems (AS) into groups, called
clusters, and introduces a logically centralized routing decision process for
the cluster participants. One of the goals of this concept is to stabilize the
IDR system and bring down its convergence time. However, testing whether such
approaches can improve on BGP problems requires hybrid SDN and BGP
experimentation tools that can emulate multiple ASes. Presently, there is a
lack of an easy to use public tool for this purpose. This work fills this gap
by building a suitable emulation framework and evaluating the effect that a
proof-of-concept IDR controller has on IDR convergence time.


title:
On Fell bundles over inverse semigroups and their left regular
  representations

abstract:
  We prove a version of Wordingham's theorem for left regular representations
in the setting of Fell bundles of inverse semigroups and use this result to
discuss the various associated cross sectional C*-algebras.


title: Numerical integral of resistance coefficients in diffusion

abstract:
  The resistance coefficients in screen Coulomb potential of stellar plasma are
evaluated in high accuracy. I have analyzed the possible singularities in the
integral of scattering angle. There are possible singularities in the case of
attractive potential. This may result in problem for numerical integral. In
order to avoid the problem, I have used a proper scheme, e.g., splitting into
many subintervals and the width of each subinterval is determined by the
variation of the integrand, to calculate the scattering angle. The collision
integrals are calculated by using Romberg's method therefore the accuracy is
high (i.e., $ \sim 10^{-12}$). The results of collision integrals and their
derivatives in $-12 \leq \psi \leq 5$ are listed. By using Hermite polynomial
interpolation from those data, the collision integrals can be obtained with an
accuracy of $10^{-10}$. For very weak coupled plasma ($\psi \geq 4.5$),
analytical fittings for collision integrals are available with an accuracy of
$10^{-11}$. I have compared the final results of resistance coefficients with
other works and found that, for repulsive potential, the results are basically
same to others, for attractive potential, the results in intermediate and
strong coupled case show significant differences. The resulting resistance
coefficients are tested in the solar model. Comparing with the widely used Cox
et al.(1989) and Thoul et al. (1994) models, the resistance coefficients in
screen Coulomb potential leads to a little weaker effect in solar model, which
is contrary to the expectation of attempts to solve the solar abundance
problem.


title:
R\'enyi Entropy for a $\bf 2d$ CFT with a gauge field: $\bf \widehat{\rm
  SU}(N)_1$ WZW theory on a branched torus

abstract:
  The R\'enyi entropy for the $\widehat{\rm SU}(N)_1$ WZW model as described by
$N$ free fermions coupled to a $U(1)$ constraint field is computed on an
$n$-sheeted branched torus. The boundary condition of the harmonic component of
the gauge field on the homology cycles of the genus $g$ Riemann surface is
central to the final result. This calculation is complementary to that of
arXiv:$1510.05993$, which presents the bose side of the bose-fermi equivalence.


title: Partial Integrability of Almost Complex Structures on Thurston Manifolds

abstract:
  We prove that any left-invariant symplectic almost complex structure on a
Thurston manifold which is compatible with its canonical left-invariant
Riemannian metric has holomorphic type 1.


title:
Minimum vertex degree condition for tight Hamiltonian cycles in
  3-uniform hypergraphs

abstract:
  We show that every 3-uniform hypergraph with $n$ vertices and minimum vertex
degree at least $(5/9+o(1))\binom{n}2$ contains a tight Hamiltonian cycle.
Known lower bound constructions show that this degree condition is
asymptotically optimal.


title:
Mouse T cell repertoires as statistical ensembles: overall
  characterization and age dependence

abstract:
  The ability of the adaptive immune system to respond to arbitrary pathogens
stems from the broad diversity of immune cell surface receptors (TCRs). This
diversity originates in a stochastic DNA editing process (VDJ recombination)
that acts each time a new immune cell is created from a stem cell. By analyzing
T cell sequence repertoires taken from the blood and thymus of mice of
different ages, we quantify the significant changes in this process that occur
in development from embryo to young adult. We find a rapid increase with age in
the number of random insertions in the VDJ recombination process, leading to a
dramatic increase in diversity. Since the blood accumulates thymic output over
time, blood repertoires are mixtures of different statistical recombination
processes and, by unraveling the mixture statistics, we can obtain a clear
picture of the time evolution of the early immune system. Sequence repertoire
analysis also allows us to detect the effect of selection on the output of the
VDJ recombination process. The effects we find are nearly identical between
thymus and blood, suggesting that they mainly reflect selection for proper
folding of the TCR receptor protein.


title: Plasmonics for emerging quantum technologies

abstract:
  Expanding the frontiers of information processing technologies and, in
particular, computing with ever increasing speed and capacity has long been
recognized an important societal challenge, calling for the development of the
next generation of quantum technologies. With its potential to exponentially
increase computing power, quantum computing opens up possibilities to carry out
calculations that ordinary computers could not finish in the lifetime of the
Universe, while optical communications based on quantum cryptography become
completely secure. At the same time, the emergence of Big Data and the ever
increasing demands of miniaturization and energy saving technologies bring
about additional fundamental problems and technological challenges to be
addressed in scientific disciplines dealing with light-matter interactions. In
this context, quantum plasmonics represents one of the most promising and
fundamental research directions and, indeed, the only one that enables ultimate
miniaturization of photonic components for quantum optics when being taken to
extreme limits in light-matter interactions.


title:
Kinetic Monte Carlo simulations of GaN homoepitaxy on c- and m-plane
  surfaces

abstract:
  The surface orientation can have profound effects on the atomic-scale
processes of crystal growth, and is essential to such technologies as GaN-based
light-emitting diodes and high-power electronics. We investigate the dependence
of homoepitaxial growth mechanisms on the surface orientation of a hexagonal
crystal using kinetic Monte Carlo simulations. To model GaN metal-organic vapor
phase epitaxy, in which N species are supplied in excess, only Ga atoms on a
hexagonal close-packed (HCP) lattice are considered. The results are thus
potentially applicable to any HCP material. Growth behaviors on c-plane ${(0 0
0 1)}$ and m-plane ${(0 1 \overline{1} 0)}$ surfaces are compared. We present a
reciprocal space analysis of the surface morphology, which allows extraction of
growth mode boundaries and direct comparison with surface X-ray diffraction
experiments. For each orientation we map the boundaries between 3-dimensional,
layer-by-layer, and step flow growth modes as a function of temperature and
growth rate. Two models for surface diffusion are used, which produce different
effective Ehrlich-Schwoebel step-edge barriers, and different adatom diffusion
anisotropies on m-plane surfaces. Simulation results in agreement with observed
GaN island morphologies and growth mode boundaries are obtained. These indicate
that anisotropy of step edge energy, rather than adatom diffusion, is
responsible for the elongated islands observed on m-plane surfaces. Island
nucleation spacing obeys a power-law dependence on growth rate, with exponents
of -0.24 and -0.29 for m- and c-plane, respectively.


title:
Sea of Majorana fermions from pseudo-scalar superconducting order in
  three dimensional Dirac materials

abstract:
  We find that singlet superconducting pairing can lead to Majorana fermions in
three dimensional Dirac superconductors (3DDS) if the pairing order parameter
is a pseudo-scalar, i.e. it changes sign under mirror reflection. The
pseudo-scalar superconducting order parameter, $\Delta_5$ can close and reopen
the spectral gap caused by the scalar Dirac mass $m$ in a three-dimensional
Dirac material (3DDM), giving rise to a two-dimensional Majorana sea (2DMS) at
the plane of the gap kink. By bringing the Hamiltonian into a canonical form
which then gives the winding number, we show that this system belongs to the
DIII class of topological superconductors. We calculate the transport signature
of 2DMS, namely a perfect Andreev-Klein transmission that manifests in a robust
peak in the differential conductance. Further, we find the $4\pi$ periodicity
in the $\Delta_5|m|\Delta_5$ Josephson junc- tions. Gauge transformed version
of the present scenario implies that the interface of a conventional s-wave
superconductor with a peculiar 3DDM whose mass is a pseudo-scalar, m5 also
hosts a 2DMS.


title:
Nonlinear Frequency Shift in Raman Backscattering and its Implications
  for Plasma Diagnostics

abstract:
  Raman backscattered radiation of intense laser pulses in plasma is
investigated for a wide range of intensities relevant to laser wakefield
acceleration. The weakly nonlinear dispersion relation for Raman backscattering
predicts an intensity and density dependent frequency shift that is opposite to
that suggested by a simple relativistic consideration. This observation has
been benchmarked against experimental results, providing a novel diagnostic for
laser-plasma interactions.


title: Quasi-atomic three- and four-body systems with muonium

abstract:
  Properties of some few-body systems which include one positively charged muon
$\mu^{+}$ and two electrons $e^{-}$ are discussed. In particular, we consider
the negatively charged muonium ion Mu$^{-}$ (or $\mu^{+} e^{-}_{2}$) and
four-body MuPs (or $\mu^{+} e^{-}_{2} e^{+}$) systems each of which has only
one stable bound (ground) state. The problem of annihilation of the
electron-positron pair(s) in the MuPs system is investigated. The hyperfine
structure splitting of the ground state in the MuPs system evaluated with our
expectation value of the muon-positron delta-function is $\Delta \approx$
23.05758 $MHz$. Another group of interesting four-body neutral systems
investigated in this study includes the $p^{+} \mu^{+} e^{-}_2, d^{+} \mu^{+}
e^{-}_2$ and $t^{+} \mu^{+} e^{-}_2$ `quasi-molecules'. These quasi-molecules
are formed in large numbers when positively charged muons slow down in liquid
hydrogen, or in liquid deuterium and/or tritium. The properties of these
systems are unique, since they occupy an intermediate position between actual
two-center molecules and one-center atoms.


title: A Modular Theory of Feature Learning

abstract:
  Learning representations of data, and in particular learning features for a
subsequent prediction task, has been a fruitful area of research delivering
impressive empirical results in recent years. However, relatively little is
understood about what makes a representation `good'. We propose the idea of a
risk gap induced by representation learning for a given prediction context,
which measures the difference in the risk of some learner using the learned
features as compared to the original inputs. We describe a set of sufficient
conditions for unsupervised representation learning to provide a benefit, as
measured by this risk gap. These conditions decompose the problem of when
representation learning works into its constituent parts, which can be
separately evaluated using an unlabeled sample, suitable domain-specific
assumptions about the joint distribution, and analysis of the feature learner
and subsequent supervised learner. We provide two examples of such conditions
in the context of specific properties of the unlabeled distribution, namely
when the data lies close to a low-dimensional manifold and when it forms
clusters. We compare our approach to a recently proposed analysis of
semi-supervised learning.


title:
On the hyperfine structure of the triplet $n^{3}S-$states of the
  four-electron atoms and ions

abstract:
  Hyperfine structures of the triplet $n^3S-$states in the four-electron
Be-atom(s) and Be-like ions are considered. It is shown that to determine the
hyperfine structure splitting in such atomic systems one needs to know the
triplet electron density at the central atomic nucleus $\rho_T(0)$. We have
developed the procedure which allows allows one to determine such an electron
density $\rho_T(0)$ for arbitrary four-electron atoms and ions.


title:
Thermalization of noninteracting quantum systems coupled to blackbody
  radiation: A Lindblad-based analysis

abstract:
  We study the thermalization of an ensemble of $N$ elementary,
arbitrarily-complex, quantum systems, mutually noninteracting but coupled as
electric or magnetic dipoles to a blackbody radiation. The elementary systems
can be all the same or belong to different species, distinguishable or
indistinguishable, located at fixed positions or having translational degrees
of freedom. Even if the energy spectra of the constituent systems are
nondegenerate, as we suppose, the ensemble unavoidably presents degeneracies of
the energy levels and/or of the energy gaps. We show that, due to these
degeneracies, a thermalization analysis performed by the popular quantum
optical master equation reveals a number of serious pathologies, possibly
including a lack of ergodicity. On the other hand, a consistent thermalization
scenario is obtained by introducing a Lindblad-based approach, in which the
Lindblad operators, instead of being derived from a microscopic calculation,
are established as the elements of an operatorial basis with squared amplitudes
fixed by imposing a detailed balance condition and requiring their
correspondence with the dipole transition rates evaluated under the first-order
perturbation theory. Due to the above-mentioned degeneracies, this procedure
suffers a basis arbitrariness which, however, can be removed by exploiting the
fact that the thermalization of an ensemble of noninteracting systems cannot
depend on the ensemble size. As a result, we provide a clear-cut partitioning
of the thermalization time into dissipation and decoherence times, for which we
derive formulas giving the dependence on the energy levels of the elementary
systems, the size $N$ of the ensemble, and the temperature of the blackbody
radiation.

categories: quant-ph cond-mat.stat-mech math-ph math.MP


title:
Disentangling Hot Jupiters formation location from their chemical
  composition

abstract:
  We use a population synthesis model that includes pebbles and gas accretion,
planetary migration, and a simplified chemistry scheme to study the formation
of hot-Jupiters. Models have been proposed that these planets can either
originate beyond the snowline and then move inward via disk migration, or form
"in-situ" inside the snowline. The goal of this work is to verify which of
these two scenarios is more compatible with pebble accretion, and whether we
can distinguish observationally between them via the resulting planetary C/O
ratios and core masses. Our results show that, for solar system composition,
the C/O ratios will vary but moderately between the two populations, since a
significant amount of carbon and oxygen are locked up in refractories. In this
case, we find a strong correlation between the carbon and oxygen abundances and
core mass. The C/O ratio variations are more pronounced in the case where we
assume that all carbon and oxygen are in volatiles. On average, Hot-Jupiters
forming "in-situ" inside the snowline will have higher C/O ratios because they
accrete less water ice. However, only Hot-Jupiters forming in-situ around stars
with C/O=0.8 can have a C/O ratio higher than unity. We finally find that, even
with fast pebble accretion, it is significantly easier to form Hot-Jupiters
outside of the snowline, even if forming these "in-situ" is not impossible in
the limit of the simplifying assumptions made.


title: Regular bipartite graphs and intersecting families

abstract:
  In this paper we present a simple unifying approach to prove several
statements about intersecting and cross-intersecting families, including the
Erd\H os--Ko--Rado theorem, the Hilton--Milner theorem, a theorem due to Frankl
concerning the size of intersecting families with bounded maximal degree, and
versions of results on the sum of sizes of non-empty cross-intersecting
families due to Frankl and Tokushige. Several new stronger results are also
obtained.
  Our approach is based on the use of regular bipartite graphs. These graphs
are quite often used in Extremal Set Theory problems, however, the approach we
develop proves to be particularly fruitful.


title:
Computationally Efficient Target Classification in Multispectral Image
  Data with Deep Neural Networks

abstract:
  Detecting and classifying targets in video streams from surveillance cameras
is a cumbersome, error-prone and expensive task. Often, the incurred costs are
prohibitive for real-time monitoring. This leads to data being stored locally
or transmitted to a central storage site for post-incident examination. The
required communication links and archiving of the video data are still
expensive and this setup excludes preemptive actions to respond to imminent
threats. An effective way to overcome these limitations is to build a smart
camera that transmits alerts when relevant video sequences are detected. Deep
neural networks (DNNs) have come to outperform humans in visual classifications
tasks. The concept of DNNs and Convolutional Networks (ConvNets) can easily be
extended to make use of higher-dimensional input data such as multispectral
data. We explore this opportunity in terms of achievable accuracy and required
computational effort. To analyze the precision of DNNs for scene labeling in an
urban surveillance scenario we have created a dataset with 8 classes obtained
in a field experiment. We combine an RGB camera with a 25-channel VIS-NIR
snapshot sensor to assess the potential of multispectral image data for target
classification. We evaluate several new DNNs, showing that the spectral
information fused together with the RGB frames can be used to improve the
accuracy of the system or to achieve similar accuracy with a 3x smaller
computation effort. We achieve a very high per-pixel accuracy of 99.1%. Even
for scarcely occurring, but particularly interesting classes, such as cars, 75%
of the pixels are labeled correctly with errors occurring only around the
border of the objects. This high accuracy was obtained with a training set of
only 30 labeled images, paving the way for fast adaptation to various
application scenarios.


title: Diverse Neural Network Learns True Target Functions

abstract:
  Neural networks are a powerful class of functions that can be trained with
simple gradient descent to achieve state-of-the-art performance on a variety of
applications. Despite their practical success, there is a paucity of results
that provide theoretical guarantees on why they are so effective. Lying in the
center of the problem is the difficulty of analyzing the non-convex loss
function with potentially numerous local minima and saddle points. Can neural
networks corresponding to the stationary points of the loss function learn the
true target function? If yes, what are the key factors contributing to such
nice optimization properties?
  In this paper, we answer these questions by analyzing one-hidden-layer neural
networks with ReLU activation, and show that despite the non-convexity, neural
networks with diverse units have no spurious local minima. We bypass the
non-convexity issue by directly analyzing the first order optimality condition,
and show that the loss can be made arbitrarily small if the minimum singular
value of the "extended feature matrix" is large enough. We make novel use of
techniques from kernel methods and geometric discrepancy, and identify a new
relation linking the smallest singular value to the spectrum of a kernel
function associated with the activation function and to the diversity of the
units. Our results also suggest a novel regularization function to promote unit
diversity for potentially better generalization.


title:
Control of bulk superconductivity in a BCS superconductor by surface
  charge doping via electrochemical gating

abstract:
  The electrochemical gating technique is a powerful tool to tune the
\textit{surface} electronic conduction properties of various materials by means
of pure charge doping, but its efficiency is thought to be hampered in
materials with a good electronic screening. We show that, if applied to a
metallic superconductor (NbN thin films), this approach allows observing
reversible enhancements or suppressions of the \emph{bulk} superconducting
transition temperature, which vary with the thickness of the films. These
results are interpreted in terms of proximity effect, and indicate that the
effective screening length depends on the induced charge density, becoming much
larger than that predicted by standard screening theory at very high electric
fields.


title: Introduction to "Standing together in Troubled Times"

abstract:
  This Introduction opens the book {\sl Standing Together in Troubled Times}
which presents a story of friendship between Wolfgang Pauli, one of the
greatest theoretical physicists of the 20th century, and Charlotte Houtermans.
They met at the very onset of the quantum era, in the late 1920s in Germany
where Charlotte was a physics student at G\"ottingen University. At that time
G\"ottingen was right at the heart of groundbreaking developments in physics.
Both Pauli and Houtermans personally knew major participants in the quantum
revolution. Caught between two evils -- German National Socialism and Soviet
Communism -- Charlotte Houtermans would have likely perished if it were not for
the brotherhood of physicists: Niels Bohr, Wolfgang Pauli, Albert Einstein,
James Franck, Max Born, Robert Oppenheimer and many other noted scientists who
tried to save friends and colleagues (either leftist sympathizers or Jews) who
were in mortal danger of becoming entrapped in a simmering pre-WWII Europe.
This book is based on newly discovered documents from the Houtermans family
archive, including Pauli's numerous letters to Houtermans, her correspondence
with other great physicists, her diaries, and interviews with her children.
Almost all documents presented in this book are being published for the first
time.


title: Using Ramsey's Theorem Once

abstract:
  We show that RT(2,4) cannot be proved with one typical application of RT(2,2)
in an intuitionistic extension of RCA0 to higher types, but that this does not
remain true when the law of the excluded middle is added. The argument uses
Kohlenbach's axiomatization of higher order reverse mathematics, results
related to modified reducibility, and a formalization of Weihrauch
reducibility.


title:
Local Elasticity in Nonlinear Rheology of Interacting Colloidal Glasses
  Revealed by Neutron Scattering and Rheometry

abstract:
  The flow of colloidal suspensions is ubiquitous in nature and industry.
Colloidal suspensions exhibit a wide range of rheological behavior, which
should be closely related to the microscopic structure of the systems. With
in-situ small-angle neutron scattering complemented by rheological
measurements, we investigated the deformation behavior of a charge-stabilized
colloidal glass at particle level undergoing steady shear. A short-lived,
localized elastic response at particle level, termed as transient elasticity
zone (TEZ), was identified from the neutron spectra. The existence of the TEZ
is a signature of the dynamical heterogeneity: The body of fluids under shear
behaves like an elastic solid within the spatial range of TEZ but like fluid
outside the TEZ. The size of TEZ shrinks as the shear rate increases in the
shear thinning region, which shows that the shear thinning is accompanied by a
diminishing dynamical heterogeneity. More interestingly, the TEZ is found to be
the structural unit that provides the resistance to the imposed shear, as
evidenced by the quantitative agreement between the local elastic stress
sustained by TEZ and the macroscopic stress from rheological measurements at
low and moderate shear rates. Besides the charged-stabilized colloidal
suspension, a hard-sphere colloidal suspension at the same volume fraction and
shear rates was also measured. The result highlights the key role of the
electrostatic interparticle repulsion in promoting the local elasticity. Our
findings provide an understanding on the nonlinear rheology of interacting
colloidal glasses from a micro-mechanical view.


title: Robust Solid State Quantum System Operating at 800 K

abstract:
  Realization of Quantum information and communications technologies requires
robust, stable solid state single photon sources. However, most existing
sources cease to function above cryogenic or room temperature due to thermal
ionization or strong phonon coupling which impede their emissive and quantum
properties. Here we present an efficient single photon source based on a defect
in a van der Waals crystal that is optically stable and operates at elevated
temperatures of up to 800 K. The quantum nature of the source and the photon
purity are maintained upon heating to 800 K and cooling back to room
temperature. Our report of a robust high temperature solid state single photon
source constitutes a significant step to-wards practical, integrated quantum
technologies for real-world environments.


title: A Periodic Table of Effective Field Theories

abstract:
  We systematically explore the space of scalar effective field theories (EFTs)
consistent with a Lorentz invariant and local S-matrix. To do so we define an
EFT classification based on four parameters characterizing 1) the number of
derivatives per interaction, 2) the soft properties of amplitudes, 3) the
leading valency of the interactions, and 4) the spacetime dimension. Carving
out the allowed space of EFTs, we prove that exceptional EFTs like the
non-linear sigma model, Dirac-Born-Infeld theory, and the special Galileon lie
precisely on the boundary of allowed theory space. Using on-shell momentum
shifts and recursion relations, we prove that EFTs with arbitrarily soft
behavior are forbidden and EFTs with leading valency much greater than the
spacetime dimension cannot have enhanced soft behavior. We then enumerate all
single scalar EFTs in d<6 and verify that they correspond to known theories in
the literature. Our results suggest that the exceptional theories are the
natural EFT analogs of gauge theory and gravity because they are one-parameter
theories whose interactions are strictly dictated by properties of the
S-matrix.


title:
Energy efficient and fast reversal of a fixed skyrmions with spin
  current assisted by voltage controlled magnetic anisotropy

abstract:
  Recent work [1,2] suggests that ferromagnetic reversal with spin transfer
torque (STT) requires more current in a system in the presence of DMI than
switching a typical ferromagnet of the same dimensions and perpendicular
magnetic anisotropy (PMA). However, DMI promotes stabilization of skyrmions and
we report that when the perpendicular anisotropy is modulated (reduced) for
both the skyrmion and ferromagnet, it takes much smaller current to reverse the
fixed skyrmion than to reverse the ferromagnet in the same time, or the
skyrmion reverses much faster than the ferromagnet at similar levels of
current. We show with rigorous micromagnetic simulations and energy portraits
that the skyrmion switching proceeds along a different path at very low PMA
which results in a significant reduction in the spin current required or time
required for reversal. This can have potential for memory application where a
relatively simple modification of the standard STT-RAM to include a heavy metal
adjacent to the soft magnetic layer and with appropriate design of the tunnel
barrier can lead to energy efficient and fast magnetic memory device based on
the reversal of fixed skyrmions.


title: Discovery of a transient gamma-ray counterpart to FRB 131104

abstract:
  We report our discovery in Swift satellite data of a transient gamma-ray
counterpart (3.2$\sigma$ confidence) to the fast radio burst FRB131104, the
first such counterpart to any FRB. The transient has duration $T_{90} \gtrsim
100$s and fluence $S_\gamma\approx 4\times 10^{-6}$ erg cm$^{-2}$, increasing
the energy budget for this event by more than a billion times; at the nominal
$z\approx 0.55$ redshift implied by its dispersion measure, the burst's
gamma-ray energy output is $E_\gamma \approx 5\times 10^{51}$ erg. The observed
radio to gamma-ray fluence ratio for FRB131104 is consistent with a lower limit
we derive from Swift observations of another FRB, which is not detected in
gamma-rays, and with an upper limit previously derived for the brightest
gamma-ray flare from SGR 1806-20, which was not detected in the radio. X-ray,
ultraviolet, and optical observations beginning two days after the FRB do not
reveal any associated afterglow, supernova, or transient; Swift observations
exclude association with the brightest 65% of Swift gamma-ray burst X-ray
afterglows, while leaving the possibility of an associated supernova at much
more than 10% the FRB's nominal distance, $D\gtrsim 320$ Mpc, largely
unconstrained. Transient high-luminosity gamma-ray emission arises most
naturally in a relativistic outflow or shock breakout, as for example from
magnetar flares, gamma-ray bursts, relativistic supernovae, and some types of
galactic nuclear activity. Our discovery thus bolsters the case for an
extragalactic origin for some FRBs and suggests that future rapid-response
observations might identify long-lived counterparts, resolving the nature of
these mysterious phenomena and realizing their promise as probes of cosmology
and fundamental physics.


title: Surface effects in nucleation

abstract:
  The classical nucleation theory (CNT) concept of a nucleus as a fragment of
the bulk new phase fails for nanosized nuclei. An extension of CNT taking into
account the properties of the transition region between coexisting bulk phases
is proposed. For this purpose, the finite-thickness layer method which is an
alternative to Gibbs one is used; the transition region is considered as a
separate (surface) phase. An equation for the nucleation work is derived which
is basic for the multivariable theory of nucleation. Equations of equilibrium
following from it are employed for considering the dependences of surface
tension on radius and temperature for droplets; Kelvin formula for the
equilibrium vapor pressure is extended to small radii. It is shown that the
ratio of the isothermal nucleation rate to that of CNT can achieve several
orders of magnitude due to the curvature effect (the dependence of surface
tension on curvature). The analysis of different dependences of the Tolman
length on radius, d(R), suggests that (i) the curvature effect is determined by
the value of d(0) which is positive and relates to the limiting (spinodal)
vapor supersaturation and (ii) the function d(R) decreases with increasing
radius; at the same time, this effect is weakly sensitive to the form of the
function d(R) and its asymptotic value. The second differential of the work is
obtained as a quadratic form with contributions from both the bulk and surface
phases. It is used for calculating the fluctuations of surface layer parameters
such as the surface tension and the specific surface area as well as the
fluctuations of nucleus parameters.


title:
Hitting Time and Convergence Rate Bounds for Symmetric Langevin
  Diffusions

abstract:
  We provide quantitative bounds on the convergence to stationarity of
real-valued Langevin diffusions with symmetric target densities.


title: Orbifolds and Exact Solutions of Strongly-Coupled Matrix Models

abstract:
  We find an exact solution to strongly-coupled matrix models with a
single-trace monomial potential. Our solution yields closed form expressions
for the partition function as well as averages of Schur functions. The results
are fully factorized into a product of terms linear in the rank of the matrix
and the parameters of the model. We extend our formulas to include both
logarthmic and finite-difference deformations, thereby generalizing the
celebrated Selberg and Kadell integrals. We conjecture a formula for
correlators of two Schur functions in these models, and explain how our results
follow from a general orbifold-like procedure that can be applied to any
one-matrix model with a single-trace potential.


title: Bloch oscillations: Inverse problem

abstract:
  We use a neural network approach to explore the inverse problem of Bloch
oscillations in a monoatomic linear chain: given a signal describing the path
of oscillations of electrons as a function of time, we determine the strength
of the applied field along the direction of motion or, equivalently, the
lattice spacing. We find that the proposed approach has more than 80% of
accuracy classifying the studied physical parameters.


title:
Therapeutic target discovery using Boolean network attractors:
  improvements of kali

abstract:
  In a previous article, an algorithm for identifying therapeutic targets in
Boolean networks modeling pathological mechanisms was introduced. In the
present article, the improvements made on this algorithm, named kali, are
described. These improvements are i) the possibility to work on asynchronous
Boolean networks, ii) a finer assessment of therapeutic targets and iii) the
possibility to use multivalued logic. kali assumes that the attractors of a
dynamical system, such as a Boolean network, are associated with the phenotypes
of the modeled biological system. Given a logic-based model of pathological
mechanisms, kali searches for therapeutic targets able to reduce the
reachability of the attractors associated with pathological phenotypes, thus
reducing their likeliness. kali is illustrated on an example network and used
on a biological case study. The case study is a published logic-based model of
bladder tumorigenesis from which kali returns consistent results. However, like
any computational tool, kali can predict but can not replace human expertise:
it is a supporting tool for coping with the complexity of biological systems in
the field of drug discovery.


title:
Experimental Evidence of Directivity-Enhancing Mechanisms in Nonlinear
  Lattices

abstract:
  In this letter, we experimentally investigate the directional characteristics
of propagating, finite-amplitude wave packets in lattice materials, with an
emphasis on the functionality enhancement due to the nonlinearly-generated
higher harmonics. To this end, we subject a thin, periodically perforated sheet
to out-of-plane harmonic excitations, and we design a systematic measurement
and data processing routine that leverages the full-wavefield reconstruction
capabilities of a laser vibrometer to precisely delineate the effects of
nonlinearity. We demonstrate experimentally that the interplay of dispersion,
nonlinearity, and modal complexity which is involved in the generation and
propagation of higher harmonics gives rise to secondary wave packets with
characteristics that conform to the dispersion relation of the corresponding
linear structure. Furthermore, these nonlinearly generated wave features
display modal and directional characteristics that are complementary to those
exhibited by the fundamental harmonic, thus resulting in an augmentation of the
functionality landscape of the lattice. These results provide proof of concept
for the possibility to engineer the nonlinear wave response of mechanical
metamaterials through a geometric and topological design of the unit cell.


title:
The Control of the False Discovery Rate in Fixed Sequence Multiple
  Testing

abstract:
  Controlling the false discovery rate (FDR) is a powerful approach to multiple
testing. In many applications, the tested hypotheses have an inherent
hierarchical structure. In this paper, we focus on the fixed sequence structure
where the testing order of the hypotheses has been strictly specified in
advance. We are motivated to study such a structure, since it is the most basic
of hierarchical structures, yet it is often seen in real applications such as
statistical process control and streaming data analysis. We first consider a
conventional fixed sequence method that stops testing once an acceptance
occurs, and develop such a method controlling the FDR under both arbitrary and
negative dependencies. The method under arbitrary dependency is shown to be
unimprovable without losing control of the FDR and unlike existing FDR methods;
it cannot be improved even by restricting to the usual positive regression
dependence on subset (PRDS) condition. To account for any potential mistakes in
the ordering of the tests, we extend the conventional fixed sequence method to
one that allows more but a given number of acceptances. Simulation studies show
that the proposed procedures can be powerful alternatives to existing FDR
controlling procedures. The proposed procedures are illustrated through a real
data set from a microarray experiment.


title: The gap of the area-weighted Motzkin spin chain is exponentially small

abstract:
  We prove that the energy gap of the model proposed by Zhang, Ahmadain, and
Klich [1] is exponentially small in the square of the system size. In [2] a
class of exactly solvable quantum spin chain models was proposed that have
integer spins ($s$), with a nearest neighbors Hamiltonian, and a unique ground
state. The ground state can be seen as a uniform superposition of all
$s-$colored Motzkin walks. The half-chain entanglement entropy provably
violates the area law by a square root factor in the system's size
($\sim\sqrt{n}$) for $s>1$. For $s=1$, the violation is logarithmic [3].
Moreover in [2] it was proved that the gap vanishes polynomially and is
$O(n^{-c})$ with $c\ge2$.
  Recently, a deformation of [2], which we call "weighted Motzkin quantum spin
chain" was proposed [1]. This model has a unique ground state that is a
superposition of the $s-$colored Motzkin walks weighted by
$t^{\text{area\{Motzkin walk\}}}$ with $t>1$. The most surprising feature of
this model is that it violates the area law by a factor of $n$. Here we prove
that the gap of this model is upper bounded by $8ns\text{ }t^{-n^{2}/3}$ for
$t>1$.

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


title: Understanding rheological hysteresis in soft glassy materials

abstract:
  Motivated by recent experimental studies of rheological hysteresis in soft
glassy materials, we study numerically strain rate sweeps in simple yield
stress fluids and viscosity bifurcating yield stress fluids. Our simulations of
downward followed by upward strain rate sweeps, performed within fluidity
models and the soft glassy rheology model, successfully capture the
experimentally observed monotonic decrease of the area of the rheological
hysteresis loop with sweep time in simple yield stress fluids, and the bell
shaped dependence of hysteresis loop area on sweep time in viscosity
bifurcating fluids. We provide arguments explaining these two different
functional forms in terms of differing tendencies of simple and viscosity
bifurcating fluids to form shear bands during the sweeps, and show that the
banding behaviour captured by our simulations indeed agrees with that reported
experimentally. We also discuss the difference in hysteresis behaviour between
inelastic and viscoelastic fluids. Our simulations qualitatively agree with the
experimental data discussed here for four different soft glassy materials.


title: Spectroscopic investigation of defects in two dimensional materials

abstract:
  Two-dimensional (2D) materials have been extensively studied in recent years
due to their unique properties and great potential for applications. Different
types of structural defects could present in 2D materials and have strong
influence on their properties. Optical spectroscopic techniques, e.g. Raman and
photoluminescence (PL) spectroscopy, have been widely used for defect
characterization in 2D materials. In this review, we briefly introduce
different types of defects and discuss their effects on the mechanical,
electrical, optical, thermal, and magnetic properties of 2D materials. Then, we
review the recent progress on Raman and PL spectroscopic investigation of
defects in 2D materials, i.e. identifying of the nature of defects and also
quantifying the numbers of defects. Finally, we highlight perspectives on
defect characterization and engineering in 2D materials.


title: Superintermolecular orbitals in the C$_{60}$/pentacene complex

abstract:
  We report a group of unusually big molecular orbitals in the C60/pentacene
complex. Our first-principles density functional calculation shows that these
orbitals are very delocalized and cover both C60 and pentacene, which we call
superintermolecular orbitals or SIMOs. Their spatial extension can reach 1 nm
or larger. Optically, SIMOs are dark. Different from ordinary unoccupied
molecular orbitals, SIMOs have a very weak Coulomb and exchange interaction.
Their energy levels are very similar to the native superatomic molecular
orbitals in C60, and can be approximately characterized by orbital angular
momentum quantum numbers. They have a distinctive spatial preference. These
features fit the key characters of charge-generation states that channel
initially-bound electrons and holes into free charge carriers. Thus, our
finding is important for C60/pentacene photovoltaics.


title:
Interfacial-state coupling induced topological phase transitions in SnTe
  (110) thin film

abstract:
  A defining feature of topological insulating phases is symmetry-protected
interfacial Dirac states. SnTe is a representative topological crystalline
insulator, of which (110) thin films have two symmetry-unrelated valleys of
interfacial states. With the help of valley-contrasting couplings of
interfacial states, we design various two-dimensional topological phases in
(110) SnTe thin film systems. Our first-principles calculations demonstrate
that surface-state coupling strengths of two valleys independently vary with
the thickness of the thin film, leading to both two-dimensional topological
crystalline insulator and quantum spin Hall insulator. Most interestingly, by
constructing a nanoribbon array of SnTe thin film, edge-state couplings of
nanoribbons can further induce topological phase transition between the above
topological phases with high tunability, which offers multi-mode quantum
transport with potential use in electronic and spintronic devices.


title: Quantum State Transmission in a Superconducting Charge Qubit-Atom Hybrid

abstract:
  Hybrids consisting of macroscopic superconducting circuits and microscopic
components, such as atoms and spins, have the potential of transmitting an
arbitrary state between different quantum species, leading to the prospective
of high-speed operation and long-time storage of quantum information. Here we
propose a novel hybrid structure, where a neutral-atom qubit directly
interfaces with a superconducting charge qubit, to implement the qubit-state
transmission. The highly-excited Rydberg atom located inside the gate capacitor
strongly affects the behavior of Cooper pairs in the box while the atom in the
ground state hardly interferes with the superconducting device. In addition,
the DC Stark shift of the atomic states significantly depends on the
charge-qubit states. By means of the standard spectroscopic techniques and
sweeping the gate voltage bias, we show how to transfer an arbitrary quantum
state from the superconducting device to the atom and vice versa.


title: Dispersion relation and surface gravity of universal horizons

abstract:
  In Einstein-aether theory, violating Lorentz invariance permits some
super-luminal communications, and the universal horizon can trap excitations
traveling at arbitrarily high velocities. To better understand the nature of
these universal horizons, we first modify the ray tracing method, and then use
it to study their surface gravity in charged Einstein-aether black hole
spacetime. Instead of the previous result in Ref. [Phys. Rev. D 89, 064061],
our results show that the surface gravity of the universal horizon is dependent
on the specific dispersion relation, $\kappa_{UH}=2(z-1)\kappa_{uh}/z$, where
$z$ denotes the power of the leading term in the superluminal dispersion
relation, characterizing different species of particles. And the associated
Hawking temperatures also are different with $z$. These findings, which
coincide with those in Ref. [Nucl. Phys. B 913, 694] derived by the tunneling
method, provide some full understanding of black hole thermodynamics in
Lorentz-violating theories.


title:
Laser-induced ultrafast demagnetization time and spin moment in
  ferromagnets: First-principles calculation

abstract:
  When a laser pulse excites a ferromagnet, its spin undergoes a dramatic
change. The initial demagnetization process is very fast. Experimentally, it is
found that the demagnetization time is related to the spin moment in the
sample. In this study, we employ the first-principles method to directly
simulate such a process. We use the fixed spin moment method to change the spin
moment in ferromagnetic nickel, and then we employ the Liouville equation to
couple the laser pulse to the system. We find that in general the dependence of
demagnetization time on the spin moment is nonlinear: It decreases with the
spin moment up to a point, after which an increase with the spin moment is
observed, followed by a second decrease. To understand this, we employ an
extended Heisenberg model, which includes both the exchange interaction and
spin-orbit coupling. The model directly links the demagnetization rate to the
spin moment itself and demonstrates analytically that the spin relaxes more
slowly with a small spin moment. A future experimental test of our predictions
is needed.


title: Adaptive Controls of FWER and FDR Under Block Dependence

abstract:
  Often in multiple testing, the hypotheses appear in non-overlapping blocks
with the associated $p$-values exhibiting dependence within but not between
blocks. We consider adapting the Benjamini-Hochberg method for controlling the
false discovery rate (FDR) and the Bonferroni method for controlling the
familywise error rate (FWER) to such dependence structure without losing their
ultimate controls over the FDR and FWER, respectively, in a non-asymptotic
setting. We present variants of conventional adaptive Benjamini-Hochberg and
Bonferroni methods with proofs of their respective controls over the FDR and
FWER. Numerical evidence is presented to show that these new adaptive methods
can capture the present dependence structure more effectively than the
corresponding conventional adaptive methods. This paper offers a solution to
the open problem of constructing adaptive FDR and FWER controlling methods
under dependence in a non-asymptotic setting and providing real improvements
over the corresponding non-adaptive ones.


title: Ultrafast reduction of exchange splitting in ferromagnetic nickel

abstract:
  A decade ago Rhie \et (Phys. Rev. Lett. {\bf 90}, 247201 (2003)) reported
that when ferromagnetic nickel is subject to an intense ultrashort laser pulse,
its exchange splitting is reduced quickly. But to simulate such reduction
remains a big challenge. The popular rigid band approximation (RBA), where both
the band structure and the exchange splitting are held fixed before and after
laser excitation, is unsuitable for this purpose, while the time-dependent
density functional theory could be time-consuming. To overcome these
difficulties, we propose a time-dependent Liouville and density functional
theory (TDLDFT) that integrates the time-dependent Liouville equation into the
density functional theory. As a result, the excited charge density is
reiterated back into the Kohn-Sham equation, and the band structure is allowed
to change dynamically. Even with the ground-state density functional, a larger
demagnetization than RBA is found; after we expand Ortenzi's spin scaling
method into an excited-state (laser) density functional, we find that the
exchange splitting is indeed strongly reduced, as seen in the experiment. Both
the majority and minority bands are shifted toward the Fermi level, but the
majority shifts a lot more. The ultrafast reduction in exchange splitting
occurs concomitantly with demagnetization. While our current theory is still
unable to yield the same percentage loss in the spin moment as observed in the
experiment, it predicts a correct trend that agrees with the experiments. With
a better functional, we believe that our results can be further improved.


title:
Analysis of the nonleptonic charmonium modes $B_s^0 \to J/\psi
  f_{2}^{\prime}(1525)$ and $B_s^0 \to J/\psi K^+K^-$

abstract:
  In this work, we present an analysis of the nonleptonic charmonium modes
$B_s^0 \to J / \psi f_2^\prime(1525)$ and $B_s^0 \to J/\psi K^+K^-$. Within the
framework of the factorization approach and using the perturbative QCD for the
evaluation of the relevant form factors, we find a branching fraction for the
two-body channel of BR$(B_s^{0} \to J/\psi f_2^{\prime}(1525)) = (1.6
{}^{+0.9}_{-0.7})\times 10^{-4}$ which is in agreement with the experimental
values reported by the LHCb and Belle Collaborations. The associated
polarization fractions to this vector-tensor mode are also presented. On the
other hand, non-resonant and resonant contributions to the three-body decay
$B_s^0 \to J/\psi K^+K^-$ are carefully investigated. The dominant
contributions of the resonances $ \phi(1020)$ and $f_2^{\prime}(1525)$ are
properly taken into account. A detailed analysis of the $K^+ K^-$ invariant
mass distributions and Dalitz plot are also performed. The overall result
BR$(B_s^{0} \to J/\psi K^+ K^-) = (9.3^{+1.3}_{-1.1})\times 10^{-4}$ is also in
satisfactory agreement with the experimental information reported by LHCb and
Belle.


title:
Using Neural Networks to Compute Approximate and Guaranteed Feasible
  Hamilton-Jacobi-Bellman PDE Solutions

abstract:
  To sidestep the curse of dimensionality when computing solutions to
Hamilton-Jacobi-Bellman partial differential equations (HJB PDE), we propose an
algorithm that leverages a neural network to approximate the value function. We
show that our final approximation of the value function generates near optimal
controls which are guaranteed to successfully drive the system to a target
state. Our framework is not dependent on state space discretization, leading to
a significant reduction in computation time and space complexity in comparison
with dynamic programming-based approaches. Using this grid-free approach also
enables us to plan over longer time horizons with relatively little additional
computation overhead. Unlike many previous neural network HJB PDE approximating
formulations, our approximation is strictly conservative and hence any
trajectories we generate will be strictly feasible. For demonstration, we
specialize our new general framework to the Dubins car model and discuss how
the framework can be applied to other models with higher-dimensional state
spaces.


title: Scalable Compression of a Weighted Graph

abstract:
  Graph is a useful data structure to model various real life aspects like
email communications, co-authorship among researchers, interactions among
chemical compounds, and so on. Supporting such real life interactions produce a
knowledge rich massive repository of data. However, efficiently understanding
underlying trends and patterns is hard due to large size of the graph.
Therefore, this paper presents a scalable compression solution to compute
summary of a weighted graph. All the aforementioned interactions from various
domains are represented as edge weights in a graph. Therefore, creating a
summary graph while considering this vital aspect is necessary to learn
insights of different communication patterns. By experimenting the proposed
method on two real world and publically available datasets against a state of
the art technique, we obtain order of magnitude performance gain and better
summarization accuracy.


title:
Discovery of a fourth arc in Abell 2626 at 610 MHz with the GMRT:
  Spectral properties and possibilities for the origin

abstract:
  We report the discovery of a fourth eastern arc (Arc E) towards the cool-core
cluster Abell 2626 using 610 MHz Giant Metrewave Radio Telescope observations.
Three arcs towards north, west and south were known from earlier works at 1400
MHz and proposed to have originated in precessing radio jets of the central
active galactic nucleus. The 610 - 1400 MHz integrated spectral indices of the
arcs are in the range 3.2 - 3.6 and the spectral index map shows uniform
distribution along the lengths of the arcs. If associated with A2626, the arcs
have linear extents in the range 79 - 152 kpc. The detection of Arc E favours
the scenario in which a pair of bipolar precessing jets were active and halted
to produce the arc system. Based on the morphological symmetry and spectral
similarity, we indicate a possible role of gravitational lensing. Further high
resolution low frequency observations and measurements of the mass of the
system are needed to disentangle the mystery of this source.


title:
HoTCoffeeh: Hanbury Brown-Twiss correlation functions and radii from
  event-by-event hydrodynamics

abstract:
  $\textbf{HoTCoffeeh}$ ($\textbf{H}$anbury Br$\textbf{o}$wn-$\textbf{T}$wiss
$\textbf{Co}$rrelation $\textbf{f}$unctions and radii $\textbf{f}$rom
$\textbf{e}$vent-by-$\textbf{e}$vent $\textbf{h}$ydrodynamics) is a new
computational tool which determines Hanbury Brown-Twiss (HBT) charged pion
($\pi^+$) correlation functions and radii for event-by-event (EBE)
hydrodynamics with fluctuating initial conditions in terms of Cooper-Frye
integrals, including resonance decay contributions. In this paper, we review
the basic formalism for computing the HBT correlation functions and radii with
resonance decay contributions included, and discuss our implementation of this
formalism in the form of HoTCoffeeh. This tool may be easily integrated with
other numerical packages for the purpose of simulating the evolution of
heavy-ion collisions and thereby extracting predictions for heavy-ion
observables.


title:
Autonomous learning by simple dynamical systems with a discrete-time
  formulation

abstract:
  We present a discrete-time formulation for the autonomous learning
conjecture. The main feature of this formulation is the possibility to apply
the autonomous learning scheme to systems in which the errors with respect to
target functions are not well-defined for all times. This restriction for the
evaluation of functionality is a typical feature in systems that need a finite
time interval to process a unit piece of information. We illustrate its
application on an artificial neural network with feed-forward architecture for
classification and a phase oscillator system with synchronization properties.
The main characteristics of the discrete-time formulation are shown by
constructing these systems with predefined functions.